JPH0839751A - Plate-making device for stencil printing device and master to be used therefor - Google Patents

Abstract

PURPOSE:To convey a master by preventing generation of wrinkle in the master even when a master which substantially consists of only a thermoplastic resin film is used. CONSTITUTION:In a plate-making device for a stencil printing device, a master 1a wound in a roll is pinched with pressure by a thermal head 5 which constitutes a plate-making means 3 and has an overall width the same as that of the master 1a or more and a platen roller 4 so as to make a plate by heat melt punching. A convey means 6 consisting of a pair of rollers arranged at the downstream side of the master conveying direction of the plate-making means 3 conveys a master 1b, whose plate-making is completed by the plate- making means 3, by pinching and stretching it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate making apparatus of a stencil printing apparatus for winding and printing a master punched with a heating element such as a thermal head, and a master used in this stencil printing apparatus.

[0002]

2. Description of the Related Art Digital thermal stencil printing has been known as a simpler printing method. This is because the master is contacted with a thermal head in which fine heating elements are arranged in a line,
By conveying the master while energizing the heating element in a pulsed manner, the master is heated and melted and perforated based on the image information, and then this pre-mastered master is automatically conveyed to the outer peripheral surface of the cylindrical plate cylinder automatically. The press roller continuously presses the printing paper against the wrapped and master-made master, and the ink passes from the perforated portion of the master and then transferred to the printing paper to form a printed image. .

The master conventionally used for this stencil printing is made of a thermoplastic resin film (thickness of about 1 to 2 .mu.m) such as a thin polyester, and a porous support made of Japanese paper, synthetic fibers, or a mixture of Japanese paper and synthetic fibers. It has a laminated structure in which objects are stuck together.

At the time of printing, the ink passes through fibers such as Japanese paper which is a porous support of the master, and therefore there is a portion where the fibers are intricately entangled (a lumped portion) or perforation occurs. When the fiber has crossed the part, there is a problem that the transmission of the ink is obstructed, a fiber pattern appears in the solid part, the fine line is cut or blurred, that is, a so-called fiber grain is generated. .

Therefore, printing is carried out using a master having a thin porous support such as Japanese paper, which causes fibers, or a master consisting essentially of a thermoplastic resin film without using the porous support. , Attempts have been made to reduce defects due to fiber grain.

[0006]

However, the apparent strength of the conventional master is taken care of by the porous support, and the master having a thin porous support or a master substantially consisting of a thermoplastic resin film is used. When printing is performed, the strength (back) of the master is significantly reduced because the thermoplastic resin film is thin, and the transport of the master becomes unstable.

In a conventional stencil printing machine, generally, a master wound in a roll shape is conveyed while being pressed and sandwiched by a platen roller or a conveying means. When transporting a high-strength master having a conventionally used porous support, by using a shredded roller or a roller whose width is slightly shorter than the width of the master, as a transport means,
Even if the master stretches locally differently, the master itself has strength so that waviness is suppressed and wrinkles on the master are suppressed even when the master is sandwiched by the transport means. It was

However, when the same transporting means as described above is used when transporting a master having a low strength and consisting essentially of a thermoplastic resin film, it is easily undulated if the stretching force of the master is locally different. However, there is a problem that wrinkles occur due to the waving being pinched by the conveying means. In particular, when the master is conveyed while being pressed against the surface of the thermal head by the platen roller, conventionally, both ends of the master were conveyed in a free state in which they protruded outward from the nipping portion between the platen roller and the thermal head. However, when the master consisting essentially of the thermoplastic resin film is conveyed in this way, there is a problem that wrinkles occur at the boundary portion as shown in FIG.

Further, in the conventional stencil printing machine, an extension force is generated between the platen roller and the master roll by applying a load to the master roll so that the platen roller does not bend to the master during conveyance of the master. It is configured. However, when the master roll is attached to the stencil printing machine, if the end face of the master roll is attached in a non-uniform state, the end face of the master pulled out from the master roll will be pulled out in a state protruding from the end face of the master roll. . When the master is conveyed in such a state, the extension force of the master at the part protruding from the end surface of the master roll is different from the extension force of the other part, and the difference in the extension force causes waviness on the master surface. There is a problem that wrinkles sometimes occur.

