JP2811091B2 - Developing drive of color image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a color image forming apparatus for forming a color image by a plurality of developing devices provided on a peripheral portion of an image carrier by an electrophotographic method. The present invention relates to a development driving device that performs driving and toner supply.

[Background of the Invention]

Many methods and apparatuses have been proposed for obtaining a color image using electrophotography. For example, as disclosed in JP-A-61-100770, a latent image is formed and developed according to the number of color separations of a document image on a photosensitive drum as an image carrier,
There is a method in which a multicolor image is formed on a transfer drum by transferring the image on a transfer drum each time development is performed and then transferred onto a recording paper to obtain a color copy. In the apparatus according to this method, it is necessary to provide a transfer drum having a size capable of transferring one image on the peripheral surface in addition to the photosensitive drum, and the apparatus has a large and complicated structure. Inevitable.

Further, as disclosed in, for example, JP-A-61-149972, a latent image is formed and developed on a photosensitive drum in accordance with the number of separated colors of an original image, and is transferred onto a transfer material each time development is performed. This is a method of obtaining a multi-color copy. In this method, it is difficult to accurately superimpose multi-color images, and a high-quality color copy cannot be obtained.

In addition, there is a method in which a latent image is formed on the photosensitive drum in accordance with the number of separated colors of the original image and development with color toner is repeated, and a color image is obtained by superimposing and transferring a color toner image on the photosensitive drum. The basic process of this multicolor image formation is described in Japanese Patent Application Laid-Open Nos. 60-75850 and 60-76766 by the present applicant,
Nos. 60-95456, 60-95458, 60-158475 and the like.

In a multi-color image forming apparatus that obtains a color image by such superposition, a plurality of developing devices that store color toners of different colors are arranged on the periphery of the photosensitive drum. Rotates the photoconductor drum several times,
The color image is obtained by developing the latent image on the photosensitive drum.

[Object of the invention]

A plurality of developing devices provided on the peripheral edge of the photosensitive drum and containing developers of different colors are operated alternately at the time of image formation to develop a latent image portion to form a toner image. During development, a developing bias voltage is applied to the developing sleeve while rotating the developing sleeve and other agitation rollers, etc. Control of ON / OFF operation of the motor rotation has been performed. Alternatively, power is transmitted to a plurality of developing units using a single motor as a power source, and a connection / disconnection switching means using an electromagnetic clutch is provided between power transmission systems, or a solenoid and a spring clutch are used. It has been possible to control the required rotational drive of the developing device by providing a switching means for switching on and off, and operating the switching means.

In addition, since toner is consumed by development during image formation, if continuous development is performed without replenishing the toner, when a two-component developer is used, the toner ratio in the developer decreases, and high-quality Images cannot be obtained. To this end, a toner box containing toner is connected to each of the developing devices. For example, when the toner ratio of the developer in the developing device decreases, toner is supplied from the toner replenishing box to the developing device. That has been done.

For switching and driving of toner supply from the conventional toner supply box, a small motor is provided in each toner supply box portion, and when it is detected that the toner concentration has decreased, the small motor is driven for a certain time to supply toner. Has been made.

A motor is provided for switching the driving of the developing device and the driving of the toner replenishment, and the rotation and stop are controlled, or an expensive electromagnetic clutch is used to electrically control the driving, thereby increasing the cost. Was something.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing driving device for a color image forming apparatus in which the switching between the driving of a developing device and the driving of toner supply can be correctly performed at low cost.

