JP3272126B2 - One-component developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to PPC, PPF, LB
The present invention relates to a one-component developing device employed in an electrophotographic image forming apparatus such as P, and more particularly, to prevention of developer scattering in a one-component developing device using a non-magnetic one-component developer.

[0002]

2. Description of the Related Art First, a description will be given of the optimal amount of non-magnetic one-component developer (hereinafter referred to as "toner") to various members and the optimal amount of charge in a conventional non-magnetic one-component developing system. In general, the amount of toner adhering to the transfer paper is 0.5 to 0.5.
7 mg / cm ² is required, which requires 0.6
~ 1.0 mg / cm ² is required. However, for example, JP-A-60-229057 and JP-A-61-2267.
In the conventional example of Japanese Patent Application Laid-Open No. H08-209, the amount of toner adhered on the developer carrier is as small as 0.2 to 0.5 mg / cm ^2, and a sufficient amount of toner adhered on the developer carrier cannot be obtained. In addition, there is a problem that a desired amount of toner adhered to transfer paper cannot be obtained. For this reason, conventionally, the surface moving speed of the developer carrying member is set to be 2 to 4 times the surface moving speed of the photosensitive member, so that even if the amount of toner adhering on the developer carrying member is insufficient, A desired amount of toner is adhered to the transfer paper so that the amount of toner on the transfer paper does not become insufficient.

However, when the surface of the developer carrying member is moved at a speed ratio of 2 to 4 times as described above, the density at the rear end of the image becomes high when the solid portion is developed, so-called "toner rear end". There is a defect that the phenomenon occurs. Although the "toner trailing edge" phenomenon caused by making the surface moving speed of the developer carrying member higher than the surface moving speed of the photoreceptor has not been solved yet, it has been accepted, although it has been a problem in the conventional monochrome image machine. Was. However, in a color image machine, the color image is transmitted through the toner, so that the density is high at the rear end of the image. In particular, in the case of a superimposed image, the color is different. Leaning is a big problem.

In order to prevent the occurrence of the "toner trailing edge" phenomenon, the amount of toner adhering to the developer carrier is increased, and the surface moving speed of the developer carrier is reduced to the surface moving speed of the photosensitive member. It is necessary to perform the development in close proximity, that is, to perform the uniform development.

In order to increase the speed of the image forming apparatus, the surface moving speed of the photosensitive member is increased, and accordingly, the surface moving speed of the developer carrier is reduced to, for example, 2 to 4 times the surface moving speed of the photosensitive member. Then, various troubles accompanying the driving of the developer carrier may occur. Therefore, constant speed development is required also from the viewpoint of speeding up the image forming apparatus.

[0006]

Here, at the time of the above-mentioned constant speed development, at least 0.8 mg / cm ² (contact development method with high development efficiency) to 1.0 mg / cm ² or more (developing In order to obtain this amount of toner, the thickness of the toner layer on the developer carrier must be two or more. The most important thing at this time is that the toner in the upper layer portion is also all charged, has no uncharged toner, and a charge amount of 5 to 15 μc / g with a stable charge distribution is desired. If there is an uncharged toner, the transfer of the development is poor, the background is stained, and the resolution is deteriorated.

Therefore, the present applicant has previously filed Japanese Patent Application No. 2-151.
No. 10 disclosed a novel development method. In this method, a dielectric portion and a grounded conductive portion which are regularly or irregularly distributed over a small area are provided on the surface of the developer carrier, and the surfaces of the developer carrier and the developer supply member are brought into contact with each other and moved. Thereby, a large number of minute electric fields are formed near the surface of the developer carrying member due to frictional charging between the developer supplying member and the toner, and the frictionally charged toner rubbed with the developer carrying member is supplied with the developer. The developer is supplied to the surface of the developer carrier by a member,
The electrostatic latent image is visualized by the toner carried on the developer carrier. According to this, two or more toner thin layers having a stable adhesion amount and a stable charge amount can be formed on the surface of the developer carrying member by the small electric field, and the system can be stabilized and the image quality can be improved. It became.

