JP3758500B2 - Endless belt, belt for image forming apparatus, and image forming apparatus - Google Patents

Description

この測定により、図１，２に示すチャートを得た。なお、図２は図１のII部分を拡大したものである。
【０１４５】
テレフタル酸（ＴＰＡ）のベンゼン環水素はカルボン酸がブタンジオールと結合している場合とビスフェノールＡ（ＢＰＡ）とで化学シフトが異なる。
【０１４６】
一般にＰＢＴ分子中のＴＰＡベンゼン環水素（ｄ）は、化１の通り４ヶとも等価であり、化学シフト８．０７にシングレットピークを示す。
【０１４７】
【化１】

【０１４８】
一方、化２の如くＰＣのＢＰＡと結合したＰＢＴのＴＰＡ中のベンゼン環水素は、化学シフトが変化し、水素（ｂ）は８．２５にダブレット，（ｃ）は８．１３にダブレットピークを示す。
【０１４９】
【化２】

【０１５０】
（ｄ）：｛（ｂ）＋（ｃ）｝の面積比により、ＰＢＴ分子中のＴＰＡと、ＰＣと結合しているＴＰＡの比を求めることができる。
【０１５１】
本例では面積比は（ｄ）：｛（ｂ）＋（ｃ）｝＝１００：｛０．４６５４＋０．５６３５｝≒９９．０１：０．９９となるので、ＰＢＴ構成単位１００ｍｏｌあたり、０．９９ｍｏｌのＴＰＡ（ＰＢＴ由来）−ＢＰＡ（ＰＣ由来）結合を有していることが解る。また、本樹脂組成物中には同量のブタンジオール（ＰＢＴ由来）−炭素（ＰＣ）結合が存在することが容易に推測できるので、合計でＰＢＴ構成単位１００ｍｏｌあたり１．９８ｍｏｌのＰＢＴ−ＰＣ結合が存在することが解る。
【０１５２】
化３の通り、ＰＢＴ構成単位（ブタンジオール＋ＴＰＡ）の式量は２２０なので、ＰＢＴ２２０００（２２０×１００ｍｏｌ）ｇあたり、１．９８ｍｏｌのＰＢＴ−ＰＣ結合が存在する。
【０１５３】
ＰＢＴ−ＰＣ結合１ｍｏｌあたりのＰＢＴの質量は約１１０００（２２０００／１．９８）と計算できる。
【０１５４】
本例ではＰＢＴとＰＣの重量比が７／３なので、ＰＢＴ−ＰＣ結合１ｍｏｌあたりの樹脂分（ＰＢＴ質量＋ＰＣ質量）は１６０００ｇ（１１０００／０．７）と求めることができる。
【０１５５】
【化３】

【０１５６】
（分子量）
本発明においては、結晶性樹脂、非晶性樹脂、重合触媒を加熱混練し、結晶性樹脂の分子鎖と、非晶性樹脂の分子鎖間に化学結合を生成し、且つ、樹脂組成物としての総合の分子量を維持あるいは増加させることで、得られるエンドレスベルトの物性向上が図れると考えられるので、分子量は高い方が好ましい。
【０１５７】
分子量の測定方法であるが、本発明のように共重合体が存在する場合には分子量の真値を求めることが難しい。
【０１５８】
そこで本発明では全ての樹脂をＧＰＣにより同一条件で測定し、ＰＳ換算重量平均分子量として得た値を共通の代表値として用いることとした。
【０１５９】
測定条件としては、試料２０ｍｇを０．５ｍｌの１，１，１，３，３，３−ヘキサフルオロ−２−プロパノールと０．２ｍｌのクロロホルムで一晩溶解し、さらに移動相の溶媒２５ｍｌを加え、０．２２μｍのフィルターにて濾過し、ＳＥＣ測定溶液とした。移動相を加えてから測定終了まで１２時間以内に行った。
【０１６０】
ＳＥＣ測定条件
溶媒 クロロホルム／酢酸：９９．５：０．５（ｖｏｌ／ｖｏｌ）
流速 １．０ｍｌ／分
注入量 ０．０２ｍｌ
カラム ＡＤ８０６Ｍ／Ｓ ２本（昭和電工社製）
カラム温度 ３０℃
検出器 ＵＶ ２５４ｎｍ
分子量５００（Ａ−５００）から２，８９０，０００（Ｆ−２８８）までの分子量の異なる単分散標準ポリスチレン（東ソー社製）１２試料用い、較正曲線を作成し、ポリスチレン換算の分子量を計算した。
【０１６１】
本手法で、結晶性樹脂と、非晶性樹脂と、重合触媒を加熱混練した後に得られる樹脂組成物のＰＳ換算重量平均分子量（Ｍｗ_３とする）の値としては、具体的には、結晶性樹脂の配合比率をＸ重量部，ポリスチレン（ＰＳ）換算重量平均分子量をＭｗ_１、非晶性樹脂の配合比率をＹ重量部，ＰＳ換算重量平均分子量をＭｗ_２として、
【０１６２】
【数２】

【０１６３】
であることが好ましく、
【０１６４】
【数３】

【０１６５】
であるとさらに好ましく、
【０１６６】
【数４】

【０１６７】
であると、十分に高い物性を得られるので特に好ましい。
【０１６８】
また、本発明においてはＭｗ_３が加熱混合によりＭｗ_１とＭｗ_２の算術平均値よりも高くなっていることが重要で、初めから高いＭｗ_１やＭｗ_２の樹脂を用いても、加熱混合時に分子量低下していては最終的なＭｗ_３が高くても良好な物性は期待できないと考えられるので、Ｍｗ_３の絶対値に特に制限はないが、それでも総合的観点からは高い方が好ましく、具体的にはＰＳ換算重量平均分子量で１３０，０００以上が好ましく、１４０，０００以上であるとさらに好ましく、１５０，０００以上であると特に好ましい。
【０１６９】
なお、重量平均分子量真値とＰＳ換算重量平均分子量の相関の例を挙げると、重量平均分子量４０，０００のＰＢＴを上記手法で測定するとＰＳ換算重量平均分子量１２２，０００の値が得られ、重量平均分子量２８，０００のＰＣを上記手法で測定するとＰＳ換算重量平均分子量６４，０００の値が得られることがわかっている。
【０１７０】
（分散形態）
一般に２種類の熱可塑性樹脂を溶融混合しても完全には混じり合わず、流動構造をとることが知られている。両熱可塑性樹脂の体積分率に大きな差がある場合は体積分率の大きい方が海で体積分率が小さい方が島の構造をとりやすく、体積分率の差が小さい場合は溶融粘度差が海島構造に影響をあたえ、溶融粘度の小さい方が海に、大きい方が島になりやすいと言われている。
【０１７１】
分散状態の確認手法に特に制限はなく、ＲｕＯ_４で染色後、超薄切片を作成しＴＥＭで観察するなど公知の方法を用いることができる。
【０１７２】
（エンドレスベルトの用途）
このエンドレスベルトの用途に特に制限はないが、寸法精度，耐屈曲性，引張破断伸など要求物性の厳しいＯＡ機器分野、特に機能部材には好適に用いることができる。このエンドレスベルトをシームレスベルト形状とした場合、割れ，伸びなど不具合が少ないので好適である。
【０１７３】
このエンドレスベルトは、例えば電子写真の中間転写ベルト、搬送転写ベルト、感光体ベルトとして好適に用いることができる。
【０１７４】
このエンドレスベルトには、必要に応じて側縁に沿って補強テープを貼着してもよい。補強テープとしては、２軸延伸ポリエステルテープがコスト、強度の点で好ましく、そのテープ幅は４ｍｍ以上２０ｍｍ以下が装置レイアウト状コンパクトになり好ましい。補強テープの厚みは、２０μｍ以上２００μｍ以下がフレキシブルを維持するため低テンションでエンドレスベルトが駆動できる点と耐クラック発生防止の点で好ましい。
【０１７５】
【実施例】
本発明を実施例、比較例を用いて、より具体的に説明する。
【０１７６】
（原料）
原料は下記のものを用い、配合割合は表１又は表２の通りとした。

