JPH0699652A - Plate cylinder of rotary stencil printer - Google Patents

Abstract

PURPOSE:To enhance an adhesion of a plate cylinder to an ink roller to reduce defective printing. CONSTITUTION:In the arrangement of a large number of ink through holes provided in a hole part of a plate cylinder, a hole pitch in a rotating direction A is determined to be different from a hole pitch in a generating line direction B. Furthermore, a hole size or pitch varies in the generating line direction from the center part of the plate cylinder to each end thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate cylinder having a porous structure in a rotary stencil printing machine.

[0002]

2. Description of the Related Art A magnet piece constituting a clamp is attached along a generatrix of a part of the outer peripheral surface of a plate cylinder used in a rotary stencil printing machine, and a generatrix of the plate cylinder is provided at a position facing the magnet piece. A clamp piece that is rotatable between a first position that is attracted to the magnet piece and a second position that is separated from the magnet piece about a pivot that is parallel to
A base paper locking device in which a thin layer having high frictional resistance is provided on the surface of the clamp piece facing the magnet piece is disclosed in Japanese Utility Model Laid-Open No. 61-31830.
It is described in.

With this structure, the stencil sheet holding force of the clamp piece is increased, the stencil sheet is prevented from slipping out of the clamp piece, and the deviation of the printed image is prevented.

[0004]

In the rotary stencil printing machine having the above-mentioned structure, when printing is performed, the ink supplied to the outer peripheral surface of the ink roller comes into contact with the inner peripheral surface of the plate cylinder so that the ink is discharged from the plate cylinder opening portion. Although it exudes, there is a slight gap between the inner peripheral surface of the plate cylinder and the ink roller, and when pressing the plate cylinder with a press roller, it is difficult for both ends to adhere to each other compared to the center of the ink roller. In some parts, the ink supply becomes unstable, and as a result, the image density decreases. Further, the pitch of the holes of the plate cylinder opening portion is the same in the generatrix direction and the rotating direction of the plate cylinder, and the plate cylinder has a structure that is easily bent in the generatrix direction and the rotating direction. However, if the plate cylinder is liable to bend in the direction of rotation, press the printing roller against the plate cylinder to perform printing, and press the printing roller to rotate the press roller and pull out the printing sheet from the paper feed unit. The peripheral speed difference of the plate cylinder acts on the plate cylinder as a load due to the force of shearing the ink at each contact surface, and the plate cylinder opening is deformed and expanded due to the force applied to the plate cylinder in the direction opposite to the rotational direction. Take shape. Further, the stencil sheet is clamped at its tip by the clamp piece of the plate cylinder, and the above deformation occurs in a state of being pressed against the plate cylinder by the press roller.
Trying to get out of the clamp piece. However, since the stencil sheet is held by the high-friction member, the stencil sheet cannot withstand the pulling force, and is damaged or stretched, resulting in defective printing.

[0005]

The invention according to claim 1 is
In a rotary stencil printing apparatus, a cylindrical plate cylinder having a porous structure, which is rotated by mounting a stencil sheet on the outer peripheral surface thereof, and a rotatable ink roller arranged so as to contact the outer peripheral surface with the inner peripheral surface of the plate cylinder. And an ink supply means for supplying ink to the outer peripheral surface of the ink roller, and a press roller for pressing the printing paper onto the stencil sheet. The printing paper is pressed by the press roller to open the plate cylinder. In a rotary stencil printing apparatus for performing printing by exuding from the holes and the perforations of the base paper, the pitch of the holes on the plate cylinder generatrix of the plate cylinder openings is made larger than that in the rotational direction. .

According to a second aspect of the present invention, in the plate cylinder according to the first aspect, the size of the holes of the plate cylinder is set so as to extend from a central portion of the plate cylinder to both end portions of the plate cylinder. It is characterized by gradually increasing as it goes.

