JPH0746242B2 - Rotary developing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrostatic latent image formed on a latent image carrier having a plurality of developing devices containing a developer and each developing device occupying a predetermined developing position. So that the development operation to visualize the
The present invention relates to a rotary developing device including a developing unit rotatably supported so as to face a latent image carrier.

2. Description of the Related Art For example, a developing device of the above type used in an image forming apparatus such as a copying machine or a printer is well known. In this type of developing device, a developing device having a function of visualizing a latent image with a developer is selectively rotated and positioned at a specific developing position around the latent image carrier to form an electrostatic latent image. Visualize. Since the developing device must be rotated to the developing position in this way, it is necessary to rotatably support the developing unit itself. For this purpose, in a conventional developing device, a support shaft protruding outward is provided at the center of each end wall that defines both ends of the developer chamber of the developing device, and these support shafts are rotatably supported by bearings. Was. However, when the various elements of the developing device or other devices are arranged outside the end wall of the developing unit, the space for arranging the bearing for the support shaft is taken away by these elements, and the support shaft is provided on the end wall of the developing unit. It is not possible to adopt a structure of supporting by bearings. For example, if a toner supply device that supplies toner to the outside of the end wall of the developing unit is provided, a plurality of toner supply pipes will protrude outward from the end wall, and a bearing for a spindle will be provided by these supply pipes. There is no more space to install and bearings cannot be placed.

The present invention has been made based on the above recognition, and even when various elements are arranged outside the end wall of the developing unit, the developing unit can be rotatably supported without trouble and the cost is increased. It is an object of the present invention to provide a developing device of the type described at the beginning that can minimize the above.

To achieve the above object, the present invention forms the outer peripheral surface of at least one of the two end walls that define both ends of the developer chambers of the plurality of developing devices in the developing unit into a cylindrical shape, A configuration is proposed in which at least two points on the outer peripheral surface are rotatably supported by support pieces.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

The rotary developing device shown in FIG. 1 has a developing unit 1 which is supported by a copying machine main body 2 so as to be able to be pulled out as will be described later (when the developing unit 1 is pulled out from the copying machine main body 2, (See Figure 4). The developing unit 1 has a plurality of developing units 3, 3R, 3B in the illustrated example, and the developer chambers 4, 4R, 4B of the developing units 3, 3R, 3B are made of non-magnetic material such as aluminum. Three partition walls 6,6R, 6 of the casing member 5 consisting of a body
It is divided by B and two end walls 7 and 8 (see FIGS. 2, 3, and 4) fixed to each end in the longitudinal direction. Each developer chamber 4, 4R, 4B has a different color developer 9, 9
R and 9B are contained, and in this example, each of these developers is black, red, and blue. Cyan, yellow and magenta toner developers are stored in each developer chamber,
It can be configured to form a full-color image, or the developers of the same color can be contained in each developer chamber, and these can be used selectively or as spares. Although a one-component developer containing no carrier can be used as the developer, a two-component developer containing a carrier and a toner, at least a part of which is a magnetic material, is used in the example shown in the figure. Is used. Although the first to third developing units 3, 3R, 3B are arranged radially around the central axis O of the developing unit 1, since the images are all the same, the first and third developing units will be mainly described below. The configuration of the developing device 3 of No. 1 is clarified, and the parts attached to the other developing devices 3R and 3B are denoted by R in the reference numerals attached to the respective elements of the first developing device 3.
, And B, and the duplicate description is omitted. The same applies to the toner supply devices described later that belong to the developing devices 3, 3R and 3B, respectively.

As will be described later, the developing unit 1 is rotatably supported around its central axis O, and each developing device (more precisely, a developing roller described later) rotates to a predetermined developing position to perform a developing operation. FIG. 1 shows a state in which the first developing device 3 occupies the developing position.

In FIG. 1, a developer transport member provided in the first developing device 3, the developing roller 10 in the illustrated example, is partially exposed from an opening formed by two partition walls 6 and 6R (see also FIG. 4). reference),
The developing roller 10 occupies a predetermined developing position with respect to the latent image carrier rotatably supported by the copying machine main body 2, in this example, the photoconductor drum 11 (latent image carrier comprising a photoconductor belt). It is well known that a latent image carrier composed of a dielectric belt or a dielectric drum is used depending on the type of the image forming apparatus). At that time, the developing roller 10 is positioned parallel to the photosensitive drum 11 with a predetermined minute gap. As can be seen from FIG. 3, the developing roller
Both support shafts 12 and 13 of 10 are rotatably supported on both end walls 7 and 8 of the developing unit 1, respectively, and are located at the inner side of the copying machine main body 2 (see FIG. 2,
One support shaft 13 (on the left side in FIG. 3) penetrates the end wall 8 and a developing roller gear 14 is fixed to the tip thereof.

An impeller 16 having a large number of blades 15 is provided inside the developer chamber 4.
Is placed, and this impeller 16 is internally provided in the boss portion 32,
And a feed screw shaft parallel to the developing roller 10.
The screw shaft 17 is attached to the impeller 16 integrally.
Is driven to rotate counterclockwise in FIG. As a result, the developer in the developer chamber 4, that is, the toner and the carrier are supplied to the developing roller 10 while being stirred, and the toner is frictionally charged to a predetermined polarity by the stirring of the toner and the carrier. A screw 18 is formed on the feeding screw shaft 17 over substantially the entire length thereof.

It corresponds to one end of the feed screw shaft 17, that is, the back side of the copying machine main body 2. As shown in FIG. 2, the left and right ends rotatably penetrate the end wall 8 of the developing unit 1, and the feed gear 19 is fixed to the tip end of the end wall 8.
It is driven to rotate with 16. In addition, screw shaft 17
The other end, that is, the front end of the main body of the copying machine penetrates through the inside of the supply pipe 20 fixed to the hole of the developing unit end wall 7,
It is rotatably instructed to 20. In this example, the feed screw shaft 17 and the supply pipe 20 constitute a developer carry-in means for supplying the developer to the developer chamber 4.

Inside the developing roller 10, a magnet 21 having a magnetic pole composed of an S pole and an N pole is fixedly arranged on the casing member 5 of the developing unit 1 as indicated by S and N in FIG. As a result, when the developing roller 10 is rotationally driven counterclockwise in FIG. 1 via the developing roller gear 14, the developing roller 10 is rotated.
The magnetic developer 9 supplied to the carrier 10 is carried on the surface of the developing roller 10 by the magnetic force of the magnet 21 and is conveyed counterclockwise.
The transported developer is scraped by the doctor blade 22 fixed to the casing member 5,
A predetermined amount of the developer that has passed through 22 is regulated in layer thickness and is sent toward the photoconductor drum 11.

On the other hand, the photosensitive drum 11 is driven to rotate clockwise in FIG. 1, and an electrostatic latent image corresponding to an original (not shown) image is known on its surface by charging / exposure means not shown. Is formed. When this latent image reaches the opposing developing area D between the photoconductor drum 11 and the developing roller 10, the charged toner in the developer also conveyed to this area D is electrostatically transferred to the electrostatic latent image to form the latent image. Is visualized. Since the color of the toner of the first developing device 3 is black, the visible image in this case is also black. The visible image is transferred onto a transfer paper (not shown) by a transfer device (not shown), and the transferred visible image is fixed by a fixing device (not shown). The developer that has passed through the developing area D is returned to the inside of the developer chamber 4 again, mixed with other developers in this chamber, and used again.

The developer scraped off by the doctor blade 22 is guided by the guide member 23 in the direction indicated by the arrow B, and is conveyed to the delivery screw shaft 24 parallel to the delivery screw shaft 17, a part of which is described below. Screw shaft
24 is transported to the outside of the developer room, and other developer is
Guide member 23 as indicated by arrow C in FIGS. 3, 3 and 3a
It flows upward, flows down to the impeller 16 located at the bottom of the developer chamber 4, and is agitated.

As can be seen from FIGS. 1 to 3a, the guide member 23 has a gutter-shaped portion 25 that covers substantially the lower half of the feed screw shaft 24, and each end of the guide member 23 has an end wall 7 of the developing unit 1. ,
It is fixed to 8 respectively. Sending screw shaft 24
One end portion (the left end portion in FIG. 2) is rotatably supported by the end wall 8 on the back side, penetrates this end wall 8 and drives the feed-out screw shaft 24 to the most distal end thereof. The feeding gear 26 for fixing is fixed. In addition, the feed screw shaft 24
The other end portion (the right end portion in FIG. 2) of the pipe 27 penetrates through the inside of the discharge pipe 27 fitted and fixed in the hole of the end wall 7 on the front side.
It is rotatably supported by. Sending screw shaft 24
A screw 28 is also formed, and this screw 28 may be formed over the entire length of the screw shaft 24, but in the example shown in the figure, the shaft portion fitted to the discharge pipe 27 and the inside of the developer chamber The screw 28 is formed only on a part of the shaft portion.

As shown in FIG. 3a, both flange portions 29 of the guide member 23
A large number of guide fins 30 straddling the delivery screw shaft 24 are fixed to the guide fins 30, and these guide fins 30 extend obliquely as shown in FIG. 3a. For this reason, as described above, the developer scraped off by the doctor blade 22 and flowing on the guide member 23 is guided by the guide fins 30 in the direction of arrow C, that is, from the direction orthogonal to the axial direction of the developing roller 10 by α (first Three
(Fig. And Fig. 3a) are guided in the inclined direction C and fall to the bottom of the developer chamber 4 as described above. In this way, the developer flows on the guide member 25 while being displaced in the direction perpendicular to the paper surface of FIG. 1, so that the carrier and the toner are effectively stirred.

