Patent Grant
10279586
This application claims priority from Japanese Patent Application No. 2016-176932 filed Sep. 9, 2016. The entire content of the priority application is incorporated herein by reference.
This disclosure relates to a method of printing a test pattern in a printer that performs printing by ejecting liquid from nozzles, and to a printer that performs printing by ejecting liquid from nozzles.
An inkjet printer as an example of a printer is known that performs printing by ejecting liquid from nozzles. The inkjet printer is a so-called a serial type and can perform bidirectional printing. The inkjet printer prints a plurality of ruled-line patterns, and allows a user to select a suitable ruled-line pattern among the plurality of ruled-line patterns. By determining ejection timing based on the selected ruled-line pattern, deviation of droplet landing positions in a scanning direction at the time when a print head is moved to one side of the scanning direction and when the print head is moved to the other side is suppressed in bidirectional printing.
According to one aspect, this specification discloses a method of printing a test pattern in a printer including: a liquid ejection head having a plurality of nozzles and a plurality of drive elements configured to cause the plurality of nozzles to eject a liquid droplet; a heat generator that generates heat when the plurality of drive elements is driven; and a temperature sensor configured to detect a temperature of the liquid ejection head. The method includes printing a related-information acquisition pattern as the test pattern in a particular state by driving the plurality of drive elements to eject a liquid droplet from the plurality of nozzles based on the temperature detected by the temperature sensor. The related-information acquisition pattern is a pattern for acquiring related information relating to at least one of an ejection amount and a liquid droplet landing position of the liquid droplet ejected from each of the plurality of nozzles. The liquid droplet landing position is a position at which the liquid droplet ejected from each of the plurality of nozzles lands on a recording medium. The particular state is a state where a temperature difference between the temperature detected by the temperature sensor and an actual temperature of the liquid ejection head is constant.
According to another aspect, this specification also discloses a printer. The printer includes a liquid ejection head, a heat generator, a temperature sensor, and a controller. The liquid ejection head has a plurality of nozzles and a plurality of drive elements configured to cause the plurality of nozzles to eject a liquid droplet. The temperature sensor is configured to detect a temperature of the liquid ejection head. The controller is configured to drive the plurality of drive elements to eject the liquid droplet from the plurality of nozzles based on a temperature detected by the temperature sensor. The heat generator generates heat when the plurality of drive elements is driven. The controller is configured to: perform a determining process of determining whether the printer is in a first state where a temperature difference between the temperature detected by the temperature sensor and an actual temperature of the liquid ejection head is constant or in a second state where the temperature difference varies with time; and a pattern printing process of, after determining that the printer is in the first state in the determining process, controlling the liquid ejection head to print a related-information acquisition pattern as a test pattern. The related-information acquisition pattern is a pattern for acquiring related information relating to at least one of an ejection amount and a liquid droplet landing position of the liquid droplet ejected from each of the plurality of nozzles. The liquid droplet landing position is a position at which a liquid droplet ejected from each of the plurality of nozzles lands on a recording medium.
It is normally in the first state when printing is performed by the printer. Hence, a test pattern is printed by the printer and, based on the print results, various adjustments are performed in the first state. The printer is sometimes not in the first state, for example, just after start of driving drive elements. The actual temperature of the liquid ejection head relative to the temperature detected by the temperature sensor is different between the first state and a state that is not the first state. When the temperature of the liquid ejection head changes, the viscosity of liquid in the liquid ejection head changes and an ejection amount and ejection speed of liquid from the nozzles also change. When the ejection speed changes, a liquid droplet landing position changes. Hence, if a test pattern for acquiring information relating to the ejection amount and liquid droplet landing position of liquid is printed in a state that is not the first state and if the ejection amount and liquid droplet landing position in the first state are adjusted based on the print results, the ejection amount and liquid droplet landing position of liquid droplet in the first state cannot be adjusted appropriately.
In this disclosure, the test pattern for acquiring information relating to the ejection amount or liquid droplet landing position of liquid from the nozzles is printed in the first state. Thus, the ejection amount, droplet landing position, and so on, of liquid in the first state can be adjusted appropriately based on the printed test pattern.
Embodiments in accordance with this disclosure will be described in detail with reference to the following figures wherein:
The inventors of this disclosure found that, when a liquid ejection head is continued to be driven, the inkjet printer eventually becomes a first state where a temperature difference between a temperature detected by a temperature sensor and an actual temperature of the liquid ejection head is constant, and before becoming the first state, a period of a second state exists where the temperature difference between the temperature detected by the temperature sensor and the actual temperature of the liquid ejection head varies with time.
In the above-mentioned inkjet printer, as the temperature in the print head changes, the viscosity of liquid in the print head changes and the ejection speed of liquid changes. Thus, in the above-mentioned inkjet printer, when a ruled-line pattern is printed in the second state, droplet landing positions of liquid in the printed ruled-line pattern are deviated in the scanning direction from droplet landing positions when printing is performed in the first state. As a result, if the ruled-line pattern is printed in the second state and ejection timing is determined based on the selected ruled-line pattern, the determined ejection timing is not an appropriate ejection timing in the first state.
