Is it OK to ask prosperous client to invest in our startup company?

We are an early start up (7 months old), and we are in talks with 3 - 4 clients. We are building an E-learning kind of tool and looking for building the content as well.

I kind of sensed one client may be willing to invest in our company if asked (my gut feeling only). We are in a stage where we are in talks with this particular client who is very excited about our product - however, they are not yet ready to test/buy the product. So I was wondering if we can get the investment from this institute then we can achieve lot of things and faster. But I am not sure whether to ask them or not, and could it lead to some other problem like they might not buy your product at all, etc.

So I need suggestions on how to go about this? And if I can ask them, what is the best approach and when?

I would say that you should only ask for payment from this company (NOT investment, that might be an embranglement) for the opportunity to be the first institute that gets to test your product. Think of it more like an advance rather than an investment.

That means that they need to be willing to test and buy your product. If they're not, then it's a wash - you're not going to get investment money from them.

So, turn around and offer the opportunity for another company to be your beta tester and one of the first to get your product!

Customers who use your app and want to invest in your app is a big boost to your start up and when you go to investors and say that your customers invested in your app they may get an idea about how good the product is and also how imp the product is.

Go a head and ask them if they want to invest in your company