US3836060A - Apparatus for transporting webs in photographic copying machines or the like - Google Patents

Apparatus for transporting webs in photographic copying machines or the like Download PDF

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Publication number
US3836060A
US3836060A US00326298A US32629873A US3836060A US 3836060 A US3836060 A US 3836060A US 00326298 A US00326298 A US 00326298A US 32629873 A US32629873 A US 32629873A US 3836060 A US3836060 A US 3836060A
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United States
Prior art keywords
generating device
web
friction generating
advancing rolls
back support
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US00326298A
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English (en)
Inventor
S Steinberger
A Fleck
W Englert
P Ehrengruber
W Baasner
K Dreher
M Pflugbeil
E Nagel
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Agfa Gevaert AG
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Agfa Gevaert AG
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/32—Projection printing apparatus, e.g. enlarger, copying camera
    • G03B27/52—Details
    • G03B27/58—Baseboards, masking frames, or other holders for the sensitive material
    • G03B27/587—Handling photosensitive webs

Definitions

  • ABSTRACT A photographic printing machine with a single pair of advancing rolls which are located upstream or downstream of the gate and pressure plate and are driven intermittently to place a fresh increment of a photosensitive web into register with the window of the gate prior to the making of an exposure.
  • a roller or pad consisting of or including soft rubber or similar friction generating material is located downstream or upstream of the gate opposite a back support and is moved toward the back support away from the advancing rolls in response to movement of the pressure plate to its operative position, or by a discrete actuating means, so as to tension the web between the back support and the advancing rolls not later than when the pressure plate reaches its operative position.
  • the present invention relates to apparatus for transporting webs of paper, photographic film or other flexible material, and more particularly to apparatus for stepwise transport of webs in photographic printing or copying machines or the like. Still more particularly, the invention relates to improvements in apparatus which can be utilized with advantage to place successive portions or increments of photosensitive webs into register with the gate of a photographic printing or copying machine prior to exposure of such increments to printing light.
  • the web slips relative to the upstream rolls during each stepwise transport to cause pronounced wear on the upstream rolls and to prevent accurate transport of the web by steps of identical length.
  • the diameters of all advancing rolls must be maintained within a very narrow range of tolerances and the bias of upstream rolls upon the web must be regulated with a high degree of precision. All this contributes to initial and maintenance cost of the machine.
  • An object of the invention is to provide a web transporting apparatus, particularly for use in a photographic printing or copying machine, wherein the web need not be tensioned with a substantial force during lengthwise transport.
  • Another object of the invention is to provide a web transporting apparatus which can operate properly with a single pair of advancing rolls.
  • a further object of the invention is to provide a web transporting apparatus with novel and improved means for tensioning the web upon completed stepwise transport and in such a way that the wear on the tensioning means is less pronounced than in heretofore known apparatus.
  • An additional object of the invention is to provide a web transporting apparatus wherein the stepwise transport of a web, such as a strip of paper one side of which is coated with a layer of photosensitive material, and the tensioning of the web upon completion of each stepwise transport result in generation of negligible quantities of dust.
  • Still another object of the invention is to provide a web transporting and tensioning apparatus which can automatically compensate for differences in the thickness of successive portions of a single web and/or for differences in thicknesses of successive webs.
  • a further object of the invention is to provide a web transporting and tensioning apparatus wherein the slippage of tensioning means relative to the web is less pronounced and can be controlled with a higher degree of accuracy than in conventional apparatus.
  • An ancillary object of the invention is to provide a photographic printing or copying machine which embodies the improved web transporting and tensioning apparatus.
  • the invention is embodied in an apparatus for stepwise transport of elongated webs, particularly for stepwise transport of photosensitive webs in photographic copying or printing machines.
  • the apparatus comprises a single pair of intermittently driven advancing rolls which serve to transport a web lengthwise along a predetermined path, preferably behind the window in the gate in a photographic printing machine and in front of a pressure plate which is movable between an operative position of engagement with the web behind the gate and an inoperative or retracted position, a roller, pad or an analogous friction generating device which is adjacent to one side of the path and is spaced apart from the advancing rolls so that the gate and the pressure plate are located between the friction generating device and the advancing rolls, a back support (e.g., a rigid plate-like member which may but need not be integral with the gate) adjacent to the other side of the path opposite the friction generating device, and displacing means which is actuatable (e.g., by a rotary electromagnet) to urge the friction generating device toward the
