公开(公告)号：US3564130A

公开(公告)日：1971-02-16

申请号：US3564130D

申请日：1966-03-21

Applicant: RCA CORP

Inventor： CROOKS HORATIO N ,  HALLOWS RAYMOND L JR

IPC: B41B19/01 ,  G09G1/06 ,  H04N1/405 ,  H04N5/84

CPC classification number: G09G1/06 ,  B41B19/01 ,  H04N1/4058

Abstract: A photocopy system provides a halftone image of a picture composed of continuous tones by producing a plurality of hollow halftone dots corresponding to the continuous tones. Each of the halftone dots comprises an annulus that has a size that corresponds to the density of a tone on the original picture.