Page printer and page print system

摘要

A host sends each page of image data to a page printer in band units and the page printer writes the received each band data into a reception buffer in DRAM by DMA and transfers the band data from the reception buffer to an image formation section made up of members. The host gets an available buffer capacity from the printer just before transmitting each band data, and transmits the band data only when the printer can receive the band data. In the printer, a CPU permits transfer DMA to be started after reception data as much as the data amount calculated based on the data reception speed and the transfer rate is stored in the buffer to prevent an underrun error from occurring. If an underrun error occurs, the CPU sets an error flag, and sends the error flag to the host just before the host starts transmitting each band data. When receiving the error flag, the host drops image resolution and resends the page data with the resolution dropped.