JPS59231561A - Developing device for electrostatic latent image - Google Patents

Abstract

PURPOSE:To select and reuse defective toner by providing a selecting mechanism which selects nonmagnetic toner defective in electrostatic charging near the exit of a conveyance path which stirs and conveys a developer. CONSTITUTION:A developer is supplemented from the opening 24a of a cylinder 24, moved to left while stirred with a coil spring 28 which rotates synchronizing with a rotating shaft, and stirred together with a developer entering from an opening 24b at a halfway point, and nonmagnetic toner and a magnetic carrier are charged by friction to give a charge to the nonmagnetic toner. Those developers are attracted by a magnet M and sent into a developing tank 21 through an opening 24c. Nonmagnetic toner defective in charging, on the other hand, falls in a small-diameter cylinder 35 from a cut 22b and is conveyed to right by a coil spring 39, and this toner is conveyed into the cylinder 24 from the cut 22a to strike a partition wall 44; and the toner is discharged and returned to the Q in the cylinder 24, where it is mixed with a developer again and stirred to be charge by friction.

Description

DETAILED DESCRIPTION OF THE INVENTION Part 1: The present invention is directed to an electrostatic latent image developing device used in an electrophotographic copying machine, etc., in particular, to develop an electrostatic latent image carried on an electrostatic latent image carrier in a non-magnetic manner. The present invention relates to an electrostatic latent image developing AA apparatus for developing using toner and a magnetic carrier.

Prior Art In an electrostatic latent image developing device that develops an electrostatic latent image using a two-component developer consisting of a mixture of non-magnetic toner and magnetic carrier, the developer is mixed and stirred in a tank. By doing so, the toner and carrier are triboelectrically charged, giving the toner a sufficient amount of charge for development.

However, as the developer becomes fatigued, the toner charging efficiency decreases, resulting in defective toner that is poorly charged and causes fog in copied images. This is particularly noticeable in developing devices that reuse toner collected by a cleaning device.

In order to solve the above problem, Japanese Patent Laid-Open No. 57-104956, Japanese Patent Laid-Open No. 57-167069, etc. provide means for removing defective toner, but in both of these methods, the device itself is defective. Since good quality toner (sometimes carrier) is also removed, there is a problem in that developer is wasted.

Furthermore, Japanese Patent Application Laid-Open No. 57-171371 proposes a method of mixing a charge control agent into the developer, but this method may have an adverse effect on the charge of good quality toner. Furthermore, since the charge control agent is always mixed into the developer in a constant amount, it is difficult to control the charge in accordance with the amount of defective toner.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and relates to an electrostatic latent image developing device that can select defective toner and make it reusable without wasting developer.

m-1 In order to achieve the above object, static tp, fk according to the present invention
The image developing device is an electrostatic latent image developing device that develops a static latent image using a two-component developer made of a mixture of non-magnetic toner and magnetic carrier, and includes a conveyance path for mixing and stirring the developer; The gist of the present invention is to include a band near the exit of the conveyance path, a sorting device for sorting out defective toner, and the sorting.

In Example No. 117j, an electrostatic latent image developing device (
10) roughly refers to the developing sleeve (1) installed in the developing section.
1), a magnetic roller (12) built into the developing sleeve (11), and a developer stirring mechanism provided within the developing sleeve (21). The developing sleeve (11) is made of a non-magnetic conductive material such as aluminum, and is formed into a cylindrical shape, and has a capacity of 10 cIrL/S in the counterclockwise direction.
It is installed so as to be rotatable in the counterclockwise direction at 30 r, plm in close proximity to the photoreceptor drum (1) which is rotatable at a circumferential speed of eC. The magnetic roller (12) has N around it.
It is in the form of a roll with the pole and south pole magnetized in sequence, and can be rotated at 200 Or, P, m in the same direction as the developing sleeve (11). That is, the developer has a diameter of 3
In the case of one dragon, a moving speed of about 10 cm/Sec in the clockwise direction along the circumferential surface of the developing sleeve (11) is obtained based on the rotational drive of the magnetic roller (12), and the rotational drive of the developing sleeve (11) is obtained. Approximately 5 cI in a counterclockwise direction based on
A moving speed of n/Sec is obtained, resulting in movement in the clockwise direction at a speed of about 5 crrL/Sec.

In addition, the outer periphery m1 located below the developing sleeve (11)
First and second developer scraping plates (14a) and (14b) made of a non-magnetic material having an I-pressing property, such as an appropriate synthetic resin phase or metal flakes, are attached to the developing sleeve (11).
It is attached to the support shaft (14) so that its tip comes into pressure contact with the forward direction opposite to the rotational direction and the usage direction that follows the rotational direction.

