Abstract: The dielectric thickness of a photoreceptor is determined in a variety of ways, including using a relationship between threshold voltage and dielectric thickness, using a relationship between dielectric thickness and the difference between biased transfer roller (BTR) voltage and photoreceptor surface potential, using a relationship between dielectric thickness and biased charging roller (BCR) impedance, using a relationship between dielectric thickness and the slope of the DC current vs. voltage curve for the BTR or the BCR, and using a relationship between dielectric thickness and the BTR voltage at zero current. The threshold voltage can be found by using the slope of the BCR DC current vs. voltage curve, measuring photoreceptor surface potential for a plurality of target values below the charging knee to obtain the intercept value, or finding the actual value of the charging knee. A method of using the BCR as an electrodynamic voltmeter is also disclosed.

Abstract: Xerographic photoreceptor life is improved while maintaining output print quality by adjusting the AC charging actuator of a xerographic machine to a point at which photoconductor life is optimized while maintaining output print quality. Where the actuator is voltage, the actuator is set a predetermined amount above the knee voltage of the photoreceptor surface potential versus peak-to-peak voltage curve, which is determined during operation of the machine. Instead of determining the knee voltage, calibration sheets can be generated for various values of the actuator, the best sheet with the least possible actuator value is selected, and the AC charging actuator is set to the value corresponding to the best sheet. The sheets can be evaluated by a user, or an optical array sensor can be used to scan the sheets so that the controller can compare the sheets to stored criteria to automatically select the best sheet and set the actuator.

Abstract: Exemplary embodiments provide a direct imaging system and methods for direct marking an image using the system. The disclosed direct imaging system can eliminate the creation of a latent image and can be used in an electrophotographic machine and related processes. Specifically, the direct imaging system can include a direct marking substrate (e.g., a printing substrate) and a development belt member closely spaced from the direct marking substrate. In one embodiment, the development belt member can include a plurality of actuator cells with each actuator cell controllably addressable to eject one or more toner particles adhered thereto. The ejected toner particles can transit the space between the donor belt member and the direct marking substrate, and directly marking onto the direct marking substrate forming an image.

Abstract: Exemplary embodiments provide a direct imaging system and methods for direct marking an image using the system. The disclosed direct imaging system can eliminate the use of at least one of a charge, and/or exposure subsystems in an electrostatographic machine and related processes. Specifically, the direct imaging system can include a direct marking substrate (e.g., a printing substrate) and a development roll member closely spaced from the direct marking substrate. In one embodiment, the development roll member can include a plurality of actuator cells with each actuator cell controllably addressable to eject one or more toner particles adhered thereto. The ejected toner particles can transit the space between the donor roll member and the direct marking substrate, and thereby marking onto the direct marking substrate forming an image.

Abstract: Exemplary embodiments provide a digital development system and methods for making and using the system. Specifically, the digital development system can utilize a roll member that includes a plurality of actuator cells arranged in a 2-dimensional array with each actuator cell having an actuator membrane individually addressable to eject one or more toner particles adhered thereto. In addition, the digital development system can utilize an imager architecture that includes an addressing logic circuit connected to each cell to selectively control the ejection of the one or more toner particles onto an image receiving member that is closely spaced from each actuator membrane. The disclosed digital development system can be used for non-interactive development systems for image-on-image full-color printing similar to HSD (Hybrid Scavengeless Development) technology with the donor roll becoming a high quality silent imager.

Abstract: Exemplary embodiments provide a roll member that includes one or more linear arrays of actuator cells and methods for making and using the roll member. In one embodiment, each linear array of the roll member can be controllably actuated as a group by, e.g., an oscillating voltage, to release toner particles adhered thereto and to form a uniform toner cloud in the development area between the roll member and an image receiving member. The controllable actuation can also aid in the unloading process of the residual toner particles from the roll member. In various embodiments, the uniform toner cloud and/or the controllable unloading process can enable a non-interactive development system for image-on-image full-color printing.

Abstract: Exemplary embodiments provide a roll member that includes one or more controllable cells and methods for making and using the roll member to control an image (or toner) state thereon. The controllable cells can be disposed on a roll substrate and configured in a manner that each controllable cell can be addressed individually and/or as groups. Each controllable cell can be addressable to provide a surface vibration to release toner particles adhered/attracted thereto and can also be capable of sensing the toner state of the roll member and thus to control the image or toner state. In an exemplary embodiment, the disclosed roll member can be used as a donor roll for a development system of an electrophotographic printing machine to create controlled and desired toner powder cloud for high quality image development.

Abstract: A color management system is provided for enabling imaging of selected colors called spot colors by dynamically adjusting the normal printer gamut to achieve a color gamut extension. Developed toner mass may be increased or decreased by changing ROS laser intensity. Such adjustment can occur on a pixel-by-pixel basis for within page and within sections of the image gamut extension.

