JPH04145471A - Developing device - Google Patents

Abstract

PURPOSE:To obtain a stable image without having a noise by always opposing a main pole position to the nearest position of a developing roller and a photosensitive body even if the developing roller is moved in following up to the eccentricity of the photosensitive body. CONSTITUTION:When the photosensitive body 50 is decentered and moved to the position of a dotted line 50', and the developing roller 1 is moved in the direction of the arrow M centering the shaft 16a of a rocking frame 22a. Therefore, the nearest position X2 is moved to the position of X2'. On the other hand, a magnetic roller is moved together with the movement of the developing roller 1, as well. However, the shaft 4 of the magnetic roller is fixed on a straightening member 26a via an instructing member 32a, and the member 26a is guided by a guiding part 17a, so that the member 26a is rotated in the direction of the arrow R through the use of the center of the guiding part 17a as a fulcrum, while being moved in the direction of the arrow N together with the movement of the roller 1, and the main pole X1 is moved to the position X1a'. Consequently, the main pole position X1 (X1a') and the nearest position X2 (X2') are in coincidence.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device used in an image forming apparatus such as an electrophotographic copying machine.

[Prior art: As shown in FIG. 5.6, a developing roller 100 is made up of a magnetic troller 101 fixed in a non-rotating state, and a sleeve roller 102 that is rotatably mounted on the magnetic troller 101. and the magnetic roller 1
In an image forming apparatus that develops an electrostatic latent image by bringing a two-component developer held on the outer periphery of the sleeve roller 102 into contact with the photoreceptor 200 based on the magnetic force of 01, the sleeve roller 10
2 and the photoreceptor 200 must be kept constant so that a constant amount of developer always comes into contact with the electrostatic latent image.

Therefore, conventionally, the fixed shaft 103 of the magnet roller 101 protruding from the developing roller 100 and the sleeve roller 10
Gap adjustment coils olO, 5, 10, 5 having a slightly larger diameter than the sleeve roller 102 are provided on the drive shafts 104 of No. 2, respectively, and as shown in FIG.
0 is supported so as to be movable toward the center 200a of the photoconductor 200, and the developing roller 100 is biased toward the photoconductor 200 by a biasing means 106 such as a spring. (hereinafter referred to as the "first method"), and the eighth method.
As shown in the figure, a pair of swing frames 1 are attached to the main body of the developing device.
07.107 is provided, one swing frame 107 fixedly supports the magnet roller [Li[103], the other swing frame 107 rotatably supports the sleeve drive shaft 104, and biasing means such as a spring 1. Colo 1 by 08
05° 105 to both ends of the photoreceptor 200 (
Hereinafter, this will be referred to as the "second method." )It has been known.

However, in the first method, when the developing roller 100 moves following the eccentricity of the photoreceptor 200, the gear 111 attached to the sleeve drive shaft 104 and the gear 111 attached to the sleeve drive shaft 104 and the developing device main body or image forming device main body 7. with the gear 112 provided in the.

/Y changes, the developing roller 100 rattles, and the rattle causes noise to appear on the image.

In the second method, the axis 11 of the swinging frame 107.107
4 is provided with a gear 115, and this and the sleeve drive shaft gear 113
Can the disadvantages of the first method be overcome by ensuring a constant amount of torque and/or by meshing the magnet/troller fixed shaft 103 with the swinging frame 107, as shown in FIG. , the sleeve 102 and the photoreceptor 2
A magnetic pole (pole N1 in the figure) that is located behind the developing area Z facing the developing area Z and has the most important effect on development (hereinafter referred to as "main developing pole Nil") moves the developing area Z as the developing roller 100 moves. This results in a situation where the vehicle is moved.

This phenomenon will be specifically explained.

As shown in FIGS. 5 and 9, the center of the main developing pole N1 is located at a position facing the sleeve roller l○2 (main pole opposing position).
, the closest position between the sleeve roller 102 and the photoreceptor 200 is N2, the swinging fulcrum of the developing roller 100 is ○, and the movement locus of the center of the developing roller is C, and the solid line in FIG. It is assumed that the main pole position XIL and the nearest position X2 match.

In this case, the photoreceptor 200 may be eccentric and its outer peripheral surface may be
When it moves to ', 200'', the developing cooler follows this and moves to the position of 100, 100', +00'', respectively. The magnet roller 101 is connected to the swing frame 1.
07, the main pole facing position X1 moves to the xlo, N2'' position with the swing of the frame +07. On the other hand, the closest position X2 between the sleeve roller 102 and the photoreceptor 200 is X2', X2 Move to the '“ position.

