Patent Publication Number: US-6667754-B2

Title: Heat developing apparatus

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a heat developing apparatus by which a photothermographic element is heated and developed, and particularly to a countermeasure by which the image quality of the element conveyed, is not badly affected by the condensates from gas generated at the heat developing apparatus, and further, to the collection and recovery of the condensates from gas generated at the heat developing apparatus. 
     In the heat developing apparatus by which the photothermographic element is heat-developed, an exposed photothermographic element is nipped between a drum-like heat applying member (heat drum) which is temperature controlled to a predetermined heat developing temperature, and an urging member (opposite roller) opposite to this member, and the element is heated while the heat applying member is rotated in the held status. After that, the photothermographic element is separated from the heat applying member, cooled and the heat development is stopped, and the photothermographic element is conveyed to the delivery direction. The photothermographic element is heat developed through such the process. 
     As described above, in the heat developing apparatus, in order to obtain a desired developing density, the predetermined thermal energy is given to the photothermographic element for a predetermined time. 
     On the one hand, in the photothermographic element, the photosensitive silver halide, organic acid silver salt, binder, and other various additives or solvents are contained. 
     As repeating the developing processing, when the heat applying member (heat drum) or urging member (opposite roller) and photothermographic element are in contact with each other at the high temperature condition, the material contained in the photothermographic element or the organic acid isolated from the organic acid silver salt is transferred onto the heat drum or the opposite roller, vaporized or decomposed and after that, accumulated inside the heat developing section as condensates from gas, and thereby, the image defect or density lowering occurs. Accordingly, after the processing of a predetermined amount or a predetermined period of photothermographic element, the maintenance washing of the heat developing apparatus has been necessary. 
     Further, in order to increase the nipping and conveying performance under the high temperature, the elastic body is used for the surface of the heat drum or opposite roller in many cases, and in such the case, there are problems that the composition of the elastic body is deteriorated due to the deterioration by the heat or the material generated from the film, and the strength of the elastic body itself is lowered, further, when the organic solvent type cleaning agent is used for removing the accumulated foreign matter, the crack is generated on the elastic body itself, or the life of the elastic body itself is reduced. 
     SUMMARY OF THE INVENTION 
     The first object of the present invention is to minimize foreign matter such as the condensates from gas generated at a developing section, accumulated on a guide member particularly to guide the photothermographic element from upstream into the developing section, or to guide from the inside of the developing section to downstream. 
     The second object of the present invention is to minimize foreign matter such as the condensates from gas generated at a developing section accumulated on the surface of members inside the heat developing section and members on their periphery. 
     The first object is attained by any one of the following structures (1) to (12). 
     (1) A heat developing apparatus which is characterized in that in the heat developing apparatus having a heat applying member to conduct the heat developing by heating a photothermographic element in a developing station, and a guide member to guide the element to the developing section, or a guide member to guide the element from the developing section to the downstream portion in the developing station covered by a housing, at least either one of surfaces of the guide members is structured by a material having a low heat conductivity such as, for example, a heat insulating material. 
     (2) A heat developing apparatus according to (1), wherein an exhaust apparatus is connected to the developing section, and a suction air portion from the developing section is in the vicinity of an installation position of at least either one of the guide members. 
     (3) A heat developing apparatus according to any one of (1) or (2), wherein the guide members are exposed outside the developing section. 
     (4) A heat developing apparatus according to (3), wherein the heat conductivity of each of the guide members is not larger than 1 W/(m·K). 
     (5) A heat developing apparatus according to any one of (1) to (4), wherein the material of each of the guide members is a resin material or a rubber-like elastic body. 
     (6) A heat developing apparatus which is characterized in that: in the heat developing apparatus having a heat applying member to conduct the heat developing by heating a photothermographic element in a developing station, and a guide member to guide the element into the developing station, or a guide member to guide the element from the developing section to the downstream portion in the developing station covered by a housing, there is arranged a heat applying means for maintaining at least either the guide member to guide the element into the developing station, or the guide member to guide from the developing station to the downstream portion, at not lower than 80° C. 
     (7) A heat developing apparatus which is characterized in that: in the heat developing apparatus having a heat applying member to conduct the heat developing by heating a photothermographic element in a developing station, and a guide member to guide the element into the developing station, or a guide member to guide from the developing station to the downstream portion in the developing station covered by a housing, there is arranged a heat applying means for maintaining the difference between the heat developing temperature and the temperature of at least either the guide member to guide the element into the developing station, or the guide member to guide the element from the developing station to the downstream portion, at not higher than 50° C. 
