JP3479849B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile and a printer, and more particularly to an improvement of a rotary positioning mechanism of a rotary developing unit having a plurality of developing devices as moving bodies. is there.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus of this type, a rotary developing device unit provided with a plurality of developing devices and rotatably provided in the vicinity of a photosensitive member as a latent image carrier is provided for each developing device. Is known to have a rotary developing device in which the latent image on the photoconductor is developed with toner of each color by sequentially rotating to a developing position opposite to the photoconductor (for example, Japanese Patent Laid-Open No. 62- No. 251772, JP-A-63-78170, and JP-A-63-41164).

In such an image forming apparatus, it is necessary to sequentially move each developing device to the developing position and position it accurately. Therefore, for example, a concave portion corresponding to each developing device is formed in the peripheral wall portion of the rear end wall of the rotary developing device unit, and a roller fitted into the concave portion is rotatably provided at a fixed position on the apparatus main body side.
Rotate the rotary developer unit by the amount of rotation necessary to make the recess corresponding to the developing device to be used face the roller provided at the fixed position on the main body side, and fit the roller into the recess. Therefore, it has been proposed to accurately position each developing device (see, for example, JP-A-63-78175).

[0004]

However, in such a structure, the required amount of rotation cannot be obtained due to variations in the motor for rotationally driving the rotary developing device unit and fluctuations in the load, so that the rollers have a predetermined recess. There was a case where it was not possible to fit in and accurate positioning could not be performed. In this case, the distance between the developing roller provided in the developing unit of the rotary developing unit and the photoconductor is different from the target distance, and the target image quality cannot be obtained. Not only the rotary developing device unit, but also other movable bodies in the image forming apparatus that require accurate positioning will also have problems if accurate positioning cannot be performed.

Therefore, the applicant of the present invention has previously proposed a rotary developing device unit rotatably attached to the apparatus main body, a developing rotary member movably attached to the rotary developing device unit, and a driving device for the rotary developing device unit. In response to a predetermined driving input to the developing rotary member, a rotational force is applied to the rotary developing device unit in a direction opposite to the movement of the rotary developing device unit in the predetermined direction by the driving device for the rotary developing device unit. And a developing rotary member driving device configured to obtain the rotational developing device unit, and the developing device cannot be positioned by engagement against the moving force of the rotary developing device unit in a predetermined direction by the driving device. A positioning device for a rotary developing device unit configured to enable positioning by engagement against the moving force in the opposite direction by a driving device for a rotary developing device, and a position of the rotary developing device unit. An image forming apparatus is proposed which is provided with a control means for controlling a driving device for the rotary developing device unit so that the movement in the direction is performed to such an extent that it exceeds the intended moving position of the rotary developing device unit ( April 1994
Patent application / reference number 9400611 submitted on 20th of March.

According to this image forming apparatus, the target moving position
Rotation of the rotary developer unit in the predetermined direction
The target moving position by the drive unit for the transfer developing unit
Drive to the developing rotary body after
The direction opposite to the predetermined direction of the rotary developing device unit
Aiming at the rotary developing unit by the moving force to
Returned to the position and reached the target moving position
With respect to the rotational developing unit, the moving force in the opposite direction
Stopping force that can stop the movement of the rotary developing unit against
For the above-mentioned rotary developer unit
The movement of the drive device in a predetermined direction is
Make sure to set the target moving position above considering
Target movement position even when set to a large movement amount that exceeds
Can be positioned. Therefore, variations and loads of the drive device
Accurately position the rotary developing unit regardless of fluctuations
Wear.

However, in the image forming apparatus according to this prior application, the magnitude of the moving force (rotational moment) in the direction opposite to the predetermined rotation direction of the rotary developing device unit by the drive unit for the developing rotary member. Depends on the distance between the rotary shaft of the rotary developing unit and the rotation shaft of the rotary developing unit, the drive of which is transmitted from the drive unit for the rotary developing unit, and if this distance is not sufficiently large, the desired moving force cannot be obtained. Because I can not get it,
The problem remains that the degree of freedom in setting the spindle position of the developing rotary member is narrowed.

The present invention relates to an improvement of the image forming apparatus according to this prior application, and an object of the invention is to utilize a driving input to a second moving body attached to the first moving body to perform rotation or the like. It is possible to accurately position the first moving body, which is attached to the main body of the apparatus so as to be capable of endless movement, at a predetermined moving position regardless of variations and load fluctuations of the drive device for the first moving body. (2) An object of the present invention is to provide an image forming apparatus in which the degree of freedom in setting the mounting position of a moving body can be relatively large.

[0009]

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention includes a first moving body attached to an apparatus body for endless movement such as rotation, and a first moving body. The second and third movable bodies movably attached to the movable body, the drive unit for the first movable body, and the drive unit for the first movable body with a predetermined drive input to the second movable body. A second structure configured to give a moving force in a direction opposite to the movement of the first moving body in a predetermined direction to the first moving body.
And the third moving body driving device and the first moving body driving device against the moving force of the first moving body in a predetermined direction, the positioning by engagement is impossible, and the second and the second moving body Three
A positioning device for a first moving body, which is configured to enable positioning by engagement against the moving force in the opposite direction by the two driving devices for the moving body, The control means for controlling the drive unit for the first moving body so that the movement in the predetermined direction exceeds the target moving position of the first moving body, and the movement in the predetermined direction of the first moving body are After the first moving object is moved to a position beyond the intended moving position, the second
And control means for controlling the drive devices for the third moving body so as to operate together.

