JP4377441B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device used for image formation by an electrostatic copying process such as a copying machine, a facsimile machine, and a printer, a process cartridge, and an image forming apparatus using these.

  In a conventional electrophotographic developing device, a developer such as toner is stirred and charged in a developing device housing, and then the developer is conveyed to a developer carrying member. The developer guided onto the developer carrier is regulated in the development area, which is a re-close area between the developer carrier and the latent image carrier, after the developer conveyance amount is regulated to be constant by the developer regulation member. Then, development is performed on the latent image carrier. At that time, the developer on the developer carrying member is ideally charged uniformly, but some of the developer is not sufficiently charged. Furthermore, frictional charging is performed between the developer, the developer carrier, and the supply member, and as a result, the supply member and the like tend to accumulate charges opposite to the toner. For this reason, the amount of charge per unit weight of the toner tends to be low due to frictional charging between the developer and the supply member. When these low-charge toners pass through the developer regulating member, they jump out of the developer carrying member and float in the apparatus, contaminating the main body and the recording paper. In particular, recently, resin is often used for the housing of the developing device, and when floating toner adheres to these resins, the amount of toner that repels the next floating toner and scatters in the machine increases. There is.

Further, as the charge amount of the developer decreases, the external additive externally added to the toner of the developer is likely to be liberated. When the released external additive is released to the outside of the developing apparatus and adheres to the image carrier, the particle size is very small and the adhesion is strong and hard, so the image is applied with the pressure of a cleaning member such as a blade. The toner is embedded on the surface of the carrier, and the toner adheres and grows from this as a starting point to become black stripes. The black stripes, is on the image appears turned white streaks in the solid portion, image quality is a problem that will have the drops.
Further, as the weakly charged developer increases, the developer having a reverse polarity and a low charged amount also tends to increase, and when these are conveyed to the development area by the developer carrier, There is a problem that background stains occur and the image quality deteriorates.

As a method for preventing the scattering and leakage of the developer with respect to these problems, conventionally, the edge of the developer carrier and the vicinity of the development region are covered with a case or a seal member as much as possible, and suction means or A method using a developer recovery member is known. For example, in Patent Document 1 and Patent Document 2, the developer seal member is brought into contact with the development sleeve below the development sleeve, and the width of the sliding contact portion between the development sleeve and the developer seal member is set to 2.0 mm or less. A developing device is disclosed that sets the distance from the inner wall of the lower part of the developing container to the developer seal member in the vicinity of the sliding contact portion. However, although the seal member can suppress the floating of the developer and toner from the developing device into the image forming apparatus main body, it cannot prevent the charge amount of the developer from being lowered.
In Patent Document 3, a space having a developing roller, a toner supply roller, and a developing blade in a developing device, a toner conveying member, and a toner container that stores toner is partitioned by a partition plate, and the developing roller and the toner supply roller And a developing device for reducing the volume of the space by providing a proximity member close to these members in the space having the developing blade. However, the seal member can suppress the floating of the developer and toner from the developing device into the image forming apparatus main body, but the effect is not sufficient.
Further, in Patent Document 4 and Patent Document 5, the power supply is at least one of the collection roller bias power supply so that the potential difference between the development roller and the collection roller in the adjacent region between the development roller and the collection roller is smaller than the discharge voltage according to Paschen's law. A developing device that controls driving is disclosed. However, these are also used as the developing bias of the developing roller, and there is a problem that a control mechanism is necessary and the control becomes complicated.

JP-A-6-83182 JP 2002-268380 A JP 2001-42640 A JP 2003-140451 A JP 11-119546 A

Accordingly, the present invention has been made in view of the above problems, and its object is to prevent the charge amount of the developer on the developer carrying member from decreasing with time, and to prevent the toner into the image forming apparatus. It is an object of the present invention to provide a developing device, a process cartridge, and an image forming apparatus using them, each including a simple member for preventing scattering.
In addition, the problem is that a developing device, a process cartridge, and the like including a simple member capable of suppressing the generation of a developer having a reverse polarity and obtaining a high-quality image by preventing a decrease in the charge amount of the developer. An image forming apparatus to be used is provided.

