JP5660475B2 - Fixing device and image forming apparatus using the same - Google Patents

Fixing device and image forming apparatus using the same Download PDF

Info

Publication number
JP5660475B2
JP5660475B2 JP2013168163A JP2013168163A JP5660475B2 JP 5660475 B2 JP5660475 B2 JP 5660475B2 JP 2013168163 A JP2013168163 A JP 2013168163A JP 2013168163 A JP2013168163 A JP 2013168163A JP 5660475 B2 JP5660475 B2 JP 5660475B2
Authority
JP
Japan
Prior art keywords
fixing
fixing member
fixing device
heat
heat supply
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP2013168163A
Other languages
Japanese (ja)
Other versions
JP2013228762A (en
Inventor
坂内　和典
和典 坂内
藤原　秀彦
秀彦 藤原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP2013168163A priority Critical patent/JP5660475B2/en
Publication of JP2013228762A publication Critical patent/JP2013228762A/en
Application granted granted Critical
Publication of JP5660475B2 publication Critical patent/JP5660475B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Fixing For Electrophotography (AREA)

Description

本発明は、加熱溶融性の樹脂等よりなるトナーを用いて記録媒体の面に永久固着像を形成するための加熱定着処理を行う定着装置、及びこれを用いた電子写真方式・静電記録方式等の画像形成装置にするものである。   The present invention relates to a fixing device for performing a heat fixing process for forming a permanently fixed image on the surface of a recording medium using a toner made of a heat-meltable resin or the like, and an electrophotographic system / electrostatic recording system using the same. Or the like.

複写機、プリンタ、ＦＡＸ等に用いられる電子写真方式等の画像形成装置においては、記録媒体上にトナー像を形成し、形成したトナー像を熱と圧力で記録媒体に定着させている。定着方式としては、従来よりローラ定着方式が多く採用されている。ローラ定着方式は、内部に熱源を有する定着ローラと定着ローラに対向配置される加圧ローラとを圧接してニップ部を形成し、このニップ部にトナー像が転写された記録媒体を通して加熱加圧し、トナー像を記録媒体に定着させる。従来のローラ定着方式では、熱容量の大きな定着ローラを加熱する必要があるため、待機時には定着ローラの温度を定着温度よりやや低い一定の温度に保っておき、使用時に直ちに使用可能温度まで立ち上げ、使用者が定着ローラの昇温を待つことがないようにする方式が多く採用されている。つまり、定着装置を使用していないときにもある程度の電力を供給しておかなければならず、それによって余分なエネルギーを消費するようになっている。この待機時の消費電力は、画像形成装置本体で使用される消費電力の大部分を占めている。   2. Description of the Related Art In an electrophotographic image forming apparatus used for a copying machine, a printer, a FAX, or the like, a toner image is formed on a recording medium, and the formed toner image is fixed on the recording medium with heat and pressure. As a fixing method, a roller fixing method has been used more than ever. In the roller fixing method, a fixing roller having a heat source therein and a pressure roller disposed opposite to the fixing roller are pressed against each other to form a nip portion, and heat is applied to the nip portion through a recording medium on which a toner image is transferred. The toner image is fixed on the recording medium. In the conventional roller fixing method, since it is necessary to heat the fixing roller having a large heat capacity, the temperature of the fixing roller is kept at a constant temperature slightly lower than the fixing temperature during standby, and immediately rises to a usable temperature at the time of use. Many methods are employed to prevent the user from waiting for the temperature of the fixing roller to rise. That is, a certain amount of electric power must be supplied even when the fixing device is not used, thereby consuming extra energy. This standby power consumption accounts for most of the power consumption used in the image forming apparatus main body.

一方、近年環境問題が重要となり、複写機やプリンタ等の画像形成装置も省エネ化が進んでいる。そこで、待機時の消費電力を削減するために、待機時には電力を供給せず、画像形成時のみ電力を供給するオンデマンド定着方式が提案されている。オンデマンド定着方式では、定着部材として、従来の肉厚の定着ローラに比べて格段に熱容量が小さい薄肉ローラ、又は薄いベルト状若しくはフィルム状の定着部材を用いることで立ち上げ時間を短くしている。   On the other hand, in recent years, environmental problems have become important, and image forming apparatuses such as copiers and printers have been energy-saving. In order to reduce power consumption during standby, an on-demand fixing method has been proposed in which power is not supplied during standby but is supplied only during image formation. In the on-demand fixing method, the start-up time is shortened by using a thin-walled roller or a thin belt-like or film-like fixing member having a significantly smaller heat capacity than a conventional thick fixing roller. .

例えば、オンデマンド方式の定着装置として、特許文献１では、内蔵する熱源からの輻射光を吸収して発熱する発熱層を有する加熱フィルムからなる定着部材を備えた定着装置が提案されている。発熱層を有するフィルム状の定着部材を用い、従来のローラ定着方式に比べ定着部材の大幅な低熱容量化を図っているため、立ち上げ時間を短くすることができる。また、特許文献２では、ベルト状の定着部材のループ内に配置されるとともに、加圧ローラとの間に定着部材を挟んでニップ部を形成するニップ形成部材として、耐熱弾性部材を用いたものが提案されている。このニップ形成部材は、耐熱弾性部材のニップ形成面が加圧ローラのニップ形成部の形状と略同一となるように円弧状に形成されている。そのため、低い加圧力で広いニップ幅を得ることができ、低温での定着が可能となる。また、加圧力を低くできることから、小径薄肉な加圧ローラを使用することが可能となり、加圧ローラの熱容量を小さくすることができる。よって、定着部材や加圧ローラの加熱に必要な熱量が少なくなり、立ち上げ時間を短くすることができる。特許文献３では、定着部材の温度立ち上げ時に加圧ローラを定着部材から離間させる接離機構を備えることで、加圧ローラ側への熱伝達を防ぎ、定着部材表面の温度立ち上げ時間の短縮を図っている。   For example, as an on-demand type fixing device, Patent Document 1 proposes a fixing device including a fixing member made of a heating film having a heat generating layer that generates heat by absorbing radiation from a built-in heat source. Since a film-like fixing member having a heat generating layer is used and the fixing member is greatly reduced in heat capacity as compared with the conventional roller fixing method, the start-up time can be shortened. Further, in Patent Document 2, a heat-resistant elastic member is used as a nip forming member that is disposed in a loop of a belt-shaped fixing member and forms a nip portion with the fixing member sandwiched between the pressure roller. Has been proposed. The nip forming member is formed in an arc shape so that the nip forming surface of the heat-resistant elastic member is substantially the same as the shape of the nip forming portion of the pressure roller. Therefore, a wide nip width can be obtained with a low pressure, and fixing at a low temperature is possible. Further, since the pressing force can be lowered, it is possible to use a small-diameter and thin pressure roller, and the heat capacity of the pressure roller can be reduced. Therefore, the amount of heat required for heating the fixing member and the pressure roller is reduced, and the start-up time can be shortened. In Patent Document 3, by providing a contact / separation mechanism that separates the pressure roller from the fixing member when the temperature of the fixing member rises, heat transfer to the pressure roller side is prevented, and the temperature rise time on the surface of the fixing member is shortened. I am trying.

しかしながら、オンデマンド方式の定着装置においても、立ち上げ時間の更なる短縮化、及び定着時においても熱効率を向上させてより省エネ化を図ることが望まれているのが実情である。特許文献１では、定着部材に供給された熱がニップ部を介して加圧ローラの方へも伝達可能に構成されているため、定着部材の温度立ち上げ時に温度上昇時間が遅くなると考えられる。また、熱源は定着部材の全体を暖めているため、通常の定着時にはニップ以外の定着部材表面から熱が空中に散逸することにより熱効率が低下すると考えられる。特許文献２では、低熱容量の加圧ローラを用いることで、定着部材の温度立ち上がりが早くなると述べられているが、やはり加圧ローラへの熱伝達が可能であるので、立ち上がり時間の短縮には限界があると考えられる。また、特許文献３では、定着部材の温度立ち上げ時に加圧ローラを定着部材から離間させることで加圧ローラ側への熱伝達を防止しているので、定着部材の温度立ち上げ時間が短くなるが、装置が複雑化し製造コストが上昇してしまう。   However, in the on-demand type fixing device, it is actually desired to further shorten the start-up time and to further save energy by improving the thermal efficiency at the time of fixing. In Patent Document 1, since the heat supplied to the fixing member can be transmitted to the pressure roller through the nip portion, it is considered that the temperature rise time is delayed when the temperature of the fixing member is raised. In addition, since the heat source warms the entire fixing member, it is considered that the heat efficiency is reduced due to heat dissipating from the surface of the fixing member other than the nip into the air during normal fixing. Patent Document 2 states that the use of a low-heat-capacity pressure roller speeds up the temperature rise of the fixing member. However, heat transfer to the pressure roller is also possible. There seems to be a limit. Further, in Patent Document 3, since the heat transfer to the pressure roller side is prevented by separating the pressure roller from the fixing member when the temperature of the fixing member is raised, the time for raising the temperature of the fixing member is shortened. However, the apparatus becomes complicated and the manufacturing cost increases.

本発明は、以上の問題に鑑みなされたものであり、その目的とするところは、簡易な構成で、定着部材の立ち上げ時間を短縮し、且つ定着時の熱効率を向上させることができる定着装置及びこれを用いた画像形成装置を提供することである。   The present invention has been made in view of the above problems, and an object of the present invention is to fix a fixing device capable of shortening the start-up time of a fixing member and improving the thermal efficiency during fixing with a simple configuration. And an image forming apparatus using the same.