[0010] The image forming apparatus according to claim 2, in the image forming apparatus according to claim 1, said first movable body is a rotary developing unit having a plurality of developing units, the second moving body, said plurality of Is a rotating body for development rotatably mounted in the developing device, wherein the third moving body drives the second moving body and the driving device for the second moving body in the rotary developing unit. A rotating body for replenishing toner, which is rotatably mounted in a replenishment toner accommodating portion provided on a side opposite to the connecting portion so as to correspond to each of the plurality of developing devices, and the positioning device includes: A plurality of engaged portions are formed at predetermined locations of the rotary developing device unit so as to correspond to the plurality of developing devices, and are provided on the apparatus main body side so as to engage the plurality of engaged portions. It is configured with It is an.

[0011]

According to the image forming apparatus of the present invention, in positioning the first moving body at the target moving position, first, the first moving body is moved in the predetermined direction toward the target moving position. The driving device for the moving body is used to the extent that the target moving position is exceeded. Then, the drive devices for the second and third moving bodies are actuated, and the moving force of the first moving body in the direction opposite to the predetermined direction causes the first moving body to move toward the target moving position. return. As a result, the first moving body that has reached the target moving position is positioned by applying a stopping force that can stop the movement of the first moving body against the moving force in the opposite direction. Here, the movement in the predetermined direction by the driving device for the first moving body is set to a large movement amount that is sure to exceed the target moving position in consideration of variations and load fluctuations of the driving device. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a color electrophotographic printer (hereinafter referred to as a printer) which is an image forming apparatus will be described below. FIG. 1 is a schematic configuration diagram of a printer according to this embodiment. First, an outline of the entire printer will be described. In FIG. 1, a photosensitive drum 1 serving as a latent image carrier is uniformly driven by a charging charger 2 serving as uniform charging means while being rotationally driven in the direction of arrow A, and then image information is generated by a laser optical device 3. Scanning exposure is performed on the basis of the above to form an electrostatic latent image on the surface. Here, the image information to be exposed is image information of a single color obtained by separating a desired full-color image into color information of yellow, magenta, cyan, and black. The electrostatic latent image formed on the photoconductor drum 1 is developed by the rotary developing device 4 described later with yellow, magenta, cyan, and black toners as predetermined developers, respectively. An image of each color is formed on.

Each color image formed on the photoconductor drum 1 is formed on the intermediate transfer belt 5 which rotates in the direction of arrow B in the figure in synchronization with the photoconductor drum 1 for each color of yellow, magenta, cyan and black. The primary transfer charger 6 sequentially performs the superimposed transfer. The yellow, magenta, cyan, and black images that are superposed on the intermediate transfer belt 5 are transferred from the automatic paper feed cassette 7 for double-sided copying or the manual paper feed tray 7a through the paper feed rollers 8 and 8a and the registration rollers 9. The secondary transfer charger 11 collectively transfers the transferred sheet 10 onto the transfer sheet 10. After the transfer is completed, the toner image is fixed on the transfer paper 10 by the fixing device 12, and the transfer paper 10 is discharged outside the machine as a full color print.

The toner on the photoconductor drum 1 that has not been transferred onto the intermediate transfer belt 5 is removed by the photoconductor cleaner 13.
Is removed from the photosensitive drum 1 by the
The toner on the intermediate transfer belt 5 that has not been transferred onto the
It is removed from the intermediate transfer belt 5 by the intermediate transfer belt cleaner 14.

Next, the rotary developing device 4 according to this embodiment will be described. 2 is an exploded perspective view of the developing device 4, FIG. 3 is a plan view of the developing device 4, and FIG. 4 is a partially enlarged perspective view of the developing device 4. In FIG. 2, the rotary developing device 4 is
For example, developing units for four colors of black, cyan, yellow, and magenta are formed inside, and a developing unit 40 having a substantially cylindrical outer periphery mounted rotatably around the central axis in the printer main body, and each developing unit. The four toner containers 41, 42, 43, and 44, which respectively correspond to the containers in one-to-one correspondence with the toners of black, yellow, magenta, and cyan, respectively, are held, and on the front side of the developing unit 40 in the central axis direction. A toner container unit 45 mounted so as to be substantially coaxial and rotating integrally with the developing device unit 40 around the central axis, and the developing device unit 40 and the toner container unit 45 (hereinafter referred to as a revolver developing unit). ), The storage stand 46 slidable on the printer body substantially parallel to the central axis and the rotation supply unit are covered. And a cover 47 provided non-rotatable.

The revolver developing unit is provided with a receiving table 46.
The disk-shaped front end wall 5 of the developing device unit 40 includes, for example, two support rollers 49 rotatably attached to the front support plate 48 of
0, and a central axis 52 of the tip end taper protruding from the center of the disk-shaped rear end wall 51 of the developing device unit 40.
Is rotatably supported by a central shaft insertion hole 54 formed in the rear plate 53 of the main body, so that the rotation axis of the main body is substantially the same as the rotation axis of the photosensitive drum 1 in the printer main body as shown in FIG. They are positioned so as to be parallel to each other in the same horizontal plane and are rotatable.

The housing base 46 has a front support plate 48, a rear support plate 55, and a side cover 59 having front and rear ends fixed to both support plates and reinforced by connecting rods 56, 57 and 58.
Have and. An insertion hole 60 into which the revolver developing unit can be inserted is formed in the front support plate 48, and in addition to the support roller 49, a motor 61 for driving a toner replenishing roller provided in the toner container unit 45 and the motor 61. A gear train 62 driven by a motor 61 is attached.
Further, as shown in FIG.
An intermediate plate 63 supported by the connecting rods 56 and 57 is attached in the vicinity of 5, and a positioning pin 63b that fits into a positioning hole 63a formed in the rear plate of the main body is provided in the intermediate plate 63 so as to project. A base end portion of a bracket 64 is swingably attached to a positioning pin portion between the intermediate plate 63 and the rear support plate 55, and a predetermined portion of the peripheral surface portion of the rear end wall of the developing device unit is attached to the front end portion of the bracket 64. A positioning roller 66 that falls into any of a plurality of (four in this example) recesses 65 formed at a location is rotatably supported. This bracket 64 is urged in the direction of the arrow by a spring 67, and when the recess 65 faces the roller due to the rotation of the revolver developing unit, for example, as shown by the broken line in FIG. 7, the roller is surely dropped into the recess 65. It is designed to fit. Positioning of the rotational position of the revolver developing unit using the recess 65 and the positioning roller 66 will be described later in detail.

