JPH0980954A - Electrophotographic image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deposition of a paper powder or dirt produced from recycled paper and to prevent production of image defects by using a fluorinated silicone oil having a specified structural unit as a release agent to be applied on a fixing member. SOLUTION: In this image forming method, a recycled paper recording material in which deinked waste paper pulp is used by >=20% is used. The recycled paper recording material carrying a toner image comprising a resin and a coloring agent is passed between a fixing member which moves and a pressing member which rotates and presses the fixing member so that the toner image is thermally fixed by a heating member which is fixed in the device. A fluorinated silicone oil having a structural unit expressed by a formula is applied on the fixing member. In the formula, X is a hydrocarbon group or aryl group having 1-4 carbon number, Rf is a fluoroalkyl group of 2-10 carbon number and (n) is an integer 1 to 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming method, and more particularly to an electrophotographic image forming method which is stable over a long period of time even when recycled paper is used and does not cause image defects.

[0002]

2. Description of the Related Art Conventionally, paper has been generally used as a transfer material in electrophotography. Regarding paper, so-called recycled paper, which is deinked and recycled after use, has been used from the viewpoint of environmental protection. However, there are cases where various kinds of impurities are present in the recycled paper, and for example, Japanese Patent Laid-Open No. 5-10
Transfer paper in which used paper pulp is used for 0465 and the amount of foreign substances is regulated, and in JP-A-4-147152 is used transfer paper in which deinked waste paper pulp is used and an abrasive is used as a filler. No. 287894 uses recycled paper recycled paper to define the equilibrium moisture content, and Japanese Laid-Open Patent Publication No. 4-65596 uses used pulp to transfer chemical pulp in a specific range with a specific moisture range. No. 6-35221 shows that the problem can be solved even when used in electrophotography by controlling the constitution of recycled paper, such as transfer paper in which residual ink is less than a specific range in recycled pulp. Has been done.

However, since the recycled paper treated with these various processes becomes complicated, it becomes expensive and the versatility is lowered.

Therefore, there is a demand for an image forming method which does not cause a problem even when general recycled paper is used.

A problem that occurs when so-called recycled paper is used is that various contaminants present in the recycled paper are detached from the transfer paper, and fixing is performed in a contact type fixing system such as heat roll fixing. There is a problem that it adheres to the part and scratches.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic image forming method in which no paper dust or contaminants generated from recycled paper adhere to a fixing device and stable image defects do not occur for a long period of time. To provide.

[0007]

The above object of the present invention has been achieved by the following constitution.

(1). Between the moving fixing member coated with the release agent and the pressing member that is pressed against the fixing member and rotates.
At least 20% or more of deinked waste paper pulp carrying a toner image composed of at least a resin and a colorant is passed through a recycled paper recording material, and the toner image is reproduced through the fixing member by a fixedly arranged heating member. An electrophotographic image forming method of thermally fixing to a paper recording material, wherein the releasing agent is a fluorine-containing silicone oil having a structural unit represented by the following general formula.

[0009]

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[In the formula, X represents a saturated hydrocarbon group having 1 to 4 carbon atoms or is an aryl group, Rf represents a fluoroalkyl group having 2 to 10 carbon atoms, and n represents an integer of 1 to 4. (2). The electrophotographic image forming method according to (1), wherein the fixing member is a fixing roller including the heating member.

(3). The electrophotographic image forming method according to (1), wherein the fixing member is a film-shaped member.

That is, according to the present invention, the fluorine-containing silicon oil has good wettability to the fixing device and can be applied uniformly. Therefore, the adhesiveness to the fixing device itself becomes low. Since the paper dust present in the recycled paper has undergone the recycling process, it is more likely to be released than the paper itself. For this reason, there arises a problem that the toner is electrostatically attached to the fixing device. This adhesion can be prevented by using silicon oil having high wettability to the fixing device.