The features of the present invention, which is a means for solving the above problems, are listed below.
The developing device of the present invention includes a developer carrying member provided opposite to an image carrying member that forms a latent image, a supply unit that supplies the developer to the developer carrying member, and a developer amount on the developer carrying member. In the developing device, the developer is a non-magnetic one-component developer, and the supply means supplies the non-magnetic one-component developer in contact with the developer carrier. A metal plate disposed adjacent to the supply roller in the axial direction of the supply roller so as to face the supply roller and in contact with the developer layer on the supply roller. provided, to allow conduction to the axis of the supply means and the metal plate, and characterized by a between them at the same potential.
Further, the developing device of the present invention further includes an electric resistance between the shaft of the developer carrying member and the surface of the developer carrying member, an electric resistance between the shaft of the supplying unit and the surface of the supplying unit, and a shaft of the regulating unit. The electrical resistance between the surfaces of the regulating means is all 11 (LogΩ) or less.
The developing device of the present invention is further characterized in that the supply means has a surface formed of a conductive foam or brush.

Further, the developing device of the present invention is characterized in that the metal plate has a surface roughness Rz of a portion close to or in contact with the supply means that is 1/2 or less of a volume average particle diameter of the toner. .
In the developing device of the present invention, the metal plate further includes a seal member that abuts against the supply unit.
In the developing device of the present invention, the metal plate further includes a seal member that contacts the developer carrier.
Further, the developing device of the present invention is characterized in that the metal plate is connected to an electric circuit outside the developing device by a conductive material provided in a hole or a recess provided in the side wall of the developing device casing.
The developing device of the present invention is further characterized in that the metal plate is fixed to the upper wall of the developing device housing.

The process cartridge of the present invention integrally supports at least an image carrier that forms a latent image and a developing device that develops the latent image, and is detachable from the image forming apparatus. a developer carrying member provided opposite to the image bearing member to form a Ru comprises a supply means for supplying the developer to the developer carrying member, and a regulating means for regulating the amount of developer on the developer carrying member In the developing device, the developer is a non-magnetic one-component developer, and the supply unit is a supply roller that contacts the developer carrier and supplies the non-magnetic one-component developer, the device, over a feed roller axis direction so as to face the feed roller, and to be in contact with the developer layer on the feed roller, the metal plates are provided near the feed roller, the metal sheet And the supply And conductively axis stage, and the between them at the same potential, it characterized by using a developing apparatus.

An image forming apparatus according to the present invention includes an image carrier that forms a latent image, a charging device that uniformly charges the surface of the image carrier, and the surface of the charged image carrier is exposed based on image data to form a latent image. An exposure device for writing, a developing device for supplying toner to the latent image formed on the surface of the image carrier to make it visible, and a recording medium after transferring the visible image on the surface of the image carrier directly or to an intermediate transfer member In the image forming apparatus, the developing device forms a latent image. The image forming apparatus includes a transfer device that transfers the toner image, a cleaning device that cleans the image carrier or the intermediate transfer member, and a fixing device that fixes the toner image on the recording medium. a developer carrying member provided opposite to the image bearing member, a supply means for supplying the developer to the developer carrying member, a developing device Ru and a regulating means for regulating the amount of developer on the developer carrying member there are, the developer is non-magnetic one-component An image agent, said supply means, said developer carrying member is the feed roller for supplying the contact with the non-magnetic one-component developer, wherein the developing apparatus, the supply roller shaft so as to face the feed roller A metal plate is provided close to the supply roller so as to cross the direction and contact the developer layer on the supply roller , and the metal plate and the shaft of the supply means can be conducted, and between them the same potential, you being a developing device.
The image forming apparatus of the present invention further uses at least an image carrier that forms a latent image and a developing device that develops the latent image, and uses a process cartridge that is detachable from the image forming apparatus. It shall be the feature.

  According to the present invention, by the means for solving the above problems, even if the developing device in the image forming apparatus is used for image formation over a long period of time, the toner charge amount is prevented from being lowered, the image density is high, and there is no background stain. A quality image can be provided. In addition, by using this, it is possible to provide a process cartridge and an image forming apparatus that suppress toner scattering and do not cause internal contamination.