Further, the developer that has flowed from the doctor blade 22 to the screw 28 portion of the screw shaft 24 is fed by the delivery gear 26.
By the screw 28 of the feed screw shaft 24 which is rotationally driven via the, the sheet is conveyed rightward in FIG. 2, that is, toward the front side of the copying machine main body while being guided by the gutter-shaped portion 25 and the discharge pipe 27, and is developed. It is discharged to the outside of the unit end wall 7. In this way, the delivery screw shaft 24, the gutter-shaped portion 25, and the discharge pipe 27 constitute the developer delivery means in this example.

As shown in FIG. 2, the discharge pipe 27 and the above-mentioned supply pipe 20 communicate with each other via a connecting pipe 31 which will be described in detail later. Therefore, the developer conveyed in the discharge pipe 27 as described above is indicated by an arrow E. A feed screw shaft that flows into the feed pipe 20 through the connecting pipe 31 as shown, and is then driven to rotate by the feed gear 19.
While being guided in the boss portion 32 of the impeller 16 by the screw 18 of 17, the sheet is conveyed toward the left side in FIG. 2, that is, toward the inner side of the copying machine main body 2. The developer sent to the back side is impeller 16
The toner is discharged to the developer chamber 4 through the opening at the rear end and the exit hole 33 formed in the vicinity thereof. In this way, the developer taken out from the front side region (the right end region in FIG. 2) of the developer chamber 4 by the delivery screw shaft 24 is transferred to the back side region of the developer chamber 4 by the delivery screw shaft 17 ( It is conveyed to the left end region of FIG. 2) and mixed with the developer in the developer chamber 4. For this reason, the toner and the carrier in the developer are effectively stirred, and it is possible to prevent the deterioration of the image quality of the visible image due to insufficient stirring. It is also convenient to rotate the feed screw shaft 17 at a higher speed than the feed screw shaft 24 to prevent the developer from clogging the discharge pipe 27, the supply pipe 20, and the boss portion 32 of the impeller 16.

By the way, in a two-component developer, when it is used for a long period of time, the carrier in the developer deteriorates. Therefore, when the carrier deteriorates, it is necessary to replace the developer entirely.
The illustrated example is configured as follows so that this replacement work can be easily performed.

That is, as shown in FIG. 2, FIG. 5, FIG. 5a, and FIG. 6, the first cylindrical portion 35 of the connecting member 34 is fitted and fixed to the discharge pipe 27,
A movable cylinder 37 of a switching member 36 constituting a flow path switching means is rotatably fitted in the supply pipe 20 in the direction of arrow F, and the second cylindrical portion 38 of the connecting member 34 is provided outside the movable cylinder 37. It is fixedly fitted to the supply pipe 20. Both cylindrical parts 35, 38 of the connecting member 34
Further, the above-mentioned connecting pipe 31 is integrally fixed. Movable tube 37
A discharge pipe 39 protruding in the radial direction is integrally attached to the cylinder, and a notch 40 is formed in the cylindrical portion 38 so that the discharge pipe 39 does not interfere with the second cylindrical portion 38 when the movable cylinder 37 rotates in the direction of arrow F.
Are formed.

The discharge pipe 27 and the supply pipe 20 communicate with each other through a hole 41 formed in the discharge pipe 27, a connecting pipe 31, a hole 42 of the movable cylinder 37, and a hole 43 formed in the supply pipe 20 as shown in FIG. Through these, the developer in the discharge pipe 27 is guided to the supply pipe 20 as described above (arrow E). During a normal developing operation, the discharge pipe 39 occupies the position shown by the solid line in FIG. 6, and at this time, the discharge pipe 39 is blocked by the pipe wall of the discharge pipe 27. Therefore, the developer carried out from the developer chamber 4 to the outside of the developing device 3 by the discharge pipe 27 of the developer carrying means is introduced into the supply pipe 20, and then the whole amount of the developer passes through the supply pipe 20 of the developer carrying means. Returned to chamber 4.

When replacing the developer, the movable unit 37 and the discharge pipe are kept with the developing unit 1 set in a predetermined position in the copying machine main body 2.
Rotate 39 to the position shown by the chain line in FIG. At this time, the hole 43a formed in the supply pipe 20 and the discharge pipe 39 are aligned with each other. Therefore, if the developer is sent from the discharge pipe 27 to the supply pipe 20 in this state as described above, the developer is shown by the chain line in FIG. The entire amount flows out through the discharge pipe 39 as shown by the arrow. The operator receives the developer flowing out from the outlet of the discharge pipe 39 in a container (not shown). In this way, the developer in the developer chamber 4 can be discharged. The supply of new developer can be performed by using the toner supply device described later, and the developer can be easily replaced. After discharging the developer, the flow path switching member 36 may be returned to the position shown by the solid line in FIG. Thus, while the developing unit 1 is set in the copying machine main body 2, the old developer can be easily extracted by rotating the flow path switching member 36, and the developing unit can be removed from the copying machine main body as in the conventional case. It is not necessary to remove it and invert it to replace the developer.

In the above-described embodiment, the developer carry-out means and the developer carry-in means for circulating and mixing the developer are utilized, these are communicated with each other outside the developer chamber, and the developer carried outside the developer chamber is developed. Since the flow path switching means switches between returning to the developer chamber by the developer carry-in means and discharging the developer as it is, the structure for stirring the developer and the structure for discharging the developer are common. Although it is particularly advantageous because it can be realized, it is also possible to provide a discharge port at a portion of the developer carrying-out means outside the developing device and use this means exclusively for discharging the developer. Further, the illustrated developer carrying-out or carrying-in means and the flow path cutting means are merely examples, and a suitable structure known per se for carrying powder and switching the carrying path may be adopted. It is natural.

On the other hand, since the toner in the developer moves to the photoconductor drum 11 along with the developing operation and the toner is sequentially consumed, it is necessary to replenish the developer chamber 4 with the toner. In the embodiment, the developing unit 1 has a toner replenishing device.
44 are attached as follows.

That is, as shown in FIGS. 2, 4, and 5, a support plate 46 is fixed to the front end wall 7 of the developing unit 1 via a suitable number of support studs 45, and the above-mentioned supply pipe is provided. 20 extends through the support plate 46. The front end region of the supply pipe 20 is inserted into a hole 48 of a substantially cylindrical holding member 47 that constitutes one element of the toner supply device 44, and the portion of the hole 48 facing the inside of the holding member is opened. The opening 49 and the notch opening 50 formed in the supply pipe 20 coincide with each other. Therefore, the feeding screw shaft 17 located inside the supply pipe 20 is exposed inside the holding member 47 through these openings 49 and 50.

Inside the holding member 47, a toner tank 51 containing toner, in this case black toner, is detachably fitted from the right side of FIG. The position of the toner tank 51 is also schematically shown by a chain line in FIG. Inside the toner tank 51, there is provided a rotating body 53 for sending out toner, which is fixed to a rotating shaft 52. The rotating shaft 52 is rotatably supported by both end walls of the toner tank 51, and one end portion of the rotating shaft 52 is rotatably supported. A gear 54 located outside the tank 51 is fixed to the. The gear 54 is a drive gear 56 supported by the copying machine main body 2 via an intermediate gear 55 rotatably supported by a supporting plate 46 in a state where the developing unit 1 is mounted on the copying machine main body 2.
This drive gear 56 is drivingly connected to a toner replenishing motor (not shown) via an intermediate transmission gear, and the rotating body 53 rotates inside the toner tank 51 by the operation of this motor. At the time of this rotation, the tip of the rotating body 53 is brought into sliding contact with the inner peripheral surface of the cylindrical toner tank 51.

As is apparent from FIGS. 2 and 5, the cylindrical wall of the toner tank 51 is provided with a nozzle discharge port including a large number of small holes 57 facing the above-mentioned openings 49 and 50. Small hole 57 in the example shown
Although they are arranged in one line, they may be arranged in a plurality of lines or may be arranged in a staggered manner, and the arrangement state thereof can be appropriately selected.

When a toner replenishment signal for supplying toner to the developer chamber 4 is generated, the above-mentioned toner replenishment motor operates to set the developing unit 1 set at a predetermined position in the copying machine main body.
The rotating body 53 of the toner replenishing device 44 attached to the roller starts rotating. As a result, the rotating body 53 rotates around the axis of the rotating shaft 52 while sliding its tip end against the inner peripheral surface of the toner tank, and the toner in the tank 51 is sent out through a large number of small holes 57 and pushed out toward the screw shaft 17. . The sent-out toner is sent inside the boss portion 32 of the impeller 16 by the rotation of the sending-in screw shaft 17, and is replenished to the developer chamber 4 from the opening or the outlet hole 33 on the inner side thereof, and the other developer existing there. Mixed with. As described above, in this embodiment, the toner is replenished by utilizing the developer carry-in means that circulates the developer in the developing device, so that it is not necessary to provide each carry-in means, and the structure can be simplified.

If the toner in the toner tank 51 becomes empty, this tank 51
Is removed from the holding member 47, and a new toner tank containing toner is attached to the holding member 47. At that time, as shown in FIG. 5, a seal 58 is attached to the new toner tank 51 from above the small hole 57 and the small hole 57 is closed. Attach 51 to holding member 47.

