MODE SWITCHOVER DEVICE AND METHOD

摘要

PURPOSE: To provide a computer printer system which allows efficient communication between a host computer and a printer and maximizes the utilization of resources. CONSTITUTION: When power supply is made, a printer 218 initializes an internal data register and a printer memory 222 and gives an action command to added firmware. The firmware stores the state of the printer 218 and the perfect images of the register and memory 222 at a location which is accessible in an operation mode and compresses the data of images to about 8K bytes. Then the printer 218 returns the action control to the original firmware and operates in a first operation mode. A computer 202 switches the printer 218 to a second operation mode by overwriting the internal data register and printer memory 222. The printer 218 is switched to the first operation mode after the printer 218 expands the compressed images and restores the images to their initial states.