JPS62156952A - Formation of original plate for thermal screen plate printing - Google Patents

Abstract

PURPOSE:To obtain a forming method for original plates having high freedom in forming plates from three-dimensional or thick manuscripts by using a system in which an original image is optically read by a photoelectric conversion element and converted into electric signals, and on the basis of the signals, a thermal writing head is controllably driven to form fine holes corresponding to the original image in a plate. CONSTITUTION:In a reading process A, an original 1 is organically combined with a photoelectrical conversion element, e.g., optical reading head 2 consisting of CCD image sensor array of double or contracted image projection type, by a mechanical optic system 3 and scanned to optically read out the original image. The image is converted into an electric signal after being amplified and rectified by a reading circuit 4 and sent to the signal processing circuit 5 of a signal processing process B for matching signal forms. The signal so processed is sent to a plate making process C, where signal is applied to the electric heating resistors 32a-32n of a thermal wiring head 7 by a writing drive circuit 6. In this case, a thermoplastic resin is melted by application of heat of the heating elements selectively driven to a thermal holed printing plate 9 to form fine holes 36. Plates can thus be effectively made from three- dimensional or thick originals.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for producing a thermal stencil printing original plate in which fine pores are formed by selectively applying heat to a thermal stencil printing original sheet in an imagewise manner. .

[Conventional technology]

The stencil printing method is a printing method in which microscopic holes are formed in an original sheet in correspondence with original image information, and printing ink is supplied to the printing paper surface through the microscopic holes, and is widely put into practical use due to its simplicity.

Conventionally, as a method for creating a stencil printing original plate used in the above-mentioned printing method, a stencil printing original plate is created in which a plate material is placed under a discharge needle and perforations are formed corresponding to the original image by selectively straightening the discharge needle. In this method, a plate material made of thermoplastic shrinkable resin and a mesh-like sheet such as Japanese paper is superimposed on the original, and the image part of the original is instantly exposed by flash exposure from the plate side. It is produced by a method of producing a thermal stencil printing original plate, etc., in which the resin is heated to soften and shrink, thereby forming perforations.

FIG. 7(a) shows the method for producing the thermal stencil printing original plate described above.

This will be explained using (b). In the figure, 101 is a thermal stencil printing original plate sheet, 102 is a manuscript, 103 is a drawing part of the manuscript,
104 indicates a xenon flash lamp.

The heat-sensitive stencil printing original sheet 101 has a structure in which a thin pattern of thermoplastic or shrinkable resin is coated on a coarse porous, mesh-like sheet such as Japanese paper. Examples of resins that can be used include vinyl chloride, vinylidene chloride copolymer, polystyrene, cellulose acetate, etc., as disclosed in Japanese Patent Publication No. 49-6567. This original sheet 1
01 is finished with a thickness of several tens of microns, and is notated by facing the flash lamp 104 through a transparent plate (not shown), and with the manuscript 102 superimposed below the original sheet 101. The original 102 is pressed onto the original sheet 101 by applying pressure from the back side of the original 102 with an elastic member.
is crimped. Flash lamp 104 is I/10
r) It emits a 0-second flash of light, and the image area 103 absorbs this light and generates heat, which rises to a high temperature before being dissipated by heat conduction, and this heat causes the area corresponding to the image area 103 to As the thermoplastic resin film softens, melts, and contracts, the perforations 1) and 105 are formed. That is, FIG. 7(b)
As shown in FIG. 2, when the thermoplastic shrinkable resin corresponding to the image display area 103 of the original 102 melts, it contracts around the porous structure that supports it, and a large number of fine particles are formed in the image shape. A hole is formed.

This manuscript plate making method has the advantage that plate making can be made extremely easily and in a short time, and the configuration of the apparatus can be simplified.

[Problem that the invention seeks to solve]

In the conventional technology, good plate-making effects can be obtained for black images because they absorb heat relatively easily, but in the case of color images, the plate-making effects deteriorate significantly because the heat absorption efficiency differs depending on the color. As a result, the color sensitivity of plate making deteriorates.

