Abstract: An original table for use with an imaging apparatus or the like of a type wherein an original to be imaged is held in position by suction is disclosed. The surface of the table having holes through which air is drawn to provide the suction is covered with a sheet of nonwoven fabric having a high air permeability and high light reflectance. The sheet of nonwoven fabric is selectively coverable by an overlay member made of a transparent material that can be selectively applied over and detached from the sheet of nonwoven fabric in the case a paste-up or the like is to be imaged.

Abstract: Vacuum printing apparatus is provided including a light box having an upwardly facing ground glass illuminated surface. A manually movable vacuum box is movable independently of the light box and is operated face down with a vacuum chamber above the photosensitive printing material and a transparency, the vacuum box resting on the light box for exposure.

Abstract: A process camera including a lens or lens system movably mounted for focussing light with respect to a glass sheet serving as an image plane and a vacuum-operated frame back provided with a flexible blanket having a surface relief configuration on its contacting surface for holding by contact therewith a photographic material against the said glass sheet, characterized in that the edges of the glass sheet are provided with a material absorbing light to which the glass sheet is transparent.

Abstract: There is disclosed an equipped table for making marked off sheets reproducing the outline of the templates or stencils of a model as used in the textile cloth article field.The table essentially comprises a horizontal transparent bearing surface or plate, provided with a plurality of small through holes, thereunder there is formed a closed gap, coupled to a sucking device and including a number of illuminating lamps.At one end of the mentioned surface, moreover, there is located a development chamber, including ammonia heatable tanks and provided with a system for forcibly circulating air in the inside thereof.Thus a plurality of marked off sheets may be made by a single template arrangement, the made sheets being perfectly dry and devoid of any odors.

Abstract: There is described an improved vacuum sheet for use in contact vacuum frames, the sheet including at least two planar sheets of material joined together to form a seam therebetween, and a third planar sheet of material applied to one side of said at least two sheets to be substantially centered over the seam formed therebetween.

Abstract: A contacting method comprises the steps of holding a photomask and a wafer at a predetermined interval, curving at least one of the photomask and the wafer so as to form a convexity relative to the other, and moving the photomask and the wafer relative to each other to bring them into intimate contact with each other.

Abstract: A stencil exposure apparatus that includes a frame with central translucent stencil mounting surface. A plurality of generally flat, resilient, compressible seal elements extend between opposite sides of the translucent surface and are movably mounted on the frame in order to accommodate the stencil exposure apparatus to a variety of stencil dimensions. A stencil mounting bar is movably mounted on the frame and includes means for maintaining the orientation of the bar relative to the frame while the mounting bar is being moved.

Abstract: An apparatus for exposing boards which are photosensitive on both sides, for production of printed circuits on both sides, to light through films on both sides in which a lower film, a board, and an upper film in registered position on a light-transmitting platen are pressed down by a window and exposed to light on both sides through the platen and window. A pair of registration pins are adjustably positioned in spaced relation along an edge of the platen and corresponding holes in the boards are used to align the boards and films for exposure. The pins are spaced as widely apart as possible to provide maximum registration between boards of varying sizes and films.

Abstract: In a semiconductor exposure apparatus having chucks for holding a mask and a wafer, respectively, the holding portion of at least one of the chucks has a coefficient of linear expansion equal to or smaller than the coefficient of linear expansion of the bodies held. Particularly, the coefficient of linear expansion of the holding portion of the chuck should preferably be of a small absolute value, but even where the absolute value of the coefficient of linear expansion is great, the chucks are usable by providing temperature control.

Abstract: A vacuum frame is provided with a work surface with a known reference center point. Two vacuum chambers on the underside of the work surface are included for a lithographic plate and an image carrier. Vacuum motors associated with the two vacuum chambers, upon actuation, cause the lithographic plate and image carrier to be tightly drawn up against the work surface through a plurality of small apertures formed through the work surface and communicating with the vacuum chamber. A plurality of arrays of registering pins are disposed in the work surface, each array having a known relationship to the center of the work surface. Each registering pin is adjustable to be flush with or project at selected elevations above the work surface.

