JPH0916011A - Image forming method and image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device which is good in the adhesiveness of modified silicone oil supplied to the surface of a heating roller and is capable of preventing the adhesion of toners and shortening the warming up time of the device and an image footing method using this device. CONSTITUTION: This image forming method has a stage for forming electrostatic latent images on an image carrying member 11, a stage for developing the electrostatic latent images by using the developer on a developer carrying member 4, a stage for transferring the toner images formed on the image carrying member onto a transfer body 6 and a fixing stage for heating and fixing the toner images onto this transfer body 6. A developer contg. the toner compsn. formed by using a binder resin essentially consisting of a polyester resin having 10 to 40wt.% tetrahydrofuran insoluble component is used as the developer. The fixing is executed in the fixing stage by using the device which is provided with the heating roller 11 which has a smooth surface coated with a layer of metal oxide and is provided with a heating source and a press roller 12 so as the face each other and has a means for applying the modified silicone oil on the surface of the heating roller 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for forming an image by developing an electrostatic latent image in electrophotography, electrostatic recording, etc., and an image forming apparatus used therefor.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system such as an electronic copying machine or a laser printer, a toner image formed on an image bearing member such as a photosensitive drum is transferred onto a sheet and fixed by a fixing device to copy the image. The one that adopts the method of manufacturing is used. As the fixing device, a heating roller type device is generally used, and the heating roller type fixing device is composed of a heating roller having a heating source inside and a pressure roller, and the heating roller. And a mechanism for setting a large nip pressure between both rollers.

Since the surface of the heating roller is in direct contact with the toner image bearing surface of the paper, it is required to provide means for preventing the molten toner from adhering to the surface of the heating roller. Therefore, in the conventional fixing device, for example, as shown in JP-A-61-205968, a fluororesin film is formed on the surface of the heating roller, and a silicone is applied to the surface of the heating roller. A means for applying oil or the like is provided to prevent the melted toner from adhering to the surface of the heating roller. Further, in the pressure roller arranged to face the heating roller, a metal core whose surface is covered with a relatively thick elastic body is used.

In this fixing device, the heating roller is driven in accordance with the sheet conveying speed, the photosensitive drum rotation speed, or the like, so that the pressure roller is rotated by the contact of both rollers, and both rollers are rotated. The toner image of the sheet nipped between the sheets is melted and pressed against the sheet so that the fixing action is exhibited. When the toner is melted, the surface of the heating roller is coated with a fluororesin, and since the silicone oil or the like is applied, it is difficult for the toner to adhere. Prevents the copy from becoming dirty without sticking to the surface of the heating roller.

Further, in the fixing device, there is a problem that the sheet is adhered to the heating roller and the pressure roller because the sheet is pressed between both rollers and is bent. Therefore, in the conventional fixing device, in order to peel the paper from the roller, a peeling claw is arranged for each of the rollers, and a mechanism for peeling the leading end of the paper using the peeling claw means is provided. Then, the state in which the paper is wound around the roller is generated by using the means for constantly contacting the peeling claw with the roller, the mechanism for contacting the claw member with the roller surface only when peeling the leading end of the paper, and the like. I try to prevent it.

[0006]

However, in the conventional fixing device as described above, when the surface of the heating roller is covered with the fluororesin and the peeling claw comes into contact with the portion for peeling the paper from the roller, This causes a problem of scratching the surface of the heating roller. If the surface of the heating roller is scratched, streaky stains may occur on the copy, or defective fixing may occur. Also,
Even when the surface of the heating roller is coated with fluororesin, a thin elastic layer is often provided on the surface of the roller core.When such a coating is constructed, the thermal conductivity of the coating layer is poor and heating is difficult. It takes a lot of time for the heat of the heat source to reach the surface of the roller, and there is a problem that the waiting time (warming-up time) from when the device is turned on to when the fixing device is ready for use becomes longer. .

Therefore, in order to shorten the waiting time,
As disclosed in JP-A-61-73980,
It has been proposed that a heating roller is composed of a ceramic core, a layer of a heating element is formed on the surface of the core, and the surface of the heating element is covered with a thin fluororesin. The heating roller as described above has an effect of raising the temperature to a temperature at which the fixing operation can be performed in a very short waiting time after the energization of the fixing device is started. However, the ceramic roller member has a problem that it takes a lot of time and effort to manufacture because the ceramic is formed into a cylindrical shape and is fired at a high temperature, and it is difficult to process it after firing. ing.

