JPS60239771A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus such as a color copying machine capable of making color copies of a plurality of colors.

[Technical background of the invention and its problems] In recent years, copying machines, for example, have become increasingly monotonous, and two-color copying machines that can produce images in colors other than black have been put into practical use. .

However, in conventional color copying machines of this type, a plurality of cartridges that integrate a developing device and a photoreceptor are prepared and selectively replaced, which has the problem of being extremely troublesome to operate. .

Therefore, recently, by providing a plurality of detachable developing devices each capable of developing different colors, and selecting one or more developing devices from among them,
Color copying machines capable of making color copies of various colors have been considered. In such a copying machine, the color to be copied in the previous copying operation and the color to be copied in the next copying operation are not necessarily the same color. Therefore, in order to quickly perform a copying operation of a predetermined color without causing color mixing no matter which developing device is selected during the next copying operation, it is necessary to The developer on the roller must be removed.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide color processing regardless of the previous image forming operation and regardless of which developing device is selected during the next image forming operation. It is an object of the present invention to provide an image forming apparatus that can rapidly form an image of a predetermined color without mixing.

(Summary of the Invention J In order to achieve the above object, the present invention is designed to remove the developer on the developer conveying means of the developing device used for image formation when the image formation is completed.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a two-color copying machine as an example of an image forming apparatus according to the present invention. That is, 1 is a main body of a copying machine, and a document table 2 is provided on the upper surface of the main body 1 and is movable back and forth in the left-right direction (in the direction of arrow a in the figure). Also,
A paper feed cassette 3 is attached to the right side of the main body 1, and a paper discharge 1-ray 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 P2 as appropriate.

Further, a photosensitive drum 7 is disposed approximately in the center of the main body 1. Around this photosensitive drum 7,
A charger 8 for charging, an optical system 9, a two-color developing device 10 (to be described later), a charger 11 for transfer, a charger 12 for peeling, a cleaning device 13, a static elimination lamp 14, and the like are arranged in this order. Further, in the lower part of the main body 1, paper PI automatically taken out from the paper feed cassette 3 via the paper feed roller 15 or paper P2 manually fed from the manual feed table 6 is placed between the photoreceptor drum 7 and the charged plate for transfer. Image forming section 16 between the container 11
A paper transport path 17 is formed that leads to the paper discharge tray 4 via the paper. A lens 1-roller 18 is disposed on the upstream side of the image transfer section 16 of the paper conveyance path 17, and a heat roller 19 and a paper discharge roller 20 as a fixing device are disposed on the downstream side.

Here, the optical system 9 has an exposure lamp 22 whose back portion is surrounded by a reflector 21, mirrors 23 to 26, and a lens 27.

The photosensitive drum 7 is driven by a drive mechanism (not shown) in the direction indicated by the arrow in the drawing in synchronization with the document table 2. First, the exposure lamp 2 is uniformly charged by the charging device 8.
The image of the document uniformly irradiated with light by the optical system 9 is formed on the photoreceptor drum 7 to form an electrostatic latent image. The formed electrostatic latent image is developed by the developing device 10 into a developer image, and is sent to the transfer charger 11 side. On the other hand, the automatically or manually fed paper P1 or P2 is fed by a registration roller 18, and a developer image previously formed on the photosensitive drum 7 is transferred by a transfer charger 11.

The paper Pi (P2) to which this developer image has been transferred is peeled off from the photoreceptor drum 7 by a peeling charger 12, passes through a paper conveyance path 17, and is guided to a heat roller 19, where the transferred image is melted. After being fixed, the paper is discharged to the paper discharge tray 4 by the paper discharge roller 20.

On the other hand, after the developer image is transferred onto the paper PI (P2), the residual toner remaining on the photoreceptor drum 7 is cleaned by the cleaning device 13, and the residual image on the photoreceptor drum 7 is further erased by the static elimination lamp 14. , to prepare for the next copying operation.

In the 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 rotated at a desired angle, for example, about 30 degrees. It is configured so that it can be opened to On the upper frame, various devices such as a charging device 8, an optical system 9, an exposure lamp 22, a developing device @ 10, a cleaning device @ 13, and a static elimination lamp 14 are attached around the photosensitive drum 7 by appropriate means. Furthermore, the document table 2 and paper feed roller 15 are also attached to the upper frame, and the upper unit 1△
It consists of Further, in the lower frame, various mechanisms such as a paper feed cassette 3, a transfer charger 11, a peeling charger 12, a heat roller 19, a paper ejection roller 20, a paper ejection tray 4, a main motor 28, etc. are installed as appropriate means. is attached to constitute the lower unit 1B. After the front cover of the main body 1 is rotated and removed, it is configured so that it can be opened and closed substantially along the paper conveyance path 17 of the paper PL (P2) via a housing opening/closing device (not shown).

Further, 29 is a blade solenoid for bringing the cleaning blade 30 of the cleaning i91 device 13 into contact with and separating from the photosensitive drum 7.

Next, details of the developing device 10 will be explained. Second
As detailed in the figure, the first developing roller 311 and the second developing roller 311
It has a developing roller 312, and these developing rollers 311. ．．
312 can be selectively driven to perform color development of black or one color other than black, such as red, yellow, blue, or green.

That is, the developing device 10 includes a first developing device 321 including a first developing roller 311 and a second developing device 321 including a second developing roller 312.
The developing unit 322 is divided into two parts, and these first and second developing units are divided into two parts.
The developing devices 321 and 322 are both detachable from the main body 1. In this case, the first developing device 321 in the upper stage is configured to be easily removable so that the user can pull it out upward in the figure, and the second developing device 322 in the lower stage is maintained and inspected by a service person. The structure is such that it can be overlooked with respect to the main body 1 when performing such operations. The frequently used black developer is used in the second developing device 322 in the lower stage, and the color developer is used in the first developing device 321 in the upper stage.

The first developing device 321 includes a developing mechanism section 331 and a developer replenishing section 34. The developing mechanism section 33
1 is provided at the sliding contact portion between the developing roller 311 and the photosensitive drum 7 of the developer magnetic brush 351 formed on the surface of the developing roller 311, that is, upstream of the developing position 361, and a doctor 371 regulating the thickness of the developer 351; and a developer magnetic brush 35 provided downstream from the development position 361 and on the surface of the development roller 311.
1 and guides it to the developer storage section 381.
1 and a developer agitating body 4 accommodated in the developer accommodating section 381.
01 is housed in a casing 411. A developer concentration detector 421 is attached to the casing 411 at a position above the developing roller 311, which detects the degree of developer G1 by magnetically detecting changes in the magnetic permeability of the developer G1. has been done.

