Method for forwarding and rewinding photosensitive material

Abstract: A method for forwarding a photosensitive material (P) in a photoprocessing apparatus in which the photosensitive material is forwarded from a magazine (1A) for storing the photosensitive material (P) wound in a form of roll for treatment, characterized by providing a plurality of forwarding speeds of the photosensitive material (P). The paper is forwarded at a low speed at the start of forwarding, and conversely it is stopped from the low-speed state when the forwarding is stopped, so that slack inside the magazine (1A) can be absorbed and at the same time, slack is not generated inside the magazine. Consequently, abnormal noise or damage to paper (P) generated from the magazine (1A) inside is eliminated. A method for rewinding photosensitive material in the magazine (1A) is also disclosed.

Description: The present invention relates to a method for rewinding photosensitive material (hereinafter simply referred to "rewinding method") in a photo-processing apparatus, and more particularly to a method for rewinding unexposed photosensitive material around a magazine from the printing part of the photo-processing apparatus. For a photo-processing apparatus, there is an apparatus which forwards a photographic paper (paper) as photosensitive material from a magazine which stores the paper in a form of roll, prints images recorded on the developed film, develops the paper with the images printed, and then after drying the paper, cuts it into a specified size for every frame. In forwarding the paper, the apparatus provides friction (load) to the magazine core to prevent excessive rotation of a paper roll, and rotates the paper roll while synchronizing the paper forwarding mechanism. However, because the inertia working on the paper varies in accordance with the paper rewinding diameter when paper is being forwarded, it is difficult to set friction, causing problems that excessively heavy friction allows excessively large load to work on the motor for providing rotation to the paper core and motor durability lowers. On the contrary, excessively light friction of the core causes the paper to slack in the magazine. Forwarding the slacked paper as it is at a high speed causes a problem that abnormal "pow" noise is generated when paper finishes stretching. On the other hand, in the photo-processing apparatus, the magazine is replaced when paper width or material is chosen. When the magazine is replaced, the paper of an unexposed part forwarded from the magazine is rewound into the magazine until a paper tip end slightly protrudes from a light shielding slit of the magazine by rotation of the core (Japanese Examined Utility Model Publication No. 12990/1995). The rewinding of the paper by the core does not cause any problem when the paper core is small. However, there is a case in which the paper core is increased by increasing the paper length in order to reduce the paper replacing frequency. In such case, since a large inertia is applied to the paper when the paper is rewound, it is difficult to stop the paper tip end in front of the light-shielding slit so that the tip end is held inside the magazine. When the paper is held inside the magazine, the magazine must be detached from the photo-processing apparatus, and the paper tip end must be pulled out from the magazine light shielding slit to set the paper tip end again in a protruding condition. US-4 327 878 suggests a generic method of rewinding a photosensitive material in a photo-processing apparatus, in which the photosensitive material is forwarded from the magazine for storing the photosensitive material wound in a form of roll for treatment. An operating speed of a motor is controlled in accordance to a sensed velocity of a print paper. US-4 115 817; US-3 893 360 and DE 31 51 932 A2 each disclose an apparatus for forwardly feeding a recording material. Accordingly, it is an object of the present invention to provide a rewinding method which can accurately stop a tip end of an unexposed photosensitive material in front of the magazine. In accordance with the present invention, there is provided a method of rewinding a photosensitive material in a photo-processing apparatus as defined in the claim. Fig. 1 is an explanatory view showing a photo-processing apparatus related to the rewinding method according to the present invention; and Fig. 2 is an explanatory view showing operation of the rewinding method according to the present invention. Referring now to the accompanying drawings, the forwarding method and the rewinding method according to the present invention will be described in detail. Fig. 1 is an explanatory view showing a photo-processing apparatus related to the forwarding method. The forwarding method is, for example, applied to the photo-processing apparatus shown in Fig. 1. Such photo-processing apparatus is equipped with a printing part 2 for forwarding paper P from a magazine storing paper P in