JPH10239997A - Developing unit - Google Patents

Abstract

(57) [Problem] To prevent scratches on a photoreceptor due to an end of a developing roller. SOLUTION: A case 230 accommodating toner, a developing roller 211 rotatably supported by a shaft 212 in the case 230, a regulating blade 260 for regulating the amount of toner on the developing roller 211, and a developing roller 211 are provided. The developing roller 211 of the developing device is provided with a seal member 270 provided at the side end and preventing the toner from leaking out of the case from the shaft portion. The amount of elastic displacement of the developing roller 211
To be larger than the chamfer amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a printer, a facsimile, and a copying machine for forming an image by using an electrophotographic technique.

[0002]

2. Description of the Related Art Generally, an image forming apparatus using an electrophotographic technique includes a photosensitive member having a photosensitive layer on an outer peripheral surface, a charging device for uniformly charging the outer peripheral surface of the photosensitive member, and one charging device. Exposure means for selectively exposing the charged outer peripheral surface to form an electrostatic latent image, and applying a toner as a developer to the electrostatic latent image formed by the exposure means to form a visible image The image forming apparatus includes a developing unit that forms a (toner image), and a transfer unit that transfers the toner image developed by the developing unit to a transfer medium such as paper.

The conventional developing means includes a case containing toner, a developing roller rotatably supported on the case by a shaft, a regulating blade for regulating the amount of toner on the developing roller, There is known a device provided with a seal member provided at an end of the developing roller side to prevent toner from leaking out of a case from a shaft portion of the developing roller.

[0004]

In the above-mentioned conventional developing device, in the known contact type developing method in which the developing roller and the photosensitive member come close to or come into contact with each other, the edge of the toner conveying surface of the developing roller is in contact with the photosensitive member. There is a problem that the photoconductor is scratched by direct rubbing. Particularly, when the developing roller uses a rigid body such as a metal, not only in the contact type developing method but also in the non-contact type developing method, depending on the runout accuracy of the developing roller and the photoreceptor, the photoreceptor is scratched. Sometimes.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a photoreceptor that does not have scratches or the like.
An object of the present invention is to provide a developing device having a good sealing property.

[0006]

According to a first aspect of the present invention, there is provided a developing device, comprising: a case containing a toner; a developing roller rotatably supported by a shaft in the case; A regulating blade for regulating the amount of toner on the roller, and a seal member provided at a side end of the developing roller, for preventing toner from leaking out of the case from a shaft portion thereof, wherein An end portion of the toner conveying surface of the developing roller is chamfered, and an amount of elastic displacement of the seal member is larger than the amount of chamfering.

[0007]

According to the developing device of the present invention, since the end of the toner conveying surface of the developing roller is chamfered, the end of the developing roller does not come into contact with the photosensitive member. Therefore, it is possible to prevent the photosensitive member from being scratched due to the rubbing of the edge of the end portion of the developing roller. Furthermore, since the amount of elastic displacement of the seal member is larger than the amount of chamfering at the end of the developing roller, the sealing member flexibly follows the chamfered portion at the end of the developing roller. And the toner sealability is further improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 is a schematic diagram showing an example of an image forming apparatus using a developing device according to a first embodiment of the present invention.

First, the outline of the image forming apparatus will be described, and then the developing unit and the developing device incorporated in the unit will be described in detail.

[0011] This image forming apparatus includes a yellow, cyan,
This is an apparatus that can form a full-color image using a developing device using magenta and black toners.

In FIG. 1, reference numeral 50 denotes a case of the apparatus main body. In the case 50, an exposure unit 60, a sheet feeding device 70, a photosensitive unit 100, a developing unit 200,
An intermediate transfer unit 300, a fixing unit 400, and a control unit 80 for controlling the entire apparatus are provided.

The photoconductor unit 100 includes a photoconductor 110
A charging roller 120 serving as a charging unit for uniformly charging the outer peripheral surface by contacting the outer peripheral surface of the photoconductor 110; and a cleaning unit 130.

The developing unit 200 includes:
Developing unit 210Y for yellow, developing unit 210 for cyan
C, a developing device 210M for magenta and a developing device 210K for black. Each of these developing devices 210Y, 21
0C, 210M, and 210K have yellow, cyan, magenta, and black toners built therein, respectively. Further, the developing rollers 211Y, 211C, 2
11M and 211K, so that only the developing roller of any one of the developing units can contact the photoconductor 110.

The intermediate transfer unit 300 includes a driving roller 3
10, primary transfer roller 320, wrinkle removing roller 330
, Tension roller 340 and backup roller 3
50, an endless intermediate transfer belt 360 stretched around each of the rollers, and a cleaning unit 370 that can come into contact with and separate from the intermediate transfer belt 360.

A secondary transfer roller 380 is disposed opposite to the backup roller 350. The secondary transfer roller 380 is rotatably supported by an arm 382 that is swingably supported by a support shaft 381.
By swinging by the operation of the cam 383, the cam 383 comes into contact with and separates from the intermediate transfer belt 360.

The drive roller 310 has a gear (not shown) fixed to an end thereof. The gear meshes with a gear (not shown) of the photoconductor unit 100, so that the drive roller 310 and the photoconductor 110 are in contact with each other. The intermediate transfer belt 360 is driven to rotate at substantially the same peripheral speed as that of the photoreceptor 110.

While the intermediate transfer belt 360 is being driven to circulate, the toner image on the photosensitive member 110 is transferred between the primary transfer roller 320 and the photosensitive member 110 by the intermediate transfer belt 36.
The toner image transferred onto the intermediate transfer belt 360 is transferred onto a recording medium S such as a sheet supplied between the secondary transfer roller 380 and the toner image. The recording medium S is supplied from the sheet feeding device 70.

The paper feeding device 70 includes a tray 71 on which a plurality of recording media S are placed in a stacked state, a pickup roller 72, and a recording medium S placed on the tray 71 facing the pickup roller 72. It has a hopper 73 for urging and a pair of separation rollers 74 for surely separating sheets fed by the pickup roller 72 one by one.

The recording medium S fed by the paper feeding device 70
Passes through a first pair of conveying rollers 91, a first sheet sensor 91S, a second pair of conveying rollers 92, a second sheet sensor 92S, and a pair of gate rollers 93 through the second transfer section, ie, the intermediate transfer belt 360 and the secondary transfer roller 380. And then discharged onto the case 50 via the fixing unit 400, the first pair of paper discharge rollers 94, and the second pair of paper discharge rollers 95.

The fixing unit 400 includes a fixing roller 410 having a heat source and a pressing roller 42 pressed against the fixing roller 410.
0.

The operation of the entire image forming apparatus as described above is as follows.

