JPH04358177A - Developing device - Google Patents

Abstract

PURPOSE:To reduce the starting torque of an agitator at the time of setting a toner cartridge and the driving torque of the agitator at the time of replenishing toner. CONSTITUTION:The agitator 21 of the toner cartridge 18 is divided into a toner carrying plate 30 and a toner agitating plate 29 which can abut on the toner carrying plate 30 and has the transmission of rotating/driving force for agitating the toner. The carrying plate 30 and the toner agitating plate 29 are separately disposed in advance at the time of unusing and even when the toner is flocculated inside a cartridge main body, the flocculation is destroyed at the time of rotating the toner agitating plate 29. After that, the toner agitating plate 29 and the toner carrying plate 30 are rotated together.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a developing section having a developer carrier disposed opposite to a latent image carrier, a toner hopper section storing toner to be supplied to the developing section, and a toner hopper section containing toner. an opening through which the toner to be supplied to the developing section passes, and an agitator is provided in the toner hopper section to agitate the toner and to supply the toner to the developing section through the opening. The present invention relates to a developing device.

0002

2. Description of the Related Art Developing devices of the above type are well known and are used in image forming apparatuses such as copying machines and printers. Some developing devices of this type use a toner cartridge as a toner hopper.
When this toner cartridge is stored, the toner may aggregate and lose fluidity. When a toner cartridge containing agglomerated toner is set in a developing device and used, the starting torque becomes extremely large when attempting to rotate the agitator. Therefore,
A large load is placed on the joint between the agitator and the drive section, as well as on the drive section itself, sometimes resulting in damage to these parts.

Conventionally, this problem has been addressed by firstly devising the shape of the agitator, secondly increasing its strength, and thirdly having the user shake it thoroughly before wearing it.

0004

[Problem to be solved by the invention] Most of the above problems can be solved if the third user shakes the product thoroughly before wearing it, but no matter how many instructions are given in the manual or decals, etc. However, it cannot be expected that this work will be completed 100%. Also, the first
There is a limit to the shape of the agitator because the agitator is used for toner replenishment, and if the agitator is disposable, apart from increasing the second strength, the material cost will be limited. receive. moreover,
Even if the strength were increased, there was a problem in that the capacity of the drive motor would need to be reviewed.

In a developing device in which an agitator slides into an opening in a toner hopper section of a toner cartridge or the like to replenish toner to a developing section, when the agitator is rotated to replenish toner, an elastic member at the tip of the agitator is pressed not only against the opening but also against the inner wall of the cartridge body. For this reason, there is also the problem that it is inevitable that the drive torque of the agitator increases to some extent.

The present invention solves the above-mentioned conventional problems, and
It is an object of the present invention to provide a developing device that can reduce the starting torque of an agitator when setting a toner cartridge and the driving torque of an agitator when replenishing toner.

[0007]

[Means for Solving the Problems] The structure of the present invention to achieve this object is as follows.

(1) a developing section having a developer carrier disposed opposite to the latent image carrier; a toner hopper section storing toner to be supplied to the developing section; In the developing device, the toner hopper section is provided with an agitator that agitates the toner and supplies the toner to the developing section through the opening. The toner hopper section is configured as a toner cartridge,
The agitator of the toner cartridge is divided into a toner conveying member that conveys toner, and a toner agitating member that is engageable with the toner conveying member and that agitates the toner by transmitting rotational driving force, and is not in use. A developing device, wherein the toner cartridge is arranged such that the toner conveying member and the toner stirring member are separated from each other.

(2) a developing section having a developer carrier disposed opposite to the latent image carrier; a toner hopper section storing toner to be supplied to the developing section; In the developing device, the toner hopper section is provided with an agitator that agitates the toner and supplies the toner to the developing section through the opening. The agitator is configured to be in sliding contact with the opening to supply toner to the developing section, and with respect to the distance from the center of the agitator to the opening, there is a distance from the center of the agitator other than the opening to the toner hopper. A developing device characterized in that the distance to the inner wall of the developing device is set to be large.

(3) a developing section having a developer carrier disposed opposite to the latent image carrier; a toner hopper section storing toner to be supplied to the developing section; In the developing device, the toner hopper section is provided with an agitator that agitates the toner and supplies the toner to the developing section through the opening. The opening is a plurality of small holes, and the agitator is configured to replenish toner to the developing section by slidingly contacting the opening, and the conveying member at the tip of the agitator slidingly contacting the opening has a brush shape. A developing device characterized in that:

[0011]

[Operation] According to the configuration (1) above, the agitator is divided into a toner transporting member that transports toner and a toner stirring member that stirs toner that can be engaged with the transporting member. The drive is transmitted, and the toner conveying member and agitating member are placed apart from each other in an unused toner cartridge, so even if there is toner aggregation, this can be broken up by the toner agitating member, and when the agitator rotates due to toner aggregation. Torque can be significantly reduced.