[Configuration of the invention]

The above object is provided with a plurality of developing devices, and a plurality of toner replenishing units for replenishing toner corresponding to each of the developing devices,
A developing drive device for a color image forming apparatus that forms a color image by switching between driving of the plurality of developing devices and driving of the plurality of toner replenishing units, provided in correspondence with each of the plurality of developing devices. A plurality of spring clutches for development, a plurality of spring clutches for toner supply provided corresponding to each of the plurality of toner supply units, and a plurality of spring clutches for development facing each of the plurality of development spring clutches. A plurality of developing cams each having an uneven portion having a different phase, and a plurality of toner replenishing portions each having an uneven portion each having a different phase, provided opposite to each of the plurality of toner supply spring clutches. A plurality of cams, a single developing drive motor for driving the plurality of developing units and the plurality of toner replenishing units, and driving the plurality of developing cams and the plurality of toner replenishing cams And a single cam drive source for,
The developing spring clutch and the toner replenishing spring clutch have a claw portion that can be engaged with the developing cam or the convex portion of the toner replenishing cam. The developing cam and the plurality of toner replenishing cams are rotated to change the positions of the concave and convex portions opposed to the developing spring clutch or the toner replenishing spring clutch. The development driving device of the color image forming apparatus is characterized in that the connection of the development driving motor to the container and the plurality of toner supply units is switched.

[Description of Configuration of the Invention]

As described above, the present invention constitutes a power transmission system branched from one motor to each developing unit and each toner supply unit, and a spring clutch is provided in the middle of the branched power transmission system. On the other hand, a cam which is rotated by one cam drive source is provided, and the cam is opposed to the spring clutch between each of the developing unit and the toner replenishing unit. The rotation is transmitted by the positional relationship of the opposed cam. Or do not transmit (slip).

FIG. 8 shows the positional relationship between the cross section of the spring clutch and the cam. The spring clutch S has a shaft S01 (S02) that is divided into front and rear parts in the figure, one of which is a driving side and the other is a driven side. S03 is a wound spring that is wound tightly over the shaft S01 and the shaft S02, and has a sleeve S04 surrounding the wound spring S03. One end S03a of the coil spring S03 rises and is engaged with the groove S04a provided in the sleeve S04. A claw S05 is provided on the sleeve S04 so as to protrude.

The cam C located opposite to the spring clutch S is a face cam and has a convex portion C01 and a concave portion C02. When the concave portion C02 is opposed to the cam C with respect to the spring clutch S as shown in the drawing, the pawl S05 is in a freely movable state, and power is transmitted. When the convex portion C01 faces, the claw S05 is prevented from moving, and power is not transmitted.

The present invention has achieved the object by skillfully using a relatively inexpensive combination of the spring clutch S and the cam C.

〔Example〕

FIG. 1 shows the configuration of one embodiment of the color image forming apparatus of the present invention. Hereinafter, the present invention will be described with reference to the drawings, but the present invention may have other configurations.

In the figure, reference numeral 10 denotes a drum-shaped image carrier, that is, a photosensitive drum, which is a photosensitive drum having a diameter of 100 mm and an OPC photosensitive layer applied to the peripheral surface of the drum, and driven to rotate clockwise. Reference numeral 20 denotes a band electrode for applying a charge to the photoconductor on the peripheral surface of the photoconductor drum 10, and reference numeral 30 denotes a laser writing system unit as an exposure optical system.

When a color signal output from an image reading apparatus separate from the image forming apparatus is input to the laser writing unit 30, the laser writing unit 30 generates a color signal using a semiconductor laser (not shown). The laser beam is rotated and scanned by a polygon mirror 32 rotated by a drive motor 31 and passes through an fθ lens 33 to three mirrors 34A, 34B, 34C.
The optical path is bent by this, and the light is projected onto the peripheral surface of the photoreceptor drum 10 to which electric charges have been previously applied by the band electrode 20.

On the other hand, when the scanning is started, the laser beam is detected by the index sensor, the modulation of the laser beam by the first color signal is started, and the modulated laser beam scans the peripheral surface of the photosensitive drum 10. Therefore, a latent image for the first color is formed on the peripheral surface of the photosensitive drum 10 by the main scanning by the laser beam and the sub-scanning by the rotation of the photosensitive drum 10. This latent image is developed by a developing device 41 that contains, for example, yellow toner as the first color, and a yellow toner image is formed on the peripheral surface of the photosensitive drum 10.
The obtained toner image passes under the cleaning unit 80 separated from the peripheral surface of the photosensitive drum 10 while being held on the peripheral surface of the photosensitive drum 10, and enters the next copy sille.

