JPS6215574A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a developer from a developing device on an undriven side from sticking on a photosensitive drum without rotating a magnet roller at every time by putting a developing device on a selected driven side closer to an image carrier and moving the developing device on the undriven side away from the image carrier. CONSTITUTION:The 2nd developing device 7 moves away from the photosensitive drum 4 and an interlocking cam 77 further rotates after the photosensitive drum 4 rotates by a specific angle, so that a projection 82 moves to the arrangement part of a rotary roller 87. The projection 82 presses the rotary roller 87 and then the developing roller 31 of the 1st developing device 6 comes close to the photosensitive drum 4 and faces it, so that development is carried out by a magnetic brush B. Further, when the 2nd developing device 7 is selected and switched from the driving state of the 1st developing device 6, the 2nd developing device 7 is arranged behind the 1st developing device 6 in the rotating direction of the photosenstive drum 4, so even if toner Da from the 1st developing device 7 sticks on the photosensitive drum 4 unnecessarily, it is never mixed with the toner Da in the 2nd developing device and the photosensitive drum 4 need not be rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention is directed to
Regarding equipment.

[Technical disadvantages of inventions and their problems]

This type of developing device is provided with two types of developing devices facing the photoreceptor drum (image carrier), that is, a developing device containing, for example, a red developer and a developing device containing a black developer. According to a selection switching operation by an operator, one of the developing devices is driven to perform a predetermined development. Each developing device is provided with a developing roller, and this developing roller is equipped with a magnet [1] having a plurality of magnetic poles.
- A rotating sleeve is rotatably fitted on the outer periphery of the rotating sleeve, and a magnetic brush is formed on the outer periphery of the rotating sleeve IL' by the action of the magnetic pole, and a predetermined development process is carried out via this magnetic brush. In addition, a leveler that eliminates the magnetic brush is provided in the developing device, and the rotation of the magnet roller is controlled so that one magnetic pole of the magnet roller faces this leveler when not developing. In other words, when one of the developing units is selected from the current-standby state, the rotation of the magnetic roller is first controlled so that one magnetic pole moves away from the leveler and the other magnetic pole faces the photosensitive drum. Based on this, a magnetic brush of developer is formed on the outer periphery of the rotating sleeve, and in this state, the rotating sleeve rotates to perform 1q image. At this time, the other developing device is In this case, one magnetic pole is set to face the leveler by the rotation of magnets 1 to ○-ra, and with this setting, the magnetic brush disappears,
This causes this other .

This is designed to prevent the developer in the developing device from accidentally adhering to the photoreceptor drum. Then, when the other developer is selected, a magnetic brush is similarly formed and development is performed, and the magnetic brush of the other developer disappears.

However, in the conventional method, each time development is
It is necessary to rotate the magnetic 1-roller of the developing device on the non-driving side to eliminate the magnetic brush one by one, which results in a complicated configuration and a female point that is expensive and large.

[Purpose of the invention]

The present invention has been made with attention to these points, and its purpose is to transfer the developer of the non-drive side developing device to the photoreceptor drum (image bearing drum) without rotating the magnetic i-roller every time. It is an object of the present invention to provide a developing device that can reliably prevent adhesion to the body.

[Summary of the invention]

That is, in the present invention, the first and second
A developing device is provided, and one of the developing devices is selectively driven to edge the latent image on the image carrier with the developer of the developing device. Place the second developing device - Image 1 (installed movably in the direction toward and away from the special holiday), move the selected developing device on the driving side close to the image carrier, and place the developing device on the non-driving side is retracted from the image carrier.

[Embodiments of the invention]

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

In the figure, reference numeral 1 denotes the main body of a two-color color copying machine. On the upper part of the main body 1, a document table 2 is mounted. On the lower side of the document table 2, a light source 3a such as a lamp, which constitutes an exposure optical device 3, and mirrors M1 to M6, lens 3b, etc. are iiQ IJ.

Further, a photoreceptor drum 4 is rotatably provided as an image carrier approximately in the center of the main body 1, and around the photoreceptor drum 4, a charging device 5 is provided, and a first and a second charger for two-color development are provided. Further, a transfer device 8, a cleaning device 9, a static eliminator 10, etc. are provided.

On one side of the lower part of the main body 1, a covering part is provided on the lower side of the outer periphery of the photosensitive drum 4 in synchronization with the 40 rotations of the photosensitive drum.
A paper feeding device 11 is provided for supplying copy paper P, which is a copying member, and a conveyor belt 12 is provided on the other side, and a fixing device 13 is provided at the conveying side/internal light end of the conveyor belts 1 to 12.
However, further ahead there is a pair of paper ejection rollers 14 and the main body 1.
A paper discharge tray 15 is provided protruding from the outside of each of the paper sheets.

