Image Density Stabilization via Sensor Data Conversion
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining stable image quality due to variations in calibration methods, particularly when different sensors are used, leading to inconsistencies in target values and correction amounts.
Innovation Solution
An image forming apparatus is designed with an image processor, image forming unit, transfer unit, fixing unit, conveyance roller, reading unit, detector, and controller to form and read pattern images on both the image bearing member and recording sheet, generating conversion conditions to stabilize image density across different calibration methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If calibration is performed using different methods (reading test image on recording material vs. reading test image on image bearing member), then calibration can be performed in real time during print job, but target value and correction amount vary leading to unstable image density
Solution Approach 1:
The patent introduces a conversion table as an intermediary mechanism that translates reading results from the recording material sensor into equivalent detection results from the image bearing member sensor. This mediator enables the system to use the convenient real-time calibration method (reading on recording material) while maintaining the accuracy standards of the more precise method (reading on image bearing member), thus resolving the contradiction between productivity and manufacturing precision.
2Productivity
If calibration is performed by reading test image on recording material, then productivity is maintained without interruption, but image density stability deteriorates due to sensor variations
Solution Approach 1:
The system implements a feedback mechanism where the reading unit reads the test image on the recording material, the controller converts this reading using the conversion table to simulate what the detector would read, and then uses this converted value to determine appropriate correction amounts. This feedback loop ensures that even though the physical sensor reads from the recording material, the control system responds as if reading from the image bearing member, maintaining image density consistency while enabling continuous operation.
Data Source
AI summary
An image forming apparatus includes an image processor configured to convert image data based on a first conversion condition; an image forming unit configured to form an image on a sheet based on the image data converted by the image processor, the image forming unit having an image bearing member on which the image is to be formed, a transfer unit configured to transfer the image from the image bearing member onto the sheet, and a fixing unit configured to fix the image to the sheet; a conveyance roller configured to convey the sheet having the image fixed thereto; a reading unit configured to read a pattern image on the sheet conveyed by the conveyance roller; and a detector configured to detect a pattern image on the image bearing member.