JP6041010B2 - Liquid ejection head, liquid ejection apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to a liquid ejection head that ejects a recording liquid used for image formation, a liquid ejection apparatus, and an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile machine, a copying machine, a plotter, or a complex machine of these, a liquid ejection head (also referred to as a droplet ejection head) that ejects droplets of a recording liquid (for example, ink) used for image formation is formed. As an image forming apparatus using a recording head, an ink jet recording apparatus or the like is known. This liquid discharge recording type image forming apparatus means that ink droplets from an inkjet head are transported on paper (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected to a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). A serial type image forming apparatus that forms an image by ejecting droplets while the inkjet head moves in the main scanning direction, and a line type head that forms images by ejecting droplets without moving the inkjet head There are line type image forming apparatuses using

  In the present application, the “image forming apparatus” of the liquid discharge recording method is an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or the like. In addition, “image formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply It also means that a droplet is landed on a medium). “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. In addition, the “image” is not limited to a planar one, but includes an image given to a three-dimensionally formed image, and an image formed by three-dimensionally modeling a solid itself.

  By the way, since the liquid ejection head performs recording by ejecting droplets from nozzles (nozzle holes), the shape and accuracy of the nozzles have a great influence on the ejection characteristics of the ink droplets. It is also known that the surface characteristics of the nozzle forming member (nozzle plate) forming the nozzle holes also affect the ink droplet ejection characteristics. For example, if ink adheres to the periphery of the nozzle hole on the surface of the nozzle forming member and a non-uniform ink pool occurs, the ejection direction of the ink droplet is bent, the size of the ink droplet varies, It is known that inconveniences such as unstable flight speed occur.

  For this reason, some liquid ejection heads perform a water repellent treatment (ink repellent treatment) that repels ink on the surface of a nozzle forming member that forms the nozzle. In addition, when a nozzle cover (also referred to as a head cover) that covers the outer peripheral portion (end) of the nozzle forming member is provided, ink accumulation after cleaning the nozzle surface accumulates, and the paper surface is soiled by touching the paper surface. In order to deal with this problem, there is a type in which a water repellent treatment is performed on the opposite surface and side surface of the nozzle cover, and the head base for fixing the head is also subjected to the water repellent treatment. Thus, the structure which covers the outer peripheral part of a nozzle formation member with a nozzle cover is disclosed by patent document 1, 2, for example.

  As described above, in the configurations of Patent Documents 1 and 2, the outer peripheral portion of the liquid discharge surface is covered with the nozzle cover in order to prevent the head member from being peeled off from the head due to stress applied during paper jam or wiping. Protect. An example of this configuration is shown in FIG. FIG. 9A is a top view showing an example in which the outer peripheral portion of a nozzle plate in which a plurality of nozzle holes are formed is covered with a nozzle cover. The nozzle plate and the nozzle cover are fixed by, for example, an adhesive (an example of a resin material). However, such a configuration causes the following problems. This problem will be described with reference to FIGS. 9B to 9D, the figure surrounded by a circle is an enlarged top view showing a portion surrounded by the circle in FIG. 9A, and on the right side of the figure. A certain figure is a sectional side view seen from the transversal direction (wiping direction) of the nozzle plate.

  First, as shown in FIG. 9B, at the time of wiping the nozzle plate, the ink accumulated by the capillary phenomenon between the nozzle cover and the nozzle plate changes to a thickened ink by evaporation of the solvent component in the ink. When wiping is repeated in the state of FIG. 9B, as shown in FIG. 9C, the thickened ink is dragged, diffuses from the nozzle cover to the downstream in the wiping direction, and contaminates the nozzle plate surface. When the wiping is further repeated, a region contaminated with the thickening ink grows from the tip of the nozzle cover to the downstream in the wiping direction, and the region reaches the nozzle hole as shown in FIG. In this way, the thickened ink closes the nozzle holes, leading to non-ejection (a problem in which ink droplets are not ejected) and bending in the ejection direction (a problem in which ink droplets are not ejected in the correct direction).

