【発明の詳細な説明】[Detailed description of the invention]
本発明は、電子複写機等に於いて使用される定
着用加熱ロールに関するものである。更に詳しく
云えば、種々の電子写真プロセスによつて複写紙
上に形成されたトナー像を複写紙に定着する方法
として、発熱体から放射される輻射熱によりトナ
ーを加熱融着せしめる方法、加熱ロールと圧接ロ
ールの組み合わせよりなるニツプロールの間に複
写紙を通過させることによりトナーに熱及び圧力
を加えて加熱加圧融着せしめる方法等、各種の定
着方法が提案されているが、その中の加熱ロール
と圧接ロールにより定着する装置の加熱ロールに
関するものである。
従来、このような加熱ロールは熱伝導性の良い
材料、例えば金属類で形成された円筒状コアの表
面をポリテトラフロロエチレン樹脂（以下PTFE
と称す）の様なフツ素系樹脂やシリコーンゴム
等、非粘着性を有する材料で被覆したもので作ら
れており、トナーが加熱、加圧される時にトナー
の一部が加熱ロールに粘着し加熱ロールを汚染す
る現象を防止するようになつている。又、被覆さ
れた非粘着性を有する材料の非粘着性をより効果
的に機能させる目的及び複写紙の通過による摩耗
や加熱ロールの清掃に用いられるブレード、ウエ
ブ等との摩擦による摩耗を防止する目的でシリコ
ンオイルの様な離型剤を加熱ロールに塗布するこ
とも多い。
シリコンオイルの様な離型剤を塗布しない加熱
ロールで定着を行う場合、一般にフツ素系樹脂等
は他の樹脂に比較して優れた非粘着性を有する
が、耐摩耗性が十分でなく寿命が短かいという欠
点を有する。又一般にフツ素系樹脂等にガラス
粉、シリカ等を混合して耐摩耗性を良することも
行われるが、ガラス粉、シリカ等の混合量を増す
に従つて非粘着性が悪くなり、煩雑なオイル供給
システムを要するシリコンオイルの様な離型剤を
塗布する必要が生ずるという欠点を有する。これ
ら欠点を改良する目的で例えば特開昭54−109845
号の様にパーフロロアルコキシエチレン樹脂を用
いることが提案されている。この方法は効果的な
提案であるが一部のトナーに対する非粘着性が劣
る上耐摩耗性が十分でない。又、例えば特開昭55
−17182号の様にPTFE樹脂中の充填物、添加残
留物の量を５重量％未満とする提案もされている
が、PTFE樹脂中の塗装焼付後も残留する添加物
等の量、即ち顔料成分、塗料粘度調整成分、分散
液安定化剤等の無機成分の量を少くするとPTFE
塗料としての加工性が著しく劣るのでこれらの成
分を減少させることができず、従つてPTFEの耐
摩耗性付与を目的とした充填剤を１％程度しか充
填できないことになり、PTFEの耐摩耗性の欠点
を殆んど改良できないため実用性に乏しい。
本発明は、非粘着性を殆んど減ずることなく効
果的に耐摩耗性を付与する充填剤と樹脂との組成
物をコアに被覆して加熱定着ロールを提供せんと
するものであり、更にその結果としてシリコンオ
イルの様な離型剤を塗布する必要がなく非粘着性
と耐摩耗性の良い加熱定着ロールを提供すること
である。
第１図は通常の加熱ロール１２の断面図であ
り、加熱ロールは熱伝導性の良好な材料で作られ
たコア１の表面にフツ素系樹脂などを被覆加工し
て被覆層２を有している。
電子写真複写機の熱および圧力を利用して定着
を行うロール加熱式定着装置の例を第２図に示
す。第２図において加熱ロール１２はランプヒー
ター６により加熱され、その加熱量は温度センサ
ー７で検知される温度が常に一定になるように制
御される。複写紙８の上の未定着トナー像９は加
熱ロール１２と圧接ロール１１の間を通過し、加
熱および加圧作用により定着トナー１０の形で複
写紙に定着される。この際に複写紙の加熱ロール
からの剥離を助けるためにバネ４で押し付けられ
た剥離ツメ５が配置されている。更に微量のトナ
ーや紙の粉塵が加熱ロール表面を汚染することを
防止するため、ゴム等で作られたクリーニングブ
レード３がバネ４によつて加熱ロール表面に押し
付けられる。
本発明の加熱ロールは、そのコアを被覆する非
粘着性材料層として、フツ素系樹脂に研摩作用を
有する無機粉体で平均粒径が20μ以下である粉体
をフツ素系樹脂に対して１重量％以上、10重量％
以下の範囲で添加し塗工被覆してなる加熱ロール
である。ここで云う研摩作用を有する無機粉体と
は、ガラスやシリカより高い硬度を持つ無機粉体
で、新モース硬度で８以上のものであり、ダイヤ
モンド粉末、コランダム粉、ケイ石粉、人造ダイ
ヤ粉、窒化ホウ素、炭化ホウ素、炭化ケイ素、融
解アルミナ等の粉体等があるが、炭化ケイ素の様
な一般的な研摩材が実用的である。又、フツ素系
樹脂のコアへの被覆は厚さ20〜50μ程度であるこ
とが多く、従つて粉体の粒径は20μ以下であるこ
とが望ましい。
更に、フツ素系樹脂に対する研摩材粉体の添加
量は、１％未満では耐摩耗性に対する効果が殆ん
どみられず、10％を超えると非粘着性が悪くな
る。（PTFE樹脂の場合、顔料等の塗料として
PTFE樹脂成分以外に必然的に入つてくる成分が
５％程度あるため、PTFE樹脂以外の成分が合計
10％を超えると非粘着性が低化する）
本発明による硬度の高い研摩作用を有する無機
粉体のフツ素系樹脂に対する耐摩耗性の付与効果
が特に優れる理由の詳細は明らかでよいが、フツ
