JPH0839752A - Plate-making device - Google Patents

Abstract

PURPOSE:To obtain a plate-making device which can print excellently by using a plate-making means also as a printing means for printing on a thermosensible medium, printing at the lowest dot pitch, and making a plate at a pitch longer than the pitch of printing so as to print without gaps between dots. CONSTITUTION:In a thermal head 5, rectangular heat generating bodies 6 are arranged in a row in the horizontal scanning direction, electrodes 7 are connected to both ends in the vertical scanning direction of each heat generating body 6, and power is supplied to the heat generating bodies 6. As for size and dot pitch of each heat generating body 6, a resolving power double that of print character or punch hole which is set in a plate-making device is provided. While a resolving power as a device is 200 dpi (dot/inch), a horizontal scanning length a is 47mum, a vertical scanning length b is 80mum, and the lowest dot pitch in the horizontal scanning direction is 63.5mum as the size of each heat generating body 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate making apparatus for making a plate on a heat-sensitive medium by a plurality of heating elements such as a thermal head, and more particularly to an apparatus which also serves as a printing apparatus.

[0002]

2. Description of the Related Art Conventionally, in a plate making apparatus, a thermal head composed of a plurality of heating elements is brought into contact with the thermoplastic resin film side of a heat-sensitive stencil sheet made by laminating a thermoplastic resin film and a porous support. It is known to make a plate by making holes in a heat-sensitive stencil sheet. FIG. 6 is a schematic configuration diagram of the plate making device. The heat-sensitive stencil sheet 21 is
It is conveyed in the direction of arrow A while being nipped by the conveyance rollers 22 and 23, and is inserted between the platen roller 24 and the thermal head 25. The thermoplastic resin film 21a of the heat-sensitive stencil sheet 21 is in a state of being in direct contact with the heating element 26 provided in the thermal head 25, whereby the thermoplastic resin film 21a of the heat-sensitive stencil sheet 21 is perforated to make a plate. To be done.

Generally, when the heating element 26 provided in the thermal head 25 is energized, the heating element 26 generates heat, and the temperature of the thermoplastic resin film 21a which is in direct contact with the heating element 26 rises accordingly. To do. Then, when the temperature exceeds the shrinkage start temperature ta, minute holes are generated in the thermoplastic resin film 21a to grow. On the other hand, the heating element 2
When the energization of 6 is completed, the heating element 26 radiates heat, and when the temperature of the thermoplastic resin film 21a falls below the shrinkage stop temperature tb (ta> tb) in association with this, the growth of the openings in the thermoplastic resin film 21a grows. It has stopped and the openings are set to solidify.

FIG. 7 shows the dot size at each stage when the heat-sensitive stencil sheet 21 is thermally perforated by the thermal head 25 and printed. (A) is the size of the heating element 26 of the thermal head 25, (b) is the size of the perforations of the heat-sensitive stencil sheet 21 after plate making by the heating element 26, (c) is the printing size due to ink bleeding after stencil printing (Spread of ink)
Is shown. The size of the perforations in the heat-sensitive stencil sheet 21 is almost the same as the size of the heating element 26 of the thermal head 25. However, when stencil printing is performed using the heat-sensitive stencil sheet 21 having this perforation size, the spread of ink on the paper It gets quite large.

FIG. 8 shows the dot size at each stage when printing is performed on thermal paper using the same thermal head 25. (A) shows the size of the heating element 26 of the thermal head 25, and (b) shows the printing size by coloring the thermal paper after printing by the heating element 26. The size of the colored portion of the thermal paper is almost the same as the size of the heating element 26 of the thermal head 25.

FIG. 9A is a schematic plan view of a thermal head 25 used in a conventional printing apparatus. The thermal head 25 shown here is a thermal head for printing as used in a conventional facsimile apparatus, in which rectangular heating elements 26 are arranged in a line in the main scanning direction. Electrodes 27 are connected to both ends in the sub-scanning direction orthogonal to the main-scanning direction to supply electric power to the heating element 26. Such a thermal head 2
When a solid pattern is printed on the thermal paper using
As shown in (b), good printing without gaps between dots can be obtained.

By the way, for making the heat-sensitive stencil sheet 21,
When the thermal head 25 used in the conventional printing device is used, since the applied energy per unit area applied to the heat-sensitive stencil sheet 21 is large, a gap portion with the gap contact dot in the main scanning direction on the thermoplastic resin film 21a. In some cases, the surface temperature of the above may exceed the shrinkage stop temperature tb. In this case, the aperture generated at the center of each dot grows to the periphery and reaches the adjacent dot without stopping at the gap between the dots. That is, continuous apertures are formed in the main scanning direction.

