Photocopying – Contact printing – Light boxes
Patent
1990-04-30
1991-08-13
Grimley, A. T.
Photocopying
Contact printing
Light boxes
355208, 355246, G03G 2100
Patent
active
050400215
ABSTRACT:
A transmission densitometer determines the optical density of an electrically charged layer of toner material on a photoconductive layer by exposing the photoconductive layer to radiation through the toner layer such that the amount of exposure is characteristic of the density of the toner layer. The change in voltage on the surface of the toner layer caused by the exposure is detected, such that the change in detected voltage is characteristic of the density of the toner layer.
The measurement of the change in the detected voltage is carried out by measuring the characteristic voltage on a toner layer developed upon a photoconductive layer using a first electrostatic voltmeter, discharging the characteristic voltage on the area of the photoconductor which was measured by the first electrostatic voltmeter using the exposing device, and measuring the remaining voltage in that area by using a second electrostatic voltmeter. The difference between the first measured characteristic voltage and the second measured characteristic voltage on the tone layer is indicative of the amount of toner present on the photoconductive layer.
REFERENCES:
patent: 3674353 (1972-07-01), Trachtenberg
patent: 4026643 (1977-05-01), Bergman
patent: 4348099 (1982-09-01), Fantozzi
patent: 4614908 (1986-09-01), Daniele et al.
patent: 4708459 (1987-11-01), Cowan et al.
Barlow Jr. J. E.
Eastman Kdak Company
Grimley A. T.
Sales Milton S.
LandOfFree
Transmission densitometer by using differential comparison of el does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transmission densitometer by using differential comparison of el, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transmission densitometer by using differential comparison of el will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1530890