On the other hand, recycled paper is used as a raw material for paper after deinking printed matter and removing ink and the like. However, it is not practical to completely remove the ink or the like because the cost becomes high. Therefore, various printing materials, that is, ink, remains in the recycled paper. There are various types of ink, and the phenomenon of adhesion of these is effective for preventing the occurrence of scratches in the fixing device. By using the silicone oil of the present invention having high wettability, it is possible to prevent the adhesion of foreign substances present in recycled paper, and it is possible to improve the durability. is there.

The present invention will be described in detail below.

<< Fluorine-Containing Silicon Oil of the Present Invention >> The fluorine-containing silicone oil of the present invention is a silicone oil having a structural unit represented by the following general formula (1).

[0016]

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Here, X represents a saturated hydrocarbon group having 1 to 4 carbon atoms or an aryl group, and Rf is a fluoroalkyl group having 2 to 10 carbon atoms, preferably Z- (CF ₂ ) _m-.
(Z represents a hydrogen atom or a fluorine atom, and m is 2 to 10
Is an integer of) is a group represented by. Further, Rf is preferably a fluoroalkyl group having 2 to 8 carbon atoms. Further, n is an integer of 1 to 4, m is an integer of 2 to 10, and m is 2 to 8.
Is preferably an integer.

The fluorine-containing silicone oil of the present invention is required to have the repeating unit described above, but even if it has a copolymer structure with dimethyl silicone, phenylmethyl silicone, diphenyl silicone, or the like. Good.
It is essential that the fluorine-containing silicone oil according to the present invention is a liquid one having an appropriate viscosity when used. Therefore, the viscosity at 25 ° C is 20 to 1000c.
It preferably has a viscosity of s, preferably 100 to 500 cs. The adjustment of the viscosity can be controlled by adjusting the degree of polymerization. This viscosity shows dynamic viscosity, AST
MD 445-46T or JIS Z8803
It is measured by a Ubbelohde viscometer.

When the fluorine-containing silicone oil of the present invention is a copolymer, it should contain 20 mol% or more of the structural unit represented by the general formula (1) of the present invention in view of the achievement of various objects of the present invention. Good. If it is less than this range, the effect of the fluorine-containing silicone oil is not exhibited, and the effect of other components is remarkably exhibited.

In the method for producing a fluorine-containing silicone oil of the present invention, similar to the ordinary method for producing a silicone oil, a dialkyl-substituted dichlorosilane is prepared by a reaction between silicon and alkyl chloride, and hydrolysis is carried out using this. To form a siloxane, and then to form a cyclic oligomer or a linear oligomer, and then polymerize these to synthesize.
The fluorinated silicone oil compound of the present invention has a fluorinated alkyl group in the side chain, but in this case, a fluorinated compound having a chloro group at the terminal instead of alkyl chloride, for example, the following general formula It is easily manufactured by using the structure shown in.

Z- (CF ₂ ) _m (CH ₂ ) _n Cl Here, m represents an integer of 2 to 10, and n represents an integer of 1 to 4. Z represents a hydrogen atom or a fluorine atom.

Specific examples include compounds having the structures shown below.

(A) CF ₃ CF ₂ CH ₂ Cl (B) CF ₃ CF ₂ CF ₂ CH ₂ Cl (C) CF ₃ CF ₂ CF ₂ (CH ₂ ) ₂ Cl (D) CF ₃ CF ₂ CF ₂ CF _{2 (CH 2) 2 Cl (} E) CF 3 CF 2 CF 2 CF 2 CF 2 CH 2 Cl (F) CF 3 CF 2 CF 2 CF 2 CF 2 (CH 2) 3 Cl (G) CF 3 CF 2 CF _{2 CF 2 CF 2 CF 2 CH} 2 Cl (H) CF 3 CF 2 CF 2 CF 2 CF 2 CF 2 CF 2 CH 2 Cl (I) HCF 2 CF 2 CH 2 Cl (J) HCF 2 CF 2 CF 2 CH _{2 Cl (K) HCF 2 CF} 2 CF 2 (CH 2) 2 Cl (L) HCF 2 CF 2 CF 2 CF 2 CH 2 Cl (M) HCF 2 CF 2 CF 2 CF 2 (CH 2) 2 Cl (N _{) HCF 2 CF 2 CF 2 CF} 2 (CH 2) 4 Cl (O) HCF 2 CF 2 CF 2 CF 2 CF 2 (C _{2) 3 Cl (P) HCF} 2 CF 2 CF 2 CF 2 CF 2 CF 2 CH 2 Cl As the alkyl chloride to introduce an alkyl group other than fluorinated alkyl group in the present invention include methyl chloride, ethyl chloride, Propyl chloride and butyl chloride can be mentioned.

