Process cartridge and electrophotographic image forming system

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a process cartridge detachably mountable to an electrophotographic image forming apparatus and an electrophotographic image forming system, and particularly to a process cartridge detachably mountable to at least two kinds of electrophotographic image forming apparatuses differing in function from each other, and an electrophotographic image forming system using the process cartridge.

The electrophotographic image forming apparatus is an apparatus for forming an image on a recording medium by the use of the electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copier, an electrophotographic printer (such as a laser beam printer or an LED printer), a facsimile apparatus and a word processor.

Also, the process cartridge refers to charging means, developing means or cleaning means and an electrophotographic photosensitive drum integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus, or at least one of charging means, developing means and cleaning means and an electrophotographic photosensitive drum integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus, or at least developing means and an electrophotographic photosensitive drum integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus.

2. Description of the Related Art

In the electrophotographic image forming apparatus using the electrophotographic image forming process, there is adopted a process-cartridge system in which an electrophotographic photosensitive member and process means for acting on the electrophotographic photosensitive member are integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus. According to this process cartridge system, the maintenance of the apparatus can be done by a user himself without resorting to a serviceman and therefore, the operability of the apparatus can be markedly improved. Therefore, this process cartridge system is widely used in the electrophotographic image forming apparatuses.

Also, in the electrophotographic image forming apparatus of the process cartridge type, as described above, the user himself interchanges the process cartridge and therefore, electrophotographic image forming apparatuses are provided with developer amount detecting means for informing the user when a developer (e.g. a toner) has been consumed. As this developer amount detecting means, there is a system for detecting any change in the capacitance among a plurality of electrodes disposed in the process cartridge to thereby detect the amount of developer.

As the constructions of these electrodes, there are an electrode-rod-detection type (a developer-remaining-amount-presence-or-absence detecting type) in which an electrode rod is disposed at a predetermined interval from a developer bearing member and the capacitance between it and the developer bearing member is detected, and an electrode-plate-detection type (a developer-remaining-amount-successively-detecting type) in which a plurality of electrode plates opposed to one another are disposed at locations into which a developer can go, and the capacitance between the electrode plates is detected.

Generally, developer amount detecting means of the above-described electrode-rod-detection type or the electrode-plate-detection type is alternatively provided in the process cartridge in accordance with the function of the main body of the image forming apparatus. Therefore, a process cartridge provided with the developer amount detecting means of the electrode-rod-detection type could be mounted only to an image forming apparatus for the electrode-rod-detection type, and a process cartridge provided with the developer amount detecting means of the electrode-plate-detection type could be mounted only to an image forming apparatus for the electrode-plate-detection type.

The present invention is a further development of the above-described related art.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a process cartridge detachably mountable to the main bodies of electrophotographic image forming apparatuses differing in function from each other, and an electrophotographic image forming system using the process cartridge.

It is another object of the present invention to provide a process cartridge capable of being mounted to the main body of an electrophotographic image forming apparatus having a function for successively detecting a remaining amount of developer (a developer-remaining-amount-successively-detecting function) and the main body of an electrophotographic image forming apparatus having a function for detecting that developer is consumed to a predetermined remaining amount (a developer-remaining-amount-presence-or-absence-detecting function), and an electrophotographic image forming system using the process cartridge.

It is another object of the present invention to provide a process cartridge detachably mountable to the main body of a first electrophotographic image forming apparatus and the main body of a second electrophotographic image forming apparatus differing in function from the first electrophotographic image forming apparatus and to provide an image forming system using the process cartridge, the process cartridge having (a) an electrophotographic photosensitive member, (b) a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive member, (c) a developer containing portion for containing therein a developer to be used to develop the electrostatic latent image by the developing roller, (d) a first electrically conductive member disposed along the lengthwise direction of the developing roller and having one end thereof exposed from a cartridge frame, the one end being electrically connected to a first main body contact provided in the main body of the first electrophotographic image forming apparatus when the process cartridge has been mounted to the main body of the first electrophotographic image forming apparatus, and producing an electrical signal for indicating that the process cartridge has been mounted to the main body of the first electrophotographic image forming apparatus, the one end being not electrically connected to the interior of the main body of the second electrophotographic image forming apparatus when the process cartridge has been mounted to the main body of the second electrophotographic image forming apparatus, and (e) a second electrically conductive member disposed along the lengthwise direction of the developing roller and electrically connected to a cartridge electrical contact exposed from the cartridge frame, the cartridge electrical contact being electrically connected to a second main body contact provided in the main body of the second electrophotographic image forming apparatus when the process cartridge has been mounted to the main body of the second electrophotographic image forming apparatus, and producing an electrical signal for the main body of the second electrophotographic image forming apparatus to successively detect the remaining amount of the developer, the cartridge electrical contact being not electrically connected to the interior of the main body of the first electrophotographic image forming apparatus when the process cartridge is mounted to the main body of the first electrophotographic image forming apparatus.

These and other objects, features and advantages of the present invention will become more fully apparent upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a schematic view showing in longitudinal cross-section a state in which a process cartridge is being mounted to an image forming apparatus provided with a successive toner-remaining-amount detecting circuit.

FIG. 2

is a longitudinal cross-sectional view of the process cartridge of the present invention.

FIG. 3

is a circuit diagram showing an example of a developer-amount detecting circuit for detecting the capacitance with which developer amount detecting means has been charged.

FIG. 4

is an exploded perspective view showing the manner in which a first electrode and a third electrode are attached to a developing frame.

FIG. 5

is an exploded perspective view showing the manner in which a second electrode is attached to the developing frame.

FIG. 6

is a right side view of the process cartridge showing the disposition of an external contact provided on a side of the process cartridge.

FIG. 7

is a perspective view showing a state in which the opening-closing member of the image forming apparatus having the successive toner-remaining-amount detecting circuit is opened.

FIG. 8

is an exploded perspective view for showing the manner in which an antenna rod, which is second detecting means, and a developing blade, are mounted.

FIG. 9

is an exploded perspective view for showing the manner in which the developing frame and a toner container are coupled together after the first to third electrodes have been attached to the developing frame.

FIG. 10

is a plan view showing the connected portions of the first electrode and the third electrode.

FIG. 11

is a perspective view showing a state in which the opening-closing member of an image forming apparatus provided with a toner-presence-or-absence detecting circuit (mechanism) is opened.

FIG. 12A

is a schematic cross-sectional view showing the manner in which the process cartridge is mounted to the image forming apparatus provided with the toner-presence-or-absence detecting circuit (mechanism).

FIG. 12B

is an enlarged view of an encircled portion XIIB in FIG.

12

A.

