Abstract: A method of correcting plane-to-plane registration in an electrophotographic machine having a plurality of color planes includes the steps of printing a calibration pattern using each of the color planes; measuring at least one misregistration between the color planes on the calibration pattern; adjusting at least one top margin by setting a first time delay before a first line; adjusting one of a right margin and a left margin by setting a second time delay; determining a longest line length of the calibration pattern; and adjusting an other of the right margin and the left margin to match the longest line length.

Abstract: A method of correcting registration in an electrophotographic machine includes the steps of adjusting one of a right margin and a left margin by setting a time delay, determining a longest line length of a calibration pattern, and adjusting an other of the right margin and the left margin to match the longest line length.

Abstract: An optical system particularly useful for color laser printers. Four imaging systems are provided, one for each color, black, magenta, cyan and yellow. Each imaging system has separate pre-scan and post-scan optical assemblies. Two scanning polygons are provided, and each scanning polygon is shared by two imaging systems. Both pre-scan optical assemblies shared by each scanning polygon are provided on the same side of the scanning assembly at substantially similar mirror image angles, to reduce scan image registration errors. The pre-scan and post-scan optical assemblies have improved adjustability.

Abstract: The write lines of a color laser printer are maintained substantially equal throughout the printer's operation by an electronic control arrangement. At the factory, the write lines on all photoconductors of the color laser printer are calibrated to be substantially equal, and the ratio of each write line to a measuring line for each photoconductor is ascertained. During operation of the printer, the length of each of the measuring lines is periodically determined through counting the number of PELslice clock timing pulses produced from a PELslice clock operating at a fixed frequency determined during factory calibration. The length of the write line is determined by the product of the length of the measuring line and the factory calibrated ratio of the length of the write line to the length of the measuring line.

Abstract: A method of setting a plurality of margins in an electrophotographic machine includes setting a top margin for a reference color black by establishing a first time delay between a vertical synchronization signal and a first line. A right margin or a left margin for the reference color black is set by establishing a second time delay between a horizontal synchronization signal and a start of printing. The other of the right margin and the left margin is set by adjusting a scan speed of a laser beam across a photoconductive element and adjusting a process speed in the cross-scan direction including the speed of the photoconductive element, image accumulation member, and print medium. A bottom margin is set by adjusting the process speed. The other three color planes, cyan, magenta and yellow are then registered or aligned to the reference color plane, black.

Abstract: A method of aligning a laser printhead in an electrophotographic machine includes providing a fixture with a pair of fixed sensors. The fixed sensors are spaced apart along a length of a first fixture drum axis. Each of the fixed sensors is fixed relative to a second of the fixed drums. The first fixture drum is provided with a pair of floating sensors. The floating sensors are spaced apart along the length of the first fixture drum axis. Each of the floating sensors is fixed relative to the first fixture drum. A laser beam from the laser printhead is scanned across an outside surface of the first fixture drum, the fixed sensors and the floating sensors. An intersection of the scanned laser beam and the outside surface of the first drum defines a scan path. A first skew of the scan path relative to an axis of the first drum is measured using the floating sensors. A second skew of the scan path relative to an axis of the second drum is measured using the fixed sensors.

Abstract: A method of determining a position of a laser beam in an electrophotographic machine includes providing a sensor device having a laser beam receiving surface with a first edge and a second edge. The second edge is nonparallel to the first edge. The laser beam is scanned across the receiving surface in a scan direction perpendicular to a process direction. The laser beam intersects each of the first edge and the second edge of the receiving surface during the scanning. A time period between when the laser beam intersects the first edge and when the laser beam intersects the second edge of the receiving surface is measured. A process position of the laser beam along the process direction is calculated based upon the measured time period.

Abstract: An encoded device for a toner cartridge provides a plate having preprogrammed indicia positioned at locations defined in relation to a clock face. The preprogrammed indicia includes a start indicia positioned at about a 6:00 o'clock position and at least one measurement indicia located between about 200 degrees and about 230 degrees from the 6:00 o'clock position.

Abstract: The write lines of a color laser printer are maintained substantially equal throughout the printer's operation by an electronic control arrangement. At the factory, the write lines on all photoconductors of the color laser printer are calibrated to be substantially equal, and the ratio of each write line to a measuring line for each photoconductor is ascertained. During operation of the printer, the length of each of the measuring lines is periodically determined through counting the number of PELslice clock timing pulses produced from a PELslice clock operating at a fixed frequency determined during factory calibration. The length of the write line is determined by the product of the length of the measuring line and the factory calibrated ratio of the length of the write line to the length of the measuring line.

Abstract: An encoded wheel for a toner cartridge including a plate having preprogrammed indicia positioned at locations defined in relation to a clock face, the preprogrammed indicia including a start indicia positioned between about a 5:00 o'clock position and a 6:00 o'clock position, a stop indicia positioned at about a 9:00 o'clock position, at least one preselected cartridge characteristic indicia positioned between the start indicia and the stop indicia, and at least one measurement indicia located between about 200 degrees and about 230 degrees from said 6:00 o'clock position.

