The main contents of the Quality Standards for Gravure Prints (GB7707-87) are as follows:
This standard applies to plastic film and cellophane decoration prints produced by gravure printing processes.
(1) Technical requirements. 1 appearance. The finished product is clean and tidy, with no obvious stains, incompletes, or cuts. The printing of the text is clear and complete. The word below No. 5 does not miss the word. The edges of the blots are bright and clean, and the texture is clear and uniform, with no obvious distortion or incompleteness. 2 Overprint errors should conform to Table 1:
Imprinting area limit deviation field printing net print main parts ≤ 0.5 ≤ 0.3 Minor parts ≤ 0.8 ≤ 0.6
Field printing requirements should be in accordance with Table 2: Indicator Name Unit Symbol Indicator Value Color Density Deviation - Ds ≤ 0.06 Same batch color difference CIEL*a*b* △EL*> 50.00L* ≤ 50.00 ≤ 6.00 ≤ 5.00 The gloss of the ink layer % Ds (60) ≥ 35 ink layer combination of fastness% - ≥ 95
(2) Test methods. 1 test requirements. The test chamber temperature is 23±2°C. Relative humidity 50% ± 5%. Samples were pretreated and placed in a non-ultraviolet radiation environment for not less than 8 hours. Light source: D65 standard light source with color temperature of 5500 ~ 6500K, and the light source is about 800mm away from the sample table top. 2 appearance. The sample was placed under the specified light source, and the observer's eyes were visually identified by being about 800 mm from the visual site. 3 overprint error. The light source is the same as 1. Instrument: 20x scale microscope with an accuracy of 0.01mm. Test procedure: Under the requirement of the light source, the overprint error between the main and secondary parts of the test specimen is measured. Three points are measured and the average value is taken as the overprint error of the main part and the minor part. 4 deviation of the same color density. Instruments: Reflective color densitometers with color filters and infrared filters with radon 58, 47, and 25, with an accuracy of less than or equal to ±0.02D. Color filter use. The infrared color filter is used for black, white, or gray. Measured colors for the three primary colors according to Table 3 use color filters. If the measured color is made up of two or more primary colors, the color filters listed in Table 3 shall be used separately. Measured color selected color filter name code color magenta Redden 58 C Green Yellow Redden 47 B Blue Blue Redden 25 R Red
Test procedure: The background was white when tested. Select the color filter according to the color to be measured. Use a standard whiteboard to calibrate the instrument so that the color density value is equal to the value specified on the whiteboard, accurate to ±0.01D, once for each filter, and calibrated once. For finished products with a web size of 129mm x 184mm or less, measure 1 in the four corners of the same sample and in the middle of the same color; if the finished web is larger than 129mm x 184mm (32), measure 5 points evenly on the same sample. 5 same batch of color difference. Instrument: The use of integrating sphere type colorimetric color difference meter, pointed in line with the provisions of Chapter 3 of GB3979-83 "measurement method of object color" standard lighting body is D65, colorimetry measurement field of view is 10 ° adopt "CIE 1964 supplementary standard color Observer data. The measurement area is generally a round hole with a diameter of φ25 mm. If the measured area is small, a small-area observation hole is allowed. Its area must not be less than 25 mm2. The test procedure measures the L*a*b* value of the CIEL*a*b* uniform color space on the basis of the print sample, and then measures the color difference between the sample and the same part of the same color. 6 ink layer gloss. Instrument: The gloss meter should include a light source and a lens that can project a parallel or slightly convergent beam onto the surface to be measured. The gloss meter also includes a receiver, the receiver with a lens field grating and to receive the desired The light path of the reflective cone of light is shown in Figure 144. Geometry: The incident ray is 60°±0.5° (θ) from the vertical line of the surface being measured. The axis of the receiver should coincide with the image of the incident light axis. If a flat polished black glass is placed on the test weight position, the image of the light source should fall on the center point of the receiver field of view raster. The width of the test panel light point should not be less than 10 mm. The angle (θ') between the axis of the receiver ray and the perpendicular should be equal to the corresponding incident angle of the incident light. Light source: Use CIE standard C light source or D65 light source. Instrument calibration: The working standard model uses tiles, enamel, matt glass, and other turbulent materials, the surface must be smooth. A gloss meter must be equipped with a standard sample and a working standard sample. The sample must be calibrated regularly and its operating characteristics should be uniform and stable. Glossmeters are calibrated at the beginning of each test period and at intervals during the test to ensure that the instrument response is essentially the same. When the approval is made, the instrument is first zero-adjusted, and then it is allowed to correctly display the glossiness of a standard sample with a higher gloss. Then put a working standard board to read the lower standard gloss. The difference between the reading and the value specified in the standard must not exceed 1 gloss unit range. Test procedure: 1 The sample must be flat and wrinkle-free. 2 Measure the surface of different color layers of the sample. The color area is measured within 100cm2 three points, the color area is greater than 100cm2 measured five points. 3 Double the test point when the gloss difference of each color measurement of each sample is greater than 5 units. Test result: The average value of glossiness of the sample is calculated as the glossiness of the sample. test results. Cover the exposed part with a translucent millimeters wide paper with a width of 20mm. The number of cells occupied by the ink layer and the number of cells occupied by the peeled ink layer are counted. Calculated as follows:
A1
Ink adhesion combined fastness=——————×100%
A1+A2
In the formula: A1—the number of cells in the ink layer;
A2—The number of cells in the removed ink layer.
(3) Inspection rules. 1 A group of unit products that have the same production conditions, the same variety, and delivery at the same time are in one batch. 2 The number of samples in each batch is generally 5 pieces. 3 Non-conformity judgment: Each product shall be tested according to the test method to determine the technical indicators required by the product. If one or more technical specifications do not meet the requirements, the product is a non-conforming product. 4 Judgment of unqualified batches: Each batch of product is sampled according to the sampling table or stratified sampling method. There are one or more unqualified items in each batch of products, which should be doubled. If there is still one or more non-conforming products, the batch is a non-conforming batch.
(4) signs, packaging, transportation and storage. 1 mark: Each package should be checked on the head of a qualified label, indicate the user unit, product name, specifications, quantity, manufacturer name, date of manufacture and inspector code. 2 Packaging: According to user requirements or according to the volume or quantity of the product with a more solid packaging paper sub-bundling. 3 Transportation: It is not allowed to throw, twist or step in transportation. Pay attention to moisture proof, anti-leaking, anti-exposure, anti-hot grilling, anti-pressure and anti-corrosion gas and liquid. 4 Storage: Storage environment requires moisture, sun, oil, mildew, anti-corrosion gas, can not be heavy pressure, the storage period is generally six months.