JP2011183728A - Nozzle plate, method for manufacturing nozzle plate, liquid discharging head, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a nozzle plate plastically deforms so that bonding quality and reliability are deteriorated when forming holes being nozzles of the nozzle plate by press machining. <P>SOLUTION: A nozzle row 12 constituted by arranging a plurality of nozzles 11 is formed in the nozzle plate 1, two recessed rows 13A, 13B constituted by arranging a plurality of recesses 13 aligned in parallel with the nozzle row 12 are arranged at opposite sides in a direction orthogonal to a nozzle arranging direction while sandwiching the center axis a of the nozzle line 12, the nozzles 11 and the concave parts 13 are formed by press machining. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention particularly relates to a press-processed nozzle plate, a method for manufacturing the nozzle plate, a liquid discharge head including the nozzle plate, and an image forming apparatus.

  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 one, but 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) for forming nozzles (nozzle holes) for discharging liquid droplets constituting a liquid discharge head, there is known one in which nozzle holes are formed by pressing a metal plate such as SUS. .

  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).

  In addition, for each nozzle or nozzle group, there is one in which a recess that penetrates the nozzle plate and exposes the pressure chamber plate is formed (Patent Document 2).

JP 2006-224619 A JP 2008-068500 A

  However, when the nozzle is formed by press working as described above, the base material (member forming the nozzle) is deformed. When the nozzle plate is deformed, the nozzle plate is bonded to a flow channel member that forms a liquid chamber (individual flow channel) that communicates with the nozzle, so that a large amount of adhesive is applied to the bonding failure or bonding with the flow channel member. Causes the adhesive to protrude into the liquid chamber (which leads to variations in droplet discharge characteristics, etc.).

  Further, as described above, by providing a through hole around the nozzle hole, the distortion at the time of joining the nozzle plate and the flow path member can be reduced, but the distortion of the nozzle plate itself is not reduced.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to reduce the degree of deformation of a nozzle plate formed by pressing and improve the bonding quality and the bonding reliability.

In order to solve the above problems, the nozzle plate according to the present invention is:
In a nozzle plate having a nozzle row in which a plurality of nozzles for discharging droplets are arranged and joined to a flow path member forming a liquid chamber in which the nozzles communicate with each other,
At least two recess rows in which a plurality of recesses arranged in parallel with the nozzle row are arranged on the surface on the liquid chamber side are arranged on the opposite side across the central axis of the nozzle row.

The nozzle plate according to the present invention is:
In a nozzle plate having a nozzle row group composed of a plurality of nozzle rows in which a plurality of nozzles for discharging droplets are arranged, and joined to a flow path member forming a liquid chamber in communication with the nozzles,
On the surface of the liquid chamber, at least two recess rows in which a plurality of recesses arranged in parallel with the nozzle row are arranged on the opposite side across the central axis of the nozzle row group. .

  Here, the said recessed part can be set as the structure provided facing parts other than the liquid chamber of the said flow-path member.

The manufacturing method of the nozzle plate according to the present invention is as follows:
In a manufacturing method of a nozzle plate having a nozzle row in which a plurality of nozzles for discharging liquid droplets are arranged and joined to a flow path member that forms a liquid chamber that communicates with the nozzles,
Forming a recess to be the nozzle on the surface of the substrate on the liquid chamber side by pressing;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the substrate is formed, and opening the nozzle;
On the surface of the substrate on the liquid chamber side, at least two recess rows in which a plurality of recesses arranged in parallel with the nozzle row are arranged are formed by pressing on the opposite side to the central axis of the nozzle row. And a process of
Are configured to perform sequentially.