The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.
FIG. 1 is a schematic view showing the configuration of the developing device of the present invention. FIG. 2 is a schematic diagram showing a configuration of an image forming apparatus using the developing device of the present invention.
As shown in FIG. 1, a developing device of a one-component developing system using a non-magnetic one-component toner (hereinafter referred to as “toner”) as a developer is shown, but the developer and the developing device are limited to these. It is not a thing.
The developing device 5 includes a developing device housing 50 having an opening toward the photosensitive member 2, a developing roller 51 as a developer carrying member, a supply roller 52 that is a supply unit that supplies toner onto the developing roller 51, and development. Conveying paddle 57 that feeds the toner contained in the toner containing portion 56 in the apparatus housing 50 to the supply roller 52 side, and contacts the developing roller 51 to regulate the layer thickness of the toner carried on the developing roller 51. A regulating roller 53 is provided as a developer layer regulating means for forming a toner layer having a predetermined layer thickness.

The developing roller 51 is partly exposed from the opening of the developing device casing 50 and is installed so as to be rotatable counterclockwise as indicated by an arrow at a predetermined linear speed during development, and carries toner on the surface of the developing roller 51. It is transported to a development position that is a contact portion with the photoconductor 2 and a latent image formed on the photoconductor 2 is developed. The supply roller 52 is in contact with the developing roller 51 with a predetermined pressure. The developing roller 51 uses a metal shaft as a support portion.
The supply roller 52 is in contact with the developing roller 51 so that the amount of toner supplied to the developing roller 51 is regulated. Further, the transport paddle 57 is installed so as to be rotatable in the counterclockwise direction of the arrow, and the toner is sent to the supply roller 52 side by this rotation. As the material of each conveyance paddle, for example, a material having soft elasticity such as polypropylene can be used, and the elasticity is used to rotate the toner in close contact with the inner wall of the developing device casing 50 to reliably convey the toner. To do. The supply roller 51 uses a metal shaft as a support portion.
The regulating roller 53 regulates the toner on the developing roller 51 to a predetermined layer thickness and frictionally charges the toner by slidingly contacting the toner. The toner charged on the developing roller 51 develops the electrostatic latent image on the photoreceptor 2. The restriction roller 53 uses a metal shaft as a support portion. Here, the regulating member that regulates the amount of developer conveyed onto the developing roller 51 may be a blade. The blade is made of an elastomer such as urethane resin or fluorine resin. As a result, the amount of developer conveyed can be regulated without imposing an excessive load on the developer.

Here, as the material of the surface portion of the regulating roller 53, a fluororesin and a corn resin coating are used. Further, a scraper 53 a is in contact with the restriction roller 53, and scrapes off the toner on the surface of the restriction roller 53 that has passed through the contact portion with the developing roller 51. A spring (not shown) is provided as an urging unit for the developing roller 51 and the regulating roller 53 due to environmental fluctuations such as humidity, and presses the regulating roller 53 against the developing roller 51.
Further, in order to prevent toner from leaking from the gap between the developing roller 51 and the developing device casing 50, the inner surface of the developing device casing 50 has an inlet seal extending so that the tip abuts against the surface of the developing roller 51. Seals 55a and 55b as members are provided.

Further, a metal plate 54 that is close to or in contact with the developing roller 51 and the supply roller 52 is provided in the developing device casing 50. As shown in FIG. 1, the supply roller 52 is abutted here. Further, it is conducted to at least one of the developing roller 51, the supply roller 52, and the regulating roller 53, and a potential difference of 400 V or less is maintained. FIG. 3 is a diagram schematically illustrating a conductive state between the metal plate and the developing roller, the supply roller, and the regulating roller.
Developing roller 51 and the supply roller 52, and friction of the toner with the pressing to Turkey between the regulating roller 53, and charges the toner. In this charging, for example, if the toner is negatively charged, positive charge remains on the developing roller 51, the supply roller 52, and the regulating roller 53. Conventionally, in a developing device not provided with the metal plate 54, the positive charge is accumulated, thereby inhibiting the frictional charge with the toner, and the negative charge of the toner becomes insufficient. Even a polar toner or a negatively charged toner with a small charge amount increases. Since the weakly charged toner also has a small mirror image force with the developing roller 51, toner that is released from the rotating developing roller 51 and floats is generated, and the inside of the image forming apparatus 1 is soiled. Further, the reversely charged toner is developed on the background portion, thereby causing background staining.