（加熱混練）
各原料を、二軸混練押出機（ＩＫＧ（株）製 ＰＭＴ３２）を用いて材料ペレット化した。
【０１７７】
（エンドレスベルトの成形方法）
この材料ペレットを乾燥し、直径φ１８０ｍｍ、リップ幅１ｍｍの６条スパイラル型環状ダイ付き４０ｍｍφの押出機により、環状ダイ下方に溶融チューブ状態で押し出し、押し出した溶融チューブを、環状ダイと同一軸線上に支持棒を介して装着した外径１７０ｍｍの冷却マンドレルの外表面に接しめて冷却固化させつつ、次に、シームレスベルトの中に設置されている中子と外側に設置されているロールにより、シームレスベルトを円筒形に保持した状態で引き取りつつ３４０ｍｍ長の長さで輪切りにして表１記載の所定の厚み、滞留時間となるよう押出量、引き取り速度を調整し、直径１６９ｍｍの樹脂製シームレスベルトとした。
【０１７８】
成形温度，滞留時間などの条件は表１の通りとした。
【０１７９】
（評価）
評価は必要に応じ、エンドレスベルトを必要な大きさに切り開いて実施した。
・表面抵抗率 Ω
表面抵抗率は測定器により好適に測定できる領域が異なるので以下のように使い分けた。
【０１８０】
表面抵抗率が１〜１×１０^６Ωとなるサンプルは、ダイヤインスツルメント（株）製 ロレスタを使用し、２０ｍｍピッチにてベルト円周方向を測定した。
【０１８１】
表面抵抗率が１０^６〜１×１０^１３Ωとなるサンプルは、ダイヤインスツルメント（株）製 ハイレスタ（ＨＡ端子）を使用し、５００Ｖ、１０秒の条件にて２０ｍｍピッチにてベルト円周方向を測定した。
【０１８２】
表面抵抗率が１０^１３〜１×１０^１６Ωとなるサンプルは、アドバンテスト（株） 微小電流測定器Ｒ８３４０Ａ（ＪＩＳ電極）を使用し、５００Ｖ、１０秒の条件にて１００ｍｍピッチにてベルト円周方向を測定した。
【０１８３】
ＤＳＣ
セイコー電子工業（株）製ＳＳＣ−５２００（商品名）を使用し、昇温速度１０℃／ｍｉｎにて測定した。１つの試料を３００℃までＤＳＣ測定した後、室温まで、速度１０℃／ｍｉｎで冷却し、その後再度同一条件で第２回目のＤＳＣ測定を行い、第１回目の融解ピーク温度と第２回目の融解ピーク温度との差を求めた。
・エンドレスベルトとしての耐久性の評価
得られたエンドレスベルトを中間転写ベルト、搬送転写ベルト或いは感光体ベルトとして画像形成装置に搭載し、連続で画像出力をし、何枚出力した段階でエンドレスベルトにクラックが発生するかを評価した。
・耐屈曲性（耐折れ性）
ＪＩＳＰ−８１１５に準拠し、試験片を幅１５ｍｍ、長さ１００ｍｍの大きさに切断し、ＭＩＴ試験機にて折り曲げ速度１７５回／分、回転角度１３５°左右、引張り荷重１．５Ｋｇｆの条件にて破壊回数を測定した。
・引張り弾性率
ＩＳＯ Ｒ１１８４−１９７０に準拠し、試験片を幅１５ｍｍ、長さ１５０ｍｍに切断し、引張り速度１ｍｍ／ｍｉｎ、つかみ具間距離を１００ｍｍとした。
・厚み
東京精密（株）製のマイクロメータを用いてエンドレスベルトの円周方向２０ｍｍピッチにて測定した。
・体積固有抵抗（Ω・ｃｍ）
高抵抗計ハイレスタＨＲＳプローブ（ダイヤインスツルメンツ（株）社製）を用い、測定電圧１００Ｖ、測定時間１０秒でエンドレスベルトの円周方向２０ｍｍピッチにて測定した。
【０１８４】
〔実施例１〜７〕
ＰＢＴ，ＰＣ，テトラブチルチタネート，酢酸マグネシウム，熱安定剤を事前に１３０℃程度で予備乾燥し、その後に加熱混練し、材料ペレットを得た。
【０１８５】
このときの加熱混練条件を表１に示すものとし、混練機内での反応は抑制するようにした。
【０１８６】
この材料ペレットを押出成形してエンドレスベルトを製造した。
【０１８７】
なお、この押出成形機内で反応が好ましい程度に促進し、エンドレスベルトが得られるように、表１に示す押出成形条件とした。
【０１８８】
表１にエンドレスベルトの形態、特性を示す。
【０１８９】
〔比較例１〕
重合触媒を用いなかったこと以外は実施例１と同じ条件で得たエンドレスベルト。
【０１９０】
ＰＢＴは不純物としての樹脂中の金属分の影響を除去するために一度溶剤に溶解してカラムを用いて濾過し、しかる後に溶剤を除去したものを用いた。
【０１９１】
表１にこの比較例１，２のエンドレスベルトの形態、特性を示す。
【０１９２】
〔比較例２〕
海島構造が生じないように混練条件、押出条件を選定した。表１の比較例２に示す条件とすることにより、ＰＢＴとＰＣとが均一に分散した非海島構造のエンドレスベルトを製造した。
【０１９３】
【表１】