The present invention has been made in view of the above circumstances, in the liquid discharge head in which the head cover is provided on the outer periphery of the nozzle plate, non-ejection and ejection direction of ink droplets caused by thickened ink blocks the nozzle hole It is an object of the present invention to provide a liquid discharge head, a liquid discharge apparatus, and an image forming apparatus that can prevent bending.

In order to achieve such an object, a liquid discharge head according to the present invention includes a nozzle plate having nozzle holes for discharging droplets and a head cover having an opening through which the nozzle holes are exposed, and a resin is provided between the head cover and the nozzle plate. The resin material that is buried in the material and exposed from the opening of the head cover is against the surface of the nozzle plate so that the exposed surface connects between the surface of the nozzle plate and the droplet discharge side surface of the head cover. Inclined, the thickness of the resin material on the nozzle hole side becomes thinner toward the nozzle hole, and there is no resin material on the droplet discharge side surface of the head cover .

  The liquid discharge apparatus of the present invention includes the liquid discharge head of the present invention.

  An image forming apparatus according to the present invention includes the liquid discharge head according to the present invention.

According to the present invention can be in the liquid discharge head in which the head cover is provided on the outer periphery of the nozzle plate, thickened ink to prevent bending non-ejection and ejection direction of ink droplets caused by blocking the nozzle hole.

It is a figure which shows the upper surface and side cross section of the nozzle plate and nozzle cover of a liquid discharge head which concern on one Embodiment of this invention. It is a figure which shows the side cross section of the nozzle plate and nozzle cover of the liquid discharge head which concerns on one Embodiment of this invention. It is a figure which shows the side cross section of the nozzle cover of the liquid discharge head which concerns on one Embodiment of this invention. FIG. 5 is a cross-sectional explanatory view along the longitudinal direction of the liquid chamber of the liquid discharge head according to the embodiment of the present invention. 1 is a schematic configuration diagram illustrating an overall configuration of a mechanism unit of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a plan view illustrating a main part of a mechanism unit of the image forming apparatus according to the embodiment of the present invention. 1 is a schematic configuration diagram of an entire mechanism unit of an image forming apparatus according to an embodiment of the present invention. 1 is a diagram illustrating a configuration of a recording head of an image forming apparatus according to an embodiment of the present invention. It is a figure explaining the subject which this invention solves, and is a figure showing the upper surface and side section of a nozzle plate and a nozzle cover.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  An example of the overall configuration of the liquid ejection head of this embodiment will be described with reference to FIG. FIG. 4 is a cross-sectional explanatory view along the longitudinal direction of the liquid chamber of the liquid discharge head of this embodiment.

  As shown in FIG. 4, the liquid discharge head of the present embodiment includes a flow path plate 1 that is a flow path forming member made of, for example, a silicone member, and a nozzle forming member (for example, a metal member) joined to the upper surface of the flow path plate 1. And a diaphragm 3 made of a metal member joined to the lower surface of the flow path plate 1. The nozzle plate 2 is provided with a plurality of nozzles (nozzle holes) 4 for ejecting liquid droplets (liquid droplets of recording liquid used for image formation, such as ink droplets). The liquid droplets are discharged from the nozzle 4 through the pressurized liquid chamber 6 from the common liquid chamber 10 formed in the frame member 17. It is to be noted that a vibration plate 3 is formed on the vibration plate 3 corresponding to each pressure liquid chamber 6 on the outer side of the vibration plate 3 forming the wall surface of the pressure liquid chamber 6 (on the side opposite to the pressure liquid chamber 6). The upper end surface of the multilayer piezoelectric element 12 as a driving element is joined via the connecting portion. Further, the lower end surface of the multilayer piezoelectric element 12 is joined to the base member 13.

