JPH08132584A - Thermosensitive stencil printing device - Google Patents

Abstract

PURPOSE: To obtain a thermal head of which pierced holes are made fine to be respectively independently pierced by a method wherein life of the thermal head is prolonged by making a grazed layer have a specific thickness. CONSTITUTION: A thermal head is formed by laminating in order a resistor layer 7, an electrode 6, and a protective film 5 on a grazed layer 8 provided on an upper surface of a base 9. Then, when voltage is applied between the electrodes 6 via the protective film 5, an electric current flows to the resistor layer 7, i.e., a heating element part 10, a thermosensitive stencil master is melted to be pierced, and a hole-pierced pattern is formed on the thermosensitive stencil master. In that case a thickness of the glazed layer is at most 60μm. A structure of the glazed layer is a whole glazed type or a partial glazed type. Consequently a diameter of the pierced hole of the thermosensitive stencil master which is melted, pierced, and processed can be lessened. Further, since accumulation of heat can be suppressed to a moderate extent, thermal stress or the like applied to the heating element part in continuous printing is decreased, a life of the heating element is improved, and besides the diameter of the pierced hole is not too much increased.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A thermal head having a glaze layer is brought into contact with a heat-sensitive stencil master having at least a thermoplastic resin film, and a minute heating element portion of the thermal head is caused to generate heat in accordance with an image signal to form the thermoplastic resin film. The heat-sensitive stencil master is wound around the outer peripheral surface of the printing drum, and ink is supplied from the inner peripheral side of the printing drum to obtain the perforation pattern according to the image signal. A well-known stencil printing machine is known in which an ink image corresponding to the image signal is formed on a printing paper by the ink bleeding through to obtain a desired printed matter.

A so-called thin-film type thermal head is often used as a thermal head, and its general structure will be described. 9 shows the shape of the heating element of the thermal head, and FIG. 10 shows the sectional structure of the thermal head. 9A shows a rectangular type, and FIG. 9B shows a heat concentration type. In FIGS. 9A and 9B, reference numeral 91
Is a thermal head, reference numeral 10 is a heating element portion, reference numeral 6 is an electrode, reference numeral 15 is a heat concentrating portion where heat is concentrated, reference numeral S is a main scanning direction, and reference numeral F is a sub-scanning direction orthogonal to the main scanning direction S. Shown respectively.

The thermal head 91 is roughly classified into two types according to the glaze structure. One of them is shown in FIG.
As shown in (a), the entire surface is a glaze layer in which the glaze layer 8 is entirely on the upper surface of the base material 9, and the other is shown in FIG.
As shown in (b), it is a partial glaze type in which the glaze layer 8 is partially present on the upper surface of the base material 9 and below the heating element section 10. In both cases, the resistor layer 7, the electrode 6, and the protective film 5 are laminated in this order on the glaze layer 8. The base material 9 is alumina or the like, the glaze layer 8 is electrically or thermally insulating glass or the like, and the resistor layer 7 is a high electrical resistance material such as tantalum silicon (TaSi) or tantalum nitride (Ta ₂ N). Are formed of a metal material such as aluminum. Further, the protective film 5 is an electrode due to abrasion caused by contact between an oxidation resistant layer formed of silicon dioxide (SiO ₂ ) or the like formed under the protective film 5 and a thermoplastic resin film or the like formed over the oxidation resistant layer. 6 and a wear resistant layer such as tantalum pentoxide (Ta ₂ O ₅ ) for protecting the resistor layer 7.

The thermal head 91 has a large number of minute heating elements 10 arranged in the main scanning direction S at a constant pitch in proximity to each other. A heat-sensitive stencil master (not shown) is shown in FIG. 9 (a) and 9 (b), while being conveyed in the master conveyance direction, that is, in the sub-scanning direction F, the heating element portion 10 is directly contacted via the protective film 5. When a voltage is applied between the electrodes 6 in this state, a current flows through the resistor layer 7 between the electrodes 6, that is, the heating element portion 10, and the heating element portion 10 generates heat due to Joule heat, so that the protective film 5 is removed. The heat-sensitive stencil master, which is in direct contact with the heating element portion 10 via the heat-stencil master, is melt-punched, and a punching pattern is formed in the heat-sensitive stencil master.

In such a stencil printing apparatus, a perforated image suitable for the resolution of the thermal head is formed on the thermosensitive stencil master, and a printed image (ink image) faithful to any original image is thermosensitive. Reproduced in the stencil master,
At the same time, in order to prevent the set-off phenomenon that occurs on the back side of the printing paper, the diameter of each hole of the heat-sensitive stencil master's melt-punched pattern is made finer, and the amount of ink transferred to the printing paper is made independent. Must be reduced. In order to solve such a problem, for example, as disclosed in Japanese Patent Laid-Open No. 4-265759, regarding the size of the heating element of the thermal head, the main scanning pitch of the length in the main scanning direction (adjacent in the main scanning direction). The pitch between the heating element portions) and the ratio of the length in the sub-scanning direction to the sub-scanning pitch (the pitch between adjacent heating element portions in the sub-scanning direction) have been proposed. The "set-off phenomenon" refers to a phenomenon in which when the printed matter is immediately overlaid on the discharge tray or the like, the ink on the ink image side of the printed matter below the printed matter is transferred to the back side of the printed matter.

[0007]

However, since the diameter of the perforation obviously depends on the size of the heating element, when the diameter of the perforation is to be reduced, the size of the heating element of the thermal head is the main length in the main scanning direction. In the above-mentioned technique of defining the scanning pitch and the ratio of the length in the sub-scanning direction to the sub-scanning pitch, it is necessary to reduce the ratio and miniaturize the size of the heating element of the thermal head. Therefore, as a side effect, when trying to obtain the same peak temperature in the heating element part of the thermal head, the smaller the heating element part of the thermal head becomes, the smaller the heating element unit becomes due to the escape of heat to the electrodes of the thermal head. The required energy per area becomes large, and as a result, the life of the heating element of the thermal head becomes shorter as the dimension of the heating element becomes smaller.

In a thermal head in which the thickness tg of the glaze layer 8 provided on the heating element section 10 exceeds 60 μm, the heat accumulation effect during continuous printing is greater, so the peak temperature of the heating element section 10 is The temperature becomes considerably higher than the peak temperature when heat is not stored, the applied energy per unit area of the heating element part 10 tends to be over, thermal stress is applied, and oxidation of the heating element part 10 is promoted, so that the electrical resistance value is increased. Since the change easily occurs, there is a problem that the life of the heating element portion 10 of the thermal head 91 is shortened.

