JPH07128902A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To provide an electrostatic charge image developing toner excellent in low-temp. fixability, offset resistance, crushability in production, blocking resistance and developability, enhanced in mechanical impact resistance, excellent in transportability of the waste toner to a developing stage and capable of forming a good picture when used in continuous copying or in a reuse line. CONSTITUTION:The untransferred toner on a latent image carrier is recovered, supplied to a developing part and reused to form a picture. The electrostatic charge image developing toner contains at least a binder resin and a colorant. The binder resin component has a main peak in the mol.wt. range of 5,000-100,000 in the mol.wt. distribution measured by gel permeation chromatography, and the weight average mol.wt. is controlled to >=5,000,000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developing toner having excellent characteristics used in electrophotography, electrostatic printing and magnetic recording, and more particularly, to a latent image carrier after development and transfer. The present invention relates to an electrostatic charge image developing toner (hereinafter referred to as a toner) used in an image forming method that utilizes a system in which residual untransferred toner is collected in a cleaning step and reused.

[0002]

2. Description of the Related Art US Pat.
The methods described in Japanese Patent Publication No. 297,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748 are known. Generally, a photoconductive substance is used to form an electrical latent image on a latent image carrier (photoreceptor) by various means, and then the latent image is developed with toner, and if necessary, After the toner image is transferred onto a transfer material such as paper, the image is fixed by heating, pressurizing, heating and pressurizing, or solvent vapor to obtain a copy. Regarding the step of fixing the toner image to the transfer material such as paper, which is the final step of the electrophotographic method,
Conventionally, various methods and devices have been developed. Currently, the most common fixing method is a pressure heating method using a heat fixing roller.

In the pressure-bonding heating method using a heat fixing roller, the toner image surface on the transfer material is passed under pressure while contacting the surface of the heat fixing roller whose surface is formed of a material having releasability for toner. Fixing is performed by urging. In this method, since the surface of the heat fixing roller and the toner image on the transfer material are brought into contact with each other under pressure, the thermal efficiency at the time of fusing the toner image on the transfer material is extremely good, and quick fixing is required. It is very effective for high speed electrophotographic copying machines.

[0004]

However, in the above-described pressure-bonding heating method, since the surface of the heat fixing roller and the toner image in a molten state come into contact with each other under pressure, a part of the toner image is formed on the surface of the heat fixing roller. There is a problem in that the transfer material adheres to the transfer material, and the transfer material re-transfers to the next transfer material to cause an offset phenomenon, thus contaminating the transfer material. Therefore, preventing the toner from adhering to the surface of the heat fixing roller is one of the important problems in the pressure heating method using the heat fixing roller.

Various methods have been studied so far so as to prevent the toner from adhering to the surface of the heat fixing roller used in the pressure heating method. For example, the surface of the heat fixing roller is formed of a material having excellent releasability for toner (for example, silicone rubber and fluorine resin), and further, in order to prevent offset and fatigue of the surface of the heat fixing roller,
BACKGROUND ART The surface of a roller is coated with a thin film of a liquid having excellent releasability such as silicone oil. However, although this method is extremely effective in preventing toner offset, it requires a device for supplying a liquid for offset prevention, which causes a problem that the fixing device becomes complicated. Therefore, it cannot be said that the direction of preventing the offset by supplying the liquid for the offset prevention to the roller is preferable, but rather, the development of a toner having a wide fixing temperature range and a high offset resistance is desired.

Therefore, in order to increase the releasability of the toner from the heat fixing roller, a method of adding a wax such as low molecular weight polyethylene or polypropylene, which can be sufficiently melted at the time of pressure heating, to the toner is used. But,
The method of using the wax is effective for preventing offset, but has a problem that the aggregation property of the toner is increased, the charging property becomes unstable, and the durability is easily deteriorated.

As another method for preventing the offset phenomenon, various attempts have been made to improve the binder resin constituting the toner. For example, there is known a method of improving the melt viscoelasticity of the toner by increasing the glass transition temperature (Tg) and the molecular weight of the binder resin in the toner in order to improve the offset resistance. However, when the offset phenomenon is improved by such a method, the fixability of the toner becomes insufficient, and the fixability at a low temperature (that is, the low-temperature fixability) required for energy saving of a high-speed copying machine or a developing device. The new problem of being inferior to. On the other hand, in order to improve the low temperature fixability of the toner,
Since it is necessary to reduce the viscosity of the toner during melting and increase the adhesion area with the transfer material, it is required to reduce the Tg and molecular weight of the binder resin used. As described above, since the low temperature fixability and the anti-offset property have one contradictory aspect, it is very difficult to develop a toner satisfying both of them.

In order to solve the above-mentioned problems, for example, Japanese Patent Publication No. 51-23354 discloses a toner which comprises a cross-linked vinyl polymer and a cross-linking agent and a molecular weight modifier. Proposed, and Japanese Patent Publication Sho 55-6
No. 805 discloses that an α, β-unsaturated ethylenic monomer is used as a constitutional unit and the ratio of the weight average molecular weight (M _w ) to the number average molecular weight (M _n ) is 3.5 to 40. In addition, a toner made of a resin having a wide molecular weight distribution has been proposed. Further, there has been proposed a toner using a blend-type resin in which Tg, molecular weight, gel content and the like are defined in a vinyl-type polymer.

However, each of these proposed toners has a lower fixing temperature (the lowest temperature at which fixing is possible) and an offset temperature (an offset phenomenon begins to occur, as compared with a toner made of a single resin having a narrow molecular weight distribution. Temperature range), the fixable temperature range is widened, but when sufficient anti-offset performance is given to the toner, it becomes difficult to lower the fixing temperature sufficiently. The prevention performance was insufficient and it could not be said that both properties were satisfied at the same time.

Further, JP-A-56-158340 proposes a toner containing a binder resin composed of a low molecular weight polymer and a high molecular weight polymer as a component. However, when such a binder resin is used, it is actually difficult to include a cross-linking component, and in order to improve the offset resistance with high performance, the molecular weight of the high molecular weight polymer is increased or the high molecular weight polymer is increased. It is necessary to increase the proportion of molecular weight polymer. Therefore, the pulverizability of the resin composition must be significantly reduced, and it is difficult to obtain a practically satisfactory product.

Further, as a toner comprising a binder resin obtained by blending a low molecular weight polymer and a crosslinked polymer, Japanese Patent Laid-Open No. 58-86558 discloses a low molecular weight polymer and an insoluble infusible high molecular weight polymer. A toner containing a resin component has been proposed. According to this method, it is considered that the fixability of the toner and the pulverizability of the resin composition are improved. However, the weight average molecular weight / number average molecular weight (M _w / M _n ) of the low molecular weight polymer is as small as 3.5 or less,
And the content of insoluble and infusible high molecular weight polymer is 40 to 90w
Since it is as high as t%, it is extremely difficult to produce a toner that satisfies both the offset resistance of the toner and the pulverizability of the resin composition with high performance. That is, in practice, even when the toner as described above is used, it is difficult to satisfy the low-temperature fixability and the offset resistance at the same time unless the fixing device has a device for supplying an offset preventing liquid to the roller. Is. Further, when the content of the insoluble and infusible high molecular weight polymer becomes high, the melt viscosity becomes extremely high at the time of heat kneading at the time of toner production, so that heat kneading at a temperature much higher than usual is required, As a result, there is a problem that the additive is thermally decomposed and the toner characteristics are deteriorated.

