Duplex Printer Guide Path for Faster Sheet Reversing

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Solution Overview

Problem

Existing duplex printers take a long time to transport cut sheets, hindering high-speed printing operations.

Innovation Solution

A duplex printer design featuring a guide transport path with a stopper and switcher, a reversing mechanism connected via a switcher, and a discharge path branching from the stopper, along with a compact reversing mechanism housed below the switcher, to efficiently transport and reverse cut sheets for duplex printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a reversing mechanism is used to enable duplex printing, then printing functionality is improved, but transport time increases

Engineering Contradiction:

Improveduplex printing functionalityVSAvoidtransport time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The transport path is segmented into distinct functional zones: a first transport path for feeding sheets to the printing unit, a second transport path for returning sheets to the reversing mechanism, and a discharge path for output. This segmentation allows independent optimization of each path and enables parallel operations during duplex printing cycles.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stopper is positioned in advance in the first transport path to hold the next sheet ready before the current sheet completes its round trip. This preliminary positioning eliminates waiting time and ensures continuous operation by having the next sheet prepared and positioned for immediate processing.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the reversing mechanism is disposed far from the printing unit, then reversing function is improved, but transport time increases

Engineering Contradiction:

Improvereversing functionVSAvoidtransport time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The reversing mechanism is positioned below the printing unit in a vertical arrangement rather than horizontally distant. This dimensional reorganization allows the reversing mechanism to be integrated into the vertical space beneath the printing unit, reducing horizontal transport distance while maintaining reversing functionality.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Device complexity

If the distance between switcher and stopper is increased, then component arrangement is improved, but transport speed decreases

Engineering Contradiction:

Improvecomponent arrangementVSAvoidtransport speed

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

The stopper and switcher are merged into a single integrated component assembly positioned closely together in the first transport path. This merging minimizes the distance between them, allowing the stopper to quickly release sheets to the switcher without significant transport delay, thus maintaining high transport speed while keeping the component arrangement compact.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12358303B2Duplex printer

Publication Date: 2025.07.15 DAI NIPPON PRINTING CO LTD

AI summary

[Object] To reduce the time required to transport a cut sheet and perform printing at a high speed.[Solution] A duplex printer 10 includes a printing unit 12A, a cut sheet feeder 25, and a guide transport path 24. A reversing mechanism 20 that reverses a cut sheet 1 returned from the printing unit 12A is connected to the guide transport path 24 via a switcher 61. A stopper 62 that stops the cut sheet 1 is provided in a part of the guide transport path 24 on the upstream side of the switcher 61. A discharge path 65 branches off from the stopper 62 of the guide transport path 24.