What is a plotter?

If you are trying to find a definition of a plotter, you've come to the right place. Our site is packed with information about HP's current 'plotters' - although these are now known as Designjets (or Large Format and Wide Format Printers). Although the term 'plotter' still persists today, the technology now employed no longer actually 'plots' the output due to a change in printer design and technological advances.

HP Plotter History 1968-1990s

In 1968 HP introduced their first plotter - the 9125A flatbed plotter - designed to be used with the 9100 calculator and connected to the I/O slot at the back. This plotter famously made an appearance in the 1971 movie “The Andromeda Strain”. After the 9125A, HP continued designing new plotters based on the original 9125A design until 1977.

During this time, the only way for a business to get high resolution graphic output from computers was through pen plotters. Pen plotters provided a variation of resolution between 72 dpi and 100 dpi and line resolution equivalent to 1000 dpi. By 1977, HP started to introduce different style plotters which would carry a greater number of pens (which were capped to stop them from drying) together with improved reliabilty and roll feed capability.

At the end of the 1970s HP then introduced paper moving plotters to replace the old flatbed technology (making the printers cheaper and smaller). The HP plotters employed a technique of physically moving pens across a carriage while moving a sheet of paper back and forth under the pens. This enabled the device to draw (or plot) any shape needed by the drawing. This was a great way of producing line drawings, but not so good at creating solid blocks of colour. These plotters took a long time to produce a drawing by today’s standards, typically taking 5 minutes to produce an A4 line drawing while an A0 output could take upwards of 45 minutes. Sometimes the plotter pens could dry out mid-plot (especially pre-1977 models) which meant the whole print process had to start again.

In 1981 HP notably entered the large-format plotter business (previously the domain of companies like Calcomp and Versatec) and within 6 years commanded a market share of almost 50%. Following on from the success of the DraftPro and DraftMaster range of plotters, HP introduced the 7600 series mono Electrostatic Plotters in 1988 - providing colour models in 1990. However the Electrostatic Plotters were short-lived because in the early 1990's they introduced the Designjets that you see today.

The introduction of HP Designjets

Following the introduction of HP Designjets, the Electrostatic Plotter market collapsed very quickly because the Designjets combined lower capital + lower operating costs.

These devices used a technique for dropping tiny ink droplets onto the paper. This meant that the paper only needed to make a single pass through the machine while the print heads moved side to side dispensing ink, massively improving performance and reducing output times to seconds rather than minutes.

This new technique was much better at creating solid blocks of colour and didn’t suffer from pens drying out midway through a drawing, but initially the ability to create solid continuous lines was not as good as that of the older style plotters. As with all things, time brought progress.

The Designjets have now moved up from 4-6 colours up to 11 colours (plus gloss enhancer) for the photographic range of Z series Designjet printers. Printing ranges from 24”-60” wide rolls with some machines capable of alternating 2 different size rolls of paper and/or handling upto 91.4m length rolls.

Historical HP Plotter Models (all key information taken from www.hpmuseum.net)

• 9125A flatbed plotter - HP's first flatbed plotter – designed to work with the 9100 calculator using electrostatic paper hold-down, which plotted 10”x15”. (1968)
• 72xx series flatbed plotter – 1 pen plotter – worked with most computer terminals and plotted 10”x15”. (1971/1972)
• 9862 flatbed plotter – Mechanically almost identical to 72xx series plotters, and designed for connection to HPs 98x0 computers (1972)
• 9872 flatbed plotter - HP’s first multi pen plotter which replaced the 9862. The first 9872 had 4 pens which were capped to prevent the pens from drying out. The 9872s added automatic rollfeed capability and the 9872C carried 8 pens (1977).
• 7221 flatbed plotter - 1 pen plotter – designed for computers that did not output HP-GL instructions - this was a version of the 9872 flatbed plotter.
• 7225 flatbed plotter – 1 pen plotter (uncapped) provided reduced costs and improved reliability with improvements in electrostatic media holding technology (1978)
• 7220 flatbed plotter – incorporating HP-GL language (1979)
• 7580 – HPs entry into the large format plotter market – code named “Bertha” this was the worlds first “grit wheel” pen plotter and combined high speed with high line quality at c50% of the price of comparable products manufactured by Versatec and Calcomp creating a storm in the marketplace (1981).
• 7470A – 2 pen plotter (using short body fibre tipped pens) which plotted on A4 size media and formed the world’s first small format paper-moving plotter – this was a replacement to the 7225A flatbed plotter and proved very reliable with higher speed. (1982)
• 7585A – This replaced the 7580 capable of printing up to A0 size by roll feed and used short body fibre tipped pens. (1982)
• 7475A - 6 pen plotter for use on A4 and A3 paper – and especially popular for Lotus 123 applications. This was a replacement to the 9872 at a fraction of the price with better performance but without the roll feed or liquid ink drafting pens (although by 1985 a special carousel was introduced allowing it to use the liquid ink pens) – and with 2 pens less than the 9872C version. This proved to be HPs most profitable single product and most popular pen plotter ever made (1983).
• 7090A – A digital plotter and HP-IB analog instrument recorder compatible with the 7475A (1984)
• 7550 - 8 pen plotter which could plot on many different types of media. Very reliable and “most advanced small plotter ever built”. This machine used both short body fibre-tipped pens and long-body roller ball and liquid ink pens, with the capability of automatically adjusting pen speed and tip force for the different types of pens. The 7550B also offered memory upgrades (1985)
• ColorPro – 8 pen plotter, plotting on A4 media and priced one third less than the 7475 model – however initially sales were far below that expected by HP although it did eventually take 50% of the volume of 7475 sales (1985)
• DraftPro – Sheet feed plotter with maximum of A1 plot size – designed as a low end large format printer. Slower than the 758x series. (1986)
• DraftMaster – Roll feed plotter with maximum of A0 plot size. Replaced 758x series plotters . HP/GL-2 language capability and faster speed added in 1990. Noted as being the “most advanced pen plotters ever made by HP”. (1987)
Until 1987, HP Plotters were the only cost effective method of getting graphic output in colour from computers and despite limitations (i.e. could only draw lines and vectors, couldn’t reproduce raster or photographic images) they proved to be the colour output device of choice – with HP enjoying over a 50% worldwide market share.
• DraftPro DXL – A slightly faster version of the original DraftPro – this was later replaced by the DraftPro EXL which provided AO plot size (1988)
• 7600 Series Electrostatic Plotters – A1 & A0 size electrostatic mono printers – HP later introduced colour in 1990. (1988)


