1. The influence of ink viscosity

济南印刷厂油墨黏度应与印刷速度相匹配，高速印刷时，油墨的黏度控制在12～15秒(3#察恩杯)之间；中速印刷时，油墨的黏度应控制在16～18秒(3#察恩杯)之间。油墨黏度过高，对印版滚筒的黏附性过强，不利于刮墨刀将版面多余的油墨刮干净，印刷品出现刀线的几率就高。印刷过程中要定时测量和控制好油墨黏度，一般隔20—30分钟测量一次。

The viscosity of ink in Jinan printing plant should match the printing speed. When printing at high speed, the viscosity of the ink should be controlled between 12 and 15 seconds (3 × chaen cup); in medium speed printing, the viscosity of ink should be controlled between 16 and 18 seconds (3 × chaen cup). The viscosity of the ink is too high, and the adhesion to the printing plate cylinder is too strong, which is not conducive to the scraping knife to clean the redundant ink in the layout, and the probability of knife line in printed matter is high. During the printing process, the ink viscosity should be measured and controlled regularly, usually every 20-30 minutes.

2．油墨干燥性的影响

2. The influence of ink dryness

油墨干燥过快，容易出现结皮现象，如果结皮在油墨循环过程中未被溶解，一旦接触到刮墨刀就会黏附在刀口或刀底，产生印刷品刀线。如果油墨循环系统采用的是敞口墨槽，更容易发生油墨结皮、结块现象。为了减少此类刀线故障的发生几率，要经常搅拌墨槽中的油墨；根据需要加入适量慢干剂；如有条件，还可加装密封盖，能够有效地控制和减少印刷品刀线故障。

If the ink dries too fast, it is easy to skin. If the crust is not dissolved in the process of ink circulation, once it contacts the doctor blade, it will adhere to the edge or the bottom of the knife, resulting in printed product knife line. If the ink circulation system is open ink tank, it is more likely to occur ink crust, caking phenomenon. In order to reduce the occurrence of such knife line failure, the ink in the ink tank should be stirred frequently; appropriate amount of slow drying agent should be added as required; if possible, a sealing cover can be added to effectively control and reduce the knife line fault of printed matter.

3．油墨细度的影响

3. The influence of ink fineness

凹印油墨主要由颜料，连结料、助剂等成分组成。如果颜料研磨不充分，颗粒较粗，且不溶于连结料和溶剂中，印刷时停留在刮墨刀口，就会导致印刷品出现细小，不规则的刀线。颜料颗粒的细度对刀线的出现频率有直接影响，例如蓝墨中所使用的颜料颗粒硬度高，即使经过充分研磨也很难达到很细的颗粒度，在印刷过程中就容易损伤刮墨刀或影响刮墨效果，印刷蓝墨时经常出现刀线故障。

Gravure ink is mainly composed of pigments, binders and additives. If the pigment is not fully grinded, the particles are coarse and insoluble in the binder and solvent, and stay at the edge of the squeegee during printing, it will lead to small and irregular knife lines. The fineness of pigment particles has a direct impact on the frequency of knife line. For example, the pigment particles used in blue ink have high hardness, and it is difficult to achieve a very fine particle size even after full grinding. In the printing process, it is easy to damage the doctor blade or affect the scraping effect. When printing blue ink, knife line failure often occurs.

4．油墨活性的影响

4. The influence of ink activity

在油墨生产过程中，一般都加入一定量的活性剂。印版滚筒镀铬后也有一定的活性，如果油墨和印版滚筒的活性太高，在印刷时，活性物质就会牢固地黏附在滚筒上，刮墨刀也很难将其刮干净，从而形成刀线。此时先对印版滚筒进行清洗，清除其表面的活性物质，同时在油墨中加入活性减缓剂消除刀线。

In the ink production process, generally add a certain amount of active agent. The plate cylinder also has a certain activity after chromium plating. If the activity of the ink and plate cylinder is too high, the active substance will adhere firmly to the cylinder during printing, and it is difficult for the scraper to clean it, thus forming a knife line. At this time, the plate cylinder is cleaned to remove the active substances on its surface, and the active retarder is added to the ink to eliminate the knife line.

5．油墨质量的影响

5. The influence of ink quality

油墨储存时间过长，溶剂平衡发生变化，引起油墨溶解力降低；或者油墨调配、使用不当，引起化学反应，都会使油墨产生沉淀。在印刷过程中，油墨中的沉淀物容易积聚在刮墨刀口引起刀线，需要更换油墨。

Ink storage time is too long, solvent balance changes, resulting in ink solubility reduction; or ink deployment, improper use, causing chemical reactions, will make ink precipitation. In the printing process, the deposit in the ink is easy to accumulate on the blade edge, causing knife line, so the ink needs to be replaced.