上記目的を達成するために、請求項１の発明は、回動可能な定着部材と、該定着部材に圧接してニップ部を形成する加圧部材と、該定着部材に熱を供給する熱供給手段と、該定着部材を回転駆動する駆動手段とを有し、該ニップ部に未定着画像を担持する記録媒体を通過させて定着を行う定着装置において、上記熱供給手段により熱が供給される定着部材の熱供給領域は、上記ニップ部を除き、且つ定着動作時の回転方向上流側端部が該ニップ部から所定距離離れるように定められ、上記駆動手段は、定着動作開始時の該定着部材の温度立ち上げ動作として、該定着部材を定着動作時の回転方向とは逆方向に回転駆動させることを特徴とするものである。
請求項２の発明は、請求項１の定着装置において、上記定着部材の熱供給領域は、該熱供給領域の定着動作時の回転方向上流側端部から上記ニップ部までの距離が、該熱供給領域の定着動作時の回転方向下流側端部から該ニップ部までの距離よりも長くなるように定められていることを特徴とするものである。
請求項３の発明は、請求項１又は２の定着装置において、上記熱供給手段は、上記定着部材の内部に熱源を有し、上記駆動手段は、該定着部材の内周面温度を検出する内周面温度検出手段により検出した温度にも基づき、該定着部材を逆方向に回転駆動させる温度立ち上げ動作から、該定着部材を通紙方向に回転駆動させる定着動作に移行することを特徴とするものである。
請求項４の発明は、請求項１、２又は３の定着装置において、上記駆動手段は、上記定着部材の温度立ち上げ動作として該定着部材を整数周分逆方向に回転駆動させることを特徴とするものである。
請求項５の発明は、請求項１、２、３又は４の定着装置において、上記駆動手段は、上記定着部材の温度立ち上げ動作として、該定着部材を定着動作時の回転速度より遅い回転速度で回転駆動させることを特徴とするものである。
請求項６の発明は、請求項３の定着装置において、上記内周面温度検出手段を上記定着部材の熱供給領域の通紙方向上流側端部近傍に配置することを特徴とするものである。
請求項７の発明は、請求項１、２、３、４、５又は６の定着装置において、上記定着部材の外周面温度を検出する外周面温度検出手段を、上記定着部材の熱供給領域の通紙方向下流側端部近傍に配置することを特徴とするものである。
請求項８の発明は、請求項７の定着装置において、上記熱供給手段は、上記定着部材の温度立ち上げ動作時には熱源に最大電力を供給し、定着動作移行後には上記外周面温度検出手段の検出結果に基づいて熱源に電力供給を行うことを特徴とするものである。
請求項９の発明は、請求項８の定着装置において、上記駆動手段は、上記定着部材の温度立ち上げ動作から定着動作への移行時に該定着部材を停止させる停止時間を設け、上記熱供給手段は、該停止時間中は電力供給を停止することを特徴とするものである。
請求項１０の発明は、請求項１、２、３、４、５、６、７、８又は９の定着装置において、上記熱供給手段は、赤外線を照射する赤外線ヒータと、該赤外線ヒータからの赤外線を反射する反射板とを備え、上記定着部材は赤外線を吸収して発熱する発熱層を備えていることを特徴とするものである。
請求項１１の発明は、記録媒体に未定着画像を形成担持させる作像手段と、記録媒体上の未定着画像を定着させる定着手段とを備える画像形成装置において、上記定着手段として、請求項１、２、３、４、５、６、７、８、９又は１０の定着装置を用いることを特徴とするものである。
本発明において、定着部材の熱供給領域は、定着動作時の回転方向上流側端部がニップ部から所定距離離れている。定着部材の温度立ち上げ動作時には、定着部材の回動に伴って熱供給領域で加熱された定着部材の加熱箇所がニップ部に到達するまで、ニップ部を介した加圧部材への熱伝達を抑制できる。よって、ニップ部を介した加圧部材への熱伝達を抑制する分だけ定着部材の温度立ち上げ時間を短縮することができる。そして、定着部材は、温度立ち上げ動作時と定着動作時とで回転方向が逆方向である。これにより、温度立ち上げ動作時には定着部材の加熱箇所がニップ部に到達するまでの距離を取ることができ、定着動作時には定着部材の加熱箇所がニップ部に直ちに到達するような構成をとることができる。また、定着動作時においても、定着部材の定められた熱供給領域に熱が供給されるため、定着部材の全域を加熱する場合に比べ空気中に散逸する熱量が少なく熱効率がよい。 In order to achieve the above object, the invention of claim 1 is directed to a rotatable fixing member, a pressure member that presses against the fixing member to form a nip portion, and a heat supply that supplies heat to the fixing member. And a fixing device that rotates the fixing member and drives the recording medium carrying an unfixed image through the nip portion. In the fixing device, heat is supplied by the heat supply means. The heat supply area of the fixing member is determined so that the upstream side end in the rotation direction during the fixing operation is separated from the nip by a predetermined distance except for the nip portion, and the driving means is configured to fix the fixing member when the fixing operation starts. The temperature raising operation of the member is characterized in that the fixing member is rotationally driven in the direction opposite to the rotational direction during the fixing operation.
According to a second aspect of the present invention, in the fixing device according to the first aspect, the heat supply area of the fixing member has a distance from the upstream end in the rotation direction during the fixing operation of the heat supply area to the nip portion. It is characterized in that it is determined to be longer than the distance from the downstream end portion in the rotation direction during the fixing operation of the supply region to the nip portion.
According to a third aspect of the present invention, in the fixing device according to the first or second aspect, the heat supply means includes a heat source inside the fixing member, and the driving means detects an inner peripheral surface temperature of the fixing member. Based on the temperature detected by the inner peripheral surface temperature detecting means, the temperature rising operation for rotating the fixing member in the reverse direction shifts to the fixing operation for rotating the fixing member in the paper direction. To do.
According to a fourth aspect of the present invention, in the fixing device according to the first, second, or third aspect, the driving means rotates the fixing member in the reverse direction by an integral number of rounds as a temperature raising operation of the fixing member. To do.
According to a fifth aspect of the present invention, in the fixing device according to the first, second, third, or fourth aspect, the driving means is a rotational speed that is lower than the rotational speed during the fixing operation as the temperature raising operation of the fixing member. And is driven to rotate.
According to a sixth aspect of the present invention, in the fixing device of the third aspect, the inner peripheral surface temperature detecting means is disposed in the vicinity of the upstream end portion in the sheet passing direction of the heat supply area of the fixing member. .
According to a seventh aspect of the invention, in the fixing device of the first, second, third, fourth, fifth or sixth aspect, the outer peripheral surface temperature detecting means for detecting the outer peripheral surface temperature of the fixing member is provided in the heat supply area of the fixing member. It is arranged near the downstream end portion in the sheet passing direction.
According to an eighth aspect of the present invention, in the fixing device according to the seventh aspect, the heat supply means supplies maximum power to the heat source during the temperature raising operation of the fixing member, and after the fixing operation shifts, the outer peripheral surface temperature detection means. Electric power is supplied to the heat source based on the detection result.
According to a ninth aspect of the present invention, in the fixing device according to the eighth aspect, the driving means has a stop time for stopping the fixing member when the temperature of the fixing member is shifted from the temperature raising operation to the fixing operation, and the heat supply means. Is characterized in that the power supply is stopped during the stop time.
A tenth aspect of the present invention is the fixing device according to the first, second, third, fourth, fifth, sixth, seventh, eighth, or ninth aspect, wherein the heat supply means includes an infrared heater that emits infrared rays, and an infrared heater. And the fixing member includes a heat generating layer that generates heat by absorbing the infrared light.
According to an eleventh aspect of the present invention, there is provided an image forming apparatus comprising: an image forming unit that forms and supports an unfixed image on a recording medium; and a fixing unit that fixes an unfixed image on the recording medium. 2, 3, 4, 5, 6, 7, 8, 9, or 10 fixing device is used.
In the present invention, in the heat supply region of the fixing member, the upstream end portion in the rotation direction during the fixing operation is separated from the nip portion by a predetermined distance. During the temperature raising operation of the fixing member, heat is transferred to the pressure member through the nip until the heated portion of the fixing member heated in the heat supply area as the fixing member rotates reaches the nip. Can be suppressed. Therefore, the temperature rise time of the fixing member can be shortened by the amount that suppresses heat transfer to the pressure member via the nip portion. The fixing member rotates in the opposite direction between the temperature raising operation and the fixing operation. Accordingly, it is possible to take a distance until the heated portion of the fixing member reaches the nip portion at the time of the temperature raising operation, and the heated portion of the fixing member immediately reaches the nip portion at the time of the fixing operation. it can. Further, even during the fixing operation, heat is supplied to a predetermined heat supply region of the fixing member, so that the amount of heat dissipated in the air is small and the thermal efficiency is good as compared with the case where the entire area of the fixing member is heated.

上記目的を達成するために、請求項１の発明は、回動可能な定着部材と、該定着部材に圧接してニップ部を形成する回転可能な加圧部材と、該定着部材に熱を供給する熱供給手段と、該加圧部材を回転させる駆動手段とを有し、該定着部材は該加圧部材によって従動回転され、該ニップ部に未定着画像を担持する記録媒体を通過させて定着を行う定着装置において、上記熱供給手段により熱が供給される定着部材の熱供給領域は、上記ニップ部を除き、且つ定着動作時の回転方向上流側端部が該ニップ部から所定距離離れるように定められ、上記駆動手段は、定着動作開始時の該定着部材の温度立ち上げ動作として、該定着部材を定着動作時の回転方向とは逆方向に整数周分回転させることを特徴とするものである。
請求項２の発明は、請求項１の定着装置において、上記定着部材の熱供給領域は、該熱供給領域の定着動作時の回転方向上流側端部から上記ニップ部までの距離が、該熱供給領域の定着動作時の回転方向下流側端部から該ニップ部までの距離よりも長くなるように定められていることを特徴とするものである。
請求項３の発明は、請求項１又は２の定着装置において、上記熱供給手段は、上記定着部材の内部に熱源を有し、上記駆動手段は、該定着部材の内周面温度を検出する内周面温度検出手段により検出した温度にも基づき、該定着部材を逆方向に回転させる温度立ち上げ動作から、該定着部材を通紙方向に回転させる定着動作に移行することを特徴とするものである。
請求項４の発明は、請求項１、２又は３の定着装置において、上記駆動手段は、上記定着部材の温度立ち上げ動作として、該定着部材を定着動作時の回転速度より遅い回転速度で回転させることを特徴とするものである。
請求項５の発明は、請求項３の定着装置において、上記内周面温度検出手段を上記定着部材の熱供給領域の通紙方向上流側端部近傍に配置することを特徴とするものである。
請求項６の発明は、請求項１、２、３、４又は５の定着装置において、上記定着部材の外周面温度を検出する外周面温度検出手段を、上記定着部材の熱供給領域の通紙方向下流側端部近傍に配置することを特徴とするものである。
請求項７の発明は、請求項６の定着装置において、上記熱供給手段は、上記定着部材の温度立ち上げ動作時には熱源に最大電力を供給し、定着動作移行後には上記外周面温度検出手段の検出結果に基づいて熱源に電力供給を行うことを特徴とするものである。
請求項８の発明は、請求項７の定着装置において、上記駆動手段は、上記定着部材の温度立ち上げ動作から定着動作への移行時に該定着部材を停止させる停止時間を設け、上記熱供給手段は、該停止時間中は電力供給を停止することを特徴とするものである。
請求項９の発明は、請求項１、２、３、４、５、６、７又は８の定着装置において、上記熱供給手段は、赤外線を照射する赤外線ヒータと、該赤外線ヒータからの赤外線を反射する反射板とを備え、上記定着部材は赤外線を吸収して発熱する発熱層を備えていることを特徴とするものである。
請求項１０の発明は、記録媒体に未定着画像を形成担持させる作像手段と、記録媒体上の未定着画像を定着させる定着手段とを備える画像形成装置において、上記定着手段として、請求項１、２、３、４、５、６、７、８又は９の定着装置を用いることを特徴とするものである。
本発明において、定着部材の熱供給領域は、定着動作時の回転方向上流側端部がニップ部から所定距離離れている。定着部材の温度立ち上げ動作時には、定着部材の回動に伴って熱供給領域で加熱された定着部材の加熱箇所がニップ部に到達するまで、ニップ部を介した加圧部材への熱伝達を抑制できる。よって、ニップ部を介した加圧部材への熱伝達を抑制する分だけ定着部材の温度立ち上げ時間を短縮することができる。そして、定着部材は、温度立ち上げ動作時と定着動作時とで回転方向が逆方向である。これにより、温度立ち上げ動作時には定着部材の加熱箇所がニップ部に到達するまでの距離を取ることができ、定着動作時には定着部材の加熱箇所がニップ部に直ちに到達するような構成をとることができる。また、定着動作時においても、定着部材の定められた熱供給領域に熱が供給されるため、定着部材の全域を加熱する場合に比べ空気中に散逸する熱量が少なく熱効率がよい。 To achieve the above object, a first aspect of the invention, supply and rotatable fixing member, a rotatable pressure member forming a nip portion in pressure contact with the fixing member, a heat fixing member a heat supply means for, and a driving means for rotating the pressure member, the fixing member is rotated by the pressure member, it is passed through a recording medium carrying an unfixed image to the nip In the fixing device that performs fixing, the heat supply region of the fixing member to which heat is supplied by the heat supply unit excludes the nip portion, and the upstream end portion in the rotation direction during the fixing operation is separated from the nip portion by a predetermined distance. The driving means rotates the fixing member by an integral number of revolutions in the direction opposite to the rotation direction during the fixing operation as the temperature raising operation of the fixing member at the start of the fixing operation. Is.
According to a second aspect of the present invention, in the fixing device according to the first aspect, the heat supply area of the fixing member has a distance from the upstream end in the rotation direction during the fixing operation of the heat supply area to the nip portion. It is characterized in that it is determined to be longer than the distance from the downstream end portion in the rotation direction during the fixing operation of the supply region to the nip portion.
According to a third aspect of the present invention, in the fixing device according to the first or second aspect, the heat supply means includes a heat source inside the fixing member, and the driving means detects an inner peripheral surface temperature of the fixing member. also, based on the detected temperature by the inner circumferential surface temperature detecting means, the temperature raising operation for rotating the fixing member in the opposite direction, and characterized by migrating fixing member to a fixing operation of rotating the paper feeding direction To do.
According to a fourth aspect of the present invention, in the fixing device according to the first, second, or third aspect, the driving unit rotates the fixing member at a rotational speed that is slower than the rotational speed during the fixing operation as the temperature raising operation of the fixing member. It is characterized by making it.
According to a fifth aspect of the present invention, in the fixing device of the third aspect, the inner peripheral surface temperature detecting means is disposed in the vicinity of the upstream end of the heat supply area of the fixing member in the sheet passing direction. .
According to a sixth aspect of the present invention, in the fixing device of the first, second, third, fourth or fifth aspect, the outer peripheral surface temperature detecting means for detecting the outer peripheral surface temperature of the fixing member is a sheet passing through the heat supply area of the fixing member. It arrange | positions in the direction downstream side edge part vicinity.
According to a seventh aspect of the present invention, in the fixing device of the sixth aspect, the heat supply means supplies the maximum power to the heat source during the temperature raising operation of the fixing member, and after the fixing operation shifts, the outer peripheral surface temperature detection means. Electric power is supplied to the heat source based on the detection result.
According to an eighth aspect of the present invention, in the fixing device according to the seventh aspect, the driving means has a stop time for stopping the fixing member when the temperature of the fixing member is shifted from the temperature raising operation to the fixing operation, and the heat supply means. Is characterized in that the power supply is stopped during the stop time.
According to a ninth aspect of the present invention, in the fixing device according to the first, second, third, fourth, fifth, sixth, seventh, or eighth aspect, the heat supply means includes an infrared heater that emits infrared rays, and infrared rays from the infrared heaters. The fixing member is provided with a heat generating layer that generates heat by absorbing infrared rays.
According to a tenth aspect of the present invention, there is provided an image forming apparatus comprising: an image forming unit that forms and supports an unfixed image on a recording medium; and a fixing unit that fixes an unfixed image on the recording medium. 2, 3, 4, 5, 6, 7, 8 or 9 fixing device is used.
In the present invention, in the heat supply region of the fixing member, the upstream end portion in the rotation direction during the fixing operation is separated from the nip portion by a predetermined distance. During the temperature raising operation of the fixing member, heat is transferred to the pressure member through the nip until the heated portion of the fixing member heated in the heat supply area as the fixing member rotates reaches the nip. Can be suppressed. Therefore, the temperature rise time of the fixing member can be shortened by the amount that suppresses heat transfer to the pressure member via the nip portion. The fixing member rotates in the opposite direction between the temperature raising operation and the fixing operation. Accordingly, it is possible to take a distance until the heated portion of the fixing member reaches the nip portion at the time of the temperature raising operation, and the heated portion of the fixing member immediately reaches the nip portion at the time of the fixing operation. it can. Further, even during the fixing operation, heat is supplied to a predetermined heat supply region of the fixing member, so that the amount of heat dissipated in the air is small and the thermal efficiency is good as compared with the case where the entire area of the fixing member is heated.

