JPS58220156A - Developing device - Google Patents

Abstract

PURPOSE:To enlarge a gap between a developer holding member and an image bearing member and to enable high speed development, by jumping a developer considerably apart from the former by an alternating electric field. CONSTITUTION:Electrodes 4... driven with alternating power supplies 5-7 are installed on the member 3 for feeding the developer 8, and the developer 8 is jumped by the alternating electric field due to the electrodes 4... considerably apart from the member 3 to develop an electrostatic latent image formed on the image bearing member 1. The gap between both members 1, 3 can be enlarged, mechanical precision can be alleviated, and yet, high speed good quality development can be achieved.

Description

Detailed Description of the Invention [Technical field to which the invention pertains] The present invention relates to a developing device that visualizes an electrostatic latent image of an electrophotographic device or an electrostatic recording device, and more specifically, it relates to a developing device that visualizes an electrostatic latent image on the surface of an electrophotographic device or an electrostatic recording device. The present invention relates to a one-component type developing device which directly feeds a developer to a charged area of a blank latent image to form a developed image without intervening a carrier.

[Prior art and its problems]

Conventionally, as an electrophotographic developing device, for example, U.S. Pat. No. 2,874,063, U.S. Pat.
．． A number of developing apparatuses are known based on the magnetic brush method, cascade method, powder cloud method, seven-arbrush method, etc. described in Japanese Patent No. 221,776, No. 2,902,974, and the like.

In the developing device of Otori et al., a two-component magnetic brush developing device and a cascade developing device, which mainly use toner and Yayaria as the developer, are generally put into practical use.

All of these developing devices are relatively stable and can easily produce images of excellent image quality.

However, despite these nine excellent features, they also have common drawbacks due to the use of two-component developers.

In other words, the toner acquires a triboelectric charge due to the mutual friction between the toner and the carrier, but after long-term use, the surface of the carrier becomes contaminated with the toner composition, making it impossible to obtain a sufficient charge. However, the surface of the photoreceptor may change due to long-term use and may deviate from the specified range.Furthermore, iron powder or glass beads whose surface has been acidified are used as a carrier material, but this may cause the surface of the photoreceptor to Examples of such problems include mechanical damage to the equipment.

In order to avoid such drawbacks, various developing devices have been proposed that are based on a developing method using a one-component developer consisting only of toner.

In particular, many developing devices based on the development method using what is generally called magnetic toner, which has magnetism as a toner, have been proposed, and U.S. Pat. No. 3,909,258 and U.S. Pat. A developing device based on the above has been put into practical use. 'I□ These developing methods using magnetic toner use magnetic toner with relatively low resistivity, so the developed image on the electrostatic latent image is electrostatically transferred to a support member such as plain paper. This is difficult, especially in a humid atmosphere, and sufficient transfer cannot be obtained.

Furthermore, the gap between the holder that holds the electrostatic latent image and the carrier that supplies the toner is small, and the precision of the device 75 is required to be extremely high. There are drawbacks such as the inability to obtain relat toner because of the

In order to eliminate such drawbacks, a developing device based on a developing method using a toner having a high specific resistance and not containing magnetic powder has recently been attracting particular attention.

For example, U.S. Patent No. 2,895,847;
2,012, etc., as well as Special Publication No. 41-9475, Special Publication No. 4
Various developing apparatuses have been proposed based on the touchdown method, impression method, and jumping method described in Japanese Patent Publication No. 5-2877 and Japanese Patent Publication No. 54-3624.

For example, JP-A-54-11742, JP-A-55-186
57, JP-A-55-118060, JP-A-55-533
71, JP-A-55-113069, etc.

These developing devices sufficiently overcome the above-mentioned drawbacks of developing devices based on magnetic toner.

In other words, the gap between the holder that holds the electrostatic latent image and the carrier that supplies the toner is extremely small, and for the device to be put to practical use, mechanical precision must be high, and high-speed development is difficult. , because the carrier is mechanically driven, vibrations and other effects are significant, and the developer is thin! # Various problems must be solved, such as the fact that it requires a great deal of effort to form.

[Purpose of the invention]

The purpose of the present invention was to take into consideration the drawbacks of the conventional apparatus described above, and it is possible to improve the conventional apparatus by providing a large gap between the holder and the carrier, which allows for gentle mechanical precision and high-speed development. The object of the present invention is to provide a new developing device that solves all the drawbacks of the above.

[Summary of the invention]

The developing device of the present invention includes a power source that generates alternating voltages with different phases from each other, a carrier for supplying a developing agent to an electrostatic latent image, and at least three or more electrodes on the surface or inside of the carrier. means for electrically connecting the power source and the electrode to generate an alternating electric field in the form of a traveling wave on the surface of the carrier;
means for placing a charged developer within the alternating electric field; and means for causing the developer to jump and move in the alternating electric field, and then being sent to a holder having an electrostatic latent image on its surface and developed on the electrostatic latent image. and means for forming an image.

