JP4601493B2 - Sheet processing apparatus and method of manufacturing sheet processing apparatus - Google Patents

Description

  The present invention relates to a sheet processing apparatus for forming a plurality of holes in a ceramic green sheet and a method for manufacturing the sheet processing apparatus.

  In recent years, multilayer ceramic substrates have been used as electronic circuit modules for various electronic devices. In the manufacturing process of the multilayer ceramic substrate, through-hole processing is performed on the ceramic green sheet before firing. As shown in FIG. 4C, the sheet processing apparatus used in the through hole processing is configured by a mold 33 having a protrusion corresponding to the through hole and a mold having a hole corresponding to the protrusion. The The sheet processing apparatus sets a ceramic green sheet between a mold having a protrusion and a mold having a hole, and the protrusion penetrates the ceramic green sheet, thereby forming a plurality of holes in the ceramic green sheet ( For example, see Patent Document 1).

  Of the molds used in this sheet processing apparatus, a mold having protrusions is produced by the method described below.

  First, as shown in FIG. 4A, a photoresist 5 is applied on the flat plate 2 made of metal.

  As shown in FIG. 4B, the photoresist 5 is exposed using an exposure mask 6 having an exposure pattern 6a at a predetermined position.

  As shown in FIG. 4C, the portion of the photoresist 5 corresponding to the exposure pattern 6a remains on the flat plate 2 by chemical etching, and only the surface portion of the other portions is removed by chemical etching.

As shown in FIG. 4D, the photoresist 5 is removed by chemical etching to obtain a mold 33 having protrusions 2P at portions corresponding to the exposure pattern 6a.
JP-A-6-1626

  However, the processing by etching causes problems such as the deformation of the shape of the protrusion 2P and the deterioration of the flatness of the flat portion. As a result, the number of remanufacturing is increased and the cost is increased.

  In addition, the multilayer ceramic substrate is increasingly required to be smaller, thinner, and have higher functionality corresponding to higher density. For this reason, the number of layers of the multilayer ceramic substrate has increased, and it has been a problem to increase the cost further by producing molds according to the number of layers.

  Furthermore, the etching of the metal flat plate when producing the protrusions takes a long time to produce, and thus has been a problem for producing the multilayer ceramic substrate in a short time.

 Therefore, the present invention has been made in view of the above-described problems, and provides a sheet processing apparatus and a manufacturing method thereof that reduce manufacturing cost and manufacturing time while maintaining processing accuracy equivalent to that of a conventional mold. For the purpose.

  In order to solve the above problems, the sheet processing apparatus according to the present invention is characterized by a first mold having a plurality of protrusions on a first flat plate and a protrusion insertion hole into which the protrusion is inserted on the second flat plate. A ceramic green sheet is installed between the first mold and the second mold, and the protrusion penetrates the ceramic green sheet and is inserted into the protrusion insertion hole. A sheet processing apparatus for forming a plurality of holes in a ceramic green sheet, wherein the first flat plate is made of metal and the plurality of protrusions is made of resin.

  According to such a feature, the projection of the first mold can be formed with resin, so that the projection can be formed at a lower cost than the etching of the metal plate. In addition, the resin can be formed in a shorter time than the etching of the metal plate. Further, by forming the protrusion on the first flat plate made of metal, it is possible to suppress a decrease in the processing accuracy of the protrusion due to the influence of the shrinkage rate when the resin is cured. Accordingly, it is possible to obtain a sheet processing apparatus that reduces the manufacturing cost and the manufacturing time while maintaining the processing accuracy equivalent to that of the conventional mold.

  The gist of the sheet processing apparatus according to the present invention is that the resin is thermosetting.

 According to this feature, the adhesiveness with the first flat plate is further improved, the accuracy of the finished dimension with respect to the design value of the projection of the sheet processing apparatus is further improved, and the processing accuracy of the sheet processing apparatus can be further improved. . Moreover, since it hardens | cures immediately by applying heat, the sheet processing apparatus which can be produced in a further short time can be obtained.

  The gist of the sheet processing apparatus according to the present invention is that the bending strength of the resin is 50 MPa or more.

  According to such a feature, the strength of the protrusion using the resin can be further improved, and the durability as the sheet processing apparatus can be further improved.

