JP5408932B2 - Image forming method - Google Patents

Description

  The present invention relates to an image forming method used in a recording method represented by electrophotography.

  As electrophotographic technology used in copying machines, printers, facsimile receivers, etc., the demands from users have become stricter year by year as the devices have been developed. In recent years, there is a strong demand to provide stable image quality that does not depend on the environment because it is possible to print a large number of sheets and the environment used by the expansion of the market has expanded. .

  In order to satisfy the above requirements, an image forming method having high durability and high image quality is required more than before, and many improvements have been made to solve the above problems.

  For example, it is known that the inclusion of a fatty acid metal salt in the toner can provide an effect of preventing filming on a cleaning aid or an electrostatic latent image carrier. However, on the other hand, the fatty acid metal salt causes fogging and a decrease in image density, and high image quality cannot be obtained. Therefore, it has been disclosed to improve fogging while improving filming and voiding in an electrostatic latent image carrier by using a fatty acid metal salt and a titanic acid compound in combination (for example, Patent Document 1).

  In addition, by defining the particle size of toner particles having a certain storage modulus or the relationship between the particle size distribution of the toner particles and the particle size and distribution of the fatty acid metal salt, the image quality, fog, and fill to the electrostatic latent image carrier It is disclosed to improve the ming (for example, Patent Documents 2 and 3).

  Further, it is disclosed that fog, toner scattering and toner leakage are suppressed by containing an additive (alumina and titanium oxide) that defines the work function relationship with the base particles and a fatty acid metal salt (for example, Patent Document 4).

  Furthermore, it is disclosed that the image stability can be improved while coating a toner particle with a fatty acid metal salt to suppress the liberation rate while serving as an anti-filming agent for the electrostatic latent image carrier. For example, Patent Document 5).

  Certainly, such measures can reduce fogging, toner scattering, and toner leakage while suppressing toner filming on the latent electrostatic image bearing member, resulting in high durability and high image quality stability. It came to be obtained. However, as a result of intensive studies by the present inventors, the toner described in Patent Documents 1 and 2 has an effect on initial fogging because the particle size of the fatty acid metal salt used is too large. It has been found that there is a problem that when a large number of sheets are printed, the change in chargeability increases and fogging occurs. It has been found that the toners described in Patent Documents 3 and 4 have a problem of fogging due to a decrease in chargeability when the number of printed sheets increases in a severe environment of low temperature and low humidity and high temperature and high humidity.

  Further, in the toner described in Patent Document 5, it is necessary to coat the toner particles with a fatty acid metal salt, and the toner particles are easily mechanically damaged in the coating process, and the toner machine tax member is easily contaminated. It was found that it has the problem.

  Also, a roller charging method has been proposed as a method for charging the electrostatic latent image carrier. In the roller charging method, a conductive elastic roller is brought into pressure contact with a member to be charged, and a voltage is applied to the roller to be discharged to charge the member to be charged. Specifically, the required photosensitive member surface potential Vd at a discharge start voltage (about 550 V when an electrostatic latent image carrier is made to use an OPC photosensitive member and pressurizes the charging roller). There is a DC charging method in which charging is performed by applying a direct-current voltage (DC voltage) to which is added. Furthermore, for the purpose of improving potential fluctuations due to environmental and endurance fluctuations, an alternating current component (AC component) having a peak-to-peak voltage more than twice the discharge start voltage in the DC voltage corresponding to the required photoreceptor surface potential Vd. There is an AC charging method in which charging is performed by applying a voltage superimposed on the contact charging member.

  The DC charging method has an advantage that the power supply cost is generally lower than that of the AC charging method. However, the DC charging method has a narrower discharge area than the AC charging method and does not have a leveling effect with the AC discharge current. Therefore, a horizontal streak-like charging failure (discharge failure image) caused by minute resistance value unevenness of the charging member. ) Is likely to occur. This defect tends to occur particularly in a low humidity environment.

  Therefore, a method has been proposed for improving the horizontal streak-like charging failure by incorporating conductive organic fine particles into the surface layer of the charging member and forming irregularities in the charging member used in the DC charging system ( Patent Document 6).

  In addition, although not in order to improve the said subject, the proposal which uses the particle | grains which have electroconductivity is also made | formed (patent documents 7 thru | or 11).

  However, in the method in which the surface layer of the charging member contains conductive organic fine particles to form irregularities on the surface of the charging member, external additives remaining on the surface of the electrophotographic photosensitive member (charged body) are formed in the recesses. It is easy to deposit, and as a result, the charging ability of the recesses is reduced, and charging unevenness may occur.

  Further, in recent years, there has been a demand for higher image quality of formed images, and as a result, the toner has become smaller in particle size and the proportion of extremely finely divided toner has also increased. Further, the toner has a higher function and various external additives are also used. Therefore, the charging member tends to be further contaminated with an external additive or the like.

  Further, as the life of the electrophotographic image forming apparatus is extended and the color is increased, the durable life of the unit including the charging member and the electrophotographic photosensitive member is extended, and the unit is used for a long time or output in large quantities. As a result, the contact time (contact distance) with the electrophotographic photosensitive member also increases, the amount of deposits increases, and image defects that did not occur with the previous durable sheet may become apparent in the latter half of the durable life. .

  Particularly in a low-humidity environment, image defects (dirt images) such as vertical stripes and spots may occur due to the influence of toner or the like that accumulates on the charging member recesses.

  Further, when conductive fine particles are used, a white spot-like overdischarge image may be generated particularly in a high temperature and high humidity environment.

  That is, in the DC charging method, these problems remain to be solved in achieving high image quality, colorization, and long life.

JP-A-8-272132 Japanese Patent Laid-Open No. 9-311499 JP 2002-296829 A JP 2007-148198 A JP 2007-108622 A JP 2003-316112 A Japanese Patent Laid-Open No. 04-133077 Japanese Patent Laid-Open No. 08-185013 JP 2003-208825 A Japanese Patent Laid-Open No. 2003-223811 JP 2003-162106 A

  In view of the above problems, an object of the present invention is to provide an image forming method excellent in high speed and long life in both low temperature and low humidity and high temperature and high humidity environments.

A first aspect of the present invention for achieving the above object is a charging step of charging an electrostatic latent image carrier with a charging member, and exposing the charged electrostatic latent image carrier to form an electrostatic latent image. In an image forming method comprising an exposure step, a development step of developing the electrostatic latent image with toner, and a transfer step of transferring the toner image to a transfer material with or without an intermediate transfer member,
The surface layer of the charging member is a layer which resin particles are dispersed in the binder resin, the convex portions derived from the resin particles are formed on the surface of the charging member, the ten-point average of the charging member surface The roughness Rzjis is 2 μm or more and 30 μm or less, and the average interval Sm of the irregularities on the surface of the charging member is 7 μm or more and 150 μm or less,
The toner has have a toner particle and the fatty acid metal salt, the median diameter in volume-based of the fatty acid metal salt (D50) is at 0.15μm or 1.00μm or less, free of said fatty acid metal salt in the toner The rate is 1.0% or more and 30.0% or less.

A second invention is characterized in that, in the image forming method, a span value B defined by the following formula (1) of the fatty acid metal salt is 1.75 or less.
Span value B = (D95s−D5s) / D50s (1) Formula D5s: 5% integrated diameter on the volume basis of fatty acid metal salt D50s: Median diameter on the volume basis of fatty acid metal salt D95s: 95% on the volume basis of fatty acid metal salt Integrated diameter

A third invention is characterized in that, in the image forming method, the span value A defined by the following formula (2) of the toner particles and the span value B of the fatty acid metal salt satisfy the following formula (3). .
Span value A = (D90t-D10t) / D50t (2) formula D10t: 10% in the number-based toner particles cumulative diameter D50T: median diameter in number-based toner particles D90t: 90% cumulative diameter in number-based toner particles

0.25 ≦ (A / B) ≦ 0.75 (3) Formula

  According to the present invention, an image forming method with high image quality and long life in high-speed printing can be obtained. That is, according to the present invention, toner filming on the toner carrier, toner regulating member, etc. is suppressed even in high-speed and long-term printing in a low-temperature and low-humidity environment, and further, charging failure of the electrostatic latent image carrier is suppressed. To do. Even in a high-temperature and high-humidity environment, it is possible to obtain an image forming method that suppresses fogging and poor charging.

  The ability to print at high speed for a long period of time, independent of temperature and humidity, is one of the most important issues in meeting market demands. As a result of intensive studies by the present inventors, it is possible to add a fatty acid metal salt having a certain particle diameter to the toner and to regulate the surface roughness of the charging member within a certain range, which is favorable for the above problem. It turns out that the result is obtained.

  Specifically, the surface layer of the charging member includes resin particles dispersed in a binder resin, and convex portions derived from the resin particles are formed on the surface of the charging member. The ten-point average roughness Rzjis is in the range of 2 μm to 30 μm. And the average space | interval Sm of the unevenness | corrugation on the said charging member surface is the range of 7 micrometers or more and 150 micrometers or less. Furthermore, the median diameter (D50) on the volume basis of the fatty acid metal salt is 0.15 μm or more and 1.0 μm or less, and the liberation rate of the fatty acid metal salt is 1.0% or more and 30.0% or less.

  The consideration about the effect expression of this invention is described below.

  As an example, consider an image forming apparatus using non-magnetic one-component toner as shown in FIG. A photosensitive member 21 serving as an electrostatic latent image carrier rotates in the direction of arrow A, is charged by a charging member 22 for charging the photosensitive member 21, and is a laser as an exposure means for writing an electrostatic latent image on the photosensitive member 21. An electrostatic latent image is formed on the surface of the light 23. This electrostatic latent image is developed by applying toner by the developing device 24 and visualized as a toner image.

  The developing device 24 includes a developing container 34 containing a developer 28, and a developing roller 25 as a toner carrying member that is located in an opening extending in the longitudinal direction in the developing container 34 and is opposed to the photosensitive member 21. The electrostatic latent image on the photosensitive member 21 is developed and visualized.

  The developer image on the photosensitive member 21 is transferred to a paper 33 as a transfer material (via an intermediate transfer member when an intermediate transfer member is present) by a transfer roller 29. The paper 33 to which the toner image has been transferred is subjected to a fixing process by the fixing device 32, discharged outside the device, and the printing operation is completed. The toner remaining on the photoreceptor 21 after the transfer is collected by the cleaning blade 30 and stored in the waste developer container 31.

  As described in the above example, the charging process for charging the electrostatic latent image carrier is a very important image forming process, and one of the objects of the present invention is to provide the electrostatic latent image carrier for a long period of time. It is uniformly charged. In other words, the surface layer of the charging member contains resin particles dispersed in the binder resin, and if the convex portions derived from the resin particles are formed on the surface of the charging member, the charging uniformity is improved. To do. The profile of the convex part in this invention can be prescribed | regulated by surface roughness. That is, the condition of the present invention is that the ten-point average roughness Rzjis of the charging member surface is 2 μm or more and 30 μm or less, and the average interval Sm of the irregularities on the charging member surface is 7 μm or more and 150 μm or less.

  The reason why the above-described charging uniformity is increased will be considered. In the charging member having a smooth surface in which the surface layer does not contain resin particles, discharge is only performed in the gaps on both sides of the nip portion with the surface of the electrostatic latent image carrier, and no discharge is observed in the nip. However, it has been found that in the charging member in which the convex portion is formed by the resin particles, in addition to the discharge on both sides of the nip portion with the electrostatic latent image carrier, the discharge is generated in the gap formed in the nip. It is considered that the electric potential on the surface of the electrostatic latent image carrier becomes more uniform due to the discharge in the nip.

