Abstract: A cleaning unit used for cleaning the surface of a recording medium in an image forming apparatus, the cleaning unit having a head being moved so as to contact with and separate from the recording medium on the basis of the assessment of preset image forming conditions such as paper size, document size, and copy magnification, and a control section for moving the cleaning head at a detected appropriate time, wherein the cleaning head is released so as to avoid the dispersion of toner that is likely to spoil the image.

Abstract: A developing apparatus which includes a plurality of developing units individually provided with sensors for detecting amount of toner accommodated therein, includes a judging device for judging whether or not sensor outputs of other developing units are below a replenishable amount when a sensor output of one developing unit falls below a replenishing requiring amount, and a replenishing display device for urging toner replenishment, based on the result of the above judgement, with respect to the developing unit having the sensor output below the replenishing requiring amount and the developing unit whose sensor output is below the replenishable amount.

Abstract: A developing apparatus which includes a plurality of developing units individually provided with sensors for detecting amounts of toner accommodated therein, includes a judging device for judging whether or not sensor outputs of other developing units are below a replenishable amount when a sensor output of one developing unit falls below a replenishing requiring amount, and a replenishing display device for urging toner replenishment, based on the result of the above judgement, with respect to the developing unit having the sensor output below the replenishing requiring amount and the developing unit whose sensor output is below the replenishable amount.

Abstract: An electrophotographic apparatus is provided with a developing device accommodating a plurality of developer tanks and a system for preventing erroneous mounting of these developer tanks. The developer tanks contain respective developers different in color from each other and are detachably mounted in respective predetermined mounting portions of the developing device. The system includes a connector formed on each of the developer tanks, a fixed connector formed on each of the mounting portions of the developing device and a controller for outputting at least one discrimination signal and judging whether or not the discrimination signal is inputted into the controller through at least one set of connectors. The connectors in each set are electrically connected with each other when each developer tank is properly mounted in its predetermined mounting portion of the developing device.

Abstract: A copying apparatus having a prescanning function for obtaining density data to adjust copy parameters includes a correction function which eliminates the data obtained from a portion of a predetermined color, from the density data detected on a prescanning process. The density data can be restricted within a predetermined range. The predetermined range can be easily set by the user.