That is, the photosensitive drum 10 is charged again by the band electrode 20, and then the second color signal output from the signal processing unit is input to the writing system unit 30, and the above-described case of the first color signal is used. Similarly, writing on the peripheral surface of the photosensitive drum 10 by the second color signal is performed to form a latent image. The latent image is developed as a second color by a developing device 42 containing, for example, magenta toner.

This magenta toner image is formed so as to overlap the previously formed yellow toner image.

The toner image thus obtained passes under the cleaning means 80 separated from the peripheral surface of the photosensitive drum 10 while being held on the peripheral surface of the photosensitive drum 10, and enters a next copy cycle.

Similarly, writing is performed on the photosensitive drum 10 by the third color signal to form a latent image. This latent image is developed by a developing device 43 that contains, for example, cyan toner as the third color. The cyan toner image is formed on the yellow and magenta toner images described above.

As described above, a color toner image is formed on the photosensitive drum 10 by the three color toners. Similarly, by further overlapping the black toner image, a high quality color image can be obtained.

Reference numerals 41 to 44 denote developing units as developing means for storing the yellow, magenta, cyan, and black toners for performing the above-described development, respectively.

As shown in the example of the developing device 41, each of the developing devices is provided with a developing sleeve 41A having a magnetic pole fixed inside and opposed to the peripheral surface of the photosensitive drum 10 with a predetermined gap therebetween, and a developing sleeve 41A in the opposite direction. The rotating developing sleeve 41 is provided with a pair of stirring rollers 41B and 41C having a conveying force, and the developer is made uniform by the toner and carrier components by the mixing action of the stirring rollers 41B and 41C. Is supplied to the peripheral surface.

A DC or further AC bias is applied to the developing sleeve of each developing device that carries the developer, so that non-contact reversal development using a two-component developer is performed.

The charging by the photoconductor drum 10 and the band electrode 20 provided on the periphery thereof and the laser writing unit for each color
The exposure by 30 and the development by the developing devices 41 to 44 are performed four times for each color, so that a color toner image is formed on the peripheral surface of the photosensitive drum 10 by superposition.

50 is a paper feed cassette, 51 is a paper feed cassette with a separating roller
The stacked recording paper in 50 is carried out and fed one by one from the uppermost layer by the action of the separating roller 51.

Reference numerals 52A and 52B denote first and second paper feed rollers which are always rotating, and 53A and 53B denote arc-shaped and linear feed guides, respectively.

The recording paper conveyed out of the paper feed cassette 50 is fed by a first paper feed roller 52A along a paper feed guide 53A, and is turned upside down, ie, turned upside down, and then cuts off the conveyance path of the paper feed guide 53B. The shutter 54 comes into contact with the rising portion and temporarily stops. In this case, the second paper feed roller 52B keeps rotating by slipping on the surface of the stopped recording paper.

When the sheet supply shutter 54 is retracted downward in synchronization with the rotation of the photosensitive drum 10 having the toner image, the recording paper is synchronized with the peripheral speed of the photosensitive drum 10 by the frictional force of the second sheet supply roller 52B. And is fed to the transfer unit 70.

A transfer belt 71 is stretched between the driving roller 72 and the transfer roller 73, and rotates counterclockwise at the same speed as the peripheral speed of the photosensitive drum 10. The transfer belt 71 is driven by a driving roller 72.
The pressure is applied to the photosensitive drum 10 and the pressure is released. That is, the transfer roller 73 is a rotatable roller to which a voltage is applied and is in a charged state.
A transfer unit 70 that transfers a toner image to a recording paper side via a transfer belt 71 at a contact point with the peripheral surface of the photosensitive drum 10 at the time of pressure bonding. Therefore, the transfer is performed while the recording paper is conveyed by the transfer belt 71. Reference numeral 74 denotes a cleaning unit for cleaning the surface of the transfer belt 71.

61 is a front band electrode located upstream of the cleaning device 80,
The toner is charged to a state where the residual toner on the peripheral surface of the photosensitive drum 10 that has transferred the toner image onto the recording paper can be easily removed.

