JP2006010758A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device with which a rotating body in a locked state in a developer storing part can be rotated by effectively using the output torque of a motor. <P>SOLUTION: Rotation transmitting members 1 (1A to 1C) are arranged between the rotary shafts 3 (3A to 3C) of stirring members 12 and 10 and a developing roller 11 which are rotatably supported inside the developer storing part 13 and a driving motor 8. Circular-arc-shaped grooves 4 and 5 centering the rotary shaft 3 are formed on the rotation transmitting members 1 (1A to 1C). Meanwhile, projections 6 and 7 presenting shape gently fit in the grooves 4 and 5 are formed on a gear 2 (2A to 2C) connected to the driving motor 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device that develops an electrostatic latent image formed on an image carrier into a visible image.

  A developing device that supplies a developer to the surface of the image carrier includes a developer accommodating portion for accommodating the developer. The developer in the developer container is appropriately stirred and then supplied to the surface of the image carrier via the developing roller.

  However, when the developer in the developer container is solidified to form a lump, there is a case where the supply of the developer to the image carrier is hindered. One cause of the solidification of the developer is that a large amount of developer stays in the developer container.

Therefore, in the prior art, a torque limiter is connected to the rotating shaft of the agitating / conveying member that conveys the developer into the developer accommodating portion, and when the load applied to the rotating shaft is large, the agitating / conveying member automatically rotates. There is a developer replenishing device having a configuration of stopping. According to such a configuration, a large amount of developer is prevented from staying in the developer accommodating portion, and the occurrence of solidification of the developer can be prevented.
JP-A-3-67283

  However, in the developer replenishing device according to Patent Document 1 described above, no countermeasure is taken when the developer is actually solidified in the developer container. For this reason, when the developer in the developer accommodating portion is solidified, the stirring member is locked due to an overload, and the apparatus may not operate properly.

  In general, in order to prevent the developer in the developer container from solidifying, it is recommended that the user shake the developer container well before use, but this method bothers the user. It will be.

  Further, it is possible to loosen the developer by rotating the stirring member using a powerful motor, but there is a disadvantage that the cost increases as the output torque of the motor increases.

  An object of the present invention is to provide a developing device that makes it easy to rotate a rotating body in a locked state in a developer container by effectively using the output torque of a motor.

  The present invention has the following configuration.

(1) a developer accommodating portion for accommodating a developer;
A rotating body rotatably supported inside the developer containing portion;
A drive motor for supplying a rotational driving force to the rotating body;
A rotation transmission means for transmitting a rotational driving force from the drive motor to the rotation shaft of the rotating body after the drive motor has rotated a predetermined amount when the rotation shaft of the rotating body is connected to the drive motor;
It is provided with.

  The developing device according to the present invention includes a developer container, a rotating body, a drive motor, and a rotation transmission unit. The rotating body rotates inside the developer accommodating portion by a rotational driving force supplied from a driving motor. Examples of the rotating member include a stirring member that stirs the developer and a developing roller that supplies the stirred developer to the image carrier.

  The drive motor and the rotating body are connected via rotation transmitting means. The rotation transmitting means transmits the rotational driving force of the drive motor to the rotating body after the drive motor has rotated a predetermined amount. This takes into consideration that a large torque is required to rotate the rotating body depending on the developer accommodation state in the developer accommodating portion. When the rotation transmission means causes the drive motor to idle by a predetermined amount, when the drive motor is accelerated to some extent, a load for rotating the rotating body is applied to the drive motor. As a result, the rotating body can be easily rotated without increasing the output torque of the drive motor.

(2) The rotation transmission means includes a first member having a groove formed in an arc shape centering on a rotation axis of the rotating body;
A second member having a protrusion that is movable in the circumferential direction in the groove,
The rotating body and the drive motor are connected to each other through the first member and the second member that are in contact with each other.

  In this configuration, the rotation transmitting means includes a first member and a second member that are in contact with each other. The 1st member has the groove | channel formed in circular arc shape on the concentric circle of the rotating shaft of a rotary body. The second member has a protrusion that is movable in a groove formed in the first member.

