JP2015175870A - Image forming apparatus, image forming method, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus configured to form a high-resolution high-quality image free from scumming or character blur, even in the beginning and after a long time printing, in response to a request for high-speed image formation.SOLUTION: An image forming apparatus includes developing means that develops an electrostatic latent image formed on an electrostatic latent image carrier with developer stored in a developer storage section having the developer including carrier and toner, to form a toner image. The carrier includes at least one of initial carrier and supply carrier. There is a specific relationship between the amount of charge on the initial carrier and that on the supply carrier when the initial carrier or the supply carrier is agitated with te toner under a specific condition.

Description

  The present invention relates to an image forming apparatus, an image forming method, and a process cartridge using electrophotography, electrostatic recording, and the like.

In a two-component developing device used in an image forming apparatus, a two-component developer containing toner and a carrier contained in the developer containing portion is stirred and frictionally charged, and then a developer carrying carrier Is supplied to the electrostatic latent image carrier and the latent image on the electrostatic latent image carrier is developed. At this time, the toner is consumed and reduced, but the carrier is not consumed. It remains in the (developer container). For this reason, the carrier has a higher agitation frequency in the developer accommodating portion than the toner, and easily deteriorates accordingly. Such deterioration of the carrier makes the charge amount of the toner unstable, for example, and causes a decrease in image quality.
Therefore, in order to suppress the deterioration of the carrier, not only the toner but also the carrier is appropriately replenished to the developer accommodating portion, and the two-component developer that gradually becomes excessive by the carrier replenishment is recovered. As a result, a method of replacing the deteriorated carrier in the developer accommodating portion with a new carrier to be replenished, that is, so-called “trickle development” has been introduced.

However, this trickle development technique has the following problems.
Along with the recent demand for higher speed image formation, the carrier is subjected to strong agitation in the developer container. On the other hand, strong agitation is not applied to the replenishment developer in the replenishment cartridge that is replenished to the developer container. The replenishment developer generally has a low carrier presence rate for the purpose of suppressing torque in the transport path during replenishment. If the developer for replenishment is subjected to strong agitation before being replenished to the developer container, the toner will be greatly damaged, causing the external additive to be buried, and the fluidity of the toner will be deteriorated. Inconvenience occurs in the conveyance of the toner, and as a result, problems such as toner ground contamination due to poor charging rise. For this reason, the replenishment developer in the replenishment cartridge is not sufficiently agitated until it is replenished to the developer container.

  As described above, the replenishment developer has a low carrier, has a high toner concentration, and is not sufficiently stirred, so that the toner is replenished to the developer accommodating portion with a low charge amount. On the other hand, the developer in the developer accommodating portion is sufficiently agitated, and the toner in the developer accommodating portion has a desired charge amount. For this reason, when the replenishment developer is replenished, toners having different charge amounts are mixed in the developer accommodating portion. If toners with different charge amounts are mixed, the weakly charged toner will be excessively deposited on the electrostatic latent image carrier and developed, so that it will be developed in areas other than the desired location, causing toner smearing and stable. You can not get a good picture quality.

  By changing the charging characteristics of the carrier, it is possible to make the toner in the replenishment cartridge before it is replenished to the developer accommodating portion easily develop triboelectric charge even with weak agitation. In a low state, the toner may be excessively charged, and in such a case, the developing performance is deteriorated, causing a problem such as blurred characters.

With respect to the above problems, research has been conducted on the charge amount of the developer in the developer container and the charge amount of the developer in the replenishment cartridge, and various reports have been made.
For example, in order to obtain stable image quality over a long period of time, a developing method that specifies that the charge amount of the carrier in the replenishment cartridge is larger than the carrier in the developer container is disclosed (for example, Patent Documents 1, 2, and 3). reference).

  However, from the viewpoint of stably realizing higher definition and higher image quality over a long period of time in response to the recent demand for higher speed image forming apparatuses, these disclosed methods are still not satisfactory. There was room for improvement.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention provides an image forming apparatus capable of forming a high-definition and high-quality image with no background smudges and blurring of characters at the time of initial printing and long-term printing in response to a request for high-speed image formation. For the purpose of provision.

Means for solving the problems are as follows. That is, the image forming apparatus of the present invention includes an electrostatic latent image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image carrier. The electrostatic latent image formed on the toner is developed using the developer accommodated in a developer accommodating portion having a developer containing a carrier and a toner to form a toner image, and the electrostatic latent image An image forming apparatus having transfer means for transferring the toner image formed on the image carrier to a recording medium,
The carrier has at least one of an initial carrier and a replenishment carrier;
The developing means includes a replenishing member that replenishes the developer accommodating portion with the replenishment developer from a replenishment cartridge having a replenishment developer including at least the replenishment carrier;
When the replenishment carrier and the toner are stirred using a tumbler mixer at 67 rpm for 1 minute, the charge amount of the replenishment carrier is CA1-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a tumbler mixer is CA1-2 (μC / g), CA1-1 is 8 (μC / g) from CA1-2. g) to 20 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 6 (μC of the CA2-2. / G).

  According to the present invention, the above-mentioned problems can be solved and the above-mentioned object can be achieved. In response to the demand for high-speed image formation, background stains and text blurring can be achieved both at the initial printing time and at the long-time printing time. Therefore, it is possible to provide an image forming apparatus capable of forming a high-definition and high-quality image.

FIG. 1 is a diagram illustrating an example of an image forming apparatus according to the present invention. FIG. 2 is a diagram illustrating an example of the process cartridge of the present invention. FIG. 3 is a view for explaining a cell for measuring the volume resistivity of the electrostatic latent image developing carrier in the present invention.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention includes an electrostatic latent image carrier, an electrostatic latent image forming unit, a developing unit, and a transfer unit, and further includes other units such as a fixing unit and a cleaning unit as necessary. Means, static elimination means, recycling means, control means, and the like.
The image forming method of the present invention includes an electrostatic latent image forming step, a developing step, and a transfer step, and further, if necessary, other steps such as a fixing step, a cleaning step, a static elimination step, a recycling step, Including control processes.
The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming means, and the developing step is the developing The transfer step can be performed by the transfer unit, and the other steps can be performed by the other units.

<Electrostatic latent image carrier>
The electrostatic latent image carrier is not particularly limited as long as an electrostatic latent image is formed by the electrostatic latent image forming unit, and can be appropriately selected according to the purpose. And a photosensitive layer, and a surface protective layer, and further include other layers as necessary.
The layer structure of the electrostatic latent image carrier is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a support and a photosensitive layer (charge generation layer) having at least a laminated structure on the support , A charge transport layer), and a surface protective layer in this order, and may have an undercoat layer as necessary, and includes a configuration in which the surface protective layer comes to the outermost surface. In addition, a mode in which a photosensitive layer having a single layer structure mainly composed of a charge generating substance and a charge transporting substance on a support and a surface protective layer on the photosensitive layer may be used.

<Electrostatic latent image forming means and electrostatic latent image forming step>
The electrostatic latent image forming means is not particularly limited as long as it is a means for forming an electrostatic latent image on the electrostatic latent image carrier, and can be appropriately selected according to the purpose. And means for forming an electrostatic latent image by combining the means and the exposure means.
The electrostatic latent image forming step is not particularly limited as long as it is a step of forming an electrostatic latent image on the electrostatic latent image carrier, and can be appropriately selected according to the purpose. A step of forming an electrostatic latent image by combining the step and the exposure step may be mentioned.
The charging means is not particularly limited as long as it is a means for charging the surface of the electrostatic latent image carrier, and can be appropriately selected according to the purpose. There is a means for applying a voltage to the surface of the latent image carrier.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charger provided with a conductive or semiconductive roller, brush, film, rubber blade, or the like. And non-contact chargers utilizing corona discharge such as corotron and scorotron.
The exposure unit is not particularly limited as long as it is a unit that exposes the surface of the electrostatic latent image carrier charged by the charging unit like an image to be formed, and is appropriately selected according to the purpose. Examples of the exposure apparatus include a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system.

<Developing means and development process>
The developing means develops the electrostatic latent image formed on the electrostatic latent image carrier using the developer accommodated in a developer accommodating portion having a developer containing a carrier and toner, It is a means for forming a toner image.
In the developing step, the electrostatic latent image formed on the electrostatic latent image carrier is developed using a developer containing a carrier and toner, which is contained in a developer containing unit, to form a toner image. It is a process to do.
The carrier includes at least one of an initial carrier and a replenishment carrier.
The developing means includes a replenishment member that replenishes the developer containing portion with the replenishment developer from a replenishment cartridge having a replenishment developer including at least the replenishment carrier.
The developing step includes a replenishment process for replenishing the developer accommodating portion with a replenishment developer including at least a replenishment carrier from a replenishment cartridge.
The developing means is not particularly limited as long as it is a means for developing the electrostatic latent image formed on the electrostatic latent image carrier using a developer containing toner to form a toner image. The toner image can be selected using, for example, a developing device that has the function of containing the developer and imparting the developer to the electrostatic latent image in a contact or non-contact manner. Preferably formed.

The developing device of the present invention has a developer accommodating portion that accommodates a developer containing a carrier and toner.
The developing device may be of a dry development type or a wet development type, and may be a single color development device or a multicolor development device.

