JP2002137354A - Stencil type plate processing apparatus, method for plate processing, and control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stencil type plate processing apparatus by which reproducibility of an image of a manuscript such as letters and lines is improved and a plate with suppressed heat shrinkage can be obtained, a method for plate processing and a control program for it. SOLUTION: Timing of application of an exothermic element of a thermal head is controlled in such away that whether heat has been applied on a non- imaged part of the preceding line of a non-imaged part to be watched is discriminated and in the case when it has been applied as the result of discrimination, a time for applying the heat on the non-imaged part to be watched is shortened more than the case when it has not been applied and in addition, whether heat is going to be applied on a non-imaged part of the next line of the non-imaged part to be watched is discriminated and in the case when it is going to be applied as the result of discrimination, the time for applying the heat on the non-imaged part to be watched is shortened furthermore than the case when it is not going to be applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing technique for stencil printing, and more particularly, to a stencil printing technique for closing a plastic sheet having a large number of fine pores with a thermal head. .

[0002]

2. Description of the Related Art As a stencil sheet for stencil printing (stencil sheet), a heat sensitive stencil sheet pierced by infrared irradiation or a thermal head has been conventionally known, and an adhesive between a thermoplastic plastic film and porous thin paper is used as an adhesive. Is generally used.

[0003] As a stencil printing apparatus using a heat-sensitive stencil sheet, a single cylinder stencil printing apparatus and a simple pressing stencil printing apparatus are mainly known. In these printing apparatuses, printing is performed by extruding ink from a thin paper side of a stencil sheet through holes formed in a film corresponding to an image portion of a print image, and transferring the ink to printing paper.

[0004] The inks used in these printing devices are:
It is mainly a water-in-oil (W / O) emulsion ink. The amount of ink transfer during printing depends on the viscosity of the ink, the density of the tissue paper (adjustment of the ink passage resistance), the perforated area ratio of the film, and the printing pressure. , Printing pressure time and the like.

[0005]

However, in the conventional stencil printing system, the amount of ink transferred to the printing paper is large, and it takes time for the ink to permeate the printing paper. Was required. In other words, since the ink does not readily permeate the printing paper surface, touching the printed matter immediately after printing stains a finger or the like, or performing printing of the second color or later in multicolor printing or printing on the back side in double-sided printing. In addition, there is a problem that the ink is transferred to a rubber roll or the like of a printing machine, and the transferred ink is transferred to a printing paper to stain a printed matter. Therefore, it is necessary to wait a long time (for example, about 10 to 20 minutes) before moving to the next process. There was an inconvenience.

In order to solve the above-mentioned problems and to obtain quick drying of the ink, it is effective to reduce the amount of transferred ink. Therefore, in the conventional stencil printing system, (1) the density of the thin paper is increased. To increase the resistance to ink passage,
(2) In plate making using a thermal head, various measures have been taken, such as minimizing the size of the perforated area by reducing the size of the heating element of the thermal head, and (3) minimizing the printing pressure times the printing pressure time.

However, if the ink transfer amount is reduced by the above (1) to (3), the resulting image will be blurred and the image quality such as solid uniformity will be deteriorated, so that the image quality and the quick drying property are satisfied simultaneously. It was difficult to perform printing.

[0008] That is, in the above (1), when the density of the thin paper is increased, perforation failure occurs at the time of plate making, and the portion impairs ink permeability. In perforation, heat generated from the heat generating part of the thermal head is transferred to the film and the film melts and contracts.However, if there are many contacts between the film and the thin paper, the film melt easily accumulates there, Prone to poor drilling.

In addition, it is difficult to control the distribution of apertures in the method of producing thin paper, and since the distribution of the aperture area is large, the perforated area tends to vary in plate making using a thermal head. There are portions having good and poor ink passage properties, and it is difficult to uniformly reduce the amount of transferred ink.

Further, since it is difficult to form an image in a portion having a small perforated area, if the ink transfer amount is adjusted to this portion, an ink transfer amount becomes excessive in a portion having a large perforated area and good ink permeability, and the portion is transferred to printing paper. The drying properties of the washed ink deteriorate.

In the above (2), it is necessary to increase the integration of the heating elements of the thermal head and to reduce the size of the heating elements. At present, the element density (resolution) of the thermal head is six.
Although it is realized up to 00 dpi, the hole diameter to be perforated is still in the range of about 20 to 40 μm, and this range is insufficient for controlling the ink transfer amount.

Since thin paper has a low resistance to the passage of ink, it is conceivable to use high-viscosity ink to reduce the amount of ink transferred to paper. However, when a high-viscosity ink is used, even if the amount of transferred ink can be reduced, the permeability of the ink to paper deteriorates, and consequently the drying property cannot be improved. Therefore, it is necessary to increase the permeability of the ink into the printing paper by using a low-viscosity ink to increase the drying property and to suppress the ink transfer amount to a small value.

[0013] However, in order to limit the amount of ink transfer with a low-viscosity ink, the diameter of the perforations must be generally set to 20 µm or less. It has to be increased to 600 dpi or more to further reduce the size of the heating element of the thermal head. Although this is technically feasible, it leads to a significant increase in the cost of the thermal head, and furthermore, it is necessary to improve the level of peripheral technologies such as securing the durability of the thermal head, improving the yield, and increasing the film sensitivity of the heat-sensitive stencil paper. Is not a viable solution.

In the above (3), it is possible to control the ink transfer amount as an average value. However, as described above, since the aperture distribution of the thin paper is large and the perforated area by the thermal head varies, there is a problem. The problem that the ink transfer amount becomes partially non-uniform and the drying property is poor in the portion where the ink transfer amount is large cannot be solved.

