JP2014054796A - Liquid discharge head and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge head which unfailingly absorbs vibrations transmitted to a common liquid chamber while sufficiently securing a contact area between a damper member and a liquid.SOLUTION: A liquid discharge head includes: multiple nozzles 2 which discharge droplets; multiple pressure chambers 3 which respectively communicate with the multiple nozzles 2; and a common liquid chamber 20 which supplies a liquid to the multiple pressure chambers 3. The liquid discharge head includes a damper member 13 having a hollow cylindrical body in the common liquid chamber 20. The damper member 13 is disposed so that an outer surface thereof may contact with the liquid in the common liquid chamber 20.

Description

  The present invention relates to a liquid discharge head and an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile, a copying apparatus, a plotter, and a complex machine of these, for example, a liquid discharge recording type image forming apparatus (for example, an ink jet recording apparatus) using a liquid discharge head for discharging ink droplets is known. It has been. This image forming apparatus forms an image by ejecting ink droplets from a liquid ejection head onto a recording medium.

  The liquid discharge head distributes the ink supplied from the ink tank to the plurality of pressure chambers from the common liquid chamber, and changes the volume of each pressure chamber to discharge the ink from the communicating nozzle. For example, a diaphragm is provided on a part of the wall of the pressure chamber, and the volume of the pressure chamber is changed by displacing the diaphragm by pressure conversion means such as an actuator, and the pressure is increased and ink in the pressure chamber is ejected from the nozzle. There are widely known methods, such as a method in which a heating element that generates heat when energized is provided in a pressure chamber, the pressure is increased by bubbles generated by the heat generated by the heating element, and ink in the pressure chamber is ejected from nozzles.

The pressure generated to increase the pressure in the pressure chamber is also ejected from the nozzles, and at the same time, is propagated to the common liquid chamber communicating with each pressure chamber. If this pressure is transmitted again to the pressure chamber side, it may cause the pressure in the pressure chamber to fluctuate to an unexpected value, which may cause injection failure. In addition, if the pressure fluctuation that has propagated to the common liquid chamber propagates to the adjacent pressure chambers, causing mutual interference that affects the liquid, it may cause unintended droplet leakage from the nozzle, ejection, and instability of the ejection state. Will do.
When pressure fluctuations are induced in other pressure chambers due to this fluidic crosstalk, the ink ejection characteristics such as ink ejection speed and droplet volume in the pressure chambers in which the pressure fluctuations are induced will change. Will fall.

  In order to solve the above-mentioned problem, a liquid discharge unit that suppresses fluid crosstalk by providing a damper made of a thin plate on the upper surface or lower surface of the common liquid chamber to absorb vibration propagating from the pressure chamber to the common liquid chamber. A head has been proposed (see, for example, Patent Documents 1 and 2).

  In Patent Document 1, a plurality of damper walls that flex to absorb pressure changes in the common liquid chamber are formed on the walls that define the common liquid chamber, and the elasticity of at least some of the plurality of damper walls is made different. An ink jet recording head is described. Patent Document 2 describes an ink jet head that includes a damper chamber that partitions a common liquid chamber and includes a communication path that communicates the partitioned space.

  In the liquid ejection heads described in Patent Documents 1 and 2, the pressure wave generated in the pressure chamber when ink is ejected from the nozzle by providing a damper member so as to partition the interior of the common liquid chamber into two upper and lower spaces. Can be prevented from propagating through the ink to the common liquid chamber.

However, when an individual ink flow path and a common liquid chamber are provided side by side, a damper member is provided so as to partition the inside of the common liquid chamber up and down, and when there are two contact surfaces between the ink and the damper member, The width may not be sufficient and the pressure wave may not be absorbed effectively.
In order to improve the pressure wave absorption performance of the damper member, it is important to provide the damper member so that the contact surface between the damper member and the ink is longer and the contact area is larger.

  Therefore, in view of the above problems, the present invention provides a liquid discharge head that can sufficiently secure a contact area between a damper member and a liquid and can reliably absorb vibrations propagated into a common liquid chamber. With the goal.

