JPH1158915A - Impression cylinder of screen printing machine and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight impression cylinder of a screen printing machine capable of being produced at a low cost and a method for producing the same. SOLUTION: An impression cylinder 10 of a screen printing machine rotated while pressing the paper fed by a paper feed means to a plate cylinder rotated in such a state that a master after plate making is mounted on the outer peripheral surface of the plate cylinder has a cylindrical member 40 comprising a thermosetting synthetic resin and the rubber layer 50 integrally molded on the outer peripheral surface of the cylindrical member 40 and having a surface finished by grinding processing. Further, the cylindrical member 40 is formed into a cup shape having a bottom plate at one end thereof and a disc-shaped flange 41 is fixed to the other end of the cylindrical member 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an impression cylinder for a stencil printing machine and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a stencil printing apparatus, a cylindrical plate cylinder which rotates with a pre-made master mounted on the outer peripheral surface, and a sheet conveyed one by one by a paper feeding means are rotated while being pressed against the plate cylinder. There is known a printer having a cylindrical impression cylinder that performs printing by transferring ink from an ink supply unit to paper in this pressed state.

The impression cylinder has substantially the same diameter as the plate cylinder, is driven to rotate at the same rotation speed as that of the plate cylinder, and has a recess extending in the generatrix direction on a part of its outer peripheral surface. I have. The concave portion is provided with a clamp means for clamping the leading edge of the sheet. According to such an impression cylinder, the amount of movement of the impression cylinder when pressing the impression cylinder against the plate cylinder can be reduced by making the position of the concave portion correspond to the position of the master clamper of the plate cylinder. The printing pressure sound at the time can be reduced. Further, since the sheet is conveyed by clamping the leading end of the sheet by the clamp means, it is possible to prevent the sheet from winding up at the time of sheet ejection and to improve registration accuracy.

As shown in FIG. 10, as an impression cylinder 100, an extruded aluminum material 102 formed so as to have a cross-sectional shape lacking a part of the circumference is used. It is known that a rubber layer 104 is formed on a surface and an outer peripheral surface of the rubber layer 104 is ground. A cross-shaped rib 103 is formed inside the extruded material 102 to secure strength.
A shaft 101 is provided at the center of the two, that is, at the portion where the ribs 103 intersect. There is also known an aluminum extruded material that is cut, and the outer peripheral surface thereof is subjected to grinding processing before use.

[0005]

When an extruded aluminum material is used for the impression cylinder, it is difficult to reduce its thickness due to its manufacturing properties. Since multiple ribs are required inside the torso,
There is a problem that the impression cylinder is heavy. If the impression cylinder is heavy, its rotational inertia becomes large, and a large driving torque is required during rotation.

It is conceivable to reduce the weight of the impression cylinder by reducing the number of ribs. In this case, however, the strength of the impression cylinder is reduced, and a rubber layer is formed on the outer peripheral surface of the impression cylinder by rubber molding. When it is provided, the outer peripheral portion of the impression cylinder may be depressed inward and deformed by the rubber molding pressure. In addition, since an extruded aluminum material is used, there is also a problem that the manufacturing cost is high. Furthermore, on a part of the outer peripheral surface of the impression cylinder,
In the case where a concave portion for attaching the paper clamper extending in the generatrix direction is provided, the cross section of the impression cylinder is not a perfect circle, so that it is difficult to secure dimensional accuracy during extrusion processing. The cost is high.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an impression cylinder for a stencil printing apparatus which can be manufactured at a low cost at a low cost, and a method of manufacturing the same.

[0008]

According to the first aspect of the present invention,
In the impression cylinder of the stencil printing machine, which rotates while pressing the sheet fed by the sheet feeding means onto the rotating plate cylinder with the prepressed master mounted on the outer peripheral surface, a cylindrical body made of a thermosetting synthetic resin. , Which is integrally formed on the outer peripheral surface of the cylindrical body, and has a rubber layer whose surface is finished by grinding.

According to a second aspect of the present invention, in the stencil printing machine of the first aspect, the cylindrical body has a cup shape having a bottom plate at one end, and a disc-shaped flange is fixed to the other end of the cylindrical body. Configuration.

[0010] The third aspect of the present invention is the first or second aspect.
In the impression cylinder of the stencil printing apparatus described above, a sheet made of a synthetic resin film is wound around an outer peripheral surface of a rubber layer.

According to a fourth aspect of the present invention, there is provided an impression cylinder for a stencil printing machine according to the first, second, or third aspect, wherein a paper clamp for extending in the direction of the generatrix is provided on a part of the outer peripheral surface of the cylindrical body. In this configuration, a concave portion is provided, and a rubber layer is also provided in the concave portion.

