Photographic printing apparatus

Abstract: A photographic printing apparatus includes a pause transfer device disposed on a transfer passage between a printing station and a development station for holding temporarily an excess of printed sheets of a photosensitive material over that can be handled by the development station and for transferring printed sheets of the photosensitive material to the development station one after another depending on the condition of developing process.

Description: FIELD OF THE INVENTION The present invention relates to a photographic printing apparatus and more particularly, an apparatus which allows sheets of photosensitive material on which images are printed to be held temporarily before transferred automatically to a development station. BACKGROUND OF THE INVENTION Photographic printing apparatuses are commonly adapted for processing a photosensitive material intermittently at the printing station and continuously at the development station. During the intermittent processing action at the printing station, replacement of a negative film with a new one may be carried out. Even if the printing action at the printing station has been finished, a succeeding one of the photosensitive material sheets cannot be subjected to the printing action before the development action at the development station is completed. Also, during the replacement of the negative film with a new one at the printing station, the development action is inhibited thus disturbing a smooth cycle of the printing and development actions. For compensation, as shown in US-A-4 835 574 a modified apparatus is provided in which an accumulator unit acting as a device for eliminating a difference of operational capability between the two stations to allow more efficient development actions is disposed between the printing station and the development station (see also Japanese Patent Application Publication 2-281255 (1990)). The modified apparatus is designed for processing substantially poster-sized sheets of photosensitive material as holding each of them bent in a loop. If the sheet of photosensitive material is too small or rigid to be looped, it can hardly be handled with the apparatus. The apparatus also allows only a single sheet of the photosensitive material to be held. When two or more of the photosensitive material sheets are to be held, their corresponding number of the accumulator units have to be disposed. This will cause the apparatus to increase its overall size. Other examples of conventional apparatuses are disclosed in US-A-4 601 570, US-A-4 866 472, DE-A-4 235 961, DE-A-3 831 475. It is an object of the present invention, in view of the foregoing predicament, to provide a photographic printing apparatus capable of holding temporarily a desired number of sheets of a photosensitive material in one location without bending them in loops. SUMMARY OF THE INVENTION A photographic pointing apparatus according to the present invention is defined in claim 1. In the photosensitive printing apparatus defined in claim 1, a number of the printed sheets of the photosensitive material processed in the printing station at a high speed regardless of the speed of developing process in the development station are temporarily held in a pause transfer device and will be delivered to the development station according to the speed of the developing process. This allows a difference of time between the printing process and the developing process to be eliminated. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a photographic printing apparatus showing a first embodiment not part of the present invention; Fig. 2 is a front view of a pause transfer device in the first embodiment; Figs. 3 to 6 are explanatory views showing actions of the pause transfer device in the first embodiment; Fig. 7 is a front view of a photographic printing apparatus showing a second embodiment of the present invention; Fig. 8 is an explanatory view showing an action of a pause transfer device in the second embodiment; Fig. 9 is a front view of a photographic printing apparatus showing a third embodiment of the present invention; Fig. 10 to 13 are explanatory views showing actions of the pause transfer device in the third embodiment; Fig. 14 is a front view of a photographic printing apparatus showing a fourth embodiment not part of the present invention; Fig. 15 is an enlarged perspective view showing a portion of the fourth embodiment; Fig. 16 is a front view of a photographic printing apparatus showing a fifth embodiment not part of the present invention; Figs. 17 and 18 are explanatory views showing actions of a pause transfer device in the fifth embodiment; Fig. 19 is a front view of a photographic printing apparatus showing a sixth embodiment not part of the present invention; Figs. 20 and 21 are explanatory views showing actions of a pause transfer device in the sixth embodiment; Fig. 22 is a front view of a photographic printing apparatus showing a seventh embodiment not part of the present invention; Fig. 23 is a cross sectional front view of a suction head in the seventh embodiment; Fig. 24 is a plan view of the suction head in the seventh embodiment; Figs. 25 and 26 are explanatory views showing actions of the suction head in the seventh embodiment; Fig. 27 is a front view of a photographic printing apparatus showing an eighth embodiment not part of the present invention; Fig. 28 is a front view of a photographic printing apparatus showing a ninth embodiment of the present invention; Fig. 29 is an explanatory view showing an action of a pause transfer device in the ninth embodiment; Fig. 30 is a front view of a photographic printing apparatus showing a tenth embodiment not part of the present invention; Fig. 31 is an explanatory view showing an action of a pause transfer device in the tenth embodiment; Fig. 32 is a front view of a photographic printing apparatus showing an eleventh embodiment not part of the present invention; and Fig. 33 is an explanatory view showing an action of a pause transfer device in the eleventh embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Fig. 1 is a schematic view of a photographic printing apparatus not part of the present invention, which comprises a magazine 1a for storage of a roll of photosensitive material, a printing unit 2, a development unit 3, and a pause transfer device 5 disposed across a transfer passage 4 between the printing unit 2 and the development unit 3. The printing unit 2 is provided for printing images in a negative film on sheets of photosensitive material 1 supplied from a feeder 2e where the photosensitive material from its roll in the magazine 1a is cut into sheets of a