Xerox Corp said Thursday that net income grew by 15 per cent in the second quarter, but revenue growth was slight because sales from its new digital products have not yet started to kick in. Xerox also said earnings and revenues were hurt by the adverse effect of currency, due to the strengthening dollar, which it said will become even greater in the second half. The giant maker of copiers and other office products said its net income for the three months ended June 30 rose to $337 million, or 94 cents a share, up from from $293 million, or 81 cents a share.