JP3678779B2 - Roll for fixing unit - Google Patents

Description

【００２９】
【表２】

【００３０】
上記「表１」により、比較例１〜４の場合は逆クラウン量が小さくなるにつれてカール及びシワの発生枚数が多くなることが判明した。これに対し、「表２」からは、逆クラウン量がほとんどない場合（０．０mmの場合）、本実施例１〜３では若干のカール及びシワの発生が確認されたが、逆クラウン量が０．１〜０．３mmの場合、本実施例４〜12ではカール及びシワの発生が全くなかった。これにより、本発明が比較例と比べて優れていることが明らかになった。
【００３１】
【発明の効果】
以上詳述したようにこの発明によれば、小型，軽量，低電力，低温定着が可能となるとともに、未定着画像を定着する際に紙等のカール及びシワの発生のない定着器用ロールを提供できる。
【図面の簡単な説明】
【図１】一般的な定着器用ロールの模式図。
【図２】ＰＦＡフッ素樹脂チューブ被覆シリコーンゴムスポンジゴムロールの断面図。
【図３】図２に要部の拡大図。
【図４】左右対称等間隔スリットの模式図。
【図５】左右対称不等間隔スリットの模式図。
【図６】傾斜スリットの模式図。
【図７】本発明に係る定着器用ロールの効果の説明図。
【図８】本発明に係る定着器用ロールにおける逆クラウン量の説明図。
【符号の説明】
１…紙、 ２…未定着トナー、 ３…加熱ロール、
４…加圧ロール、 ５…定着トナー、 ６…ヒータ、
７…芯金、 11，13…接着剤層、 12…シリコーンスポンジ層、
14…フッ素樹脂チューブ、 41，51，61…スリット。[0001]
[Industrial application fields]
The present invention relates to a roll for a fixing device, and more particularly to a roll for a fixing device for thermally fixing an unfixed image on a recording material such as paper in an electrophotographic copying machine, an electronic printer or the like.
[0002]
[Prior art]
Conventionally, as shown in FIG. 1, a fixing device in an electrophotographic copying machine nips an unfixed toner 2 on a paper 1 by a heating roll 3 and a pressure roll 4 and heat-fixes the fixing toner 5 on the paper 1 The method of making it is common. In FIG. 1, reference numeral 6 denotes a heater provided on the heating roll 3, and reference numerals 7 and 8 denote a core metal and a silicone sponge layer that constitute the pressure roll 4, respectively.
[0003]
In recent years, with the reduction in weight, size and power consumption, as shown in FIGS. 2 and 3 (partially detailed view of FIG. 2), the silicone rubber sponge layer 12 is disposed on the cored bar 7 via the adhesive layer 11. Further, a rubber roll having a structure in which a fluororesin tube 14 having a thickness of 50 to 70 μm as a surface layer is provided on the sponge layer 12 via an adhesive layer 13 is used. Here, the fluororesin tube 14 is provided to improve the durability of the rubber roll surface in contact with the toner. As the material of the fluororesin tube 14, Teflon (trade name) manufactured by DuPont and PFA resin (perfluoroalkyl vinyl ether resin) are generally used.
[0004]
The rubber roll having the two-layer structure shown in FIG. 2 has advantages such as a high nip, a low load, and downsizing, and is widely used. In addition, the silicone rubber sponge layer of the rubber roll can be made conductive, or the fluororesin tube can be made conductive. A rubber roll having such conductivity has been put to practical use.
[0005]
The rubber roll of FIG. 2 is generally manufactured as follows. First, a general peroxide-crosslinked silicone rubber is subjected to tubing by a typical foam rubber extruder, and a silicone sponge rubber tube is obtained through heat foaming. Next, an adhesive is applied to the core metal, and the tube is fixedly adhered to the core metal. Subsequently, the surface of the rubber roll is polished by grinding and finished to a predetermined outer diameter. Next, an adhesive is applied to the surface of the ground silicone sponge rubber layer, and a fluororesin tube is covered on the outer periphery to complete a rubber roll having a two-layer structure as shown in FIG. Here, the inner surface of the fluororesin tube is processed to a surface that can be bonded by a metal sodium-naphthalene method, an ammonia method, a sputter etching method, or the like.
[0006]
[Problems to be solved by the invention]
Generally, in a fixing device such as an electrophotographic copying machine, in order to perform heat fixing, in order to fix toner by heating to 150 ° C. to 230 ° C., the sponge rubber roll causes an initial fluctuation such as a regular crown shape due to thermal expansion. . When paper or the like is passed through the fixing device in this state, the paper or the like is curled and wrinkled.
[0007]
In order to prevent these curls and wrinkles, a sponge rubber roll is usually ground and used in an inverted crown shape. However, this method works effectively when the hardness of the sponge rubber roll is high. However, when the hardness is low, for example, with an Asker C sponge hardness meter of 30 degrees or less, curl and wrinkles are generated even in the inverted crown shape. Has the problem of being unavoidable.
[0008]
Therefore, a method of increasing the reverse crown amount can be considered. Generally, the reverse crown amount is a value obtained by grinding to 0.15 mm or less. However, when this value is increased, the toner in the central portion of paper or the like becomes an unfixed image and becomes unusable.
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances. A roll for a fixing device that can be fixed in a small size, light weight, low power, and low temperature and does not generate curling and wrinkling of paper or the like when fixing an unfixed image. The purpose is to provide.
