JPS5827171A - Developing device in image forming device - Google Patents

Abstract

PURPOSE:To obtain a copied object having a uniform image density by forming a rugged part which is made to coincide almost with the luminous intensity distribution characteristics of image forming at a free end part of a doctor blade. CONSTITUTION:A doctor blade 44 consisting of a non-magnetic material is disposed in a casing 40 of a developing device 19 through stop metal fittings and a rugged part 43 is formed along in a lengthwise direction at its free end part. The pitch of the rugged part 43 is formed so as to be made to almost coincide with the luminous intensity distribution characteristics of a converging optical condutive material 22. The dector blade 44 is arranges so as to regulate the layer thickness of a developer 45 carried by a non-magnetic sleeve 42 and the magnetic force of a magnetic roller 41. By such a constitution, the developer 45 carried by a developing roller is carried in keeping with the luminous intensity distribution characteristics of the conductive material 22 by the rugged part of the doctor blade 44 and the developer 45 is supplied uniformly to an electrostatic latent image of a photoreceptor 18. Consequently, the irregular luminous intensity distribution is not generated also in an original such as a halftone and the image density is uniformed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device in an image forming apparatus such as a copying machine.

Conventionally, in an image forming apparatus such as a copying machine, an image of a copy on a document table is transmitted to an image carrier (hereinafter also referred to as a photoreceptor) via a focusing light transmitter (hereinafter also referred to as a selfoc lens array). configured to irradiate. As shown in FIG. 1, the convergent light transmitting body 1 has a plurality of lenses 2 arranged in two rows with shifted positions, and the light distribution characteristics of the individual lenses 20 of the convergent light transmitting body 1 are shown in FIG. 2. As shown in the figure, the brightness is almost at the center, and the characteristics gradually decrease toward the sides. However, the light distribution characteristics of the convergent light transmitters 1 arranged in two rows in this way are uneven, as shown in FIG. It was found that the light distribution characteristics

Such non-uniform light distribution has the disadvantage that when copying originals such as photographs or halftones, density differences due to the uneven light distribution appear in the image, significantly degrading the image quality. there were.

Therefore, as a solution to this drawback, as shown in Figure 4, the positions of the lenses in the SELFOC 8-lens array are varied mutually to increase the number of rows (four rows in the figure) to make the light distribution characteristics uniform. However, this type of product has drawbacks such as not only being troublesome to manufacture, but also making the product expensive.

This invention has been made based on the above circumstances, and even if the light distribution characteristics of the imaging system are non-uniform, the amount of developer conveyed can be adjusted accordingly, making it uniform. An object of the present invention is to provide a developing device for an image forming apparatus that can obtain copies with a high image density, has an extremely simple configuration, and can supply highly reliable products at low cost. It is.

This invention will be explained from the tables with reference to an embodiment shown in the drawings.

FIG. 5 is a schematic sectional view showing an embodiment of the image forming apparatus of the present invention. In each figure, 10 is an image forming apparatus (hereinafter also referred to as a copying machine), and this image forming apparatus 10
The document table 11 is movable back and forth in two directions of arrows (left and right directions in the drawing) as required. A removable tray 12 is attached to the left side of the copying machine 10 in the figure, and a cassette 1 containing copy paper P is attached to the right side in the figure.
6 and a hand guide 13A are respectively attached. This copying machine 10 includes a paper feed mechanism 14 that feeds copy paper P from a cassette 16 or a hand guide 13A. A transfer mechanism 15 that transfers the developer 45 onto the copy paper P. A transport mechanism 16 that transports the copied copy paper P. A fixing mechanism 17 that fixes the developer transferred to the copy paper P. Photoreceptor such as selenium drum 18. A developing device 19 that stores developer 45 and a cleaning device 20 that cleans the photoreceptor 18. An imaging system consisting of an illumination system 21 that illuminates the document on the document table 11 and a focusing light transmitter 22 that transmits the illumination from the illumination system 21 to the photoreceptor 18; and a charger 23 that charges the photoreceptor 18. The fixed copy paper P is placed in the tray 12.
A conveying roller 24 for conveying the document and a motor 25 for synchronously moving the document table 11 and rotating the photoreceptor 18 are built-in.

! A cooling device 29 for cooling the heat generating portion is installed on the left side of the figure. A paper jam detector (for example, a micro switch) is provided above the cassette 13, and a paper jam detector (for example, a micro switch, not shown) is provided to the left of the fixing mechanism 17 in the figure. . In addition,
The reference numeral 26 in the figure is a paper peeler, 27 is a static eliminator, 28 is a pre-charging exposure lamp, and S is a paper discharge detector. In addition, the device main body 30fd, upper frame 30A, and lower frame 3
0B is pivotally supported at one end, and both frames 3
The other ends of 0A and 30B are at the desired angle θ (for example, 25 degrees)
It is configured to be open. The upper frame 30
A has a photoreceptor 18. Cleaning device 20. Developing device 19. The original table 11 and the like are attached to form an upper unit (1DA), and the lower frame 30B is equipped with cassettes 13. Transfer mechanism 15. The fixing device 17, tray 12, etc. are attached to the lower unit) IO.
After removing the opening/closing door on the front side of the apparatus main body 60, for example, the operation panel (not shown) by rotating it in the front/rear direction of the drawing, the copy paper P is opened via the apparatus main body opening/closing device (not shown). It is configured so that it can be opened and closed in the direction of arrow V (vertical direction in the drawing) with reference to the conveyance path. Therefore, when copy paper becomes jammed on the conveyance path, it is configured so that it can be easily taken out. Note that the transfer mechanism 15 and peeling mechanism 26 provided on the lower frame 30B are connected to the transformer (
It is configured to be electrically connected to and separated from the terminal portion of the upper unit (not shown), and is electrically connected when the upper unit (IQA) is closed, and is electrically disconnected when the upper unit (10A) is opened. There is.

