JPS62132640A - Preparation of thermosensitive stencil printing plate - Google Patents

Abstract

PURPOSE:To enable a printing plate to be directly prepared through thermosensitive process in high-quality image based on informatoin converted in electric signal by overlapping an energized thermal recording head on a thermosensitive stencil printing-plate sheet and causing an energized heating element to selectively heat on a recording signal. CONSTITUTION:A thermosensitive stencil printing-plate sheet (hereafter called 'thermosensitive sheet') 11 is held on a support plate 12. This thermosensitive sheet 11 has an energized thermal recording head 10 overlapped. If a recording signal corresponding to an original image is selectively applied to each heaging element 13a-13n through drive circuits 15a-15n while lightly pressing the energized thermal recording head 10 to the thermosensitive sheet 11 to heat the heating elements, the thermoplastic contracting resin of the thermosensitive sheet 11 corresponding to the heated part becomes soft, melting to form a microorifice. Thus it is possible to prepare a stencil printing plate directly form information converted a electric signal without being through a hard copy.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for producing a printing original plate in stencil printing, and more specifically to a method for producing a thermal stencil printing original plate.

[Prior Art] As is well known, stencil printing is a printing method in which microscopic holes are formed in the original pattern on an original sheet, and printing ink is supplied to the printing paper surface through circulation, and is widely used due to its simplicity. has been made into

The printing original plate used in this stencil printing has conventionally been prepared using (a) a method of forming perforations using energy generated by selective discharge of discharge needles; and (b) an original sheet in which a thermoplastic shrinkable resin is integrated with a mesh-like support. It was made using a heat-sensitive stencil plate-making method, in which the image area was overlaid on the original and exposed to short-term light such as a flash to generate heat, causing the resin to heat-shrink and perforate it.

FIG. 7 is a diagram illustrating the latter thermal stencil printing method described in Section 2, in which a thermal stencil printing original sheet 1 is superimposed on a document 2 having an image area 3, and the original sheet 1 is irradiated with a xenon flash lamp 4. do. 2. The heat-sensitive stencil printing original sheet 1 is made by coating a thin film of thermoplastic shrinkable resin on a coarse porous mesh-like sheet such as Japanese paper. As is known from Japanese Patent No. 49-6567, vinyl chloride and vinylidene chloride copolymers, polystyrene, cellulose acetate, etc. are used. The sheet is finished to be several tens of microns thick, and there is a transparent plate (not shown) on the flash lamp side.
The sheet 1 and the original 2 are brought into close contact with each other by pressing the back side of the original with an elastic member (not shown).

The flash lamp 4 emits light for a short period of time on the order of 1/1000 seconds, and irradiates the sheet 1. Then,
The image area 3 of the document 2 absorbs light and is rapidly heated, selectively melting the thermoplastic resin of the heat-sensitive sheet to form perforations before the heat is dissipated to the base paper.

FIG. 8 is a diagram showing a cross section of Sea I after plate making,
This shows a state in which a large number of micropores 5 are formed in the shape of an image as a result of shrinkage around the thermoplastic resin in the area corresponding to the image area of the original or the porous structure that supported it. There is.

[Problem to be solved by the invention] By the way, the conventional thermal stencil printing method described above is extremely convenient when the manuscript is already prepared in the form of a hard copy, but the information to be printed cannot be read by the scanner. In the case of information signals that have been generated by a computer, or that have been stored in memory with an intervening electrical signal, they must first be converted to a notebook copy using a printer and then flash plate-making must be performed. There was the annoyance of not having to do so.

Furthermore, when converting to a hard copy, if the performance of the printer or the quality of the coloring material of the hard copy is poor, good plate making cannot be performed. For example, images printed by an electrophotographic printer such as a laser beam printer, which can produce visually very good images, are
There were minute toner scatterings in the non-image areas that could not be seen with the naked eye, and when printed images were printed using this as a manuscript, there was a drawback in that the non-image areas were left with splatters that looked like sand had been sprinkled on them. .

Therefore, the object of the present invention is to eliminate the above-mentioned drawbacks of the conventional method and to provide a new thermal stencil plate that can directly perform thermal plate making with high image quality without intervening note copying from information converted into electrical signals. The purpose is to provide a method for creating a printing original plate.