Further, the developing roller 311 is provided so that its center is located on a straight line tIA [2] which passes through the center of rotation of the photoreceptor drum 7 and is drawn at an angle α (approximately 51°) with respect to the horizontal line L1. Magnetic roll 431 and this magnetic roll 43
1 and a sleeve 441 that is fitted onto the outside of the sleeve 441 and rotates clockwise in the figure. The magnetic roll 431 has five magnetic pole parts 451 to 49, of which the magnetic pole part 451.
47s, 49s are N poles, magnetic pole part 46t, 4Bs are S
The angle θ between the magnetic pole parts 451 and 461 is
1 is approximately 50°, the angle θ2 between the magnetic pole parts 461 and 471
is approximately 71°, and the angle θ4 between the magnetic pole portions 471 and 481J-IT1ume only L+ThRn' mt[ILaA+ and 491 is set to approximately 60°.

Also, the developer replenishing section 34! is the developer supply port 501
A hopper 51 facing the developer storage section 381 of the developing mechanism section 331, and a developer replenishment roller 5 provided within the hopper 511 to close the developer replenishment port 501.
21, and the developer G on the developer supply roller 521 side.
The configuration includes a pair of stirring rollers 531 and 53t that stir the developer G1 in the hopper 511 so as to convey the developer G1.

Further, the second developing device 322 is similar to the first developing device 322 described above.
It has almost the same basic configuration as 1, and the developer supply section 34
2, the shape of the hopper 512, the arrangement structure of the magnetic poles of the magnetic roll 432 of the developing roller 312, the mounting position of the developer concentration detector 422, and the narrow width of approximately 50 #II.
The difference is that a scraper 54 having an inclination of approximately 20 degrees is added (approximately I+). Therefore, other identical components will be designated by reference numerals with the suffix character changed from rsJ to "2", and detailed description thereof will be omitted. Note that the developer concentration detector 422 has its detection surface connected to the casing 41.
It is attached to the rear surface of the casing 412 in a vertical state within the interior of the casing 412. Further, the scraper 54 is a guide member for guiding the developer scraped off from the developing roller 312 to the detection surface of the developer concentration detector 422. Furthermore, the magnetic roll 432 of the developing roller 312 has four magnetic pole parts 452 to 482, of which the magnetic pole part 452
．． 472 is the north pole, and the magnetic pole parts 462 and 482 are the south pole, and the angle θ5 between the magnetic pole parts 452 and 462 is about 78.
°, the angle θ6 between the magnetic pole parts 462 and 472 is approximately 70'
, @Angle θ7 between the pole parts 472 and 482 is set to about 80°, respectively. Moreover, the magnetic roll 432 is
The center is located on a straight line 3 that passes through the center of rotation of the photosensitive drum 7 and is drawn at an angle β (approximately 1°) with respect to the horizontal line.

On the other hand, the magnetic rolls 431 and 432 of the first developing device 321 and the second developing device 322 are configured to be able to rotate at a rotation angle of approximately 25 degrees, and this rotational angle is approximately 25 degrees. Along with the displacement operation, the developing roller 311.3
Developer magnetic brushes 351 and 352 can be formed on and removed from the surface of 12. and,
The first developing device 32r
Alternatively, the developer magnetic brush 351. is applied only to the surface of the developing roller 311.312 of either one of the @2 developing devices 322.
352 is formed.

That is, when operating the first developing device 321 side,
As shown in FIG. 2, the magnetic roll 4 on the first developing device 321 side
31 with the magnetic pole part 471 facing the developing position 36e, and a doctor 37 placed approximately halfway between the magnetic pole parts 451 and 461.
! and the magnetic roll 432 on the second developing device 322 side so that the magnetic pole portion 452 faces the doctor 372. The developer magnetic brush 351 is formed only on the surface of the developing row 5311 on the first developing device 321 side.

In addition, when operating the second developing device 322 side, the third developing device 322 side is operated.
As shown in the figure, a magnetic roll 431 on the side of the first developing device 321
is rotated approximately 25 degrees clockwise from the position shown in FIG. 2 so that the magnetic pole part 451 faces the doctor 371, and the magnetic roll 432 on the second developing unit 322 is moved counterclockwise from the position shown in FIG. The doctor 372 is rotated approximately 25 degrees so that the doctor 372 is located approximately midway between the magnetic pole portions 452 and 46'2. The developer magnetic brush 352 is formed only on the surface of the developing roller 312 on the second developing device 322 side.

In addition, the magnetic pole part 451.45 of the magnetic roll 431.432
The reason why the developer magnetic brushes 351 and 352 are not formed on the surface of the developing roller 311 and 312 when the developer rollers 371 and 372 are opposed to the doctors 371 and 372 made of non-magnetic material is that the density of the magnetic brushes at the magnetic pole parts '451 and 452 is This is because the developer GIG2 can be easily regulated by the developer 371 and 372 because it is in a canal state, and even if the sleeves 44s and 442 rotate, the developer GIG2 will not pass through the doctor 371 and 372 parts.

By the way, each driving section of the first developing device 321, that is, the sleeve 441 of the developing roller 311, the developer stirring body 401,
A driving force is transmitted to the developer replenishing roller 521 via a first driving force transmission system 61, which will be described later. Further, driving force is transmitted to each drive unit of the second developing device 322, that is, the sleeve 442 of the developing roller 312, and the developer stirring body 402 via a second driving force transmission system 62, which will be described later. . The first and second driving force transmission systems 61.
Reference numeral 62 has a configuration as shown in FIGS. 4 to 6, and the first and second developing units 32 are operated by rotating a rotatable motor 63 as a common driving source in the forward or reverse direction.
Only one of the drive systems 1 and 322 is selectively operated.

The driving force transmission system will be explained below with reference to FIGS. 4 to 6. The driving force transmission system will be explained below. intermediate gear 65
It has a first driven gear 66 that meshes with the driven gear 66, an intermediate gear 67 that meshes with the driven gear 66, and a second driven gear 68 that meshes with the intermediate gear 67. Further, the second driving force transmission system 62 includes a third driven gear 6 that meshes with the driving gear 64.
9, an intermediate gear 70 that meshes with this driven gear 69, and a fourth driven gear 71 that meshes with this intermediate gear 70. Then, when the driving gear 64 rotates normally, that is, in the six directions shown by the solid line arrows in FIG. 71 rotate in the direction of the solid line arrow, and the drive gear 64 rotates in the reverse direction, that is, in the direction of the broken line arrow B in FIG.
The gears 69 to 71 of the second driving force transmission system 62 are configured to rotate in the direction of the dashed arrow.