[0010]
[Means for Solving the Problems]
The present invention relates to a roll for a fixing device comprising a sponge rubber layer fixed to a peripheral surface of a core metal and a fluororesin coating layer fixed to the outer peripheral surface of the sponge rubber layer via an adhesive layer. Distributing between sponge rubber layers due to the presence of the slit during pressure rotation by providing a continuous spiral slit with symmetrical central distribution from the center to both ends inside the rubber layer. It is a roll for a fixing device characterized in that an inclined attractive force acts on the portion .
[0011]
In the present invention, a spiral slit that is continuous from the center toward both ends is provided inside the sponge rubber layer, because paper or the like is stretched from the center of the roll toward both ends by the pressure rotation during fixing. This is to suppress the curling and wrinkling of paper and the like by the effect (screw effect). Here, the continuous spiral slits include the case where the slits are equally spaced (FIG. 4), the case where the slits are unevenly spaced toward both ends (FIG. 5), and the core. Three types of inclined spiral structures (FIG. 6) formed at an angle with respect to the axial direction of gold and combinations thereof are conceivable.
[0012]
Silicone rubber is generally used for the sponge rubber layer, but any other heat-resistant rubber such as EPDM rubber, fluorine rubber, nitrile rubber, chloroprene rubber, epichlorohydrin rubber, NBR rubber can be used. There are no particular restrictions on conductivity, thermal conductivity, dielectric constant characteristics, electric resistance, sponge hardness, foaming degree, outer shape of sponge rubber layer, and the like. Further, there may be a through hole in the longitudinal direction of the sponge rubber layer. Furthermore, the shape of the spiral slit formed in the sponge rubber layer is formed symmetrically from the center to the end, but the center thereof may be varied. This is because the center value of the roll fluctuates depending on the size of the paper, and even if it fluctuates slightly toward the end from the center, it can be fully used.
[0013]
[Action]
According to the present invention, an inclined attractive force is exerted from the central portion toward both ends by a spiral slit formed symmetrically inside the sponge rubber layer formed on the core metal, thereby curling paper and the like. Generation of wrinkles can be suppressed. That is, as shown in FIG. 7, the sponge rubber layer 12 is fixed to the fluororesin tube layer 14 by the adhesive layer 13, and the same sponge rubber layer 12 is fixed to the core metal 7 by the adhesive layer 11. I understand that.
For this reason, a displacement occurs between the sponges 16a and 16b due to the presence of the free spiral slit 15 in the pressure rotation deformation. This deviation and rotation action enables paper running without curling and wrinkling. Here, it does not depend on the depth of the spiral slit, that is, whether or not the slit reaches the core metal.
[0014]
【Example】
Hereinafter, an embodiment of the present invention will be described.
The fixing device roll according to the present invention was manufactured as follows.
Silicone rubber (trade name: KE903U, manufactured by Shin-Etsu Chemical Co., Ltd.) 100 parts by weight of vulcanizing agent for silicone rubber (trade name: C-1, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight of vulcanizing agent for silicone rubber (Product name: C-3, manufactured by Shin-Etsu Chemical Co., Ltd.) 3 parts by weight Foaming agent for silicone rubber (Product name: KEP-13, manufactured by Shin-Etsu Chemical Co., Ltd.) 2 parts by weight Thoroughly mix the above compound A silicone rubber compound was obtained.
[0015]
Next, this silicone rubber compound was heated and foamed and cured at 250 ° C. for 20 minutes using a rubber extruder and a heating furnace to obtain a hollow silicone rubber tube having an inner diameter of 9 mm and an outer diameter of 22 mm. Subsequently, this silicone rubber tube was inserted and bonded to a core metal having an outer diameter of φ10 mm via an adhesive to form a sponge rubber roll.
[0016]
Next, the sponge rubber roll was polished to an outer diameter of 20 mm to obtain a sponge rubber roll having a straight surface. Subsequently, KE42RTV manufactured by Shin-Etsu Chemical Co., Ltd. was uniformly applied to the surface of this sponge rubber roll, and then a PFA fluororesin tube having an inner diameter of φ19.5 mm and a thickness of 50 μm was inserted to obtain a roll having a predetermined outer diameter of φ20 mm. . The hardness of this sponge rubber roll was 32 ° with Asker C.
