JPS63178235A - Heat-developing method - Google Patents

Abstract

PURPOSE:To suppress a temperature applied to a photosensitive material to a prescribed temperature so that a uniform development can be executed, by compensating a temperature fall on the surface of a heating drum due to the low temperature part of an endless belt at the time of starting image recording, by raising the set temperature of the heating drum. CONSTITUTION:As soon as the rotation of a heating drum 14 and the endless bet 16 is started simultaneously with a start of image recording, the set temperature of a heating drum 14 is raised to a temperature (raised temperature) higher than a prescribed developing temperature, and the temperature fall of the surface of the heating drum 14 due to low temperature part of the endless belt 16. Subsequently, the heating drum 14 rotates and after the time to the extent that the low temperature part of the endless belt 16 is brought into contact entirely with the heating drum 14 is lapsed, the set temperature is returned to a prescribed developing temperature 140 deg. by a timer, or the set temperature is lowered after detecting a fact that the surface temperature of the heating drum 14 is 140+1.5 deg.C, and a regular heat development is executed. In such a way, the temperature fall of the surface of the heating drum is compensated, and a sufficient developing heating value can be given to a photosensitive material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat development method in which a photosensitive material is imagewise exposed and then heat developed by sandwiching the photosensitive material between a heating drum and an endless belt.

[Technical background of the invention and its problems]

As an example of an image recording material using microcapsules encapsulating a photosensitive composition, for example, Japanese Patent Application Laid-Open No. 57-1798
A system is known in which a synthetic polymer resin wall capsule containing a vinyl compound, a photopolymerization initiator, and a colorant precursor is supported on a support, as disclosed in Japanese Patent No. 36. The image recording method using this system is to imagewise harden the microcapsules by exposure to light, destroy the unhardened microcapsules by applying pressure, and obtain a color image from the released colorant precursor. The method is characterized in that high quality images can be obtained through simple dry processing. However, this system has the drawback of significantly lower photosensitivity than systems using silver halide.

It improves these defects and has high photosensitivity.

A novel recording material capable of obtaining high quality images through simple dry processing is disclosed in Japanese Patent Application No. 117089/1989 1F filed by the present applicant. This recording material is a photosensitive and pressure-sensitive thermal development material, in which at least a photosensitive silver halide, a reducing agent, a polymerizable compound, and a color image forming substance are coated on a support, and at least the polymerizable compound and the color image forming substance are coated on a support. The color imaging material consists of a photosensitive composition encapsulated in identical microcapsules.

Regarding the image recording method of recording an image using this light-sensitive pressure-sensitive heat-developable material, please refer to the patent application No. 6 filed by the present applicant.
0-121284. This image recording method first performs imagewise exposure to form a latent image, and then develops it by heating.

The polymerizable compound in the area where the latent image is present is polymerized to produce a high molecular compound, thereby hardening the microcapsule. Then, it is overlapped with an image-receiving material having an image-receiving layer to which the color image-forming substance can be transferred and pressurized to destroy at least a portion of the microcapsules in the areas where no latent image exists, and the color image-forming substance is transferred to the image-receiving material. to obtain an image on an image-receiving material.

Then, using the above-mentioned photosensitive material, this photosensitive material is subjected to imagewise exposure, heat development is performed, and then the image recording material is overlaid with an image-receiving material and pressed, and an image is obtained on the image-receiving material by transfer, which is automatically performed. The device is disclosed, for example, in Japanese Patent Application No. 51896/1989 filed by the present applicant.

In order to perform the above-mentioned heat development, a heating drum having a heater inside and an endless belt wound around the drum are rotated, the photosensitive material is sandwiched between the heating drum and the endless belt, heat development is performed, and then an image is received. A heat development method and apparatus have been proposed in which heat development is delivered to the overlapping portion with the material.

In this heat development method and apparatus, the heating drum and the endless belt rotate simultaneously to sandwich the photosensitive material, so that stable conveyance is achieved.

During image recording, when the heating drum and endless belt stop rotating, the heating drum is controlled to a constant temperature, so the part of the endless belt that is in contact with the heating drum surface is also controlled to a constant temperature. , since the parts that are not in contact are not subject to temperature control, the temperature gradually decreases.

When the heating drum and endless belt are rotated to develop the photosensitive material, the low-temperature part of the endless belt comes into contact with the heating drum surface and cools the drum surface, causing the drum surface temperature to drop by about 6°C from the predetermined temperature. Put it away. At this time, when the photosensitive material is sandwiched and developed, the allowable range of development temperature change for the photosensitive material is approximately ±2°C.
The photosensitive material is not heated uniformly, and development delays occur in areas where the amount of developing heat is insufficient, and the color density in these areas becomes higher than it should be, resulting in unevenness in one image.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a heat development method that can compensate for the temperature drop on the surface of a heating drum and provide a sufficient amount of heat for development to a photosensitive material.

