JPS60229042A - Developing device - Google Patents

Abstract

PURPOSE:To perform easily and securely development in plural colors with small-sized constitution by interposing a magnetic shield member between the 1st and the 2nd developing body equipped with a magnetic roll. CONSTITUTION:The developing device 10 drives the developing roller 50 of the 1st developing body and the developing roller 51 of the 2nd developing body selectively to take a color copy of black or one of other colors, e.g. red, yellow, blue, green, etc. Then the device is divided into two, i.e. the 1st developing unit 52 including the developing roller 50 and the 2nd developing unit 53 including the developing roller 51; a black developer with a high frequency of use is used by the 2nd developing unit 53 as a lower stage and a color developer is used by the 1st developing unit 52 as an upper stage. A magnetic plate 140 made of iron is provided as the magnetic shield member between the developing roll 50 and developing roll 51 to reduce the influence of the magnetic flux density and pole distribution upon other magnetic rolls 64 and 64'. Consequently, the constitution is reduced in size, but development is carried out in plural colors easily and securely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a developing device that can be applied to, for example, a two-color color copying machine.

[Technical background of the invention and one point in between]

In recent years, the use of color in a-photo cameras has progressed, and colors other than black have been introduced! 1ltjj! Two-color color copying machines and the like have been put into practical use.

However, in conventional two-color color copying machines, a plurality of cartridges, each of which integrates a developing device and a photoreceptor, are prepared and selectively replaced, making the operation extremely troublesome. There was such a problem.

Therefore, the present inventors have developed a two-color dust imaging device that can perform a 'yL image by selectively driving the first developing body and the second developing body by an operator's button switching operation, etc. It is progressing.

However, this species! In the jl image device.

When a first developer and a second developer with magnetic rolls are disposed close to each other, the magnetic flux density and polar distribution of these magnetic rolls will shadow each other, resulting in a good developer magnetic brush. There is a serious problem that formation cannot be performed and good developing operation cannot be obtained. However, if the second developing body is separated, the device will be too large to be put to practical use.

[Purpose of the invention]

The present invention has been made based on the above circumstances.

The purpose is to provide a developing device that can easily and reliably develop a plurality of colors even though it has a small configuration.

[Summary of the invention]

In order to achieve the above object, the present invention provides a first roller having a magnetic roll on which magnetic poles are arranged. It has a second developing body and is configured to be able to selectively drive these developing bodies to perform development, and a magnetic shielding member is interposed between the eleventh and second developing bodies so that they are close to each other. It weakens the influence of the magnetic flux density and polar distribution between the magnetic rolls in the state of

This allows individual developing operations to be performed satisfactorily.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows the structure of a two-color copying machine incorporating an imaging device according to the present invention. In Fig. 1, numeral 1 is a copying body, and the upper surface of the copying machine body is A document table 2 is provided which can freely move back and forth in the direction (direction), and an operation panel (not shown) is provided on the front edge of the top surface, on which a display, numeric keypad, color selection button, exposure setting volume, and print key are arranged. It is being

Further, a paper feed cassette 3 is attached to the right side of the apparatus main body 1, and a paper ejection tray 4 is attached to the left side. The cassette cover 5 of the paper feed cassette 3 serves as a manual feeding table 6 for manually feeding paper P' as appropriate.

A drum-shaped photoreceptor 7 is arranged approximately in the center of the copying machine main body l. A charging device 81, an optical device 9. Two-color developing device 10, which will be described later. Transfer device
l, Peeling device 12% Cleaning device 13. and an afterimage erasing device 14 are arranged in this order.

Also,? At the lower part of the J2 copying machine body, paper P which is automatically picked up from the paper feed cassette 3 via the paper feed roller 15 or paper P' which is manually fed from the manual feed table 6 is transferred to the photoreceptor 7. Il between device 1! The transfer unit 16 is guided to the transfer paper discharge tray 4 and the paper conveyance path 17
is completely formed. This paper conveyance path 170 image transfer section 1
On the upstream side of 6, there is a pair of aligning rollers 18.18.