  As shown in FIG. 4, the liquid discharge head of this embodiment is equipped with a nozzle cover 51 that protects the outer peripheral portion of the nozzle plate 2 and the side surface of the liquid discharge head. The surface portion (outer surface) 51a of the nozzle cover 51 that faces at least a recording material surface (for example, a recording member such as paper on which a droplet is discharged to form an image) is subjected to water repellent treatment. A second water repellent layer 42 is formed. The second water repellent layer 42 is different from the first water repellent layer 41 on the surface (liquid ejection surface) of the nozzle plate 2 on which the nozzles 4 are formed. In this way, by forming the water repellent layer 42 on the outer surface 51a of the nozzle cover 51, not only the liquid ejection surface of the nozzle plate 2 but also the outer surface of the nozzle cover 51 can have a water repellency effect. Both the nozzle plate 2 and the nozzle cover 51 can be cleaned, and the ink can be removed to the outside of the nozzle cover 51. An example of the water repellent treatment in the nozzle cover 51 will be described later with reference to FIG.

  When the droplet discharge head according to the present embodiment configured as described above is driven by, for example, a pushing method, the plurality of piezoelectric elements 12 are driven at 20 to 50 V according to an image recorded from a control unit (not shown). By selectively applying the pulse voltage, the piezoelectric element 12 to which the pulse voltage is applied is displaced to deform the vibration plate 3 in the direction of the nozzle plate 2, and the liquid chamber is changed by changing the volume of the pressurized liquid chamber 6. By pressurizing the liquid in 6, droplets are ejected from the nozzle 4 of the nozzle plate 2. As the liquid droplets are discharged, the pressure in the liquid chamber 6 decreases, and a slight negative pressure is generated in the liquid chamber 6 due to the inertia of the liquid flow at this time. Under this state, by turning off the application of voltage to the piezoelectric element 12, the diaphragm 3 returns to the original position and the liquid chamber 6 becomes the original shape, and thus a negative pressure is further generated. At this time, the recording liquid is filled from the common liquid chamber 10 into the liquid chamber 6, and droplets are ejected from the nozzles 4 in response to the next drive pulse application.

  Next, a characteristic configuration of the liquid discharge head according to the present embodiment will be described with reference to FIG.

  FIG. 1A is a top view of the nozzle plate 2. As shown in FIG. 1A, the nozzle plate 2 is covered with a nozzle cover 51 at the outer periphery (end). A plurality of nozzles 4 are provided on the surface of the nozzle plate 2 to form a liquid discharge surface. The wiping direction on the liquid ejection surface is the same as the arrow shown in FIG.

  FIG. 1B is an enlarged view (a side cross-sectional view of the nozzle plate 2 as viewed from the short side direction) of the portion surrounded by a circle in FIG. FIG. 1B shows a state before the nozzle cover 51 is attached. In FIG. 1B, a portion covered with the nozzle cover 51 on the liquid ejection surface of the nozzle plate 2 is indicated by a broken line, and a region to be hydrophilized (hydrophilic region) is indicated by an alternate long and short dash line.

  FIG. 1C shows a state in which a nozzle cover 51 is attached to the nozzle plate 2 of FIG. As shown in FIG. 1C, the nozzle cover 51 has an opening (an opening formed by the nozzle cover 51 and the nozzle plate 2), and the liquid discharge surface of the nozzle plate 2 than the outer periphery of the nozzle cover 51. Is formed with an inclination in the direction of the opening of the nozzle cover 51. The tip of the opening of the nozzle cover 51 has an inclined surface that is closer to the liquid ejection surface than the surface perpendicular to the thickness direction of the nozzle cover 51. Further, as shown in FIG. 1C, a resin material is filled so as to fill a gap (step) between the inclined surface and the nozzle plate 2. The colored portion in the figure indicates the filling of the resin material. This resin material covers the inclined surface. Further, this resin material is an adhesive, and examples thereof include a silicone-based adhesive. By embedding this adhesive, the nozzle cover 51 is fixed to the nozzle plate 2 and the opening of the nozzle cover 51 is closed. As shown in FIG. 2, the step y when the tip of the nozzle cover is cut off at a right angle (in the direction of arrow a) and the tip of the nozzle cover are cut off in a reverse taper with respect to the wiping direction as in this embodiment. X is shorter when compared with the step x in the case of the difference. Therefore, it becomes easy to fill the gap with the resin material, and the accumulation of the thickened ink due to insufficient filling is less likely to occur. According to the above configuration, the liquid droplet does not enter the gap between the nozzle cover 51 and the nozzle plate 2 and the liquid droplet does not remain. Therefore, it is possible to prevent droplets from collecting in the opening of the nozzle cover and becoming fixed ink. As a result, it is possible to prevent the thickening ink as described in FIG. 9 from diffusing in the nozzle 4 direction.