Furthermore, in the case of black-and-white manuscripts, such as images copied by a dry copying machine or manuscripts written in pencil, invisible toner scatters and pencil fine powder scatters in non-image areas, and these fine powders become part of the background during plate-making. A large number of perforations may be formed in the non-image area, resulting in a stain that looks like sand. Moreover, even black and white images can be printed
In the case of dry-copied images, etc. of R copier, the light absorption property is too good and excessively thick perforations are formed, leading to deterioration of image quality. In addition, water-based pens that use black dye as a colorant have problems such as poor light absorption, as well as the ink density gradually becoming thinner as the ink is consumed, making the density of the original image unstable and resulting in a blurred plate. .

Furthermore, thick originals such as books and three-dimensional objects cannot be made into plates because they cannot be made into close contact with the printing plate sheet. A new document is created by copying with a machine, and the same problem as described above arises in that many perforations are formed in the background non-image area due to toner scattering.

This invention was made with attention to these problems, and it is possible to obtain a plate-making effect similar to the sense of visual perception without being affected by the manuscript production process or differences in heat absorption characteristics of colors, and to improve color sensitivity. An object of the present invention is to provide a method for producing a thermal stencil printing original plate which is excellent in quality and has a high degree of freedom such as making plate making possible from three-dimensional originals or thick originals.

[Means and operations for solving the problems] The present invention optically reads an original image using a photoelectric conversion element and converts it into an electrical signal, and based on this signal drives and controls a thermal writing head to produce a thermal stencil printing plate. The material is made to correspond to the original image and heat is applied to form fine perforations. According to this method, the color sensitivity characteristics can be obtained from the spectral sensitivity characteristics of the photoelectric reading element, which are extremely close to those observed by the naked eye. The plate-making effect is replaced by a reading characteristic similar to that of visual inspection by a photoelectric conversion element, which prevents the formation of unexpected caps in non-image areas and poor printing quality, and non-contact reading by an optical reading element enables the reading of three-dimensional originals and It is possible to make plates without any problems even from thick books and manuscripts made from highly uneven paper.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a flowchart showing the steps of the plate-making process of this invention.
First, in reading step A, an original 1 and an optical reading head 2 consisting of a photoelectric conversion element, such as a 00D image sensor array of the same magnification or reduced image projection type, are organically coupled by a mechanical optical system 3 to perform scanning and scan the original image. read optically,
The output of the head 2 is amplified and shaped by a reading circuit 4 and converted into an electrical signal. The output of this reading circuit 4 is sent to the signal processing circuit 5 of signal processing step B, and in this step B, the signal forms of the previous and subsequent steps are matched, and image or signal processing is performed to obtain a good plate-making effect. image, delete the image, edit Addendum 1, etc. In addition, when targeting a three-dimensional original, etc., if there is an area in the peripheral area of the plate-making screen where there is nothing to reflect the illumination light, or an area where the illumination is weak because it is located away from the reference plane, this area The signal processing step B can remove the information in the form of electrical signals and edit only the necessary portions.

Next, the signal processed in the signal processing step B is sent to the plate making step C, and the write drive circuit 6 applies the signal to the energized heating resistor of the thermal write head 70. At this time, the heat-sensitive stencil printing plate material 9 is held and transferred in association with the thermal writing head 7 by the mechanical system 8, so that the heat of the selectively driven heating element acts on the heat-sensitive stencil printing plate material 9. The thermoplastic resin is melted to form microperforations.

Although a multi-element type sensor such as the RAD 2-piece OOD image sensor was used for the optical reading described above, a configuration such as a drum skinner using a single reading element can also be applied instead. It is high-definition and consists mainly of one circuit with spots.

