Petri dish imprinting apparatus

An apparatus for inscribing identifying indicia onto a circumferential wall of a petri dish covered by a cover loosely seated on said wall and having a circumferential skirt partly overhanging said wall, comprising:

• means forming a support surface upon which a bottom of a covered petri dish can rest and along which said petri dish can be shifted;
• imprinting means in the form of a block disposed at a generally fixed location along one side of said support surface and having heatable characters adapted to imprint said wall of said petri dish upon rolling displacement of said wall of said petri dish along said block;
• an endless conveying and pressing band yieldably bearing laterally against said skirt of said cover of said petri dish on the opposite side of said support surface for urging said wall against said block and inducing said wall to roll against said block whereby said wall is thermally embossed with imprints of said characters, said band being provided with a pair of idler rollers disposed on said other side of said support surface along the path of movement of said petri dish and with a drive roller spaced from said pair of idler rollers, said band passing around said drive roller and said idler rollers, and said band further having associated therewith spring means for urging said pair of idler rollers toward said block;
• an abutment positionable to engage said petri dish along said one side of said support surface when no imprint is desired and adapted to allow said band to roll said petri dish along said abutment;
• and
• a holddown element for pressing said petri dish against said support surface at least in the region of said imprinting means, said holddown element comprising a pressing roller bearing upon said cover of said petri dish and mounted on a plate overlying said pair of idler rollers, means for adjusting the height of said plate relative to said support surface, and means for adjustably biasing said plate yieldably downwardly to control the force exerted by said pressing roller of said holddown element against said cover.