  In addition, on the liquid ejection surface of the nozzle plate 2 shown in FIG. 1C, the region exposed from the opening of the nozzle cover 51 (the region that is not covered by the nozzle cover 51 and is in the upward direction of the extension of the hydrophilic region) is As shown by the two-dot chain line, it is a water repellent region, and a water repellent layer (first water repellent layer 41 shown in FIG. 4) is formed. Further, in the liquid discharge surface of the nozzle plate 2 shown in FIG. 1C, the region facing the inclined surface of the nozzle cover 51 is a hydrophilic region as shown by a one-dot chain line, and a hydrophilic layer is formed. . With such a configuration, the adhesion (bondability) of the nozzle cover 51 to the nozzle plate 2 is improved.

  In addition, you may comprise so that it may have a hydrophilic layer in the surface (for example, inner surface shown in FIG.1 (c)) and inclined surface which oppose the nozzle plate 2 of the nozzle cover 51. FIG. Thereby, the adhesiveness (joinability) with respect to the nozzle plate 2 of the nozzle cover 51 improves.

  Further, as shown in FIG. 2, the hydrophilic layer formed on the liquid ejection surface of the nozzle plate 2 (the hydrophilic layer formed in the hydrophilic region indicated by the alternate long and short dash line) extends from the tip of the opening of the nozzle cover 51 to the nozzle hole. 4, the nozzle cover 51 is formed so as to protrude in a direction equivalent to the thickness of the nozzle cover 51 (b> a), and the nozzle cover 51 (the outer surface thereof) and the liquid discharge surface of the nozzle plate 2 are continuously made of a resin material spreading in the hydrophilic region. It is formed to be a surface.

  For example, the water repellent treatment of the nozzle cover 51 includes the following two methods. In the first example, water repellent treatment is performed as shown in FIGS. For example, assuming that a quick-drying material is used, water repellent treatment is performed as shown in FIGS. The entire nozzle cover 51 whose tip is not processed is simply dipped into a water repellent liquid (for example, a quick-drying one). When the water repellent liquid is dried, a water repellent film (portion indicated by a thick line) is formed on the entire surface of the nozzle cover as shown in FIG. Thereafter, as shown in FIG. 3B, the tip of the nozzle cover 51 is processed into an inversely tapered shape to form an inclined surface. Further, as shown in FIG. 3B, the water repellent film on the inclined surface and part of the inner surface (part of the surface facing the nozzle plate 2) is removed. As described above, a hydrophilic layer may be formed on the water repellent film removal portion. In the second example, water repellent treatment is performed as shown in FIGS. A water repellent liquid (for example, a quick-drying one) is applied to the outer surface of the nozzle cover 51 whose tip is not processed. When the water repellent material liquid is dried, a water repellent film (portion indicated by a thick line) is formed on the outer surface of the nozzle cover 51 as shown in FIG. Thereafter, as shown in FIG. 3D, the tip of the nozzle cover 51 is processed into an inversely tapered shape to form an inclined surface. As described above, a hydrophilic layer may be formed on the inclined surface and a part of the inner surface (a part of the surface facing the nozzle plate 2).