On the other hand, a front plate 68 of the main body of the printer is provided with an insertion hole 69 or the like into which the above-mentioned storage stand 46 carrying a revolver developing unit can be inserted.
Upper and lower guides 70, 71 for slidably supporting the storage stand 46 are hung between the main body rear side plate 53 and the main body. Guided portions 72 and 73 are provided at the upper end and side portions of the storage table side cover 59 as the receiving table portion guided by these guides 70 and 71, and the lower surface portion of the guided portion 73 on the side of these is provided. The pin groove 7 into which the guide pin 74 planted upward in the guide 71 is inserted.
5 is formed. The pin groove is provided in the accommodating table 46 when the accommodating table 46 is inserted into or pulled out from the printer body.
The revolver developing unit so that the revolver developing unit can be guided to a predetermined position relatively close to the photosensitive drum 1 when the insertion is completed and the revolver developing unit can be guided away from the photosensitive drum 1. Then, the shape is bent so that it becomes closer to the photosensitive drum 1.

Further, the tip end of the positioning pin 63b projectingly provided on the intermediate plate 63 is tapered, and this tip end of the rear plate 53 of the main body immediately before the completion of insertion of the storage table into the printer main body. The rear support plate 55 of the accommodating base 46 can be accurately positioned in the main body when it is inserted into the positioning hole 63a and the insertion is completed. On the other hand, the front support plate 48 of the storage table 46 is fixed to the front plate 68 of the main body with screws 76 or the like after the insertion of the storage table 46 into the main body is completed. Instead of this, a tape-shaped positioning pin may be used similarly to the rear support plate 55. The rear end of the revolver developing unit is supported by the rear side plate 53 of the storage table 46 when the storage table 46 is pulled out. When the insertion is completed, it is gradually lifted up and completely lifted from the rear support plate 55. As a result, the revolver developing unit includes the support table 48 on the front of the accommodating base accurately positioned on the main body.
The front end portion is supported by the support roller 49, and the rear end portion is rotatably positioned by the main body rear side plate 53 through the central shaft 52 so that the rear end portion is rotatable.

The revolver developing unit is shown in FIG.
As shown in FIG. 7, a revolver rotation motor 7 which is attached to the main body rear side plate 53 and includes, for example, a stepping motor.
A revolver output gear 78, which is also mounted on the rear plate 53 of the main body, driven by 7, has a revolver input of approximately the same diameter as the rear end plate 51 fixed to the rear surface of the rear end plate of the developing device unit 40 by screws or the like. It is adapted to be meshed with the gear 79 to be rotationally driven. On the rear plate 53 of the main body, a developing drive motor 80 for driving a developing roller in the developing device unit 40 described later, a developing output gear 81 driven by the developing drive motor 80, each motor and each output gear. A gear box 82 and the like that accommodates a gear train 62 that connects the and are also attached. (Hereafter, margin)

FIG. 5 is a sectional view taken along line XX in FIG. 3 for showing the internal structure of the developing unit 40. The developing device unit 40 includes the above-mentioned substantially disk-shaped front and rear end plates (see FIG. 3), and partition walls provided between the front and rear end plates as shown in FIG. This partition wall is a hollow cylindrical portion 8 into which a cylindrical black toner bottle containing black toner can be inserted.
2 and developing device casing portions 83, 83C that radially extend from the hollow cylindrical portion 82 and divide the space around the hollow cylindrical portion 82 into four developing chambers of substantially the same type in the circumferential direction,
It consists of 83M and 83Y. Each of these developing chambers contains a carrier as a developer and a two-component developer including toner of each color. In the illustrated example, the developing position facing the photoconductor drum is the developing chamber of the black developing device containing the black toner and the carrier, and in the counterclockwise order in the figure, the yellow developing device containing the yellow toner and the carrier is arranged. A developing chamber, a developing chamber of a magenta developing unit containing magenta toner and a carrier, and a developing chamber of a cyan developing unit containing cyan toner and a carrier.

Since the internal structure of each of the four developing chambers is exactly the same, the internal structure of the black developing chamber in the developing position will be described below as an example in FIG. 5, and the internal structure of the other developing chambers will be described. Are the same reference numerals as the corresponding reference numerals in the black developing chambers, but with the suffixes Y, M, and C added to distinguish the yellow, magenta, and cyan developing chambers from each other. To do.

In the black developing device in the developing position in the figure, an opening portion facing the photosensitive drum 1 is formed in the developing device casing portion 83, and a part of the developing device is exposed through the opening portion in the developing chamber. A developing roller 84 is provided. Further, in the developing chamber, a doctor blade 85 which is carried by the developing roller 84 and regulates the amount of the developer conveyed to the portion facing the photoconductor drum 1, and the development which is regulated by the doctor blade 85 and pressed into the developing chamber An upper conveying screw 86 for conveying a part of the developer along the central axis direction from the front to the front and a guide 87 therefor, and a stirring paddle 88 for stirring the developer in the developing chamber are provided. The stirring paddle 88 has a plurality of developer discharge holes 89a across the width of the developing roller 84.
And a plurality of stirring plate portions 90 radially extending from the peripheral surface of the hollow cylindrical portion 89. The hollow cylindrical portion 89 is provided with the above-mentioned upper transfer along the central axis direction. A lower carrying screw 91 for carrying the developer in the opposite direction to the screw 86 is housed. The developer casing below the lower transport screw 91 serves as a deteriorated developer discharge port and, if necessary, an unused developer (toner-mixed) inlet when the developer is replaced due to the deterioration of development in the developing chamber. An agent discharge port 92 extending in the rotation axis direction for use is formed, and a cap 93 that covers the discharge port 92 from the outside is fixed by a screw 94 or the like.

