JP5321164B2 - Electrophotographic developer supply method, electrophotographic developing apparatus, electrophotographic developing method, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably maintain physical properties of a carrier in a developing device in a developing system using a two-component developer, to control a toner concentration of the developer supplied to the developing device to a fixed value while suppressing the occurrence of faults such as the rise of image density and fogging regardless of a long-time use, and to enhance the handling accuracy of the toner concentration of the developer in the developing device to be able to accurately control the toner concentration of the developer in the developing device. <P>SOLUTION: In a trickle development system where a toner and a carrier are replenished to a developing device and development is performed while discharging a surplus developer in the developing device, a mass ratio of the carrier in a developer for replenishment which is replenished to a developing device 10 is detected, and the mass ratio is compared with a mass ratio of the carrier in the developer for replenishment stored in a container 230 of the developer for replenishment, and in the case that the mass ratios are different, a mechanism for reducing the deviation of the toner concentration of the developer for replenishment stored in the container 230 is operated to make the toner concentration uniform in the container 230. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an electrophotographic developer supply method, an electrophotographic developing apparatus, an electrophotographic developing method, and a process cartridge in electrophotography.

In an electrophotographic image forming apparatus such as a copying machine or a printer, a uniformly charged image carrier surface is exposed to form a latent image, and the latent image is developed into a toner image. Transferred onto a transfer material such as recording paper. The transfer material carrying the toner image passes through the fixing device and fixes the toner on the transfer material by heat or pressure.
In the image forming apparatus, the developing device that develops the latent image on the image carrier includes a one-component developing type that develops using toner containing a magnetic material, and a developer composed of toner and carrier. There are two-component development systems that perform development.
Among them, the two-component developing type developing device is excellent in developability, and is currently the mainstream of image forming apparatuses. In particular, in recent years, it has been widely used in color image forming apparatuses that form full-color and multi-color images, and the demand for two-component developing type developing apparatuses is further increasing.
In the two-component developing type image forming apparatus, the toner and the carrier are agitated in the developing device, and the toner is given a charge from the carrier by friction. The toner is electrostatically attached to the outer surface of the carrier, and the carrier carrying the toner is conveyed to the development area. Under the condition that the development bias is applied, the toner is separated from the carrier, and electrostatically adheres to the latent image portion of the image carrier to form a toner image. In the two-component development method, in order to provide a highly durable image satisfying high stability, it is important that a stable charge amount is imparted to the toner from the carrier during stirring. It is important that the charge imparting ability of the carrier is stable before and after long-time use.
However, in the developing device in the normal two-component developing system, the toner is consumed by the developing operation, while the carrier is not consumed and remains in the developing tank. Therefore, the carrier stirred together with the toner in the developing tank deteriorates as the stirring frequency increases. Specifically, a situation such as peeling of the resin coat on the carrier surface or adhesion of toner to the carrier surface occurs, and as a result, the carrier resistance value and the chargeability of the developer gradually decrease, and the developer developability. Rises excessively, causing problems such as an increase in image density and occurrence of fogging.

As a solution to the above problem, for example, in Patent Document 1, a carrier is added together with toner consumed by development, and the carrier in the developing device is replaced little by little, thereby suppressing a change in charge amount and image density. Has been disclosed, a so-called trickle developing type developing device.
However, when the carrier replenishing device and the toner replenishing device are integrated in the developing device disclosed in Patent Document 1, the mass ratio of the toner in the container in which the carrier and the toner are mixed and accommodated as a replenishing developer. If there is a bias in the toner density (hereinafter referred to as toner density), the developer replenished to the developing device may be more toner or carrier than the intended toner density, making it difficult to handle the toner density in the developing device. Become. If the handling accuracy of the toner density in the developing device is low, the toner density in the developing device will be higher than the appropriate state, causing toner scattering and charging unevenness, or being lower than the appropriate state, resulting in excessive charging. This is not preferable because it may cause insufficient concentration.
Japanese Patent Application Laid-Open No. 2004-228561 discloses using a developer containing a carrier having a higher resistance value than that of a carrier previously stored in the developing device as a developer to be replenished appropriately in the developing device. .
Further, in Patent Document 3, as a replenishment developer, a developer containing a carrier that imparts a higher charge amount to the toner together with the toner is used to maintain the chargeability and suppress the deterioration of the image quality. It is disclosed.
These methods are methods that maintain the chargeability with the physical properties of the replenishment developer and suppress the deterioration of image quality, but consider the variation in the concentration of toner to be replenished each time due to the concentration deviation of the replenishment developer. It has not been done, and it cannot be a countermeasure against the aforementioned problems.

The present invention has been made in view of the above-described problems of the prior art,
In two-component development type image formation, the physical properties of the carrier in the developing device are kept stable, and even in long-term use, the image density is increased and the occurrence of problems such as fogging is suppressed, and the developer is accommodated in a developer container. By reducing the bias in the toner concentration of the developer for replenishment, the toner concentration of the developer replenished to the developing device is controlled to be constant, and the handling accuracy of the toner concentration of the developer in the developing device is improved. It is an object of the present invention to provide a developer replenishing method capable of controlling the toner concentration of the developer in the developing device with high accuracy.

  The present inventors have intensively studied to solve the above problems. As a result, in order to prevent the occurrence of a defective image due to the deteriorated developer, the toner and the carrier are supplied to the developing device with respect to the developing device containing the toner and the carrier, In the trickle development method in which development is performed while discharging excess developer, the toner concentration of the developer supplied to the developing device is made constant, and the toner concentration of the developer in the developing device is controlled with high accuracy. The mass ratio of the carrier in the replenishment developer supplied to the developing device is detected, and this mass ratio is compared with the mass ratio of the carrier of the replenishment developer accommodated in the replenishment developer container. Based on the comparison result, the technical concept of controlling the operation of the mechanism for reducing the deviation of the toner density of the replenishment developer accommodated in the replenishment developer accommodating container was obtained, and the present invention was achieved.

That is, the following problems are solved by the following inventions 1 to 7 .
1. Using an electrophotographic developer carrier composed of core material particles and a coating layer covering the particles and a toner, a replenishment developer composed of toner and carrier is replenished to the developing device containing the toner and the carrier. In the electrophotographic developer replenishing method using the developer replenishing device that replenishes the developing device from the developer storage container and discharges the excess developer in the developing device, the developer replenishing device includes: The replenishment developer storage container is detachably provided, the replenishment developer storage container is filled with the replenishment developer, the replenishment developer is sucked with a suction pump, and supplied to the developing device. a developing agent agitating mechanism for reducing the unevenness of the toner density of the replenishment developer stored in the replenishment developer accommodating container, the carrier in the replenishment developer in the conveying tube is replenished into the developing device Detecting the amount ratio, and the mass ratio, compared with the mass ratio of the carrier in the replenishment developer accommodated in the replenishment developer accommodating container, when there is a difference in their mass ratio, the developer An electrophotographic developer replenishing method characterized in that an operation of a stirring mechanism is controlled to reduce a deviation in toner concentration of a replenishing developer accommodated in the replenishing developer accommodating container .
2. 2. The electrophotographic developer replenishing method according to 1 above, wherein a magnetic permeability sensor is used for detecting the mass ratio of the carrier in the replenishing developer replenished to the developing device .

3. An electrophotographic developing apparatus using the electrophotographic developer supply method described in 1 or 2 above.
4). 4. An electrophotographic developing method using the electrophotographic developing apparatus according to 3 above.
5. 5. The electrophotographic developing method according to 4 above, wherein the mass ratio of the carrier in the replenishment developer accommodated in the replenishment developer container is 3% by mass or more and less than 30% by mass.
6). 6. The electrophotographic developing method according to 4 or 5 above, wherein the mass ratio of the carrier in the developer accommodated in the developing device is 85% by mass or more and less than 98% by mass.
7). A process cartridge comprising at least a photosensitive member and a developing unit, wherein an image is formed using the electrophotographic developing method according to any one of 4 to 6.

  According to the present invention, the toner concentration of the developer in the developing device in the trickle developing method can be controlled with high accuracy.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present invention. FIG. 2 is a diagram illustrating a schematic configuration illustrating a structure around a developing unit of a developing device according to an embodiment of the present invention. It is a schematic block diagram of the developer supply part used by this invention. (A) is an external view which shows schematic structure of the nozzle provided in a developer supply apparatus, (b) is the axial sectional drawing, (c) is the code | symbol AA in (b). It is sectional drawing. It is sectional drawing which shows schematic structure of a screw pump. FIG. 6 is a perspective view of a state where a developer containing member is filled with a developer. FIG. 6 is a front view showing a state where the developer inside the developer containing member is discharged and reduced in volume. It is explanatory drawing which shows the coating layer of the carrier for electrophotography of this invention. It is a perspective view of the resistance measurement cell used for the measurement of the resistivity of a carrier.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated based on drawing. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of an embodiment of the present invention, and does not limit the scope of the claims.

The present invention relates to electrophotographic development employing a trickle development method. The amount of developer replenished to the developing device is determined based on the amount of toner used in the developing device, but the control is based on the developer replenishment speed determined by the developer transport amount with respect to time and the developer supply time. Done. At this time, if the toner concentration of the replenished developer is not constant, a deviation from the target amount in the toner amount / carrier amount replenished in the developing device occurs.
The cause of fluctuations in the toner concentration of the developer to be replenished includes unevenness in the toner concentration of the developer for replenishment in the developer container, and the developer in the portion where the toner concentration is high / low due to the bias. Is supplied, the developer in the developing device becomes higher / lower than the target toner concentration.
When the toner concentration of the developer in the developing device is higher than the target, the toner charge amount is lower than the target, and there is a concern about toner scattering and background contamination. In addition, when the toner concentration of the developer in the developing device is lower than the target, the charge amount of the toner becomes higher than the target, and there is a concern that the image density is lowered.

