JP2012171113A - Ink jet head, droplet discharge device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable good ink jet reducing channel variation and image formation reducing variation of injection characteristics and having good printing quality, and to improve handling performance of a filter plate.SOLUTION: A flow passage substrate 1 is included as a flow passage member, and a plurality of nozzles 4 are formed in a row on a nozzle plate 2 jointed to an upper face of the flow passage substrate 1. By a plate formed by jointing three layers, an ink jet head forms: pressurization liquid chambers 6 formed by individual liquid chambers with which the plurality of nozzles 4 discharging ink droplets are communicated; fluid resistance parts 7 supplying ink to the pressurization liquid chambers 6; and ink introduction parts 8. Ink is supplied from a common liquid chamber 18 formed in a frame member 17 to each pressurization chamber 6 via a filter part 20 of the filter plate 5, the liquid introduction parts 8 and the fluid resistance parts 7. The thickness etc. of a filter part 20 is processed flexibly.

Description

  The present invention relates to an inkjet head, a droplet discharge device using the inkjet head, and an image forming apparatus.

  In an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, an image of a droplet discharge recording method using a recording head composed of a droplet discharge head (liquid discharge head) that discharges ink droplets As a forming apparatus, an ink jet recording apparatus or the like is known. The image forming apparatus of the droplet discharge recording method forms an image by discharging ink droplets from a recording head onto a conveyed paper.

  Conventionally, a droplet discharge head supplies ink carried from a tank to a plurality of individual liquid chambers (pressure chambers) via a common liquid chamber, and is supplied to each individual liquid chamber (pressure chamber). In addition, pressure is selectively applied to the ink using a pressure generating means, and droplets are ejected from the nozzle. If foreign matter such as impurities or contaminants is mixed in the ink in the supply path, the ink is individually It has been regarded as a problem that the liquid chamber is blocked or a discharge failure occurs due to clogging with a nozzle.

  Therefore, in order to prevent contamination of contaminants and other foreign matters, a filter for collecting foreign matters is provided at the supply port to the common liquid chamber in the ink supply path, and further, attempts to avoid problems that occur・ Development has been carried out. Examples of the configuration include Patent Documents 1 to 3. Since the pressure loss of the common ink chamber is small near the ink supply port of the head, the fluid resistance of the common ink chamber decreases, and the pressure loss of the common ink chamber increases as the distance from the ink supply port increases. It is known that the fluid resistance of the chamber is increased.

  In the configuration of Patent Document 1, the linear filter support portion supports the ink intake hole portion of the cavity plate (fixed side mold plate) in which the cavity portion (female portion) is processed. Even if pressure acts on the filter part, the deformation is suppressed, and as a result, the expansion and breakage of small holes in the filter part can be prevented.

  Further, in the configuration of Patent Document 2, since the foreign matter removing property by the filter is higher when the filter is disposed at a position close to the nozzle or the individual liquid chamber, the filter is disposed between the common liquid chamber and the individual flow path (pressure chamber). A filter portion is formed on the diaphragm member interposed between the individual liquid chambers, and a communication portion is formed on the opposite side of the partition wall portion between the individual liquid supply passages from the diaphragm member in order to ensure liquid supply properties to the individual liquid chambers. The plurality of individual liquid supply paths communicate with each other. It has been shown that such a configuration can efficiently remove foreign matters without causing a shortage of liquid supply.

  Further, the configuration of Patent Document 3 is more reliable foreign matter removal, focusing on the position of the filter section described in Patent Document 2 and the flow of ink in the common liquid chamber and its speed. This is intended to avoid the occurrence of defective discharge. Specifically, a supply path forming member (filter) for capturing dust is arranged in the common liquid chamber, and the opening area of the end portion is made smaller than the opening area in the vicinity of the supply port of the supply path forming member. In addition to reducing the opening at the end far from the supply port and increasing the flow rate of the ink flow path, it is shown that the structure is easy to catch foreign matter that tends to collect at both ends due to the manufacturing cleaning mechanism. ing.

