JPH0867061A - Thermosensitive stencil printing device - Google Patents

Abstract

PURPOSE: To provide a thermosensitive stencil printing device with the perforation of a thermosensitive stencil printing master which is independent without being connected in a main scan and a vertical scanning direction and gives an optimal perforation state to a resolving degree set in the vertical scanning. CONSTITUTION: This thermosensitive stencil printing device consists of a master feed motor 40 which drives a platen roller, a key 10 for setting a resolving degree in the vertical scanning direction, and a microcomputer 20 having the function of a drive control means which controls the master feed motor 40 based on a signal from the key for setting a resolving degree in the vertical scanning direction and the function to adjust an energy for perforation to be supplied to an individual heat generating part of a thermal head 30 to a specified energy level in accordance with a signal from the key 10. The length of the vertical scanning direction of the heat generating part on the thermal head 40 is made shorter than the length of a feed pitch, by a thermosensitive stencil master, which corresponds to a highest resolving degree which can be set by the key 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive stencil printing machine.

[0002]

2. Description of the Related Art A heat-sensitive stencil master on which a perforation pattern corresponding to a printed image is formed is wound around an outer peripheral surface of a printing drum,
A well-known stencil printing machine supplies ink from the inner peripheral side of a printing drum and forms an ink image corresponding to the perforation pattern on a printing paper by the ink bleeding through the perforation pattern. In such a stencil printing machine,
Each heat generating portion arranged in a line in the main scanning direction in the thermal head is energized with a constant line period to convert the electric energy into heat energy, that is, Joule heat is generated to punch the heat-sensitive stencil master. ing. The line cycle means a heating operation time interval when the heating elements of the same heating portion of the thermal head are energized, and is also called a printing cycle.

By the way, when printing is performed in such a stencil printing machine and the printed sheets are sequentially discharged and stacked on the sheet discharge tray, the ink on the surface of the printed sheet that has been discharged first becomes
Next, there occurs a problem called so-called set-off which transfers to the back surface of the discharged printed paper and stains the back surface of the printed paper. Therefore, in order to eliminate such a problem of set-off, for example, JP-A-2-67133, JP-A-4-71847, or JP-A-4-4-2.
As in the technique disclosed in Japanese Patent No. 65759, it has been proposed to suppress the ink transfer amount by independently forming each perforation in the sub-scanning direction.

[0004]

However, although the techniques described in the above publications can solve the problem of set-off, when the resolution in the sub-scanning direction is increased, the perforation of the heat-sensitive stencil master causes the perforation in the sub-scanning direction. Connected to
After all, the resolution of the print image in the sub-scanning direction cannot be increased, and the print image quality has not been sufficient in recent years when higher print image quality is required.

Therefore, according to the present invention, in order to solve such a problem, the perforation of the heat-sensitive stencil master is independent without being connected in the main scanning direction and the sub scanning direction, and corresponds to the set resolution in the sub scanning direction. It is an object of the present invention to provide a heat-sensitive stencil printing apparatus that can obtain an optimum punching state.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 provides at least a thermal head for a thermal head comprising a large number of heating portions arranged in the main scanning direction. While the heat-sensitive stencil master having a plastic resin film is pressed by the platen roller, while moving the heat-sensitive stencil master by the master conveying means in the sub-scanning direction orthogonal to the main scanning direction, in accordance with the image signal, The heat-generating part is caused to generate heat to melt-perforate the thermoplastic resin film in a position-selective manner to obtain a perforation pattern according to the image signal, and the heat-sensitive stencil master is wound around the outer peripheral surface of the printing drum, A stencil printing device which supplies ink from the inner peripheral side of the sheet and forms an ink image corresponding to the image signal on printing paper by the ink bleeding through the perforation pattern. It has a driving means, a sub-scanning direction resolution setting means, a drive control means, and a perforation energy adjusting means, and sets the dimension in the sub-scanning direction in the heat generating portion by the sub-scanning direction resolution setting means. The feature is that it is set to the length of the feed pitch or less corresponding to the highest possible resolution.

The driving means drives the master conveying means so as to move the heat-sensitive stencil master at a predetermined feed pitch. A specific example of the driving unit is a master feed motor connected to the master conveying unit via a rotation transmission member such as a timing belt, and for example, a stepping motor is used. Further, as a specific example of the master conveying means, a pair of master conveying rollers arranged on the downstream side of the platen roller may be used in addition to the platen roller.

The sub-scanning direction resolution setting means is provided for setting the resolution of the ink image as the print image in the sub-scanning direction, and is provided, for example, on the operation panel of the thermal stencil printer. This is a sub-scanning direction resolution setting key for manually inputting the resolution of the ink image in the sub-scanning direction.

The drive control means controls the drive means on the basis of the signal from the sub-scanning direction resolution setting means so as to change the feed pitch corresponding to the set resolution in the sub-scanning direction.

The perforation energy adjusting means adjusts the perforation energy supplied to each heat generating portion of the thermal head to a predetermined energy according to the signal from the sub-scanning direction resolution setting means.

As the drive control means and the perforation energy adjusting means, specifically, a computer or a microprocessor can be used.

Further, the minute heat generating portions arranged in the main scanning direction in the thermal head may be of a so-called rectangular type or a heat concentration type.

In the heat-sensitive stencil printing apparatus according to the first aspect, the perforation energy adjusting means sets the perforation energy to 1
It is possible to adjust so that one image signal is continuously applied a plurality of times (the invention according to claim 2).

In the heat-sensitive stencil printing apparatus according to the first or second aspect of the invention, the energy for perforation supplied to each heat generating portion of the thermal head is adjusted by changing the energizing pulse width to each heat generating portion of the thermal head. Alternatively, it may be performed by changing the value of the current flowing through each heating portion or the voltage value applied to each heating portion according to the image signal.

In the heat-sensitive stencil printing machine according to claim 1, when the energy for perforation is set to be adjusted by changing the energizing pulse width, the resolution in the sub-scanning direction is the resolution in the sub-scanning direction. When the resolution is set to a relatively low resolution among the resolutions that can be set by the setting means, the energization pulse width is set by the drilling energy adjusting means in correspondence with a relatively high resolution for one image signal. The perforation energy can be adjusted such that the energizing pulse having a longer energizing pulse width is applied once (the invention according to claim 3).

According to a fourth aspect of the present invention, in the heat-sensitive stencil printing apparatus according to the first, second or third aspect, the heat-sensitive stencil master is substantially composed of a thermoplastic resin film. That is, as the heat-sensitive stencil master used in the heat-sensitive stencil printing apparatus according to claim 1, 2 or 3, a thermoplastic resin film on a porous flexible support such as conventionally known Japanese paper. It is also possible to use a laminate obtained by stacking and integrating the above, or 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. Here, the heat-sensitive stencil master "consisting essentially of a thermoplastic resin film" includes a thermoplastic resin film alone and a thermoplastic resin film containing a minor component such as an antistatic agent. Further, it includes one or a plurality of 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.

