JP3330765B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
More specifically, the present invention relates to an apparatus for collecting toner when a two-component developer is used.

[0002]

2. Description of the Related Art Some image forming apparatuses such as copiers, printers and facsimile machines use an electrophotographic copying system. In the electrophotographic copying method, an electrostatic latent image is formed on a photosensitive member serving as a uniformly charged image carrier by exposure or optical writing, and this electrostatic latent image is mixed with, for example, a magnetic carrier and a toner. When a two-component developer is used, an image subjected to visible image processing with toner is transferred to a recording paper or the like to obtain a copy. Ideally, all of the toner used for visible image processing is transferred to recording paper, but in practice, a part of the toner may remain on the photoconductor. Conventionally, a cleaning step has been provided to remove such residual toner. In this step, the residual toner is mechanically scraped off using a blade or a brush member that contacts the surface of the photoconductor. Was.

[0003] Toner scraped off from the photoreceptor (hereinafter, referred to as
At present, waste toner is stored in a collection tank or the like and is disposed of. However, in recent years, there has been a demand for saving resources. Is required.

In view of the above, conventionally, there has been proposed a configuration in which the toner once removed from the photosensitive member in the cleaning step is returned to the developing unit and reused (for example, Japanese Patent Application Laid-Open Nos. 60-51876 and 60-51876). JP-A-60-156081, JP-A-2-12280, JP-A-2-236
575).

[0005]

The waste toner removed from the photoreceptor in the cleaning step is
Due to the influence of the transfer bias applied in the transfer process, the charging polarity may be reversed from the polarity held at the time of frictional charging, so-called positive and negative polarities,
There are foreign matters such as paper dust mixed in, and when used in the visible image processing of the electrostatic latent image as it is returned to the developing device, only unused toner is used without using waste toner. There is a problem that the image density of the visible image is different as compared with the case where the image is displayed.

On the other hand, in a developing device using a two-component developer, the toner is agitated and frictionally charged, and the toner must be electrostatically adsorbed to a carrier. Since a space for stirring and mixing the toner and the carrier is required, the size of the developing device tends to be larger than that of a developing device using a one-component developer.

[0007] Under such circumstances, if the waste toner is stirred and mixed with the unused toner to maintain a constant mixing ratio, it is possible to prevent the image density from changing. At present, it cannot be denied that the size has been increased.

An object of the present invention is to solve the above-mentioned problem relating to the recovery of residual toner in the conventional image forming apparatus, and it is necessary to collect waste toner and use it again for visible image processing without increasing the size of the structure. It is an object of the present invention to provide an image forming apparatus having a waste toner collecting structure capable of always stabilizing a mixing ratio with a used toner and preventing an image density from changing.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a two-component developer containing a toner to be brought into contact with an electrostatic latent image on an image carrier is supported on the surface. A developer carrying member, and a developing device equipped with the developer carrying member for transferring toner remaining on the image carrier after an image subjected to visible image processing on the image carrier is transferred. And a recovery unit for returning the toner to the developer carrying member. The developing device is capable of storing unused toner along the moving direction of the developer carrying member, and A toner storage unit having a member for scraping unused toner, and a doctor member and a surplus developer other than the specified amount are defined behind the toner storage unit. The above developer carrying member table And a toner stagnation section having a space that can be circulated away from the toner storage section, and an end of the recovery section is communicated with the developer circulation space in the toner stagnation section. Features.

According to a second aspect of the present invention, there is provided a developer carrying member having on its surface a two-component developer containing a toner to be brought into contact with an electrostatic latent image on an image carrying member; A recovery unit for returning the toner remaining on the image carrier to a developing device equipped with the developer carrying member after the image subjected to the visible image processing is transferred; In the developing device, the developing device is disposed behind a supply position of the toner to the image carrier along the moving direction of the developer carrying member, and supplies the developer carried by the developer carrying member. A toner holding section provided with a space for circulating and stirring and a stirring member is provided, and the toner holding section is disposed behind the toner holding section in the moving direction of the developer carrying member, and can store unused toner. With the above development And a toner accommodating portion provided with a member for scraping the fresh toner toward the bearing member, the ends of the collecting portion is disposed in the movement trajectory vicinity of the stirring portion <br/> member provided in the toner holding portion It is characterized by being.