Means for Solving Problem C] The method of the present invention achieves the above-mentioned purpose by a heat developing method in which after imagewise exposure of a photosensitive material, the photosensitive material is sandwiched between a heating drum and an endless belt to perform heat development. This is achieved by setting the temperature of the heating drum higher than a predetermined developing temperature at the same time as the start of image recording.

That is, at the same time as the heating drum rotates, the temperature of the heating drum is made slightly higher than a predetermined value to compensate for the heating drum surface humidity that is lowered by the section of the endless belt that is lower than the predetermined temperature and that is not in contact with the heating drum, and the entire endless belt is heated. After a period of time long enough for the temperature to become constant, the heating drum is gradually stabilized at a predetermined developing temperature.

In the present invention, the photosensitive material may be a material for obtaining a visible image by applying pressure to a latent image generated by imagewise exposure.

In this case, it may include a step of preliminary heat development or wet development before applying pressure.

An example of such a material is a type of material in which a polymerizable compound is imagewise cured by imagewise exposure and then a visible image is obtained by applying pressure, as disclosed in Japanese Patent Application Laid-Open No. 57/1999 filed by the present applicant. Examples include the material disclosed in Japanese Patent No. 179836. This material has a synthetic polymer resin wall capsule containing a vinyl compound, a photopolymerization initiator, and a colorant precursor supported on a support.

Alternatively, after containing silver halide and giving imagewise exposure, heat development is performed to develop the silver halide, the polymerizable compound is simultaneously cured in correspondence with this development, and then pressure is applied to form a visible image. One example of the type of material that can be obtained is the material disclosed in Japanese Patent Application No. 121284/1984 filed by the present applicant. The material disclosed in Japanese Patent Application No. 121284/1984 is a material that is thermally developed and then transferred to an image-receiving material having an image-receiving layer to obtain an image on the image-receiving material.

At least a photosensitive silver halide, a reducing agent, a polymerizable compound, and a color image-forming substance are coated on a support, and at least the polymerizable compound and the color image-forming substance are encapsulated in the same microcapsule. It is something that exists.

[Embodiment]

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

FIG. 1 is a sectional view of an image recording apparatus in which the method of the present invention is implemented.

A transparent supporting glass plate 2 on which a document is placed is provided on two sides of the housing 1, and an exposure device 3 is provided below the glass plate 2.
It is equipped with The exposure device 3 is fixed in the housing 1, and the glass plate 2 is reciprocated in the horizontal direction indicated by arrow A above the exposure section [3] by a driving means (not shown).

The photosensitive material S is wound into a roll and stored in the magazine 4, and is pulled out from the magazine 4 by a pair of feed rolls 5. The magazine 4 is attached and detached after the upper cover 37 is rotated around its right end and opened. An image recording start signal is input by an operation button (not shown), and the photosensitive material S pulled out from the magazine 4 is transported to the exposure section by the transport rolls 7, 8, 9, and cut into a predetermined length by the cutter 6 while being exposed. disconnected.

The photosensitive material S having the exposed image and cut into sheets is then transferred to a heat developing device by conveyor rolls 10 and 11! 12.

The heat developing device 12 includes a hollow cylindrical heating drum 14, four belt support rolls 15, and a belt extending over the support rolls 15 in a heat insulating housing 13, and extends around the outer periphery of the heating drum 14 at an angle of approximately 240'. Wrapped endless belt 1
6, the photosensitive material S is transferred to the belt 16 and the heating drum 14.
The surface temperature of the heating drum 14 is detected by the temperature detector 60, and the temperature is determined by the temperature sensor 60. Halogen lamp 1 for stability
It controls 7.

The housing 13 is heated and developed by the heat developing device 12.
The photosensitive material S discharged from the photosensitive material S is transported by a transport roll 18 to a superimposing section 19, where it is overlapped with an image receiving paper C fed from an image receiving paper cassette 20 or a manual feed section 21, and is transported to a pressure transfer device 22.

The pressure transfer device 22 includes a pair of pressure rolls 23 that are in pressure contact with each other,
It consists of a backup roll 24 that is in pressure contact with each pressure roll 23, and a blade 72 for preventing wrinkles in the photosensitive material S and image-receiving paper C is provided at the entrance part, and its tip is elastically attached to the pressure roll 23. are in contact with each other. The superimposed photosensitive material S and image receiving paper C are pressed at a pressure of about 550 kg/tyi. Then, the image recorded on the photosensitive material S is transferred to the image receiving paper C.