Further, on the downstream side, a fixing device 19 and a pair of paper ejection rollers 20 are provided.
．． 20 are arranged.

Further, the optical device 9 has an exposure lamp 22 whose back portion is surrounded by a reflector 21 and a lens mirror thread 23.

The photoreceptor 7 is driven by a drive mechanism (not shown) in the direction of the arrow in synchronization with the document table 2. Masu.

The original image uniformly charged by the charging device 8 and uniformly irradiated by the exposure lamp 22 is transferred to the lens mirror system 23vc.
The image is formed on the photoreceptor 7i to form an electrostatic latent image. The static 11L latent image formed is transferred to the developing device fltl.
The developer is turned into a developer image by O and sent to the transfer device 1 side.

Automatically or manually fed paper P or P' is fed by an aligning roller pair 18.18, and the developer image previously formed on the photoreceptor 7 is transferred onto the paper P or P' by a transfer device fltzJ. do. Further, the dust toner image is peeled off from the Q photoconductor 7 by a peeling device 12 using AC corona discharge, passes through a conveyance path 17, and is melted and fixed onto the paper P (P') by a fixing device 1119, and is then transferred to a paper discharge roller. vs. 20.
20 and is discharged onto a removable tray 4.

On the other hand, residual toner remaining on the photoconductor 7 after transferring the developer image onto the paper P (P') is cleaned by the cleaning device 13, and the potential on the photoconductor 7 is lowered to a certain level by the afterimage erasing device &14. It is then placed in a state where the next copy operation is possible.

Further, a fan as a cooling device is provided in the main body of the apparatus to exhaust heat generated from the heat-generating section % non-light lamp 22 and the fixing device 19 inside the apparatus. 24 is a power switch, 25 is a door switch, and the main motor 27 is also equipped with an exhaust device 2 in order to cool down the heat generated by the 1N source 26, etc.
8 is attached for cooling.

Inside the copying machine main body l, an upper frame and a lower frame (not shown) are pivotally supported in one bubble via a support shaft (not shown), and the other ends of both frames are set at a desired angle, for example, 30 degrees.
It is configured so that it can be opened to The upper frame has a band around the photoreceptor 7, a lens mirror system 23° and an exposure lamp 22. Developing device 10. Cleaning device J3
, an afterimage erasing device 14, and the like are installed by appropriate means, a fan as a cooling device, and a paper feed roller 15 of a paper feed device. The document table 2 is also attached to the upper frame to constitute an upper unit (JA). There is also a paper feed cassette 3 in the lower frame. Transfer device k11. 2. Place the peeling 51.
Conveyance path forming guide plate 30, fixing device 19. Paper ejection roller pair 20, 20. Valley mechanism of tray 4 etc. and main motor 27
．． The power supply section 26 is assembled by appropriate means to constitute the lower unit B.

After rotating and removing the front force bar of the copying machine main body 1, the 11 sheets of paper p are opened via a housing opening/closing device (not shown).
It is configured so that it can be opened and closed along the conveyance path noah (p'). Therefore, even if the paper P (P') becomes jammed on the conveyance path 17, it can be easily removed.

Note that 18.18 corrects the inclination of the leading edge of the paper P that is automatically fed from the paper cassette 3 or the paper P' that is manually fed, and also adjusts the timing to the toner image forming operation on the photoreceptor 7. transfer paper P or P' to transfer device 1.
A pair of aligning rollers that feed toward 1Kj),
st is a manual insertion detection switch arranged at the straight bend of the aligning roller pair 18.18.

2 is a paper ejection switch, and 34 is paper P in the paper feed cassette 3.
It is a paper empty switch that detects when ... is gone.

Further, 35 is a high voltage transformer, 36 is a static elimination brush, and 38 is an auxiliary reflector.

There is also a blade solenoid that brings the cleaning blade 40 of the 39td cleaning device into contact with and away from the photoreceptor 7.

As shown in detail in FIG. 2, the developing device *lO has a developing roller 50 as a first developing member and a developing roller 5 as a second developing member.
It can selectively drive black or one other color, such as red or yellow.

