Patent ID: 6147698
Filing Date: 2000-11-14
Classification: G03G,H04N

Abstract:
A method for controlling a density of a printed image on a medium of a printer comprising the steps of:providing a printer comprising a memory device, an optical sensor, a control processor, and printer control parameters selected from the group consisting of: light exposure, toner concentration and bias voltage;printing a control strip on the print medium having a bias patch and a density patch, wherein each of said patches has different standard optical density;measuring an optical density of said bias patch and said density patch;determining a bias tolerance limit for said bias patch and a density tolerance limit for said density patch;calculating a new bias voltage and a corrected optical density of said density patch using the following equations if the optical density of said bias patch is not within said bias tolerance limit of said bias standard optical density:VB.sub.NEW =VB.sub.OLD -(CBVOD*(BIASSTD-BIAS))DENCOR=DENSTD-DENSITY+CBVOD*(VB.sub.NEW -VB.sub.OLD)wherein said V.sub.NEW is the new bias voltage, VB.sub.OLD is the measured bias voltage of said printer, CBVOD is an experimentally determined constant, BIASSTD is the bias standard optical density, BIAS is the optical density of the bias patch, DENCOR is the corrected optical density of said density patch, DENSTD is the standard optical density of said density patch, and DENSITY is the optical density of the density patch;calculating a new light exposure setting (LDA.sub.NEW) and a new toner concentration setting (TC.sub.NEW) of said printer using the following equations if the corrected optical density of the density patch is not within said density tolerance limit of the standard optical density of the density patch: ##EQU16## wherein PCTCORR is a real number between 0 and 1, CBVOD, CLDA, CTCO are experimentally determined constants, LDA.sub.OLD is a measured light exposure, and TC.sub.OLD is a measured toner concentration; andadjusting the voltage bias setting of said printer to VB.sub.NEW, adjusting the light exposure setting of the printer to LDA.sub.NEW and adjusting a toner concentration setting of the printer to said TC.sub.NEW value.