Patent Grant
8100501
1. Field of the Invention
The present invention relates to a liquid ejection apparatus, an image forming apparatus and a liquid ejection method, and more particularly, to a liquid ejection apparatus and a liquid ejection method whereby an ejection liquid can be ejected stably by securing gas barrier properties and preventing aggregation or sedimentation of the coloring material, or the like, contained in the ejection liquid.
2. Description of the Related Art
Japanese Patent Application Publication No. 2005-041048 discloses a liquid spraying apparatus which is mainly constituted of a recording head 222, an ink cartridge 221, a pressure control unit 223, as shown in FIG. 15. The ink cartridge 221 is connected with a pump 238 in the pressure control unit 223 via a pressure control valve 229 by means of a pressure control tube 237. The pressure sensor 236, which is connected with the ink cartridge 221 via the pressure control tube 237, measures an air pressure in the ink cartridge 221.
By means of this composition, it is possible to keep the air pressure in the ink cartridge 221, in which an ink bag 231 is accommodated, to a negative pressure, by means of a control circuit 239 in the pressure control unit 223 controlling the pressure control valve 229 and the pump 238 on the basis of a determination signal from the pressure sensor 236.
However, in Japanese Patent Application Publication No. 2005-041048, the ink bag 231 is composed of a member having plastic properties and gas barrier properties. More specifically, for example, the ink bag is composed of an aluminum laminate film in which an aluminum film is interposed between an outer film (a nylon film) and an inner film (a polyethylene film).
Therefore, the ink bag 231 has a thickness of several 100 μm and has relatively high rigidity, and consequently, local creasing or wrinkling occurs as the ink is consumed. If the local creasing or wrinkling occurs in the ink bag 231, then the convection flow in the ink liquid (i.e., ejection liquid) stagnates in the corresponding portion, and there is a possibility that aggregation or sedimentation of the coloring material, or the like, contained in the ink liquid will occur. If the aggregate or sediment caused by the aggregation or sedimentation of the coloring material, or the like, flows into the recording head during ejection of the ink, then ejection failure will arise.
Another composition is possible in which the ink bag 231 is provided with folds in the form of a three-dimensional folding composition or accordion structure, but in this case also, convection flow of the ink in the region of the fold is prevented, and consequently, aggregated material and sediment of the ink is generated, and this aggregate and sediment is supplied to the recording head, giving rise to pressure loss and blockages of nozzles.
The present invention has been contrived in view of the foregoing circumstances, an object thereof being to provide a liquid ejection apparatus, an image forming apparatus and a liquid ejection method, whereby an ejection liquid can be ejected stably by securing gas barrier properties and preventing aggregation or sedimentation of the coloring material, or the like, contained in the ejection liquid.
In order to attain the aforementioned object, the present invention is directed to a liquid ejection apparatus including: a recording head which includes a nozzle and an ejection device, the ejection device ejecting an ejection liquid through the nozzle by applying pressure to the ejection liquid in the recording head; a liquid accommodation unit which is in connection with the recording head and which accommodates a gas, the ejection liquid to be supplied to the recording head, and a non-volatile liquid having a permeability to the gas lower than the ejection liquid, the ejection liquid being separated from the gas by the non-volatile liquid; and a pressure control unit which controls pressure of the ejection liquid in the liquid accommodation unit by moving the gas into and out of the liquid accommodation unit.
In this aspect of the present invention, since a non-volatile liquid having a lower gas permeability than the liquid for ejection (i.e., ejection liquid) is present between the gas and the liquid for ejection, then it is possible to adjust the pressure while suppressing dissolution of the gas into the liquid for ejection. Furthermore, even in cases where liquid for ejection has been ejected from the recording head and the liquid for ejection inside the liquid accommodation unit has been consumed, no parts which inhibit convection currents arise within the liquid for ejection, and consequently, there is no occurrence of aggregate or sediment of the coloring material, or the like. Therefore, it is possible to achieve a state of stable ejection from the recording head.
Preferably, the non-volatile liquid has a specific gravity less than the ejection liquid.
