The deal was concluded earlier this month and Danilo chairman Laurence Prince has set the target of doubling PCI's turnover in the first two years.
He told PrintWeek: "The deal benefits both companies, but particularly PCI. Danilo has a lot of buying power so we will be able to lower the cost base for their customers it will help them greatly."
Danilo works with a lot of high-street retailers and Prince said that, as part of the investment the companies would look to offer their customers more exclusive designs, as well as pushing its online calendar ordering service personalise.com.
East London-based PCI will keep its own identity and form part of a £12m-turnover group, with six employees moving as part of the purchase.
Prince also said that there were already plans to invest in PCI in the near future.
He added: "There are not many companies out there being bullish in this way during a recession."