JP2014037131A - Liquid discharge head and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen the life of a filter member without increasing a fluid resistance.SOLUTION: A first common liquid chamber member 7 and a second common liquid chamber member 5 form a common liquid chamber 10. A filter member 6 is arranged between the common liquid chamber member 7 and the second common liquid chamber member 5. The filter member 6 includes a first filter plate 61 and a second filter plate 62 that are retained one over the other with a narrower gap 63 than a nozzle diameter therebetween. The first filter plate 61 and the second filter plate 62 respectively have a plurality of through holes 61a and a plurality of through holes 62a, which are larger than the nozzle diameter, formed therein. The plurality of through holes 61a and the plurality of through holes 62a are each arranged in a two-dimensional manner in a nozzle arrangement direction and a direction perpendicular to the nozzle arrangement direction.

Description

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

  As an image forming apparatus such as a printer, a facsimile, a copying 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. Devices such as ink jet recording devices are known.

  In a liquid discharge head, there is known one in which a filter member for filtering liquid is disposed in a common liquid chamber that supplies liquid to a plurality of individual liquid chambers that communicate with nozzles that discharge liquid droplets (Patent Document 1, etc.).

  Conventionally, a plurality of metal plates forming a flow path pattern are provided with communication holes for forming flow paths, and the positions of the communication holes in the adjacent metal plates laminated and bonded are arranged so that the hole center positions are shifted. In addition, one in which each communication hole is connected by a plurality of slit-like grooves serving as a filter is known (Patent Document 2).

  In addition, it comprises a laminate composed of a plurality of plates stacked on each other, each of the plurality of plates constituting the laminate is formed with a plurality of through holes communicating with the liquid flow path, The through holes formed in adjacent plates are stacked so that they partially overlap when viewed from the stacking direction of the plates, and the part where the through holes of multiple plates are formed constitutes a filter Is known (Patent Document 3).

  Also, a structure in which a plurality of openings having a cross-sectional area smaller than the cross-sectional area of the discharge port forms a curved path, a plurality of openings having protrusions, and the interval formed between the openings and the protrusions is a discharge port. A structure having a cross-section formed smaller than the width of the plurality of openings, a plurality of openings having a cross-sectional area smaller than the cross-sectional area of the discharge port, and a column having a recess on the discharge side of the opening is concave on the anti-discharge port side There is also known a structure in which a filter is configured with a structure provided with a cross section and a cross-section in which a plurality of protrusions are provided in the width direction at intervals narrower than the width of the discharge port (Patent Document 4).

JP 2009-0669904 A JP 2001-328264 A JP 2008-018662 A Japanese Patent Application Laid-Open No. 06-312506

  However, in the configuration disclosed in Patent Document 2, since the groove is used as a filter, there is a problem that clogging is likely to occur and the fluid resistance is extremely increased.

  Moreover, in the structure currently disclosed by patent document 4, since the height of the column part which forms an opening part is controlled by a nozzle diameter, there exists a subject that the fluid resistance in a flow path becomes large. In this case, if the height of the column portion is increased in order to reduce the fluid resistance, the shape of the opening portion becomes a rectangular shape, which causes a problem that the trapping property of the rectangular foreign matter is deteriorated.

  The present invention has been made in view of the above problems, and an object of the present invention is to extend the life of a filter member without causing an increase in fluid resistance.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A plurality of nozzles for discharging droplets;
A plurality of individual liquid chambers through which the nozzle communicates;
A common liquid chamber for supplying a liquid to the plurality of individual liquid chambers,
A filter member for filtering the liquid is provided in the common liquid chamber,
The filter member has at least two filter plates held with a gap narrower than the nozzle diameter.
A plurality of through holes larger than the nozzle diameter are formed in the filter plate,
The plurality of through holes are arranged in a two-dimensional manner on the filter plate.

  According to the present invention, the lifetime of the filter member can be extended without increasing the fluid resistance.