Therefore, a stencil printing method that simultaneously satisfies imageability and quick drying without using a reactive ink such as an ultraviolet curable ink has been proposed at present.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. In order to enhance the ink drying property in stencil printing, an ink using a low-viscosity ink having high permeability to printing paper is used. An object of the present invention is to provide a stencil printing machine, a stencil making method, and a control program for obtaining a stencil printing plate capable of controlling the amount of transfer and capable of obtaining a printed matter having excellent image properties and quick drying properties. And

[0017]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a microporous plastic sheet having micropores on the order of submicrons (hereinafter abbreviated as "microporous sheet" or simply "sheet"). Is used as a stencil sheet for stencil printing, and the heating element such as a thermal head shrinks and melts to the surface layer or the inside of the microporous sheet to block the microporosity and form an ink non-passing part in the non-image area. Makes it possible to appropriately control the amount of low-viscosity ink (for example, viscosity of 0.001 to 1 Pa · s) having high permeability to printing paper, and as a result, the conventional ink (viscosity) 2 to 10 Pa · s), the ink permeation time can be greatly reduced, and quick drying can be realized. It is to control the heating timing of, it is possible to improve reproducibility of an original image such as a character or a line, it was and found that it is possible to suppress heat shrinkage.

That is, according to the present invention, a heating element of a thermal head arranged or moved in a main scanning direction relative to a microporous plastic sheet is moved in a sub-scanning direction, and a non-image area of a desired print image is formed. Apply heat necessary for melting to the surface or inside in a negative image form, and close the micropores of the microporous plastic sheet where heat was applied by heat shrinkage or heat melting to form an ink non-leaching portion (1) It is determined whether or not heat has been applied to the non-image portion of the line preceding the non-image portion of interest. The application time of heat to the non-image area of interest is shortened, and it is further determined whether or not the non-image area of the line next to the non-image area of interest is to be applied. , The above attention than the case of applying The application timing of the heating element is controlled so as to further shorten the time of applying heat to the non-image portion to be heated. (2) Whether to apply heat to the non-image portion adjacent to both sides of the target non-image portion When applying the heat to at least one of the non-image portions, the heat generation is performed so as to shorten the application time of the heat to the noted non-image portion as compared with a case where both are not applied. It is characterized in that the application timing of the element is controlled.

Since the above (1) and (2) each provide a sufficient action and effect, plate making may be performed by combining (1) and (2), or (1) Alternatively, plate-making may be performed only in one of (2).

In the present invention, the type of thermal head may be a line type thermal head or a serial type thermal head.

The resistor of the thermal head may be a thin-film thermal head mainly formed by sputtering or a thick-film thermal head formed by a thick-film printing method.

In the present invention, the mechanism by which the micropores of the microporous sheet are closed by the heat generated by the thermal head will be described. The temperature of the microporous sheet rises due to heat generation from the thermal head and the like, and from a temperature lower than the melting point of the microporous sheet, the dimensions are thermally shrunk to release residual stress due to stretching during film formation. Go. At this time, the micropores are closed by heat shrinkage. However, if the heat generation temperature of the thermal head is low and the heat shrinkage is insufficient, the fine holes cannot be completely closed.

When the temperature further rises and reaches the melting point of the sheet, the plastic is melted up to the surface layer or the inside of the sheet, and the micropores are completely closed. However, even if the melting point is not reached, if the sheet is sufficiently thermally shrunk, at least the micropores on the plate making surface in contact with the thermal head are completely closed.

That is, the degree of blockage of the micropores and the degree of heat shrinkage of the sheet due to plate making depend on the heat generation temperature distribution of the thermal head (or the heat generation temperature distribution received by the microporous sheet).

Here, factors that control the heat generation temperature of the thermal head include "shape and structure of heat generating element" and "applied voltage and application time for generating heat". When the thermal head is driven under the condition, the heat storage state of the thermal head differs depending on the “heat generation pattern (image pattern) and the number of times of heat generation”. That is, the gist of the present invention is to control the application timing of the thermal head according to the image pattern of the print image, thereby preventing excessive blockage of the microporous sheet and suppressing excessive heat shrinkage of the microporous sheet. .

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of a stencil type stencil making machine according to the present invention, and schematically shows a state in which a microporous sheet 10 is thermally melted by a thermal head 20 to make a stencil. ing. The microporous sheet 10 is sent to an image forming section composed of a thermal head 20 and a platen roller 21 by an optional feed roller (not shown). Then, the surface (plate making surface) of the microporous sheet 10 is contracted and melted by the heat generated by the heat generating element 22 of the thermal head 20 that generates heat based on the image signal, and the closed portion (non-image portion) 11 in which the fine holes are closed. Is provided. Here, the microporous sheet 10 is provided with a release layer 12 so that fusion to the thermal head 10 does not occur.

Using the microporous sheet 10 made as described above, the plate making surface is overlapped with printing paper, and a low-viscosity ink is supplied from the opposite side (non-plate making surface) of the microporous sheet 10 to apply pressure. Then, the ink exudes from the fine holes (not closed and corresponds to the image area) in the non-plate making portion of the plate making surface, and is transferred to the printing paper to perform stencil printing.

In the above plate making, the non-image area 11
In order to prevent the leaching of the ink, it is sufficient that the pores are closed at least on the plate making surface and do not penetrate from one surface of the microporous sheet 10 to the other surface. That is, pores may be left on the entire non-plate making surface.

The specific printing method is not particularly limited. For example, a material having open cells that can be impregnated with ink (eg, natural rubber, synthetic rubber sponge rubber, or synthetic resin foam) is impregnated with ink. Is overlaid on the non-plate making surface of the microporous sheet 10 on which the plate making is completed, the plate making surface and the printing paper are aligned and pressed, whereby the ink is transferred to the printing paper and stencil printing is performed.

