JPH086415A - Fixing device for image forming device - Google Patents
Fixing device for image forming deviceInfo
- Publication number
- JPH086415A JPH086415A JP6134574A JP13457494A JPH086415A JP H086415 A JPH086415 A JP H086415A JP 6134574 A JP6134574 A JP 6134574A JP 13457494 A JP13457494 A JP 13457494A JP H086415 A JPH086415 A JP H086415A
- Authority
- JP
- Japan
- Prior art keywords
- roller
- heating roller
- paper
- case
- fixing device
- 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.)
- Granted
Links
Landscapes
- Electrophotography Configuration And Component (AREA)
- Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
- Fixing For Electrophotography (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、レーザプリンタ、複写
機、ファクシミリ装置等の静電写真式等の画像形成装置
に関し、より詳しくは、用紙等の被記録媒体に転写され
たトナー像を定着する定着装置の構造に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a laser printer, a copying machine, a facsimile machine, and more particularly, to fixing a toner image transferred onto a recording medium such as paper. The present invention relates to the structure of the fixing device.
【0002】[0002]
【従来の技術】従来から、この種の定着方式として、オ
ーブンによる非接触加熱定着方式、フラッシュランプに
よる光定着方式、加圧ローラ対による圧力定着方式及び
加熱ローラと押圧ローラとの対による接触加熱方式等が
知られている。そして、従来の加熱ローラと押圧ローラ
との対による接触加熱方式では、定着装置の本体フレー
ムに加熱ローラ及び押圧ローラの左右両側端の軸受部を
設ける一方、画像形成ユニット側から給送された被記録
媒体を加熱ローラと押圧ローラとの間(定着部位)に案
内するための前ガイド部材および定着部位から出た被記
録媒体を排出ガイド部に案内するための後ガイド部材
を、前記本体フレームにに取付けた後、加熱ローラの上
方を覆うための上カバー体を本体フレームに取りつけ
る。また、定着装置における加熱ローラから受ける熱に
より用紙等の被記録媒体は当該加熱ローラの円周面に巻
きつくように湾曲するので、被記録媒体を加熱ローラの
周面から剥離するため、加熱ローラより被記録媒体の搬
送下流側には、当該加熱ローラの周面に極めて接近させ
て用紙剥離爪または剥離ガイド部材を本体フレームに取
りつけるというような構成であった。2. Description of the Related Art Conventionally, as this type of fixing method, a non-contact heat fixing method using an oven, a light fixing method using a flash lamp, a pressure fixing method using a pressure roller pair, and a contact heating method using a pair of a heating roller and a pressure roller are used. The method etc. are known. In the conventional contact heating method using a pair of a heating roller and a pressing roller, the main body frame of the fixing device is provided with bearings at both left and right ends of the heating roller and the pressing roller, while the sheet fed from the image forming unit is fed. A front guide member for guiding the recording medium between the heating roller and the pressing roller (fixing portion) and a rear guide member for guiding the recording medium discharged from the fixing portion to the discharge guide portion are provided on the main body frame. Then, the upper cover body for covering the upper side of the heating roller is attached to the main body frame. Further, since the recording medium such as a sheet of paper is curved so as to wind around the circumferential surface of the heating roller due to the heat received from the heating roller in the fixing device, the recording medium is separated from the circumferential surface of the heating roller. Further, on the downstream side of conveyance of the recording medium, the paper peeling claw or the peeling guide member is attached to the main body frame so as to be extremely close to the peripheral surface of the heating roller.
【0003】[0003]
【発明が解決しようとする課題】しかしながら、このよ
うな従来の構成であると、部品が多いため定着装置を組
み立てるのに手間が掛かり、且つ隣接する部品間の位置
調節作業も必要であるから、定着装置の製造コストが高
くなるという問題があった。また、前述のように用紙剥
離爪や剥離ガイド部材で被記録媒体の先端が加熱ローラ
から離れても、用紙剥離爪や剥離ガイド部材の縁が被記
録媒体の画像面に接触しつつ搬送された場合には、画像
面のトナーが用紙剥離爪や剥離ガイド部材の縁に付着す
る。さらにこの付着したトナーが積み重なって、ますま
す被記録媒体の画像面に対して擦れ易くなり、画像の質
が悪くなるという問題があった。However, with such a conventional structure, it is troublesome to assemble the fixing device due to the large number of parts, and the position adjustment work between adjacent parts is also necessary. There is a problem that the manufacturing cost of the fixing device becomes high. Further, as described above, even when the leading edge of the recording medium is separated from the heating roller by the paper peeling claw or the peeling guide member, the edge of the paper peeling claw or the peeling guide member is conveyed while being in contact with the image surface of the recording medium. In this case, the toner on the image surface adheres to the edge of the paper peeling claw or the peeling guide member. Further, there is a problem that the adhered toner accumulates and becomes more likely to rub against the image surface of the recording medium, resulting in poor image quality.
【0004】この問題を解決するには、前記用紙剥離爪
や剥離ガイド部材をトナーの付着し難い材質にて構成し
たり、そのような材料の塗装膜をコーテイングする等の
処理を施していたため、これによっても製造コストが上
昇するのであった。本発明は、これらの技術的課題を解
決すべくなされたものであって、定着装置の構造を簡単
化しつつ、且つ製造コストを低減することができる画像
形成装置の定着装置を提供することを目的とし、さら
に、良好な画質を得られるようにした画像形成装置を提
供することを目的とするものである。In order to solve this problem, the paper peeling claw and the peeling guide member are made of a material to which toner is hard to adhere, or a coating film of such a material is coated, and the like. This also increased the manufacturing cost. The present invention has been made to solve these technical problems, and an object of the present invention is to provide a fixing device for an image forming apparatus that can simplify the structure of the fixing device and reduce the manufacturing cost. Further, it is an object of the present invention to provide an image forming apparatus capable of obtaining good image quality.
