Dynamic Color Drum Control for Black-Only Printing Wear Reduction
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Solution Overview
Problem
Existing methods for controlling the transfer of toned images in electrophotographic imaging devices, such as printers, either lead to unnecessary wear on color photoconductive drums during black-only printing or reduce throughput when transitioning between black-only and color printing.
Innovation Solution
A method where the imaging device identifies if a print job contains color images and adjusts the operation of color and black photoconductive drums accordingly, rotating only the black drum for black-only images and pausing or disengaging color drums when no color images are present to minimize wear and maintain throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the color motor is stopped and the ITM belt is allowed to slip between each nip formed between the color PC drums and a plurality of transfer rolls during black-only printing, then color supply consumption is reduced, but the charge on the surfaces of the color PC drums changes requiring rotation to be performed occasionally
Solution Approach 1:
The patent implements dynamic control of the color motor and ITM belt system, allowing the motor to operate in different states (running, stopped, or belt slipping) based on the printing requirements. This dynamic approach enables the system to reduce color supply consumption during black-only printing while maintaining the ability to quickly resume normal operation when color printing is needed, thus resolving the contradiction between reducing substance loss and maintaining productivity.
2Reliability
If the color PC drum is rotated occasionally while printing black pages to recharge and clean the drums, then the charge on the color PC drums is maintained, but the color toners are agitated causing EPAs to be knocked from carrier toner particles affecting toner performance
Solution Approach 1:
The patent extracts the harmful agitation effect by allowing the ITM belt to slip between the color PC drums and transfer rolls during black-only printing. This separation enables the PC drums to be recharged and cleaned without rotating the color toner cartridges, thus maintaining drum charge reliability while preventing EPA loss from toner particle agitation.
Solution Approach 2:
The patent segments the drum rotation function from the toner cartridge rotation function. The ITM belt can move independently to recharge and clean the PC drums without causing the color toner cartridges to rotate, thereby separating the beneficial drum maintenance function from the harmful toner agitation effect.
3Ease of operation
If each retracted transfer roll is moved towards the color imaging units to engage the ITM belt with the color PC drums when transitioning to color printing, then color printing can resume, but the sequence reduces throughput
Solution Approach 1:
The patent applies preliminary action by keeping the color motor in a ready state or pre-positioning the ITM belt system during black-only printing sequences. This allows for faster transition to color printing without requiring lengthy re-engagement sequences, thus maintaining ease of operation while minimizing throughput reduction during mode transitions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces wear on color photoconductive drums and improves printing efficiency by optimizing the operation of color and black imaging units based on the print job content, thereby extending the life of color toner supplies and enhancing printing performance.
Implementation Method 1
each color PC drum engageable with the ITM belt for depositing a color toned image when present to the outer surface of the ITM belt, a black imaging unit having a black PC drum and an associated black charging roll in contact therewith, the black PC drum engaged with the ITM belt for depositing a black toned image
Data Source
AI summary
A method for controlling transfer of black color toned images during simplex printing. The method comprises identifying a first image of a print job is a black-only image, determining whether or not the print job includes at least one color image, upon determining that the print job includes at least one color image, rotating only the black photoconductive (PC) drum and transferring a black-only toned first image thereon onto a rotating intermediate transfer member (ITM) belt and subsequently onto a surface of the media sheet at the image transfer roll, and moving color transfer rolls into engagement the color PC drums and pausing their rotation, and, upon determining that the print job does not include at least one color image, moving the color transfer rolls to disengage the ITM belt from the color PC drums and rotating only the black PC drum to sequentially transfer each remaining black-only toned image onto the ITM belt for printing on a surface of a corresponding next sequential media sheet at the image transfer roll.