[0017]

According to the invention described in claim 1, when the resolution in the sub-scanning direction is set by the sub-scanning direction resolution setting means, the signal is input to the drive control means, and the drive control means is The thermosensitive stencil master is moved at the feed pitch corresponding to the set resolution in the sub-scanning direction by controlling the driving means to change the feed pitch to correspond to the set resolution in the sub-scanning direction. On the other hand, when the resolution in the sub-scanning direction is set by the sub-scanning direction resolution setting means, the signal is input to the perforation energy adjusting means, and the perforation energy adjusting means responds to the thermal scanning in response to the signal from the sub-scanning direction resolution setting means. By adjusting the perforation energy supplied to each heat generating portion of the head to a predetermined energy, the size of the perforations in the sub-scanning direction of the heat-sensitive stencil master is controlled to an appropriate size, and at the same time, in the heat generating portion. By setting the dimension in the sub-scanning direction to be equal to or less than the length of the feed pitch corresponding to the maximum resolution that can be set by the sub-scanning direction resolution setting means, each perforation can be performed regardless of the set resolution in the sub-scanning direction. Independent perforation optimal for the resolution is performed without being connected to the sub-scanning direction and the main scanning direction.

According to the invention described in claim 2, in addition to the function of the invention described in claim 1, the drilling energy adjusting means includes:
By adjusting the perforation energy so as to be continuously applied to one image signal a plurality of times, the perforation size in the sub-scanning direction of the heat-sensitive stencil master is controlled to a more appropriate size. .

According to the third aspect of the invention, in addition to the operation of the first aspect of the invention, the energy for drilling is adjusted by changing the energizing pulse width. When the resolution in the sub-scanning direction is set to a relatively low resolution among the resolutions that can be set by the sub-scanning direction resolution setting means, the perforation energy adjusting means,
By adjusting the perforation energy so that one energizing pulse having an energizing pulse width longer than the energizing pulse width set for a relatively high resolution is applied once to one image signal, the heat sensitivity is improved. The size of the perforations of the stencil master in the sub-scanning direction is controlled to a more appropriate size.

According to the fourth aspect of the invention, since the heat-sensitive stencil master consisting essentially of the thermoplastic resin film is used, a so-called good fiber-free printed image can be obtained in addition to the above respective functions. To be

[0021]

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

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

Reference numeral 50 indicates an apparatus main body cabinet. Reference numeral 80 on the upper part of the device main body cabinet 50
The portion indicated by means of the numeral forms a document reading section, and the reference numeral 90 below it
A portion indicated by is a plate making plate feeding portion, a portion indicated by reference numeral 100 on the left side thereof is a printing drum portion on which a porous printing drum 101 is arranged, a portion indicated by reference numeral 70 on the left thereof is a plate discharging portion, a plate making plate feeding portion 90 The lower part indicated by reference numeral 110 is a paper feeding portion, the lower part indicated by reference numeral 120 under the printing drum 101 is a printing portion, and the lower left portion indicated by reference numeral 130 in the apparatus main body cabinet 50 is a paper discharge portion. There is.

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

First, a document 60 having an image to be printed is placed on a document placing table (not shown) disposed above the document reading section 80, and a plate making start key (not shown) is pressed.
When the plate making start key is pressed, the plate discharging step is first executed. That is, in this state, the used heat-sensitive stencil master 61b used in the previous printing remains attached to the outer peripheral surface of the printing drum 101 of the printing drum unit 100.

First, the printing drum 101 rotates counterclockwise, and the rear end of the used heat-sensitive stencil master 61b on the outer peripheral surface of the printing drum 101 has a pair of plate discharging and separating rollers 71a, 71.
When the roller pair 71a, 71b is rotated toward the point b, the rear end portion of the used heat-sensitive stencil master 61b is scooped up by one of the plate discharge peeling rollers 71a while rotating, and the plate discharge roller pair 71 is rotated.
a, 71b, a pair of plate discharge rollers 73a, 73 arranged on the left side
b and the plate discharge peeling roller pair 71a, 71b, the plate discharge conveyor belt pair 72a, 72b is conveyed in the direction of arrow Y1 and discharged into the plate discharge box 74, and the used heat-sensitive stencil master 61b is used as a printing drum. The outer peripheral surface of 101 is peeled off, and the plate discharging process is completed. At this time, the print drum 101 continues to rotate in the counterclockwise direction. The used heat-sensitive stencil master 61b that has been peeled off and discharged 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 original 60 placed on the original placing table (not shown) has a separating roller 81, a pair of front original conveying rollers 82a and 82b, and a pair of rear original conveying rollers 83.
The exposure is read while being conveyed in the Y3 direction from the arrow Y2 by each rotation of a and 83b. At this time,
When there are many originals 60, only the lowermost original is conveyed by the action of the separating blade 84. The rear original conveying roller 83a is rotationally driven by the original conveying roller motor 83A, and the front original conveying roller 82a is provided via a timing belt (not shown) stretched between the conveying rollers 83a and 82a. It is driven to rotate and the roller 8
2b and 83b are driven to rotate. The image of the original 60 is read while being conveyed on the contact glass 85.
The reflected light from the surface of the original 60 illuminated by the fluorescent lamp 86 is reflected by the mirror 87, passes through the lens 88, and is CC
This is performed by making the light incident on the image sensor 89 composed of D (charge coupled device) or the like. That is, the reading of the original 60 is performed by a known “reduction type original reading method”, and the original 60 from which the image is read is discharged onto the original 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. That is, the heat-sensitive stencil master 61 set at a predetermined portion of the plate-making plate feeding unit 90 is pulled out from the rolled state and is pressed against the thermal head 30 via the heat-sensitive stencil master 61. A platen roller 92 as a conveying means and a feed roller pair 9
By the rotation of 3a and 93b, it is intermittently transported to the downstream side of the transport path. Heat-sensitive stencil master 6 conveyed in this way
1, a large number of minute heating portions arranged in a line in the main scanning direction of the thermal head 30 selectively generate heat in accordance with the digital image signal sent from the A / D conversion substrate, The thermoplastic resin film of the heat-sensitive stencil master 61 that is in contact with the heat-generating portion that has generated heat 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 leading end of the plate-made heat-sensitive stencil master 61a in which the image information is written is sent toward the outer peripheral side of the printing drum 101 by the plate feeding roller pair 94a and 94b, and is moved downward by a guide member (not shown). To the master clamper 102 (shown in phantom) where the printing drum 101 is in the plate feeding position shown in FIG. 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 rotates in the direction A (clockwise direction) in the drawing and makes a plate on the outer peripheral surface. The heat-sensitive stencil master 61a is gradually wrapped. The plate-shaped heat-sensitive stencil master 61a has a cutter 95 after the plate-making is completed.
Is cut into a certain length by.

