Transfer Member Cleaning Control for Envelope Toner Contamination
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Solution Overview
Problem
Image forming apparatuses face contamination issues with toner on transfer members due to protruded toner images on envelope flaps, leading to back contamination of subsequent recording materials.
Innovation Solution
An image forming apparatus with a controller that alternates application of cleaning voltages of the same and opposite polarity to the toner charge on the transfer member during continuous printing when an envelope is used, ensuring effective cleaning before the next recording material is transferred.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an image is formed on the flap of an envelope, then the toner image can be transferred onto the envelope surface, but the protruded toner image deposits on the transfer member causing contamination
Solution Approach 1:
The patent applies a preliminary cleaning voltage of opposite polarity to the transfer member before the next recording material reaches the transfer portion. This preliminary action removes protruded toner from the transfer member surface that resulted from the previous envelope flap imaging, preventing contamination of subsequent recording materials.
Solution Approach 2:
The patent implements periodic cleaning cycles during continuous printing operations. When an envelope is detected as the recording material, the system periodically applies cleaning voltage of opposite polarity at specific intervals (after the envelope passes through and before the next material arrives) to remove accumulated toner from the transfer member surface.
2Object-affected harmful factors
If cleaning voltage of opposite polarity is applied to remove toner from transfer member, then transfer member contamination is reduced, but additional voltage application increases system complexity
Solution Approach 1:
The transfer member cleaning function is integrated into the existing voltage application system. The same applying portion that applies transfer voltage during normal operation also applies cleaning voltage of opposite polarity during cleaning cycles, allowing the system to clean itself without requiring separate cleaning hardware.
Solution Approach 2:
The voltage applying portion is designed to perform multiple functions: it applies transfer voltage during normal imaging operations and switches to applying cleaning voltage of opposite polarity during cleaning cycles. This multi-functionality eliminates the need for separate cleaning voltage sources or additional cleaning hardware.
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
Prevents contamination of transfer members by efficiently removing toner from envelope flaps, thereby reducing back contamination on subsequent recording materials.
Implementation Method 1
a voltage of an opposite polarity to a voltage during the transfer is applied to the transfer member, so that an electric field in a direction opposite to an electric field during the transfer is formed between the transfer member and the image bearing member. By this, the toner deposited on the transfer member is moved to the image bearing member
Implementation Method 2
a transfer voltage of an opposite polarity to a normal charge polarity of toner is applied, and the toner is electrostatically attracted to the recording material passing through a transfer portion
Data Source
AI summary
An image forming apparatus includes an image bearing member; a toner image forming portion, a transfer member, a voltage applying portion, an acquiring portion, and a controller. In continuous printing in which toner images are continuously transferred onto a first recording material and a second recording material, in a case that the first recording material is an envelope on the basis of recording material information, the controller carries out control so that a transfer member cleaning operation, in which a first cleaning voltage of the same polarity as a normal charge polarity of toner and a second cleaning voltage of an opposite polarity to the normal charge polarity of the toner are alternately applied by the voltage applying portion, is executed after the first recording material passes through the transfer portion and before the second recording material reaches the transfer portion.