JPH0786722B2 - Development device - Google Patents

Description

The present invention relates to an image forming apparatus using electrophotography, and a lubricant application method used to reduce frictional resistance at a portion where a developing sleeve and a doctor blade contact each other. It is about.

"Prior Art" FIG. 3 is a vertical sectional view of an image forming apparatus such as an electronic copying machine. The document 2 placed on the platen glass 1 that moves in the left-right direction in the figure and pressed by the pressure plate 3 is illuminated by the illumination lamp L partially covered by the reflection shade 4, and the reflected light of the document is An image is formed on the photosensitive drum 6 which rotates in synchronization with the horizontal movement of the original glass 1 in the direction of the arrow in the figure through the short-focus lens array 5. The photosensitive drum 6 is uniformly negatively corona-charged by the primary charger 7, a latent image is formed by the image light, and the toner T is carried and carried out by the developing sleeve 10 in the developing device 8 and is discharged by the doctor blade 9. Then, the toner thickness on the developing sleeve 10 is adjusted and applied to the surface of the photosensitive drum 6, so that the latent image becomes a visible image. Next, when the visible image on the photosensitive drum 6 reaches the surface facing the transfer charger 11, although not shown in detail, it is transferred and separated to a transfer material sent from a paper feeding device, sent to a fixing device, and fixed. It is discharged outside the aircraft. After the transfer, the photosensitive drum 6 rotates to the position of the cleaning device 12, and the cleaning blade 13 removes the residual toner.

The doctor blade 9 is a holding member 9a made of a hard material such as metal or synthetic resin, and an elastic body 9b made of urethane rubber, nitri rubber, polyethylene terephthalate, or the like fixed thereto.

FIG. 4 shows the developing sleeve 10 and the doctor blade 9 shown in FIG.
Shows the relationship. In FIG. 4A, the developing sleeve 10 rotates counterclockwise in a normal state, and the peripheral surface of the developing sleeve 10 moves toward the tip of the doctor blade 9. In FIG. 4 (a), the friction between the doctor blade 9 and the developing sleeve 10 is so large that the contact surface between the doctor blade 9 and the developing sleeve 10 does not slide as shown in FIG. Following the surface, the elastic body 9b of the doctor blade 9 is turned over as shown in FIG. 4 (c).

In order to prevent the above phenomenon, the powder lubricant 20 '(FIG. 5) is applied to the entire area of the developing sleeve 10.

[Problems to be Solved by the Invention] However, the above-mentioned conventional example has the following drawbacks because the lubricant is powder particles having polarity.

(1) As shown in FIG. 5, the powder lubricant 20 'adheres to the surface of the developing sleeve 10. Therefore, when the toner T and the powder lubricant 20 'having a different polarity are used as a lubricant, the toner T is layered on the powder lubricant 20' even if the toner T reaches the surface of the developing sleeve 10. To the photosensitive drum 6 Powder lubricant 2
0'is not developed, and the surface of the developing sleeve 10 is powdered with lubricant 2
The developing sleeve 10 of the toner T becomes polluted with 0 '.
There is a problem when the copy density becomes low because it affects the coating on the.

(2) In a personal copying machine, a part of the image forming apparatus, for example, a process cartridge with the photosensitive drum 6, the primary charger 7, the developing device 8 and the cleaning device 12 as an integrated cartridge, guarantees the product without displaying an image. is doing. Therefore, in the assembly process, a substitute characteristic is measured to guarantee it. Since the mounting position of the doctor blade 9 is also optically measured in the assembly process, it is not possible for the manufacturer of the doctor blade 9 to apply the powder lubricant 20 'in advance and deliver it.

Therefore, although the powder lubricant 20 'is applied in the assembly process, the powder lubricant 20' is applied in accordance with the line tact at the time of assembly, because the powder lubricant 20 'is applied in the assembly process, which may adversely affect the human body due to scattering. There is a large difference in the amount applied depending on the operator.
In addition, unevenness occurs in the applied state due to variations in the operator. In this way, there are restrictions on the process, and there is a risk that the quality may be uneven.

(3) Since the process cartridge is shipped without displaying the image, the toner T in the developing device 8 may be removed from the toner cartridge in the developing device 8 even though there are problems in assembling. If it leaks from the vicinity of the end seal that seals the end of the rotating body and the outside and scatters inside the copier, it will cause trouble. Also, powder lubricant 2
Since 0'is a powder, it scatters in the product and adheres to the primary charger 7 to cause charging failure.

Such a problem is that the powder lubricant 20 'is not fixed on the doctor blade and can be removed by some vibration or wind pressure.

The present invention uses powder particles having the same polarity as a toner as a lubricant and imparts tackiness by using a lubricant dispersed in a volatile liquid so that it can be applied onto a doctor blade. Accordingly, it is an object of the present invention to provide a developing device that solves the above problems.