     (8) A heat developing apparatus which is characterized in that: in the heat developing apparatus having a heat applying member to conduct the heat developing by heating a photothermographic element in a developing station, and a guide member to guide the element into the developing station, or a guide member to guide from the developing station to the downstream portion in the developing station covered by a housing, there is arranged that at least either the guide member to guide the element into the developing station, or the guide member to guide the element from the developing station to the downstream portion, does not directly face the heat applying member. 
     (9) A heat developing apparatus according to (6), wherein the shielding member is arranged so that the path of the element passing on the guide member does not directly face the heat applying member. 
     (10) A heat developing apparatus according to (9), wherein the shielding member is arranged from the leading edge portion of the guide member in the conveying direction to the downstream of the guide member in the conveying quad direction. 
     (11) A heat developing apparatus according to any one of (8), (9) or (10), wherein the shielding member serves also as the guide member. 
     (12) A heat developing apparatus which is characterized in that: in the heat developing apparatus having a heat applying member to conduct the heat developing by convection heating a photothermographic element conveyed to a developing station, and a guide member to guide the element into the developing station, or a guide member to guide the element from the inside of the developing station to the downstream portion in the developing station covered by a housing, the outside air is taken in from the vicinity of the guide member so that the gas generated from the photothermographic element does not reach at least either the guide member to guide the element into the developing station, or the guide member to guide from the inside of the developing station to the downstream portion. 
     The second object is attained by any one of the following structures (13) to (22). 
     (13) A heat developing apparatus which is characterized in that: in the heat developing apparatus having a heat applying member to conduct the heat developing by convection heating a photothermographic element in the developing station covered by a housing, an accumulation member for solidifying or precipitating a gas is arranged in the housing. 
     (14) A heat developing apparatus according to (13), wherein the accumulation member is structured by the material having the high heat conductivity. 
     (15) A heat developing apparatus according to any one of (13) or (14), wherein the accumulation member is provided with a cooling structure or cooling apparatus for cooling the accumulation member. 
     (16) A heat developing apparatus according to (15), wherein the temperature of the accumulation member is made not higher than 80° C. by the cooling structure or cooling apparatus. 
     (17) A heat developing apparatus according to (15), wherein the temperature of the accumulation is made lower than the heat developing temperature by not smaller than 40° C. by using the cooling structure or cooling apparatus. 
     (18) A heat developing apparatus according to any one of (13)-(17), wherein the accumulation member is made detachable. 
     (19) A heat developing apparatus according to any one of (13)-(18), wherein the accumulation member is disposed on the lower side of the passing path of the photothermographic element. 
     (20) A heat developing apparatus according to any one of (13)-(18), wherein the accumulation member is on the upper side of the passing path of the photothermographic element, and is provided with a liquid dripping prevention means for preventing liquid collected on the accumulation member from dripping to the element. 
     (21) A heat developing apparatus according to any one of (13)-(18), wherein the accumulation member serves also as the guide member for guiding the photothermographic element. 
     (22) A heat developing method which is characterized in that: in the heat developing method by which the photothermographic element is nipped and conveyed at a predetermined speed by a heat applying means to apply the heat to a photothermographic element, and an urging means to urge the element to the heat applying means, and the photothermographic element is developed, an accumulation means of the condensates from gas is arranged in the inside of the heat developing section having the housing covering the heat applying means and urging means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a general sectional view of a heat developing apparatus used in the present invention. 
     FIG.  2 ( a ) is a general perspective view and FIG.  2 ( b ) is a partially enlarged view of a developing section. 
     FIGS.  3 ( a ) and  3 ( b ) are sectional views of a heat drum and an opposite roller, respectively. 
     FIG. 4 is a sectional view of an example of an attachment of an exhaust apparatus to the developing section. 
     FIG. 5 is a sectional view of an example of the developing section in which a heat applying means is arranged onto a guide member. 
     FIG. 6 is a sectional view of an example of the developing section in which a single member of paired guide members is a shielding member. 
     FIG. 7 is a sectional view of a developing section in which an accumulation member (means) is arranged in a housing. 
     FIG. 8 is a sectional view of another developing section in which the accumulation member (means) is arranged in the housing. 
     FIG. 9 is a sectional view of yet another developing section in which the accumulation member (means) is arranged in the housing. 
     FIG. 10 is a sectional view of a furthermore developing section in which the accumulation member (means) is arranged in the housing. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments of the present invention will be described below. 