printing size corresponding to images in a negative film. The printing unit 2 comprises in addition to the feeder 2e a light source 2a, a negative mask 2b, a lens assembly 2c, and an exposure device 2d. The light source 2a includes a lamp, a filter, and a diffusion box. The development unit 3 is adapted for subjecting to a developing process the photosensitive sheets 1 on which images are printed. The development unit 3 comprises a developing tub 3a holding developer liquid, a bleach and fixing tub 3b holding bleach and fixer liquid, two stabilizing tubs 3c and 3d holding stabilizer liquid, and a dryer 3e for drying the developed photosensitive sheet 1. The pause transfer device 5 is provided for temporarily holding an excess of the printed photosensitive sheets 1 which cannot be handled by the development unit 3. The printed photosensitive sheets 1 are fed by the pause transfer device 5 to the development unit 3 in synchronization with the developing process speed. The pause transfer device 5 comprises a pausing means 6 for temporarily holding the transfer movement of the photosensitive sheets 1, a feeding means 7 for feeding the photosensitive sheets 1 to the pausing means 6, and a conveying means 8 for releasing the photosensitive sheets 1 from the pausing means 6. The pausing means 6 has grippers 6c mounted at given intervals to a chain 6b which runs between two sprockets 6a and 6d. The grippers 6c are designed for displacing the photosensitive sheets 1 from their feeding location 9 to their transfer location 10. The gripper 6c comprises a gripper arm 62c having a roller 63c urged by a spring in a gripping direction and a gripper body 61c to which the gripper arm 62c is pivotably mounted. The feeding means 7 is disposed at the feeding location 9 of the pausing means 6 and comprises a drive roller 7a, a press roller 7b, a cam 7c, and a sensor 7d for detecting the photosensitive sheet 1. The movement of the press roller 7b along the peripheral edge of the drive roller 7a is controlled in synchronization with the action of the sprockets 6a and 6d. The sensor 7d detects the leading end of each photosensitive sheet 1 supplied from the development unit 3 and produces a detection signal which in turn instructs the drive roller 7a and the press roller 7b to nip the photosensitive sheet 1 inbetween and transfer it to the gripper 6c. The conveying means 8 comprises a drive roller 8a and a sensor 8b and is located at the transfer location 10 of the pausing means 6. The action of the pause transfer device 5 for temporarily holding and transferring the printed photosensitive sheets 1 to the development unit 3 is as follows: (1) The gripper 6c is moved to the feeding location 9 by the action of the sprocket 6a and its arm 62c is opened by the movement of the cam 7c. (2) In response to the detection signal from the sensor 7d, the press roller 7b is advanced close to the sensor 7d so that the leading end of a photosensitive sheet 1 is nipped between the drive roller 7a and the press roller 7b (Fig, 3). (3) With the photosensitive sheet 1 being nipped, the drive roller 7a is rotated and the press roller 7b is moved to the gripper 6c until the leading end of the photosensitive sheet 1 is accepted in the gripper 6c (Fig. 4). (4) Upon the leading end of the photosensitive sheet 1 reaching the gripper 6c as detected by the sensor 7d, the sprocket 6a is turned to a predetermined angle to release the gripper arm 62c from the cam 7c so that the leading end of the photosensitive sheet 1 is gripped between the arm 62c and the body 61c of the gripper 6c. Meanwhile, the press roller 7b is returned back (to its original location) near the sensor 7d (Fig. 5). (5) The drive roller 7a is rotated again to pass the trailing end of the photosensitive sheet 1 to the pausing means 6 (Fig. 6). (6) By repeating the feeding of the photosensitive sheet 1 to the gripper 6c, a desired number of the photosensitive sheets 1 are held in the pausing means 6. During the feeding action, the tension of the chain 6b is maintained constantly by the movements 61b and 62b of adjusting sprockets 6e and 6f respectively. (7) At the transfer location 10 of the pausing means 6, the gripper arm 62c of the gripper 6c is opened by the action of the drive roller 8a to release the photosensitive sheet 1 (Fig. 2). More particularly, the rotation of the sprocket 6d is stopped at a desired position in response to a detection signal of the sensor 8b indicative of arrival of the photosensitive sheet 1. The photosensitive sheet 1 is then held between the roller 63c of the gripper arm 62c and the drive roller 8a.As the drive roller 8a rotates, the photosensitive sheet 1 is transferred towards the development unit 3 (Fig, 2). Upon the sensor 8b detecting the trailing end of the photosensitive sheet 1, its detection signal actuates the sprocket 6d to rotate again so that the succeeding gripper 6c advances to the transfer location 10 of the pausing means 6 for repeating the same transfer action. (8) By repeating a series of the prescribed actions, any desired number of the photosensitive sheets 1 are temporarily held and transferred in a succession to the development unit 3 where they are subjected to the developing process. The time required for movement of the grippers 6c from the feeding location 9 to the transfer location 10 and the number of the grippers 6c are determined depending on the processing capabilities of the printing unit 2 and the development unit 3. Second Embodiment A photographic printing apparatus of this embodiment is identical in the construction of the printing unit and the development unit to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 7 and 8. Fig. 7 shows the entire of the pause transfer device 5 in which a transfer path 5A is produced between a pair of transfer belts 5a and 50a disposed opposite to each other for transferring a succession of the photosensitive sheets 1. The transfer belts 5a and 50a are mounted to run along drive rollers 5b and 50b disposed at the printing unit 2 side, drive rollers 5c and 50c disposed at the development unit 3 side, transfer rollers 5d and 50d disposed between their respective drive rollers 5b and 5c and 50b and 50c, stationary rollers 5e and 50e disposed outside of the transfer path 5A, and movable tensioning rollers 5f and 50f respectively. The transfer rollers 5d and 50d and the tensioning rollers 5f and 50f are movable in the direction denoted by the arrows in Figs. 7 and 8. When the rollers 5d, 50d, 5f, and 50f are at their home positions, the length of the transfer path 5A is minimum. The transfer belts 5a and 50a are driven by the rollers 5b and 5c and 50b and 50c respectively and their running speeds