JPS6025074Y2 - Developer discharge device - Google Patents

Description

[Detailed description of the invention] The present invention is a device for discharging developer of a dry developing device used in an electrophotographic copying machine, an electrostatic printing machine, etc. (hereinafter referred to as an electrophotographic device), especially an old developing device. This invention relates to a device that uses a doctor blade to discharge the agent.

Dry type developing devices generally use a dry type two-component developer consisting of a carrier made of a magnetic material and a toner made of a low melting point thermoplastic resin base mixed with coloring dyes, pigments such as carbon black, etc.

This dry two-component developer is stirred in a developing device, and due to friction between the carrier and the toner, the toner is charged to a polarity opposite to the polarity of the charge on the electrostatic latent image holding material that is the object to be developed. A magnetic brush device configured to rotate the non-magnetic sleeve around a fixed magnet conveys the non-magnetic sleeve while adhering to the surface of the non-magnetic sleeve, and contacts the surface of the electrostatic latent image holding member.

In addition to these, there are those in which the non-magnetic sleeve is fixed and the magnet rotates, and there are those in which both the non-magnetic sleeve and the magnet are rotated.

Here, the charged toner is attracted to the charge on the electrostatic latent image holding member by Coulomb force and develops the electrostatic latent image.

In a developing device that uses such a two-component developer, toner is consumed each time an electrostatic latent image is developed, so in general, toner is replenished so that the mixture ratio of toner and carrier is always at the desired value. It is possible.

On the other hand, although the carrier is not consumed during development and is used repeatedly, it deteriorates due to stirring and the like, so it is necessary to replace it with a new one after a predetermined period of time or after a predetermined number of times of development.

This carrier replacement is performed by collecting the developer containing the old carrier from the developing device and then loading the developer containing toner and new carrier in an appropriate mixing ratio.

Conventionally, in order to recover developer containing such degraded old carrier, the developer was removed from the outside of the electrophotographic apparatus, and the developer was discharged by turning the developer storage container sideways or upside down. It was common.

Recently, various proposals have been made regarding developer discharging devices that can be operated without removing the developing device from the main body of an electrophotographic apparatus.

For example, Japanese Patent Application No. 54-10914 (Japanese Unexamined Patent Publication No. 55-10
No. 3564), when replacing the developer, the developing device is pulled out to the outside where it can be easily accessed, at least one of the non-magnetic sleeve or the magnetic bar is rotated in the normal rotational direction, and the other is attached to the doctor blade. has introduced a developer discharging device in which a discharging auxiliary plate is provided so that the tip thereof is almost in contact with the surface of the sleeve.

According to this discharge device, the developer is conveyed in the opposite direction to the conveyance direction during normal development by the rotation of at least one of the sleeve or the magnetic bar, and is scooped up onto the discharge auxiliary plate provided in the doctor blade section, and then developed. Expelled from the device.

By repeating this operation, most of the deteriorated developer can be discharged.

However, this type of device is complicated because the auxiliary discharge plate must be attached to the doctor blade each time the developer is replaced, and the developer may leak from the doctor blade and the auxiliary discharge plate. It was causing a problem.

The present invention is an improvement of the doctor blade part according to the invention of the patent application (Japanese Patent Application No. 54-10914) in order to eliminate the above-mentioned drawbacks, and aims to provide a simpler and more efficient developer discharge device. There is something to do.

The present invention includes a developer container, a magnet means provided in the container, a cylindrical sleeve made of a non-magnetic material that encloses the magnet means and holds magnetic developer on its outer surface, and a developing opening edge of the developer container. a doctor blade for regulating the amount of the magnetic developer, and at least one of the magnet means and the cylindrical sleeve is rotatably arranged to transport the developer in a predetermined direction and generate an electrostatic charge. In a dry type developing device for developing a latent image, the direction of conveyance of the developer can be reversed by rotating at least one of the magnet means and the cylindrical sleeve, and the doctor blade is arranged so that its tip is located at a predetermined distance from the cylindrical sleeve. The device is configured to be movable between a developer regulating position that is separated by a distance of According to the present invention, the developer is scraped off from the cylindrical sleeve and discharged to the outside of the developer container.

