JP3254346B2 - Stencil printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing machine for printing by winding a perforated master.

[0002]

2. Description of the Related Art Digital thermosensitive stencil printing is known as a simpler printing method. This is achieved by bringing a thermal head, in which fine heating elements are arranged in a row, into contact with a heat-sensitive stencil master (hereinafter referred to as the “master”) and conveying the master while energizing the heating elements in a pulsed manner. The master is heated and melt-punched, and the master is wound on the outer peripheral surface of a porous cylindrical plate cylinder, and then the ink is transmitted through the perforated portion and transferred to printing paper to form a printed image. is there.

Generally, in a stencil printing machine of the type described above, the ink in the plate cylinder evaporates when the apparatus is left unused for a long time, and the ink runs short when printing is performed next time. Paper may be damaged. In order to minimize this problem, oily type that is difficult to evaporate and dry,
Alternatively, a water-in-oil (W / O type; water is dispersed in oil) type emulsion ink is generally used. However, since this ink is hard to dry, at the time of printing, the ink transferred to the printing paper penetrates into the printing paper and does not generate stains even when rubbed with a finger or the like, so-called,
It takes a certain amount of time to reach a state of being infiltrated and dried. If the next printing paper is loaded on the printed paper before the infiltration drying is completed, the ink is transferred to the back of the next printing paper on which the ink of the image portion of the printed paper is loaded, so-called so-called show-through. Failure occurs. This show-through is particularly likely to occur when printing a solid image with a large amount of ink transfer. Japanese Patent Application Laid-Open No. 4-361043 discloses a technique for covering the master opening with the outer peripheral surface of the ink roller and reducing the amount of ink transferred to the printing paper to prevent the occurrence of show-through. Japanese Patent Publication No. 63-593 discloses a technique in which an intermediate screen layer is provided between a support cylinder of a cylinder and a mesh screen layer to diffuse ink so that a large amount of ink is not locally transferred to printing paper.
No. 93, respectively.

[0004]

However, Japanese Patent Laid-Open Publication No.
According to the technology disclosed in Japanese Patent Application Laid-Open No. 61,043, since the thickness of the master is somewhat large, the flow of ink is not actually stopped when the printing paper is peeled from the plate-making master, and the amount of ink transferred to the printing paper is reduced. I haven't. Further, in the technique disclosed in Japanese Patent Publication No. 63-59393, although an intermediate screen layer is provided, the opening diameter of the outer screen layer is as large as about 45 μm, which is substantially the same as the opening diameter of the master. It is difficult to cut, and a large amount of ink is transferred to the printing paper, and the effect of reducing or preventing show-through has not been achieved.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stencil printing apparatus which can solve the above-mentioned problems and can prevent the occurrence of show-through to obtain a high quality printed image.

[0006]

According to the first aspect of the present invention,
A rotatable plate cylinder having a master made on its outer periphery wound thereon, ink supply means provided inside the plate cylinder, and pressing the printing paper against the master on the outer periphery of the plate cylinder A stencil printing apparatus including a pressing member that presses against the master by the pressing member .
The ink supplied from the supply means is transferred, and
For printing after being sent out from the contact portion with the pressing member
While pressing the paper against the outer peripheral surface of the pressing member by wind pressure,
Blow air to the printing paper to separate it from the master
The peeling claw to be performed and the peeling in the moving direction of the printing paper.
A suction fan that is disposed downstream of the release nail and suctions the printing paper;
And a separation radius of the printing paper when the printing paper is peeled off from the master, and
The sum with the winding radius of the master is 190 mm or less .

According to a second aspect of the present invention, a plate is formed on the outer peripheral surface.
A rotatable plate cylinder wound around the Mino master, and ink supply means provided in the interior of the plate cylinder, on the outer peripheral surface of the plate cylinder
A stencil printing apparatus, comprising: a press roller for pressing a printing sheet against the master, wherein the ink supply device is pressed by the master by the press roller.
The ink supplied from the step is transferred, and the plate cylinder and the press are transferred.
The printing after being sent out from the contact portion with the less roller
Pressing the paper against the outer peripheral surface of the press roller by wind pressure
While removing the printing paper from the master
A peeling claw that blows air, and
To remove the printing paper that is arranged downstream of the peeling claw.
That the suction fan and having a release means consisting, 190 m to the sum of the wrapped radius of said master of the press roller
m or less .

