JP2010214743A - Liquid discharge head, head cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high density and highly reliable liquid discharge head capable of stably discharging despite the environmental change, a head cartridge, and an image forming apparatus. <P>SOLUTION: The liquid discharge head has a liquid chamber unit constituted by connecting a nozzle substrate having nozzles for discharging liquid, a liquid chamber for storing the liquid in communication with the respective nozzles including flowing channels, and a diaphragm formed at least a part of the wall of the liquid chamber, a drive means for generating pressure for pressurizing the liquid in the liquid chamber, a frame member supporting the liquid chamber unit and having a common liquid chamber, and a heating means for heating the liquid discharged by the frame member. Further, the frame member in the liquid discharge head is formed of a plurality of kinds of members having different thermal conductivities, a site having the heating means of the frame member is formed of a high thermal conductive member, and a site formed of a low thermal conductive member is arranged in the drive means side of the high thermal conductive member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid discharge head, an ink cartridge, and an image forming apparatus, and more particularly, to a liquid discharge head that discharges liquid from a nozzle by displacing a diaphragm by a driving unit such as a piezoelectric element.

  An ink jet recording apparatus used as an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, or a plotter has a nozzle that discharges droplets, a pressure chamber, a pressurized liquid chamber, a liquid chamber, an ink chamber, and a flow path that communicate with the nozzle. And the like, and an actuator means for generating energy to pressurize the liquid in the discharge chamber, and the actuator means is driven to pressurize the liquid in the discharge chamber and discharge droplets from the nozzles. Ink-on-demand systems, which eject droplets only when recording is necessary, are the mainstream.

  By the way, due to the demand for higher recording speed and higher recording density, a multi-nozzle head having a plurality of nozzles is used, and the required droplet size tends to be further reduced. Therefore, the liquid chamber tends to be made smaller. In order to make the nozzle pitch fine, it is necessary not only to shorten the width direction but also to shorten the length direction of the liquid chamber. This is because small droplets are ejected by increasing the pressure resonance frequency of the liquid chamber.

  On the other hand, as described in Patent Document 1, a temperature detection element for detecting temperature is provided on a support provided with an electrothermal converter that generates thermal energy for discharging liquid, thereby controlling the viscosity of the liquid. For this reason, recording heads that apply heat and manage the heat have been proposed. Further, Patent Document 2 discloses an inkjet in which the base material of the partition is formed of an electric / heat exchange material that generates heat when energized, and the ink liquid in the individual liquid chamber is heated by energizing the partition and generating heat from the partition. A head has been proposed.

  However, in such a high-density and small-sized head as described above, when such viscosity control is performed, the space for arranging the heating source becomes a problem. Specifically, since the drive means has an electric control part and dislikes heat, it is preferable to keep it away from the heating source as much as possible, but by increasing the density of the liquid chamber, the distance between the frame and the drive means also approaches, This causes problems in the electric control unit such as the driving means.

  SUMMARY An advantage of some aspects of the invention is to provide a high-density, high-reliability liquid discharge head, a head cartridge, and an image forming apparatus that can stably discharge regardless of environmental changes. And

  In order to solve the above problems, a liquid discharge head according to the present invention includes a nozzle substrate having a nozzle for discharging a liquid, a liquid chamber for storing a liquid communicated with each nozzle including a flow path, and at least one of the liquid chambers. A liquid chamber unit joined to a diaphragm forming a wall surface of the unit, a driving means for generating pressure for pressurizing the liquid in the liquid chamber, a frame member that supports the liquid chamber unit and has a common liquid chamber, And heating means for heating the liquid discharged to the frame member. The frame member in the liquid discharge head according to the present invention is formed of a plurality of types of members having different thermal conductivities, and the portion provided with the heating means of the frame member is formed of the high heat conductive member, and on the drive means side of the high heat conductive member. It is characterized in that a portion formed of a low heat conductive member is provided. Moreover, the outer peripheral part of a high heat conductive member is formed with a low heat conductive member. Therefore, by using a low heat conduction member on the outer periphery of the frame near the drive means and using a high heat conduction member that can be heated by the heating means on the inside, the viscosity of the liquid can be controlled and heat is not easily dissipated around the head. Thus, the failure of the electric circuit portion of the driving means caused by the heat from the heating means is eliminated, and a high quality and highly reliable liquid discharge head can be provided.

