JPS58202466A - Developing method - Google Patents

Abstract

PURPOSE:To reduce generation of blocking of a picture, and also to improve image resolution, by setting a rotational frequency ratio of a sleeve and a magnet roll so that a carrying speed of a toner by the magnet roll is equal to or high than its carrying speed by the sleeve, and executing the development. CONSTITUTION:A magnet roll 20 and a sleeve 21 are rotated-driven in the direction B in a developing device 6, but a toner 17 is carried to a developing part 23 in the same direction as a rotating direction of the sleeve 21 by rotation of the sleeve 21 and contacts with a drum 2, but when the magnet roll 20 is rotated in the direction B, the toner 17 is carried in the opposite direction M as indicated with an arrow. In this case, when a rotational frequency ratio of the sleeve 21 and the roll 20 is set so that a carrying speed of the toner 17 by the magnet roll 20 is equal to or higher than its carrying speed by the sleeve 21, generation of a blocking phenomenon is suppressed, and image resolution can be improved.

Description

Detailed Description of the Invention α) Technical Field of the Invention The present invention provides a method for developing an electrostatic latent image using toner, in which the toner is developed using a magnet roll and a sleeve provided to cover the roll. The present invention relates to a developing method applied to an image output device that is transported to a developing section.

(2) Background of the Technology FIG. 1 is a diagram showing an example of an image output device to which the present invention is applied, and FIG. 2 is a sectional view showing details of a developing device.

As shown in FIG. 1, the image output device 1 has a photosensitive drum 2 that is rotationally driven in the direction of the arrow. , a transfer device γ, a static elimination lamp 9, and a cleaner 10 are provided.

The apparatus 1 also includes a paper feed section 11, a paper discharge section 12, and a fixing device 1.
3, etc., and the paper 15 is conveyed by conveyance rollers 16, from the paper feed section 11, through the transfer charger 7, the fixing device 13, and then sent to the paper discharge section 12. On the other hand, as shown in FIG. 2, the developing device 6 has a case 19 containing toner 17, and the case 19 has a large number of magnets 20a arranged in such a manner that adjacent magnets have reversed magnets. The magnets 20 arranged in a circular cross section are arranged in the direction of arrow B opposite to the direction of rotation of the drum 20.
It is supported by a rotationally driven eye in the direction. A sleeve 21 made of a non-magnetic material is placed on the outside of the roll 20.
The sleeve 2 is provided in the case 19 so that it can be rotated freely in the same direction as the arrow B as the roll 20.
A regulating plate 22 that regulates the height of the spikes of toner 17 on the sleeve 21 is provided opposite the sleeve 21 .

Since the image output device 1 has the above-described configuration, the drum 2 is uniformly charged by the charger 3, and then the charge is selectively removed by the optical system 5, so that an electrostatic latent image is formed on the drum 2. is formed. The electrostatic a image is the toner 1 of the developing device 6.
The image is visualized by
Output to. After the transfer by the transfer charger 7 has been completed, the drum 2 is neutralized by the neutralization lamp 9, and the residual toner remaining on the drum 2 is removed by the cleaner 10. On the other hand, in the developing device 6, the magnet roll 20 and the sleeve 2
1 is rotationally driven in direction B, but due to the rotation of the sleeve 21, the toner 17 on the case 19A passes through the gap between the regulating plate 22 and the sleeve 21 in the same direction as the rotation direction of the sleeve 21, and is transferred to the developing section 23. and comes into contact with the drum 2 (indicated by arrow S in the figure). However, when the magnet roll 20 rotates in the direction B, the toner 17 is transferred to the roll 2.
00 rotation direction, that is, from the lower part of the case 190 in the figure, it is conveyed on the sleeve 21 to the developing section 23 (indicated by arrow M in the figure). Normally, the conveyance speed of the toner 17 per rotation is higher than that of the sleeve 21 than that of the magnetic roll 20.
However, how to set the rotational speed ratio of the sleeve 21 and the roll 200 is extremely important in order to obtain a good image bearing state.

(3) Prior art and problems Conventionally, the rotational speed of the sleeve 21 and the roll 20 is determined by the ratio of the sleeve rotational speed 05 to the roll (b) rotational speed nm, which is nm/
ns = 7) s l O below ji'tl ji, s IJ
-F21° [Warping order of conveyance of toner 17 05 force/conveyance speed by rolls 20 was set to be greater than roughness.

Although this is obvious due to the toner transportability, the toner 17 transported by the sleeve 21 violently collides with the regulating plate 22, and the toner 17 becomes tightly encased between the regulating plate 22 and the sleeve 21. The conveyance of the toner 17 to the developing section 23 of the sleeve 21 at the relevant portion on the paper 15 is obstructed, and the phenomenon is no longer carried out, resulting in so-called blocking development in which the image transferred onto the paper 15 comes out in a white strip. There were some drawbacks that could easily occur.