In such a configuration, the developer is mixed and agitated by nine developer agitating mechanisms, which will be explained in detail below, while being mixed and agitated by the packet roller (
The bucket (bucket) (20) (3) provided on the circumferential surface of the magnetic roller (12) receives the magnetic force t, 14i of the magnetic roller (12).
t (continuously conveyed and supplied to A+, and from this position (from A+ on the developing sleeve (11) approximately 5 cm/sec
The photoreceptor drum (1) is moved clockwise at a speed of
An electrostatic latent image previously formed on the surface of the toner by a known method is rubbed in a development gap, and the electrostatic latent image is developed into a toner image.

By the way, components that adversely affect the development of electrostatic latent images, such as undesirable materials such as dust mixed in the developer and solidified developer, may be present in the developer supplied onto the developing sleeve (11). If included, many of these components are not affected by the moving force based on the rotation of the magnetic roller (12),
By rotation of the developing sleeve (Jl), the developer is moved in a direction opposite to the moving direction of the developer, that is, in a counterclockwise direction,
The developer is scraped off from the circumferential surface of the developing sleeve (11) by the Sl developer scraping plate (14a) in the forward direction, and falls downward under its own weight. Therefore, these components are not transported to the development gap. Note that some of the developer scraped off by the first developer scraping plate (14a) is excessively supplied to the circumferential surface of the developing sleeve (11) and is affected by the moving force based on the rotation of the magnetic roller (12). Also included is developer that is hardly received and is moved counterclockwise. On the other hand, the developer after the electrostatic latent image is removed by the second developer scraping plate (14b) in the opposite direction from the developing sleeve (11).
) is scraped off from the circumferential surface of the developer tank (21) and returned to the developing tank (21) by falling downward under its own weight.

Next, the developer stirring mechanism in the electrostatic latent image developing device (10) will be described in detail as follows. 1st
As shown in the figure, a packet roller (20) is provided in the developer tank (21) so as to be rotatable in a clockwise direction. This packet roller (20) is driven to rotate around a rotating shaft (22) via a drive gear (26), and as shown in FIGS. 2 and 3, it is provided on the rotating shaft (22). A pair of rotating disks (29a) and (29b) are connected to each other, and a plurality of packets (3
1).

By being driven to rotate, the developer contained in the developer tank (21) is scooped up by the developer scooping packet (31) and installed in the developing section, specifically, one developing section. The developed sleeve (11) is then supplied onto the developing sleeve (11). Further, a developer stirring plate (32) is provided integrally with the packet roller (20) and inclined with respect to the rotating shaft (22).
) is provided. This stirring plate (32) is located inside the packet roller (20), and the stirring plate (32) is located inside the packet roller (20).
) are fixed in parallel to the bottom of the board. Therefore, when the packet roller (20) is rotated as described above, the developer in the developer tank (21) is moved by the stirring plate (32) in the axial direction of the rotating shaft (22), that is, in the photosensitive The body drum (1) is moved in a direction perpendicular to the moving direction of the body drum (1), and as a result, the developer discharge port (24
C) from willow.

The image agent receiver is sufficiently mixed and agitated while being conveyed in the direction toward the inlet (24b).

One end of the rotating shaft (22) is rotatably supported by a plate (17a) on the side of the developing device (10) via a bearing (23), and the other end is provided at the end of a cylinder (24). It is rotatably supported by a bearing (25b) and connected to a rotational drive means (not shown) by a drive gear (26) fixed to one end. And this rotating shaft (22)
A cylinder (24) is provided along the . This cylinder (2
4) forms a developer circulation path by using the internal space of the packet roller (20), and the rotating shaft (22)
While it has a cylindrical shape with the center at
) and a developer discharge port (24C). Note that this cylinder (24) is fixed to a fixed bearing (27) attached to another side plate (17b), and is also fixed to a rotating shaft (
22), with bearings (25a) and (25b) at both ends.
The rotary shaft (22) is rotatably supported via the rotary shaft (22). The opening (24a) is formed upward at the end of the cylinder (24) that protrudes outside the side plate (17b), that is, outside the developer tank (21) of the developing device (10), and is used to store new toner (supplemented developer). The developer collected by cleaning the surface of the photoreceptor drum (1) or the surface of the photoreceptor drum (1) is received at J1. Another opening (24b), (
24C) are formed in the developing tank (21) of the developing device (lO), and are formed at both ends of the developing tank (21) above and below, respectively. Note that the opening (24b) is formed at the end on the opening (24a) side. The number of openings may be increased as appropriate. Also, ni
Circle 1≧] (24) A spiral member is rotatably provided inside.