【0005】[0005]
【課題を解決するための手段】前記目的を達成するた
め、請求項1記載の発明の画像形成装置の定着装置は、
ほぼ水平な回転軸線回りに回転する加熱ローラと押圧ロ
ーラとにより、トナー像が転写された用紙等の被記録媒
体に熱と圧力を付与してトナー像を定着させるように構
成し、該定着装置の本体ケースを、加熱ローラと押圧ロ
ーラとの外周を覆うようにした上下2つのケースに分割
し、加熱ローラの外周を覆う一方のケースには、加熱ロ
ーラの被記録媒体搬送下流側周面に縁部が近接するよう
に沿設した用紙剥離ガイド部材を一体的に形成したもの
である。In order to achieve the above object, a fixing device for an image forming apparatus according to claim 1 is
A heating roller and a pressing roller that rotate around a substantially horizontal rotation axis are configured to apply heat and pressure to a recording medium such as paper on which the toner image is transferred to fix the toner image. The main body case is divided into two upper and lower cases that cover the outer circumferences of the heating roller and the pressing roller, and one case that covers the outer circumference of the heating roller has a peripheral surface on the downstream side of the recording medium conveyance of the heating roller. The sheet peeling guide member is integrally formed along the edge portion so as to be close to each other.
【0006】また、請求項2記載の発明の画像形成装置
の定着装置は請求項1記載の構成の他に、前記一方のケ
ースには、前記加熱ローラの周面に近接した前記用紙剥
離ガイド部材の縁部から被記録媒体搬送下流側に向かっ
て縁が延びるリブを突設し、該リブの縁を、加熱ローラ
の周面と逆向きに湾曲するように形成したものである。Further, in addition to the constitution of the fixing device of the image forming apparatus of the invention described in claim 2, in the one case, the paper peeling guide member close to the peripheral surface of the heating roller is provided in the one case. A rib is provided so that the edge extends from the edge portion toward the downstream side of the recording medium conveyance, and the edge of the rib is formed so as to be curved in the direction opposite to the peripheral surface of the heating roller.
【0007】また、請求項3記載のの画像形成装置の定
着装置発明は、請求項1または請求項2記載の構成の他
に、前記一方のケースには、前記用紙剥離ガイド部材の
縁部から被記録媒体搬送下流側に適宜離れた位置に、被
記録媒体が当接する遊びコロを回転自在に設けたもので
ある。According to a third aspect of the invention, there is provided a fixing device invention for an image forming apparatus, wherein, in addition to the configuration according to the first or second aspect, the one case includes an edge portion of the sheet peeling guide member. A play roller with which the recording medium abuts is rotatably provided at a position appropriately separated on the downstream side of the recording medium conveyance.
【0008】[0008]
【実施例】次に、本発明を具体化した実施例について説
明する。図1は画像形成装置としてのレーザビーム式プ
リンタ1の概略側断面図、図2は定着装置の縦断面図で
ある。本実施例のプリンタ1における装置本体2内の下
部に給紙部としての給紙カセット3を着脱自在に装着
し、複数の給紙ローラ4等により、給紙カセット3内に
積層された被記録媒体としての用紙Pが一枚ずつに分離
されて用紙中途ガイド板5や給送ローラ対6を介して画
像形成ユニット7と転写ユニット台8上の転写ローラ9
との間に送られる。Next, an embodiment of the present invention will be described. FIG. 1 is a schematic side sectional view of a laser beam printer 1 as an image forming apparatus, and FIG. 2 is a vertical sectional view of a fixing device. In the printer 1 of this embodiment, a paper feed cassette 3 as a paper feed unit is removably attached to the lower portion of the apparatus main body 2, and a plurality of paper feed rollers 4 and the like stack recording in the paper feed cassette 3. The paper P as a medium is separated one by one, and the image forming unit 7 and the transfer roller 9 on the transfer unit base 8 are separated via the paper midway guide plate 5 and the feeding roller pair 6.
Sent between and.
【0009】画像形成ユニット7は、感光体ドラム10
と、トナータンクや現像ローラ12等からなる現像装置
ユニット11と、帯電ローラ等からなる帯電装置13、
クリーニング(図示しない)装置等を1つのキットとし
てケース内に収納して単一ユニットを構成している。画
像形成ユニット7の上方には、レーザ発光部23、レン
ズ24、反射鏡25等からなるスキャナユニット22が
配置されており、転写ユニット台8の下方には、前記帯
電装置13や転写ローラ9の高電圧を印加するための高
電圧基板26が配置され、定着装置15の下方に制御基
板27が配置されている。The image forming unit 7 includes a photosensitive drum 10.
A developing device unit 11 including a toner tank and a developing roller 12, and a charging device 13 including a charging roller,
A cleaning (not shown) device and the like are housed in a case as one kit to form a single unit. A scanner unit 22 including a laser emitting section 23, a lens 24, a reflecting mirror 25, and the like is arranged above the image forming unit 7, and below the transfer unit table 8 the charging device 13 and the transfer roller 9 are arranged. A high voltage substrate 26 for applying a high voltage is arranged, and a control substrate 27 is arranged below the fixing device 15.
