Abstract: A belt type fixing device of the present invention includes a fix roller, a press roller rotatable in pressing contact with the fix roller, a heat roller accommodating a heat source therein and a belt passed over the fix roller and heat roller. A non-contact type temperature sensor is positioned in a sheet passing range corresponding to the width of a minimum sheet size and assigned to the heat roller while a contact type temperature sensor is positioned outside of the sheet passing range. A controller prevents the heat source from being turned on if temperature sensed by the non-contact type temperature sensor is short of preselected temperature B when temperature sensed by the contact type temperature sensor reaches preselected temperature A assigned to the non-contact type temperature sensor. A reflection type sheet sensor determines whether or not a sheet is present on the belt.

Abstract: An image forming apparatus includes a first heater that heats a heating member, a second heater that heats a support member, and a third heater that heats a facing member. The image forming apparatus further includes a fixing belt wound around between the heating member and the support member, and a facing member arranged so as to face the fixing belt. A paper is passed through a nip portion between the facing member and the fixing belt and a toner image is fixed on the paper by applying heat and pressure to the toner of the toner image. Only the first heater is energized during the fixing operation. All the three heaters are energized at the time of startup operation and during a standby state.

Abstract: An image forming apparatus includes a first heater that heats a heating member, a second heater that heats a support member, and a third heater that heats a facing member. The image forming apparatus further includes a fixing belt wound around between the heating member and the support member, and a facing member arranged so as to face the fixing belt. A paper is passed through a nip portion between the facing member and the fixing belt and a toner image is fixed on the paper by applying heat and pressure to the toner of the toner image. Only the first heater is energized during the fixing operation. All the three heaters are energized at the time of startup operation and during a standby state.

Abstract: A fixing device of the present invention includes a fixing roller 50, a press roller 70, a heat roller 60 provided with a heat source therein, and a fixing belt passed over the fixing roller and heat roller. At least one of the fixing roller 50 and press roller 70 is also provided with a heat source therein. At the time of warm-up of the fixing device, a controller causes the fixing belt to turn while causing at least one of the heat sources to generate heat. After the surface of the fixing belt has risen to a preselected warm-up temperature, the controller allows a sheet path or a printing to be executed. When a sheet path is not executed, the controller causes the fixing belt to turn for a preselected period of time after interrupting the generation of heat.

Abstract: A belt fixing unit, an image forming apparatus, and a toner material are disclosed capable of obviating undesirable fixing belt deformation and low image quality. The belt fixing unit includes a fixing roller, a heating roller, a fixing belt, and a pressing roller in contact with the fixing roller to form a fixing nip having the fixing belt intervening there between, the fixing belt including at least a base member formed of a heat-resisting resin having a thickness of 90 ?m or smaller and acted upon by a tensile force of 0.49 N/mm or less. The toner is a low-melting point toner formed by subjecting a toner preparatory solution containing at least a prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant and a releasing agent dispersed in an organic solvent to extension and/or crosslinking reactions in an aqueous medium.

Abstract: A fixing device including a rotation body and a facing unit configured to face the rotation body. The fixing device also includes a first heat unit configured to heat a nipping area that is formed between the rotation body and the facing unit. A second heat unit is also provided to heat the nipping area. The fixing device further includes a high heat capacity unit configured to transfer the heat from the first heat unit to the nipping area and a low heat capacity unit configured to transfer the heat from the second heat unit to the nipping area. A heat quantity controller is configured to control heat quantity of the first heat unit and the second heat unit. The first heat unit is also configured to heat the nipping area such that the heat quantity per unit area in edge portions of the nipping area is higher than the heat quantity per unit area of the center portion of the nipping area.

