JP4446708B2 - Droplet discharge head, liquid discharge apparatus, and image forming apparatus - Google Patents

Description

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

  2. Description of the Related Art As an image forming apparatus such as a printer, a facsimile, a copying apparatus, a printer / fax / copier multifunction machine, an ink jet recording apparatus is known. An ink jet recording apparatus ejects ink droplets from an ink recording head onto a recording medium (also referred to as paper, recording medium, recording paper, etc.) to form an image (recording, printing, printing, and printing are used interchangeably). .), High-definition images can be recorded at high speed, running cost is low, noise is low, and it is easy to record color images using multi-colored inks. It has the advantages such as.

  A droplet discharge head used in such an ink jet recording apparatus generally communicates with an independent pressure chamber for each nozzle that discharges ink droplets as droplets, and generates pressure in the pressure chamber. The ink inside is ejected from the nozzle. A common liquid chamber communicates with each pressure chamber via an ink supply path, and the ink supplied from the ink supply port to the common liquid chamber is distributed to each pressure chamber.

For example, as disclosed in Patent Literature 1 and Patent Literature 2, an ink supply port for supplying ink from the outside to a common liquid chamber is formed in a droplet discharge head using a multilayer piezoelectric element. Further, the piezoelectric element unit is housed in the head case, and electrical wiring to the piezoelectric element unit is performed from the direction facing the nozzle surface through the opening provided in the head case. For this reason, the piezoelectric element storage part of the head case has a cylindrical shape that is largely open from the nozzle surface side toward the opposing direction.
JP 2003-89203 A JP 2003-39672 A

  For example, as shown in FIG. 9, the conventional droplet discharge head as described above has a pressure at which a flow path plate 501, a vibration plate 502, and a nozzle plate 503 are stacked and joined to communicate with a nozzle 504 that discharges droplets. A flow path unit including the chamber 505 is configured, and in this flow path unit, two nozzle rows in which the nozzles 504 are arranged are provided. On the other hand, a piezoelectric element unit composed of laminated piezoelectric elements 511 bonded to the substrate 510 is bonded to the outer surface side of the diaphragm 502.

  A head case (frame member) 513 is joined to the peripheral side of the diaphragm 502. In the head case 513, two common liquid chambers 508 corresponding to each nozzle row for supplying ink to the plurality of pressure chambers 505 corresponding to each nozzle row through the holes 502a of the diaphragm 502 are formed. An ink supply port 509 for supplying ink from the outside to the common liquid chamber 508 is formed. The head case 513 is formed with an opening 515 serving as a storage portion for storing the piezoelectric element unit, and an electrical wiring (FPC) 516 to the piezoelectric element 511 is connected through the opening 515.

  As described above, the portion of the head case 513 that accommodates the piezoelectric element unit has a cross-sectional structure that opens in the opposite direction to the nozzle side. Among them, on the nozzle side, since the diaphragm 502 of the flow path unit is joined, the head case 513 forms a cross section closed by the flow path unit, but in the opposite direction, the wiring from the piezoelectric element 511 is used. A cross-sectional structure opened at an opening 515 for taking out a certain FPC 516 is obtained.

  Therefore, it is difficult for the head case 513 to increase the rigidity in the direction indicated by the arrow 517 in FIG. 9 (the direction orthogonal to the nozzle arrangement direction). As a result, when the head is driven by the piezoelectric element 511, the vibration is also transmitted to the head case 513, and deformation and resonance in the direction of the arrow 517 occur, resulting in pressure fluctuations in the ink supply path, and stable droplet ejection. There arises a problem that the performance is lowered.

  The present invention has been made in view of the above problems, and includes a droplet discharge head and a droplet discharge device capable of performing stable droplet discharge, and a high-quality image including these droplet discharge head or droplet discharge device. An object of the present invention is to provide an image forming apparatus capable of recording an image.

In order to solve the above problems, a liquid droplet ejection head according to the present invention includes:
A plurality of nozzle rows each having a plurality of nozzles for discharging droplets, a pressure chamber communicating with the nozzles, and a plurality of driving means for pressurizing liquid in the pressurizing chamber, each having a plurality of pressures In a droplet discharge head having a plurality of common liquid chambers corresponding to the plurality of nozzle rows for supplying a liquid to a chamber,
Supplying liquid to each common liquid chamber from the side opposite to the surface having the nozzle, having a plurality of liquid supply ports fitted with elastic bodies ,
The liquid supply port is provided on both sides of the drive means,
Here the liquid supply port with each other sandwiching the driving means is restrained from the nozzle in a direction parallel to the surface of a member to be fitted with no gap through said elastic member in a direction parallel to the nozzle surface to the liquid supply port Thus, the member to be fitted can be a liquid supply means to the common liquid chamber. Further, the liquid supply means can be configured to include a negative pressure generating mechanism.