Further, in JP-A-60-166958, a resin composition obtained by polymerization in the presence of a low molecular weight α-methylstyrene polymer having a number average molecular weight of 500 to 1,500 is used as a binder. Toners have been proposed. In particular, the publication describes that the number average molecular weight (M _n ) of the obtained resin composition is preferably in the range of 9,000 to 30,000, but in order to improve the offset resistance, M _n When it is increased, the fixability and the pulverizability of the resin composition at the time of toner production become problems in practical use. That is,
It is difficult to satisfy both the offset resistance and the pulverizability of the resin composition at the same time with high performance. Such a toner having a poor pulverizability of the resin composition at the time of toner production reduces the production efficiency at the time of toner production, and since coarse particle toner easily mixes in as a toner characteristic, the toner is not easily formed when an image is formed. The image may be scattered, which is not preferable.

Further, Japanese Patent Application Laid-Open No. 56-16144 discloses that
In the molecular weight distribution by GPC, the molecular weight is 10 ³ to 8 ×
In each region of 10 ⁴ and molecular weight 10 ⁵ to 2 × 10 ⁶ ,
A toner containing a binder resin component having at least one maximum value has been proposed. In this case, it is possible to improve the pulverizability of the binder resin component, the offset resistance of the toner, the low-temperature fixing property, the prevention of filming and fusion on the photoconductor, and the development characteristics to some extent, but the toner offset prevention property. In addition, further improvement in low temperature fixability is desired. In particular, the above toner is not sufficient to satisfy today's strict requirements for further improving low-temperature fixability and maintaining or improving various other performances.

In particular, the pulverizability at the time of toner production is technically required today to make the particle diameter of the toner smaller in response to the demand for high quality, high resolution of copied images and high reproducibility of fine lines. It is an important factor for direction. Further, since such a crushing process requires a very large amount of energy, improvement of crushability is important from the viewpoint of energy saving. From the above viewpoint, it is required to improve the pulverizability of the toner, but if the low-temperature fixability is improved, the toner fusion phenomenon to the inner wall of the pulverizer is likely to occur in the toner having good fixability, and the pulverization efficiency is improved. It may make it worse. As described above, it is extremely difficult to realize both high performances relating to toner fixing (low temperature fixing property and offset preventing property) and pulverizability of the resin composition during toner production with high performance.

In the copying process, there is a process of cleaning the toner remaining on the photoconductor after the transfer. However, cleaning with a blade (blade cleaning) is used today from the viewpoint of downsizing of the apparatus, weighing and reliability. It is commonplace. Further, as the life of the photoconductor is extended, the diameter of the photoconductor drum is reduced, and the speed of the system is increased, the characteristics required for the toner such as the fusion resistance and the filming resistance with respect to the photoconductor are becoming severe. In particular, the amorphous silicon photoconductor that has recently been put into practical use has extremely high durability,
In addition, OPC (organic photoconductor) has a long life,
The various performances required for toner are becoming higher. Also, in order to miniaturize the device, it is necessary to properly store each element in a narrow space, so the space for the cooling air in the device will decrease, and the heat source of the fixing device and the exposure system It comes very close to the toner hopper and cleaner. For this reason, the toner is exposed to a higher temperature atmosphere than in the past, and practical application becomes difficult unless a toner having excellent blocking resistance is used.

As a method for improving the above-mentioned problems, the applicant of the present application has proposed a toner made of a special resin in which a low molecular weight resin is added during suspension polymerization in Japanese Patent Application Laid-Open No. 63-223662. , This toner is also A
When used in a high-speed machine that develops 50 or more sheets per minute on 4 size paper, sufficient low-temperature fixability cannot be obtained yet, and toner from the cleaning member contacting the heat-fixing roller cannot be obtained. A problem has been found that the fixed image is easily stained due to the outflow.

In a high-speed machine with more than 50 sheets per minute, even if the offset amount per sheet is extremely small, the number of sheets passed is enormous, so that the offset material to the heat fixing roller is considerable. This is a large amount and causes a failure of the fixing device. Therefore, in order to remove this minute amount of offset material, a cleaning roller made of silicone rubber or a fixing cleaning member such as a web is attached in contact with the heat fixing roller. Conventional binder resins for toners are designed mainly for low-temperature fixability and anti-offset properties, and are not designed to maintain high melt viscosity up to high temperatures such as over 200 ° C. Therefore,
The toner adhering to the fixing cleaning member remains for a long time under the design temperature conditions of the heat fixing roller, so that the melt viscosity is lowered. Furthermore, when the temperature of the heat fixing roller overshoots the design temperature or more when the switch of the copying machine is turned on, the temperature of the heat fixing roller exceeds 200 ° C.,
The melt viscosity of the adhered toner is remarkably lowered, and the transferred toner is transferred to the heat fixing roller again, which causes the transfer material to be stained.

Therefore, in JP-A-1-172843 and JP-A-1-172844, a molecular weight of 3 × 10
^It has a peak in each region of ^{3 to} 5 × 10 ³ and 1.5 × 10 ^{5 to} 2.0 × 10 ⁶ , and a molecular weight of 1.5 × 10 ⁵ to
The peak area in the area of 2.0 × 10 ⁶ is 40 to 60%
Or a toner having a gel content of 1 to 10% has been proposed. Although this toner is certainly good for medium- and low-speed copying machines, it does not sufficiently cope with offset resistance and low-temperature fixing property in high-speed copying machines.

Further, in the transfer step, the toner on the photoconductor (latent image carrier) is not entirely transferred, and the toner is not transferred.
About 20% by weight remains on the photoreceptor. As described above, the toner (untransferred toner) remaining on the photoconductor was collected by the cleaning process and discharged as so-called waste toner to the outside of the system so that it could not be used again.

In recent years, the demand for copying machines has increased, and the demand for machines having a large copy volume, that is, high-speed copying machines, has further increased. A large amount of waste toner is generated in such a high speed copying machine. If all the waste toner generated in these high-speed copying machines is treated as waste (waste plastic), there is a risk of causing environmental pollution. Therefore, recently, a study of reusing the waste toner, that is, a study of reuse of the toner has been widely conducted. If the waste toner can be reused, it is possible to effectively use the waste toner, simplify the space in the copying machine, and make the copying machine compact.

However, when the waste toner is used again in the developing step, there are adverse effects such as a reduction in the reflection image density of the obtained copy, deterioration of background fog and reversal fog, and occurrence of toner scattering. In order to investigate the cause such as the reduction of the reflection image density when the waste toner is used in the above reuse system, the present inventors collected the toner on the developing sleeve from the start of copying and conducted various studies. . As a result, the toner shape was changed before and after the above-mentioned adverse effects began to occur. That is, when the toner on the developer sleeve is observed with a scanning electron microscope (SEM) at any time, the surface of the waste toner, which is a harmful toner, peels off,
Alternatively, it was confirmed that there were many pieces that were crushed from the inside.

When the reason for this is further examined, when untransferred toner (waste toner) on the photoconductor is scraped off by the cleaning blade in the cleaning process, or when it is conveyed again to the developing process using the conveying screw. It was found that the mechanical shock exerted during the operation was a major factor. Therefore, the toner applied to the reuse system has the above-mentioned characteristics, that is, developability, low-temperature fixability,
In addition to offset resistance, blocking resistance, fishing resistance, crushability, etc., it is also resistant to mechanical impact, has excellent durability, and has excellent transportability to the development process. Is also required. However, a toner satisfying all of these has not been known.

