JPS5816274A - Fixing device - Google Patents

Abstract

PURPOSE:To make the extension of copying paper due to moisture absorption at the center part different from that at end parts, and to prevent the copying paper from being crinkled, by forming the lengthwise sectional shape of at least one of a couple of rollers of the fixing device of an electrophotographic copying machine in hyperbolas approximate to a straight line. CONSTITUTION:At least one fixing roller R of a couple of fixing roller of an electrophotographic copying machine has larger diameters at end parts than at the center part C, and its lengthwise sectional shape has a slope like a straight line approximate to hypebolas. Namely, the slope is shown by a straight line l1 from the left-side end part E of the roller R to a conversion point P1, a straight line l2 from the P1 to the conversion part P2 of the roller center part C, a straight line l3 from the point P2 to a right conversion point P3, and a straight line l4 from the conversion point P3 to the right end. Thus, the end part of copying paper extends more than the center part at high humidity, so a feed speed is decreased gradually toward the end parts of the roller R to prevent the generation of crinkles due to irregular extension without reference to the size of copying paper width, thereby manufacturing the roller easily without any trouble in forming accurate hyperbolas.

Description

【発明の詳細な説明】 本発明は、複写機あるいは記録装置等の画像形成機器の
定着装置であって、１対のローラの間に転写紙等のシー
トを通過させてシート上のトナー像を定着させる定着装
置に関するものである。更に詳細には、例えば、高湿度
雰囲気内でシート（以下、転写紙と称す）を処理する場
合や、両面処理の場合に発生しやすい転写紙のシワを防
止することのできる定着装置を提供するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device for an image forming device such as a copying machine or a recording device, which fixes a toner image on the sheet by passing a sheet such as transfer paper between a pair of rollers. The present invention relates to a fixing device that performs fixing. More specifically, the present invention provides a fixing device that can prevent wrinkles in transfer paper that tend to occur when processing a sheet (hereinafter referred to as transfer paper) in a high-humidity atmosphere or during double-sided processing, for example. It is something.

以下、複写機を例にあげて説明する。A copying machine will be explained below as an example.

まず、転写紙のしわは、定着装置に挾持される前の転写
紙の状態が平面状でない時に生じる。First, wrinkles in the transfer paper occur when the transfer paper is not in a flat state before being held by the fixing device.

例えば、高湿度環境内に積載されて放置された転写紙の
上から何枚かは全面にわたってほぼ均一に吸湿している
が、それより下方の紙は端部のみが吸湿し、中央部との
吸湿状態が異なっている。そのだめ、吸湿による紙の延
びが、中央部と端部とでは異なり、端部の延びが大きい
。For example, the top few sheets of transfer paper stacked and left in a high-humidity environment absorb moisture almost uniformly over the entire surface, but the paper below that absorbs moisture only at the edges, and there is no difference between the center and center. The moisture absorption state is different. Unfortunately, the elongation of the paper due to moisture absorption is different between the center and the edges, with the edge being more elongated.

このような転写紙がローラ対の間を通ると、延びの違い
を吸収できないために、しわが発生する。When such transfer paper passes between a pair of rollers, wrinkles occur because the difference in elongation cannot be absorbed.

この対策として、従来第１図に示す如く、ローラ対のい
ずれか一方又は両方の径を、端部Ｅの径をり、・中央部
Ｃの径をＤ２とした時、Ｄ、〉Ｄ２として、端部の送り
速度を中央部よりも速くする方法がとられてきた。As a countermeasure for this, conventionally, as shown in FIG. 1, the diameter of one or both of the roller pairs is the diameter of the end portion E, and the diameter of the center portion C is D2, then D,>D2. A method has been adopted in which the feed rate at the ends is faster than at the center.