In particular, when two or more toner layers are formed on the surface of the developer carrier as described above, a developer container (hereinafter, referred to as a toner hopper) starts from the longitudinal end of the developer carrier. In order to prevent the developer from leaking out of the developing device and contaminating the inside of the image forming apparatus, it is necessary to contact the end portion of the developer carrier with a side plate of a toner hopper via a seal member. The end seal has conventionally been made of a felt-based or sponge-based material. The wider the contact width of the seal member in both the axial direction (longitudinal direction) and the rotational direction of the developer carrying member, the better the sealing property and the less the developer leaks even after long-term use. Further, even if the thickness of the sealing member is increased to increase the sealing pressure, the developer sealing property is improved. However, when the above-described treatment for improving the sealing performance at the end portion is performed, the driving torque of the developer carrying member is increased at the same time, and thus, for example, uneven rotation of the developer carrying member causes jitter on an image or sudden occurrence of gear jump or the like. Accidents are more likely to occur. For this reason, there is a problem that the drive motor and the device become large and the cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to prevent the developer from leaking from the longitudinal end of the developer carrier and increase the driving torque. It is an object of the present invention to provide a one-component developing apparatus which can be used for a long period of time with a simple structure. Another object of the present invention is to obtain an optimum amount of adhesion and charge amount of the developer on the developer carrier, and to prevent leakage of the developer from a longitudinal end of the developer carrier and a driving torque. It is an object of the present invention to provide a one-component developing apparatus which prevents a rise in the temperature and enables a long-term use with a simple structure.

[0010]

[0011]

[0012]

[0013]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
In the invention of claim 1, an auxiliary agent is externally added as necessary.
A one-component developer, carrying the developer on the surface,
A developer carrier that transports the developer to the development area by moving
And a longitudinal end of the developer carrying member is provided with a developer collecting member.
The developer is brought into contact with the side plate of the container via a seal member.
A one-component developing device configured to seal
A bristle-brush-shaped member is provided on a surface of the seal member facing the longitudinal end of the developer carrier, and the length of the bristle brush is downstream from the upstream side in the surface movement direction of the developer carrier. set such side is long and is characterized in that it has to be higher toward the downstream side from the surface moving direction upstream side of the developer carrying member to the developer sealing performance of the seal member.

The invention according to claim 2 provides an auxiliary agent if necessary.
An externally added one-component developer, carrying the developer on the surface,
As the surface moves, the developer is conveyed to the development area.
An image agent carrier, and a longitudinal end of the developer carrier is
By contacting the side plate of the developer container with a seal member
One-component developing device configured to seal the developer
A brush-like member is provided on a surface of the seal member facing the longitudinal end of the developer carrier, and the density of the bristle brush is higher than that of the developer carrier on the surface movement direction upstream side. set so downstream is higher and is characterized in that it has to be higher toward the downstream side from the surface moving direction upstream side of the developer carrying member to the developer sealing performance of the seal member.

[0015]

[0016]

[0017]

[0018] The invention according to claim 3 provides an auxiliary agent if necessary.
An externally added one-component developer, carrying the developer on the surface,
As the surface moves, the developer is conveyed to the development area.
And an image carrier, and charges the surface of the developer carrier.
Exposing the holding dielectric part and the grounded conductive part
And a large number of minute portions formed by the dielectric portion and the conductive portion.
Forming a closed electric field and developing the developer with the minute closed electric field;
Visualizes electrostatic latent images by holding them in multiple layers on the surface of the agent carrier
A one-component developing device, the developing device corresponding to a non-image area.
At the longitudinal end of the agent carrier, the current corresponding to the image area
The minute electric field is weakened from the longitudinal center of the image carrier.
Or, the micro-closed electric field is eliminated, and at the longitudinal end of the developer carrier corresponding to the non-image area, the electric charge held by the dielectric portion provided at the end is charged. A charge removing member is provided for removing the charge.

[0019]

According to the first or second aspect of the invention, the sealing property of the seal member interposed between the longitudinal end of the developer carrier and the side plate of the developer container is determined by the direction of movement of the surface of the developer carrier. It is set to be higher from the upstream side to the downstream side, that is, the adhesion between the developer carrier and the seal member is set to be higher on the downstream side in the direction than on the upstream side in the direction. Since a part of the seal member is in close contact with the surface of the developer carrier on the downstream side in the direction, the driving load of the developer carrier is smaller than when the entire surface of the seal member is in close contact with the surface of the developer carrier. It can be made small and almost the same sealing performance can be obtained. That is, even if the developer enters from a location (upstream in the direction) in which the seal member has low adhesion to the surface of the developer carrier, the developer that has entered enters from the upstream side in the direction according to the surface movement of the developer carrier. Since the developer is prevented from leaking at a part of the downstream side in the direction, the developer in the developer container leaks from the longitudinal end of the developer carrier to the outside. No good sealability is obtained.

