Screenprint Plus, a division of the SPP Group, has gone into administration putting the jobs of up to 170 staff at risk.
Administrators Andrew McTear and Chris Williams of McTear Williams & Wood were appointed to the Norfolk-based company on 17 April.
According to Screenprint Plus's latest accounts, dated 31 March 2007, it employed 170 staff and had a turnover of £10.8m and a pre-tax profit of £338,000.
Unite national officer Ann Field said: "It's very disturbing that this could happen to a printer of this size, especially a screen printer."
Screenprint operates out of SPP Group's 4,300m2 factory in Great Yarmouth, which also houses the group's SPP Digital and Cherry Cube brands.
Both SPP Digital and Cherry Cube are understood to be unaffected by Screenprint Plus's fall into administration.
However, SPP Engineering, the group's sheet metal engineering division in Nottingham, has also been placed in administration with McTear Williams & Wood.
The company and administrators were both unavailable for comment at the time of writing.