しかしこの形状は、中央部Ｃ（径Ｄ２の位置）の紙が端
部基準で送られた場合には、基準側と他端とでは送り速
度が異なり、転写紙の延びに対応できなくなる。そのた
め、理想的にはローラの断面形状が双曲線の様な形状で
あることが望ましい。この様な曲線形状であれば、どの
様なサイズの転写紙が端部基準で送られても、転写紙は
その両端をほぼ同一の速度で送られることができるし、
また転写紙が不均一な平面状態にあった場合でも全面に
わたってしごきの効果があるために、しわを防止するこ
とができる。However, this shape cannot cope with the elongation of the transfer paper because, when the paper at the center C (diameter D2 position) is fed based on the end, the feeding speed differs between the reference side and the other end. Therefore, ideally, it is desirable that the cross-sectional shape of the roller be a hyperbolic shape. With such a curved shape, no matter what size transfer paper is fed based on the edge, the transfer paper can be fed at almost the same speed on both ends,
Furthermore, even if the transfer paper is in an uneven flat state, wrinkles can be prevented since the smoothing effect is exerted over the entire surface.

しかし実際、Ｄ、−Ｄ、が最大２００μ程度の範囲でこ
の様な理想的な双曲線を描くことは、実際上不可能であ
る。However, in reality, it is practically impossible to draw such an ideal hyperbola in a range where D and -D are approximately 200 μ at the maximum.

そこで本発明は、双曲線を直線によって近似することに
より、ローラの製造上の困難をなくすと共に、双曲線に
近い状態で転写紙の搬送を行うことができ、あらゆるサ
イズの転写紙に対して、しわの発生を防止することがで
きる定着装置を提供するものである。Therefore, by approximating a hyperbola with a straight line, the present invention eliminates the difficulties in manufacturing rollers, and allows transfer paper to be conveyed in a state close to a hyperbola, thereby eliminating wrinkles for transfer paper of all sizes. An object of the present invention is to provide a fixing device that can prevent this occurrence.

以下、図面を用いて本発明の一実施例について説明する
。An embodiment of the present invention will be described below with reference to the drawings.

第２図は本発明の一実施例で、図において、Ｒはローラ
でその形状を双曲線に近似させるために少なくとも外周
を形成する直線の傾きの変換点がＰｌ−Ｐ２・Ｐ３と３
カ所ある。即ちローラＲでは、その外周を形成する端部
Ｅ側直線１１はローラ中央部０へ向かうに従ってローラ
内部方向へ傾斜して変換点Ｐ１に達し、続いて直＋ｌ１
ｉｉ！１２は変換点Ｐ１からローラ中央部Ｃに位置する
変換点Ｐ２４でさらにローラ内部方向へ傾刷する。さら
に直線ｌ、は変換点Ｐ２からＰ３まで、また直線ｌ、は
変換点Ｐ３からローラ端部まで、それぞれローラ端部Ｅ
へ向かうに従ってローラ外部方向へ傾斜している。そこ
で本実施例では、ローラＲはローラＲ中央部０が最も細
く凹型の双曲線に近似した形状となっている。第３図に
本実施例のローラＲを用いた際、小サイズ紙が通過する
場合、ローラ対に先端が挾持された時の速度分布を示す
。本実施例では、他端に対して基準側（図中Ａで示す）
の搬送速度が大きく、転写紙Ｐはローラの軸線に対して
斜行し両端の速度が一致した状態で搬送される（第４図
）。FIG. 2 shows an embodiment of the present invention. In the figure, R is a roller, and in order to approximate its shape to a hyperbola, at least the conversion points of the slope of the straight line forming the outer circumference are Pl-P2・P3 and 3.
There are several places. That is, in the roller R, the end E side straight line 11 forming the outer periphery is inclined toward the inside of the roller as it goes toward the roller center 0, reaches the conversion point P1, and then straight +l1
ii! 12 is a conversion point P24 located at the center C of the roller from the conversion point P1, and the printing is further tilted toward the inside of the roller. Furthermore, the straight line l extends from the conversion point P2 to P3, and the straight line l extends from the conversion point P3 to the roller end E.
The roller is inclined toward the outside as it goes toward the outer surface of the roller. Therefore, in this embodiment, the roller R has a shape that approximates a concave hyperbola, with the central portion 0 of the roller R being the narrowest. FIG. 3 shows the speed distribution when the roller R of this embodiment is used, and when a small size paper passes, the leading end is held between the pair of rollers. In this example, the reference side (indicated by A in the figure) with respect to the other end is
The conveyance speed is high, and the transfer paper P is conveyed obliquely with respect to the axis of the roller, with the speeds at both ends being the same (FIG. 4).