According to a third aspect of the present invention, there is provided a developer carrying member having on its surface a two-component developer containing toner to be brought into contact with an electrostatic latent image on an image carrier, and A recovery unit for returning the toner remaining on the image carrier to a developing device equipped with the developer carrying member after the image subjected to the visible image processing is transferred; In the developing device, the developing device is disposed behind a supply position of the toner to the image carrier along the moving direction of the developer carrying member, and supplies the developer carried by the developer carrying member. A toner holding section provided with a space for circulating and stirring and a stirring member is provided, and the toner holding section is disposed behind the toner holding section in the moving direction of the developer carrying member, and can store unused toner. With the above development A toner accommodating portion provided with a member for scraping the fresh toner toward the bearing member, the toner accommodating portion
A developer that is located rearward and is carried by the developer carrying member
Other than the doctor member and the specified amount
The excess developer away from the developer carrying member surface
Toner stagnant that forms a space that can be circulated
And the end of the collection unit is located in or on the path of the stirring member provided in the toner storage unit.
At least one of the developer circulating spaces in the toner stagnation section.
It is characterized in that in communication. According to a fourth aspect of the present invention, there is provided a developer carrying member having on its surface a two-component developer containing a toner to be brought into contact with an electrostatic latent image on an image carrier, and a visible image on the image carrier. A transfer unit for returning the toner remaining on the image carrier to a developing device equipped with the developer carrying member after the processed image is transferred; The developing device is disposed behind the position where the toner is supplied to the image carrier along the moving direction of the developer carrying member, and takes in the developer carried by the developer carrying member and circulates the developer. A toner holding section provided with a space for stirring and a stirring member, and a toner holding section disposed behind the toner holding section in the direction of movement of the developer carrying member, capable of storing unused toner and For developer carrying member A toner container having a member for scraping the unused toner, and a doctor member which is located behind the toner container and regulates the amount of developer carried on the developer carrying member, and a doctor member other than the prescribed carrying amount. And a toner stagnation section having a space in which the excess developer can be separated from the surface of the developer carrying member and circulated, and an end of the recovery section is provided in the toner storage section. G
Communicating with the vicinity of the movement trajectory of the
At least one of the trajectories of the stirring member provided in the toner storing section or the developer circulating space of the toner storing section.
It is characterized in that in communication with the person.

[0012]

According to the first aspect of the present invention, the waste toner removed from the image carrier in the cleaning step is mixed with the excess developer circulating in the toner retaining section and stirred.

According to the second aspect of the present invention, the waste toner removed from the image carrier in the cleaning step is a toner.
The developer is dropped into the movement locus of the agitating member in the holding unit, and is placed on the developer holding member taken into the toner holding unit.
And mixed with the developer .

According to the third aspect of the present invention, special stirring and mixing are performed.
Developer or unused toner without using
And waste toner are agitated and mixed.

According to the fourth aspect of the invention, the developer or unused toner and the waste toner are stirred and mixed without using a special stirring and mixing member.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is a cross-sectional view showing a main structure of a developing device used in the image forming apparatus of the present invention.

In FIG. 1, a developing device 1 is provided at a position corresponding to a position after an electrostatic latent image is formed in a moving direction of a photoreceptor as an image carrier, similarly to the type used in the electrophotographic copying system. ing. The developing device 1 includes a unit that rotatably supports a developing sleeve 2 that is a developer carrying member. In the developing device 1 composed of a unit, a toner stagnation unit 3, a toner storage unit 4, and a toner storage unit 5 are formed in order from the downstream side in the moving direction of the developing sleeve 2, that is, in the rotation direction. I have.