  Certainly, in the above-mentioned patent documents 1 to 3, a device for improving the shortage of liquid supply is made. However, in any filter, the aperture ratio, filter diameter, and plate thickness of the filter section are uniform for each channel of the individual liquid chamber, and the increase in fluid resistance in the filter section is also uniform. The uniform fluid resistance in the common liquid chamber from the channel position to the channel position has not been studied at all.

  The difference in fluid resistance for each channel greatly affects the ink ejection characteristics for each channel. Therefore, when ink is ejected in droplets for each channel, not only the fluid resistance in the filter section but also the common The fluid resistance in the ink chamber path should also be taken into account. In other words, considering that there is no variation in the discharge characteristics of each channel is an important factor for good image formation, the improvement in the fluid resistance of the common liquid chamber provides a good inkjet with little channel variation. It is indispensable to do.

  However, with respect to Patent Document 3, since the opening area corresponding to the filter diameter is made small so that the fluid resistance at the end far from the ink supply port located in the center is increased, the fluid in the vicinity from the ink supply port. It is a problem that the difference between the resistance and the fluid resistance at the end far from the inlet is larger. Such a difference is particularly strong in the case of an ejection mode with a large ink flow rate in which an appropriate amount of large droplets are driven at a high frequency.

  In addition, in a filter arranged in the common liquid chamber of the droplet discharge head, an increase in the fluid resistance of the filter section has a large effect on the ink supply performance. Therefore, the fluid resistance is reduced and the pressure loss is minimized. Need to do. Therefore, as a solution to such a problem, it has been considered that the filter portion is made thin in order to reduce an increase in fluid resistance.

  However, by making the filter part thinner, the handleability of the filter plate alone is reduced, and when the nozzle plate, flow path plate, diaphragm, and filter plate are joined together, the filter plate may be bent due to the load during joining. This causes problems such as

  An object of the present invention is to make the ejection characteristics uniform for each channel, and as a result, to provide a good inkjet with little channel variation and to enable good image formation with little ejection property variation and print quality. To do. Furthermore, it is intended to improve the handleability of the filter plate and to improve the yield reduction due to breakage of the filter plate in the head on which the filter plate is mounted.

  In order to achieve this object, an inkjet head according to the present invention includes a nozzle plate having a plurality of nozzles, a flow path substrate having a pressurized liquid chamber corresponding to the nozzles, and a common liquid chamber communicating with the pressurized liquid chamber. And an ink jet head provided with a filter plate provided in a common liquid chamber, the filter plate being disposed over the entire surface of the channel in the nozzle arrangement direction, the thickness varies depending on the distance from the ink supply port, and moves away from the ink supply port. As the fluid resistance becomes smaller, it is characterized.

  According to the present invention, the fluid resistance in the common ink chamber is made uniform between the vicinity of the ink supply port and the position away from the ink supply port, thereby uniformizing the ejection characteristics for each channel, and as a result, the channel variation is excellent. An ink jet can be provided, and an image can be formed with good print quality with little variation in ejection characteristics. Furthermore, it is possible to improve the handleability of the filter plate and improve the yield reduction due to breakage of the filter plate in the head on which the filter plate is mounted.

1 is an exploded perspective view of an inkjet head according to an embodiment of the present invention. It is sectional drawing of the direction orthogonal to the nozzle arrangement direction of the inkjet head which concerns on one Embodiment of this invention. It is sectional drawing of the AA line of FIG. It is the top view which looked at each component of the ink jet head concerning one embodiment of the present invention from the nozzle side. It is the top view which looked at each component of the ink jet head concerning one embodiment of the present invention from the actuator side. It is the figure (zigzag arrangement) which showed the arrangement shape of the filter hole of the ink jet head concerning one embodiment of the present invention. It is the figure (grid arrangement) showing the arrangement shape of the filter hole of the ink jet head concerning one embodiment of the present invention. FIG. 3 is a diagram showing an internal shape of a filter hole showing a transport layout of an inkjet head according to an embodiment of the present invention. 1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. 1 is a plan view of an essential part of an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention.

