JP3259534B2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device which is used in an electrophotographic image forming apparatus such as a copying machine and a printer, and which makes a toner adhere to an electrostatic latent image on an electrostatic latent image holding member to visualize the image. .

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus such as a copying machine or a printer, an electrostatic latent image is formed on the surface of an electrostatic latent image holding member by a difference in charged potential, and the electrostatic latent image is formed by toner. To develop a visible image. A device used for the development is a developing device, and various types of devices have been proposed and put to practical use so far.

FIG. 13 is a schematic sectional view showing an example of a conventionally used one-component developing apparatus. In this one-component developing device, a developing roll 101 having a rotatable cylindrical sleeve and a magnet roll fixedly supported inside the developing roll 101 is arranged so as to be in pressure contact with the developing roll 101, and the developing roll adsorbed on the developing roll surface is developed. A developer regulating member 102 that regulates the developer and reduces the thickness of the developer is accommodated in a housing 104. In the developer regulating member, a blade made of a soft elastic material is attached to one end of an elastically deformable plate member, and the other end of the plate member is fixed to and supported by a housing. The housing 104 includes the developing roll 101
Is opened at the front side facing the electrostatic latent image holding member 105, and a stirring chamber for conveying and stirring the developer T along the developing roll 101 is formed at the rear. In the stirring chamber, a transport supply member 103 that is disposed in parallel with the developing roll 101 and that transports the developer and supplies the developer to the developing roll 101 while rotating and stirring is provided.

In the above-described one-component developing apparatus, the developer T supplied into the stirring chamber is gradually conveyed by the conveying member 103 toward the other end of the stirring chamber. At the same time, the developer supplied to the developing roll 101 and adsorbed on the surface thereof is frictionally charged by the developer regulating member 102 and formed into a thin layer, and the developing roll 101 is moved to the electrostatic latent image holding member 105.
Is transported to the developing area opposite to. In the developing area, an electric field is formed between the developing roll 101 and the electrostatic latent image holding member 105. In this electric field, the developer is transferred to the electrostatic latent image, and the image is developed. The developer that has not contributed to the development is carried into the housing 104 again with the rotation of the developing roll 101, and is separated from the developing roll 101.

In such a developing device, the developer regulating member must be accurately fixed to the housing in order to uniformly form the developer layer on the surface of the developing roll by the developer regulating member. This requires a lot of time and effort. Even if the developer regulating member is accurately mounted, the developer regulating member may be distorted or the distance from the developing roll may fluctuate due to the deflection of the housing due to the fluctuation of the rotation of the developing roll or a change in temperature. There is a problem that the layer cannot be formed and the charge of the developer becomes non-uniform, causing image unevenness and fog.

In order to solve these disadvantages, Japanese Patent Laid-Open Publication No. Hei.
Japanese Patent No. 309080 discloses that a developer regulating member composed of a rubber member and a member holding the rubber member is provided on the basis of a support shaft of the developing roll, and the rubber member is brought into contact with the developing roll, whereby the rotational vibration of the developing roll is reduced. There has been proposed a developing device capable of forming a uniform developer layer on a developing roll without being affected by the flexure of the housing or the housing. JP-A-5-46019 discloses that a holding member of a developer regulating member and a bearing member for holding a support shaft of a developing roll are mounted on substantially parallel fixed surfaces to form a unit, thereby reducing the size and weight of the apparatus. There has been proposed a developing device capable of improving the mounting accuracy of the developer regulating member in such a case and forming a uniform developer layer on a developing roll without affecting the developer regulating member by slight rotation of the unit.

[0007]

SUMMARY OF THE INVENTION However, Japanese Patent Laid-Open No.
In the developing device described in JP-A-309080, the developer regulating member is provided with reference to the support shaft of the developing roll. However, the adjustment of the contact pressure must be performed after these members are incorporated in the housing. In order to obtain an appropriate linear pressure, labor is required. Also, no consideration is given to the exchange of the developing roll and the developer regulating member and the clogging of the abutting portion of the developer regulating member with foreign matter. Also, Japanese Patent Application Laid-Open No. 5-46
The developing device described in Japanese Patent No. 019 is configured with a complicated structure because both the bearing holding member and the developer layer regulating member are attached to the holding portion and the relative positions of the two members can be adjusted. No clogging is considered.

