Inkjet Head Gap Adjustment Using Rotating Stepped Cam
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Solution Overview
Problem
Existing inkjet recording apparatuses face challenges in optimizing the distance between the sheet and the inkjet head, leading to issues such as print position shifts, color shifts, increased size, and reduced durability due to mechanical impacts and complex configurations.
Innovation Solution
The apparatus incorporates a gap adjustment device with a shaft, rotating member, stepped part, gap adjustment member, and spherical bodies to adjust the gap between the inkjet head and the conveyance path, allowing for precise alignment without increasing the apparatus size or causing mechanical impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a member is provided in contact with the sheet to lift the inkjet head, then the gap adjustment is achieved, but a load is applied on the sheet conveyance causing conveyance speed change and print position shift
Solution Approach 1:
A contactless coupling mechanism using magnetic fields or electric fields is introduced as an intermediary between the inkjet head and the sheet. This allows the inkjet head to be positioned at the correct gap without physically contacting the sheet, thereby avoiding load application and conveyance speed changes while maintaining gap adjustment precision.
Solution Approach 2:
The mechanical contact-based gap adjustment system is replaced with a non-contact system using electromagnetic fields. The inkjet head position is controlled through field-based coupling rather than physical contact, eliminating the harmful mechanical load on the sheet conveyance system.
2Manufacturing precision
If the inkjet head is mounted on a stepped member to adjust height, then the gap can be adjusted, but the apparatus size increases due to required stroke space
Solution Approach 1:
The gap adjustment mechanism transitions from linear stroke movement in one dimension to rotational movement in a different dimension. The inkjet head is rotated around a shaft to achieve height adjustment, eliminating the need for large linear stroke space and reducing overall apparatus volume while maintaining adjustment capability.
Solution Approach 2:
The static stepped member structure is replaced with a dynamic rotational mechanism. The inkjet head can dynamically adjust its position by rotating around a shaft, allowing compact packaging of the adjustment mechanism without requiring fixed stroke space.
3Manufacturing precision
If the inkjet head gets over the step of the stepped member, then height adjustment is achieved, but mechanical impact occurs reducing durability
Solution Approach 1:
The sharp stepped edges are replaced with curved surfaces. The inkjet head contacts a curved surface that gradually transitions in height, allowing smooth rolling or gliding motion without sudden impacts. This curvature eliminates mechanical shock while achieving the required height adjustment.
Solution Approach 2:
A cushioning mechanism is introduced before the height adjustment transition. This could be a spring-loaded support or a compliant material layer that absorbs the impact energy when the inkjet head transitions between different height levels, protecting the mechanical structure from damage.
4Strength
If the inkjet head is temporarily retracted to avoid impact, then durability is improved, but the time required for retraction and return delays printing start
Solution Approach 1:
The inkjet head positioning system is designed to allow continuous operation without interruption. The rotational or curved surface adjustment mechanism enables the inkjet head to change height continuously during sheet conveyance without needing to retract and return, maintaining continuous printing action and eliminating time delays.
5Manufacturing precision
If the stepped member reciprocates to adjust height, then gap adjustment is achieved, but impact due to gear backlash is generated
Solution Approach 1:
The gear-driven reciprocating mechanism is replaced with a direct rotational mechanism. The inkjet head rotates around a shaft to achieve height adjustment, eliminating the need for gears and backlash. This substitution removes the source of mechanical impact while maintaining precise adjustment capability.
Data Source
AI summary
An inkjet recording apparatus includes a head unit and a gap adjustment device. The head unit includes one or more inkjet heads. The gap adjustment device adjusts a gap of the head unit with respect to a conveyance path. The gap adjustment device includes a shaft, a rotating body, a stepped part, a gap adjustment member, a spherical body. The rotating member has an intersection surface intersecting the shaft and is rotatable around the shaft. The stepped part is provided on the intersection surface and its height is changed in a stepped pattern in a circumferential direction. The gap adjustment member has a rear side surface facing the intersection surface and a front side surface being in contact with the head unit, and is movable in a direction of the shaft. The spherical body is held between the rear side surface and the intersection surface.