JP3261166B2 - Toner fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner fixing device used in an electrophotographic copying machine and a printer, and more particularly to a roll for fixing toner.

[0002]

2. Description of the Related Art The demand for higher copying speeds in electrophotographic copying machines and printers is increasing with the spread of office automation in recent years. In electrophotographic copiers and printers, the factor that determines the copying speed is mainly the step of visualizing the electric latent image on the copy paper. That is, in an electrophotographic copying machine and a printer, a toner is fixed to an electric latent image on copy paper to obtain a visible image. In order to fix the toner, it is generally necessary to apply heat, pressure or heat and pressure.

In order to increase the copying speed, in recent years, devices using both a heat and pressure system for fixing toner have become dominant in the market. In particular, a method is known in which heat and pressure are simultaneously applied by passing copy paper between upper and lower rolls to fuse and fix toner on the copy paper. According to this method, a heat source is incorporated in the upper roll to function as a heat roll, and the lower roll has a role as a support roll or a counter roll. In order to prevent the molten toner from adhering to the roll at the time of fixing the toner, a material having excellent releasability is selected for the material of the upper and lower rolls. Known representatives of such materials are polytetrafluoroethylene (hereinafter also referred to as "PTFE") and silicone rubber.
For example, JP-B-57-52574, JP-B-59-13
No. 731 and JP-B-60-17109 describe a roll having a surface coated with PTFE or relatively hard silicone rubber as a roll for a toner fixing device, and a roll using a metal tube itself.

[0004] However, these materials have low heat resistance, so that the surface temperature of the roll cannot be set high or it is difficult to maintain the surface temperature. As a result, the fixing speed of the toner cannot be increased, so that there is a limit in increasing the copying speed.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an electrophotographic copying machine having a roll made of a material having excellent heat resistance and excellent heat insulation, release properties and abrasion resistance. An object of the present invention is to provide a toner fixing device for a printer. Still another object of the present invention is to provide a toner fixing device having a roll having a layer containing polybenzimidazole (hereinafter also referred to as “PBI”) having a releasability equal to or higher than that of a fluororesin roll. I do.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an electrophotographic copying machine and a toner fixing device for a printer according to the present invention provide a heat roll having a layer containing polybenzimidazole and / or an electronic roll having a counter roll. A toner fixing device for a photocopier and a printer, wherein the layer contains a high molecular fluorine compound and / or a low molecular fluorine compound.

[0007] The PBI used in the hot roll and / or counter roll of the present invention is a stable heterocyclic polymer, and its method of preparation is described in a number of US patents, including US Reissue Pat.
No. 6,065, U.S. Pat. Nos. 3,313,783, 3,5
09,108,3,518,234,3,555,38
9, 3,433,772, 3,408,336, 3,5
78,644, 3,549,603, 3,708,43
9,4,154,919,4,312,976,4,3
77,546,4 and 549,388. Also, a method for manufacturing PBI is described in J. Org. P. Crickl
ey, G .; J. Knight and W.W. W. Wright
Author, "Heat-Resistant Polymers-Technically Useful Materials (Heat-
Resistant Polymers-Techno
logically Useful Material
s) "Plenum Press, New York
(1983), pages 259-322.

The PBI preferably used for the hot roll and / or the counter roll of the present invention is poly-2,2 '-(m-phenylene) -5,5'-bibenzimidazole represented by the following structural formula: The deformation temperature of the PBI is 435 ° C., and the heat resistance is significantly higher than that of PTFE or silicone rubber. As a result, the set temperature of the heat roll can be increased, and the copying speed can be increased. The PBI has a wear coefficient of 29 at 100 hours and PV = 50000, and has excellent wear resistance, and is suitable as a material for a roll through which copy paper passes at high speed. The PBI used in the present invention has a number average molecular weight of 2,000 to 100,
000. Preferably, the PBI has a number average molecular weight of 5,
000 to 30,000. A method for producing a PBI sintered body is disclosed in Japanese Patent Application Laid-Open No. 1-99,818. For example, the sintered body is Hoechst Celan
It is commercially available as Celazole (registered trademark) of Ese Corporation, and a liquid in which PBI is dissolved in a solvent has also been developed.

As described above, in the heat roll and / or the counter roll used in the toner fixing device for an electrophotographic copying machine and a printer according to the present invention, the layer containing PBI is made of a polymer fluorine compound or a low molecular fluorine compound. including. By including such a fluorine compound in the layer containing PBI, the releasability between the toner fixing roll and the copy paper can be improved.

