JPS60229045A - Developing device - Google Patents

Abstract

PURPOSE:To perform black or color development easily and selectively and to perform the black development which is high in frequency of use while the supplement interval of a developer is made long by providing a black and a color developing means and increasing the capacity of a black developer storage part. CONSTITUTION:The developing device 10 is divided into two, i.e. the 1st and the 2nd developing units 52 and 53 as color developing means including the 1st and the 2nd developing rollers 50 and 51; and the black developer 56' a with a high frequency of use is used by the developing unit 53 provided fixedly as a lower stage and a color developer 56a is used by the developing unit 52 as an upper stage which is drawn out upward. Further, the capacity of the hopper 68' of the developing unit 53 containing the black developer 56'a is set larger than the capacity of the hopper 68 of the developing unit 52 containing the color developer 56a to prevent an immediate shortage. Consequently, black or color development is carried out selectively extremely with ease and the black development high in frequency of use is carried out while the supplement interval of the developer is made long.

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 its problems]

2. Description of the Related Art In recent years, color copying machines and the like have progressed, and two-color color copying machines and the like that can produce images in colors other than black have been put into practical use.

However, in conventional two-color color copying machines of this kind, a plurality of cartridges each having a developing device and a photoreceptor integrated therein are prepared and selectively replaced.
There was a problem that the operation was extremely troublesome.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its purpose is to achieve a state in which black or color development can be carried out extremely easily and selectively, and the replenishment interval of developer can be extended even for frequently used black development. The purpose of this invention is to provide a developing device with good maintainability, which can be handled at any time.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention has a black developing means and a color developing means, and enables selectively performing black development or color development, and also makes it possible to selectively perform black development or color development. The capacity is set to be larger than the capacity of the developer accommodating portion of the color developing means so that the developer does not run out quickly.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a two-color copying machine incorporating the developing device of the present invention. In the figure, 1 is a copying machine main body. There is a document table 2 that can freely move back and forth, and the front edge of the top surface has a display, a numeric keypad, a color selection panel, an exposure setting panel,
An operation panel (not shown) on which glint keys and the like are arranged is provided.

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 1. Around the photoreceptor 7, there is a charging device 8, an optical device 9, and a two-color developing device 10, which will be described later. Transfer device 1
A peeling device 12, a cleaning device 13, and an afterimage erasing device I4 are arranged in this order.

Further, in the lower part of the copying machine main body 1, a paper p6 automatically taken out from the paper feed cassette 3 via the paper feed roller 15 or a paper P' manually fed from the manual feed tray 6 is placed between the photoreceptor 7 and the transfer device. A paper transport path 17 is formed which leads to the paper discharge tray 4 via the image transfer section 16 between the paper sheet and the Mll.

A pair of aligning rollers 18 and 18 are arranged on the upstream side of the image transfer section 16 of the paper conveyance path 17, and a fixing device 19 and a pair of paper discharge rollers 20 and 20 are arranged on the downstream side.

Further, the optical device 9 has an exposure lamp 22 surrounded by a reflector 2 at the back and a lens mirror system 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.

First, the charging device 8 uniformly charges the exposed run plate 2.
2, the uniformly irradiated original image is transferred to the lens mirror system 2.
3 to form an image on the photoreceptor 7 to form an electrostatic latent image. The formed electrostatic latent image is turned into a developer image by the developing device 10 and is sent to the transfer device 11 side.

Automatically or manually fed paper P or P' is fed by aligning roller pair J8. Jl? The developer image previously formed on the photoreceptor i is transferred by the transfer device 11 onto the paper P or P'. Further, the developer image is peeled off from the photoreceptor 7 by a peeling device 12 using AC corona discharge, passes through a conveyance path 17, and is transferred to a fixing device 19, where the developer image is melted and fixed onto the paper p (p'), and the paper is ejected by a paper ejection roller. The paper is discharged onto a removable tray 4 at a angle of 20°20.

