Patent GB-1408581-A (GB)
Title: Microfilm viewer-copier
IPC: G03G15/10
Filed: 1972-07-27
Abstract: 1408581 Viewer-copier SEACO COMPUTERDISPLAY Inc 27 July 1972 [28 July 1971] 35220/72 Headings G2A and G2H In a microfilm viewer-copier, the microfilm image is projected by a lens system 100 on to a semi-transparent mirror 110, which partially reflects the image on to a viewing screen 23, and partially transmits the image to a photo-copying station D through a polarizing sheet 111, the polarizing effect of mirror 110 and sheet 111 in combination being such as to block ambient light entering the viewing screen from reaching station D. The microfilm is in the form of a fiche, which is mounted in a holder 112 which is positioned on a table 28. Light from a lamp 57 is reflected from a mirror 62, through an opening 70 in the table and through the selected frame of the micro-fiche. After further reflections from mirrors 106 and 108 the projected image falls on the semi-transparent mirror 110. The light transmitted by this mirror is polarized to a degree dependent on the angle of incidence. The relative angular dispositions of mirrors 108, 110 and screen 23 are such that ambient light entering through screen 23 and falling on mirror 110 is polarized to a maximum degree, while light reflected from mirror 108 is polarized to a minimum degree. Thus the ambient light from screen 23 is blocked by the properly oriented polarizing sheet 111. The copier portion consists of an electrostatic printer having a number of stations D, E, F, G. A stack of copy sheets 202 is stored in a tray 200, of such a shape that the sheets take up a parallelogram formation, with their conductive photosensitive sides downwards. The inside surfaces of the tray 200 are coated with an insulating material, except the inclined upper wall 210, which is uncoated. This wall, which deflects the sheets towards the feedrollers 282, 283 which convey them to the charging station F, thus serves to discharge any electrostatic charge on the sheets. The top sheet is fed from the stack 200 by a pair of friction rollers 220 mounted on a shaft 222. The shaft is carried by a pair of arms (224, 226), Fig. 8 (not shown) which can swing on axles (228, 230). The rollers are driven continuously, but a solenoid (278), Fig. 9 (not shown) can be selectively energized to swing the rollers into or out of engagement with the top sheet. After being charged at station F, the sheets are conveyed to the exposing station D. This comprises a housing 304 in which a partial vacuum is maintained by an exhaust fan 330. A series of endless belts 318, carried by rollers 314, 316, pass round housing 304, and the sheets adhere to these belts because of the partial vacuum. The under section 324 of the belts form the exposure plane. The sheets then pass to a developer station G, seen in more detail in Figs (not shown) 11 and 12. The developer fluid is pumped from a reservoir to a supply manifold (344), from which it is ejected through a nozzle having a number of guide vanes (341) for controlling the flow. The nozzle extends the full width of the roller (340) over which the sheet passes, and the liquid is applied in an upward direction to the under side of the copy sheet. Just before leaving the apparatus through an exit slot 394 the sheet passes between a pair of squeegee rollers 372, 374 for removing excess developer fluid. These rollers have a slightly larger section at the centre than at the ends Fig. 13 (not shown) to compensate for any bowing produced by endloading the roller shafts to bias them towards each other.