  The groove is formed so that the circumferential length is a predetermined length. The circumferential length of the groove corresponds to the distance that the drive motor rotates without receiving a load from the rotating body. For this reason, it becomes easier to accelerate the drive motor as the circumferential length of the groove increases, and it becomes easier to rotate the rotating body against the load.

(3) The drive motor selectively rotates forward and reverse.

  In this configuration, the rotation direction of the drive motor can be switched between the forward rotation direction and the reverse rotation direction.

(4) An elastic member is disposed at an end of the groove in the circumferential direction.

  In this configuration, the elastic member is disposed at the circumferential end of the groove formed in the first member of the rotation transmitting means.

(5) A plurality of the rotating body and the rotation transmitting means are provided.
The circumferential lengths of the grooves formed in the first member of the plurality of rotation transmitting means are different from each other.

  In this structure, it forms so that the circumferential direction of the groove | channel of the 1st member corresponding to each rotary body in a some rotary body may mutually differ. The reason why the circumferential lengths of the grooves are made different in this way is to prevent the load of each rotating body from being simultaneously applied to the drive motor.

(6) The plurality of rotating bodies include a stirring member that stirs the developer, and a developing roller that supplies the developer stirred by the stirring member to the image carrier,
The circumferential length of the groove formed in the first member of the rotation transmitting means disposed between the rotation shaft of the developing roller and the drive motor is the longest.

  In this configuration, the circumferential direction of the groove of the first member corresponding to each rotating body in the plurality of rotating bodies is formed different from each other, and the circumferential direction of the groove of the first member connected to the developing roller Is set to the maximum length. This is for the purpose of transmitting the rotational driving force from the driving motor to the developing roller with the latest delay.

  According to the present invention, the following effects can be obtained.

(1) By effectively using the output torque of the drive motor, the locked rotating body can be easily rotated in the developer accommodating portion.

(2) The output torque of the drive motor can be used more effectively simply by interposing a member having a simple configuration between the drive motor and the rotating body.

(3) The idling distance of the drive motor can be earned by rotating the drive motor in the reverse direction.

(4) It becomes easy to absorb the impact when the load of the rotating body is transmitted to the drive motor.

(5) At the same time, it is possible to prevent a large load from being transmitted to the drive motor.

(6) At the same time, the load from the developing roller and the stirring member can be prevented from being transmitted to the drive motor. In addition, since the developing roller does not easily rotate in the reverse direction, the developer is less likely to leak from the developer container.

  Hereinafter, embodiments of the developing device of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 100 to which a developing device of the present invention is applied.

  The image forming apparatus 100 forms an image on a sheet through an electrophotographic image forming process. The image forming apparatus 100 includes paper feed cassettes 102 and 103 at the bottom and a paper discharge tray 104 at the top. A paper transport path F <b> 1 is provided between the paper feed cassettes 102 and 103 and the paper discharge tray 104. A photosensitive drum 105 is disposed in the vicinity of the paper transport path F1.

  Around the photosensitive drum 105, a charging device 106, an optical scanning unit 107, a developing unit 108, a transfer device 109, a cleaning unit 110, and a static elimination device (not shown) are disposed. The charging device 106 charges the outer peripheral surface of the photosensitive drum 105 to a predetermined potential. The optical scanning unit 107 forms an electrostatic latent image on the outer peripheral surface of the photosensitive drum 105 based on image data input from the outside. The developing unit 108 supplies toner onto the outer peripheral surface of the photosensitive drum 105 to visualize the electrostatic latent image, and forms a toner image.

  A registration roller 111 is disposed upstream of the photosensitive drum 105 in the sheet conveyance direction. The registration roller 111 adjusts the timing of supplying paper to the transfer position between the photosensitive drum 105 and the transfer device 109. A fixing device 112 is disposed downstream of the photosensitive drum 105. The fixing device 112 fixes the toner image transferred on the paper to the paper with heat and pressure.

