JP6273865B2 - Nozzle plate manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a nozzle plate of a liquid ejection device.

  Patent Document 1 discloses a liquid ejection device (liquid ejection head) for image recording. The liquid ejecting apparatus includes a nozzle plate in which a plurality of nozzles are formed, a flow path unit in which a plurality of ink chambers communicating with the plurality of nozzles are formed, and a plurality of pressures that act on the ink in the plurality of ink chambers. It has a piezoelectric element. When the piezoelectric element is driven by a drive signal supplied from the outside, pressure is applied to the ink chamber, and ink is ejected from the nozzle communicating with the ink chamber.

  By the way, in the liquid ejecting apparatus as described above, the shape and position of each nozzle formed on the nozzle plate have a great influence on the size and landing position of the dots formed on the recording medium, and consequently the image quality of the recorded image. . Therefore, conventionally, as a method for forming a plurality of nozzles of the nozzle plate, laser processing capable of high-precision processing has been widely adopted. In general laser processing, a nozzle forming member such as a light-shielding mask having a large number of holes is installed on a substrate serving as a nozzle plate, and laser light is emitted from the laser irradiation device to the nozzle forming member. Irradiate. And many nozzles are formed in the said base material at once with the laser beam which passed the member for nozzle formation.

  Patent Document 1 describes a problem that the shape or the like of the nozzles is different among a plurality of nozzles due to variations or variations in beam characteristics in the laser light. In order to suppress this, in Patent Document 1, each nozzle is formed by multiple times of laser light irradiation.

JP 2009-61775 A

  When there are a large number of nozzles to be formed on the substrate, all of the nozzles may not be formed at a time by one-time laser light irradiation from the laser irradiation apparatus. In this case, it is necessary to irradiate the base material for forming a plurality of nozzles a plurality of times.

  Here, it is only necessary to always irradiate laser light having the same intensity (characteristics) from the laser irradiation device in a plurality of laser irradiation steps, but actually, the intensity of the laser light may change with time. In that case, since the intensity of the laser beam is different in different irradiation processes, the shape of the nozzle (particularly, the nozzle diameter) is different between the nozzles formed in the respective irradiation processes. In addition, when forming the nozzle by dividing the laser light irradiation into a plurality of times, a light shielding mask or the like is used to change the region of the substrate on which the nozzle is formed before the next irradiation step after the previous irradiation step. It is necessary to move or rotate the nozzle forming member relative to the substrate. Due to errors in movement and rotation at that time, the nozzle formation position (position shift amount with respect to the normal position) may be shifted between the nozzle formed in the previous irradiation process and the nozzle formed in the subsequent irradiation process. is there.

  Thus, if the nozzle shape and the nozzle formation position (position shift amount) differ between nozzles formed in different regions by different irradiation processes, the liquid discharge amount and The discharge speed or the liquid landing position will be different. These problems cause, for example, density unevenness (banding) and streaks in an image formed on a recording medium in an image forming apparatus.

  In the above-mentioned Patent Document 1, each nozzle is formed by a plurality of times of laser irradiation, so that the above-described problems occur because the variation in the shape of the nozzles is equalized by the plurality of times of laser irradiation. It becomes difficult. However, forming each nozzle by a plurality of times of laser irradiation takes time and effort, which is very disadvantageous in terms of productivity.

  The object of the present invention is to minimize the influence on the image quality even when there is a difference in nozzle shape and nozzle formation position between nozzles formed in different irradiation processes on the base plate serving as the nozzle plate. There is to suppress.

Means for Solving the Problems and Effects of the Invention

A manufacturing method of a nozzle plate according to a first aspect of the present invention is a manufacturing method of a nozzle plate having a plurality of nozzles arranged in a predetermined first direction,
A first irradiation step of irradiating a first region of the base material to be the nozzle plate with a laser beam from a laser irradiation device to form a plurality of first nozzles in the first region; and the first region of the base material A second irradiation step of irradiating a second region different from the first region with a laser beam from a laser irradiation device to form a plurality of second nozzles in the second region;
In a second direction intersecting the first direction, at least a part of the second region of the base material in which the plurality of second nozzles are formed is formed in the first direction in which the plurality of first nozzles are formed. The first region and the second region are set so as to be aligned with one region, and the first region has a first adjacent region and a first non-adjacent region aligned in the first direction, and the second region The region has a second adjacent region and a second non-adjacent region arranged in the first direction, and the first adjacent region of the first region and the second adjacent region of the second region are the first The first non-adjacent region of the first region and the second non-adjacent region of the second region are arranged in two directions, and are not arranged in the second direction .
A method for manufacturing a nozzle plate according to a second aspect of the present invention is a method for manufacturing a nozzle plate having a plurality of nozzles arranged in a predetermined first direction, and is provided in a first region of a base material to be the nozzle plate. Irradiating laser light from a laser irradiation device to form a plurality of first nozzles in the first region, and laser irradiation to a second region different from the first region of the substrate A second irradiation step of irradiating a laser beam from the apparatus to form a plurality of second nozzles in the second region, and in the second direction intersecting the first direction, The first region and the second region are set so that at least a part of the second region where the plurality of second nozzles are formed is aligned with the first region where the plurality of first nozzles are formed. And irradiating the base material from the laser irradiation device. In the laser beam to be emitted, there is an intensity distribution in the first direction, and when the laser beam is irradiated onto the base material, a region where the high-intensity part of the laser light of the base material is irradiated; A region irradiated with a low intensity portion having a lower intensity than the high intensity portion of the laser light is aligned in the first direction, and the low intensity portion of the first region is irradiated in the first irradiation step. The region and the region irradiated with the high intensity portion of the second region in the second irradiation step are arranged in the second direction.

