JPH08286587A - Process cartridge - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a process cartridge which has good operability at the time of replenishment of the developer and good initial setting property of the developer, and which is surely stirred and conveyed by the developer. A process cartridge formed so that a developing unit 3 for visualizing an electrostatic latent image formed on a photosensitive drum 1 can be integrally disposed at a predetermined position. A developer preset unit 9 for enclosing the developer in the upper part of the developing unit is provided integrally with the process cartridge (upper cartridge case 11a), and between the developer preset unit 9 and the developing unit, A partition plate 10 for sealing the developer is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge of an image forming apparatus such as a copying machine, a printer and a facsimile which uses an electrophotographic system.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, and a facsimile which uses an electrophotographic system, there is often a problem that the developer is scattered in the developing unit when the developer is replaced. As a conventional technique aiming at solving such a problem, for example, two developer reservoirs are made independent and a special seal mechanism is provided at an opening thereof to further prevent the developer from scattering. A "developing device" which surely supplies a developer and obtains a good copy image (JP-A-60-95562). The other end of the double-folded seal member, one end of which is attached to the opening edge of the container, is provided on one end with a detachable winding member, and on the circumference of a winding roll pivotally supported on one side of the container. A "toner storage container" characterized by being supported (Japanese Utility Model Publication No. 61-117170). The developer transport path is a continuous developer circulation path including a forward path for sending the developer from the hopper and a return path for returning the developer sent to the forward path to the hopper, and is a continuous developer circulation path. "Developing device and image forming apparatus having the developing device", which is provided with a developing agent supply port which supplies a developing agent to the developing field through the developing section (JP-A-6-19303). Etc. are known.

On the other hand, in recent years, there has been proposed a process cartridge in which a developing unit for visualizing an electrostatic latent image formed on a photosensitive drum can be integrally arranged at a predetermined position. There is.

[0004]

However, the "developing device" described in the above-mentioned JP-A-60-95562.
However, since the sealant seals the developer in the developer cartridge, there is a problem in operability when the seal member is peeled off when the developer is replenished. Further, in the conventional "toner storage container" described in Japanese Patent Laid-Open No. 61-177170, as in the conventional example described above, the developer in the developer cartridge is sealed by a double-fold seal member, so that the developer is replenished. At this time, there is a problem in operability when winding the seal member. Further, the above-mentioned conventional Japanese Patent Laid-Open No. 6-19
The "developing device and an image forming apparatus having the same" described in Japanese Patent No. 303 is a typical example of a two-component developing device, and has a large agent capacity and a large number of parts, which increases the size and cost of the device. There is a defect.

On the other hand, in the above-mentioned conventional process cartridge, the developer cartridge (preset case) is formed as a separate body, and the developer is sealed by the same sealing member as in the above-mentioned conventional example. There was a problem in the operability (the initial setting property of the developer) when peeling off the seal member at the time of replenishing the agent, the cost of the parts was high, and the agitation and conveyance of the developer were unstable.

The present invention has been made in view of the above points, and an object thereof is operability at the time of replenishing the developer and good initial setting property of the developer, and stirring and transporting property of the developer. To provide a reliable process cartridge.

[0007]

In order to solve the above-mentioned problems, the present invention provides, in claim 1, a developing unit for visualizing an electrostatic latent image formed on a photosensitive drum. In the process cartridge formed so that it can be integrally disposed at the position, a preset unit for enclosing the developer is provided above the developing unit of the developing unit integrally with the process cartridge, and A partition plate for sealing the developer is provided between the preset unit and the developing unit.

According to a second aspect of the present invention, the partition plate is located above a developer stirring member including a first screw and a second screw arranged in the developing section of the developing unit.

According to a third aspect of the present invention, the partition plate rotates when the process cartridge is set in the main body of the image forming apparatus to supply the developer to the developing section.
The developer agitating member also serves as a partition plate between the first screw and the second screw.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows the appearance of the process cartridge of the present invention, and FIG. 2 shows a schematic cross section of the process cartridge.

