Abstract: An imaging device includes a photoconductive drum charged by a charge roll and opposed by developer roll. The developer roll adds toner to the drum to develop a latent image on the drum for transfer to media or an intermediate transfer member at a transfer roll. One or more high voltage power supplies communicate with a controller to set voltages on the rolls. During times of non-imaging, but rotation of the drum, the charge roll charges the drum to less than a Paschen breakdown voltage of the drum. A voltage of the transfer roll is determined that corresponds to a temperature and relative humidity of an operating environment of the imaging device and the developer roll is charged based thereon. The charge of the transfer roll is set close to the charge of the drum, but higher in magnitude. A laser may also discharge the drum.

Abstract: An imaging system having methods for reducing churn in an imaging device which includes identifying a number of unproductive revolutions made in a print engine of the imaging device, determining whether the number of unproductive revolutions exceeds a predetermined threshold, and performing at least one of: using a predetermined speed limit when printing a page and disabling a function in the imaging device upon the determination that the number of unproductive revolutions exceeds the predetermined threshold.

Abstract: An imaging device includes a photoconductive drum charged by a charge roll and opposed by a transfer roll to transfer an image from the drum. The drum becomes biased to a negative voltage by setting charges of negative voltage on both the charge roll and transfer roll. A controller switches the bias of the transfer roll to a positive voltage from the negative voltage and a delta or difference in a charge of the drum is determined from before and after the switching. Based on the delta, the voltage on the charge roll is boosted by a boost voltage to improve the charge on the drum. In this way, deteriorating or defective charge rolls can be still used to charge the drum to a proper voltage for imaging. Techniques for determining the delta, the boost and the magnitude of voltage charges are further embodiments.

Abstract: An imaging device includes a photoconductive drum charged by a charge roll and opposed by a transfer roll to transfer an image from the drum. The drum becomes biased to a negative voltage by setting charges of negative voltage on both the charge roll and transfer roll. A controller switches the bias of the transfer roll to a positive voltage from the negative voltage and a delta or difference in a charge of the drum is determined from before and after the switching. Based on the delta, the voltage on the charge roll is boosted by a boost voltage to improve the charge on the drum. In this way, deteriorating or defective charge rolls can be still used to charge the drum to a proper voltage for imaging. Techniques for determining the delta, the boost and the magnitude of voltage charges are further embodiments.

Abstract: An electrophotographic imaging device having a method of printing which includes determining whether a duty cycle state in the imaging device has changed; selecting one of a full toner density calibration and a partial toner density calibration based on the determining; performing the one of the full toner density calibration and the partial toner density calibration; identifying a toner density to be applied during printing as a result of the performing; developing a toned image having a toner density equal to the toner density identified; and printing the toned image on a media sheet, wherein the full toner density calibration is skipped upon at least a determination that the duty cycle state has remained the same.

Abstract: An electrophotographic imaging device having a method of printing which includes determining whether a duty cycle state in the imaging device has changed; selecting one of a full toner density calibration and a partial toner density calibration based on the determining; performing the one of the full toner density calibration and the partial toner density calibration; identifying a toner density to be applied during printing as a result of the performing; developing a toned image having a toner density equal to the toner density identified; and printing the toned image on a media sheet, wherein the full toner density calibration is skipped upon at least a determination that the duty cycle state has remained the same.

Abstract: An electrophotographic imaging device having a method of printing which includes determining whether a duty cycle state in the imaging device has changed; selecting one of a full toner density calibration and a partial toner density calibration based on the determining; performing the one of the full toner density calibration and the partial toner density calibration; identifying a toner density to be applied during printing as a result of the performing; developing a toned image having a toner density equal to the toner density identified; and printing the toned image on a media sheet, wherein the full toner density calibration is skipped upon at least a determination that the duty cycle state has remained the same.

Abstract: An electrophotographic imaging device having a method of printing which includes setting a default toner density for printing; developing a first toned image having the default toner density; printing the first toned image on a first page of a print job; and before printing a second page of a print job, determining whether a duty cycle state of a photoconductive member in the imaging device has changed, and upon a positive determination, developing a second toned image having a toner density derived from the default toner density and printing the second toned image on the second page.

Abstract: A method and apparatus for handling a time based error condition in an imaging apparatus. The method includes transporting a first media sheet from the media input tray towards the transfer nip of the imaging apparatus; and determining, when the first media sheet reaches a predetermined point in the media path, whether the print engine of the imaging apparatus is ready to transfer a first image of the plurality of images to the media sheet at the transfer nip. Upon a determination that the print engine is not ready, the first media sheet is transported through the transfer nip without transferring the first image thereto, until the first media sheet is placed in the output area, and a second media sheet is transported to the transfer nip, a first image is transferred to the second media sheet and the second media to sheet is transported to the output area.

