JPH03174175A - Developing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a developing device that is used in an electrophotographic recording device such as a laser beam printer and executes a developing process during an electrophotographic process. .

(Prior Art) As one of the developing methods in the development process of the electrophotographic recording method, magnetic carrier is stored around a developer carrier roll in a storage container that stores magnetic toner and magnetic carrier, and this development method is used. There is a method of mixing magnetic toner and magnetic carrier near the agent carrier roll.

FIG. 6 is a sectional view showing an example of the configuration of a conventional developing device that performs development using such a developing method. In the figure, reference numeral 1 denotes a developer carrier roll, which is provided in parallel to a photoreceptor drum (not shown).

This developer carrier roll 1 consists of a cylindrical sleeve 1a made of a non-magnetic material and a magnet roll 1b provided inside the sleeve 1a. Each rotates in the direction of B. and developer carrier roll 1
is located at the opening of the hopper 2 with a portion thereof located within the storage container (hereinafter referred to as hopper) 2.

Hopper 2 contains magnetic toner (hereinafter referred to as toner).
3 and a magnetic carrier (hereinafter referred to as carrier) 4 are stored. A blade 5 is provided at the toner outlet 2a of the hopper 2, and when the developer carrier roll 1 is rotated, the toner 3 and carrier carried on the developer carrier roll 1 are guided to the outside of the hopper 2. This is to keep the amount of 4 constant. Note that 6 is an agitator that supplies the toner 3 to the vicinity of the developer carrier roll 1 and stirs the toner 3, and rotates in the direction of arrow C.

In such a developing device, in the initial state, the carrier 4 is attached to the developer carrier roll 1 as shown by the broken line in the figure.
is located near. In addition, the developer carrier roll 1
It is also attached to the surrounding area.

Then, the toner 3 is mixed little by little into the carrier 4 and carried on the developer carrying roll 1.

However, with such a configuration, the rotation of the sleeve 1a causes the carrier 4 to move in the direction shown by the arrow in FIG. The mixing ratio (toner concentration) of toner 3 and carrier 4 will change.

By the way, FIG. 7 shows the relationship between the toner concentration on the developer carrier roll 1 and the time during which the toner 3 carried and conveyed by the developer carrier roll 1 is in contact with the photoreceptor drum (development time). The diagram shown in FIG. 8 is a diagram showing the relationship between toner density and image density.

As can be seen from FIGS. 7 and 8, the toner concentration on the developer carrier roll 1 has a great relationship with recording characteristics. Therefore, if the toner density changes as described above, variations will occur in the recorded image.

Further, the carrier 4 also has a cleaning function on the sleeve 1a, but by dispersing the carrier 4, the sleeve 1a is cleaned.
There is a risk that the cleaning action on the sleeve 1a will be insufficient, and blocking toner will be formed on the sleeve 1a, resulting in a deterioration in the quality of the recorded image.

(Problems to be Solved by the Invention) As described above, in the conventional developing device, the carrier is simply disposed near the developer carrier roll, so the carrier is dispersed by rotation of the developer carrier roll 1, etc. This causes problems in that the toner density changes and blocking toner is left on the developer carrier roll, causing density variations and deterioration of image quality in recorded images.

The present invention has been made in consideration of these circumstances, and its purpose is to maintain constant toner concentration and carrier amount on the developer carrier roll and to stably record high-quality images. An object of the present invention is to provide a developing device that can perform the following steps.

[Structure of the Invention] (Means for Solving the Problems) The present invention temporarily stores magnetic toner supplied from a storage container. For example, the supply of magnetic toner from the storage container is caused by the weight of the magnetic toner. The temporary developer storage section has a shape in which the magnetic toner is formed, and the bottom part is an inclined surface at an angle at which the magnetic toner falls under its own weight. A mixing section that mixes the magnetic carrier that has been loaded in advance and the magnetic carrier that has been stored in advance, and a magnetic carrier and magnetic toner that are connected to this mixing section and mixed in the mixing section. and a conveyance path through which the developer carrier is conveyed by the developer carrier roll.

Further, an elastic member having a length that contacts the bottom of the storage container is provided on a toner supply means for supplying the magnetic toner stored in the storage container to the vicinity of the developer carrier roll or to the temporary developer storage section. .

(Function) According to the present invention, the magnetic toner supplied from the storage container has a shape in which, for example, the supply of the magnetic toner from the storage container is performed by the magnetic toner's own weight, and the magnetic toner falls from the bottom part by its own weight. The developer is temporarily stored in a temporary developer storage section having an inclined surface at an angle of . The magnetic toner stored in this developer temporary storage section is, for example, once loaded onto a provided platform, and then taken into a mixing section where it is mixed with the magnetic carrier stored in advance. The developer is conveyed by the developer carrier roll through a conveyance path connected to the mixing section. Therefore, the magnetic carrier is almost isolated from the storage container, and the magnetic carrier is held near the developer carrier roll without diffusing into the storage container, and the magnetic toner is kept near the developer carrier roll. is stably supplied.

