Abstract: The invention is concerned with the problem that with known plastic casting moulds, especially those of polypropylene, the lenses produced with these moulds have a slippery surface. The invention solves this problem through the use of polymers which are notable for their very low oxygen permeability.

Abstract: A method of adhesively bonding an adhesive coated, semi-rigid film to a substrate is reported. The method utilizes at least two alignment tools that are each positioned to substantially contact the surface of a substrate at an outer edge of the substrate. The adhesive-coated, semi-rigid film is then interposed between the first and the second alignment tools and the adhesive is brought into contact with the major surface of the substrate. The semi-rigid film is then aligned by contacting a first side edge of the semi-rigid film with a major surface of a first alignment tool and contacting a second side edge of the semi-rigid film with a major surface of a second alignment tool such that the film is aligned relative to the edge of the substrate. After alignment, pressure is applied to at least a portion of the surface area of the first side of the semi-rigid film to effectuate adhesive bonding of the film to the major surface of the substrate.

Abstract: An apparatus for transferring a plurality of toner images having a charge thereon from a photoconductive member to a receptor sheet, the transferring device including a first corona generator for applying a charge to the sheet of polarity opposite to that of the charge on the corresponding toner image and for transferring the toner image from the member to the sheet, a second corona generator, located after the first corona generator, for applying a charge to the toner image on the sheet of a polarity equal to that of the charge on the toner image for increasing the charge thereof, and a grounding electrode opposite to the second corona generator for electrically grounding the opposite side of the receptor sheet.

Abstract: A system is described for transporting sheet-like material. The sheet has a powder, such as electrographic toner particles, loosely attached to it at one or both sides. The particles may be laid down in an image-wise manner by an electrophotographic or direct electrographic system, such as a printer or a copier. The sheet is transported by an endless belt or by a drum. In order to preserve the location of toner particles on the sheet, and to establish correct transportation of the sheet, electrostatic charges are applied either to the sheet or the transporting member or both. As such, the sheet suitably adheres to the transport system and electrostatically loaded toner particles may even adhere better to the sheet.

Abstract: In an apparatus and method for producing simplex prints in a single pass duplex printer, two sheets are conveyed in coinciding relationship through a common path during a print cycle. While the sheets are simultaneously conveyed through the common path, a first toner image is formed on one side of one sheet and a second toner image is formed on an opposite side of the other sheet. The toner images are simultaneously fixed on both sheets by a separate fixing station.

Abstract: A method for controlling the density of microdots produced by a binary or multilevel electrophotographic device. In one example, the toner concentration in a two-component developing system is modified as to keep the toner charge Q/M approximately constant. The toner charge is indirectly assessed. This allows to achieve consistent output densities, irrespective of the environmental parameters, such as relative humidity and temperature.

Abstract: An improved electrostatographic color printing apparatus includes an exposure unit for forming successive electrostatic latent images on the surface of a recording member in the form of an endless belt, a developing station for sequentially developing the electrostatic latent images to form toner images on the belt, and a transfer zone having electrostatic transfer stations for sequentially transferring the toner images from the belt in superposition onto a receptor sheet fed through the transfer stations while in contact with a belt section therein to produce a multicolour duplex image.

Abstract: An electrostatographic developing device having a developer chamber (26), a toner chamber (21), a dosage reservoir (9) and a developer roller (13) mounted within a rotatable housing (11).

Abstract: An electrostatic developing device comprising feed passages (54, 58) for a two-component developer, a hopper (43) for adding fresh toner to the developer to maintain its concentration at a desired level, and a mixer with a vertical helical mixer screw (63) rotatable in a stationary housing (42) and a sleeve (65) surrounding the screw in the housing, an annular space (69) being left between the sleeve and the housing allowing developer transported upwardly by the mixer screw within the sleeve to return via the annular space to the lower end of the screw and then become circulated upwardly again.

Abstract: A method of controlling an electrophotographic imaging process wherein a two-component developer is mixed and activated to obtain a uniform distribution and triboelectric charging of the toner, by interruption of the process and carrying out extra activation and mixing cycles as a function of image area coverage and/or distribution of the image over the image field.

Abstract: A method for making an image using a direct thermal imaging element, comprising on a support a thermosensitive layer incorporating an organic silver salt and a reducing agent contained in said thermosensitive layer and/or in other optional layers, said imaging element being imagewise heated by means of a thermal head having energisable heating elements, characterised in that the activation of the heating elements is executed line by line with a line duty cycle .DELTA. representing the ratio of activation time to total line time, such that the following equation is satisfiedP.ltoreq.P.sub.max 3.3 W/mm.sup.2 +(9.5 W/mm.sup.2 .times..DELTA.)wherein P.sub.max is the maximal value over all heating elements of the time averaged power density P dissipated by a heating element during a line time.