Therefore, here, as shown in FIGS. 2 and 3, the metal plate 54 is brought into contact with the supply roller 52 so that the positive charge accumulated in the supply roller 52 is released through the metal plate 54. At this time, in the electrically floating state, no electric charge flows, but by making it conductive, the accumulated positive electric charge can flow from the supply roller 52 to the ground. As a result, the supply roller 52 is always at an electric potential of 0, and the toner can be negatively charged by frictional charging with the toner. Further, the potential between 400 V and below is maintained between the metal plate 54 and the supply roller 52 and the like. By providing this potential difference, it is possible to maintain a stable state at an early stage as a driving force for charges accumulated in the metal plate 54 and the supply roller 52 and the like. This potential difference is within a range in which the developing roller 51 and the metal plate 54 adjacent thereto do not generate Paschen's law discharge. However, even if the atmosphere, temperature and humidity in the image forming apparatus 1 change, the potential difference is also present in the image forming apparatus 1. Even if dirt is floating, it is set to 400 V or less as a range not to be discharged. In the developing device of the present invention, even if the metal plate 54 is provided in the developing device, the charge due to frictional charging with the toner is not accumulated in the developing roller 51 or the like within a range where no discharge occurs. As a result, the charge amount of the toner can be prevented from decreasing over a long period of time, and the toner can be prevented from scattering in the image forming apparatus 1, thereby obtaining a high-quality image.
At this time, it is preferable that the regulating roller 53 that regulates the layer thickness of the developing roller 51 is also conducted. The regulating roller 53 is also frictionally charged because it is in contact with the toner, and when charge of reverse polarity is accumulated, the toner transported to the transport area is charged with reverse polarity or negatively charged toner. May not be conveyed due to the repulsive force, and the layer thickness on the developing roller 51 may decrease. By keeping the regulating roller 53 conductive, it is possible to prevent the accumulation of charges having a reverse polarity. Even if a blade-shaped elastomer is used as the regulating member, if the support member is conductive, accumulation of electrification generated on the blade can be similarly suppressed.

Further, the metal plate 54 may be provided close to the supply roller 52 and the developing roller 51. By providing the metal plates 54 close to each other, the toner conveyed between the supply rollers 52 and the like can be frictionally charged without applying excessive pressure to the toner to be crushed or fused. As a result, the toner charge amount can be prevented from being lowered, and a high-quality image can be obtained over a long period of time.
Further, in the developing device 5 of the present invention, between the metal plate 54 and the supporting portion for the developing roller 51, the supporting portion for the supply roller 52, and the supporting portion for at least one roller selected from the supporting portions for the regulating roller 53. To eliminate the potential difference and make it the same potential. The frictional charging with the toner is performed on the surface of the developing roller 51 and the like, but by making the shaft of the developing roller 51 and the like have the same potential, it is possible to prevent the electric charge from being unevenly distributed. At this time, the electrical resistance between the surface of each roller and each shaft is set to 11 (LogΩ) or less. When the electrical resistance increases, the electrical capacitance component increases. For example, charges accumulate between the surface of the developing roller 51 and the shaft of the developing roller 51 and do not flow to the ground and do not attenuate. For this reason, the charge amount of the toner is slightly reduced by long-term use. In order to prevent this decrease, the electric resistance is set to 11 LogΩ or less.
The electrical resistance between the surfaces of the rollers 51, 52, 53 and the shafts of the rollers 51, 52, 53 is performed as follows. First, a roller is placed on a horizontally placed metal flat plate, and an ammeter is applied while applying a voltage of 100 V between the metal flat plate and the roller shaft while applying a load of 100 g to both ends of the roller shaft. Measure the current value and calculate the electrical resistance.