この状態は、中央部に対して両端部の速度が速くその分
布も中央からふりわけでほぼ対称に近い。即ちフルサイ
ズ紙を通した時と同様の状態となり、転写紙の不均一な
延びに対してしわを防止することができる。In this state, the velocity at both ends is faster than that at the center, and the distribution also deviates from the center, making it almost symmetrical. That is, the state is the same as when full-size paper is passed through, and wrinkles can be prevented due to uneven stretching of the transfer paper.

また第５図に示す如く、定着ローラ１の金属パイプロー
ルで形成された芯金１１の形状を上述の形状とすると、
その表面に例えば四沸化エチレン等のトナーの非粘着性
物質１．を塗布すれば、このようにローラ形状が曲線状
であるということは、転写紙の搬送速度勾配が幅方向で
すべて異なるということであり、どの位置に於いても転
写紙を端部に引っばろうとするしごきの効果が生じ、転
写紙のどの位置での不均一な延びに対しても、しわを防
止できるさらなる改良となる。なお、２はヒータで、ロ
ーラ１周面を加熱する。Further, as shown in FIG. 5, if the shape of the core metal 11 formed by the metal pipe roll of the fixing roller 1 is the shape described above,
A non-tacky substance of the toner, such as tetrafluoroethylene, is applied to the surface.1. The fact that the roller shape is curved means that the transfer speed gradient of the transfer paper is different in the width direction, and if the transfer paper is pulled to the edge at any position, A smoothing effect is created, which is a further improvement in preventing wrinkles due to non-uniform stretching of the transfer paper at any location. Note that 2 is a heater that heats the circumferential surface of the roller 1.

さらに第６図に、第５図に示した定着ローラ１を用いた
定着装置の一実施例を示す。Further, FIG. 6 shows an embodiment of a fixing device using the fixing roller 1 shown in FIG. 5.

図において、１は前記実施例を用いた定着ローラで、剛
性金属パイプロール１７周面に四沸化エチレン樹脂等の
オフセット防止材の薄い被覆１２を有している。又定着
ローラ１の中空中にヒータ２が配置されており、とのヒ
ータによってローラｌはトナーを熱溶融定着可能な温度
に加熱される。５は加圧ローラで、剛性金属ロール３周
面にシリコーンゴム等オフセット防止性のある弾性材の
厚い被覆４を有している。この定着ローラ１と加圧ロー
ラ５は互いに圧接し、上記弾性被覆層４が弾性変形する
ことで紙Ｐの定着を行うニップ部を形成している。この
ローラ１，５の駆動は、モーター（図示せず）Ｋよって
ローラ１が矢印方向へ回転駆動され、またローラ５は摩
擦力によってローラ１に従動回転する。In the figure, reference numeral 1 denotes a fixing roller using the above-mentioned embodiment, which has a rigid metal pipe roll 17 and a thin coating 12 of an anti-offset material such as tetrafluoroethylene resin on the circumferential surface of the roll. Further, a heater 2 is disposed inside the fixing roller 1, and the roller 1 is heated to a temperature at which the toner can be thermally melted and fixed by the heater 2. Reference numeral 5 denotes a pressure roller, and the rigid metal roll 3 has a thick coating 4 of an elastic material such as silicone rubber having offset prevention properties on the circumferential surface thereof. The fixing roller 1 and the pressure roller 5 are in pressure contact with each other, and the elastic coating layer 4 is elastically deformed to form a nip portion in which the paper P is fixed. The rollers 1 and 5 are driven by a motor (not shown) K that rotates the roller 1 in the direction of the arrow, and the roller 5 rotates as a result of the roller 1 due to frictional force.

又、定着ローラ１の周面には、その表面をクリーニング
するウェブ７かり−ラ８によって圧接せしめられ、その
ウェブは回転自在の軸６から駆動力によって回転する軸
６Ｉまで移動して軸６、に巻き取られる。以上のロー２
１，５．８及び軸６，６１は定着器箱体１２に回転可能
に支持されている。Further, the circumferential surface of the fixing roller 1 is pressed against the circumferential surface of the fixing roller 1 by a web 7 or roller 8 that cleans the surface, and the web moves from the freely rotatable shaft 6 to the shaft 6I which is rotated by a driving force. is wound up. Row 2 above
1, 5.8 and shafts 6, 61 are rotatably supported by the fuser box 12.

