Abstract: A method by which the target of a toner concentration (TC) sensor can be set up based on the equivalent developability concept without using an expensive patch generator. First, use a black toner area coverage (BTAC) sensor to measure the relative reflectance (RR) of a 100% area coverage developed patch (ROS generated) at a series of development levels (Vem or Vdev) to generate a pseudo development curve and estimate VdO in real-time (VdO is the Vdev level that starts to develop toner onto the photoreceptor belt.) Then, add a nominal delta Vdev to VdO to get the development level (Vdev) needed to generate 100% area coverage gray patch. Finally, using a BTAC sensor to measure the RR level of a 100% area coverage (AC) gray patch, move the target of the TC sensor, and converge the sensor's reading to the sensor's target continuously until the RR level of the gray patch hits the RR target (predefined) within the tolerance range. Thus, the target of the TC sensor is set for the xerographic system automatically.

Abstract: A method of using toner concentration (TC) as an active actuator in the tonal reproduction curve (TRC) controller, so that not only will the TRC controller maintain the TRC of the output, but also all the electrostatic actuators will not diverge, and the toner concentration will be within the latitude range of the xerographic system. The process ensures that the target of the toner concentration (TC) sensor will be changed properly in direction (up/down) and amplitude to compensate the TRC output of the print engine based on either reflective reactance readings and/or the level of the electrostatic actuators.

Abstract: A method of controlling the solid developed mass per unit area and the tone reproduction curve in a printing machine by reading data from a sensor, comparing the data to an acceptable range of data values, where the data is not within the acceptable range of data values, updating a plurality of control actuators, determining whether the discharge ratio is within an acceptable range of discharge ratio values, where the discharge ratio is within the acceptable range of discharge ratio values, applying new control actuators to a power supply in the printing machine, and where the discharge ratio is not within the acceptable range of discharge ratio values, adjusting raster output scanner exposure per an exposure formula.

Abstract: In a hybrid jumping (HJD) or hybrid scavengeless (HSD) development station used in xerography, a control system avoids arcing conditions in a gap between a donor member and an image receptor. In a set-up operation, a series of test patches are produced while incrementing the AC amplitude in the gap. A change in reflectivity of the patches as a function of the AC amplitude in the gap is measured and the actual width of the gap is thus estimated. An accurate estimate of the gap width can then be used in a control algorithm.

Abstract: A method and apparatus are provided to calibrate a xerographic print engine toner concentration sensor to accurately control the toner concentration to a specified operating target. At least two control patches are imaged onto a photoreceptor. Each patch has a different voltage level where the voltage levels are the difference between the exposure discharge voltage and the developmental roll voltage. The relative reflectivity of each patches is obtained. The latent patches are repeatedly developed at different toner concentrations. The reflectivities of the patches formed at the same toner concentration are combined to obtain a combined reflectivity for that toner concentration. As a result, a toner concentration curve is obtained that has an improved response relative to the toner concentration curves that correspond to each of the individual voltage levels.

Abstract: A real-time photo-induced discharge curve (PIDC) model generator uses a nonliner model structure based on the physics of a xerographic system photoreceptor. The PIDC generator estimates a small number of parameters in the PIDC model in real-time for a given xerographic system configuration. The estimated PIDC may be used by xerographic system process controls, diagnostics and xerographic system setup in real-time.

Abstract: A method and apparatus are provided to calibrate a xerographic print engine toner concentration sensor to accurately control the toner concentration to a specified operating target. At least two control patches are imaged onto a photoreceptor. Each patch has a different voltage level where the voltage levels are the difference between the exposure discharge voltage and the developmental roll voltage. The relative reflectivity of each patches is obtained. The latent patches are repeatedly developed at different toner concentrations. The reflectivities of the patches formed at the same toner concentration are combined to obtain a combined reflectivity for that toner concentration. As a result, a toner concentration curve is obtained that has an improved response relative to the toner concentration curves that correspond to each of the individual voltage levels.