On the other hand, the 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 afterimage erasing device 14 lowers the potential on the photoconductor 7 below a certain level. It is ready for the next copy operation.

Further, a fan as a cooling device is provided inside the apparatus main body 1 to exhaust heat generated by the heat generating section inside the apparatus, the exposure run plate 22, and the fixing device 19. 24 is a power switch, 25 is a door switch, and an exhaust device 28 is also installed on the main motor 27 to cool down the heat generated by the power source 26, etc.
is installed for cooling.

Inside the copying machine main body 1, an upper frame and a lower frame (not shown) are pivotally supported at one end via a support shaft (not shown), and the other ends of both frames are tilted at a desired angle, for example, 30°.
It is configured so that it can be opened to The upper frame includes a charging device 8 and a lens mirror system 2 around the photoreceptor 7.
3. Exposure run f22, developing device 10. Each device such as a cleaning device 13 and an afterimage erasing device 14 is attached to the upper unit by appropriate means, and a fan as a cooling device, a paper feed roller 15 of a paper feeder, and a document table 2 are also attached to the upper frame. It constitutes IA. Further, the lower frame includes a paper feed cassette 3, a transfer device 11, a peeling device 12, a guide plate 30 for forming a transport path. Fixing device 19, paper ejection roller pair 20,
20. ) Each mechanism such as the Ray 4, the main motor 27, the power supply section 26, etc. are attached by appropriate means to constitute the lower unit IB.

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

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. an aligning roller pair which supplies paper i or P' toward the transfer device 11;
18 is a manual feed detection switch placed just before the pair of aligning rollers 18 and 18.

32 is a paper ejection switch, 34 is paper P in the paper feed cassette 3
Detects when ... is gone (-・9- Empty switch.

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

Further, 39 is a blade solenoid that brings the cleaning blade 40 of the cleaning device into and out of contact with the photoreceptor 7 .

As shown in detail in FIG. 2, the developing device 10 has a developing roller 50 as a first developing member and a developing roller 51 as a second developing member, and these developing rollers 50 and 51 are selectively driven. By doing so, it is possible to obtain a color copy of black or one other color such as red, yellow, blue, green, etc.

The developing device 10 is divided into a first developing unit 52 as a color developing means including a first developing roller 50 and a second developing unit 53 as a black developing means including a second developing roller 51. The second developing unit 53 at the lower stage is fixedly provided to the copying machine main body 1, and the first developing unit 52 at the upper stage can be pulled out upward in the figure. The frequently used black developer is used in the lower second developing unit 53, and the color developer is used in the upper first developing unit 52.

The first developing unit 52 includes a developing mechanism section 54 and a developer replenishing section 55, and the developing mechanism section 54 includes a developing roller 50 and a developer magnetic brush 56 formed on the surface of the developing row 250. A developer magnetic brush 56 is also provided on the upstream side of the sliding contact portion with the photoreceptor 7, that is, the development position 57.
a dotter 58 that regulates the thickness of the developer, and a scraper that scrapes off the developer magnetic brush 56 on the surface of the developing roller 50, which is provided downstream of the developing position 57, and guides it to the developer storage section 59.
The mother 60 and the developer stirring body 61 housed in the developer storage section 59 are housed in a casing 62 .

A developer concentration detector 63 is attached to the casing 62 at a position above the developing roller 50 to detect the developer concentration by magnetically detecting changes in the magnetic permeability of the developer 56&. There is.

Further, the developing row 250 is provided with a magnetic field so that its center is located above a straight line drawn at an angle α (α=51°) with respect to the horizontal line through the center of rotation of the photoreceptor 7. It is composed of a roll 64 and a sleeve 65 that is fitted onto the magnetic roll 64 and rotates clockwise in the figure.