[0020]

[0021]

In particular, in the first aspect of the present invention, a bristle-brush-like member is provided on a surface of the seal member facing a longitudinal end of the developer carrier, and the length of the bristle brush is reduced by the developer. Since the downstream side is set to be longer than the upstream side in the surface movement direction of the carrier, the bristle brush fibers adhere to the surface of the developer carrier by the surface movement of the developer carrier in the downstream portion of the seal member in the direction. As a result, it is possible to prevent the developer from leaking to the outside, and to reduce the adhesion of the bristle brush to the surface of the developer carrier at the upstream portion of the seal member to develop all the bristle brushes. The driving load of the developer carrier can be reduced as compared with the case where the developer carrier is brought into close contact with the surface of the developer carrier.

Further, in the invention of claim 2, the bristle brush-like member is provided on a surface facing the longitudinal end of the developer carrying member of the seal member, the developer carrying the density of said capillary brush Since the downstream side is set higher than the upstream side in the body surface movement direction, the adhesiveness of the bristle brush to the surface of the developer carrier is increased at the downstream side of the seal member so that the developer is When the bristle brush can be prevented from leaking well, and the bristle brush is reduced in adhesion to the surface of the developer carrier at the upstream portion of the seal member, so that all the bristle brushes adhere to the surface of the developer carrier. As a result, the driving load of the developer carrying member can be reduced.

[0024]

According to the third aspect of the present invention, the developer carrying member provided on the surface such that the dielectric portion and the conductor portion are mixed regularly or irregularly with a small area is provided by the developer or the developer carrying material. Electric charges are induced in the dielectric portion by frictional charging with a developer supply member that supplies the developer to the body, and a minute closed electric field is formed between the dielectric portion and the conductive portion. Then, the developer carrier can carry the developer in multiple layers by the large number of micro-closed electric fields formed in this way, and can transport the multilayer developer to visualize the electrostatic latent image. Further, at the longitudinal end of the developer carrier corresponding to the non-image area, the minute closed electric field is weaker than the central part in the longitudinal direction of the developer carrier corresponding to the image area, or the minute closed electric field is reduced. Since it is eliminated, the adhesive force of the developer to the end of the developer carrier in the direction is weakened. Therefore, for example, when sealing is performed by pressing a seal member against the end portion of the developer carrier in the direction, even if the adhesion of the seal member to the developer carrier is weak, the developer is transferred to the developer carrier by the seal member. It is scraped off from the surface to obtain good sealing properties. Further, since the adhesion of the seal member to the developer carrier can be weakened as described above, an increase in the driving load of the developer carrier can be prevented.

[0026]

Further, the ends in the longitudinal direction of the non-image areas to the corresponding said developer carrying member, a charge removing member for removing the charge held in the above dielectric portion provided on the end portion Therefore, the strength of the minute closed electric field at the end portion in the direction can be reduced, whereby the adhesive force of the developer to the developer carrier can be reduced. Therefore, when a seal member is applied to the end portion of the developer carrier in the direction to seal,
Good sealing properties can be obtained without increasing the adhesion of the sealing member to the developer carrier. Also, since it is not necessary to increase the adhesion of the seal member to the developer carrier,
It is possible to prevent the driving load of the developer carrier from increasing.

[0028]

