JP5776363B2 - Liquid ejection head and image forming apparatus - Google Patents

Description

  The present invention relates to a liquid discharge head and an image forming apparatus, and more particularly to a liquid discharge head arranged in a state in which droplets are discharged upward in the vertical direction and an image forming apparatus including the liquid discharge head as a recording head.

  As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, a plotter, and a multi-function machine thereof, for example, an ink jet recording apparatus as an image forming apparatus of a liquid discharge recording system using a recording head composed of a liquid discharge head for discharging ink droplets Etc. are known.

  2. Description of the Related Art As a conventional image forming apparatus, an apparatus including a recording head that performs image recording on a lower surface of a recording medium by ejecting ink droplets upward from a nozzle against gravity is known (Patent Document 1).

JP 2001-334121 A

  By the way, when bubbles are mixed in the flow path of the liquid ejection head, ejection failure such as ejection bending of the ejected droplets or inability to eject occurs, and stable droplet ejection cannot be performed, and image quality is deteriorated. become.

  In particular, when the liquid ejection head is disposed in a state in which liquid droplets are ejected in the vertical upward direction as described above, bubbles that enter the common liquid chamber that supplies ink to the individual liquid chambers that communicate with a plurality of nozzles Therefore, there is a problem that the liquid is moved to the individual liquid chamber side by buoyancy, and the flow path on the downstream side of the common liquid chamber is blocked, and discharge failure is likely to occur.

  The present invention has been made in view of the above problems, and prevents bubbles in a recording head that discharges liquid droplets upward in the vertical direction from entering the downstream flow path from the common liquid chamber, thereby stabilizing the image. The purpose is to enable formation.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A liquid discharge head disposed in a state in which droplets are discharged vertically upward;
A plurality of nozzles for discharging droplets;
A plurality of individual liquid chambers in which the plurality of nozzles communicate with each other;
A common liquid chamber for supplying liquid to the plurality of individual liquid chambers,
In the common liquid chamber, at least one of the arrangement direction of the plurality of individual liquid chambers and the direction orthogonal to the arrangement direction, from one end side to the other end side, or from the central part to both end parts side A member having an inclined surface that is inclined linearly or curvedly in a direction increasing in the height direction is disposed,
At least one end side or both end sides of the common liquid chamber in the direction in which the plurality of individual liquid chambers are arranged and in the direction orthogonal to the arrangement direction are air bubbles outside the region where the inlet side of the individual liquid chamber faces. It was set as the structure by which the bubble reservoir which accumulates was provided.

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

According to the liquid ejection head according to the present invention, it is possible to prevent the bubbles definitive recording head for ejecting droplets vertically above enters the downstream channel from the common liquid chamber, to enable stable image formation become.

  According to the image forming apparatus of the present invention, since the liquid ejection head according to the present invention is provided, a high-quality image can be stably formed.

FIG. 2 is a side view illustrating a main part for explaining an example of the image forming apparatus according to the present invention. It is a principal part bottom view similarly seen from the apparatus bottom face side. It is block explanatory drawing with which the outline | summary of the control part of the apparatus is provided. FIG. 2 is an external perspective explanatory view of a liquid discharge head constituting the recording head in the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional explanatory view taken along the X plane of FIG. 4 (a direction orthogonal to the nozzle arrangement direction). FIG. 5 is a schematic cross-sectional explanatory diagram along the Y plane (nozzle arrangement direction) in FIG. 4. FIG. 6 is a schematic cross-sectional explanatory diagram along a direction orthogonal to a nozzle arrangement direction of a liquid discharge head constituting a recording head in a second embodiment of the present invention. It is a typical cross-sectional explanatory drawing which follows a nozzle arrangement direction. FIG. 10 is a schematic cross-sectional explanatory diagram along a direction orthogonal to a nozzle arrangement direction of a liquid discharge head constituting a recording head in a third embodiment of the present invention. It is a typical cross-sectional explanatory drawing which follows a nozzle arrangement direction. FIG. 10 is a schematic cross-sectional explanatory diagram along a nozzle arrangement direction of a liquid discharge head constituting a recording head in a fourth embodiment of the invention. FIG. 6 is a schematic cross-sectional explanatory diagram along a nozzle arrangement direction of a liquid discharge head constituting a recording head in a comparative example.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an image forming apparatus according to the present invention will be described with reference to FIGS. 1 is an explanatory side view of the main part of the image forming apparatus, and FIG. 2 is an explanatory view of the main part bottom as seen from the apparatus bottom side.