In this aspect of the present invention, the layer of the non-volatile liquid is formed over the layer of the ejection liquid, and it is possible to achieve a state of separation between the liquid for ejection and the gas, reliably, by means of the non-volatile liquid. It is therefore possible to adjust the pressure while suppressing dissolution of the gas into the liquid for ejection more reliably, and moreover, the occurrence of regions where convection currents are inhibited in the liquid for ejection is prevented, and hence there is no occurrence of aggregate or sediment of the coloring material, or the like. Consequently, it is possible to achieve a state of stable ejection from the recording head.
Preferably, the liquid accommodation unit includes a porous member impregnated with the non-volatile liquid; and the ejection liquid is separated from the gas by the non-volatile liquid held in the porous member.
In this aspect of the present invention, by providing the solid porous member impregnated with the non-volatile liquid, it is possible to prevent the effects of external vibrations and hence to stabilize the pressure of the liquid for ejection inside the liquid accommodation unit. Moreover, by impregnating the solid porous member with the non-volatile liquid, it is possible to prevent the non-volatile liquid from flowing into the recording head, and since there is no shaking of the liquid surface, it is also possible to minimize the remaining amount of the liquid for ejection.
Preferably, the liquid accommodation unit includes an elastic film disposed between the ejection liquid and the non-volatile liquid.
In this aspect of the present invention, the liquid for ejection and the non-volatile liquid are separated by the elastic film, and therefore there are no restrictions on the physical properties (e.g., the specific gravity or the miscibility with respect to the liquid for ejection) of the non-volatile liquid to be used. Consequently, it is also possible to use a relatively inexpensive non-volatile liquid.
Even if the liquid for ejection is used up, the non-volatile liquid never flows into the recording head, and therefore it is possible to use up the liquid for ejection, completely. Moreover, even in cases where the liquid for ejection inside the liquid accommodation unit has been consumed due to ejection of the liquid for ejection from the recording head, no parts which inhibit convection currents arise within the liquid for ejection, and consequently, there is no occurrence of aggregate or sediment of the coloring material, or the like. Furthermore, even if the elastic film has gas permeable properties, it is possible to maintain the deaerated state of the liquid for ejection due to the presence of the non-volatile liquid.
Preferably, the liquid accommodation unit further includes an elastic film disposed between the non-volatile liquid and the gas.
In this aspect of the present invention, since a non-volatile liquid is filled in between the two elastic films, then even if the liquid accommodation unit is large in size, it is possible to reduce the volume of non-volatile liquid, and therefore costs can be lowered.
Preferably, the liquid accommodation unit includes an elastic film supporting member which movably supports the elastic film.
In this aspect of the present invention, the elastic film supporting member and the elastic film move in accordance with the amount of the liquid for ejection, and it is possible to restrict the amount of deformation of the elastic film to a uniform range, during a normal recording operation. It is therefore possible to minimize the non-volatile liquid and to lower costs, and since the elastic film does not maintain a state of great deformation over a long period of time, then the life of the elastic film can be extended.
Here, “during a normal recording operation” means during carrying out the normal recording operations, apart from the initial filling of the liquid for ejection or maintenance operations.
Preferably, the non-volatile liquid has a light transmittance less than the ejection liquid.
Preferably, the non-volatile liquid has a light reflectance greater than the ejection liquid.
In this aspect of the present invention, even if the liquid for ejection is transparent, it is still possible to determine the position of the liquid for ejection, reliably.
In order to attain the aforementioned object, the present invention is also directed to a liquid ejection apparatus including: a recording head which includes a nozzle and an ejection device, the ejection device ejecting an ejection liquid through the nozzle by applying pressure to the ejection liquid in the recording head; a liquid accommodation unit which is in connection with the recording head and which accommodates a gas, the ejection liquid to be supplied to the recording head, and a non-volatile liquid that is a magnetic fluid and has a permeability to the gas lower than the ejection liquid, the ejection liquid being separated from the gas by the non-volatile liquid; a magnetic force generating device which applies a magnetic force to the non-volatile liquid; and a pressure control unit which controls pressure of the ejection liquid in the liquid accommodation unit by adjusting the magnetic force of the magnetic force generating device.
