CHICAGO—  Chatham Asset has up their bid to buy R.R. Donnelley to $9.10 a share in cash, an offer it said improves upon bid from Atlas Holdings. Chatham also sueing R.R. Donnelley and Atlas in a Delaware court, asking the court to block some features of R.R. Donnelley's agreement with Atlas, which Chatham said was designed to exclude Chatham's participation in a bid process. R.R. Donnelley had agreed to sell itself to Atlas earlier for $8.52 a share. That deal followed  a previous bid from Chatham, which already owns a portion of R.R. Donnelley's shares and is its largest bondholder. Chatham, the largest investor in RR Donnelley with a 14.9% stake . Chatham, had earlier tried to engage with the company by asking it to replace directors and threatening a proxy war. RR Donnelly is Canada's fifth largest printer according to Graphic Monthly's listing  of Canada's top  printers with sales around $250 million in Canada . RR Donnelly took over Moore Business Forms and all Canadian plants .