Further, the magnetic roll 64 has five magnetic pole parts 66 to 66*, and the first. Third. Fifth magnetic pole part 66 m, 66 c
, 66 e is the N pole, the 21st fourth magnetic pole part 66 b, 66
d#'iS pole, first magnetic pole part 66m and second magnetic pole part 66m
The angle θ between the second magnetic pole portion 66b and the third magnetic pole portion 66e is θ=50°, and the angle θ between the second magnetic pole portion 66b and the third magnetic pole portion 66e is θ,=50°.
, 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 θ between the fourth magnetic pole part 66d and the fifth magnetic pole part 66m , are set to θ,=600, respectively.

Further, the developer replenishing section 55 has a developer replenishing port 67 facing the developer accommodating section 59 of the developing mechanism section 54, and a hot spring 68 as a developer accommodating section. A developer replenishment roller 69 is provided in the developer replenishment port 68 and closes the developer replenishment port 67, and the developer 5 in the hole 4'68 is conveyed to the developer replenishment roller 69 side.
It has a configuration including a pair of stirring rollers 70, 70 for stirring 6a.

Further, the second developing unit 53 has almost the same basic configuration as the first developing unit 52 described above, and has the shape of the hole/base 68' of the developer replenishing section 55' and the shape of the developing roller 51.
The arrangement structure of the magnetic poles of the magnetic roll 64', the mounting position of the developer concentration detector 63', and the addition of a second scrape 4'80 with a narrow width (approximately 50 cm) and an inclination of approximately 20'. The points are different. Other identical components are given the same reference numerals with dashes, and detailed explanations will be omitted.

The magnetic roll 64' of the developing row 251 has four magnetic pole parts 66'a to 66'd. Third magnetic pole part 66
'a, 66'c are N poles, 2nd. Fourth magnetic pole part 66'b
, 66'd is the S pole, and the first magnetic pole part 66'
The angle θ between a and the second magnetic pole portion 66'b. is θ, = 7
8 degrees, the second magnetic pole part 66'b and the third magnetic pole part 66'c
The angle θ between is θ6=70°, and the third magnetic pole part 66
The angle θ between 'c and the fourth magnetic pole part 66'd is θ,=
80', respectively. Further, this magnetic roll 64' is provided so that its center is located above a straight line drawn at an angle β (β-10) with respect to the horizontal line through the center of rotation of the photoreceptor 7. There is.

On the other hand, the magnetic rolls 64 and 64' of the developing unit 52 and the second developing unit 53 of WLl are each configured to be able to rotate at a rotation angle of approximately 25 degrees. Due to the dynamic displacement operation, the developing roller 5
Developer magnetic brushes 56 and 56' can be formed and removed on the surfaces of 0 and 51.

Then, the magnetic rolls 64, 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 to be described later. By this,
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. The dotter 58 is positioned approximately midway between the first magnetic pole 66a and the second magnetic pole 66b, and the magnetic roll 64/ on the second developing unit 53 side is set so that the first magnetic pole 66'a faces the dotter 58'. I'll do what I do. The developer magnetic brush 56 is formed only on the surface of the developing row 264 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 first developing unit 52 side is rotated approximately 25 degrees clockwise from the position shown in FIG. so that the first magnetic pole 66m faces the dotter 58, and the magnetic roll 64 on the second developing unit 53 side
' is rotated about 25 degrees counterclockwise from the position shown in FIG. 2 so that the dotter 58' is located approximately midway between the first magnetic pole 66'a and the second magnetic pole 66'b. and,
A developer magnetic brush 56' is formed only on the surface of the developing roller 64' on the second developing unit 53 side.

The first magnetic pole 66h (66') of the magnetic roll 64 (64')
The reason why the developer magnetic brush 56 (56') is not formed on the surface of the developing roller 50 (51) when a) is opposed to the dotter 58 (5B') made of a non-magnetic material is that the magnetic pole 6
At 6m (66'*), the magnetic flux density of the magnetic brush is in a state of flux, so the ability to attract 56m (56'h) of developer is weak, so it can be easily regulated with dotter ss (sg'). Even if the sleeve 65 (65') rotates, the developer s e;
) section.