【０１９４】
表１の通り、本発明例に係るエンドレスベルトは、いずれも広い温度範囲にわたって引張弾性率が高く、ベルト耐久性にも優れ、屈曲性が良好である。これに対し、重合触媒を添加しなかった比較例１では、６万枚でクラック及び画像ズレが生じ、耐屈曲性が不足する。比較例２は、重合触媒を添加してはいるものの、混練及び成形時の温度が高目に設定され非海島構造となっているために、１回目と２回目のＤＳＣ融解温度差が大きく、そのために高温域（６０℃）での引張弾性率が小さい。そして、この結果、６万枚の複写により、エンドレスベルトの伸びによる画像ズレが生じた。
【０１９５】
【発明の効果】
以上の実施例及び比較例からも明らかな通り、本発明によると、広い温度範囲にわたって引張弾性率が高く、且つ耐屈曲性や耐薬品性及び成形寸法安定性に優れ、溶融混合時の反応による物性劣化を抑えたエンドレスベルトと、このエンドレスベルトを用いた画像形成装置用ベルトと、この画像形成装置用ベルトを用いた画像形成装置が提供される。
【図面の簡単な説明】
【図１】ＰＢＴとＰＣとの混合反応物のＮＭＲチャートである。
【図２】図１のII部分の拡大図である。
【図３】従来の中間転写装置の側面図である。
【符号の説明】
１ 感光ドラム
２ 帯電器
３ 露光光学系
４ 現像器
５ クリーナー
６ 導電性エンドレスベルト
７，８，９ 搬送ローラ[0001]
BACKGROUND OF THE INVENTION
The present invention is used for an endless endless belt excellent in physical properties such as molding dimensional stability and bending resistance, and an electrophotographic copying machine, a laser beam printer, a facsimile machine, and the like using the endless belt. The present invention relates to an image forming apparatus belt such as an intermediate transfer belt, a conveyance transfer belt, and a photosensitive belt, and an image forming apparatus including the image forming apparatus belt.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an image forming apparatus such as an OA apparatus, an electrophotographic system using a photoconductor and toner, and a toner jet system that directly transfers toner onto an endless belt without using a photoconductor are devised and put on the market. These devices include conductive belts, intermediate transfer belts, transfer transfer belts, transfer separation belts, charging tubes, developing sleeves, fixing belts, toner transfer belts, etc., regardless of the presence or absence of seams, conductive, semiconductive, insulating Endless belts controlled to various electrical resistances are used.
[0003]
For example, the intermediate transfer device is configured to once form a toner image on an intermediate transfer member and then transfer the toner to paper or the like. An endless belt made of a seamless belt is used for charging and discharging the toner on the surface layer of the intermediate transfer member. This seamless belt is set (conductive, semiconductive, insulated) with different surface electrical resistance and thickness direction electrical resistance (volume electrical resistance) for each machine model.
[0004]
The transport transfer device is configured to hold the paper once on the transport transfer body, transfer the toner from the photosensitive member onto the paper held on the transport transfer body, and further remove the paper from the transport transfer body by discharging. Has been. On the surface of the transport transfer body, an endless belt with or without a seam is used for charging or neutralizing paper. The endless belt is set to have different surface electrical resistance and thickness direction electrical resistance (volume electrical resistance) for each machine model as described above.
[0005]
FIG. 3 is a side view of an electrophotographic apparatus using an intermediate transfer belt made of a conventional endless belt. In the figure, 1 is a photosensitive drum and 6 is a conductive endless belt. 1 is an electrophotographic process unit including a charging device 2, an exposure optical system 3 using a semiconductor laser as a light source, a developing device 4 containing toner, and a cleaner 5 for removing residual toner. Is arranged. The conductive endless belt 6 is wound around the transport rollers 7, 8, and 9 and moves in the direction of the arrow in synchronization with the photosensitive drum rotating in the direction of the arrow.
[0006]
Next, the operation will be described. First, the surface of the photosensitive drum 1 rotating in the direction of arrow A is uniformly charged by the charger 2. Next, an electrostatic latent image corresponding to an image obtained by an image reading device (not shown) is formed on the photosensitive drum 1 by the optical system 3. The electrostatic latent image is developed into a toner image by the developing device 4. This toner image is electrostatically transferred to the conductive endless belt 6 by the electrostatic transfer machine 10 and transferred to the recording paper 11 between the conveying roller 9 and the pressing roller 12.
[0007]
By the way, in the case of a conductive endless belt of an image forming apparatus such as an electrophotographic copying machine, sufficient durability is required because it is driven with high tension for a long time by two or more rolls. Further, when used in an intermediate transfer device or the like, an image is formed with toner on a belt and transferred to paper, and if the belt is loosened or stretched during driving, image misalignment may occur. Further, since toner is transferred electrostatically, a certain degree of conductivity is also required.
[0008]
Such an endless belt is an important part that determines a toner image, and is considered to be one of the three important parts together with the photoreceptor and toner.
[0009]
Therefore, the following items (1) to (7) are required for the intermediate transfer belt.
(1) The semiconductor region has predetermined surface resistivity and volume resistivity.
(2) Toner releasability.
(3) The thickness is thin and uniform.
(4) Strong mechanical strength (hard to break).
(5) There should be little variation in resistance due to the environment (temperature and humidity).
(6) Low cost.
(7) The belt must be seamless and round.
[0010]
In addition, with the recent high-speed printing of machines, the driving speed of the belt has increased, and it has become necessary to improve the durability of the belt.
[0011]
In particular, attention is paid to the fact that printing can be performed at a high speed with a tandem type transport transfer, intermediate transfer belt or toner jet belt in which four photoconductors are arranged, and durability and image misalignment are particularly important.
[0012]
To date, carbon blacks such as acetylene black, furnace black, and channel black are added to resin compositions such as polyamide, polyimide, polyvinylidene fluoride, ethylene tetrafluoroethylene copolymer, polycarbonate, and polyester. This is formed into a thickness of about several tens to several hundreds of μm, and a belt set to a predetermined electrical resistivity (surface resistivity, volume resistivity) is used as an intermediate transfer belt, paper transport and toner transfer. It is known that a transfer and transfer belt is also obtained (JP-A-63-111267, JP-A-5-170946, JP-A-6-228335, etc.).
In addition, the following methods are considered as a manufacturing method of an endless belt.
[0013]
 (i) Rotational molding method (or sometimes expressed as centrifugal molding method)
Put the resin in which the solution is dissolved on the inner peripheral surface of the cylindrical mold, apply temperature while rotating the mold, volatilize the solvent by half or more, and then remove the seamless tube from the mold. And a step of attaching a seamless tube to the outside of the cylindrical mold and applying a temperature to cause a thermosetting reaction (JP-A-60-170862). This method is mainly used for manufacturing a polyimide transfer belt.
[0014]
(ii) Extrusion method
In this method, a resin compounded with a conductive filler is melt-extruded in a ring shape. This method is mainly used in a method for producing an ethylenetetrafluoroethylene copolymer, polyvinylidene fluoride, polycarbonate-based, polyester-based, or polyimide-based transfer belt.
 (iii) Dipping method
In this method, the resin solution is applied to the outer surface of a cylindrical or columnar mold by dipping or the like to form a fixed thickness, and after heating to form a film, the tubular film formed from the mold is pulled out. This method is mainly used for producing a transfer film made of polyvinylidene fluoride.
[0015]
(iv) Rubber extrusion molding method
A method has been reported in which polyurethane rubber is extruded and vulcanized into a cylindrical shape, and then surface-polished and coated with a fluororesin or the like on the surface of the outer layer again (Electrophotographic Society Journal 33 (1) 43 (1994)).
[0016]
Conventionally, as such a conductive endless belt, one formed by blending a thermosetting resin or a thermoplastic resin with a conductive filler such as carbon black has been mainly used. Among them, those mainly composed of a thermoplastic resin are easy to continuously form and have been widely used. Among the thermoplastic resins, the thermoplastic amorphous resin is more excellent in dimensional accuracy than the thermoplastic crystalline resin. As such an endless belt made of a thermoplastic amorphous resin, for example, a conductive carbon black is blended with a thermoplastic resin such as a polycarbonate resin, and is extruded into a cylindrical film using a cylindrical die. Is known (Japanese Patent Laid-Open No. 3-89357, etc.).
[0017]
However, the thermoplastic resin amorphous resin has better dimensional accuracy than the thermoplastic crystalline resin, but is inferior in bending resistance. For example, when used in electrophotography as an intermediate transfer belt, cracks occur during use. Cheap.
[0018]
In order to solve this problem, an endless belt in which a polycarbonate and a polyalkylene terephthalate such as polybutylene terephthalate are blended has been proposed (Japanese Patent Laid-Open Nos. 4-313757 and 6-149083).
[0019]
However, an endless belt formed by blending polycarbonate (hereinafter also referred to as PC) and polyalkylene terephthalate (hereinafter also referred to as PAT) such as polybutylene terephthalate (hereinafter also referred to as PBT). Although the bending resistance is improved as compared with the above endless belt made of polycarbonate, the effect of the improvement is still insufficient. Further, since the polyalkylene terephthalate resin has high crystallinity, the dimensional accuracy of the endless belt is lowered when the blending amount is increased.
[0020]
As a general knowledge, thermoplastic resins can be broadly classified into crystalline thermoplastic resins and amorphous thermoplastic resins. Crystalline thermoplastic resins are excellent in bending resistance and chemical resistance, but have high molding shrinkage. Therefore, dimensional stability is poor and it does not have transparency, and on the contrary, amorphous thermoplastic resin has excellent dimensional stability and transparency, but has problems such as poor bending resistance and poor chemical resistance. It has been said that
[0021]
However, in many cases, it is required to have excellent bending resistance, chemical resistance, and molding dimensional stability.
[0022]
In order to satisfy these requirements, various studies have been made on improving physical properties by alloying a crystalline thermoplastic resin and an amorphous thermoplastic resin, and certain results have been achieved.
[0023]
In these studies, for example, in the field of thermoplastic ester resins, it has been reported that crystalline ester resins and amorphous ester resins can be finely dispersed by promoting transesterification (copolymerization). . However, with conventional technology, if transesterification (copolymerization) is promoted, low molecular weight generation due to depolymerization is accompanied by foaming of the endless belt, or molecular chain scission proceeds to lower the molecular weight. It has not practically been put to practical use for reasons such as a reduction (such as a decrease in tensile elongation at break).
[0024]
Actually, resin products that prevent deterioration of physical properties by suppressing the transesterification reaction have been used as practical products.
[0025]
[Problems to be solved by the invention]
An endless belt made of polycarbonate (hereinafter referred to as PC) has poor bending resistance and has a problem that the belt is cracked and broken while the belt is driven by a roller.
[0026]
Endless belts made of polyalkylene terephthalate (hereinafter referred to as PAT) have reached the level that fully satisfies the market needs as endless belts that can be used until the end of the life of the equipment in recent years, although they have improved bending resistance than PC belts. There wasn't.
[0027]
Endless belts made of fluororesins satisfy bending resistance, but have a low Young's modulus of 1000 to 1400 MPa, tend to stretch when tension is applied, cause color misregistration, and are transferred to paper in a deformed state. There were problems that sometimes occurred.
[0028]
Endless belts made of polyimide (hereinafter referred to as PI) are high-priced belts that satisfy bending resistance but cannot be continuously molded due to thermosetting resins, and are the most expensive among plastics. In addition, the elastic modulus is as high as about 6000 MPa, so the motor load is applied when driving the belt, so the thickness setting must be reduced, and dust once enters between the roller and the belt. If scratches or the like due to friction with the body were introduced, cracks were likely to occur and there was a problem in reliability.
[0029]
Endless belts made of rubber have poor toner releasability, and attempts have been made to solve them by methods such as lamination, but this complicates processes such as vulcanization, surface polishing, and outer layer fluororesin coating. There have been problems such as high price and low elasticity.
[0030]
In an image forming apparatus such as an OA apparatus, electrical characteristics are very important in addition to mechanical characteristics such as price, bending resistance, and Young's modulus, and the electrical resistance value must be uniformly controlled within a certain range. For that purpose, various conductive fillers such as carbon black and metal oxides have been studied. However, if the conductive filler is mixed with the resin, there is a lack of affinity with the resin, and bending resistance is increasing. There was a problem that the mechanical properties of the machine deteriorated.
[0031]
Furthermore, in recent years, printers, copiers, and the like have been sold around the world, so it is necessary to design parts and machines that assume a wide temperature environment of 5 to 40 ° C.
[0032]
However, even in such a wide temperature environment of 5 to 40 ° C., an endless belt that satisfies mechanical properties typified by bending resistance and Young's modulus and electrical properties typified by electrical resistance is still provided. There is no current situation.
[0033]
An object of the present invention is to use an endless belt that is excellent in durability such as bending resistance even under a wide temperature environment of 5 to 40 ° C., can stably form an image normally over a long period of time, and is inexpensive. The present invention provides an image forming apparatus belt and an image forming apparatus.
[0034]
[Means for Solving the Problems]
  Crystalline resin having at least one of a hydroxyl group, a carboxylic acid group and an ester bond, and an amorphous resin having at least one of a hydroxyl group, a carboxylic acid group and an ester bond,Polymerization catalystAnd chelatorsAre heated and mixed, molded, and the mass of metal in the polymerization catalyst is 10 to 500 ppm relative to the total resin,The amount of the chelator is 0.1 to 5 parts by weight with respect to 100 parts by weight of the resin,The crystalline resin is PAT (polyalkylene terephthalate), and the amorphous resin is selected from PC (polycarbonate), PAr (polyarylate), and PMMA (polymethyl methacrylate), and by DSC (differential scanning calorimetry). The difference between the peak temperature indicating the melting peak due to the first temperature increase and the peak temperature indicating the melting peak due to the second temperature increase after cooling is 30 ° C. or less, and the bending resistance according to JIS P-8115 in the belt circumferential direction The tensile modulus at 40 ° C. is 60% or more of the tensile modulus at 5 ° C., and the tensile modulus at 60 ° C. is 20% or more of the tensile modulus at 5 ° C. And the surface electrical resistivity is 1 × 10¹~ 1x10¹⁶Ω or volume electrical resistivity is 1 × 10¹~ 1x10¹⁶Ω · cm, and in one endless belt, the maximum value of the resistivity is 100 times or less the minimum value, and the resin constituting the endless belt has a sea-island structure It is.
[0037]
As a result of intensive studies to achieve the above object, the present inventors have determined the temperature dependence of the structure and elastic modulus of the alloy as characteristics desired for an endless belt that has long-term durability and does not cause image displacement. Focusing on the folding resistance.
[0038]
In other words, a high elastic modulus belt generally has a small tensile elongation at break and a load during driving of the belt increases, so that the thickness cannot be increased. Therefore, it is estimated that cracks may progress if a slight scratch enters from the outside, the inner surface, or the end of the belt, and the relationship between elastic modulus, thickness, tensile elongation at break, and bending resistance is investigated. However, the present plastic material has a high elastic modulus, a large tensile elongation at break, no material with excellent bending resistance, and it has been found that a new material must be developed.
[0039]
In addition, many functional electrical parts such as plastics used in image forming apparatuses are usually formed from thermoplastic resin, resulting in a decrease in mechanical properties due to temperature. Among these mechanical properties, there is at least a certain specific about the tensile elastic modulus. It was noticed that the image showing the elastic modulus characteristics under the above temperature conditions can form a normal image at a wide range of environmental temperatures.
[0040]
Therefore, we focused on the morphology of recent engineering plastic (engineering plastic) alloys. In other words, an endless belt with a structure in which crystalline engineering plastics and amorphous engineering plastics are copolymerized by alloying (random, graft, or block copolymerization) should be the cheapest endless belt with excellent bending resistance. As a result of diligent investigation based on knowledge, it was pelletized under certain compound conditions in alloying of crystalline polyester resin and other resins (for example, amorphous polyester resin), and made under certain molding conditions. It has been found that it can be an endless belt that is excellent in bending resistance, maintains high tensile elastic modulus, and is low in cost and difficult to crack.
