Toner concentration sensing system for an electrophotographic printer
AssigneeXerox Corporation
InventorThomas A. Henderson
Life of this patent
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Abstract
A system controls the concentration of toner in developer in an electrophotographic printer. Toner is applied on a test patch on a charge-retentive surface in a manner consistent with a desired toner density on a test patch, and the actual toner density on the test patch is measured. The charge applied to the charge-retentive surface is then adjusted in response to the measured actual toner density to obtain the desired toner density on a subsequent test patch. The change in charge applied to the charge-retentive surface is used to detect a shortage of toner in the developer.
Claims6
A method of controlling toner concentration in a quantity of developer material used in an electrophotographic printer including means for applying toner to an electrostatic latent image on a charge-retentive surface by creating an electrostatic development field of a preselected magnitude, comprising the steps of:
- creating an electrostatic charge of predetermined magnitude on an area of the charge-retentive surface, therby creating a test patch in the area;
- electrostatically applying toner in a manner consistent with a desired toner density on the test patch;
- measuring the actual toner density on the test patch to indicate a measured toner density;
- changing the magnitude of the development field in response to the measured toner density, to obtain the desired toner density on a subsequent test patch;
- and
- causing a quantity of toner to be added to the quantity of developer material in response to the development field being changed to exceed a predetermined magnitude.
A system for controlling toner concentration in a quantity of developer material used in an electrophotographic printer including means for applying toner to an electrostatic latent image on a charge-retentive surface, comprising:
- means for applying an initial charge to the charge-retentive surface;
- means for creating a electrostatic charge of predetermined magnitude on an area of the charge-retentive surface, therby creating a test patch in the area;
- means for electrostatically applying toner in a manner consistent with a desired toner density on the test patch, said means for electrostatically applying toner creating an electrostatic development field of a preselected magnitude;
- means for measuring the toner density on the test patch to indicate a measured toner density;
- means for changing the magnitude of the electrostatic development field in response to the measured toner density, to obtain the desired toner density on a subsequent test patch;
- and
- means for causing a quantity of toner to be added to the quantity of developer material in response to the magnitude of the electrostatic development field being changed to exceed a predetermined magnitude.
Dependencies are inferred from the claim text.