In this aspect of the present invention, it is possible to achieve continuous operation without creating oscillations in the gas of the liquid accommodating unit, and it is possible to achieve more accurate adjustment of the pressure of the liquid for ejection.
In order to attain the aforementioned object, the present invention is also directed to a liquid ejection apparatus including: a recording head which includes a nozzle and an ejection device, the ejection device ejecting an ejection liquid through the nozzle by applying pressure to the ejection liquid in the recording head; a liquid accommodation unit which is in connection with the recording head and which accommodates a gas, the ejection liquid to be supplied to the recording head, and a non-volatile liquid having a permeability to the gas lower than the ejection liquid, the liquid accommodation unit including an inelastic member that separates the ejection liquid from the gas, and an elastic film that separates the non-volatile liquid from the ejection liquid and the gas; and a pressure control unit which controls pressure of the ejection liquid in the liquid accommodation unit by moving the gas into and out of the liquid accommodation unit.
In this aspect of the present invention, a portion of the liquid for ejection makes contact with the non-volatile liquid via the elastic film, and moreover, a portion thereof makes contact with the gas via the non-elastic member. Consequently, even if the liquid accommodation unit is large in size, then it is possible to use only a small amount of non-volatile liquid, and hence costs can be lowered.
In order to attain the aforementioned object, the present invention is also directed to an image forming apparatus including one of the above-described liquid ejection apparatuses.
In order to attain the aforementioned object, the present invention is directed to a liquid ejection method including the steps of: ejecting an ejection liquid from a nozzle of a recording head by applying pressure to the ejection liquid in the recording head; and controlling pressure of the ejection liquid in a liquid accommodation unit which is in connection with the recording head and which accommodates the ejection liquid and a gas by moving the gas into and out of the liquid accommodation unit, while the ejection liquid is supplied from the liquid accommodation unit to the recording head, the ejection liquid in the liquid accommodation unit being separated from the gas by a non-volatile liquid having a permeability to the gas lower than the ejection liquid.
According to the present invention, it is possible to achieve a state of stable ejection of the liquid for ejection, by ensuring gas barrier properties, and preventing aggregation or sedimentation of the coloring material, or the like, which is contained in the liquid for ejection.
The nature of this invention, as well as other objects and advantages thereof, will be explained in the following with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures and wherein:
Description of Liquid Ejection Apparatus and Method
The non-volatile liquid 32 accommodated inside the enclosure 21A of the liquid accommodation unit 21 has properties whereby the non-volatile liquid 32 does not mix with the ejection liquid 31. For example, in a case where the ejection liquid 31 is a water-based ink, a non-aqueous liquid may be used. Since the non-volatile liquid 32 has properties whereby the non-volatile liquid 32 does not mix with the ejection liquid 31, then the ejection liquid 31 and the non-volatile liquid 32 are separated from each other.
Moreover, the non-volatile liquid 32 has a specific gravity less than the ejection liquid 31. Therefore, a layer of the non-volatile liquid 32 is formed on top of the surface of the ejection liquid 31, in the liquid accommodation unit 21.
Moreover, the non-volatile liquid 32 has a relatively low permeability to gas (e.g., air). Specific examples of the non-volatile liquid 32 include a fluorine oil and a polyolefin, and the like. The non-volatile liquid 32 thus suppresses the permeation of air 35.
Furthermore, in order to judge whether or not the residual amount of ejection liquid 31 is insufficient, the liquid detection device 33 for detecting the non-volatile liquid 32 is disposed in the vicinity of the bottom surface of the liquid accommodation unit 21. The liquid detection device 33 includes a sensor that measures a light transmittance or light reflectance and judges the presence of the non-volatile liquid 32 on the basis of the measured light transmittance or light reflectance. By means of this composition, the liquid detection device 33 detects the non-volatile liquid 32 when the level of the non-volatile liquid 32 is lowered to a position corresponding to the liquid detection device 33 as the ejection liquid 31 is consumed. Desirably, the liquid detection device 33 is disposed in a position slightly distanced from the bottom surface of the liquid accommodation unit 21, in order to prevent the non-volatile liquid 32 from flowing into the recording head 22 if the liquid surface is shaken. More specifically, desirably, the liquid detection device 33 is disposed in a position distanced 5 mm to 20 mm from the bottom surface of the liquid accommodation unit 21.
