Identifying the quality of the small roll of thermal label paper can be considered from the following aspects:
First, appearance inspection
1. Color and gloss:
Better quality thermal paper is usually slightly green, rather than too white or too bright. Too white paper may add too much phosphor, affecting the effect of use.
Paper finish should be moderate and uniform, no obvious color difference or color bias phenomenon. Excessive surface reflected light may also be a manifestation of excessive phosphor addition, poor quality.
2. Coating uniformity:
Observe whether the paper surface coating is uniform, no bubbles, impurities, color difference, crease and other obvious defects. Uneven coating can affect print quality and storage time.
The edge of the paper should be cut neatly, without burring, which is also an important indicator to measure the quality of the paper processing.
Second, physical performance testing
1. Thickness and size:
The thickness of the thermal paper should meet the design requirements, and the error should not exceed ±5%. It can be measured using a paper thickness meter.
In terms of size, pay attention to whether the actual diameter of the paper roll is consistent with the mark on the packing box, to avoid the merchant's shortfalls. The width and diameter of the paper roll directly affect the use effect and cost performance.
2. Strength test:
The strength of the paper includes tensile strength, tear strength and folding resistance, which can be measured by equipment such as tensile testing machines. Good quality thermal paper should have a high strength to ensure stability and durability.
Third, thermal performance detection
1. Color density and thermal sensitivity:
Spectrophotometer was used to measure the optical density of the color developing region and evaluate the color developing effect of the thermal paper.
The sample is placed on the constant temperature heater to set different temperatures for heating test, record the color rendering effect at each temperature, and evaluate the thermal sensitivity of the thermal paper. Good quality thermal paper should be able to produce color quickly and clearly at low temperatures.
2. Preservation and durability:
The preservation performance of thermal paper is evaluated through accelerated aging tests (such as high temperature, high humidity, ultraviolet light and other conditions). Good quality thermal paper should be able to maintain color stability for a long time, and it is not easy to fade or turn yellow.
Perform friction and chemical resistance tests to evaluate the wear and chemical resistance of thermal paper. These indicators are crucial to the durability and stability of the label paper in actual use.
Fourth, simple identification method
1. Fire roasting method:
Heat the back of the paper with a lighter and observe the color change after heating. Good quality thermal paper should be black and green (with a little green) after heating, and the color block is uniform, and the color gradually fades from the center to the four sides. If it appears brown or has fine stripes and uneven color blocks after heating, it indicates that the heat-sensitive formula is unreasonable or the coating is not uniform, and the storage time may be shorter.
2. Comparison and identification of sunlight exposure:
The printed paper is daubed with a highlighter and placed in the sun to accelerate the reaction of the heat-sensitive coating to light. Which paper turns black the fastest indicates the shorter the shelf life. Although this method is simple, it has certain reference value.
Fifth, precautions
When selecting thermal label paper, in addition to paying attention to the above aspects, it should also consider its applicable environment and equipment requirements. Different industries and scenarios may have different performance requirements for thermal labels.
During use, pay attention to reducing the number of times, avoid direct contact with the mouth and food, and wash hands in time to reduce potential health risks.
To sum up, the quality of the small roll of thermal label paper needs to be comprehensively considered and tested from many aspects. The quality level of thermal label paper can be effectively evaluated by means of appearance inspection, physical performance detection, thermal performance detection and simple identification method.