JPS6285278A - Image forming device - Google Patents

Abstract

PURPOSE:To execute multicolor copying by switching by providing >=1 set of the 1st developing device composed of a single developing device part and >=1 set of the 2nd developing device composed of >=2 developing device parts in one body, and allowing a developing device which is selected by a revolving unit by revolving those developing devices to contact and leave an image carrier. CONSTITUTION:A developing device 14 is equipped with three sets of the 1st developing devices 27a-27c for normal speed copying operation which consist of a single developing device part 100 and one set of the 2nd developing device 27d for fast copying operation which consists of two developing device parts 100 and 100 in one body. Those developing devices 27a-27d are revolved by the revolving device 28 while held in a horizontal state and one developing device is selected. The revolving unit 28 suspended by suspension members 32a and 32b is allowed by a contacting/separating mechanism 62 to contact and leave a photosensitive drum 12 and copying operation is performed by one of the developing devices 27a-27d which is selected by the revolving unit 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an image forming apparatus such as a copying machine capable of making multicolor copies, for example.

[Technical background of the invention and its problems] In recent years, a high-speed image forming apparatus that requires time for development has been developed (Japanese Unexamined Patent Publication No. 57-661). Since it is necessary to carry out the phenomena simultaneously in a steamer, there is not enough space around the photosensitive drum to accommodate developing devices for other colors, making it impossible to perform multicolor automatic switching copying.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its object is to provide an image forming apparatus capable of performing high-speed copying and multicolor switching copying.

[Summary of the Invention] In order to achieve the above object, the present invention provides an image forming apparatus that develops a latent image on an image bearing member. At least one developing unit is provided, and the second developing unit is integrated with the developing unit, and the first developing unit and the second developing unit are caused to revolve while being maintained in a parallel state at a position apart from the image carrier. The present invention is characterized in that a developing device is selected and the selected developing device is brought close to the image carrier to perform the phenomenon.

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

FIG. 16 and FIG. 1 show a multicolor copying machine as an image forming apparatus according to the present invention, and numeral 1 in these figures is the main body of the copying machine. A document table 2 on which a document is placed is fixed to the upper surface of the main body 1.

The original set on the document table 2 is exposed and scanned by an optical system consisting of an exposure lamp 3 and a mirror 4, 5, and 6 reciprocating along the lower surface of the document table 2. It has become so. In this case, mirror 5
．． 6 is 1/2 of the mirror 4 to keep the optical path pressure constant.
move at a speed of The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the light irradiation of the exposure lamp 3, is reflected by the mirrors 4, 5.6, passes through the lens blocker for setting the copying magnification, and then passes through the lens blocker for setting the copy magnification. The light is reflected by mirrors 8,9,10 and guided through slits 11 to a photoreceptor drum 12 as an image carrier, so that an image of the document is formed on the surface of the photoreceptor drum 12. The photosensitive drum 12 rotates in a predetermined direction,
First, the surface is charged by the charger 13, and then the image of the document is exposed to slit light to form an electrostatic latent image.
It is configured to be visualized by adhering toner by M14.

On the other hand, sheets p are taken out one by one from the sheet cassette 15 by the sheet feed roller 516, guided through the sheet guide path 17 to a pair of registration rollers 18.18, and aligned by the registration rollers 18.18. The image is configured to be sent to an image transfer section. The paper feed cassette 15 is detachably provided at the lower right end of the main body 1. The paper p sent to the image transfer section comes into close contact with the surface of the photoreceptor drum 120 at the transfer charger 19, and the toner image on the photoreceptor drum 12 is transferred by the action of the charger 19. be done. The toner image onto which the toner image has been transferred is electrostatically peeled off from the photoreceptor drum 12 by the peeling charger 20, conveyed by the conveyor belt 21, and sent to the fixing device 22 provided at the end of the conveyor belt 21. The transferred image is fixed by passing through this area. The sheet p after fixing is configured to be discharged to a tray 24 outside the main body 1 by paper discharge rollers 23,23. Further, the photosensitive drum 12 after the transfer is configured so that residual toner on the surface thereof is removed by a cleaner 25, and then the residual image is erased by a static elimination lamp 26, so that the image returns to the initial state.