According to a third aspect of the present invention, a plate is formed on the outer peripheral surface.
A rotatable plate cylinder wound around the Mino master, said plate disposed inside the cylinder, a second spaced apart from the first position for pressing the outer peripheral surface to the inner circumferential surface of the plate cylinder An ink supply means having a rotatable ink roller capable of selectively taking a position and a moving means for moving the ink roller, and a pressing member for pressing printing paper against the master on the outer peripheral surface of the plate cylinder. Stencil printing machine with
The ink roller and the pusher occupying the first position.
The ink is supplied by being pressed against the master by a pressure member.
The ink supplied by the means is transferred, and the plate cylinder and the ink
The printing paper after being sent out from a contact portion with a pressing member
While pressing the outer peripheral surface of the pressing member by wind pressure.
Blow air to the printing paper to separate it from the
Peeling claw and the peeling in the moving direction of the printing paper.
A suction fan that is arranged downstream of the nail and sucks the printing paper.
Separating the printing paper from the mask.
Separation radius of the printing paper when peeled from the
The sum with the radius of the ink roller is set to 120 mm or less .

According to a fourth aspect of the present invention, plate making is performed on the outer peripheral surface.
A rotatable plate cylinder wound around the Mino master, said plate disposed inside the cylinder, a second spaced apart from the first position for pressing the outer peripheral surface to the inner circumferential surface of the plate cylinder An ink supply unit having a rotatable ink roller capable of selectively taking a position and a moving unit for moving the ink roller; and a press roller for pressing a printing sheet against the master on the outer peripheral surface of the plate cylinder. Stencil printing machine with
The ink roller occupying the first position and the front
Pressed by the press roller against the master,
The ink supplied from the ink supply means is transferred, and
Sent from the contact area between the plate cylinder and the press roller
After the printing paper is pressed against the outer peripheral surface of the press roller by wind pressure
The mark to separate from the master while pressing
A peeling claw that blows air to the printing paper, and a transfer of the printing paper.
The printing device is disposed on the downstream side of the peeling nail in the moving direction.
Having a peeling means consisting of a suction fan for sucking the paper,
Radius of the press roller and radius of the ink roller
Is 120 mm or less .

[0010]

FIG. 1 is a side view showing a main part of a stencil printing apparatus employing a first embodiment of the present invention. In the figure, the plate cylinder 1 has a large number of apertures 1a on its outer peripheral surface,
It is rotationally driven about a support shaft described later by a plate cylinder driving means (not shown). On the outer peripheral surface of the plate cylinder 1, about 1 to 3 layers of a mesh screen (not shown) having a mesh number of about # 100 to # 400 woven with a thin line of polyester or stainless steel are wound. Further, on the outer peripheral surface of the plate cylinder 1, a stage portion 2 extending in the same direction as the axis of the plate cylinder 1 and a clamper 3 for holding the leading end of the master together with the stage portion 2 are arranged. The clamper 3 is a spindle 3a
The stage 2 is rotatably supported, and is provided so as to be able to contact and separate from the stage 2. The clamper 3 is rotated by opening / closing means (not shown), and can selectively take a position where it comes into contact with the stage 2 and a position where it is separated from the stage 2.

Inside the plate cylinder 1, an ink supply means 4 is provided. The ink supply means 4 mainly includes an ink supply pipe 5, an ink roller 6, and a doctor roller 7.

An ink supply pipe 5 serving also as a support shaft of the plate cylinder 1 is fixed to a casing side plate (not shown), and has countless small holes on its surface for supplying ink to the inside of the plate cylinder 1. Has been drilled. Below the ink supply pipe 5, an ink roller 6 and a doctor roller 7 are provided. The ink roller 6 rotatably supported by a side plate (not shown) of the plate cylinder 1 is provided with a slight gap between its outer peripheral surface and the inner peripheral surface of the plate cylinder 1, and a pressing action of a press roller described later. As a result, the outer peripheral surface of the plate cylinder 1 is brought into contact with the inner peripheral surface of the plate cylinder 1, and the ink supplied from the ink supply pipe 5 is supplied to the plate cylinder 1. In the vicinity of the ink roller 6, a rotatable doctor roller 7 is provided. The doctor roller 7 is disposed so that a slight gap is formed between the outer peripheral surface of the doctor roller 7 and the outer peripheral surface of the ink roller 6. Has formed. The ink supplied from the ink supply pipe 5 to the ink reservoir 8 passes through the gap between the ink roller 6 and the doctor roller 7 and is supplied to the surface of the ink roller 6 while forming a uniform layer.

