JP5533476B2 - Liquid ejection head and image forming apparatus - Google Patents

Description

  The present invention particularly relates to a liquid discharge head and an image forming apparatus including a nozzle plate that has been pressed.

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

  In the present application, the “image forming apparatus” of the liquid discharge recording method is an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or the like. In addition, “image formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply It also means that a droplet is landed on a medium). “Ink” is not limited to ink, but is used as a general term for all liquids capable of image formation, such as recording liquid, fixing processing liquid, and liquid. DNA samples, resists, pattern materials, resins and the like are also included. In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

  As the liquid ejection head, a piezoelectric head using a piezoelectric element as pressure generating means for pressurizing ink, which is a liquid in a liquid chamber that communicates with a nozzle that ejects droplets, and generating a pressure, thermal using a heating resistor A type head, an electrostatic type head using a diaphragm and an electrode are known.

  In such an image forming apparatus, in order to cope with high image quality, droplets are reduced and nozzle density is increased, and in order to cope with high speed, the drive frequency is increased and the number of nozzles per head is increased. Increasing the length of heads typified by line-type heads is increasing.

  By the way, as a nozzle plate (nozzle forming member, nozzle plate) for forming nozzles (nozzle holes) for discharging liquid droplets constituting the liquid discharge head, a nozzle plate is formed by pressing a metal plate such as SUS. It has been.

  For example, the depression having a region farther from the first surface than the second surface of the metal plate facing the first surface by pressing the first surface of the metal plate with a punch provided in the mold. Forming a raised portion that is raised from the second surface so as to surround the vicinity of the tip of the metal plate, and a nozzle hole having an opening at a position farther from the first surface than the second surface is formed As described above, a manufacturing method is known in which a machining process is performed in which a part of the raised portion is removed by machining the raised portion in parallel with the second surface (Patent Document 1).

  Regarding the surface treatment of the nozzle plate, conventionally, an oxide film is formed on the liquid ejection surface of the nozzle plate and the surface opposite to the liquid ejection surface (side surface of the liquid chamber), and the nozzle substrate and water repellency are formed. Improve the adhesion between the film, the adhesion between the nozzle substrate and the flow path member forming the liquid chamber (Patent Document 2), the film thickness of the oxide film formed on the liquid ejection surface and the liquid chamber side surface of the nozzle plate (Patent Document 3) is known.

JP 2006-224619 A JP 2006-042426 A JP 2009-012202 A

  However, when the nozzle is formed by press working as described above, the nozzle base material (member forming the nozzle hole) is plastically deformed, and the flatness of the nozzle plate is lowered. When the nozzle plate is deformed and the flatness is lowered, the nozzle plate is bonded to a flow channel member that forms a liquid chamber (individual flow channel) or the like that communicates with the nozzle. The adhesive protrudes into the liquid chamber due to the application of a large amount of (leads to variations in droplet discharge characteristics, etc.).

  What forms the oxide film on both surfaces of the nozzle base material disclosed in Patent Document 2 described above is made for the purpose of improving the adhesion to the water repellent film and the flow path member, and is generated in the nozzle base material. However, the plastic deformation cannot be reduced simply by forming on both sides.

  In addition, those in which oxide films having different film thicknesses are formed on both surfaces of the nozzle base material disclosed in Patent Document 3 are not subjected to plastic deformation due to press working on the nozzle base material. On the contrary, the warp of the nozzle base material becomes large.

  The present invention has been made in view of the above problems, and has an object to reduce the variation in the flatness of the nozzle plate formed by press working to improve the bonding quality and bonding reliability, and to improve the droplet discharge characteristics. And

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A nozzle plate having a plurality of nozzle rows in which a plurality of nozzles formed by pressing is arranged, and a liquid chamber in which the nozzles communicate with each other are formed, and are joined to a surface opposite to the liquid discharge surface of the nozzle plate. In a liquid discharge head having a flow path member,
The nozzle plate is formed of a metal plate,
Films having compressive stress on the metal plate are formed on both surfaces of the metal plate,
The thickness of the film was configured such that the surface side joined to the flow path member was thicker than the liquid ejection surface side.

Here, the film may be a film made of SiO ₂ .

The liquid discharge head according to the present invention includes:
A nozzle plate having a plurality of nozzle rows in which a plurality of nozzles formed by pressing is arranged, and a liquid chamber in which the nozzles communicate with each other are formed, and are joined to a surface opposite to the liquid discharge surface of the nozzle plate. In a liquid discharge head having a flow path member,
The nozzle plate is formed of a metal plate,
Films having a tensile stress on the metal plate are formed on both surfaces of the metal plate,
The thickness of the film is configured such that the liquid discharge surface side is formed thicker than the surface side joined to the flow path member.

  In these liquid discharge heads according to the present invention, the film may be formed only in the portion between the nozzle rows.

A method for manufacturing a liquid discharge head according to the present invention includes:
Forming a recess to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the metal plate is formed, and opening the nozzle;
Forming a film having a compressive stress on the polished surface side of the metal plate;
Forming the film having the compressive stress on the polishing surface side on the surface side where the concave portion of the metal plate is formed, and forming a film having a thicker compressive stress;
To form a nozzle plate,
The nozzle plate and a flow path member forming a liquid chamber communicating with the nozzle are joined.

A method for manufacturing a liquid discharge head according to the present invention includes:
Forming a recess to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the metal plate is formed, and opening the nozzle;
Forming a film having a first compressive stress on both surfaces of the metal plate;
Forming a film having a second compressive stress on the surface on which the recess is formed;
To form a nozzle plate,
The nozzle plate and a flow path member forming a liquid chamber communicating with the nozzle are joined.

