JPH0387860A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent wear and defectiveness of a regulating member by providing a supporting plate, which supports the rocking supporting shafts of a developing device, and a disposing an elastic regulating member on the supporting plate. CONSTITUTION:The developing unit 101 of a color selected by allowing a developing device to move a mobile base is turned around the rocking supporting shafts 105R and 105F, in a position where it faces the photosensitive drum of an image carrier and the unit 101 is brought into contact with the photosensitive drum to allow a latent image to be image-formed. After that, the unit 101 turns by self-weight; the external wall of a container 106 is abutted on the elastic stopper member 300 of the position regulating member, and consequently the position of the unit 101 is regulated. Since the member 300 is provided on the supporting plate 123, which supports the shafts 105R and 105F, the member 300 does not slide at the time of regulating the position; the wear and defectiveness of the member 300 is securely prevented, therefore the position of the unit 101 is accurately regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention relates to an image forming apparatus that forms an image on an image carrier using an electrophotographic method or an electrostatic recording method and visualizes the image using a developing device. In particular, the present invention can be suitably implemented in a multicolor image forming apparatus such as a color copying machine or a color printer, which has a developing unit containing a plurality of developers of different colors and is configured to obtain a multicolor image.

Indigo Color Removal 1 Currently, various multicolor image forming apparatuses have been proposed, and a typical example of an electrophotographic color copying machine proposed by the present inventors is shown in FIG.

In the color electrophotographic copying machine of this example, an image carrier 1, which is a photosensitive drum having an electrophotographic photosensitive layer on its surface, is supported rotatably in the direction of arrow X.

A developing device 100 having a primary charger 4 on the left side of the photosensitive drum 1, and a plurality of developing units directly below the photosensitive drum 1, that is, developing units 2M, 2c, 2Y, and 2B in this example, moving in the left-right direction, A transfer device 6 is disposed diagonally above and to the right of the photosensitive drum 1, and a cleaning device 5 is disposed diagonally above and to the left of the photosensitive drum 1.

Further, an optical system 3 is disposed above the copying machine and is configured to project the original image on the platen 26 onto the photosensitive drum 1. Optical system 3 can use any optical system, but
In this example, the first scanning mirror 24, the first scanning mirror 24
from the second and third scanning mirrors 23 that move in the same direction at half the speed of Be configured. Here, the scanner unit 31 is a well-known device that deflects laser light using a rotating polygon mirror, and detailed description thereof will be omitted.

Further, in the optical system 3, the document illumination light source 25 is configured to move together with the first scanning mirror 24. Therefore, the reflected light image of the original scanned by the first to third scanning mirrors 24, 23 passes through the lens 22, is color separated by the BGR color separation filter 35 and the CCD 34, and is converted into an electrical signal. After the signal undergoes information processing such as A/D conversion, it is sent as a video signal to a microprocessor unit (hereinafter referred to as rMPUJ) that controls the entire copying machine. Based on this signal, the MPU oscillates a laser beam from the laser unit via the laser driver,
This laser light starts the copying sequence while ON10F F is applied to the photosensitive drum 1.

Furthermore, a fixing device 18 and a paper feed device 1 are installed on the right side of the copying machine.
5.16 are arranged, and a transfer paper conveyance system 17 is arranged between the transfer drum 6 and the fixing device 18.

In the above configuration, the photosensitive drum 1 includes a primary charger 4, an optical system 36, a developing device 100, and a primary charger 4, an optical system 36, and a developing device 100. Transfer device 6
and is applied by the cleaning device 5.

The developing device 100 includes developing units 2M (magenta developing unit) 2C (cyan developing unit), 2C (cyan developing unit), and 2C (cyan developing unit), which are detachably held on a movable base 120, as will be described in more detail later.
It is equipped with Y (yellow developing unit) and 2B (black developing unit), and each color-separated latent image formed on the photosensitive drum is developed into a toner image by the corresponding developing unit.

The transfer device 6 typically has a transfer material carrying sheet 6a on its peripheral surface.
The transfer drum is configured to electrostatically hold a transfer material, that is, a transfer paper, on the sheet. The transfer drum 6 grips the transfer material, usually transfer paper, fed at the same timing from the paper feeders 15 and 16, and moves it to the transfer position T.
The toner images of each color on the photosensitive drum 1 are rotated and transferred so as to be superimposed and transferred. At the transfer position T, a transfer charger 7 is arranged inside the transfer drum 6.

