JP3423616B2 - Fixing device and image forming 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 fixing device of an image forming apparatus for forming a visible image on a recording material by an appropriate image forming process such as an electrophotographic process and an electrostatic recording process.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine, a printer and a facsimile, an image forming unit directly forms a recording medium (electrofax sheet, electrostatic recording sheet, transfer material sheet, printing paper, etc.). Alternatively, a visible image corresponding to a target image is formed and carried by an indirect (transfer) method, and the visible image on the recording medium is heated and pressed by an image heating means to fix the visible image on the recording medium.

As the image heating means of the image forming apparatus, a so-called heating roller type fixing device has been widely used conventionally. As shown in FIG. 10, a heating source is provided inside the pair of rollers, and the rollers are rotated while applying an appropriate pressure between the rollers so that the recording material on which the toner is transferred is passed between the pair of rollers to fix the toner. Is going.

[0004]

However, as disclosed in, for example, Japanese Unexamined Patent Publication No. 6-67504, when a toner generated by a polymerization method (hereinafter referred to as a polymerized toner) is fixed by such a fixing device, Due to the good fluidity of the toner, the image may be disturbed by a rush shock when the recording material rushes between the rollers.

[0005]

According to the present invention, there is provided a fixing member having a heating source, which forms a nip portion for sandwiching and conveying a recording material carrying an unfixed toner, and fixing the unfixed toner image by heat. , A pre-fixing heating unit that is located on the upstream side of the nip with respect to the recording material conveyance direction and heats the recording material and the unfixed toner image in a non-contact manner. A fixing device having a heating passage on the upstream side for heating the recording material by the pre-fixing heating means,
The spherical toner contains a release agent that separates the fixing member from the toner, and heat is applied by the pre-fixing heating means in the heating passage so that the melting point of the release agent becomes lower than the surface temperature of the recording material. The recording material is heated.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus. The image forming apparatus of this example is an electrophotographic full color printer.

Reference numeral 11 denotes an electrophotographic photosensitive drum as an image bearing member, which includes OPC (organic photosensitive member), amorphous Se,
A photosensitive material layer such as amorphous Si is formed on a cylindrical substrate (base) such as aluminum or nickel, and is rotated in the counterclockwise direction indicated by an arrow at a predetermined process speed (peripheral speed).

The photosensitive drum 11 is subjected to a uniform charging process of a predetermined polarity and potential by a charging device 12 such as a charging roller during its rotation process.

Next, the laser scanner 1 is placed on the charging surface.
The laser beam 13 output from 0 receives the scanning exposure processing of the target image information. The laser scanner 10 outputs a laser beam 13 modulated (turned on / off) in response to a time-series electric digital pixel signal of target image information from an image signal generator such as an image reading device (not shown), and the mirror 1
The surface of the rotary photosensitive drum is scanned and exposed via 9 to form an electrostatic latent image corresponding to the target image information on the surface of the rotary photosensitive drum 11 by scanning exposure.

In the case of forming a full-color image, scanning exposure and latent image formation are performed on the first color-separated component image of the target full-color image, for example, the yellow component image, and the latent image is formed by the four-color developing device 14. Yellow developing device 1
By the operation of 4Y, it is developed as a yellow toner image. The yellow toner image is a primary transfer portion T1 which is a contact portion (or a proximity portion) between the photosensitive drum 11 and the intermediate transfer drum 15.
Is transferred onto the surface of the intermediate transfer drum 15. After the transfer of the toner image onto the surface of the intermediate transfer drum 15, the surface of the rotary photosensitive drum 11 is cleaned by a cleaner 17 after removing adhering residues such as transfer residual toner.

The process cycle of charging, scanning exposure, development, primary transfer, and cleaning as described above is performed by the second color separation component image (for example, magenta component image, magenta developing device 14M is operated) of the target full-color image, The color separation component images of the third color separation component image (for example, the cyan component image and the cyan developing device 14C operate) and the fourth color separation component image (for example, the black component image and the black developing device 14BK operate) are sequentially executed. Then, toner images of four colors of yellow toner image, magenta toner image, cyan toner image, and black toner image are sequentially transferred onto the surface of the intermediate transfer drum 15 in a superimposed manner,
A color toner image corresponding to the target full-color image is synthetically formed.

The intermediate transfer drum 15 has a medium resistance layer and a high resistance surface layer on a metal drum.
Is rotated in the clockwise direction indicated by the arrow at substantially the same peripheral speed as the photosensitive drum 11 in contact with or close to the intermediate transfer drum 15
A bias potential is applied to the metal drum to transfer the toner image on the photosensitive drum 11 side to the surface side of the intermediate transfer drum 15 by the potential difference from the photosensitive drum 11.

The color toner image synthetically formed on the surface of the rotary intermediate transfer drum 15 is the rotary intermediate transfer drum 1.
In the secondary transfer portion T2 which is the contact nip portion between the transfer roller 5 and the transfer roller 16, the secondary transfer portion T2 is transferred onto the surface of the recording material C fed at a predetermined timing from a paper feeding portion (not shown). . The transfer roller 16 sequentially transfers the composite color toner image from the surface of the intermediate transfer drum 15 to the recording material C side by supplying an electric charge having a polarity opposite to that of the toner from the back surface of the recording material C.

The recording material C on which the toner image is formed by the image forming means M is separated from the surface of the intermediate transfer drum 15 and is introduced into the image heating device (heat fixing device) R to heat-fix the unfixed toner image. After being subjected to processing (permanent image fixing processing), it is discharged as a full-color image-formed product to a discharge tray (not shown) outside the apparatus. The apparatus of this example can execute not only full-color images but also print modes for mono-color images such as monochrome images.

Next, the fixing device R will be described.

2 is a cross-sectional model view of the fixing device R, FIG. 3 is a model explanatory view of the heating roller R3 of the device, and FIG. 4 is FIG.
FIG. 6 is a schematic cross-sectional view of a fixing film in the fixing device of FIG.

R1 is a fixing roller, R2 is a pressure roller, R
3 is a heating roller, B is a fixing film, H1 and H2 are heating sources having heating elements, S1 and S2 are thermistors as temperature control means, G is a guide member as a recording material support, and P is P.
Indicates a heating passage located upstream of the fixing nip in the conveying direction of the recording material and heating the recording material on which the toner is transferred in a non-contact manner.

The fixing roller R1 is constructed by providing a heat resistant elastic coating layer 2 made of silicone rubber having a thickness of 3 mm on an aluminum core metal 1 having a diameter of 34 mm, and the pressure roller R2 is 50 μm on an aluminum core metal 3 having a diameter of 40 mm. The heat-resistant elastic coating layer 4 of silicone rubber is provided, and the surface hardness of the heat-resistant elastic coating layer 2 is set to be equal to or softer than the hardness of the heat-resistant elastic coating layer 4.

