Developer supply container and image forming apparatus capable of mounting the container thereon

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a developer supply container useable in a copying machine, a printer or the like and an image forming apparatus capable of mounting the container thereon.

2. Related Background Art

As an image forming apparatus for forming an image on a recording medium using, for example, an electrophotographic image forming process as a recording technology, a copying machine, a printer (a laser beam printer, an LED printer or the like), a facsimile machine, a wordprocessor and the like have been proposed. Conventionally, fine powder toner has been used as a developer for such an image forming apparatus. When toner is consumed, a developer supply container is used to supply toner to a developing device.

Here, since toner is an extremely fine powder, it is necessary to configure an image forming apparatus such that toner does not scatter during operations for supplying toner. Thus, there is known a process of installing a developer supply container in the apparatus and discharging toner little-by-little from an outlet or a small opening provided in the developer supply container to a supply port of a developing device. In discharging toner in this way, since it is difficult for toner to be discharged automatically by the force of gravity, some toner feeding means is necessary.

Such a process is capable of supplying toner just enough and maintaining an amount of toner constant in a developing device. It is also effective, in particular, for maintaining a ratio of mixing a carrier component and a toner component always at a constant level if a two-component developer is used.

As described above, a so-called stationary developer supply container is effective for stabilizing levels of a discharge amount of toner and a ratio of mixing a carrier component and a toner component in a two-component developer. However, as a quality of an image has been getting higher in an electrophotographic image forming apparatus in recent years, there are more serious needs for stabilizing the level of the mixing ratio.

In order to stabilize the levels of the discharge amount and the mixing ratio, it is important to realize how to stabilize an amount of toner discharged from the outlet from the time when the developer supply container is sufficiently filled with a developer to the time when the developer supply container becomes almost empty.

In addition, since toner is a fine powder, it is necessary to seal a combining part between containers such that the toner does not leak. However, it is almost impossible to perfectly prevent the toner from leaking out of the combining part due to an effect of vibration or the like at the time when a container is attached or detached no matter how the combined part is sealed. Thus, it is desirable to reduce the number of parts requiring sealing, such as a combining part between containers, as much as possible.

SUMMARY OF THE INVENTION

The present invention has been devised in view of the above problems, and it is an object of the present invention to provide a developer supply container that always supply a stabilized amount of a developer and an image forming apparatus capable of mounting the container thereon.

It is another object of the present invention to provide a developer supply container capable of reducing sealing parts and an image forming apparatus capable of mounting the container thereon.

It is another object of the present invention to provide a developer supply container that includes:

a containing chamber for containing a developer;

a first feeding member, which is provided in the containing chamber and which feeds the developer to an outlet of the containing chamber;

a feeding chamber communicating with the containing chamber;

a second feeding member, which is provided in the feeding chamber and which feeds the developer coming from the containing chamber to an outlet of the container;

a partition member for partitioning said developer supply container into said containing chamber and said feeding chamber,

wherein a partitioning area of said partition member is much larger than an area of said outlet of said containing chamber.

It is yet another object of the present invention to provide an image forming apparatus that includes:

developing means for developing a latent image formed on an image bearing member; and

a developer supply container for supplying developer to the developing means, the developer supply container being detachably mountable to the image forming apparatus, wherein the developer container includes:

a containing chamber for containing a developer;

a first feeding member, which is provided in the containing chamber and which feeds the developer to an outlet of the containing chamber;

a feeding chamber communicating with the containing chamber;

a second feeding member, which is provided in the feeding chamber and which feeds the developer coming from the containing chamber to an outlet of the container;

a partition member for partitioning said developer supply container into said containing chamber and said feeding chamber,

wherein a partitioning area of said partition member is much larger than an area of said outlet of said containing chamber.

Other objects, features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is an external perspective view of an image forming apparatus in accordance with the present invention;

FIG. 2

is an overall view of the image forming apparatus;

FIG. 3

illustrates a configuration of a process cartridge;

FIG. 4

is a vertical sectional view of a developer supply container;

FIG. 5

is an external perspective view of the developer supply container;

FIG. 6

illustrates a state in which the developer supply container is mounted on the process cartridge;

FIG. 7

is a longitudinal sectional view of the developer supply container;

FIG. 8

is an enlarged view of the vicinity of an outlet;

FIG. 9

is a longitudinal sectional view of the process partridge;

FIG. 10

illustrates a state in which a toner containing portion

52

is sufficiently filled with toner;

FIG. 11

illustrates a state in which the toner in the toner containing portion

52

decreases;

FIG. 12

illustrates a state in which the toner in the toner containing portion

52

is running out; and

FIG. 13

is a longitudinal sectional view of a developer supply container in accordance with another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of a developer supply container and an image forming apparatus in accordance with the present invention will be described with reference to the drawings.