The transfer paper onto which the toner images of each color have been sequentially transferred is transferred to the transfer drum 6.
It is released from the transfer drum 6 and separated from the transfer drum 6 by the separation charger 8 or the like. The transfer paper is then sent to a fixing device 18 by a transfer paper transport system 17. The toner image on the transfer paper is fixed onto the transfer paper by a fixing device 18, and then the transfer paper is discharged onto a tray 19.

In the copying machine of this example, as is clear from FIG. 2 and the above description, the transfer position T where the toner image formed on the photosensitive drum 1 is transferred to the transfer paper held on the transfer drum 6 is 1, and each developing unit 2M, 2 of the developing device 100
C12Y and 2B are arranged below the photosensitive drum 1.

With such a configuration, leakage from the developing device 100,
Even if some developer is scattered into the machine, the possibility that the scattered developer will adhere to the surface of the transfer drum 6 located above or to the transfer paper is extremely reduced. Also, the developing device 1
00 is located at the bottom of the copying machine main body, it is possible to cover the developing area with a cover 36 or the like to confine the scattered developer in the developing area and prevent it from scattering to the transfer drum installation area.

Furthermore, as described above, since the transfer position T is located above the horizontal line L passing through the center of the photosensitive drum 1, the developer attached to the photosensitive drum 1 scatters and falls toward the transfer drum 6, causing the developer to fall. The risk of contaminating the transfer drum 6 is also reduced, and the cleaner 5 for the photosensitive drum 1 is also located on the side of the transfer drum 6, so that the developer scattered from the cleaner 5 adheres to the surface of the transfer drum 6. Risk is largely avoided.

Furthermore, each of the developing units 2M to 2B of the developing device 100 is mounted on a movable base 120, and is moved in the horizontal direction by, for example, a stepping motor, to a predetermined developing position located approximately directly below the photosensitive drum 1. . Next, a predetermined developing unit is lifted to a developing operating state by a lifting mechanism, which will be described later, and the developing operation is performed by maintaining this state until the development is completed. When the developing operation is completed, the developing unit is lowered, the next developing unit is placed at the developing position, and the developing operation is performed as described above.

The configuration and drive control of such a developing device allows it to be stored in a narrower space compared to a rotary developing device.
The size of the copying machine can be reduced, and the developing unit can be moved or replaced at higher speed.

More specifically, when using a transfer drum with a diameter of 150 mm, for example, placing two sheets of A4 size transfer paper horizontally on the transfer drum and forming an image requires using a rotary developing device. In this case, it would have been extremely difficult to realize this because it would have required a considerable amount of time to replace the developing unit, but it can be achieved extremely easily if a horizontally moving developing device is used as in this example. can. In other words, this means that, assuming that image formation is performed at the same image forming process speed, the copying machine of this example provides twice the productivity.

Next, the developing device 100 used in the color copying machine of this example
will be explained in more detail.

The developing device 100 is configured to be movable in the left-right direction as described above, but the individual developing units need to be arranged directly below the photosensitive drum 1 and close to the photosensitive drum 1 with a predetermined gap therebetween. On the other hand, the developing unit is held directly below the photosensitive drum, that is, at a position retracted from the photosensitive drum l except when it is in the developing operation position.

In this example, developing unit 2 (2M, 2C12Y, 2B
) have the same structure, and the only difference is the color of the developer supplied inside.

Referring to FIG. 3, the developing unit in this example has an elongated developing container 106 whose cross section is approximately rectangular, and the developing container 106 has a magnet (not shown) inside.
A developing sleeve 102 containing a developing sleeve 102 is rotatably supported. Abutting rollers 103 are provided at both end shaft portions of the developing sleeve 102 to ensure a predetermined gap between the developing sleeve 102 and the photosensitive drum 1 . Further, a driving gear 104 for the developing sleeve 102 is fixed to one shaft end of the developing sleeve 102, and the driving force of a motor 125 (FIGS. 4 and 5) is transmitted to the developing sleeve 102 by a drive train described later. .

Further, the magnet within the developing sleeve 102 is positioned at an appropriate position within the developing sleeve 102 by a positioning plate 190 disposed on the other end shaft portion of the developing sleeve.

