Abstract: A method for manufacturing a drum assembly for an internal drum-type imaging apparatus, and a drum assembly produced using the method. The drum assembly defines an imaging surface which is at least semi-cylindrical. A drum skin defines an imaging surface, and is releasably wrapped around a cylindrical mandrel, which has an axis. The mandrel and wrapped drum skin have a first radius. A drum includes more than one drum portion, and is attached to the drum skin over an at least semi-cylindrical interface. The drum has a radius slightly greater than the first radius, and the drum and attached drum skin cooperate to define a vacuum chamber. A fluid bearing is generated between the drum skin and the mandrel, preferably by pressurizing the vacuum chamber, in order to separate the drum skin from the mandrel. The drum and attached drum skin are then moved relative to the mandrel and in a direction parallel to the axis to remove the drum assembly from the mandrel.

Abstract: An apparatus for handling media sheets in a photo-plotter includes a plurality of aligning mechanisms for precisely positioning the media sheet relative to a drum of the photo-plotter. Each aligning mechanism has engaged and disengaged positions and include a registration pin having corresponding extended and retracted positions. In the engaged position, the extended registration pins of the aligning mechanisms pass through mounting features formed within the media sheet and are engagable with a plurality of drum openings formed within the drum of the photo-plotter. The present invention ensures that the media sheet is properly placed on the drum and also precisely positions the generated image relative to the mounting features.

Abstract: An automated media transport apparatus and method includes a load module for loading media plates from a flat cassette through one end of an internal drum of an imaging module. Sensors detect the presence of interleaved paper sheets from the media plates being loaded, and paper assemblies remove any interleaved paper sheets. An unload module unloads imaged media plates from the other end of the drum, and position the unloaded plates onto a multi-directional conveyor of the unload module. The conveyor is capable of moving the imaged media plate in one of several directions to other devices for further processing of the media plates.

Abstract: An apparatus for feeding media to an internal drum imaging system includes a pair of parallel rails secured to a support frame that is mechanically isolated from the imaging system. The tracks are parallel to the outer circumferential edges of the internal drum. The feeding apparatus further includes a plurality of media engagement means movably coupled between the tracks. The engagement means are adapted to transport the medium to and from the internal drum along the tracks. Each engagement means includes a rail extending between the tracks and a pair of drive means pivotally connected to the ends of the rail for advancing the rail along the tracks. Each engagement means further includes a lifting means for raising and lowering the rail and a coupling means disposed to the undersurface of the rail for securing the media to the rail.

Abstract: A printing plate for use in lithographic printing has a thermally responsive recording material. A plate is fabricated with a photosensitive emulsion affixed to an upper surface of an aluminum substrate. The plate is first chemically processed so that it is capable of accepting ink (i.e., oleophilic). Thereafter, selected areas of the emulsion are thermally removed, preferably by exposure to a high power laser beam. The plate is ready for immersion into an aqueous ink solution.

Abstract: A multiple beam scanning system for an imaging device, such as a photoplotter and scanner, includes a plurality of scanning assemblies slidably coupled to a spar that extends the length and parallel to the longitudinal axis of a scanning surface of an internal drum. The scanning assemblies simultaneously reflect a plurality of optical beam to or from a plate of media disposed on the scanning surface. A photoplotter includes a plurality of independently controlled optical beam generators that emit an optical beam to a corresponding scanning assembly which then reflects the optical beams to the media. A scanner includes a plurality of optical beam receivers that generate imaging signals indicative of the optical beam reflected from the media by each corresponding scanning assembly. The optical beam generators and receivers may be disposed at one end of the internal drum.

Abstract: A system for light-tight handling of a supply of media between a supply station, a workstation and a collecting station, comprises a media handling apparatus defined by a frame and a housing enclosing an internal confine. Within this confine are a supply station and a collecting station disposed at opposite ends of the frame. A positioning drive is suspended above the supply and collecting stations to move media between the supply, collecting and work stations. A lifting shoe is provided as part of the positioning drive and includes a flexible material handling sheet which assumes a first and a second given radius when respectively energized and reverse energized to engage the media supported in curved form. Also, supply and collecting cassettes are provided with a tambour coverings for respectively automatically uncovering and covering the supported media while still maintained in the light-tight confines of the housing.

Abstract: A method and apparatus for use in improving the accuracy of scanning systems is disclosed and claimed. Systems such as internal drum photoplotters include a raster scanner responsive to control signals for advancing relative to a substrate an optical beam across a substrate surface in a first direction forming a scan line of pixels and for cooperatively advancing relative to the substrate the optical beam in a second direction substantially perpendicular to the first direction. The clock signal which is provided to a spinner to advance the optical beam across the scan line is independent from the pixel clock signal which is provided to control the generation of pixels. There is a memory for storing error compensation signals indicative of compensation needed to remove deviations of the separation between adjacent pixels in said scan line from preferred values thereof.

Abstract: The present invention encompasses a scanning optical system such as internal drum photoplotters that has a raster scanner for advancing a circularly polarized optical beam across a substrate surface in a first direction to form a scan line and for advancing the optical beam in a second direction substantially perpendicular to the first direction. There is a curved platen for receiving a substrate and an apparatus for switching the optical beam polarization between first and second directions in response to polarization control signals;. An encoder generates signals indicative of the position of the optical beam along a current scan line. There is a controller that receives the encoder signals and generates the advancement signals and the modulator control signals. The controller further provides the optical beam polarization switching signals in dependence on the encoder signals such that the optical beam polarization is switched after the completion of the current scan line.

