GB1084285A - - Google Patents

Abstract

1,084,285. Selective printing. H. GERMER. Oct. 1, 1964, No. 39958/64. Heading B6F. [Also in Division G2] Electro-graphic printing. - An electromagnetic radiation source is directed in the form of a beam 4 towards a recording surface 3 and is modified at 2 in accordance with a character or symbol to be printed and the selected beams 4a affect particles on a transfer ribbon 5 which after irradiation are caused to form a permanent visible image of the character on the record 3. Screen printers; tracer printers. -The electromagnetic beam may be a laser, profiled by a mask or stencil or it may be focused by optical means and influenced by deflecting devices whereby a facsimile or raster image is obtained. The stencils 2 may be moved into position by electromagnets. Hammer-impression arrangements. -The irradiated parts of the ribbon 5 are transferred to the record 3 by an electromagnet hammer action which squeezes the two together between a platen 10 and the hammer 7. The upper end of hammer comprises an iron sleeve which is drawn into a solenoid 6 when energized by the incoming signals. A resilient diaphragm 9 restores the hammer. Platen and roller impression arrangements. -In a modification, Fig. 3 (not shown), the platen is electromagnetically moved to shift the record up to the ribbon and in another embodiment the record is moved into contact by a roller. Multiple-web arrangements.-Several webs and transfer ribbons may be used when radiation beams outside the visible range are used, and which can effect printing simultaneously on all webs. Transfer-ribbon; ribbon mechanism. -The ribbon 5 comprises a thin radiation-permeable substance except for a thin flexible thermoplastic synthetic colour material layer 5a. To effect transfer the layer 5a is heated by the absorbtion of the radiation energy in shapes representing the character to be printed. This softens or liquifies the layer which is transferred by pressure. An additive may be added to prevent sticking. Alternatively an additional thin layer between the carrier 5 and the transfer layer 5a promotes easy removal of local heated parts. At normal temperatures the ink does not soil the fingers. The transfer material may comprise an endless band and the used parts replenished by heatable calender rolls 52, Fig. 4 (not shown), and a heatable reservoir 54. An infrared heater 55 may precede the rolls 52 to ensure uniform intensity and quality of the replenishment. In a modification, Fig. 6 (not shown), prior to entering the printing position the ribbon is electrically charged at 42 and then sprayed at 43 with a thermoplastic powder. The ribbon may be kept taut so that immediately after printing it comes away from the recording surface. In another case the ribbon is lifted from the carrier by the suction of a sleeve 12 on the hammer 7. To assist transfer of the colour material to the record 3 it may be heated by passing over a platen guide 14, Fig. 3 (not shown), heated by convection or radiation 16. A thermostat 17 controls the heating to suit ambient temperature. Ink arrangements not using ribbon, electrostatic printing. -In Fig. 7 (not shown) the ink is in the form of coloured dust particles flowing through a chamber 51 at sub-atmospheric pressure. The powder is provided with a positive charge and is normally repelled by the positive potential of electrode 52 serving as a platen guide. When radiation occurs the powder particles are irradiated by beams 4a, are discharged due to ionization taking place, and are urged towards and precipitated on recording surface 3 by action of the electrode 52.