Sharp Kabushiki Kaisha Corporation

Tetsunori Mitsuoka

Toshiaki Kagawa

Hiroshi Kida

Takashi Yamanaka

Hiroyuki Kageyama

Akihiko Taniguchi

Atsushi Tanaka

Toyoaki Nanba

Yoshinobu Tateishi

Atsushi Ide

Taisuke Kamimura

Atsushi Inoue

Hiroaki Hori

Kazuhiko Furukawa

Keiji Yasuda

A fixing device includes a fixing roller and a pressure roller provided in a rotatable manner, a heat source for heating the fixing roller, and a controller for controlling AC power supplied to the heat source. The fixing device fixes an unfixed image on a sheet held and conveyed by the fixing roller and the pressure roller. The controller causes a current to flow including current-carrying waveforms having different phase angles in half-wave units during preset control cycles.

Fixing device and image forming apparatus

A fixing device in an image forming apparatus includes a partition member providing a partition between a pressure roller and a housing. The partition member is disposed against the pressure roller along a rotation-axis direction X of the pressure roller. The partition member has a first side face against the pressure roller. The first side face is provided with a thermal insulation member thereon. The thermal insulation member is separated from the pressure roller by a prescribed distance.

A fixing device includes: a plurality of laser irradiation sections each of which emits a laser beam whose wavelength exhibits an absorbance of 80% or more with respect to a corresponding toner; and a control device for controlling the plurality of irradiation sections so that in order to fuse a black toner, (i) a laser irradiation section corresponding to the black toner among the plurality of laser irradiation sections irradiates the black toner with a laser beam thereof, and (ii) the other laser irradiation sections irradiate the black toner with laser beams thereof, where the other laser irradiation sections do not correspond to the black toner among the plurality of laser irradiation sections. Therefore, it is possible to provide a laser fixing device which can fix a color toner while preventing an increase in size of the fixing device as much as possible.

Laser fixing device and image forming apparatus

First, a first temperature difference and a second temperature difference are calculated. The first temperature difference is a difference between (a) a first detected temperature that is a current temperature of the fixing member and (b) a difference of a control target temperature for the fixing member. The second temperature difference is a difference between (a) the first detected temperature and (b) a past temperature of the fixing member which past temperature was detected a predetermined time earlier than the current time. Then, by reading out, from a table prepared in advance, an amount of power to be supplied to a heating member which amount corresponds to a combination of the first temperature difference and the second temperature difference, the amount of power to be supplied to the heating member is determined. In accordance with this amount of power determined, an actual amount of power supplied to the heating member is controlled. This makes it possible to simply and effectively suppress a temperature ripple of the fixing member.

Fixing device, image forming apparatus, and temperature control method for fixing device

A fixing device of belt fixing type is provided. A fixing device includes a connector to be connected to wires provided therein. The connector includes integrally primary-side wiring connector terminals to be connected to primary-side wires each leading to a heat generating resistor, and secondary-side wiring connector terminals to be connected to secondary-side wires including wires each leading to a heat generating element-side thermistor, the secondary-side wires flowing current smaller than the primary-side wires.

Fixing device, image forming apparatus, and method of connecting wires in fixing device

A defective laser element detector gives a fault detection of every laser element in each laser array. A controller determines whether the fault can be compensated for by the other laser elements, taking into account the arrangement, variation and other factors of available laser elements. If it is determined that the fault can be compensated, the controller increases the power of other laser elements individually based on comprehensive evaluation from the parameters such as irradiation areas, amounts of irradiation, irradiation timing and the like of the other adjacent laser elements in the same array including the fault and in the other arrays, so as to compensate the area of irradiation to be irradiated by the defective laser element as a whole.

Laser fixing device and image forming apparatus including the laser fixing device

A fixing device of belt fixing type is provided. A heat generating member that is a heat generating source for heating a fixing belt has a heat generating layer composed of a resistance heat generating element that generates heat due to being energized. The resistance heat generating element includes a paper passing region heating section and a detecting section provided on an end portion in an axial direction of the heat generating member and electrically connected in parallel with the paper passing region heating section. Furthermore, in a vicinity of the detecting section, an overheat preventing element that suppresses energization to the resistance heat generating element when temperature of the detecting section reaches a predetermined value, is provided.

Fixing device and image forming apparatus including fixing device

A fixing device is provided. In a fixing device, a heating member that heats a fixing belt includes a heat generating member that has a heat generating layer that generates heat due to being energized, and a heat radiating member. In the heat radiating member, a heat receiving piece of a first heat radiating section and a heat receiving piece of a second heat radiating section are combined with each other to form a heat receiving section, and a heat transfer piece of the first heat radiating section and a heat transfer piece of the second heat radiating section are combined with each other to form a heat transfer section. Heat pipes that are meandering capillary tube heat pipes are formed inside the first heat radiating section and the second heat radiating section.

