Abstract: Each transport electrode has its longitudinal direction intersecting with a sub-scanning direction. Transport electrodes 133a are disposed in parallel with each other and are arrayed along the sub-scanning direction. A transport-electrode electricity supply wiring section is connected to root portions of the transport electrodes. The root portions are one end portions of the transport electrodes with respect to the longitudinal direction. Toner transport guide members are disposed in such a manner as to cover the transport-electrode electricity supply wiring section and opposite end portions of the transport electrodes; i.e., the root portions and distal end portions.

Abstract: An image forming apparatus, such as a laser printer, may use high levels of heat to form images, and some elements may expand and contract with changing temperatures. An apparatus may include a heat roller disposed against a pressure roller, with an endless belt member enclosing the pressure roller. The belt member may also have different frictional characteristics on an inside and outside of the roller, such that when peripheral speeds change due to expansion of the pressure roller, the belt member may be configured to slip against the pressure roller, and maintain a frictional relationship with the heat roller (or a printing medium, such as paper, that is pinched between the rollers). Additionally, the rotational speed of an axis of the pressure roller may be adjusted to compensate for the thermal expansion.

Abstract: A fixing device for fixing a developed image of developer onto a recording sheet by heating and fusing the developer includes a heating roller, a pressure roller and a driving force input element. The heating roller is configured to be heated by a heat source, such as a halogen heater. The pressure roller is disposed adjacent to the heating roller, such that a recording sheet is fed and conveyed between the pressure roller and the heating roller. The driving force input element is fixed to the pressure roller for causing the pressure roller to rotate. A diameter Dp of the pressure roller and a nip width N between the heating roller and the pressure roller in circumferential directions thereof have a relationship represented by the following expression: 0.24<N/Dp<0.6.

Abstract: In a fixing portion, a heating roller and a pressure roller are provided. An angle of separation ? (°), the temperature THR (° C.) of the surface of the heating roller, the diameter DPR (mm) of the pressure roller, and the width WNIP (mm) of a nip part are set to satisfy the following inequality: 114?0.55 THR?2.36??1.59 DPR+8.62 WNIP?144.

Abstract: Disclosed is a thermal fixing device using at least two heaters for respectively heating center and end portions of a fixing member, in which after the driving of the two heaters is stopped, thermal fixing can be re-started quickly at proper temperatures for both the center and end portions. First, in S100, a judgment is made as to whether the center portion temperature of the thermal roller exceeds 100° C. or not. When it exceeds 100° C., the procedure advances to S110, where the center heater is turned ON two seconds after turning ON the side heater. By thus turning ON the center heater two seconds after the turning ON of the side heater, it is possible to reduce the temperature difference between the two heaters to approximately 8 to 13° C. at the time point when the center heater is turned ON.

Abstract: A temperature sensor for detecting the temperature of a heating roller contacts the heating roller with the bottom surface of a contact section provided on the front end of the temperature sensor. A temperature detecting element is disposed on the upper surface of the front end at a position corresponding to the contact section. The front edge of the sensor is bent away from the heating roller. During a printing process, a portion of the toner that is liquefied in the heat fixing process remains on the heating roller and is subsequently deposited on the bottom surface of the contact plate as the heating roller rotates. However, by forming the surface from the contact section to the front edge as a smooth curved surface to eliminate edges or corners that can lead to the accumulation of toner, a clump of toner does not form on the bottom surface of the contact plate.

Abstract: A thermal fixing device includes: a heating member configured to be in contact with a fixation medium; a first pressing member disposed to face the heating member and applies a force directed toward both sides of the fixation medium in a direction orthogonal to a conveyance direction of the fixation medium by pressing the fixation medium to the heating member; and a second pressing member disposed to face the heating member at a position downstream in the conveyance direction with respect to the first pressing member and applies a force, which is larger than the force of the first pressing member, directed toward both sides of the fixation medium in a direction orthogonal to the conveyance direction.

Abstract: A thermal fixing device is equipped with a plurality of heaters for heating a fixing member at different axial positions thereof for proper temperature control. When the difference between the center temperature TA and the end temperature TB exceeds a proper temperature difference range (15° C.), of the center temperature TA and the end temperature TB, the one nearer to the average temperature Tm of the fixing upper limit temperature Th and the fixing lower limit temperature T1. is selected. The control value for the farther halogen lamp is changed so as to approach the selected temperature. When the temperature difference is 10° C. or less, the control value is further changed. With this process, it is possible to set both the temperatures and the portion near the center of the thermal roller to temperatures within the proper temperature range.

Abstract: In a fixing portion, a heating roller and a pressure roller are provided. An angle of separation ? (°), the temperature THR (° C.) of the surface of the heating roller, the diameter DPR (mm) of the pressure roller, and the width WNIP (mm) of a nip part are set to satisfy the following inequality: 114?0.55 THR?2.36 ??1.59 DPR+8.62 WNIP?144.