素系樹脂の中に埋まり一部分が表面に現れた粉体
が、摩耗を引き起こす相手（即ち紙やブレード、
剥離用ツメ等）との度重なる摩擦に於ても摩耗、
破損することなく、フツ素系樹脂系表面への紙や
ブレードの直接的な強い圧接、摩擦をさまたげて
いることによると考えられる。１％未満の含有量
では、表面に出ている研摩作用と有する無機粉体
の量が少なく、紙やブレードが直接強い圧接力で
フツ素系樹脂を摩擦するため摩耗が著しく、10％
を越える含有量では表面に現れる上記粉体の量が
多すぎて、フツ素系樹脂の非粘着性の表面積が相
対的に少なくなり非粘着性が悪化すると考えられ
る。
以下に本発明の加熱ロールの構成、被覆材料の
組成、及びそれによる効果を実施例により具体的
に説明する。
実施例 １
第２図に示された構成の定着装置の加熱ロール
のアルミニウム製コア円筒（直径約40mm）の表面
に、塗布焼付後に残留する成分（即ち顔料等）が
PTFE樹脂の他に、PTFE樹脂に対して約４重量
％である様なPTFE樹脂塗料（４％以下では
PTFEエナメルの加工性が悪い）に、PTFE樹脂
に対して１重量％の炭化ケイ素粉（新モース硬度
13；平均粒径5.2μ；不二見研摩材工業製、GC−
＃3000）を添加して通常のPTFE樹脂塗料の塗
工、焼付方法によりコア円筒を被覆し、バフ研摩
仕上げして加熱ロールを製作した。この加熱ロー
ルを用いて、テフロン（登録商標）コートしたア
ルミニウム製の剥離用ツメを先端で300ｇの荷重
で押しあてて２×106回転させPTFE被覆を摩耗
させて摩耗深さを測定した。又、同じ加熱ロール
に硬度約70度のかたいフツ素ゴムブレードを強く
押しあてて１×105回転させ、摩耗による表面の
粗さを視覚的に判定した。又、二種のトナーを用
い加熱ロール表面の非粘着性をシリコーンオイル
等を用いないでロール表面の汚れで判定した。い
ずれも加熱ロールの温度は190℃であつた。その
結果を表１に示す。
実施例 ２
実施例１のうちの炭化ケイ素粉の量を３重量％
とした他は実施例１と同様にし、同様の測定を行
つた。
実施例 ３
実施例１のうちの炭化ケイ素粉の量を５％とし
た他は実施例１と同様にし、同様の測定を行つ
た。
実施例 ４
実施例１のうちの炭化ケイ素粉をアルミナ粉
（コランダム；新モース硬度12；平均粒径7μ）を
用いた他は実施例１と同様にし、同様の測定を行
つた。
実施例 ５
実施例１のうちのPTFE樹脂塗料をパーフロロ
アルコキシエチレン樹脂の粉体塗装用塗料
（PFA；三井フロロケミカル(株)製、MP−10）と
した他は実施例１と同様にし、同様に測定を行つ
た。
比較例 １
実施例１のうちの炭化ケイ素の量を0.5重量％
及び７重量％とした他は実施例１と同様にし、同
様に測定を行つた。
比較例 ２、３、４
実施例１、２、３のうちの炭化ケイ素をシリカ
粉（新モース硬度７；平均粒径15μ）とした他は
実施例１と同様にし、同様に測定した。
以上の結果を表１にまとめて示すが、実施例１
〜５の本発明による加熱ロールの耐摩耗性が、良
好な耐摩耗性及び非粘着性を有することがわか
る。
The present invention relates to a heating roll for fixing used in electronic copying machines and the like. More specifically, as a method for fixing toner images formed on copy paper by various electrophotographic processes, there are methods of heating and fusing the toner with radiant heat emitted from a heating element, and methods of heat-fusing the toner with a heating roll. Various fixing methods have been proposed, such as a method in which copying paper is passed between nip rolls made up of a combination of rolls, and heat and pressure is applied to the toner to fuse it under heat and pressure. The present invention relates to a heating roll of a device that performs fixing using a pressure roll. Conventionally, such heating rolls have a cylindrical core made of a material with good thermal conductivity, such as metal, and the surface of the core is made of polytetrafluoroethylene resin (hereinafter referred to as PTFE).
