Tactile inspection method for appearance quality of paper sheet

The appearance quality of a paper sheet refers to the quality of a certain area of ​​a single sheet or paper tape that can be felt by one's touch.

The method of checking the appearance quality of web paper is generally to cut 10 layers of the outer circumference of the reel, remove the outermost 5 layers, and use 5 layers as the pattern to check the quality of the web (each batch should generally take 2-3 Pieces). The appearance quality of the flat paper is relatively easy to check. Generally, all the papers in the same batch are opened according to the standard sampling method, and two orders are taken from each piece to check the appearance quality. Through the inspection, the main advantages and disadvantages of the appearance of the paper were ascertained, and the missing rate of the paper and the existence of paper diseases were found out. The specific inspection methods are as follows:

First, reflected light flat vision inspection

The paper is laid flat on the table or on the table, and the color, whiteness, flatness, and smoothness of the paper sheet are observed with the naked eye at a distance of about 30 cm from the surface of the paper. Pay attention to check the paper for dust, spots, holes, holes, pleats, wrinkles, broken sheets, cracks, folded corners, dirty spots, seersuckers, pulp blocks, and other hard blocks. When looking at the paper, the eyes are looking at the surface of the paper, and it is generally conducted under ordinary indoor light. It is not appropriate to use strong light or direct sunlight. If necessary, you can also use the general magnifying glass to observe.

Second, light perspective inspection

Look at the paper against the light source (or on the glass with the reflector lamp), let the light through the paper, and observe the quality of the paper with the naked eye. Check the uniformity and opacity of the paper fibrous tissue and check the quality of the paper. Check the degree of uniformity and opacity of the fibrous tissue of the paper, and check whether the paper has “cloudy flowers”, clear spots, dirty spots, holes, and streaks of uneven light transmission.

Third, obliquely check

Some appearance paper diseases, such as glossy or dull scratches on paper, felt marks, roller shadows, etc., are not easy to find with a flat-view inspection method, and must be seen with oblique inspection. Oblique-view inspection is to raise or lower one side of the paper with both hands, and look at the paper from different angles to see if the appearance quality of the paper is flawed or inadequate. If there are papers in the process of copying, due to the vacuum level of the vacuum roll or the pressure on the roll-up roll, the regular arrangement of holes on the roll-up roll will be reversed on the surface of the paper. The shadow of this hole is not obvious enough, and the head-up inspection and fluoroscopic examination are not easy to find, and can only be found when checking obliquely. Another example is to check if the paper surface is fluffed. Generally, first rub the paper surface with your hand, and then raise one side of the paper. Look at the eyes closer to the light. If the paper is fluffy, you can see many small fibers standing on the paper surface.

Fourth, hand touch inspection

The hand touch examination is reflected by the feeling of touch of the sensory organs. Hand touch inspection can find the thickness of the paper is not the same problem, but also experienced by hand to grasp the degree of high paper on the low side. The hand touch inspection can also determine whether the paper is trapped inside the sheet of grass, fiber bundles and fine sand, etc., to find hidden paper disease. Some of the small pulps and small white sands on the surface of the paper, because they have the same color as the paper surface, are not easily visible to the naked eye, but can be felt by hand. In addition, if the paper is rubbed or shaken by hand, and if the paper is rubbed or shaken, whether or not the paper is cracked can be judged initially.

V. Listening check

The audition test is to shake or rub the paper by hand, and use the ear to listen to the sound of the paper to determine certain properties of the paper. The toughness of paper is often referred to as the "body bone" of paper. When the “bone” paper is used to pinch the paper up and down with two hands, the sound produced by the paper is crisp, and the sound of paper with a “bone” is weaker. The stronger the "bone" is, the stronger the paper sound is, and it is not easy to pull off under tension. The sound of paper made of different materials is also different. Generally, wood pulp paper is relatively crisp, grass pulp paper is more turbid, and cotton pulp paper is softer. The sound of the paper produced from the same raw materials with different pulping methods is different. Generally, the paper made from Kraft Kraft Pulp Kraft is a little louder.