When a plate-made heat-sensitive stencil master 61a is wound around the outer peripheral surface of the printing drum 101, the plate-making and plate-supplying steps are finished and the printing step is started. First, the paper feed table 51
The uppermost one of the printing papers 62 stacked on the top is indicated by an arrow Y4 toward the feed roller pair 113a, 113b by the paper feed roller 111 and the separation roller pair 112a, 112b.
Direction, and further, the feed roller pair 113a,
It is sent to the printing unit 120 at a predetermined timing synchronized with the rotation of the print drum 101 by the 113b. The printing paper 62 sent out is printed by the printing drum 101 and the press roller 10.
3, the press roller 103, which has been spaced below the outer peripheral surface of the printing drum 101, is moved upward, so that the plate-made heat-sensitive stencil master 61a wound around the outer peripheral surface of the printing drum 101. Is pressed by. In this way, the perforated portion of the printing drum 101 and the plate-made heat-sensitive stencil master 61
Ink oozes out from the perforation pattern portion of a (both not shown), and the bleeding ink is transferred to the surface of the printing paper 62 to form an ink image as a print image.

At this time, on the inner peripheral side of the printing drum 101, an ink reservoir 107 formed between the ink supply pipe 104 and the ink roller 105 and the doctor roller 106.
The ink is supplied to the inner surface of the print drum 101 while rotating in the same direction as the print drum 101 and in synchronization with the rotation speed of the print drum 101. Supplied to the circumference side. The ink is a W / O type emulsion ink.

The printing paper 62 on which the printing image is formed in the printing unit 120 is peeled off from the printing drum 101 by the paper discharge peeling claw 114, and is sucked by the suction fan 118 while being sucked and discharged by the suction discharge roller 115 and the suction discharge roller 115. By the counterclockwise rotation of the conveyor belt 117 that is stretched around the paper outlet roller 116, the conveyor belt 117 is conveyed toward the paper ejection unit 130 as indicated by arrow Y5, and is sequentially ejected and stacked on the paper ejection tray 52. In this way, so-called test printing is completed.

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

As the heat-sensitive stencil master 61, one having a thickness of 40 μm in which a thermoplastic resin film having a thickness of 1.6 μm is laminated on Japanese paper which is a porous support is used. Next, a configuration for setting the resolution in the sub-scanning direction,
The surroundings of the thermal head 30, the platen roller 92, and control configurations related thereto will be described in detail.

As shown in FIG. 1, a sub-scanning direction resolution setting unit as a sub-scanning direction resolution setting means for setting a resolution in the sub-scanning direction of the ink image is provided on an operation panel (not shown) above the apparatus main body cabinet 50. Key 1
0 is set. This sub-scanning direction resolution setting key 1
0 has a function similar to that of a fine mode setting key in a copying machine or the like, and in order to set the resolution in the sub-scanning direction of the ink image on the printing paper 62, the user manually sets the resolution to the desired resolution. Can be set by inputting to. In the present embodiment, the sub-scanning direction resolution setting key 10 sets the resolution in the sub-scanning direction to 30 by pressing once.
It can be set by switching between two levels of 0 DPI or 400 DPI (dots / inch).

On the operation panel near the sub-scanning direction resolution setting key 10, two LEDs (light emitting diodes) 11 for displaying the resolution setting of 300 DPI and 400 DPI in the sub-scanning direction are arranged in order from the left in the figure. It is arranged.

The platen roller 92 is connected to the master feed motor 40 as a driving means via a timing belt (not shown). The master feed motor 40 is composed of a stepping motor, and is rotationally driven intermittently. Therefore, the heat-sensitive stencil master 61 has the master feed motor 40
Thus, the platen roller 92 is moved in a sub-scanning direction orthogonal to the main scanning direction with a predetermined feed pitch.

The thermal head 30 has a main scanning direction 300.
A so-called rectangular heating element is used for the minute heating portion having a DPI (dot / inch) resolution and arranged in the main scanning direction. Here, in order to explain the content of adjustment of the perforation energy supplied to each heat generating portion of the thermal head 30, first, the detailed configuration of the heat generating portion in the thermal head 30 and its action will be described.

In the stencil printing apparatus, the image density of the printed image is determined by the amount of ink bleeding from the heat-sensitive stencil master 61. The amount of ink that oozes out from the heat-sensitive stencil master 61 is proportional to the opening area of each minute perforation that constitutes the perforation pattern formed in the heat-sensitive stencil master 61, that is, the size of the perforation. Further, the size of the perforations is proportional to the perforation energy corresponding to the temperature of each heat generating portion of the thermal head. Therefore, by adjusting the perforation energy corresponding to the temperature of each heat generating portion of the thermal head, the perforation size of the perforation pattern for obtaining the optimum printed image can be determined.

Next, referring to FIG. 3, a related action between the energy for punching (the temperature of each heating section of the thermal head) supplied to each heating section of the thermal head and the size of the punching of the drilling pattern. Will be described. Well, Figure 3
Referring to (a-3) and (b-3), these drawings are sectional views showing the structure of a minute heat generating portion in the thermal head 30. A portion indicated by reference numeral 1A is a heating element made of a thin layer of a high electric resistance material, a portion indicated by reference numeral 1B is a lead electrode, and a portion indicated by reference numeral 1C is a protective film.

The heating element 1A is a substrate (hatched portion)
Formed on. When a voltage is applied between the lead electrodes 1B, a current flows in the heating element 1A between the lead electrodes 1B, and Joule heat causes the heating element 1A in the energized portion to generate heat. In the thermal head 30, such minute heat generating portions are arranged close to each other at a constant pitch in a direction orthogonal to the paper surface of FIGS. 3A-3 and 3B-3, that is, the main scanning direction. , The heat-sensitive stencil master 61 is shown in FIG.
3) and (b-3) are conveyed in the left-right direction, that is, the sub-scanning direction, and a perforation pattern is formed by melt perforation.

The size of the heating element 1A of the thermal head 30 is 50 in the main scanning direction S as shown in FIG. 3 (b-4).
The size of 40 μm in the sub scanning direction F is used. The dimension of the heating element 1A of the thermal head 30 in the sub-scanning direction F is equal to or less than the length of the feed pitch 63.5 μm / line (line) corresponding to 400 DPI which is the highest resolution that can be set by the sub-scanning direction resolution setting key 10. Is set to.