Further, there is also a problem that in the heat-sensitive stencil master which has been perforated and plate-prepared, an independently perforated plate cannot be obtained.

Further, the plate making time of the stencil printing apparatus (also called the heat generation operation time interval of the heating element of the thermal head, the printing cycle or the line cycle) is, for example, 2.5 msec / l.
In recent years, speeding up plate making time such as ine or less has further increased the heat storage effect of the thermal head, and the power-resistant life of the thermal head has also been shortened accordingly. It has become very difficult to obtain independently perforated stencil masters.

Therefore, in order to solve such a problem, the present invention can achieve a long life of the heating element portion of the thermal head without making the dimension of the heating element portion of the thermal head too small, and melting The heat-sensitive stencil master that has been perforated and plate-made has a fine perforation size, and each of the perforations is independent of each other, forming a suitable perforation image according to the resolution in the main scanning direction and the sub-scanning direction. As a result, it is possible to form a printed image that is faithful to any original image, and at the same time, it is possible to prevent the occurrence of set-off defects, and at the same time, speed up plate making (printing cycle: 2.5 m, for example).
It is also an object of the present invention to provide a heat-sensitive stencil printing apparatus capable of obtaining the above-mentioned objects in terms of sec / line or less).

[0012]

According to the present invention, a thermal head having a glaze layer is brought into contact with a heat-sensitive stencil master having at least a thermoplastic resin film, and a minute heating element portion of the thermal head is set in accordance with an image signal. Heat is generated to melt and punch the thermoplastic resin film in a position-selective manner to obtain a punching pattern according to the image signal, and this heat-sensitive stencil master is wound around the outer peripheral surface of the printing drum, and ink is applied from the inner peripheral side of the printing drum. Is a heat-sensitive stencil printer that forms an ink image corresponding to an image signal on a printing paper by the ink bleeding through a perforation pattern, wherein the glaze layer has a thickness of
The thickness is 60 μm or less (the invention according to claim 1).

The lower limit is taken into consideration from the viewpoint of ensuring the smoothness of the base material forming the resistor layer through the glaze layer and the difficulty in the current technical level of production, and the heat-sensitive stencil during continuous printing. Since the experimental results were obtained in which the respective holes formed in the master were independently separated, considering the upper limit thereof, it is particularly preferable that the thickness of the glaze layer is in the range of 5 to 50 μm. The structure of the glaze layer may be a full-glaze type (see FIG. 10A) or a partial glaze type (see FIG. 10B).

Further, in the heat-sensitive stencil printing apparatus according to the first aspect, the thermal head temperature detecting means for detecting the temperature of the thermal head and the perforation energy supplied to each heating element of the thermal head are supplied to the thermal head temperature. A perforation energy adjusting means for adjusting the energy to a predetermined energy according to the temperature of the thermal head detected by the detecting means can be provided (the invention according to claim 2).

A specific example of the thermal head temperature detecting means is a thermistor. It is desirable that the temperature of the thermal head be detected at the surface portion of the heating element, for example, at a portion near the surface of the center of the heating element surrounded by the electrodes. Therefore, the temperature of the thermal head main body is detected on the thermal head substrate, which is the circuit substrate on which the thermal head is mounted (see FIG. 3).

As the drilling energy adjusting means, specifically, a microcomputer, a microprocessor or the like can be used.

Further, in the heat-sensitive stencil printing apparatus according to the first or second aspect, the size of the heating element portion of the thermal head in the main scanning direction is 30 to 95% of the pitch between adjacent heating element portions in the main scanning direction. And the dimension of the heating element portion in the sub-scanning direction is set in the range of 30 to 95% of the pitch between adjacent heating element portions (the invention according to claim 3).

Further, in the heat-sensitive stencil printing apparatus according to the present invention, the thermal history control means for controlling the thermal history of each heating element of the thermal head, and the thermal head control means by the thermal history control means. When each heating element part is driven with thermal history control, at least the second pulse for thermal history control has an applied energy of 40 to 95% of the first pulse, and each heating element part of the thermal head. Energy adjusting means for controlling the individual heating elements of the thermal head can be provided (the invention according to claim 4).

As the heat history control means, for example, Japanese Patent Laid-Open No.
The recording pulse control method described in JP-A-7-80078 can be used. This recording pulse control method is applied to the first recording pulse generating circuit and the second recording pulse generating circuit in the thermal recording device.
Recording pulse generating circuit, an N-bit serial-parallel conversion circuit, and a circuit for comparing the recording data of the main row for executing recording with the recording data of the previous row for which recording has already been executed. After converting the N-bit recording data from the serial information to the parallel information by the parallel conversion circuit, the recording data of the main row is black writing information,
When the recording data of the preceding row is black writing information, the recording pulse transmitted from the first recording pulse generating circuit is applied to the heating resistor of the thermal recording apparatus, and the recording data of the main row is further applied. Is black writing information and the recording data of the preceding row is white writing information, the recording pulse transmitted from the second recording pulse generating circuit is applied to the heating resistor.
Further, when the recording data of the main line is white writing information, the recording pulse is not applied to the heating resistor.

As the energy adjusting means, specifically, a microcomputer, a microprocessor or the like can be used.

In the heat-sensitive stencil printing apparatus according to any one of claims 2 to 5, the perforation energy adjusted to a predetermined energy is supplied by changing the energizing pulse width to the heating element of the thermal head. It may be performed, or may be performed by changing the value of the current flowing through each heating element or the value of the voltage applied to the heating element according to the image signal.

Further, the minute heating elements arranged in the main scanning direction in the thermal head may be so-called rectangular type or heat concentration type.

As the heat-sensitive stencil master used in the heat-sensitive stencil printing apparatus according to any one of claims 2 to 4, a thermoplastic resin on a porous support such as conventionally known Japanese paper is used. It is possible to use an integrated film formed by stacking films, or it is possible to use a heat-sensitive stencil master "consisting essentially of a thermoplastic resin film".
Therefore, the heat-sensitive stencil master has at least the thermoplastic resin film.

In the invention as defined in claim 5, the thermosensitive stencil master "consisting essentially of a thermoplastic resin film" includes not only a thermoplastic resin film but also an antistatic agent on the thermoplastic resin film. Those containing trace amounts of such components, and further, one or more thin film layers such as an overcoat layer formed on both main surfaces of the thermoplastic resin film, that is, at least one of the front surface and the back surface. Including.

