JPH0673950B2 - Stencil plate making machine and printing machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil plate making apparatus for a copy plate in which a stencil sheet is thermally perforated by a thermal head, and a printing apparatus for printing using the stencil sheet.

2. Description of the Related Art Recently, a copy printing system has become popular. This is because the running cost is lower than that of a copying machine when printing a large number of sheets. Also, there is an advantage that the plate making can be performed at a lower cost and more easily than other printing systems.
As a copy printing system, for example, there is a flash exposure type base paper plate making apparatus. In this method, an original is superposed on a base paper and then a flash plate is made. However, this has problems that the plate making operation is time-consuming, the document is apt to be damaged, and the plate making defect is likely to occur in a color document having a poor infrared absorption rate.

Further, a stencil plate making machine using a wire dot printer or a double-current type (copying type) printer has already been put into practical use. These have an advantage that the manuscript can be easily created by combining with a word processor, for example. However, the former stencil plate making machine with a wire dot printer has the problems that the plate making speed is slow and the sound during plate making is noisy, while the latter stencil plate making machine with a double-current printer also has a slow plate making speed and produces a foul odor during plate making. There is a problem that it occurs.

As a solution to the above problem, a plate making process using a thermal head is proposed in JP-A-55-103957. According to the plate making process by the thermal head, the base paper is thermally perforated in an image shape, the perforated base paper (master) is superposed on the paper, and ink is supplied from the master side to print.

Problems to be Solved by the Invention However, the problem of the plate-making process is that the perforation layer of the base paper adheres to the surface of the heating resistor of the thermal head, and the perforation quality deteriorates. As a means for solving this problem, in the above publication, a paper is interposed between the thermal head and the base paper, or the thermal head is brought into contact with the base paper layer side of the base paper so that the thermal head and the perforation layer of the base paper are directly connected to each other. A method of preventing contact is presented. However, in these solutions, most of the heat from the thermal head is reflected, absorbed or diffused in the base paper layer of the paper or base paper between the thermal head and the perforation layer, and as information reaching the perforation layer. The amount of heat is extremely small, and the perforation quality is significantly reduced as compared with the case of directly perforating the perforation layer. Therefore, there has been a strong demand for a method in which the perforation layer does not adhere to the thermal head even when the perforation layer is directly perforated by the thermal head.

The inventor investigated the cause of the deterioration of the perforation quality in the plate making process using the thermal head, and first completed the plate making process using the thermal head. Next, the optimum thermal head driving conditions were experimentally determined for each of thermal printing and stencil plate making, and the present invention was completed.

An object of the present invention is to prevent the base paper from adhering to the thermal head during the punching of the base paper to improve the punching quality.

Means for Solving the Problems In order to achieve the above-mentioned object, the stencil plate making apparatus of the present invention comprises a stencil plate making mechanism for punching the stencil making stencil sheet by a thermal head, and at least at the time of making the stencil sheet, feeds the stencil sheet. For applying a driving pulse to the driving means for applying a perforation pulse to the thermal head is 5.83 ms.
It is set to ec or less, and the time until the base paper feed drive pulse is applied after the end of the application of the punching pulse is set to 0.83 msec or more.

The printing apparatus of the present invention is provided with a base paper plate making mechanism for punching a base paper for a copy plate by a thermal head, and at least at the time of making the base paper, a drive pulse is applied to a drive means for feeding the base paper, and then a punching pulse is applied to the thermal head. The time until it is set to 5.83 msec or less, and the time until the base paper feed drive pulse is applied after the completion of the perforation pulse application is set to 0.83 msec or more, respectively, and a thermal print mechanism for performing thermal printing with a thermal head is provided, and at the time of thermal printing. And means for independently setting the thermal head driving conditions during stencil plate making.

According to the stencil plate making apparatus of the present invention, at least at the time of stencil plate making, the time Ta from the stencil sheet stencil (base paper) feed drive pulse application to the piercing pulse application at the punching timing by the thermal head is 5.83 msec or less and the piercing pulse is applied. The time Tb until the stencil base paper feed drive pulse is applied after the pulse application is completed is 0.83 msec or more. This reduces the adhesion of the molten resin of the stencil base paper to the thermal head, thus delaying the deterioration of the thermal head.

