Ink droplet ejection apparatus and ink jet recorder

Information

  • Patent Grant
  • 6299271
  • Patent Number
    6,299,271
  • Date Filed
    Tuesday, March 30, 1999
    25 years ago
  • Date Issued
    Tuesday, October 9, 2001
    23 years ago
Abstract
An ink droplet ejection apparatus includes a print head having ejection nozzles and three storers store serial ejection data therein and transfer them in order. On the basis of the data output from the storers and transfer data control signals, a transfer data generator makes a logical operation to generate additional pulse data for cancellation of ink pressure wave vibration in order to prevent ink from being ejected or dropped accidentally through the nozzles. The control signals are determined depending on temperature and condition of use.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to ink droplet ejection apparatus for ejecting ink to form an image on a recording medium.




2. Description of Related Art




Conventional recorders which are easy of multiple gradation and colorization include ink jet recorders. Of these recorders, ink droplet ejection apparatus of the drop-on-demand type, which eject printing ink, are coming into wide use because of high ejection efficiency and low running costs.




For example, Japanese Patent Application Laid-Open No. 63-247051 discloses ink droplet ejection apparatus of the shear mode type as ink droplet ejection apparatus of the drop-on-demand type. Piezoelectric material is used in the apparatus disclosed in the publication.

FIGS. 23 and 24

of the drawings accompanying this specification show part of a conventional ink droplet ejection apparatus of the shear mode type.




The apparatus shown in

FIGS. 23 and 24

includes a 64-channel multi-nozzle print head


600


, only five channels of which are shown for simplification. The head


600


includes a bottom wall


601


, at top wall


602


and a number of shear mode actuator walls


603


extending between them. Each actuator wall


603


includes an upper part


605


and a lower part


607


which are made of piezoelectric material. The wall parts


605


and


607


are bonded to the walls


602


and


601


, respectively, and polarized oppositely as shown by arrows


609


and


611


, respectively. The actuator walls


603


are arranged in pairs to define channels


613


between them. Spaces


615


are defined between successive pairs of actuator walls


603


.




At one end of the channels


613


is secured a nozzle plate


617


formed with nozzles


618


for the respective channels. The other end of the channels


613


is connected through a manifold


626


to an ink cartridge or another ink supply (not shown). The manifold


626


includes a front wall


627


and a rear wall


628


. The front wall


627


is formed with holes communicating with the respective channels


613


. The rear wall


628


closes the space in the rear of the front wall


627


between the rear ends of the base wall


601


and top wall


602


. Ink can be supplied from the supply to the space between the front wall


627


and rear wall


628


, and then be distributed to the channels


613


.




Electrodes


619


and


621


are disposed on opposite sides of each actuator wall


603


. The electrodes


619


disposed in the channels


613


are connected to a drive circuit


21


. Under the control of a control circuit


22


, the drive circuit


21


can generate or output a voltage and apply it to these electrodes. The electrodes


621


disposed in the spaces


615


and on both sides of the print head


600


are connected to a ground return


623


.




In operation, the voltage applied to the electrodes


619


in each channel


613


causes the actuator walls


603


facing the channel to deform piezoelectrically in such directions that the channel enlarges in volume. For example, if, as shown in

FIG. 25

of the accompanying drawings, a voltage of E volts is applied to the electrodes


619


in one of the channels


613


, electric fields are generated in the actuator walls


603


defining this channel. As shown by arrows


631


and


632


, the fields are normal to the directions


609


and


611


of polarization. This deforms these walls


603


piezoelectrically in such directions that the channel


613


enlarges to reduce the pressure in the channel to a negative pressure.




The voltage applied to the electrodes


619


is held for a period L/V where L is the channel length and V is the sound velocity in the ink in the channel


613


. While the voltage is applied, ink is supplied from the supply to the channel


613


. The period L/V is the one-way propagation delay time T which it takes for the pressure wave in the channel


613


to be propagated one way longitudinally of the channel.




According to the theory of pressure wave propagation, the negative pressure in the channel


613


reverses into a positive pressure when the period L/V passes after the voltage is applied to the electrodes


619


. If the voltage is returned to zero volt when this period passes after the voltage application, the deformed actuator walls


603


return to their original condition shown in

FIGS. 23 and 24

. This applies a positive pressure to the ink in the channel


613


. This pressure is added to the pressure reversed to be positive. As a result, a relatively high pressure develops in that portion of the channel


613


which is near to the associated nozzle


618


, ejecting ink out through the nozzle. The ejected ink sticks to a surface of printing paper or another recording medium to form an image on it.




The present assignee's Japanese Patent Application Laid-Open Nos. 9-29960, 9-29961 and 9-48112 disclose the step of ejecting ink out through a nozzle


618


by generating pressure wave vibration in the ink in the associated channel


613


, and the step of substantially canceling the residual pressure wave vibration of the ink in the channel after the ejection. This cancellation involves generating an additional pulse after the main drive waveform for the ejection. Specifically, the cancellation involves increasing and decreasing the volume of the channel


613


by applying a voltage of E volts to the associated electrodes


619


at a predetermined time after the ejection and by subsequently returning the voltage to 0 volt. The cancellation damps the residual pressure wave vibration in the channel


613


quickly and early. This prevents ink from being ejected or dropped accidentally through the nozzle


618


by the residual pressure wave vibration. Besides, this enables early transition to the process in accordance with the next print command for this channel. It is therefore possible to form a more exact image on a recording medium, and improve the print speed.




The assignee's Japanese Patent Application Laid-Open No. 10-202858 discloses the steps of ejecting ink out through a nozzle


618


in a print cycle, and thereafter canceling the residual pressure wave vibration in the associated channel


613


if there is no print command for this channel for the following cycle, ibut canceling no such vibration if there is a print command therefor. If there is no print command for the following cycle, ;an accidental drop of ink may occur, and therefore the residual pressure wave vibration should be canceled. This results in better image formation not stained or spotted by scattered ink. If there is a print command for the following cycle, the residual pressure wave vibration in the channel


613


should be utilized positively. Specifically, this vibration should be added to the pressure wave vibration generated in accordance with the print command for this cycle. The addition generates greater pressure wave vibration for ejection of a larger ink droplet through the nozzle


618


. Larger ink droplets increase the print density to form a thicker and clearer image.




It is conceivable that it is possible to damp or control ink meniscus vibration more effectively by switching between the execution and no execution of the vibration cancellation for a particular channel in a particular print cycle selectively depending on, not only whether there is a print command for the following cycle for this channel, but also whether there is a print command for the preceding cycle for the channel. This would stabilize the droplet jet velocity and the ejection, and make it possible to obtain an ink droplet of desired volume, thereby improving the print quality.




The viscosity and other characteristics of the ink in an apparatus vary with the temperature and other conditions at or in which the apparatus is used. It is desirable to perform the foregoing switching arbitrarily and easily depending on this variation as well. It has been desirable to generate a stop pulse for the vibration cancellation securely by means of simple structure or construction, depending on the preceding and/or following print data. It has also been desirable to ease the restrictions on the print waveforms for the cancellation.




SUMMARY OF THE INVENTION




In order to satisfy the foregoing desires, it is an object of the invention to provide an ink droplet ejection apparatus and an ink jet recorder which can switch securely between the execution and no execution of cancellation of ink pressure wave vibration for each cycle depending on whether there is a print command for at least one of the preceding and following cycles. It is another object to provide such an apparatus and a recorder which can modify the switching easily and arbitrarily depending on the conditions of use etc. It is still another object to provide such an apparatus and a recorder which are loose in constraint or limitation on print waveform for vibration cancellation even at a high print clock frequency, and which is high in degree of freedom of print waveform for vibration cancellation, so that suitable vibration cancellation can be made for better print quality.




In accordance with a first aspect of the invention, an ink droplet ejection apparatus is provided which includes:




An ink channel which is filled with ink;




an actuator for changing the volume of the ink channel;




a power source for applying electric signals to the actuator; and




a controller for causing the source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the ink channel by the ejection.




The controller includes a plurality of storers for storing serial print data (ejection data) therein and transferring the stored data in order. The controller also includes an additional pulse data generator for making a logical operation based on the data from the storers and an output data combination selection signal to add an additional pulse to an ejection pulse.




When one of the storers stores therein the data bit for a certain print cycle if they are two storers, the other stores therein the data bit for the preceding or following cycle. When one of the storers stores therein the data bit for a certain print cycle if they are three storers, the others each store therein the data bit for one of the preceding and following cycles. The generator makes the logical operation based on the data from the storers and the combination selection signal to generate additional (stop) pulse data for the vibration cancellation.




There may be a case where no print data bit succeeds consecutive print data bits. More specifically, a certain dot may succeed a dot and precede no dot. In such a case, the ejection of ink is liable to be unstable. It is, however, possible to stabilize the ejection by switching between the execution and no execution of vibration cancellation (addition of stop pulse data).




The logical operation is made on the basis of a series of data from the storers and the combination selection signal to generate additional pulse data for vibration cancellation. This makes it possible to switch between the execution and no execution of vibration cancellation easily and arbitrarily with relatively simple structure, and raises the degree of freedom of print waveform for vibration cancellation.




It is not necessary for the cancellation to damp the pressure wave vibration completely. It may be necessary for the cancellation to damp the vibration to such a degree that no ink can be ejected from the channel.




The additional pulse data generator may include logic gate circuits each associated with one of all combinations of the data from the storers. In accordance with the selection signal, the appropriate gate circuit or circuits output data. By inputting the combination selection signal to the logic gate circuits, it is possible to switch properly between the execution and no execution of vibration cancellation for an arbitrary combination of the data from the storers. This produces the foregoing effect. The gate circuits will be described in detail with reference to

FIG. 4A

for embodiments of the invention.




The combination selection signal may be rewritten externally. By changing the selection signal externally and arbitrarily, it is possible to cancel the pressure wave vibration properly.




The combination selection signal may be determined depending on the temperature or other conditions at or in which the apparatus is used. The additional data generator may include a logical circuit for receiving the ejection data from the storers and the selection signal and making a logical operation of the received data and signal. This determination of the selection signal makes it possible to cancel the pressure wave vibration properly.




