Printer Star Wheel Holding Load Control for Label Ink Transfer
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Solution Overview
Problem
In printers, the use of star wheels to hold recording media can lead to decreased image quality due to protrusion traces and ink adhesion issues, especially when holding label sheets, as the holding load exceeds a safe threshold, causing ink transfer and image defects.
Innovation Solution
A printing apparatus with a star wheel unit that adjusts its holding load to be equal to or less than 4.5 gf when the recording medium's height is less than 2.2 mm from the support surface, using a hoisting and lowering unit to maintain optimal contact and prevent excessive pressure, thereby minimizing image defects and ink transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If star wheels are used to hold the recording medium with high holding load, then the recording medium can be securely held and transported, but image quality decreases due to protrusion traces and ink transfer
Solution Approach 1:
The patent applies parameter changes by adjusting the holding load of the star wheel to be equal to or less than 4.5 gf, and controlling the maximum height of the recording medium to be less than 2.2 mm. These specific parameter thresholds resolve the contradiction by finding the optimal balance between secure holding and preventing image quality degradation from excessive pressure.
2Reliability
If the holding load of the star wheel is increased, then the recording medium is held more securely, but adhesive adhesion to the star wheel protrusion increases causing ink transfer
Solution Approach 1:
The patent resolves this contradiction by establishing a maximum holding load threshold of 4.5 gf for the star wheel. This parameter control prevents the adhesive from adhering too strongly to the star wheel protrusion, thereby eliminating ink transfer while maintaining sufficient holding security for reliable medium transport.
3Reliability
If the star wheel protrusion contacts the recording medium with high force, then the medium is firmly held, but traces of the protrusion remain on the medium surface
Solution Approach 1:
The patent applies parameter changes by limiting the holding load to 4.5 gf or less, which prevents the star wheel protrusion from exerting excessive force that would leave traces on the recording medium surface. This maintains firm holding while preserving surface quality.
Data Source
AI summary
A printing apparatus includes: a printing head configured to discharge ink onto a recording medium to form an image; a platen including a support surface that supports the recording medium; and a recording medium holding portion being configured to hold a plurality of star wheels configured to hold the recording medium toward the support surface in a direction perpendicular to the support surface. In a case in which a maximum value of a height of the recording medium from the support surface in the direction perpendicular to the support surface is less than 2.2 mm when the recording medium passes between the support surface and the recording medium holding portion, a load of one of the star wheels for holding the recording medium with presence of the recording medium holding portion is equal to or less than 4.5 gf.