The heating roller R3 has an aluminum cored bar 5 having a diameter of 40 mm and a Teflon coating layer 6 having a thickness of 30 μm, and a step portion 7 which is larger than the thickness of the fixing film B at both ends in the axial direction as a measure for preventing the fixing film B from slipping. Is configured as a stepped roller having (See Figure 3).

The fixing film B which is an endless belt member,
An endless film main body B1 of electroformed metal nickel having a thickness of 40 μm and a release layer B2 made of silicone rubber having a thickness of 100 μm provided on the outer peripheral surface thereof, or a thickness of 55
The endless film main body B1 made of a polyimide resin having a thickness of μm is provided with a release layer B2 made of silicone rubber having a thickness of 200 μm on the outer peripheral surface thereof. In order to further improve durability and releasability, the release layer B2 is formed of tetrafluoroethylene-6 fluoropropylene resin (FE) on the outer peripheral surface of the silicone rubber.
P), etc. are preferably coated with a fluororesin. Further, in order to improve the thermal efficiency of the fixing device, the fixing film B may contain a far infrared substance such as ceramic.

A main heating source H1 is provided inside the heating roller R3, an auxiliary heating source H2 is provided inside the pressure roller R2, and an auxiliary heating source is also provided inside the fixing roller R1 if necessary. Can be provided. Outside the heating roller R3, a thermistor S1 is provided in contact with the fixing film B for controlling the temperature of the main heating source H1, and a thermistor S2 is provided in contact with the pressure roller R2.

As shown in FIG. 2, the guide plate G made of a metal material as a recording material support has a distance of 0 from the fixing film B below the fixing film B from the vicinity of the heating roller R3 to the vicinity of the nip portion N. The toner C1 and the recording material C are preheated in a substantially straight line from the vicinity of the heating roller R3 to the front of the nip portion N between the fixing film B and the fixing film B within a range of 0.5 to 10 mm. A heating passage P is formed. The guide plate G receives the radiant heat from the fixing film B when the paper is not passed and its temperature is raised, and when the paper is passed, the heat is applied to the recording material C to contribute to preheating.

The pressure roller R2 is pressed toward the fixing roller R1 by sandwiching the fixing film B by a pressure means (not shown) to form a nip portion N, and a pressure contact pressure (fixing) at the nip portion N (fixing). Pressure) is 66 kgf. Is set to.

The fixing film B is frictionally charged. Therefore, it is preferable that the surface of the fixing film B is made of silicone rubber when fixing the positive polarity toner having the charging polarity, and the surface of the fixing film B is made of the fluorine resin when fixing the toner having the negative polarity of the charging polarity. . In this way, by selecting the material of the surface of the fixing film according to the charging polarity of the toner, the frictionally charged fixing film B and the toner are electrostatically repelled, and the unfixed toner on the recording material is fixed in the heating path P. Adhesion to the film B can be prevented.

During operation, the fixing film B is at the same speed as the conveying speed of the recording material C introduced from the image forming means M side.
It moves linearly from the heating roller R3 to the nip portion N at a linear velocity of 3 mm / s.

In the present embodiment, the temperature of the heating roller R3 is set to 15 so that suitable heat treatment can be performed in these configurations.
0 to 170 ° C., the temperature of the fixing film B in the heating space P is 145 to 165 ° C., and the pressure roller R in the nip portion N.
The heat generation amount of the main heating source H1 is controlled based on the signal from the thermistor S1 so that the temperature of 2 becomes 108 to 123 ° C.

When the recording material C is fed into the heating passage P by the conveying means T, the recording material C comes into contact with the guide plate G and is guided by the guide plate G so as to be in non-contact with and close to the fixing film B. Is conveyed along the film B in the state of
In the carrying process, the recording material C and the unfixed toner C1 are
After being preheated by the radiant heat from the fixing film B moving at the same speed and the heat from the guide plate G that has accumulated heat when the paper is not passed, it is introduced into the nip portion N and adheres to the fixing film B at a predetermined fixing pressure. , The heat from the film B is directly applied and heat treatment is performed.

As described above, in the apparatus of this embodiment, since the heating passage P is provided to preheat the recording material C and the toner C1, the amount of heat applied to the recording material C and the toner C1 in the nip portion N can be reduced, and the nip portion N can be reduced. The temperature can be lowered.

In particular, the fixing film B in contact with the toner C1
Has a small heat capacity and is appropriately set. Therefore, the fixing film B heated when passing through the heating roller R3 is cooled by applying the heat to the toner C1 and the recording material C while passing through the heating passage P and the nip portion N. .

Therefore, the temperature of the fixing film B at the exit of the nip portion N is significantly lower than that of the heat roller of the conventional heating roller type apparatus, and the fixing film B has a good separability from the toner C1. There is. Further, the toner C of the apparatus of this example
Reference numeral 1 denotes a toner that is produced by a polymerization method and contains wax (hereinafter referred to as a polymerized toner). When preheated in the heating passage P, the wax easily exudes, so that the separation property from the fixing film B is good. Has become.

With these configurations, the apparatus of this embodiment can sufficiently secure the separability between the fixing film B and the toner C1 without providing a mechanism for applying oil to the outer periphery of the fixing film, and a fixed image without offset can be obtained. In particular, since the separability is improved by the action of the toner itself due to the preheating, the offset can be prevented without depending on the applied amount of the toner.

Further, the inventors of the present invention have proposed that the OHP sheet (OH
T) As a result of earnest research on good image formation on the toner, a full-color OH having excellent transparency by melting the toner.
When T is prepared, by setting part or all of the wax to form a film appropriately in the apparatus having the above-described structure, a full color OHT can be prepared without offsetting the toner, and a good low temperature fixing property is obtained. It has been found that the above can be exhibited, good offset resistance can be maintained, and the life of the pressure contact member can be extended.

Since the surface hardness of the fixing roller R1 is set to be equal to or softer than the surface hardness of the pressure roller R2, the pressure roller R2 at the nip portion N is set.
Part of the recording material C bites into the fixing roller R1 together with the fixing film B. Therefore, the leading end of the recording material C such as paper coming out of the nip portion N faces downward on the pressure roller R2 side. The separation claw is unnecessary (see FIG. 5).

In a cold region or the like, if the pressure roller R2 is too cold immediately after starting, it may affect the fixing performance. Therefore, in this case, the thermistor S2 is detected so as to reach the above-mentioned predetermined temperature. Auxiliary heating source H2 based on temperature
Heat with. Of course, when fixing the toner, the main heating source H1
Along with this, the auxiliary heating source H2 may be used for heating.

As for the deviation of the fixing film B, FIG.
As shown in FIG. 3, the step portion 7 is provided at both ends of the heating roller R3, and the step h is set to be equal to or more than the thickness of the fixing film B, and the rigidity of the fixing film B is used to correct the step portion 7. To do.

The toner used in this embodiment is spherical, and the degree of spherical is expressed by shape factors SF-1 and SF-2 defined as follows, SF-12 is 100 or more and 140 or less, SF-2 is preferably 100 or more and 130 or less. 100 or more and 120 for SF-2
The following is more preferable.

