JPS62201433A - Method and device for heat development to improve uneven transfer - Google Patents

Abstract

PURPOSE:To improve uneven transfer by the use of a diffusion transfer type heat development photosensitive element and image receiving element by providing a preliminary heating stage for the image receiving element to the stage before a stage for superposing the photosensitive element and the image receiving element. CONSTITUTION:The roll-shaped heat development photosensitive element 1 is guided by a guide roller 2 to an exposing position where the element is exposed with an image by a CRT 3. On the other hand, the image receiving element 5 is preliminarily heated by a flat plate-shaped heater 4 in the stage before the element is superposed on the exposed photosensitive element 1. The preliminarily heated image receiving element 5 and the photosensitive element 1 are superposed by a pair of heating rollers 6, 7 and are guided by a guide plate 8 into a heat development transfer part where the elements are held in place between two upper and lower endless belts 9 and 10 and are conveyed in the state of maintaining the tight contact with each other. The heat development is executed in this state and at the same time the transfer of the dye image which is made movable to the image receiving element 5 is executed. The elements are then delivered from the endless belts. Moisture is decreased by the preliminary heating of the image receiving element in the above-mentioned manner, by which the good-quality dye image having no uneven transfer is formed on the image receiving layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a heat development method for forming a color image by improving transfer unevenness by heat development and heat transfer using a diffusion transfer type heat-developable photosensitive element and an image receiving element. and a heat developing device.

[Behind the invention! ] A diffusion transfer type heat-developable photosensitive element, in which a color image is obtained by separating a silver image and a dye by releasing a diffusible dye by heat development and transferring this dye to an image-receiving element, is disclosed in, for example, JP-A-59 -124339, 59-18134
No. 5, No. 59-159159, No. 59-166954
No. 57-179840, No. 57-186744, No. 58-149046, No. 59-168439,
No. 59-174834, No. 59-174835, No. 59-174832, No. 59-174833,
JP 60-2950, JP 59-181604, JP 59-182501, JP 59-179657, JP 59-18250, JP 59-d.

2813, and the image forming method using the above-mentioned photothermographic element and image-receiving element is also described in JP-A No. 59-1 in addition to the above-mentioned publications and specifications.
No. 82785, No. 59-158289, No. 59-12
No. 4332, No. 59-156791, JP-A-59-2
No. 23425, No. 60-19138, No. 60-130
It is known from various publications such as No. 735 and specifications.

Regarding the development processing method for such a diffusion transfer type heat-developable photosensitive element (hereinafter simply referred to as a heat-developable photosensitive element), Japanese Patent Laid-Open Nos. 60-135944, 130-135947, 60-146262, etc. As described in the specification, after exposure, a step of overlaying an image receiving element having a dye fixing portion on the heat-developable photosensitive element so that the photosensitive layer of the photosensitive element and the dye fixing layer are in close contact with each other, the image receiving element The process consists of a heating step of thermally developing the superimposed photothermographic elements, diffusing and transferring the imagewise formed dye image onto the image-receiving element, and a step of peeling the image-receiving element from the photothermographic element.

Among the above steps, the step of overlapping the image receiving element with the heat-developable photosensitive element is usually carried out by heating both sheet-like elements and applying pressure to bring them into close contact.

That is, as a typical example, an image receiving element and a heat-developable photosensitive element are superimposed between a pair of rollers that can uniformly heat and apply pressure so that the surface of the dye fixing layer and the surface of the photosensitive layer are aligned. This is done by passing it through.

Next, both overlapping elements are uniformly heated and thermally developed, and the dye released from the heat-developable photosensitive element is transferred to the dye-fixing layer by the heat development, and then the two sheets are peeled off to form an image-receiving layer. An image can be formed on the element.

However, in the conventional heat development method, the adhesion between the image receiving element and the photothermographic element is not necessarily good, and the image receiving element after peeling shows uneven transfer density due to poor adhesion.

Japanese Patent Application No. 60-3644 filed by the present inventors was intended to improve this poor adhesion, but although this method improves the unevenness of transfer density to a considerable extent, it is not possible to improve it sufficiently and stably. No, further improvements were desired.

