Lexmark International, Inc.

David Kurt Klaffenbach

Thomas Campbell Wade

Gary Allen Denton

Kevin Dean Schoedinger

Harald Portig

Philip Jerome Heink

Craig Palmer Bush

Gerald Lee Fish

Timothy A Green

Mohsen Marefat

A laser printer includes at least three laser beams for simultaneously scanning a rotatable recording medium. The laser beams have their centers spaced uniform or non-uniform distances from each other. The centers of the laser beams are spaced predetermined distances from each other so that the print resolution may be 300, 400, 600, or 1,200 dpi depending upon the laser beams selected for use with at least two laser beams always being selected.

Laser printer having variable beam spacing

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

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

Mirror (1) of a laser printhead has an octagonal outer configuration. During normal use the mirror is rotated at high speed, which drives ambient air which causes noise. To control the noise a shroud (11) surrounds the mirror and confines the air except at an opening in the shroud to permit a laser beam to reach the mirror and be reflected out. A rib extends over the mirror and near the area of the opening, positioned to reduce sounds created by the assembly.

Sound reduced rotatable polygon assembly

A low-noise, paper pick or other single cycle mechanism is obtained by employing a rotary solenoid (15) which has a force to a detent position which may be overcome by force from a drive roller (1). In the detent position the drive roller faces a blank sector (5) of a gear (3) which is integral with a shaft (7), which is the shaft to be turned. An electrical control signal to the solenoid rotates gear (3) through gear (13), which is directly driven by the solenoid, and which turns gear (11) on the shaft. The drive gear overcomes the force of the solenoid until it is disengaged after one cycle, at which time the detent force of the solenoid holds the mechanism in its detent position.

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Versailles, KY, United States of America

David Kurt Klaffenbach