  When the nozzle cover 51 processed as shown in FIG. 3B or FIG. 3D is fitted into the liquid discharge head, the surface of the nozzle plate 2 is bonded to the outer periphery of the nozzle plate 2 via an adhesive applied in advance. Fixed to. Alternatively, the nozzle cover 51 processed as described above may be fixed by pouring an adhesive into the gap between the nozzle cover 51 and the liquid ejection surface of the nozzle plate 2 after being fitted into the liquid ejection head. .

  The one where the viscosity of the said adhesive agent is low is preferable. The reason is that the nozzle cover and the liquid discharge surface are filled with a capillary force so as to smoothen the step. Further, it is preferable to use an adhesive having relatively water repellency for the adhesive itself. The reason is that the amount of ink adhering to the adhesive can be suppressed and the generation of thickened ink can be suppressed.

  As described above, according to the liquid discharge head of this embodiment, even if the nozzle cover has the same plate thickness, the nozzle cover and the liquid discharge surface (nozzle surface) are provided by providing a reverse taper at the tip. ) Can be made smaller, and ink can be made difficult to accumulate in the stepped portion. Therefore, it is possible to greatly suppress the nozzle surface contamination and ejection abnormality caused by the ink accumulation in the stepped portion. That is, in the configuration in which the nozzle cover is provided on the outer peripheral portion of the nozzle plate, it is possible to prevent non-ejection of ink droplets and bending in the ejection direction caused by the thickened ink blocking the nozzle holes. Further, according to the liquid discharge head of the present embodiment, in addition to reducing the stepped portion, the step is further inclined to make it difficult for ink to collect at the boundary between the nozzle cover and the liquid discharge surface. Can be further. Further, according to the liquid discharge head of this embodiment, the liquid discharge surface and the nozzle cover are fixed by bonding the hydrophilic region of the inner wall (inner surface) of the nozzle cover and the hydrophilic region of the liquid discharge surface of the nozzle plate. However, since the taper cross section (inclined surface) is also bonded and fixed, it is possible to prevent ink from entering the interface between the cover taper portion and the adhesive, thereby further suppressing the generation of thickened ink. Further, according to the liquid discharge head of this embodiment, by imparting water repellency to the adhesive itself, it is possible to prevent ink from adhering to the adhesive and to further suppress the generation of thickened ink.

  Next, an example of an image forming apparatus including the liquid ejection head according to the present embodiment will be described with reference to FIGS. FIG. 5 is a schematic configuration diagram for explaining the overall configuration of the mechanism portion of the apparatus, and FIG. 6 is a plan view for explaining a main portion of the mechanism portion.

  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 slave guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 221A and 221B. 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 is driven by the liquid ejection head of the present embodiment described above for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). A recording head 234 composed of a liquid discharge head unit in which an electric circuit board for supplying a signal and a tank for storing ink to be supplied to the head are integrated into a nozzle array composed of a plurality of nozzles in a sub-scanning direction orthogonal to the main scanning direction. They are arranged and mounted with the ink droplet ejection direction facing downward. Since the carriage 233 includes the liquid discharge head of this embodiment, it can be called a “liquid discharge apparatus”.

  The recording head 234 is configured by attaching liquid discharge head units 234a and 234b each having two nozzle rows to one base member, and one nozzle row of one head 234a receives black (K) droplets. The other nozzle row ejects cyan (C) droplets, the other nozzle row of the other head 234b ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets. To do. Here, a configuration in which droplets of four colors are ejected in a two-head configuration is used, but it is also possible to arrange four nozzle rows per head and eject each of the four colors with one head.

  Further, the ink of each color is replenished and supplied from the ink cartridge 210 of each color to the tank 235 of the recording head 234 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 conveyor belt 251 is an endless belt, and is configured to wrap around the conveyor 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 transport 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.