Further, if the viscosity of liquid in the liquid ejection head changes, the ejection amount of liquid from a nozzle changes. Thus, for example, if a test pattern for adjusting an ejection amount of liquid is printed in the second state and the ejection amount of liquid is adjusted based on the print results of this test pattern, there is a possibility that the ejection amount of liquid is not appropriate in the first state.
An example of an object of this disclosure is to provide a method of printing a test pattern for appropriately adjusting droplet landing positions and ejection amounts of liquid, and to provide a printer.
An aspect of this disclosure will be described while referring to the accompanying drawings.
<Overall Configuration of Printer>
As shown in
The inkjet head 3 is mounted on the carriage 2 and ejects ink from a plurality of nozzles 45 formed on a nozzle surface 3a that is a lower surface of the carriage 2. The conveying roller 4a is located at an upstream side of the inkjet head 3 in a conveyance direction perpendicular to the scanning direction. The conveying roller 4b is located at a downstream side of the inkjet head 3 in the conveyance direction. The conveying rollers 4a, 4b are connected to a conveying motor 77 (see
The platen 5 is located between the conveying roller 4a and the conveying roller 4b in the conveyance direction. The platen 5 is located at a lower side of the inkjet head 3 and faces the nozzle surface 3a. The platen 5 supports, from downward, a part of a recording sheet P facing the nozzle surface 3a, the recording sheet P being conveyed by the conveying rollers 4a, 4b. The medium sensor 6 is mounted on the carriage 2 in a part at the upstream side of the inkjet head 3 in the conveyance direction.
The medium sensor 6 detects a leading end of a recording sheet P that is fed from a sheet tray (not shown) and is conveyed to proximity of the inkjet head 3. The medium sensor 6 acquires luminance based on a light amount of reflection light of light emitted toward the platen 5, for example. Here, the platen 5 has a black color. Before the recording sheet P reaches the medium sensor 6, light emitted from the medium sensor 6 hits the black platen 5, and hence the light amount of reflection light is small and the acquired luminance is small. In contrast, after the leading end of the recording sheet P reaches a position facing the medium sensor 6, light emitted from the medium sensor 6 hits the white recording sheet P. Hence, the light amount of reflection light is large and the acquired luminance is large. By using this, the medium sensor 6 detects the leading end of the recording sheet P based on the acquired luminance.
<Inkjet Head>
Next, a structure of the inkjet head 3 will be described. As shown in
<Channel Unit>
The channel unit 21 is formed of four plates 31 to 34 that are laminated vertically. Among the four plates 31 to 34, the upper three plates 31 to 33 are formed of a metal material such as stainless steel and the lowest plate 34 is formed of a synthetic resin material such as polyimide.
In the plate 31, a plurality of pressure chambers 40 are formed. The pressure chambers 40 have a substantially elliptical shape elongated in the scanning direction in a plan view. The plurality of pressure chambers 40 form pressure chamber arrays 39 by being arranged in the conveyance direction. In the plate 31, four pressure chamber arrays 39 arranged in the scanning direction are formed.
In the plate 32, a plurality of through holes 42 having a substantially circular shape is formed in a part overlapping a right end portion of the plurality of pressure chambers 40. In the plate 32, a plurality of through holes 43 having a substantially circular shape is formed in a part overlapping a left end portion of the plurality of pressure chambers 40.
In the plate 33, four manifold channels 41 are formed. The four manifold channels 41 correspond to the four pressure chamber arrays 39. Each manifold channel 41 extends in the conveyance direction across the plurality of pressure chambers 40 forming the corresponding pressure chamber array 39, and overlaps a substantially right half of these pressure chambers 40. Ink is supplied to each manifold channel 41 through an ink supply port 38 formed in an upstream end portion in the conveyance direction. In the plate 33, a plurality of through holes 44 having a substantially circular shape is formed in a part overlapping the plurality of through holes 43.
In the plate 34, a plurality of nozzles 45 is formed in a part overlapping the plurality of through holes 44. The plurality of nozzles 45 is opened in a lower surface of the plate 34 that is the nozzle surface 3a. The plurality of nozzles 45 forms nozzle arrays 37 by being arranged in the conveyance direction similarly to the plurality of pressure chambers 40. In the plate 34, four nozzle arrays 37 arranged in the scanning direction are formed. Ink of black, yellow, cyan, and magenta is ejected from the plurality of nozzles 45 in this order from the nozzle array 37 at the right end.