In the present invention, the fluorine number has a great effect in order to exert the effect of uniform adhesion to the fixing roll coated with the fluororesin by using the silicone oil substituted with the fluoroalkyl. It is a thing.
In this case, the alkyl fluoride has 1 to 10 carbon atoms,
The portion directly bonded to the silicon atom is preferably a methylene chain. Furthermore, a suitable range is 2-8. When heat is applied when the number of fluorinated alkyl carbons becomes excessive,
The fluidity becomes so large that it becomes difficult to hold it in a bed or the like. Further, when the fluorinated alkyl is not contained, the wettability with respect to the surface of the heat roll coated with the fluororesin is not improved, and a uniform oil film cannot be formed.

Specific examples of the fluorine-containing silicone oil having the structural unit represented by the general formula (1) of the present invention are shown below, but the present invention is not limited thereto.

[0026]

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[0027]

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[0028]

[Chemical 6]

Here, a and b are integers of 1 or more, preferably 10 to 1000, and more preferably 20 to 100. Moreover, a + b is not particularly limited, but is preferably 40 to 150.

<< Developer >> The toner of the present invention is not particularly limited. The volume average particle diameter is 1 to 30 μm, preferably 5 to 20 μm. The binder resin that constitutes the toner is not particularly limited, and various conventionally known resins can be used. For example, a styrene resin, an acrylic resin, a styrene / acrylic resin, a polyester resin, and the like can be given.

The colorant constituting the toner is not particularly limited, and various conventionally known materials are used. Examples include carbon black, nigrosine dye, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, rose bengal, and the like. Examples of other additives include salicylic acid derivatives,
Examples include charge control agents such as azo metal complexes.

When a magnetic toner is obtained, the colored particles contain magnetic particles as an additive. As the magnetic particles, particles such as ferrite magnetite having an average primary particle diameter of 0.1 to 2.0 μm are used. The amount of the magnetic particles added is 20 to 70% by weight of the colored particles.

From the viewpoint of imparting fluidity, inorganic fine particles may be added. The inorganic fine particles are preferably inorganic oxide particles such as silica, titania, and alumina, and further,
These inorganic fine particles are preferably hydrophobized with a silane coupling agent, a titanium coupling agent, or the like.

The toner is mixed with a carrier and used as a two-component developer, or when it is a magnetic toner, only the magnetic toner is used as a one-component developer. As the carrier constituting the two-component developer, either an uncoated carrier composed only of magnetic material particles such as iron and ferrite, or a resin coated carrier in which the surfaces of the magnetic material particles are coated with a resin may be used. The average particle size of the carrier is preferably 30 to 150 μm in volume average particle size.

On the other hand, a release agent may be added. Examples of the releasing agent include low molecular weight polyolefins, fatty acid amides and natural waxes. The addition amount of these is preferably 1 to 5% by weight in the toner.

<Fixing Method> Suitable fixing methods used in the present invention include a heat roll fixing method and a film-like fixing method (a fixed heating member and a pressure member facing the heating member and rotating. Then, a fixing method of heating and fixing the toner image on the recording material by a pressure member that presses the recording material onto the heating body via a film material can be mentioned.