In the future, it is considered that higher precision is required for the control of the electrophotographic developing apparatus. Therefore, when high-precision toner density control is required, it is necessary that the toner density of the replenishment developer is always constant.
In the present invention, the toner concentration of the developer supplied to the developing device is monitored. When the toner concentration detected by the monitoring is different from the toner concentration of the whole developer contained in the developer container, the toner density of the developer in the developer container is biased. In this case, the toner density deviation detection result is fed back to operate a mechanism for solving the deviation of the toner density of the developer in the developer container, and the toner density of the developer in the developer container is made uniform. As a result of the uniformization, the toner concentration of the developer supplied to the developing device becomes equal to the toner concentration of the entire developer stored in the developer container, and is supplied only by the developer supply speed and the developer supply time. It is possible to determine the toner amount with high accuracy.

A magnetic permeability sensor is preferably used for monitoring the concentration of toner to be replenished. By using the magnetic permeability sensor, the mass ratio of the carrier in the developer can be detected with high accuracy in real time and in a space-saving manner, so that the toner concentration can be detected with high accuracy.
The monitoring timing may be continuously performed or may be an operation only when the developer is replenished. Further, although a certain time / replenishment frequency interval may be provided, if the interval is too long, the control accuracy is lowered. Therefore, it is preferable to set according to the level of accuracy required for the developing device.
It is preferable to use a stirrer for the mechanism for resolving the uneven toner concentration of the developer in the developer container. By using the stirrer, the developer in the developer container can be moved reliably and quickly, and the unevenness of the toner density can be solved. The stirring mechanism may be either a mechanism that stirs by stirring with a rod-shaped / plate-shaped mudler, or a mechanism that rotates and stirs a blade-shaped mudler. The blades may be propeller-like to promote developer convection.

Even if a mechanism other than the stirring device is used, there is no problem as long as the unevenness of the toner concentration of the developer in the developer container can be solved. Other than the stirring device, as a method for making the toner concentration in the developer container uniform, there are a method of convection of the developer using air, a method of shaking the developer container itself, and a shape of the developer container. There is a method of deforming.
When the replenishment developer is filled in a storage container whose shape is easily deformed, and the replenishment developer is sucked with a suction pump and supplied to the developing device, the toner concentration in the replenishment developer container is uniform. This is preferable because it can be further promoted and can be transported to the developing device without applying excessive stress to the developer. Further, since it is not necessary to add a member such as a conveyance screw to the conveyance path, conveyance by the suction pump does not become an obstacle when the toner concentration of the developer supplied to the developing device is detected by a magnetic permeability sensor or the like. Therefore, it is preferable.

In the present invention, the mass ratio of the carrier in the developer contained in the developing device 10 (see FIG. 2) is preferably 85% by mass or more and less than 98% by mass. If it is less than 85% by mass, toner scattering from the developing device tends to occur, which causes a defective image. If it is 98% by mass or more, the charge amount of the toner excessively increases or the supply amount of the toner is insufficient, so that the image density is lowered and a defective image is caused.
The replenishment developer accommodated in the developer container 230 (see FIG. 2) preferably has a carrier mass ratio of 3% by mass or more and less than 30% by mass.
When the mass ratio of the carrier in the replenishment developer accommodated in the developer container 230 is less than 3% by mass, the amount of the replenished carrier is very small, so that the replenishment effect is sufficiently obtained. I can't. On the other hand, if it exceeds 30% by mass, stable supply of the replenishment developer to the developer accommodating portion cannot be obtained.

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.
In the image forming apparatus main body 100, the image forming apparatus 2A, 2B, 2C, and 2D, which are process cartridges having the photosensitive members 1 (1a, 1b, 1c, and 1d) that are four image carriers, are provided. Removably attached to each. A transfer device in which the transfer belt 8 is mounted between a plurality of rollers so as to be rotatable in the direction of arrow A is disposed in the approximate center of the image forming apparatus 100.
The photoreceptor 1 provided in each of the image forming units 2A, 2B, 2C, and 2D is disposed so as to contact the lower surface of the transfer belt 8. In correspondence with the image forming units 2A, 2B, 2C, and 2D, developing devices 10A, 10B, 10C, and 10D having different toner colors are arranged.

The image forming units 2A, 2B, 2C, and 2D are units having the same configuration, the image forming unit 2A forms an image corresponding to magenta, and the image forming unit 2B forms an image corresponding to cyan. The image forming unit 2C forms an image corresponding to the yellow color, and the image forming unit 2D forms an image corresponding to the black color.
In each of the developing devices 10A, 10B, 10C, and 10D disposed in the image forming units 2A, 2B, 2C, and 2D, a two-component developer including toner and a carrier is used, and a developer replenishing device 200 described later is used. (See FIG. 3), toner is replenished in accordance with the output of a toner density sensor (not shown) provided in the developer container 14, and the carrier is also replenished to discharge the old developer and replace the developer. The development method that can be used is adopted.
A developer replenishing device 200 (200A, 200B, 200C, 200D) is disposed above the image forming units 2A, 2B, 2C, 2D. The developer supply device 200 has a configuration for supplying new toner and a new carrier different from the toner to be supplied to the photosensitive drum 1 to the development device 10, and the configuration is shown in FIG. Has been.

An exposure device 6 as a writing unit is disposed below the image forming units 2A, 2B, 2C, and 2D.
The exposure device 6 is arranged in four laser diode (LD) light sources prepared for each color, a set of polygon scanners composed of six polygon mirrors and a polygon motor, and the route of each light source. It is composed of a lens such as an fθ lens or a long cylindrical lens, or a mirror. Laser light emitted from the laser diode is deflected and scanned by a polygon scanner and is irradiated onto the photosensitive member 1.
Between the transfer belt 8 and the developer supply device 200, there is provided a fixing device 9 for fixing the image on the transfer paper onto which the image has been transferred. A discharge path 51 is formed on the downstream side of the fixing device 9 in the conveyance direction of the transfer sheet, and the transfer sheet conveyed there can be discharged onto a discharge tray 53 by a discharge roller pair 52.
A paper feed cassette 7 that can store transfer paper is disposed below the image forming apparatus 100.

  Next, the operation of the image forming apparatus 100 in image formation will be described. When the image forming operation is started, each photoconductor 1 rotates in the clockwise direction in FIG. Then, the surface of each photoconductor 1 is uniformly charged by the charging roller 301 of the charging unit 3. Then, laser light corresponding to a magenta image by the exposure device 6 is applied to the photoreceptor 1a of the image forming unit 2A, and laser light corresponding to a cyan image is applied to the photoreceptor 1b of the image forming unit 2B. The 2C photoconductor 1c is irradiated with a laser beam corresponding to a yellow image, and the photoconductor 1d of the image forming unit 2D is irradiated with a laser beam corresponding to a black image, and a latent image corresponding to image data of each color. Are formed respectively. Each latent image reaches the position of the developing devices 10A, 10B, 10C, and 10D by the rotation of the photosensitive member 1, and is developed there by toners of magenta, cyan, yellow, and black. Become.

  On the other hand, the transfer paper is fed from the paper feed cassette 7 by the separation paper feed unit, and the toner image formed on each photoconductor 1 by the registration roller pair 55 provided immediately before the transfer belt 8. It is conveyed at the same timing. The transfer paper is charged to a positive polarity by a paper suction roller 54 disposed near the entrance of the transfer belt 8, and thereby electrostatically attracted to the surface of the transfer belt 8. The transfer paper is conveyed while being adsorbed to the transfer belt 8, and magenta, cyan, yellow, and black toner images are sequentially transferred to form a four-color superimposed full-color toner image. . The transfer paper is heated and pressed by the fixing device 9 to melt and fix the toner image, and then passes through a paper discharge system and is discharged onto a paper discharge tray 53 at the top of the image forming apparatus 1.

Next, the configuration around the developing device will be described. FIG. 2 is a schematic cross-sectional view showing a developing device provided in the image forming apparatus of the present invention and the structure around it. In FIG. 2, a developer replenishing device 200 (see FIG. 3) for replenishing a developer composed of a new toner and carrier is provided in the developing device 10 above the developing device 10, and below the developing device 10. Is provided with a developer discharging device 300 for discharging the developer that has become excessive in the developing device 10.
The developing device 10 includes a housing 15 (see FIG. 3) having a developer accommodating portion 14 for accommodating a two-component developer composed of toner and a carrier, and a photoreceptor 1 as an image carrier on the opening side of the housing 15. The developer roll 12 as a developer carrying member disposed so as to rotate in a state close to the developer, and two transports as developer agitating and conveying members disposed so as to rotate within the developer container 14. The screws 11a and 11b and the layer thickness regulating member 13 disposed in pressure contact with or close to the surface of the developing roller 12 constitute the main part.