The manufacturing method of the nozzle plate according to the present invention is as follows:
In a manufacturing method of a nozzle plate having a nozzle row group composed of a plurality of nozzle rows in which a plurality of nozzles for discharging droplets are arranged and joined to a flow path member that forms a liquid chamber that communicates with the nozzles,
Forming a recess to be a nozzle constituting the plurality of nozzle rows on the surface of the substrate on the liquid chamber side by press working; and
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the substrate is formed, and opening the nozzle;
On the surface of the substrate on the liquid chamber side, at least two recess rows in which a plurality of recesses arranged in parallel with the nozzle rows are arranged are pressed on the opposite side with respect to the central axis of the nozzle row group. Forming, and
Are configured to perform sequentially.

  The liquid discharge head according to the present invention includes the nozzle plate according to the present invention.

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

  According to the nozzle plate of the present invention, at least two recess rows in which a plurality of recesses arranged in parallel with the nozzle row are arranged on the surface on the liquid chamber side are arranged on the opposite side across the central axis of the nozzle row. Since it is configured as described above, deformation due to press working is suppressed, and the joining quality and joining reliability are improved.

  According to the nozzle plate of the present invention, at least two recess rows in which a plurality of recesses arranged in parallel with the nozzle row are arranged on the surface on the liquid chamber side, on the opposite side across the central axis of the nozzle row group. Since the arrangement is arranged, deformation due to press working is suppressed, and bonding quality and bonding reliability are improved.

  According to the method for manufacturing a nozzle plate according to the present invention, the step of forming a recess to be a nozzle on the surface on the liquid chamber side of the substrate by press working and the surface opposite to the surface on which the recess of the substrate was formed occurred. The step of polishing the convex part and opening the nozzle, and at least two concave part rows in which concave parts arranged in parallel with the nozzle row are arranged on the liquid chamber side surface of the substrate with respect to the central axis of the nozzle row Since the step of forming by pressing on the opposite side is sequentially performed, a nozzle plate in which deformation due to pressing is suppressed is obtained, and the bonding quality and bonding reliability are improved.

  According to the method for manufacturing a nozzle plate according to the present invention, a step of forming recesses that serve as nozzles constituting a plurality of nozzle rows on the surface of the substrate on the liquid chamber side, and a surface on which the recesses of the substrate are formed A step of opening a nozzle by polishing a convex portion generated on the surface opposite to the surface, and at least two concave rows in which concave portions arranged in parallel with the nozzle row are arranged on the surface of the substrate on the liquid chamber side, Since the step of forming by pressing on the opposite side across the central axis of the row group is sequentially performed, a nozzle plate with suppressed deformation by pressing can be obtained, and the bonding quality and bonding reliability are improved. .

  According to the liquid discharge head according to the present invention, since the nozzle plate according to the present invention is provided, the reliability is improved and the variation in the droplet discharge characteristics is reduced.

  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. It is plane explanatory drawing which looked at the nozzle plate in 1st Embodiment of this invention from the liquid chamber side. FIG. 6 is a partial cross-sectional explanatory view corresponding to the cross section taken along line AA of FIG. 5 of the flow path unit including the same nozzle plate. It is a fragmentary sectional view used for description of the manufacturing method of the nozzle plate concerning a 1st embodiment of the present invention. It is plane explanatory drawing which looked at the nozzle plate in 2nd Embodiment of this invention from the liquid chamber side. It is a fragmentary sectional view equivalent to the BB line section of Drawing 8 of a channel unit containing the same nozzle board. It is a partial cross section explanatory drawing used for description of the manufacturing method of the nozzle plate which concerns on 2nd Embodiment of this invention. It is explanatory drawing with which it uses for description of the variation in the flatness of a nozzle plate, and nozzle inclination. It is explanatory drawing similarly used for description of nozzle inclination. It is plane explanatory drawing with which it uses for description of 3rd Embodiment of this invention. FIG. 14 is a cross-sectional explanatory view taken along the line DD in FIG. 13. 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 provided with a nozzle plate 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 pressurized liquid chamber 22 and the like that communicate 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, the base member 41 is formed with a through hole 44 between the piezoelectric element members 42B and 42C, and connected to the piezoelectric element member 42C and the FPC cable 43B connected to the piezoelectric member 42B not located at the end of the base member 41. The FPC 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 nozzle plate 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 as viewed from the liquid chamber side, and FIG. 6 is a partial cross-sectional explanatory view of the flow path unit corresponding to the line AA in FIG. Here, an example in which the number of nozzle rows is one will be described, but the same reference numerals as those used in the description of the liquid ejection head are used.