  Further, the flow path on the frame member side that supplies the liquid from the common liquid chamber to the liquid chamber of the liquid chamber unit serves as a fluid resistance portion, so that the pressure wave generated on the individual liquid chamber side can propagate to the common liquid chamber. In addition, high-quality discharge is possible, and it is not necessary to provide fluid resistance on the liquid chamber substrate, and it is not necessary to reduce the size of the head or to provide a complicated liquid chamber structure, so that the rigidity of the liquid chamber itself is increased.

  Furthermore, by providing a filter in the flow path on the frame member side that supplies liquid from the common liquid chamber to the liquid chamber of the liquid chamber unit, foreign matters are not brought into the flow path, and problems such as nozzle clogging are eliminated. High quality and long life liquid discharge head can be provided.

  Further, by providing a damper on the frame member that supplies the liquid from the common liquid chamber to the liquid chamber of the liquid chamber unit, it is possible to absorb the pressure wave generated in the common liquid chamber and the inertia of the liquid due to the liquid supply.

  Further, the frame member is formed of a member having higher rigidity than the flow path unit. The liquid chamber substrate in which the liquid chamber is formed by machining is deformed and it is difficult to perform uniform bonding, but the flow path can be obtained by making the frame member bonded to the liquid chamber unit a highly rigid member. The deformation of the unit can be corrected, and uniform bonding is possible. In addition, since the liquid chamber unit is supported by a high-rigidity member, the loss of energy given to the liquid chamber by the drive means can be prevented, so the discharge efficiency is high, and the high-density liquid discharge head that can realize high quality and high reliability. Can provide.

  In addition, since the machining for forming the liquid chamber substrate is press processing, a liquid chamber with high density and high accuracy can be formed at low cost.

  Furthermore, a head cartridge as another invention is characterized in that the above-described liquid discharge head is mounted. Therefore, it is possible to provide an ink cartridge that can satisfy high density, high quality, high image quality, and low cost.

  An image forming apparatus as another invention is characterized in that the above-described liquid discharge head is mounted. Therefore, an image forming apparatus that can satisfy high density, high quality, high image quality, and low cost can be provided.

  According to the liquid discharge head of the present invention, the viscosity of the liquid can be controlled by using a low heat conductive member on the outer peripheral portion of the frame close to the driving means and using a high heat conductive member that can be heated by the heating means on the inner side. It is difficult for heat to be dissipated around the motor, and the failure of the electric circuit portion of the driving means caused by the heat of the heating means is eliminated, and a high-quality and highly reliable liquid discharge head can be provided.

FIG. 2 is a cross-sectional view illustrating a configuration of a liquid discharge head according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a liquid discharge head according to an embodiment of the present invention. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. It is sectional drawing which shows the high-density structure of a liquid chamber. It is sectional drawing which shows the electroforming process of the 2-layer diaphragm of Ni electroforming. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. It is sectional drawing which shows another structure of the liquid discharge head which concerns on one embodiment of this invention. 1 is a side view showing an overall configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a plan view showing a main configuration of an image forming apparatus according to an embodiment of the present invention.

10, 70; liquid chamber substrate, 11; liquid chamber, 12; liquid resistance portion,
13; Common liquid chamber, 20; Nozzle plate, 21; Nozzle, 30;
31; Diaphragm part, 32; Convex part, 33; Thick part,
34; liquid supply port, 40; laminated piezoelectric element, 41; electrode laminated portion,
42; drive unit, 43; support member, 50; base substrate, 60; frame,
80; heater; 81; high thermal conductivity member; 82; low thermal conductivity member;
83; Electric control unit, 84; Fluid resistance unit, 85; Filter,
86; damper, 87; low thermal conductive adhesive, 100; image forming apparatus.

  1 to 3 are cross-sectional views showing the configuration of a liquid discharge head according to an embodiment of the present invention. FIG. 1 is a cross-sectional view along the longitudinal direction of the liquid chamber, that is, the direction intersecting the nozzle arrangement direction. 2 and 3 are cross-sectional views along the minor axis direction of the liquid chamber, that is, along the nozzle arrangement direction. Note that the liquid to be ejected may not be ink. In addition, although the description will be made centering on the flat surface here, the surface of the member may have a plurality of irregularities.

