Photosensitive Drum Scratch Prevention During Jam Clearing
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Solution Overview
Problem
Image forming apparatuses face damage to photosensitive drums and conveyance belts due to jamming, leading to scratches and image quality deterioration, as existing solutions either fail to completely prevent rubbing or result in toner contamination.
Innovation Solution
An image forming apparatus with a detection system that forms a toner adhesion region on the photosensitive drum and synchronizes the cessation of drum and belt rotation, applying a voltage of the same polarity as the toner to the transfer roller to prevent toner movement and maintain a toner layer at the contact position, thereby reducing friction and preventing scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the transfer unit is separated from the photosensitive drum to clear jamming, then the jammed sheet can be removed, but the photosensitive drum and conveyance belt rub against each other causing scratches
Solution Approach 1:
The system performs preliminary action by forming a toner adhesion region on the photosensitive drum before the transfer unit is separated for jam clearing. This toner layer is prepared in advance to protect the contact surface between the drum and conveyance belt during the subsequent separation and rubbing operation, preventing scratches while enabling easy jam removal
Solution Approach 2:
The toner layer acts as an intermediary substance between the photosensitive drum and the conveyance belt. When the transfer unit is separated for jam clearing, this intermediary toner layer absorbs the rubbing contact, preventing direct friction between the drum surface and belt, thus avoiding scratches while still allowing the mechanical separation to occur
2Object-affected harmful factors
If a voltage of the same polarity as toner is applied to the transfer roller, then the toner layer is maintained at the contact position preventing scratches, but toner may move toward the conveyance belt
Solution Approach 1:
The system changes the voltage parameter of the transfer roller to have the same polarity as the toner charge. This parameter change creates an electrostatic repulsion that prevents the toner layer from moving toward the conveyance belt, while simultaneously maintaining the toner adhesion region at the contact position to protect against scratches during jam clearing operations
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 scratches on the photosensitive drum and conveyance belt during jam clearing, maintains image quality, and avoids toner contamination, ensuring safe user operation by maintaining a toner layer at the contact position between the drum and belt.
Implementation Method 1
an electrification unit 4 for evenly electrifying a surface of the photosensitive drum
Implementation Method 2
an exposure unit 5 for writing an electrostatic latent image onto the surface of the photosensitive drum
Implementation Method 3
a development unit for adhering toner to the surface of the photosensitive drum to form a toner image according to the electrostatic latent image
Implementation Method 4
an electric field is given to a lower portion of the photosensitive drum 3 by a transfer roller 17 to which a predetermined transfer voltage is applied, so that the toner image on the photosensitive drum 3 is transferred onto the sheet 7
Implementation Method 5
The conveyance belt 8, the conveyance rollers 15 and 16 and the transfer roller 17 configure a transfer unit R for transferring a toner image onto the sheet 7
Data Source
AI summary
Upon occurrence of jamming in an apparatus, an electrification unit 4 ceases electrification of a surface of a photosensitive drum 3 and, simultaneously, an exposure unit 5 starts to expose the entire surface in a width direction to light. Further, a development unit 6 forms a toner adhesion region T on the photosensitive drum 3 and, also, stops a drum motor and a belt motor in such a manner that the toner adhesion region T stops at a transfer nip section N. Thus, it is possible to alleviate a rub between the photosensitive drum 3 and a conveyance belt 8 at the time when jamming is cleared, and to suppress generation of scratches on the photosensitive drum 3 and a surface of the conveyance belt 8.