Further, a disadvantage of the above-described one-component developing apparatus is that a pressure (hereinafter referred to as a linear pressure) at the tip of the developer regulating member for the purpose of extending the life of the sleeve of the developing roller and the developer regulating member and using the capsule toner is used. This is particularly problematic when the value is lowered. On the other hand, even if the linear pressure is reduced, the life of the sleeve and the developer regulating member is still insufficient with respect to the life of the copying machine main body, and it is necessary to periodically replace them. In this case, if it is impossible to replace only the sleeve and the developer regulating member, the entire developing device has to be replaced, which results in unnecessary costs. In addition, with the use of these devices, toner agglomerates and foreign matters may be clogged in the contact portion of the developer roll at the leading end of the developer regulating member, causing white spots or the like on a copy. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object that the contact pressure of the developer regulating member is affected by the flexure of the housing during use and the rotational vibration of the developing roll. It is another object of the present invention to provide a developing device capable of forming a high-quality image without any problem, and to provide a developing device capable of performing maintenance and maintenance at low cost in addition to the above.

[0010]

According to another aspect of the present invention, there is provided a developing device, comprising: a housing having an opening at a position facing an electrostatic latent image holding member; A developing roll that is supported so as to be able to expose a part of the peripheral surface from the opening and that faces the electrostatic latent image holding member; And a developer regulating member that forms a thin layer of developer on the surface of the developing roll, wherein a regulating member support that supports the developer regulating member is supported on a support shaft of the developing roll. is supported in combination as the axis of rotation about is possible, the support shaft of the developing roll, the regulating member support and union
It is detachably supported by the housing in a stretched state ,
The regulating member support is driven by rotation of the support shaft.
When the rotational force is transmitted, the housing or the how
The rotation is restricted by being abutted against a member fixed to the jing .

Further, the developing device according to claim 2, in the developing device according to claim 1, wherein a blade developer regulating member is pressed against the developing roller, the blade, after the completion of development, the With respect to the developing roll, the blade is moved in a direction substantially tangential to the pressure contact position of the blade or in a position slightly downstream from the pressure contact position in the rotation direction of the developing roll.

According to a third aspect of the present invention, in the developing device according to the second aspect, the developing roll is set to rotate in a direction opposite to that during development after completion of the development. The blade is pressed against the developing roll so that the rotational force of the developing roll is transmitted to the blade by friction, and the blade moves with respect to the developing roll.

In the first aspect of the present invention, the rotation of the regulating member support is restricted, but the rotation is restricted.
As means , a locking member for stopping the rotation of the regulating member support may be attached to a part of the housing, or the rotation may be restricted by an upper lid of the housing or the like in view of the design of the apparatus.

[0014]

In the developing device according to the first aspect of the present invention, the regulating member support for supporting the developer regulating member is supported by the supporting shaft of the developing roll such that the supporting shaft can rotate.
When the regulating member support of the housing tries to rotate,
Rotation is restricted by hitting
Therefore , even if the housing is distorted or the developing roll is rotated, the developer regulating member is not distorted and the positional relationship between the developing roll and the developer regulating member is kept constant without variation. Therefore, the contact pressure of the developer regulating member is kept constant, and the thickness and charge amount of the developer layer formed on the surface of the developing roll become uniform. Further, since the assembly of the developing roll and the regulating member support is detachably supported by the housing, it is possible to replace only the developing roll and the developer regulating member having a shorter life than other parts, and to reduce Maintenance can be done at cost. In addition, the contact pressure between the developer regulating member and the developing roll can be adjusted before being incorporated in the developing device as an assembly, so that the adjustment is easy and the labor is greatly reduced.
Further, since the rotation of the regulating member support is restricted by the upper cover and the locking member of the housing, the developer is regulated at a fixed position without the developer regulating member rotating together with the rotation of the developing roll.

Further, in the developing device according to the second aspect, the developer regulating member is a blade which is pressed against the developing roll, and after the development is completed , the developer regulating member is located substantially in a tangential direction of the pressing position of the blade or slightly downstream in the rotation direction of the developing roll. Since the position can be moved by a predetermined amount in the tangential direction, toner aggregates and foreign substances clogged at the blade tip can be removed, thereby preventing white spots on the copy and the like.