In the apparatus configured in this manner, a copy placed on the document table 11 (hereinafter also referred to as a document) is illuminated by the illumination system 21 and transmitted to the photoreceptor 18 via the convergent light transmitter 22. image is formed on the surface of

Thereafter, the copy sheets P in the cassette 16 or the hand guide member 13A are taken out one by one by the paper feeding mechanism 14 and guided to the lower part of the photoreceptor 18, and the developed image is developed by the developer 45 in the developing device 19. The image is transferred onto the copy paper P by the transfer mechanism 15.

Further, the copy paper P is guided into the fixing mechanism 17 via the conveyor 116 and fixed thereon, and then discharged to the tray 12 via the conveyor p-224.

Note that after the transfer is completed, the photoreceptor 18 is cleaned by a static eliminator 27 and an IJ-ning device 20, and is cleaned by a charger 260.
It will be positioned at a specific location.

The developing device 19 has a casing 40 as shown in FIG.
The magnetic field generating means 41 is located at the lower opening (left end in the figure) of
A developing roll consisting of a moving member 42 and a moving member 42 is disposed, and this magnetic field generating means (hereinafter also referred to as a magnet roll) 41 has a plurality of magnetic poles, and the outer periphery of the magnet roll 41 has a moving member made of a non-magnetic material. A member (hereinafter also referred to as a non-magnetic sleeve) 42 is arranged,
This non-magnetic sleeve 42 is arranged rotatably in the direction of the arrow. Note that the magnet roll 41 may be rotated in the opposite direction (clockwise) to the rotation direction of the non-magnetic sleeve 42. Since the rotational drive device for the developing roll consisting of the non-magnetic sleeve 42 and the magnet roll 41 can employ any known appropriate means, a detailed explanation of its construction will be omitted.

Further, a doctor blade 44 made of a non-magnetic material is disposed in the casing 40 via an indigenous tool such as a screw (not shown), and as shown in FIG. ) has uneven parts 4
6 is formed along the longitudinal direction. This uneven portion 43
The pitch interval is as shown in FIG.
They are formed almost identically to match the light distribution characteristics of the two. That is, the pitch interval of the uneven portions 43 is set in accordance with the pinch interval between the lenses of the SELFOC lens array 22. Further, the convex portion 43α of the uneven portion 43 is aligned with the top portion A of the light distribution characteristic (see FIG. 8) of the lens of the converging light transmitting body 22, while the concave portion 43b is aligned with the bottom portion B of the light distribution characteristic. It will be placed. Note that the shape of the uneven portion 43 provided at the free end of the doctor blade 44 is appropriately determined to have an appropriate shape such as a wavy shape or a sawtooth shape in accordance with the light distribution characteristics of the convergent light transmitting body 22. , but is not particularly limited. The doctor blade 44 is adapted to adjust the layer thickness of the developer 450 conveyed by the magnetic force of the non-magnetic sleeve 42 and the magnet roll 41.

In the rice grain imaging device 19 configured in this way, the developer 45 is conveyed by the developing roller.
At this time, the developer 45 conveyed by the developing roller is transferred to the convergent light transmitting body 2 by the uneven portion of the doctor blade 44.
The developer 45 is conveyed in accordance with the light distribution characteristics of No. 2, and the developer 45 can be uniformly applied to the electrostatic latent image on the photoreceptor 18. As a result, there is no uneven light distribution even for documents such as photographs or halftones, and the image density can be made uniform.

It should be noted that the above embodiment is merely an example, and it goes without saying that each member can be replaced with another member having the same function. For example, although the above embodiment describes an image forming apparatus using a focusing light transmitter, the present invention is not limited to this, and the free end of the doctor blade is The conveyance amount of the developer may be adjusted by forming an uneven portion on the portion. Furthermore, an uneven portion may be formed on the outer peripheral portion of the non-magnetic sleeve 42 in substantially the same manner as the uneven portion of the doctor blade 44, and the conveyance amount of the developer 45 may be adjusted by both. With this configuration, uneven light distribution can be further prevented and high quality images can be formed. Even if the image density is slightly uneven, the amount of developer conveyed can be adjusted accordingly, and copies with uniform image density can be obtained.Moreover, the structure is extremely simple. It has excellent effects such as being able to supply highly reliable products at low cost.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a convergent light transmission body applied to an image forming apparatus, and Fig. 2 shows the light distribution characteristics of the lens.
Figure 3 shows the light distribution characteristics of the convergent light transmitter.
The figure is a perspective view showing another example of a convergent light transmission body, FIG. 5 is a schematic sectional view showing an embodiment of the image forming apparatus of the present invention, FIG. 6 is a sectional view of a developing device, and FIG. FIG. 8, a front view of the doctor blade, is a schematic diagram showing the relationship between light distribution characteristics and the doctor blade. 10... Subject, 18... Photoreceptor, 19.
...Developing device, 20...Cleaning device, 3
0...Device body, 40...Casing, 4
DESCRIPTION OF SYMBOLS 1... Magnet roll, 42... Non-magnetic sleeve, 43... Uneven part, 44... Doctor blade, 45... Developer. 430- 箪ρ M Fig. 8 Appetizer quality

Claims (1)

[Claims] In an image forming apparatus, an electrostatic latent image is formed on an image carrier through an imaging system, and the electrostatic latent image is developed by a developing device having at least a doctor blade. 1. A developing device for an image forming apparatus, characterized in that a concavo-convex portion is entirely formed along a direction intersecting the conveyance direction and approximately matches the light distribution characteristics of the imaging system.