JP2014157332A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device which is capable of regulating a developer thin layer to a desired thickness by stably supplying a developer having an electric charge above a certain level to a developing roller, while preventing stay of the developer in the vicinity of a contact part between the developing roller and a regulation member.SOLUTION: The developing device comprises: a developing roller 13 carrying the developer on a surface thereof and conveying the carried developer to a latent image carrier; a supply roller 15 coming into contact with the surface of the developing roller, to charge the developer by friction and supplying and recovering the developer in a contact part with the developing roller; and a plate-like developer regulation member 14 coming into contact with the developing roller and the supply roller, to charge the developer by the friction and regulating the layer thickness of the developer on the surface of the developing roller. The developer regulation member 14 includes a bent part bent at a predetermined angle and the contact part with the developing roller is the bent part. The developer regulation member 14 includes a plurality of through-holes 24 through which the developer can pass in the region from the contact part with the developing roller to the contact part with the supply roller.

Description

  The present invention relates to a developing device and an image forming apparatus including the developing device.

In a developing device constituting an image forming apparatus, as a developing method for visualizing an electrostatic latent image on a photosensitive member with a developer, a developing roller on which a thin layer of the developer is formed is brought into contact with the photosensitive member for development. One using a one-component developer is known.
In addition, as an apparatus configuration for performing this development system, a developing roller, a supply roller that is charged by friction while supplying the developer to the developing roller, and an amount of developer adhering to the developing roller are adjusted (the toner layer is adjusted). There is known a configuration including a regulating member that is charged while being regulated.

  However, when the developer is not sufficiently charged at the stage of supplying the developer from the supply roller to the developing roller, the total amount of the developer that can pass through the regulating member is reduced, so that the developer is formed on the developing roller. The developer layer to be formed may become thin and blurring may occur. Therefore, a technique has been proposed in which the developer is charged in advance using a member that contacts the supply roller (see, for example, Patent Document 1 or 2).

Patent Document 1 discloses a configuration in which a toner charging member for frictionally charging toner conveyed by a supply roller is disposed in contact with the supply roller.
According to this configuration, since the toner conveyed by the supply roller is charged by friction with the toner charging member before being supplied to the developer carrier, the toner is attracted to the developer carrier by an electric force. It is easy to describe that the amount of toner supplied to the developer carrier increases.

  In Patent Document 2, a thin layer regulating roller placed in contact with the supply roller and the developing roller is installed for the purpose of preventing the toner from adhering to the regulating member that regulates the toner on the developing roller and always maintaining a good state. A configuration is disclosed. The thin layer forming roller can be pressed against the developing roller and the supply roller with a desired pressing force, and the charge amount of the toner on the developing roller and the layer thickness of the thin layer can be adjusted through adjustment of the pressing force. Is described.

  However, in the developing device that performs the preliminary charging method using the charging member that contacts the supply roller as described in Patent Document 1, the flow of toner may be hindered by the installed charging member. For this reason, there is a problem that a sufficient amount of developer is not supplied to the developing roller, and there is a problem that toner stays in the vicinity of the developing roller and the charging member, overflows from the gap, and the adhesion amount runs away.

  On the other hand, in a developing device provided with a regulating roller as described in Patent Document 2, preliminary charging can be performed while suppressing clogging of toner by rotation of the regulating roller. Therefore, the contact area becomes larger and the peak pressure tends to be lower than that of the plate-shaped regulating member. For this reason, the thickness of the toner layer on the developing roller tends to be larger than the target value. In addition, since the roller is usually a rigid body, high positional accuracy is required for proper regulation, and when a drive system for the regulation roller itself is provided, there are factors to be controlled such as power transmission and torque problems. Become more. Furthermore, since both the developing roller and the regulating roller rotate, it is difficult to seal the toner at the end. And providing a roller and a drive system becomes a factor which causes the enlargement of an apparatus.

  Accordingly, in view of the above problems, the present invention stably supplies a developer having a predetermined charge or more to the developing roller while preventing the developer from staying in the vicinity of the contact portion between the developing roller and the regulating member, An object of the present invention is to provide a developing device capable of regulating a developer thin layer to a thickness.

