JPS60130771A - Developing device - Google Patents

Abstract

PURPOSE:To increase the stability of the conveyance of a developer layer by a developer carrier and improve the effect of transfer control over toner particles by providing ruggedness to the developer carrier surface of a developing device which performs development in the presence of an oscillating electric field by using a two-component developer. CONSTITUTION:The layer of a developer consisting of magnetic carrier particles and toner particles is formed on the surface of the developer carrier 2, and the oscillating electric field is produced between an image forming body 1 and the developer carrier 2 by a bias power source 3, protection resistance 4, etc., to perform development. The surface of the developer carrier 2 is made ruggedness, so the developer layer is formed stably. Thus, toner particles are separated from the developer layer with the oscillating electric field produced between the developer carrier 2 and image forming body 1 to control the transfer to the image forming body 1 effectively.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrostatic latent image or a magnetic latent image formed on the surface of an image forming body by electrophotography, electrostatic recording, electrostatic printing, magnetic recording, or the like. Regarding the developing device of a recording device that attaches toner particles to an image, in particular, a layer of a so-called two-component developer in which magnetic carrier particles and toner particles are mixed is formed on the surface of a developer transporting carrier, and the developer is developed under an oscillating electric field. The present invention relates to a development device for depositing toner particles from a layer onto a latent image on an imaging member.

[Prior art]

As a developing device as described above, Japanese Patent Application Laid-Open No. 56-14445
No. 2, No. 57-139761, No. 57-147652
No. 58-48065 are known. By using a two-component developer, these developing devices 6° can more easily control the triboelectric charging of toner particles than those using a single-component developer for magnetic toner particles, and are less likely to cause agglomeration of toner particles. Therefore, it becomes easy to uniformly form a developer layer on the developer transport carrier m1, and furthermore, the transfer of toner particles from the developer layer to the image forming body can be easily controlled by the oscillating electric field. Therefore, toner particles are transferred from the developer layer to the image forming body under an oscillating electric field without bringing the developer layer into contact with the surface of the image forming body, thereby eliminating the sweeping that is likely to occur when the developer layer is brought into contact with the image forming body. This allows development to be performed without blurring the eyes. However, even with such a developing device, overlapping or edge effects may occur during development. When a two-component developer is used that has finer particles than magnetic carrier particles with a diameter of several tens to hundreds of micrometers or toner particles with an average particle diameter of more than ten micrometers, this tendency becomes more pronounced, and furthermore, the carrier particles become smaller. Adhesion to the image forming body is also likely to occur.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned problems in the conventional developing device, and by improving the developer transport carrier in the conventional developing device, which had a smooth surface. Yuto has discovered that the above-mentioned problems can be solved by increasing the stability of the transport of the developer layer by the agent transport carrier and by improving the effect of controlling the transfer of toner particles by the oscillating electric field.

[Structure of the invention]

The present invention involves forming a developer layer containing a mixture of magnetic carrier particles and toner particles on the surface of a developer transporting carrier, and adhering the toner particles from the developer layer to a latent image on an image forming member under an oscillating electric field. The developing device is characterized in that the surface of the developer transporting carrier has irregularities, and this configuration achieves the above object.

Hereinafter, the present invention will be explained in detail with reference to the drawings 11G.

FIG. 1 is a partial sectional view of a recording device showing an example of the developing device of the present invention, and FIGS. 2 and 3 are perspective views showing an example of the structure of a developer transport carrier, respectively.

In the figure, numeral 1 has an image forming layer made of a photoreceptor or dielectric material such as Se on its surface, and is charged (not shown).

A drum-shaped image forming body rotating in the direction of the arrow on which an electrostatic latent image is formed on the image forming layer by an exposure device etc.; 2 is a developer having irregularities on its surface as shown in FIGS. 2 and 3; It is a transport carrier. The depth of these irregularities is preferably in the range of 10 to 2000 μm, preferably 10 to 500 μm, and more preferably 500 μm or less, more preferably the carrier particle size or more, and especially when the carrier particle size is several tens of μm, the carrier particle size or more and 100 μm or less.

The developer transport carrier 2 shown in Fig. 2 is made of a non-magnetic material such as aluminum or stainless steel, and has stripe-like unevenness parallel to the axis with a width and height of approximately 50 to 2000 μm on the surface. The developer transport carrier 2 shown in FIG. 3 is also made of non-magnetic material and has a surface with a depth of 10 to 500 μm created by sandblasting.
The surface of the sleeve made of a similar non-magnetic material is coated with Ni or Ni-Or-B by the metal spray coating method (Metallicon method).
,C.