[Means and effects for solving the problems] In the present invention, fine pores are created by applying heat in the shape of an original image to a thermal stencil printing original sheet formed by integrating a thermoplastic resin and a mesh-like sheet. In the plate-making method, an energized heating recording head having energized heating elements divided into pixel units is superimposed on a thermal stencil printing original sheet, and the energized heating elements are selected by a recording signal corresponding to the original image applied to the head. This heat generation causes micropores to be formed in the thermal stencil printing original sheet.

[Example] The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows a first embodiment of the method for producing a thermal stencil printing original plate according to the present invention, in which a thermal stencil printing original sheet (hereinafter referred to as a thermal sheet) 11 is connected to a support plate 12.
held on top. Then, -5=The energized heat-generating recording head 14 is superimposed on this heat-sensitive sheet 11. This recording head once has the same structure as what is normally called a thermal printer head. That is, in this embodiment, a heating resistor is divided into pixel units and applied on a heat-resistant insulating substrate 16 such as ceramic or glass to form energizing heating elements 13a to 13n, and a wear-resistant layer is applied thereon. Protective layer 14 for improving
Each heating element 138 to 13n
are connected to energization drive circuits 15a to 15n, respectively.

Note that various configurations known and used for thermal printers can be applied to the energized heat generating recording head 10.

With this configuration, the energizing heat-generating recording head 10 is pressed lightly against the heat-sensitive sheet 11, and recording signals corresponding to the original image etc. are transmitted through the drive circuits 15a to 15n.
When the heat is selectively applied to the registered heating elements 138 to 13n to generate heat, the thermoplastic shrinkable resin of the heat-sensitive sheet corresponding to the heat-generating portions is softened and melted to form fine openings. Therefore, a stencil printing original plate can be made directly from information in the form of electrical signals without intervening a hard copy.

In addition, thermal sheets are usually thin sheets of several tens of microns and easily wrinkle or fold, making them difficult to handle alone, so they are supported with a cardboard frame or held on the back of another supporting paper. However, in the conventional thermal stencil-making method, as shown in Figure 7, the original and the thermal sheet are overlapped and flash light is applied from the thermal sheet side, so at least in the plate-making process, the thermal sheet is It is necessary to face the document either alone or supported by a transparent support, and this has been the case in the past.

However, in the method according to the present invention, the energized heat-generating recording head can be brought into contact with the heat-sensitive sheet and the recording head and the heat-generating sheet can be moved relative to each other, and the heat-sensitive sheet can be held on another support part H during plate making. The situation is such that there is no harm in doing so.

FIG. 2 shows a second embodiment of the production method according to the present invention. In this embodiment, perforation is recorded line by line while moving the recording head during plate making, and one screen is recorded by moving the heat-sensitive sheet. The original plate making device is configured as a serial printer type that forms the original plate. That is, in FIG. 2, a heat-sensitive sheet 19 is wound around a large-diameter sheet feeding roller 17 that rotates in the direction of the arrow, is pressed by a pressure roller 18, and is fed onto the recording section support plate 20. There is. A heat generating element array 22 of an energized heat generating recording head 21 is opposed to the recording unit support plate 20 . In addition,
A guide plate 23 is provided near the outer periphery of the sheet feed roller 17 and is curved toward the pressure roller 18 .

As described above, in the master plate making apparatus, during plate making, the heat sensitive sheet 19 is manually fed prior to plate making, guided by the guide plate 23, and fed until its leading edge is positioned on the recording section support plate 20. During this time,
The pressure roller 18 is spaced apart, and is brought into pressure contact after feeding the heat-sensitive sheet 19. Next, the recording section support plate 20
The recording head 21 is moved in a direction perpendicular to the paper surface of the drawing while being lightly pressed against the heat-sensitive sheet 19 held as a support surface to perform plate making for one line.

By the way, in the original plate making apparatus configured as described above, there is a problem that when the heat-sensitive sheet 19 is attached, the heat-sensitive sheet 19 is too weak to feed the leading edge of the sheet to the position of the support plate 20. Furthermore, if the heat-sensitive sheet 19 is fed alone during plate making, its mechanical strength is extremely weak, so the recording head 21
There is a problem with the head being dragged when moving, causing wrinkles and tears.

