JP2006133490A - Heat developing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat developing apparatus where, though the number of parts can be reduced and its miniaturization can be attained, the unevenness in concentration is suppressed, and a film sheet can be stably carried. <P>SOLUTION: The heat developing apparatus is provided with: a first zone 50 composed of fixed guides 51b, 52b having a heater 51c and counter rollers 51a, 52a pressing a film toward the fixed guides; a second zone 53 composed of a curvature guide 53b having a heater 53c and an another curvature guide 53a, and in which a prescribed gap d is formed between the curvature guides; and a cooling means 54 of cooling the film. The film progressing position of each curvature guide in the second zone lies at the position lower than the curvature center P thereof, the carrying direction to the second zone by the counter rollers is made into a separation direction from the center of the curvature guide, and further, the film is guided into the direction opposite to that of gravity via the second zone by the carrying force by the counter rollers. Each curvature guide in the second zone guides the film to the cooling means at the position lower than the curvature center thereof, and visualizes the latent image on the film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat development apparatus for visualizing a latent image formed on a sheet film.

  Patent Document 1 below discloses an apparatus for developing a film on which a latent image is formed by heating a sheet film between a heated heating drum having a flexible layer and a plurality of opposing rollers. The following Patent Document 2 discloses an apparatus of a system in which a fixed heater divided into three is used instead of the heating drum, and the BC surface of the film is slid and heated on the heater. Further, Patent Document 3 below discloses a heat development apparatus that heats a film through a slit formed on the outer periphery of a drum. Patent Document 4 below discloses a dry gray image processing apparatus that is miniaturized so that exposure, development, and cooling are continuously performed, and exposure processing and heat treatment are simultaneously performed in parallel.

Even a relatively large machine as in Patent Documents 1 to 3 and a small machine as in Patent Document 4 employ a uniform heating method in the film conveyance direction. The former device can achieve uniform image quality by using a uniform heating method and demonstrate a large amount of processing capacity, but in the latter half of the heating process, the film is heated and transported with more precision than necessary. Cost reduction due to reduction cannot be expected. On the other hand, in the latter case, uneven density tends to occur, and it is sometimes difficult to improve the film transport posture.
Japanese National Patent Publication No. 10-500497 JP 2003-287862 A U.S. Pat. No. 3,739,143 JP 2002-162692 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a thermal development apparatus that can reduce the number of parts and can be downsized while suppressing unevenness in density and stably transporting a film sheet. To do.

  In order to achieve the above-mentioned object, the present inventor, as a result of earnest studies, the heat development process comprises a temperature raising step for raising the temperature of the film to the heat development temperature and a heat retention step for keeping the heated film warm. In the temperature raising step, uniform heating over the entire surface of the film (in other words, close contact in heat transfer between the film and the heating member) is important. If this uniform heating is not guaranteed, uneven heating (that is, uneven concentration) occurs. It is easy to occur, and the latter heat retention process has acquired the knowledge that close contact between the heating member and the film is not so important as compared to the former, and based on such knowledge, the above-described temperature raising process and heat insulation process can be performed and The present inventors have conceived a heat developing device structure that can achieve conveyance stability and downsizing.

  That is, the thermal development apparatus according to the present invention is a thermal development apparatus that visualizes a latent image formed on a sheet film that is conveyed while heating a sheet film coated with a photothermographic material on one side of a support substrate. A first zone which is composed of a fixed guide having a heater and a rotationally driven counter roller which presses the sheet film toward the fixed guide, and is arranged on the upstream side in the conveying direction; and a curvature guide having a heater. And a second zone that is formed on the downstream side in the conveying direction with a predetermined gap formed between the curvature guides, and the sheet film heated by the heating unit is cooled. Cooling means, and the film entrance position of the curvature guide of the second zone is a position below the center of curvature, and the second zone by the opposing roller The sheet film is guided in the anti-gravity direction via the second zone by the conveying force of the counter roller, and the conveyance direction to the curvature guide is a direction away from the center of the curvature guide. The curvature guide guides the sheet film toward the cooling means at a position below the center of curvature.

