JPWO2005106584A1 - Thermal development apparatus and thermal development method - Google Patents

Abstract

Provided are a thermal development apparatus and a thermal development method capable of speeding up a thermal development process while maintaining the same image quality as that of a conventional large machine, and capable of downsizing and cost reduction. This thermal development apparatus visualizes a latent image formed on a film by transporting the film F coated with a photothermographic material on one side of a supporting substrate while heating the film F. A temperature raising section for raising the temperature and a heat retaining section for keeping the sheet film heated to the heat development temperature are provided. The temperature raising section ensures close contact between the film and the heating surface and is heated in the gap by the heat retaining section. Thus, different heating methods were used for the temperature raising part and the heat retaining part.

Description

  The present invention relates to a thermal development apparatus and a thermal development method for visualizing a latent image formed on a sheet film that is a photosensitive thermal development material.

  2. Description of the Related Art In recent years, a thermal development apparatus that obtains a visible image by exposing a photosensitive thermal development material to a latent image by exposing it to a heating body and heating it has become the mainstream in the market. As a configuration of a conventional heat developing apparatus, for example, as described in Patent Document 1, a plurality of rollers and a heating drum are used around a heating drum, and a photosensitive heat developing material is formed by the plurality of rollers. A film comprising the above is urged against a heating drum and conveyed while being heated.

  In such a thermal development apparatus, when a visible image is obtained by heating, density unevenness may occur in the film due to various causes. However, especially when developing a medical image, density unevenness is also an important problem in terms of preventing misdiagnosis. Therefore, prevention of uneven density is an important issue.

  Patent Document 2 below discloses an apparatus that uses a fixed heater divided into three parts instead of the heating drum, slides the BC surface (base surface) of the film on the heater, and conveys the film while heating. To do. Further, Patent Document 3 below discloses a heat developing apparatus that heats a film by passing it through a slit formed on the outer periphery of the drum. Patent Document 4 below discloses a heat development apparatus that is miniaturized by performing exposure, development, and cooling on a single sheet film continuously, and simultaneously performing exposure processing and heat treatment 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 and a large amount of processing capacity by a uniform heating method, but in the latter half of the heating process, the film is heated and transported with more precision than necessary, which reduces the size and number of parts. Cost reduction due to reduction cannot be expected. On the other hand, in the latter case, not only rapid processing but also uniform heating, that is, uniform concentration cannot be achieved.
Japanese National Patent Publication No. 10-500497 JP 2003-287862 A U.S. Pat. No. 3,739,143 JP 2002-162692 A

  In view of the above-described problems of the prior art, the present invention develops a latent image formed on a sheet film by bringing a photosensitive heat-developable material into contact with a heating member and transporting it to obtain a visible image. It is an object of the present invention to provide a thermal development method and a thermal development apparatus that can suppress the occurrence of density unevenness.

  Furthermore, in view of the above-mentioned problems of the prior art, a thermal development apparatus and thermal development capable of speeding up the thermal development process and reducing the size and cost while maintaining the same image quality as a conventional large machine. It aims to provide a method.

  In order to achieve the above object, as a result of intensive investigations, the inventors of the present invention consisted of a temperature raising step in which the heat development process raises the film to the heat development temperature and a heat retention step in which the heated film is kept warm, In the former 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) It was found that the latter heat retention step requires less close contact between the heating member and the film than the former.

  The present invention has been made on the basis of such knowledge, and the thermal development apparatus according to the present invention conveys a sheet film coated with a photothermographic material on one side of a support substrate while heating the sheet, and on the sheet film. A thermal development apparatus for visualizing a formed latent image, wherein a temperature raising unit that raises the temperature of the sheet film to a thermal development temperature, and a temperature of the sheet film that has been heated to the thermal development temperature are maintained (to a thermal development temperature). A temperature maintaining unit), and different heating methods are used for the temperature raising unit and the heat retaining unit.

  The thermal development method according to the present invention is a thermal development method for visualizing a latent image formed on the sheet film by conveying the sheet film coated with the photothermographic material on one side of the support substrate while heating. A temperature raising step for raising the temperature of the sheet film to a heat development temperature, and a temperature keeping step for keeping the temperature of the sheet film heated to the heat development temperature (maintaining at the heat development temperature). A different heating method is used in the heat retaining step.

It is a side view which shows roughly the principal part of the heat development apparatus by 1st Embodiment. It is a side view which shows roughly the principal part of the heat development apparatus by 2nd Embodiment. 3 is a graph showing a temperature profile in a rapid processing method of a thermal development process in the thermal development apparatuses 1 and 40 of FIGS. 1 and 2. FIG. 3 is a side view showing the configuration of the main part of the heat development apparatus used in Example 1. It is a figure which shows the sensit curve (gamma curve) showing the relationship between the exposure amount and density | concentration in Example 1 (a) of rapid processing, and Comparative example 1 (b). It is a figure which shows the sensit curve (gamma curve) showing the relationship between the exposure amount and density | concentration in the comparative example 2 (a) of a normal process, and the comparative example 3 (b). FIG. 5 is a side view showing a main part configuration of a heat development apparatus used in Example 2. In Example 2, the heating plate surface temperature in the slit of FIG. 7, the heat insulating wall surface temperature facing the heating plate surface, and the air temperature in the slit were measured from the start of temperature rise to the thermal development temperature, and the time and temperature It is a graph which shows the relationship. In Example 2, it is a graph which shows the change of each film temperature when the film is passed through the vicinity of the heating plate surface in the slit and when the heat insulating material wall surface is passed. It is a figure which shows the sensit curve (gamma curve) showing the relationship between the exposure amount obtained by Example 2 and the comparative example 4, and a density | concentration. It is a graph which shows the example of the temperature history curve of the photothermographic film which shows the 1st step and 2nd step which were obtained with the heat development apparatus of this Embodiment. FIG. 9 is a diagram illustrating a main part of a heat development apparatus including a heating drum and a counter roller according to a third embodiment. It is a figure which shows schematically the structure for energizing the some opposing roller of FIG. 12 with respect to a heating drum. It is a figure which shows the modification of 3rd Embodiment and shows the principal part of the heat development apparatus by a heating drum and a counter roller. FIG. 10 is a diagram illustrating a main part of a heat development apparatus including a heating plate and a counter roller according to a fourth embodiment. It is a figure which shows the modification of 4th Embodiment and shows the principal part of the heat development apparatus by a heating plate and a counter roller. It is a figure which shows another modification of 4th Embodiment, and shows the principal part of the heat development apparatus by a heating plate and a counter roller. FIG. 10 is a diagram illustrating a main part of a heat development apparatus including a heating plate and a belt according to a fifth embodiment. It is a figure which shows the modification of 5th Embodiment and shows the principal part of the heat development apparatus by a heating plate and a belt.

  The object of the present invention is achieved by the following apparatus and method.

  The heat development apparatus according to the present invention is a heat development apparatus for visualizing a latent image formed on the sheet film by conveying the sheet film coated with the photothermographic material on one side of the support substrate while heating. A heating method comprising: a temperature raising part for raising the temperature of the sheet film to a heat developing temperature; and a heat retaining part for keeping the sheet film heated to the heat developing temperature, and different heating methods for the temperature raising part and the heat retaining part. It is characterized by using.

  According to this thermal development apparatus, the thermal development process can adopt a separate configuration for the temperature raising unit and the heat retaining unit, and the temperature raising unit can achieve close contact between the heating means such as a heating member and the sheet film, thereby causing uneven density. Thermal development process while maintaining high image quality without unevenness of density by using different optimal heating methods for the temperature riser and the heat retention part Thus, it is possible to make the configuration capable of rapid processing, downsizing of the apparatus, and cost reduction.