     FIG. 1 is a general sectional view of a representative heat developing apparatus according to an embodiment of the present invention, and FIG. 2 is a general perspective view showing a structure of a representative developing section. 
     Referring to FIGS. 1 and 2, the heat developing apparatus will be described below. A heat developing apparatus  100  has a feed section  110  to successively feed a sheet-like photothermographic element (simply called also a film) one by one sheet, an exposure section  120  to expose a fed film F, a developing section  130  to develop the exposed film, and a cooling section  150  to stop the development. The feed section  110  is provided on the upper stage and lower stage, and a film F accommodated in a case C is accommodated for every case C. The film F is taken from the case C by a suction apparatus and conveying roller of a taking apparatus  140 , and pulled out in the arrowed direction in the drawing (horizontal right direction). Further, the film F pulled from the case C is conveyed in the arrowed direction (downward) by a conveying apparatus  141  composed of roller pair. 
     The film F conveyed below the heat developing apparatus  100  is conveyed in the arrowed direction in the drawing (leftward) by the conveying apparatus  142 . It is conveyed by a conveying apparatus  143  composed of roller pair from the left side surface of the heat developing apparatus  100  to the arrowed direction (upward), and in that case, in the exposure section  120 , it is scanning-exposed by the laser light L in the infrared region (wavelength 780-860 nm), for example, by the laser light of the wavelength 810 nm. 
     When the film F receives the laser light L, a latent image is formed. After that, the film F is further conveyed in the arrowed direction (upward), and when it reaches the supply roller pair  144 , it is supplied to a heat drum  1  as it is. In this manner, in the supply to the heat drum  1 , there is also a system in which the supply is conducted at a random timing when the film F reaches the roller, further, when it reaches the roller, the film F is stopped once, and it may be supplied at a predetermined timing. In the latter case, it becomes a system in which the supply roller pair  144  has a function to decide a timing to supply the film F to the heat drum  1  of the developing section  130  rotating at a predetermined rotating speed, and in the case where the drum  1  is rotated to the next supplied position on the one round of the heat drum, when the supply roller pair  144  starts the rotation, the film F is supplied to a predetermined position on the outer periphery of the heat drum  1 . 
     Further, while the heat drum  1  holds the film F on its outer periphery, it rotates in the arrowed direction. In such the condition, the heat drum  1  heats and heat-develops the film F, and forms the visual image from the latent image. 
     After that, when the heat drum in FIG. 1 is rotated to its rightward, the film F is separated from the heat drum  1 , and conveyed in the arrowed direction and after cooled and conveyed by a plurality of conveying roller pair  145  of the cooling section  150 , the film F is delivered to the delivery tray  160  so that it can be taken from the upper portion of the heat developing apparatus  100 . 
     FIG.  2 ( a ) is a general perspective view showing the inside structure of the developing section  130 , and FIG.  2 ( b ) is a partially enlarged view of X of FIG.  2 ( a ). 
     The developing section  130  has a heat drum  1  as a heat applying member (which is also a heat applying means) to heat the film F while holding it almost in close contacting with the outer periphery. The heat drum  1  has a function to form the formed latent image as a visual image on the film F by maintaining the film F for a predetermined time at higher than the predetermined lowest heat developing temperature. Herein, the lowest heat developing temperature means the lowest temperature at which the latent image formed on the film F is started to be heat developed, and in the film of the present embodiment, it is more than 100° C. On the one hand, the heat developing time means the time to maintain at higher than the lowest heat developing temperature in order to develop the latent image of the film F into the desired image characteristic. In this connection, a film formed in such a manner that the film F is not practically heat developed at not more than 40° C., is preferable. 
     On the outside of the heat drum  1 ,  20  and several rollers of small diameter opposite rollers  2  as the urging member (which is also a urging means) are provided, and they are opposite in parallel to the heat drum  1  and arranged in the peripheral direction of the drum  1  at equal intervals. At both ends of the heat drum  1 , guide brackets  4  supported by the frame  20  are provided on both sides. 
     On each of guide brackets  4 , a long hole  5  extending in the radial direction is formed. From this long hole  5 , shafts  21  provided at both end portions of the opposite roller  2  are protruded. To the shaft  21 , one end of a coil spring  22  is respectively attached, and the other end of the coil spring  22  is attached to the vicinity of the inside edge of the guide bracket  4 . Accordingly, each of opposite rollers  2  is urged to the outer periphery of the heat drum  1  by a predetermined force based on the urging force of the coil spring  22 . The film F, when it enters between the outer periphery of the heat drum  1  and the opposite rollers  2 , is pressed onto the outer peripheral surface of the heat drum  1  with a predetermined force, thereby, the film F can be uniformly heated all over the surface. 