Among these, the developing roller 12 is a cylindrical sleeve 121 that rotates and includes a magnet roll 120 fixed inside. Further, the developer accommodating portion 14 is divided into two by a central partition 14c, and is composed of accommodating spaces 14a and 14b that are communicated by communicating portions on both ends, and a conveying screw 11a that rotates in the accommodating spaces 14a and 14b. The developer is circulated and conveyed between the storage spaces 14a and 14b while being agitated by 11b. The layer thickness regulating member 13 has a double structure of a nonmagnetic member and a magnetic member, and is arranged so that the tip thereof faces a predetermined magnetic pole of the magnet roll 120.
The developer supply device 200 includes a developer container 230 that stores a two-component developer for supply, and a developer replenisher that sends the two-component developer in the developer container 230 to the developer storage unit 14 for supply. 220. The developer replenisher 220 is provided between the developer container 230 and the developing device 10 so as to be connected to each other.
The conveyance tube 221 is provided with a magnetic permeability sensor 270 to detect the toner concentration of the replenishment developer supplied to the developing device 10. The developer container 230 is provided with a replenishment developer stirring device 271 and is controlled so as to operate according to the toner concentration detected by the magnetic permeability sensor 270.
The detailed configuration of the developer supply device 200 will be described later with reference to FIG.

The developer discharge device 300 collects the two-component developer that is excessive in the developer container 4 and collects the developer that overflows and overflows from the developer container 14 to the collection container 330. It comprises a discharge pipe 331 as developer discharge means. The discharge pipe 331 is disposed such that the upper opening 331a is positioned at a predetermined height in the developer accommodating portion 14, and discharges the developer over the upper opening 331a at the predetermined height. It has become.
The developer discharge device according to the present invention is not limited to the above-described configuration. For example, a developer discharge port is opened at a predetermined location of the housing 15 and the developer discharge port is replaced with the discharge pipe 331. A conveying member such as a discharging screw as a developer discharging means may be installed in the vicinity of the toner container so that the developer discharged from the developer discharging port is conveyed to the collection container 330.
Moreover, it is also possible to provide this discharge screw at the end or inside of the discharge pipe 331 of this embodiment.

Next, the developing operation of the developing device will be described with reference to FIG.
First, the developer in the developing device previously stored in the developer container 14 is stirred and sufficiently mixed by the conveying screws 11a and 11b and is frictionally charged, and then supplied to the developing roller 12. It adheres to the surface of the sleeve 121 in layers.
The layered developer adhering to the developing roller 12 is regulated to a predetermined thickness by the layer thickness regulating member 13 to be a uniform layer, and then the developing area that faces the photoreceptor 1 as the sleeve 121 rotates. It is conveyed to D. In this development area D, the toner of the two-component developer is electrostatically adsorbed to the latent image formed on the photoreceptor 1 in accordance with the image of the original on the image forming apparatus main body 100 (see FIG. 1). Development is performed, and a toner image is formed on the photoreceptor 1.
The toner image formed on the photoreceptor 1 is transferred onto the transfer paper on the image forming apparatus main body 100 side, and is fixed onto the transfer paper by the fixing unit.

By repeating this developing operation, the toner contained in the developer in the developing device in the developer accommodating portion 14 is consumed and gradually decreases. When this toner reduction is detected by the above-described toner density sensor. Then, the developer supply device 220 of the developer supply device 200 is driven. As a result, a replenishment developer containing a carrier and toner, which will be described in detail below, housed in the developer housing member 231 of the developer housing 230 is replenished. The new two-component developer replenished in the developer accommodating portion 14 is stirred by the conveying screws 11a and 11b in the developer accommodating portion 14 and sufficiently mixed with the developer in the developing device accommodated before replenishment. Is done.
In the developer accommodating portion 14, the supply of the developer for replenishment from the developer replenishing device 200 causes the carrier and the toner to be replenished at a predetermined ratio, so that the amount of developer in the developer accommodating portion 14 gradually increases. It becomes. The two-component developer that becomes excessive in the developer accommodating portion 14 overflows beyond the regulated height of the accommodating portion 14 and is accommodated in the collection container 330 through the discharge pipe 331 of the developer discharging device 300.
The replenishment developer of the present invention is a material containing at least a toner and a carrier. As the toner / carrier for the replenishment developer accommodated in the developer accommodating unit 230, those described below can be used.
Further, as the toner of the developer in the developing device, the same toner as that stored in the developer container 230 or a different toner can be used, and the carrier is also stored in the developer container 230. It can be used with the same carrier or different carriers.

In the image forming apparatus 100 of this embodiment, a developer storage member 231 whose shape is easily deformed is filled with a replenishment developer, and the replenishment developer is sucked by the screw pump 223 and supplied to the development device 10. A developer supply device 200 is provided.
Hereinafter, the configuration of the developer supply device 200 will be described in detail with reference to FIGS.
FIG. 3 is a schematic configuration diagram of a developer supply device 200 used in the present invention. Inside the developer container 230 provided in the developer supply device 200, a developer storage member 231 as a bag-shaped member capable of volume reduction is provided. A new replenishment developer to be replenished to the developer accommodating portion 14 of the developing device 10 is accommodated in the developer accommodating member 231. The developer accommodating member 231 is reduced in volume as the internal pressure decreases due to the developer being supplied to the developer accommodating portion 14.

The developer replenisher 220 includes a screw pump 223 that is connected to the upper end of a replenishing port 15 a provided at a predetermined location of the housing 15, a nozzle 240 that is connected to the screw pump 223, and a nozzle 240. And an air supply means 260 that is connected and is driven in accordance with a detection signal from a toner concentration sensor (not shown) or the like installed in the developer storage unit 14 to supply an appropriate amount of developer. The developer is supplied from the developer container 230 to the developer container 14.
Between the screw pump 223 and the nozzle 240, there is a transport tube 221 as a developer transport passage communicating with the screw pump 223. The transport tube 221 is preferably made of a rubber material such as polyurethane, nitrile, and EPDM that is flexible and excellent in toner resistance.
The conveyance tube 221 is provided with a magnetic permeability sensor 270 to detect the toner concentration of the replenishment developer supplied to the developing device 10. The developer container 230 is provided with a replenishment developer stirring device 271, and is controlled to operate according to the toner concentration detected by the magnetic permeability sensor 270.
The developer supply device 200 has a container holder 222 for supporting a developer container 230 as a developer container, and the container holder 222 is made of a material having high rigidity such as resin.

The developer container 230 includes a developer storage member 231 as a bag-like member formed of a flexible sheet material, and a base portion 232 as a discharge port forming member that forms a developer discharge port. There is no restriction | limiting in particular as a material of the developer accommodating member 231, A thing with good dimensional accuracy is used suitably. For example, a resin such as a polyester resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyvinyl chloride resin, a polyacrylic acid, a polycarbonate resin, an ABS resin, or a polyacetal resin is preferably exemplified.
Further, the base part 232 is provided with a sealing material 233 formed of sponge, rubber or the like, and the sealing material 233 is provided with a cross-shaped cut. Then, by passing the nozzle 240 of the developer replenisher 220 through this notch, the developer container 230 and the developer replenisher 220 are connected and fixed.

In the present embodiment, the base portion 232 is provided below the developer container 230. Here, the state where the base part 232 is provided below means that the base part 232 faces downward in the developer container 230 in a state where the developer container 230 is disposed in the developer supply device 200. It shows that it is provided at a position including a vertical component.
The position at which the base 232 is provided in the developer container body is not limited to this, and the developer container in a state where the developer container 230 is disposed in the developer supply device 200. 230 may be provided in the horizontal direction of the main body, or may be provided in an oblique direction.
The developer container is sequentially replaced with a new one as the toner is consumed. However, the developer container 230 according to this embodiment can be easily attached and detached by having the above-described configuration. In addition, it is possible to prevent toner leakage at the time of replacement or use.

  4A is an external view showing a schematic configuration of a nozzle 240 provided in the developer replenisher 220, FIG. 4B is an axial sectional view, and FIG. FIG. 4B is a cross-sectional view taken along line AA in FIG. As shown in FIG. 4B, the nozzle 240 has a double tube structure including an inner tube 241 and an outer tube 242 that accommodates the inner tube 241 therein. The inside of the inner tube 241 serves as a developer flow path 241a as a developer transport path for discharging the developer in the developer container 230. The toner in the developer container 230 is sucked by the suction force of the screw pump 223 and is drawn into the screw pump 223 through the developer flow path 241a.

  FIG. 5 is a cross-sectional view showing a schematic configuration of the screw pump 223. The screw pump 223 is called a uniaxial eccentric screw pump and includes a rotor 224 and a stator 225 therein. The rotor 224 has a shape in which a circular cross section is twisted in a spiral shape, is formed of a hard material, and is fitted inside the stator 225. On the other hand, the stator 225 is formed of a rubber-like flexible material, and has a hole whose elliptical cross section is spirally twisted, and the rotor 224 is fitted into this hole. Further, the helical pitch of the stator 225 is formed to be twice as long as the helical pitch of the rotor 224. The rotor 224 is connected to a drive motor 226 for rotating the rotor 224 via a universal joint 227 and a bearing 228.

In this configuration, the toner and carrier conveyed from the developer container 230 through the developer flow path 241 a of the nozzle 240 and the conveyance tube 221 are detected by the magnetic permeability sensor 270 while the toner concentration is detected by the screw pump 223. The toner enters from the toner suction port 223a. Then, it enters the space formed between the rotor 224 and the stator 225 and is sucked and conveyed in the right direction in FIG. 5 as the rotor 224 rotates. The toner that has passed through the space between the rotor 224 and the stator 225 falls downward from the toner dropping port 223 b and is supplied into the developing device 10 through the developer supply port 14 of the developing device 10.
The developer replenisher 220 used in this embodiment includes an air supply unit 260 that supplies air into the developer container 230.