As a result, when a solid pattern is formed on the heat-sensitive stencil sheet 21, large open pores are formed without gaps in the main scanning direction and the sub-scanning direction, and the melted and floating fluid film is supported by the support. Entanglement the fibers to form the film membrane or film mass again. This causes formation of an unnecessary white image portion on the black image portion at the time of printing, and there is a problem that so-called Japanese paper appears on the print image. In addition, the amount of ink transferred to the printing paper through the large opening formed as described above is larger than that of the other image area, and this is the amount of ink of the printing paper that is printed next and stacked on top. There is a problem in that the so-called show-through phenomenon is made conspicuous by staining the back side. Further, not only the solid pattern but also the character image and the line image are composed of dots that are continuous in the vertical and horizontal directions, so that the dot aperture portion may become large as described above. In this case, there is a problem that the amount of ink transferred to the printing paper through the film is large, and the character image and the line image become considerably thicker or crushed as compared with the original image.

Therefore, as a thermal head used in a plate making apparatus, there is one described in JP-A-2-67133. This is as shown in FIG.
The length of each heating element 26 of the thermal head 25 in the sub-scanning direction is configured to be shorter than the dot pitch in the main scanning direction, and between the dot perforations in the sub-scanning direction formed in the thermoplastic resin film of the heat-sensitive stencil sheet. A gap portion composed of an unprinted plate portion is provided at. This thermal head 25
When you make a solid pattern on heat-sensitive stencil paper using
As shown in FIG. 10B, in the main scanning direction and the sub-scanning direction, independent apertures are obtained without forming continuous apertures, and stencil printing in this perforated state results in good solid printing. can get.

[0010]

However, when a mechanism as a printing device is added to the plate-making apparatus having the above-mentioned structure and the same thermal head as that at the time of plate-making is used to print a solid pattern on the thermal paper, as described above. In addition, since the size of the color-developed portion of the thermal paper by one dot is almost the same as the size of the heating element of the thermal head, printing is performed with a gap between the dots, and good printing cannot be obtained. That is, the thermal head in the conventional plate-making apparatus is dedicated to plate-making and cannot be used also for printing.

The present invention has been made in order to solve the above problems, and enables the same apparatus to perform both plate making on a heat-sensitive stencil sheet and printing on a heat-sensitive sheet, and at the time of plate making of the heat-sensitive stencil sheet. An object of the present invention is to provide a plate making apparatus capable of excellent printing and printing by making a plate with holes between the dots having a gap and performing printing with no gap between dots when printing on thermal paper.

[0012]

In order to achieve this object, the plate making apparatus of the present invention makes a plate by making a dot-like perforation on a heat-sensitive medium by heating a plurality of heating elements arranged in the main scanning direction. In a plate making apparatus comprising plate making means for performing, and a moving means for relatively moving the heat-sensitive medium and the heating element in a sub-scanning direction orthogonal to the array direction of the heating element,
The plate making means is also used as a printing means for printing on the heat-sensitive medium, and at the time of printing, the relative movement pitch of the heat-sensitive medium and the heating element in the sub-scanning direction is printed at the minimum dot pitch, and the plate making is carried out. At this time, the heating drive of the heating element is thinned out in the main scanning direction, and the relative movement pitch in the sub scanning direction is made longer than the pitch at the time of printing for plate making.

[0013]

According to the plate making apparatus of the present invention having the above structure, when the plate making means prints on the heat sensitive medium by heating a plurality of heating elements arranged in the main scanning direction, the heat sensitivity of the moving means is increased. The pitch of the relative movement of the medium and the heating element in the sub-scanning direction is set to the minimum dot pitch. Further, when the plate making means performs the plate making by making a dot-shaped perforation on the heat-sensitive medium, the heating drive of the heating element is thinned out in the main scanning direction, and the sub-scanning direction of the heat-sensitive medium and the heating element by the moving means is also thinned. The pitch of relative movement of is longer than the pitch at the time of printing. As a result, there is no gap between dots when printing,
Further, during plate making, a plate is made in which perforations between dots have a gap.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a schematic plan view of a thermal head 5 used in the plate making apparatus of this embodiment, and FIG. 1B is a thermal paper when a solid pattern is printed by the thermal head 5. The color-developed state, (c) shows the perforated state of the heat-sensitive stencil sheet 1 when a solid pattern is produced by the thermal head 5. In the thermal head 5, rectangular heating elements 6 are arranged in a line in the main scanning direction, electrodes 7 are connected to both ends of each heating element 6 in the sub scanning direction, and power is supplied to the heating elements 6. It has become so. The size and dot pitch of each heating element 6 are configured to have a resolution twice as high as the resolution of printing or punching set in the plate making device. Specifically, the resolution of the device is 200 dp
In contrast to i (dots / inch), each heating element 6 has a main scanning length a of 47 μm and a sub-scanning length b of 80 μm.
And the minimum dot pitch in the main scanning direction is 63.5 μm
It is configured so that Further, the feed pitch in the sub-scanning direction is 63.5 μm, which is 40
It will have a resolution of 0 dpi.