電子写真複写機等の所定の画像形成法によって形成され
たトナー像Ｔを支持する紙Ｐは、搬送ベルト１３によっ
て搬送され、定着器箱体１２内に導かれる。次に案内部
材１４によって紙Ｐは、前述したローラｌとローラ５と
の成すニップ部へ導かれる。ここでトナー像Ｔは定着ロ
ーラ１によって熱溶融され、加圧ローラ５によって紙Ｐ
に定着せしめられる。この転写紙Ｐはニップ部通過後定
着ローラ】に粘着し、ローラ周面と共に移動し、定着ロ
ーラに圧接している分離爪１０（軸９を中心に回動し弾
性力によって定着ローラｌに圧接せしめられている）に
よってローラ１から分離される。そして案内板１１によ
って紙Ｐは排出ローラ対１５．１６に達し、これによっ
て画像形成装置の外へ導かれ軸１７を中心に回転可能な
ｌ・レイ１８に収納される。A paper P supporting a toner image T formed by a predetermined image forming method such as an electrophotographic copying machine is conveyed by a conveyor belt 13 and guided into a fixing device box 12 . Next, the paper P is guided by the guide member 14 to the nip formed by the roller 1 and the roller 5 described above. Here, the toner image T is thermally melted by the fixing roller 1, and the paper P is melted by the pressure roller 5.
be established in After passing through the nip, this transfer paper P sticks to the fixing roller, moves along with the roller circumferential surface, and is in pressure contact with the fixing roller.The separation claw 10 rotates around the shaft 9 and is pressed against the fixing roller L by elastic force. separated from the roller 1 by the Then, the paper P reaches a pair of ejection rollers 15 and 16 by the guide plate 11, and is thereby guided out of the image forming apparatus and stored in an L-ray 18 which is rotatable about a shaft 17.

一方、トナー像に接触する定着ローラ１の表面は、ロー
２１の回転方向と逆に移動するウェブ７によってクリー
ニングされ、定着が良好に行えるように保たれる。この
ウェブ７はローラ１の回転にさからってローラの一定回
転数ごとに少しづつ移動を繰り返し、新しいウェブがロ
ーラｌに圧接するようになっている。このウェブは移動
させないもので、ウェブが汚れた際に切シとるようなも
のでも良い。On the other hand, the surface of the fixing roller 1 that comes into contact with the toner image is cleaned by the web 7 that moves in the opposite direction to the rotational direction of the row 21, and is maintained so that good fixing can be performed. The web 7 moves against the rotation of the roller 1, little by little, at every constant rotational speed of the roller, so that a new web comes into pressure contact with the roller 1. This web does not need to be moved, and may be something that can be cut off when it becomes dirty.

この様に、前記実施例の定着ローラ１を用いることによ
って、しわの無い定着済み転写紙を得ることができる。In this way, by using the fixing roller 1 of the embodiment described above, it is possible to obtain a wrinkle-free fixed transfer paper.

なお転写紙Ｐが途中で詰まった場合、ローラ対１．５か
ら搬送方向に送り出された転写紙Ｐを装置外に取り出す
ために、分離爪１０と排出ローラ１５とを支持する板体
３６をバネ３５及び移動手段３４によって軸９を中心に
上方へ回転させると、転写紙Ｐの取り出しが更に容易に
なる。又、同様に排出ローラ１６と案内板１１を移動さ
せても良い。更に排出ローラ１５，１６を手動回転させ
て紙Ｐを取り出すようにしておくことも好ましい。Note that if the transfer paper P gets jammed on the way, in order to take out the transfer paper P sent out in the transport direction from the roller pair 1.5 out of the apparatus, the plate body 36 that supports the separation claw 10 and the ejection roller 15 is moved with a spring. 35 and the moving means 34 to rotate the transfer paper P upward about the shaft 9, it becomes easier to take out the transfer paper P. Further, the discharge roller 16 and the guide plate 11 may be moved in the same manner. Furthermore, it is also preferable to take out the paper P by manually rotating the discharge rollers 15 and 16.

