JP3250275B2 - How to adjust the magnetic pole position of the magnet roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser printer, a copying machine, and the like for performing printing using a developer, and relates to a method of adjusting a magnetic pole position of a magnet roller in a developing device.

A magnetic body is arranged at a developing position of a photosensitive drum,
The magnetic material and the developing magnetic pole N of the magnet roller of the developing device
_A magnet roller that can easily and accurately adjust the position of the developing magnetic pole by attracting each other and rotating the magnet roller about the shaft to attract and stop the developing magnetic pole N _1. The method for adjusting the magnetic pole position.

[0003]

2. Description of the Related Art FIGS. 3A and 3B are schematic views showing a magnet roller. FIG. 3A is a diagram showing the arrangement of magnetic poles (as viewed in the direction of arrow C), and FIG.

[0004] magnet with a 3 fixed magnetic pole group including a developing magnetic pole N ₁ as shown in _{(a) (S 1, N} 2, S 2, S 3) 2-1a
Is fixed to the shaft 2-1b as shown in FIG. 3 (b). On the other hand, the sleeve 2-2a is connected to the shaft 2-1b by a pair of flanges 2-2b and ball bearings 2-2c, and a rotation shaft 2-2d is connected to one of the flanges 2-2b.

[0005] Then, the developer is adhered to the outer peripheral surface of the sleeve 2-2a, so rise in the needle by the developing magnetic pole N _1, to perform development in contact with the photosensitive drum. For this purpose, it the developing magnetic pole N ₁ magnetic force must be to maximize the developing position of the photosensitive drum.

As a conventional method, as shown in FIG. 4, a sensor 14-3 for measuring a magnetic force is fixed to a developing position of a developing unit on a position adjusting base 14-1 by using a holding table 14-2. And
The sensor 14-3 is connected to the Gauss meter 14-4 so that the magnitude of the magnetic force can be displayed.

The developing device 1 is mounted on the position adjusting base 14-1, and the positioning projections 14 provided on the base 14-1 are provided.
The developing device reference surface 1-1 is brought into contact of positioning is performed in the developing device in -1a, the size of the developing magnetic pole N ₁ magnetic force, to be displayed on the gauss meter.

In this state, the shaft 2-1b is rotated, and the position at which the maximum magnetic force is generated is detected by the Gauss meter 14-4.
Then, at the detected position, the shaft 2-1b is fixed to the fixing fitting 2-
4, the magnetic pole position of the magnet roller is adjusted by fastening the side plate 1-2 with the screw 2-3b.

[0009]

The conventional magnetic pole position adjusting method described above has the following problems. If the maximum position of the magnetic force of the developing magnetic pole N ₁ and you'll detected in gauss meter, the difference in height is less than around the wave indicating the magnitude of the magnetic force vertex as shown in FIG. 5, also rotates the magnet roller Since the pointer of the Gauss meter 14-4 does not swing and the maximum value continues continuously, it is difficult to detect the optimum magnetic pole position, and it takes time to adjust the magnetic pole position.

Further, the magnetic pole position detector 14, the sensor 14-3 for detecting the position of the developing magnetic pole N ₁ of the magnet roller 2
And a base 14-1 to which a holding table 14-2 of the sensor is fixed, and a Gauss meter 14 for displaying a magnetic force detected by the sensor 14-3.
In this case, the detection device itself becomes large and expensive. In view of the above problems, the present invention eliminates a search operation for detecting a position where a maximum magnetic force is generated by an operator, detects a magnetic pole position where a maximum magnetic force of a magnet roller is generated in a short time, and detects a magnetic pole position with respect to a photosensitive drum. It is an object of the present invention to provide a new magnetic pole position adjustment method for a magnet roller that can be adjusted to an accurate position.