FIG. 1

is an external perspective view of an image forming apparatus in accordance with this embodiment,

FIG. 2

is an overall view of the image forming apparatus in accordance with this embodiment,

FIG. 3

illustrates a configuration of a process cartridge,

FIG. 4

is a vertical sectional view of a developer supply container,

FIG. 5

is an external perspective view of the developer supply container,

FIG. 6

illustrates a state in which the developer supply container is mounted on the process cartridge,

FIG. 7

is a longitudinal sectional view of the developer supply container,

FIG. 8

is an enlarged view of the vicinity of an outlet,

FIG. 9

is a longitudinal sectional view of the process cartridge, and

FIGS. 10

to

12

illustrate how a developer is consumed.

In this embodiment, an image forming apparatus will be described referring to a color electrophotographic image forming apparatus as an example. Incidentally, in the following descriptions, a longitudinal direction means a direction in which a process cartridge

3

is inserted in an apparatus main body and which crosses (is substantially perpendicular to) a transporting direction of a recording medium P. This direction is the same as an axial direction of a photosensitive drum

4

, or an image bearing member. In addition, left and right mean left and right viewed from the transporting direction of the recording medium P. Moreover, an upper part and a lower part mean an upper part and a lower part in a state in which the process cartridge

3

is mounted.

(Overall Configuration)

An overall configuration of an image forming apparatus will be described first with reference to FIG.

2

. An image forming apparatus

1

shown in

FIG. 2

has four process cartridges

3

(

3

Y,

3

M,

3

C and

3

K) provided with a drum shaped electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum), or an image bearing member. Laser exposing means

2

(

2

Y,

2

M,

2

C and

2

K) of colors corresponding to the process cartridges

3

, respectively, are arranged in parallel above the process cartridges

3

. Toner is supplied to the process cartridges

3

by toner supply containers

50

(

50

Y,

50

M,

50

C and

50

K) or developer supply containers to be described later, and toner images or developer images are formed on the photosensitive drum

4

. The formed toner images are superimposed to be transferred on an intermediate transfer belt

28

.

Sheet transporting means

35

for transporting the recording medium P is disposed below the image forming apparatus. The sheet transporting means

35

transports the recording medium P so that the toner images on the intermediate transfer belt

28

are collectively transferred on the recording medium P. Thereafter, a fixing device

43

fixes the toner images and then the recording medium P is delivered to the outside of the apparatus. Here, the recording medium P is, for example, a sheet of paper, an OHP sheet and a cloth. The image forming apparatus in this embodiment is a cleaner-less system, which collects transfer residual toner left on the photosensitive drum

4

in developing means

6

, and a cleaner for collecting and storing the transfer residual toner is not disposed in the process cartridge

3

.

In addition, in this embodiment, a developer is a two-component developer in which a toner component and a carrier component are mixed. Negative chargeable toner with an average particle diameter of 6 μm is used as toner, and a magnetic carrier with a saturation magnetization of 205 emu/cm

3

and an average particle diameter of 35 μm is used as a magnetic carrier. In addition, a mixture of a toner component and a carrier component mixed at a weight ratio of 6:94 is used as a developer. A configuration of each part of the image forming apparatus will be hereinafter described sequentially.

(Process Cartridge)

The process cartridges

3

Y,

3

M,

3

C and

3

K (yellow, magenta, cyan and black) are integrally formed with charging means

5

and developing means

6

arranged around the photosensitive drum

4

as shown in

FIG. 3. A

user can easily attach and detach these process cartridges

3

to and from an image forming apparatus main body (hereinafter simply referred to as an apparatus main body

1

), and replace them when the photosensitive drum

4

has run down. For example, in this embodiment, the number of rotations of the photosensitive drum

4

is counted, and when the number of rotations exceeds a predetermined count, a user is informed that a process cartridge has run down.

The photosensitive drum

4

in accordance with this embodiment is a negative chargeable organic photoconductor, has a photoconductive layer, which is usually used, on a drum substrate of aluminum with a diameter of approximately 30 mm, and is provided with a charge injection layer as a top layer. The photosensitive drum

4

is rotated to be driven at a predetermined process speed, at approximately 117 mm/sec in this embodiment. The charge injection layer uses a coating layer of a material in which, for example, SnO

2

ultra-fine particles are dispersed as conductive fine particles in a binder of insulating resin.

A drum flange

4

b

is fixed in a deep end part of the photosensitive drum

4

(see FIG.

9

), and a driven flange

4

d

is fixed in a front end part. The centers of the drum flange

4

b

and the driven flange

4

d

are penetrated by a drum shaft

4

a

, and the drum shaft

4

a

, the drum flange

4

b

and the driven flange

4

d

are integrally rotated. That is, the photosensitive drum

4

is rotated around the drum shaft

4

. The front end part of the drum shaft

4

a

is rotatably supported by a bearing

4

e

, which is fixed to a bearing case

4

c

. The bearing case

4

c

is fixed to a frame

3

a

of the process cartridge

3

.

