Abstract: To provide an active energy beam-curable ink for screen printing, having at least monomer components and a polymerization initiator, wherein the polymerization initiator has an absorbance in terms of the concentration thereof of 100 or less at 365 nm.

Abstract: A stencil printer of the present invention includes a print drum and a pressing member. After a cut stencil or master has been wrapped around the print drum, the pressing member presses a paper or similar recording medium against the master. As a result, ink fed to the print drum oozes out to the paper and prints a desired image thereon. When the pressing member presses the paper against the master, an electric field is formed between the pressing member and the print drum in the direction in which the ink migrates from the drum to the paper. The printer is capable of adjusting image density without varying a mechanical pressure to act on the drum or varying the print speed.

Abstract: A developing device for an image forming apparatus and capable of maintaining desirable image quality by reducing a change in the charged state of the surface of a developing roller and a change in the amount of charge to deposit on a developer. An insulating layer constitutes the surface of the developing roller and is made of a material more than 50 percent of which constitutes a non-polar high molecule. This prevents a toner from filming the surface of the roller. The insulating layer is implemented by a material substantially the same as the toner in charge series, so that the toner is frictionally charged by a member other than the developing roller. A discharge brush is held in contact with the roller and made of a material substantially identical with the toner in charge series, thereby preventing the toner from being frictionally charged by the brush even when the toner films the roller.

Abstract: A one-component magnetic toner with high resistivity for use in electrophotography for developing latent electrostatic images to visible toner images by contact development, includes a coloring agent, a binder resin, and a magnetic material which contains a bivalent metal and a trivalent iron with the molar ratio of the bivalent metal to the trivalent iron being 1/3 or less.

Abstract: An image forming apparatus capable of preventing a toner from depositing on non-charged part of an image carrier just after the start of an image forming operation even when implemented with a contact reversal development system and a contact charging system. A charge power source assigned to a charging roller feeds a current great enough to prevent toner deposition on the non-charged part of the image carrier to a constant voltage generation circuit which is connected to the image carrier.

Abstract: A developing device for use in an image forming apparatus and having a developing roller, developing sleeve or similar developer carrier for supplying a one-component developer, or toner, to a latent image which is electrostatically formed on an image carrier such as a photoconductive element. A dielectric layer forming part of the developer carrier and closely related to the fluctuation of developing characteristic has a frequency characteristic which is confined in a predetermined range. Hence, the device is operable in a desirable manner by confining the fluctuation of developing characteristic ascribable to that of developing linear speed in a predetermined range without resorting to the actual measurement of a response characteristic of a developer carrier.

Abstract: A developer carrier is used in a dry-type image developing device employing a one-component developer in an electrophotographic copier or an electrostatic recording apparatus. The developer carrier has a resin coating layer including an electrically conductive filler dispersed therein which is made of a material having a volume resistivity of at most 100 .OMEGA.cm. With this arrangement, the range in which the resistance of the surface layer varies under the ambient condition of varying temperature and humidity is small, producing a copy of stable image quality free from a smeared or contaminated background.

Abstract: A developing device including a developing roller which has a resilient support layer and a dielectric layer provided on the support layer and developing an electrostatic latent image formed on a photoconductive drum through the roller by using a single-component developer, i.e. toner. The variation of development characteristics ascribable to the developing roller is suppressed by providing a resilient material which constitutes the support layer with a resistance value less than a predetermined value that is mostly determined by a relationship between the resistance value and the developing time. Further, a method is described for producing a developing roller for the developing device.

Abstract: A developing device includes a developing sleeve driven to rotate for transporting a film of charged developer as carried thereon past a developing station where the film of developer is applied to an electrostatic latent image to have it developed. Also provided is a sponge roller pressed against and driven to rotate in the same rotating direction as that of the developing sleeve, so that the developer is supplied to the developing sleeve at one side of the contact between the developing sleeve and the sponge roller and any residual developer on the developing sleeve is removed at the other side of the contact. Preferably, a desired voltage difference is established between the developing sleeve and the sponge roller. Furthermore, the sponge roller is preferably so structured to have a sufficient conductivity level at least at its outer peripheral surface thereby allowing the residual charge on the developing sleeve to be discharged sufficiently.

Abstract: An electrostatic latent image developing apparatus supplies toner to a latent image carrier such as a drum-shaped photosensitive body to visualize a latent image formed thereon. The toner is supplied by a rotating drum-shaped toner carrier having a portion confronting the photosensitive body adjacent thereto and another portion held in contact with toner contained in a toner container. The toner is electrostatically attracted to the toner carrier and transferred therefrom to the photosensitive body. The toner on the toner carrier is regulated into a thin toner layer by a toner layer regulating member that is resiliently held in sliding contact with the toner carrier. To prevent toner deposits from being attached to the toner layer regulating member, the toner layer regulating member is made of a material adapted to wear with the attached toner.

Abstract: A developing apparatus is disclosed, in which a developing roller composed of an insulating layer, a dielectric layer and an electrically conductive substrate is made in contact with a photosensitive member to develope a latent image on the member. The dielectric layer is formed of a material whose resistivity-specific dielectricity characteristics satisfies a certain condition which is suitable for medial tone development or binary tone development.