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:
Feb. 09, 1993
Filed:
Oct. 01, 1991
Richard L Hartman, Spokane, WA (US);
Output Technology Corp., Spokane, WA (US);
Abstract
An electrophotographic printer 10 having a control system 51 for controlling a stepper motor 50. The control system 51 includes a motor speed drive circuit 52, a microprocessor 54, and a clock 58. The motor speed drive circuit 52 has a programmable driver 56 and a logic circuit 60. The microprocessor 54 outputs a speed change value each time a change in the stepper motor is desired. The programmable driver 56 stores the speed change value and incrementally counts down from the speed change value to zero in synchronization with a clock pulse from the clock 58. Upon reaching zero, the programmable divider 56 outputs a speed command signal to the logic circuit 60, which in turn outputs drive signal to control the operation of the stepper motor 50. The microprocessor 54 only outputs a new speed change value when a change in stepper motor operation is desired. If no change is desired, the programmable divider 56 uses the last input speed value to control the stepper motor. As a result, the microprocessor 54 does not constantly interact with the stepper motor 50, and is therefore free to perform other processing tasks.