  This image forming apparatus is a serial type image forming apparatus, and has an image forming unit 2, a transport mechanism unit 5 and the like inside the apparatus main body, and a sheet as a recording medium from a paper supply unit 4 on the lower side of the apparatus main body. 10, while the paper 10 is transported intermittently in the horizontal direction by the transport mechanism 5, the image forming unit 2 discharges droplets upward in the vertical direction, records a required image, and then discharges the paper. The paper 10 is discharged to the paper discharge tray 7 of the unit 6.

  Here, the image forming unit 2 slidably holds a carriage 23 on which a recording head 24 is mounted with a main guide member 21 and a sub guide member 22 that are horizontally mounted between the left and right side plates 11L and 11R, and a main scanning motor. 25, the moving scanning is performed in the main scanning direction via the timing belt 28 passed between the driving pulley 26 and the driven pulley 27.

  The carriage 23 has recording heads 24a and 24b composed of liquid ejection heads for ejecting ink droplets of each color of yellow (Y), magenta (M), cyan (C), and black (K). As shown, the recording head 24 is arranged in a sub-scanning direction orthogonal to the main scanning direction and a droplet discharge direction is directed upward in the vertical direction.

  The liquid discharge head constituting the recording head 24 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change due to liquid film boiling using an electrothermal conversion element such as a heating resistor, and a metal due to a temperature change. A shape memory alloy actuator using a phase change, an electrostatic actuator using an electrostatic force, or the like provided as pressure generating means for generating a pressure for discharging a droplet can be used. The carriage 23 can also be mounted with a liquid discharge head that discharges a fixing liquid that reacts with the ink to enhance the fixability of the ink.

  The carriage 23 is mounted with a head tank 29 for supplying ink of each color corresponding to each nozzle row of the recording head 24. The head tank 29 is detachably attached to the apparatus main body. Ink is supplied from each color ink cartridge (main tank). Note that since the recording head 24 has a droplet discharge direction in the vertical upward direction, it is not always necessary to form a negative pressure in order to prevent liquid dripping. Here, the head tank 29 is a simple buffer tank.

  Further, an encoder scale 121 having a predetermined pattern is stretched between the both side plates 11L and 11R along the main scanning direction of the carriage 23, and the carriage 23 is composed of a transmission type photosensor that reads the pattern of the encoder scale 121. An encoder sensor 122 is provided, and the encoder scale 121 and the encoder sensor 122 constitute a linear encoder (main scanning encoder) 123 that detects the movement of the carriage 23.

  A maintenance / recovery mechanism 9 for maintaining and recovering the state of the nozzles of the recording head 24 is disposed in a non-printing area on one side in the scanning direction of the carriage 23. The maintenance / recovery mechanism 9 includes caps 92a and 92b for capping each nozzle surface of the recording head 24 (referred to as “cap 92” when not distinguished) and a wiper member (wiper blade) for wiping the nozzle surface. 93, and an empty discharge receiver 94 for receiving droplets when performing empty discharge for discharging droplets that do not contribute to recording in order to discharge the thickened recording liquid.

  The paper feed unit 4 separates the paper 10 in the paper feed tray 41 one by one by a paper feed roller (half moon roller) 43 and a separation pad 44 and feeds the paper 10 into the apparatus main body, along the transport guide member 45, After being fed between the pair of registration rollers 46 and 47 on the upstream side of the transport mechanism unit 5, it is attracted to and transported by the transport belt 51 of the transport mechanism unit 5. A paper detection sensor 49 for detecting the paper 10 is disposed upstream of the registration roller pairs 46 and 47.

  The conveyance mechanism unit 5 includes an endless conveyance belt 51 that is stretched between a conveyance roller 52 that is a driving roller and a driven roller 53, a charging roller 54 that charges the conveyance belt 51, and the image forming unit 2. A platen member (not shown) that maintains the flatness of the conveyor belt 51 is provided at a portion facing the plate.