[0025]

The operation of the present invention will be described with reference to FIGS. First, the content of the thickness tg of the glaze layer 8 on various characteristics of the thermal head will be described with reference to FIGS. 4 and 8. FIG. 4A shows characteristics relating to the peak temperature of the thermal head and the number of applied pulses when the thickness tg of the glaze layer 8 of the thermal head is used as a parameter. From the characteristic diagram, it can be seen that the heat storage in the thermal head increases as the number of applied pulses increases, and that the peak temperature of the thermal head hardly changes when applied up to a certain number of pulses, so that the heat storage is saturated.
Further, it is shown that the heat storage becomes smaller as the thickness tg of the glaze layer 8 is smaller (thinner), and the heat storage becomes larger as the thickness tg of the glaze layer 8 is larger (thicker). FIG.
(B) represents the characteristics relating to the peak temperature of the thermal head and the printing cycle when the thickness tg of the glaze layer 8 of the thermal head is used as a parameter. This characteristic is when the number of applied pulses is the 200th pulse,
From the characteristic diagram, it is shown that the shorter the printing cycle is, the larger the heat storage is, and the smaller the thickness tg of the glaze layer 8 is, the smaller the heat storage is.

Therefore, from FIGS. 4 (a) and 4 (b), it is understood that the heat accumulation becomes smaller as the thickness tg of the glaze layer 8 becomes smaller, when the number of applied pulses and the printing cycle are taken into consideration.

Next, the content of the thickness tg of the glaze layer 8 on the surface temperature distribution of the heating element of the thermal head will be described with reference to FIG. In FIG. 5A, the heating elements 10 of the thermal head are sandwiched by a pair of electrodes 6 and arranged in a line in the main scanning direction S at a pitch p10 between adjacent heating elements in the main scanning direction S. The dimension S10 of the heating element portion 10 in the main scanning direction S and the dimension F10 of the heating element portion 10 in the sub-scanning direction F are set to predetermined dimensions. FIG. 5B shows the surface temperature distribution of the heating element portion 10 in the main scanning direction S of the thermal head with the thickness tg of the glaze layer 8 of the thermal head as a parameter, and FIG. 5C shows the thermal head. The surface temperature distribution of the heating element portion 10 in the sub-scanning direction F of the thermal head is shown with the thickness tg of the glaze layer 8 as a parameter. Further, FIG. 5D shows that the thermoplastic resin film of the heat-sensitive stencil master 61 used in the heat-sensitive stencil printing apparatus formed on the surface temperature distribution curve of the thermal head in FIG. Thermosensitive stencil master 61 at a certain temperature, that is, "threshold temperature" A ° C
7 shows a punching state of the punching pattern of FIG. From FIG. 5D, the difference in the spread of the surface temperature of the heating element part 10 in the main scanning direction S becomes large depending on the size of the thickness tg of the glaze layer 8, and the perforation h of the heat-sensitive stencil master 61 that is melted and perforated. Differences also occur in size, and in the case where the glaze layer 8 has a large thickness tg, for example, 65 μm, adjacent holes are connected to each other, and independent hole pattern h cannot be obtained. 5 (a), (b), (c), (d)
Easily, under the condition that the energy for perforation supplied to the individual heating elements 10 of the thermal head is the same, the smaller the thickness tg of the glaze layer 8 is, the more perforated the heat-sensitive stencil master 61 is perforated. It can be seen that the pattern perforations h can be made finer. In addition, FIG.
In (c), the peak temperature of the heating element portion 10 of the thermal head during continuous printing is the thickness tg of the glaze layer 8.
4A, a difference occurs as described with reference to FIG. 4A, and the larger the thickness tg of the glaze layer 8, the higher the thickness. FIG. 4
The same can be said when the printing cycle is made faster (shorter) as described in (b), and the temperature rise due to the heat storage action causes an over temperature (over power) to the heating element portion 10 of the thermal head. This is a cause of shortening the life of the heating element section 10.

6 (a1), (a2), and (a3) show the case where the thickness tg of the glaze layer 8 is large, and FIGS. 6 (b1), (b2), and (b3) show the thickness of the glaze layer 8. When the length tg is small, when the first pulse is applied and when 2
The relationship between the surface temperature distribution of the heating element portion 10 in the main scanning direction S of the thermal head after the application of 00 pulses and the punching state is shown. As can be seen from the surface temperature distribution of each of the heating elements 10, the thickness t of the glaze layer 8
Depending on the size of g, the difference in the spread of the surface temperature of the heating element portion 10 in the main scanning direction S also becomes large, and the size of the perforation h melt-perforated in the heat-sensitive stencil master 61 also becomes different.
If the thickness tg of the glaze layer 8 is large, 20
In the worst case after application of 0 pulse, adjacent holes are connected to each other, and it becomes impossible to obtain holes h having an independent hole pattern. This can be said at the same time in the sub-scanning direction F.

In the heat-sensitive stencil printing apparatus, the print image (ink image) is formed by the ink that oozes from the perforation pattern of the heat-sensitive stencil master 61, and the stencil is transferred depending on the amount of the transferred ink to the printing paper. It affects the stain called set-off phenomenon peculiar to the printing device, and the stain becomes more severe as the amount of ink transfer increases. Therefore, the perforation phenomenon of the perforation pattern cannot be suppressed unless the perforations h of the perforation pattern are independent and the amount of ink transfer to the printing paper is controlled. Therefore, the perforation h of the perforation pattern is independent, and the smaller the size thereof, the more the set-off phenomenon disappears. In a facsimile or the like using a thermal head, the glaze layer 8 is used as a heat insulating layer in order to prevent heat generated in the heating element of the thermal head from escaping in a usage method contrary to the present invention. The thickness is increased to about 65 μm. Conversely, the heat storage effect of the glaze layer 8 is utilized to some extent. For this reason, it is preferable to connect adjacent heating dot patterns to increase the solid density and obtain a desirable print product.Unlike a facsimile using a thermal head, etc., in a heat-sensitive stencil printer, as described above. The perforation h of the perforation pattern of the heat-sensitive stencil master 61 is not independent, and if they are connected, the amount of ink transfer increases and the set-off phenomenon deteriorates. Is preferable to be finer and independent, whereas thinning of the glaze layer 8 is very effective.

As described above, according to the first aspect of the present invention, the thickness of the glaze layer is reduced to 60 μm or less, thereby reducing the perforation diameter of the heat-sensitive stencil master that has been melt perforated and plate-made. be able to. Further, since the above heat storage is suppressed appropriately, the thermal stress applied to the heating element portion of the thermal head during continuous printing is reduced, the life of the heating element portion is improved, and the perforation diameter is not too large.