[Object of the Invention] Therefore, the first object of the present invention is to provide a heat development method in which transfer unevenness is improved using a diffusion transfer type heat-developable photosensitive element and an image receiving element. An object of the present invention is to provide a heat development device suitable for use in the above heat development method.

[Structure of the Invention] The first object of the present invention is to superimpose an exposed diffusion transfer type heat-developable photosensitive element and an image-receiving element, heat develop the photosensitive element with the image-receiving element superimposed thereon, and develop the photosensitive element in an imagewise manner. Achieved by a heat development method comprising a heating step of diffusing and transferring the formed dye image to an image-receiving element, in which a pre-heating step of the image-receiving element is provided before the step of overlapping the photosensitive element and the image-receiving element. be done.

Furthermore, the second object of the present invention is to provide a means for superimposing an exposed diffusion transfer type heat-developable photosensitive element and an image receiving element, heat developing the photosensitive element on which the image receiving element is superimposed, and a dye formed in an imagewise manner. This is achieved by a heat developing device having a heating means for diffusively transferring an image to an image receiving element, in which a preheating means is provided on the image receiving element before being superimposed on the photosensitive element.

[Specific Structure of the Invention] The present invention is characterized by providing a step of warming the image-receiving element before the step of overlapping the image-receiving element with the diffusion transfer type photothermographic element after imagewise exposure.

The effects of the present invention obtained by such a method are considered to be based on the following reasons.

Generally, an image-receiving element is made by coating paper or other synthetic polymer sheets with an image-receiving layer containing a mordant polymer for fixing the heat-transferable dye that diffuses and migrates from the heat-developable photosensitive element. be.

It is considered that a considerable amount of moisture and gas are present in the image-receiving layer, and especially in the paper support in the case of a paper support. In the process of overlapping the heat-developable photosensitive element and the image-receiving element, heat development, and diffusion transfer, the moisture and gas contained in this image-receiving element become water vapor and gas that inhibit the adhesion between the two elements, causing serious transfer unevenness. It is thought to cause

The present invention has improved the register from this point of view,
According to the present invention, the adhesion between the image-receiving element and the photosensitive element as described above can be significantly improved compared to the conventional art.

Further, in the present invention, it is preferable to combine preheating of the photosensitive element as described in Japanese Patent Application No. 60-3644 previously filed by the present applicant.
By using both preheating of the image receiving element, uneven adhesion can be significantly improved.The temperature and time should be sufficient to remove moisture.If the temperature is lower, the heating time is longer; if the temperature is higher, the heating time is sufficient. You can choose freely for a short period of time.

The temperature required for the preheating step of the image receiving element according to the present invention and the preheating step of the preferably combined photosensitive element is preferably 80° C. to 250° C., more preferably 10° C.
The temperature ranges from 0°C to 200°C, and the heating is performed for a time necessary to sufficiently remove each moisture content. Therefore, when the preheating temperature is high, a short time is required, and when the preheating temperature is low, a long time is required. The time also varies depending on the type and material of the image receiving element, photosensitive element, etc. For example, if the support of the image receiving element is a paper support or the like, sufficient preheating is required, whereas if it is a PET base or the like, the preheating time may be short. For example, if the binder of the image-receiving layer or photosensitive layer is a hydrophilic binder such as gelatin, PVA, or PVP, sufficient preheating is required; if the binder is a hydrophobic binder, a relatively short heating time is required. good.

The general heating time is preferably 0.1 seconds to 60 seconds, more preferably 1 second to 20 seconds.

The image-receiving layer of the image-receiving element that can be effectively used in the present invention includes:
It may be a polymer containing a tertiary amine or a quaternary ammonium salt, as long as it has the function of receiving the dye in the heat-developable photosensitive layer released or formed by heat development, as described in US Pat.
Those described in No. 709,690 are preferably used. For example, as a polymer containing an ammonium salt, the ratio of polystyrene-N%N, N-tri-hexyl-N-vinyl-benzylammonium chloride is 1:4 to 4:1, preferably 1:1. be.

Examples of polymers containing tertiary amines include polyvinylpyridine. A typical image-receiving layer for diffusion transfer is obtained by mixing a polymer containing ammonium salt, tertiary amine, etc. with gelatin, polyvinyl alcohol, etc., and coating the mixture on a support.

