Printing principle of the hottest printing machine

2022-08-21
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The principle of printing press

overview

corrugated boxes used as transport packaging appeared in the United States in 1907. During the first World War, wooden transport packaging accounted for 80%, and corrugated boxes accounted for only 20%. By the Second World War, corrugated boxes had accounted for 80% and become the most important transportation packaging containers. In 2006, the contraction rate decreased. In 2006, the total value of China's packaging industry was about 350billion yuan, and paper products accounted for 59%

purpose of packaging carton

it can be used to package food, beverage, household appliances, medicine, daily use/cosmetics, electromechanical and other products

advantages of packaging carton

light weight

the weight of three-layer (single corrugated) paperboard is about 600 g/m2 based on 175/150/150g/m2 of paper, while the weight of wood board with the same 3mm thickness is about 2000 g/m2, which is more than three times that of paperboard

low cost

its raw material is base paper, which can be made of wood pulp (leftover material of wood) and straw pulp, and can be easily reused (pollution-free). (environmental protection)

easy processing

due to the flatness of the paper, it can be easily printed

convenient for storage and transportation

because cartons can be folded, they occupy very little space during storage and transportation, which is very convenient for storage and transportation, which wood packaging and metal packaging do not have

reasonable structure

the corrugated (U, V, UV) structure greatly provides the compression resistance and burst resistance of the carton

insufficient carton packaging

strength has limitations

if wood or other solid objects are not used for reinforcement, the weight of the items contained in the carton (except honeycomb paperboard) should preferably not exceed 55kg

poor moisture resistance

after absorbing water, the strength of corrugated boxes will drop sharply, or even be broken, which should be paid attention to in design and use. Adding moisture-proof agent on the surface of face paper (lining paper) (which can be added before printing, during corrugated forming, or after printing) can appropriately improve its moisture-proof property

carton production process

base paper

base paper is one of the important factors in forming the product quality of paperboard and carton, and it is the main raw material of paperboard and carton. According to the purpose, it can be divided into two categories, namely, carton board (GB) and corrugated base paper (GB)

carton board

used as face paper, lining paper or center paper of corrugated boxes. The quality grades are a, B, C and D. Among them, a, B and C are vermicelli. According to the color and surface treatment of the paper, it can be subdivided into white paper and kraft paper

corrugated base paper

used as base paper for corrugated production in corrugated boxes. Its quality grade is divided into a, B, C and D. Generally speaking, Grade A and B are called high-strength corrugated base paper, and grade C and D are medium strength corrugated base paper. According to the manufacturer, it can be divided into domestic paper and imported paper, and imported paper can be subdivided into American card, Russian card, etc

main technical indicators:

quantitative (gram weight):

weight of base paper per square meter (g/m2). Generally speaking, the current gram weight ranges from 100 g/m2 to 400 g/m2

tightness:

is equivalent to an index of density, which refers to the weight of base paper per cubic decimeter (g/cm3). Bursting index (kpa.m2/g) and ring pressure index (n.m/g), which reflect the physical properties of base paper

shape of corrugation

the basic shape of corrugation is U-shaped and V-shaped. The U-shaped corrugation peak is close to circular, and the v] shaped corrugation peak is close to sharp. The characteristics of U-shaped corrugation are:

a) soft and elastic. As long as the deformation does not exceed the elastic range, the U-shaped corrugation can quickly return to its original shape after loosening

b) due to the slow wear of the corrugating roller, the thickness of the corrugated board is the same

c) the U-shaped corrugated is relatively smooth and will not cut the corrugated core paper at the ridge peak. Therefore, the consumption of corrugated base paper and adhesive can be relatively increased, but it is not economical

v-shaped corrugation features:

a) V-shaped corrugation is relatively hard and has high strength, but once the deformation exceeds the elastic range, the corrugation will be crushed and completely lose its restorability

b) although the use of core paper and adhesive in V-shaped corrugated is small, the corrugating roller is easy to wear, the service life is short, and the thickness of corrugated board is unstable, and the core paper is easy to be cut at the peak of corrugation

China stipulates (recommends) that the corrugated shape is between U-shape and V-shape, which is called UV shape. Its elasticity and processing performance are better than V-shape, and its flat pressing strength and materials are better than U-shape. UV corrugated board has the advantages of U-shaped and V-shaped corrugated board and is widely used

corrugation type of corrugated paperboard

corrugation height and corrugation number per 300mm length are called corrugation type of corrugated paperboard. The corrugation type is actually the relevant regulations on the corrugation size. The commonly used corrugated types are: a tile (type), B tile (type), C tile (type), e tile (type). With the development of corrugated roller manufacturing technology and packaging industry, some smaller corrugated types such as F, G, N, O also appear

the commonly used corrugated type of transportation packaging is A-type and B-type. The height of type a corrugated is the largest, which is soft, elastic and has good cushioning performance. The flat pressing strength of B-type is high, which is suitable for products with hard packaging. At the same time, because the corrugated spacing is small, and the paper is relatively flat, the printing effect is better. C tile is between a tile and B tile, and it is rarely used alone at present. However, under appropriate circumstances, BC corrugated can be used to replace AB corrugated. Below e-tile, it is called micro corrugated, which is designed to replace thick cardboard

number of layers of corrugated paperboard

the number of layers of base paper on the cross section of corrugated paperboard is its most important structural feature. In terms of the number of layers of corrugated core paper, single corrugated board, double corrugated board and three corrugated board are usually used for transportation and packaging. Single corrugated board has three layers, including face paper (outside), inner paper (inside) and corrugated core paper. It is also called three-layer board in custom. Three layer paperboard accounts for the largest proportion in corrugated paperboard, which is mainly used to package light products, such as commonly used food and beverages