Color copies of Blue and Green Toga are now available.

The developing device 10 also includes a first developing roller 50 .
a second developing unit 52 and a second developing roller 51;
The second developing unit 53 in the lower stage is fixedly provided to the copying machine main body J, and the first developing unit 52 in the upper stage can be pulled out upward in the figure. It has become. The frequently used black developer is used in the second developing unit 53 in the lower stage, and the color developer is used in the 117th) developing unit 52 in the upper stage.

Further, the first developing unit 52 includes a developing mechanism section 54 and a toy agent supply section 55, and the desktop image machine section Ia section 54 includes a developing roller 50 and a developer formed on the surface of the developing roller 50. The sliding contact portion of the magnetic brush 56 with the photoreceptor 7, that is, the developing position 57 is also provided on the upstream side.
A doctor 58 regulating the thickness of the developer 60 scrapes off the developer magnetic brush 56 on the surface of the development roller 50 provided downstream from the development position 57 and guides it to the developer storage section 59. The developer agitator 6 accommodated in the accommodating portion 59 is housed in the casing 62. Note that the developer 56a is placed through the casing 62 at a position corresponding to the upper portion of the developing roller 50. This is achieved by magnetically detecting changes in magnetic flux.

A developer concentration detector 63 is attached to detect the developer quality.

Further, the developing roller 50 passes through the center of rotation of the photoreceptor 7.
A magnetic roll 64 is provided so that the center is located above the straight line drawn at an angle α (α=510) with respect to the horizontal line L1, and a magnetic roll 64 is fitted around the magnetic roll 64 and rotates clockwise in the figure. It consists of a sleeve 65.

The & magnetic roll 64 has five magnetic pole parts 66a to 66e, and the first and second magnetic rolls 64 have five magnetic pole parts 66a to 66e. Third. Fifth magnetic pole portion 66m, 66c, 66
e is N&, second and fourth magnetic pole parts 66b and 66d are S
& becomes! D, the angle θ1 between the first magnetic pole part 66m and the second magnetic pole part 66b is θ,=50°, and the angle θ2 between the second magnetic pole part 66b and the third magnetic pole part 66c is θ ,
=71', the angle θ between the third magnetic pole part 66c and the fourth magnetic pole part 66d is θ, =60', the angle θ4 between the fourth magnetic pole part 66d and the fifth magnetic pole part 66e are set to θ and =60', respectively.

Further, the developer replenishment section 55 is provided with a developer replenishment port 67 in a hopper 68 facing the developer storage section 59 of the developing mechanism section 540, and in a state in which the developer replenishment port 67 is closed within the hopper 68. The developer replenishment roller 69 has a structure including a pair of stirring rollers 70 and 70 that stir the developer 56m in the hopper 68 so as to convey the MS agent 56m to the developer sleeve supply roller 69 side. There is.

The J second developing unit 53 has almost the same basic configuration as the first developing unit 52 described above, and has the shape of the hopper 68' of the developer replenishing section 55' and the magnetic pole of the magnetic roll 64' of the developing roller 51. The differences include the arrangement structure, the mounting position of the developer concentration detector 63', and the addition of a second scraper 8o with a narrow width (50 mm) and an inclination of approximately 20 degrees.Other components are the same. Detailed explanations will be omitted by adding dashes to the same symbols.

The magnetic roll 64' of the developing roller 51 has four magnetic pole parts 66m' to 66d', and the first and third magnetic pole parts 66
m', 66 c' is the N pole, the second and fourth magnetic pole parts 66
b' and 66d' are S poles, and the first magnetic pole part 6
The angle θ between 6a' and the second magnetic pole part 66b' is θ.

=78°, the 201a pole part 66 b'to 11g3(
The angle between the D magnetic pole part 66 c' and 't' is 0. is θ, = 70
', the 3rd degree magnetic pole part 66C' and the fat 4 magnetic pole part 66d'
The angle θ, between them is set to θ,=80°, respectively.