  However, if there are irregularities on the surface of the charging member, the concave portions are contaminated with toner or toner-derived substances, and this contamination tends to accumulate, and it is difficult to avoid this. If contaminants accumulate too much in the recesses, the gaps are filled, making it difficult for the discharge in the nip to occur, and the effect of uniform charging is diminished. As described above, the surface roughness condition in which the balance between the suppression of contamination and the improvement of charging uniformity is effective is as follows.

When Rzjis exceeds 30 μm, the surface of the charging member tends to become dirty, and at the same time, the gap is too deep, which may cause discharge failure. If it is smaller than 2 μm, the discharge in the nip hardly occurs, and the charging uniformity which is one of the effects of the present invention is hardly exhibited.
In addition, when the average interval Sm of the surface irregularities is less than 7 μm, the degree of weakening of the charging uniformity effect is large when contaminants accumulate on the surface of the charging member. If it exceeds 150 μm, the charging uniformity effect is reduced.

  As a result of intensive studies by the present inventors, the present inventors have found a toner condition that further maintains the excellent effect of the charging member as described above and further suppresses the occurrence of harmful effects. That is, a toner containing at least toner particles and a fatty acid metal salt, a median diameter (D50) based on volume of the fatty acid metal salt is 0.15 μm or more and 1.00 μm or less, and a liberation rate of the fatty acid metal salt is The toner is 1.0% or more and 30.0% or less. The effect of the toner having this condition in combination with the charging member will be considered below.

  First, when the fatty acid metal salt is contained in the toner, the residual toner cleaning property on the electrostatic latent image carrier is improved. This is a conventionally known technique. By optimizing the D50 and liberation rate of the fatty acid metal salt, it is possible to obtain a large charge uniformity sustaining effect while maintaining such an improvement in cleaning properties. I understood it. As described above, when the charging member surface has irregularities, it is difficult to completely avoid the contamination of the depressions. However, since the toner contains a fatty acid metal salt having a volume-based median diameter (D50) of 0.15 μm or more and 1.00 μm or less, the accumulation rate of contaminants in the recesses is suppressed, and the effect of sustaining charging uniformity is greatly improved. It became clear to do.

  Even when the fatty acid metal salt is contained in the toner, when the D50 of the fatty acid metal salt exceeds 1.00 μm, it was difficult to obtain the effect of suppressing the concave contamination on the surface of the charging member. Therefore, even if the cleaning property is improved by the fatty acid metal salt containing the toner, the conventional concave portion contamination occurs, so that the effect of sustaining the charging uniformity is insufficient. On the other hand, it was found that even if D50 is 0.15 μm or less, the effect of suppressing the concave contamination on the surface of the charging member is diminished.

  Presumably, if D50 exceeds 1.00 μm, it will match the shape of the concave portion profile on the surface, so it will be inferred. The reason why the concave portion contamination is not sufficiently suppressed even when D50 is 0.15 μm or less is not clearly understood, but it is thought that the increase in the adhesion force accompanying the increase in the surface area due to the small median diameter is considered. The above is one of the causes of the effect of sustaining the charging uniformity of the present invention when the toner contains a fatty acid metal salt having a volume-based median diameter (D50) of 0.15 μm or more and 1.00 μm or less.

  Furthermore, there is an effect peculiar to the condition that D50 is 0.15 μm or more and 1.00 μm or less. That is, even if the same amount of contaminants is accumulated in the recess, if the D50 is in the range of 0.15 μm or more and 1.00 μm or less, the discharge inhibition is less than that in the case where it is out of the range. In other words, even if the accumulation of contaminants in the recesses progresses, the timing at which the adverse effects appear will be delayed, and the charging uniformity effect will be further sustained. As described above, the electrostatic latent image bearing member is mainly charged by the discharge from the charging member. The discharge is mainly determined by the conductivity of the charging member and the applied voltage. The reason why the discharge is hindered by the contamination of the concave portion is considered to be that the conductivity of the surface of the charging member does not function due to the contaminant. When the condition that the fatty acid metal salt is 0.15 μm or more and 1.00 μm or less and the roughness profile of the charging member surface is in the range of Rzjis and Sm described above is satisfied, It is likely that a microscopic space is easily generated in the contaminated sediment. That is, the state where the charging member surface and the surface of the electrostatic latent image carrier are not completely buried is maintained microscopically, and the discharge in the nip is maintained. As a result, the charging uniformity is hardly impaired. I guess that.

  The condition that the liberation rate of the fatty acid metal salt is 1.0% or more and 30.0% or less is also a necessary requirement of the present invention. The liberation rate mentioned here refers to the rate of liberation from the toner particles by passing the toner through the mesh. When the adhesion state of the fatty acid metal salt to the toner particles is insufficient, the fatty acid metal salt is easily released when passing through the mesh, and conversely, when the fatty acid metal salt is firmly attached to the toner particles, it is difficult to release (measurement method). Details will be described later).

  When the liberation rate is greater than 25.0%, a large amount of fatty acid metal salt is liberated from the toner, so that the accumulation of contaminants in the recesses is fast. On the other hand, if the liberation rate is less than 1.0%, the liberation of the fatty acid metal salt from the toner particles seems to be very effective, which seems to be effective. However, it has been found that when the liberation rate is less than 1.0%, the concave portion contamination suppressing effect is drastically reduced. In most cases, the main component of the charging member stain is generated by a substance that has passed through the cleaning step of collecting toner remaining on the electrostatic latent image carrier after the transfer step. In many cases, the substances that pass through the cleaning process are dominated by the toner itself or substances released from the toner (such as toner external additives). In particular, toner surface materials represented by free external additives are more dominant. It is difficult to completely eliminate this. In other words, even if the cleaning process slips through the material, it is always present, and the charging member always has an opportunity to come into contact with the slipping material. As described above, it is known that when the D50 of the fatty acid metal salt contained in the toner is 0.15 μm or more and 1.00 μm or less, the surface of the charging member has a concave portion contamination suppressing effect and a charging uniformity sustaining effect. However, if the liberation rate is less than 1.0%, the proportion of fatty acid metal salt contained in the contamination of the charging member contamination that is difficult to avoid decreases, and as a result, the effect of suppressing concave portion contamination and the effect of sustaining charging uniformity are reduced. I suspect that it will end up.

  It has been found that when the toner conditions of the present invention, that is, the D50 and liberation rate of the fatty acid metal salt contained in the toner are in the above range, contamination of the toner carrier and the toner regulating member is effectively suppressed. . Therefore, an excellent image forming method including a developing step can be provided.

In the present invention, when the span value B defined by the following formula (1) of the fatty acid metal salt is 1.75 or less, a greater effect can be obtained.
Span value B = (D95s−D5s) / D50s (1) Formula D5s: 5% integrated diameter D50s of fatty acid metal salt based on volume D: Median diameter of fatty acid metal salt based on volume (D50)
D95s: 95% integrated diameter of fatty acid metal salt based on volume

  A large span value B means that the particle size distribution of the fatty acid metal salt is broad, and a small value means that the particle size distribution of the fatty acid metal salt is sharp. When the span value B exceeds 1.75, the variation in the particle size of the fatty acid metal salt present in the toner increases, and the effect of suppressing the concave contamination on the surface of the charging member is diminished. The span value B is more preferably 1.50 or less, and still more preferably 1.35 or less.

A more preferable condition of the present invention is that the span value A defined by the following formula (2) and the span value B of the toner satisfy the following formula (3).
Span value A = (D90t−D10t) / D50t (2) Expression D10t: 10% integrated diameter based on the number of toners D50t: Median diameter based on the number of toners (D50)
D90t: 90% integrated diameter based on the number of toners

0.25 ≦ (A / B) ≦ 0.75 (3) Formula

  A large span value A means that the particle size distribution of the toner particles is broad, and a small value means that the particle size distribution of the toner particles is sharp. Moreover, it is preferable that ratio (A / B) of span value A and span value B is 0.25 or more and 0.75 or less. In the present invention, the ratio of the span values being in such a range means that the particle size distribution of the fatty acid metal salt is balanced with respect to the particle size distribution of the toner. When the span value ratio A / B is smaller than 0.25, the particle size distribution of the fatty acid metal salt is broad with respect to the particle size distribution of the toner, so that the charge amount of the toner becomes non-uniform. In addition, when A / B is smaller than 0.25, a phenomenon that the substance is easily released from the toner when passing through the cleaning process was observed. This is probably due to the above-described non-uniformity of the toner charge amount. is expected. This is a disadvantageous direction for charging member contamination. On the contrary, the case of exceeding 0.75 means that the particle size distribution of the fatty acid metal salt is too sharp with respect to the particle size distribution of the toner. In this case, there is a tendency that the amount of substances that pass through the cleaning process slightly increases, which is also disadvantageous for charging member contamination. Although the detailed cause is unknown, the presence of a certain particle size distribution in the fatty acid metal salt causes functional separation that affects, for example, cleaning properties and toner charging, with large particles and small particles, and as a result, an appropriate distribution exists. I guess that.

  One of the more preferable conditions of the present invention is that the liberation rate of the fatty acid metal salt is 2.0% or more and 25.0% or less. This further extends the life of the charging member. More preferably, it is 2.0% or more and 20.0% or less.

  It is more preferable that the fatty acid metal salt to be used is fatty acid zinc or fatty acid calcium, since excellent development characteristics can be obtained while maintaining the effect of suppressing contamination of the charging member.

  In order to further enhance the charging member contamination suppressing effect and further improve the excellent development characteristics, the median diameter (D50) of the fatty acid metal salt is 0.30 μm or more and 0.75 μm or less, and the span value B is 1. It is preferable that it is 50 or less.

  Further, the resin particles contained in the surface layer of the charging member surface layer have a volume average particle diameter (Dv) of 1 μm or more and 40 μm or less, which is a preferable condition for enhancing the charging uniformity effect of the present invention. More preferably, the volume average particle diameter (Dv) is 3 μm or more and 30 μm or less.

  It is also a more preferable condition in the present invention that the average interval Sm of the irregularities on the surface of the charging member is 15 μm or more and 120 μm or less. This is a range in which the charging member contamination suppression of the concave portion and the effect of improving the charging uniformity are further enhanced.

  The resin particles contained in the surface layer of the charging member are preferably conductive. By doing so, even if contaminants accumulate in the recesses on the surface of the charging member, the continuity of the discharge in the nip is improved by increasing the number of conductive parts. At this time, the use of resin particles containing carbon black is a more preferable condition for sustaining the in-nip discharge.

  Examples of toner and charging member that can be used in the present invention will be described below. First, the toner will be described.

  The toner particles used in the present invention may be produced by any method, but a production method of granulating in an aqueous medium such as a suspension polymerization method, an emulsion polymerization method, or a suspension granulation method. It is preferable to obtain by.

  Hereinafter, the most preferable suspension polymerization method for obtaining the toner particles used in the present invention will be described as an example to describe the method for producing the toner.

  The binder resin, colorant, wax component and other additives as required are uniformly dissolved or dispersed by a dispersing machine such as a homogenizer, a ball mill, a colloid mill, an ultrasonic dispersing machine, and the polymerization initiator. Is dissolved to prepare a polymerizable monomer composition. Next, toner particles are produced by suspending the polymerizable monomer composition in an aqueous medium containing a dispersion stabilizer and performing polymerization.