In addition to the above-mentioned problems, even when the surface of the heating roller is coated with fluororesin and silicone oil is applied, the melted toner tends to adhere to the surface of the roller in a state of pushing the oil away. However, even a fluororesin having a relatively good releasability cannot completely prevent the toner from adhering. Further, in order to prevent the coating on the surface of the heating roller from being damaged by the peeling claw, a mechanism for retracting the peeling claw member is provided,
Means such as providing a mechanism in which the claw contacts the heating roller only when the leading edge of the paper is peeled off is also used, but the above-mentioned problem cannot be completely solved under the present circumstances. Further, when a toner for low temperature fixing is used, there is a problem that offset is likely to occur and the long-term durability is poor.

The present invention has been made for the purpose of solving the above-mentioned problems. That is, an object of the present invention is to provide an image forming apparatus which has good adhesion of the modified silicone oil supplied to the surface of the heating roller, prevents toner from adhering, and can shorten the warm-up time of the apparatus. Another object of the present invention is to have an extremely wide feasible temperature range, that is, a wide range of the minimum fixing temperature for obtaining a satisfactory degree of fixing and the maximum temperature at which hot offset does not occur. An object of the present invention is to provide an image forming method using a toner that does not cause a problem of offset.

[0010]

According to the image forming method of the present invention, a step of forming an electrostatic latent image on an image bearing member, the electrostatic latent image is developed using a developer on the developer bearing member. The method comprises a step, a step of transferring the toner image formed on the image bearing member onto a transfer body, and a fixing step of heating and fixing the toner image on the transfer body. A toner composition containing a binder resin containing 40% by weight of a polyester resin as a main component is used, and in the fixing step, the toner composition has a smooth surface covered with a metal oxide layer, It is characterized in that a heating roller provided with a heating source and a pressure roller are provided so as to face each other, and fixing is carried out using an apparatus having a means for applying the modified silicone oil to the surface of the heating roll.

The image forming apparatus of the present invention comprises a latent image forming means for forming an electrostatic latent image on an image carrier, a developing means for developing the electrostatic latent image with a developer on the developer carrier, It has a transfer means for transferring the toner image formed on the image carrier onto the transfer body and a fixing means for heating and fixing the toner image on the transfer body, and the tetrahydrofuran-insoluble matter is 10 to 4 as a developer.
To use a toner composition containing a binder resin containing 0% by weight of a polyester resin as a main component, wherein the fixing means is a smooth surface coated with a metal oxide layer. An apparatus having a heating roller provided with a heating source and a pressure roller facing each other, and having a means for applying the modified silicone oil to the surface of the heating roll.

The present invention will be described in detail below. The binder resin in the toner composition used in the present invention contains a polyester resin as a main component, and as the polyester resin, a polyvalent hydroxy compound and a polyvalent carboxylic acid or a lower alkyl ester thereof, an acid-free water is used. And a reactive acid derivative such as an acid halide are used. As the polyhydroxy compound,
Ethylene glycol, propylene glycol, 1,4-
Butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, polyethylene glycol such as triethylene glycol, dipropylene glycol ,
In addition to polypropylene glycols such as tripropylene glycol, bisphenol A and its derivatives, alkylene oxide adducts thereof, divalent hydroxy compounds such as hydrogenated bisphenol A, glycerin, sorbitol, 1,4-sorbitan, trimethylolpropane and the like. A hydroxy compound having a valency or higher can be used.

Examples of the polyvalent carboxylic acid include malonic acid, succinic acid, glutaric acid, 1,2,5-hexanetricarboxylic acid, 1,2,7,8-octanetetracarboxylic acid and n-octylsuccinic acid. , 1,3-dicarboxy-2-methyl-2-carboxymethylpropane, tetra (carboxymethyl) methane, maleic acid, fumaric acid,
Dodecenyl succinic acid, 1,2,4-cyclohexanetricarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid,
Trimellitic acid, pyromellitic acid, and 1,2,4-naphthalenetricarboxylic acid can be used.

