Image Forming Apparatus Toner Density Detection Correction
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Solution Overview
Problem
Conventional image forming apparatuses cannot accurately adjust image forming conditions due to the lack of consideration for the change in transfer efficiency of detection toner images in response to the amount of toner transferred from the photoconductor drum to the output area at transfer timing.
Innovation Solution
The apparatus includes a transfer portion that transfers a detection toner image outside the output area, a detection portion that detects the density of the transferred toner image, a correction portion that adjusts the detection result based on the amount of toner transferred, and an adjustment portion that adjusts the image forming conditions accordingly, using a correction coefficient calculated from the amount of toner and electrical resistance of the intermediate transfer belt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detection toner image is transferred to the output area for density detection, then the detection is straightforward, but the transfer efficiency varies with the amount of toner transferred which compromises measurement precision
Solution Approach 1:
The patent extracts the detection toner image from the output area by transferring it to a separate detection area outside the output region. This allows density detection to be performed on a dedicated area without interference from the main image transfer process, eliminating the variability caused by changing toner amounts in the output area.
Solution Approach 2:
The patent segments the transfer belt into distinct functional areas: an output area for the main image and a separate detection area for density measurement. This spatial segmentation ensures that the detection process does not interfere with the output quality and that the detection area receives a consistent toner amount regardless of output area variations.
2Ease of manufacture
If the image forming condition is adjusted based on detected density without correction, then the adjustment process is simple, but the adjustment precision is compromised due to unaccounted transfer efficiency variations
Solution Approach 1:
The patent implements a feedback mechanism where the detected density of the detection toner image is used to calculate a correction coefficient, which then adjusts the image forming conditions. This closed-loop feedback ensures that transfer efficiency variations are continuously compensated, maintaining high precision without overly complicating the adjustment process.
Solution Approach 2:
The patent changes the parameter being measured by using a detection toner image with a known, fixed toner amount in the detection area. This allows the system to detect transfer efficiency variations as changes in optical density, which are then converted into correction coefficients for adjusting image forming conditions.
3Adaptability or versatility
If the detection area receives the same toner amount as the output area, then the detection reflects actual output conditions, but the detection precision is compromised due to variable toner distribution
Solution Approach 1:
The patent applies local quality by creating a detection area with specific, controlled properties: it receives toner from a dedicated exposure area with fixed toner amount, ensuring consistent detection conditions. This localized approach allows the detection area to have different toner characteristics than the output area, optimizing it specifically for precise density measurement.
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 approach allows for precise adjustment of image forming conditions, accounting for variations in toner transfer efficiency and electrical resistance, thereby improving the accuracy of image formation.
Implementation Method 1
a transfer portion, such as a primary transfer roller, that, upon receiving a supply of a predetermined transfer current, transfers a toner image formed on an image-carrying member
Implementation Method 2
The detection processing portion detects a density of the detection toner image that has been transferred to the transfer object
Data Source
AI summary
An image forming apparatus includes a transfer processing portion, a detection processing portion, a correction processing portion, and an adjustment processing portion. The transfer processing portion transfers a detection toner image to outside an output area of a transfer object to which a toner image as an output target is transferred from an image-carrying member. The detection processing portion detects a density of the detection toner image that has been transferred to the transfer object by the transfer processing portion. The correction processing portion corrects a detection result of the detection processing portion based on an amount of toner transferred from the image-carrying member to the output area at a transfer timing when the detection toner image is transferred. The adjustment processing portion adjusts an image forming condition based on the detection result after correction by the correction processing portion.