That is, a coil spring (28) is spirally wound around the rotating shaft (22) over the entire length inside the cylinder (24), and both ends of the coil spring (28) are connected to the rotating shaft (22).
, 22). This coil spring (28) rotates together with the packet roller (20) when the rotating shaft (22) is driven to rotate clockwise in FIG. It is moved in the axial direction, that is, in the left direction in FIG. 2, while stirring. Therefore, within the cylinder (24), the developer is transferred to the developer receptacle (24) by the action of the coil spring (28).
b) and is transported in the direction toward the developer discharge port (24C). This direction is opposite to the direction in which the developer in the developer tank (21) is transported by the action of the stirring plate (32).

Further, the rotating shaft (22) is a hollow cylinder body, and a small diameter cylinder (35) is provided inside thereof via bearings (36) and (37), and a cap (38) is attached to the left end portion of the small diameter cylinder (35). It is fixed to the cylinder (24). Therefore, the rotating shaft (22) is rotatable relative to the fixed cylinder (24) and the small diameter cylinder (35). Further, a coil spring (39) for conveying defective toner is provided inside the small diameter cylinder (35), and one end of the coil spring (39) is hooked to the circulation shaft (40), and the other end is a free end. There is. The circulation shaft (40) is rotatably supported via a bearing (41) for the rotating shaft (22) and a bearing (42) for the small diameter cylinder (35), and has a A drive gear (43) connected to a drive source is also provided.

The rotating shaft (22) and the small-diameter cylinder (35) will be described in detail below using FIG. 4 and FIG.

In FIG. 4, an opening (24) formed in a cylinder (24) is shown.
b) and (24C), the rotating shaft (22) has a pair of notches (z2) facing each other on its outer peripheral surface.
a), (22a) and (22b), (22b) are formed separately from each other. In addition, the notch (2
A magnet (24) for selecting defective toner is fixedly attached to the upper inner surface of the cylinder (24) facing the cylinder (24).

On the other hand, a small diameter Th (3
5), as shown in Figure 5, a%C, the opening Ll (35a) is opened downward (351) so as to face the openings (2za) and (22b) of the rotating shaft (22).
are each formed upward, and the opening (35a)
A partition wall (44) is provided near the. As will be explained in detail later, the small-diameter cylinder (35) forms a circulation path, and the defective toner that has been sorted out by the magnetic recess is transferred to the small-diameter cylinder (35) from the opening (35b) to the opening (35a).
) in the space (Pl), it is configured to be normally charged by °C.

The rotating disk (
29a) is fixed to one end of the rotating shaft (22), and another rotating disk (29b) is fixed to the fixed bearing (27) with a sintered metal j
It is rotatably mounted via a bushing (30) consisting of ^, etc. The packets (31) are screwed in large numbers in parallel to the bottom of the pair of packets (31) facing each other in this manner, and are fixed at an appropriate angle of inclination with respect to the rotating shaft (22). has been done. This stirring plate (
32) is a rotating disk (29a) whose rotating shaft (22) is rotationally driven in the clockwise direction in FIG.

When the packet (31) rotates together with (29b), it rotates together, stirring the developer in the rotational direction outside the circle 1 (24) and axially (
33) into the bucket) (31)
A large number of items are attached at a constant angle of inclination by screwing them into place at the corners.

In the developer agitation mechanism having the above configuration, the developer is transported through the opening Cz4 of the cylinder (24). a) is replenished from the cylinder (24), stirred in the direction of rotation within the cylinder (24) by the coil spring (28) rotating in synchronization with the rotating shaft, and moved to the left, and on the way, the cylinder (24) is fed through the opening (24b). The non-magnetic toner and the magnetic carrier are triboelectrically charged during this time, giving the non-magnetic toner an amount of charge suitable for development. When the magnetic carrier is transported near the magnet (Iv4) installed on the inner wall of the cylinder (24), the magnetic carrier is attracted by the magnet (■) and moves along the inner wall of the cylinder (24).At this time, it is normally charged. Since the non-magnetic toner is electrostatically attracted to the magnetic carrier, it moves along the inner wall together with the magnetic carrier and is sent into the developer tank (21) through the opening (24C). Since the non-magnetic toner is not attracted to the magnetic carrier, it is inserted into the opening (35b) through the notch (22b) of the rotating shaft (22).
) falls into the smaller diameter cylinder (35).

The poorly charged toner that has fallen into the small diameter cylinder (35) is removed by a coil spring (3) that rotates in synchronization with the circulation shaft (40).
9) in the small-diameter cylinder (35) to the right in the 2171st position, and is conveyed into the cylinder (24) through the opening (35a) through the notch (22a) on the rotating shaft (22).

