Abstract: In an image forming apparatus, a developing device operable with toner or single component type developer has a hard first developing roller and a soft second developing roller. Fine magnetic N-S poles are formed on the periphery of the first roller. The second roller conveys the toner, electrostatically transferred thereto from the first roller, to an image carrier. The device frees a toner image from deterioration due to toner particles charged to a polarity opposite to an expected polarity. The toner forms a uniform thin layer on the first roller and is uniformly charged. Toner for use with this type of developing device is also disclosed.

Abstract: In an image forming apparatus, a developing device operable with toner or single component type developer has a hard first developing roller and a soft second developing roller. Fine magnetic N-S poles are formed on the periphery of the first roller. The second roller conveys the toner, electrostatically transferred thereto from the first roller, to an image carrier. The device frees a toner image from deterioration due to toner particles charged to a polarity opposite to an expected polarity. The toner forms a uniform thin layer on the first roller and is uniformly charged. Toner for use with this type of developing device is also disclosed.

Abstract: A developing device which includes a first toner transporting roller, a second toner transporting roller to which toner is transported from the first toner transporting roller and an image bearing member such as a photoconductive drum or belt. Seals are located between the circumferential ends of one of the toner transporting rollers and a bottom portion of a toner hopper. When the seals are between the bottom of toner hopper and the first toner transporting roller, the first toner transporting roller is longer than the second toner transporting roller and the circumferential portions of the first toner transporting roller which contact the seals do not contact the second toner transporting roller.

Abstract: In a developing device for an electrophotographic image forming apparatus, a toner conveyor roller intervenes between a conveyor roller and a developing region where a photoconductive element is located. A toner is electrically transferred from the conveyor roller to the toner conveyor roller and conveyed by the toner conveyor roller to the developing region. This prevents inversely charged toner particles from being brought to the developing region, thereby insuring high quality development.

Abstract: In an image forming apparatus, a developing device has an intermediate developing roller or belt between a developing roller and a photoconductive element. A high-tension power source applies a bias to the intermediate developing roller or belt. The bias before the start of printing is preselected to be zero volts, a voltage opposite in polarity to a charge potential deposited on the photoconductive element, or a voltage identical in polarity with the charge potential and smaller in an absolute value of potential than a potential deposited on the photoconductive element after exposure.

Abstract: In an electrophotographic image forming apparatus of the type using single-ingredient type high resistance toner, a developing roller or similar toner conveyor roller is covered with a dielectric layer which is comparatively thick at opposite end portions than at an intermediate portion. A conductive or semiconductive elastic layer underlies the dielectric layer. With the above configuration, the dielectric layer is prevented from coming off the roller. This, coupled with the tact that the elastic layer does not contact a photoconductive element, eliminates current leaks and thereby extends the life of the roller and photoconductive element.

Abstract: In an image forming apparatus, a developing device of the type developing an electrostatic latent image formed on an image carrier by using single-component type toner has a regulating member for regulating the amount of the toner fed thereto, a first conveying member for conveying the toner regulated by the regulating member and deposited thereon, and a second conveying member for conveying the toner transferred from the first conveying member thereto to the image carrier. The first and second conveying members are each movable at a particular speed in a particular direction. The device is free from problems attributable to oppositely charged toner particles despite the use of the single-component type toner and, in addition, insures attractive images.

Abstract: A developing device for an image forming apparatus and using a single component type developer, i.e., toner, has a developing roller, a doctor blade, and an elastic intermediae roller. The developing roller and intermediate roller contact each other and rotate in the same directions such that they move in opposite directions at the position where they contact each other. The developing roller is provide with a surface roughness of Rz 10 .mu.m or less in terms of ten-point mean value as prescribed by JIS (Japanese Industrial Standards) in order to deposit an adequate charge on toner.

Abstract: A developing device for an image forming apparatus and having a relatively hard first developing roller formed with fine N-S magnetic poles on the periphery thereof, and a relatively soft second developing roller for conveying toner electrostatically transferred thereto from the first roller toward a photoconductive drum. The toner is charged by friction while being passed through between the first roller and a blade, and then magnetically deposited on the first roller. At a position where the first and second rollers contact each other, only the adequately charged toner is electrostatically transferred from the first roller to the second roller. The second roller conveys the toner toward the drum. As a result, the toner is brought to a developing position in an amount corresponding to a saturation or maximum image density. The second roller is made up of a metallic conductive core, a semiconductive foam layer, and an insulative surface layer implemented by resin.

Abstract: A developing device for an image forming apparatus and having a relatively hard first developing roller formed with fine N-S magnetic poles on the periphery thereof, and a relatively soft second developing roller for conveying toner electrostatically transferred thereto from the first roller toward a photoconductive drum. The toner is charged by friction while being passed through between the first roller and a blade, and then magnetically deposited on the first roller. At a position where the first and second rollers contact each other, the adequately charged toner is substantially evenly charged by friction and electrostatically transferred from the first roller to the second roller. The second roller conveys the toner toward the drum. The second roller has a surface roughness whose ratio to the mean particle size of the toner is selected to be less than or equal to 1.5.

Abstract: An electrophotographic apparatus capable of forming a high quality image by a contact type developing system using a photoconductive belt and a developing roller. The belt has a tubular configuration. A single friction roller is made of rubber and received in the tubular belt to drive it in a rotary motion. The friction roller has an outside diameter smaller than the inside diameter of the belt to provide the belt with a slack. The developing roller contacts the slack of the belt and, therefore, contacts the belt over a sufficient nip width.

Abstract: A facsimile apparatus which includes a control part, first and second rolls of first and second recording sheets of different sizes, a platen roller being driven to transport a recording sheet selectively being fed from either the first roll or the second roll, a thermal recording head being provided in contact with the platen roller for carrying out thermal recording, a first feed roller being driven to transport the first recording sheet from the first roll to the platen roller, and a second feed roller being driven to transport the second recording sheet from the second roll to the platen roller.

Abstract: A controller of an image recording apparatus controls an initializing process for adjusting and appropriately positioning tip ends of the set recording sheets by transporting the recording sheets in a reverse direction until tip ends thereof are detected. After the tip end of one recording sheet is detected this recording sheet is transported in a forward direction until the tip end thereof reaches a position on the downstream side of a cutter, and a tip portion of this first recording sheet is cut by the cutter. This recording sheet is then transported in a reverse direction until a cut end of this recording sheet reaches a first predetermined position. After the tip end of the other recording sheet is detected this recording sheet is transported in the forward direction until the tip end thereof reaches a position on the downstream side of the cutter, and a tip portion of this recording sheet is cut by the cutter.