According to the configuration (2) above, with respect to the distance from the center of the agitator at the opening of the toner hopper to the opening, the distance from the center of the agitator to the inner wall of the toner hopper at a location other than the opening of the toner hopper is Since the distance is set large, the agitator can be brought into sliding contact at the openings necessary for toner transport, and sliding contact can be eliminated or the sliding contact force can be reduced at areas other than the openings, and the torque during rotation of the agitator can be reduced.

According to the configuration (3) above, even if the agitator is brought into sliding contact with the opening necessary for toner conveyance, the conveying member at the tip of the agitator is formed into a brush shape, so that the torque during rotation of the agitator is reduced. can.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall schematic diagram showing an example of a laser printer using a developing device according to the present invention. In FIG. 1, recording paper 2 is fed from a paper feeder 1 in the direction of arrow A.
is conveyed to a latent image carrier consisting of a drum-shaped photoreceptor 4 in a timed manner by a pair of registration rollers 3. The photoreceptor 4 is rotationally driven in a counterclockwise direction, the surface of which is charged by a charging charger 5, and a laser optical system 6.
The photoreceptor is irradiated with laser light L to form an electrostatic latent image on the photoreceptor. This latent image is made visible by toner when passing through the developing device 7, and this visible image is transferred to the recording paper 2, which is conveyed to the photoreceptor 4 by the transfer/separation charger 8, and is brought into close contact with the photoreceptor 4. The recording paper 2 is electrostatically separated. Thereafter, the visible image is fixed on the recording paper 2 by the fixing device 9, and the recording paper 2 is conveyed in the direction of arrow B and discharged to the paper discharge section 10 on the printer main body 12. On the other hand, after the visible image has been transferred, the photoreceptor 3 is neutralized by a static eliminator 13 having an LED, residual toner is removed by a cleaning device 11, and the removed toner is collected by the cleaning device 11.

As shown in FIG. 2, the developing device 7 includes a developing roller 16 disposed facing the photoreceptor 4 in a casing 14 serving as a main body of the developing device, and a toner replenishing roller for replenishing the developing roller 16 with toner. 17 and developing roller 1
The developing unit 15 includes a developing unit 15 equipped with a doctor roller etc. that regulates the layer thickness of the toner supplied on the toner 6, and a toner cartridge 18 serving as a toner hopper unit storing mono-component toner. The toner cartridge 18 includes a cartridge main body 20 storing toner, an opening 19 formed in the cartridge main body 20 that communicates with the developing section 15, and an opening 19 for stirring the stored toner and supplying the toner to the developing section 15. The agitator 21 is also provided.

This toner cartridge 18 has an opening 1
9 facing upward, and rotate it counterclockwise to align the opening 19 with the toner replenishment position leading to the developing section 15. When the developing roller drive gear 22 is driven by the drive means of the laser printer (not shown), the drive is transmitted to the agitator gear 23 via the idler gears 23, 24, and 25, and the agitator 21 is clocked as shown in FIG. rotated in the direction Note that the idler gear 24 is drivingly connected to a doctor roller drive gear 27 via an idler gear 26. Then, when the agitator 21 is rotated,
The toner in the cartridge main body 20 is supplied to the developing section 15. The toner supplied to the developing section 15 is charged by a toner replenishing roller 17 and replenished onto a developing roller 16, and then formed into a uniform thin layer by a doctor roller 18. Then, the electrostatic latent image is developed by contacting the photoreceptor 4 or the like. Here, the toner is fed from the cartridge main body 20 to the developing section 15 by the agitator 21, and the amount of toner in the cartridge main body 20 and the developing section 15 is stabilized when the balance is achieved. Thereafter, as the printing operation continues and toner consumption progresses, the toner level gradually decreases, and when it falls below a certain level, image loss occurs. Therefore, it is necessary to detect the toner end and replace the toner cartridge 18 before image omission occurs. Note that 15a is a sensor that detects toner end.

When replacing the toner cartridge 18,
If the newly installed toner cartridge 18 is not shaken well by the user, the toner may aggregate. When the toner cartridge 18 in which the toner has aggregated is installed in the developing device 7 and used, a large force is required on the agitator 21 and its driving section, which may cause damage to the agitator 21 and its driving section. was explained earlier.

