| 摘要 |
An electrostatographic single-pass multiple station multi-colour printer for forming an image onto a web is described. The printer comprises a plurality of toner image-printing electrostatographic stations (A, B, C, D). Each station has a drum onto the surface (26) of which a toner image can be formed. An exposure station (30) forms an electrostatic toner image line-wise on each drum surface. A corona device (34) transfers the toner image onto the web (12), which is conveyed in succession past said stations (A, B, C, D) in synchronism with the rotation of the drum surface (26). Register control means are provided for controlling the operation of each of said stations in timed relationship thereby to obtain correct registering of the distinct toner images on the web (12). The register control means comprises an encoder (60) driven by the displacement of the web to produce pulses indicative of web displacement, and delay means (71) arranged to initiate the operation of subsequent stations after a predetermined web displacement, as measured by the encoder means, has occurred. The invention enables accurate registration of the transferred images, irrespective of the speed of the paper web through the printer. <IMAGE> |