  In the thermal development apparatus, the temperature raising unit heats the sheet film while pressing the sheet film against a plate heater by a counter roller, and the heat retaining unit is in a slit formed between guides having at least one heater. In the above, the sheet film can be heated. In the temperature raising section, the sheet heater is pressed against and contacted with the plate heater by the opposing roller, so that the plate heater and the sheet film can be brought into close contact with each other. Since it only needs to be conveyed while being heated (insulated) between the slits, there is no need for driving parts for sheet film conveyance, and the size of the apparatus can be reduced and the cost can be reduced without requiring much accuracy of the slit dimensions. .

  In addition, it is possible to configure the engagement time with the sheet film in the temperature raising part and the heat retaining part to be 10 seconds or less, and it is possible to shorten the period of the temperature raising process and the heat retaining process and to quickly process the thermal development process. Is possible.

  In addition, a recess is provided between the temperature raising portion and the heat retaining portion, and the foreign material from the temperature raising portion is configured to enter the recess, so that the film tip is transferred while the temperature raising portion is conveyed. The foreign matter accumulated and moved by the portion can be prevented from being brought into the heat retaining portion, and jamming, scratches, uneven density, etc. can be prevented from occurring on the sheet film.

  In addition, it is preferable that the temperature raising unit and the heat retaining unit are configured to be in contact with the expected support side and open the application surface side of the photothermographic material to heat the sheet film.

  The thermal development method according to the present invention is a thermal development method for visualizing a latent image formed on the sheet film by conveying the sheet film coated with the photothermographic material on one side of the support substrate while heating. A heating method that includes a temperature raising step for raising the temperature of the sheet film to a heat developing temperature and a heat retaining step for keeping the sheet film heated to the heat developing temperature, wherein the heating method is different between the temperature raising step and the heat retaining step. It is characterized by using.

  According to this thermal development method, the thermal development process can be executed separately in the temperature raising step and the heat retaining step, and in the temperature raising step, the heating means such as the heating member and the sheet film are in close contact, There is no need for such close contact, and by using an optimal heating method that is different between the temperature raising process and the heat retaining process, rapid processing of the heat development process, miniaturization of the apparatus, and cost reduction can be achieved while maintaining high image quality. It becomes possible.

  In the heat development method, in the temperature raising step, the sheet film is heated while being pressed against and contacted with a plate heater by a counter roller, and in the heat retaining step, in a slit formed between guides having at least one heater. It is preferable to heat the sheet film. In the temperature raising process, the sheet heater is pressed against and contacted with the plate heater by the opposing roller, so that the plate heater and the sheet film can be brought into close contact with each other. Since it only needs to be conveyed while being heated (insulated) between the slits, there is no need for driving parts for sheet film conveyance, and the size of the apparatus can be reduced and the cost can be reduced without requiring much accuracy of the slit dimensions. .

  In addition, since the engagement time with the sheet film in the temperature raising step and the heat retaining step is 10 seconds or less, the period of the temperature raising step and the heat retaining step can be shortened, and the rapid processing of the heat development process becomes possible.

  In the temperature raising step and the heat retention step, it is preferable to heat the sheet film by opening the coated surface side of the photothermographic material.

  According to the heat development apparatus and the heat development method of the present invention, it is possible to speed up the heat development process and reduce the size and cost while maintaining the image quality equivalent to that of a conventional large machine.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a side view schematically showing a main part of the thermal development apparatus according to the first embodiment.

  As shown in FIG. 1, the thermal development apparatus 1 according to the first 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 surface opposite to the EC surface. A sheet film F (hereinafter referred to as “film”) having a BC surface on the side of the supporting substrate is sub-scanned and conveyed in the direction H, and the optical scanning exposure unit 15 optically scans the laser light L based on the image data. A latent image is formed on the EC surface by exposure, and then the film F is heated from the BC surface side and developed to visualize the latent image.

  The heat development apparatus 1 in FIG. 1 heats the film F on which a 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. And a cooling unit 14 for cooling the heated film F from the BC surface side. The temperature raising unit 10 and the heat retaining unit 13 constitute a heating unit, and the film F is heated to the heat development temperature and held at the heat development temperature.

  The temperature raising unit 10 includes a first heating zone 11 that heats the film F on the upstream side, and a second heating zone 12 that heats the film F on the downstream side.

  The first heating zone 11 includes a planar heating guide 11b made of a metal material such as aluminum and fixed, a planar heating heater 11c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 11b, and a heating A plurality of opposing rollers 11a made of silicon rubber or the like, which is disposed so as to maintain a gap narrower than the film thickness so that the film can be pressed against the fixed guide surface 11d of the guide 11b and whose surface is thermally insulating compared to metal or the like; Have

  The second heating zone 12 includes a planar heating guide 12b made of a metal material such as aluminum and fixed, a planar heating heater 12c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 12b, A plurality of opposed rollers 12a 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 12d of the guide 12b, and whose surface is thermally insulating compared to metal or the like; Have

  The heat retaining unit 13 includes a planar heating guide 13b made of a metal material such as aluminum and fixed, a planar heating heater 13c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 13b, and a heating guide 13b. A guide portion 13a made of a heat insulating material or the like disposed so as to face the fixed guide surface 13d formed on the surface so as to have a predetermined gap (slit) d.

  In the first heating zone 11 of the temperature raising unit 10, the film F conveyed by the conveying roller pair 16 and the like from the upstream side of the temperature raising unit 10 is pressed against the fixed guide surface 11d by each counter roller 11a that is rotationally driven. As a result, the BC surface comes into close contact with the fixed guide surface 11d and is conveyed in the direction H while being heated.

  Similarly, in the second heating zone 12, the film F conveyed from the first heating zone 11 is pressed against the fixed guide surface 12d by each counter roller 12a that is rotationally driven, so that the BC surface is fixed to the fixed guide surface. It is conveyed in the direction H while being in close contact with 11d and being heated.

  A concave portion 17 having an open V shape is provided between the second heating zone 12 of the temperature raising portion 10 and the heat retaining portion 13 so that foreign matter from the temperature raising portion 10 falls into the concave portion 17. It is configured. Thereby, it can prevent that the foreign material from the temperature rising part 10 is carried in into the heat retention part 13, and it can prevent that a jam, a damage | wound, density | concentration unevenness, etc. generate | occur | produce on a film.

  In the heat retaining unit 13, the film F conveyed from the second heating zone 12 is heated (heat retaining) by heat from the heating guide 13b in the gap d between the fixed guide surface 13d of the heating guide 13b and the guide unit 13a. However, the gap d is passed by the conveying force of the opposing roller 12a on the second heating zone 12 side.

  In the cooling unit 14, the film F is further conveyed in the direction H by the facing roller 14a while being cooled by contacting the film F with the cooling guide surface 14c of the cooling plate 14b made of a metal material or the like. In addition, the cooling effect can be increased by making the cooling plate 14b into a heat sink structure with fins. You may further arrange | position the cooling plate of the heat sink structure with a fin in the downstream of the cooling plate 14b.

  As described above, in the heat development apparatus 1 of FIG. 1, the film F has the BC surface facing the fixed guide surfaces 11 d, 12 d, and 13 d provided with the heater in the temperature raising unit 10 and the heat retaining unit 13. It is conveyed with the EC surface coated with the development photosensitive material open. Further, in the cooling unit 14, as indicated by the alternate long and short dash line, the film F is mainly cooled with the BC surface in contact with the cooling guide surface 14c and the EC surface coated with the heat developing material is opened. .

  Moreover, the film F is conveyed by the opposing rollers 11a and 12a so that the time during which the temperature raising unit 10 and the heat retaining unit 13 are conveyed is 10 seconds or less. Therefore, the heating time from temperature increase to heat retention is also 10 seconds or less.

