JPS60232566A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an extremely convenient and easy-to-operate image forming device by changing over a dveloping device to be used at least after end of development in the mid-way of image formation when there is a request for changing selection of the developing devices during image forming operation. CONSTITUTION:A photosensitive drum 7 is disposed in approximately the central part of a body 1. An electrifier 8 for electrification, an optical system 9, a two-color developing device 10, an electrifier 11 for transfer, an electrifier 12 for stripping, a cleaning device 13 and a destaticizing lamp 14 are successively disposed around the photosensitive drum 7. Plural pieces of the developing devices, selecting means for selecting the desired developing device among the developing devices and image forming means for forming an image in an image forming medium by using the developing device selected by the selecting means are provided. A control means for changing over the developing device to the selected developing device at least after the development in the mid-way of the image formation ends when the selection of the developing device is executed by the selecting means during the image forming operation by the image forming means is further provided.

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 Problems Therewith] In recent years, for example, copying machines have become more and more colored, and two-color color copying machines that can obtain images in colors other than black have been put into practical use.

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

Recently, color copies of various colors have been developed by providing a plurality of removable developing devices each containing a developer of a different color, and by selecting one or more developing devices from among them. A color copying machine that can perform this is being considered. In such a copying machine, it would be very convenient and easy to use if, for example, the developer could be switched (that is, the color switched) for the next copying operation while performing the normal copying operation.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an extremely convenient and easy-to-operate system that enables switching of developing devices while performing normal image forming operations. An object of the present invention is to provide an image forming apparatus.

[Summary of the Invention] In order to achieve the above object, the present invention provides a system in which, when there is a request to change the selection of a developing device during an image forming operation, the developing device to be used is switched at least after completing the developing device in the middle of image formation. This is what I did.

[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 force sensor h3 is attached to the right side of the main body 1, and a paper discharge 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 P2 as appropriate.

Further, a photosensitive drum 7 is disposed approximately in the center of the main body 1. Around the photoreceptor drum 7, there is a charging device 8, an optical system 9, and a two-color developing device (to be described later).
10, a transfer charger 11, a peeling charger 12, 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, a sheet P1 automatically taken out from the sheet feed cassette 3 via the sheet feed row 515 or a sheet P2 manually fed from the manual feed table 6 is placed between the photoreceptor drum 7 and the charged sheet for transfer. A paper conveyance path 17 is formed that leads to the paper discharge tray 4 via the image forming section 16 between the paper feeder 11 and the paper discharge tray 4 . A registration 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 into a developer image by the developing device 10 and sent to the transfer charger 11 side. On the other hand, the automatically or manually fed paper P1 or P2 is fed by a resistor 518, and a developer image previously formed on the photosensitive drum 7 is transferred by the transfer charger 11.

The paper Pi (P2) to which this developer image has been transferred is separated from the photoreceptor drum 7 by a separation 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 i-ray 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 removed by the RA imaging device 13, and the residual image on the photoreceptor drum 7 is removed by the static elimination lamp 14. The data is erased and prepared 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 The upper frame includes, around the photoreceptor drum 7, a charging device 8, an optical system 9, an exposure lamp 22, a developing device 10. Each device such as a cleaning device 13 and a static elimination lamp 14 is attached to the upper unit 1A by appropriate means.The document table 2 and paper feed roller 15 are also attached to the upper frame.
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 transport path 17 of the paper PI (P2) via a housing opening/closing device (not shown).

Further, 29 is a cleaning blade 30 of the cleaning device 13.
This is a blade solenoid for moving the photosensitive drum 7 toward and away from the photoreceptor 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 5311.3
12 selectively drives black or one other color,
For example, red, yellow, and blue.

It is now possible to perform color development on edges, etc.

