JPH0254939B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum cylinder type printing machine that prints an image on an original plate onto a photosensitive material while the original plate and the photosensitive material are wound around a cylinder.

[Conventional technology]

When a photosensitive material such as a printing plate that has been printed in close contact with an original plate in a flat state is mounted on a cylindrical plate cylinder of a printing machine, the photosensitive material is bent into a cylindrical shape, and the thickness of the photosensitive material is , whose image dimensions extend in the circumferential direction of the plate cylinder relative to the image dimensions of the original.

Therefore, when printing photosensitive materials used in printing where the absolute dimensional accuracy of the printed image is important, such as printing printed wiring boards, it is necessary to correct the circumferential dimension at the time of printing, etc. There is.

An example of an apparatus that prints an image by changing only the dimension in one direction is disclosed in Japanese Patent Publication No. 58-52571 and U.S. Pat. There is an apparatus that performs slit exposure while relatively moving at slightly different speeds.

[Problem that the invention seeks to solve]

In the apparatuses disclosed in Japanese Patent Publication No. 58-52571 and US Pat. In the case of a low-sensitivity photosensitive material such as the intaglio printing plate disclosed in the publication, the amount of exposure is insufficient and efficient printing cannot be performed.

Therefore, the image on the original plate is first reduced in size in one direction and printed on a photosensitive material such as a sensitive silver halide film, and then the film is transferred to a photosensitive material such as a printing plate using a normal contact printing machine. Then, it is necessary to print again, which not only increases the number of work steps, but also requires additional light-sensitive materials such as silver halide film.Furthermore, due to the increase in work steps, the accuracy of the image becomes unstable. becomes.

Therefore, for example, using a cylindrical printing device disclosed in Japanese Utility Model Application Publication No. 49-86105, a photosensitive material such as a printing plate and an original plate are placed in a cylindrical member having a diameter corresponding to the plate cylinder of a printing press. It is also possible to prevent the image size from elongating in the circumferential direction when the photosensitive material is wound around the plate cylinder by wrapping the photosensitive material in an overlapping state and performing printing. but,
When such a device is used, it is not only necessary to prepare a plurality of cylindrical members with different diameters to which photosensitive materials such as printing plates are mounted, depending on the dimensions of the plate cylinder of the printing press. There are problems as described below.

When wrapping the original plate and photosensitive material around a cylindrical member for printing, place the film surface of the photosensitive material on the outside.
Furthermore, by placing the film surface (image area) of the original on the inside, printing is performed with both film surfaces in close contact with each other.

At this time, the film surface of the photosensitive material extends in the circumferential direction as described above, but the film surface of the original plate (image area)
Since it is located inside the original plate, it will shrink in the circumferential direction depending on the thickness of the original plate. Therefore, in order to correct this shrinkage of the original plate, it is necessary to print the cylindrical member with a diameter slightly larger than the diameter of the plate cylinder in the printing press, depending on the thickness of the original plate. However, if the thickness of the original plate differs, the amount of shrinkage in the image area will differ.
It is necessary to change the diameter of the cylindrical member not only to correspond to the diameter of the plate cylinder, but also to correspond to the thickness of the original plate.

Furthermore, the size of the image on the printing substrate that is actually printed depends on factors such as the area of the pattern in the image, the viscosity of the ink, and the elasticity of the printing plate. Due to the difference, there is a slight change in the circumferential direction, so it is impossible for the above-mentioned device to cope with such a slight dimensional change.

In order to solve the above-mentioned problems, the inventors of the present invention
An attempt was made to develop a printing machine with a cylinder with variable diameter.

As a means for changing the diameter of the cylinder, for example, as disclosed in Japanese Utility Model Publication No. 59-24211, a plurality of beams are installed between rings having tapered surfaces facing each other, and the distance between the rings is changed. Mechanisms are known for changing the diameter of a cylinder formed by a plurality of beams.

However, since the outer peripheral cross section of the cylinder formed by this mechanism is not circular but polygonal, it is impossible to use this in a printing machine that requires precision.

[Means for solving problems]

As a means for solving the above-mentioned problems, the present invention provides a pair of flange members having tapered surfaces facing each other and supported by a rotatable shaft, and a drive for driving the rotatable shaft. means and 1
means for changing the spacing between the pair of flange members;
A plurality of drum pieces installed between the pair of flange members, an elastic sheet arranged on the outer peripheral surface of the plurality of drum pieces, a translucent sheet arranged outside the elastic sheet, and an elastic sheet. and a packing disposed to form an airtight chamber between the light-transmitting sheet and the light-transmitting sheet, an exhaust means for exhausting air from the air-tight chamber, and an exposure means for emitting light toward the light-transmitting sheet. A vacuum cylinder type printing machine with variable diameter is provided.