Abstract: An image forming includes a plurality of photosensitive bodies and a drive unit. Each photosensitive body forms an image having a different color. The drive unit selectively switches between forward drive and reverse drive. The drive unit uses forward drive to selectively drive a particular one of the plurality of photosensitive bodies and uses reverse drive to selectively drive another one of the plurality of photosensitive bodies.

Abstract: A thermal fixing device includes: a heating member configured to be in contact with a fixation medium; a first pressing member disposed to face the heating member and applies a force directed toward both sides of the fixation medium in a direction orthogonal to a conveyance direction of the fixation medium by pressing the fixation medium to the heating member; and a second pressing member disposed to face the heating member at a position downstream in the conveyance direction with respect to the first pressing member and applies a force, which is larger than the force of the first pressing member, directed toward both sides of the fixation medium in a direction orthogonal to the conveyance direction.

Abstract: A thermal fixing device and an image forming apparatus having a thermal fixing device being capable of executing a fixing operation rapidly for printing mediums of different sizes with a stable fixing temperature at any time without causing a hot offset is provided. In a first halogen lamp A and a second halogen lamp B, thermal density (A1) of a first heat region corresponding to a first region HX that a small size paper 3a contacts and thermal density (B1) of a first heat region BX, and thermal density (A2) of a second heat region AY corresponding to a second region HY that a large size paper 3b contacts and thermal density (B2) of a second heat region BY are set so as to satisfy conditions that A1>A2 and B1<B2, and A1+B1<A2+B2. The second region HY is positioned on two ends of the first region HX. In the fixing operation of a large size paper 3b, the first halogen lamp A is always on and the second halogen lamp B is controlled to be on/off.

Abstract: A temperature sensor for detecting the temperature of a heating roller contacts the heating roller with the bottom surface of a contact section provided on the front end of the temperature sensor. A temperature detecting element is disposed on the upper surface of the front end at a position corresponding to the contact section. The front edge of the sensor is bent away from the heating roller. During a printing process, a portion of the toner that is liquefied in the heat fixing process remains on the heating roller and is subsequently deposited on the bottom surface of the contact plate as the heating roller rotates. However, by forming the surface from the contact section to the front edge as a smooth curved surface to eliminate edges or corners that can lead to the accumulation of toner, a clump of toner does not form on the bottom surface of the contact plate.

Abstract: Disclosed is a thermal fixing device using at least two heaters for respectively heating center and end portions of a fixing member, in which after the driving of the two heaters is stopped, thermal fixing can be re-started quickly at proper temperatures for both the center and end portions. First, in S100, a judgment is made as to whether the center portion temperature of the thermal roller exceeds 100° C. or not. When it exceeds 100° C., the procedure advances to S110, where the center heater is turned ON two seconds after turning ON the side heater. By thus turning ON the center heater two seconds after the turning ON of the side heater, it is possible to reduce the temperature difference between the two heaters to approximately 8 to 13° C. at the time point when the center heater is turned ON.

Abstract: Disclosed is a thermal fixing device equipped with a plurality of heaters for heating a fixing member at different axial positions thereof for proper temperature control. In S300, a judgment is made as to whether the difference between the center temperature TA and the end temperature TB exceeds a proper temperature difference range (15° C.) or not. When the difference exceeds the proper temperature range (S300: YES), the procedure advances to S310, where, of the center temperature TA and the end temperature TE, the one nearer to the average temperature TM of the fixing upper limit temperature Th and the fixing lower limit temperature T1 is selected. Subsequently, in S320, the control value for the farther halogen lamp is changed so as to approach the selected temperature. And, in S330, a judgment is made as to whether the temperature difference is 10° C. or less. When it is not 10° C. or less, the procedure returns to S320 to further change the control value.

Abstract: A thermal fixing device and an image forming apparatus having a thermal fixing device being capable of executing a fixing operation rapidly for printing mediums of different sizes with a stable fixing temperature at any time without causing a hot offset is provided. In a first halogen lamp A and a second halogen lamp B, thermal density (A1) of a first heat region corresponding to a first region HX that a small size paper 3a contacts and thermal density (B1) of a first heat region BX, and thermal density (A2) of a second heat region AY corresponding to a second region HY that a large size paper 3b contacts and thermal density (B2) of a second heat region BY are set so as to satisfy conditions that A1>A2 and B1<B2, and A1+B1<A2+B2. The second region HY is positioned on two ends of the first region HX. In the fixing operation of a large size paper 3b, the first halogen lamp A is always on and the second halogen lamp B is controlled to be on/off.

Abstract: An image forming includes a plurality of photosensitive bodies and a drive unit. Each photosensitive body forms an image having a different color. The drive unit selectively switches between forward drive and reverse drive. The drive unit uses forward drive to selectively drive a particular one of the plurality of photosensitive bodies and uses reverse drive to selectively drive another one of the plurality of photosensitive bodies.