<Piezoelectric Actuator>
The piezoelectric actuator 22 has a vibration plate 51, a piezoelectric layer 52, a common electrode 53, and a plurality of individual electrodes 54. The vibration plate 51 is formed of a piezoelectric material having lead zirconate titanate that is a mixed crystal of lead titanate and lead zirconate, as a main component. The vibration plate 51 is arranged on an upper surface of the channel unit 21 (upper surface of the plate 31). However, the vibration plate 51 may be formed of an insulating material other than the piezoelectric layer, such as a synthetic resin material, unlike the piezoelectric layer 52 described below.
The piezoelectric layer 52 is formed of a piezoelectric material and extends continuously across the plurality of pressure chambers 40 on an upper surface of the vibration plate 51. The common electrode 53 extends continuously across the plurality of pressure chambers 40 between the vibration plate 51 and the piezoelectric layer 52. The common electrode 53 is always kept at a ground potential.
The plurality of individual electrodes 54 is individually provided for the plurality of pressure chambers 40. Each individual electrode 54 has a substantially elliptical shape that is smaller than the pressure chambers 40 in a plan view. Each individual electrode 54 is arranged on the top surface of the piezoelectric layer 52 so as to overlap a center part of the corresponding pressure chamber 40. A right end portion of each individual electrode 54 extends to a right side up to a position not overlapping the pressure chamber 40 and its tip end portion is a connection terminal 54a. Bumps 55 formed of a conductive material and protruding upward are arranged on an upper surface of the connection terminal 54a. One of a ground potential and a particular driving potential V is selectively applied individually to the plurality of individual electrodes 54, by a driver IC 62 described later.
In the piezoelectric actuator 22 having the above-described configuration, the common electrode 53 and the plurality of individual electrodes 54 are arranged in this way. In connection to this arrangement, a part sandwiched by each individual electrode 54 of the piezoelectric layer 52 and the common electrode 53 are polarized in a thickness direction. Each part overlapping each pressure chamber 40 of the piezoelectric actuator 22 serves as a drive element 50 for ejecting ink from the corresponding nozzle 45.
A method for driving the piezoelectric actuator 22 (the plurality of drive elements 50) to eject ink from the nozzles 45 will be described. In the piezoelectric actuator 22, all individual electrodes 54 are kept at the ground potential preliminarily by the driver IC 62. In order to eject ink from a certain nozzle 45, the potential of the individual electrode 54 that corresponds to the nozzles 45 is switched from the ground potential to the driving potential by the driver IC 62. Then, due to the potential difference between the individual electrode 54 and the common electrode 53, an electric field in a polarization direction is generated in a part of the piezoelectric layer 52 sandwiched by these electrodes, and the part of the piezoelectric layer 52 is contracted in a surface direction perpendicular to the polarizing direction. Thereby, a part of the vibration plate 51 and the piezoelectric layer 52 overlapping the pressure chamber 40 is deformed to be convex toward the pressure chamber 40 as a whole. As a result, the volume of the pressure chamber 40 decreases, and thereby the pressure of ink in the pressure chamber 40 is increased and ink is ejected from the nozzle 45 communicating with the pressure chamber 40.
<COF>
A COF (chip on film) 61 is arranged above the piezoelectric actuator 22. The COF 61 is connected to the plurality of bumps 55. The COF 61 extends to the right side from connection with the plurality of bumps 55 and is bent upward. The driver IC 62 (an example of a heat generator) is mounted on a part of the COF 61 extending vertically. The driver IC 62 is connected to the plurality of individual electrodes 54 via a wiring (not shown) that is formed in the COF 61 and via the bumps 55.
<FPC>
A FPC (flexible printed circuit) 63 is connected to an upper end portion of the COF 61. The FPC 63 extends upward from connection with the COF 61. An end portion of the FPC 63 opposite the COF 61 is connected to a board (not shown) that is connected to a controller 70. A thermistor 65 (an example of a temperature sensor) is arranged at a middle portion of the FPC 63. The thermistor 65 is for detecting temperature of the inkjet head 3.
The inkjet head 3, the driver IC 62, and the thermistor 65 are connected to each other by a wiring member 64 that includes the COF 61 and the FPC 63. The inkjet head 3, the driver IC 62, and the thermistor 65 are arranged as described above. Thus, in a direction in which the wiring member 64 extends, the thermistor 65 is located at the opposite side from the inkjet head 3 with respect to the driver IC 62. As shown in
<Controller>
The controller 70 controls operations of the printer 1. As shown in
<Operation of Printer at the Time of Printing>
Next, operation of the printer at the time of printing will be described.
After the medium sensor 6 detects the leading end of the recording sheet P, the printer 1 performs printing on the recording sheet P by alternately repeating scan printing and conveying of the recording sheet P. In the scan printing, while the carriage 2 is moved in the scanning direction, ink is ejected from the plurality of nozzles 45 of the inkjet head 3. In the conveying of the recording sheet P, the recording sheet P is conveyed in the conveyance direction by the conveying rollers 4a, 4b. The printer 1 can selectively perform one of bidirectional printing and unidirectional printing. In the bidirectional printing, the plurality of nozzles 45 ejects ink in both when the carriage 2 is moved to the right side and when the carriage 2 is moved to the left side. In the unidirectional printing, the plurality of nozzles 45 ejects ink only when the carriage 2 is moved to the right side or the left side.