In FIG. 2, the photosensitive drum 1 is
The charge is removed by the charge removing light, and the surface potential is averaged to a reference potential of 0 to -150V. Next, the photosensitive drum 1 is charged by the charging roller 2a of the charging unit 2 and the surface potential becomes around -1100V. When this photosensitive drum 1 is exposed by the exposure means 15, the surface potential of the portion (image portion) irradiated with the light becomes 0 to -290V,
To the image portion (electrostatic latent image), the toner on the developing sleeve 3a of the developing unit 3 to which a bias of about -800V is applied adheres, and the electrostatic latent image is formed into a toner image.

Next, the photosensitive drum 1 on which the toner image is formed is rotated and moved, and the transfer paper 13 fed from a paper feed unit (not shown) during this period has a transfer paper leading end and an image leading end transferred to the transfer separation unit 5. The transfer roller 5a is conveyed by the registration roller 14 at the same timing so that the toner image on the photosensitive drum 1 is transferred onto the transfer paper 13 by the transfer roller.

The transfer paper 13 on which the toner image has been transferred is sent to a fixing unit (not shown), and the toner image is melted and fixed on the transfer paper 13 by heating and pressurizing by a fixing means, and then a paper discharge tray outside the machine. Ejected as a copy on top.

On the other hand, the residual toner remaining on the photoconductor drum 1 is scraped off by the cleaning blade 6a of the cleaning unit 6, and the photoconductor drum 1 initialized by this is moved to the next image forming step again.

Here, the above-mentioned photosensitive drum 1, charging unit 2, developing unit 3, and cleaning unit 6 are integrally formed as a cartridge case 11 of a process cartridge so as to surround the photosensitive drum 1. Each is stored inside. As shown in FIG. 1, the cartridge case 11 is composed of an upper cartridge case 11a and a lower cartridge case 11b, and the residual toner collected by the cleaning unit 6 is transferred to the toner carrier as shown in FIG. By the coil 6b, the recycle belt 1 is sent to the recycled toner carrying section 11c formed on the front side of the cartridge case 11, and is disposed in the recycled toner carrying section 11c.
2, the developing agitator 11d of the cartridge case 11
The toner is sent to and recycled.

As described above, in this process cartridge, since the recycled toner carrying portion 11c is integrated with the cartridge case 11, there is no fear of toner leakage at the joining portion when these are separated, and this toner It is not necessary to add a sponge member for preventing leakage. Further, since the disposing portion of each unit is integrated, the assembling property of each unit is also improved.

The charging roller 2a of the charging unit 2 is constructed by winding a conductive rubber around the outer circumference of a metal cored bar,
The photosensitive drum 1 is contacted during the charging operation. The charging roller 2a is provided for the photosensitive drum 1 when the apparatus is stopped.
When left in contact with the photoconductor for a long time, the photosensitive drum 1
Is likely to be contaminated and an abnormal image may be generated. Therefore, when the apparatus is stopped, it is separated from the photosensitive drum 1.

Further, since the charging roller 2a during the charging operation is continuously in contact with the photosensitive drum 1, there is a possibility that the surface of the charging roller 2a may be contaminated with fine toner to cause uneven charging.
In order to prevent this problem, the charging unit 2
A cleaning pad 2b for cleaning the surface of the charging roller 2a is attached.

The contact / separation mechanism of the charging roller 2a is held in the charging roller case 2c through a bearing (not shown), and this bearing is movably mounted on the charging roller case 2c and is not shown. The charging roller 2a is pressed against the photosensitive drum 1 with a constant pressure by a compression spring.

The charging roller case 2c is constructed so as to be pushed upward by a compression spring (not shown). The charging roller case 2c is lifted together with the cleaning pad 2b and the charging roller 2a, and the charging roller 2a is moved to the photosensitive drum 1.
Can be separated from.

Three positions of the charging roller 2a, that is, an operating position where the charging roller 2a comes into contact with the photosensitive drum 1 to perform a charging operation,
The cleaning position where the charging roller case 2c is pushed down to bring the cleaning pad 2b into contact with the charging roller 2a and the separation position where the charging roller case 2c is pushed upward to separate the charging roller 2a from the photosensitive drum 1 are the contact points of the charging roller. The operation position of the separation arm (not shown) is determined, and the operation position of the charging roller contact / separation arm is determined by a contact / separation cam (not shown).

The contacting / separating cam is integrally mounted on a rotating shaft of an electromagnetic clutch (not shown). When the electromagnetic clutch rotates 120 ° in one operation, the charging roller 2a rotates by 120 °. Can be displaced to the above three positions.