[0017]
Further, the sponge rubber roll before polishing was polished into reverse crown amounts of 0.1 mm, 0.2 mm, and 0.3 mm, respectively, to obtain sponge rubber rolls. Here, the reverse crown amount can be described with reference to FIG. 8. The roll diameter at the distance L ₁ from one end of the roll is D ₁ , and the roll diameter at the distance L ₂ from the other end is If D ₂ , the roll diameter at the roll center is D ₃ , and the total length of the roll is L, then the reverse crown amount = D ₁ −D ₃ = D ₂ −D ₃ . However, L ₁ and L ₂ are both about 10% of L.
[0018]
Including these reverse crown rolls and surface straight polished sponge rubber rolls before PFA tube coating, the following slits were applied, and the surface coating layer was fixed to these through an adhesive as described above, and these were applied to Examples 1-12. It was. Moreover, the roll which does not give a slit was produced similarly, and these were set as Comparative Examples 1-4.
[0019]
(A) Slits with symmetrical equidistant pitch (FIG. 4). Here, the symbols a, b, c and d indicate the distance between the slits at the edge of the sponge rubber layer along the axial direction of the cored bar.
(B) Slits with left-right symmetric non-uniform pitch (FIG. 5). Here, the symbols a to d are the same as described above.
[0020]
(C) Surface inclined slits with symmetrical equidistant pitch (FIG. 6). In FIG. 6, the x-axis indicates the surface length direction, the y-axis indicates the circumferential direction, and the z-axis indicates the thickness of the sponge rubber layer, which are orthogonal to each other.
[0021]
Subsequently, KE42RTV manufactured by Shin-Etsu Chemical Co., Ltd. was uniformly applied to the surface of these sponge rubber rolls, and then a PFA fluororesin tube having an inner diameter of 19.5 mm and a thickness of 50 μm was inserted, and a roll 12 having a predetermined outer diameter of φ20 mm was inserted. The kind was obtained and these were made into Examples 1-12. All of these roll hardnesses were 32 ° in Asker C. In addition, four types of rolls in which a PFA tube was covered with a sponge rubber roll that was different from the above example only in that no slit was provided were similarly prepared, and these were designated as Comparative Examples 1 to 4.
[0022]
The slit of the sponge rubber roll is formed by rotating the sponge rubber roll on a lathe, applying a knife to the surface of the sponge rubber roll, moving the knife so as to cut the screw from the center to the end, and then removing the sponge rubber roll. Inversion was performed by similarly slitting from the center toward the other end. At this time, a sponge rubber roll having the slits (A) to (C) was obtained by controlling the moving speed or angle of the knife. In (C) above, the practical angle is considered to be within 5 °.
[0023]
The configuration of the 16 types of fixing device rolls thus obtained is as follows. The rolls for fixing devices according to Examples 1, 4, 7, and 10 are provided with a PFA fluororesin tube 14 on a cored bar 7 with a silicone sponge layer 11 interposed therebetween, and are symmetrical with respect to the silicone sponge layer 11 at an equal interval pitch. The slit 41 is provided, and the reverse crown amounts are 0.0, 0.1, 0.2, and 0.3, respectively.
[0024]
Further, in the fixing device rolls according to Examples 2, 5, 8, and 11, the PFA fluororesin tube 14 is provided on the core metal 7 via the silicone sponge layer 11, and the silicone sponge layer 11 is symmetrical and unequal. The structure is provided with slits 51 having an interval pitch, and the reverse crown amounts are 0.0, 0.1, 0.2, and 0.3, respectively.
[0025]
Further, in the fixing device rolls according to Examples 3, 6, 9, and 12, the PFA fluororesin tube 14 is provided on the core metal 7 via the silicone sponge layer 11, and the silicone sponge layer 11 is symmetrically spaced at equal intervals. A pitch inclined slit 61 is provided, and the reverse crown amounts are 0.0, 0.1, 0.2, and 0.3, respectively.
[0026]
The rolls for fixing devices according to Comparative Examples 1, 2, 3, and 4 have a configuration in which a PFA fluororesin tube 14 is provided on a cored bar 7 through a normal silicone sponge layer 11 having no slits, and the reverse crown amount. Are 0.0, 0.1, 0.2 and 0.3, respectively.
[0027]
The results of the paper passing test of the PFA fluororesin tube-covered silicone rubber roll produced as described above are shown in the following “Table 1” and “Table 2”. Here, Table 1 shows the result of the 3000 sheet passing test according to Comparative Examples 1 to 4, and Table 2 shows the result of the 3000 sheet passing test according to Examples 1 to 12.
[0028]
[Table 1]