The heat generating element of the thermal head is of the heat-concentrating type in addition to those described above (the central portion of the heat generating element 1a is formed to have a narrow width, and the current density is increased in this portion to concentrate heat generation in this portion). In this case, in FIG.
As shown in -5), for example, the total length of the heating element portion in the sub-scanning direction F is 50 μm, the length of the heating concentrated portion in the same direction is 10 μm, the entire width of the heating element portion in the main scanning direction S is 50 μm, and the heating concentration in the same direction. Part width is 15μ
The size is m.

When the energy for perforation is supplied to the heat generating portion in the form of electric energy, this energy is generated.
A is converted into heat energy by A, and the temperature of the heat-sensitive stencil master 61 in contact with the protective film 1C rises. The temperature distribution at this time is represented by the curve Tα shown in FIG.
The distribution becomes a mountain shape like the curve Tβ shown in (b-2).
As can be easily understood, FIG. 3 (a-2) shows a case where the perforation energy supplied to the heat generating portion is relatively small, and FIG. 3 (b-2) shows that the perforation energy is relatively large. This is the case.

The straight line indicated by the symbol D in the figure is the "threshold temperature" at which the thermoplastic resin film of the heat-sensitive stencil master 61 is melted and perforated, and the heat-sensitive stencil master 61 is perforated supplied to the heating portion. Fig. 3 (a
-1) Small perforations h as shown in FIG.
Large perforations h as shown in 1) are melt-perforated. In this way, the size of the perforation as one unit of the perforation pattern formed in the heat-sensitive stencil master 61 can be controlled by the perforation energy supplied to each heat generating portion of the thermal head 30, and an appropriate printed image can be obtained. The value of the drilling energy for can be determined experimentally. This situation is
The same applies whether the heat generating portion is rectangular or heat concentrated.

Further, as described above, the adjustment of the energy for punching may be performed by changing the value of the current flowing through each heating portion or the value of the voltage applied to each heating portion according to the image signal. In this embodiment, this is done by changing the width of the energizing pulse to the heating element 1A of the thermal head 30.

Next, with reference to FIG. 2, a description will be given of a control configuration for varying the resolution in the sub-scanning direction, and a configuration for driving and controlling the thermal head 30, the master feed motor 40 and the document feed roller motor 83A.

In the figure, reference numeral 20 indicates a microcomputer. The microcomputer 20, as will be described later, has a thermal head drive circuit 27, a master feed motor drive circuit 41, and a document feed roller motor drive circuit 83.
A command signal and a data signal are transmitted and received between B and the sub-scanning direction resolution setting key 10 to control the entire system of the thermal stencil printing apparatus. The microcomputer 20
It has a CPU (central processing unit), an I / O (input / output) port, a ROM (read-only storage device), a RAM (readable / writable storage device), and the like, and has a well-known configuration connected by a signal bus. Microcomputer 20
As will be described later, the master feed motor 40 changes the feed pitch corresponding to the set resolution in the sub-scanning direction based on the output signal from the sub-scanning direction resolution setting key 10.
Drive control means for controlling the sub-scanning direction resolution setting key 1
Based on the output signal of 0, the second drive control means for controlling the document conveying roller motor 83A so as to change the feed pitch corresponding to the set resolution in the sub scanning direction, and the output of the sub scanning direction resolution setting key 10. It has various functions of perforation energy adjusting means for adjusting the perforation energy supplied to each heat generating portion of the thermal head 30 to a predetermined energy in accordance with the signal.

In the ROM of the microcomputer 20,
Relational data for setting the feed pitch corresponding to the set sub-scanning direction resolution, a program for energy adjustment, and forming a perforation of an optimum size according to the set sub-scanning direction resolution. Relational data of the energizing pulse width corresponding to the energy for drilling for the purpose is experimentally determined in advance and stored.

The sub-scanning direction resolution setting key 10 is connected to the microcomputer 20, and the output of the set sub-scanning direction resolution is displayed on the LED 11 and input to the I / O port of the microcomputer 20. To be done.

In FIG. 2, reference numeral 25 is a decoding circuit, 26 is a power source, 27 is a thermal head drive circuit, 41 is a master feed motor drive circuit, and 83B is a document feed roller motor drive circuit.

The decoding circuit 25 has a function of decoding the image signal digitally encoded by the analog / digital (A / D) conversion board into an image data signal, and outputs the image data signal to the thermal head drive circuit 27. Output.

The master feed motor drive circuit 41 is 1-2
The output of the 1-2 phase excitation circuit for generating the phase excitation pulse is supplied to the master feed motor 40. The master feed motor drive circuit 41 is connected to the master feed motor 40 and drives the master feed motor 40.

Original transport roller motor drive circuit 83B
Has a configuration similar to that of the master feed motor drive circuit 41 and supplies the output of the 1-2 phase excitation circuit for generating the 1-2 phase excitation pulse to the document conveying roller motor 83A.

The thermal head drive circuit 27 receives the image data signal output from the decoding circuit 25, the signal indicating one sub-scan, and the energizing pulse width command and data signal output from the microcomputer 20. It is mainly composed of a drive circuit that outputs a drive signal. The thermal head 30 also includes a shift register that sequentially shifts image data signals for one main scan, and a latch circuit that latches the output of each stage of the shift register.
An AND circuit for driving only the heat generating portion of the thermal head 30 corresponding to the black pixel, a transistor for driving the heat generating portion of the thermal head 30, a diode for preventing reverse current, and the like are provided.

The power supply 26 is a thermal head drive circuit 27.
The thermal head driving circuit 27 supplies electric energy corresponding to the perforation energy for melting and perforating the heat-sensitive stencil master 61 to the individual heat generating portions of the thermal head 30.

Next, an example of changing the resolution in the sub-scanning direction and its operation process will be described with reference to FIGS. 2, 4 to 7, 12 and 13.

First, before the plate-making process is executed by pressing the plate-making start key, the resolution setting key 1 in the sub-scanning direction is set.
Press 0 to set the desired resolution in the sub-scanning direction for the print image. When the resolution setting signal in the sub-scanning direction is output to the microcomputer 20, the microcomputer 20 outputs a signal for setting a predetermined feed pitch corresponding to the resolution in the sub-scanning direction to the master feed motor drive circuit 4.
1 and a signal for controlling the driving of the document conveying roller motor 83A at a predetermined feed pitch corresponding to the resolution in the sub-scanning direction is fed to the document conveying roller motor drive circuit 83.
Send to B. At the same time, the microcomputer 2
0 sends a signal to the thermal head drive circuit 27 to set the energizing pulse width for forming a hole having an optimum size according to the set resolution in the sub-scanning direction. Then, the master feed motor 40 is driven via the master feed motor drive circuit 41 based on the signal of the predetermined feed pitch setting corresponding to the resolution in the sub-scanning direction set by the microcomputer 20, and the master feed motor 40 further drives the platen. The roller 92 is driven to rotate, and the heat-sensitive stencil master 6
1 is conveyed at a predetermined feed pitch and speed.