     The shaft  11  coaxially connected with the heat drum  1 , extends outside of the end portion of the frame  20 , and by the shaft bearing  40 , it is rotatbly supported by the frame  20 . On a rotation axis  23  of a micro step motor (not shown) which is arranged below the shaft  11 , and attached onto the frame  20 , a gear (not shown) is formed. On the one hand, a gear is formed also on the shaft  11 . Trough a timing belt (belt on which a gear is provided)  25  which connects both gears, the motive power of the micro step motor is transmitted to the shaft  11 , thereby, the heat drum  1  is rotated. In this connection, the transmission of the motive power from the rotation axis  23  to the shaft  11 , may be conducted not through the timing belt, but through a chain or a gear train. 
     FIGS.  3 ( a ) and  3 ( b ) show sectional views when the surface of the heat drum and opposite roller is coated by the elastic body. FIG.  3 ( a ) is a sectional view of the heat drum  1 , and onto the heat drum, an aluminum made support tube  36  which is a metallic support member, and on the inner periphery of the tube, a plate-like heater  32  is attached over the all periphery, and under the control of a control-use electronic apparatus, not shown, it is heated. On the outside of the support tube  36 , a flexible elastic body  38  is provided. The elastic body may be indirectly attached onto the support tube  36 . 
     Because the elastic body  38  is used, the film F is in more surely close contact with the heat drum  1  by the opposite roller  2  shown in FIG.  3 ( b ). It is preferable that the hardness of the elastic body  38  is not higher than 70 (specially, not higher than 60) in the Shore hardness measured by the durometer. 
     As a material to form the elastic body, for example, when it is silicon rubber, poly urethane rubber, natural rubber, or a material having the elasticity and heat resistance, it is not specifically limited. 
     It is preferable that the thickness of the elastic body  38  is within the range from 0.1 mm to 2 mm, and more preferably it is not smaller than 0.4 mm. Further, it is preferable that the fluctuation of the thickness of the elastic body  38  is not larger than 20% (specially, not larger than 10%) on the surface area. 
     The heater  32  is attached onto the inner periphery of the heat drum, and for example, a foil heater which is etched and resistive, can be used. 
     The heater control-use electronic apparatus, not shown, can adjust the electric power supplied to the heater  32  corresponding to the temperature information sensed by the temperature detecting means, not shown, arranged in the heat drum  1 . When the heater control-use electronic apparatus controls the heater  32 , the outer surface temperature adjustment of the heat drum  1  is conducted so that it becomes the temperature appropriate for the development of the specific film F. 
     In the present embodiment, as the urging member, the rotatable opposite roller  2  is used. However, the other means such as a small movable belt can also be used. In the present embodiment, it is preferable that, as the opposite roller  2 , an aluminum tube whose outer diameter is 1-2 cm, and whose wall thickness is 2 mm, is used. 
     This opposite roller may also be formed of a solid metallic tube, however, its surface may also be coated by the elastic body used for the surface of the heat drum, and in FIG.  3 ( b ), a sectional view showing a structure of the opposite roller having the elastic body on its surface is shown. On the surface of the aluminum tube, the elastic body is coated. 
     When the surface of the opposite roller is coated by the elastic body, the surface of the heat drum may have the above-described elastic body, and further, the surface of the heat drum may also be coated by a harder elastic body. 
     As described above, in the photothermographic element (film F), the developer, organic acid silver salt, binder, and other various additives or solvents are included, and while development is conducted by the heat developing apparatus, it is exposed in the high temperature of 100° C. to 160° C., and the chemical reaction of the development is conducted. While that time, the heat decomposition due to the exposition of the high temperature, or various phenomena such as gasification, sublimation, peeling, or transferring, occur. A gas which is generated at this time is called a gas body, and the gas body in which it is solidified or precipitated, is called condensates from gas. 
     Then, after the heat developing processing is conducted for a long period of time, when the heat developing apparatus is disassembled, there can be seen a phenomenon that the elastic body of the heat drum surface or the elastic body of the surface of the opposite roller is discolored, and a foreign matter is accumulated on a portion at which it is seemed that the temperature is low. 