  According to this thermal development apparatus, in the first zone, the sheet film is heated and heated while being brought into contact with the fixed guide by the opposing roller, and in the second zone, the sheet film is placed in the slit formed between the curvature guides. By heating and keeping warm, a rapid thermal development process can be realized while suppressing the occurrence of density unevenness. Further, in the second zone, it can be conveyed while being heated (insulated) between the slits by the conveying force of the opposing roller of the first zone, so that no driving parts for the conveying system are required, and the accuracy of the slit dimensions is not required so much. Furthermore, since the second zone is constituted by a curvature guide, the apparatus can be reduced in size and cost. Further, the sheet film is guided in the antigravity direction through the second zone, and the curvature guide guides the sheet film toward the cooling means at a position below the center of curvature, so that the sheet film is conveyed toward the cooling process. It is preferable because the posture of the sheet film can be stabilized and the volatile substances in the slit portion due to the gaps become ascending currents and are easily discharged from the second zone.

  In the heat development apparatus, it is preferable that the angle formed by the film entrance portion to the second zone and the film discharge portion from the second zone is 90 degrees or less.

  In the first zone, at least two fixed guides each having a heater are juxtaposed in the transport direction, the upstream side of the fixed guides is heated to a heat development start temperature or lower, and the downstream side is a heat development temperature. It is preferable to constitute so that it heats up to. Thereby, each heater of each fixed guide is controlled independently, and by heating from room temperature to the heat development start temperature or lower on the upstream side, the load fluctuation in the heater is less than the temperature rise to the heat development temperature. The temperature controllability at the time of raising to the heat development temperature on the downstream side can be improved.

  According to the heat development apparatus of the present invention, it is possible to reduce the number of parts and reduce the size, while suppressing density unevenness and stably conveying the film sheet.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a side view schematically showing a main part of the heat development apparatus according to the present embodiment.

  As shown in FIG. 1, the thermal development apparatus 40 of this embodiment includes an EC surface in which a photothermographic material is coated on one side of a sheet-like support base made of PET or the like, and a support opposite to the EC surface. A latent image is formed on the EC surface by the laser beam L from the optical scanning exposure unit 55 while the film F having the BC side on the substrate side is transported in the sub-scanning state, and then the film F is heated and developed from the BC surface side. Then, the latent image is visualized, conveyed to the upper part of the apparatus through a curved conveying path, and discharged.

  The heat development apparatus 40 in FIG. 1 picks up and conveys a film storage section 45 provided near the bottom of the apparatus housing 40a for storing a large number of unused films F, and the uppermost film F in the film storage section 45. Pick-up roller 46 to be transported, transport roller pair 47 to transport film F from pick-up roller 46, and guide film F from transport roller pair 47 so that the film F is turned upside down and transported while substantially reversing the transport direction. A curved surface guide 48 configured in a curved surface, a pair of conveyance rollers 49a and 49b for sub-scanning conveyance of the film F from the curved surface guide 48, and the image data on the film F between the conveyance roller pairs 49a and 49b. And an optical scanning exposure unit 55 that forms a latent image on the EC surface by performing optical scanning with the laser beam L and performing exposure.

  The thermal developing device 40 further heats the film F on which the latent image is formed from the BC surface side to raise the temperature to a predetermined heat development temperature, and heats the heated film F to a predetermined temperature. A heat retaining section 53 that retains the heat development temperature, a cooling section 54 that cools the heated film F from the BC surface side, a densitometer 56 that is disposed on the outlet side of the cooling section 54 and measures the density of the film F, A transport roller pair 57 that discharges the film F from the densitometer 56, and a film mounting portion that is provided on the upper surface of the apparatus housing 40a so that the film F discharged by the transport roller pair 57 is mounted. 58.

  As shown in FIG. 1, in the thermal development device 40, upward from the bottom of the apparatus housing 40 a, the film storage unit 45, the substrate unit 59, the conveyance roller pairs 49 a and 49 b, the temperature raising unit 50, and the heat retaining unit 53 (upstream). The film storage portion 45 is at the lowermost position, and the substrate portion 59 is provided between the temperature raising portion 50 and the heat retaining portion 53, so that it is not easily affected by heat.

  Further, since the conveyance path from the pair of conveyance rollers 49a and 49b for the sub-scan conveyance to the temperature raising unit 50 is configured to be relatively short, the front end of the film F is exposed while the light F is exposed to the film F by the optical scanning exposure unit 55. On the side, heat development heating is performed by the temperature raising unit 50 and the heat retaining unit 53.

  The temperature raising part 50 and the heat retaining part 53 constitute a heating part, and the film F is heated to the heat development temperature and maintained at the heat development temperature. The temperature raising unit 50 includes a first heating unit 51 that heats the film F to the heat development start temperature or lower on the upstream side, and a second heating unit 52 that heats the film F to the heat development temperature on the downstream side.