The polyester resin used in the present invention has a weight average molecular weight Mw of 7,000 to 50,000, a number average molecular weight Mn of 2,000 to 10,000, and T
The g is preferably in the range of 50 to 70 ° C. The polyester resin has a tetrahydrofuran (THF) insoluble content of 10% by weight to 40% by weight, preferably 10% by weight to 25% by weight.
Are used. 10% by weight of THF insoluble matter
If it is less than 40% by weight, the offset resistance is poor, and if it exceeds 40% by weight, the pulverizability of the toner is poor.

In the present invention, the toner composition contains a colorant, and any known colorant can be used as the colorant. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I.
I. Pigment Yellow 12, C.I. I. Pigment
Yellow 17, C.I. I. Pigment Yellow 97,
C. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 3 can be mentioned as a typical example. In general, these colorants may be contained in the toner composition in the range of 2 to 50% by weight.

When the toner composition of the present invention is used as a magnetic toner, a part or all of the colorant can be replaced with magnetic powder. As the magnetic powder, known magnetic materials, for example, metals such as iron, cobalt, nickel and alloys thereof, Fe ₃ O ₄ , γ-Fe ₂ O ₃ , metal oxides such as cobalt-added iron oxide, MnZn ferrite, Magnetite, hematite and the like can be used, and those treated with a silane coupling agent or a titanium coupling agent can also be used.

Various substances can be added to the toner composition used in the present invention for the purpose of charge control, electric resistance control and the like. For example, a fluorine-based surfactant,
Chromium dyes such as salicylic acid and chromium complexes, charge controlling resins such as maleic acid and copolymers containing amino group-containing vinyl monomers as monomer components, quaternary ammonium salts, azine dyes such as nigrosine, etc. Can be added. Furthermore, a releasing agent may be added in order to make offset resistance more complete, and polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene, paraffin wax, candelilla wax, carnauba wax, montan wax, etc. Natural wax and its derivatives can be used.

In the present invention, an external additive may be added to the toner composition. The external additive used is Si
O ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO
₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO,
K ₂ O, Na ₂ O, ZrO ₂ , CaO · SiO ₂ , K ₂
O · (TiO ₂ ) _n , Al ₂ O, 2SiO ₂ , CaCO
Examples thereof include fine particles of inorganic compounds such as ₃ , MgCO ₃ , BaSO ₄ , and MgSO ₄ , and those whose surface is treated with a resin or various coupling agents. In particular, SiO ₂ is excellent in order to improve fluidity and cohesiveness, and those having a particle size of 16 nm or less are particularly preferable. Further, in order to improve the offset property, metal oxide fine particles treated with silicone oil, particularly silica, are preferable. The amount of these external additives added to the toner composition is preferably 0.
It is from 05% by weight to 2.5% by weight, more preferably from 0.2% by weight to 1.0% by weight. Particularly preferably 0.3% by weight
~ 0.8% by weight. When the amount of the external additive added is less than 0.05% by weight, the effect of offset resistance is small, and when it is more than 2.5% by weight, problems such as filming on the image carrier occur.

In the present invention, the above-mentioned toner composition is used, and in the fixing step, a heating roller having a smooth surface coated with a metal oxide layer and provided with a heating source, and a pressure roller are used. The image forming apparatus of the present invention having such a fixing device will be described because fixing is performed by using a device provided with a roller facing each other and having means for applying modified silicone oil to the surface of the heating roll. . FIG. 1 is a schematic configuration diagram of an image forming apparatus of the present invention. In the image forming apparatus of the present invention, latent image forming means for forming an electrostatic latent image on the image carrier 1 by, for example, the corona charger 2 and the image exposure device 3, and developing the electrostatic latent image on the developer carrier 4. A developing means for developing using the agent 5, a transfer means 7 for transferring the toner image formed on the image carrier 1 onto the transfer body 6, and a fixing means for heating and fixing the toner image on the transfer body, The fixing means has a smooth surface coated with a metal oxide layer, and a heating roller 11 and a pressure roller 12 provided with a heating source inside are provided to face each other, and the surface of the heating roll is modified. The fixing device 10 has means for applying silicone oil. Incidentally, 8 is a cleaning means.