Abstract: In a vacuum printer for the graphic arts having a bed, a blanket frame upon the bed including a flexible impervious blanket having a peripheral sealing bead, a glass frame including a glass, with the glass in snug flexing and sealing registry with the blanket bead defining a contact printing chamber, the glass frame being movably mounted for opening and closing movements relative to the blanket frame, and a vacuum source having a first vacuum conduit communicating with the printing chamber for evacuating it; the improvement which comprises a non-metallic base plate positioned within and yieldable mounted upon the blanket frame supportably underlying the blanket. A flexible apertured skirt at its outer and inner periphery is sealed respectively upon the blanket frame and the base plate, defining with the blanket a vacuum chamber connected by a second conduit to the first conduit.

Abstract: A vacuum frame is provided with a work surface with a known reference center point. Two vacuum chambers on the underside of the work surface are included for a lithographic plate and an image carrier. Vacuum motors associated with the two vacuum chambers, upon actuation, cause the lithographic plate and image carrier to be tightly drawn up against the work surface through a plurality of small apertures formed through the work surface and communicating with the vacuum chamber. A plurality of arrays of registering pins are disposed in the work surface, each array having a known relationship; to the center of the work surface. Each registering pin is adjustable to be flush with or project at selected elevations above the work surface.

Abstract: An apparatus for exposing photosensitive media is disclosed in which the light reaching the photosensitive layer of the media is monitored, with the exposure being terminated after the desired amount of light has been received. A multiple exposure control is also provided which adjusts the relative exposures during first and second exposures of the photosensitive material. A special roller curtain mechanism is also disclosed. In addition, the apparatus includes a vacuum system for generating a vacuum, as the curtain descends with the vacuum being drawn between the blanket or curtain and a glass plate which supports the sensitized media and originals being copied. The surface supporting the sensitized materials is inclined to facilitate loading and unloading of the apparatus and also the operation of the curtain.

Abstract: An original holder or like device for bringing a sheet into a flat exposure plane in a reprographic apparatus comprises a transparent resilient support plate which normally is resiliently held slightly bowed and a rigid flat pressure plate such as a glass plate which can be pressed onto the convex side of the support plate to bring the support plate and a sheet resting on it into a flat position for exposure of the sheet.

Abstract: In a vacuum film holder, a mounting plate for situating film registration pins at locations coinciding with the vacuum channel which holds the film against the glass pane covering the center of the film holder frame. The plate bridges the vacuum channel and fits partially in a groove formed in the frame and partially in an aligned notch formed in the glass. Locator pins and cooperating diamond-shaped pins on the plate fit in holes drilled through the frame within the groove to assure proper location of the registration pin in coincidence with the vacuum channel. A special tool permits the plate to be easily removed without damaging the glass of the film holder.

Abstract: A photographing station of a copying camera is disclosed comprising a film supporting surface rotatable about its axis between a first position and a second position. The surface receives and holds a predetermined length of unexposed film in the first position, turns to the second position for exposing the film and then resumes the first position to remove the exposed film for developing.

Abstract: An improvement in printing machines used in photolithography, repro work, screen printing, and bromography having a glass plate and a vacuum table between which, for example, a film containing the drawing to be reproduced and the plate to be engraved are laid, after which the air between the superimposed plates is sucked out by means of a vacuum pump, characterized by the fact that the underside of the glass plate has a finely-grained rough surface, across which the air is able to escape on all sides.

Abstract: A contact printer in which, when a spring roller is rolled over a transparent plate on which an original plate and a photosensitive material are laid one on another, a flexible airtight sheet wound round the spring roller is extended to cover the transparent plate. The distance between the transparent plate and the spring roller is gradually reduced as the spring roller is rolled rearwards, so that the distance between the transparent plate and the point of contact of the airtight sheet to its own rolled part wound round the spring roller is maintained substantially to a fixed value, thereby contacting the original plate and the photosensitive material onto the transparent plate tightly. A squeeze roller may be provided for squeezing air from a space between the transparent plate and the airtight sheet by rolling thereon. A lower step on which the spring roller and the squeeze roller may be held when the printer is not used, can be formed in the front top end of a frame body.

Abstract: In copying machines, cameras etc. the blanks (6, 7) are placed between a glass plate and a support consisting of a rubber cloth (1), which is supplied with a circumferential bead (2). By exhaustion of the field of activity (5) of the rubber cloth (1) the blanks (6, 7) are pressed firmly against the glass plate, and in order to obtain an even exhaustion of the whole field (5) the rubber cloth (1) is supplied with a strip (3) of rubber or plastics along the bead (2) with transversing ducts (4), which are in connection with exhaustion openings (9).