 Further, the sheet processing apparatus according to the feature of the present invention is characterized in that the area of the cross section of the protrusion parallel to the plane of the first flat plate having the protrusion is from the lower surface of the protrusion in contact with the first flat plate to the upper surface of the protrusion. The main point is that it gradually decreases gradually.

 According to such a feature, the cross-sectional area of the protrusion in contact with the first flat plate decreases stepwise or gradually from the lower surface of the protrusion in contact with the first flat plate to the upper surface of the protrusion. When the resin is embedded and removed from the mold, the protrusion can be formed without breaking the shape of the protrusion. Thereby, the precision of the finished dimension with respect to the design value of the projection of the sheet processing apparatus can be further improved, and the processing accuracy of the sheet processing apparatus can be further improved. Further, for example, it becomes easy to form a through hole or the like in a sheet such as a ceramic green sheet. Further, since the shape is more stable, the durability is further improved.

  In order to solve the above-described problems, the method of manufacturing the sheet processing apparatus according to the present invention is characterized in that a first mold having a plurality of protrusions on the first flat plate and a plurality of protrusions inserted on the second flat plate. A ceramic green sheet is installed between the second mold having the protrusion insertion hole and the protrusion penetrates the ceramic green sheet and is inserted into the protrusion insertion hole, thereby forming a plurality of holes in the ceramic green sheet. A method for producing a sheet processing apparatus to be formed, comprising: a step of printing a resin on a first flat plate by a screen printing method to form a protrusion; and a step of curing the resin by heat. .

 According to this feature, protrusions can be formed at a lower cost than etching of a metal plate. Further, the protrusion formed of resin can be manufactured in a shorter time than etching of a metal plate.

 Also, if the protrusions are partially damaged, it is very difficult to recreate only the damaged protrusions with metal protrusions, but screen printing can be selectively formed, so it is easy to recreate only the damaged protrusions. Can be done.

 Curing time can be shortened by curing the resin with heat. According to this, it is possible to improve the accuracy of the shape of the protrusion formed of the resin.

 The gist of the method for producing a sheet processing apparatus according to the features of the present invention is that the viscosity of the resin in the step of forming the protrusion is 50 to 400 Pa · s.

 According to this feature, the workability during screen printing is further improved when the viscosity of the resin is 50 to 400 Pa · s. Thereby, a sheet processing apparatus can be produced in a shorter time.

 The gist of the method for producing a sheet processing apparatus according to the features of the present invention is that the curing shrinkage of the resin is 3% or less.

 According to this feature, since the shrinkage rate after curing is low, the accuracy of the finished dimension with respect to the design value of the projection of the sheet processing apparatus can be further improved, and the processing accuracy of the sheet processing apparatus can be further improved.

 ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the sheet processing apparatus and sheet processing apparatus which reduce manufacturing cost and manufacturing time can be provided, maintaining the processing precision equivalent to the conventional metal mold | die.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Sheet processing equipment]
Hereinafter, the sheet processing apparatus according to the present invention will be described. FIG. 1 is a cross-sectional view showing a manufacturing method in which through-hole processing is performed on a ceramic green sheet 21 using a sheet processing apparatus.

  As shown in FIG. 1A, the sheet processing apparatus includes a bottom mold 31 that is a first mold having a protrusion 11P formed of a resin on a metallic flat plate 2, and a protrusion into which the protrusion 11P is inserted. The upper mold 32 is a second mold having an insertion hole 32a. In the sheet processing apparatus, the ceramic green sheet 21 is installed between the bottom mold 31 and the upper mold 32.

  As shown in FIG. 1B, the sheet processing apparatus includes a ceramic green sheet 21 and a bottom mold 31 and an upper mold so that the protrusion 11P penetrates the ceramic green sheet 21 and is inserted into the protrusion insertion hole 32a. Clamp with the mold 32.

  As shown in FIG. 1C, a plurality of through holes 21a can be formed in the ceramic green sheet 21 by the processes of FIGS. 1A and 1B.

 The bottom mold 31 includes the flat plate 2 and the protrusions 11P. The flat plate 2 only needs to be a rigid metal. For example, stainless steel, copper, tungsten, aluminum, or the like can be used.