  In order to solve the above problems, an image forming apparatus according to the present invention is a developing device that visualizes an electrostatic latent image formed on a latent image carrier with a one-component developer, and has a developer on the surface. And a developer roller that conveys the carried developer to the latent image carrier and a surface of the developer roller to charge the developer by friction, and at the contact portion with the developer roller A plate-like developer regulating member that contacts the developing roller and the feeding roller, charges the developer by friction, and regulates the developer layer thickness on the surface of the developing roller The developer restricting member has a bent portion bent at a predetermined angle, the contact portion with the developing roller is the bent portion, and the contact portion with the developing roller The supply b A developing device, characterized in that it comprises a plurality of through holes developer can pass until the contact portion between La.

  According to the present invention, the developer having a predetermined charge or more is stably supplied to the developing roller while preventing the developer from staying in the vicinity of the contact portion between the developing roller and the regulating member, and the developer has a desired thickness. A developing device capable of regulating a thin layer can be provided.

1 is a cross-sectional view illustrating an example of an image forming apparatus according to an exemplary embodiment. It is sectional drawing which shows an example of a structure of a process cartridge unit. It is a schematic diagram which shows an example of the principal part of the conventional developing device. It is a schematic diagram which shows an example of the principal part of the developing device of this embodiment. It is a schematic diagram which shows an example of the principal part of the developing device of this embodiment. It is a schematic diagram which shows an example of the principal part of the developing device of this embodiment. It is a schematic diagram which shows an example of the principal part of the developing device of this embodiment. It is a schematic diagram explaining an example of the through-hole of a developer control member. It is a schematic diagram explaining an example of the through-hole of a developer control member. It is a schematic diagram explaining an example of the through-hole of a developer control member. It is a schematic diagram which shows an example of the principal part of the developing device of this embodiment.

  A developing device and an image forming apparatus according to the present invention will be described below with reference to the drawings. It should be noted that the present invention is not limited to the embodiments of the examples shown below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art. Any aspect is included in the scope of the present invention as long as the operations and effects of the present invention are exhibited.

[Image forming apparatus]
FIG. 1 shows a color image forming apparatus which is an example of the image forming apparatus of this embodiment.
This color image forming apparatus is a so-called tandem type in which process cartridge units 1 of yellow, cyan, magenta, and black are arranged along an intermediate transfer belt 7. Each process cartridge unit 1 forms a visible image on the intermediate transfer belt 7.
The process cartridge unit 1 is configured to be replaceable by releasing the stopper provided in each.

  The exposure unit 6 exposes the photosensitive drum 2 constituting the process cartridge unit 1 based on the image information, and forms an electrostatic latent image on the surface of the photosensitive drum 2. In the present embodiment, the laser beam scanner type exposure means 6 using a laser diode is used, but the exposure means 6 constituted by an LED array or the like may be used.

A primary transfer bias is applied between the primary transfer roller 8 and the photosensitive drum 2 by a high-voltage power source (not shown), and the developer image on the surface of the photosensitive drum 2 is transferred to the surface of the intermediate transfer belt 7.
The intermediate transfer belt 7 is driven to rotate counterclockwise in the drawing by a drive motor (not shown), and a visible image of each color is sequentially transferred onto the surface to form a full color image. Is done.

  The formed full color image is transferred onto a sheet P as a transfer material by applying a predetermined voltage between the secondary transfer roller 11 and the intermediate transfer belt 7. The image of the developer transferred onto the paper P is fixed by heat and pressure by the fixing device 12 and output.

  Note that the sheet path immediately after the fixing device 12 is branched to the reverse conveyance path. In the double-sided image forming mode, the reverse path is followed and the back surface is transferred again via the secondary transfer roller 11 and then discharged. Paper.

  The developer remaining on the intermediate transfer belt 7 without being transferred by the secondary transfer roller 11 is collected by the transfer belt cleaning means 9.

FIG. 2 is a cross-sectional view showing the configuration of the process cartridge unit 1.
As shown in FIG. 2, the process cartridge unit 1 has a configuration in which a photosensitive drum 2, a charging member 3, a developing device 4, and a cleaning unit are integrally coupled.

The process cartridge unit 1 is filled with a developer manufactured by a pulverization method or a polymerization method (hereinafter also referred to as “toner”) as a developer.
As the toner, silica containing silicon oil can be used as an external additive. By using silicon oil-containing silica as the external additive, effects such as extending the life of the process cartridge unit 1, improving the cleaning property, and improving the transfer efficiency can be obtained.