FIG. 2 is a block diagram of the control unit of this apparatus and the control circuit of the thermal head. The input unit 10 controls the input of data from an external device (not shown). For example, RS-
Input data 11 such as print data or image data is input by a signal conforming to the 232C interface, or a control signal 12 for controlling data input from an external device is input. Printer control unit 1
Reference numeral 3 controls the entire apparatus based on the input data 11 from the input unit 10. The paper feed unit 14 drives a paper feed motor (not shown) in accordance with a paper feed command from the printer control unit 13 based on the input data to supply the heat-sensitive stencil sheet or the heat-sensitive paper. The sensor 15
A detector for detecting the operating state of the device, for example,
A plurality of detectors for detecting the presence / absence of printing paper and for detecting the temperature of the thermal head 5 are shown. The detection signals from these detectors are sent to the printer control unit 13
Sent to and used to control the printer.

The shift register 16 includes a transmission clock (CLK) 17 for serial data sent from the printer control unit 13 and one line of serial printing for driving the thermal head 5 synchronized with the clock 17. The data (DATA) 18 is stored. The latch circuit 19 latches the data for one line by the latch signal (LA) 20 output from the printer control unit 13 when the transmission of the data for one line is completed. The data for one line holds information as to whether or not each heating element 6 of the thermal head 5 generates heat. The thermal head 5 has a printer controller 13
The electric current from the power source 8 is applied to the heating element 6 only while the strobe signal (STR) 9 output from the thermosensitive stencil sheet is in the active state. To color.

Next, the plate making operation of the heat-sensitive stencil sheet and the printing operation of the heat-sensitive paper in this plate making apparatus will be described with reference to FIG. Note that the content described in the flowchart of FIG. 3 is a portion related to plate making or printing, and the operation before that is the same as the control in the conventional art, and therefore the description is omitted.

First, 400 lines are used for plate making or printing.
The value of the line counter for counting the number of lines corresponding to the resolution of dpi is set to 0 as an initial value (S1). Next, after adding 1 to the value of the line counter (S2), it is determined whether or not plate making is performed (S3). If it is plate making operation (YES at S3), the current line counter value is 2N (N). Is an integer), that is, it is determined whether it is an even number (S4).

If the value of the line counter is not an even number in S4 (NO in S4), the data for one line to be punched next is expanded (S5), and the data of one line in the main scanning direction out of the expanded data. The even-numbered data in the transmission order of is replaced with 0 (S6). That is, even-numbered heating elements 6 of the thermal head 5 are replaced with data 0 so as not to generate heat even when the strobe signal 9 is turned on. Next, the data is sent to the thermal head 5 (S7), and the strobe signal 9 is turned on to punch one line (S8). 1
When the perforation for the lines is completed, the heat-sensitive stencil sheet is fed for one line in the sub-scanning direction (S9), and it is determined whether the value of the line counter is 2M (the total number of lines of the original to be made) (S10). In S10, the line counter value is 2
When M (total number of lines) is reached, the plate making operation is ended, but when it is not reached, the process returns to S2 and the above operation is repeated.

If the value of the line counter is an even number in S4 (YES in S4), all the data for driving the thermal head 5 are replaced with 0 (S11), and the data is sent to the thermal head 5 (S12). , The strobe signal 9 is turned on to punch one line (S1
3). However, since the data are all 0, there is no part that is actually punched. When perforation for one line is completed, the process proceeds to S9 and the above-mentioned operation is performed.

In S3, if it is not a plate making operation (NO in S3), that is, if it is a printing operation, it is determined whether or not the current line counter value is 2N (N is an integer), that is, an even number. Yes (S14). In S14,
If the value of the line counter is not an even number (N in S14
O), and develops the data for one line to be printed next (S1
5) The expanded data is sent to the thermal head 5 (S16). Then, the strobe signal 9 is turned on to print one line (S17).

When the printing of one line is completed, the process proceeds to S9, the thermal paper is fed by one line in the sub-scanning direction, and it is determined whether the value of the line counter is 2M (the total number of lines of the document to be printed) ( S10). In S10, when the value of the line counter reaches 2M (total number of lines), the printing operation is ended, but when the value is not reached, the process returns to S2 and the above operation is repeated.

If the value of the line counter is even in S14 (YES in S14), the data sent to the thermal head 5 is the same as the data of the odd line one line before, so S15 is selected. Skip S16
The process proceeds to (1) and outputs the data of the odd line one line before to the thermal head 5, and the above-mentioned operation is performed.