FIG. 3 is an external perspective view illustrating an example of a liquid discharge head according to the present invention. It is sectional explanatory drawing in alignment with the direction orthogonal to the nozzle arrangement direction of the head. It is sectional explanatory drawing along the nozzle arrangement direction of the head. It is a plane explanatory view of the filter member concerning a 1st embodiment of the present invention. FIG. 5 is a cross-sectional explanatory diagram and an enlarged explanatory diagram of a nozzle taken along line AA of FIG. 4 of the filter member. It is a plane explanatory view of the 1st filter board and the 2nd filter board. It is a plane explanatory view of a filter member concerning a 2nd embodiment of the present invention. It is a plane explanatory view of a filter member concerning a 3rd embodiment of the present invention. It is a plane explanatory view of a filter member concerning a 4th embodiment of the present invention. It is a plane explanatory drawing similarly. It is a plane explanatory view of a filter member concerning a 5th embodiment of the present invention. It is a plane explanatory view of a filter member concerning a 6th embodiment of the present invention. It is a plane explanatory view of a filter member concerning a 7th embodiment of the present invention. It is a plane explanatory view of a filter member concerning an 8th embodiment of the present invention. It is an expanded sectional explanatory view which follows the BB line of FIG. It is sectional explanatory drawing with which it uses for description of an example of the method of manufacturing the filter board of the said 8th Embodiment. Similarly, it is a cross-sectional explanatory view for explaining another example of the method for producing the filter plate of the eighth embodiment. It is sectional explanatory drawing with which it uses for description of the relationship between the plate | board thickness of a filter board in the case of performing an etching process, and the hole diameter of a through hole. It is a section explanatory view of a filter member concerning a 9th embodiment of the present invention. It is a section explanatory view of a filter member concerning a 10th embodiment of the present invention. It is the plane explanatory view seen from the 1st filter board side of the filter member. It is the plane explanatory view seen from the 1st filter board side of the filter member concerning an 11th embodiment of the present invention. It is plane explanatory drawing seen from the 1st filter board side of the filter member which concerns on 12th Embodiment of this invention. FIG. 17 is a cross-sectional explanatory view similar to FIG. 15 of a filter member according to a thirteenth embodiment of the present invention. FIG. 16 is a cross-sectional explanatory view similar to FIG. 15 of a filter member according to a fourteenth embodiment of the present invention. It is a side explanatory view of a mechanism portion showing an example of an image forming apparatus according to the present invention. It is principal part plane explanatory drawing of the mechanism part.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An example of a liquid discharge head according to the present invention will be described with reference to FIGS. FIG. 1 is an external perspective view of the head, FIG. 2 is a cross-sectional view along the direction perpendicular to the nozzle arrangement direction of the head, and FIG. 3 is a cross-sectional view along the nozzle arrangement direction of the head.

  In this liquid discharge head, a nozzle plate 2, a flow path plate 3 that is a flow path member, and a vibration plate member 4 are joined together with an adhesive.

  In the nozzle plate 2, a plurality of nozzles 20 for discharging droplets are arranged in four rows in a staggered manner. The nozzle plate 2 is formed with a nozzle 20 by press working using, for example, stainless steel (here, SUS316).

  The flow path plate 3 forms a pressure chamber 21 that is an individual liquid chamber communicating with the nozzle 20. The flow path plate 3 is formed by press working using, for example, stainless steel (here, SUS304).

  The diaphragm member 4 forms a part of the wall surface of the pressure chamber 21 as a displaceable vibration region 4a. In addition, a liquid supply path 22 is formed in the diaphragm member 4 so as to face a downstream common liquid chamber 25 described later and through the downstream common liquid chamber 25 and each pressure chamber 21. The diaphragm member 4 is formed by Ni electroforming.

  The second common liquid chamber member 5, the filter member 6, and the first common liquid chamber member 7 that also serves as the frame of the head are sequentially laminated on the side opposite to the pressure chamber 21 of the diaphragm member 4 and bonded with an adhesive. doing.

  A common liquid chamber 10 communicating with each pressure chamber 21 is formed by the first common liquid chamber member 7 and the second common liquid chamber member 5. The common liquid chamber 10 includes an upstream common liquid chamber 26 on the upstream side of the filter member 6 and a downstream common liquid chamber 25 on the downstream side. The details of the filter member 6 will be described later.

  The filter member 6 collects (captures) foreign matter from the liquid flowing from the upstream common liquid chamber 26 to the downstream common liquid chamber 25.

  In the present embodiment, the first common liquid chamber member 7 forms the upstream common liquid chamber 26, and discharges the liquid to the outside with a liquid supply port portion 37 for supplying liquid from the outside to both ends in the nozzle arrangement direction. A liquid discharge port portion 38 is provided.

  A piezoelectric actuator 8 is disposed on the vibration region 4 a of the diaphragm member 4 on the side opposite to the pressure chamber 21. The piezoelectric actuator 8 joins two piezoelectric members 32 formed by alternately forming columnar piezoelectric elements (piezoelectric columns) 32A and 32B, for example, at half the nozzle pitch, to one base member 33 in accordance with two nozzle rows. doing. In addition, since the nozzle row of this embodiment is four rows, the two piezoelectric actuators 8 are arrange | positioned.

  Each piezoelectric column 32 </ b> A of the piezoelectric member 32 is joined to the vibration region 4 a of the diaphragm member 4, and a drive signal is given via the flexible wiring member 34 from a driving IC 81 (see FIG. 3) provided in the flexible wiring member 34. . The piezoelectric column 32B that is not joined to the vibration region 4a of the diaphragm member 4 is joined to a position corresponding to the pressure chamber spacing wall 21A.

  In this liquid discharge head, the vibration region 4 a of the vibration plate member 4 is displaced by driving the piezoelectric actuator 8, the liquid in the pressure chamber 21 is pressurized, and a droplet is discharged from the nozzle 20.

  Next, the filter member according to the first embodiment of the present invention will be described with reference to FIGS. 4 is a plan view of the filter member, FIG. 5 is a cross-sectional view of the filter member taken along line AA in FIG. 4 and an enlarged view of the nozzle, and FIG. 6 is a plan view of the first filter plate and the second filter plate. It is explanatory drawing.