At both ends of the developer container 106, support shafts 105F and 105R for attaching and positioning the developer unit 2 to a moving base 120 (FIG. 4), which will be described later, are provided on the same axis parallel to the axis of the developer sleeve 102. established in

Further, inside the developer container 106, there is a screw 107.1 (only the shaft part is shown) that stirs and transports the developer contained therein.
08, and the screws 107 and 108 are driven by a drive gear 104 of the developing sleeve 102 via a gear train (not shown). Further, the end of one of the screws (in this example, the screw 107) protrudes from the developer container 106 toward the front side, and passes through a conveyance pipe 160a connected to a toner replenishing device (not shown). Transport vibe 160
At the top of a is a replenishment port 1 for connecting to a toner replenishment device.
60a' is opened in a long shape.

A guide foot 106b (b
,, b-), 106c (see Figures 3 and 8)
is formed so as to be slidably engaged with a slide guide 121 attached to a movable base 120, which will be described later.

FIG. 4 is a perspective view of the entire developing device 100 seen from diagonally above and to the left in front of the copying machine. In this figure, each developing unit 2 is omitted.

The developing device 100 has a movable base 120 on which each developing unit 2 is loaded and moved, and the base 120 has a slide guide 121 (121M) that engages with and holds the guide legs 106b and 106c of each developing unit 2. , 121C11
21Y, 121B) are fixed. As will be described later, cutouts 121M' to 121B' are formed in the middle of each slide guide so that the legs of the developer container can escape when the developer unit swings and approaches the photosensitive drum 1.

Further, the base 120 is provided with a back support plate 122 and a front support plate 123 corresponding to each slide guide 121.

The back support plate 122 has a hole 122' that fits with the rotation support shaft 105R of the developing unit 2, and the front support plate 123 has a hole 123' that fits with the rotation support shaft 105F of the development unit 2. ing. After inserting the developing unit 2 along the slide guide 121 and fitting the rotation support shaft 105R into the hole 122' of the back support plate 122, the front support plate 123 inserts the rotation support shaft 10.
5F and the hole 123' of the front support plate 123 are fitted, and then screwed to the movable base 120.

Here, the back support plate 1 provided for each developing unit of each color.
22 and the holes 122' and 123' in the front support plate 123 are adjusted using a jig or the like during assembly so that they share the same axis parallel to the axis of the photosensitive drum 1.

In this example, the back support plate 122 is screwed to a drive board 124 that supports a drive gear, a clutch, etc., which will be described later, as shown in FIGS. It is fixed to the stand 120 with screws. In addition, the base 120 has a DC
A support plate 126 supporting the motor 125 is fixed with screws.

The movable base 120 is provided with a rail 127 at the rear end of the base 120, and the rail 127 is connected to the bottom plate 60 of the copying machine.
It is slidably engaged with a rail abutment 128 attached to a rear side plate 50 fixed to. On the other hand, the moving base 120
A roller 129 having a built-in bearing is rotatably supported at the front end of the roller 129 via a support plate 130. The rollers 129 are allowed to roll on the bottom plate 60.

With this configuration, the movable base 120 is movable with respect to the bottom plate 60 and the rear side plate 50.

The movable base 120 is driven by the driving force of a stepping motor 132 mounted on the bottom plate 60 by suitable support means (not shown) and gears 133 and 134 also mounted on the same support means. .135 to a rack 131 fixed to the moving base 120.

The developing device 100 having the above configuration is moved toward the photosensitive drum 1 on the movable base 120 in a substantially tangential direction of the photosensitive drum, and is positioned at a predetermined position relative to the photosensitive drum at a developing operation position, that is, a position approximately directly below the photosensitive drum. Positioned with a gap.

Next, the drive train from the DC motor 125 to the developing sleeve 102 will be explained with reference to FIGS. 5 and 6. 6th
This figure is a view of the drive train viewed from the direction of arrow D in FIG. 4, that is, the front direction of the rack 131, and FIG. 5 is a plan view thereof.

The output of the DC motor 125 is rotatably supported by an output gear 150, an idler gear 152 provided on the drive board 124, and further by the drive board 124 and a support plate 155, and the drive is transmitted to the developing sleeve 102 at ON10F. F
is transmitted to clutch gear 153M. Further, the driving force from the clutch gear 153M is transmitted to the gear 157 attached to the drive board 124 via its rotating shaft 154 and output gear 158.