Since the present invention is constructed as described above, it not only eliminates the need for the troublesome work of removing the developing device, which was a disadvantage of conventional developer discharging devices, and also eliminates contamination caused by scattering of fine powder of the developer. This has the advantage that the discharging work can be performed more easily and quickly, and that the discharging efficiency can be improved.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view diagrammatically showing the structure of an example of a dry developing device embodying the present invention.

This embodiment shows a case where the present invention is applied to an electrophotographic copying machine.

The electrostatic latent image holding member 1 has a surface layer made of an insulating material or a photoconductive material on its outer periphery, and is mounted so as to be rotatable in the direction of arrow a with respect to the main body of a copying machine (not shown), and is used in a well-known electrophotographic method. An electrostatic latent image is formed on the surface layer.

In the present invention, the developing device 2 can be pulled out from the main body of the copying machine in a manner described later.

The magnetic brush 3, which constitutes the main part of the developing device 2, is composed of a cylindrical non-magnetic sleeve 4 and a magnetic bar 5 provided inside the sleeve, and each of these is arranged rotatably with respect to the developing container 6. Ru.

When developing an electrostatic latent image, the non-magnetic sleeve 4 is rotated in the direction of the arrow by a driving means (not shown), and the magnetic bar 5 is
is fixed at a predetermined rotational position, that is, at a position where at least one of the magnetic poles faces the electrostatic latent image holding section 1, by a locking means to be described later.

In this way, the developer 7 consisting of the magnetic carrier and toner stored in the bottom of the container 6 is caused to stick to the surface of the non-magnetic sleeve 4 in the form of spikes by the magnetic force of the magnetic bar 5, and this is applied to the non-magnetic sleeve 4. The electrostatic latent image holding member 1 is conveyed by rotation in the direction of the arrow mark and brought into contact with the surface of the electrostatic latent image holding member 1.
Developing the electrostatic latent image formed thereon.

At the lower edge of the opening of the container 6 facing the electrostatic latent image member 1,
Fixed part 8a, swinging part 8b and bending part or hinge part 8c
A doctor blade 8 is provided to prevent this from happening.

The fixing part 8a is fixed to the container 6 by a fixing screw 9a,
The swinging portion 8b is swingably mounted between the head of the screw 9b and the container 6 by a position regulating screw 9b.

By doing so, during development, that is, when the non-magnetic sleeve 4 is rotating in the direction of the arrow A, the swinging portion 8b acts to regulate the height of the magnetic brush tip, as shown in FIG. As shown, when the non-magnetic sleeve 4 rotates in the direction of the arrow A, the swinging portion 8b comes close to the surface of the non-magnetic sleeve 4 and acts to scrape off the magnetic brush ears.

In this example, the head of the fixing screw 9a protrudes, but if it is inserted so as to be located on the same plane as the fixing part 8a, ejection will be smooth.

Further, at a position adjacent to the magnetic brush 3 at the bottom of the container 6, a stirring member 10 is rotatably provided, which includes stirring blades for stirring the developer 7 and frictionally charging the toner.

The magnetic brush 3 is conveyed by the magnetic brush 3, and the developer 7 that has completed its developing action is scraped off from the non-magnetic sleeve 4 by a developer scraping plate 11 onto the bottom of the container 6.

This scraping plate 11 is pivotably attached to the container 6 via a pin 11', and its swinging tip comes into contact with or approaches the surface of the non-magnetic sleeve 4 due to its own weight.

In this example, at the position where the scraping plate 11 scrapes off the developer adhering to the non-magnetic sleeve 4, the adhesion of the developer to the non-magnetic sleeve 4 due to magnetic force is weakened.
In order to be able to scrape off easily, no magnetic pole is provided in the part of the magnetic bar 5 that faces the scraping position.

In this way, the developer on the non-magnetic sleeve 4, which has once completed its developing action, is scraped off to the bottom of the container 6, and stirred again to cause new developer 7 to adhere to the surface of the non-magnetic sleeve 4.

On the other hand, in the upper part of the container 6, a hopper 12 for storing toner for replenishment is formed by the container 6 and a plate 13, which is a toner receiver formed by a plate spring, and the entrance of the hopper 12 can be opened and closed with a lid 14. Configure.

