Common Driving Source Image Forming Apparatus Contact Separation Control
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Solution Overview
Problem
Conventional image forming apparatuses using contact development type electrophotographic processes face issues such as increased wear and tear of photosensitive drums and developing rollers, leading to image defects like white and fog stripe images due to load fluctuations and prolonged contact times, which complicate the system and increase costs.
Innovation Solution
An image forming apparatus with a common driving source for multiple image bearing members and developing units, featuring a contact-and-separation mechanism that allows for controlled contact and separation of developing members with image bearing members, reducing contact opportunities and minimizing load fluctuations during image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common driving source is used for multiple image bearing members, then device complexity is reduced and cost is lowered, but load fluctuations occur during spacing operations affecting image quality
Solution Approach 1:
The developing member is spaced from the image bearing member before the spacing operation is actually needed. The control unit outputs a spacing signal at timing that ensures the developing member is already separated when the spacing operation occurs, preventing load fluctuations from affecting the image bearing member rotation
Solution Approach 2:
The control unit independently controls the spacing operation of each developing member corresponding to different image bearing members. This allows selective spacing of only those developing members whose image bearing members are undergoing spacing operations, while other developing members remain in contact to maintain stable rotation of their associated image bearing members
2Productivity
If developing members are continuously contacted with image bearing members, then image formation efficiency is improved, but wear and deterioration of components increases
Solution Approach 1:
The developing member periodically contacts and separates from the image bearing member based on image formation needs. During spacing operations, the developing member is separated from the image bearing member, reducing contact time and wear. The contact-and-separation unit enables this periodic contact pattern to balance productivity with component longevity
Solution Approach 2:
The contact state between the developing member and image bearing member is dynamically adjusted based on operational requirements. The contact-and-separation unit allows the system to transition between contact and separation states, optimizing both image formation efficiency and reducing mechanical wear through controlled intermittent contact
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 simplifies the apparatus structure, reduces costs, and minimizes image defects by shortening contact times between photosensitive drums and developing rollers, thereby extending their lifespan and improving image quality.
Implementation Method 1
a charging unit for applying a charge to a surface of the photosensitive drum
Implementation Method 2
an exposing unit for forming a latent image on the photosensitive drum
Implementation Method 3
a developing unit for developing the latent image on the photosensitive drum in a contact state between the photosensitive drum and a developing roller
Data Source
AI summary
An image forming apparatus includes image bearing members, a latent image forming portion, developing units each including a developing member, a movable member, a common driving source, a contact-and-separation unit, and a control unit. The image forming apparatus is capable of forming the images in an operation in an image forming mode. After end of the latent image formation on one of the image bearing members on which latent image formation is finally started and before end of transfer of an associated image from the one image bearing member, the control unit outputs a spacing signal for spacing associated developing members from the other image bearing members, during the image formation in the operation in the mode.