Furthermore, there is a structure in which seven thermal writing heads are mounted on a heat-resistant insulating ceramic or glass substrate, consisting of an energizing heating resistor divided into pixel units and a wiring section connected to it, and the surface is covered with a protective layer. Applicable. As such a thermal writing head 7, those widely used in thermal recording such as thermal color recording, thermal melt transfer recording, thermal sublimation transfer recording, etc. can be conveniently applied. In addition, there are two types of thermal writing heads: serial printer type that prints in the width of one line, and line printer type that covers the entire recording paper, and the reading head 2 covers the entire document. In such cases, it is appropriate to use a line printer type printer. Note that the line printer type writing head 7
When using the device, scanning in the element arrangement direction is performed electronically, so the main functions are scanning the three mechanical optical systems and moving the thermal stencil printing plate material 9.

Next, an example of a plate-making apparatus to which the printing original plate production method of the present application is applied will be explained with reference to FIG. In Fig. 2, ■ is a document scanning optical reading unit corresponding to reading process A, and ■ is a signal processing process B.
2 is a signal processing unit corresponding to plate-making process 0, and 2 is a plate-making scanning thermal writing unit corresponding to plate-making process 0.

The original scanning optical reading section ■ is placed on the original platen glass 11. Scanning reading optical system assembly 12. The assembly 12 consists of a reading circuit 4, and is integrated in a box body 13 with a lighting rung 14a,
14b, mirror 15. Original image projection 16, C
It is constructed by incorporating an OD IJ near image sensor array 17 and the like. 1 manuscript to be made into plates 1 manuscript table glass
1, and the lighting plates 14a, 14b
is illuminated by the mirror 15. Lens “16”
etc. onto the COD linear image sensor array 17. This αTD +) near image sensor
The array 17 has enough reading elements arranged in a direction perpendicular to the drawing surface to cover the width of the surface of the document to be scanned, and scanning in this direction is performed by electronic scanning by the reading circuit 4.

Scanning in a direction perpendicular to this direction is performed by moving either the document table glass 11 or the scanning reading optical system assembly 12.

The optical information of the original 1 is converted into an electrical signal in the original scanning optical reading section (2), and the signal is sent to the signal processing circuit 5 of the signal processing section H, where it is subjected to necessary processing, and then the plate-making scanning thermal writing section ■It is sent to. This signal processing circuit 5 is basically not essential for configuring the present application, but in practice, it is used to adjust the receiving and passing of electrical signals between the optical reading section (■) and the thermal writing section (■). It is necessary to perform image processing to obtain better prepress images.

On the other hand, the plate making scanning thermal writing section (2) includes a writing drive circuit 6, a thermal writing head 18, a pressure roller 20, a plate material support table 21, 22, a plate material feeding roller 23-
26, Guide Play) 27.28. A known thermal line printer head can be used as the thermal writing head 18, and those having an element density of about 10 to 16 pixels/unit are easily commercially available. The heating elements are arranged in a direction perpendicular to the drawing plane to a length that can cover the entire plate making area, and each heating element is electronically scanned by the write drive circuit 6. Therefore, the printing plate material is scanned over the entire printing area by a feeding mechanism consisting of rollers 20.23''!6, guide plates 27.28, etc.

Next, the operation mode of the thermal writing head 18 is shown in FIG. 3(a).
This will be explained according to (b). The thermal writing head 18 used here includes a heat-resistant insulating support substrate 31 and a current-carrying heating resistor 32 segmented into pixel units, as shown in FIG.
A-32n and a surface protection layer 33, the plate material 34 conveyed by the above-mentioned feeding mechanism is pressed against the heating element portion 19 of the writing head 18 by the pressure roller 20.

In this way, with the printing plate 34 in pressure contact with the writing head 18, the drive circuits 35, r-', and 35n selectively apply the recording signal
When is applied, the heat of the current-carrying heating resistor generated by the signal applied acts on the plate material 34, melting the thermoplastic resin and forming minute perforations 36 as shown in FIG. 3(h). .