Incidentally, in order to efficiently discharge the deteriorated developer from the discharge port 92, the revolver developing unit is placed in the receiving table 4.
6, the development input gear 95 (see FIG. 6), which will be described later, is rotated using a jig, and the developing roller 84, the vertical transport screws 86 and 91, and the paddle 88 are rotated to deteriorate the development. It is desirable to expel the agent. Further, even when the unused developer is introduced from the discharge port 92, the developer can be uniformly dispersed in the developer by rotating the developing roller 84, the upper and lower conveying screws 86 and 91, and the stirring paddle 88 in the same manner. .

FIG. 6 is a vertical cross-sectional view of a plane including the central axis 52 of the upper and lower conveying screws 86 and 91 of the black developing device. As shown in the figure, the front end portions of the vertical transport screws 86 and 91 extend outside the effective width region of the developing roller 84 (in the example shown, outside the front end wall 50 of the developing device unit), and this extension. A drop portion 96 for dropping the developer, which has been transported by the upper transport screw 86, onto the lower transport screw 91 by its own weight is provided at a position. The front end portion of the lower transport screw 91 extends further to the front side than the drop portion 96, and the toner container unit 45 described later in detail.
Toner supply roller 9 provided corresponding to each developing chamber
7 It extends to the communication room below. As a result, of the developer drawn up by the developing roller 84, the developer regulated by the doctor blade 85 and conveyed to the front side by the guide 87 and the upper conveying screw 86 is dropped onto the lower conveying screw 91 by the dropping portion 96. Then, it is conveyed by the lower conveying screw 91 within the effective width of the developing roller 84, and is discharged into the developing chamber from the developer discharge port of the stirring paddle hollow cylindrical portion within the width so that it can be carried by the developing roller 84 again. Become. That is, so-called lateral stirring of the developer is performed in the developing chamber. Then, the developer discharged from the developer discharge port of the hollow cylindrical portion 82 of the stirring paddle 88 to the developer pool at the lower portion of the developing chamber is so-called vertical stirring performed by the stirring plate portion by the rotation of the stirring paddle 88. Further, the toner dropped on the lower conveying screw 91 in the communication chamber by the rotation of the replenishing roller 97 is conveyed by the lower conveying screw 91 to the dropping portion 96, where it is taken into the developer dropped from the upper conveying screw 86. Are mixed with each other, and the mixed developer enters the developing chamber through the developer discharge port, thereby increasing the toner concentration of the developer in the developing chamber.

FIG. 7A is a perspective view of the rear end wall 51 of the developing device unit 40 seen from the front side. The revolver input gear 7 fixed to the rear end wall portion, specifically, the rear end wall 51.
The illustrated gears are provided on the rear side of the gear 9. That is, the developing roller gear 98 is fixed to the shaft end portion of the developing roller 84 that penetrates through the rear end wall 51 and the like and protrudes to the rear side of the revolver input gear 79. Vertical transport screw gears 99 and 100 are fixedly mounted on the respective shaft ends of the vertical transport screws 86 and 91 protruding to the rear side. In the illustrated example, the developing roller 84 gear and the lower carrying screw gear 10 are used.
Idle gear 101 meshing with 0 and the rear plate 53 of the main body
Development input gear 95 for meshing with a development output gear 81 which is attached to the
Is attached to the rear side of the rear end wall 51 of the developing device unit. As described above, the revolver developing unit in which these gears are provided on the rear end wall side is carried by the storage stand 46 and inserted into the printer main body, as shown in FIG.
As shown in (a), the development output gear 81 on the main body side meshes with the development input gear 95 on the revolver development unit side. At the same time, as shown in FIG. 7A, the revolver input gear 79 on the revolver developing unit side meshes with the revolver output gear 78 on the main body side.

FIG. 8A is a plan view of the drive motor section of the rotary type developing device, and FIG. 8B is a front view of the drive motor section. As can be seen from these figures, the gears 78, 81 on the main body side are retractable in the slide direction of the storage base so that the gears on the main body side and the revolver developing unit side are meshed well with the insertion of the storage base. Installed,
In addition, the springs 102 and 103 as biasing means push and bias it toward the front side of the main body. As a result, the gears 78 and 81 on the main body side and the gear 7 on the revolver developing unit side
Even when 9 and 95 interfere with each other when the storage table is inserted, the gears 78 and 81 on the main body side retract and the storage table 46 can be completely inserted. And the main body side gear 78 after that,
The interference of the gears can be eliminated with the driving of 81, and the main body gears 78, 8 are closest to the revolver developing unit side by the biasing force.
1 is pushed out, and the gear 79 on the revolver developing unit side,
Complete engagement with 95 can be realized.

In FIG. 7A in the state where the above complete meshing is realized, the developing output gear 81 is driven in the direction shown by the arrow A in the drawing, and the upper and lower conveying screw gears are engaged via the developing input gear 95 meshing with this. 99 and 100 rotate to rotate the upper and lower transport screws. Further, the developing roller gear 98 is rotated via the developing input gear 95, the lower carrying screw gear 100 and the idle gear 101, and the developing roller 84 is rotationally driven.