【Example】

[Embodiment 1] An embodiment in which the present invention is applied to a developing device used in an electrophotographic copying machine (hereinafter referred to as a copying machine) as an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram around a developing device of a copying machine according to the present embodiment. FIG.
FIG. 2 is a perspective view of the developing device in FIG. 2, the illustration of the toner supply roller 4 in FIG. 1 is omitted. The photoreceptor 1 rotates at a linear speed of 200 mm / sec in the direction of the arrow in the figure. The developing roller 2 comes into contact with the toner supply roller 4 and rotates at a linear speed of about 220 mm / sec in the direction of the arrow in the figure. In addition, a lower seal 9 formed to extend in the longitudinal direction of the developing roller 2 is in contact with a lower portion of the developing roller 2. As shown, the toner supply roller 4 rotates in the same direction (forward rotation) as the developing roller 2 at a contact portion with the developing roller 2 at about 0.5 to 2.5 times the speed of the developing roller 2. As described later, frictional charging is applied to the minute dielectric portion of the developing roller 2 by friction with the toner 2 and the toner 7 to create a micro field (small closed electric field) on the developing roller 2. In addition, a potential difference of about 50 to 300 V may be provided between the rollers 2 and 4 so that an electric field in a direction in which the charged toner 7 adheres to the developing roller 2 is formed. In the developing device according to the present embodiment, the toner 7 supplied to a toner container (hereinafter referred to as a hopper) 6 is agitated by an agitator 5 and passed to a toner supply roller 4. The toner supply roller 4 comes into contact with the developing roller 2 and rotates in the direction of the arrow in the drawing to cause frictional charging of the toner 7 and adhesion of the toner 7 to the developing roller 2. The toner 7 charged by the friction between the toner supply roller 4 and the developing roller 2 is electrostatically held by the micro-field formed on the developing roller 2, and the dielectric portion 21 on the developing roller 2 (see FIG. 9) and the edges of the dielectric portion 21 and the conductor portion 22 (see FIG. 9 described later). Then, the toner 7 attached to the developing roller 2 is formed into a uniform layer by the thinning blade 3 and is transported to the developing area.
The latent image on the photoconductor 1 is developed.

Next, the developing roller 2 of this embodiment will be described in detail. As the developing roller 2 of the present embodiment,
For the purpose of increasing the amount of adhered toner, FIG.
As shown in (b), a developing roller 2 is used in which a dielectric portion 21 capable of holding electric charges on its surface and a grounded conductive portion 22 are exposed in a small area in a mixed manner. FIG. 9A is a plan view of the surface of the developing roller 2, and FIG.
FIG. 10B is a cross-sectional view taken along the line aa in FIG. 9A.

The developing roller 2 of this embodiment can be manufactured as follows. First, for example, a 0.3 mm pitch, 0.1 mm depth on the surface of an aluminum cored roller with a roller diameter of 25 mm,
A predetermined groove is formed by performing iris knurling with a groove width of 0.2 mm and an angle of 45 degrees. Then, an epoxy-modified silicone resin (Toray SR2115) is coated on the surface of the aluminum cored roller and dried at 100 ° C. for about 30 minutes. Thereafter, the roller surface is cut to expose the aluminum core portion as the conductor portion 22 and the resin in the groove as the dielectric portion 21 so as to be exposed on the surface. The developing roller 2 according to the present embodiment is configured such that the conductor portion 22 and the dielectric portion 21 have a ratio of 3: 7 in the surface cutting.

When the developing roller 2 is used, the friction between the developing roller 2, the toner 7, and the toner supply roller 4 causes the dielectric portion 21 of the developing roller 2 to be charged with a polarity opposite to the desired toner charging polarity (regular polarity). In development, the charge is of the same polarity as the photoconductor charge, and in reversal development, the charge is of the opposite polarity to the photoconductor charge. In the specific example of the present embodiment, since the reversal development is performed using the toner 7 charged to the negative polarity, the dielectric portion 21 is charged to the positive polarity. Then, as shown by the electric lines of force E in FIG. 9B, a microfield (a minute closed electric field) is formed on the developing roller 2.

On the other hand, since the surface of the toner supply roller 4 moves in the same direction as the surface of the developing roller 2, the toner 7 carried on the toner supply roller 4 rubs between the developing roller 2 and the toner supply roller 4. Most of the charge is charged to a desired polarity (in the normal development, the polarity is opposite to the photoconductor charge, and in the reversal development, the polarity is the same as the photoconductor charge). In the above specific example of the present embodiment, the toner 7 is negatively charged.

Then, the charged toner 7 on the toner supply roller 4 is electrostatically attracted by the micro field (small closed electric field) E on the developing roller 2 and adheres to the surface of the developing roller 2 in multiple layers. As a result, the developing roller 2 comes out of the contact portion with the toner supply roller 4 in a state where the sufficiently charged toner 7 is carried in multiple layers. (Less than,
margin)

By using this developing roller 2,
The micro-field (small closed electric field) E can form and transport a multi-layer toner layer having a stable charge amount on the developing roller 2, so that the difference between the linear speed of the developing roller 2 and the linear speed of the photoconductor 1 is reduced. That is, the linear velocity ratio of the developing roller to the photoconductor can be made close to 1. As a result, it is possible to reduce the ratio of abnormal toner adhesion to the normal solid portion at the portion from the rear end of the toner, and to reduce the density at the portion from the toner rear end. Therefore, it is possible to make the rear end of the toner inconspicuous from both sides of the width and the density. Note that, in the developing roller 2 of the present embodiment having the above configuration, the developing roller 2
On top, M / A (toner mass per unit area) of 1.2 to
At 1.8 mg / cm ² and Q / M (toner charge per unit mass), a toner thin layer having characteristics sufficient for development of −8 to −20 μc / g was obtained.