The channel may include a plurality of channels. The actuator may include actuators each associated with one of the channels. The apparatus may further comprise an image memory for storing therein print data for the respective channels. One of the storers may be a serializer (parallel-serial converter) for holding the print data transferred in parallel from the memory, and outputting the held data in series to make a parallel-serial conversion of the print data. Another of the storers may be a first shift register for receiving the print data output in series from the serializer, shifting the received data therein, and outputting in series the print data stored therein. Still another of the storers may be a second shift register for receiving the print data output in series from the first register, shifting the received data therein, and outputting in series the print data stored therein.




When the first shift register outputs the data for a certain print cycle, the serializer outputs the data for the following cycle, and the second shift register outputs the data for the preceding cycle. The additional pulse data generator makes a logical operation based on the data output for each of the channels from the serializer and the registers.




In this case, depending on the data for the following and preceding cycles for each channel, it is possible to switch securely between the execution and no execution of vibration cancellation for the certain cycle for the channel. This produces the foregoing effect.




The image memory, the serializer, the shift registers and the additional pulse data generator will be described in detail with reference to

FIGS. 3 and 11

of the drawings.




In accordance with a second aspect of the invention, an ink droplet ejection apparatus is provided which includes:




an ink channel which is filled with ink;




an actuator for changing the volume of the ink channel;




a power source for applying electric signals to the actuator; and




a controller for causing the source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the ink channel by the ejection.




This controller includes three storers for storing serial print data therein and transferring the stored data in order. The controller also includes a logical operator (for making a logical operation based on the print data stored in the storers, and determining whether an additional (stop) pulse should be generated.




This logical operation may be set suitably, and based on a combination of the data bit stored for a certain print cycle in one of the three storers, the data bit stored for the preceding cycle in another, and the data bit stored for the following cycle in the other. If the operation results in the execution of vibration cancellation, a stop pulse is added to the ejection pulse for the certain cycle.




If continuous printing halts, the ejection of ink is liable to be unstable. This apparatus can, however, damp the ink meniscus vibration effectively. This stabilizes the droplet jet velocity and the ejection. It is therefore possible to eject ink droplets of desired volume.




The channel and the actuator of this apparatus may include a plurality of channels and actuators, respectively. The channels are each associated with one of the actuators. The apparatus may further comprise an image memory for storing therein print data for the respective channels. One of the three storers may be a serializer for holding the print data transferred in parallel from the memory, and outputting the held data in series to make a parallel-serial conversion of the print data. Another of the storers may be a first shift register for receiving the print data output in series from the serializer, shifting the received data therein, and outputting in series the print data stored therein. The other of the storers may be a second shift register for receiving the print data output in series from the first register, shifting the received data therein, and outputting in series the print data stored therein.




When the first register outputs the data for a certain print cycle, the serializer outputs the data for the following cycle, and the second register outputs the data for the preceding cycle. The logical operator makes a logical operation based on the print data output for each of the channels from the serializer and the registers.




In this case, depending on the data for the following and preceding cycles for each channel, it is possible to switch securely between the execution and no execution of vibration cancellation for the certain cycle for the channel. This produces the foregoing effect.




Each cycle may include a first period and a second period following the first. The controller may transfer an ejection pulse signal and an additional pulse signal in the first and second periods, respectively. This enables the data to be transferred in series from the controller to the drive circuit, thereby simplifying the wiring.




The logical operator of this apparatus may make a logical operation of the data from the three storers and a selection signal determined depending on temperature or conditions of use. Only by changing the selection signal suitably, it is easy to cancel the pressure wave vibration optimally at each temperature or in each condition of use.




The controller of this apparatus may include a gate array. The array includes the serializer, the shift registers and the logical operator. The controller may also include a drive circuit for driving the actuators with the output from the array. This makes it possible to meet various needs by modifying only the logical circuit of the gate array without modifying the drive circuit, which may be located in a print head unit.




This controller may also include a first serial-parallel converter and a second serial-parallel converter. The first converter receives the print data output in series from one of the storers, and converts the serial print data into parallel data. The second converter receives the additional pulse data output in series from the logical operator, and converts the serial pulse data into parallel data. The controller may further include a switch for switching the output from the two converters cyclically.




Additional pulse data are generated as stated above. The print data and the additional pulse data are input to the first and second serial-parallel converters, respectively. The output from the converters is switched cyclically so that ejection pulses and additional pulses can be processed separately. This enables an arbitrary drive waveform to be produced and used for vibration cancellation even at a higher print frequency.




The two serial-parallel converters and the switch will be described in detail with reference to

FIGS. 10 and 13

of the drawings.




The controller may include a gate array. The array may include the serializer, the shift registers and the logical operator. The controller may also include a drive circuit for driving the actuator with the output from the array. The drive circuit includes the serial-parallel converters and the switch.




This drive circuit may be located in a print head unit, and includes the serial-parallel converters and the switch. This makes it possible to transfer the print data and the stop pulse data via two data lines from the controller to the drive circuit. It is therefore possible to transfer sufficient data, and thereby process data at a high print frequency.




In accordance with a third aspect of the invention, an ink droplet ejection apparatus is provided which includes:




a plurality of channels which are filled with ink;




actuators each for changing the volume of one of the channels;




a memory for storing therein print data for driving the respective actuators;




a controller for transferring in series the print data from the memory;




a first serial-parallel converter for holding the transferred serial data and outputting the held data in parallel and series;




a second serial-parallel converter for holding the data transferred in series from the first converter, and outputting the held data in parallel and series; and




a third serial-parallel converter for holding the data transferred in series from the second converter, and outputting the held data in parallel and series.




When the second converter outputs the data in parallel for a certain cycle, the first converter outputs the data in parallel for the following cycle, and the third converter outputs the data in parallel for the preceding cycle.




This apparatus also includes a logical operator which can generate an additional pulse data bit for each of the channels for the certain cycle by making a logical operation based on the data output for the channel from the three converters.




Applied to each of the actuators are an ejection pulse signal based on the print data for ejection of ink from the associated channel in accordance with a print command for a dot and the signal output from the operator for substantial cancellation of pressure wave vibration caused in the channel by the ejection.




Thus, the logical operation is based on the output from the three serial-parallel converters to generate additional pulse data. This makes it possible to cancel vibration by generating additional pulse data easily and arbitrarily with relatively simple structure, and raises the degree of freedom of print waveform for vibration cancellation.




The actuators, the three serial-parallel converters and the logical operator of this apparatus may be formed on a carriage for moving the ink droplet ejection apparatus along a printing medium. In this case, the operator for generating additional pulses is located on the carriage. Therefore, without modifying the body of an image recorder in particular, it is possible to modify the ink droplet ejection apparatus of the recorder to an apparatus which can generate arbitrary additional pulses.




In accordance with a fourth aspect of the invention, an ink droplet ejection apparatus is provided which includes:




a channel which is filled with ink;




an actuator for changing the volume of the channel;




a power source for applying electric signals to the actuator;




a controller for causing the source to apply to the actuator an ejection pulse signal for ejection of ink from the channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the channel by the ejection; and




an image memory for storing therein a series of print data for ejecting ink from the channel.




This controller includes:




three storers for storing therein and transferring in order print data stored in the memory;




a logical operator for generating the additional pulse, as the need arises, by making a logical operation based on the print data stored for three consecutive data (dots) in the storers, the operator storing the generated additional pulse in the memory; and




a transferor for transferring to the actuator the print data and the additional pulse data stored in the memory.




When one of these storers stores therein the data bit (print data) for a certain print cycle, another stores therein the data bit for the preceding cycle, and the other stores therein the data bit for the following cycle. The logical operation is based on the data from the storers to generate an additional pulse data bit, which is stored in the image memory. The transferor transfers the stored print data and the additional pulse data to the actuator.




There may be a case where a certain dot succeeds a dot and precedes no dot. In such a case, this apparatus makes it possible to switch between the execution and no execution of vibration cancellation for the certain dot. It is therefore possible to stabilize the ejection of ink.




This apparatus will be described in detail with reference to

FIGS. 20-22

of the drawings.




The storers of this apparatus may be a first register, a second register and a third register for holding the data from the image memory. When the second register holds the data bit for a certain print cycle, the first and third registers hold the data for the following and preceding cycles, respectively. The logical operation is based on the data from the three registers. This makes it possible to switch securely between the execution and no execution of vibration cancellation for the certain cycle depending on the data for the preceding and following cycles.




The logical operator of this apparatus may make a logical operation of the data from the three storers and a selection signal determined depending on temperature or conditions of use. Only by changing the selection signal properly, it is easy to cancel vibration optimally at each temperature or in each condition of use.




The controller of this apparatus may include a gate array, which includes the three registers and the logical operator. The controller may also include a drive circuit for driving the actuator with the output from the array. This makes it possible to meet various needs by modifying only the logical circuit of the gate array without modifying the drive circuit, which may be located in a print head unit.




According to the fifth aspect of the invention, a ink jet recorder is provided, which comprises: an ink jet head including an ink channel which is filled with ink, and an actuator for changing the volume of the ink channel; a power source for applying electric signals to the actuator; and a controller for causing the source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the ink channel by the ejection; the controller including: a plurality of storers for storing serial print data therein and outputting the stored data in order; an additional pulse data generator for making a logical operation based on the data from the storers and an output data combination selection signal to add an additional pulse to an ejection pulse.




According to the sixth aspect of the invention, a ink jet recorder is provided, which comprises: an ink jet head including an ink channel which is filled with ink, and an actuator for changing the volume of the channel; a power source for applying electric signals to the actuator; and a controller for causing the source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the ink channel by the ejection; the controller including: three storers for storing serial print data therein and transferring the stored data in order; and a logical operator for making a logical operation based on the print data stored in the storers, and determining whether an additional pulse should be generated.




According to the seventh aspect of the invention, a ink jet recorder is provided, which comprises: an ink jet head including a plurality of channels which are filled with ink, and actuators each for changing the volume of one of the channels; a memory for storing therein print data for driving the respective actuators; a controller for transferring in series the print data from the memory; a first serial-parallel converter for holding the transferred serial data and outputting the held data in parallel and series; a second serial-parallel converter for holding the data transferred in series from the first converter, and outputting the held data in parallel and series; a third serial-parallel converter for holding the data transferred in series from the second converter, and outputting the held data in parallel and series; the first converter outputting the data in parallel for a cycle following a certain cycle when the second converter outputs the data in parallel for the certain cycle; the third converter outputting the data in parallel for a cycle preceding the certain cycle when the second converter outputs the data in parallel for the certain cycle; and a logical operator for generating an additional pulse data bit for each of the channels for the certain cycle by making a logical operation based on the data output for the channel from the three converters; whereby an ejection pulse signal based on the print data for ejection of ink from each of the channels in accordance with a print command for a dot and the signal output from the operator for substantial cancellation of pressure wave vibration caused in the channel by the ejection are applied to the associated actuator.