In the example shown in FIG. 5, the front and rear end wall portions that support the developing roller 84Y and the doctor blade 85Y are small enough to be separated from the other front and rear end wall portions as shown in the yellow developing device, for example. It is configured on the end wall portion 104. As a result, when cleaning the interior of the developing chamber or replacing parts,
The developing roller 84Y and the doctor blade 85Y are removed together with the small end wall portion 104 so that the developing chamber can be easily accessed.

Further, as shown in FIG. 7C, at a fixed position of the main body rear side plate 53 facing the end of the developing roller shaft 98a of the developing device positioned at the developing position, a developing bias for connecting to a bias circuit 105 is applied. The rod-shaped terminal 106 is attached by a bracket 107 so as to be retractable in the sliding direction of the storage table, and is pushed and urged toward the front side of the main body by a spring 107a as urging means. The tip portion of the rod-shaped terminal 106 is formed in a hemispherical shape, and the shaft end portion of the developing roller 84 is formed with an indentation having an arcuate cross section having a slightly larger radius of curvature than the hemisphere. It is possible to reduce the amount of additional contact when the shaft end portion of the developing roller 84, which reaches the portion facing the rod-shaped terminal 106 with the rotation, and the tip end of the rod-shaped terminal, and to reduce the contact and stabilize the contact during the engagement.

FIG. 9 is a sectional view taken along line YY in FIG. 3 for showing the internal structure of the toner container unit 45, and FIG.
11 corresponds to a sectional view of the toner container unit 45 when the black developing device is in the developing position. The toner container unit 45 includes a disk-shaped unit face plate 108.
(See also FIG. 2), and a total of four toner receiving cases 109Y, M, C, 110 mounted on the front surface of the face plate in a one-to-one correspondence with each developing device, and inside each toner receiving case. Toner replenishing rollers 97 provided in the respective
It has Y, M, C, 97 and the like. The toner replenishing roller is located almost directly above the extending portion of the lower conveying screw 91 into the case when the corresponding developing chamber is located at the developing position. Is supported by.

The unit face plate 108 is shown in FIG.
A circular through hole 111 through which a cylindrical black toner container as shown in (a) and (b) can pass is formed in the center thereof, and the toner receiving cases 109Y, M, and
C and 110 are attached by escaping the through hole 111. Further, the unit face plate 108 is also formed with through holes corresponding to the lower transport screw 91 extending from the developing chamber of each developing device and a trough-shaped screw cover 112 (see FIG. 10) provided as necessary. The lower conveying screw is provided with the toner receiving cases 109Y, M, C, 11 on the front surface of the unit face plate 108 through the through holes.
It extends within 0.

FIG. 10 shows a cyan toner receiving case 10.
9C and cyan toner container 44 attached thereto
Fig. 11 is a perspective view of Fig. 11, and Fig. 11 is a side view of these. The four toner receiving cases 109Y, M, C, 109
Among them, the three color toner receiving cases 109Y, M, C corresponding to the respective color developing devices have the same shape. That is, taking the case for receiving cyan toner as an example, as shown in FIG. 10, the toner is enclosed when the inwardly extending portion of the lower carrying screw 91 and the toner replenishing roller 97C are surrounded and the corresponding developing chamber is located at the developing position. A peripheral wall portion having a toner receiving port is formed at a position above the replenishing roller 97C, and a color toner container 44 having the same shape for each color containing color toner is provided around the toner receiving port. A color toner container mounting portion 113 is formed so as to face downwards and to be aligned with the toner receiving port. Further, a seal member 114C that seals between the toner supply roller 97C and the peripheral surface of the toner supply roller 97C is attached to the inner wall surface of the case facing the toner supply roller 97C. The seal and the toner replenishing roller 97C partition the inside of the toner container mounting portion 113 into the toner container side and the developing chamber side, and the seal and the toner replenishing roller 97C and the lower conveying screw 91C.
With the peripheral wall of the case that surrounds the
A communication chamber that communicates with the developing chamber of the corresponding developing device via the above-mentioned dropping portion is defined.

The color toner container mounting portion 113 is
As shown in FIG. 10 and FIG. 11, the toner container is made detachable by sliding in the rotation axis direction of the revolver developing unit, and the color toner container once attached is simply slid in the opposite direction, that is, toward the front. A pull-out prevention member 115 (see FIG. 11) that enters into the already mounted color toner container through the toner discharge port is provided so as not to be removed only by itself. When removing the mounted color toner container, the shutter member 117 for shielding the discharge port is inserted into the slit 116 formed at the discharge port of the color toner container and the pull-out prevention member 115 is pushed down to push down the color toner container. Evacuate from inside. Such a color toner container mounting portion 113
When setting a new color toner container in the printer, slide the color toner container with the sealing member attached to the toner outlet into the sealed state, and then remove the seal member to remove the toner. It is desirable to open the outlet.

Here, the color toner containers 42, 43,
Reference numeral 44 has a shape capable of fitting with a peripheral wall portion around the lower transporting screw 91 of the toner receiving case upstream of the corresponding toner receiving case in the rotation direction of the revolver developing unit, and of the rear end wall 51. Attached to the outer surface portion on the revolver developing unit side, for example, as shown in FIGS.
The protrusions 119Y, M, and C to be detected which are detected by the set detection device 118 as shown in FIG. The set detection device 118 shown in the figure has a through hole 12 formed in the unit face plate when the color toner container is set in the mounting portion.
A transmissive or reflective optical sensor 118Y attached to the rear surface of the face plate so that the tips of the protrusions 119Y, M, and C for detection that penetrate through 0 and project to the rear surface of the face plate can be detected. It is composed of M and C.