  The first heating unit 51 includes a planar heating guide 51b made of a metal material such as aluminum and fixed, a planar heating heater 51c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 51b, A plurality of opposing rollers 51a made of silicon rubber or the like, which is arranged so as to maintain a gap narrower than the film thickness so that the film can be pressed against the fixed guide surface 51d of the guide 51b and whose surface is thermally insulating compared to metal or the like; Have

  The second heating unit 52 includes a planar heating guide 52b made of a metal material such as aluminum and fixed, a planar heating heater 52c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 52b, A plurality of opposing rollers 52a made of silicon rubber or the like, which is arranged to maintain a gap narrower than the film thickness so that the film can be pressed against the fixed guide surface 52d of the guide 52b, and whose surface is more thermally insulating than metal or the like; Have

  The heat retaining section 53 is made of a metal material such as aluminum and has a heating guide 53b configured and fixed with a predetermined curvature, and a curved heater 53c made of a silicon rubber heater or the like that is in close contact with the back surface of the curved heating guide 53b. And a curved surface guide 53a made of a heat insulating material or the like, which is arranged to face the fixed guide surface 53d on the surface of the heating guide 53b so as to have a predetermined gap (slit) d and is configured with a predetermined curvature.

  In the first heating unit 51 of the temperature raising unit 50, the film F conveyed by the conveying roller pairs 49a and 49b from the upstream side of the temperature raising unit 50 is pressed against the fixed guide surface 51d by the respective opposed rollers 51a that are rotationally driven. As a result, the BC surface comes into close contact with the fixed guide surface 51d and is conveyed while being heated.

  Similarly, in the second heating unit 52, the BC surface is fixed to the fixed guide surface 51d by pressing the film F conveyed from the first heating unit 51 against the fixed guide surface 52d by each counter roller 52a that is rotationally driven. It is conveyed while being in close contact with and heated.

  The film F is linearly conveyed by the flat fixed guide surfaces 51d and 52d of the first and second heating units 51 and 52 in the temperature raising unit 50. Correspondingly, the film F is the first one. Since it is linearly conveyed by the conveyance roller pair 49a, 49b toward the heating unit 51, the impact when the leading edge of the film F enters the uppermost counter roller 51a of the first heating unit 51 is reduced.

  The film entrance 53e of the heat retaining section 53 is located below the horizontal line g passing through the center of curvature P of the heating guide 53b having a predetermined curvature, and the film outlet 53f is located below the horizontal line g passing through the center of curvature P. The part 53 guides the film from the film discharge port 53f toward the cooling part 54.

  In FIG. 1, the angle formed by the film entrance 53 e of the heat retaining unit 53 and the film discharge port 53 f is configured to be 90 degrees or less. That is, in the heat retaining portion 53, the film is conveyed in a substantially horizontal direction from the second heating portion 52 of the temperature raising portion 50 to the film entrance 53e of the heat retaining portion 53 by the opposing roller 52a, and vertically from the film discharge port 53f. It is discharged in a direction slightly inclined to the direction and is directed to the cooling unit 54.

  As described above, in the heat retaining section 54, the film transport direction by the facing roller 52a of the second heating section 52 on the upstream side is set to the separation direction from the center P of the curvature guide, and the heat retaining section is driven by the transport force by the facing rollers 52a and 51a. The film is guided in the antigravity direction via the heat retaining portion 54 by gradually changing the transport direction in the gap d of 54.

  In the cooling unit 54, the film F conveyed in the substantially vertical direction from the heat retaining unit 53 is cooled by being brought into contact with the cooling guide surface 54c of the cooling plate 54b made of a metal material or the like by the opposing roller 54a and cooling from the vertical direction. The direction of the film F is changed to the film mounting part 58 in the direction and conveyed. The cooling effect can be increased by making the cooling plate 54b a finned heat sink structure. A part of the cooling plate 54b may have a heat sink structure with fins.

  The cooled film F coming out of the cooling unit 54 is subjected to density measurement by a densitometer 56, conveyed by a conveying roller pair 57, and discharged to a film placement unit 58. The film placing unit 58 can temporarily place a plurality of films F.

  As described above, in the heat development apparatus 40 of FIG. 1, the film F has the BC surface facing the fixed guide surfaces 51d, 52d, 53d in the heated state in the temperature raising portion 50 and the heat retaining portion 53, and the photothermographic material. The coated EC surface is conveyed in an open state. In the cooling unit 54, the film F is conveyed with the BC surface contacting the cooling guide surface 54c and cooled, and the EC surface coated with the heat developing material is opened.

