Encoder Scale Engagement Mechanism for Printer Carriage Stability

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Solution Overview

Problem

Ink jet printers face issues with encoder scale deviation from the detection sensor due to sheet jamming or varying printing medium thickness, leading to movement control breakdowns and potential encoder scale dislodgment from the encoder slit.

Innovation Solution

A printing apparatus with an encoder scale that engages with a frame through an engagement section, including an engagement hole portion and a hook-like engagement portion, prevents movement and bending, ensuring the encoder scale remains within the encoder slit, utilizing an elastic member for secure engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the encoder scale is fixed to the printer main body frame and the carriage moves vertically to accommodate different printing medium thicknesses, then the printer can handle various printing media, but the encoder scale may come out from the encoder slit more easily

Engineering Contradiction:

Improveability to print on various printing mediaVSAvoidencoder scale position stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The encoder scale is segmented into multiple sections: a fixed portion attached to the printer main body frame and a movable portion that can move vertically with the carriage. This segmentation allows the fixed portion to maintain positional stability while the movable portion accommodates different printing medium thicknesses, resolving the contradiction between adaptability and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An intermediary structure (the movable portion of the encoder scale) is introduced between the fixed frame and the moving carriage. This intermediary allows relative movement between the carriage and frame while maintaining the encoder scale's engagement with the encoder slit, enabling both vertical movement for different media thicknesses and stable positioning during operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the encoder slit is formed with a bag-like shape to prevent the encoder scale from coming out, then the encoder scale position stability improves, but the slit space in the lower portion may interrupt the encoder scale during vertical movement

Engineering Contradiction:

Improveencoder scale position stabilityVSAvoidencoder scale movement range

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The encoder scale is divided into fixed and movable portions, allowing the movable portion to extend vertically without being constrained by a bag-like encoder slit. This segmentation enables sufficient movement range for thick printing media while maintaining position stability through the engagement structure between the encoder scale and encoder slit.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of preventing encoder scale movement in the vertical dimension through a bag-like encoder slit, the solution allows movement in the vertical dimension while maintaining engagement in the horizontal dimension. The encoder scale can move vertically to accommodate different media thicknesses while remaining engaged with the encoder slit laterally, resolving the contradiction between movement range and position stability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If a guide member engages the encoder scale between both sides to correct relative position, then the encoder scale deviation is prevented, but the device complexity increases

Engineering Contradiction:

Improveencoder scale position accuracyVSAvoidencoder scale engagement structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The encoder scale engagement structure is merged with the existing frame and carriage components. The fixed portion of the encoder scale is attached to the frame while the movable portion is integrated with the carriage, combining the positioning and movement functions into a unified structure without requiring separate guide members, thereby reducing device complexity while maintaining position accuracy.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The encoder scale's own structure provides the positioning and movement functions. The fixed portion attached to the frame and the movable portion integrated with the carriage work together to automatically maintain proper alignment during vertical movement, eliminating the need for additional guide members or correction mechanisms and reducing overall device complexity.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9085181B2Printing apparatus

Publication Date: 2015.07.21 SEIKO EPSON CORP

AI summary

A printing apparatus includes: a carriage mounting print head, executing scanning in a direction perpendicular to a transport direction of a printing medium, and being movable in a vertical direction in accordance with the thickness of the printing medium; an encoder scale having a predetermined pattern and extending in the direction perpendicular to the transport direction; a detection sensor detecting the pattern of the encoder scale and including a slit into which the encoder scale is inserted; and a frame shaft-supporting a transport roller transporting the printing medium. The encoder scale stretches in the frame and a predetermined portion of the encoder scale in the extension direction engages with the frame through an engagement section.