Depending on the type of product ordered. We at SBDC use each of the following methods to ensure that the end result is the absolute highest quality for the price. No one produces standard print products at better quality for less money.
In sheet-fed offset, “the printing is carried out on single sheets of paper as they are fed to the press one at a time.” Sheet-fed presses use mechanical registration to relate each sheet to one another to ensure that they are reproduced with the same imagery in the same position on every sheet running through the press.
The actual process of printing is quite involved. One of the most important functions in the process is pre-press production. This stage makes sure that all files are correctly processed in preparation for printing. This includes converting to the proper CMYK, finalizing the files, and creating plates for each color of the job to be run on the press.
The sheet fed press consists of different systems that complete the actual process; feeder system, printing system, inking/dampening system, and the delivery system.
The feeder system is responsible for making sure paper runs through the press correctly. This is where you load the substrate and then correctly set up the system to the certain specifications of the substrate to the press.
The Printing Unit consists of many different systems. The dampening system is used to apply dampening solution to the plates with water rollers. The inking system uses rollers to deliver ink to the plate and blanket cylinders to be transferred to the substrate. The plate cylinder is where the plates containing all of the imaging are mounted. Finally the blanket and impression cylinders are used to transfer the image to the substrate running through the press.
The delivery system is the final destination in the printing process while the paper runs through the press. Once the paper reaches delivery, it is stacked for the ink to cure in a proper manner. This is also where you can check on sheets to make sure they have proper ink density and registration.
Production or impact of double image in printing is known as ‘slur’.
Web offset presses are beneficial in long run printing jobs, typically press runs that exceed ten or twenty thousand impressions. Speed is a huge factor when considering turn around time for press production; some web presses print at speeds of 3,000 feet per minute or faster. In addition to the benefits of speed and possible faster turn around times, some web presses have the inline ability to cut, perforate, and fold.Heatset web off
This subset of web offset printing uses inks which dry by evaporation in a dryer typically positioned just after the printing units. This is typically done on coated papers, where the ink stays largely on the surface, and gives a glossy high contrast print image after the drying. As the paper leaves the dryer too hot for the folding and cutting that are typically downstream procedures, a set of “chill rolls” positioned after the dryer lowers the paper temperature and sets the ink.
The speed at which the ink dries is a function of dryer temperature and length of time the paper is exposed to this temperature. This is one of the limits on print speed in a heatset press.
This type of printing is typically used for magazines, catalogs, inserts and other medium-to-high volume, medium-to-high quality production runs.
Coldset web offset
This is also a subset of web offset printing, typically used for lower quality print output. It is typical of newspaper production. In this process, the ink dries by absorption into the underlying paper. A typical coldset configuration is often a series of vertically arranged print units and peripherals.
As newspapers seek new markets, which often imply higher quality (more gloss, more contrast), they may add a heatset tower (with a dryer) or use UV (ultraviolet) based inks which “cure” on the surface by polymerisation rather than by evaporation or absorption.