Abstract: A multi-color image forming apparatus including an original platform, a photoreceptor, a scanning device, an image forming device for forming an electrostatic latent image on the photoreceptor, first and second developing device for developing the latent image in different colors, respectively, a movable designating device, an input device for giving a command for starting copying, a starting device for starting operation of the scanning device, the image forming device and the first developing device in response to the command from the input device, an output device for outputting a changeover signal for effecting changeover between the first and second developing devices and a control device for, in response to the changeover signal from the output device, stopping operation of the first developing device and starting operation of the second developing device.

Abstract: A multi-color image forming apparatus including an electrostatic latent image support member, a plurality of developing devices, an image forming device for forming an electrostatic latent image won the support member, a selector for selecting one of the developing devices, a pattern forming device for forming a latent image pattern on the support member separately from the electrostatic latent image in response to selection from an upstream developing device to a downstream developing device in a rotational direction of the support member by the selector and a control device which performs control such that the latent image pattern is located forwardly of the electrostatic latent image in the rotational direction of the support member, whereby after the latent image pattern has been passed through the upstream and downstream developing devices, the electrostatic latent image is developed by the downstream developing device.

Abstract: A multiple color image forming apparatus using a plurality of developing devices selectively during one image forming process to reproduce a plurality of designated areas respectively in designated color, whereby color mixing and non-developing of the reproduced image can be freely performed by setting the start and end points of the designated area responsive to a plurality of the developing devices and controlling them in response to such setting.

Abstract: The disclosure is directed to an improved electrophotographic copying apparatus which includes a detector for detecting amount of toner adhering to a reference latent image, a replenishing device for replenishing toner to a developer in a developing device when the toner amount detected by the detector falls below reference toner amount and a correcting device for changing the reference toner amount, and/or voltage of a developing bias power source at a time when the reference latent image is developed, according to an operation for altering original document projecting magnifications, so that toner concentration of the developer may be maintained in the best condition at a reduced size magnification as well as an equal size magnification.

Abstract: A toner dispensing device has a toner storage chamber provided in its lower portion with an opening for passing toner therethrough, a roller disposed within the storage chamber close to the opening and rotatable to deliver the toner from the storage chamber outward through the opening, an intermediate toner supply chamber in communication with the storage chamber through the opening and for receiving toner to keep it substantially full, and a feeder provided within the intermediate supply chamber for feeding the toner out of the intermediate supply chamber at a constant rate.