JPH04186267A - Developing device - Google Patents

Abstract

PURPOSE:To prevent ununiformity and drop of density of developer even if a large quantity of the developer is supplied in a short time by arranging an opening and closing partition member between a developer reservoir and a developer mixer. CONSTITUTION:A developing device is roughly devided into a developer mixing portion (A) and a hopper portion (B) which serves as a developer reservoir. A shutter 8 is arranged between this mixing portion (A) and the hopper portion (B) as a partition member for preventing movement of the developer t. When the developer t is supplied, the shutter 8 closes completely the gap between the hopper portion (B) and the mixing portion (A), so, supply of a large quantity of the developer t to the developing sleeve 1, just after the supply, is prevented. After the supply, movement of the developer t becomes possible by pressing down the shutter 8, and a small quantity of the developer t is supplied successively toward the mixing portion (A) side with the rotation of a rotary bar 13.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an image forming apparatus such as an electrophotographic device or an electrostatic recording device, in which an image is formed on the surface of an image carrier such as an electrophotographic photoreceptor or an electrostatic recording dielectric. A developing device that develops a developed latent image into an image, particularly a developer carrier that carries and conveys a layer of developer in a developer storage section of the developing device to the surface of the image carrier to form a latent image into a single image; The present invention relates to a developing device including a developer supply section that supplies developer to a developer storage section and a developer agitation conveyance means that stirs the developer in the developer storage section.

[Prior Art] Conventionally, in image forming apparatuses that form images by electrophotography, for example, an eighth step is used to develop a latent image formed on an image carrier such as a photosensitive tram through a predetermined process.
A developing device as shown in the figure was used.

The current situation shown in this Figure 8! The device is composed of an agitating section A that holds a developing sleeve l as a developer carrier, and a hopper section B that accommodates a predetermined amount of developer and supplies it little by little to the agitating section A. A developer t is housed in this developing device, and this developer is a so-called -component magnetic powder (toner). This developer is supplied to the developing sleeve l disposed at the opening of the developer storage container 14, or the developing sleeve 71 has its right half-circumferential portion inserted into the developer storage container 14, and The developer storage container 14 is rotatably supported in such a manner that approximately half the peripheral surface thereof is exposed outside the developer storage container 14 . The developing sleeve 7l is made of a non-magnetic material such as aluminum or stainless steel, and is rotated by a drive system (not shown) in the counterclockwise direction indicated by the arrow at a predetermined circumferential speed.

A fixed magnet roller 2 as a magnetic field generating member is disposed inside the developing sleeve 1, and a fixed magnet roller 2 as a magnetic field generating member is disposed inside the developing sleeve 1.
is driven to rotate on the outside of the fixed magnet roller 2 concentrically with this magnet roller 2.

The circumferential surface of the fixed Macnet roller 2 is magnetized to form, for example, four magnetic poles 2a, 2b, 2C, and 2d at predetermined intervals. Among these magnetic poles, the magnetic pole 2a is a developing pole disposed on the side facing the image carrier 100 carrying a latent image, which will be described later, and the magnetic pole 2b is a developer layer thickness regulating member, which will be described later. There is a developer supply section (cut pole) arranged on the side corresponding to the lower part of the member 3,
The magnetic pole 2C and the magnetic pole 2d are developer transport poles arranged on the side facing the magnetic pole 2a and the magnetic pole 2b, respectively, in the fixed magnet roller 2.

Further, the blade member 3 (cutting blade/doctor blade) mentioned above faces the opening of the developer storage container 14 and hangs down from the side wall of the developer storage container 14 so as to be close to the developing sleeve l. Note that at this time, the blade member 3 may be made of a magnetic material or a non-magnetic material.

Further, a crank-shaped stirring section 4 is disposed at a predetermined position in the stirring section A so as to move the contained developer t toward the developing sleeve 7l one by one. The drive system (
(not shown) in the direction of the arrow (clockwise) shown in the figure.