The developing device 14 includes three first developing devices 27a to 27c for normal speed copying consisting of a single developing device section 100, and a first developing device 27a to 27c for high speed copying consisting of two integrated developing device sections 100 and 100. One second developing device 27d is provided, and by causing each of these developing devices 27a to 27d to revolve while maintaining a parallel state B (horizontal state B) by a revolution unit 28, one developing device (1fi27a to 27d) can be created. This current 111 device 14 can be selected.
The i-mechanism 29 allows it to move in the left-right direction (direction toward and away from the photoreceptor drum 12). That is, during the copying operation, as shown in FIG.
27d are set in a state fi in which they are set opposite to the photoreceptor drum 12 (near the photoreceptor drum 12), and when the developing units 27a to 27d are selected, as shown in FIG. The developing devices 27a to 27d are moved to a position a predetermined distance away from the developing device 12, and the selection operation of the developing units 27a to 27d is performed at this position. When this selection operation is completed, the developing units 27a to 27d are moved to the photosensitive drum 12 side again, and the selected developing devices 27a to 27d are set opposite to the photosensitive drum 12, as shown in FIG. Become.

Next, the developing device 14 will be explained in detail.

As shown in FIG. 3, the main body frame 30 has a support shaft 31.
A pair of suspension members 32a and 32b are swingably suspended via a pair of suspension members 31, and the above-mentioned revolution unit 2 that revolves the developing devices 27a to 27d is attached to the suspension members 32a and 32b.
8 is supported.

That is, as shown in FIGS. 3 and 4, a shaft 33 is rotatably installed between the suspension members 32a and 32b, and a front rotating frame is provided between the suspension members 32a and 32b of the shaft 33. 34ai! 3 and a rear rotating frame 34b are fixedly provided, and an auxiliary frame 35 is provided roughly between the front rotating frame 34a and the suspension member 32a. Moreover, between the front side rotating frame 34a and the auxiliary frame 35, rotating shafts 36a to 3 are provided.
6d is rotatably arranged via a bearing (see FIG. 7), and receivers 378-37d are provided on the rear rotating frame 34b in correspondence with the rotating shafts 368-36d. Developing devices 27a to 27d are installed between these rotating shafts 36a to 36d and receiver portions 37a to 37d via front side coupling portions 38a# and rear side coupling portions 38b, respectively, which will be described later. It has become. Then, the selection motor 39 fixed to the suspension member 32a selects the pulley 40, timing belt 41,
The above-mentioned Freon! is sequentially passed through the pulley 42 and shaft 33. - Side rotating frame 34a and rear rotating frame 3
4b is rotationally driven, the developing units 27a to 27d
revolves around the shaft 33.

Further, a holding mechanism 43 is provided between the rotating frame 34a and the auxiliary frame 35 to hold the rotating shafts 36a to 36d so that the developing devices 27a to 27d are oriented in a fixed direction. That is, a sun pulley (fixed pulley) 44 is fitted between the front 1-side rotating frame 34a of the shaft 1-33 and the auxiliary frame 35, and this is fixed to the suspension member 32a. , shaft 33
It is rotatable relative to the main body 11111, but is fixed relative to the main body 11111. That is, the front rotating frame 34
a, rear rotating frame 34b and auxiliary frame 35
Even if the sun pulley 44 rotates, the sun pulley 44 does not rotate. Furthermore, planetary pulleys (revolving pulleys) 45a to 45d are fixed between the front frame 34a and the auxiliary frame 35 of the rotating shafts 36a to 36d, respectively. In addition, the sun pulley 44 and the planetary pulleys 45a, 4
The timing belt 46 is connected between the sun pulley 44 and the T1W pulleys 45c and 45d.
7 are crossed each. However, solar pulley 4
4 and each planetary pulley 45a to 45d have the same outer diameter, and when the front rotating frame 34a and the rear rotating frame 34b rotate, the planetary pulley 45a
~45d revolves without rotating. Therefore, the developing units 27a to 27d always revolve at the same angle, that is, while maintaining a parallel state. This is the developing device 27a.
This is a necessary operation because powder toner is contained in the area 27d.

Here, it is assumed that, for example, red 1-toner is stored in the developer 27a, blue toner is stored in the developer 27b, green toner is stored in the developer 27C, and black toner is stored in the developer 27d. .

As shown in FIG. 5, the rear side coupling portion 38b has a structure in which a bearing 49 that fits into a shaft 48 protruding from the rear side of the developing units 27a to 27d is biased toward the front side by a spring 50. ing. In addition, spring 5
0 is fixed by a holder 51 to the portions 37a to 37d of the rear rotating frame 34b.