  • the displacing means may include the pressure plate and is preferably actuated shortly before or immediately after completion of each intermittent movement of the advancing rolls so that the web is properly tensioned not later than when its rear side is engaged and clamped by the pressure plate whereby the web portion which registers with the window of the gate cannot change its position during exposure of the web to printing light.
  • FIG. 1 is a fragmentary diagrammatic partly elevational and partly vertical sectional view of a photographic printing machine comprising a web transporting and tensioning apparatus which embodies one form of the invention
  • FIG. 3 is a similar fragmentary sectional view of the printing machine and a web transporting and tensioning apparatus constituting a further modification of the apparatus shown in FIG. 1;
  • FIG. 4 is a fragmentary sectional view of a printing machine and an elevational view of a fourth web transporting and tensioning apparatus;
  • FIG. 5 is a fragmentary sectional view of a printing machine and of a fifth web transporting porting and tensioning apparatus
  • FIG. 7 is a view similar to that of FIG. 5 but showing a portion of a sixth web transporting and tensioning apparatus
  • FIG. 8 is a fragmentary sectional view of a printing machine and of a seventh web transporting and tensioning apparatus.
  • FIG. 9 is a diagram of an electric circuit for the apparatus of FIG. 8.
  • FIG. 1 illustrates a portion of a photographic copying or printing machine which comprises a light source 1 located in front of a reflector 2 and behind a system of condenser lenses 3.
  • the lenses 3 are located behind a support (not shown) fora light-transmitting original 4 (e.g., a photographic negative) which is imaged by an objective lens 5 onto the photosensitive layer of an elongated web 7.
  • the latter is located behind a gate 6 having a rectangular window 6a through which the printing light passes to reach the photosensitive layer of the web 7.
  • a pressure plate 8 is mounted behind the path for the web 7 and is movable by any suitable conventional actuating mechanism (e.g...
  • an electromagnet so as to press the web 7 against the adjacent surface of the gate 6 during exposure of photosensitive material to printing light issuing from the source 1 and passing through the original 4.
  • the pressure plate 8 is lowered, as viewed in FIG. 1, prior to start of each printing or copying operation and is thereupon returned to the illustrated retracted or inoperative position so as to allow for lengthwise movement of the web 7 in a direction to the right, as viewed in FIG. 1, whereby an unexposed increment or portion of photosensitive material at the underside of the web moves into register with the window 6a.
  • a roll of fresh (unexposed) web 7 is stored on a supply reel 10 which is installed in the interior of a lighttight cassette or container 9.
  • the web 7 passes over fixed guide rollers 11, 12 in the cassette 9, thereupon over a third fixed guide roller 13, over a movably mounted loop forming roller 14, and through the nip of two advancing rolls 15, 16 which are located immediately or closely ahead of the gate 6 and at least one of which is driven intermittently to advance the web 7 in stepwise fashion.
  • the exposed web 7 is collected by the driven takeup reel 21 in a second cassette or container 22. Prior to reaching the takeup reel 21, successive increments of the web 7 must pass over a spring-biased loop forming roller 17 and three fixed guide rollers 18, 19 and 20.
  • the improved web transporting apparatus comprises a friction generating device here shown as a soft rubber pad 23a which is attached to a coupling element in the form of a leaf spring 23.
  • the latter is riveted or otherwise secured to a bracket 8a of the pressure plate 8.
  • the curvature of the leaf spring 23 is selected in such a way that the pad 23a tends to move in a direction to the right, as viewed in FIG. 1, when the pressure plate 8 is caused to move toward the rear side of that portion of the web 7 which overlies the gate 6.
  • the gate comprises a rigid plate-like extension 24 which is located opposite the pad 23a and constitutes a back support for the adjacent portion of the web 7.
  • the parts 8a and 23 constitute or form components of a displacing means which urges the pad 23a toward the back support 24 and simultaneously moves the pad 23a away from the advancing rolls 15, 16 in response to movement of the pressure plate 8 to its operative position.
  • the parts assume the positions shown in FIG. 1. It is assumed that the advancing rolls 15, 16 have completed a stepwise transport of the web 7 in the direction indicated by arrow A so that the window 6a of the gate 6 registers with an unexposed portion of the photosensitive layer at the underside of the web.
  • the web portion between the advancing rolls 15, 16 and the fixed guide roller 18 is tensioned to a certain extent by the pivotable loop forming roller 17 under the action of the spring 17a.
  • the aforementioned actuating mechanism causes the pressure plate 8 to descend and to press the web 7 against the upper side of the gate 6.
  • the leaf spring 23 undergoes deformation as soon as the pad 23a begins to bear against the rear side of the web 7 opposite the back support 24.
  • the upper surface of the back support 24 is preferably smooth so that it offers negligible resistance to sliding movement of the web 7 in the direction indicated by arrow A.
  • the friction between the rear side of the web 7 and the pad 23a is more pronounced so that the pad 23a tends to push the web 7 in a direction to the right to thereby tension that portion of the web which extends between the advancing rolls 15, 16 and the back support 24.