The shape factors SF-1 and SF-2 of the present invention are
For example, using Hitachi's FE-SEM (S-800), 100 non-magnetic toner particle images of 2 μm or more magnified 1000 times are randomly sampled, and the image information is transmitted through an interface, for example, by Nicole Corporation. It is defined as a value obtained by being introduced into an image analyzer (Luzex III), analyzed, and calculated by the following formula.

[Outer 1]

(Where MXLNG is the absolute maximum length of the particle,
PERI represents the perimeter of the particle, and AREA represents the projected area of the particle. The shape factor SF-1 indicates the degree of roundness of the toner, and the shape factor SF-2 indicates the degree of unevenness of the toner.

In the present invention, such toner is preheated in the heating passage P to change the shape of the toner to lower the fluidity of the toner and prevent the image disturbance due to the rush shock of the recording material.

Further, the toner C1 of this embodiment is preferably a capsule toner (core shell structure toner) in which the binder resin 102 and the wax 101 are contained inside the shell 103 as shown in FIG.

By preheating such a wax-containing toner in the heating passage P, the wax can be easily exuded and the amount of heating at the nip can be suppressed.

The toner having such a capsule structure is preferably wax 1 having a glass transition temperature of the shell 103.
The toner is higher than the melting point of 01 and the glass transition temperature of the binder resin 102, and the melting point of the wax is preferably lower than at least the surface temperature of the recording material in the heating passage P.

Next, the toner used in this embodiment will be described in detail.

First, the wax, which is a release material used in the toner of this embodiment, will be described. The wax used in this example is a binder resin (binder resin) in order to exhibit good fixability and offset resistance (release property).
It is preferable that it has a suitable affinity, is highly hydrophobic, and has a low melting point and low crystallinity. Furthermore, the molecular weight distribution of the wax has at least two peaks and / or shoulders, and the weight average molecular weight (Mw) is 400 or more 4
000 or less, number average quantity (Mn) of 200 or more and 4000
The following is preferable. It has been found that the above-mentioned molecular weight distribution may be achieved either as a single one or as a plurality, and as a result, the crystallinity can be hindered and the transparency can be further improved. Two
The method of blending more than one wax is not particularly limited, but for example, a media type disperser (ball mill, sand mill, attritor, apex mill, fubor mill, handy mill) or the like is used above the melting point of the wax to be blended. It is also possible to melt blend and melt the wax to be blended into the polymerizable monomer and blend with a media type disperser or the like.

At this time, as additives, pigment, charge control agent,
A polymerization initiator or the like may be used.

In this example, the wax has a molecular weight distribution of GP.
C is measured under the following conditions.

(GPC measurement conditions) Device: GPC-150C (Waters Co.) Column: GMH-HT 30 cm 2 stations (manufactured by Tosoh Corporation) Temperature: 135 ° C. Solvent: o-dichlorobenzene (0.1% ionol added) Flow rate : 1.0 ml / min Reagent: 0.15% of the sample is measured under the condition of 0.4 ml injection or more, and the molecular weight calibration curve prepared from the monodisperse polystyrene standard sample is used for calculating the molecular weight of the sample. Further, it is calculated by performing polyethylene conversion using a conversion formula derived from the Mark-Houwink viscosity formula.

The weight average molecular weight (Mw) of the wax is 40.
0 or more and 4000 or less, number average molecular weight (Mn) is preferably 200 or more and 4000 or less, more preferably M
w is 450 or more and 3500 or less, more preferably 500
It is desired that the above is 3000 or less, and the Mn is 200 or more and 3500 or less, and more preferably 250 or more and 3000 or less. If Mw is less than 400 and Mn is less than 200, the blocking resistance of the toner deteriorates. Also, Mw
When the Mn exceeds 4000 and the Mn exceeds 4000, the crystallinity of the wax itself is developed and the transparency is deteriorated.

The wax is the binder resin 10 of the toner.
0 to 40 parts by weight (preferably 2 to 30 parts by weight)
(Parts by weight) It is better to mix.

A mixture containing a binder resin, a colorant and a wax is melt-kneaded, cooled, pulverized and then classified to obtain toner particles. The amount of the wax added in the dry toner manufacturing method is 1 to 10 parts by weight based on 100 parts by weight of the binder resin. Parts, more preferably 2 to 7 parts by weight.

Polymerization method for obtaining toner particles directly by polymerizing a mixture containing a polymerizable monomer, a colorant and a wax.
2 to 40 parts by weight, more preferably 5 to 30 parts by weight, and further preferably 10 to 2 parts by weight with respect to 100 parts by weight of the polymerizable monomer.
It is preferable to use 0 part by weight.

In the polymerizable toner manufacturing method as compared with the dry toner manufacturing method, since the wax usually has a lower polarity than the binder resin, a large amount of wax is easily encapsulated inside the toner particles in the polymerization method in the aqueous medium. Therefore, as compared with the dry toner manufacturing method, the polymerizable toner manufacturing method generally allows a large amount of wax to be contained in the toner, which is particularly effective for the offset prevention effect during fixing.

If the amount added is less than the lower limit, the offset prevention effect tends to decrease, and if it exceeds the upper limit, the blocking resistance effect tends to deteriorate and the offset resistance effect tends to be adversely affected, and drum fusion and sleeve fusion are likely to occur. Further, in the case of a polymerizable toner, a toner having a wide particle size distribution tends to be produced.

In order to obtain a sufficient OHP image with a low heat capacity of the fixing device, it is preferable to reduce the crystallinity of the wax contained in the toner. In addition, there is an interface of partially undissolved toner particles that have not been dissolved even after fixing, and refraction between the release agent layer on the toner layer surface formed by wax after fixing and the toner layer below the release agent layer. If the rate difference is large, this also causes diffuse reflection of light.

The increase in diffused reflection of light leads to a decrease in the brightness of the projected image and a decrease in the sharpness of the color. In particular, when the transmissive overhead projector is used, the decrease in brightness and sharpness becomes more remarkable than when the reflective overhead projector is used.

That is, in order to reduce the crystallinity of the wax, it is important to reduce the crystallinity of the wax alone. Further, the glass transition temperature (Tg) of the binder resin is preferably low in order to prevent the interface of unmelted toner particles from existing in the toner fixing layer. Further, a material having a small melting enthalpy (ΔH), which is the latent heat of wax, is particularly preferable because it can be rapidly melted with a low energy amount.
Further, since the molten wax is rapidly transferred between the binder resin layer and the fixing film to form the release layer, the solubility parameter (SP) between the binder resin and the wax
It is preferable to adjust the difference appropriately.

From this point of view, specific examples preferable for this embodiment will be described in detail below.