That is, the developing device 10 includes a first developing device 321 including a first developing edge roller 311 and a second developing device 321 including a second developing roller 312.
The developing unit 322 is divided into two parts, and the first developing unit 322 and the first developing unit 322 are divided into two. Second
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 attached and detached so that the one being used can be pulled out upward in the figure, and the second developing device 322 in the lower stage is designed to be maintained and inspected by a service person. It is configured so that it can be attached to and detached from the main body 1 when carrying out this operation. 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 341. The developing mechanism section 33
1 is the sliding contact portion between the developing roller 5311 and the photosensitive drum 7 of the developer magnetic brush 351 formed on the surface of the developing roller 311, that is, the developing position 36! A doctor 371 is provided on the upstream side of the developer magnetic brush 351 and regulates the thickness of the developer magnetic brush 351, and a developer magnetic brush 35 is provided on the surface of the developing roller 311 and is provided on the downstream side of the developing position 361.
1 and guides it to the developer storage section 381.
91 and the developer agitating body 401 accommodated in the developer storage section 38 in the casing 41! It is configured to be housed inside. A developer concentration detector 421 is attached to the casing 411 at a position above the developing roller 311, which detects the developer concentration by magnetically detecting changes in the magnetic permeability of the developer G1. ing.

The developing roller 311 is a magnetic roll whose center is located on a straight line L2 that passes through the center of rotation of the photoreceptor drum 7 and forms an angle α (approximately 51°) with respect to the horizontal line L1. 431, and a sleeve 441 that is fitted onto the magnetic roll 431 and rotates clockwise in the figure. The magnetic roll 431 has five magnetic pole parts 451 to 491, of which magnetic pole parts 45t, 47
! , 49t are N poles, magnetic pole parts 46t, 4811. ts pole, and the angle θ1 between the magnetic pole parts 451 and 461
is about 50°, and the angle θ2 between the magnetic pole parts 4.61 and 471
is approximately 71°, the angle θ3 between the magnetic pole parts 471 and 481 is approximately 60°, and the angle θ4 between the magnetic pole parts 481 and 49 is approximately 60°.

Further, the developer replenishment section 341 includes a developer replenishment port 501.
A hopper 511 that faces the developer storage section 3811 of the developing mechanism section 335, a developer replenishment roller 5211 provided in the tray of the hopper 51 and in a state that closes the developer replenishment port 501, and the developer replenishment roller 5211. Developer G1. on the 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
The shape of the hopper 512 of No. 2, the arrangement structure of the magnetic poles of the magnetic roll 432 of the developing row 5312, the mounting position of the developer concentration detector 422, and the accompanying width (approx.
The difference is that a scraper 54 having an inclination of approximately 20° is added. Therefore, other identical components will be designated by reference numerals with the suffix character changed from "1" to "2", and detailed explanations will be omitted.・The magnetic roll 432 of the developing row 5312 has four magnetic pole parts 452.
~482, of which the magnetic pole part 452.472 is N
The magnetic pole parts 462 and 482 are S poles, and the angle θ5 between the magnetic pole parts 452 and 462 is about 78°, and the magnetic pole part 4
The angle θ6 between 62 and 472 is approximately 70°, and the magnetic pole portion 47
The angle θ7 between 2 and 482 is set to approximately 80''. Furthermore, the magnetic roll 432 passes through the rotation center of the photoreceptor drum 7 and forms an angle β (approximately 1°) with respect to the horizontal line L1.
) is provided so that the center is located on a straight line L3 drawn in a state such that

On the other hand, the magnetic rolls 43s 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 about 25 degrees, and this positive movement The developing roller 31
Developer magnetic brushes 351 and 352 can be formed on and removed from the surface of 1,312. Then, the magnetic rolls 431 and 432 of the first developing device 321 and the second developing device 322 are switched to predetermined positions by magnetic roll driving means, which will be described later.
The developer magnetic brush 35 is only on the surface of the developing row 5311, 312 of either one of the developing device 21 or the second developing device 322.
s, 352 are to be 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 development position 361, and a doctor 37 placed approximately halfway between the magnetic pole parts 451 and 461.
1 is positioned, and the magnetic roll 432 on the second developing device 322 side is set 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 531r 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 about 25 degrees clockwise from the position shown in FIG. 2 to make the magnetic pole part 451 face the doctor 371, and the magnetic zero-rule 432 on the second developing device 322 side is moved away from the position shown in FIG. Turn the magnetic pole i by approximately 25 degrees clockwise.
! The doctor 372 is positioned approximately midway between 1f 1452 and 1f 462. The developer magnetic brush 352 is formed only on the surface of the developer roller 312 on the side of the second developer 322.