The image carrier 100, such as an electrophotographic photoreceptor or an electrostatic recording dielectric, described above is of a drum type, and is driven to rotate at a predetermined circumferential speed in the direction of the arrow (clockwise) shown in the figure. , an electrostatic latent image is formed on the peripheral surface of the developing sleeve through a predetermined process by a latent image forming process device (not shown), and this latent image is transferred to the developing sleeve l by passing through a developing section.
Developed by

Note that a bias power source E for applying a developing bias between the developing sleeve 1 and the image carrier 100 is connected to the developing sleeve I.

In the above-described conventional developing device having such a configuration, the developer t in the developer storage container 14 is: (1) stirred by the rotation of the stirring rod 4; Rotation of the developing sleeve 1 in the developer reservoir ta on the half-circumferential side of the path, and rotation by creating a cyclical counterflow due to the magnetic field formed by the Macnet roller 2 inside this developing sleeve; The developer is charged with a triboelectric charge due to contact friction with the surface of the developing sleeve 71, and in particular, the developer near the surface of the developing sleeve 71 has a predetermined polarity and is charged with a sufficient amount of triboelectric charge.

Then, a part of the charged developer is sequentially held and supported magnetically and electrically as a developer layer on the circumferential surface of the rotating developing sleeve l, and is conveyed as the developing sleeve l rotates.
By passing through the blade member 3, the layer is formed into a thin layer with a predetermined thickness (thin layer coating), and the latent image on the image carrier 100 is developed by going around to the developing section A side facing the image carrier 100. The remaining developer layer that has not been subjected to development is transferred to the developer storage container 1 by the subsequent rotation of the development sleeve 1.
4.

On the other hand, a crank-shaped rotating rod 13 is disposed at a predetermined position in part B of the hopper so as to move the contained developer t toward the stirring section A.
is rotated by a drive system (not shown) in the direction of the arrow (clockwise) shown in the figure around an axis that is the central axis of rotation.

In addition, a detection means for detecting the remaining amount of developer t is placed in the hopper part B at a predetermined position, and it is determined whether the developer t in the hopper part B is consumed for development and needs to be replenished. When the developer t is released, the replenishment display lights up to indicate that the developer t should be replenished.

A supply port C is provided in the upper part of the hopper part B as an opening into which the developer t can be thrown, and a lid 12 is disposed on the supply port C to prevent the developer t from scattering. The lid 12 is configured to be openable and closable. When replenishing a developing device having such a supply port configuration, a cartridge type toner replenishment as shown in FIG. 9 is used.

In FIG. 9, one side of the toner cartridge container 15 is completely open. This opening is sealed by heat welding with a transparent release sheet 31 (shaded area in the figure), so that the developer t having a fine particle size does not leak outside from this heat welding part and contaminate the surrounding area. A filling port 32 is provided on the other side of the toner cartridge container 15 for filling the container with developer.

When replenishing the developing device with developer using such a toner cartridge, the following procedure is used (see FIG. 10).

After installing the toner cartridge with the release sheet 31 side aligned with the supply port C of the developing device, when the release sheet 31 is pulled, the release sheet 31 is peeled off from the heat-welded surface. The agent t falls under its own weight and is replenished into the hopper part B.

This replenishment method is as shown in FIG.
By sealing the joint between the toner cartridge container 15 and the toner cartridge container 15 using a soft elastic member 6 such as a sponge, contamination outside the machine can be prevented, and the operator can replenish the developer without getting his hands dirty. .

[Problems to be Solved by the Invention] However, in the above conventional example, when replenishing the developer, a large amount of the developer in the toner cartridge is replenished into the hopper section at once, so the developer with high fluidity is stored in the stirring section. A large amount of it flows into the developing sleeve. As a result, the proportion of developer with a lower charge amount than the residual developer in the stirring section, which had been stirred and used in the developing sleeve and stirring section, rapidly increased, resulting in a local uneven distribution of developer charge. This causes a difference in developing efficiency, resulting in uneven density and decreased density of the developer.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a developing device that does not cause density unevenness or density drop even when a large amount of developer is replenished at once.