a form of roll and printing image information recorded on the developed film to this paper, a developing part 3 for developing the printed paper P, a drying part 4 for drying the developed paper P, and a cutting part 5 for cutting the dried paper P into a specified size for every frame. To this photo-processing apparatus, two magazines 1a, 1b are set. This is to reduce load of magazine replacement work and improve work efficiency by automatically switching to paper P of the other magazine 1b when paper P of one magazine 1a is exhausted or paper is changed to that of different width or kind. However, in the present invention, the number of magazines is not restricted to two. The magazine 1a is housed in a light-shielded casing, and paper P pulled out from the inside of magazine 1a is forwarded by a forwarding mechanism A comprising a pair of conveying rollers 6a, 6b and a driving motor 7 for rotating and driving the conveying roller 6a to be fed to the printing part 2. Next, the forwarding method will be described. The paper forwarded from the magazine is designed to be looped temporarily and then fed to the printing part. This is to reduce the forwarding speed of the driving motor 7 at the start and the stop of paper forwarding independently from other conveying motor by forming a loop. First, as shown in Fig. 1, the tip end of paper P stored in the magazine 1a is pulled out and inserted between a pair of conveying rollers 6a, 6b of the forwarding mechanism A. Then, at a low speed (for example, 250 mm/sec), paper P is allowed to pass a loop mechanism B and is fed, for example, by 100 mm after the sensor S is shaded, with a loop forming amount by dead weight later described taken into account, and then the forwarding of paper P is stopped. Because paper P is forwarded at a low speed in this event, it is possible to absorb the slacking portion inside the magazine 1a and prevent abnormal noise or damage to paper, and because paper P is stopped at a low speed, inertia of paper roll (core) 8 can be lowered and slack of paper P inside the magazine 1a can be eliminated. Then, a motor 9 of the loop mechanism B is driven to rotate and move the conveying roller 10 and conveying guide 11 in the arrow C direction. This rotational movement allows paper P to form a loop LO by its dead weight. Then, a crimping solenoid 12 operates to hold paper P. Thereafter, the driving motor 7 is driven to forward paper P, allowing loop L2 to be formed until a sensor S2 is shaded. The paper P forwarding speed in this event can be designed to be high speed (for example, 650 mm/sec) because paper P is stopped at a low speed so that paper P in the magazine 1a is free from slackness. After the loop L2 is formed, the paper forwarding speed returns to a low speed, and then, conveying rollers 14, 15 are driven at a slow speed (for example, 180 mm/sec) to forward the paper P tip end to the position of conveying roller 16. To the paper thus forwarded, film image information is printed every frame in the printing part 2. Because the forwarding speed at a low speed by the forwarding mechanism A is designed to be larger than the conveying speed at a low speed by the conveying motor 13, the sensor S3 is certain to be shaded at the start of forwarding. When the sensor S3 is shaded by paper P in the form of loop, forwarding of paper P is stopped at a low speed. Then, the paper is successively conveyed with conveying rollers and the driving motor 7 is kept stopped even when the sensor S3 becomes transmissible, and when the sensor S2 becomes transmissible, forwarding of paper P is switched from stop to low speed. Till the tip end of paper P enters between conveying rollers 18 via the conveying roller 17, the forwarding accuracy must be improved for preventing slack and bulging of paper, accurately positioning the paper to the exposing position as well as forming punch holes with good positional accuracy. For this purpose, the paper P conveying speed by the conveying motor 13 is designed to be slower than the forwarding speed (250 mm/sec) of paper P, for example, 180 mm/sec. Then, after the tip end of paper P enters the conveying rollers 18, the conveying speed by the conveying motor 13 is switched to high speed, for example, 630 mm/sec in order to improve paper treatment work. In this case, if paper P becomes the loop L1 condition and the sensor 1 becomes transmissible, the paper P forwarding speed is switched to high speed and when the sensor S1 is shaded, it becomes low speed, and when the sensor S3 is shaded, the driving motor 7 is stopped Consequently, once the speed is switched to a low speed, the speed is not switched to a high speed unless the sensor S1 becomes transmissible. Repeating the above operations, the printing work continuously takes place. The forwarding method is not limited to the paper forwarding but can be applied similarly to the forwarding of film from the magazine. Now, the rewinding method according to the present invention is described. The