  Further, a maintenance / recovery mechanism 281 that is a head maintenance / recovery device according to the present invention includes a recovery means for maintaining and recovering the nozzle state of the recording head 234 in the non-printing area on one side of the carriage 233 in the scanning direction. Is arranged. The maintenance / recovery mechanism 281 includes a cap member (hereinafter referred to as “cap”) 282a and 282b (hereinafter referred to as “cap 282” when not distinguished) and a nozzle surface for capping each nozzle surface of the recording head 234. A wiper blade 283 that is a blade member for discharging, a blank discharge receiver 284 that receives a droplet when performing a blank discharge that discharges a droplet that does not contribute to recording in order to discharge the thickened recording liquid, and the like. .

  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 and the like.

  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.

  As described above, the image forming apparatus includes the above-described liquid discharge head according to the present embodiment as a recording head, so that reliability is improved.

  Next, another example of the image forming apparatus including the liquid discharge head according to the present embodiment will be described with reference to FIG. FIG. 7 is a schematic configuration diagram of the entire mechanism section of the apparatus.

  This image forming apparatus is a line type image forming apparatus, has an image forming unit 402 and the like inside the apparatus main body 401, and can supply a large number of recording media (sheets) 403 on the lower side of the apparatus main body 401. A paper tray 404 is provided, a sheet 403 fed from the sheet feeding tray 404 is taken in, a required image is recorded by the image forming unit 402 while the sheet 403 is conveyed by the conveying mechanism 405, and then the side of the apparatus main body 401. The paper 403 is discharged to a paper discharge tray 406 attached to the printer.

  Also, a duplex unit 407 that can be attached to and detached from the apparatus main body 401 is provided, and when performing duplex printing, the sheet 403 is conveyed into the duplex unit 407 while being transported in the reverse direction by the transport mechanism 405 after one-side (front) printing is completed. Then, the other side (back side) is sent back to the transport mechanism 405 as the printable side, and the paper 403 is discharged to the paper discharge tray 406 after the other side (back side) printing is completed.

  Here, the image forming unit 402, for example, discharges liquid droplets of each color of yellow (Y), magenta (M), cyan (C), and black (K) according to four line type liquids according to the present embodiment. The recording heads 411y, 411m, 411c, and 411k (referred to as “recording heads 411” when colors are not distinguished) are configured by integrating a discharge head and a sub-tank that supplies ink to the liquid discharge head. The head holder 413 is mounted with the nozzle surface on which the nozzle for discharging droplets is formed facing downward.

  As shown in FIG. 8, one recording head 411 includes a plurality of (six in this example) liquid tanks 501 </ b> A to 501 </ b> F according to the present embodiment integrated with a sub tank in a predetermined positional relationship with the base member 502. Although it is configured by arranging, it can also be configured by one full line type liquid discharge head.

  In addition, a maintenance / recovery mechanism 412y, 412m, 412c, 412k (referred to as “maintenance / recovery mechanism 412” when colors are not distinguished) corresponding to each recording head 411 is provided to maintain and recover the performance of the head. During the head performance maintenance operation such as wiping processing, the recording head 411 and the maintenance / recovery mechanism 412 are relatively moved so that the capping member constituting the maintenance / recovery mechanism 412 faces the nozzle surface of the recording head 411.

  The paper 403 in the paper feed tray 404 is separated one by one by a paper feed roller (half-moon roller) 421 and a separation pad (not shown) and fed into the apparatus main body 401, and is registered along the guide surface 423 a of the transport guide member 423. It is sent between 425 and the conveyor belt 433, and is sent to the conveyor belt 433 of the conveyor mechanism 405 via the guide member 426 at a predetermined timing.

  The conveyance guide member 443 is also formed with a guide surface 423 b for guiding the paper 403 sent out from the duplex unit 407. Further, a guide member 427 for guiding the sheet 403 returned from the transport mechanism 405 to the duplex unit 407 during duplex printing is also provided.