  The polymerization initiator may be added simultaneously with the addition of other additives to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  Examples of the binder resin for the toner include commonly used styrene-acrylic copolymers, styrene-methacrylic copolymers, epoxy resins, and styrene-butadiene copolymers. As the polymerizable monomer, a vinyl polymerizable monomer capable of radical polymerization can be used. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

  The following are mentioned as a polymerizable monomer for producing | generating a binder resin. Styrene; Styrenic monomers such as o- (m-, p-) methylstyrene, m- (p-) ethylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, Propyl methacrylate, butyl acrylate, butyl methacrylate, octyl acrylate, octyl methacrylate, dodecyl acrylate, dodecyl methacrylate, stearyl acrylate, stearyl methacrylate, behenyl acrylate, behenyl methacrylate, 2-ethylhexyl acrylate, Acrylic acid ester monomers such as 2-ethylhexyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate and diethylaminoethyl methacrylate, Ether-based monomers; butadiene, isoprene, cyclohexene, acrylonitrile, methacrylonitrile, acrylic acid amide, such as ene-based monomers methacrylamide.

  These polymerizable monomers are used alone or in general, and have a theoretical glass transition temperature (Tg) of 40 to 75 described in Publication Polymer Handbook 2nd edition III-p139-192 (manufactured by John Wiley & Sons). A polymerizable monomer is appropriately mixed and used so as to indicate ° C. If the theoretical glass transition temperature is less than 40 ° C., problems are likely to occur from the viewpoint of storage stability and durability stability of the toner, while if it exceeds 75 ° C., the fixability is lowered.

  In the case of producing toner particles, it is a preferable example to add a low molecular weight polymer so that the THF soluble content of the toner has a preferable molecular weight distribution. The low molecular weight polymer can be added to the polymerizable monomer composition when toner particles are produced by suspension polymerization. The low molecular weight polymer has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) in the range of 2,000 to 5,000, and Mw / Mn of less than 4.5, preferably Those of less than 3.0 are preferred in terms of fixability and developability.

  Examples of the low molecular weight polymer include low molecular weight polystyrene, low molecular weight styrene-acrylic acid ester copolymer, and low molecular weight styrene-acrylic copolymer.

  It is preferable to use together with the above-mentioned binder resin a polar resin having a carboxyl group such as a polyester resin or a polycarbonate resin.

  For example, in the case of directly producing toner particles by a suspension polymerization method, if a polar resin is added from the dispersion step to the polymerization step, the polarities exhibited by the polymerizable monomer composition that becomes the toner particles and the aqueous dispersion medium can be obtained. Depending on the balance, the presence state of the polar resin can be controlled so that the added polar resin forms a thin layer on the surface of the toner particles or exists with a gradient toward the center from the toner particle surface. That is, the addition of the polar resin can reinforce the shell part of the core-shell structure, so that it becomes easy to optimize the micro compression hardness, and the toner of the present invention can achieve both developability and fixability. It becomes easy to do.

  A preferable addition amount of the polar resin is 1 to 25 parts by mass, and more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the binder resin. If the amount is less than 1 part by mass, the presence state of the polar resin in the toner particles tends to be non-uniform. On the other hand, if it exceeds 25 parts by mass, the layer of the polar resin formed on the surface of the toner particles becomes thick.

  Examples of the polar resin include polyester resin, epoxy resin, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and styrene-maleic acid copolymer. A polyester resin is particularly preferable, and the acid value is preferably in the range of 4 to 20 mgKOH / g. When the acid value is less than 4 mgKOH / g, it is difficult to form a shell structure, and the rise of charging is slow, which tends to cause problems such as a decrease in image density and fogging. When the acid value exceeds 20 mgKOH / g, the chargeability is affected and the developability tends to deteriorate. The molecular weight of 3,000 to 30,000 is preferably a main peak molecular weight because the fluidity and negative frictional charging characteristics of the toner particles can be improved.

  In order to increase the mechanical strength of the toner particles and control the molecular weight of the THF soluble component of the toner, a crosslinking agent may be used when the binder resin is synthesized.

  Examples of the bifunctional crosslinking agent include the following. Divinylbenzene, bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6 -Hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 200, # 400, # 600 diacrylate, dipropylene glycol diacrylate, polypropylene Glycol diacrylate, polyester-type diacrylate (MANDA Nippon Kayaku), and diacrylate above instead of diacrylate Thing.

  The following are mentioned as a polyfunctional crosslinking agent. Pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, diallyl phthalate, tri Allyl cyanurate, triallyl isocyanurate and triallyl trimellitate. The addition amount of these crosslinking agents is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  The following are mentioned as a polymerization initiator. 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis Azo or diazo polymerization initiators such as -4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl Peroxide-based polymerization initiators such as peroxide, lauroyl peroxide, tert-butyl-peroxypivalate.

  The amount of these polymerization initiators to be used varies depending on the target degree of polymerization, but is generally 3 to 20 parts by mass with respect to 100 parts by mass of the polymerizable vinyl monomer. The kind of the polymerization initiator varies slightly depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.

  The toner of the present invention contains a colorant as an essential component in order to impart coloring power. Examples of the colorant preferably used in the present invention include the following organic pigments, organic dyes, and inorganic pigments.

  Examples of organic pigments or organic dyes as cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specific examples include the following. C. I. Pigment blue 1, C.I. I. Pigment blue 7, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue.

  Examples of the organic pigment or organic dye as the magenta colorant include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds. Specific examples include the following. C. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment violet 19, C.I. I. Pigment red 23, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 48: 4, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 81: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 169, C.I. I. Pigment red 177, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 220, C.I. I. Pigment red 221, C.I. I. Pigment Red 254.

  Examples of the organic pigment or organic dye as the yellow colorant include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include the following. C. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 62, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 111, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 127, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 168, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 176, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment yellow 191, C.I. I. Pigment Yellow 194.

  Examples of the black colorant include carbon black and those prepared by using the above yellow colorant / magenta colorant / cyan colorant to black.

  These colorants can be used alone or in combination and further in the form of a solid solution. The colorant used in the toner of the present invention is selected from the viewpoints of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in the toner.

  The colorant is preferably used by adding 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer or binder resin.

  When obtaining toner particles using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and water phase transferability of the colorant, and preferably, the colorant is subjected to a hydrophobic treatment with a substance that does not inhibit polymerization. It is better to leave it. In particular, since dye-based colorants and carbon black have many polymerization-inhibiting properties, care must be taken when using them. A preferable method for treating the dye-based colorant includes a method of polymerizing a polymerizable monomer in the presence of these dyes in advance, and the obtained colored polymer is added to the polymerizable monomer composition.

  Moreover, about carbon black, you may process with the substance (for example, polyorganosiloxane etc.) which reacts with the surface functional group of carbon black besides the process similar to the said dye.

  As the dispersion stabilizer used when preparing the aqueous medium, known inorganic and organic dispersion stabilizers can be used.

  Specifically, the following are mentioned as an example of an inorganic dispersion stabilizer. Tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina . Examples of the organic dispersant include the following. Polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, carboxymethyl cellulose sodium salt, starch.

  Commercially available nonionic, anionic and cationic surfactants can also be used. Examples of such surfactants include the following. Sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate.

  As the dispersion stabilizer used at the time of preparing the aqueous medium, an inorganic poorly water-soluble dispersion stabilizer is preferable, and it is preferable to use a poorly water-soluble inorganic dispersion stabilizer that is soluble in an acid.

  Further, when preparing an aqueous medium using a hardly water-soluble inorganic dispersion stabilizer, the amount of these dispersion stabilizers used is 0.2 to 2.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer. It is preferable that In the present invention, it is preferable to prepare an aqueous medium using 300 to 3,000 parts by mass of water with respect to 100 parts by mass of the polymerizable monomer composition.

  When preparing an aqueous medium in which the poorly water-soluble inorganic dispersion stabilizer is dispersed, a commercially available dispersion stabilizer may be used as it is. In order to obtain particles of a dispersion stabilizer having a fine uniform particle size, an aqueous medium may be prepared by generating a poorly water-soluble inorganic dispersion stabilizer in a liquid medium such as water under high-speed stirring. For example, when tricalcium phosphate is used as a dispersion stabilizer, a preferred dispersion stabilizer can be obtained by mixing sodium phosphate aqueous solution and calcium chloride aqueous solution under high speed stirring to form fine particles of tricalcium phosphate. Can do.

  In the toner, if necessary, a charge control agent can be mixed with toner particles and used. By adding a charge control agent, the charge characteristics can be stabilized, and the optimum triboelectric charge amount can be controlled according to the development system.

  As the charge control agent, a known one can be used, and a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable. Further, when the toner particles are produced by a direct polymerization method, a charge control agent having a low polymerization inhibition property and substantially free from a solubilized product in an aqueous medium is particularly preferable.

  Examples of the charge control agent that control the toner to be negatively charged include the following. Organic metal compounds and chelate compounds are effective, and monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acid-based metal compounds. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides, esters, and phenol derivatives such as bisphenol. Further examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, and resin charge control agents.

  Examples of the charge control agent that controls the toner to be positively charged include the following. Nigrosine-modified products such as nigrosine and fatty acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and the like Onium salts such as phosphonium salts and lake pigments thereof; triphenylmethane dyes and lake pigments thereof. Gallic acid, ferricyanide, ferrocyanide, etc.); metal salt of higher fatty acid; resin charge control agent.

  These charge control agents can be contained alone or in combination of two or more.

  Among these charge control agents, a metal-containing salicylic acid-based compound is preferable in order to sufficiently exhibit the effects of the present invention, and the metal is particularly preferably aluminum or zirconium. The most preferred charge control agent is an aluminum 3,5-di-tert-butylsalicylate compound.

  A preferable blending amount of the charge control agent is 0.01 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer or binder resin. However, it is not essential to add a charge control agent to the toner of the present invention, and the toner does not necessarily contain a charge control agent by actively utilizing frictional charging with the toner layer thickness regulating member or the toner carrier. There is no need to let it.

  As a mixer used for the additive mixing step, an existing high-speed stirring mixer such as a Henschel mixer or a super mixer can be used.

  Although the fatty acid metal salt is contained in the toner of the present invention, the preferred range is from 0.02 parts by mass to 0.50 parts by mass with respect to 100 parts by mass of the toner particles.

  Furthermore, other additives may be added. Examples of the additive include fine powder such as silica fine powder, titanium oxide fine powder, or double oxide fine powder thereof. Among the inorganic fine powders, silica fine powder and titanium oxide fine powder are preferable.

Examples of the silica fine powder include dry silica or fumed silica produced by vapor phase oxidation of silicon halide, and wet silica produced from water glass. As the inorganic fine powder, dry silica having less silanol groups on the surface and inside the silica fine powder and less Na ₂ O and SO ₃ ²⁻ is preferable. The dry silica may be a composite fine powder of silica and another metal oxide by using a metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound in the production process.

  The inorganic fine powder is added to the toner particles in order to improve the fluidity of the toner and make the toner particles uniformly charged. By hydrophobizing the inorganic fine powder, it is possible to adjust the charge amount of the toner, improve the environmental stability, and improve the characteristics in a high-humidity environment. It is preferable to use it. When the inorganic fine powder added to the toner absorbs moisture, the charge amount as the toner is reduced, and the developability and transferability are easily lowered.

  Treatment agents for hydrophobizing inorganic fine powder include unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, organic A titanium compound is mentioned. These treatment agents may be used alone or in combination.

  Among these, inorganic fine powder treated with silicone oil is preferable. More preferably, when the inorganic fine powder is hydrophobized with a coupling agent or simultaneously with or after the treatment, the hydrophobized inorganic fine powder treated with silicone oil maintains a high toner particle charge amount even in a high humidity environment, and is selected. It is good for reducing developability.