Since a polyester resin, a styrene-acrylic resin, an epoxy resin, or a styrene-butadiene resin is often used as a binder resin for toner, the wax used in this example is refracted with these resins. Those having similar rates are preferable. The refractive index difference described below is the length (20 to 30) x width (8) x thickness (3 to 1
The measurement was carried out by preparing a solid sample of size 0), then adding a small amount of bromnaphthalene to the prism surface and placing a solid sample on it in order to improve the adhesion to the prism surface. Further, as a measuring device, for example, an Appe refractometer 2T manufactured by Atago Co. is used.

The difference in refractive index between the binder resin and the wax is
0.18 or less at 25 ° C., more preferably 0.10
The following are particularly effective: When the refractive index difference exceeds 0.18, the transparency of the OHP image is likely to be lowered, and the halftone projection image has a low brightness.

The melting point of the wax used in this example is 30.
~ 150 ° C is preferable, and more preferably 50 ~
120 ° C. is particularly preferred. If the melting point is lower than 30 ° C., the blocking resistance of the toner, the prevention of sleeve contamination and the prevention of contamination of the photosensitive member during copying of a large number of sheets are likely to deteriorate. When the melting point exceeds 150 ° C., excessive energy is required for uniform mixing with the binder resin in the production of the toner by the pulverization method. On the other hand, in the production of toner by the polymerization method, it is preferable that the melting point is lower than 100 ° C. If the melting point of the wax is higher than 100 ° C., the viscosity becomes large when the binder resin is polymerized, and the size of the apparatus becomes large, or the amount of compatibility is limited, and it becomes difficult to add a large amount of wax to the toner. .

The following solubility parameter (SP) values are
Fedors' method using the additivity of atomic groups [Pol
ym. Eng. Sci. , 14 (2) 147 (197)
4)] is used.

The PS value of the wax used in this example is
It is preferably in the range of 7.5 to 9.7. A wax having an SP value of less than 7.5 has poor compatibility with the binder resin used, and as a result, it is difficult to obtain good dispersion in the binder resin. Of the toner easily occurs, and the charge amount of the toner easily changes. Further, it is easy to cause a background fog and a change in density when replenishing toner. When a wax having an SP value of more than 9.7 is used, blocking between re-toners that have been stored for a long time tends to occur. Further, since the compatibility with the binder resin is too good, it is difficult to form a sufficient release layer between the surfaces of the toner layers during fixing, and the offset phenomenon is likely to occur.

As a method of measuring the melt viscosity of the wax used in this example, a method of measuring with a cone plate type rotor (PK-1) with VT-500 manufactured by HAAKE can be mentioned. Melt viscosity at 100 ° C is 1-50
mPas. sec, and more preferably 3 to 30 mPas. Wax compounds having sec are particularly preferred. 1 mPas. When the melt viscosity is lower than sec, the sleeve is liable to be contaminated due to mechanical shearing force when the toner layer is thinly coated on the sleeve with a blade or the like by the non-magnetic one-component developing method. Further, also in the two-component developing method, when developing the toner using the carrier, damage is likely to occur due to the shearing force between the toner and the carrier, and the embedding of the external additive and the toner crushing are likely to occur. 50 mPas. If the melt viscosity exceeds sec, the viscosity of the dispersoid is too high when a toner is produced by the polymerization method, and it is not easy to obtain a toner having a fine particle diameter having a uniform particle diameter. It tends to be a toner with a wide distribution.

The hardness of the wax can be measured, for example, by a measuring method using a Shimadzu dynamic ultra-micro hardness meter (DUH-200). The measurement conditions were 1 using a Vickers indenter under a load of 0.5 g and a load speed of 9.67 mg / sec.
After being displaced by 0 μm, the Vickers hardness is obtained by holding for 15 seconds and analyzing the dents on the sample. As a sample, a mold having a diameter of 20 mmφ is used, and a previously melted sample is molded into a cylindrical shape having a thickness of 5 mm and used. The hardness of the wax used in this example is preferably in the range of 0.3 to 5.0, and more preferably Vickers hardness of 0.5 to 3.0 is particularly effective.

A toner containing a wax having a Vickers hardness of less than 0.3 is likely to be crushed at the cleaning portion of a copying machine in every copying, and toner fusion is likely to occur on the drum surface, resulting in black on the image. Muscles are easily generated. In addition, when multiple image samples are piled up and stored, so-called show-through easily occurs because toner is transferred to the back side. A toner containing a wax having a Vickers hardness of more than 5.0 requires a pressurizing force higher than necessary for a fixing device used for heat fixing, and requires a fixing device having an excessive strength design. If a fixing device that normally applies pressure is used, the offset resistance tends to decrease.

The crystallinity of the wax is preferably 10 to 50%, more preferably 20 to 35%.

When the crystallinity is less than 10%, the toner storability and fluidity tend to be lowered, and when it exceeds 50%, the transparency of the OHP image is apt to be lowered.

The crystallinity in this example is measured by the following calculation formula from the area ratio of the amorphous scattering peak to the crystal scattering peak without using a calibration curve.

[Outside 2]

As a measuring device, for example, a rotor flex RU300 (Cu target, point focus, output 50 KV / 250 mA) manufactured by Rigaku Denki Co., Ltd. can be mentioned. The measurement method uses the transmission method-rotation method, and the measurement angle is 2θ.
= 5 to 35 °.

As the method for producing the ester wax preferably used in this example, for example, a synthetic method by an oxidation reaction, a synthetic method from a carboxylic acid and its derivative, an ester group introduction reaction represented by a Michael addition reaction and the like are used. A particularly preferred method for producing the ester wax used in this example is a method utilizing a dehydration condensation reaction from a carboxylic acid compound and an alcohol compound or a reaction from an acid halide and an alcohol compound because of the variety of raw materials and the ease of reaction. Particularly preferred.

[Outside 3]

In order to transfer the above-mentioned ester equilibrium reaction to the production system, a large excess of alcohol is used or the reaction is carried out by using a Dean-Stark water separator in an aromatic organic solvent capable of azeotroping with water. . Further, a method of using an acid halogen compound and adding a base as an acceptor of an acid by-produced in an aromatic organic solvent to synthesize polyester can also be used.

Next, the binder resin used in the toner of this embodiment will be described.

Since the shape of the toner changes in the heating passage P, the binder resin used in the toner of this embodiment is preferably a binder resin having a melt viscosity of 1 × 10 ⁶ cp or less while passing through the heating passage P. .

As the binder resin of this example, the following binder resins can be used.

For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene and their substitution products; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-
Vinyl naphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. Preferred binder materials are styrenic copolymers or polyester resins.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate,
Duplex such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide etc. A monocarboxylic acid having a bond or a substituted product thereof;
A dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like; and substituted products thereof; for example, vinyl chloride, vinyl oxide,
Vinyl esters such as vinyl benzoate; ethylene-based olefins such as ethylene, propylene, butylene; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone; vinyl vinyl ether, vinyl ethyl ether, etc. Vinyl monomers such as vinyl ethers such as vinyl isobutyl ether; etc. are used alone or in combination of two or more.

The number average molecular weight of the THF-soluble component of the binder resin of this example is preferably 3,000 to 1,000,000.