 The thickness of the flat plate 2 is not particularly limited, but is preferably 1 mm or more. According to this, the influence by the contraction rate of the protrusion 11P can be further suppressed.

 The protrusion 11P does not have a metal or the like that becomes a nucleus during formation on the flat plate 2, and is formed only of the resin 11. According to this, since the protrusion 11P can be formed on the flat plate 2 having nothing in one process, the sheet processing apparatus can be manufactured at low cost.

 The resin 11 is preferably a thermosetting resin. For example, an epoxy resin, a urea resin, a melamine resin, a phenol resin, an unsaturated polyester resin, an alkyd resin, or a urethane resin is preferable. A more preferable thermosetting resin is an epoxy resin, and according to this, the moldability at the time of embedding in a mold is further improved due to excellent adhesion and impregnation. In addition, since the epoxy resin has a low curing shrinkage rate, the accuracy of the finished dimension with respect to the design value of the protrusion can be further improved, and the processing accuracy of the sheet processing apparatus can be further improved. For example, Resin Kasei Co., Ltd. A-2426 etc. can be utilized as an epoxy resin.

  The bending strength of the resin 11 is preferably 50 MPa or more. According to this, the protrusion 11P having sufficient durability can be obtained. The bending strength of the resin 11 is more preferably 100 MPa or more.

As shown in the enlarged view of FIG. 2D, the protrusion 11P has a protrusion bottom surface width 11a on the flat plate 2 side and a protrusion upper surface width 11b on the opposite surface. The protrusion top face width 11b is preferably smaller than the protrusion bottom face width 11a. According to this, the cross-sectional area of the protrusion 11P in contact with the flat plate 2 is gradually or gradually increased from the lower surface of the protrusion in contact with the flat plate 2 to the upper surface of the protrusion. By reducing the size, the resin 11 is embedded in the mold along this shape, and the protrusion 11P can be formed without breaking the shape of the protrusion 11P when removed from the mold. Thereby, the precision of the finished dimension with respect to the design value of the protrusion 11P of the sheet processing apparatus can be further improved, and the processing accuracy of the sheet processing apparatus can be further improved. Further, it becomes easy to form the through hole 21a in the ceramic green sheet 21, and the shape is more stable, so that the durability is further improved. For example, the protrusion bottom face width 11a can be 210 μm, and the protrusion top face width 11b can be 150 μm. The protrusion 11P has a protrusion height 11c. This height depends on the thickness of the ceramic green sheet 21 forming the through hole 21a, but is preferably 50 to 220 μm or less. This makes it possible to process a generally used sheet having a thickness of 40 to 200 μm .

  The upper mold 32 has a protrusion insertion hole 32a. The width of the protrusion insertion hole 32a is preferably 50 to 100 μm larger than the width of the protrusion 11P, specifically, the protrusion bottom face width 11a. In the case of 50 μm or more, due to the difference in processing accuracy between the bottom mold 31 and the upper mold 32, the protrusion 11P can be accommodated in the protrusion insertion hole 32a even if the center of the protrusion 11P is shifted from the center of the protrusion insertion hole 32a. Can do. In the case of 100 μm or less, the through hole 21a can be accurately formed in the ceramic green sheet 21 by the protrusion 11P and the protrusion insertion hole 32a.

  Here, the first mold having the protrusion 11P is used for the bottom mold 31, and the second mold having the protrusion insertion hole 32a into which the protrusion 11P is inserted is used for the upper mold 32. However, the first mold having the protrusion 11P is used. The first mold may be the upper mold 32 and the second mold having the protrusion insertion holes 32a into which the protrusions 11P are inserted may be the bottom mold 31.

  According to the sheet processing apparatus according to the present invention described above, by forming the protrusion 11P of the bottom mold 31 with the resin 11, the protrusion 11P can be formed at a lower cost than etching of a metal plate. Further, the formation with the resin 11 can be made in a shorter time than the etching of the metal plate. By producing the protrusion 11P on the flat plate 2 made of metal, it is possible to suppress a decrease in the processing accuracy of the protrusion 11P due to the influence of the shrinkage rate when the resin 11 is cured. As a result, it is possible to obtain a sheet processing apparatus that can be manufactured in a short time while reducing the cost while maintaining the same processing accuracy as a conventional mold.