The ColorPro Plotter introduced in 1985


Draft Master introduced in 1987


Please find below 3 other explanations we have found for you on google which might also be helpful.

What is a plotter?

Please find below 3 other explanations of "What is a plotter" taken directly from three informative websites that we liked!

1. What is a plotter?: "A plotter is a computer printing device for printing vector graphics. In the past, plotters were widely used in applications such as computer-aided design, though they have generally been replaced with wide-format conventional printers. It is now commonplace to refer to such wide-format printers as "plotters," even though they technically aren't". Pen plotters print by moving a pen or other instrument across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. Pen plotters can draw complex line art, including text, but do so slowly because of the mechanical movement of the pens. They are often incapable of efficiently creating a solid region of color, but can hatch an area by drawing a number of close, regular lines. Plotters offered the fastest way to efficiently produce very large drawings or color high-resolution vector-based artwork when computer memory was very expensive and processor power was very limited, and other types of printers had limited graphic output capabilities. Pen plotters have essentially become obsolete, and have been replaced by large-format inkjet printers and LED toner based printers. Such devices may still understand vector languages originally designed for plotter use, because in many uses, they offer a more efficient alternative to raster data".
http://en.wikipedia.org/wiki/Plotter

2. What is a plotter?: "A device that draws pictures on paper based on commands from a computer. Plotters differ from printers in that they draw lines using a pen. As a result, they can produce continuous lines, whereas printers can only simulate lines by printing a closely spaced series of dots. Multicolor plotters use different-colored pens to draw different colors. In general, plotters are considerably more expensive than printers. They are used in engineering applications where precision is mandatory".
http://www.webopedia.com/TERM/P/plotter.html

3. What is a plotter?: "A plotter is a vector graphics printing device that connects to a computer. Plotters print their output by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. They can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Another difference between plotters and printers is that a printer is aimed primarily at printing text. This makes it fairly easy to control, simply sending the text to the printer is usually enough to generate a page of output. This is not the case of the line art on a plotter, where a number of printer control languages were created to send the more detailed information like "draw a line from here to here". The most popular of these is likely HPGL. Early plotters were created by attaching ball-point pens to drafting pantographs and driving the machines with motors controlled by the computer. This had the disadvantage of being somewhat slow to move, as well as requiring floor space equal to the size of the paper. Later versions worked by placing the paper over a roller which moved the paper back and forth for X motion, while the pen moved back and forth on a single arm for Y motion. Another change was the addition of an elecrtically controlled clamp to hold the pens, which allowed them to be changed and thus create multi-colored output. For a time in the 1980's smaller "home-use" plotters became popular for experimentation in computer graphics. But their low speed meant they were not useful for general printing purposes, and you would need another conventional printer for those jobs. With the widespread availability of high-resolution inkjets and laser printers, plotters have all but disappeared. Plotters are used primarily in drafting and CAD applications, where they have the advantage of working on very large paper sizes while maintaining high resolution. Another use has been found by replacing the pen with a cutter, and in this form plotters can be found in many garment and sign shops".
http://bugclub.org/beginners/history/PlotterHistory.html