(4) Purpose of the Invention An object of the present invention is to provide a developing method with less occurrence of blocking and excellent resolution in order to eliminate the above-mentioned drawbacks. This is the purpose.

(5) Components of the Invention The present invention is implemented by setting the rotation speed ratio between the two so that the conveyance speed of the magnetic roll is faster than the conveyance speed of the toner by the sleeve. That's why I'm saying this.

Embodiments of the Invention Hereinafter, the present invention will be specifically explained based on embodiments shown in the drawings.

Figure 3 is a diagram showing the relationship between the rotational speed ratio of the magnetic roll and sleeve and the toner conveyance speed, Figure 4 is a diagram showing the relationship between the rotational speed ratio of the magnetic roll and sleeve and resolution, and Figure 5 is a diagram showing the relationship between the rotational speed ratio of the magnetic roll and sleeve and the resolution.
The figure shows the relationship between the rotation speed ratio of the magnet roll and the sleeve and the frequency of blocking occurrence, and FIG. 6 shows the relationship between the rotation speed ratio of the magnet roll and the sleeve and image density.

Normally, the conveyance speed vT of the toner 17 is expressed by the following equation.

VT=V3-Vm,-,,=-(1) However, v:
Toner conveyance speed (m/S)'r v5 Toner conveyance speed by Nisleeve rotation (m/S) m: Toner conveyance speed by magnet roll rotation (m/5) n5 Nislieve rotation speed (rpm) nm: Magnet roll Rotation speed (rpm) D Nice sleeve diameter (mm) P: Number of magnet roll poles h: Height of toner ears (mm) In the above formula, when finding the rotation speed ratio k that makes VT=O, (however, D =32 (mm ), P=12 [pole], h
= 0.5 [mm]), and as shown in FIG. 3, around k=16, the conveyance speed vm of toner 17 by the magnet roll 20 and the conveyance speed ν' of toner 17 by the sleeve 21 are correlated. ,
Furthermore, it can be seen that when k>16, vm≧V.

Next, FIG. 4 shows the relationship between the rotational speed ratio and the degree of resolution. As is clear from this figure, the resolution increases as the rotational speed ratio k increases. Furthermore, as shown in FIG. 5, when the rotational speed ratio k increases, the amount of toner 17 conveyed by the sleeve 21 decreases, and the impact of the toner 1γ colliding with the regulating plate 22 increases. It can be seen that the situation is decreasing rapidly. Next, to show the relationship between image density and rotation speed ratio, as shown in FIG.
It can be seen that a sufficient concentration of gold can be obtained by setting the value to an appropriate value of 16 or more. Furthermore, even in the case of k=16, sufficient i! It is possible to obtain 1 degree and k≧
16, there will be no problem.

(7) As described in detail, according to the present invention, the conveyance speed V5 of the toner 17 by the sleeve 21 is lower than the conveyance speed V5 of the toner 17 by the sleeve 21.
By setting the rotational speed ratio k so that I and feed speed vm at 0 are equal or larger, the occurrence of blocking phenomenon can be greatly suppressed, and a highly reliable developing method can be provided. Not only this, but the resolution can be improved compared to the conventional case where the rotation speed ratio k is 10 or less, and it is possible to reproduce image quality with finer wood grain.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of an image output device to which the present invention is applied, Fig. 2 is a sectional view showing details of a developing device, and Fig. 3 is a rotational speed ratio of the Macnet roll and sleeve and toner conveyance speed. Figure 4 is a diagram showing the relationship between the rotation speed ratio of the magnet roll and sleeve and the resolution. Figure 5 is a diagram showing the relationship between the rotation speed ratio of the magnet roll and sleeve and the frequency of blocking occurrence. The figure is a diagram showing the relationship between the rotational speed ratio of the magnet roll and the sleeve and the image # degree. 1...-Image output device 17...Toner 20...Macnet roll 21...-Sleeve 23...Development section k... ...Rotation speed ratio V, , Vm...Conveyance speed Applicant Fujitsu Ltd.

Claims (1)

[Claims] q) Rotationally driven magnet roll and the roll'
An image output device that has a sleeve that is provided in a teat shape and is rotationally driven in the same direction as a magnet roll, and that conveys toner to a developing section by rotation of the magnet roll and sleeve to develop an electrostatic a image, A developing method characterized in that development is carried out by setting a rotational speed ratio between the two so that the conveying speed of the toner by the magnetic roll is equal to or greater than the conveying speed of the toner by the sleeve. (2) The developing method according to claim 1, wherein the rotation speed ratio between the magnet roll and the sleeve is set to 16 or more.