can be controlled independently. When an initial one of the printed photosensitive sheet 1 is transferred from the printing unit 2 to the development unit 3, the length of the transfer path 50A is kept minimum for passing the photosensitive sheet 1 to the development unit 3 within a minimum length of time. As the initial photosensitive sheet 1 is being fed into the development unit 3, the drive rollers 5c and 50c are rotated at the same speed as of the processing speed in the development unit 3. When the number of the photosensitive sheets 1 processed in the printing unit 2 is increased, the rotation of the drive rollers 5b and 50b at the printing unit 2 side is increased and becomes faster than the rotation of the drive rollers 5c and 50c at to the development unit 3 side. For compensation, the transfer rollers 5d and 50d and the tensioning rollers 5f and 50f are displaced in the direction denoted by the arrows in Fig. 7. Accordingly, the length of the transfer path 5A is increased thus holding a more number of the photosensitive sheets 1 (Fig. 8). In this manner, the transfer of the printed photosensitive sheets 1 to the development unit 3 is controlled depending on the speed of the developing process. When the feeding of the photosensitive sheets 1 from the printing unit 2 is exhausted, the drive rollers 5b and 50b stop their movements while the drive rollers 5c and 50c at the development unit 3 side remain rotating. This causes the transfer rollers 5d and 50d and the tensioning rollers 5f and 50f to move back in the direction denoted by the arrows in Fig. 8 until the length of the transfer path 5A becomes minimum (Fig. 7). Upon the length of the transfer path 5A being minimized, the drive rollers 5b and 50b at the printing unit 2 side restart rotating at the same speed as of the drive rollers 5c and 50c so that all the photosensitive sheets 1 are departed. As shown in Figs. 7 and 8, equal effects may be achieved with no use of the stationary rollers 5e and 50e and the tensioning rollers 5f and 50f. Third Embodiment A photographic printing apparatus of the third embodiment is identical in the construction of the printing and development units to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 9 to 13. The pause transfer device 5 of this embodiment comprises a pausing means 6 for temporarily holding a number of the printed photosensitive sheets 1 while carrying them in grip, a feeding means 7 for feeding the photosensitive sheets 1 to the pausing means 6, a conveying means 8 for transferring the photosensitive sheets 1 from the pausing means 6 to the development unit 3, and a transfer supplementary means 9 (Fig. 9). The pausing means 6 comprises a set of transfer belts arranged opposite to each other; provided at one side is a first transfer belt 61 and at the other side, a second transfer belt 62 and a third transfer belt 63 are disposed to run in an L shape. The first transfer belt 61 is mounted between two stationary rollers 61a. The second and third transfer belts 62, 63 are mounted to run along stationary rollers 62a and 63a respectively and tensioned by movable tensioning rollers 62b and 63b respectively. As the movable tensioning rollers 62b and 63b move in the directions denoted by the arrows, their respective transfer belts 62 and 63 are displaced. The movements of the transfer belts 61, 62, and 63 are controlled in synchronization with the running speed of the printed photosensitive sheets 1 from the printing unit 2. The feeding means 7 comprises a drive roller 71, a press roller 71a, a guide 72, and a feed inlet 73. The guide 72 is designed for guiding the photosensitive sheets 1 from the feed inlet 73 to the entrance of the pausing means 6. The guide 72 has an arcuate guide plate 72a thereof which is mounted pivotably at proximal end to a shaft 72b adjacent to the feed inlet 73 and actuated by a swinging means (not shown) for pivotal movement in the directions denoted by the arrows in Fig. 9. The conveying means 8 comprises two, upper and lower, pairs of transfer belts 81 and 82 mounted between rollers 81a and 81b, and 82a and 82b respectively. One of the two rollers 81a, at the loading side, for the transfer belt 81 is linked to a separation arm 83 mounted for horizontally movement to and from the first transfer belt 61. There is provided a discharge outlet 84 at the unloading side of the two transfer belts 81 and 82. The conveying means 8 also includes a sensor 85 for detecting the loading of the photosensitive sheets 1. The conveying means 8 is adjustable in height with a lifting means (not shown) and at its highest, its discharge output 84 comes to the same height as of the transfer supplementary means 9. The transfer supplementary means 9 comprises a drive roller 9a, a press roller 9b, and a transfer outlet 9c. The action of the pause transfer device 5 is as follows: (1) For feeding a printed photosensitive sheet 1 from the printing unit 2 into the pausing means 6, the guide plate 72a is turned to its substantially horizontal position denoted by the real line in Fig. 9 for guiding until the leading end of the photosensitive sheet 1 moves into between the first transfer belt 61 and the second transfer belt 62. After the feeding of the photosensitive sheet 1 is completed, the guide plate 72a is turned down as denoted by the two-dot chain line in Fig. 9 so that the trailing end of the photosensitive sheet 1 hangs down, (2) Then, the guide plate 72a is turned up to its substantially horizontal position again to feed a succeeding photosensitive sheet 1 into between the first transfer belt 61 and the second transfer belt 62. As the guide plate 72a has been returned back, the succeeding photosensitive sheet 1 is held with its trailing end down. (3) By repeating the above actions, a desired number of the photosensitive sheets 1 are held as overlapped one after another between the first transfer belt 61 and the second transfer belt 62 during its upward movement. The overlap between two adjacent photosensitive sheets 1 may be 5 mm or more. (4) When the photosensitive sheet 1 reaches the conveying means 8, its leading end is detected by the sensor 85 which in turn produces a detection signal. In response to the detection signal, the separation arm 83 is moved towards the transfer belt 61 until it comes above the leading end of the photosensitive sheet 1 (Fig. 10). (5) The conveying means 8 with its separation arm 83 being extracted is then lowered to deflect the leading end of the photosensitive sheet 1 towards the loading end of the conveying means 8 (Fig. 11). (6) As the separation arm 83 is retracted, the conveying means 8 is driven to feed the photosensitive sheet 1 into between the two, upper and