  The total amount of the inorganic fine powder is preferably 1.5 to 5.0 parts by mass with respect to 100 parts by mass of the toner particles. In addition, the fatty acid metal salt of the present invention is preferably contained in a ratio of 0.02 parts by mass or more and 0.50 parts by mass or less with respect to 100 parts by mass of the toner base particles.

  Next, examples of the charging member in the present invention will be described.

  The conductive support used for the charging member of the present invention is, for example, a cylinder having a carbon steel alloy surface plated with nickel having a thickness of 5 μm. Other materials constituting the conductive support include metals such as iron, aluminum, titanium, copper and nickel; alloys such as stainless steel, duralumin, brass and bronze containing these metals; carbon black and carbon fibers made of plastic Hardened composite materials can be used. Moreover, a well-known material which is rigid and shows electroconductivity can also be used. In addition to the columnar shape, the shape may be a cylindrical shape having a hollow central portion, a plate shape, or a belt shape.

  The surface layer of the charging member of the present invention contains a resin particle having at least conductivity in a binder resin.

  As the binder resin used for the surface layer of the charging member of the present invention, resins such as thermosetting resins and thermoplastic resins are used. Specifically, urethane resins, fluorine resins, silicone resins, acrylic resins, polyamides are used. Resin.

  In the present invention, the binder resin is preferably a urethane resin, and particularly preferably a urethane resin crosslinked with an isocyanate compound using a lactone-modified acrylic polyol.

  The isocyanate compound used here is more preferably an isocyanurate type trimer. The rigid trimer of the molecule serves as a cross-linking point, the surface layer can be cross-linked more closely, and it is possible to more effectively prevent the low molecular component from seeping out from the conductive elastic layer to the roller surface. it can. The isocyanate compound is more preferably a blocked isocyanate in which an isocyanate group is blocked with a blocking agent. The reason for this is that isocyanate groups are easy to react, and if the coating material for surface layer coating is left at room temperature for a long time, the reaction gradually proceeds and the properties of the coating material may change. On the other hand, in the blocked isocyanate, active isocyanate groups are blocked, and the block bond does not dissociate up to the dissociation temperature, so that there is an advantage that handling of the paint becomes easy. Examples of the blocking agent for this purpose include phenols such as phenol and cresol, lactams such as ε-caprolactam, and oximes such as methyl ethyl ketoxime. In the present invention, oximes having a relatively low dissociation temperature are preferred.

  A leveling agent may be mixed in the resin paint forming the surface layer. Examples of the leveling agent include silicone oil.

  In the charging member of the present invention, at least resin particles are blended in a binder resin. Examples of the resin used for the resin particles include PMMA, acrylic resin, polybutadiene resin, polystyrene resin, polyethylene, polypropylene, polybutadiene or the like, or a copolymer thereof, benzoguanamine resin, phenol resin, polyamide resin, nylon, fluorine resin, silicone Resins, epoxy resins, polyester resins and the like can be mentioned.

  The resin particles preferably have a ratio of particles having a circularity of 0.9 or more of 80% or more. If the resin particles are separated from the perfect circle, the flow of charges flowing through the surface layer becomes non-uniform, and there may be a portion where charges are concentrated.

  In the present invention, the resin particles preferably have conductivity, and in order to obtain the conductivity, it is preferable to contain carbon black having an average particle diameter of 10 nm to 300 nm.

  Examples of the carbon black include carbon powder such as furnace black, thermal black, acetylene black, PAN (polyacrylonitrile) -based carbon, and pitch-based carbon.

  The resin particles preferably have a volume average particle diameter (Dv) of 1 μm or more and 40 μm or less, which is a preferable condition for enhancing the charging uniformity effect, and more preferably, the volume average particle diameter (Dv) of 3 μm or more and 30 μm or less. It is.

  The volume average particle diameter (Dv) of the resin particles in the surface layer is calculated as follows. An arbitrary point on the surface layer is cut out with a focused ion beam “FB-2000C” (trade name, manufactured by Hitachi, Ltd.) every 20 nm over 500 μm, and a cross-sectional image thereof is taken. And the image which image | photographed the same resin particle is combined by 20 nm space | interval, and a three-dimensional particle shape is calculated. This operation is performed at an arbitrary 100 points on the surface layer of the charging member.

  For the average particle diameter of the resin particles, the projected area is calculated from the three-dimensional particle shape obtained above, and the equivalent circle diameter of the obtained area is calculated. A volume average particle diameter (Dv) is determined from the equivalent circle diameter.

  For the average particle size of the carbon black included in the resin particles, 100 arbitrary carbon black particles are selected from a cross-sectional image obtained by photographing the resin particles. Then, the projected area of the carbon black particles is obtained, the equivalent circle diameter of the obtained area is calculated to obtain the volume average particle diameter, and this can be obtained as the average particle diameter of the carbon black particles. At this time, only particles having an equivalent circle diameter in the range of 5 nm to 500 nm were measured as measurement objects.

The conductivity of the resin particles in the present invention refers to resin particles having a volume resistivity of 1 × 10 ¹⁰ Ω · cm or less. A preferable range is 1 × 10 ² Ω · cm or more and 1 × 10 ⁹ Ω · cm or less.

The volume resistivity of the resin particles is determined by leaving the particles themselves in a 23 ° C./50% RH environment for 12 hours or longer and using a resistance measuring device “Loresta-GP” (trade name, manufactured by Mitsubishi Chemical Corporation) according to the attached manual. The measured value when a voltage of 10 V is applied to the sample. In addition, as a sample to be measured, a sample compressed by applying a pressure of 10.1 MPa (102 kgf / cm ² ) is used.

  The content of the resin particles is preferably 2 parts by mass or more and 120 parts by mass or less, more preferably 5 parts by mass or more and 100 parts by mass or less, and still more preferably 5 parts by mass or more and 80 parts by mass with respect to 100 parts by mass of the binder resin. More effects can be achieved in the range of less than or equal to the part.

  The film thickness of the surface layer is preferably (Dv) / 3 times or more and 10 × (Dv) or less, more preferably (Dv) with respect to the volume average particle diameter (Dv) of the resin particles used as a roughening agent. / 2 to 5 × (Dv). If the surface layer is too thick compared to the particle size of the resin particles, the resin particles are buried in the film and it is difficult to form convex portions derived from the resin particles on the surface of the charging member. On the other hand, if it is too thin, resin particles may be lost due to contact with the photoconductor or rubbing.

  In the case of a roller-shaped charging member, the surface layer has a film thickness of 3 locations in the axial direction and 3 locations in the circumferential direction. It can be observed and measured with an electron microscope, and the average value is taken as the film thickness of the surface layer of the charging member. In the belt-like or plate-like charging member, nine portions where the surface layer is dispersed are cut out in the same manner as described above, and the film thickness is measured.

  The surface roughness (Rzjis and Sm) of the charging member was determined based on JIS B0601-2001 by using a surface roughness meter “Surf Coder SE3400” (trade name, manufactured by Kosaka Laboratories Co., Ltd.) in three axial directions. Measure a total of 6 places, 2 places in the circumferential direction, and use the average value. In the present specification, the contact needle is a diamond having a tip radius of 2 μm, the measurement speed is 0.5 mm / s, the cutoff λc is 0.8 mm, the reference length is 0.8 mm, and the evaluation length is 8.0 mm. .

  In addition, the resistance of the surface layer of the charging member can be adjusted by using a conductive agent such as an ionic conductive agent or an electronic conductive agent together with the resin particles.

  The ionic conductive agent is not particularly limited as long as it is an ionic conductive agent exhibiting ionic conductivity. Examples of ionic conductive agents include inorganic ionic substances such as lithium perchlorate, sodium perchlorate, and calcium perchlorate; lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethyl Cationic surfactants such as ammonium chloride, trioctylpropylammonium bromide, modified aliphatic dimethylethylammonium ethosulphate; zwitterionic surfactants such as lauryl betaine, stearyl betaine, dimethylalkyl lauryl betaine; tetraethyl perchlorate Such as ammonium, tetrabutylammonium perchlorate, trimethyloctadecylammonium perchlorate Grade ammonium salt; and organic acid lithium salts such as lithium trifluoromethanesulfonate can be used. Among them, quaternary ammonium perchlorate is particularly preferable because of its resistance to environmental changes.

  The electronic conductive agent is not particularly limited as long as it is an electronic conductive agent exhibiting electronic conductivity. Electronic conductive agents include metal-based particles and fibers such as aluminum, palladium, iron, copper, and silver; metal oxides such as titanium oxide, tin oxide, and zinc oxide; Electrolytic treatment, spray coating, mixed shaking of conductive metals and metal oxides such as antimony, indium oxide, molybdenum oxide, zinc, aluminum, gold, silver, copper, chromium, cobalt, iron, lead, platinum, rhodium For example, carbon particles such as furnace black, thermal black, acetylene black, ketjen black (trade name), PAN (polyacrylonitrile) carbon, and pitch carbon can be used. As the furnace black and the thermal black, those described above can be used without any problem.

  These conductive agents may be used alone or in combination of two or more. In addition, when using a electrically conductive agent for a surface layer, the thing which is hard to be influenced by external factors, such as an environment, is preferable, Therefore, generally an electronic electrically conductive agent is used.

  The conductive agent is preferably conductive fine particles having an average particle size of 0.01 μm to 0.9 μm, preferably 0.01 μm to 0.5 μm.

  In the present invention, a conductive support and a surface layer are essential, but in order to improve the function as a charging member between the conductive support and the surface layer, at least one conductive elastic layer is provided. Is preferred. In addition to the conductive elastic layer, a resistance layer or the like may be provided. Further, the surface of each layer provided on the conductive support may be subjected to various treatments, and the conductive support is bonded to directly adhere to the layer to be controlled. An agent may be applied in advance.

  The conductive elastic layer is made of a conductive elastic body, and the conductive elastic body is composed of at least a conductive agent and a polymer elastic body.

  Polymer elastic bodies include epichlorohydrin rubber, NBR (nitrile rubber), chloroprene rubber, urethane rubber, silicone rubber, SBS (styrene / butadiene / styrene / block copolymer), SEBS (styrene / ethylene butylene / styrene block). A thermoplastic elastomer such as a copolymer is suitable. In addition, as a polymer elastic body, epichlorohydrin rubber has the conductivity of the medium resistance region of the polymer itself, and can exhibit good conductivity even if the addition amount of the conductive agent is small, and the electric resistance depending on the position. Therefore, it is preferable to use it.

  Examples of the epichlorohydrin rubber include epichlorohydrin (EP) homopolymer, EP-ethylene oxide (EO) copolymer, EP-allyl glycidyl ether (AGE) copolymer, and EP-EO-AGE terpolymer. Among these, an EP-EO-AGE terpolymer is particularly preferable because it exhibits stable conductivity in a medium resistance region. Note that the EP-EO-AGE terpolymer can control conductivity and workability by arbitrarily adjusting the degree of polymerization and the composition ratio. When epichlorohydrin rubber is used as a main component, other general rubber is appropriately blended as necessary.

  Other common rubbers include EPM (ethylene propylene rubber), EPDM (ethylene propylene rubber), NBR, chloroprene rubber, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, urethane rubber, silicone rubber, etc. Can be used. Moreover, you may use thermoplastic elastomers, such as SBS and SEBS. When the above general rubber is blended, the content is preferably 1% by mass to 50% by mass with respect to the total amount of the polymer elastic body.