Incidentally, the developing roller 2 has a function of transporting the toner 7 in the hopper 6 to the outside of the developing device by its rotation. Therefore, when the toner 7 in the hopper 6 is sent to the end of the developing roller 2, as long as the gap formed between the developing device side plate and the end of the developing roller 2 is not closed by, for example, a toner leakage prevention member or the like. In addition, the toner 7 in the hopper 6 leaks from the end of the developing roller 2 through the gap to the outside of the developing device, and it is difficult to use the toner for practical use.

Therefore, in the developing device according to the present embodiment, the length of the developing roller 2 in the axial direction is set so that both ends of the photosensitive member 1 are longer than the image area by about 10 mm.
As shown in FIG. 2, both ends of the developing roller 2 are contacted,
A seal member 8 that seals both ends of the developing roller 2 is provided. FIG. 3 shows the shape of the seal member 8. Here, as the width a of the seal member 8 in the axial direction of the developing roller 2 is larger, the toner 7 on the developing roller 2 is less likely to spread to the end with time, and the sealing property is higher. Further, the length b of the seal member 8 in the rotation direction of the developing roller 2 is changed from a portion in contact with the toner 7 in the hopper 6 of the developing roller 2, that is, from a contact portion 9a between the developing roller 2 and the lower seal 9 in FIG. It is necessary to have a length that sufficiently covers the surface portion of the developing roller 2 up to the contact portion 3a between the blade 2 and the thinning blade 3. Hereinafter, specific examples of the seal member 8 will be described. (1) Seal member width a: 10.5 mm (2) Seal member length b: Contact between the developing roller 2 and the thinning blade 3 from the contact portion 9a between the developing roller 2 and the lower seal 9 (see FIG. 1). Immediately below the contact portion 3a (see FIG. 1) (3) Seal member thickness: 2 mm (4) Amount of penetration of the seal member into the developing roller 2: 0.5 mm (5) Material of the seal member: A bristle brush member is stuck to a sponge.

Here, from the viewpoint of the toner sealing property, it is preferable that the sealing member 8 is in close contact with the surface of the developing roller 2 over the entire length b in the rotation direction of the developing roller 2.
In order to make the rotation of the developing roller 2 smooth, the adhesion of the seal member 8 to the developing roller 2 is preferably low. Therefore, in the present embodiment, as shown in FIG. 4, the lower half of the surface of the seal member 8 in contact with the developing roller 2 in the drawing, that is, the half of the upstream side in the rotation direction of the developing roller 2 (upstream portion A) It is covered with a low friction coefficient sheet 81 such as polyimide or Teflon. As a result, the driving torque of the developing roller 2 was 1.8 kgfcm when the sheet 81 was not covered, and the driving torque of the developing roller 2 was reduced to 1.1 kgfcm. There is almost no leakage of the toner 7 from the end of the roller 2 and the bristle brush surface is not covered with the sheet and the sealing member 8
The same good sealing properties as when the entire surface was exposed were obtained.

Next, a more specific embodiment of a copying machine including the developing device shown in FIGS. (1) Material of toner supply roller 4: foamed polyurethane sponge roller kneaded with carbon (2) Diameter of toner supply roller 4: 16 mm (3) Material of thinning blade 3: urethane rubber (4) Thinning blade 3 Thickness t: t = 2 mm (5) Contact pressure of the thinning blade 3 with the developing roller: 10
20 g / cm (6) Developing gap: 180 μm (7) Developing bias: peak value -12 at DC-700V
(8) One type of photoconductor: OPC, drum type used (9) Surface potential of photoconductor 1: background portion -850V, writing portion (image portion) -100V (10) Toner 7 : Negatively charged toner using non-magnetic styrene acrylic + polyester resin (11) Volume average particle diameter of toner 7: 10 μm (12) External additive of toner 7: SiO2 fine powder 0.5 wt
%