  In order to solve the above problems, a liquid discharge head according to the present invention supplies a plurality of nozzles that discharge droplets, a plurality of pressure chambers that respectively communicate with the plurality of nozzles, and a liquid to the plurality of pressure chambers. In the liquid discharge head including a common liquid chamber, a hollow cylindrical damper member is provided in the common liquid chamber, and the damper member is disposed at a position where an outer surface can contact the liquid in the common liquid chamber. A liquid discharge head.

  According to the liquid discharge head of the present invention, it is possible to provide a liquid discharge head that can sufficiently secure a contact area between the damper member and the liquid and can reliably absorb the vibration propagated into the common liquid chamber. Can do.

3 is an external perspective view illustrating an example of a liquid discharge head. FIG. FIG. 2 is an example of a perspective view of a nozzle substrate and a liquid chamber substrate in the liquid ejection head of FIG. 1 viewed from the nozzle side. It is an external appearance perspective view which shows an example of a common liquid chamber board | substrate. FIG. 5 is a perspective view showing an example of a liquid discharge head separately for each substrate. FIG. 2 is a schematic diagram illustrating an example of a B1-B2 cross section of the liquid ejection head in FIG. 1. FIG. 2 is a schematic diagram illustrating an example of a C1-C2 cross section of the liquid ejection head in FIG. 1. 1 is a schematic configuration diagram illustrating an overall configuration of a mechanism unit as an example of an image forming apparatus. It is explanatory drawing of the principal part plane of an example of an image forming apparatus. It is a schematic diagram which shows an example of the B1-B2 cross section in the conventional liquid discharge head. It is a schematic diagram which shows an example of the C1-C2 cross section in the conventional liquid discharge head.

  Hereinafter, a liquid discharge head and an image forming apparatus according to the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the embodiments of the examples shown below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art. Any aspect is included in the scope of the present invention as long as the operations and effects of the present invention are exhibited.

FIG. 1 shows an external perspective view of one embodiment of the liquid discharge head.
As shown in FIG. 1, the liquid discharge head includes a nozzle substrate 1, a liquid chamber substrate 12, a common liquid chamber substrate 8, and an ink supply port substrate 9 that are stacked in this order from below, and an FPC (flexible printed circuit board) on the liquid chamber substrate 12. 17 is joined.

  FIG. 2 is a perspective view of the nozzle substrate and the liquid chamber substrate in the liquid discharge head of FIG. 1 as viewed from the nozzle side. Further, FIG. 9 shows a B1-B2 cross section shown in FIG. 2 and FIG. 10 shows a C1-C2 cross section of the conventional liquid discharge head. Hereinafter, with reference to these FIG. 1, FIG. 2, FIG. 9, and FIG. 10, an aspect of a liquid discharge head that discharges ink droplets as a liquid will be described.

In the nozzle substrate 1, a large number of nozzle holes 2 having a diameter of 10 to 30 μm are formed corresponding to the pressure chambers 3. The nozzle substrate 1 is formed of a metal such as stainless steel or nickel, a resin such as a polyimide resin film, silicon, or a combination thereof.
Further, a water repellent film such as a plating film or a water repellent coating is formed on the surface in the ejection direction of the nozzle substrate 1 in order to ensure water repellency with the liquid to be ejected (ink in this embodiment). ing.

  In the liquid chamber substrate 12, the liquid supply substrate 7 and the protective frame substrate 19 are formed of silicon, and a drive circuit member (drive IC) 11, an electromechanical conversion element (piezoelectric element) 15, electrodes (not shown), and wiring It is composed of the member 10.

A plurality of pressure chambers 3 are formed in the liquid supply substrate 7.
The pressure chamber 3 communicates with the nozzle hole 2 and its upper wall is formed by a diaphragm 14. A fluid resistance 4 is disposed on one side of the pressure chamber 3 and communicates with the ink introduction path 5 and the ink supply groove 6.