(Charging Means)

The charging means in accordance with this embodiment employs a contact charging method, and employs a magnetic brush charging device

7

using magnetic particles as a charging member. More specifically, a magnetic brush portion is formed by magnetically binding conductive magnetic particles as a charging member, the magnetic brush portion is brought into contact with the photosensitive drum

4

and a voltage is applied to the magnetic brush portion, whereby a photoconductor is charged.

Such a charging method (charging of a charged body by direct injection of charge) is referred to as an injection charging process. With this injection charging process, a cleaner mechanism (a cleaning blade, a cleaning roller or the like) for mechanically scraping off and removing transfer residual toner on the photosensitive drum

4

becomes unnecessary. This cleaner-less system will be described later. In addition, the injection charging process of this embodiment does not utilize a discharge phenomenon in which charging to a charged body is performed using a corona charger. Thus, an applied charge bias required for charging is a bias only in the amount of a desired surface potential of a member to be charged. In addition, the process is perfect ozone-less with no generation of ozone and is low-power consumption charging.

The magnetic brush charging device

7

of this embodiment will now be described in detail with reference to FIG.

3

. In the magnetic brush charging device

7

, a magnetic brush portion of magnetic particles is formed on a charging sleeve

9

enclosing a magnet roller

10

, and the photosensitive drum

4

is charged to a predetermined potential at an abutment portion between the photosensitive drum

4

and the magnetic brush portion.

The charging sleeve

9

is disposed in the longitudinal direction over an opening of a charging container

8

containing the magnetic particles with a substantially left half of its circumferential surface protruding outside. An agitating member

13

is disposed in the charging container substantially parallel with the charging sleeve

9

. The agitating member

13

is disposed above the charging sleeve

9

and is rotatably supported between walls in both end parts in the longitudinal direction.

Moderately coarse unevenness is formed on the surface of the charging sleeve

9

in order to satisfactorily transport the magnetic particles. The magnet roller

10

provided inside the charging sleeve

9

is provided with four magnetic poles in the circumference direction. The magnetic roller

10

is fixed such that one magnetic pole opposes it in the direction to the center of the photosensitive drum

4

in order to prevent the magnetic particles from adhering to the photosensitive drum

4

and being carried in accordance with rotation.

A nonmagnetic regulating blade

11

of a plate shape is supported by the charging container

8

via a supporting plate

12

with a predetermined distance apart from the surface of the charging sleeve

9

. When the magnetic particles are held by the magnet roller

10

and carried in a direction indicated by the arrow B by the rotation of the charging sleeve

9

, the magnetic particle is regulated to a predetermined thickness by the regulating blade

11

and forms a magnetic brush portion on the charging sleeve

9

. The charging sleeve

9

is disposed opposite to the photosensitive drum

4

with a predetermined distance apart from it. The charging sleeve

9

allows the magnetic brush portion formed on the charging sleeve

9

to contact the surface of the photosensitive drum

4

and forms a charge nip portion. The width of the charge nip portion affects the charging property of the photosensitive drum

4

. In this embodiment, the distance is adjusted such that the width of the nip portion is approximately 6 mm.

A predetermined charging bias is applied from a not-shown charging bias source to the magnetic brush portion via the charging sleeve

9

. The photosensitive drum

4

is subjected to the contact charging processing to have a predetermined polarity and potential. As the magnetic particles forming the magnetic brush portion, magnetic metal particles such as ferrite and magnetite or particles obtained by binding these magnetic particles with resin can also be used.

The charging sleeve

9

is rotated to be driven in the direction indicated by the arrow B, which is a counter direction with respect to the rotation of the photosensitive drum

4

or a member to be charged in a direction indicated by the arrow A, in the opposing portion by a not-shown motor. In this embodiment, the charging sleeve

9

is rotated at a velocity ratio of V

2

≅1.5×V

1

in the counter direction with respect to a rotational speed V

1

of the photosensitive drum

4

. The faster the relative rotational speed between the photosensitive drum

4

and the magnetic brush portion the more the opportunity of contact increases. Thus, uniformity of charging becomes better, and absorption of transfer residual toner into a magnetic brush tends to be improved.

In addition, a charging brush

14

is disposed upstream of the charging sleeve

9

in the rotating direction of the photosensitive drum

4

and contacts the surface of the photosensitive drum

4

in an inroad amount of approximately 1 mm to apply a predetermined voltage to it. Transfer residual toner on the photosensitive drum

4

is scattered uniformly by this contact of the charging brush

14

. Moreover, a charge elimination is performed so that charging in the next step is performed uniformly.

(Exposing Means)

Exposure on the photosensitive drum

4

, which is uniformly charged as described above, is performed using the laser exposing means

2

Y,

2

M,

2

C and

2

K (laser beam optical scanning systems) in this embodiment. That is, when an image signal is transmitted from the apparatus main body

1

, the uniformly charged surface of the photosensitive drum

4

is subject to scanning exposure of laser beam L modulated in response to this signal (see FIG.