  • the peripheral surfaces of the rolls 15, 16 are preferably provided on a material having a high coefficient of friction so that the rolls 15, 16 pinch the web 7 with a force which suffices to prevent withdrawal of web from the cassette 9 while the pressure plate 8 moves toward its operative position. Furthermore, the conventional spring or springs which bias the advancing rolls 15, 16 toward each other are strong enough to prevent the web 7 from sliding relative to the rolls 15, 16 during deformation of the leaf spring 23, i.e., during movement of the pressure plate 8 toward the operative position.
  • the force which the pad 23a appliesto the rear side of the web 7 is used exclusively to tension the web in the region behind the gate 6 and to thus insure that the unexposed portion of the photosensitive layer which registers with the window 60 is invariably located in a predetermined plane not later than when the pressure plate 8 moves into actual clamping engagement with the rear side of the web.
  • the pad 23a begins to slip along the rear side of the web 7 as soon as the latter is properly tensioned for engagement by the pressure plate 8.
  • the loop forming roller 17 insures that the web portion between the pad 23a and the guide roller 18 remains under requisite tension during exposure of photosensitive material behind the window 6a to printing light issuing from the source 1 and passing through the original 4.
  • the pressure which the plate 8 applies against the rear side of the web 7 suffices to prevent any shifting of the web during the making of an exposure, even if the deformation of leaf spring 23 has reached and exceeds a stage during which the pad 23a subjects the web to a maximum tensioning action.
  • the apparatus of FIG. 1 is capable of transporting the web with a high degree of accuracy so that the machine including the parts shown in FIG. 1 can be used for the making of customary prints with margins at two or more sides as well as for the making of so-called marginless prints.
  • the pressure plate 8 Upon completion of an exposure, the pressure plate 8 is returned to the illustrated inoperative position whereby the leaf spring 23 reassumes its normal shape to lift the pad 23a off the rear side of the web 7 or to maintain the pad in negligible frictional engagement with the rear side of the web so that the latter can readily advance lengthwise in response to renewed rotation of the advancing rolls 15, 16 and takeup reel 21.
  • the leaf spring 23 moves the pad 23a counter to the direction indicated by arrow A; however, this need not result in any appreciable movement of the web toward the advancing rolls 15, 16 because the bias of the spring 17a can be readily selected in such a way that the loop forming roller 17 opposes the leftward movement of the web during lifting of the pressure plate.
  • the loop forming roller 17 will immediately tension or tauten the web downstream of the advancing rolls 15, 16 not later than when the pressure plate 8 returns to the inoperative position of FIG. 1 so that the advancing rolls 15, 16 can begin with the next stepwise transport of the web 7 in order to place the next unexposed portion of the photosensitive layer into register with the window 6a.
  • the pressure plate 8 thereupon descends and the pad 23a tensions the web 7 prior to making of the next exposure.
  • the leaf spring 23 can be said to constitute a onepiece springy coupling between the soft rubber pad 23a and the bracket 8a of the pressure plate 8.
  • FIG. 2 illustrates a modified coupling which constitutes a simple linkage and includes a plate-like shoe 25 for a softrubber friction generating pad 25a.
  • the linkage movably connects the pad 250 to the pressure plate 8 in such a way that the pad 25a automatically moves in the direction indicated by arrow A when the pressure plate 8 is caused to move toward its operative position.
  • the shoe 25 is articulately connected to a shank or stem 25b and is biased downwardly by a helical spring 26 which insures that the pad 25a is located close to or even abuts against the rear side of the web 7 while the pressure plate 8 dwells in the illustrated inoperative position.
  • the upper end portion of the shank 25b is reciprocable in and can swivel relative to an apertured lug 28 provided on a carrier or frame 29 which is secured to or forms an integral part of the pressure plate 8.
  • the carrier 29 is further provided with an inclined arcuate guide slot 29a for a pin 27 which is secured to the shank 25b or directly to the shoe 25.
  • FIG. 3 A further coupling between the pressure plate 8 and a friction generating pad 32a of soft rubber is shown in FIG. 3.
  • This coupling comprises a lever 30 which is pivoted to the pressure plate 8, as at 30a, and carries a pivotable shoe 32 for the pad 32a.
  • a stop pin 31 on the pressure plate 8 serves as an abutment for the lever 30 so that the latter normally assumes the illustrated in clined position when the pressure plate 8 is caused to assume the inoperative or retracted position shown in FIG. 3.
  • the back support 24 is shown as forming an integral plate-like part of the gate 6; however, it is clear that the back support 24 of FIG. 1, 2 or 3 can constitute a discrete part which need not even be fixed to the gate 6.
  • the lever 30 pivots by gravity and abuts against the stop pin 31 to thereby maintain the pad 32a out of engagement with or close to the rear side of the web 7.
  • the actuating mechanism e.g., an electromagnet
  • the lever 30 is automatically compelled to pivot in the direction indicated by arrow A (i.e., away from the advancing rolls and the window 6a) whereby the pad 32a tensions the web 7 between the advancing rolls and the back support 24.