In addition, the magnetic pole part 451.45 of the magnetic roll 431.432
The reason why 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 because the density of the magnetic brushes is low at the magnetic pole parts 45t and 452. This is because the force to adsorb the developers Gs and G2 is weak because they are in a canal state, so they can be easily regulated by the doctors 37s and 372, and even if the sleeves 441 and 442 rotate, the developer Gs
.

G2 never passes through the doctor parts 371 and 372.

By the way, each driving part of the first developing device 321, that is, the sleeve 441 of the developing row 5311, the developer stirring body 401,
A driving force is transmitted to the developer supply row 5521 via a first driving force transmission system 61, which will be described later. In addition, each drive section of the second developing device 322, that is, the developing row 5
A driving force is transmitted to the sleeve 442 and the developer stirring body 402 of 312 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 devices 321 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 322 is selectively operated.

Hereinafter, the driving force transmission system will be explained in detail with reference to FIGS. 4 to 6. The first driving force transmission system 61 includes an intermediate gear 65 that meshes with a driving gear 64, a first driven gear 66 that meshes with this intermediate gear 65, an intermediate gear 67 that meshes with this driven gear 66, and this intermediate gear 67. The second meshing with
It has a driven gear 68. Further, the second driving force transmission system 62 includes a third driven gear 69 that meshes with the driving gear 64.
, an intermediate gear 70 that meshes with this driven gear 69 , and a fourth auxiliary gear 71 that meshes with this intermediate gear 70 . When the drive gear 64 rotates normally, that is, in the direction of the solid line arrow in FIG. Each rotates in the direction of the solid line arrow, and the drive gear 64 rotates in reverse.

That is, when it rotates in the direction of the broken line arrow B in FIG. It has become.

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 315, and the second driven gear 68
are attached to the drive shaft 731 of the developer agitating body 401 via one-way clutches 74 and 74, respectively, and the drive shafts 72s and 731 have gears 66 and 68 that rotate in the direction of the solid line arrows, 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 gears rotate in the direction of the 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 the gear 80 is rotatably mounted on a support shaft 83 installed between a motor mounting frame 81 and a stay 82 integrated therewith via bearings 84 and 84. It meshes with the attached gear 85. A gear 86 having a larger diameter than the gear 85 is integrally formed with the gear 85, and this 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 pull motor 63 by simply switching between forward and reverse rotation.

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 43s, The magnetic pole portions 45t, 452 of 432 can be switched to face the doctors 37s, 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 row 5531 of the first developing device 321 is
The stirring roller 531 and the developer replenishing roller 52s are driven intermittently through the first actuating mechanism 921 shown in FIG. It looks like this.

That is, one stirring roller 53 of the first developing device 321
l'? A ratchet gear 941 is attached to one end of the J-axis 9 (31), and this ratchet gear 941 is connected to a swing arm 961 that rotates in conjunction with the on/off operation of a solenoid 951.
Each predetermined layer is intermittently driven via a ratchet pawl 971 attached to the plate. In addition, sprockets (not shown) are fitted to the shafts 931.98 of the stirring rows 553s and 531 and the shaft 991 of the developer replenishment roller 521, respectively, and an endless chain (not shown) is passed through them. The stirring roller 531.degree. 531 and the developer replenishing roller 521 are integrally driven via this driving force transmission system (not shown).