<Printing of Test Pattern>
Next, the procedure of printing test patterns for making various adjustments in the printer 1 will be described. For example, at the time of manufacturing the printer 1, a test pattern is printed and adjustments are made based on the print result of the test pattern, as described below. Specifically, when a user operates an operating device (not shown) of the printer 1 or a PC connected to the printer 1 based on the print result of the test pattern, the controller 70 performs adjustments in response to the operation by the user. Or, in a case where the printer 1 is a multifunction peripheral having a scanner and so on, the controller 70 may perform adjustments based on a reading result of the scanner when the test pattern is read by the scanner.
As shown in
As shown in
The plurality of second portions 102 is located at the same position as the plurality of first portions 101 in the scanning direction. The plurality of second portions 102 is arranged in the scanning direction. Each second portion 102 is formed by two rectangular portions 102a. Each of the two rectangular portions 102a is a portion of substantially a rectangular shape having a length K2 in the conveyance direction. The two rectangular portions 102a are arranged with an interval therebetween in the conveyance direction. The interval between the two rectangular portions 102a in the conveyance direction is K1. Among the plurality of second portions 102, the positions of the rectangular portions 102a in the conveyance direction are shifted from each other. Specifically, among the plurality of second portions 102, the rectangular portions 102a of the second portion 102 at the right side in the scanning direction are located at the downstream side in the conveyance direction. That is, the farther right side the second portion 102 is, the farther downstream side the second portion 102 is.
In order to print the conveyance-amount adjusting pattern 100, first, the plurality of first portions 101 is printed by scan printing. Subsequently, after the recording sheet P is conveyed a particular distance by the conveying rollers 4a, 4b, the second portion 102 corresponding to the leftmost first portion 101 is printed by scan printing. Subsequently, after the recording sheet P is conveyed a small distance by the conveying rollers 4a, 4b, the second portion 102 corresponding to the second first portion 101 from the left is printed by scan printing. Likewise, by repeating conveyance of the recording sheet P by a small distance and scan printing, the second portion 102 corresponding to each first portion 101 is printed. By this operation, the conveyance-amount adjusting pattern 100 is printed in which a plurality of sets 103 of the first portion 101 and the second portion 102 is arranged in the scanning direction.
The conveyance-amount adjusting pattern 100 allows selecting, from among the plurality of sets 103, one set 103 having two rectangular portions 101a and two rectangular portions 102a arranged alternately in the conveyance direction without overlapping, that is, one set 103 having no white streak 104 where ink does not land, between any rectangular portion 101a and rectangular portion 102b (the third set 103 from the left in the example of
Returning to
In the non-ejection-nozzle checking pattern 110, for example, among the plurality of portions 111, the portion 111 corresponding to a non-ejection nozzle that ejects no ink (for example, the portion 111 shown by the dashed lines in
Returning to
As shown in
In order to adjust the threshold of the medium sensor 6 by using the medium-sensor adjusting pattern 120, the recording sheet P on which the medium-sensor adjusting pattern 120 is printed is set again in the printer 1. After the medium sensor 6 detects the leading end of this recording sheet P and the recording sheet P is conveyed by the above particular amount, the medium sensor 6 is controlled to detect whether the recording sheet P exists while moving the carriage 2 in the scanning direction. At this time, if the set threshold is appropriate, the recording sheet P is not detected when the medium sensor 6 faces the portions 121 at both end portions of the recording sheet P in the scanning direction, and the recording sheet P is detected when the medium sensor 6 faces a center portion of the recording sheet P in the scanning direction where the portions 121 are not printed. In this case, adjustments of the threshold are unnecessary.
On the other hand, if the threshold is too low, the recording sheet P is always detected regardless of whether the medium sensor 6 faces the portion 121. In this case, the threshold is increased. In contrast, if the threshold is too high, the recording sheet P is not detected at all regardless of whether the medium sensor 6 faces the portion 121. In this case, the threshold is decreased.
The sequence of printing the above three patterns 100, 110, and 120 is not limited to the sequence described above. For example, the three patterns 100, 110, and 120 may be printed in a sequence different from the one described above, such as printing in the sequence of the patterns 110, 100, and 120. In the present embodiment, each of the patterns 100, 110, and 120 is an example of “another pattern”. The operation for printing the pattern 100, 110, 120 is an example of “preparing operation”, and the processing of the controller 70 for performing this operation is an example of “preparing process”.