The photosensitive drum 2 rotates clockwise. The charging member 3 is in pressure contact with the surface of the photosensitive drum 2 and is rotated by the rotation of the photosensitive drum 2.
A predetermined bias is applied to the charging member 3 by a high voltage power source (not shown) to charge the surface of the photosensitive drum 2.
In this embodiment, a contact charging method is used in which the charging member 3 is charged by contacting a roller-shaped member. However, a non-contact charging method in which the charging member 3 and the photosensitive drum 2 are charged in a non-contact state is used. It may be used.

  The photoconductor cleaning means 5 cleans the transfer residual toner on the surface of the photoconductor drum 2.

[Development equipment]
The developing device 4 of the present embodiment is a developing device that visualizes an electrostatic latent image formed on the photosensitive drum 2 that is a latent image carrier with a one-component developer, and contains the developer. A storage chamber 41 and a developer supply chamber 42 provided below the storage chamber 41 are provided. Further, a developer is carried on the surface below, a developer roller 13 that conveys the carried developer to the latent image carrier, and a surface of the developer roller 13 is contacted to charge the developer by friction. 13 is in contact with the supply roller 15 for supplying and recovering the developer, and contacts the development roller 13 and the supply roller 15 to charge the developer by friction, and the developer layer thickness on the surface of the development roller 13 And a plate-like developer regulating member 14 that regulates the above.

A developer stirring member 45 is provided in the developer storage chamber 41. A developer supply port 44 is provided between the developer storage chamber 41 and the developer supply chamber 42 to supply the developer from the developer storage chamber 41 to the developer supply chamber 42 and to perform development. The developer is prevented from being excessively supplied to the developer supply chamber 42.
An agitator 46 for preventing agglomeration of the developer is rotatably provided in the central portion of the developer storage chamber 41 and is rotated in the counterclockwise direction.

  The developing roller 13 is disposed in contact with the photosensitive drum 2, and a predetermined developing bias is applied from a high voltage power source (not shown).

  The surface of the supply roller 15 is covered with, for example, a foam material having a structure having pores (cells), and the developer transported into the developer supply chamber 42 is efficiently attached and taken in, and the development roller 13 prevents the developer from being deteriorated due to pressure concentration at the contact portion with the nozzle 13. The electric resistance value of the foamed material is set to 10 3 to 10 14 Ω.

  An offset voltage is applied to the supply roller 15 as a supply bias with the same polarity as the developer charging polarity with respect to the potential of the developing roller 13. This supply bias acts in a direction in which the precharged developer is pressed against the developing roller 13 at the contact portion with the developing roller 13. However, the polarity of the voltage applied to the supply roller is not limited to this, and the same potential or polarity as the developing roller may be reversed depending on the type of developer.

  The supply roller 15 rotates in the counterclockwise direction to apply and supply the developer adhered on the surface to the surface of the developing roller 13.

For example, a roller coated with an elastic rubber layer is used as the developing roller 13, and a surface coat layer made of a material that is easily charged to a polarity opposite to that of the developer is provided on the surface.
The elastic rubber layer is set to a hardness of 50 degrees or less in accordance with JIS-A in order to keep the contact state with the photosensitive drum 2 uniform, and further to the power of 10 to 10 to 10 in order to act a developing bias. The electrical resistance value is set to a power of Ω, the surface roughness is set to 0.2 to 2.0 μm in Ra, and a required amount of developer is held on the surface.

  The developing roller 13 rotates in the counterclockwise direction and conveys the developer held on the surface to a position facing the developer regulating member 14 and the photosensitive drum 2.

  The photosensitive drum 2 rotates in the clockwise direction, and the surface of the developing roller 13 moves in the same direction as the traveling direction of the photosensitive drum 2 at a position facing the photosensitive drum 2. The thinned developer on the developing roller 13 is conveyed to a position facing the photosensitive drum 2 by the rotation of the developing roller 13, and the developing bias applied to the developing roller 13 and the static on the photosensitive drum 2. In accordance with the latent image electric field formed by the electrostatic latent image, it moves to the surface of the photosensitive drum 2 and is developed.

  The developer remaining on the developing roller 13 without being developed on the photosensitive drum 2 is provided with a sealing seal 47 at a portion where the developer returns to the developer supply chamber 42 again, and the developer is placed outside the developing device 4. Sealed to prevent leakage.