The former heat roll fixing system will be described with reference to FIG. 1. It is composed of iron or aluminum whose surface 2 is coated with, for example, tetrafluoroethylene or polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymers. The metal roller 3 is composed of an upper roller 1 having a heat source 4 inside and a lower roller 5 made of silicon rubber or the like. Specifically, the heat source 4 has a linear heater, and the surface temperature of the upper roller 1 is about 1
It is heated to about 10 to 220 ° C. The recording material 6 carrying the toner image 7 of the present invention is passed between the upper roller 1 and the lower roller 5 to heat-melt and fix the toner image 7 on the recording material. In this heat roller fixing method, it is widely practiced to apply pressure between the upper roller and the lower roller to the fixing portion to deform the lower roller and form a so-called nip. The nip width is 1 to 10 mm, preferably 1.5 to 7 mm. Fixing linear velocity is 40 ~ 500mm
/ Sec is preferable. If the nip width is narrow, heat cannot be uniformly applied to the toner, and uneven fixing tends to occur. On the other hand, when the nip width is wide, toner melting is promoted, and the offset phenomenon is likely to occur.

As the latter type of fixing system,
An example of the film-type fixing system will be described with reference to FIG. 2. A low heat capacity linear heating element 15 fixedly supported by the apparatus.
Has a thickness of 0.2 to 5.0 mm, preferably 0.5 to 3.
5 mm, width 10 to 15 mm, long length 240 to 400 mm
The alumina substrate 17 is coated with a resistance material in a thickness of 1.0 to 2.5 mm, and is energized from both ends. The energization is applied by changing the pulse width according to the temperature controlled by the temperature sensor 16 and the amount of energy released with a pulse waveform of DC 100 V and a cycle of 25 msec. The temperature T detected by the temperature sensor 16 in the low heat capacity linear heating element 15
In the case of 1, the surface temperature T2 of the film material 14 facing the resistance material is lower than the temperature T1. Where temperature T
1 is preferably 110 to 220 ° C., and the temperature of T2 is preferably 0.5 to 10 ° C. lower than the temperature of T1. The film material surface temperature T3 at the portion where the film material 14 is peeled off from the toner fixing surface is almost equal to T2. In this way, the film material moves in the same direction as the recording material by coming into contact with the heating body whose energy and temperature are controlled.
The film material 14 has a thickness of 10 to 35 μm.
m heat resistant film such as polyester, polyperfluoroalkyl vinyl ether, polyimide, polyether imide and a release material layer made by adding conductive material to at least fluororesin such as Teflon for 5 to 15 μm, and preferably endless. It is a film material. Generally, the total thickness is 10 to 100 μm, and the film material 14 is driven by the film material driving roller 11 and the film material driven roller 1.
Driven by 2 and tension, it is transported without wrinkles and twists. The fixing linear velocity is preferably 40 to 500 mm / sec. The pressure roller 13 has a rubber elastic layer having a high releasability such as silicon rubber, and the film material 14 has a total pressure of 2 to 30 kg.
The low heat capacity line-state heating body 15 is pressed through the pressurizing roller 15 and is rotated by pressure contact in the direction of the arrow, and this film material 14 and the pressure roller
The recording material carrying the toner image is passed between the recording medium 3 and the recording medium 3, and the low heat capacity linear heating element 15 is passed to melt and fix the toner image and the recording material.

Further, as the latter type of fixing system,
Another example of the film fixing method will be described with reference to FIG. The example of FIG. 3 is an example of the endless film material 24, whereas the example of FIG. 2 is the endless film material 14. That is, as shown in FIG. 3, the end film material 24 is wound around the sheet feeding shaft 21 and the winding shaft 22, and the film material 24 is gradually moved in the direction of the arrow for each fixing. In this case, the winding shaft 22 drives. 13, 15, 1
6, 17 are the same as those in FIG.

The feeding shaft 2 is driven by the winding shaft 22.
The edged film material 24 wound around 1 is ejected little by little at each fixing, and a recording material carrying a toner image is passed between the edged film material 24 and the pressure roller 13,
The toner image is melted and fixed to the recording material by passing through the low heat capacity linear heating element 15.

Further, it may be a simple cylinder having no supporting roller such as a driving roller inside.

In any case, a fixing cleaning mechanism is added and used. As this method, a method of supplying the fluorine-containing silicon oil of the present invention to the upper roller or film for fixing, or a method of cleaning with a pad, roller or web impregnated with the fluorine-containing silicon oil of the present invention can be used. .

