Printer including a formatter and a printing unit without a memory

Abstract

A printer requires no print buffer in a printer engine, and can efficiently use an image memory for bit-mapping print data into a print image. An enable signal for designating transfer of data for one page from a formatter to the engine is output in response to a request signal from the engine for requesting transmission of print data for one line. When a clock signal for requesting transfer of print data is output from the engine to the formatter in response to this enable signal, print image data is transferred from the formatter to the engine in synchronism with the clock signal and further transferred to a printhead to print an image. As to the nozzles, on the right and left ends of the printhead, which are not used for a print operation, a right margin area and a nozzle area used for a print operation are set in a data transfer circuit. With this operation, '0' is first set to a print data signal in the data transfer circuit, and reference clocks used for transferring data to the printhead are counted for the number corresponding to right margin area of the printhead. When the count operation is completed, a signal becomes active, and subsequently, print image data is transferred. When the number of reference clocks coincides with the number of nozzles corresponding to the print area, this is set to print data again. This operation is repeatedly performed for each line.