The toner stagnation section 3 is a section for defining the layer thickness of the developer carried on the developing sleeve 2, and is a doctor blade 3 A close to the peripheral surface of the developing sleeve 2.
And a circulation space 3B in which surplus developer other than the amount specified by the doctor blade 3A is pushed back by the doctor blade 3A. This circulation space 3B
The surplus developer moves in the direction opposite to the rotation direction of the developing sleeve 2 as shown by an arrow A in FIG. 1 by being blocked and pushed back by the doctor blade 3A, In FIG. 1, the space is circulated by moving toward the doctor blade 3A along the moving direction of the developing sleeve 2 as indicated by an arrow B. In the circulation space 3B, the excess developer is transferred to the doctor blade 3A.
What is blocked and pushed back by the developer drops and mixes into the developer carried on the developing sleeve 2, and circulates by moving toward the doctor blade 3 </ b> A again along with the rotation of the developing sleeve 2. Will be. As a result, the surplus developer is subjected to frictional charging of the toner in the course of circulation.

The toner storage section 4 is a space separated from the toner storage section 3 by a partition wall 6 provided between the toner storage section 3 and the toner storage section 3. The toner storage section 4 can store unused toner.
At a position facing the developing sleeve 2 in that space,
An opening 4A for scraping unused toner toward the developing sleeve 2 is formed.

An agitator 7 corresponding to a rotatable scraping member is disposed inside the toner container 4.
The agitator 7 can be rotated intermittently or continuously by a drive motor (not shown).

The end of the partition wall 6 facing the developing sleeve 2 is 0.3 to 2.0
A flat portion 6A having a gap of about mm and having the same curvature as that of the developing sleeve 2 is formed.
The flat plate portion 6A causes the developer to rub against each other when the developer mixed with the unused toner and the carrier scraped out of the toner storage portion 4 moves with the rotation of the developing sleeve 2. It is a place where frictional charging is performed. If the gap is too small, the developer tends to cause blocking, which causes a problem that the rotational torque of the developing sleeve 2 increases. If the gap is too wide, the degree of friction between the developers decreases. As a result, the frictional charging of the toner cannot be performed satisfactorily, and the toner is scattered to cause the background of the photoconductor to be stained.

The toner retaining section 5 takes in the residual developer from the surface of the developing sleeve 2 on which the visible image processing of the electrostatic latent image on the photosensitive member is completed, and agitates and mixes the taken-in developer. This is the circulation / stirring part for sending out to An opening 5A is formed in the toner holding section 5 on the side facing the developing sleeve 2, and magnetic bodies 8 and 9 are provided on the inner surface of the lower wall and the inner surface of the upper wall of the opening 5A. Of these magnetic bodies 8 and 9,
The magnetic material 8 provided on the lower wall corresponding to the rear side in the rotation direction easily transfers the residual developer into the toner storage unit 5 by the magnetic force in addition to the gravity of the residual developer carried on the developing sleeve 2. The magnetic body 9 provided on the upper wall corresponding to the front side in the rotation direction of the developing sleeve 2 is located at a position facing the magnetic body 9 inside the developing sleeve 2. In cooperation with the magnetic material 10 provided, blocking of the developer is generated, and the unused toner scraped out of the toner storage unit 4 is blocked so as not to excessively enter the toner storage unit 5. ing. For this reason, the magnetic body 9 on the toner storage section 5 side and the magnetic body 10 on the developing sleeve 2 side are set to have a relationship of opposite polarities, whereby concentrated magnetization occurs between the magnetic bodies. ing.

Agitators 11 rotatable in the direction in which the taken-in residual developer can be sent out toward the developing sleeve 2 are provided in the interior of the toner storing section 5 in proximity to the magnetic members 8 and 9. . The agitator 11 is a magnetic material 8
The residual developer taken in from the magnetic material 8 can be scraped off from the magnetic material 8 and retained inside, and the retained residual developer is agitated to promote the triboelectric charging of the toner. The developer that has been agitated is delivered toward the developing sleeve 2 when the delivery direction coincides with the developing direction.

The recovery unit for collecting the waste toner removed from the surface of the photoconductor by cleaning the photoconductor is connected to the developing device 1 having the above-described configuration.