Driving force is transmitted to each drive unit of the first developing unit 52, that is, the sleeve 65 of the developing roller 50, the developer stirring body 61, and the developer replenishing roller 69 via a first driving force transmission system 85, which will be described later. It is now possible to do so. Further, driving force is transmitted to each driving portion of the second developing unit 53, that is, the sleeve 65' of the developing row 251 and the developer stirring body 61' via a second driving force transmission system 86, which will be described later. It has become.

Above 1. The second driving force transmission system 85,86 has a configuration as shown in FIGS. 4 to 6, and is operated by forward or reverse rotation of the glue motor 8 as a common drive source. Only one of the drive units of the first and second developing units 52 and 53 is selectively operated. The mechanism is simplified, the number of parts is reduced, and early deterioration of the developer 56h (56'b) due to unnecessary stirring and transportation can be prevented.

The driving force transmission system will be described below with reference to FIGS. 4 to 6. Figure 4 is 1. Second driving force transmission system 85
．． 86, FIG. 5 is a schematic front view showing the 1.86. Second
85 is a cross-sectional view showing the driving force transmission system 85°86 of the present invention developed around the driving gear 88. FIG. The first driving force transmission system 85 includes an intermediate gear 89 that meshes with the driving gear 88, a first driven gear 90 that meshes with the intermediate gear 89, an intermediate gear 91 that meshes with the first driven gear 90, and an intermediate gear 91 that meshes with the first driven gear 90. It has a second driven gear 92 that meshes with the intermediate gear 91.

Further, the second drive system transmission system 86 includes a third driven gear 93 that meshes with the driving gear 88, an intermediate gear 94 that meshes with the driven gear 93, and a fourth driven gear 94 that meshes with the 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 A in FIG.
When each gear group 93°94.95 of the first drive power transmission system 85 rotates in the direction of the solid line arrow, and the drive gear 88 rotates in the reverse direction, that is, in the direction of the broken line arrow B, each gear group &9, 90, 91.92 and second drive-power transmission system 8
6 gear groups 93, 94, and 95 rotate in the directions indicated by the dashed arrows, respectively.

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 stirring body 6 via a one-way clutch 97, and the second driven gear 92 is attached to the drive shaft 65h integral with the sleeve 65 of 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 the third driven gear of the second developing roller 51! A fourth driven gear 95 is attached to the drive shaft 65'a of the developer agitator 61' via a one-way clutch 97, and the fourth driven gear 95 is attached to the drive shaft 65'a integral with the developer agitator 65'. 65'h.

61'a, gears 93 and 95 each rotate in the direction of the dashed line arrow, that is, only when the drive gear 88 is reversed, driving force is transmitted and the gears rotate 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 87h of the repassinol motor 81 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 111 is attached to the rotating shaft 110, and this gear 111 has a bearing 1 on a support shaft 114 installed between a motor mounting frame 112 and a stay 4113 integrated therewith.
Gear 11 rotatably attached via 15, 115
It meshes with 6. A gear 117 with a larger diameter is integrally molded on the gear 116, and this gear 117 is connected to the gear 11 attached to the drive shaft 8711 of the repulsory motor 82.
It is in mesh with 8. Therefore, the rotation of the drive shaft 87a of the repulsive motor 87 in both forward and reverse directions is controlled by the gear 118,
117. 116. 111 to the rotating shaft 110, and the first. The second developing unit) 52, 53 can be selectively operated simply by switching the reciprocal motor 87 between forward and reverse rotation.

The reversible motor 87 can be switched between forward and reverse rotation by specifying a color on the operation panel (not shown). This is done by pressing the button, and at this time, the non-operating magnetic roll 6 is moved by the magnetic roll driving means 100, 100', which will be described later.
4.64' first magnetic poles 66*, 66'* are dotter 5B
, 5g'.