According to the eighth aspect of the invention, a ink jet recorder is provided, which comprises: an ink jet head including a channel which is filled with ink, and an actuator for changing the volume of the channel; a power source for applying electric signals to the actuator; a controller for causing the source to apply to the actuator an ejection pulse signal for ejection of ink from the channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the channel by the ejection; and an image memory for storing therein a series of print data for ejecting ink from the channel; the controller including: three storers for storing therein and transferring in order the print data stored in the memory; a logical operator for generating the additional pulse by making a logical operation based on the print data stored for three consecutive data in the storers, the operator storing the generated additional pulse in the memory; and a transferor for transferring to the actuator the print data and the additional pulse data stored in the memory.











BRIEF DESCRIPTION OF THE DRAWINGS




Preferred embodiments of the invention will be described with reference to the accompanying drawings, in which:





FIG. 1

is a schematic perspective view of the common structure of ink jet printers fitted with ink ejection apparatus according to the embodiments;





FIG. 2

is a block diagram of the electric system of the printer fitted with the apparatus according to a first embodiment of the invention;





FIG. 3

is a block diagram of the control circuit shown in

FIG. 2

;





FIG. 4A

is a circuit diagram of the transfer data generator shown in

FIG. 3

;





FIG. 4B

is a table of print data combinations and transfer data control signals for this generator;





FIG. 5

is a time chart of signals and data during the stop pulse data transfer period of a print cycle of this embodiment;





FIG. 6

is a time chart of signals and data during the ejection pulse data transfer period of this cycle;





FIG. 7

is a block diagram of the drive circuit shown in

FIG. 2

;





FIG. 8

is another time chart of signals and data in this embodiment;





FIG. 9

is a block diagram of the electric system of the printer fitted with the apparatus according to a second embodiment of the invention;





FIG. 10

is a block diagram of the drive circuit shown in

FIG. 9

;





FIG. 11

is a block diagram of the control circuit shown in

FIG. 9

;





FIG. 12

is a time chart of signals and data in this embodiment;





FIG. 13

is a block diagram of the drive circuit of the apparatus according to a third embodiment of the invention;





FIG. 14

is a time chart of signals and data in this embodiment;





FIG. 15

is a block diagram of the electric system of the printer fitted with the apparatus according to a fourth embodiment of the invention;





FIG. 16

is a block diagram of the drive circuit shown in

FIG. 15

;





FIG. 17

is a time chart of signals and data in this embodiment;





FIG. 18

is a block diagram of the drive circuit of the apparatus according to a fifth embodiment of the invention;





FIG. 19

is a time chart of signals and data in this embodiment;





FIG. 20

is a block diagram of the control circuit of the apparatus according to a sixth embodiment of the invention;





FIG. 21

is an image map of the print data area in the image memory of this apparatus;





FIG. 22

is an image map of the stop pulse data area in this memory;





FIG. 23

is a sectional elevation of the print head which is common to the conventional apparatus and the apparatus according to the embodiments;

FIG. 23

is taken on the line X—X of

FIG. 24

;





FIG. 24

is a sectional plan taken on the line Y—Y of

FIG. 23

;





FIG. 25

is a sectional elevation of the print head of

FIGS. 23 and 24

, showing the head operation.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




With reference to

FIG. 1

, the common structure of the ink jet printers embodying the invention includes a 64-channel multi-nozzle print head


600


. Because this head is basically identical in mechanical structure to the conventional head


600


shown in

FIGS. 23-25

, the description of it will be omitted with the same reference numerals used for the counterparts.




The common structure also includes a printer frame, which includes a pair of side plates


503


. A guide rod


501


and a guide rail


502


extend in parallel between the plates


503


. A carriage


504


is supported on the rod


501


and rail


502


slidably along them. The carriage


504


is fastened to a timing belt


505


, which can be driven by a carriage motor


506


to reciprocate the carriage. The belt


505


extends between a pair of pulleys


507


, which are positioned near both ends of the rod


501


and rail


502


. One of the pulleys


507


is connected to the drive shaft of the motor


506


.




The carriage


504


carries a head unit


508


, which includes the print head


600


and a drive circuit (not shown). The drive circuit is a one-chip IC, which is connected via a flexible harness cable (not shown) to a control circuit (not shown) in the printer body. The carriage


504


also carries an ink cartridge


509


mounted removably on its rear to supply ink to the channels


613


of the head


600


.




The common structure further includes a feed mechanism LF for feeding a sheet of printing paper P. The mechanism LF includes a platen roller


511


, which can be driven by a feed motor


510


to feed the sheet P perpendicularly to the directions in which the carriage


504


moves. The shaft


512


of the roller


511


is supported rotatably by one of the side plates


503


and part of the printer frame.




Positioned on one side of the feed mechanism LF is a maintenance and recovery mechanism RM for maintaining and recovering good condition of ink ejection from the print head


600


. The mechanism RM includes a suction mechanism


513


and a preservation cap


514


. While the head


600


is used, the ink in it may dry or dehydrate, and air bubbles may be produced in it. Besides, ink droplets may stick to the outer side of the nozzle plate


617


of the head


600


. This may cause defective ejection of ink. In order to eliminate the defective condition of ejection, the suction mechanism


513


sucks ink out through the nozzles


618


with the cap


514


capping the nozzle plate


617


. While the printer is not used, the cap


514


caps the nozzle plate


617


to function additionally as a cover for preventing ink from drying.





FIG. 2

shows the electric system of the printer fitted with the apparatus according to the first embodiment.




The control system of this printer includes a one-chip microcomputer


11


, a ROM


12


and a RAM


13


. The microcomputer


11


is connected to a control panel


14


, motor energization circuits


15


and


16


, a paper sensor


17


, a home position sensor


18


, a current position sensor


19


, etc. The panel


14


can be used for the users' print instructions etc. The energization circuits


15


and


16


can energize the carriage motor


506


and the feed motor


510


, respectively. The paper sensor


17


can detect the front end of a sheet of printing paper P as a recording medium. The home position sensor


18


can detect the home position of a carriage


504


. The current position sensor


19


can detect the current or moving position of the carriage


504


.




The printer includes a 64-channel multi-nozzle print head


600


which is basically identical to the conventional head


600


shown in

FIGS. 23-25

. This head


600


can be driven by a drive circuit


121


, which is a one-chip IC. The drive circuit


121


is controlled by a control circuit


122


, which is a gate array. The drive circuit


121


is connected to the electrodes


619


(

FIG. 24

) in the channels


613


of the head


600


. Under the control of the control circuit


122


, the drive circuit


121


can generate a voltage which is suitable for the head


600


, and apply the voltage to the electrodes


619


.




The microcomputer


11


is connected to the ROM


12


, the RAM


13


and the control circuit


122


via an address bus


23


and a data bus


24


. In accordance with the program stored in advance in the ROM


12


, the microcomputer


11


generates a print timing signal TS and a control signal CS, and transfer them to the control circuit


122


.




The control circuit


122


causes print data transferred from a personal computer


26


or other external apparatus via a Centronics interface


27


to be stored in an image memory


25


. On the basis of Centronics data transferred from this computer


26


or the like via the interface


27


, the control circuit


122


generates a Centronics data receive interrupt signal IS, and transfers it to the microcomputer


11


.




In accordance with the print timing signal TS and the control signal CS, the control circuit


122


generates:




transfer data TD which are the print data for forming the images on printing paper P on the basis of the print data stored in the image memory


25


; and




a transfer clock TCK, a strobe signal STB and a print clock PCK for synchronism with the transfer data TD.




The generated data and signals TD, TCK, STB and PCK are transferred to the drive circuit


121


through a flexible harness cable


28


, which connects the control circuit


122


in the printer body and the drive circuit


121


on the carriage


504


.




With reference to

FIG. 3

, the control circuit


122


includes a data setting circuit


41


. The control circuit


122


also includes a 64-bit serializer (serial-parallel converter)


42


, a first 64-bit shift register


43


and a second 64-bit shift register


44


as three devices for storing data. The control circuit


122


further includes a transfer data generator


45


as a device for generating additional pulse data, and a controller


47


.




In accordance with the print timing signal TS and the control signal CS from the microcomputer


11


, the controller


47


generates a setting command SC, a serialization control signal SCS, two shift register control signals SRC


1


and SRC


2


, and eight transfer data control signals TDC


0


-TDC


7


for controlling the circuits


41


-


45


. The controller


47


also generates the strobe signal STB, the transfer clock TCK and the print clock PCK.




The data setting circuit


41


reads out print data in parallel from the image memory


25


, and outputs them in parallel to the serializer


42


in accordance with the setting command SC.




In accordance with the serialization control signal SCS, the serializer


42


receives the print data Ch


0


-Ch


63


for each print cycle in parallel from the respective channels of the data setting circuit


41


, and holds them in itself. When pulses of a shift clock SCK (

FIGS. 5 and 6

) rise, the serializer


42


outputs the data Ch


0


-Ch


63


in that order, by one bit at a time, in series through its serial output terminal OUT. This makes a parallel-serial conversion of the data Ch


0


-Ch


63


. At the same time, the serial data Ch


0


-Ch


63


from the serializer


42


are input as ejection data A to the transfer data generator


45


, and to one serial input terminal IN


1


of the first shift register


43


.




In accordance with the shift register control signal SRC


1


, the first shift register


43


receives the serial print data Ch


0


-Ch


63


in series from the serializer


42


, and holds them in itself. When shift clock pulses SCK rise, this register


43


outputs the data Ch


0


-Ch


63


in that order, by one bit at a time, in series through its serial output terminal OUT. The serial data Ch


0


-Ch


63


from this terminal OUT are input as ejection data B to the transfer data generator


45


, and to the other serial input terminal IN


2


of the register


43


when the control signal SRC


1


changes over.




