JPS6221178A - Developing device - Google Patents

Abstract

PURPOSE:To uniformly supply a developer in the lengthwise direction of a nearly horizontal conveyance pipe in which toner flows by providing a screw which is positioned in the conveyance pipe and conveys toner and an opening part which two stages of slanting lower edges on the flank of the conveyance pipe. CONSTITUTION:When the toner in a developing device decreases in amount, the toner put in a hopper 36 is conveyed by the screw 35 to a hole part in order from below to fall in the conveyance pipe 33 positioned almost horizontally in a casing, and the screw 34 rotates counterclockwise to convey the toner. The opening part 41 has two stages of slanting lower edges which move down at the lower edge toward the front and is lowered at the front end part with large inclination. Consequently, toner is at almost the same height at any lower edge position of the opening part 41, so the toner is supplied uniformly in the lengthwise direction of the opening part.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a developing device, and more particularly to a developing device that can uniformly replenish the inside of the device while mixing toner in a hopper provided at the top with a developer. It is related to.

[Background of the invention]

Generally, development Aji used in image forming apparatuses, etc.
Since the amount of toner in the two-component developer decreases with use, a hopper is provided at the top of the developing device and the toner is stored inside the hopper to reduce the amount of toner in the developer. When the amount decreases, toner is supplied.

Then, the toner in the hopper and the developer whose toner content has been reduced are mixed and supplied again into the device. At the time of this mixing, the conveyor pipe, which has an internal screw, is operated by the screw. The developer and toner flow into the front side in the conveyance direction, are mixed and conveyed, and are sequentially dropped from an opening provided on the side of the conveyance pipe in the longitudinal direction of the conveyance pipe to ensure that there is enough toner in the device. The mixed developer is supplied.

However, since the filling rate of the developer inside the transport pipe gradually decreases along the length of the transport pipe from the front to the front in the transport direction, openings along the length are simply provided on the sides of the transport pipe. In this case, there is a problem in that it is only possible to drop the developer uniformly into the apparatus in the longitudinal direction of the conveying pipe, that is, to uniformly replenish the developer.

[Purpose of the invention]

This invention solves the above problems,
It is an object of the present invention to provide a developing device that can uniformly replenish developer along the longitudinal direction of a conveying pipe by focusing on the filling rate in the conveying pipe and the height of the developer in the conveying pipe during conveyance. do.

[Structure of the invention]

This invention provides a developing device configured to receive toner in a hopper provided at the top, transport it in a horizontal direction, and drop it into the inside of the device. a screw located in the conveying pipe to convey the toner along the conveying pipe; and a screw disposed on the side surface of the conveying pipe, the screw becoming downward in the forward direction in the conveying direction and having a tip portion that descends with a large slope. The structure includes an opening having a stepped lower edge.

[Embodiments of the invention]

Embodiments of the invention shown in the drawings will be described below.

FIG. 1 shows an electrophotographic copying apparatus which is a type of image forming apparatus equipped with a toner replenishing device according to the present invention, and a charging device 2 is provided above a photosensitive drum 1 which is an image carrier. An exposure section 3 is located ahead of the charging device 2 in the direction of rotation of the photosensitive drum 1, and a toner replenishing device 26 is located above the charging device 2.
A developing device 4 provided with a transfer pole 5, a separation pole 6, a cleaning device 7, and a post-exposure lamp 8 are each provided close to the photoreceptor drum 1.

Between the developing bag W4 and the transfer pole 5, two upper and lower paper feed trays (7) 9A and 9B are provided on the outside to make the paper thicker.
an upper and lower guide plate 10a for forming upper and lower paper feed paths;
10b and a middle plate 10c are provided, and a pair of upper and lower second feed rollers 11 are provided between the upper and lower guide plates 10a1tab.
a111b is located.

Further, paper feed rollers 12 are provided, which contact the top surface of the uppermost sheet of the sheets P in each of the paper feed cassettes 9 and feed the paper to the paper feed path.

Further, between the transfer pole 5 and the separation pole 6 and the fixing device 19, there is a conveyor belt 2 which is located downwardly as it goes forward.
A conveying device 22 is provided in which a roller 0 is stretched between rollers 21a and 21b, and a guide plate 23 is also provided so that the upper portion of the conveying heald 20 projects.

A toner collection box 24 for storing the collected toner collected by the cleaning device 7 is provided below the conveyance device 22, and this toner collection box 24 and
A communication member 25 is provided between the cleaning device 7 and the toner collected by the cleaning device 7 via the communication member 25 to the toner collection box 2.
It is designed to be guided within 4.

