JPS6271984A - Developing device - Google Patents

Abstract

PURPOSE:To carry selectively only non-magnetic toner to a developing area by forming a developer flow regulating means consisting of a magnetic body. CONSTITUTION:Since the plate-like developer flow regulating plate 22 formed by a magnetic body is arranged on the developer outlet of a developer storing container 21, the lines of magnetic force from a magnetic roller 23 are always converged into the flow regulating plate 22 even if magnetic poles constituting the magnetic roller 23 are changed by the rotation of the magnetic roller 23. An ear-like magnetic brush formed by a 2-component developer 24 consisting of toner 26 and carrier 27 is formed between the magnetic poles of the magnetic roller 23 and the flow regulating plate 22. The magnetic brush controls the developer 24 so that the carrier 27 is prevented from being carried through the flow regulating plate 22 and only the toner 26 reaches the developing area.

Description

[Detailed Description of the Invention] [Summary] A developing device used in an electrophotographic device or an electrostatic recording device, which selectively applies only non-magnetic toner to a developing area where a latent image carrier and a developing roller face each other. A developing device that can be transported.

[Industrial application field]

The present invention relates to a developing device used in an electrophotographic device or an electrostatic recording device, and in particular, it selectively applies only non-magnetic toner to a developing area where a latent image carrier formed around a recording drum and a developing roller face each other. The present invention relates to a developing device that can be conveyed to

After uniformly charging the recording drum with a latent image carrier formed around it made of a photoconductive layer such as selenium (Se) using a corona discharger, image information is transferred to the latent image carrier. An electrostatic latent image is formed by performing exposure corresponding to . Furthermore, electrophotographic recording devices that develop the electrostatic latent image by applying toner to it using a magnetic brush developer are widely used in copying devices and the like.

When developing using a two-component developer consisting of non-magnetic toner and magnetic carrier in the developing device of such a recording device, only the non-magnetic toner is selectively transferred to the developing area, especially when performing color recording. There is a need for a developing device that is capable of carrying out clear color recording by being conveyed by the developer.

[Prior Art] FIG. 2 shows a schematic diagram of a developing device using a conventional two-component developer.

As shown in FIG. 2, the conventional developing device consists of a carrier 1 made of magnetic particles and a toner 2 made of non-magnetic colored resin powder.
A developer storage container 4 containing a developer 3 comprising:
is provided. Inside the developer storage container 4, there is a non-magnetic sleeve 5 that rotates in the direction of arrow A; A developing roller 7 consisting of a magnetic roller 6 having a plurality of magnetic poles is provided.

Further, a spike cutting blade 8 made of a non-magnetic metal plate or the like is installed in the developer storage container 4 to regulate the height of the spikes of the developer 3 attached to the surface of the developing roller 7 to a predetermined size.
Further, a developer scraping blade 9 made of a non-magnetic resin plate or the like is provided for scraping off the developer 3 that has not been developed but has adhered to the surface of the developing roller rough and returned to the storage container 4.

To explain the operation of such a developing device, the developer 3 contained in the developer container 4 is attracted to the surface of the sleeve 5 by the magnetic force of the magnetic roller 6. Here, as shown in FIG. 3, assuming that the magnetic roller 6 rotates along the direction of the arrow B and the sleeve 5 rotates along the direction of the arrow, the developer 3 consisting of the toner 2 and the carrier L is The ears are conveyed in the direction of arrow A while performing rotational movement according to the rotation of the magnetic roller 6.

As shown in FIG. 2, the developer 3 adsorbed in the form of a spike on the sleeve 5 moves along the direction of rotation of the sleeve 5 shown by the arrow A, and moves to the spike provided at the outlet of the developer storage container 4. It is defined to a predetermined thickness by the cutting blade 8, and is further conveyed along arrow A. The toner 2 is then supplied to the electrostatic latent image formed on the recording drum 1) in the development area where the transported developer 3 comes into contact with the recording drum 1) on which the latent image carrier 10 is formed. It is attached and developed.

After the development is completed, the developer 3 is further conveyed on the developing roller 7 and collected into the developer storage container 4. Further, the developer 3 is peeled off from the developing roller 7 by a developer scraping blade 9, stirred by a stirring means (not shown), and the amount of toner 2 consumed by development is replenished, and then the same operation as described above is carried out for development. The device repeats.

[Problem that the invention seeks to solve]

However, in such a developing device, the toner concentration of the developer has a large effect on the recording quality; high toner concentration causes background smearing, and low toner concentration causes images to become pale or undeveloped. Nagunari, and even carrier l
adhesion occurs.

Therefore, in such an apparatus, a toner concentration sensor must be provided to manage the toner concentration, and toner must be supplied in accordance with the toner concentration, making maintenance and management of the developing device complicated and problematic.

Furthermore, in such a two-component developer, since development is carried out by bringing the developer 3 into contact with the recording drum 1), there is a problem in that the surface of the recording drum 1) is rubbed by the carrier 1 and scratches occur.

