Abstract: A copying machine which develops an electrostatic latent image corresponding to an original image into a toner image, transfers the toner image on the copying paper and fuses the toner image later on the copying paper by means of a heating and fusing device, detects types of copying papers to be transferred by the toner image and when the copying paper is large in size, a fixed standstill time is arranged between the scanning and exposing operation of an original and a restoring operation to a home position is made and a fusing operation is prevented without fail when a temperature of the heating and fusing device drops below a fusing temperature.

Abstract: A method for controlling a copying machine having a copying cycle and fusing device. The fusing device is formed of a rotatable heating roller and a press roller in mutually forcible contact with the heating roller, which fuses a toner image on a copying paper at a fusing temperature upon passage through the rollers. The heating roller is heated to a first temperature above the fusing temperature. The copying cycle is delayed during a first interval of time after the heating roller reaches the first temperature. The copying cycle is set to a wait-reset state after the first time interval. The heating roller is cooled to a second temperature below the fusing temperature and the copying cycle is set to a wait state. The heating roller is heated from the second temperature to the fusing temperature during a second interval of time. The copying cycle is restored to the wait-reset state during the second time interval before the heating roller reaches the fusing temperature.

Abstract: A copying machine with a variable magnification device comprising two paper cassettes mounted in a drawable manner in vertically spaced relation and a select key for the paper cassettes, wherein the desired cassette can be selected as a source of the copying paper by operating the select key. The upper paper cassette is provided with the copying paper for variable magnification copying, and the upper cassette is automatically selected as the paper source when a detector indicates that the variable magnification copying mode has been selected.

Abstract: An automatic developing bias control device for an electrophotographic copying machine in which a document image is led onto a photoreceptor through a lens to form an electrostatic latent image on the photoreceptor and the electrostatic latent image is visualized into a toner image by a developing device, the automatic developing bias control device operating on the principle of detecting the density of the document image by a detecting element disposed inside or outside the optical path, delaying the output detection signal for a predetermined time, and imposing a developing bias potential corresponding to the delayed output detection signal on the developing device to thereby provide copy image quality faithful to the original.

Abstract: An apparatus for regulating the movement of a movable member includes a drive device for moving the movable member in a first direction from a rest position to an operative position and for moving the movable member in a second direction, opposite to the first direction, from the operative position toward the rest position. A first detector detects the presence of the movable member at the rest position. A second detector detects the presence of the movable member at a location adjacent the rest position but upstream thereof with respect to the second direction.