To meet these demands, various toners have been proposed so far. For example, JP-A 1-2
JP-A-14874 discloses a toner using a specific polyester resin containing an aliphatic diol as a binder resin,
Further, JP-A-2-110572 proposes a toner in which a metal-crosslinked styrene-acrylic copolymer is used as a binder resin and multiple polyolefins are added to the binder resin. However, in any of the inventions, the toner composition itself is poor in novelty, and there is a high possibility that adverse effects such as deterioration of blocking resistance will occur. As described above, the performances required of toners are often reciprocal with each other, but in recent years, all the performances have been increasingly provided, and even when the waste toner is reused, all of these performances are combined. At present, a satisfactory toner is desired.

Therefore, an object of the present invention is to solve the above problems and provide an electrostatic image developing toner having excellent characteristics in which all the reciprocal performances required of the toner are exhibited in high performance. Further, it is to provide a toner for developing an electrostatic charge image, which is suitable for a recycling system in which waste toner is reused.

The objects of the present invention are listed below. An object of the present invention is to provide a toner suitable for a heat fixing method in which oil is not applied to the surface of a heat fixing roller. An object of the present invention is to provide a toner having excellent low-temperature fixability and offset resistance. The purpose of the present invention is to
It is an object of the present invention to provide a toner having a low temperature fixing property even when it is used in a high speed copying machine, or even when it is used for a long period of time, and which does not cause fusion and filming on a photoreceptor.
An object of the present invention is to provide a toner which has excellent low-temperature fixability and excellent blocking resistance, and can be used sufficiently even in a high temperature atmosphere in a small machine. An object of the present invention is to provide a toner that has excellent low-temperature fixability and that does not cause the pulverized material to adhere to the inner wall of the apparatus in the pulverizing step during toner production, and that can be efficiently and continuously produced. An object of the present invention is to provide a toner having excellent production efficiency because it has excellent offset resistance and crushability. An object of the present invention is to provide a toner suitable for a cleaning method using a blade. An object of the present invention is to provide a toner capable of forming a stable and good developed image because the pulverizability is excellent, the generation of coarse powder is small, and therefore the toner scattering around the image is small. An object of the present invention is to provide a toner that is strong against mechanical shock when used in continuous copying and reuse systems and can form a sharp developed image from beginning to end. It is an object of the present invention to provide a toner that maintains a high reflection image density in an image when waste toner is used in a reuse system and does not cause background fog or toner scattering in the image.

[0026]

The above objects can be achieved by the present invention described below. That is, in the present invention, the latent image on the latent image carrier is developed to form a toner image, the toner image is transferred from the latent image carrier to the transfer material, and then the latent image carrier is cleaned to form the latent image. In an electrostatic charge image developing toner used in an image forming method in which untransferred toner on a carrier is collected, and the collected toner is supplied to a developing unit side and reused in a developing step,
In an electrostatic charge image developing toner containing at least a binder resin and a colorant, the binder resin component has a molecular weight of 5,000 to 10 in a molecular weight distribution measured by gel permeation chromatography (GPC).
A toner for developing an electrostatic charge image, which is a resin having a main peak in the region of 50,000 and having a weight average molecular weight of 5,000,000 or more.

[0027]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, by using a resin component having a specific molecular weight distribution as a binder resin of a toner, the low temperature characteristics which are contradictory to each other. It is possible to satisfy both the fixability and the offset resistance at the same time, and further obtain a toner having excellent pulverizability during production, blocking resistance, and developing characteristics.
In addition, the inventors have found that the toner is resistant to mechanical shock, excellent in durability, and excellent in transportability of waste toner to a developing process, and thus the present invention has been accomplished.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. In the present invention, the main peak (highest peak) in the GPC chromatogram of the binder resin, which is a component of the toner, has a molecular weight of 5,000 to 100,0.
It is characterized in that it is in the region of 00, but it is particularly preferable that the main peak is in the region of molecular weight of 10,000 to 50,000.

When the amount of resin component having a molecular weight of 5,000 or less increases, the toner is in a state of being pressed (for example, in a large toner container having a capacity of 1 kg or more, the weight of the toner is applied and the toner is allowed to stand still. (Unsatisfied state), it is easy to aggregate in the toner container during storage or transportation, and the blocking resistance is poor, which is not preferable. Further, a resin component having a molecular weight of 5,000 or less is a component that can particularly improve the pulverizability of the resin composition during toner production. However, if the content is too large, excessive pulverization occurs during toner production. ,
As the generation of ultrafine powder toner increases, the classification efficiency decreases,
This causes a decrease in toner productivity.

If the toner contains a large amount of ultrafine powder that cannot be classified, the content of the ultrafine powder in the toner gradually increases as the toner is replenished repeatedly. The body adheres to the toner triboelectrification imparting member by electrostatic force, which prevents the triboelectrification of the toner and causes a decrease in image density and fog. On the other hand, a resin component having a molecular weight of 5,000 or less has been conventionally used in order to improve the pulverizability at the time of manufacturing a toner, reduce the partial viscosity of the toner, and assist the improvement of the fixing property of the toner. Therefore, it is preferable to use these resin components in consideration of the above problems, and in the present invention, the effect can be expected if the amount is 2% or more based on the total weight of the resin components.

When there are a plurality of peaks in the molecular weight distribution of the binder resin measured by GPC, a sub-peak (having a height of ½ or more of the main peak)
Is in the molecular weight range of 5,000 to 100,000 is also a preferred embodiment of the present invention.

The resin component having a molecular weight of 10,000 or less functions as a component that plays a role of improving pulverizability during toner production,
The component in the molecular weight range of 5,000 to 100,000 is a component that acts to improve the fixing property of the toner. In order to include these components in a good balance and in a large amount in the resin composition, the main peak is 5,000 to 100,000.
It is necessary to be in the range of 0, and as a result, good pulverizability during toner production and toner fixability can be obtained. Therefore, the molecular weight is 5,000 to 100,000.
In order for the component in the 0 region to become the main component, 5,000
The content of the component in the range of 100,000 to 40% is preferably contained in the total weight of the resin component, and more preferably 45% or more. In addition, it is also one of the preferred embodiments of the present invention that a peak only exists in the molecular weight range of 10,000 to 40,000 as a peak in this molecular weight range.

When a resin having a main peak in a region having a molecular weight of less than 5,000 is used for a toner, not only blocking resistance and offset resistance are insufficient, but also
Due to mechanical shock, the performance of the reusable toner is likely to be impaired. On the other hand, the position of the main peak has a molecular weight of 10
Using a resin that is present in more than 10,000 areas,
Sufficient toner fixability and crushability during toner production cannot be obtained. In addition, the position of the main peak has a molecular weight of 50,0.
When a toner is produced from a resin near 00, the pulverizability gradually starts to decrease.

The resin component contained in the toner of the present invention has a weight average molecular weight (M _w ) of 5,000,000 or more, preferably 6, as an average molecular weight calculated from a GPC chromatogram. , 000,000-20,
One of the features is that it is, 000,000. The fact that the M _{w of the} resin component is 5,000,000 or more does not mean that the weight fraction of the polymer component having M _w of around 5,000,000 is high, but that the components having a molecular weight higher than this range are broad. It means that it is included in the distribution.
That is, in the GPC chart of the resin component, M _w 5,
It means that the distribution around, 000,000 is not a vertically long distribution but a horizontally long distribution. As a result, the connecting portion with other components is efficiently contained, and the dispersibility of the internal additive contained in the toner is improved. Further, there is an advantage that the offset resistance is excellent because the weight fraction of each component having a molecular weight in the high to ultra high molecular weight region is smoothly connected and the offset resistant component is effectively contained.