  The image forming apparatus 100 includes a reverse conveyance path F2 that reverses the front and back of the paper and conveys it to the transfer position in order to form an image on the back side of the paper on which an image is formed on one side. Further, the image forming apparatus 100 includes a paper transport path F3 that joins the paper transport path F1 between the paper feed cassettes 102 and 103 and the transfer position. The paper transport path F3 is provided substantially horizontally. The paper conveyance path F3 leads to a manual feed tray 113 provided on the side surface of the image forming apparatus 100 and a paper receiving unit 114 that receives paper supplied from an external device, and is supplied from the manual feed tray 113 or the paper receiving unit 114. The conveyed paper is conveyed to the transfer position.

  FIG. 2 is a block diagram illustrating a schematic configuration of a main part of the image forming apparatus 100. The image forming apparatus 100 includes a CPU 150, a RAM 151, a ROM 152, an image processing unit 153, an image forming unit 154, and a sheet conveying unit 155. The RAM 151 is a non-volatile memory and is used for temporary data storage. The ROM 152 stores a program necessary for the operation of the image forming apparatus 100. The image processing unit 153 performs image processing according to a predetermined procedure on the input image data. The image forming unit 154 executes an image forming process on the paper based on the image data received from the image processing unit 153. The image forming unit 154 includes a drive motor 8 and a clutch 9. The sheet conveying unit 155 conveys paper to the image forming unit 154.

  FIG. 3 is a diagram showing a schematic configuration of the developing unit 108. The developing unit 108 includes a developer accommodating portion 13 that accommodates the developer. An opening is formed on the photosensitive drum 105 side in the developer accommodating portion 13. A developing roller 11 for supplying the developer in the developer accommodating portion 13 to the photosensitive drum 105 is disposed in the opening. Agitating rollers 10 and 12 for agitating the accommodated developer are disposed in the developer accommodating portion 13. In the present embodiment, the developing roller 11 and the stirring rollers 10 and 12 constitute the rotating body of the present invention.

  FIG. 4 is a plan view showing a schematic configuration of the developing unit 108. A rotation transmission member 1 </ b> A is attached to one end of the rotation shaft 3 </ b> A of the stirring roller 12. Similarly, the rotation transmission member 1B is attached to one end of the rotation shaft 3B of the stirring roller 10, and the rotation transmission member 1C is attached to one end of the rotation shaft 3C of the developing roller 11.

  The drive motor 8 is a motor whose rotation direction can be switched between forward and reverse. A clutch 9 is connected to the drive motor 8, and the rotational driving force of the drive motor 8 is transmitted to the gear 2 </ b> A via the clutch 9. The gear 2A meshes with the gear 2B, and the gear 2B further meshes with the gear 2C. For this reason, the rotational driving force of the drive motor 8 is transmitted to each of the gear 2A, the gear 2B, and the gear 2C via the clutch 9.

  In the present embodiment, the rotation transmission member 1A is interposed between the gear 2A and the rotation shaft 3A, the rotation transmission member 1B is interposed between the gear 2B and the rotation shaft 3B, and the gear 2C and the rotation shaft are interposed. The rotation transmitting member 1C is interposed between the 3C.

  FIG. 5 is a diagram illustrating a connection state between the gear 2 (2A to 2C) and the rotation transmission member 1 (1A to 1C). The gear 2 and the rotation transmission member 1 are in contact with each other as shown in FIG. A groove 4 (4A to 4C) and a groove 5 (5A to 5C) are formed on the contact surface of the rotation transmitting member 1 with the gear 2. The grooves 4 and 5 have an arc shape centered on the rotation center of the rotation shaft 3 (3A to 3C). The circumferential lengths of the grooves 4A, 4B, and 4C are different from each other, the groove 4C being the longest, the groove 4B being the next longest, and the groove 4A being the shortest. Similarly, the circumferential lengths of the grooves 5A, 5B, and 5C are different from each other, the groove 5C being the longest, the groove 5B being the next longest, and the groove 5A being the shortest. Elastic members (not shown) are disposed at both ends in the circumferential direction of the grooves 4 and 5. The depths of the grooves 4 and 5 may be deep enough to allow the projections 6 and 7 to be described later to be sufficiently fitted, and the grooves 4 and 5 may be formed so as to penetrate the rotation transmitting member 1.