[0041]
In general, ordinary plastic alloys can be broadly classified into two types, compatible alloys and incompatible alloys.
[0042]
It is known that an incompatible alloy does not completely mix even when two types of thermoplastic resins are melt-mixed and has a sea-island structure. If there is a large difference in volume fraction between the two thermoplastic resins, the larger the volume fraction is, the smaller the volume fraction is at sea, and the smaller the volume fraction, the easier it is to form an island structure. Has an effect on the sea-island structure, and it is said that the smaller the melt viscosity is, the easier it is to become the sea, and the larger is the island.
[0043]
In this incompatible alloy, there is always a boundary between sea-islands between different materials, so it is presumed that the interface is most likely to break and causes a decrease in bending resistance. Therefore, the present inventors have inferred that an endless belt excellent in bending resistance should be completed by reinforcing the interface by graft polymerization, block polymerization or the like.
[0044]
On the other hand, in the compatible alloy, there is no interface between different materials, and the sea-island structure is usually not recognized. Such a compatible material is said to have mechanical properties such as flex resistance that are in accordance with the blending ratio of both materials. Therefore, since it is unlikely that a dramatic improvement in flex resistance will be expected, the present inventors should be able to significantly improve the mechanical properties represented by flex resistance if they are compatible and copolymerized. I guessed there was.
[0045]
In other words, the inventors have intensively studied to demonstrate the idea that an endless belt with the most excellent mechanical properties should be created by forming a copolymerized state with both incompatible and compatible alloyed materials.
[0046]
Therefore, attention was first focused on low-cost polyester resins.
[0047]
In general, it is known that an alloy of a polyester-based resin exchanges with each other by performing molecular cleavage called a transesterification reaction. In addition, this transesterification reaction is generally accompanied by molecular chain breakage, and as a result, it is said that it causes foaming or brittleness and causes mechanical properties to deteriorate.
[0048]
However, the present inventors consider that this transesterification reaction should be accompanied by a copolymerization reaction, and if a specific condition is set, a decrease in mechanical properties due to molecular chain breakage is suppressed. However, as a result of examining materials, compound conditions, and molding conditions based on the assumption that the transesterification reaction could be further transferred to a copolymerization reaction, using engineering plastics of the same composition, (1) It can be seen that a structure having a sea-island structure, (2) a structure having a sea-island structure but having a copolymerized interface, and (3) a structure having no sea-island structure can be seen. It was found that the mechanical properties represented by (1) were higher than (1) by (2), and (2) by (3).
[0049]
Furthermore, in the structure (2) or (3), it was found that there was almost no decrease in mechanical strength even when a third component such as a conductive filler was added.
[0050]
Furthermore, even when a conductive filler is added and controlled to a specific electric resistance, the conductive filler is fixed to the copolymerized resin component in the structure (2) or (3) above. Therefore, it was found that it is electrically stable and changes little over time.
[0051]
Furthermore, it has been found that even such a structure can be arbitrarily set by electric resistance control using a conventional technique by controlling the concentration of the conductive filler or changing the conditions of the molding process.
[0052]
Also, by using these techniques, an endless belt capable of controlling the tensile modulus, thickness, and tensile elongation at break was made possible, and the relationship between these physical properties, image shift of the endless belt, and durability could be verified.
[0053]
As a result, it has been found that only a belt having a specific tensile elastic modulus temperature characteristic, electrical resistance, and bending resistance can be an endless belt that does not cause image misalignment and cracking for a long time, and has arrived at the endless belt of the present invention. .
[0054]
In addition, the inventor heat-kneaded a crystalline resin, an amorphous resin, and a polymerization catalyst, and shows a melting peak due to the first temperature rise by DSC (differential scanning calorimetry) and a second time after cooling. The endless belt whose difference from the peak temperature indicating the melting peak due to the temperature rise is 30 ° C. or less has no image displacement over a longer time than the endless belt obtained by the conventional methods for suppressing the reaction such as the transesterification reaction, The inventors have found that no cracks occur and have arrived at the endless belt of the present invention.
[0055]
That is, among the structures (1), (2) and (3) above, the structure (sea island structure) in which the crystal component and the amorphous component of (1) or (2) are left, respectively, has a wide temperature range. It has been found that the belt is not easily stretched under the environment, and that the belt is stretched due to the high temperature environment or over a period of several days to several years, and deformation due to creep is difficult to occur.
[0056]
This phenomenon was analyzed by the thermal characteristics of the thermopolymer by differential scanning calorimetry (DSC). (In this thermal characteristic, by applying heat, we can capture the movement from macroscopic segmental motion to macroscopic motion of macromolecules, looking at micro Brownian motion at the glass transition point and folding motion at the melting point. ).
[0057]
In this DSC measurement, the temperature was first raised at a constant rate, then cooled at a constant rate, and further heated at a constant rate, and the endothermic peak point at the time of melting was measured. As a result, if the temperature difference between the melting peak point in the first heating process and the melting peak point in the second heating process is greater than 30 ° C., the amount of resin that has probably not been reacted yet remains. Therefore, it is recognized that the tensile elastic modulus is greatly reduced at high temperatures, and the belt may be stretched or deformed due to creep in a high temperature environment or over several days to several years. It was. On the contrary, when the temperature difference is 30 ° C. or less, it is recognized that the decrease in tensile elastic modulus at high temperature is small and the creep is extremely small, and the endless belt of the present invention has been conceived.
[0058]
The endless belt of the present invention heats a crystalline resin having at least one of a hydroxyl group, a carboxylic acid group and an ester bond, an amorphous resin having at least one of a hydroxyl group, a carboxylic acid group and an ester bond, and a polymerization catalyst. A resin having a melting peak temperature difference of 30 ° C. or less, a crystalline resin having at least one of a hydroxyl group, a carboxylic acid group and an ester bond, and at least one of a hydroxyl group, a carboxylic acid group and an ester bond An amorphous resin and a polymerization catalyst may be mixed by heating and may be made of a resin obtained by mixing a resin having the above melting peak temperature difference exceeding 30 ° C.
[0059]
The belt for an image forming apparatus of the present invention is an intermediate transfer belt, a conveyance transfer belt, or a photoreceptor belt made of this endless belt.
[0060]
The image forming apparatus of the present invention comprises this image forming apparatus belt.
[0061]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
(1) The endless belt of the present invention is used in an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, or a facsimile machine as an intermediate transfer belt, a transfer transfer belt, a photosensitive belt, or the like.
[0062]
In order to obtain an endless belt, a method in which a crystalline resin, an amorphous resin, and a polymerization catalyst are mixed by, for example, a twin-screw kneading extruder, pelletized, and then formed into an endless belt is particularly preferably used.
[0063]
The molding method is not particularly limited, and can be obtained by employing a known method such as a continuous melt extrusion molding method, an injection molding method, a blow molding method, or an inflation molding method. This is a continuous melt extrusion method. In particular, the internal cooling mandrel method or vacuum sizing method of the downward extrusion method capable of controlling the inner diameter of the extruded tube with high accuracy is preferable, and the internal cooling mandrel method is most preferable.
[0064]
In addition, an endless belt with better physical properties can be obtained by optimizing the temperature and residence time during molding, so it is preferable to adjust the conditions according to each formulation.
[0065]
The endless belt of the present invention may be used as it is, or may be wound around a drum or a roll.
[0066]
Further, for the purpose of preventing meandering or reinforcing the end face, a heat resistant tape is attached to the inside and / or the vicinity of the outer end of the endless belt of a predetermined dimension, or a tape such as urethane rubber or silicone rubber is attached to the inner end of the belt. You may affix on the part vicinity.
[0067]
(2) Physical properties of endless belt
According to the present invention, an endless belt having the following physical properties is provided.
[0068]
(Number of folding times)
When the endless belt used in the present invention is used as an intermediate transfer belt in an image forming apparatus, for example, an endless belt having good bending resistance is preferred because cracks occur and images cannot be obtained if the bending resistance is poor.
[0069]
The degree of bending resistance can be quantitatively evaluated by following the method for measuring the folding endurance of JIS P-8115, and it is judged that an endless belt with a higher folding endurance is less susceptible to cracking and has superior bending resistance. be able to.
[0070]
As a specific numerical value, if it exceeds 5000 times, it can be used with an excellent function as an endless belt for the life of the apparatus, but practically it is preferably 8000 times or more and preferably 10,000 times or more. It is more preferable if it is 15000 times or more, since cracks are particularly difficult to occur and sufficient crack resistance can be obtained without performing secondary processing such as a crack prevention reinforcing tape.
[0071]
(Tensile modulus)
If the tensile elastic modulus of the endless belt is low, for example, when it is used in an image forming apparatus as an intermediate transfer belt, a slight elongation may occur due to the tension, which may cause problems such as color misregistration. Specifically, it is necessary to be 1500 MPa or more, preferably 2000 MPa or more, particularly preferably 3000 MPa, and 3500 MPa or more is particularly preferable because problems such as color misregistration can be significantly suppressed.
[0072]
In general, a soft plastic has a high folding resistance but tends to have a low tensile elastic modulus. Conversely, a hard plastic can obtain a high tensile elastic modulus but tends to become brittle and often has only a low folding resistance. In this invention, it can be said that it is useful in the meaning which can obtain a high frequency | count of folding-proof, maintaining the characteristic of the inherent high tensile elasticity modulus which PBT and PC have.
[0073]
If this tensile elastic modulus is excessively high, the motor load becomes excessive when the belt is driven, and cracks are liable to occur. Therefore, it is necessary that it be 5000 MPa or less, and 4500 MPa or less is preferable.
[0074]
(Temperature elastic modulus temperature characteristics)
As the temperature characteristics of the tensile modulus, the tensile modulus at 40 ° C. is 60% or more of the tensile modulus at 5 ° C., and the tensile modulus at 60 ° C. is 20% with respect to the tensile modulus at 5 ° C. That is important. In other words, the change in tensile modulus is small between 5 ° C. and 40 ° C., and it is preferably moderately reduced between 40 ° C. and 60 ° C.
[0075]
If the tensile elastic modulus at 40 ° C is less than 60% of the tensile elastic modulus at 5 ° C, the belt stretches during use in printers or copiers in the summer or at high temperatures, causing images to shift or creep deformation. It becomes easy to do. Preferably, the tensile elastic modulus at 40 ° C. is 70% or more with respect to the tensile elastic modulus at 5 ° C., more preferably 80% or more.
[0076]
Further, it is important that the tensile modulus at 60 ° C. is 20% or more with respect to the tensile modulus at 5 ° C. If the tensile elastic modulus at 60 ° C. is less than 20% of the tensile elastic modulus at 5 ° C., belt creep and dimensional changes are likely to occur over time from several days to several years, which is not preferable.
[0077]
Particularly preferably, the tensile elastic modulus at 60 ° C. is 40% or more, more preferably 60% or more with respect to the tensile elastic modulus at 5 ° C.
[0078]
(Melting peak characteristics by DSC)
The difference between the peak temperature showing the melting peak due to the first temperature increase by DSC and the peak temperature showing the melting peak due to the second temperature increase after cooling is preferably 30 ° C. or less.
[0079]
The above peak is an indicator of whether the molded part is in a state that changes over time (whether there is an unreacted part). If this peak difference is large, the endless belt has dimensions and mechanical properties over time. It is not preferable because the change over time such as is considered to be large.
[0080]
A preferable peak temperature difference is 20 ° C. or less, and 10 ° C. or less is particularly preferable.
[0081]
Even if mechanical properties such as durability and tensile elastic modulus are good at room temperature, it cannot be used as a part if it changes over time. It is.
[0082]
  (Alloy structure)
  Of the present inventionEndless beltIs an alloy structure with a sea-island structure.TheIn particular, in the case of a structure in which a crystalline component and an amorphous component are alloyed or a configuration in which fillers are added, the structure of the polymer material heated and melted may change during the cooling process. For example, in the presence of a filler or the like, the material that should be crystallized may not be crystallized and may remain in an amorphous state in the presence of a filler. Care must be taken because it may cause shrinkage to an extremely small size, or the mechanical strength may extremely decrease.
[0083]
In order to prevent such a state, it is necessary to adopt a crystallized structure as a molded member in the material of the crystal component among the components to be alloyed.
[0084]
Such a sea-island structure is observed in a state where an ultrathin section stained with ruthenium tetroxide for 2 minutes or more is observed with a transmission electron micrograph.
[0085]
In the molded member of the present invention, it is preferable that at least a portion having a sea-island structure is confirmed and has a specific elastic modulus and bending strength.
[0086]
(Surface resistivity)
The endless belt used in the present invention can obtain conductivity by blending a conductive filler or a substance exhibiting conductivity as required.
[0087]
The resistance region varies depending on the purpose, but the surface resistivity is 1 × 10¹~ 1x10¹⁶Ω or volume resistivity 1 × 10¹~ 1x10¹⁶It is selected from the range of Ω · cm.
[0088]
The preferred range varies depending on the application, but for example, when used as a photoreceptor belt, the surface resistivity is 1 × 10 so that the charge on the outer surface can escape to the inner surface as necessary.¹~ 1x10⁹Ω or volume resistivity 1 × 10¹~ 1x10⁹A resistivity as low as Ω · cm is preferable. When used as an intermediate transfer belt, a surface resistivity of 1 × 10 can be easily charged and transferred.⁶~ 1x10¹³Ω or volume resistivity 1 × 10⁶~ 1x10¹³Ω · cm is preferable, and when used as a transfer belt, it is easily charged and is not easily damaged even at high voltages.¹⁰~ 1x10¹⁶Ω or volume resistivity 1 × 10¹⁰~ 1x10¹⁶A region as high as Ω · cm is preferable.
[0089]
Further, it is preferable that the distribution of the surface resistivity in one endless belt is narrow, and in each preferable surface resistivity region, the difference between the maximum value and the minimum value in one is within two digits (the maximum value is It is preferably 100 times the minimum value).
[0090]
The surface resistivity and volume resistivity of the film can be easily measured by, for example, Hiresta, Loresta manufactured by Dia Instruments Co., Ltd. or R8340A manufactured by Advantest Co., Ltd.
[0091]
(Endless belt thickness)
If the thickness of the endless belt is excessively large, if the curvature with the roller is large, the deformation difference between the outer side and the inner side of the belt is large, and the endless belt is easily cracked. In addition, the toner transferred to the outer side is deformed and scattered to deform the image. On the other hand, if the thickness of the endless belt is excessively small, cracks easily occur due to a slight amount of dust that has entered between the roller and the belt, or damage due to contact with the photosensitive member, and the belt is likely to break. Accordingly, the thickness of the endless belt needs to be 70 to 300 μm, and is particularly preferably 100 to 200 μm.
[0092]
(3) Endless belt material