By adopting the charging roller 2a having such a structure, the ozone generation amount can be reduced to 1/100 to 1/1000 as compared with the case of using the conventional corona charger, and the ozone treatment member can be used. Is unnecessary.

In the developing casing of the developing unit 3 formed integrally with the lower cartridge case 11b, a two-component developer in which a carrier made of small iron balls and toner are mixed is contained. The stored developer is supplied to the developing sleeve 3a while being circulated and stirred in the developing casing by the agent stirring member including the first screw 3c and the second screw 3d. A doctor blade (agent regulating member) 3b for regulating the layer thickness of the developer supplied onto the developing sleeve is provided near the outer periphery of the developing sleeve 3a.

On the other hand, the toner concentration (ratio of carrier to toner) in the developer in the developing casing is detected by the concentration detection sensor 16 including the magnetic permeability measuring sensor shown in FIGS. When the toner density becomes equal to or lower than the reference density, based on the detection signal of the density detection sensor 16,
Toner supply portion 4a provided in front of the developing unit 3
Then, the shortage toner is replenished from the toner bottle 4b of the toner replenishing unit 4 through the toner replenishing port 4c.

Further, a portion of the peripheral surface of the developing sleeve 3a facing the photosensitive drum 1 is exposed from the developing casing, and the exposed portion of the developing sleeve 3a is provided on the upstream side in the rotational direction of the developing sleeve 3a in the longitudinal direction thereof. An inlet seal 17 made of mylar or the like is provided to prevent the toner from scattering outside the developing casing. Further, side seals for preventing toner and the like from scattering from the end portions are also provided at the front and rear ends of the exposed portion.

Here, the developing sleeve 3a has a diameter of 16 to
The surface is formed of a rotatable aluminum cylinder of about 20 mm, and the surface thereof is smooth or is formed in a concavo-convex shape (for example, V groove) in order to improve the transportability of the developer. Further, in the developing sleeve 3a, five magnets are arranged so as not to rotate along the inner circumferential direction thereof,
It is configured such that a predetermined magnetic force distribution appears in the normal direction.

The doctor blade 3b is the developing sleeve 3
With respect to a, it has a configuration that can be adjusted in a substantially normal direction.
That is, at one end of the developing sleeve 3a, there is provided a supporting member that has a function of determining the rotation direction of the magnet provided in the developing sleeve and that supports the doctor blade 3b in an adjustable manner. At the opposite end, there is provided a support member having a function of a bearing for receiving the rotation of the developing sleeve 3a and a bearing for pressurizing and supporting the doctor blade 3b. As a result, the doctor blade 3b is adjusted and moved in the normal direction of the developing sleeve 3a via these supporting members, so that the gap between the doctor blade 3b and the developing sleeve 3a is adjusted, and the developer on the developing sleeve is adjusted. Layer thickness is adjusted. The gap between the doctor blade 3b and the developing sleeve 3a can be adjusted from the outside of the developing unit 3.

The first screw 3c and the second screw 3d as the agent stirring member are respectively elliptical plate shaped screws. The second screw 3d has a screw shape that receives the toner supply from the end and conveys the toner into the developing unit 3.
It is formed in a shape in which a part of an elliptical plate that conveys the developer from inside to inside while stirring is conveyed inside. Also, the first
Between the screw 3c and the second screw 3d, there is provided a partitioning part which is integral with the developing casing, and the front side and the back side of this partitioning part connect the first screw 3c and the second screw 3d. Each passage is provided.
As a result, the first screw 3c becomes the second screw 3c.
The developer sent to the back side by d is stirred and conveyed to the front side, and the developer on the developing sleeve 3a is collected and supplied. Like the second screw 3d, the first screw 3c has a shape in which a part of an elliptical plate is cut out.

To replenish the toner in the developing unit 3, when the toner concentration in the developer becomes lower than the reference concentration and the concentration detecting sensor 16 detects this, the toner bottle 4b of the toner replenishing unit 4 is detected based on this detection signal. The electromagnetic clutch of the bottle drive shaft for rotating the toner is turned on, whereby the toner bottle 4b is rotated, and the toner replenishment portion 4a provided in front of the developing unit 3 is supplied with the insufficient toner through the toner replenishment port 4c. It is done by being replenished.