  In the present invention, the first region in which the plurality of first nozzles are formed by the first irradiation step and the second region in which the plurality of second nozzles are formed by the second irradiation step are in the first direction (nozzle arrangement). In the second direction intersecting the direction). That is, the first region and the second region overlap in the second direction. For this reason, when an image is formed on a recording medium moving in the second direction by the image forming apparatus having the nozzle plate of the present invention, at least a part of the image includes the first nozzle in the first region and the second nozzle in the second region. It is formed by two nozzles. Accordingly, even when the nozzle shape is different between the first nozzle and the second nozzle, or even when the nozzle formation position is different, density unevenness and streaks that occur in the image are less noticeable. In the present invention, each of the first nozzle and the second nozzle is formed by a single laser beam irradiation. Therefore, one nozzle as disclosed in Patent Document 1 mentioned above is provided. Unlike the method of forming by multiple irradiation processes, it does not take time and effort.

1 is a schematic plan view of a printer according to an embodiment. It is a partial top view of an inkjet head. It is the A section enlarged view of FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is the VV sectional view taken on the line of FIG. It is a figure which shows the manufacturing process of an inkjet head. It is a figure which shows the manufacturing process of the nozzle plate of the Example to which this invention is applied. It is a figure which shows the manufacturing process of the nozzle plate of the comparative example which does not apply this invention. It is a figure which shows the dot formed in the recording paper with the inkjet head which has a nozzle plate of the Example of FIG. It is a figure which shows the dot formed in the recording paper with the inkjet head which has the nozzle plate of the comparative example of FIG. It is a figure which shows the manufacturing process of the nozzle plate of a change form. It is a figure which shows the manufacturing process of the nozzle plate of another modified form. It is a figure which shows the division of the nozzle formation area of a base material plate of another modification. It is a schematic plan view of the inkjet printer which concerns on another modification.

  Next, an embodiment of the present invention will be described. The present embodiment is an example in which the present invention is applied to an inkjet printer that records an image by ejecting ink onto a recording sheet conveyed in a predetermined conveyance direction. FIG. 1 is a schematic plan view of the printer according to the present embodiment. 1 is parallel to the front and rear direction of the printer 1, parallel to the width direction of the recording paper, the left and right direction in FIG. 1 is the left and right direction of the printer 1, and the direction perpendicular to the paper surface in FIG. Are defined as the vertical direction of the printer 1 (the front side of the paper is the upper side).

(Printer configuration)
First, a schematic configuration of the printer will be described. As shown in FIGS. 1 to 3, the printer 1 includes a platen 2, an inkjet head 3, two transport rollers 4 and 5, a control device 6, and the like.

  A recording paper 100 is placed on the upper surface of the platen 2. An ink jet head 3 is disposed above the platen 2. The inkjet head 3 is a line-type head that is long in the left-right direction. The ink jet head 3 is connected to an ink tank (not shown), and ink is supplied from the ink tank. A plurality of nozzles 26 arranged in the left-right direction are formed on the lower surface (the surface on the other side of the paper) of the inkjet head 3.

  The two transport rollers 4 and 5 are arranged so as to sandwich the inkjet head 3 in the front-rear direction. These two transport rollers 4 and 5 are rotationally driven in synchronization by a motor (not shown) to transport the recording paper 100 in the transport direction.

  The control device 6 includes a ROM (Read Only Memory), a RAM (Random Access Memory), an ASIC (Application Specific Integrated Circuit) including various control circuits, and the like. The control device 6 executes various processes such as printing on the recording paper 100 by the ASIC according to the program stored in the ROM. For example, in the printing process, the control device 6 controls the ink jet head 3 to eject ink from the plurality of nozzles 26 toward the recording paper 100 based on a print command input from an external device such as a PC. Further, the control device 6 transports the recording paper 100 in the transport direction by the transport rollers 4 and 5. Thereby, a desired image is recorded on the recording paper 100.

(Configuration of inkjet head)
Next, details of the inkjet head 3 will be described. FIG. 2 is a partial plan view of the inkjet head 3. FIG. 3 is an enlarged view of a portion A in FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. In FIGS. 4 and 5, the ink filled in the flow path unit 20 of the inkjet head 3 is indicated by the symbol “I”. The ink jet head 3 of this embodiment includes a flow path unit 10 and a piezoelectric actuator 11.

  As shown in FIGS. 4 and 5, the flow path unit 10 has a structure in which five plates 21 to 25 are laminated. The lowermost plate 25 of the five plates 21 to 25 is a nozzle plate in which a plurality of nozzles 26 are formed, and is formed of a resin material such as polyimide. On the other hand, the remaining four plates 21 to 25 are formed with flow paths such as a manifold 28 and a pressure chamber 29 that communicate with the plurality of nozzles 26. The upper four plates 21 to 24 are made of a metal material such as stainless steel.

  As shown in FIG. 2, an ink supply hole 27 is formed on the upper surface of the flow path unit 10. Ink stored in an ink tank (not shown) is supplied to the ink supply hole 27. The flow path unit 10 includes two manifolds 28 extending in the paper width direction. Both the two manifolds 28 communicate with the ink supply hole 27.

  Further, the flow path unit 10 includes a plurality of nozzles 26 and a plurality of pressure chambers 29. The plurality of nozzles 26 are formed on the lowermost nozzle plate 25. As shown in FIG. 2, the plurality of nozzles 26 are arranged at a predetermined pitch P in the left-right direction (paper width direction), and two nozzle rows 39 a, respectively corresponding to the two manifolds 28. 39b is constituted. Between the two nozzle rows 39a and 39b, the position of the nozzle 26 in the left-right direction is shifted by a half (P / 2) of the arrangement pitch P of each nozzle row 39. That is, all the nozzles 26 of the inkjet head 3 are distributed in two rows in the transport direction and arranged in a so-called staggered pattern, and are arranged at a pitch of P / 2 in the paper width direction. In this embodiment, the arrangement direction of the nozzles 26 is orthogonal to the conveyance direction, but the arrangement direction of the nozzles 26 may be a direction that intersects the conveyance direction at an angle other than 90 degrees.

