Contact printing apparatus and method

Claim 2

A contact printer as in claim 1 in which said vacuum chamber sealing means consists of a plurality of passages formed in said carrying means, the passages being interconnected at their outer end to said vacuum source and terminating at their other end in recesses positioned adjacent said chamber.

Claim 3

A contact printer as in claim 1 further including means for controlling the exposure of said light source to said photosensitive plate.

Claim 4

A contact printer as in claim 1 in which said carrying means consists of a flexible bag means surrounding said master and photosensitive plates and said means for establishing a vacuum includes an aperture in said bag means.

Claim 5

A contact printer as in claim 1 further including delay means associated with said means for selectively connecting a vacuum pump and said light exposure controlling means for beginning said exposure a predetermined period of time after said vacuum has been applied to thereby allow for adequate diffusion and outgassing of the region between said plates.

Claim 6

A contact printer as in claim 6 including wave length selective filter means rotatably mounted between said light source and said plates, and means for rotating said filter means.

Claim 7

A contact printer as in claim 6 in which said light exposure controlling means includes a shutter system actuated for movement away from said light source by said delay means.

Claim 8

A contact printer as in claim 8 in which said shutter system includes a non-actinic filter.

Claim 9

A contact printer as in claim 1 in which means are provided for directing the exhaust of fumes from the light source away from said contact printer.

Claim 10

In a precision optical contact printer for exposing a planar photosensitive plate to an image borne on a master plate, a light source, means for controlling the output of said light source, an exposure frame including means for carrying said photosensitive plate and said master plate in face-to-face contiguous relation in intimate contact with each other and means for defining a positioning limit about the perimeter of each of said plates to limit lateral movement thereof, means for establishing a generally planar gasket for supporting one face of said master plate about the peripheral margin thereof facing said light source, means associated with said gasket and said positioning limit means and adapted to cooperate with the adjacent rear surface of said photosensitive plate to establish a vacuum sealed chamber in the region surrounding said master plate and said photosensitive plate and including portions of said frame for surrounding the peripheral margin of the plates, duct means communicating with said surrounding frame portions and a flexible sealing flap for covering the rear of said frame, means for selectively connecting a vacuum pump to said duct means so that when a vacuum is drawn in the region of separation between said gasket and said flap is maintained at said vAcuum pressure whereby the atmospheric pressure compresses against the outer faces of said master plate and said photosensitive plate to obtain uniform contact therebetween.

Claim 11

In a precision optical contact printer for exposing a planar photosensitive plate to an image borne on a master plate, said plates being of different planar sizes, a light source, means for controlling the output of said light source, an exposure frame including a base frame for carrying the larger plate and a subframe for carrying the smaller plate, means for pivotally mounting said subframe to said base frame to place the smaller plate in intimate face-to-face contact with a central portion of said larger plate, first sealing gasket means disposed between the subframe and a surface of the larger plate bordering the edges of the smaller plate, annular wall means disposed adjacent to and closely spaced apart from an internal face of said subframe to form an annular chamber therewith, said wall means being movable to a position adjacent the outer peripheral margin of the smaller plate and second gasket means forming a seal between said wall means and said smaller plate, duct means in said subframe communicating with said chamber, and means for selectively connecting a vacuum pump to said duct means so that when a vacuum is drawn said first and second gaskets form seals for maintaining said annular chamber under vacuum whereby the atmospheric pressure compresses against the outer faces of said master plate and said photosensitive plate to obtain uniform contact therebetween.

Claim 12

A contact printer as in claim 12 in which said larger plate is a master plate facing said light source.

Claim 13

A contact printer as in claim 12 in which said smaller plate is a master plate facing said light source.

Claim 14

A contact printer as in claim 12 in which said wall means pivotally mounted to said subframe and including sheet portion extends across said wall means spaced apart from said smaller plate to form an enclosure and selective means for drawing a vacuum in said enclosure for positioning said smaller plate and for releasing the vacuum to atmospheric pressure for printing.

Claim 15

A contact printer as in claim 8 including a third sealing gasket means extending between said wall means and said subframe and forming a vacuum seal for said annular chamber.

Claim 17

A method as in claim 17 wherein the edges of the photosensitive and master plates are generally coincident and the vacuum is applied at said edges.

Claim 18

A method as in claim 17 wherein the master plate and photosensitive plate are of different sizes and the vacuum is applied at the edges of the smaller plate and at a surface of the larger plate in the vicinity of said edges.

Claim 19

A method as in claim 17 wherein said predetermined time period is from about 5 to 40 seconds.

Claim 21

In a method for contact printing by directing light from a source through a master plate onto a photosensitive plate, the steps of placing the master plate and photosensitive plate in contact with each other so that the master plate faces the light source but is substantially unexposed to developing light emitted therefrom, maintaining atmospheric pressure at the outer surfaces of said plates and simultaneously applying a vacuum throughout an area in common between said plates until said vacuum falls to a sufficiently low pressure to begin substantial outgassing between said plates, sensing said low pressure value, actuating an exposure delay timer in response to said sensing while maintaining the vacuum to thereby expose said plates to light from said source only after a predetermined period of time after said sensing for effectively complete outgassing between said plates, measuring by light sampling the total time integrated amount of exposure received by the plate, releasing the vacuum, and removing the exposed photosensitive plate.

Claim 22

A method for contact printing as in claim 18 in which said lighting is selectively filtered during exposure.

Claim 23

In a precision optical contact printer for exposing at least two planar photosensitive plates to images borne on two corresponding master plates, a light source, means for controlling the output of said light means, at least two exposure frames, means for mounting said exposure frames in spaced relation along an arc centered generally at said light source, each of said exposure means for carrying a set of said photosensitive plates and said master plates in face-to-face contiguous relation in intimate contact with each other, means for establishing a vacuum sealed chamber in the region surrounding each of said master plates and said photosensitive plates and including portions of said frames for surrounding the peripheral margin of the plates, duct means communicating with said chamber, means for selectively connecting a vacuum pump to said duct means so that with said sealed chamber under vacuum atmospheric pressure compresses against the outer faces of each of said master plates and said photosensitive plates to obtain uniform contact therebetween and vacuum switch means associated with each of said frames for selectively or non-selectively operating the same.