When the drive elements 50 are driven by the driver IC 62, the driver IC 62 generates heat, heat of the driver IC 62 is transmitted to the inkjet head 3 and the thermistor 65 via the wiring member 64, and a thermistor temperature Ts and a temperature of the inkjet head 3 (hereinafter referred to as “head temperature Th”) increase. As shown in
In the embodiment, since the thermistor 65 is located at the opposite side from the inkjet head 3 with respect to the driver IC 62, the ways in which heat is transmitted from the driver IC 62 to the inkjet head 3 and to the thermistor 65 are different. The length L1 of the portion of the wiring member 64 from the thermistor 65 to the driver IC 62 is longer than the length L2 of the portion from the inkjet head 3 to the driver IC 62. Thus, transmission of heat from the driver IC 62 to the thermistor 65 takes longer time than transmission from the driver IC 62 to the inkjet head 3.
From these, as shown in
In the present embodiment, as described above, while the three patterns 100, 110, and 120 are printed, the temperatures of the inkjet head 3 and the thermistor 65 rises and the state changes from the second state to the first state. When printing of the three patterns 100, 110, and 120 is completed, the controller 70 determines that the printer 1 has become the first state (an example of a determining process), and subsequently prints an ejection-timing adjusting pattern (droplet-landing-position adjusting pattern) 130 (S104).
As shown in
The plurality of second portions 132 is located at the same position as the plurality of first portions 131 in the conveyance direction. The plurality of second portions 132 is arranged in the conveyance direction. Each second portion 132 is formed by two rectangular portions 132a. Each of the two rectangular portions 132a is a portion of substantially a rectangular shape having a length E2 in the scanning direction. The two rectangular portions 132a are arranged with an interval therebetween in the scanning direction. The interval between the two rectangular portions 132a in the scanning direction is E1. Among the plurality of second portions 132, the positions of the rectangular portions 132a in the scanning direction are shifted from each other. Specifically, the rectangular portions 132a of the second portion 132 at the downstream side in the conveyance direction are located at the right side in the scanning direction. That is, the farther downstream side the second portion 132 is, the farther right side the second portion 132 is.
In order to print the ejection-timing adjusting pattern 130, first, one first portion 131 is printed by scan printing in which the carriage 2 is moved to the right side. Subsequently, without conveying the recording sheet P, one second portion 132 is printed by scan printing in which the carriage 2 is moved to the left side. By this operation, a set 133 of the first portion 131 and the second portion 132 corresponding to each other is printed.
Subsequently, after the recording sheet P is conveyed by the conveying rollers 4a, 4b, the first portion 131 and the second portion 132 are printed as described above. And, a similar operation is repeated. By this operation, the ejection-timing adjusting pattern 130 is printed in which the sets 133 of the first portion 131 and the second portion 132 are arranged in the conveyance direction. Note that, when the ejection-timing adjusting pattern 130 is printed as described above, ejection timing for printing the second portion 132 at the downstream side in the conveyance direction is advanced such that the rectangular portion 132a of the second portion 132 at the downstream side in the conveyance direction is printed at the right side.
The ejection-timing adjusting pattern 130 allows selecting, from among the plurality of sets 133, one set 133 having the rectangular portion 131a and the rectangular portion 132a arranged alternately in the scanning direction without overlapping, that is, one set 133 having no white streak 134 where ink does not land, between any rectangular portion 131a and rectangular portion 132a (the third set 133 from the upstream side in the conveyance direction in the example of
Returning to
The pattern 140a has four portions 141a to 144a. The portion 141a is a filled portion that is formed by large droplets ejected from the nozzles 45 located at a center portion in the conveyance direction, out of the plurality of nozzles 45. The portion 142a is adjacent to the upstream side of the portion 141a in the conveyance direction. The portion 142a is a filled portion that is formed by large droplets ejected from all the nozzles 45. The portion 143a is adjacent to the upstream side of the portion 142a in the conveyance direction. The portion 143a is a filled portion that is formed by large droplets ejected from all the nozzles 45, like the portion 142a. The portion 144a is adjacent to the upstream side of the portion 143a in the conveyance direction. The portion 144a is a filled portion that is formed by large droplets ejected from the nozzles 45 located at the center portion in the conveyance direction, out of the plurality of nozzles 45.
The pattern 140b has four portions 141b to 144b. The portions 141b to 144b are located at the same positions as the portions 141a to 144a, respectively, in the conveyance direction. The portions 141b to 144b are filled portions that are formed by medium droplets ejected from the same nozzles 45 as used for printing the portions 141a to 144a, respectively.
The pattern 140c has four portions 141c to 144c. The portions 141c to 144c are located at the same positions as the portions 141a to 144a, respectively, in the conveyance direction. The portions 141c to 144c are filled portions that are formed by small droplets ejected from the same nozzles 45 as used for printing the portions 141a to 144a, respectively.