[0011]

According to the present invention, as shown in FIG. 1, a magnet provided with a magnetic pole group including a developing magnetic pole arranged opposite to a photosensitive drum is fixed to a shaft, and the entire circumference of the magnet is fixed. In the method of adjusting the magnetic pole position of the magnet roller in the developing device configured by using the magnet roller in which only the sleeve fitted to the sleeve is fitted, the magnetic material is fixedly arranged at a predetermined developing position determined on the surface of the photosensitive drum, Fixing of the shaft of the magnet roller
A flat surface is provided on the peripheral surface on the fixed end side to be rotatably mounted, and in this state, a predetermined developing position where the developing magnetic pole faces the magnetic material by an attractive force acting between the magnetic material and the developing magnetic pole. It is rotated to, in the rotational position of the shaft
Shaft the long hole at the other end of the fixture with one end fixed to the flat surface.
It was decided to fix it to a predetermined position away from the screw .

[0012]

According to the present invention, the magnetic material 4-3a fixed at the developing position is used.
And a magnet roller 2 that can rotate around the shaft 2-1b
And each other attract the developing magnetic pole N ₁ is, by the magnet over La stops at the developing position, enables accurate up to the magnetic pole position detection, it is readily pole position adjustment of the magnet over la.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is a schematic side view showing a magnetic pole position adjusting method of a magnet roller and an adjusting jig according to the present embodiment.

In FIG. 1, reference numeral 1 denotes a developing device, and 2 denotes a magnet roller. The magnet roller magnet 2-1a having a plurality of fixed pole group including a developing magnetic pole N _1, attached to the shaft 2-1b, fixing bracket 2-4 and screws 2-3a the shaft after the magnetic pole position adjustment completion, It is structured to be fastened to the side plate 1-2 with 2-3b, and only the sleeve 2-2a can be rotated.

3 is for adjusting the magnetic pole position of the magnet roller,
This is a photosensitive drum to be arranged to face the developing device, and is indicated by a two-dot chain line. P indicates a developing position on the surface of the photosensitive drum, and A indicates a rotation center position of the magnet roller.

Numeral 4-3a denotes a magnetic material, the maximum position of the magnetic force of the magnetic material being adjusted to the developing position, and held by a magnetic pole position adjusting jig 4 mounted on a surface plate 5. FIG. 2 is a perspective view of the magnetic pole position adjusting jig 4 of the magnet roller used in the present embodiment.

A magnetic material having a polarity opposite to that of the developing magnetic pole N ₁
4-3a For example, a permanent magnet is fixed to the fixing bracket A4-3b and the fixing bracket B4-
3c and machine screw 4-3d, and link mechanism 4-3f
Unit 4-3 is combined with 4-3g.

In this embodiment, the magnetic pole position adjusting jig 4 has two units mounted on a holding base 4-1. The holding base 4-1 has a contact surface 4-1a that contacts the lower part of the developing device.

Next, the procedure for adjusting the position of the developing magnetic pole when assembling the developing device will be described. As shown in FIG. 1, the method of adjusting the magnetic pole position of the magnet roller using the adjusting jig includes mounting the developing device 1 and the magnetic pole position adjusting jig 4 on which the magnet roller 2 is laterally mounted on a general-purpose platen 5. The contact surface 4-1a of the magnetic pole position adjusting jig 4 is placed on the reference surface 1-1 of the developing device 1.
To perform positioning.

[0020] Then, the developing magnetic pole N ₁ of the magnet roller 2 is rotated about the shaft 2-1b with each other attract each other by magnetic force of the magnet 4-3a. And the developing magnetic pole N
_{When 1} reaches the position facing the developing position, the magnet 4-
The suction force with 3a becomes maximum and the rotation stops.

In this state, one end of the fixing bracket 2-4 is fixed to the flat surface of the shaft 2-1b with the screw 2-3a, and the other end of the developing device holding the magnet roller. Side plate 1-
Insert the long hole shown in Fig. 1 into the screw hole
Fasten with screws 2-3b to fix shaft 2-1.

When the developing device thus adjusted is mounted at a predetermined position of the electrophotographic apparatus, the developing magnetic pole N ₁ is accurately positioned at the developing position. According to the above adjustment, the magnet fixed at the developing position and the developing magnetic pole of the magnet roller rotating about the shaft attract each other by magnetic force, and the magnet roller is rotated until the maximum direction of the magnetic force faces in a straight line. After the magnetic pole position adjusting jig 4 is brought into contact with the developing device 1, the operator waits for the rotation of the magnet roller to stop, and stops the shaft at the stopped position. If it is fixed, accurate positioning is completed. Therefore, the number of assembling steps is significantly reduced, and at the same time, there is no adjustment error.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment, but may be as follows. An electromagnet may be used in place of the magnet described above, and a magnetic field may be generated only when the magnetic pole position is adjusted, and a function may be provided to vary the strength of the magnetic force in order to obtain an optimum magnetic force.