A drive circuit member (drive IC) 11 is installed at the center of the diaphragm 14, and electromechanical conversion elements (piezoelectric elements) 15 are installed on both sides thereof.
Electrodes (not shown) are formed above and below the electromechanical transducer (piezoelectric element) 15, and a wiring member 10 is flip-chip bonded on the electrode pattern (not shown).

The protective frame substrate 19 is disposed on the upper surface of the liquid chamber substrate 12.
A recess is formed in the protective frame substrate 19 at a position corresponding to the diaphragm 14. The recess is disposed so as to surround the electromechanical transducer (piezoelectric element) 15.

The common liquid chamber substrate 8 constitutes a common liquid chamber 20 corresponding to each nozzle row.
The common liquid chamber forming substrate 8 is disposed on the upper surface of the liquid chamber substrate 12, and a liquid supply substrate (ink supply port substrate) 9 is disposed on the upper surface of the common liquid chamber substrate 8.
The common liquid chamber substrate 8 and the ink supply port substrate 9 are joined by an adhesive, and the liquid chamber substrate 12, the common liquid chamber substrate 8, and the ink supply port substrate 9 are configured to communicate with each other.

  The ink supply property can be improved by making the shape of the ink supply port substrate 9 on the common liquid chamber 20 side a curved shape. The main body of the droplet discharge head sends ink from an ink tank (not shown) to the common liquid chamber 20 formed by the common liquid chamber substrate 8 and supplies the ink to the liquid chamber substrate 12.

By reducing the voltage applied to the electromechanical transducer (piezoelectric element) 15 from the reference potential, the electromechanical transducer (piezoelectric element) 15 contracts, the diaphragm 14 descends, and the volume of the pressure chamber 3 expands. Ink flows into the pressure chamber 3.
Thereafter, the voltage applied to the electromechanical conversion element (piezoelectric element) 15 is increased to extend the electromechanical conversion element (piezoelectric element) 15 in the stacking direction, and the diaphragm 14 is deformed in the direction of the nozzle hole 2 so that the volume of the pressure chamber 3 is increased. By contracting the ink, the ink in the pressure chamber 3 is pressurized and ink droplets are ejected (ejected) from the nozzle hole 2.

By returning the voltage applied to the electromechanical transducer (piezoelectric element) 15 to the reference potential, the diaphragm 14 is restored to the initial position, and the pressure chamber 3 expands to generate a negative pressure. The pressure chamber 3 is filled with ink from 20.
After the vibration of the meniscus surface of the nozzle 2 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Here, when ink is ejected, the pressure wave acting on the pressure chamber 3 generates not only the forward component toward the nozzle hole 2 but also the backward component toward the common liquid chamber substrate 8 side. The vibration generated in the pressure chamber 3 due to the pressure wave of the backward component propagates to the other pressure chamber 3 via the ink in the common liquid chamber 20, and pressure fluctuation is induced in the pressure chamber 3, so-called fluid crossing. Talk may occur and stable ejection may be difficult.

Therefore, it is necessary to provide, for example, a damper member shown in FIG. 3 as a mechanism for absorbing and relaxing the backward component of the pressure wave.
FIG. 4 shows a perspective view of the liquid discharge head according to the present embodiment including the damper member, which is separated for each substrate. FIG. 5 shows a B1-B2 cross section shown in FIG. 2, and FIG. 6 shows a C1-C2 cross section. In addition, about structures other than a damper member, it is the same as that of what was demonstrated in FIG.9 and FIG.10.

  As shown in FIGS. 4 to 6, the liquid ejection head according to this embodiment includes a nozzle substrate 1 in which a plurality of nozzle holes 2 are formed and a plurality of pressures individually separated by side walls corresponding to the nozzle holes 2. The liquid chamber substrate 12 having the chamber 3 and the electromechanical conversion element 15 that vibrates the vibration plate 14 constituting a part of the pressure chamber 3 and the liquid chamber substrate 12 are integrally formed, and the liquid is supplied to the pressure chamber 3. A common liquid chamber substrate 8 that forms the common liquid chamber 20, a liquid supply substrate 9 in which a supply path for supplying liquid to the common liquid chamber 20 is formed, and a drive circuit member 11 that drives the electromechanical conversion element 15 are provided. Then, the liquid is discharged from the nozzle hole 2 by the pressure generated in the pressure chamber 3 by the vibration of the vibration plate 14.