  • the pad 32a slides relative to the rear side of the web 7, at least during the last stage of movement of the pressure plate 8 toward its operative position.
  • the friction between the preferably smooth upper surface of the back support 24 and the front side of the web 7 is much less than the friction between the pad 32a and the rear side of the web.
  • FIG. 4 illustrates a further web transporting apparatus wherein the gate 6 supports pairs of guide pins 49a, 50a and pairs of helical springs 49, 50 for a reciprocable pressure plate 108.
  • the springs 49, 50 permanently urge the pressure plate 108 to the illustrated inoperative or retracted position.
  • the advancing rolls 15, 16 are located downstream or behind the window 60, as viewed in the direction (arrow A) of stepwise movement of the web 7.
  • the gate 6 comprises an integral ex tension or back support 24 located opposite a substantially U-shaped rubber-coated friction generating device 123a provided on an elastic displacing member or holder 123 pivotably mounted in the frame of the printing machine, as at 123b.
  • That portion of the pressure plate 108 which overlies the back support 24 is provided with an opening 108b through which the friction generating device 123a extends to engage the rear side of the web 7 when the displacing member or holder 123 is caused to pivot in a counterclockwise direction, as
  • the actuating means for the displacing member 123 includes a rotary electromagnet 48 having an armature 48a which is rotated counterclockwise, as viewed in FIG. 4, when the electromagnet 48 is energized, whereby the friction generating device 123a bears against the web 7 above the back support 24 and simultaneously moves counter to the direction indicated by arrow A in response to deformation of the displacing member 123.
  • a spring 123C or the like serves to maintain the displacing member 123 in constant engagement with the roller-shaped end portion 48b of the armature 48a.
  • the end portion 4812 additionally serves to engage a projection 108a of the pressure plate 108 and to move the pressure plate to the operative position against the opposition of springs 49, 50 when the electromagnet 48 rotates its armature 48a in a counterclockwise direction.
  • the pressure plate 108 can be provided with suitable rails, walls or analogous confining means which serve to prevent lateral movements of the web 7 so that the web is held for lengthwise movement along an accurately determined path.
  • the aforementioned confining means can enter suitable recesses of the gate 6 when the pressure plate 108 descends in response to energization of the electromagnet 48.
  • the spring 1236 moves the displacing member 123 to the illustrated position whereby the displacing member holds the friction generating device 123a in a starting position of disengagement from the rear side of the web 7.
  • the path for the web 7 above the gate 6 is then totally unobstructed so that the leader of a fresh web can be readily introduced into the nip of the advancing rolls 15, 16.
  • the electromagnet 48 is energized upon completed lengthwise transport of the web 7 through a distance which is required to place a fresh increment of the photosensitive layer at the underside of the web into register with the window 6a.
  • the energization of electromagnet 48 entails a counterclockwise movement of the armature 48a whereby the end portion 48b pivots the displacing member 123 against the opposition of the spring 1236 and causes the friction generating device 123a to bear against the web 7 opposite the back support 24.
  • the point of contact between the device 123a and the web 7 moves counter to the direction indicated by arrow A (i.e., away from the window 6a and advancing rolls 15, 16) to subject the web portion between the advancing rolls and the back support 24 to requisite tension.
  • the movement of friction generating device 123a counter to the direction indicated by arrow A may coincide with or may precede the engagement of the end portion 48b with the projection 108a.
  • the movement of the pressure plate 108 to its operative position of engagement with the rear side of the web 7 may take place simultaneously with or may follow the tensioning action of the friction generating device 123a. Such tensioning action is completed not later than when the pressure plate 108 begins to bear against the rear side of the web 7.
  • the electromagnet 48 Upon completion of an exposure, the electromagnet 48 is deenergized whereby the spring 123c returns the parts 48a, 48b, 123 and 123a to the illustrated positions. At the same time, the springs 49, 50 return the pressure plate 108 to the illustrated inoperative position. The advancing rolls 15, 16 are thereupon driven through a predetermined angle to place a fresh increment of photosensitive layer on the web 7 into register with the window 60.
  • the electromagnet 48 may be energized to move the armature 48a back to the illustrated position; the apparatus is then provided with a spring which is strong enough to cause the friction generating device 123a to tension the web 7 in response to deenergization of the electromagnet.
  • the electromagnet 48 assumes a first (energized or deenergized) condition to effect a movement of the device 123a toward the back support 24 and away from the window 6a, and a second (deenergized or energized) condition to effect a movement of the device 123a back to the starting position.
  • the electromagnet 48 constitutes but one form of actuating means which can be used to cause the displacing member 123 to move the friction generating device relative to the back support 24.
