JPS60232568A - Image forming device - Google Patents

Abstract

PURPOSE:To enable prevention of failure in normal formation of an image in the stage of changing over developing devices by prohibiting the change in 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 on an image forming medium by using the developing device selected by the selecting means are provided. A control means for prohibiting selection of the developing device by the selecting means during the image forming operation by said 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. However, in this type of copying machine, images are not formed properly when switching the developing device, so
It is necessary to prevent selection of a developing device during normal copying operations.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and its purpose is to prevent the request from being accepted even if there is a request to change the developer selection during normal image forming operation. An object of the present invention is to provide an image forming apparatus that can prevent images from being formed normally when switching between developing devices.

[Overview of the optical system] In order to achieve the above object, the present invention is designed to prohibit changing the selection of the developing device during the image forming operation.

[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 tray 4 is attached to the left side. The cassette cover 5 of the paper feeder 1-3 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 photosensitive drum 7, there are a charging charger 8, an optical system 9, a two-color developing device 10 (to be described later), a transfer charger 11, a stripping charger 12, a cleaning device 13, and a static elimination lamp. 14 etc. are arranged in sequence. 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 roller 15 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.
An image of the document uniformly irradiated with light by the optical system 9 is formed on the photoreceptor drum 7 to form an electrostatic m-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, paper P fed automatically or manually! Alternatively, P2 is supplied by the registration roller 18, and a developer image previously formed on the photoreceptor drum 7 is transferred by the 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 1 henna 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. and prepares for the next copy 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 1A
It consists of Further, each mechanism such as a paper feed cassette 3, a transfer charger 11, a peeling charger 12, a heat roller 19, a paper discharge roller 201, a paper discharge tray 4, a main motor 28, etc. are mounted on the lower frame by appropriate means. It is attached to constitute a lower unit 1B. After the fluorocarbon cover of the main body 1 is rotated and removed, it is configured so that it can be opened and closed almost along the paper conveyance 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 bringing the photoconductor drum 7 into contact with and separating it 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 311.3
12 selectively drives black or one other color,
For example, color development such as red, yellow, blue, and green can be performed.

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 attached and detached so that the user can pull it 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. The structure is such that the main body 1 can be carefully inspected when doing so. 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 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 that regulates the thickness of the developer 351, and a developer magnetic brush 3 provided on the surface of the developing roller 311, which is provided on the downstream side of the developing device 1f 361.
A scraper 391 that scrapes off the developer 51 and guides it to the developer storage section 381 , and a developer stirring body 401 accommodated in the developer storage section 381 are housed in a casing 411 . Incidentally, a developer concentration detector 421 that detects the developer concentration by magnetically detecting changes in the magnetic permeability of the developer Gl is installed in a vertical position corresponding to the upper part of the developing row 5311 of the casing 411. It is worn.

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 451 and 47
1.491 is the N pole, magnetic pole parts 46t and 481 are the S poles, the angle θ1 between the magnetic pole parts 455 and 461 is about 50°, and the angle θ2 between the magnetic pole parts 465 and 471 is about 7
1°, and the angle θ3 between the magnetic pole parts 471 and 481 is approximately 60
°, the angle θ4 between the magnetic pole parts 481 and 491 is approximately 60°
are set respectively.

Further, the developer replenishment section 341 includes a developer replenishment port 501.
A hopper 511 facing the developer storage section 381 of the developing mechanism section 33s, and a developer replenishment roller 5 provided within the hopper 511 and closing the developer replenishment port 501.
211 and the developer G on this developer supply roller 521 side.
The configuration includes a pair of stirring rows 553s 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 accompanying scraper with a narrow width (approximately 50 m) and an inclination of approximately 206. The difference is that 54 has been 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. Note that the developing roller 3
The twelve magnetic rolls 432 have four magnetic pole parts 452 to 482.
The magnetic pole parts 452 and 472 are N poles, and 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 parts 462 and
The angle θ5 between the magnetic pole parts 472 and 48 is approximately 70°.
2 is set to approximately 80''.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. The center is located on the drawn straight line 3.

