Varying an electric field, during development of a latent electrostatic image with developer solution, in proportion to a sensed concentration of toner that is within the developer solution
US5243391A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1992 |
| Grant date | Sep 7, 1993 |
| Priority date | — |
| Expiry date | May 1, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/065
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The separation between two plates or electrodes--between which plates a developer solution is applied to develop a latent electrostatic charge image on a photoconductive medium within an electrophotographic imager--is varied in proportion to a detected concentration of toner within the developer solution. Resultantly to this control of the separation of the two plates, the proximity of the medium's photoconductive surface to a one plate, and the strength of the electric field between that plate and the photoconductive surface, is also controlled. By the control the thickness and density of the applied toner film is maintained constant, and a high quality image is maintained, despite depletion of toner from the developer solution. The toner concentration is preferably sensed as electrical resistance. A control circuit responsive to this sensed resistance preferably includes an analog-digital converter, a microprocessor, a stepper motor driver/controller, and a stepper motor rotating a cam. The cam rotation varies the separation between the two plates. The useful life of the developer solution for imaging is typically extended by a factor of at least two.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.