JP2000085233A - Stencil printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress a release miss with a simple and low-cost constitution by providing a friction reducing member at a contact dealing site of an outer periphery of a plate cylinder at a release roller, in a stencil printer having a master wound on the periphery of the cylinder and brought into contact with the roller to release the master and to deliver it. SOLUTION: A plate cylinder 14 of the stencil printer has a cylindrical porous support plate 40 and an engraved master 46 wound on one to three mesh screen layers 42 arranged on an outer periphery of the plate 40 and a clamper 18 for holding an end of the master 46. In order to release and deliver the master 46 on the cylinder 14, a plate delivering means 30 having a plate delivering roller mechanism 32 and a plate delivering box 34 is provided. In this case a friction reducing member 44 made of a plain weave sheet or the like of synthetic fibers is provided at a corresponding site brought into contact with a release roller 36 in the mechanism 32 of the layers 32. Thus, an end of the master 46 can be easily released by rotation of the roller 36.

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 stencil printing apparatus for releasing a master by releasing a master by contacting a peeling roller when printing is completed.

[0002]

2. Description of the Related Art In a stencil printing apparatus, generally, a master made by a thermal head or the like based on read information of an original image is wound around an outer peripheral surface of a plate cylinder, and printing paper sent at a predetermined timing is printed. 2. Description of the Related Art A system in which printing is performed by pressing a plate cylinder with a press roller or the like is known. As shown in FIG. 9, the plate cylinder 100 mainly includes a cylindrical porous support plate 102 formed of a stainless steel thin plate or the like.
On the outer peripheral surface of the porous support plate 102, about 1 to 3 mesh screen layers 104 woven with a thin line of polyester or stainless steel, etc., in order to improve the diffusion and containment of the ink supplied from the inside of the plate cylinder. Is formed. Plate cylinder 10
A clamper 106 is provided on a part of the outer peripheral surface of the master cylinder 0. In the plate feeding process, the leading end of the master 108, which has been made, is clamped by the clamper 106.
Is rotated, the master 108 is wound around the outer peripheral surface of the plate cylinder 100.

When printing of a predetermined number of sheets by one plate (master) is completed, the process proceeds to a plate discharging process, in which the used master 10 is used.
8 is removed from the outer peripheral surface of the plate cylinder 100. This master 1
08 is removed by removing the peeling roller 110 and the peeling roller 1.
This is performed by a plate discharge roller mechanism composed of a transport roller 112 pressed against the plate 10. The plate discharge roller mechanism is entirely swingable about the axis of the transport roller 112, so that the peeling roller 110 can freely contact and separate from the surface of the plate cylinder 100. The home position of the plate discharging roller mechanism is when the peeling roller 110 is at the position shown by the two-dot chain line. At the timing when the plate cylinder 100 reaches the plate discharge position and stops, the clamper 106 is opened, and at this timing, the plate discharge roller mechanism swings from the home position, and the peeling roller 110 moves the surface of the plate cylinder 100, that is, the master 108. Abuts the surface.

[0004] The peeling roller 110 and the transport roller 112 rotate in the direction of the arrow, and when the end of the master 108 peeled by the peeling roller 110 is nipped at the nip between the rollers, the plate discharge roller mechanism continues to rotate the roller while maintaining the home position. The master 108 returned to the position and peeled off is transported to a plate discharge box (not shown). Master 1
The plate cylinder 100 is rotated clockwise in synchronization with the timing at which the end of the plate 08 is pinched by the nip portion, whereby the master 108 is continuously peeled off from the surface of the plate cylinder 100, and finally removed and discarded. You. Peeling of the end of the master 108 by the peeling roller 110 is possible because the coefficient of friction between the peeling roller 110 and the surface of the master 108 is larger than the coefficient of friction between the back surface of the master 108 and the mesh screen layer 104. Becomes In order to clarify the magnitude relationship between the friction coefficients and ensure the separation, the separation roller 110 is generally formed of a rubber material having a large friction coefficient. The configuration of the plate discharging roller mechanism is the same as that of the peeling roller 110 described above.
The configuration is not limited to the configuration of the transport roller 112 and the transport roller 112, and there are various configurations such as a configuration in which a peeling roller and a pair of transport rollers are combined.