A method for manufacturing a liquid discharge head according to the present invention includes:
Forming a recess to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the metal plate is formed, and opening the nozzle;
Forming a film having a tensile stress on the polishing surface side of the metal plate;
Forming the film having the tensile stress on the surface side where the concave portion of the metal plate is formed of the same material as the film having the tensile stress on the polishing surface side; and
To form a nozzle plate,
The nozzle plate and a flow path member forming a liquid chamber communicating with the nozzle are joined.

A method for manufacturing a liquid discharge head according to the present invention includes:
Forming a recess to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the metal plate is formed, and opening the nozzle;
Forming a film having a first tensile stress on both surfaces of the metal plate;
Forming a film having a second tensile stress on the polished surface side;
To form a nozzle plate,
The nozzle plate and a flow path member forming a liquid chamber communicating with the nozzle are joined.

  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, bond quality by reducing the variation in the flatness of the nozzle plate forming with up less processing, improved joint reliability, improves droplet ejection characteristics.

According to the method of manufacturing a liquid ejection head according to the present invention, bond quality by reducing the variation in the flatness of the nozzle plate forming with up less processing, improved joint reliability, improves droplet ejection characteristics.

  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 formed.

FIG. 3 is a schematic exploded perspective view illustrating an example of an embodiment of a liquid discharge head according to the present invention including a nozzle plate according to the present invention. It is sectional explanatory drawing along the liquid chamber longitudinal direction of the head. It is a perspective explanatory view of the piezoelectric actuator of the head. It is sectional explanatory drawing of the actuator. FIG. 3 is an explanatory plan view of the nozzle plate of the liquid ejection head according to the first embodiment of the present invention as viewed from the liquid chamber side. FIG. 6 is a partial cross-sectional explanatory view of the flow path unit corresponding to the line AA in FIG. 5. FIG. 6 is a cross-sectional explanatory view taken along the line AA of FIG. 5 for explaining the manufacturing process of the nozzle plate of the liquid ejection head according to the first embodiment of the present invention. It is principal part expanded sectional explanatory drawing with which it uses for description of the effect of this embodiment. It is principal part expanded sectional explanatory drawing with which it uses for description of a comparative example. FIG. 6 is an explanatory plan view of a nozzle plate of a liquid ejection head according to a second embodiment of the present invention as viewed from the liquid chamber side. It is a fragmentary sectional view of the flow path unit corresponding to the BB line of FIG. FIG. 11 is a cross-sectional explanatory view of a portion corresponding to BB in FIG. 10 for explaining a manufacturing process of a nozzle plate of a liquid ejection head according to a second embodiment of the present invention. FIG. 13 is a similar cross-sectional explanatory diagram illustrating a process following FIG. 12. It is typical explanatory drawing with which it uses for description of the effect of the embodiment. FIG. 8 is a partial cross-sectional explanatory view of a flow path unit corresponding to the line BB in FIG. 6 of a liquid ejection head according to a third embodiment of the present invention. FIG. 8 is a cross-sectional explanatory view of a portion corresponding to the line BB in FIG. 6 for explaining a method for manufacturing a nozzle plate of a liquid ejection head according to a third embodiment of the present invention. 1 is a schematic configuration diagram illustrating an overall configuration of a mechanism unit as an example of an image forming apparatus according to the present invention. It is principal part plane explanatory drawing of the mechanism part. It is a whole block diagram which shows the other example of the image forming apparatus which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An embodiment of a liquid discharge head according to the present invention will be described with reference to FIGS. 1 is a schematic exploded perspective view of the head, FIG. 2 is a sectional explanatory view of the head along the longitudinal direction of the liquid chamber, FIG. 3 is a perspective explanatory view of the piezoelectric actuator, and FIG. 4 is a sectional explanatory view of the piezoelectric actuator. It is.

The liquid discharge head includes a nozzle plate 1, a flow path plate (flow path member) 2, a vibration plate member 3, a piezoelectric actuator 4, and a frame member 5 according to the present invention. A liquid chamber (flow path) unit 6 is constituted by the path plate 2 and the diaphragm member 3.
ing.

  A plurality of nozzles 11 for discharging droplets are formed on the nozzle plate 1 at a pitch of 600 dpi, for example. Four rows of nozzles 11 (referred to as “nozzle rows”) are arranged in four rows. Although not shown, a fluorine-based water repellent film is formed on the surface of the nozzle plate 1 on the droplet discharge side. The nozzle plate 1 is formed of a metal plate (member) such as SUS. In addition, the nozzle plate 1 can also be set as the structure which arrange | positioned the several sheets side by side instead of making one sheet.

  A liquid chamber 22 and the like communicating with the nozzle 11 are formed in the flow path plate 2 that is a flow path member. The liquid chambers 22 correspond to the respective nozzles 11 and are arranged in four rows corresponding to the respective nozzle rows. The flow path plate 2 is formed by pressing a metal plate such as SUS.

  A diaphragm-like vibration region (diaphragm portion) 31 corresponding to each liquid chamber 22 and forming one surface of each liquid chamber 22 is formed in the vibration plate member 3, and a convex portion 32 is formed in the vibration region 31. Has been. The diaphragm member 3 is formed of, for example, a multi-layer Ni electroformed member or a laminated member of a resin member and a metal member.