The droplet discharge device according to the present invention is
A plurality of nozzle rows each having a plurality of nozzles for discharging droplets, a pressure chamber communicating with the nozzles, and a plurality of driving means for pressurizing liquid in the pressurizing chamber, each having a plurality of pressures A droplet discharge head having a plurality of common liquid chambers corresponding to the plurality of nozzle rows for supplying a liquid to the chamber, and a liquid supply means for supplying the liquid to each common liquid chamber of the droplet discharge head In the droplet discharge device
Wherein the liquid droplet ejection head for supplying liquid to the common liquid chamber from the liquid supply means on the side opposite to the surface having the nozzle, having a plurality of liquid supply ports elastic body is fitted,
The liquid supply port is provided on both sides of the driving means,
Wherein said liquid supply port with each other sandwiching the driving means is restrained from the nozzle in a direction parallel to the surface by the liquid supply means to be fitted with no gap through said elastic member in a direction parallel to the nozzle surface to the liquid supply port It was set as the structure.

  The image forming apparatus according to the present invention includes the droplet discharge head according to the present invention or the droplet discharge apparatus according to the present invention.

The liquid droplet ejection head according to the present invention has a plurality of liquid supply ports fitted with elastic bodies for supplying liquid to each common liquid chamber from the side opposite to the surface having the nozzles, and the liquid supply ports are driven. provided on both sides of means, liquid supply port with each other across the drive means, from the nozzle in a direction parallel to the surface of a member to be fitted without a gap in a direction parallel to the nozzle surface through the elastic body to the liquid supply port Since the configuration is restricted, it is possible to perform stable droplet discharge while suppressing vibration.

According to the droplet discharge device of the present invention , the elastic body that includes the droplet discharge head and supplies the liquid to each common liquid chamber from the liquid supply unit on the side opposite to the surface having the nozzle is provided on the droplet discharge head. a plurality of liquid supply ports fitted, parallel liquid supply port is provided on both sides of the driving means, the liquid supply port with each other sandwiching the drive means includes a nozzle surface through the elastic body to the liquid supply port Since the configuration is such that the liquid supply means that fits without any gap in the direction is restrained from the direction parallel to the nozzle surface, it is possible to suppress the vibration and perform stable droplet discharge.

  According to the image forming apparatus according to the present invention, since the liquid droplet ejection head according to the present invention or the liquid droplet ejection apparatus according to the present invention is provided, stable droplet ejection can be performed and image quality is improved. .

Embodiments of the present invention will be described below with reference to the accompanying drawings.
An embodiment of a droplet discharge head according to the present invention will be described with reference to FIGS. 1 is an exploded perspective view of the head, FIG. 2 is a sectional view of the head, and FIG. 3 is a plan view of a nozzle plate of the head.

  The droplet discharge head includes a nozzle plate 1 formed by, for example, Ni electroforming, in which a plurality of nozzle rows 2A and 2B configured by arranging a plurality of nozzles 2 that discharge droplets in a straight line are formed. A pressure chamber 6 that communicates with the nozzle 2 of the nozzle plate 1 and a flow path plate 4 that forms an ink supply path 7 that supplies ink to the pressure chamber 6 and a vibration plate 5 that is manufactured by, for example, Ni electroforming are laminated and joined. ing.

  The flow path plate 4 includes, for example, a recess or pressure chamber 6 that forms the pressure chamber 6 and the ink supply path 7 on the vibration plate 5 side by anisotropically etching a Si single crystal substrate having a (110) plane orientation. A communication pipe (nozzle communication path) that communicates with the nozzle 2 is formed. The pressure chamber 6 is supplied with liquid ink from the common liquid chamber 8 through a supply hole 5 a formed in the diaphragm 5.

  Further, the piezoelectric element 10 as a driving means (pressure converting means, actuator means) for generating pressure for pressurizing the ink in the pressure chamber 6 corresponds to the nozzle 2 rows (nozzle rows 2A, 2B). The joint is arranged on the top. Specifically, the piezoelectric element 10 is formed by processing two piezoelectric elements into a comb-like groove so as to correspond to each of the nozzles 2.