FIG. 13

is a schematic view showing in longitudinal cross-section a state in which the process cartridge is being mounted to the image forming apparatus provided with the toner presence or absence detecting circuit (mechanism).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will hereinafter be provided of a process cartridge according to an embodiment of the present invention and an electrophotographic image forming apparatus using the same. Herein, an image forming apparatus A refers to an electrophotographic image forming apparatus for the electrode-rod-detection type, and an image forming apparatus A′ refers to an electrophotographic image forming apparatus for the electrode-plate-detection type.

(Description of the Image Forming Apparatus and the Process Cartridge)

An example of the general construction of the electrophotographic image forming apparatus (hereinafter referred to as the image forming apparatus) will first be described with reference to FIG.

1

.

FIG. 1

is a schematic view showing the longitudinal cross-section of the image forming apparatus A′ as it has the process cartridge B of the present invention mounted thereto.

A drum-shaped electrophotographic photosensitive member (hereinafter referred to as the photosensitive drum

7

), which is a form of an image bearing member, is provided in the process cartridge B in the image forming apparatus A′ . The photosensitive drum

7

is rotated in the direction indicated by the arrow in FIG.

1

and is charged by a charging roller

8

which is charging means. A laser beam conforming to image information is then applied from optical means 1 having a laser diode, a polygon mirror, a lens and a reflecting mirror to the photosensitive drum

7

, whereby a latent image conforming to the image information is formed on the photosensitive drum

7

. The latent image is developed by developing means 10 and is made into a toner image which is a visible image.

The developing means 10 comprises a developing roller

12

, which is a developer bearing member, for feeding a developer (toner) to the photosensitive drum

7

, and a developing blade

18

, which is a regulating member for regulating the amount of the developer adhering to the surface of the developing roller

12

. Also, the developing roller

12

, the developing blade

18

, a developing frame

13

holding them, and a toner container

11

(referred to also as a developer frame) containing the developer therein are coupled together to thereby constitute a developing unit

20

, which is a developing device.

The developing roller

12

has its outer surface formed into a substantially cylindrical shape, is rotatably supported by a developing frame

13

, and contains a stationary magnet

17

therein. The developing blade

18

is disposed at a suitable interval from and substantially in parallel to the developing roller

12

. The toner container

11

forms a toner containing portion

14

containing therein a toner, which is the developer, and is provided with a toner feeding member

15

for feeding the toner in the toner containing portion

14

. The toner feeding member

15

has a plastic sheet having flexibility and elasticity. The toner container

11

constitutes the toner containing portion

14

, is secured to the developing frame

13

, and supplies the toner in the toner containing portion

14

to the developing frame

13

.

The developing frame

13

has a developing chamber

13

a

, and the toner in the toner containing portion

14

adjacent to the developing chamber

13

a

is fed to the developing chamber

13

a

by the rotation of a toner feeding member

15

. The developing frame

13

is provided with a rotatable toner agitating member

16

near the developing roller

12

, and causes the toner in the developing chamber

13

a

fed from the toner containing portion

14

to be circulated by the rotation of the toner agitating member

16

. Also, the toner has magnetism and the developing roller

12

contains the stationary magnet

17

therein and therefore, the toner adheres onto the developing roller

12

.

By the developing roller

12

being rotated, the toner is carried, and triboelectrification charges are induced by the blade

18

and also a toner layer of a predetermined thickness is formed on the developing roller

12

, and the toner is carried to the developing area of the photosensitive drum

7

. The toner supplied to the developing area is shifted to the latent image on the photosensitive drum

7

to thereby form a toner image on the photosensitive drum

7

. The developing roller

12

is connected to a developing bias circuit provided in the main body of the image forming apparatus, and a developing bias voltage comprising a DC voltage superimposed on an AC voltage is usually applied thereto.

On the other hand, in synchronism with the formation of the toner image, a recording medium

2

, such as paper set in a feed cassette

3

a

, is transported to a transfer position by a pickup roller

3

b

, a pair of transporting rollers

3

c

and

3

d

, and a pair of registration rollers

3

e

. A transfer roller

4

as transferring means is disposed at the transfer position, and a voltage is applied to the transfer roller

4

, whereby the toner image on the photosensitive drum

7

is transferred to the recording medium

2

.

The recording medium

2

having received the transfer of the toner image is transported to fixing means

5

by a transport guide

3

f

. The fixing means

5

is provided with a driving roller

5

c

and a fixing rotary member

5

b

comprising a cylindrical sheet containing a heater

5

a

therein and supported by a support member

5

d

, and applies heat and pressure to the recording medium

2

passing therethrough to thereby fix the transferred toner image on the recording medium

2

.

The recording medium

2

on which the toner image has been fixed is transported by a pair of delivery rollers

3

g

, and is delivered to a delivery tray

6

by a pair of delivery rollers

3

h

via a surface reverse path

3

j

. The delivery tray

6

is provided on the upper surface of the image forming apparatus A′ . It is also possible to operate a rockable flapper

3

k

to thereby deliver the recording medium

2

without the intermediary of the surface reverse path

3

j

. In the present embodiment, the pickup roller

3

b

, the pairs of transporting rollers

3

c

and

3

d

, the pair of registration rollers

3

e

, the transport guide

3

f

, and the pairs of delivery rollers

3

g

and

3

h

together constitute transporting means.

Also, the photosensitive drum

7

from which the toner image has been transferred to the recording medium

2

by the transfer roller

4

has any toner residual thereon removed by cleaning means

9

, whereafter it is used for the next image forming process. The cleaning means

9

comprises an elastic cleaning blade

9

a

provided in abutting relationship with the photosensitive drum

7

, and a removed toner reservoir

9

b

for containing the residual toner therein. The removed toner reservoir

9

b

is formed by a cleaning fame

9

c

, which in turn supports the cleaning blade

9

a

. The cleaning means

9

scrapes off the residual toner on the photosensitive drum

7

by the cleaning blade

9

a

, and collects it into the removed toner reservoir

9

b

.

On the other hand, as shown in

FIG. 2

, in the present embodiment, the process cartridge B forms the developing unit

20

(developing device) by the toner container

11

being welded to the developing frame

13

provided with the developing means

10

. The toner container

11

forms the toner containing portion

14

containing the toner therein, and the toner feeding member

15

is pivotally supported in the toner containing portion

14

. The developing frame

13

holds the developing roller

12

and the developing blade

18

, which are the developing means

10

.

Also, the cleaning means

9

such as the cleaning blade

9

a

, the photosensitive drum

7

and the charging roller

8

are supported by the cleaning frame

9

c

to thereby form a cleaning unit

19

.

The process cartridge B is provided by the developing unit

20

and the cleaning unit

19

being rotatably coupled together into a unit and thereby made into a cartridge.

In the present embodiment, the process cartridge B is provided with first developer amount detecting means (hereinafter referred to as the first detecting means) for detecting the absence of the toner in the developing chamber

13

a

, and second developer amount detecting means (hereinafter referred to as the second detecting means) for successively detecting the remaining amount of the toner in accordance with the consumption of the toner in the developing chamber

13

a

.