Abstract: The presently described embodiments relate to improving system productivity where maintenance purge routines are required through use of a digital front end (DFE) job scheduler. This approach utilizes knowledge of future jobs to maximize productivity. So, even if a low coverage area job is being processed, and a purge routine is scheduled, the purge routine may be avoided. This is achieved by projecting the system evolution over a future time horizon and determining the schedule of toner purge events (a non productive dead cycle) to minimize a cost function that penalizes the purge event (dead cycling and material loss should be minimized) and the deviation of average toner resident time in the sump from some desired set point of range. In this regard, knowledge that a high coverage area job is downstream and average toner residient time may be advantageously used to effectively perform the purge itself while in productive mode.

Abstract: The dielectric thickness of a photoreceptor is determined in a variety of ways, including using a relationship between threshold voltage and dielectric thickness, using a relationship between dielectric thickness and the difference between biased transfer roller (BTR) voltage and photoreceptor surface potential, using a relationship between dielectric thickness and biased charging roller (BCR) impedance, using a relationship between dielectric thickness and the slope of the DC current vs. voltage curve for the BTR or the BCR, and using a relationship between dielectric thickness and the BTR voltage at zero current. The threshold voltage can be found by using the slope of the BCR DC current vs. voltage curve, measuring photoreceptor surface potential for a plurality of target values below the charging knee to obtain the intercept value, or finding the actual value of the charging knee. A method of using the BCR as an electrodynamic voltmeter is also disclosed.

Abstract: Xerographic photoreceptor life is improved while maintaining output print quality by adjusting the AC charging actuator of a xerographic machine to a point at which photoconductor life is optimized while maintaining output print quality. Where the actuator is voltage, the actuator is set a predetermined amount above the knee voltage of the photoreceptor surface potential versus peak-to-peak voltage curve, which is determined during operation of the machine. Instead of determining the knee voltage, calibration sheets can be generated for various values of the actuator, the best sheet with the least possible actuator value is selected, and the AC charging actuator is set to the value corresponding to the best sheet. The sheets can be evaluated by a user, or an optical array sensor can be used to scan the sheets so that the controller can compare the sheets to stored criteria to automatically select the best sheet and set the actuator.

Abstract: A development subsystem is used to develop developer having semiconductive carrier particles and toner particles. The development subsystem includes a developer housing, for retaining a quantity of developer having semiconductive carrier particles and toner particles, a first magnetic roll having a stationary core with at least one magnet and a sleeve that rotates about the stationary core of the first magnetic roll, a second magnetic roll having a stationary core with at least one magnet and a sleeve that rotates about the stationary core of the second magnetic roll, and a motor coupled to the first and the second magnetic rolls to drive the rotating sleeves of the first and the second magnetic rolls in a direction that is against the direction of a photoreceptor that rotates in proximity to the first and the second magnetic rolls. The first and the second magnetic rolls carry semiconductive carrier particles and toner particles through a development zone formed by the first and the second magnetic rolls.

Abstract: A system and method for correcting a defect in an image, such as a ghost defect or a reload defect, by compensating for the defect.

Abstract: The presently described embodiments relate to improving system productivity where maintenance purge routines are required through use of a digital front end (DFE) job scheduler. This approach utilizes knowledge of future jobs to maximize productivity. So, even if a low coverage area job is being processed, and a purge routine is scheduled, the purge routine may be avoided. This is achieved by projecting the system evolution over a future time horizon and determining the schedule of toner purge events (a non productive dead cycle) to minimize a cost function that penalizes the purge event (dead cycling and material loss should be minimized) and the deviation of average toner resident time in the sump from some desired set point of range. In this regard, knowledge that a high coverage area job is downstream and average toner residient time may be advantageously used to effectively perform the purge itself while in productive mode.

Abstract: A defect analysis system for a xerographic print engine includes a residual mass sensor that senses the two-dimensional signature structure of residual mass remaining on a photoconductive or other substrate surface after image transfer. Preferably, the sensor is a full width array that spans substantially an entire width of the photoconductive surface. This information is then processed and analyzed to determine a specific type of transfer defect present. This may include the quantified level of defect for each detected type. The defect analysis system may also include a closed-loop control system that can adjust various xerographic process parameters using feedback based on the identification and optionally magnitude of each specific defect type. The identified print quality defect, such as mottle, streaks, point deletions, graininess, etc.

Abstract: An electrostatic printing machine having a development station having a toner dispenser for dispensing toner in the development station and wherein the electrostatic printing machine employs a method for improving xerographic stability of condition the development station, including reviewing a print job comprising job images for toner usage; calculating a dispense rate base on the toner usage, print job attributes, and sensing toner quantity that is present; comparing the calculated dispense rate to a predefined minimum dispense rate; and if the calculated dispense rate is less than the predefined minimum dispense rate, setting the toner dispenser to the predefined minimum dispense rate; the setting includes scheduling a detone process if the toner mass in the development station exceeds a predefined threshold value.

Abstract: A toner concentration control system for maintaining image quality in a developer structure, the toner concentration control system comprising: a transfer efficiency estimator for measuring a transfer efficiency estimate associated with a developed image on an imaging surface before and after transfer; and a toner dispenser, responsive to said transfer efficiency estimator, for adjusting a toner dispense rate.