Note that 16 is a cooling fan that cools the inside of the main body 1.

As the photosensitive drum 4 rotates, it is first uniformly charged by the charging device 3. On the other hand, the light source 3a of the exposure optical device 3 moves integrally with the mirror M1 to scan the image of the document placed on the document table 2 in synchronization with the rotation of the photosensitive drum 4. (to scan. The reflected light of this image passes through the lens 3b and the mirrors M4 to M6 while keeping the optical path length constant based on the movement of the mirrors M2 and M3. The electrostatic latent image is introduced onto the surface of the photoreceptor drum 4, thereby forming an electrostatic latent image on the surface of the photoreceptor drum 4.

Thereafter, the developer is conveyed and supplied to the surface of the photoreceptor drum 4 by either one of the selected developing devices 6 or 7, and predetermined development is performed, so that an electrostatic latent image on the photoreceptor drum 4 is formed. Visualized.

In this state, the rotation of the photoreceptor drum 4 further progresses, and in synchronization with this, the image (toner image) on the photoreceptor drum 4 is transferred to the copy paper P fed from the paper feeder 11 by the operation of the transfer device 8. be done. The copy paper P on which the image has been transferred in this way is separated from the surface of the photoreceptor drum 4 and sent to the fixing device 13 by the conveyor bells 1 to 12, where the image is fixed, and then the copy paper P is transferred from the paper ejection roller 14t. The paper is delivered to the paper discharge tray 15.

On the other hand, the photosensitive drum 4 after both edges have been transferred to the copy paper P is cleaned to remove residual developer by the cleaning device 9, and is roughly neutralized by the static eliminator 10 so that the potential is lowered to a constant level. and prepares for the next copying operation.

The paper feeding device 11 in such a two-color copying machine is constructed as follows. That is, cassette storage sections 20a and 20b are provided in upper and lower two stages in the lower part of one end side in the main body 1, and each of these cassette storage sections 20a and 20b has a paper feed cassette 218 that stores paper sizes of 15, A4, etc.
．． 21b is removably set, and automatic paper feeding rollers 22a and 22b are rotatably provided above each of these paper feeding cassettes 21a and 21b to constitute an automatic paper feeding section. A manual paper feed slot 23 is provided above the automatic paper feed section, and a manual paper feed roller 24 is provided inside the slot.
is rotatably provided. Note that the automatic paper feed row 522a of the paper feed cassette 21a on the upper stage side of the upper automatic paper feed section
is retracted above the manual paper feed roller 24 except during paper feeding operation. Furthermore, a pair of transport rollers 25 which also serve as manual paper feed are rotatably provided at the back of the set position of the upper paper feed cassette 21a, and also rotatably provided at the back of the set position of the lower paper feed cassette 21b. A pair of conveyor rollers 26
is rotatably provided. Further inward of each pair of transport rollers 25, 26 are plate-shaped transport guides 27a, 27b, 27c/fi that constitute the transport path 27.
A pair of resist rollers 11-28 are rotatably provided at the inner end of the conveyance path 27, and are connected to the resist row 52n and under the outer periphery of the photoreceptor drum 4. A conveyance guide 29 is provided between the side transfer site and the side transfer site.

In such a paper feeding device 11, the paper feed roller (one of 22a, 22b, 24) corresponding to the paper size selection by the operator, selection of automatic or manual paper feeding, etc. Perform the action. For example, when B5 size is selected, the upper automatic paper feed roller 22a descends and rotates, and the 85 size copy paper P in the upper paper feed cassette 2ia is fed out sheet by sheet from the top layer, and the conveyance roller Send it in 25 minutes. Also, if you select A4 size,
The lower automatic paper feed roller 22b rotates, and the A4 size copy sheets P in the lower paper feed cassette 2Ib are fed out one by one from the top layer and sent between the transport rollers 26. On the other hand, in the case of manual paper feed, the manual paper feed roller 24 rotates and feeds the copy paper P inserted from the manual paper feed slot 23 between the conveyance rollers 25 .

[Feeded in this way] Bee paper P is conveyed to the conveyance path 27 by the rotation of the conveyance rollers 25 or 26, and guided by the conveyance guides 27a and 27b1 or 27b and 27c to reach the registration rollers 28.
8, the photoreceptor drum 4 is temporarily aligned and guided by the conveyance guide 29 at a timing synchronized with the rotation of the photoreceptor drum 4, and sent to the transfer section on the lower side of the outer circumference of the photoreceptor drum 4.