(I) When a print command signal (image forming signal) from a host computer (personal computer or the like) (not shown) is input to the control unit 80, the photosensitive member 1
10, the developing roller of the developing unit 200 and the intermediate transfer belt 360 are rotationally driven.

(Ii) The outer peripheral surface of the photoconductor 110 is uniformly charged by the charging roller 120.

(Iii) The outer peripheral surface of the uniformly charged photoreceptor 110 is subjected to selective exposure L according to image information of the first color (for example, yellow) by the exposure unit 60, and a yellow electrostatic latent image is formed. An image is formed.

(Iv) The developing roller 211 of the developing device 210Y for the first color (for example, yellow) is provided on the photosensitive member 110.
Only the Y contacts, the electrostatic latent image is developed, and the toner image of the first color (for example, yellow) is
10 is formed.

(V) The toner image formed on the photosensitive member 110 is transferred onto the intermediate transfer belt 360 at a primary transfer portion, that is, between the photosensitive member 110 and the primary transfer roller 320. At this time, the cleaning units 370 and 2
The next transfer roller 380 is separated from the intermediate transfer belt 360.

(Vi) After the toner remaining on the photosensitive member 110 is removed by the cleaning means 130,
The photoconductor 110 is neutralized by the neutralization light L ′ from the neutralization unit (see 61 in FIG. 2).

(Vii) The above operations (ii) to (vi) are repeated as necessary. That is, the second color, the third color, the fourth color,
Are repeated, and a toner image corresponding to the content of the print command signal is formed on the intermediate transfer belt 360 in a superimposed manner.

(Viii) The recording medium S is supplied from the paper feeding device 70 at a predetermined timing, and immediately before or after the leading end of the recording medium S reaches the second transfer portion (in short, a desired position on the recording medium S) Then, at the timing when the toner image on the intermediate transfer belt 360 is transferred, the secondary transfer roller 380 is pressed against the intermediate transfer belt 360, and the toner image on the intermediate transfer belt 360 (basically a full-color image)
Is transferred onto the recording medium S. Further, the cleaning unit 370 comes into contact with the intermediate transfer belt 360, and the toner remaining on the intermediate transfer belt 360 after the secondary transfer is removed.

(Ix) The recording medium S is in the fixing unit 400
, The toner image is fixed on the recording medium S, and then the recording medium S is discharged onto the case 50 via the pair of paper discharge rollers 94 and 95.

The outline of the image forming apparatus has been described above. Next, details of the developing unit 200 and the developing device will be described.

As shown in FIG. 1, the developing unit 200 includes a substantially inverted “L” -shaped frame 220 and the four developing units 210 (Y, C, and M) detachably attached to the frame 220. , K).

As shown in FIG. 1, the frame 220 of the developing unit 200 is configured to be rotatable in the direction of arrow a1 (counterclockwise) by a shaft 221. Locked to the position shown in.

Since the cover 54 of the case 50 is also openable in the direction of arrow a by the hinge 54a (54b indicates the end of the cover 54 in FIG. 1), the cover 54 is opened. Thus, any developing device 210 can be attached to and detached from the frame 220 in a substantially horizontal direction without rotating the frame 220. Further, the cover 54 and the developing unit 200
The photoconductor unit 100 can be attached and detached in a state where is opened in the directions of the arrows a and a1.

FIG. 2 shows four developing units 210 (Y, C,
M, K), an enlarged view of the photoconductor 110 and its periphery, and FIG. 3 is an enlarged view of the developing unit 210M. Also,
4 is a partially omitted IV-IV sectional view in FIG. 3, and FIG. 5 is a partially omitted VV enlarged sectional view in FIG.

Four developing units 210 (Y, C, M, K)
Although the shape and the like are slightly different, since the basic structure is the same, a magenta developing device 210M is represented. Referring mainly to FIG. The following description focuses on the configuration.

The developing device 210 includes a case 230, the toner T stored in the case 230, a developing roller 211 for supplying the toner T to the surface of the photoconductor 110, and a toner T for supplying the developing roller 211. Supply roller 24
0, three transfer fins 251, 252, and 253 for transferring the toner T toward the supply roller 240;
A regulating blade 260, which is pressed against the developing roller 211 to regulate the amount of toner on the developing roller, and a seal member 270 (not shown) for preventing toner leakage between the shaft of the developing roller, the supply roller, and the transfer fin and the case. ).

The case 230 is a case body (lower case).
231 and a lid 232.

As described above, in the conventional developing device, in the known contact type developing method in which the developing roller and the photosensitive member come close to or come into contact with each other, the edge portion of the end of the toner conveying surface of the developing roller directly rubs against the photosensitive member. However, there is a problem that the photosensitive member is scratched. Particularly, when the developing roller uses a rigid body such as a metal, not only in the contact type developing method but also in the non-contact type developing method, depending on the runout accuracy of the developing roller and the photoreceptor, the photoreceptor is scratched. Sometimes.

Therefore, in the first embodiment, the following is performed.

As shown in FIG. 5, the end of the developing roller 211 is chamfered with an R, and the R is set to 0.2 mm.
And Next, as shown in FIG. 4, the toner conveying surface length of the developing roller 211 is shorter than the regulating blade 260. The shaft 212 is rotatably supported on the side walls 231a, 231a of the case main body 231 via bearing members 232, 232. The developing roller 21 is attached to one end of the shaft 212.
A gear 213 for rotationally driving 1 is fixed,
A transmission gear 214 for transmitting power from a drive source (not shown) meshes with the gear 213. Further, rollers 215 are rotatably provided at both ends of the shaft 212. When the developing roller 211 contacts the photoconductor 110 as described later, the roller 215
The position of the developing roller 211 with respect to the photoconductor 110 is regulated by abutting on flanges (not shown) provided at both ends of the “0”.

As described above, the regulating blade 260 is longer than the toner conveying surface of the developing roller 211. Further, the regulating blade 260 is fixed to the tip 261a of the support plate 261 as shown in FIG. Support plate 261
The bent rear end 261b is
3 hook portions 262 of the base plate 262 fixed to
By being supported by b (see FIG. 4), it can swing about this support portion. Then, the support plate 261 is controlled by at least two (three in the figure) tension springs 263 provided between the intermediate portion 261c and the front portion 262a of the base plate 262.
60 is urged so as to press against the developing roller 211.

