Removable Printhead Wiper Unit With Negative-Bend Media Path

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Solution Overview

Problem

Existing printhead maintenance systems face inefficiencies in cleaning nozzle plates due to the need for frequent replacement of wiper rolls and the lack of a compact, efficient design for wiper units that can maintain consistent tension and fluid application during the wiping process.

Innovation Solution

A wiper unit with a housing and multiple rollers forming a negative bend path, including a force pinch mechanism and a lamellar roller, ensures consistent tension and efficient fluid application, allowing for swift loading and unloading, and features a locking mechanism for easy roll replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a roll of wiper medium is unspooled through a simple path inside the housing, then the structure is simple, but the wiper unit becomes bulky and difficult to load/unload

Engineering Contradiction:
Improvewiper unit sizeVSAvoidloading and unloading speed
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent applies a negative bend (curved path) in the wiper medium routing that extends outside the housing. This curvature allows the wiper medium to be exposed at strategic points for wetting while maintaining a compact housing footprint. The bent path enables efficient space utilization, making the wiper unit both compact and easy to handle during loading and unloading operations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If the wiper medium path is exposed outside the housing for wetting, then fluid application is improved, but the housing structure becomes more complex

Engineering Contradiction:
Improvefluid application efficiencyVSAvoidhousing structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The wiper medium path is segmented into different sections: portions that remain inside the housing for tension maintenance and portions that extend outside for wetting. This segmentation allows the housing to maintain its structural integrity while providing targeted exposure of only the necessary sections for fluid application, thereby balancing manufacturing efficiency with structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The negative bend extends the wiper medium path in a different spatial dimension (outside the housing) rather than complicating the internal housing structure. This dimensional change allows fluid application access without adding internal complexity to the housing, as the exposure is achieved through external routing rather than internal structural modifications.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If multiple rollers are used to define a negative bend path, then consistent tension is maintained, but the device complexity increases

Engineering Contradiction:
Improvewiping tension consistencyVSAvoidroller mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The negative bend created by the roller arrangement provides a curved path that naturally maintains tension on the wiper medium. The geometry of the bend itself contributes to tension consistency, reducing the need for additional complex tensioning mechanisms. The rollers are strategically positioned to create this beneficial curvature that passively maintains reliable wiping tension.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP4656390A1A removable wiper unit for a printhead maintenance unit
Publication Date: 2025.12.03 CANON KK
  • EP4656390A1 patent drawingFigure 1~3
  • EP4656390A1 patent drawingFigure 4~5
  • EP4656390A1 patent drawingFigure 6~7

AI summary

A compact and efficiently loadable wiper unit (70) for a maintenance unit (20) of a printer (1) is provided. The wiper unit (70) comprises a: - a housing (90); - a plurality of rollers (74-81), two rollers (74, 81) of which are configured for holding a roll (73, 82) of wound-up wiper medium (72), and wherein the remaining rollers (75-80) define a path for transporting the wiper medium (72) between said two rollers (74, 81), characterized in that the path defined by the rollers (74-81) comprises a negative bend, which negative bend extends at least partially outside the housing (90).