  The piezoelectric elements 10 and 10 are assembled so as to come into contact with the diaphragm 5 in a state in which the FPCs 20 and 20 for driving are joined. The diaphragm 5 is deformed by the displacement of the piezoelectric element 10, and the internal ink is ejected as droplets from the nozzle 2 due to the pressure increase inside the pressure chamber 6.

  Ink is distributed and supplied to the supply hole 5a of the vibration plate 5 from the common liquid chamber 8 formed by the frame member 15 which is also a structural member of the common liquid chamber. The frame member 15 is formed of a thermosetting epoxy resin containing silica powder.

  The frame member 15 is supplied with ink from an external liquid supply means, for example, an ink cartridge or a sub tank, to the common liquid chambers 8 and 8 corresponding to the nozzle rows 2A and 2B from the side opposite to the surface having the nozzles 2. The liquid supply ports 9 and 9 are formed, and an opening 16 for accommodating the piezoelectric unit including the piezoelectric element 10 and the base 11 is formed. A head cover 17 that covers the peripheral edge of the nozzle surface of the nozzle plate 3 is attached to the outer peripheral surface of the frame member 15 on the nozzle plate 3 side.

The liquid supply ports 9 and 9 of the frame member 15 are provided on both sides of the piezoelectric element 10 that is a driving means, and a portion that forms at least a part of the liquid supply ports 9 and 9 (this It is referred to as a “liquid supply port”.) A fixing plate 21 is provided which is a member fitted to the liquid supply ports 19 and 19 for restraining 19 and 19 from a direction parallel to the nozzle surface.

  The fixing plate 21 has through holes 22 and 22 into which the liquid supply ports 19 and 19 of the frame member 15 are inserted. The liquid supply port 19 is inserted into the through holes 22 and 22 of the fixing plate 21 with the spacers 23 and 23 and the O-rings 24 and 24 fitted on the outside of the liquid supply ports 19 and 19 of the frame member 15. , 19 are inserted to restrain the liquid supply ports 19, 19 from being parallel to the nozzle surface and fixed to the fixed plate 21. In addition, it replaces with the O-rings 24 and 24, and another elastic member or a sealing member can also be used.

  As described above, the liquid supply ports 19 and 19 of the frame member 15 are constrained by the fixing plate 21 via the O-rings 24 and 24 in a direction parallel to the nozzle surface. Although it has an open and open cross-sectional shape, a cross section is formed in which both sides are closed by the flow path plate 3 and the fixed plate 21.

  As a result, the rigidity of the frame member 15 can be ensured, the droplet discharge can be prevented from becoming unstable due to insufficient rigidity, and stable droplet discharge can be performed.

  Next, an embodiment of a droplet discharge device according to the present invention will be described with reference to FIGS. 4 is an exploded perspective view of the discharge device, FIG. 5 is a partially broken perspective view of the discharge device in an assembled state, and FIG. 6 is a cross-sectional view of the discharge device.

  This droplet discharge device includes a droplet discharge head 31 and a sub tank 32 that is a liquid supply means for supplying ink, which is a liquid, to the droplet discharge head 31. Since the droplet discharge head 31 is the same as that of the embodiment of the droplet discharge head according to the present invention except for the fixed plate 21, the same reference numerals are given and description thereof is omitted.

  In this droplet discharge device, the liquid supply ports 19 and 19 of the frame member 15 of the droplet discharge head 31 are restrained by the sub tank 32 from a direction parallel to the nozzle surface. That is, the holes (34, 34) for inserting the liquid supply port portions (19, 19) of the frame member (15) are provided in the housing (case) 33 of the sub tank (32), and the spacers (23, 23) are provided outside the liquid supply port portions (19, 19) of the frame member (15). 23 and the O-rings 24 and 24 are fitted, and the liquid supply ports 19 and 19 are inserted into the holes 34 and 34 of the sub tank 32 so that the liquid supply ports 19 and 19 are parallel to the nozzle surface. It is restrained from any direction and fixed to the sub tank 32.

  The sub tank 32 houses a negative pressure generating mechanism using a porous body, a spring, and a flexible film member (not shown) in the case 33.

  As described above, the liquid supply ports 19 and 19 are constrained by the sub tank 32 via the O-rings 24 and 24 in a direction parallel to the nozzle surface. Although it has a shape, a closed cross section is formed by the flow path plate 3 and the housing 33 of the sub tank 32.

  As a result, the rigidity of the frame member 15 can be ensured, the droplet discharge can be prevented from becoming unstable due to insufficient rigidity, and stable droplet discharge can be performed.