The shaft 212 of the developing roller 211 is rotatably supported on the side wall 231a of the case main body 231.
Since at least one end penetrates the side wall 231a, a seal member 270 for preventing leakage of toner is provided in this portion. In this embodiment, FIG.
As shown in (a), the sealing member 270 is formed by laminating a sheet-like foam material 271 and a raised material 272, and a sealing pressure is mainly obtained by the foam material 271.
It is arranged at the side end of the developing roller 211 so as to obtain a sealing function mainly by the raised material 272. In this embodiment, in order to achieve more efficient toner sealing, the amount of elastic displacement of the seal member is set to be larger than the amount of chamfering at the end of the developing roller 211. More specifically, the elastic displacement of the bristle material 272 of the seal member 270 is set to be larger than the end chamfer of the developing roller 211.
In the present embodiment, since the chamfer R is 0.2 mm, the length of the bristle agent 272 is set to 2 mm and is set within the elastic displacement amount.

In the first embodiment, as described above, since the end of the developing roller is chamfered, the end of the developing roller does not come into contact with the photosensitive member. Therefore, it is possible to prevent the photosensitive member from being scratched due to the rubbing of the edge of the end portion of the developing roller. Furthermore, since the amount of elastic displacement of the seal member is larger than the amount of chamfering at the end of the developing roller, the sealing member flexibly follows the chamfered portion at the end of the developing roller. And the toner sealability is further improved.

Further, in the present developing device, since the sealing is performed at the developing roller side end, it is possible to prevent toner from sneaking around from the toner conveying surface of the developing roller to the side end.

Accordingly, unlike the conventional case, the photosensitive member is not scratched by the end of the developing roller, and a good toner seal can be obtained.

Next, the supply roller will be described.

The supply roller 240 is, as shown in FIG.
The shaft 241 is connected to the side wall 23 of the case main body 231 via bearing members 242 and 242 (only one is shown in FIG. 5).
1a and 231a rotatably supported. Shaft 241
A gear 243 for rotationally driving the supply roller 240 is fixed to one end of the drive gear. A transmission gear (not shown) for transmitting power from a drive source (not shown) meshes with the gear 243.

The transfer fins 251, 252, 253 (FIG. 3)
) Have basically the same configuration, and similarly to the supply roller 240 described above, the side walls 231a and 231a of the case main body 231.
A shaft 254 rotatably supported by the shaft 31a;
4, a thin (sheet-like) flexible fin 256 fixed to the tip of the arm 255, and a gear or ratchet fixed to the shaft 254 outside the case 231. 3, and is driven to rotate in a direction indicated by an arrow in FIG. 3 by a driving source (not shown). The transfer fins 251, 252, 2
The rotation speed of 53 is 1/20 of the rotation speed of the supply roller 240.
It is about 1/50.

A substantially semi-cylindrical toner storage portion 233 is provided in the case main body 231, and the fin 256 of the rotating transfer fin is fixed to a wall surface 233 a of the toner storage portion 233.
The toner T is transported so as to be held in the wedge-shaped space 233b formed by sliding contact with the toner.

That is, the toner T is transferred to the transfer fins 253.
→ 252 → 251 → supply roller 240, and is supplied to the developing roller 211.

As described above (see FIGS. 1 and 2), the developing unit 210 as described above is a developing unit 210Y for yellow,
210C for cyan, 210M for magenta,
4 frames for black 210K, frame 22
0 is detachably attached.

In FIG. 2, 222 (Y, C, M, K)
Is a receiving plate of each developing unit 210 (Y, C, M, K). A pair of side plates (not shown) are integrally formed on the receiving plate 222. As shown in FIG. 6, the receiving plate 222 is moved relative to the frame 220 by a shaft 223 protruding from the outer surface of the side plate. It is mounted so that it can swing.
A tension spring 224 is provided between the side plate and the frame 220.
6, the developing roller 211 of the developing unit 210 fixed to the receiving plate is urged in a direction in which the developing roller 211 is pressed against the photosensitive member 110. At least one side plate is provided with a cam pin 225. The cam pin 225 is provided on the cam 22 provided on the frame 220.
Due to the contact with 6, the swing is restricted. The cam 226 is rotatably driven by driving means (not shown). When the cam 226 is at a position shown by a solid line in FIG. 6, the developing roller 211 is pressed against the photosensitive member 110 by the urging force of the spring 224, Is in the position shown by the imaginary line in FIG.
The developing roller 211 is separated from the photoconductor 110 by swinging the counterclockwise direction.

This cam structure is used for all the receiving plates 222
(Y, C, M, K), so that only one developing roller 211 is brought into contact with the photoconductor 110 by controlling the rotation of the cam. Can be.

The shaft 223 and the cam pin 225
May be provided on the case main body 231 of the developing device 210.

In FIG. 2, reference numeral 180 denotes the photosensitive unit 1
00 subframe, and the subframe 180
In addition, a charging roller 120 and a cleaning unit 130 are incorporated.

The cleaning means 130 includes the photosensitive member 110
Fur brush 131 for removing the toner remaining on and adhering to the outer peripheral surface of the photoreceptor 110, and a cleaner blade 1 for scraping off the toner remaining and adhering to the outer peripheral surface of the photoconductor 110
32, and a toner conveying screw 133 as conveying means for conveying the toner brushed off or scraped off by the fur brush 131 or the cleaner blade 132.

A toner collecting chamber 182 is formed below the sub-frame 180.
Inside the fur brush 131, the cleaner blade 13
2 and a toner conveying screw 133 are disposed.

The fur brush 131 is mounted on the sub frame 18.
0 is fixed to a shaft 131a passing through the side plate of
When 1a is driven by a driving unit (not shown), it is rotationally driven in the direction of the arrow in FIG.

The cleaner blade 132 is attached to the mounting plate 132
a attached to the sub-frame 180 by a
The leading end (lower end) contacts the outer peripheral surface of the photoconductor 110 to scrape off the toner.

The toner conveying screw 133 is driven to rotate in a direction indicated by an arrow in FIG. 2 by a driving unit (not shown), and conveys the toner collected in the toner collecting chamber 182 to a waste toner box (not shown) as waste toner.

Further, in the present embodiment, various measures can be made or made, so that the description will be made below.

<Regarding the Arrangement of the Developing Unit 210> As shown in FIG. 2, the toner is transported to the developing roller 211 by means of the rotation center of the supplying roller 240 as a means for supplying the toner and the toner to the supplying roller 240 by being lifted or lowered. Assuming that the angle between the line S connecting the rotation center of the transfer fin 251 as a means and the horizontal line H is θ, all the developing devices 210 (in this case, Y, C,
M and K), the developing unit 210 is arranged so that θ is in the range of −20 ° <θ <75 °. Note that θ is + in the clockwise direction with respect to the horizontal line H.

If θ is -20 ° or less, the transfer fin 2
This is because there is a possibility that toner transfer failure from 51 to the supply roller 240 may occur. Conversely, if θ is 75 ° or more, the toner is excessively transferred toward the supply roller 240,
This is because the toner may be in a powder state. The powder state means that the developing roller 211 and the supply roller 24
0, and a phenomenon in which the space formed by the regulating blade 260 is filled with toner, and the pressure of the space is increased by the toner. In the case of the powder state, the toner on the developing roller cannot be limited to an appropriate amount by the regulating blade, and the toner overflows from the regulating portion.