Below the plate cylinder 1, a rotatable press roller 9 which is supported by a swinging means (not shown) and whose outer peripheral surface is freely movable toward and away from the outer peripheral surface of the plate cylinder 1 is provided. ing. The press roller 9 as a pressing member presses the fed printing paper against the plate cylinder 1 to form a print image on the printing paper.

At the upper left of the plate cylinder 1, a plate making section 10 is provided. The plate making unit 10 mainly includes a master storage unit 11, a plate making unit 12, a conveying unit 13, a cutting unit 14, and the like.

The master storage means 11 rotatably supports a core 16a of a master roll 16 in which a master 15 is wound into a roll. On the right side of the master storage means 11, a plate making means 12 is provided. The plate making means 12 mainly includes a platen roller 17, a thermal head 18, and the like. The platen roller 17 is rotatably supported by a side plate of a casing (not shown) and is driven to rotate by a stepping motor (not shown). The thermal head 18 having a large number of heating elements therein is attached to a side plate of a housing (not shown), and is urged by an urging means (not shown) and pressed against the platen roller 17. On the downstream side of the master making means 12 in the master conveying direction, a conveying means 13 including a driving roller 13a rotated by a driving means (not shown) and a conveying roller pair composed of a driven roller 13b rotating with the driving roller 13a is provided. ,
Further downstream, there is a fixed blade 1 attached to the housing.
4a and a movable blade 14b moving with respect to the fixed blade 14a
And a guide plate 19 for guiding the transfer of the master.

A registration roller pair 2 is provided on the lower right side of the plate cylinder 1.
0 is provided. The registration roller pair 20 picks up the printing paper 21 fed from a paper feeding means (not shown), and synchronizes with the outer peripheral surface of the plate cylinder 1 and the press roller in synchronization with the rotation of the plate cylinder 1 and the swing of the press roller 9. 9, the printing paper 21 is fed.

A paper discharge section 22 is provided at the lower left of the plate cylinder 1. The paper discharge unit 22 includes a peeling claw 23 as a peeling unit,
Driven roller 24, drive roller 25, rubber belt 2
6. Suction fan 27 as peeling means, paper discharge tray 28
It is mainly composed of

A peeling claw 23 for peeling the printing paper 21 to which the ink has been transferred from the outer peripheral surface of the plate cylinder 1 is rotatably supported by a casing side plate (not shown).
Is disposed so as to be able to freely contact and separate from the outer peripheral surface of the. Peeling nail 2
The plate 3 is rocked by a rocking means (not shown). The rocking is synchronized with the rotation of the plate cylinder 1 so that an obstacle such as the clamper 3 existing on the outer peripheral surface of the plate cylinder 1 does not interfere with the tip. Has been taken. A blower (not shown) is connected to the peeling claw 23, and an opening (not shown) is formed at the tip thereof. The peeling claw 23 blows air from the leading end toward the outer peripheral surface of the plate cylinder 1.

The driven roller 24 and the driving roller 25 are rotatably supported by the casing side plate, and a rubber belt 26 having a plurality of openings on the surface is stretched between the rollers. The driving roller 25 is rotationally driven by a driving unit (not shown), and the rotational force is transmitted to the driven roller 24 via a rubber belt 26. The linear velocity of the rubber belt 26 is set to be slightly higher than the peripheral velocity of the plate cylinder 1. Below the driven roller 24 and the driving roller 25, a suction fan 27 as a peeling means for sucking the printing paper 21 on which the print image is formed on the surface of the rubber belt 26 is provided. On the downstream side of the drive roller 25 in the print paper transport direction, a paper discharge tray 28 for loading the print paper 21 on which the print image is formed is provided.
The paper discharge tray 28 is detachably attached to the housing.