  The liquid discharge head shown in FIGS. 1 and 2 includes a liquid chamber substrate 10 that forms the liquid chamber 11 and the fluid resistance portion 12, and a nozzle plate that forms nozzles 21 that discharge droplets bonded to the upper surface of the liquid chamber substrate 10. 20, a diaphragm 30 bonded to the lower surface of the liquid chamber substrate 10 and having a diaphragm portion 31, and a laminated piezoelectric element 40 which is bonded to the diaphragm 30 and is a pressure changing means for changing the pressure in the liquid chamber 11. And a base substrate 50 for fixing the laminated piezoelectric element 40. Further, according to the liquid discharge head of the present embodiment, the frame member is formed of two or more members having different thermal conductivities, the heater 80 is provided to control the viscosity of the liquid, and the common liquid chamber is further provided. The member forming the common liquid chamber uses the high thermal conductivity member 81 having high thermal conductivity in order to heat and retain the liquid in which 13 is accumulated. Further, the outer peripheral portion of the frame member close to the driving means is formed of a low thermal conductivity member 82. Each member is bonded with an adhesive layer, but the adhesive layer is not shown in FIGS. 1 and 2 because it is thinner than other members. Moreover, the structure which provides the convex part 32 and the thick part 33 as shown in FIG.

  The laminated piezoelectric element 40 in the liquid discharge head includes a piezoelectric material layer, an electrode layer, and a piezoelectric material layer, as shown in FIG. 1B and an enlarged view of a broken line portion in FIG. Are laminated, and the liquid in the liquid chamber 11 is pressurized using displacement in the d33 direction as the piezoelectric direction of the laminated piezoelectric element 40. Also, as shown in FIGS. 2 and 3, the laminated piezoelectric element 40 is divided on the comb teeth by half-cut dicing, and each of them is used as a driving part 42 and a supporting member 43 that is a non-driving part of the piezoelectric element. use. This structure is called a bi-pitch structure. Since the flow path unit is supported by the support member 43, the liquid chamber substrate 10 is prevented from being lifted by a rise in the pressure of the liquid chamber 11, and is very effective in suppressing so-called mutual interference.

  As can be seen from FIG. 4 showing another embodiment of the present invention showing a structure in which the liquid chambers 11 are densified, the driving portion 42 of the laminated piezoelectric element 40 is supported at the same interval as the nozzle pitch. A structure in which the member 43 is not formed (normal pitch structure) may be used. The material of the liquid chamber substrate 10 may be Si, Ni, 42 alloy, SUS304, or another SUS material. A liquid-resistant thin film made of an organic resin film such as a titanium nitride film or polyimide may be formed on the surface of the liquid chamber substrate 10 in contact with the liquid. By forming such a liquid-resistant thin film, the material of the liquid chamber substrate 10 is less likely to elute from the liquid, and the wettability is improved, so that bubbles are less likely to stay and stable droplet ejection is possible. Become. Here, “layer” and “film” are used to mean all substantially flat structures.

  1 and 2, the liquid chamber substrate 10 has a thickness of 40 μm to 600 μm (a liquid chamber may be formed by stacking the liquid chamber substrates 10). The length in the longitudinal direction was 400 μm to 1600 μm, and the width of the liquid chamber 11 was 120 to 139 μm. The width of the flow path partition is about 15 to 50 μm (because the liquid chamber pitch is 150 dpi) at the joint surface with the diaphragm 30.

  Further, the liquid chamber substrate 10 of the liquid discharge head shown in FIG. 4 has a thickness of 100 μm to 600 μm (a liquid chamber may be formed by stacking the liquid chamber substrates 10), and the length of the liquid chamber 11 in the longitudinal direction. The thickness may be 400 μm to 1600 μm, and the width of the liquid chamber 11 may be 50 to 70 μm (because the liquid chamber pitch is 300 dpi). The nozzle plate 20 is formed of a metal material, for example, an Ni plating film formed by an electroforming method, and has a number of nozzles 21 that are fine discharge ports for causing droplets to fly. The internal shape (inner shape) of the nozzle 21 is formed in a horn shape (may be a substantially cylindrical shape or a substantially frustum shape). Further, the diameter of the nozzle 21 is about 15 to 35 μm on the droplet outlet side. The diameter of the nozzle 21 here was 18 to 26 μm. Further, the nozzle pitch of each row is 150 dpi / 300 dpi. A resin material may be used as the material of the nozzle plate 20.