If θ is within the above range, the supply roller 24
0, the toner is appropriately supplied to the developing roller 211, so that a plurality of developing devices 210 can be arranged around the single photoconductor 110, and as a result, the idle High-speed image formation with a short time is possible. The diameter of the photoconductor 110 is φ80.
It should be in the range of 90 mm.

The range of the above θ is more preferably in the range of −12 ° <θ <56 °.

<Regarding the Transfer Fins 251, 252 and 253> As described above, the toner in the case body 231 is
The fins 256 of the rotating transfer fins are
3 is transported so as to be embraced by a wedge-shaped space 233b formed by sliding contact with the wall surface 233a of
Since the fins 256 are formed in a flexible thin plate (sheet shape), the fins 256 are
3 is removed from the wall surface 233a.
The toner transported while being held by the fins 3 b is released by being repelled by the resilience of the fins 256, and the output power of the fins 25 is
6 depends on the rigidity (elasticity).

Therefore, (1) the fins 25 of the transfer fins 251, 252, 253
The rigidity of No. 6 is as follows.

That is, the developing device 210 (for example, the developing device 210
Regarding K), the rigidity (restoring force due to elasticity) of the fins 256 of the transfer fins 251, 252, 253 is relatively strong.

Conversely, with respect to the developing device 210 (for example, the developing device 210Y) arranged so that the angle θ becomes large, the fins 2 of the transfer fins 251, 252, and 253 are used.
The rigidity (restoring force due to elasticity) of 56 is relatively weak.

With this configuration, it is possible to further optimize the transfer amount of the toner.

In particular, the fin 256 of the transfer fin 251 for transferring the toner to the supply roller 240 preferably has the above-described configuration.

(2) Transfer fins 251, 252, 253
With regard to the above, the rotational load is equalized by making the rotational phases different from each other.

Specifically, when n toner transfer means are connected in series (in this case, n = 3), the fins 25 are shifted by shifting the angle of the transfer fins of the n transfer means by 360 ° / n.
The rotation load can be equalized by making the sliding contact length in which the sliding member 6 slides in contact with the wall surface 233a substantially constant regardless of the angles of the transfer fins 251, 252, 253.

(3) At the portion where the fin 256 starts sliding contact with the wall surface 233a, the rotational torque can be reduced by forming the wall surface 233a such that the deflection of the fin 256 gradually increases. .

(4) If a portion of the fin 256 that deviates from the wall surface 233a has a shape of the wall surface 233a such that the bending of the fin 256 is gradually released, the transfer amount (discharge strength or discharge amount) of the toner is reduced. As a result, excessive transfer of the toner in the developing device 210 (for example, the developing device 210Y) in the posture of scraping and transferring the toner can be prevented, and the dusting phenomenon can be prevented.

<Regarding the swing support structure of the developing roller 211 and the developing device 210> The developing roller 211 has a diameter of φ15.
SUS of up to 25 mm (more preferably about φ18 mm)
Alternatively, it was formed of an AL material, and its surface was given a roughness suitable for supporting the toner by blasting or chemical polishing.

Further, as shown in FIG. 6, the developing roller 211 rotates so as to rotate with respect to the photosensitive member 110, and its peripheral speed is 1.5 to 2.5 with respect to the peripheral speed of the photosensitive member 110.
Times (more preferably about twice).

As a result, the force F1 due to the reaction acts on the developing device 210. In order to prevent the force F1 from acting in the biting direction, the swing center O3 of the developing device 210 is controlled.
The rotation center O2 of the developing roller 211 is smaller than the line S2 connecting the (shaft 223) and the rotation center O1 of the photoconductor 110.
However, the developing roller 211 is configured to be positioned on the side of the force F1 in the direction of action, and the developing roller 211 is separated from the side in the direction of the action of the force F1.

<Regarding Supply Roller 240> (1) The supply roller 240 is made of a porous elastic body (for example, a foamed member such as urethane), carries toner on its surface, and rubs it against the developing roller 211. It was configured to be supplied as described above.

Here, it is desirable that the supply roller 240 is such that the lower half thereof is buried in the toner (the upper half is exposed from the toner surface) in order to supply the toner to the developing roller 211.

Further, by setting the peripheral speed of the supply roller 240 to about 50% to 80% (more preferably, about 60% to 70%) with respect to the peripheral speed of the developing roller 211, toner is supplied to the developing roller 211. In addition, the toner properties can be ensured, and the deterioration of the toner can be prevented.

(2) As described above, the developing roller 211
Shaft 212, the shaft 241 of the supply roller 240, and each shaft 254 of the transfer fins 251, 252, and 253 are rotatably supported by the side wall 231a of the case main body 231. Therefore, it is necessary to provide a seal member at this portion to prevent leakage of toner.

On the other hand, since the supply roller 240 is made of a porous elastic material, the pressure contact portion 240a with the developing roller 211 is in a concave state as shown in FIG. This state is schematically shown in FIGS. 7 (a) and 7 (b).

As can be seen from this figure, the supply roller 24
In the portion 0, the end is protruded to the side as shown in FIG.
The protrusion is indicated by 240b.

The protrusion 240b acts so as to bite into the seal member SE.
This leads to an increase in the drive torque of the forty.

Therefore, in this embodiment, as shown in FIG. 5, the corner 244 of the supply roller 240 is chamfered. The chamfer (244) may be a straight one as shown, or may be round (with R).

With this configuration, the above-described biting can be prevented, and the supply roller 2
The drive torque of the forty can be reduced.

When the bite occurs as described above, a gap C is formed between the seal member SE and the end face of the developing roller 211 at the bite portion as shown in FIG. And the sealing performance is reduced, and the end of the developing roller 211 is stained with toner. However, according to this embodiment, such a problem can be prevented beforehand. That is, while improving the sealing property, the developing roller 2
11 can be prevented from toner contamination.

<Regarding the Seal Member> As described above, the shaft 212 of the developing roller 211 and the shaft 24 of the supply roller 240
1 and each axis 2 of the transfer fins 251, 252, 253
54 is rotatably supported on the side wall 231a of the case main body 231 and at least one end thereof is connected to the side wall 231a.
Therefore, it is necessary to provide a seal member at this portion to prevent leakage of toner.

In this embodiment, as shown in FIG. 5A, the seal member 270 is
1 and the raised material 272 are bonded together, the sealing pressure is mainly obtained by the foam material 271, and the sealing action is mainly obtained by the raised material 272.

