Lexmark International, Inc.

Cyrus Bradford Clarke

Phillip Byron Wright

Thomas Campbell Wade

David Brian Langer

Christopher Dane Jones

Douglas Anthony Able

Thomas Austin Fields

William Paul Cook

Kevin Dean Schoedinger

James Douglas Gilmore

Douglas Campbell Hamilton

Craig Palmer Bush

Benjamin Keith Newman

Randall David Mayo

Gregory Lawrence Ream

David Lee Merrifield

Gary Scott Overall

James J Molloy

Peter E Wallin

Steven L Applegate

David John Mickan

Steven Wayne Parish

Allen P Johnson

Daniel George Mlejnek

Timothy P Craig

Brian Keith Bartley

Mark Edwin Kirtley Lund

Gregory John Sherwood

Matthew Lowell McKay

Thomas Wilbur Blanck

William Shannon Spencer

Charles Jerome Cheek

Thomas Gregrory Survant

William P Corbett

Jonathan Carey Frey

Gregrory Lawrence Ream

George Peter Olson

Laser beam scan line nonlinearity is compensated for by providing algorithms for generating linearity profiles which are used by a corresponding registration system in an electrophotographic device to determine the placement of Pels across a scan line.

Systems for performing laser beam linearity correction and algorithms and methods for generating linearity correction tables from data stored in an optical scanner

A method for associating a customer accessible supply item of a first type with an imaging apparatus includes communicating identification information between the customer accessible supply item of the first type and the imaging apparatus; and operationally locking the customer accessible supply item of the first type with only the imaging apparatus based on the identification information, to the exclusion of other imaging apparatuses and other customer accessible supply items of the first type.

Method for associating a customer accessible supply item with an imaging apparatus

The dynamic range of an electrophotographic device may be shifted by calibrating a laser power of a laser source to operate within a first range of power levels during a laser power adjustment operation. At least one laser control parameter is modified after calibrating the laser power so that the laser source is operable within a second range of power levels different from the first range of power levels and a beam emitted by the laser source is controlled within the second range of power levels when the beam is directed towards an image area of a photoconductive surface.

Systems and methods for adjusting the dynamic range of a scanning laser beam

Systems and methods are provided for characterizing laser beam process direction position errors in an electrophotographic device. Once the process direction position errors of a given beam laser beam system have been characterized, an image is adjusted or warped prior to being processed by the laser beam system to compensate for laser beam process direction position errors, e.g., bow and skew.

Algorithms and methods for determining laser beam process direction position errors from data stored on a printhead

A laser printer having a rotating mirror ( ) and a heat fuser ( ) is operated with a sequence of standby conditions. At the end of a print job mirror ( ) is continued to be rotated at printing speed while the temperature of fuser ( ) is reduced somewhat. This is maintained for a short time, after which the speed of rotation of mirror ( ) is reduced significantly and the fuser ( ) temperature is reduced significantly. This is maintained for a time, after which the mirror is no longer rotated (or, if practical, is rotated very slowly) and the fuser temperature is further reduced. At any time when a subsequent print job is received, the mirror and fuser are brought to printing state and the period of times are next started from a beginning state.

Printhead and fuser standby management

A printer has a media feed path (,) for feeding sheets of media (,), with the path having a side reference edge (,) for aligning the media. A media transport mechanism feeds the sheets of media at a standard speed and at a reduced speed. A narrow media detector (,) generates a narrow media signal when sheets of narrow media are fed through the media feed path. A controller (,) adjusts the media transport mechanism to feed the narrow media aligned with the reference edge at the reduced speed. A method of printing sheets of narrow media in a printer comprises the steps of aligning the narrow media with a reference edge in a media feed path of the printer, sensing when the narrow media are present in the media feed path, and feeding the narrow media through the media feed path at the reduced sheet feeding speed and, particularly with a belt fuser, with increased inter-sheet gap.

Printer for narrow media

An electrophotographic printing apparatus which eliminates overheating of the fuser belt when narrow gauge print media is utilized is disclosed. In this apparatus, a detection means determines whether a sheet of narrow gauge recording medium is being fed into the printer. When it is, the fuser heater is deactivated turned to a present lower temperature or is turned off when the narrow gauge recording medium exits the fusing nip. A preferred apparatus additionally contains means which measures the temperature of the heater once it is deactivated at predetermined intervals and, for each measurement, determines the amount of time required to bring the heater back up to the optimum fusing temperature. The preferred embodiment also includes a means for determining the amount of time it will take for the next piece of print media to travel from its current position to the fuser nip. This preferred embodiment then reactivates the heater when the time required to bring it back up to the fusing temperature is greater than or equal to the amount of time it will take the next piece of print medium to enter the fusing nip. This apparatus prevents overheating of the fuser belt which can accompany the use of narrow gauge print media. The application also discloses a method for fixing images using this apparatus.

Control of thermal heating in a belt fuser

An improved EP printer will automatically compensate for printer output darkness shift over the usage life of one or more components of the print engine. In many EP print engines, the printer output darkness without correction will gradually change as the components are used, and typically, the darkness will increase to an extent that is perceptible. The printer output darkness can be controlled using a EP operating point that changes certain operating parameters, such as the laser diode current, the duty cycle of the video data signals driving the laser diode, and other voltage parameters including the charge roller voltage, or the developer bias voltage. It is desirable to make adjustments over the usage life of these components, so as to maintain the initial printer output darkness throughout the life of the major system components. The adjustments can occur at periodic intervals based upon a metric that includes one or more of the following parameters: number of pels produced, number of pages printed, number of cycles of one or more components of the print engine, and/or the consumption of toner in grams. The adjustment information can be provided as look-up tables, or in the form of transfer functions. If look-up tables are used, the adjustment control algorithm could be one that interpolates between periodically-adjusted usage values stored in the look-up tables. Since many EP process cartridges tend to print darker rather than lighter over the life usage of that process cartridge, the present invention will accomplish two important goals by utilizing the methodology described above; not only will the printer output darkness be maintained at a substantially constant value, but the actual number of pels printed and pages printed will be increased by use of the same quantity of toner stored within the replaceable process cartridge.

