Abstract: A plate loader for an offset printing machine includes means for allowing the loader to be pivoted between an operative position in which drive is automatically connected to the plate forwarding means of the plate loader, and a raised inoperative position in which drive is automatically disconnected from the plate forwarding means to allow plates to be fed by hand. The printing machine also includes an applicator for plate priming liquid, where the applicator is mounted movably on the machine frame for adjustment of the spacing between the plate delivery mechanism of the applicator and a stop position for the leading edge of a plate on the plate loader, in order to adjust for different plate lengths.

Abstract: The disclosure relates to a stencil duplicator having a loading device in the form of a pair of guide members which are mounted for movement between a first position in which they define a slot into which a stencil can readily be inserted to attain a predetermined position and a second position in which they define a narrower slot and hold the stencil heading strip close to the surface of the rotatable ink screen of the duplicator and in the path of movement of mounting pins carried by the stencil mounting bar on the ink screen so that when the pins next pass the guide members they enter holes in the stiff heading strip of the stencil and drag the stencil through the slot and onto the surface of the ink screen without any need to stop the machine.Preferably the guide members present elongate edge portions which are undulated to define recesses, through which in the second position of the guide members the pins may pass, and fingers between said recesses to hold the stencil heading strip adjacent each recess.

Abstract: Pressure-sensitive duplicating stencils comprise an impregnated sheet of stencil tissue strippably attached by a laminating coating to a backing sheet, which is removed during use of the imaged stencil.

Abstract: Planographic printing plates for use without fountain solution, and especially suitable for imaging with an electrophotographic toner, have a surface containing a fluorinated polyurethane. In use only the image areas accept ink.

Abstract: The invention provides a novel ink for dry planographic printing. The new ink is based on a vehicle containing the reaction product of an oil-modified alkyd resin, a rosin-modified phenolic resin, and a diisocyanate and also a high viscosity silicone oil. The new ink can be used with planographic plates having an oleophobic surface and does not adhere to the non-image areas.

Abstract: A stencil duplicator includes stencil ejection apparatus including a mechanism to release the clamp for the stencil head, a guide to lead the head, as the duplicator rotates, to drive members which forward the used stencil into a container in which it is folded or creased so as to be foreshortened and stored with other stencils in a small space prior to disposal.

Abstract: For the purposes of removing a used stencil or an ink screen from the cylinder(s) of a duplicator, a rotatable core alongside the duplicator cylinder is driveable by a drive transmission from the main duplicator drive, by way of a freewheel clutch such that the core is driven only when the duplicator cylinder is rotated in the reverse direction as compared with the normal direction of rotation during printing, and also by way of a friction-slip connection arranged such that with no slip the peripheral speed of the core is higher than that of the duplicator cylinder along which it is mounted.

Abstract: A device for rolling up onto a core a stencil or ink screen being removed from a duplicator, in which means alongside the or a duplicator cylinder for supporting a core and for driving it at a peripheral speed in excess of the peripheral speed of the duplicator so that a stencil or ink screen from the duplicator may be unrolled from the cylinder and onto the core with tension in the stencil or ink screen maintained by virtue of slipping drive to the core.

Abstract: A stencil duplicator has a rotatable support which, in use, supports a stencil, and a feed path along which a stencil is advanced as it is loaded onto the support defined by a supporting roller spaced from the rotatable support and a smoothly arcuate guide surface extending over a considerable part of the feed path between the roller and the support. The arrangement is such that as a stencil, whose trailing part is supported by the supporting roller, is wound onto the rotatable support, it is drawn over the guide surface.

Abstract: A sheet feed mechanism for feeding individual sheets from a stack thereof comprises a first generally horizontal surface for supporting the edge of a stack of sheets and a second surface for supporting a face of the stack, the second support surface being provided by a plate member supported above the first surface and inclined at an obtuse angle with respect thereto. The plate member is supported so that the second surface is urged towards the nip defined between the first support surface and a sheet feed roller in such a manner that as the second surface approaches the nip the obtuse angle increases. In a preferred embodiment a cam surface is provided on the plate member to adjust the rate at which the obtuse angle varies as the second surface approaches the nip. The preferred embodiment also includes means for adjusting the height of the nip defined between the sheet feed roller and the first support surface to permit feeding of different gauges of sheets.

Abstract: A device for rolling up onto a core a stencil or ink screen being removed from a duplicator, in which a pair of rotatable core holding members is located adjacent the or a duplicator cylinder and at least one of the members is driveable from the cylinder by means of a drive wheel carried on a pivotable lever.