According to a third aspect of the present invention, in the plate cylinder of the first aspect, the pitch of the holes of the plate cylinder openings is further increased from the central portion of the plate cylinder toward both ends on the generatrix of the plate cylinder. It is characterized by gradually decreasing according to

According to a fourth aspect of the present invention, in the plate cylinder of the first aspect, the ink roller is rotated at substantially the same speed as the peripheral speed of the inner peripheral surface of the plate cylinder.

[0009]

According to the first aspect of the invention, the pitch of the plate cylinder openings on the plate cylinder generatrix is made larger than that in the rotational direction, so that the plate cylinder openings are easily bent in the generatrix direction. , It becomes difficult to bend in the rotation direction.

According to the second aspect of the invention, the size of the plate cylinder opening on the plate cylinder generatrix is gradually increased from the center of the plate cylinder toward both ends. Both ends of the part are easily bent.

According to the third aspect of the invention, the pitch of the holes on the plate cylinder generatrix of the plate cylinder is gradually reduced from the central part of the plate cylinder toward both ends thereof. Both ends of the plate cylinder opening are easily bent.

According to the fourth aspect of the present invention, the peripheral speed of the ink roller is set to be substantially the same as the peripheral speed of the inner peripheral surface of the plate cylinder. Therefore, the plate cylinder shears the ink with the ink roller. The load generated when rotating is reduced.

[0013]

EXAMPLE Referring to FIG. 1, a cylindrical plate cylinder 1 having a porous structure.
Is rotatably supported by the frame of the printing apparatus, and the ink supply pipe 3 that also serves as the rotation axis of the plate cylinder 1 is fixed to the frame. A clamp piece 13 rotatable about a shaft 18 is provided on a part of the outer periphery of the plate cylinder 1, and a magnet 12 is fixed to the clamp piece 13 to form a stencil sheet 2.
The tip of the plate is held between the plate cylinder 1 and the plate.
The plate cylinder 1 has a shape in which the front edge and the side edge are non-perforated, and the plate cylinder aperture 1a is provided with a large number of circular holes. The clamp piece 13 is provided in the non-opening portion. An ink roller 4 which is driven to rotate in the same direction as the plate cylinder 1 is arranged in the plate cylinder 1, and a slight gap is formed between the inner peripheral surface of the plate cylinder 1 and the outer peripheral surface of the ink roller 4. Is provided. The press roller 8 is disposed at a position opposed to the ink roller 4 via the plate cylinder 1 so as to come in contact with and separate from the outer peripheral surface of the plate cylinder 1. Only when pressed through 7, the gap is lost and the two come into contact with each other. Central shaft 14 of ink roller 4
A drive gear 15 is provided at one end of the. Further, a motor gear 17 is disposed on the shaft portion of the motor 16, and by engaging it with the drive gear 15, the rotational force of the motor 16 is transmitted to the ink roller 4. A doctor roller 5 is installed at a position facing the ink roller 4. A slight gap is provided between the outer peripheral surface of the ink roller 4 and the outer peripheral surface of the ink roller 4, and when the printing ink supplied to the ink reservoir 6 passes through the gap, a thin film is formed on the outer peripheral surface of the ink roller 4. Adhere to. The printing paper 7 is fed after being separated one by one by the paper feed roller 10 and the separation roller 11, and temporarily waited by the registration roller 9 and then fed between the stencil sheet 2 and the press roller 8 at a timing. . Then, the press roller 8 presses the printing paper 7 against the stencil sheet 2, and conveys the printing paper 7 while rotating around the plate cylinder 1. The press roller 8 is separated from the stencil sheet 2 at a predetermined timing and is in a standby state, and when the printing paper 7 is fed, the above-mentioned contact / separation operation is repeated.
The separation roller 11 presses the paper feed roller 10 via the printing paper 7, and restricts the paper other than the printing paper 7 from being fed. The printing paper 7 is peeled from the stencil sheet 2 by a peeling nail (not shown), and is discharged to a dedicated tray.
Printing is performed by the series of operations described above. Plate cylinder opening 1
As shown in FIG. 2, the large number of circular holes formed in a are arranged so that the hole pitch A in the rotational direction indicated by the arrow is larger than the hole pitch B in the generatrix direction of the plate cylinder. An array of holes is provided to make a rectangle.