[Means to solve the problem] According to the invention, the above objectives are achieved.

a developer storage container having a developer supply port at the top; a developer agitation conveyance means rotatably disposed inside the developer storage container to transport the developer forward while agitating the developer; A developing device comprising a developer carrier rotatably disposed at a front opening of a container and carrying the developer conveyed from the developer agitation conveyance means, the developer agitation conveyance means and the developer agitation conveyance means. A partition member is disposed at the communication opening between the means and the means for shielding the opening, and the partition member is engaged with a member external to the developer storage container or directly attached to the developer storage container. When the developer storage container is in a state where developer can be supplied, the communication opening is closed, and when the development operation is enabled, the communication opening is opened. achieved by being achieved.

[Function] The present invention separates the inside of the developing device into a developer storage section and a developer stirring section, and a partition member for moving the developer that can be opened and closed is provided between the storage section and the stirring section. The partition member is operated to be in a closed state only during replenishment. This prevents the developer from moving from the accommodating section to the agitating section.
Mass movement to or prevented from occurring.

As a result, it suppresses the local charge non-uniformity of the developer caused by the difference in the charge amount between the developer that has already been used and the newly replenished developer, and improves the density. To obtain a high-quality image that does not cause image unevenness such as unevenness and density reduction. Furthermore, high density and high image quality are ensured even after developer is replenished.

[Example] First to fourth embodiments of the present invention will be described based on the accompanying drawings.

<First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, the developing device is roughly divided into a developer stirring section A and a hopper section B, which is a developer storage section. First, the stirring section will be explained.

Reference numeral 1 denotes a developing sleeve which is a developer carrier that supplies developer facing a photosensitive drum (not shown) which is an image carrier, and is supported so as to be freely rotatable in the direction of the arrow.
.

The developing sleeve 71 is made of a non-i material such as stainless steel or aluminum, and a fixed Macnet roller 2, which is a magnetic field generation source, is arranged inside. A plurality of magnetic poles are magnetized on the circumferential surface of the fixed magnet roller, and the eighth
Similar to the conventional device shown in the figure, a developing pole 2a, a cutting pole 2b, and developer transport poles 2c and 2d are constructed. A flade member 3 or a developing sleeve 1 is disposed at a position opposite to the cut pole 2b so as to be close to the developing sleeve 1, and it controls the layer thickness of the developer on the developing sleeve l, and forms a developer reservoir part ta on the back side. As the developing sleeve l rotates, a pair of toner flows (arrows in the figure) are formed in a circular manner, causing frictional charging of the developer t.

An agitation unit 4 consisting of a crank-shaped rotating shaft for agitating the developer t supplied from the hopper part B and conveying the developer t to the developing sleeve 1 is disposed in the agitation unit A.
It is rotated clockwise in the figure by a drive source (not shown).

On the other hand, part B of the hopper is provided with an opening C at the top for replenishing developer from a cartridge-shaped toner container, similar to the conventional device shown in FIG.

Furthermore, in order to prevent the developer from scattering during use, there is a seal member 6 made of a soft elastic member such as a sponge to maintain airtightness around the entire circumference of the lid 12 and the opening C.

In the hopper part B, a rotating rod 13 is disposed as a developer stirring and conveying means consisting of a crank-shaped rotating shaft for sequentially replenishing the replenished developer to the stirring section, and a driving source (not shown) is provided. ) rotates clockwise to perform supply.

The purpose of actively supplying the developer t in the hopper part B
A plate sheet 7 made of an elastic material such as a urethane sheet is provided on the rotary rod 13 in order to avoid accumulation of water.

A shutter 8, which is a partition member, is provided between the stirring section A and the hopper section B to prevent the developer t from moving.

Next, an example of the configuration of the shutter 8 will be explained in detail based on FIG. 2.

The shutter 8 has a spring receiver at both ends with a part 8-2 and a long hole 8.
-3 is formed and engages with the pin lO of the shutter base 9 and the elongated hole 8-3 to define the guide function and sliding amount of the shutter 8. Further, the spring receiver receives the reaction force of the push-up spring 11 through the portion 8-2, so that the shutter 8 always receives an upward force.

