JP2001246826A - Screen printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen printing apparatus reduced in cost by minimizing the arranging number of paper separation members and capable of well peeling paper corresponding to various images. SOLUTION: In the screen printing apparatus having a plate cylinder 29 having a master 22 wound around the outer peripheral surface thereof and a plurality of paper separation members 46 for peeling printing paper P from the outer peripheral surface of the plate cylinder 29, at least one of the paper separation members 46 is made movable in the axial direction of the plate cylinder 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing apparatus, and more particularly to a sheet separating mechanism for separating a printing sheet from an outer peripheral surface of a plate cylinder.

[0002]

2. Description of the Related Art A rotatable plate cylinder, which is a porous support cylinder, and a master having a laminate structure are used. The master is heated and perforated by a thermal head, then wound around the plate cylinder, and provided inside the plate cylinder. While the ink is supplied from the ink supply means, the printing paper is continuously pressed by the pressing means such as a press roller against the plate-making master on the outer peripheral surface of the plate cylinder, and the ink is exuded from the plate cylinder opening and the master perforated portion. 2. Related Art A thermal digital stencil printing apparatus that obtains a desired printed matter by transferring printing paper to the printing paper, peeling the printing paper from the outer peripheral surface of the plate cylinder, and discharging the printing paper to the outside of the machine is generally known.

In the above-described stencil printing apparatus, a sheet separating member is used to peel off printing paper stuck to a master on the outer peripheral surface of the plate cylinder by the adhesive force of ink supplied from the inside of the plate cylinder. The sheet separating member is generally made of resin, has a width of about 20 mm, and generally has a sharply pointed tip. In a normal stencil printing machine, the sheet separating member is located at the center of the plate cylinder in the axial direction. One is disposed at the position, and the leading end is inserted between the master and the printing paper to separate the printing paper. This sheet separating member is provided swingably so as to be able to approach and separate from the plate cylinder outer peripheral surface in order to prevent interference between a clamper provided on the plate cylinder outer peripheral surface and the leading end portion, In order to prevent the master on the plate cylinder from being damaged by the leading end, it is arranged near the outer peripheral portion of the plate cylinder so that there is a slight gap between the leading end and the master when approaching. In addition, the above-mentioned sheet separating member has a jet port for jetting gas at the leading end portion, and jets gas from the jet port between the master on the outer peripheral surface of the plate cylinder and the printing paper to form a gas on the outer peripheral surface of the plate cylinder. What has improved the performance of peeling printing paper from
For example, Japanese Unexamined Patent Publication No. 3-32878, Japanese Utility Model Publication No. 4-155
No. 09 discloses this.

[0004]

In the conventional stencil printing apparatus, since only one sheet separating member is provided as described above, printing paper having a solid image up to the vicinity of the sheet width at the leading end or the trailing end is used. At the time of peeling, there is a problem that a dragging image is generated at both ends of the solid image, resulting in poor printing. The sheet separating member has an effective separation area per sheet. If the end of the solid image portion exists outside this area, the printing paper is drawn toward the sheet separating member by the thickness of the sheet separating member, thereby forming a solid image. The part is shifted and a drag image is generated. Further, when the printing paper having the solid image at the rear end is peeled off, when the above-described paper separating member having the ejection port at the front end portion is used, when the paper separating member peels off the solid image, the ejection from the ejection port is performed. Since the ejection of the gas has ended, there is a problem that the leading end is stuck in the solid image portion.

Therefore, it is conceivable to provide a plurality of sheet separating members in the axial direction of the plate cylinder. Thereby, the above-mentioned problem is solved to some extent by the plurality of paper separating members coming into contact with the printing paper.However, to arrange the paper separating members corresponding to all the paper sizes used in the stencil printing apparatus, There is a problem that the number of paper separating members increases and the cost increases. Further, there are various types of original images to be printed, and since the sheet separating member has an effective separation area as described above, in order to satisfactorily separate various original images, a large number of images are formed in the plate cylinder axial direction. It is necessary to provide a paper separating member. When a large number of paper separating members are arranged, the gap adjustment between the leading end of each paper separating member and the outer peripheral surface of the plate cylinder is troublesome,
If the gap adjustment is incomplete, there is a problem that a paper separating member that enters between the outer peripheral surface of the plate cylinder and the printing paper and a paper separating member that cannot enter are mixed and a paper jam occurs during separation. There is.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, suppresses cost increase by minimizing the number of paper separating members provided, and enables stencil printing capable of performing excellent paper peeling corresponding to various images. The purpose is to provide the device.

