JP2008096623A - Developer for replenishment and replenishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer for replenishment and a replenishment developer replenishing device capable of stably and efficiently supplying a developer for replenishment including toner and carrier from the replenishment developer container to a developer tank by air conveyance without segregating the carrier in the developer for replenishment. <P>SOLUTION: The developer for replenishment, in which the carrier has specific gravity of 2.5-4.2 and a 50% particle diameter on a volume basis (D50) of 15-70 μm is transported together with an air flow from the replenishment developer container and introduced into the developer tank in an image forming apparatus. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a two-component development in which replenishment developer containing at least toner and carrier is developed while replenishing the developing device, and excess toner and carrier inside the developing device are discharged from the developing device as necessary. The present invention relates to a replenishment developer for use in a developer development method (hereinafter sometimes abbreviated as an auto-refresh development method), and a replenishment developer replenishment device that transfers the replenishment developer to a developing tank together with an air flow. . More specifically, the replenishment developer can be automatically supplied to the developing unit, and can be completely discharged from the replenishment developer container and can be stably replenished from the replenishment developer container to the developing tank. The present invention relates to a developer and a developer supply device for supply.

  In recent years, in image forming methods using electrophotographic technology such as copying machines and printers, even higher developer durability (longer life, lower running costs), higher image quality, higher reproducibility, and There is a demand for machine downsizing, longer life, and maintenance-free improvement. As one method of achieving such a requirement, a small amount of carrier is mixed with the toner in the replenishment developer container, and at the same time as the replenishment of toner, a small amount of carrier is replenished into the developing tank. An auto-refresh development system has been proposed in which the deterioration of the developer is prevented by substituting this with a deteriorated carrier (see, for example, Patent Documents 1 and 2).

  On the other hand, a screw pump having a rotor that moves the developer for supply in the axial direction by rotating, a passage that wraps the rotor inside, and a fixed stator that contacts and engages the rotor inside the passage; This replenishment developer transports a mixture of replenishment developer and air through a flexible pipe using air supply means for supplying air for fluidizing the replenishment developer moved by the screw pump. A developer supply device is known (see, for example, Patent Document 3).

  Furthermore, air is introduced into the replenishment developer container to fluidize the agent, and the fluidized replenishment developer is discharged by the pressure of the air that has flowed into the replenishment developer container. There is known a replenishment developer replenishing device that is transported together with an air flow by means (see, for example, Patent Document 4 and Patent Document 5).

  In these transfer systems, the replenishment developer stored can be transported via a flexible pipe, etc., so there is no restriction on the installation position of the replenishment developer container and replenishment device, and replenishment with a simple configuration. There is an advantage that the developer can be reliably transferred.

  Further, since it is an air conveying means, there is an advantage that the load on the toner and the carrier is small.

  However, in the replenishment developer transfer system, the replenishment developer including the carrier used in the auto-refresh development system is in a state where the replenishment developer is mixed with air and fluidized by the air conveying means. Carrier is segregated in the replenishment developer container and / or replenishment device for transporting, and further flowing air into the replenishment developer container and fluidizing and discharging the replenishment developer. The distribution is not uniform, and a problem that a large amount or a small amount of toner and a carrier are easily supplied instead of an appropriate amount is easily generated in the developing tank.

  Further, the carrier remains in the pipe, so that the supply of the replenishment developer to the developing tank is reduced, or clogging is likely to occur and the replenishment cannot be easily performed.

  Furthermore, the carrier remains in the suction pump used as the air conveying means, and the members in the pump, particularly the rubber stator with low wear resistance, are easily worn, and the durability of the suction pump deteriorates. Or the transferability of the replenishment developer may be affected.

  In this case, the amount of developer in the developing tank increases or decreases, and the toner density in the developing tank cannot be stably maintained at the reference value. Furthermore, in the auto-refresh development method, when the amount of developer in the developing tank increases or decreases, the fresh carrier from the replenishment developer and the carrier deteriorated due to long-term use in the developing tank cannot be smoothly exchanged. As a result, even with the auto-refresh development method, it is not possible to stabilize the image density by suppressing the change in the charge amount of the toner in the developing tank. Furthermore, there is a problem that fogging occurs in the white background portion of the image, image uniformity, gradation deterioration, in-machine contamination due to toner scattering, and deterioration of image quality.

  Further, since the conventional replenishment developer including the carrier has poor fluidity, even when it is determined by the remaining amount detection that there is no replenishment developer in the replenishment developer container, a large amount of replenishment developer is contained in the container. The problem that the replenishment developer remains is likely to occur.

Japanese Patent Laid-Open No. 3-145678 JP 2001-330985 A JP 7-219329 A JP 2000-47464 A JP 2000-147844 A

The present invention
1) Even when a replenishment developer composed of toner and a carrier is transported by a replenishing device having an air conveying means, it can be smoothly transported in a uniform state without causing segregation of the carrier;
2) Further, even in a developer supply device for supply having an air inflow means for fluidizing and supplying the developer for replenishment filled in the developer storage container for supply, the carrier segregation is caused. It can be transported in a uniform state without occurrence and without deteriorating the surface property of the carrier, the surface property of the toner, and the external additive adhesion state;
3) As a result, in the auto-refresh development method, even when used for a long time, toner scattering hardly occurs, the toner charge amount in the developing device is stable, and the image quality, image uniformity, and image density stability are excellent. High quality images without fogging can be obtained;
It is an object of the present invention to provide a replenishment developer and a replenishment developer replenishment device.

  As a result of intensive studies, the present inventors have found that the above requirements are satisfied by using the following replenishment developer, and have reached the present invention.

That is, an air conveying means for supplying a replenishment developer composed of at least toner and a carrier by an air flow to a developing device of an image forming apparatus for developing an image by developing a latent image on the latent image carrier with toner. In the replenishment developer replenishing device provided with the replenishment developer storage container connected to the air conveying means, the problem is solved by using a replenishment developer satisfying the characteristics 1) and 2). .
1) The volume-based 50% particle size (D50) of the carrier is 15 to 70 μm.
2) The true specific gravity of the carrier is 2.5 to 4.2.

  The replenishment developer and the replenishment developer replenishment device according to the present invention are for replenishment having a stable carrier concentration without segregation of the carrier because the carrier in the replenishment developer has an appropriate specific gravity and particle size. The developer can be smoothly discharged and transferred from the replenishment developer container to the developing tank. Therefore, stable image density and image quality can be obtained over a long period of time. Further, the replenishment developer replenishing device of the present invention is such that the carrier in the replenishment developer has an appropriate specific gravity and particle diameter, and the replenishment developer is discharged and transferred by the air conveying means. And the load on the carrier is very small. For this reason, it is possible to obtain a remarkably stable image density and image quality over a long period of time as compared with a replenishment developer having a conventional carrier and a replenishment device for replenishing it. Further, since the replenishing device can be flexibly arranged in the main body, the device can be downsized and the device cost can be reduced as compared with the conventional device having the auto-refresh development method.

  Further, since the carrier in the developer for replenishment has an appropriate specific gravity and particle size, the wear resistance on the member in the suction pump used as the air conveying means is lower than that of the conventional carrier. For this reason, the durability of the pump is remarkably improved, and the life of the main body, productivity and maintenance-free required for the auto-refresh development method can be greatly improved.

  The present inventors are provided with a replenishment developer comprising at least toner and a carrier used in the auto-refresh development system, an air conveying means for transferring the developer to the developing tank by an air flow, and a connection to the air conveying means. In the replenishing developer replenishing device provided with the replenishing developer container, the above-mentioned problems are solved as a result of intensive studies on the carrier particle size, specific gravity, and flowability (transportability) of the replenishing developer. The inventors have found that a replenishing developer and a replenishing developer replenishing device can be obtained, and have completed the present invention.

  The present invention is described in further detail below.

  FIG. 1 is a schematic view schematically showing a state where a replenishment developer composed of at least toner and a carrier filled in a replenishment developer container 40 is transferred to a developing device of an image forming apparatus. The replenishment developer container 40 shown here is an example that can be used in the present invention, and the container will be described in detail later.

  The developing device P includes a developing tank 117 containing a two-component developer D obtained by mixing toner and carrier, stirring screws 10 and 11 for stirring and mixing the developer D, and a developing sleeve 8. The developing sleeve 8 is disposed to face the electrostatic charge image carrier 1 of the latent image carrier. The electrostatic charge image carrier 1 is rotationally driven in the direction indicated by the arrow in FIG. 1, and an electrostatic latent image is formed on the surface thereof.

  As the agitating screws 10 and 11 rotate, the developer D in the developing tank 117 is agitated, and the toner and the carrier are frictionally charged with opposite polarities. The developer D is supplied to the peripheral surface of the developing sleeve 8 that is rotationally driven, and the supplied developer D is carried on the peripheral surface of the developing sleeve 8 and rotates in the rotating direction by the rotation of the developing sleeve 8. Be transported. Next, the amount of the developer D thus transported is regulated by the regulation blade 12, and the regulated developer D is conveyed to the development region between the electrostatic charge image carrier 1 and the development sleeve 8. Here, the toner in the developer D is electrostatically transferred to the electrostatic latent image on the surface of the electrostatic image carrier 1, and the electrostatic latent image is visualized as a toner image.

  When the image forming operation as described above is repeated, the toner in the developer D accommodated in the developing tank 117 in the developing device of FIG. 1 is gradually consumed, and the ratio of the toner to the carrier, that is, the toner density is increased. It goes down. The change in the toner density is caused by the toner density detection sensor (not shown) provided in the developing tank 117 and / or the density transition of the reference image on the electrostatic latent image carrier and / or the intermediate transfer body. Is feedback-controlled (patch detection) so that it always falls within the appropriate range required for development.

  When it is detected by the above control that the toner concentration of the developer D in the developing tank 117 is lowered, the replenishment developer container 40 in the replenishment developer container 40 detachably set in the image forming apparatus main body is used. The developer is supplied into the developing tank 117 via the supply device of the present invention. As a result, the toner concentration of the developer D in the developing tank 117 can be maintained within a certain range.

  This replenishment developer replenishment device is provided with a replenishment developer feed passage 3 between the replenishment developer container 40 and the developing device P, and the replenishment developer is replenished to the developer tank by an air flow therein. To do. According to this apparatus, the replenishment developer can be replenished to the developing tank even if the replenishment developer container 40 and the developing device P are arranged apart from each other. In FIG. 1, air is preferably sent from an air inflow unit 50 to the replenishment developer container 40. FIG. 2 shows a cross-sectional view as an example of a supply developer container (details will be described later). The air is jetted into the replenishment developer container 40 and passes through the replenishment developer layer while diffusing, thereby promoting fluidization of the replenishment developer. This also prevents the generation of agglomerates composed of toners and / or toner and carrier, so that the replenishment developer can be replenished to the developing tank more reliably.

  Further, not only sending air into the replenishment developer container 40 but also applying appropriate vibrations and impacts to the replenishment developer container 40 can stabilize the replenishment developer with extremely poor fluidity. Effective for suction and transfer. Further, moderate vibration and impact are preferable because they have the effect of preventing toner from coagulating with each other and / or toner and carrier and stably transporting the replenishment developer to the replenishment developer feed passage 3. As these specific means, conventionally known methods such as intermittent impact application using a cam and lever, and vibration addition using a motor or solenoid may be used.