Further, an intermediate gear 89 that meshes with the drive gear 88 and the first driven gear 90 is rotatably attached to a support shaft 121 via a bearing 120. The support shaft 121 is attached to an arm 123 that can swing around a rotary shaft 122 that holds the bearing 911.98 that pivotally supports the rotating shaft 110.
Its position can be changed so that it can reliably mesh with the driven gear 90 of.

Further, the first stirring roller 70 of the first developing unit 52 is intermittently driven via a first operating mechanism 124 shown in FIG.
The second agitation roller 70 and the developer replenishment roller 69 are simultaneously driven in conjunction with the movement of the developer.

That is, a ratchet gear 125 is attached to one end of the shaft 70h of the first stirring roller 70 of the first developing unit 52, and this ratchet gear 125 rotates in conjunction with the ON-OFF operation of the solenoid 126. It is intermittently driven by a predetermined amount via a ratchet pawl 128 attached to an actuating arm 127 that moves dynamically.

Also, 1st. shaft 70* of second stirring roller 70.70;
70b and the shaft 69& of the developer replenishment roller 69 are fitted with snow rockets (not shown), and an endless chain (not shown) is wrapped around them. (not shown) via an agitation roller 70.
70 and developer supply roller 69 are driven together.

Further, the stirring row 270' of the second developing unit 53
The developer replenishing roller 69 is simultaneously and intermittently driven via a second actuating mechanism 124' having the same structure as the first actuating mechanism 124 and a driving force transmission system having substantially the same structure. Note that the same components as the first actuating mechanism 124 are given the same reference numerals with a dash, and detailed description thereof will be omitted.

Next, the developer brush 5 is applied to the surfaces of the developing rollers so and si.
The configuration of the magnetic roll driving means 1oo (zoo') for rotationally displacing the magnetic roll 64 (64') in order to form or remove the magnetic roll 64 (r6') is shown in FIGS. 7 to 9 a and b. Refer to and explain. The magnetic roll 64. (6
4') axis 64m, one end of (6J'a) is frame 13
It is pivotally supported via a bearing 131 attached to 0,
A lever 132 is attached to its tip.

The tip of this lever 132 is engaged with an engagement groove 134& of an arm 134 rotatably mounted via a support shaft 133. 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 136 is connected to the second support part 134C connected to the f-jinja 135a of No. 35 and formed at the upper part of the pivot end side.
One end of is connected.

Therefore, when the solenoid 135 is in the OFF state, the arm 134 is moved to the eighth position by the biasing force of the tension spring 136.
The first magnetic pole portion 66h (66'*) is connected to the dotter 58 (5
The lever 132 is held in a position opposite to the lever 8'). Therefore, the solenoid 135 is turned OFF.
Sometimes, a developer brush 5 is provided on the surface of the developing rollers 50 and 51.
6.56' is prevented from being formed.

In addition, when the solenoid 135 is in the ON state, the arm 134 resists the biasing force of the tension spring 136 and moves to the position shown by the solid line in FIG. 8, that is, the first position as shown in FIG. Connect the magnetic pole part 661L (66'a) to the dotter 58 (5
The lever 132 is rotated to a position opposite to the lever 8'). Therefore, when the solenoid 135 is turned on, a developer brush 56.56' is formed on the surface of the developing row 250.51.

Further, as shown in FIGS. 2 and 3, the above-mentioned dotter 58' includes a dotter body 58'a made of a non-magnetic material, and a belt-shaped iron plate provided along the longitudinal direction of the dotter body 5g'a. a first magnetic body 58'b made of a dotter body 58'a, and second magnetic bodies 5B'e, 5g'c (only one of which is shown) made of iron plates provided at both ends of the dotter body 58'a. The structure is as follows.

And the above 1. Second magnetic body 5 B'b, 511
'c.