According to the present invention, even when a thin master having a low strength, such as a master substantially made of a thermoplastic resin film, is used for plate making, the master is conveyed without wrinkling. The purpose of the present invention is to provide a stencil making machine capable of producing a stencil printing machine, and to provide a master substantially consisting of a thermoplastic resin film that suppresses the generation of waviness and wrinkles. An object of the present invention is to provide a plate-making apparatus capable of smoothly carrying a master without overloading the plate-making means when performing.

[0011]

According to the first aspect of the present invention,
A master wound in a roll shape is subjected to heat-melting perforation plate making by pressing and sandwiching it with a thermal head and a platen roller that form a plate making means, and from a roller pair arranged on the downstream side in the master conveying direction of the plate making means. In the plate making apparatus of the stencil printing apparatus for carrying while sandwiching and extending the plate-made master made by the plate making means, the total width of the thermal head and the platen roller is the same as that of the master, or It is characterized by the above.

According to a second aspect of the present invention, a master wound in a roll shape is pressed and sandwiched by a thermal head and a platen roller which constitute plate making means to perform heat melting perforation plate making, and the master conveying of the plate making means is carried out. In the plate making apparatus of the stencil printing apparatus for carrying while sandwiching and extending the plate-made master made by the plate making means, by means of the carrying means composed of the roller pair arranged on the downstream side in the direction, the thermal head and the platen roller The entire width is set to be larger than that of the master, and both side end portions of the thermal head and / or the platen roller, portions that exceed the width of the master are formed to have a lower friction coefficient than a portion that contacts the master. It is characterized by being

According to a third aspect of the present invention, there is provided a roll-shaped master used in a stencil printing apparatus having the plate making apparatus according to the first or second aspect, wherein the width of the master is It is characterized in that it is formed so that it gradually narrows from the beginning of winding toward the end of winding.

[0014]

According to the invention described in claim 1, since the master is sandwiched by the thermal head and the platen roller, the overall width of which is equal to or larger than that of the master, the master is clamped over the entire width. A uniform stretching force is applied over the entire surface.

According to the second aspect of the invention, since the master is clamped over the entire width by the thermal head and the platen roller which are formed over the entire width of the master, the master is uniformly stretched over the entire surface of the master. The force is applied, and both side edges of the thermal head and / or the platen roller, which have widths larger than the width of the master, have a friction coefficient lower than that of the area in contact with the master. Drive load is reduced.

According to the third aspect of the invention, since the width of the master is gradually narrowed from the start of winding toward the end of winding, the stretching force to the master is uniform over the entire surface. Act on.

[0017]

FIG. 1 is a schematic side view of the essential parts of a stencil printing machine adopting an embodiment of the present invention. In the figure, reference numeral 1
Indicates a master roll that is substantially formed of a thermoplastic resin film wound into a roll shape. As shown in FIG. 2, the master roll 1 is formed by winding the master 1a around a support shaft 2, and the master 1a has a width W2 on the winding end side of the support shaft 2 on the winding start side. It is formed to be narrower than W1. In this embodiment, the master 1a has a total length of 100 m, W1 is 270 mm, and W2 is 2 m.
The width of the master 1a is set to 55 mm, and the width of the master 1a is set to gradually change from the winding start to the winding end. The support shaft 2 supports the master roll 1 and is rotatably attached to a side plate (not shown) of the stencil printing apparatus main body. The support shaft 2 is provided with a brake mechanism (not shown) for preventing the master 1a from bending when the master 1a is pulled out from the master roll 1 by a platen roller 4 described later.

On the left side of the master roll 1 (downstream of the master carrying direction), a plate making means 3 mainly composed of a platen roller 4 and a thermal head 5 is arranged. The platen roller 4 is fixed to a support shaft 4a which is rotatably supported by a side plate (not shown), and is rotationally driven counterclockwise by a stepping motor (not shown). The platen roller 4 is formed of an elastic body such as rubber whose overall width is set to be equal to or larger than the overall width of the master 1a. As shown in FIG. 4b that exceeds the width of (only one side is shown in the figure)
Is subjected to surface forced deterioration treatment, etc., and is configured so that the friction coefficient of the surface is reduced as compared with other portions.