Next, the operation of the invention according to claim 2 will be described. Heat-sensitive stencil master 61 that has been melt-punched and plate-made
The amount of ink that oozes out from the heat sensitive stencil master is proportional to the opening area of each minute perforation that constitutes the perforation pattern, that is, the size of the perforation. It depends on the magnitude of the perforation energy supplied to each of the heating elements. Therefore, the size of the perforation as one unit of the perforation pattern formed on the heat-sensitive stencil master 61 is controlled.

Further, as shown in FIG. 7, when the perforation energy supplied to the individual heating elements of the thermal head is the same applied energy, the peak temperature of the heating elements of the thermal head is The higher the thermal head temperature detected by the head temperature detecting means, the higher the temperature. For example, in FIG. 7A1, the thermal head temperature T ₁
Under the condition that the applied energy having the energizing pulse width t ₁ (t ₁ > t ₂ ) is supplied to the heating element of the thermal head and the same applied energy under the condition that the temperature is raised to the thermal head temperature T ₂ ( Comparing the case where the energizing pulse width t ₁ ) is supplied to the heating element portion of the thermal head, the peak temperature of the heating element portion of the thermal head is the thermal head temperature T ₂
Under the condition of, the heat-sensitive stencil master 6
The size of the perforation h formed in Fig. 1, that is, Fig. 7 (b2).
It can be seen that the perforation h shown in Fig. 7 is larger than that in Fig. 7 (b1). Therefore, in such a case,
As shown in FIG. 7A2, the energization pulse width t is shorter than the energization pulse width t ₁ under the condition of the thermal head temperature T _2.
By controlling the thermal head so that the applied energy of ₂ (t ₁ > t ₂ ) is supplied to the heating element portion of the thermal head, the size of the perforation h can be adjusted to an appropriate value similar to that shown in FIG. 7 (b1). The size of the perforation h is set (Fig. 7 (b)).
See 3)).

That is, most of the heat generated in the heating element portion of the thermal head is consumed by the melt perforation of the heat-sensitive stencil master 61, but a part of the generated heat is also transferred to the thermal head main body and the thermal head is thermally transferred. Increase the temperature of the head body. The above-mentioned temperature rise of the thermal head main body is generally not so large, but when the thermal head is continuously operated for a long time, some temperature rise is inevitable. In such a case, the heat generated by the thermal energy of the thermal head body is added to the heat generated by the energy for perforation to form a perforation larger than the size of the perforation corresponding to the image density of the printed image. The higher the thermal head temperature is, the larger the size becomes, and the desired perforation cannot be obtained. Therefore, when the influence of the temperature rise of the thermal head on the image density is regarded as important, it is necessary to automatically compensate for it. Therefore, in order to obtain the optimum perforation diameter regardless of the thermal head temperature, the thermal head temperature detecting means detects the thermal head temperature, shortens the energizing pulse width when the thermal head temperature is high, and lengthens it when the temperature is low. The thermal head may be controlled so that it is energized. As a result, the peak temperature of the heating element portion of the thermal head becomes constant regardless of the temperature of the thermal head, and the hole diameter becomes constant. Therefore, the size of the perforation pattern is determined according to the temperature of the thermal head, while the size of the perforation is determined by the energy for perforation. There exists a correspondence with and this correspondence can be determined experimentally.

As described above, according to the second aspect of the invention, the energy for punching supplied to each heating element of the thermal head is detected by the thermal head temperature detecting means by the punching energy adjusting means. According to the temperature of the thermal head, it is possible to form a suitable perforated image according to the resolution in the main scanning direction and the sub-scanning direction to form a printed image that is faithful to any original image, and at the same time set off. The energy is corrected and adjusted to a predetermined energy that can prevent the occurrence of defects.

According to the third aspect of the present invention, each of the functions of the first or second aspect of the invention can be obtained by the above configuration without forcibly reducing the size of the heating element portion of the thermal head.

According to the fourth aspect of the invention, the heat history control means for controlling the heat history of the individual heating elements of the thermal head drives the individual heating elements of the thermal head together with the heat history control. At this time, the energy adjusting means supplies at least the second pulse for controlling the thermal history to each heating element of the thermal head with the applied energy of 40 to 95% of the first pulse. The individual heating element parts of are controlled.

In the invention of claim 5, a heat-sensitive stencil master consisting essentially of a thermoplastic resin film, that is, a heat-sensitive stencil master without a porous support, has been developed in recent years to improve image quality. It is what Since such a heat-sensitive stencil master does not have a support of a thermoplastic resin film, in order to secure the printing durability of the heat-sensitive stencil master, the perforation pattern formed on the heat-sensitive stencil master melt-punched and plate-made Miniaturization and independence of each perforation are essential, and it is important to reduce the thickness of the glaze layer of the thermal head even when using a heat-sensitive stencil master consisting essentially of a thermoplastic resin film. Works very effectively.

[0038]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a heat-sensitive stencil printing machine which is an embodiment of the present invention. First, the overall configuration of the heat-sensitive stencil printing apparatus and the stencil printing process will be briefly described with reference to FIG.

In the figure, reference numeral 50 indicates an apparatus main body cabinet. The upper portion of the apparatus main body cabinet 50 has a portion indicated by reference numeral 80 which constitutes a document reading portion, the portion indicated by reference numeral 90 therebelow is a plate making plate feeding portion, and the portion indicated by reference numeral 100 on the left side thereof is a porous printing drum. A print drum unit 101 is disposed, a portion 70 on the left side thereof is a plate discharge unit, a portion 110 below the plate making and feeding unit 90 is a paper feed unit, and a portion 120 below the print drum 101 is a portion. Is a printing pressure portion, reference numeral 1 at the lower left of the apparatus main body cabinet 50.
The portions indicated by 30 indicate the paper discharge portions, respectively.

Next, the operation of the heat-sensitive stencil printing apparatus will be described below, including the detailed configuration thereof.

First, a document 60 having an image to be printed is set on a document receiving stand (not shown) arranged above the document reading section 80, and a plate-making start key (not shown) is turned on. To be executed. That is, the print drum 101 of the print drum unit 100 rotates in the direction opposite to the arrow A in the figure, and the rear end of the used heat-sensitive stencil master 61b mounted on the outer peripheral surface of the print drum 101 is the plate discharge unit 70. When approaching the peeling roller pair 71a, 71b, the roller pair 71a, 71b rotates and one of the plate ejection peeling rollers 71 is rotated.
At b, the rear end portion of the used heat-sensitive stencil master 61b is scooped up, and the plate discharge roller pair 73a, 73b and the plate discharge roller pair 71 arranged to the left of the plate discharge roller pair 71a, 71b.
a plate discharge conveyor belt pair 72 hung between a and 71b
The used heat-sensitive stencil master 61b is gradually peeled from the outer peripheral surface of the printing drum 101 by the plate discharge peeling / conveying unit composed of a and 72b, and is discharged into the plate discharging box 74 while being conveyed in the direction of the arrow Y1. finish. At this time, the print drum 101 continues to rotate in the counterclockwise direction. The discharged used heat-sensitive stencil master 61b is then compressed inside the plate discharge box 74 by the compression plate 75.

