|Product Number: 7245A|
|Division: San Diego|
|Ad: Click to see, Click to see|
|Original Price: $4600|
|Catalog Reference: 1979, page 254|
|Donated by: Australian Computer Museum Society|
The 7245A was a long-axis thermal graphics printer. It was both a standard raster printer and an HP-GL vector plotter (the paper moved in both directions when in plotter mode). This sprocket-feed printer could plot images up to 200 feet long (7.4 inches wide). It had a raster graphics print resolution of 106 dots per inch and a vector graphics step size of 0.016mm, better than HP pen plotters of the time. The 7245A printed raster characters in a 9 x 12 dot cell at a speed of 38 characters per second. The 7245A was an HP-GL language machine and came standard with an HP-IB interface. The RS-232 version carried part number 7240A (January, 1980). Click here to view an 11 second video of the 7245A in action (1.9 MB).
The 7245A was a very interesting and unique product. It was the only hardcopy vector product made by HP that used thermal technology. The 7245A was basically a standard printer that could also print graphics at the same quality as HP pen plotters (see print sample). Thermal technology gave the 7245A two advantages over pen plotters - it was quiet, and the user never had to worry about a pen running out of ink. The never-running-out-of-ink benefit was significant because it allowed users to run plots unattended or overnight. The 7245A also had long-axis capability which allowed it to print graphs up to 200 feet long.
7245As are very rare; it is surprising that more weren't built. One of the biggest challenges in running these machines today is availability of media. The museum is not aware of any current sources of sprocket-fed thermal paper. With considerable effort, this media could probably be made up from a standard roll of thermal paper taped on each side to the peeled edges from standard, sprocket-fed, fanfold paper. The spacing between sprocket holes on 7245A media is exactly half of the spacing between holes on standard fanfold paper, so some hole-punching will be required. The museum has a few boxes of original HP media in house. All 7245A shipped with a replacement printhead inside the printer. The two samples at the museum still have their original and replacement printheads intact.
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