As shown in FIG. 3, the air flow paths 244a and 244b are respectively connected to air pumps 260a and 260b as separate gas delivery devices via air supply paths 261a and 261b as gas supply paths.
As shown in FIG. 4B, the air flow path 244 is provided as an air supply passage between the inner tube 241 and the outer tube 242 of the nozzle 240 of the developer replenisher 220. As shown in FIG. 4C, the air flow path 44 is composed of two flow paths 244a and 244b having a semicircular cross section independent from each other.

As the air pumps 260a and 260b, a normal diaphragm type air pump can be used. The air sent out from these air pumps 260a and 260b is supplied into the toner container 230 from air supply ports 246a and 246b as gas supply ports of the respective air channels through the air channels 244a and 244b, respectively. Each air supply port 246a, 246b is located below the toner outlet 247 as a developer outlet of the toner channel 241a in the figure. As a result, the air supplied from the air supply ports 246a and 246b is supplied to the toner in the vicinity of the toner outlet 247, and is left unused for a long period of time and the toner outlet 247 is clogged. Even in such a state, the toner blocking the toner outlet 247 can be destroyed.
The air supply passages 261a and 261b are provided with on-off valves 262a and 262b as closing means that are opened and closed by a control signal from a control unit as gas delivery control means (not shown). The on-off valves 262a and 262b operate to open the valve when the ON signal is received from the control unit and allow air to pass therethrough, and when the OFF signal is received from the control unit to close the valve and prevent the passage of air.

Next, the operation of the developer supply device 220 in this embodiment will be described with reference to FIG.
The control unit receives the signal indicating that the toner density is insufficient from the developing device 10 and starts the developer supply operation. In this developer replenishment operation, first, the air pumps 260a and 260b are driven to supply air into the developer container 230, and the drive motor 226 of the screw pump 223 is driven to suck and convey the developer. .
When air is sent out from the air pumps 260a and 260b, the air enters the air flow paths 244a and 244b of the nozzle 240 from the air supply paths 261a and 261b, and is supplied into the developer container 230 from the air supply ports 246a and 246b. The By this air, the developer in the developer container 230 is agitated and becomes a state in which a large amount of air is contained, and fluidization is promoted.

Further, when air is supplied into the developer container 230, the internal pressure in the developer container 230 increases. Therefore, a pressure difference is generated between the internal pressure and the external pressure (atmospheric pressure) of the developer container 230, and a force that moves in the direction in which the pressure is applied acts on the fluidized developer. As a result, the developer in the developer container 230 flows out from the direction in which pressure is applied, that is, from the developer outlet 247.
In the present embodiment, the suction force by the screw pump 223 also acts, and the developer in the developer container 230 flows out from the developer outlet 247.

As described above, the developer that has flowed out of the developer container 230 moves from the developer outlet 247 through the developer channel 241 a of the nozzle 240 into the screw pump 223 via the transport tube 221.
When the toner concentration is detected by the magnetic permeability sensor 270 while moving in the transport tube and is different from the total toner concentration stored in the developer storage container, the replenishment developer stirring device 271 is used. The toner concentration of the developer in the developer container is made uniform.
After moving through the screw pump 223, the replenishment developer falls downward from the developer drop port 223b, and the developer is replenished into the developing device 10 from the developer supply port 14. When a certain amount of developer supply is completed, the control unit stops driving the air pumps 260a and 260b and the drive motor 226, closes the on-off valves 262a and 262b, and ends the toner supply operation. Thus, by closing the on-off valves 262a and 262b at the end of the toner supply operation, the toner in the toner container 230 is prevented from flowing back to the air pumps 260a and 260b through the air supply passages 244a and 244b of the nozzle 240. doing.

The supply amount of air supplied from the air pumps 260 a and 260 b is set to be smaller than the suction amount of toner and air by the screw pump 223. Therefore, as the toner is consumed, the internal pressure of the developer container 230 decreases. Here, since the developer accommodating member 231 of the developer accommodating unit 230 in this embodiment is formed of a flexible sheet material, the volume is reduced as the internal pressure decreases.
FIG. 6 is a perspective view of the developer containing member 231 filled with the developer.
FIG. 7 is a front view showing a state in which the developer inside the developer containing member 231 is discharged and reduced in volume (squeezed). Here, it is desirable that the developer containing member 231 has a volume reduced by 60% or more.

The toner used in the present invention includes at least a binder resin and a colorant, and further includes a release agent, a charge control agent, and other components as necessary.
The toner production method will be described below, but the toner production method is not particularly limited to one, and can be appropriately selected according to the purpose. Examples thereof include a pulverization method, a suspension polymerization method, an emulsion polymerization method, and a polymer suspension method in which an oil phase is emulsified, suspended or aggregated in an aqueous medium to form toner base particles.

  The binder resin for the toner used in the present invention is not particularly limited, and can be appropriately selected from known ones according to the purpose. For example, styrene such as polystyrene, poly-p-styrene, polyvinyltoluene, and the like Substituted homopolymer, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, Styrene-methacrylic acid copolymer unit, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer Polymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer Styrene copolymers such as styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isopropyl copolymer, styrene-maleic acid ester copolymer, polythyme methacrylate resin, polybutyl methacrylate resin , Polyvinyl chloride resin, polyvinyl acetate resin, polyethylene resin, polyester resin, polyurethane resin, epoxy resin, polyvinyl butyral resin, polyacrylic acid resin, rosin resin, modified rosin resin, terpene resin, phenol resin, aliphatic or aromatic Hydrocarbon resins and aromatic petroleum resins can be used alone or in combination.

The colorant is not particularly limited and may be appropriately selected from known dyes and pigments according to the purpose. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G , G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR ), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Lead Red, Lead Red, Cadmium Red, Cadmium Mummer Curry Red, Antimony Zhu, Permanent Red 4R, Parare , Phi Sae Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Risor Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzidine orange, perinone orange, oil orange, cobalt blue, cerulean blue, alkaline blue rake, peacock blue rake, Victoria blue rake, metal-free phthalocyanine blue, phthalocyanine blue , Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine Blue, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome oxide, pyridian, emerald green, pigment green B, naphthol green B, green gold, acid Examples include lean lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, and lithobon. These may be used individually by 1 type and may use 2 or more types together.
The content of the colorant in the toner is preferably 1 to 15% by mass, and more preferably 3 to 10% by mass.

  The colorant may be used as a master batch combined with a resin. The resin is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, styrene or a substituted polymer thereof, styrene copolymer, polymethyl methacrylate resin, polybutyl Methacrylate resin, polyvinyl chloride resin, polyvinyl acetate resin, polyethylene resin, polypropylene resin, polyester resin, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic hydrocarbon resin, alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin and the like. These may be used individually by 1 type and may use 2 or more types together.

There is no restriction | limiting in particular as a mold release agent, According to the objective, it can select suitably from well-known things, For example, waxes etc. are mentioned suitably.
Examples of waxes include carbonyl group-containing waxes, polyolefin waxes, long chain hydrocarbons, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, a carbonyl group-containing wax is preferable.
Examples of the carbonyl group-containing wax include polyalkanoic acid esters, polyalkanol esters, polyalkanoic acid amides, polyalkylamides, dialkyl ketones, and the like. Examples of the polyalkanoic acid ester include carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecane. Examples thereof include diol distearate. Examples of polyalkanol esters include tristearyl trimellitic acid and distearyl maleate. Examples of the polyalkanoic acid amide include dibehenyl amide. Examples of the polyalkylamide include trimellitic acid tristearylamide. Examples of the dialkyl ketone include distearyl ketone. Of these carbonyl group-containing waxes, polyalkanoic acid esters are particularly preferred.
Examples of the polyolefin wax include polyethylene wax and polypropylene wax.
Examples of the long chain hydrocarbon include paraffin wax and sazol wax.

There is no restriction | limiting in particular as melting | fusing point of a mold release agent, Although it can select suitably according to the objective, 40-160 degreeC is preferable, 50-120 degreeC is more preferable, 60-90 degreeC is especially preferable.
When the melting point is less than 40 ° C., the wax may adversely affect the heat resistant storage stability, and when it exceeds 160 ° C., a cold offset may easily occur during fixing at a low temperature.
The melt viscosity of the release agent is preferably 0.005 to 1 Pa · s (5 to 1,000 cps) as a measured value at a temperature 20 ° C. higher than the melting point of the wax, and 0.01 to 0.1 Pa · s. (10-100 cps) is more preferable. If the melt viscosity is less than 0.005 Pa · s, the releasability may be lowered, and if it exceeds 1 Pa · s, the effect of improving hot offset resistance and low-temperature fixability may not be obtained. .
There is no restriction | limiting in particular as content in the said toner of a mold release agent, Although it can select suitably according to the objective, 1-40 mass% is preferable and 3-30 mass% is more preferable. When the content exceeds 40% by mass, the fluidity of the toner may be deteriorated.

The charge control agent is not particularly limited, and a positive or negative charge control agent can be appropriately selected and used depending on whether the charge charged on the photoconductor is positive or negative.
As the negative charge control agent, for example, a resin or compound having an electron donating functional group, an azo dye, a metal complex of an organic acid, or the like can be used. Specifically, Bontron (product numbers: S-31, S-32, S-34, S-36, S-37, S-39, S-40, S-44, E-81, E-82, E -84, E-86, E-88, A, 1-A, 2-A, 3-A) (above, manufactured by Orient Chemical Industry Co., Ltd.)), Kaya Charge (part numbers: N-1, N-2), Kaya Set Black (Part No .: T-2, 004) (Nippon Kayaku Co., Ltd.), Eisenspiron Black (T-37, T-77, T-95, TRH, TNS-2) FCA-1001-N, FCA-1001-NB, FCA-1001-NZ (manufactured by Fujikura Kasei Co., Ltd.), and the like.