Further, FIG. 2 shows the developing device 4 and a toner replenishing device 26 provided above the developing device 4.
has a casing 27 that is open on the side of the photoreceptor drum L, and a stirring member 2 and a developing roller 29 are provided in the casing 27, and a developer on the surface of the developing roller 29 is disposed near the developing roller 29. regulating member 30 regulating the thickness of
A guide plate 31 is provided which is inclined inwardly from the regulating member 30, and near the lower end of this guide plate 31 is a conveyor pipe 3 in which an inlet port 32 is located.
3 is provided, and a screw 34 is located inside this conveying pipe 33.

Note that the inclination state of the guide plate 31 can be changed depending on the fluidity of the developer, that is, the toner concentration.

In addition, the upper part of the casing 27 has a screw 3 at the lower part.
5 is located, and a hole communicating with the hole provided in the conveying pipe 33 is provided on the lower surface of the hopper 36 on the forward side of the screw 35 in the conveying direction.

As shown in FIGS. 3 to 5, inside the hopper 36, a diaphragm 37 is provided on its inclined lower surface, and a portion 37a of the diaphragm 37 protrudes between the screw blades 38 of the screw 35. There is an L-shaped standing plate 3 on the top surface.
A plurality of spring plates 9 (three in the drawing) are provided, and a spring plate 40 is provided between an example of the diaphragm 37 and the inner surface of the hopper 36.
are connected.

On the other hand, the relationship between the conveyance pipe 33 and the toner replenishing device 26 is shown in FIG. A continuous opening 41 is provided which is successively wider in two stages.

A screw 34 is disposed inside the conveying pipe 33, and the forward side in the conveying direction is the wider direction of the opening 41 (FIG. 6).

Next, the action of 11; ■ will be explained.

First, 4; the photosensitive drum l charged by the staining device 2 is exposed to light to form an electrostatic latent image, and this electrostatic latent image is developed by the developing device 4 to become a toner image.

Further, the uppermost sheet of the sheets P stored in either one of the sheet feed cassettes 9 is sent out by the sheet feed roller 12, and the sheet feed is formed by the upper guide plate 10a and the inner inner board 10C. Road or middle interior board 10c and lower guide plate 10b
The second paper feed roller lla
, 11b, and is conveyed to a position facing the photoreceptor drum 1 at a predetermined timing, the toner image formed on the photoreceptor drum 1 is transferred to the paper by the transfer pole 5, and then the separation pole After being conveyed by the conveying belt 20 of the conveying device 22, which is separated by 6 and whose front end is inclined downward, the paper is fixed by the fixing device 19 by a guide member that directs the leading edge of the sheet upward. The paper is ejected outward by a paper ejection roller.

Further, after the toner image has been transferred to the paper, the photosensitive drum l rotates further and reaches the cleaning device 7, and then
The residual toner on the surface is removed by the blade 7a of the cleaning device 7, and after that, post-exposure is performed using a post-exposure lamp 8, thus completing one process and waiting for the next process.

The residual toner removed by the blade 7a of the cleaning device 7 is transferred to the toner collection box 24 disposed below the conveyance device 22 via a communication member 25 that communicates the cleaning device 7 and the toner collection box 24. It falls inside and is stored inside.

On the other hand, as the above-mentioned operations are repeated, the developer in the developing device 4, that is, the toner of the two-component developer, toner and carrier, decreases, so it is stored in the hopper 36. The toners are transported to the hole by the screw 35 in order from the bottom toner and fall into the transport pipe 33 located inside the casing 27.

The toner that has fallen into the conveying pipe 33 accumulates on the front side of the regulating member 30, is conveyed by the guide plate 31, and flows down into the conveying pipe 33 from the inlet port 32. It will be mixed with the agent.

In this way, the developer whose toner content has been reduced and the toner in the hopper 36 are mixed in the conveyance pipe 33 and conveyed forward by the screw 34, but the mixture in the conveyance pipe 33, that is, the developer is screw 3
It is conveyed at a certain angle by the rotation of step 4 (
(See Figure 7 01, θ2).

In this case, the state of the developer in the conveying pipe 33 is determined by the direction of rotation of the screw 34 as shown in FIG.
It becomes like bl.

That is, when the direction of rotation of the screw 34 is counterclockwise, it is as shown in FIG. 7 (al), and when it is clockwise, it is as shown in FIG. 7 (b).
Horizontal depending on the rotation direction of 4.