[0012] The invention according to claim 5 is the invention according to claims 1, 2, 3, and 4.
Or, in the impression cylinder of the stencil printing machine described in 4, the respective outer diameters of the predetermined areas at both ends of the cylinder gradually increase from the center to the end of the cylinder, respectively. The thickness of the rubber layer is gradually reduced from the center to the end of the cylindrical body.

[0013] The invention according to claim 6 is the invention according to claims 1, 2, and 3.
3. The impression cylinder of a stencil printing machine according to 3, 4 or 5, wherein when the impression cylinder is pressed against the plate cylinder, the thickness of a portion of the rubber layer that first comes into contact with the plate cylinder is changed to a thickness of another portion of the rubber layer. This is a configuration that is thicker than the thickness.

According to a seventh aspect of the present invention, there is provided a method for manufacturing an impression cylinder of a stencil printing machine which rotates while pressing a sheet fed by a sheet supply means onto a rotating plate cylinder with a master made on a peripheral surface. In a method, a cup-shaped cylinder having a bottom plate at one end is integrally molded with a thermosetting synthetic resin, and a disc-shaped flange made of a synthetic resin is adhered and fixed to the other end of the cylinder, and the bottom plate and A support shaft is inserted through each center of the flange, a rubber layer is provided on the outer peripheral surface of the cylindrical body by integral molding, and the outer peripheral surface of the rubber layer is finished by grinding.

According to an eighth aspect of the present invention, in the method for manufacturing an impression cylinder according to the seventh aspect, the outer peripheral surface of the rubber layer is subjected to a surface treatment for reducing the coefficient of friction and improving the non-adhesiveness.

[0016]

An embodiment of the present invention will be described with reference to the drawings.
First, a stencil printing apparatus using the impression cylinder of the present invention will be described. As shown in FIG. 1, the plate cylinder 1 has a cylindrical body having a porous structure, and is configured by winding a mesh screen around the outer peripheral surface of the cylindrical body. A master clamper 2 that is rotatable parallel to the axis of the plate cylinder 1 is provided on an outer peripheral portion of the plate cylinder 1. The master clamper 2 is opened and closed at a predetermined position by transmitting a driving force by an opening / closing device (not shown). One end of the master 3 is clamped by the master clamper 2. The other end of the master 3 is wound around the outer peripheral surface of the plate cylinder 1.

The master 3 is pierced by a thermal head in a plate making / writing device (not shown) based on the information of the document, and is then sent out to the plate cylinder 1 and wound around the plate cylinder 1. The used master 3 already wound around the plate cylinder 1 is separated from the plate cylinder 1 and stored in a plate discharging device (not shown).

The plate cylinder 1 is rotated clockwise by a driving device (not shown) (the direction of arrow A in the figure). Plate cylinder 1
Inside, an ink roller 4 that rotates in synchronization with the plate cylinder 1 in the same direction, and a doctor roller 5 that is arranged with a slight gap from the outer peripheral surface of the ink roller 4 are arranged. . The rollers 4 and 5 supply the ink in the ink pool 6 to the outer peripheral surface of the ink roller 4. The ink is
The ink is supplied from a hole in the shaft pipe 7 to the ink reservoir 6 in the wedge-shaped space. Further, the ink supplied to the outer peripheral surface of the ink roller 4 is supplied to the inner peripheral surface of the plate cylinder 1 because there is a slight gap between the inner peripheral surface of the plate cylinder 1 and the outer peripheral surface of the ink roller 4. .

Below the plate cylinder 1, an impression cylinder 10 pressed against the plate cylinder 1 is provided so as to face the ink roller 4. The impression cylinder 10 includes a main body 40 which is a main part of the impression cylinder 10.
And a shaft 11 for supporting the impression cylinder 10 and a rubber layer 50 provided on the outer peripheral surface of the main body 40. The main body 40 and the rubber layer 50 will be described later in detail.

A part of the outer peripheral surface of the impression cylinder 10 is formed with a concave portion 17 extending in the generatrix direction of the impression cylinder 10 in order to avoid collision with the master clamper 2 on the plate cylinder 1. The recess 17 is provided with a clamper base 18 made of a synthetic resin, and a paper clamper 19 for holding the leading end of the paper P on the impression cylinder 10 is attached to the clamper base 18. The paper clamper 19 is rotatably supported by a shaft 19a. The paper clamper 19 is opened at a predetermined timing by a cam (not shown).
And when the sheet reaches the position of the peeling claw 20, the sheet is opened again, and the sheet P
Is released, and the sheet P is sent to the sheet discharging and conveying device 21.

