Manual Feed Tray Pickup Roller Positioning for First Copy Time
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Solution Overview
Problem
In image forming apparatuses, the first copy time is lengthened due to the delay in sheet feeding from a manual feed tray, as the pickup roller is raised unnecessarily each time, causing it to wait at an upper limit position before lowering to feed sheets, which increases the time to the sheet surface and results in vibration delays.
Innovation Solution
An image forming apparatus with a manual feed tray and a controller that determines if a sheet is present and of designated size, causing the sheet-feeding unit and manual feed tray to move closer, allowing the pickup roller to be positioned at the sheet surface before printing starts, thus eliminating unnecessary delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pickup roller is raised each time one sheet is fed from the manual feed tray, then the sheet feeding mechanism can reliably feed one sheet at a time, but the pickup roller waits at the upper limit position causing delay in sheet feeding operation
Solution Approach 1:
The controller determines whether a sheet is placed on the manual feed tray in advance and causes the pickup roller to be lowered to the sheet surface position before printing is started. This preliminary positioning eliminates the time delay that occurred when the pickup roller waited at the upper limit position, while still maintaining the reliability of feeding one sheet at a time through the original raising/lowering mechanism
2Loss of time
If the pickup roller is lowered to the sheet surface before printing starts, then the first copy time is shortened, but the mechanism complexity increases due to additional control requirements
Solution Approach 1:
The controller uses feedback from the sheet detection determination to control the pickup roller's position. The system determines whether a sheet is placed on the manual feed tray and uses this information to decide whether to lower the pickup roller to the sheet surface position in advance, creating a simple feedback-based control mechanism that reduces first copy time without excessive complexity
Data Source
AI summary
Provided is an image forming apparatus including a manual feed tray for placing a sheet subjected to image formation, a sheet sensor configured to detect whether or not the sheet is placed on this manual feed tray, a pickup roller configured to feed the sheet placed on the manual feed tray, and a controller. When a size of a sheet to be fed is designated by a user, and it is determined that the sheet is placed, the controller causes at least one of the pickup roller and the manual feed tray to start movement to a position of enabling the pickup roller to feed the placed sheet.