  The conveyance mechanism 405 includes an endless conveyance belt 433 that is stretched between a conveyance roller 431 that is a driving roller and a driven roller 432, a charging roller 434 that charges the conveyance belt 433, and an image forming unit 402. A platen member 435 that maintains the flatness of the conveyance belt 433 at the opposite portion, a pressing roller 436 that presses the paper 403 fed from the conveyance belt 433 against the conveyance roller 431 side, and other recording liquid that is attached to the conveyance belt 433, although not shown. It has a cleaning roller made of a porous material or the like, which is a cleaning means for removing (ink). As the transport mechanism, for example, a mechanism that sucks the recording medium onto the transport belt by air suction can be used.

  On the downstream side of the transport mechanism 405, a paper discharge roller 438 and a spur 439 for sending the paper 403 on which an image is recorded to the paper discharge tray 406 are provided.

  In the image forming apparatus configured as described above, the conveyance belt 433 moves in the direction indicated by the arrow and is charged by contact with the charging roller 434 to which a high applied voltage is applied. When 403 is fed, the sheet 403 is electrostatically attracted to the conveyance belt 433. In this way, the sheet 403 that is strongly adsorbed to the transport belt 433 is calibrated for warpage and unevenness, and forms a highly flat surface.

  Then, the paper 403 is moved around the conveyor belt 433 and droplets are ejected from the recording head 411, whereby a required image is formed on the paper 403, and the paper 403 on which the image has been recorded is the paper discharge roller 438. As a result, the paper is discharged to the paper discharge tray 406.

  As described above, since the image forming apparatus includes the liquid discharge head according to the present embodiment, the discharge efficiency and the image quality can be improved, and the reliability of image formation is improved.

  In the above embodiment, an image forming apparatus having a printer configuration has been described as an example. However, the present invention is not limited to this, and as described above, the image forming apparatus can be applied to an image forming apparatus such as a printer / fax / copier multifunction machine. In addition, as described above, the present invention can also be applied to an image forming apparatus using a liquid other than the narrowly defined ink or a fixing processing liquid.

  The embodiment of the present invention has been described above, but the present invention is not limited to the description of the embodiment, and various modifications can be made without departing from the scope of the invention.

1 Channel plate 2 Nozzle plate (nozzle plate)
DESCRIPTION OF SYMBOLS 3 Diaphragm 4 Nozzle hole 6 Pressurized liquid chamber 10 Common liquid chamber 12 Stacked piezoelectric element 13 Base member 17 Frame member 41 First water repellent layer 42 Second water repellent device 51 Nozzle cover 51 Nozzle cover outer surface

JP 2006-334903 A JP 2009-220421 A

Claims (7)

A nozzle plate having a nozzle hole for discharging droplets, and a head cover having an opening through which the nozzle hole is exposed,
The space between the head cover and the nozzle plate is filled with a resin material,
The resin material exposed from the opening of the head cover is inclined with respect to the surface of the nozzle plate so that the exposed surface connects between the surface of the nozzle plate and the surface of the head cover on the droplet discharge side. And on the nozzle hole side of the resin material, the thickness is reduced toward the nozzle hole ,
The liquid discharge head, wherein the resin material is not present on the surface of the head cover on the droplet discharge side .   The liquid discharge head according to claim 1, wherein a side surface of the opening of the head cover is covered with the resin material. The water repellent layer is formed on the droplet discharge side surface of the head cover, and a hydrophilic layer is formed on the side surface of the opening of the head cover covered with the resin material. Liquid discharge head. The liquid discharge head according to claim 3, wherein a hydrophilic layer is formed on a portion of the nozzle plate covered with the resin material.   The liquid discharge head according to claim 1, wherein the resin material is an adhesive.   A liquid discharge apparatus comprising the liquid discharge head according to claim 1.   An image forming apparatus comprising the liquid discharge head according to claim 1.

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