Further, the document conveying roller motor 83A is driven via the document conveying roller motor driving circuit 83B based on a signal for setting a predetermined feed pitch corresponding to the sub-scanning direction resolution set by the microcomputer 20, Further, the front / rear document transport roller pair 82a, 82b, 83a, 83b is rotationally driven by the document transport roller motor 83A, and the document 60 is transported at a predetermined feed pitch and speed.

In this way, the thermal head drive circuit 27 receives the power supply from the power source 26 to generate an energization pulse (thermal head drive signal) on the basis of the signal for setting the energization pulse width, and the individual heat generation of the thermal head 30. And the heat generating portion corresponding to the black pixel generates Joule heat, and the heat-sensitive stencil master 61 is melt-punched.

Next, when the thermal head 30 having a resolution of 300 DPI in the main scanning direction is used and the resolution in the sub-scanning direction is changed to 300 DPI and 400 DPI, the energizing pulse width setting method and punching of the heat-sensitive stencil master 61 are performed. The relationship with the state will be described with reference to FIGS. 4 to 7, 12 and 13. The thermal head 30
The line cycle Th of is the same in each setting method.

First, a case where the resolution in the sub-scanning direction F is set to 400 DPI in FIGS. 4 and 5 will be described. As shown in FIG. 5, the feed pitch Pf of the heat-sensitive stencil master 61 is 63.5 μm / line corresponding to a resolution of 400 DPI in the sub-scanning direction F. As shown in FIG. 4A, when one energizing pulse corresponding to the energizing pulse width tp1 is applied to the heating element of the thermal head 30,
As for the temperature rising characteristic of the heating element, a substantially sawtooth wave curve is drawn to raise and lower the temperature as shown in FIG. As a result, the perforation state of the heat-sensitive stencil master 61 is, as shown in FIG. 5, a resolution of 400 DPI in the sub-scanning direction F without the perforations h being connected and perforated in the sub-scanning direction F and the main scanning direction S.
A perforation h having an optimum size adapted to

Next, the case where the resolution in the sub-scanning direction F is set to 300 DPI in FIGS. 6 and 7 will be described. As shown in FIG. 7, the feed pitch Pf of the heat-sensitive stencil master 61 is 84.7 μm / line corresponding to a resolution of 300 DPI in the sub-scanning direction F. As shown in FIG. 6A, the heating element of the thermal head 30 is applied with two continuous energizing pulses corresponding to energizing pulse widths tp2 and tp4 for one image signal. When two continuous energizing pulses are applied in this manner, the heating element has a temperature rising characteristic that the temperature is raised and lowered by drawing two continuous sawtooth-shaped curves as shown in FIG. . As a result, in the punching state of the heat-sensitive stencil master 61, as shown in FIG. 7, each punching hole h is largely punched only in the sub-scanning direction F, and further, there is no connection punching in the sub-scanning direction F and the main scanning direction S. , A perforation h having an optimum size adapted to a resolution of 300 DPI in the sub-scanning direction F can be obtained. In addition, by applying two continuous energizing pulses corresponding to energizing pulse widths tp2 and tp4, the peak temperature of the heating element of the thermal head 30 is set to the temperature required for punching the thermosensitive stencil master 61, that is, the thermosensitivity. Since the size of the perforations h in the sub-scanning direction F of the heat-sensitive stencil master 61 can be set to a desired size without making the temperature higher than the threshold temperature of the stencil master 61, the heat generation of the thermal head 30 can be achieved. The heat stress applied to the body can be reduced and reduced. Therefore, according to this example, there is an advantage that the life of the thermal head 30 can be improved. In addition, the code | symbol tp3 is energization pulse width tp2 and tp.
The energization off time during 4 is shown. It should be noted that the size of the perforation h in the main scanning direction S has no effect as much as shown in the figure, and is ignored in the perforated state in FIG. 7 in order to clarify its characteristics.

By the way, in the above example, when the resolution in the sub-scanning direction F is set to 300 DPI, two times corresponding to the energizing pulse widths tp2 and tp4 continuous to the heating element of the thermal head 30 for one image signal. The method of forming the perforation h of the optimum size in the sub-scanning direction F of the heat-sensitive stencil master 61 by applying the energizing pulse has been described, but the life of the heating element of the thermal head 30 due to thermal stress is practically used. In the case of a level where there is no problem, not only the above example but also one energizing pulse width tp5 for one image signal in the heating element of the thermal head 30, as shown in FIG.
The energizing pulse corresponding to the above may be applied to adjust the drilling energy. Here, the energization pulse width tp5 is set to be longer (larger) than the energization pulse width tp1 applied to the heating element of the thermal head 30 when the resolution in the sub-scanning direction F is set to 400 DPI.

In FIG. 12A, the thermal head 3
When the energizing pulse width (energizing time) applied to the heating element of 0 is set to, for example, tp1, the heating temperature of the heating element of the thermal head 30 rises as shown by a part of the broken line in FIG.・ It becomes a cooling curve. Therefore, in the heat-sensitive stencil master 61 at this time, the perforations h ′ having the size shown by the broken line in FIG. 13C are formed. The size of the perforations h ′ formed in the heat-sensitive stencil master 61 in this case is optimum when the resolution in the sub-scanning direction F is set to 400 DPI, but the resolution in the sub-scanning direction F is 30.
It is too small when set to 0 DPI. Therefore, one energizing pulse corresponding to the energizing pulse width tp5 set longer than the energizing pulse width tp1 may be applied to the heating element of the thermal head 30. As a result, the peak temperature of the heating element of the thermal head 30 becomes higher than the peak temperature shown by the broken line in FIG. 12B, as shown by the solid line in FIG. At the same time, as shown in FIGS. 13 (a) and 13 (b).
As shown in FIG. 6B, the temperature distribution at the center point ca (indicated by the alternate long and short dash line in FIG. 7A) in the sub-scanning direction F of the heating element 1A of the thermal head 30 is In the heat-sensitive stencil master 61, the length in the sub-scanning direction F that is equal to or higher than the threshold temperature D becomes longer than when the energizing pulse having the energizing pulse width tp1 is applied (shown by the broken line in FIG. 7B). Accordingly, when the energizing pulse applied to the heating element of the thermal head 30 has the energizing pulse width tp5, the heat-sensitive stencil master 61 is formed with the perforations h having a size as shown in FIG. 13C. This means that when the resolution in the sub-scanning direction F is set to 300 DPI, the perforation h of the optimum size adapted can be obtained. When the energizing pulse applied to the heating element of the thermal head 30 has the energizing pulse width tp5, the thermal head 30
Of the energizing pulse applied to the heating element of the energizing pulse width tp1
Although the size of the perforations h in the main scanning direction S formed in the heat-sensitive stencil master 61 is larger than that in the case where
The extent of the perforation h in the sub-scanning direction F is less affected than the size of the perforation h, and therefore there is no problem in actual use.
Therefore, according to this example, in the case of the above example, that is, when the resolution in the sub-scanning direction F is set to 300 DPI, the thermal head 30 is applied to one image signal.
Two energizing pulse widths tp2 and tp continuous to the heating element of
By applying the energizing pulse corresponding to No. 4, there is an advantage that the control method can be simplified as compared with the method of forming the perforation h of the optimum size in the sub-scanning direction F of the heat-sensitive stencil master 61. .