The technical configuration of the present invention will be explained in more detail using FIG. 1.

In the figure, reference numeral 1 denotes a holder for holding an electrostatic latent image, which has an insulating layer or a photoreceptor layer on its surface, and an electrostatic latent image 2 that is positively charged is formed thereon.

Adjacent to the holding body 2, a supporting body 3 is placed.

At least three or more electrodes 4 are provided on the surface of the carrier 3.
are electrically connected as shown in the figure to power sources 5, 6, and 7 that generate alternating voltages at different positions, thereby generating an alternating electric field in the form of a traveling wave.

For example, the phases of the alternating voltages of power supplies 5-6 and 7 are each 120
The power supply 6 is adjusted to be 1200 ahead of the power supply 5, and the power supply 7 is 1200 ahead of the power supply 6.

That is, the voltage of each power supply is expressed as follows.

V5 =: 7m5ln W t V6 = vtnSIn(wt 2 rr / 3)
V? 1=Vm” (Wj 4 π/ 3) Kokote,
v5pV6Pv7 c power supply s-e and 7 alternating voltage vm
is the maximum value of 1 voltage of each power supply and is equal in this example.

When the charged developer 8 is placed in the alternating electric field of the traveling waveform on the surface of the book carrier 3, the developer 8 stays in the alternating electric field of the surface of the carrier 3 and jumps as it starts to be photographed. Move in the direction of the arrow in the figure. When the jumped developer 8 reaches the vicinity of the holder 1, the static electric field between the carrier 3 and the holder 1 (IJ 2) becomes larger than the alternating electric field on the surface of the carrier 3 described above. The developer 8 adheres to the electrostatic a-image 2 on the holder 1 to form a developed image.

In addition, since the developing device of the present invention uses an alternating electric field with a traveling waveform on the surface of the carrier 3, the electric field between the electrodes 4 on the surface of the carrier 3 is equal to the electric field generated between the carrier 3 and the holder 1. It is necessary to make it larger than .

This is because, if the electric field generated between the carrier 3 and the holder 1 is larger than the electric field between the electrodes 4, only reciprocating motion, that is, imaging, is caused between the carrier 3 and the holder 1, and the developer 8 is Not only is there no movement, but inefficient development is performed in which the developer is once developed and then brought back again.

Further, there are disadvantages such as destruction of the photoreceptor due to discharge and a reduction in the gap between the carrier 3 and the holder 1.

〔Effect of the invention〕

According to the current iron device of the present invention, the large alternating electric field on the surface of the carrier can cause the 031 cleaning agent to jump over a long distance, so it is one step to increase the gap between the carrier and the holder. It became.

11 ■ Effect: There is no need to mechanically move the carrier to move the phenolic agent.

Therefore, there is no need for mechanical movement of the carrier or efforts to maintain a constant gap between the carrier and the support.

(2) Since the developer does not cause reciprocating movement between the holder and the carrier, efficient development can be achieved with zero labor.

■There is no capri because only the charged developer adheres to the electrostatic latent image trap on the holder.

■Deep images can be obtained because the developer adheres to the electrostatic latent image in the form of a cloud of dispersed primary particles.

You can obtain sharp images with good gradation, good fine line reproduction, and edge effects.

■Do not destroy the holding body due to electrical discharge.

■Since non-contact development is possible, there is no mechanical damage to the holder.Developer does not aggregate on the surface of the holder.

Since post-development can be performed without disturbing the developed image adhering to the electrostatic latent image, it can be easily introduced into a color copying machine.

[Examples of actual rights to inventions]

Hereinafter, the present invention will be explained with reference to an illustrated embodiment.

FIG. 2 is a front view showing an embodiment of the present invention, showing a schematic configuration thereof. Reference numeral 9 denotes a cylindrical holder for holding an electrostatic latent image, and has an insulating layer or a photoreceptor layer on its surface.

That is, a photoreceptor drum is used in which a selenium-tellurium (Se-!re) alloy photoreceptor is deposited on the surface of an aluminum drum having a diameter of 78φ and a thickness of 21μ11.

A positively charged electrostatic latent image 10 is formed on the surface of this holder 90. In this example, the electrostatic trench 10 is formed by uniformly charging the surface of the holder 9 with a well-known corona charger or roller charger, and then performing imagewise exposure.

Furthermore, in addition to this, a pattern depending on the image to be formed may be formed using a cathode ray tube or a laser beam, or a dot pattern of electrostatic charge may be formed using a needle electrode light emitting diode or the like.

The above-mentioned holder 9 has a circumferential speed of 80 mrIL in the direction of the arrow shown in the figure.
/, me, and the surface potential of the electrostatic latent image 100 is set in the range of +300 to +800V.