  The conveyance belt 51 rotates in the belt conveyance direction (sub-scanning direction, paper conveyance direction) when the conveyance roller 52 is rotationally driven by the sub-scanning motor 151 via the timing belt 152 and the timing pulley 153.

  In addition, a code wheel 154 is attached to the shaft 52 a of the transport roller 52, and an encoder sensor 155 including a transmission type photo sensor for detecting a pattern formed on the code wheel 154 is provided. A rotary encoder (sub-scanning encoder) 156 that detects the amount and position of movement of the conveyor belt 51 is configured.

  The paper discharge unit 6 includes a separation claw 61 that separates the paper 10 on which an image is recorded from the transport belt 51, a paper discharge transport roller 62, and a spur 63. The paper 10 on which the image is formed is discharged to the paper discharge roller 62 and Paper is discharged from between the spurs 63 onto the paper discharge tray 7.

  In this image forming apparatus configured as described above, the sheets 10 are separated and fed one by one from the sheet feeding tray 41 of the sheet feeding unit 4, and the sheet 10 is electrostatically adsorbed to the charged conveying belt 51, thereby conveying the conveying belt. The paper 10 is conveyed in the horizontal direction by the circular movement of 51. Therefore, by driving the recording head 24 according to the image signal while moving the carriage 23, ink droplets are ejected from the lower side to the upper side of the stopped paper 10, and one line is recorded. After the sheet 10 is conveyed by a predetermined amount, the next line is recorded, and the sheet 10 for which recording has been completed is discharged to the discharge tray 7.

  When performing maintenance and recovery of the nozzles of the recording head 24, the carriage 23 is moved to a position opposite to the maintenance and recovery mechanism 9 that is the home position, and the suction cap 92a performs capping to perform suction and discharge from the nozzles. By performing a maintenance and recovery operation such as suction and empty discharge for discharging droplets that do not contribute to image formation, image formation by stable droplet discharge can be performed.

Next, an outline of the control unit of the image forming apparatus will be described with reference to a block diagram of FIG.
The control unit 500 temporarily stores a CPU 501 that controls the entire apparatus, various programs including a program that causes the CPU 501 to execute control (processing) according to the present invention, a ROM 502 that stores other fixed data, image data, and the like. RAM 503 for storing, rewritable nonvolatile memory 504 for holding data even while the power of the apparatus is shut off, image processing for performing various signal processing and rearrangement on image data, and other control of the entire apparatus An ASIC 505 for processing input / output signals for the purpose is provided.

  Also, a print control unit 508 including a data transfer unit for driving and controlling the recording head 24 and a driving signal generating unit, a head driver (driver IC) 509 for driving the recording head 24 provided on the carriage 23 side, A main scanning motor 25 that moves and scans the carriage 23, motor driving units 510 and 511 for driving a sub-scanning motor 151 that moves the conveyor belt 51 in a circular manner, an AC bias supply unit 512 that supplies an AC bias to the charging roller 54, and the like It has.

  The control unit 500 is connected to an operation panel 514 for inputting and displaying information necessary for the apparatus.

  The control unit 500 has an I / F 506 for transmitting and receiving data and signals to and from the host side, an information processing device such as a personal computer, an image reading device such as an image scanner, and an imaging device such as a digital camera. Or the like from the host 600 side via the cable or network.

  The CPU 501 of the control unit 500 reads and analyzes the print data in the reception buffer included in the I / F 506, performs necessary image processing, data rearrangement processing, and the like in the ASIC 505, and prints the image data. The data is transferred from the unit 508 to the head driver 509. Note that generation of dot pattern data for image output is performed by the printer driver 601 on the host 600 side.

  The print control unit 508 transfers the above-described image data as serial data, and outputs a transfer clock, a latch signal, a control signal, and the like necessary for transferring the image data and confirming the transfer to the head driver 509. Including a D / A converter for D / A converting D / A conversion of drive pulse pattern data stored in the ROM, a voltage signal amplifier, a current amplifier, and the like, and a drive signal or a plurality of drive pulses Is output to the head driver 509.

