1.銅版紙的外表強度
1. Appearance Strength of Copper Plate Paper
銅版紙的外表強度是指銅版紙外表涂料粒子之間以及涂層與原紙之間的分離強度,它是銅版紙的一項重要性能指標,通常用拉毛速度表示。銅版紙的外表強度低時,在印刷過程中易產生掉毛、掉粉現象。隨著印刷的停止,堆積在印版上的紙毛、紙粉會越來越多,后招致糊版而影響印刷質量及印刷操作。所以進步銅版紙的外表強度,對保證良好的印刷效果十分必要。
The surface strength of coated paper refers to the separation strength between coatings particles and coatings and base paper. It is an important performance index of coated paper, which is usually expressed by the drawing speed. When the surface strength of copperplate paper is low, it is easy to produce wool and powder dropping in the printing process. With the stop of printing, more and more paper wool and powder will accumulate on the plate, which will eventually lead to lithography and affect the printing quality and operation. Therefore, it is necessary to improve the appearance strength of copperplate paper to ensure good printing effect.
2.銅版紙的水分及耐溫性
2. Moisture and Temperature Resistance of Copper Plate Paper
銅版紙的水分是指銅版紙中所含水分的重量占該銅版紙重量的百分比。隨著社會的開展和進步,印刷業也有了突飛猛進的開展。商業輪轉印刷機的呈現,對印刷用銅版紙在耐溫性和水分含量方面都提出了新的請求。假如水分不當,耐溫性差,則銅版紙在印刷中的鼓泡現象會成為輪轉印刷中一個較為嚴重而較普遍存在的問題。
The moisture content of the copperplate paper refers to the percentage of the moisture content in the copperplate paper to the weight of the copperplate paper. With the development and progress of society, the printing industry has also developed by leaps and bounds. The appearance of commercial rotary printing presses has put forward new requirements for the temperature resistance and moisture content of printed copperplate paper. If the moisture content is inappropriate and the temperature resistance is poor, the blistering phenomenon of copper plate paper in printing will become a more serious and common problem in rotary printing.
由于輪轉印刷機具有高速印刷的特性,普通每小時達4萬~5萬張(而普通單張紙印刷速度快還不到2萬張/小時),在印刷枯燥后即停止直接折頁,在如此高的速度下,為了避免油墨不干、反面粘臟等印刷異常的產生,就需求印刷油墨枯燥疾速,而使油墨快速枯燥有效的辦法就是高溫加熱,所以在輪轉印刷機的構造中有一個烘箱,對印刷后的銅版紙停止加熱,使油墨可以快速枯燥。
Because of the high-speed printing characteristics of rotary printers, 40,000 to 50,000 sheets per hour are common (and the fastest speed of ordinary sheet paper printing is less than 20,000 sheets per hour). When printing is dull, direct folding is stopped. At such a high speed, in order to avoid printing abnormalities such as non-drying ink and negative stickiness, printing is required. Brush ink is dry and fast, and the most effective way to make ink fast and dry is high temperature heating, so in the construction of rotary printing machine, there is an oven to stop heating the printed copperplate paper, so that the ink can be fast and dry.
銅版紙中定量的水分在高溫烘干(烘干溫度普通在140℃左右)的狀況下變成水蒸氣向外釋放,由于銅版紙單面或雙面都有涂料層,且涂層中由于黏合劑及其交聯劑的作用,固然防止在印刷過程中發作掉毛、掉粉現象,但對印刷油墨枯燥過程中水蒸氣的向外釋放不利;假如在紙張雙面同一位置又正好是滿版印刷,且油墨量很大時,由于油墨將紙面完整掩蓋,更進一步招致水蒸氣無法向外釋出,就會產生鼓泡現象。
Quantitative moisture in copperplate paper is released into water vapor when it is dried at high temperature (usually about 140 C). Because there are coating layers on one or both sides of copperplate paper, and because of the effect of binder and crosslinking agent in the coating, it can prevent hair and powder from falling off in the printing process, but it can be used for printing. In the process of ink drying, water vapor is unfavorable to the outward release; if the same position on both sides of the paper happens to be full-page printing, and the amount of ink is very large, because the ink will completely cover the paper surface, further cause water vapor can not be released out, it will produce bubbling phenomenon.
為了防止印刷中的起泡現象,選擇和運用銅版紙時應留意以下3點:
In order to prevent blistering in printing, the following three points should be paid attention to when choosing and using copperplate paper:
(1)選擇耐溫性能好的銅版紙。
(1) Choose copper plate paper with good heat resistance.
(2)選擇含水量在6%~8%之間的銅版紙。銅版紙含水量過高,則在短時間內不能使具有涂層和油墨的印刷品中的水蒸氣快速向外釋放,從而形成鼓泡產生;含水量過低,則紙張容易產生靜電現象,并且趨于脆硬,不利于印刷;含水量不平均則會構成緊邊、荷葉邊、卷曲等。
(2) Copper plate paper with moisture content between 6% and 8% was selected. If the moisture content of copperplate paper is too high, it will not release the water vapor in the printed matter with coating and ink quickly in a short time, thus forming bubbles; if the moisture content is too low, the paper will easily produce static electricity, and tend to be brittle and hard, which is not conducive to printing; if the moisture content is not equal, it will form tight edges, lotus edges and rolls. Song and so on.
(3)將銅版紙印刷車間溫度控制在18~25℃,相對濕度堅持在50%~60%。
(3) Temperature of copper plate printing workshop should be controlled at 18-25 C and relative humidity should be maintained at 50-60%.
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