Furthermore, the magnetic toner is more stably supplied to the vicinity of the developer carrier roll or to the developer temporary storage section by an elastic member provided in the toner supply means and having a length that comes into contact with the bottom of the storage container. Ru.

(Example) Hereinafter, a first example of the developing device of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a schematic configuration of the developing device. Note that the same parts as in FIG. 6 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In the figure, 10 is a hopper as a storage container.

This hopper 10 has a protruding part 10a whose bottom surface substantially follows the circumferential surface of the sleeve 1a, formed on the wall part of the upper side of the sleeve 1a. Also hopper 1
The bottom surface of the sleeve 1 is composed of a first portion 10b having an arcuate cross section and a second portion 10c protruding from the first portion so as to cover the lower part of the sleeve 1a. As shown in the figure, the connecting portion is shaped like a square. Further, the inclination of the second portion 10c located on the side of the sleeve 1a is set at an angle greater than or equal to the angle at which the toner 3 easily falls due to its own weight (the angle of repose of the toner 3), and the upper surface is shaped to be flat. A protrusion 10d is formed.

Here, the bottom surface of the protrusion 10a has a predetermined distance from the sleeve 1a, forming a space 11. In addition, space 1
1, when the cross-sectional area S is the radius of the sleeve 1a, 1, Or≦S≦10. It is desirable that it be within the range of Or.

Also, the tip of the protrusion 10a (8 points in the figure) is located at the hopper 1.
0 and has a predetermined distance from the bottom surface. Furthermore, the protrusion 10
The tip of a (point 8 in the figure) is the top of the joint between the first part 10b and the second part 10c of the hopper 10 (point P in the figure).
point).

Next, the operation of the present developing device configured as described above will be explained.

FIG. 2 is an enlarged view showing the vicinity of the developer carrier roll 1 in FIG. 1.

First, in the initial state, a predetermined amount of carrier 4 and a predetermined amount of toner 3 are mixed and fully stored in the space 11 so that the toner concentration becomes a predetermined value (hereinafter, the toner stored in this space 11 3 and carrier 4 is called a mixed layer). Here, in order to record a clear image, it is desirable to optimally set the volume of the space 11 and the amount of carrier 4, and to set the toner concentration to about 20 to 90% (more preferably 40 to 70%). . Further, the hopper 10 stores toner 3 for replenishment.

At this time, since the space 11 is full, the hopper 1
The toner 3 supplied from 0 to the space 11 cannot enter the space 11, and is stored in the space formed between the protrusion 10a and the second portion 10c at the bottom of the hopper 10 (hereinafter referred to as sub-hopper). 12 is temporarily stored. In other words, this sub-hopper 12 functions as a temporary developer storage section. Here, in this sub-hopper 12, the part of the second part 10c located on the side of the sleeve 1a becomes the bottom part, but the part of the second part 10c located on the side of the sleeve 1a has an inclination. is set to be greater than the angle of repose of the toner 3, so the bottom of the sub-hopper 12 is an inclined surface having an angle greater than the angle of repose of the toner 3.

Here, when the developing operation is performed and the toner 3 in the space 11 is consumed, a margin is created in the space 11.

Then, the toner 3 stored in the sub-hopper 12 falls onto the upper surface of the protrusion 10d, is taken into the space 11 by the rotation of the sleeve 1a, the magnetic force of the magnet roll 1b, and is mixed with the carrier 4. At this time, the newly supplied toner 3 and carrier 4 are mixed as follows.
This is mainly the space shown by the dashed line 11a in the figure (hereinafter referred to as the mixing section space), and the mixing section space 11a is the space where the toner 3
At the stage where the carrier 4 is transported, the toner 3
and carrier 4 are mixed. That is, this mixing section space 11a functions as a mixing section.

The mixed layer thus obtained in the mixing section 11a is in the space 11.
is transported through the remaining space (hereinafter referred to as transport path space) 11b, and guided to the outside through the m1 gap between the sleeve 1a and the blade 5. In other words, the conveyance path space 11b functions as a conveyance path.

Note that the toner 3 and carrier 4 are transported in this conveyance path space 11.
Also at the stage when the toner is being conveyed, one stirring is performed by the movement, and the toner concentration is brought closer to the optimum value.

As described above, in this embodiment, the supply of toner 3 from the hopper 10 to the developer carrier roll 1 is controlled by the sub-hopper 12.
Instead of pushing out the toner 3 from the hopper 10 side toward the developer carrier roll 1,
Since the developer carrier roll 1 has a structure in which the toner 3 is taken in by the magnetic force of the magnet roll, the toner 3 is always stably supplied to the developer carrier roll 1.