[Embodiment 2] In the present embodiment, only the structure of the seal member 8 is different from that of the first embodiment. Therefore, in the following description, only the structure of the seal member 8 different from that of the first embodiment will be described. Descriptions of other configurations such as the configuration of the developing device will be omitted. That is, in the present embodiment, as shown in FIG. 5, a member entirely made of a sponge material is used as the seal member 8, and the lower half of the surface of the seal member 8 that contacts the developing roller 2, ie, the developing roller 2
The sponge thickness of the half portion (upstream area) on the upstream side in the rotation direction is set to 1.8 mm (the amount of penetration into the developing roller 2 is 0.3 mm).
mm), the sponge thickness of the upper half in the figure, that is, the half of the downstream side in the rotation direction of the developing roller 2 (downstream area) is 2.3.
mm (the amount of penetration into the developing roller 2 is 0.8 mm)
Set to. By doing so, the sealing pressure by the sealing member 8 increases from the downstream side to the upstream side in the rotation direction, and the thickness of the sponge is 2.3 throughout the entire surface.
mm, the driving torque of the developing roller 2, which was 1.6 kgfcm, was suppressed to 0.8 kgfcm.
Developing roller 2 even after it has been used for image formation about 00 times
There was almost no leakage of the toner 7 from the end, and the same good sealing property as when the sponge was thick over the entire surface was obtained.

[Embodiment 3] In the present embodiment, only the structure of the seal member 8 is different from that of the first embodiment. Therefore, in the following description, only the structure of the seal member 8 different from that of the first embodiment will be described. Descriptions of other configurations such as the configuration of the developing device will be omitted. That is, in the present embodiment, as shown in FIG. 6, a member formed by attaching a bristle brush member 83 to the surface of a sponge member 82 is used as the seal member 8, and the surface of the seal member 8 in contact with the developing roller 2 is shown in FIG. The bristle brush length of the lower half, that is, the upstream half of the developing roller 2 in the rotational direction (upstream area) is 1.0 mm, and the upper half in the figure, that is, the downstream half of the developing roller 2 in the rotational direction (downstream area). The bristle brush length is set to 2.0 mm. By doing so, the bristle brush winds around the developing roller 2 from the downstream side to the upstream side in the rotation direction, and when the length of the bristle brush is 2.0 mm over the entire surface, it is 1.6 kgfcm. The driving torque of the developing roller 2 is suppressed to 1.0 kgfcm, the toner 7 hardly leaks from the end of the developing roller 2 even after about 1000 times of image formation, and the length of the bristle brush is , The same good sealing properties as in the case of 2 mm were obtained.

[Embodiment 4] In the present embodiment, only the structure of the seal member 8 is different from that of the first embodiment. Therefore, in the following description, only the structure of the seal member 8 different from that of the first embodiment will be described. Descriptions of other configurations such as the configuration of the developing device will be omitted. That is, in the present embodiment, as shown in FIG. 6, as in the third embodiment, as the seal member 8, a member formed by attaching a bristle brush member 82 to a sponge member surface 81 is used, and the developing roller 2 of the seal member 8 is used.
The bristle brush density of the lower half in the figure of the surface contacting with the surface, ie, the half portion (upstream area) on the upstream side in the rotation direction of the developing roller 2 is 10,000 brushes / cm ² , and the upper half in the figure, ie, the developing roller 2
Is set at 30,000 brushes / cm ² in the half portion (downstream area) on the downstream side in the rotation direction. In this case, the bristle brush density increases from the downstream side to the upstream side in the rotation direction, and the bristle brush density is 30,000 brushes / cm ² over the entire surface.
Was 1.9 kgfcm, the driving torque of the developing roller 2 was suppressed to 1.1 kgfcm.
Even after use for about two times of image formation, there is almost no leakage of the toner 7 from the end of the developing roller 2 and the same good sealing property as when the bristle brush density is 30,000 / cm ² over the entire surface. Obtained.

[Embodiment 5] In the present embodiment, only the structure of the seal member 8 is different from that of the first embodiment. Therefore, in the following description, only the structure of the seal member 8 different from that of the first embodiment will be described. Descriptions of other configurations such as the configuration of the developing device will be omitted. That is, in the present embodiment, as in the second embodiment, a member made of a sponge material as a whole is used as the seal member 8, and the lower half of the surface of the seal member 8 that contacts the developing roller 2, ie, the developing roller 2 The density of the half part (upstream area) on the upstream side in the rotation direction of
0 Kg / m ³ , the density of the upper half in the figure, ie, the half of the downstream side in the rotation direction of the developing roller 2 (downstream area) is 60 kg.
It is set to / m ^3. In this case, the density increases from the downstream side to the upstream side in the rotation direction, and when the density is 60 kg / m ³ over the entire surface, the driving torque of the developing roller 2 was 1.7 kgfcm, which was 0.9 kgfcm. In addition, even after use for about 1,000 times of image formation, there is almost no leakage of the toner 7 from the end of the developing roller 2 and the same good sealing as when the density is 60 kg / m ³ over the entire surface. Sex was obtained.