M of the resin component used in the toner of the present invention
_{If w} is less than 5,000,000, the offset resistance may not be sufficiently obtained, or the toner may be easily crushed by a mechanical shock, and the influence becomes large especially in the untransferred toner. It is not preferable because it may cause a problem in toner performance. On the other hand, when the M _{w of the} resin component is 20,000,000 or more,
It is not preferable because it may cause poor fixing of the toner and poor dispersion of the internal additive during manufacturing. Further, in order to effectively exhibit the fixing property improving component and the pulverizing property improving component of the toner, the number average molecular weight (M _n ) of the resin component is 4
It is 30,000 or less, preferably 30,000 or less, and more preferably 25,000 or less.

Further, the reuse type toner preferably contains an ultra high molecular weight component. In the present invention, Z is used.
The average molecular weight (M _z ) is preferably 20,000,000 or more. In the resin component used in the toner of the present invention,
In order to contain the ultrahigh molecular weight component in a well-balanced manner, the ratio of the Z average molecular weight (M _z ) and the weight average molecular weight (M _w ) (M _z /
M _W ) is 40 or less, preferably 5 to 30.

The molecular weight distribution of the resin component contained in the toner of the present invention is measured under the following conditions by a chromatogram by GPC using tetrahydrofuran (THF) as a solvent. First, a measurement sample is prepared as follows. After mixing the sample (resin component) and THF at a concentration of about 0.5 to 5 mg / ml (for example, about 5 mg / ml), and leaving the mixture at room temperature for several hours (for example, 5 to 6 hours),
Mix well with THF until the samples are thoroughly shaken until they do not coalesce, and then stand at room temperature for 12 hours or longer (for example, 24 hours). At this time, the time from the start of mixing the sample and THF to the end of the standing is set to 24 hours or more. Then, the pore size is 0.45 to 0.
A 5 μm sample processing filter (for example, Myshori disk H-25-2: manufactured by Tosoh Corp., Excicro disk 25CR: manufactured by German Science Co., Ltd., etc. can be preferably used) is used as a measurement sample.
The measurement sample concentration was 0.5 to 5 mg / ml for the resin component.
Adjust so that The resin component used in the toner of the present invention is preferably 10 wt% or less, more preferably 5 wt% or less, as a resin component remaining as an insoluble component in the above filter treatment. .

Next, THF as a solvent is caused to flow through a column previously stabilized in a heat chamber at 40 ° C. at a flow rate of 1 ml / min, and about 100 μl of a THF sample solution is injected to measure a molecular weight distribution. When measuring the molecular weight of a sample,
The molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of the calibration curve prepared from several kinds of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, a standard polystyrene sample having a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh or Showa Denko is used, and it is suitable to use a standard polystyrene sample of at least about 10 points. Is.

A plurality of commercially available polystyrene gel columns may be combined with the column, for example, shodex GPC KF-801, 802, 8 manufactured by Showa Denko KK
A combination of 03, 804, 805, 806, 807 and 800P and TSK gel G100 manufactured by Tosoh Corporation.
0H (H _XL ), G2000H (H _XL ), G3000H
(H _XL ), G4000H (H _XL ), G5000H
(H _XL ), G6000H (H _XL ), G7000H
A combination of (H _XL ) and TSK guardcolumn can be used. An RI (refractive index) detector is used as the detector. Generally, in the measurement of GPC chromatogram, the measurement starts from the baseline starting point of the chromatogram on the high molecular weight side, and the molecular weight up to about 400 on the low molecular weight side. Therefore, this also applies to the present invention.

When the resin composition contained in the toner has an acid value, the releasability between the toner and the heat fixing roller can be increased and the offset resistance of the toner can be improved. Therefore, the resin used in the toner of the present invention is JIS
The acid value of the resin composition measured by the method according to K-0070 is preferably 2 to 100 mgKOH / g, more preferably 5 to 70 mgKOH / g.
When the acid value of the resin composition is less than 2 mgKOH / g,
While the re-crosslinking reaction becomes difficult to carry out sufficiently, the acid value is 10
When it exceeds 0 mgKOH / g, it is not preferable because it is difficult to control the charge of the toner and the developing property of the toner tends to be dependent on the environment.

As the binder resin used in the present invention, various known polystyrene-based, acrylic-based, epoxy-based, polyester-based, polyolefin-based, and rubber-based resins can be used. The main peak of the component is 5,000 to 10
In the region of 10,000 and a weight average molecular weight of 5,0
It is necessary to be at least 0,000. Therefore, in the present invention, by appropriately selecting the polymerization method and the polymerization conditions,
It is necessary to produce a resin that meets the above requirements.

For example, when a bulk polymerization method is used as a polymerization method for obtaining the resin composition used in the present invention, the polymerization is carried out at a high temperature to accelerate the termination reaction rate, thereby lowering the weight of the low molecular weight polymer. Although it is possible to obtain a coalescence, there is a problem that it is difficult to control the reaction. On the other hand, when the solution polymerization method is used, a low molecular weight polymer or copolymer can be obtained by utilizing the difference in the chain transfer of radicals by the solvent or by adjusting the amount of the polymerization initiator or the reaction temperature. It can be easily obtained under mild conditions. Therefore, it is preferable as a polymerization method for obtaining a low molecular weight polymer or copolymer in the resin composition used in the present invention.

Specific examples of the solvent used in the above solution polymerization include xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol and benzene. These solvents are appropriately selected depending on the polymer to be polymerized, but when mixed with a styrene monomer, xylene, toluene and cumene are preferable. or,
The polymerization initiator used in the solution polymerization method, for example,
Di-tert-butyl peroxide, tert-butyl peroxybenzoate, benzoyl peroxide, 2,2'-azobisisobutyronitrile and 2,2
′ -Azobis (2,4-dimethylvaleronitrile) and the like can be mentioned. These polymerization initiators are used in an amount of 0.05 parts by weight or more, preferably 0.1 to 100 parts by weight of the monomers.
Used at a concentration of 15 parts by weight. The polymerization temperature varies depending on the solvent used, the polymerization initiator and the polymer species to be polymerized, but is preferably 70 ° C to 230 ° C. In the solution polymerization, the amount of the monomer 30 to 100 parts by weight of the solvent is 30 to
It is preferable to carry out the reaction at 400 parts by weight. Further, it is also preferable to mix another polymer or copolymer in the solution at the end of the polymerization. In that case, several kinds of polymers or copolymers can be mixed well. The copolymer used in this case may be a block copolymer or a graft product.

As the polymerization method for obtaining the high-molecular weight component in the highly crosslinked region, it is preferable to use an emulsion polymerization method or a suspension polymerization method. Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is performed using a water-soluble polymerization initiator. In this method, the heat of reaction can be easily adjusted, and the termination reaction rate is low because the phase in which the polymerization is carried out (oil phase composed of polymer and monomer) and the aqueous phase are different, and as a result, the polymerization rate And a high degree of polymerization is obtained. Furthermore, in the emulsion polymerization method, since the polymerization process is relatively simple and the polymerization product is fine particles, it is easy to mix with a colorant, a charge control agent, and other additives in the production of a toner. It is advantageous as a method for producing a binder resin for toner as compared with the above method. However, in the emulsion polymerization method, since the emulsifier is added during the polymerization, the produced resin is likely to be impure, and the operation such as salt folding is required to take out the resin, and the operation is complicated. On the other hand, the suspension polymerization method is a simple method and is preferably used.

According to the suspension polymerization method, by polymerizing a monomer mixture containing a low molecular weight polymer or a copolymer in a suspended state together with a crosslinking agent, the resin composition has a pearl-like shape, From the molecular weight polymer or copolymer to the high molecular weight polymer or copolymer containing the cross-linking region component can be obtained in a uniformly mixed and preferable state. When producing the binder resin used in the present invention, when the above-mentioned suspension polymerization method is carried out, 100 parts by weight or less of a monomer, preferably 10 to 9 parts by weight, relative to 100 parts by weight of water or an aqueous solvent.
It is recommended to use 0 part by weight.