Further, like a single cylinder type stencil printing machine, a perforated microporous sheet may be wound around a printing drum and ink may be supplied from inside the printing drum to perform continuous printing. Press printing may be performed using a household simple stencil printing machine such as that manufactured by Kogyo Co., Ltd.).

The microporous sheet 10 is made of a non-elastic resin film and is a microporous stencil sheet used for stencil printing using a low-viscosity ink having a viscosity of 0.001 to 1 Pa · s. It is characterized in that the thickness is 1 to 100 μm for up to 600 seconds.

The lower the viscosity of the ink, the higher the permeability to the printing paper. If the viscosity exceeds 1 Pa · s, sufficient permeability to the printing paper cannot be obtained. When higher ink drying property (quick drying property) is required, an ink having a viscosity of 0.1 Pa · s or less is preferably used. Further, the surface tension of the ink is 5 from the viewpoint of ink passage.
× ¹⁰ -2 N / m or less, more preferably not more than 4 × ¹⁰ -2 N / m. The colorant of the ink may cause clogging depending on the type of pigment depending on the pore diameter of the micropores of the microporous sheet 10. In the case of pigment, use a finely dispersed pigment or use a dye. Is preferred. In addition, components such as an ink vehicle and additives are not particularly limited, and are not particularly limited to stencil printing inks. For example, water-based or oil-based inks for inkjet or stamping are preferably used. Can be.

In order to control the transfer amount of such a low-viscosity ink, the air permeability in the above range (under a constant pressure difference,
Degree of air passage: Gurley Densometer (JI
SP8117); the same applies hereinafter)
0 is used. If the air permeability exceeds 600 seconds, it is not practical because the ink is difficult to pass. On the other hand, if it is shorter than 1 second, it becomes difficult to control the amount of ink transfer.

The thickness of the microporous sheet 10 is within the above range. If the thickness exceeds 100 μm, the ink permeability deteriorates and sufficient solid uniformity cannot be obtained, and the rigidity of the thermal head during plate making becomes too strong. Etc., the contact property with the heating element and the operability are reduced. On the other hand, if the thickness is less than 1 μm, the required strength of the microporous sheet 10 cannot be secured, so that the practicability is poor. From the viewpoint of improving operability, those having a thickness of 10 μm or more are preferably used.

The size of the micropores of the microporous sheet 10 can be arbitrarily selected according to the viscosity and surface tension of the low-viscosity ink to be used, but the average pore size (measured with a mercury intrusion porosimeter; the same applies hereinafter) Is preferably 0.01 μm or more from the viewpoint of ink permeability, and is preferably about 10 μm or less, more preferably 0.01 μm or less, from the viewpoint of controlling the transfer amount when the viscosity of the low-viscosity ink is low.
〜1 μm is selected.

Further, the porosity of the microporous sheet is preferably 40% or more from the viewpoint of ink permeability, and is preferably 90% or less from the viewpoint of strength, but is not limited thereto. . Here, the porosity is determined from the specific gravity (A) of the film material constituting the microporous sheet 10 and the specific gravity (B) of the microporous sheet 10 using the following equation.

[0038]

Porosity = (100−B / A) × 100 (%) The surface roughness of the microporous sheet 10 is determined from the viewpoint of contact with the heating element 22 such as the thermal head 20 during plate making.
Rz (ten-point average roughness: JIS B 0601) is preferably 20 μm or less. Also, if the surface roughness is too large, the unevenness between the printing paper and the microporous sheet 10 becomes large, and an excessive amount of ink is supplied to the gap, so that the ink transfer amount may be increased more than necessary. is there.

The polymer of the non-elastic resin film constituting the microporous sheet 10 is not particularly limited, but a thermoplastic resin can be preferably used in order to enable plate making by hot melting. Specifically, for example, polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); 66 nylon;
Polyamides such as nylon 12; chlorine-based resins such as polyvinyl chloride, polyvinylidene chloride or copolymers thereof;
Or, polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE)
And the like. Among these, polyolefins, especially polyethylene, can be preferably used. These resins can be used alone or
A multilayer structure can be formed by combining more than one kind.

As an example of polyethylene that can be preferably used for the microporous sheet 10, see JP-A-11-13.
No. 0900, polyethylene for a microporous polyethylene membrane. That is, high-density to low-density various polyethylene homopolymers and copolymers having α-olefin units such as propylene, butene, pentene, hexene, and octene (linear copolymerized polyethylene) can be preferably used. The quantity is
It is preferably about several mol% (for example, 4 mol% or less) based on ethylene units. Polypropylene, high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, polyolefin of ethylene-propylene copolymer can also be arbitrarily mixed and used, and the content of polyolefin other than polyethylene at that time is 30%. It is preferable that the content be not more than weight%.

The molecular weight of the polymer is not particularly limited, and is arbitrarily selected with respect to the type of the resin from the viewpoint of the breaking strength of the sheet, the operability at the time of production, and the like. For example, in the case of polyethylene, its weight average molecular weight (Mw: measured using a calibration curve of standard polystyrene by gel permeation chromatography; the same applies hereinafter) is 100,000 or more from the viewpoint of breaking strength at the time of sheet stretching. It is preferably about 4,000,000 or less in view of melt productivity at the time of film formation, and 200,000 to 7
More preferably, the molecular weight is from 10,000 to 250,000 to 500,000. The weight average molecular weight can also be adjusted to a preferred range by means such as blending or multi-stage polymerization.

The above-mentioned resin may further contain, if necessary, a dispersant, a thixotropic agent, an antifoaming agent, a leveling agent, a diluent, a plasticizer, an antioxidant, a filler, a coloring agent and the like. The additive may be contained in a range that does not inhibit the formation of micropores and the like.