The first and second developing units 6 and 7' are each provided with a developing roller 31 in a casing 30, and the casing 30 of the first developing unit 6 disposed on the lower stage side contains, for example, a black developer 1). a is also the second developing device 7 located on the upper stage side.
The casings 30 each contain, for example, a red developer nb, which is a two-component developer. Each developing roller 31 is connected to a magnetic roller 53 installed between both side walls of the casing 30, as shown in FIGS. 2 and 3.
2, and a rotating sleeve 33 that fits around the outer periphery of the magnet roller 32 and is rotatably supported with respect to the magnet roller 32. The magnet roller 32 has a plurality of magnetic poles 36 attached to the outer peripheral side of the shaft 34 via a holder 35 so as to face the rotating sleeve 33. developer r)a(f)b) on the outer peripheral surface of
A magnetic brush is formed. One end of the L shaft 34 passes through one side wall of the casing 30, and as shown in FIGS.
It is non-rotatably supported by a support plate 38 attached to the outer surface of the casing 30 by removing screws 37, and the other end is fixed to the other side wall of the casing 30 via screws 39.゛The rotating sleeve 33 is rotatably supported via the upper two shafts 34, and has a protruding tube 40 on one end surface, and this protruding tube 40 fits around the outer periphery of the shaft 34 and passes through one side wall of the casing 30. , a fitting carrier 41 is attached to the penetrating end thereof.

As shown in FIG.
．． 46.47, and frames 1148.48 are arranged on both end sides of the casing 30.30, and these frames 4
Opened on 8.48 IT149.

49 are formed, and the casing 3 is inserted into these openings 49 and 49.
('), both ends of 30 are loosely connected. frame 443
．． Each of the guide holes 48 has a long guide hole 50, and guide holes 51, 52, 53, and 54 are attached thereto. One end of the upper two shafts 34 protruding from one end surface of the casing 30.30, and pins 45.45.degree. ,
! They are slidably fitted into guide holes 50 of 52, 53° and 54, respectively. Also adjacent to each frame 48.48 are levers 60.61.62. ．． 63, and these levers 60, 61, 62, 63 are provided with links 64, 65, 66, 67 connected to rotation ports (t).

The phase η of the levers 60, 62 and 61, 63 are each connected to a drive shaft 68,6 fl, and the synchronized movement of these drive shafts 68,68, e) link 64. .66 and 65.67 are designed to reciprocate each other. The name link f'+4... is shown in FIGS. A sliding hole 70 is formed along the direction, and a holding hole 71 is formed on the side surface C of the frame 48 corresponding to this sliding hole 70. and the kite bushing 72 is slidably fitted into the support hole 71,
(-The 1000-F bushing 72 is elastically biased by the spring 73 toward the tip side of the sliding hole 70.
,・51;Two-person link 64. ．． 65.66, fi7f] 1 f and 172... are provided, and these guide pushers] 72... are provided with bins 45.45. 47.47 is in it.

The interlocking arms 75.76 are attached to the l2R self-drive single shaft 68.68, and these interlocking arms 75.
An interlocking cam 77 is arranged opposite to 76 by 1QfJ. A gear 78 is attached to this interlocking force 1177, and an output shaft 80 of a motor 79 meshes with this gear 78. The interlocking cam 77 has a cam body 83 formed by integrally protruding a protrusion 82 from a part of the circumferential surface of a disk, and a cam body 84 arranged along the circumferential surface of the cam body 83 to form a shape @84 therebetween. It is composed of guide walls 8 and 5. A detection switch 86 is installed on the outer side of the guide wall 85. A rotary roller 87.88 is provided at one end of the interlocking arm 75.76, and these rotary rollers 8.7.8. ．． 8 are fitted in the tenth groove 84 at regular intervals, respectively, so that they can be moved freely.

In addition, inside the casing 30 of each developing device 6.7, a developer agitator 90, a scraper 91 for scraping off the developer,
A replenishment roller 92 is provided for replenishing the toner.