On the other hand, each of the magnetic rolls 431 and 432 of the first developing device 321 and the second developing device 322 is configured to be able to rotate at a rotation angle of about 25 degrees. The developing rollers 311, 3
Developer magnetic brushes 35s and 352 can be formed or removed on the surface of 12. The magnetic rolls 43s and 432 of the first developing device 321 and the second developing device 322 are switched to a predetermined position by a magnetic roll driving means, which will be described later.
Either the first or second developing device 322 has one developing roller 31s, and the developer magnetic brush 35 is only on the surface of the developing roller 312.
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 developing device 1361, and the 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 roller 311 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, the magnetic roll 4 of the first developing device 32 st/4
31 clockwise about 25 degrees from the position shown in FIG. 2 so that the magnetic pole part 451 faces the doctor 371, and at the same time, move the magnetic roll 432 on the second developing device 322 side counterclockwise from the position shown in FIG. The doctor 372 is rotated about 25 degrees in the direction of the shadow 1 so that the doctor 372 is located approximately midway between the magnetic pole parts 452 and 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 the developer magnetic brushes 35s and 352 are not formed on the surface of the developing roller 311 and 312 when the developer roller 35s and 352 are opposed to the doctors 371 and 372 made of non-magnetic material is that the density of the magnetic brushes is low at the magnetic pole portions 451 and 452. This is because the ability to adsorb the developers G1 and G2 is weak because they are in the state of a canal, and therefore they can be easily regulated by the doctors 371 and 372, and the sleeve 44! , 442 rotate, the developer Gl remains unchanged.

G2 never passes through the doctors 37s and 372.

By the way, each drive unit of the first developing device 32, that is, the sleeve 441 of the developing roller 311, the developer agitator 401
A driving force is transmitted to the first developer supply row 5521 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 of 1.322 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 driven gear 71 that meshes with this intermediate gear 70 . When the drive gear 64 rotates normally, that is, in the direction of the solid arrow in FIG.
9 to 71 respectively rotate in the direction of the solid line arrow, and the drive gear 64 rotates in reverse, that is, in the direction of the broken line arrow B in FIG. Each of the gears 69 to 71 of the transmission system 62 rotates 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 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 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 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 the gear 86 is attached to the oscillator motor 63.
The gear 87 is in mesh with the gear 87 attached to the drive shaft 78. 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.
21.degree. 322 can be selectively operated simply by switching the reversible motor 63 between forward and reverse rotation.

Note that the reversible motor 63 is switched between forward and reverse rotation 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, The magnetic pole portions 45t and 452 of 432 can be switched to face the doctors 371 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 row 5531 of the first developing device 321 is
It is designed to be driven intermittently via a first operating mechanism 921 shown in FIG. 4, and in conjunction with the movement of the stirring roller 5531, the other stirring roller 531 and developer replenishment row 5521 are also driven. It has become so.

That is, one stirring roller 531 of the first developing device 321
A ratchet gear 941 is attached to one end of the shaft 931, and this ratchet gear 941 is attached to a solenoid 95.
It 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 of 1. Further, sprockets (not shown) are fitted to the shafts 931.98 of the stirring row 5531, 531 and the shaft 991 of the developer replenishment roller 521, respectively, and an endless chain (not shown) is strung around them. The stirring roller 531 and the developer replenishing roller 521 are integrally driven through this driving force transmission system (not shown).

Further, the stirring row 5532 and the developer replenishment row 5522 of the second developing device 322 are simultaneously operated and operated via 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 designed to be driven. The same components as the first actuating mechanism 921 are designated by the reference numerals whose suffixes are changed from "1" to "2", and detailed explanation thereof will be omitted.゛Next, the magnetic roll driving means 1001 (1002) rotates and displaces the magnetic roll 431 (432) in order to form or remove the developer magnetic brush 351 (352) on the surface of the developing row 5311 (<312). The configuration will be explained with reference to FIGS. 7 to 9(a) and (b). The shaft 1011 (10
12) One end is attached to the bearing 1 attached to the frame 102.
03, and a lever 10 is attached to the tip of the shaft.
4 is installed. The tip of this lever 104 is connected to an arm 106 rotatably attached via a support shaft 105.
It is in a state where it is engaged with the engagement groove 107 of. moreover,
Support part 1 formed at the lower part of the pivot end side of the arm 106
08 is connected to the plunger 110 of the solenoid 109, and one end of a tension spring 112 is connected to the support part 11 formed at 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 developer roller 311 (312).