  Next, an embodiment of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is an exploded perspective view of an inkjet head according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view in a direction orthogonal to the nozzle arrangement direction of the inkjet head according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line AA in FIG.

  The inkjet head has a flow path substrate (restrictor plate) 1 as a flow path member (liquid chamber forming member), and a nozzle plate 2 (orifice plate) bonded to the upper surface of the flow path substrate 1 has a plurality of nozzles. 4 are formed in a row. The vibration plate member 3 joined to the lower surface of the flow path plate 1 is for efficiently transmitting the displacement of the piezoelectric element member 12 to the pressurized liquid chamber 6.

  By means of the three-layer bonded plate, the ink jet head supplies ink to the pressurizing liquid chamber 6, and a plurality of pressurizing liquid chambers 6 formed by individual liquid chambers that communicate with the plurality of nozzles 4 that eject ink droplets. A fluid resistance part 7 to be supplied and an ink introduction part 8 are formed, and from a common liquid chamber 18 which is a common flow path formed in a frame member 17 described later, the filter part 20 of the filter plate 5, the liquid introduction part 8, the fluid Ink is supplied to each pressurized liquid chamber 6 through the resistance portion 7. The filter plate 5 is provided with a filter formed by a large number of small holes in a region facing the common ink chamber 18 of the frame member.

  In the following description, the nozzle plate 3, the flow path substrate 1, the vibration plate 3, and the filter plate 5 are collectively referred to as a flow path unit.

  Here, the flow path plate 1 is formed by, for example, pressing SUS (stainless steel excellent in corrosion resistance) to form openings such as the pressurized liquid chambers 6, the fluid resistance portions 7, and the ink introduction portions 8.

  The nozzle plate 2 forms a nozzle 4 having a diameter of 10 to 30 μm, for example, corresponding to each pressurized liquid chamber 6 and is bonded to the flow path substrate 1 with an adhesive. This nozzle plate 2 is made of a metal such as stainless steel, but other Ni electroforming (a construction method that gives the strength of a cast product by thickly plating nickel), a resin such as a polyimide resin film. , Silicon, and combinations thereof can be used.

  In addition, a volatile treatment layer (not shown) subjected to volatile surface treatment is provided on the nozzle surface (surface in the ejection direction: ejection surface) to ensure water repellency with ink. As the volatile treatment layer, the physical properties of the recording liquid can be obtained by plating coating, fluororesin electrodeposition coating, evaporative fluororesin deposition coating, or baking after solvent coating of silicon resin / fluorine resin. A high-quality image quality is obtained by providing a volatile treatment film according to the above and stabilizing the droplet shape and flight characteristics of the recording liquid.

  The diaphragm member 3 is formed by, for example, Ni electroforming, with a first layer 3a constituting a diaphragm region 3A that forms a part of the wall surface of the pressurized liquid chamber 6, and a second layer 3b that is a thick part. Has been.

  A piezoelectric actuator 11 that deforms and displaces the diaphragm region 3A is provided outside the surface of the diaphragm region 3A of the diaphragm member 3 (on the side opposite to the pressurized liquid chamber 6). The piezoelectric actuator 11 has a configuration in which a piezoelectric element member 12 in which a plurality of piezoelectric element columns 12 a are formed is bonded on a base substrate 13.

  The piezoelectric element member 12 is formed by bonding and fixing to the base substrate 13 and forming grooves that are not divided by groove processing (slit processing), thereby forming a plurality of piezoelectric element columns 12a. 12 is a laminated piezoelectric element in which zirconate titanate (PZT) having a thickness of 10 to 50 μm / layer and internal electrodes made of silver / palladium (AgPd) having a thickness of several μm / layer are alternately laminated. Is used. Further, a flexible wiring board 16 such as an FPC that gives a drive signal is connected to the piezoelectric element column of the piezoelectric actuator 11.