  The plurality of pressure chambers 29 are also arranged in the paper width direction like the plurality of nozzles 26 to form two rows of pressure chambers. Each pressure chamber 29 has an oval shape that is long in the transport direction. As shown in FIGS. 3 and 4, one end of each pressure chamber 29 communicates with the manifold 28 through a communication hole 30 formed in the plate 22. Moreover, the other end part of each pressure chamber is connected with the nozzle 26 via the communication holes 31-33 formed in the plates 22-24, respectively. As described above, as indicated by arrows in FIG. 4, a plurality of individual flow paths are formed in the flow path unit 10 so as to branch from the manifold 28 and reach the nozzles 26 through the pressure chambers 29.

  As shown in FIGS. 4 and 5, the piezoelectric actuator 11 includes an ink sealing film 40, piezoelectric layers 44 and 45, a plurality of individual electrodes 42, and a common electrode 46. The ink sealing film 40 is bonded to the upper surface of the flow path unit 10 so as to cover the plurality of pressure chambers 29. The two piezoelectric layers 44 and 45 are laminated on the upper surface of the ink sealing film 40. The plurality of individual electrodes 42 are arranged on the upper surface of the upper piezoelectric layer 44 so as to face the plurality of pressure chambers 29, respectively. The common electrode 46 is disposed across the plurality of pressure chambers 29 between the two piezoelectric layers 44 and 45.

  The portion of the upper piezoelectric layer 44 sandwiched between the individual electrode 42 and the common electrode 46 is polarized in the thickness direction of the piezoelectric layer 44. This portion is a portion that contracts when a potential difference is generated between the individual electrode and the common electrode 46 and causes the ink sealing film 40 to bend and deform, and is hereinafter referred to as an active portion 41.

  A wiring member (not shown) connected to the control device 6 of the printer 1 is connected to the plurality of individual electrodes 42. A driver IC 47 is mounted on the wiring member. The driver IC 47 receives a signal from the control device 6 and supplies a drive signal to each of the plurality of individual electrodes 42.

  When a drive signal is supplied from a driver IC 47 to a certain individual electrode 42, an electric field in a direction parallel to the polarization direction acts on the active portion 41 of the piezoelectric layer 44 sandwiched between the individual electrode 42 and the common electrode 46. The active part 41 contracts in the surface direction. Due to the contraction of the active portion 41, the two piezoelectric layers 44 and 45 are deformed so as to bend toward the pressure chamber 29 side. As a result, when the volume of the pressure chamber 29 changes, ejection energy is imparted to the ink in the pressure chamber 29, and ink is ejected from the nozzles 26 communicating with the pressure chamber 29.

  Next, the manufacturing process of the inkjet head 3 described above will be described. Here, the description will mainly focus on the manufacture of the flow path unit 10 (particularly, the nozzle plate 25). FIG. 6 is a diagram illustrating a manufacturing process of the inkjet head 3.

  First, regarding the flow path unit 10, the upper four metal plates 21 to 24 among the five plates constituting the flow path unit 10 are etched to form a pressure chamber 29, a manifold 28, and a communication hole, respectively. Channel holes such as 30 to 34 are formed. Further, although detailed description is omitted, separately from the manufacture of the flow path unit 10, the two piezoelectric layers 44 and 45 of the piezoelectric actuator 11 are laminated, fired, and the individual electrodes 42 to the piezoelectric layers 44 and 45, Processes such as formation of the common electrode 46 are performed.

  Then, first, as shown in FIG. 6A, a base plate 50 of a synthetic resin such as polyimide, which becomes the nozzle plate 25 after the formation of the nozzles 26, is bonded to the plate 24 in which the communication holes 33 are formed. Paste with an agent. Next, as shown in FIG. 6 (b), a plurality of holes 51a corresponding to the pattern of the nozzles 26 are formed on the upper side (plate side) of the laminated body of the two plates 24 and 50. A mask 51 is installed, and laser light is irradiated from above the light shielding mask 51 by a laser irradiation device. A plurality of nozzles 26 are formed on the base plate 50 by the laser beams respectively passing through the plurality of holes 51a of the light shielding mask 51. The type of laser processing is not particularly limited, but an excimer laser is preferably used. The formation of the nozzle 26 by laser processing in FIG. 6B will be described in detail later.

  The main purpose of forming the plurality of nozzles 26 on the base plate 50 after laminating the base plate 50 and another plate 24 is that the base plate 50 is made of synthetic resin, and is rigid. This is because the metal plate 24 is laminated to increase the rigidity and the handling property of the base plate 50 is improved.

  Next, as shown in FIG. 6C, the laminated body of the plate 24 and the nozzle plate 25 and the other plates 21 to 23 constituting the flow path unit 10 are communicated with each other. Align and join with adhesive. The ink sealing film 40 of the piezoelectric actuator 11 is bonded to the plate 21 on which the plurality of pressure chambers 29 are formed with an adhesive so as to cover the plurality of pressure chambers 29. Thereafter, as shown in FIG. 6D, the laminate of the two piezoelectric layers 44 and 45 on which the individual electrode 42 and the common electrode 46 are formed is bonded to the upper surface of the ink sealing film 40 with an adhesive. . Through the above steps, the manufacture of the ink jet head including the flow path unit 10 and the piezoelectric actuator 11 is completed.

  Next, the manufacturing process of the nozzle plate 25 will be described in detail. The inkjet head 3 of the present embodiment is a line-type inkjet head that is long in the paper width direction, and a number of nozzles 26 are arranged on the nozzle plate 25 along the longitudinal direction. When manufacturing such a nozzle plate 25, if all the nozzles 26 are irradiated with a single laser beam to the base plate 50 that becomes the nozzle plate 25, the length is almost the same as that of the base plate 50. A long shading mask 51 is required. However, there is a limit to increasing the size of the light-shielding mask 51 due to restrictions on the manufacturing surface of the light-shielding mask 51.

  Therefore, it is desirable to perform laser irradiation for forming the nozzle 26 in a plurality of times. That is, the entire nozzle formation area of the base plate 50 is divided into a plurality of areas, and the light shielding mask 51 having a smaller size than the base plate 50 is used to irradiate each of the divided areas with laser light. Repeat in order.