In consideration of the above matters, Table 1 shows an example of setting the energizing pulse width based on the setting of the resolution in the sub-scanning direction.

[0068]

[Table 1]

As a plate making condition, the thermal head 3 is used.
0 is 300 DPI in the main scanning direction, and 300 DPI and 400 DPI in the resolution in the sub-scanning direction.
Can be selected. The size of the heating element of the thermal head 30 is 50 μm in the main scanning direction and 40 μm in the sub scanning direction, and the line cycle Th thereof is 3 msec / line. The plate making environment was room temperature at 20 ° C. In Table 1, tp1 to tp4 indicate the same energization pulse width (time: μsec) as shown in FIGS. 4 and 6, and tp5 indicates the same energization pulse width (time: μsec) as shown in FIGS. 12 and 13.

As described above, by providing the energizing pulse widths as shown in Table 1, under the same use condition, it is possible to optimize the resolution in the sub-scanning direction without connecting and punching in the main scanning direction S and the sub-scanning direction F. Punches of various sizes were obtained, and the print image quality was optimal.

The size of the heating element of the heating portion of the thermal head in the sub-scanning direction is within a range of 80% or less of the length of the feed pitch corresponding to the highest resolution that can be set by the sub-scanning direction resolution setting means. It is more desirable to do. That is, in the case of the present embodiment, the maximum resolution in the sub-scanning direction that can be set with the sub-scanning direction resolution setting key 10 is 40.
0DPI and the feed pitch is 63.5 μm / li
Since it is ne, the dimension of the heating element in the sub-scanning direction is more preferably 51 μm or less. As a result, even when the resolution in the sub-scanning direction is increased, it is possible to more reliably perform the perforation independently without connecting the perforations in the sub-scanning direction.

The dimension of the heating element of the heating portion of the thermal head in the sub-scanning direction is in the range of 40% or more of the length of the feed pitch corresponding to the highest resolution that can be set by the sub-scanning direction resolution setting means. It is desirable to do. That is, in the case of the present embodiment, the sub-scanning direction resolution setting key 1
The maximum resolution in the sub-scanning direction that can be set at 0 is 400DP
I and the feed pitch is 63.5 μm / line, the dimension in the sub-scanning direction of the heating element is 2
5 μm or more is desirable. In this way, by setting the size in the range of 40% or more of the length of the feed pitch, it is possible to surely punch. This is because if the heat generating element is too small, the heat generation is repeated and the life of the heat generating element is shortened.

As described in the above embodiment, the size of the heating element of the heating portion of the thermal head in the sub-scanning direction corresponds to the feed pitch corresponding to the resolution in the sub-scanning direction, which is the resolution of the thermal stencil printer. It has one value. For example, as shown in FIG. 8A, in the case of a heat-sensitive stencil printer having a resolution of 300 DPI (dots / inch) in both the main scanning direction S and the sub-scanning direction F, the heat generation of the heat generating portion of the thermal head used for it. The body size is 50 μm in the main scanning direction and 60 μm in the sub scanning direction.
The punching state of the heat-sensitive stencil master 61 by this thermal head is as shown in FIG. In the sub-scanning direction F
8 is considered to improve the print image quality by, for example, a resolution of 300 DPI in the main scanning direction S and a resolution of 400 DPI in the sub-scanning direction F as shown in FIG. 8B. The size of the heating element of the heating portion of the thermal head is 50 μm in the main scanning direction and 40 μm in the sub scanning direction. The punching state of the heat-sensitive stencil master 61 by this is as shown in FIG.

By the way, the plate-making time required for plate-making from the same original varies depending on the resolution in the sub-scanning direction when the line cycle of one line is the same, and becomes longer as the resolution becomes higher. That is, as described above, when printing is performed by the heat-sensitive stencil printing apparatus having a resolution of 300 DPI in both the main scanning direction and the sub-scanning direction, the print image quality is degraded but the plate making time is shortened. On the contrary, when printing is performed by the heat-sensitive stencil printing apparatus having a resolution of 300 DPI in the main scanning direction and 400 DPI in the sub-scanning direction, the plate-making time is long but the print image quality is improved.

Further, in the case of considering changing the resolution in the sub-scanning direction in the thermal stencil printing apparatus using the same thermal head, for example, as shown in FIG. When a thermal head having a resolution of 300 DPI is used in both the sub-scanning direction F, the sub-scanning direction F
When the resolution of the sub-scanning direction F is 300 DPI, the optimum perforation diameter gives a good print image quality (see FIG. 9B), but when the resolution in the sub-scanning direction F is changed to 400 DPI, each perforation is sub-scanning direction F. 9 (c), the amount of ink transferred to the printing paper increases, and the ink on the surface of the printed paper that was ejected first is printed next. There is a problem called so-called set-off which transfers to the back side of the printed sheet and stains the back side of the printed sheet.

On the other hand, for example, as shown in FIG. 10A, the main scanning direction is 300 DPI and the sub scanning direction is 400 DPI.
When a thermal head having a resolution for printing is used, when the resolution in the sub-scanning direction F is 400 DPI, the optimum perforation diameter gives good print image quality (see FIG. 1).
0 (see (c)), the resolution in the sub-scanning direction F is 300 DPI.
When changed to, the perforations are too far apart from each other in the sub-scanning direction F, and ink bleeding on the printing paper does not follow, and white streaks may occur (see FIG. 10B).

