JP4455384B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus , particularly an image forming apparatus main body having a photosensitive drum. The image forming apparatus is detachably mounted and has a stirring member that is filled with a developer and stirs the developer. The present invention relates to an image forming apparatus provided with a developing unit to which an agent supply container is detachably attached.

Image forming apparatuses such as laser printers and copiers generally include an image forming apparatus body having a photosensitive drum on which a toner image is formed, and a developing unit that is detachably attached to the image forming apparatus body. ing. The developing unit includes a developing roller for supplying toner to the photosensitive drum for development, and a casing for rotatably holding the developing roller.

In this type of conventional image forming apparatus, when the developing unit is mounted on the image forming apparatus main body,
The developing roller is disposed adjacent to the photosensitive drum and is drivingly connected to the photosensitive drum. The developing roller is provided with holding members at both ends in the axial direction, and the distance from the photosensitive drum is kept constant. On the other hand, the casing is urged toward the photosensitive drum by the urging means provided on the image forming apparatus main body, so that the developing roller is not separated from the photosensitive drum as the photosensitive drum rotates. ing.

By the way, as a conventional developing unit, there is a type in which a separate toner container filled with toner is detachably mounted. The toner container includes an agitating member for agitating the toner and a drive gear that can rotate integrally with the agitating member. A drive roller for rotating the drive gear is held in the casing of the developing unit. The casing is provided with a fixing lever for fixing the toner container so that the attached toner container is not separated from the driving roller.

  As related techniques, those shown in the following Patent Documents 1 to 3 have already been proposed.

(For example, see Patent Documents 1 to 3).
JP-A-4-308872 JP 2004-37961 A JP-A-10-293464

In recent years, with the increase in capacity of toner containers, the torque applied to the stirring member tends to increase due to the weight of the toner. For this reason, when the driving roller starts to rotate, the driving gear connected to the stirring member tends to move away from the driving roller, and this force can be obtained only by fixing the toner container to the developing unit with the fixing lever. Can not be suppressed sufficiently.

In particular, depending on the pressure angle between the drive gear and the gear on the drive roller side and the way the toner container is guided in the developing unit, the toner container may be lifted from the casing, causing tooth skipping between the gears.

Therefore, in order to suppress such tooth skipping, a technique for suppressing rattling between the toner container and the developing unit has been proposed. In this case, however, the toner container cannot be attached and detached smoothly. Inconvenience arises.

An object of the present invention is to separate a developing roller from a photosensitive drum in an image forming apparatus including a developing unit of a type that is detachably attached to a main body of an image forming apparatus and a developer supply container is detachably attached. It is to suppress the separation of the developer supply container from the drive roller.

An image forming apparatus according to a first aspect includes an image forming apparatus main body, a developing unit, and a developer supply container. The image forming apparatus main body has a photosensitive drum. The developing unit is detachably attached to the image forming apparatus main body and can be disposed adjacent to the photosensitive drum, and is driven to rotate as the photosensitive drum rotates, and the photosensitive drum side And a holding portion for holding the developing roller at the first side end. The developer supply container is filled with a developer, has a stirring member for stirring the developer, and a drive gear that rotates integrally with the stirring member, and is detachably attached to the developing unit. The developing unit includes a mounting portion in which a developer supply container is detachably mounted at an end portion on a second side opposite to the photosensitive drum, and an opening portion is provided at an end portion on the second side. On the other hand, there is further provided a drive roller for driving the stirring member of the developer supply container disposed adjacent to the first side and mounted on the mounting portion via the drive gear . The image forming apparatus main body further includes a biasing unit that is disposed on the second side of the mounting portion and that can bias the developer supply container mounted on the developing unit through the opening of the mounting portion to the first side. Developer supply container is to have a portion to be urged for receiving a biasing force to the first side by the biasing means to an end portion of the second side, the driving gear is drivingly connected to the drive roller.