  Next, an example of the image forming apparatus according to the present invention provided with the liquid droplet ejection head or the liquid droplet ejection apparatus according to the present invention will be described with reference to FIGS. 8 is an explanatory side view for explaining the overall configuration of the apparatus, and FIG. 9 is an explanatory plan view of a main part of the apparatus.

  In this image forming apparatus, a carriage 103 is slidably held in a main scanning direction by a guide rod 101 and a guide rail 102 which are horizontally mounted on left and right side plates (not shown), and a timing belt 105 is slid by a main scanning motor 104. 9 to move and scan in the direction indicated by the arrow (main scanning direction) in FIG.

  For example, the carriage 103 includes a plurality of recording heads 107 including four droplet ejection heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The ink discharge ports are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet discharge direction facing downward. In addition, as a droplet discharge head constituting the recording head 107, a droplet discharge head using a piezoelectric actuator such as a piezoelectric element is used.

  The carriage 103 is also equipped with a sub-tank 108 for each color for supplying each color ink to the recording head 107. Ink is supplied to the sub tank 108 from a main tank (ink cartridge) through an ink supply tube (not shown).

  In this embodiment, the sub-tank 108 and the recording head 107 constitute the liquid droplet ejection apparatus according to the present invention. However, the recording head 107 is composed of the liquid droplet ejection head according to the present invention, and the sub-tank 108 is separately provided. Alternatively, the ink cartridge can be mounted without using a sub tank.

  On the other hand, as a paper feeding unit for feeding paper 112 stacked on a paper stacking unit (pressure plate) 111 such as a paper feeding cassette 110, a half-moon roller (separately feeding paper 112 one by one from the paper stacking unit 111) A separation pad 114 made of a material having a large friction coefficient is provided opposite to the sheet feeding roller 113 and the sheet feeding roller 113, and the separation pad 114 is urged toward the sheet feeding roller 113 side.

  As a transport unit for transporting the paper 112 fed from the paper feed unit below the recording head 107, a transport belt 121 for electrostatically attracting and transporting the paper 112, and a paper feed unit A counter roller 122 for transporting the paper 112 fed through the guide 115 while sandwiching it between the transport belt 121 and the paper 112 fed substantially vertically upward is changed by about 90 ° and copied on the transport belt 121. A conveying guide 123 for adjusting the pressure and a tip pressure roller 125 urged toward the conveying belt 121 by a pressing member 124. In addition, a charging roller 126 that is a charging unit for charging the surface of the conveyance belt 121 is provided.

  Here, the conveyance belt 121 is an endless belt, is stretched between the conveyance roller 127 and the tension roller 128, and the conveyance roller 127 is rotated from the sub-scanning motor 131 via the timing belt 132 and the timing roller 133. By doing so, it is configured to circulate in the belt conveyance direction (sub-scanning direction) of FIG. A guide member 129 is disposed on the back side of the conveyance belt 121 in correspondence with the image forming area formed by the recording head 107.

  As shown in FIG. 9, a slit disk 134 is attached to the shaft of the transport roller 127, and a sensor 135 for detecting the slit of the slit disk 134 is provided. An encoder 136 is configured.

  The charging roller 126 is arranged so as to contact the surface layer of the conveyor belt 121 and rotate following the rotation of the conveyor belt 121, and applies 2.5N to both ends of the shaft as a pressing force.

  Further, as shown in FIG. 8, an encoder scale 142 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 142 on the front side of the carriage 103. The encoder 144 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 112 recorded by the recording head 107, a separation unit for separating the paper 112 from the conveying belt 121, a paper discharge roller 152 and a paper discharge roller 153, and paper discharge A paper discharge tray 154 for stocking the paper 112 to be printed.

  A double-sided paper feeding unit 161 is detachably attached to the back. The double-sided paper feeding unit 161 takes in the paper 112 returned by the reverse rotation of the transport belt 121, reverses it, and feeds it again between the counter roller 22 and the transport belt 121.

  In the image forming apparatus configured as described above, the sheets 112 are separated and fed one by one from the sheet feeding unit, and the sheet 112 fed substantially vertically upward is guided by the guide 115, and includes the conveyance belt 121 and the counter roller 122. The leading end is guided by the conveying guide 123 and pressed against the conveying belt 121 by the leading end pressure roller 125, and the conveying direction is changed by approximately 90 °.