On the other hand, as can be better understood by also referring to FIGS. 3 and 4, for example, the magenta developing unit 2
When M is inserted along the slide guide 121M, the rotary support plate 105R on the back side of the developer container 106 moves to the back support plate 122.
By fitting into the hole 122', the gear 157 and the driving gear 104 of the developing sleeve 102 mesh with each other, as shown in FIG.

For each of the other developing units 2C12Y and 2B, a drive train including clutch gears 153C1153Y and 153B is arranged in the same manner as described above, and each drive train is connected by a relay gear 159 provided on the drive board 124. Driving force is transmitted from the DC motor 125.

Further, when each developing unit 2 is inserted into the slide guide 121, a contact portion (not shown) provided on the movable base 120 for applying a high voltage to the developing sleeve 102 is also connected to the developing unit 2. It is configured to be electrically connected to a similarly provided contact portion (not shown) and a high voltage is applied to the developing sleeve 102 during development, but since such a configuration is well known to those skilled in the art, no further explanation will be given. Detailed explanation will be omitted.

With the above configuration, when the main body of the copying machine is turned on, whether or not the movable base 120 is at the home position can be determined by the light emitting element fixed to the bottom plate 60 and the light receiving element, as shown in FIG. A sensor 181 consisting of an element and a base 12
When the movable base 120 is not at the home position, the stepping motor 132 rotates until the light from the sensor 181 is blocked by the light shielding plate 180, that is,
The moving base 120 is moved until it reaches the home position.

Next, a mechanism for lifting the developing unit will be described with reference to FIG.

In FIG. 7, the movable base 120 and slide guides 121M, 121C1121Y, 121B
is omitted.

A pair of parallel slide guides 121M, 1
21C, 121Y, and 121B, as described above with reference to FIG. Notches 121M' to 121B' for escape
is provided. Further, in the middle of the other slide guide facing the slide guide in which the notch 121' is formed,
A pressing member, which will be described later, presses the container guide foot and lifts the developing unit toward the photosensitive drum, that is, rollers 200M and 2.
00C1200Y and 200B are provided.

On the back side of the movable base 120, as shown in FIGS. 7 and 8, there are roller support plates 201 (201M, 201C120) that constitute a mechanism for lifting each corresponding developing unit.
1Y, 201B) are arranged, and this roller support plate 201 is rotatably supported by a shaft 202 fixedly provided on the back surface of the movable base 120. A shaft 203 is fixed to the roller support plate 201 through the movable base 120.
03, the aforementioned rollers 200M to 200B are rotatably supported.

On the other hand, the shaft 203 is connected to the roller support plate 201 on the movable base 120.
A slotted hole (not shown) is provided in the shaft 203 so that the shaft 203 can rotate together with the shaft 203.

Further, an L-shaped member 204 is fixed to the back surface of the movable base 120, and a rack 205 is arranged on this L-shaped member. The rack 205 functions to transmit the driving force from the pulse motor to the developing unit lifting mechanism.

Next, a description will be given of a configuration in which the developing unit is lifted toward the photosensitive drum by the driving force from the pulse motor.

Referring to FIG. 7, the developing unit lifting mechanism is disposed below the movable base 120, and is housed in a region R formed by molding a part of the bottom plate of the apparatus main body into a concave shape.

Each member constituting the lifting mechanism is fixed to the bottom plate of the main body of the apparatus via a support plate 206.

The lifting mechanism has a drive intermittent member, ie, an electromagnetic clutch 207, equipped with a gear 207a that constantly engages with the rack 205 fixed to the back surface of the movable base 120. The rotating shaft 20g of the electromagnetic clutch 207 is rotatably supported at both ends by a support plate 206 and a one-shaped member 209 fixed to the support plate 206 via bearings. Furthermore, the electromagnetic clutch 20
A gear 210 is provided below the rotary shaft 208 .

The gear 210 includes a shaft 2 fixed to the support plate 206.
Gear 2 via gear 212 rotatably disposed on 11
13 are engaged. The gear 213 is integrally attached to a shaft 214, and the shaft 214 is rotatably supported at both ends by a support plate 206 and a support base 215 fixed to the support plate via bearings. A U-shaped cam plate 216 is integrally attached to one end of the shaft 214 protruding from the support 215.