  The nozzle plate 1 is formed with a nozzle row 12 in which a plurality of nozzles 11 are arranged. Two recess rows 13 </ b> A and 13 </ b> B in which a plurality of recesses 13 arranged in parallel with the nozzle row 12 are arranged on the opposite side across the central axis a of the nozzle row 12.

  In this case, the recess rows 13A and 13B are arranged outside the nozzle row 12 in a direction orthogonal to the nozzle arrangement direction. In addition, when the nozzle row 12 is one row, it is preferable to form a symmetrical arrangement with respect to the central axis a when the concave portion 13 is formed in a portion corresponding to the liquid chamber interval wall as will be described later. 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.

Next, the manufacturing method of the nozzle plate according to the first embodiment of the present invention will be described with reference to FIG. 7 is a cross-sectional explanatory view taken along the line AA in FIG.
First, as shown to Fig.7 (a), the 50-micrometer-thick SUS base material 101 used as the nozzle plate 1 is prepared.

  Then, as shown in FIG. 7B, the base material 101 is set on the die 112 so that the side surface of the liquid chamber becomes a surface for punching the punch 102, and the necessary number of punches 102 are driven into the base material 101 in the nozzle row direction. Thus, as shown in FIG. 7C, the base material 101 is formed with the concave portion 103 corresponding to the punch 102 in the portion to be the nozzle hole 11 and the convex portion 104 on the opposite surface.

  Next, as shown in FIG. 7D, by using the tape polishing apparatus 105, the convex portion 104 of the base material 101 is polished and penetrated through the concave portion 103, so that the base is shown in FIG. A row of nozzle holes 106 to be a plurality of nozzles 11 is formed in the material 101.

  At this stage, since the punch 101 is driven, plastic deformation due to residual stress occurs in the base material 101 and this is not eliminated even after polishing. Therefore, the flatness of the base material 101 (two when sandwiched between two parallel surfaces). The distance between the surfaces (flatness) is H1.

  Therefore, as shown in FIG. 7 (f), the base material 101 is sandwiched between the pressing members 115, and the punches 110 are sequentially driven in parallel to the rows of the nozzle holes 106 on both sides of the nozzle holes 106.

  As a result, as shown in FIG. 7G, 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 1 in the direction of canceling the plastic deformation described above. As a result, the flatness of the nozzle plate 1 becomes H2, and the flatness due to the initial deformation. The deformation amount is smaller than H1 (H2 <H1).

  In addition, as for the order of forming the recess rows 13A and 13B, there may be a time difference between the punches 110 and 110, but the flatness can be further improved by driving them simultaneously.

  And as shown in FIG. 6 mentioned above, the stable joining quality is securable by joining the nozzle plate 1 with high flatness with the flow-path plate 2. FIG.

Next, a nozzle plate according to a second embodiment of the present invention will be described with reference to FIGS. 8 is an explanatory plan view of the nozzle plate as viewed from the liquid chamber side, and FIG. 9 is an explanatory sectional view taken along line BB in FIG.
As described above, the nozzle plate 1 is formed with the nozzle row group 15 including the four nozzle rows 12A to 12D in which the plurality of nozzles 11 are arranged. And two recessed part row | line | columns 13A and 13B by which the several recessed part 13 arranged in parallel with these four nozzle row | line | columns 12A-12D was arranged are the four nozzle row 12A-12D whole, ie, the central axis of the nozzle row group 15 It is arrange | positioned on the opposite side with respect to b.