On the other hand, as shown in FIG. 9, the black toner receiving case 110 corresponding to the black developing device has the color toner receiving cases 109Y, M, and C with the color toner accommodating containers 42, 43, and 44 attached thereto. Both have a peripheral wall shape that is substantially the same as the overall peripheral wall shape. A peripheral wall portion having a shape similar to that of the color toner receiving case is also provided with a seal member 114 for sealing between the toner replenishing roller 97 and the inner wall surface of the case. A communication chamber with the developing chamber accommodating the extended portion of the screw 91 is formed. In addition, in the portion facing the center line of the revolver developing unit in the peripheral wall portion having the same shape as the color toner container, FIG.
A toner receiving opening 122 having a shape corresponding to the toner discharging opening 121 of the black toner container 41 as shown in FIGS.
Are formed. The toner received from the black toner container through the toner receiving port 122 has a peripheral wall portion having a shape similar to that of the color toner container and the toner supply roller 9.
The toner is stored in a region corresponding to a hopper in a normal toner replenishing device surrounded by 7 and the like, and is discharged into the communication chamber by rotation of the toner replenishing roller 97. The toner receiving port 122 can be closed from the inside by a shutter 124 whose one end is rotatably supported by a support shaft 123 parallel to the rotation shaft of the revolver developing unit. The shutter 124 swings around the support shaft 123 by its own weight as the revolver developing unit rotates, and automatically opens and closes the toner receiving port 122. Further, the toner receiving port 12 is provided at the edge of the shutter 124.
A seal member 125 for enhancing the shielding property of No. 2 is attached.

Further, the toner replenishing rollers 97Y, M,
C and 97 have a roller portion in which a plurality of grooves extending in the axial direction are formed on the peripheral surface portion as shown in FIG. 10, and are provided to the developing unit 40 side via the bearing portion of the unit face plate 108 as shown in FIG. A gear 135 is fixed to the shaft end portion that penetrates through, and a supplementary input gear 13 for driving input that meshes with the gear 135.
6 is fixed. Of the replenishment input gear 136 provided for each toner replenishment roller, the replenishment input gear 136 of the toner replenishment roller 97 in the case corresponding to the developing device in the developing position as shown in FIG. A gear 62 driven by a replenishment motor 61 attached to the front support plate 48 meshes with the gear 62 so that it can be rotationally driven by the motor 61.

In this embodiment, the drive device for driving the toner replenishing roller 97 is used for positioning the rotational position of the revolver developing unit. This point will be described in detail later. (Hereafter, margin)

Here, the black toner container 41 is shown in FIG.
As shown in (a) and (b), a toner discharge port 121 is formed on the peripheral wall portion at one end in the longitudinal direction, and a toner feed protrusion 126 is formed on the inner peripheral surface of the toner discharge port 121 from the other end. 1
It is formed in a spiral shape toward the 21 side. The spiral projecting portion 126 sends the stored toner from the rear end portion to the front end portion where the toner discharge port 121 is formed by the rotation integrally with the revolver developing unit when attached to the revolver developing unit. It is spiraled. Further, a protrusion 128 for detection is formed on the outer surface of the peripheral wall on the rear end side in the longitudinal direction from the toner discharge port 121, and the knob 12 is provided on the front end.
9 is provided. The detection projection 128 is shown in FIG.
By the set detection device 127 attached to the revolver developing unit side as indicated by the broken line, specifically, to the rear surface of the front support plate 48 of the accommodating base, the support shaft 123 is also attached to the rear surface of the front support plate 48. Link 1 swingably attached
Detected via 34.

That is, in the black toner container 41, the seal member that seals the toner discharge port 121 with the posture in which the toner discharge port 121 faces upward is removed, and the protrusion portion 1 for detection is detected.
28 passes through the passage notch 130 formed in the cover 47 shown in FIG. 2, and is inserted through the toner container insertion notch 47a of the cover 47 as shown by the broken line in FIG. The rear end portion is the hollow cylindrical portion 82 of the developing device unit 40.
It is inserted into the inside of the toner container unit 45 until it reaches the inside and is substantially flush with the front surface of the front end wall of each case of the toner container unit 45. Then, holding the knob 129, it is rotated clockwise in the drawing so that the toner discharge port coincides with the toner receiving port 122 of the black toner receiving case. At this time, the detected protrusion 128 engages with the link 134 on the revolver developing unit side to push it up and rotate it, and this rotation is detected by the set detection device, whereby the black toner container 41 is set. Is detected.

FIG. 13 is a block diagram of the electrical equipment of the printer body. The control device 160 of this electrical component includes a CPU, a RAM, a ROM, an I / O interface,
It is composed of a timer and the like. This controller 160
To the CPU of the home position sensor 151, the front cover detection device 152, through the I / O interface,
An optical sensor P (see FIG. 1) used for toner concentration control, and a set detection device 118 that is a replacement detection device for the toner container.
Y, M, C, 127, drive circuits 77a, 61a, 80a of various motors 77, 61, 80, and operation panel 161.
Etc. are connected. On the operation panel 161, toner near-end lamps 162Y, M, C, BK for displaying the toner near-end of each color developing device, and for the user instructing replacement of the toner accommodating containers 41, 42, 43, 44 of each color. Replacement instruction buttons 163Y, M, C, BK, a cover opening lamp 164 indicating that the front cover is opened, a ten-key 165, a print start button 166, and the like are provided. The home position sensor 151 shown in FIG.
As shown in FIG. 3, the revolver developing unit is attached to, for example, the front support plate 48 of the accommodating base so that the detected member 150 for home position detection can be detected. At the time of standby after the printing operation or after the printing operation, the home position position where the sensor 151 detects the detected member 150, that is, FIG.
The signal from the sensor 151 is used for the initial operation to keep the black developing device at a rotational position where the black developing device is located at the developing position as shown in FIG. To be