  The filter member 6 has a first filter plate 61 and a second filter plate 62. The first filter plate 61 is formed with a plurality of through holes 61a having a hole diameter Df1 larger than the diameter (hereinafter referred to as “nozzle diameter”) Dn of the nozzle 20. Similarly, a plurality of through holes 62a having a hole diameter Df2 larger than the nozzle diameter Dn are formed in the second filter plate 62.

  Here, the through holes 61a and 62a of the first filter plate 61 and the second filter plate 62 are two-dimensionally arranged. In this example, the nozzles are arranged in two directions: a nozzle arrangement direction and a direction orthogonal to the nozzle arrangement direction.

  The hole diameter Df1 of the through hole 61a of the first filter plate 61 and the hole diameter Df2 of the through hole 62a of the second filter plate 62 may be the same or different.

  The first filter plate 61 and the second filter plate 62 are held in a stacked manner with a gap 63 therebetween. Here, the height of the gap 63 in the overlapping direction (hereinafter referred to as “gap width”) Gh is narrower than the nozzle diameter Dn (Dn> Gh).

  Here, the plurality of through holes 61a of the first filter plate 61 and the plurality of through holes 62a of the second filter plate 62 do not overlap with each other in the overlapping direction. Formed in position.

  In the present embodiment, as shown in FIG. 4, the plurality of through holes 61 a of the first filter plate 61 are arranged adjacent to each other in one direction (here, the short direction), In the other direction (herein, the longitudinal direction) orthogonal to the direction, at least one through hole is spaced apart. Similarly, the plurality of through holes 62a of the second filter plate 62 are arranged adjacent to each other in the short side direction and at least one through hole in the long side direction.

  Since the through hole 61a of the first filter plate 61 and the through hole 62a of the second filter plate 62 are arranged at positions that do not overlap in the overlapping direction, the through hole of the first filter plate 61 is arranged in the longitudinal direction of the filter member 6. 61a and the through holes 62a of the second filter plate 62 are alternately arranged. In addition, although it is set as the relationship arrange | positioned alternately in one direction here, it can also be set as the relationship arrange | positioned alternately in the other direction.

  With this configuration, when the liquid flows from the upstream common liquid chamber 26 to the downstream common liquid chamber 25, the liquid passes through the first filter plate 61 as shown by an arrow 301 in FIG. 61a enters the gap 63 between the first filter plate 61 and the second filter plate 62, and flows out from the through hole 62a of the second filter plate 62 through the gap 63.

  At this time, as shown in FIG. 5, the foreign material 300 larger than the nozzle diameter Dn contained in the liquid passes through the through hole 61 a of the first filter plate 61, but the first filter plate 61 and the second filter plate 62 Since the gap width Gh is narrower than the nozzle diameter Dn, the foreign matter 300 cannot pass through the gap 63 and enters the downstream common liquid chamber 25 from the through hole 62a of the second filter plate 62. There is no invasion.

  That is, the filter member 6 has a filter function in the gap 63 between the first filter plate 61 and the second filter plate 62.

  Thus, by providing a filter function in the gap between at least two filter plates, the entire gap between the filter plates becomes a flow path, so that clogging is less likely to occur, and the fluid resistance is also smaller than the groove. The lifetime of

  In other words, as in the past, when the groove formed in the plate has a filter function, the depth of the groove is regulated by the thickness of the plate and can be used to obtain the required groove depth. Will be limited in thickness.

  On the other hand, the thickness of the filter plate is not restricted at all by obtaining the necessary dimensions as a filter by the gap between the two filter plates as in this embodiment. For example, it is also possible to configure the plate with a thinner plate than the necessary gap, and the degree of freedom in configuration increases.

  Further, when the groove formed in the plate is provided with a filter function and one liquid inlet is arranged for each groove, the groove is filtered by foreign matter clogging at the groove inlet. As a result, clogging is likely to occur.

  On the other hand, by providing a filter function in the gap between two filter plates as in this embodiment, by forming a plurality of through holes having a diameter larger than the nozzle diameter in the two filter plates, There are a plurality of through-holes into which the liquid connected to the gap flows, and since there are no side walls like grooves, the direction of the liquid flow in the gap is less spatially limited.

  Thereby, even if a large foreign matter is captured by the gap, the flow of the liquid is less likely to be blocked, clogging is less likely to occur, and the life of the filter is prolonged.

  In addition, when the groove formed in the plate is provided with a filter function and the size of the foreign matter to be captured is defined by the groove depth, the liquid needs to flow through the groove portion relatively long with respect to the groove depth. In addition, the fluid resistance to the liquid becomes very large, and there is a possibility that the liquid supply accompanying the droplet ejection may not be in time.

