Sheet Feeding Device Cam Control for Jam Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sheet feeding devices in image forming apparatuses face issues with space efficiency and cost due to the need for larger components to prevent no-feed jams, which occur when the feed roller or separation portion slips, leading to unreliable sheet feeding.
Innovation Solution
A sheet feeding device with a rotatable support member and cam mechanism that controls the sheet feeding portion's position, using a motor to move the sheet feeding portion between standby and feeding positions, and employing detection portions to manage the rotation speed and angle of the cam for reliable sheet feeding, allowing for space-saving and cost-effective operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conveyance amount of the sheet is increased to prevent no-feed jams caused by slipping, then the reliability of sheet feeding is improved, but the size of the toothed gear and other components must be increased, leading to increased space requirements and cost
Solution Approach 1:
The support member is made rotatable in the vertical direction, allowing dynamic adjustment of the sheet feeding portion's position. This enables the system to adapt to variations in sheet thickness and feeding conditions without requiring oversized fixed components, thereby maintaining reliability while reducing space requirements.
Solution Approach 2:
The cam mechanism changes the position parameter of the sheet feeding portion by rotating the support member between a standby position (separated from the sheet) and a feeding position (abutting the sheet). This dynamic parameter change allows precise control of the feeding process without needing large marginal safety margins that would increase component size.
2Reliability
If the conveyance amount of the sheet is increased to prevent no-feed jams, then the reliability of sheet feeding is improved, but the cost of the device increases due to larger components
Solution Approach 1:
The rotatable support member enables dynamic positioning of the sheet feeding portion, allowing the use of smaller, more cost-effective components that can adapt their position rather than requiring large fixed components with built-in safety margins for slip prevention.
Solution Approach 2:
The cam mechanism replaces complex mechanical coupling systems (such as large toothed gears) with a simpler rotational mechanism that achieves the same function of controlling sheet conveyance, thereby reducing manufacturing cost while maintaining reliability.
3Reliability
If the sheet feeding portion is held at a standby position separated from the sheet, then slipping is prevented, but the sheet feeding response time is increased
Solution Approach 1:
The support member is pre-positioned at the standby position where the sheet feeding portion is separated from the sheet during non-feeding periods. This preliminary positioning prevents slipping and prepares the system for rapid activation when feeding is required, minimizing response time while maintaining reliability.
Solution Approach 2:
The support member alternates between the standby position (separated from sheet) and feeding position (abutting sheet) in periodic cycles. This periodic action allows the system to maintain reliability during idle periods while enabling rapid transition to feeding mode when needed, balancing slip prevention with response time.
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
The solution enables reliable sheet feeding while saving space and reducing costs by controlling the rotation speed and angle of the cam to prevent slips and ensure consistent sheet delivery, thereby minimizing no-feed jams.
Implementation Method 1
a cam which holds the sheet feeding portion at a standby position separated from the sheet by upwardly rotating the support member and moves the sheet feeding portion to a feeding position abutting the sheet by downwardly rotating the support member
Data Source
AI summary
When a sheet is determined to arrive at a registration roller, a motor is temporarily stopped and then, is rotated so as to return a cam to an initial position. When the motor is rotated, in a case where a relation between a rotation angle &thetas; of the cam at the time of stopping the motor and a rotation angle γ of the cam according to the rotation of the motor in a time required for the motor until acceleration up to constant-speed rotation from a stopped state of the motor and until deceleration from the constant-speed rotation and stop after the deceleration is “&thetas;<360−γ”, the motor is rotated at a first speed by controlling acceleration/deceleration of the motor and, in a case where the relation is “&thetas;>360−γ”, the motor is rotated at a constant second speed lower than the first speed.