【0010】帯電装置13にて予め帯電させた感光体ド
ラム10の表面に、図示しないホストコンピュータ等の
外部機器から伝送された画像データに応じて、スキャナ
ユニット22から発射された光を照射して、感光体ドラ
ム10の表面に静電潜像を形成し、次いで、現像ローラ
12を回転して帯電させた粉体状のトナーの供給により
前記潜像を可視像化するという現像を実行した後、この
感光体ドラム10と転写ローラ9との間の転写部位に供
給された用紙Pに前記トナー像を転写する。次に、電気
絶縁性を有する合成樹脂製の転写ユニット台8表面側
(上側)のフイン状の通過ガイド部材32上を滑って搬
送される用紙Pは、定着装置15における加熱ローラ1
6と押圧ローラ17との間(定着部位)を通過して、前
記転写されたトナー像に熱及び圧力を付加して用紙Pに
トナー像を定着させる。その後、その用紙Pは排紙ガイ
ド板18、中間ローラ対19、排紙ローラ対20を介し
て装置本体2上面の用紙トレイ21に排紙されるもので
ある。The surface of the photosensitive drum 10 precharged by the charging device 13 is irradiated with light emitted from the scanner unit 22 in accordance with image data transmitted from an external device such as a host computer (not shown). The electrostatic latent image is formed on the surface of the photoconductor drum 10, and then the developing roller 12 is rotated to supply the charged powdery toner to visualize the latent image. After that, the toner image is transferred onto the paper P supplied to the transfer site between the photoconductor drum 10 and the transfer roller 9. Next, the paper P that is conveyed by sliding on the fin-shaped passage guide member 32 on the surface side (upper side) of the transfer unit base 8 made of synthetic resin having electric insulation is the heating roller 1 in the fixing device 15.
The toner image is fixed on the paper P by passing heat and pressure to the transferred toner image after passing between the roller 6 and the pressing roller 17 (fixing portion). After that, the paper P is discharged to the paper tray 21 on the upper surface of the apparatus main body 2 via the paper discharge guide plate 18, the intermediate roller pair 19, and the paper discharge roller pair 20.
【0011】次に、定着装置15の構成について、図2
〜図5を参照しながら詳述すると、定着装置15の本体
ケースは、図5に示すように、前記加熱ローラ16及び
押圧ローラ17を上下から覆うようにした上下一対のケ
ース36,35から構成されている。実施例では、前記
加熱ローラ16及び押圧ローラ17の各々の左右両端の
軸受部を支持する左右一対の支持側板35a,35aを
備えた下ケース35と、前記加熱ローラ16の上方を覆
い、且つ下ケース35に対して着脱自在な上ケース36
とにより構成し、上下ケース36,35は各々エポキシ
樹脂、フェノール樹脂、ユリア樹脂、メラミン樹脂、A
BS樹脂等の電気絶縁性且つ耐熱性合成樹脂を射出成形
にて一体的に形成したものである。Next, the structure of the fixing device 15 is shown in FIG.
As described in detail with reference to FIG. 5, the main body case of the fixing device 15 is composed of a pair of upper and lower cases 36 and 35 that cover the heating roller 16 and the pressing roller 17 from above and below, as shown in FIG. Has been done. In the embodiment, a lower case 35 having a pair of left and right supporting side plates 35a and 35a for supporting bearings at the left and right ends of the heating roller 16 and the pressing roller 17, respectively, and a lower case 35 which covers the upper side of the heating roller 16 and Upper case 36 that is detachable from the case 35
The upper and lower cases 36 and 35 are made of epoxy resin, phenol resin, urea resin, melamine resin, and A, respectively.
An electrically insulating and heat resistant synthetic resin such as BS resin is integrally formed by injection molding.
【0012】下ケース35における左右一対の支持側板
35a,35aには、図2及び図5に示すように、下側
の押圧ローラ17の左右両側端の軸受37(図3で一方
のみ示す)を上下動自在に案内する長溝38と、加熱ロ
ーラ16の略円筒状の軸受部材39,39が嵌まる大径
の軸受孔40とが連続状に形成されており、前記軸受3
7を図示しないコイルバネにて上向きに押すことによ
り、押圧ローラ17の上面が加熱ローラ16の下面に押
圧されるように構成されている。As shown in FIGS. 2 and 5, bearings 37 (only one of which is shown in FIG. 3) on both left and right sides of the lower pressing roller 17 are provided on the pair of left and right supporting side plates 35a, 35a of the lower case 35. A long groove 38 that guides vertically and a large-diameter bearing hole 40 into which the substantially cylindrical bearing members 39, 39 of the heating roller 16 are fitted are continuously formed.
By pushing 7 upward with a coil spring (not shown), the upper surface of the pressing roller 17 is pressed against the lower surface of the heating roller 16.
【0013】押圧ローラ17の前後部位を挟み且つその
軸線とほぼ平行状に延びる上流側ガイド板41と下流側
ガイド板42との左右両側端部は、図5に示すように、
前記左右一対の支持側板35a,35aに一体的に連設
されている。上流側ガイド板41における複数のフイン
部41aは、図5に示すように、押圧ローラ17の軸線
方向に適宜間隔にて立設され、各フイン部41aの上端
縁は、図4に示すように、前端(用紙Pの搬送方向上流
側)が低く、押圧ローラ17の周面に接近するにつれて
定着部位Aに近くなるように傾斜している。同様にし
て、下流側ガイド板42における複数のフイン部42a
は押圧ローラ17の軸線方向に適宜間隔にて立設され、
各フイン部44aの上端縁は前端が定着部位Aに近い低
い位置で、押圧ローラ17から離れるにつれて(用紙P
の搬送方向下流側)加熱ローラ16の上面とほぼ同じ高
さ位置になるように傾斜している。As shown in FIG. 5, the left and right ends of the upstream guide plate 41 and the downstream guide plate 42 that sandwich the front and rear portions of the pressing roller 17 and extend substantially parallel to the axis thereof are as shown in FIG.