  The replenishment developer feed passage 3 is formed by connecting the replenishment developer container 40 and the developing tank with a replenishment developer feed means having an arbitrary length. Specifically, the connection between the one end of the replenishment developer delivery means and the discharge port of the replenishment developer container 40 is connected to the other end of the replenishment developer delivery means and the developing tank. It is formed between the parts.

  The replenishment developer feed means comprises at least a means for forming an air flow (referred to as an air transport means) and a replenishment developer feed pipes 49-1, 2 (FIGS. 2-4). The flow pipes 4949-1 and 2949 (FIGS. 2 to 4) are elongated, and their length is arbitrary. Accordingly, the replenishment developer feed means is involved in discharging the replenishment developer from the replenishment developer container 40 and replenishing the developer tank, and between the replenishment developer container 40 and the development tank. This is a general term for the products obtained by connecting the components such as the air conveying means and the replenishment developer flow pipe 49 which are present. Further, the passage formed by connecting in this way and passing the replenishment developer is referred to as a replenishment developer feed passage 3.

  In the present invention, a means for sucking air in the replenishment developer storage container such as a suction pump (referred to as air transport means) is used as the air transport means. When this air conveying means is operated, a one-way air flow toward the developing tank is formed in the replenishment developer flow passage 3, and the replenishment developer is fed by this air flow to the replenishment developer flow passage 3. Through the interior, the replenishment developer according to the present invention is replenished to the developing tank without the carrier or the like staying on the way. By adjusting the operation of the air conveying means, the strength of the air flow can be adjusted and the amount of replenishment developer to be replenished can be controlled. In this case, as described above, it is preferable to fluidize the replenishment developer in the container by adding a means (air inflow means 50) for blowing air into the replenishment developer storage container such as an air pump. is there.

  The novel replenishment developer replenishing device of the present invention will be described based on the following three specific examples. According to this example, the replenishment developer feed means, the components constituting the replenishment developer feed means, and the replenishment developer feed distribution The path 3 is not limited. Further, the replenishment developer container 40 may have the replenishment developer discharge port facing downward, upward, or obliquely upward or obliquely downward. The developer container 40 may be placed in any direction.

In the replenishment developer replenishing device of the present invention, the method (1) is adopted, and the method (3) is more preferably adopted.
(1) Method of sucking out the developer for replenishment in the container together with air (suction method)
(2) Method of introducing air into the replenishment developer container (blowing method)
(3) Combined method of (1) and (2) above

  First, the suction method (1) will be described with reference to FIGS. FIG. 3 is a conceptual diagram when the suction pump 31 is used as the air conveying means. The feature of the suction system in this example is that a suction pump 31 as a suction means is arranged between the replenishment developer container 40 and the developing device P, and each is connected by a replenishment developer flow pipe 49, The replenishment developer is sucked out of the replenishment developer container 40 by the suction pump, and the replenishment developer is replenished to the developing tank together with the air flow.

  FIG. 4 is a sectional view of a configuration showing an example of a suction pump used in the suction method of the present invention. The suction pump 31 is a suction type uniaxial eccentric screw pump called a so-called Mono pump, and has a fixed hollow elastic member and a helically bent rigid shaft in contact with the inner wall as main parts. In other words, a rotor made in the shape of a screw eccentric with a rigid material such as metal, a stator that is made of a rubber material and is fixed in a screw shape with two or more insides, and a powder that wraps these powders It is comprised from the holder made from the resin material etc. which form the transfer path. By rotating the rotor, a strong self-priming force is generated in the pump, and it becomes possible to suck in the airflow containing the replenishment developer.

  More specifically, a pump body 30 provided with a rotating shaft 34 (rotor) made of a torsion rod in a stator 35 having a shallow spiral groove on the inner wall, and an air introduction pipe 33 provided on the discharge side of the pump body 30. And a delivery section 38 having a feed pipe 37. On the suction side of the pump body 31, a toner suction pipe 36 having a replenishment developer suction port is connected to a replenishment developer discharge port 45 of the replenishment developer container 40 via a replenishment developer feed pipe 49-1. It is connected. A feed pipe 37 having an air discharge port of the delivery section 38 is connected to the developing device P via a replenishment developer feed pipe 49-2.

  The connection between the suction pump and the developing tank may be made directly without using the replenishment developer flow pipe 49-2. In particular, in the case of a system using a suction pump, even if the replenishment developer container 40 is installed at a position considerably away from the replenishment developer container 40, the function can be sufficiently exhibited by using the replenishment developer of the present invention.

  Therefore, in the suction system of this example, the replenishment developer feed pipes 49-1, 49-2 and the suction pump constitute a replenishment developer feed means, and the replenishment developer feed pipe 49-1, The replenishment developer feed passage 3 is formed by the suction pipe 36, the feed pipe 37 and the replenishment developer feed pipe 49-2 in the suction pump.

  The replenishment developer feed passage 3 formed by connecting the replenishment developer discharge port 45 of the replenishment developer container 40, the suction pump 31, and the developing device P is connected with as little gap as possible. It is particularly desirable to be in a state, that is, in a sealed state. In particular, it is important that the connection between the replenishment developer discharge port 45 of the replenishment developer container 40 and the replenishment developer feed pipe 49-1 is in such a state.

  In such a connected state, the rotary shaft 34 of the pump body 30 is rotated while supplying air of a predetermined pressure from the air introduction pipe 33 to the delivery part 38 of the suction pump 31. Due to the rotation of the rotating shaft 34, the replenishment developer accommodated in the replenishment developer container 40 is sucked through the replenishment developer suction port by compressing the replenishment developer. It is sent to the sending unit 38 without any problem. The replenishment developer sent to the delivery section 38 is diffused and fluidized by the air flow sent from the air introduction pipe 33, and passes through the replenishment developer feed pipe 49-2 from the air discharge port of the feed pipe 37. The developer P is replenished.

  In the suction method, the discharge amount of the replenishment developer can be controlled by adjusting the rotation speed and rotation time of the pump. The replenishment developer of the present invention is excellent in that the replenishment accuracy of the replenishment developer can be particularly improved because it is difficult for the carrier to segregate during replenishment.

  In the replenishment developer container 40 of the present invention, when a bag portion (container body or inside the container body) formed of a flexible material and a replenishment developer discharge port is used, the bag portion The capacity changes due to deformation by the pressure of air. When such a container is applied to the suction system, there is a concern that if the container is sucked, the flexible materials constituting the bag portion are brought into close contact with each other and the replenishment developer is not discharged.

  However, in the case of a replenishment developer excellent in transportability including a carrier having an appropriate particle size and specific gravity according to the present invention described later, replenishment from the central portion of the replenishment developer container 40 when the air conveying means is operated. Since the developer is sucked accordingly, the above-described problems are unlikely to occur.

  Next, the blowing method (2) will be described. FIG. 2 is a schematic diagram illustrating an example of the blowing method. The air inflow means includes a nozzle 43, a replenishment developer feed pipe 49 and an air supply pipe 44 in addition to the blowing air pump 51. These replenishment developer feed pipe 49 and air supply pipe 44 are replenished respectively. The developer container 40, the blowing air pump, the nozzle, and the air conveying means are connected.

  The sizes and materials of the replenishment developer flow pipe 49 and the air supply pipe 44 are arbitrary and are not limited, but each of the replenishment developer storage container 40, the blowing air pump, and the air conveyance means (air conveyance means 30). Since the arrangement can be taken freely and piping can be made in any direction, up, down, left and right, a flexible one is preferable. The flexible tube has a diameter of, for example, 4 to 10 mm. For example, polyurethane, nitrile, EPDM, silicon, and the like, developer resistance for supply (toner adhesion, abrasion resistance, deterioration resistance, etc.) It is extremely effective to use a material made of a material such as rubber excellent in

  The nozzle 43 is a columnar body made of a material such as plastic or metal, and a replenishment developer discharge pipe portion 46 and a blown air flow path pipe portion 48 which are built in the length direction of the columnar body are provided with a columnar body. It is formed so as to protrude from both end faces or side faces.

  The nozzle of this example is provided with a replenishment developer discharge port 45 on one end side of the replenishment developer discharge pipe part 46, and the blowing air flow path pipe part 48 is annular around the replenishment developer discharge pipe part 46. Preferably, these are formed so as to surround each other and are integrally formed. The nozzle exterior portion 47 is arranged such that the replenishment developer discharge port 45 provided at one end of the replenishment developer discharge pipe portion is located in the replenishment developer accommodating portion of the replenishment developer accommodating container 40. It is connected to a fitting portion constituting a toner discharge port of the replenishment developer container 40.

  The projecting end of the replenishment developer discharge pipe 46 without the discharge port 45 is connected to the replenishment developer feed pipe 49, and the other end side of the replenishment developer feed pipe 49 is an air conveying means. The connection member fixed to the replenishment developer receiving port of the developing device P is connected to the developing device P through 30. The connecting member is provided with a filter that allows air to pass therethrough and does not transmit the toner and the carrier.

  On the other hand, the projecting other end portion of the blow-in air flow channel tube portion 48 is connected to the air supply tube 44, and the other end portion of the air supply tube 44 is connected to the air pump 51 as an air inflow unit attached to the image forming apparatus main body. Connected to the air outlet.

  In this way, the nozzle 43 is fitted with the replenishment developer discharge port 45 of the replenishment developer container 40, and the replenishment developer discharge pipe 46 and the connecting member of the developing device P are connected to the replenishment developer flow. A replenishment developer feed flow path 3 is formed by being connected via a pipe 49.

  The replenishment developer container 40 shown here is an example that can be used in the present invention, and the container will be described in detail later.

  The discharge port of the replenishment developer container 40 is faced downward, and one end side, that is, the front end portion of the nozzle 43 is inserted and fitted into a mechanism 42 for improving adhesion formed at the replenishment developer discharge port. . In the replenishment developer storage container 40 of this example, a plate-shaped elastic member having a slit formed in advance and having a size for embedding the space on the inner surface of the cylindrical body, which is a discharge port, is fixed to improve adhesion. A mechanism 42 is formed.

  The elastic member thus fixed provides a sealing effect that does not leak the replenishment developer from the replenishment developer container 40 even if a slit is formed. At the same time, when the tip of the nozzle 43 is inserted so as to protrude into the replenishment developer container 40, the elastic member is deformed, and there is no gap between the nozzle 43 and the elastic member, so that the airtightness is maintained as a whole, and the air is maintained. The flow of replenishment developer by the flow is ensured.

  When air is thus introduced into the replenishment developer container 40, the powdery replenishment developer of the present invention inside thereof is fluidized without segregation of the carrier. Since the introduction of air is in the fluidization of the replenishment developer, it is not necessary to increase the pressure in the container 41 by this, but it may be increased. In this case, the replenishment developer that has been fluidized by the amount of the increase in pressure or beyond is supplied to the outside of the replenishment developer container 40 through the replenishment developer discharge port 45 of the replenishment developer discharge pipe 46. Discharged. The discharged replenishment developer is guided to the replenishment developer feed pipe 49 together with air.

  If the above-mentioned blowing method is the replenishment developer of the present invention, even if the replenishment developer is stored in the container for a long period of time and is in a tight state, Since it is effective in fluidizing without segregation, it is an excellent method in that the supply developer can be discharged smoothly and stably.

  Next, the combination formula (3) will be described using an example. In this method, the suction method (1) and the blowing method (2) are used in combination. In the blowing method described above, for example, between the replenishment developer flow tube 49 and the developing device P, for example, FIG. The suction pump 31 as shown in FIG.

