JP2005195990A - Heat developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat developing device capable of reducing a temperature distribution in the direction of feeding a film without having to control relative positions of a heating drum and the film even when there occurs a change in a cycle time according to user's use conditions. <P>SOLUTION: The heat developing device 100 comprises a heating drum 14 which has a heat source inside and heats a heat developable photosensitive film sheet while conveying the film sheet on its outer perimeter at a first speed, a heat developing part 130 having an opposing roller 16 that presses the film sheet to the heating drum, and conveys the film sheet while holding the film sheet in concert with the heating drum over the prescribed area of the heating drum, and a heat storage roller 17 that is so disposed as to face the heating drum in the area where the film does not travel, and is capable of conducting the transfer of heat with the heating drum. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat developing apparatus that heats and develops a film sheet made of a photothermographic material while conveying it.

  In a dry laser imager that employs a film heating method using a heating drum, when the ratio between the rotation period of the heating drum and the insertion interval of the film into the heating drum is defined as the synchronization rate, when the synchronization rate is close to 1, the heating drum When the film and the film are repeatedly in contact with substantially the same region in the film conveyance direction on the outer peripheral surface of the heating drum, the temperature distribution in the circumferential direction (film conveyance direction) of the heating drum may deteriorate. It is known (for example, refer to Patent Document 1 below). In order to avoid such deterioration of the temperature distribution, it is known to reduce the temperature distribution in the circumferential direction of the heating drum by shifting the synchronization rate by design (shifting the relative position between the heating drum and the film).

  However, the rotation speed of the heating drum is closely related to the apparatus size, the development time, and the cooling capacity, and therefore it is difficult to arbitrarily determine the rotation speed. On the other hand, since the film insertion interval is determined by the cycle time of the entire apparatus, it has a relationship with the exposure / control / conveyance mechanism, and it is difficult to arbitrarily determine it.

Furthermore, even if it is difficult to shift the synchronization rate as a machine, under the user's usage conditions, the cycle time changes depending on the connected device, the number of connections, and the shooting interval, resulting in the circumferential direction of the heating drum. Temperature distribution may increase.
Japanese Patent Laid-Open No. 11-102059

  In view of the above-described problems of the conventional technology, the present invention reduces the temperature distribution in the film conveyance direction even if the cycle time changes depending on the use conditions of the user without controlling the relative position between the heating drum and the film. It is an object of the present invention to provide a heat developing apparatus that can perform such a process.

  In order to achieve the above object, a heat development apparatus according to the present invention includes a developing unit that has a heat source therein and heats a film sheet made of a photothermographic material while being conveyed at a first speed by an outer peripheral surface; A developing unit that includes at least a developing auxiliary unit that presses the film sheet against the developing unit and cooperates with the developing unit over a predetermined area of the developing unit to sandwich and convey the film sheet; and the developing unit And a heat storage means provided so as to be opposed to the developing means at the film non-passing position, and capable of transferring heat to and from the developing means.

  According to this heat development apparatus, heat can be transferred between the heat storage means and the developing means at a non-passing position of the developing means through which the film does not pass, so heat is absorbed from the high temperature side of the developing means and heat is dissipated to the low temperature side. To do. For this reason, even if the relative position between the developing unit and the film sheet is not particularly controlled and the cycle time changes depending on the use conditions of the user, the temperature distribution in the film conveying direction in the developing unit can be reduced.

  In the thermal development apparatus, a latent image is formed on the film sheet, and the film sheet on which the latent image is formed at a second speed is guided to the thermal development unit, and heated by the development unit. It is preferable to include a second transport unit that discharges the formed film, and a control unit that controls the heat developing unit, the first transport unit, and the second transport unit. In this case, it is not necessary to control, for example, the first speed of the developing means and the second speed of the first conveying means so as to shift the relative position of the film with respect to the outer peripheral surface of the developing means. Can be simplified and the burden of device design can be reduced.