In addition, the developing device preferably includes a stirrer for stirring and charging the toner and the carrier in the developer container, and a rotatable magnet roller.
In the developer accommodating portion, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrostatically attracted by the static force. It moves to the surface of the electrostatic latent image carrier. As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the electrostatic latent image carrier.

  Further, the developing device of the present invention has a replenishment cartridge that accommodates the replenishment developer, and a replenishment member that replenishes the developer accommodating portion with the replenishment developer in the replenishment cartridge. Have.

In the present invention, the charge amount of the carrier is measured by a method described later, and the charge amount of the carrier when stirred for 1 minute is represented as CA1, and the charge amount of the carrier when stirred for 10 minutes is represented as CA2. CA1 of the replenishment carrier is particularly represented as CA1-1, and CA1 of the initial carrier is particularly represented as CA1-2. Further, CA2 of the replenishment carrier is particularly represented as CA2-1, and CA2 of the initial carrier is particularly represented as CA2-2.
The developing device of the present invention preferably has a recovery member for recovering excess developer in the developer accommodating portion. By appropriately replenishing not only the toner but also the carrier to the developer accommodating portion, the toner that is reduced due to consumption can be replenished, and at the same time, the deteriorated carrier can be replaced with a new carrier. This is because an excessive developer is present, and the unnecessary developer is recovered.

  When a replenishment developer composed of a replenishment carrier and toner, each having a desired CA1 value or CA2 value, is used, and image formation is performed while discharging excess developer in the developing device, it is much more difficult than before. A stable quality image can be formed over a long period of time. That is, the deteriorated carrier in the developing device and the non-deteriorated carrier in the replenishing developer are replaced, and the charge amount can be kept stable over a long period of time, and a stable image can be obtained. This is particularly effective when printing a high image area. When printing on a large image area, carrier charge deterioration due to toner spent on the carrier is the main carrier deterioration, but using a method that incorporates recovery means, the amount of carrier replenishment increases when the image area is high, so degradation The frequency with which the selected carriers are replaced increases. Thereby, a stable image can be formed over an extremely long period of time. However, with the recent demand for higher speed, only the recovery means is insufficient, and therefore, the present invention defines the CA1-1, the CA1-2, the CA2-1, and the CA2-2, By using a replenishment developer having a specific replenishment carrier and an initial developer having a specific replenishment carrier, the combined effects of the present invention can be exhibited.

<< Supply Member >>
The replenishing member is not particularly limited as long as it replenishes the developer accommodating portion with the replenishing developer in the replenishing cartridge, and is selected according to the purpose.

<< Developer >>
The developer is a two-component developer containing a carrier and a toner.
In the present invention, the developer includes both the replenishment developer and the initial developer accommodated in the developer accommodating portion before replenishment.
In the present invention, the carrier means a developing carrier, and is included in the replenishment carrier (hereinafter also referred to as “second carrier”) included in the replenishment developer and the initial developer. Any of the initial carriers (hereinafter also referred to as “first carrier”) is included.
In the present invention, the replenishment developer and the initial developer have different toner and carrier mixing ratios and carrier types.

The replenishment carrier and the initial carrier have the following properties.
When the replenishment carrier and the toner are stirred at 67 rpm for 1 minute using a tumbler mixer, the charge amount of the replenishment carrier is CA1-1 (μC / g), and the initial carrier and the toner are When the charge amount of the initial carrier when CA1 is stirred at 67 rpm for 1 minute using a tumbler mixer is CA1-2 (μC / g), the CA1-1 is 8 (μC / g) from the CA1-2. It is preferably ˜20 (μC / g) high, more preferably 10 (μC / g) to 15 (μC / g) high.
When the replenishment carrier and the toner are stirred for 10 minutes at 67 rpm using a tumbler mixer, the charge amount of the replenishment carrier is CA2-1 (μC / g), and the initial carrier and the toner are When the charge amount of the initial carrier when the mixture is stirred at 67 rpm for 10 minutes using a turbuler mixer is CA2-2 (μC / g), the CA2-1 is ± 6 (μC / g of the CA2-2. ) Is preferable, and within ± 4 (μC / g) is more preferable.

The present inventors consider the charge amount of the developer with respect to weak stirring stress and the charge amount of the developer with respect to strong stirring stress as the most important parameters, and a carrier that exhibits a desired charge amount in two states of weak stirring and strong stirring. It has been found that the problem of the present invention can be solved by properly using the carrier for the replenishment carrier and the initial carrier and using the carrier for the image forming apparatus.
In the present invention, the difference in charge amount caused by the degree of stirring is grasped by the difference in stirring time. Use a tumbler mixer that allows stable stirring and that can be quickly mixed even with weak stirring so that the amount of charge can be accurately grasped by stirring time.
The present inventors use a tumbler mixer to observe the change in the charge amount with the stirring time. When stirring at 67 rpm, the state where the stirring time is 1 minute and 10 minutes is replenished in the actual machine. It was found that the state of the developer subjected to the agitation stress can be expressed in the cartridge for use or in the developer container.

The CA1-1, the CA1-2, the CA2-1, and the CA2-2 have the above relationship, that is, the replenishment carrier has a high CA1 value and a moderately low CA2 value. When both the CA1 value and the CA2 value are appropriately selected as the initial carrier, and both are combined with the toner and used as a replenishment developer and an initial developer, good results are obtained. can get.
The replenishment carrier is relatively gently agitated in the replenishment cartridge or in the transport path to the developer container. Even with this agitation, the toner is developed to a certain extent by giving the toner a certain charging ability. It is considered that the charging deviation from the toner in the developer accommodating portion can be suppressed after being introduced into the developer accommodating portion, and problems caused thereby can be effectively prevented. Further, once the developer container is replenished, it is desirable that the charging ability given to the toner is suppressed even when subjected to strong agitation.
Since the initial carrier is vigorously stirred in the developer accommodating portion from the start of printing, it is desirable that the charging ability applied to the toner is suppressed.

  There are various methods for adjusting the CA1 value and the CA2 value. For example, the type and amount of charge adjusting agent for the carrier are appropriately selected, the type of the carrier resin is appropriately selected, and the resistance of the carrier is selected. The method of adjusting etc. is mentioned.

In the present invention, since the amount of charge when the stirring time is short is regarded as important, since the blow is strong at the time of charge measurement, accurate measurement cannot be performed if stirring occurs. Therefore, it is preferable to use a blow-off device disclosed in Japanese Patent Application Laid-Open No. 08-313487 for measuring the charge amount.
Specifically, the values of CA1 and CA2 can be obtained as follows.

[CA1, CA2 values]
First, 9.0 g of carrier and 0.678 g of toner are put into a stainless steel container having a diameter of 2.5 cm and a height of 3.0 cm.
This container is set in a tumbler mixer (manufactured by Glen Mills) together with a suitable spacer and stirred at 67 rpm.
Here, the toner used in the actual machine is used as the toner. In the present invention, measurement is performed using a commercially available toner used in the examples.
For the sample stirred for 1 minute, the charge amount of the carrier is measured using a blow-off device disclosed in Japanese Patent Application Laid-Open No. 08-313487, and the CA1 (μC / g) value is obtained.
In the present invention, when the carrier whose CA1 value is measured is used as a replenishing carrier, the CA1 value is set as a CA1-1 (μC / g) value, and when the carrier is used as an initial carrier, the CA1 value is set as CA1-2. (ΜC / g) value.
Similarly, the charge amount of the carrier is measured for a sample stirred for 10 minutes, and the CA2 (μC / g) value is obtained. Similar to CA1, in the present invention, when the carrier whose CA2 value is measured is used as a replenishing carrier, the CA2 value is used as the CA2-1 (μC / g) value, and when the carrier is used as the initial carrier, the CA2 value is obtained. Is the CA2-2 (μC / g) value.

  As measurement conditions of the present invention, [Example / Operation Example 3] in Japanese Patent Application Laid-Open No. 08-313487, except that the mesh is changed from # 635 to # 795 (mesh size 16 μm, wire diameter 16 μm, space factor 25%). According to The height setting value is set in three stages, h1 = 55 h2 = 0 h3 = 0, the suction pressure is set to 100 for P1, P2 and P3, and the measurement is performed with 0.30 g of developer. The measurement environment is a measurement value at 23 ° C. and 50% RH.

The blending ratio of the toner and the replenishment carrier in the replenishment developer accommodated in the replenishment cartridge is preferably 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier. When the amount of toner is less than 2 parts by mass, the amount of replenishment carrier is excessive, the carrier supply is excessive, and the carrier concentration in the developing device becomes too high. And the toner is dissolved by heat, and toner spent tends to occur. Further, when the developer charge amount increases, the developing ability decreases and the image density decreases. On the other hand, when the amount exceeds 50 parts by mass, the carrier ratio in the replenishment developer decreases, so that the replacement of carriers in the image forming apparatus decreases, and the effect on carrier degradation that was originally intended cannot be expected.
The blending ratio of the toner and the initial carrier in the initial developer accommodated in the developer accommodating unit is preferably 3 parts by mass to 15 parts by mass of the toner with respect to 100 parts by mass of the carrier.

  In the present invention, the carrier described below is preferably used for adjusting the CA1 value and the CA2 value to be desired values and adjusting the relationship defined in the present invention.