  The piezoelectric actuator 4 includes four stacked piezoelectric members 42A to 42D (hereinafter referred to as “piezoelectric member 42” when not distinguished from each other) in which a plurality of piezoelectric element columns 42a corresponding to the respective liquid chambers 22 are formed on one base member 41. As a signal transmission cable for arranging four rows of piezoelectric element columns 42a and transmitting drive signals to the end surface electrodes of the piezoelectric element columns 42a of the piezoelectric members 42 to the piezoelectric element columns 42a. FPC cables 43A to 43D (hereinafter referred to as “FPC cable 43” when not distinguished) are soldered together.

  Here, the piezoelectric member 42 is formed by alternately laminating piezoelectric layers and internal electrodes, and drawing the internal electrodes alternately to different end faces and performing half-cut dicing on the members connected to the end face electrodes to form grooves. Thus, a plurality of piezoelectric element columns 42a are integrally formed.

  In addition, since the side which becomes a common electrode among the end surface electrodes of the both end surfaces of the piezoelectric member 42 is routed to the same end surface as the end surface electrode on the individual electrode side through an internal electrode which is not cut, The FPC cable 43 can be soldered. In addition, here, a piezoelectric member in which a plurality of piezoelectric element columns 42a are integrated by half-cut dicing is used, but a configuration in which the piezoelectric element columns are completely divided into individual piezoelectric element columns may be employed. Further, the piezoelectric element columns 42a have a bi-pitch configuration in which every other piezoelectric element column 42a applies a driving signal and a non-driving piezoelectric element column as a support member that supports the liquid chamber interval wall, and each piezoelectric element column 42a. Can be any configuration of a normal pitch configuration in which driving piezoelectric element columns to which a driving signal is applied are used.

  The side of the base member 41 where the piezoelectric member 42 is joined is formed such that the cross-sectional shape in the direction orthogonal to the direction in which the piezoelectric element columns 42a are arranged (the direction along the rows of piezoelectric elements) is uneven, A piezoelectric member 42 is joined and disposed on the uppermost surface of 41a. Here, there are four rows of the piezoelectric element columns 42a, and two rows can be arranged on each convex portion 41a. Therefore, the cross-sectional shape of the base member 41 is a concave shape. The number of piezoelectric element columns is not limited to four, and may be one or more.

  Further, a through hole 44 is formed between the piezoelectric members 42B and 42C in the base member 41, and an FPC cable 43B connected to the piezoelectric member 42B not located at the end of the base member 41 and an FPC connected to the piezoelectric element member 42C. The cable 43 </ b> C is drawn out to the back side of the base member 41 (the side opposite to the side where the piezoelectric member 42 is joined) through the through hole 44. The FPC cable 43A connected to the piezoelectric member 42A located at the end of the base member 41 and the FPC cable 43D connected to the piezoelectric member 42D are pulled out along the side surface of the base member 41 as they are.

  The base member 41 can be made of, for example, resin, but is preferably a metal material. By adopting a highly rigid metal material, it is possible to suppress the vibration of the piezoelectric element column 42a from being transmitted to the main body. In addition, by forming the base member 41 with a metal material, the selection range of the processing method of the base member 41 is widened. For example, by adopting metal injection or drawing processing, the material and processing cost of the base member can be reduced. It becomes like this.

  The frame member 5 forms common liquid chambers 51 </ b> A, 51 </ b> B, 51 </ b> C, and 51 </ b> D that supply ink to the liquid chambers 22 through the supply ports 33 of the diaphragm member 3. Ink is supplied to the common liquid chambers 51A, 51B, 51C, and 52D from the outside through a supply path (not shown). The frame member 5 is formed with storage portions 52A and 52B for storing the base member 41, and the central portion 53 that forms the common liquid chambers 51B and 51C between the storage portions 52A and 52B penetrates the base member 41. It penetrates the hole 44. The frame member 5 is formed of, for example, a resin member. The frame member 5 can be divided into a plurality of members.

  In the liquid discharge head configured as described above, for example, by lowering the voltage applied to the piezoelectric element column 42a from the reference potential, the piezoelectric element column 42a contracts, and the vibration region 31 of the diaphragm member 3 descends to lower the liquid chamber 22. As the volume of the liquid expands, the ink flows into the liquid chamber 22, and then the voltage applied to the piezoelectric element column 42a is increased to extend the piezoelectric element column 42a, and the vibration region 31 is deformed in the direction of the nozzle 11 to thereby form the liquid. By contracting the volume of the chamber 22, the ink in the liquid chamber 22 is pressurized, and ink droplets are ejected (ejected) from the nozzle 11.

  Then, by returning the voltage applied to the piezoelectric element column 42a to the reference potential, the vibration region 31 is restored to the initial position, and the liquid chamber 22 expands to generate a negative pressure. The chamber 22 is filled with ink. Therefore, after the vibration of the meniscus surface of the nozzle 11 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Note that the driving method of the head is not limited to the above example (drawing-pushing), and striking or pushing can be performed depending on the direction of the drive waveform.

  Next, the liquid discharge head according to the first embodiment of the present invention will be described with reference to FIGS. 5 is an explanatory plan view of the nozzle plate of the head as viewed from the liquid chamber side, and FIG. 6 is a partial sectional explanatory view of the flow path unit corresponding to the line AA in FIG.

  As described above, the liquid ejection head includes the nozzle plate 1 on which the nozzles 11 for ejecting liquid droplets are formed and the liquid chamber 22 that communicates with the nozzles 11, and is opposite to the liquid ejection surface of the nozzle plate 1. And a vibration plate member 3 that forms a part of the wall surface of the liquid chamber 22 of the flow path plate 2.