As a method (film forming method) of the sheet 10 (stencil paper) using such a resin, an ordinary method such as a casting method (T-die method) using a molten polymer can be used. Alternatively, a sheet obtained by sintering resin particles may be used.

The method for forming micropores in the obtained sheet 10 is not particularly limited, and a general microvoid generation method or a solvent extraction method can be used. Specifically, for example, the sheet 10 is microcrystallized by heat treatment (annealing) and is stretched in at least a uniaxial direction, so that the difference in the elastic modulus between the crystalline region and the non-crystalline region is formed at the boundary between the crystalline region and the non-crystalline region. It can be used to make small crevices. When the sheet 10 is formed, a filler is mixed with the molten polymer, and after the sheet 10 is formed, the filler may be stretched at least in one axis direction to form a fine tear at the filler portion. Alternatively, after the polymer and the solvent are heated and melted to form the sheet 10, the sheet is cooled and the solvent is phase-separated, and the solvent may be stretched (at this time, the solvent is extracted before or after the stretching. ). At that time, an inorganic filler may be added to increase the dispersibility of the resin and the porosity.

The microporous sheet 10 can be produced as described above, or a commercially available porous plastic sheet, for example, “Hipore” of Asahi Kasei Kogyo Co., Ltd., “NF Sheet” of Tokuyama Corp. Perforated sheet), Porum (PE-based microporous sheet), Nitto Denko Corporation's Sunmap (PE sintered sheet), Microtex (tetrafluoroethylene resin sheet), Breslon (PE Perforated sheet), Maruzen Polymer Co., Ltd.'s "Permilan" (polyolefin-based porous sheet), Mitsui Toatsu Chemicals Co., Ltd.'s "ESPOIR" (polyolefin-based porous sheet), Ube Industries, Ltd.'s "UPORE" (PE-based) It is also possible to use a microporous sheet).

The microporous sheet 1 used in the present invention
0 is preferably stretched.

The plastic sheet is stretched in a certain direction at the time of production, and then when heated,
In order to release residual stress due to stretching during film formation, it has the feature that it easily shrinks in the direction opposite to the stretching direction,
This is because the use of a sheet to which heat shrinkage has been imparted by stretching increases the ability to close micropores due to thermal melting when performing plate making with the heat of the thermal head 20.

Further, in any of the above-described production methods, heat treatment may be performed in-line or in a separate step in order to adjust the heat shrinkage of the sheet 10. Further, it is preferable that the sheet 10 includes an antistatic agent in order to prevent conveyance failure due to static electricity. Various surfactants can be used as the antistatic agent. Specifically, anionic surfactants such as fatty acid salts, higher alcohol sulfate salts, fatty acid amines, fatty acid amide sulfonates, fatty acid amide sulfates, fatty alcohol phosphate ester salts, etc .; Cationic surfactants such as quaternary ammonium salts and alkylpyridium salts; Nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenol ethers, polyoxyethylene alkyl esters, and sorbitan alkyl esters; And an amphoteric surfactant such as an imidazoline derivative, a higher alkylamine type (betaine type), a sulfate ester phosphate type, and a sulfonic acid type. These can be used alone or in combination of two or more.

The antistatic agent may be kneaded into the resin before molding to be included in the film, or may be applied to the surface after the film is molded. The application method is not particularly limited. For example, it may be diluted with a solvent such as water or alcohol, applied using a spray, dipping, brush, roll coater or the like, and then dried. The coating may be performed at any stage before and after the formation of the micropores. The content or application amount of these is not particularly limited, and may be arbitrarily set as long as the purpose of each addition is sufficiently achieved and ink permeability is not hindered.

Further, on the surface of the sheet 10, one or two kinds of silicone, fluorine, wax, or activator are used so that the melt of the microporous sheet 10 is not fused to the heating element of the thermal head 20. A release agent comprising the above,
A release agent containing a silicone phosphate may be applied. The method of applying the release agent to the sheet 10 is not particularly limited. For example, a component including a release agent is dispersed or dissolved in an arbitrary solvent, and a roll coater, a gravure coater,
The coating may be performed using a reverse coater, a bar coater, or the like, and then the solvent may be evaporated.

The coating may be performed before or after the formation of the micropores. The thickness of the release agent to be formed is such that sufficient release properties are obtained without inhibiting ink passage.
It is preferably about 0.001 to 0.5 g / m ² .

The release layer containing the release agent as described above may further contain an antistatic agent (described above), a hot-melt substance, a binder resin, and the like, as long as the object of the present invention is not impaired.

However, in the case of making a microporous sheet as a stencil sheet by the above-described plate making method, unlike the conventional plate making method of positive plate making, it is a negative plate making. In the case of an image, for example, in the case of a print image having many characters and lines and many white image portions, or a print image having few solid black image portions, the heat generation frequency (number of times) of the heating element of the thermal head is extremely high. Therefore, there is a concern that the thermal head easily accumulates heat, and the heat generation temperature of the thermal head may be significantly higher than a desired temperature.

In general, the temperature of the heating element of the thermal head is slower than the temperature rising rate, and once heated, it takes time to recover to the original temperature. Therefore, when the same heating element is continuously applied, the plate making of the next line is started before the thermal energy applied to the heating element is sufficiently diffused and released, so that the thermal energy is gradually applied to the heating element. It accumulates, and as a result, the exothermic temperature rises sharply.

Therefore, if the heat generation temperature of the thermal head becomes high and the micropores are closed more than necessary,
For example, in the case of "characters" or "thin lines", the ink transfer portion (ink passing portion) becomes narrower than the desired line width, or ink does not pass at all, and characters and lines cannot be read. Is a factor that degrades the quality of printed matter.

