Image Forming Apparatus Calibration with Speed-Specific Lookup Tables
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Solution Overview
Problem
The increasing difference in process speeds in image forming apparatuses leads to significant variations in image gradation, causing user trouble and increased process time, especially when using a common lookup table across multiple speeds.
Innovation Solution
The implementation of a dual control system for calibration, where the first system requires a recording medium for initial lookup table creation and the second system adjusts this table dynamically without a medium, allowing for frequent updates and reducing user burden and time, by measuring density values at different speeds and creating modification tables for each speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common lookup table is used across multiple process speeds, then device complexity is reduced, but manufacturing precision deteriorates due to significant gradation differences at different speeds
Solution Approach 1:
The patent segments the calibration system into two distinct parts: a common lookup table for basic density correction and speed-specific modification tables for gradation correction. This segmentation allows the system to maintain a simple base structure while adding targeted corrections for different process speeds, resolving the contradiction between device complexity and manufacturing precision.
Solution Approach 2:
The patent applies local quality by making the modification tables speed-specific rather than uniform across all speeds. Each process speed has its own modification table tailored to its specific gradation characteristics, allowing precise correction for each speed while keeping the overall system relatively simple through the shared lookup table.
2Manufacturing precision
If calibration is performed for each process speed separately, then manufacturing precision is improved, but loss of time increases proportionally with the number of speeds
Solution Approach 1:
The patent implements preliminary action by creating a common lookup table in advance that handles the fundamental density correction for all process speeds. This preliminary calibration reduces the subsequent calibration workload for each specific speed, as only modification tables need to be created rather than complete lookup tables, thereby reducing calibration time while maintaining precision.
Solution Approach 2:
The patent applies partial action by focusing calibration efforts only on the specific aspects that differ by speed (gradation correction through modification tables) rather than recalibrating all parameters for each speed. This partial recalibration approach maintains manufacturing precision while significantly reducing the time investment required compared to full recalibration.
3Productivity
If the process speed is increased to improve productivity, then productivity is improved, but manufacturing precision deteriorates due to larger speed differences causing greater gradation variations
Solution Approach 1:
The patent implements dynamics by making the calibration system adaptive to different process speeds through speed-specific modification tables. As the process speed changes, the system dynamically selects and applies the appropriate modification table, allowing high-speed operation with maintained precision. This dynamic adaptation resolves the contradiction between productivity and manufacturing precision.
Data Source
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AI summary
An image forming apparatus comprises a reader, converting means configured to convert image signal based on a conversion condition, image forming means configured to form an image based on the converted image signal, transfer means configured to transfer the image onto a recording medium, first generation means configured to control the image forming means to form a test pattern at a first image forming speed, control the transfer means to transfer the test pattern onto a recording medium, and generate a first conversion condition based on reading data, wherein the reading data is output from the reader, measuring means configured to measure a measurement image, and second generation means configured to control the image forming means to form a first measurement image at the first image forming speed, control the image forming means to form a second measurement image at a second image forming speed different from the first image forming speed, control the measuring means to measure the first measurement image and the second measurement image, and generate a second conversion condition based on the first conversion condition, a measurement result of the first measurement image, and a measurement result of the second measurement image, wherein the converting means converts an image signal based on the first conversion condition in a case where the image forming means forms an image at the first image forming speed, and wherein the converting means converts an image signal based on the second conversion condition in a case where the image forming means forms an image at the second image forming speed.