  Here, the nozzle plate 1 is formed of a metal plate (nozzle base material) 301 having a plurality (four in this case) of nozzle rows 12A to 12D in which a plurality of nozzles 11 formed by pressing are arranged. ing.

  Films 360 and 361 having compressive stress with respect to the nozzle plate 301 are formed on both surfaces of the metal plate 301, and the thicknesses of the films 360 and 361 are liquids bonded to the flow path plate (flow path member) 2. The film 361 on the chamber surface side is formed thicker than the film 360 on the liquid ejection surface side.

  With this configuration, even when the nozzle plate 1 is formed by pressing a metal plate, the variation in the flatness of the nozzle plate 1 is reduced, and the quality and reliability of bonding with the flow path plate 2 are improved. In addition, the inclination of the nozzle 11 is also reduced, and the droplet ejection characteristics are improved.

Next, a manufacturing method of the liquid discharge head according to the first embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional explanatory view taken along the line AA of FIG. 5 for explaining the manufacturing process of the nozzle plate of the head.
First, as shown in FIG. 7A, a SUS base material (metal plate, nozzle base material) 301 having a thickness of 50 μm to be the nozzle plate 1 is prepared.

  Then, as shown in FIG. 7B, the base material 301 is set on the die 312 so that the liquid chamber surface side is the surface into which the punch 302 is driven, and the required number of punches 302 are driven into the base material 301 in the nozzle row direction. Thus, as shown in FIG. 7C, the base material 301 is formed with a recess 303 corresponding to the punch 302 in a portion to be the nozzle 11 of the nozzle row 12A, and a convex portion 307 is formed on the opposite surface. The Similarly, by moving the punch 302 (circled numbers 1 to 4 in the figure), the punches 302 are driven into the portions of the nozzle rows 12B, 12C, and 12D to become the nozzles 11, thereby forming the concave portions 304 to 306 corresponding to the punch 302, respectively. Convex portions 308 to 310 are formed on the opposite surface.

  At this time, due to the residual stress generated by driving the punch 302, the substrate 301 has a flatness h1 (deformation amount h1) at the edge portion between the nozzle rows 12B and 12C, as shown in FIG. In the portion, plastic deformation having a deformation amount H1 (flatness H1) whose deformation direction is random in the base material 11 occurs. That is, in the base material 11, a portion 14A that protrudes toward the liquid ejection surface at a certain portion and a portion 14B that protrudes toward the liquid chamber surface at a certain portion appear.

  In this embodiment, the distance between the nozzle rows 12A and 12B and between the nozzle rows 12C and 12D is small, so that the deformation amount due to punching is small. In detail, it is in the same uneven state as shown by the parts 14A and 14B, and the same uneven state as shown in the parts 14A and 14B appears more clearly when the inter-column distance is longer.

  Next, as shown in FIG.7 (d), the convex part 307-310 of the base material 301 is grind | polished using the tape grinding | polishing apparatus 315, and the recessed part 303-306 is penetrated to FIG.7 (e). As shown, the substrate 301 is formed with a row of nozzle holes 321 to 324 to be the nozzles 11. The polishing surface is a liquid discharge surface 351, and the opposite surface is a liquid chamber forming surface 350.

  However, since the residual stress is not relaxed even after this polishing step, the plastic deformation amounts H1 and h1 are maintained in the same state as in FIG.

Next, as shown in FIG. 7 (f), the SiO ₂ film 360 is formed on the liquid discharge surface (polishing surface) 351 as a film having compressive stress with respect to the base material 301, and the SiO ₂ film 361 is also formed on the liquid chamber surface 350. Form. At this time, the film thickness is such that the liquid ejection surface <the liquid chamber surface, that is, the film thickness of the SiO ₂ film 360 <SiO ₂ film 361.

  Note that an oxide film formed by CVD, such as an NSG film, a PSG film, a BPSG film, or a TEOS film, can also be used as the film having compressive stress with respect to the base material 301. In addition, as for the order of forming the film having compressive stress, either the liquid discharge surface or the liquid chamber surface may be formed first.

The SiO ₂ films 360 and 361 can be formed by, for example, a CVD method or thermal oxidation. Here, the SiO ₂ films 360 and 361 are formed by the CVD method. As specific film forming conditions, using a sputtering apparatus manufactured by Material Research Corporation, the degree of vacuum is 1 × 10 −5 Torr, the RF power is 1.8 kW, the gas pressure is 15 mTorr, the O ₂ partial pressure is 10%, and the scan speed is 10 cm / min. Thus, the SiO ₂ film 360 on the droplet discharge surface 350 side has a thickness of 0.1 μm, and the SiO ₂ film on the liquid chamber surface 351 side has a thickness of 0.2 μm.

At this time, since the SiO ₂ films 360 and 361 have compressive stress, the portion 14A that protrudes toward the liquid ejection surface between the nozzle rows 12B and 12C due to the film stress due to the film thickness difference protrudes toward the liquid chamber surface. It becomes.

  As a result, the portion between the nozzle rows 12B and 12C has a uniform shape that is convex on the side surface of the liquid chamber at any position in the nozzle plate 1 as in the region 14B, and the flatness near the nozzle holes is high. Improved (H2 <H1).

  Further, between the nozzle rows 12A and 12B and between the nozzle rows 12C and 12D, the liquid chamber surface is convex as in the portion 14B.

  Therefore, the nozzle plate 1 and the flow path plate 2 are joined, the flow path plate 2 and the vibration plate member 3 are joined, and the actuator unit is joined to complete the head.