As the positive charge control agent, for example, basic compounds such as nigrosine dyes, cationic compounds such as quaternary ammonium salts, metal salts of higher fatty acids, and the like can be used. Specifically, Bontron (part numbers: N-01, N-02, N-03, N-04, N-05, N-07, N-09, N-10, N-11, N-13, P -51, P-52, AFP-B) (above, manufactured by Orient Chemical Co., Ltd.), TP-302, TP-415, TP-4040 (above, manufactured by Hodogaya Chemical Co., Ltd.), Copy Blue PR, Copy Charge ( Product number: PX-VP-435, NX-VP-434) (manufactured by Hoechst), FCA (product number: 201, 201-B-1, 201-B-2, 201-B-3, 201-PB, 201-PZ, 301) (manufactured by Fujikura Kasei Co., Ltd.), PLZ (product numbers: 1001, 2001, 6001, 7001) (manufactured by Shikoku Kasei Kogyo Co., Ltd.), and the like.
These may be used individually by 1 type and may use 2 or more types together.
The addition amount of the charge control agent is determined by the toner production method including the kind of the binder resin and the dispersion method, and is not uniquely limited. 1-10 mass parts is preferable and 0.2-5 mass parts is more preferable. When the addition amount exceeds 10 parts by mass, the chargeability of the toner is too large, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is reduced, and the image density is increased. If the amount is less than 0.1 parts by mass, the charge rise and charge amount are insufficient, and the toner image may be easily affected.

In addition to binder resin, release agent, colorant, and charge control agent, inorganic fine particles, fluidity improver, cleaning improver, magnetic material, metal soap, etc. are added to the toner material as necessary. can do.
As inorganic fine particles, for example, silica, titania, alumina, cerium oxide, strontium titanate, calcium carbonate, magnesium carbonate, calcium phosphate, etc. can be used, and silica fine particles hydrophobized with silicone oil, hexamethyldisilazane, etc. It is more preferable to use titanium oxide that has been subjected to a specific surface treatment.

Examples of the silica fine particles include, for example, Aerosil (product numbers: 130, 200 V, 200 CF, 300, 300 CF, 380, OX50, TT600, MOX80, MOX170, COK84, RX200, RY200, R972, R974, R976, R805, R811, R812, T805, R202, VT222, RX170, RXC, RA200, RA200H, RA200HS, RM50, RY200, REA200 (above, manufactured by Nippon Aerosil Co., Ltd.), HDK (part number: H20, H2000, H3004, H2000 / 4, H2050EP, H2015EP, H3050EP) , KHD50), HVK2150 (above, manufactured by Wacker Chemical Co., Ltd.), Cabozil (Part No .: L-90, LM-130, LM-150, M-5, PTG, MS-55, -5, HS-5, EH-5, LM-150D, M-7D, MS-75D, TS-720, TS-610, TS-530) (or, can be used Cabot Corp.).
The addition amount of the inorganic fine particles is preferably 0.1 to 5.0 parts by mass, more preferably 0.5 to 3.2 parts by mass with respect to 100 parts by mass of the toner base particles.

The method for producing the toner in the present invention is not particularly limited as described above, but examples of the method for producing the pulverization method include the following.
The toner materials are mixed, and the mixture is charged into a melt kneader and melt kneaded. As the melt kneader, for example, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type extruder manufactured by Toshiba Machine Co., Ltd., twin screw extruder manufactured by Casey Kay Co., Ltd. Preferably used. This melt-kneading is preferably performed under appropriate conditions so as not to cause the molecular chains of the binder resin to be broken. Specifically, the melt kneading temperature is performed with reference to the softening point of the binder resin. If the temperature is higher than the softening point, cutting is severe, and if the temperature is too low, dispersion may not proceed.

In the pulverization method, the kneaded product obtained by the kneading is pulverized. In this pulverization, it is preferable that the kneaded material is first coarsely pulverized and then finely pulverized. In this case, a method of pulverizing by colliding with a collision plate in a jet stream, pulverizing particles by colliding with each other in a jet stream, or pulverizing with a narrow gap between a mechanically rotating rotor and a stator is preferably used.
In the classification, the pulverized product obtained by the pulverization is classified and adjusted to particles having a predetermined particle diameter. The classification can be performed, for example, by removing the fine particle portion by a cyclone, a decanter, centrifugation, or the like.
After the pulverization and classification are completed, the pulverized product is classified into an air stream by centrifugal force or the like to produce a toner having a predetermined particle size.

  Further, in order to improve the fluidity, storage stability, developability and transferability of the toner, inorganic fine particles such as hydrophobic silica fine powder may be further added to and mixed with the toner base particles produced as described above. For mixing the additives, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. In order to change the load history applied to the additive, the additive may be added midway or gradually. In this case, you may change the rotation speed, rolling speed, time, temperature, etc. of a mixer. Alternatively, a strong load may be applied first, then a relatively weak load, or vice versa. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, and a Henschel mixer. Next, the toner can be obtained by passing through a sieve for the purpose of removing coarse particles and aggregated particles.

The carrier will be described below, but this is an example showing the embodiment of the present invention, and the present invention is not limited to this.
FIG. 8 is an explanatory view showing a coating layer of a carrier. As shown in FIG. 8, the carrier particles used in the present invention include a core material 26 and a coating layer 27 that covers the core material 26. The coating layer 27 includes at least a binder resin, Hard particles (hereinafter referred to as first particles G1) are included.
As a layer covering the core material 26, it is possible to have other layers in addition to the covering layer 27. Furthermore, the coating layer 27 can contain other components as needed in addition to the binder resin, the first particles G1, and the second particles G2.
The average thickness h of the resin portion in the coating layer 27 represents the thickness of the film that exists in the direction perpendicular to the surface of the core material 26. In the thickness from the surface of the core material 26 to the surface of the coating layer 27, the particle portion The average thickness of the removed resin portion is shown.

As the thickness of the resin portion in the coating layer 27, the thickness ha of the resin portion existing between the surface of the core material 26 and the particles, the thickness hb of the resin portion existing between the particles, and the resin portion existing on the particles Thickness hc and the thickness hd of the resin portion existing on the core material 26.
The average thickness h of the resin part in the coating layer 27 can be measured by observing the cross section of the carrier using, for example, a transmission electron microscope (TEM). Specifically, along the carrier surface, the thickness of the resin part in the coating layer 27 at intervals of 0.2 μm (the thickness ha of the resin part existing between the core material surface and the particles, the resin part existing between the particles) The thickness hb, the thickness hc of the resin part on the particles, and the thickness hd of the resin part on the core material) were measured using a transmission electron microscope (TEM), and 50 measurement values were obtained. Is the average thickness h of the resin portion in the coating layer 27.

As a specific calculation method, the value of the average thickness h of the resin portion in the coating layer 27 is a value obtained by summing up the respective measured values obtained by the above-described method and dividing the obtained value by the number of measured values. It is. The number of measured values is as follows: the thickness ha of the resin part existing between the surface of the core material 26 and the particles, the thickness hb of the resin part existing between the particles, the thickness hc of the resin part on the particles, and the core material 26 The thickness hd of each resin part is regarded as one and counted.
For example, at the measurement point A shown in FIG. 8, since the thickness hb and the thickness hc exist, the number of measurement values at the measurement point A is two.
In the measurement method described above, among the 50 measurement values, a plurality of measurement values (for example, the thickness ha and the thickness hc) are measured as the measurement values of the thickness of the resin portion in the coating layer 27 at the last measured location. When the total value of the measured values is divided by the value of “49+ (number of measured values at the last measured point)”, which is the number of measured values, It is set as the value of average thickness h.

The particle diameter D1 (μm) of the first particles G1 included in the coating layer 27 satisfies the relationship of 1 <(D1 / h) <10 with respect to the average thickness h (μm) of the resin portion in the coating layer 27. More preferably, the relationship 1 <(D1 / h) <5 is satisfied.
When the particle diameter D1 of the first particle G1 and the average thickness h of the resin portion in the coating layer 27 satisfy the above relational expression, the first particle G1 is more convex than the carrier coating layer 27. This convex portion can alleviate the strong impact applied to the binder resin of the carrier coating layer 27 due to the frictional contact between the toner and the carrier or between the carriers when agitation is performed to frictionally charge the developer. Thereby, it can suppress that the film | membrane scraping of the binder resin of the carrier coating layer 27 which is a charging generation location generate | occur | produces.

In addition, since the convex portions exist on the particle surface, the point of contact with the outside becomes a point, so that the fluidity of the carrier particles is improved. Therefore, the developer using this carrier has high transportability, hardly causes uneven transport, and image stability is improved.
Further, when the carriers are in frictional contact with each other, the particles existing in a convex shape with respect to the surface of the coating layer 27 scrape off the spent component of the toner adhering to the surface of the carrier, thereby obtaining a cleaning effect. . Thereby, it is possible to effectively prevent the phenomenon of toner spent.
When (D1 / h) is 1 or less, the first particles may be buried in the binder resin, and the effects of the first particles G1 added to the coating layer 27 may not be sufficiently obtained. Further, when (D1 / h) is 10 or more, the contact area between the first particles (G1) and the binder resin is reduced, and sufficient binding force of the first particles (G1) to the carrier particles cannot be obtained. The first particles G1 may be easily detached from the carrier particle surfaces.