  On the other hand, by providing a filter function in the gap between two filter plates as in this embodiment, by forming a plurality of through holes having a diameter larger than the nozzle diameter in the two filter plates, As described above, there is less spatial restriction in the liquid flow direction in the gap, and the distance from the inlet to the outlet is shorter than the groove, and the distance is equal to or shorter than the gap. be able to. As a result, even if the gap is narrowed so that smaller foreign substances can be collected, the fluid resistance does not increase and the flow of the liquid is not hindered. Can be driven at high speed.

  Furthermore, as in other conventional filter members, in the configuration that forms an opening of a diameter (size) necessary to collect foreign matter by shifting and overlapping plates with large holes, In order to obtain an opening having a required diameter, it is necessary to extremely increase the size of the holes and the accuracy of the arrangement, and it is also necessary that the assembly accuracy be equal to or less than the opening.

  On the other hand, as in this embodiment, a filter function is provided in the gap between the two filter plates, and the two filter plates are not overlapped by forming a plurality of through holes having a diameter larger than the nozzle diameter. By arranging in this way, it is possible to regulate the size of foreign matter that can be collected by managing the gap between the two filter plates, and even if there is a slight difference in the size and arrangement of the through holes, there is no problem. The function of can be demonstrated. Further, since the through hole can be made larger than the nozzle diameter, the processing accuracy can be lowered, so that the yield in manufacturing can be improved.

  Next, a filter member according to a second embodiment of the present invention will be described with reference to FIG. FIG. 7 is an explanatory plan view of the filter member.

  In the present embodiment, the plurality of through holes 61a of the first filter plate 61 and the through holes 62a of the second filter plate 62 are each formed in a staggered arrangement.

  By configuring in this way, the arrangement of the through holes 61a and 62a of the first and second filter plates 61 and 62 is overlapped more than the center distance La between adjacent through holes formed in the same filter plate. The distance Lb to the through hole formed in another filter plate adjacent in the direction becomes shorter.

  That is, for example, it is adjacent in the overlapping direction rather than the center distance La to the adjacent other through hole 61a formed in the first filter plate 61 which is the same filter plate as one through hole 61a of the first filter plate 61. The distance Lb to the through hole 62a formed in the second filter plate 62, which is another filter plate, is shorter.

  Thereby, the through holes on the same filter plate can be separated, and the liquid passing through the filter member 6 in the thickness direction (stacking direction) can easily flow in the thickness direction.

  Next, a filter member according to a third embodiment of the present invention will be described with reference to FIG. FIG. 8 is an explanatory plan view of the filter member.

  In the present embodiment, the plurality of through holes 61a of the first filter plate 61 and the through holes 62a of the second filter plate 62 are each formed in a matrix with an interval of approximately one through hole.

  Even if comprised in this way, the effect similar to the said 2nd Embodiment can be acquired.

  Next, the filter member which concerns on 4th Embodiment of this invention is demonstrated with reference to FIG.9 and FIG.10. FIG. 9 is an explanatory side view of the filter member, and FIG. 10 is an explanatory plan view of the same. In FIG. 10, in order to make the spacer portion (member) easy to understand, it is not a cross section but is hatched (hereinafter the same applies).

  In the present embodiment, a spacer member 64 is disposed between the first filter plate 61 and the second filter plate 62, and a gap narrower than the nozzle diameter is provided between the first filter plate 61 and the second filter plate 62. Form and hold.

  Here, the spacer member 64 is arranged in a frame shape around the filter member 6.

  The material of the spacer member 64 is preferably a material that does not elute with respect to the liquid. In addition, since the gap 63 is defined, it has sufficient rigidity, and the first filter plate 61 and the second filter plate 62 in which the through holes 61a and 62a are formed are manufactured by etching or electroforming. These are metal materials, and considering the bonding properties with these, it is preferable to be a metal plate. In particular, when water-based ink is used as the liquid, stainless steel is preferable from the viewpoint of rust prevention, and examples thereof include SUS316, SUS304, and SUS303.

  Thus, by defining the gap between the first filter plate 61 and the second filter plate 62 with the spacer member 64, the required gap width Gh can be easily obtained.

  Next, a filter member according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 11 is an explanatory plan view of the filter member.

  In the present embodiment, as the spacer member 64, a frame-like portion 64a and a bridge portion 64b that bridges the frame-like portion 64a are provided, and the filter member 6 is partitioned into a plurality of (here, three) regions by the bridge portion 64b. doing.

  Since it comprised in this way, the bridge | crosslinking part 64b of the spacer member 64 becomes a reinforcement member, and it can reduce that the 1st filter board 61 and the 2nd filter board 62 deform | transform, and the gap width Gh of a clearance gap fluctuates.

  Further, in the present embodiment, the bridging portion 64 b of the spacer member 64 is disposed at a position that does not overlap with the through holes 61 a and 62 a of the first filter plate 61 and the second filter plate 62. In other words, the through holes 61 a and 62 a of the first filter plate 61 and the second filter plate 62 are formed at positions that do not face the bridging portion 64 b of the spacer member 64.

  Accordingly, in the partitioned area, the flow of the liquid is not hindered by the bridging portion 64b functioning as a reinforcement.