Further, in the present invention, in the heating roller, the aluminum oxide layer is formed on the surface of the aluminum core, and the concave portion formed in the aluminum oxide layer is filled with a filling material such as molybdenum sulfide. It is possible to use a heating roller having a smooth surface.

[0021]

According to the present invention, when the image forming apparatus having the above-mentioned structure is used and the image forming method is adopted, the conventional apparatus having the fixing device using the heating roller whose surface is coated with resin is used. The drawbacks of are eliminated. That is,
Since the surface of the heating roller is not covered with resin, the heat from the heat source inside the roller reaches the surface immediately, and the time for heating the heating roller surface to a certain temperature is shortened, and the waiting time required for warming up Makes it possible to shorten. Further, in the present invention, since a very hard metal oxide layer is formed on the surface of the heating roller, even if the peeling claw is always in contact with the surface, the surface is not scratched, and the copy is soiled by scratches on the roller surface. It has the effect of preventing the problem of swelling. Furthermore, since the metal oxide layer has an excellent property of retaining the modified silicone oil, it is possible to prevent the molten toner from pushing away the silicone oil and adhering to the surface of the heating roller, thereby contaminating the surface of the heating roller. Shows the action of preventing.

Further, in the present invention, since the polyester resin containing 10% by weight to 40% by weight of THF insoluble matter is used in the toner composition, the binder resin has excellent low-temperature fixability, and the warm-up time is increased. Since the toner can be further shortened and has excellent offset properties as a toner, even if the viscosity increases due to thermal deterioration of the silicone oil and the releasability decreases after long-term use, contamination of the heating roll surface can be prevented.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows the structure of an embodiment of a fixing device used in the image forming apparatus of the present invention. As in the case of the conventional heating roller type device, the fixing device 10 is configured by disposing a heating roller 11 accommodating a heating source 13 such as a halogen lamp and a pressure roller 12 so as to face each other. Of the two fixing roller members, the pressure roller 12 is a metal core member whose surface is covered with an elastic member with a thickness of several mm. It is provided so as to press with a predetermined nip pressure. Also, for the two fixing rollers,
A peeling claw 14 for peeling the sheet is arranged to perform an action of peeling the sheet on which the fixing is completed. In the fixing device, the heating roller 11 has a surface coating 16 of metal oxide formed on the surface of a metal roller core 15. The roller core 15 is a pipe-shaped member having a size of several millimeters, and the surface thereof is covered with a material. The surface coating 16 is provided with a thickness of μm to several tens of μm. The surface coating 16 can be formed by oxidizing the metal forming the roller core. For example, when the roller core 15 is made of iron, an iron oxide coating is formed as the surface coating. You can Further, the surface coating can also form a heating roller by coating a metal oxide different from the metal forming the roller core. Further, the roller core may be made of a plastic material or the like, and the surface of the roller core made of plastic may be coated with a means for thinly coating the metal oxide.

An oil applying device 17 is arranged with respect to the heating roller 11, and by pressing the web 18 of the oil applying device 17 against the surface of the heating roller 11,
Oil can be supplied to the roller surface. In the present invention, means for accommodating the modified silicone oil in the oil application device 17 and applying the modified silicone oil to the surface of the heating roller 11 is used. As the modified silicone oil, for example, a commercially available silicone oil such as mercapto modified silicone oil or amino modified silicone oil can be used. Then, the property that these modified silicone oils are retained by the metal oxide can be utilized to prevent the adhesion of the toner to the heating roller.

In the fixing device of the present invention configured as described above, for example, when the roller core is made of aluminum, as shown in FIG. 3, the heating roller 2 is used.
0 is a roller core 21 made of metallic aluminum
An aluminum oxide film 22 can be formed as a surface coating on the surface of the. The aluminum oxide film 22
Can be easily formed by performing an alumite treatment. Since the hardness of the aluminum oxide is extremely high, even if the peeling claw comes into contact with the surface of the roller, the coating on the surface of the roller is not scraped off. Problem does not occur. Further, when the peeling claw is made of plastic or the like, the peeling claw is only worn, and the heating roller body is prevented from being scratched.

