JPH0725177A - Original plate for printing stencil - Google Patents

Abstract

PURPOSE:To provide an original plate for printing a stencil in which an excellent printing plate can be formed by a thermal head even if ink of high viscosity is sealed and sealing can be conducted immediately after it is perforated. CONSTITUTION:An original plate for printing a stencil is formed by sequentially laminating a heat sensitive stencil base sheet 12, ink disposed at a porous support side of the sheet 12 and a film 20 of an ink impermeable base material, wherein viscosity at an ink shearing speed of 300sec<-1> is 10,000cPs or more (at 25 deg.C) and ink is immersed to a foamed material 16 having continuous foam which has a foam size of 0.2mm or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing plate.

[0002]

2. Description of the Related Art Conventionally, a heat-sensitive stencil sheet that can be perforated by infrared irradiation or a thermal head has been known. A typical example thereof is one in which a thermoplastic film and porous thin paper are laminated with an adhesive. As a stencil printing apparatus using such a heat-sensitive stencil sheet, a pressing stencil printing apparatus as shown in FIG. 5 is known. This is a heat-sensitive stencil sheet 70 obtained by adhering a thermoplastic film and a porous support to each other. A heat-sensitive stencil original plate 76 having a concave portion 84 as a coating portion is used.

This printing apparatus includes a pressing member 78, a pedestal 80 arranged to face the pressing member 78, and a pressing member 7.
8 and a holding member 82 of the heat-sensitive stencil original plate 76 arranged in the peripheral portion of the surface facing the pedestal 80. Recessed portion 8 formed by frame body 72 of perforated heat-sensitive stencil original plate 76
4 is a device that prints by applying ink to the sheet 4, covering the cover sheet 74 with the holding member 82 by the holding member 82, and moving the pressing member 78 to the pedestal 80 via the printing paper 86.

In this printing apparatus, when a high viscosity ink having a viscosity of 20,000 cPs or more (25 ° C.) at a shear rate of 30 sec ⁻¹ is used, very good printing quality can be obtained.

However, in the press type stencil printing machine, the user has to apply ink, so that the hands and clothes are soiled when applying the ink, and the ink thickness is not uniform, resulting in uneven printing. There was a drawback.

In order to improve the above drawbacks, a stencil printing plate 50 as shown in FIG. 6 can be considered. The stencil printing plate 50 includes a heat-sensitive stencil sheet 12 in which a thermoplastic film 11 and a porous support 13 are bonded together, a frame body 18,
A film 20, which is an ink impermeable base material, is sequentially laminated. The space formed by the frame body 18 is filled with the ink 57 in advance, and the ink 57 is kept in a sealed state.

In the stencil printing plate 50, a perforated image is formed by heating and melting the surface of the thermoplastic film 11 of the heat-sensitive stencil sheet 12 by a plate making apparatus using a thermal head. Hereinafter, the formation of the punched image is referred to as plate making.

Next, the stencil printing plate 50 thus prepared is
Printing is performed by being attached to a pressing member having a grip (hereinafter referred to as a stamp member) and pressing the stamp member against the printing paper.

[0009]

However, there are problems in making the stencil printing plate as described above. That is, the thermal head is strongly pressed against the stencil sheet when making the stencil sheet. However, at this time, since only the ink is present on the back surface of the heat-sensitive stencil sheet, the stencil sheet may escape due to the pressure of the thermal head, and good perforation may not be performed.

Furthermore, since the pressure of the thermal head increases the pressure of the ink in the stencil printing plate,
Ink oozes out from the perforated portion and adheres to the thermal head, or unnecessary ink adheres to the thermoplastic film surface (hereinafter referred to as the stamp surface) of the stencil printing plate other than the perforated portion. There are also problems.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a stencil printing original plate which can perform plate making satisfactorily and can immediately perform a marking operation after perforation. And

[0012]

Therefore, in the stencil plate of the present invention, a heat-sensitive stencil sheet obtained by adhering a thermoplastic film and a porous support, and the heat-sensitive stencil sheet on the side of the porous support. Is a stencil printing plate which is formed by sequentially laminating an ink arranged in an ink-impermeable substrate and an ink-impermeable substrate, wherein the viscosity at a shear rate of 30 sec ^-1 of the ink is 10,000 c
Ps or more (25 ° C) and the ink has a bubble diameter of 0.
It is characterized by being impregnated into a foam having open cells of 2 mm or more.

