Fuji Xerox Co., Ltd.

Fuji Kagakushi Kogyo Co., Ltd.

Haruhiko Moriguchi

Takashi Ohmori

Toshiharu Inui

Yoshiki Kikuchi

Fujio Moriguchi

Masami Kurata

Tomio Murayama

Masayuki Hisatake

Takashi Omori

Akio Noguchi

Svay Leng

Norihiko Koizumi

Hiroyuki Saitoh

Yoshikazu Shimazaki

Tadao Seto

Hisao Nakajima

Tadashi Yamamoto

Katsuo Makino

Leng Svay

Yoshihiro Ishida

Yasuo Katoh

Inui Toshiharu

Hiromitsu Matsuba

The likelihood that differently colored inks will overlap is minimized in a multicolor printing system employing the dither method by using a different dither matrix for each color and arranging the lowest threshold valued cells of the dither matrices so that they do not overlap when repeated across a printing surface. A preferred embodiment uses rectangular dither matrices of different size, shape, and arrangement of threshold values.

Multicolor printing method using rectangular dither matrices of

In a half-tone recording method and apparatus, half-tone expressing units, each consisting of several recording picture elements, express gradations of density in a document. The recording picture elements in the units are assigned various half-tone levels with the half tone level of at least one of the recording picture elements both increasing and decreasing as the gradation of the half-tone expressing unit increases.

Tone reproduction method and apparatus

A heat storage correction apparatus and method determines the degree of solidity of a picture data to be recorded and increases the quantity of energy supplied to data elements recording substantially solid portions of the picture elements.

Heat storage correction apparatus

Each picture element is made to correspond to a plurality of dots and the ratios of printing energy corresponding to respective dots in each picture element are determined to correspond to respective tones. The heat accumulation state of a heat generating member corresponding to a picture element to be printed is detected from the tones of picture elements about the picture element to be printed for controlling the printing energy supplied to the heat generating members corresponding to respective dots of the picture image to be printed in accordance with the printing energy ratio and the detected state. With this method it is possible to provide a half tone print having uniform high quality regardless of the tone of a previous line and tones of surrounding picture elements.

Method and apparatus for thermal half-tone printing

A printing method is shown in which printing quality is improved when superimposed thermal-transfer recording is performed. According to the present invention, at least one of a plurality of thermal-transfer media is made of a material of different thermal characteristics from the remaining media. Different thermal-transfer media thermal characteristics are obtained by changing the thickness, melting point or viscosity of the thermal-transfer ink on the thermal transfer media, or by changing the thickness, quality of material or density of the base material of the thermal-transfer media.

Printing method

A copier capable of producing both color images and monochrome images is disclosed, which comprises a platen for mounting thereon a manuscript, a scanner unit adapted to reciprocate relative to the platen and generate image signals divided in three primary colors by reading the manuscript for each line or for each set of a plurality of lines, four thermal heads for receiving image signals and, in response thereto, selectively actuating heat generation elements, means for supplying the thermal heads with ink donor films of four colors including black, and means for effecting thermal transfer printing on record paper.

Color copier

An image reproducing apparatus wherein a halftone of an image is reproduced by repeating a picture element pattern composed of a plurality of dots as a unit and each dot display density of which is gradually controlled. The repetition of the same picture element patterns is avoided to improve tone reproducing performance. The image display unit includes a means for determining a disposition of dots composing a specific picture element pattern, i.e., display density of each dot in response to tone density of the original image, a means for comparing the disposition of dots of the specific picture element pattern determined by said means with a dot disposition or dispositions of one or plural surrounding picture element pattern or patterns, and a means for changing the dot disposition of said specific picture element pattern in the case when it is identical with dot dispositions of a predetermined number or more of surrounding picture element patterns.

Image display unit capable of tone reproduction

A thermal head drive circuit for use with a thermal head comprising multiple heat generating elements for data recording comprising a heat accumulation calculating unit (36) for calculating the heat residual from prior recording steps and a pulse width calculating unit (38) for calculating the pulse widths of voltage to be applied to an element dependent on the calculated residual heat and the pulse width of the prior recording step.

Thermal head drive circuit

A thermal head drive circuit is provided in which the thermal energy applied during printing is corrected due to the black-white ratio, the thermal head's heat accumulation and the heat history data. The circuit includes a heat accumulation state operator, a pulse width calculator, a pulse width memory and a pulse width determining circuit. The circuit also includes a fundamental pulse width determining circuit and an auxiliary pulse width determining circuit for determining the additional pulse width to be applied with the output from the fundamental pulse width determining circuit.

Thermal recording apparatus

Electric energy to be applied to each heating element of the thermal head is controlled by taking into account the energy applied to the heating element one scan period before as well as the effect of heat accumulated in heating elements surrounding the heating element, and then the energy thus controlled is recorrected taking into consideration the temperature change in a thermal head base plate or the change in printing time between lines.

Compensation for heat accumulation in a thermal head

An image displaying device uses a thermal head to selectively create a magnetization pattern on an endless belt magnetic recording medium according to a signal applied thereto by heating the magnetic recording medium to its Curie temperature. Polarized light is then passed through or reflected from the belt and fed to an analyzer to obtain an image.

Image display device

A thermal recording head is provided with a driving system wherein higher printing speeds may be obtained. Particularly, in the case where the image to be printed by a divided block of elements is totally black, all common driving terminals corresponding to the block are selected for simultaneous recording.

Driving system for thermal recording head

In a thermal printing utilizing a heat sensitive printing paper or an ink donor film, sticking of a heat sensitive color developing layer on the printing paper or a substrate film of the ink donor film to a thermal head is prevented by supplying a predetermined amount of electric energy to heat generating elements of the thermal head during time intervals between successive printing heat generations in the heat generating elements. For this purpose, warming pulses generated from a warming pulse generating circuit are applied during the time intervals to the heat generating elements for warming the same.

Thermal printing method and apparatus

A method and device for driving a thermal head taking into consideration not only picture data already recorded and picture data on the line containing the aimed data currently being recorded, but also picture data intended to be recorded.

Thermal head drive device

A thermo-sensitive recording apparatus individually controls the energization level of each of a plurality of heater elements formed on a substrate and constituting a thermal print head. In generating each energization level, the present and previous status of an individual heater element and selected neighboring elements are taken into consideration. Other factors combined in a selectively weighted manner include the latent heat of the individual heater element and its neighboring heater elements, the resistance of the heater element, the percentage of heater elements to be activated during the printing of a line, and the temperature of the substrate.

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Kanagawa, Japan

Haruhiko Moriguchi