Intermediate Transfer Belt Current Supply for Compact Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses require multiple voltage sources for first transfer, leading to increased size and cost, and may experience premature wear of photosensitive drums due to uneven pressure, with residual toner charging affecting transfer unit performance.
Innovation Solution
The apparatus supplies current in the rotational direction of the intermediate transfer belt, eliminating the need for multiple voltage sources and using a single power source for both first and second transfers, while maintaining the intermediate transfer belt's potential for efficient toner recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple voltage sources are used for first transfer in each image forming part, then appropriate first transfer voltage can be set for each part, but the size and cost of the apparatus increases
Solution Approach 1:
The patent combines multiple first transfer voltage sources into a single shared voltage source that serves all image forming parts. The intermediate transfer belt acts as a common electrical pathway, allowing one voltage source to provide the necessary first transfer voltage to multiple photosensitive drums simultaneously, thereby reducing apparatus complexity while maintaining transfer performance
Solution Approach 2:
The intermediate transfer belt serves multiple functions: it acts as both the transfer medium for toner images and as an electrical conductor that distributes voltage from a single source to multiple first transfer portions. This multi-functionality eliminates the need for separate voltage sources for each image forming part
2Power
If first transfer rollers press photosensitive drums at predetermined pressure before image formation, then transfer voltage can be supplied, but photosensitive drums wear earlier than expected
Solution Approach 1:
The patent applies voltage to the intermediate transfer belt before the actual image transfer process begins. This preliminary voltage application establishes the electrical field necessary for toner transfer without requiring mechanical pressure on the photosensitive drums during non-operational periods, thereby reducing wear while ensuring power is available when needed
Solution Approach 2:
The patent replaces the mechanical pressure system with an electrical field-based system. Instead of relying on first transfer rollers to press photosensitive drums mechanically to supply transfer voltage, the system uses voltage applied to the intermediate transfer belt to create an electrical field that enables toner transfer, eliminating the need for continuous mechanical contact and pressure
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 reduces the size and cost of the apparatus, extends the life of photosensitive drums, and maintains optimal transfer performance by ensuring the intermediate transfer belt's potential is maintained, thereby enhancing overall efficiency and reliability.
Implementation Method 1
The toner images developed onto the photosensitive drums of the image forming parts are first-transferred to the intermediate transfer belt by first transfer rollers... The toner images that have been first-transferred to the intermediate transfer belt are then second-transferred to a transfer medium by a second transfer unit
Implementation Method 2
a residual toner remaining on an intermediate transfer belt is charged by a charging member and then transferred to an image forming part
Data Source
AI summary
The present invention relates to an image forming apparatus that forms an image by consecutively superposing toner images that have been formed on a plurality of photosensitive drums, on an intermediate transfer member or a transfer medium. The image forming apparatus is made compact and operates at a low cost. Since a current supply member supplies a current in a rotational direction of an intermediate transfer belt, multiple first transfer portions do not need corresponding voltage sources. Even in the case where a charging member supplies a current, the potential of the intermediate transfer belt is maintained at a predetermined potential by a constant-voltage element connected to support rollers.