Further, a shaft 217 is fixedly provided on the cam plate 216 at a position eccentric from the shaft 214 by a predetermined amount. The shaft 217 has a link 2 formed of a slippery member such as resin.
One end of 18 is rotatably fitted. The other end of the link 218 is connected to a shaft 219 attached to one end of the half plate 221.
It is also rotatably fitted. This half plate 221 is
It is rotatable around a shaft 220 fixed to the support plate 215. Further, inside the half plate 221, there is disposed a half plate 222, which is also rotatably provided on the rotation shaft 220 of the half plate 221.

A biasing member (not shown) such as a spring is stretched between the two half plates 222 and 221, and the two half plates 222 and 221 move in the direction of arrow A in the figure. It is being pushed in the direction. The first half plate 222 is regulated at a predetermined position relative to the first half plate 221 by having one end abut against a part of the second half plate 221 .

A shaft 223 is fixedly provided at a portion of the half plate 222 of the second half of the present invention remote from the rotation shaft 220, and a roller 224 is attached to the shaft 223.
is rotatably provided.

This roller 224 comes into contact with the outer surface of the bent portion of the roller support plate 201 formed in the U-shape described above.

Next, a description will be given of how the lifting mechanism configured as described above lifts the developing unit relative to the photosensitive drum.

First, when the main body of the copying apparatus is turned on, the movable base 120 is moved to its home position by the light shielding plate 180 and the sensor 181. In this example, the home position is a position where the distance from directly below the photosensitive drum to the magenta developing unit 2M and the cyan developing unit 2C is equal, that is, the center of the photosensitive drum is located at the center position between the magenta developing unit 2M and the cyan developing unit 2C. state.

When the moving base 120 is at the home position.

FIG. 10 shows the positional relationship between the lifting mechanism installed under the movable base 120 and the roller support plate 201 arranged on the back surface of the movable base 120, viewed from above. The roller 224 in the lifting mechanism is located at the center position between the magenta developing unit 2M and the cyan developing unit 2C at the home position, that is, directly below the photosensitive drum, and is located at the center position between the magenta developing unit 2M and the cyan developing unit 2C, that is, directly below the photosensitive drum. It is in contact with the bent surface of the roller support plate 201C.

Next, a case will be described in which development is performed in the magenta developing unit 2M.

When developing using the magenta developing unit 2M, the movable base 120 moves in the direction of arrow B by a copying (image forming) operation. First move the base 12 by a distance of 24.
0 has moved, that is, from the development position (β/2)−
42, an ON signal is sent to the electromagnetic clutch 207 in the lifting mechanism from the MPU controlling the main body of the device. As a result, as can be understood from FIG. 7, the movement of the movable base 120 is transmitted to the shaft 208 via the rack 205 on the back side of the movable base 120 and the gear 207a that is always engaged with the rack 205. , the shaft 208 is the movable base 12
It starts rotating with the movement of 0. When the shaft 208 rotates,
A gear 210 fixed to this shaft 208 rotates, and this rotation is transmitted to the shaft 214 via gears 212, 213.

The rotation of the shaft 214 causes the cam plate 216 to rotate in the direction of the arrow (FIG. 11). The rotation of the cam plate 216 causes the link 21
8 to the A half plate 221, and the A half plate 221 rotates in the direction of arrow F (FIG. 13).

At this time, since the half plate 222 is spring-biased so as to abut against the half plate 221, it rotates in the direction of arrow G due to the rotation of the half plate 221 (FIG. 13). Therefore,
The roller 224 pushes the roller support plate 201M of the developing unit 2M arranged on the back side of the movable base 120, and the roller support plate 201
M rotates in the direction of arrow H (Fig. 13).

When the roller support plate 201M rotates in the direction of the arrow H, the rollers 200M on the roller support plate 201M move in the direction of the arrow (first
Figure 3). Then, as shown in FIG. 9, the roller 200M moving in the direction of the arrow moves towards the magenta developing unit 2M.
105F and 10 on the movable base 120.
While the base 120 is moving about 5R as a rotational fulcrum, it is lifted in the direction of arrow J, that is, in the direction approaching the photosensitive drum. Then, when the magenta developing unit moves by 2/2, the aforementioned cam plate 216 rotates exactly half a rotation, and the magenta developing unit 2
M is stationary at a position directly below the photosensitive drum 1 and close to the photosensitive drum 1 via an abutment roller 103 .