The operation of the first embodiment based on the above configuration will be described below. When a document is set on a document reading unit (not shown) and a plate making start key (not shown) is pressed, the plate cylinder 1 is rotated, and the used master wound around the outer peripheral surface of the plate cylinder 1 by a plate discharging device (not shown) is peeled off. The plate cylinder 1 is discarded, and stops at the plate-supply standby position where the clamper 3 is located almost directly above. When the plate cylinder 1 stops, the opening / closing means (not shown) operates to open the clamper 3, and the plate cylinder 1 enters a plate feeding standby state shown in FIG.

When the plate discharging operation is completed, a plate making operation is performed subsequently. The read document image is converted into an electric signal by a CCD or the like of the document reading unit, and is sent as image data to a plate making control device via an A / D converter. The plate making control device energizes the heating elements of the thermal head 18 in a pulsed manner based on the sent image data, and the thermal head 18 performs perforating plate making on the master 15. Prior to the operation of the thermal head 18, the platen roller 17
Are rotated by a stepping motor (not shown), and the master 15 is pulled out from the master roll 16.

The master 15 on which the plate-making image is formed is conveyed to the clamper 3 by the conveying means 13 while being guided by the guide plate 19. From the number of steps of the stepping motor for driving the platen roller 17,
When the tip of the master reaches a predetermined position between the clamper 3 and the stage 2, an opening / closing means (not shown) operates to rotate the clamper 3 in a counterclockwise direction, and the stage 15 and the clamper 3 After holding the leading end, the plate cylinder 1 starts rotating at a peripheral speed substantially equal to the master transport speed, and winding of the master 15 around the plate cylinder 1 is started. Then, when it is determined from the number of steps of the stepping motor that drives the platen roller 17 that plate making for one plate has been completed, the rotation operations of the platen roller 17 and the transport unit 13 are stopped, and the cutting unit 14 causes the master 15 to rotate. Is disconnected. The cut master 15 is pulled out by the rotation of the plate cylinder 1, and the winding operation is completed.

Following the winding operation, a plate attaching operation is performed. The printing paper 21 fed from paper feeding means (not shown) is fed into the registration roller pair 20. The registration roller pair 20 moves the printing paper 21 between the plate cylinder 1 and the press roller 9 when the image area of the master 15 wound around the plate cylinder 1 rotating at a low speed reaches a position corresponding to the press roller 9. Feed between. Printed paper 2 fed
1 is pressed against a master 15 wound around the plate cylinder 1 by a press roller 9 oscillated by oscillating means (not shown). By this pressing operation, the press roller 9, the printing paper 21, the master 15, and the outer peripheral surface of the plate cylinder 1 are pressed against each other,
The ink supplied to the inner peripheral surface of the plate cylinder 1 by the ink roller 6 oozes out from the opening 1a of the plate cylinder 1 and the mesh screen, and is then filled in the gap between the outer peripheral surface of the plate cylinder 1 and the master 15. The image is transferred to the printing paper 21 via the perforated portion of the master 15.

In FIG. 2, the printing paper 21 to which the ink has been transferred is peeled off from the outer peripheral surface of the plate cylinder 1 at the tip of the peeling claw 23, and falls downward by blowing air from the peeling claw 23.
The air is conveyed to the left while being attracted to the upper surface of the rubber belt 26 located below by the air blowing from the air blowing means and the suction force of the suction fan 27. Since the linear velocity of the rubber belt 26 is set to be slightly higher than the peripheral velocity of the printing drum 1, the printing paper 21 presses the press roller 9 in a direction in which the printing paper 21 is peeled off from the master 15 wound on the outer peripheral surface of the printing drum 1. The sheet is conveyed while being peeled along the outer peripheral surface of the sheet, and is discharged onto the sheet discharge tray. The printing operation is completed by the above-described series of steps.