By the way, the above-mentioned doctor 372 is a doctor made of a non-magnetic material as shown in FIG. 2 and FIG. 114, and magnetic bodies 1152 and 1152 (only one of which is shown) made of iron plates provided at both ends of the doctor body 1132. And the magnetic bodies 114, 115
2.1152 is such that 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 1i pole part 452 to take out the developer G2. The structure is designed to more reliably prevent this. Further, the doctor 371 has a doctor body 1131 made of a non-magnetic material, and magnetic bodies 1151.115t (only one shown) made of iron plates provided at both ends of the doctor body 1131. The aforementioned Doctor 3
Similarly to the case of 72, the 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 has a magnetic pole part 451 of the developing roller 31s facing the doctor 371 and a magnetic pole part 482 of the developing roller 312. 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. 2 and 3. This weakens the influence and enables good developer transport operation.

Note that 1172 shown in FIGS. 2 and 3 is a developer remaining amount detection device that detects when the amount of developer G2 in the hopper 512 of the second developing device 322 has fallen 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 outer volume detection device 1171 having the same configuration as the developer remaining amount detection device 1172 is also provided for the hopper 51r of the first developing unit 32.

Further, 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 opened, a lid 1331 opens and closes a top opening 1321 for replenishing the developer of the first developing device 32N, and a top opening 1322 for replenishing the developer of the second developing device 322.
A lid body 1332 that opens and closes is exposed.

By opening the lids 1331 and 1332, the developer Gs and G2 can be easily replenished from the top side. In addition, the above-mentioned lid body 1331.133
2 has 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 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 small brim cover 131 is closed.

Further, as shown in FIGS. 10 and 11(a) and (b), the hoppers 511 of the first and second developing devices 321 and 322,
The upper surface 138t of 512, 1382, and the lid body 1331.
On both sides of 1332, cumulative time meters 139r and 139 are used as life indicators to display developer life, respectively.
2, and a developer out indicator 1401 that indicates that the amount of developer in the hoppers 511 and 512 has fallen below a predetermined amount.
．． 1402 is provided. The above cumulative time total 139s
.

1392, for example, displays the life of the developer by measuring the rotation layer (time) of the sleeves 441, 442 constituting the developing row 5311, 312, respectively. I am using an electrolytic type FI timer (trade name: FC timer).

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 shown) are attached to both the front and rear walls of the
Both end support portions 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. 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 bottle 146, and by further pushing it from the horizontal position, the hook 145 and the locking bottle 146 are connected to the first developing unit 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 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, forming a developer magnetic brush 351 on the surface of the sleeve 441'. Then, the electrostatic latent image previously formed on the photoreceptor drum 7 is developed with 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 part 451 is rotated by about 5 degrees and faces the doctor 371, new formation of the developer magnetic brush 35t on the sleeve 441 is stopped, and in this state, the sleeve 441 is further rotated by a predetermined amount. Developer magnetic brush 351
is removed. Note that at this time, the second developing roller 312
Since the developer magnetic brush 352 is not formed in either of the developing devices 321 and 322, problems such as color mixing will not occur even if any of the developing devices 321 and 322 is selected next.

Further, when the second developing device 322 is selected for black color development, the magnetic rolls 43s and 432 are brought into 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 developer stirring body 401 (402) and the stirring roller 53 of the developing device 321 (322) in the developing operation state
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.

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. content display 153, numeric keypad 154 for setting the number of copies, etc., number display section 155 for displaying the number of copies, color selection key 156 for selecting the color of copies (for example, black, red, stomach, green), selected color. Color display units 157 to 1601 for displaying information, a liquid crystal display unit 161 for displaying operating status, and a density setting unit 162 for setting copy density 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, if the first developing device 32r is red and the second developing device 322 is black, when the power is turned on, the black copy mode is automatically selected, the second developing device 322 is selected, and the color display 157 is displayed. Light. When the color selection key 156 is pressed in this state, the red copy mode is set, the first dial 321 is selected, and the color display 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 alternately selected.