  Specifically, in the present embodiment, the nozzle formation region of the base plate 50 is divided into two regions, and a light shielding mask 51 is installed in each of these two regions and irradiated with laser light. At that time, how to set the division of the nozzle formation region of the base plate 50 is important. Hereinafter, two examples of the division of the nozzle formation region of the base plate 50 will be described in comparison.

  7A and 7B are diagrams showing a manufacturing process of a nozzle plate according to an embodiment to which the present invention is applied, in which FIG. 7A is a top view of the base plate 50, FIG. 7B is a top view of the light shielding mask 51, and FIG. (A) CC sectional drawing when forming the nozzle 26 in a 1st area | region, (d) is DD sectional drawing of (a) when forming the nozzle 26 in a 2nd area | region. On the other hand, FIG. 8 is a view showing a manufacturing process of a nozzle plate of a comparative example to which the present invention is not applied, where (a) is a top view of the base plate 50, (b) is a top view of the light shielding mask 151, (c) ) Is a cross-sectional view taken along the line C-C when the nozzle 26 is formed in the first region, and FIG. 5D is a cross-sectional view taken along the line D-D when the nozzle 26 is formed in the second region. In FIG. 6B described above, the nozzle 26 is formed in a state where the plate 24 is laminated on the base plate 50, but in FIGS. 7 and 8, the drawing is simplified. For the sake of simplicity, the illustration of the plate 24 is omitted.

[Examples]
First, the embodiment of FIG. 7 will be described in detail.

(Division of area)
As shown in FIG. 7A, the base plate 50 is a plate having a rectangular planar shape that is long in one direction. In the embodiment of FIG. 7, the nozzle formation region of the base plate 50 is divided into two regions, a first region 61 and a second region 62, in the longitudinal direction of the base plate 50. However, the first region 61 and the second region 62 partially overlap in the short direction of the base plate 50, that is, in the direction orthogonal to the arrangement direction of the nozzles 26. More specifically, the first adjacent region 63 on the right side of the first region 61 is aligned with the second adjacent region 65 on the left side of the second region 62 in the transport direction. The first non-adjacent region 64 on the left side of the first region 61 is not aligned with the second region 62, and the second non-adjacent region 66 on the right side of the second region 62 is also the first region 61. Are not lined up. The longitudinal direction of the base plate 50 (nozzle plate 25) corresponds to the first direction of the present invention, and in the printer 1 of FIG. 1, the longitudinal direction is parallel to the paper width direction. Further, the short side direction of the base plate 50 (nozzle plate 25) corresponds to the second direction of the present invention, and in the printer 1 of FIG.

(Shading mask)
As shown in FIG. 7B, the light shielding mask 51 installed on the base plate 50 has a rectangular planar shape. In the light shielding mask 51, a plurality of holes 51a corresponding to the nozzle formation patterns of the first region 61 and the second region 62 shown in FIG. 7A are formed. Specifically, the plurality of holes 51a are arranged at an arrangement pitch P along the longitudinal direction of the light shielding mask 51, thereby constituting two rows of hole groups 53a and 53b. The hole group 53b has a smaller number of holes 51a than the hole group 53a, and the positions of the individual holes 51a are shifted by P / 2 in the arrangement direction with respect to the hole group 53a. Accordingly, the light shielding mask 51 includes a region A in which the arrangement density of the holes 51a is high and a region B in which the arrangement density of the holes 51a is low.

  Note that one of the light shielding mask 51 and the base plate 50 can be relatively moved and relatively rotated within a horizontal plane with respect to the other. The light shielding mask 51 may be configured to be movable and rotatable with respect to the base plate 50, or the base plate 50 may be configured to be movable and rotatable with respect to the light shielding mask 51. By moving the light shielding mask 51 relative to the base plate 50 and rotating it relative to each other, the same light shielding mask 51 can be placed immediately above the first region 61 and the second region 62, respectively. ing.

(First irradiation process)
As shown in FIG. 7C, first, the light shielding mask 51 of FIG. 7B is installed on the first region 61 of the base plate 50. Then, the laser light is irradiated from the laser irradiation device 52 toward the light shielding mask 51, and the plurality of nozzles 26 are formed in the first region 61 of the base plate 50 by the laser light respectively passing through the plurality of holes 51 a of the light shielding mask 51. Form.

(Second irradiation process)
After the first irradiation step, the light shielding mask 51 is relatively moved and relatively rotated with respect to the base plate 50, and the light shielding mask 51 is placed on the second region 62 of the base plate 50. Then, similarly to the first irradiation step, laser light is irradiated from the laser irradiation device 52 toward the light shielding mask 51 to form the plurality of nozzles 26 in the second region 62 of the base plate 50.

  In the following description, the nozzles 26 formed in the first region 61 of the base plate 50 by the first irradiation step are referred to as “first nozzles 26a” or simply “nozzles 26a”. Further, the nozzle 26 formed in the second region 62 of the base plate 50 by the second irradiation step is referred to as a “second nozzle 26b” or simply “nozzle 26b”.

  In addition, on the first non-adjacent region 64 of the first region 61 and the second non-adjacent region 66 of the second region 62, the region A of the light shielding mask 51 in which the holes 51a are arranged with high density is installed. . Accordingly, in the first non-adjacent region 64 and the second non-adjacent region 66, the arrangement pitch of the nozzles 26 is P / 2. On the other hand, on the first adjacent region 63 of the first region 61 and the second adjacent region 65 of the second region 62, the region B of the light shielding mask 51 in which the holes 51a are arranged at a low density is installed. Therefore, in the first adjacent region 63 and the second adjacent region 65, the arrangement pitch of the nozzles 26 is P, respectively. However, in the total of these two regions 63 and 65, the nozzles 26 (26a and 26b) are arranged at a pitch P / 2 in the paper width direction, and the first non-adjacent region 64 and the second region are arranged. This is equal to the arrangement pitch (P / 2) of the nozzles 26 in the non-adjacent region 66. Therefore, the arrangement pitch of the nozzles 26 is P / 2 over the entire length of the base plate 50.