lower, belts 81 and 82 (Fig. 12). (7) After the movement of the two transfer belts 81 and 82 is stopped, the conveying means 8 is lifted up to its highest position. The photosensitive sheet 1 is then carried to the development unit 3 by the action of the conveying means 8 and the transfer supplementary means 9 (Fig. 9). (8) By repeating the prescribed actions, the desired number of the photosensitive sheets 1 are held temporarily before transferred to the development unit 3 for developing process. The overlap between two adjacent photosensitive sheets 1 and the transferring speed of the transfer belts 61, 62, and 63 can be controlled depending on the number of the photosensitive sheets 1 in the pause transfer device 5. Fourth Embodiment A photographic printing apparatus of the fourth embodiment not part of the present invention is identical in the construction of the printing and development units to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 14 and 15. Fig. 14 illustrates the entire arrangement of the modified pause transfer device 5. Denoted by 6 is an endless belt 6 comprising a multiplicity of holding plates 6a arranged foldable one over the other at hinges 6b (Fig. 15). The holding plates 6a are made of a synthetic resin material having a resiliency. The length and width of each holding plate 6a are determined corresponding to the measurements size of a maximum sized print sheet. The endless belt 6 is partially stored in its folded form in a housing 7 while the remaining is folded and seated outside the housing 7 for standby. The housing 7 has an inlet 7a and an outlet 7b through which the endless belt 6 runs. It also includes an inlet 7c and an outlet 7d for loading and unloading of the photosensitive sheets 1. At the belt inlet 7a, a belt loader 8 is disposed which comprises a drive roller 8a and a press roller 8b. Similarly, a belt unloader 9 which comprises a drive roller 9a and a press roller 9b is mounted at the belt outlet 7b. Also, at the inlet 7c for the photosensitive sheets 1, a loader means 10 is disposed which comprises a drive roller 10a and a press roller 10b. The loader means 10 is controlled to actuate in synchronization with the loading action of the belt loader 8 for feeding from above and sandwiching the photosensitive sheet 1 between the two holding plates 6a of a stored portion 6A of the endless belt 6 in the housing 7. There is an unloader means 11 which comprises a drive roller 11a and a press roller 11b and is provided at the outlet 7d for the photosensitive sheets 1. The unloader means 11 is controlled to actuate in synchronization with the unloading action of the belt unloader 9 for drawing out the photosensitive sheet 1 from between the two holding plates 6a of the stored portion 6A of the endless belt 6 in the housing 7 and transferring it to the development unit 3. In the pause transfer device 5, the holding plates 6a of the endless belt 6 are traveled as folded and stored partially in the housing 7. More specifically, the holding plate 6a of the stored portion 6A of the endless belt 6 before seated in their folded form outside the housing 7 are moved out from the housing 7 as its lowermost comes first. Meanwhile, a succession of the printed photosensitive sheets 1 from the printing unit 2 are fed into the housing 7 in synchronization with the loading action of the belt loader 8 so that each of them is sandwiched between the two adjacent holding plates 6a of the stored portion 6A of the endless belt 6. The photosensitive sheets 1 are then drawn out one by one from the lowermost of the holding plates 6a of the stored portion 6A of the endless belt 6 in the housing 7 and transferred to the development unit 3. Fifth Embodiment A photographic printing apparatus of the fifth embodiment not part of the present invention is identical in the construction of the printing and development units to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 16 to 18. The modified pause transfer device 5 comprises a pausing means 6, a feeding means 7, a separating means 8, and a conveying means 9 (Fig. 16). The pausing means 6 includes a housing 6a having an inlet 6b and an outlet 6c for temporarily storing a number of the photosensitive sheets 1 in a stack. There is a downwardly sloping plate 6d mounted at the inlet 6c for guiding the photosensitive sheet 1 in a curve. Also, the feeding means 7 is disposed at the inlet 6c and the conveying means 9 is located at the outlet 6c of the pausing means 6. The housing 6a has a bottom thereof tilted as its opposite end (on the right in Fig. 16) slopes down for ease of placing the photosensitive sheet 1 one over the other. The feeding means 7 is designed for feeding the photosensitive sheets 1 into the pausing means 6 and comprises a drive roller 7a and a press roller 7b. The separating means 8 is adapted for separating the lowermost one from a stack of the photosensitive sheets 1 stored in the housing 6a. More specifically, the separating means 8 comprises a suction duct 8b containing a suction fun 8a and extending with its branch ducts 8e and 8f to respectively a far region and a near region of the bottom of the housing 6a of the pausing means 6. The branch ducts 8e and 8f have suction heads 8g and 8h provided at the far ends thereof respectively. The branch duct 8e may be formed of bellows for extension and contraction. Its suction head 8g is arranged for slantwisely downward or retracting movement with a pulling means (not shown). The suction heads 8g and 8h at the far and near regions are located to match the smallest size of the photosensitive sheets 1. The conveying means 9 is adapted for drawing out from the pausing means 6 the leading end of the photosensitive sheet 1 separated by the separating means 8 and feeding it to the development unit 3. The conveying means 9 comprises a drive roller 9a, a press roller 9b, and a transfer guide 9c. The transfer guide 9c is retractably mounted by a drawing means (not shown) to the sloping plate 6d of the housing 6a of the pausing means 6. The press roller 9b is integrally joined to the transfer guide 9c. The action of the pause transfer device 5 is as follows: (1) A succession of the photosensitive sheets 1 from the printing unit 2 are fed by the feeding means 7 into the housing 6a of the pausing means 6 where they are placed one over the other for temporal storage (Fig. 16). (2) The lowermost one of the photosensitive sheets 1 is then sucked at far and near ends with the suction heads 8g and 8h for holding (Fig. 16). Simultaneously, while the transfer guide 9c and the press roller 9b are moved backward, the suction head 8g at the far end is downwardly retracted to pull the leading end of the lowermost