Further, the first driven gear 66 is connected to the drive shaft 721 that is integrated with the sleeve 441 of the first developing roller 311, and the second driven gear 68
are attached to the drive shaft 731 of the developer stirring body 401 via one-way clutches 74 and 74, respectively, and the drive shafts 721 and 731 have gears 66 and 68 that rotate in the direction of the solid line arrow, that is, drive gears. The driving force is transmitted only when 64 rotates in the normal direction, and the rotation occurs in the direction of the dashed line arrow. Further, the third driven gear 69 is connected to the drive shaft 722 that is integrated with the sleeve 442 of the second developing roller 312, and the fourth driven gear 71 is connected to the drive shaft 722 of the developer agitator 402.
2 through one-way clutches 75, 75, and each drive shaft 722, 732 is connected to a gear 69.
．． 71 respectively rotate in the direction of the dashed line arrow, that is, only when the drive gear 64 is reversed, the driving force is transmitted and the drive gear 64 rotates in the direction of the dashed-dotted line arrow.

Further, the driving gear 64 has a bearing 7 as shown in FIG.
The drive shaft 78 of the reversible motor 63 is rotatably supported via the gear mechanism 77.
It is attached to a rotating shaft 79 that interlocks with the. That is,
A gear 80 is attached to the rotating shaft 79, and this gear 8o is supported by bearings '84, 84 on a support shaft 83 installed between a motor mounting frame 81 and a stay 82 integrated therewith.
It meshes with a gear 85 which is rotatably attached via the. A gear 86 having a larger diameter than the gear 85 is integrally molded with the gear 85, and the gear 86 is attached to the flexible motor 6.
The gear 87 is in mesh with the gear 87 attached to the drive shaft 78 of No. 3. Thus, the rotation of the drive shaft 78 of the reversible motor 63 in both forward and reverse directions is transmitted to the rotation shaft 79 via the gears 87, 86, 85, 80, thereby reversing the first and second developing units 321 and 322. It is possible to selectively operate the rotary motor 63 by simply switching between forward and reverse rotation of the motor 63.

Note that switching between forward and reverse rotation of the reversible motor 63 is performed by pressing a color selection key on the operation panel, which will be described later, and at this time, the non-operating magnetic roll 431. 432 II
The pole parts 45s and 452 can be switched to face the doctors 37s and 372.

Further, an intermediate gear 65 that meshes with the driving gear 64 and the first driven gear 66 is rotatably attached to a support shaft 89 via a bearing 88.

The support shaft 89 is a bearing 76°76 that pivotally supports the rotating shaft 79.
It is attached to an arm 91 that can swing around a housing 90 holding the housing 90 as a center of rotation, and its position can be changed so that it can reliably mesh with the drive gear 64 and the first driven gear 66. ing.

Further, one stirring roller 531 of the first developing device 321 is
It is designed to be driven intermittently via the first developing device 321 shown in FIG. 4, and the other stirring roller 5531 and developer supply roller 5521 are simultaneously driven in conjunction with the movement of the stirring roller 531. It looks like this. That is, a ratchet gear 941 is attached to one end of a shaft 931 of one stirring roller 531 of the first developing device 321, and the ratchet 1 to gear 941 are connected to a solenoid 95.
10 is intermittently driven by a predetermined amount via a ratchet pawl 971 attached to a swinging arm 961 that rotates and displaces in conjunction with the on and off operations. Furthermore, sprockets (not shown) are fitted to the shafts 931.98 of the stirring rollers 53*, 531 and the shaft 991 of the developer replenishing roller 525, respectively, and an endless chain (not shown) is wrapped around them. Through this driving force transmission system (not shown), the stirring roller 531°531
and developer supply roller 521 are driven together.

Further, the stirring roller 532 and the developer replenishing roller 522 of the second developing device 322 are simultaneously driven intermittently through a second operating mechanism 922 having the same configuration as the first operating mechanism 921 and a driving force transmission system having approximately the same configuration. It is now possible to do so. Note that the same components as the first actuating mechanism 921 are designated by symbols with the suffix letter changed from rtJ to f2J, and detailed description thereof will be omitted.

Next, the structure of the magnetic roll driving means 1001 (1002) for rotationally displacing the magnetic roll 431 (432) in order to form or remove the developer magnetic brush 351 (352) on the surface of the developing roller 311 (312). will be explained with reference to FIGS. 7 to 9(a) and (b). The shaft 1011 (101) of the magnetic roll 431 (432)
2) One end is a bearing 10 attached to a frame 102.
3, and a lever 104 is attached to the tip of the shaft.
is installed. The tip of this lever 104 is engaged with an engagement groove 107 of an arm 106 rotatably attached via a support shaft 105. Further, the support portion 10 formed at the lower part of the pivot end side of the arm 106
8 is connected to the plunger 110 of the solenoid 109,
One end of a tension spring 112 is connected to a support portion 111 formed at the upper portion of the pivot end side.

Therefore, when the solenoid 109 is off, the arm 106 is moved to the eighth position by the biasing force of the tension spring 112.
The magnetic pole part 451 (452) is moved to the position shown by the two-dot chain line in the figure, that is, as shown in No. 91g(a), by the doctor 371 (
372), the lever 104 is held in a position facing the lever 104. Therefore, when the solenoid 109 is off, the developer magnetic brush 351 (352) is not formed on the surface of the developing roller 311 (312). Further, when the solenoid 109 is in the ON state, the arm 106 is moved to the position shown by the solid line in FIG. 8 due to the biasing force of the tension spring 112, that is, the position shown in FIG.
As shown in , the magnetic pole part 451 (452) is
The lever 104 is rotated to a position facing (372). Therefore, solenoid 1
09, a developer magnetic brush 351 (352) is formed on the surface of the developing roller 311 (312).

