JPS645294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device, and more particularly to a developing device used in an electrostatic copying machine or the like to apply toner particles to an electrostatic latent image to form a developed image.

As is well known to those skilled in the art, a developing device used in an electrostatic copying machine or the like to apply toner particles to an electrostatic latent image to form a developed image is composed of a suitable member such as a rotating sleeve member. A developer application mechanism including a developer holding member and a toner particle supply mechanism are provided. Generally, a permanent magnet is disposed within the developer holding member, and the developer consisting of, for example, magnetic carrier particles and toner particles is moved onto the surface of the developer holding member by the action of the magnetic field formed by the permanent magnet. The developer is magnetically attracted and held, thus forming a magnetic brush of the developer on the surface of the developer holding member. The developer magnetic brush formed on the surface of the developer holding member is brought into contact with the surface of the member on which the electrostatic latent image to be developed is formed in the development area,
This applies toner particles to the electrostatic latent image and develops it into a visible image. The toner particle supply mechanism for supplying toner particles consumed by the development of the electrostatic latent image generally includes a toner particle container having a toner particle discharge opening, and a toner particle receptacle disposed at the toner particle discharge opening. and a rotating toner particle supply roller. The rotating toner particle supply roller is located opposite to the developer holding member in a toner particle supply area located downstream of the development area when viewed in the direction of movement of the surface of the developer holding member, and is located within the toner particle container. The contained toner particles are supplied to the surface of the developer retaining member via the surface of the rotating toner particle supply roller. More specifically, the toner particles contained in the toner particle reservoir are conveyed from the toner particle reservoir by being held on the surface of a rotating toner particle supply roller, and the toner particles are conveyed from the toner particle reservoir by the rotating toner particle supply roller holding the toner particles. A developer magnetic brush formed on the surface of the developer holding member contacts the exposed surface of the developer holding member, and thus toner particles are supplied from the exposed surface of the rotating toner particle supply roller to the surface of the developer holding member.

Therefore, the conventional developing device as described above has
Due to various phenomena such as toner particles clogging the surface of the rotating toner particle supplying roller, toner particles are not transferred from the surface of the rotating toner particle supplying roller to the surface of the developer holding member sufficiently quickly and smoothly;
Therefore, it has been found that there is a problem to be solved in that there is a tendency for so-called under-development phenomena to occur due to a shortage of toner particles.

The present invention has been made in view of these facts, and its main purpose is to ensure that toner particles are always stably transferred from the surface of the rotating toner particle supply roller to the surface of the developer holding member in a sufficiently rapid and smooth manner. Therefore, it is an object of the present invention to provide an improved developing device that can stably perform good development without causing insufficient development due to lack of toner particles.

As a result of intensive research and experiments, the present inventors have discovered that toner particles of the same polarity as the charged polarity of the toner particles held on the surface of the developer holding member are supplied to the rotating toner particle supply roller with respect to the developer holding member. When a bias voltage for supplying toner particles is relatively applied, the movement or supply of toner particles from the surface of the rotating toner particle supply roller to the surface of the developer holding member is promoted by the action of the bias voltage for supplying toner particles. It has been found that toner particles can always be stably, sufficiently quickly and smoothly supplied without causing phenomena such as clogging of toner particles on the surface of the toner particle supply roller.

That is, according to the present invention, a developer applying mechanism includes a developer holding member that holds developer containing toner particles on its surface, a toner particle container having a toner particle discharge opening, and a toner particle container disposed in the toner particle discharge opening. a toner particle supply mechanism having a rotating toner particle supply roller provided therein, the toner particles accommodated in the toner particle storage container passing through the surface of the rotating toner particle supply roller to the developer holding member; In a surface-supplied developing device: Toner particles having the same polarity as the charged polarity of the toner particles held on the surface of the developer holding member are applied to the rotating toner particle supply roller with respect to the developer holding member. The toner particle supply bias voltage applying means is provided for relatively applying a supply bias voltage to promote the supply of toner particles from the surface of the rotating toner particle supply roller to the surface of the developer holding member. A developing device with features is provided.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in more detail to FIG. 1, which illustrates one embodiment of a developing device improved in accordance with the present invention.

