Sheet Feed Device Inclination Adjustment for Multi-Cassette Reliability
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Solution Overview
Problem
Existing sheet feed devices in image recording apparatuses face challenges in reliably feeding sheets of different sizes and types from multiple cassettes, as the inclination angle of the sheet feed arm is insufficient for smaller sheets, leading to inadequate force for proper feeding.
Innovation Solution
A sheet feed device with a second cassette that moves above the first cassette, featuring a sheet feed roller that contacts sheets at an inclined surface to increase the force applied, ensuring stable feeding of sheets of varying sizes and types by adjusting the inclination angle and using a cam follower mechanism for precise movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet feed arm is designed with a fixed inclination angle for standard sheets, then it can properly feed standard-sized sheets, but it cannot apply sufficient force to feed smaller sheets reliably
Solution Approach 1:
The sheet feed arm is designed to be movable rather than fixed, allowing its inclination angle to be dynamically adjusted. The arm can pivot between a first inclination angle for standard sheets and a second inclination angle for smaller sheets, enabling the system to adapt to different sheet sizes while maintaining reliable feeding for each type.
Solution Approach 2:
The inclination angle parameter of the sheet feed arm is changed based on the sheet size being fed. By adjusting this geometric parameter between two specific angles, the system optimizes the feeding force application for different sheet dimensions, resolving the contradiction between reliability for standard sheets and adaptability to smaller sheets.
2Device complexity
If a single sheet feed mechanism is used for both cassettes, then the device structure remains simple, but it cannot simultaneously accommodate and feed different sheet types from both cassettes
Solution Approach 1:
A single sheet feed arm is designed to perform multiple functions by serving both the first cassette (standard sheets) and the second cassette (smaller sheets). The arm can be positioned to feed from either cassette depending on its inclination angle, providing universal functionality without requiring separate feed mechanisms for each cassette type.
Solution Approach 2:
The movable sheet feed arm dynamically repositions between two operational states: one for feeding standard sheets from the first cassette and another for feeding smaller sheets from the second cassette. This dynamic positioning allows one mechanism to handle multiple sheet types while maintaining structural simplicity.
3Productivity
If the sheet feed roller applies strong force to feed sheets quickly, then productivity increases, but smaller sheets may be damaged or fed incorrectly due to excessive force
Solution Approach 1:
The inclination angle parameter of the sheet feed arm is adjusted based on sheet size: a first inclination angle for standard sheets that allows stronger feeding force, and a second inclination angle for smaller sheets that reduces the effective feeding force. This parameter change ensures appropriate force application for each sheet type, maintaining both productivity and reliability.
Solution Approach 2:
The sheet feed arm provides different local conditions (inclination angles) for different sheet types. By creating a specific geometric configuration tailored to each sheet size, the system optimizes the force application locally, preventing damage to smaller sheets while maintaining efficient feeding of standard sheets.
Data Source
AI summary
A sheet feed device includes a first sheet cassette including an accommodating portion configured to accommodate a first plurality of sheets, and a second sheet cassette disposed on the first sheet cassette and including a holding portion configured to hold a second plurality of sheets, in which one or more characteristics of the first plurality of sheets is different than one or more characteristics of the second plurality of sheets. The sheet feed device also includes a sheet feeder including a sheet feed roller, and the sheet feed device is configured to selectively feed the first plurality of sheets and the second plurality of sheets in a sheet feed direction toward a recording unit. Moreover, the sheet feed device includes a sheet separator configured to separate, one by one, the sheets fed by the sheet feeder. Specifically, the second sheet cassette is configured to move above the accommodating portion of the first sheet cassette and with respect to the sheet feeder, and the sheet feed roller is configured to contact the second plurality of sheets on the holding portion that is inclined so as to increase in height in a direction toward the sheet separator.