The cleaning device 80 performs pressure bonding and pressure release on the photosensitive drum 10 with the swing shaft 81 as the swing center. 82 and
Reference numeral 83 denotes a conductive cleaning brush and a conductive recovery roller as cleaning means of the cleaning device 80, and reference numeral 84 denotes a waste toner recovery unit for storing the toner recovered by the cleaning means.

The photosensitive drum 10 that has passed through the front band electrode 61 is brought into sliding contact with the cleaning brush by a signal from the control unit.
The residual toner is removed by the 82 and the residual toner attached to the 82 brush is attracted to the collecting roller 83 and then sent to the waste toner collecting section 84.

The waste toner collecting section 84 is provided with a waste toner feed rod 85 and a deformable toner collecting bag 86,
The residual toner, that is, waste toner sent by 83 is stored in the bag member 86 via the waste toner feed rod 85.

The photosensitive drum 10 whose peripheral surface is thus cleaned
Is again charged by the charger 20 to start forming a new image. At the same time, the cleaning brush 82 is released from the rubbing state.

On the other hand, the recording sheet on which the toner image has been transferred in the transfer unit is separated from the peripheral surface of the photosensitive drum 10 and fed to the fixing device. Reference numeral 63 denotes a fixing heat roller pair, and reference numeral 64 denotes a paper discharge roller pair. The recording paper on which the toner is melted and fixed by the heat roller pair 63 is discharged from the fixing device by the paper discharge roller pair 64.

67 and 68 are discharge guides for guiding the recording paper discharged by the discharge roller pair 64 to the upper portion of the apparatus main body, and the recording paper is changed in image surface by a relay of discharge conveyance rollers 65 and 66. Discharged onto tray 69 with face down,
It is laminated.

In the upper right part of the figure, there is a toner supply unit 90. The replenishing section 90 is overlapped on the drawing so that the replenishing toner containers 91, 92, 93, 94
, And yellow, magenta, cyan, and black toners are stored inside for replenishment. The supply toner containers 91, 92, 93, 94 of the same color and the developing devices 41, 42, 43, 44 are connected by toner supply tubes 91A, 92A, 93A, 94A, respectively. A screw is provided inside the toner supply tubes 91A, 92A, 93A, and 94A. When power is transmitted by a signal from the control unit and the screw rotates, the toner in the toner container for supply passes through the supply tube. It is replenished in the developing device.

FIG. 2 shows the positional relationship of the image forming means on the periphery of the photosensitive drum in the color image forming apparatus shown in FIG. 1 described above, and the image forming time of the color image forming apparatus in such a positional relationship is shown in FIG. FIG. 3 shows the chart.

FIG. 4 shows a developing drive device for driving the developing device and supplying toner, and a motor as one cam drive source for selecting a developing device or a toner container for replenishment to be performed. Are shown in a block diagram. This specific embodiment will be described from the driving of the developing device.

FIG. 5 is a perspective view showing a drive system of the developing device. In the figure, 41, 42, 43, 44 are yellow, magenta,
Developing devices of the same or similar structure each incorporating cyan and black toners, and developing devices 41, 42, 43, 44 are provided by rotating gears G41, G42, G43, G44 provided respectively. Each developer is configured to function.

M1 is the developing drive motor, M2 is the cam drive source, and the motor M1 is an AC motor or a motor.
A pulse motor is used for M2. The gear train for developing drive rotated by the motor M1 will be described.
The gear G11 attached to M1 meshes with the gear G12. Gear G1
A gear G13 is provided coaxially with 2, and a solenoid SOL11 is provided between the gear G12 and the gear G13 for switching ON / OFF of the development drive. G13 rotates and gears in OFF state
The rotation of G12 is not transmitted to gear G13.

From the gear G13, the gears G14, G15, G16, G17, G18, G19, G20, G
It is engaged with the series to 21. Gears G14, G16,
G18 and G20 are idle gears provided to make the driving direction of the developing device the same.

