Cigarette label, also known as cigarette box, cigarette skin, cigarette bag, cigarette shell, cigarette paper, etc., namely cigarette trademark, is the direct packaging of cigarettes and tobacco products. It is also one of the four largest print collections in the world. The quality of cigarette trademark directly determines the first impression of cigarette final consumers on cigarette products, and affects consumers' choice of cigarette products to a certain extent.

Cigarette trademark

The preference of cigarette consumers for cigarette products requires the consistency of cigarette internal quality and trademark quality. To evaluate the consistency of cigarette trademark printing quality, the printed products are usually compared with the standard samples by subjective visual inspection method or color difference instrument method. For the color difference of the reflection spectrum in the visible light range (400-700nm) that can be perceived by the human naked eye, the color difference instrument has a more accurate and rapid recognition and evaluation ability within a certain error range. For inks with very close reflection spectrum but inconsistent raw materials; Ink with high pixel, fast color conversion and beyond the calculation range of tolerance formula of color difference instrument; There are different degrees of specular reflection, and inks such as laser paper cannot be distinguished. This requires a more precise and stable color measuring instrument, spectrophotometer to measure it.

CHNSpec spectrophotometer

The following is the experiment of "quality control research experiment of cigarette packaging materials" by the technology center of a tobacco company. In the experiment, small boxes of trademark paper were selected for cigarette trademarks, and the trademark papers of cigarette brands such as Hongmei, Yunyan dachongjiu, Yunyan soft treasures and Yunyan soft Ruyi were prepared respectively. A group of parallel samples were prepared for each sample. Select the same base paper, change the type of ink, keep the original color, and make soft Ruyi trademark (New); Change the printing process conditions to make soft Ruyi lined laser paper samples and soft Ruyi lined laser paper (New) samples respectively. See Table 1 for sample number.

Table 1   summary of experimental samples for color difference analysis

The experimental instrument is cs-660 portable spectrophotometer of CHNSpec technology, and all prepared trademark papers are cut into long strips (22.5cm) with appropriate size according to the relevant provisions of GB / T 12655-2007 × 15cm), visually select 5-6 representative color blocks (dots) with uniform color on each trademark paper or laser paper. Operate cs-660 spectrophotometer to collect CIE LAB data of different color blocks (points). Each time the data is collected, the trademark paper is required to align with the center of the light hole. After collection, calculate the △ e * AB value between different samples through the software provided by the instrument. The standard light source used is D65 / A, and the color difference formula is CMC (2:1). CIELAB is the Adams color value space. In L * a * b *, the relative perceptual difference between any two colors can be used Δ E * AB indicates.

Table 2 Comparison of color difference analysis

According to the color difference analysis in Table 2, cs-660 portable spectrophotometer can be used to quickly analyze the appearance color difference of cigarette trademark paper, and has certain recognition ability for different kinds of trademarks, especially for trademark paper samples produced under different process conditions (temperature, humidity, raw materials) and trademark paper samples of different ink types. Cs-660 portable spectrophotometer technology can solve the problem of distinguishing the appearance color difference of most trademarks, and can be applied to the quality of cigarette products, especially in the process of appearance quality control, which has strong guiding and reference significance.