Although it has been known in the past to send the toner in the toner tank from the tank by means of the toner sending rotating member, conventionally, the toner tank is provided with a discharge port consisting of a slender and relatively large opening, and the toner is sent from this opening. It was configured to. However, when the toner is sent out from such a large opening, a large amount of toner is sent out by one rotation of the toner sending-out rotating body in the tank, and the pressure per unit cross-sectional area of the sent-out toner becomes small, so that the toner is opened. There is a risk that the toner will adhere to the periphery and stain the toner tank. However, as shown in the configuration, when the toner is sent out from the large number of small holes 57, the pressure increases, and the toner has small holes as if the liquid were ejected.
It is possible to suppress the inconvenience that the periphery of the small hole 57 and the periphery of the openings 49, 50 of the toner tank 51, which are caused to flow out from the feeding screw shaft 24 to the feeding screw shaft 24, are soiled with the toner. Therefore, when the toner tank 51 is detached from the holding member 47, it is possible to reduce the inconvenience that the worker soils his hands and clothes. Further, by selecting the size and the number of the small holes, the amount of toner sent out from the toner tank by one rotation of the rotating body 53 can be regulated. Conventionally, no particular consideration was given to the delivery amount, so a means for regulating the amount of toner delivered from the toner tank was provided, but in this example, such special means can be omitted, and the configuration is simplified. Can be achieved.

Further, as shown in FIGS. 7 and 8, the cylindrical holding member 47
An elastic roller 59 made of sponge or foam parallel to the feeding screw shaft 17 is rotatably arranged in the space adjacent to the hole 48 of the toner tank 51, and the small hole 57 of the toner tank 51 is adjacent to the elastic roller 59. And the roller 59 is pressed against the outer peripheral surface of the toner tank 51, and the elastic roller 59
Gear 60 fixed to the spindle of the gear 54 of the rotating body 53 (Fig. 5)
May be engaged with. In this configuration, the elastic roller 59 rotates together with the rotating body 53 during toner replenishment, and the toner ejected from the small holes 57 is sprayed on the week surface of the elastic roller 59,
The toner that has rebounded on the roller surface is fed into the screw shaft.
Sent to 17. A scraper (not shown) for scraping off the toner attached to the elastic roller 59 is in contact with the elastic roller 59. If the elastic roller 59 that is rotationally driven in this manner is provided in pressure contact with the peripheral surface of the toner tank 51, the sealing property between the roller 59 and the peripheral surface of the tank is maintained, and the toner is scattered to the outside of the holding member 47. It is possible to prevent the toner from adhering to the peripheral surface of the toner tank 51 by the elastic roller 59 and keep the tank clean.

Drive gear provided on the body side of the copying machine for driving the rotating body 53
56 (FIG. 4) is rotatably supported by a lever 56a which is swingably supported by a side plate 83 of the main body via a pivot pin 56c, and this lever 56a is a replenishing solenoid 56b (or other driving means). ) Is rotated. That is, when the solenoid 56b is urged by the toner replenishment signal, the upper end of the lever 56a is pulled by the solenoid 56b, and the drive gear supported by the lever 56a engages with the intermediate gear 55 (FIG. 5). When the solenoid 56b is deenergized, the lever 56a is rotated clockwise by the action of a spring (not shown) to drive the drive gear.
56 is separated from the intermediate gear 55. As described above, only when the toner replenishment signal is generated, the solenoid is energized, the drive gear 56 engages with the intermediate gear 55, the rotating body 53 is rotated, and the toner is replenished. After the rotating body 53 is rotated for a predetermined time to replenish the toner, when the toner replenishment is stopped, the drive gear 56 is separated from the intermediate gear 55 and the rotation of the rotating body 53 is stopped. As is known per se, the toner replenishment signal may be generated by a toner concentration detecting means (not shown) when the toner concentration has dropped to a predetermined value, or the toner consumption amount and the developing amount may be reduced. roller
Utilizing the fact that the number of rotations of 10 is substantially proportional, the next toner replenishment signal may be generated when the developing roller 10 rotates a predetermined number of times after toner replenishment.

Also in the developer chambers 4R and 4B of the developing units 3R and 3B shown in FIGS. 2 and 3,
Toner replenishing devices 44R and 44B, which are exactly the same as the toner replenishing device for the first developing device 3, belong to these second and third toner replenishing devices.
Toner is supplied from each of the toner tanks 51R and 51B to the developer chambers 4R and 4B.

As described above, when the developing device is used for a long time, the developer in the developer chamber is discharged to the outside to replace the developer, but after removing the developer from the developer chamber as described above. ,
A developer tank (having the same form as the toner tank 51) containing a developer containing a carrier and toner can be set on the above-mentioned holding member 47, and the developer can be supplied to the developer chamber 4.

Next, the configuration relating to the support of the developing unit 1 will be described.

As shown in FIGS. 1 and 4, the slider 62 is pulled out to the front side (direction of arrow G in FIG. 4) of the copying machine main body 2 by a slide guide device 61 known per se, or conversely, to the back side (direction G). Similarly, the direction of arrow H) is slidably supported by the copying machine main body 2 so as to be pushed in.
A developing unit storage table 63 is supported by the. In the present example, the slider 62 and the storage table 63 constitute a carrier for a unit that slidably supports the developing unit 1 on the copying machine main body 2.

As shown in FIG. 9, the slider 62 is a support plate 6 on the front side.
4, a support plate 65 on the back side, and a substrate 66 connecting these, and both support plates 64, 65 have first to third connecting rods 67, 68, which extend parallel to each other in the sliding direction of the slider 62. Each end of 69 is fixed, and both support plates 64, 65 are reinforced by these connecting rods 67, 68, 69.

The storage base 63 also has a front support arm 70 and a rear support arm 71.
(Fig. 9), and these arms 70 and 71 have a lower cover 72.
Is stuck. Both support arms 70 and 71 and the lower cover 72 are pivotally supported by a third connecting rod 69 of a slider 62 so as to be rotatable in the direction of arrow I. Further, a pivot pin 73 (see FIG. 1) is attached to a storage base 63.
An upper cover 75 is rotatably supported in the direction of arrow J through the upper cover 75, and the upper cover 75 is normally held at the closed position shown in FIGS. 1 and 9 (the position shown by the chain line in FIG. 4). Has been done.

On the other hand, the outer peripheral surface of the front end wall 7 of the developing unit is formed in a cylindrical shape, and the outer peripheral surface of the rear end wall 8 is also cylindrical. Upper part 70 of both support arms 70 and 71 of storage 63
The a and 71a are formed in an arc shape that fits the outer peripheral surfaces of the end walls 7 and 8. In addition, an appropriate number of support arms 70 on the front side,
In the example shown in the figure, a support piece composed of two support rollers 76 and 77 is rotatably supported, and the front end wall 7 of the developing unit 1 is supported.
The outer peripheral surface of is supported by these support rollers 76 and 77 at two places. Further, in the illustrated example, when the developing unit 1 is pulled out from the copying machine main body 2 by the slider 62, the cylindrical end wall 8 on the back side of the developing unit 1 is the support arm 71 on the back side as shown in FIG. It is rotatably supported by the arcuate upper portion 71a. With these configurations, the developing unit 1 can rotate around its central axis O while being supported by the storage table 63.

The developing unit 1 supported by the storage table 63 is pulled out from the copying machine main body 1 by pulling out or pushing in the slider 62 in the direction of the arrow G as described above, and the others are the copying machine main body 1
Is set to a predetermined position inside. That is, the developing unit 1
When setting the, the slider 62 is moved to the arrow H (fourth position) while the developing unit 1 is carried on the storage table 63 as shown in FIG.
All you have to do is push it in the direction shown. Immediately before the completion of this pushing operation, a positioning pin 78 is provided on the rear end wall 8 of the developing unit 1 and projecting on the central axis O of the unit 1.
As shown in FIG. 3, a positioning hole 80 formed in the side plate 79 on the back side of the copying machine main body 2 or a bearing 81 fitted in the positioning hole 80.
, So that the rear side of the developing unit 1 is positioned with respect to the copying machine main body 2 and, thus, the photosensitive drum 11 supported at a predetermined position of the main body 2. At this time, as can be seen from FIG. 1, the end wall 8 on the far side is the support arm 71 of the storage stand 63.
Rises slightly from. Therefore, the rear side of the developing unit 1 is rotatably supported by the copying machine main body 2 via the positioning pin 78 and positioned with respect to the photoconductor drum 11.
On the other hand, the end wall 7 on the front side is 2 even after the developing unit 1 is set.
Although it is rotatably supported by two support rollers 76 and 77, a pin 82 (FIG. 4) protruding from the support arm 70 on the front side of the storage base 63 is attached to the front side plate 83 of the copying machine main body 2. The drilled positioning hole or the receiving member 85 fitted in the positioning hole.
Fits into the center hole of the photoconductor drum 11
Positioned with respect to. Therefore, the front side end wall 7 of the developing unit 1 supported on the front side of the storage base is
The developing unit 1 is positioned on the front side and the back side (that is, the entire unit) at a predetermined position parallel to the photosensitive drum 11 via the. In addition, the back side of the storage base 63 also has its support arm 71.
A pin 86 (see FIG. 9) projecting from the front side is fitted into a hole (not shown) formed in the side plate 79 on the rear side of the main body so that the rear side of the storage stand 63 is fixedly positioned and supported by the main body 2 of the copying machine. It

In the example illustrated above, the developing unit 1 set in the main body of the copying machine has a storage base whose back side is positioned in the main body 2 of the copying machine and whose front side is positioned in the main body 2 of the copying machine.
Positioned on the body 2 via 63. As a result, the entire developing unit 1 is positioned with respect to the photosensitive drum 11, but when the storage table 63 is inserted and set in the main body of the copying machine, the entire storage table 63 is set by the pins 82 and 86 described above. The supporting arm 71 on the back side of the storage table 63, which is positioned with respect to the copying machine body 2, is provided with a supporting roller similar to the rollers 76 and 77 on the front side. The end wall 8 is rotatably supported by the support roller of the back side support arm 71, and the entire developing unit 1 (back side and front side) is passed through the storage base 63, and thus the copying machine main body 2, and thus the photosensitive drum 11. Can also be positioned relative to.

