Sheet Feeding Timing Control for Consistent Conveyance Intervals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining a consistent conveyance interval between sheets due to variations in sheet length during duplex image formation, leading to inconsistent printing quality.
Innovation Solution
The apparatus includes sensors to detect sheet passage and a controller that adjusts the feeding timing of subsequent sheets based on the passing time of preceding sheets, ensuring a consistent interval by determining an adjustment time period to synchronize sheet feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sheet feeding timing is controlled based on sheet size detected before image formation, then the conveyance interval between successive sheets can be optimized, but the interval varies when sheet size information is not acquired
Solution Approach 1:
The system performs preliminary detection of sheet passage through sensors before image formation begins. The first sensor detects the leading end and trailing end of the preceding sheet in advance, allowing the controller to calculate the actual sheet length and determine the adjustment time period before the subsequent sheet needs to be fed, ensuring consistent intervals even when initial sheet size information is unavailable
Solution Approach 2:
The system uses feedback from the first sensor detecting the actual passage time of the preceding sheet to dynamically adjust the feeding timing of the subsequent sheet. The controller continuously monitors the time from when the leading end to when the trailing end of the preceding sheet passes through the first sensor, and uses this feedback to determine the optimal adjustment time period for maintaining consistent conveyance intervals
2Adaptability or versatility
If duplex image formation is performed with re-conveyance, then both sides of sheets can be printed, but the conveyance interval varies due to differences in sheet length between preceding and subsequent sheets
Solution Approach 1:
Before the subsequent sheet is fed after re-conveyance, the system preliminarily detects the trailing end of the preceding sheet through the first sensor and calculates the adjustment time period in advance. This preliminary action ensures that even though sheets may have different lengths, the subsequent sheet will be fed at the correct time to maintain consistent conveyance intervals through the image forming unit
Solution Approach 2:
The system implements feedback control by monitoring the actual passage time of the preceding sheet through the first sensor during re-conveyance operations. The controller uses this feedback information about the preceding sheet's length and passage time to dynamically adjust the feeding timing of the subsequent sheet, ensuring consistent intervals despite variations in sheet dimensions
Data Source
AI summary
An image forming apparatus including a first sensor configured to output a signal in response to detecting passage of each sheet fed by a sheet feeder, a second sensor configured to output a signal in response to detecting passage of each sheet re-conveyed by a re-conveyance unit, and a controller configured to acquire a passing time period during which a preceding sheet fed by the sheet feeder is passing through the first sensor, based on the signal from the first sensor, determine an adjustment time period between a time when a leading end of the preceding sheet re-conveyed by the re-conveyance unit is detected based on the signal from the second sensor and a time for the sheet feeder to feed a subsequent sheet toward the image forming unit, and control the sheet feeder to feed the subsequent sheet toward the image forming unit with timing adjusted based on the determined adjustment time period.