In the aforementioned lifting mechanism, the gear train 207
a, 210, 212, and 213 are designed so that the cam plate 216 rotates half a turn and stops when the moving base 120 finishes moving.

In other words, the electromagnetic clutch 207 is in the ON state for a distance of 124 = i/2), so
During this distance, the shaft 208 changes the number of teeth of the gear 207a by ZI.
Then, j2'/ (ZI /2
) rad.

Further, if the number of teeth of the gear 210 integrally provided below the shaft 208 is 22, and the number of teeth of the gear 213 integrally provided to the shaft 214 of the cam plate 216 is Z3, then the cam plate 216
While the movable base 120 moves by β', the rotation axis 214 of
= 2f2'ZI /Zl -23(rad)
Rotate a lot.

Therefore, 2℃' Za /z+ @ ZI = i(r
ad) The gear trains 21 to Z3 are designed to be as follows.

Further, there is no particular restriction on the home position of the developing device 100 as long as the center of the photosensitive drum is located between the magenta developing unit 2M and the cyan developing unit 2C.
It goes without saying that the timing for turning on the electromagnetic clutch 207 is set when the developing unit has moved from directly below the photosensitive drum to the front across C'=π·zI−Z3/2z, regardless of the home position.

Furthermore, if the vertical distance between the abutting roller 103 and the photosensitive drum surface is d when the developing unit is not lifted, the amount of lifting of the developing unit toward the photosensitive drum surface is equal to Because it is necessary to press the roller 103 with a predetermined force, the dimensions of the link member 218 in the lifting mechanism are determined so that when the cam plate 216 rotates half a rotation, the value becomes d + α (α: positive number). Figure 11).

Also, the developing unit is placed directly under the photosensitive drum by the abutting roller 103.
When the photosensitive drum approaches the developing unit via α, it receives a reaction force from the photosensitive drum by the amount α, and the developing unit's own weight is pushed back instead. At this time, as mentioned above, the A half plate 222 is connected to the A half plate 221 by a spring.
Since the half plate 222 is biased to rotate toward the photosensitive drum 1, the half plate 222 rotates in a direction away from the half plate 221 of the photosensitive drum 1 against the force of the spring. Ko's half plate 222
When the rotation of the developing unit stops, the developing unit is pressed against the photosensitive drum 1 with a predetermined force via the abutment rollers 103.

With the above operations, lifting of the magenta developing unit 2M is completed.

Next, a case will be described in which the cyan developing unit 2C is lifted after magenta development is completed.

First, it is necessary to separate the magenta developing unit 2M from the photosensitive drum 1 before lifting the cyan developing unit 2C. At this time, as shown in FIG.
6, the link 218 is at the so-called top dead center position with respect to the cam plate 216. Therefore, in order to retreat from this top dead center position, it is necessary to rotate the cam plate 216 slightly by moving the moving base 120.

Therefore, the movable base 120 is moved in the direction C in FIG. 8, and the electromagnetic clutch 207 is kept ON for a very short period of time at the beginning when moving from the magenta developing unit 2M to the cyan developing unit 2C. In other words, if the clutch 207 is turned off when the cam plate 216 is slightly rotated to avoid the top dead center, the cam plate 216 will rotate due to the weight of the magenta developing unit and return to its initial position, and the magenta developing unit 2M will It descends and leaves the photosensitive drum 1.

After that, the cyan developing unit 2C is moved 4 degrees from the developing position.
When the cam plate 216 moves in the direction of arrow C as the movable base 120 moves, the electromagnetic clutch 207 is turned on and the cam plate 216 rotates in the direction of the arrow C. When the magenta developing unit 2M Similarly, the roller 200C on the roller support plate 201C moves in the direction of arrow I (FIG. 13) and begins to lift the cyan developing unit 2C toward the photosensitive drum 1. The lifting movement is completed when the moving base 120 has moved by β/2.

The above-mentioned lifting operation when the magenta developing unit 2M moves in the direction of arrow B (FIG. 11), and the cyan developing unit 2
The lifting operation when C moves in the direction of arrow C (Fig. 12) is as follows:
The same process is performed for each of the other developing units not described.

