A conveyance direction changing device of a photosensitive material in an automatic developing apparatus

Abstract: [Object] To provide a changing device for changing a conveyance direction of a photosensitive material without causing it to move in a zigzag manner. [Solution] A portion of an endless belt 12 is brought into contact with a lower part of the outer surface of a turn roller 11. A tubular elastic member 16 is fitted in the middle of the turn roller 11 with respect to its widthwise direction. A photosensitive material A fed between the turn roller 11 and the belt 12 by the rotation of the turn roller 11 and the movement of the belt 12 is conveyed in a circumferential direction of the turn roller 11 with tightly held between the belt 12 and the elastic member 16. The photosensitive material A can have its conveyance direction changed without being caused to move in a zigzag manner by the elastic member 16 substantially evenly in contact therewith over the entire width thereof.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a conveyance direction changing device for changing a conveyance direction of a photosensitive material in an automatic developing apparatus for developing the photosensitive material such as a photographic film and a photographic paper. Description of the Prior Art In an automatic developing apparatus in which a variety of development solutions including a liquid developer, a liquid fixer and a liquid stabilizer are filled in treatment tanks and photosensitive materials are successively conveyed into the development solutions in the treatment tanks, racks are suspended in the respective treatment tanks and the photosensitive materials are conveyed in these racks. Each rack is provided with a conveying device for the photosensitive material. The photosensitive material is conveyed, faced down, by the conveying device and has its conveyance direction changed by 180° by a conveyance direction changing mechanism provided at a bottom part of the rack so as to be conveyed, faced up. A known conveyance direction changing mechanism is shown in FIG. 5. This mechanism is constructed such that feed rollers 31, 32, 33 are arranged in contact with the opposite sides and bottom of a turn roller 30 drivingly rotated, arcuate guides 34 are provided between adjacent feed rollers 31, 32, 33, and a photosensitive material A fed to a contact portion between the turn roller 30 and the feed roller 31 at one side has its conveyance direction changed by 180° along a lower part of the outer surface of the turn roller 30 by the rotation of the turn roller 30 and the feed rollers 31, 32, 33. Since the photosensitive material A is conveyed along the fixed guides 34 in the above conveyance direction changing mechanism, it is likely to be scratched by the contact with the guides 34, thereby presenting a problem of its inability to provide good quality products. In order to solve the above problem, the applicant of the present invention proposed a conveyance direction changing device having a little likelihood of scratching the photosensitive material in Japanese Unexamined Patent Publication No. 8-339071. FIG. 6 shows the conveyance direction changing device disclosed in the above publication. This device is constructed such that an endless belt 41 having a portion thereof held in contact with a lower part of the outer surface of a turn roller 40 rotated in one direction is moved in a direction of arrow at the same speed as the circumferential speed of the turn roller 40 to convey a photosensitive material A fed between a contact portion between the belt 41 and the turn roller 40 in a circumferential direction of the turn roller 40 while being tightly held between the turn roller 40 and the belt 41. Since the photosensitive material A is tightly held between the turn roller 40 and the belt 41 in the above conveyance direction changing device, it can have its conveyance direction changed without being damaged. In the above device, the turn roller 40 and a plurality of belt rollers 42 for guiding the movement of the belt 41 are not necessarily precise rollers having an outer diameter uniform over the entire length. With the use of imprecisely dimensioned rollers or a mount error of the rollers, the belt 41 cannot evenly be brought into contact with the turn roller 40 over the entire width. Here, if a contact pressure between the turn roller 40 and the belt 41 is uneven along the widthwise direction of the belt 41, the photosensitive material A conveyed while being tightly held between the turn roller 40 and the belt 41 slips in positions where the contact pressure is low. As a result, the photosensitive material A moves in a zigzag manner and the side edges thereof may be strongly brought into contact with side guides for guiding the movement of the side edges of the photosensitive material A, thereby being scratched. This disadvantageously results in a considerable reduction in product value. DE 196 14 341 A1 discloses a device for changing a conveyance direction of a photosensitive material comprising an endless belt having a portion thereof held in contact with a lower part of the outer surface of a turn roller. The photosensitive material is conveyed between the turn roller and the endless belt. On the surface of the endless belt opposite to the