The high molecular fluorine compound referred to in the present invention broadly refers to a homopolymerization or copolymerization of a fluorine-containing monomer or a copolymer of a fluorine-containing monomer and another monomer. Examples of such a polymer fluorine compound include polytetrafluoroethylene, polytrifluorochloroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polydichlorodifluoroethylene. Preferably,
In the present invention, polytetrafluoroethylene is used. Particularly preferably, fine-particle PTFE (Hostaflon TF9202 and TF9205 (registered trademark)) manufactured or sold by Hoechst AG or copolymerized fluororesin H
Ostaflon TF1700 is used.

[0011] The low molecular fluorine compound referred to in the present invention refers to an inorganic or organic compound containing a fluorine atom. Preferably, the low molecular fluorine compound is a fluorinated hydrocarbon having up to 20 carbon atoms. The fluorinated hydrocarbon may be substituted with another functional group, for example, an alkoxy group, an alkenyl group, an aryl group, an aryl, an oxy group, a hydroxyl group, a carboxyl group, an acyl group, an amino group, a nitro group, a halogen, or the like. Good. Particularly preferably, an aliphatic fluoromonomer (Fluowet (registered trademark)) manufactured and sold by Hoechst AG is used as the low molecular fluorine compound.

Further, in the present invention, a hot roll and / or
The above-mentioned polymer fluorine compound and low molecular fluorine compound may be simultaneously contained in the layer containing PBI of the pair roll.

Further, in the present invention, a hot roll and / or
In addition to the above-mentioned fluorine compound, the layer containing PBI of the pair roll may contain an internal filler. PB
By adding an internal filler to the layer containing I, the self-lubricating property and electric conductivity of PBI can be improved.
Such an internal filler is, for example, carbon such as SiC, various metal powders, and graphite. By improving the self-lubricating property, the passability of the copy paper between the rolls is improved, and by improving the electrical conductivity, generation and accumulation of static electricity due to friction between the roll, paper and toner are prevented. For example, by internally adding graphite to PBI,
The volume resistivity of BI can be reduced to 10 ⁶ to 10 ¹⁴ Ωcm.

Although PBI has a very high surface hardness of 110 on the Rockwell hardness K scale, the elasticity and surface hardness can be improved by adding a binder resin material to the layer containing PBI. By improving the elasticity and surface hardness, the contact area between the hot roll and the roll,
That is, it is possible to give the nip width a degree of freedom and control the fixing efficiency of the toner. Such a binder resin material is, for example, an HTV (High Temperature).
Vulcanized) silicone rubber, RTV (Ro)
om Temperature Vulcanize
d) Silicone rubber, LTV (Low Tempera)
cure vulcanized) silicone rubber.

An embodiment of a hot roll and / or a pair roll used in a toner fixing device for an electrophotographic copying machine and a printer according to the present invention will be described below with reference to the drawings. However, they do not limit the scope of the invention. In the drawing, 1 is a heat source for fixing the toner, 2 is a layer containing PBI and a high molecular weight fluorine compound or / and a low molecular weight fluorine compound, 3 is a core tube, 4 is an outermost layer, 5 is an intermediate layer, 6 is a silicone rubber layer, and 7 is a PTFE layer.

As the heat roll used in the toner fixing device of the present invention, as shown in FIG. 1, a sintered body of a mixture of PBI and a high molecular fluorine compound and / or a low molecular fluorine compound may be used. As described above, since PBI has excellent heat resistance, the surface temperature of the heat roll can be set high, and the copying speed can be increased. Further, the mixture may be used together with an internal filler or / and a binder resin material. Further, the heat roll of the present invention is shown in FIGS.
May have a layered structure as shown in FIG.

That is, in the heat roll shown in FIG. 2, in addition to PBI and a high molecular weight fluorine compound and / or a low molecular weight fluorine compound, an internal filler or / and / or a binder resin substance is added to the surface of a core tube 3 made of aluminum. PBI layer 2 to be contained. By having such a structure of the heat roll, the heat roll used in the toner fixing device of the present invention can cover the heat resistance of aluminum, PTFE and silicone rubber while covering the disadvantages of aluminum, PTFE and silicone rubber, which are inferior in abrasion.
The releasability of the FE is maintained. As a result, the heat roll has excellent abrasion resistance and heat resistance, and has high releasability from copy paper, so that a higher copy speed and a longer continuous copy time can be achieved. .

