JP2948082B2 - Heating method of diazo thermal sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a method for heating a diazo thermosensitive sheet in which a diazo thermosensitive sheet having one surface of a sheet-shaped carrier coated with a diazo sensitive material is thermally developed by 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 having a high positive contrast is directly obtained in two steps of exposure and heat development. Although it can be obtained, it has the advantages of low copy cost and easy handling. In the exposure step in a diazo copying machine, an original drawing and a diazo photosensitive paper coated with a diazo photosensitive material are superimposed, and close contact transmission exposure is performed with the original drawing as a light source side. A transparent glass cylinder in which one or several tube-shaped light source lamps that emit ultraviolet light well is used. The cylinder is held by a plurality of axially divided cloth backup belts, and the cylinder rotates as the backup belt moves. Then, when the original drawing and the diazo photosensitive paper are overlapped and the original drawing is placed between the cylinder and the backup belt with the original drawing on the cylinder side, the diazo photosensitive paper moves while being in close contact with the original drawing, and is exposed by light transmitted through the original drawing.

[0003] The exposed diazo thermosensitive sheet is subjected to thermal development separately from the original drawing. Conventionally, in order to thermally develop the diazo thermosensitive sheet, a heating device of a heat roll type has been mainly used. The heating device of the heat roll type has a pair of rolls of a heat roll for heating the diazo thermosensitive sheet and a backup roll for pressing the diazo thermosensitive sheet against the heat roll. Then, the diazo thermosensitive sheet is supplied between the two rotating rolls, and is heated while moving in a press-fit state on the heat roll. The backup roll is made of an elastic material such as silicon rubber and the surface is also called a soft roll so that the diazo heat-sensitive sheet can be pressed securely. In order to improve the quality, the surface of an aluminum pipe is often coated with Teflon or the like, and is also called a hard roll, in which a tubular heater lamp such as a halogen bulb is arranged along the axial direction.

In the case where the required heating time is relatively short, as in the case of heat fixing such as a PPC or a laser printer, a predetermined heating time can be secured only by heating between a pair of rolls. When heat development is performed, a relatively long heating time is required, so that 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, a plurality of backup rolls are arranged around the heat roll, a guide member is provided between the backup rolls and slightly separated from the peripheral surface of the heat roll, and the diazo thermosensitive sheet is wound around the heat roll. The heating time is lengthened by pressure contact so as to stick.

[0005] Such a hot roll system is used at 120 to 130 ° C.
Since the processing is performed at a relatively low temperature and the heating time can be extended, a uniform and good copy image can be obtained. However, there is a problem that a warm-up time is long and power consumption is large because a heat roll or the like having a large heat capacity is heated. In order to respond to recent demands for high-speed processing, it is necessary to increase the size of a heat roll, a backup roll, and the like, which results in an increase in weight and power consumption.

For this reason, a heating apparatus using a flat heater has recently been receiving attention. The heating device of the flat heater type comprises, for example, a flat heater in which a heating resistor is screen-printed on an alumina substrate and a backup roll which rotates while being pressed against the flat heater, and a diazo supplied between the flat heater and the backup roll. 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 light-sensitive material is heated while sliding on the flat heater.

[0007] The heating device of the flat heater system can reduce the heat capacity of the entire heating section, so that the warm-up time is shortened, the structure is simple, and the size and weight can be reduced. In addition, since the diazo heat-sensitive sheet can be intensively and efficiently heated, high-speed processing can be performed and power consumption is low.

[0008]

As described above, the heating time of the flat heater type heating device is shorter than that of the hot roll type heating device.
Although it is a high temperature of about ° C., the diazo thermosensitive sheet contacts the flat heater only for about 1/10 of the heating device of the hot roll type. When developing a heat-developing diazo thermosensitive sheet, a high-quality copy image cannot be obtained only by heating for a short time with a flat heater.
It was found that it was necessary to heat the diazo thermosensitive sheet also from the back side by the heat of the backup roll preheated to 40 to 180 ° C.