Further, at the outlet of the hopper 12, a toner supply roller 15 is provided which rotates in the direction of arrow C at a predetermined speed in conjunction with the rotation of the non-magnetic sleeve 4.

This supply roller 15 is provided with a notch 15a for storing the toner in the hopper 12 and supplying it to the bottom of the container.
5a.

In this example, in order to prevent undesired replenishment of toner from the hopper 12 to the bottom of the container 6, especially from the gap between the container 6 and the plate 13, the toner receptacle is attached to the plate 1.
3, the container 6 constituting the hopper 12 has a length of 5 to 2
A rib ω is provided to protrude by about 0rrrrn, and this rib 6
Attach the sponge 16 to the bottom surface of a.

In this manner, the toner contained in the notch 15a is supplied to the bottom of the container 6 by the rotation of the supply roller 15, and the mixing ratio of the toner and the magnetic carrier in the developer 7 is always maintained at a desired value.

As described above, in this example, the toner receiver made of a leaf spring can hold the plate 13 in the notch 15a of the supply roller 15, so if all the toner stored in the notch 15a does not fall. However, since the toner receiver is forcibly scraped out when the plate 13 is engaged, it can be completely replaced.

Furthermore, since the toner is a powder, only the toner near the supply roller 15 is supplemented and a so-called bridge is formed in this area, and the remaining toner may not fall to the position of the supply roller 15. In this example, the toner receiver vibrates every time the plate 13 enters the notch 15a of the supply roller 15, so that the bridge can be broken and stable relocation can be achieved.

Furthermore, an opening is formed in the center of the container 6 to accommodate a developer containing a new magnetic carrier at a predetermined mixing ratio.
This can be opened and closed by a developer supply lid 17.

In this example, the supply M17 is integrally molded from a plastic material such as polypropylene, polyethylene, ABS, etc.
The container 6 is attached to the container 6 by a portion 17a, a thin portion 17b, and a lid portion 17c, and the lid portion 17c is configured to be rotatable around the thin portion 17b.

Further, the lid portion 17c is provided with an inner rib 17d and an outer rib 17e for replenishment on both sides thereof, and a recess 17f that forms a click mechanism together with the container 6 is further formed in the inner rib 17d. As a result, the lid portion 17c
It is constructed so that it can be opened and closed reliably.

By providing the inner rib 17d and the outer rib 17e in this way, the rotation angle (preferably about 60°) of the lid portion 17c can be restricted by the outer rib 17e and the mounting portion 17a, and the When storing the developer, the inner ribs 17d can effectively prevent tangling from both sides of the lid portion 17c.

In addition, since the lid portion 17c is rotated around the integrally molded thin portion 17b without using a hinge,
Replacement developer does not spill out from rotating parts.

Therefore, even an unskilled person can easily replace the developer without spilling it.

Next, the above-described holding mechanism for the magnetic brush 3 and the magnetic bar 5 will be described.
The locking means will be explained with reference to FIGS. 3 and 4.

FIG. 3 is a cross-sectional view of the magnetic brush 3 taken in the axial direction, and the non-magnetic sleeve 4 has flanges 2 at both ends.
0a and 20b are provided, and a drive shaft 21 is fixed to one of the flanges 20a.

The drive shaft 21 is rotatably attached to the developer container 6 via a bearing 22, and the drive shaft 21 protruding outside the container 6 has a drive gear 2 connected to a drive means (not shown).
3 is fixed.

Inside the non-magnetic sleeve 4, the magnetic bar 5 is attached to a bearing 25 provided on the flanges 20a, 20b.
The shaft 5a of the magnet bar 5, which is rotatably attached to the non-magnetic sleeve 4 by a and 25b and is pivotally supported by the other flanges 20a and 20b, supports the retaining plates 2 and 6 fixed to the container 6. It penetrates and protrudes to the outside.

A manual knob 24 is provided at the protruding end of the shaft 5a to manually rotate the magnet bar 5 when the developing device is pulled out from the copying machine body and the drive means and drive gear 23 are disconnected. .

A handle 27 used to pull out the developing device from the copying machine main body
is provided integrally with the holding plate 26 and is formed in the shape of a cover having a handle 27 and a continuous opening 27a on the lower surface.