  Therefore, the replenishment developer feeding means in this example is the same except that a suction pump is added in the blowing method described above. When the suction pump 31 is operated by being arranged and connected in this manner, the replenishment developer is sucked from the replenishment developer discharge port 45 of the replenishment developer discharge pipe portion 46 constituting the nozzle 43. At this time, the air pump 51 is operated at the same time to send air into the replenishment developer container 40 from the air flow path pipe section 48.

  Even when the replenishment developer accumulates in the vicinity of the replenishment developer discharge port 45, the replenishment developer is loosened by the supplied air to prevent blockage due to lump, and further aggregation. Even if it is done, it will be crushed. The replenishment developer is then sucked by the suction pump 31 and replenished to the developing device P through the replenishment developer feed pipe 49.

  In the combined type of this example, the replenishment developer feeding means includes a blowing air pump 51, a suction pump 31, a nozzle 43, a replenishment developer feeding pipe 49 and an air supply pipe 44. The nozzle wall portion 47 is fitted into the replenishment developer discharge port 45 of the replenishment developer container 40, and the replenishment developer feed pipe 49, the suction pump 31, and the developing device P connection member of the nozzle portion 17. Are connected via a replenishment developer flow tube 49 to form a replenishment developer flow passage 3.

  Also in this method, it is necessary to pay sufficient attention to the sealing property of the replenishment developer flow passage 3 as in the above-described two methods. The combined system is an excellent system in that the replenishment developer always fluidized by the suction pump is sucked, so that the discharge and replenishment of the replenishment developer can be stably maintained with high accuracy.

  Note that the timing of driving the pump and supplying air by the pump is important in order to ensure the reliability of replenishment developer transfer at the time of replenishment of the replenishment developer. It is important that the air is supplied before the pump is driven (the air supply after the stop of driving is better). Thus, the replenishment developer, particularly the carrier, is prevented from remaining in the transfer member (tube or the like), and the replenishment developer can be stably replenished.

  The supply of air into the replenishment developer storage container may be the same as the supply timing to the pump, but may be synchronized with a replenishment developer replenishment signal or intermittent supply thereof.

  Next, an example of the supply developer container 40 that can be used in the present invention will be described. The replenishment developer container 40 is composed of a bag part (container body) composed of a flexible single-layer or multi-layer sheet and a connection part (mouth part: replenishment developer discharge port). It is preferable that the replenishment developer discharge port has a cylindrical portion that can be fitted into the replenishment developer feed pipe and can maintain the fitted state.

  Here, the “fitting portion that can be fitted to the replenishment developer flow tube and can maintain the fitted state” means a replenishment developer discharge port connected to one end of the replenishment developer flow means. This expresses the characteristic function of the part. That is, when the replenishment developer flow tube is fitted to the portion and can be fitted, and the state can be maintained, it is regarded as the fitting portion referred to here. Therefore, the replenishment developer flow tube is used to confirm the presence or absence of this characteristic, and may be a relatively elongated columnar or tubular object, and the replenishment developer constituting the replenishment developer replenishment system of the present invention. It is not limited to the agent flow means.

  If the replenishment developer storage member of the present invention is flexible and the replenishment developer storage member is flexible, it is introduced when the volume in the container main body is reduced as the replenishment developer is sucked. Occurrence of clogging of the replenishment developer due to local deformation at the time of volume reduction of the bag-like replenishment developer storage member is suppressed by the air. At the same time, the suction efficiency of the suction pump is increased, and the stored replenishment developer is discharged without remaining in the bag.

  Next, the auto refresh development method will be described.

  When the copying / printing operation is repeated, the toner in the developer accommodated in the developing tank 117 in the developing device of FIG. 1 is gradually consumed, and the ratio of the toner to the carrier, that is, the toner concentration is lowered. . This change in toner density is controlled by the above-described method so that the toner density always falls within the appropriate range necessary for development, and the replenishment developer is replenished.

  On the other hand, the carrier in the developer in the developing tank 117 is not consumed by the development, and is stirred together with the toner in the developing tank 117, the magnetic force of the magnet roll, and the electrostatic latent image carrier 1. The surface and the like are gradually contaminated and deteriorated due to the influence of contact with the surface. As the carrier deteriorates in this way, a predetermined charge amount cannot be imparted to the toner, resulting in a decrease in image quality. Therefore, it is necessary to replace the deteriorated carrier which is not consumed in the developing device with a new carrier. In FIG. 1, a replenishment developer composed of toner and a carrier is replenished using the above-described replenishment device as means for replenishing a new carrier into the developing device. The excess developer is discharged from the developer-side developer discharge port 60. By doing so, carrier deterioration can be prevented and a stable image can be obtained over a long period of time.

  Next, the carrier used for the replenishment developer and the two-component developer of the present invention will be described.

  The carrier of the present invention has a configuration that allows the present invention to be expressed in a volume-based 50% particle size (D50) of 15 to 70 μm, preferably 20 to 45 μm. If it is larger than 70 μm, it is insufficient to give the toner uniform and good charge, and it becomes difficult to faithfully reproduce the latent image, and it causes fogging and toner scattering.

  In addition, when the blow-type replenishment method (the above (2) and (3)) is used, the carrier settles and segregates in the container.

  Even when the suction-type replenishment method ((1), (3) described above) is used, the carrier is segregated in the replenishment developer feed flow path, and a stable amount of replenishment developer is obtained. Cannot be replenished.

  Further, when the particle size of the carrier is larger than 70 μm, the member included in the suction pump used as the air conveying means, particularly the rubber stator having low wear resistance, is easily worn, and the durability of the suction pump is increased. It may deteriorate or affect the transportability of the replenishment developer.

  On the other hand, when it is smaller than 15 μm, the carrier adheres to the electrostatic latent image carrier. Furthermore, since the transferability of the replenishment developer described later is increased, that is, the fluidity is deteriorated, it is difficult to stably transfer the replenishment developer.

  As described above, if the particle size is out of the above range, problems such as fogging and scattering are likely to occur even in the auto refresh development method, and stable image density and image quality are maintained over a long period of time. I can't.

  Further, as the carrier used in the present invention, the replenishment developer is supplied from the replenishment developer container or in the replenishment developer container in the replenishment apparatus having the replenishment method described in (1) to (3) above. When transported to the developing tank, the true specific gravity of the carrier is controlled for the purpose of improving carrier dispersibility in the replenishing developer and / or preventing carrier segregation. That is, the true specific gravity of the carrier used in the replenishment developer satisfies 2.5 to 4.2, preferably 3.0 to 4.0.

  According to said structure, since the true specific gravity of a carrier is 2.5-4.2, the specific gravity difference of a toner and a carrier is small, and the following problem can be solved.

  For example, when the true specific gravity exceeds 4.2, when the toner and the carrier are mixed, the carrier is difficult to uniformly disperse in the replenishment developer, or even if dispersed, the sieving / replenishment developer container is filled. Sometimes prone to segregation. Alternatively, even if the replenishment developer container is filled, if vibration is applied during transportation of the replenishment developer container, the carrier is likely to segregate in the replenishment developer container.

  Further, when the replenishment methods (1) to (3) of the present invention are used, fluidization of the replenishment developer is promoted by the air inflow means and the air conveyance means to the replenishment developer container. In addition, this makes it possible to more reliably replenish the developer tank with the replenishment developer from the viewpoint of preventing generation of agglomerates composed of toners and / or toner and carrier. On the other hand, in the case of a conventional carrier having a true specific gravity exceeding 4.2, since the specific gravity difference from the toner is large, the carrier settles and segregates in the container and in the replenishment developer flow tube, and the stable carrier concentration Cannot be replenished with the replenishment developer.

  Further, when a carrier having a specific gravity greater than 4.2 is used, the carrier tends to remain in the suction pump used as the air conveying means. For this reason, the members of the pump, particularly the rubber stator with low wear resistance, are easily worn by the carrier, which deteriorates the durability of the suction pump and affects the transportability of the replenishment developer. Sometimes.

  As a result, even with the auto-refresh development method, problems such as fogging and scattering are likely to occur, and stable image density and image quality cannot be maintained over a long period of time.

  When the true specific gravity is less than 2.5, it can be achieved by substantially reducing the content of the magnetic substance in the carrier, so that adhesion to the electrostatic latent image carrier is likely to occur.

  Since the carrier used in the present invention has an appropriate particle size and true specific gravity, when the developer for replenishment is mixed, sieved, and filled, the developer for replenishment is further transferred by the air conveying means. The stress on the toner carrier in the developer storage container and / or the replenishment developer feed channel / suction pump is very weak. For this reason, the surface property of the toner and the carrier and the external additive adhesion state of the toner are not deteriorated. Further, when the developer is made a predetermined layer thickness on the developing sleeve by the developer layer thickness regulating member (regulating blade), or when the developer is stirred in the developing device, the load applied to the developer is small. . For this reason, when the developer is used for a long period of time, the carrier and the toner are not easily deteriorated, so that the developing property such as fogging and toner scattering is hardly deteriorated, which is optimal for the auto-refresh development method.

  The replenishment developer of the present invention may adjust the particle size and specific gravity of the carrier as one means for arbitrarily controlling the transportability of the replenishment developer described below.

  The carrier used in the present invention may have a true specific gravity of 2.5 to 4.2, and there are no particular restrictions on the type and manufacturing method.

  Examples of carriers used in the present invention include surface oxidized or unoxidized iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth acidic metals, alloys thereof, oxides and ferrites thereof, and binder resins. A magnetic fine particle dispersed resin carrier composed of a metal oxide, a magnetic metal oxide or the like can be used.

  The carrier used in the present invention is preferably coated with a resin or a coupling agent in order to provide charging stability and environmental stability.

  As the carrier used in the present invention, a light metal-containing ferrite carrier and a magnetic fine particle dispersed resin carrier are suitably used for the following reasons. Ferrite particles that do not contain a light metal having a composition such as Cu—Zn and Ni—Zn, which are used in conventional development methods, have a true specific gravity of about 4.9. .2 or less is required. The light metal-containing ferrite carrier and the magnetic fine particle-dispersed resin carrier can be arbitrarily reduced in true specific gravity as compared with a ferrite carrier containing a heavy metal, and can be suitably used as the carrier of the present invention. In addition, the polymerized magnetic fine particle dispersed resin carrier containing non-magnetic metal oxide and magnetite can control the magnetic properties and specific gravity arbitrarily, has little shape distortion in the particles, can achieve a sharp particle size distribution, and particle strength It is relatively easy to make a high spherical shape, and is excellent in fluidity and transportability during replenishment. For this reason, segregation of the carrier of the replenishment developer including the carrier of the present invention hardly occurs, and it is preferable for further improving the discharge property from the replenishment developer container and the transportability by the pump means. In particular, the polymerized magnetic fine particle-dispersed resin carrier has a smaller porosity of the replenishment developer due to its shape and particle size distribution, so the capacity of the replenishment developer container can be reduced and the image forming apparatus can be easily downsized. .

  On the other hand, when the porosity decreases, the replenishment developer is in a state of being tightened when left for a long time in the replenishment developer container. In the present invention, the replenishment having the above-described methods (1) to (3) Since the apparatus is used, the replenishment developer at the time of replenishment has sufficient fluidity. Therefore, the polymerized magnetic fine particle dispersed resin carrier is suitable for the replenishing device of the present invention.