<<< Career >>>>
In the present invention, the carrier includes both a replenishment carrier and an initial carrier.
The carrier includes magnetic core particles and a resin layer that covers the surface of the core particles, and further includes other components as necessary.
In the present invention, as described above, the CA1 value is selected by a method such as appropriately selecting the type and amount of charge adjusting agent contained in the carrier, appropriately selecting the type of carrier resin, and adjusting the carrier resistance. , And the CA2 value can be adjusted to a desired value.

The carrier preferably has a volume average particle size of 23 μm to 57 μm, more preferably 32 μm to 40 μm.
When the volume average particle diameter of the carrier is less than 23 μm, carrier adhesion may occur. When the volume average particle diameter exceeds 57 μm, the reproducibility of image details may be reduced and a fine image may not be formed.
The volume average particle diameter can be measured using, for example, a Microtrac particle size distribution model HRA9320-X100 (manufactured by Nikkiso Co., Ltd.).

The volume resistivity of the carrier is preferably 8 (Log Ω · cm) to 14 (Log Ω · cm). If the volume resistivity is less than 8 (Log Ω · cm), carrier adhesion may occur in the non-image area, and if it exceeds 14 (Log Ω · cm), the edge effect may be at an unacceptable level. is there.
Under actual usage conditions, factors other than volume specific resistance such as toner concentration, magnetization characteristics of core material particles, and usage environment are also involved. Considering this, the volume resistivity is more preferably 9.5 (Log Ω · cm) to 12.1 (Log Ω · cm).

  The volume resistivity can be measured using the cell shown in FIG. Specifically, first, a carrier (3) is placed in a cell composed of a fluororesin container (2) in which an electrode (1a) and an electrode (1b) having a surface area of 2.5 cm × 4 cm are accommodated at a distance of 0.16 cm. ) And is tapped 10 times with a drop height of 1 cm and a tapping speed of 30 times / minute. Next, a DC voltage of 1,000 V is applied between the electrodes (1a) and (1b), and the resistance value r [Ω] after 30 seconds is used with a high resistance meter 4329A (manufactured by Yokogawa Hewlett-Packard Company). The volume resistivity (Ω · cm) can be calculated from the following formula 1.

    r × (2.5 × 4) /0.16 Formula 1

-Core particles-
The core material particle having magnetism is not particularly limited as long as it is a magnetic substance, and can be appropriately selected according to the purpose. Examples thereof include ferromagnetic metals such as iron and cobalt, magnetite, hematite, and ferrite. Examples thereof include resin particles in which magnetic materials such as iron oxide, various alloys, and compounds are dispersed in a resin. Among these, Mn type ferrite, Mn—Mg type ferrite, Mn—Mg—Sr ferrite and the like are preferable from the viewpoint of environmental considerations.
As the bulk density of the core material ^{particles, 1.8g / cm 3 ~2.2g / cm} 3 are preferred. When the bulk density is less than 1.8 g / cm ³ , so-called carrier adhesion that causes the carrier to adhere to the electrostatic latent image carrier is likely to occur. When the bulk density exceeds 2.2 g / cm ³ , stirring in the developing machine occurs. The stress increases, that is, the deterioration of the carrier coat layer progresses quickly, and the resistance change of the carrier increases.
In addition, since the volume average particle diameter of the carrier is more preferably 32 μm to 40 μm as described above, also in the core material particle, the particle having a size obtained by removing the thickness of the resin layer from the volume average particle diameter of the carrier particle. The diameter is preferable.

-Resin layer-
The resin layer covers the surface of the core material and includes a resin and conductive fine particles.
The resin layer of the carrier of the present invention is mainly composed of the resin and the conductive fine particles, each having a function.
The conductive fine particles have three functions, namely, a resistance adjusting function, a function of scraping the spent product of the recessed parts by providing minute irregularities on the carrier surface, and an improvement of the resin layer strength.
The resin has a function as a binder and a function of suppressing toner spent on the toner surface adhering to the carrier surface.

  In the present invention, the resin layer preferably has no film defects, and the average thickness is preferably 0.05 μm to 0.90 μm. If the average thickness is less than 0.05 μm, the resin layer tends to be broken by use, and the film may be scraped. If the average thickness exceeds 0.90 μm, the resin layer is not a magnetic substance, so Adhesion may occur and the resistance adjusting effect described later is not sufficiently exhibited.

  In order to obtain the function of conductive fine particles, the resin layer of the carrier of the present invention preferably contains a certain amount or more of conductive fine particles. Specifically, the resin layer preferably contains 1% by mass to 3% by mass. By containing 1% by mass to 3% by mass, the resin layer can be provided with appropriate hardness.

--Conductive fine particles--
The conductive fine particles have at least two layers of a base and a conductive layer covering the surface of the base and containing tin.
As will be described later, the conductive fine particles may be subjected to a surface treatment, and may have a layer other than the substrate and the conductive layer.
The powder specific resistance of the conductive fine particles can be measured using, for example, an LCR meter (manufactured by Yokogawa Hewlett-Packard Company).
The powder specific resistance of the conductive fine particles is preferably 4 (Ω · cm) to 80 (Ω · cm), more preferably 4 (Ω · cm) to 20 (Ω · cm).

Regarding the setting of the carrier resistance, the prescription amount of the conductive fine particles is determined with respect to the target of the resistance value. However, when the powder specific resistance is less than 4 (Ω · cm), the prescription amount decreases, and The strength of the resin layer, which is a function of the conductive fine particles, is reduced and becomes brittle with stirring. If the prescription amount does not depend on the powder specific resistance, the resistance of the carrier naturally becomes low, and carrier adhesion is likely to occur. Lowering the powder specific resistance means an increase in the amount of conductive layer prescription, and the conductive fine particles also become larger, and the resin layer tends to be detached. Furthermore, it is fatal that the prescription amount is reduced also in the sense of controlling the important irregularities in the present invention.
A plurality of conductive fine particles having different powder specific resistances can be used in combination. For example, it is possible to use a method in which conductive fine particles having a low powder specific resistance and high conductive fine particles are used in combination so that the carrier resistance value does not depend on the prescribed amount. However, considering the above problem of separation, the powder specific resistance is preferably 4 (Ω · cm) or more.

On the other hand, if the specific resistance of the powder exceeds 80 (Ω · cm), the amount of prescription increases, so the dispersibility in the resin deteriorates and it exists as large conductive fine particles. Is likely to occur. If the prescription amount does not depend on the powder specific resistance, that is, if the prescription amount is not increased, the resistance of the carrier naturally becomes high, so that the problem of image quality is likely to occur.
When the resistance is increased, a so-called edge effect in which the density of the end portion becomes particularly high when black solid is printed becomes a problem. In addition to this, when printing an image having a black solid part in the halftone, an image in which the halftone part in the sheet passing direction is thinner than the black solid part (also referred to as a “hello image”). ). When the conductive layer is scraped or detached, the substrate is exposed and the carrier resistance is increased, such a halo image is likely to be generated.
The volume average particle size of the conductive fine particles is preferably 340 (nm) to 910 (nm). When the volume average particle size is less than 340 (nm), the particles are aggregated, and it becomes difficult to disperse into single particles. It is easy for people to leave. Further, the unevenness of the carrier surface is impaired, and it becomes difficult for the convex portion to scrape the so-called spent product derived from the toner adhering to the carrier surface.
On the other hand, even if the volume average particle size exceeds 910 (nm), it is not preferable because separation tends to occur.

---- Conductive layer ---
The conductive layer is preferably a conductive layer containing a certain amount of tin as a conductive material.
Until now, carbon black and ITO have been used as excellent resistance modifiers as conductive fine particles, but with the increase in speed of image forming devices, when carbon black is used, color stains under high stress, When ITO is used, there is a problem of resistance reduction due to film scraping after printing a large number of sheets.

Tin does not have the ability to adjust resistance as much as carbon black or ITO. For this reason, for example, when conductive fine particles are produced by coating a conductive material on a base of a conductive layer coating type, when ITO and tin are compared, the entire conductive fine particles have the same powder specific resistance. In addition, ITO needs to be used in small quantities, whereas tin must be used in large quantities. That is, when ITO is coated on the substrate, the conductive layer becomes a thin film, whereas tin has a thick conductive layer. Surprisingly, however, this results in an advantage in the present invention.
That is, the conductive fine particles using tin as a conductive material cannot avoid the peeling of the conductive layer due to the collision of carriers in the developing machine in the image forming apparatus, as the conductive fine particles using ITO. Since the film is thickened, the substrate is not exposed at an early stage. Specifically, it is possible to prevent the unevenness of the carrier surface from being changed by exposing the base portion.

For this reason, the carrier BET surface area can be easily maintained even after printing a large number of sheets without sharply progressing the shaving of the conductive layer of conductive fine particles.
Further, tin used in the present invention does not have a resistance adjusting ability as that of ITO, but can be reduced in electrical conductivity and reduced in resistance by reduction treatment.
Other conductive materials include doped products such as niobium, tantalum, antimony, and fluorine, but tin is preferable from a comprehensive viewpoint in terms of manufacturability, safety, and cost. More preferred is phosphorus-doped tin or tungsten-doped tin.