The front side coupling portion 38a is as shown in FIGS. 6 and 7. That is, the rotating wheel 3
A holder 52 is fixed to each of 68 to 36d, and this holder 52 is provided with a U groove portion 54 that slidably and rotatably supports a shaft 53 protruding from the front side of the developing devices 27a to 27 (j). Also, this holder 5
2 is provided with a groove 56 having a recess 55 .
A lever 59 having a shape is rotatably fitted therein.

By fitting the locking pieces 58 into the recesses 55, the angle of the lever 59 is held at three levels. A cam 61 is connected to the lever 59 via a shaft 60, and the cam 61 has a large diameter portion 61a that presses the shaft 53 toward the rear side. Further, this cam 61 is provided with a stopper portion 61b and a rotation stopper portion 61c that fit into the groove 538 and mill cut portion 53b provided in the shaft 53 to prevent the shaft 53 from slipping out and from rotating. .

Therefore, in order to install the developing units 27a to 27d, first, the rear shafts 48 of the developing units 27a to 27d are fitted into the four bearings of the rear side coupling portion 38b, and in this state, the developing units 27a to 27d are mounted. While pressing toward the rear side, the front shafts 53 of the developing devices 27a to 27d are inserted into the U groove portion 54 of the front coupling portion 38a. At this time, the five levers are in the state shown in FIG. 7(a). From this state, the lever 59 is brought into the state shown in FIG. 7 (b), and the end of the shaft 53 is
It abuts against the stepped portion 54a of the groove portion 54 to perform axial positioning. In this state, the developing devices 27a to 27d are connected to the rotating shaft 3.
Therefore, when changing the angle of the developing devices 27a to 27d, it is only necessary to put five levers in this state. Next, the lever 59 is further pushed down to the state shown in FIG. 7 (c), and the shaft 53 is
A retaining portion 61b is provided in the groove 538 of the milling cut portion 53.
The rotation prevention portions 61G are fitted into the holder 52, respectively, to prevent the shaft 53 from rotating as shown in FIG. 7(c). In this state, the installation of the developing devices 27a to 27d is completed.

The revolution unit 28 suspended by the suspension members 32a and 32b is brought into contact with and separated from the photoreceptor drum 12 by the contact mechanism 62, as shown in FIGS. 8 to 10. ing. That is, the suspension member 32a,
Arms 63a, 63 are provided near the lower end of each of the arms 32b.
[) are arranged to be substantially perpendicular to the suspension members 32a, 32b. A long hole 64 is formed in the arm 63a, 63b opposite to the photoreceptor drum 12, and extends in a direction toward and away from the photoreceptor drum 12, and a bushing 65 is rotatably and movably attached to the elongate hole 64. ing.

Further, this pusher 765 is biased by a spring 66 and pressed toward the photosensitive drum 12 side. Further, a connecting pin 67 fixed to the suspension members 32a and 32b is rotatably fitted into the hole of the bush 65.

Also, the photosensitive drums 121 of the arms 63a and 63b! !
A bearing 68 is fitted into 1, and this bearing 68
via bin 69, link 70. A crank mechanism section 72 made up of a shaft 71 is connected.

Further, the shaft 71 is rotatably held by the main body frame 30, and torque from a motor 76 is transmitted to the shaft 71 via a pulley 73, a timing belt 74, and a pulley 75. The rotation of the motor 76 causes the revolution unit 28 to move toward and away from the photosensitive drum 12 .

Therefore, as shown in FIG. 11(A), when the revolving unit 28 is located at the developing position close to the photosensitive drum 12, the center of gravity of the revolving units 28 to 28 is located approximately directly below the support shaft 31. It becomes. That is, the line connecting the support shaft 31 and the shaft 33 is approximately perpendicular, in other words, the revolution unit 28
The vector of gravity applied to the shaft 31 is positioned so as to pass through the support shaft 31. Also, at this time, the bushing 65 is pressed toward the photosensitive drum 12 by the spring 66 without touching either end of the elongated hole 64, and the bushing 65 is pressed against the photosensitive drum 12 by the spring 66. 7a to 27 (j is each developing device 27
Parts of a to 27d abut against a positioning portion (not shown) provided on the main body frame 30, so that the distance from the photosensitive drum 12 is kept constant. In addition, in this state, the bin 69 is the closest to the photoreceptor drum 1.
The motor 76 is rotating so as to face the second side.