The developer regulating member 14 is pressed against and abuts on the surfaces of the developing roller 13 and the supply roller 15 to thin the developer that has passed under the pressing force and to apply electric charge by frictional charging.
Further, a voltage that is offset to the same polarity as the charging polarity of the developer with respect to the potential applied to the developing roller 13 is applied to the developer regulating member 14 as a regulating bias in order to assist frictional charging.

The developer regulating member 14 is a plate-like member having elasticity and preferably has a thickness of 50 to 200 μm.
Examples of the material of the developer regulating member 14 include metals such as SUS304CSP, SUS301CSP, and phosphor bronze, and polymer materials.

With reference to FIG. 3, problems in the conventional developing device will be described.
FIG. 3A shows a configuration for supplying uniformly charged toner to the developing roller 13 in the conventional developing device, and shows the developing roller 13, the supply roller 15, and the developer regulating member 14.
As a conventional developing device, a configuration in which the developer regulating member 14 contacts only the developing roller 13 and a configuration in which the developer regulating member 14 contacts the developing roller 13 and the supply roller 15 are known. (A) shows the latter example.

A voltage is applied to the supply roller 15 so as to form an electric field that facilitates movement of the toner to the developing roller 13 in order to increase the amount of toner supplied to the developing roller 13 and inject charge into the toner. (Not shown).
A voltage is applied to the developer regulating member 14 so as to form an electric field that facilitates movement of the toner to the supply roller 15 in order to inject charges into the toner and prevent the toner from adhering to the developer regulating member 14. Applied (not shown).

The toner sent from the supply roller contact portion 22 of the developer regulating member 14 to the space defined by the developing roller 13, the supply roller 15 and the developer regulating member 14 is indicated by the arrow (1) in FIG. ) And is charged by the supply nip (nip portion between the developing roller 13 and the supply roller 15) 21 as indicated by an arrow (2). Thereafter, as shown by an arrow (3), the thickness is carried to the developing roller 13 and the developing roller contact portion 23 of the developer regulating member 14 to regulate the thickness to be carried.
In the above flow, the uncharged toner or the weakly charged toner having a weak adhesion to the developing roller 13 is bounced back at the developing roller contact portion 23. However, since the toner flow path is not secured around the developing roller contact portion 23, the toner stays around the developing roller contact portion 23.

On the other hand, since the toner is continuously supplied from the supply roller 15, the powder pressure rises in the space defined by the developing roller 13, the supply roller 15, and the developer regulating member 14, and the developer regulating member 14 is moved to the arrow 27. It will be pushed up in the direction indicated by.
When the developer regulating member 14 is pressed in the direction of the arrow 27, the pressing force against the developing roller 13 decreases, and the weakly charged toner flows out. For this reason, the thickness of the toner layer formed on the developing roller 13 is not sufficiently regulated, and there is a first problem that the toner adhesion amount exceeds a desired value.
Further, as shown in FIG. 3A, in a mode in which the developer regulating member 14 is in contact with the developing roller 13 in a plane, the contact area is increased and the peak pressure of the pressing force is lowered. There is a second problem that the thickness of the toner layer formed is not sufficiently regulated, and the toner adhesion amount exceeds the desired value.

The configuration of the present embodiment that solves the first problem described above will be described with reference to FIG.
As shown in FIG. 4, in the developing device of this embodiment, the developer regulating member 14 includes a plurality of through holes through which the developer can pass between the developing roller contact portion 23 and the supply roller contact portion 22. 24.
The arrows in the figure indicate the rotation directions of the developing roller 13 and the supply roller 15.

  By providing the through hole 24, the space defined by the developing roller 13, the supply roller 15, and the developer regulating member 14 is not blocked, and excess toner flows out through the through hole 24. As a result, an increase in the toner pressure in the supply nip 21 can be prevented, and the developer regulating member 14 can be prevented from being pushed up.

The shape of the through hole will be described with reference to FIG.
As shown in FIG. 8A, a plurality of through holes 24 are arranged in the developer regulating member 14 along the rotation axis direction of the developing roller 13 and the supply roller 15.
The through hole 24 is preferably provided close to the developing roller contact portion 23 in order to efficiently release the toner pushed back by the developing roller contact portion 23 in the direction of the arrow 31. Specifically, it is preferably provided in a region between the approximate center of the distance between the axes of the developing roller 13 and the supply roller 15 and the developing roller contact portion 23.

