Top 10 Common Problems in Printing and Solutions

Today, let’s take a look at the top ten common problems in the printing of corporate video brochures and how to deal with them. We provide solutions for video brochures for all types of businesses. Hope it can help everyone.

1. Ink

1) Concentration: The ink with high concentration uses less ink in printing, and the ink color is better; the ink with small concentration uses more ink in printing, and the ink color is light;

2) Fineness: that is, the size of the ink particles, the ink fineness is high, the ink concentration is large, the dots of the printed matter are clear, full and powerful; the ink fineness is low, the dots of the printed matter are prone to hairy, and the printing plate has a low print durability;

3) Viscosity, high viscosity, easy to cause uneven ink transfer, dot brushing and pattern printing, etc.; low viscosity, easy to cause ink emulsification and layout fouling;

4) Fluidity: If the fluidity is large, the level of the image and text will be unclear, and the ink color will not be full; if the fluidity is small, the spread of the ink will not be smooth and uneven, and it will easily cause the front dark and the back light or the front light on the same printing surface. deep phenomenon;

5) Lightfastness: inks with good lightfastness can print products with brilliant color, full and strong graphic dots, full of three-dimensional effect, and can be stored for a long time; inks with poor lightfastness, the color of printed products is easy to become lighter and darker;

6) Water resistance, acid resistance and alkali resistance: For offset printing inks, special attention should be paid to inks with strong water resistance, acid resistance, alkali resistance, water resistance, acid resistance and alkali resistance. The printed products have bright colors, distinct layers and clear dots. ; Water resistance, acid resistance, alkali resistance, poor ink, the printed product is dark and weak, the level is unclear, and the dots are not clean.

2. Fountain water

The PH of the dampening water is generally between 3.8-4.6. In actual production, it should be adjusted according to the specific conditions of the printing conditions. If the acidity of the dampening water is too strong, the trachoma in the blank part of the layout and the lipophilic foundation of the pictures and texts will be affected. The corrosion will increase, which is easy to cause the phenomenon of flower pattern, which will reduce the printing durability of the printing plate; at the same time, the ink is easy to emulsify, the ink roller will deink, and the printed matter will be dull and dull. If the acidity of the dampening water is too weak, the hydrophilic and oil-repellent performance of the blank part of the printing plate will be weakened, the layout will be easily dirty and the printing will be caused by the expansion of the dots of the printed matter. The layout is easy to get dirty)

3. Color sequence

Color sequence refers to the overprinting sequence of each color printing plate in multi-color printing. Different color sequences will produce various printing effects. It is very important to arrange the color sequence reasonably. But the color sequence is not absolute. The general arrangement of color sequence is: single-color machine: yellow→magenta→cyan→black two-color machine: black→yellow, magenta→cyan (landscape painting) or cyan→red (character); When there are gold, silver, and full-page solid printing, generally gold, silver, and full-page solid printing are required first, and then four-color ink is applied after the ink is dry.

4. batch printing

1) Check whether the specifications of the four-color film are consistent (whether the four films are complete);

2) Check the completeness of the pictures and texts against the proofs;

3) Stabilize the moisture and ink volume to achieve the ink level, so as to ensure the consistency of the ink color of the same batch of prints;

4) Try to do as little downtime as possible or clean the blanket after downtime (you can put some pasted paper)

5. Formal printing

During formal printing, the operator should concentrate on:

(1) Look: look at the operation of the machine, look at the ink color, registration and dot quality of the proofs;

(2) Listen: listen to whether the sound of the machine is abnormal, and listen to whether there is any noise in the vibration sensitive area of ​​the machine;

(3) Touch: touch the parts of the machine that are easy to heat up due to wear and tear to see if there is a significant temperature change;

(4) Smell: smell whether there are electrical burnt and other abnormal smells (pay more attention to the power cord of the UV machine when printing with UV ink);

(5) Inspection: Check the printed products and whether there is any abnormality in the machine, find any problems, and eliminate them in time.

6. how to identify the size of water

To identify the difference of moisture, we should first look at the moisture of the layout. This depends on the operator’s experience. Generally speaking, if the moisture content is large, the amount of reflected light on the layout is strong, and the side view is brighter; on the contrary, the amount of reflected light on the layout is weak, and the side view is darker; if the moisture content is too large, it can also be observed from the following points:

(1) Use cardboard to shovel ink on the ink roller, and there will be small water droplets on the cardboard;

(2) There are small water droplets on the water string roller, and deinking phenomenon or water droplets in the ink roller group;

(3) After turning off the water or shutting down for a long time, the water on the layout has not dried up;

(4) The dots of the imprint are empty, and the ink color is dull and dull;

(5) There are water shadows or water droplets at the end of the rubber roller.

7. control the water balance

Ink and water are not absolutely incompatible. In the actual printing process, the ink and water will be fused together through the extrusion of the rubber roller and the rubber roller to emulsify the ink. There are two emulsification states of ink: when water is large and ink is small, “oil-in-water” is formed; when water is small and ink is large, “water-in-oil” is formed. In the process of offset printing, the mastery of ink balance is closely related to the normal transfer of imprint, the depth of ink color, the accuracy of color registration, and the drying and stickiness of printed matter. Generally speaking, if the water is large, the ink will be emulsified and the ink color will be light; if the water is small, the ink will adhere to the blank part of the layout, resulting in smudges. Therefore, controlling the balance of ink and water in offset printing is the key to printing.

8. control ink balance

To control the balance of ink and wash, it is generally necessary to master the principle of less water and thick ink. Less water, refers to the premise that the blank part of the layout is not sticky; thick ink, refers to the appropriate increase in the amount of ink on the basis of less water. In the printing process, the most taboo point is that the water is large and the ink is large. When considering the amount of water, it should be based on the size and distribution of the layout image and text, the thickness of the imprinted ink layer, the properties of the printing paper, the performance of the ink, the running speed of the machine, the temperature and humidity of the workshop, the pH value of the fountain solution and the amount of water added to the ink. auxiliaries, etc.

9. Clean the blanket, and the ink roller must be cleaned when changing colors

After a period of printing, paper wool, paper powder, ink skin and

Other dirt reduces the quality of the printed matter, so the blanket should be cleaned in time, especially for paper with low printing strength, the accumulation of paper wool and paper powder is more serious, so it should be cleaned more often. If the ink roller group is not cleaned when changing colors, it will affect the purity of the new ink color, especially when changing from dark ink to light ink. For example, when changing from black ink to yellow ink, if the black ink is not cleaned, the yellow ink will turn black, which will affect the quality of the brush. Therefore, the ink roller set must be cleaned when changing colors.

10. The main factors of inaccurate overprinting

(1) Printing press

a. The locking screw of the heaven and earth adjustment plate is not fixed, or whether the M5 inner hexagon screw on the paper feeding rocker arm has been fixed tightly;

b. Whether the copper sleeve of the paper pusher is worn;

c. The paper feeding teeth are worn;

d. The printing pressure is too small;

e. Gear wear;

f. The blanket is too loose and not tied tightly

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