It is made of a material coated with a non-adhesive material such as fluorocarbon resin or silicone rubber, and when the toner is heated and pressurized, some of the toner sticks to the heated roll. This is designed to prevent the phenomenon of contaminating the heating roll. In addition, the purpose is to make the non-adhesive properties of the coated non-adhesive material work more effectively and to prevent abrasion caused by passing copy paper and friction with blades, webs, etc. used for cleaning heating rolls. For this purpose, a release agent such as silicone oil is often applied to the heating roll. When fixing is performed using a heated roll without applying a release agent such as silicone oil, fluorine-based resins generally have superior non-stick properties compared to other resins, but their wear resistance is insufficient and their lifespans are shortened. It has the disadvantage of being short. Generally, glass powder, silica, etc. are mixed with fluororesin to improve wear resistance, but as the amount of glass powder, silica, etc. This method has the disadvantage that it becomes necessary to apply a mold release agent such as silicone oil, which requires a detailed oil supply system. For the purpose of improving these drawbacks, for example, Japanese Patent Application Laid-Open No. 54-109845
It has been proposed to use perfluoroalkoxyethylene resin as shown in No. Although this method is an effective proposal, it has poor non-adhesion to some toners and does not have sufficient abrasion resistance. Also, for example, Japanese Patent Application Publication No. 1983
-17182, it has been proposed to reduce the amount of fillers and additive residues in PTFE resin to less than 5% by weight, but the amount of additives, etc. that remains even after painting baking in PTFE resin, that is, pigments. When the amount of inorganic components such as paint viscosity adjusting components and dispersion stabilizers is reduced, PTFE
It is not possible to reduce these components because the processability as a paint is extremely poor, and therefore only about 1% of the filler, which is intended to impart wear resistance to PTFE, can be filled, which reduces the wear resistance of PTFE. It is of little practical use as it cannot improve the shortcomings of The present invention aims to provide a heat fixing roll whose core is coated with a composition of a filler and a resin that effectively imparts wear resistance without substantially reducing non-tackiness; As a result, it is an object of the present invention to provide a heat fixing roll that does not require the application of a release agent such as silicone oil and has good non-adhesion and abrasion resistance. FIG. 1 is a cross-sectional view of a typical heating roll 12, which has a core 1 made of a material with good thermal conductivity and a coating layer 2 formed by coating the surface with a fluorocarbon resin or the like. ing. FIG. 2 shows an example of a roll heating type fixing device that performs fixing using the heat and pressure of an electrophotographic copying machine. In FIG. 2, the heating roll 12 is heated by a lamp heater 6, and the amount of heating is controlled so that the temperature detected by the temperature sensor 7 is always constant. The unfixed toner image 9 on the copy paper 8 passes between a heating roll 12 and a pressure roll 11, and is fixed to the copy paper in the form of a fixed toner 10 by heating and pressure. At this time, a peeling claw 5 pressed by a spring 4 is arranged to help peel the copy paper from the heating roll. Furthermore, in order to prevent minute amounts of toner and paper dust from contaminating the heating roll surface, a cleaning blade 3 made of rubber or the like is pressed against the heating roll surface by a spring 4. The heating roll of the present invention uses an inorganic powder that has an abrasive action on the fluorocarbon resin and has an average particle size of 20μ or less as a non-adhesive material layer covering the core of the heating roll. 1% by weight or more, 10% by weight
This heating roll is coated with the following additives. The inorganic powder with an abrasive action mentioned here is an inorganic powder that has a hardness higher than that of glass or silica, and has a hardness of 8 or more on the new Mohs scale, and includes diamond powder, corundum powder, silica powder, artificial diamond powder, Powders such as boron nitride, boron carbide, silicon carbide, and fused alumina are available, but common abrasive materials such as silicon carbide are practical. Further, the coating of the fluorocarbon resin on the core is often about 20 to 50 microns thick, so it is desirable that the particle size of the powder is 20 microns or less. Furthermore, if the amount of abrasive powder added to the fluorocarbon resin is less than 1%, there will be little effect on wear resistance, and if it exceeds 10%, non-adhesion will deteriorate. (In the case of PTFE resin, it can be used as a paint such as pigment.