In the liquid ejection apparatus shown in
The non-volatile liquid 32 has a light transmittance lower than the ejection liquid 31, or it has a light reflectance higher than the ejection liquid 31. The liquid detection device 33 is therefore able to detect the non-volatile liquid 32 by measuring the light transmittance or the light reflectance of the non-volatile liquid 32. Therefore, even if the ejection liquid 31 is transparent, it is possible to judge whether or not the ejection liquid 31 is insufficient, reliably and inexpensively. The non-volatile liquid 32 may be, for example, a fluorinated oil or polyolefin mixed with an opaque (white or gray) silicone oil, or a fluorinated oil which contains pigment particles dispersed therein and coated with a fluorine-based polymer to form capsules.
In the liquid ejection apparatus 11 according to the present embodiment which has the above-described composition, the pressure of the ejection liquid 31 in the enclosure 21A of the liquid accommodation unit 21 is controlled to a uniform pressure by means of the pressure adjustment device 23 causing the air 35 to exit from or enter into the enclosure 21A of the liquid accommodation unit 21, and in this controlled pressure state, the ejection liquid 31 in the enclosure 21A of the liquid accommodation unit 21 is supplied via the connection channel 34 to the recording head 22, and the ejection liquid 31 is ejected from the nozzles 151 (shown in not
Moreover, liquid detection devices (33A and 33B) for detecting the non-volatile liquid 32 are disposed in the vicinity of the upper surface and the bottom surface of the liquid accommodation unit 21. The liquid detection device 33A, which is disposed in the vicinity of the upper surface, detects the non-volatile liquid 32 when the level of the non-volatile liquid 32 is heightened, and the liquid detection device 33A judges whether the liquid accommodation unit 21 is full with the ejection liquid 31 and the non-volatile liquid 32 (i.e., whether the non-volatile liquid 32 is about to flow out to the pump 38). On the other hand, the liquid detection device 33B, which is disposed in the vicinity of the lower surface, detects the non-volatile liquid 32 when the level of the non-volatile liquid 32 is lowered, and the liquid detection device 33B judges whether or not the ejection liquid 31 is insufficient, by determining the presence of the non-volatile liquid 32. Desirably, the liquid detection device 33B is disposed in a position slightly distanced from the bottom surface of the liquid accommodation unit 21, in order to prevent the non-volatile liquid 32 from flowing in to the recording head 22 if the liquid surface is shaken. More specifically, desirably, the liquid detection device 33B is disposed in a position distanced 5 mm to 20 mm from the bottom surface of the liquid accommodation unit 21.
According to the embodiment shown in
According to the embodiment shown in
According to the embodiment shown in
Moreover, the liquid detection device 33 for detecting the non-volatile liquid 32 is disposed at a position in the vicinity of the position at which the elastic film 48 is fixed, and preferably, it is disposed at a distance of 0 mm to 5 mm above the fixing position. When the remaining amount of ejection liquid 31 has become low and the level of the non-volatile liquid 32 is lowered, the liquid detection device 33 detects the air 35 (i.e., the absence of the non-volatile liquid 32) and thereby judges whether or not the ejection liquid 31 in the liquid accommodation unit 21 is insufficient.
From the above, according to the embodiment shown in
Furthermore, beneficial effects are obtained in that even when all of the ejection liquid 31 has been used up, the non-volatile liquid 32 does not flow into the recording head 22, and therefore it is possible to use up the ejection liquid 31 completely. Moreover, the elastic film 48 deforms while maintaining a curved surface shape, and therefore a beneficial effect is obtained in that the convection flow in the ejection liquid 31 is not inhibited, and aggregation or sedimentation of the coloring material, or the like, does not occur. Furthermore, even in a case where the elastic film 48 has a relatively high permeability to the gas (e.g., the air 35), the total permeability to the gas is low due to the presence of the non-volatile liquid 32 which has a relatively low permeability to the gas, and therefore a beneficial effect is obtained in that the deaerated state of the ejection liquid 31 can be preserved.