As shown in FIG. 4, the diazo thermosensitive sheet P has a sheet-shaped carrier 91 such as paper or film coated with a diazo sensitive material 92 on one surface thereof. Exists. Accordingly, the diazo photosensitive material 92 also has irregularities and has peaks and valleys. However, when thermal development is performed in a short time by a flat heater type heating device, when the temperature of the flat heater is relatively low and the amount of heat is insufficient. Means that the peaks that reliably contact the flat heater develop sufficient color, but the heat does not satisfactorily reach the valley where the contact with the flat heater is insufficient.
Insufficient color development causes partial underdevelopment. On the other hand, if the amount of heat is increased by increasing the temperature of the flat heater, the valleys will develop sufficient color, but the hills will be overheated and the diazo sensitive material will decompose and become white, resulting in insufficient density. That is, in any case, even if the surface on which the diazo photosensitive material is applied is heated in a short time by the flat heater, the coloring ability of the diazo photosensitive material cannot be sufficiently brought out, and the coloring unevenness is likely to occur. There is a problem that image quality cannot be obtained.

Accordingly, an object of the present invention is to provide a method for heating a diazo heat-sensitive sheet capable of uniformly forming a color without causing color unevenness and obtaining good image quality.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a diazo heat-sensitive sheet having a sheet-shaped carrier coated with a diazo light-sensitive material on one surface thereof, which is pressed against the flat heater and rotated. In a method of heating a diazo thermosensitive sheet, which is supplied between backup rolls to be heated and thermally developed while sliding the diazo thermosensitive sheet driven by the frictional force of the backup roll with a flat heater, the diazo thermosensitive material of the diazo thermosensitive sheet is applied. The developed surface is brought into contact with a backup roll and thermally developed.

[0012]

The surface of the diazo thermosensitive sheet coated with the diazo sensitive material (front surface) is brought into contact with a low-temperature backup roll, and the surface of the diazo thermosensitive sheet not coated with the diazo sensitive material (back surface) is brought into contact with a high-temperature flat heater. Since heat development is performed, high-temperature heat from the flat heater is transmitted to the diazo photosensitive material through the carrier. Therefore, even if the temperature of the flat heater is increased, the manner in which heat is transmitted becomes gentle, the amount of heat transmitted to the peaks and valleys of the photosensitive material is balanced, and a uniform color is formed to obtain a high-quality copy image.

[0013]

DETAILED 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 is formed by arranging two ridges, a front ridge 11 and a rear ridge 12. Exposure device A is located in Maeyama 11
In the rear mountain 12, a thermal developing device B, which is the heating device of the present invention, is accommodated. On the front slope 11a of the front mountain 11, there are provided an exposure inlet 13 for superposing the diazo photosensitive paper coated with the diazo sensitive material on the original drawing and supplying it to the exposure apparatus A, and an exposure outlet 14 for discharging after the exposure. Further, a developing inlet 15 for separating the exposed diazo photosensitive paper from the original drawing and supplying it to the thermal developing device B is provided at a lower end portion of the front slope 12a of the rear mountain 12, and the diazo photosensitive paper on which the thermal development is completed is provided. A developing outlet 16 is provided on the rear slope 12b of the rear mountain 12 to discharge the developer. A bottom plate 17 is attached to the lower surface of the casing 1, and a drive motor (not shown) and electrical components constituting various control units are accommodated in the bottom plate 17.

In the exposure apparatus A, a cylinder 21 made of transparent Pyrex glass is freely rotatable, and has a rating of 100 W along an axis and a wavelength of 4 W inside the cylinder 21.
One tube-shaped fluorescent lamp 22 that strongly emits 20 nm light is provided. And 4 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. The drive roll 2 is driven by a motor (not shown).
When 4 is driven to rotate, the cylinder 21 rotates together with the backup belt 25 in the direction of the arrow.

Next, as a heating section of the heat developing device B, a heating device including a flat heater 4 and a backup roll 3 which rotates while being pressed against the flat heater 4 is arranged. An arcuate carry-in guide 5 and a discharge guide 6 are arranged along the outer peripheral surface of the backup roll 3, and a discharge roll 71 and a discharge plate 72 are arranged downstream of the discharge guide 6. Then, the backup roll 3 and the discharge roll 71 are rotated in the direction of the arrow by a motor (not shown). Also, the temperature sensor 8 comes into contact with the backup roll 3,
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 width of the alumina substrate 41 having a width of 10 mm is 3 m.
The m heating resistor 42 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 the heat of the heat-generating resistor 42 from escaping to a portion other than the pressure contact portion. The heat-resistant resin material 44 has a rigidity to withstand the pressure contact force of the backup roll 3. 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.