  As described above, according to the heat developing apparatus 1 of FIG. 1, in the temperature raising unit 10 that requires uniform heat transfer, the heating guides 11b and 12b and the plurality of opposed rollers that press the film F against the heating guides 11b and 12b. Since the film F is transported while ensuring contact heat transfer by bringing the film F into close contact with the fixed guide surfaces 11d and 12d by 11a and 12a, the entire surface of the film is heated uniformly and the temperature rises uniformly. Becomes a high-quality image with reduced density unevenness.

  In addition, after the temperature of the film is raised to the heat development temperature, the film is conveyed by the heat retaining unit 13 between the fixed guide surface 13d of the heating guide 13b and the gap d between the guide unit 13a, and particularly on the fixed guide surface 13d. Even if heated in a state where it floats without being in close contact (heated by direct contact with the fixed guide surface 13d and / or heat transferred by contact with the surrounding high-temperature air), the film temperature is the developing temperature (for example, 123). Within a predetermined range (for example, 0.5 ° C.). Thus, even if the film is conveyed along the wall surface of the heating guide 13b or the wall surface of the guide portion 13a in the gap d, the film temperature difference is less than 0.5 ° C., and a uniform heat retaining state can be maintained. The density unevenness in the finished film hardly occurs. For this reason, since it is not necessary to provide driving parts, such as a roller, in the heat retention part 13, a score reduction can be achieved.

  Furthermore, since the heating time of the film F is 10 seconds or less, a rapid heat development process can be realized, and a film transport path extending linearly from the temperature raising unit 10 to the cooling unit 14 is appropriately set according to the apparatus layout. It can be changed, and it becomes possible to cope with downsizing of the installation area and downsizing of the entire apparatus.

  In conventional large-scale machines, the film was heated to the development temperature and the heat-retaining function after the temperature was raised had the same heating and conveying structure 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 first embodiment, it is possible to solve both of these problems by separately executing the heat development process in the temperature raising unit 10 and the heat retaining unit 13.

  Further, by heating the film F from the BC side with the temperature developing unit 10 and the heat retaining unit 13 with the EC surface coated with the photothermographic material open, the thermal development process can be performed in a rapid process of 10 seconds or less. When the EC surface is opened, the solvent (moisture, organic solvent, etc.) contained in the film F that is heated and volatilized (evaporates) is volatilized at the shortest distance by the opening on the EC surface side. Therefore, even if the heating time (the time that can be volatilized) is shortened, it is difficult to be affected by the shortening of the time, and there is a portion where the contact between the film F and the fixed guide surfaces 11d and 12d is partially poor. However, the thermal diffusion effect by the PET surface of the BC surface relaxes the temperature difference from the portion with good contact, 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) even after leaving the heat retaining unit 13 and reaching the cooling unit 14. Since the EC surface is in an open state, the solvent (water, organic solvent, etc.) is not trapped in the emulsion layer and is volatilized for a longer time, so that 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.

<Second Embodiment>
FIG. 2 is a side view schematically showing the main part of the thermal development apparatus according to the second embodiment.

  As shown in FIG. 2, the thermal development apparatus 40 of the second 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 an EC surface. A latent image is formed on the EC surface with the laser light L from the optical scanning exposure unit 55 while transporting (sub-scanning) the film F having the BC surface on the side of the supporting substrate opposite to the surface. The latent image is visualized by heating and developing from the BC surface side, transported upward through the curved transport path, and discharged.

  The heat development apparatus 40 in FIG. 2 picks up and conveys a film storage section 45 that is provided near the bottom of the apparatus housing 40a and stores a large number of unused films F, and the uppermost film F in the film storage section 45. A pickup roller 46 for conveying, a conveyance roller pair 47 for conveying the film F from the pickup roller 46, and a curved surface shape for guiding the film F from the conveyance roller pair 47 and conveying the film F in a substantially reversed direction. A laser beam L based on the image data on the film F between the curved surface guide 48, the conveying roller pair 49a, 49b for conveying (sub-scanning) the film F from the curved surface guide 48, and the conveying roller pair 49a, 49b. , And an optical scanning exposure unit 55 that forms a latent image on the EC surface.

  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. 2, in the thermal development device 40, upward from the bottom of the apparatus housing 40 a, a film storage unit 45, a substrate unit 59 including a conveyance control substrate and an exposure control substrate, and conveyance roller pairs 49 a and 49 b. The warming section 50 and the heat retaining section 53 (upstream side) are arranged in this order, the film storage section 45 is at the lowermost position, and the substrate section 59 is between the temperature raising section 50 and the heat retaining section 53. The heat of the part and the heat of the substrates are ascending airflow and easily move upward, and are 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 zone 51 that heats the film F on the upstream side, and a second heating zone 52 that heats the film F on the downstream side.

  The first heating zone 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 zone 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 configured on a heating guide 53b made of a metal material such as aluminum and fixed, a planar heating heater 53c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 53b, and a surface of the heating guide 53b. And a guide portion 53a having a heat insulating material on the surface opposite to the film passage surface, which is disposed so as to have a predetermined gap (slit) d with respect to the fixed guide surface 53d. The heat retaining unit 53 is configured in a planar manner on the temperature raising unit 50 side continuously with the second heating zone 52, and is configured in a curved surface with a predetermined curvature from the middle toward the upper part of the apparatus.

  In the first heating zone 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 each counter roller 51a that is 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 zone 52, the BC surface is fixed to the fixed guide surface 51d by pressing the film F conveyed from the first heating zone 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.

  As in FIG. 1, a concave portion opened in a V shape may be provided between the second heating zone 52 and the heat retaining unit 53 of the temperature raising unit 50. As a result, the foreign matter from the temperature rising part 50 can be prevented from being brought into the heat retaining part 53.

  In the heat retaining portion 53, the film F conveyed from the second heating zone 52 is heated (heat retained) by the heat from the heating guide 53b in the gap d between the fixed guide surface 53d of the heating guide 53b and the guide portion 53a. However, it passes through the gap d by the conveying force of the opposing roller 52a on the second heating zone 52 side. At this time, the film F is conveyed while gradually changing the direction from the horizontal direction to the vertical direction in the gap d, and heads toward the cooling unit 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 14c 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. 2, the film F has the BC surface facing the fixed guide surfaces 51d, 52d, 53d in the heating 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.

  Moreover, the film F is conveyed by the opposing rollers 51a and 52a so that the time for which the temperature raising unit 50 and the heat retaining unit 53 are conveyed is 10 seconds or less. Therefore, the heating time from temperature increase to heat retention is also 10 seconds or less.

  As described above, according to the heat development apparatus 40 of FIG. 2, 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 conveyed while ensuring contact heat transfer by bringing the film F into close contact with the fixed guide surfaces 51d and 52d by 51a and 52a, the entire surface of the film is heated uniformly and the temperature rises uniformly. Becomes a high-quality image with reduced density unevenness.

  Further, after the film is heated to the heat development temperature, it is conveyed by the film heat retaining portion 53 between the fixed guide surface 53d of the heating guide 53b and the gap d between the guide portion 53a, and in particular, in close contact with the fixed guide surface 53d. Even when heated in a floating state without direct contact (heated by direct contact with the fixed guide surface 53d and / or heat transferred by contact with the surrounding high-temperature air), the film temperature remains at the developing temperature (for example, 123 ° C). ) Within a predetermined 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.

  Furthermore, since the heating time of the film F can be 10 seconds or less, a rapid heat development process can be realized, and the heat retaining portion 53 extending in the horizontal direction from the temperature raising portion 50 becomes a curved surface in the middle and extends in the vertical direction. Since the film F is discharged to the film mounting unit 58 with the direction of the film F being substantially reversed by the cooling unit 54, the cooling unit 54 has a predetermined curvature according to the apparatus layout. It is possible to cope with downsizing of the installation area and downsizing of the entire device.