Abstract: A magnetically preloaded air bearing motion system for an imaging system motion system includes a carriage for moving a scanning means along a rigid spar for reflecting an optical feed beam onto media. The carriage includes a pair of orthogonal walls for engaging the orthogonal walls of the spar and an air bearing system disposed therein. The air bearing includes a plurality of permanent magnets secured in a prearranged pattern to the orthogonal walls of the carriage for providing an attractive force to couple the carriage to the spar. The carriage further includes a series of passageways terminating at a plurality of output orifices arranged in a predetermined pattern on the orthogonal walls of the carriage. Compressed air is system is electrically connected to the linear motor for controlling the movement of the carriage along the spar.

Abstract: A photoplotting apparatus is provided. The apparatus comprises an internal drum plotter and a media sheet handling apparatus for sequentially delivering a photosensitive media sheet to the photoplotter for exposure from a stack of such sheets. The photoplotter has reduced turbulence within the drum during exposure of the media sheet, and the sheet handling apparatus includes means for separating the sheets in the stack from interleaves disposed between adjacent sheets in the stack.

Abstract: An apparatus for printing, cutting or otherwise working sheets of sheet material has a friction sheet advance mechanism and a sheet loading mechanism in advance of the feed mechanism having rows of sprocket pins cooperating with complementary rows of sprocket holes in a sheet to assure accurate insertion of a sheet into the sheet advance mechanism and subsequent accurate movement of the sheet through the advance mechanism and past a work station. A photosensor carried by the work head of the apparatus senses one side edge of the sheet as a reference for laterally positioning the work process relative to the sheet, and a transversely extending index edge of an index hole in the proof sheet is detected and used as a reference for the longitudinal positioning of the work process relative to the sheet.

Abstract: An apparatus includes a media handler which is capable of processing a supply of media sheets which can take the form of plates, aluminum or plastic used in lithographic printing presses or the like, or can be film which is advanced to a drum and scanned by a scanning process and thereafter removed from the drum surface by appropriate handling means.

Abstract: A system for light-tight handling of a supply of media between a supply station, a workstation and a collecting station, comprises a media handling apparatus defined by a frame and a housing enclosing an internal confine. Within this confine are a supply station and a collecting station disposed at opposite ends of the frame. A positioning drive is suspended above the supply and collecting stations to move media between the supply, collecting and work stations. A lifting shoe is provided as part of the positioning drive and includes a flexible material handling sheet which assumes a first and a second given radius when respectively energized and reverse energized to engage the media supported in curved form. Also, supply and collecting cassettes are provided with a tambour coverings for respectively automatically uncovering and covering the supported media while still maintained in the light-tight confines of the housing.

Abstract: A method for making a plurality of printing press page printing plates using a drum type raster scanning plate making machine involves making a number of separate printing plates from each sheet of plate making material handled by the machine, thereby increasing the number of printing plates capable of being made during a given period of time in comparison to prior methods using similar machines and making only one printing plate from each sheet of plate making material.

Abstract: An optical beam generator system for use in an imaging system that forms an image in a substrate comprises a beam generator, a mode filter and a state selector. The optical beam has a first power level above an exposure level that exposes the image in the substrate and a second power level below the exposure level which does not expose the substrate. The beam generator generates a near single mode coherent optical beam in response to received command signals corresponding to an "on" state and generates a multimode incoherent optical beam in response to received command signals corresponding to an "off" state. The filter is optically coupled to the beam generator and attenuates an optical component of the received optical beam which is not single mode to a magnitude below the exposure level.

Abstract: An apparatus includes a media handler which is capable of processing a supply of media sheets which can take the form of plates, aluminum or plastic used in lithographic printing presses or the like, or can be film which is advanced to a drum and scanned by a scanning process and thereafter removed from the drum surface by appropriate handling means.

Abstract: A method and apparatus used with a printed circuit board (PCB) defect detection system generates a reference database image of the PCB having tolerances for each individual PCB feature, The invention is characterized by a tolerance database of at least three states in which each color is weighted and adjacent pixels are grouped into arrays or "bins". An error signal is generated when the sum of the pixel weights in a bin exceeds a preselected threshold.

Abstract: A system for light-tight handling of a supply of media between a supply station, a workstation and a collecting station, comprises a media handling apparatus defined by a frame and a housing enclosing an internal confine. Within this confine are a supply station and a collecting station disposed at opposite ends of the frame. A positioning drive is suspended above the supply and collecting stations to move media between the supply, collecting and work stations. A lifting shoe is provided as part of the positioning drive and includes a flexible material handling sheet which assumes a first and a second given radius when respectively energized and reverse energized to engage the media supported in curved form. Also, supply and collecting cassettes are provided with a tambour coverings for respectively automatically uncovering and covering the supported media while still maintained in the light-tight confines of the housing.

Abstract: A media handling unit is a selfcontained device which is capable of being moved to existing photoplotting structures to transport media sheets from a supply cassette housed within the unit and advanced into the plotter for conducting a plotting operation. The unit also retreives the scanned media from the photoplotter returning it the unit in a light tight environment where the scanned film is deposited onto a collecting tray. The supply of film is provided in a cassette having a semi-cyldrical support surface causing the film to take on a preformed configuration which is generally coincident with the shape of the support surface on the plotter.