[0005]

By the way, in this type of stencil printing machine, in order to ensure the separation of the end of the master 108, in other words, to eliminate the variation in the separation accuracy, the separation is ideal. In this case, control is performed such that the peeling roller 110 is brought into contact with the surface of the plate cylinder 100 for about 1.5 seconds after that, and the plate discharge roller mechanism is returned to the home position after this time has elapsed. In this case, as shown in FIG. 10, at the same time as the master 108 is peeled, the peel roller 110 is
Will be in direct contact with Mesh screen layer 10
The surface texture of No. 4 has high smoothness, and therefore, the frictional force between the rubber roller and the peeling roller 110 becomes extremely large, resulting in a high load, and the rotation speed of the peeling roller 110 decreases (in some cases, stops). A phenomenon has occurred.

When the rotation speed of the peeling roller 110 decreases,
The number of rotations of the transport roller 112 that is in pressure contact with this also decreases. Therefore, the speed at which the leading end of the peeled master 108 is conveyed, that is, the speed at which the master 108 is wound around the nip portion is extremely reduced, and as shown in FIG.
The plate discharge roller mechanism was returned to the home position in a state in which the leading end of No. 8 was insufficiently pinched, resulting in a "separation error" in which peeling was not performed after the leading end. In FIG. 10, a two-dot chain line display of the master 108 indicates an ideal winding / transporting state when the rotation speed does not decrease even after the peeling roller 110 contacts the mesh screen layer 104.

[0007] The present invention provides a stencil printing apparatus which can suppress the peeling error with high accuracy with a simple and low-cost configuration.
With that purpose.

The present invention considers that it is indispensable to keep the peeling roller in contact with the surface of the plate cylinder for a predetermined time from the viewpoint of increasing the peeling accuracy of the leading end of the master. Was intentionally reduced. Specifically, in a stencil printing machine that performs separation of a master wound around the outer peripheral surface of a plate cylinder by abutting a peeling roller located near the plate cylinder to discharge a plate,
A configuration is adopted in which a friction reducing member for reducing the contact friction force between the peeling roller and the outer circumferential surface of the plate cylinder is provided at a portion of the outer circumferential surface of the plate cylinder corresponding to the contact of the peeling roller.

According to a second aspect of the present invention, in the configuration of the first aspect, the friction reducing member has a surface property having a small contact area with the peeling roller and has a small friction coefficient. It has a configuration.

According to a third aspect of the present invention, in the configuration of the second aspect, the friction reducing member is a plain-woven sheet material.

According to a fourth aspect of the present invention, in the configuration of the second aspect, the friction reducing member is an embossed sheet material.

According to a fifth aspect of the present invention, in the configuration of the second aspect, the friction reducing member is a sheet material having a fine spherical body fixed to a surface thereof.

According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the sphere is a glass bead.
The configuration is adopted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, a schematic configuration of a stencil printing apparatus will be described with reference to FIG. The paper 4 loaded on the paper feed table 2 is pulled out from the uppermost one by the paper feed roller 6, and is separated from the separation roller 8 and the separation pad 1.
The sheets are separated and fed one by one by a friction separation action of zero. Thereafter, the sheet is fed to the nip portion between the plate cylinder 14 mainly composed of the porous support plate and the press roller 16 by the pair of registration rollers 12 at a predetermined timing. A clamper 18 is provided on a part of the outer peripheral surface of the plate cylinder 14, and the leading end of a master (not shown) produced by plate making means 20 based on read information of an original image is clamped by the clamper 18. Is wound on the outer peripheral surface of. An ink supply mechanism (not shown) is provided inside the plate cylinder 14, and the ink oozes out of the perforated portion of the master and is transferred to the paper 4 by the pressing action of the press roller 16. Thereby, an ink image is formed on the paper 4.

The printed sheet 4 is separated from the surface of the plate cylinder 14 by a separating means such as a separation claw (not shown), conveyed by a sheet discharge / transport unit 22 and discharged to a sheet discharge table 24. The paper discharge / transport unit 22 includes a transport belt 26, a suction fan 28, and the like. When printing of a predetermined number of sheets is completed by one plate (master), the plate discharging means 3
With 0, the master on the plate cylinder 14 is peeled and removed.

