Abstract: A characterization procedure for the a detector in a toner patch sensor of an electrophotographic image forming device is performed with the toner patch sensor operatively connected to the image forming device's power supply. During the characterization procedure, a gain setting is determined that produces a predetermined target output from the toner patch sensor based on electromagnetic radiation reflected from a reference reflectivity sample. Subsequently, a toner patch is generated by the image forming device and a reflectance of the toner patch is measured based on the gain setting, with the toner patch sensor operatively connected to the power supply. The measurement(s) may then be used to adjust at least one electrophotographic image forming parameter. More than one reference reflectivity sample may be used, with corresponding gain settings stored in the image forming device.

Abstract: Methods and devices for operating a toner patch sensor in an electrophotographic image forming device. A characterization procedure for a light detector in the toner patch sensor may use one or multiple reflectance standards. A gain setting is determined that produces a predetermined target output from the toner patch sensing circuit for each of the standards. The characterization procedure may be carried out at a test bench or with the toner patch sensor installed in the corresponding device.

Abstract: A method of compensating for mechanical and magnification errors affecting toner density control in an image forming device is described herein. The method includes directing light towards a toner test surface, sensing the resulting reflections, and buffering the density data corresponding to the sensed reflections during a predetermined test window. The method may compensate for mechanical and magnification errors associated with the toner test pattern by processing the buffered density data to adjust the location of the data collection windows corresponding to the toner test patterns. For example, the buffered density data may be processed to detect first and second boundary patterns disposed on the toner test surface within the test window, determine a time differential between the first and second boundary patterns, and adjust the location of the data collection windows based on the determined time differential and a nominal expected time differential.

Abstract: A characterization procedure for the a detector in a toner patch sensor of an electrophotographic image forming device is performed with the toner patch sensor operatively connected to the image forming device's power supply. During the characterization procedure, a gain setting is determined that produces a predetermined target output from the toner patch sensor based on electromagnetic radiation reflected from a reference reflectivity sample. Subsequently, a toner patch is generated by the image forming device and a reflectance of the toner patch is measured based on the gain setting, with the toner patch sensor operatively connected to the power supply. The measurement(s) may then be used to adjust at least one electrophotographic image forming parameter. More than one reference reflectivity sample may be used, with corresponding gain settings stored in the image forming device.

Abstract: Methods and devices for operating a toner patch sensor in an electrophotographic image forming device. A characterization procedure for a light detector in the toner patch sensor may use one or multiple reflectance standards. A gain setting is determined that produces a predetermined target output from the toner patch sensing circuit for each of the standards. The characterization procedure may be carried out at a test bench or with the toner patch sensor installed in the corresponding device.

Abstract: A method of compensating for mechanical and magnification errors affecting toner density control in an image forming device is described herein. The method includes directing light towards a toner test surface, sensing the resulting reflections, and buffering the density data corresponding to the sensed reflections during a predetermined test window. The method may compensate for mechanical and magnification errors associated with the toner test pattern by processing the buffered density data to adjust the location of the data collection windows corresponding to the toner test patterns. For example, the buffered density data may be processed to detect first and second boundary patterns disposed on the toner test surface within the test window, determine a time differential between the first and second boundary patterns, and adjust the location of the data collection windows based on the determined time differential and a nominal expected time differential.

Abstract: Drive train motor speed is varied in a manner that compensates for characteristic rotational velocity errors of the associated drive train, such as by modulating a drive train motor speed control signal at a modulation phase and amplitude derived from the characterized rotational velocity error. Characterization can be performed on a test system for each drive train of interest, and the compensation values thus obtained can be saved for later use by systems in which the characterized drive trains are used. Thus, a drive train used in a consumables cartridge for an electrophotographic printing (EP) system can be characterized and the corresponding data saved via a label or memory circuit that is affixed to the cartridge. Such data can be used by the EP system in which the cartridge is installed to more accurately control the velocity of the image forming process members driven by the cartridge's characterized drive train.