Further, in this example, as will be described later, a movable support roller 87 is movably supported in the vertical direction on a front side plate 83 of the copying machine main body 2.
By (FIG. 4), the upper part of the front end wall 7 of the developing unit 1 set in the main body 2 is pressed. Therefore, the end wall 7 of the developing unit 1 set at a predetermined position in the main body of the copying machine has three support rollers 76, 77,
Supporting from three sides by 87, the developing unit 1 can rotate about its central axis O while keeping its position correctly.

A circumferential groove (not shown) is formed on the front side end wall 7, rollers 76 and 77 are fitted therein, and a rear side end wall 8 is also provided with a circumferential groove. The unit 1 can be positioned in the front-back direction by allowing 71 or rollers to be fitted.

The developing operation of the first developing device 3 is as described above. However, when a visible image is formed by the red or blue developer contained in the second or third developing device 3R, 3B, a copying machine is used. By rotating the developing unit 1 set at a predetermined position in the main body in the clockwise direction in FIG. 1, the second or third developing unit 3R, 3B is driven.
The developing roller 10R or 10B of the first developing device 3 shown in FIG.
The developing roller 10 is brought to the developing position where the developing roller 10 is located, and the developing operation is performed. Each developer contains the same color developer, or cyan, magenta, and yellow toners respectively, and the electrostatic latent image on the photoconductor drum is sequentially visualized with these toners to obtain a full-color visible image. The same applies when the developing device is configured so as to form.

As described above, each of the developing devices 3, 3R, 3B occupies a predetermined developing position, and a developing operation for visualizing the electrostatic latent image formed on the latent image carrier composed of the photosensitive drum 11 can be performed. As described above, the developing unit 1 is rotatably supported so as to face the photosensitive drum 11.

For the purpose of rotating the developing unit 1 set in the main body of the copying machine as described above, as shown in FIG. 9 and schematically shown in FIG. Supported by a gear 89 which is a unit gear 90 formed on the peripheral surface of the rear end wall 8 of the developing unit 1.
Meshes with. When the operator selects and depresses a color conversion key switch (not shown) with the developing unit 1 pushed into the copying machine main body 2 and set, the drive motor
When the 88 operates, the clutch interposed between the motor 88 and the gear 89 is turned on, and the developing unit 1 and the toner replenishing devices 41, 44R, 44B assembled to the developing unit 1 and the central axis O thereof.
Rotate around. As a result, the developing device selected, for example, the developing roller 10 of the developing device 3 of the stand 1 reaches the developing position,
At this time, the motor 88 stops operating, or the clutch is turned off, the developing unit 1 stops, and the developing operation described above is performed. In this case, as can be seen from FIGS. 1, 4, and 9, the developing units 3, 3R, 3B and the toner replenishing devices 44, 44R, 44B of the developing unit 1 are centered on the axis O of the developing unit 1. As the toner replenishing devices 44, 44R, 4 are evenly arranged in a radial pattern
The center of gravity of 4B lies on the rotation axis O of the developing unit 1. As a result, these rotating operations are smoothly performed with a small amount of power. By making the structures of the respective developing devices 3, 3R, 3B and the respective toner replenishing devices 44, 44R, 44B identical to each other, their constituent parts can be made common,
The manufacturing cost can be reduced.

Here, since the toner replenishing devices 44, 44R, 44B are provided in the space on the labor side of the developing unit 1, the entire developing device is compact as compared with the case where the toner supplying device is provided on the outer side in the radial direction of each developing device. Can be converted. Moreover, the developing unit 1
Toner supply device 44,44R, 44B in a large space in front of
Since the above is provided, the amount of toner to be replenished, that is, the capacity of the toner tank can be increased.

However, when the toner supply devices 44, 44R and 44B are arranged in front of the unit 1 in this way, the supply pipe for conveying the toner and the support stud 45 project from the end wall 7 of the developing unit 1. On the other hand, for the purpose of enabling the developing unit 1 to rotate about its axis O, a supporting shaft is provided so as to project at the center of the end wall 7 of the developing unit and is supported by a bearing as described above. I supported the development unit rotatably,
As described above, when the toner supply pipe 20 and the like project from the end wall 7, there is no space for arranging a bearing for supporting the shaft even if the shaft is projected on the end wall 7, so that the shaft and the bearing do not interfere with each other. It is impossible to adopt the conventional configuration. If a support stud is attached to the center of the end wall 7 as in the example shown in the figure, a spindle cannot be provided. Therefore, in this example, as described above,
The outer peripheral surface of the end wall 7 is formed into a cylindrical shape, and this peripheral surface is supported by a supporting piece composed of three supporting rollers 76, 77, 87. Therefore, the developing unit 1 can be rotatably supported without any trouble even if the supply pipe 20 or the like exists outside the front side of the end wall 7. Instead of the support rollers 76, 77, 87, the end wall 7 may be rotatably supported by a support piece made of, for example, a pin. The number of parts that support the end wall 7 by the support piece is not limited to three, and may be two or more. Further, in the example of the drawing, the back side of the developing unit 1 set in the copying machine main body 2 is located on the back side if the positioning pin 78 is fitted into the positioning hole 80 to rotatably support the unit 1. As described above, it may be rotatably supported by at least two support pieces. When the developing unit is not configured to be pulled out, the supporting piece may be provided in the copying machine main body. In this way, the outer peripheral surface of at least one of the two end walls that partition the ends of the developer chambers of the plurality of developing devices in the developing unit is formed into a cylindrical shape, and at least two of the outer peripheral surfaces are formed. It suffices to support rotatably by the support piece. Since the end wall that defines the developer chamber of the developing unit 1 is a cylindrical supported surface and is supported by the supporting piece, it is not necessary to provide a special supported member in the developing unit, and the increase in cost is suppressed. can do. Further, the outer shapes of the end walls 7 and 8 are relatively large, but if the end walls are supported by bearings that are in contact with the entire circumference of the end walls, the entire structure becomes large. The structure can be made compact if the wall is supported by a plurality of support pieces.

Next, the configuration related to the developer scattering prevention of the illustrated developing device will be clarified.

When the above-described developing operation is performed or when the developing unit 1 is rotated, it is unavoidable that some developer spills from the opening of the casing member 5 where the developing rollers 10, 10R and 10B are located. However, if this is left unattended, the developer will be scattered and this will cause various elements inside the main body of the copying machine.
In particular, it may adhere to the optical element and deteriorate the function of the copying machine.

Therefore, in the illustrated example, the storage table 63 is provided with the above-mentioned upper cover 75 and lower cover 72, and as shown in FIG. 1, the developing unit 1 is covered from above and below by these covers 72, 75, whereby the developer is It is prevented from scattering upward or downward. The developing roller 10 located at the developing position is exposed toward the photoconductor drum 11 through the gap between the free ends of the upper and lower covers 75 and 72.

Since the upper cover 75 is rotatably supported on the storage table 63 as described above, if the slider 62 is pulled out from the copying machine main body 2, the upper cover 75 can be opened as shown by the solid line in FIG. The developing unit 1 can be rotated without any trouble as described later, or can be removed from the storage table 63. At this time, since the supporting roller 87 is supported by the copying machine main body 2 and is not in contact with the pulled-out developing unit 1, the developing unit can be removed from the storage table 63 without being disturbed by the roller 87. You can When pushing the slier 62 into the copying machine main body 2 again, the upper cover 75 is returned to the position shown by the chain line in FIG.

Further, the lower cover 72 has a receiving portion 91 (FIGS. 1, 4, and 9) for receiving the developer spilled from the developing unit 1.
(Figure) is formed, and the spilled developer can be stored therein. The operator sometimes pulls out the slider 62,
The developing unit 1 may be removed from the storage table 63 and the developer accumulated in the receiving portion 91 may be cleaned.

As shown in FIG. 10, a removable tray-shaped developer receiver 92 is provided on the lower cover 72, and if the developer is stored therein, the receiver 92 can be easily removed from the lower cover 72. Cleaning work can be performed.

When a magnetic developer is used as in this example, if the upper and lower covers 75 and 72 are made of a magnetic material, the developer on the developing roller is attracted to these covers by magnetic force, and the developer is removed from each developer chamber. The upper and lower covers 72, 72 are made of a non-magnetic material because they may easily come out. Also the lower cover 7
2 or when the magnetic developer falls on the receiver 92, if this developer is attracted to the side of each developing roller 10, 10R, 10B by the magnetic force, there is a possibility that developers of various colors are mixed in each developer chamber. Therefore, the receiving portion 91 of the lower cover 72 or the developer storing portion of the receiving portion 92 is provided in a range where the magnetic forces of the magnets 21, 21R, 21B passing therethrough do not reach. The receiving part shown in FIG.
91 and the receiver 92 of FIG. 10 are recessed in the lower part of the figure.
This is the reason.