  At this time, a positive voltage output and a negative output are alternately repeated from the high voltage power supply to the charging roller 126 by a control circuit (not shown), that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 121 alternates, that is, In the sub-scanning direction, which is the circumferential direction, plus and minus are alternately charged in a band shape with a predetermined width. When the paper 112 is fed onto the conveyance belt 121 charged alternately with plus and minus, the paper 112 is attracted to the conveyance belt 121 by electrostatic force, and the paper 112 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 121. Is done.

  Therefore, by driving the recording head 107 according to the image signal while moving the carriage 103, ink droplets are ejected onto the stopped paper 112 to record one line, and after the paper 112 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 112 has reached the recording area, the recording operation is finished, and the paper 112 is discharged onto the paper discharge tray 154.

  In the case of double-sided printing, when recording on the front surface (surface to be printed first) is completed, the recording belt 112 is fed into the double-sided paper feeding unit 161 by rotating the conveyor belt 121 in the reverse direction. The paper 112 is reversed (with the back surface being the printing surface), and is fed again between the counter roller 122 and the conveyor belt 121. The timing is controlled, and the sheet is conveyed onto the conveyor bell 121 as described above. Then, after recording on the back surface, the paper is discharged onto the paper discharge tray 54.

  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 droplet 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.

FIG. 3 is an exploded perspective view of a droplet discharge head according to the present invention. It is sectional explanatory drawing of the head. It is a plane explanatory view of the nozzle plate of the head. It is a disassembled perspective explanatory drawing of the droplet discharge apparatus which concerns on this invention. It is a partially broken perspective explanatory view in the assembly state of the device. It is a section explanatory view of the device. 1 is an explanatory diagram illustrating an overall configuration of an image forming apparatus according to the present invention. FIG. 2 is an explanatory plan view of a main part of the image forming apparatus. It is a cross-sectional explanatory view of a conventional droplet discharge head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Nozzle plate 2 ... Nozzle 2A, 2B ... Nozzle row 4 ... Flow path plate 5 ... Vibration plate 6 ... Pressure chamber 8 ... Common liquid chamber 9 ... Liquid supply port 10 ... Piezoelectric element 11 ... Base substrate 15 ... Frame member 16 ... Opening 19 ... Liquid supply port 20 ... FPC
DESCRIPTION OF SYMBOLS 21 ... Fixed plate 23 ... Spacer 24 ... O-ring 31 ... Droplet discharge head 32 ... Sub tank (liquid supply means)
103 ... Carriage 107 ... Recording head 108 ... Sub tank

Claims (5)

A plurality of nozzle rows each including a plurality of nozzles for discharging droplets, a pressure chamber communicating with the nozzles, and a plurality of driving means for pressurizing liquid in the pressurizing chamber, each having a plurality of pressures In a droplet discharge head having a plurality of common liquid chambers corresponding to the plurality of nozzle rows for supplying a liquid to a chamber,
Supplying liquid to each common liquid chamber from the side opposite to the surface having the nozzle, having a plurality of liquid supply ports fitted with elastic bodies ,
The liquid supply port is provided on both sides of the drive means,
Said liquid supply port with each other sandwiching the driving means is restrained from the nozzle in a direction parallel to the surface of a member to be fitted with no gap through said elastic member in a direction parallel to the nozzle surface to the liquid supply port A droplet discharge head characterized by the above.   The droplet discharge head according to claim 1, wherein the fitting member is a liquid supply unit to the common liquid chamber. The droplet discharge head according to claim 2, wherein the liquid supply unit includes a negative pressure generating mechanism. A plurality of nozzle rows each having a plurality of nozzles for discharging droplets, a pressure chamber communicating with the nozzles, and a plurality of driving means for pressurizing liquid in the pressurizing chamber, each having a plurality of pressures A droplet discharge head having a plurality of common liquid chambers corresponding to the plurality of nozzle rows for supplying a liquid to the chamber, and a liquid supply means for supplying the liquid to each common liquid chamber of the droplet discharge head In the droplet discharge device
The liquid droplet ejection head has a plurality of liquid supply ports fitted with elastic bodies to supply liquid from the liquid supply means to each common liquid chamber on the side opposite to the surface having the nozzle.
The liquid supply port is provided on both sides of the drive means,
Wherein said liquid supply port with each other sandwiching the driving means is restrained from the nozzle in a direction parallel to the surface by the liquid supply means to be fitted with no gap through said elastic member in a direction parallel to the nozzle surface to the liquid supply port A droplet discharge device characterized by comprising:   An image forming apparatus for discharging a droplet to form an image on a recording medium, comprising the droplet discharge head according to any one of claims 1 to 3 or the droplet discharge device according to claim 4. An image forming apparatus.

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