--- Substrate ---
The substrate is one or more selected from aluminum oxide, zinc oxide, and zirconium oxide (these are also referred to as “white inorganic pigments”).
For example, when aluminum oxide is used, the size of the conductive fine particles is not particularly limited. A shape such as a spherical shape or a needle shape can also be used. Furthermore, an anatase type or rutile type crystal system or amorphous system can be used.

In the present invention, the importance of using tin for the conductive layer in the conductive fine particles is as described above, but the selection of the substrate to be coated is also very important. In particular, we consider it important in the following two points.
The first is that the size can be adjusted. By providing a certain size, moderate unevenness can be given to the carrier surface, and when the toner component adheres to the carrier recess, it can be scraped off by the protrusion, thereby stabilizing the carrier surface state after printing a large number of sheets. The second point is good adhesion to the conductive layer, that is, the tin layer. Although the reason has not been clarified, if the compatibility with the conductive layer is poor, the tin layer peels off from the conductive fine particles at the time of manufacture, and the target carrier cannot be produced. This problem also occurs when stirring is performed in the developer container.

As a result of conducting numerous experiments on the above problems, the present inventors have found that the material used for the conductive fine particle substrate in the present invention needs to be selected from aluminum oxide, zinc oxide, and zirconium oxide. It came to recognition.
As described above, it is considered that the role of the substrate is to provide an appropriate size and to improve the adhesion with the conductive layer. From this point of view, the size of the substrate is preferably 150 (nm) to 1,000 (nm), although it depends on the prescription amount of tin.

--- Method for producing conductive fine particles ---
The conductive fine particles in the present invention can be produced by various methods. For example, a tin salt hydrate layer containing a hydrate of phosphorus or tungsten salt is uniformly deposited on the surface of a substrate (white inorganic pigment particles). The layer (conductive layer) covering the obtained substrate can be fired.

In order to uniformly deposit a tin salt hydrate layer containing a hydrate of phosphorus or tungsten salt on the surface of the substrate, for example, a phosphorus salt (for example, phosphorus pentoxide, POCl ₃ or the like) or a tungsten salt (for example, chloride) Tungsten, tungsten oxychloride, sodium tungstate, tungstate, etc., and tin compounds (for example, tin salts such as tin chloride, tin sulfate, tin nitrate, etc.), stannates such as sodium stannate, potassium stannate, tin, etc. PH adjusting agent for depositing and depositing an acidic aqueous liquid containing an organic tin compound such as an alkoxide on the substrate surface in the form of a hydrate with respect to the dropped phosphorus or tungsten and tin. (E.g., aqueous base solution) and simultaneously dropping into an aqueous solution in which the substrate is dispersed, so that the substrate is dissolved or surface-modified by acid or alkali. It can be done while preventing quality. At this time, the doping ratio of phosphorus or tungsten to SiO ₂ can be adjusted by adjusting the dropping amount of phosphorus or tungsten and the dropping amount of tin chloride solution. However, the isoelectric point of tin hydrate, that is, tin hydroxide or stannic acid, and the isoelectric point of phosphorus or Wangsten component are not necessarily the same, and their solubility at a specific pH is not necessarily different. Also note that.

  Further, for the purpose of alleviating the aggressiveness to the substrate during the dropping operation and the extreme hydration reaction of phosphorus, tungsten, and tin and homogenizing the layer (conductive layer) covering the substrate, for example, methanol or A water-soluble organic solvent such as methyl ethyl ketone can be mixed and used. The obtained hydrate is preferably fired at 300 ° C. to 850 ° C. in a non-oxidizing atmosphere. Thereby, compared with what heat-processed in the air, the volume specific resistance of electroconductive fine particles can be suppressed very low.

  The conductive fine particles may be subjected to a surface treatment. By performing such a treatment, the upper conductive layer can be fixed uniformly and firmly on the particle surface, so that the resistance adjusting effect can be sufficiently exhibited. For the surface treatment, an amino silane coupling agent, a methacryloxy silane coupling agent, a vinyl silane coupling agent, or a mercapto silane coupling agent can be used.

--Resin--
There is no restriction | limiting in particular as said resin, According to the objective, it can select suitably, For example, an acrylic resin, an amino resin, a silicone resin etc. are mentioned.
In the present invention, it is preferable to use a silicone resin.
In the present invention, it is important to give the carrier irregularities using conductive fine particles. Silicone resin is effective because the conductive fine particles are kept on the carrier surface. Also, it is preferable to use a silicone resin from the viewpoint of lowering the carrier surface energy and making the toner spent difficult.

  The silicone resin refers to all generally known silicone resins, and is not particularly limited and can be appropriately selected according to the purpose. For example, straight silicone consisting only of organosilosan bond, alkyd, Examples thereof include silicone resins modified with polyester, epoxy, acrylic, urethane and the like. For example, commercially available straight silicone resins include KR271, KR255, KR152 manufactured by Shin-Etsu Chemical, SR2400, SR2406, SR2410 manufactured by Toray Dow Corning Silicone. In this case, it is possible to use the silicone resin alone, but it is also possible to simultaneously use other components that undergo a crosslinking reaction, charge amount adjusting components, and the like. Further, commercially available modified silicone resins include KR206 (alkyd modified), KR5208 (acrylic modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical, SR2115 manufactured by Toray Dow Corning Silicone. Epoxy modified), SR2110 (alkyd modified) and the like.

Further, as the resin, a copolymer containing at least the A part represented by the following general formula (A) and the B part represented by the following general formula (B) is hydrolyzed to generate a silanol group for condensation. It is more preferable to use a resin containing a crosslinked product obtained by doing so.

In the general formula (A), ^{R 1} represents a hydrogen atom or a methyl group,, ^{R 2} represents an alkyl group having 1 to 4 carbon atoms, m is 1-8 integer X represents a molar ratio in the copolymer, and represents 10 mol% to 90 mol%.

However, the general formula (B), ^{R 1} represents a hydrogen atom or a methyl group, ^{R 2} represents an alkyl group having 1 to 4 carbon atoms, ^{R 3} is 1 to 8 carbon atoms It represents either an alkyl group or an alkoxy group having 1 to 4 carbon atoms, m represents an integer of 1 to 8, Y represents a molar ratio in the copolymer, and represents 10 mol% to 90 mol%. .

Although the reason has not been clarified, the CA1 value and the CA2 value can be effectively adjusted by using this resin in combination with a silicone resin. In the present invention, it is important to select a carrier exhibiting a desired CA1 value and CA2 value as a replenishment carrier or an initial carrier, so how to adjust the resin of this carrier is a very important factor. It is.
By using this resin, the increase in the carrier resistance can be further suppressed, and the effect of suppressing spent with the toner can be greatly enhanced.

Various resins may be used alone as the resin. However, since various effects described above can be expected, it is preferable to use a plurality of types of resins in combination.
In forming the crosslinked product, a condensation polymerization catalyst may be used.
Examples of the polycondensation catalyst include titanium-based catalysts, tin-based catalysts, zirconium-based catalysts, and aluminum-based catalysts. In the present invention, among these various catalysts, among titanium-based catalysts that exhibit excellent results, titanium is particularly preferable. Diisopropoxybis (ethyl acetoacetate) is more preferred as the catalyst. This is considered to be because the effect of promoting the condensation reaction of the silanol group is large and the catalyst is hardly deactivated.

As said acrylic resin, all the resin which has an acrylic component is pointed out, there is no restriction | limiting in particular and it can select suitably according to the objective. In addition, it is possible to use the acrylic resin alone, but it is also possible to use at least one other component that undergoes a crosslinking reaction at the same time.
Examples of other components that undergo a crosslinking reaction include amino resins and acidic catalysts.
As the acidic catalyst, any having a catalytic action can be used, and examples thereof include a catalyst having a reactive group such as a fully alkylated type, a methylol group type, an imino group type, and a methylol / imino group type.
The resin preferably contains a crosslinked product of an acrylic resin and an amino resin.
Thereby, fusion | melting of resin layers can be suppressed, maintaining moderate elasticity. Further, the chargeability of the amino resin has a high contribution to the CA1, and it is easy to adjust the balance between the CA1 and the CA2.

There is no restriction | limiting in particular as said amino resin, According to the objective, it can select suitably, For example, a melamine resin and a benzoguanamine resin are preferable at the point which improves the charge provision ability of a carrier. Further, when it is necessary to appropriately control the charge imparting ability of the carrier, at least one of melamine resin and benzoguanamine resin may be used in combination with another amino resin.
As the acrylic resin capable of crosslinking with the amino resin, those having at least one of a hydroxyl group and a carboxyl group are preferable. Thereby, adhesiveness with core material particle | grains or electroconductive fine particles can further be improved, and the dispersion stability of electroconductive fine particles can also be improved. At this time, the acrylic resin has a hydroxyl value of preferably 10 mgKOH / g or more, and more preferably 20 mgKOH / g or more.

In the present invention, the resin preferably contains a silane coupling agent.
Thereby, electroconductive fine particles can be disperse | distributed stably.