Therefore, during the standby period of the developing operation, as shown in FIG.
31 are respectively retracted from the photoreceptor drum 4, and a relatively large gap 1.12 is maintained between the photoreceptor drums 4 and 4.
is facing [). At this time, each pin 46.46 of the developing device 6.7, shirts 1 to 34.34, and each guide 5
1.52.53° 54 There is a play δ of only 2 mm between the rear end edge of the guide hole 50, and each guide bush 72 has a spring 73. The protrusion 81182 of the interlocking cam is held in contact with the tip edge of the sliding hole 70 by the urging force of the rotating roller 87.
It is facing away from 88. In this state, when a selection operation is performed on the first developing device 6 by the A-pellator, the motor 79 is started, the interlocking cam 77 is rotated, and the first developing device 6 is selected.
As shown in FIG. 2, the rotation port 87 is pressed by the protrusion 82, and the rotation of the interlocking cam 77 is stopped at this suppressed position. Rotation [In response to the pressure on J-ra 87, the interlocking arm 75 moves II! This movement is transmitted to the links 64 and 66 via the drive shaft 68 and the lever 60°-14=62, and these links 64 and 66 move toward the photoreceptor to the 40ν cocoon side. The slide δa of the movement of the links 64 and 66 is expressed as follows: h is the protruding height of the protrusion 82 of the interlocking cam 77, al is the quality of the interlocking arm 75, and e2 is the quality of the levers 6(') and 62. Then, δa: (ml, /l')h. Due to such movement of the links 64 and 66, the first developing device 6 moves to the side where the photosensitive drum 4 is disposed, and the shirt]-34 and the bin 4 are moved.
6 comes into contact with the leading edge of the guide hole 50, 50, and the developing roller 31 approaches the photosensitive drum 4. The links 64 and 66 connect the shirts 1 to 34 of the developing device 6 and the bottle 46 to the guide hole 5.
0.50's tip edge (J), the movement continues in one step, and this action causes the guide bushes 7.2', 72
is stopped together with the developer 6'! Link 64.6 with
6 is a spring 73:, the guide bush 7 is compressed against the spring 73, that is, the spring 73 is compressed.
2.72, and as a result the evacuation hole 70.70
There is a gap δb between the tip edge of the guide bush 72 and 72.
is formed.

That is, the link 64.6 ("i's movement l-n-ri δ
There is a gap between δa and the stroke δC of movement of the developing device 6.
〉There is a relationship of δC, and based on this, spring 73
y 73 is compressed, and the shaft 34 and bottle 46 of the developing device 6 are pressed by the elastic force of these springs 73.
Thereby, the positioning of the developing device 6 is ensured, and the IM image roller 31 faces the circumferential surface of the photosensitive drum 4 in close proximity with a predetermined width.

In this state, the toner Da formed on the outer peripheral surface of the rotating sleeve 33 due to the action of the magnet 1 to the roller 32
The electrostatic latent image on the photosensitive drum 4 is developed by the magnetic brush 8 as the rotating sleeve 33 rotates, and the pA
Imaged. At this time, the developing roller 31 of the second developing device 7
is retracted at a large distance from the photoreceptor drum 4, so that the developer 6b on the developing row 531 does not inadvertently adhere to the photoreceptor drum 4.
Accurate development can be performed using the developing device 6.

On the other hand, when the second developing device 7 is selected by the operator, the motor 79 is activated and the interlocking cam 77 is rotated.
As shown in the figure, the protrusion 82 is removed from the rotating roller 87 by one step, and comes into contact with and presses the other rotating roller 88, and the interlocking cam foot stops rotating at this suppressed position. ll1ll of the protrusion 82 relative to the rotating row 587
As the roller 87 is removed, the rotating roller 87 is forcibly pulled by the copying member 84, and the interlocking arm 75 rotates counterclockwise, and this operation separates the first developing device 6 from the photosensitive drum 4. Move in the direction and evacuate. Further, as the protrusion 82 presses the rotation 0-ra 88, the interlocking arm 76 rotates clockwise, and this movement causes the drive shaft 68 and the lever 6 to rotate.
1.63 to the links 65 and 67, and these links 65 and '67 move to the side where the photosensitive drum 4 is arranged. And, by moving these links 64 and 66,
The second developing device 7 moves to the side where the photosensitive drum 4 is disposed, and the shaft 34 and the bottle 46 are moved to the tip 1 of the guide hole 50.50.
7 and the developing roller 531 approaches the photosensitive drum 4 . At this time, as in the case of the first developing device 6, the links 65 and 67 continue to move (φ) even after the shaft 34 and the bottle 46 of the developing device 7 come into contact with the leading edges of the guide holes 50:50. This action causes the spring 73.7 to
3 is compressed, and the elastic force of these springs 73, 73 causes the shaft 34 and the dowel 46 of the developing device 7 to move into the guide hole 50.
The developing roller 3
1 faces the circumferential surface of the photoreceptor drum 4 in close proximity with a predetermined width. Then, the electrostatic latent image on the photosensitive drum 4 is developed by the magnetic brush 0 using the toner 0'b on the outer circumferential surface of the rotating sleeve 33, and becomes a visible image. At this time, since the developing roller 31 of the first developing device 6 is retracted by a large distance from the photosensitive drum 4, the developer Da on this developing roller 31 may inadvertently adhere to the photosensitive drum 4. Therefore, the second developing device 7 can perform accurate development. 'Furthermore, when the operator selects the first developing device 6 again from this state, the rotation of the interlocking cam 77 causes the
The protrusion 82 separates from the rotating roller 88, and this operation causes the second
The developing device 7 moves in the direction away from the photoreceptor drum 4, and both the first and second developing devices 6.7 -B,
It is held at a position where it is retracted from the photosensitive drum 4. Under this condition, the photosensitive drum 4 rotates clockwise by a certain angle. This is to prevent the toner Db that has unnecessarily adhered onto the photoreceptor drum 4 from being mixed into the toner 1)a of the first developing device 6. That is, when the developing roller 31 of the second developing device 7 is disposed close to the photoreceptor drum 4, the toner Db unnecessarily adheres to the portion a of the photoreceptor drum 4 that faces the developing roller 31. Therefore, depending on the selection of the developing device 6, the second
If the developing device 7 is retracted and the first developing device 6 is brought close to the photoreceptor drum 4 in this state, the photoreceptor drum 4 will rotate and the portion a will become the developing roller of the first developing device 6. 31
1 to 1 of the second developing device 7 when moving to a position facing the
There is a possibility that the toner 11b may be mixed into the toner Da of the first developing device 6. Therefore, after retracting the second developing device 7, the photosensitive drum 4 is rotated by a certain angle, that is, an angle θ or more until the part a passes the part facing the first developing device 6. . Note that the toner nb unnecessarily attached to the photoreceptor drum 4 is removed by the cleaning device 9 during the above-mentioned rotation or the subsequent rotation of the rotary drum 4.