FIG. 3 shows a core tube 3 made of aluminum.
A release agent such as PTFE or silicone rubber as the outermost layer 4, and a PBI between the core tube 3 and the outermost layer 4.
A heat roll having a PBI layer 2 containing an internal filler and / or a binder resin material in addition to the PBI layer 2 and a high molecular fluorine compound and / or a low molecular fluorine compound. The heat transfer coefficient of PBI is 0.41 W / m · K, which is smaller than the heat transfer coefficient of PTFE (for example, PBI used in the following comparative example).
In the case of TFE, it is 0.78 W / m · K). As a result, since PBI has excellent heat insulating properties, it is possible to stabilize the surface temperature of the hot roll by using it as an intermediate layer of the hot roll, so that a uniform copied image can be obtained even in high-speed copying.

FIG. 4 shows a PBI layer 2 containing an internal filler or / and a binder resin material in addition to PBI and a high molecular weight fluorine compound and / or a low molecular weight fluorine compound in a core tube 3 made of aluminum. And a hot roll having one or more intermediate layers 5. The provision of the intermediate layer 5 may improve the adhesion between the core tube 3 and the layer 2 containing PBI. The material of the mid layer 5 is, for example, PTFE
And silicone rubber. The surface PBI-containing layer 2 is used to impart abrasion resistance to the roll surface.

A pair of rolls used in a conventional toner fixing device has a layered structure shown in FIGS. That is, the core tube 3 made of aluminum is provided with the silicone rubber layer 6 or the PTFE layer 7 on the surface thereof (FIGS. 5 and 6), or the core tube 3 made of aluminum is provided with the silicone rubber layer 6 and the PTFE layer 7 on the surface thereof. Are sequentially laminated (FIG. 7). Similar to the heat roll, the heat resistance and wear resistance of the counter roll are required. However, in the toner fixing device of the present invention, in addition to the above PBI and the high molecular weight fluorine compound and / or the low molecular weight fluorine compound,
PBI containing internal filler and / or binder resin material
A hot roll with layer 2 can also be used in combination with such a conventional counter roll.

In the present invention, PBI is used as a counter roll.
In addition to and a high molecular fluorine compound and / or a low molecular fluorine compound, a compound containing an internal filler and / or a binder resin substance can also be used. That is, the counter roll of the present invention may use a sintered body of a mixture of PBI and a high molecular weight fluorine compound or / and a low molecular weight fluorine compound alone, or in addition to or together with an internal filler or /
And a binder resin material. As shown in FIG. 8, the pair of rolls of the present invention is a core tube 3 made of aluminum.
May have a PBI layer 2 containing an internal filler or / and a binder resin material in addition to the PBI and the high molecular weight fluorine compound and / or low molecular weight fluorine compound.
Further, as shown in FIG. 9, the paired roll of the present invention comprises, in addition to PBI and a high molecular weight fluorine compound or / and low molecular weight fluorine compound, an internal filler or / and / or a binder resin substance in a core tube 3 made of aluminum. It may have a PBI layer 2 to be contained and further have one or more intermediate layers 5. As a material of the mid layer 5, for example, PTFE and silicone rubber are used. The counter roll of the present invention is a conventional PBI
Can be used in combination with a heat roll having no layer containing PBI, or can be used in combination with a heat roll having a layer containing PBI described above. In view of increasing the toner fixing temperature, increasing the copying speed of electrophotographic copying machines and printers, and prolonging continuous copying, in the present invention, both the hot roll and the paired roll are made of PBI.
It is preferable to have a PBI layer containing an internal filler and / or a binder resin material in addition to the polymer fluorine compound and / or the low molecular fluorine compound.

The heat roll and the pair of rolls used in the toner fixing device of the present invention are prepared by dissolving PBI in a solvent, adding a high molecular weight fluorine compound and / or a low molecular weight fluorine compound, and homogenizing the resultant. It can be manufactured by coating tubes. That is, PBI and a solution in which a high molecular weight fluorine compound or a low molecular weight fluorine compound is dissolved in a solvent is dipped into a core tube, or PBI is applied to the surface of the core tube by electrostatic coating, and then the solvent is dried. Thereby, a target heat roll and a paired roll can be obtained. N, N
Selected from solvents commonly used in the production of dry spinning solutions of PBI, including -dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide and N-methyl-2-pyrrolidone. Particularly preferred solvents are N, N-dimethylacetamide, N-
Methyl-2-pyrrolidone.