また前記実施例の定着装置では、定着ローラのみ双曲線
に近似させ１形状としたが、加圧ローラのみあるいは定
着ローラと加圧ローラともにこの様な形状としても良い
こと勿論である。Further, in the fixing device of the above embodiment, only the fixing roller is approximated to a hyperbola and has one shape, but it goes without saying that only the pressure roller or both the fixing roller and the pressure roller may have such a shape.

また本発明は所謂加熱定着装置のみならず、所謂加圧定
着装置にも適用できること勿論である。Further, the present invention can of course be applied not only to a so-called heat fixing device but also to a so-called pressure fixing device.

以上説明したように、本発明は転写紙のしわ防止に効果
のあるローラ断面の双曲線形状を直線で近似することに
より、製造の簡易化、精度の保証をはかり、双曲線と同
様の効果を出すことができる定着装置を提供するもので
ある。As explained above, by approximating the hyperbolic shape of the cross section of the roller, which is effective in preventing wrinkles in the transfer paper, with a straight line, the present invention simplifies manufacturing, guarantees accuracy, and achieves the same effect as a hyperbola. The present invention provides a fixing device that can perform the following steps.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来のしわ防止用ローラの側面図、第２図は本
発明の一実施例を用いたローラの側面図、第３図は端部
基準で送られた小サイズ紙がローラ対に挾持された時の
搬送速度分布を示した説明図、第４図はその転写紙が安
定状態で送られた時の搬送速度分布を示した説明図、第
５図は他の実施例である直線近似した双曲線形状の芯金
に四節化エチレンを塗布したローラの断面図、第６図は
本発明の一実施例を用いた定着ローラを有する定着装置
の断面図である。 図において、Ｒ・・・ローラ、Ｐｌ・Ｐ２・Ｐ３・・・
変換点、１・・定着ローラ、１１・・・芯金、１２・・
・非粘着性物質、２・・・ヒータ、５・・・加圧ロール
、１２・・・定着器箱体。 出　願　人　　キャノン株式会社Fig. 1 is a side view of a conventional wrinkle prevention roller, Fig. 2 is a side view of a roller using an embodiment of the present invention, and Fig. 3 is a side view of a roller pair of small-sized paper fed based on the edge. An explanatory diagram showing the conveyance speed distribution when the transfer paper is clamped, Fig. 4 is an explanatory diagram showing the conveyance speed distribution when the transfer paper is fed in a stable state, and Fig. 5 is an explanatory diagram showing the conveyance speed distribution when the transfer paper is fed in a stable state. FIG. 6 is a cross-sectional view of a roller in which a core metal having an approximate hyperbolic shape is coated with four-node ethylene, and FIG. 6 is a cross-sectional view of a fixing device having a fixing roller using an embodiment of the present invention. In the figure, R...Roller, Pl, P2, P3...
Conversion point, 1... Fixing roller, 11... Core metal, 12...
- Non-adhesive substance, 2... Heater, 5... Pressure roll, 12... Fixing device box. Applicant Canon Co., Ltd.

Claims (3)

【特許請求の範囲】[Claims] （１）　　ローラ対間を通過させてシート上のトナー像
を定着させる定着装置において、 上記ローラの少なく゛とも一方が長手方向断面形状を直
線により近似した双曲線となしだことを特徴とする定着
装置。(1) A fixing device that fixes a toner image on a sheet by passing it between a pair of rollers, wherein at least one of the rollers has a longitudinal cross-sectional shape that is a hyperbola approximated by a straight line. . （２）前記双曲線を近似する直線の勾配の変換点が少な
くとも３力所以上ある特許請求の範囲第（１）項に記載
の定着装置。(2) The fixing device according to claim (1), wherein the straight line approximating the hyperbola has at least three points of conversion of the gradient. （３）前記ローラは芯金が前記形状であシ、その表面に
四沸化エチレン等のトナーの非粘着性物質をコーティン
グした特許請求の範囲第（１）項に記載の定着装置。(3) The fixing device according to claim 1, wherein the roller has a core metal having the shape described above, and a surface of the roller is coated with a non-adhesive substance for toner such as tetrafluoroethylene.