The entire width of the thermal head 5 is the master 1
The width is set to be equal to or larger than the entire width of a, and innumerable heating elements are provided on the contact surface with the master 1a, and is biased by a spring member (not shown) in a direction of being pressed against the platen roller 4.
Further, as shown in FIG. 3 (b), a low friction coefficient of tetrafluoroethylene resin or the like is provided on both side end portions of the thermal head 5 which exceed the width of the master 1a (only one is shown in the figure). The member is applied, and the coefficient of friction is reduced as compared with the part in contact with the master 1a.

On the downstream side of the plate making means 3 in the master conveying direction,
A pair of conveying rollers 6 as a conveying unit for conveying the plate-making master 1b made by the plate making unit 3 toward a clamp unit 17 described later is arranged. The transport roller pair 6 is mainly composed of a drive roller 6a and a driven roller 6b, and the total width of each roller is set to be equal to or larger than the total width of the master 1a as shown in FIG.

The drive roller 6a is fixed to a support shaft 6c which is rotatably supported by a side plate (not shown), and is rotated clockwise by a stepping motor (not shown) at a peripheral speed slightly higher than the peripheral speed of the platen roller 4. Is driven to rotate. Further, a torque limiter (not shown) is arranged at the shaft end of the support shaft 6c, and a preset tension acts on the plate-making master 1b between the plate-making means 3 and the transport roller pair 6. .

The driven roller 6b is fixed to a support shaft 6d which is rotatably supported by a side plate (not shown), and is arranged so as to come into pressure contact with the drive roller 6a.
It is driven to rotate in the counterclockwise direction with the rotation of a.

A cutting means 7 is disposed downstream of the pair of transport rollers 6 in the master transport direction. The cutting means 7 comprises a movable blade 7a and a fixed blade 7b, and the movable blade 7a is fixed blade 7a.
The plate-making master 1b is cut by rotating and moving with respect to b. A guide plate 8 fixed to a side plate (not shown) of the stencil printing machine is disposed downstream of the cutting means 7 in the master conveyance direction. The guide plate 8 guides the leading end of the plate-making master 1b toward the clamp means 17 described later.

On the lower left side of the guide plate 8, there is provided a plate cylinder 9 having a porous support cylinder and a mesh screen of resin or metal mesh covering the outer periphery thereof and having an opening 9a. There is. The plate cylinder 9 is a spindle 1 that also serves as an ink pipe.
0 is rotatably supported between the side plates of the stencil printing machine, and is rotationally driven by a plate cylinder driving means (not shown).

Inside the plate cylinder 9, ink supply means 1 for supplying the ink supplied from the spindle 10 to the inner peripheral surface of the plate cylinder 9.
1 is provided. The ink supply means 11 is mainly composed of an ink roller 12 and a doctor roller 13. The ink roller 12 is rotatably supported between side plates (not shown) fixed to the support shaft 10, and the driving force of the plate cylinder driving means is transmitted by a driving force transmission means such as a gear or a belt (not shown). It is driven to rotate counterclockwise in synchronism with 9. The doctor roller 13 is rotatably arranged so that there is a slight gap between the outer peripheral surface of the doctor roller 13 and the outer peripheral surface of the ink roller 12.
The ink in the ink reservoir 14 formed in the wedge-shaped space between and is supplied onto the outer peripheral surface of the ink roller 12.

On the outer peripheral surface of the non-opening portion of the plate cylinder 9, there is provided a clamp means 17 mainly composed of a stage portion 15 and a clamper 16 arranged so as to be able to come into contact with and separate from the stage portion 15. ing. The stage portion 15 is formed of a flat surface including one generatrix of the plate cylinder 9, and its surface is made of a magnetic material. The clamper 16 is rotatably supported by a pivot 16a provided on the stage 15 in parallel with the generatrix of the plate cylinder 9, and a magnet (not shown) is attached to the contact surface with the stage 15. . A pinion gear (not shown) is fixedly installed at one end of the pivot 16a, and an opening / closing means (not shown) for transmitting a rotational force to the pinion gear is provided on the stencil printing machine main body side. With this configuration,
When the plate cylinder 9 is rotationally driven by the plate cylinder driving means and stopped at the plate feeding position shown in FIG. 1, the clamper 16 is opened / closed by the opening / closing means (not shown).