  Further, a water repellent treatment layer (not shown) subjected to a water repellent surface treatment is provided on the liquid ejection surface (nozzle surface side) of the nozzle plate 20. Liquid physical properties such as PTFE-Ni eutectoid plating, electrodeposition coating of fluororesin, vapor-deposited fluororesin (for example, fluoride pitch), baking after solvent coating of silicon resin / fluorine resin, etc. A water repellent treatment film selected according to the above is provided to stabilize the liquid droplet shape and flight characteristics so that high-quality image quality can be obtained.

  As shown in FIG. 1, the liquid supply port 34 for supplying liquid from the outside and the frame 60 formed by the engraving that becomes the common liquid chamber 13 are formed of two or more kinds of members having different thermal conductivities. The heater 80 is provided to control the viscosity of the liquid, and the member forming the common liquid chamber in order to heat and keep the liquid stored in the common liquid chamber 13 is replaced with the high thermal conductivity member 81 having high thermal conductivity. I use it. The frame 60 on the side close to the driving means is formed of a low thermal conductivity member 82.

  In the liquid ejection head having such a configuration, a displacement in the stacking direction occurs in the multilayer piezoelectric element 40 by applying a driving waveform (pulse voltage of 10 to 50 V) to the multilayer piezoelectric element 40 according to the recording signal. The liquid chamber 11 is pressurized through the vibration plate 30 to increase the pressure, and droplets are ejected from the nozzle 21. Thereafter, the liquid pressure in the liquid chamber 11 is reduced with the end of droplet discharge, and a negative pressure is generated in the liquid chamber 11 due to the inertia of the liquid flow and the discharge process of the driving pulse, and the liquid filling process is started. . At this time, the liquid supplied from the liquid tank flows into the common liquid chamber 13, passes from the common liquid chamber 13 through the liquid inflow port 34, passes through the fluid resistance portion 12, and is filled into the liquid chamber 11. The fluid resistance portion 12 is effective in damping the residual pressure vibration after ejection, but becomes resistant to refilling (refill) due to surface tension. By appropriately selecting the fluid resistance portion, it is possible to balance the attenuation of the residual pressure and the refill time, and to shorten the time (drive period) until shifting to the next droplet discharge operation.

  Here, as the shape of the convex portion 32 and the thick portion 33 in the configuration of FIG. 3, there is a configuration in which the periphery of the convex portion 32 is surrounded by the thin portion 31 and the periphery is surrounded by the thick portion 33. As a forming method, there is a method of stacking two Ni plating films by an electroforming method. Moreover, you may form a rib (projection) by this electroforming method.

  Next, the electroforming process of the Ni electroformed two-layer diaphragm will be described with reference to FIG. A first layer 72 for forming a thin portion is formed on the electroformed support substrate 71 as shown in (a) of the figure, and a portion corresponding to the gap between the thick portions as shown in (b) of FIG. By forming a resist pattern 73 and performing nickel electroforming, for example, nickel is deposited and deposited on the first layer 72 to form a nickel layer 74 as shown in FIG. By continuing the casting, as shown in (d) of the figure, when the nickel layer 74 grows until it protrudes from the window, the edge effect enlarges also in the surface direction of the resist pattern 73 and an overhang portion 74a is generated. If this process is continued, the nickel layer 74 further extends in the thickness direction and the planar direction as shown in FIG. 5E, and after the electroforming is completed at a predetermined growth stage, the resist pattern 73 is formed. By removing the diaphragm, as shown in (f) of the figure, a diaphragm having an island-shaped thick portion with a bowl-shaped cross section surrounded by the recess 75 is obtained.

Further, a configuration in which the member of the thin portion 31 shown in FIG. 1 is a resin layer and the members of the convex portion 32 and the thick portion 33 are metal layers is also conceivable. As a result, the rigidity of the thin-walled portion 31 is lower than that of the diaphragm formed of Ni, so that the displacement efficiency of the piezoelectric element is not hindered. As the metal member, Ni, 42 alloy, and stainless steel are conceivable in the present embodiment. Further, by forming a metal film such as SiO ₂ or Ti on the surface, there is no concern about moisture permeation of the liquid. When the liquid chamber substrate 10 is a metal, the bonding strength between the resin layer and the metal is higher than that between the metals.

  Furthermore, the resin layer may be a rolled film. As a result, even if the thickness is reduced, it is possible to provide a highly reliable product with almost no defects such as pinholes.

