| 摘要 |
1,187,948. Electrostatic printing; optical projectors. NATIONAL CASH REGISTER CO. Jan.31, 1969 [Feb.26, 1968], No.5383/69. Headings G2H and G2J. Micro-image display apparatus comprises a light source 16, a light projection system 18 for projecting a light beam 14 from the source through a microimage-bearing transparency 12 on to a display screen 20, wherein there is provided an electrostatic printing system including a mirror 54 positionable to intercept the light beam and project it towards an electrostatically charged record sheet 22a to form an enlarged latent image thereon, a shutter 34 pivotable into and out of the path of the light beam to control the exposure time of the sheet, and an electrostatic developing unit 84 to receive the exposed sheet and develop the latent image thereon. A record sheet 22 is manually inserted, from a storage tray 24, into a receiving channel that forms the mouth of a guideway 26 so as to operate a switch 31. Closure of switch 31 activates guideway rollers 32a, causes shutter 34 to block the light beam and mirror 54 to pivot into an operational position. Switch 50 operates a timer which after a predetermined interval switches off all the motors of the printing system, a vacuum pump 70 and a heating unit 102. The sheet then passes a switch 58 which activates a reversible motor 46 to position a guide slot 43 into alignment with the exit guide 44, passes a corona charging unit 60 and is fed by an endless belt 64 on to a vacuum exposure mounting 62. When the sheet reaches the exposure position a switch 72 is operated to stop the belt 64 and pivot the shutter blade 40 to allow the light to pass to mirror 54 for a time determined by an adjustable timer (78, Fig.1, not shown). Closure of the shutter reactivates the drive for belt drive rollers 66 to feed the sheet through a developing station 84 and fusing station 102. The belt 64 may have a different speed when feeding after exposure to that before exposure. The sheet finally is passed over the guide bar 42 and into a receiving tray 104. In an alternative embodiment, Fig.4 (not shown), the sheets are contained within a continuous roll (110), a cutter (118) being activated when a proper length of sheet is gauged, |
