This invention relates to a registration apparatus for a copier or printer. Registration is provided when a sheet which is being fed along a desired path is intercepted by a stop member to properly position it along the path in a timed relationship with an image means for applying the image to it.
In the past, this type of mechanism consisted of intermittently rotating rollers whose speed equaled the process speed of the photosensitive member surface, or a cam type mechanism, which fed the copy substrate or transfer material on a signal from the copying process to synchronize it with the movement of the print-forming section of the photosensitive member. For this type of mechanism it is difficult to minimize the error in matching the positions of the leading edge of the copy sheet to the print forming section of the photoreceptor below the allowable tolerance of about 2 mm. This is because it is impossible to perfectly synchronize the movement of the print forming section of the photosensitive member with the intermittent drive of the rollers due to the time difference between receipt of the signal and the rollers intermittent driving of the transfer material, the faster the rollers rotate the greater the error in adjusting the position of the leading edge of the transfer material to the print forming section becomes as a result. Also, copy substrates are sometimes captured by registration rolls in a skewed state with the substrates being transported to an image transfer station with the copy substrate remaining in the skewed state.