Sheet Conveyance Roller Tilt Restriction for Image Forming
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Solution Overview
Problem
Conventional medium conveying devices experience sheet misalignment and jamming due to spur rollers tilting, leading to improper sheet discharge and potential image defects.
Innovation Solution
A medium conveying apparatus with driving and driven rollers, supported by swinging arms and restriction parts that prevent tilting, ensuring stable sheet conveyance and reduced impact on the sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If spur rollers are used to convey sheets, then conveyance function is achieved, but rollers tilt due to reaction forces causing sheet misalignment and jamming
Solution Approach 1:
A tilting restriction mechanism is introduced as an intermediary component between the spur rollers and the sheet conveyance system. This mechanism includes restriction parts that contact the rollers to prevent tilting, while biasing members apply necessary forces to maintain proper contact pressure. This intermediary structure resolves the contradiction by allowing the rollers to perform their conveyance function while preventing the tilting that causes misalignment and jamming.
2Productivity
If rollers are made rotatable to enable conveyance, then conveyance capability is improved, but roller tilt causes oblique sheet movement and discharge failures
Solution Approach 1:
The system employs dynamic elements including biasing members that can elastically deform to accommodate roller movement while maintaining restriction on tilting. The biasing members apply variable forces depending on the operational state, allowing the rollers to rotate for conveyance while being dynamically constrained against excessive tilting that would cause discharge misalignment.
Solution Approach 2:
The tilting restriction mechanism acts as an intermediary between the rotational motion of rollers and the sheet discharge process. By introducing this intermediate constraint system, the rollers can maintain their rotational conveyance function while the restriction parts prevent the tilting that would otherwise cause oblique sheet movement and discharge failures.
3Strength
If friction force is increased on discharge roller surface, then sheet grip is improved, but reaction forces cause greater roller tilting
Solution Approach 1:
The tilting restriction mechanism serves as an intermediary that decouples the friction force generation from the roller tilting. The restriction parts contact the rollers to prevent tilting while the biasing members maintain the necessary friction contact. This allows high friction force to be applied to the discharge roller surface for improved sheet grip without allowing the roller to tilt in response to reaction forces.
Solution Approach 2:
The biasing members act as counterweight elements that apply opposing forces to balance the reaction forces causing roller tilting. By introducing these counterbalancing forces through the biasing members, the system can maintain high friction force for sheet grip while the counterweight mechanism prevents the roller from tilting under the action of reaction forces.
Data Source
AI summary
A medium conveying apparatus includes a driving roller, a plurality of driven rollers, a support part, a plurality of upstream restriction parts and a plurality of downstream restriction parts. The support part supports the driven rollers. The upstream restriction parts are provided in the support part between the adjacent driven rollers. The downstream restriction parts are provided in the support part between the adjacent driven rollers. The upstream restriction parts and the downstream restriction parts are arranged on an upstream side and a downstream side in a conveyance direction of the medium across a rotational center of the driven rollers respectively. When the driven rollers are tilted with respect to the conveyance direction, at least one of the upstream restriction parts and the downstream restriction parts comes into contact with side surfaces of the driven rollers to restrict tilting of the driven rollers.