Abstract: An image processing apparatus including tandem print engines is provided for forming an image on an image receiving substrata. The apparatus includes a first print engine and a second print engine downstream from the first print engine. The second print engine is slaved to the first print engine. The first print engine has a first photoreceptor and a first period of revolution. The second print engine has a second photoreceptor and a second period of revolution. The image processing apparatus further includes an intermediate inverter that inverts the image receiving substrate between the first print engine and the second print engine. The inverter determines a phase difference between a first seam signal from the first photoreceptor and a second seam signal from the second photoreceptor.

Abstract: An image processing apparatus including tandem print engines is provided for forming an image on an image receiving substrata. The apparatus includes a first print engine and a second print engine downstream from the first print engine. The second print engine is slaved to the first print engine. The first print engine has a first photoreceptor and a first period of revolution. The second print engine has a second photoreceptor and a second period of revolution. The image processing apparatus further includes an intermediate inverter that inverts the image receiving substrate between the first print engine and the second print engine. The inverter determines a phase difference between a first seam signal from the first photoreceptor and a second seam signal from the second photoreceptor.

Abstract: Drive train motor speed is varied in a manner that compensates for characteristic rotational velocity errors of the associated drive train, such as by modulating a drive train motor speed control signal at a modulation phase and amplitude derived from the characterized rotational velocity error. Characterization can be performed on a test system for each drive train of interest, and the compensation values thus obtained can be saved for later use by systems in which the characterized drive trains are used. Thus, a drive train used in a consumables cartridge for an electrophotographic printing (EP) system can be characterized and the corresponding data saved via a label or memory circuit that is affixed to the cartridge. Such data can be used by the EP system in which the cartridge is installed to more accurately control the velocity of the image forming process members driven by the cartridge's characterized drive train.

Abstract: A method of aligning a print image of an electrophotographic machine, the method including the steps of determining a power level of a laser beam, sensing a synch position of the laser beam associated with the scan line and varying a delay time before starting the scan line dependent upon the power level and the synch position.

Abstract: A photoconductive member for use in a single pass multi-color printing machine is disclosed. The photoconductive member is composed of an inter seam zone having a physical seam. The inter seam zone includes one of a plurality of image-on-image registration marks respective to a particular color latent image formed on the photoconductive member in a single pass. A plurality of interdocument zones is also included on the photoconductive member wherein process control marks are formed. While the inter seam zone is used for monitoring color-to-color registration, the process control marks are monitored to adjust the timing of the printing machine so that copy media synchronizes with an asynchronous placement of the images on the photoconductive member. A single pass, multi-color electrophotographic printing machine architecture uses a vertically oriented photoconductive belt. Transfer of the toner powder images occur at the lowermost portion of the photoconductive belt.

Abstract: A photoconductive member for use in a single pass multi-color printing machine is disclosed. The photoconductive member is composed of an inter seam zone having a physical seam. The inter seam zone includes one of a plurality of image-on-image registration marks respective to a particular color latent image formed on the photoconductive member in a single pass. A plurality of interdocument zones is also included on the photoconductive member wherein process control marks are formed. While the inter seam zone is used for monitoring color-to-color registration, the process control marks are monitored to adjust the timing of the printing machine so that copy media synchronizes with an asynchronous placement of the images on the photoconductive member. A single pass, multi-color electrophotographic printing machine architecture uses a vertically oriented photoconductive belt. Transfer of the toner powder images occur at the lowermost portion of the photoconductive belt.

Abstract: Transfer belt subassembly for a color printer includes a transfer belt, home position indicator, temperature sensor, and memory. The transfer belt subassembly is measured and characterized after fabrication, before being installed in a printer. Measurement and calibration data for the transfer belt is stored in memory as part of the subassembly, including data representing velocity characteristics of the transfer belt and temperature compensation factors used by an engine-controller in a method to govern the speed of the drive motor. When the transfer belt subassembly is inserted into a printer, the engine-controller is operative in response to data stored in the memory and sensed belt velocity and temperature data, providing adjustment of belt velocity and compensation for variations in the transfer belt speed. Using the predetermined characterizing data, precise alignment of the color planes with respect to one another is achieved for accurate color printing.

