Process camera

Abstract: A copyboard (11) and a platen (20) are disposed horizontally so that a copy can be horizontally placed on the copyboard (11) and a photosensitive medium can be horizontally supported on the platen. A mirror (14) disposed above the copyboard and a movable mirror (18) disposed above the platen (20) jointly form an optical path extending from the copyboard to the platen, while shortening the distance between the copyboard and the platen. Two pairs of mask plates (48) are disposed in front of and parallel to the surface of the platen (20) on which the photosensitive medium is to be supported, the mask plates being independently movable along two axes perpendicular to each other. The distances from the optical axis to the mask plates are determined for each of images to be photographed on the photosensitive medium, based on various input data including a photographing dimension, the distances between the photosensitive medium and the mask plates, etc.

Description: BACKGROUND OF THE INVENTION The present invention relates to a process camera which is easy to handle, is compact so that it only takes up a small space, and can be used in a fully bright environment, and more particularly to a process camera suitable for imposing multiple-page copy images on a large photosensitive medium for platemaking. Various process cameras for imposing copy images made up of many pages are known from U.S. Patents Nos. 3,998,546, 3,837,742, and 3,920,333, for example. According to the disclosed process cameras, a copyboard for holding a copy to be photographed and a platen for supporting a photosensitive medium are vertically disposed in confronting relation. When a copy and a photosensitive medium are to be placed on the copyboard and the platen, respectively, the copy and the photosensitive medium must be held vertically and attached to the copyboard and the platen which extend vertically. Therefore, it is troublesome to handle the copy and the photosensitive medium when they are to be set on the copyboard and the platen. In order to maintain a desired optical path length from the copyboard to the platen, it is necessary to keep the copyboard and the platen spaced from each other by a certain long distance. With the copyboard and the platen being thus spaced widely from each other, the entire process camera is long and takes up a large installation space. Japanese Utility Model Application No. 62(1987)-93665 filed by the applicant of the present application discloses a process camera which employs a mirror to bend an optical path. The mirror allows the image of a copy on a horizontal copyboard to be projected onto a photosensitive medium on a vertical platen. Therefore, the copy can easily be handled when it is attached to the copyboard. Another advantage is that the overall length of the camera is relatively small as the optical path is bent by the mirror. In each of the conventional process cameras described above, however, since at least the platen is placed vertically, a photosensitive medium should be handled with the aid of a highly reliable suction device so that the photosensitive medium will not fall off the platen. Accordingly, it is still troublesome and inconvenient to handle the photosensitive medium at the time it is to be attached to the platen. The process cameras are considerably long, and much remains to be improved to make them more compact. The process camera proposed by the applicant employs a lens and a single mirror, and lends itself to the production of a direct press plate because they can produce a positive image. If a photosensitive medium produces a negative image, however, the negative image must be converted to a reversed image. To this end, there is used a process camera in which a copy and a photosensitive medium are vertically disposed in confronting relation to each other with a focusing lens interposed therebetween, as disclosed in the U.S. Patents referred to above. The process cameras disclosed in the above U.S. Patents do not have any means for confirming the position of the copy, and suffer difficulty in positioning the copy. Stated otherwise, since there is no means for confirming the position of the copy, the copy and the photosensitive medium are vertically arranged in confronting relation to each other to facilitate the positioning of the copy. It is an object of the present invention to provide a process camera which allows a copyboard and a platen to be horizontally placed so that a copy and a photosensitive medium can easily be handled, and which permits the copyboard and the platen to be positioned closely to each other so that the process camera can be rendered compact in size. According to the present invention, there is provided a process camera comprising a horizontal copyboard for supporting an original to be copied; a horizontal platen for supporting a photosensitive member, the platen being horizontally movable for the exposure of a selected area of the photosensitive member; a mask plate assembly positioned above said horizontal platen to provide an aperture for the exposure of the selected area of the photosensitive member; a focusing lens defining an optical path, for forming an image of the original; a first mirror disposed in the optical path and above said horizontal copyboard for redirecting light from said copyboard to said focusing lens; a second mirror disposed above said horizontal platen and movable into and out of the optical path between said focusing lens and said horizontal platen, said second mirror redirecting the light from said focusing lens towards said horizontal platen, so that the image of the original is formed on said horizontal platen, when said second mirror is moved into the