8B and 8C are schematic views of a cross section of the through hole 24. FIG.
The purpose of the through-hole 24 is to feed toner in the direction of the arrow 31, and therefore the opening diameter or opening width d of the surface of the through-hole 24 facing the developing roller 13 and the supply roller 15 and the opening diameter of the opposite surface. Or it is preferable that the opening width D is D> d.
By setting the opening dimension to D> d, it is possible to achieve a structure in which the toner does not easily enter from above in the figure due to the cross-linking characteristics of the powder, but is not limited thereto.

  For example, a through-hole 24 formed in a tapered shape as shown in FIG. 8B, a through-hole 24 perforated so that an opening end as shown in FIG. It is not limited to.

The number of the through holes 24 is not particularly limited and can be appropriately selected.
Further, the opening size of the through hole 24 can be appropriately designed according to the conditions such as the toner particle diameter and the toner supply amount, and can be different for each through hole.
Further, the shape of the through hole 24 is not limited to the circular shape shown in FIG. 8, and may be a square with high alignment and hole coverage, and may be another shape such as an ellipse or a rectangle. .

The method for forming the through hole 24 is not particularly limited, and can be appropriately selected according to the material of the developer regulating member 14 and a desired opening shape. For example, an etching method, a pressing process, a punching process, and the like. , Machining methods such as drilling,
Etc.

The toner supplied without passing through the through hole 24 is conveyed to the supply roller contact portion 22 of the developer regulating member 14 by the supply roller 15 rotating in the direction of the arrow. The toner is preliminarily charged by receiving friction between the developer regulating member 14 and the supply roller 15 at the supply roller contact portion 22. The charged toner is more strongly biased at the supply nip 21 and moves to the developing roller 13.
The toner adhering to the developing roller 13 enters the developing roller contact portion 23 of the developer regulating member 14 and receives the regulating effect and the charging effect.
In this embodiment, since the toner is sufficiently charged as compared with the conventional toner supply mechanism, even if the linear pressure applied between the developer regulating member 14 and the developing roller 13 is weakened, the developing roller contact portion 23 is used. After passing, a uniformly charged thin toner layer is formed on the developing roller 13.

  Further, the developer regulating member 14 is compatible with a blade-like regulating member that is generally employed, and does not require a significant design change. For this reason, since the increase in the number of members and the increase in the occupied volume of the members can be suppressed to a slight extent, the developing device of the present embodiment can solve the above-mentioned problems while satisfying the recent demands for downsizing the device. it can.

The configuration of the present embodiment that solves the second problem described above will be described with reference to FIG.
As shown in FIG. 5, in the developing device of this embodiment, the developer regulating member 14 has a bent portion bent at a predetermined angle, and the contact portion 23 with the developing roller is the bent portion. The developer regulating member 14 has at least one bent portion, and the bent portion contacts the developing roller 13, but may further include another bent portion.

The bending angle θ of the bent portion of the developer regulating member 14 that contacts the developing roller 13 is preferably 5 to 85 °.
The peak pressure can be increased by bringing the bent portion of the bent portion into contact with the developing roller 13, and the function of regulating the toner on the developing roller 13 can be improved. Further, since the charge of the developer can be adjusted by bending the developer regulating member 14, the developer roller 13 is charged with a simple configuration while preventing the developer from staying near the regulating portion of the developing roller 13. By supplying the developed developer, a thin developer layer having a certain charge or more can be formed on the developing roller 13. Further, since the developer regulating member 14 also makes contact with the supply roller 15 to perform preliminary charging, high regulation capability and preliminary charging capability can be obtained with a simple structure including fewer parts.
If the bending angle θ is less than 5 ° or greater than 85 °, the above-described sufficient toner layer thickness regulation and charging adjustment effects cannot be obtained.

  Since the developer regulating member 14 is a plate-like member having elasticity, it is possible to apply a regulation pressure higher than a certain level even if the positional accuracy is not high, and since it is plate-like, it is small without occupying space. It is advantageous to make.

  FIG. 6 shows an example (A) in which the developer regulating member 14 has two bent portions, and the contact portion 22 of the developer regulating member 14 with the supply roller is the bent portion, or a flange of the bent portion. An example (B) is shown.