In order to print the ejection-amount adjusting pattern 140, first, the portions 141a to 141c are printed by scan printing, by ejecting ink from the nozzles 45 located at the center portion in the conveyance direction, out of the plurality of nozzles 45. Subsequently, after the recording sheet P is conveyed until the nozzle 45 at the farthest downstream side in the conveyance direction becomes adjacent to upstream ends of the portions 141a to 141c, the portions 142a to 142c are printed by scan printing by ejecting ink from all the nozzles 45. Subsequently, after the recording sheet P is conveyed in the conveyance direction by the length of the nozzle array 37, ink is ejected from all the nozzles 45 to print the portions 143a to 143c by scan printing. Subsequently, after the recording sheet P is conveyed until the nozzle 45 at the farthest downstream side in the conveyance direction, out of the nozzles 45 to be used for printing the portions 144a to 144c, becomes adjacent to upstream ends of the portions 143a to 143c, the portions 144a to 144c are printed by scan printing by ejecting ink from the nozzles 45 located at the center portion in the conveyance direction, out of the plurality of nozzles 45.
In the pattern 140a, the portion 141a formed by the nozzles 45 located at the center portion in the conveyance direction and the downstream end of the portion 142a formed by the nozzles 45 at the downstream side in the conveyance direction are juxtaposed in the conveyance direction. Further, in the pattern 140a, the portion 144a formed by the nozzles 45 located at the center portion in the conveyance direction and the upstream end of the portion 143a formed by the nozzles 45 at the upstream side in the conveyance direction are juxtaposed in the conveyance direction. Thus, in the pattern 140a, it is determined whether there is a large variation (difference) of density at a boundary between the portion 141a and the portion 142a and at a boundary between the portion 143a and the portion 144a. If there is a large variation of density at the boundary between the portion 141a and the portion 142a, the ejection amount of ink from the nozzles 45 at the downstream side is adjusted. If there is a large variation of density at the boundary between the portion 143a and the portion 144a, the ejection amount of ink from the nozzles 45 at the upstream side is adjusted. Adjustments of the ejection amount of ink are performed by adjusting driving potentials or driving waveforms for driving the drive elements 50, for example. Similar processes are performed for the patterns 140b and 140c.
Here, in the inkjet head 3, there is a case where the ink ejection amount of the nozzles 45 located at an outer side (upstream and downstream sides) in the conveyance direction is different from the ink ejection amount of the nozzles 45 located at the center in the conveyance direction. Hence, in the present embodiment, the ejection-amount adjusting pattern 140 is printed as described above and, as necessary, the ink ejection amount from the nozzles 45 at the upstream side or the downstream side is adjusted. As described above, normally, it is in the first state when printing is performed in the printer 1. From the print result of the ejection-amount adjusting pattern 140, the ejection amount of ink from the nozzles 45 in the first state is adjusted.
In the present embodiment, each of the patterns 130 and 140 is an example of a related-information acquisition pattern, and the information acquired from the pattern 130, 140 is an example of related information. Further, the process of the controller 70 for printing the pattern 130, 140 is an example of a pattern printing process.
In the present embodiment, each of the patterns 100, 110, 120, 130, and 140 is an example of a test pattern.
In scan printing, the driver IC 62 drives the plurality of drive elements 50 by the driving potential and driving waveform based on the thermistor temperature Ts. Assuming that the thermistor temperature Ts is the same, the head temperature Th is different between the first state and the second state. On the other hand, as the head temperature Th is higher, viscosity of ink in the inkjet head 3 is lower and the ink ejection speed from the nozzles 45 is higher when the drive elements 50 are driven in the same manner.
Based on these, the ink ejection speed from the nozzles 45 at the time of driving the drive elements 50 based on a certain thermistor temperature Ts in the second state is different from the ink ejection speed at the time of driving the drive elements 50 based on the same thermistor temperature Ts in the first state. Accordingly, the droplet landing positions of ink at the time of performing scan printing in the second state are deviated in the scanning direction from the droplet landing positions of ink at the time of performing scan printing in the first state. Hence, unlike the present embodiment, if the ejection-timing adjusting pattern 130 is printed in the second state and the ejection timing in bidirectional printing is adjusted based on that print result, the ejection timing in bidirectional printing in the first state cannot be adjusted appropriately.
Hence, in the present embodiment, as described above, after the state of the printer 1 is changed from the second state to the first state by printing the patterns 100, 110, and 120, the ejection-timing adjusting pattern 130 is printed. Thus, based on the print result of the ejection-timing adjusting pattern 130, the ejection timing in bidirectional printing in the first state can be determined appropriately.
In scan printing, the driver IC 62 drives the plurality of drive elements 50 by the driving potential and driving waveform determined based on the thermistor temperature Ts. Assuming that the thermistor temperature Ts is the same, the head temperature Th is different between the first state and the second state. On the other hand, as the head temperature Th is higher, viscosity of ink in the inkjet head 3 is lower and the ink ejection amount from the nozzles 45 is larger when the drive elements 50 are driven in the same manner.