  Moreover, it is preferable that the heat developing apparatus can carry and process sheet films of different sizes.

  Further, it is preferable that the developing unit is configured by a cylindrical drum, and the heat storage unit is configured by a heat storage roller that can rotate following the cylindrical drum. In this case, it is preferable that the development assisting unit is composed of a plurality of counter rollers, and a heat storage roller capable of rotating is disposed outside the region where the plurality of counter rollers are arranged.

  The heat storage roller is preferably made of a material having high thermal conductivity, for example, a metal material such as aluminum. The heat storage roller is preferably a solid roller. Moreover, a hollow roller may be sufficient if the required heat storage effect is acquired.

  The heat storage roller preferably includes a plurality of rollers. In addition, it is preferable to arrange | position a thermal storage roller so that it may extend in the direction (film width direction) orthogonal to a film conveyance direction. Thereby, the temperature distribution in the film width direction in the developing means can also be improved.

  According to the heat development apparatus of the present invention, it is possible to reduce the temperature distribution in the film transport direction without controlling the relative position of the film with respect to the outer peripheral surface of the developing means, even if the cycle time changes depending on the use conditions of the user. it can.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a main part of the thermal development apparatus according to this embodiment. FIG. 2 is a main part front view showing a modification of the heat storage roller arranged around the heating drum of FIG. FIG. 3 is a block diagram showing a control system of the heat development apparatus of FIG.

  As shown in FIG. 1, the heat developing apparatus 100 is loaded with a package in which a predetermined number of heat developable photosensitive films (hereinafter also referred to as “films”) that are sheet-like silver salt photosensitive materials are packaged. A supply unit 110 having first and second loading units 11 and 12 and a conveyance unit 5 that conveys the film one by one for exposure and development; and a film fed from the supply unit 110 is exposed to expose a latent image Cooling unit including an exposure unit 120 for forming the image, a heat developing unit 130 for thermally developing the film on which the latent image is formed, a densitometer 200 for measuring the density of the developed film and obtaining density information, a conveying roller 144, and the like. Unit 150.

  The first and second loading units 11 and 12 of the supply unit 110 can be loaded with a plurality of films having different sizes, respectively, and the first loading unit 11 or the second loading unit 12 can transfer 1 film. Each sheet is conveyed in the arrow direction (1) in FIG. 1 by the conveyance unit 5 and the conveyance roller pair 139, 141. Switching of film conveyance between the first and second loading units 11 and 12 can be performed by controlling each conveyance unit 5.

  Then, the film is conveyed in the arrow direction (2) and a latent image is formed by the exposure unit 120. Next, the film is conveyed in the arrow direction (3) by the pair of conveyance rollers 142 and 143, and the latent image is visible in the heat developing unit 130. It is imaged, further conveyed in the arrow direction (4), cooled by the cooling conveyance unit 150, and then discharged to the stacking unit 160. In this way, the film F is stacked on the stacking unit 160 as shown in FIG.

  The exposure unit 120 forms an image of a laser beam L, which has been intensity-modulated based on an image signal input from the outside, on a film by an fθ lens or the like, and deflects it by a rotary polygon mirror (polygon mirror) to perform main scanning on the film F. At the same time, the film F is sub-scanned by moving it relative to the laser beam L in the direction substantially perpendicular to the main scanning direction by the conveying roller pair 142, and a latent image is formed on the film F using the laser beam L.

  When the exposure unit 120 irradiates the film F, which is a photothermographic material, with exposure, the silver halide grains are exposed to the area irradiated with the laser light L to form a latent image. Thus, a latent image based on the image signal is formed on the film F.