"Means for Solving the Problem" The present invention applies a volatile liquid in which a powder lubricant charged to the same polarity as a toner is dispersed to a pressure contact portion between a developing sleeve and a doctor blade, and the powder lubricant is used together with the toner. The developing device is configured to be developed.

[Examples] Hereinafter, the present invention will be described based on illustrated examples. First
Drawings (a), (b), (c), (d), and (e) each show the method of applying a powder lubricant.

Elastic body of doctor blade 9 as shown in FIG.
Volatile liquid (eg, CFC 11) that has a white powder lubricant (hereinafter the same) 20 of spherical particles (eg, Tospearl, toner, phenol resin, etc.) that are almost the same as the toner particle size, is dispersed on 9b.
3. Apply alcohol and ethanol (hereinafter the same) 15 with a brush 14.

As shown in FIG. 1 (b), the elastic body 9b of the doctor blade 9 is dipped in the volatile liquid 15 in which the powder lubricant 20 is dispersed, and the surface is coated by a dipping method.

As shown in FIG. 1 (c), the sponge roller 16 containing the volatile liquid 15 in which the powder lubricant 20 is dispersed is rotated and applied onto the elastic body 9 b of the doctor blade 9.

As shown in FIG. 1D, masking 17 is applied to the area other than the application area, and a volatile liquid 15 in which a powder lubricant 20 is dispersed is applied by spraying 18.

As shown in FIG. 1 (e), the volatile liquid 15 in which the powder lubricant 20 is dispersed is used as a powder lubricant by using a roller pump 19.
The liquid 15 is pumped up from the container containing the volatile liquid 15 in which 20 is dispersed, and is discharged from the tip of the nozzle 19a in a fixed amount to uniformly coat the surface of the elastic body 9b of the doctor blade 9.

As described above with reference to FIG. 5, when the toner T used in the product and the powder lubricant 20 'having a polarity different from that of the toner T are used, even if the toner T comes on the developing sleeve 10,
In the structure in which the powder lubricant 20 'remains on the surface 10 and the toner coating on the developing sleeve 10 becomes abnormal, as described above, the elastic body 9b of the doctor blade has the same polarity as the toner T. When the powder lubricant 20 of No. 2 was applied, the phenomenon that the elastic body 9b was turned over disappeared, and the copy density did not decrease. As a matter of course, the powder did not scatter and stain the surrounding area.

This is because, as shown in FIG. 2, the toner T and the powder lubricant 20 are mixed in the developing sleeve 10 because they have the same polarity, so that the layer thickness of the toner T in the developing sleeve 10 is substantially reduced. Conceivable.

The powder lubricant 20 is transferred to the photosensitive drum 6 together with the toner T by the development and developed. After the transfer, the toner T and the powder lubricant 20 remaining on the photosensitive drum 6 are removed by the cleaning device 12.

〔The invention's effect〕

As described above, since the powder lubricant having the same polarity as that of the toner is used, it is developed in the same manner as the toner and disappears from the pressure contact portion between the doctor blade and the developing sleeve, and is not left on the developing sleeve indefinitely. Poor density due to contamination is eliminated. Also, by using a method of dispersing and coating in a volatile liquid, the coating is applied with a certain adhesive force on the doctor blade, so that the powder lubricant will scatter without remaining on the doctor blade. There are no problems.

Further, since the doctor blade is coated with a certain adhesive force, it is not likely that the doctor blade scatters or slips off from the doctor blade due to vibration or wind pressure during the assembly process and transportation.

Therefore, the lubricant can be surely provided between the doctor blade and the developing sleeve, so that the doctor blade is not turned up by the rotation of the developing sleeve.

In the embodiment in the assembling process, when the powder lubricant is applied, the white paint is in the same state as that applied on the doctor blade, so that it is easy to determine the unevenness of the application.

[Brief description of drawings]

1 (a), (b), (c), (d), and (e) are perspective views of an embodiment of the present invention, and FIG. 2 shows a case where a lubricant having the same polarity as the toner is used. Explanatory drawing of the surface of the developing sleeve, FIG. 3 is a longitudinal sectional view of the image forming apparatus, FIG.
(B) and (c) are side views of the conventional example, and FIG. 5 is an explanatory view of a state where the powder lubricant contaminates the surface of the developing sleeve. 8: developing device, 9: doctor blade, 10: developing sleeve, 14: coating brush, 15: volatile liquid in which powder is dispersed, 16: sponge roller, 17: masking member, 18 …… Spray, 20 …… Powder lubricant.

Claims (1)

[Claims] 1. A volatile liquid in which a powder lubricant having the same polarity as that of a toner is dispersed is applied to a pressure contact portion between a developing sleeve and a doctor blade, and the powder lubricant is developed together with the toner. Developing device.