The styrene-based polymer or styrene-based copolymer may be crosslinked or may be a mixed resin thereof.

As the crosslinking agent for the binder resin, a compound mainly having two or more polymerizable double bonds may be used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol acrylate, ethylene glycol dimethacrylate and 1,3-butadiol dimethacrylate;
Divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having 3 or more vinyl groups are used alone or as a mixture. The addition amount is preferably 0.001 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

The toner of this example may contain a charge control agent.

The following substances control the toner to be negatively charged.

For example, organic metal compounds and chelate compounds are effective, and there are monoazo metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal compounds. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

Further, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, silicon compounds,
Examples thereof include a styrene-acrylic acid copolymer, a styrene-methacrylic acid copolymer, a styrene-acrylic-sulfonic acid copolymer, and a nonmetal carboxylic acid compound.

The following substances control the toner to be positively charged.

Modified products of nigrosine and fatty acid metal salts and the like, quaternary ammonium salts such as guanidine compounds, imidazole compounds, tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium toterafluoroborate and the like. Onium salts such as phosphonium salts which are analogs, lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as a laker, phosphotungstic acid,
Phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide,
Ferrocyanide, etc.) Metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate,
Diorgano tin borates such as dicyclohexyl tin borate; these can be used alone or in combination of two or more kinds. Of these, charge control agents such as nigrosine type and quaternary ammonium salts are particularly preferably used.

These charge control agents are preferably used in an amount of 0.01 to 20 parts by weight (more preferably 0.5 to 10 parts by weight) per 100 parts by weight of the resin component.

The coloring agents used in this example are carbon black as a black coloring agent, a magnetic substance, and yellow /
A black-colored toner using a magenta / cyan colorant is used.

As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 109, 110,
111, 128, 129, 147, 168, 180 etc. are used suitably.

As the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound and a perylene compound are used. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5,202,206,220,221,254 are particularly preferred.

As the cyan colorant used in this example,
The phthalocyanine compound and its derivative, anthraquinone compound, basic dye lake compound, etc. can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 1
5: 1, 15: 2, 15: 3, 15: 4, 60, 62,
66 and the like can be preferably used. These colorants may be used alone or in combination, and may be used in the form of solid solution. The colorant of this example has hue angle, saturation, lightness, weather resistance, O
HP transparency and dispersibility in the toner are selected.
The amount of the colorant added is 1 to 20 with respect to 100 parts by weight of the resin.
Used by adding parts by weight.

Further, the toner of this example can be used as a magnetic toner by further containing a magnetic material. In this case, the magnetic material can also serve as a coloring agent. In this example, the magnetic material contained in the magnetic toner includes iron oxide such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel; or aluminum, cobalt, copper, lead, magnesium, and tin of these metals. , Zinc, antimony, beryllium, bismuth, cadmium,
Examples thereof include alloys and mixtures of metals such as calcium, manganese, selenium, titanium, tungsten and vanadium.

The magnetic material used in this example is more preferably a surface-modified magnetic material, and when it is used in a polymerization toner, it is treated with a surface modifier which is a substance that does not inhibit polymerization. Any surface-treated material may be used, and examples of such a surface modifier include a silane coupling agent and a titanium coupling agent.

These ferromagnetic materials have an average particle size of 2 μm or less, preferably about 0.1 to 0.5 μm. The amount contained in the toner is preferably 40 to 150 parts by weight with respect to 100 parts by weight of the resin component.

The magnetic properties under application of 10 K oersted are as follows: coercive force (Hc) 20 to 30 oersted, saturation magnetization (σs) 50 to 200 emu / g, residual magnetization (σr) 2.
It is preferably about 20 emu / g.

As an additive for imparting various toner characteristics, from the viewpoint of durability in the toner or when added to the toner, the particle diameter is not more than ⅕ of the volume average diameter of the toner particles. Is preferred. The particle size of the additive means the average particle size thereof obtained by observing the surface of the toner particles with an electron microscope. As the additives for imparting these characteristics, for example, the following ones are used.

Examples of the fluidity-imparting agent include metal oxides (silicon oxide, aluminum oxide, titanium oxide, etc.) carbon black, carbon fluoride and the like. Those subjected to a hydrophobic treatment are more preferable.

As the polishing agent, metal oxides (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metal salts (calcium sulfate, etc.) , Barium sulfate, calcium carbonate, etc.).

Examples of the lubricant include fluororesin powder (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.) and the like.

Examples of the charge controllable particles include metal oxides (tin oxide, titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.) and carbon black.

These additives are used in an amount of 0.1 to 10 parts by weight, preferably 100 parts by weight, based on 100 parts by weight of toner particles.
1 to 5 parts by weight are used. These additives may be used alone or in combination.

The toner of this example can be used as a one-component type developer and a two-component type developer, and can be used for any of the developers.

For example, in the case of a magnetic toner in which a magnetic material is contained in the toner as the one-component developer, there is a method of using a magnet incorporated in the developing sleeve to convey and charge the magnetic toner. . When a non-magnetic toner containing no magnetic material is used, there is a method in which a blade and a fur brush are used to force the toner to be triboelectrically charged by a developing sleeve so that the toner adheres to the sleeve to carry the toner.

On the other hand, when it is used as a commonly used two-component developer, a carrier is used together with the toner of this example to use it as a developer. The carrier used in this example is not particularly limited, but it is mainly composed of iron, copper, zinc, nickel, cobalt, manganese, and chromium elements in a single or composite ferrite state. The carrier shape is also important from the viewpoint that saturation magnetization and electric resistance can be controlled in a wide range, and it is preferable to select, for example, a spherical shape, a flat shape, or an amorphous shape, and further control the fine structure of the carrier surface state, for example, surface irregularity. . Generally, a method is used in which the inorganic oxide is fired and granulated to form carrier core particles in advance and then coated on a resin.
From the point of reducing the load on the toner of the carrier, after kneading the inorganic oxide and the resin, pulverizing and classifying to obtain a low-density dispersed carrier, and further, directly kneading the inorganic oxide and the monomer in an aqueous system. It is also possible to use a method of obtaining a polymerized carrier by suspension polymerization in a medium to obtain a spherical dispersion carrier.

A system in which the surface of the carrier is coated with a resin or the like is particularly preferable. As a method therefor, any conventionally known method such as a method of dissolving or suspending a coating agent such as a resin in a solvent and applying the coating agent and adhering it to a carrier, or a method of simply mixing with a powder can be applied.

The substance adhered to the surface of the carrier varies depending on the toner material, and examples thereof include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of tert-butyl salicylic acid, and styrene type. Resin, acrylic resin, polyamide, polyvinyl butyral, nigrosine, amino acrylate resin, basic dye and its lake, silica fine powder, alumina fine powder, etc. are suitable to be used alone or in a plurality, but are not necessarily limited thereto. .

