JP2020140068A - Image forming apparatus - Google Patents

Abstract

To satisfactorily determine the position of a developing roller in an axial direction.SOLUTION: An image forming apparatus comprises: a developing cartridge 60 that includes a developing roller 62; a drum cartridge to which the developing cartridge 60 is removably attached and that includes first bearings (bearings 110); and an apparatus body to which the drum cartridge is removably attached. The apparatus body has a first positioning part. The first bearings each include a cylindrical support part 111 that rotatably supports one end of a photoreceptor drum, and a plate-like base part 113 that extends from an outer peripheral surface of the support part 111. The base part 113 has a guide groove G1 that guides a shaft 62A of the developing roller 62, and a contact part (contact projection T1) that has a first contact surface TF1 in contact with the first positioning part in an axial direction of the developing roller 62 in a state where the drum cartridge is attached to the apparatus body. When projected in the axial direction, a part of the first contact surface TF1 of the contact part overlaps part of the developing roller 62.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image forming apparatus including a bearing that supports a photoconductor drum.

Conventionally, as a drum cartridge, a drum frame, a bearing supported by the drum frame, and a photoconductor drum rotatably supported by the bearing are known (see Patent Document 1). In this technique, the bearing has a guide groove that guides the shaft of the developing roller.

Japanese Unexamined Patent Publication No. 2012-118176

By the way, it is conceivable to position the developing roller in the axial direction by urging the developing roller in the axial direction with a spring or the like and pressing the developing roller against a portion around the guide groove of the bearing. However, in such a configuration, the portion around the guide groove of the bearing may be deformed, and the developing roller may not be well positioned in the axial direction.

Therefore, an object of the present invention is to position the developing roller satisfactorily in the axial direction.

In order to solve the above problems, the image forming apparatus according to the present invention is a developing cartridge including a developing roller including a shaft and a drum cartridge to which the developing cartridge can be attached and detached, and is a photoconductor drum and one end of the photoconductor drum. It includes a first bearing that rotatably supports the portion, a drum cartridge having a frame that supports the first bearing, and a device body to which the drum cartridge with the developing cartridge attached can be attached and detached.
The apparatus main body has a first positioning unit.
The first bearing includes a cylindrical support portion that rotatably supports one end portion of the photoconductor drum, and a plate-shaped base portion that extends from the outer peripheral surface of the support portion.
The base portion has a guide groove for guiding the shaft of the developing roller, and the drum cartridge with the developing cartridge mounted on the apparatus main body, and the developing is provided on the first positioning portion. It has a contact portion having a first contact surface that contacts in the axial direction of the roller.
A part of the first contact surface of the contact portion overlaps with a part of the developing roller when projected in the axial direction.

According to this configuration, when the drum cartridge with the developing cartridge mounted is mounted on the apparatus main body, the first contact surface of the contact portion having a portion overlapping a part of the developing roller projected in the axial direction is the apparatus. Axial contact with the first positioning portion of the main body. As a result, it is possible to prevent the plate-shaped base portion from being deformed in the axial direction, so that the developing roller can be well positioned in the axial direction.

Further, the apparatus main body has a second positioning portion, and the first bearing is attached to the second positioning portion when the drum cartridge with the development cartridge attached is attached to the apparatus main body. , May have a second contact surface that contacts in the axial direction.

Further, the first contact surface may be located at a position farther from the center of the photoconductor drum in the axial direction than the second contact surface in the axial direction.

Further, the drum cartridge includes a drum coupling into which a driving force for driving the photoconductor drum is input, and the drum coupling is located at the other end of the photoconductor drum in the axial direction. You may.

Further, the developing cartridge includes a developing coupling into which a driving force for driving the developing roller is input, and the developing coupling may be located at the other end of the developing cartridge in the axial direction. Good.

Further, the contact portion may protrude from the base portion in the axial direction.

Further, the contact portions may be provided on both sides of the guide groove.

According to this, it is possible to further suppress the plate-shaped base portion from being deformed in the axial direction.

