JP2000347505A - Developing device and image forming device attached thereto - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of recovered toner by having a toner scraping means to scrape the recovered toner stuck to a toner supply roller from a developing roller. SOLUTION: The developing roller 3c of a developing device 3 in which toner 3a is stored abuts on a toner image carrier 1. The recovered toner 3a2 still stuck to the developing roller 3c without being transferred to the toner image carrier 1 is moved to the toner supply roller 3b by the rotation of the developing roller 3c. Then, it is fed to a toner scraping blade 3f by the rotation of the toner supply roller 3b, and is scraped off from the toner supply roller 3b then and is mixed with new toner 3a1. It is desirable that the toner scraping blade 3f is an elastic plate-like member, a rigid plate-like member or a brush. Thus, a phenomenon to repeat the movement of the recovered toner 3a2 between the toner supply roller 3b and the developing roller 3c is evaded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a developing device attached to an image forming apparatus using a one-component developing system and an image forming device equipped with the developing device.

[0002]

2. Description of the Related Art In recent years, toner-type image forming apparatuses capable of forming clear images with excellent resolution, such as laser printers, have become widespread. Among such toner-type image forming apparatuses, an image forming apparatus using a one-component developing method is very suitable for promoting high image quality because of its configuration.

Hereinafter, a conventional image forming apparatus using such a one-component developing system will be described.

FIG. 3 is an explanatory diagram showing a developing device attached to a conventional image forming apparatus.

[0005] Around the toner image carrier, the surface of which is coated with an organic photoconductive material layer, there are provided a charge removing means, a cleaning means, a charging means, a developing device, and an exposure means. Further, a paper transport belt is provided in contact with the toner image carrier. Further, a transfer roller for transferring the toner image on the toner image carrier to the printing paper conveyed on the paper conveying belt is arranged.

Here, as shown in detail in FIG. 3, the developing device 3 has a housing for accommodating the toner 3a. In this housing, a developing roller 3c for forming a toner image by attaching toner 3a to the electrostatic latent image formed on the toner image carrier 1, and a toner 3a
Is supplied rotatably. Further, there is provided a thinning blade 3d which is brought into pressure contact with the developing roller 3c and makes the toner 3a supplied to the outer peripheral surface of the developing roller 3c a predetermined thickness.

According to such an image forming apparatus, the laser is turned on / off by the information of the image sent from the host computer, and the electrostatic latent image is placed on the toner image carrier 1 uniformly charged by the charging means. An image is formed.

On the other hand, in the developing device 3, the toner 3a in the housing is supplied to the developing roller 3c by the toner supply roller 3b. Then, the toner 3a supplied to the developing roller 3c is regulated to a predetermined layer thickness by the thinning blade 3d, whereby a uniform toner layer is formed on the developing roller 3c.

When the toner adheres to the electrostatic latent image on the toner image carrier 1 from the developing roller 3c, a toner image is formed.

[0010]

However, in the conventional image forming apparatus described above, the toner collected without being transferred from the developing roller 3c to the toner image carrier 1, that is, the collected toner 3a ₂ (see FIG. 3) The toner (indicated by Δ) repeatedly moves between the toner supply roller 3b and the developing roller 3c until it is used for image formation. And since friction and high pressure application are repeated in the process of such movement,
It gradually deteriorates.

In particular, when printing with small toner consumption is repeated, the toner supply roller 3b and the developing roller 3c
Since the ratio of the recovered toner 3a2 which repeats the movement between the steps 3 and ₄ increases, the deterioration of the image quality due to the deterioration of the toner 3a becomes remarkable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device capable of preventing deterioration of collected toner and an image forming apparatus to which the developing device is attached.

[0013]

To solve this problem, a developing device according to the present invention comprises a developing roller for forming a toner image by attaching toner to a toner image carrier having an electrostatic latent image formed thereon. And a toner supply roller for supplying toner to the developing roller, and a toner scraping unit for scraping the collected toner attached to the toner supply roller from the developing roller.