In accordance with the shift register control signal SRC


2


, the second shift register


44


receives the serial print data Ch


0


-Ch


63


in series from the first shift register


43


, and holds them in itself. When shift clock pulses SCK rise, this register


44


outputs the data Ch


0


-Ch


63


in that order, by one bit at a time, in series through its serial output terminal OUT. The serial data Ch


0


-Ch


63


from the register


44


are input as ejection data C to the transfer data generator


45


.




When the first shift register


43


outputs the print data Ch


0


-Ch


63


for a certain print cycle as ejection data B, the serializer


42


outputs the print data Ch


0


-Ch


63


for the following cycle as ejection data A, and the second shift register


44


outputs the print data Ch


0


-Ch


63


for the preceding cycle as ejection data C.




The transfer data generator


45


functions as a device for generating additional pulse data. The generator


45


receives the serial ejection data A-C from the serializer


42


and the shift registers


43


and


44


. The generator


45


makes logical operations of the data A-C and the transfer data control signals TDC


0


-TDC


7


, which may be suitably determined depending on temperature and other conditions. The generator


45


outputs transfer data TD to the drive circuit


121


in synchronism with the transfer clock TCK, the strobe signal STB and the print clock PCK.




As shown in

FIG. 8

, the transfer data TD consist of ejection pulse data ED on the ejection of ink from the channels


613


of the print head


600


and stop pulse data SD on the cancellation of the residual pressure wave vibration in the channels.




If the print head


600


did not have 64 channels, it would only be necessary for the bits of the serializer


42


and shift registers


43


and


44


to be equal in number to the channels of the head.




With reference to

FIG. 4A

, the transfer data generator


45


includes logical circuits, which are eight AND gates


50


and an OR gate


51


. Each AND gate


50


has four input terminals. The OR gate


51


has eight input terminals, which are connected to the output terminals of the respective AND gates


50


. The AND gates


50


receive the respective transfer data control signals TDC


0


-TDC


7


from the controller


47


and the ejection data A-C from the serializer


42


and shift registers


43


and


44


. The data A-C are input to the AND gates


50


directly or through inverter gates, as shown in

FIG. 4A

, for all combinations of the data. By suitably selecting the logical level of each of the signals TDC


0


-TDC


7


, it is possible to output any of the data A-C or a signal based on any combination of them.





FIG. 4B

shows all the combinations of the ejection data A-C for stop pulse generation, and the transfer data control signals TDC


0


-TDC


7


for the respective combinations. For example, if only TDC


7


is “1” and TDC


0


-TDC


6


are “0”, an additional stop pulse is generated and output as a bit of transfer data TD from the OR gate


51


only when the data A-C are all “1”. If the data A-C are “1” or high in logical level, they represent dots. If these data are “0” or low in logical level, they represent no dots.




As shown in

FIG. 8

, a print cycle Cn succeeds a print cycle Cn−1. The cycle Cn precedes a print cycle Cn+1 (not shown). Each cycle includes a stop pulse data transfer period and an ejection pulse data transfer period after the stop pulse data transfer period.





FIGS. 5 and 6

show the stop pulse data transfer period and the ejection pulse data transfer period, respectively, of the cycle Cn−1 (FIG.


8


). In the stop pulse data transfer period, the stop pulse data SDn−1 (

FIG. 8

) for the cycle Cn−1 are transferred as transfer data TD. In the ejection pulse data transfer period, the ejection pulse data EDn (

FIG. 8

) for the next cycle Cn are transferred as transfer data TD.




With reference to

FIG. 5

, the operation of the control circuit


122


during the stop pulse data transfer period will be explained.




The serializer


42


receives the parallel print data Ch


0


n+1-Ch


63


n+1 for the cycle Cn+1 from the data setting circuit


41


, and outputs the received data as ejection data A in series through its serial output terminal OUT when shift clock pulses SCK rise. The serial data Ch


0


n+1-Ch


63


n+1 from the serializer


42


are input in the serial input terminal IN


1


of the first shift register


43


.




The print data Ch


0


n-Ch


63


n for the cycle Cn have been stored in the first shift register


43


, which outputs them as ejection data B in series through its serial output terminal OUT when the shift clock pulses SCK rise. The serial data Ch


0


n-Ch


63


n from this register


43


are input in the serial input terminal IN of the second shift register


44


.




The print data Ch


0


n−1-Ch


63


n−1for the cycle Cn−1 have been stored in the second shift register


44


, which outputs them as ejection data C in series through its serial output terminal OUT when the shift clock pulses SCK rise.




The transfer data generator


45


receives the serial ejection data A-C and the transfer data control signals TDC


0


-TDC


7


. The generator


45


then makes logical operations for each channel, and outputs stop pulse data SDn−1, which are transferred to the drive circuit


121


.




During the stop pulse data transfer period, only the transfer data control signal TDC


3


is made “1” and the other signals TDC


0


-TDC


2


and TDC


4


-TDC


7


are made “0”. Consequently, only when a bit of data A is “0” and the associated bits of data B and C are “1”, the AND gate


50


associated with the signal TDC


3


outputs “1” while the other gates


50


output “0”. In this case, the bit of stop pulse data SDn−1 output from the OR gate


51


is “1”. That is to say, in this case, the bit of transfer data TD for a dot (B) is “1”, which represents a stop pulse, if the dot succeeds a dot (C) and precedes no dot (A).




Thus, if there are print commands for the cycles Cn−1 and Cn for one of the channels, and if there is no print command for the cycle Cn+1 for this channel, the bit of stop pulse data SDn for the cycle Cn for this channel is, “1” to cancel the residual pressure wave vibration in the channel. The other combinations of the print commands for the cycles Cn−1, Cn and Cn+1 cause the bit of stop pulse data SDn to be “1”.




The conditions for adding a stop pulse are not limited to the foregoing data combination, but arbitrary. In particular, depending on the temperature or other conditions at or in which the printer is used, it is possible to change one or more of the transfer data control signals TDC


0


-TDC


7


so as to either add or omit a stop pulse as shown in Japanese Patent Laid-Open Publication No. H.9-48112. It is possible to change the logical operation expressions by modifying one or more of the logical circuits in the control circuit


122


, or storing desired patterns of the transfer data control signals in the ROM


12


or the RAM


13


. The transfer data control signals stored in the RAM


13


can be rewritten through the personal computer


26


.




With reference to

FIG. 6

, the operation of the control circuit


122


during the ejection pulse data transfer period will be explained.




When the stop pulse data SDn−1 have been transferred, the print data Ch


0


n+1-Ch


63


n+1 have been stored in the first shift register


43


. When shift clock pulses SCK rise, this register


43


outputs the stored data Ch


0


n+1-Ch


63


n+1 in series through its serial output terminal OUT. The serial data Chn+1 from this terminal OUT are input to the serial input terminal IN


2


of the register


43


.




During the ejection pulse data transfer period, the transfer data control signals TDC


0


, TDC


1


, TDC


4


and TDC


5


are made “0” Rand the other signals TDC


2


, TDC


3


, TDC


6


and TDC


7


are made “1”. This, regardless of the states of the ejection data A and C, causes the ejection data B to be output from any of the AND gates


50


associated with the signals TDC


2


, TDC


3


, TDC


6


and TDC


7


. Then, the OR gate


51


outputs the ejection data B as ejection pulse data.




With reference to

FIG. 7

, the drive circuit


121


includes a serial-parallel converter


31


and a data latch


32


. The circuit


121


also includes


64


AND gates


33


and output circuits


34


. The output circuits


34


are connected to the electrodes


619


in the respective channels


613


of the print head


600


.




The converter


31


is a 64-bit shift register, which receives transfer data TD transferred in synchronism with the transfer clock TCK serially from the control circuit


122


. When pulses of the transfer clock TCK rise, the converter


31


converts the received serial data TD into parallel data PD


0


-PD


63


.




When a pulse of the strobe signal STB from the control circuit


122


rises, the latch


32


latches the parallel data PD


0


-PD


63


.




The AND gates


33


output drive data A


0


-A


63


, which are the logical products of the parallel data PD


0


-PD


63


from the latch


32


and a pulse of the print clock PCK from the control circuit


122


.




On the basis of the drive data A


0


-A


63


, the output circuits


34


can generate a voltage which is suitable for the print head


600


, and output it to the associated channel electrodes


619


.




If the print head


600


did not have 64 channels, it would only be necessary for the bits of the converter


31


, the AND gates


33


, and the output circuits


34


to be equal in number to the channels of the head.




The parallel data PD


0


-PD


63


from the converter


31


are associated with the respective channels


613


of the print head


600


. Accordingly, the bits of the transfer data TD from the control circuit


122


and the print data Ch


0


-Ch


63


in it are associated with the respective channels


613


. In accordance with the bits of the transfer data TD and the print data Ch


0


-Ch


63


, the voltage can be generated for application to the electrodes


619


in the channels


613


to control the ejection of ink from the channels when ink is ejected and when the residual pressure wave vibration in the channels is canceled.




The same voltage is generated to eject ink and cancel the vibration.




With reference to

FIG. 8

, the operation of the apparatus according to this embodiment will be described.




In every print cycle, stop pulse data SD and ejection pulse data ED are transferred. The strobe signal STB includes pulses STBe for the ejection pulse data ED and pulses STBs for the stop pulse data SD. The print clock PCK includes pulses PCKe for the ejection pulse data ED and pulses PCKs for the stop pulse data SD. Pulses STBe, STBn, PCKe and PCKn are transferred in every print cycle.




In each print cycle, ejection of ink can be followed by cancellation of vibration. In other words, a print clock pulse PCKe is transferred and thereafter a print clock pulse PCKs is transferred in each cycle.




In the cycle Cn−1 , the stop pulse data SDn−1 for this cycle are transferred, and thereafter the ejection pulse data EDn for the next cycle Cn are transferred. In the cycle Cn, the stop pulse data SDn for this cycle are transferred, and thereafter the ejection pulse data EDn+1 for the next cycle Cn+1 are transferred.




In the cycle Cn−1 , the strobe pulse STBen−1 associated with the ejection pulse data EDn−1 (not shown) for this cycle are transferred, and thereafter the strobe pulse STBsn−1 associated with the stop pulse data SDn−1 for this cycle are transferred. In the next cycle Cn, the strobe pulse STBen associated with the ejection pulse data EDn for this cycle are transferred, and thereafter the strobe pulse STBsn associated with the stop pulse data SDn for this cycle are transferred.




