JPS6318381A - Developing device - Google Patents

Abstract

PURPOSE:To accelerate the improvement of developer stirring efficiency, to remove the deflection of the developer and to stably carry the developer with good balance by arranging a stirring guide plate on the down route of a developer circulation course. CONSTITUTION:The developer inverted by a developer regulating member 2 forms a circulation course (c) consisting of the down course in a developer container and an up course along the member 24. The stirring guide plate 29 is arranged on the down course so that the developer is moved in the longitidunal direction of a developer carrier member 22 by the plate 29. The developer circulated in the container 21 is branched by the guide plate 29 and dropped into a carrying and stirring member (screw) 44. Consequently, the deflection of the developer is removed, the stirring efficiency is improved and the uneven concentration is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention [Field of Industrial Application] The present invention relates to a developing device for developing a latent image formed by electrophotography or electrostatic recording.

[Conventional technology]

As this type of developing method, 1 using l-component magnetic toner is used.
Component development methods and two-component magnetic brush developer methods using two-component developers in which magnetic particles and toner are mixed have become mainstream.

Unlike the two-component developing method, the l-component developing method is simple and does not require a means to keep the developer concentration constant; however, it has poor transferability,
It has problems such as halftone reproducibility and stability of development characteristics against temperature and humidity.

Furthermore, since the toner generally contains a brown or black magnetic material, it is unsuitable for developing non-black colors.

On the other hand, the two-component magnetic brush development method enables stable development and is a simple development method suitable for non-black or full-color development, but there is a problem of developer deterioration due to changes in the surface of magnetic particles (spent toner, etc.). be.

Therefore, as a means to solve the above-mentioned problems of the two-component magnetic brush developing method, the present applicant proposed the invention of Japanese Patent Application No. 80-292847. The configuration of the developing device will be explained later, but (
1) The developer can be sufficiently stirred by stirring it in the screw section and further stirring it in the developing container 21. (2) Since the developer is rotating in the container 21, the regulating blade 2
(4) Since the developer is not compressed, developer deterioration does not occur. (3) When the developer is made compact, the developer capacity is reduced especially in the container 21 due to this circulation path, which has a large effect on developer deterioration. Since the developer can be sufficiently stored, the developer capacity can be increased.

[Problem that the invention seeks to solve]

The above invention can thus prevent deterioration of the magnetic particles (carrier) and extend the life of the developer. However, since there is no means for moving the developer circulating in the container 21 in the axial direction of the sleeve 22, the developer becomes uneven, resulting in poor stirring and further causing density unevenness.

The present invention provides a developing device that solves this problem. It is something.

Structure of the Invention [Means for Solving the Problems] The invention of Japanese Patent Application No. BO-292847, as illustrated in FIG. I! A developing device for developing a latent image, in which a developer container 21 containing a developer having toner particles 28 and magnetic particles 27 faces an electrostatic latent image carrier l, and the toner particles 28 are transferred to the electrostatic latent image. It forms a developing section that supplies the electrolatent image carrier l, and the container 2.
1, a developer carrying member 22 carrying and transporting developer to the developing section; and a regulating member located upstream of the developing section in the rotational direction of the developer carrying member 22 and spaced apart from the surface of the developer carrying member. The developer that has passed through the developer regulating member 24 portion, further passes through the developing section, and is conveyed on the developer supporting member 22 is transported downstream of the developing section. receive the developer, and transfer the developer to the developer container 21.
This developing device has transport stirring members (screws) 44 and 46 that transport the developer into the developer container 21 and mix it with the developer that has been reversed into the developer container 21 by the developer regulating member 24.

In the present invention, the developer reversed by the developer regulating member 24 of the developing device circulates through a path C that descends within the developer container 21 and ascends above the developer regulating member. A developing device characterized in that a stirring guide plate 29 is disposed in the descending path, and the developer is moved in the longitudinal direction of the developer carrying member 22 by the stirring guide plate. be.

[For production]

As mentioned above, the developer circulating in the container 21 is diverted by the guide plate 29 on its descending path and falls toward the transport stirring member (screw) 44, which eliminates the unevenness of the developer and improves the stirring performance. This improves the image quality and eliminates density unevenness.

〔Example〕

FIG. 1 is a sectional view of a developing device according to an embodiment of the present invention.

In this figure, an electrostatic latent image carrier l carrying an electrostatic latent image to be developed is a photosensitive drum on which an electrostatic latent image is formed by electrophotography, and is rotated clockwise as indicated by an arrow a. It is possible.