[0013]

According to the stencil printing plate of the present invention having the above-mentioned structure, since the stencil sheet is supported by the foam, even when pressure is applied to the stencil sheet by the thermal head during plate making, The stencil sheet is punched without escaping. In addition, similarly, ink does not easily leak from the perforated portion during perforation.

By mounting the stencil printing plate on the stamp member and pressing the stamp member against the printing paper, the ink oozes out from the perforated portion of the heat-sensitive stencil paper to perform stencil printing.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The same members as the conventional members are designated by the same reference numerals, and detailed description thereof will be omitted.

The construction will be described with reference to FIG. 1 which is a cross-sectional view and FIG. 2 which is an exploded perspective view of a stencil printing plate according to the present invention. The stencil printing plate 10 is roughly divided into a heat-sensitive stencil sheet 12 composed of a thermoplastic film 11 and a porous support 13, an ink-impregnated foam 16, and a foam 16 surrounding the foam 16. It is composed of a frame 18 and a film 20 which is an ink impermeable base material.

As the material of the thermoplastic film used for the heat-sensitive stencil sheet 12, the thermoplastic film 22 in this embodiment is a polyethylene terephthalate film (hereinafter referred to as PET film) having a thickness of 2 μm. . Other examples include films of polypropylene, vinylidene chloride-vinyl chloride copolymer and the like.

When a PET film is used, its thickness is preferably 1 μm to 4 μm. A PET film having a thickness of less than 1 μm is not practical because it has a high manufacturing cost and weak strength. On the other hand, since a general thermal head can apply only energy of about 50 mJ / mm ^2, it is not possible to perforate even if a thermal head of 4 μm or more is used.

The porous support 13 is mainly made of, for example, natural fibers such as Manila hemp, Kozo and Mitsumata, synthetic fibers such as polyethylene terephthalate, polyvinyl alcohol and polyacrylonitrile, and semi-synthetic fibers such as rayon. A thin paper is used.

As shown in FIG. 1, the heat-sensitive stencil sheet 12 having the above structure is bonded to the frame body 18 at four sides by the adhesive layer 15.

The foam body 1 is provided at the center of the frame body 18.
An opening corresponding to the size of 6 is provided.

The stencil printing plate 10 described above is made by a plate making apparatus (not shown). As a plate-making device, the surface of the thermoplastic film 11 of the heat-sensitive stencil sheet 12 is selectively heated by a thermal head so that mirror image printing is performed according to print information, and a predetermined portion of the thermoplastic film 11 is heated and melted. A device for piercing is used. During plate making,
The thermal head is a stencil printing master plate 1 with a predetermined pressing force.
It is contacted with 0. At this time, since the ink-impregnated foam 16 is on the back surface of the heat-sensitive stencil sheet 12, the heat-sensitive stencil sheet 12 does not escape even when pressed by the thermal head. Therefore, the stencil sheet 1
In 2, good perforations are formed.

As the foam 16, a foam having a cell diameter of 0.2 mm or more, preferably 0.4 mm or more and having continuous cells is preferably used. Examples of the material of the foam include polyurethane, NBR (acrylonitrile butadiene rubber), and polyethylene.

This foam is impregnated with an ink having a viscosity of 10,000 cPs or more, preferably 20,000 to 50,000 cPs at a shear rate of 30 sec ^-1 measured by a cone-plate type viscometer at a temperature of 25 ° C.

Usually, when an ink pad for a stamp is manufactured, the foam is immersed in the ink so that a large amount of ink can be impregnated in the foam in a short time.
Vacuum impregnation is carried out under vacuum. However, in order to impregnate an ink having a viscosity of 10,000 cPs or more by vacuum impregnation, it is necessary to soak for a very long time. Moreover, it is difficult to impregnate a sufficient amount of ink even if it takes a long time.