Further, the stirring row 5532 and the developer replenishing roller 522 of the second developing device 322 are connected to each other via a second actuating mechanism 922 having the same configuration as the first actuating mechanism* 921 described above and a driving force transmission system having approximately the same 1#l configuration. and are intermittently driven at the same time. It should be noted that the same components as the first actuation mechanism 921 are designated by symbols with the suffix of the symbol changed from "1" to "2", 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,
A shaped end is connected to the upper part 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 portion 451 (452) is moved to the position indicated by the two-dot chain line in the figure, that is, as shown in FIG.
The lever 104 is held in a position facing the lever 72). 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). In addition, when the solenoid 109 is in the ON state, the arm 106 is moved under the biasing force of the tension spring 112 to the position shown by the solid line in FIG. 8, that is, as shown in FIG. 452) to Doctor 371
The lever 104 is rotated to a position facing (372). Therefore, solenoid 10
9, 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 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. , doctor body 113
A magnetic body 1152 consisting of an iron plate provided at both ends of the magnetic body 1152.
1152 (only one is shown). The magnetic material 114, 1152, 1152 has a magnetic pole portion 452 facing the doctor 372 and the developing roller 3.
When removing the developer G2 from the surface of the developer G2, lines of magnetic force are formed between the developer G2 and the mai portion 452 to more reliably prevent the developer G2 from being taken out. Further, the doctor 371 has a doctor body 1131 made of a non-magnetic material, and magnetic bodies 115i and 115s (only one shown) made of iron plates provided at both ends of the doctor body 1131. 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 O-roller 312, as shown in FIGS. 2 and 3. The influence of distribution is weakened, and a good developer conveyance operation can be performed.

Note that 1172 shown in FIG. M2 and FIG. A permanent magnet 120 attached to an actuator 119 integrated with a detection lever 118 that rotates in response to There is. Further, although not shown, a developer remaining amount detecting device 1171 having a configuration similar to the developer remaining amount detecting device 1172 is provided for the hopper 511 of the first developing device 321 as well.

Further, as shown in FIGS. 2, 3, and 10, a hopper cover 131 that forms a part of the upper surface of the main body 1 is provided on the upper surface side of the developing device 10 and can be freely opened and closed. 131 opens and closes the top opening 1321 for replenishing the developer of the first developing device 321 and the top opening 132 of the second developing device 322 for replenishing the developer.
A lid body 1332 that opens and closes 2 is exposed.

By opening the lids 133r and 1332, the developer Gs and G2 can be easily replenished from the top side. In addition, the above-mentioned lid body 1331.13
32 is provided with color display sections 1341 and 1342, and displays the developer G1. The color of G2 can be easily distinguished, and developer of a different color is not 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 13.1 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.
512 upper surface 138t, 1382, lid body 133s
, 1332 are equipped with integrated time meters 1391 and 139, each serving as a life indicator that displays the developer life.
2, and a developer empty indicator 140s that indicates that the amount of developer in the hoppers 511 and 512 has fallen below a predetermined amount.
, 1402 are provided. Total 1S between the above cumulative IIs
9t.

1392, for example, indicates the life of the developer by measuring the rotation [1 (hour)] of the sleeves 44s and 442 that constitute the developing rollers 311 and 312, respectively. I am using an electrolytic type integrating time meter (trade name: FC timer).

On the other hand, the first developing device 32s containing the 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 34s 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 portions 144 and 144 of the handle 141 are rotatably attached to the handle 141 via support shafts 143 and 142 at 2.142. 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. Furthermore, the engagement groove 147 as a first positioning part and the end face 148 as a second positioning part formed on the lower end side of the positioning member 142 engage with the 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. Hook 1 as shown
45 is engaged with the locking pin 146, and by further pushing in from the horizontal position, the hook 145 and the locking pin 146 are engaged with the first developing device 32, as shown in FIG. 13(C).
1 is surely engaged in a state where it is pressed downward. Therefore, if the handle 141 is in an upright state, the first developing device 321 can be attached and detached, and if the handle 141 is folded down after inserting the first developing device 321, the first developing device 321 can be attached and removed.
can be fixed and its operation is extremely easy.

Next, the developing operation of the developing device 10 will be explained. First, when the M1 developer 32111tl is selected to operate using the color selection key, the magnetic rolls 43s and 432 enter the state shown in FIG. Sleeve 441 is the second
In the state shown in the figure, the sleeve 44! rotates clockwise. A developer magnetic brush 351 is formed on the surface. Then, the electrostatic latent image previously formed on the photoreceptor drum 7 is developed using a 300 ml developer. In this way, the electrostatic t! ! When the development of the image is completed, the magnetic roll 431 is rotated by about 25 degrees so that the magnetic pole part 451 faces the doctor 37s, and new formation of the developer magnetic brush 351 on the sleeve 441 is stopped. In this state, the sleeve 441 is further rotated by a predetermined amount, and the 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 as well, so that even if any of the developing devices 321 and 322 is selected next, problems such as color mixing will not occur. There is.