Furthermore, when the motor 7G starts rotating from this state,
The left end of the elongated hole 64 touches the Pushshikoro 5, and the revolving unit 1-
28 begins to separate from the photoreceptor drum 12. When the motor 76 further rotates, the suspension members 32a and 32b tilt, and as shown in FIG. 11(b), the revolving unit 28
is separated from the photoreceptor drum 12 and placed in a position where it can revolve.

The first developing devices 27a to 27c are constituted by a single developing device section 100, as shown in FIG. That is, the developer case 81 contains developer G, which is a mixture of toner T and magnetic carrier C in an appropriate ratio. This phenomenon agent G is conveyed by a magnet roller 82 containing a built-in magnet, and is transported by a doctor blade 83.
After the layer thickness is regulated to a predetermined layer thickness S, the photoreceptor drum 12
The electrostatic latent image formed in advance on the photoreceptor drum 12 is thereby developed. Further, 84 is a stirrer, which mixes and stirs the toner T, which is replenished when the toner concentration in the developer G decreases, and the developer G, and maintains the toner concentration in the developer G uniformly. be.

A toner hopper part 85 storing toner T to be replenished is provided at the upper part of the developing device case 81, and the toner hopper part 85 is supplied to the developing device case through a toner replenishing port 87 by rotation of a toner replenishing port row 586. The 1-ner T is supplied onto the stirrer 84 inside the stirrer 81.

On the front side of the first developing units 27a to 27c, as shown in FIG. The above current @O-
An agitator gear 91 that meshes with the lug gear 89 is provided. On the other hand, a developing unit drive motor 92 and a developing unit driving gear 93 driven by the developing unit drive motor 92 are provided on the main body 1 side, and the selected developing units 27a to 27c of the developing device 14 approach the photosensitive drum 12. When the developer drive gear 93
meshes with the magnet roller gear 89, so that the magnet roller gear 89 and the Wt stirring steamer gear 91 are driven. Note that 94 is a replenishment roller drive gear for driving the toner replenishment port 586.

The second current unit 27d is, as shown in FIG.
The developing device sections 100, 100 are integrally constructed.

In other words, there are two developing units 1 in the developing unit case 101.
00 are provided in two stages, upper and lower, and the upper and lower developing device portions 100 and 100 each contain developer G, which is a mixture of toner T and magnetic carrier C in an appropriate ratio. This developer G is conveyed by magnet rollers 102 and 103 containing a built-in magnet, and after being regulated to a predetermined layer thickness by a doctor blade 104 and 105, it is supplied onto the photoreceptor drum 12. An electrostatic latent image previously formed thereon is adapted to be developed. Further, reference numerals 106 and 107 denote agitators, which mix and stir the toner T and the developer G, which are replenished when the toner S level in the developer G decreases, to make the toner concentration in the developer G uniform. It is to be maintained.

The lower part of the developer case 101 is shown below! A toner hopper portion 108 storing toner T is provided at the upper part of the container section 100 and adjacent to the upper developing device section 100.
This toner hopper part 108 is connected to the toner supply roller 10
The rotation of 9 replenishes toner T onto the agitator 106 in the lower developing unit 100 through the toner replenishment port 110, and the rotation of conveyors 1 to 2 replenishes the toner T onto the agitator 106 in the upper developing unit 100. Toner T is supplied onto the stirrer 107.

On the front side of the second developing device 27d, as shown in FIG.
agitator gears 118, 119 attached to 6, 117;
An intermediate gear 120 for interlocking the magnet roller 103 with the magnet roller 102, and a magnet row 510.
Intermediate gear 12 for interlocking agitator gear 107 with 3.
1 is arranged. Then, the developing device 2 of the developing device 14
7d is selected and approaches the photosensitive drum 12, the developer drive gear 93 meshes with the magnet roller gear 114, and the magnet roller gear 114, 115 and the agitator gear 118, 119 are driven. .

Note that 122 is a replenishment roller drive gear for driving the toner replenishment roller drive gear 108, and 123 is a conveyor drive gear for driving the toner replenishment conveyor 111.

The process speed is faster when the second developing device 27d is set than when the first developing devices 27a to 27c are set.