[Comparative example]
Next, the comparative example of FIG. 8 will be described. As shown in FIG. 8A, also in this comparative example, the nozzle formation region of the base plate 50 is divided into two regions, a first region 161 and a second region 162, in the longitudinal direction of the base plate 50. Yes. However, here, the nozzle formation region is simply divided into left and right, and the first region 161 and the second region 162 do not overlap in the short direction of the base plate 50. Further, as shown in FIG. 8B, the light shielding mask 151 is formed with a plurality of holes 151a corresponding to the nozzle formation patterns of the first region 161 and the second region 162.

The step of irradiating the base plate 50 with laser light is the same as in the embodiment. That is, first, a light-shielding mask 151 is placed over the first region 161 of the substrate plate 50, by irradiating a laser beam from the laser irradiation device 152 to the light-shielding mask 151, a plurality of nozzles 26 in the first region 16 1 (26a) is formed. Next, a light shielding mask 151 is installed on the second region 162 of the base plate 50, and a laser beam is irradiated from the laser irradiation device 152 to the light shielding mask 151, whereby a plurality of nozzles 26 (26b) are disposed in the second region 162. ).

  By the way, in the manufacturing process of the nozzle plate 25, when the laser light irradiation process is divided into a plurality of times, the following problems may occur.

  As described above, since the same light shielding mask 51 (151) is used in the first irradiation process and the second irradiation process, the first nozzle 26a originally formed in the first irradiation process and the second irradiation process are used. The formed second nozzle 26b should have the same shape. However, actually, the intensity (characteristic) of the laser light emitted from the laser irradiation apparatus changes between different laser irradiation processes. For example, in the case of an excimer laser, an intensity change due to a temporal change in the concentration of an inert gas necessary for generating laser light can be considered. Further, a temperature change in the laser irradiation apparatus also affects the intensity of the output laser light. Due to such a change in the intensity characteristics of the laser light, the shape (particularly, the nozzle diameter) of the nozzles 26 may differ between the nozzles 26 formed in different irradiation processes.

  Further, as described above, after the first irradiation process and before the second irradiation process, the light shielding mask 51 (151) is moved relative to the base plate 50 and relatively rotated. It is necessary to change the relative position and relative angle between the two. Due to the movement error or rotation error at that time, the formation position (regular position) of the nozzle 26 between the first nozzle 26a formed in the first irradiation process and the second nozzle 26b formed in the second irradiation process. May be different from each other.

Thus, different irradiation steps Roh nozzle 26a is formed in, among 26b, the difference in the formation positions of the shape and the nozzles 26 of the nozzle 26 is present, the first nozzle 26a formed in the first irradiation step And the second nozzle 26b formed in the second irradiation step, the ink discharge amount and the ink landing position are different. In this regard, in the embodiment to which the present invention is applied, the first region 61 of the base plate 50 that is irradiated with laser light in the first irradiation step and the second region 62 that is irradiated with laser light in the second irradiation step. Are arranged in a direction perpendicular to the arrangement direction of the nozzles 26. For this reason, as described below, it is possible to suppress the deterioration of the image quality of the recorded image due to the difference in the discharge amount and the landing position deviation.

  FIG. 9 is a diagram illustrating dots formed on the recording paper by the ink jet head having the nozzle plate 25 of the example. FIG. 10 is a diagram showing dots formed on the recording paper by the ink jet head having the nozzle plate 25 of the comparative example.

  9A and 10A, the diameter of the second nozzle 26b formed in the second regions 62 and 162 of the base plate 50 is the first nozzle 26a formed in the first regions 61 and 161. FIG. The case where it is smaller than the diameter of is shown. In FIG. 10A of the comparative example, the dots Da formed by the first nozzles 26a of the first area 161 are arranged in the left area of the recording paper, and formed by the second nozzles 26b of the second area 162 in the right area. The dots Db are arranged. Here, when the diameter of the second nozzle 26b in the second area 162 is small, the dots Db in the right area of the recording paper are smaller than the dots Da in the left area, and the density in the right area is lower than that in the left area. This difference in density causes banding in the recorded image.

  On the other hand, in FIG. 9A of the embodiment, the dots Da formed by the first nozzles 26a of the first adjacent region 63 of the first region 61 and the first region 61 in the central region in the sheet width direction of the recording paper. The dots Db formed by the second nozzles 26b in the second adjacent region 65 of the two regions 62 are mixed. Therefore, even if the size of the dot Db formed by the second nozzle 26b in the second region 62 is different from the dot Da formed by the first nozzle 26a in the first region 61, two types having different sizes are used. Since the dots Da and Db are arranged in a mixed manner, density unevenness is suppressed.

  9B and 10B, the positions of the second nozzles 26b formed in the second regions 62 and 162 of the base plate 50 are shifted to the right with respect to the normal positions. Shows the case. In FIG. 10B of the comparative example, the dot Db in the right region of the recording paper is shifted to the right as a whole with respect to the dot Da in the left region, and a gap G is generated between the two regions. In the left and right regions of the gap G, since the dots Da and Db are uniformly arranged, the gap G in which the density is locally reduced is visually recognized as a white stripe by the person viewing the image. .

  On the other hand, in FIG. 9B of the embodiment, the dots Db formed by the second nozzles 26b of the second adjacent region 65 of the second region 62 in the central region in the sheet width direction of the recording paper are the first. The dot Da formed by the first nozzle 26a in the second adjacent region of the one region 61 is shifted to the right. At this time, a gap is formed between the two types of dots Da and Db, but there are also portions where the two types of dots Da and Db overlap each other. That is, in this central region in the paper width direction, the portions where the two types of dots Da and Db are separated and the density is low, and the portions where the two types of dots Da and Db are overlapped and the density is high appear alternately. However, at the human visual limit (about 300 to 400 dpi), it is difficult to distinguish and distinguish the low-density part and the dark part, and the person who sees the image cannot visually recognize it as a white stripe or a black stripe. Further, in the central region in the paper width direction, the above-described lightly dark portions and dark portions appear alternately, so the density of the entire central region is the left region where the dots Da and Db are arranged uniformly. And the concentration in the right region is not so different. Therefore, the entire central region does not stand out from the left and right regions.