Another useful dye-receiving material is JP-A-57-207
The glass transition temperature described in No. 250 etc. is 40°C or higher,
Examples include those formed of heat-resistant organic polymer substances of 250'C or less.

These polymers may be supported on a support as an image-receiving layer, or may themselves be used as a support.

As an example of the heat-resistant organic polymer substance, molecular barrier 2,0
00 to 85,000 polystyrene, polystyrene derivatives having substituents having 4 or less carbon atoms, polyacetals such as polyvinylcyclohexane, polydivinylbenzene, polyvinylpyrrolidone, polyvinylcarbazole, polyallylbenzene, polyvinyl alcohol, polyvinyl formal, and polyvinyl butyral. ; Polyvinyl chloride, chlorinated polyethylene, polytrichloride, polyethylene, polyacrylonitrile, poly N, N-dimethylallylamide, polyacrylate with p-cyanophenyl group, pentachlorophenyl group and 2,4-dichlorophenyl group , polyacrylic chloroacrylate, polymethyl methacrylate, polyethyl methacrylate, bolibu Ovir methacrylate, polyisopropyl methacrylate, polyisobutyl methacrylate, polytert
- Polyesters such as butyl methacrylate, polycyclohexyl methacrylate, polyethylene glycol dimethacrylate, poly-2-cyano-ethyl methacrylate, polyethylene terephthalate: polysulfone,
Examples include polycarbonates such as bisphenol A polycarbonate, polyanhydrides, polyamides, and cellulose acetates. In addition, Polymer Handbook, Second Edition, edited by G.I. Brandrup, E.H.
ook 2nded, (J, Brand
rup, E, H, Immergu
John W 1ley & S On
Synthetic polymers with a glass transition temperature of 40° C. or less, which are described in the publication S], are also useful. These polymeric substances are
It may be used alone or in a blend of two or more types, or two or more types may be used in combination.
A combination of two or more species may be used as a copolymer.

Useful polymers include cellulose acetates such as triacetate and diacetate, polyamides in combinations such as heptamethylene diamine and terephthalic acid, fluorene propylamine and adipic acid, hexamethylene diamine and diphenic acid, hexamethylene diamine and isophthalic acid, and diethylene glycol. Examples include polyester, polyethylene terephthalate, and polycarbonate made of a combination of bis-p-carboxyphenoxybutane, ethylene glycol, and diphenylcarbonate.

These polymers may be modified. For example, polyethylene terephthalate using cyclohexane dimetatool, isophthalic acid, methoxypolyethylene glycol, 1,2-dicarbomethoxy-4-benzenesulfonic acid, etc. as a modifier is also effective.

A particularly preferable image-receiving layer is JP-A-59-22342
Layer made of polyvinyl chloride described in No. 5 and JP-A-60
Examples include a layer made of polycarbonate and a plasticizer described in Japanese Patent No. 19138.

These polymers can also be used as a support and image-receiving layer (image-receiving element), in which case the support may be formed from a single layer or from multiple layers. good. As the support for the image-receiving element, any material such as a transparent support or an opaque support may be used, and examples thereof include polyethylene terephthalate, polycarbonate,
Films of polystyrene, polyvinyl chloride, polyethylene, polypropylene, etc.; supports containing titanium oxide, barium sulfate, calcium carbonate, talc, etc.; baryta paper; RC paper laminated with thermoplastic resin, cloth, glass, metals such as aluminum, etc., and supports on which electron beam curable resin compositions containing pigments are applied and cured; Examples include supports in which a coating layer containing a pigment is provided on these supports.

In particular, a support prepared by coating and curing an electron beam curable resin composition containing a pigment on paper, or directly on paper or with a pigment coating layer and an electron beam curable resin composition on the pigment coating layer. The support coated with the resin and cured can be used as an image-receiving element as it is because the resin layer itself can be used as an image-receiving layer.

In the present invention, following the preheating step of the image receiving element and the photosensitive element preferably used together, the photosensitive element and the image receiving element are overlapped. This step of overlapping the photosensitive element and the image receiving element may be performed by overlapping the elements so that they are in close contact with each other, but it is preferably performed by heating under a constant pressure. The heating temperature in this overlapping step is preferably 80°C to 250°C, more preferably 100°C.
~200°C. As in the present invention, if the water content of both the image receiving element and the photosensitive element preferably used together is sufficiently removed by preheating, there is no need for a very high pressure in the overlaying process, and the pressure during the heating is 0.
01 kg/Ct' or more and 100 kg/Cf or less, preferably 0.1 kg/Cf or more and 50 ka/cf or less.