The impression cylinder 10 is connected by an endless belt so that the pressing position against the plate cylinder 1 becomes the same every rotation, and rotates in a counterclockwise direction (the direction of arrow B in the figure). It has become.

The shaft 11 of the impression cylinder 10 is supported by a pair of arms 13 (only one of which is shown) that can swing about a fulcrum shaft 12. It is freely movable toward and away from the plate cylinder 1. The free end of the arm 13 is constantly urged by a spring 14 having one end fixed to a side plate of the apparatus so that the impression cylinder 10 presses the plate cylinder 1. A cam follower 15 is provided at a free end of the arm 13. The cam follower 15 controls a swing of the arm 13, that is, a printing pressure cam for controlling pressing of the impression cylinder 10 against the plate cylinder 1. 16 abuts.

The impression cylinder 10 is provided with a printing pressure cam 16 which rotates in synchronization with the plate cylinder 1 so as to prevent the impression cylinder 10 from being pressed against the plate cylinder 1 during plate making, as a countermeasure in the case of poor conveyance of the paper P.
As a result, it is separated from the plate cylinder 1 at a predetermined timing. If there is no conveyance failure, the impression cylinder 10 holding the sheet P is pressed against the outer peripheral surface of the plate cylinder 1 by the spring 14 again. When a transport failure occurs, the impression cylinder 10 is not pressed against the plate cylinder 1 and is released by a printing pressure release device (not shown).

In FIG. 1, an elevator type paper feed tray 30 capable of stacking a large number of sheets P is provided at the lower right of the plate cylinder 1 in the figure, and the impression cylinder 10 is rotated in the direction of arrow C in the figure. And a pair of upper and lower feed rollers 31 for feeding paper P
Are provided. The paper feed tray 30 moves up and down while maintaining a state in which the highest position of the stacked papers P is always in contact with the paper feed rollers 32 with a pressing force within a proper range, that is, a range in which the papers P can be transported.

The paper feed tray 30 and the feed rollers 31, 3
A separation roller 33 that feeds the paper P from the paper feed tray 30 to the feed rollers 31, 31 is provided between the feed roller 31 and the feed roller 31. Below the separation roller 33, a separation pad 34 for preventing double feeding of sheets is provided. The paper feed roller 32 is separated from the separation roller 33 in the direction of arrow D in FIG.
Rotate in the direction of arrow E in the figure. The paper feed tray 30, the feed rollers 31, 31, the paper feed roller 32, and the separation roller 33 constitute a paper feed unit.

At the lower left of the plate cylinder 1 in the figure, a peeling claw 20 for peeling the paper P after printing (after ink application) from the impression cylinder 10, and transporting the peeled paper P to a paper discharge tray 22. And a paper discharge tray 22 that stores the paper P transported by the paper discharge transport device 21. The paper discharge conveyance device 21 includes a suction fan 23 that suctions the back surface of the paper P, and a pair of conveyance rollers 24 and 25.
And a belt 26 stretched between the transport rollers 24 and 25.

Next, the printing operation of the above-described stencil printing apparatus will be described. In FIG. 1, the paper P fed by the rotation of the paper feed roller 32 is prevented from being double fed by the separation roller 33 and the separation pad 34, and only the top sheet is fed to the feed rollers 31, 31. Can be When the leading end of the paper P is transported between the feed rollers 31, 31, the paper P is transported by the feed rollers 31 toward the impression cylinder 10. In accordance with this timing, the impression cylinder 10
The paper clamper 19 inside is opened, and after the paper P is added, the paper clamper 19 is closed, and while the paper P is held by the impression cylinder 10, the impression cylinder 10 rotates, and the nip between the plate cylinder 1 and the impression cylinder 10 is rotated. The sheet P is sent to the unit.

In FIG. 1, the nip portion between the plate cylinder 1 and the impression cylinder 10 is pressurized by the force of a spring 14, and the sheet P is pressed against the outer peripheral surface of the plate cylinder 1. During this pressing,
The ink that has passed through the perforated portion of the master 3 attached to the outer peripheral surface of the plate cylinder 1 is transferred by the ink roller 4, and printing is performed.

The paper P on which the ink has been transferred is further rotated by the impression cylinder 10, whereby the paper clamper 19 opens before the peeling claw 20 and is peeled off by the peeling claw 20. 22 and is stacked on the paper discharge tray 22 to complete the printing.

