JP2527797Y2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a developing device used for an image forming apparatus such as a printer and a facsimile machine, and more specifically, a filter member for adsorbing and removing scattered toner. The present invention relates to improvement of a developing device provided.

(Prior Art) Copiers, printers, facsimile machines and the like as image forming apparatuses utilizing an electrophotographic process are obtained by irradiating uniformly charged photoconductors with optical image information such as original reflected light. After the electrostatic latent image is visualized by toner applied from a developing device, the visible image is transferred to a recording sheet and fixed to form an image.

As is well known, a conventional developing device is disposed in the vicinity of a photosensitive drum constituting an image forming unit, and visualizes an electrostatic latent image by attaching toner as a developer to the photosensitive drum. Recent developing devices include an air purifying chamber provided with a filter member for adsorbing and removing toner scattered from a gap between the photosensitive drum and the air from the air and provided at an upper portion of a casing, and an air purifying chamber. And a pair of left and right ducts that forcibly guide air under the casing to an air purifying chamber by driving a fan provided in the air conditioner.

Such an air purifying chamber is generally provided on the side of a toner tank containing toner in order to reduce the size of the entire developing device. Therefore, as shown in FIGS. 5 and 6, the duct 101 which connects the air purifying chamber located at the upper part of the casing and the lower part of the casing has a U-shape having two substantially bent portions at right angles. doing.

However, in such a conventional developing device, the large-diameter toner T having a large mass out of the scattered toner guided into the duct 101 is caused by the inertia force of the toner itself.
After colliding with the wall surface of the duct 1, it falls by its own weight and accumulates in the bent portion 101a located at the lower part of the duct 101, so that it easily adheres. For this reason, the area of the hollow portion of the duct 101 decreases over time, and the flow passage of the air containing the scattered toner is blocked, thereby deteriorating the toner removal efficiency.
It was necessary to increase the frequency of maintenance.

In addition, since maintenance of the duct 101 is generally performed by loosening a fixing screw (not shown) to remove the duct 101 itself from the developing device, there is a problem that the operation itself is troublesome.

Further, it is not easy to determine the maintenance time, and the maintenance may not be performed even if the duct 101 is closed, or a complicated removal operation may be performed even if the toner accumulation is small.

(Purpose of the Invention) The present invention has been made in view of the above problems, and aims to provide a phenomenon device that can reduce the frequency of maintenance of a duct, is easy to perform the work, and easily determines a maintenance time. .

(Structure of the Invention) In order to achieve the above object, the present invention provides a developing sleeve provided in an image forming apparatus for attaching a developer to an electrostatic latent image on a photoreceptor to visualize the electrostatic latent image, and a scattered toner. In a developing device having a duct for guiding air around the developing sleeve to the filter member for suction, a toner reservoir portion for suppressing scattered toner in the duct from closing the duct is formed to protrude below the duct. It is characterized by having.

Further, the toner reservoir is formed separately from the duct so that the toner accumulated in the toner reservoir is discarded or the toner reservoir is replaced, and the toner reservoir is detachable from the duct.

Further, at least the toner reservoir is made of a transparent material so that the toner accumulated in the toner reservoir can be visually recognized.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1 and 2 are a perspective view and a sectional view, respectively, of a developing device according to an embodiment of the present invention applied to a copying machine. First, the configuration of a general developing device will be described with reference to FIG. 2. The developing device 1 includes a developing device 1 in a casing 5 fixed by fixing screws (not shown) between opposed side plates 3, 3. And a developing device main body 11 for attaching toner to an electrostatic latent image formed on the surface of the photosensitive drum 9 and visualizing the toner. And the device body 11 are open
The toner is replenished from the toner tank 7 to the apparatus main body 11 by rotating a replenishing roller 15 provided at the opening 13 and communicated through the opening 13. The toner is replenished by the replenishing roller 15 when, for example, the toner concentration of an agent composed of a mixture of toner and a carrier (small iron ball) decreases, the toner concentration of the agent itself is detected, or This is done by detecting the attached toner concentration and driving an electromagnetic clutch (not shown) when the detected value exceeds a predetermined value.

In the apparatus main body 11, a developing sleeve 21 having a fixed magnet 17 and a thin cylindrical tube 19 rotatably arranged outside the fixed magnet 17 and facing the photosensitive drum 9 with a predetermined gap is provided. And a paddle wheel 23 for pumping the agent toward the developing sleeve 21, a doctor blade 25 for regulating the thickness of the agent on the developing sleeve 21 to be uniform, and a doctor blade
A guide plate 27 serving as a transport route of the agent regulated by 25,
A small paddle 29 is provided below the guide plate 27 to prevent the accumulation of the agent pool. The upper part of the apparatus main body 11 having such a configuration is covered by an upper cover 31.