Further, the printing apparatus of the present invention is provided with means for independently setting the thermal head driving conditions during thermal printing and during stencil plate making. As a result, the thermal head drive can be switched between thermal printing and stencil plate making, so that independent control can be performed during thermal printing and stencil plate making. Therefore, even if the ink donor film has different printing characteristics or the stencil base paper has different perforation characteristics,
It is possible to always obtain stable and good thermal print quality and stencil punching quality, that is, stencil print quality.

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

FIG. 1 shows an embodiment of a stencil plate-making device which also serves as a thermal printer. When printing a small number of copies, the thermal printing mechanism is operated to create a desired number of copies, and when printing a large number of copies, the stencil plate making mechanism is operated to create an original plate for stencil printing, and then a desired number of copies are printed.
First, the stencil plate making mechanism will be described.

Insert the stencil base paper from the stencil base paper insertion port 18,
When the leading end of the stencil base paper hits the timing roll 13, a thermal head isolating means (not shown) is activated by a signal from the stencil base paper sensor 19 to move the thermal head 1 upward in the drawing so as to move between the platen roll 2. There is a slight gap in the area. After t1 seconds, the timing roll 13 rotates, and the stencil base paper is conveyed for a predetermined time (t2 seconds) until the leading edge hits the stencil base paper resist roll 14. After the lapse of the predetermined time (t2 seconds), the rotation of the timing roll 13 is stopped, the operation of the thermal head isolating means (not shown) is stopped, and the thermal head 1 moves downward in the drawing to move between the platen roll 2 and the platen roll 2. A predetermined pressure is applied. At this point, a "plate-making ready" lamp (not shown) on the operation panel (not shown) is turned on. When a "plate-making" button (not shown) is pressed, a "plate-making" button (not shown) is lit, and data signal acquisition from the host computer (not shown) is started. At the same time as printing from the thermal head 1, the stencil base paper and the ink donor film 3 are overlapped by the rotation of the platen roll 2 and conveyed in the direction of arrow A.
The timing roll 13, the stencil base paper resist roll 14, and the ink donor supply roll 6 are driven in synchronization with the rotation of the platen roll 2 so that the stencil base paper and the ink donor film 3 are not loosened or overtensioned. The stencil base paper is separated from the ink donor film 3 by 14 parts of the stencil base paper resist roll, and the stencil base paper discharge tray 16 discharges the stencil base paper discharge roll 15.
The ink donor film 3 is wound from the ink donor film winding roll 7 to the ink donor film supply roll 6.

The stencil base paper sensor 19 provided on the stencil base paper insertion opening 18 side of the timing roll 13 detects the rear end of the stencil base paper, and after t3 seconds elapse, the output of the thermal head 1 is stopped, and further after t4 seconds. All drive stopped,
The "making plate" lamp (not shown) goes out.

FIG. 3 shows a block diagram for switching the driving conditions of the thermal head 1. The switching circuit 31 includes a thermal head applied voltage setting knob for thermal printing and stencil plate making, and an applied pulse width setting dip switch. The applied voltage and the applied pulse width are set according to the resistance value of the thermal head 1, the thermal printing characteristics of the ink donor film 3, and the punching characteristics of the stencil base paper. On the other hand, when the "thermal print button" or the "stencil plate making button" is pressed, a signal is issued from the drive start signal generation circuit 30, the switching circuit 31 is activated, and the thermal head 1
A drive signal under drive conditions for either thermal printing or stencil platemaking is applied to.