When the printing start key (not shown) is pressed by the operator after the printing operation is completed, the printing paper is continuously fed from the paper feeding means (not shown), and the printing drum 1 rotates at a high speed to perform the printing operation. Will be

In the above operation, when the printing paper 21 is peeled off from the surface of the plate cylinder 1, the ink drawn out from the perforated portion 15 a of the master 15 by the adhesive force between the ink on the surface of the master 15 and the printing paper 21. The amount of 29 is shown in FIG.
As schematically shown, there is a relationship with the separation radius R when the printing paper 21 is peeled off. The smaller the separation radius R, the more quickly the printing paper 21 is peeled away from the master 15, so that the viscosity is high and the flow is high. The ink 29 having poor properties is torn before being pulled out from the perforated portion 15a,
The amount of the ink 29 transferred to the surface of the printing paper 21 is reduced. FIG. 4 shows the transfer state of the ink 29 when the separation radius R is small, and FIG. 5 shows the transfer state of the ink 29 when the separation radius R is large.

In the actual stencil printing apparatus, the separation radius R is determined from the winding radius R1 of the master 15 and the separation radius rm when the printing paper 21 is peeled off (see FIG. 6). The smaller the sum with the separation radius rm, the smaller the amount of ink transferred to the printing paper 21 and the more the occurrence of show-through can be prevented.

In the present invention, since the printing paper 21 peels off along the outer peripheral surface of the press roller 9, the separation radius rm of the printing paper 21 = the radius r1 of the press roller 9. In addition, the total thickness of the master 15 and the mesh screen is generally about 80 μm, and becomes thinner when pressed by the press roller 9, so that the winding radius R 1 of the master 15 is equal to the radius Rm of the plate cylinder 1. be able to. Therefore, printing is performed while changing the radius Rm of the plate cylinder 1 and the radius r1 of the press roller 9 (printing conditions: ink viscosity 7 Pa ·
s, printing speed: 60 sheets / min, temperature: 20 ° C., humidity: 60
%), And show-through when the printing paper 21 was peeled along the outer peripheral surface of the press roller 9 was examined (see FIG. 7). The results are shown in Tables 1, 2 and 3, respectively.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

From the result of this investigation, the radius Rm of the plate cylinder 1
The sum Rm + r of (the winding radius R1 of the master 15) and the radius r1 of the press roller 9 (the separation radius rm of the printing paper 21).
When 1 (R1 + rm) was 190 mm or less, there was little show-through. In particular, when the thickness was 120 mm or less, show-through was fairly small and good.

FIG. 8 is a side view showing a main part of a stencil printing apparatus employing a second embodiment of the present invention. In the figure,
The same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The plate cylinder 30 includes a support cylinder 31 having a large number of apertures 31a, a front flange 32a for supporting both side ends of the support cylinder 31, a flange depth 32b, and flanges 32a and 32b in the axial direction. It is mainly composed of a stage section 33 to be connected, and is rotated around the ink supply pipe 5 by plate cylinder driving means (not shown). Further, on the outer peripheral surface of the support cylinder 31, the number of meshes # 100 to # 100 woven with polyester or stainless steel thin wire or the like is used.
About 400 mesh screens (not shown) are wound about 1 to 3 layers. One end of the support cylinder 31 is fixed to the stage 33, and the other end is attached to one end of a tension coil spring 34. Extension coil spring 34
Is attached to the stage 33.

Inside the plate cylinder 30, an ink supply means 35 is provided. The ink supply means 35 includes an ink supply pipe 5, an ink roller 36, a doctor roller 37,
It mainly comprises a solenoid 38 as a moving means.

Each flange 32a, 3 inside the plate cylinder 30 of the ink supply pipe 5 also serving as a support shaft of the plate cylinder 30.
A pair of fixing plates 39a and 39b are fixed to a portion closer to 2b. A support shaft 40 is provided between the fixed plates 39a and 39b.
Are rotatably supported, and a solenoid 38 is attached to one fixed plate 39b . The swinging plates 41a, 4b are provided at portions of the support shaft 40 near the fixed plates 39a, 39b.
1b is fixed, and an ink roller 36 and a doctor roller 37 are rotatably mounted between the swing plates 41a and 41b. The ink roller 36 and the doctor roller 37 are mounted so as to have the same positional relationship as the ink roller 6 and the doctor roller 7 in the first embodiment. 8 are formed.

