Printing images using 1PC connected to 3 printers

[fotofreek]

The printer functions much slower than data can feed to it and that is why the buffer is used to quickly store the printer data and free up the PC for use while printing is done. I was just wondering if each printer has its own buffer or if all attached printers feed from the same buffer. Doesn't really matter, however, if two printers will print simultaneously as you describe.

 

[alexandereci]

I think there are factors that influence print speeds and PC resources... usb vs parallel cable, and the actual "buffer" that a printer has. I'm not sure if different printers have different sizes of buffers, but IIRC, Canon brochures list the buffer sizes of their printers.

However, I am working with 2 of the lowest-priced printers from Canon, and I'm getting only a little PC performance hit, I presume your mileage will be better with bigger, more expensive printers.

 

[hpnetserver]

A PC's parallel port is a very old piece of I/O interface that needs the CPU's attention to move data from memory to the device on the port. For every 8 bytes of data the CPU is involved once in moving it. Because the printer is very slow you want to give it the data it needs immediately or the printer's movement will be out of sync and motors stop or slow down, etc. So the parallel port I/O will get a pretty high priority to get the CPU's service hence it ignores other tasks running in parallel with the I/O. In the case of USB it is different. The CPU is involved maybe only once. The data will be streamed from memory to the buffer of the printer very rapidly. Each time 16kb or 32kb or even higher is moved. The CPU does not get interrupted as often hence is able to pay attention to other tasks running concurrently. Each PC has two USB ports. If you have more than one printer on each of the USB bus the printer may be slowed down a little, but probably not much. But the CPU will be interrupted two times the numner of only one printer. So if you get a slow PC it may be affected a bit.

The real issue with the original post is in the 3rd printer hooked up to the parallel port. If you have a 2nd CPU in your PC it will make a huge difference. The 2nd CPU may be totally free from being interrupted. A dual processor system is hard to come by even you visit flea markt frequently. Fortunately Intel will have (or has had) dual core processor for PCs. It looks like one CPU but with 2 core in it. It is effectively a dual processor for a PC.