  The head driver 509 selectively selects a drive pulse that constitutes a drive signal provided from the print control unit 508 based on image data corresponding to one line of the print head 24 that is input serially, and drops droplets of the print head 24. The recording head 24 is driven by applying it to a driving element (for example, a piezoelectric element) that generates energy to be discharged. At this time, by selecting a drive pulse that constitutes a drive signal, for example, droplets having different droplet sizes, such as large droplets, medium droplets, and small droplets, can be ejected and dots having different sizes can be sorted.

  The I / O unit 513 acquires information from the main scanning encoder 123, the sub-scanning encoder 156, and various sensor groups 515 mounted on the apparatus, extracts information necessary for controlling the printer, and print control unit 508. Also used to control the motor drive units 510 and 511 and the AC bias supply unit 511. The sensor group 515 includes an optical sensor (paper sensor) 521 provided on the carriage 23 for detecting the position of the paper, a thermistor for monitoring the temperature and humidity in the machine, a sensor for monitoring the voltage of the charging belt, and a cover. The I / O unit 513 can process various sensor information.

  For example, the CPU 501 detects a speed detection value and a position detection value obtained by sampling a detection pulse from the encoder sensor 122 constituting the main scanning encoder 123, and a speed target value and a position target obtained from a previously stored speed / position profile. The drive output value (control value) for the main scanning motor 25 is calculated based on the value and the main scanning motor 25 is driven via the motor driving unit 210. Similarly, a speed detection value and a position detection value obtained by sampling a detection pulse from the encoder sensor 155 constituting the sub-scanning encoder 156, a speed target value and a position target value obtained from a previously stored speed / position profile, and Based on this, a drive output value (control value) for the sub-scanning motor 151 is calculated, and the sub-scanning motor 151 is driven via the motor driving unit 211.

  Further, the control unit 500 drives the maintenance / recovery mechanism 9 via the maintenance / recovery drive unit 534 to move the cap 92 forward and backward relative to the nozzle surface of the recording head 24, move the wiper member 94, and the suction pump. Drive. In addition, by driving the supply pump 13 via the pump drive unit 535, ink is sent from the main tank (not shown) to the head tank 29, or ink is sent back from the head tank 29 to the main tank.

  Next, the liquid discharge head constituting the recording head in the first embodiment of the present invention will be described with reference to FIGS. 4 is an external perspective explanatory view of the head, FIG. 5 is a schematic cross-sectional explanatory view along the plane XX of FIG. 4 (direction perpendicular to the nozzle arrangement direction: short direction), and FIG. 6 is FIG. It is typical sectional explanatory drawing which follows YY plane (nozzle arrangement direction: longitudinal direction).

  The liquid discharge head 200 includes a plurality of nozzles 201 that discharge droplets, individual liquid chambers 202 that communicate with the nozzles 201, a common liquid chamber 203 that supplies ink to the individual liquid chambers 202, and a common liquid chamber 203. And a liquid supply port portion 204 through which ink is supplied from the head tank 29, and is disposed in a state in which droplets are ejected upward in the vertical direction as described above. The “liquid chamber” includes what is referred to as a flow path, and the “individual liquid chamber” includes, for example, what are referred to as a pressurizing chamber, a pressurized liquid chamber, a pressure chamber, a pressure generating chamber, and the like.

  Although not shown, actuator means for generating a pressure for ejecting droplets to the individual liquid chamber 202 is provided, and as described above, the actuator means includes, for example, a piezoelectric actuator including a piezoelectric element, electric heat, and the like. A thermal actuator including a conversion element, an electrostatic actuator including a diaphragm and a counter electrode, or the like can be used.

  Here, the wall surface 221 of the common liquid chamber 203 facing the inlet 202a side of the individual liquid chamber 202 is an arrangement direction (nozzle arrangement direction) of the plurality of individual liquid chambers and a direction (nozzle arrangement) orthogonal to the arrangement direction of the plurality of individual liquid chambers. In the direction orthogonal to the direction), the inclined surface is formed so as to be linearly inclined in the direction of increasing in the height direction from the center portion toward both end portions.

  A bubble reservoir 222 for collecting bubbles is provided outside the region facing the inlet 202a side of the individual liquid chamber 202 on both end sides of the common liquid chamber 203 in the nozzle arrangement direction and the direction orthogonal to the nozzle arrangement direction.

