Abstract: The apparatus for cutting semi-rigid sheets one by one, in particular corrugated cardboard sheets, comprises a cutting tool fixed on a tool-carrier plate, a backing cylinder, at least one independent motor having electronic servo-control and rotatable in either direction driving the tool-carrier plate in its reciprocating motion, and device for monitoring rotation of the backing cylinder and connected to a controlling electronic circuit provided with an input for receiving operating parameters including at least the length l of the cutting tool. The electronic circuit is programmed so that the amplitude of the reciprocating motion is a function of the parameter l and so that the linear speed of the tool-carrier plate is constantly equal to the peripheral linear speed of the backing cylinder so long as the cutting tool is in contact with said backing cylinder.

Abstract: In the sheet-by-sheet printing process, a sheet is printed during its passage in the nip zone between a printing cylinder, which comprises on its periphery a rubber element, and an impression cylinder. The ink is supplied to the printing cylinder by an ink supply cylinder. In order to reduce the deformations of the printing dots, the ratios of the peripheral linear speeds of the ink supply cylinder and of the impression cylinder with respect to the peripheral linear speed of the rubber element of the printing cylinder are adjusted to values in the range of 1.004 to 1.05.

Abstract: The printing machine according to the invention comprises, for a given cylinder, first means for displacement from a first position corresponding to the work position to a second position, and second means for displacement from said second position to a third position; the shaft of said cylinder comprises an individual drive motor and toothed wheels at its two ends; the second displacement means comprise a set of two racks in which the toothed wheels may mesh, with the result that displacement of said cylinder from the second to the third position is obtained thanks to the rotation of the drive motor of the shaft of said cylinder. It may be question of a machine with automatic change of ink rollers, with at least two double-displacement ink rollers, or of a machine with automatic washing of the plate cylinder, with a double-displacement impression cylinder.

Abstract: This invention relates to a device for distributing semi-rigid sheets, one by one, below or above a stop behind which said sheets are stacked. The device has no sheet-extraction system in front of the stop and no fixed surface in contact with the stack in the proximity of the stop. It comprises at least three cylinders adapted to entrain by friction the sheet with which they are in contact, the axis of the outlet cylinder being vertical with respect to the stop. Moreover, it comprises a device for synchronizing the cylinders so that, during distribution of a given sheet, on the one hand, each of the cylinders upstream of the outlet cylinder is decelerated after the sheet has left contact therewith and, on the other hand, the outlet cylinder is decelerated after the rear edge of the sheet has substantially gone beyond the vertical with respect to the stop, the cylinders upstream already being in stopped position.

Abstract: The sheet feed print installation of the flexographic type for printing on a semi-rigid material of the corrugated card type comprises:a plate-carrier cylinder having a plate of thickness E.sub.c fixed to the periphery thereof;a backing system, optionally constituted by a backing cylinder;a screened cylinder; anda transfer system having an inlet into which the sheets are inserted one by one.The installation further comprises:a) three or four motors which are mechanically independent, the first rotating the plate-carrier cylinder, the second rotating the screened cylinder, the third rotating the transfer system, and optionally the fourth rotating the backing cylinder; andb) an electronic circuit connected to the second, third, and optionally fourth motors, that receives an input reference signal and that includes means for inputting operating parameters, including at least the thickness E.sub.c of the plates and the print rate.

Abstract: The invention relates to a process and to an apparatus for transferring a sheet of material. The process is characterized in that:at least two successive conveyors (11, 12) are connected, the second conveyor having a coefficient of adhesion which is higher than the first conveyor, andfirst, the speeds of said conveyors are adapted to the speed (V.sub.2) prevailing on the sheet as it arrives on the first conveyors, and then,when the sheet covers the second conveyor with a portion deemed adequate, the speed of the second conveyor is modified until it attains the speed (V.sub.2) at which the second conveyor is to deliver the sheet, and,finally, as soon as the sheet has let the second conveyor, the speed of the second conveyor is brought back to that of the first. The method and the apparatus for carrying out the method have particular application to printing and cutting machines.

Abstract: The invention relates to a guide stop for positioning sheet products. It is characterized by the fact that the stop guide is made up of a series of thin strips (9, 10) which, on the one hand, are substantially parallel to each other and, on the other, normal both to the plane P of the sheet (6) and to the corresponding edge (4 or 5) of said sheet (6) which the stop guide (2 or 3) is to position. The invention is used for positioning sheets of paper or cardboard in feed tables, printing or cutting presses or stacking machines.

Abstract: The invention relates to a device for fixing a plate on a cylinder, while permitting to quickly control, at certain instants, the application and fixation of this plate on a particular angular portion of this cylinder and, at other instants, the disengagement of this plate.It is characterized by the fact that, in addition to means (9) enabling the plate (3) to be brought against the cylinder or, on the contrary, separating it from its area of support, it comprises means (10) for fully applying on the cylinder both the median portion and the ends of the plate.Application to the mechanical construction industry and, more particularly, to rotary printing and cutting machines.