  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 second embodiment, as in the first embodiment, the thermal development process is performed separately in the temperature raising unit 50 and the heat retaining unit 53, thereby eliminating all of these problems. Can do.

  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 the EC surface is opened, the solvent (moisture, organic solvent, etc.) contained in the film F that is heated and volatilized (evaporates) is volatilized at the shortest distance by the opening on the EC surface side. Therefore, even if the heating time (the time that can be volatilized) is shortened, it is difficult to be affected by the shortening of the time, and there is a part where the contact between the film F and the fixed guide surfaces 51d and 52d is partially poor. However, the thermal diffusion effect by the PET surface of the BC surface relaxes the temperature difference from the portion with good contact, 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 that the image quality 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 first and second embodiments will be described with reference to FIG. FIG. 3 is a graph showing a temperature profile in the rapid processing method of the thermal development process in the thermal development apparatuses 1 and 40 of FIGS.

  In this rapid processing method, as shown in FIG. 3, the heating time B is shortened in order to shorten the total film processing time A in the heat developing apparatuses 1 and 40 of FIGS. For this purpose, in order to shorten the temperature raising time C to the optimum developing temperature E, the film F is urged by the opposing rollers 11a, 12a, 51a, 52a in the temperature raising portions 10, 50, and the fixed guide surfaces 11d, 12d, In close contact with 51d and 52d.

  After the film F reaches the optimum development temperature E, the film F is held at the heat development temperature in the heat retaining portions 13 and 53 for the heat retaining time D. In the heat retaining units 13 and 53, as described above, it is not essential that the gap (slit) d is in close contact with the fixed guide surfaces 13d and 53d without an urging means such as a counter roller. It may be transported. 3 can be realized by arranging a heat sink, a cooling fan, or the like in the cooling units 14 and 54.

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

<Example 1>
Next, the effect of heating the BC surface and opening the EC surface in the rapid process heating process will be described according to the first embodiment. The heat development apparatus shown in FIG. 4 was used in an experiment and configured as follows.

  As a heating system, a silicon rubber heater was attached to the back surface of an aluminum plate having a thickness of 10 mm to form a plate-shaped heating plate. On the guide surface of the heating plate, a silicon rubber roller having a diameter of 12 mm and an effective conveyance length of 380 mm provided with a silicon rubber layer having a thickness of 1 mm is arranged on the surface so that the linear pressure is about 8 gf / cm. The film coated with the material was pressed and conveyed while the BC surface was in contact with the heating plate. The conveyance length of the heating plate is 210 mm.

  As a cooling system, an aluminum plate having a thickness of 10 mm is used as the first to third cooling plates, and the first and second cooling plates are each provided with a silicon rubber heater so that the cooling temperature can be controlled, and the third cooling plate is provided. A heat sink in which 21 fins having a thickness of 0.7 mm, a height of 35 mm, and a depth of 390 mm were arranged at a pitch of 4 mm was joined to the back surface of the aluminum plate. A silicon rubber roller having a diameter of 12 mm and an effective conveyance length of 380 mm is disposed on the first to third cooling plates at a surface pressure of a silicon rubber layer having a thickness of 1 mm, and conveyed while pressing the film with a linear pressure of about 8 gf / cm. did. The conveyance lengths of the first to third cooling plates are 60 mm, 105 mm, and 105 mm, respectively.

  The conveyance speed was changed to 15.1 mm / s during normal processing and 21.2 mm / s during rapid processing. The temperatures of the first and second heating plates are 100 ° C. and 123 ° C., respectively, the temperature of the first cooling plate is 110 ° C., the temperature of the second cooling plate is 90 ° C., and the temperature of the third cooling plate is 30 to 30 ° C. The temperature was 60 ° C. A gap of 2 mm was provided between the heating plates and between the heating plate and the cooling plate in order to suppress heat transfer between the plates.

  As the heat developing film, SD-P manufactured by Konica Minolta Co., Ltd., which is an organic solvent-based heat developing film as disclosed in JP-A No. 2004-102263, was used.

The film was allowed to acclimate by leaving it in three environments of normal (25 ° C., 50% RH), high humidity (25 ° C., 80% RH), and low humidity (25 ° C., 20% RH). (By doing this, the moisture content in the film also changes.)
Using these films, the thermal development process was performed in the thermal development apparatus of FIG. That is, as Example 1, the emulsion layer surface (EC surface) side coated with the coating solution was released and pressed with a silicon rubber roller and conveyed while the BC surface was in contact with the heating plate, and the heating time B in FIG. Then, heat development was performed (EC surface opening / BC surface heating / rapid processing).

  As Comparative Example 1, heat development was performed under the same conditions as in Example 1 except that the film was turned upside down and heated on the BC side and EC side (BC side opening, EC side heating, and rapid processing).

  As Comparative Example 2, heat development was performed under the same conditions as in Example 1 except that the EC surface side was opened and heated on the BC surface side, and the normal processing was performed with a heating time B of 14 seconds (EC surface open / BC Surface heating / normal treatment).

  As Comparative Example 3, heat development was performed under the same conditions as in Example 1 except that the BC surface side was opened and the EC surface side was heated, and the normal processing was performed with a heating time B of 14 seconds (BC surface opening / EC Surface heating / normal treatment).

  FIGS. 5A and 5B are diagrams showing sensit curves (γ curves) representing the relationship between the exposure amount and the density in Example 1 and Comparative Example 1 of rapid processing. FIGS. 6A and 6B are diagrams showing sensit curves (γ curves) representing the relationship between the exposure amount and the density in Comparative Examples 2 and 3 of normal processing.

  As shown in FIGS. 6 (a) and 6 (b), in the conventional normal processing, there was no significant difference in absolute concentration and sensit curve for both the BC surface heating and EC surface heating regardless of normal, high humidity, and low humidity.

  On the other hand, as shown in FIGS. 5 (a) and 5 (b), in the case of rapid processing, the sensit curve changed considerably in the EC surface heating of Comparative Example 1 due to normal, high humidity, and low humidity, whereas the BC surface of Example 1 Heating did not change so much, it varied only about Comparative Example 3, and was maintained at the same level as conventional normal processing. This is because the residual solvent (moisture, organic solvent, etc.) in the film that is heated and volatilized (evaporates) is dispersed at the shortest distance by setting the EC surface open and BC surface heating, so the heating time (volatilization time) This is considered to be because it is difficult to be affected by the time reduction even if becomes shorter. Further, since the EC surface of the film is in an open state even in the cooling system, moisture or the like is not trapped, and it is volatilized for a longer time, which is considered to be less susceptible to the time reduction.

<Example 2>
Next, the effect of heating the gap (slit) in the heat retaining portion will be described with reference to Example 2. In this example, the heat development apparatus shown in FIG. 7 was used in the experiment. In this thermal developing apparatus, the rubber roller is omitted on the downstream side of the heating system in FIG. 4 to form a third heating plate, and the film passage portion is slit-shaped by covering with a heat insulating material to perform slit heating. The slit interval between the third heating plate and the heat insulating material was 3 mm.

  Measure the surface temperature of the heating plate in the slit of FIG. 7, the temperature of the heat insulating material wall facing the surface of the heating plate, and the temperature of the air in the slit from the start of raising the temperature to the thermal development temperature, and show the relationship between the time and temperature It is shown in FIG.

  FIG. 9 shows changes in the film temperature when the film is passed through the vicinity of the surface of the heating plate in the slit and when the vicinity of the wall surface of the heat insulating material is passed.

  As can be seen from FIG. 8, after reaching the heat development temperature, the wall surface temperature of the heat insulating material and the air temperature in the slit are almost constant and almost coincide with each other, and are about 3 ° C. lower than the surface temperature of the heating plate.