6

). Then, an electrostatic latent image corresponding to image information is selectively formed on the photosensitive drum

4

.

As shown in

FIG. 6

, the laser exposing means

2

(

2

Y,

2

M,

2

C and

2

K) has a not-shown solid laser element, a polygon mirror

2

a

, an imaging lens

2

b

and a reflective mirror

2

c

. When the solid laser element controls on/off of light emission at predetermined timing by a not-shown light emitting signal generator based on the inputted image signal, laser beam L irradiated from the solid laser element is converted into substantially parallel rays by a not-shown collimator lens system and is scanned by the polygon mirror

2

a

rotating at a high speed. Then, the laser beam L is imaged in a spot shape on the photosensitive drum

4

via the imaging lens

2

b

and the reflective mirror

2

c.

In this way, the exposure in a main scanning direction by the laser beam scan and the exposure in a subscanning direction by the photosensitive drum

4

rotating are performed on the photosensitive drum

4

, and an exposure distribution according to an image signal is obtained. That is, a bright section potential with a decayed potential and a dark section potential with an nondecayed surface potential are formed by irradiating and not irradiating the laser beam L. Then, an electrostatic latent image corresponding to image information is formed by a contrast between the bright section potential and the dark section potential.

(Developing Means)

A developing device

15

or developing means is a two-component contact developing device (two-component magnetic brush developing device) and holds a two-component developer consisting of a carrier and toner on a developing sleeve

17

or a developer bearing member incorporating a magnet roller

18

therein. A regulating blade

19

is provided with a predetermined distance apart from the developing sleeve

17

and forms a thin layer developer on the developing sleeve

17

in accordance with the rotation of the developing sleeve

17

in a direction indicated by the arrow C. The regulating blade

19

is fixedly supported by a developing container

16

. The developing sleeve

17

is disposed in parallel with the photosensitive drum

4

with a predetermined distance apart from it. The developing sleeve

17

is set such that development can be performed in the state in which a developer layer formed on the developing sleeve

17

contacts the photosensitive drum

4

at the time of development. The developing sleeve

17

is rotated at a predetermined speed in the direction indicated by the arrow C as a counter direction to the rotational direction of the photosensitive drum

4

in the development portion.

A developer containing portion

20

in which a developer circulates is partitioned into two, except both ends, by a partition wall

21

in the longitudinal direction as shown in

FIGS. 3 and 9

. Agitating screws

22

a

and

22

b

are disposed with this partition wall

21

interposed between them. The agitating screws

22

a

and

22

b

are rotatably supported on both side surfaces of a frame

24

of the process cartridge

3

via a bearing

23

(see FIG.

9

).

A supply port

25

is provided in the upper part of the process cartridge

3

. Toner supplied from a toner supply container

50

to be described later falls in the front side of the agitating screw

22

b

, is fed to the back side in the longitudinal direction while being agitated with a carrier and passes through a part

21

a

in the back side end, which does not have the partition wall

21

. Then, the toner is further transported to the front side in the longitudinal direction by the agitating screw

22

a

, passes through a part

21

b

, not having the partition wall

21

, on the front side and is transported to the agitating screw

22

b

, thereby repeating circulation.

The electrostatic latent image formed on the photosensitive drum

4

will now be described in relation to a developing step, which visualizes the latent image by the two-component magnetic brush method using the developing device

15

, and a circulation system of a developer.

As the developing sleeve

17

rotates, developer in the developing container

16

is drawn to the surface of the developing sleeve

17

by an N3 pole of the magnet roller

18

and transported. In the step of transporting the developer, a layer thickness of the developer is regulated by the regulating blade

19

vertically disposed with respect to the developing sleeve

17

, and a thin layer developer is formed on the developing sleeve

17

. When the thin layer developer is transported to the N1 pole or a developing pole corresponding to the development portion, a magnetic brush is formed by a magnetic force. The latent image on the surface of the photosensitive drum

4

is developed as a toner image by the toner in this developer which stands like the ears of rice. In this embodiment, the electrostatic latent image is reversally developed.

The thin layer developer on the developing sleeve

17

, which has passed through the development portion, continuously enters the developing container

16

in accordance with the rotation of the developing sleeve

17

, leaves the developing sleeve

17

by a repulsive magnetic field between the N2 pole and the N3 pole and is returned to a developer reservoir in the developing container

16

. A direct current (DC) voltage and an alternating current (AC) voltage from a not-shown source are applied to the developing sleeve

17

. In this embodiment, the direct current voltage of −500V and the alternating current voltage being a peak-to-peak voltage of 1,500V at the frequency of 2,000 Hz are applied, whereby development is selectively performed in only exposed part of the photosensitive drum

4

.