Next, the recess 65 of the revolver developing unit,
Positioning of the rotational position of the revolver developing unit using the positioning roller 66, the revolver driving motor 77, the developing drive motor 80, etc. will be described. In this embodiment, a revolver drive motor 77 including a stepping motor or the like.
7A, the revolver output gear 79 is driven to rotate in the direction of arrow B in the drawing to rotate the revolver developing unit in the direction of arrow C, thereby moving the revolver output gear 79 to the developing position. The revolver developing unit is positioned by inserting the positioning roller 66 into the recessed portion 65 formed at a predetermined position on the peripheral surface portion of the rear end wall 51 of the revolver developing unit for switching. Then, due to variations in the revolver drive motor and variations in the load on the revolver developing unit side, when the rotation angle of the revolver developing unit is a desired rotation angle (for example, when one upstream developing device in the rotation direction is moved to the developing position). However, the positioning roller 66 does not fit into the corresponding recessed portion 65 and accurate positioning cannot be performed, and the distance between the developing roller 84 and the photosensitive drum 1 is different from the desired distance. The following improvements have been added to prevent this.

In other words, the rotation control of the revolver drive motor 77 is controlled to correspond to an angle slightly larger than the desired angle (for example, an angle about 3 degrees larger) in consideration of the above variation so that the rotation of the revolver drive motor 77 can be reliably rotated at the desired angle. I am trying to use the value. As a result of controlling the rotation with such a control value, the revolver is started by driving the developing drive motor 80 and the replenishing motor 61 so that accurate positioning can be performed even when the revolver developing unit actually rotates beyond a desired angle. Accurate positioning can be performed by utilizing the rotation moment applied to the developing unit. Specifically, as shown in FIG. 7A, the development output gear 8 meshed with the development input gear 95 of the developing device in the development position.
By the rotation in the direction of arrow A in FIG. 1 (the rotation in the direction during normal development drive), a rotation moment in the direction opposite to the rotation direction of the normal revolver developing unit indicated by the outlined arrow D in the figure is generated. It is given to a unit so that the unit can be returned. Further, as shown in FIG. 14, the gear 62 of the toner replenishing roller driving device 140 meshing with the replenishing input gear 136 of the gear 135 fixed to the shaft end of the toner replenishing roller corresponding to the developing device in the developing position. Rotation in the direction of arrow E in the figure (rotation in the direction of normal replenishment operation)
As a result, the unit can also be returned by giving a rotational moment in a direction opposite to the direction of rotation of the normal revolver developing unit, which is indicated by an outlined arrow F in the figure, to the unit. The bracket 64 to which the positioning roller 66 is attached is rotated in the returning direction so that the return of the unit is stopped when the positioning roller 66 is fitted into the corresponding recess 65 to lock the rotation of the revolver unit. On the other hand, the position of the positioning pin 63, which is the bracket support shaft, and the contact position with respect to the revolver developing unit are determined so as to serve as a counter.

In the above-described structure, when the cyan developing device is located at the developing position from the home position where the black developing device is located at the developing position shown in FIGS. 5 and 9, it is necessary to rotate 90 degrees counterclockwise. is there.
At this time, in consideration of variations in the revolver drive motor 77, etc., the motor 77 is rotationally controlled by a control value that can surely rotate the revolver developing unit by 90 degrees or more, so that the concave portion 65 corresponding to the cyan developing device is slightly positioned. Rotate to the rotation position that passes through. Then, the developing drive motor 8
0 and the replenishment motor 61 are started to be driven, and the revolver developing unit is rotated in reverse by the rotational moment generated by this driving, and the positioning roller 66 is fitted into the recess 65. The positioning roller 66 exerts a strong stopping force to position the revolver developing unit.

In order to reduce the load of the drive system when the revolver developing unit rotates beyond the desired angle and exits the recess 65 that has once entered by the rotation control based on the above control value, FIG. As shown in the drawing, it is desirable that the inclination of the recessed portion 65a when the positioning portion comes out during the normal rotation is gentler than that of the locking recessed portion 65a to facilitate the removal.

Further, the replenishment input gear 136 mounted on the revolver developing unit side so as to mesh with the gear 135 fixed to the shaft end of the replenishment roller, and the toner replenishment roller driving device 140 mounted on the main body side. Gear 6
In order to prevent or mitigate the collision with the No. 2 when the revolver developing unit is brought into contact with or separated from the other by the rotation of the revolver developing unit, it is desirable to mount either one of them so as to be able to escape during the collision. For example, in the example of FIG. 14, the motor 61 or the like is attached to a bracket 141 in which the toner replenishing roller driving device 140 is rotatably attached to a support shaft 142 for a support roller 49 provided on a front support plate 48 of a storage stand. A spring that is attached and configured, and that swings the bracket 141 around the support shaft 142 so as to swing and bias the gear 62 toward the replenishment input gear 136 that is separated and brought into contact with by the rotation of the revolver developing unit. 143 is provided. As a result, in the event of collision of the replenishment input gear 136, the bracket 141
Of the two gears 62, 13
6 is prevented, and the gears 62 and 136 can be maintained in mesh with each other by the urging force of the spring 143. Moreover, in the illustrated example, the rotation of the replenishment roller 61 gives the bracket 141 an oscillating force in a direction in which the gear 62 bites into the replenishment input gear 136 side.