In addition, it is also conceivable to perform a process that shows affinity for the adhesive in the bonding region between the diaphragm 30 and the drive unit 42. Further, it is conceivable to form a hydroxyl group or a SiO ₂ thin film layer as a treatment showing affinity. The SiO ₂ thin film layer is formed by a method that can be formed at a temperature that is relatively not heated, that is, a temperature that does not cause thermal influence on the members of the diaphragm 30. Specifically, it can be said that sputtering, ion beam vapor deposition, ion plating, CVD (chemical vapor deposition), P-CVD (plasma vapor deposition) and the like are suitable. After sputtering of Si, the sputtered film is subjected to O ₂ treatment to generate a SiO ₂ film. From the viewpoint of process time and material cost, it is advantageous to set the thickness of the SiO ₂ thin film layer to the minimum necessary thickness within a range in which adhesion can be secured. The thickness of the SiO ₂ film is used in the range of 10 to 2000 mm. As for the water repellent treatment, a water repellent film is formed by a known method such as plating film or water repellent coating. As a water repellent treatment method, a spin coater, a roll coater, a screen printing, a spray coater, or the like can be used. In addition, a method of forming a film by vacuum deposition is also used. When this method is used, the adhesion of the water-repellent film is improved. The thickness of the thin portion is 2 to 10 μm. Moreover, the length of the thin part area | region of a liquid chamber short side direction is 10-70 micrometers.

  In addition, polyphenylene sulfide (PPS) resin is used as the resin layer, but other stretchable polymer materials such as polyimide (PI) resin, polyetherimide (PEI) resin, polyamidoimide (PAI) resin, polybaraban Acid (PPA) resin, Borisulphone (PSF) resin, Polyethersulfone (PES) resin, Polyetherketone (PEK) resin, Polyetheretherketone (PEEK) resin, Polyolefin (APO) resin, Polyethylene naphthalate (PEN) Resins, aramid resins, polypropylene resins, vinylidene chloride resins, polycarbonate resins and the like can also be used.

  FIG. 6 is a cross-sectional view showing another configuration of a liquid discharge head according to another embodiment of the present invention. According to the liquid discharge head of the present embodiment, the members of the frame 60 are formed of two or more members having different thermal conductivities, the heater 80 is provided to control the viscosity of the liquid, and the common liquid chamber The member forming the common liquid chamber uses the high thermal conductivity member 81 having high thermal conductivity in order to heat and retain the liquid in which 13 is accumulated. Further, the outer peripheral portion of the frame 60 close to the driving means is formed by a low thermal conductivity member 82. Moreover, as shown in FIG. 7, the heater 80 and the low heat conductive member 82 may contact | connect. Further, as shown in FIG. 8, the entire outer peripheral portion of the frame 60 is covered with the low thermal conductive member 82, so that the electric control portion 83 can be joined to increase the density of the head. Further, as shown in FIG. 9, a flow path portion from the common liquid chamber 13 to the liquid supply port 34 may serve as a fluid resistance portion 84. Furthermore, if there is a fluid resistance in front of the common liquid chamber, the pressure wave generated on the individual liquid chamber side will not propagate to the common liquid chamber, and image disturbance due to irregular residual pressure waves of the liquid in the common liquid chamber will be prevented. be able to. Further, as shown in FIG. 10, a filter 85 may be installed in a flow path portion from the common liquid chamber 13 to the liquid supply port 34. This filter 85 prevents foreign matter from entering the flow path and prevents nozzle clogging. Further, as the material for the filter 85, a metal material or resin material such as stainless steel or Ni is used. Furthermore, as shown in FIG. 11, a damper 86 for reducing pressure is formed in the member of the frame 60, and the damper 86 can absorb pressure waves generated in the common liquid chamber and liquid inertia due to liquid supply. Become. As the material of the damper, a metal material of stainless steel or Ni or a thin film of resin material is used. A metal film may be formed on the resin member. Further, if the member of the frame 60 is a member having higher rigidity than the flow path unit, it is possible to correct the warpage and deformation of the flow path unit. With this configuration, a highly reliable and small liquid discharge head can be provided. 6 to 11, the members are joined to each other by an adhesive although not shown.

  As for the members of the frame 60 of the present embodiment, the high heat transfer member 81 is a metal member such as stainless steel, Ni, 42 alloy and Si, and the low heat transfer member 82 is a resin member such as epoxy resin, PPS, PES and LCP. It is possible to use it. Moreover, the member which uses the additive for the resin member is also considered.