However, in this embodiment, the bubble diameter is 0.2 mm.
Since the above coarse foam 16 is used, it is possible to easily impregnate a high-viscosity ink of 10,000 cPs or more without performing vacuum impregnation. That is, as shown in FIG. 3, a nozzle 26 of a cylinder to which ink is supplied is brought into close contact with the foam body 16, and ink is ejected from the nozzle 26 while moving on the foam body 16 by a moving means (not shown).
Move in the direction of the arrow in the figure. By setting the amount of ink discharged from the nozzle 26 to an appropriate value with respect to the moving speed of the nozzle 26, a desired amount of ink can be supplied to the foam 16.
Can be impregnated.

Here, when a foam having a bubble diameter of 0.2 mm or less is used, not only impregnation becomes difficult but also the movement of ink in the foam 16 is difficult. In particular,
This becomes particularly noticeable when the ink has a high viscosity of 10,000 cPs or more. Therefore, when the ink is used in a part of the plate and the ink in that part becomes scarce, the movement of the ink in the foam 16 does not occur even if the ink in the other part is still sufficient. Due to the difficulty, no ink is replenished to the ink deficient portion.

As a result, as a whole of the foam body 16,
Even if a large amount of ink is still impregnated, the printed matter may be faint in the ink-deficient portion.

On the contrary, when a very coarse foam having a bubble diameter of 3 mm or more is used, the ink can easily move in the foam, but the surface state of the heat-sensitive stencil sheet 12 of the stencil printing plate 10 is As a result, the unevenness becomes severe reflecting the surface condition of the foam. Therefore, even if the head is pressed against the heat-sensitive stencil sheet, the heat-sensitive stencil sheet and the head cannot be sufficiently brought into close contact with each other, so that the heat-sensitive stencil sheet cannot be uniformly made.

The stencil printing plate 10 thus prepared is mounted on a stamp member 34, as shown in FIG. The stamp member 34 includes a handle portion 36, a cushion layer 38, and an adhesive layer 40. Master plate 10 for stencil printing
Is attached by adhering the film 20 side of the stencil printing plate 10 to the adhesive layer 40 of the stamp member 34.

In this state, the stamp member 34 is attached to the printing paper 4
When pressed against 2, the foam 16 is compressed and the impregnated ink oozes out from the perforated portion of the printing surface to transfer the ink to the printing paper 42.

It should be noted that the present invention is not limited to such embodiments, and can be carried out in various modes without departing from the scope of the present invention.

[0034]

As is apparent from the above description, in the stencil printing plate of the present invention, since the high viscosity ink is impregnated in the foam to be enclosed in the stencil printing plate, it is used. When performing plate making with a thermal head or the like, the stencil sheet does not escape due to the pressing force of the thermal head, and good perforation can be performed. Further, after plate making, printing can be started immediately by attaching to a holder or the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a stencil printing plate according to the present invention.

FIG. 2 is an exploded perspective view of a stencil printing plate.

FIG. 3 is a diagram showing a method of filling ink in a foam.

FIG. 4 is a diagram showing a usage pattern of an original plate for stencil printing.

FIG. 5 is a cross-sectional view of a conventional pressing stencil printer.

FIG. 6 is a cross-sectional view of a conventional stencil printing plate.

[Explanation of symbols]

 10 Master plate for stencil printing 11 Thermoplastic film 12 Thermosensitive stencil base paper 13 Porous support 15 Adhesive layer 16 Foam

Claims (1)

[Claims] 1. A heat-sensitive stencil sheet obtained by adhering a thermoplastic film and a porous support, an ink arranged on the porous support side of the heat-sensitive stencil sheet, and an ink impermeable substrate. In the master plate for stencil printing that is sequentially laminated, the viscosity at a shear rate of 30 sec ^-1 of the ink is 10,00
0 cPs or more (25 ° C), and the ink has a bubble diameter of
An original plate for stencil printing, which is obtained by impregnating a foam having open cells of 0.2 mm or more.