The illustrated developer device, indicated generally by the numeral 2, includes a developer housing 8 defined by a lower dish-shaped plate 4 and an upper cover plate 6. The lower part of the developer housing 8 constitutes a developer container 12 containing a developer 10, which may be a so-called two-component developer consisting of, for example, magnetic carrier particles and toner particles. An opening 14 is formed in the front surface of the developer housing 8, and the developer housing 8 also has an opening 14 formed therein.
An opening 18 that is closed by a door 16 that can be opened and closed is formed on the top surface of the housing.

A developer application mechanism 20 is provided within the developer housing 8.
is installed. Further, within the developer housing 8, a magnetic brush length setting member 22, which is positioned in relation to and around the developer application mechanism 20,
toner particle supply mechanism 24, developer peeling member 26,
A rotating stirring mechanism 28 is also provided.

The developer application mechanism 20 in the illustrated example includes:
The developer holding member 32 includes a rotating sleeve member rotatably mounted and rotationally driven in the direction shown by an arrow 30, and a stationary permanent magnet 34 disposed within the developer holding member 32. There is. The stationary permanent magnet 34 is roll-shaped and has six circumferentially spaced magnetic poles on its periphery, ie, three south poles and three north poles located alternately.

The magnetic brush length setting member 22 has a corner portion indicated by a number 22a that is in contact with the surface of the developer holding member 32.
The magnetic brushes formed by the developer 10 located close to each other at a distance _l1 , which is preferably about 0.5 to 3.0 mm, and held on the surface of the developer holding member 32 as will be mentioned later. Set the grain length to the required length. Such a magnetic brush grain length setting member 22
In order to finely adjust the distance _l1 as necessary, for example, in FIG. It is attached to the section.

The toner particle supply mechanism 24 includes a toner particle container 36 and a rotating toner particle supply roller 38 . The container 36 has a toner particle replenishment opening 39 at the top and a toner particle discharge opening 41 at the bottom. A large number of recesses or grooves are formed on the surface of the roller 38, which is rotatably attached to the toner particle discharge opening 41, by knurling, for example. This roller 38 is attached to the surface of the developer holding member 32 at or near an angular position where one of the plurality of magnetic poles, particularly the N pole, of the stationary permanent magnet 34 of the developer application mechanism 20 is located. It is preferable that they be placed closest to each other.
Utility model registration application dated July 15, 2017 (Name of invention: Magnetic brush developing device equipped with toner particle supply mechanism)
Please refer to the specification]. Developer holding member 32
The distance l ₂ between the surface of the developer holding member 32 and the surface of the roller is generally conveniently larger than the distance l ₁ between the surface of the developer holding member 32 and the magnetic brush length setting member 22 by about 0.3 to 2.0 mm. Roller 38 is preferably rotationally driven in the direction indicated by arrow 40 such that toner particles 42 in container 36 are sequentially transferred to roller 38.
The rollers are carried out from the container 36 to the exposed surface of the roller 38 (ie, to the lower half of the surface of the roller 38) while being accommodated in a number of recesses or grooves present on the surface of the roller 38. Such toner particles 42 are then supplied from the exposed surface of roller 38 to the surface of developer retaining member 32, as will be discussed later. To replenish the toner particles 42 into the container 36 itself, open the door 16 provided on the top surface of the developer housing 8 and load the toner particles 42 into the container 36 through the opening 18 and the toner particle replenishment opening 39. carried out by.

The developer stripping member 26 fixed at a predetermined position within the developer housing 8 has a tip 26a that is close to or in contact with the surface of the developer holding member 32, and as mentioned later, the tip 26a is attached to the developer holding member 32. 32
By acting on the developer 10 present on the surface of the developer holding member 32, the developer 10 is removed from the surface of the developer holding member 32.
Make sure to remove it.

The rotary agitation mechanism 28 can be configured, for example, from a rotary agitation member that is rotatably mounted and rotationally driven in the direction shown by the arrow 44.