photosensitive sheet 1 up to the sloping plate 6d of the pausing means 6 (Fig. 16).As the trailing end of the photosensitive sheet 1 is being held with the suction of the suction head 8h at the near end, it remains not lifted up thus prevent slipping down of the succeeding photosensitive sheet 1. Accordingly, the leading end of the lowermost photosensitive sheet 1 will successfully be separated from the stack of the photosensitive sheets 1. (3) The transfer guide 9c and the press roller 9b are then returned to their original positions so that the lowermost photosensitive sheet 1 is held between the press roller 9b and the drive roller 9a. As the transfer guide 9c is advanced, it comes between the lowermost photosensitive sheet 1 and the stack of the photosensitive sheets 1 (Fig. 17). Finally, the sucking action of the suction heads 8g and 8h is terminated and the drive roller 9a with the press roller 9b is actuated to transfer the photosensitive sheet 1 to the development unit 3 (Fig. 1). Sixth Embodiment A photographic printing apparatus of the sixth embodiment not part of the present invention is identical in the construction of the printing and development units to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 19 to 21. The modified pause transfer device 5 comprises a pausing means 6, a feeding means 7, a separating means 8, and a conveying means 9 (Fig. 19). The action of the pause transfer device 5 of this embodiment is similar to that of the fifth embodiment where the photosensitive sheets 1 are stored in a stack. The sixth embodiment is differentiated from the fifth embodiment by the fact that the photosensitive sheets 1 are placed one after another from beneath and delivered from the uppermost one of them to the development unit 3. The pausing means 6 is adapted for accumulating the photosensitive sheets 1 in a tilted form in its housing 6a. The housing 6a has an inlet 6b provided at the upper of one side thereof and an outlet 6c provided at the lower of the opposite side thereof. Also, a curved plate 6d is mounted extending downwardly slantwisely from the outlet 6c for guiding the discharge of the photosensitive sheets 1. The feeding means 7 is disposed at the inlet 6b of the housing 6a. The outlet 6c is communicated with the conveying means 9. The feeding means 7 comprises a drive roller 7a and a press roller 7b between which each of the photosensitive sheets 1 is nipped and carried. More specifically, as one of the photosensitive sheets 1 from the printing unit 2 is approaching, the press roller 7b remains opposite to the inlet 6b of the pausing means 6 to catch the leading end of the photosensitive sheet 1 (Fig, 19). Then, the press roller 7b is moved towards the inlet 6b in synchronization with the rotating action of the drive roller 7a thus to carry the photosensitive sheet 1 to the inlet 6b of the pausing means 6. The press roller 7b is returned back to the opposite position to the inlet 6b for catching the succeeding photosensitive sheet 1. The separating means 8 is designed for separating the uppermost one from the stack of the photosensitive sheets 1 stored in the housing 6a of the pausing means 6. The separating means 8 comprises a suction duct 8b provided with a suction fan 8a, branch ducts 8e and 8f extending from the suction duct 8b to the housing 6c of the pausing means 6, and suction heads 8g and 8h mounted to the opening ends of the branch ducts 8e and 8f respectively. The branch duct 8e is made of bellows for extension and retraction and its suction head 8g is disposed outside the housing 6a for retracing action with a drawing means (not shown). The two suction heads 8g and 8h are located to match the dimensions of smallest sized one of the photosensitive sheet 1. The conveying means 8 is identical in operational function to that of the fifth embodiment and will be explained in no more details where like components are denoted by like numerals. The action of the pause transfer device 5 of the sixth embodiment is as follows: (1) The leading end of the photosensitive sheet 1 from the printing unit 2 is nipped between the press roller 7b and the drive roller 7a (Fig. 19) and then dragged to the inlet 6b of the pausing means 6 (Fig. 20). (2) Upon the press roller 7b reaching a point adjacent to the inlet 6b, it lifts up the trailing end of the preceding photosensitive sheet 1 in the housing 6a (Fig. 20). As the photosensitive sheet 1 is carried by the action of the drive roller 7a, its leading end moves into the lowermost of the housing 6a of the pausing means 6. (3) By repeating the above actions, the photosensitive sheets 1 are successively accumulated in the housing 6a forming a stack . (4) The uppermost one of the photosensitive sheets 1 in the housing 6a is then separated from the stack by the separating means 8 and further transferred by the conveying means 9 to the development unit 3. Seventh Embodiment A photographic printing apparatus of the seventh embodiment not part of the present invention is identical in the construction of the printing and development units to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 22 to 26. The modified pause transfer device 5 comprises a pausing means 6, a feeding means 7, a separating means 8, and a conveying means 9 (Fig. 22). The pausing means 6 includes a housing 6a having an inlet 6b and an outlet 6c for storage of a stack of the photosensitive sheets 1. Also, a bottom plate 6d is provided for downwardly slantwisely opening at a hinge 6e towards the outlet 6c. The feeding means 7 is disposed at the inlet 6b of the pausing means 6 and the outlet 6c is communicated with the conveying means 9. The bottom of the housing 6a is arranged sloping down towards the far end (to the right in Fig. 22). This allows the photosensitive sheets 1 to be stacked with their leading ends uniform. The feeding means 7 is adapted for feeding the photosensitive sheets 1 into the pausing means 6 and comprises a drive roller 7a and a press roller 7b. The separating means 8 is designed for separating the leading end of the lowermost photosensitive sheet 1 from the stack in the pausing means 6. The separating means 8 comprises a suction duct 8b provided with a suction fan 8a, a flexible duct 8d made of bellows and extending from the suction duct 8b to the far end of the bottom of the housing 6a of the pausing means 6, and a suction head 8f having a suction opening 8e therein and mounted to the opening end of the flexible duct 8d. The upper surface of the suction head 8f is recessed about the suction opening 8e constituting a separation assisting region 8g (Figs. 23 and 24). The suction head 8f is mounted to the bottom plate 6d of the housing 6a of the pausing