The heat roll and the pair of rolls used in the toner fixing device of the present invention may be formed by sintering a mixture of PBI and a high molecular weight fluorine compound and / or a low molecular weight fluorine compound into a cylindrical shape or by sintering. It can also be manufactured later by processing into a cylindrical shape. Although PBI is a thermoplastic resin as described above, it cannot be melt-extruded because its melting point is higher than its decomposition point. Therefore, in order to manufacture a compact, a compact made of PBI or the like is sintered to obtain a compact.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[0025]

Example 1 Poly-2,2 '-(m
-Phenylene) -5,5'-bibenzimidazole was dissolved in 80 parts by weight of N, N-dimethylacetamide.
30% by weight of Hostaflo based on PBI in solution
n TF9205 was added, and the mixture was uniformly stirred with a homogenized mixer to obtain a coating liquid. This coating liquid was applied to the surface of a 20 mm diameter tube made of aluminum by dipping. Next, the coating was baked at 320 ° C. to obtain a PBI coating having a thickness of 20 μm.

The thus obtained PBI-coated aluminum tube is used for a Casio Electronics printer Pagepres.
t98 CP-2100 was mounted as a heat roll of a toner fixing device, and a toner fixing test on paper was performed.

As a result, during the continuous paper passing test of 200,000 sheets,
There was no one-time paper jam, and no damage was observed on the roll surface. On the other hand, when the dynamic friction coefficient of the roll surface was measured, μ = 0.07, which was equivalent to that of the PTFE alone, and was found to be excellent in mold release properties.

Further, when the roll surface temperature was raised to 260 ° C., no offset of the toner to the roll and no thermal decomposition of PBI were observed. This is because the PTFE roll is 2
In contrast to the offset occurring at 20 ° C. and the thermal decomposition of PTFE was observed.

[0029]

Example 2 The same PBI solution as in Example 1 was prepared.
30% by weight of Hostaflo based on PBI in solution
n TF1700 was added, and the mixture was uniformly stirred with a homogenized mixer to obtain a coating liquid. This coating solution was applied to the same tube surface as in Example 1 by dipping.
Next, the coating was baked at 320 ° C. to obtain a PBI coating having a thickness of 20 μm.

The thus obtained PBI-coated aluminum tube was mounted as a heat roll of the same toner fixing device as in Example 1, and a toner fixing test on paper was performed.

As a result, during the continuous paper passing test of 200,000 sheets,
There was no one-time paper jam, and no damage was observed on the roll surface. On the other hand, when the dynamic friction coefficient of the roll surface was measured, μ = 0.08, which was equivalent to that of the copolymerized fluororesin, and was found to be excellent in releasability.

Further, when the roll surface temperature was raised to 260 ° C., no offset of the toner to the roll and no thermal decomposition of PBI were observed. This was in contrast to the fact that offset occurred at 220 ° C. in the copolymerized fluororesin roll, and thermal decomposition of the fluororesin was observed.

[0033]

Example 3 The same PBI solution as in Example 1 was prepared.
30% by weight Fluowet based on PBI in solution
EA800 was added, and the mixture was uniformly stirred with a homogenized mixer to obtain a coating liquid. Fluowet EA800
Is RCH ₂ CH ₂ OH (about 95% of R is C ₈ F ₁₇
Is a fluorinated alcohol represented by This coating solution was applied to the same tube surface as in Example 1 by dipping. Next, the coating was baked at 200 ° C. to obtain a PBI coating having a thickness of 20 μm.

The PBI-coated aluminum tube thus obtained was mounted as a heat roll of the same toner fixing device as in Example 1, and a toner fixing test on paper was performed.

As a result, during the continuous paper passing test of 200,000 sheets,
There was no one-time paper jam, and no damage was observed on the roll surface. On the other hand, when the dynamic friction coefficient of the roll surface was measured, μ = 0.07, which was equivalent to that of the PTFE alone, and was found to be excellent in mold release properties.

Further, when the roll surface temperature was raised to 260 ° C., no offset of the toner to the roll and no thermal decomposition of PBI were observed. This was in contrast to the fact that offset occurred at 220 ° C. in the copolymerized fluororesin roll, and thermal decomposition of the fluororesin was observed.

[0037]

Example 4 The same PBI solution as in Example 1 was prepared.
15% by weight Hostaflo based on PBI in solution
n TF9205 and 15% by weight of Hostaflon
TF1700 was added, and the mixture was uniformly stirred with a homogenized mixer to obtain a coating liquid. This coating solution was applied to the same tube surface as in Example 1 by dipping. Next, the coating was baked at 320 ° C. to obtain a PBI coating having a thickness of 20 μm.

The PBI-coated aluminum tube thus obtained was mounted as a heat roll of the same toner fixing device as in Example 1, and a toner fixing test on paper was performed.