According to a third aspect of the present invention, since the developing roll rotates in a direction opposite to that during the development after the development is completed, the surface of the blade tip which comes into contact with the developing roll changes so that the blade tip can be cleaned and clogging of aggregates or the like is prevented in advance. can do. In addition, since the rotational force of the developing roll is transmitted to the blade by friction and the blade and the regulating member support can move with respect to the developing roll, the blade can be moved without the need for special driving means when the developing roll is rotated in the reverse direction. You can move against.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a one-component developing apparatus according to an embodiment of the present invention. The developing device includes a developing roller 1 provided at a position facing the electrostatic latent image holding member 5 such that a part of the outer peripheral surface is exposed from the housing 4.
The main part is composed of a developer stirring means 3 disposed in a housing 4 on the back side and a developer regulating member 2 which is pressed against the developing roll 1 to thin and charge the toner. .

The developing roll comprises a magnet roll 1b having a plurality of magnetic poles and fixedly supported by a support shaft 7, and a sleeve 1a rotatable on the circumferential surface of the magnet roll 1b.
As shown in FIG. 2, the developer regulating member 2 includes a blade 2a made of a soft elastic material and a leaf spring 2b supporting the blade near one end, and the other end of the leaf spring 2b is made of sheet metal or resin. It is fixed to the holder with adhesive or screws.

Opposite circular holes are provided at both ends of the holder, and the holder is rotatably supported on the support shaft of the developing roll by mounting the holes on the support shaft 7 of the developing roll. . A member such as a bearing 9 may be used in the holes at both ends of the holder as shown in FIG. 3, and both ends of the holder have semicircular notches as shown in FIG. Alternatively, this may be attached by being locked to a support shaft of a developing roll. Further, in this embodiment, in order to make it easier to attach the holder 6 to the support shaft of the developing roll, the holder 6 can be divided near one end as shown in FIG.

The thus-assembled developing roll, developer regulating member and holder are housed in a housing 4 as shown in FIG.
Positioning holes 12 provided in both side walls of
The support shaft 7 of the developing roll is inserted into the housing, and the bearing 11 is inserted from the outside of the housing.
2 is rotatably engaged and supported. Further, in this embodiment, a horizontally long locking member 10 for preventing the holder from rotating in conjunction with the developing roll is provided above the positioning hole 12 of the housing 4, as shown in FIG. As described above, the rotation of the holder may be restricted by the upper lid 13 of the housing to prevent the holder from rotating, and the shape is not particularly limited as long as the shape can restrict the rotation of the holder.

In the developing device described above, the developer is agitated by the developer agitating means 3 and given a sufficient charge to be supplied to the sleeve 1a on the surface of the developing roll 1. The developer supplied to the sleeve 1a is conveyed to the contact position of the developer regulating member by rotation of the sleeve, and the amount of the developer is regulated by the developer regulating member 2 and charged by friction. Thereafter, the developer is sent to a developing area facing the electrostatic latent image holding member 5, and the developer is transferred to the latent image portion by the action of an electric field formed between the developing roll and the electrostatic latent image holding member, and development is performed. Will be

In the developing device having the above-described structure, the holder and the blade are not distorted and the relationship between the developing roll and the developer regulating member is always kept constant even when the housing is bent or the developing roll rotates. Therefore, a uniform developer layer can be formed on the developing roll. Therefore, the obtained image is also a uniform image without unevenness or fog. In addition, the developing roller and the developer regulating member having a short life are combined into one assembly in advance,
Because these can be attached and detached as one,
During maintenance, these components can be replaced without the need for labor for positioning, and only necessary parts can be replaced. Therefore, the apparatus can be maintained easily and at low cost.

FIG. 8 is a schematic structural view showing a developing device according to an embodiment of the present invention. The developing device includes a developing roller 21 having a part of an outer peripheral surface exposed from a housing 24 at a position facing an electrostatic latent image holding member 25, and a developer agitating unit disposed in the housing 24 on the back side. 23 and a developer regulating member 22 which is pressed against the developing roll to thin and charge the toner, the main part of which is formed, and is opposed to both ends of a holder 26 which fixes the developer regulating member 22. The present embodiment has the same configuration as that of the above-described embodiment except that the formed hole is a long hole 28 and that the sleeve of the developing roll is set to rotate slightly in the opposite direction after the development is completed.

