InterFlex Dynamic Imaging / IDI
lnterFlex Dynamic Imaging or IDI is a conventional system for the manufacturers of flexographic plates. It is capable of yielding printing results that meet the most stringent quality requirements imposed by today’s packaging industry.
lnterFlex Dynamic Imaging constitutes an important step forward for the flexographic market. Jet Europe/lnterFlex BV has designed the IDI System as an inexpensive means of achieving the highest quality flexographic printing plates. IDI is capable of achieving printing results with a quality comparable to that of gravure printing. IDI guarantees high-contrast flexographic printing results with a high brilliance, sharpness, and resolution.
The system provides the flexographic printer with a significantly improved printing process resulting in a superior print quality. The adjustment times are shorter, production capacity is higher, and the quality of print remains constant throughout the run.
Furthermore, IDI plates run cleaner than conventionally exposed plates. The printer is no longer obliged to routinely stop the press during the run to clean plates.
Conventional vs. IDI
Conventional systems use fluorescent exposure lamps to expose flexographic plates. The combination of this type of exposure source with kreene foil and matte negative film causes light to scatter during the main exposure step. This scattering of UV light produces shoulders around each image on the plate. These shoulders are necessary to anchor each dot, line and character to the floor of the plate. (See Figure 1)
The angle of the shoulder produced is based upon the length of the exposure and the size of the line or dot being imaged. Larger dots and lines require shorter exposure times. Solid areas with small reverses in them also require very short exposures. On the other hand small dots, or even larger but isolated dots, require much longer exposure times to produce enough shoulder to hold them on the plate and keep them from washing away. Difficulties arise when images requiring both short and long exposures appear on the same plate. This is normally the case when line and process images are required on the same plate. Therefore, sacrifices in print quality and sharpness must be made when using a conventional light source. The longer times needed to hold highlight dots will produce high shoulders that fill in the reverse area of coarser screens. Conversely, shorter times that favor larger dots will cause highlights to wash away. Figure 2 represents 4, 8, 12, and 16 minute exposure examples.
- After a 4 minute exposure the degree of polymerization is completely insufficient for an effective attachment.
- After an 8 minute exposure the attachment of the larger components of the image is virtually complete, but smaller components of the image are washed away during the washout process.
- After a 12 minute exposure all elements of the image have been held, although the attachment is not yet optimal for the finest details. Washout solvents saturating this image can cause problems for finer dots and delicate copy, This is illustrated in Figure 3.
- After a 16 minute exposure the finest details are anchored correctly, but the reverses have now become so shallow that they can fill with ink as shown in Figure 4.
A longer main exposure time is generally chosen in order to ensure that the finest details (fine lines, minimal letter fonts, the smallest reproducible half-tone dots, etc.) are retained during the washout process. But, the disadvantages of a longer exposure time are a reduction in the quality of the tonal reproduction, a loss of definition, and shadows with little detail. The overexposure is also detrimental to the printing curve.
There are consequences for using conventional lamps for process print copy. Highlight dots will be washed away resulting in a coarse appearance. The transition from “no dots” to the smallest dots held on a vignette is very abrupt, defeating the overall visual graduation effect to be conveyed. The best solution possible is to restrict dot size in the negative so that all aspects of the image can be held at normal exposures. This however, will result in a loss of detail and diminished contrast. Figure 5 below uses graduated tones to visualize these effects.
Another practice used is to over-expose the plate to hold the smallest dots. While the highlights are held, the mid-tones and shadows are deficient in detail. This will also make the reverse area between dots very shallow causing dirty print as accumulated ink in these areas come in contact with the substrate. The reverse areas in larger solids will also be shallow and lack definition.
The IDI System will solve these problems. The shoulder between the image components in Figure 6 is sharply defined, without irregularities, and is suitably steep. The details of the images achieved using the IDI System, in combination with the qualitative advantages offered by Jet Flex Photopolymer plates; result in the clean, crisp print quality due to a strong but tapered shoulders anchoring the image to the plate. Plates will remain clean from the beginning to end of the run. IDI is recommended for packaging printers who need to print lists of ingredients in a number of scripts, such as Arabic, Japanese, or Chinese characters. Fine text produced onto flexographic plates have a tendency to merge or clump together. Plates manufactured using the IDI System are sharper and more clearly defined than those copied by other techniques. The same is also true for half-tone illustrations. The shoulder between the half-tone dots is taut, steep, and without irregularities. All half-tone dots are printed crisply, and the spaces between the half-tone dots remain clean throughout the printing run. The dot enlargement is minimal.
The IDI Advantage
The plate is exposed using a principle that differs from conventional techniques. The UV source is a point light lamp. Light is guided to the plate using special reflectors and has an adjustable output. The main exposure is conducted automatically in 2 consecutive steps. The initial exposure with a non-scattering point light source creates sharply defined lines and dots without shoulders. This image produced in this step is optimum, but is without the necessary shoulders. The 2nd step of main exposure is carried out using a filter. This filter scatters the light as in conventional units and produces the needed shoulder. Figure 6 displays the sequence of polymerization during the exposure of the plate.
The IDI Flexo Curve
The red flexo curve shows the curve measured after an “over-exposure” of the flexographic plate designed to retain the smallest reproducible half-tone dot possible on the plate. The blue flexo curve shows the result obtained using a flexographic plate manufactured with the IDI System. The figure shows very clearly that the IDI curve is very favorable in comparison to the repro curve; the amount of detail lost subsequent to the repro correction is directly proportional to the amount of the repro correction required to achieve a satisfactory result. When expressed in terms of the smallest possible reproducible half-tone dots, the IDI System compares to conventional imaging as follows:
1 % on the film remains on the flexographic plate subsequent to overexposure and the washout process. Once printed, this 1 % becomes at least 12%.
1 % on the film remains on the flexographic plate after the washout process, the result of the innovative manufacturing technology employed in the IOI System. When printed this 1 % becomes a maximum of 4%. In other words, there is minimal dot gain from the smallest highlight dots when utilizing IDI. This makes it possible to achieve a print result with a great deal of contrast and with a high degree of brilliance, definition, and resolution. With the introduction of the IDI System, flat and poorly defined flexographic full color prints have become a thing of the past.
Why an IDI System?
The combination of the I DI exposure unit and the lnterFlex Washout Unit offers the flexographic printing industry a quality that satisfies all the modern packaging industry’s requirements. The most important reasons for choosing the IDI System are the savings achieved over alternative expensive plate reproduction technologies, and its reduced environmental impact. You will be amazed by the IDI System’s ability to produce flexographic plates with remarkable quality and for such a small investment.
The extremely low costs, extremely high quality and extremely interesting economics of the IDI System as compared to Computer to Plate technology will enable flexographic printers to satisfy all their client’s needs and requirements with ease and affordability.
Contact Jet USA Corporation for information about the cost/performance ratio of IDI as compared to the other systems available on the market.
IDI offers flexographic printers these advantages:
- Higher printing speeds
- Shorter adjustment times
- Plates remain clean throughout the printing run
- No variations in print quality throughout the printing run
- Substantial row material savings
IDI offers flexographic plate makers these advantages:
- Low investment
- High flexographic plate manufacturing capacity
- A predictable and consistent quality
- Savings in the costs to flexographic plate manufacturer
IDI offers the flexographic printing market these advantages:
- A general upgrade of quality in flexographic printing
- Digital quality without the digital price tag
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