Title:
IMAGE-FORMING APPARATUS
Document Type and Number:
Japanese Patent JP3302352
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To sample detected values at a time point when a laser is turned on and detecting a laser power is stabilized by providing a time difference between a timing when a circuit for turning on/off a current to a laser element is turned on and a timing when a sample hold circuit is rendered a sample state.
SOLUTION: A slightly lower reference voltage 200 than a reference voltage 132 at a base of a transistor 108 for turning on/off a laser is connected to a base of a transistor 129. A pin 22P for turning on/off the laser is connected to a base of a transistor 128. In other words, when the pin 22P for turning on/off the laser turns on the laser, a sequence wherein the transistor 108 is first turned on, and then the transistor 129 is turned on is generated. That is, a sample hold circuit operates after the laser is turned on. A current of the sample hold circuit is determined by a current of a transistor 133, so that a stability in controlling a laser power is improved.
Inventors:
Takashi Soya
Takashi Nakahara
Akihiro Shibata
Takashi Nakahara
Akihiro Shibata
Application Number:
JP2000233114A
Publication Date:
July 15, 2002
Filing Date:
April 04, 1991
Export Citation:
Assignee:
Canon Inc
International Classes:
B41J2/44; G02B26/10; H01S5/0683; (IPC1-7): B41J2/44; G02B26/10; H01S5/0683
Domestic Patent References:
| JP63287163A | ||||
| JP1234867A |
Attorney, Agent or Firm:
Keizo Nishiyama (1 person outside)