Town have been thwarted in an attempt to take Everton striker Duncan Ferguson on loan. Royle has already added Alan Mahon and Chris Bart-Williams to his squad on a short-term basis this week.
Royle told the club site: "We have made a serious attempt to bring Duncan to Portman Road.
"I feel he is a big impact player who could have made a statement here and I am disappointed that our efforts have been turned down.
"I have been speaking to David Moyes but I understand the reasons why he has declined our request."
Ferguson is not currently a first choice at Goodison Park with Wayne Rooney, Tomasz Radzinski, Francis Jeffers and James McFadden all other options up front for the Toffees.
The striker is well-known to Joe Royle having played in the 1995 Everton FA Cup-winning side.