As a result, during the continuous paper passing test of 200,000 sheets,
There was no one-time paper jam, and no damage was observed on the roll surface. On the other hand, when the dynamic friction coefficient of the roll surface was measured, μ = 0.07, which was equivalent to that of the PTFE alone, and was found to be excellent in mold release properties.

Further, when the roll surface temperature was raised to 260 ° C., no offset of the toner to the roll and no thermal decomposition of PBI were observed. This is because the PTFE roll is 2
In contrast to the offset occurring at 20 ° C. and the thermal decomposition of PTFE was observed.

[0041]

Comparative Example 1 A continuous paper-passing test of 100,000 sheets was carried out using the same fixing device of a Casio electronic printer as in Example 1. The roll of this fixing device is made of P
It was coated with TFE + PFA (perfluoroalcohol) + graphite. As a result of the test, abrasion was observed on the roll surface after passing 50,000 sheets.

[0042]

Comparative Example 2 Poly-2,2 '-(m
-Phenylene) -5,5'-bibenzimidazole was dissolved in 80 parts by weight of N, N-dimethylacetamide and uniformly stirred with a homogenized mixer to obtain a coating liquid. This coating solution was applied to the same tube surface as in Example 1 by dipping. The coating was baked at 320 ° C. to obtain a PBI coating having a thickness of 20 μm.

The thus obtained PBI-coated aluminum tube was mounted as a heat roll of the same toner fixing device as in Example 1, and a toner fixing test on paper was performed.

As a result, during the continuous paper passing test of 100,000 sheets,
There was no one-time paper jam, but after 100,000 sheets were passed, a paper jam occurred 12 times during a continuous paper feed test up to 200,000 sheets. No damage was observed on the roll surface. On the other hand, when the dynamic friction coefficient of the roll surface was measured, it was μ = 0.27.

Further, when the roll surface temperature was raised to 260 ° C., no offset of the toner to the roll and no thermal decomposition of PBI were observed. This was in contrast to the fact that offset occurred at 220 ° C. in the copolymerized fluororesin roll, and thermal decomposition of the fluororesin was observed.

[0046]

As described above, the toner fixing device of the present invention can set the toner fixing temperature to a higher temperature, so that the copying speed can be increased. Also, because of its excellent heat insulating properties, there is little variation in the toner fixing temperature,
Power consumption required for temperature control can be reduced.
Further, since it has excellent mutual wear performance with respect to metals, plastics, paper, toner, and the like, the surface wear of the roll is small, and the life of the toner fixing device can be extended. Moreover,
Because of excellent releasability from copying paper, continuous paper passing for a long time can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a heat roll made of PBI and a high molecular weight fluorine compound or / and a low molecular weight fluorine compound.

FIG. 2 is a cross-sectional view of a heat roll having a layer containing PBI on the surface of a core tube.

FIG. 3 is a cross-sectional view of a heat roll having a layer containing PBI between a core tube and an outermost layer.

FIG. 4 is a cross-sectional view of a heat roll having an intermediate layer between a core tube and a layer containing PBI.

FIG. 5 is a cross-sectional view of a conventional paired roll in which silicone rubber is provided on the surface of a core tube.

FIG. 6 is a cross-sectional view of a conventional paired roll in which PTFE is provided on the surface of a core tube.

FIG. 7 is a cross-sectional view of a conventional paired roll in which silicone rubber and PTFE are sequentially laminated on the surface of a core tube.

FIG. 8 is a cross-sectional view of a pair of rolls having a PBI-containing layer on the surface of a core tube.

FIG. 9 is a cross-sectional view of a pair of rolls having an intermediate layer between a core tube and a layer containing PBI.

[Explanation of symbols]

 Reference Signs List 1 heat source 2 layer containing PBI 3 core tube 4 outermost layer 5 middle layer 6 silicone rubber layer 7 PTFE layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-295254 (JP, A) JP-A-2-153943 (JP, A) JP-A-4-318582 (JP, A) 67662 (JP, U) Japanese Utility Model Hei 4-57865 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (2)

(57) [Claims] 1. Poly-2,2 '-(m-phenylene)-
A toner fixing device for an electrophotographic copying machine and a printer having a thermo roll or / and a counter roll having a layer containing 5,5'-bibenzimidazole, wherein the layer is a high molecular fluorine compound and a low molecular fluorine compound 1 selected from
The above device comprising the above-mentioned fluorine compound (except that the one or more fluorine compounds consist only of polytetrafluoroethylene). 2. The low-molecular fluorine compound has 20 carbon atoms.
2. The apparatus according to claim 1, wherein the number of the fluorine-containing compounds is up to the number.