JPS62177576A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the generation of blocking by forming a vibration part having a piezo-electric element for applying vibration to a doctor member and a means for impressing an alternate voltage to the piezo-electric element. CONSTITUTION:When a magnetic field generating member 9 is rotated in an arrow X direction, magnetic toner 3 absorbed to the surface of a sleeve 6 is carried in an arrow Y direction, regulated by the doctor member 5 so as to be set up to a prescribed thickness, and then carried to a developing gap D. When a switch 13 is turned on, an AC voltage is impressed to the piezo-electric element 11 and bent because the element 11 is extended in the same direction as a polarizing direction when the voltage in the same direction is impressed, or contracted when the reverse voltage impressed. Thereby, the doctor member 5 is vibrated in its thickness direction on the basis of the extension/contraction of the element 11. Consequently, the vibration is transmitted to the magnetic toner arranged near the doctor member 5 in a toner case 4, so that the toner can be prevented from blocking and a uniform toner layer can be formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a development method for visualizing an electrostatic latent image using a magnetic developer in an electrophotographic device, an electrostatic recording device, or an electrostatic printing device. Regarding equipment.

[Conventional technology]

In this type of image forming apparatus, an electrostatic latent image formed on an image carrier such as a photoconductor layer or a dielectric layer is developed using a magnetic developer, and the resulting developed image is transferred onto plain paper, etc. It is common to obtain the final image by transferring it onto a member and then fixing it. Examples of the magnetic developer used here include a -component magnetic 1-ner, a developer prepared by mixing a magnetic carrier such as iron powder or ferrite powder, and a non-magnetic or magnetic toner.

The magnetic brush method is generally used as a developing method, but in order to prevent blurring, there is a jumping developing method that uses insulating magnetic toner to develop without contacting the image carrier.
For example, see Japanese Patent Application Laid-open Nos. 55-18656 to 18658).

When developing an electrostatic latent image using a magnetic developer, it has been proposed to provide a magnetic material near the tip of a doctor member in order to regulate the thickness of the developer conveyed on the developing roll. (See FIG. 9 of JP-A-51-16926). This magnetic body is provided to agitate the developer and prevent blocking when regulating the developer.

Further, in the jumping development method, a doctor blade made of a magnetic material (iron) is used to form a uniform thin toner layer on the development roll. That is, the magnetic blade forms opposing magnetic poles with the magnetic pole of the developing roll, forces the toner to stand up between the doctor caps, and by giving forced movement to the toner, the doctor gap of 175
It forms a single layer of toner with a thickness of approximately (See, for example, the Journal of Electrophotography, Vol. 20, No. 1, pages 8 to 17) [Problems to be solved by the invention] In order to achieve the purpose with the doctor blade made of the above-mentioned magnetic material, it is necessary to The magnetic poles of should be stationary. In other words, in order to convey the developer on the developing roll, it is only necessary to rotate the sleeve and the magnetic field generating member inside it relative to each other, but when using a magnetic blade, it is necessary to rotate only the sleeve. . However, depending on the type of developer, it may be necessary to rotate the magnetic field generating member or the sleeve together with the magnetic field generating member. However, when a magnetic blade is used, there is a problem in that only the sleeve rotation method can be applied. Additionally, non-magnetic blades have the disadvantage that the thin toner regulating gap is easily clogged with paper particles, especially when the sleeve rotates.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a developing device that can apply stirring motion to developer in various developer transport systems. Furthermore, it is an object of the present invention to provide a developing device that can stably regulate the amount of developer without clogging the narrow gap with the sleeve with paper dust, even if it is a non-magnetic blade type.

[Means for solving problems]

The developing device of the present invention includes a developing roll having a non-magnetic sleeve provided facing an image carrier, a magnetic field generating member provided inside the non-magnetic sleeve, a container containing a magnetic developer, and a container placed on the developing roll. A developing device is provided with a doctor member for regulating the thickness of a magnetic developer being conveyed, a vibrating member having a piezoelectric element for imparting vibration to the doctor member, and an alternating voltage applied to the piezoelectric element. It is characterized by having means for applying.

〔Example〕

The details of the present invention will be explained below with reference to the accompanying drawings.