The coating layer 27 preferably contains second hard fine particles (hereinafter referred to as second particles G2) in order to give the coating layer an appropriate moderate strength on average, and the particle diameter D2 of the second particles G2. (Μm) preferably satisfies 0.001 <(D2 / h) <1 with respect to the average thickness h (μm) of the resin portion in the coating layer 27, more preferably 0.01 <(D2 / h). Those satisfying <0.5 are preferred.
By making the particle diameter D2 of the second particles G2 smaller than the average thickness h of the coating layer 27, the second particles G2 can be included while being dispersed in the coating layer 27. Therefore, the strength of the coating layer can be improved on average.
The volume resistivity value of the second particles G2 is preferably 1.0 × 10 ¹² Ω · cm or less, more preferably 1.0 × 10 ¹⁰ Ω · cm or less, and further preferably 1.0 × 10 ⁸ Ω. -It is cm or less. By setting the volume resistivity of the second particle G2 to a low resistance of 1.0 × 10 ¹² Ω · cm or less, the charge imparting ability of the coating layer 27 is controlled to an appropriate low, and finally obtained. The density of image increase can be increased.

（ただし、式（１）中、Ｈは試料の厚みを表す値であり、ｒは試料の抵抗値を表す値である。） The volume resistivity of the first particle G1 and the second particle G2 in the present invention can be measured, for example, as follows.
A sample is put in a cylindrical vinyl chloride tube having an inner diameter of 25.4 mm (1 inch), and the upper and lower sides are sandwiched between electrodes. A pressure of 15 kg / cm ² is applied to these electrodes with a press machine for 1 minute. Subsequently, measurement with an LCR meter is performed in this pressurized state to obtain resistance (r). The obtained resistivity can be calculated by the following mathematical formula (1) to determine the volume resistivity.

(In formula (1), H is a value representing the thickness of the sample, and r is a value representing the resistance value of the sample.)

When the value of (D2 / h) is 1 or more, the second particle G2 is too large with respect to the thickness of the coating layer 27, so that the effect of dispersing and improving the strength of the coating layer on average is hardly exhibited. Become. Moreover, since the particle size of the 2nd particle | grains G2 is too small with respect to the coating layer 27 thickness as (D2 / h) is 0.001 or less, an effect becomes difficult to be acquired.
The average thickness T (μm) from the surface of the core material 26 to the surface of the coating layer 27 is preferably 0.1 ≦ T ≦ 3.0, and more preferably 0.1 ≦ T ≦ 2.0.
If the average thickness T from the surface of the core material 26 to the surface of the coating layer 27 is less than 0.1 μm, the total thickness of the coating layer 27 as a film covering the carrier core material 26 is too thin. As a result, the carrier core material 26 is likely to be exposed and the carrier durability is lowered.
On the other hand, if the average thickness T from the core material 26 to the surface of the coating layer 27 exceeds 3.0 μm, the film thickness formed on the surface of the core material 26 is too thick, so that the magnetization of the carrier tends to decrease and carrier adhesion occurs. There are things to do.

The average thickness h (μm) of the resin portion in the coating layer 27 is preferably 0.04 to 2 μm, and more preferably 0.04 to 1 μm.
The volume average particle diameter D1 of the first particles G1 is preferably 0.05 to 3 μm, and more preferably 0.05 to 1 μm.
The particle diameter D2 of the second particles G2 is preferably 0.005 to 1 μm, and more preferably 0.01 to 0.2 μm.
As shown in FIG. 8, the thickness T from the surface of the core material 26 to the surface of the coating layer 27 represents a thickness different from the average thickness h of the resin portion in the coating layer 27 described above. The thickness from the surface of the core material 26 to the surface of the coating layer 27 is shown.

As shown in FIG. 8, when the particle diameter D1 of the particles added in the coating layer 27 is larger than the thickness of the resin portion in the coating layer 27, the particle diameter of the particles is covered from the surface of the core material 26. The value corresponds to the thickness T up to the surface of the layer 27.
The average thickness T from the surface of the core material 26 to the surface of the coating layer 27 is obtained by, for example, observing the cross section of the carrier using a transmission electron microscope (TEM) and calculating the thickness from the surface of the core material 26 to the surface of the coating layer 27. 0.2 μm zinc particles and the like can be cited along with the alumina particles. Among these, the alumina particles have good compatibility with the binder resin used for the carrier coating material, and are excellent only in terms of dispersibility and adhesiveness. In particular, the hardness is very high, and therefore, it is particularly preferable because it is less likely to be worn and cracked against stress in the developing device 10 and can exhibit the protective effect of the coating layer and the effect of scraping the spent material over a long period of time.
As the alumina particles, alumina particles having a particle size of 5 μm or less are preferable, and those having no surface treatment, those having a surface treatment such as a hydrophobization treatment, and the like can be used.
As silica, those used for toner and those other than that can be used, and those not subjected to surface treatment, those subjected to surface treatment such as hydrophobic treatment, and the like can be used.

The content of the first particles G1 contained in the coating layer 27 is preferably 10 to 80% by mass, and more preferably 20 to 60% by mass.
If the content of the first particles G1 in the coating layer 27 is less than 10% by mass, the proportion of the first particles G1 is too small compared to the proportion of the binder resin on the surface of the carrier particles. Since the effect of relieving contact with strong impact is small, sufficient durability may not be obtained.
On the other hand, if it exceeds 80% by mass, since the proportion of the first particles G1 is too large compared to the proportion of the binder resin on the carrier surface, the proportion of the binder resin that is the charge generation location becomes insufficient, In some cases, sufficient charging ability cannot be exhibited. Furthermore, since the amount of the first particles G1 is too large compared to the amount of the binder resin, the holding ability of the first particles G1 by the binder resin is insufficient, the first particles G1 are easily detached, and the charge amount and resistance are increased. In some cases, the amount of variation such as the above increases and sufficient durability cannot be obtained.

Here, content in the coating layer 27 of the 1st particle | grains G1 can be calculated | required by following formula (2).

As the second particle G2, at least one kind of particle selected from titanium oxide, zinc oxide, tin oxide, surface-treated titanium oxide, surface-treated zinc oxide, and surface-treated tin oxide is preferably used. It is done.
These particles have an appropriate hardness and are values obtained by measuring 50 points at intervals with the resin used as the carrier coating material and averaging these measured values.
As the first particles G1, for example, alumina particles, silica particles, titania particles, oxidation compatibility is good, and the dispersibility and adhesion are excellent. In particular, titanium oxide or titanium oxide subjected to surface treatment is the second one. It is preferable as the particle G2.
Further, even when a particle matrix other than the above is used, it is possible to improve the dispersibility by subjecting the particle surface to a surface treatment such as a hydrophobizing treatment, If the volume resistivity is within the above range, good effects can be obtained for the same reason as described above.

The content of the second particles G2 contained in the coating layer 27 is preferably 2 to 50% by mass, and more preferably 2 to 30% by mass.
The greater the content of the second particles G2 in the coating layer 27, the greater the effect of increasing the strength. However, when the content of the second particles G2 exceeds 50% by mass, the dispersion state of the second particles G2 inside the coating layer 27 Is significantly worse. When the dispersed state of the particles is deteriorated, the second particles G2 are partially aggregated inside the coating layer 27, so that the effect of the second particles G2 is hardly exhibited on average.
On the other hand, when the content of the second particles G2 in the coating layer 27 is less than 2% by mass, the content of the second particles G2 is too small, so that the effect of adding the second particles G2 cannot be sufficiently obtained.

Content in the coating layer 27 of the 2nd particle | grains G2 can be calculated | required by following formula (3).

As the binder resin used for the carrier particle coating layer 27, either a reaction product of an acrylic resin and an amino resin, or a silicone resin is preferably used.
There is no restriction | limiting in particular as a reaction material of an acrylic resin and an amino resin, Although it can select suitably according to the objective, The crosslinking reaction material of an acrylic resin and an amino resin is suitable.
There is no restriction | limiting in particular as an acrylic resin, Although it can select suitably according to the objective, A thing with a glass transition temperature (Tg) of 20-100 degreeC among these is preferable, and a thing with 25-80 degreeC is more preferable. When the glass transition temperature (Tg) of the acrylic resin is within this range, the acrylic resin has appropriate elasticity, and the friction between the toner and the carrier or between the carriers in the stirring for frictionally charging the developer. Friction can absorb the impact when contacting the binder resin with a strong impact, and the coating layer can be maintained without being damaged.

When the glass transition temperature (Tg) is less than 20 ° C., the binder resin blocks even at room temperature, so that the storage stability is poor and it may not be practically used. On the other hand, when the glass transition temperature (Tg) exceeds 100 ° C., the binder resin is too hard and brittle, and cannot absorb the impact, and the binder resin is scraped from the brittleness and retains the particles. May not be able to be performed and may be easily detached.
The amino resin is not particularly limited and can be appropriately selected from conventionally known amino resins according to the purpose. For example, by using guanamine or melamine, the charge imparting ability is remarkably increased. Can be improved.

