Image Forming Apparatus Transfer Control via Length Ratio
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Solution Overview
Problem
Existing image forming apparatuses face issues with defective toner image transfer due to inappropriate selection between constant-voltage control and constant-current control, which is often determined solely based on sheet type, leading to inefficiencies in image formation.
Innovation Solution
An image forming apparatus with a controller that switches between constant-voltage control and constant-current control based on a length ratio of the recording medium to the nip part and its basis weight, ensuring optimal transfer scheme selection to prevent defective transfers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If constant-voltage control or constant-current control is selected based solely on sheet type, then the control scheme can be simplified, but defective transfer of toner image occurs
Solution Approach 1:
The patent changes the control parameter selection criteria from sheet type alone to a combination of sheet length ratio (L1/L2) and sheet type. This parameter change enables more accurate matching of control schemes (constant-voltage or constant-current) to actual transfer conditions, resolving the contradiction between simplified control and reliable transfer by introducing a geometric parameter that directly affects transfer characteristics
2Reliability
If the control scheme is dynamically adjusted based on length ratio and sheet type, then toner image transfer quality improves, but the control system becomes more complex
Solution Approach 1:
The patent implements preliminary determination of the control scheme by calculating the length ratio L1/L2 and selecting the appropriate control mode (constant-voltage or constant-current) before the actual image formation process. This preliminary action eliminates the need for complex real-time adjustments during operation, achieving high transfer quality while keeping the control system relatively simple through advance planning
3Productivity
If constant-voltage control is used for short recording media, then transfer efficiency is maintained, but defective transfer occurs for certain sheet types
Solution Approach 1:
The patent introduces dynamic selection between constant-voltage control and constant-current control based on the length ratio L1/L2 and sheet type characteristics. This dynamic approach allows the system to adapt the control mode to match the specific transfer conditions, ensuring both high transfer efficiency and reliable transfer quality across different sheet types and lengths
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 reduces defective toner image transfers by dynamically selecting the appropriate control scheme based on the length ratio and basis weight, enhancing the reliability and quality of the image forming process.
Implementation Method 1
a transfer member configured to nip at a nip part a recording medium that is transported and the circulating member and to transfer the toner image on the circulating member to the recording medium with a voltage being applied to the transfer member
Data Source
AI summary
An image forming apparatus includes a circulating member to be made to circulate while carrying a toner image on a peripheral surface; a transfer member configured to nip at a nip part a recording medium that is transported and the circulating member and to transfer the toner image on the circulating member to the recording medium with a voltage being applied to the transfer member; and a controller configured to control a transfer scheme in accordance with which a voltage is to be applied to the transfer member, the controller being capable of switching the transfer scheme between constant-voltage control and constant-current control, the controller causing an image forming section configured to form an image on the circulating member to start an image forming operation under constant-voltage control selected as the transfer scheme if a length ratio defined as a ratio of a length of the recording medium in an axial direction to a length of the nip part in the axial direction is smaller than a predetermined ratio.