By the way, as shown in FIGS. 2 and 3, the doctor 372 described above includes a doctor wooden body 1132 made of a non-magnetic material, and a magnetic body 114 made of a band-shaped iron plate provided along the longitudinal direction of this doctor body 1132. and the doctor body 113
A magnetic body 1152 made of an iron plate provided at both ends of 2,
．． 1152 (only one is shown). The magnetic bodies 114, 1152, . 115
2, when the magnetic pole part 452 faces the doctor 372 and removes the developer G2 from the surface of the developing roller 312, lines of magnetic force are formed between the magnetic pole part 452 and the developer G2 to be taken out more reliably. The structure is such that it can be prevented. Further, the doctor 371 has a doctor body 1131 made of a non-magnetic material, and magnetic bodies 1151 and 1151 (only one shown) made of iron plates provided at both ends of the doctor body 1131. In the same manner as in the case of the doctor 372 described above, removal of the developer G1 is prevented. This doctor 371 is not provided with a magnetic body along the longitudinal direction of the doctor main body 1131 like the doctor 372 described above, and the developing roller 371 facing the doctor 371 is
11 magnetic pole portion 451 and developing roller 312 magnetic pole portion 482
The developer G1 is prevented from being taken out by utilizing lines of magnetic force formed between the two.

Furthermore, a magnetic plate 116 is provided between the developing roller 311 and the developing roller 312, as shown in FIGS. The influence of distribution is weakened, and a good developer conveyance operation can be performed.

Note that 1172 shown in FIGS. 2 and 3 is a developer remaining amount detection device that detects that the amount of developer G2 in the hopper 512 of the second developing device 322 has become below a predetermined value. A configuration in which a permanent magnet 120 attached to an actuator 119 integrated with a detection lever 118 that rotates according to the amount of rotation is activated when it approaches a reed switch 121 as a detector provided outside the hopper 512. It has become. Further, although not shown, a developer remaining amount detecting device 1171 having the same configuration as the developer remaining amount detecting device 1172 is also provided for the hopper 51r of the first developing device 321.

Moreover, as shown in FIGS. 2, 3, and 10,
A hopper cover 131 that forms part of the upper surface of the main body 1 is provided on the upper surface side of the developing device 10 so as to be openable and closable. When the hopper cover 131 is opened, an upper surface opening 1321 for replenishing the developer of the first developing device 321 is opened. A lid 1331 that opens and opens and an upper opening 132 for replenishing developer of the second developing device 322
A lid body 1332 that opens and closes 2 is exposed.

By opening the lids 1331 and 1332, the developer Gz and G2 can be easily replenished from the top side. In addition, the lid body 1331, "1
332 is a color display section 134t.

1342 is provided, and the developer G housed inside.
1. The color of G2 can be easily distinguished, and developer of a different color can be prevented from being mixed in by mistake.

Further, 135 shown in FIGS. 2 and 3 is a cover opening/closing detection device for detecting opening/closing of the hopper cover 131, and a permanent magnet 13 attached to the tip of the hopper cover 131
6, and a reed switch 137 as a detector which is provided on the main body 1 side and turns on when the magnet 136 approaches when the hopper cover 131 is closed.

Further, as shown in FIGS. 10 and 11(a) and (b), the hoppers 511 of the first and second developing units 321 and 322.
At the upper surface 1381.1382 of 512, the lid body 1331,1
On both sides of 332, cumulative time meters 1391 and 1392 are used as life indicators to display developer life.
, and a developer empty indicator 1401.1 that indicates that the amount of developer in the hopper 511.512 has fallen below a predetermined amount.
402 is provided. The above cumulative time meter 1391°1
392 displays the life of the developer by measuring the amount of rotation (time) of the sleeves 44t and 442 constituting the developing rollers 311 and 312, for example. An electrolytic type integrating time meter (trade name: FC timer) is used.

On the other hand, a first developing device 321 containing color developer G1
is a cartridge type that can be freely attached to and detached from the main body 1, and can be easily removed by pulling up the handle 141 (see FIG. 10) in an upright position. That is, the developer supply section 341 of the first developing device 321
Positioning members 142 and 142 (only one is shown) are attached to both the front and rear walls of the
Both end support parts 144, 144 of the handle 141 are rotatably attached to 2.142 via support shafts 143.143. Hooks 145 that are rotatable around a support shaft 143 are integrally attached to the support portions 144 and 144 of the handle 141, respectively, as shown in FIGS. 12 and 13(a), (b), and (c). It is configured to engage with a locking pin 146 provided on the main body 1 side to restrict upward movement. In addition, a retaining groove 147 as a first positioning part and an end surface 148 as a second positioning part formed on the lower end side of the positioning member 142 engage with positioning pins 149 and 150 provided on the main body 1 side. The first developing device 321 can be held in a predetermined position by making contact with the first developing device 321. Then, when the handle 141 is raised up, the engagement between the hook 145 and the locking pin 146 is released as shown in FIG. 13(a), and when the handle 141 is brought down to a nearly horizontal position, as shown in FIG. 13(1)). The hook 145 is engaged with the locking bottle 146 as shown in FIG. 3
21 is surely engaged in a state where it is pressed downward. Therefore, if the handle 141 is in an upright state, the first developer 321 can be attached and detached, and if the handle 141 is folded down after inserting the first developer 321, the first developer 321 can be attached and removed.
1 can be fixed, and the operation is extremely easy.

Next, the developing operation of the developing device 10 will be explained. First, when the first developer 321 side is selected to operate using the color selection key, the magnetic rolls 431 and 432 enter the state shown in FIG. 2, and the reversible motor 63 rotates forward.
The sleeve 441 of the first developing roller 311 rotates clockwise in the state shown in FIG. 2, and a developer magnetic brush 351 is formed on the surface of the sleeve 441. Then, the electrostatic latent image previously formed on the photoreceptor drum 7 is visualized using the color developer G1. In this way, when the development of the electrostatic latent image is completed, the magnetic roll 431
When the magnetic pole portion 451 is rotated by a degree and faces the doctor 371, new formation of the developer magnetic brush 351 on the sleeve 441 is stopped, and in this state, the sleeve 44 plate is further rotated by a predetermined amount. Developer magnetic brush 351 is removed. Note that at this time, the developer magnetic brush 352 is not formed in the second developing row 5312 either, so that problems such as color mixing will not occur even if either of the developing devices 32s and 322 is selected next. ing.

Further, when the second developing device 322 is selected for black color development, the magnetic rolls 431 and 432 enter the state shown in FIG. rotates clockwise in the state shown in FIG. 3, forming a developer magnetic brush 352 on the surface of the sleeve 442. After the electrostatic latent image on the photosensitive drum 7 is developed to black in the same manner as described above, the developing operation is completed with the developer magnetic brush 352 removed from the surface of the sleeve 442.

Note that the developing device 32 is in the developing operation state! (322) Developer stirring body 401 (402) and stirring row 553
1 (532) is always operating, and the developer supply roller 521 (522) is the developer concentration detector 421.
The developer Gl (G2) is appropriately replenished by a control signal based on the output signal of (422), so that a good developing operation is maintained.