As the dispersant usable in the suspension polymerization method, for example, polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate and the like are used. The amount of these dispersants to be used varies depending on the amount of the monomer with respect to the aqueous solvent.
It is used in an amount of 0.05 to 1 part by weight based on parts by weight. or,
The polymerization temperature is appropriately 50 to 95 ° C., but it should be appropriately selected depending on the initiator used and the target polymer. As the polymerization initiator, any of those which are insoluble or hardly soluble in water can be used. For example, benzoyl peroxide, tert-butyl peroxyhexanoate, etc. can be used in an amount of 100% by weight of the monomer. It is used in a proportion of 0.5 to 10 parts by weight with respect to parts.

The following are examples of the vinyl-based resin monomer used when the resin composition used as the binder resin is produced by the above-mentioned polymerization method. For example, styrene: o-methylstyrene, m-
Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene,
3,4-dichlorostyrene, p-ethylstyrene, 2,
4-dimethylstyrene, pn-butylstyrene, p-
Styrene derivatives such as tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene; ethylene, propylene, butylene, Ethylenically unsaturated monoolefins such as isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride; vinyl acetate, vinyl propionate,
Vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, -n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacryl. Methacrylic acid esters such as stearyl acid phenyl, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-acrylate Acrylic esters such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ace Le, vinyl methyl ether, chilled such vinyl ethers vinyl isobutyl ether;
Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone;
Mention may be made of acrylic acid and methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide. These vinyl monomers are used alone or in combination of two or more. Among these, a combination of monomers that can give a styrene-based copolymer, a styrene-acrylic-based copolymer, or a styrene-methacrylic-based copolymer is preferable.

Examples of the monomer containing an acid component that can be used in the present invention include maleic acid, citraconic acid, itaconic acid, alkenylsuccinic acid, fumaric acid,
Unsaturated dibasic acids such as mesaconic acid; maleic anhydride,
Unsaturated dibasic acid anhydrides such as citraconic anhydride, itaconic anhydride, alkenylsuccinic anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester (eg mono-
n-butylmalate), citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, alkenyl succinic acid methyl half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester. Half-esters of saturated dibasic acids; unsaturated dibasic acid diesters such as dimethyl maleic acid and dimethyl fumaric acid.

Further, α, β-unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic anhydride and cinnamic acid anhydride;
An anhydride of the α, β-unsaturated acid and a lower fatty acid; alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides thereof and monoesters thereof can be mentioned. Among these, monoesters of α, β-unsaturated dibasic acids having a structure such as maleic acid, fumaric acid and succinic acid are particularly preferably used.

As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used. To achieve the object of the present invention, the crosslinkable monomer as exemplified below is crosslinked. It is preferably a polymer.

Specifically, for example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene:
As diacrylate compounds linked by an alkyl chain,
Ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate and the above compounds In which acrylate is replaced with methacrylate; diacrylate compounds linked by an alkyl chain containing an ether bond, for example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #
400 diacrylate, polyethylene glycol # 60
0 diacrylate, dipropylene glycol diacrylate and acrylates of the above compounds replaced by methacrylate; diacrylate compounds linked by a chain containing an aromatic group and an ether bond, for example, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate and those obtained by replacing the acrylate of the above compounds with methacrylate Further, polyester type diacrylate compounds, for example, trade name MANDA
(Nippon Kayaku).

As the polyfunctional crosslinking agent, pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate, and acrylates of the above compounds can be used as methacrylate. And the like; triallyl cyanurate, triallyl trimellitate; and the like. These crosslinking agents are preferably used in a proportion of 0.01 to 5 parts by weight (further 0.03 to 3 parts by weight) with respect to 100 parts by weight of the other monomer components.

Among the above-mentioned crosslinkable monomers, aromatic divinyl compounds (particularly divinylbenzene), aromatic groups and ether bonds are preferably used in the toner of the present invention from the viewpoint of fixing property and offset resistance. Examples include chain-containing diacrylate compounds.

Further, in the present invention, reacting the acid component in the binder resin with the metal compound is also one of the preferable modes. As the metal-containing compound capable of reacting with the acid component of the resin composition, those containing the following metal ions can be used. Suitable divalent metal ions include, for example, Ba ²⁺ , Mg ²⁺ , Ca ²⁺ , Hg ²⁺ ,
Examples thereof include Sn ²⁺ , Pb ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ and Zn ²⁺ . Examples of trivalent ions include Al.
³⁺ , Sc ³⁺ , Fe ³⁺ , Ce ³⁺ , Ni ³⁺ , Cr ³⁺ and Y
^{3+ and the} like.

Among the metal compounds, the organometallic compounds are excellent in compatibility and dispersibility with the resin composition, and the crosslinking by the metal compounds progresses more uniformly in the polymer, which is preferable because it gives excellent results. . Furthermore, in the present invention, among the organometallic compounds, those containing an organic compound rich in vaporizability and sublimability as a ligand or a counter ion are useful. Among the organic compounds that form a ligand or counterion with a metal ion, those having the above-mentioned properties include, for example, salicylic acid; salicylamide, salicylamine, salicylaldehyde, salicylosalicylic acid, and ditertiary butylsalicylic acid. Salicylic acid derivatives such as; β-diketones such as acetylacetone and propionacetone; and low molecular weight carboxylic acid salts such as acetate and propionic acid.

When a metal complex is used as the organometallic compound, it can also be used as a charge control agent for toner particles. Examples of such a metal complex include the azo metal complexes represented by the general formula [I] shown below.

[0057]

[Chemical 1]

(In the formula, M is a coordination center metal (for example, Sc, Ti, V, Cr, Co, Ni, Mn and F having a coordination number of 6).
e), Ar represents an aryl group (for example, a phenyl group or a naphthyl group), and may have a substituent. Examples of the substituent in this case include a nitro group, a halogen group, a carboxyl group, an anilide group, an alkyl group having 1 to 18 carbon atoms and an alkoxy group. X, X ', Y and Y'
Are respectively -O-, -CO-, -NH- or -NR- (R
Represents an alkyl group having 1 to 4 carbon atoms),

[Chemical 2] Represents hydrogen, sodium, potassium, ammonium or aliphatic ammonium. )

Specific examples of the metal complex used in the present invention are shown below.

[0060]

Embedded image Complex [I] -1

[0061]

Embedded image Complex [I] -2

[0062]

Embedded image Complex [I] -3

[0063]

Embedded image Complex [I] -4

[0064]

Embedded image Complex [I] -5

[0065]

Embedded image Complex [I] -6

Further, as the organic metal compound, the organic acid metal complex represented by the following general formula [II] also gives a negative charging property, and can be used in the present invention.

[0064]

[Chemical 9] [II] {In the formula, M is a coordination center metal (for example, Cr having a coordination number of 6,
Co, Ni, Mn and Fe). Also, A is

[Chemical 10]

[0067]

[Chemical 11] (X represents a hydrogen atom, an alkyl group, a halogen atom or a nitro group) and

[Chemical 12] (R represents a hydrogen atom or a C _{1 to} C ₁₈ alkyl or alkenyl group). or,

[Chemical 14] Include hydrogen, sodium, potassium, ammonium and aliphatic ammonium. Z is -O- or -C
Indicates OO-. } Next, the specific example of this complex is shown.