Next, a first embodiment according to the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 2 and 3, the main body 40 has a bottom plate 40 at one end.
It consists of a bottomed cylinder having a, that is, a cup-shaped cylinder. The other end of the main body 40 has a disc-shaped flange 41.
Are fixed by bonding. The main body 40 and the flange 41 are integrally formed of a thermosetting synthetic resin, for example, a phenol resin. Thermosetting synthetic resin is a resin that loses plasticity when heated and changes into a rigid body.It has a smaller coefficient of thermal expansion than thermoplastic synthetic resin, and can be molded with high strength and thick wall, and deforms. It has the characteristic of being difficult.

By integrally molding the main body 40 with a thermosetting synthetic resin, there is no need to provide ribs inside the main body 40, and the impression cylinder 10 can be formed more easily than when a conventional aluminum extruded material is used. The weight can be reduced.
Also, it is stiffer and less thermally deformed than conventional extruded aluminum. Further, the strength of the impression cylinder 10 can be improved by forming the main body 40 as a cup-shaped cylindrical body and fixing the flange 41 to the opening end.

The shaft 11 is inserted through each center of the bottom plate 40a and the flange 41. The shaft 11 is fixed to the bottom plate 40a by pins 42. Ball bearings 43 and 43 are press-fitted into respective portions of the shaft 11 protruding from both ends of the impression cylinder 10, that is, portions protruding from the bottom plate 40 a and the flange 41. , A gear 44 is fixedly provided. Ball bearings 43, 43
Is fixed to the arm 13 so that the impression cylinder 1
0 is rotatably supported by the arm 13. Gear 4
The endless belt 4 meshes with the endless belt 4.

The rubber layer 50 is provided on the peripheral surface of the main body 40 other than the recess 17, that is, on an arc-shaped portion. At the boundary between the concave portion 17 and the arc-shaped portion, the end surface 50a of the rubber layer 50 is substantially flush with the edge surface 17a of the concave portion 17, as shown in FIG.

As shown in FIG. 5, the rubber layer 50 has two rubber layers, a nitrile rubber layer 51 in contact with the outer peripheral surface of the main body 40, and a silicon rubber layer 52 covering the outer peripheral surface of the nitrile rubber layer 51. It is composed of Nitrile rubber layer 51
Is integrally rubber-molded on the outer peripheral surface of the main body 40 and is adhered to the outer peripheral surface of the main body 40. Silicon rubber layer 5
2 is a method in which a liquid silicone rubber is sprayed on the outer peripheral surface of the nitrile rubber layer 51 to form a coating film, and then the outer diameter of the coating film has the same outer diameter of the impression cylinder 10 as the outer diameter of the plate cylinder 1. It is formed by grinding. By grinding the outer peripheral surface, the outer diameter dimensional accuracy and the outer peripheral surface accuracy of the impression cylinder 10 can be finished with high accuracy.

In this embodiment, the silicon rubber layer 52
The outer peripheral surface of the nitrile rubber layer 51 is ground because the outer peripheral surface of the nitrile rubber layer 51 is not required because the outer peripheral surface of the nitrile rubber layer 51 is ground. Not. Therefore, the rubber layers 51, 5
Of the two, a portion to be attached to the outermost peripheral surface of the impression cylinder 10 is formed at least by integral molding and is ground.

Since the nitrile rubber layer 51 is integrally formed of rubber on the outer peripheral surface of the main body 40, the nitrile rubber layer 5
1 strongly adheres to the main body 40, and the separation of the nitrile rubber layer 51 from the main body 40 can be prevented.

Further, by forming the outer peripheral surface of the impression cylinder 10 with the silicone rubber layer 52, it is possible to prevent ink adhering to the outer peripheral surface of the impression cylinder 10 from being wiped and prevent paper powder from adhering. This is because when the outer peripheral surface of the silicon rubber layer 52 is ground, the processed surface of the silicon rubber becomes less adhesive than the processed surface of the nitrile rubber. Therefore, it is considered that the rubber layer 50 is composed only of the silicon rubber layer 52. However, the silicone rubber has low adhesiveness to the resin, that is, the main body 40, and the main body 40 and the silicon rubber layer 52
However, there is a problem in that it is difficult to integrally mold with the above, and the manufacturing cost increases. Therefore, in this embodiment, the silicone rubber layer 52 is formed on the outer peripheral surface of the impression cylinder 10.

As shown in FIGS. 2 and 5, on the outer peripheral surface between the bottom plate 40a and the open end 40b of the main body 40, a tapered portion whose outer diameter gradually increases from the center to the end of the main body 40. 40c are provided respectively. The nitrile rubber layer 51 corresponding to the tapered portion 40c has a tapered portion 4
Contrary to 0c, the thickness gradually decreases from the center of the main body 40 toward the end. In other words, the outer peripheral surface of the nitrile rubber layer 51 is a smooth peripheral surface with no irregularities.

