Laser drum cartridge key print quality evaluation

Due to the huge market space, domestic manufacturers involved in the size of laser drum cartridges are said to have reached as many as 600, and the price competition is fierce. Of these, there are only a handful of people who have the technology and manufacturing capabilities. Most of them belong to the assembly of parts, recovery and refurbishment, and the regeneration of old parts. The corresponding product quality level must be high or low. With the maturity of the market, users began to pay more attention to the quality of the laser drum cartridges. This is no longer the same as when “putting out words on the line”. Some requirements are quite professional, which puts higher demands on the manufacturers and manufacturers.

The factors affecting the laser drum cartridge print quality include: photoconductor drum, magnetic roller, charging roller, scraper, toner, etc., as well as mutual compatibility and working stability. There are more than ten quality indicators for evaluation of drum kits, and the market response is not the same. For example, there are few problems with the two important indicators of resolution and hierarchy. We will focus on discussing what the market is most concerned about. The following is a key quality evaluation method based on HP5L/6L/1000/1200 and other drum kits, summed up from actual combat experience, and hopes to help users use quality assurance.

First, evaluation of blackness

Most users require that printed text (especially bold and large letters) be black and solid in order to guarantee a beautiful appearance. This

It is the most basic requirement for use.

The industry term says that blackness is image density, which reflects the degree of textual darkness. It has 6 solid circles with a diameter of 6mm distributed on the surface, middle and lower areas of the standard print test panel, and is measured using an optical density reflectometer with a resolution of 0.01. The numerical requirement is ≥ 1.3, and the 6-point difference is ≤ 10% (referred to as density non-uniformity). Better blackness can reach 1.5 to 1.6.

In practice, an A4-format test board can be edited under WORD. At least 6 black solid circles (or squares) are distributed in the upper, middle, and lower areas, and the diameter (or length) is 6-10 mm. Visually determine the print effect, it should be black and solid, there should be no significant difference between 6 points. This method can be equivalent to the industry standard test results, and the actual application results are good.

Second, bottom ash evaluation

Bottom ash, also known as fog, is a fog-like gray that appears on the background of the printed manuscript. When it is serious, it can affect the beauty of the manuscript.

Concept. The majority of users are very disgusted with the bottom ash and require very high demands, especially in important occasions (such as proofing, plate making, and bottom drawings). Some merchants and manufacturers have also encountered returns.

The numerical requirement for bottom ash is 0 (this is the market requirement), which is measured with an optical density reflectometer at the background blank of the standard print test layout. However, the actual situation is much more complex, because often the instrument is measured as 0, but the visual is not 0, that is, you can see a faint bottom ash. This has caused disputes and troubles among users, merchants, and manufacturers, and it must be able to solve its determination problem well.

Some manufacturers use high magnification magnifying glass to observe the background ash of the document to determine whether it can be accepted. The disadvantage of this method is that it is not intuitive, it is easy to make people's eyes tired, causing misjudgment, and time-consuming, laborious, inconvenient assembly line operations. Here is a very practical double superimposed printing method to judge. Under WORD, edit a test version with a small amount of text on an A4 format. Select a white copy paper and print the test panel twice on the same side. The images are overlapped, ie, double-stacked. Judging the bottom ash. This method has a "magnifying" effect on the depth of the bottom gray tone, the principle of which is that the density of printed dots increases, so that the invisible bottom ash will become apparent, which is favorable for determination, fast and accurate. In actual combat, we can see that after high-quality double-stack printing of drum kits, there is still no bottom ash—judgment, etc., and low-quality bottom ash is obvious—the quality is judged to be unacceptable, and the bottom ash of intermediate quality is not obvious—the quality is judged to be acceptable. In the case of disputed bottom ash determination, this method is very effective.

Third, gray version evaluation

Gray version is a more stringent print quality evaluation. Edit an A4 format test version under WORD. The layout is gray. Generally, the fill density is 50%. This is the gray version. It can be used for demanding print tests to meet the print quality requirements of high-level applications such as pictures, layers, network lines, fine words, and large letters.

Gray print quality can be roughly divided into A, B, C three levels. Grade A is an excellent product. The full-width color is very uniform and detailed, with almost no imperfections. The printed documents are very beautiful. Grade B is a qualified product, full-format tones are not exactly the same, slightly periodic horizontal light white bars, there may be light spots, lines, etc., but these have almost no effect on the printing of the above-mentioned high-demand documents, which is the gray Basic requirements for printing. Grade C is non-conforming product, full-width non-uniformity, periodic horizontal light white bars are obvious, there may also be obvious spots, lines, strips, etc. It may be okay to print general drafts.

It is worth pointing out that the grey version evaluation has in fact become an important measure of the quality of the industry's products. Some companies have exerted great efforts to overcome this difficulty, and thus paved the way for large orders, OEM cooperation.

Fourth, life assessment

In a narrow sense, the laser drum cartridge print life refers to its nominal printable number of sheets. Printed papers are designated as industry-specific test versions with 5% text coverage, which is referred to as consumption edition. Generally can print 2300 ~ 3000, depending on the type of drum kit is different, during this period should ensure that the quality of sampling inspection qualified, that blackness, bottom ash, gray version, etc. should meet the requirements, and no other print defects, such as spots , missing print, uneven, lines, poor levels, poor resolution and so on. Consumption version can also be edited under WORD A4 format with a certain amount of text to replace.

Life assessment is time-consuming, costly, and sampling is generally used. Two new drum cartridges may not perform poorly at the beginning of printing, and they begin to differ as the number of prints increases. High-quality drum cartridges are guaranteed to have a long life, while low-quality drum cartridges are difficult to guarantee. Often, the number of prints is not enough to specify the number of sheets or the quality of the print is degraded, and even a few hundred prints have become ineffective. Life assessment is an important indicator of the industry's product quality level. It is highly valued internationally and has one-vote veto power. It reflects comprehensiveness and strictness to the manufacturer, and reflects practicality and economy for the user. In the face of large orders and OEM cooperation, it is an important quality barrier that must be faced.

V. Conclusion

The above four key indicators, blackness, bottom ash are the basic requirements that must be met; gray version, life expectancy is a deeper level, especially for advanced users, large customers, OEM orders. The four indicators were successively increased and the evaluation difficulty increased in turn. For the first three indicators, a "limit sample" method can be used to facilitate rapid determination of mass production. It is to obtain a printed sample draft in advance and use it as a benchmark for comparison. If the print quality is higher than or equal to the sample, the sample is qualified. If the sample is lower than the sample, the sample is rejected.

The laser drum industry has not started in China for a long time, and the quality level is far from that of foreign countries. We have a lot of work to do. We must continue to overcome difficulties and strive to enhance ourselves in terms of technology, manufacturing, and quality in order to participate in international competition.

Source: Han Hanguang Office Automation Consumables Co., Ltd. Han Guang Office Equipment Division Bai Jinning