Title:
POWER SUPPLY
Document Type and Number:
Japanese Patent JP3628784
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a power supply which can operate an exhaust fan for a certain time in a laser printer after turning off without providing an auxiliary power source.
SOLUTION: When a switch S1 breaks, an LED is turned off, and a photodetector connected with this by a photocoupler Q4 is turned off. Hereby, the +5V power supply of to the digital circuit of a printer breaks, but by a timer circuit 34, a photo-DIAC 32 keeps an on condition, and for the TRIAC 30, the on condition is maintained. During about three to four minutes in which this condition continues, and an exhaust fan 14 remains operating. After that, the output of the timer circuit goes off, and the photo-DIAC 32 is turned off, whereby the TRIAC 30 goes off, and the supply of an AC current to the front end 24 of the switching power supply stops.
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Inventors:
Bee Mark Heerst
Application Number:
JP31957995A
Publication Date:
March 16, 2005
Filing Date:
November 14, 1995
Export Citation:
Assignee:
HEWLETT-PACKARD COMPANY
International Classes:
G03G15/00; G03G21/00; G03G21/20; G05F1/10; H02J9/00; H02M7/06; H02M7/12; H03K17/292; H03K17/689; (IPC1-7): H02M7/06; G03G21/20; G05F1/10
Domestic Patent References:
| JP1200375A |
Foreign References:
| DE3943193A |
Attorney, Agent or Firm:
Masaki Goto
Yoshio Matsuda
Yoshio Matsuda