How Printers Save Toner by Dropping Light-Colored Pixels
A Ricoh patent for printers that save toner by completely ignoring very light pixels and using a special dot pattern for darker ones.
Original patent title: “Image forming apparatus having a function of saving developing agent”
A Ricoh patent for printers that save toner by completely ignoring very light pixels and using a special dot pattern for darker ones. Granted to Ricoh Co Ltd in 2002 with 14 claims and 9 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
This technology manages how a printer uses toner to create an image. It evaluates the darkness of each pixel against a specific threshold. If a pixel is lighter than that threshold, the printer does not print it at all, saving toner. If the pixel is darker than the threshold, the printer uses a Pulse Width Modulation (PWM) pattern, which turns the laser on and off multiple times within a single pixel space to use less toner while still representing the image.
The gap
What does this patent NOT cover?
- Does not cover methods that reduce toner by globally lowering the laser intensity for the entire page.
- Does not cover color-based toner saving that adjusts ink density based on hue rather than pixel brightness.
- Does not cover software-based image processing that happens on a computer before the data reaches the printer.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The patent treats 'toner saving' as a binary decision per pixel: either skip it entirely if it is too light, or apply a specific micro-pattern if it is dark enough to be worth printing.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Toner save mode on office laser printers
Draft print settings in enterprise document management systems
Why it matters
The bigger picture
This patent addressed the high cost of toner in office environments during the early 2000s. By intelligently dropping light pixels, printers could significantly extend the life of a toner cartridge without requiring the user to manually adjust image contrast or quality settings.
Filed
September 4, 2001
Granted
November 5, 2002
Market context
Who's building on this
Companies in this space
Ricoh remains a major player in this space, integrating these types of power and material-saving algorithms into their enterprise multifunction printers. Other major manufacturers like HP and Canon utilize similar PWM-based toner optimization techniques in their standard print drivers.
Market impact
This patent helped standardize 'Draft' or 'Toner Save' modes in office hardware. It moved the responsibility of toner management from the human user to the printer's internal firmware, making cost-saving features a standard expectation for office equipment.
Claim 1 — Plain English
What this patent covers
This technology manages how a printer uses toner to create an image. It evaluates the darkness of each pixel against a specific threshold. If a pixel is lighter than that threshold, the printer does not print it at all, saving toner. If the pixel is darker than the threshold, the printer uses a Pulse Width Modulation (PWM) pattern, which turns the laser on and off multiple times within a single pixel space to use less toner while still representing the image.
The clever bit
The patent treats 'toner saving' as a binary decision per pixel: either skip it entirely if it is too light, or apply a specific micro-pattern if it is dark enough to be worth printing.
What it does not cover
- Does not cover methods that reduce toner by globally lowering the laser intensity for the entire page.
- Does not cover color-based toner saving that adjusts ink density based on hue rather than pixel brightness.
- Does not cover software-based image processing that happens on a computer before the data reaches the printer.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Early stage
Citation count
20/40
Early citations
Claim breadth
9/20
Moderate scope
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$10K – $32K
Midpoint $20K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
14 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Enami, E. (2002). How Printers Save Toner by Dropping Light-Colored Pixels (U.S. Patent No. 6,476,836). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/6476836/image-forming-apparatus-having-a-function-of-saving-developing-agent
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Printers Save Toner by Dropping Light-Colored Pixels cover?
A Ricoh patent for printers that save toner by completely ignoring very light pixels and using a special dot pattern for darker ones.
Who owns patent US 6476836?
Ricoh Co Ltd owns this patent, granted in 2002.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 6476836 cited by?
This patent has been cited by 9 later patents that build on its ideas.
What problem does this patent solve?
This patent addressed the high cost of toner in office environments during the early 2000s. By intelligently dropping light pixels, printers could significantly extend the life of a toner cartridge without requiring the user to manually adjust image contrast or quality settings.
What does this patent NOT cover?
Does not cover methods that reduce toner by globally lowering the laser intensity for the entire page.
Patent monitoring