Therefore, with such a configuration, the effects described below can be obtained by controlling the heat generation of the thermal writing head 18 based on the signal obtained by optically reading the original image.

(a) An arbitrary pattern of perforations can be formed on the plate material 34.

(The color sensitivity of the bl system is determined by the photoelectric conversion element used to read the original, and can be made to be extremely similar to that seen by the naked eye.

(C) Since the information on the plate-making manuscript can be converted into an electrical signal with conversion characteristics close to that of visual observation, it is not affected by unexpected plate-making effects due to the properties of the coloring agent used to make the manuscript or the dispersion of its fine powder.

(d) Plate making The original is optically projected and read without contact, making it possible to make a plate from a three-dimensional object or a thick original, and to make a plate with variable magnification.

(e) - By performing electrical signal processing on the signal read by the photoelectric conversion element before applying it to the thermal writing head, it is possible to process the plate-making original information to improve the plate-making image quality, edit, etc.

The method for producing a printing original plate of the present application has been described above, including an example of a plate-making apparatus, but it is advantageous to improve the heat-sensitive stencil printing plate material in accordance with the method of the present application.

In the conventional plate-making method, a heat-sensitive stencil printing plate material is superimposed on a document and flash light is irradiated from the plate side, and the plate material is handled as a single sheet at least during the plate-making process.

The plate material used here is made by integrating a thermoplastic shrinkable resin with a sheet of Japanese paper or the like, and is extremely thin, with a thickness of 10 to several tens of microns, and is weak. For this reason, in order to prevent the printing plate from being damaged during handling, it is necessary to support the printing plate with a cardboard frame, or to fix the top and bottom ends of the printing plate onto separate supports using adhesives, etc. during the plate-making process. No particular problem arises in the prior art, in which a document is inserted between the printing plate material and the support. However, in this plate making apparatus, the plate material 34 is pressed against the thermal writing head 18 and is transported by a feeding mechanism consisting of rollers 20, 23 to 26, guide plates 27, 28, etc. It is inconvenient to apply to this apparatus a structure in which the plate material 34 is supported by a frame or whose end portion is supported by a support body.

Therefore, in the present application, in order to eliminate the above-mentioned disadvantages, the heat-sensitive stencil printing plate material 34 is pasted on another sheet-like support, and the plate material 34 is conveyed while being held on the support during the plate-making process by the thermal writing head 18. However, the plate material 34 can be peeled off from the support after plate making is completed and prior to printing. Paper or a plastic sheet is used as the support, and as a means of adhering the printing plate 34, an adhesive with a relatively weak adhesive force such as polyvinyl alcohol, or means such as pressure welding or pressure welding heating without using an adhesive are used. This allows the plate material 34 to be easily peeled off from the support.

By supporting the heat-sensitive stencil printing plate material 34 in close proximity to the support in this manner, it is possible to transfer the printing plate material 34 without any trouble even with the feeding mechanism shown in FIG. By adopting a configuration in which writing is performed with the writing head 18 and the support is then peeled off and removed, a mechanism for feeding the plate material 34 can be easily realized.

Furthermore, as in the above-mentioned plate making apparatus, the plate material 34 is pressed by the pressure roller 2o.
In a device having a mechanism for transferring the plate material 34 while being pressed against the writing head 18, it is necessary to prevent the thermoplastic resin of the plate material 34 from welding to the writing head 18 due to heat during plate making.

As a method of preventing welding, for example, as shown in FIG. 4, a heat-sensitive stencil printing plate material 34 is laminated on a support 41 such as paper or a plastic sheet, and a welding prevention layer 42 is further laminated on top of the support 41, and each layer is laminated. The support 41 and the anti-welding layer 42 are bonded using a weak adhesive or the like after the plate-making process is completed.
to be able to be peeled off and removed. In this case, the welding prevention layer 42
The thermoplastic resin is heated by the heat during plate making to the thermal writing head 18.
When transmitting the heat of the head 18 to the thermoplastic resin, it is necessary to satisfy conditions such as not reducing the sharpness of the plate by diffusing the heat 1. Welding prevention layer 42 that satisfies these conditions
For example, in order not to reduce the sharpness of plate making, a polyester film of several microns to tens of microns can be used. This film can be releasably adhered to the cryogenic stencil printing plate material 34 by the same adhesive means as described above, and can satisfy the above conditions.