The magnetic roll 64' is provided with its center located on a line kLs that passes through the center of rotation of the photoreceptor 7 and is drawn at an angle β (β=10) with respect to the horizontal lIMLI.

On the other hand, each of the magnetic rolls 64 and 64' of the first developing unit 52 and the second developing unit 53 is configured to be able to rotate at a rotation angle of approximately 25 degrees. Due to the dynamic displacement operation, the developing roller 50
, 5J can be formed with developer magnetic brushes 56, 56' and removed.

Then, the magnetic rolls 64 and 64' of the first developing unit 52 and the second developing unit 53 are switched to a predetermined position by a magnetic roll driving means, which will be described later.
First developing unit 52 or second developing unit 5
A developer magnetic brush 56, 56' is formed only on the surface of one of the developing rollers 64, 64'.

That is, when operating the first developing unit 52 side, as shown in FIG. and the first magnetic pole 66a and the second magnetic pole 66b
The doctor 58 is positioned approximately midway between the magnetic roller 64' on the second developing unit 53 side and the first
The magnetic pole 66a' of the doctor 58' is arranged to face the doctor 58'.

The developer magnetic brush 56 is formed only on the surface of the developing roller 64 on the first developing unit 52 side.

In addition, when operating the second developing unit 53 side, as shown in FIG. 3, the magnetic roll 64 on the 10th IT unit 52 side is rotated approximately 25 degrees clockwise from the position shown in FIG. The first magnetic pole 66a faces the doctor 58, and the magnetic roll 64 on the second developing unit 53 side
' is rotated counterclockwise by 25 degrees and 8 degrees from the position shown in FIG.
1 so that the doctor 58' is located in the middle. The developer magnetic brush 56' is formed only on the surface of the developer 1' breaking roller 64' on the second developing unit 53 side.

E-ki roll 64. , (64') first magnetic pole 66m (6
6a') and dock 5g (5B') made of non-magnetic material.
The reason why the developer magnetic brush 56 (56') is not formed on the surface of the developing roller 50 (5J) when facing the developing roller 50 (5J) is that the magnetic flux density of the magnetic brush is in the state of a loop at the magnetic pole 66a (66a'). This is because the adsorption force for the developer 56m (56a') is weak, so it can be easily regulated by the dock 5B (5B',), and even if the sleeve 65 (65') rotates, the developer 56a (56a') will not stick to the dock. 58(
58') section.

Each drive unit of the first developing unit 52, that is, the sleeve 65 of the developing roller 50. Developer agitator 61.9Lfl
The l-agent replenishing roller 69 is connected to a l-th driving force transmission system 85, which will be described later.
The driving force is transmitted through the Also,
Driving force is transmitted to each driving part of the second developing unit 53, that is, the sleeve 65'h of the developing roller 5, and the developer agitator 61' via a second driving force transmission system 86, which will be described later. It has become so.

Above 1. The second driving force transmission system 85,86 has a configuration as shown in FIGS. Only one of the drive sections of the developing units 52 and 53 is selectively operated. In addition, it is possible to reduce the complexity of five mechanisms and the number of 811 components, and to prevent early deterioration of the developer 56a (56b') due to unnecessary stirring and conveyance.

Hereinafter, the driving force transmission system will be explained with reference to FIG. 6 (not shown in FIG. 4). No. 41 ¥1 is No. 1. 5 is a schematic front view showing the second driving force transmission system 85, 86, and FIG.
．． FIG. 7 is a sectional view showing a state in which the second driving force transmission threads 85 and 86 are opened N with the drive gear 88 as the center. The first driving force transmission system 85 has an intermediate gear 89 that meshes with the driving gear 88.
, a first driven gear 90 that meshes with this intermediate gear 89 , an intermediate gear 9 that meshes with the first driven gear 90 , and a second compliant gear 92 that meshes with this intermediate gear 91 . ing.

Further, the second drive system transmission thread 86 connects to a third driven gear 93 that meshes with the driving gear 88, an intermediate gear 94 that anastomoses with this driven gear 93, and a fourth driven gear 94 that meshes with this intermediate gear 94.
It has a driven gear 95.