FIG. 2 is a sectional view showing an embodiment of the first aspect of the present invention. In this embodiment, the end 12A of the collection pipe 12 forming a part of the collection section is excessively developed in the toner accumulation section 3. The agent is connected to a circulation space 3B corresponding to a region where the agent is pushed back by the doctor blade 3A. The end 12A of the recovery pipe 12 is inserted in parallel with the axial direction of the developing sleeve 2 from the opening 3C formed in the side wall of the toner retaining section 3 toward the inside of the circulation space 3B. A rotatable transport screw (not shown) is arranged inside the recovery pipe 12, and the developer is transported by the transport screw. An opening (not shown) is formed in the end 12 </ b> A of the collection pipe 12 in a range where the end is inserted into the toner storage unit 3, and the end 12 </ b> A is uniformly formed in the toner storage unit 3 along the axial direction of the developing sleeve 2. The waste toner can be dropped.

Since the present embodiment has the above configuration,
From the end 12A of the collection pipe 12, the waste toner falls into the circulation space 3B of the toner stagnation section 3. The waste toner that has dropped into the circulation space 3B is mixed with the developer that is blocked and pushed back by the doctor blade 3A in the circulation space 3B, and can be circulated together with the developer. As a result, the waste toner is frictionally charged by being stirred and mixed with the development.

According to the present embodiment, the doctor blade 3A
Since the developer, which is blocked and pushed back by itself, can be stirred and mixed by circulating, the need for a special stirring structure is eliminated.

FIG. 3 is a cross-sectional view showing an example of the prior art . In this example , the end 12A of the recovery pipe 12 is located near the rotation locus of the agitator 7 provided in the toner storage section 4. is there. In shown to Example 3, in order to allow the free fall of the waste toner, (in FIG. 3, the locus indicated by a one-dot chain line) rotation locus of the agitator 7 collection pipe 1 above and in the vicinity of
Two ends 12A are arranged. Terminal 12 in this case
2A, similarly to the embodiment shown in FIG. 2, is inserted into the toner accommodating portion 4 in parallel with the axial direction of the developing sleeve 2, and has an opening for dropping waste toner.

Since the conventional example has the above configuration,
Waste toner falls from the end 12 </ b> A of the collection pipe 12 into the toner storage unit 4 and enters the rotation locus of the agitator 7. The waste toner that has entered the rotation locus of the agitator 7 is stirred and mixed with the unused toner by the rotation of the agitator 7 and is frictionally charged, and the charged charge is equalized with the unused toner.

According to this conventional example, it is possible to mix the waste toner and the unused toner only by using the agitator corresponding to the scraping member of the unused toner which is an existing member. As a result, the collected waste toner is inevitably mixed with unused toner without requiring any special mixing means.

FIG. 4 is a sectional view showing an embodiment of the second aspect of the present invention. In this embodiment, the end 12A of the recovery pipe 12 is rotated by the agitator 11 mounted on the toner storing section 5. It is located nearby. In the embodiment shown in FIG. 4, the rotation locus of the agitator 11 (the locus indicated by a chain line in FIG. 4) in order to enable the free fall of the waste toner.
The end 12A of the recovery pipe 12 is arranged near the upper part of the collection pipe 12. In this case, similarly to the embodiment shown in FIG. 2, the end 12A is inserted into the toner accommodating portion 4 in parallel with the axial direction of the developing sleeve 2, and an opening for dropping waste toner is formed. .

Since the present embodiment has the above configuration,
Waste toner falls from the end 12 </ b> A of the collection pipe 12 into the toner storage unit 5 and enters the rotation locus of the agitator 11. The waste toner that has entered the rotation trajectory of the agitator 11 is stirred and mixed with the residual developer taken in from the developing sleeve 2 by the rotation of the agitator 11 and frictionally charged, and the charged charge is equalized with the toner in the developer. Is done.

According to this embodiment, it is possible to mix the waste toner and the residual developer taken in from the developing sleeve and enhancing the triboelectric charging simply by using the agitator corresponding to the stirring member which is an existing member. Will be possible. Thus, the collected waste toner is necessarily mixed with the residual developer without requiring any special mixing means.