The plate discharging means 30, as shown in FIG. 2, mainly comprises a plate discharging roller mechanism 32 and a plate discharging box 34. The plate discharging roller mechanism 32 includes a peeling roller 36,
The transport roller 38 is configured to rotate in a direction indicated by an arrow. The plate cylinder 14 has a cylindrical porous support plate 40 formed of a stainless steel thin plate or the like, and a 1 to 1 wrapped around an outer peripheral surface of the porous support plate 40 and woven with a thin line of polyester or stainless steel. And a corresponding portion of the mesh screen layer 42 where the peeling roller 36 contacts,
A sheet-like friction reducing member 44 is provided. At the time of plate feeding, the master 46 is wound so as to cover the friction reducing member 44. As shown in FIG. 3, the friction reducing members 44 are individually provided corresponding to the respective peeling rollers 36. The area of the friction reducing member 44 is large enough to cover a range in which the friction reducing member 44 can reliably contact the peeling roller 36 even when an assembly error occurs in the manufacturing stage. In FIG. 3, the friction reducing member 44 is used.
The actual overlapping state of the sheet and the peeling roller 36 is shifted so as to be easily understood. The friction reducing member 44 has a surface property with a small contact area with the peeling roller 36 and is formed of a member having a small coefficient of friction. In this embodiment, a plain woven sheet made of synthetic fibers is used.

Next, the plate discharge roller mechanism 32 will be described with reference to FIG.
Will be described in detail. The transport roller 38 is fixed to a support shaft 46 rotatably supported at both ends by a side plate (not shown) of the apparatus main body at equal intervals in the axial direction. A drive gear 48 and a transmission gear 50 are fixed to the support shaft 46. In the vicinity of both ends of the support shaft 46, arm members 54, 54 are rotatably supported via bearings 56, 56. The drive gear 48 meshes with a pinion gear 60 fixed to an output shaft of a motor 58 attached to a side plate (not shown) of the apparatus main body.

Peeling roller 36 facing conveyance roller 38
Are round holes 54 formed at both ends in the arm members 54, 54.
The support shaft 62 is rotatably supported by a and is fixed at equal intervals in the axial direction. At both ends of the support shaft 62, retaining members (not shown) are provided.
4 is prevented from falling off. A transmission gear 64 that meshes with the transmission gear 50 is fixed to the support shaft 62.
The peeling roller 36 is formed of rubber, and is formed in a wheel shape having a gap 36a so as to be easily deformed in order to increase the frictional force on the master 46.
Due to the deformation of the outer peripheral surface, the contact area with the master 46 increases, and the frictional force increases accordingly. The peeling roller 36 and the transport roller 38 are always in pressure contact with each other due to the force of rubber deformation.

Each of the arm members 54 has a cam follower and a biasing means (not shown) at the upper end in FIG.
A notch is provided at each lower end so that a cam (not shown) provided on the apparatus main body can swing toward the plate cylinder 14 around the support shaft 46 by rotation. It is configured. Thereby, each peeling roller 36 is selectively positioned at the home position shown in FIG. 6 and the peeling position shown in FIG. As the swing mechanism and the positioning mechanism, for example, a technique disclosed in Japanese Utility Model Publication No. 2-274 can be adopted.

FIG. 2 shows a state in which the plate cylinder 14 is stopped at the plate discharging position, the clamper 18 is opened, the plate discharging roller mechanism 32 swings to the peeling position, and the leading end of the master 46 is slightly peeled. This shows the state of progress. Peeling roller 3
The friction coefficient between the outer peripheral surface of the master 6 and the front surface of the master 46 is larger than the friction coefficient between the rear surface of the master 46 and the friction reducing member 44, whereby the tip of the master 46 is separated by the rotation of the separation roller 36. Is done. When the peeling further proceeds, as shown in FIG. 5, the leading end of the master 46 is wound around the nip portion between the peeling roller 36 and the transport roller 38 in a bent state. In this case, the peeling roller 36 comes into contact with the friction reducing member 44 at the same time as the leading end of the master 46 moves from the surface of the friction reducing member 44, but as described above, the friction reducing member 44 is a plain woven sheet. The release roller 3 has uneven surface properties from its form.
The contact area with 6 is reduced. Further, since it is a synthetic fiber, the coefficient of friction is small, and therefore, the rotation speed of the peeling roller 36 does not decrease. Since the normal rotation of the peeling roller 36 and the transport roller 38 is maintained, the leading end of the master 46 is smoothly caught in the nip between the peeling roller 36 and the transport roller 38, and shifts to the transporting process.