According to the embodiments shown in FIGS. 4 and 5, there is an advantage that they can be selectively used as follows. That is, the resolution in the sub-scanning direction is 300D, which requires less plate making time.
In the case of setting PI, even if white stripes such as those described in FIG. 10B occur, it is acceptable not to worry about it and to shorten the plate making time, or the amount of ink transfer to the printing paper. That is, when it is desired to reduce the ink consumption, it is necessary to set two consecutive energizing pulse widths tp2 and tp4 as in the examples shown in FIGS. 6 and 7, or in FIGS. It is not necessary to set the one energization pulse width tp5 longer than the energization pulse width tp1 as in the example shown. That is, with respect to the thermal head having a large number of heat generating portions arranged in the main scanning direction, the heat sensitive stencil master having at least the thermoplastic resin film is pressed by the platen roller, While moving the heat-sensitive stencil master by the master conveying means in the orthogonal sub-scanning direction, the heat-generating portion is caused to generate heat in accordance with the image signal, and the thermoplastic resin film is position-selectively melt-punched to obtain the image signal. A perforation pattern corresponding to the heat sensitive stencil master is wound around the outer peripheral surface of the printing drum, ink is supplied from the inner peripheral side of the printing drum, and the image signal is generated by the ink bleeding through the perforation pattern. A heat-sensitive stencil printing device for forming an ink image according to the above on a printing paper, wherein the heat-sensitive stencil master is moved at a predetermined feed pitch. The driving means for driving the master conveying means, the sub-scanning direction resolution setting means for setting the resolution in the sub-scanning direction, and the resolution in the sub-scanning direction set based on the signals from the sub-scanning direction resolution setting means. According to the signals from the drive control means for controlling the drive means so as to change to the corresponding feed pitch and the signal from the sub-scanning direction resolution setting means, the energy for perforation to be supplied to each heat generating portion of the thermal head is a predetermined energy. And a dimension of the heat generating portion in the sub-scanning direction is set to be equal to or less than the length of the feed pitch corresponding to the highest resolution that can be set by the sub-scanning direction resolution setting means. Any configuration is acceptable (claim 1
Invention described).

The embodiment of the present invention is not limited to the example in which two consecutive energizing pulse widths are set as shown in FIGS. 6 and 7, but the drilling energy adjusting means sets the drilling energy to 1 It may be adjusted such that one image signal is applied at least twice or more, that is, a plurality of times continuously (the invention according to claim 2).

Further, this heat-sensitive stencil printing apparatus can use a heat-sensitive stencil master consisting essentially of a thermoplastic resin film, for example, its thickness is 1.6.
When a hole having a diameter of μm was used to carry out perforation under the same conditions as in the above-mentioned example, similar to the above-mentioned example, independent perforation was performed without connecting each hole in the main scanning direction and the sub-scanning direction, A desired print image suitable for the resolution in the sub-scanning direction could be obtained, and a good print image without stains on the printing paper due to set-off and so-called fibres could be obtained.

The master conveying means is not limited to the system in which the platen roller 92 is driven by the master feed motor 40 as in the above embodiment, but may be a drive system as shown in FIG. 11, for example. The plate-making plate feeding unit shown in FIG. 11 is such that a master-conveying roller pair 91a, 91b as a master-conveying unit is arranged downstream of the platen roller 92 with respect to the plate-making plate feeding unit 90 shown in FIG. Become,
A master feed motor 91A as a driving unit is provided with a master conveyance roller pair 91 via a timing belt (not shown).
a and 91b are connected to the drive rollers 91a, and the master feed motor 40 connected to the platen roller 92 via a timing belt (not shown) is removed so that the platen roller 92 is driven to rotate. . According to the drive system shown in the figure, the master feed motor 91A
By the rotational driving of the master conveyance rollers 91a and 91b, the heat-sensitive stencil master 61 is conveyed and moved, and the platen roller 92 is rotated while pressing the heat-sensitive stencil master 61.

The resolution in the sub-scanning direction can be switched between 300 DPI and 400 DPI stepwise as in the present embodiment, or from 300 DPI to 400 DPI.
It is also possible to change continuously. As a means for changing the feed pitch corresponding to the resolution in the sub-scanning direction, for example, the device described in Japanese Utility Model Laid-Open No. 59-161765, that is, page 4, line 9 to page 5, of the same specification. A mechanism similar to that described in line 10 may be used.

The feeding operation for feeding the heat-sensitive stencil master in the sub-scanning direction is not limited to the intermittent movement at a predetermined feeding pitch as in the above embodiment, but may be continuously feeding. Needless to say.

In the above embodiment, at the time of reading the original, the original is read while the original conveying roller pair is rotated by the original conveying roller motor 83A to convey the original 60, but instead of this, the original is read. A method may be adopted in which the document 60 is placed and fixed on the contact glass, and the document is read while the optical system including the fluorescent lamp and the mirror is moved by the drive motor. In this case, the drive motor may be controlled so that the moving speed of the optical system is changed to a predetermined feed pitch corresponding to the resolution in the sub scanning direction.

[0084]

As described above, according to the first aspect of the present invention, when the resolution in the sub-scanning direction is set by the sub-scanning direction resolution setting means by the above configuration and operation, the perforation energy adjusting means causes the perforation energy adjusting means. , The perforation energy supplied to each heat generating portion of the thermal head is adjusted to a predetermined energy in accordance with the signal of the sub-scanning direction resolution setting means, and the perforation size in the sub-scanning direction of the heat-sensitive stencil master is appropriately large. In addition, the dimension in the sub-scanning direction of the heat generating portion is controlled to be equal to or less than the length of the feed pitch corresponding to the highest resolution that can be set by the sub-scanning direction resolution setting means. The independent perforation that is most suitable for the resolution will be performed regardless of the resolution, and it will not be connected to each sub-scanning direction and main scanning direction. Optimum print image commensurate with the scanning direction resolution can be obtained.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the drilling energy adjusting means includes:
By adjusting the perforation energy for one image signal so as to be continuously applied a plurality of times, the perforation size in the sub-scanning direction of the heat-sensitive stencil master is controlled to a more appropriate size. Further, it is possible to obtain an optimum print image that matches the set resolution in the sub-scanning direction. Further, the perforation energy adjusting means adjusts the perforation energy so as to continuously apply the perforation energy to one image signal a plurality of times, so that the peak temperature of the heating element of the thermal head is required for perforation of the heat-sensitive stencil master. Temperature to be,
That is, since the perforation size in the sub-scanning direction of the heat-sensitive stencil master can be perforated to a desired size without making the temperature higher than the threshold temperature of the heat-sensitive stencil master unnecessarily, the heat-generating portion of the thermal head is thereby formed. It is possible to reduce the heat stress applied to and to reduce it.
Therefore, the life of the thermal head can be improved.