rewinding method is applied, for example, to the photo-processing apparatus as shown in Fig. 1 like in the above-mentioned farwarding method. The rewinding method according to the present invention is, for example, applied to the photo-processing apparatus shown in Fig. 1. Such photo-processing apparatus is equipped with a printing part 2 for forwarding paper P from a magazine storing paper P in a form of roll and printing image information recorded on the developed film to this paper, a developing part 3 for developing the printed paper P, a drying part 4 for drying the developed paper P, and a cutting part 5 for cutting the dried paper P into a specified size for every frame. To this photo-processing apparatus, two magazines 1a, 1b are set. This is to reduce load of magazine replacement work and improve work efficiency by automatically switching to paper P of the other magazine 1b when paper P of one magazine 1a is exhausted or paper is changed to that of different width or kind. However, in the present invention, the number of magazines is not restricted to two. The magazine 1a is housed in a light-shielded casing, and paper P pulled out from the inside of magazine 1a is forwarded by a forwarding mechanism A comprising a pair of conveying rollers 6a, 6b and a driving motor 7 for rotating and driving the conveying roller 6a to be fed to the printing part 2. Next, the rewinding method according to the present invention will be described. In the present invention, the paper forwarded from the magazine is designed to be looped temporarily and then fed to the printing part. This is to reduce the forwarding speed of the driving motor 7 at the start and the stop of paper forwarding independently from other conveying motor by forming a loop. First, as shown in Fig. 1, the tip end of paper P stored in the magazine 1a is pulled out and inserted between a pair of conveying rollers 6a, 6b of the forwarding mechanism A. Then, at a low speed (for example, 250 mm/sec), paper P is allowed to pass a loop mechanism B and is fed, for example, by 100 mm after the sensor S is shaded with a loop forming amount by dead weight later described taken into account, and then the forwarding of paper P is stopped. Because paper P is forwarded at a low speed in this event, it is possible to absorb the slacking portion inside the magazine 1a and prevent abnormal noise or damage to paper, and because paper P is stopped at a low speed, inertia of paper roll (core) 8 can be lowered and slack of paper P inside the magazine 1a can be eliminated. Then, a motor 9 of the loop mechanism B is driven to rotate and move the conveying roller 10 and conveying guide 11 in the arrow C direction. This rotational movement allows paper P to form a loop LO by its dead weight. Then, a crimping solenoid 12 operates to hold paper P. Thereafter, the driving motor 7 is driven to forward paper P, allowing loop L2 to be formed until a sensor S2 is shaded. The paper P forwarding speed in this event can be designed to be high speed (for example, 650 mm/sec) because paper P is stopped at a low speed so that paper P in the magazine 1a is free from slackness. After the loop L2 is formed, the paper forwarding speed returns to a low speed, and then, conveying rollers 14, 15 are driven at a slow speed (for example, 180 mm/sec) to forward the paper P tip end to the position of conveying roller 16. To the paper thus forwarded, film image information is printed every frame in the printing part 2. Because the forwarding speed at a low speed by the forwarding mechanism A is designed to be larger than the conveying speed at a low speed by the conveying motor 13, the sensor S3 is certain to be shaded at the start of forwarding. When the sensor S3 is shaded by paper P in the form of loop, forwarding of paper P is stopped at a low speed. Then, the paper is successively conveyed with conveying rollers and the driving motor 7 is kept stopped even when the sensor 3 becomes transmissible, and when the sensor S2 becomes transmissible, forwarding of paper P is switched from stop to low speed. Till the tip end of paper P enters between conveying rollers 18 via the conveying roller 17, the forwarding accuracy must be improved for preventing slack and bulging of paper, accurately position the paper to the exposing position as well as forming punch holes with good positional accuracy. For this purpose, the paper P conveying speed by the conveying motor 13 is designed to be slower than the forwarding speed (250 mm/sec) of paper P, for example, 180 mm/sec. Then, after the tip end of paper P enters the conveying rollers 18, the conveying speed by the conveying motor 13 is switched to high speed, for example, 630 mm/sec in order to improve paper treatment work. In this case, if paper P becomes the loop L1 condition and the sensor 1 becomes transmissible, the paper P forwarding speed is switched to high speed and when the sensor S1 is shaded, it becomes low speed, and when the sensor S3 is shaded, the driving motor 