[Embodiment 6] In the present embodiment, only the structure of the developing roller 2 and the seal member 8 is different from that of the above-mentioned Embodiment 1, and therefore, in the following description, the developing roller 2 and the seal member 8 which are different from the above-mentioned Embodiment 1 will be described. Only the configuration described above will be described, and description of other configurations such as the configuration of the developing device will be omitted. That is, in the present embodiment, as shown in FIG. 7, the knurl grooves 24 are not cut in the non-image areas 23 at both ends in the longitudinal direction of the developing roller 2 so that the roller surface after coating with the epoxy-modified silicone resin is used. After cutting, only the aluminum surface is exposed. In this embodiment, a sponge material having a thickness of 2 mm is used as the seal member 8, and the seal member 8 is disposed so as to bite into the developing roller 2 by 0.5 mm. By doing so, the frictional resistance between the seal member 8 and the developing roller 2 becomes lower than when the knurled groove 24 is also provided in the non-image area 23 of the developing roller 2, and the driving torque of the developing roller 2 is reduced. Is maintained at a sufficiently low value of 1.0 kgfcm, and the non-image area 23 of the developing roller 2 is not formed with the microfield (small closed electric field) E so that the toner is not held. Even after the image forming apparatus was used for forming an image, the toner 7 hardly leaked from the end of the developing roller 2 and a good seal was obtained.

[Embodiment 7] In the present embodiment, only the structure of the developing roller 2 and the sealing member 8 is different from that of the above-described Embodiment 1, and therefore, in the following description, the developing roller 2 and the sealing member 8 which are different from the above-mentioned Embodiment 1 will be described. Only the configuration described above will be described, and description of other configurations such as the configuration of the developing device will be omitted. That is, in the present embodiment, as shown in FIG. 8, a developing roller 2 in which a conductive resin in which dielectric particles are dispersed is applied to an aluminum tube is used. In the developing roller 2 configured as described above, a microfield (small closed electric field) E (see FIG. 9) as in the first embodiment described above between the conductive portion and the conductive portion due to the charge accumulated on the surface of the dielectric particles. ), And the toner 7 can be transported in multiple layers by the microfield (small closed electric field) E. In this embodiment, the dielectric particles are removed from the non-image areas 23 at both ends in the longitudinal direction of the developing roller 2. In this embodiment, a sponge material having a thickness of 2 mm is used as the seal member 8, and the seal member 8 is disposed so as to bite into the developing roller 2 by 0.5 mm. In this way, the driving torque of the developing roller can be suppressed to a sufficiently low value of 1.0 kgfcm, and the non-image area 23 of the developing roller 2 does not have the microfield (small closed electric field) E. Can be kept from
Even after the image formation was performed about once, the toner 7 hardly leaked from the end of the developing roller 2 and good sealing was possible.

[Embodiment 8] In the present embodiment, only the configuration of the developing roller 2 is different from that of the above-described seventh embodiment. Therefore, in the following description, only the configuration of the developing roller 2 that is different from that of the above-described seventh embodiment will be described. Descriptions of other configurations such as the configuration of the developing device will be omitted. That is, in the present embodiment, as in the case of the seventh embodiment, a developing roller 2 formed by applying a conductive resin in which dielectric particles are dispersed to an aluminum tube is used as the developing roller 2, and a non-image at both ends in the longitudinal direction of the developing roller 2 is used. A conductive brush member (not shown) for removing charges accumulated in the dielectric particles is brought into contact with the region 23 (see FIG. 8). The brush member needs to be electrically floated except that the brush member has conduction with the roller core in order to prevent leakage of the developing bias. In this way, the driving torque of the developing roller can be suppressed to a sufficiently low value of 1.1 kgfcm.
Does not form the microfield (small closed electric field) E, and can prevent the toner from being retained.
Even after use for about 0 times of image formation, there was almost no leakage of toner from the end of the roller, and good sealing was possible.

