Title:
PATTERN DETECTOR
Document Type and Number:
Japanese Patent JPS63229315
Kind Code:
A
Abstract:
PURPOSE:To prevent the lowering in the capacity of an auxiliary linear light blocking body, by supplying a current to the auxiliary linear light blocking body from a power source prior to the detection operation of a pattern to be detected and burning off the dust adhered to the auxiliary linear light blocking body. CONSTITUTION:Prior to a detection operation, a power source 13 is turned ON to supply a current to an auxiliary linear light blocking body 4 and said light blocking body 4 is brought to a hot-red state to burn off the dust adhered thereto. By this preparatory operation, the light blocking body 4 becomes a harmless one generating no reflection since the dust is removed or said light blocking body becomes a black opaque body. As a result, pattern omission is eliminated and a protruding part caused by reflected light due to dust is not generated in the wave form of a detection signal. An ideal black line region 6 is obtained by the cooperation of a linear light blocking body 2 and the auxiliary linear light blocking body 4 and the adverse effect of the light from the circumferential bright part 5 is not received.
Inventors:
OKA KOJI
ANDO MORITOSHI
ANDO MORITOSHI
Application Number:
JP6242387A
Publication Date:
September 26, 1988
Filing Date:
March 19, 1987
Export Citation:
Assignee:
FUJITSU LTD
International Classes:
G01B11/24; (IPC1-7): G01B11/24
Attorney, Agent or Firm:
Aoki Akira