Abstract: A charging device for charging a desired object such as a photoconductive element of an electrophotographic copier, laser printer or similar electrophotographic recording apparatus, and a discharging member of the same. The discharging member is implemented by a resistor and located such that the surface of one end thereof defines a discharging end that faces the object with the intermediary of a gap. The other end of the discharging member is connected to a power source via a conductive connector. The discharging end is provided with any one of various alternative configurations. The resistor is covered with a protective covering. A conductive member is adhered or otherwise securely mounted between the resistor and the conductive connector. The resistor is supported by an insulative substrate. On the substrate, the resistor is divided into a plurality of discrete resistors so as to form a plurality of discharge gaps therebetween which are selectively usable.

Abstract: An information display medium includes as a main component a thermosensitive material layer which can reversibly repeat turbid and transparent conditions by being heated to different temperatures and can keep one of such conditions stably below a particular temperature, one of the turbid and transparent conditions being selectable by a print head. The information display medium further includes a substrate layer combined with the thermosensitive material layer, and another layer, at least one of the thermosensitive material layer, the substrate layer, the other layer, and a background panel for use with the information display medium having a regular pattern such as a stripe or a matrix in a plane thereof, and being colored in at least two colors in the pattern for color display.

Abstract: A ventilated corona charging device for charging a charge receptor includes at least one corona wire to which a high voltage is applied, an electrically conductive shield which partly encloses the corona wire and a blower for directing a stream of air at least into a first region defined between the corona wire and the charge receptor, preferably also into a second region defined between the corona wire and the shield, in order to cause corona discharge which is uniform as well as stable.

Abstract: A copier capable of binding copy papers at their center or their edge as desired. A bookbinding device is operatively connected to a paper outlet of the copier. To bind the papers at their center, a folding mechanism of the bookbinding device is activated first in order to form a crease along the center of each copy paper. Then, a binding mechanism of the bookbinding device is activated to sequentially stack the papers in an upwardly convex form and such that the creases face upward in alignment and, then, stitch the papers together along the aligned creases by means of a staple or the like. The bound papers are discharged to a stacking mechanism of the bookbinding device in a developed position so as to be stacked there while being folded double in the creases. When it is desired to duplicate documents on papers which are equal to or double the size of the documents and bind the copies at the center, a positional relationship between the documents and the papers is set up by a unique method.

Abstract: An electrostatic image forming method for various kinds of image forming apparatuses. At an exposing step, a light image having a light quantity region greater than a predetermined quantity of light is projected to form on a dielectric layer of a dielectric recording medium a positive electrostatic image which has such a tendency that the surface potential or the amount of surface charge is comparatively small in a region in which the quantity of light is comparatively large. A full-surface exposing step using a predetermined quantity of exposing light is added to before or after the exposure to the light image, so that the total quantity of exposing light exceeds a predetermined quantity of light. The quantity of light of the light image is controllable to a larger one which provides a positive electrostatic image on the dielectric layer, or to a smaller one which provides a negative latent image.

Abstract: A copier capable of binding copy papers at their center or their edge as desired. A bookbinding device is operatively connected to a paper outlet of the copier. To bind the papers at their center, a folding mechanism of the bookbinding device is activated first in order to form a crease along the center of each copy paper. Then, a binding mechanism of the bookbinding device is activated to sequentially stack the papers in an upwardly convex form and such that the creases face upward in alignment and, then, stich the papers together along the aligned creases by means of a stapler or the like. The bound papers are discharged to a stacking mechanism of the bookbinding device in a developed position so as to be stacked there while being folded double in the creases.

Abstract: A residual toner collecting device efficiently collects residual toner remaining untransferred on a photoconductive element of an electrophotographic copier by cleaning the photoconductive element. A scavenger roller and a flat counterelectrode, which constitute the collecting device, are supplied with dc bias voltages which are different in polarity. The polarities of the dc bias voltages are switched each to the opposite polarity only for a predetermined part of the period between a start of movement of the photoconductive element and a stop of the movement. Further, an ac bias voltage is applied to at least one of the scavenger roller and the counterelectrode superposed on the dc bias voltage for the predetermined period. The predetermined period is a period during which cleaning the photoconductive element is not required.

Abstract: An electrophotographic copying apparatus including a photosensitive member having an image forming surface large enough to form a plurality of sizes of images thereon, and control signal generating means located on the image forming surface of the photosensitive member for generating signals for controlling a plurality of image forming starting positions corresponding to a plurality of sizes of images or timing of other operations of the image forming process. The invention has particular utility in application to a copying apparatus having a photosensitive member large enough to form a plurality of image segments of at least one of the plurality of sizes of images on the image forming surface in the photosensitive member. The photosensitive member may be in the form of a photosensitive drum or a photosensitive endless belt with or without a joint.