[0007]

According to the first aspect of the present invention,
In a stencil printing machine having a plate cylinder around which a master is wound on an outer peripheral surface, and a plurality of sheet separating members for separating printing paper from the outer peripheral surface of the plate cylinder, at least one of the sheet separating members includes: It is characterized by being provided so as to be movable in the axial direction of the plate cylinder.

According to a second aspect of the present invention, in the stencil printing apparatus according to the first aspect, the movement of the sheet separating member is performed according to a print image transferred to the printing sheet.

According to a third aspect of the present invention, in the stencil printing apparatus according to the first or second aspect, the movable sheet separating member further separates the printing sheet from the outer peripheral surface of the plate cylinder. And a base for supporting the distal end, wherein the base is slidably supported by a support shaft provided in the stencil printing apparatus main body.

According to a fourth aspect of the present invention, in the stencil printing apparatus according to the third aspect, the plurality of paper separating members are capable of moving the leading end portions close to and away from the outer peripheral surface of the plate cylinder. As described above, the present invention is characterized in that the support shaft is integrally swingably supported by the support shaft.

According to a fifth aspect of the present invention, in the stencil printing apparatus of the third or fourth aspect, the movable sheet separating member further includes a positioning member for positioning and fixing the base with respect to the support shaft. It is characterized by having.

According to a sixth aspect of the present invention, in the stencil printing machine according to the fifth aspect, the positioning member further fixes the base portion from a side facing the outer peripheral surface of the plate cylinder via the support shaft. It is characterized by.

According to a seventh aspect of the present invention, in the stencil printing apparatus according to any one of the first to sixth aspects, further, the plurality of sheet separating members may have a width of 0. The tip portions are arranged so as to be positioned within a range of 94 times.

According to an eighth aspect of the present invention, in the stencil printing apparatus according to any one of the first to seventh aspects, further, at least one of the plurality of sheet separating members includes It is characterized by having an ejection port for ejecting gas to the outer peripheral surface of the plate cylinder.

[0015]

FIG. 1 is a schematic front view of a stencil printing apparatus employing a first embodiment of the present invention. In FIG. 1, the stencil printing apparatus 1 includes an image reading unit 2, a stencil conveying unit 3, a paper feeding unit 4, a printing unit 5, a stencil discharging unit 6, and a paper discharging unit 7. Image reading unit 2 arranged on the upper part of housing 1a which is the main body of the stencil printing apparatus
Has an original conveying roller pair 8, 9, a reflection mirror 10, an image forming lens 11, an image sensor 12 such as a CCD, and the like.

Below the image reading section 2, a plate making and conveying section 3 is provided. The stencil conveying unit 3 includes a master holding member 13,
Platen roller 14, thermal head 15, cutting means 16, master transport roller pair 17, 18, guide plate 1
9, 20, 21 and the like. Master holding member 13
Supports a core 22b of a master roll 22a formed by winding a master 22 in which a thermoplastic resin film and a porous support are bonded together in a roll shape, in a rotatable and detachable manner. The platen roller 14 is driven to rotate clockwise in the figure by a stepping motor (not shown), and the thermal head 15 is pressed against the platen roller 14 by urging means (not shown). The cutting means 16 having an upper blade and a lower blade cuts the master 22 when the upper blade moves up and down with respect to the lower blade. Master transport roller pair 1 consisting of a drive roller and a driven roller pressed against it
Reference numerals 7 and 18 convey the master 22 between the rollers. Guide plates 19 and 20 are provided between the master transport roller pairs 17 and 18, and a guide plate 21 is provided downstream of the master transport roller pair 18 in the master transport direction and fixed to a plate making side plate (not shown).