Abstract: A wet modular film printer having a plurality of removable modules upon which film printer components are mounted including a liquid immersed, capstanless printing head. The printing head immersion liquid is continuously recirculated and filtered by means of a recirculation draw off near the top of the liquid surface and a recirculated liquid return downstream of the printed head. Liquid containing areas are all enclosed and a negative pressure is maintained to remove any noxious vapors. After printing, the liquid remaining on the raw stock and the negative is removed by a series of wipers, an air stripper and a drying column. The drying column uses heated air which flows countercurrent to the direction of film movement so that the air is progressively hotter along the film's path of movement.

Abstract: For contact-printing an original such as a photographic negative on a light-sensitive material a vacuum printing frame is provided which comprises a first vacuum chamber between a light-transmitting plate and an elastic diaphragm, and a second vacuum chamber opposed to the first vacuum chamber across the diaphragm. The two vacuum chambers are evacuated simultaneously, with the original and sensitive material mounted in superposition in the first vacuum chamber. Upon subsequent introduction of atmospheric pressure into the second vacuum chamber the original and the sensitive material make close, uniform contact with each other, thereby making themselves ready for exposure. Another embodiment employs a third vacuum chamber disposed opposite to the first vacuum chamber across the light-transmitting plate. Evacuated simultaneously with the first and second vacuum chambers, the third vacuum chamber makes possible the use of a thinner light-transmitting plate, which normally is of glass.

Abstract: Apparatus for exposing lithographic plates to light through a film, e.g. a negative, adapted for exposing a plurality of plates to light through the same film, having a conveyor with grippers for conveying a plate with a film thereon to an exposure station, where a window comes down on the film and plate, the grippers being opened to allow the window to vacuum-lift the film off the plate and retain it while another plate is conveyed to the exposure station for exposure through the retained film.

Abstract: A baseboard for retaining a photosensitive plate thereon is fixedly disposed immediately below an exposure light source and in a path provided by means for feeding the plate to the baseboard and means in alignment with the feeding means for delivering the plate from the baseboard after exposure. A frame for superposing a negative film and a stiff transparent sheet on the photosensitive plate fed to the fixed baseboard is provided with squeegee rolls which are rollable on the transparent sheet to press out and remove air from between the film and the plate. With frame moved upward and downward relative to the fixed baseboard, the apparatus performs the successive steps of feeding the plate, removing the air, exposing the plate and discharging the exposed plate.

Abstract: Apparatus and method are disclosed for use in replicating information from a master record carrier, such as a videodisc, onto a replicate material in web form. In a preferred embodiment, the disclosed replication apparatus comprises supply, exposure and takeup chambers. A web cleaning device in the supply chamber cleans the replicate material of foreign particles. In the exposure chamber, the replicate material and a master record carrier are brought into close contact in order to make a contact print exposure. The exposed replicate material is stored in the takeup chamber.

Abstract: A contact printer, for exposing light sensitive sheets to relatively large size drawings and the like for making accurate duplications, is formed of an endless, movable, support belt having a flat support surface which is overlapped by a movable transparent belt. The drawing and sheet are overlapped and fed between and move in a longitudinal direction with the two belts. The overlapping portions of the transparent belt, the drawing and sheet are all flattened and tightly clamped together against the flat support surface by a vacuum system. Such system includes closely spaced, transversely extending, grooves formed in the surface of the support belt. The grooves open endwise into longitudinally extending border portions which are formed along the side edges of the support belt. A row of holes through at least one of the border portions passes over a vacuum chamber. Thus, air is evacuated through the grooves and out through the holes to the chamber.

Abstract: An original document handling apparatus for moving successive individual document sheets on the surface of a movable belt into a registered position for copying at a copier imaging station, including registration fingers movable into and out of the path of the documents, in which the belt has a plurality of narrow elongated grooves extending in the direction of movement of the belt and having gently sloped walls to avoid reproducible shadows, and wherein the registration fingers are adapted to interfit into the grooves for the registration of the documents. The grooves preferably also include vacuum apertures therein.

Abstract: In a document handling system in which an apertured vacuum belt transports the documents to the imaging station of a copier and provides a light reflective background surface, the belt vacuum apertures are only within discrete limited areas of the belt and have a convoluted surface which holds the document spaced from the vacuum apertures and provides low impedance air flow under the document from the apertures, said areas being substantially enclosed by narrow border areas of unapertured and non-imageable pneumatic weirs at positions corresponding to the edges of conventional sizes of documents, which weirs are finely convoluted to have a much higher air flow impedance.