Although a development efficiency is improved and a quality of an image becomes higher in general when an alternating current voltage is applied in the two-component development method, a fog tends to be generated to the contrary. Therefore, a fog is usually prevented by generating a potential difference between a direct current voltage applied to the developing sleeve

17

and a surface potential of the photosensitive drum

4

. More specifically, a bias voltage of a potential difference between a potential of an exposed part and an unexposed part of the photosensitive drum

4

is applied. This potential difference for preventing a fog is called a fog removal bias (V back). With this potential difference, toner is prevented from adhering to a nonimage region (unexposed part) on the photosensitive drum

4

at the time of development, and transfer residual toner on the photosensitive drum

4

is also collected in an apparatus of the cleaner-less system (cleaning simultaneous with developing).

When toner is consumed by development, a toner density in a developer decreases. A density detection sensor

26

for detecting a density of toner is disposed in a position adjacent an external circumference surface of the agitating screw

22

b

in this embodiment. When the density detection sensor

26

detects that the density of the toner in the developer becomes lower than a predetermined density level, the density detection sensor

26

orders to supply toner from the toner supply container

50

to the developing device

15

. The toner density of the developer is always maintained at a predetermined level by this toner supplying operation.

(Cleaner-less System)

A cleaner-less system in a reversal development system for negatively charging the photosensitive drum

4

and attaching the negatively charged toner to a low potential part of the exposed part will now be described. In particular, a part of positively charged toner among transfer residual toner, which is left on the photosensitive drum

4

in a small amount after transfer, is electrostatically taken first in the magnetic brush charging device

7

once. The other parts of toner is also collected by forcible scraping using a brush. Then, the toner is charged to a negative polarity by the friction with magnetic particles in the magnetic brush charging device

7

and, then, discharged onto the photosensitive drum

4

.

On the other hand, a part of still negatively charged toner among the transfer residual toner is hardly taken in the magnetic brush charging device

7

and is collected in the developing device

15

together with the foregoing toner discharged from the magnetic brush charging device

7

(cleaning simultaneous with development). This uptake of toner in the developing device

15

in the cleaning simultaneous with development is performed by a fog removal vias (a fog removal potential difference that is a potential difference between a direct current voltage to be applied to the developing device and the surface potential of the photosensitive drum

4

) at the time of development.

According to this method, a part of transfer residual toner is collected in the developing device through the magnetic brush charging device and the rest is directly collected in the developing device to be used in the next step, whereby waste toner is eliminated and labor required for maintenance can be reduced. In addition, as it is cleaner-less, an advantage for a space is large and an image forming apparatus can be miniaturized significantly.

(Transferring Means)

A intermediate transfer unit

27

or transferring means secondarily transfers a plurality of toner images, which are primarily transferred from the photosensitive drum

4

sequentially and superimposed, collectively to a recording medium P. The intermediate transfer unit

27

is provided with an intermediate transfer belt

28

that travels in a direction indicated by the arrow D as shown in

FIG. 2

, and travels at a peripheral speed substantially the same as a peripheral speed of a the photosensitive drum

4

. This intermediate transfer belt

28

is an endless belt with the circumferential length of approximately 940 mm and is looped around a driving roller

29

, a driven roller

30

and a secondary transfer opposed roller

31

.

Moreover, transfer charging rollers

32

Y,

32

M,

32

C and

32

K are rotatably disposed, respectively, in positions opposing the photosensitive drums

4

in the intermediate transfer belt

28

and are pressed in the direction of the center of the photosensitive drum

4

. The transfer charging roller

32

is supplied electricity from a not-shown high voltage source, charged to a polarity opposite the polarity of the toner from the back side of the intermediate transfer belt

28

and primarily transfers the toner images on the photosensitive drum

4

onto the upper surface of the intermediate transfer belt

28

sequentially.

A secondary transfer roller

33

or a transfer member is in pressure contact with a position opposing the secondary transfer opposed roller

31

in the secondary transfer portion. The secondary transfer roller

33

is swingable vertically and rotatable in FIG.

2

. Since a bias is applied to the intermediate transfer belt

28

simultaneously at this point, the toner images on the intermediate transfer belt

28

is transferred to the recording medium P. Further, the intermediate transfer belt

28

and the secondary transfer roller

33

are independently driven, respectively.

When the recording medium P rushes into the secondary transfer portion, a predetermined bias is applied to the secondary transfer roller

33

, and the toner images on the intermediate transfer belt

28

is secondarily transferred to the recording medium P. At this point, the recording medium P that is put between the secondary transfer roller

33

and the intermediate transfer belt

28

is subjected to a transfer step and is transported in the left direction in

FIG. 2

at a predetermined speed, to a fixing device in which the next step is performed.

