Sheet Conveyance Shape Detection During Roller Speed Transitions
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Solution Overview
Problem
Existing sheet conveyance systems in image forming apparatuses face challenges in accurately detecting sheet shape and rotation speed, leading to reduced accuracy in sheet shape detection and increased risk of ink adhering to the conveyance belt, especially when the registration roller transitions between acceleration and deceleration states.
Innovation Solution
A sheet conveyance device equipped with a first conveyance member, a shape detecting portion, a speed detecting portion, and a switch control portion, where the shape detecting portion uses light emission and reception to detect sheet shape and the speed detecting portion determines the conveyance member's state, adjusting the output interval of the detection signal accordingly to synchronize with the rotation speed, ensuring accurate shape detection and preventing ink adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the registration roller is driven while decelerated in a stepped manner, then productivity is improved by reducing the interval to the conveyed preceding sheet, but measurement precision deteriorates due to difficulty in detecting sheet shape and rotation speed during state transitions
Solution Approach 1:
The patent applies dynamics by making the detection signal output interval variable rather than fixed. The switch control portion dynamically adjusts the output interval based on the rotation speed detected by the speed detecting portion, allowing the system to adapt to changing conveyance conditions during acceleration and deceleration phases. This resolves the contradiction by enabling accurate sheet shape detection even when the registration roller operates with variable speed for improved productivity.
Solution Approach 2:
The patent implements feedback by using the speed detecting portion to continuously monitor the rotation speed of the registration roller and feeding this information back to the switch control portion. The switch control portion then adjusts the detection signal output interval based on this feedback, creating a closed-loop control system that maintains measurement precision despite changes in conveyance speed for productivity improvement.
2Device complexity
If the detection signal output interval is fixed, then device complexity is reduced, but measurement precision deteriorates during acceleration and deceleration states
Solution Approach 1:
The patent makes the detection signal output interval dynamic by switching between a first interval during acceleration and a second interval during deceleration. This dynamic adjustment maintains measurement precision without requiring overly complex control systems, as the switch control portion only needs to respond to clearly defined acceleration and deceleration states detected by the speed detecting portion.
3Ease of operation
If the light receiving portion outputs detection signals at a fixed interval, then ease of operation is improved, but reliability deteriorates due to reduced detection accuracy during speed transitions
Solution Approach 1:
The patent uses feedback from the speed detecting portion to automatically adjust the detection signal output interval. This maintains reliability during speed transitions without requiring manual intervention or complex operation, as the switch control portion automatically responds to changes in registration roller speed state, keeping the system easy to operate while ensuring accurate detection.
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 enhances the accuracy of sheet shape detection and reduces the risk of ink adherence to the conveyance belt by synchronizing the detection signal output with the registration roller's speed, maintaining detection precision even during state transitions, thus improving the overall efficiency and reliability of the image forming process.
Implementation Method 1
The light emitting portion emits light toward a detection position located between the first conveyance member and the image forming position in the conveyance path, the light extending in a width direction of the sheet perpendicular to the conveyance path. The light receiving portion receives the light that has been emitted from the light emitting portion and reflected on the sheet passing the detection position
Data Source
AI summary
A sheet conveyance device includes a shape detecting portion, and a switch control portion. The shape detecting portion detects a shape of a sheet at a detection position located between a first conveyance member and an image forming position in a sheet conveyance path. The switch control portion, when the first conveyance member is determined to be in an accelerated state where it is accelerated from a stopped state to a driven state, switches an detection interval at which the shape of the sheet is detected by the shape detecting portion, to a first interval that corresponds to a rotation speed of the first conveyance member, and when the first conveyance member is determined to be in a decelerated state where it is decelerated from the driven state to the stopped state, switches the detection interval to a predetermined second interval.