(Description of the First Detecting Means (toner-remaining-amount-presence-or-absence detection))

The first detecting means will be described here. The first detecting means is detecting means of the electrode-rod-detection type, and as shown in

FIG. 2

, is comprised of a portion of an antenna rod

89

, which is a metal wire formed of an electrically conductive material such as a non-magnetic stainless steel material or an aluminum material, provided along the lengthwise direction of the developing roller

12

and substantially in parallel to the developing roller

12

. The antenna rod

89

, if formed of one of electrically conductive materials, will act in the same way, but in the present embodiment, it uses a non-magnetic stainless steel material (SUS material) so as not to affect the circulation of the magnetic toner.

The antenna rod

89

is provided in the developing frame

13

, and more particularly, is provided over the full length of the developing roller

12

and at a predetermined distance from the developing roller

12

. The capacitance between the antenna rod

89

and the developing roller

12

is varied by the amount of toner present between the two. So, this variation in the capacitance is detected as a potential difference variation by a toner amount detecting contact in the main body of the image forming apparatus A for the electrode rod detection type to thereby detect the presence or absence of the remaining amount of toner.

Also, the capacitance between the antenna rod

89

and the developing roller

12

is detected to thereby judge whether the process cartridge B has been mounted to the main body of the image forming apparatus A. That is, when the process cartridge B has been mounted to the main body of the image forming apparatus A, the main body of the image forming apparatus A receives the capacitance between the antenna rod

89

and the developing roller

12

as an electrical signal, and detects that the process cartridge B has been mounted.

The antenna rod

89

forming the first detecting means does not successively detect the amount of toner, but effects the detection of the absence of the toner near the developing roller

12

.

(Description of the Second Detecting Means (toner-remaining-amount successive detection))

The second detecting means will now be described. The second detecting means is detecting means of the electrode-plate-detection type, and in the present embodiment, as shown in

FIG. 2

, as measuring electrode members constituting the second detecting means, a first electrode

81

, a second electrode

82

, and a third electrode

83

are provided in the developing frame

13

and are disposed along and in parallel to the developing roller

12

. The first to third electrodes

81

,

82

, and

83

are formed of a non-magnetic stainless steel material, an aluminum material, or electrically conductive resin, or the like. While in the present embodiment, the first to third electrodes

81

,

82

and

83

comprising three electrode plates are provided as the measuring electrode members constituting the second detecting means, this is not restrictive, but the number of the electrodes may be one, two or four or more.

The first electrode

81

is provided near and along the developing roller

12

, the third electrode

83

is provided at the bottom of the developing frame

13

, and the first electrode

81

and the third electrode

83

are electrically connected together in the developing frame

13

and assume the same potential.

Also, the second electrode

82

is provided more toward the toner container

11

than the first electrode

81

, and is disposed in the upper portion of the developing frame

13

so as to be opposed to the first electrode

81

and the third electrode

83

. The second detecting means induces capacitance between the electrodes by a voltage being applied to one of the first electrode

81

and the second electrode

82

, and is designed to measure the capacitance by a detecting circuit provided in the image forming apparatus A′ (which will be described later) to thereby detect the amount of toner.

That is, the toner goes into between the electrodes, whereby the capacitance between the electrodes is varied and therefore, by detecting the variation, the amount of toner can be detected. In the present embodiment, a voltage is applied to the second electrode

82

to thereby make the second electrode

82

into an input side, and make the first electrode

81

and the third electrode

83

into an output side.

The first, second, and third electrodes

81

,

82

, and

83

are disposed at locations into which the toner carried from the toner container

11

by the toner feeding member

15

can go, and when the amount of toner in the process cartridge B is great, the toner is forced into the space surrounded by the electrodes by the toner feeding member

15

and therefore, the capacitance between the electrodes continues to exhibit a high value. However, as the process cartridge is used, the toner is consumed and the height of the toner between the second electrode

82

and the first electrode

81

and between the second electrode

82

and the third electrode

83

decreases, and the capacitance between the electrodes also decreases. From the decrease in the capacitance, the remaining amount of toner is successively detected.

Finally, the toner near the fore end of the developing blade

18

, which scrapes off the toner on the surface of the developing roller

12

, is consumed, whereby a blank area on an image is created to thereby bring about a toner-absent state. In the present embodiment, the developing bias voltage applied to the developing roller

12

is used as an input voltage and the capacitance between the developing roller

12

and the first electrode

81

(and the third electrode

83

) is also detected to thereby detect the toner-absent state. That is, the second detecting means can detect any variation in the capacitance among a plurality of electrodes to thereby successively detect the amount of toner.

The process cartridge of the present embodiment is provided with two developer amount detecting means as described above, whereby it is adapted to be capable of coping with any one of the main body of an image forming apparatus of a type having a mechanism for successively detecting the amount of toner and the main body of an image forming apparatus of a type having no successively detecting mechanism and effecting only the detection of the absence of the toner.

(Description of the Detecting Circuit)

FIG. 3

is a circuit diagram showing an example of the developer amount detecting circuit for detecting the amount of developer in the image forming apparatus A′ and the process cartridge B.

The developer amount detecting circuit

200

comprises a detecting portion

80

, a developing bias circuit

201

, a controlling circuit

202

, and an amplifying circuit

204

. The detecting portion

80

comprises the first, second, and third electrodes

81

,

82

and

83

, which are the first detecting means, and the developing roller

12

, and induces a capacitance to detect the amount of toner. This detecting portion

80

is provided in the process cartridge B.

On the other hand, the developing bias circuit

201

, the controlling circuit

202

and the amplifying circuit

204

are provided in the main body of the image forming apparatus A′.

External contacts

22

a

and

23

a

, which are electrical contacts with the image forming apparatus A′, are provided on a side of the frame of the process cartridge B, and when the process cartridge B is mounted to the main body of the image forming apparatus A′, the external contacts

22

a

and

23

a

contact electrical contacts

30

and

31

, respectively, provided on the image forming apparatus A′ side.

The capacitance Ca of the detecting portion

80

is the capacitance between the second electrode

82

and the first electrode

81

and between the second electrode

82

and the third electrode

83

, and the magnitude thereof fluctuates in conformity with the amount of toner.

The detecting portion

80

has one input side electrode thereof as an impedance element connected to the developing bias circuit

201

, which is developing bias applying means, and the controlling circuit

202

. In the present embodiment, the second electrode

82

is an input side electrode, and the second electrode

82

is connected to the developing bias circuit

201

through the external contact

22

a

and the electrical contact

30

of the main body of the image forming apparatus A′, and is connected to the controlling circuit

202

via a wire laying portion

36

for electrical wires in the main body of the image forming apparatus A′.

The detecting portion

80

has its other output side electrode connected to the controlling circuit

202

. In the present embodiment, the first and third electrodes

81

and

83

are connected to the controlling circuit

202

through the external contact

23

a

and the electrical contact

31

of the main body of the apparatus and via a wire laying portion

37

for the wires in the main body of the image forming apparatus A′.

