Duplex Printer Sheet Overlap for Compact Double-Sided Printing
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Solution Overview
Problem
Existing printing apparatuses face an increase in size due to the need for a longer conveyance path to accommodate double-sided printing, as they require a common intermediate roller that prevents overlapping of print media, leading to inefficiencies.
Innovation Solution
The apparatus includes separate intermediate rollers for conveying print media from the supply path to the printing unit and from the inversion path, allowing overlapping of print media in the conveyance path without increasing the overall apparatus size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common intermediate roller is used to convey print media from both supply path and inversion path, then the structure is simplified, but the print media cannot overlap and the conveyance path length must be larger than the maximum sheet length, leading to increased apparatus size
Solution Approach 1:
The invention divides the common intermediate roller into two separate intermediate rollers: a first intermediate roller for conveying print media from the supply path, and a second intermediate roller for conveying print media from the inversion path. This segmentation allows independent control of each conveyance path, enabling print media to overlap in the first conveyance path without increasing the overall apparatus size.
2Productivity
If the conveyance path length is made larger than the maximum sheet length to completely draw the first print medium into the inversion path, then the printing operation is complete, but the apparatus size increases
Solution Approach 1:
The invention introduces a second conveyance path that runs parallel to the first conveyance path. The second conveyance path conveys print media in the opposite direction (from inversion path to printing unit) while the first conveyance path conveys print media from supply path to printing unit. This dimensional arrangement allows print media to overlap in space without requiring extended conveyance path length, maintaining compact apparatus size while enabling continuous double-sided printing operation.
Data Source
AI summary
A printing apparatus includes a supply unit, a supply path, first and second conveyance paths, a printing unit, and an inversion roller. The first conveyance path conveys, to a first direction, a print medium. The printing unit prints an image on the two surface of the print medium. The inversion roller inverts a conveyance direction of the print medium and conveys the print medium in a second direction. The second conveyance path conveys the print medium conveyed in the second direction to the first conveyance path while inverting the print medium. When performing printing on both sides of print media, the print media are convey such that a first print medium supplied from the second conveyance path and a second print medium supplied from the supply path overlap in the first conveyance path.