[0046]

According to the first or second aspect of the present invention, the entire surface of the seal member is brought into close contact with the downstream surface portion of the seal member in the direction of movement of the surface of the developer carrier. A one-component developing device that can be used for a long time with a small size, low cost, because the driving load of the developer carrier can be reduced and almost the same sealing performance can be obtained as compared with the case where the developer carrier is closely attached to the surface of the developer carrier. There is an effect that can be provided. According to the invention of claim 3 , two or more thin layers of the developer having a stable amount of adhesion and a stable amount of charge can be formed on the developer carrier by the minute closed electric field formed on the surface. image enhancement of quality is possible and that Do not. Change
In the longitudinal end portion of the developer carrier, the small closed electric field is weakened or the small closed electric field is eliminated, thereby weakening the adhesive force of the developer to the end portion of the developer carrier in the direction, for example, When a seal member is pressed against the end of the developer carrier in the direction to seal the developer, the developer is scraped from the surface of the developer carrier by the seal member even if the adhesion of the seal member to the developer carrier is weak. since good sealing property dropped was to be obtained, a small, Ru can provide usable developing device for a long period of low cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram around a developing device of a copying machine according to an embodiment.

FIG. 2 is a perspective view of a developing device in FIG.

FIG. 3 is an exemplary perspective view showing the outer shape of the seal member according to the embodiment;

FIG. 4 is a schematic configuration diagram of a seal member according to the embodiment.

FIG. 5 is a schematic configuration diagram of a seal member according to another embodiment.

FIG. 6 is a schematic configuration diagram of a seal member according to another embodiment.

FIG. 7 is a schematic configuration diagram of a developing roller according to another embodiment.

FIG. 8 is a schematic configuration diagram of a developing roller according to another embodiment.

FIG. 9A is a plan view of the surface of a developing roller. (B) is sectional drawing when cut | disconnected by the aa cutting line in (a).

[Description of Signs] 1 Photoconductor drum 2 Developing roller 3 Thinning blade 4 Toner supply roller 5 Agitator 6 Hopper 7 Toner 8 Seal member 21 Dielectric part 22 Conductor part 23 Non-image area 24 Knurl groove 81 Low friction coefficient sheet 82 Sponge member 83 Bristle brush member

Claims (3)

(57) [Claims] 1. A one-component developer to which an auxiliary agent is externally added as required, and a developer carrier for carrying the developer on a surface thereof and transporting the developer to a development area by moving the surface. A one-component developing device configured to seal the developer by a longitudinal end of the developer carrier being in contact with a side plate of a developer container via a seal member, comprising: A bristle-brush-shaped member is provided on a surface of the seal member facing the longitudinal end of the developer carrier, and the length of the bristle brush is longer on the downstream side than on the upstream side in the surface movement direction of the developer carrier. A one-component developing apparatus wherein the seal member is set so as to increase the developer sealing property from the upstream side to the downstream side in the surface moving direction of the developer carrier. 2. A one-component developer to which an auxiliary agent is externally added as required, and a developer carrier for carrying the developer on a surface thereof and transporting the developer to a development area by moving the surface. A one-component developing device configured to seal the developer by a longitudinal end of the developer carrier being in contact with a side plate of a developer container via a seal member, comprising: A bristle-brush-shaped member is provided on a surface of the seal member facing the longitudinal end of the developer carrier, and the density of the bristle is higher on the downstream side than on the upstream side in the surface movement direction of the developer carrier. The one-component developing device according to claim 1, wherein the developer sealing property of the seal member is increased from the upstream side to the downstream side in the surface moving direction of the developer carrier. 3. A one-component developer to which an auxiliary agent is externally added as required, and a developer carrier for carrying the developer on a surface and transporting the developer to a development area by moving the surface. A dielectric portion for retaining charges and a grounded conductive portion are exposed on the surface of the developer carrying member, and a large number of minute closed electric fields are formed by the dielectric portion and the conductive portion. To form
A one-component developing device for visualizing an electrostatic latent image by holding the developer in multiple layers on the surface of the developer carrier by the minute closed electric field, the developer carrier corresponding to a non-image area In the longitudinal end portion, the minute closed electric field is weakened or eliminated from the longitudinal central portion of the developer carrier corresponding to the image region, and the small closed electric field corresponds to the non-image region. A one-component developing device, wherein a charge removing member for removing a charge held by the dielectric portion provided at the end of the developer carrier is provided at a longitudinal end of the developer carrier.