Below the plate cylinder 9, a solid line position in which the outer peripheral surface of the plate cylinder 9 is rockably supported by a rocking means (not shown) and is spaced from the outer peripheral surface of the plate cylinder 9, and the outer peripheral surface is the plate cylinder 9. A press roller 18 is disposed as a pressing means that selectively occupies the position of the two-dot chain line in the figure that contacts the outer peripheral surface of the.

The operation of this embodiment based on the above configuration will be described below. A document to be printed is set on a document reading unit (not shown), and the operator presses a plate making start switch, so that the plate cylinder driving means presses the plate cylinder 9.
Is rotated to a predetermined plate discharge position, and the master of the previous plate wound around the outer peripheral surface of the plate cylinder 9 is peeled off and discarded by a plate discharge device (not shown). After that, the plate cylinder 9 further rotates and stops at the plate feeding position shown in FIG. When the plate cylinder 9 stops at the plate feeding position, a command is sent from a control unit (not shown) to operate the opening / closing unit, the clamper 16 is opened, and the plate feeding standby state is set.

In parallel with the above operation, the document is read by the document reading section. The original image is converted into an electric signal by a CCD or the like, and the heating element of the thermal head 5 is energized in a pulse shape through an A / D converter, a plate making control device and the like. Then, the heating elements of the thermal head 5 selectively generate heat according to the image information, and the platen roller 4 is rotated by the rotation of a stepping motor (not shown) to form a plate-making image on the master 1a pulled out from the master roll 1. To be done. At this time, since the entire width of the pulled-out master 1a is set to be narrower than the entire width of the master 1a not yet drawn out from the master roll 1, the extension force acting on the pulled-out master 1a is spread over the entire surface of the master 1a. It acts uniformly and prevents the waving of the master 1a. Also,
Since the portions 4b and 5a of the platen roller 4 and the thermal head 5 that exceed the width of the respective masters are set to have a low friction coefficient, the stepping motor that drives the platen roller 4 is not overloaded, and The drive is smooth.

When the platen roller 4 starts rotating, the driving roller 6a starts rotating by the rotation of a stepping motor (not shown), and the plate-making master 1b on which the plate-making image is formed by the plate-making means 3 is guided by the guide plate 8. It is conveyed to the clamp means 17. At this time, the platen roller 4, the thermal head 5, and the conveying roller pair 6 have the respective total widths set to be equal to or larger than the total width of the master 1a, so that the master 1a at the time of platemaking is given a uniform stretching force. The corrugation in the means 3 and the generation of wrinkles in the transport roller pair 6 are prevented.

When it is judged from the step number of the stepping motor for driving the platen roller 4 that the plate making is completed by the control means (not shown), the movable blade 7a is rotationally moved to cut the plate making master 1b and the platen roller is cut. 4 and the drive roller 6a are stopped from rotating. After that, the plate-making master 1b that has been cut and remains on the guide plate 8 is pulled out by the rotation of the plate cylinder 9, and the winding operation of the plate-making master 1b on the plate cylinder 9 is completed.

After the winding operation is completed, the plate cylinder 9 is rotated at a low speed by the plate cylinder driving means. At the same time, one sheet of printing paper is fed from a paper feeding device (not shown), and is fed between the plate cylinder 9 and the press roller 18 after being timed by a pair of registration rollers (not shown). When the paper detection means (not shown) detects that the printing paper has been fed between the plate cylinder 9 and the press roller 18, the press roller 18 is moved to the position of the chain double-dashed line in FIG. The paper is pressed against the outer peripheral surface of the plate cylinder 9. When the printing paper is pressed, the ink supplied to the inner peripheral surface of the plate cylinder 9 by the ink supply means 11 exudes from the opening 9a,
After being supplied to the plate-made master 1b, the plate-made master 1
Transfer to the printing paper via the perforated portion of b. After that, the printing paper is peeled from the outer peripheral surface of the plate cylinder 9 by a peeling claw (not shown), and is discharged to the outside of the machine by a paper discharging means (not shown). By this series of operations, the plate making master 1b is brought into close contact with the outer peripheral surface of the plate cylinder 9, and the plate attaching operation for transferring the ink to the printing paper is completed.