  The processing accuracy of the opening shapes of the nozzle 4 and the pressurized liquid chamber 6 greatly affects the ink discharge characteristics of the inkjet head. In order to suppress these channel accuracy variations among a plurality of channels, the manufacturing method of the flow path substrate 1 requires high processing accuracy. For this reason, the flow path substrate 1 is formed by a stainless precision pressing method. Since the precision press is not affected by expansion and contraction due to heat, it is possible to form each channel with high positional accuracy as compared with other processing methods such as electroforming and metal etching.

  Further, the thickness of the filter plate 5 of the flow path unit 22 is desirably 2 to 10 μm in order to efficiently transmit the displacement of the piezoelectric element member 12. A 2 to 10 μm thin diaphragm is formed by etching or electroforming.

  The frame member 17 has a piezoelectric actuator insertion opening 24 and a common liquid chamber 18 formed therein. The frame member 17 is manufactured by cutting a stainless material or molding a resin material, and an ink introduction portion 19 that guides ink from an ink tank (not shown) to the common liquid chamber 18 is joined. In FIG. 1, the piezoelectric actuator insertion opening 22 of the frame member 17 is greatly opened, but the rigidity is increased by opening each piezoelectric element member 12 so as to have a partition, and mutual interference when a plurality of channels are driven. A structure that can reduce so-called crosstalk may be employed.

  The piezoelectric actuator 11 includes a plurality of piezoelectric element members 12 and a base substrate 13 on which conductor patterning for fixing the piezoelectric element members 12 is performed. The piezoelectric element member 12 is disposed so as to correspond to the diaphragm 3, and one end surface of the piezoelectric element member 12 is bonded to the diaphragm 3. Guide holes for positioning are arranged at both ends of the flow path unit and the base substrate 13 of the piezoelectric actuator 11. In the joining assembly of the flow path unit and the piezoelectric actuator 11, precision processing is performed, and the precision assembly is performed by temporarily connecting and bonding with a positioning pin. On the base substrate 13, individual electrodes and a common electrode for sending an electric signal independent from an external drive circuit to each piezoelectric element member 12 are formed. By these electrodes, a selective electrical signal is applied to the piezoelectric element member 12 from the external drive circuit, and the piezoelectric element member 12 is distorted.

  The principle that the ink jet head discharges ink from the nozzle 4 is as described above, and it is used in an apparatus for forming an ink image on a recording medium. In addition, in order to eject micro droplets for high-quality printing, the inkjet head has a high accuracy and high density in the shape of each flow path and a hole shape of several tens of μm on a plate having a thickness of 40 to 100 μm. Need to be processed.

  Further, a frame member 17 surrounding the piezoelectric actuator 11 is joined to the periphery of the diaphragm member 3 with an adhesive. A common liquid chamber 18 is formed in the frame member 17. Ink is supplied to the common liquid chamber 18 from the outside through an ink supply port 19. The common liquid chamber 18 communicates with the ink introducing portion 8, the fluid resistance portion 7, and the pressurized liquid chamber 6 through a filter portion 20 provided on the filter plate 5.

  Here, an ink extraction method for an inkjet head according to the present invention, to which the characteristic that the piezoelectric element member 12 can be subtly expanded and contracted by controlling the voltage, will be described.

  In such an ink jet head, for example, by lowering the voltage applied to the piezoelectric element column 12a of the piezoelectric element member 12 from the reference potential, the piezoelectric element column 12a contracts, and the diaphragm region 3a of the diaphragm member 3 deforms and pressurizes. As the volume of the liquid chamber 6 expands, ink flows into the pressurized liquid chamber 6, and then the voltage applied to the piezoelectric element columns 12a is increased to extend the piezoelectric element columns 12a in the stacking direction, thereby vibrating the diaphragm region 3a. Is deformed in the direction of the nozzle 4 to shrink the volume and volume of the pressurized liquid chamber 6, whereby the ink in the pressurized liquid chamber 6 is pressurized and ink droplets are ejected from the nozzle 4.

