JPS5916938Y2 - developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic one-component developing device, and more specifically, to a trimmer blade for controlling the spikes of toner on a magnetic brush.

The developer used in conventional electrophotography is generally comprised of a mixture of two parts: iron powder or glass beads, called a carrier, and a resin and a colorant, called a toner.

By stirring and mixing the two, frictional electrification is generated, and by giving the toner a polarity opposite to the polarity of the charge held by the photosensitive material, the retoner is electrostatically attracted to the photosensitive material and visualized. It is something that

Furthermore, in electrophotography, which uses a transfer method commonly called PPC, a transfer material is brought into close contact with the toner image adsorbed on a sensitive material, and an electric field is applied from the back side of the transfer material to transfer the toner image to the transfer material. After the toner image is transferred onto the transfer material, the toner image is finally fixed onto the transfer material by means such as heating or pressure.

In this case, since the toner itself has charge, its transfer depends on the transfer electric field.

However, in recent years, development methods using the above-mentioned two-component toner have had problems, such as a decrease in developer life due to deterioration of the carrier, an increase in the complexity of the development device itself due to the need for a toner/carrier mixing ratio fluctuation correction device, and image quality due to toner charge fluctuations. In order to eliminate drawbacks such as instability, the toner itself contains magnetic powder and is treated with carbon black or the like to make it conductive to form a magnetic brush, and development is performed by electrostatic induction caused by charges on the sensitive material. is attracting attention.

That is, in this method, the electrostatic attraction caused by the developing electric field overcomes the magnetic attraction of the magnetic roll, so that the toner is transferred to the sensitive material side and the latent image is visualized.

In this case, the optimal means to create a high developing electric field is
The purpose is to bring the magnetic roll as close as possible to the static charge on the photosensitive material, that is, to the surface of the photosensitive material.

The method for supplying the developer to the sensitive material includes a method of rotating a sleeve, a method of rotating the magnetic roll, or a method of rotating both of the magnetic rolls configured as opposing magnetic poles in a non-magnetic sloop and its sleeve. There is.

Among these methods, in the method of rotating the sleeve or rotating both the sleeve and the magnetic roll, the toner conveyance capacity is extremely high, resulting in the phenomenon of oversupply of toner and the occurrence of white streaks during spike control. etc., and as a result, there is a drawback that unevenness tends to occur in the copied image.

Normally, a method is adopted in which the sleeve is fixed and an internal magnetic roll is rotated because it is easy to set up mechanically.

At this time, the internal magnetic roll has opposing magnetic poles arranged so that an alternating magnetic field is generated as a result of rotation, so that the toner attracted onto the sleeve is moved by the magnetic field.
It moves on the sleeve while rotating and reaches the developing section.

A plate called a trimmer blade is provided on the surface of the sleeve in order to adjust the amount of toner supplied on the snowball, control the formation of spikes, and make the adhesion uniform.

However, with this trimmer blade alone, a large amount of toner supplied accumulates in a lump on the front side of the trimmer blade, that is, on the opposite side from the developing section, and the toner solidifies in the lump, resulting in leakage to the developing side. At this point, the ear formation is no longer uniform.

This phenomenon cannot be improved no matter how much the precision of the trimmer blade tip is improved or the shape of the tip is modified.

The present inventors investigated the seed rod, found the cause of the above phenomenon, made the improvements described below, and completed the present invention.

That is, in the present invention, a trimmer blade is provided with a mesh-like diaphragm made of a magnetic material and has a rotating shaft, and the diaphragm is vibrated by an alternating magnetic field generated by the rotation of a magnetic roll to mix toner and crush accumulated toner. , the toner lumps that cannot be crushed are removed by a sieve effect, and a toner with uniform spikes is supplied to the developer, thereby improving the above-mentioned disadvantages and forming uniform spikes of developer, resulting in an even and good effect. It is designed to perform development.

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

FIG. 1 is a schematic cross-sectional view of a conventional developing machine.

The toner that comes out of the toner storage container 3 is sent to the trimmer blade 5.
However, toner lumps 6 are generated along the roll axis direction near the surface of the trimmer blade 5 on the storage container side.

In this toner mass, the toner rotates in the form of a ball.

FIG. 2 is a schematic cross-sectional view of the improved developing machine.

A plate-shaped magnetic plate is provided on the side surface of the trimmer blade opposite to the developing section.

In this developing machine, the magnetic plate vibrates as the magnetic roll rotates to crush toner lumps, so that the toner flows uniformly onto the sleeve.

However, due to the vibrating pressure of the plate-shaped magnetic plate, the toner is forced out of the trimmer blade, making it impossible to convey the appropriate amount of toner. Also, if too much toner accumulates, the plate becomes difficult to vibrate, causing the toner to be pushed out of the trimmer blade. It becomes a lump.

FIG. 3 is a schematic sectional view of the device of the present invention in which the diaphragm is replaced with a mesh-like one.

As the magnetic roll rotates, an alternating magnetic field causes a magnetic piece with a rotating shaft attached to the storage container side of the trimmer blade to vibrate, stirring the toner sent from the storage container in front of the trimmer blade, and toner particles. Put air in between,
Improves fluidity and feeds into the gap between the trimmer blade and sleeve.

In this device, the formation of toner lumps was prevented, uniform toner particles were supplied with good flow, and the above-mentioned drawbacks were eliminated.

If the mesh is too large, the effect of crushing the toner will be reduced, so it is necessary to select an appropriate mesh, preferably one with a mesh size of 60 to 100.

When installing a diaphragm on the trimmer blade, it may be fixed using screws, etc., but good results will be obtained if, for example, a rotating shaft is provided at the upper end of the diaphragm and the diaphragm is mounted so that it can swing as shown in Figure 4. is obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view of a conventional developing machine, Fig. 2 is a schematic sectional view of an improved developing machine, Fig. 3 is a schematic sectional view of a developing machine according to the present invention, and Fig. 4 is a schematic sectional view of the developing machine used in the present invention. 1 shows an example of a shaped diaphragm. Codes in the figure: 1... Fixed sleeve, 2...
・Magnetic roll; 3... Toner storage container; 4...
... Magnetic toner; 5 ... Trimmer blade; 6 ... Toner mass; 7 ... Rotating shaft; 8
...Magnetic piece; 9...Mesh-like magnetic plate.

Claims (1)

[Scope of utility model registration request] In a magnetic brush developing device having a fixed non-magnetic cylindrical sleeve, a magnetic roll rotatably provided inside the sleeve, and a trimmer blade provided close to the outer peripheral surface of the sleeve, the trimmer blade A magnetic brush developing device characterized in that a mesh-like magnetic plate having a rotating shaft at an upper end is arranged along a side surface opposite to the developing section so as to be swingable as the magnetic roll rotates.