Therefore, in the second method, as the developing roller 100 moves, a relative positional shift occurs between the main pole pair same position X1 and the closest position x2, and the image quality changes as the amount of shift changes. There is a problem.

[Problem to be solved by the invention]

Therefore, in a second method, the present invention provides a developing device that can eliminate the relative positional deviation that occurs between the main pole facing position XI and the closest position X2 even if the developing roller moves. The purpose is to

To achieve this object, the developing device of the present invention includes a pair of swinging frames (22a, 22b) swingably supported by a developer tank (12), a magnet roller (2), and a sleeve roller (3). ), and one end side of the spindle (4) of the magnet roller (2) is connected to one swing frame (
22a), and is rotatably supported by the sleeve roller (3).
) of the other swinging frame (22b
), and a developing roller (1) rotatably supported by the photoreceptor (50), which is rotatably supported by the developing roller (
1) toward the photoreceptor (50).
a, 18b), gear holding means (20a, 20b) for maintaining the distance (DS) between the biased developing roller (1) and the photoreceptor (50) at a predetermined value, and the developing tank (1).
2) and a magnetic pole position correction member (2) fixed to the spindle (4) of the magnet roller (2) and guided by the guide member (17a).
6a), and a drive mechanism (37b, 39b) connected to the support shaft (9) of the sleeve roller (3).

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the developing device shown in FIGS. 1 to 3, the developing roller 1 is
It is composed of a magnet roller 2 and a three-way roller 3.

The magnet roller 2 has a magnet 5 attached around the shaft 4, and the outer periphery of the magnet 5 has a plurality of magnetic poles [., Sl, Nl, S2...] extending in the axial direction. is magnetized, and the magnetic pole Nl (hereinafter referred to as "main developing pole Nl") is attached to the photoreceptor 50.
It is located opposite to.

The sleeve roller 3 consists of a cylindrical sleeve 6 and side plates 7 and 10 that cover both ends of the sleeve.One side plate 7 has a bearing 8 disposed inside, a shaft 9 provided at the center of the outside, and the other The side plate 10 is provided with a bearing 11 that penetrates inside and out.

The magnet/troller 2 and the sleeve roller 3 house the magnet roller 2 in the sleeve roller 3, support both ends of the shaft 4 of the magnet roller 2 with bearings 8 and 11, and extend the magnet roller 2 from the other side plate 10. They are combined with one end of the shaft 4 protruding.

A developing roller 1, which is a combination of a magnet/troller 2 and a sleeve roller 3, is housed near an opening 13 provided at the front of a housing 12 of the developing device, and is connected to a fixed shaft 4 of the magnet roller 2 and a sleeve roller protruding from both ends. The drive shafts 9 of No. 3 are inserted into the holes 15a and 15b provided in the housing side walls 14a and 14b, respectively, and the support mechanisms 19a and 19b are inserted.
Each is supported by Note that the holes 15a, 1
5b is formed larger than the shafts 4 and 9, respectively, so that the developing roller 1 can be moved back and forth.

The support mechanism 19a includes a cap adjusting roller 20a, a swing frame 22a, a main pole position correcting member 26a (hereinafter referred to as the "haze correction member 26a"), a main pole position indicating member 32a (hereinafter referred to as the "indicating member 32a"), etc. It is configured.

The other support mechanism 19b is composed of a cap adjustment roller 20b1, a swing frame 22b, and wheels 37b and 39b.

In these support mechanisms 193 and 19b, the cap adjustment flows 20a and 20b have the same outer diameter, and the sleeve 6
It has a slightly larger diameter than the IC, and has through holes 21a and 21b in the middle IC.

The swing frames 22a, 22b have through holes 23a in the upper part,
23b, through-holes 24a, 24b at the bottom, and pressure receiving plates 25a, 25b at the rear, respectively.

The correction member 26a has a through hole 27a in the upper part, a threaded hole 28a in the center, a scale 29a in the lower part, and edges 3Q on both sides.
A and 30a are respectively bent to form a guide groove 31a between them.

The indicator member 32a has a through hole 33a in the upper part, a long hole 34a in the center, and an indicator part 35a in the lower part.

In the support mechanism +98 having the above-mentioned configuration, Kya.

Adjustment roller 20a, swing frame 22a, correction] Y member 2
The fixed shaft 4 of the magnet roller 3 is inserted through the through holes 21a, 24a, and 27a of the magnet roller 6a, and is rotatably supported.