Further, the apparatus main body has a second positioning portion, the drum cartridge includes a second bearing that rotatably supports the other end portion of the photoconductor drum, and the second bearing is provided by the developing cartridge. When the drum cartridge in the mounted state is mounted on the apparatus main body, the second positioning portion may have a second contact surface that comes into contact with the axial direction.

Further, the drum cartridge includes a drum coupling into which a driving force for driving the photoconductor drum is input, and the drum coupling is located at one end of the photoconductor drum in the axial direction. You may.

Further, the drum cartridge may include an urging member that urges the developing cartridge toward one end side in the axial direction.

According to the present invention, the developing roller can be satisfactorily positioned in the axial direction.

It is a figure which shows the schematic structure of the color printer which concerns on one Embodiment of this invention. It is a perspective view which shows the structure of one end side in the axial direction of a drum cartridge. It is a perspective view (a) and a side view (b) which show the bearing on one end side. It is a perspective view which shows the structure of the other end side in the axial direction of a process cartridge. It is a perspective view (a) and a side view (b) which show the bearing on the other end side. It is a figure which shows the structure for locating a drum cartridge and a developing cartridge with an apparatus main body in an axial direction. It is a perspective view which shows the modification of the contact protrusion. It is a figure (a)-(c) which shows the leaf spring which urges a developing cartridge. It is a side view which shows the form which changed the position of the 1st positioning part.

Next, one embodiment of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, a color printer 1 as an example of an image forming apparatus includes an apparatus main body 10, a top cover 11, a paper feeding unit 20, and an image forming unit 30.

The top cover 11 is a cover that opens and closes the opening 10A formed in the upper part of the apparatus main body 10. The top cover 11 is arranged on the upper part of the apparatus main body 10. The top cover 11 is rotatably provided on the apparatus main body 10 about the rotation shaft 11A. The upper surface of the top cover 11 is a paper ejection tray 11B on which the ejected paper P is placed.

The paper feed unit 20 is provided in the lower part of the apparatus main body 10, and includes a paper feed tray 21 for accommodating the paper P and a paper supply mechanism 22 for supplying the paper P from the paper feed tray 21 to the image forming unit 30. There is. The paper P in the paper feed tray 21 is separated one by one by the paper supply mechanism 22 and supplied to the image forming unit 30.

The image forming unit 30 includes four exposure heads 40, four process cartridge PCs, a transfer unit 70, and a fixing unit 80.

The exposure head 40 has a plurality of LEDs. The exposure head 40 is held by the top cover 11 so as to be suspended from the top cover 11. The exposure head 40 exposes the surface of the photoconductor drum 51 by blinking a plurality of LEDs based on the image data.

Each process cartridge PC is arranged between the top cover 11 and the paper feed tray 21. Each process cartridge PC can be attached to and detached from the apparatus main body 10 through the opening 10A in a state where the top cover 11 is opened. The process cartridge PC includes a drum cartridge 50 and a developing cartridge 60 that can be attached to and detached from the drum cartridge 50.

The drum cartridge 50 includes a cylindrical photoconductor drum 51, a charger 52 for charging the photoconductor drum 51, a pressing spring 53 for urging the developing cartridge 60 toward the photoconductor drum 51, and a cleaning roller 54. It includes a drum frame 55 that supports the photoconductor drum 51 and the like.

The cleaning roller 54 is a roller that collects foreign matter such as toner remaining on the photoconductor drum 51. The cleaning roller 54 is in contact with the photoconductor drum 51 and can rotate. The cleaning roller 54 includes a shaft 54A and a roller portion 54B provided around the shaft 54A.

The developing cartridge 60 includes a developing housing 61 for accommodating toner and a developing roller 62 for supplying the toner in the developing housing 61 to the photoconductor drum 51. The developing roller 62 includes a shaft 62A and a roller portion 62B provided around the shaft 62A. The developing roller 62 can rotate while being urged by the photoconductor drum 51 by the pressing spring 53.

The transfer unit 70 is provided between the paper feed tray 21 and the process cartridge PC. The transfer unit 70 includes a drive roller 71, a driven roller 72, an endless transfer belt 73, and four transfer rollers 74. The drive roller 71 and the driven roller 72 support the transport belt 73.

