Abstract: The object of the invention is to enhance precision in bonding the heating board and the radiating plate of a thermal print head, in the thermal print head A composed by attaching the heating board 2 on the surface of which a heating resistor for printing 4 is formed on the upper surface of the radiating plate 1, an identification mark M that functions as a positioning reference when the heating board 2 is attached on the radiating plate 1 is provided on the heating board 2 at a fixed interval from the heating resistor 4 and in addition, the identification mark M has a vertical side M1 equivalent to a positioning reference line D perpendicular to a direction in which the heating resistor of the heating board 2 is arranged (the direction of the x-axis).

Abstract: A heater comprises an insulating substrate which carries a parallel pair of conductor strips. The respective conductor strips are spaced from each other transversely thereof but electrically connected to each other by a plurality of heating resistors which are spaced longitudinally of the respective conductor strips. Advantageously, the heating resistors are arranged or configured so that the heater will have a temperature distribution which is equalized longitudinally.

Abstract: A linear heater comprises an insulating substrate, at least one resistor strip formed on the substrate, insulating edge members formed on the substrate to extend along the respective longitudinal margins of the resistor strip in contact therewith, and a heat-resistant protective coating formed on the substrate for covering the resistor strip and the respective edge members. The respective edge members, which themselves provide an insulating function, compensate for a thickness reduction of the protective coating at positions corresponding to the longitudinal margins of the resistor strip.

Abstract: A heater for a sheet material comprises an insulating substrate, and a plurality of heating resistor strips formed on the substrate to extend in parallel to each other between first and second common electrodes. At least one of the resistor strips is electrically connected to both of the first and second common electrodes while at least another of the resistor strips is electrically separated from the first common electrode.

Abstract: A linear heater comprises an insulating substrate, at least one resistor strip formed on the substrate, and a heat-resistant protective coating formed on the substrate for covering the resistor strip. The resistor strip has a double-layer structure which includes a first resistor layer formed directly on the substrate, and a second resistor layer formed on the first resistor layer. The first resistor layer has a pair of upwardly bulging longitudinal margins, whereas the second resistor layer is formed between the pair of upwardly bulging longitudinal margins of the first resistor layer to provide a substantially flat surface.

Abstract: A heater for a sheet material comprises an insulating substrate and a main resistor strip formed on the substrate. The substrate is further formed with auxiliary resistor strips adjacent to both ends of the main resistor strip. In operation, the main and auxiliary resistor strips are actuated simultaneously for heat generation. As a result, the additional heat generated by the auxiliary resistor strips compensates for higher heat dissipation at both ends of the heater, thereby equalizing the temperature distribution longitudinally of the heater.

Abstract: A heater for heating a moving sheet material by contact therewith is used, for example, in electrophotographic apparatus for fixing toner to printing paper. The heater comprises an insulating substrate formed with a striplike heating element on its upper surface, and a support plate for supporting the substrate. A higher heat preserving property is given to the opposite end portions of the heating element than to a longitudinal intermediate portion thereof to thereby compensate for a temperature reduction at the element end portions and make the heating element uniform in temperature over the entire length thereof.

Abstract: A heater for heating a sheet material along a standard contact line comprises an insulating substrate, and a heating resistor strip formed on a surface of the substrate to extend longitudinally thereof. The resistor strip has an intermediate portion which is located transversely offset from the standard contact line, and a pair of end portions located at least partially at the standard contact line.

Abstract: A heater comprises an insulating substrate which carries a pair of transversely conductor strips, a resistor line extending between the respective conductor strips. The respective conductor strips are connected to the resistor line by electrode teeth spaced longitudinally of the main resistor line and arranged in staggered relation on both sides of the resistor line.

Abstract: A method is provided for making unit heads from a material head. The unit heads are used to constitute a divisional-type thermal head. The material head includes an elongate insulating substrate carrying a longitudinal array of heating dot portions, and a protective layer extending longitudinally of the material head to cover the array of heat dot portions. According to the method, the material head is cut along at least one cutting line which extends transversely of the material head at a position between two adjacent heating dot portions, wherein the protective layer has cutouts which extend from the respective longitudinal edges of the protective layer toward the array of heating dot portions at the position of the cutting line.