photosensitive material guiding projections are provided on the outer edges of the belt. By this projections the belt is guided on a roller driving the endless belt. US 4,181,421 and DE 27 39 542 A1 disclose similar devices in which a photosensitive material is guided between a turn roller and an endless belt. It is the object of the invention to provide a device for changing a conveyance direction of a photosensitive material in an automatic developing apparatus without causing it to move in a zigzag manner in the changing device, which can avoid a scratching of the photosensitive material. This object is solved by a device having the features defined in claim 1. Preferred embodiments are defined in the dependent subclaims. SUMMARY OF THE INVENTION The device for changing a conveyance direction of a photosensitive material in an automatic developing apparatus, according to the present invention, is defined in claim 1. Preferably, the outer diameter of the large diameter portion is about 1.15 to 1.2 times that of the turn roller in order to effectively prevent the photosensitive material from moving in a zigzag manner. If the opposite ends of the outer surface of the large diameter portion are edged, these edges may be strongly brought into contact with the photosensitive material, thereby scratching it. Accordingly, the opposite ends of the large diameter portion. The large diameter portion may be formed by fitting a tubular elastic member having a chemical resistance on the turn roller which has the same diameter over the entire length are beveled. Materials for the elastic member include silicone rubber, fluororubber, ethylene rubber, soft vinyl chloride resin, and elastomer. If a fine uneven portion is formed on the entire outer surface of the tubular elastic member, a frictional resistance to the photosensitive material is enhanced. As a result, the photosensitive material can securely be conveyed without slipping. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a rack provided with a conveyance direction changing device according to the invention, FIG. 2 is a perspective view of the conveyance direction changing device, FIG. 3 is a section of the conveyance direction changing device, FIG. 4 is a section enlargedly showing a part of the conveyance direction changing device, FIG. 5 is a schematic diagram of a prior art conveyance direction changing device, and FIG. 6 is a schematic diagram of another prior art conveyance direction changing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereafter, one embodiment of the invention is described with reference to FIGS. 1 to 4. FIG. 1 schematically shows a rack 1 for conveying a photosensitive material which is suspended in a treatment tank of an automatic developing apparatus. The rack 1 is provided at its upper part with a pair of feed roller 2 for conveying a photosensitive material A, faced down, by their rotation. At one side of a conveyance path of the photosensitive material A is provided an intermediate conveyance roller 3. Pressing rollers 4a, 4b are in contact with the opposite sides of the intermediate conveyance roller 3. The intermediate conveyance roller 3 and the pressing rollers 4a, 4b are rotated in directions of arrow of FIG. 1 and the photosensitive material A is further conveyed downward by the intermediate conveyance roller 3 and the pressing roller 4a. At a bottom part of the rack 1 is provided a changing device 10 for changing a conveyance direction of the photosensitive material A by 180°. The photosensitive material having its conveyance direction changed by the changing device 10 is conveyed, faced up, by the intermediate conveyance roller 3 and the pressing roller 4b, and is discharged from the rack 1 by a pair of discharge rollers 5 provided at the upper part of the rack 1. Along the conveyance path of the photosensitive material A are provided side guides 6 for guiding the movement of the side edges of the photosensitive material A. FIGS. 2 to 4 show in detail the changing device 10 for changing the conveyance direction of the photosensitive material A. The changing device 10 is comprised of a turn roller 11 and an endless belt 12. A gear 13 mounted on an end of a shaft of the turn roller 11, and a bevel gear portion 13a thereof is in mesh with a bevel gear 15 on a drive shaft 14 arranged at a right angle to the turn roller 11. The turn roller 11 is rotated in a direction of arrow of FIG. 3 by the rotation of the drive shaft 14. A large diameter portion 16 is provided in the middle of the turn roller 11 with respect to its widthwise direction. The large diameter portion 16 is made from a tubular elastic member and is secured to the turn roller 11 by an adhesive means. The elastic member 16 is made of silicone rubber, fluororubber, ethylene rubber, soft vinyl chloride resin, elastomer, or the like and has a chemical resistance. The outer diameter of the elastic member 16 is about 1.15 to 1.2 times that of the turn roller 11, and the length thereof is about 1/5 of the length of the turn roller 11. As shown in FIG. 4, bevelled portions 17 are formed at the opposite longitudinal ends of the elastic member 16. The bevelled portions 17 may be slanted or rounded. Further, a fine uneven portion 18 is formed on the outer surface of the elastic member 16 over its entire width. The belt 