Eccentric Pin Printhead Alignment Mechanism

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Solution Overview

Problem

In inkjet page-wide printers, the accurate spacing between printheads is crucial to prevent print quality defects such as visible strikes and line artifacts, but as the span of the printhead assembly increases, errors in spacing lead to an increase in defective printheads due to manufacturing tolerances.

Innovation Solution

The use of a pin assembly with eccentric pins that rotate to adjust the position of printheads relative to the printbar beam member, allowing for precise alignment and reduction of spacing errors, thereby minimizing print quality defects and defective printheads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the span of the printhead assembly increases to accommodate wider media, then the printing capability is improved, but the spacing errors between printheads increase due to manufacturing tolerances

Engineering Contradiction:

Improveprint zone widthVSAvoidspacing accuracy

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies the dynamics principle by making the printhead position adjustable rather than fixed. The adjustment mechanism allows the printhead to be moved along the printbar beam member to compensate for spacing errors, transforming a static manufacturing tolerance problem into a dynamic calibration solution.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the position parameter of the printhead relative to the printbar beam member. By allowing the printhead to be repositioned to different locations along the beam, the system can adjust the spacing between printheads to correct for manufacturing errors and maintain accurate printing.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If fixed mounting is used to simplify assembly, then the device complexity is reduced, but the ability to correct spacing errors is lost

Engineering Contradiction:

Improvemounting structureVSAvoidprinthead spacing

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The mounting structure transitions from a completely fixed design to a semi-dynamic design where the printhead can be adjusted to a specific position and then secured. This provides the flexibility needed to correct spacing errors while maintaining structural stability during operation.

Inventive Principle:

Principle #15Dynamics

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

This solution effectively reduces print quality defects and the number of defective printheads by enabling precise adjustment of printhead positions, maintaining print quality even as the span of the printhead assembly increases.

Implementation Method 1

The pin assembly includes an eccentric pin configured to rotate to adjust a position of the printhead relative to the printbar beam member

Methodology Applied

Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP2918411B1Adjustment of a position of a printhead relative to a printbar beam member

Publication Date: 2019.07.24 HP SCITEX LTD

Figure 1
Figure 2A~2B
Figure 3

AI summary

A printhead assembly, a printhead alignment tool usable with a printhead assembly, and a method of aligning a misaligned printhead are disclosed. The printhead assembly includes a printhead disposed on a printbar beam member. A position of the printhead may be adjusted relative to a printbar beam member.