  • the electromagnet 48 can be replaced by a motor, such as an electric motor. It is equally within the purview of the invention to provide first actuating means for displacing member 123 and discrete second actuating means for moving the pressure plate 108 to its operative position.
  • FIG. 5 illustrates a portion of a further apparatus wherein the displacing means for the friction generating device 34a (e.g., a soft-rubber pad) constitutes a rotary electromagnet 33 having a pivotable armature or lever 34.
  • the web is shown at 7, the gate at 6, the window at 6a and the back support at 24.
  • the advancing rolls (not shown) are assumed to be located upstream (to the left) of the window 6a so as to intermittently advance the web 7 in the direction indicated by arrow A.
  • the electromagnet 33 includes a return spring (not shown) which urges the armature 34 in a clockwise direction, as viewed in FIG.
  • the center of curvature of the arcuate friction generating device 34a is preferably located on or close to the pivot axis of the armature 34.
  • the armature 34 When the electromagnet 33 is energized, the armature 34 turns in a counterclockwise direction, as viewed in FIG. 5, and moves the friction generating device 34a to the position indicated by broken lines. During such movement, the device 340 moves into progressively stronger frictional engagement with the rear side of the web 7 and tensions the web between the advancing rolls and the back support 24 so that the web is properly tensioned not later than when its rear side is engaged by the pressure plate, not shown.
  • the circuit of the electromagnet 33 is illustrated in FIG. 6.
  • a shaft 133 which drives the advancing rolls also drives a cam 134 which completes a full revolution during a complete cycle including the lengthwise transport of web 7 by a step, the energization of electromagnet 33, the movement of pressure plate to its operative position, and deenergization of the electromagnet.
  • the circuit comprises a control switch 35 which is normally closed and can be opened by a lobe of the cam 134 when the shaft 133 begins to rotate the advancing rolls.
  • the switch 35 is in series with the winding of the electromagnet 33 and with a normally open control switch 36 which is connected in parallel with a switch 37 in the holding circuit of the electromagnet.
  • the control switch 36 is closed for a short interval of time by a second lobe of the cam 134 (or by a lobe of a second cam, not shown) upon completed stepwise transport of the web 7.
  • the cam 134 closes the control switch 36 for a short interval of time to energize the electromagnet 33 which moves the armature 34 to the broken-line position of FIG. 5 so that the friction generating device 34a tensions the web 7 by tending to move the web in the direction indicated by arrow A.
  • the pressure plate thereupon descends to assume its operative position and to press the web 7 against the rear side of the gate 6.
  • the electromagnet 33 closes the switch 37 when the armature 34 reaches the brokenline position of FIG. 5 whereby the circuit of the electromagnet remains completed regardless of the position of the control switch 36.
  • the armature 34 maintains the friction generating device 34a in the broken-line position of FIG. 5 during the making of an exposure.
  • the shaft 133 continues to rotate and causes the cam 134 to open the control switch 35 for a short interval of time upon completion of an exposure to thus deenergize the electromagnet 33 whereby the aforementioned spring returns the armature 34 and the friction generating device 34a to the solid-line positions of FIG. 5.
  • the pressure plate then returns to its inoperative position and the shaft 133 again causes the advancing rolls to transport the web 7 by a step while the electromagnet 33 remains deenergized.
  • the switch 37 opens as soon as the armature 34 leaves the broken-line position of FIG. 5.
  • FIG. 7 illustrates a modification of the apparatus shown in FIG. 5.
  • the friction generating device 38 is a roller which consists of or comprises a peripheral layer of soft rubber and is non-rotatably secured to a leaf spring 39 mounted on the armature 34 of the rotary electromagnet 33.
  • the apparatus of FIG. 7 preferably further comprises means for adjusting the initial stressing of the leaf spring 39 to thereby regulate the force with which the roller 38 tensions the web 7 when the electromagnet 33 is energized to turn the armature 34 and the spring 39 in a counterclockwise direction.
  • the leaf spring 39 can be replaced by a weaker or stronger leaf spring.
  • leaf spring 39 Another advantage of the leaf spring 39 is that it enables the roller 38 to subject the entire adjacent portion of the rear side of the web 7 to a uniform tensioning force when the electromagnet 33 is energized. Such force reaches a maximum value shortly after the armature 34 leaves the solid-line position of FIG. 7 which is desirable because the adjacent portion of the web 7 is thereby subjected to a maximum acceleration in a direction (arrow A) away from the advancing rolls (not shown and assumed to be located to the left of the window 6a).
  • the extent of counterclockwise pivotal movement of the armature 34 is preferably selected in such a way that the roller 38 moves beyond a dead-center position in which the adjacent portion of the web 7 is subjected to a maximum tensioning stress. This allows for a reduction of the force with which the electromagnet 33 must maintain the roller 38 in the broken-line second position of FIG. 7.
  • a further advantage of the leaf spring 39 is that it can compensate for eventual inaccuracies in selection of the distance between the pivot axis of the armature 34 and the back support 24 and for varying thicknesses of 5 successive webs.
  • the circuit of the electromagnet 33 of FIG. 7 is preferably identical with or similar to the circuit of FIG. 6.
