JPH07199417A - Heating method for diazo heat-sensitive sheet - Google Patents

Abstract

(57) [Summary] [Object] To provide a heating method for a diazo heat-sensitive sheet, which has a small difference in copy quality regardless of the exposure speed and which can uniformly develop a good image quality. A diazo heat sensitive sheet exposed in an exposure process is supplied between a flat heater 4 and a backup roll 3 which rotates by being pressed against the flat heater, and the diazo heat sensitive sheet driven by the frictional force of the backup roll is a flat heater. In the heating method of the diazo heat-sensitive sheet which is heat-developed while sliding on, the peripheral speed of the backup roll and the input power of the flat heater are changed according to the change of the exposure speed in the exposure step,
If the peripheral speed of the backup roll is high, raise the temperature of the flat heater.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating method for a diazo heat-sensitive sheet, which heat-develops the diazo heat-sensitive sheet exposed in the exposure step with a flat heater type heating device.

[0002]

2. Description of the Related Art A diazo copying machine forms an image by utilizing the photosensitivity and coupling reactivity of a diazonium salt, and a single-color copy with high positive contrast can be directly produced by two steps of exposure and heat development. Although it can be obtained, it has advantages of low copy cost and easy handling. In the exposure process in a diazo copying machine, the original image and the diazo photosensitive paper coated with the diazo photosensitive material are superposed, and contact transmission exposure is performed with the original image as the light source side. A transparent glass cylinder is used in which one or several tube-shaped light source lamps that radiate ultraviolet rays well are arranged. The cylinder is held by a plurality of cloth backup belts divided in the axial direction, and the cylinder rotates as the backup belt moves. Then, when the original image and the diazo photosensitive paper are superposed and the original image is placed on the cylinder side between the cylinder and the backup belt, the diazo photosensitive paper moves while being in close contact with the original image, and is exposed by the light transmitted through the original image.

The exposed diazo heat-sensitive sheet is separated from the original image and subjected to heat development. In the past, a heat-roll type heating device was mainly used for heat-developing the diazo heat-sensitive sheet. The heating device of the heat roll type has a pair of rolls including a heat roll for heating the diazo heat sensitive sheet and a backup roll for pressing the diazo heat sensitive sheet against the heat roll. Then, the diazo heat-sensitive sheet is supplied between both rotating rolls, and is heat-treated while moving in a pressure-bonded state to the heat roll. This backup roll is made of a material with a high elasticity such as silicon rubber so that the diazo heat-sensitive sheet can be pressed securely, and it is also called a soft roll. In order to improve the quality, many aluminum pipes are coated with Teflon or the like, which is also called a hard roll, and a tubular heater lamp such as a halogen bulb is arranged inside the hard roll along the axial direction.

When the required heating time is relatively short as in the case of heat fixing of a PPC or a laser printer, a predetermined heating time can be secured only by heating between a pair of rolls. In the case of heat-development, since a relatively long heating time is required, it is necessary to slow down the rotation speed of the roll, and there is a problem that the development time becomes long. In order to solve this problem, multiple backup rolls are arranged around the heat rolls, and a guide member slightly separated from the peripheral surface of the heat rolls is provided between the backup rolls to wind the diazo heat-sensitive sheet around the heat rolls. The heating time is lengthened by pressing it so that it sticks.

The hot roll method is 120 to 130 ° C.
Since it is processed at a relatively low temperature, and the heating time is long, it is possible to obtain a uniform and good copied image. However, since a heat roll having a large heat capacity is heated, there is a problem that the warm-up time is long and the power consumption is large. In order to meet the recent demand for high-speed processing, it is necessary to increase the size of heat rolls, backup rolls, etc., resulting in higher weight and higher power consumption.

For this reason, recently, a heating device using a flat heater has been attracting attention. The flat heater type heating device is composed of, for example, a flat heater in which a heating resistor is screen-printed on an alumina substrate and a backup roll that rotates in pressure contact with the flat heater. The diazo heater supplied between the flat heater and the backup roll is used. The heat sensitive sheet is driven by the frictional force of the backup roll, and the surface of the diazo heat sensitive sheet coated with the sensitive material is thermally developed while sliding on the flat heater.

The flat heater type heating device can reduce the heat capacity of the entire heating portion, so that the thermal response is good, the warm-up time is short, the structure is simple, and the size and weight can be reduced. Further, since the diazo heat-sensitive sheet can be intensively and efficiently heated, it has advantages that it can be processed at high speed and consumes less power. However, when developing the heat-developable diazo heat-sensitive sheet, a good quality copy image cannot be obtained only by heating for a short time by the flat heater, and the heat of the backup roll preheated to 140 to 180 ° C. by the flat heater is used. It was found that the diazo heat sensitive sheet also needed to be heated from the back side.