Abstract: An apparatus for correcting printhead skew in an electrophotographic machine. The electrophotographic machine includes a machine frame having a plurality of mounting locations, at least one printhead, and a plurality of resilient elongate beam members. Each of the plurality of resilient elongate beam members have a proximal end and a distal end, wherein each proximal end is attached to the printhead and each distal end is attached to a respective one of the mounting locations of the machine frame, thereby mounting the printhead to the machine frame. The printhead further includes a printhead base having a pivot axis defined, at least in part, by a location of attachment of said plurality of resilient elongate beam members. The apparatus further includes a skew adjustment mechanism for effecting a pivot of the printhead about the pivot axis.

Abstract: An electrophotographic imaging apparatus includes a plurality of photoconductive drums and a plurality of printhead assemblies. Each drum has an axis of rotation and a photoconductive peripheral surface. A plurality of the axes of rotation of the drums lie in a generally common plane. The peripheral surface of each drum rotates in a common direction defining an advance direction of the print medium. Adjacent drums are disposed at a first distance away from each other between the axes of rotation. Each printhead assembly is associated with a respective drum and is configured for generating a laser beam which impinges upon the respective drum along a line of incidence. The printhead assemblies are disposed at a second distance from one to another which is greater than the first distance.

Abstract: A method of reversing a laser beam in a machine includes orienting a pair of reflective surfaces at an angle of approximately 90° relative to each other. The laser beam is directed in a first direction such that the laser beam sequentially impinges upon a first of the reflective surfaces reflects off of the first reflective surface, impinges upon a second of the reflective surfaces, and reflects off of the second reflective surface in a second direction substantially parallel to and opposite the first direction. A pivot axis is substantially parallel to each of the reflective surfaces. Each of the reflective surfaces is pivoted about the pivot axis by a substantially equal angle to thereby change a position of the laser beam after reflecting off of the second reflective surface.

Abstract: One aspect of the invention is directed to a toner cartridge including a sump for carrying a supply of toner. An agitator is rotatably mounted in the sump, and the agitator has a first end and a second end. An encoded wheel is coupled to the first end of the agitator. The encoded wheel is structured and adapted to include a first preselected cartridge characteristic indicia having a first extent, a stop indicia having a second extent larger than the first extent and a start indicia having a third extent larger than the second extent. Each indicia may be in the form of a slot. Preferably, the start indicia is positioned between about a 5:00 o'clock position and a 6:00 o'clock position. The stop indicia is positioned at about a 9:00 o'clock position. At least one preselected cartridge characteristic indicia is positioned between the start indicia and the stop indicia.

Abstract: Method is disclosed for determining characteristics of a toner cartridge. One aspect is directed to determining the characteristics associated with a quantity of toner in the cartridge, and thus, the method includes the steps directed to determining a home position of an encoded device relative to a code reader, determining a delay in rotational movement of the encoded device with respect to a rotational movement of a drive mechanism as an agitator moves through the toner, and translating the delay into an amount of toner remaining in the cartridge. Another aspect is directed to determining preselected cartridge characteristics from the encoded device, and thus, the method includes steps directed to rotating the encoded device, reading a coding of the encoded device, and decoding the coding to determine the preselected cartridge characteristic information represented by the coding. The method steps directed to these aspects of the method may be performed separately or in aggregate.

Abstract: A cartridge for an electrophotographic machine having a sump for carrying an agitator rotatably mounted in the sump for engagement with a toner; an encoded device coupled to a first end of the agitator; and a torque sensitive coupling connected to a second end of the agitator which is connectable to a drive mechanism of the machine. The encoded device includes coding representing cartridge characteristic information.

Abstract: The amount of toner remaining in each toner cartridge (20a-20d) of a printer (1) is estimated by incrementing a count when one pel is detected in each small region of the bit map. The printer senses toner out, after which the scale ascribed to one count is revised to reflect the actual count to toner out. Specifically, the count to toner out becomes the number representative of empty so that one-half of that count is interpreted as half full. The remaining toner in each cartridge is displayed to the operator at a gauge (21).

Abstract: A release agent composition for use in an electrophotographic process is disclosed. This composition includes a specifically-defined heat-stable silicone oil-silicone wax random copolymer. The copolymer has a melting point such that it is liquid on the hot fuser roll, but solidifies at room temperature on the printed page. A random silicone copolymer, in the form of a paste or pliable caulk, which is useful for sealing leaks in toner cartridges is also disclosed. Finally, the method for preparing these copolymers is disclosed.

Abstract: An improved printer is provided that predicts how many pages can be printed before the toner or ink cartridge becomes empty, and also predicts how much time remains before this toner or ink cartridge becomes empty. This prediction is based upon the previous printing history of the printer while using this particular toner cartridge. After measuring the quantity of toner left in the toner cartridge, the printer of the present invention will display the approximate quantity of toner remaining in the cartridge on a screen of a host computer that is connected to the printer, either directly or through a network. The monitor screen of the host computer can also display the predicted number of pages remaining, based on the printer's previous usage history as described above.