A free end of the one swing plate 41b opposite to the base end fixed to the support shaft 40 is attached to a plunger 38a of the solenoid 38. The swing plate 41b
One end of a tension coil spring 42, the other end of which is fixed to a fixing plate 39b , is attached to a free end near the portion attached to the plunger 38a.

With the above configuration, the ink supply means 35
When the solenoid 38 is not operated, the tension coil spring 4
Each swing plate 41a by 2, 41b is placed in the position of a diagram pulled upward, at the time of actuation of the solenoid 38
The outer peripheral surface of the ink roller 36 is placed at a position where the inner peripheral surface of the plate cylinder 30 is pressed. In the figure, reference numeral 43 denotes the swing plate 4
This is a stopper for restricting the upward swing of 1a. What
Contact, solenoid 38, plunger 38a, and tension coil
The spring 42 has the other fixed plate 39a and the swing plate 41a.
It may be similarly provided on the side.

The operation of the second embodiment based on the above configuration will be described below. When a document is set on a document reading unit (not shown) and a plate-making start key (not shown) is pressed, the first
In the same manner as in the embodiment, the plate discharge is performed, and the plate cylinder 30 enters a plate supply standby state shown in FIG. When the plate discharging operation is completed, the plate making operation and the winding operation are performed in the same manner as in the first embodiment, and the plate attaching operation is performed following the winding operation.

The printing paper 21 fed from paper feeding means (not shown) is fed into the registration roller pair 20. The registration roller pair 20 moves the printing paper 21 between the plate cylinder 30 and the press roller 9 at the timing when the image area of the master 15 wound around the plate cylinder 30 rotating at a low speed reaches a position corresponding to the press roller 9. Feed between. When the printing paper 21 is fed by the registration roller pair 20, the press roller 9 is oscillated by oscillating means (not shown), and the solenoid 38 is operated based on a signal from control means (not shown). The outer peripheral surface is pressed against the inner peripheral surface of the plate cylinder 30. Ink roller 3
6, the support cylinder 31 is pushed radially outward by extension of the extension coil spring 34, and the shape of the support cylinder 31 pressed against the ink roller 36 is changed to the shape of the ink roller 36. follow. Printing paper 2
1 is an ink roller 36 by a press roller 9.
Is pressed by the master 15 wound around the plate cylinder 30 following the shape of. By this pressing operation, the press roller 9, the printing paper 21, the master 15, and the outer peripheral surface of the support cylinder 31 are pressed against each other, and the ink supplied to the inner peripheral surface of the plate cylinder 30 by the ink roller 36 is applied to the support cylinder 31. After being exuded from the opening 31a and the mesh screen, the gap between the outer peripheral surface of the plate cylinder 30 and the master 15 is filled and transferred to the printing paper 21 through the perforated portion of the master 15.

The printing paper 21 to which the ink has been transferred is the first
In the same manner as in the embodiment, the sheet is conveyed while being separated from the plate cylinder 30 along the outer peripheral surface of the press roller 9 (see FIG. 9), and is discharged onto the sheet discharge tray 28. Through the above series of steps,
The printing operation is completed.

When the printing start key (not shown) is pressed by the operator after the printing operation is completed, the printing paper is continuously fed from the paper feeding means (not shown), and the printing cylinder is rotated at a high speed to perform the printing operation. Will be

During the above operation, the amount of the ink 29 drawn out from the perforated portion 15a of the master 15 when the printing paper 21 is peeled off from the surface of the plate cylinder 30 is the same as in the first embodiment. This is related to the separation radius R when the sheet 21 is peeled off. The smaller the separation radius R is, the smaller the amount of the ink 29 transferred to the surface of the printing sheet 21 is.

In the second embodiment, the separation radius R is determined by the separation radius rm of the printing paper 21 = the radius r1 of the press roller 9 and the winding radius R1 of the master 15. Here, at the time of printing, the shape of the support cylinder 31 follows the shape of the ink roller 36, and
The thickness of the master 1 and the master 15 is generally 100 μm even when combined.
m, and becomes even thinner when pressed by the press roller 9, so that the winding radius R1 of the master 15 can be regarded as the radius R2 of the ink roller 36. Therefore,
Printing is performed by changing the radius R2 of the ink roller 36 and the radius r1 of the press roller 9 (printing conditions: ink viscosity ...
7 Pa · s, printing speed: 60 sheets / min, temperature: 20 ° C., humidity: 60%), and show-through when the printing paper 21 was peeled off along the outer peripheral surface of the press roller 9 was investigated (see FIG. 10). . The results are shown in Tables 4, 5, and 6, respectively.