7 is stopped. Consequently, once the speed is switched to a low speed, the speed is not switched to a high speed unless the sensor S1 becomes transmissible. Repeating the above operations, the printing work is continued. Next, when printing work is finished or the kind of paper is changed, an unexposed paper is rewound in the magazine. First of all, the exposed paper at the printing part 2 is sent to the cutting position D and separated from the unexposed paper P. The conveying roller 6a is rotated at a high speed in the reverse direction by the driving motor 7 of the forwarding mechanism A and the loop-form paper P is rewound in the magazine 1a. Then, when the loop L2 causes light to transmit to the sensor S2, the driving motor 7 is stopped and conveying rollers 14, 15 are rotated reversely by the conveying motor 13. When the sensor 3 is shaded, driving of conveying rollers 14, 15 is stopped, and in stead, the conveying roller 6a is rotated again at a high speed. In this way, based on the detection of sensors S2 and S3, the conveying rollers 14, 15 and conveying roller 6a are reversely rotated alternately to rewind paper P in the magazine 1a. When the sensor S becomes transmissible, the crimping solenoid 12 is turned off, the conveying rollers 14, 15 are stopped, and the conveying roller 6a is rotated at a high speed. When the sensor S5, the second detector for detecting the wait position of paper conveying, becomes transmissible as shown in Fig. 1 and Fig. 2a, the driving motor 7 is switched to a low speed. Next, as shown in Fig. 2b, when the tip end of paper P passes sensor S4, the first detector, reverse rotation drive of the driving motor 7 is stopped and brakes are applied to paper P with rollers 6a, 6b. In this event, as shown in Fig. 2c, the tip end of paper P would pass between conveyor rollers 6a and 6b by inertia of paper P inside the magazine 1a to be rewound, but the tip end of paper P does not go over conveyor rollers 6a, 6b and enter the light shielding slit 17. The tip end of paper P stops at the position of conveying rollers 6a, 6b. For conditions for stopping the paper P tip end between the sensor S4 and conveying rollers 6a, 6b, L > υ t - 1/2 α t 2 ( υ : low rewinding speed, α : deceleration by brakes, t: time) can be employed when the distance between rollers 6a, 6b and sensor S4 is designated to be L. The rewinding method according to the present invention is not limited to rewinding of paper but can be applied similarly to rewinding of film into the magazine. As described above, according to the forwarding method paper is forwarded at a low speed at the start of forwarding, and conversely it is stopped from the low-speed state when the forwarding is stopped, so that slack inside the magazine can be absorbed and at the same time, slack is not generated inside the magazine. Consequently, abnormal noise or damage to paper generated from the magazine inside is eliminated. Because a load during paper conveyance becomes constant, accuracy of paper conveying amount is improved. Further, according to the rewinding method of the present invention, speeds are set in multiplicity, for example, after rewinding at a high speed, the speed is switched to a low speed, then brakes are applied to paper to stop the paper tip end in front of the light shielding slit. Consequently, it is possible to shorten the working time by setting the speed to high speed up to the middle of rewinding, which does not contribute to production. It is also possible to reduce paper inertia because brakes are applied to stop operation by switching high speed to low speed. As a result, it is possible to improve accuracy of the paper stopping position.

Claims: A method of rewinding a photosensitive material (P) in a photo-processing apparatus (2-5) in which the photosensitive material (P) is forwarded from the magazine (1a) for storing the photosensitive material (P) wound in a form of roll for treatment, characterized by the steps of: successively providing a forwarding mechanism (A, 6a, 6b), and first and second detectors (S4, S5) for detecting a tip end of the photosensitive material (P) in front of a magazine light shielding slit; rewinding the photosensitive material (P) at a high speed by the forwarding mechanism (A, 6a, 6b) when the photosensitive material (P) forwarded from the magazine inside is rewound in the magazine (1a) until the tip end of the photosensitive material (P) is detected by the second detector (S5), and switching the speed to a low speed after the tip end passes the second detector (S5), and applying brake, when the photosensitive material (P) passes the first detector (S4), to allow the tip end to stop at a position in the forwarding mechanism (A, 6a, 6b) in front of said magazine light shielding slit.

Inventors: NARUKAMI SHINJI, NARUKAMI, SHINJI, NARUKAMI, SHINJI, C/O NORITSU KOKI CO., LTD.
Applicants: NORITSU KOKI CO LTD, NORITSU KOKI CO., LTD.
Application year: 1996
Main classification: G03B27
IPC codes: G03B27