Next, the backup roll 3 has an outer diameter of 4 mm.
The roll is a long roll having a length of 0 mmφ and a length of 700 mm. An intermediate layer 33 made of a foamed sponge having a thickness of 8.5 mm is disposed around the outer periphery of a stainless steel core pipe 31. The intermediate layer 33 has a thickness of 2 mm. Solid layer of skin made of silicone rubber 3
Covered with 2

When the power switch (not shown) is
N, 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 elapse of the warm-up time. OK
Is displayed. After that, the diazo photosensitive paper coated with the diazo photosensitive material is superimposed on the original drawing and inserted from the exposure entrance 13.
The light from the fluorescent lamp 22 that has passed through the cylinder 21 passes through the original drawing to expose the photosensitive paper and is discharged from the exposure outlet 14 in this process.

Next, when the diazo photosensitive paper, which is a diazo thermosensitive sheet, is separated from the original drawing and supplied from the development inlet 15, the diazo photosensitive paper P is guided to the carry-in guide 5 as shown in FIG. And the flat heater 4. The diazo photosensitive paper P is driven by the frictional force of the backup roll 3, slides in a state of being pressed against the high-temperature flat heater 4, is heated by the flat heater 4 and the preheated backup roll 3, and is thermally developed. Color develops as per the original drawing.

Here, as shown in FIG. 3, the surface (surface) of the diazo heat-sensitive sheet P on which the diazo light-sensitive material 92 is applied contacts the backup roll 3 having a low temperature, and the diazo heat-sensitive material 9
2 A flat heater 4 with a high temperature on the side not coated (back side)
Heat development in contact with Therefore, since the high-temperature heat from the flat heater 4 is transmitted to the diazo sensitive material 92 through the carrier 91, even when the flat heater 4 is heated to a high temperature, the heat is transmitted slowly, and the heat is transferred to the peaks and valleys of the diazo sensitive material 92. The amount of transmitted heat is balanced, and the color is uniformly developed to obtain a high quality copy image. Further, since the diazo sensitive material 92 does not slide on the surface of the flat heater 4, there is an advantage that the flat heater 4 and the diazo sensitive material 92 are not easily damaged. As described above, in the present invention, since the heat of the flat heater 4 is transmitted to the diazo sensitive material 92 through the carrier 91, the temperature of the flat heater 4 and therefore the temperature of the backup roll 3 also need to be raised somewhat. When the peripheral speed of the heater is 70 mm / s, the flat heater 4
Is preferably 220 to 230 ° C., and the temperature of the backup roll 3 is preferably about 160 to 170 ° C.

[0021]

As described above, in the method for heating a diazo thermosensitive sheet according to the present invention, the surface of the diazo thermosensitive sheet coated with the diazo sensitive material is brought into contact with the backup roll, and the heat of the flat heater is passed through the carrier. Since the heat is transferred to the material and heat-developed, the color-forming ability of the diazo-sensitive material can be sufficiently drawn out, and there is no unevenness in the coloration, and a method for heating the diazo-sensitive sheet that can uniformly develop colors and obtain good image quality. can do.

[Brief description of the drawings]

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

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

FIG. 3 is an explanatory diagram of an embodiment of the present invention.

FIG. 4 is an explanatory view of a diazo thermosensitive sheet.

[Explanation of symbols]

 DESCRIPTION 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 Carry-in guide 6 Discharge guide 91 Carrier 92 Diazo sensitive material P Diazo thermal sheet

Continued on the front page (72) Inventor Hiroyuki Kushida 262 Kondo, Tatebayashi-shi, Gunma Prefecture Inside Gunma Ushio Electric Co., Ltd. (72) Inventor Taro Hayashi 262 Kondo, Tatebayashi-shi, Gunma Prefecture Inside Ushio Gunma Electric Co., Ltd. (72) Inventor Shimizu Yo, 262 Kondo, Tatebayashi-shi, Gunma Gunma Ushio Electric Co., Ltd. (72) Yasushi Yao Inventor 2-26-30 Nishiazabu, Minato-ku, Tokyo Fuji Photo Film Co., Ltd. (56) References JP-A-4-366840 (Japanese) JP, A) JP-A 1-172047 (JP, U) JP-A 1-172046 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03D 13/00 G03C 5/18

Claims (1)

(57) [Claims] 1. A diazo thermosensitive sheet in which a diazo sensitive material is applied to one surface of a sheet-shaped carrier is supplied between a flat heater and a backup roll which is pressed against the flat heater and rotates, and a frictional force of the backup roll is provided. A method of heating a diazo thermosensitive sheet, wherein the diazo thermosensitive sheet is driven by a flat heater to thermally develop the diazo thermosensitive sheet, wherein the surface of the diazo thermosensitive sheet coated with the diazo sensitive material is contacted with a backup roll to perform thermal development. A method for heating a diazo thermosensitive sheet.