The manual knob 24 is housed within the handle 27 and a bundle 28 is pivotally connected to the manual knob 24 via a shaft 29 .
8 is configured to be pulled up to the outside of the handle 27 during use.

The bundle 28 is constantly urged toward the handle 27 by a spring 30 (see FIG. 4).

When the bundle 28 is pulled up and rotated, the magnetic bar 5 rotates, but when the bundle 28 is located in the handle 27, the magnetic bar 5 cannot be rotated because it engages with the opening 27a, and the magnetic bar 5 is at a predetermined rotational position, that is, as explained in FIG. It will be locked in a position where there is no magnetic pole.

In the present invention, the developing device 2 is constructed so that it can be pulled out to the outside without being removed from the main body of the copying machine.

To this end, as shown in FIG. 5, a guide member 31 having a suitable cross-sectional shape is provided on the main body of the copying machine, and edges 32 and 33 that slide along this guide member 31 are formed at the bottom of the developing device 2. .

The guide member 31 also has the function of supporting the developing device 2 at its rear end when it is pulled out.

In order to make it possible to draw out or remove the developing device 2, a cover 34 is provided on the main body of the copying machine, and the cover is arranged so that the back surface becomes a horizontal top surface when opened.

A rib or protrusion 35 for positioning is provided on the back surface of the cover 34, and the protrusion 35 is used to position a developer collection box 36 having an appropriate strength and having an open top.

The developing device 2 can be supported in the drawn-out position by the collection box 36.

Alternatively, the collection box 36 in the drawn-out position may be supported in a cantilever shape only by the guide portion 31 described above.

Hereinafter, a description will be given of an operation for replacing deteriorated developer in the above-mentioned developing device.

First, prior to replacing the developer, in this example, the developing device 2 is pulled out to the position shown in FIG.

Next, the bundle 28 of the manual knob 24 is pulled up from the handle 27 and rotated within the opening 27a, thereby rotating the magnetic bar 5 in the opposite direction to the direction indicated by the arrow, that is, in the direction indicated by the arrow.

When the magnet bar 5 rotates in direction b, the non-magnetic sleeve 4 rotates together with the magnet bar 5 due to the magnetic force acting between the magnetic carrier on the non-magnetic sleeve 4 and the magnet bar 5 and the frictional force of the bearing 25av25b. .

Therefore, the developer on the non-magnetic sleeve 4 is transported as the magnet bar 5 rotates.

The developer on the non-magnetic sleeve 4 presses and bends the swinging part 8b of the doctor blade 8 due to its own weight, and is displaced until the tip of the swinging part 8b comes into contact with the surface of the non-magnetic sleeve 4.

Thereafter, while rotating in the direction of the arrow, the displacement state is maintained due to the developer's own weight, so the developer transported to the position of the doctor blade is scraped off by the swinging portion 8b, as shown in FIG. It is stored in the collection box 36 shown in FIG.

The portion of the non-magnetic sleeve 4 from which the developer has been scraped off re-adsorbs the developer remaining at the bottom of the container 6, and the same operation is repeated.

In this way, in this example, by rotating the magnet bar 5 in the direction indicated by the arrow, the non-magnetic sleeve 4 is rotated together by the magnetic force acting between the magnetic carrier and the magnet bar. The adhesion resistance of the developer onto the magnetic sleeve 4 and the conveying force of the developer due to the rotation of the non-magnetic sleeve 4 are increased, so that the developer can be efficiently and almost completely recovered.

To put new developer in and make it ready for development, first return the handle and fit it into the opening 27a of the handle 27, thereby locking the magnet bar 5 in a predetermined position.

Next, by attaching the developing device 2 to the main body of the copying machine and rotating the non-magnetic sleeve 4 in the direction of the arrow a, the developer is transported in the direction of the arrow and pushes up the swinging portion 8b of the doctor blade. Since it is regulated by the screw 9b and cannot be pushed up any further, the height of the spike of developer can be regulated to a predetermined position.

The doctor blade may be integrally molded from a plastic material such as ABS resin, and the hinge 8c may be made thinner so that the swinging portion 8b swings.Alternatively, the swinging portion may be made of lightweight metal and a separate hinge member may be used. It may be swingable relative to the fixed part.