Abstract: In a document handling system in which documents are moved on an apertured belt over a vacuum manifold to an imaging station of a copier, the vacuum manifold surface engaging the backside of the belt contains narrow, spaced apart, shallow grooves extending in the direction of movement of the belt. Vacuum is applied to the belt only through these grooves, to reduce belt/manifold friction. These manifold surface grooves have light reflective bottom surfaces closely spaced below the back of the belt to underlie the belt apertures and reduce their printout through translucent documents. The apertures in the vacuum belt are only in narrow bands overlying the grooves in the vacuum manifold. The apertures in the vacuum manifold are also preferably transversely spaced from the vacuum belt apertures so that they are not aligned during the belt movement.

Abstract: In an apertured vacuum belt document handling system for a copier, with a normal vacuum transport mode for moving the belt with a document thereon over the exposure position, the belt is provided with an unapertured area, preferably larger than the exposure area. This unapertured area is automatically positioned and stopped over the exposure station when the copier is placed in a manual document placement mode of operation.

Abstract: A closed container or tank containing a body of liquid within which is totally immersed an endless loop of flexible web material such as motion picture film, with said flexible web material wound in a multiple loop within the container, and provisions for an extended loop portion of said flexible web material to enter and exit the tank at the same rate of speed. The extended loop portion of said flexible web is designed to run through a second apparatus such as a motion picture printing machine in a continuous and uninterrupted path.

Abstract: A conveying mechanism and flexible carrier for transporting a planar printing plate and flexible overlying mask from a flat loading station to a precisely-curved cylindrically-shaped scanning station, and back to the flat loading station, is disclosed. The vacuum carrier used is rigid in one axis and flexible in a second axis, and has a pair of reference strips which define a neutral bending axis for the plate and mask when the latter are wrapped around a pair of precisely machined cylindrical discs. By locating the flexible mask and printing plate outside the neutral axis of bending, both are placed in tension when wrapped around the discs. This maintains uniform contact between the plate and mask and prevents wrinkling of the mask as it overlies the plate.The carrier and discs support the plate and mask within a precise and uniform cylindrical plane for scanning with focussed beams of radiation.

Abstract: Apparatus and method are disclosed for use in replicating information from a master record carrier, such as a videodisc, onto a replicate material in web form. In a preferred embodiment, the disclosed replication apparatus comprises supply, exposure and takeup chambers. A web cleaning device in the supply chamber cleans the replicate material of foreign particles. In the exposure chamber, the replicate material and a master record carrier are brought into close contact in order to make a contact print exposure. The exposed replicate material is stored in the takeup chamber.

Abstract: Apparatus and method are disclosed for contact printing information from a master record carrier onto a replicate material of a type that emits gas during the contact print exposure (e.g., a diazo-film emulsion). It has been discovered that the emitted gas acts as an efficient lubricant of the master-replicate interface and contributes to relative movement between the master record carrier and the replicate material during the contact print exposure. In the case of videodisc replication, wherein video information is recorded in the form of billions of micron-sized apertures, such relative movement severely degrades the replicated imagery. To limit such relative movement, a preferred embodiment of the present invention provides contact printing apparatus, including a specially filtered exposing source, that substantially eliminates relative movement between the master record carrier and the replicate material.

Abstract: A method of making a mask and a wafer intimately contact each other by means of such a mask aligning apparatus comprising a base having a chamber, a piston apparatus movable up and down in the chamber, a wafer chuck provided at one end of the piston apparatus and adapted to fix the wafer, means for fixing the mask to the upper surface of the wafer in a superposed relationship, drive means adapted to impart a driving force to the piston, so as to move the wafer toward the mask, and means for biasing the piston apparatus in the direction to move the wafer away from the mask.

Abstract: A photographic exposure unit for making a reproduction of non-dimensional engineering drawings to very close tolerances. The original drawing and the film are driven by a travelling vacuum system through a light exposure unit. In all cases, the exposure is made while the original drawing and film are held in close contact one against the other during their conjoint passage through a flat exposure area.

Abstract: In certain types of printing applications (for example optical or magnetic contact printing) wherein it is desired to transfer imagery from a master device to a replicate device, providing and maintaining close contact between the master device and the replicate device poses certain problems. These problems become even more acute if the surfaces to be contacted are of large area. In accordance with the present invention, close contact over even large areas is obtained between a master device and a replicate device by forming a thin and uniform liquid layer between the master and replicate devices, thus producing a vacuum effect which serves to tightly press the master and replicate devices together.

