Pre-Transfer Grounding Control for Stable Toner Transfer on Mixed Paper
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face challenges in stabilizing the transfer of toner images onto metalized paper due to its high conductivity and low impedance, leading to unstable current flow, and on thin paper due to warping and loss of contact with the contact member, resulting in inconsistent transfer properties.
Innovation Solution
The apparatus includes a pre-transfer contact unit with a contact member and a switching unit that controls the grounding state of the contact member based on the paper type and basis weight, ensuring stable current flow by grounding the contact member for metalized paper and avoiding grounding for thin paper, using a columnar metal member or metallic string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact member is provided to ground the recording material for stable current flow, then stable transfer is achieved on metalized paper, but thin paper warps and breaks contact causing unstable transfer
Solution Approach 1:
The contact member is made movable along the conveyance direction, allowing it to dynamically adjust its position. For metalized paper, it contacts the paper to provide grounding and stabilize current flow. For thin paper that warps, it follows the paper's contour or disengages, maintaining contact without causing warping or breaking contact, thus adapting to different paper types while ensuring reliable transfer
Solution Approach 2:
The contact member's position parameter is changed along the conveyance direction based on the paper type. By adjusting where the contact member interacts with the recording material during conveyance, the system optimizes grounding for metalized paper while avoiding excessive contact that would warp thin paper, thereby resolving the contradiction between transfer stability and adaptability
2Reliability
If constant-voltage control is used to maintain constant bias voltage, then transfer is stable on normal paper, but current becomes unstable on metalized paper due to its high conductivity
Solution Approach 1:
The contact member acts as an intermediary element between the recording material and ground. For metalized paper, it provides an additional current path through grounding, stabilizing the current flow by preventing excessive current fluctuations that occur with constant-voltage control alone, thereby enabling stable transfer on high-conductivity materials
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 maintains stable transfer of toner images irrespective of paper type and basis weight, preventing fluctuations in current flow and ensuring consistent image transfer quality.
Implementation Method 1
a contact member for grounding the recording material to be conveyed to the transfer portion
Data Source
AI summary
An image forming apparatus includes an image bearing member, an image former configured to form an image on the image bearing member, a transfer portion configured to transfer the image formed on the image bearing member onto a recording material, a conveyor configured to convey the recording material to the transfer portion, a contact portion provided upstream of the transfer portion in a conveyance direction of the recording material and having a contact member for grounding the recording material to be conveyed to the transfer portion, and at least one processor configured to control, in a case where the recording material is of a first paper type, the contact portion so that the recording material is grounded by the contact member.