In this developing device 5, the developing roller 51 has a surface made of metal such as aluminum or SUS, or urea resin, melamine resin, urethane resin, silicone resin, fluorine resin, phenol resin, polyamide resin, epoxy resin on these metal bases. And a polyester resin, and the like, but a surface composed of a conductive resin in which a conductive material is dispersed in a melamine resin, a urethane resin, or the like is provided. As the conductive material, carbon black, copper powder, aluminum powder metal powder, zirconium solid solution, solid solution containing F such as fluorite, and ionic conductor such as alkali metal salt such as aluminum can be used. Thereby, the electrical resistance of the surface layer is set to 11 (LogΩ) or less. This surface is 4 μm or less in Rz. Preferably it is 2 μm or more. When Rz is small, the amount of toner on the developing roller 51 is reduced, and when Rz is large, the uniformity of the toner layer is impaired and unevenness in image density occurs.
Feed roller 52 is provided with a surface which consists of a metal cored bar and urethane resins, silicone resins, the resin that by the conductive resin obtained by dispersing a conductive material originating foam or fibrous, such as EPDM resin brush. The above-described material is used as the conductive material. Thereby, the electrical resistance of the surface layer is set to 11 (LogΩ) or less.
The regulation roller 53 uses a conductive resin in which a conductive material is dispersed in a resin such as a fluororesin or a silicone resin, which is a resin having a small friction coefficient. The above-described material is used as the conductive material. Thereby, the electrical resistance of the surface layer is set to 11 (LogΩ) or less. If the surface roughness is too rough, the toner layer will be uneven. Therefore, the roughness should be 4 μm or less for a general image, and in the case of a high definition (600 dpi or more) image, Rz The hardness is preferably 2 μm or less, and the hardness is s-standard of JIS- K 6253, and a range of 50 ° to 85 ° may be selected.

Further, in the developing device 5, in order to obtain a high-definition image, it is preferable to use toner having a volume average particle diameter of 3 to 10 μm. The use of small-diameter toner has the advantages of increasing the image resolution and increasing the toner charge amount, thereby increasing the margin for preventing scumming and improving the gradation reproducibility. On the other hand, the developing roller 51, the supply roller 52, The toner easily leaks from the regulation roller 53. By providing the seal member 55 on these rollers, a stable toner layer can be formed without causing toner leakage even when toner having a small particle diameter is used.
The metal plate 54 is made of a metal such as aluminum, soft iron, or SUS. At this time, the surface roughness Rz of the metal plate 54 is set to ½ or less of the volume average particle diameter of the toner. This is because when the surface roughness exceeds 1/2, the floating toner is easily adsorbed, and once adsorbed, it is difficult to separate. In particular, when it is in contact with the supply roller 52 and the developing roller 51, it is difficult to detach, so when it continues to receive pressure, it will be deformed and fused. When this occurs on the entire metal plate 54, the state is the same as when an insulating film is provided on the surface of the metal plate 54. Even when the supply roller 52 and the metal plate 54 are electrically connected, the charge generated by frictional charging with the toner on the supply roller 52 or the like does not flow and accumulates, so the charge amount of the toner gradually decreases. Toner scattering and background smudges.

FIG. 4 is a diagram schematically showing a conductive state between a metal plate and a developing roller, a supply roller, and a regulating roller in another embodiment of the developing device of the present invention. It is the figure which added the metal plate of the part contact | abutted to a supply roller, (b) is the figure which provided the metal plate in the downward direction rather than the upper direction of a supply roller. As shown in FIG. 4A, the second metal plate 54a to which the portion in contact with the supply roller 52 is added may be finished to a surface roughness Rz that is ½ or less of the volume average particle diameter of the toner. . Further, as shown in FIG. 4B, the added second metal plate 54 a may be provided below the supply roller 52.
FIG. 5 is a configuration diagram showing a state in which the metal plate used in the developing device of the present invention is electrically connected to the outside of the developing device. The metal plate 54 can be connected to an electric circuit outside the developing device 5 by providing a hole or a recess in the side wall of the developing device housing 50. A protruding portion 54b may be provided on the metal plate 54 in accordance with the hole or the concave portion and connected to the outside, or a conductive material may be connected to the metal plate 54 from the outside. Thereby, it can be easily connected to the outside. Parts can be simplified to facilitate assembly. Further, the metal plate 54 is fixed to the upper wall of the developing device housing 50 made of resin. Since a high voltage such as a developing bias is applied to the developing device casing 50, the developing device casing 50 is often made of resin in order to prevent current from leaking, so that it functions as a reinforcing material that reinforces this strength. be able to. Fixing may be carried out by screwing or pasting with a double-sided tape.