  As can be seen from FIG. 9, when the slit interval is 3 mm or less and the heat retention time is 8 seconds or less, when the film is passed in the vicinity of the surface of the heating plate in the slit, the film temperature is slightly lower than the developing temperature of 123 ° C. When passed near the wall surface of the heat insulating material, the film temperature is lower than when passing near the surface of the heating plate, but both are less than 0.5 ° C with respect to the development set temperature (123 ° C). Therefore, the influence on the concentration is within a negligible range. Therefore, the slit gap of the heat retaining portion can be within 3 mm, and the tolerance for the curvature error and the mounting accuracy at the time of processing of both guides becomes large, resulting in a great increase in design freedom.

  As Example 2, the heat development process was performed using the heat development apparatus of FIG. FIG. 10 shows a sensit curve (γ curve) representing the relationship between the exposure amount and density obtained at this time. In addition, a thermal development process was performed under the same conditions as in Example 2 except that the thermal development apparatus of FIG. 4 was used as Comparative Example 4, and a sensit curve (γ curve) representing the relationship between the exposure amount and density obtained at this time. Is also shown in FIG.

  As can be seen from FIG. 10, when the film reaches the heat development temperature, the film is heated in close contact with the surface of the heating plate with a counter roller (Comparative Example 4), and when the film is heated in the slit ( When compared with Example 2), there was almost no difference in the sensit curve, and almost the same result could be obtained.

<Third Embodiment>
FIG. 12 shows the third embodiment, and is a view showing the main part of a heat development apparatus using a heating drum and a counter roller. FIG. 13 is a diagram schematically showing a configuration for urging the plurality of opposing rollers of FIG. 12 against the heating drum.

  The heat development apparatus shown in FIG. 12 is energized and opposed so as to abut on a metal cylindrical heating drum 111 having a planar electric heater 119 disposed therein and an outer peripheral surface 120 of the heating drum 111. A heat developing unit 110 having a plurality of relatively small-diameter metal facing rollers 112 to 118 arranged rotatably, and a photosensitive heat developing material arranged below the heat developing unit 110 based on image data. A photothermographic film (hereinafter also abbreviated as “film”) F, and an optical scanning unit 190 for forming a latent image.

  The cylindrical heating drum 111 is set so that its width direction (perpendicular to the paper surface in FIG. 12) size matches the width direction size of the film F, and the outer peripheral surface 120 is moved in the width direction by the inner surface-shaped electric heater 119. It is heated uniformly and is rotationally driven in the rotational direction R.

  As shown in FIG. 13, the opposing rollers 112 to 118 extend along the width direction of the heating drum 111, and are rotatably supported by bearings 112 b to 118 b on both ends of the heating drum 111. A plurality of coil springs 112a to 118a as urging members are arranged between the bearings 112b to 118b of the opposing rollers 112 to 118 and the fixed portion on the apparatus housing side, respectively. Thereby, each opposing roller 112-118 is urged | biased by the outer peripheral surface 120 of the heating drum 111 with the coil springs 112a-118a.

  In this case, each biasing force of the coil springs 112a, 113a, 114a of the most upstream counter roller 112 and the adjacent counter rollers 113, 114, for example, increases the spring constant so that the counter rollers 115- It is stronger than the 118 coil springs 115a to 118a.

  The film F is sent in the upward conveyance direction V in FIG. 12 and sent to the heating drum 111, and the opposing rollers 112 are sandwiched between the outer peripheral surface 120 of the heating drum 111 and the opposing rollers 112 to 118. It is heated while receiving a biasing force from ˜118, and is conveyed by the rotation of the heating drum 111 in the rotation direction R, and further conveyed between the most downstream facing roller 118 and the heating drum 111 in the conveyance direction S. ing. At this time, the film F is urged relatively strongly by the upstream facing rollers 112 to 114 by the coil springs 112 a to 114 a whose urging force is increased at the beginning of feeding to the heating drum 111. The outer peripheral surface 120 is closely attached.

  The optical scanning unit 190 in FIG. 12 forms a latent image on the photothermographic film F based on image data by performing main scanning in the direction perpendicular to the paper surface with the laser light L while carrying the subscanning conveyance of the photothermographic film F. . In FIG. 12, while the latent image is formed on the film F by the optical scanning unit 190, the leading end side of the film F is heated and developed by the thermal development unit 110, and the cycle time is shortened. The film having the latent image formed thereon may be heated by the heat developing unit 110.

  A specific configuration example of the heating drum 111 and the opposed rollers 112 to 118 will be described. The heating drum 111 is formed by forming an elastic layer made of silicon rubber on the outer peripheral surface of an aluminum cylindrical tube having a diameter of 140 mm. A smooth surface layer formed by coating with a fluorine compound may be formed thereon, and a planar electric heater 119 may be attached to the inner peripheral surface. The rubber hardness of the silicon rubber of the elastic layer is preferably 50 to 60 ° in Shore A hardness.

  Further, the opposing rollers 112 to 118 can be made of, for example, steel cylinders having a diameter of 8 to 12 mm. For example, the upstream opposing rollers 112 to 114 having a diameter of 12 mm having a large heat storage capacity are used as coils. The biasing force to the heating drum 111 by the springs 112a to 114a and each counter roller's own weight component is preferably in the range of 7 to 20 gf / cm, and the counter rollers 115 to 118 on the downstream side are alternately 10 mm and 8 mm in diameter. The biasing force from each counter roller to the heating drum 111 by the coil springs 115a to 118a and the self-weight component of each counter roller is preferably in the range of 1 to 7 gf / cm.

  The operation of the heat development apparatus of FIGS. 12 and 13 will be described with reference to FIG. First, a latent image is formed by exposing and scanning the film F with laser light L based on the image data in the optical scanning unit 190 to which the photothermographic film F has been conveyed.

  When the film F on which the latent image is formed is transported in the transport direction V of FIG. 12 and sent between the outer peripheral surface 120 of the heating drum 111 and the uppermost counter roller 112, the rotating heating drum 111 In sequence, the paper is conveyed from the opposing roller 112 to the adjacent opposing rollers 113 and 114. During this time, the film F starts to contact the outer peripheral surface 120 heated by the electric heater 119 of the heating drum 111 and is heated, thereby reaching the vicinity of the developing temperature T as in the first step S01 of FIG. However, until the temperature reaches the vicinity of the developing temperature T, the film F comes into closer contact with the outer peripheral surface 120 by the coil springs 112a to 114a whose urging force is strengthened by the upstream facing rollers 112 to 114. Therefore, the amount of heat transfer from the outer peripheral surface 120 to the film F can be maintained substantially constant.

  Next, the film F that has reached the developing temperature T is further rotated by the heating drum 111 while receiving a biasing force from each of the opposing rollers 115 to 118 while being sandwiched between the outer peripheral surface 120 and each of the opposing rollers 115 to 118. The film F is conveyed by rotation in the direction R. During this time, the film F is heated while being maintained at the developing temperature T as shown in step S02 of FIG. 11, and from between the most downstream counter roller 118 and the heating drum 111. A film that has been transported in the transport direction S and developed as a visible image by developing the latent image is output.

  As described above, if the contact between the film F and the outer peripheral surface 120 of the heating drum 111 is insufficient, density unevenness is likely to occur in the first step S01. Since the amount of heat transfer from the outer peripheral surface 120 to the film F can be maintained almost constant, the occurrence of density unevenness can be effectively suppressed.

  Further, since the film F is in close contact with the outer peripheral surface 120 by the coil springs 112a to 114a whose urging force is strengthened by the upstream facing rollers 112 to 114, the film F is in close contact with the entire width of the film F, and the density is reduced. It becomes difficult to do.

  Further, in the second step S02 which has little influence on the occurrence of density unevenness, there is no need for particularly close contact between the film F and the outer peripheral surface 120. Therefore, the coil springs 115a to 118a are separated from the gravity component of each counter roller. At the same time, it is sufficient that the urging force with respect to each of the opposing rollers can be obtained, for example, within the range of 1 to 7 gf / cm.