optical path; an index plate positioned in the optical path such that the image of the original is formed thereon, when said second mirror is moved out of the optical path; and said focusing lens being further arranged to form an image of the index plate onto said copyboard, when said second mirror is moved out of the optical path. An optical path extending from the mirror disposed above the copyboard through the focusing lens and the second mirror to said index plate is inclined such that said first mirror above said copy board is positioned higher than said second mirror. With the above arrangement, since the image of a copy placed on the horizontal copyboard is focused on a photosensitive medium on the platen through the two mirrors, the platen is placed horizontally. Therefore, the copy and the photosensitive medium can be handed more easily than in a conventional process camera in which the copyboard and the platen are vertically disposed. Because the two mirrors are used, the optical path from the copy board to the platen is directed upwardly, horizontally and then downwardly. Consequently, in order to achieve a certain optical path length, the horizontal dimensions of the process camera can be reduced to make the process camera more compact in size. The user of the two mirrors can meet the need to reverse the image of a copy and photograph the reversed image on the photosensitive medium in the same manner as when no mirror is used. If the optical path is inclined such that the first mirror above the copyboard is higher in position, than the distance between the copyboard and the first mirror above the copyboard can be increased, and the mirror can be positioned near the focusing lens where the optical path is constricted. As a result, the first mirror can be made smaller and can be manufactured with ease and high accuracy. The copyboard and the platen can be positioned closely so as to partly overlap each other while maintaining the required optical path length. The process camera is thus rendered compact in size. The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way illustrative example. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side elevation view of a process camera according to an embodiment of the present invention; Fig. 2 is a side elevation view of a process camera according to another embodiment of the present invention; and Fig. 3 is a front elevation view of the process camera shown in fig. 2; and Fig. 4 is a plan view of the process camera shown in fig. 2. DETAILED DESCRIPTION As shown in Fig. 1, a process camera according to the present invention has a copyboard 11 for placing a copy on a horizontal surface thereof, the copyboard 11 being mounted horizontally on an outer wall surface of a camera housing 52. A copy placed on the copyboard 11 may be held in position under a vacuum by a copy suction device (not shown). A light source (not shown) for illuminating a copy on the copyboard 11 is disposed obliquely upwardly of the copyboard 11. A first mirror 14 for directing light reflected from a copy on the copyboard 11 to travel horizontally is disposed above the copyboard 11 and inclined at an angle of 45 degrees with respect to the horizontal direction. The first mirror 14 is supported by a mirror holder 34 which is threaded over a horizontal feed screw 36. The mirror holder 34 is horizontally movable along a suitable guide (not shown) by the feed screw 36, but is kept nonrotatable around the feed screw 36 by the guide. The feed screw 36 is rotatable about its own axis by a stepping motor or the like (not shown). A focusing lens 16, a movable second mirror 18, and an index plate 24, which are arranged in the order named, are disposed on the optical path along which light reflected from the copyboard 11 and directed by the first mirror 14 travels. The focusing lens 16 is supported by a lens holder 38 which is threaded over a horizontal feed screw 40. The lens holder 38 has a shutter (not shown) for selectively opening and closing the optical path through the focusing lens 16. The lens holder 38 is horizontally movable along a suitable guide (not shown) by the feed screw 40, but is kept nonrotatable around the feed screw 40 by the guide. The feed screw 40 is rotatable about its own axis by a stepping motor or the like (not shown). A platen 20 is horizontally disposed in the camera housing 52. A relatively large photosensitive medium can be positioned in place on a horizontal surface of the horizontal platen 20 by a copy suction device (not shown). The horizontal platen 20 can be moved in one horizontal plane in X and Y directions by a XY feed 46. The XY feeder 46 includes crossing feed screws which are rotatable by respective stepping motors (not shown) that are independently energizable to move th horizontal platen 20 in the X and Y directions. A mask plate 48 is positioned immediately in front of, i.e., above, the surface of the horizontal platen 20 which holds a photosensitive medium thereon. The mask plate 48 may comprise an opening that defines a desired area. Near the horizontal platen 20, there are disposed a feed device (not shown) for feeding a photosensitive medium onto the horizontal platen 20, and another feed device (not shown) for feeding an exposed photosensitive medium from the horizontal platen 20 into an image developing machine (not shown). The above second mirror 18 is rotatable about a shaft 44 between an elevated position (indicated by the solid lines) in which the movable second mirror 18 is angularly lifted and inclined at 45 degrees to the optical axis of the focusing lens 16 and a lowered position (indicated by the chained lines 18A) in which the movable second mirror 18 is angularly retracted downwardly out of