Abstract: A cassette containing a printing head removably installed in an ink jet printing machine. The cassette includes a housing which encloses the printing head in a protective manner when the cassette is removed from the machine and when the cassette is installed in the machine and the printing head is in an inoperative position. The head and housing are provided with locking elememts for securing the head in the housing when the cassette is to be removed.The machine includes a carriage for moving the printing head past a record carrier during printing operations, locking elements for locking the printing head onto the carriage when the cassette is installed in the machine, a receptacle for holding the housing in the machine, and a mechanism for releasing the locking elements when the printing head is in the inoperative position to permit removal of the cassette from the machine.

Abstract: A paper guiding device and operating method for use in an office writing machine, the device including a platen carried by a shaft and constituting a paper support, the platen shaft and platen being rotatable in a first direction for insertion of a paper sheet in the machine and in a second direction opposite to the first direction, a paper holding rail disposed adjacent the platen and carrying a plurality of pressure rollers which are pressed toward the platen, a rocker member supporting the rail and mounted to undergo pivotal movement about the axis of rotation of the platen shaft between a paper insertion position and a normal printing position; and a coupling member coupling the rocker member and platen such that rotation of the platen in the second direction effects pivotal movement of the rocker member into the paper insertion position for insertion of the leading edge of a paper sheet between the rollers and the platen and rotation of the platen in the first direction effects pivotal movement of the ro

Abstract: A device for guiding a record medium sheet which is to be printed upon in a printing machine having a platen, the device being arranged to guide the sheet around the platen and including an apron member formed and positioned to hold the sheet in contact with the platen and to guide the sheet at a point closely below the line being printed, the member being constructed to conform to the curvature of the lower portion of the platen and presenting a press and guide edge at each end of the member in the direction of the circumference of the platen, and a spring biassing component disposed for pressing the member resiliently against the platen to cause the edges to bear against the platen, the member being of a material selected so that the coefficient of friction between the record medium sheet and the press and guide edges is less than the coefficient of friction between the platen and the record medium sheet.

Abstract: A carriage guide for supporting a typing element carrier and composed of two guide rails extending parallel to a printing abutment, and pairs of guide rollers mounted on intersecting axes and connected with the typing element carrier for centering the typing element carrier at at least one of the guide rails, is further provided with first and second roller carriers carrying the guide rollers at sides thereof extending parallel to the rails, the roller carriers being disposed to intersect one another and the second roller carrier being provided with a slide edge, elements defining a common joint extending between, and parallel to, the guide rails and via which the carriers bear against one another, a tensioning spring element acting between the roller carriers, a receiving element carried by the first roller carrier at one of its sides parallel to the rails for establishing an articulated connection with the typing element carrier, and a supporting spring element cooperating with the slide edge for effecting

Abstract: A centrifugal coupling for connecting a driven rotary component with another rotary component has a pair of flyweights mounted on the driven component for pivoting about pivot axes which are so spaced from one another transversely of the axis of rotation of the rotary component that straight lines intersecting the pivot and center of gravity of the respective flyweight will extend parallel to a plane of symmetry passing through the axis of rotation intermediate the flyweights when the coupling is in an operating position in which it centrifugally couples the two components for joint rotation.

Abstract: A tabulator apparatus for a typewriter whose carriage can be manually set to make carriage steps of different length corresponding to the width of types of different exchangeable type carriers. The apparatus includes a manually shiftable transmission connecting the tab carrier and the escapement member with the carriage so that the carriage can move in larger carriage steps relative to the tab carrier.