Therefore, since the thickness of both ends of the main body 40 is larger than the thickness of the center of the main body 40, the rigidity of the end of the main body 40 is improved. At the time of printing, particularly at the time of low temperature or high-speed printing, the rigidity of both ends of the impression cylinder 10 is insufficient, and both ends of the impression cylinder 10 are deformed, the printing pressure is reduced, and both ends in the width direction of the paper P are Although a problem such as blurring or loss of an image occurs, by improving the rigidity of both ends of the impression cylinder 10 as described above, printing pressure is secured over the entire image area, and blurring or loss of the image can be prevented. .

Referring to FIG. 5, the thickness and length of each part will be described. In this embodiment, the thickness t1 of the main body part 40 is 3 to 5 mm. The thickness t2 of the portion of the nitrile rubber layer 51 corresponding to the center of the main body 40 is 3 to 6 mm, whereas the thickness t3 of the portion of the nitrile rubber layer 51 corresponding to the end of the main body 40 is 1 ２2 mm. At this time, the length L of the tapered portion 40c of the main body 40 is 30 to 50 mm.
It is. The silicon rubber layer 52 is substantially uniform over the entire circumference of the impression cylinder 10, and has a thickness t4 of about 0.5 mm.

Next, a method for manufacturing the impression cylinder 10 will be described. The molding die for molding the main body 40 having the above-described shape is constituted by a pair of dies. In FIG. 3, when the main body 40 is divided by the parting line PL,
A mold for molding the main body 40 on the side including the concave portion 17 (the portion above the parting line PL in the figure), and the main body 40 on the side not including the concave portion 17 (parting line PL in the figure) Lower part). The parting line PL is the impression cylinder 1
The plane passes through the center of 0 and divides the impression cylinder 10 in the generatrix direction.

A thermosetting synthetic resin, for example, a phenol resin is put in a pair of molds, and heated and pressed. Due to this heating and pressure, the phenol resin loses its plasticity and hardens, and the body 4 is a cup-shaped cylindrical body.
It becomes a molded article as 0. Further, in a separate step, similarly to the main body 40, the flange 41 is also integrally formed of phenol resin. Molded main body 40 and flange 4
1 are fixed to each other. That is, the disk-shaped flange 41 is fixed to the opening end 40b of the main body 40 by bonding, so that a columnar body is formed.

In the cylindrical main body 40, the shaft 1
1 is inserted into each center of the bottom plate 40a and the flange 41. After the shaft 11 is inserted, the shaft 11 is
fixed to a. A ball bearing 43 is press-fitted into a portion of the shaft 11 protruding from the bottom plate 40a, and a gear 44 is provided. A ball bearing 43 is press-fitted into a portion of the shaft 11 protruding from the flange 41.

Next, nitrile rubber is integrally formed on the outer peripheral surface of the main body 40 by rubber molding, and a nitrile rubber layer 51 is formed on the outer peripheral surface of the main body 40. Thereafter, liquid silicon rubber is uniformly sprayed on the outer peripheral surface of the nitrile rubber layer 51 so that the thickness thereof becomes approximately 0.5 mm, and a coating film of the silicon rubber is formed on the outer peripheral surface. Layer 52 is formed.

After the silicon rubber layer 52 is formed on the outer peripheral surface of the nitrile rubber layer 51, the impression cylinder 10 is rotated while supporting the shaft 11, and the outer peripheral surface of the silicon rubber layer 52 is ground using a cylindrical grinder. Process. By this grinding, the outer diameter of the impression cylinder 10 is finished to be the same as the outer diameter of the plate cylinder 1. The dimensional accuracy of the outer diameter at this time is ± 0.05mm ~
Finished with accuracy within ± 0.1mm.

Here, the grinding of the outer peripheral surface of the silicon rubber layer 52 will be described.
0 is made to be the same as the outer diameter of the plate cylinder 1. In this embodiment, in addition to obtaining this outer diameter accuracy, the outer peripheral surface of the silicone rubber layer 52 is simultaneously placed in a low tack state. Finished. The term "adhesiveness" as used herein refers to a property of slightly sticky, a state in which paper dust easily adheres, and a state in which the leading end of the paper is hard to slip.

The outer peripheral surface sprayed with silicone rubber has a little roughness and a slightly sticky property.
That is, it is sticky. By grinding the outer peripheral surface, the outer peripheral surface is roughened, the tackiness is reduced, the outer peripheral surface is changed to a smooth property, and the outer peripheral surface is in a low tackiness state.