In parallel with the plate discharging process, the document reading section 80 reads the document. That is, the document 60 set on the document receiving table has a separation roller 81, a pair of front document conveying rollers 82a and 82b, and a pair of rear document conveying rollers 83a and 8a.
Each rotation of 3b is carried in the direction of the arrow Y2 to Y3 and is used for exposure reading. At this time, the original 6
When there are a large number of 0's, only the lowermost original is conveyed by the action of the separating blade 84. When reading the image of the original 60, the reflected light from the surface of the original 60 illuminated by the fluorescent lamp 86 is conveyed while being conveyed on the contact glass 85.
The reflection is performed by the mirror 87, and the light is incident on the image sensor 89 including a CCD (photoelectric conversion element) through the lens 88. That is, when reading the original 60,
The document is read by a known “reduced document reading method”, and the document 60 whose image has been read is discharged onto a document tray 80A. The electric signal photoelectrically converted by the image sensor 89 is input to an analog / digital (A / D) conversion board (not shown) in the apparatus main body cabinet 50 and converted into a digital image signal.

On the other hand, in parallel with this image reading operation,
A plate making process and a plate supplying process are performed based on the image information converted into a digital signal. The core tube 61s of the master roll 61R, which is wound around the core tube 61s in a roll shape, is rotatably supported by a rotation support member (not shown) arranged at a predetermined portion of the plate making plate feeding section 90, and is heat-sensitive. The stencil master 61 is pulled out from the master roll 61R and is transported to the downstream side of the master transport path by the rotation of the platen roller 92 and the feed roller pair 93a, 93b which are pressed against the thermal head 91 via the heat-sensitive stencil master 61. It With respect to the heat-sensitive stencil master 61 conveyed in this way, a large number of minute heating elements arranged in a line in the main scanning direction of the thermal head 91 are used for the above A / D conversion substrate and subsequent plate-making control (not shown). The thermoplastic resin film of the heat-sensitive stencil master 61, which is selectively heated in accordance with a digital image signal sent after being subjected to various kinds of processing on the substrate, and which is in contact with the heated heating element, is melt-punched. . In this way, the image information is written as a perforation pattern by the position-selective fusion perforation of the heat-sensitive stencil master 61 according to the image information. The platen roller 92 is also connected to a master feed motor as a driving unit via a timing belt (not shown). The master feed motor is a stepping motor, and is rotated intermittently or continuously. Therefore, the heat-sensitive stencil master 61 is moved by the master feed motor through the platen roller 92 at a predetermined feed pitch in the sub-scanning direction orthogonal to the main scanning direction.

The leading end of the plate-making heat-sensitive stencil master 61a in which the image information is written is sent out toward the outer peripheral side of the printing drum 101 by the plate feeding roller pair 94a, 94b, and is moved downward by a guide member (not shown). And is drooped toward the expanded master clamper 102 (shown in phantom) of the printing drum 101 in the illustrated plate feeding position. At this time, the used heat-sensitive stencil master 61b has already been removed from the printing drum 101 by the plate discharging process.

When the front end of the plate-making heat-sensitive stencil master 61a is clamped by the master clamper 102 at a constant timing, the printing drum 101 is indicated by an arrow A in the figure.
The plate-prepared heat-sensitive stencil master 61a is gradually wound around the outer peripheral surface while rotating in the direction (clockwise direction). The rear end of the plate-made heat-sensitive stencil master 61a is cut into a certain length by the cutter 95 after the plate-making is completed. When the one plate-made heat-sensitive stencil master 61a is completely wound around the outer peripheral surface of the printing drum 101, so-called plate feeding is completed.

The printing process is started at the same time when the plate making and plate feeding are completed. First, the printing paper 6 stacked on the paper feed table 51
The uppermost one of the two is the registration roller pair 113 by the paper feed roller 111 and the separation roller pair 112a and 112b.
a, 113b in the direction of the arrow Y4, and by the registration roller pair 113a, 113b at a predetermined timing synchronized with the rotation of the printing drum 101, the printing unit 1
Sent to 20. Printing paper 62 sent out in this way
However, when it comes between the print drum 101 and the press roller 103, the press roller 103, which has been separated from the lower peripheral surface of the print drum 101, is moved upward to be wound around the outer peripheral surface of the print drum 101. The plate-shaped heat-sensitive stencil master 61a is pressed. Thus, the printing drum 101
The ink oozes from the perforated part of the plate and the perforated pattern part (both not shown) of the plate-making heat-sensitive stencil master 61a, and the bleeding ink is transferred to the surface of the printing paper 62 to form an ink image as a printed image. It is formed.

At this time, on the inner peripheral side of the printing drum 101, from the ink supply pipe 104 to the ink roller 105 and the doctor roller 106, which respectively constitute ink supply means.
Ink is supplied to the ink fountain 107 formed between and, in the same direction as the rotation direction of the printing drum 101, and
Ink is supplied to the inner peripheral side of the print drum 101 by the ink roller 105 that is in contact with the inner peripheral surface while rotating in synchronization with the rotation speed of the print drum 101. The above ink is a W / O type emulsion ink.

The printing paper 62 on which the printing image is formed in the printing unit 120 constitutes the paper discharging unit 130,
Counterclockwise rotation of the transport belt 117, which is peeled off from the print drum 101 by the paper discharge peeling claw 114 and sucked by the suction fan 118, is wound around the suction paper discharge inlet roller 115 and the suction paper discharge outlet roller 116. As a result, the sheet is conveyed in the direction of arrow Y5, drops on the sheet discharge tray 52, and is sequentially discharged and stacked. In this way, so-called test printing is completed.

Next, the number of prints is set with a ten-key pad (not shown), and a print start key (not shown) is turned on. In the same steps as the above-mentioned test printing, the steps of feeding, printing and discharging are repeated by the number of prints set. Then, the stencil printing process is completed.

Next, referring to FIGS. 2 and 3, the thermal head temperature detecting means for detecting the temperature of the thermal head 91 and the individual thermal heads according to the thermal head temperature detected by the thermal head temperature detecting means. Of the perforation energy adjusting means for adjusting the perforation energy to be supplied to the heating element part 10 of the above, and a control process based on these control configurations, and the thickness of the glaze layer of the heating element part 10 of the thermal head 91 of 5 to 5. An example when the thickness is 60 μm will be described.