  Further, not only the piezoelectric direction of the laminated piezoelectric element 40 as the driving means shown in the present embodiment is the d33 direction, but also the piezoelectric direction of the laminated piezoelectric element 40 is the d31 direction as shown in FIGS. The effect of the present invention is not adversely affected. Regarding the joining of the laminated piezoelectric element 40 as the driving means in the d31 direction and the frame 60, the joining is performed by using the low thermal conductive adhesive 87 so that heat transfer does not occur, or the low thermal conductive member 82 is used as a base member. It is possible.

  The ink jet head that can be used in the present invention may be an edge shooter type in which the shape from the ink flow path to the discharge port is linear, or a side shooter type in which the direction of the ink flow path and the direction of the discharge port are different. It may be.

  Next, an example of the image forming apparatus according to the present invention provided with the liquid ejection head or the droplet ejection apparatus according to the present invention will be described with reference to FIGS. FIG. 14 is a side view showing the overall configuration of the image forming apparatus according to the present invention, and FIG. 15 is a plan view showing the main configuration of the image forming apparatus according to the present invention.

  An image forming apparatus 100 according to the present invention holds a carriage 103 slidably in a main scanning direction by a guide rod 101 and a guide rail 102 that are horizontally mounted on left and right side plates (not shown). It moves and scans in the direction indicated by the arrow (main scanning direction) in FIG. For example, a recording head 106 including four liquid discharge heads for discharging liquid droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) is disposed on the carriage 103. The outlets are arranged in a direction crossing the main scanning direction, and are mounted with the droplet discharge direction facing downward. As the liquid discharge head constituting the recording head 106, a liquid ejection head using a piezoelectric actuator such as a piezoelectric element is used.

  Also, the carriage 103 is equipped with a sub-tank 107 for each color for supplying each color liquid to the recording head 106. The sub tank 107 is replenished with liquid from the ink cartridge of the present invention, which is the main tank, via a liquid supply tube (not shown). In this embodiment, the sub-tank 107 and the recording head 106 constitute a liquid droplet ejection device. However, the recording head 106 may be composed of the liquid ejection head according to the present invention, and the sub-tank 107 may be provided separately. Alternatively, the ink cartridge of the present invention can be mounted without using a sub tank.

  On the other hand, as a paper feeding unit for feeding the paper 110 stacked on the paper stacking unit (pressure plate) 109 such as the paper feeding cassette 108, a half-moon roller that separates and feeds the paper 110 one by one from the paper stacking unit 109. A sheet feeding roller 111 and a separation pad 112 made of a material having a large friction coefficient are provided opposite to the sheet feeding roller 111, and the separation pad 112 is urged toward the sheet feeding roller 111 side.

  Then, as a transport unit for transporting the paper 110 fed from such a paper feed unit below the recording head 106, a transport belt 113 for transporting the paper 110 by electrostatic adsorption, and a paper feed The counter roller 115 for transporting the paper 110 sent from the section via the guide 114 between the transport belt 113 and the paper 110 sent substantially vertically upward is changed by about 90 ° to be on the transport belt 113. A conveyance guide 116 for following the above and a tip pressure roller 118 urged toward the conveyance belt 113 by a pressing member 117. In addition, a charging roller 119 that is a charging unit for charging the surface of the conveyance belt 113 is provided.

  Here, the conveyance belt 113 is an endless belt, is stretched between the conveyance roller 120 and the tension roller 121, and is conveyed from the sub-scanning motor 122 via the timing belt 123 and the timing roller 124. Is rotated to rotate in the belt conveyance direction (sub-scanning direction) in FIG. A guide member 125 is disposed on the back side of the conveyor belt 113 in correspondence with the image forming area formed by the recording head 106.

  Further, as shown in FIG. 14, a slit disk 125 is attached to the shaft of the conveying roller 120, and the sensor 126 of FIG. 20 for detecting the slit of the slit disk 125 is provided. The encoder 127 is constituted by the sensor 125 and the sensor 126. Further, the charging roller 119 is arranged so as to come into contact with the surface layer of the conveyor belt 113 and rotate following the rotation of the conveyor belt 113, and 2.5N is applied to both ends of the shaft as a pressing force. Further, as shown in FIG. 15, an encoder scale 128 having slits is provided on the front side of the carriage 103, and an encoder sensor comprising a transmissive photosensor that detects the slits of the encoder scale 128 on the front side of the carriage 103. The encoder 130 for detecting the position of the carriage 103 in the main scanning direction (position with respect to the home position) is configured.

