Guide to Offset Printing
What are offset printing machines?
Offset printing equipment is meant for large scale print jobs with printing towers stacked with inks, rollers, splicers and heating elements. These presses use cylindrical drums or rollers arranged in a sequence to impart ink to the medium running through. It can also handle a variety of paper sizes, quality and volume.
What are Digital Offset Printing Machines?
Digital offset presses are best suited for premium quality, multi-color print feeds. They adapt admirably to both small and large quantities providing prints from offline digital files -based program such that it’s easy to change and not mechanically constrained.
Digital printing offsets are new age machines so incorporate the best of technological improvements in productivity, efficiency and outputs.The current generation is all about digital displays and marketing, hence this category is the current trend.
There are many manufacturers available and generally they print in thousands per hour hence suitable for very large-scale production jobs. They are also sized smaller especially helpful where land is expensive helping maximize the factory floor space. They do not have any constraints in terms of either thickness of paper or detail in quality, its as good as offset printers.
Unfortunately, they can be expensive and sometimes out of reach for importers.
What are Sheetfed Offset Printing machines?
If the job requires singular feed of paper with content being streamed one after the other, Sheetfed printing offset machine is the one used for this run. Whether it be designs or content being printed on individual paper, cardboard, or other mixed media, the key focus is on the need for the medium to be streamed in one after the other.
Sheetfed presses are usually preferred for less volume jobs such as pamphlets, printouts, marketing material, weekly magazines, regional publications and other non-voluminous printing. It does provide great versatility in terms of both printing mode variety of media and colors.
These can also print up to 20,000 per hour with very large print sizes. The quality of print and color can range from low to top grades, essentially providing commercial printers the ability to manipulate pricing to suit contracts.
Given the offset is not digital, the plating is manually registered therefore it cannot be altered and will always print at the same position for each sheet that feeds through the offset.
What are Web Offset Presses?
Continuous production of long content with paper reams rolling at high speed defines a web offset press. It is also how the word “press” is used to describe news media, as the output was printed with a offset press.
Imagine a sensational piece of news in a movie being printed in a newspaper factory with newspaper spinning at high speed. That right there is the work of a web offset printing machine. The press works by cutting paper first and loading into the feeder section. Cyan, Magenta, Yellow and Black are the first to go onto the paper. There could be a fifth tower that is used for some sheen, varnish or optional color if required.
These machines are known for their temperature detail to the process, where there is a “Cold” and “Hot” sections. The wet ink from the color towers are cooled, dried in a hot oven for mass and rapid moving outputs. Heat set printers utilize high temperature lamps or elements to dry the inks; they are normally used on coated or glossy paper. The cold web offset process is where ink drying happens slower into the paper essentially lending to low quality and slower production runs.
Depending on the machine, it can run 3,000 feet per minute and upto 25K paper reams cut per hour. Unfortunately, this type of press is facing declining demand and brands are slowly shrinking.