Figure 14 shows the operation panel.1. A copy key 151 for executing a copy operation, an interrupt key 152 for specifying an interrupt mode for interrupt copying, an interrupt indicator 153 for indicating that the interrupt mode is in effect, setting the number of copies, etc. a numeric keypad 154 to display the number of copies to be made, a number display section 155 to display the number of copies to be made, a color selection key 156 to select the copy color (for example, black, red, blue, green), color indicators 157 to 160 to display the selected color, and operations. A liquid crystal display section 161 for displaying status, etc., a density setting section 162 for setting copy density, and the like are provided. In the liquid crystal display section 161, 163 is a symbol for indicating that copying is possible, 164 is a symbol for indicating that copying is not possible, and 165 is a symbol for indicating that copying is not possible. This symbol indicates that there is no developer left in the hopper. Note that the color selection by the color selection key 156 can be alternately selected each time the color selection key 156 is pressed. That is,
For example, the first developing device 325 is red, and the second developing device 322
If the color is black, when the power is turned on, the black copying mode is automatically selected, the second developing device 322 is selected, and the color display 157 is lit. When the color selection key 156 is pressed in this state, the red copy mode is set and the first developer 321
is selected, and the color indicator 158 lights up. If the color selection key 156 is pressed again in this state, the black copy mode is set again. In this way, each time the color selection key 156 is pressed, the black copy mode and the red copy mode can be selected alternately.

FIG. 15 shows the overall control circuit.

That is, 171 is a microcomputer (hereinafter simply referred to as microcomputer) as a main control section, which controls the entire copying machine. Inputs to the microcomputer 171 include input switches 173 such as various keys on the operation panel, various other switches necessary for the copying operation, sensors 174, and the developing device 321 through the input interface circuit 172. The developer concentration detector 421 and the developer remaining amount detection device 1171, the developer concentration detector 422 and the developer remaining amount detection device 1172 of the second developing device 322, the cover opening/closing detection device 135, and the like are connected.

Further, a storage device 175 is connected to the microcomputer 171, and this storage device 175 is backed up by a backup power source 176 such as a battery. On the other hand, the output of the microcomputer 171 is connected to the output interface circuits 1 and 7.
7, a display device 178 such as various indicators and a display section of the operation panel, the first developer 321 and the second
Each pole position switching solenoid 109, 109 of the developing device 322
, the reversible motor 63, the cumulative time meter 1391 of the first developing device 321, the cumulative time meter 1392 of the second developing device 322. A developing bias power source 179, a charging power source 180 for the charging charger 8, a transfer power source 181 for the transfer charger 11, and a stripping power source 18 for the stripping charger 12.
2. The static elimination lamp 14, the developing device absent indicator 140
1.1402, the main motor 28, other various solenoids 183, a document table driving device 184 for driving the document table 2, an exposure lamp control circuit 185, and the like are connected. The exposure lamp control circuit 185 controls the exposure lamp 22
an output signal of an automatic exposure sensor 186 that detects light from;
and the exposure lamp 2 in response to signals from the microcomputer 171.
2.

Note that the first developing device 321 and the second developing device 322 each have a developing device presence/absence signal generating means 18 that indicates the presence or absence of the developing device.
71, 1872 and identification information generating means 1881, 1882 for generating an identification code unique to the developer (which also represents the color of the stored developer), and signals and identification codes from these are also input to the input interface circuit 172. is inputted to the microcomputer 171 via. The developer presence/absence signal generation means 1871 and 1872 and the identification information generation means 1
88s and 1882 are adapted to generate signals and identification codes, respectively, by utilizing a developer connector for electrically connecting the developer to a control circuit, as shown in FIG. 16, for example. That is, 191 is the above-mentioned connector, which is composed of a jack 192 and a plug 193. The jack 192 is provided on the developing device side, and the plug 193 is connected to the control circuit shown in FIG. 15 via a cable. In the jack 192, a terminal 194■ is set as a common terminal, and a developing device presence/absence signal is generated by connecting this terminal 1941 and a terminal 1945. By connecting accordingly, a 3-bit identification code is generated.On the other hand, in the plug 193, the terminal 19
51 is grounded on the control circuit side, and the terminal 19
52 to 1955 are connected to the input interface circuit 172. Therefore, when the jack 192 and the plug 193 are connected, each terminal is connected correspondingly, and as a result, the terminals 1952 to 1954 of the plug 193 provide 3-bit identification according to the connection state of the terminals in the jack 192. A code is obtained, and a developing device presence signal is obtained from the terminal 1955. Therefore, jack 1
92 and the plug 193 are not connected, since no developing device presence signal is obtained from the terminal 1955 of the plug 193, it can be determined that there is no developing device and that no developing device is installed.

Further, the storage device 175 is, for example, 0MO8RAM.
(random access memory), which is used as a counter to count the number of copies (number of copy operations).
The details will be explained below.

That is, in this embodiment, for example, a plurality of sheet number counters on the developing device side that count the number of sheets for each developing device and one total sheet number counter that counts the total number of sheets are provided, and these counters are provided for each developing device. They are selected by addressing according to the device's identification code, and count data is stored in each one. The count data of each sheet number counter is composed of, for example, 4 bits x 5, and is stored in a BCD code. Further, the count data of the total number counter is composed of, for example, 4 bits x 6, and is stored in a BCD code.

Next, the operation in the above configuration will be explained. First, the operation when the power is turned on will be explained using the flowchart shown in FIG. When the power is turned on, the process proceeds to step A1. In step A1, the second developing device 322 containing black developer as a reference color is selected, and the automatic exposure mode is selected, and the process proceeds to step A2. In step A2, the heater lamp of the heat roller 19 is turned on, and the process proceeds to step A3. In step A3, the pole position switching solenoid 109 of the second developing device 322 is turned off and the reversible motor 63 is reversed, and the process proceeds to step A4. In step A4, the reversible motor 63 is stopped, and the process proceeds to step A5.