[0008]

As described above, the diazo copying machine has the exposure step and the heat development step, but the exposure speed in the exposure step, that is, the rotation speed of the cylinder needs to be largely changed depending on the quality of the original paper. , For example PPC
There is about twice the difference between paper and tracing paper. On the other hand, the development time in the heat development process is not related to the quality of the original paper, but when the cylinder in the exposure process and the backup roll in the heat development process are rotationally driven by one drive motor, the peripheral speed of the backup roll increases as the exposure time increases. Will be slowed accordingly. Therefore, when the exposure time is long, the thermal development time also becomes long and overdevelopment occurs, and the image becomes white and the whitening phenomenon occurs. On the contrary, when the exposure time is short, the development time becomes short and the development becomes insufficient. However, there is a problem that the color is not sufficiently developed.

Therefore, if the two driving motors rotate the cylinder for the exposure process and the backup roll for the heat development process individually to keep the peripheral speed of the backup roll constant regardless of the exposure speed, the above problems are solved. However, the number of parts increases, the weight increases, and the cost increases. Also, even if the exposure time is short, it takes a certain amount of time to develop, so
Since it is difficult to reduce the total copying time, it is not realistic to separately rotate and rotate the cylinder for the exposure process and the backup roll for the heat development process with the two drive motors.

Therefore, an object of the present invention is to provide a heating method for a diazo heat-sensitive sheet which has a small difference in copy quality irrespective of the exposure speed and is capable of uniformly coloring to obtain a good image quality.

[0011]

In order to achieve the above object, the present invention supplies a diazo heat-sensitive sheet exposed in an exposure step between a flat heater and a backup roll which rotates in pressure contact with the flat heater. In the heating method of the diazo heat sensitive sheet which is developed by sliding the diazo heat sensitive sheet driven by the frictional force of the backup roll on the flat heater, the peripheral speed of the backup roll and the input power of the flat heater are set to the exposure speed of the exposure process. When the peripheral speed of the backup roll is high, the temperature of the flat heater is increased according to the change.

[0012]

That is, when the exposure time is short and the peripheral speed of the backup roll is high, the temperature of the flat heater is high. On the contrary, when the exposure time is long and the peripheral speed of the backup roll is low, the temperature of the flat heater is high. Since the heat treatment is performed at a low temperature, that is, at a temperature according to the heat treatment time, proper heat development is possible regardless of the exposure speed, and the difference in copy quality is reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the embodiments shown in the drawings. FIG. 1 shows a heat-developing diazo copying machine. In FIG. 1, a casing 1 injection-molded with a synthetic resin has an inverted W-shape in which the upper part has two peaks 11 and 12 arranged side by side. There is an exposure device A in Maeyama 11
A heat developing device B, which is the heating device of the present invention, is housed in the rear mountain 12. The front slope 11a of the front mountain 11 is provided with an exposure inlet 13 for supplying the diazo photosensitive paper coated with the diazo sensitive material and the original drawing to the exposure apparatus A, and an exposure outlet 14 discharged after the exposure. Further, a development inlet 15 for separating the exposed diazo photosensitive paper from the original drawing and supplying it to the heat developing apparatus B is provided at the lower end portion of the front slope 12a of the rear mountain 12 and the diazo photosensitive paper after the heat development is completed. A developing outlet 16 through which the toner is discharged is provided on the rear slope 12b of the rear mountain 12. A bottom plate 17 is attached to the lower surface of the casing 1 and accommodates drive motors (not shown) and electrical components constituting various control units, etc., inside the bottom plate 17.

In the exposure apparatus A, a cylinder 21 made of transparent Pyrex glass is rotatably arranged, inside of which a rating of 100 W and a wavelength of 4 is provided along the axis.
One tube-shaped fluorescent lamp 22 that strongly emits 20 nm light is arranged. And four idle rolls 23 and 1
An endless backup belt 25 is wound around the drive roll 24 and the cylinder 21 of the book,
This backup belt 25 holds the cylinder 21. Then, the roll 2 is driven by a motor (not shown).
When 4 is driven and rotated, cylinder 21 rotates with backup belt 25 in the direction of the arrow.

Next, as a heating portion of the heat developing device B, a flat heater type heating device including a flat heater 4 and a backup roll 3 rotating in pressure contact with the flat heater 4 is arranged. The arc-shaped carry-in guide 5 and the discharge guide 6 are arranged along the outer peripheral surface of the backup roll 3, and the discharge roll 71 and the discharge plate 72 are provided downstream of the discharge guide 6.
Are arranged. Then, the cylinder 21 of the exposure apparatus
The backup roll 3 and the discharge roll 71 rotate in the direction of the arrow by the same motor that rotates and drives the. Therefore, if the rotation speed of the cylinder 21 changes,
The peripheral speed of the backup roll 3 also changes accordingly. Further, the temperature sensor 8 comes into contact with the backup roll 3 so that the temperature of the backup roll 3 can be detected.

