Abstract: A vacuum frame apparatus including a latching system with means to assist in repressurizing the vacuumized area of the frame includes a vacuum blanket support frame pivotally mounted along one side of a glass panel for holding workpieces in precise registration against the glass panel for making copies includes a hollow rectangular frame around a flexible vacuum blanket. The frame members have a plurality of small vacuum ports on the underside inside a peripheral bead seal for evacuating the space between the flexible vacuum blanket and the glass panel when a vacuum is pulled on the interior of the hollow peripheral frame by a vacuum pump. Large size frontal ports are provided on the front side member of the frame to cooperate with batch mechanisms for clamping and holding the frame tightly against the glass panel during copy making.

Abstract: Vacuum frame apparatus is provided for maintaining precise registration between and an image forming sheet to be reproduced and a light sensitive sheet adapted for controlled exposure to light. The apparatus includes a light transmitting glass panel having a planar surface for contact with the image sheet and a vacuum blanket assembly including a blanket of thin, flexible sheet material adapted to contact the light sensitive sheet and bias the sheets toward the planar surface of the glass panel while maintained in precise registration. The vacuum blanket assembly includes a peripheral edge seal around the blanket for sealing engagement with the planar face of the glass panel and means for evacuating the space inside the peripheral edge bead between the planar face of the panel and the blanket of the vacuum blanket.

Abstract: A vacuum blanket apparatus for maintaining precise registration between an image forming sheet and a light sensitive sheet when subjected to controlled exposure to light passing through a glass panel includes a vacuum blanket having an upper cover of flexible sheet material adapted to contact the light sensitive sheet for biasing the same and said image sheet toward a planar face of the glass panel when the panel is locked in position parallel to the vacuum blanket. The blanket cover is formed with at least one elongated slot for receiving one or more registration pins for registering the image forming and light sensitive sheets. At least one deformable resilient pressure element in the slot is deformable to bias the sheets toward the glass panel.

Abstract: A new and improved graphic arts device for exposing copy sheets to controlled light from a light source passed through an image sheet includes a light source and a glass frame including a rigid panel of transparent material having a surface against which an image sheet and a copy sheet are pressed during an exposure cycle. A vacuum blanket is provided for biasing the image and copy sheets against the planar surface of the transparent panel. A yoke is provided for supporting the glass frame between the vacuum blanket and the light source at a convenient working level for movement between a horizontal, closed position used during exposure and a second, upwardly sloping open position for permitting removal and placement of the image and copy sheets on the transparent panel. The glass frame is normally locked in position on the yoke but can be unlocked for a full 360.degree. pivotal action about a central axis of the frame extending transversely between opposite legs of the yoke at said points thereon.

Abstract: A light-modifier for changing the character of light flowing from a light source towards an image forming sheet and a sheet of light sensitive copy in an exposure device includes a roll of thin, flexible light-modifying plastic sheet material which is rotatably mounted for rolling and unrolling on a roller to extend between a first light-intercepting unrolled position extending outwardly between said image forming and copy sheets on the one hand and said light source on the other hand and a second, rolled-up position offset from the copy sheet. The apparatus may be made for sale as an accessory or optional item for a wide variety of existing exposure devices whenever it is desired to change the character or form of the light energy by diffusion, filtering or attenuation, and the apparatus may be directly incorporated as an integral part of a new exposure device.

Abstract: A graphic arts exposure device includes a cabinet defining a work surface at a convenient working level and having a forward wall facing an operator utilizing the device. A drawer is positioned immediately below the working level movable between an extended position outwardly of the forward wall of the cabinet and a retracted position within the cabinet. A control panel for the exposure device is mounted on the drawer facing upwardly in the same general field of view for the operator as the working surface of the device. The drawer is supported on sloped slides in the cabinet below the work surface for movement between the extended and retracted positions and the slides are sloped downwardly and outwardly to automatically bias the drawer and control panel to the outwardly extended position ready for receiving operator inputs of the necessary control data while at the same time allowing the operator to view the control panel and working surface in the same general field of vision.

Abstract: An overhead exposure unit includes a light source for exposing sheets of light sensitive material carried on a supporting table. The light source is mounted at a fixed elevation above a floor or other surface and a support system is provided for moving the film support table up and down beneath the light source to provide the desired distance between the light source and the film for making plates or other photographic reproductions. The film support table is movable between a convenient working level and is raised or lowered to the selected level to provide a desired spacing or distance between the light source and the film while controlled light exposure takes place.