Further, the mixing of the toner 3 and the carrier 4 and the conveyance of the mixed layer are carried out between the mixing section chamber 11a and the conveyance path space 11b, which are separated from the space in which the toner 3 for replenishment of the hopper 10 is stored.
Since the configuration is such that the carriers 4 do not move from the mixing chamber 11a and the conveyance path space 11b to other spaces in the hopper 10, the carriers 4 do not become dispersed.

Furthermore, in this embodiment, the tip of the protrusion 10a (8 in the figure)
point) is the first part 10b and the second part 10 of the hopper 10.
It is set at a lower position than the top of the joint part with c (point P in the figure). Also, the second portion 10c of the hopper 10
The inclination angle of the bottom portion of the sub-hopper 12 is set to be greater than the angle of repose of the toner 3. Therefore, the toner 3 is not forced into the sub-hopper 12 by the agitator 6, and the toner is supplied to the sub-hopper 12 only by the weight of the toner 3. Thereby, the toner 3 can be supplied to the space 11 more stably.

Further, by providing a protrusion 10d and mixing the toner 3 placed on the upper surface of the protrusion 10d with the carrier 4, the toner 3 is taken into the space 11 by the rotation of the sleeve 1a and the magnetic force of the magnet roll 1b. can be done with certainty. Note that this protrusion 10d is
It also has the effect of preventing the mixed layer from flowing back.

Due to these various actions, the toner 3 in the space 11
and the amount of carrier 4 can be constant,
The toner concentration on the developing sleeve la can always be kept constant. Therefore, the image density becomes stable, and since recording can always be performed under optimal conditions, clear images can be obtained. Note that the diameter of sleeve 1 is 18 m.
m, in a developing device with a developing width of 2601111,
When an experiment was conducted using 10 g of carrier 4, the toner concentration was maintained constant at about 65%.

By the way, the agitator 6 generally has a configuration as shown in FIG. In the figure, 6a and 6b are toner conveying members each having a shape in which both ends of a rod are bent vertically in the same direction, and are disposed opposite to each other with a cylindrical shaft 6C in between. Thus, by rotating this agitator 6 in the direction of arrow C in one hopper 10 as shown in FIG.
The toner 3 is supplied to the toner 2.

However, in the agitator 6 having the configuration shown in the third figure, when the amount of toner 3 stored in the hopper 10 decreases, the toner conveying ability of the toner conveying members 6a and 6b decreases, and the toner 3 is not supplied properly. There are cases where this happens. This is because the protrusion 10a is provided as in the present application,
This becomes a problem especially when the opening for supplying toner to the vicinity of the developer carrier roll 1 is small.

Hereinafter, a second embodiment of the present application will be described in which measures are taken to prevent such problems from occurring.

FIG. 4 is a sectional view showing a schematic structure of the present developing device, and FIG. 5 is a perspective view showing the structure of an agitator.

As shown in FIGS. 4 and 5, a hopper 1 is connected to an agitator 6 similar to that shown in FIGS. 1 and 3.
Elastic members 21 and 22 are added with a length that contacts the first portion 10b (bottom surface of the hopper 10) of the hopper 10. This elastic member 2
1.22 is formed by impregnating nylon with rubber, for example.

Thus, by configuring the agitator 6 as described above, the toner 3 located at the bottom of the hopper 10 is scraped out toward the sub-hopper 12 by the elastic members 21 and 22, and the amount of toner remaining in the hopper 10 decreases. The toner 3 can be properly supplied to the sub-hopper 12 even when the toner 3 is in use.

Therefore, the toner 3 is stably supplied from the sub-hopper 12 to the mixing section space 11a, and fluctuations in toner concentration can be prevented.

Further, as shown in FIG. 4, the length from the axis of the shaft 6C of the agitator 6 to the tips of the elastic members 21 and 22 is made larger than the length from the axis of the shaft 6C to the first portion 10b of the hopper 10. As a result, the tips of the elastic members 21 and 22 protrude and pass through the upper part of the sub-hopper 12, and the toner 3 located at the upper part of the sub-hopper 12 is agitated. This prevents toner from agglomerating in this area. At this time, the elastic member 2
The difference (protrusion fi) between the length between the tips of 1.22 and the length from the axis of 1116C to the first portion 10b of the hopper 10 is, for example, 3, The optimum value changes depending on the shape and dimensions of the agitator 6, the rotation speed of the agitator 6, etc.

Note that the present invention is not limited to the above embodiments.