Further, when the thermal contraction of the microporous sheet becomes large due to the heat storage of the thermal head during plate making, there is a problem that the dimensional reproducibility of the finished printed matter with respect to the original is deteriorated. When the heat-shrinkable microporous sheet is conveyed in a plate making apparatus or a printing apparatus, or when it is applied to a printing drum, the microporous sheet may be wrinkled.

To solve these problems, by controlling the timing of heating the microporous sheet by the thermal head, the reproducibility of the original image such as characters and lines can be improved, and the thermal shrinkage can be suppressed. Hereinafter, the control of the heating timing for the microporous sheet will be described in detail.

FIGS. 2 to 6 schematically show points (non-image area 11) to which the heating element 22 of the thermal head 20 applies heat in the main scanning direction m and the sub-scanning direction n in the present invention. FIG. 9 is an image diagram in which a current application point (hereinafter referred to as a “target non-image portion”) is denoted by D.
_{m · n} , the non-image portion of the line immediately before the non-image portion of interest is D _{m · n−1} , and the non-image portion of the next line is D _{m · n + 1.} The non-image portion to the left of the image portion is D _{m−1 · n} , and the non-image portion to the right is D _{m + 1 · n}
It is.

The present invention relates to a microporous plastic sheet 10
On the other hand, the heating element 22 of the thermal head 20 arranged or moved in the main scanning direction m is relatively moved in the sub-scanning direction n to melt the surface or the inside in the non-image area 11 of a desired print image. When the necessary heat is applied in the form of a negative image, and the micropores 10 of the microporous plastic sheet in the portion where the heat is applied are closed by heat shrinkage or heat melting to form an ink non-leachable portion, (1) It is determined whether or not heat has been applied to the non-image portion D _{mn-1 of the} line before the noted non-image portion D _mn , and if the result of the determination indicates that heat has been applied, the case has not been applied. The application time of heat to the noted non-image portion D _mn is shorter than that of the noted non-image portion D _mn .
_{m · n + 1} is determined whether applied will, if not judged result is applied scheduled, to further shorten the even heat application time to the non-image portion D _{m · n} of the target than the applied schedule (2) The non-image portions (D) adjacent to both the non-image portions D _{m and n} of interest are controlled.
_{m-1 · n} or D _{m + 1 · n} ) to determine whether or not to apply heat. As a result of the determination, at least one of the non-image areas (D _{m-1 · n} or D _{m + 1 · n} ) is applied. When applying, the application timing of the heating element 22 is controlled such that the application time of the heat to the noted non-image area D _mn is shorter than when both are not applied. .

That is, according to the control condition of the above (1),
Non-image part D of the line before the non-image part D _mn of interest
Determine whether the application of _mn-1 is "ON" or "OFF",
In the case of “ON” (for example, FIGS. 2 to 3), “OFF”
In the case of (for example, FIGS. 4 to 6), by driving the thermal head 20 with a shorter heat generation time (application time), it is possible to suppress an increase in the heat generation temperature of the thermal head 20. That is, since the heat generation temperature of the thermal head 20 can be prevented from rising above a desired temperature and heat can be generated at a constant temperature, heat shrinkage due to plate making can be suppressed, and the micropores of the microporous sheet 10 can be further reduced. Can be improved, and the reproducibility of “characters and thin lines” can be improved.

Further, at this time, the non-image area D of interest
The application of the non-image portion D _{mn + 1} of the line next to _mn is “O
N "or" OFF ", and in the case of" OFF "(FIG. 3), the thermal head 20 is driven with the heat generation time (application time) further shorter than in the case of" ON "(FIG. 2). Thereby, when the non-image portion D _{mn + 1} of the next line is not scheduled to be applied, the heat generation temperature of the non-image portion D _mn of interest is suppressed, and the micro holes to be left in the next line are further closed. To prevent them from getting lost. Therefore, the reproducibility of “characters and thin lines” can be further improved at the boundary between the image portion (print portion) and the non-image portion (non-print portion).

[0062] Similarly, the control condition (2), non-image portions of both sides of the non-image portion D _{m · n} of interest (D
_{m-1 · n} or D _{m + 1 · n} ) is determined to be “ON” or “OFF”, and as a result of the determination, at least one of the non-image portions (D _{m−1 · n} or D _{m + 1 · n} ) is determined. _n )
Is “ON” (for example, FIGS. 4 and 5), the application time of heat to the noted non-image portion D _mn is shorter than when both are “OFF” (for example, FIG. 6). By doing so, it is possible to suppress an increase in the heat generation temperature of the thermal head 20.

Since the above (1) and (2) each provide a sufficient action and effect, plate making may be performed by combining (1) and (2), or (1) Alternatively, plate-making may be performed only in one of (2).

The number of objects to be discriminated in the “previous line”, “next line” or “left adjacent” or “right adjacent” direction of the target non-image portion D _mn is determined. Is not particularly limited, a control method corresponding to various application patterns is defined in advance, and a setting table of the application time is provided such that the heat generation temperature is within a certain range in any application pattern, and based on the values in the table. In this case, the application time may be controlled.

In the above (1) and (2), the ratio of the magnitude of the application time is not particularly limited, and the optimal application time can be adjusted according to the operating environment and the like.

In general, the thermal head 20 has an ambient temperature and a heat storage state (these are taken as an environmental temperature).
Therefore, when driven under the same application condition, the heat generation temperature may be significantly different. Therefore,
A setting table may be provided so that the heat generation temperature may be within a certain range, regardless of the environmental temperature, and the application time may be controlled based on the value of the table. At this time, the environmental temperature can be determined by a thermistor or the like provided on the thermal head 20, as is well known.