  Next, a filter member according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 12 is an explanatory plan view of the filter member.

  Also in the present embodiment, as in the fifth embodiment, the spacer member 64 is provided with a frame-like portion 64a and a bridging portion 64b that bridges the frame-like portion 64a, and a plurality of filter members 6 (here) Then, it is divided into two areas.

  In this case, the bridging portion 64 b of the spacer member 64 is disposed at a position overlapping the through holes 61 a and 62 a of the first filter plate 61 and the second filter plate 62.

  By so doing, the formation position accuracy of the bridging portion 64b of the spacer member 64 becomes gentler than that of the fifth embodiment.

  Next, a filter member according to a seventh embodiment of the present invention will be described with reference to FIG. FIG. 13 is an explanatory plan view of the filter member.

  In the present embodiment, the bridging portion 64 b of the spacer member 64 is disposed at a position that overlaps each row of the through holes 61 a and 62 a of the first filter plate 61 and the second filter plate 62.

  Next, a filter member according to an eighth embodiment of the present invention will be described with reference to FIGS. FIG. 14 is an explanatory plan view of the filter member, and FIG. 15 is an enlarged sectional explanatory view taken along the line BB of FIG.

  In the present embodiment, a spacer portion (gap forming means) is formed in a surface of the first filter plate 61 that faces the second filter plate 62 and in a region that does not form the through hole 61a and does not face the through hole 62a. The protrusion 65 is integrally formed (the first filter plate 61 and the protrusion 65 are collectively referred to as “filter plate 60”). Here, the protrusion 65 is integrally formed on the first filter plate 61, but the protrusion 65 may be integrally formed on the second filter plate 62 side.

  As described above, when the spacer portion is provided separately on one of the opposing surfaces of the two opposing filter plates (here, the first filter plate 61 and the second filter plate 62), the spacer portion is a separate member. This eliminates the need for a joining process between the spacer member and the filter plate, which reduces the number of manufacturing steps.

  It should be noted that the embodiment relating to the arrangement of the filter holes described in the first to eighth embodiments may be combined with the embodiment using the space member.

  Next, an example of a method for manufacturing the filter plate of the eighth embodiment will be described with reference to FIG. FIG. 16 is an explanatory cross-sectional view for explaining the same.

  As shown in FIG. 16A, a resist pattern 402 corresponding to a portion to be a through hole is formed on the electroformed support substrate 401. And as shown in FIG.16 (b), the 1st layer 403 used as the 1st filter board 61 which performs electroforming on the electroforming support substrate 401 and forms a through-hole is formed.

  Thereafter, as shown in FIG. 16C, a resist pattern 404 corresponding to a portion that becomes a gap is formed on the first layer 403. And as shown in FIG.16 (d), the 2nd layer 405 which forms the projection part 65 used as a spacer part by electroforming on the 1st layer 403 is integrally formed.

  Next, as shown in FIG. 16E, the laminated electroformed film of the first layer 403 and the second layer 405 is peeled from the second electroformed support substrate 401, and the resist patterns 402 and 404 are removed.

  Thereby, the filter plate 60 including the first layer 403 to be the first filter plate 61 in which the through hole 61a is formed and the second layer 405 to form the spacer portion (projection portion) 65 is obtained.

  As described above, when the spacer portion is formed by electroforming, it can be easily formed by adopting a two-layer structure, and its height can be controlled by the processing time or the like, so that it is easily the same. Can be formed.

  Next, another example of the filter plate manufacturing method of the eighth embodiment will be described with reference to FIG. FIG. 17 is a cross-sectional explanatory view for explaining the same.

  As shown in FIG. 17A, a resist pattern 502 is formed in a region other than the through hole on one surface of a substrate 501 serving as a filter plate, and a resist pattern 504 corresponding to a region other than the spacer portion is formed on the other surface. Form.

  And as shown in FIG.17 (b), it etches from both surfaces of the board | substrate 501, and the part corresponding to a through-hole and a clearance gap is removed.

  Thereafter, the resist patterns 502 and 504 are removed from the substrate 501 as shown in FIG.

  Thereby, the through-hole 61a is formed and the 1st filter board 61 which has the spacer part 65 is obtained.

  In the description of these manufacturing methods, the first filter plate is described, but the second filter plate can be manufactured in the same manner.

  Here, the relationship between the plate thickness of the filter plate and the hole diameter of the through hole when etching is performed will be described with reference to FIG. FIG. 18 is a cross-sectional explanatory view for explaining the same.

  In this example, resist patterns 502 and 502 for forming through holes are formed on both surfaces of the substrate 501, and through holes 61a are formed by etching.

  Here, FIGS. 18A1 and 18A2 illustrate the case where the hole diameter Df of the through hole 61a is larger than the plate thickness t of the first filter plate 61. FIGS. This is a case where the hole diameter Df of the through hole 61a is smaller than the plate thickness t of the filter plate 61.

