Riso Kagaku Corporation

Kengo Sugaya

Terutoshi Nakao

Kenji Yamada

Tetsu Yamanaka

Katsumi Kuriyama

Syouichi Ikezima

An oily inkjet ink comprises a pigment, a dispersant, and an organic solvent. The organic solvent contains an ester solvent and/or an alcohol solvent. A containing quantity of a water-soluble ingredient in the pigment is equal to at most 0.15% by mass.

Oily inkjet ink

A protective layer of a thermal head is treated with a surface-treating agent containing a chlorosilyl group-containing compound and a fluoroalkyl group-containing silane compound to form a water-repellent oil-repellent dry film thereon. Both compounds are dissolved or suspended into an organic solvent such is an alcohol solvent. The solvent can contain 0 to 10 wt % of water based on the total weight of the solvent. The surface-treating agent may have a pH of 0 to 3, and both compounds are contained in an amount of 0.01 to 10 wt % in total based on the total amount of the treating agent. The treatment lowers the surface tension of the protective layer and thus prevents deposition of melt on the thermal head for a long period of time while maintaining thermal conduction and surface smoothness of the thermal head.

Thermal head, surface-treating method therefor and surface-treating agent therefor

A thermal head is provided which comprises an insulation substrate, a heat-generating resistor on the insulation substrate, a conductive layer for supplying electric power thereto, and a protective layer provided thereon. In the thermal head, the protective layer is surface-treated with a water- and oil-repellent and heat-resistant organosilicon-containing compound to provide a contact angle with respect to water of 95 degrees or more. The organosilicon-containing compound is preferably a fluoroalkyl silane with a fluorinated carbon chain length of 6 to 10 carbon atoms, having a hydrolyzable reactive group at a terminal thereof. The compound is strongly bonded to the protective layer via a silanol group by heat-treatment at 50&deg; C. or more. The protective layer surface may be properly pretreated with an organosilicon compound having an isocyanate group bonded to a silicon atom.

Method for treating the surface of thermal printing heads

In a cylindrical drum 1 for stencil printing which consists of a porous cylindrical plate 2 and a screen layer 3, in which a stencil sheet is attached to the outer surface of the screen layer having an ink permeability, an ink is supplied from the inner surface of the porous cylindrical body which rotates around its own central axis, the present invention provides a screen layer consisting of a woven fabric of conjugated fibers of a sheath-and-core or a side-by-side type consisting of a lower melting component and a higher melting component and making the intersections of the fibers fixed together through the melt-adhesion of the lower melting point component by means of thermocompression bonding.

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Ibaraki-ken, Japan

Kengo Sugaya