  The film F is transported by the opposing rollers 51a and 52a in the temperature raising unit 50 and the heat retaining unit 53 so that the heating time of the film F is 10 seconds or less.

  As described above, according to the heat development apparatus 40 of FIG. 1, in the temperature raising unit 50 that requires uniform heat transfer, the heating guides 51b and 52b and the plurality of opposed rollers that press the film F against the heating guides 51b and 52b. Since the film F is transported while ensuring contact heat transfer by bringing the film F into close contact with the fixed guide surfaces 51d and 52d by means of 51a and 52a, it is possible to obtain a high-quality image with reduced density unevenness.

  Further, after the temperature is raised to the heat development temperature, the film is transported to the gap d between the fixed guide surface 53d of the heating guide 53b and the curved surface guide 53a by the heat retaining section 53, and in particular without being in close contact with the fixed guide surface 53d. Even if heating is performed in the gap d (direct heat contact with the fixed guide surface 53d and / or heat transfer by contact with the surrounding high-temperature air), the film temperature is predetermined with respect to the developing temperature (for example, 123 ° C.). Within the range (for example, 0.5 ° C.). Thus, regardless of whether the film is conveyed along the wall surface of the heating guide 53b or the curved surface guide 53a in the gap d, the film temperature difference is less than 0.5 ° C., and a uniform heat-retaining state can be maintained. There is almost no risk of density unevenness in the finished film. For this reason, since it is not necessary to provide drive parts, such as a roller, in the heat retention part 53, a score reduction can be achieved.

  Further, the film is guided in the antigravity direction via the heat retaining portion 53, and the curvature guide of the heat retaining portion 53 guides the film toward the cooling portion 54 at a position below the center of curvature P, so the film conveyed in the vertical direction. Compared to the above, it is possible to stabilize the posture of the film being transported, and the volatile matter generated in the heat retaining portion 53 in the gap d becomes a rising airflow and is easily discharged from the heat retaining portion 53, which is preferable.

  Further, since the heating time of the film F is 10 seconds or less, a rapid heat development process can be realized, and the heat retaining portion 53 is configured to be curved and face in the vertical direction. Since the direction of the film F is almost reversed and discharged to the film placement unit 58, the cooling unit 54 has a predetermined curvature according to the apparatus layout, thereby reducing the installation area and the entire apparatus. It becomes possible to respond.

  In conventional large machines, the film was heated to the developing temperature and the heat-retaining function after the temperature was raised had the same heating and transport mechanism as the temperature-raising part. As a result, unnecessary parts were used. However, the increase in the number of parts and the cost increase, and in the conventional small machine, it is difficult to guarantee heat transfer at the time of temperature rise, so there is a problem of uneven density, and it is difficult to guarantee high image quality. According to the present embodiment, the thermal development process is separately performed by the temperature raising unit 50 and the heat retaining unit 53, so that all of these problems can be solved.

  In addition, the film F is heated from the BC side with the temperature raising unit 50 and the heat retaining unit 53 with the EC surface coated with the photothermographic material open, so that the thermal development process can be performed in a rapid process of 10 seconds or less. When performing, since the solvent (moisture, organic solvent, etc.) contained in the film F to be heated and volatilized (evaporated) is dispersed at the shortest distance by opening the EC surface side, the heating time (volatilization time) is short. However, even if there is a part where the contact between the film F and the fixed guide surfaces 51d and 52d is partially poor, the thermal diffusion effect by the PET base on the BC surface causes a contact property. The temperature difference from the good portion is relaxed, and as a result, the density difference hardly occurs, so that the density can be stabilized and the image quality is stabilized. In general, considering the heating efficiency, the EC surface side heating was considered to be better. However, the thermal conductivity of PET of the support base of the film F was 0.17 W / m ° C., and the PET base thickness was 170 μm. Considering the fact that it is before and after, it is preferable that the time delay is slight and can be easily offset by increasing the heater capacity, etc., and the effect of reducing the contact unevenness can be expected.

  Further, the solvent (water, organic solvent, etc.) in the film F is going to volatilize (evaporate) while leaving the heat retaining part 53 and reaching the cooling part 54, but the cooling part 54 also has the film F Since the EC surface is in an open state, the solvent (water, organic solvent, etc.) is not trapped and is volatilized for a longer time, so the image quality (density) is more stable. Thus, the cooling time cannot be ignored during the rapid processing, and is particularly effective for the rapid processing with a heating time of 10 seconds or less.