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Table 6]

From the results of this investigation, it was found that the ink roller 36
When the sum R2 + r1 (R1 + rm) of the radius R2 (the winding radius R1 of the master 15) and the radius r1 of the press roller 9 (the separation radius rm of the printing paper 21) was 120 mm or less, show-through was small. In particular, when the thickness was 55 mm or less, show-through was fairly small and good.

In each of the above-described embodiments, the peeling claw 23 and the suction fan 27 connected to the blowing means are used as the peeling means, but another blowing means may be provided.

[0050]

According to the first aspect of the present invention, the separation radius of the printing paper when the printing paper is peeled from the pre-made master along the outer peripheral surface of the pressing member, and the winding of the pre-made master .
If the sum with the landing radius is 190 mm or less, the printing paper will be quickly peeled away from the plate-making master,
Ink having high viscosity and poor fluidity is torn before being pulled out from the perforated portion of the plate-making master, and the amount of ink transferred to the surface of the printing paper is reduced, so that show-through can be prevented. The printing paper separation radius and
When the sum with the winding radius of the printed master is 120 mm or less, show-through can be effectively prevented.

According to the second aspect of the present invention, the printing paper is
Peel the master from the plate-making master along the outer circumference of the press roller.
The radius of the press roller when it comes off and the
If the sum with the winding radius is 190 mm or less, since the printing paper is quickly peeled away from the pre-made master, the ink having high viscosity and poor fluidity is torn before being pulled out from the perforated portion of the pre-made master, Since the amount of ink transferred to the surface of the printing paper is reduced, show-through can be prevented. Also, press roller half
When the sum of the diameter and the winding radius of the plate-making master is 120 mm or less, show-through can be effectively prevented.

According to the third aspect of the present invention, the printing paper is
Along the outer circumferential surface of the pressing member of the printing paper when detached from stencil master separation radius of the ink roller radius and the
If the sum is 120 mm or less, the printing paper is quickly peeled away from the plate-making master following the shape of the ink roller, so that the ink having high viscosity and poor fluidity is torn before being pulled out from the perforated portion of the plate-making master. As a result, the amount of ink transferred to the surface of the printing paper is reduced, so that show-through can be prevented. Also printing
The sum of the separation radius of the paper and the radius of the ink roller is 55 m
When the value is m or less, show-through can be effectively prevented.

According to the fourth aspect of the present invention, the printing paper is
Peel the master from the plate-making master along the outer circumference of the press roller.
Of the press roller of the radius and the ink rollers of the time is
If the sum of the radius and the radius is 120 mm or less, the printing paper is quickly peeled away from the plate-making master following the shape of the ink roller, so that the ink having high viscosity and poor fluidity is drawn out from the perforated portion of the plate-making master. Since the amount of ink transferred to the surface of the printing paper is reduced, show-through can be prevented. Also, the radius of the press roller and the radius of the ink roller
When the sum is 55 mm or less, show-through can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a main part of a stencil printing apparatus employing a first embodiment of the present invention.

FIG. 2 is a partial side view illustrating the first embodiment of the present invention.

FIG. 3 is a diagram illustrating adhesion of ink to printing paper for explaining a first embodiment of the present invention.

FIG. 4 is a diagram illustrating the adhesion of ink to printing paper when the separation radius is small, explaining the first embodiment of the present invention.

FIG. 5 is a diagram illustrating the adhesion of ink to printing paper when the separation radius is large, explaining the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a first embodiment of the present invention.

FIG. 7 is a diagram illustrating a first embodiment of the present invention.

FIG. 8 is a schematic side view of a main part of a stencil printing apparatus employing a second embodiment of the present invention.

FIG. 9 is a partial side view illustrating a second embodiment of the present invention.

FIG. 10 is a diagram illustrating a second embodiment of the present invention.