There is a gear G41A coaxially with the gear G15, and a gear G15 and a gear G4.
Spring clutch S4 for switching drive connection / disconnection between 1A
1 is provided. Gears G17, G42A and spring clutch S42;
Gears G19, G43A and spring clutch S43; gears G21, G44A and spring clutch S44 have a similar relationship.

The gear G41A meshes with the gear G41. Similarly gear G42A
The gear G42; the gear G43A and the gear G43; the gear G44A and the gear 44 mesh with each other and are connected to the developing devices 41, 42, 43, and 44, respectively.

Looking at cam drive, gears G32, G33, G34, G35, G36,
G37, G38 mesh with the series, and the gear G35 between them meshes with the gear G31 mounted on the shaft of the motor M2.

A cam C41 is coaxially mounted on the gear G32. The cam C41 is a cam that switches the connection facing the spring clutch S41. Gear G34 and cam C42; Gear G36 and cam C43; Gear G3
8 and the cam C44; are coaxial with each other, and the connection is switched to face each of the spring clutches S42, S43, and S44.

FIG. 6 shows the phase relationship between the cams C41, C42, C43, and C44.
It is installed so that there is an angle deviation for ゜.

In the development driving device having the above-described configuration, the motor 1 is turned on at the time of copying, and the solenoid SOL1 is turned on only during the development time.
1 is turned ON, and the cams C41, C42, C43, and C4 which rotate in the same direction at the same time when the development in any of the developing devices is completed.
By driving a motor M2 such as a pulse motor or a rotary solenoid as a cam drive source so that the roller 4 rotates in one direction to 90 °, the development drive shown in the time chart of FIG. An image is formed.

FIG. 7 is a plan view showing the operation of the toner supply unit that supplies toner from the supply toner container to the developing device.
In the drawing, reference numerals 91, 92, 93, and 94 denote replenishment toner containers having the same shape and containing the above-described yellow, magenta, cyan, and black toners. In many cases, the consumption amount of the black toner is larger than that of the toners of other colors, so that the supply toner container 94 may be made large.

The replenishment toner containers 91, 92, 93, and 94 rotate gears G91, G92, G93, and G94 provided on their side surfaces, and the built-in toner is developed through the toner replenishment tubes 91A, 92A, 93A, and 94A. Container 41,
42, 43, 44.

Starting from the gear train for toner supply driving rotated by the common drive motor M1, the gear mounted on the motor M1 shaft
G101 meshes with the gear G102. Gear G102 and Gear G103
Are located coaxially via a spring clutch S90.
And there is a drive solenoid SOL12 on the side of the spring clutch S90 where the protruding / retracting member protrudes, and the spring clutch S90 is disconnected from or disconnected from the power to the gear G103 by turning ON / OFF the current to the solenoid SOL12. The power transmission is switched.

The gear G104 meshing with the gear G103 is a gear fixed to the shaft 101. The shaft G101 is provided with a gear G91A via a spring clutch S91, and the gear G91A meshes with the gear G91. Therefore, the rotation of the shaft 101 is transmitted or not transmitted to the gear G91 by the connection / disconnection of the spring clutch S91. Similarly, the shaft 101 has a gear G92A meshing with the gear G92 via a spring clutch S92; a gear G93A meshing with the gear G93 via a spring clutch S93;
A gear G94A meshing with the gear G94 via the spring clutch S94 is provided, and each functions in the same manner as described above.

Looking at the cam drive, the gear G1 provided on the motor M2 shaft
1 meshes with a gear G12 fixed to the shaft 102. Cams C91, C92, C93, and C94 are fixed to the shaft 102 and face the spring clutches S91, S92, S93, and S94, respectively, and the respective spring clutches are brought into contact or disconnected depending on the phase relationship of the cams. .

The phase relationship between the cams C91, C92, C93 and C94 fixed to the shaft 102 is the same as that shown in FIG.
A cam with the same shape is attached with an angle deviation of 90 °.