Abstract: An optical distortion device which can make a contact copy of a photographic film image with one dimension of the copy lengthened or shortened while the perpendicular dimension is unchanged is comprised of a pair of cylindrical motor driven rollers, at least one of which can be driven at a very low speed. The axes of the rollers are disposed parallel to each other and to a narrow slit through which a beam of light is directed. A copy sheet such as a photographic negative and a sheet of photosensitive material are pressed into intimate contact as they pass over the slit by a jet of positive air pressure and each sheet is held to the circumference of a respective roller by negative air pressure selectively supplied to a plurality of grooves in the surface of the roller.

Abstract: A pattern reproduction table incorporates a support grid which supports a transparent perforated sheet above a plurality of lamps. The support grid comprises a plurality of thin polished longitudinal and transverse members which are interlocked and which are mounted in tension on an enclosure. The support grid provides rigid support for the transparent perforated sheet without obscuring the lamps or interfering with a vacuum blower which is mounted in the enclosure.

Abstract: A printing tank contains a body of transparent liquid within which a main printing sprocket is totally immersed. Mechanism is provided for feeding one edge of a master strip of film onto the sprocket and in a curved path around a portion of the circumference of the sprocket. A curved support is provided to support the other edge of the master strip of film in a parallel relationship. An illuminated window is positioned between the sprocket and the curved support. A space between the window and the master strip of film is filled with the transparent liquid.In operation, the master strip of film is sprocket-registered while passing the printing aperture effected by the illuminated window. Means are also provided for transporting an unexposed strip of film in sprocket registry with the master strip of film at the aperture.PRIOR ARTContinuously driven printing machines for transferring photographic images from one moving strip of film to another are well-known, one being shown, for example, in the Jeapes Pat. No.

Abstract: Apparatus for supporting a sheet of photosensitive material in the image plane of an optical imaging system for exposure thereat. The apparatus includes a first cover plate assembly having a transparent cover plate and a second backing plate assembly including a relatively flexible backing sheet. The cover plate assembly is driven into contact with the backing plate assembly with the photosensitive sheet to be exposed supported therebetween such that an air-tight chamber is defined between the cover plate assembly and the relatively flexible backing sheet. The air-tight chamber is then evacuated through the cover plate assembly, and as it is evacuated, the flexible backing plate will be sucked towards the cover plate assembly and drive the photosensitive sheet into firm contact with the transparent cover plate.By the use of the flexible backing plate, the chamber can be evacuated very rapidly, for example, in two or three seconds.

Abstract: Stencil exposure apparatus having a flexible compressible peripheral seal element suspended by a plurality of radiating tension straps in a selected configuration between a translucent stencil pattern support surface on one side, and a stencil fabric layer retained in a stencil frame or chase on the other side, there being a suction connection for the space enclosed by said seal, said translucent surface, and said stencil fabric.In one apparatus embodiment disclosed, the peripheral seal is a traveling seal suspended on a stencil frame carriage which is selectively shiftable relative to the translucent surface and supports the stencil chase.In another apparatus embodiment disclosed, the tension straps are shiftable to vary the dimensions of the area enclosed by the peripheral seal.

Abstract: A vacuum contact printer for printing indicia formed on a translucent drawing sheet onto a sensitized sheet material. The contact printer includes a vacuum chamber defining an enclosure having a planar upper wall with vertically directed through perforations. Secured to the upper wall of the vacuum chamber is a screen element which is pulled taut and located in fixed relation to an upper surface of the upper wall of the vacuum chamber. A cloth member is positioned over the screen member and secured to the frame of the vacuum chamber.In order to provide an image, the drawing sheet and sensitized sheet material are inserted over the cloth member and sandwiched between a transparent polyester film and the cloth. A light fixture is linearly driven across the upper surface of the vacuum chamber and the various sheet mounting mechanisms in close proximity thereof to permit light to pass through the translucent drawing sheet onto the sensitized sheet material.

Abstract: A jig for positioning an image mask and image receiving medium which includes a housing having a central bore, first means within the bore for supporting a mask or image receiving medium, a flexible diaphragm, second means for drawing vacuum, and a third means for applying superatmospheric pressure on one side of the diaphragm to deform it towards the first means to ensure proper positioning of the mask and image receiving medium. Also, the process for positioning the mask and image receiving medium is provided.