This makes it possible to prevent the collected toner from deteriorating.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a developing roller for forming a toner image by attaching toner to a toner image carrier having an electrostatic latent image formed thereon, And a toner scraping means for scraping the collected toner attached to the toner supply roller from the developing roller, and has a function of preventing the collected toner from being deteriorated. .

According to a second aspect of the present invention, in the first aspect, the toner scraping means is an elastic plate-like member, a rigid plate-like member, or a brush pressed against the toner supply roller. This is a developing device, and has an effect that deterioration of collected toner can be prevented.

According to a third aspect of the present invention, there is provided an image forming apparatus to which the developing device according to the first or second aspect is attached, which has an effect that deterioration of collected toner can be prevented. .

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

FIG. 1 is an explanatory view showing an image forming apparatus to which a developing device according to an embodiment of the present invention is attached, and FIG. 2 is an explanatory view showing the developing device in the image forming apparatus of FIG. 1 in detail.

As shown in FIG. 1, the image forming apparatus of the present embodiment is provided with a toner image carrier 1 whose surface is coated with a layer of an organic photoconductive material. The toner image carrier 1 is rotated in the direction of arrow A by a drive motor (not shown).

A developing device 3 containing a toner 3a of negative polarity is provided corresponding to the toner image carrier 1.

As shown in detail in FIG. 2, the developing device 3
It has a housing in which the toner 3a is stored. In this housing, a developing roller 3c for attaching a toner 3a to an electrostatic latent image formed on the toner image carrier 1 to form a toner image, and a toner supply roller 3b for supplying the toner 3a to the developing roller 3c rotate. Mounted freely.

Further, there is provided a thinning blade 3d which is brought into pressure contact with the developing roller 3c and makes the toner 3a supplied to the outer peripheral surface of the developing roller 3c a predetermined thickness.

Further, the toner supply roller 3b is pressed against the toner supply roller 3b.
Is not transferred from the developing roller 3c to the toner image carrier 1.
Toner collected on the toner supply roller 3b
-3a _Two(Toner indicated by △ in FIG. 2)
A scraping blade (toner scraping means) 3f is provided.
ing.

It should be noted, take off the collected toner 3a ₂ adhering to the toner supply roller 3b, a toner scraping blade 3f as in this embodiment, i.e. may not be elastic plate-like member. That is, it is possible to use various members such as the rigid plate-shaped member or a brush, capable of scraping the collected toner 3a _2.

Although the present embodiment shows a single-color image forming apparatus, the present invention can be applied to a multi-color image forming apparatus.

In FIG. 1, a charging means 2, a cleaning means 5, and a charge removing means 4 are arranged around a toner image carrier 1, and an upper portion of the toner image carrier 1 is exposed to laser light. Means 6 are provided.

As a result, the portion of the toner image carrier 1 that has passed through the charging means 2 is uniformly charged by corona discharge by the charging means 2, and the toner image carrier is irradiated with laser light of image data emitted from the exposure means 6. 1 is partially lost, and an electrostatic latent image corresponding to a specific component among predetermined color components is formed on the toner image carrier 1. Then, when the toner 3a is pressed against the portion where the electrostatic latent image is formed by the developing roller 3c, the visible toner images 3e appear one after another on the toner image carrier 1.

The exposure means 6 includes an LED or LC.
D or the like can also be used.

A paper transport path on which the printing paper 7 travels is formed in contact with the outer peripheral surface of the toner image carrier 1. Then, a transfer roller 9 for transferring the toner image 2 e on the toner image carrier 1 to the printing paper 7 is disposed in pressure contact with the toner image carrier 1 with the sheet transport path interposed therebetween.

A paper cassette 11 for storing the printing paper 7 is provided below the image forming apparatus. Then, the printing paper 7 is sent out one by one from the paper cassette 11 to the paper transport path by the paper feed roller 8.