3 and 4, a hollow cylindrical damper member 13 formed of an elastic body is provided in the common liquid chamber 20, and the outer surface of the damper member 13 is liquid in the common liquid chamber 20. It is arranged in a position where it can contact.
Here, the “position where the liquid in the common liquid chamber can come into contact” means a position included in the range of the water level (the height of the liquid surface) assumed in the common liquid chamber, and at least the lowermost surface of the damper member 13 is It is required to be in this position.
In addition, as the cylindrical body, an example of a cylindrical body is shown in FIGS. 3 and 4, but a cylindrical body having a polygonal cross section (for example, a quadrangular column, a hexagonal column, or the like) may be used.

In the liquid ejection head according to the present embodiment, as shown in FIGS. 3 and 4, the damper member 13 is provided so that the direction intersecting the nozzle arrangement direction and the longitudinal direction of the cylindrical body are substantially parallel.
Further, as shown in FIG. 6, a plurality of damper members 13 are arranged along the nozzle arrangement direction.

  In the embodiment shown in FIG. 6, the arrangement intervals of the plurality of damper members 13 are substantially the same interval, but the present invention is not limited to this. For example, the arrangement interval of the damper members 13 may be wider in the vicinity of both ends in the longitudinal direction of the common liquid chamber 20 than in the vicinity of the central portion of the common liquid chamber 20. Thereby, the fall of the flow rate by arrangement | positioning of the damper member 13 can be reduced in the vicinity of the both ends of the common liquid chamber 20 where a flow rate becomes slow.

  The damper member 13 has an internal space 16 communicating with the atmosphere through an open end. Thus, the air inside the cylindrical body does not become a resistance against the deformation of the damper member 13, the damper member 13 can be sufficiently deformed, and the efficiency is improved even if a large pressure fluctuation occurs during ink ejection. Vibration can be absorbed.

As shown in FIG. 3, the damper member 13 is formed to penetrate the common liquid chamber substrate 8 in the short direction. By setting the penetrating direction in the short direction, the damper member 13 is easily deformed with respect to the vibration propagated to the common liquid chamber that is generated when ink is ejected, and the vibration can be reliably absorbed.
Further, when the damper member 13 is formed by injection molding, it is advantageous because the thickness of the damper member 13 can be reduced.

Moreover, it is preferable that the outer surface of the damper member 13 has unevenness.
The shape of the unevenness is not particularly limited as long as it does not hinder the flow of ink in the common liquid chamber 20, and examples thereof include a gently continuous sine curve shape.
Due to the unevenness on the surface, the area in contact with the ink in the common liquid chamber 20 is increased, and the vibration propagated to the common liquid chamber generated during ink ejection can be reliably absorbed.

The damper member 13 is preferably made of a resin having elasticity, and specifically, is preferably made of a thermoplastic elastomer resin. By forming a hollow cylindrical member with a thermoplastic elastomer resin, vibrations can be reliably absorbed.
The common liquid chamber substrate 8 is preferably made of a thermoplastic resin. By forming the same thermoplastic resin as the damper member 13, the damper member 13 and the common liquid chamber substrate 8 can be integrally formed.

  The common liquid chamber substrate 8 and the damper member 13 are integrally formed by either insert molding or two-color molding.

A method of forming parts by the insert molding method in order to integrally form the common liquid chamber substrate 8 and the damper member 13 by the injection molding method will be described.
First, the damper member 13 is formed. A mold for forming the damper member 13 is formed of a cylindrical cavity and a core. First, resin is filled between the cylindrical mold cavity and the core, and the cylindrical damper member 13 is formed by injection molding. A thermoplastic elastomer resin is suitable as the resin for forming the damper member 13 as described above.
The thickness of the damper member 13 is desirably 0.1 mm or less, and the longitudinal elastic modulus is desirably 5 MPa or less.

