JP2867897B2 - Electrophotographic printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic printing apparatus, and more particularly, to an electrophotographic printing apparatus provided in a printer, a facsimile, a copying machine or the like using an electrophotographic process.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional example. The conventional example of the electrophotographic printing apparatus in FIG. 5 includes a photosensitive drum 51,
A charger 52 for uniformly charging static electricity for forming an electrostatic latent image on the photosensitive drum 51; a developing roller 53 for developing the electrostatic latent image on the photosensitive drum 51;
3 is provided with a toner layer regulating blade 54 for uniformly regulating the layer thickness of the toner layer attached to the outer peripheral surface. Reference numeral 56 denotes a protection plate for the charger 52 .

In the conventional example shown in FIG. 5,
At the time of regulating the thickness of the toner layer on the upstream side of the developing position with respect to the photosensitive drum 51, the floating toner scatters in the apparatus by using the developing roller 53 of FIG. In this case, if the floating toner adheres to the electrode portion 52A of the charger 52, charging failure occurs, and the printing quality may deteriorate.

In order to prevent this, generally, the charger 5
2 and a protection plate 56 is attached to the electrode portion 52A of the charger 52.
As a countermeasure, a method of making it difficult for the floating toner scattered to adhere to the surface has been conventionally adopted.

[0005]

However, in the above-mentioned conventional example, the floating toner scattered from the developing roller 53 in FIG. 5 only makes it difficult to adhere to the electrode portion 52A of the charger 52. Generation and scattering of the toner are continuously occurring, and at this point, the situation where the floating toner is scattered in the apparatus still exists. For this reason, when the amount of the floating toner is large, the toner adheres to the photosensitive drum 51, and the printing quality is deteriorated due to the toner, thereby causing a problem that the reliability of the entire apparatus is impaired.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to improve the disadvantages of the prior art, and to effectively prevent the generated floating toner from scattering into the apparatus. It is an object of the present invention to provide an electrophotographic printing apparatus in which the degree of charging failure on a drum and the amount of floating toner adhering on the photosensitive drum are effectively suppressed to improve print quality.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a photosensitive drum and a charge for uniformly charging static electricity for forming an electrostatic latent image on the photosensitive drum are provided. A developing roller for developing the electrostatic latent image on the photosensitive drum, and a toner layer regulating blade for uniformly regulating the layer thickness of the toner layer attached to the outer peripheral surface of the developing roller . . Between the developing roller and the charger,
Equipped with a developing roller shielding mechanism close to the
You.

Further, this developing roller shielding mechanism is described above.
Shielding plate arranged along the developing roller
A predetermined distance between the surface of the shielding plate facing the developing roller
It comprises a plurality of baffles protruding from each other .

[0009] The protruding length of each baffle plate is described above.
Longer the further downstream in the direction of rotation of the developing roller
Configuration .

[0010] According to the second aspect of the present invention, the above-mentioned claim is provided.
1. The electrophotographic printing apparatus according to item 1, wherein a plurality of baffle plates
Connect the end face of the protruding end toward the developing roller
In this case, the position is set so as to be located on a concentric circle close to the center line.

Thus, the above-mentioned object is achieved.

[0012]

[Operation] When the entire apparatus is set in the operating state, the operation of supplying the toner to the developing roller 3 is started at the same time. In this case, a toner layer thickness regulating blade 4 is pressed against the developing roller 3, and the toner layer thickness is regulated by the toner layer thickness regulating blade 4. The floating toner is generated during the operation of regulating the layer thickness by the toner layer thickness regulating blade 4 and at the time of contact between the developing roller 3 and the photosensitive drum 1, that is, at the time of development. For this reason, the generation of floating toner always accompanies its structure.

On the other hand, the developing roller shielding mechanism 10
This effectively prevents the floating toner from scattering toward the charger 2 due to the rotation of the developing roller 3 by blocking the space. Therefore, the electrode 2A of the charger 2
Of the photosensitive drum 1 is reduced, and defective charging of the photosensitive drum 1 is reduced. Thereby, the print quality can be improved over a long period of time.

[0014]

BRIEF DESCRIPTION based Kazumi施例of the present invention in FIGS.

First, FIG. 1 shows the basic configuration of the background of the present invention .
A simple configuration is shown . In FIG. 1, reference numeral 1 denotes a photosensitive drum, reference numeral 2 denotes a charger for uniformly charging the electrostatic electrostatic latent image formed on the photosensitive drum 1. The charger 2 is provided with a protection plate 2B, which effectively prevents the floating toner from adhering to the electrode 2A in the charger 2.
The symbol K indicates an exposure light beam. A predetermined electrostatic latent image is formed on the photosensitive drum 1 by the exposure light beam K.

Reference numeral 3 denotes a developing roller. The developing roller 3 has a function of developing the electrostatic latent image on the photosensitive drum 1 with toner. The developing roller 3 is provided with a toner layer regulating blade 4 for uniformly regulating the thickness of the toner layer attached to the outer peripheral surface of the developing roller 3. Further, the developing roller 3 is provided with a toner storage section 6 for supplying a predetermined amount of toner to the developing roller 3 via the toner supply roller 5.

Then, the above-described charger 2 of the developing roller 3
On the side, a developing roller shielding mechanism 10 on the partition plate is provided. The developing roller shielding mechanism 10 has a leading end mounted close to the photosensitive drum 1 described above, and has the other end fixedly mounted on the storage case body 6A of the toner storing section 6 together with the toner layer regulating blade 4 described above. The developing roller shielding mechanism 10 is formed of a resin-based material such as ABS or PC, or a metal-based material such as SUS, Fe, or Al. In this case, the developing roller shielding mechanism 10
Is set such that the position of the approach surface closest to the developing roller 3 is within 3 [mm].