In FIG. 2, reference numeral 11 indicates a microprocessor as a drilling energy adjusting means. The microprocessor 11 is a CPU (Central Processing Unit), I /
It has a well-known configuration including a 0 (input / output) port, a ROM (read only memory), a RAM (readable / writable memory) and the like. The microprocessor 11 is the thermistor 2
Command signals and data signals are transmitted and received between the thermal head 91 and the thermal head 91 to detect the temperature of the thermal head 91 and control the entire system for adjusting the energy for perforation. A signal related to the thermal head temperature of the thermistor 2 is input to the I / O (input / output) port.

The microprocessor 11 includes the thermistor 2
Has a function of adjusting the energy for perforation according to the temperature of the thermal head detected by. Therefore, in the ROM of the microprocessor 11, a "program relating to energization time for energizing the heating element portion 10 for energy adjustment for perforation according to a change in temperature of the thermal head" is experimentally determined in advance. Remembered

The thermistor 2 has a function as a thermal head temperature detecting means for detecting the temperature of the thermal head 91. As shown in FIG. 3, the thermistor 2 is mounted on the thermal head substrate 1 which is a circuit board on which the thermal head 91 is mounted. It is arranged and detects the temperature of the thermal head 91 main body.
In the figure, reference numeral 3 indicates a heating element housing portion of the thermal head 91, and reference numeral 4 indicates an aluminum heat dissipation support.

In FIG. 2, reference numeral 13 indicates a power source, and this power source 13 is an electric energy corresponding to the punching energy for melting and punching the heat-sensitive stencil master 61 on the thermal head 91 via a thermal head driving circuit (not shown). To supply.

The adjustment of the drilling energy is as described above.
This may be performed by changing the value of the current flowing through each heating element (heating resistor) 10 or the value of the voltage applied to the heating element 10 according to the image signal, but in this embodiment, the thermal head 91 is used. This is performed by changing the pulse width of the energization to each of the heating elements 10. That is, the microprocessor 11 takes in the thermal head temperature data signal output from the thermistor 2 via the I / O (input / output) port. Then, the microprocessor 11 compares the thermal head temperature data signal with the ROM as appropriate, calculates it with the CPU, stores it in the RAM as appropriate, and energizes the heat-sensitive stencil master 61 with an energizing pulse. The width is set to control the thermal head 91. The thermal head 91 receives power supply from the power supply 13 according to the digital image signal, and causes the heating element unit 10 to generate heat according to the energization pulse width set by the microprocessor 11.

FIG. 8 shows another embodiment of the present invention. When the heating element 10 is energized, it is possible to take into consideration the heat history control that is generally performed. For this heat history control,
For example, a thermal history control means (not shown) as a recording pulse control method described in JP-A-57-80078 can be used.

This embodiment is different from the above embodiment in that the heat history control means for controlling the heat history of each heating element portion 10 of the thermal head 91 and the individual heat heads 91 by this heat history control means. When the heating element unit 10 is driven with thermal history control, the second pulse having the second pulse width th for thermal history control is 40 to 95% of the first pulse having the first pulse width tp. A microprocessor 11A (enclosed in parentheses in FIG. 2) as an energy adjusting means for controlling the individual heating elements 10 of the thermal head 91 so as to be supplied to the individual heating elements 10 of the thermal head 91 with the applied energy. And shown).

The microprocessor 11A has the above-described functions added to the functions of the above-described microprocessor 11. For this reason, in addition to the "program relating to the energization time for energizing the heating element portion 10 for adjusting the energy for punching according to the change in the temperature of the thermal head" in the ROM of the microprocessor 11A, "heat history" is further added. The second pulse having the second pulse width th for control is 40 to 95 of the first pulse having the first pulse width tp.
A program relating to the energization time for supplying and energizing the individual heating elements 10 of the thermal head 91 with an applied energy of% "is experimentally determined and stored in advance.

As shown in FIGS. 8 (a) and 8 (b1), when printing is performed on the heating element portion 10 on the line in front of the heating element portion which is about to be printed, the heating element portion that has printed and generated heat is generated. 10
Since the part of the glaze layer 8 under the heat is stored, at this time, the value of the current flowing through the heat generating part 10 or the heat generating part 10
Unless the applied energy is reduced by changing the voltage value applied to the device or by changing the energizing pulse width, the perforation pattern h of the heat-sensitive stencil master 61 becomes large and is connected without being independent. Therefore, when printing is not performed on the previous line and heat is not generated, the first pulse having the applied energy of the first pulse width tp is applied to the thermal head 91.
Is applied to the heat-generating body portion 10 of the heat-sensitive stencil master, and otherwise the above-mentioned phenomenon occurs. Therefore, in order to make the perforation h of the perforation pattern of the heat-sensitive stencil master 61 independent, for example, application of about 70% of the first pulse Important and effective control is performed by applying a second pulse having a second pulse width th having energy to each heating element portion 10 of the thermal head 91 (FIGS. 8A and 8B2). . In addition, in FIG. 8A, a portion related to thermal history control is indicated by a broken line. Further, in this embodiment, the energization pulse width of the second pulse or less is set as the second pulse width th.

The first pulse width tp of the second pulse width th
It is more preferable and effective that the applied energy ratio to is independent of the perforation of the perforation pattern in the heat-sensitive stencil master 61, especially when it is 40 to 95%. The applied energy ratio of the second pulse width th to the first pulse width tp is
If the ratio is less than 40%, the size of the perforated holes h is too small, and the solid filling of the printed image is poor. If the ratio exceeds 95%, the perforated holes h are reversed. Is too large and the transfer amount of the ink to the printing paper increases, which is not preferable from the viewpoint of worsening set-off.

Further, it is more effective to control not only the second pulse width th but also the finer control such as the third and fourth.

The control of the energizing pulse width and the thermal history control in consideration of the automatic compensation due to the change of the thermal head temperature as in the above-mentioned respective embodiments are performed to the main body of the thermal head 91 when the thermal head temperature does not change. When there is no heat storage, that is, when the print cycle is slow, or when image deterioration is acceptable, the glaze layer 8 of the thermal head 91 is used.
Since the independent perforation can be achieved by setting the thickness tg of 5 to 60 μm as described above, the thermistor 2 as the thermal head temperature detecting means and the microprocessor 11 as the perforation energy adjusting means, or the energy adjusting means The configuration of the microprocessor 11A and the like is unnecessary and may be omitted.

Next, the specifications and driving conditions of the thermal head 91 used in each of the above embodiments will be described (see FIGS. 1 to 1).
See the sign of 0).

