Abstract: In-situ measurements are made by a toner area coverage sensor on test patches from a single control dot screen developed on a cleanable surface and are observed by a photoreceptor. The density of patches for other dot screens is estimated from the measured density of the control dot screen error of each measured patch by using a scaling factor, which is different for each separation and patchy density. This error is then added to the target tone reproduction curve (TRC) for each non-control dot screen to give an estimated density for each of the other dot screens. The TRC are then developed/updated using the estimated patch densities for each of the other dot screens. This substantially reduces the amount of toner and processing resources utilized.

Abstract: A user of an image forming device selects from among a plurality of pre-stored color rendition dictionaries (CRDs) in order that a set of system process parameter setpoints associated with that CRD may be referenced to bias and/or skew an available color gamut in the direction of a particular nominally out-of-gamut color which the user wishes to produce in a color image output by the image forming device. A capability is included in a color image forming device store and/or update multiple sets of special process parameter setpoints defining a plurality of CRDs each of which may be identified and associated with a specific color in order that requests to print out-of-gamut colors may be satisfied routinely as exceptions to a nominal gamut based on a nominal set of stored setpoints when a CRD is selected and the setpoints associated with that CRD are input for reference by the color image forming device on a temporary basis.

Abstract: A method and system for a color xerographic machine determines a lower bound for the ROS power levels so that color defects are not produced by light attenuation from one or more layers of toner particles on a latent image. The method computes a minimum ROS power level for the photoreceptor at its maximum and minimum charge levels. The minimum ROS power level is the level at which the discharge voltage does not drop beyond a maximum discharge voltage difference. The difference is related to a toner particle density that affects color reproduction. The minimum ROS power levels for the minimum and maximum photoreceptor charge levels are used to compute a functional relationship for minimum ROS power levels at other photoreceptor charge levels. Thereafter, the minimum ROS power level function may be used to compute minimum ROS power levels for other photoreceptor charge levels. The computed minimum ROS power levels may be used to control the power levels used during color reproduction performed by the machine.

Abstract: An enhanced toner area coverage (ETAC) sensor may be calibrated to adjust for changes in LED intensity by determining a functional relationship between specular developed mass per unit area (DMA) values and diffuse readings obtained from the sensor. Specular and diffuse readings are obtained from an ETAC sensor that senses reflected light from toner patches generated with incrementally increasing densities on the photoreceptor belt. The specular readings in a particular range and their corresponding diffuse readings are selected for the calibration computations. Reflected ratios are computed from the specular readings and used to determine specular DMAs. The specular DMAs and selected diffuse readings define a set of points for which a functional relationship is determined.

Abstract: An in situ system and method for setting the charge voltages in a dual recharge color photocopier device includes a calculating an optimal DC grid voltage for each DC charging device of the dual recharge photocopier device. With the AC charging devices off, the photoreceptor belt is advanced to the first color station at a uniform residual voltage level. The DC charge device for the first color station charges the photoreceptor belt to a uniform voltage level. An non-contact voltmeter measures and stores the value read from the photoreceptor belt. An exposure device at the first color station exposes a portion of the photoreceptor belt to be read by the voltmeter at the next color station. The process continues through each color station, reading the voltage level of the portion of the photoreceptor belt exposed at the previous color station until voltage readings have been obtained for each color station.