There is no restriction | limiting in particular as a silicone resin, According to the objective from the silicone resin generally known, it can select suitably according to the objective, For example, straight silicone resin which consists only of organosilosan bonds, alkyd resin, polyester Examples thereof include silicone resins modified with resins, epoxy resins, acrylic resins, urethane resins, and the like.
Commercially available products can be used as the silicone resin. Examples of the straight silicone resin include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical Co., Ltd .; SR2400, SR2406, and SR2410 manufactured by Toray Dow Corning Silicone. .
Examples of the modified silicone resin include KR206 (alkyd modified), KR5208 (acrylic modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical Co., Ltd .; SR2115 manufactured by Toray Dow Corning Silicone Co., Ltd. Epoxy modified), SR2110 (alkyd modified), and the like.
It is possible to use the silicone resin alone, but it is also possible to simultaneously use a component that undergoes a crosslinking reaction, a charge amount adjusting component, and the like.

As the binder resin used for the carrier particle coating layer 27, in addition to the above-mentioned resins, those generally used as carrier coating resins can be used as necessary. Resin, polystyrene resin, halogenated olefin resin, polyester resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin, vinylidene fluoride Examples thereof include copolymers with vinyl fluoride, fluoroterpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers. These may be used individually by 1 type and may use 2 or more types together.
For example, the coating layer 27 is prepared by dissolving the first particles G1, the second particles G2, the binder resin, and the like in a solvent to prepare a coating solution, and then uniformly coating the coating solution on the surface of the core material 26 by a known coating method. It can be formed by applying and drying, followed by baking. Examples of the coating method include a dipping method, a rolling fluidized bed method, and a spray method.
There is no restriction | limiting in particular as said solvent, Although it can select suitably according to the objective, For example, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cersol butyl acetate, butyl cellosolve etc. are mentioned.
The baking is not particularly limited, and may be an external heating method or an internal heating method. For example, a stationary electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace, etc. The method of using, the method of using a microwave, etc. are mentioned.

The volume average particle size of the carrier core material 26 used in this embodiment is not particularly limited, but the volume average particle size is 20 μm or more from the viewpoint of carrier adhesion to the photoreceptor 1 and prevention of carrier scattering. From the viewpoint of preventing abnormal images such as carrier streaks and preventing deterioration of image quality, those having a thickness of 100 μm or less are preferable. It can respond more suitably.
There is no restriction | limiting in particular as the core material 26, According to the objective, it can select suitably from what is known as a two-component carrier for electrophotography, For example, a ferrite, magnetite, iron, nickel is mentioned suitably. Considering the environmental impact that has been remarkably advanced in recent years, if it is ferrite, for example, Mn ferrite, Mn—Mg ferrite, Mn—Mg—Sr ferrite, etc. are used instead of conventional copper-zinc ferrite. Is preferred.
Specifically, MFL-35S, MFL-35HS (manufactured by Powder Tech), DFC-400M, DFC-410M, and SM-350NV (manufactured by Dowa Iron Industries Co., Ltd.) are preferable examples.

In the carrier of the present invention, the volume resistivity value is preferably 1 × 10 ¹¹ to 1 × 10 ¹⁶ Ω · cm, more preferably 1 × 10 ¹² to 1 × 10 ¹⁴ Ω · cm.
When the volume resistivity of the carrier is lower than 1 × 10 ¹¹ Ω · cm, when the developing gap (the closest distance between the photosensitive member and the developing sleeve) becomes narrow, charge is induced in the carrier and carrier adhesion occurs. It becomes easy to do. When the linear velocity of the photosensitive member and the linear velocity of the developing sleeve are large, a tendency of deterioration is observed. In addition, it is remarkable when an AC bias is applied. Usually, a color toner developing carrier is generally used having a low resistance in order to obtain a sufficient toner adhesion amount.
By using the carrier having the above resistance range under an appropriate toner charge amount, a sufficient image density can be obtained.
On the other hand, if it is larger than 1 × 10 ¹⁶ Ω · cm, charges having a polarity opposite to that of the toner are likely to be accumulated, and the carrier is charged and carrier adhesion is likely to occur.

The carrier volume specific resistance value can be measured by the following method.
As shown in FIG. 9, a carrier 21 is filled in a cell 21 made of a fluororesin container containing electrodes 22 a and 22 b having a distance between electrodes of 2 mm and a surface area of 2 × 4 cm, and a DC voltage of 100 V is applied between both electrodes, DC resistance is measured with a high resistance meter 4329A (4329A + LJK 5HLVLVWDQFH OHWHU; manufactured by Yokogawa Hewlett-Packard Co., Ltd.).
The carrier volume resistivity is measured by filling the cell until it overflows into the cell, tapping the entire cell 20 times, and then using a horizontal spatula made of a non-magnetic top surface of the cell. Scrape flat along the top edge in one operation. No pressure is required during filling.
The resistivity of the carrier can be adjusted by controlling the amount of the electric resistance adjusting agent or the film thickness of the resin coating layer.

Hereinafter, the present invention will be described with reference to examples. In addition, this invention is not limited to the Example illustrated here. In the following, “parts” represents parts by mass, and “%” represents mass%.
[Production of toner]
(Binder Resin Synthesis Example 1)
724 parts of bisphenol A ethylene oxide 2 mol adduct, 276 parts of isophthalic acid and 2 parts of dibutyltin oxide were placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, and reacted at 230 ° C. for 8 hours under normal pressure. The reaction was further carried out at a reduced pressure of 10 to 15 mmHg for 5 hours, followed by cooling to 160 ° C., 32 parts of phthalic anhydride was added thereto and reacted for 2 hours.
Subsequently, it cooled to 80 degreeC and reacted with 188 parts of isophorone diisocyanate in ethyl acetate for 2 hours, and the isocyanate containing prepolymer (P1) was obtained.
Next, 267 parts of the prepolymer (P1) and 14 parts of isophoronediamine were reacted at 50 ° C. for 2 hours to obtain a urea-modified polyester (U1) having a weight average molecular weight of 64,000.
In the same manner as above, 724 parts of bisphenol A ethylene oxide 2-mole adduct and 276 parts of terephthalic acid were polycondensed at 230 ° C. for 8 hours under normal pressure, and then reacted for 5 hours at a reduced pressure of 10 to 15 mmHg. An unfinished polyester (E1) was obtained.
200 parts of urea-modified polyester (U1) and 800 parts of unmodified polyester (E1) are dissolved and mixed in 2000 parts of an ethyl acetate / MEK (1/1) mixed solvent, and the binder resin (B1) ethyl acetate / MEK is mixed. A solution was obtained.
A part was dried under reduced pressure, and the binder resin (B1) was isolated. The glass transition temperature (Tg) was 62 ° C.

(Polyester resin synthesis example A)
Terephthalic acid: 60 parts dodecenyl succinic anhydride: 25 parts trimellitic anhydride: 15 parts bisphenol A (2,2) propylene oxide: 70 parts bisphenol A (2,2) ethylene oxide: 50 parts Place the flask in a 1 L four-necked round bottom flask equipped with a stirrer, condenser and nitrogen gas introduction tube, set the flask in a mantle heater, and introduce nitrogen gas from the nitrogen gas introduction tube. The temperature was raised in an active atmosphere, and then 0.05 part of dibutyltin oxide was added and reacted at a temperature of 200 ° C. to obtain polyester A. This polyester A had a peak molecular weight of 4,200 and a glass transition temperature (Tg) of 59.4 ° C.

(Master batch production example 1)
Pigment: C.I. I. Pigment Yellow 155: 40 parts Binder resin: Polyester resin A: 60 parts Water: 30 parts The above raw materials were mixed in a Henschel mixer to obtain a mixture in which water was soaked into the pigment aggregate. This was kneaded for 45 minutes with two rolls set at a roll surface temperature of 130 ° C., and pulverized to a size of 1 mmφ with a pulverizer to obtain a master batch (M1).

(Toner Production Example A)
In a beaker, 240 parts of the above binder resin (B1) in ethyl acetate / MEK solution, 20 parts of pentaerythritol tetrabehenate (melting point 81 ° C., melt viscosity 0.025 Pa · s (25 cps)), master batch (M1) Eight parts were added and stirred at 12000 rpm with a TK homomixer at 60 ° C. to uniformly dissolve and disperse the toner material solution.
In a beaker, 706 parts of ion exchange water, 294 parts of hydroxyapatite 10% suspension (Superite 10 manufactured by Nippon Kagaku Kogyo Co., Ltd.) and 0.2 part of sodium dodecylbenzenesulfonate were uniformly dissolved.
Next, the temperature was raised to 60 ° C., and the toner material solution was added and stirred for 10 minutes while stirring at 12000 rpm with a TK homomixer.
The mixture was then transferred to a Kolben equipped with a stirrer and a thermometer, heated to 98 ° C. to remove the solvent, filtered, washed, dried, and then classified by air to obtain toner particles.
Next, 100 parts of the toner particles were mixed with 1.0 part of hydrophobic silica and 1.0 part of hydrophobic titanium oxide using a Henschel mixer to obtain “Toner A”.

An ultrathin section of this “toner A” was prepared, and a cross-sectional photograph (magnification × 100,000) of the toner was taken using a transmission electron microscope (H-9000H manufactured by Hitachi, Ltd.), and randomly selected from the photograph. The average value was determined from the dispersion diameter of 100 colorant portions. Here, the dispersion diameter of one particle is the average of the longest diameter and the shortest diameter, and the aggregate itself is one particle in the aggregated state.
The average dispersed particle diameter of the colorant was 0.40 μm. The colorant having a dispersed particle diameter of 0.7 μm or more was 4.5%.
Next, the particle size of “Toner A” was measured using a particle size measuring device “Coulter Counter TA2” manufactured by Coulter Electronics Co., Ltd. with an aperture diameter of 100 μm. The diameter (Dn) was 5.1 μm.
Subsequently, the circularity of “toner A” was measured as an average circularity by a flow type particle image analyzer FPIA-1000 (manufactured by Toa Medical Electronics Co., Ltd.). In the measurement, 0.1 to 0.5 ml of a surfactant (alkylbenzene sulfonate) as a dispersant is added to 100 to 150 ml of water from which impure solids have been removed in advance, and a measurement sample is further added to 0.1 to 0.5 ml. About 0.5 g was added, the dispersion treatment was performed for about 1 to 3 minutes with an ultrasonic disperser, and the measurement liquid adjusted to a dispersion concentration of 3000 to 10,000 / μl was set. The resulting “Toner A” had a circularity of 0.96.