  The thermal development unit 130 includes a heating drum 14 as a heating member that can be heated while holding the film F in close contact with the outer periphery. The heating drum 14 has a heat generating heater 14a (FIG. 2) attached to the inner peripheral surface thereof, and heats the outer peripheral surface by energizing the heat generating heater, so that the film F that has adhered is brought into a predetermined minimum heat development temperature. As described above, the latent image formed as described above is formed on the film F as a visible image by maintaining a predetermined heat development time. Here, the minimum heat development temperature is a minimum temperature at which the latent image formed on the film F starts to be thermally developed, and is, for example, 95 ° C. or higher. On the other hand, the heat development time refers to a time that should be maintained at a temperature equal to or higher than the minimum heat development temperature in order to develop the latent image on the film F to a desired development characteristic.

  The film F contains photosensitive silver halide grains, an organic silver salt, and a silver ion reducing agent, and is not substantially thermally developed at a temperature of 40 ° C. or lower. For example, the film F is heated at a temperature of 95 ° C. or higher. Developed.

  1 has an exhaust fan for exhausting the gas generated from the film heated by the heat developing unit 130 to the outside above the heating drum 14 of the heat developing unit 130 and on the back side of the apparatus. Is provided. As shown in FIG. 1, a deodorizing filter 170 is disposed between the heat developing unit 130 and the exhaust fan for deodorizing gas components generated during film heating.

  As shown in FIG. 1, on the outside of the heating drum 14, a plurality of rotatable counter rollers 16 having a smaller diameter than the heating drum 14 as guide members and pressing members are provided as developing auxiliary means. The drum 14 is disposed so as to face the outer circumferential surface of the heating drum 14 in the width direction (perpendicular to the paper surface of FIG. 1). When the film F enters between the outer periphery of the heating drum 14 and the opposing roller 16, the film F is pressed against the outer peripheral surface of the heating drum 14 with a predetermined force, and is conveyed along with the rotation of the heating drum 14. In the meantime, the entire surface is uniformly heated by the heating drum 14.

  As described above, a plurality of small-diameter counter rollers 16 are opposed to the outer peripheral surface of the heating drum 14, and a conveyance path is formed between the plurality of counter rollers 16 and the heating drum 14 in the circumferential direction of the heating drum 14. Is done. In this conveyance path, the film is conveyed while being heated by the rotation of the heating drum 14 in the rotation direction R so as to be wound around the heating drum 14. In this case, since the winding angle of the film around the heating drum 14 is generally about 180 to 270 °, there is a portion that does not become the film transport path of about 90 to 180 °. At this film non-passing position, a plurality of heat storage rollers 17 capable of rotating as heat storage means are arranged in contact with the heating drum 14 so as to extend in the width direction of the heating drum 14 (direction perpendicular to the circumferential direction). ing.

  The heat storage roller 17 is preferably made of a material having high thermal conductivity such as a metal material, and is made of, for example, solid cylindrical aluminum or steel. The heat storage roller 17 is brought into contact with the heating drum 14 so as to rotate as the heating drum 14 rotates. The heat storage roller 17 may be a hollow roller as long as the necessary heat storage effect can be obtained. In the case of the hollow roller, the same roller as the opposing roller 16 can be used, so a special part is prepared. This is advantageous in terms of component costs.

  By using the heat storage roller 17 as a thermal buffer (thermal condenser), the temperature distribution in the circumferential direction of the heating drum 14 is relaxed, and further, the temperature distribution in the width direction of the heating drum 14 is also improved. Get the effect.

  FIG. 2 shows a modified example of the heat storage roller arranged around the heating drum of FIG. 1, but the same heat storage at a position away from the heat storage roller 17 within the film non-passing range B of the heating drum 14 as shown in FIG. 2. A plurality of rollers 18 are arranged in contact with the heating drum 14. As a result, the effect of relaxing the temperature distribution in the circumferential direction of the heating drum 14 and the effect of improving the temperature distribution in the width direction of the heating drum 14 can be further obtained.