the optical path through the focusing lens 16. When the movable second mirror 18 is in the elevated position, it bends the optical axis of the focusing lens 16 at a right angle toward the horizontal platen 20. When the movable second mirror 18 is in the lowered position, the optical axis of the focusing lens 16 is directed toward the index plate 24 which lies vertically. The index plate 24 is positioned in conjugate relation to the upper surface of the horizontal platen 20 with respect to the movable second mirror 18. The index plate 24 is marked with two central lines extending in the X and Y directions and crossing perpendicularly to each other. The index plate 24 can be covered with an illuminating box 30. The illuminating box 30 can open and close its area corresponding to the index plate 24 by rotating such area about an appropriate shaft. The illuminating box 30 houses therein a light source (not shown) for illuminating the index plate 24. When the movable second mirror 18 is in the elevated position, there is established a focusing optical system for focusing the image of a copy on the copyboard 11 onto the horizontal platen 20. When the movable second mirror 18 is in the lowered position, there is established a focusing optical system for focusing the image of a copy on the copyboard 11 onto the index plate 24 with the light source associated with the copyboard 11 being turned on and the light source associated with the index plate 24 being turned off. When the light source associated with the copyboard 11 is turned off and the light source associated with the index plate 24 is turned on, there is established a projecting optical system for projecting the image of the index plate 24 onto the copyboard 11. Operation of the process camera thus constructed will be described below. The movable second mirror 18 is retracted into the owered position 18A, a copy is placed on the copyboard 11. When the light source associated with the copyboard 11 is turned on, the image of the copy is focused by the first mirror 14 and the focusing lens 16 onto the index plate 24. The operator can observe how the image of the copy is focused onto the index plate 24 by opening the area of the illuminating box 30 which corresponds to the index plate 24. The copy on the copyboard 11 can be moved over and positioned in place by the operator so that central marks on the copy in the X and Y directions will be aligned with the crossing central lines marked on the index plate 24. After the copy has been positioned on the copyboard 11, a marking tape or the like is applied to the index plate 24 along the outer edges of a text containing characters or the like of the copy image focused on the index plate 24. At least one tape mark is sufficient in each of the X and Y directions. Then, the first image of the copy which has been positioned is photographed on a photosensitive medium mounted on the horizontal platen 20. More specifically, the shutter on the lens holder 38 for the focusing lens 16 is closed, the movable mirror 18 is lifted into the elevated position, and the shutter is opened for given seconds and then closed again. The horizontal platen 20 has been positioned in the X and Y directions so that the image of the copy is photographed on the photosensitive medium in a predetermined position. To photograph a next copy, the light source associated with the copyboard 11 is turned off, the movable second mirror 18 is retracted into the lowered position, the area of the illuminating box 30 corresponding to the index plate 24 is closed, and the light source associated with the index plate 24 is turned on to project the image of the index plate 24 onto the copyboard 11 through the focusing lens 16 and the first mirror 14. Therefore, the crossing central lines marked on the index plate 24 and the tape marks applied thereto are projected onto the copyboard 11. Thereafter, a next copy is placed on the copyboard 11 and positioned so that the outer edges of the next of the copy are aligned with the projected tape marks. The copy may be positioned by bringing the central marks of the copy in the X and Y directions into alignment with the crossing central lines projected onto the copyboard 11. However, it is necessary to position the copy with respect to four locations, i.e., left, right, front, and rear locations, according to such a positioning process. Using the tape marks, the operator can quickly position the copy since the copy only needs to be positioned with respect to two locations. After the completion of the positioning of the copy, the image of the copy is photographed on the photosensitive medium on the horizontal platen 20 according to the aforesaid procedure. The above process is repeated to photograph the images of a number of copies successively on the photosensitive medium. Each time the image of one copy has been photographed, the horizontal platen 20 is moved over given intervals by the XY feeder 46 so that the images of many copies can be successively photographed on the single photosensitive medium. The first mirror 14 is horizontally movable by the feed screw 36 to vary the distance between the copyboard 11 and the focusing lens 16 for thereby varying the magnification. The focusing lens 16 is also horizontally movable by the feed screw 40 to correct a defocused condition caused by a change in the magnification and also make general focusing adjustments. With the embodiment described above, since the image of a copy of the horizontal copyboard 11 is focused onto a photosensitive medium on the horizontal platen 20 through the two mirrors 14, 18, the horizontal plate 20 is also placed horizontally. As a result, the copy and the photosensitive medium can be handled more easily