In the cycle Cn−1 , the print clock pulse PCKen−1 associated with the ejection pulse data EDn−1 (not shown) for this cycle are transferred, and thereafter the print clock pulse PCKsn−1 associated with the stop pulse data SDn−1 for this cycle are transferred. In the next cycle Cn, the print clock pulse PCKen associated with the ejection pulse data EDn for this cycle are transferred, and thereafter the print clock pulse PCKsn associated with the stop pulse data SDn for this cycle are transferred.




With reference to

FIG. 8

, the operation of the drive circuit


211


will be explained.




If the print clock PCK is high in logical level, the output from each AND gate


33


depends on the associated output from the latch


32


, that is, the associated bit of transfer data TD. If the print clock PCK is low in logical level, the output from the AND gates


33


is inhibited and low in logical level regardless of the output from the latch


32


. In other words, the clock PCK functions as an enabling signal for the AND gates


33


to produce drive data A


0


-A


63


.




If one or more bits of the parallel data PD


0


-PD


63


from the latch


32


are high in logical level when the print clock PCK is high in logical level, the drive data bit or bits from the associated AND gate or gates


33


are high in logical level. Then, the associated output circuit or circuits


34


generate a voltage, and output it to the electrodes


619


in the associated channel or channels


613


of the print head


600


. If one or more bits of the parallel data PD


0


-PD


63


from the latch


32


are low in logical level even when the print clock PCK is high in logical level, the drive data bit or bits from the associated AND gate or gates


33


are low in logical level. Then, the associated output circuit or circuits


34


generate no voltage.




Each print clock pulse PCKe rises at a point of time t1 and falls at a point of time t2. The width of each print clock pulse PCKe equals the one-way propagation delay time T. Each print clock pulse PCKs rises at a point of time t3 and falls at a point of time t4. The time “d” between the point t2 and the middle point tM between the points t3 and t4 is 2.5 times as long as the time T.




If a bit of the ejection pulse data ED for a certain print cycle is high in logical level, the rise of the print clock pulse PCKe at the point t1 in this cycle generates electric fields in the associated actuator walls


603


, as shown in FIG.


25


. The fields enlarge the associated channel


613


in volume, reducing the pressure in the channel. Then, ink flows into the channel


613


. In the meantime, the enlarged volume generates pressure wave vibration. The pressure due to the vibration increases and reverses into positive pressure, which reaches its peak about when the one-way propagation delay time T has just passed.




When the print clock pulse PCKe falls at the point t2 in this cycle, the channel


613


decreases in volume, developing pressure. This pressure and the pressure which has reversed to a plus are added together. This develops relatively high pressure near the nozzle


618


in the channel


613


, ejecting ink out through the nozzle. The ejected ink sticks to the sheet of printing paper P, forming an image on it.




After the point t3 in this cycle, the pressure in the channel


613


reverses from a plus to a minus. If the associated bit of the stop pulse data SD for this cycle is high in logical level, the rise of the print clock pulse PCKs at the point t3 in this cycle rapidly reduces the pressure which is still positive.




Before the point t4 in this cycle, the pressure in the channel


613


reverses to a minus. When the print clock pulse PCKs falls at the point t4 , the negative pressure increases rapidly. This cancels the pressure wave vibration, rapidly damping the vibration. The cancellation of the pressure wave vibration prevents ink from being ejected accidentally through the nozzle


618


, and makes it possible to be ready earlier for the step in accordance with the next print command. It is therefore possible to form a more accurate image on the sheet P, and shorten the print cycles, thereby improving the print speed.




The width W of each print clock pulse PCKs is half (0.5) of the one-way propagation delay time T. The print clock pulses PCKs are generated to cancel the pressure wave vibration in the channel or channels


613


. Besides, the width W is short and very different from a value which is an odd number of times as large as the time T. Therefore, the pulses PCKs enable no ink to be ejected from the channel or channels


613


.




Thus, this embodiment makes it possible to switch securely between the execution and no execution of vibration cancellation in each print cycle, depending on whether there is a print command for one or each of the preceding and following cycles. When such selective switching is made, the control circuit


122


can accurately control the voltage application by the drive circuit


121


to electrodes


619


.




The drive circuit


121


may be conventional. In this case, by constructing only the control circuit


122


as stated above, it is possible to provide an ink ejection apparatus which can switch between the execution and no execution of vibration cancellation. As stated above, the drive circuit


121


, which is a one-chip IC, and the print head


600


form the head unit


508


. The unit


508


is mounted on the carriage


504


, but the control circuit


122


is connected via the harness cable


28


to the drive circuit


2


. It is therefore possible to realize this embodiment by replacing only the control circuit


22


of the conventional ink ejection apparatus (

FIGS. 23-25

) with the circuit


122


without modifying the head unit. This can lower remodeling costs.





FIG. 9

shows the electric system of the printer fitted with the apparatus according to the second embodiment. The basic structure of this printer is similar to the structure shown in

FIG. 2

for the first embodiment, and includes a microcomputer


11


, a control circuit


222


and a drive circuit


221


. The two embodiments differ mainly as follows.




In accordance with a print timing signal TS and a control signal CS, the control circuit


222


generates and outputs to the drive circuit


221


:




ejection pulse data ED on the ejection of ink from the channels


613


(

FIGS. 23-25

) for image formation on printing paper P on the basis of print data stored in the image memory


25


;




stop pulse data SD on the cancellation of the residual pressure wave vibration in the channels


613


on the basis of print data stored in this memory


25


; and




a switching signal SS for switching the data ED and SD.




The microcomputer


11


outputs to the control circuit


222


eight transfer data control signals TDC


0


-TDC


7


for controlling the data ED and SD. The signals TDC


0


-TDC


7


can be changed as the need arises.




The drive circuit


221


switches the data ED and SD.




With reference to

FIG. 10

, the drive circuit


221


includes a pair of serial-parallel converters


31


A and


31


B, each of which is a 64-bit shift register,


64


electronic switches


35


and a data latch


32


. The circuit


221


also includes


64


AND gates


33


and output circuits


34


. The latch


32


, the AND gates


33


and the output circuits


34


are similar in structure to the counterparts of the first embodiment.




The converter


31


A receives ejection pulse data ED transferred in series synchronously with the transfer clock TCK from the control circuit


222


. When pulses of the clock TCK rise, the converter


31


A converts the input serial data ED into parallel data EPD


0


-EPD


63


. The converter


31


B receives stop pulse data SD transferred in series synchronously with the transfer clock TCK from the control circuit


222


. When pulses of the clock TCK rise, the converter


31


B converts the input serial data SD into parallel data SPD


0


-SPD


63


.




Each switch


35


changes over from one of its nodes A and B to the other in accordance with the switching signal SS transferred from the control circuit


222


. If the switches


35


change over to their respective nodes A, they select the parallel data EPD


0


-EPD


63


. If the switches


35


change over to their respective nodes B, they select the parallel data SPD


0


-SPD


63


. The switches


35


output the selected data to the latch


32


.




With reference to

FIG. 11

, the basic structure of the control circuit


222


is similar to the counterpart of the circuit


122


of the first embodiment, and consists of a data setting circuit


41


, a serializer


42


, a first shift register


43


, a second shift register


44


, a transfer data generator


45


and a controller


47


. The generator


45


is identical with the counterpart shown in FIG.


4


A.




This serializer


42


outputs serial print data Ch


0


-Ch


63


as ejection data A through its serial output terminal OUT. The data A are input as ejection pulse data ED to the serial-parallel converter


31


A of the drive circuit


221


.




This first shift register


43


outputs serial print data Ch


0


-Ch


63


as ejection data B through its serial output terminal OUT to the transfer data generator


45


and the second shift register


44


, without feeding them back to itself.




This second shift register


44


outputs serial print data Ch


0


-Ch


63


as ejection data C through its serial output terminal OUT to the transfer data generator


45


.




This transfer data generator


45


outputs stop pulse data SD on the basis of the ejection data A-C and the transfer data control signals TDC


0


-TDC


7


from the microcomputer


11


. As is the case with the first embodiment, the signals TDC


0


-TDC


7


might otherwise be output from the controller


47


.




As is the case with the first embodiment, the controller


47


generates a strobe signal STB, a transfer clock TCK and a print clock PCK. The controller


47


also generates the switching signal SS. These signals are input to the drive circuit


221


.




With reference to

FIG. 12

, the operation of the apparatus according to the second embodiment will be explained. The print clock PCK and the strobe signal STB are similar to the counterparts of the first embodiment.




The ejection pulse data EDn for a print cycle Cn and the stop pulse data SDn−1 for the preceding cycle Cn−1 are transferred at the same time in the cycle Cn−1. The ejection pulse data EDn+1 for the following cycle Cn+1 (not shown) and the stop pulse data SDn for the cycle Cn are transferred at the same time in the cycle Cn.




In the cycle Cn−1, the print clock pulse PCKen−1 associated with the ejection pulse data EDn−1 (not shown) for this cycle is transferred, and thereafter the print clock pulse PCKsn−1 associated with the stop pulse data SDn−1 for this cycle is transferred. In the cycle Cn, the print clock pulse PCKen associated with the ejection pulse data EDn for this cycle is transferred, and thereafter the print clock pulse PCKsn associated with the stop pulse data SDn for this cycle is transferred.




The switching signal SS is transferred in association with the strobe signal STB. In each of the cycles Cn−1 and Cn, the switching signal SS switches the switches


35


of the drive circuit


221


to the nodes B when the strobe pulse STBsn−1 or STBsn for the associated stop pulse data SDn−1 or SDn is transferred. Otherwise, in each of the cycles Cn−1 and Cn, the signal SS switches the switches


35


to the nodes A.




When the switches


35


are switched to the nodes A in accordance with the switching signal SS, the latch


32


latches parallel data EPD


0


-EPD


63


output from the converter


31


A. When the switches


35


are switched to the nodes B, the latch


32


latches parallel data SPD


0


-SPD


63


output from the converter


31


B.




When the ejection pulse data EDn−1 for the cycle Cn−1 are latched in the latch


32


, the stop pulse data SDn−1 for this cycle are stored in the converter


31


B, and the ejection pulse data EDn for the next cycle Cn are stored in the converter


31


A. After the ejection pulse data EDn−1 are output, the associated stop pulse data SDn−1 are output, and subsequently the next ejection pulse data EDn are output.




