Abstract: A stalled sheet folding and flattening apparatus for reducing a sheet, stalled between a withdrawable and a fixed component of a cut sheet handling system of a sheet handling machine, into a shape and size suitably enabling reliable removal of the stalled sheet through even a relatively narrow gap between the withdrawable and fixed components of the sheet handling system. The stalled sheet folding and flattening apparatus includes a fixed component of the sheet handling system connected to a frame of the machine and having a first section of a sheet path; a withdrawable component of the sheet handling system mounted to the frame, and having a sheet flattening side defining a relatively narrow gap between a fixed surface within the machine and the withdrawable component, and including a second section of the sheet path adjoining the first section of the sheet path; and a sheet folding device mounted to the fixed component.

Abstract: In a sheet handling machine having a frame, and a cut sheet handling system including a sheet path, a stalled sheet pulling and crushing apparatus for reducing a sheet, stalled across an interface between a withdrawable and a fixed component of a cut sheet handling system into a shape and size suitably enabling reliable removal of the stalled sheet through a relatively narrow gap between the withdrawable and fixed components of the sheet handling system.

Abstract: Antibodies which are specific to a thermostable DNA polymerase can be used to reduce or eliminate the formation of non-specific products in polymerase chain reaction methods. These antibodies and other temperature sensitive inhibitors are effective to inhibit DNA polymerase enzymatic activity at a certain temperature T.sub.1 which is generally below about 85.degree. C. The inhibitors are irreversibly inactivated at temperature T.sub.2 which is generally above about 40.degree. C. T.sub.2 is also greater than T.sub.1. Such inhibitors can be supplied individually or in admixture with the DNA polymerase in a diagnostic test kit suitable for PCR.

Abstract: Antibodies which are specific to a thermostable DNA polymerase can be used to reduce or eliminate the formation of non-specific products in polymerase chain reaction methods. These antibodies and other temperature sensitive inhibitors are effective to inhibit DNA polymerase enzymatic activity at a certain temperature T.sub.1 which is generally below about 85.degree. C. The inhibitors are irreversibly inactivated at temperature T.sub.2 which is generally above about 40.degree. C. T.sub.2 is also greater than T.sub.1. Such inhibitors can be supplied individually or in admixture with the DNA polymerase in a diagnostic test kit suitable for PCR.

Abstract: A method and apparatus for detecting and discriminating a copy sheet in an electronic reprographic printing system has a diffuse reflective sensor disposed adjacent a portion of the path over which the copy sheet moves. The sensor is disposed so that its optical axis intersects the copy sheet where the angle of intersection between the copy sheet and the optical axis remains within a specified range of angles for the maximum length of the copy sheet. A diffuse reflective sensor is also disposed adjacent inlet baffles with its optical axis aligned so that a transparent copy sheet is not detected while an opaque copy sheet is.

Abstract: A sheet feeding and corrugating system, especially for output of image substrate sheets of a reproduction apparatus, wherein the sheets are fed in a normal path through a sheet feeding nip comprising plural spaced sheet feeding rollers. Both feeding and variable corrugating of flimsy or stiff sheets is provided by spherical balls freely mounted in generally vertical ball retainers providing for vertical movement and dual axis rotation against the sheet feeding rollers to define the sheet feeding nip and by additional similar balls (in additional similar ball retainers) intermediately of the feed rollers, which additional balls are unsupported vertically except by bottom-of-travel retainers so that these additional intermediate balls roll gravity-loaded against a sheet being fed through the nip to provide sheet corrugation varying automatically with the stiffness of the sheet, and are freely liftable up to the level of the nip by stiff sheets resisting corrugation.

Abstract: A method and apparatus for manipulating the velocity of a copy sheet in a color reprographic system creates a buckle in the copy sheet to decouple accelerations of the leading edge of the copy sheet from the portion that is in contact with the photoreceptor belt and reduces the buckle on long copy sheets for which the buckle can become large enough that the toner image on the body of the copy sheet can become disrupted by contact with stationary portions of the system. The method and apparatus also accelerates the leading edge of the copy sheet as the trailing edge disengages from the photoreceptor belt to prevent the uncontrolled trailing edge of lightweight copy sheets from contacting stationary portions of the system.

Abstract: A transfer blade apparatus for ironing a sheet against the photoreceptor belt during transfer, and smoothing out deformities which cause deletions is disclosed. The transfer blades include a flexible tip to absorb the impact of the blade as it contacts paper, and a spring load to limit and control the force applied to the sheet. Sensors are also utilized to monitor and adjust the timing of the blades.

Abstract: An apparatus which advances a sheet through a transfer zone and into registration with information developed on a moving member. The sheet is advanced to a position wherein a leading portion thereof is immediately ahead of the transfer zone relative to the forward direction of movement of the moving member and a trailing portion thereof is within the transfer zone. The leading portion of the sheet forms a presentation angle of 7-10 degrees with the horizontal. The trailing portion of the sheet is advanced through the transfer zone at a first velocity and the leading edge of the sheet is advanced in a region immediately ahead of the transfer zone at a second velocity, which is less than the first velocity, so as to create a buckle in the leading portion of the sheet positioned immediately ahead of the transfer zone relative to the forward direction of movement of the moving member.

Abstract: Preformed, water-soluble, acrylamide based copolymers comprising a minor proportion of a comonomer, which comonomer contains a site for a crosslinking reaction with a selected crosslinking agent by a reaction that does not involve a free-radical vinyl addition mechanism, which copolymers have M.sub.w and M.sub.n values within selected ranges, can be conveniently and safely used to prepare electrophoresis gel media in situ.

Abstract: A polyacrylamide type gel medium for electrophoresis is conveniently and safely prepared prior to use by crosslinking a water-soluble copolymer of an acrylamide monomer and at least one comonomer copolymerizable therewith, which comonomer contains an active methylene group that will enter into a crosslinking reaction that does not involve a free radical vinyl addition mechanism.

Abstract: A polyacrylamide type gel medium for electrophoresis is conveniently and safely prepared prior to use from a kit which comprises (1) a water-soluble copolymer of an acrylamide monomer and at least one comonomer copolymerizable therewith, which comonomer contains functional groups that permit crosslinking of said copolymer by a covalent but non-free radical initiated mechanism; and (2) a selected crosslinking agent in a package that separates it from the copolymer. Optionally, additional materials that may be usefully incorporated in the gel may be included in the kit, for example, a selected electrophoresis buffer and a complexing agent, such as SDS.

Abstract: A low-cost finisher that creates stapled books includes a tray that is tilted at an acute angle backward and away from the direction of incoming copy sheets. Copy sheets are fed into and slide down the copy sheet support surface of the tray and against a rear registration wall of the tray under the influence of tampers. Another tamper forces the copy sheets against a side registration guide of the tray to align them in the head of a stapler. Stapled books are transported out of the tray to a catch tray.

Abstract: A dual mode document handling apparatus in which either individual cut sheet documents or computer-form web documents are advanced to an exposure station of a reproducing machine. Successive cut sheet documents are advanced in a first direction to the exposure station. Successive incremental lengths of a computer form web document are moved to the exposure station in a second direction substantially normal to the first direction. The machine operator may select either computer-form web document feeding or cut sheet document feeding.