FIG. 15 shows the overall control circuit.

That is, 1.71 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 remaining developer amount detection device 117s, the developer concentration detector 422 and the remaining developer 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 gf 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, an output interface circuit 17 is connected to the output of the microcomputer 171.
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 accumulating time meter 1391 of the first developing device 321, the accumulating time meter 1392 of the second developing device 322, the developing bias power source 179, the charging power source 1801 of the charging device 8, the transfer charging The transfer charger ai 181 of the device 11, the stripping charger 1I of the stripping charger 12
i182, the static elimination lamp 14, the developerless indicator 140s, 1402, the main motor 28, other various solenoids 183, the document table drive device 184 that drives the document table 2, the exposure lamp control circuit 185, etc. are connected. be done. 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 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 developing unit (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 187s, 1872 and the identification information generation means 1881 and 1882 each utilize a developer connector for electrically connecting the developer 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 developing device side, and the plug 193 is connected to the control circuit shown in FIG. 15 via a cable. In the jack 192, the terminal 1941 is set as a common terminal, and by connecting this terminal 1941 and the terminal 194s, a developing device presence/absence signal is generated.
A 3-bit identification code is generated by connecting 941 to terminals 1942 to 1944 depending on the developing device. On the other hand, in the plug 193, the terminal 195
1 is grounded on the control circuit side, and the terminal 195
2 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 19
2 and plug 193 are not connected, plug 1
Since the developing device presence signal is not obtained from the terminal 1955 of 93, it can be determined that there is no developing device and that the developing device is not installed.

Further, the storage device 175 is, for example, 0MO3RAM.
(random access memory) to make copies! It is used as a counter to count the number of copying 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 pits x 5, and is stored in a BCD code. Further, the count data of the total number counter is composed of, for example, 4 pieces x 6 pieces, 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 and idler 109 of the second developing device 322 are 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 80. In step 86, 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 A10, 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 AI2. 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 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 the interrupt mode is selected in step AI2, the process advances to step A15. In step A15, step A
The copying conditions saved in step A13 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 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
At step 20, it is checked whether or not the color selection key 156 is turned on.
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 32
Select 2 and proceed to step A23. Above step A1
9, if the first developing device 321 is not installed, 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, in step A17, the first developing device 32! is installed, or if the second
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 developer contained in the selected developer is determined based on the output identification code, 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 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 units 321, 32
The developer empty indicators 140s and 1402 of No. 2 are turned off, and the process proceeds 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 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 advances to step A27. In this way, the first and second
Developer G1. If G2 is missing, its top opening 132
1. No developer indicator 14 provided near 1322
0s, 1402 is turned on. At this time, if the hopper cover 131 is closed, the developer empty indicator 1
401.1402 does not light up, but lights up only when 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 A32
Now, the symbol 165 for displaying no developer on the operation panel.
is turned on and the process proceeds to step A31. In this way, only when the selected developing device runs out of developer, this 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 Pl 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
At step 36, 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 it 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. Step A
At step 37, the developer on the sleeve of the detached developing device is removed by performing the above-described operations, 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 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. In step A39, 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 the current mode is interrupt mode i, and if it is not the interrupt mode, the process proceeds 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, after the normal copying operation is completed,
If no operation is performed for a certain period of time R, the copying mode is switched to black as a 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 copying conditions saved when setting the interrupt mode are restored, the interrupt indicator 153 on the operation panel is turned off, and the machine returns to the 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 1ia 1180 (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 B1o.