A cleaning unit

34

, which is separably contactable to the surface of the intermediate transfer belt

28

, is provided in a predetermined position of the intermediate transfer belt

28

that is in the most downstream side of the transfer step. The cleaning unit

34

removes transfer residual toner left on the intermediate transfer belt

28

after the secondary transfer. A cleaning blade

34

a

for removing transfer residual toner is disposed in the cleaning unit

34

. The cleaning unit

34

is swingably attached to a not-shown rotational center and is in pressure contact with the intermediate transfer belt

28

in the direction of cutting into it. The transfer residual toner taken in the cleaning unit

34

is fed to a not-shown waste toner tank by a feeding screw

34

b

and stored therein.

Here, a belt made of polyimide resin can be used as the intermediate transfer belt

28

. Materials for the intermediate transfer belt

28

are not limited to polyimide resin, and plastics such as polycarbonate resin, polyethylene terephthalate resin, polyvinylidene fluoride resin, polyethylene naphthalate resin, polyether ether ketone resin, polyether sulfone resin and polyurethane resin, rubbers of fluorine series and silicon series can be preferably used.

(Sheet Transporting Means)

Sheet transporting means

35

transports the recording medium P to the image forming portion and is composed mainly of a feed cassette

36

in which a plurality of pieces of recording medium P are loaded and contained, a feed roller

37

, a retard roller

38

for double feed protection, a feed guide

39

, a registration roller pair

42

and the like. The feed roller

37

is driven to rotate according to image forming operations and separates to feed the recording medium P in the feed cassette

36

piece-by-piece. The recording medium P is guided by the feed guide

39

and transported to the registration roller pair

42

through transport roller pairs

40

and

41

. The registration roller pair

42

stops its rotation immediately after the recording medium P is transported, and skew feed of the recording medium P is corrected by the recording medium P hitting the nip portion.

The registration roller pair

42

performs a non-rotational operation for allowing the recording medium P to remain stationary and wait and an operation of rotation for transporting the recording medium P toward the intermediate transfer belt

28

in a predetermined sequence. The registration roller pair

42

also performs registration of the toner images and the recording medium P at the time of a transfer step as the next step. Then, when the toner images are transferred on the recording medium P in the secondary transfer portion as described above, the recording medium P is transported to the fixing device by the driving of the intermediate transfer belt

28

and the secondary transfer roller

33

.

(Fixing Device)

A fixing device

43

applies heat and pressure to the toner images transferred on the recording medium P and fixes them on the recording medium P. As shown in

FIG. 2

, the fixing device

43

is provided with a fixing roller

44

for applying heat to the recording medium P and a pressure roller

45

for pressurizing the recording medium P to be contacted with the fixing roller. The fixing roller

44

and the pressure roller

45

are hollow rollers, have not-shown heaters inside, respectively. The fixing roller

44

and the pressure roller

45

are driven to rotate, thereby clamping to transport the recording medium P.

That is, the recording medium P holding the toner images is transported by the fixing roller

44

and the pressure roller

45

and is applied heat and pressure, whereby the toner images are fixed on the recording medium P. The recording medium P after fixing is delivered by delivery rollers

46

and

47

, and is delivered to and loaded in a delivery tray

48

on the apparatus main body

1

.

(Developer Supply Container)

The developer supply container in accordance with the present invention will now be described with reference to

FIGS. 2

,

4

,

5

,

7

,

8

and

9

. Toner supply containers

50

Y,

50

M,

50

C and

50

K or the developer supply containers are disposed in parallel above the process cartridges

3

Y,

3

M,

3

C and

3

K and are configured detachably mountable from the front of the apparatus main body

1

(see FIG.

1

).

The toner supply container

50

has a toner containing portion

52

or a developer containing portion for containing toner inside a frame

51

and a toner feeding portion

54

or a developer feeding portion for feeding toner to an outlet

53

a

as shown in FIG.

4

. The toner containing portion

52

and the toner feeding portion

54

are partitioned by a partition plate

55

that is formed using a sheet member of resin. That is, the -toner supply container

50

has two chambers of the toner containing portion

52

and the toner feeding portion

54

. As shown in

FIG. 7

, the toner containing portion

52

and the toner feeding portion

54

communicate with each other only through a receiving port

55

a

provided at one end of the partition plate

55

.

On the other hand, an agitating plate

57

fixed to an agitating shaft

56

as first feeding means is disposed inside the toner containing portion

52

. A screw

58

or second feeding means is disposed in the toner feeding portion

54

. A discharge opening

53

having an outlet

53

a

for discharging toner is formed on the bottom surface of the toner feeding portion

54

. The screw

58

and the agitating shaft

56

are rotatably supported at their both ends by bearings

59

. Driving couplings (recesses)

60

a

and

60

b

are fixedly disposed in one endmost parts, respectively. The driving couplings (recesses)

60

a

and

60

b

receive the transmission of driving force from driving couplings (protrusions)

61

a

and

61

b

and are driven to rotate by an order sent by the density detection sensor

26

of the developing device

15

.

The agitating plate

57

is formed of a flexible sheet member (e.g., polyethylene terephthalate). A tip of the agitating plate

57

in the rotational radius direction slopes toward the axis (see FIG.