In this apparatus, when the developing unit is attached to the main body of the image forming apparatus, the developing roller is disposed adjacent to the photosensitive drum and is connected to be driven to rotate as the photosensitive drum is rotated. On the other hand, when the developer supply container is mounted on the developing unit, the stirring member is driven by the driving roller. At this time, the developer supply container is suppressed from being separated from the driving roller by being urged directly from the second side of the mounting portion to the first side by the urging means via the opening.
The developing roller is suppressed from being separated from the photosensitive drum by the developing unit being pressed toward the first side by the developing supply container that has received the biasing force toward the first side.

That is, here, the developer supply container is directly urged to the first side by the urging means, so that not only the photosensitive drum and the developing roller but also the developer supply container and the driving roller are separated from each other. Can be suppressed. Since the biasing means has an existing configuration in this type of conventional developing unit, there is no need to provide a special member, which is advantageous in terms of cost.

In the present invention, the first side includes, for example, the horizontal direction on the side where the photosensitive drum is located, and the second side in this case includes the horizontal direction opposite to the photosensitive drum. Therefore, when it is referred to as the first side with respect to a certain member, for example, it may be at least the first side from the center of the member (for example, the rotation center when the member is a roller), and the member is First
And it may be in the diagonal direction position which also displaces also in the side (for example, up-and-down direction) orthogonal to the straight line which passes the 2nd side.

  The image forming apparatus includes an image forming apparatus that is not equipped with a developer supply container.

In this apparatus, more specifically, the urging force of the urging means acts on the urged portion of the developer replenishing container, so that the photosensitive drum, between the developing rollers, and between the developer replenishing container and the driving roller. Separation can be suppressed.

The image forming apparatus according to claim 2 is the apparatus of claim 1, the biasing means comprises a contact portion capable of contacting the portion to be urged of the developer supply container with faces first side . In addition, the developer supply container is disposed on the side perpendicular to the straight line connecting the first side and the second side with respect to the driving roller in a state of being mounted on the mounting portion, and the biased portion is And a contacted surface that is in contact with the contact portion of the urging means and is orthogonal to the straight line.

In this apparatus, when the developer supply container is attached to the developing unit, it is not only positioned on the second side but also displaced in a direction perpendicular to the straight line between the first side and the driving roller. Is done. Therefore, if the developer container is simply biased to the second side, the biasing force may not work properly. Even when the agent supply container is displaced and disposed as described above, it is surely biased toward the first side.

According to a third aspect of the present invention , in the image forming apparatus according to the first or second aspect , the developing unit is mounted at both ends in the axial direction of the developing roller and holds a gap between the developing roller and the photosensitive drum. It further has a holding member.

In conventional developing units, holding members for maintaining a constant distance from the photosensitive drum are usually provided at both ends in the axial direction of the developing roller, but the developing roller tends to be separated from the photosensitive drum. I can't suppress that.

However in the apparatus of claim 3, even in such a case, by directly developer supply container through the opening is energized, the developer supply container, not only between the drive roller, the photosensitive drum, a developing roller The separation between them is also suppressed.

In this developing unit, the developer supply container mounted on the mounting portion is directly urged to the first side by the urging means, so that not only between the photosensitive drum and the development roller, but also the developer supply container and the drive roller The separation between them is also suppressed.

According to the image forming apparatus of the present invention, the developer supply container is directly urged to the first side by the urging unit, so that not only between the photosensitive drum and the developing roller but also the developer supply container, the drive Separation between the rollers can be suppressed. Since the biasing means has an existing configuration in this type of conventional developing unit, there is no need to provide a special member, which is advantageous in terms of cost.

According to the developing unit of the present invention, the developer supply container mounted on the mounting portion is directly urged to the first side by the urging means, so that not only between the photosensitive drum and the developing roller but also the developer supply. Separation between the container and the driving roller is also suppressed.

<Printer configuration>
FIG. 1 shows a printer 1 in which an embodiment of the present invention is employed. 2 to 6 show predetermined portions of the printer 1. In FIG. 1, the arrow indicates the sheet conveyance direction.

The printer 1 includes a printer body 3, a developing unit 5, and a toner container 7.

<Printer body>
The printer main body 3 includes a paper feed mechanism 11, an image forming unit 13, a unit mounting unit 14, a fixing unit 15, a discharge mechanism 17, and a control unit and a communication unit (not shown).