Here, since the small-diameter cylinder (35) is provided with a partition (44), all of the transported and poorly charged toner is discharged.

The poorly charged toner returned to the space (Ql) inside the cylinder (24) is triboelectrically charged by being mixed with the developer and stirred, and then sorted by a magnet.

In this way, the poorly charged toner in the developer is stored in the developer tank (zt
), it circulates between the space fil in the small diameter cylinder (35) and the space fQ in the cylinder (24) until it is properly charged.

The developer that has been properly charged and sent into the developer tank (21) from the opening (24c) of the cylinder (24) is transferred to the rotating shaft (22).
) The stirring plate (32) rotates in synchronization with the cylinder (2
4) It is moved to the right while being stirred in the rotational direction outside, and is circulated and conveyed along the rotating shaft (22), while a part of it is scooped up by the bucket l-(31) and is placed at fA1 in Fig. 1. It is transported and supplied to the point.

The developer is magnetically attracted onto the developing sleeve (11) by the magnetic action of the magnetic roller (12), moves clockwise on the developing sleeve (11) as described above, and moves onto the photoreceptor drum (11). The electrostatic latent image is developed.The developer that was not scooped up into the packet (31) is
2), and is moved to the right while being stirred by the opening (24).
It enters into the cylinder (24) again from b). Incidentally, the developer is always stored in the developer tank (21) in an amount up to the level indicated by the two-dot chain line +Ql in FIG.

In the above embodiment, the selection of poorly charged toner was carried out by the magnetic force of the magnet (3), but the small diameter cylinder (35)
By applying a bias voltage between the inner coil spring (39) and the magnet M, the sorting function can be made even more reliable.

Effects As described above, the electrostatic latent image developing device according to the present invention imparts an electric charge to the non-magnetic toner by stirring the two-component developer consisting of a mixture of a non-magnetic toner and a magnetic carrier. The electrostatic latent image is developed using static 1.
In the latent image developing device, there is a conveyance path for agitating and conveying the developer, a sorting mechanism provided near the exit of the conveyance path for sorting out non-magnetic toner with poor charging, and a sorted belt α and a defective non-magnetic toner. Since the toner is equipped with a circulation path that sends the toner back to the vicinity of the entrance of the transport path and mixes it into the developer in the transport path again, it is possible to eliminate the poorly charged non-magnetic toner in the developer without reducing the amount of developer. Select only the normal zone ↑b,
The non-magnetic toner that is normally charged is not adversely affected, and there is no need for a device to collect and store the removed non-magnetic toner that has been improperly charged. Furthermore, by providing the circulation path within the conveyance path, there are many effects such as the ability to downsize the device itself.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electrostatic latent image developing device according to the present invention, and FIG.
The figure is a sectional view taken along the line nn of Fig. 1, Fig. 3 is a section of the developer stirring mechanism and a schematic perspective view, Fig. 4 is a sectional view showing the relationship between the rotating shaft and the cylinder, and Fig. 5a is the rotating shaft. 5b is a cross-sectional view taken along line mm in FIG. 5a, and FIG. 5C is a cross-sectional view showing the relationship between the small-diameter cylinder and the small-diameter cylinder, and FIG. 5C is a cross-sectional view showing the relationship between
・Packet roller, 21...Synthesis tank, 22-...
Rotating shaft, (2za), (22b)...notch, 2
4...Cylinder, (24a), (2413), (2
4C) -...Opening, 35-...Small diameter cylinder, (35a)
, (35b) -...Opening, 39...Coil spring, 40...Circulation shaft, 44...Partition, M...Magnet

Claims (1)

[Claims] 1. An electrostatic latent image is developed by stirring a two-component developer consisting of a mixture of a non-magnetic toner and a magnetic carrier to impart an electric charge to the non-magnetic toner, and developing an electrostatic latent image with the non-magnetic toner. In an electro-latent image developing device, there is provided a conveying path for agitating and conveying the developer, a sorting mechanism provided near the exit of the conveying path for sorting out non-magnetic toner with poor charging, and a separating mechanism for sorting out non-magnetic toner with poor charging. An electrostatic latent image developing device comprising: a circulation path for feeding the developer back to the vicinity of the entrance of the conveyance path and for mixing the developer into the developer in the conveyance path again. 2. The sorting mechanism includes a magnet, and while non-magnetic toner with insufficient charging is not attracted by the magnet, charged non-magnetic toner is attracted via a magnetic carrier that electrostatically attracts, thereby performing sorting. An electrostatic latent image developing device according to claim 1, characterized in that: 6. The electrostatic latent image developing device according to claim 1, wherein the circulation path is provided inside the conveyance path.