Patent GB-1030724-A (GB)
Title: Printing device
IPC: G03G15/32
Filed: 1963-03-22
Abstract: 1,030,724. Selective printing; printing apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. March 22, 1963 [March 26, 1962], No. 11437/63. Headings B6C and B6F. Screen printers; type-wheel machines; paper and matrix carriages and supports; paper, sheet feeding, guiding and heating arrangements; roller inking arrangements; electrostatic inking arrangements; roller impression arrangements.-An electrostatic printer comprises a continuously rotating thin, cylindrical drum 1, Fig. 1, on whose inner surface is disposed a micromesh screen 2, the drum being provided with openings 3, having the configuration of characters disposed in circumferential columns around the drum. Electrostatically attractable toner ink is applied to a mohair loading roller 5, which inks a velvet toner roller 4 in contact with the drum 1 and rotating at a faster speed than the drum to produce a scrubbing action. The ink is attracted and retained by the micromesh screen 2 exposed by the openings 3 by the application of a potential to a central electrode 6, within the drum 1, and the inked characters are applied selectively to a printing medium fed by a feed sprocket 7 and guided over paper guide 8, within which are selectively energizable electrodes 9, one for each character print position. Each of the electrodes 9 are connected by one of a set of leads 10 to an electrode decoder and amplifier 11. The paper guide 8 includes also a heater section 12 for setting of a toner including a resin contained in the toner ink. In another embodiment in Fig. 5, the control electrode 6 is dispensed with and the plurality of electrodes 9 replaced by a continuous electrode 39 and each character position is determined by a step-wise driven endless steel tape 40 acting as a shield and having an aperture 41 corresponding to the size of the largest character. Toner ink is contained directly in the character drum for withdrawal through the micro-mesh screen and the apertures in the drum when the electrode 39 is energized. In still another embodiment in Fig. 6, a dielectric printing web 47 is fed from a feed roll 44 over a paper guide 46 disposed between the continuously rotating character drum 401, having a continuous electrode 411 and a plurality of selectively energizable electrodes 431, whereby electrostatic latent character images are formed, which are developed at a toning station comprising toner rollers 48, 49 and subsequently fixed at a heating station comprising heat platens 50, 51. In a further embodiment (Fig. 7, not shown) the dielectric web is replaced by an endless dielectric belt, provided with a second erasure unit and the heat fixing station is replaced by paper printing medium pressed into contact with the belt for contact impression by a pair of pressure rollers. In a still further embodiment (in Fig. 8, not shown) latent electrostatic images are formed by two electrodes disposed on opposite sides of the character drum rim on a dielectric tape passing therebetween, the tonic ink being applied by a tonic roller character by character and when a line is completed a pressure roller travelling along the tape causes a line impression on the paper medium. Key actions; permutation arrangements.- Keys 25, Fig. 1, provide a parallel binary output to an appropriate number of output lines in the keyboard 22 to connect armatures 20. . . 20n of solenoids 21 ... 21n connected to arms 19 ... 19n of permutation discs 18 ... 18n rotatably mounted on shaft 13 of character drum 1, so as to bring in alignment one set of apertures on the discs to provide a passage for light being transmitted from a ring source 23, which is sensed by a photo-electric cell 15 rotating in synchronism with the drum. The emitted output impulse from the cell, which corresponds to one row characters is passed through a slipring 16, via conductors 17 to the amplifier 11, which is transmitted to a particular electrostatic electrode 9. The electrode decoder and amplifier 11 has a progression step switch (not shown) so that as the code is entered from the keyboard 22 to the permutation discs 18 the switch is stepped forward one letter space allowing the next electrode 9 in the line to be energized. Type discs and printing surfaces; typewheels.-The character drum 1, Figs. 4 and 2, comprises a cylindrical 0À004 inch thick shell having apertures 3 formed on its periphery in the shape of characters to be printed, which are disposed in identical sets in circumferential columns around the drum. On the inner surface of the drum there is provided a micromesh screen 2, to which adheres the electrostatically attractable toner ink opposite the charactershaped openings 3. The ink is made to adhere to the micro-mesh screen 2 rather than to the character drum 1, by making the screen of a material which is either higher or lower than the ink in the triboelectric series and the character drum itself of a material which is approximately equal to the ink in the triboelectric series. The character drum may have the ink brushed on by toner rollers, or it may have the ink introduced on the inside or it may be used for inkless printing in the formation of latent electrostatic images.