In the developing device described above, the developer supplied to the sleeve 21a is conveyed to the developer regulating member 22 by rotation of the sleeve, as in the embodiment shown in FIG. The developer regulating member 2
The force to move the holder 2 to the downstream side works, and the holder 2
6 is maintained in a state of being pushed upward. Then, in this state, the regulation of the developer and the formation of the thin layer are performed. When the sleeve rotates in the reverse direction after the end of the developing operation, a force acts to pull down the developer regulating member, and the holder is locked to the support shaft 27 by the elongated hole 28, so that the holder moves downward together with the developer regulating member. I do.

FIGS. 9A and 9B are diagrams for explaining this. FIG. 9A shows the relationship between the developing roller and the developer regulating member during the developing operation and FIG. 10B shows the relationship between the developing roller and the developer regulating member during the non-operating time. This is an example of a member, and the developer regulating member moves during operation and non-operation. In FIG.
1 is a development roll, 42 is a developer regulating member, 46 is
Denotes a holder, and reference numeral 48 denotes a long hole. In the present embodiment, the predetermined amount of movement is determined by the longitudinal diameter of the long hole,
It may be regulated by a locking member fixed to the housing or a part of the housing. In the developing device as described above, not only can a uniform developer layer be formed on the developing roll, but also the position of the blade moves during operation and non-operation, so that toner aggregates and foreign substances clogged at the blade tip can be removed. As a result, it is possible to prevent the image to be formed from being whitened or the like.

Next, means for rotating the sleeve in the reverse direction after the end of the developing operation in the above embodiment will be described. As a means for rotating the sleeve in the reverse direction, the drive motor may be set to rotate in the reverse direction, but is retracted from a position close to the image carrier when the developing device is not operated. At times, the sleeve can be rotated in the opposite direction in conjunction with the retracting operation.

FIGS. 11 and 12 are views for explaining a mechanism in which the developing roll rotates in reverse during retraction. 11A shows a state in which the developing operation is being performed, and the developing roller is driven by the counterclockwise driving force of the output gear 14 in the idler gear 1.
7, which rotates the developing roll drive gear 16 counterclockwise, and the sleeve also rotates. Immediately after the end of the operation, these rotations are all stopped [the state shown in FIG. 8B], and then the developing device 15 is turned to
Retract in the direction indicated by the arrow in the figure.

At this time, since the output gear 14 is in a stopped state, it does not rotate, and the idler gear 17 which moves together with the developing device is provided.
Rotates counterclockwise to rub against it, and this is transmitted to the developing roll drive gear 16, and the developing roll rotates clockwise,
That is, it rotates in the opposite direction to the operation.

FIG. 12 shows an example in which the idler gear is not used. However, the developing roll can be similarly reversed without using the idler gear depending on the positional relationship between the driving motor and the developing roll driving gear, the direction of the retraction, and the like. In addition, as a method of rotating the developing roll in the reverse direction, a method of retracting the developing device and then rotating the developing device in a reverse direction by using a repulsive force of a spring may be used. According to the developing device of this embodiment, the blade moves during non-operation and the developing roll can be retracted so that the developing roller can be rotated in the opposite direction to that during development during non-operation. Can be removed and white streaks can be prevented from occurring in the developed image.

[0030]

As described above, in the developing device according to the first aspect of the present invention, the developing roll and the developer regulating member are formed as a single assembly even when the housing is distorted or the developing roll rotates. The developer regulating member moves, and is kept constant without distortion, and the positional relationship between the developing roll and the developer regulating member does not change. Therefore, the thickness and charge amount of the developer layer formed on the surface of the developing roll become uniform.
Also, since only the developing roller and developer regulating member, which have a shorter life than other parts, are integrated in advance and can be replaced as an assembly, maintenance is easy and lower than replacing the entire developing device as before. Can be maintained at cost.