At the same time, the swing frame 22a is rotatably attached to a shaft 16a provided at the upper part of the how/knob side wall 14a through the upper prize passage hole 23a. Further, the pressure receiving portion 25a of the swing frame 22a or the spring 18a provided on the side wall 14a of the knob is pressed, and the cap adjustment roller 20a is brought into contact with the outer peripheral surface of one end of the photoreceptor 50. Further, the cylindrical guide portion 17a provided at the lower part of the how/knob side wall 14a' is positioned in the guide groove 31a of the correction member 26a. Note that the outer diameter of the cylindrical guide portion 17H is the same as the width of the guide groove 31a.

The indicator member 32a is fixed non-rotatably by inserting a through hole 33a into the end of the shaft 4, inserting a bolt 36a into the elongated hole 34a, and inserting the tip of the pin 36a into the screw hole 28a of the correction member 26a. By screwing together, the correction member 26a and the instruction member 32a are fixed. Therefore, the correction member 26a cannot rotate relative to the fixed shaft 4.

The other support mechanism i9b includes a cap adjustment roller 20b,
A drive shaft 9 is inserted into the swing frame 22b and its through holes 21b and 24b so as to be rotatable, and a gear 37b is fixed to the end of the shaft 9. The swing frame 22b is
Similar to the swinging frame 22a on the opposite side, the shaft 1 is located at the upper part of the opening side wall 14b provided symmetrically to the shaft 16a.
It is rotatably supported by 6b. Gear 39b is rotatably supported by shaft 16b and meshed with gear 37b.

Spring +8b is arranged on the housing side wall 14a,
The pressure receiving portion 25b of the swing frame 22b is pressed, and the cap adjustment roller 20b is brought into contact with the outer peripheral surface of the other end of the photoreceptor 50.

The developing roller 1 assembled in the how/puffer 12 as described above has left and right gear knob adjustment rollers 20a, 2Qb.
Both of them contact the photoreceptor 50, and a certain developing cap DS is secured between the three flow and the photoreceptor 50.

When a driving force is transmitted to the gear 39b from a drive system (not shown), the rotation is transmitted to the drive shaft 9 through the gear 37b, and the sleeve roller 2 rotates in the direction of the arrow.

On the other hand, the shaft 4 of the magnet roller 2 is fixed to an indicating member 32a, and the correction member 26 fixed to this indicating member 32a
Since the magnet roller 2 is engaged with the guide member 17a, the magnet roller 2 is fixed in a non-rotating state.

The two-component developer supplied to the outer periphery of the sleeve 6 is held by the magnetic force of the magnet roller 2 and is conveyed to the development area Z according to the rotation of the sleeve roller 3, where it is formed on the outer periphery of the photoreceptor 50. Develop the electrostatic latent image.

The movement of the developing roller 1 following the eccentricity of the photoreceptor 5o will be explained. Now, in FIG. 4, the developing roller 1 and the photoreceptor 5
0 is at the position shown by the solid line, and in this state, the main pole position X1 and the closest position X between the developing roller 1 and the photoreceptor 50
2 or match.

From this state, the photoconductor 50 is eccentric to the dotted line position, :IO
' When the developing roller 1 moves to the swing frame 22
a, 221) with the center of the shafts 16a, 16b as supports for movement in the direction of the arrow -1. Therefore, the nearest position x2
moves to the position X2', similar to the conventional developing device shown in FIG.

On the other hand, the magnet roller 2 also moves together with the movement of the developing roller l. At this time, if the correction member 26a is not present, the magnet roller 2 moves together with the sleeve roller 3, and the main pole position x1 is set to XI' as in the conventional developing device shown in FIG.
Move to the position.

However, since the shaft 4 of the magnet roller 2 is fixed to the correction member 26a via the instruction member 32a, and the correction member 26a is guided by the guide portion 17a, the correction member 26a moves as the developing roller 1 moves. While moving in the N direction, it rotates in the direction of arrow R using the center of the guide portion 17a as a fulcrum, and the main pole position X1 moves to the position Xla'. As a result, the main pole position XI (Xla") is the nearest position X
2 (X2°).

When the photoconductor 50 is eccentrically moved to the opposite side and moved to the position 50'' indicated by the dashed dot line, the developing roller l moves to the swing frame 22a, 22b.
It moves in the direction of the arrow m using the centers of the axes 16a and 16b as fulcrums. Therefore, the closest position X2 moves to the position X2°, similar to the conventional developing device shown in FIG.

On the other hand, the magnet roller 2 also moves together with the movement of the developing roller l. At this time, the correction member 26ah/no correction member 26ah (then the magnet roller 2 moves together with the sleeve roller 3, and the main pole position x1 is set to
Move to the 1°' position.