     Specially, in the consideration of the present inventors, when the condensates from gas generated at the development is adhered to the guide member to guide the photothermographic element to the developing section  130 , or the conveying surface of the element of the guide member to guide from the developing section inside to the downstream portion, finally, they adhere to the element and the image quality lowering occurs. Accordingly, even when, as the whole of the inside of the housing, so large condensates adherence is not caused, it is a big problem. 
     In the above description, in the gas body generated in the development, because it is condensed and adhered when it contacts with a member whose temperature is lower than the heat developing temperature, to the guide member arranged in the vicinity of the heat applying member, coupled with the high gas body density in this vicinity, the condensates from gas easily adheres, and specially, at the temperature not higher than 80° C. which is a melting point of the organic acid, the condensates adherence is large. 
     Accordingly, to the guide member to guide to the developing section, or the guide member to guide from the developing section inside to the downstream portion, a countermeasure by which the condensates adherence does not occur, is necessary. 
     Then, after the heat developing processing is conducted for a long period of time, when the heat developing apparatus is disassembled, the condensates from gas adheres and accumulates onto the member inside the heat developing section or a member in its periphery. Or, a phenomenon that the elastic body on its surface is discolored, is seen. 
     Ordinary, although these maintenance and washing are different depending on the processed amount or using frequency, according to the present invention, because the condensates from gas accumulated inside the heat developing section can be collected and recovered in the shape which is effective and any problem does not occur, and the deterioration of the using elastic body can also be effectively prevented, the good image characteristic can be maintained over a longer period of time. 
     Next, referring to the drawings appropriately, the embodiment of the present invention will be described. 
     Initially, even when the developing processing is completed and the temperature of the developing section is lowered, it is necessary that the material having the low heat conductivity, for example, a heat insulating material is used for the guide member so that the temperature of the guide member is not rapidly lowered, and for the material for the guide member, it is preferable that the heat conductivity is lower than 1 W/m·K. As the material which has the low heat conductivity, and which is easy in the processing molding, and which is considerably low cost, there are various kinds of resins. Specifically, poly imide type resin, poly ester type resin, poly carbonate type resin, or poly amide type resin can be listed. Further, as the material which has a slight elasticity, each kind of rubber, for example, silicon rubber, or urethane rubber, can be listed. 
     Further, it is necessary that the density of the gas body in the developing section is made low as possible. In FIG. 4, an example in which an exhaust apparatus  8  is attached onto the developing section  130  for that purpose, is shown in a cross section. As shown in the drawing, it is preferable that a suction port  803  from the developing section is provided in the vicinity of the guide member (in FIG. 4, it is provided in the vicinity of the guide member  809  guiding the film from the inside of the development section to the downstream portion). Alternatively, as another countermeasure to make the density of the gas body inside the developing section low as possible, it is also an effective countermeasure that an intake  802  of the outside air is provided in the vicinity of the guide plate (in FIG. 4, it is provided in the vicinity of the guide member  808  to guide the film into the developing section). Herein, numeral  801  is a filter, and numeral  805  is an exhaust port to the outside. 
     In this connection, the vicinity means the nearness at which the gas body density of the contact surface with the guide member, specially, with the photothermographic element can be effectively lowered. 
     Further, as shown in FIG. 5, it is also effective that, onto the guide member  808  to guide to the developing section  130 , or the guide member  809  to guide from the inside of the developing section to the downstream portion, the heat applying means  810  is provided and the guide members are maintained at higher than 80° C., or the temperature difference from the heat developing temperature is maintained at lower than 50° C. 
     Further, there is also a countermeasure by which, in order to make the condensates adherence hardly occur on the contact surface of the photothermographic element with the guide member  808  to guide to the developing section  130 , or the guide member  809  to guide from the inside of the developing section to the downstream portion, this surface is made not to directly face to the heat applying member  1 , and thereby, the gas body density to reach the contact surface is lowered. Therefore, it is effective that the shielding member of the gas body is arranged. 
     As the actual embodiment, it is clear that the shielding member of the gas body may be combined with the member having another function. 
     In FIG. 6, there are guide members  808 ′ and  809 ′ which are paired with the guide members  808  and  809 , and an example in which they are combined with a shielding member of the gas body, is shown in the sectional view. 
     According to the present invention, a method by which a foreign matter such as the condensates from gas is not accumulated onto the guide member to guide the photothermographic element into the developing section, or onto the guide member to guide from the inside of the developing section to the downstream portion, can be provided, and the heat developing apparatus by which the guide member is maintained clean, and a fine image can be obtained for a long period of time, can be provided. 