The latched data are output synchronously with the print clock PCK to the print head


600


for ejection of ink and cancellation of vibration.




A time chart (not shown) for the control circuit


222


would be similar to FIG.


5


. This chart would be a time chart for the period when the ejection pulse data EDn+1 and the stop pulse data SDn are transferred as transfer data in the cycle Cn shown in FIG.


12


.





FIG. 13

shows the drive circuit


321


of the apparatus according to the third embodiment. The circuit


321


is a slight modification of the circuit


221


shown in

FIG. 10

for the second embodiment. The circuit


321


includes a pair of data latches


32


A and


32


B, which are associated with serial-parallel converters


31


A and


31


B, respectively. Electronic switches


35


can selectively output data from one of the latches


32


A and


32


B to AND gates


33


.





FIG. 14

is a time chart of the print clock PCK, the strobe signal STB, the ejection pulse data ED, the stop pulse data SD and the switching signal SS in this embodiment.




As shown in

FIG. 14

, the ejection pulse data EDn and the stop pulse data SDn for a print cycle Cn are transferred at the same time in the preceding cycle Cn−1. In the cycle Cn, the ejection pulse data EDn+1 and the stop pulse data SDn+1 for the following cycle Cn+1 (not shown) are transferred at the same time. As shown with a broken line in

FIG. 11

, the ejection pulse data ED transferred to the drive circuit


321


are the serial data B from the first shift register


43


of the control circuit


222


.




Transferred in the cycle Cn−1 are the strobe pulse STBn−1 associated with the ejection pulse data EDn−1 (not shown) and the stop pulse data SDn−1 (not shown) for this cycle. Transferred in the cycle Cn are the strobe pulse STBn associated with the ejection pulse data EDn and the stop pulse data SDn for this cycle. The switching signal SS is transferred in association with the print clock PCK.




In each of the print cycles Cn−1 and Cn, the switches


35


of the drive circuit


321


are switched to their respective nodes B in accordance with the switching signal SS when the print clock pulse ICKsn−1 or ICKsn for the associated stop pulse data SDn−1 or Sdn is transferred. Otherwise, the switches


39


are switched to their respective nodes A in accordance with the signal SS.




When the switches


35


are switched to their nodes A, the AND gates


33


of the drive circuit


321


receive the parallel data EPD


0


-EPD


63


output from the converter


31


A and latched by the latch


32


A. When the switches


35


are switched to their nodes B, the gates


33


receive the parallel data SPD


0


-SPD


63


output from a the converter


31


B and latched by the latch


32


B.




The data latched in the latches


32


A and


32


B are output to the print head


600


synchronously with the print clock PCK to eject ink from one or more of the channels


613


and to cancel the residual pressure wave vibration in the channel or channels, as is the case with the foregoing embodiments.




A time chart for the period when the ejection pulse data EDn and the stop pulse data SDn are transferred would be equivalent to FIG.


5


.




Thus, the control circuit


222


generates the serial ejection pulse data EDn and the serial stop pulse data SDn for the cycle Cn at the same time. The serial data EDn and SDn are transferred at the same time to the drive circuit


321


, where the converters


31


A and


31


B convert the serial data EDn and SDn, respectively, at the same time into parallel data EPD


0


-EPD


63


and SPD


0


-SPD


63


, respectively. The parallel data EPD


0


-EPD


63


and SPD


0


-SPD


63


are output to the latches


32


A and


32


B, respectively, where they are latched at the same time in accordance with the strobe signal STB. The switches


35


change over in accordance with the switching signal SS associated with the print clock PCK. The switches


35


output either the latched data EPD


0


-EPD


63


or the latched data SPD


0


-SPD


63


to the AND gates


33


, which output drive data A


0


-A


63


in synchronism with the print clock PCK.




Therefore, as shown in

FIG. 14

, it is possible to shorten the time interval between the point t5 when the print clock pulse PCKsn−1 for the stop pulse data SDn−1 falls and the point t1 when the print clock pulse PCKen for the ejection pulse data EDn rises. It is also possible to shorten the time interval between the point t2 when this pulse PCKen falls and the point t3 when the print clock pulse PCKsn for the stop pulse data SDn rises. Consequently, this embodiment can further shorten the period of each print cycle in comparison with the second embodiment. This improves the print speed further.





FIG. 15

shows the electric system of the printer fitted with the apparatus according to the fourth embodiment. The basic structure of this printer is similar to the counterpart of the first embodiment, and includes a microcomputer


11


, a conventional control circuit


422


and a drive circuit


421


. The two embodiments differ mainly as follows.




Additional pulses for vibration cancellation are generated by the drive circuit


421


, not the control circuit


422


. The control circuit


422


outputs, to the drive circuit


421


, eight switching control signals SWC


0


-SWC


7


for switching print data combinations, in place of the transfer data control signals TDC


0


-TDC


7


for determining the condition for vibration cancellation.




With reference to

FIG. 16

, the drive circuit


421


includes three serial-parallel converters


31


A,


31


B and


31


C, each of which is a 64-bit shift register,


64


pulse data generators


36


and a data latch


32


. The circuit


421


also includes


64


AND gates


33


and output circuits


34


.




The converter


31


A receives transfer data TD transferred in series synchronously with a transfer clock TCK from the control circuit


422


. When pulses of this clock TCK rise, the converter


31


A converts the input serial data TD into parallel data A. The converter


31


A outputs the input data TD in series to the converter


31


B. When transfer clock pulses TCK rise, the converter


31


B converts the input serial data TD into parallel data B, and outputs the data TD in series to the converter


31


C. When transfer clock pulses TCK rise, the converter


31


C receives the serial data TD in series from the converter


31


B, and converts them into parallel data C.




Each pulse data generator


36


includes logical circuits, and functions as a device for generating additional pulse data. In accordance with the switching control signals SWC


0


-SWC


7


from the control circuit


422


, the generators


36


make logical operations of the parallel data A, B and C to generate ejection pulse data for ejection of ink and stop pulse data for cancellation of vibration. The signals SWC


0


-SWC


7


designate a condition for generating a stop pulse, that is to say, one or more combinations of consecutive print pulse data. These signals may be determined depending on temperature or other conditions.




The data latch


32


latches stop pulse data and ejection pulse data in order when pulses of the strobe signal STB from the control circuit


422


rise. The latch


32


outputs the latched data to the AND gates


33


.




Each AND gate


33


outputs a bit of drive data A


0


-A


63


, which is the logical product of the associated bit of the stop pulse data or the ejection pulse data and the print clock PCK from the control circuit


422


.




On the basis of each bit of the drive data A


0


-A


63


, the associated output circuit


34


can generate voltage suitable for the print head


600


. The circuit


34


outputs the voltage to the electrodes


619


in the associated channel


613


of the head


600


.




The parallel data A, B or C from each of the converters


31


A-


31


C are associated with the respective channels


613


. Therefore, the stop pulse data and the ejection pulse data from the generators


36


are associated with the respective channels


613


.




Each pulse data generator


36


is equivalent to the transfer data generator


45


shown in FIG.


4


A. The switching control signals SWC


0


-SWC


7


are equivalent to the transfer data control signals TDC


0


-TDC


7


(FIGS.


4


A and


4


B). The AND gates


50


(

FIG. 4A

) of each generator


36


receive the associated parallel data A-C from the converters


31


A-


31


C. Similarly to the first embodiment, the gates


50


output the logical products of the input data A-C and signals SWC


0


-SWC


7


. The OR gate


51


(

FIG. 4A

) of each generator


36


outputs stop pulse data and ejection pulse data. In other words, each generator


36


outputs stop pulse data or ejection pulse data in accordance with the signals SWC


0


-SWC


7


. By suitably selecting the logical level of each of the signals SWC


0


-SWC


7


, similarly to the first embodiment, it is possible to output any of the data A-C or a signal based on any combination of them.




With reference to

FIG. 17

, the operation of the apparatus according to the fourth embodiment will be explained.




Transfer data TD are transferred in every print cycle. Stop pulse data and ejection pulse data from the generators


36


are transferred in association with the strobe signal STB and the print clock PCK in each print cycle.




When transfer clock pulses TCK rise in each print cycle, transfer data TD are transferred in series from the converter


31


A to the converter


31


B and from the converter


31


B to the converter


31


C, and shifted in each of them by one bit at a time.




After the transfer data TD for one print cycle are transferred, the parallel data B from the converter


31


B may be the ejection pulse data for the “n”th printing. In this case, the parallel data A from the converter


31


A are the ejection pulse data for the “n+1”th printing, and the parallel data C from the converter


31


C are the ejection pulse data for the “n−1”th printing.




The switching control signals SWC


0


-SWC


7


are transferred in association with the strobe signal STB. In each print cycle, the print clock pulse PCKe associated with the ejection pulse data for this particular cycle is transferred, and thereafter the print clock pulse PCKs associated with the stop pulse data for the cycle is transferred. In each print cycle, the strobe pulse STBe for the ejection pulse data and the strobe pulse STBs for the stop pulse data are transferred in succession.




The pulse data generators


36


receive the parallel data A C and the switching control signals SWC


0


-SWC


7


, and make logical operations. First in each print cycle, SWC


0


-SWC


3


are made “


0


” and SWC


4


-SWC


7


are made “1”. Consequently, regardless of the data B and C, the OR gates


51


(

FIG. 4A

) of the generators


36


output ejection pulse data which are identical with the data A stored in the converter


31


A. After the strobe pulse STBe for the ejection pulse data rises and the latch


32


latches these data, the data in the converters


31


A-


31


C shift so that the new transfer data TD and the data A and B become new data A-C, respectively. Thereafter, only the control signal SWC


3


is made “1” and the other signals SWC


0


-SWC


2


and SWC


4


-SWC


7


are made “0”. Consequently, the AND gate


50


associated with the signal SWC


3


of each generator


36


outputs “1” only when the associated bit of data A is “0” and the associated bits of data B and C are “1”. In this case, the stop pulse data bit for a dot (B) is “1” for addition of a stop pulse if the dot succeeds a dot (C) and precedes no dot (A). The stop pulse data synthesized by the generators


36


are latched by the latch


32


when the strobe pulse STBs rises.