  Next, rapid processing of the thermal development process in the present embodiment will be described with reference to FIG. FIG. 2A is a graph showing a temperature profile in the first rapid processing method of the thermal development process in the thermal development apparatus 40 of FIG. 1, and FIG. 2B shows a temperature profile in the second rapid processing method. It is a graph.

  In the first rapid processing method, as shown in FIG. 2A, the heating time B is shortened in order to shorten the total film processing time A in the heat developing apparatus 40 of FIG. Therefore, in order to shorten the temperature rising time C to the optimum developing temperature E, the film F is urged by the opposing rollers 51a and 52a in the temperature increasing portion 50 so as to be in close contact with the fixed guide surfaces 51d and 52d. .

  Then, after the film F reaches the optimum development temperature E, the heat retaining portion 53 keeps the film F at the heat development temperature during the heat retention time D. As described above, the heat retaining unit 53 conveys the gap (slit) d without contacting the fixed guide surface 53d without any biasing means such as a counter roller. The rapid cooling in the cooling unit of FIG. 2A can be realized by arranging a heat sink, a cooling fan, or the like in the cooling unit 54.

  As described above, the heating time B (temperature increase time C + heat retention time D) can be shortened from about 14 seconds to 10 seconds or less, and the total processing time A can be shortened.

  In addition, as shown in FIG. 2B, the second rapid processing method has a temperature of 100 ° C. or more at which the development reaction occurs in the film in order to shorten the total processing time A of the film in the thermal development apparatus 40 of FIG. The time B for heating in the temperature range is further shortened. For this purpose, the film F is urged by the opposing roller 52a in the second heating part 52 of the temperature raising part 50 to make the temperature raising time C to the optimum developing temperature E shorter, and is in close contact with the fixed guide surface 51d. I am letting.

  Then, after the film F reaches the optimum development temperature E, the heat retaining portion 53 keeps the film F at the heat development temperature during the heat retention time D. As described above, the heat retaining unit 53 conveys the gap (slit) d without contacting the fixed guide surface 53d without any biasing means such as a counter roller. The rapid cooling in the cooling unit in FIG. 2B can be realized by arranging a heat sink, a cooling fan, or the like in the cooling unit 54.

  As described above, the heating time B (temperature increase time C + heat retention time D) can be shortened from about 14 seconds to 10 seconds or less, and the total processing time A can be shortened.

  Further, in the temperature raising unit 50, as shown in FIG. 2 (b), the film F is preliminarily heated to the heat development start temperature (for example, 100 ° C.) or lower by the first heating unit 51 on the upstream side, and the downstream side The heaters 51c and 52c of the heating units 51 and 52 are independently controlled so as to be heated to the heat development temperature by the second heating unit 52, and heated from room temperature to the heat development start temperature or lower on the upstream side. As a result, the load fluctuation in the heater 52c is particularly less than when the temperature is increased from room temperature to the thermal development temperature. Therefore, the temperature controllability when the temperature is raised to the thermal development temperature by the downstream heater 52c can be improved, and development is accelerated. Temperature fluctuations in the second heating unit 52 in the temperature range can be suppressed, and wrinkle-like deformation of the film due to rapid thermal expansion can be suppressed.

  As described above, according to the thermal development apparatus of the present embodiment, the effect of suppressing the occupation of the installation area and maintaining the image quality can be exhibited, particularly in the case of a small apparatus, from the heating unit in the apparatus. Since the rising airflow is generated and the temperature rises easily, the film storage portion 45 is preferably provided at the bottom portion of the main body, and when the storage portion 45 provided at the bottom portion is used, the occupied area is not increased, which is preferable. . In the film storage unit 45, since the EC surface of the film F is arranged downward, the solvent volatilization from the EC surface tends to be constant in both the uppermost film and the lowermost film, and no foreign matter is deposited. , It is difficult to produce minute white spots.

  As described above, the best mode for carrying out the present invention has been described. However, the present invention is not limited to these, and various modifications are possible within the scope of the technical idea of the present invention. For example, the heat retaining unit 53 of FIG. 1 may be configured as shown in FIG. That is, the heat retaining portion 63 in FIG. 3 is a curved surface composed of a heating guide 63b made of a metal material such as aluminum and having a predetermined curvature and fixed, and a silicon rubber heater closely attached to the back surface of the curved heating guide 63b. Curved heater 63c, and curved guide 63a made of a heat insulating material or the like arranged with a predetermined curvature so as to have a predetermined gap (slit) d with respect to fixed guide surface 63d on the surface of heating guide 63b And having.