  As shown in FIG. 18, when the through holes 61a are formed by etching from both surfaces of the substrate 501, undercut (side etching) always occurs in the depth direction (thickness direction) in the etching process.

  Therefore, in the etching process, a step always occurs between the surface part and the center part in the plate thickness direction, and even in the case of double-sided etching, a difference of 10 to 20% of the plate thickness occurs, and the resist pattern opening diameter Dr and the processed hole It does not match the diameter (required hole diameter) Df.

  Here, as shown in FIGS. 18A1 and 18A2, when the hole diameter Df of the through hole 61a is larger than the plate thickness t, the hole diameter Df after processing and the opening diameter Dr of the resist pattern The ratio becomes smaller, and the hole diameter accuracy can be easily managed.

  On the other hand, as shown in FIGS. 18B1 and 18B2, when the hole diameter of the through hole 61a is larger than the plate thickness t, the hole diameter Df after processing and the opening diameter Dr of the resist pattern Therefore, it becomes difficult to manage the accuracy of the hole diameter, and it becomes difficult to maintain the accuracy of the hole diameter Df by etching.

  Therefore, when the through hole of the filter plate is formed by etching, it is preferable that the diameter of the through hole is equal to or greater than the plate thickness of the filter plate. Here, the first filter plate is described, but the same applies to the second filter plate.

  Next, a filter member according to a ninth embodiment of the present invention will be described with reference to FIG. FIG. 19 is an explanatory sectional view of the filter member.

  In the present embodiment, the filter member 6 has three filter plates 161 to 162 that are held in layers with a gap narrower than the nozzle diameter. The filter member 6 includes a first filter plate 161, a second filter plate 162, and a third filter plate 163 from the upstream side in the liquid flow direction.

  The first filter plate 161 has a plurality of through holes 161a having a hole diameter Df1 larger than the nozzle diameter Dn. Similarly, a plurality of through holes 162a having a hole diameter Df2 larger than the nozzle diameter Dn are formed in the second filter plate 162. Similarly, a plurality of through holes 163a having a hole diameter Df3 larger than the nozzle diameter Dn are formed in the third filter plate 163.

  The hole diameter Df1 of the through hole 161a of the first filter plate 161, the hole diameter Df2 of the through hole 162a of the second filter plate 162, and the hole diameter Df3 of the through hole 163a of the second filter plate 163 are the same (Df1 = Df2 = Df3). However, the hole diameters Df1, Df2, and Df3 may be different.

  The first filter plate 161 and the second filter plate 162 are held in an overlapping manner with a gap 165, and the second filter plate 162 and the third filter plate 163 are held with a gap 166, respectively. Yes.

  Here, the gap width Ghu of the gap 165 and the gap width Ghd of the gap 166 are both narrower than the nozzle diameter Dn (Dn> Ghu, Dn> Ghd). The gap width Ghd of the gap 166 is narrower (Ghu> Ghd) than the gap width Ghu of the gap 165. That is, it arrange | positions so that the space | interval of two filter plates which oppose may become small, so that it goes to the downstream of the flow of a liquid.

  Here, the plurality of through holes 161a of the first filter plate 161 and the plurality of through holes 162a of the second filter plate 162 do not overlap with each other in the overlapping direction. Formed in position. Similarly, the plurality of through holes 162a of the second filter plate 162 and the plurality of through holes 163a of the third filter plate 163 do not overlap with each other in the overlapping direction in the filter plates 162 and 163. Formed in position.

  With this configuration, when the liquid flows from the upstream common liquid chamber 26 to the downstream common liquid chamber 25, the liquid flows through the first through hole 161 a of the first filter plate 161 as indicated by an arrow 301 in FIG. 19. The gap 165 between the first filter plate 161 and the second filter plate 162 enters.

  Then, the gap 165 passes through the through hole 162 a of the second filter plate 162 and enters the gap 166 between the second filter plate 162 and the third filter plate 163. Thereafter, the gas flows out from the gap 166 through the through hole 163a of the third filter plate 163.

  At this time, the foreign matter 300A, 300B larger than the nozzle diameter Dn contained in the liquid passes through the through hole 161a of the first filter plate 161 and enters the gap 165 between the first filter plate 161 and the second filter plate 162. enter.

  Here, since the gap 165 between the first filter plate 161 and the second filter plate 162 has a gap width Ghu smaller than the nozzle diameter Dn, the foreign matter 300A larger than the gap width Ghu passes through the gap 165. Cannot be captured.

  On the other hand, the foreign matter 300B smaller than the gap width Ghu can pass through the gap 165, and therefore enters the gap 165 between the second filter plate 162 and the third filter plate 163 from the through hole 162a of the second filter plate 162. .

  Here, since the gap width Ghd is narrower than the nozzle diameter Dn, the foreign material 300B larger than the gap width Ghd cannot pass through the gap 166 and is captured.

  In this way, foreign matter is prevented from entering the downstream common liquid chamber 25.

  That is, the filter member 6 has a filter function in the gap 165 between the first filter plate 161 and the second filter plate 162 and the gap 166 between the second filter plate 162 and the third filter plate 163, respectively. Is.