58'c is between the first magnetic pole part 66'a and the first magnetic pole part 66'a when the first magnetic pole part 66'a faces the dotter 58' and removes the developed material 56'a on the surface of the developing roll 51. The configuration is such that lines of magnetic force are formed to more reliably prevent the developer 56'a from being taken out.

Further, the dotter 58 includes a dotter body 58a made of a non-magnetic material, and a magnetic body 58c made of an iron plate provided at both ends of the dotter body 581.

58c (only one shown),
The developer 56m is prevented from being removed in the same manner as the dotter 58' described above. The dotter 58 is not provided with a magnetic material along the longitudinal direction of the dotter main body 58a like the above-mentioned dotter 58', and the first magnetic pole part 66a of the developing roll 50 facing the dotter 58 and the developing roll 51 The developer 56a is prevented from being taken out by utilizing lines of magnetic force formed between the fourth magnetic pole portion 66'd and the fourth magnetic pole portion 66'd.

Further, a second
As shown in FIG. 3, a magnetic plate 140 is provided, and the magnetic flux density of the other magnetic roll 64° (64') is
The influence of polar distribution is weakened, and a good developer conveyance operation can be performed.

Note that 141 shown in FIGS. 2 and 3 indicates the developer 5 in the developer hole/4' 5 g' of the second developing unit 53.
The developer intensity detection means detects that the amount of developer 6'a has decreased, and is a magnet attached to an actuator 143 integrated with a detection laser z-142 that rotates according to the amount of developer. 144 is configured to perform multiple operations when it comes close to a reed switch 145 as a detector provided outside the housing 968'.

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 10 so as to be openable and closable. When 150 is opened, the lid 152 opens and closes the upper opening 151 for replenishing the developer of the first developing unit 52, and the lid 152 opens and closes the upper opening 151' for replenishing the developer of the second developing unit 53. ' is exposed. By opening these lids 152 and 152', the developer 56*, 56'h can be easily replenished from the top side.

In addition, a color display section 1 is provided on these lids 152, 152'.
53 and 153' are provided, so that the colors of the developers 56'* and 56'a stored inside can be easily distinguished, and developers of different colors are not mixed in by mistake. There is.

On the other hand, the first developing unit 52 containing the color developer 56a is pulled up with the handle 155 (see FIG. 10) in an upright state by being attached to the main body 1 of the apparatus with a detachable force. In particular, it is designed to be easily removable.

That is, the developer replenishing section 55 of the first developing unit 52
Positioning members 156°156 (only one is shown) are attached to both the front and rear walls of υ, and these positioning members 156
, 156 through the support shafts 152 and 157.
0 both end support rod parts 155h, 155h are rotatably pivoted.

As shown in FIGS. 11 and 12, hooks 158 that are rotatable around a support shaft 157 are integrally attached to the support rods 155m and 155h of the handle 155, respectively, on the side of the main body 1 of the apparatus. It is configured to engage with a locking pin 159 provided in the holder to restrict upward movement.

An engagement groove 156a as a first positioning part formed on the lower end side of the positioning member 156 and an end surface 156b as a second positioning part are engaged with positioning pins 160, 161 provided on the apparatus main body 1 side. The structure is such that the first developing unit 52 can be held in a predetermined position by being brought into contact with each other. Moreover, when the handle 155 is raised, the hook 158 and the locking pin 1 are connected to each other as shown in FIG.
When the engagement with the hook 159 is released and the handle 155 is tilted to an almost horizontal position, the hook 158 is engaged with the locking pin 159 as shown in FIG. By pushing in, the hook 158 and the locking pin 159 are surely engaged to press the developing unit 52 downward, as shown in FIG. 12(c).

Therefore, if the handle 155 is in an upright state, the first developing unit 52 can be attached and detached, and if the handle 155 is folded down after inserting the first developing unit 52, the first developing unit 52 can be fixed. Operation becomes extremely easy.

Also, the capacity of the hot spring f68' of the second developing unit 53 that accommodates the frequently used black developer 56'a is greater than the capacity of the hot spring 4'68 of the first developing unit 52 that contains the color developer 56th. The size is set large to extend the developer replenishment interval and make maintenance easier.

