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: Device for the conveying of sheets from each of a plurality of sheet piles via a partially common conveyor track. This track extends in vertical direction along superposed stock holders. Adjacent to the sheet delivery side a driven roller is stationarily arranged above each pile. Each of these rollers can function both as suction roller for separating sheets from a pile and as friction roller for conveying sheets in the common track. For separating sheets from a pile, each pile can be brought by pneumatic means into short contact with a driven roller then functioning as a suction roller. For conveying sheets in the common track, each roller cooperates with a pressure roller. After a sheet in the common track has been gripped between a driven roller and a pressure roller, the sucting action of that driven roller is interrupted.

Abstract: A reproduction camera employed for the production of contact screen prints from an original is provided with a control system including a computer means which, after feeding in data representing the minimum and maximum optical densities of the original, the optical data of the screen used and the required data of the camera and the light sensitive material such as film, determines and applies a dosage for the main exposure and one or more additional exposures to yield a screened print of which the highlight dots and the shadow dots have specific sizes correspondingly substantially completely to the minimum and maximum optical densities of the original. The computer means includes an adjustable basic screen range regulator for varying the main exposure at the time of the adaption of at least one of the additional exposures in order to continue to reproduce substantially completely the minimum and maximum optical densities of the original with the specific dot sizes.

Abstract: An optical apparatus for setting any one of a plurality of lenses in a certain operating position and for setting the opening of at least one of the lenses comprises a lens turret rotatable around an axis and having the lenses mounted thereon at locations spaced apart about the same axis, a gear on at least one of the lenses and turnable relative to the turret for adjusting the lens opening, and a drive system including a shaft coaxial with and rotatable in either direction about the axis and carrying a drive gear engaging each adjusting gear for turning the lens turret and each adjusting gear. At least one of the adjusting gears has a limited range of rotation relative to the lens turret in at least one direction so that the turret is rotatable by the drive gear through an adjusting gear when the latter is at a limit of its range of relative rotation. Preferably each lens is provided with an adjusting gear and only one drive gear is employed, which at any moment drivably engages all the adjusting gears.