  In the liquid flow direction, the gap between the filter plates is reduced toward the downstream side so that fine foreign matters can be collected.

  Thereby, coarse foreign matters can be captured on the upstream side, and fine foreign matters can be captured on the downstream side. Therefore, if the amount of foreign matter collected is the same until the ink supply does not function even if it is collected in each layer, it becomes possible to increase the allowable amount by stacking the layers. It is possible to increase the amount of foreign matter collected until the filter is clogged, and the life of the filter can be extended.

  Next, the filter member which concerns on 10th Embodiment of this invention is demonstrated with reference to FIG.20 and FIG.21. FIG. 20 is an explanatory cross-sectional view of the filter member, and FIG. 21 is an explanatory plan view of the filter member as viewed from the first filter plate side.

  In the present embodiment, the through hole 161a of the first filter plate 161 and the through hole 162a of the second filter plate 162 are partially overlapped (the through holes 161a and 162a are formed at the overlapping positions). .

  The gap width Ghu of the gap 165 between the first filter plate 161 and the second filter plate 162 and the gap width Ghd of the gap 166 between the second filter plate 162 and the third filter plate 163 may be the same. Alternatively, Ghu> Ghd may be used as in the ninth embodiment.

  For example, as shown in claim 2, on the upstream side, it may be arranged so that holes can overlap between adjacent plates.

Thus, for example, when the through hole 161a of the first filter plate 161 and the through hole 162a of the second filter plate 162 are partially overlapped with each other, the gap 165 and the overlap width up to the square root of the square sum of the overlap width are obtained. A foreign object of a size can pass through. That is, the size Dfu that can be collected in the gap 165 is Dfu = √ (X ² + Ghu ² ), where X is the overlap width of the through holes 161a and 162a, and Gap is the gap width Ghu of the gap 165.

  Therefore, the size of the foreign matter that can be collected by the filter formed by the gap 165 between the first filter plate 161 and the second filter plate 162 is larger than when there is no overlap, and the foreign matter smaller than that is gap 165. And is collected in a filter capable of collecting fine foreign matters on the downstream side.

  As a result, the total amount of foreign matters that can be collected by the filter plates arranged in series can be increased, so that it is possible to prevent functional degradation due to clogging.

  Next, a filter member according to an eleventh embodiment of the present invention will be described with reference to FIG. FIG. 22 is an explanatory plan view of the same filter member as viewed from the first filter plate side.

  In the tenth embodiment, the through holes 161a of the first filter plate 161 and the through holes 162a of the second filter plate 162 have the same size, and overlap is formed in the arrangement positional relationship.

  In contrast, in the present embodiment, the size (opening area) of the through hole 161a of the first filter plate 161 on the upstream side is made larger than the size of the through hole 162a of the second filter plate 162, and the through hole 161a. And the through hole 162a are overlapped.

  Next, a filter member according to a twelfth embodiment of the present invention will be described with reference to FIG. FIG. 23 is an explanatory plan view of the filter member as viewed from the first filter plate side.

  In the present embodiment, the number of the through holes 161a of the first filter plate 161 on the upstream side is made larger than the number of the through holes 162a of the second filter plate 162 to form an overlap of the through holes 161a and the through holes 162a. Yes.

  As in these eleventh and second embodiments, the size of the through hole of the upstream filter plate of the two filter plates facing each other is increased, or the number is increased, so that per unit area The amount of foreign matter that can be collected can be increased, and the amount of foreign matter that can be collected can be increased as compared to the case of shifting the position with the same size of the through hole as in the tenth embodiment.

  The filter member according to the present invention is configured to collect foreign matter at the outer peripheral portion of the through hole, and the amount of foreign matter that can be repaired can be increased as the outer peripheral portion of the through hole increases per unit area.

  Next, a filter member according to a thirteenth embodiment of the present invention will be described with reference to FIG. FIG. 24 is a cross-sectional explanatory view similar to FIG. 15 of the filter member.

  In the present embodiment, a spacer portion (gap forming means) is provided in a region of the first filter plate 161 that faces the second filter plate 162 and that does not form the through hole 161a and does not face the through hole 162a. The protrusion 167 is integrally formed. Further, a protrusion 168 serving as a spacer portion (gap forming means) is formed on a surface of the third filter plate 163 facing the second filter plate 162 and in a region where the through hole 163a is not formed and not opposed to the through hole 162a. Are integrally formed.

  Next, a filter member according to a fourteenth embodiment of the present invention will be described with reference to FIG. FIG. 25 is a cross-sectional explanatory view similar to FIG. 15 of the filter member.

  In the present embodiment, spacers are provided on both sides of the second filter plate 162 sandwiched between the first filter plate 161 and the third filter plate 163 in regions where the through holes 162a are not formed and not opposed to the through holes 161a. A protrusion 169A to be a portion (gap forming means) is integrally formed, and a protrusion 169B to be a spacer portion (gap forming means) is integrally formed in a region where the through hole 162a is not formed and is not opposed to the through hole 163a. Yes.