According to the present invention, after the process of overlapping the photothermographic element and the image-receiving element as described above is completed, a heating process is subsequently performed in which thermal development and thermal transfer are simultaneously carried out while the elements remain in close contact with each other.

The heating temperature required for the heating step for the above thermal development and thermal transfer is preferably 80°C to 250°C, more preferably 100°C to 200°C, and the time is 0.1 second to 250°C.
The heating time is preferably 300 seconds, and more preferably in the range of 5 seconds to 180 seconds. In some cases, for a short period of time (e.g. 180℃
(10 seconds), and the optimum time is determined at each temperature. Also, in the heating process for thermal development and thermal transfer, if the image receiving element and the photosensitive element are completely brought into contact in the overlapping process that is performed prior to the heating process for thermal development and thermal transfer, it is not necessary to apply too high a pressure. No need to spend 1k
CI/Cv' or less is preferable, more preferably 50h/
A pressure range of C.2 or less is sufficient.

The step of overlapping the photosensitive element and image receiving element of the present invention includes:
It may be performed simultaneously with a heating step for thermal development and thermal transfer while applying a constant pressure.

Any heating means may be used for preheating the image receiving element according to the present invention, for preheating the photosensitive element preferably used in combination, for heating in the overlapping process, and for heating for thermal development and thermal transfer. For example, means for heating by passing between hot plates or by contacting with a hot plate, means for heating by being held between or in contact with a rotating heat drum or heat roller,
Various methods can be used, such as means for heating the material by passing it through hot air, and means for heating the material by conveying it along a heat source using rollers, belts, or guide plates, and bringing it into contact with the heat source.

Alternatively, a layer of conductive material such as graphite, carbon black, or metal is laminated on a heat-developable photosensitive element, and an electric current is passed through the conductive layer to heat the element using Joule heat generated. You can also do it.

A method of preheating the image receiving element that is particularly useful in the present invention is to use a preheating zone between a flat heater and a porous plate facing the heater and designed to bring the image receiving element into uniform contact with the heater. Particularly preferred is an image-receiving element preheating means in which the image-receiving element is conveyed by a feed roller so that the back surface of the image-receiving element is in contact with a flat heater. As a result, while the image receiving element is being transported, moisture is diffused from the image receiving layer surface of the image receiving element through the porous plate due to heating.

This porous plate needs to be strong enough not to interfere with the conveyance of the image receiving element so that the back surface of the image receiving element is brought into uniform contact with the flat heater. Therefore, in order to satisfy the above conditions, it is preferable to weakly press the porous plate against the heater surface with a spring, or to adjust the distance between the heater and the porous plate to just the thickness of the image receiving element. The porous plate is made of heat-resistant plastic, such as a bakelite plate or mesh, with multiple holes for the release of water vapor and gas, as long as it does not hinder the diffusion of water vapor and gas. There are no restrictions on the shape or number of holes used.

Further, in the present invention, a preferable thermal developing means includes a rotating drum made of a highly thermally conductive metal such as aluminum, equipped with a heating means such as electric resistance, and a heat-resistant belt that is in pressure contact with the rotating drum and rotates in synchronization with the drum. The diffusion transfer type heat-developable photosensitive element and the image receiving element are stacked so that the emulsion surface and image receiving layer surface of each are in close contact with each other and are conveyed while being sandwiched between the rotating drum and the belt.

The heating rollers, which are these rotating drums, are preferably made of aluminum, and the heat-resistant belts are metal, such as endless belts such as stainless steel, or heat-resistant belts. An endless belt made of carbon-containing silicone rubber or fluororubber is preferable, and the core material is an endless belt made of I fibers (for example, Nomex). It is preferable to have one.

Hereinafter, the present invention will be explained in more detail with reference to the drawings. The drawing is an example showing a preferred embodiment of the present invention.

FIG. 1 is an explanatory diagram showing a schematic configuration of a heat developing apparatus according to the present invention.

