Image Processing Apparatus Toner Amount Control
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Solution Overview
Problem
Conventional toner total amount control methods in color printers result in signal distortion and loss of information due to non-linear relationships between density values and toner amounts, leading to degradation of image quality and gradation characteristics.
Innovation Solution
An image processing apparatus and method that includes a first conversion unit to convert signal values into toner amounts, a control unit to manage these amounts based on a limit value for each pixel, and a second conversion unit to output the appropriate signal values, preventing unnecessary toner total amount control processing and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If toner total amount control processing is performed by converting density values to toner amounts using LUT, then the total amount of toner can be controlled within the limit value, but information is lost due to non-linear relationship causing signal distortion and degradation of image quality
Solution Approach 1:
The image data processing is segmented into two distinct paths: a first path for pixels where the total toner amount does not exceed the limit value (maintaining original density values), and a second path for pixels where the total toner amount exceeds the limit value (applying toner amount control). This segmentation prevents unnecessary processing and information loss in pixels that do not require control.
Solution Approach 2:
Instead of applying toner total amount control processing to all pixels, the invention applies the control processing only to the extent necessary - specifically, only to pixels where the total toner amount would exceed the limit value. This partial action approach maintains image quality by avoiding unnecessary conversions and information loss in pixels that are already within acceptable limits.
2Reliability
If density values are converted to toner amounts and back using LUT for all pixels, then toner total amount control is achieved, but gradation characteristics degrade due to repeated non-linear conversions
Solution Approach 1:
The processing is divided into segments based on whether toner control is needed: pixels requiring control undergo conversion through LUT, while pixels not requiring control bypass the conversion process entirely. This segmentation preserves gradation characteristics in pixels where control is unnecessary.
Solution Approach 2:
The invention applies the minimum necessary processing - only converting density values to toner amounts and back for pixels that actually exceed the toner limit. This partial application of conversion processing minimizes degradation of gradation characteristics while still achieving toner control where needed.
Data Source
AI summary
An apparatus comprises: a first conversion unit configured to convert a first signal value serving as an output signal of each of a plurality of color materials into a value indicating an amount of each of the plurality of color materials; a control unit configured to control the value indicating the amount of each of the plurality of color materials based on a limit value for a total amount of the plurality of color materials for each pixel; and a second conversion unit configured to convert the value indicating the amount of each of the plurality of color materials that is controlled, into a second signal value serving as a corresponding output value, wherein when the total amount of the plurality of color materials based on the first signal value is not larger than the limit value in a pixel of interest, the control unit outputs the first signal value.