After the printing operation is completed and the printing conditions are set by the operator, the printing start switch is pressed to rotate the plate cylinder 9 at a high speed, and the printing paper is continuously fed from a paper feeding device (not shown). It is fed and printed.

In the above-mentioned embodiment, the press roller is used as the pressing means. However, as the pressing means, an impression cylinder having the same diameter as the plate cylinder 9 and driven to rotate in synchronization with the plate cylinder 9 is used. Good. Incidentally, the master substantially consisting of only the thermoplastic resin film used in the above examples, other than the master consisting of only the thermoplastic resin film, the thermoplastic resin film containing a minor component such as an antistatic agent. In addition, one or a plurality of thin film layers such as an overcoat layer are formed on both main surfaces of the thermoplastic resin film, that is, at least one of the front surface and the back surface. Further, in the above-mentioned examples, a master substantially consisting of a thermoplastic resin film was used as the master, but a conventional master having a laminated structure in which a porous support is attached to the thermoplastic resin film may be used. .

[0035]

According to the invention described in claim 1, the master is clamped over the entire width by the thermal head and the platen roller which are formed to have the entire width equal to or larger than that of the master. Since a uniform stretching force is applied to the entire surface, it is possible to prevent wrinkles from being generated on the master by preventing waviness from occurring particularly on the side edges of the master, and it is possible to obtain a good printed image.

According to the second aspect of the invention, the master is clamped over the entire width by the thermal head and the platen roller which are wider than the master, and a uniform stretching force is applied over the entire surface of the master. The driving load of the platen roller is set by lowering the coefficient of friction of the part which is provided and is at the both ends of the thermal head and / or the platen roller and which exceeds the width of the master, than the part which contacts the master. This reduces waviness on the master to prevent wrinkles from occurring on the master, prevents overloading of the platen roller, and allows the master to be conveyed smoothly, resulting in a good printed image. Obtainable.

According to the third aspect of the present invention, the width of the master is gradually narrowed from the beginning of winding toward the end of winding, so that the stretching force to the master is uniform over the entire surface. As a result, the generation of wrinkles on the master is prevented by preventing the ripples on the master, and a good printed image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic side view of a main part of a stencil printing apparatus adopting an embodiment of the present invention.

FIG. 2 is a diagram showing a master roll for explaining an embodiment of the present invention.

3A and 3B are views showing a platen roller and FIG. 3B showing a thermal head for explaining an embodiment of the present invention.

FIG. 4 is a partial perspective view of a plate making unit and a pair of conveyance rollers for explaining an embodiment of the present invention.

FIG. 5 is a view showing a master sandwiched by plate making means for explaining a conventional problem.

[Explanation of symbols]

 1 Master Roll 1a Master 1b Plate Making Master 3 Plate Making Means 4 Platen Roller 5 Thermal Heads 4b, 5a Parts Exceeding Master Width 6 Conveying Means (Conveying Roller Pair) W1 Width of Winding Start Side W2 Width of Winding End Side

Claims (3)

[Claims] 1. A roll-wound master is pressed and sandwiched between a thermal head and a platen roller that constitute plate making means to perform heat melting perforation plate making, and the master is arranged downstream of the plate making means in the master conveying direction. In the plate making apparatus of the stencil printing apparatus that carries while sandwiching and stretching the plate-made master made by the plate making means, the total width of the thermal head and the platen roller is that of the master. A plate making apparatus of a stencil printing machine, which is the same or more. 2. A roll-wound master is pressed and sandwiched by a thermal head and a platen roller that constitute plate making means to perform heat-melting perforation plate making, and the master is arranged downstream of the plate making means in the master conveying direction. In the plate making apparatus of the stencil printing apparatus, which conveys while sandwiching and stretching the plate-made master made by the plate making means, the total width of the thermal head and the platen roller is that of the master. The above is characterized in that both side end portions of the thermal head and / or the platen roller, portions that exceed the width of the master are formed to have a lower friction coefficient than portions that contact the master. Plate making equipment for stencil printer. 3. A roll-shaped master used in a stencil printing machine having the plate-making apparatus according to claim 1, wherein the width of the master is from the winding start side to the winding end side. A master used in a plate making apparatus of a stencil printing apparatus, which is formed so as to become gradually narrower as it goes.