[Effect]

By changing the spacing between a pair of flange members, an elastic sheet disposed on the outer circumferential surface of a plurality of drum pieces installed between them and a translucent sheet disposed on the outside of the elastic sheet are formed. The diameter of the airtight chamber changes depending on the sheet, so after setting this diameter to an appropriate value, the original plate and photosensitive material are brought into close contact with each other in the airtight room and printed, thereby creating an image on the original plate in the circumferential direction. Only the necessary dimensions can be corrected and printed onto photosensitive materials.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a diameter cylinder type printing machine according to the present invention will be described based on the accompanying drawings.

Fig. 1 is a perspective view of the cylinder type printing machine, Fig. 2 is a schematic side view of Fig. 1 with the side plate removed,
FIG. 3 is a partially longitudinal front view showing the diameter changing mechanism of the cylinder type printing machine, and FIG. 4 is a partially longitudinal side view thereof.

In these figures, reference numeral 12 designates a pair of flange members having tapered surfaces 14 facing each other, and are screwed and supported by a shaft 20 having a right-handed threaded portion 16 and a left-handed threaded portion 18 at both ends, respectively.

The shaft 20 is supported by bearings 22 and 24, and
It has a ventilation section 26 inside. This ventilation section 26 is connected to a vacuum pump (not shown) via a rotary type joint 28. In addition, the shaft 20
One end is connected to a motor 34 via a sprocket 30, a chain (not shown), and a sprocket 32, and is rotated by the drive of the motor 34.

36 is a plurality of drum pieces installed between a pair of flange members 12 via a sliding member 38, and a cylinder 50 is formed by these drum pieces 36 and the pair of flange members 12. There is.

A blanket 40 made of an elastic member such as rubber is disposed on the outer peripheral surface of the drum piece 36. By fixing the blanket 40 to each drum piece 36 with screws 42, the drum piece 3
6 are connected to each other. In addition, the drum piece 36
In order to make the connection more secure, the drum piece 36
may be fixed to each other at adjacent long side regions using flexible adhesive tape.

The plurality of connected drums 36 are urged toward the axis by a ring-shaped spring member 48. In order to prevent the drum pieces 36 from shifting in the direction of the shaft 20 by engaging a flange 44 disposed on the shaft 20 with all or some of the plurality of drum pieces 36. An L-shaped metal fitting 46 is fixed thereto. In addition, at one location each on the tapered surfaces 14 of the pair of flange members 12,
The drum piece 3 engaged with the sliding member 38 and connected
Stop member 5 for regulating the circumferential position of one end of 6
2 are arranged.

56 is an exhaust hole provided at one end of the bracket 40, which connects the ventilation portion 26 of the shaft 20 and the nozzle 58,
60 and a coiled ventilation pipe 6 whose illustration is partially omitted.
It is connected by 2.

54 is a packing disposed on the surface of the blanket 40; 64 is a transparent sheet disposed on the outer periphery of the blanket 40;
4 and the blanket 40 form an airtight chamber 66.

Although not shown, the transparent sheet 64 is configured to be attachable to and detachable from the blanket 40 using a flat fastener such as magic tape (registered trademark).

68 is connected to 1 by a screw 72 via a spring 70.
A detent member is supported on the side surfaces of the pair of flange members 12 so as to be movable between the positions indicated by the solid line and the broken line shown in FIG. It is a locking nut that screws together.

The pair of flange members 12 are fitted with lock nuts 76.
is tightened, the rotation prevention member 68 is moved to the fourth
By positioning it at the position indicated by the broken line shown in the figure, it rotates together with the shaft 20, and when the lock nut 76 is loosened, the rotation prevention member 68 can be moved to the fourth position.
By engaging the stay 74 provided on the main body at the position indicated by the solid line shown in the figure, the spacing is changed by rotating the shaft 20.

When the distance between the pair of flange members 12 is the largest, the cylinder 50 formed by the drum piece 36 is at the position A shown in FIGS. 3 and 4.
It has the smallest diameter at position B, and has the largest diameter at position B when the spacing between the flange members 12 is the smallest. At this time, at position A, the plurality of drum pieces 36 are attached to the cylinder 50.
However, at position B, the portion 8 of the entire circumference of the cylinder 50 where the drum piece 36 is not
There are 4.