(Embodiment 2) FIG. 3 shows another embodiment of the present invention. This embodiment shows the arrangement of holes formed in the plate cylinder hole portion 1a of the plate cylinder 1 shown in FIG. 1, and two pairs of hole rows having the pitch shown in FIG. 2 are combined to form a rhombic shape. It was done.

(Embodiment 3) FIG. 4 shows another embodiment of the present invention. This embodiment shows an arrangement of holes formed in the plate cylinder opening portion 1a of the plate cylinder 1 shown in FIG. 1, and the diameter of the holes is set in the generatrix direction of the plate cylinder 1 from the center to both ends of the plate cylinder. It is gradually enlarged as it goes.

(Embodiment 4) FIG. 5 shows another embodiment of the present invention. This embodiment shows the arrangement of the holes formed in the plate cylinder opening portion 1a of the plate cylinder 1 shown in FIG. 1, and the pitch of the holes on the generatrix side is the central portion of the plate cylinder in the generatrix direction of the plate cylinder 1. It is gradually reduced toward both ends.

[0017]

According to the first aspect of the present invention, it is possible to prevent deformation of the plate cylinder apertures, thereby preventing damage and deformation of the stencil sheet, and reducing printing defects. According to the second aspect of the invention, there is an effect that the plate cylinder edge portion can be brought into close contact with the ink roller, whereby a printed matter having a constant density can be obtained. According to the invention described in claim 3, there is an effect that the plate cylinder end portion can be brought into close contact with the ink roller, whereby a printed matter having a constant density can be obtained.

According to the fourth aspect of the present invention, it is possible to prevent the plate cylinder apertures from being deformed, thereby preventing the stencil sheet from being damaged or deformed, and reducing printing defects.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a rotary stencil printing machine adopting an embodiment of the present invention.

FIG. 2 is a plan view of a plate cylinder hole portion of the rotary stencil printing machine showing the first embodiment of the present invention.

FIG. 3 is a plan view of a plate cylinder aperture of a rotary stencil printing machine showing a second embodiment of the present invention.

FIG. 4 is a plan view of a plate cylinder opening portion of a rotary stencil printing machine showing a third embodiment of the present invention.

FIG. 5 is a plan view of a plate cylinder hole portion of a rotary stencil printing machine showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Cylindrical plate cylinder 1a Plate cylinder aperture 2 Plate making base paper 3 Ink supply pipe 4 Ink roller 5 Doctor roller 6 Ink reservoir 7 Printing paper 8 Press roller 9 Registration roller 10 Paper feed roller 11 Separation roller 12 Magnet 13 Clamp piece 14 Center Shaft 15 Drive Gear 16 Motor 17 Motor Gear 18 Shaft

Claims (4)

[Claims] 1. A cylindrical plate cylinder having a porous structure which is rotated by mounting a stencil sheet on an outer peripheral surface thereof, and a rotatable ink roller which is arranged so as to contact the outer peripheral surface with the inner peripheral surface of the plate cylinder. An ink supply means for supplying ink to the outer peripheral surface of the ink roller, and a press roller for pressing the printing paper against the stencil sheet. The printing paper is pressed by the press roller to open the plate cylinder. In a rotary stencil printing apparatus for performing printing by bleeding from the plate portion and the perforation portion of the base paper, the pitch of the holes in the rotation direction of the plate cylinder opening portion is made larger than that on the plate cylinder busbar. Plate cylinder in a digital stencil printer. 2. The size of the hole of the plate cylinder opening is gradually increased from the center of the plate cylinder toward both ends on the generatrix of the plate cylinder. A plate cylinder of the rotary stencil printer described. 3. The plate pitch of the plate cylinder apertures is gradually reduced from the center of the plate cylinder toward both ends on the generatrix of the plate cylinder. Plate cylinder of a rotary stencil printer. 4. The ink roller is rotated at substantially the same speed as the peripheral speed of the inner peripheral surface of the plate cylinder.
A plate cylinder of the rotary stencil printer described.