In the present invention, it is basically sufficient that the tensile elastic modulus, tensile elongation at break, bending resistance, and thickness satisfy a certain range, and there is no limitation on the type of material, and a known thermoplastic or thermosetting resin is the main component. It can be. However, the tensile elastic modulus of the material is preferably 1500 MPa or more, and even when alloyed, the tensile elastic modulus of each base material is preferably 1500 MPa or more.
[0093]
In particular, preferred materials for obtaining the mechanical properties of the present invention are a crystalline resin having at least one of a hydroxyl group, a carboxylic acid group and an ester bond, and an amorphous material having at least one of a hydroxyl group, a carboxylic acid group and an ester bond. Resin and polymerization catalyst are included.
[0094]
  (Crystalline resin)
  The crystalline resin used for the endless belt of the present invention has at least one of a hydroxyl group, a carboxylic acid group and an ester bond, and has a crystallinity of 10% or more and 100% or less.PAT (polyalkylene terephthalate)UsingThe
[0095]
  PATAmong them, PBT (polybutylene terephthalate), PET (polyethylene terephthalate), and PEN (polyethylene naphthalate) are more preferable. PBT has a high crystal acceleration, so there is little change in crystallinity due to molding conditions, and it is generally about 30%. It is particularly preferable because it is stable in degree.
[0096]
Moreover, the crystalline resin used for this invention can also introduce | transduce a copolymerization component in the range which does not impair the effect of this invention remarkably. Specific examples include those in which an ester bond is the main chain and an ester bond such as polymethylene glycol is introduced.
[0097]
There is no particular limitation on the molecular weight of the crystalline resin used in the endless belt of the present invention. For example, a resin having a general molecular weight such as a weight average molecular weight of 10,000 to 100,000 can be used. When there is a high demand, a high molecular weight is preferable. Specifically, it is preferably 20,000 or more, more preferably 25,000 or more, and particularly preferably 30,000 or more.
[0098]
  (Amorphous resin)
  The amorphous resin used in the endless belt of the present invention has at least one of a hydroxyl group, a carboxylic acid group and an ester bond, and has a crystallinity of 0% or more and less than 10%.PC (polycarbonate), PAr (polyarylate), and PMMA (polymethyl methacrylate) are used. Among these, PC can be used particularly preferably.
[0100]
The amorphous resin used for the endless belt of the present invention can introduce a copolymer component within a range that does not significantly impair the effects of the present invention. Specific examples include those in which an ester bond is the main chain and an ester bond such as polymethylene glycol is introduced.
[0101]
The molecular weight of the amorphous resin used in the endless belt of the present invention is not particularly limited, and for example, a resin having a general molecular weight such as a weight average molecular weight of 10,000 to 100,000 can be used. When there is a demand for high physical properties, those having a high molecular weight are preferred. Specifically, it is preferably 20,000 or more, more preferably 25,000 or more, and particularly preferably 30,000 or more.
[0102]
(Weight ratio of crystalline resin to amorphous resin)
There is no restriction | limiting in particular in the weight ratio of the crystalline resin used for the endless belt of this invention, and an amorphous resin. However, in general, a crystalline resin is excellent in chemical resistance and flex resistance, and an amorphous resin is excellent in molding dimensional stability, so an arbitrary ratio can be set according to the purpose of use. 1/99 to 99/1 is preferable, 40/60 to 97/3 is more preferable, 60/40 to 95/5 is further preferable, and 70/30 to 90/10 is preferable. Is particularly preferred.
[0103]
The reason why the ratio of the crystalline resin is selected as a particularly preferable ratio is that the amorphous resin can be expected to sufficiently improve the molding dimensional stability with a small amount of blending, and the amorphous resin is slightly blended excessively. This is due to the fact that the effects of chemical resistance such as solvents during painting may be noticeable.
[0104]
(Difference in viscosity between crystalline resin and amorphous resin)
If the difference in viscosity between the two resins is too large, good dispersion may not be obtained even if the production conditions are adjusted, and uniform dispersion may not be achieved.
[0105]
Specifically, MFR measurement is performed on both resins under the same conditions, and the value is preferably within a range of about 1/20 to 20/1, and more preferably within a range of 1/10 to 10/1.
[0106]
The measurement method is based on JIS K-7210, and it is preferable to select a measurement temperature condition close to the processing temperature of the resin.
[0107]
For example, when PBT and PC are selected, it is preferable to set a processing temperature of 260 ° C. as the measurement temperature and compare the viscosity difference between the two resins. Moreover, it can measure suitably by selecting 2.16 kg, for example as a load.
[0108]
(Polymerization catalyst)
The polymerization catalyst is not particularly limited as long as it has an ability to polymerize a crystalline resin and an amorphous resin.
[0109]
Of the polymerization catalysts, Ti-based polymerization catalysts are preferred, and alkyl titanates can be suitably used.
[0110]
Among the alkyl titanates, tetrabutyl titanate or tetrakis (2-ethylhexyl) orthotitanate is preferable, and these are easily available as TYZOR TOT (manufactured by DuPont) or TYZOR TBT (manufactured by DuPont).
[0111]
Further, the Ti-based polymerization catalyst is preferably combined with an alkali metal, alkaline earth metal-containing compound or zinc-containing compound because it works more effectively, and it is particularly preferable to have an Mg-containing compound as a polymerization catalyst.
[0112]
Although there is no restriction | limiting in particular as a compound containing Mg, Organic acid Mg salt is especially preferable, and Mg acetate is especially preferable.
[0113]
  If the content of the polymerization catalyst is too small, it may not work effectively, so it is preferable that the content is high to some extent.10ppm or lessAbove, preferably20ppm or moreRu. On the other hand, ester resins are known to cause depolymerization in the presence of a large amount of heavy metals.500ppm or lessTo.
[0114]
(Chelator)
In the present invention, if the activity of the polymerization catalyst is too high, the depolymerization of the resin is promoted and mechanical properties are reduced due to a decrease in molecular weight, and foaming associated with the generation of a low molecular weight product may cause problems.
[0115]
In the present invention, if there is a chelator having the ability to chelate the metal in the polymerization catalyst, depolymerization can be suppressed.
[0116]
There is no restriction | limiting in particular as a kind of chelator, A well-known chelator can be used.
[0117]
Examples include phosphites, phosphates, phosphates, and hydrazines, such as Irgafos 168 (manufactured by Ciba Geigy Japan), PEP36 (manufactured by Asahi Denka Kogyo Co., Ltd.). PEPQ (manufactured by Clariant Japan), IRGANOX MD1024 (manufactured by Ciba-Geigy Japan), CDA-6 (manufactured by Asahi Denka Kogyo Co., Ltd.), and hydrazines are easily obtained from the market. be able to.
[0118]
  The amount of these chelators added is, 0. 1 part by weight or moreWhenYouThe
[0119]
  If the amount of the chelator is too large, the polymerization catalyst loses its activity and an endless belt with good physical properties may not be obtained. Therefore, it is preferable not to add too much, with respect to 100 parts by weight of the resin.5Up to parts by weightThe
[0120]
In general, it is preferable to use a small amount of 0.1 parts by weight or less as a usage of a chelator, but when using a chelator in the present invention, an example of a particularly preferable usage is the addition of a polymerization catalyst. The amount is added as much as 50 to 500 ppm, and the chelator is also used in an amount of 0.5 to 5 parts by weight, preferably 0.7 to 2 parts by weight and higher than common sense. When the residence time and the like are optimized, it is possible to suppress the depolymerization while promoting the chemical bond generation and the molecular weight increase between the crystalline resin and the amorphous resin, and it is possible to obtain an endless belt with excellent physical properties that has never been obtained.
[0121]
(Conductive substance)
In the present invention, when it is necessary to adjust the electric resistance value, a conductive substance may be blended. In particular, in an endless belt or the like used in an image forming apparatus, it is necessary to adjust the surface resistance value or the volume resistance value according to the use in order to electrically attract and transfer toner, paper, and the like.
[0122]
The conductive material to be blended is not particularly limited as long as it satisfies the performance required for the application, and various materials can be used. Specifically, as the conductive filler, carbon black or carbon fiber can be used. Carbon-based fillers such as graphite, metal-based conductive fillers, metal oxide-based conductive fillers, and the like are used. In addition to the conductive fillers, ion conductive substances such as quaternary ammonium salts are exemplified.
[0123]
A particularly preferable conductive material is carbon black having excellent dispersibility.
[0124]
As the type of carbon black, acetylene black, furnace black, channel black and the like can be suitably used, and among these, acetylene black which has few functional groups as impurities and hardly causes poor appearance due to carbon aggregation can be particularly suitably used. Furthermore, the primary particle diameter is 10 to 100 nm, and the specific surface area is 10 to 200 m.²/ G, those having a pH value of 3 to 11 are more preferred.
[0125]
Moreover, the carbon black to be used may be one type or two types. Furthermore, there is no problem even if carbon black subjected to a known post-treatment process such as carbon black coated with resin, carbon black subjected to graphitization, or carbon black subjected to acid treatment is used as the carbon black.
[0126]
Further, for the purpose of improving the dispersibility of the conductive filler, a conductive filler such as carbon black treated with a coupling agent such as silane, aluminate, titanate, or zirconate may be used.
[0127]
The blending amount of such carbon black is preferably 3 to 30% by weight in terms of the content in the belt, and particularly preferably within the above range, 10 to 25% by weight. When the above range is exceeded, the appearance of the product is deteriorated, and the material strength is lowered, which is not preferable.
[0128]
(Additional ingredients; optional ingredients)
In the endless belt of the present invention, arbitrary blending components can be blended according to various purposes.
[0129]
Specifically, irgafos 168, irganox 1010, antioxidants such as phosphorus antioxidants, heat stabilizers, various plasticizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, antifogging agents, anti Various additives such as a blocking agent, a slip agent, a crosslinking agent, a crosslinking aid, a colorant, a flame retardant, and a dispersant can be added.
[0130]
Furthermore, compounding materials such as various thermoplastic resins, various elastomers, thermosetting resins, and fillers can be blended as the second and third components within a range that does not significantly impair the effects of the present invention.
[0131]
Thermoplastic resins include polypropylene, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, rubber or latex components such as ethylene / propylene copolymer rubber, styrene Butadiene rubber, styrene / butadiene / styrene styrene block copolymer or its hydrogenated derivatives, polybutadiene, polyisobutylene, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, polyimide, liquid crystalline polyester, polysulfone, polyphenylene sulfide, poly Bisamidotriazole, polyetherimide, polyetheretherketone, acrylic, polyfluorinated vinylidene, polyfluorinated vinyl, polychlorotrifluoroethylene, ethylene Tetrafluoroethylene copolymer, hexafluoropropylene tetrafluoroethylene copolymer, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, alkyl acrylate ester copolymer, polyester ester copolymer, polyether ester copolymer, poly What consists of 1 type, such as an etheramide copolymer and a polyurethane copolymer, or these mixtures can be used. As a thermosetting resin, what consists of 1 type, such as an epoxy resin, a melamine resin, a phenol resin, unsaturated polyester resin, or these mixtures, for example can be used. Examples of various fillers include calcium carbonate (heavy and light), talc, mica, silica, alumina, aluminum hydroxide, zeolite, wollastonite, diatomaceous earth, glass fiber, glass beads, bentonite, asbestos, and hollow. Glass ball, graphite, molybdenum disulfide, titanium oxide, carbon fiber, aluminum fiber, styrene steel fiber, brass fiber, aluminum powder, wood powder, rice husk, metal powder, conductive metal oxide, organometallic compound, organometallic salt In addition to fillers such as antioxidants as additives (phenolic, sulfur, phosphate ester, etc.), lubricants, various organic and inorganic pigments, UV inhibitors, antistatic agents, dispersants, neutralizing agents, Examples thereof include a foaming agent, a plasticizer, a copper damage inhibitor, a flame retardant, a crosslinking agent, and a flow improver.
[0132]
(Heat kneading)
In the present invention, a crystalline resin, an amorphous resin and a polymerization catalyst are heated and kneaded to form a resin composition, and then an endless belt is formed. Alternatively, a crystalline resin, an amorphous resin and a polymerization catalyst are heated and kneaded. You can also get an endless belt.
[0133]
In this case, the conditions should be adjusted so that a bond between the crystalline resin and the amorphous resin can be generated either by heat kneading at the stage of obtaining the resin composition or by heat kneading at the stage of molding the resin composition into an endless belt. It ’s fine. In any case, the heating temperature cannot be sufficiently dispersed unless it is in a molten state. Therefore, it is preferable that the heating temperature is higher to some extent. Specifically, the melting point of the crystalline resin should be used as a guideline, and the heating temperature should be higher than the melting point of the crystalline resin. Is preferable, and it is further more preferable that it is melting | fusing point +10 degreeC or more. Further, if the heating temperature is too high, thermal decomposition may be caused and physical properties may be deteriorated. Therefore, it is preferable that the heating temperature is too low. Specifically, the melting point of the crystalline resin is used as a guideline, and the melting point of the crystalline resin + 80 ° C. The following is preferable, and it is more preferable that it is melting | fusing point +60 degrees C or less.
[0134]
Moreover, since the endless belt having better physical properties may be obtained by drying the raw material before heating and kneading, it is preferable to perform drying.
[0135]
In some cases, after heat-kneading to obtain a resin composition, heat treatment is performed at a temperature lower than the melting point to form an ester bond, and then an endless belt can be formed.
[0136]
In the present invention, it is considered that the polymerization catalyst can promote the reaction of the crystalline resin and the amorphous resin to obtain an endless belt having excellent physical properties. The reaction to be promoted requires temperature, pressure and time during heat kneading, so it is necessary to set the heat kneading conditions while grasping the dispersion form of the obtained endless belt. Care must be taken because a low molecular weight product is generated as a by-product during this reaction, and if it cannot be removed from the system, this will cause a decrease in molecular weight and foaming of the molded product.
[0137]
Although it is a means for heat kneading, there is no particular limitation on this, and a known technique can be used. For example, if a crystalline resin, an amorphous resin, and a polymerization catalyst are first heat-kneaded to obtain a resin composition, a single-screw extruder, a twin-screw kneading extruder, a Banbury mixer, a roll, a Brabender, a plastograph, a kneader Etc. can be used. Moreover, even when obtaining an endless belt from the resin composition thus obtained, a known technique can be used. For example, an injection molding machine or an extrusion molding machine.
[0138]
(Heat treatment)
By heat-treating the obtained endless belt, it becomes possible to obtain a forming member with improved physical properties. In particular, the number of folding times and the tensile modulus are improved.
[0139]
Although the heat treatment conditions depend on the raw material resin used, the temperature is usually 60 to 200 ° C., preferably 70 to 120 ° C. for 5 to 60 minutes, preferably about 10 to 30 minutes.
[0140]
(Chemical bond between molecular chain of crystalline resin and molecular chain of amorphous resin)
In the endless belt of the present invention, by forming a chemical bond between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin, the affinity between the two resins is increased, and the fine dispersion of the form is promoted. An endless belt having both high bending resistance of the resin, dimensional stability of the amorphous resin, and (depending on conditions) can be obtained.
[0141]
The abundance ratio of the chemical bond is not particularly limited, but is basically preferably larger. Specifically, the crystallinity per mol of chemical bond between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin. The total mass of the resin and the amorphous resin is preferably 1,000,000 g or less, more preferably 300,000 g or less, and particularly preferably 100,000 g or less.
[0142]
Although there is no restriction | limiting in particular in the measuring method of the quantity of a chemical bond, For example, it can measure by NMR.
[0143]
A measurement example in the case of using PBT as the crystalline resin and PC as the amorphous resin is shown below.
[0144]

