Optical Tray Position Detection for Printing Media Alignment

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Solution Overview

Problem

Existing printing apparatuses face issues with accurate placement of printing media on trays, leading to incorrect printing positions and potential staining of the apparatus due to user errors, as they do not account for shifts in the relative position between the tray and the printing medium.

Innovation Solution

A printing apparatus equipped with a conveyance unit, a printing unit, and a first detection unit to determine the relative position of the printing medium on the tray, along with a notification system to alert users of incorrect placement, preventing printing when the medium is not correctly positioned.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If tray conveyance mechanism is used for printing on rigid printing media, then printing capability on discs is achieved, but printing position shifts due to part accuracy variations and tray setting errors

Engineering Contradiction:

Improveprinting capability on rigid mediaVSAvoidprinting position accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical position detection methods with an optical detection system. A light source emits light toward the printing medium, and a photodetector measures the reflected light intensity to determine the printing medium's position and presence, eliminating mechanical measurement errors and improving positioning accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a reflection plate as an intermediary element between the light source and the photodetector. The reflection plate reflects light from the printing medium to the photodetector, enabling indirect detection of the printing medium's position and presence, which solves the problem of direct mechanical measurement inaccuracies.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If reflection plate is used to detect printing medium presence, then detection capability is improved, but false detection occurs when printing medium is about to come off or hidden

Engineering Contradiction:

Improveprinting medium presence detectionVSAvoiddetection accuracy under edge cases

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent performs preliminary detection of the printing medium's presence and position before initiating the printing process. The optical detection system checks whether the printing medium is correctly placed on the tray and is not about to come off, preventing printing operations from proceeding under unreliable conditions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the photodetector continuously monitors the light reflected from the printing medium, and the control unit adjusts or cancels printing operations based on the detection results. When the printing medium is detected to be in an unstable state (about to come off or hidden), the system provides feedback to prevent printing.

Inventive Principle:

Principle #23Feedback

3Productivity

If printing starts without checking printing medium placement, then productivity is maintained, but staining occurs inside the apparatus and tray due to user errors

Engineering Contradiction:

Improveprinting throughputVSAvoidstaining of apparatus and tray

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary detection of the printing medium's presence and correct placement before initiating printing operations. The optical detection system checks whether the printing medium is properly positioned on the tray, and only if detection is successful does the system proceed to printing, preventing staining caused by user errors.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the detection results are fed back to the control unit, which then decides whether to proceed with printing or cancel the operation. This feedback loop prevents staining by stopping printing operations when the printing medium is not correctly placed, while maintaining productivity when placement is correct.

Inventive Principle:

Principle #23Feedback

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

Prevents printing errors by ensuring the printing medium is correctly placed on the tray, thereby avoiding stains within the apparatus and maintaining printing accuracy.

Implementation Method 1

an optical sensor that detects the printing medium by detecting light from the tray surface

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS11053089B2Printing apparatus, control method thereof and storage medium

Publication Date: 2021.07.06 CANON KK

AI summary

A printing apparatus includes a conveyance unit configured to convey a tray on which a printing medium is placed, a printing unit configured to perform printing on a print surface of a printing medium on the tray based on a print job, and a first detection unit configured to detect a relative position relationship between the tray and a printing medium placed on the tray. In addition, a control unit is configured to control the printing unit not to perform printing in a case where the first detection unit detects that the printing medium is not placed at an appropriate position, and a selecting unit is configured to select whether to continue printing irrespective of results of the detection by the first detection unit.