本実施形態に係るプリンタの構成を示す概略構成図。1 is a schematic configuration diagram illustrating a configuration of a printer according to an embodiment. 同プリンタの定着装置の構成を示す構成図。FIG. 2 is a configuration diagram illustrating a configuration of a fixing device of the printer. 同定着装置の定着部材の構成を示す断面図。FIG. 3 is a cross-sectional view illustrating a configuration of a fixing member of the fixing device. 同定着装置の別の定着部材の構成を示す断面図。FIG. 6 is a cross-sectional view illustrating a configuration of another fixing member of the fixing device. 別の実施形態に係る定着装置の構成を示す構成図。FIG. 6 is a configuration diagram illustrating a configuration of a fixing device according to another embodiment. （ａ）は定着装置の動作タイミングを示すタイミングチャート、（ｂ）は定着部材と加圧ローラの温度変化を示す特性図。(A) is a timing chart showing the operation timing of the fixing device, (b) is a characteristic diagram showing temperature changes of the fixing member and the pressure roller. 同定着装置の構成を示す構成図。FIG. 3 is a configuration diagram illustrating a configuration of the fixing device. 従来の定着装置の構成を示す構成図。FIG. 6 is a configuration diagram illustrating a configuration of a conventional fixing device. 定着部材と加圧ローラの温度変化を示す特性図。FIG. 6 is a characteristic diagram showing temperature changes of the fixing member and the pressure roller.

以下、本発明を電子写真方式の画像形成装置としての直接転写方式タンデム型のレーザプリンタ（以下、「プリンタ」という）に適用した実施形態について説明する。図１は本実施形態に係るプリンタの構成を示す概略構成図である。このプリンタは、イエロー（Ｙ）、マゼンダ（Ｍ）、シアン（Ｃ）、黒（Ｋ）の各色の画像を顕像形成する４組の作像手段たるプロセスユニット１Ｙ、１Ｍ、１Ｃ、１Ｋを備えている。以下、各符号の添字Ｙ、Ｍ、Ｃ、Ｋは、それぞれシアン、マゼンダ、イエロー、黒用の部材であることを示す。この４組のプロセスユニット１Ｙ、１Ｍ、１Ｃ、１Ｋは、記録媒体としての用紙Ｐの移動方向（図中反時計回り方向）における上流側から順に所定の間隔をもって配置されている。このプロセスユニット１Ｙ、１Ｍ、１Ｃ、１Ｋはそれぞれ、図中時計回り方向に回転するドラム状の感光体１１Ｃ、１１Ｍ、１１Ｙ、１１Ｋを備えている。この感光体１１Ｙ、１１Ｍ、１１Ｃ、１１Ｋの周囲にはそれぞれ、各感光体表面を帯電する帯電装置１２Ｙ、１２Ｍ、１２Ｃ、１２Ｋ、各感光体表面に形成される静電潜像を現像してトナー画像を形成する現像装置１３Ｙ、１３Ｍ、１３Ｃ、１３Ｋ、用紙Ｐにトナー画像が転写された後の各感光体表面をクリーニングするクリーニング装置１４Ｙ、１４Ｍ、１４Ｃ、１４Ｋ等を備えている。   Hereinafter, an embodiment in which the present invention is applied to a direct transfer tandem type laser printer (hereinafter referred to as “printer”) as an electrophotographic image forming apparatus will be described. FIG. 1 is a schematic configuration diagram illustrating a configuration of a printer according to the present embodiment. This printer includes process units 1Y, 1M, 1C, and 1K, which are four sets of image forming means for forming an image of each color of yellow (Y), magenta (M), cyan (C), and black (K). ing. Hereinafter, the subscripts Y, M, C, and K of the respective symbols indicate members for cyan, magenta, yellow, and black, respectively. The four process units 1Y, 1M, 1C, and 1K are arranged at predetermined intervals in order from the upstream side in the moving direction (counterclockwise direction in the figure) of the paper P as a recording medium. Each of the process units 1Y, 1M, 1C, and 1K includes drum-shaped photoconductors 11C, 11M, 11Y, and 11K that rotate in the clockwise direction in the drawing. Around the photoreceptors 11Y, 11M, 11C, and 11K, charging devices 12Y, 12M, 12C, and 12K that charge the surfaces of the photoreceptors, and electrostatic latent images formed on the photoreceptor surfaces are developed to toner. Developing devices 13Y, 13M, 13C, and 13K that form images, and cleaning devices 14Y, 14M, 14C, and 14K that clean the surface of each photoconductor after the toner image is transferred to the paper P are provided.

上記プロセスユニット１Ｃ、１Ｍ、１Ｙ、１Ｋの下方には、感光体１１Ｙ、１１Ｍ、１１Ｃ、１１Ｋに形成されたトナー画像を用転Ｐに転写する転写ユニット２を備えている。転写ユニット２では、無端ベルト状の転写搬送ベルト２１が駆動ローラ２２と従動ローラ２３に掛け回され、所定のタイミングで図反時計回り方向に回転駆動しながら、用紙Ｐを担持して各プロセスユニット１の転写位置を通過搬送する。また、転写搬送ベルト２１の内部には、転写位置において転写電荷を付与して各感光体１１Ｃ、１１Ｍ、１１Ｙ、１１Ｋ上のトナー画像を用紙Ｐに転写する転写ローラ２４Ｃ、２４Ｍ、２４Ｙ、２４Ｋが設けられている。   Below the process units 1C, 1M, 1Y, and 1K, there is provided a transfer unit 2 that transfers the toner images formed on the photoreceptors 11Y, 11M, 11C, and 11K to the transfer roller P. In the transfer unit 2, an endless belt-like transfer / conveying belt 21 is wound around a driving roller 22 and a driven roller 23, and the sheet P is carried and supported on each process unit while being rotated counterclockwise at a predetermined timing. 1 passes through the transfer position. In addition, transfer rollers 24C, 24M, 24Y, and 24K that transfer toner images on the photosensitive members 11C, 11M, 11Y, and 11K to the paper P by applying transfer charges at the transfer position are provided inside the transfer conveyance belt 21. Is provided.

上記プロセスユニット１Ｙ、１Ｍ、１Ｃ、１Ｋの上方には、各感光体１１Ｃ、１１Ｍ、１１Ｙ、１１Ｋの一様に帯電された表面に画像情報に応じたレーザ光Ｌを照射して静電潜像を形成する光書込ユニット３を備えている。光書込ユニット３は、図示しないレーザ光源、ポリゴンミラー、ｆ−θレンズ、反射ミラー等を備え、所定の露光位置において画像データに基づき回転駆動されている各感光体１１Ｙ、１１Ｃ、１１Ｋ、１１Ｋの表面にレーザ光Ｌを主走査方向に走査しながら照射する。   Above the process units 1Y, 1M, 1C, and 1K, an electrostatic latent image is formed by irradiating the uniformly charged surfaces of the photoreceptors 11C, 11M, 11Y, and 11K with laser light L corresponding to image information. The optical writing unit 3 is formed. The optical writing unit 3 includes a laser light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like (not shown), and is rotated by each photoconductor 11Y, 11C, 11K, 11K based on image data at a predetermined exposure position. The laser beam L is irradiated while scanning in the main scanning direction.