In the former case, as the amount of developer decreases, the magnetic brush tip becomes smaller, and the swinging portion 8b becomes separated from the non-magnetic sleeve 4 due to self-reaction force, as shown in FIG.

In the latter case, even when no developer is deposited on the swinging portion 8b, the tip of the swinging portion 8b is bent about the hinge portion 8C, as shown in FIG. 2, and comes into contact with the non-magnetic sleeve 4.

Therefore, if a hinge is used for the hinge portion 8c, almost all of the developer can be discharged.

After replacing the developer, the developing device 2 is returned to the copying machine main body.
The magnetic bar 5 is not necessarily locked at a predetermined rotational position.

However, even if it is not at a predetermined rotational position, as the non-magnetic sleeve 4 rotates in the direction of the arrow when developing an electrostatic latent image, the magnet bar 5 also rotates together due to the magnetic force with the magnetic carrier. Therefore, within one rotation of the magnetic bar 5, the handle 28 engages with the handle 27 and is automatically locked at a predetermined rotational position.

In the above-mentioned embodiment, the non-magnetic sleeve is rotated when performing normal development, and the magnetic bar is rotated when discharging the developer, but the magnetic bar is fixed even when discharging the developer. However, the non-magnetic sleeve can also be rotated in the opposite direction to that for normal development.

In any case, in the present invention, when discharging the developer, it is only necessary to rotate at least one of the non-magnetic sleeve and the magnetic bar so that the developer is conveyed in the opposite direction to that in normal development. .

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view diagrammatically showing the configuration of an example of a developing device implementing the present invention, showing the case during development work, and FIG. 2 is a partial cross-sectional view showing the operating state of the discharging device of the present invention. , Fig. 3 is a cross-sectional view of the magnetic brush cut in the axial direction to explain the holding mechanism of the magnetic brush, Fig. 4 is an external view of the locking means of the present invention, and Fig. 5 is the entire discharge device of the present invention. FIG. 2 is an external perspective view showing an example of the configuration. DESCRIPTION OF SYMBOLS 1... Electrostatic latent image holding member, 2... Developing device, 3... Magnetic brush, 4... Non-magnetic sleeve, 5... ... Magnet bar, 6 ... Developer container, 7 ... Developer, 8 ... Doctor blade, 8a ... Fixed part, 8b ...・
- Swinging part, 8c...Bending part or hinge part, 9a
...Fixing screw, 9b... Position regulating screw, 10... Stirring member, 11... Developer scraping plate, 12... ...Hopper, 13...
...Toner receiver is plate, 15...Toner supply roller, 16...Sponge, 17...Developer supply lid, 20a, 20b... flange, 2
1... Drive shaft, 22... Bearing,
23... Drive gear, 24... Manual knob, 25a, 25b... Bearing, 26...
...Holding plate, 27...Handle, 27a...
...Handle opening, 28...Handle, 29...
... shaft, 30 ... spring, 31 ... guide support member, 32, 33 ... edge, 34 ...
. . . Cover of electrophotographic device, 35 . . . Positioning rib, 36 . . . Collection box.

Claims (1)

[Scope of utility model registration request] A developer container, a magnet means provided in the container, a cylindrical sleeve made of a non-magnetic material that encloses the magnet means and holds magnetic developer on its outer surface, and a cylindrical sleeve provided at the edge of the development opening of the developer container. and a doctor blade for regulating the amount of the magnetic developer, and at least one of the magnet means and the cylindrical sleeve is rotatably configured to convey the developer in a predetermined direction to develop the electrostatic latent image. In the dry developing device, the direction of conveyance of the developer can be reversed by rotating at least one of the magnet means and the cylindrical sleeve, and the tip of the doctor blade is separated from the cylindrical sleeve by a predetermined distance. The structure is movable between a developer regulation position and a developer discharge position in contact with the cylindrical sleeve, and the developer is transported in the opposite direction from the predetermined position and the doctor blade is set at the developer discharge position. A developer discharge device characterized in that the developer discharge device is configured to be able to scrape off the developer from the cylindrical sleeve and discharge it to the outside of the developer container.