In step A5, the pole position switching solenoid 109 of the first developing device 321 is turned off, and the reversible motor 63 is turned off.
Turn forward and proceed to step 86. In step 86, the reversible motor 63 is stopped, and the process proceeds to step A7. In this way, when the power is turned on, steps A3 to A
7, the second developing device 322 and the first developing device 321 are operated in order to remove the developer on the respective developing rollers 31t and 312. Next, in step A7, the main motor 28
Turn on and proceed to step 88. In step A8, it is checked whether or not warming up of the heat roller 19 has been completed. If it has been completed, the symbol 163 for indicating that copying is possible on the operation panel is lit to enter the standby state, and in step A9, the key on the operation panel is pressed. Accept operations. Next, the process proceeds to step A10, where it is checked whether or not the interrupt key 152 is turned on, and if it is not turned on, step A10 is performed.
The process advances to step A11, and if it is turned on, the process advances to step A12.

In step A12, it is checked whether or not the current mode is interrupt mode, and if the mode is not interrupt mode, the process proceeds to step A13. In step A13, the copy conditions immediately before the interrupt key 152 is turned on, that is, copy density, copy color, and set number of copies, are saved, and the second developer 322 containing black developer and the automatic exposure mode are saved. choose,
Furthermore, the set number of copies is set to "1", the interrupt mode is set, and the process proceeds to step A14. In this manner, when the interrupt mode is set, the immediately preceding copying conditions are saved and the copying mode is switched to black as the reference color. Next, in step A14, the interrupt indicator 153 on the operation panel is turned on, and the process proceeds to step A11. On the other hand, if it is the interrupt mode in step AI2, the process advances to step A15. In step A15, step A1
The copying conditions saved in step 3 are restored, and the selection of the developing device and exposure mode is returned to the selection state immediately before the start of the interrupt mode, the interrupt mode is canceled, and the process proceeds to step A16. In step A16, the interrupt display 1 on the operation panel
53 is turned off, and the process proceeds to step A11.

In step A11, it is checked whether the second developing device 322 is installed based on the developing device presence/absence signal from the second developing device 322, and if it is not installed, the process advances to step A17. In step A17, it is checked whether or not the first developing device 321 is installed based on the developing device presence/absence signal from the first developing device 321. If the first developing device 321 is not installed, step A17 is performed.
Proceed to step 18. In step A18, the color indicators 157 to 160 and the copy permission display symbol 163 on the operation panel are displayed.
turn off and return to standby mode.

In this way, the first developing device 321 and the second developing device 322
is not installed at all, the color indicators 157 to 160
This prohibits the display of colors by On the other hand, in step A11, if the second developing device 322 is installed, the process advances to step A19. In step A19,
It is checked whether the first developing device 321 is installed, and if it is installed, the process advances to step A20. Step A
In step A20, it is checked whether the color selection key 156 is turned on, and if it is turned on, the process advances to step A21. In step A21, it is checked whether the second developing device 322 is currently selected, and if it is not selected, the process advances to step A22. In step A22, the second developing device 322
is selected and the process proceeds to step A23. Step A19 above
If the first developing device 32 is not installed in step A20. Jump A21 and step A2
Proceed to step 2. Further, if the color selection key 156 is not turned on in step A20, step A21.
Jump to A22 and proceed to step A23. On the other hand, if the first developing device 321 is installed in step A17, or if the second developing device 321 is installed in step A21,
If the developing device 322 has been selected, the process advances to step A24. In step A24, the first developing device 321 is selected, and the process proceeds to step A23. In this way, the first developing device 32
If either the first or second developing device 322 or one of them is not installed, selection of that developing device is prohibited. In step A23, the color of the selected developer is displayed.

That is, the color of the stored developer is determined based on the identification code output from the selected developer, and a color indicator on the operation panel corresponding to the determined color is turned on. For example, if the discrimination color is black, the color display 157 is turned on, and if the discrimination color is red, the color display 158 is turned on.

After color display is performed in this way, the process advances to step A25. In step A25, the developer remaining amount detection device 1171.117
2, the first and second developing units 321 and 322
It is checked which of the developing devices is out of developer or not, and if neither is out of developer, the process advances to step A26. In step A26, the first and second developing devices 32r, 3
22 developer-free indicators 1401 and 1402 are turned off, and the process advances to step A27. On the other hand, in step A25, if one of the developing devices is out of developer, the process proceeds to step A28. In step A28, it is checked whether the hopper cover 131 of the developing device 10 is closed based on the signal from the cover opening/closing detection device 135. If it is closed, the process proceeds to step A26, and if it is not closed, the process proceeds to step A29.

In step A29, the developer empty indicator 1401 or 1402 of the corresponding developing device (developing device without developer) is turned on, and the process proceeds to step A27. In this way, the first and second
When the developer Gt, G2 runs out in the hopper 511.512 of the developing device 321.322, the upper surface opening 13
No developer indicator 1 installed near 21.1322
401.1402 is turned on. At this time, if the hopper cover 131 is closed, the developer-free indicators 1401 and 1402 are not lit, but are lit only when the hopper cover 131 is opened. In step A27, it is checked whether the developing device selected at this time is out of developer, and if not, the process proceeds to step A30. In step A30, the symbol 165 for displaying the absence of developer on the operation panel is turned off, and the process proceeds to step A31. On the other hand, in step A27, if the selected developing device is out of developer, the process proceeds to step A32. Step A3
2, the developer-free display symbol 16 on the operation panel
5 is turned on, and the process proceeds to step A31. In this way, only when the selected developing device runs out of developer,
It is displayed on the operation panel.

In step A31, it is checked whether or not there is an abnormality in the copying machine. If there is an abnormality, the abnormality is dealt with, and if there is no abnormality, the process advances to step A33.

In step A33, it is checked whether the mode is a manual paper feed mode using the manual feed table 6, and if it is not the manual paper feed mode, the process proceeds to step A34.