Abstract: An image forming apparatus of the present invention includes an intermediate image transfer belt to which a toner image is to be transferred from an image carrier, an image transferring device for transferring the toner image from the intermediate image transfer belt to a sheet, and a fixing device for fixing the toner image on the sheet. When the length of the sheet in the direction of conveyance is smaller than a distance between the image transferring device and the fixing device, a matching circuit varies only the speeds of the image transferring device and fixing device, but does not vary the speed of a device that executes a step preceding the image transfer step. The matching device then sets an interval between consecutive sheets matching with the varied speeds of the image transferring device and fixing device, thereby matching opposite sides with respect to the image transfer step to each other as to the number of sheets to be conveyed.

Abstract: An image forming apparatus of the present invention includes a paper sensor disposed in a fixing device downstream of a fixing roller pair in a direction of paper conveyance. When a jam occurs in the fixing device without the paper sensor sensing a paper sheet and if the fixing device is not pulled out of the apparatus body, it is determined that a paper left in the fixing device has not been removed. The apparatus is then inhibited from resuming its operation with a jam status being maintained.

Abstract: An image forming apparatus of the present invention disclosed is of the type sequentially transferring toner images from a plurality of photoconductive drums to a sheet being conveyed by an image transfer belt or an intermediate image transfer belt one above the other with bias applying members to thereby form a composite color image. Backup rollers, contacting the inside surface of the belt, each have volumetric resistivity of 109 &OHgr;·cm or above and ten-point mean surface roughness Rz of 6 &mgr;m or above.

Abstract: An image forming apparatus of the present invention includes a paper sensor disposed in a fixing device downstream of a fixing roller pair in a direction of paper conveyance. When a jam occurs in the fixing device without the paper sensor sensing a paper sheet and if the fixing device is not pulled out of the apparatus body, it is determined that a paper left in the fixing device has not been removed. The apparatus is then inhibited from resuming its operation with a jam status being maintained.

Abstract: An image forming apparatus includes a first heater that heats a heating member, a second heater that heats a support member, and a third heater that heats a facing member. The image forming apparatus further includes a fixing belt wound around between the heating member and the support member, and a facing member arranged so as to face the fixing belt. A paper is passed through a nip portion between the facing member and the fixing belt and a toner image is fixed on the paper by applying heat and pressure to the toner of the toner image. Only the first heater is energized during the fixing operation. All the three heaters are energized at the time of startup operation and during a standby state.

Abstract: An image forming apparatus of the present invention includes an intermediate image transfer belt to which a toner image is to be transferred from an image carrier, an image transferring device for transferring the toner image from the intermediate image transfer belt to a sheet, and a fixing device for fixing the toner image on the sheet. When the length of the sheet in the direction of conveyance is smaller than a distance between the image transferring device and the fixing device, a matching circuit varies only the speeds of the image transferring device and fixing device, but does not vary the speed of a device that executes a step preceding the image transfer step. The matching device then sets an interval between consecutive sheets matching with the varied speeds of the image transferring device and fixing device, thereby matching opposite sides with respect to the image transfer step to each other as to the number of sheets to be conveyed.

Abstract: An image forming apparatus of the present invention includes two temperature sensors each being responsive to the surface temperature of a particular portion of a fixing member. A reference temperature setting section sets a reference temperature value on the basis of the temperatures that are sensed by the two temperature sensors when the surface of the heating member is heated to a preselected temperature by a heat source. A controller calculates an actual temperature value on the basis of the temperatures sensed by the temperature sensors. The controller then compares the actual temperature value and reference temperature value to thereby determine whether or not a jam ascribable to a recording medium wrapped around the fixing member has occurred. The controller interrupts current supply to the heat source if such a jam has occurred.

Abstract: An image forming apparatus of the present invention includes two temperature sensors each being responsive to the surface temperature of a particular portion of a fixing member. A reference temperature setting section sets a reference temperature value on the basis of the temperatures that are sensed by the two temperature sensors when the surface of the heating member is heated to a preselected temperature by a heat source. A controller calculates an actual temperature value on the basis of the temperatures sensed by the temperature sensors. The controller then compares the actual temperature value and reference temperature value to thereby determine whether or not a jam ascribable to a recording medium wrapped around the fixing member has occurred. The controller interrupts current supply to the heat source if such a jam has occurred.