  Thereby, the number of filter plates forming the spacer portion is smaller than that in the thirteenth embodiment.

  Next, an example of the image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 26 is an explanatory side view of the mechanism portion of the apparatus, and FIG. 27 is an explanatory plan view of an essential part of the mechanism portion.

  This image forming apparatus is a serial type image forming apparatus. The 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, and the direction of the arrow is indicated by a main scanning motor (not shown) via a timing belt. Move and scan in the carriage main scanning direction.

  The carriage 233 includes a plurality of recording heads 234 including the liquid ejection head according to the present invention for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). Nozzle rows composed of nozzles are arranged in the sub-scanning direction orthogonal to the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

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

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the 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 the 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 member 245, It is sandwiched between the counter roller 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 pressure roller 249, and the conveying direction is changed by about 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, it is possible to reduce clogging of the filter member (remove accumulated foreign matter) and perform stable liquid supply. And a high quality image can be stably formed.

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

  The “image forming apparatus” means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “Formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply causing a droplet to land on the medium). ) Also means.

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

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

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

2 Nozzle plate 3 Flow channel plate 4 Vibration plate member 5 Second common liquid chamber member 6 Filter member 7 First common liquid chamber member 8 Piezoelectric actuator 10 Common liquid chamber 20 Nozzle 21 Pressure chamber (individual liquid chamber)
61 First filter plate 62 Second filter plate 63 Clearance 64 Spacer member (spacer part)
65 Protrusion (spacer)
233 Carriage 234a, 234b Recording head

Claims (13)

A plurality of nozzles for discharging droplets;
A plurality of individual liquid chambers through which the nozzle communicates;
A common liquid chamber for supplying a liquid to the plurality of individual liquid chambers,
A filter member for filtering the liquid is provided in the common liquid chamber,
The filter member has at least two filter plates held with a gap narrower than the nozzle diameter.
A plurality of through holes larger than the nozzle diameter are formed in the filter plate,
The liquid ejection head, wherein the plurality of through holes are arranged two-dimensionally on the filter plate.   2. The liquid ejection head according to claim 1, wherein the plurality of through holes of the two filter plates are formed at positions where the through holes of the filter plates do not overlap in the overlapping direction.   The arrangement of the plurality of through holes in the filter plate is formed in the other filter plate adjacent in the overlapping direction, rather than the center-to-center distance between adjacent through holes formed in the same filter plate. The liquid discharge head according to claim 1, wherein a distance to the through hole is shorter.   4. The liquid discharge head according to claim 1, wherein the gap is formed through a spacer portion sandwiched between the two filter plates.   5. The liquid ejection head according to claim 4, wherein the spacer portion is disposed at a position that divides the filter plate into a plurality of regions when viewed from the overlapping direction of the two filter plates.   The liquid ejection head according to claim 5, wherein the spacer portion and the through hole of the filter plate do not overlap in the overlapping direction.   The liquid ejection head according to claim 4, wherein the spacer portion is formed integrally with at least one of the filter plates. A plurality of nozzles for discharging droplets;
A plurality of individual liquid chambers through which the nozzle communicates;
A common liquid chamber for supplying a liquid to the plurality of individual liquid chambers,
A filter member for filtering the liquid is provided in the common liquid chamber,
The filter member has at least three filter plates that are stacked and held with a gap narrower than the nozzle diameter,
A plurality of through holes larger than the nozzle diameter are formed in the filter plate,
A liquid discharge head, wherein a distance between two opposing filter plates is reduced toward a downstream side of a liquid flow. A plurality of nozzles for discharging droplets;
A plurality of individual liquid chambers through which the nozzle communicates;
A common liquid chamber for supplying a liquid to the plurality of individual liquid chambers,
A filter member for filtering the liquid is provided in the common liquid chamber,
The filter member has at least three filter plates that are stacked and held with a gap narrower than the nozzle diameter,
A plurality of through holes larger than the nozzle diameter are formed in the filter plate,
The liquid discharge head according to claim 1, wherein at least two of the filter plates facing each other are arranged in a state where a part of the through hole overlaps.   Of the two filter plates arranged with the through holes overlapping, the opening area of the through hole formed in the filter plate arranged on the upstream side in the liquid flow direction is arranged on the downstream side. The liquid discharge head according to claim 9, wherein the liquid discharge head is larger than an opening area of the through hole formed in the filter plate.   Of the two filter plates arranged in a state where the through holes overlap, the number of the through holes formed in the filter plate arranged on the upstream side in the liquid flow direction is arranged on the downstream side. The liquid discharge head according to claim 9, wherein the number of the through holes formed in the filter plate is larger than the number of the through holes.   12. The liquid ejection according to claim 8, wherein spacer portions are formed on both surfaces of the filter plate disposed between the two filter plates so as to form a gap with the opposing filter plate. head.   An image forming apparatus comprising the liquid discharge head according to claim 1.

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