As shown in FIG. 6, the plate discharge roller mechanism 32 is returned to the home position at the timing when the leading end of the master 46 is wound into the nip. Further, the plate cylinder 14 is driven to rotate clockwise in accordance with this timing, whereby the master 46 on the plate cylinder 14 is continuously peeled and conveyed by the plate discharge roller mechanism 32 and is accommodated in the plate discharge box 34. . In FIG. 6, the master 46 is displayed as a single line, and the plate cylinder 14 is also shown in a simplified manner.

By controlling the contact pressure of the peeling roller 36 against the plate cylinder 14, the peeling error can be prevented, but the structure becomes complicated and the price rises. With the configuration in which the friction reducing member 44 is provided as in the above embodiment, it is possible to prevent a peeling error with a simple configuration and at low cost.

In the above embodiment, a plain woven sheet is used as the friction reducing member 44. However, as shown in FIG. 7, a sheet material 70 formed of a material having a small coefficient of friction and embossed, or the surface of the embossed sheet material is used. A sheet material 74 to which the glass beads 72 are fixed by a method such as coating may be employed.

In the above-described embodiment, the plate discharge roller mechanism is described as including two rollers. However, the plate discharge roller mechanism may be similarly implemented in various configurations such as a type including a peeling roller and a pair of transport rollers. Can be.

[0025]

According to the present invention, a friction reducing member for reducing the contact frictional force between the peeling roller and the outer peripheral surface of the plate cylinder is provided at the portion of the surface of the plate cylinder where the peeling roller comes into contact. The peeling error due to the decrease or stop of the number of rotations can be prevented with a simple configuration and at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a stencil printing apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged front view of a main part showing an initial state of peeling.

FIG. 3 is a schematic side view showing a positional relationship between a peeling roller and a friction reducing member.

FIG. 4 is a schematic side view of a plate discharging roller mechanism.

FIG. 5 is an enlarged front view of a main part showing a state in which a peeling roller is in contact with a friction reducing member.

FIG. 6 is an enlarged front view of a main part showing a state in which the peeling roller has returned to the home position and peeling / transporting is in progress.

FIG. 7 is a sectional view of a friction reducing member according to another embodiment.

FIG. 8 is a sectional view of a friction reducing member according to another embodiment.

FIG. 9 is an enlarged front view of a main part showing an initial state of peeling in the related art.

FIG. 10 is a main part enlarged front view showing a state in which a peeling roller is in contact with the surface of a plate cylinder in the related art.

[Explanation of symbols]

 36 Peeling roller 44, 70, 74 Friction reducing member 46 Master 72 Glass beads

Claims (6)

[Claims] 1. A master wound around an outer peripheral surface of a plate cylinder,
In a stencil printing apparatus that abuts a peeling roller located in the vicinity of the printing drum and peels the plate, and performs plate discharging, at a contact corresponding portion of the peeling roller on the outer circumferential surface of the printing drum, the peeling roller and the outer circumferential surface of the printing drum. A stencil printing device comprising a friction reducing member for reducing the contact frictional force of the stencil printing machine. 2. A stencil printing apparatus according to claim 1, wherein said friction reducing member has a surface texture having a small contact area with said peeling roller and a small friction coefficient. . 3. A stencil printing apparatus according to claim 2, wherein said friction reducing member is a plain-woven sheet material. 4. A stencil printing apparatus according to claim 2, wherein said friction reducing member is an embossed sheet material. 5. The stencil printing apparatus according to claim 2, wherein said friction reducing member is a sheet material having a fine spherical body fixed on a surface thereof. 6. The stencil printing apparatus according to claim 5, wherein said spherical body is a glass bead.