Roller Speed Adjustment for Sheet Conveyance Control
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Solution Overview
Problem
In image forming apparatuses with multiple roller pairs, the uneven rotational speeds of rollers in different pairs lead to an excess portion of sheet medium between the pairs, causing it to stick or bend, which can result in image formation quality issues.
Innovation Solution
The image forming apparatus includes a controller that adjusts the rotational speeds of the rollers in an upstream and downstream roller pair to maintain an appropriate sheet medium conveyance, performing specific image forming processes to manage the sheet medium feed and prevent excess accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the upstream roller pair rotates faster than the downstream roller pair to increase feed amount, then the sheet medium is fed more efficiently, but an excess portion of sheet medium accumulates between the roller pairs causing sticking and bending
Solution Approach 1:
The patent implements dynamic adjustment of roller rotational speeds based on real-time detection of sheet medium conveyance state. The controller modifies rotation speeds during operation to maintain appropriate sheet amount between roller pairs, resolving the contradiction between feed efficiency and conveyance precision through adaptive control rather than fixed speed ratios
Solution Approach 2:
The patent employs a feedback mechanism where the controller detects the conveyance state of the sheet medium and adjusts the rotational speeds of roller pairs accordingly. This closed-loop control ensures that the sheet medium is fed efficiently while preventing excess accumulation that would cause sticking or bending, by continuously monitoring and adjusting the system parameters
2Ease of operation
If the rotational speeds of rollers in different pairs are made unequal to achieve differential feeding, then feed control is improved, but sheet medium accumulates in excess between roller pairs
Solution Approach 1:
The patent changes the operational parameters (rotational speeds) of the roller pairs dynamically based on the detected sheet medium state. By adjusting rotation speeds within an appropriate range rather than maintaining fixed unequal speeds, the system achieves both differential feeding control and stable sheet medium amount between roller pairs
Solution Approach 2:
The system transitions from static unequal rotational speeds to dynamic speed adjustment. The controller modifies the rotation speeds of roller pairs in real-time based on sheet conveyance detection, enabling both feed control capability and stable sheet amount to be maintained simultaneously through adaptive parameter changes
Data Source
AI summary
An image forming apparatus includes a controller that performs one or more times a first image forming process including performing image formation on a sheet medium, and conveying the sheet medium in a conveyance direction by rotating a first roller by a first number of rotations and rotating a second roller disposed downstream of the first roller in the conveyance direction by a second number of rotations smaller than the first number of rotations. When a count of times the first image forming process has been performed becomes a particular number of times, the controller performs a second image forming process including performing image formation on the sheet medium, and conveying the sheet medium by rotating the first roller by a third number of rotations smaller than the first number of rotations and rotating the second roller by the second number of rotations.