  As described above, in the present embodiment, the first region 61 in which the plurality of first nozzles 26a are formed by the first irradiation step and the second region in which the plurality of second nozzles 26b are formed by the second irradiation step. 62 are arranged in the lateral direction of the base plate 50, which is orthogonal to the arrangement direction of the nozzles 26. That is, the first region 61 and the second region 62 overlap in the short direction. Therefore, when an image is formed on the recording paper 100 conveyed in the conveyance direction parallel to the short direction by the inkjet head 3, a part of the image is formed in the first adjacent area 63 of the first area 61. The first nozzle 26 a and the second nozzle 26 b formed in the second adjacent region 65 of the second region 62 are formed. Therefore, even when the shape of the nozzle 26 is different between the first nozzle 26a in the first region 61 and the second nozzle 26b in the second region 62, or when the formation position of the nozzle 26 is different, Density unevenness and streaks that occur in the image are less noticeable. In addition, since both the first nozzle 26a in the first region 61 and the second nozzle 26b in the second region 62 are formed in one laser irradiation step, they are disclosed in Patent Document 1 mentioned above. Compared to a method in which one nozzle 26 is formed by a plurality of laser irradiation processes as in the method, it takes less time and effort.

  In the present embodiment, the first adjacent region 63 of the first region 61 and the second adjacent region 65 of the second region 62 of the base plate 50 are lined up in the short direction of the base plate 50, The first non-adjacent region 64 of the first region 61 and the second non-adjacent region 66 of the second region 62 are not aligned in the short direction of the base plate 50. That is, the first region 61 and the second region 62 partially overlap in the first adjacent region 63 and the second adjacent region 65. Thereby, the nozzle group composed of the plurality of first nozzles 26a formed in the first irradiation step and the nozzle group composed of the plurality of second nozzles 26b formed in the second irradiation step partially overlap. . Accordingly, by performing the irradiation process twice, a nozzle group having a longer arrangement length than the nozzle group formed in each irradiation process can be formed in the entire longitudinal direction of the base plate 50. This is particularly effective when the nozzle plate 25 of a long line type head is manufactured.

  In the present embodiment, the arrangement pitch of the nozzles 26 in each of the first adjacent region 63 of the first region 61 and the second adjacent region 65 of the second region 62 is set to the first non-adjacent region of the first region 61. 64 and the arrangement pitch of the nozzles 26 in each of the second non-adjacent regions 66 of the second region 62 are made larger. Thereby, the arrangement pitch of the nozzles 26 (26a, 26b) in the region where the first adjacent region 63 and the second adjacent region 65 are combined is set to the arrangement pitch of the nozzles 26a in the first non-adjacent region 64 and the second non-adjacent region 64. The arrangement pitch of the nozzles 26b in the adjacent region 66 can be made the same. That is, the arrangement pitch of the nozzles 26 can be made uniform over the entire longitudinal direction of the base plate 50 by two irradiation processes.

  In the embodiment described above, the base plate 50 serving as the nozzle plate 25 corresponds to the base material of the present invention. The light shielding mask 51 corresponds to the nozzle forming member of the present invention. The hole 51a of the light shielding mask 51 corresponds to the light passage part of the present invention.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

1] As a nozzle forming member used for irradiating the laser beam emitted from the laser irradiation device in a concentrated manner only on a specific portion of the base material, in addition to the light shielding mask 51 of the above embodiment, a microlens is used. It can also be used. The microlens is a general term for lenses having a minute lens portion having a diameter of less than 1 mm in general. Among these, a silicon microlens in which a microlens portion is formed on a silicon substrate by a semiconductor process is known.

  FIG. 11 is an explanatory diagram of a process of forming the nozzles 26 in the first region 61 and the second region 62 of the base plate 50 using the silicon microlens 71. The setting for dividing the first region 61 and the second region 62 of the base plate 50 in this modification shown in FIG. 11A is the same as the example described in the above embodiment (see FIG. 7A). The same. As shown in FIG. 11B, the silicon microlens 71 has a plurality of lens portions 71 a corresponding to the nozzle formation patterns of the first region 61 and the second region 62 of the base plate 50.

(First irradiation process)
First, as shown in FIG. 11C, after the silicon microlens 71 is placed on the first region 61 of the base plate 50, laser light is irradiated from the laser irradiation device 52 toward the silicon microlens 71. To do. The laser light applied to the silicon microlens 71 passes through the lens portion 71a while being condensed in each of the plurality of lens portions 71a. A plurality of first nozzles 26 a are formed in the first region 61 of the base plate 50 by the laser beams that have passed through the plurality of lens portions.

(Second irradiation process)
Next, as shown in FIG. 11 (d), the silicon microlens 71 is relatively moved and rotated relative to the base plate 50, placed on the second region 62 of the base plate 50, and then subjected to laser irradiation. Laser light is irradiated from the device 52 toward the silicon microlens 71. The laser light applied to the silicon microlens 71 passes through the lens portion 71a while being condensed in each of the plurality of lens portions 71a. A plurality of second nozzles 26 b are formed in the second region 62 of the base plate 50 by the laser beams that have passed through the plurality of lens portions, respectively.

  In the embodiment of FIG. 11, the silicon microlens 71 corresponds to the nozzle forming member of the present invention. Further, the plurality of lens portions 71a correspond to the plurality of light passing portions of the present invention.

  When the silicon microlens 71 is used as shown in FIG. 11, the planar size of the silicon microlens 71 is large in order to form as many nozzles 26 as possible in one irradiation process and reduce the number of irradiation processes. Is preferred. However, since the silicon microlens 71 is manufactured from a silicon wafer, the size of the lens is restricted by the size of the silicon wafer. Here, a silicon wafer having a diameter of 50 mm (2 inches) to 300 mm (12 inches) is known. However, if a wafer with a large size is used, the cost becomes high. 6 inches) is preferably used. In that case, in the silicon microlens 71, the arrangement length L1 of the plurality of lens portions 71a is 105 mm or more and less than 150 mm.