A paper feed unit 4 is provided below the plate making and conveying unit 3. The paper supply unit 4 includes a paper supply table 23 and a paper supply roller 2.
4, a separation roller 25, a registration roller pair 26, guide plates 27 and 28, and the like. The paper feed table 23 on which the printing paper P is loaded on the upper surface is vertically movably supported by a drive mechanism (not shown). The paper feed roller 24 disposed above the paper feed table 23 is driven to rotate clockwise in the figure by drive means (not shown). The uppermost printing paper P stacked on the paper feeding table 23 is pressed against the paper feeding roller 24 by a predetermined pressure. A separation roller 25 is provided near the left side of the paper feed roller 24. The separation roller 25 has a circumferential surface thereof pressed against a separation pad (not shown) at a predetermined pressure, and the driving force of the sheet feeding roller 24 is transmitted by a driving force transmitting means (not shown), so that the separation roller 25 moves in the same direction as the sheet feeding roller 24. Rotationally driven synchronously. On the left side of the separation roller 25, a registration roller pair 26 composed of a driving roller and a driven roller pressed against the driving roller is disposed. The driving roller of the registration roller pair 26 is driven to rotate by driving means (not shown), and the registration roller pair 26 is fed by the separation roller 25.
After the printing paper P is temporarily stopped, it is fed to the printing unit 5 at a predetermined timing. Registration roller pair 26
Guide plates 27 and 28 fixed to a plate making side plate (not shown) are disposed on the left side of the plate. A paper feed passage is formed in each of the guide plates 27 and 28.

A printing section 5 is provided on the left side of the sheet feeding section 4. The printing unit 5 mainly includes a plate cylinder 29, a press roller 30, and the like. The plate cylinder 29 which is configured to be capable of vertically feeding A3 paper and is detachably provided on the housing 1a has a porous support plate formed by etching a stainless steel plate or a nickel electroformed thin plate. The porous support plate is provided with a large number of holes having a diameter of about 0.15 to 0.5 mm at intervals of about 0.25 to 1.0 mm. On the surface of the opening of the porous support plate, the number of meshes woven with polyester or stainless steel thin wire #
A mesh screen of about 100 to 400 is wound about 1 to 3 layers, and a non-illustrated stage extending in the axial direction of the plate cylinder 29 on the surface of the non-opening portion of the porous support plate. A clamper 31 for holding the leading end of the master 22 is provided together with the stage. The clamper 31 is provided with a magnet (not shown), and is provided so as to be magnetically attached to a stage (not shown). When the plate cylinder 29 reaches a predetermined position, the clamper 31 is opened and closed by opening and closing means (not shown). Flanges (not shown) are provided at both ends of the porous support plate. Each flange is rotatably mounted on a support shaft 32 fixed to the housing 1a and also serving as an ink supply pipe via a bearing (not shown). Supported.

Inside the plate cylinder 29, an ink supply means 33 is provided. The ink supply unit 33 mainly includes a support shaft 32, an ink roller 34, and a doctor roller 35. A large number of holes for supplying ink to the inside of the plate cylinder 29 are formed in the surface of the support shaft 32. Support shaft 32
Below the ink roller 34 and the doctor roller 35
And are arranged. The ink roller 34 and the doctor roller 35 are rotatably supported between side plates (not shown) provided in the plate cylinder 29, and are rotationally driven in opposite directions by driving means (not shown). Ink roller 3
The doctor roller 4 and the doctor roller 35 are arranged close to each other such that a slight gap is formed between them, and a wedge-shaped ink reservoir 36 is formed in the vicinity of each outer peripheral surface. The ink supplied from the support shaft 32 to the ink reservoir 36 is supplied to the ink roller 34 and the doctor roller 3.
5 and is supplied to the inner peripheral surface of the plate cylinder 29 via the outer peripheral surface of the ink roller 34. Below the plate cylinder 29, a rotatable press roller 30 which is supported by a swinging means (not shown) and whose outer peripheral surface is freely pressed and separated from the outer peripheral surface of the plate cylinder 29 with a predetermined pressing force is arranged. Has been established. The press roller 30 presses the printing paper P fed from the paper feeding unit 4 against the plate cylinder 29,
A print image is formed on print paper P.

