METHOD AND APPARATUS FOR CORRECTING SNAKING IN A ROLLFILM FEEDING APPARATUS

Abstract: An apparatus for correcting snaking of rollfilm comprises a driving roller (11) for feeding the rollfilm to the exposure position with the film being maintained flat, pinch rollers (12, 12′) provided such that they can approach or be separated from said driving roller (11), switching means for switching between the abutment and separation of said pinch rollers (12, 12′) and said driving roller (11), and cutting means (22, 23) for cutting said rollfilm.

Description: The present invention relates to an image recording apparatus with the features of claim 1. An image recording apparatus comprising feeding means and retractable headrollers for feeding the rollfilm to the exposure position is already shown in US-A-4 621 535. In such an apparatus the film intends to deviate from the longitudinal direction, which deviation is accumulated in proportion to the lenght of the rollfilm. It is the object of the present invention to provide an apparatus in which the transversal movement of said rollfilm in the width direction is not accumulated. The above described object of the present invention is attained by the features of the second part of claim 1. An advantageous embodiment of the invention is subject matter of claim 2. The invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which Fig. 1 is a cross-sectional side view showing one embodiment of the present invention, Fig. 2 is a front view of the main portion of the apparatus shown in Fig. 1, and Fig. 3 is a cross-sectionl side view showing the other operation of the apparatus shownin Fig. 1. Referring to Fig. 1, the driving roller (11) is pivoted at that position where the film surface wounded on the outer circumference thereof coincides with the exposure surface of the said light beam. A rollfilm (F) is fed between the driving roller (11) and a pair of nip rollers (12) and (12') from above and is travelled, as shown by the chained line. An upper end portion of a lever (14) is attached to a supporting shaft (13) which is erected on an appropriate portion of the frame of the exposure portion (not shown). An axis (15) is provided at the middle portion of the lever (14). A pair of nip rollers (12) and (12') are rotatably supported by a swinging plate (16) attached to the said axis (15). A spring (17) is engaged with the lower portion of the lever (14) so that the nip rollers (12) and (12') are energized to be in pressure contact with the driving roller (11). An arm (18) projecting to the driving roller is provided in the upper portion of the lever (14). A pin (19) which is erected on the arm (18) is engaged with an appropriate portion of the guide plate (21) which is attached to an axis (20). As a result, the guide plate (21) is inclined in association with the rotation of the lever (14). This guide plate (21) is provided to ensure that the tip end of the rollfilm is fed between the driving roller (11) and the upper nip roller (12) at the time of rolling the rollfilm. The function of the guide plate will be described in the following. A cutter apparatus for cutting the rollfilm in the width direction is provided below the driving roller (11). This apparatus comprises a fixed blade (22) and a rotary blade (23) provided in parallel to the rollers. The rotary blade (23) is rotated in the clockwise direction in Fig. 1 by a rotary axis (24), with the rollfilm interposed between the rotary blade (24) and fixed blade (22) is cut. An eccentric cam (25) is fitted and fixed to the rotary axis (24). The lower end portion of the lever (14) is pressed synchronized with the rotation of the rotary blade (23), and the nip rollers (12) and (12') are separated from the driving roller (11). The lever (14), swinging plate (16), spring (17), pin (19) and the eccentric cam (25) are provided at each of both ends of the nip rollers (12) and (12'). Each set is provided symmetrically. One end of the rotary axis (24) of the cutter apparatus extends out of the eccentric cam (25) as shown in Fig. 2, and a gear (26) is attached thereto. The engaging gear (27) is rotatingly driven in the counterclockwise direction in Fig. 1 by a driving apparatus (28) comprising a suitable motor, decelerating apparatus and so on. A cam (29) activating two switches (SW₁) and (SW₂) for positioning is attached to the same axis as with the gear (27). Each of the switches is activated when it is engaged with the concave of the cam (29). Namely, in the situation of Fig. 1, the switch (SW₁) is activated. In the situation of Fig. 3, in which the cam (29) is rotated by about 225° in the counterclockwise direction, the switch (SW₂) is activated. The function of the apparatus in accordance with the illustrated embodiment will be hereinafter described. In the scanning exposure, the function is as shown in Fig. 1, namely, the eccentric cam (25) is separated from the lever (14) and the pair of nip rollers (12) and (12') nip the rollfilm (F) with pressure on the outer circumference of the driving roller (11). The driving roller is driven by a constant peripheral speed defined corresponding to the feeding speed of the rollfilm (F) and the film (F) is fed. At the same time, the rollfilm (F) is scanned and exposed spirally by the light beam. The exposed rollfilm is fed out in the tangential direction at the contact portion of the lower nip roller (12') and the driving roller (11), as shown in the chained line (F'). The rollfilm is fed through two blades (22) and (23) of the cutter apparatus. On this occasion, if the driving roller (11) has some error in its form or if the contact pressure of the nip roller (12) or (12') against the driving roller is uneven, then the rollfilm snakes. The amount of deviation is small for the feeding of a length corresponding to one picture plane and the recorded image is not badly influenced. However, if a bias in width direction is generated on the rollfilm at the position of the driving roller (11), an inner stress or elastic deformation is caused in the film web from the supply reel to the driving roller (11). After the exposure of all the desired image regions is completed, the driving roller (11) is driven to feed the rollfilm (F) until the rear end portion of the image or the rear end portion of the necessary margin passes through the cutting position of the cutter apparatus. Thereafter, the driving roller (11) is stopped and the driving apparatus (28) is energized to activate the cutter apparatus. The rotary blade (23) is rotated through the gears (27) and (26) and the rollfilm (F) interposed between the rotary blade (23) and the fixed blade (22) is cut. The cut film is carried to an exposed film withdrawing magazine or to the developing device of the succeeding stage by a feeding apparatus, not shown. Simultaneously with the film cutting by the cutter apparatus, the eccentric cam (25) attached to the rotary axis (24) is rotated. The cam (25) presses the lower end of the lever (14) against the spring (17). As a result, the pair of nip rollers (12) and (12') are separated from the driving roller (11). Consequently, the rollfilm (F) is released from the grip between the nip rollers (12) and (12') and the driving roller (11). Therefore, even if there is a bias in the width direction, the rollfilm (F) automatically returns by the inner stress or elasticity of the rollfilm itself to the neutral position where the film should originally occupy. In the position shown in Fig. 3, where the rotary axis (24) and cam (29) are rotated by about 225°, the switch (SW₂) engages with the concave of the cam (29) to stop the driving apparatus (28). In the rest time when the exposure is not carried out, the apparatus is kept in this state. Namely, if the nip rollers (12) and (12') are kept in contact with the driving roller (11) in the rest time, the roller can possibly be deformed. Therefore, in the rest time, nip rollers are separated from the driving roller. When the operation is started again, the driving apparatus (28) is activated at the same time as or before the start of feeding by the driving roller (11). The rotary axis (24) and the cam (29) are rotated by about 135° to be in the state of Fig. 1. Meanwhile, the guide plate (21) arranged above the driving roller (11) is inclined as shown in Figs. 1 and 3 in association with the movement of the nip rollers (12) and (12'). In the state of Fig. 1, in which the nip rollers (12) and (12') are in contact pressure with the driving roller (11), the guide plate (21) is slightly separated from the path in which the rollfilm is fed. In the state of Fig. 3, in which the nip rollers (12) and (12') are separated from the driving roller (11), the guide plate is inclined to the tangential direction of the driving roller (11). The positions of the axis (20) and the pin (19) being erected on the lever (14) are selected such that the guide plate (21) performs the above described operation. This guide plate (21) is not directly connected to the feeding and adjustment of snaking of the rollfilm as described above. It is used for easily guiding the tip end of the film to the circumference of the driving roller (11) when a new rollfilm is loaded in the apparatus. Namely, it is used when a preceding rollfilm is consumed and a new rollfilm is loaded, whereby the tip end of the rollfilm is easily introduced between the driving roller (11) and the pair of nip rollers (12) and (12'). Since the tip end of the rollfilm is fed along the surface of the guide plate (21) which is aligned with the tangential direction of the driving roller (11), the new rollfilm can be easily loaded. Meanwhile, if the guide plate (21) is fixed at the position which is aligned with the tangential direction of the driving roller (11), the following problem occurs. Namely, in feeding the rollfilm by the driving roller (11) during scanning exposure, the film is in sliding contact with the surface of the guide plate (21), increasing the friction resistance. Consequently, the feeding speed may possibly become uneven. Therefore, when the nip rollers (12) and (12') are in pressure contact with the driving roller (11), the guide plate (21) is retracted from the path of the rollfilm to eliminate undesirable friction. The present invention has been described with reference to the illustrated embodiment. However, the present invention is not limited to the above described embodiment and various modifications can be made. For example, in the above embodiment, the spiral scanning type image recording apparatus is employed. In the spiral scanning type image recording apparatus, the light beam which is biased and is directed in the main scanning direction is modulated by image signals whereby the reproduction images are recorded. However, the apparatus for correcting snaking according to the present invention may be applied to an intermittent scanning type image recording apparatus. In the intermittent scanning type image recording apparatus, images on the linear regions are projected on the rollfilm through slits, whereby the reproduction images are recorded. In addition, the present invention can be applied to the apparatus other than scanning exposure type, namely, it can be applied to the apparatus such as reproduction cameras in which the whole picture in one image plane is recorded by the entire exposure at one time. In this case, driving roller and nip rollers are respectively arranged before and after the exposure position so that the rollfilm is held at the exposure position and fed. In this case, the snaking of the rollfilm can be adjusted by the same means.