[0067]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a stencil making machine, a stencil making method, and a control program according to the present invention will be described below. Incidentally, the present invention is not limited to this embodiment unless departing from the technical idea of the present invention.

FIG. 7 is a flowchart showing a processing procedure of a stencil making operation in the stencil making machine according to the present invention.
For example, the control program for controlling the processing operation of the stencil making machine according to the present invention controls the operation according to the following processing procedure. FIG. 8 is a diagram exemplifying a pattern of the application time of the thermal head 20, and FIGS.
FIG. 4 is a diagram illustrating an example of an application time setting table.

When plate making is started, the thermal head 20
If there is a thermistor, the value (environmental temperature) is read, and the application time is set based on the preset value of the application time setting table (Step 01 to Step 0).
2).

Next, when an application start signal is input (Step
03), the main application is turned “ON” (Step 04), and FIG.
As shown in (a) to (c), an application corresponding to the main application time is performed.

When the main application is completed (Step 05), next, the history data is determined (Step 06). That is, the "previous line" D _mn-1 or the "next line" D _{mn + 1} or "left adjacent" D of the non-image portion D _mn of interest.
_It is determined whether the thermal application is “ON” or “OFF” in the direction of _{m−1 · n} or “next right” D _{m + 1 · n} , and the application for the history is performed based on the setting value of the application time setting table (FIG. 8). In the example, it is determined whether to perform “history application 1” and “history application 2”.

When the application for the history is performed (Step 07),
The application time for the history is set based on the setting value of the application time setting table, and the application for the history is turned “ON” following the main application (Step 08).

When the application for the history is completed (Step 09), it is determined whether to make a plate or to finish the plate making (Step 1).
0).

FIG. 8 illustrates an application time pattern. FIG. 8A shows an application pattern having the shortest application time (pattern A), in which only the main application is performed. FIG. 2B shows the next shortest application pattern (pattern B), in which main application and history application 1 are performed, and FIG. 2C shows the application pattern with the longest application time. A cage (pattern C) is a pattern in which main application and history application 1 and history application 2 are performed.

[0075] Figure 9 shows the above (1) to shows an example of application time setting table in the control conditions shown, the non-image area D _{m · n} of the previous line of the non-image region D _{m · n} of interest _-1
When both the non-image portion D _{m · n + 1 of the} next line are “ON”, the “application pattern B”
_When only _{m · n−1} is “ON”, “application pattern A” with the shortest application time, and non-image area D of the previous line
_When only _{m · n−1} is “OFF”, “application pattern C” having the longest application time is set.

Similarly, FIG. 10 shows an example of an application time setting table under the above (2) control conditions.
Non-image area D to the left of non-image area D _mn to be focused on
_{Both m−1 · n} and the non-image area D _{m + 1 · n on the} right are “O
In the case of “FF”, the “application pattern C” having the longest application time, the left non-image part D _{m−1 · n} and the right non-image part D
_When at least one of _{m + 1 · n} is “ON”, “application pattern B” is set.

[0077] Figure 11 shows the above (1) and (2) shows an example of application time setting table when a combination of control conditions, the non-image of the previous line of the non-image region D _{m · n} of interest The line portion D _mn-1 and the non-image portion D _{mn + 1 of the} next line
Are both “ON”, “application pattern B” regardless of the non-image portions on both sides. Non-image area D mn _{- 1 of the} previous line
When only “ON” is set, “application pattern A” having the shortest application time regardless of the non-image portions on both sides.

The non-image area D _{mn-1 of the} previous line is "OF
In the case of F ", and attention to the left of the non-image portion D _{m · n} non-image portion D _{m-1 · n} and the non-image area of the right D _{m + 1 · n} are both" OFF " In this case, at least one of the “application pattern C” having the longest application time and the non-image area D _{m−1 · n} on the left and the non _- image area D _{m + 1 · n on} the right is “O”.
In the case of "N", it is defined that "application pattern B" is set.

FIG. 12 is a flowchart showing an example of a processing procedure under the control conditions shown in the above (1). Non-image part D of the line before the non-image part D _mn of interest
_It is determined whether _mn-1 is "ON" or "OFF" (Step 2).
1) In the case of “OFF”, the “application pattern C” having the longest application time (Step 25), and the non-image area D _mn−1 is “O”
N ", the non-image area D of the next line
_It is determined whether _{mn + 1} is “ON” or “OFF” (Step 2)
2) In the case of “OFF”, “application pattern A” having the shortest application time (Step 23), non-image area D of the next line
_{If mn + 1} is "ON", "application pattern B" is set (Step 24).

FIG. 13 is a flowchart showing an example of a processing procedure under the control conditions shown in the above (2). It is determined whether the non-image portion D _{m + 1 · n on} the right of the target non-image portion D _mn is “ON” or “OFF” (Step 31), and “ON”
In the case of (1), the “applied pattern B” (Step 35) is used. If the non-image area D _{m + 1 · n on} the right is “OFF”, the non-image area D _{m−1 · n on the} left is “ON”. "OFF" or "OFF" (Step 32). If "OFF", the "applied pattern C" (Step 33) is set, and the non-image area _Dm- 1.n on the left is "O".
"N", "application pattern B" is set (Step
34).

FIG. 14 is a flowchart showing an example of a processing procedure when the control conditions shown in the above (1) and (2) are combined. Non-image portion D _{m · n-1} of the previous line of the non-image region D _{m · n} of interest is to determine the "ON" or "OFF" (Step 41), in the case of "ON", the following additional It is determined whether the non-image portion _{Dm · n + 1 of the line} is “ON” or “OFF” (Step 42). If “OFF”, the “application pattern A” having the shortest application time (Step 43) is selected. When the non-image portion _{Dm · n + 1} is “ON”, “application pattern B” is set (Step 44).