At the bottom of the developer device there is provided a bottom housing 36 which has a central partition 38 and forms a feed screw chamber 40 and a return screw chamber 42 which extend perpendicularly to the drawing. The central partition wall 38 is the container 21
As shown in FIG.
An opening 38b is provided on the front side to receive and transfer the developer between the feed screw chamber 40 and the return screw chamber 42.3
8b is a notch in the partition wall above the opening 38b on the front side, and also serves to cause the developer from above to fall into the return screw 42. A feed screw 44 that rotates in the counterclockwise direction of the arrow in the feed screw chamber 40 and a return screw 46 that rotates in the clockwise direction of the arrow in the return screw chamber 42 extend parallel to the sleeve 22 in its longitudinal direction. Rotatably supported.

A toner replenishment hopper 50a is provided in the upper part of the developing device, and toner is supplied to the return screw chamber 42 near the front end of the return screw chamber 42 in the figure through a replenishment port 50b. The feed screw 44 receives the developer not consumed during development from the sleeve 22 downstream of the developing section, and also serves to feed the developer from the back side of the drawing to the front side.
The return screw 46 receives the developer falling from the opening 38b, warms and stirs it with the toner supplied from the supply port 50b, and sends it from the front side of the drawing to the back side of the drawing, and closes the opening near the end on the back side of the drawing. It has the effect of passing it to the feed screw 44 via 38a.

The magnet 23 is fixed statically inside the sleeve 22 and remains stationary even when the sleeve 22 rotates. The magnet 23 cooperates with a first magnetic pole N1 which is a developing magnetic pole, a second magnetic pole St which cooperates with a blade 24 to be described later to control the amount of developer applied onto the sleeve 22, a third magnetic pole N2, and a third magnetic pole N2. A fifth magnetic pole that drops the developer from the sleeve 22 onto the screw 44 in cooperation with the fourth magnetic pole S3 and the i4 magnetic pole S3 that lift and transport the developer.
It has a magnetic pole S2. 34 is a photosensitive drum l and a sleeve 22
This is a power supply that applies an alternating electric field between the

Next, the stirring mechanism of the developing device of this embodiment will be explained.

When a developer that is a mixture of magnetic particles 27 and toner particles 28 is introduced into the container 21 and the sleeve 22 is rotated in the direction of the arrow, the developer rises from the bottom of the container 21 in a direction along the surface of the sleeve 22. It reaches the vicinity of the blade 24. Therefore, a part of the developer passes through the gap between the tip of the blade 24 and the surface of the sleeve 22 together with the toner and is transported to the developing section.

On the other hand, the developer that has not passed through the blade 24 rises along the inner surface of the blade 24, hits the earthen wall of the developer container 21, turns around, and descends by gravity on the outside of the developer upward path to the lower part of the container 21. It then rises near the sleeve 22 again and repeats the above operation, circulating as shown by arrow C.

During the repetition of the above circulation operation, the magnetic particles that turn around and fall near or in front of the blade 24 take in toner particles from the outer toner layer, and as the sleeve 22 rotates, they circulate in this way. By this,
The toner 28 is charged by friction between the magnetic particles 27 and the surface of the sleeve 22 .

The present invention is to provide a stirring guide plate 29 in the circulation section as shown in FIG. The stirring guide plate 29 is provided in the downward path of the circulating section within the developer container 21. As shown in FIG. 2, the attachments are arranged side by side on the side wall surface of the container 21, facing in different directions with respect to the axial direction of the sleeve 22. Further, it is preferable that the part of the stirring guide plate 29 closest to the sleeve 22 be at least 8 meters away from the sleeve 22. This is a position that is not affected by the magnet 23 in the sleeve and that This is to prevent the stirring guide plate 29 from acting on the developer being conveyed.

By arranging the stirring guide plate 29 as described above, the developer in the developing container 21 is stirred and conveyed while being circulated. Furthermore, since the amount of surface printing acting on the guide plate 29 changes automatically depending on the amount of developer, the amount of conveyance can also be adjusted.