  There are also devices that preheat the film upstream of the heat development section of the heat development device to reduce the variation in the development temperature, but this increases the size and cost of the device. In the heat developing apparatus of this form, the size and cost of the apparatus hardly increase.

  In FIG. 13, the urging force of the coil springs 112a, 113a, 114a of the opposing rollers 112, 113, 114 is increased, but the urging force is increased according to the time to reach the developing temperature T in step S01 of FIG. The opposing roller can be appropriately set. For example, the urging force of the coil springs 112a and 113a of the opposing rollers 112 and 113 may be increased, or the urging force of the coil springs 112a to 115a of the opposing rollers 112 to 115 may be increased. Good.

  Further, the developing temperature T in FIG. 11 can be set as appropriate according to the type of the photothermographic film F, but can be set within a range of 100 to 200 ° C., for example, in the vicinity of the developing temperature T in the first step S01. Can be set, for example, to a developing temperature T ± 1 ° C.

  Next, another configuration example of the heat developing apparatus using the heating drum and the counter roller will be described with reference to FIG. FIG. 14 shows a modification of the first embodiment, and is a diagram showing a main part of a heat development apparatus including a heating drum and a counter roller.

  In the thermal development apparatus shown in FIG. 14, upstream counter rollers 121, 122, and 123 among a plurality of counter rollers 121 to 126 arranged to face the heating drum 111 are arranged in the circumferential direction of the outer peripheral surface 120 of the heating drum 111. The counter rollers 124 to 126 on the downstream side are arranged relatively closely and roughly. That is, while the counter rollers 121 and 122 and the counter rollers 122 and 123 are relatively close to each other in the circumferential direction, the counter rollers 123 and 124, the counter rollers 124 and 125, and the counter rollers 125 and 126 are relatively spaced apart in the circumferential direction.

  Each of the opposing rollers 121 to 126 is urged by an urging member made of a coil spring or the like as in FIG. 13 so as to be pressed against the outer peripheral surface 120 of the heating drum 111 with the film F interposed therebetween.

  14, the photothermographic film F having a latent image formed thereon is conveyed in the conveying direction V in FIG. 14, and the outermost surface 120 of the heating drum 111 and the uppermost stream in the same manner as in FIG. When fed between the opposing rollers 121, the heated drum 111 is sequentially conveyed from the opposing roller 121 to the adjacent opposing rollers 122, 123 by the rotating heating drum 111. During this time, the film F is on the upstream side. Since the opposed rollers 121 to 123 are densely arranged in the circumferential direction which is the film traveling direction, the opposed rollers 121 to 123 are heated in close contact with the heated outer peripheral surface 120 of the heating drum 111.

  Accordingly, similarly to FIG. 12, in the first step S01 of FIG. 11, the film F and the outer peripheral surface 120 can be brought into closer contact, and the amount of heat transfer from the outer peripheral surface 120 to the film F is substantially constant. Therefore, the occurrence of uneven density can be effectively suppressed.

  Further, since the film F is in close contact with the outer peripheral surface 120 by the upstream facing rollers 121 to 123 that are densely arranged, the film F is in close contact with the entire width of the film F, and the density is hardly lowered. Further, in the second step S02, which has little influence on the occurrence of density unevenness, there is no need for particularly close contact between the film F and the outer peripheral surface 120. Therefore, the opposed rollers 124 to 126 on the downstream side are arranged roughly. It is good.

  In order to obtain further adhesion between the film F and the outer peripheral surface 120 in the first step S01 of FIG. 11, the biasing force of each coil spring of the upstream facing rollers 121 to 123 as shown in FIG. May be stronger than the downstream side. In this case, the biasing force of only the coil spring of the opposing roller 121 or each coil spring of the opposing rollers 121 and 122 may be increased.

<Fourth embodiment>
FIG. 15 is a diagram showing a main part of a heat development apparatus including a heating plate and a counter roller according to a fourth embodiment.

  The heat development apparatus of FIG. 15 has planar electric heaters 131b, 132b, and 133b as heat sources for heating the film F, and is formed linearly and substantially flat in the conveyance direction H of the film F. A plurality of heating plates 131, 132, 133 having guide surfaces 131 a, 132 a, 133 a, and a rotational drive for conveying in the conveying direction H while sandwiching the film F between the heating plates 131, 132, 133. A plurality of counter rollers 134 to 136, a plurality of counter rollers 137 to 139, and a plurality of counter rollers 140 to 142 are provided. Although not shown, an optical scanning unit similar to that shown in FIG. 12 is disposed on the upstream side of the heating plate 131, and a latent image is formed on the film F based on the image data.

  The plurality of heating plates 131, 132, 133 are arranged in this order from the upstream side in the transport direction H. The guide surfaces 131a, 132a, 133a of the heating plates 131-133 are uniformly heated in the width direction (direction perpendicular to the conveying direction H on the guide surface) by the internal planar electric heaters 131b, 132b, 133b, respectively. Then, the film F conveyed in the conveying direction H in order through the guide surfaces 131a, 132a, and 133a is heated, and the latent image formed on the film F is developed and visualized. In addition, it is preferable that each guide surface 131a-133a of each heating plate 131-133 consists of metal materials, such as aluminum, and coats the fluorine compound on the surface.

  A plurality of opposing rollers 134 to 142 provided on the respective heating plates 131 to 133 extend in the width direction (perpendicular to the paper surface in FIG. 15) perpendicular to the conveying direction H of the respective guide surfaces 131a to 133a. Are biased toward the guide surfaces 131a to 133a by coil springs 134a to 142a via bearings 134b to 142b. Each of the opposing rollers 137 to 142 can be composed of a rubber roller such as silicon rubber.

  In this case, each biasing force of the coil springs 134a to 136a of the plurality of opposing rollers 134 to 136 disposed on the most upstream heating plate 131 increases the spring constant, for example, so that the opposing rollers 137 to 142 on the downstream side thereof. The coil springs 137a to 142a are stronger.

  The urging force from each counter roller to each heating plate is generated not only by each coil spring but also by the weight of each counter roller. Therefore, the urging force may be changed by changing the weight of each counter roller. Further, the coil spring may be omitted and adjustment may be performed by generating an urging force only by the weight of the opposing roller. In this case, by improving the finishing accuracy of each opposing roller, the film of each opposing roller in the width direction is adjusted. Uniform contact can be improved.

  The biasing forces of the opposing rollers 134 to 136 with respect to the heating plate 131 are preferably in the range of 7 to 20 gf / cm, and the biasing forces of the opposing rollers 137 to 142 with respect to the heating plates 132 and 133 on the downstream side thereof are It is preferably in the range of 1 to 7 gf / cm.

  The operation of the heat development apparatus of FIG. 15 will be described with reference to FIG. After forming a latent image on the photothermographic film F in the same manner as in FIG. 12, the film F is transported in the horizontal transport direction H in FIG. 15, and the guide surface 131a of the heating plate 131 and the uppermost counter roller. When the sheet is fed between the counter roller 134 and the counter roller 135, the rotating counter roller is sequentially transported from the counter roller 134 to the adjacent counter rollers 135 and 136. During this time, the film F starts to come into contact with the guide surface 131a heated by the electric heater 131b of the heating plate 131 and is heated, thereby reaching the vicinity of the developing temperature T as in the first step S01 of FIG. However, until the temperature reaches the vicinity of the developing temperature T, the film F comes into closer contact with the guide surface 131a by the coil springs 134a to 136a whose urging force is strengthened by the upstream facing rollers 134 to 136. Therefore, the amount of heat transfer from the guide surface 131a to the film F can be maintained substantially constant.

