| 摘要 |
PURPOSE:To reduce the labor and cost for separately expanding a system memory area and an image memory area in the expansion of the memory areas by a method wherein the memory means having the system memory area and the image memory area for storing developed image data is provided, and means for taking access to the respective memory areas are prohibited from simultaneously having access to the memory means. CONSTITUTION:Since external printing data is stored in a user data area which is a part of a DRAM block part 42, this data is developed to bit map data by an MPU 30. The bit map data is again stored in a video band buffer(VBB) area which is a part of the DRAM block part 42. This data is read by using a VDG 35, converted to serial data, and transmitted by a laser scan unit(LSU) in synchronism with a horizontal synchronizing signal (HSYNC). At this time, a DRAM mediation means 38 inputs an access request signal VBBRQ from the microprocessor unit(MPU) to the VBB area, an access request signal MPURQ from the MPU to an area other than the VBB area, and the like and mediates them inside so as to prohibit a simultaneous access to the memory means. |