From the above, according to the embodiment shown in
The member used for the inelastic member 49 is constituted of a material having a maximum elongation of 0% to 10%, and is formed to a substantially planar shape. The inelastic member 49 has a small thickness and a low permeability to the gas. More specifically, it has a gas permeability of 10 cm3·mm/m2·24 h·1 atm or lower, and a thickness of 0.5 mm to 5.0 mm. The material of the inelastic member 49 may be a metal such as stainless steel or aluminum, or a member formed by vapor deposition of aluminum onto a fluorine-based resin such as PFA (which is a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene) or polypropylene (PP), or a dual-layer material composed of a PP layer and a PFA layer.
Furthermore, an inelastic member detector 51 is disposed in the vicinity of the center of the bottom surface of the liquid accommodation unit 21. The inelastic member detector 51 is a sensor which measures a light transmittance or light reflectance. When the ejection liquid 31 is consumed and the inelastic member 49 is lowered, the inelastic member detector 51 detects the inelastic member 49 and thereby judges whether or not the ejection liquid 31 in the liquid accommodation unit 21 is insufficient.
From the above, according to the embodiment shown in
Moreover, desirably, the inner walls of the liquid accommodation unit 21 and the supporting member 52 are formed with a round cylindrical shape. This is because, if a round cylindrical shape is adopted, then the force of friction between the inner walls of the liquid accommodation unit 21 and the supporting member 52 is uniform, and therefore good adhesion between the supporting member 52 and the inner walls of the liquid accommodation unit 21 can be ensured readily.
Furthermore, a supporting member detector 53 for detecting the supporting member 52, which is movable up and down, is disposed in the vicinity of the bottom surface of the liquid accommodation unit 21. The supporting member detector 53 is a sensor which measures a light transmittance or light reflectance. When the ejection liquid 31 is consumed and the supporting member 52 is lowered, the supporting member detector 53 detects the supporting member 52 and thereby judges whether or not the ejection liquid 31 in the liquid accommodation unit 21 is insufficient.
From the above, according to the embodiment shown in
Moreover, a liquid detection device 33 for detecting the non-volatile liquid 32 is disposed in a position in the vicinity of the position at which the elastic film 48 is fixed, and preferably, it is disposed at a distance of 0 mm to 5 mm above the fixing position. When the remaining amount of the ejection liquid 31 has reduced and the level of the non-volatile liquid 32 (i.e., magnetic fluid) is accordingly lowered, the liquid detection device 33 detects the air 35, which is present above the non-volatile liquid 32, and judges whether or not the ejection liquid 31 is insufficient. Furthermore, a flow channel 58 which includes a valve 57 is provided above the liquid accommodation unit 21, and the air 35 is supplied to the liquid accommodation unit 21 through the flow channel 58.
On the basis of this composition, in the embodiment shown in
If the pressure is adjusted by means of a pump, then the oscillations of the pump drive action are transmitted to the air 35 inside the liquid accommodation unit 21, and there is a possibility that this will have an adverse effect on the pressure adjustment in the form of noise. However, according to the embodiment shown in
General Composition of Inkjet Recording Apparatus
In
In the case of the configuration in which roll paper is used, a cutter 128 is provided as shown in
In the case of a configuration in which a plurality of types of recording paper can be used, it is preferable that an information recording medium such as a bar code and a wireless tag containing information about the type of paper is attached to the magazine, and by reading the information contained in the information recording medium with a predetermined reading device, the type of paper to be used is automatically determined, and ink-droplet ejection is controlled so that the ink-droplets are ejected in an appropriate manner in accordance with the type of paper.
The recording paper 116 delivered from the paper supply unit 118 retains curl due to having been loaded in the magazine. In order to remove the curl, heat is applied to the recording paper 116 in the decurling unit 120 by a heating drum 130 in the direction opposite to the curl direction in the magazine.