The thermal head 91 is of a thin film type and a rectangular type, and the type of the glaze layer 8 is a full glaze type. As the glaze material, glass, epoxy resin or the like can be considered, but glass is used here. are doing. The resolution of the thermal head 91 is 400 dpi (dots / inch), the dimension S10 of the heating element portion 10 in the main scanning direction S = 30 μm, the dimension F10 of the heating element portion 10 in the sub-scanning direction F = 40 μm, and the glaze layer 8 Thickness tg = 40 μm, printing cycle is 2.25 msec / lin
When the thermal head temperature is 23 ° C., the energizing pulse width is the first pulse width tp = 468 μsec, the second pulse width th = 395 μsec, and the applied power is 0.11.
It was set to 5 W (watt). As the heat-sensitive stencil master 61, one having a thickness of 40 μm was used, which was obtained by laminating a thermoplastic resin film having a thickness of 2 μm on Japanese paper which is a porous support.

Under such plate-making conditions, when the thermal head 91 is driven to generate heat and the heat-sensitive stencil master 61 is subjected to perforation / plate-making, it is possible to obtain perforations of independent size and to obtain a desired print image. It was possible to obtain a printed material having no offset and a long life of the heating element portion 10 of the thermal head 91. In addition,
For example, the above-described advantages were obtained even under the condition that the printing period was 2.5 ms / line or less and the plate making time was shortened.

However, the thermal head 91 was used in which the thickness tg of the glaze layer 8 was changed to 65 μm, and the other heat-sensitive stencil master 61 was melted and punched under the same conditions as described above. However, independent perforation and perforation with an appropriate size could not be obtained, a desired print image could not be obtained, set-off was considerably bad, and the life of the heating element portion 10 of the thermal head 91 was also long. The thickness of the glaze layer 8 was shorter than that of tg = 40 μm.

On the other hand, the thickness tg of the glaze layer 8 is 60 μm.
However, it was estimated that the above effects were large even if the thickness was less than 5 μm, but it was difficult to meet the current manufacturing technology level. Of the heat sensitive stencil master 61 at the time of continuous printing in consideration of the lower limit of the base material 9 which forms the resistor layer 7 with the interposition of the glaze layer 8 and the smoothness. Considering the upper limit value since the experimental results in which the perforations were independently separated were obtained, it is particularly preferable that the thickness tg of the glaze layer 8 is in the range of 5 to 50 μm.

Further, this heat-sensitive stencil printing apparatus can use a heat-sensitive stencil master consisting essentially of a thermoplastic resin film, for example, the thickness thereof is 2 μm.
When the perforation was performed by changing the energization pulse width to the heating element portion 10 of the thermal head 91 in accordance with the temperature of the thermal head, the thickness of the glaze layer 8 of the thermal head 91 was measured in the same manner as in the above embodiment. When the thickness tg is 40 μm, independent perforations of appropriate size can be obtained, a desired printed image can be formed and a printed material without set-off can be obtained, and the life of the heating element portion 10 of the thermal head 91 can be increased. Could be achieved. In addition, for example, printing cycle: 2.5m
Each of the above advantages was obtained even under the condition that the plate making time was shortened to s / line or less.

However, using the heat-sensitive stencil master of the same thickness consisting essentially of the thermoplastic resin film, and using the glaze layer 8 having a thickness tg of 65 μm, the same applied energy condition (same as , The applied power and energizing pulse width) when the heat-sensitive stencil master is melt perforated / plate-making, independent perforations cannot be obtained, the desired printed image cannot be obtained, and the set-off is considerably bad. The life of the heating element portion 10 of the thermal head 91 was shorter than that of the glaze layer 8 having a thickness tg of 40 μm. Also, when the glaze layer thickness was confirmed to be 60 μm, there were some of the above-mentioned effects, but they were still insufficient.
Although it is presumed that the respective effects are large even if it is less than μm, the particularly preferable range of the thickness tg of the glaze layer 8 is 5 to 50 μm for the reasons described above.

Further, referring to the dimensions of the heating element section 10, from the point of independent perforation of the perforation pattern, the heating element section 10 is described.
The dimension S10 in the main scanning direction S in FIG. 2 is equal to or less than the pitch p10 between adjacent heating element portions in the main scanning direction S (63.5 μm in the above embodiment), and the dimension in the sub scanning direction F in the heating element portion 10 By setting F10 to be equal to or less than the pitch p10 between adjacent heating elements, it is possible to make the perforation pattern of the heat-sensitive stencil master 61 finer and independent.

Further, preferably, the dimension S10 of the heating element portion 10 in the main scanning direction S is set to the pitch p10 between adjacent heating element portions in the main scanning direction S (63.5 in the above embodiment).
μm) and the dimension F10 of the heating element portions 10 in the sub-scanning direction F is 95% or less of the pitch p10 between adjacent heating element portions, the perforation pattern of the heat-sensitive stencil master 61 is reduced. Finer holes and independent holes can be made more effectively. More particularly preferably, the heating element section 1
The dimension S10 in the main scanning direction S at 0 is
30 to 95% of the pitch p10 between adjacent heating elements in
And in the sub-scanning direction F of the heating element portion 10.
The dimension F10 of the
Within the range of from 95% to 95%, it is possible to more effectively miniaturize the perforation pattern of the heat-sensitive stencil master 61 and to make it independent. In this case, the dimension S10 (F in the main scanning direction S (sub-scanning direction F)) of the heating element portion 10 (F
10) is less than 30% of the pitch p10 between adjacent heating elements in the main scanning direction S (sub-scanning direction F), the size of the perforated holes h is too small and the solid image as a printed image is filled. From the point of deterioration, the dimension S10 (F10) of the heating element portion 10 in the main scanning direction S (sub-scanning direction F) is obtained.
However, when it exceeds 95% of the pitch p10 between adjacent heating elements, on the contrary, the size of the perforated holes h is so large that the independent independent perforated h cannot be obtained, and the transfer amount of the ink to the printing paper is not obtained. It is not preferable from the viewpoint that the set-off is worse and the set-off is worse.

The location of the thermistor 2 is not limited to the thermal head substrate 1, but may be provided inside the aluminum heat dissipation support 4.

As the thermal head, in addition to the heating elements arranged in a line in the main scanning direction, the heating elements arranged in a zigzag pattern or in two or more rows in the main scanning direction. You may use the thing.