As described above, when the roller core is made of another metal material and the surface of the roller is coated with a metal oxide in addition to the case where the roller core is made of aluminum, as shown in FIG. The cross section of the heating roller 25 has a metal oxide film 27 on the surface of a metal roller core 26.
Is formed to have a predetermined thickness, but unevenness occurs on the surface of the oxide film, and many very small recesses 28 are formed. However, since the metal oxide is very hard, polishing it makes the cost very high. Therefore, in the present invention, the recess 28 of the metal oxide coating 27 may be filled with a filling material 29 such as molybdenum sulfide or fluororesin so that the roller surface is not uneven. it can.

When the means for filling the concave portion with molybdenum sulfide is used, it is not necessary to maintain the surface temperature of the roller at 200 ° C. or lower as in the case of fluororesin, and the heating temperature of the roller member can be controlled. Good management is possible. Further, since the molybdenum sulfide has a function as a lubricant, it is possible to reduce the frictional action with respect to a member in contact with the surface of the roller. It is possible to reduce the abrasion effect, and it is possible to improve the durability of both members.

As mentioned above, the metal oxide coating on the surface of the roller core may be a ceramic coating. For example, when the roller core is made of plastic, a ceramic coating is mainly used on the surface of the roller core, and a coating material (for example, “Ceramica” manufactured by Nichibo Kenkyusha Co., Ltd.) is used. By doing so, a ceramic coating can be formed on the surface of the roller core. Further, in the roller member as shown in FIG. 3 as well, after the filler such as molybdenum sulfide is applied to the concave portion of aluminum oxide, the coating material is thinly applied on the surface of the filler, and the ceramic material is baked. Can be formed.

The coating material is alumina-
A silica-based material can be used. It is also possible to use a mixture of the above materials as a main material and fillers of various metal oxides. For example, as the filler, Ni
O, MgO, ZrO ₂ , Fe ₂ O ₃ , TiO ₂ , SnO
_{2. When} the above coating material that can use ZnO is used, the roller core is dipped in a solution of the coating material, and is heated at about 300 ° C. to be fired, so that several μm to several μm A ceramic coating with a thickness of 10 μm can be formed. Therefore, as mentioned above,
When a means for forming a ceramic surface coating on the surface of the roller member is used, the roller core can be made of a material having good workability, such as metal or plastic, and the surface of the roller core has a high hardness metal oxide. It becomes possible to form a film.

The metal oxide coating formed on the surface of the roller core may be formed of an oxide of the same material as the roller core, or may be formed by thermal spraying of a metal oxide. You can When spraying the metal oxide, in addition to aluminum oxide,
In addition to oxides of iron, titanium, magnesium, calcium, nickel, copper and the like, glass and the like can be used. Further, when the roller core is made of aluminum, iron, or the like, it is possible to form a surface coating with its oxide. However, even when it is made of titanium, magnesium, ceramics, nickel, copper, or the like, the roller core can be formed. The surface coating can be formed by the oxide of the material forming the.

When the roller core is made of the above-mentioned material, the surface of the heating roller is very hard and has a good thermal conductivity. Therefore, in the heating roller of the present invention, in addition to disposing the heating source inside the roller core, as shown in FIG. 5, the external heating source 30 is disposed outside the heating roller to heat the heating roller. It can also be configured to provide an action. Further, since the surface of the heating roller is extremely hard, the peeling claw is not made of plastic, and the metal needle-like peeling claw 31 is arranged as shown in FIG. It is also possible to use a peeling means that constantly presses the tip of the needle-shaped peeling claw 31 against the surface of the roller. The other reference numerals in FIGS. 5 and 6 have the same meanings as described above.

As a means for applying the modified silicone oil to the heating roller having the above-mentioned structure, as shown in FIG. 2, in addition to the oil applying device using a web, the applying using a roll is also possible. It is possible to use an oil application device having any other configuration such as a device. Further, the modified silicone oil to be applied to the roller surface may be any one as long as it can chemically bond with the metal oxide and can prevent the toner from adhering to the roller surface in addition to the silicone oil as described above. Modified silicone oils of can be used.