  Using such silicon microlenses 71, in the first irradiation step, a plurality of first nozzles 26a arranged in a length of 105 mm or more in the paper width direction are formed in the first region 61 of the base plate 50. Further, in the second irradiation step, a plurality of second nozzles 26 b arranged in a length of 105 mm or more in the paper width direction are formed in the second region 62 of the base plate 50. Furthermore, the 1st area | region 61 in which the some 1st nozzle 26a is formed in the 1st irradiation process of the base material plate 50, and the 2nd area | region 62 in which the some 2nd nozzle 26b is formed in the 2nd irradiation process are as follows. It is set so as to partially overlap in the short direction of the base plate 50. Therefore, a plurality of nozzles 26 having an array length L2 of 210 mm or more can be formed on the base plate 50 by two irradiation steps.

2] About the 1st field 61 and the 2nd field 62, it is also possible to set as follows, for example.

(1) In general, the intensity of the laser beam irradiated in one irradiation process cannot be completely constant within the irradiation range, and it is normal that some intensity distribution is generated in the laser beam. It is. For example, there is a tendency peculiar to each laser irradiation device 52 such that the intensity is stronger at the center side of the irradiation range and becomes weaker toward the end side. As described above, the diameter of the nozzle 26 varies even when the intensity distribution is generated in the paper width direction in the laser light irradiated in one irradiation process.

  In that case, for example, when two regions of the first region 61 and the second region 62 arranged in the short direction of the base plate 50 are irradiated with a high-intensity portion of laser light, respectively, these two regions In addition, the large diameter nozzles 26 are formed in a concentrated manner, and as a result, density unevenness occurs in the recorded image. From this point of view, it is preferable not to irradiate the high intensity portion or the low intensity portion of the laser light on both of the two regions.

  Similarly to FIG. 7 of the embodiment, as shown in FIG. 12A, the nozzle formation region of the base plate 50 is divided into a first region 61 and a second region 62. Further, the first adjacent region 63 of the first region 61 and the second adjacent region 65 of the second region 62 of the base plate 50 are aligned in the short direction of the base plate 50. As shown in FIGS. 12B and 12C, it is assumed that the laser beam irradiated from the laser irradiation apparatus has an intensity distribution (intensity fluctuation) in the longitudinal direction of the base plate 50. In FIGS. 12B and 12C, the difference in arrow length indicates the difference in laser light intensity. The central portion of the laser beam is a high-intensity portion having high intensity, and both side portions thereof are low-intensity portions having lower intensity than the central portion.

  One region of the first adjacent region 63 and one region of the second region 62 aligned therewith are irradiated with portions having different laser light intensities. That is, as shown in FIGS. 12B and 12C, the region where the high intensity portion of the laser light is irradiated in the first adjacent region 63 and the low intensity portion of the laser light in the second adjacent region 65 are The region to be irradiated is lined up in the short direction of the base plate 50. In addition, the region of the first adjacent region 63 that is irradiated with the low-intensity portion of the laser light and the region of the second adjacent region 65 that is irradiated with the high-intensity portion of the laser light are short of the base plate 50. It is lined up in the direction.

  As a result, the nozzle 26 having a large hole diameter due to high laser light intensity and the nozzle 26 having a small hole diameter due to low laser light intensity are aligned in the short direction of the base plate 50. Therefore, density unevenness of the recorded image is suppressed.

(2) However, the present invention is not limited to irradiating the region where the first region 61 and the second region 62 overlap with different intensity portions of the laser light. For example, when the intensity distribution (intensity fluctuation) of the laser beam within the irradiation range is small, the region where the first region 61 and the second region 62 overlap each other may be irradiated with a high-intensity portion of the laser beam.

(3) The nozzle formation region of the base plate 50 may be divided into three or more regions, and the nozzles 26 may be formed by irradiating the three or more regions with laser light, respectively. For example, in FIG. 13A, the first region 61, the second region 62, and the third region 67 that are aligned in the longitudinal direction of the base plate 50 are set on the base plate 50. Of these three regions 61, 62, 67, the first region 61 and the second region 62 are arranged in the short direction of the base plate 50, and the second region 62, the third region 67, Are arranged in the short direction of the base plate 50. Alternatively, the three areas of the first area 61, the second area 62, and the third area 67 of the base plate 50 may be arranged in order in the short direction of the base plate 50.

(4) The entire first region 61 and the entire second region 62 may be arranged in the short direction of the base plate 50. For example, in FIG. 13B, the first region 61 is a region where the entire one nozzle row 39a shown in FIG. 2 is arranged, and the second region 62 is the other nozzle row shown in FIG. This is a region where the entire 39b is arranged. The entire first region 61 and the entire second region 62 are arranged in the short direction of the base plate 50. If the nozzle plate 25 formed as shown in FIG. 13B is used, the dots Da formed by the first nozzles 26a in the first region 61 in the entire longitudinal direction of the nozzle plate 25 (the entire width direction of the recording paper 100). And the dots Db formed by the second nozzles 26b in the second region 62 are mixed. Accordingly, uneven density due to differences in the sizes and landing positions of the two types of dots Da and Db is less noticeable.

3] In the above-described embodiment, the base plate 50 serving as the nozzle plate 25 is a plate formed of synthetic resin. However, the material of the base plate 50 is not particularly limited. For example, the base plate 50 may be a metal plate having higher rigidity than the synthetic resin plate, for example.

  Moreover, in the said embodiment, as shown in FIG. 6, after laminating | stacking another plate 24 on the base plate 50, the several nozzle 26 is formed in the base plate 50, However, Depending on the rigidity, the number of plates to be laminated in advance can be changed as appropriate. Furthermore, when the base plate 50 has high rigidity, it is not necessary to stack another plate on the base plate 50 before forming the plurality of nozzles 26.

4] When the shape of the nozzle 26 is different between the first region 61 and the second region 62, the amount of ink discharged between the first nozzle 26a in the first region 61 and the second nozzle 26b in the second region 62 You may control the operation | movement of the piezoelectric actuator which provides discharge energy to each nozzle 26 so that the difference in discharge speed may become small. For example, the waveform of the drive signal and the drive voltage are made different between the individual electrode corresponding to the nozzle 26 having a large diameter and the individual electrode corresponding to the nozzle 26 having a small diameter.