  The mold for forming the common liquid chamber substrate 8 is formed of a core for forming the cavity and the common liquid chamber 20. The core forming the common liquid chamber 20 is formed with a notch for fixing the damper member 13 formed by the injection molding.

The common liquid chamber substrate 8 is formed of a thermoplastic resin as described above. The common liquid chamber substrate 8 is bonded to the liquid chamber substrate 12 formed of silicon by an adhesive, but heating may be required to cure the adhesive, and thus heat for forming the common liquid chamber substrate 8 is used. By selecting polyphenylene sulfide (PPS) having a linear expansion coefficient close to that of silicon as the plastic resin, it is possible to reduce the warpage and misalignment of parts due to heating.
In addition, polyphenylene sulfide (PPS) is excellent in ink resistance and is suitable for forming the common liquid chamber 20 of the liquid discharge head.

  The damper member 13 formed by injection molding is fixed to the notch portion of the core for forming the common liquid chamber 20 of the common liquid chamber substrate 8, and resin is put into the mold cavity for forming the common liquid chamber substrate 8. By filling and forming the common liquid chamber substrate 8, the common liquid chamber substrate 8 and the damper member 13 can be integrally formed.

Further, in order to integrally form the common liquid chamber substrate 8 and the damper member 13 by the injection molding method, it is also possible to perform component formation by the two-color molding method.
For example, first, the damper member 13 is formed by filling a resin between a cylindrical mold cavity and a core, and the damper member 13 is placed in the mold cavity of the common liquid chamber substrate 8 with the damper member 13 remaining in the same core. The common liquid chamber substrate 8 can be integrally formed by filling the mold cavity with resin.

  By forming the common liquid chamber substrate 8 and the damper member 13 integrally, there is no need for bonding, so the number of work steps can be reduced, and since there is no bonding, damage to the damper member 13 of the thin film is reduced during the operation. Can do. Further, since no interface due to bonding occurs, ink does not flow out from the interface.

Hereinafter, the process (manufacturing method) which comprises a liquid discharge head is demonstrated.
First, a method for bonding the liquid chamber substrate 12 and the nozzle substrate 1 will be described.
First, an adhesive is printed on the liquid supply substrate 7 side of the liquid chamber substrate 12 by thin film printing. As the adhesive, for example, a thermosetting adhesive or a room temperature curable adhesive is used.

  Next, the liquid chamber substrate 12 to which the adhesive is applied and the nozzle substrate 1 to which the adhesive is not applied are set in the bonding apparatus. Since the nozzle substrate 1 and the liquid chamber substrate 12 are aligned with the nozzle hole 2 and the pressure chamber 3 corresponding to the nozzle hole 2, the higher the density of the nozzle holes 2, the higher the bonding position accuracy is required. In order to achieve this requirement, alignment marks are provided on each component, and both alignment marks are detected and adjusted by an image processing apparatus provided in the joining apparatus.

After the position adjustment between the components is completed, the nozzle substrate 1 and the liquid chamber substrate 12 are temporarily fixed. Examples of the temporary fixing method include a method of curing using an ultraviolet curable resin.
After the nozzle substrate 1 and the liquid chamber substrate 12 are temporarily fixed, in order to seal the nozzle substrate 1 and the liquid chamber substrate 12 with certainty, the pressure substrate is pressurized and heated to cure the adhesive.

Next, the component in which the nozzle substrate 1 and the liquid chamber substrate 12 are bonded and the component in which the damper member 13 is integrally formed in the common liquid chamber 20 of the common liquid chamber substrate 8 are bonded with an adhesive.
The adhesive is applied to the common liquid chamber substrate 8 side by thin film printing or a dispenser. As the adhesive, a thermosetting adhesive or a room temperature curable adhesive is used.