In FIG. 1, the casing member portion 150 on the downstream side of the doctor blade 22 is brought close to the developing roller 10, and the portion 150 and the developing roller 10 form a relatively narrow region, which is conveyed in this region. This is to prevent the developer in the developer chamber from flowing out by being filled with the developer.

Further, during the developing operation, the developer is carried on the developing roller while being carried by the developing roller. To prevent the carried developer, especially the developer existing in the developing area D, from scattering in all directions, see FIG. As shown, the casing member 5 of the developing unit 1 is provided with a first seal member 93 made of, for example, an elastic film made of synthetic resin, a sheet (polyurethane rubber sheet, polyester film, etc.) or a flexible brush. The developing roller 10 attached to the
Is in the developing position, the tip of the first seal member 93 abuts on the surface of the photosensitive drum on the upstream side of the developing area D to prevent the developer from scattering above the seal member 93. .

By the way, when the developing unit 1 is rotated, the first seal member 93 makes sliding contact with the peripheral surface of the photosensitive drum 11. Therefore, if the seal member 93 is made of a hard material, the member 93 may damage the surface of the photosensitive drum. Therefore, the seal member 93 needs to be made of a soft material that does not scratch the drum surface. However, the seal member
If 93 is made of such a soft material, the pressure at which the seal member 93 contacts the photoconductor drum 11 during the normal developing operation is lowered, which inevitably causes the sealing function to be lowered.

Therefore, in the configuration shown in the figure, the second seal member 94 is supported at the tip of the upper cover 75, and the tip thereof is in contact with the peripheral surface of the photosensitive drum 11. That is, the periphery of the developing roller or the developing area D is sealed by the two sealing members 93 and 94.
Therefore, even if each of the seal members 93, 94 is soft and the sealing function thereof is slightly low, a reliable sealing effect can be obtained by the double seal. The second seal member 94 can also be composed of, for example, a synthetic resin elastic film, sheet, or flexible brush. Further, the second seal member 94 is provided at an appropriate place other than the upper cover 75, for example, the developing unit or the copying machine main body 2.
May be mounted on the side.

When one end of the first seal member 93 is supported by the developing unit 1 and one end side of the second seal member 94 is also supported by the developing unit as described above, these seal members are rotated when the developing unit 1 rotates. 93 and 94 are slidably contacted with the photosensitive drum 11 and deformed. At that time, if the developing unit 1 rotates around its center O in the counterclockwise direction in FIG. 1, for example, the first seal member 93 may be the photosensitive drum.
External force from 11 causes a large bending deformation as shown by the alternate long and short dash line, and in some cases the sealing members 93,94
May be damaged. Therefore, in this embodiment, the developing unit 1 is configured to rotate only in the clockwise direction in FIG. In this way, when the unit 1 rotates, the seal member 93 only needs to be slightly bent and deformed as shown by the broken line in FIG. 1 at the maximum, and a large external force is exerted on the seal members 93, 94 and the photoconductor drum 11. Can be removed. That is, the developing unit 1 is rotated to bring each developing device to the developing position only in the direction in which the bending deformation amount of the seal member decreases when the developing unit rotates.

The developing unit described above needs to be cleaned, inspected, or adjusted (e.g., position adjustment of the docker blades 22, 22R, 22B, etc.), or repaired for each element periodically or as necessary, or repaired. As described above, the slider 62 is pulled out to the front side, the developing unit 1 is brought out of the main body of the copying machine, and the upper cover 75 is lifted to the open position shown by the solid line in FIG. Therefore, even if the weight of the developing device is large, the worker can easily perform the work without soiling his hands and clothes with the developer. At that time, in particular, a developing unit 1 including a plurality of developing devices 3, 3R, 3B as in this example.
It is necessary to not only inspect and repair one surface of the developing unit 1 but also to inspect and repair the entire circumference thereof. Even when the slider 62 is pulled out as described above, the developing unit 1 has its end walls 7, Since 8 is rotatably supported by the two support rollers 76 and 77 of the storage base 63 and the upper portion 71a of the support arm 71 on the back side, the unit 1 can be freely rotated while being mounted on the storage base 63. You can Therefore, any part of the outer circumference can be easily oriented toward the operator, and the required work can be performed easily and efficiently.

Push the developing unit 1 into the main body 2 of the copying machine to set it,
For example, when the developing roller 10 of the stage 1 developing device 3 is positioned in a predetermined developing device, the developing roller 10 is moved to the photosensitive drum 11
They are placed opposite to each other with a minute gap. Further, when a one-component developer is used, the developing roller 10 may be brought into pressure contact with the photosensitive drum 11. For this reason, the developing unit 1
The storage base 63 is in contact with the photoconductor drum 11, or is located close to the photoconductor drum 11 as shown in the figure. Therefore, when the storage table 63 is pulled out or pushed in in this state, a part of the storage table 63 or the developing unit 1 interferes with the photoconductor drum 11, and the surface thereof is scratched or carried on the surface of the developing roller 10. The developed developer is scraped off by the photosensitive drum 11 and drops downward,
There is also a possibility that the periphery of the developing device or the copying machine may become dirty.

Therefore, in the illustrated developing device, when the developing unit 1 is attached to or detached from the copying machine main body 2, the developing unit 1 and the accommodating base 63 are released in a direction of separating from the photosensitive drum 11, and the developing unit 1 is set in the copying machine main body 2. When this is done, the unit 1 is configured to be positioned at a predetermined position close to the photosensitive drum 11. The specific configuration is as follows.

As shown in FIGS. 4 and 9 and as described above, the storage base 63 is rotatably supported by the third connecting rod 69 of the slider 62. At this time, an appropriate number of tension springs 95 are stretched between the storage table 63 and the slider 62 (see also FIG. 1), and the storage table 63 is separated from the photosensitive drum 11 with respect to the slider 62 about the connecting rod 69. It is biased in the direction I. When the storage table 63 is pulled out, the storage table 63 contacts the slider, and the storage table 63 is held at a position separated from the photosensitive drum 11 on the slider side as shown in FIGS. 4 and 9. .

When the slider 62 is pushed in the direction of the arrow H, the storage base 63 and the developing unit 1 are pulled in the direction away from the photoconductor drum 11 by the tension spring 95 as described above, so that they interfere with the photoconductor drum 11. There is nothing to do. Immediately before the slider 62 reaches the innermost set position, the positioning pin 78 (FIG. 3) of the developing unit 1 is fitted into the positioning hole 80 of the side plate 79 on the far side via the bearing 81 and is stored as described above. Stand 63
The pin 82 projecting from the front support arm 70 (see FIG. 4) of the above is fitted into the hole of the front side plate 83 through the receiving member 85, but at this time, the tips of both pins 78 and 82 are thin. Since it is formed as a taper pin, when the pins 78 and 82 are fitted together, the storage stand 63 resists the action of the spring 95 together with the developing unit 1 and approaches the side of the photoconductor drum 11 so as to approach the side of the photosensitive drum 11. Rotate around. That is, as shown by the chain line in Fig. 11, the pin
Before the 78 is fitted into the bearing 81, the central axis O of this pin 78
Is displaced from the axis X of the bearing 81 by a distance δ from the photosensitive drum 11. However, when the tip of the pin 78 starts to be fitted into the bearing 81, the axis O of the pin 78 is aligned with the axis X of the bearing 81 while the tapered portion of the tip is guided by the hole of the bearing 81.
When the pin 78 is completely fitted, the axes O and X coincide with each other. This relationship is exactly the same for the pin 82 and the receiving member 85. In this way, the storage table 63 and the developing unit 1
After the setting is completed, they approach the photosensitive drum 11 by δ, and the developing roller 10 is correctly positioned parallel to the photosensitive drum 11 with a minute gap.

In addition, in this example, after the setting is completed, the end wall 8 on the back side is stored in the storage base 63.
Pin 7 so that it lifts from the upper part 70a of the rear support arm.
The bearing 8 is also slightly lifted upward by the bearing 81.

On the contrary, when pulling out the storage base 63, as the pins 78 and 82 are disengaged from the bearing 81 and the receiving member 85, the storage base 63 is pulled by the tension spring 95 together with the developing unit 1 in the direction away from the photosensitive drum 11, and The storage table 63 and the developing unit 1 are pulled out without contacting the photosensitive drum 11.

By directly fitting the pins 78 and 82 into the holes 80 and 84, or by another guide member, the developing unit 1 and the storage base 63
As a matter of course, the means for moving the light source toward or away from the photosensitive drum 11 may be configured as described above.

When the developing unit 1 is set on the main body 2 of the copying machine, the front end wall 7 of the unit 1 is supported by the two supporting rollers 76 and 77 from below and is supported by the main body 2 of the copying machine from above. It is pressed by the movable supporting roller 87. The reason why the roller 87 is supported by the main body of the copying machine is to allow the developing unit 1 to be taken out freely without being disturbed by the roller 87 when the developing unit 1 is pulled out. The reason why the developing unit 1 is movable is that the storage unit 63 prevents the developing unit 1 and the like from interfering with the roller 87 when the developing unit 1 is pulled out or pushed in. A specific configuration example for the vertical movement is as follows.

In FIG. 12, the side plate 83 on the front side of the copying machine body 2 is
A rotating arm 100 is rotatably supported in a horizontal plane in the direction of arrow K via a bracket 99, and the arm 100 is biased toward the front side by a torsion coil spring 101 as shown by a solid line in FIG. There is. One end of a first link 102 is pivotally attached to the tip end region of the rotating arm 100, and one end of a second link 103 is pivotally attached to the other end of the link 102.
The other end of 03 is pivotally attached to a support member 104 that rotatably supports the movable support roller 87 via a pivot pin 105. The supporting member 104 is pivotally supported by a supporting bracket 106 fixed to a front side plate 83 of the copying machine body via a pin 107 so as to be rotatable in the arrow P direction. The pin 107 is located below the portion where the second link 103 is pivotally attached to the support member 104. A pressure roller 108 is supported on the lower part of the tip of the rotating arm 100.