Similarly to the foregoing embodiments, the AND gates


33


of the drive circuit


421


output drive data A


0


-A


63


to the respective output circuits


34


in accordance with the conditions of the latch


32


and the print clock PCK.




Thus, by constructing the drive circuit


421


as stated above, and by using the conventional control circuit


422


, which generates no stop pulse data, it is possible to provide an ink ejection apparatus which can switch between the execution and no execution of the vibration cancellation.





FIG. 18

shows the drive circuit


521


of the apparatus according to the fifth embodiment. This circuit


521


is a slight modification of the circuit


421


shown in

FIG.16

of the fourth embodiment. The circuit


521


includes three serial-parallel converters


31


A,


31


B and


31


C, which are associated with three data latches


32


A,


32


B and


32


C, respectively. The circuit


521


also includes


64


pulse data generators


36


, AND gates


33


and output circuits


34


.




When a pulse of the strobe signal STB transferred from the control circuit


422


(

FIG. 15

) rises, the latches


32


A-


32


C latch parallel data output from the converters


31


A-


31


C, respectively.




The generators


36


are identical with the counterparts shown in FIG.


16


. The generators


36


output the logical products of the switching control signals SWC


0


-SWC


7


from the control circuit


422


and the parallel data A-C from the latches


32


A-


32


C, respectively. The products are ejection pulse data and stop pulse data, which are input to the AND gates


33


.




With reference to

FIG. 19

, the operation of the drive circuit


521


will be explained.




The converters


31


A-


31


C operate similarly to the counterparts of the foregoing embodiment. When a strobe pulse STB rises, the latches


32


A-


32


C latch print data output from the converters


31


A-


31


C, respectively. First in each print cycle, the switching control signals SWC


0


, SWC


1


, SWC


4


and SWC


5


are made “0” and the other signals SWC


2


, SWC


3


, SWC


6


and SWC


7


are made “1”. This makes the generators


36


output the parallel data B as ejection pulse data to the AND gates


33


. The gates


33


output the logical products of the ejection pulse data and the associated print clock pulse PCKe to the output circuits


34


.




Subsequently, with the latched data A-C held, only the switching control signal SWC


3


is made “1” and the other signals SWC


0


-SWC


2


and SWC


4


-SWC


7


are made “0”. Consequently, the AND gate


50


(

FIG. 4A

) associated with the signal SWC


3


of each pulse data generator


36


outputs “1” only if the associated data bit A is “0” and the associated data bits B and C are “1”. Thus, the generators


36


output stop pulse data to the AND gates


33


, which output the logical products of these data and the associated print clock pulse PCKs to the output circuits


34


.




Thus, in the drive circuit


521


, the parallel data from the serial-parallel converters


31


A-


31


C are latched once in the data latches


32


A-


32


C, respectively. In accordance with the switching control signals SWC


0


-SWC


7


associated with the print clock PCK, the output from the pulse data generators


36


is switched between ejection pulse data and stop pulse data. The switched data are input to the AND gates


33


. It is therefore possible to shorten the time interval between the point when the print clock pulse PCKs associated with the stop pulse data for each print cycle falls and the point when the print clock pulse PCKe associated with the ejection pulse data for the next cycle rises. It is also possible to shorten the time interval between the point when the print clock pulse PCKe associated with the ejection pulse data for each cycle falls and the point when the print clock pulse PCKs associated with the stop pulse data for this cycle rises. This can shorten the period of each cycle in comparison with the fourth embodiment, and improve the print speed further.





FIG. 20

shows the control circuit


622


of the printer fitted with the apparatus according to the sixth embodiment. The electric system of this printer is similar to the system shown in FIG.


2


. The printer includes a drive circuit (not shown) which is similar to the circuit


121


shown in FIG.


7


. The printer also includes a microcomputer


11


(FIG.


2


), which generates a print timing signal TS and a control signal CS.




The control circuit


622


includes a first register


52


, a second register


53


and a third register


54


as three devices for storing data. The circuit


622


also includes a stop pulse data generator


56


as a device for generating additional pulse data, a data transferor


55


and a controller


57


.




In accordance with the print timing signal TS and the control signal CS, the controller


57


generates a memory address signal, a register control signal, eight stop pulse data control signals and a data transfer control signal for controlling the memory


25


, the registers


52


-


54


, the generator


56


and the transferor


55


, respectively. The controller


57


also generates a strobe signal STB, a transfer clock TCK and a print clock PCK f or synchronism with transfer data TD.




As shown in

FIG. 20

, the printer includes an image memory


25


, which has a print data area


25




a


and a stop pulse data area


25




b.






Print data PD stored in the area


25




a


of the memory


25


are read out in series by one byte at a time in the printing direction, and input to each of the registers


52


-


54


. When the print data PDn for a print cycle Cn are stored in the second register


53


, the print data PDn−1 for the preceding cycle Cn−1 are stored in the third register


54


, and the print data PDn+1 for the following cycle Cn+1 are stored in the first register


52


. In accordance with the register control signal, the registers


52


-


54


output the stored data as serial print data A-C, respectively, to the stop pulse data generator


56


.




The stop pulse data generator


56


includes logical circuits, and is identical with the transfer data generator shown in

FIG. 4A

of the first embodiment. The generator


56


makes logical operations of the print data A-C from the registers


52


-


54


and the stop pulse data control signals SPC


0


-SPC


7


from the controller


57


. The signals SPC


0


-SPC


7


are equivalent to the transfer data control signals TDC


0


-TDC


7


(FIGS.


4


A and


4


B). The generator


56


generates serial stop pulse data SD, which are stored in the stop pulse data area


25




b


of the memory


25


.




The data transferor


55


reads out print data PD and stop pulse data SD alternately from the areas


25




a


and


25




b


of the image memory


25


, and outputs transfer data TD in series. The transfer data TD consist of ejection pulse data ED for ejection of ink from one or more of the channels


613


of the print head


600


and stop pulse data SD for cancellation of the residual pressure wave vibration in the channel or channels.




The operation of this apparatus will be explained.




A time chart of the print clock PCK, the strobe signal STB and the transfer data TD would be identical with

FIG. 8

for the first embodiment.





FIGS. 21 and 22

are image maps of the print data area


25




a


and the stop pulse data area


25




b


, respectively, of the image memory


25


. In

FIGS. 21 and 22

, black squares represent dots, and white squares represent no dots. Eight bytes (rows


0


-


7


) of print data PD are processed at the same time. As shown in

FIG. 21

, a byte of print data PDn (B) succeeds a byte of print data PDn−1 (C) and precedes a byte of Print data PDn+1 (A).




Only the stop pulse data control signal SPC


3


is made “1” and the other signals SPC


0


-SPC


2


and SPC


4


-SPC


7


are made “0”. Consequently, only when a bit of data A is “0” and the associated data B and C are “1”, the AND gate


50


(

FIG. 4A

) associated with it of the stop pulse data generator


56


outputs “1”. In other words, an additional stop pulse is generated for a dot (B) following a dot (C) and preceding no dot (A). The stop pulse data SD from the generator


56


are stored in the area


25




b


of the image memory


25


.

FIG. 22

shows the stop pulse data SD associated with the print data PD shown in FIG.


21


.




In accordance with the data transfer control signal, the data transferor


55


read out print data PD and stop pulse data SD from the image memory


25


, and outputs them as transfer data TD to the drive circuit.




As shown in

FIGS. 7 and 8

for the first embodiment, 64 print data are input in synchronism with the transfer clock TCK to the serial-parallel converter


31


of the drive circuit of this sixth embodiment. The data latch


32


latches the parallel data from the converter


31


in accordance with the strobe signal STB. The AND gates


33


output the logical products of the latched data and the print clock PCK to the output circuits


34


. 64 stop pulse data are processed likewise.




Thus, by constructing the control circuit


622


as stated above, and by using a conventional drive circuit, it is possible to provide an ink ejection apparatus which can switch between the execution and no execution of the vibration cancellation.




The invention is not limited to the foregoing embodiments, but various modifications may be made as follows:




(1) In each embodiment, only one print clock pulse is generated for ejection pulse data in each print cycle. Otherwise, two or more print clock pulses might be generated. In this case, the pulses are equal in number to the ink droplets ejected from each channel


613


. Therefore, a larger number of print clock pulses for the ejection pulse data result in a larger number of ejected ink droplets. This increases the print density to form a thicker and clearer image.




(2) In each embodiment, the width of the print clock pulses for ejection pulse data is equal to the one-way propagation delay time T. Otherwise, the pulse width might be about an odd number of times as large as the time T.




(3) In each embodiment, the width of the print clock pulses for stop pulse data is half (0.5) of the one-way propagation delay time T. Otherwise, this pulse width might be any other value as far as the pulses can cause the residual pressure wave vibration in the channels


613


to be canceled securely without causing ink to be ejected from the channels.




(4) In each print cycle of each embodiment, the print clock pulse for ejection pulse data falls at a point of time t2 , and the print clock pulse for stop pulse data rises and falls at points of time t3 and t4 , respectively. The time “d” between the point t2 and the middle point tM between the points t3 and t4 is 2.5 times as long as the one-way propagation delay time T. The time “d” might, however, be any other value as far as the residual pressure wave vibration can be canceled securely.




(5) In each embodiment, the output circuits


34


output the same voltage for ink ejection and vibration cancellation. Otherwise, the circuits


34


might output a lower voltage for vibration cancellation than for ink ejection, or a negative voltage.




(6) In each embodiment, the piezoelectric deformation of the upper parts


605


and lower parts


607


of the actuator walls


603


changes the volume of the channels


613


to eject ink. Otherwise, one of the parts


605


and


607


of each actuator wall might be made of material which cannot deform piezoelectrically. In this case, the piezoelectric deformation of the other part


605


or


607


deforms the one part to eject ink.




(7) In each embodiment, the channels


613


alternate with the spaces


615


. Otherwise, no spaces


615


might be formed, and the channels


613


might adjoin.




(8) In each embodiment, the invention is applied to the printer in which the print head


600


can reciprocate with the carriage


504


. The invention may also be applied to other printers like line printers each of which has a print head fixed to its body.




(9) In each embodiment, the invention is applied to the printer for printing by receiving data from a personal computer. The invention may also be applied to word processors, facsimile machines, etc. into each of which an ink ejection apparatus is incorporated as a printing mechanism.



