Hitachi, Ltd.

Shouji Saitoh

Akira Sasaki

Akiyoshi Hakoyama

Takeshi Kato

Kazuyuki Mashiko

In a laser beam printer, printing information is sent from plural hosts and printing is carried out according to the printing information. A printing paper cassette detachment inhibition mechanism unit is provided on a printing paper cassette. The paper cassette detachment inhibition mechanism unit includes fixture grooves provided on the printing paper cassette and stop levers provided on a printing paper cassette mounting port. The printing paper cassette detachment inhibition mechanism unit inhibits the detachment of the printing paper cassette when the printing paper in the printing paper cassette has been selected for use by one of the hosts. A selected printing paper cassette display unit is provided on the laser beam printer and displays the selected printing paper cassette.

Information printing system having information processing apparatuses

A laser beam printer comprises a frame memory of one page part and a compression means for compressing a dot data in the frame memory. The compression means compresses to make a compressed and encoded data. The laser beam printer comprises further a memory operable for storing dividedly a plural pages part of the compressed and encoded data and an extension means for decoding and extending the encoded data in the memory by synchronizing with a printing timing. The data compression in the frame memory and the decoding/printing of the dot data in the encoded data memory carries out in parallel. A printing in the laser beam printer can be realized at a high speed.

Text information processing apparatus having printer and printing dot

A clock signal generation apparatus is disclosed in which an original signal source generates an original clock signal, a first frequency divider starts dividing the frequency of the original clock signal in response to the rise of the original clock signal and produces a frequency-divided clock signal, a second frequency divider starts dividing the frequency of the original clock signal in response to the fall of the original clock signal and produces a frequency-divided clock signal, a sync timing signal source generates a sync timing signal, and a selection circuit renders effective selected one of the first and second frequency dividers in accordance with a level of the original clock signal at selected one of the ride and fall timings of the sync timing signal thereby to produce the frequency-divided clock signal of the effective frequency divider as a clock signal.

Clock signal generation apparatus

A thermal head for use in a dot-matrix printer is disclosed in which a plurality of heating elements for printing dots on recording paper are arranged in a line oblique with respect the moving direction of the thermal head, the dimension of the heating surface of each heating element in a direction parallel to the moving direction of the thermal head is made smaller than the dimension of the heating surface in a direction perpendicular to the above moving direction, each of wiring conductor pairs for supplying a current to the heating elements is extended from both ends of the heating surface in the lengthwise direction thereof, in a direction perpendicular to the moving direction of the thermal head, one wiring conductor of each wiring conductor pair is connected to a common wiring conductor, and the other wiring conductor of each wiring conductor pair is connected directly to a drive circuit.

Thermal head

A thermal printer comprising a print head having many thermal resistors, a movable carriage with the print head mounted thereon, and a ribbon cassette mounted on the carriage. Print data transmitted from a host system, such as a personal computer, in the form of character code is conducted through a processor into character buffers separately for each line, the print data are transformed into dot-matrix data by character generators CG(L) and CG(S), the converted dot matrix data for two lines are stored through the processor into a dot line buffer, the contents of the dot line buffer are transferred to a shift register, and a head driver for the thermal resistors is activated in response to data from the shift register.

Thermal printer

A thermal printer includes an inked ribbon, an inked ribbon take-up mechanism, a print head with two arrays of thermal resistance elements, a carriage mounting the print head, and a controller for controlling the print operation. The printer is provided with print mode switching circuit which selects low-speed print mode in which one array of thermal resistance elements is activated for each dot pitch for printing, or high-speed print mode in which the two arrays of thermal resistance elements are activated alternately for every dot pitch for printing. The printer having the print head with two thermal resistance elements is capable of high-speed printing and also high quality printing at a low print speed.

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Takahagi, Japan

Shouji Saitoh