The present invention takes the following measures to solve the above problems. Toner cartridge 1
The agitator 21 of No. 8 includes a toner conveying plate 30 as a toner conveying member that conveys the toner to the tip side shown in FIG. It is divided into a toner stirring plate 29 as a toner stirring member to which driving force is transmitted. In this case, as shown in FIG. 5, the toner agitation plate 29 is configured as a plurality of rigid foot-like plates with a small area that contacts the toner, and the agitator shaft 29 is fixed to the agitator gear 23.
8 at appropriate intervals. On the other hand, the toner conveying plate 30 is formed into an elongated plate shape as shown in FIG. 4, and is fixed to the tip of a support frame 30a having legs rotatably attached to both sides of the agitator shaft 28. In this agitator 21, even if the toner stirring plate 29 and the toner conveying plate 30 are arranged apart from each other, when the agitator shaft 28 rotates, the toner stirring plate 29 rotates, and the tip 29 of each toner stirring plate 29 rotates.
When a comes into contact with the toner conveying plate 30, as shown in FIG. 6, the toner conveying plate 30 is pushed by the toner stirring plate 29, so that both members rotate together.

As shown in FIG. 7, in the toner cartridge 18 having such a structure, when not in use, the conveying plate 30 and the toner agitating plate 29 are placed apart from each other. It is preferable that the toner agitation plate 29 be placed slightly ahead of the plate 30. When this toner cartridge 18 is installed in the developing device 7 and the agitator 21 is driven to rotate, only the toner agitating plate 29 rotates approximately one revolution, and during this time the toner conveying plate 30 rotates.
remains stopped. When this toner agitation plate 29 rotates, even if toner agglomeration occurs within the cartridge body, it can be broken up. When the tip 29a of the toner stirring plate 29 comes into contact with the back surface of the toner conveying plate 30, the toner conveying plate 30 is pushed from behind thereby causing the toner stirring plate 29 and the toner conveying plate 30 to
and rotate together. At this time, since the aggregated toner is once broken up by the toner stirring plate 29, the toner conveying plate 30 can be rotated without being subjected to a large torque.

[0020] Thus, by breaking up the aggregated toner in advance by the toner stirring plate 29, a large load is not applied when the toner conveying plate 30 rotates, and damage to the agitator 21 and its driving portion can be prevented. Moreover, the toner stirring plate 2
Since the area of the plate 9 that contacts the toner is smaller than that of the toner conveying plate 30, a large torque is not applied even during initial driving when toner aggregates. Note that the toner stirring plate 29
As shown in FIG. 8, the agitator 21 may be tapered so that the front part in the rotational direction is small and the rear part is large. In this case, the area of the toner stirring plate 29 that contacts the toner can be made smaller, so that the A large stirring force can be obtained with a smaller torque. Further, although this embodiment is a developing device using a one-component toner, it can also be applied to a developing device using a two-component developer.

FIG. 9 shows another embodiment of the present invention, and this embodiment is a developing device 7 using a two-component developer, and has a cylindrical toner cartridge 18 as a toner hopper section. There is. The toner cartridge 18 is separate from the developing device main body casing 7a, and toner is prefilled in the toner cartridge 18 on the assembly line. Therefore, even in the developing device 7 using a two-component developer, toner filling becomes easy, and compared to a system in which toner is supplied to a toner hopper portion of the developing device main body, there is no toner scattering, which is advantageous.

The developing device 7, as shown in FIG.
Opening 1 leading to the developing section 15 of the toner cartridge 18
A small hole plate 31 is provided at 9, and small holes 32 are formed in the small hole plate 31 at appropriate intervals. The toner conveying plate 30 of the agitator 21 is brought into sliding contact with the small hole plate 31 to supply toner to the developing section 15. By the way, in this type of developing device proposed by the applicant, when the agitator 21 rotates, the toner conveying plate 30 is always in sliding contact with the inner wall of the cartridge main body 20, and a certain amount of torque is always applied to the agitator drive section. It is inevitable that this will occur. Although not shown in the drawings, this developing device uses a polyester film as the toner transport plate 30 of the agitator 21. However, since the polyester film is strong, the sliding force against the inner wall of the cartridge main body 20 becomes large, and the toner is supplied to the developing section 15 in an aggregated state. Therefore, if it takes time for the toner to be mixed with the developer, or if the aggregated toner is conveyed to the developing roller 16, it will not be sufficiently charged, resulting in background stains on the image.