The process cartridge B is provided with a developing bias contact

12

a

, which conducts with the developing roller

12

, and the image forming apparatus A′ is provided with a developing contact member

103

which conducts with the developing bias circuit

201

. When the process cartridge B is mounted to the image forming apparatus A′, the developing bias contact

12

a

and the developing contact member

103

provided in the image forming apparatus A′ are electrically connected together, and a developing bias voltage is applied from the developing bias circuit

201

of the image forming apparatus A′ to the developing roller

12

via the developing contact member

103

and the developing bias contact

12

a

.

A reference capacitance element Cb is provided in the controlling circuit

202

and is connected to the developing bias circuit

201

in the image forming apparatus A′. The reference capacitance element Cb sets a reference voltage V

1

, which becomes the reference in detecting the amount of toner, by the use of an AC (alternating current) I

1

applied from the developing bias circuit

201

. The controlling circuit

202

divides the AC I

1

applied to the reference capacitance element Cb by a volume VR

1

, and adds a voltage drop V

2

occurring in a resistor R

2

by the divided AC I

1

′ to a set voltage V

3

set by a resistor R

3

and a resistor R

4

to thereby determine a reference voltage V

1

.

The amplifying circuit

204

is provided with a comparator for calculating the difference between voltages, and an AC I

2

applied to the detecting portion

80

is inputted to the amplifying circuit

204

and is outputted as the detected value V

4

(=V

1

−I

2

×R

5

) of the amount of toner. The remaining amount of toner is detected on the basis of this detected value V

4

which is the difference from the reference voltage V

1

. The information of the thus detected remaining amount of toner is reported to an operator (user) as by an indicating portion (not shown) provided in the main body of the image forming apparatus A′.

According to the image forming apparatus A′ of the present invention, the remaining amount of toner in the process cartridge B is successively detected by the second detecting means and on the basis of the information thereof, the consumed amount of toner is indicated, whereby the user can be pressed for the preparation of a fresh process cartridge or a supply cartridge. Further, the user can be pressed for the interchange of the process cartridge or the supply of the toner by the detection information of the absence of the toner.

(Description of the Attachment of the Electrodes and the Antenna Rod)

A description will now be made of the structure for attaching the antenna rod

89

, which is the first detecting means, and the first electrode

81

, the second electrode

82

, and the third electrode

83

, which are the second detecting means, to a portion constituting the developing device.

The second detecting means comprising the first electrode

81

, the second electrode

82

, and the third electrode

83

, is realized by detecting the capacitance of the space surrounded by the second electrode

82

and the first and third electrodes

81

and

83

and therefore, the positional accuracy of each electrode is very important. Also, the first detecting means is realized by detecting the capacitance between the antenna rod

89

and the developing roller

12

and therefore, the positional accuracy of the antenna rod

89

is also very important. Particularly the intervals among the respective electrodes

81

,

82

, and

83

and the positions of the respective electrodes relative to the developing roller

12

and the developing blade

18

need be accurately determined in order to detect the amount of toner accurately. Also, in the present invention, it is necessary to dispose each electrode nearer to the developing roller

12

on which the toner remains to the last in order to accurately detect the time when the toner is exhausted and a blank area on an image is created.

So, in the present embodiment, as shown in

FIGS. 4 and 5

, the electrodes

81

,

82

,

83

and the antenna rod

89

are attached to the developing frame

13

.

FIG. 4

is an exploded perspective view showing the manner in which the first electrode

81

and the third electrode

83

are attached to the developing frame

13

. As shown in

FIG. 4

, the first electrode

81

forms a thin plate-like shape and is of a shape in which a side (lower side) thereof is bent substantially at a right angle with some width given thereto. Positioning apertures

81

d

for positioning bosses

13

c

to fit thereto are formed in the opposite ends of the first electrode

81

. One end portion (the end portion on this side as viewed in

FIG. 4

) of the first electrode

81

is provided with an arm portion

81

a

narrower in width than the first electrode

81

and bent into a crank-like shape toward the developing frame

13

on the lengthwise extension of the first electrode. Further, the end portion of the arm portion

81

a

is formed with an incised clinch

81

b

, which is an electrical connecting portion having its plate surface bent at

90

° with respect to the plate surface of the first electrode

81

, and the incised clinch

81

b

is formed with an aperture

81

c

. The plate surface of the end portion of the arm portion

81

a

is also orthogonal to an attachment surface

13

b

to which the first electrode

81

is attached, and has a vertical plate surface.

The first electrode

81

is made parallel to the lengthwise direction of the developing frame

13

and is moved in the widthwise direction of the developing frame

13

, and the positioning bosses

13

c

provided on the opposite end portions of the attachment surface

13

b

formed on the developing frame

13

are fitted to the positioning apertures

81

d

formed in the first electrode

81

to thereby position the first electrode, which is then stuck on the attachment surface

13

b

by an adhesive double coated tape. The electrode attaching method is not restricted to the adhesive double coated tape, but yet it is difficult in some cases to secure a space for screwing in the developing frame

13

because in order to reliably detect a blank area on an image, the first electrode

81

is provided near the developing roller

12

and the developing blade

18

on which the toner is lastly consumed. Therefore, in the present embodiment, use is made of the fixing by the adhesive double coated tape, which does not require such a space.

Also, the developing frame

13

is formed with a groove

13

d

long in a direction substantially orthogonal to the attachment surface

13

b

(see FIG.

10

). When the first electrode

81

is stuck on the attachment surface

13

b

and is attached to the developing frame

13

, the end portion of the arm portion

81

a

having the incised clinch

81

b

is adapted to go into the groove

13

d

of the developing frame

13

. Laterally of the groove

13

d

of the developing frame

13

, there is formed a tunnel

13

e

extending from the interior of the developing frame

13

toward the exterior of the developing frame

13

, and the location of the tunnel

13

e

is determined so as to align with the aperture

81

c

in the incised clinch

81

b

when the first electrode

81

is attached to the developing frame

13

.

The third electrode

83

forms a thin plate-like shape, and the opposite end portions thereof are formed with arm portions

83

a

and

83

b

. The arm portions

83

a

and

83

b

are bent in a direction substantially orthogonal to the plate surface of the third electrode

83

, and the arm portions

83

a

and

83

b

are formed with positioning apertures

83

e

for positioning bosses

13

k

to fit thereto and screw apertures

83

f

. Also, the end portion of the arm portion

83

a

is formed with an incised clinch

83

c

(electrical connecting portion) similar in shape to the incised clinch

81

b

of the first electrode

81

, perpendicularly to the plate surface of the arm portion

83

a

and the plate surface of the third electrode

83

.