  Furthermore, since the magnetic fine particle-dispersed carrier contains magnetic fine particles dispersed in a resin, the hardness of the particles is softer than a ferrite carrier (including a light metal ferrite carrier). For this reason, it becomes difficult to wear the member which has in the suction pump used as an air conveyance means, especially the rubber stator with low wear resistance, and the durability of the suction pump can be improved, which is preferable.

  Further, since the particle size and resistance can be controlled over a wide range, it is particularly suitable for a high-speed copying machine or a high-speed laser beam printer in which the developing sleeve or the number of rotations of the magnet in the sleeve is large.

<Measurement method of true specific gravity of carrier>
The true specific gravity of the carrier in the present invention was measured according to JIS Z2504 using a true denser (manufactured by Seishin Enterprise).

<Measurement method of carrier particle size>
The volume average particle diameter (D50) of the carrier was measured using a laser diffraction particle size distribution measuring device (Hellos <HELOS>) under the conditions of a feed air pressure of 3 bar and a suction pressure of 0.1 bar.

  When measuring the carrier physical properties from the replenishment developer, the developer was washed with ion exchange water containing 1% of Contaminone N (manufactured by Wako Pure Chemical Industries, Ltd .: surfactant) to separate the toner and the carrier. Then, the above measurement is performed.

  As described above, iron powder, ferrite, and magnetite are used as the ferromagnetic material that can be suitably used in the present invention, and ferrite or magnetite is preferable. Even if the iron powder carrier is coated with a resin, the specific resistance of the core is low. Therefore, when an AC electric field is applied to the developing sleeve particularly suitable for the present invention, the charge of the electrostatic charge image leaks through the carrier and the static electricity is leaked. There are many cases where image defects are caused by disturbing the charge image, which is not preferable.

In the present invention, examples of the ferromagnetic material that can be suitably used for the carrier include metal compound particles such as magnetite and ferrite having magnetism represented by the following formula (1) or (2).
MO · Fe ₂ O ₃ (1)
M · Fe ₂ O ₄ (2)
(In the formula, M represents a trivalent, divalent or monovalent metal ion.)

  Examples of M include Be, Mg, Ca, Rb, Sr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Cd, Pb, and Li. It can be used alone or in plural.

  A light metal-containing ferrite carrier that can be suitably used in the present invention will be described. In the present invention, a light metal-containing ferrite carrier containing a light metal composed of Li, Be, Mg, K, Ca, Sr and Rb is particularly preferable. These are preferably used singly or in a plurality so that the true specific gravity can be easily controlled, but in combination with other metals such as Mn and K, the resin content for the surface coating treatment of the carrier described later is used. You may adjust it.

  Specific examples of the metal compound particles having magnetism include Ca—Mg—Fe ferrite, Li—Fe ferrite, Mn—Mg—Fe ferrite, Ca—Be—Fe ferrite, and Mn—Mg. Examples thereof include iron-based oxides such as -Sr-Fe-based ferrite, Li-Mg-Fe-based ferrite, and Li-Rb-Fe-based ferrite.

The ratio of the light metal to Fe ₂ O ₃ contained in the light metal-containing ferrite is 5:95 to 55:45, preferably 35:65 to 55:45, in mol%. When Fe ₂ O ₃ is less than this ratio, desired magnetization cannot be obtained, carrier adhesion to the electrostatic latent image carrier tends to occur, and image increase failure tends to occur. If the ratio is large, it is difficult to obtain a desired true specific gravity.

  Generally, a heavy metal-containing ferrite carrier has a large saturation magnetization, so that the magnetic brush becomes rigid. For this reason, the deterioration of the developer such as carrier spent or toner external additive deterioration tends to be large, and the magnetic brush may be textured on the toner image, which is not preferable.

  A well-known method can be employ | adopted for the manufacturing method of a ferrite particle. For example, the pulverized ferrite composition is mixed with a binder, water, a dispersant, an organic solvent, and the like, and particles are formed using a spray dryer method or a fluidized granulation method. Thereafter, firing in a rotary kiln or batch-type firing furnace at a temperature in the range of 700 to 1400 ° C., preferably 800 to 1200 ° C., followed by sieving and controlling the particle size distribution to obtain carrier core particles. Can be mentioned. Further, it is preferable to control the specific resistance of the core material particles by controlling the oxygen partial pressure in the firing stage or adding oxidation / reduction treatment to the surface of the particles after firing.

A small amount of other metal oxides may be added to the ferrite particles for the core material in order to control the degree of crystal growth on the particle surface, unevenness or particle density. The other metal oxides are one or more oxides belonging to groups IA, IIA, IIIA, IVA, VA, IIIB and VB of the periodic table, such as BaO, Al ₂ O ₃ , TiO ₂ , SiO _2. , SnO ₂ and Bi ₂ O ₅ .

  Further, conventionally known heavy metal oxides such as CuO and ZnO may be added as a charge accelerator. The amount of the other metal oxide added is preferably 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the ferrite component. When the addition amount is less than 0.01 parts by mass, crystal growth tends to be low, and the particle strength tends to be low. On the other hand, when the amount exceeds 10 parts by mass, the uniformity of the composition is lost, and the production of oxides other than the ferrite composition and the production of non-magnetic or weak magnetic materials due to the reaction between the oxide and hematite are likely to occur. As a result, there is a disadvantage that carrier adhesion to the photoreceptor occurs.

  Next, the magnetic fine particle dispersion type carrier most preferably used in the present invention will be described.

  As the metal compound particles used for the carrier core, the above-described metal compound particles having magnetism and the following nonmagnetic metal compound particles may be mixed and used.

Nonmagnetic metal compound particles include, for example, Al ₂ O ₃ , SiO ₂ , CaO, TiO ₂ , V ₂ O ₅ , CrO, MnO ₂ , α-Fe ₂ O ₃ , CoO, NiO, CuO, SnO, ZnO. , SrO, Y ₂ O ₃ and ZrO ₂ . In this case, one kind of metal compound particles can be used, but it is particularly preferable to use a mixture of at least two kinds of metal compound particles. In that case, it is more preferable to use particles having similar specific gravity and shape in order to increase the adhesion to the binder resin and the strength of the carrier core particles.

Specific examples of combinations include, for example, magnetite and hematite, magnetite and γ-Fe ₂ O ₃ , magnetite and SiO ₂ , magnetite and Al ₂ O ₃ , magnetite and TiO ₂ , magnetite and Ca—Mn—Fe ferrite, magnetite And Ca—MgFe ferrite can be preferably used. Among these, a combination of magnetite and hematite can be particularly preferably used.

  In the carrier core of the present invention, the content of the metal compound particles is preferably 80 to 95% by mass with respect to the magnetic fine particle dispersed carrier core.

  When the content of the metal compound particles is less than 80% by mass, the chargeability tends to be unstable, and the carrier is charged particularly in a low temperature and low humidity environment, and the residual charges are likely to remain. The additive easily adheres to the surface of the magnetic fine particle dispersed carrier particles. When the content of the metal compound particles exceeds 95% by mass, the strength of the magnetic fine particle dispersed carrier is lowered, and problems such as cracking of the magnetic fine particle dispersed carrier due to durability are likely to occur. Furthermore, it becomes difficult to obtain the true specific gravity, which is the greatest object for carrying out the present invention.

  The binder resin of the magnetic fine particle-dispersed carrier core particles used in the present invention is a thermosetting resin and is preferably a resin that is partly or wholly crosslinked three-dimensionally. As a result, the dispersed metal compound particles can be firmly bound, so that the strength of the magnetic fine particle dispersed carrier core can be increased, and the metal compound particles are not easily detached even in a large number of copies. The resin can be coated better.

  The method for obtaining the carrier core is not particularly limited to the method described below, but particles are produced by polymerizing the monomer from a solution in which the monomer and the solvent are uniformly dispersed or dissolved. And a method for producing the polymerization method. In particular, a method of obtaining a magnetic material-dispersed resin carrier core having a sharp particle size distribution and a small amount of fine powder by applying a lipophilic treatment to the metal oxide dispersed in the magnetic fine particle-dispersed carrier core particles is preferable. Used.

  In the present invention, in the case of a magnetic fine particle dispersed carrier used in combination with a small particle size toner having a weight average particle size of 3.0 to 10.0 μm in order to achieve high image quality, the carrier particle size is also the particle size of the toner. It is preferable to reduce the particle size according to the diameter. The above-described production method is particularly preferable because even if the carrier particle size is reduced, a carrier with less fine powder can be produced regardless of the average particle size.

As the monomer used for the binder resin of the carrier core particle, a radical polymerizable monomer can be used. For example styrene;
styrene derivatives such as o-methyl styrene, m-methyl styrene, p-methoxy styrene, p-ethyl styrene, p-tertiary butyl styrene;
Acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate Acrylate esters such as phenyl acrylate;
Methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate Methacrylic acid esters such as dimethylaminomethyl methacrylate, diethylaminoethyl methacrylate, benzyl methacrylate;
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate;
Acrylonitrile, methacrylonitrile, acrylamide;
Methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl ether, isobutyl ether, β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl ether, p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether, p -Vinyl ethers such as methoxyphenyl vinyl ether;
Mention may be made of diene compounds such as butadiene.

  These monomers can be used alone or in combination, and a suitable polymer composition can be selected so that preferable characteristics can be obtained.

  Other binder resin monomers for carrier core particles include bisphenols and epichlorohydrin as starting materials for epoxy resins; phenols and aldehydes of phenolic resins; urea and aldehydes of urea resins; melamine and aldehydes.

  The most preferred binder resin is a phenolic resin. Examples of the starting material include phenol compounds such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcil, and p-tert-butylphenol, and aldehyde compounds such as formalin, paraformaldehyde, and furfural. A combination of phenol and formalin is particularly preferable.

  When these phenol resins or melamine resins are used, a basic catalyst can be used as a curing catalyst. As the basic catalyst, various catalysts used in the production of ordinary resole resins can be used. Specific examples include amines such as aqueous ammonia, hexamethylenetetramine, diethyltriamine, and polyethyleneimine.

  In the present invention, the metal compound particles contained in the carrier core are preferably oleophilic in order to sharpen the particle size distribution of the carrier particles and to prevent the metal compound particles from being detached from the carrier. . When forming carrier core particles in which metal compound particles having been subjected to lipophilic treatment are dispersed, particles insolubilized in the solution are formed at the same time as the polymerization reaction proceeds from a solution in which the monomer and solvent are uniformly dispersed or dissolved. . At that time, it is considered that the metal oxide is taken in uniformly and at a high density inside the particles and has an effect of preventing aggregation of the particles and sharpening the particle size distribution.

  The oleophilic treatment is treated with an oleophilic agent which is an organic compound having one or more functional groups selected from epoxy groups, amino groups and mercapto groups, and a mixture thereof. Is preferred. In particular, an epoxy group is preferably used in order to easily achieve the range of the amount of adsorbed moisture of the present invention and to obtain a carrier having a stable charge imparting ability.

  The metal compound particles are preferably treated with a lipophilic treatment agent in an amount of 0.1 to 10 parts by weight, more preferably 0.2 to 6 parts by weight per 100 parts by weight of the metal compound particles. It is preferable in terms of enhancing the lipophilicity and hydrophobicity.

  The method of the present invention can be carried out by either a continuous method or a batch method, but usually a batch method is employed.

  The carrier used in the present invention is preferably coated with a resin or a coupling agent in order to provide charging stability and environmental stability.