In other words, according to the lifting mechanism configured as described above, the movable base 1
Even if the developing unit 20 moves in the left-right direction, that is, in the direction of arrow B or C, each developing unit is lifted and positioned very favorably toward the surface of the photosensitive drum.

Although the image forming apparatus having the above-mentioned structure is capable of forming full-color images in an extremely suitable manner, it has the following problems.

That is, as described above, the developing unit 2 has its support shaft 105F.
, 105R as a fulcrum and swings around the fulcrum to move toward and away from the photosensitive drum. When the developing process is completed, the lifting force of the lifting mechanism is released, and the developing unit swings downward due to its own weight and separates from the photosensitive drum. A stopper member is provided as appropriate to determine the lowering position during this lowering. The stopper member is preferably formed of an elastic material such as rubber in order to suppress the generation of noise due to the impact when the developing unit is lowered or the generation of vibrations that affect image blur.

In the conventional image forming apparatus described above, the stopper member is fixed to the movable base 120, and more specifically, for example, a part of the slide guide 121 is formed of an elastic body. It was used as a stopper member.

On the other hand, the developing unit 2 rotates around the support shafts 105F and 105R, descends, and is inserted into and removed from the movable base 120 in a tilted state due to its own weight. Therefore, it is unavoidable that a portion of the developing unit slides on the surface of the stopper member during the insertion/removal operation.

In general, elastic bodies such as rubber have poor surface smoothness due to their nature, and for this reason, when the developing unit is inserted or removed, a part of the developing unit may receive sliding resistance from the stopper member made of the elastic body. Become. As a result, a problem arose in that it became difficult to insert and remove the developing unit from the movable base.

In this way, if the development unit is not attached to or removed from the movable base smoothly, the development unit may be inserted or removed with more force than necessary, which may deform the parts that make up the development unit. Ta.

Furthermore, the stopper member also receives sliding force from the developing unit when the developing unit is inserted and removed, causing problems such as wear or partial breakage.
There are concerns that problems may arise in terms of durability. In this case, furthermore, the positional regulation by the stopper member when the developing unit is rotated and lowered becomes inaccurate. For this reason, the developing unit that has rotated and lowered may collide with an adjacent developing unit or other members placed in close proximity, causing not only noise and vibration, but also Damage to the member that the developing unit collides with is also fully predicted.

Therefore, an object of the present invention is to prevent the stopper member that regulates the position of the developing unit when it is lowered from becoming an obstacle when the developing unit is attached to and removed from the movable base. Image formation that does not cause wear or partial damage to parts, and does not cause noise or vibration, is easy to operate, has excellent durability, and can obtain high-quality images. The purpose is to provide equipment.

To do t ~ first The above object is achieved by an image forming apparatus according to the present invention.

In summary, the present invention provides an image bearing member on which a latent image is formed, and an image bearing member disposed below the image bearing member for making the latent image on the image bearing member visible. and a developing device including at least one developing unit that swings toward and away from the image carrier about a swing shaft and is positioned with respect to the image carrier through an abutting member. In the forming device, supporting a swing shaft of the developing unit;
Further, a support plate configured to be detachably attached to the developing device is provided, and a part of the support plate is made of an elastic body for regulating the position when the developing unit is separated from the image carrier. The image forming apparatus is characterized in that a regulating member is provided.

Part 1 Next, the image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

In this embodiment, the present invention is embodied in the full-color electrophotographic copying machine described in connection with FIGS. 2 to 13, and the structure and operation of the whole and each part are as described above. Therefore, the explanation of the structure and operation of the copying machine will be omitted.

A feature of the present invention is an improved developing unit, and the developing unit will be described below.

Referring to FIG. 1, the developing unit 1 in this embodiment
01 is an elongated developing container 1 having a generally rectangular cross-sectional shape, similar to the developing unit 2 shown in FIG.
06, and a developing sleeve 102 having a built-in magnet (not shown) is rotatably supported by the developing container 106. Abutment rollers 1 are provided at both end shaft portions of the developing sleeve 102 to ensure a predetermined gap between the developing sleeve 102 and the photosensitive drum 1.
03 is provided. Further, a driving gear 104 of the developing sleeve 102 is fixed to one shaft end of the developing sleeve 102, and transmits the driving force of the above-mentioned motor 125 (FIGS. 4 and 5) to the developing sleeve 102.