  For example, when the bottom mold 31 having the protrusion 11P having a diameter of 180 μm and a height of 80 to 100 μm is used, a through hole having a diameter of 180 to 200 μm can be formed in the ceramic green sheet 21 having a thickness of 50 μm. In addition, by using this sheet processing apparatus, it is possible to withstand use of 1000 times or more.

[Production method of sheet processing apparatus]
Hereinafter, the manufacturing method of the 1st type | mold which has the processus | protrusion 11P is demonstrated about the sheet processing apparatus which concerns on this invention. FIG. 2 is a cross-sectional view showing a first mold manufacturing method.

  As shown in FIG. 2A, a mold frame 1 having an opening pattern 1a formed at a position where the protrusion 11P is to be formed is produced. Although there is no restriction | limiting method in particular in the preparation methods of this opening pattern 1a of the metal mold | frame 1, For example, you may form in a thin metal plate with a laser processing machine and NC drill processing machine. Moreover, you may open the opening pattern 1a in a metal thin plate by an etching. Unlike the conventional half-etching of a mold, the drilling process by etching is a penetrating process, so that the process is very easy.

  The shape of the opening pattern 1a has a pattern in which a through hole 21a is formed in the ceramic green sheet 21, and as shown in the enlarged view of the protrusion 11P in FIG. And a protrusion 11P having a protrusion upper surface width 11b on the opposite surface. It is preferable to gradually or gradually decrease from the protrusion bottom face width 11a to the protrusion top face width 11b. For example, the cross section of the protrusion 11P may be trapezoidal or convex. When the cross section of the protrusion 11P is trapezoidal or convex, the cross section of the protrusion 11P is trapezoidal or convex with the lower side being the protrusion bottom surface width 11a and the upper side being the protrusion upper surface width 11b, and the lower side is longer than the upper side. According to this, it becomes easy to form the through hole 21a in the ceramic green sheet 21, and since the shape is more stable, the durability is further improved.

 As shown in FIG. 2B, after the mold frame 1 is installed on the flat plate 2 and the screen printing mask 3 and the mold frame 1 are aligned, the resin 11 is placed on the mold frame by the screen printing method. 1 is embedded in one opening pattern 1a to form a protrusion 11P.

  The flat plate 2 and the mold frame 1 are not bonded, but may be installed in a state where the standard of the mold frame 1 matches the standard of the flat plate 2. For example, the flat plate 2 and the mold frame 1 may be installed by an alignment pin or the like.

  Similarly, the screen printing mask 3 and the mold frame 1 can be aligned with each other using, for example, an alignment pin.

 Similar to the mold frame 1, the screen printing mask 3 is a metal thin plate having an opening pattern at a position where the protrusion 11P is to be formed. The screen printing mask 3 is supplemented with a paste containing the resin 11. Similarly to the mold frame 1, the screen printing mask 3 forms an opening pattern by a laser processing machine, NC drill, etching or the like.

  The squeegee 4 is made of rubber or the like, for example, and can move while being in close contact with the screen printing mask. Thereby, the paste containing the resin 11 flows from the opening pattern, and the paste containing the appropriate amount of the resin 11 can be embedded only at the position where the protrusion 11P is to be formed.

  Further, the viscosity of the paste containing the resin 11 is preferably 50 to 400 PaS when the protrusions 11P are formed. When the viscosity is within this range, workability during screen printing is further improved. Thereby, a sheet processing apparatus can be produced in a shorter time. The viscosity of the resin 11 is more preferably 100 to 300 PaS.

 As shown in FIG. 2C, the resin 11 embedded by the screen printing method is cured. Thus, the bottom mold 31 that is a mold having the protrusions 11P can be manufactured. The resin 11 is preferably a thermosetting resin 11. For example, an epoxy resin, a urea resin, a melamine resin, a phenol resin, an unsaturated polyester resin, an alkyd resin, or a urethane resin is preferable. A more preferable thermosetting resin is an epoxy resin, and according to this, the moldability at the time of pouring into a mold is further improved due to excellent adhesion and impregnation. In addition, since the epoxy resin has a low curing shrinkage rate, the shape of the protrusion 11P can be maintained without breaking the mold when removed from the mold. The accuracy of the finished dimension with respect to the design value of the protrusion can be further improved, and the processing accuracy of the sheet processing apparatus can be further improved.