In order to fix the toner image 3e transferred to the printing paper 7, a fixing means 10 including a heat roller having a heat source therein and a pressure roller is disposed. Then, the composite image transferred by the pressure and the heat is fixed to the printing paper 7 by the pinching rotation of the heat roller and the pressure roller when passing through the fixing unit 10, and a color image is formed.

The operation of the image forming apparatus and the developing device thus configured will be described below.

In FIG. 1, first, the surface of the toner image carrier 1 is uniformly charged by corona discharge in the charging means 2 connected to a high voltage power supply.

Next, the toner image carrier 1 is rotated in the direction of arrow A by a driving device (not shown), and the surface of the uniformly charged toner image carrier 1 is irradiated with laser light from the exposure means 6. Then, the irradiated portion on the toner image carrier 1 loses the charge, and is exposed in a pattern corresponding to the image signal to form an electrostatic latent image.

On the other hand, the developing roller 3c of the developing device 3 in which the toner 3a contributing to the development is stored is in contact with the toner image carrier 1.

A bias voltage is applied to the developing roller 3c, and the toner is applied only to the portion of the toner image carrier 1 irradiated with the laser beam by the electric field acting between the surface of the developing roller 3c and the toner image carrier 1. 3a is transferred, and a visible toner image 3e appears on the toner image carrier 1.

On the other hand, the printing paper 7 is taken out of the paper cassette 11 by the paper feed roller 8, and is conveyed on the paper conveyance path.

Here, the toner image 3 formed on the toner image carrier 1 is
e is transferred onto the printing paper 7 by the transfer roller 9. As a result, the toner image 3e is transferred onto the printing paper 7.

The printing paper 7 on which the toner image 3e has been transferred in this manner is sent to the fixing means 10. Then, the toner image 3e is generated by heat and the sandwiching force between the heat roller and the pressure roller.
Is fixed on the printing paper 7. Finally, the printing paper 7 that has passed through the fixing unit 10 is discharged to a paper discharge tray.

Here, in the developing process described above,
As shown in FIG. 2, the collected toner 3a ₂ that remain attached to the developing roller 3c without being transferred to the toner image carrier 1 is moved to the toner supply roller 3b by the rotation of the developing roller 3c. Then, the toner is supplied to the toner scraping blade 3f by the rotation of the toner supply roller 3b, where it is scraped off from the toner supply roller 3b and mixed with the new toner 3a ₁ (toner indicated by ○ in FIG. 2).

[0042] Thus, by being mixed with scraped from the toner supply roller 3b and the new toner 3a ₁ by the collected toner 3a ₂ toner scraping blade 3f, the collected toner 3a ₂ is a toner supply roller 3b developing roller 3
Since the phenomenon which keeps moving between c is avoided, it is possible to prevent deterioration of the collected toner 3a _2.

Therefore, good image quality can be stably obtained.

[0044]

As described above, according to the present invention, the collected toner is scraped off from the toner supply roller by the toner scraping means and mixed with the new toner. The phenomenon that the movement is repeated between the steps is avoided, and the effective effect that the deterioration of the collected toner can be prevented can be obtained.

As a result, an effective effect of stably obtaining good image quality can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an image forming apparatus to which a developing device according to an embodiment of the present invention is attached.

FIG. 2 is an explanatory diagram showing a developing device in the image forming apparatus of FIG. 1 in detail;

FIG. 3 is an explanatory view showing a developing device attached to a conventional image forming apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 toner image carrier 3 developing device 3a toner 3a ₂ collected toner 3b toner supply roller 3c developing roller 3d thinning blade 3f toner scraping blade (toner scraping means)

Claims (3)

[Claims] A developing roller configured to apply toner to a toner image carrier having an electrostatic latent image formed thereon to form a toner image; a toner supply roller configured to supply the developing roller with the toner; And a toner scraping means for scraping the collected toner attached to the toner supply roller. 2. The developing device according to claim 1, wherein said toner scraping means is an elastic plate member, a rigid plate member, or a brush pressed against said toner supply roller. 3. An image forming apparatus to which the developing device according to claim 1 is attached.