FIG. 6A shows an example in which the contact portion 22 of the developer regulating member 14 with the supply roller is a bent portion.
The bending angle θ of the bent portion of the developer regulating member 14 that contacts the supply roller 15 is preferably 5 to 175 °. Note that the bending angle θ is a positive angle in the direction in which the allowable entrance angle of the toner from the supply roller contact portion 22 becomes wider.
The amount of toner that can be supplied can be adjusted by adjusting the bending angle θ. In the example shown in FIG. 6A, the amount of toner that can be taken in increases by increasing the angle of the bending angle θ. To do.
If the bending angle θ is less than 5 ° or greater than 175 °, the above-described effect of increasing the amount of toner that can be taken in cannot be obtained.

FIG. 6B shows an example in which the contact portion 22 of the developer regulating member 14 with the supply roller is a flange portion of the bent portion. The bending angle θ of the bent portion is preferably −5 to −90 °. The bending angle θ is a negative angle opposite to that in FIG. 6A, and is a bending angle in a direction in which the permissible toner intrusion angle from the supply roller contact portion 22 becomes narrower.
By setting the negative bending angle, the allowable entry angle of the toner becomes narrow, but when the developer regulating member 14 comes into contact with the supply roller 15 at the flange portion instead of the bent portion, the contact area increases, and the friction amount of the toner increases. The toner can be charged efficiently.
If the bending angle θ is less than −5 ° or greater than −90 °, the charging effect due to the increase in the contact area cannot be obtained.

As shown in FIG. 11, the bending angle θ of the bent portion is approximately −90 °, and the end portion of the flange portion is disposed in the nip portion (supply nip) 21 between the developing roller 13 and the supply roller 15. Good.
FIG. 11 shows an example in which the end portion of the developer regulating member 14 is arranged so as to bite into the supply nip 21. In this embodiment, the toner is preliminarily charged at the contact portion with the supply roller 15 in the supply nip 21 and preliminarily regulated at the contact portion with the developing roller 13 in the supply nip 21, and then developed by the developer regulating member 14. This restriction is made at the roller contact portion 23.
As described above, by being regulated twice, the charging performance of the toner layer is stabilized, and the linear pressure at the developing roller contact portion 23 of the developer regulating member 14 can be reduced.

A mode in which at least a part of the through hole 24 includes a lid-like member for each through hole will be described with reference to FIGS. 9 and 10.
As shown in FIG. 9B, the lid-like member 26 is disposed at an angle of 30 to 90 ° with respect to the opening surface of the through hole 24, leaving an opening through which the developer can pass.

In the example shown in FIG. 9A, for example, when the through hole 24 is formed, the lid member 26 is processed so as to remain.
Excessive supply surplus toner passes through the through hole 24 in the flow path indicated by the arrow 31 and flows out from the area defined by the developing roller 13, the supply roller 15, and the developer regulating member 14. By providing the lid-like member 26, it is possible to limit the toner that enters from the outside in the direction opposite to the arrow 31, and it is possible to efficiently release excess toner to the outside.
FIG. 9A shows an example in which the through direction of the through hole 24 indicated by the arrow 31 is the direction of the developing roller, but the through direction is not limited to this.

As shown in FIG. 9B, the lid-like member 26 is arranged at an angle of θa (for example, 30 °) or an angle of θb (for example, 90 °) with respect to the opening surface. 26b.
The angle with respect to the opening surface can be appropriately set depending on the shape of the opening and the properties of the toner. For example, if the angle is less than 30 °, it may be difficult to pass the toner. May not be able to limit the intrusion.

FIG. 10 is a diagram illustrating an example in which the penetration direction of the through hole 24 indicated by the arrow 31 is the direction of the supply roller 15.
For example, when the position of the developing roller contact portion 23 is higher than the supply roller contact portion 22 and the developer regulating member 14 is provided to be inclined with respect to the horizontal plane, the penetration direction shown in FIG. By providing the lid-like member 26 in this way, it is possible to prevent the toner supplied in the direction of gravity from entering the region defined by the developing roller 13, the supply roller 15 and the developer regulating member 14.

A through hole is provided closer to the supply roller contact portion 22 than the first through hole group of the through hole 24 provided close to the developing roller contact portion 23 and the first through hole group. An embodiment comprising the second through hole group of the through holes 25 is shown in FIG. 7A is a cross-sectional view, and FIG. 7B is a perspective view.
7A and 7B, similarly to the example shown in FIG. 6A, the developer restricting member 14 has two bent portions, and the developer restricting member 14 has a supply roller. In this embodiment, the contact portion 22 is the bent portion.