In general, the treatment amount of the above compounds is preferably 0.1 to 30% by weight (preferably 0.5 to 20% by weight) based on the carrier of this example.

The average particle size of these carriers is 10 to 100.
It is preferable that the thickness is μm, preferably 20 to 50 μm.

In a particularly preferred embodiment, ferrite is used, and the surface thereof is a combination of a resin such as a fluorine resin and a styrene resin, for example, poly (vinylidene fluoride) and styrene-methyl methacrylate resin; polytetrafluoroethylene and styrene-methyl meta resin. Acrylate resin,
Fluorine-based copolymer and styrene-based copolymer;
10 to 20:80, preferably 70:30 to 30:70
A mixture of ratios or silicone resin,
The coated ferrite carrier may be 0.01 to 5% by weight, preferably 0.1 to 1% by weight. As the fluorine-based copolymer, vinylidene fluoride-tetrafluoroethylene copolymer (10:90 to 9)
0:10) is exemplified, and as a styrene-based copolymer, styrene-2-ethylexyl acrylate (20: 80-
80:20), styrene-2-ethylexyl acrylate-methyl methacrylate (20-60: 5-30: 10).
˜50) are illustrated.

The above-mentioned coated ferrite carrier has a sharp particle size distribution, and it is possible to obtain a preferable triboelectrification property for the toner of this example, and further it is effective in improving the electrophotographic characteristics.

When a two-component developer is prepared by mixing with the toner in this example, the mixture ratio is 2% by weight to 15% by weight, preferably 4% by weight as the toner concentration in the developer.
Good results are usually obtained when the amount is -13% by weight. If the toner density is less than 2%, the image density is low and it becomes impossible to use.
If it is 15% or more, fog and scattering in the machine are increased, and the useful life of the developer is shortened.

Further, the magnetic properties of the carrier are as follows. Saturation magnetization needs to be 20 to 90 Am2 / kg. In order to achieve higher image quality, it is preferably 30 to 70 Am2 / kg. 90 Am2
When it is larger than / kg, it becomes difficult to obtain a high quality toner image. If it is less than 20 Am2 / kg, the magnetic restraining force also decreases, and carrier adhesion is likely to occur.

The method for producing the pulverized toner in this example is as follows: binder resin, the above-mentioned ester wax of this example, a pigment as a colorant, or a dye, a magnetic substance, a charge control agent, and other additives as required. Is a Henschel mixer, a ball mill, and the like, and then sufficiently mixed by a mixer such as a heating roll, a kneader, and melt kneading using a heat kneader such as an extruder, in which the resins are mutually compatible and a metal compound, a pigment, The toner according to this example can be obtained by dispersing or dissolving a dye and a magnetic substance, cooling and solidifying, and then pulverizing, spheroidizing, forming a shell, and classifying.

Further, if desired, desired additives may be sufficiently mixed with a mixer such as a Henschel mixer to obtain the toner for developing an electrostatic image according to this example.

The method for producing a polymerized toner used in this example is the method described in Japanese Patent Publication No. 56-13945, in which a molten mixture is atomized into the air using a disk or a multi-fluid nozzle to obtain spherical toner. JP-B-36-10231, JP-A-59-53856, JP-A-59-6
No. 1842, a method of directly producing a toner by using a suspension polymerization method, or a dispersion method of directly producing a toner by using an aqueous organic solvent in which a monomer is soluble and the obtained polymer is insoluble Emulsion polymerization method represented by a soap-free polymerization method in which a toner is polymerized directly or in the presence of a water-soluble polar polymerization initiator to form a toner, or after preparing primary polar emulsion polymerization particles in advance, polar particles having opposite charges It is possible to produce a toner by using a hetero-aggregation method or the like of adding and associating.

However, in the dispersion polymerization method, the toner obtained has an extremely sharp particle size distribution, but the selection of materials to be used is narrow and the use of organic solvents is related to the treatment of waste solvents and the flammability of solvents. From the viewpoint, the manufacturing device is complicated and easily complicated. The emulsion polymerization method typified by soap-free polymerization is effective because the particle size distribution of the toner is relatively uniform, but the environmental characteristics deteriorate when the emulsifier or initiator end used is present on the toner particle surface.

In this example, a fine particle toner having a sharp particle size distribution can be obtained relatively easily under normal pressure, or
The suspension polymerization method under pressure is particularly preferable. A so-called seed polymerization method in which a monomer is further adsorbed to the obtained polymer particles and then the polymerization is performed using a polymerization initiator can be suitably used in this example.

A more preferable toner used in this example is
It was produced using a direct polymerization method. The ester wax is included in the outer shell resin layer that is the shell.
From the viewpoint of fixability, a large amount of ester wax is preferably contained in the toner, and a toner in which the ester wax is encapsulated with an outer shell resin is particularly preferable.

As a specific method for encapsulating the ester wax, the polarity of the material in the aqueous medium is set to be smaller for the ester wax than for the main monomer, and a smaller amount of resin or monomer having a large polarity is used. Can be added to obtain a toner having a so-called core-shell structure in which an ester wax is coated with an outer shell resin. Toner particle size distribution control and particle size control are carried out by changing the type and amount of dispersant that acts as a water-soluble inorganic salt or protective colloid, and mechanical equipment conditions such as rotor speed, number of passes, stirring blade shape. By controlling the stirring conditions such as the above, the shape of the container, the solid content concentration in the aqueous solution, and the like, the predetermined toner of this example can be obtained.

In the present example, the cross-sectional surface of the toner has a temperature of 4 after the toner is sufficiently dispersed in an epoxy resin that is curable at room temperature.
The cured product obtained by curing for 2 days in an atmosphere of 0 ° C. is dyed with ruthenium tetraoxide and, if necessary, osmium trioxide together, and then cut into flaky samples using a microtome equipped with diamond teeth. It measured using the transmission electron microscope (TEM). In this example, it is preferable to use the ruthenium tetroxide dyeing method in order to make a contrast between the materials by utilizing a slight difference in crystallinity between the ester wax used and the resin constituting the outer shell.

When the direct polymerization method is used in the toner manufacturing method of this embodiment, the toner can be specifically manufactured by the following manufacturing method. Ester wax, colorant, charge control agent, polymerization initiator and other additives are added to the monomer, and the monomer system is uniformly dissolved or dispersed by a homogenizer, ultrasonic disperser, etc. Disperse it in the aqueous phase using an ordinary stirrer, homomixer, homogenizer, etc. Granulation is preferably performed by adjusting the stirring speed and time so that the monomer droplets have the desired toner particle size. After that, stirring may be performed to the extent that the particle state is maintained and the particles are prevented from settling by the action of the dispersion stabilizer. Polymerization temperature is 40
Polymerization is carried out at a temperature of not lower than 0 ° C, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction, and further,
In order to remove unreacted polymerizable monomers and by-products that may cause odor during toner fixing, the aqueous medium may be partially distilled off in the latter half of the reaction or after the completion of the reaction. After the reaction is completed, the produced toner particles are collected by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.