In the figure, a roll-shaped heat-developable photosensitive element 1 is guided by guide rollers 2 to an exposure position, where it is image-exposed by a CRT 3. As shown in FIG. On the other hand, the image receiving element 5 is preheated by a flat plate heater 4 at a stage before it is overlapped with the exposed photosensitive element 1 from the side opposite to the overlapping surface of the image receiving element 5. Further, at this time, it is more preferable that the photosensitive element 1 is also provided with a flat heater 4' at a stage before being overlapped with the image receiving element 5 so that the photosensitive element 1 is preheated. The image receiving element 5 and the photosensitive element 1 which have undergone the above preheating are
They are overlapped by a pair of heating rollers 6.7 and brought into close contact with each other by heating and pressure, and as the heating rollers 6.7 rotate, they are guided by the guide plate 8 and reach the thermal development transfer section.

The thermal development transfer section as an embodiment of the thermal development transfer device of the present invention is mainly composed of two endless belts stretched vertically and a heat plate heated by a heater.

That is, 9 is an endless belt that is stretched around the drive rollers 11a and 11b and can rotate as the drive rollers 11a and 11b rotate, and 10 is provided below the endless belt 9 and is attached to the drive rollers 12a and 11b. This is a non-biting belt that is stretched around the drive rollers 12b and can rotate as the drive rollers 12a and 12b rotate.

Inside the endless belt 10, there are heaters 13a and 13b as heating members;
A heat plate 14 that is heated by is built-in.

The reason for using a plurality of heaters as described above in the present invention is to facilitate adjustment of heating temperature and heat distribution.

Further, in the present invention, as shown in the figure, the shape of the contact surface of the heat plate 14 with the endless belt 10 is made into a gentle curved shape, so that an appropriate tension is applied to the endless belt 10, and the upper part of the endless belt 10 and Since the surface in pressure contact with the endless belt 9 can be formed in a curved shape, when the photosensitive element and the image receiving element are conveyed under heat, adhesion between the two elements is promoted, and at the same time, misalignment in conveyance is prevented. Ru.

Heat conduction from the heat plate 14 to the endless belt 10 is also improved.

A tension roller 15 located at the center of the upper endless belt 9 and provided in pressure contact with the endless belt 9 applies a light pressure to the endless belt 9, giving tension to the belt.

The heat-developable photosensitive element 1, which has been closely overlapped with the image-receiving element 5 as described above, is carried into the heat-developable transfer section configured as described above, and is held between two upper and lower endless belts 9 and 1o, and is held in place by the rotation of the belts. The images are conveyed in close contact with each other, thermally developed, and at the same time, the movable color image is transferred to the image receiving element 5 and sent out from the endless belt.

The photothermographic element overlapped with the image receiving element sent out by the endless belts 9 and 10 is taken up by the take-up roller 16 provided at a position slightly downward with respect to the conveyance direction, but the downward force acting at this time The image receiving element is peeled off and separated from the photothermographic element, guided by a guide roller 17, cut into a predetermined length by a cutter 18, and accumulated on a sheet in a storage section 19.

Further, FIG. 2 shows only the close contact portion of another heat developing device of the present invention. In this device, the image receiving element 5 sent out from the roll of the image receiving element 5' is preheated by being conveyed while being in close contact with a heating roller 7' for a fixed length as shown in the figure. It is also conveyed in the same manner and heated by the heating roller 6'.
The photosensitive element 1', which has been preheated by the heating rollers 6' and 7', is brought into close contact with the heated rollers 6' and 7'. In these examples, only apparatuses using roll-type photosensitive elements are illustrated, but it goes without saying that similar effects can be obtained with apparatuses that process photosensitive elements one by one.

FIG. 3 is an explanatory view of the main parts of still another heat developing apparatus of the present invention.

In the figure, the image receiving element 5' is the feed roller 21a, 2
1b, and the photosensors 22a and 22b
a feed roller 24a along the guide 23 through the
24b. The length of the image receiving element 5' is determined by the position of the photosensor 22a122b and the feed roller 24a1.
The distance between the image receiving element 5' and the axis of the image receiving element 5' is set slightly shorter than the distance between the axis of the image receiving element 5' and the feed rollers 24a, 24.
Photo sensors 22a and 22b are placed in the mouth of b.
The rear end of the image receiving element 5' passes through, and at the same time, signals from the photosensors 22a and 22b that detect this actuate an electromagnetic switch to stop the feed rollers 24a and 24b, and the tip of the image receiving element 5' passes through the feed roller. 24a,
It stops with 24b still in its mouth.