In the discrimination in Step 41, the non-image portion D of interest
non-image areas of the previous line of _{m · n D m · n- 1} is "OFF"
In the case of further, non-image area D _{m + 1 · n} to the right of the non-image portion D _{m · n} of interest is to determine the "ON" or "OFF" (STEP 45), when the "ON" Is “application pattern B” (Step 49), and the non-image area D _{m + 1 · n on} the right is “OF
In the case of “F”, it is determined whether the non-image area D _{m−1 · n on the} left is “ON” or “OFF” (Step 46).
In the case of "F", "application pattern C" is set (Step 47), and in the case where the left non-image area _Dm- 1.n is "ON", "application pattern B" is set (Step 48).

[0083]

According to the present invention, the heat generation time (application time) can be controlled by the pattern of the print image (the previous and next lines of the non-image area of interest and the application pattern of the non-image area on both sides). In addition, it is possible to suppress an increase in the heat generation temperature of the thermal head. That is, since the heat generation temperature of the thermal head can be prevented from rising above a desired temperature, and heat can be generated at a constant temperature, heat shrinkage due to plate making can be suppressed, and the micropores of the microporous sheet are further reduced. And the reproducibility of “characters and thin lines” can be improved. Accordingly, it is possible to provide a stencil-type plate-making apparatus, a plate-making method, and a control program therefor that can enhance the reproducibility of a document image such as characters and lines and can obtain a plate with reduced heat shrinkage.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a state in which plate making is performed using a thermal head as an embodiment of a stencil type plate making apparatus and a plate making method according to the present invention.

FIG. 2 is an image diagram schematically illustrating an example of a heat generation pattern in a main scanning direction and a sub scanning direction of the thermal head according to the present invention.

FIG. 3 is an image diagram schematically showing an example of a heat generation pattern of a thermal head in a main scanning direction and a sub-scanning direction in the present invention.

FIG. 4 is an image diagram schematically showing an example of a heat generation pattern of a thermal head in a main scanning direction and a sub scanning direction in the present invention.

FIG. 5 is an image diagram schematically illustrating an example of a heat generation pattern of the thermal head in the main scanning direction and the sub scanning direction in the present invention.

FIG. 6 is an image diagram schematically showing an example of a heat generation pattern in a main scanning direction and a sub scanning direction of the thermal head according to the present invention.

FIG. 7 is a flowchart showing an example of a stencil making process of a stencil making machine and a control program thereof according to the present invention.

FIG. 8 is an image diagram exemplifying a pattern of an application time of a thermal head for controlling a heat generation time (application time) by a pattern of a print image.

FIG. 9 is a layout diagram illustrating an example of an application time setting table for controlling a heat generation time (application time) according to a pattern of a print image.

FIG. 10 is a layout diagram illustrating an example of an application time setting table for controlling a heat generation time (application time) according to a pattern of a print image.

FIG. 11 is a layout diagram illustrating an example of an application time setting table for controlling a heat generation time (application time) according to a pattern of a print image.

FIG. 12 is a flowchart illustrating an example of a control processing procedure for controlling a heat generation time (application time) according to a pattern of a print image.

FIG. 13 is a flowchart illustrating an example of a control processing procedure for controlling a heat generation time (application time) according to a pattern of a print image.

FIG. 14 is a flowchart illustrating an example of a control processing procedure for controlling a heat generation time (application time) according to a pattern of a print image.

[Explanation of symbols]

 10. Microporous plastic sheet 11. Closed part (non-image area) 20. Thermal head 21. Platen roller 22. Heating element

Claims (9)