  • the friction generating device is a cylindrical 1O sleeve or roller 41 consisting of soft rubber and secured for rotation to a core 40 rigid with a shaft 400 which carries a gear 42 in mesh with a driver gear 43. The latter is driven by the output shaft of an electric motor 44 (see FIG. 9).
  • the periphery of the sleeve 41 is provided with three equidistant recesses or flats 410 which alternate with convex web-engaging portions 41b.
  • the sleeve 41 has three recesses 41a and three convex portions 41b.
  • the distance between the axis of the shaft 400 and the back support 24 is selected in such a way that the convex portions 41b of the sleeve 41 can engage and tension the web 7 when the core 40 is rotated in a counterclockwise direction, as viewed in FIG. 8, so as to place a convex portion 41b into engagement with the rear side of the web 7.
  • the advancing rolls are located to the left of the window 6a.
  • the number of teeth on the gear 42 is six times the number of teeth on the driver gear 43.
  • the output shaft of the motor 44 further carries a disk-shaped cam 45 having a lobe 45a which can open a normally closed control switch 46 connected in series with the motor 44 and in parallel with a starter switch 47.
  • the starter switch 47 is normally open and is closed for a short interval of time upon completion and also prior to completion of each stepwise transport of the web 7.
  • the lobe a maintains the switch 46 in open position when the motor 44 is idle.
  • the sleeve 41 assumes the angular position of FIG. 8 prior to start of stepwise transport of the web 7 by the advancing rolls. Since the lowermost recess 41a of FIG.
  • the advancing rolls can transport the web 7 without any interference on the part of the sleeve 41.
  • the starter switch 47 is closed (for example, by one of the advancing rolls in a manner not shown in FIG. 9) to thus complete the circuit of the motor 44.
  • the motor rotates the cam 45 so that the lobe 450 allows the switch 46 to close whereby the switch 46 completes the motor circuit irrespective of the position of the starter switch 47.
  • the motor 44 also rotates the driver gear 43 which rotates the gear 42 and hence the sleeve 41 so that the latter moves the lowermost recess 41a away from the back support 24 and causes the next-following convex portion 41b to engage and tension the web 7 prior to movement of the pressure plate (not shown) to its operative position.
  • the lobe 45a again opens the switch 46 to arrest the motor 44 after the gear 43 completes a full revolution and thus causes the gear 42 to turn the sleeve 41 through 60.
  • Eventual inaccuracies in the extent of angular displacement of the gear 42 are compensated for by slippage of the sleeve 41 relative to the rear side of the web 7.
  • the starter switch 47 is closed again upon completion of an exposure whereby the motor 44 is started and causes the sleeve 41 to turn through 60 so as to move the next recess 41a opposite the back support 24. This insures that, when the advancing rolls are set in motion, the web 7 can move lengthwise (arrow A) without any interference on the part of the sleeve 41.
  • the advancing rolls 15, 16 can be located ahead of or behind the friction generating device (compare, for example, the FIGS. 1 and 4). It is further clear that the rigid plate-like stationary back support 24 can be replaced by a back support in the form of an idler roller which is rotated by the friction generating device through the intermediary of the web while the friction generating device moves in a direction away from the advancing rolls. Still further, and as already mentioned before, the electromagnet 48 or 33 can be energized to effect a movement of the friction generating device to or from its starting position.
  • the actuating means for the displacing means can be started before the transport of the web by the advancing rolls is completed, i.e., the sleeve or roller 41 of FIG. 8 can begin to rotate even before the advancing rolls are arrested. This reduces the overall time which is spent for the making of an exposure because the sleeve 41 can engage and tension the web 7 as soon as the advancing rolls come to a halt.
  • the friction generating device is in continuous contact with the rear side of the web (e.g., as shown in FIG.
  • the actuating means for the displacing means is preferably started after the advancing rolls come to a standstill. It is clear, however, that the displacing means can begin to move the friction generating device away from the advancing rolls even before the advancing rolls come to a standstill, even if the friction generating device is in continuous engagement with the web.
  • the friction generating device 23a will assist the advancing rolls 15, 16 in moving the web 7 in the direction indicated by arrow A as long as the advancing rolls rotate and thereupon begins to tension the web to complete the tensioningstep before the pressure plate 8 reaches its operative position.
  • Apparatus for stepwise transport of elongated webs particularly for stepwise transport of photosensitive webs in photographic printing or copying machines, comprising a pair of intermittently driven advancing rolls arranged to transport a web lengthwise along a predetermined path; a friction generating device adjacent to one side of said path and being spaced apart from said advancing rolls; a back support adjacent to the other side of said path opposite said friction generating device; a gate adjacent to said other side of said path and located between said advancing rolls and said friction generating device; and displacing means actuatable to urge said friction generating device toward said back support and to simultaneously move said friction generating device away from said advancing rolls whereby said friction generating device tensions the web between said advancing rolls and said back support, said displacing means comprising a pressure plate located at said one side of said path opposite said gate and being movable between an inoperative position away from and an operative position of engagement with the web portion between said pressure plate and said gate, and coupling means movably connecting said pressure plate with said