また、本プリンタの下部には、給紙カセット４が配設されている。この給紙カセット４は、用紙Ｐを複数枚重ねた紙束の状態で収納しており、一番上の用紙Ｐに給紙ローラ４１を押し当てている。給紙ローラ４１が図示しない駆動手段によって回転駆動せしめられると、一番上の用紙Ｐが給紙路に向けて送り出される。この給紙路には、搬送ローラ（図示せず）やレジストローラ対４２が配設されており、給紙路に送り出された用紙Ｐは、搬送ローラ対を経てレジストローラ対４２のローラ間に挟み込まれる。レジストローラ対４２は、ローラ間に用紙Ｐを挟み込むとすぐにローラ対の回転駆動を一旦停止させ、後述するように所定のタイミングでレジストローラ対４２の回転駆動を再開して、用紙Ｐを転写位置に向けて送り出す。   In addition, a paper feed cassette 4 is disposed below the printer. The paper feed cassette 4 stores a plurality of paper sheets P in a stacked state, and a paper feed roller 41 is pressed against the uppermost paper sheet P. When the paper feed roller 41 is driven to rotate by a driving means (not shown), the uppermost paper P is sent out toward the paper feed path. A conveyance roller (not shown) and a registration roller pair 42 are disposed in the paper feed path, and the paper P sent to the paper supply path passes between the rollers of the registration roller pair 42 via the conveyance roller pair. It is caught. As soon as the paper P is sandwiched between the rollers, the registration roller pair 42 temporarily stops the rotational driving of the roller pair, and resumes the rotational driving of the registration roller pair 42 at a predetermined timing to transfer the paper P as described later. Send to the position.

上記プロセスユニット１Ｃ、１Ｍ、１Ｙ、１Ｋ及び上記転写ユニット２の図中左方には、用紙Ｐ上の未定着トナー像の定着を行う定着装置５を備えている。定着装置５は、後述するようにフレーム（筐体）５０内に定着部材５１や定着部材５１に圧接してニップ部を形成する加圧部材たる加圧ローラ５２を備えている。   A fixing device 5 for fixing an unfixed toner image on the paper P is provided on the left side of the process units 1C, 1M, 1Y, 1K and the transfer unit 2 in the drawing. As will be described later, the fixing device 5 includes a fixing member 51 and a pressure roller 52 serving as a pressure member that forms a nip portion in pressure contact with the fixing member 51 in a frame (housing) 50.

以上のように構成されるプリンタにおいて、例えばイエロー用のプロセスユニット０Ｙでは、帯電装置１２Ｙにより一様に帯電された感光体１１Ｙの表面に、光書込ユニット３で変調及び偏向されたレーザ光Ｌが走査されながら照射されて静電潜像が形成される。感光体１１Ｙ上の静電潜像は、現像装置１３Ｙで現像されてシアン色のトナー画像となる。転写搬送ベルト２１上の用紙Ｐが通過する転写位置では、感光体１１Ｙ上のトナー画像が用紙２に転写される。トナー画像が転写された後の感光体１１Ｙの表面は、クリーニング装置１４Ｙでクリーニングされ、図示しない除電手段で除電され、次の静電潜像の形成に備えられる。   In the printer configured as described above, for example, in the process unit 0Y for yellow, the laser light L modulated and deflected by the optical writing unit 3 on the surface of the photoreceptor 11Y uniformly charged by the charging device 12Y. Are scanned to form an electrostatic latent image. The electrostatic latent image on the photoreceptor 11Y is developed by the developing device 13Y to become a cyan toner image. At the transfer position where the paper P on the transfer conveyance belt 21 passes, the toner image on the photoconductor 11Y is transferred to the paper 2. The surface of the photoconductor 11Y after the toner image is transferred is cleaned by a cleaning device 14Y, and is neutralized by a neutralizing unit (not shown) to prepare for the formation of the next electrostatic latent image.

他のプロセスユニット１Ｍ、１Ｃ、１Ｋについても、上述した画像形成行程が用紙Ｐの搬送に同期させて実行される。一方、給紙カセット４から給送された用紙Ｐは、レジストローラ対４２により所定のタイミングで送出されて転写搬送ベルト２１に担持され、各プロセスユニット１Ｃ、１Ｍ、１Ｙ、１Ｋの転写位置を通過するように搬送される。各プロセスユニット１Ｃ、１Ｍ、１Ｙ、１Ｋの各色のトナー画像が転写され４色重ね合わせのカラー画像が形成された用紙Ｐは、定着装置５でトナー画像が定着された後、図示しない排紙トレイ上に排出される。   For the other process units 1M, 1C, and 1K, the above-described image forming process is executed in synchronization with the conveyance of the paper P. On the other hand, the paper P fed from the paper feed cassette 4 is sent at a predetermined timing by the registration roller pair 42 and is carried on the transfer conveyance belt 21 and passes through the transfer positions of the process units 1C, 1M, 1Y, and 1K. To be conveyed. The paper P on which the toner images of the respective colors of the process units 1C, 1M, 1Y, and 1K are transferred to form a four-color superimposed color image is fixed on the paper P after the toner image is fixed by the fixing device 5. Discharged to the top.

以上の作像動作は、４色重ね合わせのフルカラーモードが図示しない操作部で選択された時の動作である。例えば、３色重ね合わせのフルカラーモードが操作部で選択された場合には、Ｋトナー像の形成が省略されてＹ、Ｍ、Ｃ３色のトナー像の重ね合わせによるフルカラー画像が用紙２上に形成される。また白黒画像形成モードが操作部で選択された場合には、Ｋトナー像の形成のみが行われて白黒画像が用紙２上に形成される。   The above-described image forming operation is an operation when the full-color mode for superimposing four colors is selected by an operation unit (not shown). For example, when the three-color superposition full-color mode is selected on the operation unit, the formation of the K toner image is omitted, and a full-color image is formed on the paper 2 by superposing the Y, M, and C three-color toner images. Is done. When the monochrome image forming mode is selected on the operation unit, only the K toner image is formed and a monochrome image is formed on the paper 2.

次に、本発明の特徴部となる定着装置５について説明する。図２は、定着装置構成を示す構成図である。図２に示すように、この定着装置５は、円筒状無端ベルト状の定着部材５１と、定着部材５１に圧接してニップ部を形成する加圧ローラ５２とを備えている。定着部材５１のループ内には、定着部材５１を加熱する熱供給手段たるヒータ５３と、ヒータ５３からの熱線を反射する反射板５４や、加圧ローラ５２との間に定着部材４１を挟んでニップ部を形成する加圧板５５を供えている。また、定着部材５１と加圧ローラ５２との間のニップ部よりも、用紙移動方向上流側には、ニップ部に向けて搬送される用紙Ｐを案内する入口ガイド板５８が配設され、ニップ部よりも用紙移動方向下流側には、ニップ部から送出される用紙Ｐを案内する出口ガイド板５９が配設されている。双方のガイド板５８、５９は、いずれも、定着装置５のフレーム５０に固設されている。   Next, the fixing device 5 serving as a characteristic part of the present invention will be described. FIG. 2 is a configuration diagram illustrating the configuration of the fixing device. As shown in FIG. 2, the fixing device 5 includes a cylindrical endless belt-shaped fixing member 51 and a pressure roller 52 that presses against the fixing member 51 to form a nip portion. In the loop of the fixing member 51, the fixing member 41 is sandwiched between the heater 53, which is a heat supply means for heating the fixing member 51, the reflection plate 54 that reflects the heat rays from the heater 53, and the pressure roller 52. A pressure plate 55 forming a nip portion is provided. In addition, an inlet guide plate 58 for guiding the paper P conveyed toward the nip portion is disposed upstream of the nip portion between the fixing member 51 and the pressure roller 52 in the paper movement direction. An exit guide plate 59 for guiding the paper P fed from the nip portion is disposed on the downstream side in the paper movement direction from the portion. Both guide plates 58 and 59 are fixed to the frame 50 of the fixing device 5.

上記定着部材５１は、薄肉で可撓性を有する定着ベルトから構成される。図３及び図４は、定着部材の構成を示す断面図である。図３に示すように、上記定着部材５１は、ＮｉやＳＵＳフィルム等の金属基体５１ａ上に１００〜３００μｍ前後のシリコンゴム等からなる弾性層５１ｂや、ＰＦＡ（４フッ化エチレンバーフルオロアルキルビニルエーテル共重合体樹脂）、ポリイミド、ポリエーテルイミド、ＰＥＳ（ポリエーテルサルファイド）等からなる離型層（表層）５１ｃを形成している。金属基体５１ａを用いる場合には、金属基体５１ａの裏面に、黒色塗装や黒色ニッケルめっき等の赤外線吸収層５１ｄを設けている。また、図４に示すように、定着部材５１’は、ポリイミド、ポリアミド、フッ素樹脂等の耐熱樹脂からなる樹脂基体５１ｅ上に、１００〜３００μｍ前後のシリコンゴム等からなる弾性層５１ｆや、ＰＦＡ（４フッ化エチレンバーフルオロアルキルビニルエーテル共重合体樹脂）、ポリイミド、ポリエーテルイミド、ＰＥＳ（ポリエーテルサルファイド）等からなる離型層（表層）５１ｇを形成してもよい。白黒用の定着部材５１、５１’としては、上記構成の中からシリコンゴム等の弾性層を省いた構成でもよい。このように構成される定着部材５１、５１’は、従来の熱容量の大きい定着ローラに比べ低熱容量化が図られている。また、上記定着部材５１、５１’のループ内に配置される加圧板５５は、板厚が０．１ｍｍ程度の金属板（又は、セラミックやポリイミド樹脂からなる板材）であって、断面形状が略コの字状に形成され、定着部材５１を介して加圧ローラ５２に当接して所望のニップ部を形成する。 The fixing member 51 is composed of a thin and flexible fixing belt. 3 and 4 are cross-sectional views showing the configuration of the fixing member. As shown in FIG. 3, the fixing member 51 includes an elastic layer 51b made of silicon rubber of about 100 to 300 μm on a metal substrate 51a such as Ni or SUS film, PFA (tetrafluoroethylene bar fluoroalkyl vinyl ether co-polymer). A release layer (surface layer) 51c made of polymer resin), polyimide, polyetherimide, PES (polyether sulfide), or the like is formed. When the metal substrate 51a is used, an infrared absorption layer 51d such as black paint or black nickel plating is provided on the back surface of the metal substrate 51a. Further, as shown in FIG. 4, the fixing member 51 ′ includes an elastic layer 51f made of silicon rubber or the like of about 100 to 300 μm on a resin base 51e made of a heat-resistant resin such as polyimide, polyamide, or fluorine resin, PFA ( A release layer (surface layer) 51 g made of tetrafluoroethylene bar fluoroalkyl vinyl ether copolymer resin), polyimide, polyetherimide, PES (polyether sulfide), or the like may be formed. The black and white fixing members 51 and 51 ′ may have a configuration in which an elastic layer such as silicon rubber is omitted from the above configuration. The fixing members 51 and 51 ′ configured as described above have a low heat capacity compared to a conventional fixing roller having a large heat capacity. The pressure plate 55 disposed in the loop of the fixing members 51 and 51 ′ is a metal plate (or a plate made of ceramic or polyimide resin) having a thickness of about 0.1 mm, and has a substantially cross-sectional shape. A U-shape is formed, and a desired nip portion is formed by contacting the pressure roller 52 via the fixing member 51.