  The image forming apparatus 1 of the present invention will be described with reference to FIG. Here, the color image forming apparatus 1 uses a belt system for the photosensitive member 2 and the intermediate transfer member. The photoconductor 2 rotates in the direction of the arrow in the figure, and is stretched around a drive roller 21 and driven rollers 22 and 23. Around the photoconductor 2, a photoconductor cleaning unit 7 and a charging unit 3 as a charging unit. Further, an exposure unit 4, a transfer device 6 having an intermediate transfer belt 61, a reflection density sensor as a density detection unit (not shown), and the like are arranged. The developing means 5 as a toner image forming means is composed of four developing devices, a yellow developing device 50Y, a magenta developing device 50M, a cyan developing device 50C, and a black developing device 50K.

The specifications of the developing device are as follows.
(Development roller)
Developing roller diameter: Φ26mm
Developing roller surface material: polyester melamine resin + carbon black Developing roller surface layer electric resistance: 5 (LogΩ)
Developing roller surface roughness: 2.6 μm (Rz)
(Supply roller)
Roller outer diameter: Φ16mm
Roller material: polyurethane foam + tin oxide Roller electrical resistance: 5 (LogΩ)
Biting amount (vs. developing roller): 0.5 mm
(Regulation roller)
Roller outer diameter: Φ14mm
Roller surface material: Fluorine resin + carbon black Roller electrical resistance: 5 (LogΩ)
Roller hardness: 75 ° (JIS K6253)
Roller surface roughness: 2.6 μm (Rz)

(Metal plate)
Metal plate material: soft iron Added second metal plate: SUS304
Surface roughness: 2.6 μm (Rz)
(toner)
Low molecular weight polyester resin 100 parts by weight Carbon black 6 parts by weight Polymer charge control agent 1 part by weight These are kneaded by an ordinary screw kneader kneading method, and then the coarsely pulverized toner after rolling and cooling is pulverized by a jet mill. In addition, a toner having a volume average particle size of 6.7 μm and a number average particle size of 6.1 μm was obtained using an airflow classifier. Similarly, for magenta, cyan and yellow, color toners were obtained by replacing the pigments.
Next, 0.3 parts by weight of silica was added to 100 parts by weight of each color toner thus obtained and mixed for 1 minute with a Henschel mixer. Subsequently, 0.3 part by weight of titania was added and mixed for 1 minute, and 1.0 part by weight of silica was further added and mixed for 1 minute. The average toner charge amount on the developing roller is 30 μC / g.
(Photoconductor)
Black solid part potential (VL): -50 (V) (average)
Background potential (Vd): -500 (V) (average)

Here, FIG. 6 is a diagram showing a circuit for measuring a current value flowing through the metal plate. FIG. 7 is a diagram illustrating a measurement result of the current flowing through the metal plate.
As shown in FIG. 6, an electric circuit was formed by setting the metal plate, the developing roller 51, the supply roller, and the regulating roller 53 to the same potential, and the current value flowing through the metal plate was measured. At this time, the metal plate is connected, the supply roller and the metal plate are set to the same potential, and the result of FIG. 7 showing the value of the current flowing to the ground shows that a current having a polarity opposite to that of the toner flows. Further, at this time, it can be seen that no current flows from the supply roller from the result of FIG. 7 showing the value of the current flowing to the ground with the metal plate in the float state. In this state, it can be seen that charges having a polarity opposite to that of the charged toner are accumulated in the supply roller.