than in the conventional process cameras in which the copyboard and the platen are vertically arranged. Furthermore, the optical path from the copyboard 11 to the horizontal platen 20 is directed upwardly, horizontally, and downwardly by the two mirrors 14, 18. Therefore, a certain required optical path length can be obtained even if the camera has reduced horizontal dimensions and is hence compact in size. While the use of two mirrors is not novel itself in other fileds of art, the two mirrors can meet requirements for reversing a copy image and photographing it on a photosensitive medium in the same manner as when no mirror is used. In addition, a copy on the copyboard 11 can be positioned with respect to the image of the index plate 24 which is projected onto the copyboard 11. Since it is not necessary to define positioning holes or notches in a copy in advance, the process of manufacturing press plates is simplified. The stepping motors of the process camera may be controlled by a computer or a similar control circuit such that the entire sequence of steps, including setting a photosensitive medium on the horizontal platen 20, photographing the images of a number of copies on the photosensitive medium in successive positions thereon, a feeding the exposed photosensitive medium to the image developing machine, can fully automatically be carried out in a bright environment under the direction of a single operator. In this connection, the process cameras disclosed in the prior U.S. Patents referred to above are operated manually almost entirely, and require photosensitive mediums to be handled in the dark room. Therefore, the earlier process cameras are inefficient to operate and require skilled manual labor to get operated on. A process camera according to another embodiment of the present invention will be described with reference to figs. 2 through 4. As shown in figs. 2 through 4, a copyboard 111 is partly embedded in an upper end portion of a camera housing 152 and lies horizontally for placing a copy on its horizontal surface. As shown in fig. 4, a pair of light sources 112 for illuminating a copy placed on the copyboard 111 is disposed obliquely upwardly of the copyboard 111. A first mirror 114 for bending laterally light reflected from a copy on the copyboard 111 is obliquely positioned above the copyboard 111. The mirror 114 is supported by a mirror holder 134 which is threaded over a feed screw 136. The mirror holder 134 is horizontally movable along a suitable guide (not shown) by the feed screw 136, but is kept nonrotatable around the feed screw 136 by the guide. The feed screw 136 is rotatable about its own axis by stepping motor or the like (not shown). A focusing lens 116, a movable second mirror 118, and an index plate 124, which are arranged in the order named, are disposed on the optical path along which light reflected from the copyboard 111 and directed by the first mirror 114 travels. The focusing lens 116 is supported by a lens holder 138 which is threaded over a feed screw 140. The lens holder 138 has a shutter (not shown) for selectively opening and closing the optical path through the focusing lens 116. The lens holder 138 is movable along a suitable guide (not shown) by the feed screw 140, but is kept nonrotatable around the feed screw 140 by the guide. The feed screw 140 is rotatable about its own axis by a stepping motor or the like (not shown). A platen 120 is horizontally disposed in the camera housing 152. The platen 120 can be moved in one horizontal plane in X and Y directions by an XY feeder 146. The XY feeder 146 includes crossing feed screws which are rotatable by respective stepping motors (not shown) that are independently energizable to move the platen 120 in the X and Y directions. Near the platen 120, there are disposed a feed device (not shown) for cutting a rolled photosensitive medium into a sheet-like photosensitive medium and feeding the photosensitive medium onto the platen 120, and another feed device (not shown) for feeding an exposed photosensitive medium from the platen 120 into an image developing machine (not shown). The movable second mirror 118 is rotatable about a shaft between an elevated position (indicated by the solid linses in fig. 2) in which the movable second mirror 118 is angularly lifted to bend the optical axis of the focusing lens 116 downwardly and a lowered position (indicated by the chained lines 118A) in which the movable second mirror 118 is angularly retracted downwardly out of the optical path through the focusing lens 116. When the movable second mirror 118 is in the elevated position, it bends the optical axis of the focusing lens 116 at a right angle toward the platen 120. When the movable second mirror 118 is in the lowered position, the optical axis of the focusing lens 116 is directed toward the index plate 124. The index plate 124 is positioned in conjugate relation to the upper surface of the platen 120 with respect to the movable second mirror 118. The index plate 124 is marked with two central lines 132 extending in the X and Y directions and crossing perpendicularly to each other, as shown in fig. 3. The index plate 124 can be covered with an illuminating box 130. The illuminating box 130 can open and close its area corresponding to the index plate 124 by rotating such area about an appropriate shaft. The illuminating box 130 houses therein a light source 128 for illuminating the index plate 124, and a mirror 126 for reflecting illuminating light from the light source 128 toward the index plate 124. The process camera shown in figs. 2 through 4 differs from the process camera shown in fig. 1 in that the feed screws 136, 140 are inclined in angle Θ to the horizontal direction so