Printer

[bigTomHanks]

Hopefully someone can help me. My company is interested in converting a Windows based CNC Router into an industrial printer. We have some textiles that we are stenciling information onto and would like to use the CNC to do the printing for us. Here is the idea, buy an industrial inkjet printhead and connect it to the computer. I called the inkjet supplier and they said that it has a 44 pin electrical connection. I am looking into finding one with a serial connection though. Can I just connect the printhead to the computer and then just call out each respective jet in the CNC program? (for example move to position x=0 y=0 and turn on jets 1-32, move to x=0.001 y=0 and turn on jets 1-30 until at letter is produced) Would I need to install an A/D card to the computer? Please give me some leads on this.

 

[itsmoked]

wow! Plan on some serious development time. Normally ink-jets have to take into account velocities and delays.

Serial is probably to indeterminate for running ink-jet heads. I bet you can't find one.

All routers of merit use parallel for this reason.

Are you sure you can't turn this into a single spray head? Or several spray heads offset on the z mount? Then you would take alternate passes with an offset for a different color. But at least you would be down to a single digital on-off.

 

[IRstuff]

Are you doing this for kicks, internal use only, or as a product? Is it going to be dual-purpose?

The biggest problem you're going to have is ensuring that the ink wells are full and that ALL the jets are working. There are a series of operations that every inkjet printer goes through prior to printing that are designed to clean the heads and get some semblance of performance. However, unless the printer is used continually, one or more jets will clog and need additional cleaning.

Additionally, you'll need to duplicate most of the actual interface that a normal printer has, e.g., the data buffer and printhead drivers. These need to be synchronized with the movement of the head to ensure that you're printing where you want. You can brute force the synchronization by handshaking between the table and the printhead driver, but the throughput will suck.

Effectively, you need to duplicate all the functionality of a normal inkjet printer, so unless you're doing this for kicks, I'd recommend finding someone who's already done this.

TTFN

 

[Barry1961]

I did something like this years back with a sort of industrial duty dot matrix print head and a two axis pmac for printing numbers on steel sheets. The dots were probably 1.5mm in diameter though. Can’t remember the name of them off the top of my head though. If you can do dot matrix you should be able to find someone easier.

Barry1961

 

[fsmyth]

Sounds like it might be easier to modify a plotter
mech, if the fabric is smaller than "A" size wide.
At least all the code is already done.

<als>

 

[Warpspeed]

I agree with fsmyth, a mechanical plotter would probably be easier to get working.

There are some fairly fundamentally different operating modes for printers and plotters that first need to be understood.

The old ancient style teletype machines, dot matrix printers and daisy wheel printers for example (usually) just print characters. You send the character A and it prints A.

Plotters on the other hand move pens in specified directions to draw lines, and have their own system of communications quite different to a printer. For instance to plot the character "A" would require three individual lines to be drawn. It would work pretty much exactly the way you have described, moving between exact coordinates and changing pen colour.

Those were the old way of doing it.

These days printers and plotters all work in a scanned raster mode just like a TV screen. You send the whole complete "picture" which is a completed assemblage of a vast number of individual coloured pixels.

What you will need is software to convert the output of your CNC machine into a whole finished "picture" that can then be either viewed on a computer screen or printed on your ink jet or laser printer.

If you can get it up on the screen of your computer in final finished form the way you want it, just pressing the "print screen" key on your keyboard should do the rest.

Getting it onto your computer screen may require some software to be written if nothing is commercially available.

Alternatively an XY plotter would move as directed by your CNC machine and you can watch it draw contours or lines as each command is received into the plotter.

This may be easier, but ink pens are a dirty nuisance these days, and may not be acceptable in a new commercial product. But a plotter can be truly large. An A0 plotter could plot full sized engineering drawings,and that may be quite useful in the garment trade, I really don't know. An ink jet printer may be limited to A4 or A3 size.

 

[itsmoked]

Are you just trying to label something or do color pictures?

 

[bigTomHanks]

itsmoked
Just label. We only need to use two different colors about 99% of the time.

 

[bill318]

I was at a trade show a few years back and saw a large plotter(about a 4 ft bed)printing on canvas in full color. It was not real fast but had large ink wells.

I'm not sure if the ink was color fast or not, do you need a "permanent" ink?

You could just attach a sharpie to the tool holder of your CNC and let it etch-o-sketch away!

Or if you print the same label over and over, attach a rubber stamp to the tool head. If your CNC can change tools, have it pick up a different stamp when it needs to.

 

[itsmoked]

bigTomHanks; I would try for a few spray heads-nozzles. Then you can have any color you can make or add to the Pot. Also you can use stuff from the spray industry. You can clean things easily by running cleaners thru the nozzles.

If you want to do dot matrix kind of stuff then one column of spray-heads would let you write any alphanumerics. If the heads need to be really close together you can stagger the heads in a diagonal line and delay the signals to each head.

If you do this, you only need 7 nozzles and hence a printer port would work (8 bits).