Next, a second embodiment of the present invention will be described. In the stencil printing machine of the first embodiment, when the impression cylinder 10 is pressed against the plate cylinder 1 during printing, a large pressing force is applied to a portion of the rubber layer 50 that first comes into contact with the plate cylinder 1. . This pressing force causes the impression cylinder 1
0 may bounce with the plate cylinder 1, and when this bounce occurs, there is a problem that a white spot occurs at the leading end of the image. As shown in FIG. 6, the white spot at the tip of the image refers to a phenomenon in which the image is lost at the portion where the impression cylinder 10 bounds immediately after pressing. In FIG. 6, reference symbol P denotes a sheet, reference symbol N denotes a solid print image (portion indicated by hatching), reference symbol M denotes a missing image portion, and arrow S denotes a sheet P.
Are shown, respectively.

Therefore, in the second embodiment, in the stencil printing machine described in the first embodiment, when the impression cylinder 10 is pressed against the plate cylinder 1, the rubber layer 50 first contacts the plate cylinder 1. The thickness of the portion to be formed is larger than the thickness of the other rubber layers 50. The details will be described below. As shown in FIG. 7, the end 50 b of the rubber layer 50 is formed so as to enter the inside of the recess 17. As described above, by providing the rubber layer 50 not only in the arc portion of the main body 40 but also in the concave portion 17, the rubber layer 50 does not easily come off from the main body 40, and the adhesion between the main body 40 and the rubber layer 50 is insufficient. Peeling can be prevented. Further, the rubber layer 50 may be adhered to the entire surface of the concave portion 17.

When the impression cylinder 10 is pressed against the plate cylinder 1, the portion of the impression cylinder 10 that first comes into contact with the plate cylinder 1 is a step on the upstream side of the concave portion 17 in the rotation direction of the impression cylinder 10, that is, This is a step on the side where the clamper base 18 is provided. The step portion is provided with a flat portion 17b having a flat surface. The flat portion 17b is covered with the rubber layer 50,
A thick portion 50b is provided in a portion corresponding to the flat portion 17b so that the outer peripheral surface of the portion maintains an arc shape. The thickness of the thick portion 50b is larger than the thickness of the other rubber layers 50.

Therefore, when the impression cylinder 10 is pressed against the plate cylinder 1 and the impact due to the pressing force is absorbed by the thick portion 50b, the amount of impact absorption can be increased, and the gap between the impression cylinder 10 and the plate cylinder 1 can be increased. And the occurrence of white spots at the leading end of the image can be prevented. In addition, the printing pressure noise can be reduced.

In the stencil printing apparatus, at the time of printing, the leading end of the paper P is conveyed toward the paper clamper 19, and at this time, the leading end of the paper P is placed on the outer peripheral surface of the impression cylinder 10, that is, the rubber layer 50. Will be fed while sliding on the outer peripheral surface of. At this time, if the outer peripheral surface of the rubber layer 50 is formed of nitrile rubber, since the coefficient of friction is large, there is a problem that the paper P slips and is easily caught.

When the plate making area is larger than the sheet size, the ink from the plate cylinder 1 may adhere to the outer peripheral surface of the impression cylinder 10. In this case, it is necessary to clean the surface of the impression cylinder 10, but if the outer peripheral surface of the rubber layer 50 is formed of nitrile rubber, there is a problem that it is difficult to wipe off the ink.

Further, when the outer peripheral surface of the rubber layer 50 is formed of nitrile rubber, paper powder easily adheres to this outer peripheral surface. When paper dust adheres and accumulates, there is also a problem that image defects such as density unevenness occur in the image at that portion.

Therefore, in order to solve these problems,
As described in the first embodiment, by forming the outer peripheral surface of the rubber layer 50 with the silicon rubber layer 52,
There is a method for wiping the ink adhered to the outer peripheral surface of the paper and preventing adhesion of paper powder. As another method, there is a method described in claims 3 and 8.

First, a third embodiment of the present invention will be described. The impression cylinder 10 of the third embodiment includes:
Since the configuration is substantially the same as that of the impression cylinder 10 described in the second embodiment, the same members as those shown in FIG. 7 are denoted by the same reference numerals as those used in FIG. The differences will be described.

As shown in FIG. 8, the rubber layer 50 is made of only nitrile rubber having elasticity. As described in the first embodiment, the nitrile rubber is formed by molding the main body 4 by rubber molding.
0 is provided. The outer peripheral surface of the rubber layer 50 is ground and finished so that the outer diameter of the impression cylinder 10 is the same as the outer diameter of the plate cylinder 1. A polyester sheet 55 as a synthetic resin film having a thickness of 50 to 200 μm is wound around the outer peripheral surface of the finished rubber layer 50.