5] The device for applying ejection energy to each nozzle 26 is not limited to the piezoelectric actuator exemplified in the above embodiment. For example, a device having a heat generating resistor for applying thermal energy to the ink and causing the ink to undergo film boiling by heating with the heat generating resistor and ejecting from the nozzle 26 may be used.

6] In the above embodiment, the example in which the present invention is applied to the nozzle plate of a line-type inkjet head in which nozzles are arranged along the paper width direction has been described. On the other hand, the present invention can also be applied to a so-called serial type ink jet head in which nozzles are arranged along the transport direction and ink is ejected while moving in the paper width direction. An inkjet printer 81 shown in FIG. 14 includes a carriage 82, an inkjet head 83 mounted on the carriage 82, and conveyance rollers 84 and 85 that convey recording paper in the conveyance direction. The carriage 82 reciprocates in the scanning direction (paper width direction) orthogonal to the transport direction by the carriage drive motor 86. The ink jet head 83 is connected to the ink cartridge 87 by a tube (not shown). The ink jet head 83 discharges ink from the plurality of nozzles 96 to the recording paper 100 while moving in the scanning direction together with the carriage 82.

  Also in the serial type ink jet head 83 described above, for example, the number of nozzles 96 arranged in the transport direction is large, and it is difficult to form these nozzles 96 on the base material to be the nozzle plate 90 at once by laser processing. In such a case, the present invention is suitable. In this case, for example, as shown in FIG. 14, the base material to be the nozzle plate 90 is divided into a first region 91 and a second region 92 that partially overlap in the scanning direction, and a laser irradiation process is performed on each of them. Can be done.

25 nozzle plate 26a first nozzle 26b second nozzle 50 base plate 51a hole 51 light shielding mask 52 laser irradiation device 61 first region 62 second region 63 first adjacent region 64 first non-adjacent region 65 second adjacent region 66 second 2 Non-adjacent region 71 Silicon microlens 71a Lens part 83 Inkjet head 90 Nozzle plate 91 First region 92 Second region 96 Nozzle

Claims (5)

A method of manufacturing a nozzle plate having a plurality of nozzles arranged in a predetermined first direction,
A first irradiation step of forming a plurality of first nozzles in the first region by irradiating laser light from a laser irradiation device to the first region of the base material to be the nozzle plate;
A second irradiation step of irradiating a second region different from the first region of the base material with a laser beam from a laser irradiation device to form a plurality of second nozzles in the second region;
In a second direction intersecting the first direction, at least a part of the second region of the base material in which the plurality of second nozzles are formed is formed in the first direction in which the plurality of first nozzles are formed. Set the first area and the second area so as to line up with one area ,
The first region has a first adjacent region and a first non-adjacent region arranged in the first direction,
The second region has a second adjacent region and a second non-adjacent region arranged in the first direction,
The first adjacent region of the first region and the second adjacent region of the second region are aligned in the second direction;
The method of manufacturing a nozzle plate, wherein the first non-adjacent region of the first region and the second non-adjacent region of the second region are not aligned in the second direction . In the first irradiation step, the arrangement pitch of the first nozzles in the first adjacent region in the first direction is greater than the arrangement pitch of the first nozzles in the first non-adjacent region in the first direction. Make it bigger
In the second irradiation step, the arrangement pitch of the second nozzles in the second adjacent region in the first direction is greater than the arrangement pitch of the second nozzles in the second non-adjacent region in the first direction. The method of manufacturing a nozzle plate according to claim 1 , wherein the nozzle plate is enlarged. A method of manufacturing a nozzle plate having a plurality of nozzles arranged in a predetermined first direction,
A first irradiation step of forming a plurality of first nozzles in the first region by irradiating laser light from a laser irradiation device to the first region of the base material to be the nozzle plate;
A second irradiation step of irradiating a second region different from the first region of the base material with a laser beam from a laser irradiation device to form a plurality of second nozzles in the second region;
In a second direction intersecting the first direction, at least a part of the second region of the base material in which the plurality of second nozzles are formed is formed in the first direction in which the plurality of first nozzles are formed. Set the first area and the second area so as to line up with one area ,
In the laser beam irradiated to the base material from the laser irradiation device, there is an intensity distribution in the first direction,
When the laser beam is irradiated onto the substrate, there are a region of the substrate that is irradiated with the high-intensity portion of the laser beam and a low-intensity portion that is lower in intensity than the high-intensity portion of the laser beam. The irradiated region is aligned in the first direction,
The region irradiated with the low intensity portion of the first region in the first irradiation step and the region irradiated with the high intensity portion of the second region in the second irradiation step are in the second direction. A method for manufacturing a nozzle plate, characterized by being arranged . In the first irradiation step, a nozzle forming member having a plurality of light passing portions is installed on the first region of the base material, and the nozzle forming member is irradiated with the laser light from the laser irradiation device. Forming the plurality of first nozzles in the first region,
In the second irradiation step, the same nozzle forming member as that used in the first irradiation step is installed in the second region of the base material, and the laser irradiation device applies the nozzle forming member. The method of manufacturing a nozzle plate according to claim 1, wherein the plurality of second nozzles are formed in the second region by irradiating the laser beam. As before Kino nozzle forming member, the first having a plurality of lens portions corresponding to the plurality of light-passing section arranged in the direction and sequence length in said first direction of said plurality of lens portions is 105mm Using a silicon microlens that is less than 150 mm,
In the first irradiation step, before Symbol first region, forming a plurality of first nozzles arranged above the length 105mm in the first direction,
In the second irradiation step, before Symbol second region, by forming a plurality of second nozzles arranged above the length 105mm in the first direction,
Over prior Symbol the second region and the first region, according to claim 4, wherein the plurality of first nozzles of the plurality of second nozzles, arranged in 210mm or longer in the first direction Nozzle plate manufacturing method.