  At this time, since the bubble reservoir 222 is provided on the highest position side of the wall surface 221 which is an inclined surface, the bubble reservoir 222 is positioned higher than the region where the inlet 202a of the individual liquid chamber 202 faces in the height direction. As a result, the amount of bubbles that can be accumulated in the bubble reservoir 222 can be increased.

  With this configuration, the bubbles 301 that flow into the common liquid chamber 203 together with the ink 300 or remain in the common liquid chamber 203 at the time of initial filling are guided by the wall surface 221 as indicated by arrows, and are It is stored in the bubble reservoir 222 and does not enter the individual liquid chamber 202 or the nozzle 201 on the downstream side of the common liquid chamber 203 (which means that the intrusion is reduced).

  As a result, air bubbles are mixed into the individual liquid chamber 202 and the nozzle 201, causing the discharge pressure by the actuator means to be applied unevenly, or the pressure to be reduced, and the discharge direction of the discharged liquid droplets is bent. In addition, the occurrence of ejection failure such as ejection failure is prevented, so that image formation can be performed stably with high image quality.

  On the other hand, as in the comparative example shown in FIG. 12, when the wall surface 221 facing the inlet 202a side of the individual liquid chamber 202 of the common liquid chamber 203 is a flat surface, the bubbles 301 move to the wall surface 221 side by buoyancy, Since the liquid stays while closing the inlet 202a of the chamber 202, a discharge failure such as a change in the discharge direction of the discharged liquid droplets or inability to discharge occurs.

  In this way, the wall surface facing the inlet side of the individual liquid chambers of the common liquid chamber is higher in the height direction from the central portion toward both end sides in the direction in which the plurality of individual liquid chambers are arranged and in the direction orthogonal to the arrangement direction. By forming a bubble reservoir for collecting bubbles outside the region facing the inlet side of the individual liquid chambers, both ends of the common liquid chamber are formed in a linearly inclined manner in the direction of the liquid. Air bubbles in the recording head that discharges droplets upward in the vertical direction are prevented from entering the downstream flow path from the common liquid chamber, so that stable image formation can be performed.

  Next, a liquid discharge head constituting the recording head in the second embodiment of the present invention will be described with reference to FIGS. 7 is a schematic cross-sectional explanatory view along a direction orthogonal to the nozzle arrangement direction of the head, and FIG. 6 is a schematic cross-sectional explanatory view along the nozzle arrangement direction.

  In the present embodiment, the wall surface 221 of the common liquid chamber 203 facing the inlet 202a side of the individual liquid chamber 202 is an arrangement direction (nozzle arrangement direction) of the plurality of individual liquid chambers and a direction orthogonal to the arrangement direction of the plurality of individual liquid chambers ( In the direction orthogonal to the nozzle arrangement direction), the inclined surface is formed so as to incline in a curved shape in the direction of increasing in the height direction from the center portion toward both end portions.

  Even with this configuration, the bubbles 301 can be guided to the bubble reservoir 222 as in the first embodiment, and the bubbles 301 can be prevented from entering the downstream flow path from the common liquid chamber 203.

  In the first and second embodiments, since the wall surface 221 facing the inlet 202a of the individual liquid chamber 202 of the common liquid chamber 203 is an inclined surface, the flow path length of each individual liquid chamber 202 is individually individual. This is different between the liquid chambers 202. Therefore, when the actuator means (pressure generating means) corresponding to each individual liquid chamber 202 is driven with the same drive waveform, the droplet discharge characteristics of each nozzle 201 are different.

  Therefore, when the liquid discharge heads of these embodiments are provided, the individual liquid chambers 202 (as the drive waveform data stored in the nonvolatile storage means such as the ROM 502 or other ROM of the control unit 500 described above are used. Drive waveform data corresponding to each nozzle 201) is stored and held.

  Thereby, even when the liquid discharge heads of these embodiments are provided, the droplet discharge characteristics of each nozzle 201 can be made uniform.

  Next, a liquid discharge head constituting a recording head according to a third embodiment of the present invention will be described with reference to FIGS. 9 is a schematic cross-sectional explanatory view along a direction orthogonal to the nozzle arrangement direction of the head, and FIG. 10 is a schematic cross-sectional explanatory view along the nozzle arrangement direction.