The paper feed mechanism 11 feeds the paper stored in the paper feed cassette 10 one by one, and the image forming unit 1
3 has a transport roller and a drive unit at appropriate locations on the paper feed transport path 9.

The image forming unit 13 is for forming an image on the paper conveyed through the paper feed conveyance path 9. The image forming unit 13 includes a photosensitive drum 21, a charger 23 disposed around the photosensitive drum 21, an exposure unit 25, and a transfer unit. A roller 27 and a cleaning mechanism 29 are provided.

The photosensitive drum 21 is a cylindrical rotating body having a toner image formed on the surface thereof, and is driven to rotate by a driving unit (not shown) along with a printing operation. The charger 23 is for charging the surface of the photosensitive drum 21. The exposure device 25 is for forming an electrostatic latent image on the surface of the photosensitive drum 21 based on image data sent from the control unit. The transfer roller 27 is
This is for transferring a toner image formed on the surface of the photosensitive drum 21 onto a sheet. The cleaning mechanism 29 is for collecting the toner remaining on the surface of the photosensitive drum 21 after the toner image is transferred.

The unit mounting portion 14 is for detachably mounting the developing unit 5, and guide members and locking means (not shown) are arranged at appropriate positions. The unit mounting portion 14
Is an urging means 4 for urging the developing unit 5 forward (first side, left in FIG. 1).
3.

The urging means 43 is an opening 33c (described later) provided in the casing 33 of the developing unit 5.
This is for directly energizing the toner container 7 via. The urging means 43 includes a coil spring 43a that is arranged to be extendable in the front-rear direction, and a contact member 43b (contact portion) that is attached to the front end of the coil spring 43a. The abutting member 43 b can abut against a contacted portion 57 (described later) of the toner container 7.

The fixing unit 15 is for fusing and fixing the toner image to the sheet on which the toner image has been transferred in the image forming unit 13, and includes a heating roller having a built-in heater and a pressurization disposed opposite thereto. It has a roller.

The discharge mechanism 17 is for discharging the paper that has passed through the fixing unit 15 to the paper discharge unit 16 on the upper surface of the printer 1. The discharge mechanism 17 includes a conveyance roller and a drive unit at appropriate positions on the discharge conveyance path 12. Yes.

The control unit is for controlling the input / output units such as the image forming unit 13 and the fixing unit 15 and performing image processing on the image data received by the communication unit, and is configured by a microcomputer including a CPU and a memory. The The memory stores various program data to be executed by the CPU, and stores image data and the like.

The communication unit is for performing communication with an externally connected device such as a personal computer connected to the outside through a communication cable such as a network, and performs reception of a print job, notification of completion of printing, and the like.

<Development unit>
The developing unit 5 is for developing the photosensitive drum 21 and is detachably attached to the printer main body 3. The developing unit 5 includes a developing roller 31 and a holding member 32.
A casing 33, conveying members 35 and 36, a driving roller 37, and a fixed lever 41.

The developing roller 31 is for supplying toner to the photosensitive drum 21 and is rotatably held at the front end of the casing 33. In a mounted state with respect to the printer main body 3, it is disposed adjacent to the photosensitive drum 21. The developing roller 31 is drivingly connected to a driving portion of the photosensitive drum 21 via a gear (not shown).

The holding member 32 is a member for keeping the gap between the developing roller 31 and the photosensitive drum 21 constant, and is attached to both end portions of the developing roller 31 in the axial direction.

The casing 33 has a space for holding the developing roller 31, the driving roller 37, and the like and sending the toner replenished from the toner container 7 to the front side. Further, the casing 33 has a roller holding portion 3 for holding the driving roller 37 at the end portion on the front side.
3a, and a container mounting portion 33b for detachably mounting the toner container 7 at an end portion on the rear side (second side, right side in FIG. 1). Furthermore, the container mounting part 3
On the lower side of 3b (the side perpendicular to the straight line connecting the front side and the rear side, the upper side in FIG. 1) and the front side, a driving roller 37 is rotatably arranged. Moreover, the opening part 33c is provided in the axial direction one end part of the edge part of the back side of the container mounting part 33b.