By this measurement, the charts shown in FIGS. FIG. 2 is an enlarged view of the portion II in FIG.
[0145]
The chemical shift of benzene ring hydrogen of terephthalic acid (TPA) differs between when carboxylic acid is bonded to butanediol and bisphenol A (BPA).
[0146]
In general, four TPA benzene ring hydrogens (d) in the PBT molecule are equivalent as shown in Chemical formula 1, and show a singlet peak at a chemical shift of 8.07.
[0147]
[Chemical 1]

[0148]
On the other hand, the benzene ring hydrogen in TPA of PBT bonded to BPA of PC as shown in chemical formula 2 changes the chemical shift, hydrogen (b) has a doublet at 8.25, and (c) has a doublet peak at 8.13. Show.
[0149]
[Chemical formula 2]

[0150]
The area ratio of (d): {(b) + (c)} can determine the ratio of TPA in the PBT molecule to TPA bound to PC.
[0151]
In this example, the area ratio is (d): {(b) + (c)} = 100: {0.4654 + 0.5635} ≈99.01: 0.99, so 0.99 mol per 100 mol of PBT structural unit. It can be seen that it has a TPA (derived from PBT) -BPA (derived from PC) bond. In addition, since it can be easily estimated that the same amount of butanediol (derived from PBT) -carbon (PC) bond is present in the resin composition, 1.98 mol of PBT-PC bonds per 100 mol of PBT structural units in total. Is understood to exist.
[0152]
As shown in Chemical formula 3, since the formula amount of the PBT structural unit (butanediol + TPA) is 220, there is 1.98 mol of PBT-PC bond per g of PBT22000 (220 × 100 mol).
[0153]
The mass of PBT per mol of PBT-PC bond can be calculated as about 11000 (22000 / 1.98).
[0154]
In this example, since the weight ratio of PBT to PC is 7/3, the resin content (PBT mass + PC mass) per 1 mol of PBT-PC bond can be determined to be 16000 g (11000 / 0.7).
[0155]
[Chemical Formula 3]