  Next, a control system of the heat development apparatus of FIG. 1 will be described with reference to FIG. A control unit 152 including a central processing unit (CPU) or the like controls the developing temperature of the heating drum 14 by controlling the energization amount to the heat generating heater 14 a on the inner peripheral surface of the heating drum 14, and the heat developing unit 130. A motor 142a for rotating and driving the upstream conveying roller pair 142, 143 is controlled to control the film conveying speed (second speed) to the heating drum 14, and a motor 14b for rotating the heating drum 14 is further controlled. The film conveyance speed (first speed) on the outer peripheral surface of the heating drum 14 is controlled. Further, the motor 144a that rotationally drives the conveyance roller 144 on the cooling side (the discharge side of the heating drum 14) of the cooling conveyance unit 150 is controlled to control the film discharge / conveyance speed.

  As shown in FIGS. 1 and 2, the heat storage rollers 17 and 18 arranged in the film non-passing range B (FIG. 2) around the heating drum 14 are in contact with the rotating heating drum 14 and rotate to rotate. When the 14 side is high temperature, heat is absorbed from the heating drum 14 side, and when it is low temperature, heat is radiated to the heating drum 14 side, so the temperature distribution in the circumferential direction (film transport direction) of the heating drum 14 can be relaxed. Further, since the heat storage rollers 17 and 18 extend in the width direction of the heating drum 14 (the direction perpendicular to the paper surface in FIGS. 1 and 2), the temperature distribution in the width direction can be improved.

  Since the temperature distribution in the circumferential direction of the heating drum 14 can be relaxed as described above, special control for shifting the relative position of the film with respect to the outer peripheral surface of the heating drum 14 is not necessary. For example, the film conveyance speed (first speed) of the heating drum and the film conveyance speed (second speed) by the upstream conveyance roller pairs 142 and 143 are controlled to control the rotation period of the heating drum 14 and the film heating drum 14. Since it is not necessary to control the synchronization rate with the entry interval, the configuration of the control unit 152 is simplified, and the burden of device design can be reduced.

  Therefore, since the speed of the heating drum 14 and the film entry interval can be determined without being aware of the synchronization rate as in the prior art, the degree of freedom of design is increased, and a device that is connected under the use conditions of the user, Even if the cycle time changes depending on the number of connections and the shooting interval, it is irrelevant to such changes in use conditions, and a stable image can always be output.

  As an embodiment, as shown in FIG. 2, a plurality of heat storage rollers 17 and 18 are arranged in a film non-passing range B around the heating drum 14, and the heating drum that is heating and transporting the film at the position of a predetermined opposing roller 16 is used. The temperature of 14 outer peripheral surfaces was measured in the width direction center part. As a comparative example, the temperature was measured in the same manner as in the example except that there was no heat storage roller. The results of Examples and Comparative Examples are shown in FIG. Furthermore, the result of the Example which measured the temperature of the outer peripheral surface of the heating drum 14 in the width direction, and the comparative example without a heat storage roller is shown in FIG.

The main data of the example is as follows.
Heating drum: 140 mm in diameter (silicon tube is coated on an aluminum tube, and fluororesin is coated on it)
Opposing roller: Diameter 10mm (Material: Steel material)
Heat storage roller: 10mm in diameter (Material: Steel material)
Development temperature: 123 ° C
Processing speed: 120 sheets / hour

  FIG. 4A is a diagram showing the measurement result of the comparative example in which the heat storage roller is not arranged in relation to the elapsed time and the relative temperature, and FIG. 4B is the measurement result of the example in which the heat storage rollers 17 and 18 are arranged. Is a diagram showing the relationship between elapsed time and relative temperature. From the results of the examples, it can be seen that the relative temperature fluctuation range in the circumferential direction (the center in the width direction) is smaller and the overall temperature fluctuation is smaller than in the comparative example without the heat storage roller. The temperature distribution in the circumferential direction could be relaxed.

