The HP Indigo 5500 Digital Press | Part 1

Print History

Welcome back to our Behind the Print series. In Part 1 we’ll be touching on the history of print and highlighting the differences between traditional offset and digital printing. In Part 2 we’ll go into greater detail about our HP Indigo 5500 digital press and how it functions.

Modern offset printing can trace its roots back to the Gutenberg Press of the 1400s; operating this press involved setting “type” or metal letter stamps on a tray, inking the type, and applying pressure to paper in order to transfer the ink from the type to the paper (much like letterpress printing today). This process remained largely unchanged for centuries, until the rotary press was invented in the middle of the 19th century. The rotary press improved on existing printing technique by replacing the tray of type with a cylinder, increasing production speed from thousands of prints (or impressions) per day to millions.

Offset printing is the modern equivalent of this process. First, the image to be printed is transferred it to a printing “plate”. Next, this plate is wrapped around the print cylinder and the ink is applied to specific areas of the plate to be transferred to paper. This type of printing is extremely efficient for large runs consisting of thousands or tens of thousands of pieces, and the print quality is often very high. The downside is that offset printing involves a lot of setup, each job must be turned into a plate before the printing begins, which makes it cost prohibitive for printing low quantities.

Offset image plates are wrapped around cylinders.

Digital Print

Digital printing is the next step in the evolution of the industry, and can be divided into two different categories. Dry toner based printers fall under the digital umbrella, and are popular in office environments where high quantity, low cost printing is necessary and quality is not a large concern. Xerox, Kodak, and Canon are all common names in the dry toner print arena. Dry toner printers operate by applying a colored powder to the paper followed by a high temperature in order to bake the toner onto the paper. This process often results in poor color accuracy, banding and ink that will chip and flake off of the paper as it is used.

The other main category of digital printing is wet toner, a technology that is unique to our HP Indigo 5500 digital press. Wet toner printers operate by mixing very small ink particles in an Isopar solution and applying it to the paper. After this, heat is used to steam off excess oil and leave ink particles embedded in the surface of the paper. This process results in rich, full colors and a print quality that matches that of offset equipment. Digital printing is very cost effective for short runs and variable artwork. Setup takes very little time and switching between jobs is easy to do.

Wet toner delivers smooth coverage and does not cover up the natural textures in the paper.

HP Indigo

Indigo was founded by Benny Landa in Israel in 1977 with the goal to lead the current printing industry into the digital era. In the 1980’s Indigo unveiled its incredible  ink technology they dubbed “ElectroInk”. It was called this because of the unique way in which the suspended particles are attracted to the photo imaging plate (PIP). We’ll get into more detail about this technology in Part 2 on wednesday.

Benny Landa (right)

In 2001 Hewlett Packard purchased Indigo and the two companies collaborated on a line of presses that includes our digital press. Indigo is ranked number in the US for digital printing by volume and more than 5,000 of their digital presses operate around the world as of 2009.

That brings us to our HP Indigo 5500 digital press, and the high quality print that it helps us provide to you. We can print on substrates with a thickness of up to 18 points. For a frame of reference, your typical business card is 12-14pt. The sheet sizes that we can print on range from 8.5”x11” to 13”x19”, and all papers are thoroughly tested and certified by the Rochester Institute of Technology to run properly on the HP Indigo 5500. Our printer runs in the CMYK color space, which means the ink colors we have available are Cyan, Magenta, Yellow, and Black (K). In addition to these inks we also have the ability to print white ink, and any PMS color needed for exact color matches.

Check out Part 2 - I go into greater detail about how the press works!

-Spruce
Technology & Research

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