For example, in the above embodiment, the tip of the protrusion 10a (8 points in the figure) is connected to the first part 10b and the second part 1 of the hopper 10.
By setting the position lower than the top of the joining part with 0c (point P in the figure), the toner 3 is
However, if the agitator 6 is not provided, for example, the above-mentioned configuration is not necessary. In addition, the bottom of the sub-hopper 12 is
Although it is desirable that the slope has an angle of repose greater than or equal to the angle of repose of the toner 3, it does not necessarily have to be an inclined surface that has an angle of repose greater than or equal to the angle of repose of the toner 3. For example, it may be a horizontal surface or an inclined surface that has an angle of repose less than or equal to the angle of repose of the toner 3, or An inclined surface having an angle of repose greater than or equal to the angle of repose of the toner 3, an inclined surface less than the angle of repose of the toner 3, a horizontal surface, etc. may be mixed.

Further, in the second embodiment, elastic members 21 and 22 are added to the agitator 6 of the developing device of the first embodiment, but for example, elastic members 21 and 22 are added to the agitator of the conventional developing device shown in FIG. 21.22 may also be applied. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the present invention, the magnetic toner supplied from the storage container is temporarily stored, for example, the magnetic toner is supplied from the storage container by the weight of the magnetic toner, and There is a temporary developer storage section whose bottom part is an inclined surface at an angle where the magnetic toner falls under its own weight, and the magnetic toner stored in this temporary developer storage section is taken in after being once loaded onto a provided platform, for example. The magnetic carrier and magnetic toner mixed in the mixing section are connected to a mixing section that mixes the taken-in magnetic toner and pre-stored magnetic carrier, and the developer carrier roll is connected to the mixing section. Since the developer is provided with a conveyance path during conveyance, it is possible to keep the toner concentration and carrier amount on the developer carrier roll constant, and to stably record high-quality images.

Further, an elastic member having a length that contacts the bottom of the storage container is provided on a toner supply means for supplying the magnetic toner stored in the storage container to the vicinity of the developer carrier roll or to the temporary developer storage section. Therefore, this elastic member allows more stable supply of magnetic toner to the vicinity of the developer carrier roll or to the developer temporary storage section.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining a developing device according to a first embodiment of the present invention, in which FIG. 1 is a cross-sectional view showing a schematic configuration, and FIG. 2 is a diagram showing a developer carrier in FIG. FIGS. 3 to 5 are diagrams showing an enlarged view of the periphery of the body roll 1, and FIGS. 3 to 5 are diagrams for explaining a developing device according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view showing the schematic structure of the developing device of this embodiment, FIG. 5 is a perspective view showing the structure of the agitator of this embodiment, and FIGS. 6 to 8 respectively show the prior art. FIG. 1...Developer carrier roll, 1a...Sleeve, 1
b... Magnet, 3... Toner 4... Carrier,
5...Blade, 6...Agitator, 6a, 6b・
...Toner conveying member, 6c...Shaft, 10...Hopper 10a, 10d...Protrusion part, 11...Space, ll
a... Mixing section space, 11b... Conveying path space, 12.
...Sub hopper 21.22...Elastic member.

Claims (6)

[Claims] (1) A storage container that stores magnetic toner and magnetic carrier; and a developer carrier roll that supports the magnetic toner stored in the storage container by magnetic force and rotates to convey the magnetic toner and magnetic carrier. The developing device includes a developer temporary storage section for temporarily storing magnetic toner supplied from the storage container, and a developer temporary storage section that takes in the magnetic toner stored in the developer temporary storage section. a mixing section for mixing the mixed magnetic toner and pre-stored magnetic carrier; and a mixing section that is connected to the mixing section, and the magnetic carrier and magnetic toner mixed in the mixing section are transported by the developer carrier roll. What is claimed is: 1. A developing device characterized by comprising a conveyance path for carrying out the development. (2) The developing device according to claim 1, wherein the temporary developer storage section has a shape in which the magnetic toner is supplied from the storage container by the magnetic toner's own weight. (3) The developing device according to claim 1, wherein the bottom of the temporary developer storage section is an inclined surface at an angle at which the magnetic toner falls under its own weight. (4) The developing device according to claim 1, wherein the mixing section has a platform and mixes the magnetic toner and magnetic carrier placed on the platform. (5) A toner supply means that rotates within the storage container and supplies the magnetic toner stored in the storage container to a temporary developer storage section, and the toner supply means includes a bottom portion of the storage container. The developing device according to claim 1, further comprising an elastic member having a length that comes into contact with the developing device. (6) a storage container for storing magnetic toner and magnetic carrier; a part of the storage container is provided inside the storage container, and the magnetic toner and magnetic carrier stored in the storage container are supported by magnetic force; a developer carrier roll that rotates to convey the magnetic toner and magnetic carrier; and a toner that rotates within the storage container and supplies the magnetic toner stored in the storage container to the vicinity of the developer carrier roll. A developing device comprising a toner supplying means, wherein the toner supplying means is provided with an elastic member having a length that contacts the bottom of the storage container.