Based on these, the ink ejection amount from the nozzles 45 at the time of driving the drive elements 50 based on a certain thermistor temperature Ts in the second state is different from the ink ejection amount at the time of driving the drive elements 50 based on the same thermistor temperature Ts in the first state. Accordingly, density of a printed image at the time of performing scan printing in the second state is different from density of a printed image at the time of performing scan printing in the first state. Hence, unlike the present embodiment, if the ejection-amount adjusting pattern 140 is printed in the second state and the ejection amount from the nozzles 45 is adjusted based on that print result, the ejection amount in the first state cannot be adjusted appropriately.
Hence, in the present embodiment, as described above, after the state of the printer 1 is changed from the second state to the first state by printing the patterns 100, 110, and 120, the ejection-amount adjusting pattern 140 is printed. Thus, based on the print result of the ejection-amount adjusting pattern 140, the ejection amount in the first state can be adjusted appropriately.
The positions of the rectangular portions 101a and 102a at the time of printing the conveyance-amount adjusting pattern 100 in the second state are deviated in the scanning direction from the positions of the rectangular portions 101a and 102a at the time of printing the conveyance-amount adjusting pattern 100 in the first state. However, even if the positions of the rectangular portions 101a and 102a are deviated in the scanning direction, the positional relationship between the first portion 101 and the second portion 102 in the conveyance direction does not change. Hence, the set 103 to be selected in the case of printing the conveyance-amount adjusting pattern 100 in the second state is the same as the set 103 to be selected in the case of printing the conveyance-amount adjusting pattern 100 in the first state. Accordingly, there is no problem even if the conveyance-amount adjusting pattern 100 is printed in the second state.
Further, the position of each portion 111 at the time of printing the non-ejection-nozzle checking pattern 110 in the second state is deviated in the scanning direction from the position of the corresponding portion 111 at the time of printing the non-ejection-nozzle checking pattern 110 in the first state. However, even if the position of each portion 111 is deviated in the scanning direction, it is unchanged whether each portion 111 is printed in the non-ejection-nozzle checking pattern 110. Accordingly, there is no problem even if the non-ejection-nozzle checking pattern 110 is printed in the second state.
Further, the position of each portion 121 at the time of printing the medium-sensor adjusting pattern 120 in the second state is deviated in the scanning direction from the position of the corresponding portion 121 at the time of printing the medium-sensor adjusting pattern 120 in the first state. However, even if the position of each portion 121 is deviated in the scanning direction, there is no change in a result that, assuming that the threshold of the medium sensor 6 is appropriate, the recording sheet P is not detected when the medium sensor 6 faces both end portions of the recording sheet P in the scanning direction, and the recording sheet P is detected when the medium sensor 6 faces the center portion of the recording sheet P in the scanning direction. Further, the density of each portion 121 at the time of printing the medium-sensor adjusting pattern 120 in the second state is slightly different from the density of the portion 121 at the time of printing the medium-sensor adjusting pattern 120 in the first state. However, the threshold is set to a value that is sufficiently larger than luminance acquired when the medium sensor 6 faces the portion 121. Accordingly, even if the density of the portion 121 is changed to some degree, there is no change in a determination result of whether the threshold needs to be adjusted. Based on the above, there is no problem even if the medium-sensor adjusting pattern 120 is printed in the second state.
While the disclosure has been described in detail with reference to the above aspects thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the claims.
In the above-described embodiment, after the three patterns 100, 110, and 120 are printed, the ejection-timing adjusting pattern 130 and the ejection-amount adjusting pattern 140 are printed. However, printing of the patterns is not limited to this. After the three patterns 100, 110, and 120 are printed, only one of the ejection-timing adjusting pattern 130 and the ejection-amount adjusting pattern 140 may be printed. In this case, the printed pattern 130 or 140 is an example of the related-information acquisition pattern, and the information acquired from the printed pattern 130 or 140 is an example of the related information.
Further, after the three patterns 100, 110, and 120 are printed, the printer 1 may print a related-information acquisition pattern other than the patterns 130, 140 for acquiring related information relating to the ejection amount or droplet landing position of ink ejected from nozzles in scan printing.
In the above-described embodiment, after the three patterns 100, 110, and 120 are printed, the ejection-timing adjusting pattern 130 and the ejection-amount adjusting pattern 140 are printed. However, printing of the patterns is not limited to this. For example, if the state can be changed from the second state to the first state by printing a part of the three patterns 100, 110, and 120, the ejection-timing adjusting pattern 130 and the ejection-amount adjusting pattern 140 may be printed after printing the part of the three patterns 100, 110, and 120. In this case, after the ejection-timing adjusting pattern 130 and the ejection-amount adjusting pattern 140 are printed, remaining one(s) of the three patterns 100, 110, and 120 may be printed. In this case, the operation of printing the part of the three patterns 100, 110, and 120 is an example of a preparing operation, and the process of the controller 70 for performing this operation is an example of a preparing process.