  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, when the nozzle row 12 is a plurality of rows and the nozzles are arranged in a staggered manner, if the concave portion 13 is formed in a portion corresponding to the liquid chamber interval wall as will be described later, the arrangement becomes 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 nozzle plate according to a second embodiment of the present invention will be described with reference to FIG. 10A to 10G are cross-sectional explanatory views of a portion corresponding to BB in FIG.
First, as shown to Fig.10 (a), the 50-micrometer-thick SUS base material 101 used as the nozzle plate 1 is prepared.

  Then, as shown in FIG. 10B, the base material 301 is set on the die 312 so that the side surface of the liquid chamber becomes the surface for punching the punch 302, and the necessary number of punches 302 are driven into the base material 301 in the nozzle row direction. Thus, as shown in FIG. 10C, the base material 301 is formed with a concave portion 303 corresponding to the punch 302 in a portion to be the nozzle 11 of the nozzle row 12A and a convex portion 307 on the opposite surface. . Similarly, while moving the punch 302 (numerals 1 to 4 with circles in the figure), the portions of the nozzle rows 12B, 12C, and 12D that are to become the nozzles 11 are driven to form the recesses 304 to 306 corresponding to the punch 302, respectively. Convex portions 308 to 310 are formed on the opposite surface.

  Next, as shown in FIG. 10D, the tape polishing apparatus 315 is used to polish the convex portions 307 to 310 of the base material 301 and penetrate the concave portions 303 to 306, thereby showing the configuration shown in FIG. As described above, the substrate 301 is formed with a row of nozzle holes 321 to 324 to be the nozzle 11.

  At this stage, the base material 301 undergoes plastic deformation due to residual stress due to punching, and this is hardly eliminated even after polishing, so the flatness of the base material 301 becomes H3.

  Therefore, as shown in FIG. 10 (f), the base material 301 is sandwiched between the pressing members 335, and the punches 330 and 330 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. 10G, 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 (the recess rows 13A and 13B) are formed, stress is generated in the nozzle plate 1 in the direction to cancel the plastic deformation, and as a result, the flatness of the nozzle plate 1 becomes H4, and the flatness due to the initial deformation. The deformation amount is smaller than H3 (H4 <H3).

  In addition, about the order of formation of the recessed part row | line | column 13A, 13B, although there may be a time difference between driving | running | working of the punches 330 and 330, flatness can be improved more by driving | running simultaneously.

  And as shown in FIG. 9 mentioned above, the stable joining quality can be ensured by joining the nozzle plate 1 with high flatness to the flow path plate 2.

Here, the variation in the flatness of the nozzle plate 1 and the inclination of the nozzle 11 will be described with reference to FIGS. 11 and 12.
First, when the nozzle (nozzle hole) is formed by pressing as described above, the base material 301 (nozzle plate 1) undergoes plastic deformation during the nozzle hole formation process as shown in FIG. The degree of deformation is not always constant, and as a result, the flatness varies. Therefore, in the configuration in which the recess rows 13A and 13B are not provided, the flatness variation is large because the flatness is low as described above, whereas in the configuration according to the present invention in which the recess rows 13A and 13B are provided, FIG. As shown in b), the variation in flatness is also reduced.

  In addition, the nozzle 11 itself is inclined due to plastic deformation of the base material 301 (nozzle plate 1). That is, as shown in FIG. 12A, the nozzle 11 that is not inclined with respect to the droplet discharge direction 500 is ideal. Here, in the comparative example in which the recess rows 13A and 13B are not formed, since the flatness is low, the inclination of the nozzle 11 occurs in the range of the inclination amounts b1 to b2 as shown in FIG. On the other hand, in this embodiment, since the flatness is high (the flatness H4 is smaller than the flatness H3 of the comparative example), as shown in FIG.

  In this case, if the amount of inclination is uniform, it is possible to correct it with a print correction technique (for software). However, if the amount of inclination varies greatly as shown in FIG. It becomes difficult and stable print quality cannot be obtained. On the other hand, since it is possible to suppress the inclination variation as in the present embodiment, it is possible to obtain a stable print quality only by the print correction technique.