In step A34, it is checked whether or not there is paper P1 in the paper feed force cellars 1 to 3. If there is not, the process returns to the standby state, and if there is, the process proceeds to step A35. On the other hand, in step A33, if the manual paper feeding mode is selected, step A33 is determined.
34 and proceeds to step A35. Step A
In step A35, it is checked whether the developer has been attached or detached based on the developer presence/absence signals from the first and second developing devices 321 and 322, and if the developer has been attached or detached, the process advances to step A36. In step A36, it is checked based on the signal from the cover opening/closing detection device 135 whether or not the developing device is securely attached. In this case, the cover opening/closing detection device 135
If it detects that 1 is closed, it is determined that it is attached. When it is determined that the developing device is attached, the process advances to step A37. In step A37, the developer on the sleeve of the detached developing device is removed by performing the operations described above;
Return to standby state. In this way, when a developing device is attached or detached while the power is on, the device operates to remove the developer on the sleeve of the detached developing device after the developing device is securely attached. It is. On the other hand, if the developing device is not attached or detached in step A35, the process advances to step A38. In step A38, it is checked whether or not the copy key 151 on the operation panel is turned on. If it is turned on, the process proceeds to a copying operation to be described later. If it is not turned on, the process proceeds to step A39. Step A3
In step 9, it is checked whether or not any key operation has been performed on the operation panel for a certain period of time. If any operation has been performed, the process returns to the standby state, and if no operation has been performed, the process advances to step A40. In step A40, it is checked whether or not the current mode is interrupt mode, and if the mode is not interrupt mode, the process advances to step A41. In step A41, the second developing device 322 containing black developer and the automatic exposure mode are selected, the set number of copies is set to "1", and the process returns to the standby state. In this way, if no operation is performed for a certain period of time after the normal copying operation is completed, the mode is switched to the black copying mode as the reference color and the automatic exposure mode. On the other hand, in step A40, if it is the interrupt mode, the process advances to step A42. In step A42, the copy conditions saved when setting the interrupt mode are restored, and the interrupt indicator 153 on the operation panel is turned off.
Return to standby state. In this way, if no operation is performed for a certain period of time after interrupt copying is performed in interrupt mode, the state is returned to the state immediately before starting interrupt mode.

Next, the copying operation will be explained using the flowchart shown in FIG. When the copy key 151 on the operation panel is turned on, the process advances to step B1.

In step B1, the pole position switching solenoid 109 of the selected developing device is turned on, and the process proceeds to step B2. In step B2, the reversible motor 63 is rotated in the direction of the selected developing device, and the process proceeds to step B3. In step B3, the blade solenoid 29 of the cleaning device 13, the static elimination lamp 14, the main motor 28, the transfer power source 181 (transfer charger 11), and the stripping power source 182 (stripping charger 12)
Then, the developing bias power supply 179 is turned on, and the process proceeds to step B4. In step B4, the paper feeding operation from the paper feeding cassette 3 is started, and the process proceeds to step B5. In step B5, it is checked whether or not the document table 2 is in the normal position. If it is not in the normal position, the process proceeds to step B6 and is returned to the normal position. When the document table 2 is returned to the normal position, the process proceeds to step B7. In step B7, the exposure lamp 22 is turned on, and in step B8
Proceed to. In step B8, the charging power source 18o (charging charger 8) is turned on to start charging the photoreceptor drum 7, and at the same time, the document table 2 is advanced to start scanning the document.
Proceed to step B9. In step B9, the registration roller 18 is rotated to send the paper P1 to the image transfer section 16, and the process proceeds to step B10.

In step 810, the sheet count display section 155 on the operation panel
"1" is subtracted from the display content of the storage device 175.
The total number of sheets in the developing device and the number of sheets of the selected developing device are each incremented by 1, and the process advances to step 811. In step 811, the charging power source 180 is turned off to stop charging the photosensitive drum 7, and the process proceeds to step B12. In step B12, the exposure lamp 22 is turned off, and the process proceeds to step B13. In step B13, the document table 2 is moved backward, and the process proceeds to step B14. In step 814, it is checked whether or not the document table 2 has returned to the normal position, and if it has returned to the normal position, the process advances to step 815. In step B15, the rotation of the registration roller 18 is stopped, and the backward movement of the document table 2 is also stopped, and the process proceeds to step 816. Step B
In step 16, it is checked whether or not the set number of copies have been completed, and if the copying has been completed, the process advances to step 817. In step B17, it is checked whether the developer concentration of the selected developer is at least the lower limit concentration level based on the signal from the developer concentration detector of the selected developer, and if the developer concentration is at least the lower limit concentration level, the step is executed. The process proceeds to step 818, and if the concentration is not higher than the lower limit concentration level, the process proceeds to step B19. In step B19, it is checked whether or not the developer has been replenished continuously for a certain period of time. If not, the process returns to step B17 and the above operation is repeated. If the developer has been replenished continuously for a certain period of time, step 8
Proceed to step 18. In other words, in automatic developer concentration control,
It has an appropriate concentration level and a lower limit concentration level for not changing the flow characteristics of the developer, and drives the developing device until the developer concentration reaches the lower limit concentration level at the end of the copying operation,
It continues to replenish the developer. Next, step 81
At B, the pole position switching solenoid 109 is turned off and the process proceeds to step B20. In step 820, the reversible motor 63 is stopped, and the process proceeds to step B21. in this way,
When the copying operation is completed, the polar position switching solenoid 109 is turned off and the dust bashable motor 63 is stopped, thereby removing the developer on the developing roller of the selected (that is, the currently used) developing device. be. Next, in step B21, the blade solenoid 29, the main motor 28, the static elimination lamp 14, the transfer power source 181, the stripping power source 182, and the developing bias power source 179 are turned off, and the system returns to the standby state.

On the other hand, if the set number of copies have not been completed in step 816, the process advances to step B22. Step B
In step 22, the life of the developer is checked by checking whether the value of the sheet number counter on the developing device side in the storage device 175 is a predetermined value set in advance, and if the life has not expired, step 823 Proceed to. In step B23, it is checked whether there is a color change request by checking whether a color change request flag, which will be described later, is set to 1'', and if there is no color change request (flag=0).
Returning to step B4, the above-described operations are repeated, and if there is a color change request (flag-1), the process proceeds to step 824.

In step 824, the selection of the developing device is changed, and the process proceeds to step 825.

In step 825, the pole position switching solenoid of the previously selected developer is turned off, and the process proceeds to step 826. In step 826, the reversible motor 63 is stopped, and the process returns to step B1 to repeat the above-described operation. In this manner, when there is a request to change the selection of a developer during a copying operation, the developer to be used is switched at least after the development of the image being copied is completed. On the other hand, the step 82
In Step 2, if the life of the developer has expired, proceed to step B2.
Proceed to step 7. In step B27, it is checked whether there is another developer of the same color. If not, the process returns to step B4 and the above-described operation is repeated. If there is another developer of the same color, the process advances to step 828. In step B28, the developer of the same color is selected, and the process proceeds to step 825. In this way, when the developer in the developing device you are using reaches the end of its life,
If there is another developing device, that is, a developing device containing developer of the same color, switching to that developing device is performed preferentially.

Next, interrupt processing will be explained using the flowchart shown in FIG. This interrupt processing is set to be repeated at regular intervals. Once the interrupt processing is started, the process advances to step C1.