Further, the test pattern printed before printing the ejection-timing adjusting pattern 130 is not limited to the patterns 100, 110, and 120. Before printing the ejection-timing adjusting pattern 130 and the ejection-amount adjusting pattern 140, the printer 1 may print such a test pattern (other than the patterns 100, 110, and 120) that information to be acquired is not changed by differences of the ink ejection amount and the droplet landing position in the scanning direction between printing in the first state and printing in the second state. In this case, the operation of printing the other test pattern is an example of the preparing operation, and the process of the controller 70 for performing this operation is an example of the preparing process.
In the above-described embodiment, the medium-sensor adjusting pattern 120 shown in
In the above-described embodiment, the state is changed from the second state to the first state by causing the driver IC 62 to generate heat by printing another test pattern before printing the ejection-timing adjusting pattern. The operation for changing the state is not limited to this. For example, the state may be changed from the second state to the first state by causing the driver IC 62 to generate heat by driving the plurality of drive elements 50 to a degree that ink is not ejected from the nozzles 45. In this case, the operation of driving the plurality of drive elements 50 to a degree that ink is not ejected from the nozzles 45 is an example of the preparing operation, and the process of the controller 70 for performing this operation is an example of the preparing process.
Alternatively, the state may be changed from the second state to the first state by causing the driver IC 62 to generate heat by moving the carriage 2 to a position at which the plurality of nozzles 45 faces a nozzle cap (not shown) or an ink foam and, in this state, driving the plurality of drive elements 50 by the driver IC 62 to eject ink from the plurality of nozzles 45. In this case, the operation of driving the plurality of drive elements 50 to eject ink from the plurality of nozzles 45 is an example of the preparing operation, and the process of the controller 70 for performing this operation is an example of the preparing process.
In the above-described embodiment and modifications, the ejection-timing adjusting pattern is printed after the state is changed from the second state to the first state by driving the plurality of drive elements 50 by the driver IC 62. The method of changing the state is not limited to this. For example, a heater may be provided, and the state may be changed from the second state to the first state by heating the inkjet head 3, the driver IC 62, and the thermistor 65 with this heater to increase the temperature of these components.
In the above-described embodiment, it is determined to be in the first state when the temperature difference ΔT1 between the thermistor temperature Ts and the head temperature Th is constant, and it is determined to be in the second state when the temperature difference ΔT1 varies with time. However, determination of the first state and the second state is not limited to this.
As the above-described embodiment, the state where the temperature difference between the thermistor temperature Ts and the temperature in a part of the inkjet head is substantially constant (varies only in a range of ±1 degree Celsius or less) may be determined to be the first state. Alternatively, in a case where there is a temperature difference to some extent between a plurality of parts of the inkjet head, the state where the thermistor temperature becomes substantially equal to an average value of the temperature of the plurality of parts may be determined to be the first state.
For example, in a modification, as shown in
In this case, heat generated by two driver ICs 205 is each transmitted to the inkjet head 203 and to the thermistor 207. In the inkjet head 203, ink flows into the manifold channel 41 (see
In this modification, when the plurality of drive elements 50 (see
In the above-described embodiment, this disclosure is applied to the printer having the inkjet head that eject ink from the nozzles communicating with the pressure chambers by deforming the vibration plate and the piezoelectric layer of the piezoelectric actuator to increase the pressure of ink in the pressure chambers. In this printer, the driver IC driving the piezoelectric actuators serves as a heat generator. However, this disclosure may be applied to another type of printer. For example, this disclosure may be applied to a printer including an inkjet head in which a heater for ejection is individually arranged for an ejection port of ink, as disclosed in Japanese Patent Application Publication No. 2016-43634. In this printer, the heater for ejection generates heat so that ink on the heater bubbles, and ink is ejected from the ejection port. In this case, the heater for ejection serves as a heat generator.
In the above-described embodiment, this disclosure is applied to the inkjet printer including a so-called serial head for printing by ejecting ink from the inkjet head while moving, in the scanning direction, the carriage on which the inkjet head is mounted. However, this disclosure may be applied to an inkjet printer having a so-called line head that is an inkjet head extending over an entire length in a direction perpendicular to the conveyance direction of a recording sheet. In the inkjet printer having the line head, printing is performed by ejecting ink from the line head, while the recording sheet is conveyed. If, in the second state, ink is ejected at the ejection timing determined to be suitable in the first state, the droplet landing position of ink is deviated in the conveyance direction. Therefore, in the inkjet printer having the line head, it is also effective to determine whether it is in the first state or in the second state and, when it is in the second state, to correct the ejection timing or the ejection speed. Alternatively, it is effective to determine whether it is in the first state or in the second state and, when it is in the second state, to correct the temperature detected by the thermistor and to determine the ejection timing or the ejection speed based on the corrected temperature.
Further, this disclosure can be applied to a printer that performs printing by ejecting liquid other than ink, such as a wiring pattern material to be printed on a wiring board.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-176932 | Sep 2016 | JP | national |
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| Number | Date | Country | |
|---|---|---|---|
| 20180072081 A1 | Mar 2018 | US |