Next, the effect of this invention is demonstrated with reference to FIG.8 and FIG.9. FIG. 8 is an enlarged cross-sectional explanatory view of a main part for explaining the present embodiment, and FIG. 9 is an enlarged explanatory cross-sectional view of a main part for explaining a comparative example.
First, as described above, when nozzles (nozzle holes) are formed in a metal plate by pressing, as shown in FIG. 9A, the base material 301 (nozzle plate 1) undergoes plastic deformation during the nozzle hole formation process. As for the direction of this plastic deformation, the portion 14B that protrudes toward the liquid chamber surface or the portion 14A that protrudes toward the liquid discharge surface is randomly generated, and the direction of the protrusion is not constant.

  Therefore, as a result, a difference occurs in the shape around the nozzle hole 11 (the flatness varies), and the base material 301 is directly joined to the flow path plate 2 with the adhesive 61 as the nozzle plate 1. In the state before joining, there is a gap having a gap a (a> b) in the portion 14A where the convex direction is the liquid discharge surface direction and the portion 14B where the convex direction is the liquid chamber surface direction.

  Therefore, as shown in FIG. 9B, when the nozzle plate 1 and the flow path plate 2 are joined, variation occurs in the joined state, and stable joining quality cannot be obtained. Further, by performing bonding in such a non-uniform state, the nozzle hole 11 is inclined, and droplet ejection bending occurs. That is, the nozzle hole 11 is inclined at an inclination angle θ with respect to the line 500 perpendicular to the liquid ejection surface.

  In this case, if the inclination angle θ of the nozzle hole 11 is uniform, it can be corrected by a print correction technique (software correspondence). However, since the direction of plastic deformation is random as described above, the inclination angle θ also varies. For this reason, it is difficult to cope with only the print correction technique, and stable print quality cannot be obtained.

  On the other hand, in the above embodiment, as shown in FIG. 8A, the direction of plastic deformation of the base material 301 is aligned with the liquid chamber surface side (becomes constant), so the shape near the nozzle hole 11 is uniform. (The intervals a and b are substantially the same (including the same)). Therefore, as shown in FIG. 8 (b), the variation in flatness of the nozzle plate 1 is reduced, and a stable joining quality can be obtained. In addition, the inclination of the nozzle hole 11 is also reduced, and good droplet discharge is achieved. The characteristics are obtained and the printing quality is improved.

  In addition, when a compressive stress film having a film thickness difference is formed on both sides using a silicon substrate as the nozzle base material as in the above embodiment, the flat nozzle base material is warped. This is applicable only when the material has plastic deformation (metal plate or the like).

  In this way, a nozzle plate having a plurality of nozzle rows in which a plurality of nozzles formed by press working are arranged, and a liquid chamber in which the nozzles communicate with each other are formed on the surface opposite to the liquid ejection surface of the nozzle plate. The nozzle plate is formed of a metal plate, and a film having a compressive stress with respect to the metal plate is formed on both surfaces of the metal plate. By adopting a configuration in which the side to be joined is formed thicker than the liquid discharge side, the variation in the flatness of the nozzle plate formed by press working is reduced, and the joining quality and joining reliability are improved. The droplet discharge characteristics are improved.

  In the above embodiment, a film that generates a compressive stress is formed on the entire surface of the nozzle substrate. However, for example, the compressive stress is partially applied only between the nozzle rows 12B and 12C described above. The resulting film can also be formed.

  In addition, a step of forming a concave portion to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working, and a convex portion generated on a surface opposite to the surface on which the concave portion of the metal plate is formed are polished to form a nozzle. It is the same material as the step of opening, the step of forming a film having a compressive stress on the polishing surface side of the metal plate, and the film having the compressive stress on the polishing surface side on the surface side where the concave portion of the metal plate is formed. Forming a film having a thick compressive stress, forming a nozzle plate, and bonding the nozzle plate and a flow path member forming a liquid chamber in which the nozzle communicates, The variation in the flatness of the nozzle plate formed by processing is reduced, the joining quality and joining reliability are improved, and the droplet ejection characteristics are improved.

  As for the formation of a film having a compressive stress, a film having a first compressive stress (first compressive stress film) is collectively formed on the liquid discharge surface and the liquid chamber surface of the nozzle substrate to increase the film thickness. A film having a second compressive stress on the surface of the liquid chamber (the second compressive stress film may be laminated on the first compressive stress film, and the film thickness on the liquid chamber side may be formed to a required film thickness. it can.

  In this way, it is possible to shorten the film formation process time. Further, the second compressive stress film can be formed of a material different from that of the first compressive stress film. For example, the second compressive stress film can be a functional film such as a bonding improvement film.

  That is, a step of forming a concave portion that becomes a nozzle constituting a plurality of nozzle rows from one surface of a metal plate by press working, and a convex portion generated on a surface opposite to the surface on which the concave portion of the metal plate is formed are polished to form a nozzle. The step of opening, the step of forming a film having a first compressive stress on both surfaces of the metal plate, and the step of forming a film having a second compressive stress on the surface on which the concave portion is formed are performed. And forming a nozzle plate and a flow path member that forms a liquid chamber that communicates with the nozzle, thereby reducing variations in the flatness of the nozzle plate formed by press working, and joining quality and joining reliability. And the droplet ejection characteristics are improved.