  As a component position adjusting method, a damper member 13 is integrally formed in a common liquid chamber of the common liquid chamber substrate 8 and a component in which the nozzle substrate 1 and the liquid chamber substrate 12 are joined to a jig having a pressurizing mechanism. The parts are stacked, and each part is abutted against the positioning adjustment pin to ensure the joining position accuracy. After positioning the parts, the adhesive is cured by applying pressure and heating in order to securely seal the parts.

Since the common liquid chamber substrate 8 is formed of a thermoplastic resin, the bonding strength with the resin component can be secured by forming a SiO ₂ film at the interface between the adhesive and the resin component by sputtering or vapor deposition.

Next, the ink supply port substrate 9 and the component obtained by bonding the component formed integrally with the damper member 13 to the common liquid chamber 20 of the nozzle substrate 1, the liquid chamber substrate 12, and the common liquid chamber substrate 8 are bonded with an adhesive. To do. As the adhesive, a thermosetting adhesive or a room temperature curable adhesive is used.
As a joining method, a nozzle substrate 1, a liquid chamber substrate 12, a component in which a damper member 13 is integrally formed in a common liquid chamber 20 of a common liquid chamber substrate 8, and an ink supply port using a jig equipped with a pressurizing mechanism The components 9 are stacked in this order, and each component is abutted against the positioning adjustment pin to ensure the joining position accuracy. After positioning the parts, the adhesive is cured by applying pressure and heating in order to securely seal the parts.

Next, the FPC 17 is bonded to the liquid chamber substrate 12 to which the electromechanical conversion element (piezoelectric element) 15, the electrode (not shown), and the drive circuit member (drive IC) 11 are bonded. Examples of the bonding method include wire bonding and laser bonding.
The liquid discharge head is completed through the above steps.

When the damper member 13 is formed by injection molding, the contact area between the damper member 13 and the ink can be increased by making the surface shape of the damper member 13 uneven.
Since the damper member 13 is formed of an elastic resin, even if the mold core has irregularities, the core can be forcibly removed and the irregularities can be easily formed. Similarly, when the cross-sectional shape of the damper member 13 is a shape other than a circle (for example, a polygon), it can be easily formed.

  The common liquid chambers 20 formed in the common liquid chamber substrate 8 are not limited to two rows, and may be formed in three or more rows.

Next, an example of an image forming apparatus including the liquid discharge head will be described with reference to FIGS.
FIG. 7 is a schematic configuration diagram illustrating the entire configuration of the mechanism unit of the image forming apparatus, and FIG. 8 is a plan view illustrating a main part of the mechanism unit. The image forming apparatus according to the present embodiment is a serial type image forming apparatus, and is a guide component horizontally mounted on the left and right side plates 201A and 201B.

The carriage 233 is slidably held in the main scanning direction by the main and slave guide rods 231 and 232, and is moved and scanned in the direction indicated by an arrow (carriage main scanning direction) via a timing belt by a main scanning motor (not shown).
The carriage 233 is provided with liquid discharge heads 234a and 234b comprising the liquid discharge head according to the present invention for discharging ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). (When not distinguished, it is referred to as “liquid ejection head 234”.) Nozzle rows comprising a plurality of nozzles are arranged in the sub-scanning direction orthogonal to the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

Each of the liquid discharge heads 234 has two nozzle rows, and one nozzle row of the liquid discharge head 234a discharges black (K) droplets and the other nozzle row discharges cyan (C) droplets. One nozzle row of the head 234b discharges magenta (M) droplets, and the other nozzle row discharges yellow (Y) droplets.
The carriage 233 is equipped with head tanks 235a and 235b (referred to as “head tank 235” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the liquid ejection head 234. The sub tank 235 is supplementarily supplied with ink of each color from the ink cartridge 210 of each color via the supply tube 36 of each color.