Here, as shown in FIG. 1, the toner bottle 4b is provided with a spiral protrusion inside thereof, and the toner in the bottle is sequentially transferred from the back side to the front side by rotating the bottle drive shaft. It is configured to be sent to the toner discharge port on the side. Since the amount of toner discharged from the toner bottle 4b is not constant, the replenishment toner discharged from the toner bottle 4b is temporarily accumulated in the toner replenishment section 4a formed at the end of the developing casing. The toner replenishing unit 4a serves as a buffer, and the replenishment toner accumulated in the toner replenishing unit 4a is the toner replenishment mylar 4d.
By rotating the replenishment shaft of, the small refill shaft 4a and the second screw 3d pass through a small hole (diameter 0.5 to 1 mm) of a small hole mylar into the developing unit 3 little by little. A fixed amount is supplied.

By the way, in the conventional integrated cartridge (at least the photosensitive drum 1 and the developing unit 3 are integrated), the one-component (only toner and no carrier) developing method is mainstream. When the toner is adhered from the developing roller (developing sleeve) to the photosensitive drum, there is no medium such as a carrier in the two-component developing system, so that the developing roller and the photosensitive drum are separated by 0 to 0.3.
It is necessary to make it close to a minute distance such as mm.
Therefore, in such a conventional integrated cartridge, when the toner is recycled as in the above embodiment and the parts such as the waste toner tank are to be removed, the gap between the photosensitive drum and the developing roller is Since the width is small, foreign matter such as paper dust mixed in the recycled toner collected by the cleaning unit of the photoconductor drum is likely to be caught between the photoconductor drum and the developing roller. For this reason, it is not suitable to recycle toner in the conventional one-component developing type integrated cartridge because an abnormal image such as white stripes is likely to occur due to foreign matter being caught between the photosensitive drum and the developing roller. Is. Although there is a developing unit configured to carry out toner recycling by a one-component developing method, in the case of a conventional developing unit of this type,
The unit life is short, around 10K in copy count.

On the other hand, in the process cartridge of this embodiment, the developing system is a two-component developing system, so that the gap between the photosensitive drum and the developing roller can be set to 0.5 mm or more. Therefore, even if the toner is recycled, foreign matter such as paper dust mixed in the recycled toner will not be caught between the photoconductor drum and the developing roller, and the unit life and the number of copies It can be extended to more than 30K sheets.
Therefore, according to the present embodiment, compared to the above-described one-component developing method, the cost for the carrier is increased, but the unit life is extended more than twice, so that the total cost is reduced and the replacement interval is extended. The maintenance cost is also reduced.

The cleaning blade 6a of the cleaning unit 6 is formed of a flat polyurethane rubber or the like, and is fixed to a metallic blade holder with an adhesive or a double-sided tape. The position of the blade holder in the direction parallel to the inclined surface is regulated by two positioning pins provided on the inclined surface formed on the case around the photosensitive drum, and the blade holder faces the rotational direction of the photosensitive drum. , Is fixed to the case around the photosensitive drum with screws in the so-called counter direction. The position of the screw is in the same direction as the attaching surface of the cleaning blade 6a, and the blade holder is completely adhered to the inclined surface formed on the case around the photosensitive drum so that the blade holder learns from the inclined surface. The position in the direction perpendicular to the inclined surface is regulated.

As described above, the contact angle and pressure of the cleaning blade 6a with respect to the photosensitive drum 1 are completely ensured, and defects such as defective cleaning and abnormal noise are prevented. Further, in the configuration of the case around the photoconductor drum, the position of the screw for fixing the blade holder in the thrust direction is preferably located further outside than both ends of the photoconductor drum 1 including the flange. As a result, only the cleaning blade 6a can be replaced without removing the photoconductor drum 1.

The toner scraped off by the cleaning blade 6a is sent to the front side in FIG. 2 by the toner carrying screw 6b of the cleaning unit 6.
The toner conveying screw 6b has a gear engaged in the D hole on the inner side thereof, and the gear is meshed with the gear integrally formed with the flange of the photosensitive drum 1 so that the rotational drive is transmitted. Has been done.

