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:
Nov. 10, 1987
Filed:
Mar. 17, 1986
James D Allen, Rochester, NY (US);
David M McVay, Rochester, NY (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
A toner concentration monitor senses changes in the effective dielectric constant of a developer mixture whose dielectric constant changes with variations in the toner concentration in the mixture. The monitor is the type having a capacitive probe immersible in developer mixture such that the capacitance value of said probe varies with the effective dielectric constant of the mixture. Means are provided for creating an electrical pulse train signal of predetermined frequency and variable pulse width. The pulse width is adjusted in response to the capacitance value of the probe. The pulses are created by a multivibrator circuit which is turned on by clock pulses and which has a time constant determined by the capacitance value of the probe. Each pulse has a first portion of fixed duration and a second portion of duration variable with the capacitance value of said probe. Means may be provided for attenuating the duration of said first portion relative to said second portion so as to increase the percent of the total pulse attributable to the second portion.