Next, the thermal (thermal transfer) printing mechanism will be described with reference to FIG. 1. First, an operation panel (not shown)
When the upper "print" button (not shown) is pressed, the "printing" lamp (not shown) lights up, and the paper supply roll 8
Is rotated and the sheet 4 is conveyed until the leading edge of the sheet 4 is abutted against the sheet registration roll 9 to form a slight loop on the sheet 4. Paper sensor in front of paper registration roll 9
The rotation of the paper supply roll is stopped t5 seconds after 20 detects the leading edge of the paper 4, and at the same time, the rotation of the paper registration roll 9 and the paper transport roll 10 is started, and the platen roll 2 and the ink donor film take-up roll are also started. 7 starts to rotate. Then, after t6 seconds, the leading edge of the paper 4 reaches the print area, the data signal from the host computer (not shown) is started to be read, the printing from the thermal head 1 is started, and the paper 4 becomes the ink donor film 3. The sheets are superposed and sent in the direction of arrow B, separated from the ink donor film 3 by the sheet separating roll 17 part, pass through the sheet discharging roll 11, and are discharged to the sheet discharging tray 12. The output of the thermal head 1 is stopped 7 seconds after the paper sensor 20 detects the trailing edge of the paper 4, the driving is stopped after 8 seconds, the "printing" lamp (not shown) is turned off, and "printing" is performed. The READY lamp lights up.

When the stencil plate making mechanism is operated by the plate making / print switching circuit, the thermal transfer printing mechanism does not work even if the "print" button (not shown) is pressed. When the mechanism is operating, the stencil plate making mechanism does not operate even if the stencil base paper is inserted from the base paper insertion port 18.

Further, the images of the stencil original plate and the thermal transfer print need to have a mirror image relationship with each other, but as shown in FIGS. 8A and 8B, the traveling direction A of the stencil base paper 5 and the thermal transfer print are shown. A mirror image relationship can be obtained by reversing the traveling direction B of the sheet of paper 4.

FIG. 4 shows an enlarged conceptual view of the punched portion by the thermal head 1. The thermal head 1 comprises a heat storage layer 1e (SiO ₂ , 40 μ thick) on a glaze alumina (Al ₂ O ₃ ) base 1f, a common electrode 1c obtained by etching an Au film, a signal electrode 1d (4 μ thick), a heating resistor 1a ( RuO ₂ particles adhere to the surface of PbO ・ SiO ₂・ B ₂ O ₃ glass particles, 15-25 μm thick), and wear resistant layer 1b (SiO ₂・ Al ₂ O ₃ ,
4 to 10 μm thick). Here heat storage layer 1e, Au
The film, the heating resistor 1a and the abrasion resistant layer 1b are formed by screen printing, drying and baking.

The stencil base paper 5 is formed by laminating a stretched synthetic resin film (perforated layer) 5a on a porous base layer 5b. As the stretched synthetic resin film 5a, for example, vinylidene chloride-based copolymer resin, polyvinyl chloride and vinyl chloride-based copolymer resin, polyethylene terephthalate, polypropylene, polystyrene, or synthetic resin such as polyethylene and ethylene vinyl acetate copolymer is used. A film having a thickness of 2 to 20 μm drawn by the inflation method or the biaxial drawing method is used. As the porous base layer 5b, for example, gauze made of fibers such as Tetron, nylon, silk, rayon, and cotton, and non-woven fabric made of glass fiber, asbestos, natural or artificial fiber, which has a relatively high melting point and is resistant to A material having excellent printing property and good ink permeability is used. For bonding the stretched synthetic resin film 5a and the porous base layer 5b, a thermoplastic synthetic resin solution such as a vinyl acetate-based copolymer, a vinyl chloride-based copolymer, or a vinylidene chloride-based copolymer is generally used as an adhesive. What is used is used.

A partially enlarged view of the heating resistor is shown in FIG. When a perforation pulse is input to a specific signal electrode 1d, a current flows between the signal electrode 1d and each of the common electrodes 1c on both sides for the duration of the perforation pulse width, and the heating resistor 1a generates heat (300 to 400 ° C). ) Do. The heat melts the perforated layer 5a of the stencil base paper 5 to open holes,
Since the perforation layer 5a is made of a stretched resin film, the holes are further expanded. Under optimum perforation conditions, the final perforation size is 125-175μ in diameter (with a thermal head of 8 dots / mm). The resin film around the holes is in a high temperature / melted state for a while, and has a characteristic that it is very easy to adhere to the surface of the wear resistant layer 1b as the upper layer of the heating resistor 1a. A driving pulse is applied to the stepping motor after Tb (msec) has elapsed after the application of the punching pulse, and the stencil base paper 5 is set to 1
The line is sent. At this time, the molten resin film around the perforated portion rubs the surface of the wear resistant layer. Then, the new perforation layer 5a is preheated by the residual heat of the heat generating resistor 1a, and is in a state of being easily perforated. When Ta (msec) has passed after the drive pulse was applied to the stepping motor, the punching pulse is input to the specific signal electrode 1d. The above steps are repeated.

