JP3069741B2 - Color image forming equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus that forms a toner image by developing a latent image on a photoconductor by an electrophotographic method.

[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 periphery of the photosensitive drum and containing developers of different colors, respectively, operate alternately when forming an image, and develop a latent image portion to form a toner image. Since the toner is consumed by the development, if the development is continuously performed without replenishing the toner, when a two-component developer is used, the ratio of the toner in the developer decreases, and a high quality image 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. However, providing a plurality of small motors and performing each control has the disadvantage of increasing the cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color image forming apparatus which is inexpensive and has excellent functions by solving the above problems.

[Configuration of the invention]

The above object is achieved by rotating a plurality of cams provided so that their phases are different from each other by a cam power source in a color image forming apparatus that develops a latent image on a photoconductor to form a toner image. This is achieved by causing a spring clutch selected from a plurality of spring clutches to be in a transmission state, and transmitting the power of one toner supply power source to a toner supply unit corresponding to the selected spring clutch.

[Description of Configuration of the Invention]

As described above, according to the present invention, a spring clutch corresponding to each of a plurality of toner supply units is provided between a power transmission system that transmits power from one toner supply power source to each of the plurality of toner supply units. On the other hand, a cam is provided so as to face the spring clutch, and the cam is rotated by a cam power source,
The opposing spring clutch changes the power of the toner supply power source to a transmission state or a non-transmission state according to the rotation phase of the cam.

FIG. 6 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 shafts S01 and S02. There is a sleeve S04 surrounding the winding 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 scanning is started, the laser beam is detected by the index sensor, modulation of the laser beam by the first color signal is started, and the modulated laser beam scans on 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 expressed by the 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 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 the next copy sille.

That is, the photoconductor drum 10 is charged again by the band electrode 20, then the second color signal output from the signal processing is input to the writing unit 30, and the same as in the case of the first color signal described above. Then, writing is performed on the peripheral surface of the photosensitive drum 10 by the second color signal, and a latent image is formed.
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 is configured. 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 by the fixing device by the paper discharge roller pair 64.

67 and 68 are paper ejection guides for guiding the paper recording paper discharged by the paper ejection roller pair 64 to the upper portion of the apparatus main body. The recording paper is imaged by relays of paper ejection conveyance rollers 65 and 66. Is discharged and stacked on the tray 69 in a state in which is facing downward.

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 pipes 91A, 92A, 93A, and 94A. When power is transmitted by a signal from the control unit and the screw rotates, the toner in the supply toner container passes through the supply pipe. 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 having such a positional relationship is shown in FIG. FIG. 3 shows a chart.

FIG. 4 is a plan view showing the operation of a toner supply unit that supplies toner from a supply toner container to a 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.

M1 is a driving motor for supplying toner, and an AC motor or the like is used. M2 is a cam drive motor, and a pulse motor is used. Starting from the gear train for driving toner supply rotated by the motor M1, the gear attached to the motor M1 shaft
G101 meshes with the gear G102. Gear G102 and Gear G103
Are located coaxially via a spring clutch S90.
There is a drive solenoid SOL12 on the side of the spring clutch S90 in which the protruding / retracting member protrudes and retracts. 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 91 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 93;
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. .

FIG. 5 shows the phase relationship between the cams C91, C92, C93, and C94 fixed to the shaft 102. In each case, a cam having a concave portion C02 of about 90 ° is used to shift the angle of the cam to 90 °. It is installed to hold.

The toner replenishing unit having the above configuration rotates a motor M2 such as a pulse motor or a rotary solenoid at 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 90 ° of the cam, the spring clutch to be transmitted 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 invention's effect〕

According to the present invention, the power of the toner supply power source can be transmitted to any of the plurality of toner supply units by the plurality of cams having different phases from each other. The present invention provides a color image forming apparatus which is inexpensive and has excellent functions, which can be performed by one toner supply power source.

[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 plan view showing a drive system of a toner replenishing unit, FIG. 5 is an explanatory diagram showing a phase relationship of a cam, and FIG. 6 is a sectional view showing an operation of a 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 brush 91, 92, 93, 94 Replenishment toner container M1, M2 Motor S90, S91, S92, S93, S94 Spring clutch C91, C92, C93, C94 Cam

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/01 G03G 15/01-15/01 117 G03G 15/08-15/095 G03G 15/00 550

Claims (1)

(57) [Claims] A color developing device that develops a latent image on a photoreceptor to form a toner image; and a plurality of toner supply units that supply toner from the plurality of toner containers to the plurality of developing devices. In the image forming apparatus, one toner replenishing power source for driving the plurality of toner replenishing units, and setting the power of the toner replenishing power source to a transmission state or a non-transmission state for each of the plurality of toner replenishment units A plurality of spring clutches, a plurality of cams provided so as to switch a transmission state or a non-transmission state of each of the plurality of spring clutches, and to be provided with phases different from each other, and a cam power source for rotating the plurality of cams The plurality of cams rotated by the cam power source cause a spring clutch selected from the plurality of spring clutches to be in a transmission state, and the selection is performed. Color image forming apparatus characterized by transmitting the power of the toner supply power source to the toner replenishing portion which corresponds to the spring clutch.