The polyester sheet 55 is adhered to the outer peripheral surface of the nitrile rubber layer 51 by a well-known adhesive.
Therefore, the impression cylinder 10 is formed by the polyester sheet 55.
Has low friction and non-adhesiveness, which makes it possible to improve the wiping properties of the ink at the time of ink adhesion and to prevent the adhesion of paper dust.

The polyester sheet 55 may be attached to the outer peripheral surface of the rubber layer 50 using a double-sided adhesive tape.
Also, by setting the adhesive strength of this double-sided adhesive tape to weak,
If it can be attached and peeled, the polyester sheet 55
It is also possible to replace only and re-paste.

Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the rubber layer 5
No. 0 is subjected to surface treatment to transform the outer peripheral surface into a low friction and non-adhesive property. The details will be described below.

As shown in FIG. 9, the rubber layer 50 is made of only nitrile rubber having elasticity. As described in the first embodiment, the nitrile rubber is formed by molding the main body 4 by rubber molding.
0 is provided. The outer peripheral surface of the rubber layer 50 is ground and finished so that the outer diameter of the impression cylinder 10 is the same as the outer diameter of the plate cylinder 1. The outer peripheral surface of the rubber layer 50 is subjected to a surface treatment called a halogenation treatment.

The halogenation treatment is well known as a treatment method for a wiper blade of a vehicle, is a kind of a modification treatment of a rubber surface layer, and is mainly a chlorination treatment. In the present embodiment, a commercially available aftertreating solution is applied and dried as the halogenation treatment. By applying a halogenation treatment to the outer peripheral surface of the rubber layer 50, the rubber layer 5 is formed.
0 is chlorinated, and a hardened layer 56 of several microns to several tens of microns is formed on this outer peripheral surface. Normally, fine cracks (not shown) are generated in the cured layer 56. The hardened layer 56 reduces the coefficient of friction of the outer peripheral surface of the rubber layer 50 and improves the roughness of the outer peripheral surface.

Accordingly, the properties of the outer peripheral surface of the rubber layer 50 become low friction and non-adhesive, so that the wiping property of ink at the time of ink adhesion can be improved, and the adhesion of paper powder can be prevented. . Further, instead of the above-described halogenation treatment, a fluororesin-based low-temperature treatment film may be applied and formed on the outer peripheral surface of the rubber layer 50.

In the first to fourth embodiments described above, the impression cylinder 10 has a disk-shaped flange fixed to the open end of a cup-shaped cylinder. However, the present invention is not limited to this.
For example, the impression cylinder may be configured by fixing a pair of disk-shaped flanges to both ends of the cylindrical body, or may be configured only by the cylindrical body.

[0065]

As described above, according to the first and seventh aspects of the present invention, since the cylindrical body is integrally formed of a thermosetting synthetic resin, it is not necessary to provide a rib inside the cylindrical body. , Can reduce the weight of the impression cylinder and improve rigidity, compared with the case of using a conventional aluminum extruded material.
Thermal deformation can also be reduced. Also, since the rubber layer is integrally formed on the outer peripheral surface of the cylindrical body, the adhesion of the rubber layer to the cylindrical body is strong, and the surface of the rubber layer is finished by grinding. Outer diameter accuracy can be improved.

According to the second aspect of the present invention, since the cylindrical body has a cup shape having a bottom plate at one end, and a disk-shaped flange is fixed to the other end of the cylindrical body, the strength of the impression cylinder is improved. be able to.

According to the third aspect of the present invention, since the sheet made of the synthetic resin film is wound around the outer peripheral surface of the rubber layer, the outer peripheral surface of the impression cylinder becomes low friction and non-adhesive, and The wiping property of the ink at the time of adhesion can be improved, and the adhesion of paper powder can be prevented.

According to the fourth aspect of the present invention, since the rubber layer is also provided in the concave portion for attaching the paper clamper, the rubber layer does not easily come off from the cylindrical body, and peels off due to insufficient adhesion between the cylindrical body and the rubber layer. Can be prevented.

According to the fifth aspect of the present invention, the outer diameter of each end of the cylindrical body gradually increases from the center to the end of the cylindrical body, and the thickness of the rubber layer corresponding to this gradually increases. However, since the thickness gradually decreases from the center to the end of the cylindrical body, the rigidity of both ends of the cylindrical body is improved. Therefore, the printing pressure is secured over the entire image area, and blurring or loss of the image can be prevented.