The lid 12 has a shape that pushes down the shutter 8 by resisting this push-up spring, and in order to maintain the closed state, the developer storage container 14 has a recess 14-1, and the lid 12 has a convex portion 12-1. 1 is provided. Further, the shutter 8 is provided with an opening 8-1 through which the developer t passes. When the lid 12 is open, that is, when the opening 8-1 is in the state shown in the cross-sectional view of FIG.
2 is closed, when the lid 12 is engaged with the shutter 8 and pushed in, the shutter is pushed down, and the shutter is aligned with the opening formed by the opening 8-1 or the shutter stand 9 and the developer storage container 14. Thus, the developer t can be moved from the hopper part B to the stirring part A. That is, when replenishing the developer t, the shutter 8 completely blocks the space between the hopper part B and the stirring part A, so a large amount of the developer t immediately after replenishment is transferred to the development sleep l, which is a problem with the conventional device. It can be prevented from being supplied to the

When the lid 12 is closed after replenishment, as mentioned above, the shutter 8 is pushed down, allowing the agitating section A to move the developer between the hopper sections B, and as the rotary rod 13 rotates, a small amount of developer is released. The agent is sequentially supplied to the stirring section A side.

With this configuration, there is no change in the amount of developer in the stirring section A before and after the developer replenishment operation.

Therefore, it is possible to prevent the flow of the developer with a low charge amount in the cartridge container 15 to the developing sleeve l, thereby preventing the occurrence of image irregularities such as density unevenness and density reduction, and it is possible to always supply a stable image. become.

Second Embodiment Next, a second embodiment will be described based on FIG. 3. Note that since the difference from the first embodiment is the configuration of the means for moving the shutter 8, descriptions of the same names and functions will be omitted.

The shutter 8 has a splash catch 8-2 and an elongated hole 8-3 formed at both ends, as shown in FIG. However, the opening 8-1 is not open.

The pin 10 of the shutter base 9 and the elongated hole 8-3 engage with each other to define the guide function and sliding amount of the shutter 8. Further, the spring receiver receives the reaction force of the push-up spring 11 from the portion 8-2, so that the shutter 8 always receives an upward force.

The lid 12 has a shape that does not engage with the shutter 8,
Even when the lid 12 is closed, the shutter 8 is kept in contact with the upper side in normal use without pressing the shutter 8. The shutter 8 is attached to the cartridge container 15 when the supply is attached.
A push-down portion 15-1 is formed to engage with and push down the shutter 8, and as shown in FIG. 3, the shutter 8 is lowered to completely close the opening formed by the shutter stand 9 and the developer storage container 14. In this state, even when the replenishing release sheet shown in FIG. 9 is pulled and the developer t is dropped, there is no flow movement from the hopper part B to the stirring part A.

When the cartridge container 15 is released after replenishment, the shutter 8 is pushed upward by the push-up spring 11, so that the opening is exposed and the developer can be moved. As the rotary rod 13 rotates, only a small amount of the developer is sequentially supplied to the stirring section A side, and there is no change in the amount of developer t in the stirring section A before and after replenishing the developer.

Therefore, as in the conventional device, a large amount of developer with a low charge inside the cartridge is prevented from flowing into the stirring chamber.
It is possible to prevent image unevenness such as density unevenness and density reduction, and it is possible to always provide a stable image. The present invention is not limited to the above toner cartridge form.

<Third Embodiment> Next, a third embodiment will be described using FIG. 4. No.-
Duplicate parts in the description of names and functions that are the same as those in the embodiment and the second embodiment will be omitted.

In FIG. 4, reference numeral 100 denotes a photosensitive drum as an image carrier, which rotates clockwise as shown.

During image formation, the developing device is brought into contact with the photosensitive drum 100 with a predetermined gap formed by an abutting roller (not shown). When replenishing developer using a toner cartridge or the like in the developing device, the developer is pulled out of the machine, but if the photosensitive drum 100 is pulled out in the axial direction while still in contact with the developing device, the photosensitive drum 100 In order to damage the surface layer, it is usually pulled out at a distance.