When the drive gear 88 rotates normally, that is, in the direction of the solid line arrow in FIG.
When the gear groups 93, 94, and 95 of 6 rotate in the direction of the solid line arrow, and the drive gear 88 rotates in reverse, that is, in the direction of the broken line arrow B, the gear groups 89, 90 of the first driving force transmission thread 85 rotate. , 91, 92 and the second driving force transmission system 86
The gear groups 93, 94, and 95 rotate in the directions of arrows &&.

Further, the first driven gear 90 is connected to the first developing roller 50.
The second driven gear 92 is attached to the drive shaft 61a of the developer agitating body 61 via a one-way ratchet y-97, and the second driven gear 92 is attached to the drive shaft 65a integral with the sleeve 65. 61a is configured so that the driving force is transmitted only when the gears 90 and 92 rotate in the directions shown by the solid line arrows, that is, when the drive gear 88 rotates normally, and the gears 90 and 92 rotate in the direction shown by the dashed-dotted line arrows.

Further, the third driven gear 93 is connected to the drive shaft 658' that is integral with the sleeve 6φ' of the second developing roller 5, and the fourth driven gear 95 is connected to the drive shaft 618' of the developer agitator 6'. The drive shafts 65a' and 6a' are attached via a one-way clamp 97, and drive force is transmitted to each of the drive shafts 65a' and 6a' only when the gears 93 and 95 respectively rotate in the direction of the dashed arrow, that is, when the drive gear 88 is reversed. and rotates in the direction shown by the dashed-dotted line arrow.

Further, the driving gear 88 is mounted on a bearing 98 as shown in FIG.
The drive shaft 87a of the reversible motor 87 is rotatably supported via a gear mechanism 99.
It is attached to a rotating shaft 110 that interlocks with the rotary shaft 110. That is, a gear IJ1 is attached to the one-rotation shaft 110, and this gear Ill has a bearing 1 on a support shaft 114 installed between a motor mounting frame 112 and a stay 1113 integrated therewith.
Gear No. 1 rotatably attached via 1B and 115
It meshes with 6. A gear 117 with a larger diameter is integrally molded on the gear 116, and this gear 117 is attached to the gear 11' attached to the drive shaft 87a of the reversible motor 87.
It is in a state of engagement. However, the reversible motor 8
The rotation of the drive shaft 87a of No. 7 in both forward and reverse directions is performed by gears J No. 8 and 1.
17, 116, 111 to the rotating shaft 110, and the first. The second developing units 52 and 53 can be selectively operated by simply switching between forward and reverse rotation of the basiple motor 87 included in the upper stage.

The reversible motor 87 is switched between normal rotation and reverse rotation by pressing a color designation button on an operation panel (not shown). magnetic roll 6
4.64' if magnetic poles 66m, 66a' are dots 58
58'.

The intermediate gear 89 that meshes with the drive gear 88 and the first driven gear 90 is rotatably attached to the support shaft 12 via a bearing 120. The support shaft 12 is attached to the arm 23 which can swing around the entire rotation center of the housing 122 which holds the bearing 98.98 which pivotally supports the first rotation shaft 110. Its position can be changed so that it can reliably mate with the driven gear 90 of No. 1.

Furthermore, if the l-th stirring roller 20 of the l-th developing unit 52 is intermittently driven via the l-th operating mechanism 124 shown in FIG. In conjunction with this, the second stirring roller 70 and the developer replenishing roller 69 are simultaneously driven off.

That is, a ratchet gear 25 is attached to one end of the shaft 70m of the first stirring roller 70 of the first developing unit 52, and this ratchet gear 125 is interlocked with the ON/OFF operation of the solenoid 126. The lid is intermittently driven at predetermined intervals via a ratchet pawl 12B attached to an operating arm 127 that rotates.

Also, 1st. Second stirring rollers 7o, shafts 70a of 7o,
70b and the shaft 69a of the developer replenishing roller 69, sprockets (not shown) are respectively fitted, and an endless deane (not shown) is wrapped around the driving force transmission system (not shown). ), the stirring roller 70.degree. 70 and the developer replenishing roller 69 are driven together.