  Then, by returning the voltage applied to the piezoelectric element column 12a to the reference potential, the diaphragm region 3a is restored to the initial position, and the pressurized liquid chamber 6 expands to generate a negative pressure. At this time, the common liquid chamber The pressurized liquid chamber 6 is filled with ink from 18. Therefore, after the vibration of the meniscus surface of the nozzle 4 is attenuated and stabilized, the operation proceeds to the next droplet discharge. Further, the driving method of this head is not limited to the above example (drawing-pushing), and it is also possible to perform striking or pushing depending on the direction to which the drive waveform is given.

  Next, the details of the filter unit 20 in the inkjet head will be described with reference to FIGS.

  3 is a cross-sectional view taken along the line AA of FIG. 2, FIG. 4 is a plan view of each component of the inkjet head viewed from the nozzle side, and FIG. 5 is a plan view of each component of the inkjet head viewed from the actuator side. FIG. The partition 10 of the ink introduction part 8 that communicates with each pressurized liquid chamber 6 provided in the flow path plate 1 is connected to the ink introduction part 8 and the ink introduction part 8 adjacent to each other on the diaphragm member 3 side. The plurality of liquid introduction portions 8 have a configuration in which a part of the recess 10a on the vibration plate member 3 side communicates with each other over the nozzle arrangement direction region as described above. In addition, the filter part 20 is not shielded by the partition wall 10 of the liquid introducing part 8, and the area of the filter part 20 can be secured to prevent the liquid supply performance from being lowered.

  6 and 7 are diagrams showing the detailed arrangement of the filter holes. In the ink jet head according to the present invention, a filter unit 20 for filtering liquid is formed between the common liquid chamber 18 and the ink introduction unit 8 over the entire region in the nozzle arrangement direction. As shown in FIG. 6, the filter section 20 is configured by arranging a plurality of communication holes 20a in a staggered manner, or in a lattice shape as shown in FIG.

  Further, the internal shape (inner side shape) of the communication hole 20a (20b) constituting the filter portion 20 is a tapered shape as shown in FIG. 8 (a) or a horn shape as shown in FIG. 8 (b). The communication hole 20a (20b) has a diameter equal to or smaller than that of the nozzle 4 on the flow path plate 1 side. The taper shape and the horn shape as described above can be easily manufactured by the Ni electroforming method.

  In the arrangement of the filter communication holes, the plate thickness of the filter portion in the communication hole 20a in the vicinity of the ink supply port 19 at both ends of the head is thick. Further, the filter plate thickness at the communication hole 20b at the center of the head is thin. By changing the thickness of the filter portion according to the position from the ink supply port 19, the fluid resistance of the ink supply port 19, the common ink chamber 18 from the ink supply port 19 to the channel position, and the filter portion can be made uniform. it can. Therefore, the pressure loss applied to each channel can be made uniform, and the dispersion of the negative pressure applied to each individual liquid chamber can be reduced for each channel. A head can be provided.

  If the thickness of the filter portion 20 is also manufactured by the Ni electroforming method, the thickness of the filter portion 20 can be easily changed depending on the position of the ink supply port 19 by changing the thickness of the mask of the resist portion. Thus, it is possible to easily manufacture the filter plate 5 having a different fluid resistance depending on the position from the introduction port 19.

  Here, the planar shape of the filter communication hole 21 is not limited to a circular shape, and may be a polygon that allows efficient alignment of the communication holes 20a (20b). However, since the opening ratio of the communication holes 20a (20b) per unit area is a factor that greatly affects the fluid resistance, it must be taken into account when processing the filter plate.