According to the third aspect of the invention, in addition to the effect of the first aspect of the invention, the adjustment of the drilling energy is performed by the change of the energizing pulse width. When the resolution in the sub-scanning direction is set to a relatively low resolution among the resolutions that can be set by the sub-scanning direction resolution setting means, the perforation energy adjusting means,
By adjusting the perforation energy so that one energizing pulse having an energizing pulse width longer than the energizing pulse width set for a relatively high resolution is applied once to one image signal, the heat sensitivity is improved. Since the size of the perforations of the stencil master in the sub-scanning direction is controlled to a more appropriate size, it is possible to obtain an optimum print image that matches the set resolution in the sub-scanning direction. Further, the control method can be simplified more than the effect of the invention described in claim 2.

According to the fourth aspect of the invention, since the heat-sensitive stencil master consisting essentially of the thermoplastic resin film is used, in addition to the above-mentioned effects, a so-called good fiber-free printed image is obtained. be able to.

[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 diagram for explaining a configuration of a thermal head and a boring action.

FIG. 4A shows a resolution of 400 DP in the sub-scanning direction.
When I is set to I, the energization pulse width applied to the same heating element is set, and FIG. 4B shows the heating temperature transition state of the heating element of the thermal head in the same energization pulse width setting state.

FIG. 5 shows a punched state of the heat-sensitive stencil master in the states of FIGS. 4 (a) and 4 (b).

FIG. 6A shows a resolution of 300 DP in the sub-scanning direction.
When I is set to I, the energizing pulse width applied to the same heating element is set, and FIG. 6B shows the heating temperature transition state of the heating element of the thermal head in the same energizing pulse width setting state.

FIG. 7 shows a punched state of the heat-sensitive stencil master in the states of FIGS. 6 (a) and 6 (b).

FIG. 8 is a diagram for supplementarily explaining the embodiment, and FIG.
Has a resolution of 300 DP in both the main and sub scanning directions.
8B shows a case where the resolution in the main scanning direction is 300 DPI and the resolution in the sub-scanning direction is 400 D when I is set to I.
The punching state of the heat-sensitive stencil master when set to PI is shown respectively.

FIG. 9 is a diagram for supplementarily explaining the embodiment, and FIG.
Shows the heating element size of the thermal head for which the resolution in the main scanning direction and the sub-scanning direction is 300 DPI, FIG. 9B shows the case where the resolution in the sub-scanning direction is set to 300 DPI, and FIG. 9C shows the sub-scanning. The punching state of the heat-sensitive stencil master when the directional resolution is changed to 400 DPI and set is shown respectively.

10 is a diagram for supplementarily explaining the embodiment, and FIG.
10A shows a heating element size of a thermal head for a main scanning direction resolution of 300 DPI and a sub scanning direction resolution of 400 DPI, and FIG. 10B shows a sub scanning direction resolution of 30.
FIG. 10C shows the punching state of the heat-sensitive stencil master when the resolution in the sub-scanning direction is set to 400 DPI when the setting is changed to 0 DPI.

FIG. 11 is a configuration diagram of a plate making and plate feeding section showing a modified example of the master conveying means.

FIG. 12 is a diagram illustrating another example of the above embodiment,
FIG. 12A shows the setting state of the energization pulse width applied to the same heating element when the resolution in the sub-scanning direction is set to 300 DPI, and FIG. 12B shows the thermal state in the setting state of the same energization pulse width. The heat generation temperature transition state of the heating element of the head is shown.

FIG. 13 is a diagram for explaining the characteristics of the other example in comparison with the embodiment, and FIG. 13A is a plan view showing an arrangement state of heating elements of the thermal head.
FIG. 13B shows the difference in the temperature distribution state of the heating element due to the difference in the setting of the energization pulse width, and FIG. 13C shows the difference in the punching state of the heat-sensitive stencil master due to the difference in the setting of the energization pulse width. .

DESCRIPTION OF SYMBOLS 1A Heat generating element in heat generating portion of thermal head 10 Sub-scanning direction resolution setting key 20 as sub-scanning direction resolution setting means 20 Microcomputer as drive control means and perforation energy adjusting means 30 Thermal head 40 As drive means Master feed motor 61 Heat-sensitive stencil master 92 Platen roller as master conveying means 101 Printing drum 107 Ink pool F Sub-scanning direction S Main scanning direction tp1, tp2, tp4, tp5 energizing pulse width (energizing time) tp3 energizing off time

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B41N 1/24 102

Claims (4)

[Claims] 1. A heat sensitive stencil master having at least a thermoplastic resin film is pressed by a platen roller against a thermal head having a large number of heat generating elements arranged in the main scanning direction. While moving the heat-sensitive stencil master by the master conveying means in the sub-scanning direction orthogonal to the scanning direction, the heat-generating portion is caused to generate heat in accordance with the image signal, and the thermoplastic resin film is position-selectively melt-punched. Obtaining a perforation pattern according to the image signal, this heat-sensitive stencil master is wound around the outer peripheral surface of the printing drum, ink is supplied from the inner peripheral side of the printing drum, and the ink bleeds through the perforation pattern. In a heat-sensitive stencil printing apparatus for forming an ink image on a printing paper according to the image signal, the heat-sensitive stencil master is moved at a predetermined feed pitch. Drive means for driving the master transport means, sub-scanning direction resolution setting means for setting the resolution in the sub-scanning direction, and resolution in the sub-scanning direction set based on the signal from the sub-scanning direction resolution setting means. Drive control means for controlling the drive means so as to change the feed pitch corresponding to the above, and in accordance with a signal from the sub-scanning direction resolution setting means, the perforation energy to be supplied to each heat generating portion of the thermal head is set to a predetermined value. And a perforation energy adjusting means for adjusting the energy, the dimension in the sub-scanning direction in the heat generating portion is equal to or less than the length of the feed pitch corresponding to the highest resolution that can be set by the sub-scanning direction resolution setting means. A heat-sensitive stencil printing device characterized by the above. 2. The heat-sensitive stencil printing apparatus according to claim 1, wherein the perforation energy adjusting means adjusts the perforation energy so as to be continuously applied to one image signal a plurality of times. Heat sensitive stencil printer. 3. The heat-sensitive stencil printing apparatus according to claim 1, wherein the adjustment of the perforation energy is performed by changing the energization pulse width, and the resolution in the sub-scanning direction is: When the resolution is set to a relatively low resolution among the resolutions that can be set by the sub-scanning direction resolution setting means, the perforation energy adjusting means sets 1
The energy for punching is adjusted so that an energizing pulse having an energizing pulse width longer than the energizing pulse width set corresponding to a relatively high resolution is applied once to one image signal. Heat sensitive stencil printer. 4. The heat-sensitive stencil printing apparatus according to claim 1, 2, or 3, wherein the heat-sensitive stencil master is substantially composed of a thermoplastic resin film.