  Next, the film F that has reached the developing temperature T is further urged by the opposing rollers 137 to 142 while being sandwiched between the guide surfaces 132a and 133a and the opposing rollers 137 to 142 by the heating plates 132 and 133. In the meantime, the film F is heated while being maintained at the developing temperature T as shown in step S02 of FIG. 11, and between the counter roller 142 and the heating plate 133 on the most downstream side. The film F is transported in the transport direction H ′ from which the latent image is developed to become a visible image.

  As described above, if the contact between the film F and the guide surface 131a of the heating plate 131 is insufficient, unevenness in density tends to occur in the first step S01, and the gap between the film F and the guide surface 131a is more dense. Since the amount of heat transfer from the guide surface 131a to the film F can be maintained almost constant, the occurrence of uneven density can be effectively suppressed.

  Further, since the film F is in close contact with the guide surface 131a by the coil springs 134a to 136a whose urging force is strengthened by the upstream facing rollers 134 to 136, the film F is in close contact with the entire width of the film F, resulting in a decrease in density. It becomes difficult to do.

  Further, in the second step S02 that has little influence on the occurrence of density unevenness, there is no need for particularly close contact between the film F and the guide surfaces 132a and 133a. Along with the components, for example, it is sufficient to obtain an urging force with respect to each of the opposing rollers, for example, within the range of 1 to 7 gf / cm described above.

  Next, a modification of FIG. 15 will be described with reference to FIG. FIG. 16 shows a modification of the fourth embodiment, and is a view showing a main part of a heat development apparatus using a heating plate and a counter roller.

  In the heat development apparatus shown in FIG. 16, a plurality of opposing rollers 171 to 174 are arranged close to each other in close proximity to the conveying direction H in order from the upstream side so as to face the most upstream heating plate 131, and the downstream heating plate is arranged. A single counter roller 175 is disposed at 132, and a single counter roller 176 is disposed at the heating plate 133 on the downstream side. In other words, the counter rollers 171 and 172, the counter rollers 172 and 173, and the counter rollers 173 and 174 are relatively close to the conveying direction H, respectively, while the counter rollers 174 and 175 are opposed to each other. The rollers 175 and 176 are relatively separated from each other in the transport direction H.

  Each of the opposing rollers 171 to 176 is urged by an urging member made of a coil spring or the like as in FIG. 15 so as to be pressed against the guide surfaces 131a to 133a of the heating plates 131 to 133 across the film F. .

  According to the heat development apparatus of FIG. 16, the photothermographic film F having a latent image formed thereon is conveyed in the conveyance direction H of FIG. 16, and between the guide surface 131a of the heating plate 131 and the uppermost counter roller 171. Then, each of the rotating counter rollers is sequentially conveyed from the counter roller 171 to the adjacent counter rollers 172, 173, and 174. During this time, the film F is fed to the upstream counter roller 171. ˜174 are densely arranged in the conveyance direction H of the film F, and are heated in close contact with the heated guide surface 131a of the heating plate 131.

  Therefore, similarly to FIG. 15, in the first step S01 of FIG. 11, the film F and the guide surface 131a can be brought into closer contact, and the heat transfer amount from the guide surface 131a to the film F is substantially constant. Therefore, the occurrence of uneven density can be effectively suppressed.

  Further, since the film F is in close contact with the guide surface 131a by the upstream-side opposing rollers 171 to 174 arranged densely, the film F is in close contact with the entire width of the film F, and a decrease in density is less likely to occur. Further, in the second step S02 that has little influence on the occurrence of density unevenness, there is no need for particularly close contact between the film F and the guide surfaces 132a and 133a, so that the opposed rollers 175 and 176 on the downstream side are roughly arranged. You may do it.

  In order to obtain further close contact between the film F and the guide surface 131a in the first step S01 in FIG. 11, the coil springs and / or the upstream opposing rollers 171 to 174 as shown in FIG. The biasing force due to the weight of each counter roller may be stronger than that on the downstream side. In this case, the urging force of the opposing rollers 171, 172 or the opposing rollers 171, 172, 173 may be increased only for the opposing roller 171.

  Next, another modification of FIG. 15 will be described with reference to FIG. FIG. 17 shows another modification of the fourth embodiment, and is a view showing a main part of a heat development apparatus using a heating plate and a counter roller.

  The heat development apparatus shown in FIG. 17 is opposed to the gap g1 between the plurality of facing rollers 134 to 136 and the guide surface 131a disposed facing the most upstream heating plate 131, and the intermediate heating plate 132. A gap g2 between the plurality of opposed rollers 137 to 139 and the guide surface 132a, and a gap g3 between the plurality of opposed rollers 140 to 142 arranged to face the most downstream heating plate 133 and the guide surface 133a. , The upstream side g1 is set narrower than the downstream side gaps g2 and g3.

  The gaps g1, g2, and g3 can be set by determining the positions of the opposing rollers 134 to 142 with respect to the guide surfaces 131a to 133a, and are set smaller than the thickness of the film F.

  17, the photothermographic film F having a latent image formed thereon is conveyed in the conveying direction H in FIG. 16, and between the guide surface 131a of the heating plate 131 and the uppermost counter roller 134. In this case, the film F is sequentially conveyed from the opposing roller 134 to the adjacent opposing rollers 135 and 136 by the rotating opposing rollers. During this time, the film F is fed to the upstream opposing rollers 134 to 136. Is disposed closer to the guide surface 131a with a narrower gap g1, and is heated in close contact with the heated guide surface 131a of the heating plate 131.

  Therefore, similarly to FIG. 15, in the first step S01 of FIG. 11, the film F and the guide surface 131a can be brought into closer contact, and the heat transfer amount from the guide surface 131a to the film F is substantially constant. Therefore, the occurrence of uneven density can be effectively suppressed.

  In addition, since the film F is in close contact with the guide surface 131a by the upstream facing rollers 134 to 136 that are arranged narrowly with respect to the guide surface 131a, the film F is in close contact with the entire width of the film F, and the decrease in density is less likely to occur. . Further, in the second step S02 that has little influence on the occurrence of density unevenness, there is no need for particularly close contact between the film F and the guide surfaces 132a and 133a. Therefore, the gaps g2 and g3 are relatively large on the downstream side. It may be.

<Fifth embodiment>
FIG. 18 shows a fifth embodiment, and is a diagram showing a main part of a heat development apparatus using a heating plate and a belt.

  In the heat development apparatus shown in FIG. 18, an endless belt 150 is arranged so as to face the guide surfaces 131a, 132a, 133a of the heating plates 131, 132, 133 arranged in order from the upstream side. The endless belt 150 is stretched around a plurality of pulleys 151 to 154, and is moved endlessly in the direction A, for example, when the pulley 151 is rotationally driven.

  The endless belt 150 is close to the guide surfaces 131a, 132a, and 133a between the pulleys 151 and 152, and moves in the direction A so that the film F is sandwiched between the guide surfaces 131a to 133a. It is designed to carry in the carrying direction H.

  On the relatively upstream side between the pulleys 151 and 152, press rollers 155 and 156 that press the endless belt 150 against the guide surfaces 131a and 132a are arranged. The pressing rollers 155 and 156 may be urged toward the guide surfaces 131a and 132a by an urging member such as a coil spring, as in FIG.

  18, the photothermographic film F having a latent image formed thereon is conveyed in the conveying direction H in FIG. 18, and sent between the guide surface 131a of the heating plate 131 and the endless belt 150. Then, the endless belt 150 moving in the direction A is sequentially conveyed from the guide surface 131a to the guide surfaces 132a and 133a. During this time, the film F is conveyed by the upstream pressing rollers 155 and 156. Since 150 is pressed against the guide surfaces 131a and 132a, it is heated in close contact with the heated guide surfaces 131a and 132a of the heating plates 131 and 132.