[Claims] 1. A heating element of a thermal head which is arranged or moved in a main scanning direction relative to a microporous plastic sheet is moved in a sub-scanning direction, and a surface or an inside of a non-image area of a desired print image is formed. A stencil plate making a negative image by applying heat necessary for melting until the heat is applied, and closing the micropores of the microporous plastic sheet where the heat is applied by heat shrinkage or heat melting to form an ink non-leaching portion. The device, wherein it is determined whether or not heat has been applied to the non-image portion of the line preceding the non-image portion of interest. The application time of heat to the non-image area is shortened.Furthermore, it is determined whether or not the non-image area of the line next to the target non-image area is scheduled to be applied. The above-mentioned non- Stencil type plate-making apparatus characterized by controlling the application timing of the heating element so as to further reduce the heat application time of the line portion. 2. A heating element of a thermal head which is arranged or moved in a main scanning direction relative to a microporous plastic sheet is moved in a sub-scanning direction, and a surface or an inner portion of a non-image area of a desired print image is formed. Stencil plate making a non-ink portion by applying heat necessary for melting to a negative image shape, and closing the micropores of the microporous plastic sheet in the portion to which the heat is applied by heat shrinkage or heat melting. A device, which determines whether or not to apply heat to the non-image portion on both sides of the non-image portion of interest, and when applying the heat to at least one of the non-image portions, A stencil type plate making apparatus characterized in that the application timing of the heating element is controlled so that the application time of heat to the noted non-image area is shorter than when no voltage is applied. 3. A heating element of a thermal head which is arranged or moved in the main scanning direction relative to the microporous plastic sheet is moved in the sub-scanning direction, and the surface or the inside of the non-image portion of a desired print image is formed. A stencil plate making a negative image by applying heat necessary for melting until the heat is applied, and closing the micropores of the microporous plastic sheet where the heat is applied by heat shrinkage or heat melting to form an ink non-leaching portion. The device, wherein it is determined whether or not heat has been applied to the non-image portion of the line preceding the non-image portion of interest. The application time of heat to the non-image area is shortened.Furthermore, it is determined whether or not the non-image area of the line next to the target non-image area is scheduled to be applied. The above-mentioned non- Further short heat application time of the line portion, when the non-image areas of the previous line is not already applying heat,
A determination is made as to whether or not heat is to be applied to both non-image portions adjacent to the noted non-image portion, and if both are applied to at least one of the non-image portions as a result of the determination, a case where both are not applied A stencil-type stencil making apparatus, wherein the application timing of the heating element is controlled so as to further shorten the application time of the heat to the noted non-image area. 4. A heating element of a thermal head which is arranged or moved in the main scanning direction relative to the microporous plastic sheet is moved in the sub-scanning direction, and the surface or inside of the non-image area of a desired print image is formed. For stencil printing, heat necessary for melting is applied in the form of a negative image, and the micropores of the microporous plastic sheet at the portion where the heat is applied are closed by heat shrinkage or heat melting to form an ink non-leaching portion. A plate making method for a plate, in which it is determined whether or not heat has been applied to a non-image portion of a line in front of a non-image portion of interest. The application time of the heat to the noted non-image portion is reduced, and further, it is determined whether or not the non-image portion of the line next to the noted non-image portion is scheduled to be applied. Is higher than the Plate making method characterized by further shortening the heat application time of the non-image areas to. 5. A heating element of a thermal head which is arranged or moved in a main scanning direction relative to a microporous plastic sheet is moved in a sub-scanning direction, and a surface or an inner portion is formed in a non-image area of a desired print image. For stencil printing, heat necessary for melting is applied in the form of a negative image, and the micropores of the microporous plastic sheet at the portion where the heat is applied are closed by heat shrinkage or heat melting to form an ink non-leaching portion. A plate making method, comprising: determining whether to apply heat to a non-image portion adjacent to a non-image portion of interest, and applying the heat to at least one of the non-image portions. Wherein the time for applying heat to the noted non-image area is shorter than in the case where neither is applied. 6. A heating element of a thermal head, which is arranged or moved in the main scanning direction, relative to the microporous plastic sheet in the sub-scanning direction, and is moved to the surface or in the non-image area of a desired print image. For stencil printing, heat necessary for melting is applied in the form of a negative image, and the micropores of the microporous plastic sheet at the portion where the heat is applied are closed by heat shrinkage or heat melting to form an ink non-leaching portion. A plate making method for a plate, in which it is determined whether or not heat has been applied to a non-image portion of a line in front of a non-image portion of interest. The application time of the heat to the noted non-image portion is reduced, and further, it is determined whether or not the non-image portion of the line next to the noted non-image portion is scheduled to be applied. Is higher than the Further shortening the application time of heat to non-image areas that, when the non-image areas of the previous line is not already applying heat,
A determination is made as to whether or not heat is to be applied to both non-image portions adjacent to the noted non-image portion, and if both are applied to at least one of the non-image portions as a result of the determination, a case where both are not applied A plate making method characterized by further shortening the time for applying heat to the noted non-image area. 7. A heating element of a thermal head which is arranged or moved in a main scanning direction relative to a microporous plastic sheet is moved in a sub-scanning direction, and a surface or an inside of a non-image portion of a desired print image is formed. A stencil plate making a negative image by applying heat necessary for melting until the heat is applied, and closing the micropores of the microporous plastic sheet where the heat is applied by heat shrinkage or heat melting to form an ink non-leaching portion. A control program for controlling the apparatus, wherein it is determined whether or not heat has been applied to the non-image portion of the line before the target non-image portion. The application time of heat to the noted non-image portion is shorter than that of the noted non-image portion, and further, it is determined whether or not the non-image portion of the line next to the noted non-image portion is to be applied, and as a result of the determination, the application is not scheduled In case Control program and controls the application timing of the heating element so as to further shorten the application time of heat to non-image areas to the attention than if. 8. A heating element of a thermal head which is arranged or moved in a main scanning direction relative to a microporous plastic sheet is moved in a sub-scanning direction, and a surface or an inside of a non-image portion of a desired print image is formed. Stencil plate making a non-ink portion by applying heat necessary for melting to a negative image shape, and closing the micropores of the microporous plastic sheet in the portion to which the heat is applied by heat shrinkage or heat melting. A control program for controlling the apparatus, wherein it is determined whether or not heat is to be applied to a non-image area on both sides of a non-image area of interest, and the determination result is applied to at least one of the non-image areas. In this case, a control program is characterized in that the application timing of the heating element is controlled so that the time of applying heat to the noted non-image area is shorter than when both are not applied. 9. A heating element of a thermal head which is arranged or moved in a main scanning direction relative to a microporous plastic sheet is moved in a sub-scanning direction, and a surface or an inner portion is formed in a non-image area of a desired print image. A stencil plate making a negative image by applying heat necessary for melting until the heat is applied, and closing the micropores of the microporous plastic sheet where the heat is applied by heat shrinkage or heat melting to form an ink non-leaching portion. A control program for controlling the apparatus, wherein it is determined whether or not heat has been applied to the non-image portion of the line before the target non-image portion. The application time of heat to the noted non-image portion is shorter than that of the noted non-image portion, and further, it is determined whether or not the non-image portion of the line next to the noted non-image portion is to be applied, and as a result of the determination, the application is not scheduled In case Further shortening the application time of heat to non-image areas to the attention than if, when the non-image areas of the previous line is not already applying heat,
A determination is made as to whether or not heat is to be applied to both non-image portions adjacent to the noted non-image portion, and if both are applied to at least one of the non-image portions as a result of the determination, a case where both are not applied A control program for controlling the application timing of the heating element so as to further shorten the application time of the heat to the noted non-image area.