Complex [II-1]

[0069]

Embedded image Complex [II-2]

[0070]

Embedded image Complex [II-3]

[0071]

Embedded image Complex [II-4]

[0072]

Embedded image Complex [II-5]

[0073]

Embedded image Complex [II-6] embedded image Complex [II-6] ]

[0074]

Embedded image Complex [II-7]

[0075]

Embedded image Complex [II-8]

[0076]

Embedded image Complex [II-9]

[0077]

Embedded image Complex [II-10]

The metal complex as described above may be used alone or in the form of 2
It is also possible to use a combination of more than one type. The amount of the metal complex added to the toner particles depends on the type of binder resin, whether or not a carrier is used in combination, the type of color pigment of the toner, and the reactivity of the metal complex with the binder resin. The content of the binder, including that of the reaction, is 0.01 to 20% by weight, preferably 0.1 to 10% by weight, based on 100% by weight of the binder.

In the present invention, the metal compound as the cross-linking component can have charge controllability as a toner, but if necessary, a charge control agent can be used separately therefrom. In this case, a conventionally known negative or positive charge control agent is used. Charge control agents known in the art today include: Organometallic complexes and chelate compounds are effective for controlling the toner to be negatively charged. Specifically,
The monoazo metal complex, the acetylacetone metal complex, the aromatic hydroxycarboxylic acid and the aromatic dicarboxylic acid type metal complex as described above can be mentioned. In addition to these, aromatic hydroxycarboxylic acids, metal salts of aromatic mono- and polycarboxylic acids, anhydrides and esters, and phenol derivatives such as bisphenol can also be used.

On the other hand, the following substances can be used to control the toner to be positively charged. For example, modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate and phosphonium salts which are analogs thereof Onium salts and lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as a laking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide and Ferrocyanide, etc.) Further, higher aliphatic metal salts, acetylacetone metal complexes; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, dibutyltin borate,
Diorgano tin borate such as dioctyl tin borate and dicyclohexyl tin borate can also be used. These charge control agents can be used alone or in combination of two or more kinds. Among these charge control agents, nigrosine compounds and quaternary ammonium salts are particularly preferably used.

Further, it is preferable to add silica fine powder to the toner of the present invention in order to improve charge stability, developability, fluidity and durability. The silica fine powder used at this time has a specific surface area of 30 by nitrogen adsorption measured by the BET method.
It is preferably m ² / g or more, more preferably 5
0 to 400 m ² / g. Further, the silica fine powder is 0.01 to 8 parts by weight with respect to 100 parts by weight of the toner,
It is preferable to use 0.1 to 5 parts by weight.

The fine silica powder used in the present invention is
If necessary, for the purpose of hydrophobizing or controlling the chargeability,
For example, it is preferably treated with a treating agent such as a silicone varnish, a modified silicone varnish, a silicone oil, a modified silicone oil, a silane coupling agent, a silane coupling agent having a functional group, and other organosilicon compounds. These treatment agents can be used in combination.

Other additives to be added to the toner of the present invention include, for example, lubricants such as Teflon, zinc stearate and polyvinylidene fluoride (polyvinylidene fluoride being preferred); cerium oxide, silicon carbide and titanium. Abrasives such as strontium acidate (among them strontium titanate is preferred); flowability-imparting agents such as titanium oxide and aluminum oxide (among others, hydrophobic ones are preferred); anti-caking agents; carbon black, zinc oxide, antimony oxide and A conductivity imparting agent such as tin oxide can be used. Further, a small amount of white fine particles or black fine particles having a polarity opposite to that of the toner can be used as a developing property improver.

Further, for the purpose of improving the releasability of the toner at the time of fixing with a heat fixing roller, for example, a wax-like substance such as low-molecular weight polyethylene, low-molecular weight polypropylene, microcrystalline wax, carnauba wax, sazol wax and paraffin wax. It is also one of the preferred embodiments of the present invention to add 0.5 to 10% by weight of the substance to the toner with respect to 100% by weight of the binder resin.

Coloring agents that can be used in the toner of the present invention include any suitable pigments or dyes. Examples of the pigment include carbon black, alinine black,
There are acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, red iron oxide, phthalocyanine blue and indanthrene blue. These pigments can be used in an amount necessary and sufficient for maintaining the optical density of the fixed image, and are 0.1 to 20 parts by weight, preferably 2 to 10 parts by weight, relative to 100 parts by weight of the binder resin. On the other hand, as the dye, for example,
Azo dyes, anthraquinone dyes, xanthene dyes and methine dyes are used. These dyes are 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder resin,
It is preferable to add 0.3 to 10 parts by weight.

The toner of the present invention can also be used as a magnetic toner by containing a magnetic material. In this case, the magnetic material can also serve as a coloring agent. Examples of the magnetic material used include iron oxides such as magnetite, hematite and ferrite; metals such as iron, cobalt and nickel; or these metals and aluminum, cobalt, copper, lead, magnesium, tin and zinc, Antimony,
Included are alloys with metals such as beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten and vanadium, as well as mixtures thereof.

As these magnetic materials, those having an average particle diameter of 0.1 to 2 μm, preferably 0.1 to 0.5 μm are used. The content of the toner is 20 to 200 parts by weight, and particularly preferably 40 to 150 parts by weight, based on 100 parts by weight of the resin component. In addition, the magnetic characteristics under application of 10K oersted are: coercive force 20 to 300 oersted, saturation magnetization 50 to
Those having a residual magnetization of 200 emu / g and a residual magnetization of 2 to 20 emu / g can be preferably used.

The method for producing the toner for developing an electrostatic image according to the present invention includes the binder resin as described above, an organometallic compound such as an organometallic complex or an organometallic complex salt, a colorant, and charge control if necessary. Agents and other additives are thoroughly mixed by a mixer such as a Henschel mixer and a ball mill, and then melt-kneaded by using a heat kneader such as a heating roll, kneader, and extruder, and the resins are made compatible with each other. The organometallic compound and the colorant are uniformly dispersed or dissolved. Further, this is cooled and solidified, and then crushed and classified to be manufactured. The highly crosslinked high molecular weight component can be cut during the melt-kneading in the above step, but this can be favorably carried out by kneading in a low-temperature melted state to give a high share to the kneaded product. Further, the resin composition can be re-crosslinked with a metal-containing compound or the like by heat during melt-kneading. For example, when using an extruder, if the set temperature is set low and a shaft configuration with a high shear is applied, a high shear is applied when passing through the kneading section, the molecular network of the polymer chain is cut, and further discharge is performed. In the meantime, a reaction between the resin composition and the metal compound occurs, and the resin composition is re-crosslinked.

When the toner of the present invention is used as a two-component developer, the toner is mixed with carrier powder.
In this case, the mixing ratio of the toner and the carrier powder is 0.1 to 50% by weight as the toner concentration, preferably 0.5 to
It is 10% by weight, more preferably 3 to 5% by weight. As the carrier used at this time, any conventionally known carrier can be used. Specifically, for example, magnetic powder such as iron powder, ferrite powder and nickel powder, and those whose surface is treated with resin such as fluorine resin, vinyl resin or silicone resin can be mentioned. These carrier powders are further thoroughly mixed with the desired additives together with the toner of the present invention obtained above by a kneader such as a Henschel mixer to obtain a two-component developer.

Next, an image forming method using the toner of the present invention will be described. The toner of the present invention is characterized by being applied to the reuse of untransferred toner (waste toner), that is, an image forming method for forming an image using a toner recycling system. As a specific image forming method for reusing untransferred toner (waste toner) to form an image, after the transfer, the latent image carrier is cleaned to collect the toner on the latent image carrier, and the collected toner is collected. There is a method of recycling the toner by sending it to the developing step for reuse.