The present invention carries out temperature detection and temperature control accurately in a temperature control device using a noncontact-type temperature detecting section. The temperature control device obtains the surface temperature of a fixing roller by using a temperature correspondence table in which correspondences between output voltage values of a main NTC thermistor which detects heat generated by infrared radiation from the fixing roller and the surface temperatures of the fixing roller are shown for respective output voltage values of a compensation NTC thermistor. Here, the output voltage values of the main NTC thermistor and the output voltage values of the compensation NTC thermistor are set in the temperature correspondence table so that an interval between adjacent values of the compensation temperatures corresponding to the output voltage values of the compensation NTC thermistor is smaller than an interval between adjacent values of the surface temperatures of the fixing roller which temperatures correspond to the output values of the main NTC thermistor.

Temperature control device, temperature control method, fixing device, image forming apparatus, temperature control program, computer-readable recording medium, and computer data signal

A control section () includes a first power control section () (a first power control mode) and a second power control section () (a second power control mode). The first power control section () is for controlling an setting value of electric power to be supplied to a heater lamp () based on the temperature of a heating roller (). The second power control section () is for controlling the setting value of electric power to be supplied to the heater lamp () in order to forced-drive the heater lamp () by an electric power that is higher than the setting value of electric power. Switching control means () performs switching between the first power control mode and the second power control mode depending on a status of operation of each of components forming an image forming apparatus ().

Power control method for controlling a setting value of electric power to be supplied to each of components of an apparatus by switching between power control modes depending on a status of operation of each of the components of the apparatus

A fuser unit including: a set of a heat roller and a pressure roller for sandwiching and conveying a printing sheet while heating the printing sheet by the heat roller; a peripheral surface contact member which is in contact with the peripheral surface of the heat roller; an external heater for heating the peripheral surface contact member by applying electric energy; a contact member temperature sensor for detecting a temperature of the peripheral surface contact member; and a temperature controller for controlling an upper limit temperature of the peripheral surface contact member in accordance with the number of printing sheets conveyed per unit time.

Fuser unit and imaging forming apparatus having the same

A fixing device () includes a fixing roller () which is in contact with an unfixed image formed on a printing medium () with toner () and a pressure roller () which is in contact with the fixing roller (). The fixing device () causes the fixing roller () and the pressure roller () to sandwich and feed the printing medium (), so as to fix the unfixed image onto the printing medium (). The fixing device () gives a holding electric field which is an electric field in a direction for holding a reverse polarity toner () on the printing medium (). The reverse polarity toner () has a polarity opposite to that of the toner () which forms an image on the printing medium. Thus, it is possible to avoid a troulile caused by the adhesion of the reverse polarity toner () to the pressure roller (). Therefore, it is possible to avoid an image failure caused by the reverse polarity toner, maintain a normal image forming operation, and secure a satisfactory image quality and the life of each means even in long-term use.

Fixing method, fixing device, and image forming apparatus

A fixing device () of the present invention includes a fixing roller () contacting a toner image surface, and a pressure roller () contacting a surface opposite to the toner image surface. In the fixing device (), a printing sheet (P) on which unfixed toner image is formed passes through a fixing nip portion (Y) where the fixing roller () and the pressure roller () are in contact with each other, so that the above-described toner image is fixed on the printing sheet (P). The fixing device () further includes a control circuit () which controls heater lamps (to) so that a surface temperature of the pressure roller () is in a temperature range defined by a cold offset occurring boundary temperature (Thc) of the fixing roller () and/or a hot offset occurring boundary temperature (Thh) of the fixing roller (). With this, it is possible to suppress or prevent a transfer of toner to a pair of rollers (a transfer from the back of the printing sheet to the pressure roller, a transfer from the pressure roller to the fixing roller).

Fixing device and fixing method and image forming device

A fusing device () has heat reflectors () and () positioned in consideration of the fact that convective heat loss from respective outer surfaces of the heat reflectors () and () depends on orientation of the outer surfaces. More specifically, each of the heat reflectors () and () are positioned so as to have a convective heat transfer coefficient &#x3b7; of up to 0.9. The convective heat transfer coefficient &#x3b7; is given by the following expression:&#x3b7;=(0.770.54)/(),were Su is a projected area of an outer surface of each of the heat reflectors on an upper horizontal plane, Sh is a projected area of the same on a vertical plane, and Sd is a projected area of the same on a lower horizontal plane.

Heating device

A fixer (heater) includes a heat roller and a pressure roller pressing each other. The fixer heats a heated material by passing the heated material through a press region where the heat roller and the pressure roller meet. The fixer further includes an external heat roller heating the pressure roller from outside the pressure roller. A transit time taken for any given point on the heated material to pass through the press region is less than or equal to 2.3&#xd7;10sec. The surface temperature, T(&#xb0; C.), of the heat roller and the surface temperature, T(&#xb0; C.), of the pressure roller satisfy T&#x2212;T&#x2266;100 (&#xb0; C.), and preferably satisfy T&#x2212;T&#x2266;70 (&#xb0; C.). The load on the heat roller is reduced, and so is the power consumption.

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Osaka, Japan

Tetsunori Mitsuoka