7

), whereby the tip rubs an arc part of the bottom surface of the toner supply container

50

(the bottom surface of the toner containing portion

52

) at a predetermined angle. More specifically, the tip side of the agitating plate

57

is twisted to form a spiral shape. A feeding force of the agitating shaft

56

in the axial direction is generated by the twist and the slope, whereby toner is fed in the longitudinal direction. The slope of the tip of the agitating plate

57

is formed substantially symmetrical around the receiving port

55

a

, whereby the toner in the toner containing portion

52

is fed toward the receiving port

55

a

or a communicating portion with the toner feeding portion

54

. The toner fed to the receiving port

55

a

is forwarded to the toner feeding portion

54

by free fall.

The contour of the screw

58

has a spiral rib shape and reverses the twist direction of the spiral around the discharge opening

53

(see FIG.

8

). Then, the screw

58

is driven by the rotation of the driving coupling (protrusion)

61

b

, thereby feeding the toner toward the discharge opening

53

, causing the toner to fall freely from the outlet

53

a

of the discharge opening

53

, and supplying the toner to the process cartridge

3

via the supply port

25

.

(Mounting the Process Cartridge and the Developer Supply Container)

Attachment and detachment of the process cartridge

3

and the toner supply container

50

will now be described with reference to

FIGS. 1

,

6

,

7

. and

9

. As shown in

FIG. 1

, an open-closeable front door

62

is provided in front of the apparatus main body

1

. When this front door

62

is opened to the front side, openings

1

a

and

1

b

are exposed, in which the process cartridge

3

and the toner supply container

50

are inserted. A rotatably supported centering plate

63

is disposed in the opening

1

b

in which the process cartridge

3

is inserted. The process cartridge

3

is attached and detached after opening and closing the centering plate

63

.

A guide rail

64

for guiding the attachment and detachment of the process cartridge

3

and a guide rail

65

for guiding the mounting of the toner supply container

50

are fixed in the apparatus main body

1

as shown in FIG.

6

. The direction of mounting the process cartridge

3

is parallel with the axial direction of the photosensitive drum

4

. The direction of mounting the toner supply container

50

is parallel with the axial direction of the screw

58

. The guide rails

64

and

65

are disposed in the same directions. The process cartridge

3

and the toner supply container

50

are slid from the front side to the back side of the apparatus main body

1

along the guide rails

64

and

65

once and inserted.

When the process cartridge

3

is inserted in the innermost part, the back side end part of the drum shaft

4

a

is inserted in a centering shaft

66

of the apparatus main body

1

as shown in

FIG. 9

, and the rotational center on the back side of the photosensitive drum

4

is determined with respect to the apparatus main body

1

. In addition, the drum flange

4

b

and the driving coupling (protrusion)

61

c

are coupled simultaneously, thereby enabling the rotational driving of the photosensitive drum

4

. Moreover, a supporting pin

67

a

for positioning the process cartridge

3

on a back side plate id is disposed. The position of the process cartridge

3

is fixed by inserting the supporting pin

67

a

in a recessed part

3

b

provided in the frame

3

a

of the process cartridge

3

. In addition, in the front side of the apparatus main body

1

, a bearing case

4

c

of the photosensitive drum

4

is supported to be fixed by closing the centering plate

63

.

With the series of inserting operations, the process cartridge

3

and the photosensitive drum

4

are positioned with respect to the apparatus main body

1

. That is, the drum shaft

4

a

, the drum flange

4

b

, the recessed part

3

b

and the bearing case

4

c

form a positioning part for positioning the process cartridge

3

in the apparatus main body

1

.

On the other hand, when the toner supply container

50

is inserted into the backmost part, the supporting pin

67

b

protruding from the back side plate

1

d

is inserted in the recessed part

51

a

provided on the back side of the frame

51

, whereby a standard position of the toner supply container

50

is determined. A supporting pin

67

c

also provided in the back side plate

1

d

is inserted in the recessed part

51

b

provided on the back side of the frame

51

, which acts as a detent to fix the position of the frame

51

of the toner supply container

50

. In addition, the driving couplings (recesses)

60

a

and

60

b

and the driving couplings (protrusions)

61

a

and

61

b

are coupled simultaneously, thereby enabling the rotational driving of the screw

58

and the agitating shaft

56

.

In addition, a supporting pin

67

d is provided on a front side plate

1

c

of the apparatus main body

1

. A position of the toner supply container

50

on the front side is determined by the engagement of the supporting pin

67

d

and a recessed part

68

a

provided in a holder

68

attached to the toner supply container

50

. That is, a positioning part for positioning the toner supply container

50

in the apparatus main body

1

is formed by the supporting pins

67

b

,

67

c

and

67

d

and the recessed parts

51

a

,

51

b

and

68

a

. A driving force is transferred by the driving couplings (recesses)

60

a

and

60

b

and the driving couplings (protrusions)

61

a

and

61

b.