There are about 5% of components that inevitably come in other than the PTFE resin component, so the total amount of components other than PTFE resin is
(If the amount exceeds 10%, the non-adhesive property will decrease.) The details of why the inorganic powder having a high hardness abrasive action according to the present invention has a particularly excellent effect of imparting wear resistance to fluororesin are clear, but Powder that is buried in the fluororesin and partially exposed on the surface is exposed to objects that cause wear (i.e., paper, blades, etc.).
Repeated friction with peeling claws, etc.) will also cause wear and tear.
This is thought to be due to the direct strong pressure contact and friction of the paper or blade to the fluororesin surface without causing damage. If the content is less than 1%, the abrasive action on the surface and the amount of inorganic powder present are small, and the paper or blade directly rubs the fluororesin with strong pressure, resulting in significant wear.
It is thought that if the content exceeds 100%, the amount of the powder appearing on the surface will be too large, and the non-adhesive surface area of the fluororesin will become relatively small, resulting in poor non-adhesive properties. EXAMPLES Below, the structure of the heating roll of the present invention, the composition of the coating material, and the effects thereof will be specifically explained with reference to Examples. Example 1 Components (i.e., pigments, etc.) remaining after coating and baking were removed from the surface of the aluminum core cylinder (diameter approximately 40 mm) of the heating roll of the fixing device configured as shown in FIG.
In addition to PTFE resin, PTFE resin paints containing approximately 4% by weight of PTFE resin (less than 4%
1% by weight of silicon carbide powder (new Mohs hardness) based on PTFE resin.
13; Average particle size 5.2μ; Manufactured by Fujimi Abrasive Industry, GC-
#3000) was added, the core cylinder was coated using the usual PTFE resin coating and baking method, and the heating roll was finished by buffing. Using this heated roll, a Teflon (registered trademark) coated aluminum peeling claw was pressed against the tip with a load of 300 g and rotated 2 x 10 6 times to abrade the PTFE coating and measure the depth of wear. In addition, a hard fluororubber blade with a hardness of about 70 degrees was strongly pressed against the same heating roll and rotated for 1×10 5 revolutions, and the surface roughness due to wear was visually determined. Furthermore, using two types of toner, the non-adhesiveness of the heated roll surface was determined based on the dirt on the roll surface without using silicone oil or the like. In both cases, the temperature of the heating roll was 190°C. The results are shown in Table 1. Example 2 The amount of silicon carbide powder in Example 1 was changed to 3% by weight.
Other than that, the same procedure as in Example 1 was carried out, and the same measurements were performed. Example 3 The same procedure as in Example 1 was carried out except that the amount of silicon carbide powder in Example 1 was changed to 5%, and the same measurements were performed. Example 4 The same measurements as in Example 1 were carried out, except that alumina powder (corundum; new Mohs hardness: 12; average particle size: 7 μm) was used as the silicon carbide powder. Example 5 The same procedure as in Example 1 was carried out, except that the PTFE resin paint in Example 1 was replaced with a perfluoroalkoxyethylene resin powder coating paint (PFA; manufactured by Mitsui Fluorochemical Co., Ltd., MP-10). Measurements were made in the same manner. Comparative Example 1 The amount of silicon carbide in Example 1 was reduced to 0.5% by weight.
The same procedure as in Example 1 was carried out except that the content was 7% by weight, and the measurements were carried out in the same manner. Comparative Examples 2, 3, 4 The same procedures as in Example 1 were carried out, except that the silicon carbide in Examples 1, 2, and 3 was replaced with silica powder (new Mohs hardness: 7; average particle size: 15 μm), and measurements were conducted in the same manner. The above results are summarized in Table 1, and Example 1
It can be seen that the abrasion resistance of the heating roll according to the present invention of No. 5 to 5 has good abrasion resistance and non-adhesion.
【表】【table】
【表】
よび比較 フツソ 高硬度無機 機物含 以外
の成分 トナ トナ フインガーに による摩
例 系樹脂 粉 添加量 有量 の合
計割合 ー ー よる摩耗量 耗の程度
[Table] and comparison Ingredients other than high hardness inorganic and organic materials Tona Tona Friction example due to finger Resin powder Amount added Total percentage of amount - - Amount of wear caused by - Degree of wear