When the storage table 63 and the developing unit 1 are pulled out,
By the action of the spring 101, the rotating arm 100 occupies the position shown by the solid line in FIG. 12, and at this time, the movable support roller 87 is also retracted to the position shown by the solid line outside the movement path of the storage table 63. Therefore, if it is pushed in together with the storage table 63 and the developing unit 1 in this state, they will not interfere with the movable support roller 87.
Immediately before the storage table 63 reaches the final position on the back side, the pressure member 109 (see also FIG. 4) attached to the slider 62 is
The pressured roller 108 is pushed inward. As a result, the pivot arm 100 pivots to the position shown by the chain line, and the support member 104 is pushed leftward in FIG. 12 via the two links 102 and 103, and the pin 1
Rotate around 07 counterclockwise. Therefore, the movable supporting roller 87 is lowered downward, and at this time, the end wall 7 on the front side is located below this roller 87, so that the roller 87 is a spring.
By the action of 101, it can be pressed against the peripheral surface of the end wall 7.

When the developing unit 1 is pulled out, the reverse operation is performed. Therefore, at this time also, the movable supporting roller 87 moves the developing unit 1
It does not interfere with the storage table 63.

At least one of support pieces consisting of a plurality of support rollers 76, 77, 87 (or pins) that support the end wall 7.
It is sufficient to support one end of the end wall 7 like the above-mentioned movable support roller that moves up and down, and it is not always necessary to support only one roller 87 so as to be movable.

Further, instead of supporting the supporting roller 87 for pressing the upper part of the end wall 7 on the main body of the copying machine so as to be movable up and down as shown in FIG. 12, as shown by a chain line in FIG. If the support roller 87a is rotatably supported by the upper cover 75, the mechanism for moving it up and down can be omitted. That is, the developing unit 1
The upper cover 75 is closed as shown in FIG. 1 so that the roller 87a does not interfere with the unit 1 and the like, and the developing unit 1 is pulled out. When this is taken out from the storage table 63, the upper cover 75 can be opened as shown by the solid line in FIG. 4, so that the support roller 78a does not interfere. In this way, by rotating the upper cover 75, the supporting roller 78a can be brought into contact with and separated from the developing unit.
It suffices to simply rotatably support the 78a on the upper cover 75. In this case, when the upper cover 75 is closed, the support roller 78
Advantageously, the upper cover 75 is biased towards the end wall 7 by a spring (not shown) so that a can be pressed against the end wall 7. Alternatively, the upper and lower covers 75 are made of an elastic material such as synthetic resin, and when the cover 75 is closed, it is stopped at a predetermined position as shown in FIG.
When the developing unit 1 is set in the copying machine main body 2, a pressing member attached to the main body presses the upper cover 75 downward, whereby the support roller 78a is pressed against the end wall 7. Good.

As described above, the developing roller 10, the feed screw shaft 24, and the feed screw shaft 17 brought to the developing position.
Are respectively driven via gears 14, 26, 19 fixed to them respectively. In this case, as shown in FIGS. 9 and 13, the developing roller gear 14 meshes with the sending gear 26 of the sending screw shaft 24, and this gear 26 meshes with the sending gear 19 of the sending screw shaft 17, so that the developing roller gear 14 is By driving the rotation, the other two gears 2
6,19 are driven to rotate. The same applies to the gears of other developing devices. At this time, if the developing roller gear of each developing device is driven by each driving source, the size of the apparatus is increased and the cost is increased, which is not preferable. Therefore, in this embodiment, as shown in FIGS. 3 and 13, the shaft 1 of the photosensitive drum 11 rotatably supported by both side plates 78 and 83 of the copying machine main body 2.
The drive gear 111 is rotatably supported by the motor 10 in a stationary manner, and the gear 14 of the developing roller 10 of the first developing device 3, for example, brought to the developing position meshes with the drive gear 111, and the motor is not shown. By driving these gears 111,14,2
The developing roller 10 and the screw shafts 24, 17 are rotationally driven via 6, 6. The centers of the developing roller gears 14, 14R, 14B are arranged around the rotation center O of the developing unit 1 at equal intervals and at the same distance from the center O. By rotating the developing unit 1 around its center O,
The developing roller gears 14R and 14B of the other developing devices 3R and 3B are selectively meshed with the drive gear 11. In this way, all the developing devices 3, 3R, 3B can be driven by one driving source. The drive gear 111 may be supported at an appropriate position other than the developing unit 1.

Similar to FIG. 1, FIG. 13 shows a state in which the developing roller of the first developing device 3 occupies the developing position, and its gear 14 meshes with the drive gear 111, but the other developing devices 3R, 3B To engage the developing roller gears 14A and 14B with the drive gear 111, the drive motor 88 rotates the gear 89 and the unit gear 90 of the drive unit 1 to rotate the developing unit 1 in the clockwise direction (arrow Q direction). , Developing roller gears 14, 14A, 14B,
It revolves around the central axis O and other developing roller gears
14R and 14B may be brought to the position of the developing roller gear 14 shown in FIG. 13 and engaged with the drive gear 11.

Here, as shown in FIG. 13, when the rotation center of the developing roller gear 14 located at the developing position is O ′ and the rotation center of the drive gear 111 is O ″, these centers O ′, O ″ and the developing unit 1
The rotation center (center axis line) O of is located on the same straight line l or substantially on this straight line l. As a result, the developing unit 1 rotates about its center O and the developing roller gears 14, 1
When 4R and 14B revolve around the center O of the developing unit,
These gears 14, 14R, 14B do not interfere with the drive gear 111. If, as shown in FIG. 17, three gears 111, 14, 9
∠OO ′ without arranging the centers O, O ′, O ″ of 0 on a straight line
Assuming that O ″ = β forms an angle smaller than 180 °, when the developing roller gears 14, 14R, 14B revolve around the center O in the direction of arrow Q, they interfere with the drive gear 111 and the revolution does not occur. Therefore, in this case, when the developing roller gear revolves, the drive gear 111 has to be retracted to the outside of the revolving path of the developing roller gears 14, 14R, 14B, and a mechanism therefor is required, which complicates the configuration. There is an inevitable drawback.

As shown in FIG. 18, the drive gear 111 can be arranged inside the gear 14 of the developing roller 10 located at the developing position, but in this case as well, the center O ′, O ″ of the two gears 14 and 111 and the developing unit. If the rotation center O of No. 1 is arranged on the straight line l or substantially on the straight line l, each developing roller can revolve around the center O without interfering with the drive gear 111.

By the way, when one of the developing roller gears 14, 14R or 14B starts to engage with the drive gear 111 as the developing unit 1 rotates, as shown in FIG.
B and the tooth tops of the drive gear 111 may collide with each other, and these gears may stop, or the teeth of the gear may be cut off. Therefore, in this embodiment, a certain developing roller gear 14, 14R is used.
Alternatively, by the time immediately before 14B starts to mesh with the drive gear 111, the drive gear 111 has been rotated clockwise (arrow R in FIG. 13).
Direction) has already begun to rotate. That is, when the developing roller gear revolves and any one of the gears engages with the driving gear 111, the gear 111 is already rotated. With this configuration, when the developing roller gear, for example, the gear 14 of the first developing device 3 starts to mesh with the drive gear 111, even if the tooth tips of both gears 14 and 111 abut against each other as shown in FIG. Drive gear 11
By the rotation of 1, both gears immediately release the abutment between the tooth tips and are brought into a predetermined correct meshing state. This can prevent the above-mentioned inconvenience. The drive gear 111 may start rotating until just before any of the developing roller gears starts to engage with the gear 111. Therefore, by pressing the color conversion key switch, the developing unit 1 starts to rotate at the same time. The drive gear 111 may be started to rotate, or the drive gear 111 may be continuously rotated when the power of the copying machine is in the on state.

Further, as described above, the direction R in which the drive gear 111 is rotated before the developing roller gear is engaged is the clockwise direction in FIG. 13, and the direction in which the developing roller gear revolves around the center O is also indicated by the arrow Q. As you can see, it is clockwise. That is, when the developing roller gear and the driving gear 111 are engaged with each other, the moving directions of the two in the engaging area are opposite to each other, and the relative speed at the engaging portion of the both becomes large. The rotation direction of is set. Therefore, the abutment of the tooth tips of both gears is released more accurately and promptly, the both gears are immediately brought into the proper meshing state, and it is possible to more effectively eliminate the above-mentioned trouble.

When the respective gears are arranged as shown in FIG. 18 and the developing roller is rotated in the counterclockwise direction during the developing operation, the drive gear 111 rotates in the counterclockwise direction. When meshing with the drive gear 111, the gear 111 is rotated counterclockwise. Therefore, in this case, in order to increase the relative speed of the revolving developing roller gear and the drive gear 111, the rotation direction of the developing unit 1 may be set counterclockwise. As described above, in any case, the rotation direction of the developing unit may be determined so that the relative speed in the engagement region between the revolving developing roller gear and the drive gear 111 becomes large.