  As the conductive agent, an ionic conductive agent or an electronic conductive agent can be used. For the purpose of reducing the unevenness of electric resistance of the conductive elastic layer, it is preferable to contain an ionic conductive agent. The ionic conductive agent is easily dispersed uniformly in the polymer elastic body, the electric resistance of the conductive elastic body becomes uniform, and uniform charging can be obtained even when only a DC voltage is applied to the charging member.

  The ionic conductive agent is not particularly limited as long as it is an ionic conductive agent exhibiting ionic conductivity. What can be used for the said surface layer as an ionic conductive agent can be used without trouble. Among ionic conductive agents, quaternary ammonium perchlorate is particularly preferred because of its resistance to environmental changes.

  The electronic conductive agent is not particularly limited as long as it is an electronic conductive agent exhibiting electronic conductivity. What can be used for the said surface layer as an electronic electrically conductive agent can be used without trouble.

  Moreover, these electrically conductive agents may be used independently or may be used in combination of 2 or more types.

  A compounding agent such as a plasticizer, a filler, a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a scorch preventing agent, a dispersing agent, and a release agent may be added to the conductive elastic body as necessary. .

  As a method of forming a conductive elastic body on a conductive support, the above-mentioned raw material composition of the conductive elastic body is mixed with a closed mixer, and known methods such as extrusion molding, injection molding, compression molding, etc. It is preferable to use this molding method. The conductive elastic layer may be provided directly on the conductive support, or when the charging member is a charging roller, a tube-shaped conductive elastic body formed in advance is coated on the conductive support. May be. When the charging roller is manufactured, it is also preferable that the conductive elastic layer is formed and then the surface is polished to prepare the shape.

  In the charging roller, the shape of the conductive elastic layer is formed in a crown shape in which the central portion is thickest and narrows toward both ends in order to ensure uniform adhesion with the electrostatic latent image carrier. It is preferable. Since the charging roller generally used is in contact with the photosensitive member 4 by applying a predetermined pressing force to both ends of the support, the pressing force at the center is small and the both ends are large. Therefore, the charging roller has no problem if the straightness is sufficient and the rigidity of the support is sufficient, but if these are not sufficient, density unevenness may occur in the images corresponding to the center and both ends. There is. The crown shape is effective to prevent this.

  Further, when the charging roller is rotated in contact with the electrostatic latent image carrier, the nip width becomes uniform, and therefore it is desirable that the roller has a small outer diameter difference when the conductive elastic layer is provided. .

  The hardness of the conductive elastic body is preferably a micro hardness of 70 ° or less, more preferably 60 ° or less. When the micro hardness exceeds 70 °, the contact between the charging member and the photosensitive member tends to be unsuitable, and particularly in the charging roller, the nip width becomes small, and the contact force between the charging member and the photosensitive member becomes a narrow area. Concentrate and increase the contact pressure. This may cause adverse effects such as charging becoming unstable or developer or the like being easily attached to the surface of the electrostatic latent image carrier or the charging member.

  In addition, "micro hardness" is the hardness of the rubber member measured using the micro area | region rubber hardness meter "Asker micro rubber hardness meter MD-1 type" (brand name, the polymer instrument company make). . In the present invention, for the charging member left in a 23 ° C./55% RH (NN) environment for 12 hours or more, the hardness meter is a value measured in a 10 N peak hold mode.

  A plasticizer may be arranged on the conductive elastic body for the purpose of reducing the micro hardness. The blending amount is preferably 1 part by mass or more and 30 parts by mass or less, and more preferably 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the highly divided elastic body. As the plasticizer, it is preferable to use a polymer type. The polymer plasticizer has a number average molecular weight of preferably 2000 or more, more preferably 4000 or more. If the molecular weight is less than 2000, the plasticizer may ooze out on the surface of the roller and contaminate the electrostatic latent image carrier, and if it is 4000 or more, the effect of softening the conductive elasticity may not be obtained.

  The conductive elastic layer is bonded to the conductive support through an adhesive as necessary. In this case, the adhesive is preferably conductive. In order to make it conductive, the adhesive may have a known conductive agent.

  Examples of the binder of the adhesive include thermosetting resins and thermoplastic resins, and known ones such as urethane, acrylic, polyester, polyether, and epoxy can be used.

  As a conductive agent for imparting conductivity to the adhesive, it can be appropriately selected from the above-mentioned conductive agents, and can be used alone or in combination of two or more.

  In general, after a conductive elastic layer is produced, a surface layer is provided as a covering layer.

  As a method for forming the surface layer, the material constituting the surface layer is used as a paint, and the paint is applied on a conductive substrate by dipping, spray coating, roll coating, ring coating, or the like. To do. The coating material can be obtained by dispersing various materials for the surface layer in a solvent by a known method using a conventionally known dispersing device using beads such as a sand mill, a paint shaker, a dyno mill, and a pearl mill.

  The thickness of the surface layer can be adjusted by controlling the solid content of the surface layer coating material, the coating speed, and the like. For example, when the surface layer of the charging roller is formed by the dip method, the film thickness of the surface layer increases as the solid content of the resin in the paint increases, and the film thickness decreases as the solid content decreases. The surface layer coating material adjusts the solid content to 10% by mass to 40% by mass with respect to the solvent to be volatilized. Further, when the coating pulling speed is increased, the film thickness is increased, and when the coating pulling speed is decreased, the film thickness is decreased. Therefore, it is appropriate to perform the coating pulling speed within a range of 20 mm / min to 5000 mm / min.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples as long as the gist thereof is not exceeded.

  The physical properties relating to the fatty acid metal salt and toner in the present invention were measured using the following methods.

<Measurement of median diameter (D50) and span value B of fatty acid metal salt>
The volume-based median diameter (D50) of the fatty acid metal salt used in the present invention is measured according to JIS Z8825-2 (2001), and is specifically as follows.

  As a measuring device, a laser diffraction / scattering particle size distribution measuring device “LA-920” (manufactured by Horiba, Ltd.) is used. The dedicated software “HORIBA LA-920 for Windows (registered trademark) WET (LA-920) Ver. 2.02” attached to LA-920 is used for setting measurement conditions and analyzing measurement data. As the measurement solvent, ion-exchanged water from which impure solids are removed in advance is used.

  The measurement procedure is as follows.

  (1) A batch type cell holder is attached to LA-920.

  (2) A predetermined amount of ion-exchanged water is put into a batch type cell, and the batch type cell is set in a batch type cell holder.

  (3) The inside of the batch cell is stirred using a dedicated stirrer chip.

  (4) Press the “refractive index” button on the “display condition setting” screen and select the file “110A000I” (relative refractive index 1.10).

  (5) In the “display condition setting” screen, the particle diameter reference is set as the volume reference.

  (6) After performing warm-up operation for 1 hour or more, the optical axis is adjusted, the optical axis is finely adjusted, and blank measurement is performed.

  (7) Put about 60 ml of ion-exchanged water in a glass 100 ml flat bottom beaker. Among them, as a dispersant, “Contaminone N” (a nonionic surfactant, an anionic surfactant, a 10% by weight aqueous solution of a neutral detergent for washing a pH 7 precision measuring instrument comprising an organic builder, Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting the product (manufactured) with ion exchange water about 3 times by mass is added.

  (8) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.

  (9) The beaker of (7) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the aqueous solution in a beaker may become the maximum.

  (10) In a state where the aqueous solution in the beaker of (9) is irradiated with ultrasonic waves, about 1 mg of a fatty acid metal salt is added to the aqueous solution in the beaker little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In this case, the fatty acid metal salt may solidify and float on the liquid surface. In this case, ultrasonic dispersion is performed for 60 seconds after the mass is submerged by shaking the beaker. Moreover, in ultrasonic dispersion, it adjusts suitably so that the water temperature of a water tank may become 10 to 40 degreeC.

  (11) The aqueous solution in which the fatty acid metal salt prepared in the above (10) is dispersed is immediately added little by little to a batch type cell, taking care not to enter bubbles, and the transmittance of the tungsten lamp is 90% to 95%. Adjust so that Then, the particle size distribution is measured. Based on the obtained volume-based particle size distribution data, a median diameter (D50), a 5% integrated diameter, and a 95% integrated diameter are calculated to obtain a span value B.

<Rate of fatty acid metal salt>
The liberation rate of the fatty acid metal salt in the toner according to the present invention is determined by measuring a powder tester (manufactured by Hosokawa Micron Co., Ltd.) having a digital vibrometer (Digivibro Model 1332), an X-ray fluorescence analyzer Axios (manufactured by PANallytical), and setting and measuring measurement conditions. The liberation rate of the fatty acid metal salt was determined from the intensity difference of fluorescent X-rays using the attached dedicated software “SuperQ ver. 4.0F” (manufactured by PANalytical) for data analysis.

  As a specific measuring method, a sieve having a mesh size of 25 μm (635 mesh) is set on a vibrating table of a powder tester. 5 g of a sample accurately weighed is added to the sieve having a mesh size of 25 μm (635 mesh), the amplitude of the digital vibrometer is adjusted to about 0.60 mm, and vibration is applied for about 2 minutes. The above operation is further repeated twice, and the sample is passed through a 25 μm (635 mesh) sieve three times in total. Next, about 4 g of the obtained sample is placed on an aluminum ring having a diameter of 40 mm, and compressed by a press machine at 150 kN to prepare a sample. The obtained sample was measured with a fluorescent X-ray analyzer (Axios). Rh is used as the anode of the X-ray tube, the measurement atmosphere is vacuum, the measurement diameter (collimator mask diameter) is 27 mm, and the measurement time is 10 seconds. Further, when measuring a light element, it is detected by a proportional counter (PC), and when measuring a heavy element, it is detected by a scintillation counter (SC).

The liberation rate of the fatty acid metal salt was determined from the following formula by measuring the Kα ray net intensity (KCPS) of the metal element of the fatty acid metal salt before and after the sieve.
{(Kα ray net intensity of metal element of fatty acid metal salt in toner before sieve) − (Kα ray net intensity of metal element of fatty acid metal salt in toner passed through sieve)} / (Fatty acid metal in toner before sieve) Kα line net intensity of salt metal elements)

<Measurement of Toner Number-Based Median Diameter (D50) and Span Value A>
The median diameter (D50) based on the number of toners is calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. Note that the measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, dedicated software was set up as follows.

  On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

  The specific measurement method is as follows.

  (1) About 200 ml of the electrolytic aqueous solution is put in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rotations / second. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.

  (2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.

  (3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. A predetermined amount of ion-exchanged water is placed in a water tank of an ultrasonic disperser, and about 2 ml of the contamination N is added to the water tank.

  (4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.

  (5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.

  (6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.

(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the number-based median diameter (D50) and span value A are calculated. Note that “d ₅₀ ” on the “analysis / number statistical value (arithmetic mean)” screen when the graph / number% is set in the dedicated software is the median diameter (D50). In addition, “d ₁₀ ” in the “analysis / count statistics (arithmetic mean)” screen is an integrated 10% diameter, and “d ₉₀ ” is an integrated 90% diameter. The span value A can be calculated from the obtained D10t, D50t, and D90t.

<Manufacture of toner particles 1>
With respect to 100 parts by mass of the styrene monomer, C.I. I. 16.5 parts by mass of Pigment Blue 15: 3 and 2.0 parts by mass of an aluminum compound of 3,5-di-tert-butylsalicylic acid [Bontron E88 (manufactured by Orient Chemical Co., Ltd.)] were prepared. These were introduced into an attritor (manufactured by Mitsui Mining Co., Ltd.) and stirred at 200 rpm at 25 ° C. for 180 minutes using zirconia beads (140 parts by mass) with a radius of 1.25 mm to prepare a master batch dispersion 1. .