The decurled and cut recording paper 116 is delivered to the suction belt conveyance unit 122. The suction belt conveyance unit 122 has a configuration in which an endless belt 133 is set around rollers 131 and 132 so that the portion of the endless belt 133 facing at least the nozzle face of the print unit 112 forms a plane.
The belt 133 has a width that is greater than the width of the recording paper 116, and a plurality of suction apertures (not shown) are formed on the belt surface. A suction chamber 134 is disposed in a position facing the nozzle surface of the print unit 112 on the interior side of the belt 133, which is set around the rollers 131 and 132, as shown in
The belt 133 is driven in the clockwise direction in
Since ink adheres to the belt 133 when a marginless print job or the like is performed, a belt-cleaning unit 136 is disposed in a predetermined position (a suitable position outside the printing area) on the exterior side of the belt 133.
A heating fan 140 is disposed on the upstream side of the print unit 112 in the conveyance pathway formed by the suction belt conveyance unit 122. The heating fan 140 blows heated air onto the recording paper 116 to heat the recording paper 116 immediately before printing so that the ink deposited on the recording paper 116 dries more easily.
The ink storing and loading unit 114 has ink tanks for storing the inks of the colors corresponding to the respective recording heads 22 (22K, 22C, 22M, and 22Y shown in
A post-drying unit 142 is disposed following the print unit 112. The post-drying unit 142 is a device to dry the printed image surface, and includes a heating fan, for example. It is preferable to avoid contact with the printed surface until the printed ink dries, and a device that blows heated air onto the printed surface is preferable.
A heating/pressurizing unit 144 is disposed following the post-drying unit 142. The heating/pressurizing unit 144 is a device to control the glossiness of the image surface, and the image surface is pressed with a pressure roller 145 having a predetermined uneven surface shape while the image surface is heated, and the uneven shape is transferred to the image surface.
The printed matter generated in this manner is output from the paper output unit 126. The target print (i.e., the result of printing the target image) and the test print are preferably output separately. In the inkjet recording apparatus 1, a sorting device (not shown) is provided for switching the outputting pathways in order to sort the printed matter with the target print and the printed matter with the test print, and to send them to paper output units 126A and 126B, respectively. When the target print and the test print are simultaneously formed in parallel on the same large sheet of paper, the test print portion is cut and separated by a cutter (second cutter) 148. The cutter 148 is disposed directly in front of the paper output unit 126, and is used for cutting the test print portion from the target print portion when a test print has been performed in the blank portion of the target print. The structure of the cutter 148 is the same as the first cutter 128 described above, and has a stationary blade 148A and a round blade 148B.
Description of Print Unit
Next, the print unit 112 including the above-described liquid ejection apparatus is described.
The print determination unit 124 includes sensors 164 (shown in
The recording paper conveyance amount determination sensor (conveyance amount sensor) 165 is a device which measures the conveyance amount in the sub-scanning direction of the recording paper 116, and it comprises photoelectric sensors arranged following a substantially parallel direction with respect to the sub-scanning direction. The amount of conveyance of the recording paper 116 is determined on the basis of the sensor signal obtained from this conveyance amount sensor 165.
The nozzle pitch h in the staggered nozzle arrangement shown in
A plurality of sensors 164 are arranged in a line configuration (a one-dimensional configuration) on the sensor face of the print determination unit 124. The sensor density (sensor pitch) in the sub-scanning direction is the same as the nozzle density of the recording head 22 (1200 sensors per inch), and the reading resolution of the print determination section 124 is 1200 dpi.
The sensor width (reading width) of the print determination unit 124 is set to be broader than the nozzle width (printing width) of the recording head 22. Accordingly, even if relative positional error occurs between the recording head 22 and the print determination unit 124 mounted on the carriage 162 (see
According to this composition, when a prescribed drive voltage is supplied to the heating element 158, a bubble grows in the ink inside the individual flow channel 152, due to the heat generated by the heating element 158, and an ink droplet is ejected from the nozzle 151 by the pressure created by this bubble. After ink ejection, further ink is supplied from the common flow channel 155 to the individual flow channel 152.