Next, the developing operation of the developing device 10 will be explained. First, when the first developing unit 52 side is designated to be operated by color-specifying butane, the magnetic rolls 64 and 64' enter the state shown in FIG. The sleeve 65 of 50 is rotated clockwise in the state shown in FIG. 2 to form a developer magnetic brush 56 on the surface of the sleeve 65.

Then, the electrostatic latent image previously formed on the photoreceptor 7 is developed with 56 tL of color developers.

When the development of the electrostatic latent image is completed in this way, the first
The magnetic roll 64 is rotated by about 25 degrees and the first magnetic pole 66h faces the dotter 58, so that the sleeve 65
Developer magnetic to the top! New formation of Rashi 56 is stopped,
In this state, the sleeve 65 is further rotated by a predetermined amount to remove the developer magnetic brush 56. Note that at this time, the developer magnetic brush 56' is not formed on the second developing roller 5 either, so that even if any of the developing units 52 and 53 is designated next, problems such as color mixing will not occur. It looks like this.

Further, when the second developing unit 53 is designated for black development, the magnetic rolls 64, 64' are brought into the state shown in FIG.
IJ-f-65' of the developing roll 51 rotates clockwise in the state shown in FIG. A developer magnetic brush 56' is formed on the surface of 65'. Then, after developing the electrostatic latent image on the photoreceptor 7 to black in the same manner as described above,
The developing operation ends with the developer magnetic brush 56' removed from the surface of the sleeve 65'.

On the other hand, the developer agitating body 6J (61') and the agitating mechanism 70 (70) of the developing unit 52 (53) are in the developing operation state.
') is constantly operating and the developer replenishing roller 69
(69') is adapted to appropriately replenish the developer 56 m (56'x) based on a signal from the developer concentration detector 63 (63'), thereby maintaining a good developing operation.

In addition, 1. Magnetic roll 64.64 of second developing roller
' By setting the magnetic pole arrangement structure as described above,
The state of formation of the developer magnetic brushes 56, 56' is not impaired.

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

〔Effect of the invention〕

As explained above, the present invention has a black developing means and a color developing means, and is capable of selectively performing black development or color development, and also reduces the capacity of the developer storage section of the black developing means. The capacity is set to be larger than the capacity of the developer storage section of the color developing means, so that it does not run out quickly. Therefore, it is possible to provide an easy-to-maintain developing device that can perform black or color development extremely easily and selectively, and can also handle frequently used black development with long developer replenishment intervals. play.

[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 configuration of the driving force transmission system, and FIG. 41 is a front view showing the meshing state of the gear group. Fig. 5 is a sectional view showing the developed state, Fig. 6 is a sectional view showing the driving force transmission state to the driving gear, Fig. 7 is a partially sectional plan view showing the magnetic roll drive means, and Fig. 8 is the same. Front view, Figure 9 (a) (b)
10 is a schematic perspective view of the developing device section, FIG. 11 is a front view showing the fixing structure of the developing unit, and FIG. 12 (A), (B), and (C) are illustrations of the handle. FIG. 3 is an explanatory diagram showing the engagement and disengagement relationship between the hook and the hook. DESCRIPTION OF SYMBOLS 10... Two-color color developing device, 52... First developing unit (color developing means), 53... Second developing unit (black developing means), 6EI, 6B'... Developing Medicine storage section (hora 4'). Applicant's agent Patent attorney Takehiko Suzue Figure 7 Figure 8 Figure 35 Figure 9 (A) (.)

Claims (1)

[Claims] A developing device having a black developing means and a color developing means and capable of selectively performing black development or color development, wherein the capacity of the developer storage section of the black developing means is equal to the capacity of the color developing means. A developing device characterized in that the capacity of the developer storage section is set to be larger than the capacity of the developer storage section.