  On the other hand, the gear 2 is formed with protrusions 6 (6A to 6B) and protrusions 7 (7A to 7C). The protrusion 6 (6A to 6B) has a shape that fits gently into the groove 4, and the protrusion 7 (7A to 7C) has a shape that fits gently into the groove 5.

  The protrusions 6 (6A to 6B) and the protrusions 7 (7A to 7C) formed on the gear 2 are circumferential with respect to the ends of the rotation direction of the gear 2 in the circumferential direction of the grooves 4 and 5 of the rotation transmitting member 1. By applying a directional force, a rotational driving force is transmitted from the gear 2 to the rotating shaft 3.

  In the developing unit 108, when the operation stops, the drive motor 8 is reversed to separate the protrusions 6 and 7 from the end portions of the grooves 4 and 5 on the traveling direction side of the gear 2. At this time, the projections 6 and 7 are easily separated from the end portions of the grooves 4 and 5 on the traveling direction side of the gear 2 by force from an elastic member (not shown) at both ends in the circumferential direction of the grooves 4 and 5. In this way, by preparing to idle the drive motor 8, it is possible to idle the drive motor 8 before the load from the rotary shaft 3 is applied to the drive motor 8. This idling preparatory work is preferably performed when a new toner cartridge is mounted, when the image forming apparatus 100 is turned on, or when operation is resumed after interruption of processing.

  Conventionally, the output torque when starting the drive motor 8 has been used for both the acceleration of the drive motor 8 itself and the rotational drive of the rotary shaft 3, but in this embodiment, the grooves 4 and 5 are used. By accelerating the drive motor 8 before the load is applied by the drive motor 8, the output shaft of the drive motor 8 can be used more efficiently to drive the rotary shaft 3.

  Finally, the description of the above-described embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

1 is a diagram showing a schematic configuration of an image forming apparatus to which a developing device of the present invention is applied. 1 is a block diagram illustrating a schematic configuration of a main part of an image forming apparatus. It is a figure which shows schematic structure of a developing unit. It is a top view which shows schematic structure of a developing unit. It is a figure which shows the connection state of a gear and a rotation transmission member.

Explanation of symbols

1 (1A to 1C) -Rotation transmission member 2 (2A to 2C) -Gear 3 (3A to 3C) -Rotating shaft 4,5-Groove 6,7-Protrusion 8-Drive motor 9-Clutch 10-Agitating member 11- Developing roller 12-stirring member

Claims (6)

A developer accommodating portion for accommodating the developer;
A rotating body rotatably supported inside the developer containing portion;
A drive motor for supplying a rotational driving force to the rotating body;
A rotation transmission means for transmitting a rotational driving force from the drive motor to the rotation shaft of the rotating body after the drive motor has rotated a predetermined amount when the rotation shaft of the rotating body is connected to the drive motor;
A developing device comprising: The rotation transmitting means includes a first member having a groove formed in an arc shape around the rotation axis of the rotating body;
A second member having a protrusion that is movable in the circumferential direction in the groove,
The developing device according to claim 1, wherein the rotating body and the drive motor are connected via the first member and the second member that are in contact with each other.   The developing device according to claim 1, wherein the drive motor selectively rotates forward and backward.   The developing device according to claim 2, wherein an elastic member is disposed at an end of the groove in the circumferential direction. A plurality of the rotating body and the rotation transmitting means;
The developing device according to claim 2, wherein the circumferential lengths of the grooves formed in the first member of the plurality of rotation transmitting units are different from each other. The plurality of rotating bodies include a stirring member that stirs the developer, and a developing roller that supplies the developer stirred by the stirring member to the image carrier,
The circumferential length of the groove formed in the first member in the rotation transmission means disposed between the rotation shaft of the developing roller and the drive motor is longest. Development device.

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