In this embodiment, the developing device is mounted on a developing rail 16, and the developing rail 16 has a pressure spring 17 for ensuring contact force, an eccentric cam 19 that rotates around a shaft 18, and a release spring 20. By rotating the shaft 18, the developing device is moved toward and away from the photosensitive drum 100.

The shutter 8 has spring receivers 8- at both ends as shown in Fig. 2.
2 and an elongated hole 8-3 are formed, and the bin 10 of the shutter stand 9 and the elongated hole 8-3 fit together to define the sliding amount. Further, a guide plate 21 that engages with the upper slide cam 8-4 of the shutter 8 is fixed on the main body side, and the developing device is moved by rotating the shaft 18, and the slide cam 8-4 is attached to the kite plate 21. This results in the shutter 8 moving up and down. Therefore, the opening 8-1 of the shutter 8
moves up and down in conjunction with the separation operation of the developing device, stirring gl &
The opening amount of A and part B of the hopper changes.

That is, when the shutter 8 is operated in the contact direction F, the shutter 8 is lowered to coincide with the opening 8-1, and the developer t can be supplied from the hopper part B. Conversely, when the shutter 8 is operated in the separating direction G, the shutter 8 rises and closes the opening. When replenishing developer,
Since the above-mentioned separation operation must be performed, the developing device is in the state shown in FIG. 4, that is, the opening between the stirring section A and the hopper section B is completely blocked by the shutter 8. Therefore, even if developer is replenished using a cartridge container or the like, all of the developer that has fallen will remain in a portion of the hopper.

When setting the developing device, when the shaft 18 rotates and comes into contact with the photosensitive drum, the guide plate 21 and slide cam 8
-4 is engaged and lowered, so that the opening 8-1 and the opening coincide with each other, and the developer t can be supplied from a part of the hopper.

In this embodiment, as in the first and second embodiments, there is no change in the amount of developer t in the stirring section A before and after replenishing the developer.

Therefore, the occurrence of image irregularities such as density unevenness and density drop caused by large amounts of flow that occur when replenishing the developer as described in the conventional example can be prevented, and a stable image can always be supplied.

<Fourth Embodiment> Next, a fourth embodiment will be described using FIGS. 5 to 7. Same as the first to third embodiments - Overlapping parts in names and descriptions of functions will be omitted.

In FIG. 5, reference numeral 100 denotes a photosensitive tram, which rotates clockwise as shown. During image formation, the developing device is brought into contact with the photosensitive tram 100 via an abutting roller (not shown) to ensure a predetermined gap. When replenishing the developing device with developer, it is usually necessary to move it toward the front of the drawing and pull it out of the machine, or to pull it out while touching the photosensitive drum 1, as this will damage the photosensitive layer.
The structure is such that it is drawn out at a distance from 00.

In this embodiment, the shutter 8 is lowered in conjunction with the movement of pulling out the developing device parallel to the photosensitive drum axis, and the agitating section A
and close the opening of part B of the hopper.

The developing device is mounted on a developing rail 16, and the developing rail 16 is equipped with a pressure spring 17 that ensures contact force with the photosensitive tram 100, an eccentric cam 19 that rotates around a shaft 18, and a release spring 20. The developing device is configured to move toward and away from the photosensitive drum 100 by rotating the shaft 18.

The shutter 8 has a spring receiver 8-2 at both ends as shown in FIG. 6 and an elongated hole 8-3 as shown in FIG. The long holes fit together to provide a guide function and sliding amount. Further, guide pins 8-6 having different protruding directions are formed on the front and back sides of the upper part of the shutter 8 of this embodiment. Further, the developing rail 16 has a cam portion 16-1 that engages with the guide pin 8-6 and slides the shutter 8 downward.