On the other hand, 450 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution was added to 710 parts by mass of ion-exchanged water and heated to 60 ° C., and then 68 parts by mass of 1.0 M CaCl ₂ aqueous solution was gradually added to the calcium phosphate compound. An aqueous medium containing was obtained.

Master batch dispersion 1 40 parts by mass Styrene monomer 30 parts by mass n-butyl acrylate monomer 18 parts by mass Low molecular weight polystyrene 20 parts by mass (Mw = 3,000, Mn = 1,050, Tg = 55 ° C)
Hydrocarbon wax 9 parts by mass (Fischer-Tropsch wax, maximum endothermic peak = 78 ° C., Mw = 750)
Polyester resin 5 parts by mass (terephthalic acid: isophthalic acid: propylene oxide modified bisphenol A (2 mol adduct): ethylene oxide modified bisphenol A (2 mol adduct) = 30: 30: 30: 10 polycondensate, acid No. 11, Tg = 74 ° C., Mw = 11,000, Mn = 4,000)
The above material was heated to 65 ° C., and uniformly dissolved and dispersed at 5,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). In this, 7.0 parts by mass of a 70% toluene solution of a polymerization initiator 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate was dissolved to prepare a polymerizable monomer composition.

The polymerizable monomer composition is charged into the aqueous medium, and stirred at 10,000 rpm for 10 minutes with a TK homomixer in a N ₂ atmosphere at a temperature of 65 ° C. to prepare a polymerizable monomer composition. Then, the temperature was raised to 67 ° C. while stirring with a paddle stirring blade, and when the polymerization conversion of the polymerizable vinyl monomer reached 90%, a 0.1 mol / liter sodium hydroxide aqueous solution was added. The pH of the aqueous dispersion medium was adjusted to 9 by addition. Furthermore, it heated up at 80 degreeC with the temperature increase rate of 40 degreeC / h, and was made to react for 4 hours. After completion of the polymerization reaction, the residual monomer in the toner particles was distilled off under reduced pressure. After cooling the aqueous medium, hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 6 hours to dissolve the calcium phosphate salt. The toner particles were separated by filtration, washed with water, and then dried at a temperature of 40 ° C. for 48 hours to obtain cyan toner particles (1). Table 1 shows the physical properties of the obtained toner particles.

<Manufacture of toner particles 2>
In the production of toner particles 1, the stirring at 10,000 rpm with a TK homomixer for 10 minutes was changed to the stirring at 8,000 rpm for 10 minutes, and the rest was the same as in the production of toner particles 1, Toner particles 2 were obtained. The physical properties of the obtained toner particles 2 are shown in Table 1.

<Manufacture of toner particles 3>
The following materials were mixed in advance, melt kneaded with a biaxial extruder, the cooled kneaded product was coarsely pulverized with a hammer mill, and the resulting finely pulverized product was classified to obtain toner particles 3.
Binder resin 100 parts by mass [styrene-n-butyl acrylate copolymer resin (Mw = 30,000, Tg = 62 ° C.)]
・ C. I. Pigment Blue 15:35 parts by mass, aluminum compound of di-tertiary butylsalicylic acid 3 parts by mass [Orient Chemical Industries, Ltd .: Bontron E88]
Ester wax 6.0 parts by mass (behenyl behenate: maximum endothermic peak = 72 ° C., Mw = 700)

  The physical properties of the obtained toner particles 3 are shown in Table 1.

<Manufacture of toner particles 4>
Emulsion polymerization method--Preparation of resin particle dispersion 1--
-Styrene 75 parts by mass-n-Butyl acrylate 25 parts by mass-Acrylic acid 3 parts by mass Mixing and dissolving the above, 1.5 parts by mass of a nonionic surfactant (manufactured by Sanyo Chemical Co., Ltd .: Nonipol 400) And an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 2.2 parts by mass dissolved in 120 parts by mass of ion-exchanged water, dispersed, emulsified, and slowly mixed for 10 minutes, To this was added 10 parts by mass of ion-exchanged water in which 1.5 parts by mass of ammonium persulfate had been dissolved, and after nitrogen substitution, the contents were heated with stirring until the contents reached 70 ° C., and the emulsion polymerization was continued for 4 hours. Then, a resin particle dispersion 1 in which resin particles having an average particle diameter of 0.29 μm are dispersed was prepared.

--Preparation of resin particle dispersion 2--
-Styrene 40 parts by mass-n-butyl acrylate 58 parts by mass-Divinylbenzene 0.3 part by mass-Acrylic acid 3 parts by mass A mixture of the above and dissolved is a nonionic surfactant (manufactured by Sanyo Chemical Co., Ltd .: Nonipol 400) 1.5 parts by mass and anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 2.2 parts by mass were dissolved in 120 parts by mass of ion-exchanged water, dispersed and emulsified. While slowly mixing for 10 minutes, 10 parts by mass of ion-exchanged water in which 0.9 part by mass of ammonium persulfate was dissolved was added thereto, and after nitrogen substitution, the contents were heated to 70 ° C. with stirring. Emulsion polymerization was continued as it was for 4 hours to prepare a resin particle dispersion 2 in which resin particles having an average particle size of 0.31 μm were dispersed.

-Preparation of colorant particle dispersion 1-
・ C. I. Pigment Red 122 20 parts by mass / Anionic surfactant 3 parts by mass (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC)
-Ion exchange water 78 mass parts The above was mixed and it disperse | distributed using the sand grinder mill. When the particle size distribution in the colorant particle dispersion 1 was measured using a particle size measuring device (LA-700, manufactured by Horiba, Ltd.), the average particle size of the contained colorant particles was 0.2 μm and 1 μm. No coarse particles exceeding were observed.

--- Preparation of release agent particle dispersion--
・ Mold release agent Fischer-Tropsch wax (melting point = 70 ° C.) 50 parts by mass ・ Anionic surfactant 7 parts by mass (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC)
・ Ion-exchanged water 200 parts by mass The above was heated to 95 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Turrax T50), and then dispersed with a pressure discharge homogenizer, and the average particle size was 0.5 μm. A release agent particle dispersion was prepared by dispersing the release agent.

--Preparation of charge control particle dispersion--
-5 parts by mass of a metal compound of di-alkyl-salicylic acid (charge control agent, Bontron E-84, manufactured by Orient Chemical Industries)
-3 parts by weight of anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC)
-Ion exchange water 78 mass parts The above was mixed and it disperse | distributed using the sand grinder mill. When the particle size distribution in the charge control particle dispersion 1 was measured using a particle size measuring device (LA-700, manufactured by Horiba, Ltd.), the average particle size of the charge control particles contained was 0.2 μm and 1 μm. No coarse particles exceeding were observed.

<Preparation of liquid mixture>
-Resin particle dispersion 1 280 parts by mass-Resin particle dispersion 2 100 parts by mass-Colorant dispersion 1 40 parts by mass-Release agent dispersion 70 parts by mass The above was equipped with a stirrer, condenser, and thermometer The mixture was put into a 1 liter separable flask and stirred. The mixture was adjusted to pH = 5.2 using 1N potassium hydroxide.

<Agglomerated particle formation>
To this mixed solution, 150 parts by mass of an 8% aqueous sodium chloride solution was added dropwise as a flocculant and heated to 55 ° C. with stirring. At this temperature, 3 parts by mass of resin particle dispersion 3 and 10 parts by mass of charge control agent particle dispersion were added. After maintaining at 55 ° C. for 2 hours, observation with an optical microscope confirmed that aggregated particles having an average particle diameter of about 3.3 μm were formed.

<Fusion process>
Then, after adding 3 mass parts of surfactant made from an anion (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) here, it heated to 95 degreeC, continuing stirring, and hold | maintained for 4.5 hours. And after cooling, the reaction product is filtered, washed thoroughly with ion-exchanged water, then fluidized-bed dried at 45 ° C, and the shape is adjusted by dispersing it in a gas phase of 200-300 ° C with a spray dryer. As a result, toner particles 4 were obtained. The physical properties of the obtained toner particles 4 are shown in Table 1.

<Manufacture of toner particles 5>
The toner particles 4 were classified by an air classifier. The physical properties of the obtained toner particles 5 are shown in Table 1.

  Next, production examples of fatty acid metal salts used in the present invention will be described.

<Production of fatty acid metal salt 1>
A receiving container with a stirrer was prepared, and the stirrer was rotated at 350 rpm. 500 mass parts of 0.5 mass% sodium stearate aqueous solution was thrown into this receiving container, and liquid temperature was adjusted to 85 degreeC. Next, 525 mass parts of 0.2 mass% zinc sulfate aqueous solution was dripped at this receptacle over 15 minutes. After the completion of charging the whole amount, the reaction was terminated by aging for 10 minutes at the temperature during the reaction.

Next, the fatty acid metal salt slurry thus obtained was washed by filtration. The obtained washed fatty acid metal salt cake was roughly crushed and then dried at 105 ° C. using a continuous instantaneous air dryer. Then, after pulverizing with a nano grinding mill [NJ-300] (manufactured by Sanrex) under conditions of an air volume of 6.0 m ³ / min and a processing speed of 80 kg / h, reslurry and fine particles using a wet centrifugal classifier After removal of the coarse particles, the fatty acid metal salt 1 was obtained by drying at 80 ° C. using a continuous instantaneous air flow dryer. The obtained fatty acid metal salt 1 had a median diameter (D50) of 0.45 μm and a span value B of 0.92. The physical properties of the fatty acid metal salt 1 are shown in Table 2.

<Production of fatty acid metal salt 2>
In the production of fatty acid metal salt 1, 0.5% by mass sodium stearate aqueous solution was added to 0.25% by mass sodium stearate aqueous solution, 0.2% by mass zinc sulfate aqueous solution to 0.15% by mass zinc sulfate aqueous solution, The pulverization conditions were changed to an air volume of 10.0 m ³ / min and the pulverization step was performed three times. Furthermore, after the resulting fatty acid metal salt is reslurried and fine particles and coarse particles are removed using a wet centrifugal classifier, the fatty acid metal salt 2 is obtained by drying at 80 ° C. using a continuous instantaneous air dryer. It was. The obtained fatty acid metal salt 2 had a median diameter (D50) of 0.18 μm and a span value B of 0.99. Table 2 shows the physical properties of the fatty acid metal salt 2.

<Production of fatty acid metal salt 3>
In the production of fatty acid metal salt 1, 0.5% by mass sodium stearate aqueous solution was changed to 1.0% by mass sodium stearate, and 0.2% by mass zinc sulfate aqueous solution was changed to 0.4% by mass zinc sulfate aqueous solution. . Further, the reaction was terminated by aging for 15 minutes. The pulverization condition was an air volume of 3.6 m ³ / min. Furthermore, after the resulting fatty acid metal salt is reslurried and fine particles and coarse particles are removed using a wet centrifugal classifier, the fatty acid metal salt 3 is obtained by drying at 80 ° C. using a continuous instantaneous air dryer. It was. The obtained fatty acid metal salt 3 had a median diameter (D50) of 0.90 μm and a span value B of 1.35. The physical properties of the fatty acid metal salt 3 are shown in Table 2.

