公开(公告)号：KR1019890012798A

公开(公告)日：1989-09-19

申请号：KR1019890001534

申请日：1989-02-10

Applicant: 프라이머리 피디씨, 인코포레이티드

Inventor： 윌리엄티이.플러머

IPC: B41J25/304

Abstract: 내용 없음.

公开(公告)号：KR100133076B1

公开(公告)日：1998-04-15

申请号：KR1019890001534

申请日：1989-02-10

Applicant: 프라이머리 피디씨, 인코포레이티드

Inventor： 윌리엄티이.플러머

IPC: B41J25/304

CPC classification number: H04N1/0678 ,  G01D5/264 ,  G01D5/36 ,  H04N1/047 ,  H04N1/06 ,  H04N2201/02416 ,  H04N2201/02439 ,  H04N2201/03108 ,  H04N2201/0471 ,  H04N2201/04724 ,  H04N2201/04727 ,  H04N2201/04729 ,  H04N2201/04731 ,  H04N2201/04734 ,  H04N2201/04755 ,  H04N2201/04756 ,  H04N2201/04789 ,  H04N2201/04791 ,  H04N2201/04794

Abstract: A system for precisely positioning a printing element relative to a rotating drum, as in a drum printer, employs two position signals for alignment purposes. A pair of linear grids is disposed along a path of travel of the printing element for generating, with the aid of optical beam and sensor devices, a periodic electric signal which varies in accordance with printing element position. One of the grids is stationary and the second of the grids moves with a carriage supporting the printing element. An encoder positioned alongside the drum is operative with a set of markings having a variation in spatial frequency, or a grid overlay, to produce an alternating electric signal which varies in accordance with rotational position of the drum. Motors which rotate the drum as well as a lead screw which translates the printing element may be constructed as synchronous motors to permit phase locking to each other. Circuitry responsive to periodic signals outputted by the linear grids and the encoder introduce phase shift between motor drive signals to align position of the printing element with position of the drum independently of any backlash which may be present between the lead screw and the carriage driven by the lead screw.