  Further, as a paper discharge unit for discharging the paper 110 recorded by the recording head 106, a separation unit for separating the paper 110 from the conveying belt 113, a paper discharge roller 131 and a paper discharge roller 132, and paper discharge A paper discharge tray 133 for stocking the paper 110 to be stored.

  A double-sided paper feeding unit 134 is detachably attached to the back. The double-sided paper feeding unit 134 takes in the paper 110 returned by the reverse rotation of the transport belt 113, reverses it, and feeds it again between the counter roller 115 and the transport belt 113.

  In the image forming apparatus 100 of the present invention having such a configuration, the sheets 110 are separated and fed one by one from the sheet feeding unit, and the sheet 110 fed substantially vertically upward is guided by the guide 114 and is conveyed by the conveyance belt. 113 and the counter roller 115 are sandwiched and conveyed. Further, the leading end is guided by the conveying guide 116 and pressed against the conveying belt 113 by the leading end pressure roller 118, and the conveying direction is changed by approximately 90 °. At this time, a positive output and a negative output are alternately repeated from the high voltage power source to the charging roller 119 by a control circuit (not shown), that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 113 alternates, that is, a loop In the sub-scanning direction, which is the direction, plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 110 is fed onto the conveyance belt 113 charged with this plus and minus alternately, the sheet 110 is attracted to the conveyance belt 113 by electrostatic force, and the sheet 110 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 113. Is done.

  Therefore, by driving the recording head 106 according to the image signal while moving the carriage 103, droplets are ejected onto the stopped sheet 110 to record one line, and after the sheet 110 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 110 reaches the recording area, the recording operation is finished, and the paper 110 is discharged onto the paper discharge tray 133.

  In the case of double-sided printing, when recording on the front surface (surface to be printed first) is completed, the recording belt 110 is fed into the double-sided paper feeding unit 134 by rotating the conveyor belt 113 in the reverse direction. The paper 110 is reversed (with the back surface being the printing surface), and is fed again between the counter roller 115 and the conveyor belt 113. The timing is controlled, and the sheet 110 is conveyed onto the conveyor bell 113 as described above. Then, after recording on the back surface, the paper is discharged onto the paper discharge tray 133.

  Note that the image forming apparatus according to the present invention can also be applied to a printer, a facsimile machine, a copying machine, a multi-function machine thereof, and the like. Further, the present invention can also be applied to a liquid discharge head or a droplet discharge device that discharges a liquid other than ink, such as a DNA sample, a resist, or a pattern material, or an image forming apparatus that includes these.

  Further, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications and substitutions are possible as long as the description is within the scope of the claims.

Japanese Patent No. 2,831,778 JP 2005-254666 A

Claims (9)

A liquid chamber unit in which a nozzle substrate having a nozzle for discharging a liquid, a liquid chamber for storing a liquid communicating with each nozzle including a flow path, and a diaphragm forming at least a part of a wall surface of the liquid chamber are joined. Driving means for generating pressure to pressurize the liquid in the liquid chamber, a frame member that supports the liquid chamber unit and has a common liquid chamber, and heating means for heating the liquid discharged to the frame member In a liquid discharge head having
The frame member is formed from a plurality of types of members having different thermal conductivities,
A liquid ejection head, wherein a portion of the frame member provided with the heating means is formed of a high heat conductive member, and a portion formed of a low heat conductive member is provided on the driving means side of the high heat conductive member.   The liquid discharge head according to claim 1, wherein an outer peripheral portion of the high heat conductive member is formed of a low heat conductive member.   3. The liquid discharge head according to claim 1, wherein a flow path on a frame member side for supplying a liquid from the common liquid chamber to the liquid chamber of the liquid chamber unit serves as a fluid resistance portion.   The liquid discharge head according to claim 1, wherein a filter is provided in a flow path on a frame member side that supplies liquid from the common liquid chamber to the liquid chamber of the liquid chamber unit.   5. The liquid discharge head according to claim 1, wherein a damper is provided on the frame member that supplies liquid from the common liquid chamber to the liquid chamber of the liquid chamber unit.   The liquid ejection head according to claim 1, wherein the frame member is formed of a member having higher rigidity than the flow path unit.   The liquid discharge head according to claim 1, wherein the machining for forming the liquid chamber substrate is press working.   A head cartridge 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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