As shown in FIG. 7, for the distance between the two guide pins, the slope J of the cam part 16-1, the distance intersection 2 between the starting points and the distance d between the end points, are all equal (intersection 1 = fL2=lz
), and the heights of the cams are the same, so when the developing device is inserted into the developing rail 16, the guide pin 8-6 and the cam part 1
6-1 is engaged, and the shutter 8 is pushed down in parallel at the same time in both directions. On the other hand, when the developing device is pulled out to put in the developer t, the pressed state of the guide pin 8-6 is released, and the shutter 8 or the push-up spring 11 raises it, closing the opening (see Figure 5). ). Therefore, when developer is replenished using a cartridge container or the like, all of the developer that falls remains in a portion of the hopper. When setting the developing device, when inserting it into the developing rail 16, the guide bin 8-6 and the cam portion 16-1 engage, and the shutter 8 is lowered, so that the opening 8-1 and the opening are aligned, and the developing device is inserted into the developing rail 16. The agent t can be supplied from the hopper.

In this embodiment, as in the first to third embodiments, there is no change in the amount of developer t in the stirring section A before and after replenishing the developer.

Therefore, it is possible to prevent the occurrence of image irregularities such as density unevenness and density drop due to a large amount of flow that occurs when replenishing developer as in conventional devices, and it is possible to always supply a stable image.

[Effects of the Invention] As explained above, according to the present invention, a movable member that can be opened and closed is provided in the opening between the developer agitation section and the developer storage section (hopper), and the movable member that can be opened and closed is provided in the opening between the developer stirring section and the developer storage section (hopper). movement (■
By opening and closing the replenishment lid, ■ Attaching and removing the cartridge, ■ Attaching and detaching the developing device, and closing the opening when replenishing the developer, the amount of charge is low. It is possible to prevent a large amount of developer in the cartridge from flowing into the stirring section, to ensure a stable toner charge amount, and to obtain a stable image without density unevenness, density reduction, etc.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a schematic configuration of a device according to a first embodiment of the present invention, FIG. 2 is a partially cutaway perspective view of the device shown in FIG. 1, and FIG. 3 is a schematic configuration of a device according to a second embodiment of the present invention. 4 is a sectional view showing a schematic configuration of a device according to a third embodiment of the present invention, FIG. 5 is a sectional view showing a schematic configuration of a device according to a fourth embodiment of the present invention, and FIG. Fig. 5 is a perspective view of the device, Fig. 7 is a diagram explaining the retaining operation of the partition member of the device in Fig. 5, Fig. 8 is a cross-sectional view showing the schematic configuration of the conventional device, and Fig. 9 is a conventional developer. FIG. 10 is a perspective view showing the replenishment container, and FIG. 9 is a perspective view showing the state in which the container is attached to the developing device. 1-------・Developer carrier (developing sleeve) 8----
--・Partition member (shutter) 13...Developer stirring and conveying means (rotary rod) 14...Developer storage container

Claims (5)

[Claims] (1) a developer storage container having a developer supply port in the upper part; a developer agitation conveyance means rotatably disposed inside the developer storage container to transport the developer forward while agitating the developer; A developing device comprising a developer carrier rotatably disposed at a front opening of a developer storage container and carrying the developer conveyed from the developer agitation conveyance means, the developer carrier and the developer A partition member is disposed at the communication opening between the developer agitation and conveyance means to shield the opening, and the partition member is a member attached to the outside of the developer storage container or directly to the developer storage container. When the developer storage container is in a state where developer can be supplied, the communication opening is closed, and when the developer storage container is in a state where a developing operation is possible, the communication opening is opened. A developing device characterized by being installed as follows. (2) having a lid for opening and closing the supply port; the partition member closing the communication opening when the lid is opened;
The developing device according to claim 1, wherein the developing device is attached so that the communication opening is opened when the lid is in a closed state. (3) The partition member is installed so as to close the communication opening when the developer supply container is attached to the supply port, and to open the communication opening when the developer supply container is separated from the supply port. developing device. (4) The developing device is arranged to be movable toward or away from the image carrier, and the partition member opens the communicating opening when the developing device approaches and opens the communicating opening when the developing device moves away. 2. The developing device according to claim 1, wherein the developing device is attached so as to close a portion of the developing device. (5) The developing device is disposed so as to be movable in parallel in the longitudinal direction of the image carrier, and the partition member closes the communication opening when the developing device is moved to the developer replenishment position, and is moved to the developing position. 2. The developing device according to claim 1, wherein the developing device is mounted so that the communication opening is opened when the developing device is opened.