上記加圧ローラ５２は、芯金上に弾性層を形成したものである。加圧ローラ５２の弾性層は、フッ素ゴム、シリコンゴム、発泡性シリコンゴム等の材料で形成されている。なお、弾性層の表層にＰＦＡ等からなる薄肉の離型層（チューブ）を設けることもできる。図２に示す加圧ローラ６の構成では、定着装置５のフレーム５０の側板（固定位置）に軸受を介して回転自在に設置されている。そして、加圧ローラ５２は不図示の駆動手段である駆動モータによって所定方向に回転駆動されて、定着部材５１は加圧ローラ５２との摩擦力によって所定方向に従動回転することになる。後述するように、定着部材５１は、定着動作時には図中矢印で示す時計回り方向（以下、通紙方向という）に回転し、温度立ち上げ動作時には、図中矢印で示す方向とは逆方向の反時計回り方向（以下、逆方向という）に回転する。   The pressure roller 52 is formed by forming an elastic layer on a cored bar. The elastic layer of the pressure roller 52 is made of a material such as fluorine rubber, silicon rubber, or foamable silicon rubber. A thin release layer (tube) made of PFA or the like may be provided on the surface layer of the elastic layer. In the configuration of the pressure roller 6 shown in FIG. 2, the pressure roller 6 is rotatably installed on a side plate (fixed position) of the frame 50 of the fixing device 5 via a bearing. The pressure roller 52 is rotationally driven in a predetermined direction by a drive motor which is a driving means (not shown), and the fixing member 51 is driven to rotate in a predetermined direction by a frictional force with the pressure roller 52. As will be described later, the fixing member 51 rotates in a clockwise direction indicated by an arrow in the drawing (hereinafter referred to as a paper passing direction) during a fixing operation, and in a direction opposite to the direction indicated by the arrow during a temperature raising operation. It rotates in the counterclockwise direction (hereinafter referred to as the reverse direction).

また、熱供給手段たるヒータ５３と反射板５４は、上記定着部材５１のループ内の図中右側に配置されている。ヒータ５３には、カーボンヒータやハロゲンヒータ等の赤外線ヒータが用いられ、その長手方向両端部が保持部材を介して定着装置５のフレーム５０の側板に固定されている。ヒータ５３には、後述するように、装置本体の電源部から制御部によって出力制御された電力が供給される。ここでは、反射板５４が、図中、定着部材５１の所定の領域にヒータ５３からの熱線を反射照射するように配置されている。以下、定着装置５において、ヒータ５３及び反射板５４により熱線が供給される所定の領域を熱供給領域という。ヒータ５３及び反射板５４によって熱供給領域で加熱された定着部材５１の加熱箇所がニップ部で用紙Ｐ上のトナー像に熱を加える。ここで、定着部材５１の熱供給領域は、熱供給領域の通紙方向上流側端部からニップ部までの距離が、通紙方向下流側端部からニップ部までの距離よりも長くなるように定められている。特に、図２に示すように、定着部材５１の熱供給領域は、後述するように、ニップ部から通紙方向上流側に定着部材５１の全長の２分の１長さまで進んだ領域内、つまり定着部材５１の図中右半分の領域であることが好ましい。   Further, the heater 53 and the reflection plate 54 as heat supply means are arranged on the right side in the drawing in the loop of the fixing member 51. As the heater 53, an infrared heater such as a carbon heater or a halogen heater is used, and both longitudinal ends thereof are fixed to the side plate of the frame 50 of the fixing device 5 via a holding member. As will be described later, the heater 53 is supplied with power whose output is controlled by the control unit from the power supply unit of the apparatus main body. Here, the reflection plate 54 is arranged so as to reflect and radiate heat rays from the heater 53 to a predetermined region of the fixing member 51 in the drawing. Hereinafter, in the fixing device 5, a predetermined area where heat rays are supplied by the heater 53 and the reflection plate 54 is referred to as a heat supply area. The heated portion of the fixing member 51 heated in the heat supply area by the heater 53 and the reflecting plate 54 applies heat to the toner image on the paper P at the nip portion. Here, the heat supply area of the fixing member 51 is such that the distance from the upstream end of the heat supply area in the sheet passing direction to the nip is longer than the distance from the downstream end in the sheet passing direction to the nip. It has been established. In particular, as shown in FIG. 2, the heat supply area of the fixing member 51 is within an area that extends from the nip portion to the upstream side in the sheet passing direction to half the total length of the fixing member 51, as will be described later. The right half region of the fixing member 51 in the drawing is preferable.

また、上記定着装置５は、定着部材５１の内周面（以下、裏面という）の温度を検出する温度検出手段である裏面温度検知センサ５６や、定着部材５１の外周面（以下、表面という）の温度を検知する表面温度検知手段である表面温度検知センサ５７を備えている。上記裏面温度センサ５６は、定着部材５１の裏面の熱供給領域よりも通紙方向上流側に隣接する領域の温度を検出するように配置される。上記表面温度センサ５７は、定着部材表面の熱供給領域中通紙方向下流側端部領域の温度を検出するように配置される。各温度センサ５６、５７は、サーモパイルや接触式のサーミスタ等の温度検知センサである。ここで、定着部材５１の裏面の温度検出を行なっているのは、次のような理由のためである。定着部材５１の構成が、熱容量が小さい金属等の基体に熱抵抗が大きい弾性層を付けた構成である場合には、裏面から供給される熱は熱抵抗が大きい弾性層で熱伝導が制限され、金属等の基体に蓄積して基体の温度が急激に上昇する。弾性層は、耐熱温度があるため、金属等の基体との界面でこの耐熱温度を超えてしまうと変形したり変質したりして故障の原因となってしまう。そのため、急激に温度を上昇させる定着装置５においては、定着部材５１の裏面の温度を管理する必要があり、裏面温度検知センサ５６の設置が必要となる。   The fixing device 5 includes a back surface temperature detection sensor 56 that is a temperature detecting means for detecting the temperature of the inner peripheral surface (hereinafter referred to as the back surface) of the fixing member 51 and the outer peripheral surface (hereinafter referred to as the front surface) of the fixing member 51. There is provided a surface temperature detection sensor 57 which is a surface temperature detection means for detecting the temperature. The back surface temperature sensor 56 is disposed so as to detect the temperature of the region adjacent to the upstream side in the sheet passing direction from the heat supply region on the back surface of the fixing member 51. The surface temperature sensor 57 is arranged so as to detect the temperature of the end region on the downstream side in the sheet passing direction in the heat supply region on the surface of the fixing member. Each of the temperature sensors 56 and 57 is a temperature detection sensor such as a thermopile or a contact type thermistor. Here, the temperature of the back surface of the fixing member 51 is detected for the following reason. When the fixing member 51 has a structure in which an elastic layer having a large thermal resistance is attached to a base such as a metal having a small heat capacity, the heat supplied from the back surface is limited by the elastic layer having a large thermal resistance. The temperature of the substrate rises rapidly due to accumulation on the substrate of metal or the like. Since the elastic layer has a heat-resistant temperature, if the heat-resistant temperature is exceeded at the interface with a substrate such as a metal, the elastic layer may be deformed or deteriorated to cause a failure. Therefore, in the fixing device 5 that rapidly increases the temperature, it is necessary to manage the temperature of the back surface of the fixing member 51, and it is necessary to install the back surface temperature detection sensor 56.

このように構成された定着装置５は次のように動作する。図６（ａ）は図５に示す定着装置の動作タイミングを示すタイミングチャート、（ｂ）は定着部材と加圧ローラの温度変化を示す特性図である。まず、図６（ａ）に示すように、印刷命令等のジョブトリガー信号により、定着部材５１を回転駆動させる定着駆動モータにより定着部材５１を定着動作時の通紙方向とは反対方向となる逆方向及び定着動作時の回転速度より遅い速度で回転駆動させる。同時にヒータ５３をディーティー１００％（電力ｍａｘ）にて点灯開始し、熱供給領域における定着部材５１を加熱する。定着部材５１の熱供給領域は約半回転するまでは加圧ローラ５２と接することがないため、図６（ｂ）で示すように、定着部材５１の表面温度は急激に昇温する。加圧ローラ５２はこの間加熱されないため初期温度のままである。最短での温度立ち上がりとするためには、定着部材５１の逆回転量は１回転（図６（ｂ）に図示）であってもよいが、立ち上がりが少し遅くもよい場合には、複数回転させてもよい。定着部材５１を複数回逆回転させる場合には、図６（ａ）に示すように、裏面温度センサ５６によって、定着部材５１の裏面の温度のモニターを開始する。その後、この裏面温度センサ５６の出力がある所定の設定温度を検知した時（定着部材裏面温度判断がＯＮ）に、定着部材５１の駆動開始時刻から設定温度を検知した時刻までの時間を測定し、定着部材５１の回転数が次の整数値の回転数になるまで上記動作を継続する。   The fixing device 5 configured as described above operates as follows. 6A is a timing chart showing the operation timing of the fixing device shown in FIG. 5, and FIG. 6B is a characteristic diagram showing temperature changes of the fixing member and the pressure roller. First, as shown in FIG. 6A, a fixing drive motor that rotates the fixing member 51 in response to a job trigger signal such as a print command causes the fixing member 51 to be in a direction opposite to the paper passing direction during the fixing operation. It is rotated at a speed slower than the direction and the rotational speed during the fixing operation. At the same time, the heater 53 is turned on at duty 100% (power max) to heat the fixing member 51 in the heat supply area. Since the heat supply area of the fixing member 51 does not come into contact with the pressure roller 52 until about half of the rotation, the surface temperature of the fixing member 51 rapidly increases as shown in FIG. 6B. Since the pressure roller 52 is not heated during this time, it remains at the initial temperature. In order to obtain the shortest temperature rise, the reverse rotation amount of the fixing member 51 may be one rotation (shown in FIG. 6B). May be. When the fixing member 51 is reversely rotated a plurality of times, monitoring of the temperature of the back surface of the fixing member 51 is started by the back surface temperature sensor 56 as shown in FIG. Thereafter, when the output of the back surface temperature sensor 56 detects a predetermined set temperature (fixing member back surface temperature determination is ON), the time from the driving start time of the fixing member 51 to the time when the set temperature is detected is measured. The above operation is continued until the rotation speed of the fixing member 51 reaches the next integer rotation speed.

ここで、定着部材５１の温度立ち上げ動作時、定着部材５１を１回転から整数回逆回転させる理由は、定着部材５１の熱供給領域を限定している為である。つまり、局所的に加熱している箇所から中途半端なところで回転方向を変えると、定着部材５１の温度が場所により異なってしまうからである。定着部材５１を全周に亘って均等な温度にする為には、定着部材５１の全周に亘って均一に熱を供給する必要があり、定着部材５１を整数回単位で回転させなければいけない。   Here, during the temperature raising operation of the fixing member 51, the reason why the fixing member 51 is reversely rotated from one rotation to an integer number is that the heat supply area of the fixing member 51 is limited. That is, if the rotation direction is changed at a halfway point from the locally heated location, the temperature of the fixing member 51 varies depending on the location. In order to make the fixing member 51 have a uniform temperature over the entire circumference, it is necessary to supply heat uniformly over the entire circumference of the fixing member 51, and the fixing member 51 must be rotated in integer units. .