  • said gate has a window and said advancing rolls are operable to transport successive increments of the web into register with said window.
  • Apparatus as defined in claim 1 further comprising means for starting the actuation of said displacing means during the last stage of each intermittent move ment of said advancing rolls.
  • Apparatus for stepwise transport of elongated webs particularly for stepwise transport of photosensitive webs in photographic printing or copying machines, comprising a pair of intermittently driven advancing rolls arranged to transport a web lengthwise along a predetermined path; a friction generating device adjacent to one side of said path and being spaced apart from said advancing rolls; a back support adjacent to the other side of said path opposite said friction generating device; a gate adjacent to said other side of said path and located between said advancing rolls and said friction generating device; a pressure plate adjacent to said one side of said path opposite said gate, said pressure plate having an opening and being movable between an inoperative position spaced apart from and an operative position of engagement with the web portion between said advancing rolls and said friction generating device; and displacing means actuatable to urge said friction generating device toward said back support and to simultaneously move said friction generating device away from said advancing rolls whereby said friction generating device tensions the web between said advancing rolls and said back support, sai ddisplac
  • Apparatus for stepwise transport of elongated webs particularly for stepwise transport of photosensitive webs in photographic printing or copying machines, comprising a pair of intermittently driven advancing rolls arranged to transport a web lengthwise along a predetermined path; a friction generating device adjacent to one side of said path and being spaced apart from said advancing rolls; a back support adjacent to the other side of said path opposite said friction generating device; displacing means actuatable to urge said friction generating device toward said back support and to simultaneously move said friction generating device away from said advancing rolls whereby said friction generating device tensions the web between said advancing rolls and said back support, said displacing means comprising electromagnet means including an armature and having an energized condition and a deenergized condition, said friction generating device being mounted on said armature; first control means for causing said electromagnet means to assume one of said conditions upon completion of intermittent movement of said advancing rolls whereby said armature moves said friction generating device from a starting position toward a second
  • said electromagnet means comprises a rotary electromagnet and said armature includes a lever which is pivotable in response to a change in the condition of said electromagnet means to thereby move said friction generating device in a direction away from said advancing rolls.
  • Apparatus for stepwise transport of elongated webs particularly for stepwise transport of photosensitive webs in photographic printing or copying machines, comprising a pair of intermittently driven advancing rolls arranged to transport a web lengthwise along a predetermined path; a friction generating device adjacent to one side of said path and being spaced apart from said advancing rolls; a back support adjacent to the other side of said path opposite said friction generating device; displacing means actuatable to urge said friction generating device toward said back support and to simultaneously move said friction generating device away from said advancing rolls whereby said friction generating'device tensions the web between said advancing rolls and said back support, said displacing means comprising electromagnet means including an armature, said friction generating device being mounted on said armature and said displacing means further comprising resilient means connecting said friction generating device to said armature, said friction generating device being movable beyond a dead-center position in response to completed actuation of said displacing means to move said friction generating device
  • Apparatus for stepwise transport of elongated webs comprising a pair of intermittently driven advancing rolls arranged to transport a web lengthwise along a predetermined path; a friction generating device adjacent to one side of said path and being spaced apart from said advancing rolls, said friction generating device comprising a roller which is rotatable about its axis and consists at least in part of a material having a high coefficient of friction, said roller having at least one recessed portion and at least one second portion; a back support adjacent to the other side of said path opposite said friction generating device; and displacing means actuatable to urge said friction generating device toward said back support and to simultaneously move said friction generating device away from said advancing rolls whereby said friction generating device tensions the web between said advancing rolls and said back support, said displacing means comprising means for rotating said roller of said friction generating device between a first position in which said recessed portion of said roller is adjacent to