FIG. 1 shows an example of an image forming apparatus incorporating a toner recycling system. However, in the drawing, an exposure system, a transport system, a fixing device and the like necessary for image formation are omitted. In the image forming apparatus shown in FIG. 1, first, the surface of the latent image carrier (photosensitive drum) 2 is uniformly charged by corona discharge of the primary charger 1, and then the latent image carrier 2 is exposed by an exposure system (not shown). Image exposure is performed on it to form a latent image. Next, the toner contained in the developing device 3 flies onto the latent image carrier 2 by the developing bias applied to the developing sleeve and the blade, and the latent image is developed to form a toner image. The amount of toner in the developing device 3 is kept constant by consuming toner and replenishing the toner from the toner replenishing hopper 4 as needed. Further, if necessary, the pre-transfer charger 5 removes excess charges on the latent image carrier 2, and then the transfer charger 6 to which a bias is applied transfers the toner image to a transfer material (not shown in the figure). The transfer material is separated from the latent image carrier 2 by the separation charging device 7 to which a bias is applied, and a fixing device (not shown in the figure) performs heat roll fixing to form a fixed image.

On the other hand, after the transfer step is completed, the untransferred toner remaining on the latent image carrier 2 is scraped off by the cleaning blade of the cleaner 8 and collected. The cleaned latent image carrier 2 is used for the next copy. The toner collected by the cleaner 8 is returned to the developing step and reused by the waste toner delivery pipe 9 provided with a conveying screw. In the image forming apparatus shown in FIG. 1, the waste toner is returned to the toner replenishing hopper 4 and reused in the developing process. However, even if the waste toner is directly returned to the developing device 3, it does not matter. No problem.

[0093]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these. All parts in the following formulations are parts by weight.

Synthesis Example 1 (Synthesis of Resin Composition A) -Styrene 65 parts-n-Butyl acrylate 23 parts-Mono-n-butyl maleate 12 parts-Divinylbenzene 1 part-Benzoyl peroxide 0.7 parts Then, 0.5 part of partially saponified polyvinyl alcohol was added to 170 parts of water and vigorously stirred to obtain a suspension dispersion liquid. Further, 30 parts of water was added, and the above suspension dispersion was added to a reaction vessel which had been replaced with nitrogen, and the reaction temperature was 80 ° C
The suspension polymerization reaction was carried out for 8 hours. After completion of the reaction, the polymerization reaction product was washed with water, dehydrated and dried to obtain a resin composition A.

Synthesis Example 2 (Synthesis of Resin Composition B) • Styrene 59.6 parts • 2-Ethylhexyl acrylate 25 parts • Mono-n-butylmalate 15 parts • Divinylbenzene 0.4 parts • Benzoyl peroxide 1.3 parts Di-tert-butylperoxy-2-ethylhexanoate 0.6 part Suspension polymerization was performed in the same manner as in Synthesis Example 1 except that the above materials were used to obtain a resin composition B. .

Synthesis Example 3 (Synthesis of Resin Composition C) Synthesis Example 1 except that mono-n-butyl fumarate was used in place of mono-n-butyl malate and azobisvaleronitrile was used in place of benzoyl peroxide. Suspension polymerization was carried out in the same manner as above to obtain a resin composition C.

Synthesis Example 4 (Synthesis of Resin Composition D) Styrene 78 parts Methyl methacrylate 17 parts Mono-n-butylmalate 5 parts Divinylbenzene 0.5 parts Benzoyl peroxide 1 part The above materials were used. Except for the above, suspension polymerization was carried out in the same manner as in Synthesis Example 1 to obtain a resin composition D.

Comparative Synthesis Example 1 (Synthesis of Resin Composition E) • Styrene 83 parts • n-Butyl acrylate 12 parts • Mono-n-butyl maleate 5 parts • Di-tert-butyl peroxide 7 parts The above materials were heated. It was added dropwise to 200 parts of the above-mentioned toluene over 4 hours. Further, after completing the polymerization under the reflux of toluene, the toluene was removed while the temperature was raised (120 ° C.) under reduced pressure to obtain a resin composition E.

Comparative Synthesis Example 2 (Synthesis of Resin Composition F) Exactly the same as Synthesis Example 1 except that 0.7 part of benzoyl peroxide was replaced with 0.5 part of azobisvaleronitrile and the reaction time was 12 hours. Suspension polymerization by the method
Resin composition F was obtained.

Comparative Synthesis Example 3 (Synthesis of Resin Composition G) -Styrene 76 parts-n-Butyl acrylate 21 parts-Mono-n-butyl maleate 3 parts-Divinylbenzene 0.3 parts-Azobisisobutyronitrile 0. 8 parts Each of the above materials was subjected to solution polymerization in the same manner as in Comparative Synthesis Example 1 to obtain a resin composition G.

Example 1 100 parts of resin composition A, 80 parts of magnetite, 2 parts of Exemplified Complex [II] -1 and 3 parts of low molecular weight polypropylene.
2 parts at 120 ° C after premixing with a Henschel mixer
Melt kneading was performed by a shaft kneading extruder. After the kneaded product is allowed to cool, it is roughly crushed with a cutter mill, then crushed with a fine crusher using a jet stream, and further classified with an air classifier to obtain a black fine powder having a weight average particle diameter of 9.03 μm. (Toner) was obtained. To 100 parts of the above toner, 0.6 part of negatively charged silica fine powder subjected to a hydrophobic treatment was externally added and dry mixed to obtain a developer. GPC measurement was performed on the molecular weight distribution of the resin component of the toner used in this example, and the results are shown in Table 1.

Using the developer obtained above, the toner can be reused and the copying machine NP made by Canon shown in FIG. 1 is used.
An image was formed by a modified machine of 5060 (using an amorphous silicone photoconductor), and the obtained image was evaluated. The result of image evaluation was good, and there was no problem in continuous copying using the toner reuse system. The evaluation results are shown in Tables 2 and 3. Further, after printing 200,000 sheets, the toner consumption was examined using an A4 size document having an image area ratio of 6%.
It was 047 g / sheet.

Example 2 Resin composition B was used instead of resin composition A, except that
Toners were produced in exactly the same manner as in Example 1, and the obtained toners were used to perform the respective evaluations in the same manner as in Example 1. Tables 2 and 3
The results are shown in. Regarding the molecular weight distribution of the resin component of the toner, GPC measurement was performed in the same manner as in Example 1 and the results are shown in Table 1.

Example 3 Except that the resin composition C was used in place of the resin composition A, and the exemplary complex [I] -2 was used in place of the exemplary complex [II] -1, the same as in Example 1. A toner was manufactured in the same manner, and each evaluation was performed in the same manner as in Example 1 using the obtained toner.
The results are shown in Tables 2 and 3. Regarding the molecular weight distribution of the resin component of the toner, GPC measurement was performed in the same manner as in Example 1 and the results are shown in Table 1.

Example 4 A toner was produced in the same manner as in Example 1 except that the resin composition D was used in place of the resin composition A, and the silica was replaced by 2 parts of strontium titanate as an external additive. Then, each evaluation was performed in the same manner as in Example 1 using the obtained toner, and the results are shown in Tables 2 and 3. Regarding the molecular weight distribution of the resin component of the toner, GPC measurement was performed in the same manner as in Example 1 and the results are shown in Table 1.

