Ricoh Company, Ltd.

Nobuo Mochizuki

Akira Suzuki

Kunichika Morohoshi

Hajime Oyama

Mitsuru Hashimoto

Teruyuki Ohnuma

Motoo Tasaka

Hiromi Demizu

Hideo Watanabe

Seiichi Miyakawa

Keishi Kubo

Toshiyuki Kawanishi

Susumu Tatsumi

Yukio Tabata

Tadahiro Eda

Yukihiko Nakagawa

A multicolor thermosensitive image transfer sheet comprising (i) a substrate and (ii) a plurality of thermofusible ink layers, formed thereon side by side, each thermofusible ink layer comprising a thermofusible ink component having a different color and a different surface tension from the colors and surface tensions of the ink components in the other thermofusible ink layers, and a multicolor thermosensitive image transfer recording method of obtaining multicolored images by transferring imagewise the thermofusible ink layers of the multicolor thermosensitive image transfer recording medium to a receiving sheet in the sequential order from the highest to the lowest, or from the lowest to the highest, critical surface tension of the thermofusible ink components are provided.

Multicolor thermosensitive image transfer sheet and recording method

Multicolor thermosensitive image transfer sheet

A thermosensitive image transfer recording medium comprising a support material; an image transfer layer formed on the support material, comprising a fine porous network structure made of a resin comprising cellulose acetate butyrate; a non-volatile oily material which is contained in the fine porous network structure, and which does not dissolve the resin of the fine porous network structure; and a thermofusible ink composition which is held in the fine porous network structure, comprising (a) a thermofusible wax material is solid at room temperature, and (b) a colorant.

Thermosensitive image transfer recording medium

A thermosensitive image transfer recording medium comprising a support material and a thermofusible ink layer formed thereon, comprising an image gradation control agent, a coloring agent and a carrier material for holding the coloring agent at normal temperatures and to carry the coloring agent, upon application of heat, out of said thermofusible ink layer for image formation, all of which are contained in a fine porous resin structure.

A thermosensitive image transfer recording medium comprising a support material and a thermofusible ink layer formed thereon, which thermofusible ink layer comprises a dye component, a binder agent and a pigment having a needle-like crystal form, which is dispersed in a network form throughout the thermofusible ink layer.

An apparatus for developing a latent electrostatic image formed on a photoconductive recording material in a dry type electrophotographic copying machine typically employing a one-component type developer comprises a conductive electrode held in contact with the developer. The electrode is connected to a power source through a switching device and serves to charge the developer to a predetermined polarity with a predetermined potential before the latent image is developed. In this way, the latent image can be developed selectively as either a normal image or a reverse image quite easily.

Development apparatus

A photoconductive drum or sheet is movable relative to a developing electrode which is biased to a voltage which prevents smearing of the background areas of the copy. A sensing electrode is disposed upstream of the developing electrode in the direction of movement of the drum or sheet which senses the voltage on the drum or sheet. The sensing electrode is provided in a plurality of independent segments, and a computing circuit selects the voltage on the segment which is lowest in magnitude and which corresponds to a background area of the copy and applies the biasing voltage to the developing electrode in dependence on the sensed voltage. An auxiliary electrode is provided so that the combination of the sensing electrode and the auxiliary electrode is coextensive with the drum or sheet in a direction perpendicular to the movement thereof to prevent streaking of the copy. The auxiliary electrode is either electrically floated and thereby self-biased by the drum or sheet or the biasing voltage from the computing circuit is applied thereto.

Developing electrode arrangement for electrophotographic apparatus

A development apparatus for use with dry type copying apparatus having: a development roller, which is rotated in close proximity to a latent electrostatic image bearing recording material; a hopper for supplying an insulating toner onto the development roller; and a single developer regulating member in the form of a blade having an acute angle tip disposed at the edge of or right behind the outlet of the hopper in such manner that the top surface of the member forms an acute angle with the downstream side in the direction of development roller rotation of a tangent to the development roller at a point right under the tip of the development regulating member. Alternatively a single or a plurality of triboelectric charging members may be disposed at the edge of or right behind the outlet of the hopper of the respective angles with the top surfaces of the blades with respect to the respective tangents to the points on the surface of the development roller right under the respective tips varying from an acute angle to an obtuse angle in the direction of development roller rotation.

Toner charging apparatus

An apparatus for developing an electrostatic image on a photosensitive member or on a record member using one-component developer is provided. The developer comprises a magnetic toner or non-magnetic toner having a volumetric resistivity of not less than 10.sup.6 .OMEGA.cm. The apparatus comprises a developing roller at least the surface portion of which is formed of elastic rubber, means for supplying toner to the surface of the developing roller, and means for charging the toner on the developing roller to a given polarity. The developing roller is driven for rotation at a peripheral speed which is equal to or greater than the speed of movement of the image carrying member. Additionally, the apparatus includes levelling means for levelling the toner on the developing roller, charge neutralizing means for eliminating the electric charge from the toner after the developing step, and scraper means for stirring the toner after the developing step. Various modifications and limitations of the means and members mentioned are possible.

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Shizuoka, Japan

Nobuo Mochizuki