[Explanation of symbols]

1, 30 plate cylinder 4, 35 ink supply means 9 pressing member (press roller) 21 printing paper 23 peeling means (peeling claw) 27 peeling means (suction fan) 36 ink roller 38 moving means (solenoid)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41L 13/04 B41L 13/18

Claims (4)

(57) [Claims] 1. A rotatable plate cylinder having a master formed thereon wound on its outer peripheral surface, ink supply means provided inside the plate cylinder, and a master on the outer peripheral surface of the plate cylinder. Stencil printing machine equipped with a pressing member for pressing the printing paper
The pressing member presses the master to
The ink supplied from the ink supply means is transferred to the plate cylinder;
The mark after being sent out from a contact portion between the mark and the pressing member
While pressing the printing paper against the outer peripheral surface of the pressing member by wind pressure
Feed the printing paper to separate it from the master
A peeling claw for blowing air, and a front in the moving direction of the printing paper
A suction device that is disposed downstream of the peeling nail and suctions the printing paper.
A separating means comprising a drawing fan, and a sum of a separation radius of the printing paper and a winding radius of the master when the printing paper is peeled from the master is 190.
mm or less . 2. A rotatable plate cylinder having a plate-making master wound on its outer peripheral surface, ink supply means provided inside the plate cylinder, and a master on the outer peripheral surface of the plate cylinder. stencil printing; and a press roller for pressing the printing paper Te
In the apparatus, before being pressed by the press roller by the master,
The ink supplied from the ink supply means is transferred and
Sent out from the contact part between the printing cylinder and the press roller
After the printing paper is blown on the outer circumferential surface of the press roller,
To separate from the master while pressing by pressure
A peeling claw that blows air to the printing paper; and
The mark is disposed on the downstream side of the peeling claw in the moving direction.
Has peeling means consisting of a suction fan that sucks the printing paper
Between the radius of the press roller and the winding radius of the master.
A stencil printing machine characterized in that the sum is 190 mm or less . 3. A rotatable plate cylinder having a master formed thereon wound on an outer peripheral surface thereof, and an outer peripheral surface thereof being pressed against an inner peripheral surface of the plate cylinder provided inside the plate cylinder. An ink supply means having a rotatable ink roller capable of selectively taking a first position and a second position apart from the first position, and a moving means for moving the ink roller; and an outer peripheral surface of the plate cylinder.
And a pressing member for pressing the printing paper against said master .
A stencil printing apparatus provided with the ink roller and the pressing portion occupying a first position.
The ink supply means being pressed against the master by a material
The ink supplied is transferred to the plate cylinder and the press
The printing paper after being sent out from the contact portion with the member is
The master is pressed against the outer peripheral surface of the pressing member by wind pressure.
Blow off the printing paper to separate it from
A release nail, and a release nail in the moving direction of the printing paper.
A suction fan arranged on the downstream side to suction the printing paper;
The printing when the printing paper is peeled from the master
The sum of the separation radius of the paper and the radius of the ink roller is 1
A stencil printing apparatus characterized in that the diameter is 20 mm or less . 4. A rotatable plate cylinder having a master formed thereon wound on an outer peripheral surface thereof, and an outer peripheral surface thereof being pressed against an inner peripheral surface of the plate cylinder provided inside the plate cylinder. An ink supply means having a rotatable ink roller capable of selectively taking a first position and a second position apart from the first position, and a moving means for moving the ink roller; and an outer peripheral surface of the plate cylinder.
A stencil printing apparatus comprising a press roller for pressing a printing sheet against the master , wherein the ink roller and the press occupying a first position.
The ink is pressed against the master by a roller.
The ink supplied from the supply means is transferred, and
The above after being sent out from the contact portion with the press roller
Pressing the printing paper against the outer peripheral surface of the press roller by wind pressure
Pressing on the printing paper to separate from the master while pressing
A peeling claw that blows air to the printing paper in the moving direction of the printing paper.
In the downstream side of the peeling claw to absorb the printing paper.
A suction fan for pulling, a radius of the press roller and a radius of the ink roller.
A stencil printing apparatus characterized in that the sum of the stencil printing and the stencil printing is 120 mm or less .