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

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the liquid discharge head 234, a guide component 245 for guiding the sheet 242, a counter roller 246, a conveyance guide component 247, and a tip pressurization. A pressing member 248 having a roller 249 is provided, and a conveying belt 251 is provided as a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the liquid ejection head 234.

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

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

A duplex unit 271 is detachably mounted on the back surface of the apparatus body 1. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.
Further, a maintenance / recovery mechanism that is a head maintenance / recovery device according to the present invention includes a recovery means for maintaining and recovering the state of the nozzles of the liquid ejection head 234 in the non-printing region on one side in the scanning direction of the carriage 233. 281 is arranged.

  The maintenance and recovery mechanism 281 includes cap parts (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the liquid ejection head 234, and nozzles. A wiper blade 283 which is a blade part for wiping the surface, and an idle discharge receptacle 284 for receiving droplets when performing idle discharge for discharging droplets that do not contribute to recording in order to discharge the thickened recording liquid. I have.

  In addition, in the non-printing area on the other side in the scanning direction of the carriage 233, the liquid that receives liquid droplets when performing idle ejection that ejects liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An ink recovery unit (empty discharge receiver) 288 that is a recovery container is disposed, and the ink recovery unit 288 includes an opening 289 along the nozzle row direction of the liquid discharge head 234 and the like.

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

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

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

  Since this image forming apparatus is equipped with the above-described liquid discharge head, the ink droplet discharge characteristics are stable and a high-quality image can be formed.

  In the above embodiment, the image forming apparatus as an ink jet recording apparatus is described. However, the present invention is not limited to this. For example, the image forming apparatus is not limited to a copying machine, and may be a printer, a facsimile, or a plurality of apparatuses. It may be a multifunction machine having a function. Further, the present invention can be similarly applied to a line type liquid discharge head and a line type image forming apparatus. Furthermore, the present invention can be applied to a liquid discharge head or an image forming apparatus that discharges a DNA sample, a resist, a pattern material, or the like. Further, the liquid discharge head is not limited to the piezoelectric head, and can be similarly applied to other liquid discharge heads such as a thermal head and an electrostatic head.

DESCRIPTION OF SYMBOLS 1 Nozzle board 2 Nozzle hole 3 Pressure chamber 4 Fluid resistance part 5 Ink introduction path 6 Ink supply groove 7 Liquid supply board 8 Common liquid chamber board 9 Liquid supply board (ink supply port board)
10 Wiring member 11 Drive circuit member (drive IC)
12 Liquid chamber substrate 13 Damper member 14 Vibration plate 15 Electromechanical conversion element (piezoelectric element)
16 Internal space of damper member 17 FPC (flexible printed circuit board)
18 Side wall 19 Protective frame substrate 20 Common liquid chamber 234 Liquid discharge head

Japanese Patent No. 4453965 Japanese Patent No. 4320596

Claims (8)

A plurality of nozzles for discharging droplets;
A plurality of pressure chambers respectively leading to the plurality of nozzles;
In a liquid discharge head comprising a common liquid chamber that supplies liquid to the plurality of pressure chambers,
A liquid discharge head, comprising: a hollow cylindrical damper member in the common liquid chamber, wherein the damper member is disposed at a position where an outer surface can come into contact with the liquid in the common liquid chamber.   The liquid ejection head according to claim 1, wherein the inside of the damper member communicates with the atmosphere through an opening end.   The liquid discharge head according to claim 1, wherein an outer surface of the damper member has irregularities.   The liquid ejection head according to claim 1, wherein the damper member is made of a thermoplastic elastomer resin.   5. The liquid discharge head according to claim 1, wherein the common liquid chamber substrate forming the common liquid chamber is made of a thermoplastic resin.   The common liquid chamber substrate that forms the common liquid chamber and the damper member are integrally formed by either insert molding or two-color molding. Liquid discharge head.   The liquid ejection head according to claim 1, wherein the damper member is formed so as to penetrate in a short direction of a common liquid chamber substrate forming the common liquid chamber.   An image forming apparatus comprising the liquid discharge head according to claim 1.