The carrier in the present invention is obtained by coating the surface of the core material with a resin, and the resin is not particularly limited as long as it can be used as a matrix resin, and can be appropriately selected according to the purpose. For example, polyolefin resins such as polyethylene and polypropylene;
Polyvinyl resins and polyvinylidene resins such as polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone;
Vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight silicone resin comprising an organosiloxane bond or a modified product thereof;
Fluorine-based resins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene;
Examples include silicone resins; polyesters; polyurethanes; polycarbonates; phenol resins; urea-formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamide resins, and other amino resins; and epoxy resins. These may be used individually by 1 type and may use 2 or more types together.

  In the present invention, among these resins, it is preferable to use at least a fluororesin and / or a silicone resin. Use of a fluorine-based resin and / or a silicone resin as the resin is advantageous in that it has a high effect of preventing carrier contamination (impact) due to toner and external additives.

  Of these, silicone resins are preferably used from the viewpoint of adhesion to the core and prevention of spent. The silicone resin can be used alone, but is preferably used in combination with a coupling agent in order to increase the strength of the coating layer and control the charge to a preferable level. Furthermore, the aforementioned coupling agent is preferably used as a so-called primer agent, a part of which is treated on the surface of the carrier core before coating the resin, and the subsequent coating layer is accompanied by a covalent bond. It can be formed in a more adhesive state.

  Aminosilane is preferably used as the coupling agent. As a result, an amino group having positive chargeability can be introduced on the surface of the carrier, and the toner can be favorably imparted with negative charge characteristics. Furthermore, the presence of amino groups activates both the oleophilic treatment agent preferably treated with the metal compound and the silicone resin in the case of a magnetic material-dispersed resin carrier. For this reason, a stronger coating layer can be formed by further improving the adhesion of the silicone resin to the carrier core and simultaneously promoting the curing of the resin.

  Resin particles and / or conductive particles can be dispersed in the resin coating layer. Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among these, thermosetting resins that are relatively easy to increase the hardness are suitable, and in order to impart negative chargeability to the toner, it is preferable to use resin particles containing nitrogen atoms. These resin particles and conductive particles may be used alone or in combination of two or more.

  Examples of the conductive particles include metal particles such as gold, silver and copper, carbon black particles, semiconductive oxide particles such as titanium oxide and zinc oxide, titanium oxide, zinc oxide, barium sulfate, aluminum borate, and titanic acid. Particles whose surfaces such as potassium powder are covered with tin oxide, carbon black, metal or the like can be used. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular in the formation method of a resin coating layer. For example, a method of using a resin coating layer forming liquid that contains the resin particles such as crosslinkable resin particles and / or the conductive particles, and a styrene acrylic resin, fluorine resin, silicone resin, or the like as a matrix resin in a solvent. Is mentioned. Specifically, a dipping method in which the carrier core material is immersed in the resin coating layer forming liquid, a spray method in which the resin coating layer forming liquid is sprayed on the surface of the carrier core material, and a state in which the carrier core material is suspended by flowing air And a kneader coater method in which the solvent is removed by mixing with a resin coating layer forming solution.

  As one of means for controlling the transportability of the replenishment developer of the present invention, which will be described later, formation of a resin coating layer of a carrier, dispersion of resin particles and / or conductive particles in the resin coating layer, and adjustment of the surface state You may do it.

  Next, the toner used for the replenishment developer and the two-component developer of the present invention will be described.

  The toner according to the present invention comprises toner particles containing at least a binder resin and a colorant and an external additive. The toner according to the present invention has a weight average particle diameter of 3.0 to 10.0 μm, and preferably 4.5 to 8.5 μm.

  When the weight average particle diameter (D4) of the toner exceeds 10.0 μm, the toner for developing the electrostatic charge image becomes large, so that development faithful to the electrostatic charge image is difficult to be performed, and electrostatic transfer is not performed. If done, the toner will likely scatter. Further, when the weight average particle diameter of the toner is less than 3.0 μm, the dischargeability of the replenishment developer from the replenishment developer container tends to be lowered.

  Further, the toner particle size may be adjusted by using the transferability of the replenishment developer of the present invention, which will be described later, as one of the control means.

  An example of measuring the particle diameter of the toner is a method using a Coulter counter.

As the binder resin used for the toner particles, the following resins can be used. For example, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, or a substituted product thereof;
Styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethacrylic acid Acid methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene Styrene copolymers such as copolymers, styrene-acrylonitrile-indene copolymers;
Polyvinyl chloride; Phenol resin; Naturally modified phenolic resin; Natural resin modified maleic acid resin; Acrylic resin; Methacrylic resin; Polyvinyl acetate; Silicone resin; Polyester resin; Polyurethane resin; Butylal; terpene resin; coumarone indene resin; petroleum resin can be used.

  The styrenic polymer or styrenic copolymer may be cross-linked, or may be a mixed resin of a cross-linked resin and a non-cross-linked resin.

As the crosslinking agent for the binder resin, a compound having two or more polymerizable double bonds may be mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate;
And divinyl aniline, divinyl ether, divinyl sulfide, divinyl compounds such as divinyl sulfone; and compounds having three or more vinyl groups. These are used alone or as a mixture.

  The toner particles may contain a charge control agent.

Examples of substances that control toner particles to be negatively charged include the following substances. For example, organometallic compounds and chelate compounds are effective, and monoazo metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal compounds are preferably used. Furthermore, aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, their anhydrides, their esters, their phenol derivatives such as bisphenol;
Urea derivatives; metal-containing salicylic acid compounds; metal-containing naphthoic acid compounds; boron compounds; quaternary ammonium salts; calixarene; silicon compounds; styrene-acrylic acid copolymers; Acid copolymers; and nonmetal carboxylic acid compounds.

  Examples of the toner particles that are positively charged include the following substances. For example, amino compounds, quaternary ammonium compounds and organic dyes, particularly basic dyes and their salts are known, such as benzyldimethyl-hexadecyl ammonium chloride, decyl-trimethyl ammonium chloride, nigrosine base, nigrosine hydrochloride, safranine T and Crystal violet etc. are mentioned. These dyes can also be used as colorants.

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

  The toner particles may contain a magnetic material. Magnetic materials include iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel, or these metals and aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, And alloys with metals such as cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof. These magnetic materials may be colorants.

  As the colorant for the toner particles used in the present invention, a black colorant that is carbon black, a magnetic material, and that is toned in black using the following yellow / magenta / cyan colorant can be used.

  As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds, and the like are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168 or 180 is preferably used. Furthermore, C.I. I. You may use together dyes, such as solvent yellow 93,162,163.

  As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds, and the like are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221 or 254 is preferably used.

  As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably.

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

  Further, the toner particles according to the present invention preferably contain a wax, and the content thereof is preferably 1 to 20 parts by mass, more preferably 2 to 17 parts by mass with respect to 100 parts by mass of the binder resin. preferable.

  In the case of producing a toner by a pulverization method in which a mixture having a binder resin, a colorant and a wax is melt-kneaded, cooled, pulverized and classified to obtain toner particles, the amount of wax added is 100 parts by mass of the binder resin. 1 to 10 parts by mass is preferable. More preferably, it is 2-7 mass parts.

  When a toner is produced by a polymerization method in which toner particles are directly obtained by polymerizing a mixture containing a polymerizable monomer, a colorant and a wax, the amount of the wax added is the polymerizable monomer or the polymerizable monomer. 2-20 mass parts is preferable with respect to 100 mass parts of resin synthesize | combined by superposition | polymerization of a monomer. More preferably, it is 5-17 mass parts.

  Since the wax is usually less polar than the binder resin, the polymerization method in which the polymerization method is carried out in an aqueous medium tends to include a large amount of wax inside the toner particles. It can be used. Therefore, when the toner is manufactured by the polymerization method, a better offset prevention effect can be obtained.

  When the amount of the wax is less than the lower limit, the external additive, particularly titanium oxide, is easily liberated, and when it exceeds the upper limit, the external additive, particularly the silica toner, is used at a high temperature during the external additive treatment on the toner particles. The embedding in particles tends to be strong.

  In addition, the transfer amount of the replenishment developer of the present invention, which will be described later, may be used as one of control means to adjust the amount of wax on the toner particle surface.

  Next, a method for producing toner particles used in the present invention will be described. The toner particles used in the present invention can be produced using a known pulverization method and polymerization method.

  In the method for producing pulverized toner particles, binder resin, wax, pigment as colorant, dye or magnetic substance, charge control agent as required, and other additives are sufficiently mixed with a mixer such as a Henschel mixer or a ball mill. After mixing, the resulting mixture is melt-kneaded using a heat kneader such as a heating roll, kneader or extruder to disperse the metal compound, pigment, dye, and magnetic substance while the resin components are mutually compatible. Alternatively, the obtained kneaded product is cooled and solidified, and then pulverized and classified to obtain toner particles.

  Further, the toner particles may be spheroidized or modified using the transportability of the replenishment developer of the present invention as one of the control means.

  As a method for spheroidizing and modifying the toner particles, a method using a surface modifying device (JP 2004-326075 A, etc.), a method using hot air (JP 2000-29241 A, etc.), a mechanical impact force, and the like. It is possible to carry out using a known method such as the method according to JP-A-7-181732.

  A method for producing polymerized toner particles includes a method of obtaining spherical toner particles by atomizing a molten mixture into the air using a disk or a multi-fluid nozzle described in JP-B-56-13945, JP-B-36-10231, A method of directly producing toner particles using the suspension polymerization method described in JP-A-59-53856 and JP-A-59-61842, or a polymer that is soluble in a monomer Emulsion polymerization methods represented by dispersion polymerization methods that directly generate toner particles using water-insoluble organic solvents or soap-free polymerization methods that directly generate toner particles in the presence of a water-soluble polar polymerization initiator, After making the polar emulsion polymer particles, it is possible to produce toner particles using a hetero-aggregation method in which polar particles having opposite charges are added and associated.

  In addition, a so-called seed polymerization method in which a monomer is further adsorbed to the obtained polymerized toner particles and then polymerized using a polymerization initiator can be suitably used in the present invention.

  Furthermore, if necessary, the toner particles and the desired additive can be sufficiently mixed by a mixer such as a Henschel mixer to obtain the toner used in the present invention.

  Next, the external additive that is externally added to the toner particles will be described.

  External additives used in the present invention include inorganic fine powders such as silica, alumina and titanium oxide; fluidization of organic fine powders such as polytetrafluoroethylene, polyvinylidene fluoride, polymethyl methacrylate, polystyrene and silicone. It is preferable that an agent is externally added. By externally adding the fluidizing agent described above to the toner, fine powder exists between the toner and the carrier or between the toner particles. Therefore, it is suitable for imparting suitable fluidity to the toner. Further, the sieving property of the replenishment developer is also improved. Furthermore, the charge rising property, environmental stability, fluidity, transferability and the like of the developer are improved, and the life of the developer is also improved.

  The number average particle size of the fine powder described above is preferably 3 to 200 nm. When the average particle diameter exceeds 200 nm, the effect of improving fluidity is reduced, and the image quality may be deteriorated due to defects during development and transfer. If it is smaller than 3 nm, it becomes difficult to maintain fluidity during durability.

The surface area of these fluidizing imparting agents, specific surface area by nitrogen adsorption 30 m ² / g or more measured by a BET method, is good especially in the range of 50 to 400 m ² / g.