A pin for driving the toner recycling belt 12 is provided on the front side of the toner conveying screw 6b so as to enter the elongated hole provided in the toner recycling belt 12. The other end of the toner recycling belt 12 is supported by a belt driven roller which is fixed at a predetermined position by the photosensitive drum surrounding case.
A predetermined tension is applied to the toner recycling belt 12.

The toner discharged from the cleaning section by the toner conveying screw 6b passes through an elongated hole provided in the toner-diseased area belt 12 while being unstablely moved in the vicinity of the transfer section with the toner recycling belt 12. The toner recycle belt 12 is conveyed to the developing unit 3 by the fin portion.

The transfer roller 5a of the transfer separation unit 5 is
It is formed by winding a conductive resin around a metal core bar,
The bearing together with the bearing is pressed toward the photosensitive drum by a compression spring (not shown). The toner image on the photosensitive drum 1 is transferred to the transfer paper 13 by applying a constant current to the transfer roller 5a. This transfer roller 5a
Is configured so that it can be brought into contact with and separated from the photoconductor drum 1 by a mechanism similar to that of the charging roller 2a.

A static elimination needle 5b is arranged on the downstream side of the transfer roller 5a. The static elimination needle 5b is made of a thin metal plate, and the tip of the protrusion on the side facing the photosensitive drum 1 is
It is formed in a serrated shape with sharp edges. The charge removal needle 5b removes the electric charge charged on the transfer paper 13 by applying a voltage from a power source (not shown), and assists the separation of the transfer paper 13 from the photosensitive drum 1.

By the way, the cartridge case 11 of the process cartridge according to the present invention is provided with the developer preset portion 9 as shown in FIG. The developer preset portion 9 is formed in a container shape integrally formed (or attached) with the upper cartridge case 11 a of the cartridge case 11. A part of the upper cartridge case 11a of the developer preset portion 9 is provided with a developer sealing port. Further, an opening portion is provided below the upper cartridge case 11a of the developer presetting portion 9, and the opening portion is formed by the partition plate 10a.
It can be sealed by. Here, the partition plate 10 closes the opening of the upper cartridge case 11a as shown in FIG. 6A when the developer is enclosed in the developer preset portion 9 (preset state). Located in a substantially horizontal posture, the developer is sealed in the developer preset portion 9 to prevent the developer from dropping into the developing unit 3.

This process cartridge has a partition plate 10
Is set in the main body of the apparatus while being in the preset state. When the partition plate 10 is rotated clockwise (or counterclockwise) by about 90 ° by either manual or automatic operation with the process cartridge set in the apparatus main body, the partition plate 1
0 is positioned in a substantially vertical posture as shown in FIG. 6B, and the upper cartridge case 1 of the developer preset unit 9 is
The opening of 1a is opened. As a result, the developer in the developer preset section 9 falls into the developing unit 3 due to its own weight, and the developing unit 3 is in an initial state in which development is possible.

Here, when the partition plate 10 is manually rotated, for example, a manual rotation knob is provided on the rotary shaft of the partition plate 10 on the front side of the upper cartridge case, and the partition plate is rotated by rotating the knob. Rotate 10. Also, the partition plate 10
In case of automatic rotation of, for example, the partition plate 1
A sector gear is provided on the rotary shaft on the back side of the upper cartridge case 0, and the partition plate 10 is rotated by transmitting the rotational drive of the first screw 3c or the second screw 3d of the developing unit 3. This allows
The partition plate 10 is held in a hold state after being rotated about 90 ° and is fixed in a predetermined posture.

Further, as shown in FIG. 6 (b), the partition plate 10 in this embodiment is rotated in a substantially vertical posture so that the first screw 3c and the second screw 3d of the developing unit 3 are separated from each other. Partition between (lower cartridge case 11
The lower end portion of the partition plate 10 is configured to overlap (part of b). As a result, in this embodiment, the developer transporting portion of the first screw 3c and the developer transporting portion of the second screw 3d of the developing unit 3 are separated by the partition portion and the partition plate 10.
Since it is reliably separated by, it is possible to prevent the mixing of the developer in an abnormal state due to overflow in the developer transporting section of the first screw 3c and the developer transporting section of the second screw 3d,
The developer can be stirred (mixed) and conveyed normally (normal state).