Therefore, in the present invention, as shown in FIG. 9, the opening 1 where the small hole plate 31 is located is
9 is a, and the distance from the center of the agitator 21 to the inner wall of the cartridge body 20 other than the opening 19 of the cartridge body 20 is b, then the shape of the cartridge body 20 is such that distance a<distance b. Alternatively, the position of the agitator 21 is set. That is, from the center of rotation of the agitator 21 to the opening 19 where the small hole plate 31 is located.
The opening 1 of the cartridge body 20 with respect to the distance a to
The toner cartridge 18 is used such that the distance b from the center of the agitator 21 to the inner wall of the cartridge main body 20 at points other than 9 is large. In this example, the cylindrical cartridge body 20 has a linear surface portion 20 at its opening 19.
By forming distance a, it is configured such that distance a<distance b. In this case, the distance a is set to a distance that allows the amount of protrusion of the agitator 21 from the small hole plate 31 of the toner conveying plate 30 to replenish a good amount of toner from the small holes 32. Further, the distance b is preferably set to such a distance that the toner conveying plate 30 of the agitator 21 approaches the inner wall of the cartridge main body 20 but does not come into contact with it.
The distance may be such that the toner conveying plate 30 slightly touches the inner wall of the cartridge main body 20.

Thus, by setting the distance from the rotation center of the agitator 21 between the opening 19 where the small hole plate 31 is located and the other area as described above, when the agitator 21 rotates, the toner conveying plate 30 does not always come into sliding contact with the inner wall of the cartridge main body 20, and even if it does come into sliding contact, the sliding contact force is very small, so that it is possible to prevent a certain amount of torque from always being applied to the agitator drive section. Therefore, a small motor can be used to drive the agitator, which is effective in downsizing the device and saving labor.

FIG. 10 shows a modification of the above embodiment, in which the opening 19 with the small hole plate 31 is located from the center of rotation of the agitator 21.
The opening 1 of the cartridge body 20 with respect to the distance a to
In order to increase the distance b from the center of the agitator 21 to the inner wall of the cartridge body 20 at points other than 9, the center of the agitator 21 is offset from the cartridge body 20 in the direction closer to the opening 19. Even with this configuration, the same effects as in the above embodiment can be obtained.

Furthermore, in the present invention, as shown in FIGS. 11 and 12, a toner conveying brush 33 is used instead of the toner conveying plate 30 as a toner conveying member of the agitator 21,
The toner is replenished by the elastic force of the brush. The toner conveying brush 33 is made of, for example, SUS316 brush material, strand diameter 12 μm, and flocking pitch 0.
．． Two pitches and a flocking density of 100 F/mm are used.

The developing device 7 having such a structure is advantageous in terms of image quality and torque compared to the developing device that uses a polyester film as the toner transport plate 30 of the agitator 21 proposed by the applicant of the present invention, and has advantages in both image quality and torque. We will explain in detail the differences in the effects using experimental data.

The developing device 7 shown in FIG. 12 is used,
A polyester film having a thickness of 0.1 mm is used as the small hole plate 31, and 33 small holes 32 each having a diameter of 0.7 mm are formed in this small hole plate 31. The toner conveying brush 33 is
The experiment was conducted using the above-mentioned brush material SUS316 with a wire diameter of 12 μm, a flocking pitch of 0.2 pitch, and a flocking density of 100 F/mm, and a polyester film with a thickness of 0.075 mm as the toner transport plate 30.

In the device using the toner conveying plate 30, the polyester film is rubbed against the inner wall of the cartridge body 20 and the inside of the small hole plate 31 to replenish toner, so that the toner is aggregated in the developing section 15. is replenished with
It has accumulated in section C of the developing section 15. As a result, the developer and toner are not mixed sufficiently, and even if toner is replenished, the toner concentration on the sleeve of the developing roller 16 does not increase. That is, as shown by D in the graph of FIG. 13, the toner concentration G was lower than that calculated from the amount of toner replenishment, and the followability of the toner deteriorated. Furthermore, since the agglomerated toner cannot be triboelectrified until it is finely classified, the charging ability of the developer is low, and toner scattering and background smearing are more likely to occur.

On the other hand, in the device using the toner conveying brush 33, the supplied toner is finely classified and is further blown off and falls onto the stirring roller 34.
As shown by E in the graph of FIG. 13, the toner concentration is close to the calculated toner concentration G, and the toner followability is improved. Furthermore, since the supplied toner is finely classified without toner aggregation, the developer is sufficiently frictionally charged and has a charging ability, so that toner scattering and scumming do not occur.

[0031] Also, when comparing the two in terms of torque,
As shown in the graph of FIG. 14, the toner conveyance plate 30 has a strong stiffness, so the toner conveyance is 1.7 kgfcm, but the toner conveyance brush 33 is 1.0 kgfcm. Therefore, a small motor can be used to drive the agitator, which is effective in downsizing the device and saving labor.