Abstract: An overhead light exposure unit for making copies on pre-sensitized sheets from images on film includes a base supporting a vacuum blanket for pressing the sheets and film together against a transparent panel. The transparent panel is mounted in a frame that is pivotally secured to the base for movement between a closed horizontal position for making copies and an upwardly tilted, open position for unloading and loading film, sheets and media into place. A light source is positioned above the panel for directing controlled, high intensity light downwardly through the panel to reproduce film images on the pre-sensitized sheets held in place by the vacuum blanket. A support system is provided for holding the light source in an exposure position space directly above the transparent panel for directing controlled intensity light downwardly through the panel to reproduce an image on a silk screen, sheet or film held in place by the vacuum blanket.

Abstract: A latch system for a vacuum frame has a plurality of separate latching mechanisms interconnected with a common actuator rod so that the glass frame can be unlatched and raised with one hand.

Abstract: A registration system for exposing photosensitive sheets to controlled light through images formed on film includes a thin, relatively stiff, dimensionally stable support board having a relatively flat upper surface for supporting a photosensitive sheet and an image forming film sheet in overlying relation thereon including an upper layer formed of resilient material and having at least one registration opening extending between opposite faces of the board for receiving a registration pin. The pin includes a stop flange adjacent a lower end for limiting upward movement of the pin in the board and includes an upper body normally projecting above the upper surface of the support board to extend into aligned registration openings which are punched in the photosensitive sheet and the image forming film.

Abstract: The present invention relates to power supplies, and more particularly, to a power supply which is particularly suitable for controlling a high intensity discharge (HID) lamp. In particular, the present invention relates to an HID lamp power supply which provides fast warm up for a cold lamp, regulation against line voltage fluctuations and a lamp starting circuit which provides extremely fast restart when the lamp is hot and has been turned off momentarily.

Abstract: A power supply for a high intensity discharge lamp is provided wherein the secondary windings of a pair of lamp strike pulse transformers are connected in series with the HID lamp directly across the AC supply, the impedance of these secondary windings acting as the only ballast elements of the power supply. The HID lamp is chosen to have relatively high operating and maximum starting currents so that warm-up time of the lamp is dramatically reduced while employing the lamp strike pulse transformers to perform the dual function of starting the lamp when either hot or cold and acting as the current limiting ballast for the lamp both during warm-up and under normal operating conditions.

Abstract: A universal light intergrator/timer is provided for use with photographic equipment wherein several desired exposure intervals for each of a plurality of light sources may be preset and stored in a microprocessor for instant selection by the operator during a photographic operation.When a stable light source is used the system is arranged to function as a timer and counts pulses derived from the AC line to control the light source in accordance with the preset exposure intervals.When a light source is used whose wavelength and intensity varies during warmup, the system is arranged to function as a light integrator. To obtain light integration the current flowing in a photodiode, which is linear with respect to light output, is amplified and converted to variable frequency pulses which are counted by the microprocessor to control the light source in accordance with the present exposure intervals.

Abstract: A bank of high power quartz iodine lamps is regulated so that changes in light output from the lamps for a 40 volt change in AC line voltage is reduced from 132% to 10%. To accomplish this, a regulating pulse width modulator is synchronized to the AC line so that pulse width modulated pulses are developed the trailing edge of which is coincident with the zero crossover points of the AC line voltage. The variable leading edge of these width modulated pulses is employed to control the firing point of semiconductor switching devices in series with the lamps, the average voltage across the lamps being sensed and employed by the regulating pulse width modulator to vary the width of the pulses in the correct direction to maintain the lamp voltage constant despite large changes in line voltage.

Abstract: Apparatus for laminating pieces of sheet material comprising a base of rigid material having a flat upper surface formed with a plurality of spaced apart perforations distributed substantially uniformly over the surface, a support member having a flat upper surface supporting an underside of said base and having a plurality of concentric interconnected grooves defined and in communication with said perforations, means for developing a partial vacuum in said grooves for causing fluid flow through said perforations around one or more pieces of sheet material placed in contact with the upper surface of the base, a cover of flexible, fluid impervious transparent sheet material movable between an open position out of overlaying relation with said base and a closed or overlaying position covering said base along with any pieces of sheet material places on the base to be laminated together and means for sealing around the periphery of said base and said cover when said cover is in said overlaying position.

Abstract: A portable processing station comprising an enclosure having a bottom wall, a top wall, a pair of side walls, a rear wall and a front wall defining an entrance opening, said walls being formed of strong, thin sheet material with integral flange means for joining adjacent ends of said walls forming light tight joints therebetween, a light tight entrance curtain for opening and closing said entrance and means for causing a flow of ventilating air through said enclosure when said entrance curtain is closed.