that the first mirror 114 above the copyboard 111 is positioned higher than the second mirror 118 above the platen 120, and the optical axis of the focusing lens 116 is inclined the angle Θ to the horizontal direction so that it extends parallel to the feed screws 136, 140. The first mirror 114 and the movable second mirror 118 are inclined at such an angle that the central optical axis extending from the copyboard 111 to the first mirror 114 and the central optical axis extending from the platen 120 to the second mirror 118 lie perpendicularly to the horizontal direction. When the movable second mirror 118 is in the elevated position, there is established a focusing optical system for focusing the image of a copy on the copyboard 111 onto the platen 120. When the movable second mirror 118 is in the lowered position, there is established a focusing optical system for focusing the image of a copy on the copyboard 111 onto the index plate 124 with the light sources 112 being turned on and the light source 128 being turned off. When the light sources 112 are turned off and the light source 128 is turned on, there is established a projecting optical system for projecting the image of the index plate 124 onto the copyboard 111. As illustrated in fig. 3, the platen 120 is horizontally movable from a substantially central position, indicated by the solid lines, to one at a time of positions, indicated by the chained lines 120A, in which the platen 120 can receive a photosensitive medium F from a film cartridge 156 and can deliver a photographed photosensitive medium F to an image developing machine 182. The platen 120 is also movable in X and Y directions within the housing 152 so that the images of copies can successively photographed on the photosensitive medium F in successive positions thereon. The copyboard 111 and the platen 120 are positioned closely to each other such that when the platen 120 is moved to a corner of the housing 152, the platen 120 reaches a position below a portion of the copyboard 111. The copyboard 111 and the platen 120 can be positioned closely to each other because the optical path is inclined to elevate the first mirror 114 higher than the movable second mirror 118, thus making the actual optical path longer than the horizontal distance between the mirrors 114, 118, and also because the first mirror 114 is located at a higher position to maintain the required optical path length between the copyboard 111 and the first mirror 114, thereby making it possible to position the copyboard 111 in a higher place and the platen 120 in a lower place. The process camera shown in figs. 2 through 4 operates in the same manner as the process camera shown in fig. 1. Therefore, operation of the process camera of figs. 2 through 4 will not be described below. According to the embodiment shown in figs. 2 through 4, inasmuch as the optical path is inclined to the vertical direction such that the first mirror 114 above the copyboard 111 is positioned higher than the second mirror 118 above the platen 120, the required optical path length can be maintained even if the copyboard 111 and the platen 120 are closely positioned until they partly overlap each other. As a result, the process camera is rendered more compact in size.

Claims: A process camera comprising: a horizontal copyboard (11) for supporting an original to be copied; a horizontal platen (20) for supporting a photosensitive member, the platen being horizontally movable for the exposure of a selected area of the photosensitive member; a mask plate assembly (48) positioned above said horizontal platen (20) to provide an aperture for the exposure of the selected area of the photosensitive member; a focusing lens (16) defining an optical path, for forming an image of the original; a first mirror (14) disposed in the optical path and above said horizontal copyboard (11) for redirecting light from said copyboard (11) to said focusing lens (16); a second mirror (18) disposed above said horizontal platen (20) and movable into and out of the optical path between said focusing lens (16) and said horizontal platen (20), said second mirror (18) redirecting the light from said focusing lens (16) towards said horizontal platen (20), so that the image of the original is formed on said horizontal platen (20), when said second mirror (18) is moved into the optical path; an index plate (24) positioned in the optical path such that the image of the original is formed thereon, when said second mirror (18) is moved out of the optical path; and said focusing lens (16) being further arranged to form an image of the index plate (24) onto said copyboard (11), when said second mirror (18) is moved out of the optical path. A process camera according to claim 1, wherein the optical path extending from the first mirror (14) disposed above said copyboard (11) through said focusing lens (16) and said second mirror (18) to said index plate (24) is inclined such that said first mirror (14) above said copyboard (11) is positioned higher than said second mirror (18). A process camera according to claim 1, wherein said horizontal platen (20) is movable in a plane parallel to the surface of the photosensitive medium in X and Y directions extending perpendicularly to each other. A process camera according to claim 1, wherein said horizontal platen (20) has a suction device for attracting the photosensitive medium supported thereon. A process camera according to claim 1, further including a feed screw (40) for moving said focusing lens (16) along the optical axis.

Inventors: YAMASHITA MIYUKI, YAMASHITA, MIYUKI
Applicants: HIRAKAWA KOGYOSHA KK, HIRAKAWA KOGYOSHA CO., LTD.
Application year: 1989
Main classification: G03B27
IPC codes: G03B27