When forming a full-color image, a visible image is formed in the order of the yellow developing device 50Y, the magenta developing device 50M, the cyan developing device 50C, and the black developing device 50K. , Referred to as “primary transfer”), a full-color image is formed. The intermediate transfer belt 61 is stretched by a drive roller, a primary transfer roller 62, and a driven roller, and is driven by a drive motor (not shown). By providing a belt position detection mark at the end of the intermediate transfer belt 61 and thereby starting the image forming process for each color, it is possible to accurately overlay each color image. The secondary transfer unit as a secondary transfer unit includes a secondary transfer roller 63 and a contact / separation mechanism (not shown) that contacts and separates the secondary transfer roller 63 from the intermediate transfer belt 61. Secondary transfer is performed by contacting a back surface of a transfer material as an image carrier and applying a bias. The secondary transfer roller 63 is configured by coating an elastic body such as urethane adjusted to a resistance value of 10 ⁵ to 10 ¹⁰ Ω with a conductive material on a metal core such as SUS. You may use it as it is, and you may coat | cover the surface with high releasability films, such as a fluororesin, as needed. The transfer material is fed by the paper feed roller 45 and the registration roller 44 at the timing when the leading end of the four-color superimposed image on the surface of the intermediate transfer belt 61 reaches the secondary transfer position. The secondary transfer roller 63 is usually separated from the surface of the intermediate transfer belt 61. However, the secondary transfer roller 63 is pressed at a timing when the four-color superimposed image formed on the surface of the intermediate transfer belt 61 is collectively transferred to the transfer material, and the high pressure Transfer to a transfer material is performed by applying a predetermined bias voltage by a power source. The four-color superimposed image transferred to the transfer material is fixed by the fixing device 8 and then discharged. The toner transferred from the secondary transfer roller 63 to the intermediate transfer belt 61 is collected from the intermediate transfer belt 61 by the belt cleaning unit.

  At this time, in the image forming apparatus 1 in which the metal plate is brought into contact with the supply roller 52 and set to the same potential, the background stain and the image density are reduced as compared with the image forming apparatus 1 in which the metal plate is not provided. In addition, toner scattering in the image forming apparatus 1 was improved.

  Furthermore, at least the photosensitive member 2 and the supply roller 52 that form a latent image integrally support the developing roller 51, the regulating roller 53, and a developing device in which a metal plate is connected, and can be attached to and detached from the main body of the image forming apparatus 1. Process cartridge. As a result, it is possible to prevent the developer in the process cartridge from scattering into the image forming apparatus 1 and to suppress a decrease in the toner charge amount and obtain a high-quality image. It is only necessary to replace the process cartridge, which improves convenience.

1 is a schematic diagram illustrating a configuration of a developing device of the present invention. 1 is a schematic diagram illustrating a configuration of an image forming apparatus using a developing device of the present invention. FIG. 5 is a diagram schematically showing a conductive state between a metal plate and a developing roller, a supply roller, and a regulating roller. FIG. 9 is a diagram schematically showing a conductive state between a metal plate and a developing roller, a supply roller, and a regulation roller in another embodiment of the present invention, and (a) is a portion of the metal plate that contacts the supply roller. (B) is a view in which a metal plate is provided below the supply roller, not above. FIG. 3 is a configuration diagram showing a state in which a metal plate used in the developing device of the present invention is electrically connected to the outside of the developing device. It is the figure which showed the circuit which measures the electric current value which flows into a metal plate. It is a figure which shows the measurement result of the electric current which flowed through the metal plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Photoconductor 3 Charging apparatus 4 Exposure apparatus 5 Developing apparatus 50 Developing apparatus housing | casing 51 Developing roller 52 Supply roller 53 Control roller 53a Scraper 54 Metal plate 54a Added 2nd metal plate 54b Protruding part 55 Sealing member 56 Toner storage unit 57 Conveying paddle 58 Constant voltage power supply 6 Transfer device 61 Intermediate transfer belt 62 Primary transfer roller 63 Secondary transfer roller 7 Photoconductor cleaning device 8 Fixing device 40 Paper feed cassette 41 Manual tray 42 Conveying roller pair