12 has a width substantially equal to the length of the turn roller 11 and is made of a material having a chemical resistance such as silicone rubber, polypropylene, polyvinyl chloride, polyphenylene oxide, polyethylene, or epoxy resin. A conductive belt formed by covering the surface of a fabric made of polyester with Mirabl urethane (MPU), nitrile rubber (NBR) or chloroprene rubber (CR) may be used as the belt 12. The belt 12 is fitted on three belt rollers 19 such that a portion thereof is in contact with a lower part of the outer surface of the tubular elastic member 16. On one end of each of the belt rollers 19 arranged at the opposite sides of the turn roller 11 is mounted a spur gear 20 in mesh with a spur gear portion 13b of the gear 13 to transmit the rotation of the turn roller 11. As a result, the belt 12 is moved in a direction of arrow of FIG. 3. When the photosensitive material A is fed between the turn roller 11 and the belt 12 while the turn roller 11 is rotated and the belt 12 is moved, it is conveyed in a circumferential direction of the turn roller 11 with tightly held between the elastic member 16 and the belt 12, thereby having the conveyance direction thereof changed. The photosensitive material A after the change of the conveyance direction is conveyed upward between the belt 12 and the elastic member 16 while the opposite side edges thereof is guided by the side guides 6 shown in FIG. 1. Since the tubular elastic member 16 for tightly holding the photosensitive material A is provided in the middle of the turn roller 11 with respect to its widthwise direction and is itself elastic, it is substantially evenly in contact with the photosensitive material A over its entire width. Thus, the photosensitive material A can have its conveyance direction changed without being moved in a zigzag manner and an undesirable event where the side edges of the photosensitive material A are strongly brought into contact with the side guides 6 does not occur. Further, since the bevelled portions 17 are formed at the opposite ends of the elastic member 16, these ends are not strongly brought into contact with the photosensitive material A, thereby preventing the photosensitive material A from being scratched. As described above, according to the invention, a contact pressure to the photosensitive material can be made substantially uniform over the entire width of the turn roller by providing the large diameter portion in the middle of the turn roller with respect to its widthwise direction. Further, the application of bevelling to the opposite ends of the outer surface of the large diameter portion prevents these ends from being strongly brought into contact with the photosensitive material, which in turn prevents linear scratches from being made in the photosensitive material. Furthermore, a contact pressure to the photosensitive material can be made more uniform by forming the large diameter portion by the tubular elastic member. This can effectively prevent the photosensitive material from moving in a zigzag manner and also a relative slip of the photosensitive material with respect to the large diameter portion. Further, the relative slip of the photosensitive material can more effectively be prevented by forming the fine uneven portion on the entire outer surface of the elastic member. LIST OF REFERENCE NUMERALS 11 Turn Roller 12 Belt 16 Large Diameter Portion (Elastic Member) 17 Bevelled Portion 18 Uneven Portion

Claims: A device (10) for changing a conveyance direction of a photosensitive material (A) in an automatic developing apparatus, in which device the photosensitive material (A) is tightly held between a turn roller (11) which is drivingly rotated and an endless belt (12) which is mounted such that a portion thereof is in contact with substantially the half of the outer surface of the turn roller (11) and the conveyance direction of the photosensitive material is changed along the outer surface of the turn roller by the rotation of the turn roller (11) and the movement of the belt (18), characterized in that a predefined, elastic larger diameter portion (16) is provided in the middle of a turn roller (12) with respect to its widthwise direction so as to be evenly in contact with the photosensitive material, and a bevelling (17) is applied to the opposite ends of the outer surface of the larger diameter portion (16). A conveyance direction changing device according to claim 1, wherein the outer diameter of the larger diameter portion (16) is about 1.15 to 1.2 times that of the turn roller (11). A conveyance direction changing device according to claim 1 or 2, wherein the larger diameter portion comprises a tubular elastic member (16) mounted on the turn roller (11) and having a chemical resistance. A conveyance direction changing device according to claim 3, wherein the tubular elastic member (16) is made of one kind of silicone rubber, fluororubber, ethylene rubber, soft vinyl chloride resin, or elastomer. A conveyance direction changing device according to claim 3 or 4, wherein a fine uneven portion is formed on the entire outer surface of the tubular elastic member (16).

Inventors: TAMAKI YOSHIKUZA, TAMAKI, YOSHIKUZA
Applicants: NORITSU KOKI CO LTD, NORITSU KOKI CO., LTD.
Application year: 1998
Main classification: G03D3
IPC codes: G03D3