Abstract: A method and apparatus for handling a time based error condition in an imaging apparatus. The method includes transporting a first media sheet from the media input tray towards the transfer nip of the imaging apparatus; and determining, when the first media sheet reaches a predetermined point in the media path, whether the print engine of the imaging apparatus is ready to transfer a first image of the plurality of images to the media sheet at the transfer nip. Upon a determination that the print engine is not ready, the first media sheet is transported through the transfer nip without transferring the first image thereto, until the first media sheet is placed in the output area, and a second media sheet is transported to the transfer nip, a first image is transferred to the second media sheet and the second media sheet is transported to the output area.

Abstract: Data may be obtained in the form of a printer control density table from a memory within a replacement toner cartridge. The cartridge may include parity bits to ensure the accuracy of the data.

Abstract: The presence of a photoconductor drum in a laser printer may be determined by making electrical measurements without directly sensing drum presence. In some embodiments, this may be done without using any added printer components.

Abstract: A printing device (10) such as a laser printer includes a fuser assembly (200) with a fuser wiper (210) that can be removed and replaced by a user during normal maintenance to extend the useful life of the fuser assembly (200). Indicators (b0, b1) stored in a memory device (144) can be read by a print engine (36) of a printer (10) either when a print cartridge (100) is first inserted into the printer (10) or at specified times thereafter. Depending on the contents of the memory device (144), the print engine (36) may send a notification message to the printer's raster image processor (150) to cause a message to be displayed on the printer's operational/display panel (254) that informs a user the fuser wiper (210) should be replaced.

Abstract: A system, method and article for adjusting the time interval between feeding of successive sheets of media in a printer or copier. The method comprises initiating a first pick signal for a sheet of the media and identifying a feed time for the sheet of media, and identifying an expected feed time for said media. The system compares feed times to an expected feed time and adjusts according to such comparison to substantially correct for slippage or other problems feeding diverse media.

Abstract: Printer has a standby state in which the motor driving the laser scanning mirror is turned off immediately after a print job when another page is not ready. To increase operating speed, a signal to the printer starts a timer (Ready timer). When a page is printed, the timer is started and only when it reaches zero is the motor turned off. When data of a page is received by the printer and the Ready timer is non-zero, a sheet is immediately picked for printing.

Abstract: The number of pages of a print job received at printer (10) is determined (256). If the number of pages is low, printing is conducted at intermediate speed (262). If the number of pages is higher, printing is conducted at high speed (254). If the number of pages is not known, a default is selected (260). The default often will be to print at intermediate speed because most jobs are short. If high speed printing is in progress when a job is received, the next job is printed at high speed (254). Alternatively, a predetermined number of the first pages of a job may be printed at intermediate speed.

Abstract: An improved variable speed fan controller for use in devices such as laser printers. The controller automatically adjusts its output signal to fans such that a fan quickly settles into an appropriate operating speed, even if the fan has been newly installed into the equipment. The controller can store values in non-volatile memory, if desired, to keep track of recent changes in the fan's operating parameters and corresponding control signal values. The controller is able to control relatively inexpensive fans that don't necessarily operate at a predictable fan rotating speed under repeatable conditions and control signals, by controlling the fan to an initial or predetermined rotating speed; if the fan isn't running within a suitable range of rotational speeds, then determining whether a fine or coarse adjustment should be made to the fan's rotational speed. The controller makes appropriate adjustments until the fan's rotational speed is within acceptable operating tolerances.

Abstract: Control (P) of imaging device (1) senses the period of time sensor (17) senses media (5) at input feed roller (16a). When a too-long-over-sensor condition is sensed, drive of input feed roller (16a) is terminated by operation of clutch (C). A feed roller (19a) farther in the media path continue to operate. One sheet of media (5) is fed while a dual fed sheet is held in the nip of feed roller (16a) and idle roller (16b). Subsequently, feed roller (16a) is again driven to feed the dual fed sheet for normal imaging.

Abstract: A laser printer having a rotating mirror (116) and a heat fuser (220) is operated with a sequence of standby conditions. At the end of a print job mirror (116) is continued to be rotated at printing speed while the temperature of fuser (220) is reduced somewhat. This is maintained for a short time, after which the speed of rotation of mirror (116) is reduced significantly and the fuser (220) 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.

Abstract: Before warm-up of a printer, sheets are initially fed for printing based on a normal assumed lock time for rotation of polygonal mirror (116) of a laser printhead (100). After an initial printing when in a mode in which the printer is warmed, such as a standby mode, sheets are fed for printing based on a lock time shorter than the normal lock time. When a lock time failure is observed when using the shorter lock time, use of the longer lock time is resumed. Time to begin printing is improved by the use of the shorter lock time.