  It is preferable to add two or more kinds of these fluidizing agents, and the chargeability, environmental stability, fluidity of the toner obtained, fluidity (transportability) of the replenishment developer, and the like can be improved.

  When the toner is a negatively chargeable toner, it is preferable that at least one of the fluidization imparting agents described above is silica and the other is titanium oxide. That is, since silica has a higher negative chargeability than a fluidizing agent such as alumina or titanium oxide, it has high adhesion to the toner base and less free external additives. Therefore, filming on the electrostatic latent image carrier and contamination of the charging member can be suppressed. Further, the liberation of the external additive when the replenishment developer is passed through the sieve is small. On the other hand, the environmental characteristics of the toner are liable to deteriorate, and the charge amount of the toner under high humidity tends to decrease and the charge amount of the toner under low humidity tends to increase. Titanium oxide can make the charge rising property, prevention of charge-up, environmental stability, and uniform charge distribution. On the other hand, it tends to accumulate in the developing tank during long-term use and tends to cause a decrease in developer charging ability.

  Therefore, it is more preferable to use at least two kinds of silica and titanium oxide in combination because a synergistic effect in consideration of both characteristics can be obtained.

  The fluidizing agent is preferably hydrophobized in order to maintain chargeability under high humidity. An example of the hydrophobic treatment is shown below.

  A silane coupling agent is mentioned as one of the hydrophobizing agents, and the amount thereof is 1 to 40 parts by mass, preferably 2 to 35 parts by mass with respect to 100 parts by mass of silica. When the treatment amount is 1 to 40 parts by mass, moisture resistance is improved and aggregates are hardly generated.

  Another example of the hydrophobizing agent is silicone oil.

  Other external additives can be added for the purpose of imparting various toner characteristics. The external additive preferably has a particle size of 1/5 or less of the weight average particle size of the toner from the viewpoint of durability when added to the toner particles. As additives for the purpose of imparting these properties, for example, abrasives, lubricants, charge control particles and the like are used.

  Examples of the abrasive include metal oxides such as strontium titanate, cerium oxide, aluminum oxide, magnesium oxide and chromium oxide; nitrides such as silicon nitride; carbides of silicon carbide; and calcium sulfate, barium sulfate and calcium carbonate. The metal salt is mentioned.

  Examples of the lubricant include fluorine resin powders such as vinylidene fluoride and polytetrafluoroethylene; and fatty acid metal salts such as zinc stearate and calcium stearate.

  Examples of the charge controllable particles include metal oxides such as tin oxide, titanium oxide, zinc oxide, silicon oxide and aluminum oxide; and carbon black.

  These additives are preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner particles.

  Further, the transferability described later of the replenishment developer of the present invention may be used as a control means to adjust the external additive, the amount of additive added, the seed, and the state of adhesion to the toner particle surface.

  In the toner of the present invention, a small particle size external additive (“small particle size external additive”) and It is preferable to add a large particle size external additive (“large particle size external additive”).

  By adding such an external additive, the fluidity of the toner particle itself by the small particle size additive is improved and the adhesion between the toner particles by the large particle size additive is reduced. Thus, both of the so-called spacer effects can be reliably obtained. Therefore, a constant fluidity in the replenishment developer is maintained, agglomeration between toner particles and between toner and carrier particles is maintained, and the transportability in the replenishment developer is within a certain range. Can be controlled.

  The replenishment developer and the two-component developer used in the present invention have the above carrier and toner.

  Next, the replenishment developer and the two-component developer of the present invention will be described.

  When the two-component developer in the developing tank is prepared by mixing the toner and the carrier, the mixing ratio is 2 to 15% by mass, preferably 4 to 13% by mass as the toner concentration in the developer. Results. When the toner concentration is less than 2% by mass, the image density tends to be low. When the toner concentration exceeds 15% by mass, fogging or in-machine scattering is likely to occur, and the useful life of the developer tends to decrease.

  In the present invention, at least a toner and a carrier are mixed to prepare a replenishment developer. The ratio between the toner and the carrier is preferably adjusted at an arbitrary mixing ratio so that the transportability described below is within a certain range. Preferably, the mixing ratio of the toner and the toner is 1 to 30 parts by mass of the toner with respect to 1 part by mass of the carrier. Within this range, the charge imparting ability of the carrier in the developing tank can be stabilized efficiently. In the case of more than 30 parts by mass, even if the carrier of the present invention is used, the carrier, particularly the rubber stator with low wear resistance, is easily worn by the carrier. Become. As a result, the durability of the suction pump may deteriorate, or the transportability of the replenishment developer may be affected.

  The replenishment developer of the present invention has a transportability index of preferably 0.5 to 25.0, more preferably 1.0 to 20.0, and still more preferably 1.5 to 15.0.

  When the transportability index is less than 0.5, the fluidity is too high as a replenishment developer. For this reason, even when the replenishment device used in the present invention, that is, when the air is supplied to the replenishment developer storage container and / or when the replenishment developer is transferred by the air flow by the pump means, Even a carrier having a predetermined particle size and specific gravity may cause segregation of the carrier in the replenishment developer. Therefore, the replenishment developer may not be supplied to the developing tank at a stable carrier concentration (toner concentration) in the replenishment developer. As a result, even with the auto-refresh development method, problems such as inability to maintain a stable image density over a long period of time, fogging and scattering may easily occur.

  On the other hand, when the transportability index is greater than 25.0, the transportability of the replenishment developer is poor, so that a stable amount of the replenishment developer cannot be transported, that is, the replenishment amount according to the toner consumption amount is It can be difficult to control. In that case, even with the auto-refresh development method, there are cases where problems such as inability to maintain a stable image density over a long period of time, fogging and scattering are likely to occur. Further, when the transferability index is made larger than 25.0 by reducing the toner ratio of the replenishment developer, a member included in a suction pump used as an air conveying means, particularly a rubber made of low wear resistance. The stator is easily worn by the carrier. For this reason, the durability of the suction pump may deteriorate, or the transportability of the replenishment developer may be affected.

  Here, the “transportability index” is obtained by indexing the mobility of the developer for replenishment in a state where a constant vibration obtained by measuring with a parts feeder (manufactured by Konica Minolta) shown in FIG. 5 is given. Is. This indicates the ease with which the replenishment developer is transferred, that is, the ease with which the replenishment developer moves.

  This transportability index is different from the fluidity generally evaluated by, for example, the quietness density and the angle of repose when the replenishment developer is stationary.

  Specifically, as shown in FIG. 5, the parts feeder includes a drive source C for generating a specific vibration and a cylindrical ball D supported above the drive source C. A spiral slope E that connects the bottom surface and the upper end edge is formed along the inner peripheral wall surface of the ball D. Here, the slope E is disposed in such a manner that its upper end Ea protrudes radially outward from the side wall of the ball D at the same height position as the upper end edge of the ball D.

  In FIG. 5, F is a central axis of the ball D, G is a saucer provided below the upper end Ea of the slope E, and B is a weighing means connected to the saucer G.

  In this parts feeder, the rotational power supplied from the drive source C is transmitted to the ball D to convert it into a vibrating motion that vibrates the ball D as a whole, and the return position of the vertical motion is arranged at an angle. When the toner is changed by the action of the spring, the toner positioned in the ball D is transferred upward along the slope E and falls onto the tray G from the upper end Ea of the slope E.

Thus, in the measurement of the toner transportability index in the present invention, 1 g of the replenishing developer is introduced around the central shaft 6 inside the ball D, and the drive source C is set to a frequency of 134.0 to 136.0 Hz. The toner is driven under the condition of an amplitude of 0.59 to 0.61 mm, and the toner is moved upward along the slope E to reach the receiving tray G. The amount of toner reaching the receiving tray G measured by the measuring means 2 is The time from when the driving of the driving source C is started when it becomes 300 mg and 700 mg can be measured and calculated using the following general formula.
Transportability index = (700-300) mg / (T700-T300) sec

  In the above general formula, T300 indicates the time required to transfer 300 mg of toner to the tray G, and T700 indicates the time required to transfer 700 mg of toner to the tray G.

  The replenishment developer and the two-component developer of the present invention have the replenishment system of the replenishment system described in (1) to (3) above, and any system regardless of full color or monochrome adopting the auto refresh development system. But it can also be used. For example, it can be applied to a known development method such as a developer for a high-speed system, a developer for oilless fixing, a developer for cleanerless, or the like.

  Specific examples of the present invention will be described below, but the present invention is not limited to these examples.

<Example of Cyan Toner 1 Production>
To 710 parts by mass of ion-exchanged water, 450 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution was added and heated to 60 ° C., and then at 14000 rpm using a TK homomixer (made by Tokushu Kika Kogyo). Stir. To this, 68 parts by mass of 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium having a pH of 5.9 containing a calcium phosphate compound.

-Styrene 160 mass parts-n-butyl acrylate 36 mass parts-C.I. I. Pigment Blue 15: 3 5.0 parts by mass, aluminum di-t-butylsalicylate compound 2 parts by mass, 10 parts by mass of saturated polyester, ester wax (Mw: 500, Mn: 400, Mw / Mn: 1.25)
15 parts by mass The above material was heated to 60 ° C., and uniformly dissolved and dispersed at 13000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). In this, 10 g of polymerization initiators 2,2′-azobis (2,4-dimethylvaleronitrile) were dissolved to prepare a polymerizable monomer composition.

The polymerizable monomer composition was charged into the aqueous medium, and stirred at 10,000 rpm for 10 minutes in a Claire mixer (manufactured by MTechnic Co., Ltd.) at 65 ° C. and N ₂ atmosphere. Granulated. Thereafter, while stirring the aqueous medium with a paddle stirring blade, the temperature was raised to 80 ° C., and the polymerization reaction was carried out for 8 hours while maintaining the pH at 6.

  After completion of the polymerization reaction, the mixture was cooled, and hydrochloric acid was added to dissolve the calcium phosphate so as to have a pH of 1.5, followed by filtration, washing with water, drying, and classification to obtain toner particles having a weight average particle diameter of 6.5 μm. .

  The flowability improver shown in Table 1 was added to 100 parts by mass of the obtained toner particles and mixed with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain cyan toner 1. .

<Example of Cyan Toner 2 Production>
(Toner binder synthesis)
726 parts by mass of bisphenol A ethylene oxide 2-mole adduct, 274 parts by mass of isophthalic acid and 2 parts by mass of dibutyltin oxide were placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe. After reacting for 8 hours, the reaction was performed under reduced pressure of 10 to 15 mmHg for 5 hours. This was cooled to 160 ° C., 32 parts by mass of phthalic anhydride was added and reacted for 2 hours. Furthermore, this was cooled to 80 ° C. and reacted with 190 parts by mass of isophorone diisocyanate in ethyl acetate for 2 hours to obtain an isocyanate-containing prepolymer (1). Next, 278 parts by mass of this prepolymer (1) and 14 parts by mass of isophoronediamine were reacted at 50 ° C. for 2 hours to obtain a urea-modified polyester (1) having a weight average molecular weight of 63,500.

  In the same manner as above, 720 parts by mass of bisphenol A ethylene oxide 2-mole adduct and 280 parts by mass of terephthalic acid were subjected to polycondensation at 230 ° C. for 8 hours under normal pressure, and then reacted at a reduced pressure of 10 to 15 mmHg for 5 hours to obtain a peak molecular weight of 4900. A polyester (a) which was not modified was obtained.