<Production of fatty acid metal salt 4>
In the production of fatty acid metal salt 1, 0.5% by mass sodium stearate aqueous solution was added to 0.25% by mass sodium stearate aqueous solution, 0.2% by mass zinc sulfate aqueous solution to 0.15% by mass zinc sulfate aqueous solution, The pulverization conditions were changed to an air volume of 10.0 m ³ / min and the pulverization step was performed three times. Furthermore, when the obtained fatty acid metal salt was reslurried and fine particles and coarse particles were removed using a wet centrifugal classifier, the particle removal rate was weakened. Then, it dried at 80 degreeC using the continuous instantaneous airflow dryer, and obtained the fatty acid metal salt 4. The obtained fatty acid metal salt 4 had a median diameter (D50) of 0.18 μm and a span value B of 1.64. The physical properties of the fatty acid metal salt 4 are shown in Table 2.

<Production of fatty acid metal salt 5>
In the production of fatty acid metal salt 1, 0.5% by mass sodium stearate aqueous solution was changed to 1.0% by mass sodium stearate, and 0.2% by mass zinc sulfate aqueous solution was changed to 0.4% by mass zinc sulfate aqueous solution. . Further, the reaction was terminated by aging for 15 minutes. The pulverization condition was an air volume of 3.6 m ³ / min. Furthermore, when the obtained fatty acid metal salt was reslurried and fine particles and coarse particles were removed using a wet centrifugal classifier, the particle removal rate was weakened. Then, it dried at 80 degreeC using the continuous instantaneous airflow dryer, and obtained the fatty acid metal salt 5. The obtained fatty acid metal salt 5 had a median diameter (D50) of 0.90 μm and a span value B of 1.66. The physical properties of the fatty acid metal salt 5 are shown in Table 2.

<Production of fatty acid metal salt 6>
In the production of fatty acid metal salt 1, 0.5% by mass sodium stearate aqueous solution is changed to 0.25% by mass sodium stearate aqueous solution, and 0.2% by mass zinc sulfate aqueous solution is changed to 0.15% by mass zinc sulfate aqueous solution. Except for the above, the fatty acid metal salt 6 was obtained in the same manner as in the production of the fatty acid metal salt 1. The obtained fatty acid metal salt 6 had a median diameter (D50) of 0.32 μm and a span value B of 1.46. The physical properties of the fatty acid metal salt 6 are shown in Table 2.

<Production of fatty acid metal salt 7>
In the production of fatty acid metal salt 1, 0.5% by mass sodium stearate aqueous solution was changed to 1.0% by mass sodium stearate, and 0.2% by mass zinc sulfate aqueous solution was changed to 0.4% by mass zinc sulfate aqueous solution. . Further, the reaction was terminated by aging for 15 minutes. The pulverization condition was an air volume of 4.0 m ³ / min. Further, when the obtained fatty acid metal salt was reslurried and fine particles and coarse particles were removed using a wet centrifugal classifier, the removal rate of classification was weakened. Then, it dried at 80 degreeC using the continuous instantaneous airflow dryer, and obtained the fatty acid metal salt 7. The obtained fatty acid metal salt 7 had a median diameter (D50) of 0.72 μm and a span value B of 1.47. The physical properties of the fatty acid metal salt 7 are shown in Table 2.

<Production of fatty acid metal salt 8>
In the production of the fatty acid metal salt 1, the classification step after the pulverization step was not performed. Thereby, the fatty acid metal salt 8 was obtained. The obtained fatty acid metal salt 8 had a median diameter (D50) of 0.51 μm and a span value B of 1.81. The physical properties of the fatty acid metal salt 8 are shown in Table 2.

<Production of fatty acid metal salt 9>
In the production of fatty acid metal salt 1, 0.5% by mass sodium stearate aqueous solution was changed to 2.0% by mass sodium stearate, and 0.2% by mass zinc sulfate aqueous solution was changed to 1.0% by mass calcium chloride aqueous solution. . The reaction was terminated by aging for 5 minutes. Other steps were carried out in the same manner as in fatty acid metal salt 1 to obtain fatty acid metal salt 9. The obtained fatty acid metal salt 9 had a median diameter (D50) of 0.48 μm and a span value B of 1.01. Table 2 shows the physical properties of the fatty acid metal salt 9.

<Production of fatty acid metal salt 10>
In the production of fatty acid metal salt 1, the 0.2 mass% zinc sulfate aqueous solution was changed to a 0.3 mass% lithium chloride aqueous solution. Other than that was carried out similarly to the fatty-acid metal salt 1, and obtained the fatty-acid metal salt 10. FIG. The obtained fatty acid metal salt 10 had a median diameter (D50) of 0.48 μm and a span value B of 1.14. Table 2 shows the physical properties of the fatty acid metal salt 10.

<Production of fatty acid metal salt 11>
In the production of fatty acid metal salt 1, 0.5% by mass sodium stearate aqueous solution was added to 0.25% by mass sodium stearate aqueous solution, 0.2% by mass zinc sulfate aqueous solution to 0.15% by mass zinc sulfate aqueous solution, The pulverization conditions were changed to an air volume of 10.0 m ³ / min and the pulverization process was performed four times. Furthermore, after the resulting fatty acid metal salt is reslurried and fine particles and coarse particles are removed using a wet centrifugal classifier, the fatty acid metal salt 2 is obtained by drying at 80 ° C. using a continuous instantaneous air dryer. It was. The obtained fatty acid metal salt 11 had a median diameter (D50) of 0.12 μm and a span value B of 1.69. Table 2 shows the physical properties of the fatty acid metal salt 11.

<Fatty acid metal salt 12>
Commercially available zinc stearate (MZ2 manufactured by NOF Corporation) is used as fatty acid metal salt 12. The median diameter (D50) was 1.29 μm, and the span value B was 1.69. The physical properties of the fatty acid metal salt 12 are shown in Table 2.

<Toner Production Example 1>
To 100 parts by mass of toner particles (1), 0.10 parts of fatty acid metal salt (1) and 1.5 parts by mass of hydrophobic silica fine powder surface-treated with hexamethyldisilazane (number average primary particle size: 10 nm) Is mixed with a Henschel mixer (Mitsui Mining Co., Ltd.) for 150 seconds (mixing step 1). Thereafter, a pause process for 120 seconds is taken (pause process 1). Immediately after the pause process for 120 seconds, the mixing process is restarted, and the mixing process for 150 seconds is performed (mixing process 2). Thereafter, a pause process of 120 seconds is taken (pause process 2). Immediately after 120 seconds, mixing was resumed and mixing was continued for 150 seconds (mixing step 3). Thereafter, a pause process of 120 seconds is taken (pause process 3). After 120 seconds, mixing was resumed immediately and mixing was continued for 150 seconds (mixing step 4). By repeating the mixing step and the pause step as described above, the maximum temperature reached in the tank was about 34 ° C. The toner thus obtained is referred to as Toner 1. Table 3 shows the physical properties of Toner 1 thus obtained.

<Toner Production Examples 2 to 7, 9 to 15, 17, 18>
Under the same mixing conditions as in Toner Production Example 1, a toner was produced using a combination of toner particles, hydrophobic silica fine powder and fatty acid metal salt shown in Table 3. Table 3 shows the physical properties of the obtained toners.

<Toner Production Example 8>
In Toner Production Example 1, the mixing process time was changed to 200 seconds, the rest time was changed to 180 seconds, the number of mixing times was changed to 2, and the combination of toner particles, hydrophobic silica fine powder and fatty acid metal salt shown in Table 3 was used. Got. The maximum temperature reached in the tank was about 35 ° C. Table 3 shows the physical properties of Toner 8 thus obtained.

<Toner Production Example 16>
In Toner Production Example 1, the time of the first, second and third mixing steps was changed to 200 seconds, the time of the fourth mixing step was changed to 300 seconds, and the stop time between them was changed to 60 seconds. Toner 16 was obtained by combining particles, hydrophobic silica fine powder and fatty acid metal salt. The maximum temperature reached in the tank was about 39 ° C. Table 3 shows the physical properties of Toner 16 thus obtained.

<Toner Production Example 19>
In Toner Production Example 1, the mixing process time was changed to 150 seconds, the resting time was changed to 180 seconds, the number of mixing times was changed to 2, and the combination of toner particles, hydrophobic silica fine powder and fatty acid metal salt shown in Table 3 was used. Got. The maximum temperature reached in the bath was about 34 ° C. Table 3 shows the physical properties of Toner 19 thus obtained.

<Toner Production Example 20>
In Toner Production Example 1, the time of the first, second and third mixing steps was changed to 220 seconds, the time of the fourth mixing step was changed to 300 seconds, and the stop time between them was changed to 60 seconds. Toner 20 was obtained with a combination of particles, hydrophobic silica fine powder and fatty acid metal salt. The maximum temperature reached in the tank was about 40 ° C. Table 3 shows the physical properties of Toner 20 thus obtained.

  Next, the manufacturing method of the charging member of the present invention will be described.

[Production of resin particles 1]
A mixed solution of 400 parts by mass of ion-exchanged water, 8 parts by mass of polyvinyl alcohol (saponification degree 85%) and 0.04 parts by mass of sodium lauryl sulfate was prepared. On the other hand, a mixture of 0.1 parts by mass of ethylene glycol dimethacrylate, 0.5 parts by mass of benzoyl peroxide, 100 parts by mass of methyl methacrylate and 80 parts by mass of carbon black (average particle size 28 nm, pH = 6.0) was obtained as φ0. Using a Viscomil disperser filled with 5 mm zirconia beads, a mixed solution was prepared by dispersing for 60 hours at a peripheral speed of 10 m / s. Subsequently, the above-mentioned two kinds of solutions were put into a 2 liter four-necked flask equipped with a high-speed stirring device TK type homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and dispersed at a rotational speed of 13000 rpm. Thereafter, this dispersion was put into a polymerization vessel equipped with a stirrer and a thermometer, and the space was purged with nitrogen, and then stirred at 60 ° C. for 12 hours (rotation of the stirrer was 55 rpm) to complete suspension polymerization. After cooling, the suspension was filtered, washed, dried and classified to obtain resin particles 1. Table 4 shows the physical properties of the resin particles 1.

[Production of resin particles 2]
Acrylic particles “Art Pearl GR-400 Transparent” (trade name, manufactured by Negami Kogyo Co., Ltd.) are introduced into an electroless plating bath in which nickel is dissolved and nickel oxide is dispersed. A composite film of the product was formed to obtain resin particles 2. Table 4 shows the physical properties of the resin particles 2.

[Resin particles 3]
Acrylic particles “Art Pearl GR-400 Transparent” (trade name, manufactured by Negami Kogyo Co., Ltd.) were used as resin particles 3. Table 4 shows the physical properties of the resin particles 3.

[Resin particles 4]
Acrylic particles “Art Pearl J-4PY” (trade name, manufactured by Negami Kogyo Co., Ltd.) were classified by wind classification to obtain resin particles 4. Table 4 shows the physical properties of the resin particles 4.

[Resin particles 5]
Acrylic particles “Art Pearl SE-050T” (trade name, manufactured by Negami Kogyo Co., Ltd.) were classified by wind classification to obtain resin particles 5. Table 4 shows the physical properties of the resin particles 5.

[Resin particles 6]
Acrylic particles “Art Pearl SE-050T” (trade name, manufactured by Negami Kogyo Co., Ltd.) were used as resin particles 6. Table 4 shows the physical properties of the resin particles 6.

[Production of conductive composite fine particles]
140 g of methylhydrogenpolysiloxane was added to 7.0 kg of silica particles (average particle size of 15 nm, volume resistivity of 1.8 × 10 ¹² Ω · cm) while operating the edge runner, and 588 N / cm (60 kg / cm). The mixture was stirred for 30 minutes with a linear load of. The stirring speed at this time was 22 rpm. Next, 7.0 kg of carbon black particles (average particle size 28 nm, pH = 6.5) are added over 10 minutes while the edge runner is running, and further 60% with a linear load of 588 N / cm (60 kg / cm). Mixing and stirring were performed for a minute. After carbon black was attached to the silica particles coated with methylhydrogenpolysiloxane, drying was performed at 80 ° C. for 60 minutes using a dryer to obtain conductive composite fine particles. In addition, the carbon black adherence also had a stirring speed of 22 rpm. The obtained conductive composite fine particles had an average particle size of 15 nm and a volume resistivity of 2.3 × 10 ² Ω · cm.