[0047]

According to the image forming apparatus of the first or second aspect, the movement of the first moving body in the predetermined direction toward the target moving position is moved by the drive unit for the first moving body. After the first moving body is driven to the extent that the first moving body is actuated, the driving devices for the second and third moving bodies are operated to move the first moving body by the moving force of the first moving body in the direction opposite to the predetermined direction. It is returned toward the aimed moving position, and a stopping force that can stop the movement of the first moving body against the moving force in the opposite direction is given to the first moving body that has reached the aimed moving position. Therefore, the movement in the predetermined direction by the driving device for the first moving body is set to a large movement amount that reliably exceeds the target moving position in consideration of variations and load fluctuations of the driving device. However, it can be positioned at the desired moving position. Therefore, the first moving body can be accurately positioned regardless of variations in the driving device and load fluctuations. Moreover, since the moving force in the opposite direction is obtained from both the driving devices for the second and third moving bodies, it is larger than that obtained from only the driving device for the second moving body, for example. It becomes possible to obtain a moving force (moment). Therefore, the distance between the moving center of the first moving body and the mounting positions of the second and third moving bodies on the first moving body is smaller than that obtained when only the drive unit for the second moving body is used. It becomes possible to set.

Particularly, according to the image forming apparatus of the second aspect, the first movable body is a rotary developing device unit having a plurality of developing devices, and the second and third movable bodies are the plurality of developing devices. A developing rotary member rotatably mounted in each of the container and the replenishment toner accommodating portion, and a toner replenishing rotary member, and the positioning device is provided at a predetermined position of the rotary developing device unit. It is composed of a plurality of engaged parts formed corresponding to the plurality of developing devices, and an engaging member provided on the apparatus main body side so as to engage with the plurality of engaged parts formed. , Each developing device can be accurately positioned at a predetermined developing position facing the latent image carrier. Therefore, an image of good quality can be formed by making the distance between the developing roller of the developing device and the latent image carrier a target distance.

Further, the side opposite to the drive connection portion between the developing rotary member and the drive unit for the rotary member in the rotary developing device unit, in which the replenishment toner accommodating portion is provided, is the above-mentioned part in the rotary developing device unit. Since the number of mounting members on the main body side is smaller than that on the side of the drive connecting portion, the mounting of the rotating body for toner replenishment in the accommodating portion itself or the intermediate transmission element itself attached to the accommodating portion so as to transmit the drive force thereto The degree of freedom in position setting is greater than that in setting the mounting position of the developing rotator or the like. Therefore, it is possible to attach the rotating body for toner replenishment, etc., far from the center of rotation of the rotary developing device unit.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of an electrophotographic printer according to an embodiment.

FIG. 2 is an exploded perspective view of a rotary developing device of the printer.

FIG. 3 is a plan view of the rotary developing device.

FIG. 4 is a partially enlarged perspective view of the rotary developing device.

5 is a sectional view taken along line XX in FIG.

FIG. 6 is an explanatory view of a connection structure between a developing device and a toner container in the rotary developing device.

FIG. 7A is a perspective view from the front showing a drive system of the rotary developing device. FIG. 3B is an explanatory diagram of a developing bias supply device for the developing device. (C) is explanatory drawing of the modification of the same rotary type developing device.

FIG. 8A is a plan view of a drive motor unit of the rotary developing device. (B) is a front view of the drive motor section.

9 is a sectional view taken along line YY in FIG.

FIG. 10 is a perspective view of a color toner container and a container mounting portion in the rotary developing device.

FIG. 11A is an explanatory view of a method of attaching the container to the container attachment portion. (B) is explanatory drawing of the same container set detector in the same attachment part.

FIG. 12A is a side view of a black toner container of the rotary developing device. (B) is a front view of the same container.

FIG. 13 is a block diagram of an electric component section of the printer.

FIG. 14 is an explanatory diagram of a toner supply roller driving device of the printer.

[Explanation of symbols]

1 photoconductor drum 61 Supply motor 62 gears 63 Positioning pin 64 bracket 66 Positioning roller 69 A recess formed in the rear end wall of the developing device unit 77 Revolver drive motor 78 revolver output gear 79 Gear at the rear end of the developing unit 80 Development drive motor 81 Development output gear 95 Development input gear 97 Toner supply roller 98 development gear 135 Toner supply roller gear 136 Supply input gear 140 Toner supply roller drive device 141 Toner supply roller drive device bracket 142 spindle 143 spring

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-27066 (JP, A) JP-A-63-78175 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 G03G 15/01 113

Claims (2)

(57) [Claims] 1. A first moving body which is attached to an apparatus main body so as to be capable of endless movement such as rotation, second and third moving bodies which are movably attached to the first moving body, and a first moving body. The drive device for the first moving body and the first driving input to the second moving body.
For each of the second and third moving bodies configured to give a moving force in a direction opposite to the movement of the first moving body in the predetermined direction by the driving device for the moving body to the first moving body Drive device and the drive device for the first moving body cannot perform positioning by engagement against the moving force of the first moving body in a predetermined direction, and both drives for the second and third moving bodies. A positioning device for the first moving body configured to enable positioning by engagement against the moving force in the opposite direction by the device; Control means for controlling the drive device for the first moving body so that the movement of the first moving body exceeds the target moving position of the first moving body, and the movement of the first moving body in a predetermined direction is the target movement of the first moving body. After the position is exceeded, the second and third
And a control unit for controlling the drive devices for the respective moving bodies so as to operate together. 2. The first moving body is a rotary developing device unit having a plurality of developing devices, and the second moving body is rotatably mounted in the plurality of developing devices. And the third moving body corresponds to each of the plurality of developing units on the side opposite to the drive connecting portion between the second moving body and the driving device for the second moving body in the rotary developing device unit. Is a rotating body for replenishing toner, which is rotatably mounted in a plurality of replenishing toner accommodating portions, and the positioning device is provided at a predetermined position of the rotating developing device unit. A plurality of engaged portions formed corresponding to the above, and an engaging member provided on the apparatus main body side so as to engage with the plurality of engaged portions formed. The image forming apparatus according to item 1 .