Fuji Photo Film Company, Limited

Junichi Yoneda

Makoto Kashiwaya

Taihei Noshita

Akira Igarashi

Kensuke Ikeda

Hirofumi Mitsuo

The invention provides an improved thermal head having a protective film of a heater which comprises a carbon-based protective layer having a hardness difference in its thickness direction. The invention also provides an improved method of manufacturing the thermal head. A thermal head is thus obtained having a protective layer which is significantly protected from corrosion and wear, also from cracks and peeling-off due to heat and mechanical impact, and which allows the thermal head to have a sufficient durability to exhibit a high reliability over an extended period of time, thereby ensuring that the thermal recording of high-quality images is performed consistently over an extended period of operation.

Thermal head and method of manufacturing the same

There is provided a thermal head having a protective film including a carbon-based protective layer and a lower insulating protective layer which is composed of one or more sub-layers and formed below the carbon-based protective layer, wherein at least one of the sub-layers of the lower protective layer contains not more than 5 atm % of oxygen. The protective layer has significantly reduced corrosion and wear and is protected from cracking and peeling, whereupon the thermal head obtained can have a sufficient durability to ensure that high reliability is exhibited over an extended period of time to perform thermal recording of high-quality images consistently over an extended period of operation.

Thermal head

The improved thermal head of the invention is the one having a protective film of a heater formed on the heater, the protective film comprising a ceramic-based lower protective layer composed of at least one sub-layer and a carbon-based upper protective layer formed on the lower protective layer, wherein a surface of the lower protective layer on which the upper protective layer is to be formed has a surface roughness value Ra of 0.005 to 0.5 &mgr;m; or the one in which the depth of a depression step which may be formed on the surface of the lower protective layer due to the thickness of the electrodes used for supplying power to the heater (or heat-generating resistor) was reduced to 0.2 &mgr;m or less. Therefore, the thermal head of the invention has a protective film which has significantly reduced corrosion and wear, which is advantageously protected from cracks and peeling-off due to heat and mechanical impact and which allows the thermal head to have a sufficient durability to exhibit high reliability over an extended period of time, thereby ensuring that the thermal recording of high-quality images is consistently performed over an extended period of operation.

The improved thermal head has a protective film of a heater formed on the heater, the protective film comprising a ceramic-based lower protective layer composed of at least one sub-layer, an intermediate protective layer also composed of at least one sub-layer and formed on the lower protective layer, and a carbon-based upper protective layer formed on the intermediate protective layer. The thermal head of the invention has a protective film which has significantly reduced corrosion and wear, which is advantageously protected from cracking and peeling due to heat and mechanical impact and which allows the thermal head to have a sufficient durability to ensure that the thermal recording of high-quality images is consistently performed over an extended period of operation.

The thermal head having a protective film of a heating element, the protective film comprising at least one protective layer including a carbon-based carbon protective layer, wherein an oxygen amount in an interface between the carbon protective layer and a lower layer formed under the carbon protective layer is not more than 20 atm %. The thermal head includes a protective film which has significantly reduced corrosion and wear, which is free from cracking and peeling due to heat and mechanical impact and which allows the thermal head to have sufficient durability to ensure that the thermal recording of high-quality images is consistently performed over an extended period of time. Even for an application in which recording under high-energy and high-pressure conditions is performed on a thermal film using a high rigid substrate to be employed in the medical use and the like, the thermal head also has sufficient durability to exhibit high reliability over an extended period of time.

The improved thermal recording system uses both a thermal head having a layer to protect heaters and a thermal recording material in which a thermal recording layer unit has a water content of no more than 6 wt. %, the protective layer of the thermal head comprising at least one ceramic-based lower sub-layer which is overlaid with a carbon-based upper sub-layer. This thermal recording system improves the wear resistance and electrical insulation of the protective layer on the thermal head so markedly that high operational reliability is insured for an extended period of time.

Thermal recording system including thermal head and thermal recording

The improved thermal head of the invention is the one having a protective film of a heater formed on the heater, the protective film comprising a ceramic-based lower protective layer composed of at least one sub-layer and a carbon-based upper protective layer formed on the lower protective layer, wherein a surface of the lower protective layer on which the upper protective layer is to be formed has a surface roughness value Ra of 0.005 to 0.5 .mu.m; or the one in which the depth of a depression step which may be formed on the surface of the lower protective layer due to the thickness of the electrodes used for supplying power to the heater (or heat-generating resistor) was reduced to 0.2 .mu.m or less. Therefore, the thermal head of the invention has a protective film which has significantly reduced corrosion and wear, which is advantageously protected from cracks and peeling-off due to heat and mechanical impact and which allows the thermal head to have a sufficient durability to exhibit high reliability over an extended period of time, thereby ensuring that the thermal recording of high-quality images is consistently performed over an extended period of operation.

Thermal head method of manufacturing the same

The improved thermal head comprises heating elements which were provided with heating histories to previously change their resistance values by predetermined values; and a carbon-based protective layer which was formed after the heating elements were provided with the heating histories. The invention provides the thermal head in which corrosion and wear of the protective film, and the resistance variation of the heating elements due to thermal recording were significantly reduced, and which has a sufficient durability and stability with the passage of time to perform thermal recording of high-quality images in a consistent manner over an extended period of operation.

According to the improved method of thermal recording with a thermal head, each time a specified amount of thermal recording has been performed, a coating layer is formed in a specified area of the surface of the protective layer on the glaze of the thermal head and, thereafter, the thermal recording operation is resumed. The improved thermal recording method and the improved thermal recording apparatus to which this method is applied permit a coating layer to be present at all times on the surface of the protective layer on the glaze of a thermal head; hence, a great number of prints can be produced without causing the wear and corrosion of the protective layer, thereby assuring that the thermal head is long-lived to maintain high operational reliability over a prolonged period.

Method and apparatus for thermal recording

A method for automatically feeding a heat-sensitive recording material in a heat-sensitive recording device, including storing the heat-sensitive recording material in a closed tray or magazine conditioned at a relative humidity of 35 to 85% and then feeding the heat-sensitive recording material. This method prevents deterioration of image quality due to environmental change (humidity change) and feeding troubles without enlarging the system.

Heat-sensitive recording material feeding method

A novel heat-sensitive recording material comprising a support having coated thereon a heat-sensitive coloring layer containing a colorless or light-colored electron donor dye precursor and an electron acceptor compound which colors upon reaction with said electron donor dye precursor and a protective alyer coated on the heat-sensitive coloring layer comprising a saponified product of a vinyl acetate-acrylamide copolymer or vinyl acetate-methacrylamide copolymer having an acrylamide or methacrylamide content of about 0.5 to about 80% by weight.

Heat-sensitive recording material

A heat-sensitive recording material is described, comprising a heat-sensitive recording layer containing an electron-donating colorless dye and an electron-accepting compound, said heat-sensitive layer being provided on a support member, and said heat-sensitive layer containing from 5 to 50% by weight, based on the total weight of the heat-sensitive layer-constituting components, of polymer particles having an average particle size of from 0.03 to 16 microns, selected from the group consisting of ethylene-.alpha.-olefin copolymer particles, low density polyethylene particles, and ethylene-vinyl acetate copolymer particles.

Growing community of inventors

Shizuoka, Japan

Junichi Yoneda