Shinko Electric Company, Ltd.

Shinko Denki Kabushiki Kaisha

Satoshi Iwata

Fumio Takahashi

Akikazu Toida

Junji Kawano

Kiyoshige Ishiyama

Susumu Mitsushima

Takanobu Mimura

When a print line is printed on a printing paper by supplying a print current to a thermal head, heating elements within the thermal head and a transfer ribbon are easily adhered together due to melted ink on surface of the transfer ribbon. Due to such adhering between the heating elements and the transfer ribbon, a white line is easily formed on a printing paper. In order to prevent such white line from being formed, the heating elements must be prevented from being cooled down after printing each print line. More specifically, in a period between a first time when each print line is completely printed and a second time when a printing paper is to be transported forward to a next print line, the heating elements are heated by relatively small heating value which is sufficient to melt a adhering portion formed between the heating elements and the transfer ribbon but which is insufficient to perform the printing. Thus, the heating elements are prevented from being adhered to the transfer ribbon, so that each print line can be printed with accuracy and without forming the white line.

Printing method of thermal printer

The image data including a grid pattern to be printed by a thermal printer line by line is stored for three lines of dots in a plural line buffer, and the image data is scanned by a window frame of an inverted T-shape which covers the three lines. When a dot arrangement extracted by the window frame including an object dot and its surrounding dots coincides with a predetermined window frame pattern defined in an intermediate table, an address representing the dot arrangement is convertred into an intermediate code by the intermediate table. The intermediate code indicates the amount of heating energy to be supplied to a heating element corresponding to the object dot in order to preheat when the area of the object dot is a non-printing area, or to heat additionally when this area is a printing area, thereby to prevent a thin or broken portion from appearing in the printed pattern line.

Method and apparatus for energizing thermal head in accordance with dot

A thermal transfer type printer prints a desirable dot pattern on a printing paper by heating heating cells within a thermal head which is pressed against the printing paper via a transfer ribbon, the surface of which is painted by thermal melting ink. A memory stores two kinds of current-on time data, each of which represent specific current-on time characteristics designating a relation between the current-on time and a surrounding temperature of the thermal head. This surrounding temperature is detected by a thermistor mounted on the thermal head. One of two current-on time characteristics can be arbitrarily selected, and desirable current-on time is read from the selected current-on time characteristics based on the detected surrounding temperature. Some heating cells are selected in accordance with the desirable dot pattern and the selected heating cells are heated for the desirable current-on time. In addition, the current-on time can be arbitrarily set longer or shorter by increasing or decreasing the value of the current-on time data, whereby the printing density can be arbitrarily varied.

Thermal transfer type line printer capable of setting printing density

A method of thermally printing a multicolor image on a print paper is disclosed. With this method, a lengthy multicolor image can be printed on a paper over a plurality of pages of a length determined by a length of each ink zone of an ink ribbon. First, the ink ribbon is set over a platen roller with the paper being interposed therebetween, the ink ribbon having plural groups of ink zones, the ink zones of each group carrying a plurality of heat-dissolving inks of different colors, respectively. One of the ink zones is positioned at a printing position where a thermal head contacts with the platen roller through the ink ribbon and paper. The thermal head is then activated in accordance with image data stored in a memory, and the ink ribbon and paper are advanced to effect transfer of ink so that one of color component images of the image is printed on the paper. The ink ribbon and paper are then advanced by a predetermined distance to separate the paper from the ink ribbon. The paper is then backwardly moved by a distance equal in length to the total advance of the paper effected in the transferring of ink and the separation of paper. The above operation is cyclicly carried out with respect to the other ink zones to form the multicolor image on the paper without effecting the backward movement in the final cycle. If image data is still present in the memory or if a command for causing the print operation of the image to continue is received, the paper is backwardly moved by a distance substantially equal in length to the advance of paper in the final separation of the paper.

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Ise, Japan

Satoshi Iwata