means 6. The bottom plate 6d and the suction head 8f are driven by a drawing means (not shown) for turning downwardly slantwisely. The conveying means 9 is designed for dragging out the leading end of the lowermost photosensitive sheet 1 separated by the separating means 8 from the pausing means 6 and transferring it to the development unit 3. The conveying means 9 comprises a drive roller 9a, a press roller 9b, and a transfer guide 9c. The transfer guide 9c is arranged for retracting movement in the direction denoted by the arrow with a drawing means (not shown). The transfer guide 9c has a press roller 9b mounted integrally thereto. The action of the pause transfer device 5 of this embodiment is as follows: (1) The photosensitive sheets 1 from the printing unit 2 are fed by the feeding means 7 into the housing 6a of the pausing means 6 where they are placed one over the other for temporary storage (Fig. 22). (2) The lowermost one of the photosensitive sheets 1 is then sucked with the suction head 8f (Fig. 25). Simultaneously, while the transfer guide 9c and the press roller 9b are moved backward, the suction head 8f is downwardly retracted to pull the leading end of the lowermost photosensitive sheet 1 along the bottom plate 6d of the pausing means 6 (Fig. 25).As the leading end of the lowermost photosensitive sheet 1 is sunk to the separation assisting region 8g of the suction head 8f, a flow of air is introduced to between the lowermost photosensitive sheet 1 and the succeeding photosensitive sheet 1 thus separating the two sheets 1 successfully. (3) The transfer guide 9c and the press roller 9b are then returned to their original positions so that the lowermost photosensitive sheet 1 is held between the press roller 9b and the drive roller 9a. As the transfer guide 9c is advanced, it comes between the lowermost photosensitive sheet 1 and the stack of the photosensitive sheets 1 (Fig. 26). Finally, the sucking action of the suction head 8f is canceled and the drive roller 9a with the press roller 9b is actuated to transfer the photosensitive sheet 1 to the development unit 3 (Fig. 26). Eighth Embodiment A photographic printing apparatus of the eighth embodiment not part of the present invention is identical in the construction of the printing and development units to that of the f irst embodiment. The, pause transfer device 5 between the printing unit and the development unit is however modified as shown in Fig. 27. The modified pause transfer device 5 comprises a pausing means 6, a feeding means 7, a separating means 8, and a conveying means 9. The pause transfer device 5 of this embodiment is similar to that of the sixth embodiment where the printed photosensitive sheets 1 are placed one after another from beneath for storage and delivered to the development unit 3 in a succession from above. The pausing means 6 is adapted for accumulating the photosensitive sheets 1 in a tilted form in its housing 6a. The housing 6a has an inlet 6b provided at the upper of one side thereof and an outlet 6c provided at the lower of the opposite side thereof. Also, a lower plate 6d is provided with a hinge 6e so that it can be bent outwardly of the outlet 6c. The feeding means 7 is disposed at the inlet 6b of the housing 6a and the outlet 6c is communicated with the conveying means 9. The separating means 8 is designed for separating the uppermost one from the stack of the photosensitive sheets 1 stored in the housing 6a of the pausing means 6. The separating means 8 comprises a suction duct 8b provided with a suction fan 8a, a flexible duct 8d made of bellows and extending from the suction duct 8b to a lower region of the opposite side of the housing 6c of the pausing means 6, and a suction head 8f having a suction opening 8e therein and mounted to the opening end of the flexible duct 8d. The upper surface of the suction head 8f is recessed about the suction opening 8e constituting a separation assisting region 8g. The suction head 8f is mounted to the lower plate 6d of the housing 6a of the pausing means 6. The lower plate 6d and the suction head 8f are driven by a drawing means (not shown) for turning outwardly. The feeding means 7 and the conveying means 9 are identical in operational function to those of the sixth and seventh embodiments respectively and will be explained in no more details where like components are denoted by like numerals. In the action of the pause transfer device 5 of the eighth embodiment, the printed photosensitive sheets 1 are accumulated in a succession in the housing 6a of the pausing means 6 as described in the sixth embodiment. The stack of the photosensitive sheets 1 are then released one after another from above by the separating means 8 and transferred by the conveying means 9 to the development unit 3. Ninth Embodiment A photographic printing apparatus of the ninth embodiment is identical in the construction of the printing and development units to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 28 and 29. Fig. 28 illustrates the entire arrangement of the modified pause transfer device 5, in which a transfer path 5A for holding a plurality of the photosensitive sheets 1 extends between a pair of transfer belts 5a and 50a arranged in parallel. A succession of the photosensitive sheets 1 are temporarily held along the transfer path 5A as desired. The transfer belt 5a (an idler belt) is mounted to run along a press roller 5b disposed at the printing unit 2 side, a press roller 5c disposed at the development unit 3 side, tensioning rollers 5d between the two press rollers 5b and 5c, and a group of stationary tensioning rollers 5e and movable tensioning rollers 5f disposed outside of the transfer path 5A. Similarly, the transfer belt 50a (a driver belt) is mounted to run along a drive roller 50b disposed at the printing unit 2 side, a drive roller 50c disposed at the development unit 3 side, tensioning rollers 50d between the two drive rollers 50b and 50c, and a group of stationary tensioning rollers 50e and movable tensioning rollers 50f disposed outside of the transfer path 5A. The tensioning rollers 5d, 50d, 5f, and 50f are arranged movable in the directions denoted by the arrows in Fig. 28. The tensioning rollers 5d and 50d are urged by spring in the directions of the arrows while the tensioning roller 5f and 50f are urged in the directions opposite to the arrow directions. It is assumed that when the movable rollers are at their home positions, the length of the transfer path 5A is minimum. As the tensioning rollers 5d and 50d depart from their home positions, shown in Fig. 28, the transfer path 5A is extended in the length having multiple turns T. The rotating speeds of the drive