As shown in FIGS. 1 and 2, for example, the rollers 8 and 18 are formed by using a non-woven fabric, and are rotated by the roller 1 or the film 14, which are included in the present invention. It is used by being impregnated with fluorinated silicone oil. Alternatively, in FIG. 3, the film 24 itself is impregnated with the fluorine-containing silicone oil of the present invention and wound around the shaft 21 for use.

<< Recycled Paper >> In the present invention, recycled paper refers to paper formed using so-called waste paper pulp. The recycled paper containing 20% by weight or more of recycled paper, especially 50% by weight or more of the recycled paper, exhibits the effect of the present invention remarkably. Here, used paper pulp is the top white, ruled white, cream white, card, special white, middle white, imitation, fair white, kent, white shown in the standard standard specifications for used paper at the Waste Paper Recycling Promotion Center. Examples include art, special cuts, separate cuts, newspapers, and magazines. Specifically, information-related paper such as non-coated computer paper, thermal paper, printer paper such as pressure-sensitive paper, and OA waste paper such as PPC paper, art paper, coated paper, light-coated paper, matte paper, etc. Paper or high quality paper, high quality color paper, notebook, notepaper, wrapping paper, fancy paper, medium quality paper, newsprint, waste paper, super hanging paper, imitation paper, pure white roll paper, uncoated paper such as milk carton, etc. Paper and paperboard waste paper.

These used papers are used for so-called deinked used papers, such as printing and the like, which have been used for deinking. The deinking process is as follows: disaggregation process: waste paper is treated with mechanical force and chemicals to disintegrate fibrous loosening, printing ink and ash from the fibers.

Dust removal step: Foreign substances (plastic etc.) and dust contained in used paper are removed by a screener or screen.

Deinking process: The ink separated from the fibers and dispersed is removed by a flotation method or a washing method.

And the like.

Further, as the pulp used for constituting the paper, pulp obtained from hardwood and pulp obtained from softwood are used, but pulp obtained from hardwood is preferable.

Examples of the sizing agent added to the paper include alkenyl succinic anhydride, alkyl ketene dimer, fatty acid anhydride, and isocyanate aziridine derivative.

As the physical properties of paper, the surface resistance is 22 ° C./6.
It is preferably set to 1 × 10 ⁹ to 1 × 10 ¹² Ω after standing in a 5% environment (JIS-C-211). The smoothness is preferably 21 seconds or more on the surface (wire surface) (JI
SP-8119). The amount of water present in the paper is preferably adjusted to 4.0 to 6.0% in order to reduce the influence of curling (JIS-P-8125). Further, the whiteness is preferably 80 to 90% (JIS-P-8.
123).

The filler is not particularly limited, but calcium carbonate is preferably used from the viewpoint of storability.

[0053]

【Example】

 << Paper Production Example 1 >> Paper was prepared with the formulations shown in the following table.

[0054]

[Table 1]

<< Developer Manufacturing Example >> Polyester resin (PE
s) 100 parts, 5 parts of carbon black and 3 parts of low molecular weight polypropylene were added, and the mixture was melted and kneaded, pulverized and classified to obtain colored particles having a volume average particle diameter of 8.3 μm. Then, 0.8% of hydrophobic silica was added to this product to obtain a toner.

A styrene-acrylic resin-coated ferrite carrier having a volume average particle size of 62 μm was mixed with these toners to prepare a developer having a toner concentration of 7% by weight.

<< Evaluation Method >> A copying machine 3035 manufactured by Konica Corporation was modified and used as an evaluation machine. Below are the details of the modification related to the fixing conditions.

The above evaluation paper was used after being adjusted to A4 size.

Heat Roll Fixing Condition The heat roll fixing device shown in FIG. 1 is used as a fixing device.
The upper roller is a cylindrical iron having a 30 mm diameter heater whose surface is coated with a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer in the central portion, and the surface is similarly tetrafluoroethylene-perfluoroalkyl ether copolymer. It has a lower roller of 30 mm in diameter made of silicone rubber coated with a polymer.
The linear pressure is set to 0.8 kg / cm, and the width of the nip is 4.
3 mm. Use this fixing machine to increase the printing linear velocity to 2
It was set to 50 mm / sec. A roller impregnated with a fluorine-containing silicone oil as a release agent was attached and used as a cleaning mechanism of the fixing device. Fluorine-containing silicone oil exemplified compounds (3), (7) of the present invention,
Using (8) and (13), these heat roll fixing conditions are R-1, R-2, R-3, and R-4, respectively.