The opening diameter or opening width of the through-hole 25 constituting the second through-hole group is 30 to 50% of the inter-axis distance L between the developing roller 13 and the supply roller 15.
Specifically, the arrangement position is preferably provided in a region between approximately the center of the distance between the developing roller 13 and the supply roller 15 and the supply roller contact portion 22. It is also preferable to provide an opening at the vertical position of the supply nip 21.
The second through-hole group is provided to supply more toner to the supply nip 21 through the through-hole 25. Therefore, by selecting the above-described opening size range and opening position, the toner supply can be performed. The amount can be increased.
If the opening diameter or width of the through hole 25 is less than 30% of the distance L between the axes of the developing roller 13 and the supply roller 15, a sufficient toner supply amount cannot be obtained, and the toner is crosslinked. May end up.

  Similarly to the through-hole 24, the number of the through-holes 25 is not particularly limited and can be appropriately selected. The shape is not limited to the circular shape shown in FIG. It may be a shape.

  As described above, the developing device according to the present exemplary embodiment uses the plate-like developer regulating member 14 that is in contact with both the developing roller 13 and the supply roller 15 and has an edge formed as a bent portion. It is possible to perform both functions of regulation and pre-charging with a single member. In addition, since the regulating force increases when the edge of the bent portion abuts against the developing roller and the charge of the developer can be adjusted by the angle of the bending angle, the developer stays in the vicinity of the regulating portion of the developing roller 13. While being prevented, a charged developer is supplied to the developing roller 13 with a simple configuration, and a thin developer layer having a certain level or more of charge can be formed on the developing roller 13.

DESCRIPTION OF SYMBOLS 4 Developing apparatus 13 Developing roller 14 Developer control member 15 Supply roller 21 Supply nip 22 Supply roller contact part 23 Development roller contact part 24 Through hole 26 Cover-like member

JP 2007-062357 A

Claims (10)

A developing device that visualizes an electrostatic latent image formed on a latent image carrier with a one-component developer,
A developing roller for carrying a developer on the surface and conveying the carried developer to the latent image carrier;
A supply roller that contacts the surface of the developing roller, charges the developer by friction, and supplies and collects the developer at a contact portion with the developing roller;
A plate-like developer regulating member that contacts the developing roller and the supply roller, charges the developer by friction, and regulates the layer thickness of the developer on the surface of the developing roller;
The developer regulating member includes a bent portion bent at a predetermined angle, the contact portion with the developing roller is the bent portion, and the contact portion with the developing roller is connected to the supply roller. A developing device comprising a plurality of through holes through which a developer can pass between the contact portions.   The developing device according to claim 1, wherein the through hole of the developer regulating member is provided close to a contact portion with the developing roller.   The through hole of the developer regulating member is in contact with the supply roller rather than the first through hole group provided near the contact portion with the developing roller, and the first through hole group. And the opening diameter or opening width of the through hole of the second through hole group is 30 to the axial distance between the developing roller and the supply roller. The developing device according to claim 1, wherein the developing device is 50%.   The opening diameter or opening width d of the surface of the through-hole facing the developing roller and the supply roller and the opening diameter or opening width D of the opposite surface satisfy a relationship of D> d. Item 4. The developing device according to any one of Items 1 to 3.   5. The developing device according to claim 1, wherein a bending angle of a bent portion of the developer regulating member in contact with the developing roller is 5 to 85 °. The developer restricting member has two bent portions, and a contact portion of the developer restricting member with the supply roller is the bent portion.
6. The developing device according to claim 1, wherein a bending angle of a bent portion of the developer regulating member in contact with the supply roller is 5 to 175 °.   The developer restricting member has two bent portions, and a contact portion of the developer restricting member with the supply roller is a flange portion of a bent portion bent at a bending angle of −5 to −90 °. The developing device according to claim 1, wherein:   The developing device according to claim 7, wherein an end portion of the flange portion is in contact with a nip portion between the developing roller and the supply roller. At least a part of the through hole includes a lid-like member for each through hole,
9. The lid member according to claim 1, wherein the lid member is disposed at an angle of 30 to 90 [deg.] With respect to the opening surface of the through hole, leaving an opening through which the developer can pass. The developing device according to 1.   An image forming apparatus comprising the developing device according to claim 1.

Images