On the left side of the printing unit 5, a plate discharging unit 6 is provided. The plate discharging section 6 includes an upper plate discharging member 37, a lower plate discharging member 38,
It mainly comprises a plate discharging box 39 and the like. The upper plate discharging member 37 is mainly composed of a driving roller 40 and a driven roller 41 that are rotationally driven by a driving unit (not shown), and an endless belt 42 stretched between the rollers. The lower plate discharging member 38 mainly includes a driving roller 43, a driven roller 44, which is connected and driven by a driving roller 40 and a gear (not shown), and an endless belt 45 stretched between the rollers. The lower plate discharging member 38
The driving roller 43 is provided so as to be movable in the left-right direction about a support shaft of the driving roller 40 by a moving unit (not shown). . A plate discharging box 39 for storing used masters therein is provided detachably with respect to the housing 1a, and a compression plate (not shown) for compressing the stored used masters is provided inside the box.

Below the plate discharging section 6, a sheet discharging section 7 is provided. The paper discharge unit 7 includes a peeling claw 46 as a paper separating member,
It has a guide plate 47, a paper discharge transport member 48, a paper discharge tray 49, and the like. In this embodiment, three peeling claws 46 for peeling the printing paper P from the outer peripheral surface of the plate cylinder 29 are arranged in the axial direction of the plate cylinder 29 as shown in FIG. It has a portion 46a. Each peeling claw 46 has its base 46b attached to a support shaft 50 supported by a not-shown claw swinging means provided on the housing 1a. Each tip 46a is integrally swingably provided so as to be able to approach and separate from the outer peripheral surface of the plate cylinder 29. As shown in FIG. 3, a V-shaped groove 50a is formed on the support shaft 50, and a protrusion 46d fitted into the groove 50a is formed on a base 46b having a hole 46c into which the support shaft 50 can be fitted.
Are integrally formed. As a result, each peeling claw 46 is slidably supported in the axial direction of the plate cylinder 29 with its base 46b on the support shaft 50, and is fixed from above the protrusion 46b by a set screw 51 as a positioning member. . When the tip 46a approaches the outer peripheral surface of the plate cylinder 29, the gap between the distal end 46a and the outer peripheral surface of the plate cylinder 29 becomes an appropriate gap G (see FIG. 3). In addition, the formation position of each protrusion 46d is determined.

A guide plate 47 is provided on the left side of the press roller 30 and below the peeling claw 46. The guide plate 47 is fixed to a side plate (not shown) of the housing 1a.
The printing paper P peeled from the outer peripheral surface of the plate cylinder 29 by each of the peeling claws 46 is guided to the paper discharge transport member 48. Guide plate 4
On the left side of 7, a paper discharge transport member 48 is disposed. The paper discharge conveying member 48 includes a driving roller 53, a driven roller 54, a plurality of endless belts 55 stretched between the rollers, a suction fan 56, and the like, which are driven to rotate counterclockwise in FIG. And the printing paper P on the endless belt 55 by the suction force of the suction fan 56.
, And transported to the left in the figure. A discharge tray 49 is disposed on the left side of the discharge conveyance member 48. A discharge tray 4 on which printed printing paper P is stacked
9 is a pair of side fences 5 for aligning the printing paper P
7 and an end fence 58.

The operation of the stencil printing apparatus 1 based on the above configuration will be described below. First, the operator sets a document to be printed on the image reading unit 2. Then, the plate cylinder 29 is removed from the housing 1a, the set screw 51 is loosened, and each peeling claw 46 is positioned at a position corresponding to the solid image in the document image.
After the set screws 51 are tightened to position and fix the peeling claws 46, the plate cylinder 29 is mounted on the housing 1a. At this time, each peeling claw 46 is positioned such that its tip end 46a is located near the solid image. This is because, when the paper is placed at a position where it comes into direct contact with the solid image, the ink of the solid image portion adheres to the peeling nail 46 to cause nail mark stains on the image surface, or a large amount of ink is transferred, and the printing paper is reduced in strength. This is to prevent the peeling claw 46 from breaking through P.