In addition, the stirring roller 70' of the developing unit 53 of the navy blue 2
And the dust atomizing agent sleeve supply roller 69 is operated intermittently at 1'Ti'' via a second operation Vl plate 124' having the same configuration as the preceding I-th operation mechanism 124 and a driving force transmission system having almost the same configuration. It is designed to be driven. 12. Actuation mechanism 1 of strand 1
24 and the same configuration as ml5, the same reference numerals are given a dash and detailed explanation will be omitted.

Next, the developer brush 5 is applied to the surface of the developing roller 50, 51.
7 to 9a show the structure of a magnetic roll driving means 100 ('100') for rotationally displacing the magnetic roll 64 (64') to form or remove the magnetic roll 64 (56').

This will be explained with reference to b. The above magnetic roll 64° (64'
), one end of the shaft 64a, (64a') is connected to the frame 13.
It is supported via a bearing J3 installed on the
A lever 132 is attached to its tip. 16 of this lever 132 is engaged with an engagement fllp 134B of an arm 134 rotatably mounted via a support shaft 33. Furthermore, a first support portion 134b formed at the lower part of the pivot end side of the arm 134 is connected to the solenoid 1.
A tension spring 13 is connected to the second support part 134C connected to the first langeer 1358 of 35, and formed at the upper part of one side of the pivot end.
One end of 6 is connected.

Therefore, when the solenoid 135 is in the OFF state, the arm 134 is moved by the biasing force of the tension spring 136.
The position indicated by the double dot chain in the diagram.

That is, as shown in FIG. 9(a), the first magnetic pole portion 66m
The lever 132 is held in a position where (66a') faces the dock 5B (5B'). Therefore, when the solenoid 135 is OFF, the developing roller 5
The developer brushes 56 and 56' are placed on the surface of the rollers 0 and 51 so as not to lose their shape.

Further, when the solenoid 35 is in the ON state, the arm 134 resists the urging force of the tension spring 136 as shown in FIG. lil: As shown in the position shown by the line, that is, the 91st vehicle, the first magnetic pole part 66a (66a') is moved to the dock 5s (s
The lever 132 is rotatably displaced to a position opposite to a'). Once upon a time, solenoid 35
When ON, developer brushes 56 and 56' are formed on the surfaces of the developing rollers 50 and 51.

As shown in FIGS. 2 and 3, the dock 68' includes a dock body 58a' made of a non-magnetic material, and a first dock body 58a' made of a strip-shaped iron plate provided along the longitudinal direction of the dock body 58a'. magnetic body 58b' and dock body 58
A second magnetic body 5 made of an iron plate provided at both ends of a'
8 c' and 58 c' (only one shown). The first and second magnetic bodies 58b', 58c', and 58c' are connected to the first magnetic pole portion 66.
When a' faces the dock 58' and removes the developer 66a' on the surface of the developing roll 5, the first magnetic pole portion 66a
The structure is such that lines of magnetic force are formed between the developer 56a' and the developer 56a' to more reliably prevent the developer 56a' from being taken out.

In addition, the dock 5B has a dock body 58m made of a non-magnetic material, and magnetic bodies 58C158C (only one shown) made of iron plates provided at both ends of the dock body 58a. The developer 56a is prevented from being taken out in the same manner as the dock 58' described above. The above-mentioned dock 58' is attached to the dock 58 with
A developing roll 50 facing the dock 58 is provided with a magnetic body along the longitudinal direction of the dock main body 58a as shown in FIG.
The developer 5 is drawn using the lines of magnetic force formed between the first @ pole part 66a of the developing roll 5 and the fourth magnetic pole part 66d' of the developing roll 5.
6a is prevented from being taken out.

Further, as shown in FIGS. 2 and 3, a magnetic plate 140 made of an iron plate as a magnetic shielding member is provided between the developing roll 50 and the developing roll 5 which are provided close to each other. Magnetic flux superposition of magnetic roll 64 (64')
The influence of polar distribution is weakened, and a good developer conveyance operation can be performed.