FIG. 7 shows a schematic structure of the partition plate 10 described above. In FIG. 7, the partition plate 10 is axially supported in the front-rear direction of the cartridge case 11a and is configured to be rotatable around the support shaft 10a. The bearing portion of the support shaft 10a of the upper cartridge case 11a is sealed by a seal member (not shown) to prevent the developer from scattering from the bearing portion.

As shown in FIG. 7 (a), the partition plate 10 has the above-mentioned knob 10b attached to the shaft end of a support shaft 10a which extends through the upper cartridge case 11a to the outside of the case. It is rotationally driven by manually or automatically rotating the sector gear 10c. Further, as shown in FIG. 7B, the partition plate 10 includes a plate-shaped portion 10 ′ made of a resin member formed integrally with the support shaft 10 a,
With the seal parts 10 ″ made of Mylar or the like attached to both sides of the plate part 10 ′, it is formed into a blade shape,
As a result, the sealing property of the developer in the preset state is maintained, and the rotation load when the rotation is applied does not increase.

[0047]

According to the present invention, in claim 1, since the developer is stored by the combination of the cartridge case and the partition plate, the component structure can be reduced and the cost can be reduced. Further, since the developer can be easily set up by rotating the partition plate, operability can be improved. Furthermore, since the developer is enclosed integrally with the process cartridge, it is possible to easily maintain the quality and control of the developer.

In the second aspect, since the center of rotation of the partition plate is located at the center of the first screw and the second screw above the developing agitation unit, the developer can be uniformly supplied into the developing unit. Further, since the front side of the developer supply port is limited by using the partition plate, excessive supply of the developer into the developing unit is prevented, the supplied developer is averaged as a whole, and the load applied to the screw is increased. Can be made smaller.

In the third aspect of the invention, the developer conveying portion of the first screw and the developer conveying portion of the second screw at the time of supplying the developer can be completely separated by the rotation of the partition plate, so that the developer overflows. Prevents abnormal mixing due to
The developer can be surely stirred and conveyed. Further, since the partition plate at the time of supplying the developer also serves as the partition portion of the lower cartridge case between the developer transporting portion of the first screw and the developer transporting portion of the second screw, the height of the partition portion of the lower cartridge case is increased. Since the lower cartridge case (resin part) can be easily formed, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a process cartridge of the present invention.

FIG. 2 is a schematic cross-sectional view showing the configuration of the process cartridge of the present invention.

FIG. 3 is a schematic plan sectional view showing a configuration of a developing unit of the process cartridge of the present invention.

FIG. 4 is a schematic side sectional view showing the structure of the developing unit of the process cartridge of the present invention.

FIG. 5 is a schematic perspective view showing the configuration of the lower case of the process cartridge of the present invention.

FIG. 6 is a schematic side sectional view showing a configuration of a developer preset portion of the developing unit in the process cartridge of the present invention.

FIG. 7 is a schematic view showing a configuration of a partition plate arranged in a developer preset portion of a developing unit in the process cartridge of the present invention.

[Explanation of symbols]

 1 Photoconductor Drum 2 Charging Unit 3 Developing Unit 3c First Screw 3d Second Screw 4 Toner Replenishing Unit 5 Transfer Separation Unit 6 Cleaning Unit 9 Developer Preset Section 10 Partition Plate 10 'Plate Section 10 "Seal Section 10a Spindle 10b Knob 10c Sector gear 11 Cartridge case 11a Upper cartridge case 11b Lower cartridge case 11c Recycled toner transport section 11d Developer stirring section 12 Toner recycle belt 13 Transfer paper 14 Registration roller 15 Exposure means 16 Density detection sensor 17 Entrance seal

Claims (3)

[Claims] 1. A process cartridge formed so that a developing unit for visualizing an electrostatic latent image formed on a photosensitive drum can be integrally arranged at a predetermined position. A partitioning plate for sealing the developer is provided above the developing unit in an integrated manner with the process cartridge, and a partition plate for sealing the developer between the preset unit and the developing unit. A process cartridge characterized by being provided. 2. The partition plate is located above a developer stirring member composed of a first screw and a second screw arranged in the developing section of the developing unit. Process cartridge. 3. The partition plate rotates when the process cartridge is set in the main body of the image forming apparatus to supply the developer to the developing section, and the first screw and the first screw of the developer stirring member. The process cartridge according to claim 2, which also functions as a partition plate between the two screws.