When the toner is directly obtained by the polymerization method, the polymerizable monomer may be styrene, o (m-, p).
-)-Methylstyrene, m (p-)-ethylstyrene and other styrenic monomers; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
Butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dimethyl (meth) acrylate (Meth) acrylic acid ester-based monomers such as aminoethyl and diethylaminoethyl (meth) acrylate; ene-based monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylic acid amide are preferably used.

In this example, in order to form the core-shell structure, it is essential to use a polar resin together,
The polar polymers and copolymers that can be used in this example are shown below.

Polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, copolymers with styrene-unsaturated carboxylic acid esters, nitrile monomers such as acrylonitrile, vinyl chloride and the like. Halogen-containing monomers, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, other unsaturated dibasic acids,
Unsaturated dibasic acid anhydrides, polymers such as nitro monomers or copolymers with styrene monomers, polyesters,
Epoxy resin etc. are mentioned. More preferable examples include copolymers of styrene and (meth) acrylic acid, maleic acid copolymers, saturated polyester resins, and epoxy resins.

Examples of the polymerization initiator include 2,2'-
Azobis- (2,4-dimethylvaleronitrile), 2,
2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2 ′
-Azobis-4-methoxy-2,4-dimethylvaleronitrile, azo-based or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxy carbonate, cumene hydroperoxide, t- Butyl hydroperoxide, di-t-butyl peroxide, dixyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butyl) A peroxide initiator such as (peroxy) triazine, a polymer initiator having a peroxide in the side chain, a persulfate such as potassium persulfate or ammonium persulfate, and hydrogen peroxide are used.

The polymerization initiator is a polymerizable monomer of 0.5 to 20.
The addition amount of parts by weight is preferable, and they may be used alone or in combination.

In this example, a known crosslinking agent or chain transfer agent may be added to control the molecular weight,
The preferable addition amount is 0.001 to 15 parts by weight.

In this example, any suitable dispersion medium can be used for producing the polymerization toner by emulsion polymerization, dispersion polymerization, suspension polymerization, seed polymerization, polymerization method using hetero-aggregation method, or the like. Use different stabilizers. For example, as the inorganic compound, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate. , Bentonite, silica, alumina and the like. As organic compounds, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and its salts, starch, polyacrylamide, polyethylene oxide, poly (hydroxystearic acid-g-methacrylic acid) A methyl-eu-methacrylic acid) copolymer, a nonionic or ionic surfactant, etc. are used.

When the emulsion polymerization method or the heteroaggregation method is used, an anionic surfactant, a cationic surfactant, a zwitterionic surfactant and a nonionic surfactant are used. It is preferable to use 0.2 to 30 parts by weight of these stabilizers per 100 parts by weight of the polymerizable monomer.

When an inorganic compound is used among these stabilizers, a commercially available product may be used as it is, but the inorganic compound may be produced in a dispersion medium in order to obtain fine particles.

For fine dispersion of these stabilizers, 0.001 to 0.1 part by weight of surfactant may be used. This is for promoting the intended action of the dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate and sodium tetradecyl sulfate,
Examples thereof include sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like.

As the colorant used in the polymerization toner in this example, it is necessary to pay attention to the polymerization inhibitory property and the water phase transfer property of the colorant, and the colorant is preferably surface-modified. For example, it is better to carry out a hydrophobic treatment that does not inhibit polymerization. In particular, since many dyes and carbon black have a polymerization inhibitory property, caution is required when using them.
A preferred method for surface-treating a dye system is a method of preliminarily polymerizing a polymerizable monomer in the presence of these dyes, and the obtained colored polymer is added to the monomer system. In addition to carbon black, the carbon black may be treated with a substance that reacts with the surface functional groups of carbon black, such as polyorganosiloxane.

As described above, according to this embodiment, the release layer B is formed between the fixing roller R1 and the heating roller R3 on the surface of the film main body B1 made of a metal or resin having a high Young's modulus and heat resistance.
An endless fixing film B having 2 is stretched, and a pressure roller R2 that presses the fixing roller R1 from below through the fixing film B is provided, and a nip portion N is provided between the fixing film B and the pressure roller R2. Constitute. A guide plate G is provided at a position below the fixing film B between the heating roller R3 and the nip portion N, and a substantially linear heating path P is formed between the heating roller R3 and the fixing film B. Recording material C in the heating passage P
After heating the recording material and the toner without contacting the toner C1, the nip portion N applies pressure and heat to fix the visible image on the recording material, and then the fixing film B and the recording material C are separated.

Then, by preheating the highly fluid spherical toner in the heating passage P, the shape of the toner is changed to lower the fluidity of the toner, and the leading edge of the recording material is introduced into the nip portion N. Image distortion due to shock can be prevented.

Further, in the case of a wax-containing toner, preheating in the heating passage P makes it easier for the wax to exude, and the temperature at the nip portion N can be lowered, and the heat-up time can be shortened. Further, it becomes possible to prevent toner offset without applying oil to the fixing film.

Furthermore, a full-color OHP having excellent transparency.
A fixing device that can obtain an image can be provided.

Although the fixing device in which the heating roller R3 is present between the heating source H1 and the fixing film B has been described so far, in the present embodiment, the heating source is a direct fixing film as shown in FIGS. It may be a fixing device for heating.

In the apparatus shown in FIG. 8, a ceramic heater 21 having a resistance heating element is brought into contact with the fixing film B to heat the fixing film B.

In the apparatus shown in FIG. 9, the fixing film F is an electroformed belt of nickel, the coil 22 and the core 23 are arranged as shown in the figure, and the fixing film F is heated by the magnetic flux emitted.

Specific examples of the image forming apparatus of the present invention will be described below.

Specific Example 1 In this example, as the fixing film B (Ni electroformed film 40
The toner is obtained by the following method as the toner, and the other constitution is the same as that of the device of FIG.

The toner of this example is 710 g of ion-exchanged water.
To the above, 450 g of a 0.1 M Na3PO4 aqueous solution was added,
After heating to 60 ° C., the mixture was stirred at 13000 rpm using a TK homomixer (made by Tokushu Kika Kogyo). 68g of 1.0M-CaC12 aqueous solution is gradually added to this,
An aqueous medium containing Ca3 (PO4) 2 was obtained. On the other hand, styrene 166 g n-butyl acrylate, 34 g, same funurolanine pigment 15 g ditertiary butyl salicylate metal compound 3 g saturated polyester (acid value 11, peak molecular weight 8500) monoester wax 140 g (Mw500, Mn400, viscosity 6.5 mPas, SP value 8) -6) The above formulation was heated to 60 ° C and uniformly dissolved and dispersed at 12000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). In this, 10 g of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved,
A polymerizable monomer composition was prepared. The polymerizable monomer composition was put into the aqueous medium, and stirred at 60 ° C. under N 2 atmosphere with a TK homomixer at 10,000 rpm for 20 minutes to granulate the polymerizable monomer composition. . Then, while stirring with a paddle stirring blade, the temperature was raised to 80 ° C.
Reacted for hours.