When each of the peeling claws 46 is positioned and fixed at a predetermined position and an operator presses a plate making start key (not shown), the document conveying roller pairs 8 and 9 rotate to feed the document, and the reflecting mirror 10 moves the document image to the original image. Is scanned. The scanned document image is formed by the imaging lens 11 and then sent to the image sensor 12. After receiving the document image information, the image sensor 12 converts the information into an image data signal, and outputs the image data signal to control means (not shown) for controlling the thermal head 15.

In parallel with the image reading operation of the image reading unit 2, the plate discharging unit 6 performs a plate discharging operation of peeling the used master from the outer peripheral surface of the plate cylinder 29. The plate cylinder 29 on which the used master is wound on the outer peripheral surface is rotated in a counterclockwise direction in FIG. 1 by a plate cylinder driving unit (not shown). When the plate cylinder 29 reaches a predetermined plate discharging position where the rear end of the used master wound on the outer peripheral surface and the drive roller 43 correspond to each other, the respective drive rollers 40 and 43 are driven to rotate and move downward. The plate discharging member 38 is moved to the plate cylinder 29 side. When the outer peripheral surface of the drive roller 43 came into contact with the used master on the outer peripheral surface of the plate cylinder 29, the plate cylinder 29 continued to rotate in the counterclockwise direction, and was brought into contact with the drive roller 43 and picked up. The used master is sandwiched between the lower plate discharging member 38 and the upper plate discharging member 37 and is peeled from the outer peripheral surface of the plate cylinder 29. The peeled used master is the lower plate discharging member 3
After being conveyed by the plate discharge member 8 and the upper plate discharge member 37 and discarded in the plate discharge box 39, it is compressed by a compression plate (not shown). After all the used masters have been peeled off from the outer peripheral surface of the plate cylinder 29, the plate cylinder 29 further continues to rotate, and when the plate cylinder 29 reaches a predetermined plate feeding position shown in FIG. The operation of the driving means is stopped, and the opening / closing means (not shown) is operated, so that the clamper 31 is opened as shown in FIG. 1 and the plate cylinder 29 is in a plate feeding standby state.

When the plate cylinder 29 is in the plate feeding standby state and the plate discharging operation is completed, the plate making operation is performed subsequently. When the clamper 31 is opened, the platen roller 14 and the master transport roller pairs 17 and 18 are driven to rotate, and the master 22 is pulled out from the master roll 22a. In the drawn-out master 22, the heating element of the thermal head 15 selectively generates heat based on the image data signal, so that the thermoplastic resin film surface is hot-melt-perforated, and a plate-making image is formed. The master 22 having the plate making image formed thereon is guided by the guide plates 19, 20, and 21 while being clamped by the clamper 31.
Transported to When the control unit (not shown) recognizes that the leading end of the master 22 has been transported to the predetermined position between the clamper 31 and the stage unit (not shown) based on the number of steps of the stepping motor (not shown) that rotationally drives the platen roller 14, The opening / closing means (not shown) is operated to close the clamper 31, and the leading end of the master 22 is locked on the outer peripheral surface of the plate cylinder 29.

When the leading end of the master 22 is locked on the outer peripheral surface, the plate cylinder 29 starts to rotate again at the same peripheral speed as the master transport speed. When a control unit (not shown) recognizes that plate making for one plate has been completed based on the number of steps of a stepping motor (not shown) that rotationally drives the platen roller 15, the rotation of the platen roller 15 and the master transport roller pairs 17 and 18 is performed. Is stopped and the cutting means 6 is operated, and the master 22 is cut off. The cut master 22 is pulled out by the rotation of the plate cylinder 29,
Reaches a predetermined home position, the operation of the plate cylinder driving means (not shown) is stopped, and the winding operation is completed.