Next, a liquid ejection head according to a second embodiment of the present invention will be described with reference to FIGS. 10 is a plan view illustrating the nozzle plate of the head as viewed from the liquid chamber side, and FIG. 11 is a partial cross-sectional view of the flow path unit corresponding to the line BB in FIG.
Here, the nozzle plate 1 is formed with four nozzle rows 12A to 12D in which a plurality of nozzles 11 are arranged as described above. And two recessed part rows 13A and 13B in which a plurality of recessed parts 13 arranged in parallel with these four nozzle rows 12A to 12D are arranged are opposite to the central axis b of the entire four nozzle arrays 12A to 12D. Is arranged.

  In this case, the recess rows 13A and 13B are arranged outside the outermost nozzle rows 12A and 12D in the direction orthogonal to the nozzle arrangement direction. Further, in the case where a plurality of nozzle rows 12 are arranged and the nozzles are arranged in a staggered manner, when the concave portion 13 is formed in a portion corresponding to the liquid chamber interval wall, the arrangement is asymmetric with respect to the central axis b. In addition, the nozzle 11 and the recessed part 13 of the nozzle plate 1 are formed by press work.

  With such a configuration, even if the nozzle plate 1 is formed by press working, deformation due to the press working can be suppressed, so that the joining quality and joining reliability with the flow path plate 2 are improved.

  The nozzle rows 12A and 12B are used as one nozzle group, and the recess rows 13A and 13B are arranged on both sides of the nozzle groups 12A and 12B. Similarly, the nozzle rows 12C and 12D are also used as one nozzle group. 13A and 13B can also be arranged.

Next, a method for manufacturing a liquid discharge head according to the second embodiment of the present invention will be described with reference to FIGS. 12 is a cross-sectional explanatory view of a portion corresponding to BB in FIG. 10 for explaining the manufacturing process of the nozzle plate of the head, and FIG. 13 is a similar cross-sectional explanatory view explaining the process following FIG. .
First, the steps from FIG. 12A to FIG. 12E are the same as those in FIG. 7A to FIG. 7E of the first embodiment, and a description thereof will be omitted.

  Then, as shown in FIG. 13A, the base material 301 is sandwiched between the pressing members 335, and the punches 330 and 331 are placed outside the nozzle holes 321 and 324 corresponding to the nozzle rows 12A and 12D. The nozzle holes 321 and 324 corresponding to 12D are driven in parallel with the row.

  As a result, as shown in FIG. 13B, recess rows 13A and 13B in which a plurality of recesses 13 are arranged are formed on the liquid chamber surface side. When the recesses 13 (recess rows 13A and 13B) are formed, stress is generated in the nozzle plate 301 in the direction to cancel the plastic deformation described above. As a result, the flatness of the tip edge portion of the nozzle plate 1 becomes h2, The flatness h1 due to the deformation is smaller (h2 <h1), and the flatness of the substrate is improved.

  In addition, as for the order of forming the recess rows 13A and 13B, there may be a time difference between the punches 330 and 331, but the flatness can be further improved by driving them simultaneously.

Then, as shown in FIG. 13C, as in the first embodiment, an SiO ₂ film 360 as a film having a compressive stress with respect to the substrate 301 is formed on the liquid discharge surface (polishing surface) 351, and the liquid chamber. Similarly, the SiO ₂ film 361 is formed on the surface 350. At this time, the film thickness is such that the liquid discharge surface <the liquid chamber surface, that is, the film thickness of the SiO ₂ film 360 <the SiO ₂ film 361.

At this time, since the SiO ₂ films 360 and 361 have compressive stress, the portion 14A that protrudes toward the liquid ejection surface between the nozzle rows 12B and 12C due to the film stress due to the film thickness difference protrudes toward the liquid chamber surface. It becomes.

  As a result, the portion between the nozzle rows 12B and 12C has a uniform shape that is convex on the side surface of the liquid chamber at any position in the nozzle plate 1 as in the region 14B, and the flatness near the nozzle holes is high. Improved (H2 <H1).

  Further, between the nozzle rows 12A and 12B and between the nozzle rows 12C and 12D, the liquid chamber surface is convex as in the portion 14B.

  And in this embodiment, since the flatness of the edge part of the nozzle plate 1 is also improved compared with the case of the said 1st Embodiment, a higher quality nozzle plate than the said 1st Embodiment can be obtained.

  That is, when the nozzle (nozzle hole) is formed by press working as described above, the base material 301 (nozzle plate 1) undergoes plastic deformation during the nozzle hole formation process, and the degree of this plastic deformation is not necessarily constant, and as a result As a result, the flatness varies. Here, the configuration of the first embodiment in which the recess rows 13A and 13B shown in FIG. 14A are not provided and the configuration of the first embodiment in which the recess rows 13A and 13B shown in FIG. In this case, the latter is relatively less uneven in flatness. In FIG. 14, for the sake of simplification, an example in which the convex direction between the nozzle rows 12B and 12C is one direction is shown.

  Next, a liquid discharge head and a method for manufacturing the same according to a third embodiment of the present invention will be described with reference to FIGS. 15 is a partial sectional explanatory view of the flow path unit corresponding to the BB line of FIG. 6 of the head, and FIG. 16 is a BB line of FIG. 6 for explaining the manufacturing process of the nozzle plate of the head. It is sectional explanatory drawing of the corresponding part.

  In this embodiment, films 560 and 561 having tensile stress with respect to the nozzle plate 301 are formed on both surfaces of the metal plate 301 constituting the nozzle plate 1, and the thicknesses of the films 560 and 561 are set on the liquid ejection surface side. The film 560 is formed thicker than the film 561 on the liquid chamber surface side.

  As the film having tensile stress, for example, a nitride film formed by LPCVD, an SOG film subjected to baking, or the like can be used.

