A highly stable color laser printer has been experimentally developed, which uses a newly devised toner transfer roller, made of elastic sponge rubber sheathed with a plastic resistive layer. The developed color printer attains the following features: i. High quality full color images can be printed under broad operating conditions, e.g. from 20°C,40%RH to 30°C,85%RH. ii. Frequent color adjustment is not necessary because printed image color differences under different operating conditions are within 3. iii. The maintenance interval can be extended; the toner transfer efficiency from the photoconductor drum to the paper is above 85%. The amount of waste toner is reduced to about 1/3 of that for a conventional printer on an average.