Subsequent to the winding operation, a printing operation is performed. After the winding operation is completed, a plate cylinder driving unit (not shown) is operated, and the plate cylinder 29 is driven to rotate at a low speed in the clockwise direction in FIG. 1, and the sheet feeding roller 24, the separation roller 25, the driving roller 53, and the suction fan 56 are respectively driven. Due to the rotation of the paper feed roller 24 and the separation roller 25, only the uppermost one of the print papers P stacked on the paper feed table 23 is drawn out, and the drawn out print paper P has its leading end paired with the registration roller. In addition to 26.
The registration roller pair 26 rotates at a predetermined timing,
The printing paper P is fed between the plate cylinder 29 and the press roller 30. The fed printing paper P is pressed by a press roller 30 which is oscillated by oscillating means (not shown).
9 is pressed with a predetermined pressing force. Due to this pressing operation, the press roller 30 and the outer peripheral surface of the plate cylinder 29 are pressed against each other via the printing paper P and the master 22 that has been made, and the ink supplied to the inner surface of the plate cylinder 29 by the ink roller 34 is used for opening the plate cylinder. The printing paper P is transferred to the printing paper P through the opening, the mesh screen opening, and the master perforation, and a print image is formed on the printing paper P. The printing paper P to which the ink has been transferred is peeled off from the outer peripheral surface of the plate cylinder 29 at the tip end portion 46a of each peeling claw 46, guided by the guide plate 47, and guided by the paper discharge transport member 4.
Sent to 8. The printing paper P held on the endless belt 55 by the suction force of the suction fan 56 is conveyed to the left and discharged onto the discharge tray 49, and the printing operation is completed. After the printing operation is completed, the printing drum 29 is rotated to the home position and stopped, and the stencil printing machine 1 is in a printing standby state. When the operator presses a printing start key (not shown) after the stencil printing apparatus 1 is in the printing standby state, the printing drum 29 is rotated at a higher speed than at the time of printing, and the paper feed roller 24 and the separation roller 25 are rotated. Is driven to rotate, and the printing paper P is continuously fed from the paper feeding unit 4 to perform a printing operation.

At the time of the above-mentioned printing and printing, the positioning and fixing of each peeling claw 46 is performed so that each tip 46a is located near the solid image of the master 22 wound on the outer peripheral surface of the printing drum 29. The minimum number of peeling nails 46
As a result, the printing paper P can be reliably separated from the outer peripheral surface of the plate cylinder 29, and the occurrence of a trailing image can be prevented to obtain a good printed matter. In addition, since each of the peeling claws 46 is disposed at a position where it does not directly contact the solid image, it is possible to prevent the generation of nail mark stains caused by the adhesion of ink to each of the peeling claws 46 and to make the printing paper by the peeling claws 46. P
Can be prevented, and a good printed matter can be obtained. In the above embodiment, the original image was confirmed and the positioning and fixing of each of the peeling claws 46 were performed before the plate making operation. However, after the winding operation, the plate cylinder 29 was pulled out of the housing 1a and wound on the plate cylinder 29. After confirming the master 22 that has been made, the positioning and fixing of each of the peeling claws 46 may be performed, and the printing paper P discharged by the printing after the printing operation may be checked and the positioning and fixing of each of the peeling claws 46 may be performed. You may.

FIG. 4 shows a peeling claw 52 as a sheet separating member used in the second embodiment of the present invention. The peeling claw 52 has an acute-angled tip 52a for peeling the printing paper P from the outer peripheral surface of the plate cylinder 29, and a base 5 supporting the tip 52a.
2b, and the sheet separating member 46 is provided on the base 52b.
A hole 52c and a protruding portion 52d similar to those described above are formed. The peeling claw 52 is configured such that the base portion 52 b is
And is fixed by a set screw 59 as a positioning member at a position facing the outer peripheral surface of the plate cylinder 29 via the support shaft 50. With the configuration described above, the set screw 59 is connected to the plate cylinder 2 via the support shaft 50.
Since the base 52d is fixed at a position opposed to the outer peripheral surface of the plate 9, the plate cylinder 29 does not need to be pulled out of the housing 1a when positioning and fixing the peeling claw 52, and the operability is improved.

