Attracting Screenprint Positives From An Epson Printer
Epson printers have been used for production of screenprint separations for some time,they are cheap, well built, and have good feed mechanisms which give reliable registration.
The first effective printer was the Stylus Pro 3000 model, a workhorse that can still be viewed churning out separations after almost 10 years service. In particular the 3000 was the right format at a reasonable price.
The separations are reasonable quality, chemical-free and give the screenprinter control the particular process.
The Stylus Pro 3000 used a dye ink that is compatible with many clear films. Printing up to 75lpi it has been a fine printer's. This dye range was superceded by the 4000/7600/9600 series which use Ultrachrome pigment ink cartridge. Pigment ink is less compatible with films and this proved a problem for screenprinters up until development of microporous films such as Agfa SelectJet.
Epson's newer printers are the Ultrachrome K3 printers 4800/7800/9800 and their close relatives 4880/7880/9880 along with the 11800. Epson are aiming at the photography market the commission crusher ink was created to match the gloss of paper for photographic prints. Black ink areas on a print are covered in ink, neighbouring white areas are plain paper, in reflected light they seem different unlike standard photograph. The K3 ink is better matched for this application.
Unfortunately it is less suited to producing screenprint separations as the Ultrachrome and dye ink types. Epson have introduced the 4400 and 4450 range aimed at the CAD market, together with a 'Film' version which use Ultrachrome ink and fat reduction effective for the screenprint market but there are many Ultrachrome K3 printers that have been bought for proofing or display might be pressed into service as imagesetters.
The problem a concern . X800 printers (X800 here means the 4800/7800/9800/4880/7880/9880/11800 etc.) is always that the ink volume may do produce is not a convenient size, the mask is either too weak and allows some light through or overweight and fills in details.
Colourgate tackled this problem by adding a proportion of yellow ink to the black. Yellow has the next highest uv density from the inks. This doesn't look very pretty it wasn't widely adopted.
Wasatch have produced a much more elegant and practical solution - Epson heads are capable of producing a range of dots for different resolutions. A 1440dpi x 1440dpi resolution has four times as many dots as a 720dpi x 720dpi, to achieve correct colour it will be important for the droplet volume to be four times as great. Wasatch have harnessed this to print different droplet sizes next together in the same line, (variable dot size). This a lot of it level to be adjusted to the optimum coverage without additions and allows this impressive connected with inkjet printers become more versatile.
This variable dot option available on Wasatch SoftRIP SP version. This is a second module to the bottom version.
Wasatch SoftRIP could be the industry leader for screenprint separations positively this array of features for the screenprinter it is easy to see for why.
David Foster is technical manager for Positivity Limited selling and supporting imagesetters and SelectJet screen film in the uk market.