To attach the third electrode

83

to the developing frame

13

, the third electrode

83

is moved in the widthwise direction of the developing frame

13

, the positioning apertures

83

e

of the arm portions

83

a

and

83

b

are fitted on the positioning bosses

13

k

, and are brought into abutting relationship with the attachment portions

13

i

and

13

j

of the developing frame

13

, and small screws

41

are screwed into the screw apertures

83

f

and internally threaded holes

13

p

to thereby fix the third electrode. At this time, the end portion of the arm portion

83

a

having the incised clinch

83

c

fits into the groove

13

d

of the developing frame

13

. The incised clinch

83

c

is formed with an aperture

83

d

so that the incised clinch

83

c

and the incised clinch

81

b

may form a line when the third electrode

83

is attached to the developing frame

13

.

As shown in

FIG. 10

, after the attachment of the first electrode

81

, the third electrode

83

is attached to the developing frame

13

and is assembled, whereupon the incised clinch

83

c

thereof comes into contact with the arm portion

81

a

of the first electrode

81

and the arm portion

81

a

is flexed, and in this state, the aperture

83

d

and the aperture

81

c

are adapted to overlap each other. That is, the incised clinch

83

c

of the third electrode

83

corrects the position of the incised clinch

81

b

of the first electrode

81

to thereby improve the assembling property for the pressfit of the electrode rod

25

thereafter.

Also, the tunnel

13

e

of the developing frame

13

is of a shape in which an elastic seal member

24

is fitted therein, and the elastic seal member

24

is forced thereinto from the outside of the developing frame

13

. One end of a columnar electrode rod

25

formed into a U-shape is inserted into the tunnel

13

e

of the developing frame

13

through the elastic seal member

24

, and is forced into the aperture

81

c

and the aperture

83

d

in the developing frame

13

, whereby the first electrode

81

and the third electrode

83

are electrically connected together.

A holder

90

for rotatably supporting the developing roller

12

by a bearing portion is mounted on a side of the developing frame

13

. A portion of an electrode plate

23

is fitted to a square window portion

90

a

provided in the holder

90

to thereby constitute an external contact

23

a

for electrically connecting the image forming apparatus and the process cartridge B together. The electrode plate

23

is provided with a contact portion

23

b

, and when the holder

90

is mounted on the developing frame

13

, the contact portion

23

b

contacts with the electrode rod

25

, whereby the external contact

23

a

, the first electrode

81

and the third electrode

83

are electrically connected together.

FIG. 5

is an exploded perspective view showing the manner in which the second electrode

82

is attached to the developing frame

13

. As shown in

FIG. 5

, the second electrode

82

forms a shape in which a thin plate is bent substantially at a right angle, and arm portions

82

a

are formed on the opposite ends thereof. The arm portion

82

a

of the second electrode

82

are formed with positioning apertures

82

b

for positioning bosses

13

h

provided on the developing frame

13

to fit thereinto and screw holes

82

c

.

When the second electrode

82

is to be attached to the developing frame

13

, the positioning bosses

13

h

of the developing frame

13

are fitted into the positioning apertures

82

b

of the second electrode

82

to thereby position the second electrode, and small screws

42

are screwed into the screw holes

82

c

and into the internally threaded holes

13

q

of the developing frame

13

to thereby fix the second electrode. At this time, one small screw

42

(this side as viewed in

FIG. 5

) is inserted into the screw hole

26

c

of an electrode plate

26

to thereby fasten the electrode plate

26

with the second electrode

82

, and the wiring to the outside of the developing frame

13

is effected by the electrode plate

26

. The second electrode

82

should desirably be assembled after the attachment of the first electrode

81

so as not to spoil the assembling property of the first electrode

81

.

As previously described, the second electrode

82

differs in potential from the first and third electrodes

81

and

83

and therefore, if in case of the wiring to each electrode, the electrode plates for wiring are disposed in opposed relationship with each other, a capacitance will be induced between the electrode plates for wiring and this will cause a lowering of the accuracy of toner-remaining-amount detection. The electrode plate

26

is an electrode plate for the wiring to the second electrode

82

and therefore, the wiring from the developing frame

13

to the toner container

11

is effected by the electrode plate

26

so that the electrode plate

23

for the wiring to the first and third electrodes

81

and

83

may not be disposed at a location opposed to the electrode plate

26

. Herein, the electrode plate for wiring refers to an electrode plate used as wiring for transmitting electricity.

The coupling construction for the developing frame

13

and the toner container

11

forming the toner containing portion

14

will now be described with reference to FIG.

9

.

FIG. 9

is a perspective view showing the manner in which the developing frame

13

and the toner container

11

are coupled together after the first to third electrodes

81

,

82

and

83

have been attached to the developing frame

13

.

As shown in

FIG. 9

, convex portions

13

f

and

13

g

for fitting into concave grooves for coupling (not shown) formed in the toner container

11

are provided on the joined surface of the developing frame

13

with the toner container

11

. The convex portions

13

f

and

13

g

are long in the lengthwise direction of the developing frame

13

in the upper and lower portions thereof, and are parallel to each other. Triangular ribs used for ultrasonic welding are provided on the top surfaces of these convex portions

13

f

and

13

g

.

Also, seal members

27

and

28

are stuck on the opposite end portions of the developing frame

13

so as to prevent the leakage of the toner from between the developing frame

13

and the toner container

11

. Also, a seal member

29

is stuck so as to surround the contact portion

26

a

of the electrode plate

26

so that the toner may not leak from around the electrode plate

26

for the wiring to the toner container

11

. These seal members

27

,

28

and

29

use a sponge-like material having elasticity.

The developing frame

13

into which each part has been incorporated and the toner container

11

are pressed with the concave grooves of the toner container

11

and the convex portions

13

f

and

13

g

of the developing frame

13

fitted together, and further, ultrasonic vibration is applied between the concave grooves and the convex portions. Thereupon, the triangular ribs provided on the convex portions

13

f

and

13

g

are melted by the ultrasonic vibration and are welded to the bottoms of the concave grooves, whereby the developing frame

13

and the toner container

11

are integrally coupled together.

In the present construction, an electrode plate

22

for wiring is attached to the toner container

11

. The electrode plate

22

is provided with an external contact

22

a

for connection to the main body of the image forming apparatus, and a contact portion

22

b

for connection to the electrode plate

26

. The electrode plate

22

is attached to the outer side of the toner container

11

. The contact portion

22

b

of the electrode plate

22

is provided on the end of a portion nipping the upper edge of the flange

11

a

of the toner container

11

, and is disposed at a location opposed to the contact portion

26

a

. The electrode plate

22

is disposed along the outer side of the flange

11

a

of the toner container

11

, and is fitted into and fixed to a dowel

11

b

protruding from the toner container

11

outwardly in the lengthwise direction thereof. The external contact

22

a

is disposed along the contact seat

11

c

of the toner container

11

, and that surface of the external contact

22

a

which provides a contact, like the external contact

23

a

, faces outwardly in the lengthwise direction thereof.