Claims
  • 1. An ink droplet ejection apparatus, comprising:an ink channel which is filled with ink; an actuator for changing the volume of the ink channel; a power source for applying electric signals to the actuator; and a controller for causing the power source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the ink channel by the ejection; the controller including: a plurality of storers for storing serial print data therein and outputting the stored data in order; an additional pulse data generator for making a logical operation based on the data from the storers and an output data combination selection signal to add an additional pulse to an ejection pulse.
  • 2. The apparatus defined in claim 1, wherein the data generator includes logic gate circuits each associated with one of all combinations of the data from the storers, the gate circuits outputting data in accordance with the selection signal.
  • 3. The apparatus defined in claim 1, wherein the selection signal is externally rewritable.
  • 4. The apparatus defined in claim 1, wherein the selection signal is determined depending on temperature or conditions of use, the data generator including a logical circuit for receiving the print data from the storers and the selection signal and for making a logical operation.
  • 5. The apparatus defined in claim 1, wherein the ink channel includes a plurality of channels, the actuator including actuators each associated with one of the channels;the apparatus further comprising an image memory for storing therein print data for the respective channels; the storers including: a serializer for holding the print data transferred in parallel from the memory, and outputting the held data in series to make a parallel-serial conversion of the print data; a first shift register for receiving the print data output in series from the serializer, shifting the received data therein, and outputting in series the print data stored therein; and a second shift register for receiving the print data output in series from the first shift register, shifting the received data therein, and outputting in series the print data stored therein; the serializer outputting the data for a cycle following a certain cycle when the first shift register outputs the data for the certain cycle; the second shift register outputting the data for a cycle preceding the certain cycle when the first shift register outputs the print data for the certain cycle; the data generator making a logical operation based on the data output for each of the channels from the serializer and the first and second shift registers.
  • 6. An ink droplet ejection apparatus, comprising:an ink channel which is filled with ink; an actuator for changing the volume of the channel; a power source for applying electric signals to the actuator; and a controller for causing the power source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the ink channel by the ejection; the controller including: three storers for storing serial print data therein and transferring the stored data in order; and a logical operator for making a logical operation based on the print data stored in the storers, and determining whether an additional pulse should be generated.
  • 7. The apparatus defined in claim 6, wherein the ink channel includes a plurality of channels, the actuator including actuators each associated with one of the channels;the apparatus further comprising an image memory for storing therein print data for the respective channels; the storers including: a serializer for holding the print data transferred in parallel from the memory, and outputting the held data in series to make a parallel-serial conversion of the print data; a first shift register for receiving the print data output in series from the serializer, shifting the received data therein, and outputting in series the print data stored therein; and a second shift register for receiving the print data output in series from the first register, shifting the received data therein, and outputting in series the print data stored therein; the serializer outputting the print data for a cycle following a certain cycle when the first shift register outputs the print data for the certain cycle; the second register outputting the print data for a cycle preceding the certain cycle when the first register outputs the print data for the certain cycle; the logical operator making a logical operation based on the print data output for each of the channels from the serializer and the first and second shift registers.
  • 8. The apparatus defined in claim 7, wherein each cycle includes a first period and a second period following the first period, the controller transferring an ejection pulse signal and an additional pulse signal in the first and second periods, respectively.
  • 9. The apparatus defined in claim 6, wherein the logical operation is based on the print data from the storers and a selection signal determined depending on temperature or conditions of use.
  • 10. The apparatus defined in claim 7, wherein the controller includes:a gate array, which includes the serializer, the shift registers and the logical operator; and a drive circuit for driving the actuators with the output from the gate array.
  • 11. The apparatus defined in claim 6, wherein the controller further includes: a first serial-parallel converter for receiving the print data output in series from one of the storers, and for converting the serial print data into parallel data;a second serial-parallel converter for receiving the additional pulse data output in series from the logical operator, and for converting the serial pulse data into parallel data; and a switch for switching the output from the two converters cyclically.
  • 12. The apparatus defined in claim 11, wherein the controller includes:a gate array, which includes the serializer, the shift registers and the logical operator; and a drive circuit for driving the actuator in accordance with the output for switching the drive circuit including the first and second serial-parallel converters and the switch.
  • 13. An ink droplet ejection apparatus comprising:a plurality of channels which are filled with ink; actuators each for changing the volume of one of the channels; a memory for storing therein print data for driving the respective actuators; a controller for transferring in series the print data from the memory; a first serial-parallel converter for holding the transferred serial data and outputting the held data in parallel and series; a second serial-parallel converter for holding the data transferred in series from the first converter, and outputting the held data in parallel and series; a third serial-parallel converter for holding the data transferred in series from the second converter, and outputting the held data in parallel and series; the first converter outputting the data in parallel for a cycle following a certain cycle when the second converter outputs the data in parallel for the certain cycle; the third converter outputting the data in parallel for a cycle preceding the certain cycle when the second converter outputs the data in parallel for the certain cycle; and a logical operator for generating an additional pulse data bit for each of the channels for the certain cycle by making a logical operation based on the data output for the channel from the three converters; whereby an ejection pulse signal based on the print data for ejection of ink from each of the channels in accordance with a print command for a dot and the signal output from the operator for substantial cancellation of pressure wave vibration caused in the channel by the ejection are applied to the associated actuator.
  • 14. The apparatus defined in claim 13, wherein the actuators, the three serial-parallel converters and the logical operator are formed on a carriage for moving the ink droplet ejection apparatus along a printing medium.
  • 15. An ink droplet ejection apparatus, comprising:a channel which is filled with ink; an actuator for changing the volume of the channel; a power source for applying electric signals to the actuator; a controller for causing the power source to apply to the actuator an ejection pulse signal for ejection of ink from the channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the channel by the ejection; and an image memory for storing therein a series of print data for ejecting ink from the channel; the controller including: three storers for storing therein and transferring in order the print data stored in the memory; a logical operator for generating the additional pulse by making a logical operation based on the print data stored for three consecutive data in the storers, the operator storing the generated additional pulse in the memory; and a transferor for transferring to the actuator the print data and the additional pulse data stored in the memory.
  • 16. The apparatus defined in claim 15, wherein the storers include first, second and third registers for holding the print data transferred from the image memory,the second register holding the print data for a certain cycle; the first register holding, when the second register holds the print data for the certain cycle, the print data for a cycle following the certain cycle; and the third register holding, when the second register holds the print data for the certain cycle, the print data for a cycle preceding the certain cycle; the logical operator making a logical operation based on the print data from the first, second and third registers.
  • 17. The apparatus defined in claim 15, wherein the logical operation is based on the print data from the storers and a selection signal determined depending on temperature or conditions of use.
  • 18. The apparatus defined in claim 16, wherein the controller includes:a gate array, which includes the three registers and the logical operator; and a drive circuit for driving the actuator with the output from the array.
  • 19. An ink jet recorder, comprising:an ink jet head including an ink channel which is filled with ink, and an actuator for changing the volume of the ink channel; a power source for applying electric signals to the actuator; and a controller for causing the power source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the ink channel by the ejection; the controller including: a plurality of storers for storing serial print data therein and outputting the stored data in order; an additional pulse data generator for making a logical operation based on the data from the storers and an output data combination selection signal to add an additional pulse to an ejection pulse.
  • 20. An ink jet recorder comprising:an ink jet head including an ink channel which is filled with ink, and an actuator for changing the volume of the channel; a power source for applying electric signals to the actuator; and a controller for causing the source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the ink channel by the ejection; the controller including: three storers for storing serial print data therein and transferring the stored data in order; and a logical operator for making a logical operation based on the print data stored in the storers, and determining whether an additional pulse should be generated.
  • 21. An ink jet recorder comprising:an ink jet head including a plurality of channels which are filled with ink, and actuators each for changing the volume of one of the channels; a memory for storing therein print data for driving the respective actuators; a controller for transferring in series the print data from the memory; a first serial-parallel converter for holding the transferred serial data and outputting the held data in parallel and series; a second serial-parallel converter for holding the data transferred in series from the first converter, and outputting the held data in parallel and series; a third serial-parallel converter for holding the data transferred in series from the second converter, and outputting the held data in parallel and series; the first converter outputting the data in parallel for a cycle following a certain cycle when the second converter outputs the data in parallel for the certain cycle; the third converter outputting the data in parallel for a cycle preceding the certain cycle when the second converter outputs the data in parallel for the certain cycle; and a logical operator for generating an additional pulse data bit for each of the channels for the certain cycle by making a logical operation based on the data output for the channel from the three converters; whereby an ejection pulse signal based on the print data for ejection of ink from each of the channels in accordance with a print command for a dot and the signal output from the operator for substantial cancellation of pressure wave vibration caused in the channel by the ejection are applied to the associated actuator.
  • 22. An ink jet recorder, comprising:an ink jet head including a channel which is filled with ink, and an actuator for changing the volume of the channel; a power source for applying electric signals to the actuator; a controller for causing the power source to apply to the actuator an ejection pulse signal for ejection of ink from the ink channel in accordance with a print command for a dot and an additional pulse signal for substantial cancellation of pressure wave vibration caused in the channel by the ejection; and an image memory for storing therein a series of print data for ejecting ink from the channel; the controller including: three storers for storing therein and transferring in order the print data stored in the memory; a logical operator for generating the additional pulse by making a logical operation based on the print data stored for three consecutive data in the storers, the operator storing the generated additional pulse in the memory; and a transferor for transferring to the actuator the print data and the additional pulse data stored in the memory.
Priority Claims (6)
Number Date Country Kind
10-087524 Mar 1998 JP
10-093762 Apr 1998 JP
10-093763 Apr 1998 JP
10-093764 Apr 1998 JP
10-093764 Apr 1998 JP
11-019946 Jan 1999 JP
US Referenced Citations (3)
Number Name Date Kind
5028936 Bartky et al. Jul 1991
5736994 Takahashi Apr 1998
6145949 Takahashi Nov 2000
Foreign Referenced Citations (6)
Number Date Country
0 827838 A Jun 1998 EP
63-247051 Oct 1988 JP
9-48112 Feb 1997 JP
9-29960 Feb 1997 JP
9-29961 Feb 1997 JP
10-202858 Aug 1998 JP