The conveying members 35 and 36 are for feeding the toner from the toner container 7 to the front side while stirring, and are rotatable in parallel with each other between the roller holding portion 33a and the container mounting portion 33b in the casing 33. Is arranged.

The driving roller 37 is for driving a paddle member 53 (described later) of the toner container 7 and is drivingly connected to a driving gear 54 (described later). The drive roller 37 is rotationally driven in the direction of arrow B in FIG. 2, and the drive gear 54 is rotationally driven in the direction of arrow A.

The fixing lever 41 is a member for fixing the toner container 7 mounted on the container mounting portion 33b to the container mounting portion 33b. The toner container 7 is connected to the container mounting portion 33b.
The slider slides in the axial direction along with the operation of being attached to b, and is engaged with the front end of the toner container 7.

<Toner container>
The toner container 7 is a container for supplying toner filled therein to the developing unit 5 and is detachably mounted on the container mounting portion 33 b of the developing unit 5. The toner container 7 includes a paddle member 53 (stirring member) and a driving gear 54, a toner conveying member 55 and a driving gear 56, and a contacted portion 57 (biased portion).

The paddle member 53 is an agitating member for agitating the toner, and is arranged extending in the longitudinal direction of the toner container 7.

The drive gear 54 is a gear that rotates integrally with the paddle member 53 and is drivingly connected to the drive roller 37.

The toner conveying member 55 collects toner at a supply port (not shown) provided on the bottom surface of the toner container 7 and drops the toner into the casing 33.

The drive gear 56 is a gear that rotates integrally with the toner conveying member 55, and is engaged with the drive gear 54 of the paddle member 53.

The abutted portion 57 (biased portion) is a protrusion that receives the urging force toward the front side by the urging means 43 and is formed at an end portion on the rear side. The contacted portion 57 has a contacted surface 57a that extends in the vertical direction and is in contact with the contact member 43b of the biasing means 43.

<Printer operation>
Next, the operation of the printer 1 will be described.

In order to use the printer 1, first, the toner container 7 is mounted on the container mounting portion 33 b of the developing unit 5. At this time, the toner container 7 is fixed to the developing unit 5 by the fixing lever 41, and the driving gear 54 is drivingly connected to the driving roller 37.

Next, the developing unit 5 in which the toner container 7 is mounted is mounted on the unit mounting portion 14 of the printer main body 3 so as to move forward.

When the developing unit 5 is attached to the printer main body 3 in this way, the contact member 43b of the biasing means 43 contacts the contacted portion 57 of the toner container 7 through the opening 33c, and the coil spring 43a expands and contracts. It becomes a state. As a result, a forward pressing force acts on the toner container 7, and a forward pressing force also acts on the casing 33 via the container mounting portion 33b. Accordingly, the drive roller 37 holds the state of approaching the photosensitive drum 21 via the holding member 32 while maintaining a certain gap.

In this way, when the printer 1 is ready for use and accepts a print job from an externally connected device, the sheets are fed one by one from the sheet feeding cassette 10, and the sheets pass through the sheet feeding conveyance path 9 to form an image. It is conveyed to the forming unit 13. Here, the photosensitive drum 21 is rotationally driven by a driving unit, and after the surface is charged, the photosensitive drum 21 is exposed to form an electrostatic latent image, and then the developing roller 31.
Then, the toner is supplied to form a toner image, and the transfer roller 27 transfers the toner image onto the paper.

Then, the sheet is further conveyed downstream, and the toner image is melted and fixed by passing through the fixing unit 15. Thereafter, the paper is discharged to the paper discharge unit 16 through the discharge conveyance path 12, and the printing operation is completed.

In this series of printing operations, the developing roller 31 receives a driving force from the driving unit of the photosensitive drum 21 and receives a force in a direction away from the photosensitive drum 21, but the driving roller 37 receives a force from the biasing unit 43. Therefore, the separation from the photosensitive drum 21 is suppressed.