     FIG. 7 shows the developing section  130  of the heat developing apparatus according to the present invention, and in its housing  131 , a heat drum (heat applying member)  1  and an opposite roller (urging member)  2  is housed. 
     Then, numeral  132  is an accumulation member (means) of the condensates from gas. As described above, the organic acid separated from the material included in the photothermographic element, or the organic acid silver salt, is transferred onto the heat drum or opposite roller, or after being gasified or decomposed, is accumulated in the inside of the heat developing section as the condensates from gas, and it is a member (means) onto which this condensates from gas is effectively adhered. 
     As the material of the accumulation member, it is not specially limited, but characteristically, because it is preferable that the material has good heat conductivity and is easily cooled, from this meaning, the metals is preferable. Further, it is also naturally considered that, after the condensates from gas is collected, the present member (means) is taken out and replaced with new member, therefore, it is preferable that it is detachably attached onto the developing section  130 . The metals are preferable materials also from the meaning that the processing molding is comparatively easy, and a low cost material can also be selected, and the detachable integrated member can be easily made. 
     Further, when the condensates from gas is collected, it is preferable that the accumulation member is held at a considerably lower temperature than at least the heat developing temperature in order to easily be condensed. Therefore, it is preferable that the accumulation member has a cooling structure or cooling apparatus. The cooling structure means a structure in which, for example, as shown in FIG. 8, an accumulation member  132  is made of metal having high heat conductivity, and its one end extends to a cooling section  150  and is a cooling temperature section  133 , and consequently, the whole of the accumulation member is cooled. Further, the cooling apparatus may also be provided with an exclusive heat exchanger for the accumulation member, and an intake apparatus of the cooling air for cooling the accumulation member may be provided, and for example, an apparatus for hitting the outside air onto the back surface of the accumulation member may be provided. Of course, also in this case, as described above, the cooling air of the cooling section  150  may be utilized. 
     In any case, it is preferable that, according to the cooling structure or cooling apparatus, the accumulation member, specially, the surface to collect the condensates from gas is at lower than 80° C. Or, it is preferable that the temperature is made lower by the temperature more than 40° C. from the heat developing temperature. In this connection, when the temperature is lowered, it is preferable for the accumulation of the condensates, however, when it is too lowered, there is also a possibility that the bad influence is generated in the developing processing. As a criterion of the lower limit value, it is preferable that it is more than 30° C., or the difference from the heat developing temperature is lower than 90° C. 
     Further, relating to the arrangement position of the accumulation member in the housing  131  of the developing section  130 , specially, there is no limitation. When the accumulation member is taken out, from the point that the condensates from gas drops off, and does not stain the photothermographic element, heat applying member or urging member, for example, as shown in FIGS. 7 and 8, it is preferable that the accumulation member is arranged on the lower side, that is, in the lower portion of the housing  131 . 
     However, from the point that the condensates from gas is effectively collected, because the gas body exhausted from the photothermographic element has an inclination to stay in the upper portion of the housing  131 , it can also be said it is preferable that it is arranged in its upper portion. However, when it is arranged in the upper portion, it is necessary to provide the shape that the substance in which the gas body is collected by the accumulation member, and condensed into the liquid, does not drop on the photothermographic element, and there is case in which it is also necessary that the substance is made to drop out of the passing path, or a liquid reservoir is provided in the lower portion of the accumulation member. When there is no such the liquid dripping prevention means, there is also a possibility that it drops on the photothermographic element, and deteriorates the image quality. In FIG. 9, this type one is shown, and a liquid reservoir  135  is provided on the lower end portion of the accumulation member  132 . 
     Further, the accumulation member is combined with other member, and it can also be made the member having a plurality of functions. In FIG. 10, an example in which the accumulation member is combined with a guide plate  136  to introduce the photothermographic element into the developing section  130 , is shown. 
     Incidentally, the guide members  808  and  809 , and the heat applying means which are explained in the preferred embodiment shown in FIG. 5, may be provided to the example shown in FIGS. 8 to  10 . 
     According to the preferred embodiment, a method by which the foreign matter such as the condensates from gas is not accumulated on the surface of the member inside the heat developing section and the member existing on its periphery, can be provided, and further, the heat developing apparatus and the heat developing method by which, when the surface of the member is structured by an elastic body, the deterioration of the elastic member does not occur, and the inside of the developing section can be easily maintenance-cleaned, can be provided.