FIG. 5B is a view taken in the direction of the arrow b in FIG. 5A, and the roller end (the end of the supply roller 240 in this case).
FIG. 4 is a diagram schematically illustrating a state of a raised material 272 between the foam material 271 and the foam material 271.

As can be seen from this figure, the raised material 272
The raised 273 has a discontinuous spiral shape as the roller rotates, so to speak, a labyrinth seal.

Therefore, leakage of the toner is reliably prevented.

[0096] Moreover, since the raised 273 follows the rotation of the roller, the rotation torque of the roller is also reduced.

Although not shown in FIG. 5, the seal member 270 is similarly provided on the axes of the transfer fins 251, 252, and 253.

In FIG. 5A, reference numeral 274 denotes a sheet-like lubricant made of a fluorine-based low friction material.

<Regarding the Drive Structure of the Developing Roller 211> As shown in FIG. 4, the shaft 212 of the developing roller 211 is supported by the side walls 231a and 231a of the case main body 231 via bearing members 232 and 232, A transmission gear 214 for power transmission meshes with a gear 213 fixed to one end thereof. The roller 2 is provided at both ends of the shaft 212.
15 is provided rotatably.
When the developing roller 211 is pressed against the photosensitive member 110 as shown in FIG. 6, the developing roller 211 comes into contact with flanges (not shown) provided at both ends of the photosensitive member 110 (or outside the image forming area of the photosensitive member). Thus, the position of the developing roller 211 with respect to the photoconductor 110 is regulated.

Therefore, the developing roller 211 is
10, a lateral load acts on the shaft 212 supported by the rollers 215 and 215 at both ends via the case body 231 and the bearing members 232 and 232.
The shaft 212 may be bent.

Here, if no measures are taken, the meshing state between the gear 213 and the transmission gear 214 may become unstable due to the bending of the shaft 212.

Therefore, in this embodiment, as shown in FIG. 4, reference surfaces 213a and 214a are provided on the gear 213 and the transmission gear 214, respectively, and the gears 213 and the transmission gear 214 are brought into contact with each other. To stabilize the meshing state.

<Others> (1) The mounting positions of the developing units 210 can be clarified by making them different in shape or color. (2) When the developing device 210 is taken out, the developing device pops up by a predetermined amount in the taking-out direction, so that the developing device 210 can be easily taken out. (3) The developing device 210 is thinned to such an extent that the operator can easily grasp it with one hand, and the detaching operation is facilitated.

<Second Embodiment> FIG. 8 is a schematic diagram showing a main part of an image forming apparatus using a developing device according to a second embodiment of the present invention.

The difference between the second embodiment and the first embodiment is that the developing device 210 for black is different from the first embodiment.
It is at K 'and the other points remain the same.

The developing device 21 for black of this embodiment
0K 'is formed to be slightly larger, and the capacity of the toner is increased. The transfer fins are 251 ', 253'
There are two.

In general, among the four color toners, the consumption amount of the black toner is expected to be the largest. Therefore, it is desirable to increase the size of the black developing device 210K ′ as in this embodiment.

[0108]

EXAMPLES Hereinafter, more specific examples will be described.

The following description is based on the toner and the developing roller 21.
1. The specific configuration of the supply roller 240 and the regulating blade 260 will be described. In order to clarify the significance of the specific configuration or to facilitate understanding, first, the toner and the above-described configuration will be described. The development characteristics of the members are divided into transportability, supplyability, developing roller filming phenomenon, regulating blade filming phenomenon, development efficiency, sealability, fogging phenomenon, durability, hysteresis phenomenon, image unevenness, and difference in front and rear edge density. In addition to describing the effects of each of the above configurations on these properties and phenomena, etc., mentioning the hopper capacity and preservation that are considered important in configuring the developing device, and finally,
A description will be given of how the above specific configuration is made.

The basic structure of the toner of this embodiment is as follows.
A pigment, CCA (charge control agent), and a wax are bound with a synthetic resin, and a relatively large particle size external additive mainly for imparting durability and a fluid additive mainly for imparting fluidity to the surface thereof. It has a configuration in which an external additive having a relatively small particle diameter is attached.

Hereinafter, the development characteristics and the like will be sequentially described.

<Transportability> The transportability referred to here is the transportability of toner to the supply roller 240 by the transfer fins 251 or the like.

If the transportability is too high, the supply roller 240
In addition, excessive toner is supplied to the developing roller 211, so that the toner on the developing roller 211 cannot be regulated, and the toner overflows outside the developing device 210.

Conversely, if the transportability is poor, the supply roller 240
And the amount of toner supplied to the developing roller 211 is insufficient.
A desired image is not formed.

The transportability depends on the fluidity of the toner. In particular, when the amount of the external additive having a small particle size which affects the fluidity of the toner is 1.0% or more, good transportability can be obtained. However, when the amount exceeds 3.0%, the transportability is too high. I will.

A. D (loose apparent density)
It is desirably 0.30 g / cc or more.

<Supply Property> The supply property here refers to the ability to feed the toner from the supply roller 240 to the developing roller 211.

When the supply property is poor, image omission occurs in the cycle of the supply roller 240.

The supply property is determined by the properties of the toner and the supply roller 24.
0 and the configuration of the developing roller 211.

The flowability of the toner can be improved by adjusting the amount of the small particle size external additive to 1.0% or more, and the supply property can be improved. When the amount of the pigment is 15% or less,
By setting the amount of CA to 3% or less, the rise of charging can be improved, and the supply property can be improved.

The biting depth between the supply roller 240 and the developing roller 211 (the depth of the recess of the supply roller 240) is set to 0.1.
When the thickness is equal to or more than mm, the toner is sufficiently rubbed against the developing roller 211, so that the frictional charging of the toner is improved and the supply property is improved.

Further, the surface roughness of the developing roller 211 is set to R
When the thickness is at least 5 μm, the mechanical transport force can be improved, and good supply properties can be obtained.

These can improve the supply property even when used alone, but when combined, the supply property can be improved more effectively.

On the other hand, if the supply property is too high, the supply of toner to the developing roller 211 becomes excessive,
This makes it difficult to regulate the amount of toner on the upper surface of the developing device 210, and toner overflows outside the developing device 210. In particular, if the amount of the small particle size external additive of the toner exceeds 3.0%, the fluidity of the toner becomes too good, and the supply property becomes too high.

The developing amount (the amount of toner actually developed on the photoconductor 110) is 0.80 mg / cm ² or less.
The transport amount (the amount of toner on the developing roller 211 used for development) is 0.60 mg / cm ² or less, and the charge amount is −8.
It is desirable to be not more than μC / g.

<Developing Roller Filming Phenomenon> This phenomenon is a phenomenon in which toner fuses to the surface of the developing roller 211.