However, the shaft 4 of the Magne-7 troller 2 is
Since the correction member 26a is guided by the guide portion 17a, the correction member 26a moves in the direction of the arrow n with the movement of the developing roller 1, and the correction member 26a moves in the direction of the arrow n as the developing roller 1 moves. Arrow r with the center as the fulcrum
direction, and the main pole position XI moves to the position Xla''. As a result, the main pole position X I (X] a'') almost coincides with the closest position ffiX2 (X2°°).

In this way, in the developing device, even if the developing roller 1 moves following the eccentricity of the photoreceptor 50, the main pole position x1 always faces the closest position X2 between the developing roller 1 and the photoreceptor 50. Therefore, the contact state of the developer with the photoreceptor 50 in the development area Z is constant, and a stable image without noise can be obtained.

Note that in order to make the main pole position X1 and the closest position X2 almost coincide with each other, the swing radius Ll of the developing roller 1 and the distance L2 from the center of the developing roller 1 to the center of the guide portion 17 must be adjusted.
This is achieved by making them approximately equal.

Further, in the developing device, the image quality can be changed by rotating the magnet roller 2 and adjusting the position of the main developing pole N1 facing the photoreceptor 5o. That is, loosen the bolt 36a in the support mechanism 19a,
By rotating the pointing member 32a with respect to the correction member 26a to change the position of the main developing pole Nl and changing the contact state of the developer with the photoreceptor 50, the image reproduction state can be changed.

Further, the regulating member that adjusts the amount of developer conveyed to the developing area Z may be arranged to face the outer circumferential portion of the sleeve roller 3, or may be located behind the developing roller 1 to control the amount of developer conveyed to the developing roller 1. It is also possible to use another roller for feeding. However, when the developing roller 1 is provided with a regulating member, the shaft 16a is attached to the opposing surface (inner surface) of the housing side walls 14a, 14b.
, 16b are provided, and a pair of frames rotatably provided on these axes support the magnet roller fixing shaft 4 and the sleeve roller drive shaft 9, respectively, and the regulating member is horizontally mounted on these frames. .

In this way, even if the developing roller 1 moves, the gap between the regulating member and the sleeve roller 3 can always be maintained constant.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a developing device equipped with a developing roller that is a combination of a magnet roller and a sleeve roller, even if the developing roller moves following the eccentricity of the photoreceptor, the developing It is possible to maintain a substantially constant positional relationship with respect to the closest position between the developing roller and the photoreceptor.

Therefore, the development characteristics in the development area are constant, and a stable image can always be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially exploded perspective view of the developing device of the present invention. FIG. 2 is a partial perspective view of the developing device of the present invention. FIG. 3: Partial side view of the developing device of the present invention. FIG. 4 is a diagram showing the relationship between the closest position between the developing roller and the photoreceptor and the main developing pole as the developing roller moves in the developing device of the present invention. FIG. 5 A partial vertical sectional view of the developing device. FIG. 6 - Partial cross-sectional view of the developing device. FIG. 7 - A partial side view of a conventional developing device. FIG. 8: A partial side view of a conventional developing device. 9 is a diagram showing the relationship between the closest position between the developing roller and the photoreceptor and the main developing pole as the developing roller moves in the developing device shown in FIGS. 9 and 8. FIG. Developing roller, 2... Magnet roller, 3 Sleeve roller, 4.9, shaft, +2 Housing, 17a Kite part, 18a, 18b-Spring, 19a, i9b
Support mechanism, 20a, 20b cap adjustment roller,
22a, 22b・Swinging frame, 26a・Main pole position correction member, 32a・Main pole position, X2・・nearest position, Z・
development area. Patent Applicant Minolta Camera Co., Ltd. Agent Patent Attorney Ao-Haku Ao Haka 1 person Figure 2 Figure 3 Figure 4a Figure 4 O Figure 9 Figure 5 Figure 6 Figure 105: Gap Adjustment Figure 8

Claims (1)

[Claims] (1) A pair of swinging frames that are swingably supported by a developer tank are combined with a magnet roller and a sleeve roller, and one end of the spindle of the magnet roller is rotatably supported by one of the swinging frames. , one end of the shaft of the sleeve roller is rotatably supported by the other swinging frame, and a developing roller is supported so as to be movable forward and backward relative to the photoreceptor, and the developing roller is biased toward the photoreceptor. a biasing device, a gap maintaining device that maintains a distance between the biased developing roller and the photoreceptor at a predetermined value, a guide member provided in the developer tank, and fixed to a spindle of the magnetic roller; A developing device comprising: a magnetic pole position correction member guided by the guide member; and a drive mechanism connected to a support shaft of the sleeve roller.