Therefore, in order to eliminate such problems, in the plate making method of this embodiment, a thermosensitive sheet supported by a support paper is used during plate making.

FIG. 3 shows an example of the structure, in which a heat-sensitive stencil printing original sheet 24 is adhered to a support paper 25 over the entire surface with a weak adhesive force. After plate making is completed, both are peeled off during printing and only the heat-sensitive sheet 24 is used as a printing original plate. Since the heat-sensitive sheet 24 is supported by the support paper 25, it is easy to handle during normal handling, and when fed into the apparatus, it can be fed well according to the properties of the support paper. Further, even if the sliding force of the recording head is applied during plate making, the heat-sensitive sheet is stably supported by the support paper during plate making, so wrinkles and folds do not occur. The support paper 25 usually has a paper weight of 50 to 150
g/rr? It is preferable that the heat-sensitive sheet 24 is affixed to the entire surface with a weak adhesive such as polyvinyl alcohol.

In addition, in the original plate production method of the present invention, a combination of the thermoplastic resin abrasive applied to the heat-sensitive sheet, the abrasive quality of the surface protective layer of the recording head, the smoothness of the recording head surface, the heat generation temperature of the energized heating element, etc. In some cases, the heat-sensitive sheet I. may stick to the surface of the energized heat-generating recording head, or a portion of the thermoplastic resin may adhere to the head surface, resulting in poor plate making. However, such a risk can be avoided by providing a thin film layer that can be removed after plate making between the heat-generating recording head and the heat-sensitive sheet.

In addition, by selecting a material with good lubricity for such a thin film layer, the recording head runs smoothly and prevents the generation of frictional forces and adhesive forces that act on the heat-sensitive sheet and cause wrinkles and folds. can.

It is preferable that this thin film layer be thin in order to prevent heat diffusion, and of course it needs to be made of a material with excellent heat resistance and good slipperiness. Most suitable are polyester sheets and condenser paper sheets, which are used as base materials for ink sheets, and have a thickness of several microns to several tens of microns.

FIG. 4 shows a third embodiment of the present invention in which a thin film layer is interposed between the heat-sensitive sheet and the recording head. The thermosensitive sheet 24 is held, and a thin film layer 26 is interposed between the sheet 24 and the recording head 10.

With this configuration, the recording head 10 is
moves by sliding on the surface of the thin film layer 26, and at the same time performs plate making while scanning the heat-sensitive sheet 24 with relative movement. The thin film layer has excellent heat resistance and good activity, so there is no possibility of hot melting substances adhering to the head surface, and strong adhesion and frictional forces work between the head and the thin film layer, extending the life of the head. It also prevents the application of forces that would reduce the heat-sensitive sheet or cause wrinkles or folds in the heat-sensitive sheet or thin film layer.

In this embodiment, a thin film layer is interposed between the heat-sensitive sheet and the recording head at least during the plate-making process using heat-sensitive recording. Various methods can be used to remove it.

Next, one method that is easy to carry out is shown in FIG. 5. A heat-sensitive sheet 24 and a thin film layer 26 are prepared in advance in a bonded state, and the thin film layer 26 is peeled off after the thermal plate making process is completed. The configuration of a plate-making apparatus using a sheet formed in this manner does not require a mechanism for introducing or removing a thin film layer, and is extremely simple.

Although an example is shown in which the heat-sensitive sheet 24 is supported by the support paper 25, this is not an essential element and can be omitted if it does not hinder the feeding of the heat-sensitive sheet and does not cause wrinkles or folds. Good too.

In addition, in the method shown in Fig. 5, in the thermal plate-making process, the thermal convex plastic resin is melted and micropores are formed at the same time.
As a result of a part of it adhering and solidifying to the thin film layer, the thin film layer and the heat-sensitive sheet become even more strongly bonded. On the other hand, in the method shown in FIG. 5, the thin film layer can be arbitrarily separated manually after plate making, so there is no need for such consideration, which is advantageous.

