Thermal Transfer Printer Tension Member Curvature
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Solution Overview
Problem
Thermal-transfer printers with tension members having a curved shape where the center protrudes more than the edges in the width direction can generate printing unevenness in the form of perforation near the center of the print, and cause damage to the image-receiving sheet and wrinkles in the ink ribbon during separation.
Innovation Solution
A method for producing prints using a thermal-transfer printer with a tension member that has a curved shape with the center protruding 0.4 to 2 mm more than the edges in the width direction, combined with an ink ribbon having a color material layer and a protection layer, and an image-receiving sheet with a receptor layer, where the dynamic friction coefficient between the receptor layer and the protection layer is 0.4 or less, to prevent separation damage and wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tension member with a curved shape (center protruding more than edges) is used to stretch the ink ribbon, then the ink ribbon separation from the image-receiving sheet is improved, but printing unevenness in the form of perforation near the center is generated
Solution Approach 1:
The patent applies local quality by creating a curved surface on the tension member where the center protrudes more than the edges in the width direction. This non-uniform local geometry allows the center portion to contact the ink ribbon first during separation, generating a gradient in contact pressure and tension distribution across the width of the ribbon. The curved shape is specifically designed with the center protruding 0.4 to 2 mm more than the edges, creating localized differences in mechanical interaction that facilitate progressive separation from center to edges, thereby resolving the contradiction between reliable separation and printing uniformity.
2Strength
If the center of the tension member protrudes more than the edges, then the ink ribbon is tightly stretched, but damage to the image-receiving sheet and wrinkles in the ink ribbon occur during separation
Solution Approach 1:
The patent employs spheroidality (curvature) by forming the tension member surface with a curved profile where the center protrudes more than the edges in the width direction. This curved geometry creates a progressive contact mechanism during separation: the center portion contacts the ink ribbon first and applies tension gradually, while the edges contact later. This curved contact pattern distributes the separating force more evenly across the ribbon width, preventing concentrated stress that would cause sheet damage or ribbon wrinkles, while still achieving the necessary tight stretching for effective separation.
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 method prevents damage to the image-receiving sheet and reduces printing unevenness, ensuring high-quality prints without wrinkles or perforation issues.
Implementation Method 1
dyes contained in the ink ribbon are transferred to the image-receiving sheet by applying heat from the thermal head to the ink ribbon
Implementation Method 2
a tension member for tightly stretching the ink ribbon in the downstream of a printing position
Implementation Method 3
the dynamic friction coefficient between the receptor layer surface of the image-receiving sheet before being coated with the protection layer and the outermost surface on the protection layer of the ink ribbon, is 0.4 or less
Data Source
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AI summary
The present invention is to provide a method for producing a print, which is able to prevent damages to the image-receiving sheet upon separation of the ink ribbon and generation of large wrinkles at the edges of the ink ribbon upon printing, to reduce printing unevenness that is generated intermittently in the form of perforation and near the center of the print, and thus to provide a high-quality print. Disclosed is a method for producing a print, in which a print is made on an image-receiving sheet by use of a thermal-transfer printer and an ink ribbon, wherein, the thermal-transfer printer comprises a tension member for tightly stretching the ink ribbon in the downstream of a printing position disposed between a thermal head and a platen roller; the surface of the tension member facing the ink ribbon has a curved shape whose center in the width direction is protruding 0.4 to 2 mm in the flow direction of the ink ribbon, more than the edges in the width direction; the ink ribbon has at least one color material layer and a protection layer; the image-receiving sheet has a receptor layer; and after printing all colors of the color material layers, the dynamic friction coefficient between the receptor layer surface of the image-receiving sheet before being coated with the protection layer and the outermost surface on the protection layer of the ink ribbon, is 0.4 or less.