When filming of the developing roller occurs, a substantial portion of the image is missing or the image is shaded.

The developing roller filming is particularly affected by the supply of toner.

If the toner supply is poor, the developing roller 21
1, a portion having an extremely small amount of toner is formed, and the toner in that portion is regulated by the regulating blade 260 and the developing roller 21.
1 causes excessive stress, which causes a developing roller filming phenomenon.

Therefore, in order to improve the toner supply property, the amount of CCA is set to 3% or less, the amount of pigment is set to 15% or less, and the amount of the small particle size external additive is set to 1.5% or more. These can be effective alone, but can be further improved by combining them.

<Regulating Blade Filming Phenomenon> This phenomenon is a phenomenon in which the toner is fused to the regulating blade 260.

When this phenomenon occurs, a substantial portion of the image is lost (white stripes).

This phenomenon depends on the toner supply property and the state of the contact portion of the regulating blade 260 with the developing roller 211.

If the supply of toner is poor, the developing roller 21
1, a portion having an extremely small amount of toner is formed, and the toner in that portion is regulated by the regulating blade 260 and the developing roller 21.
1 causes excessive stress, thereby causing a regulating blade filming phenomenon.

Therefore, in order to improve the toner supply property, the amount of CCA is set to 3% or less, the amount of pigment is set to 15% or less, and the amount of the small particle size external additive is set to 1.5% or more. Further, Tg (glass transition point) is 55 ° C. or more, and Tm (melting temperature) is 11 ° C.
By setting the temperature to 0 ° C. or higher, the abrasion resistance of the toner can be improved and the filming phenomenon can be suppressed.

Further, the regulating blade 260 has a contact R with respect to the developing roller 211 (the radius of curvature (radius of the arc-shaped portion) of the contacting portion of the regulating blade 260 with the developing roller 211) is 100 μm or less, and the contact angle (regulating angle) Blade 26
0 is a developing roller 2 passing through a point where the developing roller 211 abuts.
Angle α formed by the tangent to 11 and regulating blade 260
(Refer to FIG. 6)) is set to 50 ° or more, so that the size of the space formed by the contact portion between the developing roller 211 and the regulating blade 260 is reduced by the toner on the developing roller 211 regulated by the regulating blade 260. Can return to the supply roller 240 side. If the size of this space is small, the toner will clog in this space and cause filming.

These are effective even when used alone, but can be further improved by combining them.

<Developing Efficiency> This is the ratio of the amount of toner actually used for developing the photoconductor 110 to the amount of toner carried to the developing position by the developing roller 211.

That is, the development efficiency is: development amount / (conveyance amount × ratio of peripheral speed of developing roller to photosensitive member) × 100 (%).

In order to improve the development efficiency, the amount of CCA should be 0.5% or more and the development amount should be 0.80 mg / cm ^2.
It is desirable to set the transport amount to 0.35 mg / cm ² or more.

<Sealability> The sealability here refers to the degree of leakage of toner from a toner seal provided on the end face and lower face of the developing roller 211 (the seal on the lower face is indicated by 275 in FIG. 3). is there.

[0142] Toner leakage leads to image defects in the image area, and causes contamination inside the apparatus even if it is outside the image area.

[0143] The sealing property is affected by the fluidity of the toner. When the fluidity of the toner is extremely high, the developing roller 2
The toner easily leaks from the gap between the toner seal 11 and the toner seal.

Therefore, it is desirable that the amount of the external additive having a small particle diameter which affects the fluidity of the toner is 3.0% or less.

Also, A.I. D is desirably 0.40 g / cc.

<Fogging Phenomenon> This phenomenon is a phenomenon in which toner adheres to a non-image portion (usually a white portion).

In the case of the reversal developing method using negatively charged toner,
As an example, the potential of the photoconductor is set to about -50 V in the image area, to about -600 V in the non-image area, and the developing bias is set to about -300 V.

Therefore, normally, the negatively charged toner does not adhere to the non-image portion. However, if the positively charged toner is on the developing roller, it adheres to the non-image portion. Further, when toner having a low charge amount is present, the binding force to the developing roller (adsorption force of the toner to the developing roller by electrostatic force or the like) is weak, and the toner may adhere to the photoreceptor by other forces.

Therefore, the fogging phenomenon can be reduced by making the charge polarity of the toner uniform and increasing the charge amount of the toner (decreasing the charge amount in the negatively charged toner).

In order to increase the charge amount of the toner, the transfer amount is reduced, the chance of contact between the toner and the charging member such as the regulating blade and the developing roller is increased, and the toner is frictionally charged.

It is desirable that the transport amount is 0.60 mg / cm ² or less and the charge amount is -8 μC / g or less. It is desirable that the supply roller has the same potential as the developing roller.

<Durability> Durability as used herein refers to the degree of image deterioration due to repeated image formation.

Image deterioration is caused by deterioration of the toner itself, filming of the toner, and abrasion of the regulating blade 260 and the like.

The supply property and the transfer property of the toner are deteriorated because the small particle size external additive adhering to the surface is buried in the resin.

Therefore, the amount of the small particle size external additive of the toner is set to 1.
By setting the amount of the large particle size external additive to 5% or more and the amount of the large particle size external additive to 0.5% or more, it is desirable to suppress the burial of the small particle size external additive. The type of the external additive having a large particle diameter is preferably silicon oil, and the particle diameter is desirably about 40 nm.

If the amount of CCA and the amount of pigment are large, filming is likely to occur and the durability is deteriorated. Therefore, it is preferable that the amount of CCA is 3% or less and the amount of pigment is 15% or less.

<History Phenomenon> This phenomenon is a phenomenon in which a pattern of an image formed earlier affects an image formed later.

[0158] The hysteresis phenomenon occurs when the rise of toner charge is poor. The rise of electrification depends on the CCA of the toner.
And the amount of external additives.

When the amount of CCA is 0.5% or more, the rise of charging is improved.

The effect of the CCA is more likely to be exhibited when the coverage of the external additive is lower, since the base particles into which the CCA is kneaded are more likely to come into direct contact with the charging member.

When a large amount of the small particle size external additive is attached,
While the effect of CCA becomes difficult to appear due to an increase in the coverage, when an external additive having a large particle size is used, the coverage is lower than that of a small particle size additive at the same weight ratio addition amount, so CCA
The effect becomes easy to come out.

On the other hand, if the amount of the external additive is small, the supply property is reduced.

Therefore, the amount of the large particle size external additive is desirably 1.5% or more and 5% or less, and the amount of the small particle size external additive is desirably 1.5% or more and 3% or less. .

The type having a large particle size was treated with silicone oil, and the type of the external additive having a small particle size was treated with HMDS (hexamethyldisilazane). The diameter of the external additive having a small particle diameter is about 40 nm,
It is desirable to set it to about nm.

