Abstract: A multi-color thermal transfer recorder has a thermal recording head, a roll disposed opposite to the thermal recording head, and an ink donor sheet having two or more layers of single-color ink different in color from each other, the length of each ink layer being equal to the length of the outer circumference of the opposing roll.

Abstract: A heat-sensitive recording head having heat generating elements arranged on an insulating substrate and a system for preheating said substrate and controlling the heat generated during the recording operation. In one embodiment the substrate is placed in contact with a larger heat sink which is heated by a carbon-type internal resistor, a printed circuit contacting resistor, or a conventional heater. A thermal sensor detects the temperature of the heat sink and is fed to controls for controlling the overall application of heat. In another embodiment the substrate is placed in contact with a Peltier effect device which controls heat generation and absorption.

Abstract: A plurality of thermal head assemblies can be arranged around a single backing roller to minimize the distance between recording stations. Synchronization marks recorded on the paper at a first station can be detected between recording stations to control the timing of image recording at the later stations.

Abstract: A heat-sensitive recording head including an insulating substrate, an array of heat generating elements, a plurality of leads alternately arranged on both sides of the array of heat generating elements on the insulating substrate with the heat generating elements interposed between the leads. Lead wires are connected to predetermined ones of the leads either directly or through diodes. The lead wires are arranged in a matrix format and heat generating elements are coupled in blocks with the number of blocks being equal to half the number of common drive terminals provided. With the number of blocks represented by n, the average value of the resistances of the heat generating elements by r, and the maximum variation of the resistances by .+-.r, ##EQU1## is established.

Abstract: A centrifugal separator comprises a centrifugation chamber, gas inlet ports for introducing a gas into the centrifugation chamber so as to whirl the gas, a clean gas discharge pipe provided on the upper portion of the centrifugation chamber, and a guide member secured to the lower portion of the centrifugation chamber. The guide member has an annular groove, outer fine holes made in the groove, a guide portion projecting conically inward the centrifugation chamber, and an inner hole made in the center of the guide portion. A gas including particles is introduced into the centrifugation chamber, in which the particles are separated. The separated particles are trapped in the groove with gas, then discharged from the outer holes. The clean gas removed of the particles is guided by the guide member to direct to the gas discharge pipe, at the same time the particles with gas toward the guide member also are guided by the guide member to be subjected to the centrifugal force.

Abstract: A drive device for a heat sensitive recording head in which the heat generating elements in an entire array generate heat uniformly. The heat generating elements within an array-type heat sensitive recording head are separated into groups. Voltage dropping elements connect the various heat generating elements to common terminals, one of which is provided for each group. The voltage drops provided by the various voltage dropping elements are adjusted such that the heat generating elements produce heat uniformly so that the image recorded is uniform over the entire recording surface.

Abstract: In a film conveyor for use in developing films comprising a first and a second belt racks consisting of a plurality of narrow belts and pressure rollers, and a roller rack consisting of a plurality of squeegee rollers and spray tubes arranged between said two belt racks, the pressure rollers of the two belt racks are so positioned as to press the belts at the mid points of two vertically adjacent squeegee rollers, and the squeegee rollers of the roller rack are arranged in two vertical rows between which an adequate number of said spray tubes are horizontally disposed so that developing solution may be sprayed out directly toward between said two rows of squeegee rollers. Further, the squeegee rollers of the roller rack are driven in synchronism with the moving speed of the belts so as to effect smooth conveyance of the film held between the belts and the squeegee rollers.