The pair of left and right supporting side plates 35a, 35a are integrally connected. As shown in FIG. 5, the plurality of fin portions 41a of the upstream guide plate 41 are erected at appropriate intervals in the axial direction of the pressing roller 17, and the upper end edges of each fin portion 41a are set as shown in FIG. The front end (upstream side of the sheet P in the conveying direction) is low and is inclined so as to be closer to the fixing portion A as it approaches the peripheral surface of the pressing roller 17. Similarly, the plurality of fin portions 42a in the downstream guide plate 42
Are erected at appropriate intervals in the axial direction of the pressing roller 17,
The upper edge of each fin portion 44a is at a lower position where the front end is closer to the fixing portion A, and as the distance from the pressing roller 17 increases (the paper P
(Downstream side in the transport direction of), the heating roller 16 is inclined so as to be at substantially the same height as the upper surface of the heating roller 16.
【0014】加熱ローラ16は、アルミ等の熱伝導性の
高い材料からなる筒部の外周にシリコーン樹脂や珪素樹
脂等のゴム弾性を有する弾性層と、その表面の離型性樹
脂表面層(ポリテトラフルオロエチレン、パーフルオロ
アルコキシ−チトラフルオロエチレン共重合体等)とを
有している。この離型性樹脂表面層により、定着時に用
紙Pに軟化して定着されたトナーが再度加熱ローラ16
の表面に転写される、いわゆるオフセット現象を防止で
きるものである。The heating roller 16 has an elastic layer having rubber elasticity such as silicone resin or silicon resin on the outer periphery of a cylindrical portion made of a material having high thermal conductivity such as aluminum, and a releasable resin surface layer (polyester) on the surface thereof. Tetrafluoroethylene, perfluoroalkoxy-chitrafluoroethylene copolymer, etc.). The release resin surface layer softens the toner fixed on the paper P at the time of fixing to the heated roller 16 again.
It is possible to prevent the so-called offset phenomenon that is transferred to the surface of.
【0015】前記上ケース36には、図5に示すよう
に、前記加熱ローラ16の内径部に配置するハロゲンラ
ンプ等の直線状(筒状)のヒータ体43の左右両側端部
を覆う下向きの側カバー部36b,36bが天板36a
の左右両側端から下向きに延びるように一体的に設られ
ている。また、前記ヒータ体43の左右両側端部は、図
2に示すように、筒状の加熱ローラ16の左右両側端か
ら外に適宜寸法だけ突出しており、ヒータ体43の左右
両側端部における電極端子43a,43aに電気的に接
続させて電力を供給するための一対のホルダ46,46
は、側面視横向きL字状に形成されたばね弾性を有する
金属板から形成され、両ホルダ46,46の水平部基端
を上ケース36における天板36a下面にネジ47にて
固定する。そして、左右両ホルダ46,46の下端を内
向きに屈曲させた接触部46a,46aをヒータ体43
の左右両電極端子43a,43aの凹端面部に弾性的に
押圧接触させて支持するものである。As shown in FIG. 5, the upper case 36 has a downward facing surface which covers both left and right end portions of a linear (cylindrical) heater body 43 such as a halogen lamp arranged inside the heating roller 16. The side cover portions 36b and 36b are top plates 36a.
Are integrally provided so as to extend downward from both left and right ends. Further, as shown in FIG. 2, the left and right end portions of the heater body 43 project outward from the left and right end portions of the tubular heating roller 16 by an appropriate dimension, and the electrodes at the left and right end portions of the heater body 43 are protruded. A pair of holders 46, 46 for electrically connecting to the terminals 43a, 43a to supply electric power
Is formed from a metal plate having a spring elasticity formed laterally in an L shape in a side view, and the base ends of the horizontal portions of both holders 46, 46 are fixed to the lower surface of the top plate 36a of the upper case 36 with screws 47. The contact portions 46a, 46a in which the lower ends of the left and right holders 46, 46 are bent inward are attached to the heater body 43.
The left and right electrode terminals 43a, 43a are elastically pressed into contact with and supported by the concave end surface portions.
【0016】なお、上ケース36の天板36aの上面に
露出させた前記ネジ47の箇所等の給電部から図示しな
い配線を介して外部の電力回路に接続させることによ
り、電子回路からヒータ体43に電力を供給することが
できる。また、前記上ケース36には、隣接する画像形
成ユニット7の後端に対峙するようにした複数枚の防熱
壁44,45が加熱ローラ16の軸線に沿って上ケース
36における天板36aから下向きに延び、少なくとも
加熱ローラ16の円周の上半部を覆うように一体的に形
成されている(図4参照)。他の実施例としては防熱壁
の枚数を3枚以上にしても良く、前記各実施例におい
て、防熱壁間と天板36aとで囲まれるようにした空気
溜まり56を設けることが好ましい。The heater body 43 is connected from the electronic circuit by connecting a power feeding portion such as the screw 47 exposed on the upper surface of the top plate 36a of the upper case 36 to an external power circuit through a wiring (not shown). Can be powered. Further, in the upper case 36, a plurality of heat insulating walls 44 and 45 facing the rear end of the adjacent image forming unit 7 face downward from the top plate 36a of the upper case 36 along the axis of the heating roller 16. And is integrally formed so as to cover at least the upper half of the circumference of the heating roller 16 (see FIG. 4). As another embodiment, the number of heat insulating walls may be three or more, and in each of the above embodiments, it is preferable to provide an air reservoir 56 surrounded by the heat insulating walls and the top plate 36a.