It is desirable that the charge amount of the toner is such that the difference between the front and rear ends (described later) is 15 μC / g or less.

<Image Unevenness Phenomenon> This phenomenon is an attempt to form a uniform image, but the image becomes non-uniform.

This phenomenon is caused by the development roller, the supply roller, etc.
Occurs depending on the rotation period of the rotating body.

If the rotation of the rotating body is large, image unevenness is likely to occur. Therefore, it is preferable that the fluctuation of the developing roller with respect to the rotation center be 30 μm or less, and that of the supply roller be 150 μm or less with respect to the rotation center. .

Further, the pipe used as the developing roller
The roughness of the underlayer before adjusting the surface roughness is Rmax1 μm
If the ratio exceeds the limit, it is difficult to make the surface roughness uniform in the subsequent processing, and image unevenness is likely to occur. Therefore, it is desirable that the roughness of the base of the pipe be 1 μm or less Rmax.

Furthermore, if the material of the shaft that forms the rotation center of the developing roller is weak, the amount of bending due to external force during rotation increases, so that the material of the shaft is preferably iron.

<Difference in Leading Edge Density> This phenomenon is a phenomenon in which, when a solid image is formed, the density (development amount) differs between the leading end portion of the image and the other trailing end portion.

This phenomenon is caused by the fact that the charge amount and the transport amount of the toner on the developing roller corresponding to the front end portion and the other rear end portion are different, and as a result, the development amounts at the front end and the rear end are different. Occur.

This phenomenon can be suppressed by setting the difference in toner transport amount between the front end and the rear end within 0.15 mg / cm ² and the difference in charge amount within 15 μC / g. Further, the difference in the amount of development can be suppressed by keeping the difference within 0.15 mg / cm ² . The developing roller has a linear velocity of 300 mm / s or more and a regulated load of 50 g / cm.
In the following, in order to reduce the difference in the amount of toner transport, it is necessary to bring the regulating blade into edge contact. If the regulating blade makes surface contact including the front and rear surfaces of the ridge line, the difference in the transport amount increases. In order to prevent contact with the regulating blade screen, the contact angle is set to 50 ° or more and 85 ° or less.

It is desirable that the amount of CCA in the toner is 0.5% or more.

<Hopper Capacity> This is the capacity of toner in the developing device case necessary to form a predetermined number of images.

High density toner (toner containing a large amount of pigment)
By using the toner, a desired image density can be secured even with a small amount of toner. Therefore, by using high-density toner, the hopper capacity can be reduced while image density is secured, and the developing device 210 can be made compact.

The amount of the pigment is desirably 5% or more.

<Preservability> The degree of deterioration of the above-mentioned various properties when the apparatus is not operating, such as the transport environment and the preservation environment.

This deterioration is caused by so-called blocking in which the toner hardens in the developing device.

By setting the Tg of the toner to 55 ° C. or higher, blocking can be prevented.

Although the development characteristics and the like have been mainly described above, based on the above-described circumstances, finally, what specific configurations of the toner, the development roller 211, the supply roller 240, and the regulating blade 260 have been made. Will be described below.

<Regarding Toner> As described above, the toner is formed by binding pigment, CCA (charge control agent) and wax with a synthetic resin, and has a relatively large diameter mainly for imparting durability to the surface thereof. And an external additive having a relatively small diameter for mainly imparting fluidity.

In this example, these compositional elements and characteristics were as follows.

(1) Synthetic resin The synthetic resin was polyester for improving the fixing property.

(2) Pigment The amount of the pigment was 5% or more and 15% or less. As described above, the purpose is to reduce the hopper capacity while securing the image density, and to make the developing device 210 compact. On the other hand, if the amount of the pigment is less than 5%, the saturation of the color image is reduced. If the amount is more than 15%, the supply property is reduced, and the developing roller filming and the blade filming are likely to occur. Because it becomes.

(3) CCA The amount of CCA was 0.5% or more and 3% or less. The reason is as described above. On the other hand, if the amount of CCA exceeds 3%, the transferability decreases.

(4) Wax The amount of wax was 0.5% or more. This is to improve the releasability of the toner from the fixing roller. Also,
This is also to increase the fixing strength of the toner to a recording medium such as paper.

(5) External additive having a relatively large diameter The external additive having a large diameter is silicon oil, and the particle diameter is 40 n.
m, and the amount was 0.5% or more and 5% or less. The reason is as described above.

(6) External additive having a relatively small diameter The external additive having a small diameter was HMDS, its particle size was about 14 nm, and its amount was 1.0% or more and 3% or less. The reason is as described above. Also, if the addition amount is 3% or more, the fixability decreases. In order to improve the transferability, it is desirable that the amount of addition is 1.5% or more.

(7) Particle Size The particle size of the toner is not less than 6 μm and not more than 9 μm. 6μ
If it is less than m, the cleaning property is reduced and the cost is high. Conversely, if the thickness is 9 μm or more, the resolution is reduced.

Note that the particle size distribution of the toner used this time is shown in FIG.
It was shown to. The particle size distribution of the toner was measured using a Coulter counter model TA-II. The aperture diameter is 100 μm, and the electrolyte is ISOTON-II
Was used.

In the table shown in FIG. 9A, the number is shown in the right column.
The left column shows the volume, the lower row shows the measurement results, and the upper row shows the calculated values based on the measurement results. In addition,
"Volume" is the volume when the measured toner particles are considered to be spheres.

In the graphs shown in FIGS. 9B and 9C,
The bar graph shows the number data, and the line graph shows the accumulated data.

In the table shown in FIG. 9A, the meanings of the items indicating the measurement results in the lower row are as follows. DIF N: This is the most basic data, and indicates the number data (the number data of toner) input from the I / O for each channel. DIF%: The above number data (DIF N) is displayed in% for each channel. CUM N: The above number data (DIF N) is accumulated and displayed. CUM%: The above DIF% is accumulated and displayed.

The meanings of the items indicating the calculated values in the upper row are as follows. 25.4 μ ↑: The cumulative% value of those having a value of 25.4 μm or more is displayed. 6.35 μ ↓: The cumulative% value of those having a diameter of 6.35 μm or less is displayed. KURTOSIS: Kurtosis (sharpness) of the distribution. SKEWNESS: Represents the skewness of the distribution. Average: The arithmetic average particle diameter is displayed. 25%: The value of the particle size when the cumulative% reaches 25% (see the graphs of FIGS. 9B and 9C). 50%: The value of the particle size when the cumulative% reaches 50%. 75%: The value of the particle diameter when the cumulative% reaches 75% (see the graphs of FIGS. 9 (b) and (c)). CV %: Coefficient of variation (%). SDμ: Standard deviation (μm).