On the other hand, the photosensitive element 1' of the exposure stream is fed by a feed roller 25a,
25b to the thermal development transfer section, but before the photosensitive element 1' is sent to the transfer section, it is in contact with the thermal drum 14', and on the drum 14', substantially all of the moisture in the photosensitive element 1' is removed. (section 2 shown in the drawing is the preheating section) is preheated to a sufficient extent to evaporate. After the photosensitive element 1' subjected to this preheating leaves the feed rollers 25a and 25b, it is conveyed along the guides 26 and 27, and when the photosensitive element 1' touches a microswitch 28 provided on the guide 27, the photosensitive element 1' image receiving element 5'
The feed roller 24a is stopped with the
, 24b are driven again, and the image receiving element 5' is conveyed between the flat heating plate 4' for preheating and the opposing mesh-like guide 29 which also serves as a press. Then, the tips of the preheated photosensitive element 1' and the image receiving element 5' are brought together and sent to a thermal development transfer section. This heat development transfer section includes a heating drum thermal belt 10' made of aluminum.
(consisting of an endless belt of silicone rubber woven with Nomex fibers, the surface of which is polished), and a plurality of rollers that tension and drive this belt 10';
That is, it consists of a drive roller 301, a tension roller 31, and an idling roller 32. The preheated photosensitive element 1' and the image receiving element 5', which are fed into the thermal development transfer section, are thermocompressed and subjected to thermal development transfer. Next, the photosensitive element 1' subjected to thermal development transfer and the image receiving element 5 in close contact therewith.
' can be peeled off by hand to obtain a clear dye image on the image receiving element 5'.

Furthermore, as another embodiment of the present invention, the drive roller 30 of the endless belt 10' facing the metal drum 14' may be brought into pressure contact with the metal drum with a constant pressure to function as a laminate, in which case the image receiving element 5′
and the photosensitive element 1' includes a heating drum 14' and a roller 30.
Since it is laminated, it will fit more tightly. ! After being deposited, the image is developed and transferred while being conveyed between the heating drum 14' and the belt 10'. In the present invention, a very high pressure is not required, but these methods can be used in combination when the pressure between the heating drum 14' and the belt 10' alone is insufficient for adhesion.

Although FIG. 3 shows an example of a heat developing device in which an image receiving element and a photosensitive element are inserted together, there is also a method in which the image receiving element and photosensitive element are fed into the heat developing device after exposure from an image receiving element cassette and a photosensitive element cassette at the same timing. It may be combined with other methods, and may also be combined with various peeling means after heat development.

Having described the invention, it will be obvious that various modifications may be made, and such modifications should not be considered as departing from the spirit and scope of the invention.

In the present invention, the imagewise exposure method for recording a latent image on a heat-developable photosensitive element includes a full-surface exposure method such as in a normal color printer, or a scanning exposure method by optically converting computer data or video signals. You may do so.

Therefore, the light source is generally a tungsten lamp.
Mercury lamps, halogen lamps such as iodine lamps, and other CR
Examples include T, 0FTS LED, laser, and the like.

In addition, in the step of separating the heat-developable photosensitive element and the image-receiving element, in order to peel off the image-receiving element after the transfer from the heat-developable photosensitive element, for example, the method described in JP-A-60-135944, or other known methods may be used. The following methods can be used.

Also, when the temperature of the heat-developable photosensitive element is low (for example, 80"C
(below), development and transfer do not proceed much, so 8
After cooling to below 0°C or below 60°C, it may be peeled off with fingers.

[Specific Effects of the Invention] As explained above, in the present invention, an image receiving element is preheated to reduce moisture content, and then superimposed on a hazy photothermographic element, thermally transferred, and released from the photothermographic element. By diffusing and transferring the formed dye to the image-receiving element, a high-quality color image without uneven transfer is formed on the image-receiving layer.

[Specific Examples of the Invention] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 First, methods for preparing a heat-developable photosensitive element and an image-receiving element will be described below.