Next, a nozzle plate according to a third embodiment of the present invention and a liquid discharge head including the nozzle plate will be described with reference to FIGS. 13 is an explanatory plan view of a main part of the embodiment, and FIG. 14 is an explanatory cross-sectional view taken along line DD of FIG.
Here, the nozzle row 12 has two rows of nozzle rows 12A and 12B (both constitute one nozzle group). And the recessed part 13 of each recessed part row | line | column 13A and 13B arrange | positioned on the outer side of a nozzle row group is formed in the position corresponding to the partition 23 between the liquid chambers 22, respectively.

  That is, if the concave portion 13 is formed at a position facing the liquid chamber 22, it is trapped by the concave portion 13 when bubbles are generated, and the droplet discharge characteristics vary or fluctuate. By forming the recess 13, the risk of bubble traps can be eliminated.

  Note that a head-integrated liquid cartridge (cartridge-integrated head) can be obtained by integrating the above-described liquid discharge head 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. 15 is a schematic configuration diagram for explaining the overall configuration of the mechanism portion of the apparatus, and FIG. 16 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 discharge head according to the present invention will be described with reference to FIG. FIG. 17 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. 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 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. For example, the present invention 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 15 Nozzle row group 22 Liquid chamber 22 Liquid chamber interval wall 31 Vibration region 41 Base member 42A, 42B, 42C, 42D Piezoelectric member 42a Piezoelectric element column 233 Carriage 234a, 234b Recording head 411k, 411c, 411m, 411y Recording head

Claims (7)

In a nozzle plate having a nozzle row in which a plurality of nozzles for discharging droplets are arranged and joined to a flow path member forming a liquid chamber in which the nozzles communicate with each other,
At least two recess rows in which a plurality of recesses arranged in parallel with the nozzle row are arranged on the surface on the liquid chamber side are arranged on the opposite side across the central axis of the nozzle row. Nozzle plate to do. In a nozzle plate having a nozzle row group composed of a plurality of nozzle rows in which a plurality of nozzles for discharging droplets are arranged, and joined to a flow path member forming a liquid chamber in communication with the nozzles,
At least two recess rows in which a plurality of recesses arranged in parallel with the nozzle row are arranged on the surface on the liquid chamber side are arranged on the opposite side across the central axis of the nozzle row group. Nozzle plate.   The nozzle plate according to claim 1, wherein the concave portion is provided facing a portion other than the liquid chamber of the flow path member. In a manufacturing method of a nozzle plate having a nozzle row in which a plurality of nozzles for discharging liquid droplets are arranged and joined to a flow path member that forms a liquid chamber that communicates with the nozzles,
Forming a recess to be the nozzle on the surface of the substrate on the liquid chamber side by pressing;
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the substrate is formed, and opening the nozzle;
On the surface of the substrate on the liquid chamber side, at least two recess rows in which a plurality of recesses arranged in parallel with the nozzle row are arranged are formed by pressing on the opposite side to the central axis of the nozzle row. And a process of
A method for manufacturing a nozzle plate, wherein the steps are sequentially performed. In a manufacturing method of a nozzle plate having a nozzle row group composed of a plurality of nozzle rows in which a plurality of nozzles for discharging droplets are arranged and joined to a flow path member that forms a liquid chamber that communicates with the nozzles,
Forming a recess to be a nozzle constituting the plurality of nozzle rows on the surface of the substrate on the liquid chamber side by press working; and
Polishing the convex portion generated on the surface opposite to the surface on which the concave portion of the substrate is formed, and opening the nozzle;
On the surface of the substrate on the liquid chamber side, at least two recess rows in which a plurality of recesses arranged in parallel with the nozzle rows are arranged are pressed on the opposite side with respect to the central axis of the nozzle row group. Forming, and
A method for manufacturing a nozzle plate, wherein the steps are sequentially performed.   A liquid discharge head comprising the nozzle plate according to claim 1.   An image forming apparatus comprising the liquid discharge head according to claim 6.

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