  There is no restriction | limiting in particular as said silane coupling agent, According to the objective, it can select suitably, For example, it is good that aminosilane effective as a charge control agent contains. Specifically, r- (2-aminoethyl) aminopropyltrimethoxysilane, r- (2-aminoethyl) aminopropylmethyldimethoxysilane, r-methacryloxypropyltrimethoxysilane, N-β- (N-vinyl) Benzylaminoethyl) -r-aminopropyltrimethoxysilane hydrochloride, r-glycidoxypropyltrimethoxysilane, r-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, r- Chloropropyltrimethoxysilane, hexamethyldisilazane, r-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, r-chloropropylmethyl Methoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, allyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, dimethyldiethoxysilane, 1,3-divinyltetramethyldisilazane And methacryloxyethyldimethyl (3-trimethoxysilylpropyl) ammonium chloride. Two or more of these may be used in combination.

  Commercially available silane coupling agents include AY43-059, SR6020, SZ6023, SH6020, SH6026, SZ6032, SZ6050, AY43-310M, SZ6030, SH6040, AY43-036, AY43-031, SH6062, Z-6911, and SZ6300. , SZ6075, SZ6079, SZ6083, SZ6070, SZ6072, Z-6721, AY43-004, Z-6187, AY43-021, AY43-043, AY43-040, AY43-047, Z-6265, AY43-204M, AY43-048 , Z-6403, AY43-206M, AY43-206E, Z6341, AY43-210MC, AY43-083, AY43-101, AY43-013, AY43-15 E, Z-6920, Z-6940 (manufactured by Dow Corning Toray Silicone Co., Ltd.).

  The addition amount of the silane coupling agent is preferably 0.1% by mass to 10% by mass with respect to the resin. When the addition amount of the silane coupling agent is less than 0.1% by mass, the adhesion between the core material particles or conductive fine particles and the resin is lowered, and the resin layer may fall off during long-term use. If it exceeds 10 mass%, toner filming may occur during long-term use.

<<< Toner >>>
The toner includes a binder resin and a colorant, and further includes other components as necessary.
The toner may be a monochrome toner or a color toner.
Further, the toner particles may contain a release agent for application to an oilless system in which toner fixing prevention oil is not applied to the fixing roller. Such toner generally tends to cause filming. However, since the carrier of the present invention described above can suppress filming, the developer of the present invention maintains good quality for a long time. can do.
In addition, color toners, particularly yellow toners, generally have a problem of color stains due to scraping of the carrier coating layer (resin layer). Can be suppressed.

The toner can be produced using a known method such as a pulverization method or a polymerization method. For example, when a toner is manufactured using a pulverization method, first, a melt-kneaded product obtained by kneading a toner material is cooled, pulverized, and classified to prepare base particles. Next, in order to further improve transferability and durability, an external additive is added to the base particles to produce a toner.
At this time, the apparatus for kneading the toner material is not particularly limited and can be appropriately selected depending on the purpose. For example, a batch type two roll, Banbury mixer, KTK type twin screw extruder (Kobe Steel Works) TEM type twin screw extruder (Toshiba Machine Co., Ltd.), twin screw extruder (KCK), PCM type twin screw extruder (Ikegai Iron Works), KEX type twin screw extruder (Kurimoto Iron Works) And a continuous twin-screw extruder such as a co-kneader (manufactured by Buss).

When the cooled melt-kneaded product is pulverized, it is roughly pulverized using a hammer mill, a rotoplex, etc., and then finely pulverized using a fine pulverizer using a jet stream or a mechanical pulverizer. be able to. In addition, it is preferable to grind | pulverize so that an average particle diameter may be 3-15 micrometers.
Furthermore, when classifying the pulverized melt-kneaded material, a wind classifier or the like is used. In addition, it is preferable to classify | categorize so that the average particle diameter of a base particle may be 5 micrometers-20 micrometers.
In addition, when an external additive is added to the base particle, the external additive adheres to the surface of the base particle while being pulverized by mixing and stirring using a mixer.

-Binder resin-
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, styrene and its substituted homopolymers, styrene copolymers, polymethyl methacrylate, polybutyl methacrylate , Polyvinyl chloride, polyvinyl acetate, polyethylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, polyacrylic acid, rosin, modified rosin, terpene resin, phenol resin, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, aromatic Based petroleum resins. Two or more of these may be used in combination.

Examples of the homopolymer of the styrene and the substituted product thereof include polystyrene, poly p-styrene, and polyvinyl toluene.
Examples of the styrene copolymer include styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer. Polymer, styrene-methacrylic acid copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene -Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid ester copolymer, etc. .

In particular, the binder resin considering pressure fixing includes, for example, polyolefin, olefin copolymer, epoxy resin, polyester, styrene-butadiene copolymer, polyvinyl pyrrolidone, methyl vinyl ether-maleic anhydride copolymer, maleic acid modified A phenol resin, a phenol modified terpene resin, etc. are mentioned.
Examples of the polyolefin include low molecular weight polyethylene and low molecular weight polypropylene.
As the olefin copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, styrene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, Examples thereof include ethylene-vinyl acetate copolymer and ionomer resin.
Two or more of these resins may be used in combination.

-Colorant-
The colorant (pigment or dye) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a yellow pigment, an orange pigment, a red pigment, a purple pigment, a blue pigment, a green pigment, and a black pigment. Is mentioned.
Examples of the yellow pigment include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, etc. Can be mentioned.
Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK and the like.
Examples of the red pigment include Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B and the like. It is done.

Examples of the purple pigment include Fast Violet B and Methyl Violet Lake.
Examples of the blue pigment include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC.
Examples of the green pigment include chrome green, chromium oxide, pigment green B, and malachite green lake.
Examples of the black pigment include azine dyes, metal salt azo dyes, metal oxides, and composite metal oxides. More specifically, carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline. Black.
Two or more of the above pigments may be used in combination.

-Other ingredients-
The toner may contain a release agent, a charge control agent, and an external additive.
The release agent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyolefin, fatty acid metal salt, fatty acid ester, paraffin wax, amide wax, polyhydric alcohol wax, silicone varnish, carna Uba wax, ester wax and the like can be mentioned.
Examples of the polyolefin include polyethylene and polypropylene.
Two or more of the release agents may be used in combination.
The charge control agent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, nigrosine, an azine dye having an alkyl group having 2 to 16 carbon atoms (see Japanese Examined Patent Publication No. 42-1627) ), Basic dyes, basic dye lake pigments, quaternary ammonium salts, dialkyltin compounds, dialkyltin borate compounds, guanidine derivatives, polyamine resins, metal complexes of monoazo dyes, salicylic acid, metal complexes, sulfonated copper phthalocyanine Examples include pigments, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds, and the like.

  Examples of the basic dye include C.I. I. Basic Yellow 2 (C.I. 41000), C.I. I. Basic Yellow 3, C.I. I. Basic Red 1 (C.I. 45160), C.I. I. Basic Red 9 (C.I. 42500), C.I. I. Basic Violet 1 (C.I. 42535), C.I. I. Basic Violet 3 (C.I. 42555), C.I. I. Basic Violet 10 (C.I. 45170), C.I. I. Basic Violet 14 (C.I. 42510), C.I. I. Basic Blue 1 (C.I. 42025), C.I. I. Basic Blue 3 (C.I. 51005), C.I. I. Basic Blue 5 (C.I. 42140), C.I. I. Basic Blue 7 (C.I. 42595), C.I. I. Basic Blue 9 (C.I. 52015), C.I. I. Basic Blue 24 (C.I. 52030), C.I. I. Basic Blue 25 (C.I. 52025), C.I. I. Basic Blue 26 (C.I. 44045), C.I. I. Basic Green 1 (C.I. 42040), C.I. I. Examples include Basic Green 4 (C.I. 42000).

  Examples of the quaternary ammonium salt include C.I. I. Solvent Black 8 (C.I. 26150), benzoylmethyl hexadecyl ammonium chloride, decyl trimethyl chloride, and the like.

Examples of the dialkyltin compound include a dibutyltin compound and a dioctyltin compound.
Examples of the polyamine resin include a vinyl polymer having an amino group and a condensation polymer having an amino group.

Examples of the metal complex salts of monoazo dyes include metal complex salts of monoazo dyes described in JP-B Nos. 41-20153, 43-27596, 44-6397, and 45-26478. Is mentioned.
Examples of the salicylic acid include salicylic acid described in JP-B-55-42752 and JP-B-59-7385.
Examples of the metal complex include dialkyl salicylic acid, naphthoic acid, and dicarboxylic acid Zn, Al, Co, Cr, and Fe.

  Two or more of the charge control agents may be used in combination. For color toners other than black, it is preferable to use a metal salt of a white salicylic acid derivative.

There is no restriction | limiting in particular as said external additive, According to the objective, it can select suitably, For example, an inorganic particle, a resin particle, etc. are mentioned.
Examples of the inorganic particles include silica, titanium oxide, alumina, silicon carbide, silicon nitride, and boron nitride.
Examples of the resin particles include polymethyl methacrylate particles and polystyrene particles having an average particle size of 0.05 μm to 1 μm obtained by a soap-free emulsion polymerization method.
Two or more external additives may be used in combination.
Among these, metal oxide particles such as silica and titanium oxide whose surfaces are hydrophobized are preferable. In addition, when the hydrophobized silica and hydrophobized titanium oxide are used in combination, the amount of added hydrophobized titanium oxide is higher than the hydrophobized silica. Thus, a toner having excellent charge stability with respect to the toner can be obtained.