  Therefore, the liquid discharge surface between the nozzle rows 12B and 12C is caused by the film stress due to the film thickness difference between the film 560 on the liquid discharge surface side and the film 561 on the liquid chamber surface side, as in the first and second embodiments. The portion 14A that is convex to the side is convex to the liquid chamber surface side (see FIG. 16), and variations in flatness are reduced.

  In addition, the manufacturing process of the nozzle plate in the manufacturing method of the liquid discharge head according to the present embodiment is performed after the processes of FIGS. 7A to 7E are performed, and then, as shown in FIG. A film 560 is formed on the liquid discharge surface side, and a film 561 is formed on the liquid chamber surface side. Note that the order of forming the films 560 and 561 may be any surface first.

  In this way, a nozzle plate having a plurality of nozzle rows in which a plurality of nozzles formed by press working are arranged, and a liquid chamber in which the nozzles communicate with each other are formed on the surface opposite to the liquid ejection surface of the nozzle plate. The nozzle plate is formed of a metal plate, and a film having tensile stress with respect to the metal plate is formed on both surfaces of the metal plate, and the thickness of the film is on the liquid discharge surface side. By adopting a configuration that is thicker than the liquid ejection surface side, the variation in the flatness of the nozzle plate formed by press working is reduced, the joining quality and joining reliability are improved, and the droplet ejection characteristics are improved. improves.

  In addition, a step of forming a concave portion to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working, and a convex portion generated on a surface opposite to the surface on which the concave portion of the metal plate is formed are polished to form a nozzle. It is the same material as the step of opening, the step of forming a film having tensile stress on the polishing surface side of the metal plate, and the film having tensile stress on the polishing surface side on the surface side where the concave portion of the metal plate is formed. Forming a thin film having a tensile stress, forming a nozzle plate, and joining the nozzle plate and a flow path member forming a liquid chamber in which the nozzle communicates, The variation in the flatness of the nozzle plate formed by processing is reduced, the joining quality and joining reliability are improved, and the droplet ejection characteristics are improved.

  As for the formation of a film having a tensile stress, a film having a first tensile stress (first tensile stress film) is collectively formed on the liquid discharge surface and the liquid chamber surface of the nozzle substrate to increase the film thickness. A film having a second tensile stress (second tensile stress film) is formed on the liquid ejection surface by laminating on the first tensile stress film, and the film thickness on the liquid ejection surface side is formed to a required film thickness. You can also.

  In this way, it is possible to shorten the film formation process time. Further, the second tensile stress film can be formed of a material different from that of the first tensile stress film. For example, the second tensile stress film can be a functional film such as a bonding improvement film.

  A head-integrated liquid cartridge (cartridge-integrated head) can be obtained by integrating the liquid discharge head described above and a tank that supplies liquid to the liquid discharge head.

Next, an example of the image forming apparatus according to the present invention including the liquid ejection head according to the present invention will be described with reference to FIGS. FIG. 17 is a schematic configuration diagram for explaining the overall configuration of the mechanism portion of the apparatus, and FIG. 18 is a plan view for explaining a main portion of the mechanism portion.
This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in the main scanning direction by main and slave guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 221A and 221B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

  The carriage 233 includes a plurality of recording heads 234 including the liquid discharge head unit according to the present invention for discharging ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). Nozzle rows consisting of these 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.

  The recording head 234 is configured by attaching liquid ejection heads 234a and 234b each having two nozzle rows to one base member, and one nozzle row of one head 234a has a black (K) droplet. The other nozzle row ejects cyan (C) droplets, the other nozzle row of the other head 234b ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets. . Note that, here, a two-head configuration is used to eject four color droplets, but a liquid ejection head for each color may be provided.

  The carriage 233 is equipped with sub tanks 235a and 235b (referred to as “sub tank 235” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 234. The sub tank 235 is supplied with ink of each color from the ink cartridge 210 of each color by the supply unit 224 via the supply tube 236 of each color.

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

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the recording head 234, a guide member 245 for guiding the sheet 242, a counter roller 246, a conveyance guide member 247, and a tip pressure roller. And a conveying belt 251 which is a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the recording head 234.

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

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

  A double-sided unit 271 is detachably attached to the back surface of the apparatus main body. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.

  Further, a maintenance / recovery mechanism 281 for maintaining and recovering the nozzle state of the recording head 234 is disposed in a non-printing area on one side in the scanning direction of the carriage 233. The maintenance / recovery mechanism 281 includes cap members (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the recording head 234, and nozzle surfaces. A wiper blade 283 that is a blade member for wiping the ink, and an empty discharge receiver 284 that receives liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge thickened ink. Yes.

  In addition, in the non-printing area on the other side of the carriage 233 in the scanning direction, idle ejection that receives droplets when performing idle ejection that ejects droplets that do not contribute to recording in order to discharge ink that has been thickened during recording or the like. A receiver 288 is disposed, and the idle discharge receiver 288 is provided with an opening 289 along the nozzle row direction of the recording head 234 and the like.

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

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

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

  As described above, since the image forming apparatus includes the liquid discharge head according to the present invention having high bonding quality and high reliability as the recording head, it is possible to form a high-quality image with little variation in droplet discharge characteristics. it can.

Next, another example of the image forming apparatus according to the present invention including the liquid ejection head according to the present invention will be described with reference to FIG. FIG. 19 is a schematic configuration diagram of the entire mechanism unit of the apparatus.
This image forming apparatus is a line type image forming apparatus, has an image forming unit 402 and the like inside the apparatus main body 401, and can supply a large number of recording media (sheets) 403 on the lower side of the apparatus main body 401. A paper tray 404 is provided, a sheet 403 fed from the sheet feeding tray 404 is taken in, a required image is recorded by the image forming unit 402 while the sheet 403 is conveyed by the conveying mechanism 405, and then the side of the apparatus main body 401. The paper 403 is discharged to a paper discharge tray 406 attached to the printer.