Abstract: An image forming apparatus including a fixing unit made up of a heat roller and a press roller and a plurality of sheet feeding devices is disclosed. The apparatus selects an interval between consecutive sheets matching with a sheet transport environment and the kind of sheets without waiting for the end of a sequence of image forming cycles. This allows toner images to be adequately fixed on sheets without regard to the kind of sheets, e.g., ordinary sheets or thick sheets.

Abstract: An image forming apparatus is provided with a web type cleaning device for cleaning a fixing roller of a fixing device. The cleaning device has a web roller having a web wound therearound and a web winding roller to wind the web unwound from the web roller. A part of the web unwound from the web roller is pushed by a pushing device, including a spring member, against the fixing roller with a relatively small pushing force. When the fixing roller rotates, the heating roller is cleaned by the web contacting the heating roller. After a predetermined number of copies are completed and when the heating roller is not rotating, the web is wound by the web winding roller to change the portion contacting the fixing roller.

Abstract: A fixing roller device which is capable of dividing the heating area into a plurality of separately heatable different parts both in the circumferential direction of the heater roller, as well as in the direction parallel to the axis of the heater roller. As a result, the heating area can be varied according to various image fixing requirements, as well as for varying initial warm-up requirements. In addition, the temperature of the heating roller can be controlled by varying the density of heating chips or heating elements which are supplied with power within a heated area. Further, temperature control can also be accomplished utilizing a control arrangement based upon the current passing through the heater chips or heater elements, since the current varies with temperature, and thus external temperature sensors for monitoring the temperature of the fixing roller are not required.

Abstract: A device for detecting the degree of deterioration of bank notes has a driving rotary body and a detection rotary body, which are a pair of oppositely disposed rollers each having alternately disposed enlarged diameter portions and annular grooves. These enlarged portions and the grooves of the two rotary bodies are in staggered, opposed relationship so that when a bank note is conveyed between the two rotary bodies, the note is deformed into a wave shape. The rotation of the driving rotary body influences the rotary movement of the detection rotary body depending on the stiffness of the bank note in the wave shape. When the bank note is new and stiff, the influence is strong, while when the bank note is old and deteriorated with a small stiffness, the influence is small. Such influence is detected from variation in rotary movement of the detection rotary body to which a predetermined rotational characteristic is given by a resistance imparting device.

Abstract: A color printer inludes an ink ribbon supporting frame mounted on a base unit swingingly about an axis parallel to a platen. A ribbon cassette comprises a cassette case for accommodating a color ink ribbon which has a plurality of different color longitudinal stripes so that at least a part of the ink ribbon forms a loop exposed from and extending to the cassette case. The ribbon loop is positioned along the platen and between a printing head and the platen, when the ribbon cassette is set on the ribbon frame. A ribbon guide is slidably mounted on a carrier for supporting the ink ribbon at a position adjacent to the printing head. The ribbon frame and ribbon guide are simultaneously shifted so that a desired one of color stripes of the ink ribbon is positioned on a predetermined printing line.

Abstract: A color printer inludes an ink ribbon supporting frame mounted on a base unit swingingly about an axis parallel to a platen. A ribbon cassette comprises a cassette case for accommodating a color ink ribbon which as a plurality of different color longitudinal stripes so that at least a part of the ink ribbon forms a loop exposed from and extending to the cassette case. The ribbon loop is positioned along the platen and between a printing head and the platen, when the ribbon cassette is set on the ribbon frame. A ribbon guide is slidably mounted on a carrier for supporting the ink ribbon at a position adjacent to the printing head. The ribbon frame and ribbon guide are simultaneously shifted so that a desired one of color stripes of the ink ribbon is positioned on a predetermined printing line.