The superimposed photosensitive material S and image receiving paper C are conveyed to a peeling device 25.

The peeling device 25 consists of a conveyance roll 26 and a peeling claw 27, and when the peeling claw 27 swings downstream of the conveyance roll 26, its tip enters between the photosensitive material S and the image-receiving paper C and peels them off. .

The photosensitive material S peeled off from the image receiving paper C by the peeling device 25 is conveyed to the waste tray 31 by conveyance rolls 28, 29, 30, discarded, and stored.

On the other hand, after the image-receiving paper C to which the image has been transferred is peeled off from the photosensitive material S, it is conveyed to the fixing device 33 by the conveyance roll 32. Then, the image-receiving paper C is irradiated with ultraviolet rays by, for example, an ultraviolet lamp 34 provided in the fixing device 33 to fix the image thereon, and is sent onto a take-out tray 36 by a transport roll 35. If the conveyance of the photosensitive material S to the waste tray 31 is completed and a signal to start recording the first image has not been input, driving of the line including the developing bag rI112 is stopped.

Therefore, when image recording is not performed in the heat developing device 12 described above, the rotation of the heating drum 14 and the endless belt 16 is stopped. Simultaneously with the start of image recording, the rotation of the heating drum 14 and the endless belt 16 is started, and at the same time the temperature is higher than the predetermined developing temperature (heating temperature).
The set temperature of the heating drum 14 is raised to compensate for the temperature drop on the surface of the heating drum 14 due to the low temperature portion of the endless belt 16. Next, after the heating drum 14 rotates for a period of time such that all the low-temperature parts of the endless belt 16 come into contact with the heating drum 14, a timer is set to a predetermined developing temperature.
Either return the set temperature to 0° or the temperature sensor 60
After detecting that the surface temperature of the heating drum 14 is 140 + 1.5°C, the set temperature is lowered and normal heat development is performed.

Further, in this embodiment, the stop time for one image recording, that is, the conveyance of the photosensitive material S to the waste tray 31 is completed.

It has a control device (not shown) that is equipped with a means for measuring the time until a signal for starting the next image recording is input, and controls the heating temperature setting to be performed only when this time is longer than a certain time.

In this embodiment, the following heating drum and endless belt are used.

Heating drum; diameter...75m+a wall thickness...61
Material: Aluminum endless belt: Thickness: 1 inch Circumference: 52
5+am Material: Fluororubber When the above-mentioned heating drum and endless belt are used, the optimum heating temperature is 142°C. This heating temperature is mainly determined by the heat capacity ratio of the heating drum 14 and the endless belt 16. The larger the heat capacity of the heating drum 14 is than the heat capacity of the endless belt 16, the smaller the difference between the heating temperature and the predetermined temperature becomes. However, if the heat capacity of the heating drum 14 becomes too large, the temperature decreases slowly, making precise temperature control difficult.
The method of the present invention is effective until the heat capacity of the heating drum 14 is about 8 times that of the endless belt 16, and is possible up to about 200 times. If the heat capacity of the heating drum 14 is smaller than the heat capacity of the endless belt, finer temperature control becomes possible and the method of the present invention becomes even more effective.

〔Effect of the invention〕

At the start of image recording, the temperature applied to the photosensitive material can be kept within ±2°C of the predetermined temperature by increasing the set temperature of the heating drum to compensate for the temperature drop on the surface of the heating drum caused by the low temperature part of the endless belt. , there is no shortage of heat for development, and uniform development is performed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an image recording apparatus to which the method of the present invention is applied. Reference numeral in the figure 1...Housing 2...Glass plate 3...
・Exposure device 4...Magazine 5...Feeding roll 6...Cutter 7, 8.9.10.1
1... Conveyance roll 12... Heat developing device 1
3...Housing 14...Heating drum 1
5... Belt support roll 16... Endless belt 17... Halogen lamp 18... Conveyance roll
19... Overlapping section 20... Image receiving paper cassette 21... Manual feed section 22... Pressure transfer device 23... Pressure roll 24... Backup roll 25... Peeling device 26...・Transport roll
27... Peeling claws 28, 29. 30... Conveyance roll 31... Waste tray 32... Conveyance roll
33... Fixing device 34... Ultraviolet lamp
35... Conveyance roll 36... Take-out tray
37...Top cover 60...Temperature detector
61... Peeling nails (and 3 others) Pa

Claims (1)

[Claims] 1) A heat development method in which after imagewise exposure of a photosensitive material, heat development is performed by sandwiching the photosensitive material between a heating drum and an endless belt, wherein the temperature of the heating drum is changed to a predetermined development temperature at the same time as the start of image recording. A heat development method characterized by setting the temperature higher.