  Accordingly, in the first step S01 of FIG. 11, the film F and the guide surfaces 131a and 132a can be brought into closer contact with each other, and the amount of heat transfer from the guide surfaces 131a and 132a to the film F can be maintained almost constant. The occurrence of uneven density can be effectively suppressed.

  Further, since the film F is in close contact with the guide surfaces 131a and 132a by the upstream pressing rollers 155 and 156, the film F is in close contact over the entire width of the film F, and it is difficult for a decrease in density to occur. Further, in the second step S02 that has little influence on the occurrence of density unevenness, there is no need for particularly close contact between the film F and the guide surface 133a, so that the pressing roller can be omitted on the downstream side. Note that the number and arrangement position of the pressing rollers can be changed as appropriate.

  Next, a modification of FIG. 18 will be described with reference to FIG. FIG. 19 shows a modification of the fifth embodiment and is a view showing a main part of a heat development apparatus using a heating plate and a belt.

  In the heat development apparatus shown in FIG. 19, the heating plate 161 arranged at the most upstream is curved convexly toward the endless belt 150, and the guide surface 161a of the heating plate 161 is curved and curved. A planar heater 161b is arranged along the guide surface 161a so as to be curved in the same manner. Further, the optical scanning unit shown in FIG. 12 is arranged on the upstream side of the heating plate 131.

  The endless belt 150 is disposed along the guide surfaces 161a, 132a, and 133a. The endless belt 150 is stretched over a plurality of pulleys 151 to 153, and moves endlessly in the direction A, for example, when the pulley 151 is rotationally driven. . The endless belt 150 is close to the guide surfaces 161a, 132a, and 133a between the pulleys 151 and 152, and moves in the direction A to sandwich the film F between the guide surfaces 161a, 132a, and 133a. In the state, it is transported in the transport direction H.

  19, the photothermographic film F having a latent image formed thereon is conveyed in the conveyance direction B of FIG. 18, and is interposed between the curved guide surface 161a of the heating plate 161 and the endless belt 150. When fed, the endless belt 150 moving in the direction A is sequentially conveyed from the guide surface 161a to the guide surfaces 132a and 133a, but the endless belt 150 is more tensioned and tensioned on the curved guide surface 161a. Therefore, when the film F is pressed against the guide surface 161a, the film F is brought into close contact with the heated guide surface 161a and heated.

  Accordingly, in the first step S01 of FIG. 1, the film F and the guide surface 161a can be brought into closer contact with each other, and the amount of heat transferred from the guide surface 161a to the film F can be maintained almost constant. Generation can be effectively suppressed.

  Further, since the film F is in close contact with the guide surface 161a by the curved heating plate 161 on the upstream side, the film F is in close contact with the entire width of the film F, and the density is hardly lowered. In addition, in the second step S02 that has little influence on the occurrence of density unevenness, there is no need for particularly close contact between the film F and the guide surface 133a, so that the flat heating plates 132 and 133 may be used on the downstream side. is there.

  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, in this example, an organic solvent solvent was used for film production, but an aqueous solvent can also be used. A film for heat development using an aqueous solvent can be prepared as follows.

  That is, the organic silver salt-containing layer is applied to a PET film using a coating solution in which 30% by mass or more of the solvent is water and dried to produce a photothermographic film having a thickness of 200 μm. The binder of the organic silver salt-containing layer is made of a latex of a polymer that is soluble or dispersible in an aqueous solvent (aqueous solvent) and has an equilibrium water content of 2% by mass or less at 25 ° C. and 60% RH. The aqueous solvent in which the polymer is soluble or dispersible is a mixture of water or water with 70% by mass or less of a water-miscible organic solvent. Examples of the water-miscible organic solvent include alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol, cellosolvs such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, ethyl acetate and dimethylformamide.

  Specifically, the emulsion layer (photosensitive layer) coating solution is prepared as follows. 1,000 g of fatty acid silver dispersion, 276 ml of water, pigment-1 dispersion, organic polyhalogen compound-1 dispersion, organic polyhalogen compound-2 dispersion, phthalazine compound-1 solution, SBR latex (Tg: 17 ° C.) solution, reduction Agent-1 dispersion, reducing agent-2 dispersion, hydrogen bonding compound-1 dispersion, development accelerator-1 dispersion, development accelerator-2 dispersion, color tone modifier-1 dispersion, mercapto compound-1 An aqueous solution and a mercapto compound-2 aqueous solution are sequentially added, and a silver halide mixed emulsion is added immediately before coating, and the mixed emulsion layer coating solution is fed to the coating die as it is and coated.

  According to the heat development apparatus and the heat development method of the present invention, it is possible to speed up the heat development process and reduce the size and cost while maintaining the image quality equivalent to that of a conventional large machine.

Claims (12)

A heat development apparatus for conveying a sheet film coated with a photothermographic material on one side of a support substrate while heating, and visualizing a latent image formed on the sheet film,
A heating unit for heating the sheet film, and the upstream portion of the heating unit is configured such that the heat transfer contact with the sheet film is denser than the downstream portion; A heat development apparatus characterized by comprising: 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 support substrate while heating.
A temperature raising part for raising the temperature of the sheet film to a heat development temperature;
A heat retaining part for retaining the sheet film heated to the heat development temperature,
A heat development apparatus using different heating methods for the temperature raising section and the heat retaining section. The temperature raising unit heats the sheet film while pressing the sheet film against a plate heater with a counter roller,
3. The heat developing apparatus according to claim 2, wherein the heat retaining unit heats the sheet film in a slit formed between guides having a heater at least on one side.   The concave portion is provided between the temperature raising portion and the heat retaining portion, and foreign matter from the temperature raising portion is configured to enter the concave portion. Heat development equipment.   Each of the temperature raising part and the heat retaining part has a heating body that is brought into contact with the sheet film by using an urging means, and in the temperature raising part, the heating body and the photosensitive heat developing material as compared with the heat retaining part. 3. The thermal development apparatus according to claim 2, wherein the thermal development apparatus is configured to be in close contact with each other.   The biasing means is composed of a plurality of counter rollers arranged to face the heating body, and an upstream counter roller among the plurality of counter rollers is strongly biased by the heating body. The thermal development apparatus according to claim 5.   The urging means is composed of a plurality of opposed rollers arranged to face the heating body, and the upstream facing rollers of the plurality of opposed rollers are more densely arranged in the conveying direction of the sheet film of the heating body. The thermal development apparatus according to claim 5 or 6, wherein the thermal development apparatus is arranged.   The urging means is composed of a plurality of opposed rollers arranged to face the heating body, and a gap between the upstream facing roller and the heating body among the plurality of opposed rollers becomes narrower. The heat developing apparatus according to claim 5, wherein the heat developing apparatus is any one of claims 5 to 7. A heat development method for conveying a sheet film coated with a photothermographic material on one side of a supporting substrate while heating, and visualizing a latent image formed on the sheet film,
A heating step for heating the sheet film by a heating unit, and the upstream portion of the heating unit is more closely contacted with the sheet film than the downstream portion. A heat development method comprising: A heat development method for visualizing a latent image formed on the sheet film by conveying while heating a sheet film coated with a photothermographic material on one side of a support substrate,
A temperature raising step for raising the temperature of the sheet film to a heat development temperature;
A heat retaining step for retaining the sheet film heated to the heat development temperature,
A heat developing method, wherein different heating methods are used in the temperature raising step and the heat retaining step. In the temperature raising step, the sheet film is heated while being pressed against and contacted with a plate heater by a counter roller,
11. The thermal development method according to claim 10, wherein in the heat retaining step, the sheet film is heated in a slit formed between guides having at least one heater. Each of the temperature raising step and the heat retaining step is to heat the sheet film by bringing a heating body into contact with the sheet film using an urging means,
11. The thermal development method according to claim 10, wherein in the temperature raising step, the heating body and the sheet film are brought into close contact with each other as compared with the heat retaining step.