[0156]
(Molecular weight)
In the present invention, a crystalline resin, an amorphous resin, and a polymerization catalyst are heated and kneaded to form a chemical bond between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin, and as a resin composition Since it is considered that the physical properties of the obtained endless belt can be improved by maintaining or increasing the total molecular weight, it is preferable that the molecular weight is high.
[0157]
Although it is a method for measuring molecular weight, it is difficult to determine the true value of molecular weight when a copolymer is present as in the present invention.
[0158]
Therefore, in the present invention, all resins were measured by GPC under the same conditions, and the value obtained as the PS-converted weight average molecular weight was used as a common representative value.
[0159]
As measurement conditions, 20 mg of a sample was dissolved overnight in 0.5 ml of 1,1,1,3,3,3-hexafluoro-2-propanol and 0.2 ml of chloroform, and further 25 ml of a mobile phase solvent was added. The solution was filtered through a 0.22 μm filter to obtain a SEC measurement solution. It was performed within 12 hours from the addition of the mobile phase to the end of the measurement.
[0160]
SEC measurement conditions
Solvent chloroform / acetic acid: 99.5: 0.5 (vol / vol)
Flow rate 1.0ml / min
Injection volume 0.02ml
2 columns AD806M / S (made by Showa Denko)
Column temperature 30 ° C
Detector UV 254nm
Using 12 samples of monodispersed standard polystyrene (manufactured by Tosoh Corp.) having different molecular weights from 500 (A-500) to 2,890,000 (F-288), a calibration curve was prepared and the molecular weight in terms of polystyrene was calculated.
[0161]
In this method, the PS-converted weight average molecular weight (Mw) of the resin composition obtained after heating and kneading the crystalline resin, the amorphous resin, and the polymerization catalyst.₃Specifically, as the value of X, the blending ratio of the crystalline resin is X parts by weight, and the weight average molecular weight in terms of polystyrene (PS) is Mw.₁, The blending ratio of the amorphous resin is Y parts by weight, and the weight average molecular weight in terms of PS is Mw₂As
[0162]
[Expression 2]

[0163]
It is preferable that
[0164]
[Equation 3]

[0165]
More preferably,
[0166]
[Expression 4]

[0167]
It is particularly preferable because sufficiently high physical properties can be obtained.
[0168]
In the present invention, Mw₃Mw by heating and mixing₁And Mw₂It is important that it is higher than the arithmetic average value of₁And Mw₂Even if the resin is used, the final Mw₃It is considered that good physical properties cannot be expected even if the₃The absolute value of is not particularly limited, but it is still preferably high from a comprehensive point of view. Specifically, the weight average molecular weight in terms of PS is preferably 130,000 or more, more preferably 140,000 or more, and 150, 000 or more is particularly preferable.
[0169]
As an example of the correlation between the true value of the weight average molecular weight and the weight average molecular weight in terms of PS, when a PBT having a weight average molecular weight of 40,000 is measured by the above method, a value of PS equivalent weight average molecular weight of 122,000 is obtained. It is known that when a PC having an average molecular weight of 28,000 is measured by the above method, a PS-converted weight average molecular weight of 64,000 is obtained.
[0170]
(Distributed form)
Generally, it is known that even if two types of thermoplastic resins are melt-mixed, they are not completely mixed and have a fluid structure. If there is a large difference in volume fraction between the two thermoplastic resins, the larger the volume fraction is, the smaller the volume fraction is, and the smaller the volume fraction, the easier it is to form an island structure. It has been said that it has an effect on the sea-island structure, and the smaller the melt viscosity is, the easier it is to become the sea, and the larger is the island.
[0171]
There is no particular limitation on the method for confirming the dispersion state.₄After staining with, a known method such as preparing an ultrathin section and observing with TEM can be used.
[0172]
(Use of endless belt)
Although there is no restriction | limiting in particular in the use of this endless belt, It can use suitably for the OA equipment field | area with severe strict physical properties, such as a dimensional accuracy, bending resistance, and tensile breaking elongation, especially a functional member. When this endless belt is formed in a seamless belt shape, there are few problems such as cracking and elongation, which is preferable.
[0173]
This endless belt can be suitably used, for example, as an electrophotographic intermediate transfer belt, a conveyance transfer belt, or a photoreceptor belt.
[0174]
A reinforcing tape may be attached to the endless belt along the side edge as necessary. As the reinforcing tape, a biaxially stretched polyester tape is preferable in terms of cost and strength, and the tape width is preferably 4 mm or more and 20 mm or less because the apparatus layout is compact. The thickness of the reinforcing tape is preferably 20 μm or more and 200 μm or less from the viewpoint of being able to drive the endless belt with low tension and preventing the occurrence of cracking.
[0175]
【Example】
The present invention will be described more specifically with reference to examples and comparative examples.
[0176]
(material)
The following materials were used, and the blending ratios were as shown in Table 1 or Table 2.

