Lexmark International, Inc.

Marc Cousoulis

Michael Craig Leemhuis

Ronald Willard Baker

Gary Scott Overall

Courtney Harrison Soale

Gregory Lawrence Ream

Niko Jay Murrell

Edward Alan Rush

Hrishikesh Pramod Gogate

Calvin Dale Murphy

Alexander Johannes Geyling

Michael Brian Bacelieri

Matthew Russell Smither

Michael Charles Day

David William Shuman

Travis Alan Riggs

William Claiborne Ryle

Kweku Korsah

Jared Kouhui Lin

An imaging device has a developer roll to provide toner to a photoconductive drum to develop a latent image on the drum for direct transfer to media or an intermediate transfer member. A power supply in communication with a controller sets relative voltages on the developer roll and drum. During transfer of the toner, the imaging device determines a current between the developer roll and drum. In turn, the controller determines a charge and mass of the toner for setting with the power supply an operating voltage on the drum or developer roll. Preventing and reporting toners with insufficient charge are other embodiments.

Electrophotographic control in imaging devices, including sensing current between a developer roll and drum pertaining to current of a latent image and a paschen breakdown

A color imaging device includes a plurality of developer rolls with a common operating point, such as a common operating voltage. To determine the operating point, an acceptable range of color density is determined for each toner, the range being lighter and darker than an optimum color density for that toner. A search range is devised such that values within the range are examined relative to deviations from the optimum color density per each toner. The common operating point is selected as that having the lowest deviation per all toners. Also, if the common operating point corresponds to a color density darker than the acceptable range of color density for any toner, additional halftoning occurs compared to traditional halftoning, such as for continuous tones or solids. In this way, four color developer rolls can be operated from a single power supply, yet still provide acceptable color images.

Color image density calibration in imaging device having common developer voltage

An imaging device has a photoconductive drum with a surface that is selectively discharged to create a latent electrostatic image for attracting toner for transfer to a media moving in a process direction. The image is divided into multiple segments along the process direction and discharged pixels per segment are counted. An accumulator keeps track of the numbers of pixels per revolutions of a roller that applies the toner to the drum. Upon meeting a predetermined deficiency in the counts of pixels in any given segment, an artificial image gets generated on the surface of the photoconductive drum that supplies the missing pixels, per segment. The image gets developed with toner, but does not transfer to the media. Lubrication occurs on the surface of the drum and each segment retains a relatively common number of imaging pixels that get developed over time.

Lubricant metering for photoconductor in imaging device

A method of controlling toner development during a life of an imaging unit in an image forming device by determining whether an end of life of the imaging unit has been reached and upon a positive determination, performing at least one of incrementally lowering a target toner mass to be measured by a toner patch sensor and incrementally reducing the magnitude of voltage biases applied to at least one of the magnetic roll and the charging roll of the imaging forming device. Performing the acts of incrementally lowering and reducing are repeated until the imaging unit is replaced. The method reduces the risk of damage to the image forming device due to carrier bead development while allowing for printing to occur.

Systems and methods for controlling toner development in an image forming device

A method and system are disclosed for detecting a fatal error condition in a printing device having an intermediate transfer member for facilitating toner transfer, including sensing a reflectance value of the intermediate transfer member at a first predetermined time; comparing the sensed reflectance value at the first period of time to a predetermined threshold; sensing a reflectance value of the intermediate transfer member at a second predetermined time after the predetermined first time; and comparing the sensed reflectance value of the intermediate transfer member at the second period of time to the predetermined threshold. If each of the sensed reflectance value at the first predetermined time and the sensed reflectance value at the second predetermined time is greater than the predetermined threshold, the method includes selectively suspending further printing operations until the imaging device is serviced.

Imaging device with diagnostic testing for fatal errors

A method of controlling toner concentration in an image forming device by determining a charge per unit mass of toner in a mixture of toner and carrier and adding toner to the mixture if the charge per unit mass of the toner is higher than a predetermined threshold. Other methods and devices are disclosed.

Charge slope derivation control of toner concentration

The present invention relates to an apparatus and method that is capable of adjusting the position of a developing agent metering device. Developing agent may therefore be metered in an image forming device.

Toner metering device

A device to regulate toner within an image forming apparatus. The regulating member has a first section and a toner regulating edge with at least one gap. The regulating member controls the amount of toner that is distributed on the surface of the toner developer roller by contacting the toner developing roller in a contact region. The gap, having at least one upper edge, may regulate toner on the toner developer roller near the contact region. The toner regulating device may prevent inadvertent toner marks that may appear on printed media.

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Lexington, KY, United States of America

Marc Cousoulis