there are five layers of face paper, intermediate pad paper and corrugated core paper of double corrugated board, which is also called five layer board in custom, and is mainly used to pack fragile products with large weight. Double corrugated board is usually composed of A-type and B-type. Generally, A-type corrugated board is placed on the inner side of the carton for cushioning, and B-type corrugated board is placed on the outer side to make the printing on the surface of the carton more beautiful. There are seven layers of face paper, intermediate pad paper and corrugated core paper of three corrugated board, so it is also called seven layer board, which is mainly used to pack ultra heavy products

a) single corrugated board (three ply board) b) double corrugated board (five ply board) C) three corrugated board (seven ply board)

box type of corrugated box

most of the box type of corrugated box is O2 type (box type is international general) slotted box. Among them, the 0201 slotted flat box is the most commonly used transportation packaging box, which is characterized by the upper and lower swing covers connected with the box surface, and the box bottom and cover are formed after being bent inward. Generally, a whole board is cut, (printed) slotted and pressed into a box blank (a few are assembled by two or four pieces of cardboard, which is customarily called a two page box or a four page box)

structure of corrugated box

corrugated box is based on box blank and becomes a box structure through combination, sealing and binding

production of corrugated cartons

corrugated paperboard

the current corrugated paperboard is generally made from corrugated production lines. In some small production plants, for some paperboards with low quality requirements, there are also single-sided corrugated machines that produce one flat and one tile, and then cover them to form a single corrugated paperboard. The paperboard produced by the corrugated board production line after longitudinal indentation tangent and transverse cutting generally has the basic characteristics of the box blank: the length and width of the box blank and the longitudinal pressing line

structure of corrugated production line

corrugated production line can be divided into medium and low speed (below 150m/min) and medium and high speed (above 150m/min) according to its maximum production speed. Generally, a corrugated production line is composed of the following single machines and systems:

A) base paper support

is used to support the base paper so that it can be produced at a certain speed. At present, hydraulic shaftless mode is generally adopted. The advanced tile line can be equipped with an automatic paper feeder on the base paper support to ensure the quality and efficiency when changing paper

b) preheater

preheat the base paper before entering the corrugating roller to make it easy to form and bond

c) single sided machine

corrugation takes the average value as the hardness value of the test piece. One of the heart parts of the production line is the corrugation forming machine, and the main part is the corrugation roller. The quality of the corrugating roller, the paper feeding method (paper guide, vacuum adsorption paper guide, positive pressure system paper guide) and the overall accuracy of the single-sided machine will determine the quality of one flat and one tile produced by the single-sided machine. At present, more advanced equipment can be equipped with tile roll quick change system to improve work efficiency. The corrugating roller combines the upper and lower corrugating rollers to press the corrugated raw paper into corrugated paper. The matching pressure (GAP), parallelism and appropriate medium height of the corrugating roller are important technical indicators when the corrugating roller works

transfer the base paper from the outside of the production site to the in plant transportation equipment at the base paper support

e) conveying bridge

also known as overpass. Its function is to match the single-sided paperboard produced by each single-sided machine and preliminarily solidify the single-sided paperboard

f) multiple preheaters (double, triple, etc.)

preheat the single-sided paperboard output from the single machine, so as to facilitate the gluing and bonding of the flexible and transparent high impact pneumatic pipe below, and maintain the proper dryness of the paperboard

g) double sided glue applicator

glue one side of the corrugation and the other side of the corrugation peak, so that the corrugation can be bonded. The main components are upper rubber roller and equalizing roller

h) bonding dryer

the pasted paperboard needs to be cured at a certain temperature, pressure and time. At present, the ballasting system mainly has the following three ways: gravity roller ballasting, pressure plate ballasting, and air bag ballasting. In addition to the ballast mode, another main component of the system is the conveyor belt. The quality of the conveyor belt (thermal conductivity, air permeability, etc.) also has a great impact on the quality of paperboard, mainly domestic (such as Shenyang Xingzhong) and imported conveyor belts

i) longitudinal cutting indentation machine

it is called longitudinal with the vertical direction of corrugated. In the longitudinal direction, the paperboard specification and the crimping groove at the fold can be realized on the longitudinal cutting and indentation machine. The longitudinal cutting indentation machine generally adopts the form of single knife (thin knife), and its tool adjustment methods can be divided into manual adjustment and full computer adjustment

j) separation bracket

bracket when slitting and separating paper

k) crosscutting machine

there are two types: mechanical type and computer type. The mechanical type is an early model, and the cross cutting size needs to be adjusted manually. However, the cross cutting size of the fully computer-controlled cross cutting machine is directly set in the computer, and its size error is also small

l) conveyor

the paperboard that has been cut longitudinally and cut transversely into a certain specification (l*b) is transported to the facility of the rear stacker

m) stacker

the cut cardboard is stacked according to the specified requirements

n) main drive

main drive system including main motor

o) paper edge crusher

collect the longitudinally cut corner waste and crush it for disposal

p) paste machine

the bonding between corrugated and tissue paper requires adhesives. The paste making machine is the equipment for making adhesives. At present, corn starch is mostly used as the main body of adhesives, supplemented by additives

q) steam heating system

provide a heating system to increase the temperature of the paperboard. It can be electric heating, oil heating or coal-fired boiler

r) compressed air system

there are many pneumatic actuators in the whole production line

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