FIG. 5 shows a peeling claw 60 and a support shaft 61 as a sheet separating member used in the third embodiment of the present invention. The peeling claw 60 has an acute-angled tip portion 60a for peeling the printing paper P from the outer peripheral surface of the plate cylinder 29, and a base portion 60b that supports the tip portion 60a. In base 60b,
A semicircular sliding portion 60c is formed so that the outer peripheral surface of the support shaft 61 can abut exactly. A semispherical sliding portion 60c is provided at a position facing the slide portion 60c via the support shaft 61 of the base portion 60b. A leaf spring 60e integrally having a positioning member 60d is provided. The leaf spring 60e urges the positioning member 60d against the support shaft 61 with a predetermined pressing force. As shown in FIG. 6, the support shaft 61 is formed with a positioning groove 61a having a shape of a series of circles into which the top of a positioning member 60d biased by a leaf spring 60e can be fitted. With the above-described configuration, the positioning and fixing can be performed without using a fastening member such as a set screw by sliding each peeling claw, so that the positioning of each peeling claw 60 can be easily performed.

In the above embodiment, the leaf spring 60e is used as a member for urging the positioning member 60d, but a compression spring or the like may be used instead of the leaf spring. Further, in the above embodiment, the positioning groove 61a having a shape in which a circle is connected to the support shaft 61 is formed. However, instead of the positioning groove, as shown in FIG. A configuration may be employed in which a plurality of positioning recesses 61b having a formed shape are formed. Further, as another modified example of the above embodiment, as shown in FIG. 8, a V-shaped groove 61c similar to the support shaft 50 is formed on the support shaft 61, and a protrusion that can be fitted into the groove 61c is formed on the base 60b. A configuration in which the portion 60f is formed may be adopted. This makes it possible to secure linearity when each of the peeling claws 60 slides, and it is possible to keep the gap G between each tip portion 60a and the outer peripheral surface of the plate cylinder 29 at a constant value.

In each of the above embodiments, a document image, a plate making image,
Alternatively, each peeling claw is positioned and fixed in accordance with the position of the solid image portion formed on the printing image. However, some images have a solid image portion formed over the entire width direction of the sheet. . Therefore, when obtaining printed matter,
The amount of trailing image generated according to the position of each peeling nail was investigated for each paper size. In the experiment, the number of peeling nails was three, the center peeling nail was positioned at the center of the paper, and the positions of the peeling nails on both sides were changed. Table 1 shows the results.

[0034]

[Table 1]

As is clear from the results shown in Table 1, when the positions of the peeling claws located on both sides are set to 0.94 times the sheet width, the generation amount of the trailing image is minimized in all the sheet sizes. It has been found. From this, when positioning and fixing the peeling claws, by setting the adjustment position of each peeling nail within the range of 0.94 times the sheet width, it is possible to effectively suppress the occurrence of the drag image and obtain a good image. Obtainable.

In each of the above embodiments and modifications, the peeling claw 4 having an acute-angled tip as the paper separating member is used.
6, 52 and 60 are shown, but as a paper separating member, for example, Japanese Utility Model Publication No. 4-15509, Japanese Patent Laid-Open No. 3-32878.
Or a device having an ejection port for ejecting gas to the outer peripheral surface of a plate cylinder or an impression cylinder at its tip end, such as that disclosed in Japanese Patent Application Laid-Open No. 11-334191 and Japanese Patent Application Laid-Open No. 11-334191. . As a result, the sheet separating performance can be greatly improved as compared with the sheet separating member described in each embodiment.

