JP2895635B2 - Plate cylinder for 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 plate cylinder for a stencil printing machine which performs printing by loading a perforated stencil sheet.

[0002]

2. Description of the Related Art Generally, in a stencil printing machine of this type, a stencil sheet is wound on an outer peripheral surface of a cylindrical plate cylinder having a porous structure, and printing paper is pressed on a plate cylinder surface (stencil surface) by a pressing roller. Printing is performed by causing ink to ooze out of the stencil sheet and transferred to printing paper by a built-in ink supply / applying means.

Here, as a method of holding a stencil sheet, a plate cylinder is provided with a clamper, and the leading end of the stencil sheet is clamped. However, the impact at the time of pressing roller contact,
The stencil sheet is pulled in the direction opposite to the rotation direction of the plate cylinder due to the load during the rotation of the rollers, the load on the paper feeding unit when the printing paper is transported between the plate cylinder and the pressing roller, and the like. Therefore, when a large amount of printing is performed, the stencil sheet gradually comes off from the clamper, which may result in a printed matter that cannot be adopted because it is shifted from a predetermined position.

As a countermeasure, a clamper of a type in which a stencil sheet is held between a rubber magnet and a metal plate,
There is a method of increasing the magnet magnetic force.

Further, as shown in Japanese Utility Model Laid-Open Publication No. 61-31830, there is a locking device in which a high friction member is provided on one side of a clamper so that a stencil sheet does not come off.

[0006]

However, according to the method of increasing the magnet magnetic force of the clamper, the holding force increases, but the clamper portion becomes large, and a large force is required when opening and closing the clamper. It will be.

Further, in the case of the locking device described in the above-mentioned publication, since the stencil sheet is forcibly stopped, there is a disadvantage that the stencil sheet is broken or jammed by being caught by a friction member.

[0008]

A printing paper press-contacted by a pressing means including a press roller which can be freely separated and held onto a stencil sheet held by a clamper and loaded on an outer peripheral surface thereof is provided with a built-in ink supply coating. In the cylindrical plate cylinder for a stencil printing machine having a porous structure to be printed by the means, a friction increasing portion is formed near the contact start position on the outermost periphery with which the pressing roller contacts.

[0009]

When the pressing roller comes into contact with the outer peripheral surface via the printing paper and the stencil sheet each time printing is performed, a friction increasing portion is formed at that portion. A large frictional force is secured in between, so that displacement of the base paper is less likely to occur, and no excessive force is applied. In the portion where printing is actually performed, the ink is supplied through the opened porous portion, so that the frictional force between the plate cylinder and the stencil sheet is sufficient due to the adhesive force of the ink, and no displacement of the sheet occurs. As a result, it is possible to keep the base paper as a whole without any deviation, and it is possible to obtain a good printed matter.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. First, a plate cylinder 1 formed in a hollow cylindrical shape and driven to rotate clockwise is provided. The plate cylinder 1 is provided with a clamper 3 for clamping and holding the leading end of the stencil paper 2 at a part of the outer peripheral surface thereof, and the stencil paper 2 is loaded in a wound state on the outer peripheral surface. Here, the vicinity where the clamper 3 is provided is formed as a non-opening portion 1a.
The portion corresponding to the image area of the stencil sheet 2 is formed as an aperture 1b having a porous structure. In addition, an ink supply / application unit 4 is built in the plate cylinder 1. The ink supply and application means 4 includes an ink roller 5 in contact with the inner peripheral surface of the plate cylinder 1.
And an ink supply pipe 7 for supplying the ink 6 onto the ink roller 5, and a doctor roller 8 almost in contact with the ink roller 5 for regulating the amount of the supplied ink 6 (ink layer thickness). A pressing means 9 is provided outside the plate cylinder 1. The pressing means 9 includes a support shaft 10
The pressure roller 12 is supported by an arm 11 that is rotatable about the ink roller 5 and comes into contact with and separates from the outer peripheral surface at a predetermined timing at an external position facing the ink roller 5. Further, a pair of registration rollers 14 for transporting the printing paper 13 at a predetermined timing to a printing position on the outer peripheral surface of the plate cylinder 1 by the ink roller 5 are provided.