Further, in the developing device according to the second aspect, a predetermined amount of movement is possible in the tangential direction substantially at the tangential direction of the pressure contact position of the blade of the developer regulating member or at a position slightly downstream in the rotation direction of the developing roll. As a result, toner aggregates and foreign matter that have clogged at the pressure contact position of the blade during the movement come off, and it is possible to prevent the occurrence of white spots in the copy due to these.

According to a third aspect of the present invention, since the developing roll rotates in the direction opposite to the developing direction after the completion of the development, the surface of the blade contacting the developing roll changes, thereby preventing clogging or the like from being clogged at the pressure contact position of the blade in advance. be able to. In addition, since the rotational force of the developing roll is transmitted to the blade by friction, and the blade and the regulating member support can move with respect to the developing roll, the blade can be moved with respect to the developing roll without providing special driving means, and the configuration is complicated. Does not.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a one-component developing apparatus according to an embodiment of the present invention.

FIG. 2 is an assembly diagram of a developer regulating member, a regulating member support, and a developing roll used in the developing device of the embodiment.

FIG. 3 is an assembly diagram showing an example of a structure for engaging a developing roll and a regulating member support used in the developing device of the embodiment.

FIG. 4 is an assembly view showing another example of a structure for engaging a developing roll and a regulating member support used in the developing device of the embodiment.

FIG. 5 is a diagram showing a state in which an assembly of a developing roll and a regulating member support is attached to a housing in the developing device of the embodiment.

FIG. 6 is an enlarged view showing a housing of the developing device of the embodiment.

FIG. 7 is a schematic configuration diagram showing a one-component developing device according to another embodiment of the present invention.

FIG. 8 is a schematic configuration diagram showing a developing device according to an embodiment of the invention described in claim 2 or 3;

FIG. 9 is a view for explaining operations of a developing roll, a regulating member support, and a developer regulating member in the embodiment shown in FIG. 8;

FIG. 10 is a view for explaining operations of a developing roll, a regulating member support, and a developer regulating member in a developing device according to another embodiment of the second or third aspect of the present invention.

FIG. 11 is an explanatory diagram showing an example of an operation of rotating the sleeve in the reverse direction in the embodiment shown in FIG.

FIG. 12 is an explanatory view showing another example of the operation of rotating the sleeve in the reverse direction in the embodiment shown in FIG.

FIG. 13 is a schematic sectional view showing an example of a conventional one-component developing device.

[Explanation of symbols]

 1,21 developing roll 2,22 developer regulating member 5,25 electrostatic latent image holder 6,26 regulating member support 10,30 locking member

Continuation of front page (56) References JP-A-5-46019 (JP, A) JP-A-1-108570 (JP, A) JP-A-3-103882 (JP, A) JP-A-4-255877 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 15/08-15/095

Claims (3)

(57) [Claims] A housing having an opening at a position facing the electrostatic latent image holding member; a housing rotatably supported within the housing; and a part of a peripheral surface being exposed from the opening to hold the electrostatic latent image. A developing roll disposed so as to face the body, and a developer regulating member supported on the peripheral surface of the developing roll so as to be in pressure contact with or approaching / separating therefrom and forming a thin layer of developer on the surface of the developing roll. In the developing device, a regulating member support that supports the developer regulating member is supported by being combined with a supporting shaft of the developing roll so as to be rotatable around the supporting shaft. Combined with the regulating member support
The restricting member support is detachably supported by the housing in the fitted state, and is rotated by the rotation of the support shaft.
When a rolling force is transmitted, the housing or the housing
A developing device, which abuts against a member fixed to the ring to restrict rotation. 2. The developing device according to claim 1, wherein the developer regulating member is a blade that is pressed against a developing roll, and the blade is pressed against the developing roll after the development is completed. A developing device which is moved in a tangential direction at a position slightly downstream in a rotation direction of the developing roll from a substantially tangential direction or a pressing position of the developing roller. 3. The developing device according to claim 2, wherein the developing roll is set to rotate in a direction opposite to a direction at the time of development after completion of the development, and a rotational force of the developing roll is caused by friction. The developing device, wherein the blade is pressed against the developing roll so that the blade is transmitted to the blade and the blade moves with respect to the developing roll.