そして、定着部材５１が次の整数値の回転数まで回転駆動したところで、定着駆動モータを停止し、定着部材５１の駆動に僅かな停止時間を設ける。この定着部材５１の僅かな停止時時間には、ヒータへの電力供給を一旦停止することで、定着部材５１への熱供給量を均一にする。その後、定着駆動モータによって定着動作（印刷）時の回転方向となる通紙方向及び印刷設定速度に定着部材５１を回転制御すると同時に、表面温度検知センサ５７により定着部材５１表面の温度を測定し、制御部はその検知温度に基づきヒータへの電力を制御する。このとき、定着部材５１の昇温速度は、定着部材５１に与えた熱がニップ部を通して加圧ローラ５２へ流れるために鈍化する。一方、加圧ローラ５２は定着部材５１により熱を供給されて温度が上昇する。   When the fixing member 51 is rotationally driven to the next integer number of rotations, the fixing drive motor is stopped, and a slight stop time is provided for driving the fixing member 51. During the slight stop time of the fixing member 51, the power supply to the heater is temporarily stopped to make the heat supply amount to the fixing member 51 uniform. Thereafter, the fixing member 51 is rotationally controlled by the fixing drive motor to the sheet passing direction which is the rotation direction during the fixing operation (printing) and the print setting speed, and at the same time, the surface temperature detection sensor 57 measures the surface temperature of the fixing member 51, The control unit controls the power to the heater based on the detected temperature. At this time, the temperature increase rate of the fixing member 51 is slowed down because heat applied to the fixing member 51 flows to the pressure roller 52 through the nip portion. On the other hand, the pressure roller 52 is supplied with heat by the fixing member 51 and the temperature rises.

その後、表面温度センサ５７によって検知した検知温度が所定の定着可能温度を検知したタイミングで、印刷（プリント）開始信号を出し印刷を開始する。印刷開始信号によって、上述したように、用紙Ｐが給紙カセット４から給送さて、プロセスユニット１にて用紙Ｐ上に未定着画像が担持される。未定着画像Ｔ（トナー像）が担持された用紙Ｐは、入口ガイド板５８に案内されながら搬送されて、圧接状態にある定着部材５１及び加圧ローラ５２のニップ部に送入される。そして、ヒータ５３によって加熱された定着部材５１による加熱と、定着部材５１と加圧ローラ６との押圧力とによって、用紙Ｐの表面にトナー像Ｔが定着される。用紙Ｐが通過した定着部材５１の表面温度は図中点線で示すように低下するが、ヒータ５３によるニップ部手前の加熱により定着部材５１は定着温度にもち上げられるため、温度検知出力としては変化がみられない。一方、加圧ローラ５２は、一枚目の用紙による奪われる熱量と定着部材５１から供給される熱量との関係により、通紙以前の昇温カーブが変化することになる。   Thereafter, at the timing when the detected temperature detected by the surface temperature sensor 57 detects a predetermined fixable temperature, a printing start signal is issued and printing is started. As described above, the paper P is fed from the paper feed cassette 4 by the print start signal, and an unfixed image is carried on the paper P in the process unit 1. The paper P on which the unfixed image T (toner image) is carried is conveyed while being guided by the entrance guide plate 58, and is fed into the nip portion between the fixing member 51 and the pressure roller 52 that are in a pressure contact state. The toner image T is fixed on the surface of the paper P by the heating by the fixing member 51 heated by the heater 53 and the pressing force of the fixing member 51 and the pressure roller 6. Although the surface temperature of the fixing member 51 through which the paper P has passed decreases as shown by the dotted line in the figure, the fixing member 51 is raised to the fixing temperature by the heating before the nip portion by the heater 53, so that the temperature detection output changes. Is not seen. On the other hand, the temperature increase curve before passing through the pressure roller 52 changes depending on the relationship between the amount of heat taken away by the first sheet and the amount of heat supplied from the fixing member 51.

なお、上記実施形態では、定着部材５１として定着ベルトを用いた構成であったが、他の構成であってもよい。図５は、別の実施形態に係る定着装置の構成を示す概略構成図である。なお、図５中、図２で示す部材と同一部材には同一符号を付し、説明を省略する。図５に示す定着装置６は、定着部材として薄肉のアルミやステンレスからなる金属ローラを用いた定着ローラを採用している。定着ローラから構成される定着部材６１は、定着ベルトから構成される定着部材５１と同様に、従来の熱容量の大きい定着ローラに比べ低熱容量化が図られている。定着ローラからなる定着部材６１の構成としては、図３に示すように、上記定着ベルトからなる定着部材５１と同様の構成を用いるとよい。図５に示す定着部材６１は、定着装置６のフレームの側板に軸受けを介して回転自在に設置されており、不図示の駆動手段である駆動モータによって回転駆動される。定着ローラから構成される定着部材６１を用いる場合には上記加圧板５５を設けない。   In the above-described embodiment, the fixing belt is used as the fixing member 51. However, other configurations may be used. FIG. 5 is a schematic configuration diagram illustrating a configuration of a fixing device according to another embodiment. In FIG. 5, the same members as those shown in FIG. The fixing device 6 shown in FIG. 5 employs a fixing roller using a metal roller made of thin aluminum or stainless steel as a fixing member. The fixing member 61 composed of the fixing roller has a lower heat capacity than the conventional fixing roller having a large heat capacity, like the fixing member 51 composed of the fixing belt. As the configuration of the fixing member 61 made of the fixing roller, as shown in FIG. 3, the same configuration as the fixing member 51 made of the fixing belt may be used. The fixing member 61 shown in FIG. 5 is rotatably installed on the side plate of the frame of the fixing device 6 via a bearing, and is rotationally driven by a driving motor which is a driving means (not shown). When the fixing member 61 composed of a fixing roller is used, the pressure plate 55 is not provided.

また、上記実施形態では、ヒータ５３から離間した位置に反射板５４を設置したが、ヒータ５３を覆うガラス管の一部に金メッキやアルミニウム蒸着を施してもよい。この場合にも、ガラスに施した金メッキやアルミニウム蒸着が反射部材として機能して熱供給領域における定着部材５１へ効率よく熱を供給することができる。   Moreover, in the said embodiment, although the reflecting plate 54 was installed in the position away from the heater 53, you may give gold plating and aluminum vapor deposition to a part of glass tube which covers the heater 53. FIG. Also in this case, gold plating or aluminum deposition applied to the glass functions as a reflecting member, and heat can be efficiently supplied to the fixing member 51 in the heat supply region.

次に、図７で示す本実施形態に係るオンデマンド定着方式の定着装置６と、図８で示す従来のオンデマンド定着方式の定着装置１００とにおいて、温度立ち上がり特性（定着部材と加圧ローラの温度変化）を比較した結果を図９に基づいて説明する。なお、図８に示す定着装置１００において、定着部材１０１、加圧ローラ１０２、ヒータ１０３は、図７に示す定着部材６１、加圧ローラ５２、ヒータ５３と同一規格のものである。また、図９中の定着部材と加圧ローラの温度は、図７及び図８に示す温度測定位置Ａ、Ｂ、Ｃ、Ｄで測定したものである。図８に示すように、従来の定着装置１００は、温度立ち上げ動作時も、印刷時と同様の回転方向及び回転速度で定着部材１０１を回転駆動し、定着部材１０１内部に配置したヒータ１０３からの熱を定着部材１０１全面に均一に供給している。そのため、定着部材１０１に供給された熱は、温度立ち上げ時（電力供給開始時）からニップ部を介して加圧ローラ１０２側の図８中１点斜線で示す領域に移動する。そのため、図９の点線で示すように定着部材１０１表面の昇温傾きが小さくなり定着可能となる時間が長くなっている。これに対し、本実施形態に係る定着装置６においては、図７に示すように、定着部材６１の熱供給領域を限定し、温度立上動作初期に定着部材６１を印刷時の通紙方向とは逆方向に回転させている。そのため、定着部材６１が約1半回転する間は、定着部材６１に供給した熱がニップ部を通して加圧ローラ５２側に熱が移動しない。よって、図９の実線で示すように、定着部材６１は、従来の定着部材１０１に比べ昇温速度が速く、定着部材６１が約１回転弱する間は加圧ローラ５２の温度が変化しない。また、逆回転時の速度を遅くすればするほど定着部材６１のみに熱量を与える時間を長くすることができ、定着可能な温度に到達する時間が短くすることができる。従来の定着装置１００も、立ち上げ時間が数秒と短いオンデマンド定着装置を採用したものであるが、本実施形態に係る定着装置５は、さらにその立ち上げ時間を短縮することができるものである。また、このような形態をとることにより、加圧ローラ５２を離間せずとも効果的に定着部材６１のみを温度上昇させることができる。さらに、従来の定着装置１００は、図８中矢印で示すように、印刷動作時の定着部材１０１から外気へ散逸する熱量が多いため、熱効率が低下している。これに対し、本実施形態に係る定着装置６においては、図７中矢印で示すように、ニップ部よりも通紙方向上流位置の熱供給領域からのみ熱が放出されるため、ヒータ５３から供給される熱量のうち大気へ放出される熱量の割合も減る。つまり、定着部材６１に供給した熱を効果的に未定着画像へ与えることができることによって、熱効率が上がり消費電力を抑えることができる。   Next, in the on-demand fixing type fixing device 6 according to this embodiment shown in FIG. 7 and the conventional on-demand fixing type fixing device 100 shown in FIG. The result of comparing the (temperature change) will be described with reference to FIG. In the fixing device 100 shown in FIG. 8, the fixing member 101, the pressure roller 102, and the heater 103 are of the same standard as the fixing member 61, the pressure roller 52, and the heater 53 shown in FIG. Further, the temperatures of the fixing member and the pressure roller in FIG. 9 are measured at the temperature measurement positions A, B, C, and D shown in FIGS. As shown in FIG. 8, the conventional fixing device 100 rotates the fixing member 101 at the same rotational direction and rotational speed as during printing, even during the temperature raising operation, and the heater 103 disposed inside the fixing member 101. The heat is uniformly supplied to the entire surface of the fixing member 101. Therefore, the heat supplied to the fixing member 101 moves from the time of temperature rise (at the start of power supply) to the area indicated by the one-dotted diagonal line in FIG. Therefore, as shown by the dotted line in FIG. 9, the temperature rising gradient on the surface of the fixing member 101 is reduced, and the time for fixing can be increased. On the other hand, in the fixing device 6 according to the present embodiment, as shown in FIG. 7, the heat supply area of the fixing member 61 is limited, and the fixing member 61 is set to the paper passing direction during printing at the initial stage of the temperature rising operation. Is rotating in the opposite direction. Therefore, the heat supplied to the fixing member 61 does not move to the pressure roller 52 side through the nip portion while the fixing member 61 rotates about one half. Therefore, as indicated by the solid line in FIG. 9, the fixing member 61 has a higher temperature rising speed than the conventional fixing member 101, and the temperature of the pressure roller 52 does not change while the fixing member 61 is less than about one rotation. In addition, the slower the reverse rotation speed, the longer the time for applying heat to the fixing member 61 alone, and the shorter the time for reaching the fixable temperature. The conventional fixing device 100 also employs an on-demand fixing device with a short startup time of several seconds, but the fixing device 5 according to the present embodiment can further reduce the startup time. . Further, by adopting such a form, it is possible to effectively raise the temperature of only the fixing member 61 without separating the pressure roller 52. Furthermore, the conventional fixing device 100 has a low heat efficiency because the amount of heat dissipated from the fixing member 101 to the outside air during the printing operation is large as indicated by the arrows in FIG. On the other hand, in the fixing device 6 according to this embodiment, as indicated by an arrow in FIG. 7, heat is released only from the heat supply area upstream of the nip portion in the sheet passing direction. The proportion of the amount of heat released to the atmosphere is also reduced. That is, the heat supplied to the fixing member 61 can be effectively applied to the unfixed image, so that the thermal efficiency is increased and the power consumption can be suppressed.

