Developer Carrying Member Rotation Control for Image Density Stability
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Solution Overview
Problem
In image forming apparatuses, the fixing of developer substances on the regulating member leads to poor image density and vertical stripes due to blocked developer flow, especially during high print ratio operations.
Innovation Solution
The image forming apparatus includes a controller that adjusts the rotation amount of the developer carrying member based on count values from divided regions, performing a developing rotation operation during non-image forming periods to maintain developer flow stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the regulating member is used to form a uniform developer layer, then the developer layer thickness stability is improved, but the developer substance gets fixed on the regulating member blocking developer flow
Solution Approach 1:
The patent applies preliminary action by performing a developing rotation operation during non-image forming periods. This rotation operation is executed in advance to prevent developer substance from being fixed on the regulating member before it can block the developer flow during actual image forming operations.
Solution Approach 2:
The patent implements periodic action by alternating between image forming operations and developing rotation operations. The developing rotation operation is periodically executed during non-image forming periods, creating a cyclic pattern that maintains developer flow stability while preventing substance fixation on the regulating member.
2Productivity
If high print ratio images are formed continuously, then productivity is improved, but developer substance fixation occurs more frequently causing image defects
Solution Approach 1:
The patent uses periodic action by inserting developing rotation operations between continuous image forming operations. This creates a rhythm where high-productivity image forming is alternated with maintenance rotations, ensuring that developer flow remains stable and image quality remains consistent even during extended printing sessions.
Solution Approach 2:
The patent maintains continuity of useful action by utilizing non-image forming periods for developing rotation operations. This ensures that the developer carrying member continues to rotate and maintain proper developer distribution even when not actively forming images, preventing substance fixation without interrupting overall productivity.
3Object-generated harmful factors
If the developer carrying member rotation is increased to prevent substance fixation, then developer flow stability is improved, but the layer thickness uniformity may be affected
Solution Approach 1:
The patent applies preliminary action by performing the developing rotation operation during non-image forming periods. This timing ensures that the rotation is completed in advance, allowing the developer layer to stabilize before the next image forming operation begins, thus maintaining both substance fixation prevention and layer thickness uniformity.
Solution Approach 2:
The patent implements self-service by allowing the developing rotation operation to naturally redistribute the developer substance on the developer carrying member. This self-regulating mechanism maintains proper developer flow and layer uniformity without requiring external intervention or complex control systems.
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 solution effectively suppresses image defects like poor image density and vertical stripes by maintaining a stable developer layer thickness, even during high print ratio operations.
Implementation Method 1
a surface of an image bearing member is electrically charged uniformly by a charging means
Implementation Method 2
the charged surface of the image bearing member is exposed to light by an exposure means on the basis of an image signal, so that an electrostatic latent image is formed
Implementation Method 3
a developing device including a rotatable developer carrying member for conveying the developer to an opposing portion to the image bearing member while carrying the developer and a regulating member for regulating a developer amount of a developer layer on the developer carrying member
Data Source
AI summary
An image forming apparatus includes an image bearing member, a charging member, an exposure unit, a developing unit including a developer carrying member and a regulating member, a transfer member, a counting portion, a driving portion, and a controller. The controller carries out control so as to perform an image forming operation capable of forming a developer image, on the image bearing member, to be transferred onto a recording material and a non-image forming operation in which the developer image to be transferred onto the recording material is not formed on the image bearing member. Depending on each of count values in a plurality of regions acquired by the counting portion in a predetermined period, the controller controls the driving portion so as to change a rotation amount of the developer carrying member in a developing rotation operation for rotating the developer carrying member during the non-image forming operation.