The electrical connection between the electrode plate

22

and the electrode plate

26

is made by the contact between the contact portion

22

b

and the contact portion

26

a

, and they contact with each other and are electrically connected together when the developing frame

13

and the toner container

11

are coupled together.

The electrode plate

22

has its plate surface disposed so as to be substantially orthogonal to the plate surface of the arm portion

83

a

of the third electrode

83

, and it is avoided for the both plate surfaces to be opposed to each other, whereby a capacitance is prevented to the utmost from being induced between the electrode plate

22

and the arm portion

83

a

. Also, as shown in

FIG. 5

, the plate surface of the electrode plate

23

and the plate surface of the electrode plate

22

are disposed so as not to be opposed to each other and further, the two electrode plates

22

and

23

are disposed in the developing frame

13

and the toner container

11

, respectively, to thereby prevent capacitance from being induced between the two electrode plates

22

and

23

.

That is, in the process cartridge B, the electrode plate

26

for wiring is provided on the developing frame

13

, whereby it is avoided for the electrode plate

22

on the voltage-application side and the electrode plate

23

on the output side to be disposed on the same frame and further, the induction of capacitance is prevented to thereby prevent the lowering of the accuracy of toner-remaining-amount detection.

On a side of the process cartridge B assembled as described above, the external contacts

22

a

and

23

a

of the second detecting means are disposed side by side in proximity to each other with the coupled surface of the developing frame

13

and the toner container

11

as the boundary, as shown in FIG.

6

. Also, as shown in

FIG. 7

, electrical contacts

30

and

31

are provided in the image forming apparatus A′ corresponding to the external contacts

22

a

and

23

a

, respectively. These electrical contacts

30

and

31

are attached to a contact holder

32

and are made into an integral contact unit

33

, which is incorporated in the frame of the main body of the image forming apparatus A′.

When the process cartridge B is inserted in the direction indicated by the arrow X and is mounted to the main body of the image forming apparatus A′, the external contacts

22

a

and

23

a

contact with and are electrically connected to the electrical contacts

30

and

31

, respectively, disposed in the main body of the image forming apparatus A′.

In the present invention, the external contacts

22

a

and

23

a

are disposed on the same side of the process cartridge B and in proximity to each other and therefore, the contact unit

33

provided in the image forming apparatus A′ can be made correspondingly small and the downsizing of the image forming apparatus A′ and a reduction in cost can be achieved.

Also, as shown in

FIG. 3

, the wire laying portions

36

and

37

of the wires from the contact unit

33

to the developer amount detecting circuit

200

can be made short, and the lowering of the accuracy of toner amount detection attributable to the irregularity of the capacitance between the wires can be prevented.

Further, in the present embodiment, the wiring of the electrodes is done in such a manner that the external contact

23

a

of the process cartridge B is provided in the developing frame

13

and the external contact

22

a

thereof is provided in the toner container

11

so that little or no capacitance exists between the arm portion

81

a

of the first electrode

81

which is a wire laying portion and the electrode plate

26

. Therefore, the irregularity of capacitance by the toner coming into the wire laying portion for the electrodes in the interior of the process cartridge B can be restrained, and this leads to an improvement in detection accuracy.

While in the present embodiment, the external contact

23

a

on the output side is disposed in the developing frame

13

and the external contact

22

a

on the input side is disposed in the toner container

11

, such disposition is not restrictive, but the external contact

23

a

can be disposed in one of the developing frame

13

and the toner container

11

and the external contact

22

a

can be disposed in the other of the developing frame

13

and the toner container

11

.

FIG. 8

is an exploded perspective view for showing the manner in which the antenna rod

89

, which is the first detecting means and the developing blade

18

are attached. As shown in

FIG. 8

, the antenna rod

89

is inserted into an aperture formed near a bearing for holding the developing roller

12

provided in the developing frame

13

, whereby it is directly attached to the developing frame

13

. At this time, the antenna rod

89

forms at least a straight line over a range in which the developing roller

12

exists, and is disposed substantially parallel to the developing roller

12

.

Also, the antenna rod

89

forms a crank-like shape and therefore, one end side thereof (this side as viewed in

FIG. 8

) is disposed so as to lie as an external contact

89

a

on the underside of the developing frame

13

, and is electrically connected to the electrical contact of the main body of the image forming apparatus A as the output contact of the first detecting means.

Also, the developing frame

13

is provided with a developing-frame attaching surface

13

L, on the opposite end portions of which there are provided positioning bosses

13

M. The developing blade

18

is fixed to the developing frame

13

by the positioning bosses

13

M being fitted into positioning apertures

18

a

formed in the opposite ends thereof, and small screws

43

being inserted into screw holes

18

b

and screwed into the internally threaded holes (not shown) of the developing frame

13

. As attaching means for each electrode, use can be made of screws, an adhesive agent, caulking, insert molding or the like.

While in the present embodiment, each electrode is made of a non-magnetic stainless steel material (SUS material) so as not to affect the circulation of the toner and is provided in the developing frame

13

, any electrode made of a non-magnetic material having chargeability, such as an aluminum material or electrically conductive resin, can be applied. It is also possible to subject the developing frame

13

to treatment such as vapor deposition or printing, and two-color-shape an electrically conductive paint layer, a vapor-deposited layer or electrically conductive resin directly provided on the frame to thereby form an electrically conducting portion In this case, as compared with a case where an electrode comprising a discrete member is attached, attachment tolerance and part tolerance decrease and therefore, an improvement in positional accuracy can be achieved.

The process cartridge of the present embodiment, as described above, is provided with two developer amount detecting means, whereby it can cope with any of the main body of the image forming apparatus A′ of a type having a mechanism for successively detecting the amount of toner and the main body of the image forming apparatus A having no successively detecting mechanism and effecting only the detection of the absence of the toner.

(Description of the Mounting of the Process Cartridge to the Image Forming Apparatus)

Reference is now made to

FIGS. 11

to

13

to describe a method of mounting the process cartridge B to the image forming apparatus A for the electrode rod detection type. The image forming apparatus A is an electrophotographic image forming apparatus corresponding to a process cartridge of the electrode-rod-detection type that detects the toner-absent state by an antenna rod. The image forming apparatus A is provided with a toner-presence-or-absence detecting circuit (mechanism) for detecting the presence or absence of the toner in the main body thereof.

FIG. 13

is a schematic view showing the longitudinal cross-section of the image forming apparatus A in a state in which the process cartridge B of the present invention is mounted thereto. The image forming apparatus A is substantially similar in construction to the image forming apparatus A′ shown in FIG.

1

and therefore, the similar portions thereof are given the same reference characters and need not be described. The image forming apparatus A is substantially similar in construction to the image forming apparatus A′ with the exception that it has a two-stage feed cassette

3

a

at the bottom of the main body thereof and the fixing means

5

comprises a driving roller

5

c

and a fixing roller

5

b

containing a heater

5

a

therein.