The surface temperature of the fixing device was 180 ° C.

Film-like fixing conditions The endless film-like (sheet) type fixing device shown in FIG. 2 was used as the fixing device, and the fixing conditions were set as follows.

Fixing condition: heating body temperature T1 = 180 ° C .: film material speed = 250 mm / sec: total pressure between heating body and pressure roll = 15 kg: nip between pressure roller and film material = 3 mm: film material: on surface A polyimide film material having a thickness of 15 μm and coated with polytetrafluoroethylene in which a conductive substance is dispersed was used by mounting a pad impregnated with fluorine-containing silicone oil as a releasing agent as a cleaning mechanism of the fixing device. Using the fluorine-containing silicone oil exemplified compounds (3), (7), (8) and (13) of the present invention, these film-like fixing conditions were respectively F-1, F-2 and F-.
3 and F-4.

Fixing Condition for Comparison On the other hand, as a fixing device for comparison, a silicone oil composed of dimethylpolysiloxane (dimethylsilicone oil) was used as a releasing agent in the above-mentioned device, and Japanese Patent Application Laid-Open No. S52-52:
A fluorine-based silicone oil (FS-1265: manufactured by Dow Corning Co., Ltd.) in which the alkyl fluoride of the side chain described in No. -124338 is simply trifluoromethyl was used. When dimethyl silicone oil was used, the heat roll fixing device and fixing conditions were set to R-ratio 1, and the film-like fixing device and fixing conditions were set to F-ratio 1. When fluorine-based silicone oil was used, the fixing conditions were the same. The R-ratio is 2 and the F-ratio is 2, respectively.

<Evaluation> An image having a pixel ratio of 2% was formed in a low temperature and low humidity environment (10 ° C., 20% RH) using the above developer and transfer paper.
After printing 50,000 sheets, the presence or absence of scratches on the fixing roller or the film was judged. Tables 2 and 3 show the results of visual judgment for the presence of scratches.

[0065]

[Table 2]

[0066]

[Table 3]

As is clear from Tables 2 and 3, when the fluorine-containing silicone oil of the present invention is used, scratches do not occur at the fixing portion even when recycled paper is used, and a stable image is formed. be able to.

[0068]

According to the present invention, it is possible to provide an electrophotographic image forming method in which no paper dust or contaminants generated from recycled paper adhere to a fixing device and stable image defects do not occur for a long period of time. It was

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a heat roller fixing system.

FIG. 2 is a schematic view showing an example of a film fixing system.

FIG. 3 is a schematic view showing another example of a film-like fixing system.

[Explanation of symbols]

 1 Upper roller 4 Heat source 5 Lower roller 6 Recording material 11 Film material driving roller 12 Film material driven roller 14 Film material 15 Low heat capacity linear heating element

Claims (3)

[Claims] 1. A deinked waste paper carrying a toner image comprising at least a resin and a colorant between a moving fixing member coated with a releasing agent and a pressure member rotating in pressure contact with the fixing member. In an electrophotographic image forming method, a recycled paper recording material containing at least 20% of pulp is passed through, and a toner image is heat-fixed to the recycled paper recording material via the fixing member by a heating member fixedly arranged. An electrophotographic image forming method, wherein the release agent is a fluorine-containing silicone oil having a structural unit represented by the following general formula. Embedded image [In the formula, X represents a saturated hydrocarbon group having 1 to 4 carbon atoms or an aryl group, Rf represents a fluoroalkyl group having 2 to 10 carbon atoms, and n represents an integer of 1 to 4. ] 2. The electrophotographic image forming method according to claim 1, wherein the fixing member is a fixing roller having the heating member built therein. 3. The electrophotographic image forming method according to claim 1, wherein the fixing member is a film-shaped member.