Kabushiki Kaisha Toshiba

Tsutomu Kanai

Tadayoshi Ohno

Hitoshi Nagato

Shuzo Hirahara

Kiyoshi Yamada

Kazuhiko Higuchi

Yasuo Hosaka

Toshikazu Matsui

Akito Iwamoto

A method and device of toner image transfer for an electrophotographic printing apparatus capable of obtaining stable high quality images regardless of the environmental conditions. The device includes a transfer roller having an outermost resistive layer; a flexible conductive layer inside the outermost resistive layer which is electrically connected to the resistive layer; an elastically deformable elastic sponge rubber layer inside the conductive layer; a metallic shaft inside the elastic sponge rubber layer to which a transfer bias voltage is applied; and an elastically deformable elastic conductive portion electrically connecting the metallic shaft and the conductive layer. In carrying out the method, the transfer bias voltage is applied in pulsed form. Also, an area to be transferred is detected by a sensor, so that toner is supplied only to the detected area, while controlling a leveling blade located around a sleeve of a developing device for limiting the amount of toner on the sleeve, such that an amount of the toner supplied from the sleeve is changed.

Toner image transfer method and device for electrophotographic printing

In a thermal ink transfer printer, a print head and ink ribbon are mounted on a carriage which is moved at a first speed in a first direction along a recording paper in a first recording mode and also moved at the first speed in a second direction along the recording paper in the second recording mode. The ink ribbon is continuously fed in the second direction in the first and second modes and slides on the distal end of the print head so that ink is transferred from the ink ribbon onto the paper. Thus, the ink ribbon can be moved, relative to the paper, at a first speed and at a second speed which is different from the first relative speed.

Thermal inked ribbon printer mechanism

A halftone image printing device for printing an image consisting of picture elements arrayed in a zig-zag fashioning. Each picture element is composed of dots forming a quasi-diamond-shaped matrix. The dot matrix is a 2 (row) x 3 (column) matrix with two additional dots located at the top and bottom, respectively. The range of optical density, within which the densities represented by the picture elements fall, is segmented into sub-ranges. Different heating-resistors are assigned to each sub-range of density. The dots printed by the heating-resistors assigned to any sub-range of density forms a 'dot pattern' of a specific shape. The first dot pattern has one dot printed on the upper-central part of the rectangular matrix. The second dot pattern has three dots forming an L-shaped pattern, the first dot printed on the upper-central part of the matrix, the second dot printed above the first dot, and the third dot printed to the right of the first dot. The third dot pattern consists of five dots forming a cross, the first dot printed on the upper-central part of the matrix, the second dot printed above the first dot, the third dot printed to the right of the first dot, the fourth dot printed below the first dot, and the fifth dot printed to the left of the first dot. And the fourth dot pattern consists of five dots forming a cross and an additional dot printed immediately below the cross. Of the dots of each dot pattern, the dot on which energy concentrates more than any other dot assumes the same location for all dot patterns.

Halftone image printing device

In an electrothermal printer with a resistive ink ribbon, ink ribbon is fed in a predetermined direction and is contacted with a recording electrode and first and second return electrode which are located upstream and downstream of the predetermined direction with respect to the recording electrode. The first return electrode is directly connected to the ground and the second return electrode is connected to the ground through a resistor. A signal current is supplied from the recording electrode to a conductive layer of the ink ribbon through a resistive layer and the signal current supplied to the conductive layer is supplied to the return electrodes through the resistive layer. Heat is generated at a portion of the ink ribbon, which is contacted with the recording electrode and is applied to the ink layer through the conductive layer, thereby printing an ink of the ink layer to a paper.

Electrothermal printer with a resistive ink ribbon and differing

In an electrothermal printing apparatus, ink ribbon is fed in a predetermined direction and is contacted with a recording electrode and a return electrode which is located upstream of the predetermined direction with respect to the recording electrode. A signal current is supplied from the recording electrode to a conductive layer of the ink ribbon through a resistive layer and the signal current supplied to the conductive layer is supplied to the return electrode through the resistive layer. Heat is generated at a portion of the ink ribbon, which is contacted with the recording electrode and is applied to the ink layer through the conductive layer, thereby printing an ink of the ink layer to a paper.

Apparatus for transferring ink from ink ribbon to a recording medium by

A halftone image printing device represents an image using a pixel matrix, prints each pixel as a dot pattern constituted by predetermined dots in a dot matrix, and controls the dot pattern and the printing density (multilevel density) of each dot included in the dot pattern in accordance with the density (multilevel) of the pixel. An overall printing density range is divided into four density ranges, i.e., from the lowest to the highest density ranges, and each pixel is defined by a 3.times.3 dot matrix. A dot pattern in the lowest density range has a dot at the center of the matrix, a dot pattern in the next lowest range has dots at the center of the matrix and at positions above and to the right of the center, a dot pattern in the next highest density range has dots at the center of the matrix and at positions above, below, and to the right and left of the center, and a dot pattern in the highest density range has dots at the center of the matrix and at positions above, below, to the right, left, and upper right of the center. In order to print each dot at each density level in each density range, the level of energy supplied to the heating element of the thermal head corresponding to each dot is precisely controlled.

A color image printing apparatus prints one pixel by superposing a predetermined dots of three colors within a 3.times.3 dot matrix in accordance with a density of the pixel. The positions of the printed dots within the dot matrix are stored as a dot pattern for each color. One dot pattern is used for each of a plurality of densities included in one density range. The printing energy for each of the dots included in the dot pattern is controlled in accordance with the density level of the pixel. The dot pattern is different for each color and three dot patterns are stored for each color and for each density range. These three dot patterns are repeatedly used for every three pixels which are continuous in the horizontal direction. These three dot patterns have two or three texture directions. The texture direction other than the vertical direction is different for each color.

Color image printing apparatus

A thermal transfer printing apparatus has a thermal head comprised of a plurality of heating members aligned in line, each of the heating members transferring an ink to printing paper upon heating so as to form one dot, the thermal head moving relative to the printing paper and defining a pixel using m.times.n printing dots (m, n: positive integers). This apparatus further has multilevel dot pattern generating means for storing several binary dot patterns having predetermined dots of the m.times.n dot matrix, and for selecting, upon reception of an image signal indicating the density of each pixel, a binary dot pattern in accordance with the density of each pixel, determining multilevel data for each dot constituting the selected pattern in accordance with the density of each pixel, and generating the multilevel dot pattern in which the data for each dot is determined, and driving means, connected between the multilevel dot pattern generating means and the thermal head, for heating, in correspondence with a multilevel dot pattern, the heating member corresponding to the dot therein so as to transfer an ink onto the printing paper to form a dot pattern formed by dots having a size corresponding to the density of each pixel.

Growing community of inventors

Yokohama, Japan

Tsutomu Kanai