FIG. 11

is a perspective view showing the opening-closing member

35

of the image forming apparatus A as it is opened. Whereas shown in

FIG. 11

, the opening-closing member

35

is opened about a hinge

35

a

(see FIG.

13

), forwardly descent left and right guide rails

26

L and

26

R (

26

R being not shown) are seen on the left and right inner walls of the image forming apparatus A. As shown in

FIG. 12A

, left and right cylindrical guides

8

a

, coaxial with the photosensitive drum

7

, and an elongate posture determining guide (not shown), behind the cylindrical guides

8

a

as viewed in the direction of mounting of the process cartridge B to the main body of the apparatus, are inserted into the guide rails

26

L and

26

R, and the cylindrical guides

8

a

are fitted into the positioning grooves

26

bL and

26

bR (

26

bR being not shown) of the image forming apparatus A, whereby the process cartridge B is mounted to the image forming apparatus A.

When conversely, the process cartridge B mounted to the image forming apparatus A is to be detached, the process cartridge B is pulled out along the guide rails

26

L and

26

R by a procedure converse to what has been described above.

When the process cartridge B is mounted to the image forming apparatus A, the external contact

89

a

provided on the process cartridge B contacts the detection contact

126

of the main body of the image forming apparatus A, and the external contact

89

a

and the detection contact

126

are electrically connected together. As shown in

FIG. 12A

, the external contact

89

a

is disposed so as to lie on the underside of the process cartridge B, and the detection contact

126

is an electrically conductive leaf spring member provided below and beside the guide rail

26

L. The detection contact

126

is disposed at the bottom of a mount portion on which the process cartridge B is mounted when the opening-closing member

35

of the image forming apparatus A is opened (see FIG.

11

), and is adapted to be biased toward the external contact

89

a

lying on the underside of the process cartridge B by the leaf spring. The detection contact

126

is connected to the toner-remaining-amount detecting mechanism of the main body of the image forming apparatus A, and detects the remaining amount of toner in the process cartridge B by an electrical signal from the external contact

89

a

. Further, by the electrical signal from the external contact

89

a

, it detects whether the process cartridge B is mounted to the main body of the image forming apparatus A. This electrical signal is an electrical signal conforming to the capacitance produced between the antenna rod

89

and the developing roller

12

.

Also, as shown in

FIG. 12A

, on the left and right sides of the cylindrical guide

8

a

of the process cartridge B, there are provided an electrically conductive charging bias contact

120

electrically connected to the shaft of the charging roller

8

to apply a charging bias from the main body of the image forming apparatus A to the charging roller

8

, and an electrically conductive developing bias contact

12

a

electrically connected to the developing roller

12

to apply a developing bias from the main body of the image forming apparatus A to the developing roller

12

. On the other hand, on the front and rear sides of the positioning groove

26

bL of the main body of the image forming apparatus A, there are provided a charging contact member

124

and a developing contact member

103

correspondingly to the charging bias contact

120

and the developing bias contact

12

a

, respectively. The charging contact member

124

and the developing contact member

103

are biased toward the charging bias contact

120

and the developing bias contact

12

a

, respectively, by compression springs

129

as shown in FIG.

12

B.

When the process cartridge B is mounted to the image forming apparatus A corresponding to the developer amount detecting means provided by the antenna rod

89

, the first to third electrodes

81

,

82

, and

83

, which are the second detecting means do not function. That is, in the main body of the image forming apparatus A, there are not provided an electrical contact corresponding to the external contact

23

a

connected to the first and third electrodes

81

and

83

and an electrical contact corresponding to the external contact

22

a

connected to the second electrode

82

. Therefore, the external contacts

22

a

and

23

a

are not electrically connected to the main body of the image forming apparatus A. Accordingly, when the process cartridge B of the present invention is mounted to the main body of the image forming apparatus A, the first detecting means, which is the developer amount detecting means provided by the antenna rod

89

functions to produce in the image forming apparatus A an electrical signal for indicating of the presence or absence of the remaining amount of the toner and as to whether the process cartridge B is mounted.

Reference is now had to

FIG. 7

to describe a method of mounting the process cartridge B to the image forming apparatus A′.

The image forming apparatus A′ is an electrophotographic image forming apparatus corresponding to a process cartridge of the electrode-plate-detection type that detects the remaining amount of toner by an electrode plate. The image forming apparatus A′ is provided with a developer-amount detecting circuit for successively detecting the remaining amount of toner in the main body thereof.

FIG. 7

is a perspective view showing the opening-closing member

35

of the image forming apparatus A as it is opened.

Like the image forming apparatus A, the opening-closing member

35

is opened about a hinge

35

a

, and left and right cylindrical guides

8

a

coaxial with the photosensitive drum

7

and elongate posture determining guides (not shown) behind these cylindrical guides

8

a

as viewed in the direction of mounting of the process cartridge B to the main body of the apparatus are inserted into guide rails

26

L and

26

R, and the cylindrical guides

8

a

are fitted into the positioning grooves

26

bL and

26

bR (

26

bR being not shown) of the image forming apparatus A′ to thereby mount the process cartridge B to the image forming apparatus A′. When the process cartridge B mounted to the image forming apparatus A′ is to be detached, the process cartridge B is pulled out along the guide rails

26

L and

26

R by the procedure opposite to what has been described above.

When the process cartridge B is mounted to the image forming apparatus A′, the external contacts

22

a

and

23

a

provided on the side of the process cartridge B contact the electrical contacts

30

and

31

, respectively, of the main body of the image forming apparatus A′, and the external contacts

22

a

,

23

a

and the electrical contacts

30

,

31

are electrically connected together. As shown in

FIG. 7

, the electrical contacts

30

and

31

are attached to a contact holder

32

and are connected to the developer amount detecting circuit

200

in the main body of the image forming apparatus A′. Also, the contact holder

32

is disposed on the side wall of a mount portion on which the process cartridge B is mounted when the opening-closing member

35

of the image forming apparatus A′ is opened. The image forming apparatus A′ successively detects the remaining amount of toner in the process cartridge B by electrical signals from the external contacts

22

a

and

23

a

. Further, it detects whether the process cartridge B is mounted to the main body of the image forming apparatus A′ , by the electrical signals from the external contacts

22

a

and

23

a

. These electrical signals are electrical signals conforming to the capacitance produced between the first and third electrodes

81

and

83

and the second electrode

82

and the capacitance produced between the first and third electrodes

81

and

83

and the developing roller

12

.

When the process cartridge B is mounted to the image forming apparatus A′ corresponding to the developer amount detecting means provided by the electrode plate, the antenna rod

89

which is the first detecting means does not function. That is, an electrical contact corresponding to the external contact

89

a

of the antenna rod

89

is not provided in the main body of the image forming apparatus A′ and therefore, the external contact

89

a

is not electrically connected to the main body of the image forming apparatus A′. Accordingly, when the process cartridge B of the present invention is mounted to the main body of the image forming apparatus A′, the second detecting means provided by the first to third electrodes

81

,

82

and

83

function to produce in the image forming apparatus A′ an electrical signal indicating the remaining amount of toner and as to whether the process cartridge B has been mounted.