In step B10, the sheet number display section 155 on the operation panel
At the same time as subtracting "1" from the display contents of
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 voltage 180 is turned off to stop charging the photosensitive drum 7, and the process proceeds to step 812. 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 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 B15. 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 816. Step 8
In step 16, it is checked whether or not the set number of copies have been completed. If not, the process returns to step B4 and the above-described operation is repeated; if it has been completed, step 81
Proceed to step 7. 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. Proceed to
If the concentration is not higher than the lower limit concentration level, the process advances to step 819. In step B19, it is checked whether or not the developer has been continuously replenished for a certain period vI, and if the developer has not been replenished, step B1
The process returns to step 7 and repeats the above operation, and when the developer is continuously replenished for a certain period of time, the process proceeds to step 818. In other words, in automatic developer concentration control, there is an appropriate concentration level and a lower limit concentration level for not changing the flow characteristics of the developer. to continue replenishing the developer. In step 818, 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 step 821, the blade solenoid 29, main motor 28, static elimination lamp 14, transfer power supply 181, stripping power 111182, and development bias power 1179 are turned off, and the process returns to the standby state.

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 set to 1'"
It is checked whether or not it is set to , and if it is not set to II II II, the process proceeds to step C4. In step C4, timer A starts counting, and the process proceeds to step C5.

In step C5, it is checked whether or not the timer A has counted 5 seconds, and if the timer A has counted 5 seconds, step C
Proceed to step 6. In step C6, the flag is set to 1'' and the process proceeds to step C11. In step C5, if 5 seconds have not been counted, step C6 is jumped and the process proceeds to step C11.

On the other hand, in step C3, if the flag is 1", the process proceeds to step C8. In step C8, the developer concentration detector 421 or 422 of the selected developing device
Based on the signal from , it is checked whether the developer concentration of the selected developer is lower than a predetermined value, and if it is lower, the process proceeds to step C9. In step C9,
Developer replenishment O-ra 521 or 52 of the selected developing device
2 performs a developer replenishment operation, and the process proceeds to step C11. In step C8, if the value is higher than the predetermined value, jump to step C9 and step C.
Proceed to step 11. In this way, after the start of the copying operation, the supply of the developer onto the magnetic rolls 431, 432 is started, and the flow of the developer to the developer concentration detectors 421, 422 is stabilized at the predetermined F! After fIB (for example, from about 5 seconds), the concentration is checked based on the output of the developer concentration detectors 42s and 422.

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 0'', timer A is reset, and power is turned off to the totalizing time meter 1391 or 1392, and the process proceeds to step C11. In step C11, a display request for the total number of copies (operation (entered in code using the numeric keypad 154 on the panel) is checked, and if there is a display request, step C1
Proceed to step 3. In step C13, the contents of the total number counter in the storage device 175 are transferred to the number display section 15 on the operation panel.
5, and the process proceeds to step C14. Above step C1
1, 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 32
1 to display the number of copies made (numeric keypad 154)
If there is a display request, the process advances to step C16.

In step C16, the closed 1 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)
If there is a display request, the process advances to step C18. 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 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, changing the developer selection is prohibited during copying, so even if there is a request to change the developer selection during normal copying, the request will not be accepted. First, it is possible to prevent images from being incorrectly formed when switching between developing devices.

In the above-mentioned embodiments, a case has been described in which the present invention is applied to a monochromatic color copying machine, but the present invention is not limited to this, and can be applied to a so-called multi-color copying machine that copies many colors in a layered manner, or The present invention can be applied to any image forming apparatus that forms an image using a developing device, such as a 1YUF axis.

[Effects of the Invention] As described in detail above, according to the present invention, even if there is a request to change the selection of a developer during normal image forming operation, the request is not accepted, and the image is changed when switching the developer. It is possible to provide an image forming apparatus that can prevent images from being formed incorrectly.

[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 1 for explaining the interrupt processing operation. PL, P2...paper, 1...copying machine body, 2...document stand, 7...photosensitive drum, 10... Developing device, 321.322...
...Developer, 156-...Color selection key, 157
~160...Color display, 171...Microcomputer, 1871.188t, 18B2...
Identification information generation means. Applicant's agent Patent attorney Takehiko Suzue Figure 7 Figure 8 1υ5 Figure 119 (a) (b) Figure 18 (b) Figure 19 (a)

Claims (2)

[Claims] (1) 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. An image forming apparatus comprising: an image forming means; and a control means for prohibiting the selection means from selecting a developing device during an image forming operation by the image forming means. (2) The image forming apparatus according to claim 1, wherein each of the plurality of developing units is capable of developing different colors.