On the other hand, in the developing unit 5, the driving roller 37 is rotationally driven in accordance with the printing operation, whereby the paddle member 53 is rotated through the driving gear 54, the toner is stirred, and the toner is further supplied through the driving gear 56. The conveyance member 55 rotates and the toner is supplied into the developing unit 5 through the supply port.

At this time, the driving gear 54 receives the driving force from the driving roller 37 and tries to move away from the driving roller 37, but since the forward pressure is acting on the toner container 7, The separation is suppressed.

According to the above printer 1, the toner container 7 is directly urged forward by the urging means 43, so that the photosensitive drum 21, the developing roller 31, the drive gear 54, and the drive roller 3 are urged.
The separation between the gears 7 can be suppressed, and gear skipping at the drive connecting portion can be prevented.

In this case, the use of the biasing means that is an existing configuration in this type of conventional developing unit is advantageous in terms of cost without using a special member.

<Other embodiments>
(A) The mode of driving connection between the photosensitive drum and the developing roller, and between the developer supply container and the driving roller is not particularly limited to that described in the above embodiment.

(B) The image forming apparatus includes an image forming apparatus in which the developer supply container is not attached to the developing unit.

(C) The image forming apparatus may be not only a printer but also a copier, a facsimile machine, or a multifunction machine having both functions.

1 is a longitudinal sectional view showing a printer in which an embodiment of the present invention is adopted. FIG. 2 is a longitudinal sectional view showing a main part of the printer at a plurality of cut surfaces. FIG. 2 is a perspective view showing a predetermined portion of a printer main body of the printer. FIG. 3 is a perspective view showing a predetermined portion of the developing unit of the printer. FIG. 3 is a perspective view showing a predetermined portion of the developing unit in a state where a developer supply container is mounted. The perspective view which shows a predetermined part in the state which abbreviate | omitted the upper surface part of the said developer supply container.

Explanation of symbols

1 Printer 3 Printer body (image forming apparatus body)
5 Development unit 7 Toner container (developer supply container)
21 Photosensitive drum 31 Developing roller 32 Holding member (holding means)
33a Holding portion 33b Container mounting portion (mounting portion)
33c opening 37 drive roller 43 urging means 43b contact member 53 paddle member (stirring member)
57 Contacted part (biased part)
57a Contacted surface

Claims (3)

An image forming apparatus main body having a photosensitive drum;
A developing roller that is detachably attached to the image forming apparatus main body and can be disposed adjacent to the photosensitive drum and is driven to rotate as the photosensitive drum rotates, and the photosensitive drum side The developing unit having a holding portion for holding the developing roller at an end portion on the first side,
A developer replenishing container that is filled with a developer, has a stirring member for stirring the developer, and a drive gear that rotates integrally with the stirring member, and is detachably attached to the developing unit; ,
The developing unit includes a mounting portion in which the developer supply container is detachably mounted at a second side end opposite to the photosensitive drum, and an opening is provided at the second side end, and the mounting A driving roller for driving the stirring member of the developer supply container disposed adjacent to the first side with respect to the portion and mounted on the mounting portion via the driving gear ;
The image forming apparatus main body is disposed on the second side of the mounting portion and biased to bias the developer supply container mounted on the developing unit through the opening of the mounting portion to the first side. Further comprising means,
Said developer supply container is to have a portion to be urged for receiving a biasing force to the first side by said biasing means to an end portion of the second side, wherein the drive gear is drivingly connected to said drive roller ,
Image forming apparatus. The biasing means has a contact portion facing the first side and capable of contacting the biased portion of the developer supply container,
The developer replenishing container is disposed on the side perpendicular to the straight line connecting the first side and the second side with respect to the driving roller in a state of being mounted on the mounting portion, and the biased container Department
Having a contacted surface that is in contact with the contact portion of the biasing means and is orthogonal to the straight line;
The image forming apparatus according to claim 1. 3. The development unit according to claim 1, wherein the development unit further includes a holding member that is attached to both ends in the axial direction of the development roller and holds a gap between the development roller and the photosensitive drum. The image forming apparatus described.

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