FIG. 5 is a sectional view showing an embodiment of the present invention according to claims 3 and 4. In this embodiment, the end 12A of the recovery pipe 12 is located within the circulation space 3B in the toner retaining section 3. The toner storage unit 5 is located at any position near the rotation locus of the agitator 11. FIG.
In the embodiment shown in (1), the end of the recovery pipe 12 is branched and positioned at each of the above-mentioned portions. In this case, similarly to the embodiment shown in FIG. 2, the end 12A is inserted into the toner accommodating portion 4 in parallel with the axial direction of the developing sleeve 2, and an opening for dropping waste toner is formed. .

Since the present embodiment has the above configuration,
From the end 12A of the recovery pipe 12, the waste toner enters the circulation locus 3B of the toner stagnation section 3, the rotation locus of the agitator 7 in the toner storage section, and the rotation locus of the agitator 11 in the toner storage section 5.

The waste toner that has entered the circulation space 3B in the toner retaining section 3 is mixed with the developer in the circulation space 3B as in the embodiment shown in FIG. The waste toner that has entered the rotation locus of the agitator 7 in the unit 4 is mixed with the unused toner, and the waste toner that has entered the rotation locus of the agitator 11 in the toner storage unit 5 is developed by the developing sleeve 2. Mixed with the agent. In the embodiment that is shown in FIG. 5 toner retention part 3, in any of the toner containing portion 4 and the toner storage section 5 is a configuration for feeding waste toner, toner
Needless to say, the waste toner may be fed into at least one of the staying section 3 and the toner storing section 5 and mixed and stirred.

[0038]

As described above, according to the first aspect of the present invention, the waste toner removed from the image carrier in the cleaning step is contained in the surplus developer circulating in the toner accumulation section. Since they are mixed and stirred, it is possible to equalize the dispersion state of the waste toner in the developer without requiring a special stirring and mixing structure.

[0039] According to the second aspect of the invention, the waste toner removed from the image bearing member by a cleaning step, enters and falls during the movement locus of the agitating member in the toner holding section, taken in the toner holding portion Developer carrying part
Since mixed into the developer from the timber is agitated, the developer responsible
After being taken in from the holding member and promoting triboelectric charging,
The stirring and mixing with the developer fed to the developer carrying member is carried out only by using the existing components.
The mixing ratio of waste toner in the developer can be stabilized.

According to the third aspect of the invention, special stirring is performed.
Without using a mixing member, the developer or unused toner
The toner and the waste toner are agitated and mixed.
Configuration to stabilize the mixing ratio of
Can be used and uniform waste toner without increasing the size of the structure.
It is possible to set the mixing ratio of the colors.

According to the fourth aspect of the present invention, since the developer or unused toner and the waste toner are stirred and mixed without using a special stirring and mixing member, the mixing ratio of the Hiki toner is stabilized. Can be simplified, and a uniform mixing ratio of waste toner can be set without increasing the size of the structure.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a developing device used in an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining a main configuration of a developing device used in the image forming apparatus shown in FIG.

3 is a cross-sectional view for explaining an example of the prior art.

FIG. 4 is a cross-sectional view for explaining another example of a main configuration of a developing device used in the image forming apparatus shown in FIG.

FIG. 5 is a cross-sectional view for explaining still another example of the configuration of the main part of the developing device used in the image forming apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2 Developing sleeve which is a developer carrier 3 Toner retaining portion 3A Doctor blade 3B Circulating space 4 Toner accommodating portion 4A Toner scraping opening 5 Toner retaining portion 7 Agitator as scraping member 11 Agitator as stirring member

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI G03G 21/00 326 (72) Inventor Fumihiro Sasaki 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72 Inventor Hidefumi Gohara 1-3-6 Nakamagome, Ota-ku, Tokyo; Examiner at Ricoh Company, Ltd. Yusuke Takahashi (56) References JP-A-61-258276 (JP, A) JP-A-4 -283777 (JP, A) JP-A-6-258987 (JP, A) JP-A-6-342240 (JP, A) JP-A-6-118791 (JP, A) (58) Fields investigated (Int. . ^7, DB name) G03G 13/08 - 13/095 G03G 15/08 - 15/095