Method and apparatus for compensating for a darkness shift during the life of an electrophotographic printer cartridge

An improved electrophotographic (EP) printer is provided having a detachable process cartridge that contains a non-volatile memory device, which is an EPROM that cannot be erased after a bit is burned. A 'toner wheel' mounted to the exterior of the toner reservoir of the process cartridge provides, in conjunction with an optoelectronic sensor, an electrical signal that the printer receives and uses to determine toner usage. A toner 'gas-gauge' is created which uses 'bucket levels' as discrete steps to indicate how much of the measured physical toner material actually remains within the toner reservoir. After a given amount of toner material has been dispensed through the developer unit, one of the bits of the EPROM memory device is irreversibly burned, thereby providing a permanent record on the process cartridge of a certain amount of toner usage. As with a normal automobile gas gauge, the toner gas-gauge reading should never increase unless the amount of toner material inside the toner reservoir has increased. Once the bucket level transitions begin to occur for the toner gas-gauge, the printer becomes aware that a majority of the toner material has been expended from inside the toner reservoir. If the number of bucket gradation levels then increases by more than the hysteresis amount, then the printer will 'lock out' the operation of a non-reusable process cartridge. When the lock-out mode occurs, a particular bit is burned on the EPROM mounted to the cleaner housing of the process cartridge. This ensures that this particular process cartridge cannot be removed, then simply placed back into the same (or a different) printer, and then begin supplying toner to a printer. Certain important 'machine data' also can be stored in the EPROM memory device on the process cartridge of the present invention. The present invention is also able to declare the 'end-of-life' of a process cartridge when the gas-gauge toner sensor is not functional (such as when it has been tampered with).

Method and apparatus for storing data in a non-volatile memory circuit

A method of determining an output level of an output stack of print media in an image forming apparatus. The print media is transported, one print medium at a time, to the output stack. A sensor positioned in association with the output stack senses when the output level of the output stack has reached a near full level. At least one physical characteristic of the print media is identified which can affect the stacking of the print media. The number of the print media transported to the output stack is counted after the near full level is sensed. A determination that the output level of the output stack has reached a full level is made, dependent upon each of the at least one physical characteristic and the counted number of the print media.

Method and system of sensing an output level of an output stack of print

A laser printer is provided having an automatic printhead identification system for use in a family of laser printers that are compatible with more than one model of printhead. For example, a single laser printer model can be made so that two different printheads can be successfully used, so long as the printer system knows which laser printhead has actually been installed. To detect which printhead has been installed, the printer operating system provides a reference clock signal having a pre-determined frequency, which dictates the rotational speed of the motor. Once the motor has achieved a 'lock' operational speed, the printer measures the scan rate of the faceted mirror by detecting the time interval between pulses of the 'HSYNC' signal. The HSYNC signal is sent to a 'divide-by-n counter' circuit which divides the pulse frequency of the HSYNC signal, thereby increasing the time interval (by a factor of 'n') that must be sensed by the system to determine which printhead is in fact installed. So long as the HSYNC 'lock' frequency is different between the various models of printheads that are compatible with a particular model laser printer, the principles of the invention can be used without adding any extra hardware sensors, signals, or memory addresses and detecting codes.

Method and apparatus for automatically determining the style printhead

The invention is directed to a method of calibrating a laser in an electrophotographic image forming apparatus used for producing a print image on a print medium. A laser having a selectively energizable laser beam output is provided. A rotatable optical device and the laser combine to define a movable projection path of the laser beam output. Rotation of the optical device results in movement of the projection path across a scan line overlaying a photoconductive drum. The optical device has a rotational acceleration upon initial rotation thereof with a ramp-up period during which the rotational velocity increases. A safe area is established in a portion of the scan line which does not overlay an image area on the photoconductive drum. The laser is energized and calibrated when the projection path is positioned in the safe area. The calibration is carried out during the ramp-up period of the rotating optical device.

Image forming apparatus with laser calibration during ramp-up period of

A laser printer (3) can initiate a line of printing only when the sweep of the laser light reaches a point in its cycle. An inkjet printer (5) moves paper by stepper motor in increments. Switch (9) senses the paper (15) to determine the location of paper in path (6) with respect to nominal printing locations of the laser printer. The closest nominal position is selected for printing. The paper may lead or lag the selected position. Switch (11) senses the paper to determine the location of paper in the path with respect to nominal printing locations of the inkjet printer. Two leads are added to reach a net greater lead, a lag is subtracted from a lead, and two lags are added to reach a net greater lag. The closest nominal position is then selected. This assures that registration does not vary by more than one half of the spacing between nominal locations of the second printer.

Registration of paper location for multiple printing

Printer (1) receives revised operating code in flash memory (19). To preserve offset adjustment unique to the printer, the values in new operating code are compared with those in the previous code, and new offsets preserving the previous offsets are stored in permanent memory (21). The use of permanent memory is minimized by basing the calculation on changes from start of production.

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Lexington, KY, United States of America

Cyrus Bradford Clarke