The toner replenishing unit having the above configuration rotates a motor M2 such as a pulse motor or a rotary solenoid by a fixed angle, so that only one of the spring clutches S91, S92, S93, and S94 is in a power transmission state. Everything else is in a non-transmitted state. By rotating the motor M2 by the amount that the cam rotates by 90 °, the spring clutch transmitted with the switching of the developing device is switched to the next spring clutch.

At the time of copying, the motor M1 is in the ON state, and the spring solenoid S90 is in the non-transmission state. When it becomes necessary to replenish toner for a specific color, the motor M2 is rotated by a certain angle, and the power is transmitted by the spring clutch opposed to the cam, and the solenoid SOL12 is turned on for a certain time. Then, the gear related to the toner container for supply rotates, and a certain amount of toner inside is supplied to the developing device.

The rotation of the cam drive motor M2 is given priority to the drive of the developing device, the cam rotates by 90 ° for one rotation of the photosensitive drum, and the developing system and the toner replenishing system include, for example, yellow toner. Supply toner container
It is desirable to adopt a configuration corresponding to the cam position from which the toner can be supplied from 91. In such a configuration, when the developing device requires toner supply during development, toner is supplied from the toner supply container.

〔The invention's effect〕

According to the present invention, 3 to 4
In a color image forming apparatus in which a plurality of developing devices are arranged and sequentially driven to form a color image, the driving of the developing devices and the replenishment of toner from the toner replenishing unit to the developing devices are driven. By using a common source and using a spring clutch, drive and drive switching can be performed at low cost, and a toner supply driving device of a color image forming apparatus which is extremely advantageous in cost can be provided.

[Brief description of the drawings]

1 is a cross-sectional configuration diagram of a color image forming apparatus, FIG. 2 is an explanatory diagram showing an arrangement relation of each device in the color image formation apparatus shown in FIG. 1, and FIG. 3 is an arrangement relation shown in FIG. , FIG. 4 is a block diagram showing a drive system for development and toner replenishment, FIG. 5 is a perspective view showing a drive system of a developing unit, and FIG. 6 is an explanatory diagram showing a cam phase relationship. , FIG. 7 is a plan view showing a driving system of the toner replenishing unit, and FIG.
The figure is a sectional view showing the operation of the spring clutch. 10 photoreceptor drum, 20 band electrode 30 laser writing unit 41, 42, 43, 44 developing unit 70 transfer unit 71 transfer belt 73 transfer roller 80 Cleaning means 82 Cleaning brushes 91, 92, 93, 94 Supply toner containers M1, M2 Motors S41, S42, S43, S44; S91, S92, S93, S94 Spring springs C41, C42, C43, C44; C91, C92, C93, C94 …… Cam

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 13/01 G03G 15/01-15/01 117 G03G 13/08 G03G 15/08-15/08 507

Claims (1)

(57) [Claims] A plurality of developing units; and a plurality of toner replenishing units for replenishing toner corresponding to each of the developing units. A developing drive device for a color image forming apparatus that forms a color image by switching driving, comprising: a plurality of developing spring clutches provided corresponding to each of the plurality of developing devices; and a plurality of toner supply units. A plurality of toner replenishing spring clutches provided corresponding to each of the plurality of developing cams; and a plurality of developing cams provided opposite to each of the plurality of developing spring clutches and having uneven portions having different phases. A plurality of toner replenishing cams provided opposite to each of the plurality of toner replenishing spring clutches and having irregularities having different phases, respectively; the plurality of developing devices and the plurality of toner replenishing cams; And a single cam drive source for driving the plurality of developing cams and the plurality of toner replenishing cams, the developing spring clutch and The toner replenishing spring clutch has a claw portion that can be engaged with the developing cam or a convex portion of the toner replenishing cam, and the plurality of developing cams and the plurality of developing cams are driven by the cam driving source. The plurality of toner replenishing cams are rotated to change the positions of the developing spring clutch or the concave and convex portions facing the toner replenishing spring clutch. A developing drive device for the color image forming apparatus, wherein the connection of the developing drive motor to the unit is switched.