Note that 14 shown in FIGS. 2 and 3 is a developer empty detection means for detecting that i- of the developer 568' in the developer hopper 68' of the second developing unit 53 has become less than l<. A magnet 1 is attached to an actuator 143 that is integrated with a detection lever 142 that rotates according to the amount of developer.
44 is configured to operate when it comes close to a reed switch 145 as a detector provided outside the hopper 68'.

Further, as shown in FIGS. 2, 3, and 10, a cover 150 that constitutes a part of the upper surface of the apparatus main body 1 is provided on the upper surface side of the two-color developing device f10 so as to be openable and closable. When 150 is opened, a lid body 152 opens and closes the top opening 15 for replenishing the developer of the first developing unit 52, and a lid body opens and closes the top opening 151' of the second developing unit 53 for replenishing the developer. 152' is exposed. By opening these lids 152 and 152', the developer 56a, 56a' can be easily replenished from the top side.

In addition, these fish bodies 152, 152' have a color clothing section 1.
53,153' are provided.

The colors of the developers 56a' and 56a' housed inside can be easily distinguished, so that developers of different colors will not be mixed in by mistake.

On the other hand, the fc first developing unit 52 containing 56 m of color developer is of a cartridge type that can be attached to and detached from the main body 1 of the apparatus, and can be pulled up with the handle 155 (see Figure 1 O) in the upright position. It can be easily removed.

That is, the developer replenishing section 55 of the first developing unit 52
Positioning members 156 and 156 (only one shown) are attached to the rear wall of the NU, and these positioning members 15
6,156 through the support shafts 157,157 to the handle 15.
Support rod portions 155a and 155a at both ends of 5 are rotatably pivoted.

Support rod l1Il 55a, 15 of the above-mentioned handle 55
As shown in FIGS. 11 and 12, each of the hooks 158 is integrally attached to each hook 158, which is rotatable around a support shaft 157, and engages with a locking pin 159 provided on the side of the main body of the device. The configuration is such that the upward movement can be restricted. The engaging sieve 7s6a as a first positioning part formed on the lower end side of the positioning member 156 and the end surface 156b as a second positioning part formed on the positioning bin 160°16 no. provided on the Fi apparatus main body J side. The first developing unit 5 is adapted to engage and abut.
2 can be held in a predetermined position. Also, when the handle 155 is raised up, the engagement between the 7th hook 158 and the locking pin 159 is released as shown in No. 121\1 (a), and when the 1st handle 155 is brought down to the horizontal position, the 121st stem) As shown, the hook 158 is engaged with the locking pin 159, and by further pushing it from the horizontal position, the 12th
As shown in Figure (/9), the hook 158 and the locking pin 59 are securely engaged to press the developing unit 52 downward.

Therefore, if the grip 155 is placed in an upright position, the first developing unit 52 can be attached and removed, and by folding down the handle 155 after inserting the first developing unit 52, the first developing unit 52 can be fixed. Operation becomes extremely easy.

Further, the capacity of the hopper 68' of the second developing unit 53 that accommodates the frequently used black developer 56a' is set larger than the capacity of the hopper 68 of the first developing unit 52 that accommodates the color developer 56m. The developer replenishment section is dovetailed to make maintenance easier.

Next, the developing operation of the developing device 10 will be explained. First, when the two-color designation button is used to specify that the developing unit 52 side of υil be operated, the magnetic rolls 64 and 64' become in the state shown in figure M2, and the reversible motor 87 rotates forward to start the first developing unit. The sleeve 65 of the roll 50 rotates clockwise in the state shown in FIG. 2, forming a developer magnetic brush 56 on the surface of the sleeve 65.

Then, the static latent image previously formed on the photoreceptor 7 is developed with colored fAs agents 56m.

When the development of the static 11 latent image is completed in this way, the first magnetic roll 64 is rotated about 25 degrees and the f
When the M pole 66a faces the dotter 58, new formation of the developer magnetic brush 56 on the sleeve 65 is stopped, and in this state, the sleeve 65 roughly rotates a predetermined number of revolutions to remove the developer magnetic brush 56. I can come out. Furthermore, at this time.