[Preparation of silver 4-sulfobenzotriazole] 24 g of 4
-Sulfobenzotriazole and 4 g of sodium hydroxide were added to and dissolved in ethanol-water (1:1) mixture 3001Q. A 5N silver nitrate solution 201Q was added dropwise to this solution. At this time, a 5N sodium hydroxide solution was also added dropwise at the same time to maintain I)H at 7-8. After stirring this solution for 1 hour at room temperature, it was made up to 400112 with water and 4-
A 4-sulfobenzotriazole silver solution containing 20% excess of sulfobenzotriazole was prepared.

[Preparation of photosensitive element] The following dye-providing polymer (PM-1>470m
a and 1,4-dioctylhydroquinone 30ma to ethyl acetate 2. Dissolved in IOC. This solution was mixed with 3 cc of a 2.5% gelatin aqueous solution containing a surfactant, water was added to make e, scc, and then dispersed with a homogenizer.
A dispersion of a dye-providing polymer was obtained. The above 4-sulfobenzotriazole silver solution 41Q and dye-donating polymer dispersion 6CC were mixed, and further 450 mg of polyvinylpyrrolidone (average molecular weight 130,000), 120 mg of pentaerythritol, 420 mg of 1,5-bentanediol and the following reduction were added. Agent (R-3) 200mg
was added, and the pH was adjusted to 5.5 with 3% citric acid. To this dispersion, 3X10-4 mol of silver iodobromide emulsion with an average particle size of 0.05 μm was added (containing 751 g of gelatin) in terms of silver, and after adding water to make a final total of 141 g, the emulsion was transferred onto a polyethylene terephthalate support. A photosensitive layer was coated with a wire bar so that the dry film thickness was 8 μm, and a photosensitive element was prepared.

(PM-1) y: 50% by weight (R-3) Hs [Preparation of image-receiving element] An image-receiving element was prepared by coating polyvinyl chloride at 10 g/-f on baryta paper.

Using the heat-developable photosensitive element and image-receiving element produced as described above, heat development and heat transfer were carried out using the heat development apparatus according to the present invention shown in FIG.

The overall line speed in the thermal development apparatus of the present invention is 1
0mm/sea, the length of the flat plate heater 4 of the image receiving element is 3011, and the heat development transfer heaters 13a and 131
) is 300 cm, and in this embodiment, the temperature of the flat heater 4 is 23°C (room temperature), 60°C, 80°C, 1
The temperature was changed to 00°C, 130°C and 150°C. Further, the temperature of the heating roller 6.7 used in the step of bringing the photothermographic element and the image receiving element into close contact is 150°C.
The pressure between 7 and 7 was 5 kg/cv using spring pressure. The heat development temperature was set at 150℃, and the line speed was 10m.
m/SeC, the heat development time is about 30 seconds.

By setting the processing conditions as above, the image forming area is 100.
Using an exposed heat-developable photosensitive element and an image receiving element having a size of mm xiomm, a color image was formed on the image receiving element by the above-mentioned apparatus, and the characteristics of the transferred image were evaluated, and the results are shown below.

Among the evaluation values shown in Table 1 below, transfer unevenness was evaluated according to the following criteria.

Transfer unevenness: 1 per 100C1' where white spots are quite noticeable
0 or more △: Up to 2 to 3 white spots per 100cl O: There are no white spots, but there is some unevenness in density! ! Table 1 As is clear from the results in the above table, applying heating to reduce the moisture content of the image receiving element as a pre-process of superimposing the photothermographic element and the image receiving element has an adverse effect on the image characteristics. It has been found that the transfer unevenness of images formed on image receiving elements is improved without the use of

Example 2 In addition to the preheating of the image receiving element shown in Example 1, a flat plate heater for preheating the photosensitive element was attached to the part indicated by 4' in FIG.
The transfer unevenness of the transferred image was evaluated at 0°C, and the second
The results shown in the table were obtained. The evaluation criteria for uneven transfer are as follows.

