Professional barcode scanning equipment is the fundamental tool for inspection. It's essential to choose models with high resolution and strong decoding capabilities, such as industrial-grade scanners that support both 1D and 2D barcode recognition. These devices can accurately capture the differences in reflectance between bars and spaces in the barcode paper, avoiding misreading due to insufficient hardware performance. For example, high-precision scanning equipment can clearly distinguish subtle bar width deviations caused by printing processes in barcode paper, providing reliable data for subsequent analysis.
The inspection method must combine international standards with the actual scenario, analyzing parameters such as symbol contrast, modulation ratio, and edge contrast through scanning reflectance curves. Symbol contrast reflects the degree of contrast between bars and spaces, while the modulation ratio measures the stability of the bar-space width ratio. Edge contrast affects the scanning equipment's accuracy in recognizing barcode boundaries. For example, if the symbol contrast of the barcode paper is insufficient, the scanning equipment may be unable to decode accurately due to low bar-space differentiation.
Environmental factors significantly affect the inspection results. Excessive or insufficient light can distort the scanning reflectance curve; therefore, inspection must be conducted under constant lighting conditions, avoiding direct sunlight or shadow interference. Temperature and humidity are equally critical. High temperatures can deform barcode paper, while high humidity can cause paper swelling or ink bleeding, leading to bar width deviations. For example, in a humid environment, the edges of barcode paper may become blurred due to water absorption and swelling, reducing the scanning recognition rate.
Sample diversity is key to verifying accuracy. Barcode paper samples of different sizes, densities, and colors should be prepared, including high-density small-size barcodes and low-density large-size barcodes, to test the scanning device's adaptability to complex scenarios. Simultaneously, damaged samples should be introduced, such as slightly soiled, wrinkled, or partially missing barcode paper, to assess the scanning device's fault tolerance under non-ideal conditions. For example, if the scanning device can accurately recognize slightly wrinkled barcode paper, it indicates high practical application value.
Multiple verifications improve the reliability of results. Verifying the recognition stability of barcode paper through multiple scans from different angles avoids misjudgments caused by the randomness of a single scan. For example, performing ten scans on the same batch of barcode paper; if the recognition results are consistent, it indicates stable quality; if multiple misreads occur, the printing process or paper material should be investigated. Defect assessment should focus on the physical characteristics of the barcode paper. Defect level is a crucial indicator of barcode paper quality, including stains, scratches, and deformation. Lower defect levels result in higher scanning accuracy. For example, ink smears or uneven ink distribution on the barcode paper surface may cause the scanning equipment to misread the width of the bars, thus affecting the decoding results.
Comparison with standard samples is the final step in verifying barcode paper quality. The tested barcode paper is compared with standard samples in parameters such as appearance, size, and reflectivity to ensure compliance with industry standards. For example, if the barcode paper's bar width deviation exceeds the standard's allowable range, or if the reflectivity curve differs significantly from the standard sample, the printing process needs adjustment or the paper material needs to be replaced.
