The corrugated industry has one thing that most of the others don’t – an unpredictable, uneven, porous substrate that will vary from not only run to run but also within the run itself due to variations from lot run to lot run of linerboard from the papermills. Then corrugated sheets have been bonded with heat, steam and starch. These properties create situations that challenge us everyday.

You can have the very best, technologically advanced printing machine available to your market, but if you have poor process controls you will never have a high quality job. The printers/converters that have control over their process – no matter if they are printing one-color on kraft liner or CMYK on coated liner – will succeed in the marketplace.

Clean Pressroom

In printing, cleanliness – and good organization, is key to high-end printing.

  • Make sure consumables are kept close so that the operator and helper do not have to leave the area to get that – things like replacement doctor blades, foam end seals, cleaners and the like. Keep an inventory of thee items close by in a storage cabinet.
  • Keep a file of job folders for each project/job so that information is available when the item is run again. Keep it up to date with history information so that if issues occur, they can be identified and solved before the next set-up.
  • A pressroom that is disorganized and cluttered will be distracting for the operators, and also lead to inefficiency (“Where is the mounting tape?”, “I can’t find the spectro… ah, forget it, it looks fine.”)

Machine Maintenance

The capital cost of corrugated machineries are very high. Therefore a good and routine maintenance will help us to assure that this investment is properly utilize and avoid huge parts and service cost as well as machine down.

  • Ask your press manufacturer to create a weekly checklist.
  • The operator and helper can take a half hour to an hour per week to take care of basic maintenance. Nothing major, just quick checks, filling of oil levels, cleaning air filters and other things.
  • Keep the inside of the presses clean. Try to avoid build up of ink, dust and scraps. This can cause not only machine failures but also safety hazards. Make sure all moving parts are free from obstruction and are properly lubricated.
  • Make sure the ink metering system continually monitored for plugging, dirt and other things that will affect the flow and quality of the ink.

Proper Anilox Rolls

We all know that this is the very heart of the machine. Its cleanliness and state of repair is far among one of the most important elements in making sure your process is under control. Always washup with manufacturer-recommended cleaners after each production. Periodic examinations after cleaning will point out trouble spots before they become a major hassle, which in turn will give longer life to the roll.

Use The Right Plates

Even you just print one-color logo in the middle of a large panel or having process colors on clay-coated liner, the printing plates need to be right for the job and the press. Uderstanding what your needs are for printing plates begins with working with your preferred supplier and coming up with the right hardness and thickness. It is all based on the press, the type of inks you are running and the image is that you are trying to reproduce. In most cases, once you have used a certain type of material, and it is a success, stay with it and keep the changes to a minimum. Work with your supplier to work out the best combination of plate and backing. The higher number of colors required, the more attention you need to pay to how the material will affect the artwork. Make sure things like traps, bleeds, screen counts etc. are analyzed very closely by you and your supplier.

The Right Ink

The ink must be formulated to fulfill your need (see article in ACCA 2). Different anilox rolls, different artwork and different material can all play a part in the needs of your ink. Ask your supplier to help setup proper densities and control readings and training your operators how to read that information and understand what needs to be done to maintain that color will help reduce your downtime and increase your productivity. Be sure to maintain proper ink viscosities and pH levels that are required for each color. Using the spectrophotometer will help you to get the right color and color consistency all the time. To make sure all the utilities are right you need to do fingerprint for each press.

FINGERPRINTING OR CHARACTERIZATION

A printing test plate is specifically designed to evaluate the printing capabilities of the corrugated press with regard to registration, dot gain, gray balance, anilox roll cell count, gray scale readings, impression and ink density. Any mechanical problem in the printing station will surely show up, too. Therefore, finger print should be done when the machine on it good performance and should be on it standard operation set.

Fingerprint is very important to measure and record the print characteristics of a particular press with specific settings and materials. The data from the characterization is provided to the color separator for compensation of graphics to the characterization results. The operator in cooperation with the pre-press staff will use these data to assure print consistentency in day to day production. It become a tools to provide consistency to be measured and analyzed which mean a tolls to reduce waste and improve color quality consistency.

This process especially very important for color process combine with line and solid works. From this process we will learn the capabilities of our machine or each job.

  • The trapping or overprint solid
  • Registration capabilities of the press
  • Density of ink (can be achieved using that specific inik, anilox, plate, tape on the finger print)
  • Hue error (colorspace)
  • Dot gain or dot area
  • What screen line can be printed well
  • UPC bar width reduction
  • What is the smallest font can be print (positif and negative)
  • What line thickness can be printed (especially for barcode)
  • Dot gain

To be sure we do the correct Fingerprint, we must prepare :

  1. Materials used are made to manufacturer’s specifications and tolerance
  2. Correct ink color sequence and viscosity
  3. All substrate used during production are characterized
  4. Take measurements, using calibrated tools and recorded
  5. The right Plates, anilox, mounting materials
  6. The test is run at projected production speeds

Once you understand and know exactly how the press will perform, you can design intelligently. For Example, if registration is a problem, design loosely. If trapping is a problem, do not design one color over another. If screen (halftone) fills in, consider using line art or lower art line screen.

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