-Or-W,! A magnetic metal or metal alloy such as i'e -Or -B is blown into a sleeve to randomly form irregularities of about 10 to 2000 μm, or a similar sleeve is coated with the above-mentioned magnetic powder on the surface. The mixed resin layer is provided with an unevenness of about 10 to 2000 ltm. Among these, when the surface is made of metal, it is preferable to make the insulating convex metal semi-insulating by coating one surface with a resin or oxide film so that the unevenness of the surface does not disappear. The reason is that when the surface of the developer transport carrier 2 is provided with irregularities as described above, clogging does not occur during the formation of the developer layer, and the security of the developer layer is improved.
This is because, although the control of toner particle transfer by the oscillating electric field is improved, on the other hand, the application of a bias voltage that causes the oscillating electric field tends to cause insulation failure such as a lightning strike phenomenon.

3 is a bias power supply that applies a bias voltage to the developer transport carrier 2 via the holding resistor 4 and forms an oscillating electric field between the image forming body 1 whose base portion is grounded and the developer transport carrier 2;
is a magnet provided inside the W image portion conveyor 111 body 2. The magnet body 5 has a plurality of N and S magnetic poles arranged in the circumferential direction on its surface, and the N and S magnetic poles are normally magnetized to a magnetic flux density of 500 to 1500 Gauss.

In the illustrated developing device, the developer transport carrier 2 rotates in the direction of the arrow, the magnet body 5 rotates in the opposite direction of the arrow, and the developer is transferred to the developer reservoir 6 by the magnetic force of the N and S magnetic poles of the magnet body 5. is adsorbed to the surface of the developer transport carrier 2 in the form of magnetic carrier particles accompanied by toner particles, and the adsorbed developer is rotated in the same direction as the rotation direction of the developer transport carrier 2 by the rotation of the developer transport carrier 2 and the magnet body 5. The developer layer is formed by moving in the direction, and the layer thickness is regulated by a layer thickness regulating blade 7 made of a non-magnetic or magnetic material.

As described above, since the surface of the developer transport carrier 2 has irregularities, clogging at the position of the layer thickness regulating blade 7, which is often seen in the case of conventional smooth developer transport carriers, is prevented. As a result, the developer layer is stably formed. However, the present invention is not limited to the illustrated developing device.
The magnet body 5 is stationary and the developer layer is moved by the developer transport carrier 2.
, or as long as the developer layer moves in such a way that the layer thickness is regulated by the layer thickness regulating blade 7 and reaches the developing area A, the developer transport carrier 2 is moved in the opposite direction to the direction of the arrow. Even if it rotates in the direction of
Alternatively, the moving direction of the image forming body 1 and the moving direction of the developer layer may be opposite to each other. Even in these cases, the effect that the formation of the rice grains and the image side layer can be stably performed without clogging can be obtained. In addition, in the case where the magnet body 5 is kept stationary, in order to prevent the magnetic carrier particles from transferring from the developer layer to the image forming body 1 in the development area A, a magnetic carrier is placed on the surface portion facing the image forming body 1. It is desirable to make the magnetic flux density of one magnetic pole higher than that of other magnetic poles. This may be done by increasing the magnetization or by placing magnetic poles close to each other.

8 transfers the developer layer that has passed through the development area A to the developer transport carrier 2.
The cleaning blade 9 stirs the developer pool 91 in the developer pool 6 to homogenize the mixture of toner particles and carrier particles, and removes the developer pool crvcy from the surface of the toner paddy. The stirring roller 10 is
This is a toner supply roller that supplies toner particles from a toner reservoir 11 to a developing section 6. In the developing device of the present invention as described above, since the W5 image portion transport carrier 2 has irregularities on the surface, not only the formation of the developer layer is performed stably, but also the developer transport carrier 2 and the image Effective VC control for separating toner particles from the developer layer and transferring them to the image forming body 1 using the oscillating electric field formed between the forming bodies 1 allows the developer layer to be separated from the surface of the image forming body 1. Although the developing condition may be such that the image is brought into contact with the image forming layer, it is preferable that the developing condition is such that the image is not brought into contact with the image.