(Description of a State in Which a Developer is Consumed)

Situations in which toner in the toner containing portion

52

is consumed will now be described with reference to

FIGS. 10

to

12

.

FIG. 10

illustrates a -state in which a toner containing portion

52

is sufficiently filled with toner,

FIG. 11

illustrates a state in which the toner in the toner containing portion

52

decreases and

FIG. 12

illustrates a state in which the toner in the toner containing portion

52

is running out.

As described above, the agitating plate

57

or the first feeding member is formed symmetrically around the receiving port

55

a

and generates a feeding force in an arc part on the bottom surface of the toner supply container

50

, whereby toner in the toner containing portion

52

is fed in the direction of the receiving port (outlet of the containing chamber)

55

a

from the both sides of the toner containing portion

52

. Then, when the toner containing portion

52

is sufficiently filled with toner T as shown in

FIG. 10

, in the position of the receiving port

55

a

, the toner T moves to the upper part where the feeding force is weak and circulates in the directions indicated by the arrows in FIG.

10

.

On the other hand, the toner T existing in the receiving port

55

a

falls into the toner feeding portion

54

by free fall and is fed in the direction of the outlet (outlet of the containing chamber)

53

a

by the screw

58

or the second feeding member. Then, the toner T in the toner containing portion

52

is gradually discharged from the outlet

53

a

and consumed as shown in FIG.

11

. At this point, the toner T is collected in the receiving port

55

a

while circulating as shown in FIG.

11

. The part surrounding the receiving port

55

a

is filled with the toner T even while the toner T is being consumed. Thus, the amount of the toner T existing in the toner feeding portion

54

is the same as that existing there in the state in which the toner containing portion

52

is sufficiently filled with the toner T. In other words, since a toner feeding amount for one revolution of the first feeding member

57

is larger than a toner feeding amount for one revolution of the second feeding member

58

, toner always exists in the receiving port

55

a.

Finally, the toner T in the toner containing portion

52

is almost completely consumed. However, since the toner T in the toner containing portion

52

always continues to fill the part around the receiving port

55

a

, the amount of toner in the toner feeding portion

54

is constant from the initial period of using the toner supply container

50

to the time when the toner is almost completely consumed in the end. In this way, the amount of the toner T falling into the toner feeding portion

54

is always maintained constant. Thus, it becomes possible to manage the feeding amount of toner by managing the number of revolutions of the screw

58

or the second feeding member and, whereby it eventually becomes possible to always stabilize the amount of toner discharged from the outlet

53

a.

As described above, stabilization of the amount of toner discharged from the outlet

53

a

of the toner supply container

50

can be attained by maintaining constant the toner amount in the toner feeding portion

54

fed by the screw

58

or the second feeding means by the receiving port

55

a

and the agitating plate

57

or the first feeding means.

In addition, the screw

58

for supplying toner to the developing device

15

is provided in the toner supply container

50

. Thus, it is sufficient to dispose a sealing member for preventing leakage of the toner only between the outlet

53

a

of the toner supply container

50

and the supply port

25

of the developing device

15

, and parts to be sealed can be restrained to the minimum required.

(Other Embodiments)

In the above-mentioned embodiment, the partition plate

55

is described as being formed of a sheet member of resin. However, a material of the partition plate

55

may be any material such as metal, paper and wood as long as it partitions the toner containing portion

52

and the toner feeding portion

54

. In addition, the partition plate

55

may be integrally formed with the frame

51

.

In addition, in the above-mentioned embodiment, the agitating plate

57

or the first feeding member is described as being formed of a flexible sheet member that obtains a feeding force by being twisted. However, a material of the agitating plate

57

may be any material as long as it feeds the toner in the toner containing portion

52

in the direction of the receiving port

55

a

. For example, the feeding member

69

having a spiral rib shape (a so-called screw) as shown in

FIG. 13

, a coil or the like may be used. Moreover, the receiving port

55

a

is disposed substantially in the center of the toner containing portion

52

. However, this disposition is for the purpose of reducing costs by shortening the screw

58

or the second feeding means, and the receiving port

55

a

may be disposed in the end part on the front side as shown in FIG.

13

.

Further, the developer supply container in accordance with the present invention is not limited to the two-component development method, and can supply a developer in a process cartridge or a developing cartridge using a mono-component development method. In addition, powder to be contained in the developer supply container is not limited to toner, and a mixture of toner and a magnetic carrier, or a so-called two-component developer may be contained.

As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.

Number	Name	Date	Kind
5206692	Ishida et al.	Apr 1993	A
5655195	Ichikawa et al.	Aug 1997	A
6137978	Tsuchiya et al.	Oct 2000	A
6229976	Kimura	May 2001	B1
6324370	Isobe et al.	Nov 2001	B1

Developer supply container and image forming apparatus capable of mounting the container thereon

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (1)

US Referenced Citations (5)