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Projection-Type Copiers In General (AREA)
  • Advancing Webs (AREA)
  • Delivering By Means Of Belts And Rollers (AREA)
  • Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
US00326298A 1972-01-26 1973-01-24 Apparatus for transporting webs in photographic copying machines or the like Expired - Lifetime US3836060A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2203479A DE2203479B2 (de) 1972-01-26 1972-01-26 Fotografisches Kopiergerät

Publications (1)

Publication Number Publication Date
US3836060A true US3836060A (en) 1974-09-17

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ID=5834006

Family Applications (1)

Application Number Title Priority Date Filing Date
US00326298A Expired - Lifetime US3836060A (en) 1972-01-26 1973-01-24 Apparatus for transporting webs in photographic copying machines or the like

Country Status (6)

Country Link
US (1) US3836060A (ja)
JP (1) JPS5232573B2 (ja)
CH (1) CH549228A (ja)
DE (1) DE2203479B2 (ja)
GB (1) GB1396243A (ja)
IT (1) IT978315B (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4015763A (en) * 1974-09-30 1977-04-05 The Jade Corporation Alignment pawl for film-carrier advance mechanism
US4106324A (en) * 1974-11-16 1978-08-15 Erich Grau Stanzwerk Fur Elektrobleche Feeding mechanism
US20050140963A1 (en) * 2003-07-11 2005-06-30 Baker Hughes, Incorporated Continuous paper feed system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51115825A (en) * 1975-04-03 1976-10-12 Dainippon Screen Mfg Co Ltd Exposure device for belt-shaped photosensitive material

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2948177A (en) * 1956-05-29 1960-08-09 Miller Wrapping & Sealing Mach Web cutting mechanism
US3460158A (en) * 1967-10-25 1969-08-05 Bausch & Lomb Recorder with chart tensioning means

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2948177A (en) * 1956-05-29 1960-08-09 Miller Wrapping & Sealing Mach Web cutting mechanism
US3460158A (en) * 1967-10-25 1969-08-05 Bausch & Lomb Recorder with chart tensioning means

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4015763A (en) * 1974-09-30 1977-04-05 The Jade Corporation Alignment pawl for film-carrier advance mechanism
US4106324A (en) * 1974-11-16 1978-08-15 Erich Grau Stanzwerk Fur Elektrobleche Feeding mechanism
US20050140963A1 (en) * 2003-07-11 2005-06-30 Baker Hughes, Incorporated Continuous paper feed system
US7295289B2 (en) * 2003-07-11 2007-11-13 Baker Hughes Incorporated Continuous paper feed system

Also Published As

Publication number Publication date
GB1396243A (en) 1975-06-04
DE2203479A1 (de) 1973-08-02
IT978315B (it) 1974-09-20
JPS4887836A (ja) 1973-11-17
JPS5232573B2 (ja) 1977-08-23
DE2203479C3 (ja) 1976-01-08
CH549228A (de) 1974-05-15
DE2203479B2 (de) 1975-05-15

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