Note that the aluminum drum of the holder 9 is grounded. A carrier 11 made of an insulating material and curved along the curvature of the holder 9 is provided at a position facing the holder 9. The gap between the holder 9 and the carrier 11 is 0.8 to 1 Q
The length is selected within a range of approximately mm, and is set to 2 mm as an example. Electrodes 12 with a diameter of 0.3 mm are provided on the carrier 11 at the positions shown in the figure, with Q, 5 mttr between each electrode 12, and alternating voltages with different button phases are generated in each electrode 12. Power supply 13 #14 and 15
The electric button is held as shown.

As an example, there are 13 power sources with different phases of 120 degrees each.
and 15 are used to generate a traveling waveform alternating electric field between the electrodes 12.

As the waveforms of the power supplies 13, 14, and 15, all AC waveforms such as rectangular waves, sine waves, and triangular waves can be used, but a sine wave is used as an example.

In addition, the frequency needs to be selected to a desired value depending on the circumferential speed of the holding body 9. For example, the frequency of IJG (z is used. If the circumferential speed of the holding body 9 is high, 10, KHz
~I IG (on the contrary, in the case of l KHz %
Can be selected within the range of 0.3 Kklz. The voltage of the power supplies 13114 and 15 is an important factor that affects the magnitude of the alternating electric field between each electrode 12, and in this example, the voltage is 2000Vp-
All power supplies are set to p, and the maximum alternating electric field between each electrode 12 is approximately 8000 V/home. At this time, an alternating electric field is also generated between the supporting body 11 and the holding body 9, but at most,
It is about 1500V/home. When a negatively charged developer 16 (for example, insulating toner particles are used) is fed onto the carrier 11 by a desired means, a progression occurs between the electrodes 12 of the carrier 11. The electrostatic latent image 10 on the surface of the holder 9 is attached to form a developed image while forcibly jumping and moving in the direction of the arrow in the waveform alternating electric field.

In addition, since the developing device of the present invention can freely adjust the surface of the supporting member 11 relative to the holder 9, it is possible to perform development even at a high speed of B 00 myn/sec as the circumferential speed of the holder 19. be. In this case, for example, about 1/4 circumferential surface of the drum of the holder 9 may be used.

The developer 16 used in the present invention can be any charged developer (toner particles), regardless of polarity.

As toner particles, styrene I acrylic t epoxy t
Carbon black in resin such as polyamide-polyester p polyethylene t polypropylene t maleic acid-rosin ester or a copolymer thereof? Ferrai) = All common materials containing inorganic or organic pigments, dyes, etc. in desired proportions can be used.

Further, as the insulating material of the supporting woodwork 1, organic materials such as Teflon, nylon, p-Delrin, ceramic materials such as alumina, zircon, and beryllia are used.

For the electrode 12, a wire material such as tungsten copper p-aluminum is used.

According to the developing device of the present invention, the developer 16 is exposed to a large alternating electric field on the surface of the carrier 11.
Since it is possible to jump over long distances, it has become possible to increase the gap between the carrier and the holding body in the range of 8 mm to 10 m1.

・b There is no need to mechanically move the carrier to move the developer.

Therefore, mechanical vibration of the carrier is almost eliminated, and there is no need to maintain a constant gap between the carrier and the holder, making machine setting extremely easy.

Since the Cie agent does not cause reciprocating movement between the holder 9 and the carrier 11, efficient development is possible.

Only the developer 16 charged with the electrostatic latent image 1 on the holder 9
0, so there is very little fog.

Since the developer 16 adheres to the electrostatic latent image 10 in the form of a cloud of dispersed primary particles, a dense image can be obtained with good gradation. Furthermore, fine line reproduction is good and a sharp image with an effective edge effect can be obtained, so the clarity is excellent. Do not destroy the holding body by electric discharge.

e Since non-contact development is possible, there is no mechanical damage to the holder, and developer 16
Since post-development can be performed without disturbing the developed image adhered to the surface of the carrier 11, it is easy to introduce the color to the copying surface.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram illustrating the outline of the developing device of the present invention, and FIG.
The figure is a sectional view of the main part of the developing device of the present invention. (1) (9)...Holding body, (3) (1υ...Supporting body, f4) if...'4L rain. Agent: Patent attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2

Claims (1)

[Claims] A power source that generates alternating voltages with different phases from each other, a carrier that supplies developer to the electrostatic latent image, and at least three or more electrodes on the surface or inside the carrier, the power source and the electrodes. means for electrically connecting the two to produce an alternating electric field in the form of a traveling wave on the surface of the carrier; means for placing a charged developer within the alternating electric field; and means for moving the carrier to a holder having an electrostatic latent image on its surface and forming a developed image on the electrostatic latent image.