In step C1, it is checked whether the reversible motor 63 is rotating (the developing device is in operation), and if it is rotating, the process advances to step C2. In step C2, the integrated time meter 1391 or 1392 of the selected developing device is energized, and the process proceeds to step C3. In step C3, the flag is “1”
It is checked whether it is 111 II or not, and if it is not 111 II, the process proceeds to step C4. In step C4,
Timer A starts counting, and the process advances to step C5. In step C5, it is checked whether or not the timer A has counted for 5 seconds, and if it has counted for 5 seconds, then step C6
Proceed to. In step C6, the flag is set to 1'', and the process proceeds to step C7. In step C5 above,
If 5 Sec has not been counted, jump to step C6 and proceed to step C7. On the other hand, if the A flag is set to '1' in step C3, the process proceeds to step C8. In step C8, the selected developer is Check whether the developer concentration in the container is lower than a predetermined value set in advance, and if it is lower, proceed to step C9.
Proceed to. In step C9, a developer replenishment operation is performed by driving the developer replenishment roller 521 or 522 of the selected developing device, and the process proceeds to step C7. In step C8, if the value is higher than the predetermined value, step C9
Jump to step C7. In this way, after the start of the copying operation, the developer concentration detector 421, 422 starts supplying the developer onto the magnetic roll 431, 432.
After a predetermined period of time (for example, about 5
From sec onwards, the concentration is checked based on the outputs of the developer concentration detectors 42r and 422. In step C7, it is checked whether the color selection key 156 on the operation panel is turned on, and if it is turned on, the process proceeds to step 010. In step C10, the color change request flag is set to 1", and the process proceeds to step 011. If the color selection key 156 is not turned on in step C7, step C10 is jumped and the process proceeds to step C11.

On the other hand, in step C1, the reversible motor 6
If 3 is not rotating, the process advances to step CI2. In step CI2, the flag is set to "OI+", timer A is reset, and the power to the integrated timer 1391 or 1392 is turned off, and the process proceeds to step C11. In step C11, a display request for the total number of copies is made ( If there is a display request, the process proceeds to step C13.In step C13, the storage device 175
The content of the total number of sheets counter is displayed on the number of sheets display section 155 on the operation panel, and the process proceeds to step C14. In step C11, if there is no request to display the total number of copies, the process advances to step C15. In step C15, it is checked whether there is a request to display the number of copies made by the first developing device 321 (inputted in code using the numeric keypad 154), and if there is a request to display, the process proceeds to step C16.

In step C16, the first developing device 3 in the storage device 175
The contents of the sheet number counter corresponding to No. 21 are displayed in the sheet number display section 155.
is displayed, and the process proceeds to step C14.

In step C15, if there is no display request, the process advances to step C17. In step C17, the second developing device 3
22 to display the number of copies made (numeric keypad 15)
4), and if there is a display request, the process advances to step 018. In step 018, the contents of the sheet number counter corresponding to the second developing device 322 in the storage device 175 are displayed on the sheet number display section 155, and the process proceeds to step C14. In step C17, if there is no display request, the process advances to step C19.

In step C19, the normal number of copies is displayed on the number display section 155, and the process proceeds to step C14. In step C14, a request to clear the number of copies for each development type (on the numeric keypad 154) is made.
If there is no clear request, the interrupt process ends here, and if there is a clear request, the process proceeds to step C20. In step C20, the contents of the sheet number counter corresponding to the designated developer in the storage device 175 are cleared, and the interrupt processing is ended.

With the configuration described above, when a copying operation is completed, the developing device used for that copying operation is operated to remove the developer on the developing roller (sleeve) of the developing device, so that the copying operation is completed. Sometimes, the developer on the developing roller of each developing device is removed. therefore,
Regardless of the previous copying operation, no matter which developing device is selected in the next copying operation, there is no color mixing, and the copying operation of a predetermined color can be quickly performed.

In the above embodiment, a case was explained in which the present invention is applied to a monochromatic color copying machine, but the present invention is not limited to this. The present invention can be applied to any image forming apparatus that forms an image using a developing device.

[Effects of the Invention] As described in detail above, according to the present invention, regardless of the previous image forming operation, no matter which developing device is selected during the next image forming operation, there is no color mixing and a predetermined color is produced. It is possible to provide an image forming apparatus that can quickly form an image.

[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 color copying machine, Fig. 2 is a schematic vertical side view of a developing device, and Fig. 3 shows different operating states of the developing device. 4 to 6 show the configuration of the driving force transmission system, FIG. 4 is a front view showing the meshing state of the gear group, and FIG. 5 is a cross-sectional view showing the developed state. 6 is a sectional view showing the state of driving force transmission to the drive gear, FIG. 7 is a partially sectional plan view of the magnetic roll driving means, and FIG. 8 is a side view of the magnetic roll driving means. 9 is an explanatory diagram showing the operating state of the magnetic roll drive means, FIG. 10 is a schematic perspective view of the developing device section, FIG. 11 is a plan view showing the top surface of each developing device, and FIG.
Figure 2 is a front view showing the fixing structure of the developing device, Figure 13 is an explanatory diagram showing the relationship between the handle and the hook, Figure 14 is a plan view of the operation panel, and Figure 15 is the overall control circuit. A schematic block diagram, FIG. 16 is an explanatory diagram for explaining the developing unit presence/absence signal generation means and identification information generation means, and FIG.
18 is a flowchart for explaining the operation when the power is turned on, FIG. 18 is a flowchart for explaining the copying operation, and FIG. 19 is a flowchart for explaining the interrupt processing operation. PI, P2... Paper, 1... Copying machine body, 2...
・Document table, 7... Photosensitive drum, 1o... Developing device, 311° 312... Developing roller (developer conveying means)
, 321°322...Developer, 441.442...
Sleeve, 156... Color selection key, 157-160 Color indicator, 171... Microcomputer, 1881.1882
...Identification information generation means. Applicant's agent Patent attorney Takehiko Suzue Figure 7 Figure 8 1υ Soa 9 (a') (b) 1o! I'1 Figure 11 (a) (b) Figure 16 Figure 17 Figure 18 Figure 19 (a)

Claims (2)

[Claims] (1) A plurality of developing devices each containing a developer of a different color and each equipped with a developer conveying means for conveying the developer, and a selection means for selecting a desired developing device from among these developing devices. , an image forming means for forming an image of a desired color on an image forming medium using the developing device selected by the selecting means, and a developing device used for forming the image when the image forming means finishes forming the image. An image forming apparatus comprising: a control means for operating a developing device to remove the developer on the agent conveying means. (2) The image forming apparatus according to claim 1, wherein the developer transport means is a developing row that transports the developer while rotating.