Abstract: A printer for exposing photographic material is shown with a printing table horizontally mounted within a cabinet to receive photosensitive material and copy. A transparent plate is pivotably attached to hold the photosensitive material and copy in contact above the table which may be of the vacuum type. The front of the vacuum table may or may not exceed beyond the front of the cabinet. A fixed panel may be provided to support an exposing light above the table, additionally the control panel and shutter mechanism may be part of this fixed panel. A movable plate at least partially opaque to actinic rays may be moved inwardly as the transparent plate is raised. A safelight, viewing or inspection light may be mounted within the cabinet. A lifting and latching handle may be mounted at the front edge of the transparent plate.

Abstract: A microfiche or microfilm editing device in which a microfilm or microfiche to be edited is supported on a frame arranged to be driven in an x and y axis directions according to a program, the movements being relative to a copy axis. Also movable in relation to the copy axis is a microfiche holding means arranged to be driven by actuators in a similar fashion to the first microfiche or microfilm and according to a further program. In order to illuminate the image to be transferred to the first film to the second film a light source condenser and at least one light transfer block is arranged to project light along the copy axis. Several light transfer blocks may be mounted on a rotatable turret so that different blocks may be provided for different microfiche or microfilm standards.The editing device is arranged so that microfiches can be updated according to a set program or alternatively microfilm can be changed to microfiche or microfiches and one standard can be changed to microfiches of another standard.

Abstract: Method for the production of a serigraphic screen by the photochemical method, characterized by the fact that, starting from a blank tubular screen obtained by tubular weaving or by closing a flat fabric on itself, one at least of the faces of the screen is coated with a photosensitive film, against the screen is placed a transparent tubular masking film bearing the design to be printed in ink in opaque zones, stretching the masking film and the screen axially and radially, under the conditions of tension wherein the finished screen will be used for the printing, urging the screen and the masking film against one another, and exposing to actinic rays, on the side of the masking film, the assembly of the superimposed masking film and screen, the photosensitive film being then removed by washing in the zones of the screen covered by the opaque zones of the masking film during exposure, while it remains in the irradiated zones.

Abstract: A process and apparatus for exposing light-sensitive printing plates through an original to be copied, which includes forming a cassette-type, vacuum frame assembly by superimposing the printing plate and the original upon one another and disposing them in a cavity formed between an elastic blanket and a light-permeable plate, and evacuating the assembly, to improve contact between the printing plate and the original, at a position removed from a light means, thereafter temporarily placing the assembly in a position to be exposed to the light means and finally removing the assembly from the exposure position. A vacuum frame assembly is provided having a connect-disconnect means for temporary attachment both to the evacuation means removed from the light source and, if desired, to an evacuation means at the exposure position.

Abstract: The apparatus described facilitates the registry of image bearing transparencies with a plate having a photosensitive coating thereon. After exposure to light, the plate typically is subjected to chemical milling processes to produce printed circuit boards and the like. The registry apparatus includes upper and lower frames which form an enclosed region therebetween in which the plates and transparencies are placed in sandwich relationship. An outer gasket between the frames permits a vacuum to be applied to the enclosed region. An inner perimeter channel is formed in the opposed faces of each frame to permit a separate vacuum to hold the transparencies in place while the frames are opened to remove, insert or replace a plate. Successive plates may be processed without the necessity of re-registering the transparencies prior to each exposure.

Abstract: In a vacuum contact printer there are provided a winding roller to which one end of a resilient vacuum sheet is attached and a pressure roller for pressing the sheet against a glass plate. Along with the advancement of both rollers, which are rotatably supported on a pair of bearing plates movable in a longitudinal direction, the sheet automatically spreads over the glass plate, being wound off the winding roller and simultaneously being pressed by the pressure roller so that all the air kept between the sheet and the glass plate is completely expelled. In addition, a suctorial operation encourages a closer adhesion of the sheet to the glass plate, whereby a document and a sensitive material placed between them can be sufficiently in close contact with each other.

Abstract: A predetermined small spacing or gap between a semiconductor wafer and a mask is defined by projecting a cushion of air through a central mask aperture toward the wafer. The wafer is supported on a sponge rubber member which is designed, along with the air flow paths, to maintain a uniform small separation as is desirable in the photolithographic printing of semiconductor mask patterns.