【0017】さらに、上ケース36のうち用紙Pの搬送
方向下流側には、用紙剥離ガイド部材48が天板36a
から下向きに延び、加熱ローラ16の後側周面に下端縁
部48aが隙間0.2mm〜0.5mm程度で近接する
ように配置するように一体的に設けられている(図4参
照)。この用紙剥離ガイド部材48は加熱ローラ16の
軸線と平行状であって、且つ加熱ローラ16の長さとほ
ぼ同じ長さを有している。Further, on the downstream side of the upper case 36 in the conveying direction of the paper P, a paper peeling guide member 48 is provided on the top plate 36a.
Downwardly, the lower end edge portion 48a is integrally provided on the rear peripheral surface of the heating roller 16 so as to be close to the heating roller 16 with a gap of about 0.2 mm to 0.5 mm (see FIG. 4). The sheet peeling guide member 48 is parallel to the axis of the heating roller 16 and has substantially the same length as the heating roller 16.
【0018】そして、図4に示すように、上ケース36
の天板36a下面には、前記用紙剥離ガイド部材48に
下端縁が連設されて上向き凸状の湾曲するリブ50を加
熱ローラ6の軸線方向に適宜間隔にて複数箇所で下向き
に突設されている。なお、上ケース36のうち用紙Pの
搬送方向下流側には、前記リブ50の下端縁よりも下位
置に下周面を有する遊びコロ51を軸52に回転自在に
複数配置している。Then, as shown in FIG.
On the lower surface of the top plate 36a of the sheet peeling guide member 48, a rib 50 having a lower end edge continuous with the sheet peeling guide member 48 and curved in an upward convex shape is provided so as to project downward at a plurality of positions at appropriate intervals in the axial direction of the heating roller 6. ing. A plurality of play rollers 51 having a lower peripheral surface below the lower end edges of the ribs 50 are rotatably arranged on a shaft 52 on the downstream side of the upper case 36 in the conveyance direction of the paper P.
【0019】これらの構成により、定着時に加熱ローラ
16の円周面にほぼ沿ってカールする用紙Pの先端が用
紙剥離ガイド部材48の下端縁部48aにて剥離され、
次いでリブ50の下端縁に用紙Pの先端が摺接しつつ搬
送下流側に送られる。そして、用紙Pの先端が中間ロー
ラ対19に挟持されて給送されるとき、加熱ローラ16
の円周面と同じ方向に湾曲している用紙Pの上面(トナ
ーが定着された面)は上向きに凸状のリブ50の下端縁
には摺接しない。しかも、自由に回転する遊びコロ51
の円周面に沿って円滑に給送されるから用紙P上面のト
ナーが定着後に剥離しないし、リブ50の縁や遊びコロ
51の円周面にも付着しないから画像の質を悪化させな
いのである。With these configurations, the leading edge of the paper P curled substantially along the circumferential surface of the heating roller 16 at the time of fixing is peeled off at the lower end edge portion 48a of the paper peeling guide member 48,
Next, the leading edge of the sheet P is slidably contacted with the lower edge of the rib 50 and is fed to the downstream side of the conveyance. When the leading edge of the paper P is nipped by the intermediate roller pair 19 and fed, the heating roller 16
The upper surface (the surface on which the toner has been fixed) of the paper P, which is curved in the same direction as the circumferential surface of, does not slidably contact the lower edge of the upwardly convex rib 50. Moreover, the play roller 51 that rotates freely
The toner on the upper surface of the paper P is not peeled off after being fixed because it is smoothly fed along the circumferential surface of the sheet P, and the toner does not adhere to the edge of the rib 50 or the circumferential surface of the play roller 51, so that the image quality is not deteriorated. is there.
【0020】上述のように、2つに分割された下ケース
35と上ケース36とは、下ケース35に予め押圧ロー
ラ17と加熱ローラ16とを組み込む一方、上ケース3
6に遊びコロ51を取りつけた後、下ケース35におけ
る左右一対の支持側板35a,35aの上端面に前記上
ケース36の天板36aを載置して被せ、支持側板35
a,35aの上端部に形成された複数箇所の雌ねじ部5
3に対して上ケース36をねじ54にて締着すれば良い
(図5参照)。As described above, the lower case 35 and the upper case 36, which are divided into two, have the pressing roller 17 and the heating roller 16 incorporated in advance in the lower case 35, while the upper case 3
After attaching the play roller 51 to 6, the top plate 36a of the upper case 36 is placed on the upper end surfaces of the pair of left and right supporting side plates 35a, 35a of the lower case 35 to cover the supporting side plate 35.
female screw portions 5 formed at the upper ends of a and 35a
3, the upper case 36 may be fastened with screws 54 (see FIG. 5).
