Abstract: A sample handling unit for centrifugation apparatus, especially for cytocentrifugation to produce cell monolayers is disclosed. The sample handling unit is adapted for automated protective processing, e.g. fixation, of matter deposited on a slide during the centrifugation operation. For this purpose the unit has a body defining a deposition chamber, and a treatment fluid reservoir communicating with the deposition chamber via a buffer chamber and a flow path including a weir so arranged that in the position for centrifugation, treatment fluid such as fixative placed in the reservoir is retained therein until centrifugation produces an artificial gravitational field that causes the fluid to flow to the buffer chamber in which it is then retained by the weir for so long as the artificial gravitational field is maintained. Upon decay of that field the fluid flows over the weir towards the deposition chamber.

Abstract: Centrifugation apparatus characterized by a carrier including both a bucket to accommodate a sample chamber and means for supporting a specimen container adjacent to the sample chamber so that material in the specimen container can be pre-centrifuged and then transferred to the sample chamber for centrifugation therein, using automated transfer means. The apparatus may include a disaggregator cooperable with the specimen container to disperse the contents of the latter prior to pre-centrifugation. The transfer means may be a pipette with arrangements for both external and internal flushing and measured dilution of a transferred sample. There may also be means for supplying treatment fluid to a reservoir of the sample chamber.

Abstract: Centrifugation apparatus comprising a sample chamber, a deposit-receiving surface such as a slide and a filter card having an aperture adapted to define on that surface a deposition area communicating with the sample chamber is characterized by the feature that liquid flow paths in the filter card from the perimeter of the aperture are selectively restricted in cross section so as to promote constant velocity flow of liquid, from the sample chamber into the card, in directions substantially normal to all points on the periphery of the aperture. This promotes uniform deposition of solids on the deposit-receiving surface throughout the deposition area, to facilitate inspection of the deposit and, particularly, automated optical scanning of the deposit. The cross sectional restrictions may be accomplished by local removal of filter card material; by local compression of the filter card; or by local impregnation of the card material with an occlusive agent.

Abstract: This invention is concerned with the high speed printing of a line of text on a sheet in very accurate registration with an edge of the sheet or another feature (for example an existing print line) on the sheet. The sheet is fed without preregistration on to a track (10, FIG. 1) which passes the printing station (20). A detector (16) adjacent the track senses the arrival of the edge or some other feature of the sheet and a printing control means (14) responsive to the detector signal initiates the firing of the printing hammer (22) when the print line reaches the printing station, a registered operation being thereby effected without stopping the sheet. The detector signal may start the operation of a counter (70, FIG.

Abstract: To print on each of a number of sheets, the sheets are advanced, preferably in underlapped form, up to registering stops. When a sheet has been registered at the stops, suction is applied to an underlying conveyor, the stops are withdrawn and the sheet is advanced in steps to a printing station, the sheet being held in register by suction during this advancement. Printing takes place while the sheet is stationary and still held in register, between steps of movement. Suction may be switched on and off at the registering station by means of a movable perforated switch plate, the perforations of which are aligned, in a first position of the switch plate, with suction-conveying perforations in another plate or belt; in a second position of the switch plate its perforations are misaligned with the perforations in the other plate or belt, preventing the application of suction to an overlying sheet.