A developing unit 101 is installed at both ends of the developing container 106.
Support shafts 105F and 105R for mounting and positioning on the movable base 120 (FIG. 4) are provided parallel to and on the same axis as the axis of the developing sleeve 102.

Further, inside the developer container 106, there is a screw 107.1 (only the shaft part is shown) that stirs and transports the developer contained therein.
08 is provided, and the screws 107 and 108 are driven by the developing sleeve 102 (+) drive gear 104 via a gear train (not shown). Further, the end of one of the screws, the screw 107 in this embodiment, protrudes toward the front side of the developer container 106 and passes through the conveyance vibrator 160a connected to a toner replenishing device (not shown). A replenishment port 160a' for connecting to a toner replenishment device is formed in the upper part of the conveyance pipe 160a in the form of an elongated hole.

A conventional developing unit 2 is installed at the bottom of the developing container 106.
Similarly, the guide foot 106b (b.

b 2 ), 106 c (not shown in FIG. 1), etc. are formed, and are configured to slidably engage with a slide guide 121 attached to the movable base 120.

The developing unit 101 constructed according to the present invention further includes a front plate 123 that supports the front support shaft 105F, and in the embodiment shown in FIG. 1, is constructed as a part of the developing unit. A support plate 123' is fixed to the front support plate 123, and a stopper member 300 made of an elastic material such as rubber is disposed at the protruding tip of the support plate 123'.

In the above-described developing device 100 including the developing unit 101 configured in this way, the developing unit 101 is rotated around its support shafts 105F, 105'R and lifted up at the developing position, and in this state, the developing unit 101 is lifted up. The process is carried out.

Next, when the developing process is completed, the lifting force applied to the photosensitive drum 1 from the lifting mechanism is released, and the developing unit 101 rotates around the support shafts 105F and 105R due to its own weight in a direction in which it separates from the photosensitive drum 1. and descend. In the developing unit 101, a part of the outer wall surface of the developing container 106 is connected to the elastic stopper member 3 of the front support plate 123.
The position at the time of descent is regulated at the position where it contacts 00.

As described above, the image forming apparatus according to the present invention includes a part of the front plate integrally formed with the developing unit for regulating the position when the developing unit is rotated and lowered. Since the stopper member made of an elastic body is provided, the problem that occurs in conventional examples is that when the developing unit is moved in and out of the movable base, it is difficult to attach and detach due to the sliding resistance of the stopper member. It will be resolved. Furthermore, according to the present invention, the stopper member does not receive any sliding force from the developing unit when the developing unit is attached or detached, so there is no fear of wear or damage, and the position of the developing unit is always regulated when the developing unit is lowered. This has the advantage that it can be done accurately.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of a developing unit used in an image forming apparatus according to the present invention. FIG. 2 is a configuration diagram of an embodiment of an image forming apparatus that can embody the present invention. FIG. 3 is a perspective view of a conventional developing unit. FIG. 4 is a perspective view of the developing device. FIG. 5 is a plan view illustrating how the developing sleeve of the developing unit is driven. FIG. 6 is a front view seen from direction D in FIG. 4. FIG. 7 is a perspective view of the developing unit lifting mechanism. FIGS. 8 and 9 are front views illustrating the lifting operation of the developing unit. FIG. 10 is a plan view of the lifting mechanism. 11 to 13 are plan views illustrating how the lifting mechanism operates. 1: Image carrier 2.101: Developing unit 6: Transfer drum 100 2: Developing device 120: Moving base 123: Front support plate 300: Stopper member 1 Figure 3 Figure 10

Claims (1)

[Claims] 1) An image carrier on which a latent image is formed, and a rocking support disposed below the image carrier to visualize the latent image on the image carrier. an image forming apparatus comprising at least one developing unit that swings toward and away from an axis and is positioned with respect to the image carrier through an abutting member; A supporting plate is provided that supports a swinging shaft of the developing unit and is configured to be detachable from the developing device, and a part of the supporting plate is provided with a support plate that supports a swinging shaft of the developing unit, and includes a support plate that is attached to a portion of the supporting plate when the developing unit is detached from the image carrier. An image forming apparatus characterized in that a regulating member made of an elastic body is provided for regulating the position of the image forming apparatus.