以上、本実施形態に係る定着装置５、６によれば、熱供給手段であるヒータ５３（反射板５４）によって加熱される熱供給領域の定着動作時の回転方向上流側端部（温度立ち上げ動作時の回転方向下流側）端部がニップ部から所定距離離れている。そのため、定着部材５１、６１の温度立ち上げ動作時には、定着部材５１、６１の回動に伴って熱供給領域で加熱された定着部材５１、６１の加熱箇所がニップ部に到達するまで、ニップ部を介した加圧部材である加圧ローラ５２への熱伝達を抑制でき、その分定着部材５１、６１の温度立ち上げ時間を短縮することができる。そして、定着部材５１、６１は温度立ち上げ動作時と定着動作時とで回転方向が逆方向である。これにより、立ち上げ動作時には定着部材５１、６１の加熱箇所がニップ部に到達するまでの距離をとることができ、定着動作時には定着部材５１、６１の加熱箇所がニップ部に直ちに到達するような構成をとることができる。また、定着動作時においても、定着部材５１、６１の定められた熱供給領域に熱が供給されるため、定着部材５１、６１の全域を加熱する場合に比べ空気中に散逸する熱量が少なく熱効率がよい。
また、本実施形態に係る定着装置５、６によれば、定着部材５１、６１の熱供給領域は、熱供給領域の通紙方向上流側端部からニップ部までの距離が、熱供給領域の通紙方向下流側端部からニップ部までの距離より長くなるように定められている。そのため、定着部材５１、６１の温度立ち上げ時には、定着部材５１、６１を逆回転させることにより、通紙方向に回転させる場合に比べ加熱箇所がニップ部に到達するまでの距離を長くすることができる。その間、ニップ部を介した加圧ローラ５２への熱伝達を抑制できる。一方、定着部材５１、６１の定着動作時には、加熱箇所が直ちにニップ部に到達することができ熱効率がよい。
また、本実施形態に係る定着装置５、６によれば、定着部材５１、６１の温度立ち上げ動作時には、定着部材５１、６１の内周面温度を内周面温度検出手段である裏面温度センサ５６により検出することにより、温度立ち上げ動作から定着動作へ移行することができる。また、定着部材５１、６１の内周面温度を内周面温度センサ５６により検出することにより、定着部材５１、６１の温度を急激に上げるオンデマンド方式の定着装置５、６においても、局所的に耐熱温度を超えることを未然に防止でき、定着装置５、６の耐久性低下や故障を防止できる。
また、本実施形態に係る定着装置５、６によれば、定着部材５１、６１の温度立ち上げ動作時として、定着部材５１、６１を整数周分逆方向に回転駆動（従動回転も含む）させ、定着部材５１、６１の周方向に亘って均一に熱を供給している。これにより、定着部材５１、６１の温度が一定となり、記録媒体である用紙Ｐ上に定着されるトナー像の定着異常や光沢ムラ等を防止できる。
また、本実施形態に係る定着装置５、６によれば、定着部材５１、６１の温度立ち上げ動作時には、定着部材５１、６１を定着動作時の回転速度より遅い回転速度で回転駆動（従動回転も含む）させている。これにより温度立ち上げ時において、熱供給領域がニップ部に到達するまでの時間が長くなり、定着部材５１、６１の昇温速度を速めることができる。
また、本実施形態に係る定着装置５、６によれば、裏面温度センサ５６が熱供給領域の通紙方向上流側端部近傍に配置される。これにより、温度立ち上げ時における加熱直後の定着部材５１、６１の温度を測定でき、定着部材５１、６１が耐熱温度を超えることを未然に防止でき、信頼性が向上する。
また、本実施形態に係る定着装置５、６によれば、外周面温度検出手段である表面温度センサ５７が定着部材５１、６１の熱供給領域の通紙方向下流側端部近傍に配置される。これにより、定着動作時における加熱直後の定着部材５１、６１の温度を測定でき、定着部材５１、６１が耐熱温度を超えることを未然に防止でき、信頼性が向上する。また、定着動作時において、この表面温度センサ５７からの検出値を基にヒータ５３への電力供給制御を行うことができ、定着部材５１、６１の温度安定化を図ることができるため、高画質な画像を形成できる。
また、本実施形態に係る定着装置５、６によれば、定着部材５１、６１の温度立ち上げ時には、熱源であるヒータ５３に最大電力が供給されるため、定着部材５１、６１の温度を速やかに上げることができ、速やかな温度立ち上げが可能となる。また、定着動作時において、表面温度センサ５７からの検出値を基にヒータ５３への電力供給制御を行うことで、定着部材５１、６１の過熱防止、及び定着部材５１、６１の温度安定化を図ることができる。
また、本実施形態に係る定着装置５、６によれば、定着部材５１、６１の停止時間中にはヒータ５３に電力を供給しないため、定着部材５１、６１への熱供給量を周方向に亘って均一にでき、均一な定着性能を得ることができる。
また、本実施形態に係る定着装置５、６によれば、赤外線輻射による輻射加熱方法により定着部材５１、６１を高速で昇温することができる共に、定着動作時においても熱効率に優れる。
また、本実施形態に係るプリンタによれば、上述したように立ち上げ時間が短く、且つ定着時の熱効率にも優れた定着装置５、６を用いているため、省エネへの対応が可能となる。
なお、本実施形態では、オンデマンド方式の定着装置について言及したが、これに限定されるものではない。本発明は、例えば、定着ローラの内部に熱源を設けず、定着ローラの外部に配置された熱容量の小さい加熱ローラを熱源とし、この加熱ローラにより熱容量の小さい定着ベルトを加熱させ、その熱をニップ部まで運ぶ構成であるベルト定着方式にも適用可能である。
As described above, according to the fixing devices 5 and 6 according to the present embodiment, the upstream end portion (temperature rise) in the rotation direction during the fixing operation of the heat supply region heated by the heater 53 (reflecting plate 54) serving as the heat supply unit. The downstream end in the rotational direction during operation is separated from the nip by a predetermined distance. Therefore, during the temperature raising operation of the fixing members 51 and 61, the nip portion is kept until the heated portion of the fixing members 51 and 61 heated in the heat supply area as the fixing members 51 and 61 are rotated reaches the nip portion. Therefore, heat transfer to the pressure roller 52, which is a pressure member, can be suppressed, and the temperature rise time of the fixing members 51 and 61 can be shortened accordingly. The fixing members 51 and 61 rotate in opposite directions during the temperature raising operation and during the fixing operation. Accordingly, it is possible to take a distance until the heated portion of the fixing members 51 and 61 reaches the nip portion during the start-up operation, and the heated portion of the fixing members 51 and 61 immediately reaches the nip portion during the fixing operation. Configuration can be taken. Further, even during the fixing operation, heat is supplied to the predetermined heat supply area of the fixing members 51 and 61. Therefore, the amount of heat dissipated in the air is less than that in the case where the entire areas of the fixing members 51 and 61 are heated. Is good.
Further, according to the fixing devices 5 and 6 according to the present embodiment, the heat supply area of the fixing members 51 and 61 has a distance from the upstream end portion in the sheet feeding direction of the heat supply area to the nip portion of the heat supply area. It is determined to be longer than the distance from the downstream end portion in the sheet passing direction to the nip portion. For this reason, when the temperature of the fixing members 51 and 61 is increased, the distance until the heated portion reaches the nip portion can be increased by rotating the fixing members 51 and 61 in the reverse direction as compared with the case of rotating in the sheet passing direction. it can. Meanwhile, heat transfer to the pressure roller 52 via the nip portion can be suppressed. On the other hand, during the fixing operation of the fixing members 51 and 61, the heated portion can immediately reach the nip portion, and the thermal efficiency is good.
Further, according to the fixing devices 5 and 6 according to the present embodiment, when the temperature of the fixing members 51 and 61 is raised, the inner surface temperature of the fixing members 51 and 61 is a back surface temperature sensor that is an inner surface temperature detecting unit. By detecting by 56, the temperature rising operation can be shifted to the fixing operation. The on-demand type fixing devices 5 and 6 that rapidly increase the temperature of the fixing members 51 and 61 by detecting the inner peripheral surface temperature of the fixing members 51 and 61 by the inner peripheral surface temperature sensor 56 are also locally applied. In addition, it is possible to prevent the heat resistance temperature from being exceeded, and it is possible to prevent the durability of the fixing devices 5 and 6 from being deteriorated or broken.
Further, according to the fixing devices 5 and 6 according to the present embodiment, when the temperature of the fixing members 51 and 61 is raised, the fixing members 51 and 61 are rotationally driven (including driven rotation) in the opposite direction by an integer number of rounds. The heat is uniformly supplied over the circumferential direction of the fixing members 51 and 61. As a result, the temperature of the fixing members 51 and 61 becomes constant, and fixing abnormality of the toner image fixed on the paper P as a recording medium, gloss unevenness, and the like can be prevented.
Further, according to the fixing devices 5 and 6 according to the present embodiment, during the temperature raising operation of the fixing members 51 and 61, the fixing members 51 and 61 are rotationally driven at a rotational speed slower than the rotational speed during the fixing operation (followed rotation). Also included). As a result, when the temperature is raised, the time until the heat supply area reaches the nip portion becomes longer, and the temperature increase rate of the fixing members 51 and 61 can be increased.
Further, according to the fixing devices 5 and 6 according to the present embodiment, the back surface temperature sensor 56 is disposed in the vicinity of the upstream end of the heat supply area in the sheet passing direction. As a result, the temperature of the fixing members 51 and 61 immediately after heating when the temperature is raised can be measured, so that the fixing members 51 and 61 can be prevented from exceeding the heat resistance temperature, and the reliability is improved.
Further, according to the fixing devices 5 and 6 according to the present embodiment, the surface temperature sensor 57 that is the outer peripheral surface temperature detecting means is disposed in the vicinity of the downstream end of the heat supply area of the fixing members 51 and 61 in the sheet passing direction. . As a result, the temperature of the fixing members 51 and 61 immediately after heating during the fixing operation can be measured, and it is possible to prevent the fixing members 51 and 61 from exceeding the heat-resistant temperature, thereby improving the reliability. Further, during the fixing operation, power supply control to the heater 53 can be performed based on the detection value from the surface temperature sensor 57, and the temperature of the fixing members 51 and 61 can be stabilized. An image can be formed.
Further, according to the fixing devices 5 and 6 according to the present embodiment, when the temperature of the fixing members 51 and 61 is raised, the maximum power is supplied to the heater 53 that is a heat source. The temperature can be raised quickly, and a rapid temperature rise becomes possible. Further, during the fixing operation, power supply control to the heater 53 is performed based on the detection value from the surface temperature sensor 57, thereby preventing overheating of the fixing members 51 and 61 and stabilizing the temperature of the fixing members 51 and 61. Can be planned.
Further, according to the fixing devices 5 and 6 according to the present embodiment, since the power is not supplied to the heater 53 during the stop time of the fixing members 51 and 61, the heat supply amount to the fixing members 51 and 61 is set in the circumferential direction. And uniform fixing performance can be obtained.
Further, according to the fixing devices 5 and 6 according to the present embodiment, the fixing members 51 and 61 can be heated at a high speed by a radiant heating method using infrared radiation, and the thermal efficiency is also excellent during the fixing operation.
Further, according to the printer according to the present embodiment, as described above, since the fixing devices 5 and 6 having a short start-up time and excellent thermal efficiency at the time of fixing are used, it is possible to cope with energy saving. .
In the present embodiment, the on-demand fixing device has been described, but the present invention is not limited to this. In the present invention, for example, a heat source is not provided inside the fixing roller, but a heating roller having a small heat capacity disposed outside the fixing roller is used as a heat source. It can also be applied to a belt fixing system that is configured to carry to a part.