The developer magnetic brush 56' is not applied to the second developing roller 5), either of the primary developing units 52.5.
Even if 3 is specified, the problem of color mixing does not occur.

In addition, when the black developing unit 53 is specified, the magnetic rolls 64 and 64' become the state shown in FIG.
The sleeve 65' of the developing roll 5 rotates clockwise in the state shown in FIG. 3, forming a developer magnetic brush 567 on the entrance surface of the sleeve 65'. Then, in the same manner as described in IvIJ, the scratches on the photoreceptor 7 are developed black, and then the developer magnetic brush 56' is applied from the surface of the sleeve 65'.
The developing operation ends with the removed.

On the other hand, Ruru developing unit 5 is in the developing operation state! I (53)
Developer stirring body 6 (61') and stirring &e mechanism 7o
(yo') is always operating, and the developer replenishment roller 69 (69') is the developer concentration detector 63 (63').
) The developer 56a (56a') is
A replenishment operation is performed to maintain a good developing operation.

Nao, 1st. Magnetic roll 64.6 of the second developing roller
By setting the magnetic pole arrangement structure of 4' as described above, the formation condition of the developer magnetic brushes 56 and 56' is not impaired.

In addition, since the first developing unit 52 for color development is provided above the second developing unit 53 for black development, even if the developer falls off from the upper stage for some reason, the color developer 65a is used as the second developing unit. The black color development in the developing unit 53 makes it less noticeable and does not seriously impair image quality.

〔Effect of the invention〕

As explained above, the present invention provides a first roller having a magnetic roll on which magnetic poles are arranged. A developing device having a second developing body and capable of developing by selectively driving these developing bodies, wherein a magnetic roll is interposed between the first developing body and the second developing body. Since the magnetic shielding member that weakens the influence of the magnetic flux density and polar distribution is interposed, it is possible to provide a developing device that can easily and reliably develop a plurality of colors despite having a small configuration.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic configuration diagram of a copying machine incorporating the developing device of the present invention, FIG. 2 is a schematic longitudinal sectional front view of the developing device, and FIG. 4 to 6 show the structure of the driving force transmission system, and FIG. 4 shows the meshing state of the gear group (front view, Fig. 5 is a cross-sectional view showing the developed state, Fig. 6 is a cross-sectional view showing the driving force transmission state to the drive gear, Fig. 7 is a plan view partially showing the magnetic roll drive means, and Fig. 8 is a cross-sectional view showing the state in which the driving force is transmitted to the drive gear. Similarly, FIG. 9(a) is an explanatory view showing the operating state 11, FIG. 1θ is a schematic perspective view of the developing device section, and FIG.
FIGS. 12A, 12C, and 12C are explanatory views showing the engagement and disengagement relationship between the handle and the hook. 10... Two-color developing device fit, so... First developer (developing roller), 5... Second developer (developing roller), 56, 56'... Developer magnetism brush, 5
8.58'...Dotter, 64.64'...Magnetic roll, 65.65'...Sleeve, 66a. 66a'---first magnetic pole part, 66b, 66b'
...Second 1ia & part, 66c, 66c'...Third magnetic pole part, 66d, 66d'-,, Fourth magnetic pole part,
66e... Fifth magnetic pole part, 140... Magnetic plate (magnetic shielding member). Applicant's agent Patent attorney Takehiko Suzue Figure 7 Figure 8 Figure 35 Figure 9 (a) (b)

Claims (1)

[Claims]
A developing device having a developing body and capable of selectively driving these developing bodies to perform development, wherein the magnetic flux between the magnetic rolls is maintained between the first developing body and the second developing body. A developing device characterized by interposing a magnetic shielding member that weakens the effects of density and polar distribution. (21) The developing device according to claim 1, characterized in that the magnetic shielding member is a magnetic material. (3) The developing device according to claim 2, characterized in that iron is used as the magnetic material. Developing device.