rollers 50b and 50c at the printing unit 2 side and the development unit 3 side respectively are varied independently. The rotating actions of the drive rollers 50b and 50c and the transfer speed of the transfer belts 5a and 50a are controlled with a controller (not shown) connected to a drive circuit for the drive rollers 50b and 50c. At the time when the transfer of the printed photosensitive sheets 1 from the printing unit 2 to the development unit 3 is commenced, the length of the transfer path 5A is kept minimum for optimum transfer as shown in Fig. 28. More specifically, as the first one of the photosensitive sheets 1 is transferred to the development unit 3, its speed is identical to the processing speed in the development unit 3. When the number of the photosensitive sheets 1 after the printing process is increased, the feeding speed determined by the drive roller 50b at the printing unit 2 side becomes greater than the transfer speed controlled by the drive roller 50c at the development unit 3 side. Accordingly, the movable tensioning rollers 5d, 50d, 5f, and 50f are moved in the directions of the arrows shown in Fig. 28. This allows the length of the transfer path 5A to increase thus holding a more number of the photosensitive sheets 1 (Fig. 29). Then, the photosensitive sheets 1 are delivered one after another to the development unit 3 according to the speed of the developing process. When the supply of the photosensitive sheets 1 from the printing unit 2 is exhausted, the drive roller 50b at the printing unit 2 side stops rotating while the drive roller 50c at the development unit 3 remains rotating. Accordingly, the movable tensioning rollers 5d, 50d, 5f, and 50f are returned to their home positions and the length of the transfer path 5A becomes minimum again (Fig. 28). With a minimum length of the transfer path 5A, the drive roller 50b at the printing unit 2 side rotates at the same speed as of the drive roller 50c at the development unit 3 side to carry the photosensitive sheets 1 through the development unit 3 with no delay. Although the tensioning rollers 5d and 50d in this embodiment are movable relatively, it is possible to allow either the rollers 5d or 50d to be moved to form turns T while the others being fixed. Also, equal effects may be achieved without the stationary roller 5e and 50e and the tensioning rollers 5f and 50f. Tenth Embodiment A photographic printing apparatus of the tenth embodiment not part of the present invention is identical in the construction of the printing and development units to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 30 and 31. Fig. 30 illustrates the entire arrangement of the modified pause transfer device 5. As shown, a transfer path 5A for holding a plurality of the photosensitive sheets 1 comprises a transfer belt 50a, transfer guide assemblies 5B and 5C disposed along the transfer belt 50a, and turn assemblies 5D. The transfer belt 50a is mounted to run along a drive roller 50b disposed at the printing unit 2 side, a drive roller 50c disposed at the development unit 3 side, tensioning rollers 50d between the two drive rollers 50b and 50c, and a group of stationary tensioning rollers 50e and movable tensioning rollers 50f disposed outside of the transfer path 5A. The turn assembly 5D comprises a pair of press rollers 51D and a guide plate 52D disposed between the press rollers 51D. The guide plate 52D is formed of an arcuate shape extending along the transfer belt 50a. The transfer guide assembly 58 comprises a press roller 51B, guide rollers 52B, and guide plates 53B and 54B which all are aligned. Similarly, the transfer guide assembly 5C comprises a press roller 51C, guide rollers 52C, and guide plates 53C which all are aligned. The press rollers 51D, 51B, and 51C are separated from each other by a distance smaller than the transfer distance of the photosensitive sheets 1. The tensioning rollers 50d and the turn assemblies 5D are movable in the direction denoted by the arrows in Fig. 30 and in its opposite direction. The tensioning rollers 50f are also movable in the direction denoted by the arrows in Fig. 30 and in its opposite direction. The tensioning rollers 50d and the turn assemblies 5D are urged by spring in the direction of the arrow in Fig. 30 while the tensioning rollers 50f remain urged in the opposite direction. Also, it is arranged that the length of the transfer path 5A is minimum when the movable rollers stay at their home positions. When the tensioning rollers 50d and the turn assemblies 5D are moved away from their home positions, the length of the transfer path 5A becomes greater with its turns T departing from each other (Fig. 31). As the result, a more number of the photosensitive sheets 1 will be held before transferred one after another to the development unit 3 according to the speed of the developing process. The rotating speeds of the drive rollers 50b and 50c at the printing unit 2 side and the development unit 3 side respectively are varied independently. The rotating actions of the drive rollers 50b and 50c and the transfer speed of the transfer belt 50a are controlled with a controller (not shown) connected to a drive circuit for the drive rollers 50b and 50c. At the time when the transfer of the printed photosensitive sheets 1 from the printing unit 2 to the development unit 3 is commenced, the length of the transfer path 5A is kept minimum for optimum transfer as shown in Fig. 30. More specifically, as the first one of the photosensitive sheets 1 is transferred to the development unit 3, its speed is identical to the processing speed in the development unit 3. When the number of the photosensitive sheets 1 after the printing process is increased, the feeding speed determined by the drive roller 50b at the printing unit 2 side becomes greater than the transfer speed controlled by the drive roller 50c at the development unit 3 side. Accordingly, the movable tensioning rollers 50d, turn assemblies 5D, and tensioning rollers 50f are moved in the directions of the arrows shown in Fig. 30. This allows the length of the transfer path 5A to increase thus holding a more number of the photosensitive sheets 1 (Fig. 31). Then, the photosensitive sheets 1 are delivered one after another to the development unit 3 according to the speed of the developing process. When the supply of the photosensitive sheets 1 from the printing unit 2 is exhausted, the drive roller 50b at the printing unit 2 side stops rotating while the drive roller 50c at the development unit 3 remains rotating. Accordingly, the movable tensioning rollers 50d and 50f and turn assemblies 5D are returned to their home positions and the length of the transfer path 