  In order to make the fluid resistance of the filter unit 20 uniform, the arrangement conditions of the filter communication holes 21 having the same shape are the same, and the fluid resistance of the filter unit 20 is changed only by adjusting the plate thickness of the filter unit 20. In addition, there is no variation between channels in terms of foreign matter collection.

  By the way, in the filter disposed in the common liquid chamber of the ink jet head, an increase in the fluid resistance of the filter portion has a great influence on the ink supply performance, so the pressure loss needs to be as small as possible. Therefore, the filter portion should be made as thin as possible in order to reduce an increase in fluid resistance. However, as a problem that occurs here, the handling property of the filter plate 5 alone due to the thinning, the nozzle plate, and the flow path are reduced. When the filter plate 5 is bonded to the plate or the diaphragm, the filter plate 5 may be bent or the like due to a load at the time of bonding.

  However, in the filter portion of this embodiment, in order to make all the fluid resistance uniform, processing is performed so that the plate thickness at both ends of the filter plate 5 near the ink supply port 19 is thick and the central portion is thin. Therefore, both end portions have higher rigidity than the conventional one. Therefore, it is possible to improve the handleability of the filter plate 5 and the yield reduction due to breakage of the filter plate of the head on which the filter plate is mounted.

In the present embodiment, the plate thickness of the filter unit is set so that the fluid resistance of the filter unit changes in two steps, but the plate of the filter unit is set for each channel depending on the distance from the ink supply port 19. By changing the thickness, it is possible to further reduce the variation in fluid resistance between the channels, and as a result, it is possible to provide a more uniform pressure loss, so that it is possible to provide an inkjet head with good ejection characteristics. It becomes.

  In this way, the filter unit is disposed between the plurality of liquid introduction units that communicate with the plurality of pressurized liquid chambers and the common liquid chamber, and filters the liquid over the entire region in the nozzle arrangement direction of the plurality of individual liquid chambers. The plurality of liquid introduction parts are connected to each other over the entire region in the nozzle arrangement direction, and the length of the filter communication hole is set to the distance from the ink supply part 19. Therefore, the pressure loss applied to the individual liquid chambers can be made uniform, and a good inkjet with little channel variation can be provided.

  Next, an image forming apparatus including the ink jet head of this embodiment will be described with reference to FIGS. 9 and 10.

Here, FIG. 9 is a schematic configuration diagram for explaining the overall configuration of the mechanism section of the apparatus, and FIG. 10 is a plan view of the main section of the mechanism section.
This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in the main scanning direction by main and sub guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 201A and 201B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

  The carriage 233 includes a liquid discharge head according to the present invention for discharging ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K), and a drive signal to the head. A recording head 234 including a liquid discharge head unit in which an electric circuit board to be supplied and a tank for storing ink to be supplied to the head are integrated is arranged in a sub-scanning direction in which a nozzle row including a plurality of nozzles is orthogonal to the main scanning direction. The ink droplet ejection direction is directed downward.

  The recording head 234 is configured by attaching liquid ejection head units 234a and 234b each having two nozzle rows to one base member, and one of the two nozzle rows of the head 234a is black (K). The other two nozzle rows are cyan (C) droplets, the other two nozzle rows of the other head 234b are magenta (M) droplets, and the other two nozzle rows. Ejects yellow (Y) droplets, respectively. In this example, four-color liquid droplets are ejected in a two-head configuration. However, as described above, since four nozzle rows are arranged per head, each of the four colors is ejected by one head. You can also.

  Further, the tanks 4 a and 4 b of the recording head 234 are supplementarily supplied with ink of each color from the ink cartridge 210 of each color by the supply unit 224 via the supply tube 236 of each color.

