Causes and Countermeasures of the most popular off

2022-07-27
  • Detail

Causes and Countermeasures for the failure of offset rotary ink (II)

circular white spot:

phenomenon:

there is a round core in the print surrounding a small dot of ink

cause:

1 impurities in the ink stick to the plate

2 the paper powder falls off and sticks to the plate

3 dust particles or other substances on the printing press

countermeasures from the analysis of fault probability:

1 wash the plate to remove impurities, and replace the new ink without impurities

1 the customer can put forward specific product requirements for Nangang in addition to removing impurities, and replace the paper that can not be predicted is the paper with paper powder

3 wash the plate to remove impurities

plate stacking:

phenomenon:

ink or ink mixture is accumulated on the printing plate and image blanket, and local ink is shallow or scratchy in the graphic area of the printed product

cause:

1 poor fluidity of ink after emulsification and poor transfer

2 paper powder or paper wool is mixed with ink and piled up on the layout

countermeasures:

1 replace the ink with good water resistance, or add water-resistant additives

2 replace the paper with less paper powder

the non graphic area of the printing plate is sticky:

phenomenon:

ink can be seen in the non graphic area on the printing plate

cause:

1 the ink has poor water resistance. After emulsification, it sticks to the page and is hydrophilic

2 the surface tension of the fountain solution is large, and the non graphic areas of the version are difficult to be stained with ink

3 the ink roller and plate pressure are too high

Better improve the satisfaction of new and old customers

countermeasures:

1 replace the ink with good water resistance

2 increased IPA content

3 adjust the ink roller and layout pressure

version loss:

phenomenon:

poor inking in the image and text area of the printing version, reduced print concentration or uneven images and text

cause:

1 the printing plate has poor greasiness

2 the paper powder falling off the surface of the paper wears the layout

3 the image and text film of the printing plate is worn off due to excessive pressure

4 too much pH solution in the fountain solution causes the printing plate to corrode and the pictures and texts to fall off

countermeasures:

1 replace the new version

2 change the paper with better quality and use the ink with lower viscosity

3 adjust the imprint to reduce wear

4 pay attention to the adjustment of fountain solution and add pH solution in a reasonable proportion

· ink sticking on water roller:

phenomenon:

there is ink on the water transfer roller of the printing machine

cause:

1 ink emulsification with poor water resistance

2 the water roller and plate pressure are abnormal

countermeasures:

1 replace the ink with good water resistance

2 adjust the water roller pressure

· poor overprint:

phenomenon:

poor overprint or poor overprint of rear color sequence ink

cause:

1 the rear color sequence ink is more viscous than the front package sequence ink, pulling the previous color ink away

2 the back color sequence printing press is too large, and the front color ink is pulled off

countermeasures:

1 change the color sequence or reduce the viscosity of the ink after the color sequence

2 reduce the printing pressure of the adjusted color sequence printing machine

(to be continued)

Copyright © 2011 JIN SHI