Claims: An image recording apparatus comprising a driving roller (11) propelling the rollfilm (F), two pinch rollers (12, 12') extending in the axial direction of said driving roller (11) parallel and spaced apart from each other and capable of abutting on and being separated from said driving roller (11) and gripping said rollfilm (F) at least at a portion thereof where and when the pinch rollers (12, 12') abut on the driving roller (11) characterized by cutting means (22, 23) situated below said driving roller (11) for cutting said film in its width direction, swing levers (14) provided on both ends of the axis supporting said pinch rollers (12, 12'), and releasing means actuating said swing lever (14) for separating the pinch rollers from said driving roller (11), wherein said releasing means are activated after said rollfilm (F) is cut. An apparatus according to claim 1, characterized in that the cutting means comprises a fixed blade (22) and a rotary blade (23) rotated by a rotary axis (24) : and which engages with said fixed blade, and said releasing means comprises an excentric cam (25) fitted and fixed to the rotary axis (24) of the cutting means which excentric cam (25) actuates the levers (14).

Inventors: KAWAI, KENJI, OHTORII, MASAKAZU, UEYAMA, TSUTOMU, YOSHIDA, TAKUMI
Applicants: DAINIPPON SCREEN MFG. CO., LTD.
Application year: 1987
Main classification: G03B27
IPC codes: B65H23, G03B27, G03B1