Claims (11)

A developer carrier provided opposite to the image carrier that forms the latent image, a supply unit that supplies the developer to the developer carrier, and a regulation unit that regulates the amount of the developer on the developer carrier. In the developing device provided,
The developer is a non-magnetic one-component developer,
The supply means is a supply roller that contacts the developer carrier and supplies a non-magnetic one-component developer;
In the developing device , a metal plate is provided close to the supply roller so as to face the supply roller in the axial direction of the supply roller and in contact with the developer layer on the supply roller .
Developing apparatus is characterized in that a conductively an axis of said supply means and said metal plate, and that between them the same potential. The developing device according to claim 1,
The developing device includes an electrical resistance between a support portion of the developer carrier and a surface of the developer carrier, an electrical resistance between the support portion of the supply means and the surface of the supply means, and a support portion and a restriction of the regulation means. The developing device characterized in that the electrical resistance between the surface of the means is 11 (LogΩ) or less. The developing device according to claim 1 or 2,
The developing device, wherein the supply means has a surface formed of a conductive foam or brush. In the developing device according to any one of claims 1 to 3,
The developing device according to claim 1, wherein the metal plate has a surface roughness Rz of a portion close to or in contact with the supply unit that is 1/2 or less of a volume average particle diameter of the toner. The developing device according to any one of claims 1 to 4,
The developing device according to claim 1, wherein the metal plate includes a seal member that abuts on the supply unit. The developing device according to any one of claims 1 to 5,
The developing device according to claim 1, wherein the metal plate includes a seal member that contacts the developer carrier. The developing device according to any one of claims 1 to 6,
The developing device, wherein the metal plate is connected to an electric circuit outside the developing device by a conductive material provided in a hole or a recess provided in a side wall of the developing device casing. The developing device according to any one of claims 1 to 7,
The developing device, wherein the metal plate is fixed to an upper wall of the developing device casing. At least a process cartridge that integrally supports an image carrier that forms a latent image and a developing device that develops the latent image, and is detachable from the image forming apparatus.
The process cartridge is
A developer carrier provided opposite to the image carrier that forms the latent image, a supply unit that supplies the developer to the developer carrier, and a regulation unit that regulates the amount of the developer on the developer carrier. a developing device Ru comprising,
The developer is a non-magnetic one-component developer,
The supply means is a supply roller that contacts the developer carrier and supplies a non-magnetic one-component developer;
In the developing device , a metal plate is provided close to the supply roller so as to face the supply roller in the axial direction of the supply roller and in contact with the developer layer on the supply roller .
A process cartridge comprising: a developing device that enables electrical connection between the metal plate and the shaft of the supply unit and the same potential therebetween . An image carrier that forms a latent image, a charging device that uniformly charges the surface of the image carrier, an exposure device that exposes the charged image carrier surface based on image data and writes the latent image, and an image carrier A developing device that supplies toner to the latent image formed on the surface and visualizes the image, a transfer device that transfers the visible image on the surface of the image carrier directly or onto an intermediate transfer body, and then transfers the image to a recording medium; An image forming apparatus comprising: a cleaning device that cleans a carrier or an intermediate transfer member; and a fixing device that fixes a toner image on a recording medium.
The developing device regulates a developer carrier provided opposite to an image carrier that forms a latent image, a supply unit that supplies developer to the developer carrier, and a developer amount on the developer carrier. A developing device comprising:
The developer is a non-magnetic one-component developer,
The supply means is a supply roller that contacts the developer carrier and supplies a non-magnetic one-component developer;
In the developing device, a metal plate is provided close to the supply roller so as to face the supply roller in the axial direction of the supply roller and in contact with the developer layer on the supply roller.
A developing device that allows the shaft of the metal plate and the supply means to be electrically connected, and the same potential between them.
An image forming apparatus. The image forming apparatus according to claim 10.
An image forming apparatus comprising a process cartridge that integrally supports at least an image carrier that forms a latent image and a developing device that develops the latent image, and is detachable from the image forming apparatus.

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