Further, when the second developing device 322 is in the selected state shown in FIG. 3 to develop black color, the reversible motor 63 is reversely rotated, and the sleeve 442 of the second developing roller 312 is rotated clockwise in the state shown in FIG. 3. A developer magnetic brush 352 is formed on the surface of the sleeve 4420. 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 roller 53
1 (532) is always operating, and the developer supply row 5521 (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.

FIG. 14 shows the operation panel, including a copy key 151 for executing a copy operation, an interrupt key 152 for specifying an interrupt mode for interrupt copying, and an interrupt key 152 for specifying an interrupt mode for interrupt copying. 153, a numeric keypad 154 for setting the number of copies, a number display section 155 for displaying the number of copies, a color selection key 156 for selecting the copy color (for example, black, red, blue, green), and the selected color. color indicators 157 to 160 for displaying information, and a liquid crystal display 8 for displaying operating status, etc.
11161. A density setting section 162 for setting copy density and the like are provided respectively. 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 321 is red and the second developing device 32 is red.
2 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 indicator 157 is lit. In this state, color selection key 156
When is pressed, the red copy mode is set and the first developing device 32
1 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 part of the system, and 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. A developer concentration detector 421 and a developer remaining amount detection device 1171, a developer concentration detector 422 and a developer concentration detector [1172] of the second developing device 322, the cover opening/closing detection device 1135, 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 111176 such as a battery. on the other hand,
The output of the microcomputer 171 includes an output interface circuit 1.
77 to display devices 178 such as various indicators and display sections of the operation panel, and respective pole position switching solenoids 109 and 10 of the first developing device 321 and second developing device 322.
9. The reversible amount 63. The first developing device 321
an integrating time meter 1391 of the second developing device 322, a developing bias power source 179, a charging power source 180 of the charging charger 8, and the transfer charger 11.
the transfer power source 181, the stripping type +11182 of the stripping charger 12, the static eliminating lamp 14, the developing device absent indicator 1401, 1402, the main motor 28, other various solenoids 183, and the document table 2. A document table driving device 184 to be driven, an exposure lamp control circuit 185, and the like are connected. The exposure lamp control circuit 185 controls the exposure lamp 22 according to an output signal from an automatic exposure sensor 186 that detects light from the exposure lamp 22 and a signal from the microcomputer 171.

Note that the first developing device 32s 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.
7*, 1872, and identification information generating means 1881 and 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. The signal is input to the microcomputer 171 via 172. The developing device presence/absence signal generating means 1871, 1872 and the identification information generating means 188s, 1882 each utilize a developing device connector for electrically connecting the developing device to the control circuit, as shown in FIG. It is designed to generate a signal and an identification code. 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 developer side, and the plug 193 is connected to the control circuit shown in FIG. 115 via a cable. In the jack 192, the terminal 1941 is set as a common, and a developing device presence/absence signal is generated by connecting this terminal 1941 and a terminal 1945, and also connecting the terminal 1941 and terminals 1942 to 1944 according to the developing device. By doing this, 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 195s 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 195s 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 separate developing sheet number counters for counting the number of sheets for each developing device and one total sheet number counter for counting the total number of sheets are provided, and these counters are provided for each developing device. They are selected by addressing according to their identification codes, 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 if source is turned on, the process proceeds to step A1. In step A1, the second developer 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 80, the reversible motor 63 is stopped, and the process proceeds to step A7. In step A7, the main motor 28 is turned on for a certain period of time,
Proceed to step 88. In step 88, it is checked whether or not the warming up of the heat roller 19 has been completed.
63 is turned on to enter a standby state, and in step A9, key operations on the operation panel are accepted.