<Transfer means and transfer process>
The transfer unit is not particularly limited as long as it is a unit that transfers the toner image formed on the electrostatic latent image carrier to a recording medium, and can be appropriately selected according to the purpose. For example, a method of directly transferring a toner image from the surface of the electrostatic latent image carrier to a recording medium, and using an intermediate transfer member, the toner image is primarily transferred onto the intermediate transfer member, and then the toner image is transferred to the recording medium. There is a secondary transfer method above.
The transfer step is a step of transferring the toner image formed on the electrostatic latent image carrier to a recording medium.
Examples of the transfer device used for the transfer means include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

<Other means and other processes>
The image forming apparatus of the present invention may include a fixing unit, a cleaning unit, a charge eliminating unit, a recycling unit, a control unit, and the like as necessary.
The image forming method of the present invention may include a fixing step, a cleaning step, a charge removal step, a recycling step, a control step, and the like as necessary.

<< Fixing means >>
The fixing unit is not particularly limited as long as it is a unit that fixes the toner image transferred to the recording medium, and can be appropriately selected according to the purpose. For example, a known heating and pressing unit is used. be able to. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller, and an endless belt. The heating in the heating and pressing means is preferably 80 ° C to 200 ° C. In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing unit depending on the purpose.
In the fixing, the toner of each color may be transferred to the recording medium for each color, or may be transferred at once in a state where the toner of each color is laminated.

<Embodiment of Image Forming Apparatus>
An image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, first, the electrostatic latent image carrier 20 is rotationally driven at a predetermined peripheral speed, and the peripheral surface of the electrostatic latent image carrier 20 is set to a positive or negative predetermined potential by the charging device 32. Uniformly charged. Next, the peripheral surface of the electrostatic latent image carrier 20 is exposed by the exposure device 33, and electrostatic latent images are sequentially formed. Further, the electrostatic latent image formed on the peripheral surface of the electrostatic latent image carrier 20 is developed by the developing device 40 using the developer containing the carrier and the toner of the present invention to form a toner image. Next, the toner image formed on the peripheral surface of the electrostatic latent image carrier 20 is synchronized with the rotation of the electrostatic latent image carrier 20, and the electrostatic latent image carrier 20 and the transfer device 50 are fed from the paper feeding unit. The images are sequentially transferred onto the transfer paper fed during the period. Further, the transfer paper onto which the toner image has been transferred is separated from the peripheral surface of the electrostatic latent image carrier 20, introduced into the fixing device and fixed, and then copied to the outside of the image forming apparatus 100. Printed out. On the other hand, after the toner image is transferred, the surface of the electrostatic latent image carrier 20 is cleaned by the cleaning device 60 after the remaining toner is removed, and then the static electricity is removed by the static eliminator 70 to repeatedly form images. used.

  The developing device 40 will be described in more detail. The developing device 40 includes a developer container and a replenishment cartridge. The replenishment developer composed of the replenishment carrier and the toner in the replenishment cartridge is replenished to the developer accommodating portion by the replenishment means. Before the replenishment developer is replenished, an initial developer composed of an initial carrier and toner is accommodated in the developer accommodating portion. Before the replenishment developer is replenished, a toner image is formed by the initial developer. The initial developer is replaced by a replenishing developer that is replenished as needed. Excess developer in the developer container is appropriately recovered by the recovery member described above. In particular, the toner is consumed and reduced, but the carrier is not consumed and remains in the developer accommodating portion. Therefore, the above-described collecting member functions effectively for collecting the deteriorated carrier. Thus, the initial carrier is replaced with a replenishment carrier as needed. Then, a toner image is formed by the developer replaced as needed.

(Process cartridge)
The process cartridge of the present invention includes the developer containing the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier, the developer including the carrier and the toner. The developing means that develops using the developer contained in the section and forms a toner image is integrally supported.
The carrier has at least one of an initial carrier and a replenishment carrier.
The developing means includes the replenishment member that replenishes the developer storage unit with the replenishment developer from the replenishment cartridge having the replenishment developer including at least the replenishment carrier. .
The process cartridge of the present invention includes the developer of the present invention, and can be detachably provided in various electrophotographic image forming apparatuses, facsimiles, and printers, and is detachably provided in the image forming apparatus of the present invention. More preferably.

<Embodiment of Process Cartridge>
An embodiment of the process cartridge of the present invention will be described with reference to FIG.
The process cartridge (10) includes a photosensitive member (11) as an electrostatic latent image carrier, a charging device (12) for charging the photosensitive member (11), and an electrostatic latent image formed on the photosensitive member (11). A developing device (13) that develops using a developer containing a carrier and a toner of the present invention to form a toner image, and a toner image formed on the photoreceptor (11) is transferred to a recording medium, and then the photoreceptor. (11) A cleaning device (14) for removing toner remaining on the surface is integrally supported, and the process cartridge (10) is detachable from a main body of an image forming apparatus such as a copying machine or a printer.
The process cartridge according to the present invention develops the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier using the developer containing the carrier and toner of the present invention. The developing means for forming the toner image is at least integrally supported. Therefore, the process cartridge according to the present invention is not necessarily provided for the other configurations described above.

  Hereinafter, a method for forming an image using the image forming apparatus equipped with the process cartridge (10) will be described. First, the photosensitive member (11) is rotationally driven at a predetermined peripheral speed, and the charging device (12) uniformly charges the peripheral surface of the photosensitive member (11) to a predetermined positive or negative potential. Next, exposure light is irradiated onto the peripheral surface of the photoreceptor (11) from an exposure apparatus (not shown) such as a slit exposure type exposure apparatus or an exposure apparatus that performs scanning exposure with a laser beam, and electrostatic latent images are sequentially formed. The Further, the electrostatic latent image formed on the peripheral surface of the photoconductor (11) is developed by the developing device (13) using the developer containing the carrier and toner of the present invention to form a toner image. Next, the toner image formed on the peripheral surface of the photoconductor (11) is synchronized with the rotation of the photoconductor (11), and the photoconductor (11) and the transfer device (not shown) are fed from the paper feed unit (not shown). ) Are sequentially transferred onto a transfer sheet which is a recording medium fed during (). Further, the transfer paper onto which the toner image has been transferred is separated from the peripheral surface of the photoreceptor (11), introduced into a fixing device (not shown) and fixed, and then copied as a copy (copy) of the image forming apparatus. Printed out. On the other hand, after the toner image is transferred, the surface of the photoconductor (11) is cleaned by the cleaning device (14) to remove the remaining toner, and then the charge is removed by a static eliminator (not shown). Used for image formation.

<Example of production of core particles>
MnCO ₃ , Mg (OH) ₂ , and Fe ₂ O ₃ powder were weighed and mixed to obtain a mixed powder. This mixed powder was calcined in a heating furnace at 900 ° C. for 3 hours in an air atmosphere, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle diameter of about 7 μm. This powder was made into a slurry by adding 1 wt% dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having a volume average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1,250 ° C. for 5 hours in a nitrogen atmosphere.
The obtained fired product was pulverized with a pulverizer, and then the particle size was adjusted by sieving to obtain spherical ferrite particles C1 [core material particles 1] having a volume average particle size of about 35 μm.
The volume average particle size is set to a material refractive index of 2.42, a solvent refractive index of 1.33, and a concentration of about 0.06 in water using a Microtrac particle size distribution model HRA9320-X100 (manufactured by Nikkiso Co., Ltd.). Measured.

<Synthesis of copolymer>
The weight average molecular weight was determined in terms of standard polystyrene using gel permeation chromatography. The viscosity was measured at 25 ° C. according to JIS-K2283. The nonvolatile content was calculated according to the following formula by weighing 1 g of the coating composition in an aluminum dish and measuring the mass after heating at 150 ° C. for 1 hour.
Nonvolatile content (%) = (mass before heating−mass after heating) × 100 / mass before heating

300 g of toluene was charged into a flask equipped with a stirrer, and the temperature was raised to 90 ° C. under a nitrogen gas stream.
Then this
84.4 g of ₃ -methacryloxypropyltris (trimethylsiloxy) silane represented by CH ₂ = CMe—COO— (C ₃ H ₆ ) —Si (OSiMe ₃ ) ₃ (wherein Me is a methyl group) 200 mmol) (Silaplane TM-0701T / manufactured by Chisso Corporation), 39 g (150 mmol) of 3-methacryloxypropylmethyldiethoxysilane, 65.0 g (650 mmol) of methyl methacrylate, and 2,2′-azobis A mixture of 0.58 g (3 mmol) of 2-methylbutyronitrile was added dropwise over 1 hour.
After completion of the dropwise addition, a solution prepared by dissolving 0.06 g (0.3 mmol) of 2,2′-azobis-2-methylbutyronitrile in 15 g of toluene was further added (2,2′-azobis-2-methylbutyrate). The total amount of rhonitrile (0.64 g = 3.3 mmol) was mixed at 90 ° C. to 100 ° C. for 3 hours and radical copolymerized to obtain a methacrylic copolymer 1.
The resulting methacrylic copolymer 1 had a weight average molecular weight of 33,000.
Subsequently, it diluted with toluene so that the non volatile matter of this methacrylic copolymer solution might be 25 mass%. The viscosity of the copolymer solution thus obtained was 8.8 mm ² / s, and the specific gravity was 0.91.