Claims (4)

(57) [Claims] A developer carrying member carrying a two-component developer containing a toner to be brought into contact with an electrostatic latent image on the image carrier; and a visible image processing device on the image carrier. A collecting unit for returning the toner remaining on the image carrier to the developing device equipped with the developer carrying member after the image is transferred, wherein the developing device comprises: A toner accommodating section which is capable of accommodating unused toner along the moving direction of the developer carrying member and has a member for scraping the unused toner toward the developer carrying member; A doctor member that regulates the amount of developer carried on the developer carrying member and a space that allows excess developer other than the prescribed carrying amount to circulate away from the surface of the developer carrying member are formed. Tona being An image forming apparatus, comprising: a stagnation section; and an end of the collection section is communicated with a space for circulating the developer in the toner stagnation section. 2. A developer carrying member having on its surface a two-component developer containing a toner to be brought into contact with an electrostatic latent image on an image carrier, and a visible image processed on the image carrier. A collecting unit for returning the toner remaining on the image carrier to the developing device equipped with the developer carrying member after the image is transferred, wherein the developing device comprises: Along the moving direction of the developer carrying member, the developer carrying member is disposed behind the toner supply position to the image carrier, takes in the developer carried by the developer carrying member, and circulates and agitates the developer. A toner holding section provided with a space for performing the stirring and a stirring member; and a toner holding section disposed behind the toner holding section in the moving direction of the developer holding member, capable of storing unused toner, and Above And a toner accommodating portion provided with a member for scraping a used toner, the ends of the collecting part, the image forming apparatus characterized by being arranged in the movement locus vicinity of the stirring member provided in the toner holding portion 3. A developer carrying member having on its surface a two-component developer containing a toner to be brought into contact with an electrostatic latent image on an image carrier, and a visible image processed on the image carrier. A collecting unit for returning the toner remaining on the image carrier to the developing device equipped with the developer carrying member after the image is transferred, wherein the developing device comprises: Along the moving direction of the developer carrying member, the developer carrying member is disposed behind the toner supply position to the image carrier, takes in the developer carried by the developer carrying member, and circulates and agitates the developer. A toner holding section provided with a space for performing the stirring and a stirring member; and a toner holding section disposed behind the toner holding section in the moving direction of the developer holding member, capable of storing unused toner, and Above A toner storage unit having a member for scraping the used toner, and a toner storage unit located behind the toner storage unit;
Defines the amount of developer carried on the developer carrying member
And the excess developer other than the specified amount
Circulating away from the surface of the developer carrying member
And the toner stagnation area where a space is formed
Are provided, the ends of the collecting portion, in the trajectory of the stirring member provided in the toner storing portion or the toner retention part of the developer
An image forming apparatus communicating with at least one of the circulation spaces . 4. A developer carrying member having on its surface a two-component developer containing a toner to be brought into contact with an electrostatic latent image on an image carrier, and a visible image processed on the image carrier. A collecting unit for returning the toner remaining on the image carrier to the developing device equipped with the developer carrying member after the image is transferred, wherein the developing device comprises: Along the moving direction of the developer carrying member, the developer carrying member is disposed behind the toner supply position to the image carrier, takes in the developer carried by the developer carrying member, and circulates and agitates the developer. A toner holding section provided with a space for performing the stirring and a stirring member; and a toner holding section disposed behind the toner holding section in the moving direction of the developer holding member, capable of storing unused toner, and Above A toner storage unit having a member for scraping the used toner, and a toner storage unit located behind the toner storage unit;
A space is formed in which a doctor member that regulates the amount of developer carried on the developer carrying member and a surplus developer other than the prescribed carrying amount can be circulated away from the surface of the developer carrying member. And an end of the collection unit is provided in the toner storage unit.
Around the movement locus of the toner scraping member, and
In the trajectory of the stirring member provided in the toner holding section,
Alternatively, the image forming apparatus communicates with at least one of the developer circulating spaces in the toner stagnation section.