  200 parts by mass of urea-modified polyester (1) and 800 parts by mass of unmodified polyester (a) are dissolved and mixed in 2000 parts by mass of an ethyl acetate / ethyl methyl ketone (MEK) (1/1) mixed solvent, and a toner binder ( An ethyl acetate / MEK solution of 1) was obtained. Part of the mixture was dried under reduced pressure to isolate toner binder (1). Tg was 62 ° C.

(Production of toner)
In a beaker, 240 parts by mass of the ethyl acetate / MEK solution of the toner binder (1), 20 parts by mass of pentaerythritol tetrabehenate (melting point: 81 ° C., melt viscosity: 25 cps), 5 parts by mass of cyan pigment (Pigment Blue 15: 3). Then, 2 parts by mass of an aluminum compound of ditertiary salicylic acid was added and stirred with a TK homomixer at 60 ° C. and 12000 rpm, and uniformly dissolved and dispersed. In a beaker, 706 parts by mass of ion-exchanged water, 294 parts by mass of hydroxyapatite 10% suspension (Superite 10 manufactured by Nippon Chemical Industry Co., Ltd.) and 0.2 parts by mass 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 stir bar and a thermometer, heated to 98 ° C. to remove the solvent, filtered, washed, dried, air-classified, and the weight average particle diameter was 6.5 μm. Toner particles were obtained.

  The fluidity improver shown in Table 1 was added to 100 parts by mass of the obtained toner particles, and mixed with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Koki Co., Ltd.) to obtain cyan toner 2. .

<Example of Cyan Toner 3 Production>
(Preparation of acidic polar group-containing polymerization resin)
Styrene monomer (St) 80 parts by weight butyl acrylate (BA) 20 parts by weight acrylic acid (AA) 5 parts by weight of monomer mixture 100 parts by weight Emulgen 950 (manufactured by Kao Corp.) 1 part by weight Neogen R (No. (Ichi Kogyo Seiyaku Co., Ltd.) 2 parts by weight of an aqueous solution mixture was added, and potassium persulfate was used as a catalyst for polymerization at 70 ° C. for 8 hours with stirring to obtain an acidic polar group-containing resin emulsion having a solid content of 50% .

(Toner preparation)
Acidic polar group-containing resin emulsion 200 parts by mass cyan pigment (Pigment Blue 15: 3) 5 parts by mass polyethylene wax dispersion 20 parts by mass (Chemical WF-640 manufactured by Mitsui Petrochemical Co., Ltd.)
Aluminum compound of ditertiary butylsalicylic acid 2 parts by mass Water 350 parts by mass The above mixture was heated to 25 ° C while stirring with a disper. The dispersion was then stirred for about 2 hours and then heated to 60 ° C., which was adjusted to pH 8.0 with ammonia. Further, when this dispersion was heated to 90 ° C. and kept at this temperature for 5 hours, particles having a weight average particle diameter of 6.5 μm were obtained. The particle dispersion was cooled, separated, washed with water, and dried. When this particle was observed with a scanning electron microscope, it was observed that it was composed of secondary particles of polymer particles and magnetic fine particles.

  The fluidity improver shown in Table 1 was added to 100 parts by mass of the obtained toner particles, and mixed with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain cyan toner 3. .

<Production example of cyan toners 4 and 5>
(Production example of polyester resin)
In a reaction vessel equipped with a thermometer, a stirrer, a condenser and a nitrogen introduction tube, 35 parts by mass of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2 ) -2,2-bis (4-hydroxyphenyl) propane 20 parts by mass, terephthalic acid 23 parts by mass, trimellitic anhydride 7 parts by mass, fumaric acid 15 parts by mass and 2-ethylhexanoic acid tin 0.02 parts by mass. Then, after replacing the inside of the reaction vessel with nitrogen gas, the temperature was gradually raised while stirring, and a condensation reaction was carried out at 215 ° C. for 4 hours to obtain a polyester resin. The Tg of the polyester resin was 58 ° C., the weight average molecular weight (Mw) was 65000, and the number average molecular weight (Mn) was 4500.

(Production of toner)
Toners 4 and 5 were prepared by the following method.

・ Hybrid resin 100 parts by weight ・ Wax (refined normal paraffin WAX maximum endothermic peak temperature in DSC 75 ° C.) 5 parts by weight ・ 1,4-di-t-butylsalicylic acid aluminum compound 2 parts by weight ・ Cyan pigment (Pigment Blue 15: 3) 5 parts by mass The above formulation was sufficiently premixed with a Henschel mixer. The obtained mixture was melt-kneaded with a twin-screw extruder, the melt-kneaded product was cooled, and the cooled product was coarsely pulverized to a particle size of about 1 to 2 mm using a hammer mill. Next, the coarsely pulverized product was finely pulverized to a particle size of 20 μm or less with an air jet type fine pulverizer. Thereafter, classification was performed using an air classifier (elbow jet classifier) to obtain toner particles having a weight average particle diameter of 6.5 μm.

  To 100 parts by mass of the obtained toner particles, a fluidity improver shown in Table 1 is added, and mixed with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.). Obtained.

Manufacturing carrier < Manufacturing carrier 1>
-Phenol 7.5 parts by mass-Formalin solution 11.25 parts by mass (formaldehyde about 40%, methanol about 10%, the rest is water)
・ 61 parts by mass of magnetite fine particles lipophilically treated with 1.0% by mass of γ-glycidoxypropyltrimethoxysilane (average particle size 0.24 μm, specific resistance 5 × 10 ⁵ Ω · cm)
・ 25 parts by mass of α-Fe ₂ O ₃ fine particles lipophilically treated with 1.0% by mass of γ-glycidoxypropyltrimethoxysilane (average particle size 0.60 μm, specific resistance 2 × 10 ⁹ Ω · cm)
The lipophilic treatment of magnetite and α-Fe ₂ O ₃ used here was 1.0 part by mass of γ-glycidoxypropyl with respect to 99 parts by mass of magnetite and 99 parts by mass of α-Fe ₂ O ₃ , respectively. Trimethoxysilane was added and premixed and stirred at 100 ° C. for 30 minutes in a Henschel mixer.

  The above materials and 11 parts by mass of water were mixed at 40 ° C. for 1 hour. To this slurry, 2.0 parts by mass of 28% by mass ammonia water as a basic catalyst and 11 parts by mass of water were placed in a flask, heated to 85 ° C. over 40 minutes with stirring and mixing, and reacted for 3 hours. A phenolic resin was produced and cured. Then, after cooling to 30 degreeC and adding 100 mass parts water, the supernatant liquid was removed, the deposit was washed with water, and air-dried. Next, this was dried at 180 ° C. under reduced pressure (5 mmHg or less) to obtain spherical composite particles containing magnetite fine particles using a phenol resin as a binder resin.

The obtained composite particles had a volume average of 50%: a particle size of 35 μm and a specific resistance of 2.2 × 10 ¹² Ω · cm.

  Thereafter, the surface of the composite particles was treated while continuously applying a shearing stress to 3% by mass of γ-aminopropyltrimethoxysilane A diluted with a toluene solvent. At that time, it was carried out while volatilizing the solvent at 40 ° C. and 100 torr under a dry nitrogen stream. Subsequently, a mixture of 0.5% by mass of straight silicone resin whose substituents are all methyl groups and 0.015% by mass of γ-aminopropyltrimethoxysilane B was coated with toluene as a solvent. At that time, it was carried out while volatilizing the solvent under a stream of dry nitrogen at 40 ° C. and 500 torr.

  Furthermore, this was baked at 170 degreeC, the coarse particle which aggregated was cut and adjusted with the sieve of 100 mesh.

  The carrier 1 was then conditioned at 20 ° C./60% RH for 100 hours in a hopper maintained at 23 ° C. and 60%. The physical properties of the obtained carrier 1 are shown in Table 2.

<Manufacture of carrier 2>
-150 parts by mass of a polyester resin composed of a derivative of terephthalic anhydride trimellitic anhydride / propylene oxide-added bisphenol A-500 parts by mass of magnetite used in Production Example 1-5 parts by mass of a quaternary ammonium salt compound The above materials are sufficiently premixed by a Henschel mixer. The mixture was melt-kneaded with a twin-screw extrusion kneader, cooled and coarsely pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized with an air jet fine pulverizer. Further, after classifying the obtained finely pulverized product, 0.02 μm styrene / methyl methacrylate copolymer resin particles were dry-coated with a hybridizer (manufactured by Nara Machinery Co., Ltd.) to obtain Carrier 2. The physical property values of Carrier 2 are shown in Table 2.

<Manufacture of carrier 3>
Mn—Mg—Sr ferrite particles 100 parts by mass (volume average particle size = 35 μm, true specific gravity = 4.5)
-Toluene 10 parts by weight-Polymethylmethacrylate resin (PMMA) 2 parts by weight PMMA resin is diluted with toluene, put into a vacuum degassing kneader together with Mn-Mg-Sr ferrite particles, stirred at 120 ° C for 30 minutes, and then decompressed. Then, toluene was removed and a film was formed on the surface of the ferrite particles to obtain a carrier 3. The physical property values of the obtained carrier 3 are shown in Table 2.

<Manufacture of carrier 4>
Mn—Mg—Fe ferrite particles: 100 parts by mass (volume average particle diameter = 35 μm, true specific gravity = 4.9), toluene: 10 parts by mass, polymethyl methacrylate resin (PMMA): 2 parts by mass, and PMMA resin Diluted with toluene, put into a vacuum degassing type kneader together with Mn-Mg-Sr ferrite particles, stirred for 30 minutes at 120 ° C, reduced pressure to remove toluene, and formed a film on the ferrite particle surface to form a carrier 4 was obtained. The physical property values of the obtained carrier 4 are shown in Table 2.

<Manufacture of carriers 5 to 7>
Carriers 5 to 7 were obtained in the same manner except that the ratio of the resin and magnetite was adjusted for the purpose of adjusting the true specific gravity in the production of the carrier 2. Table 2 shows the physical property values of the obtained carriers 5 to 7.

<Manufacture of carriers 8 to 10>
Carriers 8 to 10 were obtained in the same manner except for adjusting the stirring and mixing conditions and adjusting the D50 average particle diameter in the production of carrier 1. Table 2 shows the physical property values of the obtained carriers 8 to 10.

<Manufacture of carriers 11-13>
In the production of the magnetic carrier 2, carriers 11 to 13 were obtained in the same manner except that the pulverization and classification conditions were adjusted and the D50 average particle diameter was adjusted. Table 1 shows the physical property values of the obtained carriers 11 to 13.

[Example 1]
Using carrier 1 and cyan toner 1, a developer for replenishment was prepared by uniformly mixing using a V-type mixer so that the ratio of the toner to the total mass was 85% by mass.

  Further, using a carrier 1 and cyan toner, a two-component developer was prepared by uniformly mixing using a V-type mixer so that the ratio of the toner to the total mass was 8% by mass.

  Using the obtained replenishment developer and two-component developer, a commercially available copying machine CLC5000 (manufactured by Canon Inc.) adopts the auto-refresh development method, and the configuration of FIG. 1: replenishment development having an air pump and a mono pump Remodeled to an image forming device equipped with an agent replenishing device and a developing device, and produced 400,000 original images with an image duty of 5%. Regarding image density stability, image quality / image uniformity, image defects, fogging, and toner scattering Evaluation was performed.

