Sheet Pre-Pressing to Protect Image Carrier Surface
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Solution Overview
Problem
The surface damage of an image carrier in image forming apparatuses due to pressure contact with recording media containing hard additives can compromise toner adhesion detection, leading to inaccurate image density.
Innovation Solution
Incorporating a pressure applying unit with a first roller of metal material and a second roller of rubber material, which press the sheet against the image carrier at a higher pressure than the secondary transfer roller, to prevent surface damage and ensure accurate toner detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the recording medium comes into pressure contact with the image carrier during transfer, then the transfer efficiency is improved, but the surface of the image carrier is minutely damaged by hard additives in the recording medium
Solution Approach 1:
The patent applies preliminary action by pressing the sheet with the pressure applying unit before the transfer process. This pre-pressing embeds hard additives into the sheet in advance, so that during subsequent transfer contact with the image carrier, the additives do not damage the image carrier surface, thus resolving the contradiction between maintaining transfer efficiency and protecting surface integrity.
2Productivity
If the surface of the image carrier is damaged by hard additives, then the transfer process continues, but accurate detection of toner quantity is compromised
Solution Approach 1:
The pressure applying unit performs preliminary pressing to embed hard additives before transfer, preventing surface damage that would otherwise compromise toner quantity detection accuracy. This maintains both continuous operation and measurement precision.
3Device complexity
If no pre-pressing is applied to the sheet, then the device complexity is reduced, but the image carrier surface is damaged leading to inaccurate toner detection
Solution Approach 1:
The patent introduces a pressure applying unit that performs preliminary pressing of the sheet before transfer. This simple structural addition embeds hard additives in advance, preventing image carrier surface damage and maintaining toner detection accuracy without significantly increasing device complexity.
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 configuration allows for accurate detection of toner quantity on the image carrier, maintaining desired image density by preventing additive-induced damage and ensuring consistent toner adhesion.
Implementation Method 1
presses a surface of the sheet at a first pressure which is higher than a second pressure at which the secondary transfer roller presses the sheet against the intermediate transfer belt
Data Source
AI summary
An image forming apparatus includes an intermediate transfer belt, an image forming unit, a transfer unit, a roller configured to transport the sheet to the transfer unit, a light emitting unit configured to irradiate a portion of the outer peripheral surface of the intermediate transfer belt along a width direction of the intermediate transfer belt, a light reception unit configured to detect a quantity of light reflected from the portion of the outer peripheral surface of the intermediate transfer belt, and a pressure applying unit arranged between the roller and the transfer unit in a sheet conveying direction, and configured to press a portion of the sheet in a width direction of the sheet that overlaps with the portion of the outer surface of the intermediate transfer belt.