Reference numeral 78 denotes a light source for printing that generates ultraviolet light, such as a metal halide lamp or a mercury lamp (FIG. 2). The light emitted from the light source 78 is irradiated through the mirror 80 through the exposure opening 82 toward the transparent sheet 64 on the outer periphery of the cylinder 50 .

Next, the printing operation in this apparatus will be explained.

First, the lock nut 76 is loosened, and the detent member 68 is engaged with the stay 74 at the position shown by the solid line in FIG. In this state, by rotating the shaft 20 by driving the motor 34 and changing the distance between the pair of flange members 12, the diameter of the cylinder 50 formed by the plurality of drum pieces 36 is set by this device. The diameter is set to an appropriate value (hereinafter referred to as the "optimal diameter") depending on the photosensitive material such as a printing plate that is used for printing.

Here, the optimum diameter is a value obtained by adding a small dimension for correcting the amount of shrinkage of the original plate image to the diameter of the printing press plate cylinder, and also taking into account corrections based on printing conditions based on ink, printing plate, etc.

Next, a photosensitive material such as a printing plate is positioned on the blanket 40, and an original plate is positioned on top of the blanket 40 and fixed with tape or the like, and the lock nut 76 is tightened, and the locking member 68 and the stay 74 are engaged with each other. Solve. In this state, a cylinder 50 having an optimum diameter is formed.

Next, one end of the transparent sheet 64 is fixed to the end of the blanket 40 using a flat fastener or the like, and while rotating the cylinder 50 together with the shaft 20 at a low speed, the transparent sheet 64 is wrapped around the original plate and the photosensitive material. The cover forms an airtight chamber 66.

In this state, the air in the airtight chamber 66 is removed from the exhaust hole 56.
The air is further evacuated, the airtight chamber 66 is evacuated, and the original plate and the photosensitive material are brought into close contact with each other.

In this state, the cylinder 50 is
While rotating at 15 rpm until the desired printing effect is obtained, the light source 78 is turned on to print the photosensitive material.

〔Effect of the invention〕

Since the one-way shortening printing machine of the present invention is configured as described above, it is possible to print the image of the original plate directly onto the photosensitive material by accurately correcting the image by any desired dimension in the circumferential direction. Can be done.

Furthermore, since a plurality of drum pieces 36 are used when changing the diameter of the cylinder 50 using the tapered surface 14 of the flange member 12, the cylinder formed by the drum pieces 36 is In contrast, it has sufficient strength, and in the circumferential direction, it has flexibility that follows the tapered surface 14, making it possible to perform printing with high precision.

[Brief explanation of the drawing]

The drawings are views showing embodiments of the present invention, and FIG. 1 is a perspective view of a cylinder type printing machine, and FIG.
The drawings are a schematic side view of FIG. 1 with the side plate removed, FIG. 3 is a partially longitudinal front view showing the diameter changing mechanism of the printing machine, and FIG. 4 is a partially longitudinal side view. 12...flange member, 14...tapered surface,
16... Right-hand threaded part, 18... Left-hand threaded part, 20...
Shaft, 36...Drum piece, 40...Rubber sheet, 4
8... Spring member, 54... Packing, 56... Exhaust hole, 64... Transparent sheet, 78... Light source, 80
... Mirror, 82 ... Exposure opening.

Claims (1)

[Claims] 1. A pair of flange members having tapered surfaces facing each other and supported by a rotatable shaft, a driving means for driving the rotatable shaft, and a distance between the pair of flange members. a plurality of drum pieces installed between the pair of flange members; an elastic sheet disposed on the outer peripheral surface of the plurality of drum pieces;
a translucent sheet placed outside the elastic sheet;
It is equipped with packing arranged to form an airtight chamber between the elastic sheet and the translucent sheet, an exhaust means for exhausting air from the airtight chamber, and an exposure means for emitting light toward the translucent sheet. A vacuum cylinder type printing machine with variable diameter. 2. Connecting multiple drum pieces to each other,
The variable diameter vacuum cylinder type printing machine according to claim 1, further comprising a biasing means for biasing the drum piece toward the axis. 3 Threaded parts with opposite thread directions are formed on both ends of the shaft, a pair of flange members are screwed into the threaded parts, and the shaft is rotated relative to the flange members. A variable diameter vacuum cylinder type baking machine according to claim 1 or 2, wherein the distance between the pair of flange members can be changed by changing the distance between the pair of flange members.