<Manufacture of conductive fine particles>
Next, an example of producing conductive fine particles is shown. For the substrate, a general commercial product was used, but fine experiments were made possible by changing the particle size using an airflow classifier or the like.

-Production Example 1-
100 g of a powder having a volume average particle diameter of 300 nm, in which the particle size distribution of aluminum oxide (AKP-30 manufactured by Sumitomo Chemical Co., Ltd.) was adjusted, was dispersed in 1 liter of water to form a suspension, and this liquid was heated to 65 ° C. To this suspension, a solution obtained by dissolving 130 g of stannic chloride and 3.9 g of phosphorus pentoxide in 1 liter of 2N hydrochloric acid and 12% by mass of ammonia water for 156 minutes so that the pH of the suspension is 7-8. It was dripped over. After dropping, the cake obtained by filtering and washing the suspension was dried at 110 ° C.
Next, this dry powder was treated in a nitrogen stream at 500 ° C. for 1 hour to obtain [Conductive Fine Particles 1] having a volume average particle size of 570 nm and a powder specific resistance of 9 Ω · cm.
The volume average particle diameter was measured using Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.) in water with a material refractive index of 1.66 and a solvent refractive index of 1.33.
The powder specific resistance of the conductive fine particles was converted to a specific resistance by compressing and molding the sample powder at 250 kg / cm ² , measuring the electrical resistance value using an LCR meter manufactured by Yokogawa Hewlett-Packard Company.
Details are shown in Table 1.

-Production Examples 2-5
In the production example 1 of the conductive fine particles, the conductive particles were obtained in the same manner as the conductive fine particles 1 except that the particle size of the substrate, the prescribed amounts of stannic chloride and phosphorus pentoxide, and the dropping fraction were changed as shown in Table 1. Fine particles were obtained. Details are given in Table 1.

-Production Example 6
In Production Example 1 of conductive fine particles, commercially available zinc oxide (manufactured by Teika Co., Ltd.) was classified and used. Conductive fine particles were obtained in the same manner as the conductive fine particles 1 except that the type of the substrate, the prescription amounts of stannic chloride and phosphorus pentoxide, and the dropping fraction were changed as shown in Table 1. Details are given in Table 1.

<Carrier manufacturing>
-Manufacture of carrier A-
[Carrier resin layer formulation]
-Methacrylic copolymer 1 [solid content 25% by mass] 109.0 parts by mass-Silicone resin solvent [solid content 20% by mass]
(SR2410: manufactured by Toray / Dow Corning / Silicone) 517.0 parts by mass / aminosilane [solid content: 100% by mass]
(SH6020: manufactured by Toray Dow Corning Silicone Co., Ltd.) 14.2 parts by mass, conductive fine particles 1 156.0 parts by mass, toluene 750.0 parts by mass

  The carrier resin layer formulation was dispersed together with 1,000 parts by mass of 0.5 mm Zr beads with a paint shaker for 1 hour, then the beads were removed with a mesh and allowed to stand for 10 minutes to obtain a resin layer forming solution. [Core material particle 1] described above as a core material: 5,000 parts by mass, and 31.3 parts by mass of TC-750 (manufactured by Matsumoto Fine Chemical Co., Ltd.) [solid content 60% by mass] were added to the resin layer forming solution. The solution was applied to the surface of the core material particles with a Spira coater (Okada Seiko Co., Ltd.) at a coater internal temperature of 65 ° C. and dried. The obtained carrier was baked by standing in an electric furnace at 250 ° C. for 1 hour in a nitrogen atmosphere. After cooling, the ferrite powder bulk was pulverized using a sieve having an aperture of 63 μm to obtain [Carrier A].

For this carrier A, the CA1 and CA2 values were measured by the method described above.
That is, in a stainless steel container having a diameter of 2.5 cm and a height of 3.0 cm, carrier 9.0 g and toner (hereinafter, toner for digital full color printer (RICOH Pro C901, manufactured by Ricoh Co., Ltd.) used in the examples) 0.678 g Was introduced. This container was set in a tumbler mixer (manufactured by Glen Mills) together with an appropriate spacer and stirred at 67 rpm.
The CA1 value and CA2 value of the sample stirred for 1 minute and the sample stirred for 10 minutes were measured using a blow-off device disclosed in JP-A-08-313487. As described above, the measurement conditions are in accordance with [Example / Operation Example 3] in Japanese Patent Application Laid-Open No. 08-313487, except that the mesh is changed from # 635 to # 795 (mesh size 16 μm, wire diameter 16 μm, space factor 25%). It was. The height setting values were set in three stages, h1 = 55 h2 = 0 h3 = 0, the suction pressures were set to 100 for P1, P2, and P3, and the measurement was carried out with 0.30 g of developer. The measurement environment was measured at 23 ° C. and 50% RH.
The results of CA1 value and CA2 value are shown in Table 2.

-Manufacture of carriers B-S-
In the production of carrier A, methacrylic copolymer 1 [solid content 25% by mass], silicone resin solution [solid content 20% by mass], prescription amount of aminosilane [solid content 100% by mass] and conductive fine particles Manufactured in the same manner as Carrier A, except that the amount was changed as shown in Table 2.
Table 2 shows the prescription amounts of the carriers B to S and the results of the CA1 value and the CA2 value measured in the same manner as the carrier A.

Example 1
A developer was prepared as follows.
Carrier B (930 parts by mass) obtained by the above carrier manufacturing method and a commercially available digital full color printer (RICOH Pro C901, manufactured by Ricoh Co., Ltd.) toner (70 parts by mass) are mixed, and a turbuler mixer is used. The mixture was stirred at 67 rpm for 3 minutes to prepare an initial developer. Further, the developer for replenishment is a ratio of 100 parts by mass of carrier and 900 parts by mass of toner using carrier A obtained by the carrier production method and the toner (the toner concentration is 90% by mass in the developer for replenishment) The developer for replenishment was prepared. In this experiment, all were performed in cyan.
Using these developers, they are set in a commercially available digital full-color printer (RICOH Pro C901, manufactured by Ricoh Co., Ltd.), and a character chart (size of one character; 2 mm × 2) with an output of 75% per minute and an image area of 8% One sheet of about 2 mm) was printed, and the background stain evaluation shown below was performed. Furthermore, 110,000 sheets were continuously printed, and the background smudge evaluation and the following character blur evaluation were performed. The results are shown in Table 3.

[Earth dirt evaluation]
Blank paper printing (image area 0%) was performed at the time of the corresponding number of sheets, and ID measurement was performed. For the ID measurement, an average of three measurements of center, rear, and front was measured by X-Rite 938 (manufactured by X-Rite), and the difference from the original blank paper was ranked as ΔID.
“◎: Extremely good”, “◎: Very good”, “◯: Good”, “△: Acceptable level” was accepted, and “×: Unusable level for practical use” was rejected.
-Evaluation criteria-
◎◎: 0.01 ≧ △ ID
A: 0.01 <ΔID ≦ 0.02
○: 0.02 <ΔID ≦ 0.03
Δ: 0.03 <ΔID ≦ 0.06
×: 0.06 <△ ID

[Character blurring evaluation]
Black printing (image area 100%) was performed on the 110,000th sheet, and ID measurement was performed. The ID was also measured in the same manner as the above-mentioned background stain, and was classified into the following ranks.
“◎: Extremely good”, “◎: Very good”, “◯: Good”, “△: Acceptable level” was accepted, and “×: Unusable level for practical use” was rejected.
-Evaluation criteria-
◎◎: 0.02 ≧ △ ID
A: 0.02 <ΔID ≦ 0.04
○: 0.04 <ΔID ≦ 0.10
Δ: 0.10 <ΔID ≦ 0.20
×: 0.20 <△ ID

(Examples 2 to 16)
In Example 1, except that the replenishment carrier was changed as shown in Table 3 to produce a replenishment developer, and the initial carrier was changed as shown in Table 3 to produce and use an initial developer. Evaluation was conducted in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Examples 1-7)
In Example 1, except that the replenishment carrier was changed as shown in Table 3 to produce a replenishment developer, and the initial carrier was changed as shown in Table 3 to produce and use an initial developer. Evaluation was conducted in the same manner as in Example 1. The results are shown in Table 3.
In Comparative Example 7, a replenishment developer and an initial developer were prepared and carried out using a carrier in which equal amounts of carrier A and carrier B were mixed.

In Comparative Examples 1 and 2, the picture became thin after printing about 50,000 to 50,000 sheets, and this was a problem.
In Comparative Example 3, the background stain was deteriorated when 10,000 sheets were printed.
In Comparative Example 4, scumming was already generated when 1000 sheets were printed. Also, the toner contamination around the developing device was the most severe in the experiment.
In Comparative Examples 5, 6, and 7, the picture was thin when 1000 sheets were printed.
Based on the above, the effects of stirring are grasped at two levels of weak stirring hazard and strong stirring hazard, and the initial carrier and replenishment carrier showing the relationship between the desired CA1 value and CA2 value are adjusted. However, it has been found that problems due to a decrease in charge of the carrier due to toner spent accumulation can be reduced.
It was also found that high-definition and high-quality images without image density fluctuations, background stains, and text blurring can be formed even in various usage environments by suppressing charging environmental fluctuations.
Further, there is no in-machine contamination due to toner scattering, and a highly reliable image forming apparatus can be provided.

