Abstract: An image forming apparatus includes a fusing device comprising of a fuser roller, which fuses toner on a sheet of paper, and a pressure roller getting into contact with the fuser roller to form a nip between them where the sheet of paper passes through. A fuser-side external heat roller having an internal heater comes into contact with the fuser roller. A pressure-side heat roller having an internal heater comes into contact with the pressure roller. The fuser roller and the pressure roller have approximately same outer diameter and are both composed of an elastic material. An approximate radius of the nip formed between the two rollers is set to be equal to or larger than a radius of the fuser roller or the pressure roller. In another construction, the rollers are different in outer diameter, but each composed of an elastic material and a nip between them is set to be equal to or larger than 1.25 times as large as the radius of either the fuser roller or the pressure roller with smaller outer diameter.

Abstract: The invention seeks to provide an electrophotographic apparatus, which can have a simplified and safe construction in an image forming apparatus using an a-Si photo-sensitive drum and form clear images free from the flow of image or "fog". The image forming apparatus that is sought uses image development a non-magnetic uni-component toner prepared by a polymerization process as a preamble, and is characterized in that a developing roller is rotated in contact with an a-Si photo-sensitive drum via a layer of non-magnetic uni-component toner. The volume resistivity of the developing roller is set to 3.times.10.sup.7..OMEGA. cm or below. The photo-sensitive drum has a surface layer with an element ratio composition represented as (a-Si.sub.1-x C.sub.x :H), x being 0.95.ltoreq.x<1, the dynamic push hardness of the outer surface of the surface layer being 300 kgf/mm.sup.

Abstract: An apparatus for printing directly on plain paper, utilizing an arrayed control grid having a plurality of toner slots disposed in a space between a toner carrier and a backing electrode on which a paper travels. The backing electrode formed in a flat plate facing paralleledly to the control grid assures a uniform electrostatic field in an interspace therebetween. A unit body associated with the toner carrier and the control grid makes the interspace open when the unit body is removed from the apparatus body which offers an easy access to the interspace and the members as well. A resiliently suspended backing electrode with a spacer, a restriction member etc., assures the interspace constant. Other unit bodies including the control grid associated with the backing electrode and others are also disclosed.

Abstract: An electrophotographic apparatus using an a-Si photosensitive drum. The a-Si photosensitive drum has a thickness between 2 and 25 .mu.m. The initial charging potential on the photosensitive drum is set to 450V or below. The center exposure wavelength of an exposure means is set to 700 nm or above. The photosensitive drum includes a photoconductive layer formed as a thin film a-Si layer having a temperature characteristic of 1.0 V/.degree.C. or below. For realizing low charging potential and low electric field development, the thickness d of the photoconductive layer in the photosensitive drum is set to 2 to 24 .mu.m, the relative dielectric constant .epsilon.r is set to 2 or above, and the ratio d/.epsilon.r is set to 9 or below.

Abstract: An apparatus and method for printing directly on plain paper, utilizing an arrayed control grid having a plurality of toner slots. An alternating electrostatic field in a space between a toner carrier and a backing electrode gives toner a vibrational motion to prevent a toner clog at the slot. The field is also formed to repel the clogged toner back to the toner carrier, or to fall it down on a paper on the backing electrode during no print is performed to clean the control grid. A constitution of conductive and dielectric materials for the members assures to form the field.