Next, the process proceeds to step AIO, and it is checked whether or not the interrupt key 152 is turned on. If it is not turned on, the process proceeds to step A11, and if it is turned on, the process proceeds 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 advances 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. Then, set the set number of copies to "1", set the interrupt mode, and proceed 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 copying mode as the basic monochromatic 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 the interrupt mode is determined in step A12', the process proceeds to step A15. In step A15, the copy conditions saved in step A13 are restored, and
The selection of the developer and exposure mode is returned to the selection state immediately before starting the interrupt mode, the interrupt mode is canceled, and step A1
Proceed to step 6. In step A16, the interrupt indicator 153 on the operation panel 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. Go to step 19 above
In , if the first developing device 321 is not installed,
Step A20. Jump A21 and go to step A22
Proceed to. Further, if the color selection key 156 is not turned on in step A20, step A21. A
22 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 322 is selected in step A21, the process advances to step A24. In step A24, the first developing device 321 is selected,
Proceed to step A23. In this way, the first developing device 321
If the 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 developer contained therein is determined based on the identification code output from the selected developer, and the 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 32r, 32
It is checked which of the two 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 units 321.3
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 A2B. In step A28, it is checked whether the hopper cover 131 of the phenomenon bag @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 cassette 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, the above step A
33, if the manual paper feed mode is selected, step A3 is selected.
4 and proceed to step A35. Step A3
In step 5, it is checked whether the developer has been attached or detached based on the developer presence/absence signals from the first and second developer units 321 and 322, and if the developer has been attached or detached, the process advances to step A36. Step A
36, the signal from the cover opening/closing detection device 135 ensures that the developing unit is in i! Check whether it is @ed or not. In this case, the cover opening/closing detection device 135
1 is detected as closed, it is determined that the device 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, and the developing device returns to the 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 unit is not attached or detached in step A35, the process advances to step A3B. 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 A39
Then, 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. If no operation is performed for a certain period of time after one normal copying operation is completed in this manner, the copying mode is switched to black as a reference color and 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 copying conditions saved when setting the interrupt mode are restored, the interrupt display 153 on the operation panel is turned off, and the standby state is returned. 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 moder 63 is rotated in the direction of the selected developing device, and the process proceeds to step B3. In step B3, Kiyoshi I! ! 1 device 13's blade solenoid 29, static elimination lamp 14, main motor 28, transfer power source 181 (
The transfer charger 11), the stripping power source 182 (the stripping charger 12), and the developing bias power source 179 are 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 the process proceeds to step B8. In step B8, the charging power source 180 (
The charging device 8) is turned on to start charging the photosensitive drum 7, and at the same time, the document table 2 is moved forward to start scanning the document, and the process proceeds to step B9. In step B9, the registration roller 18 is rotated to send the paper Pl to the image transfer section 16, and the process proceeds to step BIO.

In step B10, the sheet number display section 155 on the operation panel
"1" is subtracted from the display content of the storage device 175.
1 is added to the total number of sheets counter and the number of sheets counter of the selected developing device, and the process proceeds to step B11. 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 814. In step B14, it is checked whether 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 row 518 is stopped, and the backward movement of the document table 2 is also stopped, and the process proceeds to step B16. Step 8
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 817, it is checked based on the signal from the developer concentration detector of the selected developer to see if the developer concentration in the selected developer is equal to or higher than the lower limit concentration level. If the concentration level is not higher than the lower limit concentration level, the process advances to step 819. In step 819, it is checked whether or not the developer has been continuously replenished for a certain period of time. If not, the process returns to step 817 and the above operation is repeated. If the developer has been continuously replenished 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. In step 818, the pole position switching solenoid 109 is turned off, and in step 82
Go to 0. In step 820, the reversible motor 63
is stopped and the process proceeds to step 821. In step B21, the blade solenoid 29, the main motor 28, the static elimination lamp 14, the transfer mold [181], the peeling power source 182, and the developing bias power source 179 are turned off, and the process returns to the standby state.

On the other hand, if it is determined in step 816 that the set number of copies has not been completed, the process advances to step B22. Step B
In step B22, the life of the developer is checked by checking whether the value of the sheet number counter for development separation in the storage device 175 is a predetermined value set in advance, and if the life has not expired, the process proceeds to step B23. move on. In step 823, 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".
0) Return to step B4 and repeat the above operation,
If there is a color change request (flag-1), the process advances to step 824. In step B24, the selection of the developing device is changed, and the process proceeds to step B25.

