Conveying Device Sagging Control for Double-Feed Detection
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Solution Overview
Problem
Inkjet printers face challenges in accurately detecting double-feed of sheets due to varying sagging of sheets between registration rollers and belt conveyor sections, leading to inconsistent light reception and false detection, which affects productivity.
Innovation Solution
A conveying device with a controller that adjusts the speed difference between conveyor units to form predetermined sagging, a light emitting and receiving unit to measure light passing through the sheet, and a storage unit to set a double-feed criterion, determining double-feed based on consistent light differences across conveying distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the conveying speed of the sheet is increased to eliminate the influence of registration rollers, then the sheet conveyance is improved, but sagging is formed on the sheet between registration rollers and belt conveyor section
Solution Approach 1:
The controller changes the conveying speed parameter dynamically. Specifically, the controller sets the conveying speed of the sheet conveyed by the registration rollers to be higher than the conveying speed of the sheet conveyed by the belt conveyor section, creating a speed difference that forms sagging at a predetermined position and direction
2Adaptability or versatility
If various kinds of sheets are used and external environment conditions change, then the adaptability is improved, but the sagging of the sheet becomes non-uniform and difficult to control
Solution Approach 1:
The optical sensor detects the actual sagging state of the sheet by measuring light transmission through the sheet. The controller uses this feedback information to adjust the conveying speeds of the registration rollers and belt conveyor section, thereby controlling the sagging position, direction, and level to be uniform despite variations in sheet types and environmental conditions
3Adaptability or versatility
If the level or direction of sagging is changed to accommodate different sheets, then the adaptability is improved, but the positional relationship between optical sensor and sheet changes causing false detection
Solution Approach 1:
The controller changes the operational parameters (conveying speeds) to maintain a predetermined sagging configuration. By dynamically adjusting the speed difference between registration rollers and belt conveyor section, the system ensures sagging occurs at a consistent position and direction, keeping the optical sensor's measurement conditions stable and preventing false detection
4Ease of operation
If the optical sensor detects double-feed based on absolute difference threshold, then the detection simplicity is improved, but false detection occurs when received light amount varies due to sagging direction
Solution Approach 1:
The optical sensor continuously measures the amount of light received through the sheet, providing feedback on the sheet's transmission characteristics. The controller uses this feedback to dynamically adjust the conveying speeds, ensuring the sheet maintains a predetermined sagging state that provides consistent light transmission, thereby eliminating false detection while maintaining simple detection logic
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
This solution reduces false detection of double-feed by ensuring consistent light measurement and averaging multiple readings, thereby enhancing the accuracy and reliability of sheet detection.
Implementation Method 1
a light emitting part emitting light to the conveying path and a light receiving part disposed so as to face the light emitting part with the conveying path interposed therebetween and receiving the light emitted from the light emitting part
Implementation Method 2
receiving the light emitted from the light emitting part, and acquires the amount of light, which passes through the printing medium conveyed along the conveying path and is received by the light receiving part
Data Source
AI summary
There is provided a conveying device including a controller that makes a conveying speed of a printing medium conveyed by a first conveyor unit be higher than a conveying speed of a printing medium conveyed by a second conveyor unit and makes the printing medium be conveyed while forming sagging on the printing medium between the first and second conveyor units. The controller makes a sheet sensor acquire the amount of light, which passes through the printing medium conveyed between a light emitting part and a light receiving part, as the amount of received light and determines whether or not the double-feed of the printing media has occurred only when this amount of received light is smaller than the double-feed criterion amount of received light at substantially the same conveying distance of the printing medium conveyed by the first conveyor unit.