The guide plate 27 is formed integrally with a horizontal portion 33 and an inclined portion 35. The transport screw 37 is located below the horizontal section 33.
As shown in FIG. 3, the transport screw 37 transports the agent dropped from the hole 39 formed in the horizontal portion 33 rightward in FIG. 2 (from the near side to the far side in FIG. 2). It is configured to fall from the hole 40. Conversely, a plurality of guide fins for guiding the agent on the back side to the front side in FIG.
41,41 are erected. As a result, the agent in the apparatus main body 11 is sufficiently stirred and transported.

A rotatable agitator 43 is provided in the toner tank 7.
The agitator 43 stirs the toner in the toner tank 7 to prevent the toner from being shifted.

The replenishing roller 15, the developing sleeve 21, the paddle wheel 23, the small paddle 29, the transport screw 37, the agitator 43
Is rotated by transmitting torque from a drive source (not shown).

The upper cover 31 and the upper defining plate 4
5. Two air purifying chambers 51, 51 defined between the side plate 47 and the front and rear partition walls 49 are provided. Upper and lower partitions 53 are fixed between the upper cover 31 and the upper defining plate 45, and the upper and lower partitions 53 are fixed.
Holes 55, 55 are formed on the front and rear partition walls 49, and holes 57, 57 are formed on both ends of the upper defining plate 45, so that the duct portion shown by an arrow in FIG. 59 are formed. At the top of the upper cover 31, a duct 59
Fan that generates airflow in the direction of the arrow
61, 61 are connecting members 62, 62 and L-shaped cross-section brackets 63, 6
Fixed through three.

Each fan 61, 61 is provided with filter members 65, 65 for adsorbing scattered toner on the surface and purifying the air,
When the fans 61, 61 are driven, the air introduced into the duct portion 59 is cleaned by passing through the filter members 65, 65. The filter members 65, 65 are detachable from the fans 61, 61. That is, cylindrical portions 67, 67 are erected on the side plates 47, 47 side of the fans 61, 61, and the filter members 65, 6 are attached to the cylindrical portions 67, 67.
One end of 5 is inserted, and the other ends of the filter members 65, 65 are pressed and supported in the insertion direction (axial direction) by leaf springs 69, 69 fixed on the upper cover 31 by welding or the like. . Therefore, each of the filter members 65, 65 is brought into the cylindrical portions 67, 6 of the fans 61, 61 by tilting the leaf springs 69, 69 left and right.
Can be extracted from 7.

On the other hand, a lower defining plate 71 extending in the axial direction of the developing sleeve 21 is fixed to a lower portion of the casing 5 in which the photosensitive drum 9 and the developing sleeve 21 are opposed to each other. A negative pressure chamber 73 is formed between the photosensitive drum 9 and the photosensitive drum 9.

External duct members 75, 75 for transporting the scattered toner in the negative pressure chamber 73 together with the surrounding air to the filter members 65, 65 are fixed to the sides of the side plates 3, 3 with fixing screws 76 and the like. Each duct member 75 has a vertically long U-shaped cross-section so as to communicate an opening 77 formed at both ends in the front-rear direction of the negative pressure chamber 73 and an opening 79 formed in the side wall 47 of the air purification chamber 51. In addition, a toner reservoir 81 for suppressing the scattering toner in the duct member 75 from closing the duct member 75 is formed to protrude below the duct member 75.

Around the photosensitive drum 9, a charger for charging the surface of the photosensitive drum 9 to a predetermined potential (about 850 V) in the rotation direction indicated by an arrow, and an original image is exposed on the charged photosensitive drum 9. An optical system for forming an electrostatic latent image by developing the toner, a developing device 1 according to the present invention for attaching toner to the electrostatic latent image on the photosensitive drum 9 and visualizing the toner, and a photosensitive drum 9 after development. Although not shown, a transfer charger for transferring the upper toner image onto transfer paper is provided. The copying apparatus further includes a fixing device that heats and compresses the toner image on the transfer paper and fuses the toner image onto the transfer paper, so that the transfer paper after fixing is discharged.

Here, when the photosensitive drum 9 is exposed by the optical system, the surface potential of the image portion remains around 850 V, whereas the surface potential of the background portion other than the image portion decreases to about 0 to 50 V. The developing sleeve 21 is charged with a voltage of about 400 V in advance, so that the toner on the developing sleeve 21 adheres to the image area (surface potential is around 850 V), so that development is performed.

 Next, the operation will be described.