Aspects of the present invention are as follows, for example.
<1> an electrostatic latent image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier;
The electrostatic latent image formed on the electrostatic latent image carrier is developed using the developer contained in a developer containing portion having a developer containing a carrier and toner to form a toner image. Developing means;
An image forming apparatus having transfer means for transferring the toner image formed on the electrostatic latent image carrier to a recording medium,
The carrier has at least one of an initial carrier and a replenishment carrier;
The developing means includes a replenishing member that replenishes the developer accommodating portion with the replenishment developer from a replenishment cartridge having a replenishment developer including at least the replenishment carrier;
When the replenishment carrier and the toner are stirred using a tumbler mixer at 67 rpm for 1 minute, the charge amount of the replenishment carrier is CA1-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a tumbler mixer is CA1-2 (μC / g), CA1-1 is 8 (μC / g) from CA1-2. g) to 20 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 6 (μC of the CA2-2. / G), the image forming apparatus.
<2> The charge amount of the replenishment carrier when the replenishment carrier and the toner are stirred at 67 rpm for 1 minute using a tumbler mixer is CA1-1 (μC / g). When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a tumbler mixer is CA1-2 (μC / g), the CA1-1 is 10 (μC / g) than the CA1-2. g) to 15 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 4 (μC of the CA2-2. / G), the image forming apparatus according to <1>.
<3> The replenishment carrier and the initial carrier include a core material particle having magnetism and a resin layer covering the surface of the core material particle, and the resin layer contains at least aminosilane. To <2>.
<4> The resin layer of the replenishment carrier and the initial carrier hydrolyzes a copolymer containing at least an A portion represented by the following general formula (A) and a B portion represented by the following general formula (B). The image forming apparatus according to <3>, wherein the image forming apparatus contains a cross-linked product obtained by decomposition, generation of a silanol group, and condensation.

In the general formula (A), ^{R 1} represents a hydrogen atom or a methyl group,, ^{R 2} represents an alkyl group having 1 to 4 carbon atoms, m is 1-8 integer X represents a molar ratio in the copolymer, and represents 10 mol% to 90 mol%.

In the general formula (B), ^{R 1} represents a hydrogen atom or a methyl group,, ^{R 2} represents an alkyl group having 1 to 4 carbon atoms, ^{R 3} is 1 to 8 carbon atoms Or an alkyl group having 1 to 4 carbon atoms, m represents an integer of 1 to 8, Y represents a molar ratio in the copolymer, and is 10 mol% to 90 mol%. Represents.
<5> an electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier;
A development step of developing the electrostatic latent image formed on the electrostatic latent image carrier using a developer containing a carrier and toner, which is accommodated in a developer accommodating portion, and forming a toner image;
A transfer step of transferring the toner image formed on the electrostatic latent image carrier to a recording medium,
The carrier has at least one of an initial carrier and a replenishment carrier;
The developing step includes a replenishment process for replenishing the developer container with a replenishment developer including at least the replenishment carrier from a replenishment cartridge;
When the replenishment carrier and the toner are stirred using a tumbler mixer at 67 rpm for 1 minute, the charge amount of the replenishment carrier is CA1-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a tumbler mixer is CA1-2 (μC / g), CA1-1 is 8 (μC / g) from CA1-2. g) to 20 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 6 (μC of the CA2-2. / G), the image forming method.
<6> an electrostatic latent image carrier;
The electrostatic latent image formed on the electrostatic latent image carrier is developed using the developer contained in a developer containing portion having a developer containing a carrier and toner to form a toner image. The developing device is a process cartridge that is integrally supported,
The carrier has at least one of an initial carrier and a replenishment carrier;
The developing means includes a replenishing member that replenishes the developer accommodating portion with the replenishment developer from a replenishment cartridge having a replenishment developer including at least the replenishment carrier;
When the replenishment carrier and the toner are stirred using a tumbler mixer at 67 rpm for 1 minute, the charge amount of the replenishment carrier is CA1-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a tumbler mixer is CA1-2 (μC / g), CA1-1 is 8 (μC / g) from CA1-2. g) to 20 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 6 (μC of the CA2-2. / G) of the process cartridge.

DESCRIPTION OF SYMBOLS 1a Electrode 1b Electrode 2 Fluororesin container 3 Electrostatic latent image developing carrier 10 Process cartridge 11 Electrostatic latent image carrier 12 Charging device 13 Developing device 14 Cleaning device 20 Electrostatic latent image carrier 32 Charging device 33 Exposure device 40 Developing device 50 Transfer device 60 Cleaning device 70 Static elimination device 100 Image forming device

Japanese Patent No. 3562285 Japanese Patent No. 3777778 Japanese Patent No. 4504653

Claims (6)

An electrostatic latent image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier;
The electrostatic latent image formed on the electrostatic latent image carrier is developed using the developer contained in a developer containing portion having a developer containing a carrier and toner to form a toner image. Developing means;
An image forming apparatus having transfer means for transferring the toner image formed on the electrostatic latent image carrier to a recording medium,
The carrier has at least one of an initial carrier and a replenishment carrier;
The developing means includes a replenishing member that replenishes the developer accommodating portion with the replenishment developer from a replenishment cartridge having a replenishment developer including at least the replenishment carrier;
When the replenishment carrier and the toner are stirred using a tumbler mixer at 67 rpm for 1 minute, the charge amount of the replenishment carrier is CA1-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a tumbler mixer is CA1-2 (μC / g), CA1-1 is 8 (μC / g) from CA1-2. g) to 20 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 6 (μC of the CA2-2. / G), the image forming apparatus. The charge amount of the replenishment carrier when the replenishment carrier and toner are stirred at 67 rpm for 1 minute using a tumbler mixer is set to CA1-1 (μC / g), and the initial carrier and the toner are When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a blur mixer is CA1-2 (μC / g), the CA1-1 is 10 (μC / g) to CA1-2. 15 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 4 (μC of the CA2-2. / G) or less.   The replenishment carrier and the initial carrier are each composed of a magnetic core material particle and a resin layer covering the surface of the core material particle, and the resin layer contains at least aminosilane. An image forming apparatus according to claim 1. The resin layer of the replenishment carrier and the initial carrier hydrolyzes a copolymer containing at least the A part represented by the following general formula (A) and the B part represented by the following general formula (B), The image forming apparatus according to claim 3, comprising a cross-linked product obtained by generating and condensing a silanol group.

In the general formula (A), ^{R 1} represents a hydrogen atom or a methyl group,, ^{R 2} represents an alkyl group having 1 to 4 carbon atoms, m is 1-8 integer X represents a molar ratio in the copolymer, and represents 10 mol% to 90 mol%.

In the general formula (B), ^{R 1} represents a hydrogen atom or a methyl group,, ^{R 2} represents an alkyl group having 1 to 4 carbon atoms, ^{R 3} is 1 to 8 carbon atoms Or an alkyl group having 1 to 4 carbon atoms, m represents an integer of 1 to 8, Y represents a molar ratio in the copolymer, and is 10 mol% to 90 mol%. Represents. An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier;
A development step of developing the electrostatic latent image formed on the electrostatic latent image carrier using a developer containing a carrier and toner, which is accommodated in a developer accommodating portion, and forming a toner image;
A transfer step of transferring the toner image formed on the electrostatic latent image carrier to a recording medium,
The carrier has at least one of an initial carrier and a replenishment carrier;
The developing step includes a replenishment process for replenishing the developer container with a replenishment developer including at least the replenishment carrier from a replenishment cartridge;
When the replenishment carrier and the toner are stirred using a tumbler mixer at 67 rpm for 1 minute, the charge amount of the replenishment carrier is CA1-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a tumbler mixer is CA1-2 (μC / g), CA1-1 is 8 (μC / g) from CA1-2. g) to 20 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 6 (μC of the CA2-2. / G), the image forming method. An electrostatic latent image carrier;
The electrostatic latent image formed on the electrostatic latent image carrier is developed using the developer contained in a developer containing portion having a developer containing a carrier and toner to form a toner image. The developing device is a process cartridge that is integrally supported,
The carrier has at least one of an initial carrier and a replenishment carrier;
The developing means includes a replenishing member that replenishes the developer accommodating portion with the replenishment developer from a replenishment cartridge having a replenishment developer including at least the replenishment carrier;
When the replenishment carrier and the toner are stirred using a tumbler mixer at 67 rpm for 1 minute, the charge amount of the replenishment carrier is CA1-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 1 minute at 67 rpm using a tumbler mixer is CA1-2 (μC / g), CA1-1 is 8 (μC / g) from CA1-2. g) to 20 (μC / g) higher,
The charge amount of the replenishment carrier when the replenishment carrier and the toner were stirred for 10 minutes at 67 rpm using a tumbler mixer was CA2-1 (μC / g), and the initial carrier and the toner When the charge amount of the initial carrier when stirring for 10 minutes at 67 rpm using a tumbler mixer is CA2-2 (μC / g), the CA2-1 is ± 6 (μC of the CA2-2. / G), a process cartridge characterized by