The developing roller gear to be engaged with the driving gear 111, not the driving gear 111, is rotated around its rotation center O by a proper driving means other than the driving gear at a suitable time until just before they are engaged with each other. It may be configured to be driven (rotated), or both the developing roller gear and the drive gear 111 may be configured to be rotationally driven around their respective rotation centers O ′ and O ″.

Next, a more specific example of the above-described configuration and each developing roller 10, 10R, 10B of the developing unit 1 is positioned at a predetermined position, and the developing roller of any one of the developing devices 3, 3A or 3B is at the developing position. An example of a specific configuration for detecting whether or not it has been brought to is described.

In FIG. 13, the developing unit 1 is located upstream of the developing area D with respect to the rotating direction of the developing unit 1 (direction of arrow Q), and in the circumferential direction around the developing unit 1, for example, a developing roller is provided. The same number of sensors P1, P2, P3 are arranged side by side and fixedly arranged in the copying machine main body 2.

On the other hand, the developing unit 1 is integrally provided with light-shielding plates F1, F2, F3 having different circumferential lengths and arranged at equal intervals in the circumferential direction.

The developing unit rotates in the direction of arrow Q, and the rotation center O of the developing unit, the rotation center O ′ of the developing roller 10, the rotation center of the photosensitive drum 11, that is, the rotation center O ″ of the drive gear 111.
When and coincide with the line l, the light shielding plate F2 turns off the sensors P2 and P3 of the sensors P1 to P3.

Here, for example, a well-known photocoupler is used as each of the sensors P1 to P3, and the one seen from the arrow Y direction in FIG. 13 is shown in FIG. In this figure, the light from the light emitting element 112 is blocked by the light shielding plate F2, so that the light receiving element 113 is turned off. That is, in the case of FIG. 13, the sensors of only P3 and P2 are turned off.

When the developing roller gear 14R meshes with the drive gear 111 and the developing roller 10R is placed at the developing position, the light shielding plate F1 is operated by the sensor P.
Turn off only 3.

When the developing roller gear 14B meshes with the drive gear 111 and is placed at the developing position of the developing roller B, the light shielding plate F3 turns off all the sensors.

The above relationships are summarized in the table below.

As can be understood from Table 1, since the combination of ON / OFF is different for each developing roller, it is possible to determine which developing roller is at the developing position. That is, each developing roller 10, 10 of the developing device designated by the color conversion key switch
It can be detected that R and 10B have reached a predetermined developing position.

Light-shielding plates F1, F2, F3, etc. rotate integrally with the developing unit to turn each sensor on and off, and the combination of this on and off changes each time each developing roller is placed in the developing position. It constitutes an example of the receiving material. Note that depending on the configuration of the detected member and the type of sensor, the ON / OFF of Table 1 shown above can be reversed. For example, as shown in Table 2 below.

By the way, in Table 1 shown above, the sensor P3 is off in any of the developing rollers.
That is, the sensor P3 is always turned off regardless of which developing roller is placed at the developing position. On the other hand, in the case of Table 2, it is always turned on.

When the sensor P3 is turned off (in the case of Table 1) or turned on (in the case of Table 2), it is possible to detect that the unspecified developing roller is placed at the developing position.

FIG. 15 is a diagram for explaining a process until the developing roller gear 14 meshes with the drive gear 111, and a line L is a revolution locus around O of the rotation center O ′ of each developing roller gear 14.

By turning on the color conversion key switch described above, the developing unit 1
When the rotation center O'of the developing roller gear 14 reaches the point S in the figure, the gear positions are such that the addendum circles of the gear 14 and the drive gear 111 are in contact with each other. After that, the gear 14 normally comes on the line l and the teeth are normally meshed with each other, but in some cases, the tooth tips may be left in contact with each other, as described above.

Here, in FIG. 15, the angle formed by O′O and SO is θ
And In this case, if the angle A formed by the line connecting the most downstream sensors P3 and O with respect to the unit rotation direction and the line connecting the most upstream sensors P1 and O is equal to the angle θ (∠O′OS),
When the gear 14 reaches the point S, the shading plate F2 (Fig. 13) reaches the sensor P1, and when the gear 14 reaches the developing position, the shading plate F2 reaches the sensor P3. In this embodiment, the most upstream sensor P1 is installed at a position where the angle A is slightly larger than the angle θ (∠O′OS) (θ + α). Immediately before one of the developing roller gears meshes with the drive gear 111, one of the light-shielding elements F1 to F3 turns on or off the sensor P1, and the drive gear 111 is rotated by this signal to cause the developing roller of the selected developing device to rotate. When it reaches the developing position, it is detected by the sensors P1 to P3 as described above, and the drive motor 88 or the clutch thereof is turned off as described above by the developing device positioning signal. FIG. 20 is a flow chart showing a series of these operations. Drive gear 11 like this
By setting the rotation start timing of 1 immediately before the development roller gear engages with this, the gear 111 and the development roller gear can be skillfully meshed with each other.

Further, as shown in FIG. 9 and FIG. 16, the rear end wall 8 of the developing unit 1 is provided with a positioning groove-like positioning cam for each developing device.
114, 114R, 114B are formed. On the other hand, a lever 116 urged toward the end wall 8 by a tension spring 115 is pivotally supported on the back side support arm 71 of the storage table 63, and this lever 116 is
A stopper composed of a stop roller 117 is rotatably supported, and the roller 117 selectively engages the three cams 114, 114R, 114B to exert a braking force on the developing unit 1. , The developing rollers 10, 10R, 10 are positioned at the developing position. Further, when the developing operation is performed, for example, the developing roller 10 of the developing device 3 in the developing position rotates counterclockwise in FIG. 1 or 13, but the load is large (load due to circulation of the developer). . Therefore, this rotation causes the developing unit 1 to have its center O
A counterclockwise moment in Fig. 13 acts around the. However, at this time, the stop roller 117 causes the cam 1
Since it is engaged with 14, the moment is canceled,
This moment prevents the disadvantage that the developing unit 1 rotates due to this moment. Further, in this example, the developing unit 1 is configured to rotate in the clockwise direction Q which is opposite to the direction of the moment applied by the developing roller 10 (counterclockwise direction in FIG. 13). Since the rotation of the developing unit 1 is blocked by the drive motor 88 or its transmission device, it is possible to prevent the developing unit 1 from rotating counterclockwise due to the above-mentioned moment.

Incidentally, 116a in FIG. 16 is a stopper for the roller 117. Further, if at least one of the surface of the roller 117 and the surfaces of the cams 114, 114R, 114B is made of an elastic body, it is possible to reduce the shock when the roller 117 is engaged with or disengaged from the cam. It is advantageous. However, the elasticity is such that the positioning effect is not impaired by the roller 117.

As described above, according to the above-mentioned configuration related to FIGS. 13 to 16, the developing unit can be positioned and the developing roller cannot operate due to the abutment of the tooth tips of the developing roller gear and the driving gear with the simple configuration. Can be removed.

Further, as shown in FIG. 21, the tooth shapes of the developing roller gears 14, 14R, 14B and the drive gear 111 may be slightly changed from those of a normal tooth shape, and the tooth tips of both gears may be in line contact with each other. , It is possible to eliminate the inconvenience due to the collision between the tooth tips. That is, both gears 14,14
The R, 14B and 111 teeth are formed by cutting out the part indicated by the chain line from the normal tooth profile. If you do this,
The developing roller gear 14, 14R or 14B is the center O of the developing unit.
When engaging the drive gear 111 while revolving in the direction of the arrow Q, even if the tooth tips of both gears come into contact with each other, the linear tip portions 118 of the gears abut each other, so that the tooth tips immediately The abutment is released and the normal meshing state is established. The teeth of both gears are cut on one side and the other flank is the same as the normal tooth profile, so during normal developing operation,
The driving force of the driving gear 111 can be transmitted to the developing roller gear without any trouble. It is particularly advantageous to use the configuration of FIG. 21 in combination with the configuration described above.

As explained above, when the toner in the toner tank of the toner supply device becomes empty or becomes small, a new toner tank must be replaced, but this must be notified to the operator. The configuration related to this will be clarified below.

Small holes 57 formed in the toner tank 51 shown in FIG.
The total area of is constant. Therefore, the amount of toner sent by one rotation of the rotator 53 is almost constant. In other words, the amount of toner remaining in the toner tank 51 decreases as the number of rotations of the rotating body 53 increases. Utilizing this, it is known that the toner in the toner tank 51 has become empty or a small amount, and therefore the toner tank 51 should be replaced, depending on the number of operations or the operation amount of the rotating body 53 or the operating element related thereto. be able to.

FIG. 22 shows a toner replenishing motor for the drive gear 56 (FIG. 4), which is driven through the drive circuit 120 based on a command from the main controller 119 provided on the copying machine main body, and this gear. A toner replenishing solenoid 56b for engaging 56 with the intermediate gear 55, and an indicator 121 for displaying the toner end.
FIG. 23 is a block diagram showing an outline of FIG. 23, and FIG. 23 is a flowchart showing an example of an operation relating to toner end display.

In FIG. 23, when the toner replenishment signal is generated as described above (FIG. 23 (a)), the toner replenishment solenoid 56b.
Is urged, the rotating body 53 starts to rotate, and toner is replenished (FIG. 23 (b)). At this time, the number of times the toner supply solenoid 56b is operated is counted (+1) by the preset counter (FIG. 23 (c)). The same operation is repeated each time a toner replenishment signal is output, toner is replenished each time, and the count value of the preset counter is incremented by one. When the count value of this counter reaches a predetermined end number, the predetermined end number when the toner in the toner tank 51 is immediately empty or falls below a predetermined amount (Fig. 23 (d)) , A toner end signal is generated, and thereby the display device 121 is operated, and a toner end display indicating that the toner tank should be replaced is displayed on the display device (FIG. 23 (e)).

