Lexmark International, Inc.

Thomas Campbell Wade

Gary Scott Overall

Cyrus Bradford Clarke

Phillip Byron Wright

Douglas Anthony Able

David Anthony Schneider

Earl Dawson Ward, Ii

Daniel Eugene Pawley

Brian Edward Cooper

Brian Wesley Damon

Daniel George Mlejnek

David Kurt Klaffenbach

Paul Athanasius Robinson

Kevin Dean Schoedinger

Benjamin Keith Newman

Gregory Lawrence Ream

Harald Portig

David Lee Merrifield

James Francis Webb

Christopher Dane Jones

James Douglas Gilmore

Philip Jerome Heink

Douglas Campbell Hamilton

James J Molloy

Daniel Paul Cahill

Craig Palmer Bush

Steven L Applegate

David John Mickan

Louann Behymer Samuels

Curtis Duane Woodson

Timothy P Craig

William Joseph Thornhill

Mark Edwin Kirtley Lund

Michael Kurt Gordon

Charles Jerome Cheek

Thomas Gregrory Survant

Chad Michael Plening

George Peter Olson

Gregrory Lawrence Ream

An electronic locking system to secure consumable items in an image forming device and a method therefore. In one embodiment of the invention, an electronic locking system to secure media sheets includes a media tray to hold media sheets, a tray receiving member for receiving the media tray, and a controller. The tray receiving member includes a drive device and a plunger. The plunger is moved by the drive device between a locked and an unlocked position. The controller is configured to control the drive device to move the plunger to engage a portion of the media tray in the locked position and to move the plunger to disengage from the portion of the media tray in the unlocked position. The electronic locking system, incorporating the controller, provides an effective and efficient way to lock/unlock the media tray and eliminates the use of mechanical keys.

Electronic locking system to secure consumable item in an image forming device and a method therefor

A printer that stores a minimal number of unadjusted stochastic threshold arrays in non-volatile memory, in which the unadjusted threshold arrays are used to generate adjusted threshold arrays at run time by use of special parameterized transfer functions. The unadjusted array for a particular color is stored in the printer's ROM and preferably is stored in a packed configuration to save memory space. The parameterized transfer functions are used to convert the unadjusted threshold data into adjusted threshold data for each color and type of print media. These parameterized transfer functions are stored in the printer's non-volatile memory, and take up very little memory space. In a preferred embodiment, the unadjusted threshold array comprises a 128 row by 128 column sized array, and each element of this array comprises a 10-bit number. When a parameterized transfer function is applied to this unadjusted array, the resulting numeric values for the adjusted array elements are produced as 8-bit numeric values. The greater precision in the originating unadjusted array provides more perceptual levels of intensity (i.e., color brightness), which is particularly important at the lighter shades of each color. The adjusted threshold arrays add only the number of dots per gray level (i.e., per differential threshold array level) that are required to provide a printer response that very nearly approximates the human eye perceptual differential response of intensity.

Method for correcting unadjusted threshold arrays for halftoning by use of parameterized transfer functions that generate adjusted threshold arrays at run time

An entrance guide for externally fed sheet () to printer () is configured to bow the sheets. In one embodiment guides () within slothave upper and lower configurations which force sheet into a bow. In one embodiment slot () is bowed and is sufficiently narrow in height to only accept a bowed sheet. The bowed sheets do not sag against the printer (), which aids in sheet registration.

Sheet feeder avoiding sheet sag

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

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. After each periodic determination, PELslice clock timing pulses are selectively inserted into or removed from the PELslice clock timing pulses for all of the write lines but the write line, which is closest to the desired length, to increase or decrease their lengths to be substantially equal to the write line, which is closest to the desired length. The time for insertion or removal of each of the PEL slices into the train of PELslice clock timing pulses produced by the PELslice clock is determined with each preferably inserted at a non-active portion of a PEL. Each insertion or removal of a PEL slice also may be offset from its determined position.