In the case of this non-contact development condition, the developer transport carrier 2 is kept at a surface gap of several tens to 2000 μm with respect to the image forming body 1, and the developer JvI is brought into contact with the surface of the image forming body 1 using the layer thickness regulating blade 7. It is preferable to form the layers in close layer thicknesses without causing any overlap. If the surface gap between the image forming member 1 and the developer transport carrier 2 is made too narrow, it will be difficult to uniformly form the developer layer on the surface of the developer transport carrier 2, and the toner particles will not be distributed in the development area A. If the surface gap is 2.
If it greatly exceeds 000 μm, even if a developer transport carrier 2 having an uneven surface is used, toner particle transfer control by the oscillating electric field will not be performed efficiently, and a sufficient developed density will not be obtained.

If the surface gap is in the range of several tens to 2,000 μm, preferably 10 to 500 μm, the developer layer can be uniformly formed on the surface of the developer transport carrier 2 with an appropriate thickness, and the oscillating electric field can be applied to the developer layer. It is possible to efficiently control the transfer of toner particles. In addition, when using non-contact development conditions, it is preferable to form a developer layer with a thinner and uniform thickness than under contact development conditions in order to prevent fogging and edge effects. It is particularly preferred that 2 has a magnetic layer as described in connection with FIG.

When the developer transport carrier 2 has a magnetic layer, N of the magnet body 5,
This has the effect of reducing variations in the thickness of the developer layer that tend to occur due to the arrangement of the S magnetic pole.

The oscillating electric field formed between the developer transport carrier 2 and the image forming body 10 in order to facilitate the separation of toner particles from the developer layer has a bias voltage l1Iit3 and an effective value of the alternating current component of the developer transport carrier 2 of 200 to 5000 V. , the frequency is 100 Hz
~10 kHz, preferably 300-4000v.

Preferably, a bias voltage of 1 to 5 kHz is applied, thereby exhibiting an effective field strength of 300 to 5000 V/ms. The bias voltage applied to the developer transport carrier 2 by the bias power source 3 is superimposed with a DC voltage of an appropriate magnitude having the same polarity as the potential of the non-image area of the image forming member 1 in order to prevent the occurrence of fogging. Of course it can be used.

In addition, the image forming body 1 and the developer transport carrier 2 are not limited to the illustrated example.
An oscillating electric field may be generated in the development area A by providing a wire electrode, a net electrode, or the like that does not impede the transfer of toner particles between the two, and applying a bias voltage thereto. In that case, it is also possible to superimpose a DC component on the bias voltage, apply a DC voltage to the developer transport carrier 2, or apply an oscillating voltage with a different frequency to the developer transport carrier 2. be exposed. The waveform of the alternating current component of the bias voltage is not limited to a sine wave, but may be a triangular wave, a rectangular wave, or the like.

Further, by appropriately setting the voltage, polarity, etc. of the DC component of the bias voltage, the present invention and the developing device can be applied not only to positive development but also to reversal development. In the case of reversal development, the DC component of the bias voltage is set to a voltage approximately equal to the accepted potential in the non-image background portion of the image forming member. Furthermore, the developing device of the present invention can also be applied to developing magnetic latent images by using toner particles containing a magnetic substance.

The developing device of the present invention is composed of a mixture of magnetic carrier particles with an average particle size of tens of micrometers to hundreds of micrometers and non-magnetic toner particles with an average particle size of tens of micrometers, similar to conventional two-component developers. .

Developers are also used, but in order to obtain high-quality images that reproduce delicate lines, dots, and differences in shading, we use toner particles with a weight average particle size of 1 to 20 μm and toner particles with a weight average particle size of 5 to 50 μm.
It is preferable to use a developer in which the magnetic carrier particles are mixed with magnetic carrier particles, and the magnetic carrier particles are insulating particles such as magnetic particles whose surfaces are coated with a resin film or resin particles containing dispersed magnetic particles. Particles are preferable because a high bias voltage can be applied to the developer transport carrier 2.

The insulating properties of the carrier particles are preferably 10 8 Ω or more, particularly 10 15 Ω cm or more in terms of resistivity. This resistivity is calculated by placing the particles in a container with a cross-sectional area of o, 5ocnL2 and tapping, then applying 1 Ky/K on the packed particles.
A load of crn2 is applied, and a distance of 100 mm is applied between the load and the bottom electrode.
This value is obtained by reading the current value when applying a voltage that generates an electric field of 0 V/α.If this resistivity is low, when a bias voltage is applied to the developer transport carrier,
Carrier particle [1! Charges are injected, making it easier for carrier particles to adhere to the surface of the image carrier, or for bias voltage breakdown to occur more easily.