  The cure shrinkage rate of the resin 11 is preferably 3% or less. According to this, since the shrinkage rate after curing is low, the accuracy of the finished dimension with respect to the design value of the projection of the sheet processing apparatus can be further improved, and the processing accuracy of the sheet processing apparatus can be further improved. Furthermore, the curing shrinkage rate of the resin 11 is preferably 2% or less.

 When the thermosetting epoxy resin 11 is used, the resin 11 can be cured by preheating at 80 to 100 ° C. for 1 to 3 hours and then holding at 110 to 140 ° C. for 1 to 2 hours. A more preferable curing temperature and time are to hold at 85 to 95 ° C. for 1 to 2 hours as preheating, and then to hold at 110 to 130 ° C. for 1 to 2 hours.

 After the heating and holding, the mold frame 1 is peeled to form the protrusions 11P to obtain the first mold as shown in FIG.

 According to the first mold manufacturing method of the sheet processing apparatus according to the present invention described above, the resin 11 is embedded in the mold frame 1 by the screen printing method, so that it is less expensive than etching of a conventional metal plate. The protrusion 11P can be formed.

 In addition, when the protrusion 11P is partially damaged, it is very difficult to recreate only the damaged protrusion with a conventional metal mold, but it can be selectively formed by screen printing. Remanufacturing can be easily performed. By curing the resin with heat, the curing time can be shortened. According to this, it is possible to improve the accuracy of the shape of the protrusion formed of the resin.

 The method of embedding the thermosetting resin 11 in the mold frame 1 by screen printing and curing it by thermosetting reduces the cost while maintaining the same processing accuracy as a conventional mold, and reduces the sheet in a short time. A processing apparatus can be manufactured.

  For example, when epoxy resin is used with the thickness of the mold frame 1 being 100 μm and the minimum diameter of the opening pattern 1a being 180 μm, preheating is held at 90 ° C. for 2 hours, and then heated and cured at 120 ° C. for 1 hour. A bottom mold 31 having a protrusion 11P having a diameter of 180 μm and a height of 80 to 100 μm can be produced. When this sheet processing machine is used, a through hole having a diameter of 180 to 200 μm can be formed in the ceramic green sheet 21 having a thickness of 50 μm.

[Multilayer ceramic substrate]
A method for producing a multilayer ceramic substrate produced by the sheet processing apparatus according to the present invention will be described. FIG. 3 is a schematic view showing a method for producing a multilayer ceramic substrate. The sheet processing apparatus according to the present invention is used in a process of providing a through hole 21a in the ceramic green sheet 21 shown in FIG.

  As shown in FIG. 3A, a ceramic green sheet 21 such as glass ceramic is cut into a predetermined shape and processed into a sheet. The ceramic green sheet 21 may be attached to a film such as PET, for example, in order to improve the convenience of handling.

  As shown in FIG. 3B, a through hole 21a having a predetermined shape is processed at a predetermined position. The through hole 21a is formed by the process of FIGS. 1A to 1C using the sheet processing apparatus of the present invention.

  As shown in FIG. 3C, a through-hole paste 22 that secures conduction between the stacked green sheets 21 is printed so as to fill the through-hole 21a. The through-hole paste 22 is composed mainly of a metal in order to ensure conduction. Specifically, silver, copper or the like is used as the main component. The through-hole paste 22 is embedded at the position of the through-hole using a printing mask by a screen printing method or the like.

  Next, the wiring pattern paste 23 is printed. Similar to the through-hole paste 22, the wiring pattern paste 23 is composed mainly of metal in order to ensure electrical continuity on the ceramic green sheet 21. Specifically, silver, copper or the like is used as the main component. The wiring pattern paste 23 is printed at a predetermined position on the ceramic green sheet 21 by a screen printing method or the like using a printing mask so that the L component (inductance) and the C component (capacitance) can be incorporated. .

 As shown in FIG. 3D, the green sheet laminate 24 is produced by laminating the ceramic green sheets 21 on which the through-hole paste 22 and the wiring pattern paste 23 are printed layer by layer. The green sheet laminate 24 includes the ceramic green sheets 21 according to the number of layers to be laminated. Here, the green sheets 24A, 24B, 24C and the like are set according to the order of the layers.