Electronic control arrangement for a laser printer

A single aligning roller is disposed at angle to each of two reference barriers to which a printed sheet is to be advanced so as to be aligned at a specific location for stapling. The aligning roller exerts a greater force towards the reference barrier further from the adjacent edge of the printed sheet to be aligned. The aligning roller is preferably at 66&deg; to the reference barrier further from the adjacent edge of the printed sheet to be aligned.

Finisher with single roller for frictionally moving each sheet

Method and apparatus for correcting unadjusted threshold arrays for halftoning by use of parameterized transfer functions that generate adjusted threshold arrays at run time

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 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 printer is provided which includes a series of analog delay elements that operate at a very fast speed, and therefore, can be used in an enhanced mode to further subdivide the slice clock to create a greater variety of gray levels that can be used in continuous tone printing. By using this enhanced mode of continuous tone printing, a full 'on' slice can be immediately preceded or followed by a partial slice, under the control of the series of delay elements. The delay elements are automatically calibrated at the beginning of each page to be printed by placing the delay line chain circuit into a 'calibrate mode,' during which time a clock pulse is provided to the delay line chain so that the chain is repeatedly tested, in increments of one additional delay element at a time, to determine the number of delay elements that are required to cause a time delay that is greater than or equal to the period of the slice-based clock. Once that quantity is determined, the calibrated delay elements will be used to print the entire next page to be output from the laser printhead. As the printer desires various gray levels for continuous tone printing, the number of whole slices and partial slices for a particular pel or group of pels will be determined by the desired gray level, and when a partial slice is to be printed, the printer will select the appropriate number of delay elements that will be used to control a flip-flop that outputs the 'video output' signal to the laser printhead. When the asynchronous 'reset' input of the flip-flop has a control signal applied, the output of the flip-flop will immediately change state to truncate the 'on time' of the slice that was currently being output to the laser printhead. By use of the asynchronous reset flip-flop, the slice can be subdivided into smaller time intervals, completely under the control of the delay line chain without regard to the frequency or phase angle of the pel clock or the slice-based clock.

Method and apparatus for calibrating delay lines to create gray levels

A high resolution speed control for a DC or BLDC phase-locked-loop (PLL) motor is provided. A phase accumulator sends a time varying frequency reference to the PLL input, where the average frequency sets the motor speed with a high degree of accuracy. A post divider is used to reduce the number of circuits required to implement the function.

Motor drive system controlled by a phase accumulator and method therefor

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 achieving line-to-line synchronization having a high degree of synchronization accuracy. Synchronization is performed by a specific high-speed block of logic which signals the beginning of scans to a PELCLK-based logic at pel boundaries, and provides sub-pel shifting as it passes data between the pel generation logic and a laser control signal. The synchronization error is made as small as propagation delays through a single multiplexer element. Such delays can be controlled to values less than 1/2 ns. The need to stop and restart the clocks is eliminated. All complex pel generation logic is clocked with the relatively low frequency PELCLK without regard to the synchronization task.

Method and apparatus for HSYNC synchronization

Compensation for beam separation of multiple laser beams of a laser printer simultaneously scanning a photoconductor drum is automatically made. The time for the lead beam to travel a predetermined distance is ascertained and then the separation time between the lead beam and one of the remaining beams is determined. When using only one light sensor, the time for the lead beam to travel the predetermined distance is the scan time of the lead beam. When using two light sensors, the time for the lead beam to travel the predetermined distance is the time for the lead beam to travel between the two light sensors, which define the predetermined distance, in the same scan. This determination of the time for the lead beam to travel the predetermined distance and its separation time from another of the remaining beams is continuously made for all of the remaining beams even during printing. If the beam separation time of each of the remaining beams from the lead beam is large enough for the one light sensor to generate distinct pulses for the lead beam and any one of the remaining beams during the same scan, the separation time for any one of the laser beams can be directly measured in only one scan.

Method and apparatus for aligning multiple laser beams

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Lexington, KY, United States of America

Thomas Campbell Wade