Abstract: A printing plate holding device for an offset duplicator. The device includes a base slidably positioned on one side of a grooved portion of a plate cylinder of the duplicator. A clamp plate is secured to the base and a clamp lever is attached to the clamp plate. A latch is loosely secured to a pin attached to the clamp lever and connected to a spring to provide a plate clamping force upon the clamp plate. A guide plate and a plate release preventing plate are attached to an outer longitudinal side of the base. An axial displacement control device is positioned at one longitudinal end of the cylinder while a circumferential displacement control device is positioned at the other longitudinal end thereof.

Abstract: A packing sheet overlaying device for offset printing in which a packing sheet can readily be attached to and released from a cylinder of an offset printing machine or the like. The packing sheet is held in position at one end by a gripper which is attached to a bracket which is rotatably mounted on a cam lever shaft. A slot is formed in the bracket and a screw passes through the slot to secure the bracket to the cylinder to lock the packing sheet in place. When it is desired to change the packing sheet, the screw is loosened and the bracket rotated through an angle defined by the length of the slot to thereby form a gap between the gripper and the corresponding edge of the cylinder. The other end of the packing sheet is held in position by a tensioning mechanism including a tensioning knob provided to adjust the tension on the packing sheet.

Abstract: An image detecting and positioning device for an off-set printing machine capable of printing on both sides of a printing sheet. Electromagnetic clutches couple and disengage gears from the shafts of rubber cylinders in response to input signals with the two gears engaged with each other. Electromagnetic brakes are also coupled to the shafts of the rubber cylinders. Rotational angle detectors provide outputs related to the rotational positions of the shafts of one of the rubber cylinders and its plate cylinder. The electromagnetic brakes and clutches are operated in response to outputs from the rotational angle detectors to correctly position images on the rubber cylinders.

Abstract: An offset printing machine including an impression cylinder cleaning device which is laterally positioned and removed from a location below the impression cylinder of the machine. The cleaning includes a cleaning mechanism, a window and supports in the main frame of the printing machine, and a cleaning mechanism positioning device provided on the main frame. The cleaning mechanism includes a cleaning tank and a group of rollers including a cleaning roller coupled to auxiliary frames which are rotatably supported between main frames of the cleaning mechanism. A plurality of guide bars extend from a position below the window in the printing machine frame. The cleaning mechanism positioning device brings the cleaning mechanism into the proper position below the impression cylinder once the cleaning mechanism is inserted through the window.

Abstract: An automatic plate supplying device for supplying plates to an offset printing machine is disclosed, which operates to sequentially supply original plates to an original plate conveying device adapted to feed original plates to a plate cylinder provided in the printing machine. A pivotable suction means removes plates from the bottom of a stack for delivery to the machine.

Abstract: New blanket cleaning liquid flows from an inverted bottle 16 inserted through a hole 7 in the upper arm 8 of a U-shaped bracket 5 to a cleaning bath 2 via a spring biased push valve 20 in the bottle, a supply pool 9 in the lower arm of the bracket beneath the pouring mouth of the installed bottle, and a three-way control valve A. The latter may selectively communicate the supply pool with the cleaning bath in a delivery mode, or communicate the bath with a used liquid storage bottle 28 in a discharge mode. The bath is vertically disposed at a position proximate that of the bracket, whereby the liquid level in the bath is automatically maintained at the same level as the new cleaning liquid in the supply pool, which in turn is maintained at the height of the pouring mouth lip of the bottle 16.

Abstract: A pressure control device for offset printing machines, having a cam shaft mounted between a pair of side plates, a dial provided at one end of the shaft, cam plates rotating with the dial in a single body having spiral cam slot surfaces. The cam slots are engaged with pins mounted on two arms supporting a pressure cylinder, and have one end formed to latch the pin in an escape position. With the above device, even during the operation of a printing machine, the pressure of the pressure cylinder to printing paper can be adjusted simply by the dial control, and an automatic adjustment can further be possible when the dial is set at AUTO position and the pins are in the escape positions.

Abstract: A mechanism which has a first cam plate pivotally mounted on an operating shaft having an operating lever joined thereto and a second cam plate pivotally mounted on an eccentric shaft of a master cylinder and moved with an arm fixed to the operating shaft. The first cam plate is formed with a pump switch cam, a set cam for operating the operating lever stepwise and a paper feed control cam. The second cam plate is formed with a form roller-separating cam and a master cylinder-separating cam. The form roller-separating cam causes press contact between a form roller and the master cylinder when the operating lever is set at the I position. When the operating lever is set at II, the master cylinder-separating cam forces the master cylinder to maintain its contact with a blanket cylinder, and when the operating lever is set at IV, the paper feed control cam allows a suction foot to move down to start paper feed through an auxiliary operating lever.