Patent GB-1168085-A (GB)
Title: Improved Electrophotographic Apparatus
IPC: G03G15/28
Filed: 1966-10-07
Abstract: 1,168,085. Electro-photographic apparatus. CANON CAMERA CO. Inc. Oct.7, 1966 [Oct. 11, 1965; Oct.27, 1965; March 23, 1966(2); June 14, 1966; Aug.23, 1966; Aug.25, 1966; Aug.31, 1966; Sept.14, 1966], No.44947/66. Heading G2H. An electro-photographic apparatus uses an electro-photographic member 1 having an insulating layer 1 3  covering a photo-conductive layer 1 2  on a conductive or insulating base layer 1 1 . The member 1 is electrostatically charged, then simultaneously exposed and charged by A.C. or D.C. charging, uniformly illuminated, developed, the developed image is transferred, and the residual developer is cleaned from the member 1 prior to re use. The image forming process is as described in Specifications 1,163,405, 1,163,406, 1,163,408 and 1,163,410. Electrostatically charging. The member 1 is mounted on a reciprocatory plate 50, Fig.8 (not shown) beneath a charging apparatus E, Fig. 2, having primary 30 Fig. 7 and secondary 36 charging devices and a lamp 35 for uniform illumination. The apparatus E is movable from the right to the left side of plate 1, Fig. 2. The primary charging device is supplied by a terminal (X, Fig. 27 not shown) with high voltage D.C. and the secondary device with a higher A.C. voltage by a terminal (Y) or by a D.C. voltage by a terminal (Y, Fig. 28 not shown) of opposite polarity to the primary device. A.C. supplied to the primary coil of a transformer (150) generates a voltage on the secondary coil and by means of a rectifier (151) and smoothing device (152, 153) is converted into D.C. Exposure apparatus. An original 2, Fig.3 (not shown) is illuminated by a lamp 1 reciprocated on guide rails (14 1 , 14 2 ) for such that an image is formed by projection through a slit (32, Fig.7 not shown) by the optical system Fig.4 (not shown) on the reciprocating member 1. In another embodiment a microfilm reader and copying apparatus Fig.33 (not shown) has an optical system including a semi-transparent mirror 186 as shown in Fig.34, such that film F is simultaneously projected on to member 1 and on to screen 180. Developing apparatus. The member 1, Fig. 11, reciprocates above a container 77 containing developer 80 comprising toner and carrier particles agitated by stirrers 81. A permanent magnet 67 sandwiched between non-magnetic members 68 1 , 68 2  within a cover 65 forms a magnetic brush in engagement with the latent image on member 1. In a modification, a cylindrical rotatable magnet (67<SP>1</SP>, Figs.13 and 14 not shown) is provided to permit removal of magnetically adhering developer forming the brush. In another modification, a box (86, Fig. 15 not shown) has a fur brush 87 reciprocated above the member (1, Fig. 16 not shown) and supplied with toner through openings 86 1 , 86 2 ) for developing the latent image. In another modification, an endless fur brush 257, Fig. 38 is supplied with toner from a hopper through a rotary metering device 252. The endless belt 257 passes over rollers e.g. 258 to which a bias voltage is applied of the same polarity as the toner to repel toner from the brush. As brush separates from the plate a voltage of opposite polarity to the toner is applied to the brush when the brush attracts toner from the non-image area of drum 216. In another embodiment, Figs.42 to 44 (not shown) a rotating insulating cylinder (284) surrounds an electromagnet for forming toner (80) into a magnetic brush. A magnet (297) is positioned inside drum (216). Feeding copy sheets fixing apparatus. Copy sheets P, Fig. 19, are fed singly in succession by a roller 123 between roller 117 and member 1 to effect transfer of a developed image on to the sheets P. An arcuate guide 115 guides the sheets P on to the member 1, while a stripper 131 removes sheets after transfer such that they are fed to a conveyer (137, Fig. 22 not shown) beneath a heater H having infrared lamps 142. The stripper 131 is assisted by air jets (135 1 , 135 2 , Fig. 24 (not shown). Cleaning electro-photographic plates for re-use. A plate 96, Fig. 11, wipes off residual developer from the member 1 after transfer, such that the developer is returned to container 77. The cleaning may be assisted by a pump (99, Fig. 17 not shown) and by applying a bias voltage, of opposite polarity to the toner, to the plate (96, Fig. 18 not shown). In other embodiments a roller (300, Fig.47 not shown), a fur brush (311, Fig.48 not shown), and radially disposed rubber plates 308 Fig.49 (not shown) are provided for removing toner from the developed surface.