Apart from this, it is also possible to use a piezoelectric element as an ejection device. In this case, when the piezoelectric element is caused to deform by applying a drive voltage, the volume of the pressure chamber changes, and therefore ink is ejected from the nozzle due to the resulting pressure change in the chamber.
Description of Control System
The communication interface 70 is an interface unit for receiving image data sent from a host computer 86. A serial interface or a parallel interface may be used as the communication interface 70. A buffer memory (not shown) may be mounted in this portion in order to increase the communication speed.
The image data sent from the host computer 86 is received by the inkjet recording apparatus 10 through the communication interface 70, and is temporarily stored in the image memory 74. The image memory 74 is a storage device for temporarily storing images inputted through the communication interface 70, and data is written and read to and from the image memory 74 through the system controller 72.
The system controller 72 is a control unit for controlling the various sections, such as the communications interface 70, the image memory 74, the motor driver 76, the heater driver 78, and the like. The system controller 72 is constituted by a central processing unit (CPU) and peripheral circuits thereof, and the like, and in addition to controlling communications with the host computer 86 and controlling reading and writing from and to the image memory 74, or the like, it also generates a control signal for controlling the motor 88 of the conveyance system and the heater 89.
The motor driver (drive circuit) 76 drives the motor 88 in accordance with commands from the system controller 72. The heater driver (drive circuit) 78 drives the heater 89 of the post-drying unit 42 or other units in accordance with commands from the system controller 72.
The print controller 80 has a signal processing function for performing various tasks, compensations, and other types of processing for generating print control signals from the image data stored in the image memory 74 in accordance with commands from the system controller 72 so as to supply the generated print control signal (dot data) to the head driver 84. Prescribed signal processing is carried out in the print controller 80, and the ejection amount and the ejection timing of the ink droplets from the recording heads 22 are controlled through the head driver 84, on the basis of the print data. By this means, prescribed dot size and dot positions can be achieved.
The print controller 80 is provided with the image buffer memory 82; and image data, parameters, and other data are temporarily stored in the image buffer memory 82 when image data is processed in the print controller 80.
The head driver 84 generates drive signals for driving the heating elements 158 of the respective colors in the recording heads 22 (see
As stated previously, the print determination unit 124 reads in a test pattern recorded by the recording heads 22, and performs prescribed signal processing, and the like, in order to determine the ink ejection status of the recording heads 22 (the presence/absence of ejection, the dot sizes, dot depositing positions, and the like) (in other words, it determines variations in the respective nozzles 151). The print determination unit 124 supplies the determination results to the print controller 80. According to requirements, the print controller 80 makes various corrections with respect to the recording heads 22 on the basis of information obtained from the print determination unit 124.
The conveyance amount sensor 165 determines the amount of conveyance of the recording paper 137 in the sub-scanning direction, and the sensor signal obtained from the conveyance amount sensor 165 (conveyance amount information) is supplied to the print controller 180.
The liquid ejection apparatus, the image forming apparatus and the liquid ejection method according to the present invention were described in detail above, but the present invention is not limited to these examples, and it is of course possible for improvements or modifications of various kinds to be implemented, within a range which does not deviate from the essence of the present invention.
For example, the liquid ejection apparatus or the liquid ejection method of the present invention may also be applied to an inkjet recording apparatus using a line system, in which printing is carried out by means of a fixed recording head, which has nozzles arranged in the breadthways direction of the recording paper.
It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the invention is to cover all modifications, alternate constructions and equivalents falling within the spirit and scope of the invention as expressed in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-005994 | Jan 2007 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4019188 | Hochberg et al. | Apr 1977 | A |
| 7874656 | Ota et al. | Jan 2011 | B2 |
| Number | Date | Country |
|---|---|---|
| 2003-226025 | Aug 2003 | JP |
| 2005-41048 | Feb 2005 | JP |
| 2006-326855 | Dec 2006 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20080170098 A1 | Jul 2008 | US |