Abstract: A method of printing with an electrophotographic machine includes providing a first optical sensor for sensing a start-of-scan position of a laser beam produced by a scanning laser printhead and transmitting a first position signal indicative thereof A second optical sensor senses an end-of-scan position of the laser beam produced by the scanning laser printhead and transmits a second position signal indicative thereof A temperature of the scanning laser printhead is measured with a temperature sensing device. A plurality of positions of each of the first optical sensor and the second optical sensor are empirically determined at each of a plurality of values of the temperature of the scanning laser beam printhead.

Abstract: Color imaging methods and systems are provided where each color separation image is to be registered in a composite manner under a variety of machine conditions. Registration sensors are provided to register the color separations under a variety of machine conditions while accounting for the different types of registration sensors used. A controller calibrates the registration sensors automatically based on set-up data and, using the calibrated sensors, controls the output of the image data for one or more of the color separation images to reduce or eliminate image registration offsets. The registration sensors are calibrated by directly measuring set-up marks during set-up. Each registration sensor outputs a feedback to the controller during set-up to account for phenomenon caused by variation in toner concentration or sensor susceptibility. The registration sensors provide a plurality of set-up sensor feedback values, one for each of at least four colors and one for a bare photoreceptor belt.

Abstract: A transfer belt subassembly for a color printer includes a transfer belt, a home position indicator, a temperature sensor and a memory. The transfer belt subassembly is measured and characterized after it fabrication and before being installed in a printer. The measurement and calibration data for the transfer belt is stored in the memory that is part of the subassembly. The memory stores data representing the velocity characteristics of the transfer belt and temperature compensation factors for use by a engine-controller of the printer to govern the speed of the drive motor. When the transfer belt subassembly is inserted into a printer, the engine-controller is operative in response to data stored in the memory and sensed belt velocity and temperature data to provide adjustment of belt velocity and compensation for variations in the transfer belt speed. By use of the predetermined characterizing data, precise alignment of the color planes with respect to one another is achieved for accurate color printing.

Abstract: A belt drive module and a corresponding method includes or employs a belt that moves along a path, at least one support roller or other structure that supports the belt as it moves along the path, a drive roller that effects movement of the belt along the path, a tension roller that applies a tension force to the belt in order to maintain engagement of the belt with the drive and/or support rollers, at least one processing station (e.g., an image processing station) disposed along the path that performs a process relative to a predetermined position of the belt, and a torque assist drive that applies a torque assist force Td at a location between the drive roller and the tension roller. Torque assist may be provided by a current limited DC motor or by a constant torque friction clutch applied to a roller, e.g., a stripper roller of an electrophotographic imaging system. Advantageously, the torque assist force Td facilitates accurate positioning of the belt (e.g.

Abstract: A belt drive module and a corresponding method includes or employs a belt that moves along a path, at least one support roller or other structure that supports the belt as it moves along the path, a drive roller that effects movement of the belt along the path, a tension roller that applies a tension force to the belt in order to maintain engagement of the belt with the drive and/or support rollers, at least one processing station (e.g., an image processing station) disposed along the path that performs a process relative to a predetermined position of the belt, and a torque assist drive that applies a torque assist force Td at a location between the drive roller and the tension roller. Torque assist may be provided by a current limited DC motor or by a constant torque friction clutch applied to a roller, e.g., a stripper roller of an electrophotographic imaging system. Advantageously, the torque assist force Td facilitates accurate positioning of the belt (e.g.

Abstract: In color printing with a color registration system for the registration of plural color images on an image bearing surface, such as a photoreceptor belt of a color printer, registration marks are imaged on the image bearing surface, which registration marks correspond to the color images and are sensed by a registration marks sensor. In an initial gross registration mode the system first automatically images first registration marks, in the form of expanded chevron targets, which are greatly expanded in the process direction so as to avoid overlapping marks even if there is initial gross misregistration, to thus provide wider initial misregistration latitude for the sensor. When an acceptable initial registration is achieved, the system automatically switches to imaging more closely spaced and more frequent second registration marks, preferably regular chevron targets, providing higher registration accuracy.