With respect to the direction, the front side in the rotation direction is high<(h), and the rear side in the rotation direction is low.

Since the developer is uniformly replenished while being transported in this state, that is, it is dropped into the casing 27 from the opening 41, the filling rate of the developer in the transport pipe 33 changes every moment in the longitudinal direction of the transport pipe 33. Along with this, the height h of the developer at the front in the rotational direction with respect to the horizontal line also changes.

FIG. 8 shows the relationship between the filling rate and the height when the screw 34 is rotated clockwise and counterclockwise. In this figure, ○ indicates a toner concentration of 5%, and . 5% and Δ indicate that the toner concentration is 10%, ◯ and Δ indicate that the screw 34 rotates counterclockwise, and * indicates that the screw 34 rotates clockwise.

As is clear from this figure, the difference in height due to the filling rate is smaller in the counterclockwise direction, so when downsizing the developing device, the conveying pipe and screw should be made smaller, and the filling rate should be increased. Therefore, replenishing by rotating the screw counterclockwise is more advantageous for uniform replenishment.

Note that since the developer is dropped from the opening 41 of the conveying pipe 33 by rotating the screw 34 clockwise or counterclockwise, the height of the lower edge of the opening '41 of the conveying pipe 33 is the same as shown in FIG. In the illustrated embodiment, the screw 34 rotates counterclockwise to convey the developer, and the opening becomes downward as its lower edge goes forward. At the same time, it has a two-step sloped lower edge where the tip descends at a large slope.

By forming the lower edge of the opening in this way, the developer is at almost the same height no matter where the lower edge of the opening is located, making it possible to replenish uniformly across the length of the opening. It is something.

As described above, the developer is uniformly dropped into the upper interior of the casing 27 of the developing bag W4, and the developer is sequentially dropped into the hopper 3.
The toner inside the hopper falls into the conveying pipe 33, but since the toner has low fluidity, only the toner on the inside is conveyed on the slanted lower surface of the hopper, and the toner on the outside retains its shape, so-called. Although blurring may occur, the diaphragm 3 which has an upright plate 39 on the upper surface of the inclined lower surface of the hopper 36
7 is located, and this diaphragm 37 is connected with the inner surface of the hopper 36 by a spring 40, and a part of the diaphragm 37 is located within the screw blade 38 of the screw 35, so that the screw 35 When the diaphragm 37 is rotated, the diaphragm 37 is tilted in the conveying direction, and when the screw blade 38 overcomes the diaphragm 37, it returns to its original state due to the biasing force of the spring plate 40, and thus vibrates to prevent the toner from becoming blurred. This can be prevented.

Therefore, the slope of the lower surface of the hopper may be small, and even if the height of the hopper is lowered, the hopper can be made smaller and accommodate a larger amount of toner.

〔Effect of the invention〕

With the above-described structure, the present invention allows the toner and the developer with reduced toner to be mixed and sequentially dropped while being conveyed in the longitudinal direction of the conveying pipe, thereby uniformly developing the toner along the longitudinal direction of the conveying pipe. It has excellent effects such as being able to replenish drugs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an image forming apparatus equipped with an image forming apparatus according to the present invention, FIG. 2 is a schematic diagram showing a developing device and a toner replenishing device provided above it, and FIG. 3 is a diagram showing a diaphragm. , FIG. 4 is a schematic diagram of the toner replenishing device, and FIG. 5 is a schematic perspective view showing the relationship between the toner replenishing device and the conveying pipe.
Figure 6 is a diagram showing the relationship between the conveyance pipe and the screw, Figure 7 + al (bl is a diagram showing the relationship between the screw rotation direction and the toner height, and Figure 8 is the relationship between the toner height and the filling rate. FIG. Separation electrode 7... Cleaning devices 9A, 9B... Paper feed cassette 22... Conveying device 26... Toner replenishing device 31... Guide Plate 32... Inflow port 33... Conveying pipe 34.35... Screw 36... Hopper 37... Vibration plate 38... ...Screw blade 39...Upper plate 40...Spring plate 41...Opening part Fig. 3

Claims (1)

[Claims] In a developing device that receives toner in a hopper provided at the top and transports it in a horizontal direction, it falls into the inside of the device. a screw positioned to transport the toner along the transport pipe;
On the side surface of the conveying pipe, there is a groove 2 which becomes downward in the forward direction in the conveying direction and whose tip part descends with a large slope.
A developing device comprising an opening having a stepped lower edge.