Example 5 A toner was manufactured in the same manner as in Example 1 except that 5 parts of carbon black, 4 parts of low molecular weight polypropylene were used instead of magnetite, and 1.2 parts of externally added silica was used. Then, each evaluation was performed in the same manner as in Example 1 using the obtained toner. However, when performing image evaluation, a ferrite carrier (particle size of about 80 μm) whose surface is coated with a fluororesin as a carrier is used instead of the developing device for the non-magnetic toner.
Was used and the mixing ratio of the toner to the carrier was 8% by weight. Further, regarding the molecular weight distribution of the resin component of the toner, GPC measurement was performed in the same manner as in Example 1, and the results are shown in Tables 2 and 3. Regarding the molecular weight distribution of the resin component of the toner, GPC measurement was performed in the same manner as in Example 1 and the results are shown in Table 1.

Example 6 Nigrosine and acetylacetonecobalt (II) were used in each of 3 parts in place of Exemplified Complex [II] -1, and negatively chargeable silica was used as an external additive. A toner was manufactured in exactly the same manner as in Example 1 except that the fine silica powder was used, and each evaluation was performed in the same manner as in Example 1 using the toner obtained. The results are shown in Tables 2 and 3. . However, image evaluation was performed by reversal development with NP5060. Further, with respect to the molecular weight distribution of the resin component of the toner, GPC measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 7 The same evaluations as in Example 1 were carried out except that the same toner as in Example 1 was used and the untransferred toner (waste toner) was returned directly into the developing device. The results of this example are shown in Tables 2 and 3, and in all cases, the results were good and not much different from Example 1.

Comparative Example 1 Except that the resin composition E was used in place of the resin composition A,
A toner was manufactured in exactly the same manner as in Example 1, and each evaluation was performed in the same manner as in Example 1 using the obtained toner. The results are shown in Table 2.
And shown in Table 3. Further, with respect to the molecular weight distribution of the resin component of the toner, GPC measurement was performed in the same manner as in Example 1 and the results are shown in Table 1. The resin component of the toner is, as shown in Table 1,
The main peak of GPC was within the range specified in the present invention, but the weight average molecular weight was smaller than the specified value. In addition, from the results of image evaluation, the offset resistance and blocking resistance were particularly deteriorated. Also in the continuous copy test in the reuse system, both the image quality and the image density decreased as the number of evaluated sheets increased. In addition, after passing 200,000 sheets, the toner in the developing device was collected, and the collected waste toner was observed by SEM. As a result, many toner particles were peeled off or split from the inside.

Comparative Example 2 Except that the resin composition F was used in place of the resin composition A,
Toners were manufactured in exactly the same manner as in Example 1, and the obtained toners were used to perform the same evaluations as in Example 1 and the results are shown in Tables 2 and 3. Further, with respect to the molecular weight distribution of the resin component of the toner, GPC measurement was performed in the same manner as in Example 1 and the results are shown in Table 1. With respect to the resin component of the toner used, as shown in Table 1, it was confirmed that the main peak of GPC was larger than the range specified in the present invention. Therefore, as a result of the image evaluation, the fixability and the like were inferior to those in Example 1. Also, in the image evaluation in the reuse system, it was confirmed that the image quality deteriorates as the number of durable sheets advances.

Comparative Example 3 A toner was manufactured in the same manner as in Example 1 except that the resin composition G was used in place of the resin composition A, and the toner obtained was used as in Example 1. Each evaluation was performed in the same manner, and the results are shown in Tables 2 and 3. As for the molecular weight distribution of the resin component of the toner, as in Example 1, the GPC was used.
The measurement was performed and the results are shown in Table 1. The resin component of toner is
As shown in Table 1, it was confirmed that the main peak of GPC was smaller than the specified range specified in the present invention. For this reason, as shown in Table 2, in the image evaluation test, the blocking property and the offset property were particularly deteriorated, and in the continuous copying of the reuse system, the same adverse effects as those in Comparative Example 1 occurred.

Comparative Example 4 An image was prepared by using a developer similar to that used in Example 1 and a system in which untransferred toner (waste toner) was not reused and evaluated. However, the amount of toner consumed was 0.056 g / sheet, which was 19% larger than that in Example 1. The evaluation results are shown in Tables 2 and 3.

The molecular weight distributions of the resin compositions used in the above Examples 1 to 7 and Comparative Examples 1 to 4 were measured by the following method. The results are shown in Table 1. GPC (Waters
High performance liquid chromatograph 150C) manufactured by Showa Denko K.K.
01, 802, 803, 804, 805, 806, 80
A combination of 7,800P was used. The sample concentration was adjusted to 5 mg / ml of resin component and measured.

[0114]

[Table 1] Table 1 Results of measurement of molecular weight distribution of toner resin components in Examples and Comparative Examples

Each evaluation of this example and the comparative example was performed by the following procedure. Fixability The evaluation machine was left overnight in a low temperature and low humidity environment (15 ° C, 10%), and the evaluation machine and the fixing device inside it were completely acclimated to the low humidity and low temperature environment, and 200 copies were continuously made. An image was taken, and the 200th sheet of the copied image was used for evaluation of fixing property. The resulting copy image was rubbed with a sillbon paper under a load of about 100 g 10 times in a reciprocating manner, and the reflection density of the peeling of the image was measured, and the reduction rate (%) was determined and used as the indicator. Offset resistance The cleaning mechanism of the fixing roller was removed, copying was performed, and the number of copies for which the image was soiled or the roller was soiled was evaluated by the number of sheets to be copied. Blocking property About 10 g of toner is put in a 100 cc poly cup and 5
The change in the aggregation degree of the toner when left at 0 ° C. for 1 day was examined. The aggregation degree was measured by a powder tester manufactured by Hosokawa Micron. The indicator of blocking property was the difference in the degree of aggregation between the product left at room temperature and the product left at 50 ° C./day.

[0116]

[Table 2] Table 2 Evaluation results in each Example and Comparative Example

[0117]

[Table 3] Table 3 Evaluation results in each Example and Comparative Example

[0118]

As described above, according to the present invention, it is possible to provide a toner which is excellent in anti-offset property and anti-blocking property and which also gives good results in low-temperature fixing property and developing property. Further, according to the present invention, when used in a system in which waste toner is collected and reused in the developing process, a high reflection image density is maintained from beginning to end even when copying a large number of sheets for a long period of time, and background fog and toner It is possible to provide a toner that gives a copied image without causing scattering. Further, according to the present invention, since the waste toner can be reused and the toner can be effectively used, a high reflection image density can be obtained with a small toner consumption amount, and the space in the copying machine can be simplified. In addition, it is possible to reduce the amount of waste and contribute to the prevention of environmental pollution.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a developing device used for image formation in Examples and Comparative Examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Primary charging device 2 ... Latent image carrier (photosensitive drum) 3 ... Developing device 4 ... Toner replenishing hopper 5 ... Pre-transfer charging device 6 ... Transfer charging device 7 ... Separation charging device 8 ... Cleaner 9 ... Conveying screw Provided waste toner delivery pipe

Claims (1)

[Claims] 1. A latent image bearing member is formed by developing a latent image on a latent image bearing member to form a toner image, transferring the toner image from the latent image bearing member to a transfer material, and then cleaning the latent image bearing member. An electrostatic charge image developing toner used in an image forming method in which untransferred toner on the body is collected, and the collected toner is supplied to the developing unit side and reused in the developing step, which contains at least a binder resin and a colorant. In the toner for developing an electrostatic image, the binder resin component has a main peak in the region of molecular weight of 5,000 to 100,000 in the molecular weight distribution measured by gel permeation chromatography (GPC), and has a weight average molecular weight of 5,000,
A toner for developing an electrostatic charge image, which is a resin of 000 or more.