[Production of surface-treated titanium oxide particles]
A slurry was prepared from 1000 g of acicular rutile-type titanium oxide particles (average particle size 15 nm, length: width = 3: 1), 110 g of a surface treatment agent isobutyltrimethoxysilane and 3000 g of solvent toluene. This slurry was mixed for 30 minutes with a stirrer and then supplied to Viscomill in which 80% of the effective internal volume was filled with glass beads having a diameter of 0.8 mm, and wet crushing was performed at a temperature of 35 ± 5 ° C. Toluene was removed from the slurry obtained by the wet pulverization treatment by distillation under reduced pressure (bath temperature: 110 ° C., product temperature: 30 ° C. to 60 ° C., degree of vacuum: about 13.3 kPa (100 Torr)) using a kneader, The surface treatment agent was baked at 120 ° C. for 2 hours. The particles after the baking treatment were cooled to room temperature and then pulverized using a pin mill to obtain surface-treated titanium oxide.

[Manufacture of raw material roller having conductive elastic layer]
A stainless steel core having a diameter of 6 mm and a length of 252.5 mm was used as a conductive support. A thermosetting adhesive (Metallock U-20 manufactured by Toyo Chemical Laboratory Co., Ltd.) was applied to this and dried.

  Epichlorohydrin rubber (EO-EP-AGC terpolymer, EO / EP / AGE = 73 mol% / 23 mol% / 4 mol%) 100 parts by mass The following components were added and the closed mixer adjusted to 50 ° C. Was mixed for 10 minutes to prepare a raw material compound.

Calcium carbonate 60 parts by weight Aliphatic polyester plasticizer 8 parts by weight Zinc stearate 1 part by weight 2-mercaptobenzimidazole (MB) (anti-aging agent) 0.5 part by weight Zinc oxide 2 parts by weight Quaternary ammonium salt 1.5 5 parts by mass of carbon black (average particle size 100 nm, volume resistivity 0.1 Ω · cm)

  To this, 1 part by mass of sulfur as a vulcanizing agent, 1 part by mass of dibenzothiazyl sulfide (DM) and 0.5 part by mass of tetramethylthiuram monosulfide (TS) as vulcanization accelerators were added and cooled to 20 ° C. The compound for conductive elastic layers was obtained by kneading for 10 minutes with a two-roll mill.

  Along with the conductive support, the conductive elastic layer compound is extruded with a crosshead extruder and molded into a roller shape having an outer diameter of about 9 mm. Time, vulcanization and curing of the adhesive were performed. Cut both ends of the rubber so that the rubber length is 228 mm, and then the surface is polished to form a roller shape with an outer diameter of 8.5 mm to form a conductive elastic layer on the conductive support. The raw material roller was obtained. The crown amount of this raw material roller (the difference in the outer diameter at a position 90 mm away from the central portion and the central portion) was 120 μm.

<Manufacture of charging member 1>
[Preparation of coating solution for surface layer]
Methyl isobutyl ketone was added to caprolactone-modified acrylic polyol solution “Placcel DC2016” (trade name, manufactured by Daicel Chemical Industries, Ltd.) to adjust the solid content to 17% by mass.

  The following components were added to 588.2 parts by mass of this solution (100 parts by mass of acrylic polyol solid content) to prepare a mixed solution.

Composite conductive fine particles 50 parts by mass Surface-treated titanium oxide particles 30 parts by mass Modified dimethyl silicone oil ^{* 1} 0.08 parts by mass Blocked isocyanate mixture ^{* 2} 80.14 parts by mass At this time, the blocked isocyanate mixture has an NCO content of “NCO”. /OH=1.0 ”.
* 1) Modified dimethyl silicone oil “SH28PA” (trade name, manufactured by Toray Dow Corning Silicone Co., Ltd.)
* 2) A 7: 3 mixture of each butanone oxime block of hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI). For HDI and IPDI, HDI “Duranate TPA-B80E” (trade name: manufactured by Asahi Kasei Kogyo Co., Ltd.) and IPDI “Vestanat B1370” (trade name, manufactured by Degussa Huls) were used.

  210 g of the above mixed solution was put in a glass bottle having an internal volume of 450 mL together with 200 g of glass beads having an average particle diameter of 0.8 mm as a medium, and dispersed for 72 hours using a paint shaker disperser. After the dispersion, 2.72 g (corresponding to 10 parts by weight with respect to 100 parts by weight of the acrylic polyol solid content) of the conductive resin particles 1 prepared in Production Example 1 were added, and then dispersed for another 5 minutes. The beads were removed to obtain a coating solution for the surface layer.

[Manufacture of charging members]
Using the raw material roller obtained above, the surface layer coating solution is dipped once, air-dried at room temperature for 30 minutes or more, and then dried at 80 ° C. for 1 hour and further at 160 ° C. for 1 hour in a hot air circulating dryer. Thus, a surface layer was formed on the conductive elastic layer to obtain a charging member having the conductive elastic layer and the surface layer on the conductive support. The dipping coating was performed by changing the speed linearly with respect to time, with a dipping time of 9 seconds, a dipping coating lifting speed, an initial speed of 20 mm / s, and a final speed of 2 mm / s. Table 4 shows the physical properties of the obtained charging member.

<Manufacture of charging members 2 to 11>
A charging member was obtained by the same manufacturing method as that of the charging member 1 with the resin particles and the number of added parts shown in Table 4. Table 4 shows the physical properties of the obtained charging members.

<Image evaluation>
The image evaluation was performed by partially modifying a commercially available color laser printer HP Color LaserJet 4700dn (manufactured by HP). In the modification, the process speed was changed to 240 mm / sec so that the fixing temperature could be set to an arbitrary temperature. Furthermore, it has been improved so that it can operate even when only one color process cartridge is installed.

After removing the toner contained in a commercially available black cartridge and cleaning the inside by air blow, the test toner (320 g) and a toner carrier are mounted on the cartridge, and the cartridge is placed in a low temperature and low humidity environment (15 ° C.). 10% RH) and high temperature and high humidity environment (30 ° C., 80% RH) were evaluated for developability and durability. The image evaluation items are as follows, and the image evaluation under the low-temperature and low-humidity and high-temperature and high-humidity environment was performed after printing 20,000 sheets and 40,000 sheets of images with a printing rate of 1% at the initial stage. LETTER size XEROX 4024 paper (manufactured by XEROX, 75 g / m ² ) was used as the transfer material.

[Development stripes]
After the initial printout test of 10,000 sheets, 20,000 sheets, and 30,000 sheets, a halftone image (toner loading amount: 0.3 mg / cm ² ) on transfer paper (75 g / m ² , A4 size paper) Images were printed out and evaluated by the number of development lines.
A: Not generated B: 1 or more, 3 or less C: 4 or more, 6 or less D: 7 or more, or a line having a width of 0.5 mm or more

[Filming]
The filming of the toner carrier was evaluated by visual observation and image of the surface of the toner carrier.
In the initial halftone image after printing 20,000 sheets and 40,000 sheets (toner loading: 0.3 mg / cm ² ), there is no density unevenness between the 1% printed image portion and the non-printed image portion. It was evaluated visually. Thereafter, the toner on the surface of the toner carrier was blown with air, and the surface of the toner carrier was observed.
A: There is no occurrence of uneven density on the image and the surface of the toner carrier is good. B: No unevenness of density is generated on the image, but some filming is confirmed on the surface of the toner carrier.
C: Mild shading unevenness on the image D: Slight shading unevenness on the image

<Discharge failure image>
Half-tone images (images that draw a horizontal line with a width of 1 dot and a spacing of 2 dots in the direction perpendicular to the rotation direction of the photoconductor) are used and evaluated according to the following criteria after printing 20,000 sheets, 30,000 sheets, and 40,000 sheets. It was.
A: Very good.
B: Good.
C: The halftone image has slight streak-like and point-like image defects.
D: A streak-like or spot-like image defect is conspicuous.

<Examples 1 to 22>
Evaluation was performed using the toner and the charging member shown in Table 5. The results are shown in Table 5. They gave good results.

<Comparative Examples 1 to 8>
Evaluation was performed using the toner and the charging member shown in Table 6. The results are shown in Table 6.

1 is a cross-sectional view of an image forming apparatus.

Explanation of symbols

21 Photosensitive drum 22 Charging member 23 Laser beam 24 Developing device 25 Developing roller 26 Developer supplying roller 27 Developing blade 28 Developer 29 Transfer roller 30 Cleaning blade 31 Waste developer container 32 Fixing device 33 Paper 34 Developing container

Claims (10)

A charging step for charging the electrostatic latent image carrier with a charging member, an exposure step for exposing the charged electrostatic latent image carrier to form an electrostatic latent image, and development for developing the electrostatic latent image with toner In an image forming method comprising a step of transferring a toner image to a transfer material with or without an intermediate transfer member,
The surface layer of the charging member is a layer in which resin particles are dispersed in a binder resin, and convex portions derived from the resin particles are formed on the surface of the charging member. The roughness Rzjis is 2 μm or more and 30 μm or less, and the average interval Sm of the irregularities on the surface of the charging member is 7 μm or more and 150 μm or less,
The toner has toner particles and a fatty acid metal salt, and the median diameter (D50) of the fatty acid metal salt on a volume basis is 0.15 μm or more and 1.00 μm or less, and the fatty acid metal salt is liberated in the toner. An image forming method, wherein the rate is 1.0% or more and 30.0% or less. The image forming method according to claim 1, wherein a span value B defined by the following formula (1) of the fatty acid metal salt is 1.75 or less.
Span value B = (D95s−D5s) / D50s (1) Formula D5s: 5% integrated diameter based on volume of fatty acid metal salt D50s: median diameter based on volume of fatty acid metal salt (D50)
D95s: 95% integrated diameter of fatty acid metal salt based on volume 3. The image forming method according to claim 2, wherein a span value A defined by the following formula (2) of the toner particles and a span value B of the fatty acid metal salt satisfy the following formula (3).
Span value A = (D90t−D10t) / D50t (2) Expression D10t: 10% integrated diameter based on the number of toner particles D50t: Median diameter based on the number of toner particles (D50)
D90t: 90% integrated diameter based on the number of toner particles 0.25 ≦ (A / B) ≦ 0.75 (3)   4. The image forming method according to claim 1, wherein a liberation rate of the fatty acid metal salt in the toner is 2.0% or more and 25.0% or less.   The image forming method according to claim 1, wherein the fatty acid metal salt is fatty acid zinc or fatty acid calcium. 4. The image according to claim 2 , wherein a median diameter (D50) of the fatty acid metal salt on a volume basis is 0.30 μm or more and 0.75 μm or less, and the span value B is 1.50 or less. 5. Forming method.   The image forming method according to claim 1, wherein the resin particles have a volume average particle diameter (Dv) of 1 μm to 40 μm.   The image forming method according to claim 1, wherein an average interval Sm between the irregularities on the surface of the charging member is 15 μm or more and 120 μm or less.   The image forming method according to claim 1, wherein the resin particles are conductive.   The image forming method according to claim 1, wherein the resin particles contain carbon black.

Images