  The air pump used in this embodiment for sending air to the replenishing developer container has a single unit performance of a maximum static pressure of 20 Kpa and a maximum flow rate of 2.0 L / Min. The replenishment developer storage container was made of polyethylene, and a sheet having a thickness of 100 μm was manufactured in a bag shape. The diameter of the replenishment developer feed tube 49-1 was 6 mm-length 10 cm, and the diameter of the replenishment developer feed tube 49-2 was 6 mm-length 10 cm.

  The results are shown in Table 3. Each measurement condition and evaluation criteria are shown below.

  The evaluation environment was performed under high temperature and high humidity (H / H: 32.5 ° C./90% RH). The paper used was a color laser copier SK paper manufactured by Canon Inc., which was conditioned for 24 hours under high temperature and high humidity (H / H: 32.5 ° C./90% RH).

[Stability of carrier concentration]
For every 500 sheets, the connecting portion between the developer supply pipe for replenishment (49-2 in FIG. 3) and the developing device P is removed, 5 g of the developer for replenishment is collected, and this is contaminated with N (surfactant). Was washed with ion-exchanged water containing 1% of toner, and the toner and carrier were separated, dried, and conditioned (25.0 ° C./60% RH) to measure the carrier concentration in the replenishment developer.

(Evaluation criteria)
A: When the maximum amplitude of carrier concentration is within ± 1% B: When the maximum amplitude of carrier concentration is greater than ± 1% and within ± 2% C: The maximum amplitude of carrier concentration is ± 2% When larger than ± 3% D: When the maximum amplitude of carrier concentration is larger than ± 3%

(Image density stability)
The image density is measured with a color reflection densitometer (for example, X-rite 504 AMANUFACTURED BY X-rite Co.). The image was evaluated every 100,000 sheets, and the worst image during evaluation was evaluated and judged as follows.
A: There is no density unevenness on the image, and the density is stable and good.
B: There is no density unevenness on the image, but there is a slight decrease in density.
C: There is a little density unevenness on the image, and there is a decrease in density.
D: Density unevenness and density reduction on the image are remarkable.

[Image uniformity / image quality]
Monochromatic solid images and halftone images were printed out, and the image uniformity and image quality were visually evaluated.
A: Very good (a level at which image unevenness cannot be confirmed with a uniform image)
B: Good (Slight image unevenness can be confirmed, but there is no practical problem at all)
C: Practical use possible (image unevenness can be confirmed, but practically possible level)
D: Not practical (level of image unevenness and practically difficult)

[Image defect]
Monochromatic solid image and halftone image are printed out, and the image defect (image defect due to blade clogging (streaky image unevenness etc.), image defect due to impurities, toner and / or carrier aggregates) (White spots and spots) were visually evaluated.
A: Very good (a level at which no image defect can be confirmed with a uniform image)
B: Good (Some image defects can be confirmed, but there is no problem in practical use)
C: Practical use possible (Image defects can be confirmed but practically possible)
D: Not practical (level of image defects and practically difficult)

[Fog]
For fog, a reflection densitometer (densitometer TC6MC: Tokyo Denshoku Technology Center) was used to measure the reflection density of blank paper and the reflection density of the non-image area of the paper imaged by the copying machine. The difference in reflection density between the two was shown based on the reflection density of white paper, and the worst fogging among the four colors was shown based on the following evaluation criteria.

(Evaluation criteria)
A: Less than 0.5% B: Less than 0.5-1.0% C: Less than 1.0-1.5% D: 2.0% or more

[Toner scattering]
Toner scattering was evaluated on the basis of the following evaluation criteria by observing the stain on the outer surface around the developing sleeve of the developer unit and the stain on the toner other than the developer unit after the endurance of 400,000 sheets.
A: Almost no recognition.
B: Some contamination is observed on the outer surface of the upstream toner scattering suppression mass portion of the developing device, but no contamination is observed on the outer surface of the downstream toner scattering suppression mass portion.
C: Stain is observed on the outer surface of the upstream toner scattering suppression mass portion and the outer surface of the downstream toner scattering prevention mass portion of the developing device, but no contamination is observed except for the developing device.
D: Dirt is recognized except for the developing container.

[Example 2]
Example 1 was performed in the same manner as Example 1 except that air was not supplied from the air pump to the replenishment developer container. The results are shown in Table 3. As the results show, good results were obtained, but all items were slightly inferior to Example 1. This is presumably due to the fact that the flowability of the replenishment developer was slightly worse than in Example 1 because no air was sent from the air pump to the replenishment developer container.

Example 3
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 2. FIG. The results are shown in Table 3. As the results show, good results were obtained.

Example 4
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 3. FIG. The results are shown in Table 3.

[Comparative Example 1]
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 4. FIG. The results are shown in Table 3. As the result showed, it deteriorated in all the evaluation items. This is because the specific gravity of the carrier is large, so that the carrier in the replenishment developer settles, segregates, and remains in the replenishment developer container, the replenishment developer feed pipe, and the suction pump. This is because it was not possible to replenish the replenishment developer having.

[Examples 5 and 6]
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 5 and the carrier 6, respectively. The results are shown in Table 3.

[Comparative Example 2]
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 7. FIG. The results are shown in Table 3. As the result shows, the image quality and image uniformity are remarkably deteriorated. This is presumed to be aggravated because the ratio of magnetite to the binder resin is reduced in order to reduce the specific gravity, the magnetization is weak, the adhesion to the electrostatic charge image carrier increases.

[Examples 7 and 8]
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 8 and the carrier 9, respectively. The results are shown in Table 3.

[Comparative Example 3]
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 10. FIG. The results are shown in Table 3. As the results show, the image density stability, image quality / image uniformity, etc. were significantly deteriorated. This is presumed to be aggravated because the particle size of the carrier is small, the magnetization becomes weak, the adhesion to the electrostatic charge image carrier increases. Further, it is presumed that because the transportability index is large, that is, the transportability of the replenishment developer is poor, stable replenishment cannot be performed.

[Examples 9 and 10]
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 11 and the carrier 12, respectively. The results are shown in Table 3.

[Comparative Example 4]
In Example 1, it replaced with the carrier 1 and carried out similarly to Example 1 except having used the carrier 13. FIG. The results are shown in Table 3. As the results show, the scattering, fogging, etc. were remarkably deteriorated. This is presumed that since the carrier has a large particle size, it is insufficient to uniformly and satisfactorily charge the toner, and scattering, fogging and the like are deteriorated. Furthermore, since the carrier particle size is large, the weight per carrier increases, so that the carrier in the replenishment developer in the replenishment developer container, the replenishment developer feed pipe, and the suction pump. This is presumed to be because the replenishment developer having a stable carrier concentration could not be replenished.

[Examples 11 to 13]
Example 1 was performed in the same manner as Example 1 except that the toner concentration of the replenishment developer was changed as shown in Table 3. The results are shown in Table 3. The results are shown in Table 3. As the results show, there was a tendency for each item to deteriorate slightly as the carrier concentration in the replenishment developer increased. This is presumably because the transportability index increased as the carrier concentration in the replenishment developer increased, and the replenishment developer could not be replenished smoothly and stably. This is presumably because the replenishment developer having the carrier concentration could not be replenished.

[Examples 14 to 16]
Example 1 was performed in the same manner as Example 1 except that the toner concentration of the replenishment developer was changed as shown in Table 3. The results are shown in Table 3. The results are shown in Table 3. As the results show, there was a tendency for each item to deteriorate slightly as the carrier concentration in the replenishment developer decreased. This is presumably because as the carrier concentration in the developer for replenishment becomes smaller, the deteriorated carrier and the fresh carrier are not easily replaced, and the effect of the auto-refresh development method cannot be obtained sufficiently.

[Examples 17 to 20]
Example 1 was performed in the same manner as Example 1 except that the toner concentration of the replenishment developer was changed as shown in Table 3. The results are shown in Table 3. The results are shown in Table 3.

It is explanatory drawing for demonstrating the structure of this invention. It is sectional drawing which shows an example of the developer storage container for replenishment used for this invention. 1 is a schematic diagram of a replenishment developer supply device of the present invention. FIG. 3 is an explanatory schematic view showing a MONO pump which is an example of a replenishment developer transfer unit of the present invention. It is a schematic diagram for explanation showing the configuration of a parts feeder for measuring the transportability of the replenishment developer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 3 Replenishment developer supply path 40 Replenishment developer storage container

Claims (16)

An air conveying means for supplying a developer for replenishment to the developing device of an image forming apparatus for developing an image by developing a latent image on the latent image carrier with powder toner, and connected to the air conveying means. A replenishment developer replenishment device provided with a replenishment developer storage container,
The replenishment developer comprises at least a toner and a carrier, and satisfies the following 1) and 2).
1) The volume-based 50% particle size (D50) of the carrier is 15 to 70 μm.
2) The true specific gravity of the carrier is 2.5 to 4.2.   A replenishment developer connected to the replenishment developer storage container and provided with air supply means for stably air-feeding the replenishment developer filled in the replenishment developer storage container The replenishment developer according to claim 1, wherein the replenishment developer is stored in the replenishment developer container of the replenishing device.   The developer for replenishment according to claim 1 or 2, wherein the true specific gravity of the carrier is 3.0 to 4.0.   The replenishment developer according to any one of claims 1 to 3, wherein the replenishment developer has a transportability index of 0.5 to 25.0.   The replenishment developer according to any one of claims 1 to 4, wherein the replenishment developer has a transportability index of 1.0 to 20.0.   The replenishment developer according to any one of claims 1 to 3, wherein the replenishment developer has a transportability index of 1.5 to 15.0.   The replenishment developer according to any one of claims 1 to 6, wherein the carrier is a magnetic fine particle-dispersed resin carrier formed of composite particles having at least magnetic fine particles and a binder resin.   The replenishment developer according to claim 7, wherein the composite particles are a magnetic fine particle dispersed resin carrier obtained by a polymerization method. An air conveying means for supplying a developer for replenishment to the developing device of an image forming apparatus for developing an image by developing a latent image on the latent image carrier with powder toner, and connected to the air conveying means. A replenishment developer replenishing device provided with a replenishment developer storage container provided,
The replenishment developer replenishing apparatus, wherein the replenishment developer comprises at least a toner and a carrier and satisfies the following 1) to 3).
1) The transferability index of the developer for replenishment is 0.5 to 25.0.
2) The volume-based 50% particle size (D50) of the carrier is 15 to 70 μm.
3) The true specific gravity of the carrier is 2.5 to 4.2.   A replenishment developer connected to the replenishment developer storage container and provided with air supply means for stably air-feeding the replenishment developer filled in the replenishment developer storage container The replenishment developer replenishment device according to claim 9, wherein the replenishment developer replenishment device is stored in the replenishment developer storage container of the replenishment device.   11. The developer replenishing device for replenishment according to claim 9 or 10, wherein the true specific gravity of the carrier is 3.0 to 4.0.   The replenishment developer replenishing device according to claim 9, wherein the replenishment developer has a transportability index of 0.5 to 25.0.   The replenishment developer replenishing device according to claim 9, wherein the replenishment developer has a transportability index of 1.0 to 20.0.   The replenishment developer replenishing apparatus according to claim 9, wherein the replenishment developer has a transportability index of 1.5 to 15.   15. The developer replenishing device according to claim 9, wherein the carrier is a magnetic fine particle dispersed resin carrier formed of composite particles having at least magnetic fine particles and a binder resin. .   The replenishment developer replenishing apparatus according to claim 15, wherein the composite particles are magnetic fine particle dispersed resin carriers obtained by a polymerization method.

Images