According to the sixth aspect of the present invention, when the impression cylinder is pressed against the plate cylinder, the thickness of the portion of the rubber layer that first comes into contact with the plate cylinder is thicker than the thickness of the other rubber layers. Therefore, the impact when the impression cylinder presses the plate cylinder is absorbed, and the amount of impact absorption can be increased. Therefore, bouncing between the impression cylinder and the plate cylinder is prevented, and the occurrence of white spots at the leading end of the image can be prevented. In addition, the printing pressure noise can be reduced.

According to the eighth aspect of the present invention, since the outer peripheral surface of the rubber layer is subjected to a surface treatment for lowering the friction coefficient and improving the non-adhesiveness, the outer peripheral surface of the rubber layer has low friction and low friction. It becomes non-adhesive, so that it is possible to improve the wiping property of the ink when the ink is applied, and it is possible to prevent the adhesion of paper powder.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a stencil printing apparatus.

FIG. 2 is a longitudinal sectional view of the impression cylinder in a generatrix direction.

FIG. 3 is a longitudinal sectional view of the impression cylinder in a circumferential direction.

FIG. 4 is an enlarged sectional view of a mounting portion of a clamper base.

FIG. 5 is an enlarged sectional view of an end portion of the impression cylinder.

FIG. 6 is a view for explaining a white spot phenomenon at the leading edge of an image on a sheet.

FIG. 7 is a view showing a second embodiment of the present invention, and is an enlarged sectional view of a mounting portion of a clamper base.

FIG. 8 is a view showing a third embodiment of the present invention, and is a longitudinal sectional view in the circumferential direction of the impression cylinder.

FIG. 9 is a view showing a fourth embodiment of the present invention, and is an enlarged sectional view of a wall portion of an impression cylinder.

FIG. 10 is a perspective view of an impression cylinder showing a configuration of a conventional impression cylinder.

[Explanation of symbols]

 Reference Signs List 1 plate cylinder 10 impression cylinder 11 shaft 17 recess 17b flat part 40 body part 40a bottom plate 40b open end 40c taper part 41 flange 50 rubber layer 50b thick part 51 nitrile rubber layer 52 silicon rubber layer 55 polyester sheet (synthetic resin film) 56 Hardened layer P paper

Claims (8)

[Claims] A thermosetting synthetic resin is used in an impression cylinder of a stencil printing machine that rotates while pressing a sheet fed by a sheet feeding means onto a rotating plate cylinder with a prepressed master mounted on the outer peripheral surface. And a rubber layer formed integrally with the outer peripheral surface of the cylindrical body, the surface of which is finished by grinding. 2. A stencil printing apparatus according to claim 1, wherein said cylindrical body has a cup shape having a bottom plate at one end, and a disc-shaped flange is fixed to the other end of said cylindrical body. Torso. 3. The impression cylinder of a stencil printing machine according to claim 1, wherein a sheet made of a synthetic resin film is wound around the outer peripheral surface of the rubber layer. 4. A concave portion for attaching a paper clamper extending in the generatrix direction is provided in a part of the outer peripheral surface of the cylindrical body, and the rubber layer is also provided in the concave portion. 4. An impression cylinder for a stencil printing apparatus according to claim 1, 2, or 3. 5. The outer diameter of each of predetermined areas at both ends of the cylindrical body gradually increases from the center to the end of the cylindrical body. 5. The impression cylinder of a stencil printing apparatus according to claim 1, wherein a thickness of the cylindrical body is gradually reduced from a center portion to an end portion. 6. When the impression cylinder is pressed against the plate cylinder,
The thickness of the portion of the rubber layer that first contacts the plate cylinder,
6. The impression cylinder for a stencil printing apparatus according to claim 1, wherein the thickness of the other portion of the rubber layer is larger than that of the other portion. 7. A method of manufacturing an impression cylinder of a stencil printing machine, which rotates while rotating a sheet fed by a sheet feeding means while pressing a pre-made master on an outer peripheral surface and rotating the plate cylinder. A cup-shaped cylindrical body having a bottom plate is integrally molded with a thermosetting synthetic resin, and a disc-shaped flange made of synthetic resin is fixed to the other end of the cylindrical body by bonding, and each center of the bottom plate and the flange is A method for manufacturing an impression cylinder, characterized in that a support shaft is inserted into the cylindrical body, a rubber layer is provided on the outer peripheral surface of the cylindrical body by integral molding, and the outer peripheral surface of the rubber layer is finished by grinding. 8. The method according to claim 7, wherein the outer peripheral surface of the rubber layer is subjected to a surface treatment for reducing the coefficient of friction and improving the non-adhesiveness.