Furthermore, as previously proposed by the inventors, the recording drum 1
) In the case of color recording, in which latent image formation and development steps are repeated multiple times during one rotation, the previously formed toner image may be destroyed during the second and subsequent stages of development, or color mixing may occur. It was inevitable that this would happen.

Incidentally, in such color recording, the present inventors have previously proposed a method in which a one-component magnetic toner is used for the second and subsequent stages of development.

However, since the above-mentioned one-component magnetic toner has a structure in which magnetic powder is added to colored resin powder, there is a problem in that clear color recording cannot be realized.

[Means for solving problems]

The developing device of the present invention includes a non-magnetic sleeve 25, a magnetic roller 23 that is enclosed in the non-magnetic sleeve 25 and rotates together with the non-magnetic sleeve 25, and a developing roller 28 that is disposed at a developer outlet 33 of the developer storage container 21. A developer flow regulating means 22 made of a magnetic material is provided opposite to the developer flow regulating means 22 , and the rotation direction of the non-magnetic sleeve 25 of the developing roller 28 is the direction in which the developer 24 is directed from the developer outlet portion 33 toward the latent image carrier 31 . do.

[Effect]

In the developing device of the present invention, a plate-shaped developer flow regulating plate 22 made of a magnetic material is provided at the developer outlet of the developer storage container 21, so that the magnetic roller 23 is configured by the rotation of the magnetic roller 23. Even if the magnetic pole changes, the flow regulating plate 2 remains constant.
A two-component developer 2 consisting of toner 26 and carrier 27 is produced so that the lines of magnetic force from the magnetic roller 23 are focused on 2.
4 is formed between the magnetic pole of the magnetic roller 23 and the flow regulating plate 22, and the carrier 27 is prevented from being conveyed past the flow regulating plate 22 by this magnetic brush. Only the toner 26 reaches the developing area.

At this time, the non-magnetic toner 26 on the sleeve 25 has an electric charge due to frictional charging with the magnetic carrier 27 and frictional charging with the sleeve 25, and forms a layer of non-magnetic toner 26 on the surface of the developing roller 28 due to image force. This is how it was done.

〔Example〕

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

As shown in FIG. 1, the developing device of the present invention includes a developer container containing a two-component developer 24, which is a mixture of a toner 26 made of non-magnetic colored resin powder and a carrier 27 made of magnetic powder. At the developer outlet 33 of No. 21, a developer flow regulating plate 22 made of a magnetic material is provided at a position close to a developing roller 28 made of a non-magnetic sleeve 25 and a magnetic roller 23 contained therein.

The operation of such a developing device of the present invention will be explained.

The two-component developer 24 consisting of the toner 26 and carrier 27 described above is attracted to the surface of the developing roller 28 by the magnetic force of the magnetic roller 23 . At this time, both the magnetic roller 23 and the non-magnetic sleeve 25 rotate counterclockwise as shown by arrows C and D, and the developer 24 is also conveyed counterclockwise.

Here, since the developer 24 is conveyed in the same direction as the rotational direction of the magnetic roller 23, the magnetic roller 23 of the developer 24
The speed at which the developer 24 is transported by the sleeve 2
5, the conveyance speed is set higher.

As a result, the developer 2 adsorbed on the surface of the developing roller 28
4 is conveyed in the rotational direction of the non-magnetic sleeve 25 while performing rotational movement due to the movement of the magnetic pole of the magnetic roller 23. Further, due to the rotational movement of the developer 24 and friction with the sleeve 25, the toner 26 and the carrier 27 each have charges of opposite polarity. When the developer 24 reaches the flow regulating plate 22, the flow regulating plate 22 is a magnetic material and has a polarity opposite to that of the magnetic roller 23. become.

Further, the developer 24 begins to stay at the flow regulating plate 22, and finally moves upward along the flow regulating plate 22.
The developer container 2 slides on the surface layer of the developer 24 from the middle.
Reach the bottom of 1.

Further, when the developer 24 forms a magnetic brush between the flow regulating plate 22 and the sleeve 25, the non-magnetic toner 26 electrostatically adheres to the non-magnetic sleeve 25 due to image force.

Incidentally, the non-magnetic toner 26 adheres to the non-magnetic sleeve 25 even during transportation until it reaches the flow regulating plate 22 . Then, as the non-magnetic sleeve 25 rotates, it is transported to the developing area. If a developing bias is applied between the non-magnetic sleeve 25 and the recording drum 29 by the developing bias power source 32 in the developing region where the developing roller 28 and the recording drum 29 face each other, the peripheral latent image on the recording drum 29 will be retained. The toner 26 adheres to the electrostatic latent image formed on the body 31 and development is performed.

The one layer of toner not used for development is further transported and reaches the storage container 21.