  On the other hand, as a paper feeding unit for feeding the paper 242 stacked on the paper stacking unit (pressure plate) 241 of the paper feed tray 202, a half-moon roller (feeding) that separates and feeds the paper 242 one by one from the paper stacking unit 241. A separation pad 244 made of a material having a large coefficient of friction is provided opposite to the sheet roller 243 and the sheet feeding roller 243, and the separation pad 244 is urged toward the sheet feeding roller 243 side.

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the recording head 234, a guide member 245 for guiding the sheet 242, a counter roller 246, a conveyance guide member 247, and a tip pressure roller. And a conveying belt 251 which is a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the recording head 234.

  The conveyance belt 251 is an endless belt, and is configured to be wound around the conveyance roller 252 and the tension roller 253 so as to circulate in the belt conveyance direction (sub-scanning direction). In addition, a charging roller 256 that is a charging unit for charging the surface of the conveyance belt 251 is provided. The charging roller 256 is disposed so as to come into contact with the surface layer of the conveyor belt 251 and to rotate following the rotation of the conveyor belt 251. The transport belt 251 rotates in the belt transport direction when the transport roller 252 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 242 recorded by the recording head 234, a separation claw 261 for separating the paper 242 from the transport belt 251, a paper discharge roller 262, and a paper discharge roller 263 are provided. A paper discharge tray 203 is provided below the paper discharge roller 262.

  A double-sided unit 271 is detachably attached to the back surface of the apparatus main body. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.

  Furthermore, a maintenance / recovery mechanism 281 that is a head maintenance / recovery device including a recovery means for maintaining and recovering the state of the nozzles of the recording head 234 is disposed in the non-printing area on one side of the carriage 233 in the scanning direction. Yes. The maintenance / recovery mechanism 281 includes cap members (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the recording head 234, and nozzle surfaces. A wiper blade 283 that is a blade member for wiping the recording medium, and an empty discharge receiver 284 that receives liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid. Yes.

  Further, in the non-printing area on the other side in the scanning direction of the carriage 233, there is an empty space for receiving a liquid droplet when performing an empty discharge for discharging a liquid droplet that does not contribute to the recording in order to discharge the recording liquid thickened during the recording. A discharge receiver 288 is disposed, and the idle discharge receiver 288 is provided with an opening 289 along the nozzle row direction of the recording head 234.

  In this image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide 245, and is conveyed to the conveyor belt 251 and the counter. It is sandwiched between the rollers 246 and conveyed, and further, the leading end is guided by the conveying guide 237 and pressed against the conveying belt 251 by the leading end pressing roller 249, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately applied to the charging roller 256, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 251 alternates, that is, in the sub-scanning direction that is the circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 242 is fed onto the conveyance belt 251 charged alternately with plus and minus, the sheet 242 is attracted to the conveyance belt 251, and the sheet 242 is conveyed in the sub scanning direction by the circumferential movement of the conveyance belt 251.

  Therefore, by driving the recording head 234 according to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper 242 to record one line, and after the paper 242 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 242 has reached the recording area, the recording operation is finished and the paper 242 is discharged onto the paper discharge tray 203.

  Thus, in this image forming apparatus, since the liquid discharge head according to the present invention is provided as a recording head, the reliability is improved.

  An image forming apparatus of a droplet discharge recording system forms an image by discharging ink droplets from an inkjet head onto a sheet transported in the apparatus. Such an image forming apparatus includes a serial type image forming apparatus that forms an image by ejecting droplets while the recording head moves in the main scanning direction, and a state in which the recording head does not move, that is, a fixed recording head. There is a line-type image forming apparatus using a line-type head that forms an image by ejecting liquid droplets in one pass when conveying a sheet in the lower part, and the latter is superior in image forming speed. It is known that Here, the paper is not limited to paper, but means OHP or the like, which means that ink droplets or other liquids can adhere to it, and is also referred to as a recording medium or a recording medium, recording paper, or recording paper. Is done.