The developing station 2 as described above is arranged, for example, on the circumferential surface of a rotating drum 46 (only a portion of which is shown) that is rotatably mounted in an electrostatic copying machine housing (not shown). Electrostatic photoreceptor 4
8 (also only a portion of which is shown), a developing device for applying toner particles to an electrostatic latent image formed by any suitable method known per se to develop it into a visible image; used as. In this case, the developing device 2 is installed so that the opening 14 formed on the front surface of the developing housing 8 faces the photoreceptor 48, as shown in FIG. The distance l ₃ between the developer holding member 32 and the surface of the developer holding member 32 is set to a required value. This interval l ₃ is
At one time, the distance l ₁ between the surface of the developer holding member 32 and the magnetic brush length setting member 22 is 0.3 to
It is convenient that the distance is approximately 0.7 mm larger and substantially the same as or slightly smaller than the above-mentioned distance l ₂ between the surface of the developer holding member 32 and the surface of the roller 38 .

The developing device 2 is connected to the arrow 30 of the developer holding member 32.
Depending on the rotation in the direction indicated by , the following actions are performed. First, in the developer drawing-up area indicated by symbol P, the developer 10 present in the developer container 12 is attracted and held on the surface of the developer holding member 32 by the magnetic attraction force of the permanent magnet 34. A magnetic brush 50 for the developer 10 is formed on the surface of the developer holding member 32 . Next, the magnetic brush 50 is made to have a desired length by the action of the magnetic brush length setting member 22.
Thereafter, in a developing area indicated by symbol D, the magnetic brush 50 is brought into contact with the surface of the photoreceptor 48 which is being rotated in the direction indicated by the arrow 52, and the electrostatic charge thus formed on the photoreceptor 48 is removed. Toner particles in magnetic brush 50 are applied to the latent image and the electrostatic latent image is developed into a visible image. After such a development action, in the toner particle supply area indicated by the symbol F, the magnetic brush 50, which has a large proportion of carrier particles because the toner particles are consumed by the development action, rotates in the direction shown by the arrow 40. contacting the exposed surface of rotating toner particle supply roller 38 , thus causing roller 38
Toner particles 42 present in a number of recesses or grooves formed on the surface of the magnetic brush 50 are supplied to the magnetic brush 50 . Next, in the developer peeling area R indicated by the symbol R, a permanent magnet 34 is placed in the developer peeling area R.
There is no magnetic pole. In addition to the fact that the magnetic field is extremely small even if it exists, the developer stripping member 26 acts on the magnetic brush 50 on the developer holding member 32, thereby removing the magnetic brush 50 from the surface of the developer holding member 32. The formed developer 10 is peeled off. The peeled developer 10 is removed by a developer peeling member 2
6 and falls toward the rotating stirring mechanism 28. The rotary stirring mechanism 28 stirs and mixes the developer 10 peeled off from the surface of the developer holding member 32 and the developer 10 present at the bottom of the developer container 12, and thus mixes the carrier particles and toner particles in the developer 10. In addition to uniformly mixing the toner particles, the toner particles are triboelectrically charged, for example, negatively.

If the developing device 2 has only the above-described configuration, the toner particles may clog the recesses or grooves formed on the surface of the rotating toner particle supply roller 38, causing the roller to fail. The movement of toner particles from the surface of 38 to the surface of developer holding member 32 (more specifically, the magnetic brush 50 formed on the surface of developer holding member 32) is hindered and cannot be carried out sufficiently quickly and smoothly; Therefore, the developer 10 is attracted and held on the surface of the developer holding member 32 in the developer drawing area P to form a magnetic brush.
The amount of toner particles therein tends to be insufficient and undesirable situations such as under-development phenomena tend to occur.