It is considered that the above-mentioned molten resin around the perforation causes the deterioration in the perforation of the stencil base paper 5 even with the applied power, which does not cause the deterioration of the heating resistor 1a in the case of thermal paper printing.

That is, one idea is that if Tb is short, the molten resin adheres to the surface of the wear resistant layer 1b by rubbing without solidifying, and this serves as an adhesive, and the perforated layer 5a is fixed to the surface of the wear resistant layer 1b.
Then, the abrasion resistant layer 1b and the heating resistor layer 1a are peeled off by feeding the stencil base paper 5. At this time, if Ta is long, the perforation layer is firmly fixed.

Another idea is that when the perforated layer 5a rubs the surface of the abrasion resistant layer 1b, the perforated layer 5a and the base paper base layer 5b, the molten resin of the adhesive of the perforated layer 5a once adheres to the abrasion resistant layer 1b surface, and then wear resistant. Assuming that it penetrates into the heating resistor 1a through the pinhole of the layer 1b, the longer Ta is, the larger the penetration amount is, and when Tb is shorter, the viscosity of the molten resin is lower, so that the penetration speed becomes faster. It is a translation.

According to the result of the experiment, under the condition of the drilling timing within the range of Ta ≦ 0.83msec and Tb ≧ 0.83msec, 1,000 sheets (400mm
The quality of the printed matter using the original plate after plate making was good.

However, if Ta is made too short, the pre-heating of the perforation layer 5a will be poor and the perforation quality will deteriorate. Ta ≧ 0.83msec seems to be appropriate from the viewpoint of drilling quality, but the drilling quality is platen roll 2
The Ta · min cannot be unconditionally determined because it can be improved by increasing the pressing force of, the thickness of the perforated layer 5a, and the like. Further, the drive division number of the thermal head 1 depends on the power source capacity, but the maximum division number is also determined from Ta · max. If the maximum number of divisions is decided, Tb / max will be decided naturally. For example, when the perforation pulse width Tw = 1 msec, the maximum number of divisions is 6, and Tb · max = 5.83 (Tb ≦ 5.83). Tw = 2ms
When ec, the maximum number of divisions is 3, and Tb · max = 4.83 (Tb ≤ 4.8
3) becomes.

As shown in FIG. 7, the stencil base paper 5 is actually fed with a certain time delay from the application of the stepping motor drive pulse. This is stencil base paper 5
-Slip between platen rolls 2, expansion and contraction of stencil base paper 5, mechanical association, etc. Here, the area of the profile of the moving speed of the stencil base paper 5 is the moving amount of one step. In short, the time Ta 'from the complete stop of the stencil base paper 5 to the application of the punching pulse and the time Tb' from the start of the movement of the stencil base paper 5 after the application of the punching pulse.
Is desirable if However, this delay amount varies depending on the configuration of the driving device, the stencil base paper 5, the material of the platen roll, and the like.

In general, ΔTa = Ta−Ta ′ ≧ 0 ΔTb = Tb−Tb ′ ≦ 0, and what is important here is even if ΔTa and | ΔTb |
That is, even if is large, if Ta and Tb are in a specific range, deterioration of the heating resistor 1a can be prevented. If Ta and
Heating resistor 1a, even though Tb is in the specified range
If the perforation quality is poor even though the surface temperature is normal, the reason is that the stencil base paper 5 has a large delivery delay and ΔTa is large.
Limiting Ta and Tb is practical as described above, and is also effective in taking appropriate measures when a problem occurs.

Figure 9 shows Ta and the number of plates made before the start of white streaks, and Figure 10 shows
Ta and the printing density of the 1,000th original plate, Fig. 11 shows the relationship between Tb and the number of plates, and Fig. 12 shows the relationship between Tb and the printing density.