As described above, the plate material sheet having a three-layer structure in which the heat-sensitive stencil printing plate material 34 is laminated on the support 41 and the welding prevention layer 42 is further laminated on the entire surface thereof is sufficient for feeding.

It has the strength to withstand, can prevent thermoplastic substances from adhering to the thermal writing head 18, and can also improve the handling of the plate material 34 before and after plate making, so that the method of the present invention can be carried out. This configuration is extremely suitable for various cases.

Further, as a method of preventing welding, as shown in FIG. 5, the surface of the heat-sensitive stencil printing plate material 34 is coated with a welding prevention agent such as silicone oil or wax to provide a welding prevention layer 51, or as shown in FIG. As shown, this can be achieved by using a heat-sensitive stencil printing plate material 61 containing the above-mentioned welding inhibitor. In this case, the thermal writing head 1 is
A thin film is formed on the surface of the plate 8 to prevent welding of the thermoplastic resin, but the amount is very small so as not to block the fine perforations formed during plate making. By doing this, the plate material 34 can be transferred to the support 41 after the plate-making process is completed.
The trouble of peeling off the welding prevention layer 42 described above can be omitted by simply peeling it off from the surface. In cases where it is difficult to apply the adhesion prevention substance to the adhesive and maintain it stably, the problem can be removed by enclosing the anti-welding substance in microcapsules made of a heat-fusible coating and mixing or applying the substance. In this case, only the microcapsules in the writing area heated by the thermal writing head are torn and the anti-welding agent is supplied to the surface of the thermal writing head, so the anti-welding agent can be supplied in the required amount to the required location. At the same time, there is no fear of changing the physical properties of the plate material.

Furthermore, as a method to prevent welding, the welding prevention layer is supplied from a supply roll, passed through the thermal writing head, and wound up with a take-up roll, so that the welding prevention layer is interposed between the plate material and the thermal writing head. Note that the present invention is not limited to the above embodiments, and can be implemented with various modifications without changing the gist.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a color sensitivity with a natural feeling close to that seen by the naked eye, and also to prevent the occurrence of a plate-making effect that is different from that seen by the naked eye due to the thermal characteristics of the coloring agent forming the original image, resulting in a printing effect that is close to that seen by the naked eye. can be obtained, and plate making from three-dimensional objects and thick originals can be performed satisfactorily.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the process procedure of an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing an example of a plate-making apparatus to which the embodiment is applied, and FIG. 4 to 6 are configuration diagrams showing different specific examples of thermal stencil printing plate materials applied to the same plate-making device,
FIGS. 7(a) and 7(b) are explanatory diagrams for explaining the conventional printing master production method. ... Plate making process 1 ... Original 2 ... Optical reading head 3 ... Mechanical optical system 4 ... Read circuit 5 ... Signal processing Circuit 6...Writing drive circuit 7...Thermal writing head 8...
・Mechanism system 9...Thermal stencil printing plate material Figure 1 Figure 2 (b) Figure 3 Figure 4 Figure 5 (b) Figure 6 ILJ) Figure 7

Claims (1)

[Claims] In a plate-making method in which fine pores are formed by selectively applying heat in an image to a heat-sensitive stencil printing plate material made by integrating a thermoplastic, shrinkable resin and a mesh-like sheet, the original image is photoelectronically A reading process in which a conversion element optically reads the signal and converts it into an electrical signal, and a plate-making process in which a thermal writing head is driven and controlled based on the electrical signal from this reading process to form fine perforations corresponding to the original image on the plate material. A method for producing a thermal stencil printing original plate, comprising: