Prepress industry how to choose a good density meter (below)

2. Reasonably used a new type of electronic light source

Since the densitometer is used to replace the human eye to quantify the measured luminous flux, the ability to accurately simulate the visual function of the human eye becomes a key issue. So far, many brands of black and white densitometers still use white light as a light source. After considering the spectrophotometric values ​​of other optical devices, especially the relative spectral sensitivity of photodetectors, they eventually rely on color filters to form “human eye vision”. Function curve". Obviously, this traditional design can only be an approximation. Imagine if the filters are so "magic" that the entire prepress process would not have to be so complicated. In recent years, a new type of electronic light source has been introduced. The spectral energy distribution of the light source not only meets the requirements but also can continuously work for more than 50,000 hours, which has far exceeded the service life of incandescent lamps.

3. Extraordinary anti-interference ability

For a long time, domestic and foreign densitometer manufacturers have always been confused by the problem of light interference. Because the interference of external stray light inevitably occurs in the process of detecting the sample, this particularly affects the measurement accuracy of the high density value. TD-210D density meter in the design, manufacturing process, in addition to optical machinery to minimize this light leakage phenomenon, but also in the circuit design using advanced lock-in amplifier and intelligent frequency modulation technology. The special light source driving frequency can completely avoid the interference of outside sunlight (DC) and light (50Hz). Even if there is a small amount of stray light leakage, the narrow-band filter inside the machine can be completely filtered out, so that this problem can be successfully solved.

As of this writing, I would like to give a more typical example. A few years ago, once a user had purchased the machine the next day he rushed to call for a return. It turned out that because of doubts about the quality of domestic density meters, it has been urgent to bring the machine to Shanghai to a large-scale enterprise to compare with two imported density meters. The results show that the test results with the two imported densitometers are almost the same, but the difference with the domestic machine is very large. After investigation, it was discovered that the user's product was a typeface plate made of dry glass, and the 3mm thick glass plate acted as the main culprit for introducing stray light into the room. After a simple experiment of repeatedly turning on the indoor lighting, the final result has left all the staff in the room convinced.

4. Smaller measurement aperture and higher density limit

Film on the film will inevitably have trachoma, so densitometers usually use a larger measurement aperture to reduce this effect, almost all densitometer manufacturers are very clear, a measuring aperture of φ3mm aperture than the effective area of ​​φ2mm aperture To increase 2.25 times. For this reason, many models use the φ3mm measuring aperture diaphragm as the basic configuration, and all the technical specifications are also developed below. This makes it impossible for the user to measure the density or dots in some small and important parts. For example, the high light spot on the human eye part of the screen cannot always be measured with black eyes and white eyes. Another example is that small and important prints such as stamps are difficult to measure. To solve this problem, the TD-210D Densitometer uses the φ2mm aperture of the measuring aperture as the basic configuration. The user can also choose other apertures with ≤φ1mm aperture. The measurement aperture of φ2mm will have more than one hundred mesh points, and the confidence of its measurement result is sufficient.

Using a small measurement aperture inevitably reduces the maximum density range of the densitometer. Although the upper density limit of 4.5 is sufficient, if the upper density limit of the density meter can be made higher, the lower density value can be trusted. The higher the degree is. This is because the linear range of photodetectors selected by this type of densitometer is wide, and the circuit is very strong in terms of weak signal processing and anti-interference ability. It will undoubtedly be a kind of high-grade model. At present, the TD-210D density meter has been carefully designed and has been able to achieve a φ2mm aperture measurement. The upper limit of the density can be as high as 6.0, which is still rare in the current market.

5. Unique single-button multi-function operation

As the saying goes: "Technology is simple and easy to use," and the TD-210D densitometer is the best proof of this sentence. The operating part of the whole machine has only one button, and it does not depend on the additional key modes such as fast, long time, and multiple presses to achieve “zero setting”, “constant density”, percentage of outlets, and percentage of outlets. "Continuous Density" converts these three functions to each other. This is an advanced design concept that cannot be matched by any density meter at present, and it is very popular among users.

Third, the conclusion


In the color printing industry, density is the only one that can be consistent throughout and is one of the most important parameters. Therefore, it is very important to choose a high-quality, inexpensive and high-density densitometer. In the research and development process, what we feel most deeply is how difficult it is for a domestically-made machine to stand on the market. This is probably because we do not want to rely too much on advertising, but rather on the basic idea of ​​the inherent quality of the densitometer. It is true that TD-210D densitometer still exists in places where the appearance of the TD-210D is not perfect. If the user does not care about this at the moment, it will not have any worries if he only pays due attention to cleaning work. According to the feedback from the recent two large-scale exhibitions, the TD-210 densitometer has returned less than 0.3% after 10 years, and its quality should be completely trustworthy.

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