Transfer Guide Protrusion for Image Alignment in Printers
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Solution Overview
Problem
Image failures due to spring back occur when the trailing edge of a transfer medium hits the image carrier, especially with rigid papers, leading to toner scattering and misalignment, which existing methods fail to fully address without using flexible shielding plates or adjusting transfer current values.
Innovation Solution
An image forming apparatus with a pair of opposing transfer guide members, where the front edge of one guide member is protruded and angled relative to the trailing edge of the transfer medium, allowing for controlled guidance and reduced impact shock during transfer, without using flexible films or approaching the transfer guide member to the image carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible shielding plate is bonded to the transfer guide member, then spring back of the trailing edge is prevented, but thin paper cannot be sufficiently conveyed and uneven conveyance occurs
Solution Approach 1:
The transfer guide member is divided into multiple sections: a first transfer guide member and a second transfer guide member positioned at different locations. This segmentation allows each guide member to independently manage different aspects of paper conveyance, preventing spring back in rigid papers while allowing thin papers to pass through without obstruction.
Solution Approach 2:
The first transfer guide member is positioned closer to the image carrier to specifically address spring back prevention, while the second transfer guide member is positioned farther away to handle thin paper conveyance. This local differentiation in positioning ensures that each area of the guide system has the appropriate characteristics for its specific function.
2Reliability
If the transfer guide member is approached close to the image carrier, then spring back is reduced, but toner contamination occurs
Solution Approach 1:
By segmenting the guide system into two members at different positions, the first guide member can be placed close enough to control spring back without requiring the second guide member (which handles thin papers) to be in the same position, thus avoiding toner contamination while still preventing spring back for rigid papers.
Solution Approach 2:
The first transfer guide member acts as an intermediary element between the paper and the image carrier, providing the necessary guidance and spring back prevention without requiring direct contact between the paper and the image carrier, thereby preventing toner contamination.
3Manufacturing precision
If transfer current value is adjusted to eliminate toner scattering, then image misalignment is reduced, but image failure occurs in solid or half-tone images
Solution Approach 1:
The transfer guide members are positioned to preliminarily control the paper path and prevent spring back before the transfer process occurs. This preliminary alignment control eliminates the need to adjust transfer current values to compensate for misalignment, thereby avoiding image failure in solid or half-tone areas while maintaining proper image alignment.
Data Source
AI summary
An image forming apparatus having: an image forming section to form a toner image on an image carrier; a transfer section to transfer onto a transfer medium the toner image formed on the image carrier; and a pair of opposing transfer guide members to guide the transfer medium into the transfer section, wherein a front edge of one transfer guide member, arranged on a side of the image carrier out of the pair of the transfer guide members, is disposed separately from the other transfer guide member, and one side portion of the front edge of the transfer guide member is more protruded than the other side portion into a conveying direction of the transfer medium.