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

  Here, the image forming unit 402 is, for example, four full-line liquids according to the present invention that discharge droplets of each color of black (K), cyan (C), magenta (M), and yellow (Y). The recording heads 411k, 411c, 411m, and 411y (which are referred to as “recording heads 411” when the colors are not distinguished) are configured with ejection heads. The head holder 413 is attached.

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

  Here, the recording head 411 is arranged to eject droplets of each color in the order of blank, cyan, magenta, and yellow from the upstream side in the paper conveyance direction, but the arrangement and the number of colors are not limited to this. Further, as the line type head, one or a plurality of heads provided with a plurality of nozzle rows for discharging droplets of each color at a predetermined interval can be used, or a head and a liquid cartridge for supplying ink to the head are integrated. Or a separate body.

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

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

  The conveyance mechanism 405 includes an endless conveyance belt 433 that is stretched between a conveyance roller 431 that is a driving roller and a driven roller 432, a charging roller 434 that charges the conveyance belt 433, and an image forming unit 402. A platen member 435 that maintains the flatness of the conveying belt 433 at the opposite portion, a pressing roller 436 that presses the paper 403 fed from the conveying belt 433 against the conveying roller 431 side, and other ink (not shown) that adheres to the conveying belt 433. It has a cleaning roller made of a porous body or the like as a cleaning means for removing.

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

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

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

  As described above, the image forming apparatus includes the liquid discharge head according to the present invention having high bonding quality and high reliability as the recording head, so that there is little variation in droplet discharge characteristics, and high-speed and high-quality images can be obtained. Can be formed.

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

1 Nozzle plate 2 Channel member (channel plate)
DESCRIPTION OF SYMBOLS 3 Diaphragm member 4 Piezoelectric actuator 5 Frame member 11 Nozzle 12, 12A-12D Nozzle row 13 Recess 13A, 13B Recess row 22 Liquid chamber 22 Liquid chamber interval wall 31 Vibrating region 41 Base member 42A, 42B, 42C, 42D Piezo member 42a Piezoelectric element column 233 Carriage 234a, 234b Recording head 360, 361 Film having compression stress 411k, 411c, 411m, 411y Recording head 560, 561 Film having tensile stress

Claims (9)

A nozzle plate having a plurality of nozzle rows in which a plurality of nozzles formed by pressing is arranged, and a liquid chamber in which the nozzles communicate with each other are formed, and are joined to a surface opposite to the liquid discharge surface of the nozzle plate. In a liquid discharge head having a flow path member,
The nozzle plate is formed of a metal plate,
Films having compressive stress on the metal plate are formed on both surfaces of the metal plate,
The liquid discharge head according to claim 1, wherein a thickness of the film is formed so that a surface side bonded to the flow path member is thicker than a liquid discharge surface side. The liquid discharge head according to claim 1, wherein the film is a film made of SiO ₂ . A nozzle plate having a plurality of nozzle rows in which a plurality of nozzles formed by pressing is arranged, and a liquid chamber in which the nozzles communicate with each other are formed, and are joined to a surface opposite to the liquid discharge surface of the nozzle plate. In a liquid discharge head having a flow path member,
The nozzle plate is formed of a metal plate,
Films having a tensile stress on the metal plate are formed on both surfaces of the metal plate,
The thickness of the membrane, the liquid discharge head is characterized in that towards the liquid discharge side is thicker than the channel member and the surface side that will be joined. The liquid ejection head according to claim 1, wherein the film is formed only in a portion between the nozzle rows.
Forming a recess to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the metal plate is formed, and opening the nozzle;
Forming a film having a compressive stress on the polished surface side of the metal plate;
Forming the film having the compressive stress on the polishing surface side on the surface side where the concave portion of the metal plate is formed, and forming a film having a thicker compressive stress;
To form a nozzle plate,
A method of manufacturing a liquid discharge head, comprising joining the nozzle plate and a flow path member forming a liquid chamber in communication with the nozzle. Forming a recess to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the metal plate is formed, and opening the nozzle;
Forming a film having a first compressive stress on both surfaces of the metal plate;
Forming a film having a second compressive stress on the surface on which the recess is formed;
To form a nozzle plate,
A method of manufacturing a liquid discharge head, comprising joining the nozzle plate and a flow path member forming a liquid chamber in communication with the nozzle. Forming a recess to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the metal plate is formed, and opening the nozzle;
Forming a film having a tensile stress on the polishing surface side of the metal plate;
Forming the film having the tensile stress on the surface side where the concave portion of the metal plate is formed of the same material as the film having the tensile stress on the polishing surface side; and
To form a nozzle plate,
A method of manufacturing a liquid discharge head, comprising joining the nozzle plate and a flow path member forming a liquid chamber in communication with the nozzle. Forming a recess to be a nozzle constituting a plurality of nozzle rows from one surface of the metal plate by press working;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the metal plate is formed, and opening the nozzle;
Forming a film having a first tensile stress on both surfaces of the metal plate;
Forming a film having a second tensile stress on the polished surface side;
To form a nozzle plate,
A method of manufacturing a liquid discharge head, comprising joining the nozzle plate and a flow path member forming a liquid chamber in communication with the nozzle.   An image forming apparatus comprising the liquid discharge head according to claim 1.

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