  FIG. 5 is a diagram showing the relationship between the position in the width direction and the measured temperature of the outer peripheral surface of the heating drum in the examples and comparative examples. In FIG. 5, the curve b at the time of processing the small size film in the example shows the change in the upper limit temperature, the curve b ′ shows the change in the lower limit temperature, and the curve a at the time of processing the small size film in the comparative example is the upper limit temperature. Similarly, the curve a ′ shows the change in the lower limit temperature.

  In the example, it was found from FIG. 5 that the upper limit temperature and the lower limit temperature were closer to the set temperature than the comparative example within the range of the conveyance width of the small film, and the temperature distribution in the width direction of the heating drum 14 could be improved. . In the non-passing part of the small-size film, the curves a and a ′ in the comparative example have a temperature outside the allowable temperature range (122.4 to 123.8 ° C.), whereas the curve b and in the example. Since the portion of the temperature b ′ is slightly outside the allowable temperature range, when processing a large size film that also passes through the non-passing portion of FIG. 5 after processing the small size film of FIG. Can be restored.

  As described above, the best modes and examples for carrying out the present invention have 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. is there. For example, in FIGS. 1 and 2, only a plurality of heat storage rollers 18 (the heat storage roller 17 may be omitted) may be used due to the space of the heat developing unit 130, and one heat storage roller 17 and one heat storage roller 18. It is good also as one, and you may arrange | position another heat storage roller in the position different from the heat storage rollers 17 and 18. FIG.

It is a front view which shows the principal part of the heat development apparatus by this Embodiment. It is a principal part front view which shows the modification of the thermal storage roller arrange | positioned around the heating drum of FIG. FIG. 2 is a block diagram showing a control system of the heat development apparatus of FIG. 1. FIG. 4A is a diagram showing the measurement result of the comparative example in which the heat storage roller is not arranged in relation to the elapsed time and the relative temperature, and FIG. 4B is the measurement result of the example in which the heat storage rollers 17 and 18 are arranged. Is a diagram showing the relationship between elapsed time and relative temperature. It is a figure which shows the relationship between the width direction position and measured temperature of the outer peripheral surface of a heating drum in an Example (curves b and b ') and a comparative example (curves a and a').

Explanation of symbols

14 Heating drum (developing means)
16 Opposing roller (development assisting means)
17, 18 Heat storage roller (heat storage means)
DESCRIPTION OF SYMBOLS 100 Thermal development apparatus 110 Supply part 120 Exposure part 130 Thermal development part 142,143 Pair of conveyance rollers (1st conveyance means)
144 Conveying roller (second conveying means)
150 Cooling and transporting part 152 Control part B Film non-passing range F Film (film sheet)
R Heating drum rotation direction, heating drum circumferential direction

Claims (7)

A developing unit having a heat source therein and heating a film sheet made of a photothermographic material at a first speed by an outer peripheral surface; pressing the film sheet against the developing unit; A heat developing means having at least a developing auxiliary means for nipping and transporting the film sheet in cooperation with the developing means over a region;
And a heat storage means provided so as to be opposed to the developing means at a film non-passing position of the developing means and capable of transferring heat to and from the developing means. A first conveying unit that forms a latent image on the film sheet and guides the film sheet on which the latent image is formed at a second speed to the heat developing unit;
A second conveying means for discharging the film heated by the developing means;
The thermal development apparatus according to claim 1, further comprising a control unit that controls the thermal development unit, the first conveyance unit, and the second conveyance unit. The heat developing apparatus according to claim 1, wherein sheet films having different sizes can be conveyed. 4. The heat developing apparatus according to claim 1, wherein the developing unit is formed of a cylindrical drum, and the heat storage unit is formed of a heat storage roller that can rotate following the cylindrical drum. . The heat development apparatus according to claim 4, wherein the heat storage roller is made of a material having high thermal conductivity. 6. The heat developing apparatus according to claim 4, wherein the heat storage roller is a solid roller. The heat development apparatus according to claim 4, wherein the heat storage roller includes a plurality of rollers.

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