【0021】その後、上ケース36における左右両側カ
バー部36b,36bの下端に切欠き形成された取付け
凹所55,55の一方から棒状のヒータ体43を加熱ロ
ーラ16の内径部に差し込み、ヒータ体43の左右両端
の電極端子43a,43aの凹端面部に、前記左右両ホ
ルダ46,46の下端を内向きに屈曲させた接触部46
a,46aを弾性的に押圧接触させるように取付ければ
良い。Thereafter, the rod-shaped heater body 43 is inserted into the inner diameter portion of the heating roller 16 from one of the mounting recesses 55, 55 formed by cutting out at the lower ends of the left and right side cover portions 36b, 36b of the upper case 36, and the heater body is inserted. Contact portions 46 in which the lower ends of the left and right holders 46, 46 are bent inwardly on the concave end surface portions of the electrode terminals 43a, 43a at the left and right ends of 43, respectively.
It suffices that the a and 46a be attached so as to elastically press and contact.
【0022】なお、下ケース35における左右両支持側
板35a,35aの外面に基端を固着したホルダ(図示
せず)にて前記ヒータ体43の左右両電極端子43a,
43aを支持するようにしても良く、この場合には、下
ケース35に対する押圧ローラ17,加熱ローラ16及
びヒータ体43という必要部品の組み込みを完了させた
後、上ケース36を被せれば良いから、組立作業は一層
簡単になる。Both left and right electrode terminals 43a of the heater body 43 are attached by holders (not shown) whose base ends are fixed to the outer surfaces of the left and right supporting side plates 35a, 35a of the lower case 35.
43a may be supported. In this case, the upper case 36 may be covered after the necessary parts such as the pressing roller 17, the heating roller 16 and the heater body 43 have been assembled into the lower case 35. Assembling work becomes easier.
【0023】また、加熱ローラ16の一側外周面に従動
ギヤ57を固定し、上ケース36における前面の空間に
臨ませた図示しない駆動側ギヤから回転力が伝達される
ようにしている。このように組立完了した定着装置15
を、画像形成ユニット7の後端側に隣接して取付けすれ
ば、加熱ローラ16から発散される熱、特に輻射熱は、
前記上ケース36における複数枚の防熱壁44,45に
て遮断される。また、図4に示すように、複数の防熱壁
44,45と天板36a間に空気溜まり56を形成する
ことより、熱不良導体である空気の存在にて、断熱効果
を向上させることができ、画像形成ユニット7方向への
熱放射、熱対流を効果的に無くして、画像形成ユニット
7内のトナーの軟化を防止できて、プリンタ1の長時間
の作動によっても画質を悪化させることがない。Further, the driven gear 57 is fixed on the outer peripheral surface on one side of the heating roller 16 so that the rotational force is transmitted from the drive side gear (not shown) facing the front space of the upper case 36. The fixing device 15 thus assembled
Is attached adjacent to the rear end side of the image forming unit 7, heat radiated from the heating roller 16, especially radiant heat,
The upper case 36 is shielded by a plurality of heat insulating walls 44 and 45. Further, as shown in FIG. 4, by forming the air pocket 56 between the plurality of heat insulating walls 44, 45 and the top plate 36a, the heat insulating effect can be improved in the presence of air which is a poor heat conductor. The heat radiation and heat convection in the direction of the image forming unit 7 can be effectively eliminated, the toner in the image forming unit 7 can be prevented from softening, and the image quality does not deteriorate even when the printer 1 is operated for a long time. .
【0024】前記実施例では加熱ローラ16を上側に配
置し、下側に押圧ローラ17を配置した形態であった
が、これに代えて、加熱ローラ16を下ケース35に装
着し、上ケース36に押圧ローラ17を装着した実施例
では、用紙Pのトナー像が形成される面が下面であるか
ら、前記下ケースにおいて加熱ローラ16より用紙搬送
下流側に用紙剥離部材48をその縁が上向きとなるよう
に下流側ガイド板42の箇所に一体的に形成すれば良
い。また、下流側ガイド板42における複数のフイン部
42aの上縁の側面視形状を下向き凸状に形成すること
により、前記実施例におけるリブ50と同様の作用・効
果を奏することができる。この場合、遊びコロ51を前
記フイン部42aの後部寄り部位に配置できることはい
うまでもない。In the above embodiment, the heating roller 16 is arranged on the upper side and the pressing roller 17 is arranged on the lower side, but instead of this, the heating roller 16 is mounted on the lower case 35 and the upper case 36. In the embodiment in which the pressing roller 17 is mounted on the paper P, the surface of the paper P on which the toner image is formed is the lower surface. Therefore, in the lower case, the edge of the paper peeling member 48 is located downstream of the heating roller 16 in the paper conveyance direction. It may be integrally formed at the location of the downstream guide plate 42 so that Also, by forming the side view shape of the upper edges of the plurality of fin portions 42a of the downstream guide plate 42 in a downward convex shape, it is possible to achieve the same operation and effect as the rib 50 in the above-described embodiment. In this case, it is needless to say that the play roller 51 can be arranged at the rear portion of the fin portion 42a.
【0025】本発明は、ファクシミリや複写機等の静電
電子写真式画像形成装置における定着装置にも適用でき
ることはいうまでもない。Needless to say, the present invention can be applied to a fixing device in an electrostatic electrophotographic image forming apparatus such as a facsimile or a copying machine.