(Heat kneading)
Each raw material was pelletized using a twin-screw kneading extruder (PMG32 manufactured by IKG Co., Ltd.).
[0177]
(Endless belt molding method)
This material pellet was dried and extruded in a molten tube state below the annular die by a 40 mmφ extruder with a 6-spiral annular die having a diameter of 180 mm and a lip width of 1 mm, and the extruded molten tube was placed on the same axis as the annular die. While contacting and cooling the outer surface of a cooling mandrel with an outer diameter of 170 mm mounted via a support rod, the seamless belt is then provided by a core installed in the seamless belt and a roll installed outside. Was cut in a length of 340 mm while being held in a cylindrical shape, and the extrusion amount and the take-up speed were adjusted so that the predetermined thickness and residence time described in Table 1 were obtained, to obtain a resin seamless belt having a diameter of 169 mm. .
[0178]
Conditions such as molding temperature and residence time were as shown in Table 1.
[0179]
(Evaluation)
The evaluation was carried out by cutting the endless belt to the required size as required.
・ Surface resistivity Ω
The surface resistivity can be properly measured depending on the measuring instrument.
[0180]
Surface resistivity is 1-1 × 10⁶As a sample to be Ω, Diales Instruments Co., Ltd. Loresta was used, and the belt circumferential direction was measured at a pitch of 20 mm.
[0181]
Surface resistivity is 10⁶~ 1x10¹³As a sample to be Ω, Hiresta (HA terminal) manufactured by Dia Instruments Co., Ltd. was used, and the belt circumferential direction was measured at a pitch of 20 mm under conditions of 500 V and 10 seconds.
[0182]
Surface resistivity is 10¹³~ 1x10¹⁶As a sample to be Ω, a belt current direction was measured at a pitch of 100 mm under a condition of 500 V for 10 seconds using a microcurrent measuring device R8340A (JIS electrode) manufactured by Advantest Corporation.
[0183]
DSC
Using SSC-5200 (trade name) manufactured by Seiko Denshi Kogyo Co., Ltd., the measurement was performed at a heating rate of 10 ° C./min. One sample was DSC measured to 300 ° C., then cooled to room temperature at a rate of 10 ° C./min, and then the second DSC measurement was performed again under the same conditions, and the first melting peak temperature and the second time The difference from the melting peak temperature was determined.
・ Durability evaluation as an endless belt
The obtained endless belt was mounted on an image forming apparatus as an intermediate transfer belt, a transfer transfer belt, or a photosensitive belt, and images were continuously output. The number of sheets output was evaluated to determine whether cracks occurred in the endless belt.
・ Bending resistance (bending resistance)
In accordance with JISP-8115, the test piece was cut into a size of 15 mm in width and 100 mm in length, and MIT testing machine was bent at a rate of 175 times / minute, a rotation angle of 135 ° left and right, and a tensile load of 1.5 kgf. The number of breaks was measured.
・ Tensile modulus
In accordance with ISO R1184-1970, the test piece was cut to a width of 15 mm and a length of 150 mm, the tensile speed was 1 mm / min, and the distance between the grips was 100 mm.
・ Thickness
Measurement was performed at a pitch of 20 mm in the circumferential direction of the endless belt using a micrometer manufactured by Tokyo Seimitsu Co., Ltd.
・ Volume resistivity (Ω ・ cm)
Using a high resistance meter Hiresta HRS probe (manufactured by Dia Instruments Co., Ltd.), measurement was performed at a measurement voltage of 100 V and a measurement time of 10 seconds at a pitch of 20 mm in the circumferential direction of the endless belt.
[0184]
[Examples 1-7]
PBT, PC, tetrabutyl titanate, magnesium acetate, and a heat stabilizer were preliminarily dried at about 130 ° C. in advance, and then heated and kneaded to obtain material pellets.
[0185]
The heating and kneading conditions at this time are shown in Table 1, and the reaction in the kneader was suppressed.
[0186]
This material pellet was extruded to produce an endless belt.
[0187]
It should be noted that the extrusion conditions shown in Table 1 were set so that the reaction was accelerated to a preferable level in the extruder and an endless belt was obtained.
[0188]
Table 1 shows the form and characteristics of the endless belt.
[0189]
[Comparative Example 1]
An endless belt obtained under the same conditions as in Example 1 except that no polymerization catalyst was used.
[0190]
In order to remove the influence of the metal content in the resin as an impurity, PBT was once dissolved in a solvent, filtered using a column, and then the solvent was removed.
[0191]
Table 1 shows the forms and characteristics of the endless belts of Comparative Examples 1 and 2.
[0192]
[Comparative Example 2]
The kneading conditions and extrusion conditions were selected so that the sea-island structure did not occur. By setting the conditions shown in Comparative Example 2 in Table 1, an endless belt having a non-sea island structure in which PBT and PC were uniformly dispersed was manufactured.
[0193]
[Table 1]

[0194]
As shown in Table 1, each of the endless belts according to the examples of the present invention has a high tensile elastic modulus over a wide temperature range, excellent belt durability, and good flexibility. On the other hand, in Comparative Example 1 in which the polymerization catalyst was not added, cracks and image misalignment occurred with 60,000 sheets, and the bending resistance was insufficient. In Comparative Example 2, although the polymerization catalyst was added, the temperature at the time of kneading and molding was set to a high value and a non-sea island structure, so the difference between the first and second DSC melting temperatures was large. Therefore, the tensile elastic modulus in a high temperature region (60 ° C.) is small. As a result, 60,000 copies produced an image shift due to elongation of the endless belt.
[0195]
【The invention's effect】
As is clear from the above examples and comparative examples, according to the present invention, the tensile elastic modulus is high over a wide temperature range, the bending resistance, the chemical resistance and the molding dimensional stability are excellent. There are provided an endless belt in which deterioration of physical properties is suppressed, an image forming apparatus belt using the endless belt, and an image forming apparatus using the image forming apparatus belt.
[Brief description of the drawings]
FIG. 1 is an NMR chart of a mixed reaction product of PBT and PC.
FIG. 2 is an enlarged view of a portion II in FIG.
FIG. 3 is a side view of a conventional intermediate transfer apparatus.
[Explanation of symbols]
1 Photosensitive drum
2 Charger
3 Exposure optical system
4 Developer
5 Cleaner
6 Conductive endless belt
7, 8, 9 Transport roller

Claims (13)

A crystalline resin having at least one of a hydroxyl group, a carboxylic acid group and an ester bond, an amorphous resin having at least one of a hydroxyl group, a carboxylic acid group and an ester bond , a polymerization catalyst and a chelator are mixed by heating and molded. ,
The mass of the metal component in the polymerization catalyst is 10 to 500 ppm with respect to the total resin,
The amount of the chelator is 0.1 to 5 parts by weight with respect to 100 parts by weight of the resin,
The crystalline resin is PAT (polyalkylene terephthalate), and the amorphous resin is selected from PC (polycarbonate), PAr (polyarylate) and PMMA (polymethyl methacrylate),
The difference between the peak temperature indicating the melting peak due to the first temperature increase by DSC (differential scanning calorimetry) and the peak temperature indicating the melting peak due to the second temperature increase after cooling is 30 ° C. or less,
The bending resistance according to JIS P-8115 in the belt circumferential direction exceeds 5000 times,
The tensile elastic modulus at 40 ° C. is 60% or more of the tensile elastic modulus at 5 ° C .;
The tensile elastic modulus at 60 ° C. is 20% or more with respect to the tensile elastic modulus at 5 ° C.,
The surface electrical resistivity is 1 × 10 ¹ to 1 × 10 ¹⁶ Ω, or the volume electrical resistivity is 1 × 10 ¹ to 1 × 10 ¹⁶ Ω · cm, and one endless belt is used. The maximum value of the resistivity is not more than 100 times the minimum value;
An endless belt, wherein the resin constituting the endless belt has a sea-island structure. The endless belt according to claim 1 , wherein a chemical bond exists between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin. The endless belt according to claim 1 or 2 , wherein the weight ratio of the components satisfies the following conditions.
The weight ratio of crystalline resin / amorphous resin is 1/99 to 99/1.
The metal in the polymerization catalyst is 1 ppm to 10000 ppm relative to the weight of (crystalline resin + amorphous resin). The compounding ratio of the crystalline resin is X parts by weight, the polystyrene (PS) equivalent weight average molecular weight is Mw ₁ , the amorphous resin compounding ratio is Y parts by weight, the PS equivalent weight average molecular weight is Mw ₂ , the crystalline resin, amorphous The endless belt according to any one of claims 1 to 3 , wherein when the PS-converted weight average molecular weight of the resin composition obtained after heat-kneading the functional resin and the polymerization catalyst is Mw ₃ , the following relationship is satisfied: .

The endless belt according to any one of claims 1 to 4 , wherein the PS-converted weight average molecular weight is 130,000 or more. Endless belt according to any one of claims 1 to 5, characterized in that the polymerization catalyst contains Ti. The endless belt according to any one of claims 1 to 6 , wherein the polymerization catalyst contains at least one member selected from the group consisting of alkali metals, alkaline earth metals, and zinc, and Ti. The endless belt according to claim 7 , wherein the element of the group is Mg. The endless belt according to any one of claims 1 to 8 , wherein the crystalline resin is PBT (polybutylene terephthalate) . The endless belt according to any one of claims 1 to 9 , wherein the amorphous resin is PC (polycarbonate). Endless belt according to any one of claims 1 to 1 0, characterized in that it contains 3 to 30 wt% of carbon black as the conductive filler. It claims 1 to an image forming apparatus for the intermediate transfer belt consisting of an endless belt according to item 1 or one of the 1 1, the conveyed transfer belt, or the image forming apparatus belt is a photoreceptor belt. An image forming apparatus comprising an image forming apparatus belt according to claim 1 2.

Images