In order to solve such problems, according to the present invention, the rotating toner particle supply roller 38 is configured to adjust the charge polarity of the toner particles held on the surface of the developer holding member 32 to the developer holding member 32. same polarity,
Therefore, in the illustrated case, a toner particle supply bias voltage applying means for relatively applying a negative toner particle supply bias voltage is provided. In the illustrated embodiment, the toner particle supply bias voltage application means includes a first voltage source 54 and a second voltage source 56. The first voltage source 54 has a negative terminal connected to the rotating toner particle supply roller 38 , a positive terminal connected to the ground, and a first voltage source 54 .
A negative voltage (-V ₁ ) is applied to 8. On the other hand, the second
The voltage source 56 has a positive terminal connected to the developer holding member 32 and a negative terminal grounded, and applies a positive voltage (+V ₂ ) to the developer holding member 32 . Therefore,
In the specific example shown, the rotational toner particle supply roller 38 relative to the developer holding member 32 has an absolute value.
A toner particle supply bias voltage of V ₁ +V ₂ is applied. Such toner particle supply bias voltage promotes the movement of toner particles from the surface of the rotating toner particle supply roller 38 to the surface of the developer holding member 32 by electrostatic Coulomb force. Therefore, the occurrence of undesirable phenomena such as toner particles clogging in the recesses or grooves formed on the surface of the rotating toner particle supply roller 38 is prevented, and the rotating toner particles are always supplied stably, sufficiently quickly and smoothly. Toner particles are supplied from the surface of the roller 38 to the surface of the developer holding member 32, and therefore, stable and good development can be performed without causing undesirable phenomena such as insufficient phenomena due to insufficient toner particles. can.

In the illustrated example, the back surface of the photoreceptor 48 is grounded, as shown in FIG.
The positive voltage (+V ₂ ) applied to the photoreceptor 2 acts as part of the toner particle supply bias voltage between the rotating toner particle supply roller 38 and the developer holding member 32, and Biasing the developer holding member 32 to a positive voltage itself also functions as a well-known developing bias voltage. The voltage value applied by the first voltage source 54 and the voltage value applied by the second voltage source 56 vary somewhat depending on the characteristics of the toner particles themselves used, but in general,
The first voltage source 54 applies a voltage of |100| to |200|V to the rotating toner particle supply roller 38;
It is preferable that the voltage source 56 applies a voltage of |100| to |400|V to the developer holding member 32.

Although one specific example of the developing device improved according to the present invention has been described above in detail with reference to the accompanying drawings, the present invention is not limited to such specific example, and does not depart from the scope of the present invention. It goes without saying that various modifications and modifications can be made without having to do so.

[Brief explanation of the drawing]

FIG. 1 is a simplified sectional view showing a specific example of a developing device improved according to the present invention. 2...Developing device, 10...Developer, 20...Developer application mechanism, 24...Toner particle supply mechanism, 3
2... Developer holding member, 34... Stationary permanent magnet,
36... Toner particle container, 38... Rotating toner particle supply roller, 41... Toner particle discharge opening,
54...first voltage source, 56...second voltage source.

Claims (1)

[Scope of Claims] 1. A developer application mechanism including a developer holding member that holds developer containing toner particles on its surface, a toner particle container having a toner particle discharge opening, and a toner particle container disposed in the toner particle discharge opening. a toner particle supply mechanism comprising a rotating toner particle supply roller, wherein the toner particles contained in the toner particle storage container pass through the surface of the rotating toner particle supply roller to the surface of the developer holding member. In a developing device of the type in which the toner particles are supplied to the developer holding member, toner particles having the same polarity as the charged polarity of the toner particles held on the surface of the developer holding member are supplied to the rotating toner particle supply roller. The invention is characterized by comprising a toner particle supply bias voltage applying means for relatively applying a bias voltage for promoting the supply of toner particles from the surface of the rotating toner particle supply roller to the surface of the developer holding member. A developing device. 2. The toner particle supply bias voltage applying means includes a first voltage source for applying a voltage having the same polarity as the charging polarity to the rotating toner particle supply roller;
a second voltage source for applying a voltage having a polarity opposite to the charging polarity to the developer holding member;
The voltage applied to the developer holding member by the voltage source acts as part of the toner particle supply bias voltage between the rotating toner particle supply roller and the developer holding member, and The developing device according to claim 1, which acts as a developing bias voltage between the developer holding member and the electrostatic latent image to be developed. 3. The first voltage source applies a voltage of |100| to |200|V to the rotating toner particle supply roller, and the second voltage source applies a voltage of |100| to |400|V to the developer. The developing device according to claim 2, which applies an electric current to the holding member.