After completion of the polymerization reaction, the mixture was cooled, hydrochloric acid was added to dissolve calcium phosphate, and then the polymer particles were filtered, washed with water and dried to obtain polymer particles.

BE was added to 100 parts by mass of the obtained particles.
2.0 parts by mass of hydrophobic titanium oxide having a specific surface area according to T method of 100 cm ² / g was externally added to obtain a toner having an average particle size of 6.2 μm.

To 7 parts by mass of this toner, 93 parts by mass of a silicone-coated 35 μm chronite carrier was mixed and used.

The set temperature of each part of the apparatus was changed in multiple stages to fix the toner image on the plain paper. The results of evaluation of fixing performance are shown in Table 1. The following conditions were fixed.

[0147] Linear velocity of fixing film B: 133 mm / s Pressure of the pressure roller R2: 66 kg Distance between fixing film B and guide plate G: 3 mm

[0148]

[Table 1]

Evaluation of fixability / offset occurrence: ○ = good, △ = permissible range, × = defective Remarks: guide plate temperature 100 ° C. (at heating roller 170 ° C.) to 130 ° C. (at heating roller 170 ° C.) [ Specific Example 2 A toner image is fixed on plain paper under the same conditions as in Example 1 except that a fixing device R in which a fixing film B (55 μm of polyimide + 200 μm of silicone rubber) is mounted is used. Table 2 shows the evaluation results.
It was shown to.

[0150]

[Table 2]

Evaluation of fixability / offset occurrence: ○ = good, △ = permissible range, × = defective Remarks: guide plate temperature 100 ° C. (at heating roller 170 ° C.) to 130 ° C. (at heating roller 170 ° C.) [ Specific Example 3 Evaluation was performed in the same manner as in Example 1 except that a developer (toner C1) was prepared using paraffin wax (Mw470, Mn380, viscosity 6.8 mPas, SP value 8-3). Good results were obtained as in Table 1.

[Specific Example 4] Diester wax (Mw 470, Mn 410, viscosity 1)
When evaluation was performed in the same manner as in Example 1 except that Toner C1 was prepared using 0.5 mPas, SP value 9-1), good results were obtained.

[Specific Example 5] Tetraester wax (Mw430, Mn380, and Mw850 has shoulders, and viscosity is 11.6 mPas).
Evaluation was performed in the same manner as in Example 1 except that the toner C1 was prepared using s, SP value 8-5), and good results were obtained.

[Example 6] A quinacridone pigment was used instead of the copper funurolanine pigment.
C. I. Pigment Yellow 180 and carbon black were used to form magenta, yellow, and black developers, and images were formed in the same manner as in Example 1.
The color reproducibility of light colors was excellent and good results were obtained.

[Specific Example 7] The same procedure as in Example 1 was carried out except that 200 g of magnetic iron oxide treated with a silane coupling agent (average particle size of 0.25 μm) was used and a magnetic toner C1 was prepared using a hydrophobic larica. When the images were printed out, good results were obtained.

[0156]

As described above, according to the present invention,
By preheating the highly fluid spherical toner in the heating passage P, the shape of the toner is changed to reduce the fluidity of the toner, and the image disturbance due to the rush shock when the leading edge of the recording material is introduced into the nip portion N is prevented. Can be prevented. Further, in the case of a wax-containing toner, by preheating in the heating passage P, the wax easily exudes, the temperature in the nip portion N can be lowered, the heat-up time can be shortened, and the fixing offset can be prevented. be able to.

Further, it becomes possible to prevent toner offset without applying oil to the fixing film.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of an image forming apparatus according to a first embodiment.

FIG. 2 is a schematic vertical sectional view of the fixing device according to the first embodiment.

FIG. 3 is a schematic front view of a heating roller in the fixing device of FIG.

FIG. 4 is a schematic cross-sectional view of a fixing film in the fixing device shown in FIG.

5 is a cross-sectional view of a main part of the fixing device in FIG.

FIG. 6 is an explanatory diagram of shape factors SF-1 and SF-2.

FIG. 7 is a cross-sectional view showing the structure of a toner containing wax.

FIG. 8 is a vertical cross-sectional schematic view of another example of the fixing device of the first embodiment.

FIG. 9 is a schematic vertical cross-sectional view of another example of the fixing device according to the first embodiment.

FIG. 10 is a schematic vertical sectional view of a conventional fixing device.

[Explanation of symbols]

M image forming means R image heating means (fixing device) R1 fixing roller R2 pressure roller R3 heating roller B Fixing film B1 film B2 release layer G guide plate P heating passage

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI G03G 9/08 384 (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20 G03G 9 / 00-9/113

Claims (11)

(57) [Claims] 1. A fixing member which has a heating source and which nips and conveys a recording material carrying an unfixed toner, and which fixes the unfixed toner image by heat; A pre-fixing heating unit that is located upstream of the conveyance direction and that heats the recording material and the unfixed toner image in a non-contact manner;
In a fixing device having a heating passage for heating the recording material by a pre-fixing heating means upstream of the nip portion with respect to the conveying direction of the recording material, the fixing member and the toner are released from the spherical toner. A fixing device including a release agent, wherein the recording material is heated by the heat from the pre-fixing heating means in the heating passage so that the melting point of the release agent becomes lower than the surface temperature of the recording material. 2. The pre-fixing heating means has a heating element and an endless belt member heated by the heat of the heating element, and the endless belt member extends to the nip to form a nip together with the fixing member. The fixing device according to claim 1, wherein the fixing device is in contact with the upper toner. 3. The fixing device according to claim 1, wherein the fixing member is a pair of rotating bodies. 4. The fixing device according to claim 2, wherein the endless belt member is covered with a fluororesin. 5. The fixing device according to claim 2, wherein the endless belt member contains a far infrared ray generating substance. 6. The fixing device according to claim 1, wherein the toner on the recording material is a toner formed by a suspension polymerization method. 7. The shape factor SF-1 of the toner on the recording material is 100 or more and 140 or less, and the shape factor SF-2 is 10.
The fixing device according to claim 1, wherein the fixing device is 0 or more and 130 or less. 8. The toner on the recording material has a resin and a release agent inside the resin, and the melting point of the release agent is lower than the glass transition temperature of the resin. 1
Fixing device. 9. The toner on the recording material has an outer shell resin and a binder resin inside the outer shell resin, and the glass transition temperature of the binder resin is lower than the glass transition temperature of the outer shell resin. The fixing device according to claim 1, wherein: 10. A pre-fixing heating means different from the pre-fixing heating means is provided, and the second pre-fixing heating means heats the toner on the recording material at the nip. Fixing device. 11. An image forming apparatus having an unfixed toner image forming means for forming an unfixed toner image on a recording material, the image forming apparatus comprising the fixing device according to any one of claims 1 to 10. An image forming apparatus characterized by the above.