An example of characters printed or printed by the above operation is shown in FIGS. FIG. 4 shows the printing result, and FIG. 5 shows the punching result obtained by the plate making operation. In FIG. 5, the blackened portions of the dots are the perforated portions. The character "B" is formed in an area of 48x48 dots with a dot resolution of 400 dpi, but the actual character is 200d with 2x2 dots as the minimum unit dot.
It is configured in a 24 × 24 area with a pi resolution.

As described above, the plate making apparatus of this embodiment is constructed so that the resolution of the thermal head 5 and the resolution in the sub-scanning direction are twice the desired resolution of 200 dpi. When printing on the thermal paper, the heating drive of the heating element 6 is not skipped in the main scanning direction, and
Since the thermal paper is fed in the sub-scanning direction at the minimum feed pitch of 63.5 μm, good printing without gaps between adjacent dots can be obtained. Further, when performing plate making on the heat-sensitive stencil sheet, the heating drive of the heating element 6 is thinned out every other dot in the main scanning direction, and at the same time, the plate is made every other line in the sub-scanning direction. Gaps can be provided in the perforations between adjacent dots, and as a result of stencil printing, print with less bleeding and without show-through is obtained.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the present embodiment, the resolution of the thermal head 5 and the resolution in the sub-scanning direction are doubled with respect to the resolution set in the plate making apparatus, but the printing state during plate making is further improved. Therefore, the resolution may be further increased.

[0028]

As is apparent from the above description, in the plate making apparatus of the present invention, the heat-sensitive medium is perforated in a dot shape by heating a plurality of heating elements arranged in the main scanning direction to perform plate making. It is also possible to print by plate making means,
At the time of printing, the pitch of the relative movement of the heat-sensitive medium and the heating element in the sub-scanning direction is printed at the minimum dot pitch, and at the time of plate making, the heating drive of the heating element is thinned out in the main scanning direction and the sub-scanning is performed. Make the plate by making the pitch of relative movement in the direction longer than the pitch during printing. This makes it possible to provide gaps between adjacent dots when making perforations when making a heat-sensitive stencil sheet, and as a result of stencil printing, printing without show-through with little bleeding can be achieved. Good printing with no gaps can be obtained.

[Brief description of drawings]

FIG. 1A is a schematic plan view of a thermal head used in a plate making apparatus of the present embodiment, and FIG. 1B is a diagram showing a color development state of a thermal paper after printing a solid pattern,
(C) is a diagram showing a perforated state of the heat-sensitive stencil sheet after plate making of the solid pattern.

FIG. 2 is a block diagram showing a control unit of the apparatus and a control circuit of a thermal head.

FIG. 3 is a flowchart showing a plate making operation of the heat-sensitive stencil sheet and a printing operation of the heat-sensitive paper in this apparatus.

FIG. 4 shows an example of characters for plate making or printing by this device,
It is a figure showing a printing result.

FIG. 5 is a diagram showing a punching result obtained by a plate making operation of the present apparatus.

FIG. 6 is a schematic configuration diagram of a conventional plate making apparatus.

FIG. 7 is a diagram showing dot sizes at each stage in stencil printing, where (a) is a size of a heating element, (b) is a size of perforations after plate making of the heat-sensitive stencil sheet, and (c) )
FIG. 6 is a diagram showing a print size due to ink bleeding after stencil printing.

FIG. 8 is a diagram showing dot sizes at respective stages when printed on thermal paper, in which (a) is a size of a heating element,
(B) is a diagram showing a print size by color development of the thermal paper after printing.

FIG. 9A is a schematic plan view of a thermal head used in a conventional printing apparatus, and FIG. 9B is a diagram showing a color development state of the thermal paper after printing a solid pattern.

10A is a schematic plan view of a thermal head used in a conventional plate making apparatus, and FIG. 10B is a diagram showing a perforated state of a heat-sensitive stencil sheet after plate making of a solid pattern.

[Explanation of symbols]

 5 Thermal Head 6 Heating Element 13 Printer Control Section 14 Paper Feed Section 16 Shift Register 19 Latch Circuit

Claims (1)

[Claims] 1. A plate making means for making a plate by making a dot-like perforation in a heat-sensitive medium by heating a plurality of heating elements arranged in the main scanning direction, and a sub-scanning direction orthogonal to the arrangement direction of the heating elements. In a plate making apparatus comprising a moving means for relatively moving the heat sensitive medium and the heating element, the plate making means is also used as a printing means for printing on the heat sensitive medium, and at the time of printing, the heat sensitive medium And a pitch of relative movement in the sub-scanning direction with the heating element is printed at a minimum dot pitch, and at the time of plate making, the heating drive of the heating element is thinned out in the main scanning direction, and the pitch of relative movement in the sub-scanning direction. A plate-making device, which makes a plate longer than the pitch at the time of printing.