×: White spots are quite noticeable 10 per 100 cf
△: There are 2 to 3 white spots per 100 Cf. ○: There are no white spots, but density unevenness is observed. ◎: White spots are uniform and there is no density unevenness. This is clear from the results in Table 2. As shown above, it can be seen that by preheating the photosensitive element in addition to the image receiving element before the step of overlapping the photosensitive element and the image receiving element, it is possible to further eliminate density unevenness and obtain an excellent image.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram of a heat developing device used in the present invention, and FIGS. 2 and 3 are explanatory diagrams of main parts of the heat developing device showing other embodiments. be. 1.1'...Thermal development photosensitive element 3...CRT 4.4'...Flat heater 5.5'...Image receiving element 6.6', 7.7'...Heating roller 9 .1.0.
10'...Endless belt 14.14'...Thermal development transfer phase heating section Patent applicant: Konishiroku Photo Industry Co., Ltd. Procedure correction layer (self-imposed December 14, 1988 El Patent application No. 14683, 1988) 2. Name of the invention Thermal developing method and thermal developing device that improve transfer unevenness 3. Relationship with the case of the person making the amendment Patent applicant address 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name
(127) Representative Director of Konishiroku Photo Industry Co., Ltd.
Keio Benko 4, Agent 102 Address: Kudan-Rosaka Pill, 4-1-1 Kudankita, Chiyoda-ku, Tokyo Tel: 263-9524 6. Contents of the amendment The detailed description of the invention in the written description is amended as follows. . (1) Delete the statement "...mordant..." on page 9, lines 5-6 of Akirall1I. that's all

Claims (11)

[Claims] (1) A step of superimposing an exposed diffusion transfer type heat-developable photosensitive element and an image-receiving element, heat-developing the photosensitive element with the image-receiving element superimposed thereon, and diffusing and transferring the imagewise formed dye image to the image-receiving element. In a heat development method having a heating step,
A thermal development method, characterized in that a step of preheating the image receiving element is provided before the step of overlapping the photosensitive element and the image receiving element. (2) The thermal development method according to claim (1), further comprising a step of preheating the photosensitive element before the step of overlapping the photosensitive element and the image receiving element. (3) A preheating step of the image receiving element provided before the step of overlapping the photosensitive element and the image receiving element is provided so as to contact a surface of the image receiving element opposite to a surface to be overlaid with the photosensitive element. The thermal development method according to claim 1 or claim 2, characterized in that the heating step is performed using a flat heater or a heating roller. (4) A preheating step of the photosensitive element provided before the step of superimposing the photosensitive element and the image receiving element is provided so as to be in contact with a surface of the photosensitive element opposite to a surface on which the image receiving element is superimposed. The thermal development method according to claim 2 or 3, characterized in that the heating step is performed using a heating roller or a flat heater. (5) The preheating step of the photosensitive element is performed by a heating roller, and the heating roller is used for the heating step of thermally developing the photosensitive element and diffusing and transferring the imagewise formed dye image to the image receiving element. The heat developing method according to claim (4), characterized in that: (6) A means for superimposing an exposed diffusion transfer type heat-developable photosensitive element and an image receiving element, thermally developing the photosensitive element with the image receiving element superimposed thereon, and diffusing and transferring the imagewise formed dye image to the image receiving element. In a thermal development apparatus having a heating means,
A thermal developing device characterized in that a preheating means is provided on the image receiving element before being superimposed on the photosensitive element. (7) The thermal development apparatus according to claim (6), further comprising a preheating means for the photosensitive element before being superimposed on the image receiving element. (8) Preheating means provided on the image receiving element before being superimposed on the photosensitive element is a flat heater or heating roller provided so as to contact the surface of the image receiving element opposite to the surface on which the photosensitive element is superimposed. Claim (6) or (7) characterized in that the heating means is a heating means according to
) The thermal development device described in item 2. (9) The preheating means for the photosensitive element is a flat heater, and a pressing plate made of a porous material with water permeability for uniformly contacting the image receiving element with the heater; Claims (6), (7), or (8) further comprising a feed roller for conveying the image receiving element while being heated between the heater and the pressing plate. ) The thermal development device described in item 2. (10) Preheating means provided on the photosensitive element before being superimposed on the image receiving element is a flat heater or heating roller provided so as to contact a surface of the photosensitive element opposite to a surface on which the image receiving element is superimposed. Claims (7) and (8) characterized in that the heating means is
or (9). (11) The preheating means for the photosensitive element is a heating roller, and the heating roller is used as a heating means for thermally developing the photosensitive element and diffusing and transferring the imagewise formed dye image to the image receiving element. A heat developing device according to claim (10), characterized in that: