Acceptance and storage requirements of the hottest

Paper packaging requirements for the acceptance and storage of flat paper

paper is the main substrate of printing, and the quality of paper affects the quality of printing. Therefore, it is the premise for printing enterprises to grasp the quality of the purchased paper. The gear drives the pressing shaft to rotate the parts at the same time. It is of great significance for printing enterprises to strengthen and pay attention to the acceptance and storage of paper quality. This article talks about some views on the acceptance and storage of flat paper

1 acceptance of flat paper

1) acceptance of paper outer packaging

at present, flat paper packaging mainly adopts two basic forms: wood plywood packaging and wooden box packaging. Generally, the appearance of qualified flat paper is packed with more than two layers of packaging paper, plus wood packaging, which is bound tightly with iron strips. The packaging paper used mainly includes wax paper, asphalt paper, kraft paper, snake skin paper, etc. The words "moisture proof", "do not throw" and other words are marked on the wooden plywood or wooden box, and some also indicate the thread direction of the paper. The quality certificate of the product shall also be pasted on the wooden plywood or wooden box, and the product name, specification, order weight, order number of each piece, paper grade, executive standard, production date, manufacturer name, etc. shall be indicated. The outer package shall be intact without deformation or damage. If the outer package is seriously damaged and the paper is exposed outside the package, you should not hesitate to reject it or take other measures to avoid unnecessary losses. The acceptance of paper packaging is a basic acceptance, which must be strictly grasped

2) appearance acceptance after removing the outer package

remove 1. After understanding the outer package of the next bar paper, first check whether there is a quality inspection sheet, and then check the paper phase and color

the basic feature of normal paper phase is good flatness, that is, the paper is correspondingly flat with flat end face. For a piece of paper, it is relatively difficult to judge whether the paper phase is normal, unless the paper has been seriously deformed. The usual method is to untie the paper bag and stack it 1m high to see whether the paper phase is normal. When the paper phase is abnormal, it shows a variety of shapes, including wavy and dished shapes. Other shapes such as mountain shape, valley shape, angle warping shape, bag shape, inclined shape, valley shape, curl shape, saddle shape, etc. There are many reasons for these bad paper phases, which can be summarized as follows: ① the moisture content of the whole paper is uneven, resulting in uneven local shrinkage; ② Uneven thickness of paper formed in the process of papermaking; ③ The expansion and contraction of the front and back sides of the paper are inconsistent, especially for single-sided coated paper. In addition, it can be seen from the side of the stack whether the color of the paper is uniform. In any case, the paper supplied in the same batch must have consistent whiteness, uniform hue and small color difference. Otherwise, after the printed matter is bound into a volume, there will be obvious color stratification in the head, foot, incision and other parts

3) inspection of single sheet paper

take a sheet of paper from the stack at will, and check whether it has appearance paper disease and its uniformity. Touch the surface of the paper by hand or look at the paper horizontally, and check the smoothness and cleanliness of the paper surface. 2. Set the number of experiments and automatically stop the machine. Generally speaking, the surface of the paper should be flat without marks or pimples. At the same time, the surface of the paper should not have bright and dark spots with different reflections, or dust inconsistent with the color of the paper. Raise the paper to observe in the light and check the uniformity of the paper. The paper should not have light transmission or transparent points of different shades and degrees when observing against the light. If a large area of uneven cloud like spots appear on the paper, it means that the uniformity of the paper is very poor, which will seriously affect the quality of the print

4) inspection of taking 4 ~ 5 sheets of paper

flat paper is sometimes cut and stacked by multiple reels at the same time. Due to the subtle differences in the papermaking process of different reels, the properties of adjacent sheets of paper in the same stack are different. If one of them is mixed with an unqualified web, then a circular abnormal phenomenon will occur, and printing faults will occur at a certain interval during printing. Therefore, it is necessary for this machine to take several sheets of paper continuously from the paper stack for comparison and inspection after the failure of the protective power supply to check whether there is such a difference between adjacent papers. Although this kind of situation is relatively rare, sometimes this kind of observation and analysis is particularly important. We must pay attention to the accumulation of experience in this regard

5) acceptance of paper size

the paper size shall be measured by a steel tape with a length of 2M and an accuracy of 1mm according to the national standard. During measurement, three samples shall be randomly taken from the same package, and the measurement results shall be expressed in all measured values, accurate to 1mm. The allowable error of paper length and size is ± 3mm. The deflection of the paper will cause insufficient or excessive paper size, resulting in the angle between the long side and the short side of the paper not at right angles. Therefore, in addition to measuring the length and size of the paper, the deflection of the paper should also be measured. The allowable deviation of paper deflection is 3 ~ 5mm

6) check whether the quantity of paper is consistent with that marked by the manufacturer

cut 5 sheets of 200 with a paper cutter × The 250mm paper sample is weighed on a balance with high sensitivity, and then the measured mass is divided by the area of the paper. The obtained value is the quantitative value of the paper. The measured result shall be very close to the quantity marked on the product certificate. The quantity can fluctuate within the range allowed by the national standard, but cannot exceed this range. (to be continued)