Abstract: A charging device and method of operating the device for charging a photoreceptor of an image forming apparatus so that a latent image is formed thereupon to be developed by toner, the device including a charging roller that is configured to constantly contact the photoreceptor with a pressure so as to be rotated by rotations of the photoreceptor and that is configured to charge the photoreceptor, and a charging roller cleaning member that is configured to constantly contact a surface of the charging roller with a pressure so as to remove the toner transferred onto the charging roller from the photoreceptor. A length portion of the charging roller cleaning member along an axial direction of the charging roller is set to be equal to or greater than a width portion of an effective development area in an axial direction of the photoreceptor and smaller than a charging contact width portion of the charging roller with the photoreceptor in the axial direction of the charging roller.

Abstract: An electrophotographic apparatus employing a self-heat-emitting heating roller capable of causing current to flow through a heat emitting resistor at a time of turning on a power supply until a maximum electric power to be consumed in the electrophotographic apparatus, to thereby shorten a rising-up time of the heating-roller fixing apparatus. The drive starting temperature is previously set and the heat emitting resistor is selected so as to satisfy the following inequalities:V.sup.2 /R.sub.3 .ltoreq./V.sup.2 /R.sub.2 <W.sub.max -W.sub.m .ltoreq.W.sub.1 <V.sup.2 /R.sub.0 .ltoreq.W.sub.max -W.sub.s.An image forming apparatus included in the above-mentioned electrophotographic apparatus prevents an excessive current flowing through the fixing apparatus in a case of turning on the power supply on a condition that the temperature in the apparatus does not rise up sufficiently, and thereby the apparatus is not damaged. Such an apparatus can be provided at a low cost.

Abstract: A control operation for a fixing device which may find application in an image forming apparatus such as a printer, facsimile, or copier machine, etc. The fixing device controls a temperature of a fixing element therein, for example a fixing roller, based on a calculated compensated temperature T' of the fixing roller, which is calculated based on detected temperature of the fixing element T0 and a reference environmental temperature T1 within the image forming apparatus according to the following equations: ##EQU1## in which each of A1-A4, a1-a4, b1-b4 and c1-c4 are constants. Experimental results have indicated that such a compensation temperature value T' closely approximates an actual temperature of the fixing element. Thus, with such an operation, a temperature of a fixing element can be controlled to an appropriate value.