5A becomes minimum (Fig. 30). With a minimum length of the transfer path 5A, the drive roller 50b at the printing unit 2 side rotates at the same speed as of the drive roller 50c at the development unit 3 side to carry the photosensitive sheets 1 through the development unit 3 with no delay. Also, equal effects may be achieved without the stationary roller 50e and the tensioning rollers 50f. Eleventh Embodiment A photographic printing apparatus of the eleventh embodiment not part of the present invention is identical in the construction of the printing and development units to that of the first embodiment. The pause transfer device 5 between the printing unit and the development unit is however modified as shown in Figs. 32 and 33. The arrangement of this embodiment is identical to that of the tenth embodiment except the turn assemblies 5D and its explanation will not be repeated as like components are denoted by like numerals. The turn assembly 5D of the eleventh embodiment comprises rollers 51D and a turn belt 52D mounted to run along the rollers 51D in a curved loop, as shown in Fig. 32. The tensioning rollers 50d and the turn assemblies 5D are movable in the direction denoted by the arrows in Fig. 32 and in its opposite direction. Also, the tensioning rollers 50d and the turn assemblies 5D remain urged by spring in the direction of the arrow. When the tensioning rollers 50d and the turn assemblies 5D are moved away f rom the minimum of the transfer path 5A, the length of the transfer path 5A becomes greater with its turns T departing from each other (Fig. 33). At the time when the transfer of the printed photosensitive sheets 1 from the printing unit 2 to the development unit 3 is commenced, the length of the transfer path 5A is kept minimum for optimum transfer as shown in Fig. 32. More specifically, as the first one of the photosensitive sheets 1 is transferred to the development unit 3, its speed is identical to the processing speed in the development unit 3. When the number of the photosensitive sheets 1 after the printing process is increased, the feeding speed determined by the drive roller 50b at the printing unit 2 side becomes greater than the transfer speed controlled by the drive roller 50c at the development unit 3 side. Accordingly, the movable tensioning rollers 50d, turn assemblies 5D, and tensioning rollers 50f are moved in the directions of the arrows shown in Fig. 32. This allows the length of the transfer path 5A to increase thus holding a more number of the photosensitive sheets 1 (Fig. 33). Then, the photosensitive sheets 1 are delivered one after another to the development unit 3 according to the speed of the developing process. When the supply of the photosensitive sheets 1 from the printing unit 2 is exhausted, the drive roller 50b at the printing unit 2 side stops rotating while the drive roller 50c at the development unit 3 remains rotating. Accordingly, the movable tensioning rollers 50d and 50f and turn assemblies 5D are returned to their home positions and the length of the transfer path 5A becomes minimum again (Fig. 32). With a minimum length of the transfer path 5A, the drive roller 50b at the printing unit 2 side rotates at the same speed as of the drive roller 50c at the development unit 3 side to carry the photosensitive sheets 1 through the development unit 3 with no delay. Also, equal effects may be achieved without the stationary roller 50e and the tensioning rollers 50f. It would be understood that the number of the photosensitive sheets to be held in the pause transfer device 8 of any of the first to eleventh embodiments is at least four or more. Also, the number of the photosensitive sheets 1 may be varied depending on the speed of the developing process.

Claims: A photographic printing apparatus including a printing station (2) and a development station (3) and a pause transfer device (5) disposed on a transfer passage (4) between the printing station (2) and the development station (3) for holding temporarily an excess of printed sheets (1) of a photosensitive material over that can be handled by the development station and for transferring printed sheets of the photosensitive material to the development station one after another depending on the condition of developing process, the pause transfer device (5) comprises: a pausing means (6) for holding the printed sheets of the photosensitive material; a feeding means (7) for guiding the printed sheets of the photosensitive material to a feeding location of the pausing means (6) where they are held one after another by the holding means; a conveying means (8) for releasing the printed sheets of the photosensitive material from their respective holding means which have been carried from the feeding location to a transfer point and delivering them to the development station, the pausing means (6) includes two endless belts (5a, 50a) disposed opposite for each other defining a transfer path (5A), whereby the number of printed sheets temporarily held between said endless belts inside the pausing means is adjustable and is determined corresponding to the excess of the printed sheets of the photosensitive material that cannot be handled by the development station (3), characterised in that : the pausing means comprises a holding adjusting means for controlling the length of the transfer path to and from a minimum length by providing and moving turns across the two endless belts, the turns of the transfer path (5A) are generated and moved by means of a combination of roller guides (5b, 50b, 5f, 50f) and vertically movable press rollers (5d, 50d) aligned along the endless belts; and the turns are provided by folding the endless belts by means of moving said press rollers against the belts; the folding of the endless belts is such that the number of the printed sheets of the photographic material to be temporarily held in the pausing means (6) is at least four. A photographic printing apparatus according to claim 1, wherein the number of the printed sheets of the photosensitive material to be temporarily held in the pausing means (6) is determined depending on the relation between a time interval required for replacement of a negative film in the printing station (2) and the efficiency of developing process in the development station (3).

Inventors: NISHIKAWA HIDETOSHI, SHIMA KAZUNOBU, YAMAMOTO YUJI, NISHIKAWA, HIDETOSHI, SHIMA, KAZUNOBU, YAMAMOTO, YUJI, Nishikawa, Hidetoshi, c/o Noritsu Koki Co. Ltd., Shima, Kazunobu, c/o Noritsu Koki Co. Ltd., YAMAMOTO, YUJI, C/O NORITSU KOKI CO. LTD.
Applicants: NORITSU KOKI CO LTD, NORITSU KOKI CO., LTD.
Application year: 1995
Main classification: G03D13
IPC codes: B65H5, G03D13, G03B27