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

The developing device includes a developing roll 2 provided facing a photoreceptor l that holds an electrostatic latent image (not shown) on its surface, a toner container 4 containing magnetic toner 3, and a toner container 4 attached to the developing roller 2. The doctor member 5 has a doctor member 5. The developing roll 2 includes a sleeve 6 made of a non-magnetic material such as an aluminum alloy or austenitic stainless steel, and is provided inside the sleeve.
It has a magnetic field generating member 9 formed by fixing a permanent magnet 7 having a plurality of magnetic poles to a shaft 8. 10 is a vibrating member provided on the surface of the doctor member 5.

FIG. 2 is an enlarged view of the main part of FIG. 1. The vibrating member 10 is
It has a piezoelectric element 11 having a width approximately corresponding to the effective development width and electrodes 12° and 12' fixed to the surface of the piezoelectric element.

Electrodes 12 and 12' are connected via a switch 13 to an alternating current voltage source 14. The piezoelectric element 11 is a piezoelectric bimorph formed by bonding together two piezoelectric ceramics that have been polarized in the thickness direction after firing. Two arrows in the figure indicate the polarization direction of each ceramic. Although the figure shows a series type piezoelectric bimorph, a parallel type piezoelectric bimorph may also be used. Piezoelectric ceramics include, for example, zircon lead titanate (
PZT) ceramics can be used, but other materials such as lead titanate (PbTiOi) ceramics, which have a smaller electromechanical coupling coefficient for vibration in the width direction than electromechanical coupling for vibrations in the thickness direction, can also be used.

The operation of the above-mentioned developing device will be explained as follows. When the magnetic field generating member 9 is rotated in the direction shown by the arrow X in FIG.
is conveyed in the direction shown by arrow Y, regulated to a predetermined thickness by doctor member 5, and then conveyed toward development gap D.

When the switch 13 shown in FIG. 2 is turned on here, an alternating current voltage is applied to the piezoelectric element 11. When a voltage is applied in the same direction as the polarization direction, the piezoelectric element stretches in that direction, and when a voltage is applied in the opposite direction, it contracts and bends.

Therefore, the doctor member 5 vibrates in its thickness direction due to the expansion and contraction of the piezoelectric element. In this way, vibrations are applied to the magnetic toner near the doctor member 5 in the toner container 4, so that blocking of the toner can be prevented and a uniform layer of toner can be formed.

The present invention is not limited to the above-mentioned embodiments, but can also have the following configuration. The sleeve 6 may be stationary, but if the toner needs to be conveyed at high speed (for example, as in Japanese Patent Laid-Open No. 53-31136), the sleeve 6 may be rotated in the opposite direction to the magnetic field generating member 9. Further, when the toner is conveyed at a low speed (for example, as disclosed in Japanese Patent Application Laid-Open No. 55-126266), the sleeve 6 may be rotated in the same direction as the magnetic field generating member 9. The present invention can also be applied to a case where the doctor member 5 is made of a magnetic material and only the sleeve 6 is rotated. According to this example, the effect of the magnetic material blade and the vibration caused by the piezoelectric element are superimposed, resulting in a large effect. is obtained. Furthermore, it goes without saying that non-magnetic blades can also be applied. Further, in order to further facilitate the vibration of the doctor member, the vicinity of the tip thereof may be made thinner than the other portions, as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, since the vibrating member is fixed to the doctor member, the toner transport method is not limited, and good development can be performed.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a developing device according to an embodiment of the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a main part of a developing device according to another embodiment of the present invention. It is an enlarged view. 1: Photoreceptor, 2: Developing roll, 3: Magnetic toner, 4: Toner container, 5: Doctor member, 6: Sleeve, 9: Magnetic field generating member, 10: Vibrating member, 11: Piezoelectric element, 12.1
2': Electrode.

Claims (2)

[Claims] (1) A developing roll having a non-magnetic sleeve provided facing the image carrier, a magnetic field generating member provided inside the non-magnetic sleeve, a container containing a magnetic developer, and conveyance over the developing roll. A developing device having a doctor member for regulating the thickness of the magnetic developer, which is provided with a vibrating section having a piezoelectric element for imparting vibration to the doctor member, and further comprising means for applying an alternating voltage to the piezoelectric element. A developing device characterized by: (2) The developing device according to claim 1, wherein the piezoelectric element is formed from a zircon-lead titanate ceramic or a lead titanate ceramic.