【0026】[0026]
【発明の作用・効果】以上に説明したように、請求項1
記載の発明の画像形成装置の定着装置は、ほぼ水平な回
転軸線回りに回転する加熱ローラと押圧ローラとによ
り、トナー像が転写された用紙等の被記録媒体に熱と圧
力を付与してトナー像を定着させるように構成し、該定
着装置の本体ケースを、加熱ローラと押圧ローラとの外
周を覆うようにした上下2つのケースに分割し、加熱ロ
ーラの外周を覆う一方のケースには、加熱ローラの被記
録媒体搬送下流側周面に縁部が近接するように沿設した
用紙剥離ガイド部材を一体的に形成したものである。As described above, claim 1
The fixing device of the image forming apparatus according to the invention described above applies heat and pressure to a recording medium such as a sheet on which a toner image is transferred by a heating roller and a pressing roller that rotate around a substantially horizontal axis of rotation of the toner. The main body case of the fixing device is divided into two upper and lower cases configured to fix an image so as to cover the outer circumferences of the heating roller and the pressing roller, and one case covering the outer circumference of the heating roller is A paper peeling guide member is integrally formed along the peripheral surface of the heating roller on the downstream side of the recording medium conveyance so that the edge portion is close to the peripheral surface.
【0027】従って、予め用紙剥離部材が一体的に形成
されたケースに、加熱ローラを装着するだけで、当該加
熱ローラの被記録媒体搬送下流側周面に縁部が近接する
ように配置することができ、定着装置の組立作業が至極
簡単になると共に、製造コストも低減できるという効果
を奏する。また、請求項2記載の画像形成装置の定着装
置は、請求項1記載の構成の他、一方のケースには、加
熱ローラの周面に近接した前記用紙剥離ガイド部材の縁
部から被記録媒体搬送下流側に向かって縁が延びるリブ
を突設し、該リブの縁を、加熱ローラの周面と逆向きに
湾曲するように形成したものであるから、被記録媒体が
加熱ローラに押圧されて湾曲する方向と逆向きに湾曲す
るリブの縁に対して被記録媒体のトナー付着面が擦れる
ことが全くなくなり、画質の悪化がないと言う効果を奏
すると共に、用紙剥離ガイド部材に対してリブが交叉す
る方向に延びるから、熱の影響で変形し易い用紙剥離ガ
イド部材の位置をリブにて拘束できて、用紙剥離ガイド
部材の縁部と加熱ローラの周面との隙間の変動も少なく
でき、ケースに別体で用紙剥離ガイド部材を取り付けす
る手間が省けて、製造コストを低減できると共に、ケー
スの一体形成の効果を一層高めることができるという効
果を奏する。Therefore, only by mounting the heating roller in the case where the paper peeling member is integrally formed in advance, the edge of the heating roller can be arranged close to the peripheral surface of the recording medium conveying downstream side. As a result, the assembly work of the fixing device becomes extremely simple, and the manufacturing cost can be reduced. Further, the fixing device of the image forming apparatus according to a second aspect has the structure according to the first aspect, and in one case, a recording medium is provided from an edge portion of the paper peeling guide member near a peripheral surface of the heating roller. Since a rib having an edge extending toward the downstream side of the conveyance is provided in a protruding manner and the edge of the rib is formed to be curved in a direction opposite to the peripheral surface of the heating roller, the recording medium is pressed against the heating roller. The toner adhering surface of the recording medium is not rubbed against the edge of the rib curving in the direction opposite to the curving direction, and the image quality is not deteriorated. Since they extend in the intersecting direction, the position of the paper peeling guide member, which is easily deformed by the influence of heat, can be restrained by the rib, and the fluctuation of the gap between the edge of the paper peeling guide member and the peripheral surface of the heating roller can be reduced. , Separate the paper in the case And eliminates the need to attach the guide member, the manufacturing cost can be reduced, an effect that can be further enhanced the effect of integral formation of the case.
【0028】更に、請求項3記載の発明の画像形成装置
の定着装置は、請求項1または請求項2記載の構成の
他、一方のケースには、用紙剥離ガイド部材の縁部から
被記録媒体搬送下流側に適宜離れた位置に、被記録媒体
が当接する遊びコロを回転自在に設けたものであるか
ら、被記録媒体の搬送下流側で当該被記録媒体の搬送方
向を変える場合に、被記録媒体における画像形成面がケ
ースの端部等に直接接触せず、回転する遊びコロの周面
と一体的に移動するのでトナーの剥げ落ち等にように画
質の悪化を防止することができるという効果を奏するの
である。Further, the fixing device of the image forming apparatus according to the third aspect of the present invention has the structure according to the first aspect or the second aspect, and in one case, the recording medium from the edge of the paper peeling guide member is provided. Since a play roller for contacting the recording medium is rotatably provided at a position appropriately separated on the downstream side of the conveyance, when changing the conveyance direction of the recording medium on the downstream side of the conveyance of the recording medium, The image forming surface of the recording medium does not come into direct contact with the end of the case or the like, and moves integrally with the peripheral surface of the rotating idler roller, so that it is possible to prevent deterioration of image quality such as toner peeling. It has an effect.
【0029】このように、前記いずれの発明において
も、画像形成装置を長時間作動させても画質の劣化が生
じず、綺麗な画像を形成することができるという効果を
奏するのである。As described above, in any of the above-mentioned inventions, even if the image forming apparatus is operated for a long time, the image quality is not deteriorated and a beautiful image can be formed.
【図1】レーザプリンタの概略側断面図である。FIG. 1 is a schematic side sectional view of a laser printer.
【図2】定着装置の縦断面図である。FIG. 2 is a vertical cross-sectional view of a fixing device.
【図3】図2の III−III 線矢視側面図である。FIG. 3 is a side view taken along the line III-III of FIG.
【図4】図2のIV−IV線矢視側断面図である。4 is a sectional view taken along the line IV-IV in FIG.
【図5】下ケース及び上ケースの斜視図である。FIG. 5 is a perspective view of a lower case and an upper case.