The structure of the flat heater 4 will be described with reference to FIG. 2. The surface of the alumina substrate 41 having a width of 10 mm has a width of 3 m.
A heating resistor 42 of m is screen-printed, and its surface is covered with an overcoat layer 43. The alumina substrate 41 is held by a heat-resistant resin material 44 for preventing heat of the heat-generating resistor 42 from escaping to other than the pressure-contacting portion, and the heat-resistant resin material 44 has rigidity to withstand the pressure-contacting force of the backup roll 3 or the like. It is fixed to the support frame 45. Although the rated power of the heating resistor 42 is 1200 W, a thermistor (not shown) detects the temperature of the flat heater 4 and controls it to a predetermined temperature by phase control. And
Since the flat heater 4 has a small heat capacity, it has good thermal responsiveness, and the set temperature of the flat heater 4 can be changed in an extremely short time by changing the input power.

Next, the backup roll 3 has an outer diameter of 4
It is a long roll with a diameter of 0 mm and a length of 700 mm, but an intermediate layer 33 made of foam sponge with a thickness of 8.5 mm is arranged on the outer circumference of a stainless steel core pipe 31, and the intermediate layer 33 has a thickness of 2 mm. Solid layer of skin made of silicone rubber 3
Covered with 2.

Then, the power switch (not shown) is turned on.
When the heating resistor 42 is energized and the backup roll 3 is rotated, the backup roll 3 is heated by the flat heater 4 after the warm-up time has elapsed, but when the backup roll 3 rises to a predetermined temperature and copying becomes possible, copying is performed. OK
Is displayed. After that, the diazo photosensitive paper coated with the diazo photosensitive material and the original image are overlaid and inserted from the exposure inlet 13, and the backup belt 25 causes the cylinder 2
The light of the fluorescent lamp 22 which is pressed against 1 and moves through the cylinder 21 in this process passes through the original image to expose the photosensitive paper, but the rotation speed of the cylinder 21 changes according to the quality of the original paper. Then, the exposed photosensitive paper is the exposure exit
Emitted from 14.

Next, when the diazo photosensitive paper which is the diazo heat sensitive sheet is separated from the original drawing and supplied from the developing inlet 15, the diazo photosensitive paper P is guided to the carry-in guide 5 and the backup roll 3 as shown in FIG. And the flat heater 4. Then, the diazo photosensitive paper P is driven by the frictional force of the backup roll 3, slides in a state of being in pressure contact with the high temperature flat heater 4, is heated by the flat heater 4 and the preheated backup roll 3, and is thermally developed, Color is developed according to the original drawing.

Since the backup roll 3 is rotationally driven by the motor that rotationally drives the cylinder 21, the peripheral speed of the backup roll 3 changes according to the rotational speed of the cylinder 21. That is, the heat development time changes according to the exposure time. Therefore, in the present invention, the set electric power is changed by changing the electric power supplied to the flat heater 4 according to the peripheral speed of the backup roll 3. Table 1 shows a specific example.

[0021]

[Table 1]

As described above, when the exposure time is short and the peripheral speed of the backup roll 3 is fast, the heat treatment time is short. Therefore, the input power is increased to increase the set temperature of the flat heater 4, and the exposure time is long. When the peripheral speed of the backup roll 3 is slow, the heat treatment time is long, so the applied power is reduced and the set temperature of the flat heater 4 is lowered. Therefore, the excessive development and the insufficient development due to the change in the peripheral speed of the backup roll 3 are eliminated, and a constant copy quality can be obtained.

[0023]

As described above, in the method for heating a diazo heat-sensitive sheet of the present invention, the peripheral speed of the backup roll and the electric power supplied to the flat heater are changed according to the change of the exposure speed in the exposure step to change the backup roll. When the peripheral speed is high, the temperature of the flat heater is raised, so there is little difference in copy quality regardless of the exposure speed, and a method for heating a diazo heat-sensitive sheet that is capable of uniform color development and good image quality is provided. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a heat development type diazo copying machine.

FIG. 2 is a sectional view of a main part of a heat development type diazo copying machine.

[Explanation of symbols]

 1 Casing 21 Cylinder 22 Fluorescent Lamp 3 Backup Roll 31 Core Pipe 32 Solid Layer 33 Intermediate Layer 4 Flat Heater 5 Carrying Guide 6 Discharge Guide

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Shigeo Kijima 262 Kondo, Tatebayashi, Gunma Gunma Ushio Electric Co., Ltd. 72) Inventor Taro Hayashi, 262 Kondo, Tatebayashi City, Gunma Prefecture Gunma Ushio Electric Co., Ltd. (72) Inventor, Hiroshi Shimizu 262, Kondo, Tatebayashi City Gunma Prefecture, Gunma Ushio Electric Co., Ltd. 2-26-30 Nishi-Azabu, Minato-ku Fuji Shashin Film Co., Ltd.

Claims (1)

[Claims] 1. A diazo heat-sensitive sheet exposed in the exposure step is supplied between a flat heater and a backup roll that is rotated in pressure contact with the flat heater, and a diazo heat-sensitive sheet driven by the frictional force of the backup roll. A method for heating a diazo heat-sensitive sheet, which comprises performing thermal development while sliding on a flat heater, wherein the peripheral speed of the backup roll and the electric power supplied to the flat heater are changed according to the change of the exposure speed in the exposure step, and the circumference of the backup roll is changed. A method for heating a diazo heat-sensitive sheet, which comprises raising the temperature of a flat heater when the speed is high.