The present invention will be described in more detail with reference to specific examples. However, the present invention is in no way limited by these examples. In the following description, all "parts" represent "parts by weight". (Production Example 1) (Polyester resin A) Bisphenol A-ethylene oxide 2 adduct 21 mol Bisphenol A-propylene oxide 2 adduct 21 mol Succinic acid derivative 7 mol Terephthalic acid 4 mol Trimellitic acid 25 mol Stainless steel stirrer, glass It was put into a four-necked round bottom flask equipped with a nitrogen gas introducing pipe and a flow-down condenser, and heated with a mantle heater while introducing nitrogen gas. Then, the temperature of the reaction product was kept at 200 ° C., and the reaction was carried out for 8 hours while distilling off the produced water. The obtained polyester resin has a weight average molecular weight Mw of about 1
6,000, number average molecular weight Mn = about 3,000, Tg =
The content of THF insoluble matter was 65% at 20%.

(Production Example 2) (Polyester Resin B) The weight average molecular weight Mw is about 9,000 in the same manner as in Production Example 1 except that the monomers are charged and the molar ratio is as follows.
A polyester resin having a number average molecular weight Mn of about 3,500 and Tg of 65 ° C. was obtained. Bisphenol A-ethylene oxide 2 adduct 10 moles Bisphenol A-propylene oxide 2 adduct 15 moles neopentyl glycol 24 moles terephthalic acid 22 moles isophthalic acid 20 moles THF insoluble content was 0%.

In the present invention, the THF-insoluble matter means
It shows the impermeability of filter paper when the sample is dissolved in THF, and can be determined as follows. (1) 200 to 300 mg of a sample is directly weighed into a 25 ml Erlenmeyer flask, 20 ml of THF is put therein, and left overnight. (2) Put the Erlenmeyer flask in (1) above into a Teflon centrifuge tube. (3) The Erlenmeyer flask described in (1) above is rinsed out again with 20 ml of THF, and put in the tube of (2) to make 40 ml, and then sealed. (4) Rotation speed 18,000 rpm, -10 in the above (3)
Centrifuge at 20 ° C. for 20 minutes. (5) The processed product of (4) above is taken out and left to stand until it returns to room temperature. (6) 5 ml of the supernatant of (5) above was weighed out and taken out in an aluminum dish whose weight was measured, and then T
HF is evaporated on a hot plate. (7) The residue of (6) above is placed in a vacuum dryer at 50 ° C. and left overnight to dry, and this is weighed as a toluene-soluble component in 5 ml together with the weight of an aluminum dish. (8) The THF insoluble matter is calculated by the following formula. {<Sample weight>-[(<THF soluble content + aluminum dish weight>-<aluminum dish weight>) x 40 /
5]} ÷ <Sample weight> × 100 = THF insoluble matter (%)

[Example 1] Polyester resin A 80 parts Polyester resin B 20 parts Carbon black (BP1300, manufactured by Cabot) 10 parts Low-molecular polypropylene wax (Viscole 660p, manufactured by Sanyo Chemical Industries) 5 parts It was melt-kneaded with a Banbury mixer. After rolling and cooling, coarse crushing was performed with a hammer mill, followed by fine pulverization with a jet mill and classification to obtain a volume average particle size of 7.5.
μm toner particles were obtained. To 100 parts of the toner particles, 0.5 part of silicone oil-treated silica TS720 (manufactured by Cabot Corporation) was added and mixed with a Henschel mixer to obtain a toner having silicone oil-treated silica fine particles adhered to the surface thereof. As the above toner and carrier,
A developer carrier for FX5039 (manufactured by Fuji Xerox Co., Ltd.) was used and mixed with a V blender to a toner concentration of 6 to 8% to obtain a developer.

The developer thus obtained was modified by FX5039 modified machine (manufactured by Fuji Xerox Co., Ltd .: a fixing device having the structure shown in FIG. 2. An aluminum core was used as the roller core of the heating roller, and an aluminum oxide layer was used as the surface coating. The oil was an amine-modified silicone oil used as the oil).

Example 2 Toner particles were obtained in the same manner as in Example 1, except that 0.7 parts of silica (R972, manufactured by Nippon Aerosil Co., Ltd.) not treated with silicone oil was added to 100 parts of the toner particles. A developer was obtained and tested in the same manner as in Example 1.

Comparative Example 1 A developer was obtained and tested in the same manner except that 100 parts of polyester resin B was used instead of polyester resin A of Example 1. [Comparative Example 2] A developer was obtained and tested in the same manner except that a roller having an aluminum core coated with a fluororesin (Teflon coat) was used in place of the heating roller of Example 1.