Also, according to the process cartridge B of the present invention, there is constructed an electrophotographic image forming system in which the process cartridge B is selectively mounted to the image forming apparatus A or the image forming apparatus A′ to thereby form an image on the recording medium

2

.

As described above, in the process cartridge B according to the present embodiment, the antenna rod

89

, which is the first detecting means, and the electrodes

81

,

82

and

83

, which are the second detecting means, are attached to the developing frame

13

and therefore, the process cartridge B has the interchangeability of being mountable to both of the electrophotographic image forming apparatus A of the electrode rod detection type and the electrophotographic image forming apparatus A′ of the electrode plate detection type.

To a user having both of the image forming apparatus A of the electrode rod detection type and the image forming apparatus A′ of the electrode plate detection type, it has heretofore been necessary to manage the remaining amounts of toner in the respective image forming apparatuses and have two kinds of process cartridges in stock. The process cartridge B of the present invention, however, makes it unnecessary to have two kinds of process cartridges corresponding to the respective image forming apparatuses in stock, and is convenient for management and excellent in usability.

The process cartridge B of the present embodiment is of such structure that one end (the external contact

89

a

) of the antenna rod

89

, which is the first detecting means, is disposed so as to lie on the underside of the cartridge and the external contacts

22

a

and

23

a

connected to the electrodes, which are the second detecting means, are provided on the side of the cartridge. As described above, the external contact

89

a

and the external contacts

22

a

,

23

a

are provided on the different surfaces of the cartridge and therefore, the external contacts

22

a

,

23

a

are prevented from contacting the detection contact

126

by mistake when the process cartridge B is mounted to the image forming apparatus A, and the external contact

89

a

is prevented from contacting with the electrical contacts

30

and

31

by mistake when the process cartridge B is mounted to the image forming apparatus A′.

Since in the present embodiment, all of the electrodes

81

,

82

and

83

providing the second detecting means are attached to the developing frame

13

, the accuracy of the intervals among the respective electrodes can be made good. Also, since all of the first to third electrodes

81

,

82

and

83

can be attached from the joined side of the developing frame

13

with the toner container

11

, the attachment efficiency is also good.

Further, by the first to third electrodes

81

,

82

and

83

being attached to the developing frame

13

and disposed near the developing sleeve

12

and the developing blade

18

, each electrode and the developing sleeve

12

and the developing blade

18

can be accurately positioned relative to one another, and the time when a blank area on an image is created can be detected accurately.

Also, by the antenna rod

89

as the first detecting means being attached to the developing frame

13

and disposed near the developing sleeve

12

and the developing blade

18

, the time when the developer is on the verge of depletion can be detected so that the time when a blank area on an image is created can be detected accurately.

While in the present embodiment, there has been shown the form of the process cartridge B in which the photosensitive drum

7

, which is an image bearing member, and the developing means

10

are constructed integrally with each other, of course, the present invention is not restricted to the process cartridge, but can also be applied to a developing device in which the developing means

10

, etc. are constructed as an integral developing unit

20

.

As described above, the main embodiment of the present invention is a process cartridge B detachably mountable to the main body of the electrophotographic image forming apparatus A and the main body of the electrophotographic image forming apparatus A′ differing in function from the main body of the image forming apparatus A, and having a photosensitive drum

7

, a developing roller

12

for developing an electrostatic latent image formed on the photosensitive drum

7

, a toner containing portion

14

containing therein a toner used to develop the electrostatic latent image by the developing roller

12

, and an antenna rod

89

disposed along the lengthwise direction of the developing roller

12

and having one end thereof (external contact

89

a

) exposed from a cartridge frame. Further, the process cartridge B has first, second and third electrodes

81

,

82

and

83

disposed along the lengthwise direction of the developing roller

12

, and the first and third electrodes

81

and

83

and the second electrode

82

are electrically connected to external contacts

23

a

and

22

a

exposed from the cartridge frame. When the process cartridge B is mounted to the main body of the image forming apparatus A, the external contact

89

a

is electrically connected to a detection contact member

126

provided in the main body of the image forming apparatus A. Then it produces an electrical signal for indicating that the process cartridge B has been mounted to the main body of the image forming apparatus A. Also, when the process cartridge B is mounted to the main body of the image forming apparatus A′, the external contact

89

a

is not electrically connected to the interior of the main body of the image forming apparatus A′. On the other hand, when the process cartridge B is mounted to the main body of the image forming apparatus A′, the external contacts

22

a

and

23

a

are electrically connected to electrical contacts

30

and

31

, respectively, provided in the main body of the image forming apparatus A′. Then, they produce an electrical signal for the main body of the image forming apparatus A′ to successively detect the remaining amount of developer. When the process cartridge B is mounted to the main body of the image forming apparatus A, the external contacts

22

a

and

23

a

are not electrically connected to the interior of the main body of the image forming apparatus A.

Also, the external contact

89

a

which is one end of the antenna rod

89

connected to the detection contact

126

and the external contacts

22

a

and

23

a

, which are the electrical contacts of the cartridge, connected to the first to third electrodes

81

,

82

and

83

are provided on the different surfaces of the cartridge frame. That is, the external contacts

22

a

and

23

a

which are the electrical contacts of the cartridge are disposed so as to lie on the side of the cartridge frame so that the external contact

89

a

may lie on the underside of the cartridge frame when the process cartridge B is mounted to the image forming apparatus A or A′.

According to the process cartridge of the above-mentioned embodiment, the antenna rod, which is the first detecting means, and the electrode plates which are the second detecting means are provided and therefore, the process cartridge can be mounted to both of an electrophotographic image forming apparatus of the electrode-rod-detection type and an electrophotographic image forming apparatus of the electrode-plate-detection type.

According to the above-described present invention, there can be provided a process cartridge detachably mountable to the main bodies of electrophotographic image forming apparatuses differing in function from each other, and an electrophotographic image forming system using the aforedescribed process cartridge.

While the invention has been described with reference to the structure disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.

Number	Name	Date	Kind
5923917	Sakurai et al.	Jul 1999	A
6021291	Karakama et al.	Feb 2000	A
6097909	Watanabe et al.	Aug 2000	A
6128452	Miyabe et al.	Oct 2000	A
6163665	Watanabe et al.	Dec 2000	A
6253036	Karakama et al.	Jun 2001	B1
6266500	Numagami et al.	Jul 2001	B1
6272299	Numagami et al.	Aug 2001	B1
6397018	Matsumoto et al.	May 2002	B1

Process cartridge and electrophotographic image forming system

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CPC

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Abstract

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Priority Claims (1)

US Referenced Citations (9)