[Creation of carrier]
(Carrier Production Example I)
Acrylic resin solution (solid content concentration: 50 mass%) 1500 parts guanamine solution (solid content 70 mass%) 450 parts aminosilane (solid content concentration: 100 mass%) 4 parts alumina particles A (volume average particle size 0.37 μm) 1300 Part titanium oxide particles (volume average particle size 0.015 μm) 500 parts Electric resistance adjusting agent 200 parts Toluene 6000 parts The above materials were dispersed for 10 minutes with a homomixer to prepare a resin layer forming solution. Ferrite particles having a volume average particle diameter of 35 μm are used as a carrier core material, and 30 g of the above resin solution is applied to the surface of the core material at a temperature of 55 ° C. by a Spira coater (Okada Seiko Co., Ltd.) so that the thickness h is 0.15 μm. It was applied at a rate of / min and dried. The layer thickness was adjusted depending on the liquid amount. The obtained carrier was baked by standing in an electric furnace at 150 ° C. for 1 hour, and after cooling, it was crushed using a sieve having an opening of 100 μm to obtain Carrier I. The average thickness T was 0.41 μm.

The volume average particle diameter of the core material was measured using a Microtrac Particle Size Analyzer (Nikkiso Co., Ltd.) SRA type with a range setting of 0.7 μm or more and 125 μm or less.
The average thickness h (μm) of the resin portion in the coating layer is obtained by observing the cross section of the carrier using a transmission electron microscope (TEM), and the thickness ha of the resin portion existing between the core material surface and the particles, The thickness hb of the resin part existing between the particles and the thickness hc of the resin part on the core material and the particle are measured at 50 points along the carrier surface at intervals of 0.2 μm, and the obtained measurement values are averaged. Asked.
The thickness T (μm) from the core material surface to the coating layer surface is observed with a transmission electron microscope (TEM), and the thickness T from the core material surface to the coating layer surface is determined by observing the carrier cross section. Were measured at intervals of 0.2 μm, and the obtained measured values were averaged.

[Developer 1]
Using 7 parts by mass of toner A obtained in the toner production example and 93 parts of carrier I obtained in the carrier production example, the mixture was stirred for 10 minutes with a mixer to prepare a developer to be accommodated in the developing machine. Further, 80 parts of the toner A obtained in the toner production example and 20 parts of the carrier I obtained in the carrier production example were stirred for 10 minutes with a mixer to prepare a replenishment developer.
In order to make an acceleration test, the developer for replenishment was stored in the developer container, and then left to stand for 168 hours, and then gently placed in the developer replenisher immediately before the image increase output.

[Developer 2]
As a replenishment developer, a replenishment developer was prepared in the same manner as Developer 1, except that 98 parts of toner A obtained in the toner production example and 2 parts of carrier I obtained in the carrier production example were used. .
[Developer 3]
As a replenishment developer, a replenishment developer was prepared in the same manner as Developer 1, except that 69 parts of toner A obtained in the toner production example and 31 parts of carrier I obtained in the carrier production example were used. .

[Developer 4]
The developer for replenishment is the same as developer 1 except that 16 parts of toner A obtained in the toner production example and 84 parts of carrier I obtained in the carrier production example were used as the developer contained in the developing machine. Was made.
[Developer 5]
For replenishment in the same manner as Developer 1 except that 1 part by mass of toner A obtained in the toner production example and 99 parts by mass of carrier I obtained in the carrier production example were used as the developer contained in the developing machine. A developer was prepared.

[Image forming apparatus, developer supply apparatus, and peripheral apparatus]
The image forming apparatus, developer replenishing apparatus and peripheral apparatus shown in FIGS. 1 to 7 were used. The replenishment amount of the developer was set so as to be calculated and determined from the change in the toner density in the developing device due to the image output, taking into account the toner concentration of each replenishment developer.

Example 1
Using the developer 1, the image forming apparatus, the developer replenishing apparatus, and the peripheral devices, 100k images were output. As the output image, an image having an image area on paper of 5% and an image of 20% were alternately used every 2k sheets.
As a result of image output, a good image could always be obtained even when the developer was supplied to the developing device.
(Example 2)
The same operation as in Example 1 was performed except that Developer 2 was used instead of Developer 1.
As a result of image output, the image density gradually decreased from about the 80kth sheet. However, the image was within the allowable range.

(Example 3)
The same operation as in Example 1 was performed except that Developer 3 was used instead of Developer 1.
As a result of image output, it seemed that the air pump drive motor and screw pump for transporting the replenishment developer were under load, but a good image could always be obtained.
Example 4
The same procedure as in Example 1 was performed except that developer 4 was used instead of developer 1.
As a result of image output, toner scattering occurred and the inside of the image forming apparatus was soiled, but the output image was within an allowable range.

(Example 5)
The same operation as in Example 1 was performed except that Developer 5 was used instead of Developer 1.
As a result of image output, the image density was slightly thinner than that of Example 1. However, it was possible to stably obtain an image within an allowable range up to the 100kth sheet.
(Comparative example)
The test was performed in the same manner as in the example except that the magnetic permeability sensor 270 and the replenishment developer stirring device 271 shown in FIGS. 1 and 2 were not provided.
As a result of the image output, immediately after the developer was replenished to the developing device, irregularly dark and dark image densities appeared. The stability of the image was outside the acceptable range.

1 (1a, 1b, 1c, 1d) Photoconductors 2A, 2B, 2C, 2D Image forming unit 3 Charging unit 301 Charging roller 6 Exposure device 7 Paper feed cassette 8 Transfer belt 9 Fixing device 10 (10A, 10B, 10C, 10D) ) Developing device 11a, 11b Conveying screw 12 Developing roller 13 Layer thickness regulating member 14 Developer accommodating portion 15 Housing 15a Replenishment port 21 Cell 22a Electrode 22b Electrode 23 Carrier 26 Core material 27 Covering layer 100 Device main body 200A, 200B, 200C, 200D Developer supply device 220 Developer supply device 221 Transport tube 222 Container holder 223 Screw pump 224 Rotor 225 Stator 226 Drive motor 227 Universal joint 230 Developer storage device 231 Developer storage member 232 Cap portion 233 Sealing material 240 Slurry 241 Inner pipe 241a Developer flow path 242 Outer pipe 244 Air flow path 246a, 46b Air supply port 247 Toner outlet 260 Air supply means 260a, 260b Air pump 261a, 261b Air supply path 262a, 262b Open / close valve 300 Developer discharge device 330 Recovery Container 331 Discharge Pipe 51 Discharge Path 52 Discharge Roller Pair 53 Discharge Tray 54 Paper Adsorption Roller 55 Resist Roller Pair ha, hb, hc Cover Layer Thickness T Average Thickness from Core Material Surface to Cover Layer Surface

Japanese Patent Publication No. 2-21591 Japanese Patent Laid-Open No. 3-145678 Japanese Patent Laid-Open No. 11-223960

Claims (7)

Using an electrophotographic developer carrier composed of core material particles and a coating layer covering the particles and a toner, a replenishment developer composed of toner and carrier is replenished to the developing device containing the toner and the carrier. In the electrophotographic developer replenishing method using the developer replenishing device for replenishing the developing device from the developer containing container and discharging the developer remaining in the developing device ,
The developer replenishing device is detachably equipped with the replenishment developer container.
The replenishment developer container is filled with a replenishment developer, the replenishment developer is sucked with a suction pump and supplied to the developing device,
And a developer agitating mechanism for reducing a deviation in toner concentration of the replenishment developer accommodated in the replenishment developer accommodating container,
The mass ratio of the carrier in the replenishment developer in the transport tube replenished to the developing device is detected, and the mass ratio and the mass of the carrier in the replenishment developer accommodated in the replenishment developer container Compare with the ratio ,
When there is a difference between these mass ratios, the operation of the developer agitating mechanism is controlled to reduce the unevenness of the toner concentration of the replenishment developer accommodated in the replenishment developer accommodating container. Photographic developer supply method. 2. The electrophotographic developer replenishing method according to claim 1, wherein a magnetic permeability sensor is used to detect a mass ratio of a carrier in a replenishing developer replenished to the developing device. The method for replenishing electrophotographic developer according to claim 1 or 2 is used.
  An electrophotographic developing device. The electrophotographic developing device according to claim 3 is used.
  An electrophotographic developing method characterized by the above. The electrophotographic development method according to claim 4,
The mass ratio of the carrier in the replenishment developer accommodated in the replenishment developer container is 3% by mass or more and less than 30% by mass.
An electrophotographic development method characterized by the above . The electrophotographic development method according to claim 4 or 5,
The mass ratio of the carrier in the developer accommodated in the developing device is 85% by mass or more and less than 98% by mass.
An electrophotographic development method characterized by the above . In a process cartridge comprising at least a photoreceptor and developing means,
  An image is formed using the electrophotographic development method according to claim 4.
  A process cartridge characterized by that.

Images