[0075]

As described above, according to the first aspect of the present invention, due to the above-described structure and operation, the size of the heating element of the thermal head is not significantly reduced, and the heating element of the thermal head to be used is It is possible to achieve a long life, and fine and independent perforations of the heat-sensitive stencil master that has been melt perforated and plate-made can be obtained, and a suitable perforation image can be formed according to the resolution in the main scanning direction and the sub-scanning direction. In addition, it is possible to form a printed image that is faithful to any original image, and at the same time, it is possible to prevent the set-off phenomenon that occurs on the back side of the printing paper. The effect is obtained.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the energy for drilling can be finely adjusted and the main scanning direction and the sub-scanning direction can be achieved. It is possible to form a suitable punched image according to the resolution in the scanning direction to form a printed image that is faithful to any original image, and at the same time, it is possible to prevent the occurrence of set-off defects.

According to the third aspect of the present invention, it is possible to obtain a larger effect than the respective effects of the first or second aspect of the invention without forcibly reducing the size of the heating element of the thermal head.

According to the invention described in claim 4, the above-mentioned constitution and operation can obtain a larger effect than each effect in the invention described in claim 1, 2, or 3.

According to the invention described in claim 5, in addition to the effects of the invention described in claim 1, 2, 3 or 4 due to the above-mentioned constitution and operation, the heat sensitivity substantially consisting of the thermoplastic resin film is obtained. By using the stencil master, it is possible to improve the image quality of a printed image and to secure printing durability, which is a problem peculiar to using the heat-sensitive stencil master.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a heat-sensitive stencil printing apparatus to which an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a control configuration of the heat-sensitive stencil printing apparatus.

FIG. 3 is a side view showing a location of a thermistor that detects the temperature of a thermal head.

FIG. 4 (a) is a characteristic diagram relating to the peak temperature of the thermal head and the number of applied pulses with the thickness of the glaze layer of the thermal head as a parameter, and FIG. 4 (b) shows the glaze layer of the thermal head. FIG. 6 is a characteristic diagram regarding a peak temperature of a thermal head and a printing cycle with a thickness as a parameter.

FIG. 5 (a) is a plan view of the periphery of a heating element portion of the thermal head, and FIG. 5 (b) is a heating element portion in the main scanning direction of the thermal head with the thickness of the glaze layer of the thermal head as a parameter. 5C is a characteristic diagram showing the surface temperature distribution of the heating element portion in the sub-scanning direction of the thermal head with the thickness of the glaze layer of the thermal head as a parameter. (D) is FIG.
It is a top view showing the state of perforation formed in a heat-sensitive stencil master corresponding to A ° C in the characteristic diagram of (b).

6 (a1) and 6 (b1) are plan views of the periphery of a heating element for explaining the size of the glaze layer of the thermal head.
6 (a2) and 6 (b2) are characteristic diagrams showing the surface temperature distribution of the heating element portion in the main scanning direction of the thermal head after the first pulse and 200 pulses applied in FIGS. 6 (a1) and 6 (b1). (A3) and (b3) are shown in FIG.
The first pulse and 200, respectively, formed on the heat-sensitive stencil master corresponding to point C of the characteristic diagram in (b2)
It is a top view showing the state of perforation after pulse application.

7 (a1) and 7 (a2) are characteristic diagrams showing changes in peak temperature of a heating element portion based on a difference in thermal head temperature, and FIGS. 7 (b1), (b2), and (b3) are diagrams. 7 (a
1) and (a2) are plan views showing the state of perforations formed in the heat-sensitive stencil master, respectively.

FIG. 8 (a) is a diagram for explaining the operation with and without thermal history control, and FIGS. 8 (b1) and 8 (b2) show the perforations formed in the heat-sensitive stencil master with and without thermal history control. It is a top view showing a state.

9A and 9B are views showing a shape of a heating element portion of a thermal head, wherein FIG. 9A is a rectangular type and FIG. 9B is a heat concentration type plan view.

10A and 10B are exaggeratedly showing the sectional structure of the thermal head in the vicinity of the glaze layer. FIG. 10A is a sectional view of the entire glaze type, and FIG. 10B is a sectional view of the partial glaze type.

[Explanation of symbols]

2 Thermistor as Thermal Head Temperature Detection Means 8 Glaze Layer 10 Heating Element 11 Microprocessor 11A as Perforation Energy Adjusting Means Microprocessor 61 with Energy Adjusting Means 61 Thermal Sensitive Stencil Master 62 Printing Paper 91 Thermal Head 101 Printing Drum F Sub Scanning direction F10 Dimension in the sub-scanning direction in the heating element portion h Perforation p10 Pitch between adjacent heating element portions in the main scanning direction tg Thickness of glaze layer th Second pulse width tp First pulse width S Main scanning direction S10 Heating element Dimension in the main scanning direction

Claims (5)

[Claims] 1. A thermosensitive stencil master having at least a thermoplastic resin film is brought into contact with a thermal head having a glaze layer, and a minute heating element portion of the thermal head is caused to generate heat in accordance with an image signal to produce the thermoplastic resin. A film is position-selectively melt-punched to obtain a punching pattern according to the image signal, the heat-sensitive stencil master is wound around the outer peripheral surface of the printing drum, and ink is supplied from the inner peripheral side of the printing drum, A heat-sensitive stencil printing apparatus for forming an ink image according to the image signal on a printing paper by the ink bleeding through the perforation pattern, wherein the glaze layer has a thickness of 60 μm or less. Stencil printer. 2. The thermal stencil printing apparatus according to claim 1, wherein the thermal head temperature detecting means for detecting the temperature of the thermal head, and the perforation energy supplied to each heating element of the thermal head are supplied to the thermal head. A heat-sensitive stencil printing apparatus comprising: a perforation energy adjusting unit that adjusts to a predetermined energy according to the thermal head temperature detected by the head temperature detecting unit. 3. The heat-sensitive stencil printing apparatus according to claim 1 or 2, wherein the dimension of the heating elements in the main scanning direction is in the range of 30 to 95% of the pitch between adjacent heating elements in the main scanning direction. And the dimension of the heating element portion in the sub-scanning direction is in the range of 30 to 95% of the pitch between adjacent heating element portions. 4. A thermal stencil printing apparatus according to claim 1, 2 or 3, wherein a thermal history control means for controlling thermal history of each heating element of said thermal head, and said thermal history control means When each heating element of the head is driven with thermal history control, at least the second pulse for thermal history control is 40 to 40 times the first pulse.
A heat-sensitive stencil comprising: an energy adjusting means for controlling each heating element of the thermal head so that the heating element is supplied to each heating element of the thermal head with 95% applied energy. Printing device. 5. The heat-sensitive stencil printing apparatus according to claim 1, 2, 3 or 4, wherein the heat-sensitive stencil master is substantially composed of a thermoplastic resin film.