GB901533A - Image forming apparatus and method - Google Patents

Abstract

901,533. Printing processes. RANKXEROX Ltd. Oct. 2, 1958 [Oct. 2, 1957], No. 31547/58. Class 100 (2). In a method of recording characters, an insulating layer, having its surface coated with electroscopic material, is placed with its coating against an image-receiving surface and an electric field is applied in image configuration so that a quantity of electroscopic material in corresponding image configuration is transferred to the receiving surface. The field is produced between a character face and a plain electrode. The character face is spaced from 2 to 250 microns from the adjacent layer, which may be the insulating layer or the receiving surface, and the field strength is from 6 to 40 volts per micron. The field produced between the type slug 13, Fig. 1, and the electrode 14 by the battery 16 is insufficient to transfer the material 15 from the layer 12 to the surface 11, but when the switch 17 is closed, an additional pulse from the battery 18 causes transfer. Alternatively, on depressing and raising a contact arm 20 while the contact arm 9 is in the opposite position to that shown, a condenser 21 is first charged, and then discharged through the primary of a transformer 23, producing a transfer pulse in the secondary. In another form, Fig. 2, the receiving surface is a web 11 fed from a roll 42 between a series of electrodes 36 and a rotatable cylinder 32 of dry paper, plastic, or other insulating material carrying electroscopic powder coated thereon by a brush 40, and past an image-fusing hot plate 43. Independently rotatable within the cylinder 32 is a conductive drum 30 including a plurality of axially-spaced annular rings each bearing in relief the letters of the alphabet and the numerals, the drum 30 being rotated one revolution for each line-space feed of the web. Rotating with the drum is an iron disc 35 having a series of slots, or a disc carrying a series of magnetic spots, the slots or spots corresponding to the characters and which in passing a magnet 125 causes a pulse to be passed to an input storing circuit 122, which also receives a character signal from a computer through a condenser 121. When the required character is passing the electrode 36, there being an electrode and pulsing circuit for each character ring, the correspondence of the signals from the conductors 123, 121 causes a pulse to the grid of a triode 119 and a transfer pulse to the corresponding electrode 36. A second disc having one magnetic spot may be provided as a drum revolution counter. Alternatively, the insulating layer may be a web pre-coated with electroscopic material, fed between rolls and between the web 11 and the drum 30 being supported on discs at the ends of and slightly larger than the drum. Specification 734,909 is referred to.