You need to get a gd printing machine. Do lot of research & testing on this. There are lot of it out there. Xerox machine can be a gd chose, fantastic result. Look into resolution, thickness of paper handling if you wana print card & also cost per print. You have to source for difference grade of paper too. Get in bulk to get good price, when you get gd price you can get better edge to compete. Digital printing are rather competitive in the market, gd luck!

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All equipment takes a back seat to your target market. You didn't state if you were an established printer or not so I will assume you are new to the industry.
You will really need to spend some time researching you market.
Are their any other printers in the area, are they doing offset only or do they offer digital printing, if they are not and they start will that affect you?
Do you have the ability to get customers. Digital Printing is not a walk in copy shop…it doesn't sell itself. You have to go out and get jobs to run on your machine.
Know your limitations. Digital Printing can't do everything. You will need to know when the job is too big or too small, to complicated or to basic.
These are just some of the things that need to be considered before you jump into the printing market.
I am not trying to be negative. But I have been selling paper to printing companies for over 25 years and have seen lots of business come and go. Its not an easy business to break into.
GL