In this way, the operator can be notified that the toner tank 51 should be replaced. In this case, the above operation is sufficient if the number of developing devices is one and the developer chamber to which toner is to be replenished is one. However, when there are a plurality of developing devices as in the example of the drawing, the second operation is performed. Since the toner is also replenished to the third and third developing units 3R and 3B, the toner replenishing solenoid 56b is operated even when the toner is supplied to the developer chambers 4R and 4B of the second and third developing units 3R and 3B. Operate. Therefore, in this case, it is identified which toner supply solenoid 56b has been operated to supply toner to which developing device, and the number of times the solenoid has been operated for each toner supply device is separately counted by a counter. The value is compared with a predetermined end count, and toner end display is performed. Therefore, as shown in FIG. 22a, the replacement times are displayed on the display devices 121a, 121b, 121c for the toner tanks of the toner replenishing devices corresponding to the developing devices 3, 3R, 3B, respectively.

The number of operations of operating members other than the toner replenishing solenoid, for example, the number of rotations of the rotating body 53, the number of operations of the lever 56a or the number of operations of a motor for driving the same is stored (count).
However, the toner end may be displayed by an output signal generated when the number of rotations reaches a predetermined number of rotations.

The embodiment shown in FIG. 24 is slightly different from the embodiment shown in FIG.
A feeding screw shaft 217 that conveys the toner from the toner tank of the toner replenishing device to the developer chamber 4 is provided not inside the impeller 16 but inside the replenishing pipe 122 made of a non-magnetic material and extending parallel to the developing roller 10. Has been done. Therefore, the front skin end of the supply pipe 122 is inserted into the toner tank 51 just like the supply pipe 20 shown in FIG. The developer carried by the sending screw shaft 24 to the outside of the developer chamber 4 is transferred to the sending screw shaft 17 in the impeller 16 and is carried to the developer chamber 4 by this shaft 17 and, if necessary, the flow path. Although the developer is discharged to the outside of the developing device by the operation of the switching means, there is no difference from the previous embodiment, but the toner in the toner tank 51 is not carried to the developer chamber 4 by the feeding screw shaft 17. .

As described above, the developer chamber 4 passes through the replenishment toner replenishment pipe 122.
However, the toner generally has poorer fluidity than the carrier. Therefore the feed screw shaft
When only the toner flows in the replenishment pipe 122 due to the rotation of 217, the transportability is deteriorated. Therefore, as shown in FIGS. 24 and 25, a large number of developer inlets 123 arranged in the longitudinal direction of the replenishing pipe 122 are bored in the upper region of the replenishing pipe 122. The developer is introduced, and by rotating the feeding screw shaft 217, the taken-in developer and the toner replenished from the toner tank are mixed and stirred. Since the carrier is present in the taken-in developer, the developer containing the replenishment toner stirred in the replenishment pipe 122 has an increased fluidity and is smoothly conveyed in the replenishment pipe 122. Next, the developer thus agitated is formed in the lower region of the replenishing pipe 122, is discharged out of the pipe through a large number of outlets 124 arranged in the longitudinal direction, and is supplied to the developer chamber 4.

Further, in the configuration shown in FIGS. 24 and 25, the magnet 21 provided inside the developing roller 10 is magnetized in the following manner as in the case of FIG. That is, the developing roller 10
Two same poles (S poles in the example of the figure) are adjacent to the magnet portion T corresponding to the downstream side of the developing area D in the rotation direction of. Therefore, the developer that has passed through the developing area D and is carried to the portion of the same polarity receives a repulsive force in the direction away from the developing roller 10 due to the magnetic force of these magnets, and the roller 10
Is peeled from the surface. The developer inlet 123 of the replenishing pipe 122 is opened downward facing the peeling position. Therefore, the developer repelled from the developing roller 10 and peeled off is positively taken into the replenishing pipe 122. The developer separated from the developing roller 10 has a small amount of toner component immediately after passing through the developing area D (large amount of carrier component).
Since the developer has a low concentration, the ratio of the carrier component of the developer taken into the replenishment pipe 122 can be increased, and thus the fluidity thereof can be effectively improved. Moreover, the toner can be effectively stirred and supplied to the low-concentration developer separated from the developing roller 10. The developer flowing out from the supply pipe 122 is agitated by the impeller 16 and scattered around it. To enhance this scattering effect, impeller 16
A wire (not shown) may be spirally wound around and fixed to the outer periphery of the blade so that the developer is fed in a direction perpendicular to the paper surface of FIG.

By making the magnetic poles adjacent to each other the same as described above, instead of forming a peeling means for peeling the developer on the developing roller, peeling is performed by a separator that scrapes off the developer on the developing roller 10 as known per se. Even when the means is configured, the same effect can be obtained by disposing the intake port 123 of the supply pipe 122 so as to face the peeling position.

In addition, the feed screw shaft 217 provided inside the supply pipe 122
If part or all of the
Since the screw shaft 217 is magnetized by the magnetic pole, the magnetic force can positively attract the developer to the shaft 217, and the amount of the developer taken into the supply pipe 122 can be increased. This makes it possible to further increase the fluidity of the developer in the tube 122. Screw shaft 21 made of magnetic material
The above effect can be obtained by arranging 7 within the range of the magnetic force of the magnet 21, and therefore the replenishment pipe 122 may be arranged only in an appropriate magnetic field other than below the developer peeling position.

The above-mentioned configuration related to FIG. 21 and FIG.
The same applies to R and 3B, but this configuration can also be applied to a developing device including one developing device.

Of course, the present invention can be widely applied to image forming apparatuses other than copying machines, for example, developing devices such as printers.

Advantageous Effects of Invention The present invention forms the outer peripheral surface of at least one end wall of the two end walls defining the both ends of the developer chambers of the plurality of developing devices in the developing unit into a cylindrical shape, and forms at least two of the outer peripheral surfaces. Since the portion is supported by the support piece, the developing unit can be surely supported rotatably even if various elements of the developing device or other devices are located outside the end wall of the developing unit. . Moreover, since the portion supported by the support piece is the end wall of the developing unit, there is no need to provide a dedicated supported member, and the cost of the developing unit can be reduced. It is also possible to prevent the structure from becoming large.

[Brief description of drawings]

1 is a vertical cross-sectional view of the developing device when the developing unit is set in the main body of the copying machine, and FIG. 2 is II-II of FIG.
FIG. 3 is a cross-sectional view taken along the line, in which a portion of the toner supply device is cut along the line II′-II ′, FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1, and FIG. 3a is a guide member. FIG. 4 is a perspective view showing the state of the guide fins and the guide fins, FIG. 4 is a perspective view showing a state where the storage unit is pulled out from the copying machine main body, and the developing unit is removed from the storage unit. FIG. FIG. 5a is an exploded perspective view of the supply device, FIG. 5a is a perspective view of a device for switching the flow path of the developer, and FIG. 6 is VI-VI of FIG.
FIG. 7 is a partial perspective view showing another example of the toner supply device, and FIG. 8 is a seventh sectional view showing a state in which a supply pipe is inserted.
FIG. 9 is a cross-sectional view taken along the line VIII-VIII, FIG. 9 is a perspective view of the storage stand and the elements related thereto when the developing unit is removed, as seen from the back side, and FIG. FIG. 11 is a cross-sectional view showing another embodiment, FIG. 11 is a view for explaining the situation when the positioning pin is fitted in the positioning hole, FIG. 12 is a perspective view showing a mechanism for vertically moving the movable support roller, and FIG. FIG. 14 is an explanatory view for explaining the rotating operation of the developing unit, FIG. 14 is a view seen in the direction of the arrow Y in FIG. 13, FIG. 15 is an explanatory view showing the positional relationship of the developing roller gear, the drive gear, the sensor, etc. Figure is an explanatory view showing the cam and stop roller as seen from the front side, Figure 17 is an explanatory view showing the inconvenience when the centers of the gears are not arranged in a straight line, and Figure 18 is another arrangement of the gears. FIG. 19 is an explanatory view for explaining the abutment between the tooth tips,
FIG. 20 is a flow chart showing an operation example when a developing device is selected, FIG. 21 is an explanatory diagram showing another embodiment for canceling the abutment of the tooth tips of two gears, and FIG. 22 is a main controller. FIG. 22a is a schematic block diagram showing the elements controlled by this, and FIG. 22a is an explanatory diagram of a display for displaying the toner end of each developing device.
FIG. 23 is a flow chart showing an operation example of the toner tank replacement timing display, FIG. 24 is a sectional view of a developing unit in another embodiment, and FIG. 25 is a sectional view taken along the line WW in FIG. 1 ... Development unit 3,3R, 3B ... Developer 4,4R, 4B ... Developer chamber 7,8 ... End wall 9,9R, 9B ... Developer

Claims (1)

[Claims] 1. A developing operation comprising a plurality of developing devices containing a developer, each developing device occupying a predetermined developing position to visualize an electrostatic latent image formed on a latent image carrier. In a rotary developing device comprising a developing unit rotatably supported so as to face a latent image carrier, both ends of a developer chamber of a plurality of developing devices in the developing unit are partitioned. The developing device, wherein at least one of the two end walls has an outer peripheral surface formed in a cylindrical shape, and at least two places on the outer peripheral surface are rotatably supported by a support member.