According to the developing device of the present invention, as described above, the developer layer can be stably formed on the developer transport carrier 2, and the transfer of toner particles can be efficiently controlled by the oscillating electric field. Therefore, even if finely divided toner particles or carrier particles are used, the toner particles can be easily transferred from the developer layer to the latent image on the image forming member 1 under non-contact development conditions, thereby creating a high-quality image. can be reproduced.

Next, specific examples of the present invention will be shown.

〔Example〕

In the developing device shown in FIG. 1, the developer transport carrier 2 is made of a stainless steel sleeve having an outer diameter of 3011I111, and Ni is sprayed to a thickness of about 500 μm by the metallicon method, and the surface has irregularities of about 50 to 500 μm. The magnet body 5 was designed to rotate at 700 rpm in the direction of the arrow, with eight N and S magnetic poles having a magnetic flux density of 900 caus provided on the surface at equal intervals in the circumferential direction. The developer has a weight average particle size of 30 μm.
Insulating carrier particles with a specific resistance of about 1 x 10 Ωcm containing magnetic powder dispersed in a resin and M=,' f
Using a developer consisting of insulating nonmagnetic toner particles with an average particle diameter of 14 μm, the gap between the layer thickness regulating blade 7 and the developer transport carrier 2 was set to 400 μm, and the layer thickness was approximately 500 μm.
The developer layer was formed on the developer transport carrier 2. This developer transport carrier 2 has an image forming layer made of a shaped photoconductor 1JPO and is moved at a speed of 120 mm/se in the direction of the arrow.
The image forming layer rotates at a surface speed of c, and the non-image background potential -
A static ff[t of -500V to 50V.The bias power supply 3 applies a static voltage of 2 to the developer transporting carrier 2 so that the image forming member 1 on which a latent image is formed faces the surface with a distance M of 700 μm.
Development was carried out by applying a bias voltage of a superimposed alternating current voltage of kHz, 1 kV and direct current voltage of -150 V.

The developed toner image was transferred by corona discharge onto plain paper by a transfer device (not shown) and fixed by a heat roller fixing device at a surface humidity of 140°C.

The resulting recorded images are extremely clear, free from fog and edge effects, and have high density.
Subsequently, 50,000 sheets of recording paper were obtained in the same manner, and clear recorded images that remained stable from beginning to end were obtained.

On the other hand, if the developer transport carrier is not sprayed with Ni and has a smooth surface, the layer thickness regulating blade 7 is likely to be clogged with developer, etc. The amount of recording paper available was limited, and roughness was observed in the recorded images.

〔Effect of the invention〕

According to the developing device of the present invention, since the surface of the developer transporting carrier is formed in an uneven manner, a developer layer can be stably formed on the developer transporting carrier, and the developer layer can be separated by an oscillating electric field. Transfer control of toner particles has become more efficient, and high-quality images with excellent clarity can be reproduced without any problems even when using developers made of carrier particles or toner particles that have been converted into particles. be able to.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a recording device showing an example of the developing device of the present invention, and FIGS. 2 and 3 are perspective views showing an example of the structure of a developer transport carrier, respectively. DESCRIPTION OF SYMBOLS 1... Image forming body, 2... Plastic image side conveyance carrier, 3...
・Bias power supply, 4...protective resistor, 5...magnet,
6...Developer reservoir, 7...Layer thickness regulation blade, 8
・-Kuri 12 noda blade, 9... Stirring roller, 1
0: Toner supplementary thread combining roller, 11: Toner hopper. Patent Applicant Konishi Rokushapei Kogyo Co., Ltd. Agent Patent Attorney Haru Yasutaka Go ゛Figure 1 ? Figure 3

Claims (1)

[Scope of Claims] (1) A layer of developer in which magnetic carrier particles and toner particles are mixed is formed on the surface of a developer transporting carrier, and a latent image of an image forming member is formed from the developer layer under an oscillating electric field. A developing device for adhering toner particles, characterized in that the surface of the developer transporting carrier has an uneven surface. (2) The developing device according to claim 1, wherein the developer transport carrier surface is insulating or semi-insulating. (5) The developing device according to claim 1 or 2, wherein the developer layer is formed on the surface of the developer transporting carrier so as not to come into contact with the surface of the image forming body.