  “Ink” is not limited to ink, but is used as a general term for all liquids capable of image formation, such as recording liquid, fixing processing liquid, and liquid. DNA samples, resists, pattern materials, resins and the like are also included.

  Note that image formation not only applies an image having a meaning such as a character or a figure to a medium, but also applies an image having no meaning such as a pattern to the medium (simply landing a droplet on the medium). Examples of terms used synonymously with image formation include recording, printing, printing, printing, and the like.

  An image forming apparatus of a droplet discharge recording system according to the present invention is an apparatus that forms an image by discharging droplets onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, and the like. It is meant in a broad sense.

  In another embodiment of the present invention, the common liquid chamber from the ink supply port to the channel position has a uniform fluid resistance.

  In another embodiment of the present invention, the filter plate is characterized in that the plate thickness is large in the vicinity of the ink supply port, and the plate thickness decreases as the distance from the ink supply port increases.

  In another embodiment of the present invention, the fluid resistance of the filter unit is different for each channel according to the distance from the ink supply port.

  In another embodiment of the present invention, the thickness of the filter plate is different for each channel according to the distance from the ink supply port.

  In another embodiment of the present invention, the filter plate is formed by electroforming.

  In another embodiment of the present invention, a droplet discharge device using an inkjet head may be used.

  In another embodiment of the present invention, an image forming apparatus using an inkjet head may be used.

The above embodiment is a preferable specific example in the ink jet head and the image forming apparatus of the present invention, and may have various technically preferable limitations. However, the technical scope of the present invention is particularly limited to the present invention. Unless stated to limit the invention, it is not limited to these embodiments. Moreover, the component in the said embodiment can be replaced with the existing component etc. suitably, and various variations including the combination with another existing component are possible.
Furthermore, in the above-described embodiment, the example in which the present invention is applied to an image forming apparatus having a printer configuration has been described. However, the present invention is not limited to this. The present invention can be applied to an apparatus, and can also be applied to an image forming apparatus using a liquid other than the narrowly defined ink or a fixing processing liquid. Therefore, the description of the above embodiment does not limit the contents of the invention described in the claims.

DESCRIPTION OF SYMBOLS 1 Flow path board 2 Nozzle plate 3 Vibrating plate member 4 Nozzle 5 Filter plate 6 Pressurizing liquid chamber 7 Fluid resistance part 8 Ink introduction part 10 Partition 10a Recess 12 Piezoelectric element member 12a Piezoelectric element column 17 Frame member 19 Ink supply port 20 Filter Part 20a Communication hole 20b Communication hole 21 Filter communication hole 22 Flow path unit

JP 2007-076093 A JP 2008-213196 A JP 2009-0669904 A

Claims (8)

A nozzle plate having a plurality of nozzles;
A flow path substrate having a pressurized liquid chamber corresponding to the nozzle;
A common liquid chamber communicating with the pressurized liquid chamber;
An inkjet head comprising a filter plate provided in the common liquid chamber,
The ink jet head according to claim 1, wherein the filter plate is disposed over the entire surface of the channel in the nozzle arrangement direction, the thickness varies depending on the distance from the ink supply port, and the fluid resistance decreases as the distance from the ink supply port increases.   The inkjet head according to claim 1, wherein the common liquid chamber from the ink supply port to the channel position has a uniform fluid resistance.   3. The ink jet head according to claim 1, wherein the filter plate has a large plate thickness in the vicinity of the ink supply port, and the plate thickness decreases as the distance from the ink supply port increases.   4. The ink jet head according to claim 1, wherein the fluid resistance of the filter unit is different for each channel according to a distance from the ink supply port. 5.   The inkjet head according to claim 4, wherein the thickness of the filter plate is different for each channel according to a distance from the ink supply port.   The ink jet head according to claim 1, wherein the filter plate is formed by electroforming.   A liquid droplet ejection apparatus using the ink jet head according to claim 1.   An image forming apparatus using the ink jet head according to claim 1.

Images