Patent ID: 7113715
Filing Date: 2006-09-26
Classification: G03G

Abstract:
1. A method of preventing contamination of a transfer roller in an image forming system, the method comprising: setting a print region for a scanning operation according to a comparison result between a previous paper size in a paper cassette and a paper size in a driver; determining a current paper size in the paper cassette based on a time when front and rear ends of the paper are detected by a paper feeding sensor; comparing the current paper size in the paper cassette with the paper size in the driver; and if the paper size in the driver is larger than the paper size in the paper cassette and the print region for the previous paper size in the paper cassette has not been set, determining a separation time of a transfer roller from a transfer belt in consideration of a delay time when the transfer roller is mechanically separated from the transfer belt after a separation command is applied to the transfer roller.