In such a general configuration, the leading end of the stencil sheet 2 on which a required image is formed by a thermal head or the like is held by the clamper 3. The clamper 3 may be a known one such as a rubber magnet type. Then, the stencil sheet 2 is loaded on the outer peripheral surface of the plate cylinder 1 by rotating the plate cylinder 1 clockwise. In these operations, the pressing roller 12 waits at a position away from the plate cylinder 1. Then, when a print instruction is issued, the printing paper 13 is fed one by one from the paper supply unit, and the registration roller 14 is synchronized with the plate cylinder 1 (accordingly, the image of the stencil sheet 2), and the printing unit (ink roller 5). (Directly below).
When the supply of the printing paper 13 is detected by the paper detecting means (not shown), the standby state is released and the pressing roller 1 is released.
2 is displaced upward, and the printing paper 13 is pressed against the stencil sheet 2 (contact state with the plate cylinder 1). FIG. 1 shows such a contact start state of the pressing roller 12.

When the plate cylinder 1 rotates clockwise in such a state, the ink roller 5 moves clockwise while the stencil paper 2 and the printing paper 13 are pressed by the pressing roller 12. , Ink 6 on ink roller 5
Oozes out onto the printing paper 13 through the holes of the opening portion 1b of the plate cylinder 1 and the holes of the stencil sheet 2, and is transferred and printed. When the printing proceeds and the non-opening portion 1a arrives, the pressing roller 12 separates from the surface of the plate cylinder 1, avoids the clamper 3, and enters a standby state for supplying the next printing paper 13. Thereafter, the same operation is repeated every time printing is performed.

Here, as shown in FIG.
Since the pressing force is insufficient at the portion where the stencil begins to contact the plate cylinder 1, the frictional force between the stencil sheet 2 and the plate cylinder 1 is low, and the stencil sheet is likely to be displaced. In particular, as the press roller 12 repeatedly contacts and separates during printing, the displacement of the base paper gradually increases, and there is a possibility that the base paper slips out of the clamper 3. Therefore, in this embodiment, the pressing roller 12 as shown in FIG.
The friction increasing portion 15 is formed by a high friction member on the surface of the non-opening portion 1a of the plate cylinder 1 in the vicinity of the contact start position where the contact is made. Therefore, when the pressing roller 12 comes into contact with the plate cylinder 1, a large frictional force is secured between the stencil sheet 2 and the plate cylinder 1, and the displacement of the base paper when the pressing roller comes into contact is reduced as much as possible. In the multi-hole portion 1b for actual printing,
The stencil sheet 2 and the plate cylinder 1 are formed by the adhesive force of the supplied ink 6.
And a sufficient frictional force is secured between them, so that even if a load is applied to the printing paper 13 on the paper supply unit side, the displacement of the base paper becomes small.

The high friction member forming the friction increasing portion 15 may be sandpaper # 120 to # 320. Also,
The use of a soft roller as the pressing roller 12 provided better results. By the way, 120
When the amount of displacement of the stencil sheet 2 when 2,000 sheets were printed at a printing speed of sheets / minute was measured, the friction increasing portion 15 was measured.
Is 5 to 12 mm in the case where the friction increasing portion 15 is not provided as in the present embodiment.
It was about 0.5 mm.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those described in the above embodiment are denoted by the same reference numerals. The present embodiment is applied to the plate cylinder 1 having a mesh screen 16 mounted on the outer peripheral surface thereof, in which a friction increasing portion 15 is provided near the pressing roller contact start position P on the mesh screen 16. . FIG. 3 is a developed view schematically showing a plate cylinder 1 having such a friction increasing portion 15 on a mesh screen 16.

[0016]

According to the present invention, as described above, the friction increasing portion is formed near the contact start position of the outermost periphery of the plate cylinder with which the pressing roller contacts, so that the pressing roller is formed on the outer peripheral surface via the printing paper and the stencil sheet. Each time it comes into contact with the upper part, a large frictional force is secured between the plate cylinder and the stencil sheet in that part without applying excessive force such as pulling, and it is possible to make the base sheet less likely to shift, As a whole, keep the base paper free from deviation,
It is possible to obtain a good printed matter without any displacement.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a second embodiment of the present invention.

FIG. 3 is a development view of a plate cylinder.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plate cylinder 2 stencil sheet 3 ink supply / application means 9 pressing means 12 pressing roller 13 printing paper 15 friction increasing portion

Claims (1)

(57) [Claims] 1. A printing paper, which is brought into pressure contact with a stencil sheet held by a clamper and loaded on an outer peripheral surface thereof by a pressing means including a pressing roller capable of coming and going, is printed by a built-in ink supply / applying means. A cylindrical cylinder for a stencil printing press having a porous structure, wherein a friction increasing portion is formed near a contact start position on the outermost periphery with which the pressing roller contacts.