The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 29, 1990
Filed:
Apr. 20, 1989
Applicant:
Inventor:
Satoru Takemoto, Kanagawa, JP;
Assignee:
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05B / ;
U.S. Cl.
CPC ...
219501 ; 219209 ; 219497 ; 361101 ; 361111 ; 307117 ;
Abstract
A heating resistor drive circuit includes a first switching transistor, connected in series to the resistor, for connecting and cutting off a current flow supplied from a power source to the heating resistor, and a second switching transistor connected in series to the base of the first transistor. The second transistor is turned on in response to an actuation signal. The drive circuit further includes a suppressing circuit for raising gradually a base current for the first transistor up to a predetermined level while the second transistor is conductive, so as to suppress a current spike flowing through the heating resistor.