In step B25, the pole position switching solenoid of the previously selected developer is turned off, and the process proceeds to step B26. 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 82B, the developer of the same color is selected, and the process proceeds to step B25. 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 predetermined 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 A flag is 1゛°
If the value is not 1'', the process proceeds to step C4. In step c4, the timer A starts counting, and the process proceeds to step c5. In step C5, the timer A It is checked whether or not it has counted for 5 seconds, and if it has counted for 5 seconds, the process proceeds to step C6. In step c6, the A flag is set to "1", and the process proceeds to step c7. In step C5, if 5 seconds have not been counted, step C6 is jumped and the process proceeds to step c7. On the other hand, in step C3, if the flag is "1", step c8
Proceed to. In step c8, it is checked whether the developer concentration of the selected developer is lower than a predetermined value based on the signal from the developer concentration detector 421 or 422 of the selected developer. Step C
Proceed to step 9. 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 above, if the value is higher than the predetermined value, step c
9 and proceed to step C7. In this way, after the start of the copying operation, the supply of developer onto the magnetic rolls 431, 432 is started, and then the developer concentration detectors 421, 42
After a predetermined period of time (for example, about 5 seconds) when the flow of the developer to the developer flow to the developer is stabilized, the concentration is checked based on the output of the developer concentration detectors 42s and 422.Step C7
Then, it is checked whether or not the color selection key 156 on the operation panel is turned on, and if it is turned on, the process advances to step CIO. In step C10, the color change request flag is set to 1
Set +1 and proceed to step C11. In step c7, if the color selection key 156 is not turned on, 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 C12. In step CI2, the A flag is set to "0", the timer A is reset, and the power to the integrated time meter 1391 or 1392 is turned off, and the process proceeds to step C11.

In step C11, it is checked whether there is a request to display the total number of copies (entered in code using the numeric keypad 154 on the operation panel), and if there is a display request, step C
Proceed to step 13. In step C13, the contents of the total number counter in the storage device 175 are transferred to the number display section 1 on the operation panel.
55, and the process proceeds to step C14. Step C above
In step C11, if there is no request to display the total number of copies, the process advances to step C15. In step C15, the first developing device 3
21 to display the number of copies made (numeric keypad 15)
If there is a display request, the process advances to step C16.

In step C16, the first developing device 3 in the memory wave [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)
If there is a display request, the process advances to step C18. In step C)8, 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 for clearing the number of copies for each developer (on the numeric keypad 154)
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, if there is a request to change the developer selection during copying, the developer to be used will be switched at least after the image being copied has been developed, so the process will proceed normally. While performing a copying operation, for example, the developer can be switched for the next copying operation, making it very convenient and easy to use.

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, it is possible to switch the developing device while performing normal image forming operations, and it is possible to provide an image forming apparatus that is extremely convenient and has excellent operability.

[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 70-day diagram for explaining the interrupt processing operation. PI, P2...paper, 1...copying machine body, 2...document stand, 7...photosensitive drum, 10... Developing device, 321.322...
...Developer, 156...Color selection key, 15
7-160...Color display, 171...
Microcomputer, 1871, 188t, 1882...
- Identification information generation means. Applicant's agent Patent attorney Takehiko Suzue Figure 7 Figure 8 1υw9 (a) (b) Figure 10 Figure 11 (a) (b) 1j42 1j152 16 m Figure 17 Figure 17 (C) Figure 17(d)

Claims (2)

[Claims] (1) Image formation for forming an image on an image forming medium using a plurality of developing devices, a selection means for selecting a desired developing device from among these developing devices, and the developing device selected by the selection means. and an i-control means for switching to the selected developing device at least after completing the development in the middle of image formation when the selecting device selects a developing device during the image forming operation by the image forming device. An image forming device characterized by: (2) The image forming apparatus according to claim 1, wherein each of the plurality of developing units is capable of developing different colors.