[0040]

[Table 1] Heating roller temperature: 200 ° C. Fixing degree: A solid image is folded in two and the degree of image loss is visually compared. Roll stains / scratches: Visual evaluation (visual evaluation of the occurrence of offset).

As is clear from the results shown in Table 1, the image forming method and the image forming apparatus of the present invention having the above-mentioned constitution can shorten the warming-up time, have good fixing degree and offset property, and cause roll scratches. Without doing so, it is possible to prevent copy stains.

[0042]

Since the image forming apparatus of the present invention has the above-mentioned constitution, the modified silicone oil supplied to the surface of the heating roller in the fixing device has a good adhesion property, and prevents the adhesion of the toner and the device. This has the effect of reducing the warm-up time. Further, in the image forming method of the present invention, since a copy image is formed by the above image forming apparatus using the toner composition having the above-mentioned configuration, the toner composition has an extremely wide fixing temperature range when forming the copy image. That is, there is a wide range between the minimum fixing temperature that provides a satisfactory degree of fixing and the maximum temperature that does not cause hot offset, and a defect such as offset does not occur in the fixing device, and a copy image with good image quality can be obtained for a long time It is possible to make over.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus of the present invention.

FIG. 2 is a side view showing a configuration of a fixing device in the image forming apparatus of the present invention.

FIG. 3 is an explanatory diagram of a case where a heating roller is made of aluminum.

FIG. 4 is an enlarged explanatory view when an oxide film is formed on the surface of a metal roller core.

FIG. 5 is an explanatory diagram when a heating source is arranged outside.

FIG. 6 is an explanatory diagram of a case where a peeling claw of another embodiment is provided.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Corona charging device, 3 ... Exposure device, 4 ... Developer carrier, 5 ... Developer, 6 ... Transfer member, 7 ... Transfer means,
10 ... Fixing device, 11 ... Heating roller, 12 ... Pressure roller, 13 ... Heating source, 14 ... Peeling claw, 15 ... Roller core,
16 ... Surface coating, 17 ... Oil applicator, 18 ... Web, 20 and 25 ... Heating roller, 21 ... Roller core,
22 ... Aluminum oxide coating, 26 ... Roller core, 27
... metal oxide coating, 28 ... recessed portion, 29 ... filled material, 30 ...
External heating source, 31 ... Needle-shaped peeling claw.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yusaku Shibuya 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Jun Igarashi, 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Atsumi Kurita 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (6)

[Claims] Forming an electrostatic latent image on an image carrier;
A step of developing the electrostatic latent image with a developer on a developer carrier, a step of transferring a toner image formed on the image carrier to a transfer body, and a heat fixing of the toner image on the transfer body. In the image forming method having a fixing step, the developer containing a toner composition using a binder resin containing 10 to 40% by weight of tetrahydrofuran insoluble polyester resin as a main component is used as the developer. A means for applying a modified silicone oil to the surface of the heating roll, the heating roller having a smooth surface covered with a layer of metal oxide and provided with a heating source, and the pressure roller are provided to face each other. An image forming method, characterized in that the image is fixed by using an apparatus having. 2. The image forming method according to claim 1, wherein the toner composition contains silica treated with silicone oil. 3. The image forming method according to claim 1, wherein the toner composition contains silica treated with silicone oil in an amount of 0.05 to 2.5% by weight based on the toner. 4. The image forming method according to claim 1, wherein the heating roller comprises a metal oxide layer provided on a metal core. 5. A latent image forming means for forming an electrostatic latent image on an image carrier, a developing means for developing the electrostatic latent image using a developer on a developer carrier, and a developing means on the image carrier. It has a transfer means for transferring the formed toner image onto a transfer body and a fixing means for heating and fixing the toner image on the transfer body, and contains, as a developer, a polyester resin having a tetrahydrofuran insoluble content of 10 to 40% by weight as a main component. In an image forming apparatus using a toner composition containing a binder resin, the fixing unit has a smooth surface covered with a metal oxide layer, and a heating roller provided with a heating source. An image forming apparatus comprising a pressure roller and a means for applying a modified silicone oil to the surface of the heating roll so as to face the pressure roller. 6. The image forming apparatus according to claim 5, wherein the heating roller comprises a metal core and a metal oxide layer provided on the metal core.