The agent on the developing sleeve 21 is regulated to a uniform thickness by the doctor blade 25, and the fixed magnet 17 inside the developing sleeve 21 is fixed.
The toner comes into contact with the surface of the photosensitive drum 9 in a state where the agent rises along the lines of magnetic force formed by the toner particles, and the toner adhered to the carrier by frictional charge adheres to the image portion of the photosensitive drum 9. The toner whose toner concentration has decreased due to the toner adhering to the photosensitive drum 9 falls by its own weight at a place where the magnetic force does not reach (a place where the magnets are separated) and moves to the paddle wheel 23. Since the paddle wheel 23 rotates clockwise in FIG. 2 to mechanically pump the agent, the pumped agent and the agent regulated by the doctor blade 25 are guided by the guide plate 27 and run down. Mix together. Further, when the agent flowing down from the guide plate 27 is pumped up by the paddle wheel 23, it is again carried on the developing sleeve 21 by the magnetic force of the fixed magnet 17.

The agent flowing down on the guide plate 27 is sequentially brought from the back side to the front side by the inclined guide fins 41, 41,
The foremost agent is sent to the back side by the transport screw.

When the fan 61 is driven to rotate, the duct member 75
, A negative pressure is introduced into a negative pressure chamber 73 formed between the casing 5 and the lower defining plate 71. When the toner scatters from the opening of the casing 5 where the developing sleeve 21 is opposed to the photosensitive drum 9, the scattered toner is transferred to the negative pressure chamber 73 and the duct member.
By passing through the filter member 65 via 75, it is adsorbed on the filter member 65. The clean air after the scattered toner is adsorbed is discharged to the outside from the hole 57 through the duct portion 59 by the fan 61.

When the scattered toner is sucked into the duct member 75, the large-diameter toner having a large mass collides with the inner wall of the duct member 75 and then falls by its own weight, as described in the conventional example. The large-diameter toner that has dropped due to its own weight accumulates in the toner reservoir 81 protruding from the lower portion of the duct member 75. Therefore, it is possible to prevent the efficiency of removing the scattered toner from decreasing. Therefore, the duct member
The effect of greatly reducing the maintenance frequency of 75 can be obtained.

FIG. 4 shows another embodiment. In this embodiment, the toner reservoir 81 is configured to be detachable from the duct member 75. That is, the toner reservoir 81 has a box shape, and an upper side portion 81 a thereof is fitted to a fitting portion 75 a formed below the duct member 75. According to this embodiment, during maintenance of the duct member 75, only the toner reservoir 81 is removed, and the toner accumulated inside is discarded or replaced, thereby removing the duct member 75 itself by loosening the fixing screw 76. The work becomes remarkably easy as compared with the one. In addition, it is difficult to confirm whether the toner has been completely discarded with the integrated duct member, but the effect is that the confirmation is easy.

Further, if the toner reservoir 81 is made of a transparent material, the state of toner accumulation can be visually checked, and the maintenance time of the duct member 75 can be easily determined. As a result, maintenance is not performed even when the duct is closed. On the contrary, there is no need to perform a complicated removal operation even if the toner accumulation is slight. In this case, the toner reservoir 81 need not be configured to be detachable from the duct member 75,
Not only the toner reservoir 81 but also the lower part of the duct member 75 and the entire duct member 75 may be made of a transparent material.

(Effects of the Invention) As described above, according to the invention, the toner reservoir for preventing the scattered toner from blocking the duct is formed to protrude from the lower part of the duct, so that the duct remains until the toner reservoir becomes full. Maintenance can be postponed and maintenance costs can be reduced.

In addition, since the toner reservoir is configured to be removable from the duct in order to discard the toner accumulated in the toner reservoir or to replace the toner reservoir, the operation is facilitated, and the toner is easily removed. It is also easy to confirm whether or not it has been completely discarded.

Further, since the toner reservoir is made of a transparent material so that the toner accumulated in the toner reservoir can be visually recognized, the maintenance time can be easily determined.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of the developing device according to the present invention, FIG. 2 is a sectional view taken along line II of FIG. 1, FIG. 3 is a perspective view of a main part of another embodiment, and FIG. FIG. 5 is a sectional view of a duct provided in the developing device, FIG. 5 is a perspective view of a conventional duct, and FIG. 6 is a sectional view taken along the line II-II of FIG. 9 photoconductor drum, 21 developing sleeve, 61 fan, 65 filter member, 75 duct member, 81 toner reservoir, T toner (developer)

Claims (3)

(57) [Scope of request for utility model registration] A developing sleeve provided on an image forming apparatus utilizing an electrophotographic process for adhering a developer to an electrostatic latent image on a photosensitive member to visualize the electrostatic latent image; and a developing sleeve for adhering scattered toner. A developing device having a duct for guiding air around the sleeve to the filter member, wherein a toner reservoir for preventing scattered toner in the duct from closing the duct is formed to protrude below the duct. Characteristic developing device. 2. The developing device according to claim 1, wherein the toner reservoir is formed separately from the duct for discarding the toner accumulated in the toner reservoir or replacing the toner reservoir. A developing device which is detachable from the developing device. 3. The developing device according to claim 1, wherein at least the toner reservoir is made of a transparent material so that the toner accumulated in the toner reservoir can be visually recognized. Developing device.