1 プリンタ 2 本体ケース 7 画像形成ユニット 8 転写ユニット台 10 感光体ドラム 15 定着装置 16 加熱ローラ 17 押圧ローラ 35 下ケース 35a 支持側板 36 上ケース 36a 天板 36b 側カバー部 41 上流側ガイド板 32 下流側ガイド板 43 ヒータ体 44,45 防熱壁 48 用紙剥離ガイド部材 48a 下端縁部 50 リブ 51 遊びコロ P 用紙 1 Printer 2 Main Body Case 7 Image Forming Unit 8 Transfer Unit Base 10 Photosensitive Drum 15 Fixing Device 16 Heating Roller 17 Pressing Roller 35 Lower Case 35a Support Side Plate 36 Upper Case 36a Top Plate 36b Side Cover Part 41 Upstream Side Guide Plate 32 Downstream Side Guide plate 43 Heater body 44, 45 Heat shield wall 48 Paper peeling guide member 48a Lower end edge portion 50 Rib 51 Play roller P Paper
Claims (3)
ローラと押圧ローラとにより、トナー像が転写された用
紙等の被記録媒体に熱と圧力を付与してトナー像を定着
させるように構成した画像形成装置の定着装置におい
て、該定着装置の本体ケースを、前記加熱ローラと押圧
ローラとの外周を覆うようにした上下2つのケースに分
割し、加熱ローラの外周を覆う一方のケースには、加熱
ローラの被記録媒体搬送下流側周面に縁部が近接するよ
うに沿設した用紙剥離ガイド部材を一体的に形成したこ
とを特徴とする画像形成装置の定着装置。1. A heating roller and a pressing roller that rotate around a substantially horizontal axis of rotation apply heat and pressure to a recording medium such as paper on which the toner image is transferred to fix the toner image. In the fixing device of the image forming apparatus, the main body case of the fixing device is divided into two upper and lower cases that cover the outer circumferences of the heating roller and the pressing roller, and one case that covers the outer circumference of the heating roller is divided into two cases. A fixing device for an image forming apparatus, wherein a paper peeling guide member is integrally formed along an outer peripheral surface of a heating roller on a downstream side of a recording medium conveyance so as to have an edge portion close thereto.
の周面に近接した前記用紙剥離ガイド部材の縁部から被
記録媒体搬送下流側に向かって縁が延びるリブを突設
し、該リブの縁を、加熱ローラの周面と逆向きに湾曲す
るように形成したことを特徴とする請求項1記載の画像
形成装置の定着装置。2. A rib extending from an edge portion of the paper peeling guide member near the peripheral surface of the heating roller toward the downstream side of the recording medium conveyance is provided in the one case so as to project therefrom. The fixing device for an image forming apparatus according to claim 1, wherein the edge of the fixing roller is formed so as to be curved in a direction opposite to the peripheral surface of the heating roller.
イド部材の縁部から被記録媒体搬送下流側に適宜離れた
位置に、被記録媒体が当接する遊びコロを回転自在に設
けたことを特徴とする請求項1または請求項2記載の画
像形成装置の定着装置。3. A play roller on which the recording medium abuts is rotatably provided in the one case at a position appropriately separated from the edge of the paper peeling guide member to the downstream side of the recording medium conveyance. A fixing device for an image forming apparatus according to claim 1 or 2.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13457494A JP3311147B2 (en) | 1994-06-16 | 1994-06-16 | Fixing device for image forming device |
US08/490,789 US5528345A (en) | 1994-06-16 | 1995-06-15 | Fixing device having heat roller and pressure roller for use in image recording apparatus |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13457494A JP3311147B2 (en) | 1994-06-16 | 1994-06-16 | Fixing device for image forming device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH086415A true JPH086415A (en) | 1996-01-12 |
JP3311147B2 JP3311147B2 (en) | 2002-08-05 |
Family
ID=15131540
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP13457494A Expired - Fee Related JP3311147B2 (en) | 1994-06-16 | 1994-06-16 | Fixing device for image forming device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3311147B2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2008033295A (en) * | 2006-06-29 | 2008-02-14 | Oki Data Corp | Fixing device and image forming apparatus having the same |
US7725053B2 (en) | 2004-07-12 | 2010-05-25 | Brother Kogyo Kabushiki Kaisha | Fixing unit having heater roller and pressure roller supports and image-forming device using the same |
US7796930B2 (en) | 2006-03-31 | 2010-09-14 | Kabushiki Kaisha Toshiba | Anti-toner-adhesion mechanism and sheet conveying apparatus and method thereof |
US8792814B2 (en) | 2009-03-10 | 2014-07-29 | Fuji Xerox Co., Ltd. | Releasing device, fixing device and image forming apparatus |
-
1994
- 1994-06-16 JP JP13457494A patent/JP3311147B2/en not_active Expired - Fee Related
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7725053B2 (en) | 2004-07-12 | 2010-05-25 | Brother Kogyo Kabushiki Kaisha | Fixing unit having heater roller and pressure roller supports and image-forming device using the same |
US7796930B2 (en) | 2006-03-31 | 2010-09-14 | Kabushiki Kaisha Toshiba | Anti-toner-adhesion mechanism and sheet conveying apparatus and method thereof |
JP2008033295A (en) * | 2006-06-29 | 2008-02-14 | Oki Data Corp | Fixing device and image forming apparatus having the same |
US8792814B2 (en) | 2009-03-10 | 2014-07-29 | Fuji Xerox Co., Ltd. | Releasing device, fixing device and image forming apparatus |
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