In each of the above embodiments and modified examples, the expression "positioning and fixing each peeling claw" is used, but the term "positioning and fixing" means that each peeling claw is integrally fixed to the support shaft. This does not mean that each peeling claw does not move with respect to the support shaft during the printing operation and the printing operation. Further, in each of the above embodiments and modifications, the number of peeling nails is three, but the number of peeling nails is two.
The number may be 4, 5, or more. However, considering the cost and the peeling performance of the printing paper, it is desirable to use five or less. In each of the above embodiments and modifications, all the peeling claws are configured to be slidable. However, when the number of the arranged peeling claws is three or more, the peeling nail located at the center (in the case of four, the center of the peeling nail is 2).
) May be fixed.

[0038]

According to the first, second, third, fourth and fifth aspects of the present invention, the separation of the printing paper from the outer peripheral surface of the plate cylinder is ensured by the minimum number of paper separating members. And a good printed matter can be obtained by preventing the occurrence of a drag image. In addition, since each sheet separating member is disposed at a position where the sheet separating member does not directly contact the solid image, it is possible to prevent clogging stains caused by ink adhering to each sheet separating member, and to prevent printing paper by each sheet separating member. Can be prevented, and a good printed matter can be obtained.

According to the sixth aspect of the present invention, it is not necessary to pull out the plate cylinder from the housing when positioning and fixing the sheet separating member, and the operability is improved.

According to the seventh aspect of the present invention, a good image can be obtained by effectively suppressing the occurrence of a drag image.

According to the eighth aspect of the present invention, by ejecting the gas, the sheet separating performance can be greatly improved.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a sheet separating member used in the first embodiment of the present invention.

FIG. 3 is a front view of a spindle and a sheet separating member used in the first embodiment of the present invention.

FIG. 4 is a front view of a support shaft and a sheet separating member used in a second embodiment of the present invention.

FIG. 5 is a front view of a spindle and a sheet separating member used in a third embodiment of the present invention.

FIG. 6 is a diagram illustrating a support shaft used in a third embodiment of the present invention.

FIG. 7 is a diagram illustrating a support shaft used in a modification of the third embodiment of the present invention.

FIG. 8 is a front view of a support shaft and a sheet separating member used in another modification of the third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 stencil printing machine 1a stencil printing machine main body (housing) 22 master 29 plate cylinder 46, 52, 60 paper separating member (peeling claw) 46a, 52a, 60a tip 46b, 52b, 60b base 50, 61 support shaft 51 positioning Member (Set screw) 60d Positioning member P Printing paper

Claims (8)

[Claims] 1. A stencil printing machine comprising: a plate cylinder on which a master is wound around an outer peripheral surface; and a plurality of sheet separating members for separating printing paper from the outer peripheral surface of the plate cylinder. At least one of the stencil printing machines is provided so as to be movable in an axial direction of the plate cylinder. 2. The stencil printing apparatus according to claim 1, wherein the movement of the paper separating member is performed in accordance with a print image transferred to the printing paper. 3. The stencil printing apparatus main body, wherein the movable paper separating member has a leading end for separating the printing paper from an outer peripheral surface of the plate cylinder and a base for supporting the leading end. 3. A stencil printing apparatus according to claim 1, wherein the stencil printing apparatus is slidably supported by a supporting shaft. 4. The plurality of paper separating members are supported by the support shaft so as to be swingable integrally so that the leading end portions can be freely moved toward and away from the outer peripheral surface of the plate cylinder. The stencil printing apparatus according to claim 3, wherein: 5. The stencil printing apparatus according to claim 3, wherein said movable sheet separating member has a positioning member for positioning and fixing said base with respect to said support shaft. 6. The stencil printing apparatus according to claim 5, wherein the positioning member fixes the base from a side facing the outer peripheral surface of the plate cylinder via the support shaft. 7. The printing apparatus according to claim 1, wherein the plurality of sheet separating members are arranged so that the leading ends thereof are positioned within a range of 0.94 times the width of the printing sheet. 7. The stencil printing apparatus according to any one of 6. 8. The printing apparatus according to claim 1, wherein at least one of said plurality of sheet separating members has an ejection port for ejecting gas to an outer peripheral surface of said plate cylinder.
The stencil printing apparatus according to any one of the above.