(8) A. DA. D was 0.30 g / cc or more and 0.40 g / cc or less. The reason is as described above. Also, when the content is in this range, good transferability can be obtained. The cleaning property is also improved by setting the content to 0.40 g / cc or less.

(9) Coverage of External Additive The coverage of the external additive is 100% or more, that is, an amount that can cover substantially the entire surface of the toner particles with the external additive (in terms of the projected area). It was decided to add it.

(10) Tg Tg was 55 ° C. or higher. The reason is as described above.

(11) Tm Tm was set at 110 ° C. or more and 130 ° C. or less. The reason is as described above. On the other hand, when the temperature is 130 ° C. or more, the fixing property is deteriorated.

(12) Molecular Weight Distribution The molecular weight distribution (MW / MN) was set to 100 or more. 10
This is because if it is 0 or less, the fixing property is reduced.

(13) Developed amount The developed amount was 0.40 mg / cm ² or more and 0.80 mg / cm ² or more.
cm ² or less, and the difference between the leading and trailing edges was within 0.15 mg / cm ² . The reason is as described above. Also, 0.40
When the amount is less than 0.8 mg / cm ² , the image density decreases. On the other hand, when the amount is 0.80 mg / cm ² or more, the transferability decreases.

(14) Carry amount The carry amount is 0.35 mg / cm ² or more and 0.60 mg / cm ²
cm ² or less, and the difference between the leading and trailing edges was within 0.15 mg / cm ² . The reason is as described above.

(15) Charge Amount The charge amount was not less than -35 μC / g and not more than -8 μC / g. The reason for setting to -8 μC / g or less is as described above. On the other hand, if it is -35 [mu] C / g or less, the transferability is reduced.

<Regarding the Developing Roller> (1) The shaft material was iron and the diameter was 5 mm.

(2) The surface roughness of the flange end surface (the end surface (side surface) of the developing roller) was set to Rmax 0.5 μm or less. This is for improving the sealing property.

(3) The corner of the developing roller (the corner between the cylindrical surface and the end surface (side surface)) was chamfered with an R, and the R was 0.1 mm or more. This is to prevent the photoconductor 110 from being damaged at the corners.

(4) The surface roughness is Rz 5 μm or more,
It was 10 μm or less. This is because when Rz is 5 μm or less, the supply of toner is reduced, and when Rz is 10 μm or more, the resolution of an image is reduced.

(5) The deflection was 30 μm or less. The reason is as described above. Also, if the shake is 30 μm or more, the supply of the toner is also reduced.

(6) The outer diameter tolerance was about ± 0.02 mm. This is to ensure supplyability and to prevent image unevenness.

<Regarding the Supply Roller> (1) The shaft material was iron and the diameter was 5 mm. This is to prevent image unevenness.

(2) The run-out was set to 150 μm or less. This is to prevent image unevenness.

(3) The outer diameter tolerance was about ± 0.15 mm. This is to ensure supplyability and to prevent image unevenness.

(4) The hardness was 40 ° or more and 70 ° or less. If the angle is 40 ° or less, the supply property decreases, and if the angle is 70 ° or more, the driving torque increases.

(5) The open cell rate was 30 to 80%. This is to ensure supply.

(6) The polishing direction was a forward direction (relative to the rotation direction of the supply roller). This is to ensure supply.

(7) The peripheral speed ratio with respect to the developing roller 211 is about 50% to 80%, more preferably 60% to 70%, and specifically about 64%. If it is less than 50%, the toner supply to the developing roller cannot be ensured, and if it is more than 80%, the toner is deteriorated and the driving torque increases.

(8) The bite depth (the amount of depression at the contact portion with the developing roller) was set to 0.1 mm or more and 0.4 mm or less. If the thickness is 0.1 mm or less, the toner is not sufficiently rubbed against the developing roller, and if the thickness is 0.4 mm or more, the driving torque increases.

(9) The potential was the same as that of the developing roller.
This is to prevent fogging and history.

<Regarding the Regulation Blade> (1) The abutment R on the developing roller 211 was 30 μm or more and 150 μm or less. The reason for setting it to 30 μm or more is
This is to prevent the necessary toner conveyance amount from being secured.
The reason why the thickness is set to 0 μm or less is to reduce the difference between the front and rear edge density.

(2) The contact angle with the developing roller 211 is 5
0 ° or more and 85 ° or less. It is more than 50 °
The reason why the filming is prevented and the reason why the angle is 85 ° or less is to reduce the difference between the front and rear end density.

(3) Straightness was set to 30 μm or less. This is to reduce the image unevenness (the entire image, particularly the unevenness of light and shade generated in the width direction).

(4) The surface roughness was set to Rz 15 μm or less. This is to reduce uneven streaks (fine streak-like image unevenness, in particular, unevenness in which an image is missing in a line parallel to the paper transport direction).

Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described embodiments or examples, and may be appropriately modified within the scope of the present invention. It is.

[0224]

According to the developing device of the first aspect, the photosensitive member is not flawed by the end of the toner conveying surface of the developing roller, and the sealing property is improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus using a developing device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of four developing units 210, a photoreceptor 110, and the periphery thereof.

FIG. 3 is an enlarged view of a developing unit 210M.

FIG. 4 is a sectional view taken along a line IV-IV in FIG. 3;

5A is an enlarged cross-sectional view taken along a line VV in FIG. 3, and FIG. 5B is a view taken in the direction of arrow b in FIG.

FIG. 6 is an operation explanatory view.

FIG. 7 is an operation explanatory view.

FIG. 8 is a schematic diagram showing a main part of an image forming apparatus using a developing device according to a second embodiment of the invention.

9A and 9B are diagrams illustrating the particle size distribution of the toner, in which FIG. 9A is a table showing the particle size distribution, and FIGS. 9B and 9C are graphs each showing the particle size distribution.

[Explanation of symbols]

 T toner 210 developing device 211 developing roller 211 212 shaft 230 case 240 supply roller 241 shaft 244 corner 270 seal member SE seal member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoichi Yamada 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Taihei Ishiwata 3-35-5, Yamato, Suwa-shi, Nagano Seiko-Epson (72) Inventor Hidenori Kim 3-5-5 Yamato, Suwa-shi, Nagano Prefecture Seiko Epson Corporation

Claims (1)

[Claims] 1. A case containing a toner, a developing roller rotatably supported on the case by a shaft, a regulating blade for regulating an amount of toner on the developing roller, and a side end of the developing roller. A seal member for preventing the toner from leaking out of the case from the shaft portion, wherein an end portion of the toner conveying surface of the developing roller is chamfered, and an elastic displacement of the seal member is provided. A developing device wherein the amount is larger than the chamfer amount.