FIG. 2 shows the structure of the drive system of the thermal head. FIG. 6 shows an example of punching timing. Stencil base paper feed drive system
When the stepping motor drive pulse PM is input to 46,
The stencil base paper is fed by one line in the sub-scanning direction. On the other hand, the data is sequentially taken into the shift register 44 at the timing of the transfer clock and is shifted to the right. After the data transfer for one line is completed, it is latched in the latch circuit 45 all at once by the LOAD signal. Thereafter, recording pulse signals (PS1 to PS4) are sequentially applied, and the heating resistors 42a to 42d are driven according to the recording data latched for the pulse width Tw, and the stencil base paper is punched. After punching for one line, the stepping motor drive pulse PM is input and the stencil base paper is fed for one line in the sub-scanning direction. The above operation is repeated.

There is a thermal head 1 in which the common electrode 1c is divided into two to substantially double the printing density. In the case of perforating the stencil base paper, the heating resistors 42 adjacent to each other in the perforated state receive the same stress as in the perforated state even if they are not in the perforated state.

Now, let's look at how the print pulse width and applied power (controlled by applied voltage) affect each quality of thermal printing and stencil plate making at the thermal head drive system of FIG. 2 and printing timing of FIG. Let's try. Of course, the perforation quality of the stencil base paper will be referred to as the print quality obtained by applying the stencil printing machine. If the printing energy is insufficient, "broken lines" will occur, and if too large, "blurring between lines" will occur. Experimental results are shown in FIGS. 13 and 14.

The experimental conditions are as follows.

1.67msec ≤ Ta = Tb ≤ 4.17msec Experimental machine; Xerox TC240 remodeling machine Output pattern; 250μ width ladder pattern Ink donor film; Xerox TC240 ink donor film (manufactured by Dai Nippon Printing) Stencil base paper; Lithograph master H-1 ( Ideal Science) Stencil printing machine; Holly Rotary 1000 (Made by Horii Shoushado) As shown in Figs. 13 and 14, the optimum range of printing conditions differs between thermal printing and stencil printing. The problem here is that the resistance value of each heating resistor of the thermal head varies (usually ± 30%), and even if the applied voltage is constant, the applied power also varies and white streaks occur on the printed image or printed image. That is. Therefore, it is necessary to reduce the influence of this variation in applied power as much as possible. To do so, select the pulse width and applied power that correspond to the center of the print quality and the range of good print quality, and switch the thermal head with each optimum pulse width or applied power during thermal printing and stencil plate making. . For example, if the applied pulse width is fixed at 1.0 msec, the applied power during thermal printing is 0.775 ± 0.125 W,
When the stencil plate making is 1.025 ± 0.125W, while the applied power is fixed to 0.9W, the applied pulse width at the time of thermal printing is about 0.5 to 1.0 msec, and when the stencil plate making is about 1.0 to 2.0 msec. Of course, both the applied power and the applied pulse width may be controlled together.

In order to obtain good print quality and punching quality, in addition to the above thermal head driving conditions, commonly known thermal head driving parameters such as punching timing and duty ratio may be controlled, or a combination of these parameters may be controlled. You can

Hereinafter, Examples 1 and 2 and Comparative Examples 1, 2 and 3 will be described in comparison.

(Example 1) The experimental conditions were as follows: Thermal head: KH106-6 (R = 340Ω, manufactured by Rohm Co.) Ink donor film: FX.TC240 (manufactured by Dai Nippon Printing Co., Ltd.) Stencil base paper: Lithograph master (manufactured by Ideal Science) Printing pattern: 250μ width ladder pattern and solid thermal head 4-division drive Printing timing: 1.67msec ≤ Ta ≤ 4.17msec 1.67msec ≤ Tb ≤ 4.17msec Print pulse width: 0.83msec (above thermal print and stencil plate making) Applied voltage: Thermal print: 18.5 V stencil plate making: 20.9V stencil printing: Holly Rotary 1000 (made by Horii Shoushado).

And 1,000 thermal prints, stencil plate making 1,0
00 sheets were alternately executed, and quality evaluation was performed on the 1,000th thermal print and the 1,000th original stencil print.

As a result, both thermal printing and stencil printing were of good quality with no breaks in the lines and no wrinkles between the lines.

