Sheet Feed Speed Measurement Using Reference Roller Rotation
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Solution Overview
Problem
Existing sheet conveying devices in image forming apparatuses face challenges in accurately measuring the conveying speed of sheets due to potential misalignment or interference when multiple sheets are fed, leading to reduced accuracy in conveying speed measurement.
Innovation Solution
A sheet conveying device with a lift portion, a sheet supply portion, and a detection portion that includes a first determination processing to assess execution conditions for measuring conveying speed, followed by a measurement processing to acquire speed information and a second acquisition processing to determine the conveying amount based on a predetermined reference amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple sheets are fed simultaneously, then productivity is improved, but measurement precision deteriorates due to misalignment and interference
Solution Approach 1:
The patent segments the sheet feeding process into distinct phases: a first sheet is fed alone for accurate measurement, followed by subsequent sheets being fed in sequence. The conveying member rotates by a predetermined reference amount between measurements, creating clear separation between measurement events and preventing interference from multiple sheets
Solution Approach 2:
The system performs preliminary determination processing to check execution conditions before executing measurement processing. This includes verifying that the conveying member has rotated by the reference amount and that the detection portion is ready, ensuring measurements are taken at optimal moments before subsequent sheets may cause interference
2Measurement precision
If conveying speed measurement is performed continuously, then measurement precision is improved, but device complexity increases due to multiple processing portions
Solution Approach 1:
The control portion serves multiple functions: it controls the conveying member rotation, manages the detection portion operation, performs determination processing to check execution conditions, and executes measurement processing to calculate conveying speed. This multi-functional approach avoids adding separate dedicated components for each function
Solution Approach 2:
The system uses the existing detection portion, originally designed for sheet detection, to also perform conveying speed measurement by detecting the sheet at specific timing. This self-service approach allows the same component to serve dual purposes without requiring additional specialized measurement devices
Data Source
AI summary
A sheet conveying device includes a sheet supply portion, a first acquisition processing portion, a measurement processing portion, and a second acquisition processing portion. The sheet supply portion includes a conveying member which rotates while being in contact with an upper surface of a stack of sheets lifted by a lift portion, and supplies a sheet in contact with the conveying member. The first acquisition processing portion acquires speed information regarding a conveying speed of the sheet. The measurement processing portion measures an elapsed time from a start of supply of the sheet by the sheet supply portion to when the sheet is detected by a detection portion after the conveying member is rotated by a reference amount. The second acquisition processing portion acquires a conveying amount of the sheet when the conveying member is rotated by the reference amount based on the acquired speed information and the elapsed time.