Although not shown, since toner is consumed during development, new toner may be replenished by a known toner supply system.

According to this embodiment, together with the sleeve 25, the magnetic roller 23
Since the developer is rotated together, the magnetic brush of the developer rotates on its own axis, and the toner and carrier are more thoroughly stirred than when the developer is conveyed using only a non-magnetic sleeve. As a result, the toner is reliably charged in a short time during transportation, and a layer of toner can be easily formed on the surface of the nonmagnetic sleeve. In other words, it is possible to apply the present invention to high-speed recording, which is difficult to achieve with a developer conveyance system based on the rotation of only the non-magnetic sleeve 25.

Furthermore, since the developer conveyance speed due to the rotation of the non-magnetic sleeve 25 is higher than the conveyance speed due to the magnetic roller 23, the developer 24 does not stay at the developer conveyance entrance portion 30 of the storage container 21, and is transferred from this entrance portion 30. It will not leak outside.

In this embodiment, the magnetic roller 23 and the non-magnetic sleeve 25 are
Although the description has been made with both rotating in the same direction (counterclockwise), the rotation direction of the magnetic roller 23 does not matter as long as the non-magnetic sleeve 25 for conveying one layer of toner rotates counterclockwise. Furthermore, the direction in which the developer 24 is conveyed in the developer storage container 21 does not necessarily have to be counterclockwise; It is determined by the balance between

Furthermore, in addition to this embodiment, it is also possible to fix only the magnetic roller 23. In this case, the plate 22 is arranged so that a magnetic brush is formed between the sleeve 25 and the developer flow regulating plate 22.
It is preferable to adjust the magnetic pole of the magnetic roller 23 so that it is located at a position facing the .

Further, the developing bias voltage may be either direct current or alternating current.

Furthermore, in order to prevent the developer 24 from leaking from the developer transport entrance 32, it is more effective to make the gap between the developer storage container 21 and the developing roller 28 smaller than the particle size of the carrier 27 in the developer 24. .

Further, the toner conveyed to the developer storage container 21 after completion of development may be forcibly scraped off.

Further, the flow regulating plate 22 made of a magnetic material may have a magnetic pole, or a structure may be adopted in which a bias voltage is applied between the flow regulating plate 22 and the non-magnetic sleeve 25.

〔Effect of the invention〕

According to the developing device of the present invention, only the carrier of the two-component developer can be reliably and selectively blocked by the flow regulating plate, and only one layer of toner can be transported to the developing area, so that the device is simple. Therefore, a low-cost device can be obtained.

In addition, since there is no carrier in the development area, the surface of the recording drum will not be damaged, and since development is performed using only a single layer of toner, soft development can be obtained, and when used for color recording, it is clear and has good quality without image destruction or color mixing. This has the effect of being able to record.

Furthermore, since the magnetic roller is rotated, the toner can be sufficiently agitated, the toner can be charged easily and reliably in a short time, and high-speed recording is possible.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a developing device of the present invention, FIG. 2 is a schematic diagram showing a conventional developing device, and FIG. 3 is a schematic diagram showing the state of developer in the developing device. In the figure, 21 is a developer storage container, 22 is a flow regulating plate, 23 is a magnetic roller, 24 is a developer, 25 is a sleeve, 26 is a toner, 27 is a carrier, 28 is a developing roller, and 29 is a recording drum fist. , 30 is a developer inlet, 31 is a latent image carrier, 32 is a developing bias power source, 33 is a developer outlet, C is an arrow indicating the rotation direction of the magnetic roller, and D is an arrow indicating the rotation direction of the sleeve. be. 2 t gold θ month 0 t shif water reward 4 kan 6: whistle 1 fig. 1 - ri ff bj mo 7 (cover 1) - ri 1 deg rz fig. 2

Claims (3)

[Claims] (1) A developer storage container containing a two-component developer consisting of a magnetic carrier and a non-magnetic toner, a developing roller consisting of a rotatable non-magnetic sleeve and a magnetic roller included therein, the non-magnetic sleeve; and a developing device that transports the two-component developer along the surface of the developing roller by rotating one or both of the magnetic rollers, the rotatable non-magnetic sleeve (25) and the non-magnetic sleeve (25). a developing roller (28) consisting of a magnetic roller (23) contained in the developer container (21); and a developer outlet portion (33) of the developer storage container (21).
A developer flow regulating means (22) made of a magnetic material is provided opposite to the developing roller (28), and the direction of rotation of the non-magnetic sleeve (25) of the developing roller (28) is such that the developer (24) A developing device characterized in that the direction is directed from an exit port (33) toward a latent image carrier (31) on the surface of a recording drum (29). (2) The magnetic roller (2) of the developing roller (28)
3) The developing device according to claim 1, wherein the developing device is configured to rotate together with the sleeve (25). (3) The magnetic roller (2) of the developing roller (28)
3) The developing device according to claim 1, wherein only the portion 3) is fixed.