  The green sheet laminate 24 may be a laminate by applying pressure or heat to a plurality of constituent green sheets 24A and the like at once. Alternatively, the green sheets 24A and the green sheets 24B may be laminated first, and then the green sheets 24C may be laminated one by one.

  Next, the green sheet laminate 24 is fired. In firing, for example, by holding at 900 ° C., the green sheet laminate 24 is sintered to obtain a ceramic laminate.

  As shown in FIG. 3E, the multilayer ceramic substrate 25 is obtained by cutting and dividing the ceramic multilayer body for each element.

 Alternatively, the multilayer ceramic substrate 25 may be obtained by firing the green sheet laminate 24 after cutting and dividing.

  According to the multilayer ceramic substrate 25 described above, an L component (inductance) and a C component (capacitance) can be incorporated according to the wiring pattern. As a result, the number of inductors and capacitors mounted on the multilayer ceramic substrate 25 is reduced, and the high-frequency circuit module is reduced in size.

  Although the through hole 21a can be formed by laser processing or the like, in many cases, batch processing is performed by a mold from the processing time required for the ceramic green sheet 21 and the manufacturing cost.

It is typical process sectional drawing which shows the flow of the through-hole process by the sheet processing apparatus which concerns on this invention. It is typical process sectional drawing which shows the manufacturing method flow of the 1st type | mold which has protrusion of the sheet processing apparatus which concerns on this invention. It is a schematic diagram which shows the preparation flow of the laminated ceramic substrate processed by the sheet processing apparatus which concerns on this invention. It is typical process sectional drawing which shows the flow of the manufacturing method of the metal mold | die which has protrusion of the conventional sheet processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mold frame, 1a ... Opening pattern, 2 ... Flat plate, 2P ... Projection, 3 ... Screen printing mask,
4 ... Squeegee, 5 ... Photoresist, 6 ... Exposure mask, 6a ... Exposure pattern, 11 ... Resin,
11P ... protrusion, 11a ... projection bottom surface width, 11b ... projection top surface width, 21 ... ceramic green sheet,
21a ... through hole, 22 ... through hole paste, 23 ... wiring pattern paste,
24 ... Green sheet laminate, 25 ... Multilayer ceramic substrate, 31 ... Bottom mold,
32 ... Upper mold, 32a ... Projection insertion hole, 33 ... Mold

Claims (7)

A first mold having a plurality of protrusions on a first flat plate; and a second mold having a protrusion insertion hole into which the protrusion is inserted on a second flat plate, the first mold, A sheet processing apparatus in which a ceramic green sheet is installed between the second mold and the protrusion penetrates the ceramic green sheet and is inserted into the protrusion insertion hole to form a plurality of holes in the ceramic green sheet. There,
The sheet processing apparatus, wherein the first flat plate is made of metal, and the plurality of protrusions are made of resin.   The sheet processing apparatus according to claim 1, wherein the resin is thermosetting.   The sheet processing apparatus according to claim 1 or 2, wherein the bending strength of the resin is 50 MPa or more.   The area of the cross section of the protrusion parallel to the plane of the first flat plate having the protrusion is gradually or gradually decreased from the lower surface of the protrusion in contact with the first flat plate to the upper surface of the protrusion. The sheet processing apparatus according to any one of claims 1 to 3. A ceramic green sheet is installed between a first die having a plurality of protrusions on the first flat plate and a second die having a protrusion insertion hole into which the plurality of protrusions are inserted on the second flat plate. The method for producing a sheet processing apparatus for forming a plurality of holes in the ceramic green sheet by inserting the protrusions through the ceramic green sheet and inserting into the protrusion insertion holes,
On the first flat plate, a step of installing a mold frame in which an opening pattern is formed at a position where the protrusion is formed and a screen printing mask in this order;
Forming the protrusions by embedding a resin in the opening pattern of the mold frame by a screen printing method;
And a step of curing the resin by heat.   The method for producing a sheet processing apparatus according to claim 5, wherein the resin has a viscosity of 50 to 400 Pa · s in the step of forming the protrusions.   The method for producing a sheet processing apparatus according to claim 5 or 6, wherein a curing shrinkage rate of the resin is 3% or less.

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