Transfer Voltage Control for Toner-Dependent Image Transfer
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining high-quality print output under high-temperature/high-humidity conditions, particularly in suppressing patch voids in low print-ratio images and toner inversion in high print-ratio images due to improper transfer current distribution.
Innovation Solution
An image forming apparatus with a controller that adjusts the transfer voltage based on toner amount information, applying a smaller absolute value of transfer voltage when the toner amount increases, and using constant-voltage control to ensure consistent transfer quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the transfer current is increased to suppress improper transfer in high print-ratio images, then the transfer quality of high print-ratio images is improved, but patch voids occur in low print-ratio images due to excessive current flowing through white portions
Solution Approach 1:
The patent applies dynamic control by switching between constant-current control and constant-voltage control modes based on the print ratio. For high print-ratio images, constant-current control is used to ensure sufficient transfer current. For low print-ratio images, constant-voltage control is used to prevent excessive current. This dynamic switching resolves the contradiction by adapting the control mode to the specific image characteristics.
Solution Approach 2:
The patent changes the control parameter from constant current to constant voltage based on the print ratio. By switching the control mode parameter, the system can optimize transfer current for high print-ratio images while preventing patch voids in low print-ratio images, thus resolving the technical contradiction.
2Manufacturing precision
If the transfer voltage is set to provide sufficient transfer current for isolated patch patterns, then transfer of low print-ratio images is improved, but excessive current causes toner inversion in high print-ratio images
Solution Approach 1:
The patent implements dynamic control mode switching based on print ratio detection. For low print-ratio images with isolated patches, constant-voltage control provides sufficient current. For high print-ratio images, constant-current control prevents excessive current. This dynamic adaptation resolves the contradiction between transfer uniformity and toner inversion prevention.
Solution Approach 2:
The system uses feedback by detecting the print ratio and adjusting the control mode accordingly. The controller determines whether to apply constant-current or constant-voltage control based on the measured print ratio, creating a closed-loop system that prevents both insufficient and excessive current conditions.
3Stability of the object's composition
If constant-voltage control is applied to maintain consistent transfer voltage, then transfer stability is improved, but current distribution becomes uneven in high-temperature/high-humidity environments
Solution Approach 1:
The patent applies dynamic control mode switching based on environmental conditions and print ratio. In high-temperature/high-humidity environments with low print-ratio images, constant-voltage control maintains stability. For high print-ratio images in the same environment, constant-current control ensures uniform current distribution. This resolves the contradiction by adapting to both environmental and image-specific conditions.
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
The solution effectively suppresses patch voids in low print-ratio images and prevents toner inversion in high print-ratio images, ensuring high-quality print output even in challenging environmental conditions.
Implementation Method 1
The transfer of the toner image from the image bearing member onto the recording material is carried out by applying a transfer voltage to the transfer member
Implementation Method 2
a transfer current is liable to selectively flow through a portion where toner which has a low resistance (low electric resistance value) does not exist
Data Source
AI summary
An image forming apparatus includes an image bearing member, a transfer member, an acquiring portion, an applying portion, and a controller. When a transfer voltage is subjected to constant-voltage control so that the transfer voltage applied to the transfer member by the applying portion is substantially constant, in a case that the transfer voltage, when a toner amount used for a toner image is a first toner amount, is a first voltage, the controller controls the applying portion so that the transfer voltage is a second voltage lower in absolute value than the first voltage in a case that the toner amount is a second toner amount greater than the first toner amount. The acquiring portion acquires toner amount information on the toner amount for each toner image transferred onto a single recording material.