[0029]
[Table 2]

[0030]
From the above “Table 1”, it was found that in Comparative Examples 1 to 4, the number of curls and wrinkles increased as the reverse crown amount decreased. On the other hand, from Table 2, when there was almost no reverse crown amount (in the case of 0.0 mm), the occurrence of slight curl and wrinkles was confirmed in Examples 1 to 3, but the reverse crown amount was In the case of 0.1 to 0.3 mm, in Examples 4 to 12, there was no curl or wrinkle. This revealed that the present invention is superior to the comparative example.
[0031]
【The invention's effect】
As described above in detail, according to the present invention, there is provided a fixing device roll that can be fixed in a small size, light weight, low power, and low temperature, and is free from curling and wrinkling of paper or the like when fixing an unfixed image. it can.
[Brief description of the drawings]
FIG. 1 is a schematic view of a general fixing device roll.
FIG. 2 is a cross-sectional view of a PFA fluororesin tube-coated silicone rubber sponge rubber roll.
FIG. 3 is an enlarged view of the main part in FIG. 2;
FIG. 4 is a schematic view of symmetrical left and right symmetrical slits.
FIG. 5 is a schematic diagram of a symmetrical left-right symmetric slit.
FIG. 6 is a schematic diagram of an inclined slit.
FIG. 7 is an explanatory diagram of the effect of the fixing device roll according to the present invention.
FIG. 8 is an explanatory diagram of a reverse crown amount in the fixing device roll according to the present invention.
[Explanation of symbols]
1 ... paper, 2 ... unfixed toner, 3 ... heating roll,
4 ... Pressure roll, 5 ... Fixing toner, 6 ... Heater,
7 ... Core, 11,13 ... Adhesive layer, 12 ... Silicone sponge layer,
14… Fluororesin tube, 41, 51, 61… Slit.

Claims (3)

In a fixing device roll comprising a sponge rubber layer fixed to a peripheral surface of a core metal and a fluororesin coating layer fixed to the outer peripheral surface of the sponge rubber layer via an adhesive layer, the inside of the sponge rubber layer By providing a continuous spiral slit with a central distribution symmetrical from the center to both ends, a gap occurs between the sponge rubber layers due to the presence of the slit during pressure rotation, and an inclined attractive force from the center to both ends. A roll for a fixing device, characterized in that works . 2. The roll for a fixing device according to claim 1, wherein the spiral slit is a uniform slit having a constant pitch with respect to the axial direction of the core metal or a continuous slit having a non-uniform pitch. 3. The roll for a fixing device according to claim 1, wherein the spiral slit is inclined at a surface angle with respect to the axial direction of the cored bar.

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