As the sleeve 22 rotates, the toner particles and magnetic particles that have not been consumed for development reach the vicinity of the fifth magnetic 8iS2 magnetic pole. Since a repulsive magnetic field is formed between the fifth magnetic pole S2 and the fourth magnetic pole S3, the attractive force to the sleeve 22 disappears.
The developer falls into the screw chamber 40 due to gravity and is stirred by the feed screw 44. Since the feed screw 44 rotates counterclockwise as shown, the agitated developer is sucked up by the fourth magnetic pole S3 and is stirred by the feed screw 44. It returns to the container 21 transported by the magnetic pole N2. The angle θ between the fourth Fi1 pole S3 and the fifth magnetic pole S2 when viewed from the rotation center of the sleeve 22 is
Preferably, the temperature is within 120 degrees, so that the developer is sufficiently drawn into the container.

The developer collected in the container 21 repeats the process of being coated on the sleeve 22 again by the above-mentioned circulation action within the container 21. During the circulation, a part of the developer passes through the front opening 38b of the central partition wall 38. It passes through and falls and enters the return screw chamber 42. Inside the return screw chamber 42, the developer that has not been subjected to the above-mentioned development is mixed and stirred by the return screw 46 and sent from the front side of the drawing to the back side of the drawing, and is sent to the opening 38.
The receiver is passed into the feed screw chamber 40 at step a. In the feed screw chamber 40, the developer is mixed and agitated with the developer described above by the feed screw 44, and is sent from the back side to the front side in one drawing. A portion of the agitated developer that has come to the central partition wall 38 side by the feed screw 44 while being fed is lifted by the fourth magnetic pole S3 and returned to the container 21.

The amount of toner consumed by development is stored in the toner supply port 50b.
The developer supplied from the developer and dropped through the opening 38b;
The mixture is stirred and mixed by the return screw 46 and sent to the back side of the drawing, and then sent into the feed screw chamber 42.

In the present invention, by providing the stirring guide plate 29 in the developer container 21 as described above, the developer in the descending path of the circulation path C is divided by each guide plate 29 as shown in FIG. 40, and the developer in the developer container 21 is stirred with sufficient efficiency. Since the developer is conveyed while being stirred in the axial direction of the sleeve, the developer is not biased and uneven development does not occur.Furthermore, the amount of conveyance is automatically adjusted by dividing the flow as described above, so for example, if the developing device is tilted, Transport is carried out in a well-balanced and stable manner. In addition, the stirring guide plate 29 does not apply pressure resistance or other load to the circulating developer, so it does not deteriorate the magnetic particles.The stirring guide plate 29 is simply a plate member attached to the wall of the developer container. It can be obtained with just a simple configuration.

C. Effects of the invention As mentioned above, the developer that is mixed and stirred by the conveyance screw is magnetically attracted and carried by the developing sleeve, and a part of it is conveyed to the developing section, and the remaining developer is stored in the developing container. In the two-component magnetic brush developing device in which the developer is cyclically refluxed to the mixing agitation conveying member, a stirring guide plate is provided in the descending path of the developer circulation path, thereby helping to improve the agitation efficiency of the developer, Furthermore, it is possible to eliminate the deviation of the developer and to perform the conveyance in a well-balanced and stable manner.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view illustrating a developing device of the present invention, and FIG. 2 is a perspective view of a stirring guide plate of the present invention. FIG. 3 is a perspective view of the central partition inside the developer container. l...Latent image carrier (photosensitive drum), 21...Developer container (container), 22...Developer holding member (sleeve)
, 24... Regulation blade, 29... Stirring guide plate, 44, 46... Conveyance stirring member (screw).

Claims (1)

[Claims] (1) A developing device for developing an electrostatic latent image on an electrostatic latent image carrier, comprising: a developer container containing a developer having toner particles and magnetic particles; and the electrostatic latent image carrier. a developer carrying member facing each other to form a developing section for supplying toner particles to the electrostatic latent image carrying member, and carrying and transporting developer from the container to the developing section; a developer regulating member located upstream of the developing section in the rotational direction and having a regulating section tip spaced apart from the surface of the developer carrying member; and a developer regulating member that passes through the developer regulating member and further passes through the developing section. receives the developer conveyed on the developer carrying member downstream of the developing section, conveys the developer into the developer container, and directs the developer into the developer container by the developer regulating member. In the developing device, the developer is provided with a conveyance stirring member that mixes the developer that has been reversed, and the developer that has been reversed by the developer regulating member has a path descending within the developer container and a path on the developer carrying member. A circulating path is formed by the ascending path, and a stirring guide plate is disposed in the descending path, and the stirring guide plate moves the developer in the longitudinal direction of the developer carrying member. Characteristic developing device.