[0018] Other configurations are the same as those of the conventional example described above (see FIG. 5).

Next, the operation of the above-described basic configuration will be described.

First, when the entire apparatus is set to the operating state,
The operation of supplying the toner to the developing roller 3 is also started at the same time. In this case, a toner layer thickness regulating blade 4 is pressed against the developing roller 3, and the thickness of the toner layer supplied from the toner supply roller 5 is regulated by the toner layer thickness regulating blade 4. The above-mentioned floating toner is generated during the operation of regulating the layer thickness by the toner layer thickness regulating blade 4. The developing roller 3 and the photosensitive drum 1
, That is, floating toner is also generated during development. For this reason, the generation of floating toner always accompanies its structure.

The developing roller shielding mechanism 10 effectively prevents the floating toner from scattering toward the charger 2 due to the rotation of the developing roller 3 by shielding the space. For this reason, dirt on the electrode 2A of the charger 2 is reduced, and charging failure on the photosensitive drum 1 is reduced. Thereby, the print quality can be improved.

FIG. 2 shows a modification of the developing roller shielding mechanism 10. As shown in FIG.

The current image roller shielding mechanism are shown in FIG. 2 11
Is formed of a plate- like member, and the developing roller 3
Is formed so as to be entirely curved so that a surface facing the developing roller 3 is concentric with the developing roller 3. In this case, the developing roller shielding mechanism 11
The distance between the developing roller 3 and the developing roller 3 is set within 3 [mm]. Other configurations are the same as the case of FIG. 1 described above.

In this way, the floating toner once discharged from the developing roller 3 is gradually suppressed from scattering in a narrow space between the developing roller 3 and the developing roller shielding mechanism 11 and is again sucked toward the developing roller 3. You. Therefore, there is an advantage that the amount of floating toner scattered from the developing roller 3 is greatly reduced.

FIGS. 3 and 4 show another example of the developing roller shielding mechanism.
A modified example will be described.

[0026] FIG. 3 to the current image roller shielding mechanism 1 2 are shown in Figure 4, the blocking plate 12A disposed opposite to the developing roller 3 described above, the developing roller 3 described above in the blocking plate 12A It is provided with a plurality of baffle plates 12B protruding from the opposing surface at predetermined intervals. FIG. 4 shows an example of the baffle plate 12B.

That is, the developing roller shown in FIGS.
The shielding mechanism 12 moves along the developing roller 3 as shown in the drawing.
The disposed shielding plate 12A and the shielding plate 1
2A at a predetermined distance from the surface facing the developing roller 3 described above.
And a plurality of baffle plates 12B projecting therefrom.
Have been. And the protruding length of each baffle plate 12B is
As shown in the figure, on the downstream side in the rotation direction of the developing roller 3 described above,
The longer it is located, the longer it is set. In this case, each baffle
.., 12B, 12B,...
The end surface of the protruding end toward the image roller is the developing roller 3 described above.
Is set so as to be located on a concentric circle close to.
That is, each of the baffle plates 12B, 12B,... Is formed so that the end surface on the side of the developing roller 3 is located on a surface that is entirely curved so as to be concentric with the developing roller 3. The distance between the end face of each baffle 12B and the development roller 3, similar to the case of FIG. 2 described above 3 mm.
The length of each baffle plate 12B is set to 1 mm or more. Other configurations are the same data as in the Figure 2 described above.

Also in this case, FIGS.
In addition to the above-described function, the floating toner is shielded stepwise at a plurality of locations by the action of the baffle plate 12B and is also absorbed by the baffle plate 12B, so that the scattering of the floating toner is further suppressed. Decrease.

[0029]

The present invention is constructed and functions as described above. According to this, the scattering of the toner from the developing roller can be effectively suppressed by the operation of the developing roller shielding mechanism. Adhesion of floating toner to the electrode portion can be almost completely prevented, and therefore, stable printing quality can be ensured for a long period of time, and therefore, an unprecedented excellent electronic device that can improve the reliability of the entire apparatus. A photographic printing device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a second embodiment of the present invention.

FIG. 3 is a schematic sectional view showing a third embodiment of the present invention.

FIG. 4 is a partially omitted perspective view showing a developing roller shielding mechanism disclosed in FIG. 3;

FIG. 5 is a schematic sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Charger 3 Developing roller 4 Toner layer regulating blade 10, 11, 12 Developing roller shielding mechanism 12A Shielding plate 12B Baffle plate

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 15/08-15/095 G03G 21/00

Claims (2)

(57) [Claims] 1. A photosensitive drum, and a charger for uniformly charging static electricity for forming an electrostatic latent image on the photosensitive drum,
Electrophotographic printing comprising: a developing roller for developing an electrostatic latent image on the photosensitive drum; and a toner layer regulating blade for uniformly regulating a layer thickness of a toner layer attached to an outer peripheral surface of the developing roller. in the device, between the charging device and the developing roller, the developing roller
Close equipped with the developing roller shielding mechanism, the developing roller shielding mechanism, distribution along the developing roller
A shielding plate provided and the developing of the shielding plate
A plurality of protrusions protruding from the surface facing the rollers
And the length of projection of each of the baffles is determined by the rotation direction of the developing roller.
An electrophotographic printing apparatus characterized in that it is set longer as it is located downstream of the printer. 2. A plurality of baffle plates facing the developing roller.
The end face of the protruding end is concentric with the developing roller.
2. The apparatus according to claim 1 , wherein the setting is made so as to be located above.
An electrophotographic printing apparatus as described in the above.