After the second developing device 7 is retracted from the photoreceptor drum 4 and the photoreceptor drum 4 has rotated by a certain angle, the interlocking cam 77 further rotates, and the protrusion 82 moves toward the rotating roller 87.
The protrusion 82 moves the rotating roller 8
7 is pressed, and in response to this, the developing roller 31 of the first developing device 6 approaches and opposes the photosensitive drum 4 in the same manner as described above, and the magnetic brush B of this developing roller 31 performs development.

Note that when the second developing device 7 is selected and switched from the driving state of the first developing device 6, the second developing device 7 is in the same position as the first developing device with respect to the rotational direction of the photosensitive drum 40. 6, even if the toner 1) a of the first developing device 7 unnecessarily adheres to the photosensitive drum 4, it will be transferred to the toner [) a of the second developing device 7. There is no risk of contamination, and therefore there is no need to apply the above-mentioned rotation to the photosensitive drum 4.

As described above, each developing device 6.7 is placed in a predetermined operating position by rotating the interlocking cam 77 by a predetermined angle, and the rotation angle of the interlocking cam 77 is detected by the detection switch 86. Interlocking cam 77 based on detection
rotation is controlled.

Further, each interlocking cam 77 is provided with a rotating roller 87 that is linked to the first developing device 6 and a rotating roller 88 that is linked to the second developing device 7. Since the developing units 6 and 7 are operated at the same time, there is no time wastage, and the output of the motor 79 is reduced, which has the advantage of improving efficiency.

〔Effect of the invention〕

As explained above, according to the present invention, when one developing mold is driven to perform development, the other developing device on the non-driven side is retracted from the image carrier, so the magnetic roller is rotated one by one. It is possible to reliably prevent the developer from accidentally adhering to the image bearing member without any rotational drive mechanism for the magnet roller.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of a two-color copying machine, FIG. 2 is a cross-sectional view of a developing roller,
FIG. 3 is a longitudinal sectional view, FIG. 4 is a front view of the support portion of the shaft of the magnet roller, and FIG. 5 is a perspective view.
Fig. 6 is an exploded perspective view of the interlocking mechanism of the developing unit, Fig. 7 is a cross-sectional view of the support part of the link, Fig. 8 is a front view of the same, Fig. 9 is a front view of the interlocking cam, and Fig. 10 is a cross-section of the same. Figure, 11th
12 and 13 are cross-sectional views sequentially showing the moving states of the developing device. 4... Photosensitive drum (image carrier) 6.7... Developing device. Applicant's agent Patent attorney Takehiko Suzue Figure 8 Figure 10

Claims (1)

[Claims] First and second developing devices are provided opposite to the image carrier, and one of these developing devices is selectively driven to develop the latent image on the image carrier with the developer of the developing device. The first and second developing units are provided movably in directions toward and away from the image carrier, and the selected driving side developing unit is brought close to the image carrier, and the non-driving side developing unit is moved toward and away from the image carrier. A developing device characterized by retracting a container from an image carrier.