FIG. 6 shows a fourth embodiment of the present invention, in which the thin film layer is formed of a tape housed in a cassette, and is sequentially supplied and wound as the plate-making process progresses. It becomes.

That is, the cassette 27 is placed opposite the thermosensitive sheet 24 supported by the support paper 25. A tape 35 forming a thin film layer is housed within the cassette case 28. This tape 35 is wound into a roll around a rotatable supply shaft 29, and the tape 35 pulled out from the supply roll is pulled out by guide pins 31 and 32 on the front side of a notch 33 provided at the center of the front of the case. After being stretched, it is wound up into a roll around a rotatable winding shaft 30. A recording head 34 is fitted into the notch 33, and the cassette 27 is detachably attached to the head 34.

While the cassette 27 and the recording head 34 constructed in this way are moved together in the direction of the arrow a, the tape 35 is wound up in the direction of the arrow. At this time, if the moving speed of the cassette 27 in the direction a is equal to the moving speed of the tape 35 within the cassette 27, the thermal plate making is performed in a state where the thin film tape 35 and the heat-sensitive sheet 24 do not move relative to each other.

Furthermore, in the above-described operation, it is not always necessary to move the tape 35 relative to the cassette at a speed equal to the moving speed of the cassette.

In order to prevent unnecessary consumption of tape, it is extremely effective to move the tape in the image area but stop it in areas where there is no image.

It is also possible to reduce tape wear by making the tape moving speed slower than the cassette moving speed.

In the embodiment shown in FIG. 6, it is necessary that the thin film layer tape 35 and the heat-sensitive sheet 24 can be easily separated after the plate-making process. To achieve this, the tape is made of a material with good release properties, the surface is coated with a coating that increases release properties, and the peeling force required to peel the tape from the heat-sensitive sheet in the right angle direction as the cassette moves is reduced. Therefore, consideration must be given, such as devising the structure of the cassette.

[Effects of the Invention] As described above, according to the present invention, it is possible to directly generate a thermal stencil printing original plate based on image information that has been converted into an electrical signal without deteriorating the image quality. Therefore, plate making can be performed directly from image information in the form of electrical signals without intervening a hard copy. A remarkable effect is exhibited in that it can be removed and good plate making can be performed.

Moreover, the energized heat-generating recording head can be applied with a thermal printer head that has been improved to transmit the generated heat efficiently and evenly and without much diffusion. It is possible to perform higher-definition plate making than flash plate making. Furthermore, once an image is printed out on a hard copy, there are various variations in image forming colorants, etc., and it is not necessarily suitable for thermal stencil making, and good plate making is not always possible. In the method of the present invention, there is no restriction in this sense, and therefore,
This is extremely convenient for making plates from information in the form of electrical signals.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an original plate making apparatus showing a first embodiment of the making method of the present invention. FIG. 2 is a sectional view of essential parts of an original plate making apparatus showing a second embodiment of the making method of the present invention. FIG. 3 is an enlarged sectional view of essential parts showing a heat-sensitive sheet and a support paper. FIG. FIG. 6 is a perspective view of essential parts showing a heat-sensitive sheet; FIG. 6 is a front view of an original plate making apparatus showing a fourth embodiment of the making method of the present invention; FIG. 7 is a schematic cross-section of the original plate making apparatus showing a conventional original making method. FIG. 8 is an enlarged sectional view of the main part of the thermal stencil printing original plate. 5・・・・・・・・・・・・・・・・・・・・・・・・
Fine holes 10, 21, 34... energized heat generating recording head 11
．． 19.24...Thermal stencil printing original sheet 13a~
13n... Current heating element plane 8 [

Claims (1)

[Scope of Claims] A plate-making method in which micropores are formed by applying heat in the shape of a document image to a heat-sensitive stencil printing original sheet formed by integrating a thermoplastic shrinkable resin and a mesh-like sheet, comprising: An energized heat generating recording head having energized heat generating elements divided into pixel units is superimposed on a thermal stencil printing original sheet, and the energized heat generating elements are selectively caused to generate heat by recording signals such as original images applied to the head, and the heat generating elements are selectively caused to generate heat. 1. A method for producing a thermal stencil printing original plate, characterized in that fine holes are formed in a thermal stencil printing original sheet by: