Как правильно оценить эффективность печатной машины

Methods for Correctly Evaluating the Working Performance of a Printing Press

To make a correct evaluation, the following three aspects of

work requirements are specifically put forward.

Working performance mainly covers three indicators: register accuracy, ink color uniformity and productivity.

In the process of multicolor printing, the precision with which the printed images overlap is

one of the main technical indicators of working performance. In the process of multicolor printing,

the transfer, handover and printing of the paper, whether at low or high speed, must all be guaranteed to take place at the specified positions. For fine printed products and color printing, this is even more important. This requires that

the position and timing of paper transfer and handover, as well as the transmission accuracy of the printing plate and the impression mechanism, must all meet certain requirements. Therefore, when we analyze

we must focus on understanding the various links related to register accuracy

and grasp their characteristics and the role they play.

Ink color uniformity refers to the consistency of the ink layer thickness on the printed product and the clarity of the ink imprint. This is another indicator for measuring print quality, and is also valuable in evaluating

an important element of working performance. Whichever printing method is used, to print products with clear and solid ink, not only uniform ink color is required

but also sufficient printing

which requires that the printing unit, including the ink supply

and so on, should have relatively high precision and performance.

The productivity of a press is generally expressed by printing speed. As for how printing speed is expressed, for sheet-fed presses

it is expressed in sheets per hour; for web-fed presses

the structural composition and characteristics, as well as

the technical level are the main factors determining the level of productivity. For example, the flat-bed press

adopted an impression cylinder, and compared with the flat-bed press

its printing speed was significantly improved, but the reciprocating motion of its bed plate again limited any further improvement in productivity, so it was gradually superseded by the cylinder-on-cylinder press

At present,

presses are developing toward large formats, higher speeds and inline linked operation, so as to maximize productivity.

The usability of a press mainly covers operating performance, safety and reliability, and durability.

while the degree of automation, good operating performance must also be ensured.

Generally a press occupies a relatively large floor area, so several sets of control panels should be provided to ensure that operators can operate from every main working position. Each control panel must conform to human motion habits, the working position should be easy to observe, and the adjustment points should be intuitive and easy to reach.

Safety and reliability performance

In order to ensure the personal safety of operators and

on the machine, besides being fitted with safety

devices, safety devices must also be provided

devices, safety and insurance devices must also be provided

so that once the machine fails it can

After long-term use it can still maintain its original precision, that is, the machine has a long service life, which is of great economic significance both to the country and to the enterprise. To achieve this, part materials and heat treatment processes should be selected rationally to ensure the parts'

properties; in order to improve the transmission

each mating surface should have reasonable geometric shape accuracy together with good fitting clearance and lubrication devices.

on the premise of satisfying the main working performance, the structure should be as simple and compact as possible, with good manufacturability, lower manufacturing cost, and ease of assembly and maintenance.

The above requirements often constrain one another and are mutually contradictory. For example, improving register accuracy is not easy to achieve at high operating speeds. This is because any further increase in printing speed brings new problems: the fast and accurate handover and transfer of the paper,

the fast drying of the ink and the smoothness of the moving parts will be greatly affected,

making register accuracy hard to guarantee. If control devices are added, the manufacturing cost of the machine rises. To take another example, between a simple structure and a higher

degree of automation, and between printing speed and service life, certain contradictions exist. Therefore we can only take the above requirements as the starting point for analyzing the problem

and, according to the demands the printing process places on the machine, grasp the principal contradiction and the weak links, weigh priorities from an overall standpoint, and properly resolve the secondary contradictions on the premise of meeting the main requirements. This is also the way of thinking that the research and design of

printing presses should follow

——This article is reprinted from China Packaging Network (pack.cn), original link: http://news.pack.cn/show-369994.html