Sheet Discharging Roller Reversal for Compact Double-Sided Printing
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Solution Overview
Problem
Image forming apparatuses that can form images on both sides of a sheet require a conveying path to reverse the sheet's direction, leading to increased external dimensions, which is undesirable.
Innovation Solution
Incorporating a sheet discharging roller that can switch between discharging the sheet to a tray and re-conveying it back to the image forming section, along with a re-conveying roller positioned parallel to the conveying roller, allowing for image formation on both sides with reduced external dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conveying path is added to reverse the sheet's direction for double-sided image formation, then the ability to form images on both sides of the sheet is improved, but the external dimensions of the apparatus increase
Solution Approach 1:
The sheet discharging roller is designed to perform multiple functions: it can discharge sheets to the sheet discharging tray in normal operation, and it can also rotate in reverse to convey sheets back to the image forming section for double-sided image formation. This multi-functionality eliminates the need for a separate reversing conveying path, thereby maintaining compact external dimensions while enabling double-sided printing capability
Solution Approach 2:
Instead of adding a separate conveying path to reverse the sheet direction, the invention utilizes the existing sheet discharging roller and inverts its rotation direction. By rotating the roller in the opposite direction, the sheet is conveyed back toward the image forming section, achieving the reversing function without requiring additional conveying components or increasing the apparatus external dimensions
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
Enables the formation of images on both sides of a sheet while minimizing the apparatus's external dimensions by efficiently reversing the sheet's conveying direction without increasing the device's size.
Implementation Method 1
an electrophotographic image forming section that forms an image on a sheet
Implementation Method 2
a conveying roller that conveys the sheet to the image forming section
Implementation Method 3
a sheet discharging roller that is switched between a first state in which the sheet discharging roller rotates in a first direction in which the sheet is discharged to the sheet discharging tray and a second state in which the sheet discharging roller rotates in a second direction in which the sheet is conveyed back toward the image forming section
Implementation Method 4
a re-conveying roller that conveys the sheet conveyed back toward the image forming section by the sheet discharging roller
Data Source
AI summary
An image forming apparatus includes: an electrophotographic image forming section; a sheet feeding tray; a conveying roller; a sheet discharging tray; a sheet discharging roller that is switched between a first state in which the sheet discharging roller rotates in a first direction and a second state in which the sheet discharging roller rotates in a second direction in which the sheet is conveyed back toward the image forming section; and a re-conveying roller that conveys the sheet conveyed back toward the image forming section by the sheet discharging roller, the re-conveying roller having an axial direction parallel to an axial direction of the conveying roller and being located at a position at which the re-conveying roller projected onto a first virtual plane that is perpendicular to the axial direction at least partially overlap with the conveying roller projected onto the first virtual plane.