Next, a copying operation in such a configuration will be explained. First, if a document is set on the document table 2 and, for example, a black copy is to be made, the developing device 14 is first removed from the photoreceptor drum 12 in order to select the second developing device 27d containing black toner. Move it away (to the right). When the movement of the developing device 14 is completed in this way, the selection motor 39 is operated to rotate the rotating frames 34a and 34b, so that each developing device 27a is moved as described above.
- 27d are caused to revolve while maintaining a parallel state, and when the developing units 27a to 27d to be selected are opposed to the photosensitive drum 12, the revolution operation is stopped. When this operation is completed, the developing device 14 is moved to the photosensitive drum 12 side, and
The selected developing devices 27a to 27d are set close to the photosensitive drum 12 so as to face each other. With the above operation,
This means that the selection operation of the developing device 27d corresponding to the selected and designated color has been completed, and black copying is now possible.

Next, the copying operation is started, and black copying is performed at a process speed corresponding to the second developing device 27d, that is, a fast process speed. That is, exposure is performed as the original is scanned, and the electrostatic latent image formed on the photoreceptor drum 12 by this exposure is visualized by the two magnetic rollers of the second developing device 27d, and the developed image is The converted dove image is transferred onto the supplied paper ρ. Next, the paper p on which the toner image has been transferred is sent between the heat rollers 22 and 22 by the conveyor belt 21, and is pressed and fixed.

The fixed paper p is discharged onto the tray 24 by the paper discharge rollers 23, , 23. High-speed copying is performed as described above.

Note that when the first developing devices 27a to 27c are selected, normal copying is performed using the second developing device 27d at a process speed that is slower than 7 times.

According to the above configuration, the single developing device section 100 includes the first developing devices 27a to 27c and the two side developing device sections 100.1.
A second developing device 27d in which 00 is integrated is provided, and these first and second developing devices 27a to 27dl! ! The 1g developing units 27a to 27d are selected by rotating them while maintaining the parallel state at a position apart from the photosensitive drum 12, and the selected developing units 27a to 27d are brought close to the photosensitive drum 12 to perform development. This makes it possible to perform high-speed copying using the second developing device 27d and multicolor switching copying by switching between the first and second developing devices 27a to 27d.

[Effects of the Invention] As described above, according to the present invention, in an image forming apparatus that develops a latent image on an image bearing member, at least one first developing unit consisting of a single developing unit; At least one second developing device is formed by integrating at least two developing device parts, and one developing device is formed by rotating the first and second developing devices while keeping them in a parallel state. Since it is equipped with a rotating unit for selection and a mechanism for moving the developing device selected by the rotating unit toward and away from the image carrier, it can achieve effects such as high-speed copying and multi-color switching copying. play.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view schematically showing the state of the main body during copying operation, and FIG. FIG. 3 is a side view of the revolution unit, FIG. 4 is a front view of the revolution unit, FIG. 5 is a perspective view of the rear coupling section, and FIG. 6 is a perspective view of the front coupling section. , Figures 7(A) to (C) are explanatory diagrams of the operation of the front side coupling part, Figure 8 is a perspective view showing the developing device, Figure 9 is a front view showing the developing device, and Figure 10 is the approach and separation. Diagram showing the mechanism,
Figures 11 (a) and (b) are explanatory diagrams of the operation of contact and separation @even, and Figure 12
13 is a perspective view showing the drive system of the first developing device, FIG. 14 is a vertical sectional view of the second developing device, and FIG. 15 is a vertical sectional view of the second developing device. a perspective view showing a drive system of a developing device;
FIG. 16 is a partially cutaway perspective view of the main body. 12... Image carrier (photosensitive drum), 27a-27c
...First developer, 27d...Second developer, 28
...Revolving unit, 62...1 approach and separation, 100...
・Developer section. Applicant's representative Patent attorney Takehiko Suzue Figure 3 Figure 9 Figure 10 (a) Figure 11 Figure 12 Figure 13 Figure m 14 Figure m 15 Figure 16

Claims (1)

[Claims] In a device that develops a latent image on an image carrier, at least one first developing device is composed of a single developing device section, and at least one first developing device is composed of at least two or more developing device sections. By rotating the second developing device and the first and second developing devices while keeping them in parallel,
1. An image forming apparatus comprising: a revolution unit that selects a developing device; and a contact/separation mechanism that brings the developer selected by the revolution unit into and away from an image carrier.