Abstract: An image forming apparatus includes a pair of fixing rollers having a heater, a heater controller for outputting a turn-on/off signal to the heater, a sensor for detecting a turn-on/off state of the heater, a generator for generating a signal during an image forming operation and a prohibiting controller for cutting off a power supply to the heater when the signals from the heater controller, the sensor and the generator are simultaneously supplied.

Abstract: An image forming apparatus for electrophotographically producing a toner image on a recording sheet medium, a toner image fixing assembly which includes a heater unit having an operative condition to thermally fix the toner image on the recording sheet medium, a power supply circuit for electrically energizing the heater unit through a switch, a microprocessor unit for controlling the power supply circuit, the microprocessor unit being operative to supply to the power supply circuit a control signal effective to actuate the switch to cyclically close and open for a predetermined period of time for the purpose of inspecting the heater unit for any malfunction, a detecting element directly responsive to the condition of the heater unit and operative to produce a signal indicative of the detected condition of the heater unit, a malfunction detector network responsive to the signal from the detecting element, the malfunction detector network being operative to produce a malfunction signal indicating a malfunction

Abstract: A waste toner recovery device for use in electrostatic copying machines has a sensor and control unit which provide an advance warning when the volume of waste toner in a waste toner recovery bottle reaches a specific warning-start quantity. The control unit allows a desired value corresponding to the warning-start quantity to be selected in the copying machine.

Abstract: Copying apparatus is provided in which outline copying for only a designated area of an original image can be easily selected. An area for the outline copying can be designated and images inside and outside the designated area can be copied in different colors. The arrangement includes a plurality of keys for designating an area of an original image to be copied and a scorotron charger for causing a potential in areas other than the outline portions of an electrostatic latent image, formed on a photoreceptor drum, to be substantially equal to a potential in an area containing the image. An eraser unit is provided for erasing the charge in an area where development is not required and a developing device develops the electrostatic latent image. A transfer charger is provided for transferring the image developed by the developing device onto copying paper.

Abstract: An illuminating device for image exposure in an electrophotographic copying machine, which employs a fluorescent lamp whose voltage is variable as an illumination source and has signals to indicate when the copying machine is ready to make copies and to tell when the light amount for illumination is insufficient after preliminary lighting being performed for a fixed amount of time. A temperature sensor to detect tube wall temperature of the fluorescent lamp and a light sensor to detect the amount of light emitted from the lamp installed in the device to permit the preliminary lighting of the fluorescent lamp to be carried out at an appropriate voltage. Therefore, clear copies are readily made soon after the power of the copying machine is turned on, and, electric power waste and/or serious troubles of the machine which may occur by further use as well as exhaustion of the lamp by unnecessary high voltages can be avoided.