(Example 2) Experimental conditions were: stencil plate making; perforation timing: 2.0 msec ≦ Ta = Tb ≦ 5.0 msec, perforation pulse width: 1.0 msec, applied voltage: 20.4V.

Other conditions were the same as those in the example.

As a result, both thermal printing and stencil printing were of good quality, with no breaks in the lines and no wrinkles between the lines.

(Comparative Example 1) Experimental conditions were stencil plate making; applied voltage: 18.5 V. Other conditions were the same as in Example 1.

The stencil print quality was markedly poor in line breaks.
The thermal print quality was good.

(Comparative Example 2) The experimental conditions were as follows: printing timing: 2.0 msec ≤ Ta = Tb ≤ 5.0 msec, printing pulse width: 1.0 msec, applied voltage: 20.4 V (above thermal printing, stencil plate making common) .

The stencil print quality was good, but the thermal print quality was significantly poor due to the formation of interline defects.

(Comparative Example 3) Experimental conditions were stencil printing; perforation timing: 0.5 msec ≦ Ta = Tb ≦ 6.5 msec. Other conditions were the same as in Example 2.

In both thermal printing and stencil printing, line thinning and white streaks, which are considered to be due to the deterioration of the heating resistor of the thermal head, occurred remarkably.

EFFECTS OF THE INVENTION According to the present invention, deterioration of the thermal head during stencil plate making is remarkably reduced, and further, for the ink donor film and the stencil base paper, it is now possible to drive the thermal head under optimum printing conditions, so that Good thermal print quality and stencil drilling quality are obtained.

Further, since thermal printing can be selected for printing a small number of copies and stencil plate making can be selected for a large number of copies by button operation, it is possible to construct a printing system with low running cost from a small number of copies to a large number of copies.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a stencil plate making apparatus which also serves as a thermal printer to which the present invention is applied, FIG. 2 is a circuit configuration diagram showing the configuration of a thermal head drive system, and FIG. 3 is a thermal head drive condition. FIG. 4 is a block diagram showing a means for changing over, FIG. 4 is an enlarged configuration view of a main part showing a state of perforation by a thermal head, FIG. 5 is an enlarged view showing a part of a heating resistor, and FIG. 6 is a thermal head. 7 is a time chart showing the print timing, FIG. 7 is a time chart showing the relationship between the stepping motor drive pulse, the stencil base paper moving speed and the print pulse. FIGS. 8 (A) and 8 (B) are the stencil master plate and the thermal transfer print. Figure 9, Figure 10, Figure 11, Figure 11 and Figure 12 are diagrams for explaining that the images in Figure are mirror images of each other. Graph showing the relationship between the grayed and stencil printing quality, Figure 13 and Figure 14 is a graph showing the relationship between the printing quality thermal head printing conditions. 1 ... Thermal head, 2 ... Platen roll, 3 ... Ink donor film, 4 ... Paper, 5 ... Stencil base paper (base paper), 12 ... Paper output tray, 16 ... Stencil base paper output tray, 18 …… Stencil base paper insertion slot, 41 …… Thermal head, 43 …… Thermal head drive circuit, 46 …… Base paper feed drive system.

Claims (2)

[Claims] 1. A stencil plate making mechanism for punching a stencil plate for stencil printing with a thermal head, and at least during stencil plate making,
The time from applying the driving pulse to the driving means for feeding the base paper to applying the perforation pulse to the thermal head
5. A stencil plate making apparatus for copying plates, characterized in that it is set to 5.83 msec or less, and the time until the stencil sheet feed drive pulse is applied after the completion of the application of the punching pulse is set to 0.83 msec or more. 2. A stencil plate making mechanism for punching a stencil plate for stencil printing with a thermal head, and at least during stencil plate making.
The time from applying the driving pulse to the driving means for feeding the base paper to applying the perforation pulse to the thermal head
It is set to 5.83 msec or less, and the time until the base paper feed drive pulse is applied after the completion of the perforation pulse application is set to 0.83 msec or more, respectively, and a thermal print mechanism for thermal printing by a thermal head is provided, and at the time of thermal printing and stencil plate making. A printing apparatus comprising means for independently setting thermal head driving conditions.