Abstract: A temperature regulation system for a lithographic press, usually of the type using a waterless plate, used to control ink temperature at application to a substrate to be printed. The system includes a contactless sensor for sensing ink temperature between the ink distribution system and application to a substrate and for operating a temperature regulation system that controls the temperature of regulatable rolls in the ink path and thus the sensed ink temperature. This regulation system includes a refrigeration circuit, a secondary heater circuit for obtaining hot fluid, a reservoir for cold fluid and a mixing valve. This system is energy efficient, variable and responsive. It has been found that using this system the ink temperature can be very accurately controlled. Usually the system is used with a waterless plate and it has been found that commercially available lithographic inks as well as the special waterless inks can be used.

Abstract: An infrared dryer is provided for a printing press which uses a series of carriers, each comprising one or more gripper bars, on a conveyor to respectively carry printed sheets past the dryer. The sensor produces different binary signals in response to the presence or absence of material, viz, a gripper bar structure or carried sheets in the path, each carrier producing a predetermined number of transitions between the presence and absence signals, the only change between an empty carrier and one carrying a sheet being the duration of the presence and absence signals. A microprocessor is programmed to cyclically count from zero to the predetermined number of transitions, with each count cycle representing the passage of a carrier. The microprocessor also measures and compares the total durations of the presence and absence signals during each count cycle. If the presence signal duration exceeds the absence signal duration, then the heater is actuated to a preselected operating intensity.

Abstract: A powder metering device for distributing powder which is stored in a hopper, the powder then being delivered by the device to distributing nozzles. The metering device comprises a roller defining an engraved periphery which receives powder from the hopper. The roller carries powder at a controlled rate to a passage where the powder is then moved with the fluid to the distributing nozzles. The chamber holding the roller is maintained under positive pressure. Gaskets are located on opposite sides of the roller and maintained by the chamber pressure against the roll side walls and in engagement with the chamber walls. These gaskets, as well as the positive pressure conditions serve to discourage seepage of powder away from the path between the hopper outlet and the passage leading to the distributing nozzles.

Abstract: A system for distributing powder which is stored in a hopper and delivered from the hopper to distributing nozzles. A metering construction is interposed between the hopper and the distributing nozzles, this construction comprising a roller which receives powder from the hopper. The roller carries powder at a controlled rate to a passage where the powder is exposed to a pressurized fluid such as air. The powder is moved with the fluid to the distributing nozzles. Separate inlets, preferably for the introduction of air at atmospheric pressure, communicate with the passage. The distributing nozzles are designed for the distribution of the powder evenly over wide sheets of paper, foil or plastic, and over the printed surfaces of a web of paper or plastic.