In this embodiment, a developing device using a toner cartridge in the toner hopper section has been described, but the present invention can also be applied to a device that does not have a toner cartridge and has a toner hopper section built into the main body of the developing device.

[0033]

According to the above configuration, in the present invention, the agitator is divided into a toner conveying member that conveys toner and a toner agitating member that can engage with the conveying member and agitates toner.
The drive is transmitted to the toner agitating member, and since the toner conveying member and the agitating member are placed apart from each other in unused toner cartridges, even if there is toner aggregation, this can be broken up by the toner agitating member, and the toner aggregation is prevented. The torque when rotating the agitator can be significantly reduced.

Furthermore, in the present invention, the distance from the center of the agitator to the inner wall of the toner hopper section at areas other than the opening of the toner hopper section is set larger than the distance from the center of the agitator at the opening of the toner hopper section to the opening. Therefore, the agitator can be brought into sliding contact at the openings necessary for toner transport, and sliding contact can be eliminated or the sliding contact force can be reduced at areas other than the openings, and the torque during rotation of the agitator can be reduced.

Furthermore, in the present invention, even if the agitator is brought into sliding contact with the opening necessary for toner conveyance, the conveying member at the tip of the agitator is formed in a brush shape, so that the torque during rotation of the agitator is reduced and toner scattering is prevented. It also prevents dirt and stains.

[Brief explanation of drawings]

FIG. 1 is an overall schematic diagram showing an example of a laser printer using a developing device according to the present invention.

FIG. 2 is an enlarged view of the developing device.

FIG. 3 is an explanatory diagram showing a drive system of the developing device.

FIG. 4 is a perspective view of the toner transport plate of the agitator.

FIG. 5 is a perspective view of the toner stirring plate of the agitator.

FIG. 6 is a perspective view of the agitator in a state where the toner conveying plate and the toner stirring plate are in contact with each other.

7 is a sectional view showing the toner cartridge equipped with the agitator of FIG. 6 in an unused state; FIG.

FIG. 8 is a perspective view showing a modification of the toner stirring plate.

FIG. 9 is an explanatory cross-sectional view of a developing device showing another embodiment of the present invention.

10 is an explanatory cross-sectional view of a toner cartridge showing a modification of the embodiment shown in FIG. 9. FIG.

FIG. 11 is a perspective view showing an opening of the toner cartridge.

FIG. 12 is a cross-sectional explanatory view of a developing device showing still another embodiment of the present invention.

FIG. 13 is a graph showing toner densities of developing devices of the present invention and a conventional developing device.

FIG. 14 is a graph showing the magnitude of torque of developing devices of the present invention and a conventional developing device.

[Explanation of symbols]

4 Photoreceptor 7 Developing device 18 Toner cartridge 19 Opening 20 Cartridge body 21 Agitator 29 Toner stirring plate 30 Toner transport plate 32 Small hole 33 Toner transport brush

Claims (3)

[Claims] 1. A developing section having a developer carrier disposed opposite to the latent image carrier, a toner hopper section storing toner to be supplied to the developing section, and a toner hopper section formed in the toner hopper section, the developing section and an agitator for agitating the toner in the toner hopper section and supplying the toner to the developing section through the opening. The toner hopper section is configured as a toner cartridge, and an agitator of the toner cartridge is engageable with a toner conveying member that conveys toner, and a rotational driving force is transmitted to agitate the toner. A developing device characterized in that the toner stirring member is divided into two parts, and an unused toner cartridge is arranged with the toner conveying member and the toner stirring member separated. 2. A developing section having a developer carrier disposed opposite to the latent image carrier, a toner hopper section storing toner to be replenished to the developing section, and a toner hopper section formed in the toner hopper section, the developing section and an agitator for agitating the toner in the toner hopper section and supplying the toner to the developing section through the opening. An agitator is configured to be in sliding contact with the opening to replenish toner to the developing section, and with respect to a distance from the center of the agitator to the opening, the distance from the center of the agitator other than the opening to the toner hopper section is A developing device characterized in that the distance to the inner wall of the developing device is set to be large. 3. A developing section having a developer carrier arranged opposite to the latent image carrier, a toner hopper section storing toner to be supplied to the developing section, and a toner hopper section formed in the toner hopper section, the developing section and an agitator for agitating the toner in the toner hopper section and supplying the toner to the developing section through the opening. The opening is a plurality of small holes, and the agitator is configured to slide into the opening to replenish toner to the developing section,
A developing device characterized in that a conveying member at the tip of an agitator that slides into contact with the opening is formed in a brush shape.