  In the present embodiment, the wall surface 221 of the common liquid chamber 203 facing the inlet 202a side of the individual liquid chamber 202 is an arrangement direction (nozzle arrangement direction) of the plurality of individual liquid chambers and a direction orthogonal to the arrangement direction of the plurality of individual liquid chambers ( In the direction orthogonal to the nozzle arrangement direction), the inclined surface is formed so as to be inclined in a curved shape in a direction increasing in the height direction from the one end side toward the other end side.

  Even with this configuration, the bubbles 301 can be guided to the bubble reservoir 222 as in the first embodiment, and the bubbles 301 can be prevented from entering the downstream flow path from the common liquid chamber 203.

  Next, a liquid discharge head constituting the recording head in the fourth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a schematic cross-sectional explanatory view along the nozzle arrangement direction of the head.

  In the present embodiment, the wall surface 221 of the common liquid chamber 203 facing the inlet 202a side of the individual liquid chamber 202 is a flat surface, and the common liquid chamber 203 is centered in the arrangement direction (nozzle arrangement direction) of the plurality of individual liquid chambers. A guide member 224 having an inclined surface 225 formed so as to be linearly inclined in a direction increasing in the height direction from the portion toward both ends is disposed.

  Further, on both end sides of the common liquid chamber 203 in the nozzle arrangement direction, bubble reservoirs 222 for collecting bubbles outside the region facing the inlet 202a side of the individual liquid chamber 202 are provided at a position higher than the wall surface 221.

  With this configuration, since the bubbles 301 that have entered the common liquid chamber 202 are guided to the bubble reservoir 222 by the inclined surface 225 of the guide member 224, the downstream side of the common liquid chamber 203 is the same as in the above embodiments. It is possible to prevent the bubbles 301 from entering the channel.

  Further, by providing the guide member 224, the flow path becomes narrow and the flow velocity can be increased, and the bubble discharge property during head cleaning can be improved. Furthermore, since the channel lengths of the individual liquid chambers 202 can be made uniform, it is not necessary to have drive waveform data corresponding to the individual liquid chambers.

  In the present application, the “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, etc., and means a material to which ink droplets or other liquids can be attached. , Recording media, recording paper, recording paper, and the like. In addition, image formation, recording, printing, printing, and printing are all synonymous.

  The “image forming apparatus” means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “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 causing a droplet to land on the medium). ) Also means.

  The “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically, for example, includes DNA samples, resists, pattern materials, resins, and the like.

  In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

  Further, the image forming apparatus includes both a serial type image forming apparatus and a line type image forming apparatus, unless otherwise limited.

DESCRIPTION OF SYMBOLS 2 Image formation part 4 Paper supply part 5 Conveyance mechanism part 7 Maintenance recovery mechanism 23 Carriage 24 Recording head 51 Conveyance belt 200 Liquid discharge head 201 Nozzle 202 Individual liquid chamber 203 Common liquid chamber 221 Wall surface of common liquid chamber 222 Bubble accumulation

Claims (3)

A liquid discharge head disposed in a state in which droplets are discharged vertically upward;
A plurality of nozzles for discharging droplets;
A plurality of individual liquid chambers in which the plurality of nozzles communicate with each other;
A common liquid chamber for supplying liquid to the plurality of individual liquid chambers,
In the common liquid chamber, at least one of the arrangement direction of the plurality of individual liquid chambers and the direction orthogonal to the arrangement direction, from one end side to the other end side, or from the central part to both end parts side A member having an inclined surface that is inclined linearly or curvedly in a direction increasing in the height direction is disposed,
At least one end side or both end sides of the common liquid chamber in the direction in which the plurality of individual liquid chambers are arranged and in the direction orthogonal to the arrangement direction are air bubbles outside the region where the inlet side of the individual liquid chamber faces. A liquid discharge head characterized in that a bubble reservoir for accumulating water is provided. 2. The liquid ejection head according to claim 1, wherein the bubble reservoir is located higher in a height direction than a region of the common liquid chamber facing an inlet side of the individual liquid chamber. An image forming apparatus characterized by comprising a liquid discharge head according to claim 1 or 2.

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