Further, the position and direction of the maximum value of the magnetic force may be further defined by narrowing the width of the intensity distribution of the magnetic force by sharpening the tip of the magnet. Also,
A soft film such as a soft resin such as a synthetic resin may be applied to the tip of the magnet to provide a structure in which protection of both the aluminum sleeve and the jig of the developing device is taken into consideration.

Further, in order to eliminate a magnetic pole positioning error due to a measurement point in the longitudinal direction of the magnet roller 2, a plurality of the magnets 4-3a may be arranged at the developing position in the longitudinal direction of the magnet roller 2.

[0026]

As is apparent from the above description, according to the present invention, the optimum magnetic pole position adjustment of the magnet roller with respect to the photosensitive drum can be instantaneously performed by a very simple method utilizing magnetic force, which is extremely economical and It is possible to provide a method of adjusting the magnetic pole position of the magnet roller, which is expected to improve the reliability.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a method of adjusting a magnetic pole position of a magnet roller and an adjustment jig according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a magnetic pole position adjusting jig of the magnet roller of the present embodiment.

FIG. 3 is a schematic diagram showing a magnet roller.

FIG. 4 is a perspective view showing a conventional magnetic pole position adjusting method of a magnet roller and a detection jig thereof.

FIG. 5 is a diagram for explaining a conventional problem.

[Explanation of symbols]

1 is a developing device, 1-1 is a reference plane, 1-
2 Side plate 2 is a magnet roller, 2-1a is a magnet,
2-1b is a shaft, 2-2a is a sleeve,
2-2b is a flange, 2-2c is a ball bearing,
2-2d is a rotating shaft 2-3a is a screw, 2-3b is a screw, 2-
4 is a fixing bracket, 3 is a photosensitive drum, 4 is a magnetic pole position adjusting jig, 4-1 is a holding base, 4-1a is a contact surface, 4-3 is a magnetic unit, 4-3a is a magnetic material, and 4- 3b is a fixing bracket A, 4-3c is a fixing bracket B, 4-3d is a small screw, 4-3e is a small screw, 4-3f is a link mechanism, 4-3g is a holder, 5 is a surface plate, 14 is a magnetic pole Position detection device, 14-1 base,
14-1a protrusion, 14-2 holder,
14-3 sensor, 14-4 gauss meter

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/09

Claims (6)

(57) [Claims] A magnet provided with a magnetic pole group including a developing magnetic pole disposed opposite to a photosensitive drum is fixed to a shaft, and only a sleeve fitted around the entire circumference of the magnet rotates using a magnet roller. In the method for adjusting the magnetic pole position of a magnet roller in a developing device, a magnetic body is fixedly arranged at a predetermined developing position defined on a surface of the photosensitive drum, and a flat surface is fixed on a peripheral surface of a fixed end side of a shaft of the magnet roller. A surface is provided so as to be rotatable, and in this state, the developing magnetic pole is rotated to a predetermined developing position facing the magnetic body by an attractive force acting between the magnetic body and the developing magnetic pole. In the position, the elongated hole of the other end of the fixing bracket having one end fixed to the flat surface of the shaft
The magnetic pole position adjustment method of the magnet roller which is characterized in that the screw fixed at a predetermined position away from the shaft. 2. The magnetic pole position adjusting method according to claim 1, wherein a tip portion of said magnetic body is formed in a sharp shape. 3. The magnetic pole position adjusting method according to claim 1, wherein a soft coating is applied to a tip portion of the magnetic body . 4. The magnetic pole position adjusting method according to claim 1, wherein said magnetic body is a permanent magnet. 5. The magnetic pole position adjusting method according to claim 1, characterized in that installed side by side a plurality the magnetic material in the longitudinal direction of the magnet rows La. 6. A magnetic pole position adjusting method according to claim 1, wherein an electromagnet is used in place of said magnetic body .