１ プロセスユニット
２ 転写ユニット
３ 光書込ユニット
４ 給紙カセット
５、６ 定着装置
５１、６１ 定着部材
５２ 加圧ローラ
５３ ヒータ
５４ 反射板
５５ 加圧板
５６ 裏面温度センサ
５７ 表面温度センサ DESCRIPTION OF SYMBOLS 1 Process unit 2 Transfer unit 3 Optical writing unit 4 Paper feed cassette 5, 6 Fixing device 51, 61 Fixing member 52 Pressure roller 53 Heater 54 Reflecting plate 55 Pressure plate 56 Back surface temperature sensor 57 Surface temperature sensor

特開２００４−６２０５３号公報JP 2004-62053 A 特開２００４−２５８４８４号公報JP 2004-258484 A 特開２００７−１６３６７７号公報JP 2007-163677 A

Claims (10)

回動可能な定着部材と、該定着部材に圧接してニップ部を形成する回転可能な加圧部材と、該定着部材に熱を供給する熱供給手段と、該加圧部材を回転させる駆動手段とを有し、該定着部材は該加圧部材によって従動回転され、該ニップ部に未定着画像を担持する記録媒体を通過させて定着を行う定着装置において、
上記熱供給手段により熱が供給される定着部材の熱供給領域は、上記ニップ部を除き、且つ定着動作時の回転方向上流側端部が該ニップ部から所定距離離れるように定められ、
上記駆動手段は、定着動作開始時の該定着部材の温度立ち上げ動作として、該定着部材を定着動作時の回転方向とは逆方向に整数周分回転させることを特徴とする定着装置。 A rotatable fixing member, a rotatable pressure member forming a nip portion in pressure contact with the fixing member, and the heat supply means for supplying heat to the fixing member, a drive for rotating the pressure member A fixing device in which the fixing member is driven and rotated by the pressure member, and a recording medium carrying an unfixed image is passed through the nip portion for fixing.
The heat supply area of the fixing member to which heat is supplied by the heat supply means is determined such that the upstream end in the rotational direction during the fixing operation is separated from the nip by a predetermined distance except for the nip.
The driving device rotates the fixing member by an integral number of revolutions in a direction opposite to the rotation direction during the fixing operation as a temperature raising operation of the fixing member at the start of the fixing operation. 請求項１の定着装置において、
上記定着部材の熱供給領域は、該熱供給領域の定着動作時の回転方向上流側端部から上記ニップ部までの距離が、該熱供給領域の定着動作時の回転方向下流側端部から該ニップ部までの距離よりも長くなるように定められていることを特徴とする定着装置。 The fixing device according to claim 1.
The heat supply area of the fixing member is such that the distance from the upstream end in the rotation direction during the fixing operation of the heat supply area to the nip portion is from the downstream end in the rotation direction during the fixing operation of the heat supply area. A fixing device characterized in that the fixing device is set to be longer than a distance to a nip portion. 請求項１又は２の定着装置において、
上記熱供給手段は、上記定着部材の内部に熱源を有し、
上記駆動手段は、該定着部材の内周面温度を検出する内周面温度検出手段により検出した温度にも基づき、該定着部材を逆方向に回転させる温度立ち上げ動作から、該定着部材を通紙方向に回転させる定着動作に移行することを特徴とする定着装置。 The fixing device according to claim 1 or 2,
The heat supply means has a heat source inside the fixing member,
Said drive means, from among even based on the temperature detected by the peripheral surface temperature detecting means, temperature raising operation for rotating the fixing member in the opposite direction to detect the inner circumferential surface temperature of the fixing member, the fixing member A fixing device that shifts to a fixing operation of rotating in a paper passing direction. 請求項１、２又は３の定着装置において、
上記駆動手段は、上記定着部材の温度立ち上げ動作として、該定着部材を定着動作時の回転速度より遅い回転速度で回転させることを特徴とする定着装置。 The fixing device according to claim 1, 2 or 3.
The fixing device is characterized in that, as the temperature raising operation of the fixing member, the driving means rotates the fixing member at a rotation speed slower than the rotation speed at the time of the fixing operation. 請求項３の定着装置において、
上記内周面温度検出手段を上記定着部材の熱供給領域の通紙方向上流側端部近傍に配置することを特徴とする定着装置。 The fixing device according to claim 3.
The fixing device, wherein the inner peripheral surface temperature detecting means is disposed in the vicinity of the upstream end of the heat supply area of the fixing member in the sheet passing direction. 請求項１、２、３、４又は５の定着装置において、
上記定着部材の外周面温度を検出する外周面温度検出手段を、上記定着部材の熱供給領域の通紙方向下流側端部近傍に配置することを特徴とする定着装置。 The fixing device according to claim 1, 2, 3, 4 or 5.
A fixing device, wherein an outer peripheral surface temperature detecting means for detecting an outer peripheral surface temperature of the fixing member is disposed in the vicinity of a downstream end portion in a sheet passing direction of a heat supply region of the fixing member. 請求項６の定着装置において、
上記熱供給手段は、上記定着部材の温度立ち上げ動作時には熱源に最大電力を供給し、定着動作移行後には上記外周面温度検出手段の検出結果に基づいて熱源に電力供給を行うことを特徴とする定着装置。 The fixing device according to claim 6.
The heat supply means supplies maximum power to the heat source during the temperature raising operation of the fixing member, and supplies power to the heat source based on the detection result of the outer peripheral surface temperature detection means after shifting to the fixing operation. Fixing device to do. 請求項７の定着装置において、
上記駆動手段は、上記定着部材の温度立ち上げ動作から定着動作への移行時に該定着部材を停止させる停止時間を設け、
上記熱供給手段は、該停止時間中は電力供給を停止することを特徴とする定着装置。 The fixing device according to claim 7.
The driving means provides a stop time for stopping the fixing member when the temperature of the fixing member is shifted from the temperature raising operation to the fixing operation.
The fixing device according to claim 1, wherein the heat supply means stops power supply during the stop time. 請求項１、２、３、４、５、６、７又は８の定着装置において、
上記熱供給手段は、赤外線を照射する赤外線ヒータと、該赤外線ヒータからの赤外線を反射する反射板とを備え、
上記定着部材は赤外線を吸収して発熱する発熱層を備えていることを特徴とする定着装置。 The fixing device according to claim 1, 2, 3, 4, 5, 6, 7 or 8.
The heat supply means includes an infrared heater that irradiates infrared rays, and a reflector that reflects infrared rays from the infrared heater,
The fixing device, wherein the fixing member includes a heat generating layer that absorbs infrared rays and generates heat. 記録媒体に未定着画像を形成担持させる作像手段と、記録媒体上の未定着画像を定着させる定着手段とを備える画像形成装置において、
上記定着手段として、請求項１、２、３、４、５、６、７、８又は９の定着装置を用いることを特徴とする画像形成装置。 In an image forming apparatus comprising: an image forming unit that forms and supports an unfixed image on a recording medium; and a fixing unit that fixes an unfixed image on the recording medium.
An image forming apparatus using the fixing device according to claim 1, 2, 3, 4, 5, 6, 7, 8, or 9 as the fixing unit.
JP2013168163A 2013-08-13 2013-08-13 Fixing device and image forming apparatus using the same Expired - Fee Related JP5660475B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2013168163A JP5660475B2 (en) 2013-08-13 2013-08-13 Fixing device and image forming apparatus using the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2013168163A JP5660475B2 (en) 2013-08-13 2013-08-13 Fixing device and image forming apparatus using the same

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
JP2008286400A Division JP5344284B2 (en) 2008-11-07 2008-11-07 Fixing device and image forming apparatus using the same

Publications (2)

Publication Number Publication Date
JP2013228762A JP2013228762A (en) 2013-11-07
JP5660475B2 true JP5660475B2 (en) 2015-01-28

Family

ID=49676358

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2013168163A Expired - Fee Related JP5660475B2 (en) 2013-08-13 2013-08-13 Fixing device and image forming apparatus using the same

Country Status (1)

Country Link
JP (1) JP5660475B2 (en)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06332338A (en) * 1993-05-18 1994-12-02 Canon Inc Fixing device
JPH11327351A (en) * 1998-05-20 1999-11-26 Oki Data Corp Controller for fixing unit
JP2000029333A (en) * 1998-07-15 2000-01-28 Sharp Corp Fixing device
JP2000159407A (en) * 1998-11-20 2000-06-13 Canon Inc Fixing device and image forming device comprising the same
JP2002040871A (en) * 2000-07-28 2002-02-06 Ricoh Co Ltd Heater, fixing device, image forming device, and fixing method
JP2004020696A (en) * 2002-06-13 2004-01-22 Brother Ind Ltd Heat fixing device and image forming apparatus
JP2006133471A (en) * 2004-11-05 2006-05-25 Canon Inc Heating device and image forming apparatus
JP2008268561A (en) * 2007-04-20 2008-11-06 Canon Inc Image forming apparatus

Also Published As

Publication number Publication date
JP2013228762A (en) 2013-11-07

Similar Documents

Publication Publication Date Title
US9983526B2 (en) Fixing device and image forming apparatus including same
US9971289B2 (en) Image forming apparatus
JP5344284B2 (en) Fixing device and image forming apparatus using the same
JP6052598B2 (en) Fixing apparatus and image forming apparatus
US9383693B2 (en) Fixing device, image forming apparatus, and fixing method
US9389550B2 (en) Fixing device, image forming apparatus, and fixing method
US20150227095A1 (en) Fixing device and image forming apparatus
JP6299462B2 (en) Fixing apparatus and image forming apparatus
JP7277214B2 (en) image forming device
JP2011128291A (en) Fixing device and image forming apparatus
JP6874247B2 (en) Fixing device and image forming device
US9075358B2 (en) Image heating device
JP6319468B2 (en) Fixing apparatus and image forming apparatus
JP5660475B2 (en) Fixing device and image forming apparatus using the same
US11409214B2 (en) Fixing apparatus and image forming apparatus
JP2017120392A (en) Fixing device and image forming apparatus
JP6708000B2 (en) Fixing device and image forming apparatus
JP6617580B2 (en) Fixing apparatus and image forming apparatus
JP2022139860A (en) Fixing device and image forming apparatus
JP2017040949A (en) Fixing device and image forming apparatus
JP2017026903A (en) Fixation device and image formation device
JP2017090663A (en) Fixing device and image formation device
JP2016109895A (en) Fixing device and image forming apparatus
JP2014178589A (en) Fixing device, and image forming apparatus

Legal Events

Date Code Title Description
A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20130911

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20130911

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A132

Effective date: 20140725

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20140922

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20141107

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20141120

R151 Written notification of patent or utility model registration

Ref document number: 5660475

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R151

LAPS Cancellation because of no payment of annual fees