Developing Roller Switching for Monochrome Toner Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In image forming apparatuses, non-black color toners are inadvertently transferred onto the sheet during monochrome image formation when yellow, magenta, and cyan photosensitive members are kept apart from their corresponding developing rollers, leading to unwanted color contamination on monochrome images.
Innovation Solution
An image forming apparatus with a switching mechanism that shifts developing rollers between all-color contact and black contact states, allowing non-black color toners to be recovered and transferred back onto the photosensitive members before switching to monochrome mode, preventing their transfer onto the sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-black color photosensitive members are kept apart from corresponding developing rollers during monochrome image formation, then monochrome image formation is enabled, but non-black color toners are inadvertently transferred onto the sheet causing color contamination
Solution Approach 1:
The recovery rollers are operated to recover non-black color toners from the photosensitive members before the monochrome image formation process begins. This preliminary recovery action prevents the toners from being inadvertently transferred onto the sheet during subsequent monochrome printing, thus eliminating color contamination while maintaining monochrome image formation capability
Solution Approach 2:
The recovery rollers serve as intermediary components between the photosensitive members and the sheet. By positioning and operating these recovery rollers, the system mediates the potential harmful transfer of non-black color toners, intercepting them before they can contaminate the monochrome image on the sheet
2Reliability
If developing rollers are spaced from photosensitive members, then toner recovery is improved, but released toner is transferred onto the sheet or intermediate transfer belt
Solution Approach 1:
The recovery rollers act as intermediary components that intercept toner released from the photosensitive members. By positioning these recovery rollers in close proximity to the photosensitive members, the system captures released toner before it can be transferred onto the sheet or intermediate transfer belt, thus converting a harmful effect into a controlled recovery process
Solution Approach 2:
The invention extracts the toner recovery function from the developing roller system and implements it through separate recovery rollers. This extraction allows the developing rollers to be spaced from the photosensitive members for reliable toner recovery, while the recovery rollers simultaneously prevent released toner from contaminating the sheet
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
Effectively prevents non-black color toners from being transferred onto the sheet during monochrome image formation, ensuring clean monochrome images by controlling the contact states of developing rollers and using recovery members to manage toner transfer.
Implementation Method 1
The toner remaining on the photosensitive member is transferred onto the recovery roller from the photosensitive member by static electricity when being brought into opposed relation to the recovery roller
Implementation Method 2
The toner transferred onto the recovery roller is electrostatically adsorbed on the recovery roller to be accumulated on the recovery roller
Implementation Method 3
the toner released from the recovery roller onto the photosensitive member is transferred onto the developing roller when being brought into opposed relation to the developing roller with the developing roller kept in contact with the photosensitive member
Data Source
AI summary
An image forming apparatus is provided which includes a switching mechanism which selectively shifts developing rollers among an all-color non-contact state in which all photosensitive members are kept apart from the corresponding developing rollers, a black contact state in which only the photosensitive member for black is kept in contact with the corresponding developing roller, and an all-color contact state in which all the photosensitive members are kept in contact with the corresponding developing rollers, and a control section which, when an operation mode of the apparatus is shifted from a color mode to a monochrome mode, causes the switching mechanism to shift the developing rollers from the all-color contact state to the all-color non-contact state to perform a transferring process to once transfer developing agents from recovery members onto the corresponding photosensitive members and further transfer the developing agents from the photosensitive members onto a transfer belt.