  The film is conveyed obliquely downward from the temperature raising unit 60 configured substantially the same as the temperature raising unit 50 of FIG. 1 with respect to the film entrance 63e of the heat retaining unit 63 of FIG. The film entrance 63e and the film discharge port 63f of the heat retaining section 63 are located below the horizontal line passing through the center of curvature P ′ of the heating guide 63b having a predetermined curvature, and the film entrance 63e and the film discharge port are based on the center of curvature P ′. The angle formed by 63f is 90 degrees or more and less than 180 degrees. The film heated (insulated) by the heat retaining unit 53 is guided from the film discharge port 63f of the heat retaining unit 63 toward the cooling unit 64 having substantially the same configuration as the cooling unit 54 of FIG. As described above, in the heat retaining section 64, the film transport direction by the opposing roller 62a of the upstream temperature raising section 60 is set to the separation direction from the center P ′ of the curvature guide, and the heat retaining section 64 The film is guided in the antigravity direction via the heat retaining unit 64 by gradually changing the transport direction from downward to upward in the gap d.

  As described above, since it is not necessary to provide driving parts such as rollers in the heat retaining unit 63 in FIG. 3 as in the heat retaining unit 53 in FIG. 1, the number of points can be reduced, and the antigravity can be achieved via the heat retaining unit 63. Since the film is guided in the direction and the curvature guide of the heat retaining unit 63 guides the film toward the cooling unit 64 at a position below the curvature center P ′, the posture of the film conveyed compared to the film conveyed in the vertical direction Can be stabilized, and the volatile matter generated in the heat retaining portion 63 in the gap d becomes a rising airflow and is easily discharged from the heat retaining portion 63, which is preferable.

It is a side view which shows roughly the principal part of the heat development apparatus by this Embodiment. FIG. 2A is a graph showing a temperature profile in the first rapid processing method of the thermal development process in the thermal development apparatus 40 of FIG. 1, and FIG. 2B shows a temperature profile in the second rapid processing method. It is a graph. It is a principal part side view which shows schematically the modification of the heat retention part of the heat development apparatus of FIG.

Explanation of symbols

40 Heat Development Device 40a Device Housing 45 Film Storage Unit 48 Curved Surface Guide 49a, 49b Conveying Roller Pair 50 Temperature Raising Unit (First Zone)
51 1st heating part 51a Opposing roller 51b Heating guide 51c Heater 51d Fixed guide surface 52 Second heating part 52a Opposing roller 52b Heating guide 52c Heating heater 52d Fixed guide surface 53 Insulating part (second zone)
53a Curved surface guide 53b Heating guide 53c Heating heater 53d Fixed guide surface 53e Film entrance 53f Film discharge port 54 Cooling unit 54a Opposing roller 54b Cooling plate 54c Cooling guide surface 55 Optical scanning exposure unit 63 Heat retaining unit (second zone)
63a Curved surface guide 63b Heating guide 63c Heater 63e Film entrance
63f Film discharge port F Film, sheet film d Gap P, P 'Curvature center of curvature guide

Claims (3)

A heat development apparatus for visualizing a latent image formed on the sheet film by conveying a sheet film coated with a photothermographic material on one side of a supporting substrate while heating the sheet film;
A first zone that is composed of a fixed guide having a heater and a counter-rotatable counter roller that presses the sheet film toward the fixed guide, and is arranged on the upstream side in the conveyance direction; a curvature guide that is different from the curvature guide that has a heater A heating zone having a second zone formed by a guide and having a predetermined gap formed between the curvature guides and disposed downstream in the transport direction;
Cooling means for cooling the sheet film heated by the heating means,
The film entrance position of the curvature guide of the second zone is a position below the center of curvature,
The conveyance direction to the second zone by the counter roller is set to the separation direction from the center of the curvature guide, and the sheet film is guided in the antigravity direction through the second zone by the conveyance force by the counter roller. Configured,
The heat developing apparatus according to claim 2, wherein the curvature guide of the second zone guides the sheet film toward the cooling means at a position below the center of curvature.   2. The heat developing apparatus according to claim 1, wherein an angle formed by the film entrance portion to the second zone and the film discharge portion from the second zone is 90 degrees or less. In the first zone, at least two fixed guides each having a heater are juxtaposed in the transport direction, the upstream side of the fixed guides is heated to the heat development start temperature or lower, and the downstream side is heated to the heat development temperature. The thermal development apparatus according to claim 1, wherein the thermal development apparatus is a thermal development apparatus.

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