The transport belt 73 is a belt that transports the paper P. The outer surface of the transport belt 73 is in contact with each photoconductor drum 51. Each transfer roller 74 sandwiches a transport belt 73 with each photoconductor drum 51.

The fixing unit 80 includes a heating roller 81 and a pressure roller 82. The pressure roller 82 is pressed by the heating roller 81.

In such an image forming unit 30, first, the charger 52 charges the surface of the photoconductor drum 51. After that, the exposure head 40 exposes the surface of the photoconductor drum 51. As a result, an electrostatic latent image is formed on the photoconductor drum 51.

The developing roller 62 then supplies toner to the electrostatic latent image on the photoconductor drum 51. As a result, a toner image is formed on the photoconductor drum 51.

When the paper P passes between the transport belt 73 and the photoconductor drum 51, the toner image on the photoconductor drum 51 is transferred onto the paper P. After that, the toner image on the paper P is fixed by the fixing unit 80. Next, the paper P is discharged to the paper discharge tray 11B by the discharge roller 91.

Next, the structure of the drum cartridge 50 and the structure of the apparatus main body 10 around the drum cartridge 50 will be described in detail. In the following description, the axial direction of the photoconductor drum 51 and the developing roller 62 is simply referred to as “axial direction”.

As shown in FIG. 2, the drum cartridge 50 includes a bearing 110 as an example of the first bearing at one end in the axial direction. The bearing 110 is a member for rotatably supporting one end of the photoconductor drum 51. The bearing 110 is supported by the drum frame 55.

The bearing 110 has two contact protrusions T1 and a second contact surface TF2 as an example of the contact portion. On the other hand, the apparatus main body 10 has two first positioning portions PP1 and a second positioning portion PP2. Each contact projection T1 has a first contact surface TF1 at its tip.

The first contact surface TF1 is a surface that contacts the first positioning portion PP1 in the axial direction when the process cartridge PC (drum cartridge 50 with the developing cartridge 60 mounted) is mounted on the apparatus main body 10. .. The second contact surface TF2 is a surface that contacts the second positioning portion PP2 in the axial direction when the process cartridge PC is mounted on the apparatus main body 10. As shown in FIG. 6, the first contact surface TF1 is located at a position farther from the central CL in the axial direction of the photoconductor drum 51 than the second contact surface TF2 in the axial direction.

As shown in FIGS. 3A and 3B, the bearing 110 on one end side is located at the cylindrical support portion 111, the wall 112 located at one end of the support portion 111, and the other end of the support portion 111. It has a base portion 113. The support portion 111 is a portion that rotatably supports one end of the photoconductor drum 51. The support portion 111 may directly support one end of the photoconductor drum 51, or indirectly support one end of the photoconductor drum 51 by supporting a member fixed to one end of the photoconductor drum 51. May be supported by.

The wall 112 is formed so as to cover the opening on one end side of the cylindrical support portion 111. The wall 112 has the above-mentioned second contact surface TF2. The base portion 113 is a plate-shaped portion. The base portion 113 extends from the outer peripheral surface of the support portion 111.

The base portion 113 has a guide groove G1, a head support surface F1, and the above-mentioned two contact protrusions T1.

The guide groove G1 is a groove that guides the shaft 62A of the developing roller 62. Specifically, the guide groove G1 guides the shaft 62A via the bearing portion B11 shown by the hatching of dots in FIG. 3 (b).

Here, the developing cartridge 60 includes a developing bearing B1 having a bearing portion B11. The developing bearing B1 is provided in the developing housing 61 of the developing cartridge 60. The developing bearing B1 has a bearing portion B11 and a plate-shaped base portion B12.

The bearing portion B11 is a portion that rotatably supports the shaft 62A. The base portion B12 extends from the outer peripheral surface of the bearing portion B11. The base portion B12 has a contact surface B13 that contacts the base portion 113 of the bearing 110. The contact surface B13 is formed so as to surround the bearing portion B11. The contact surface B13 comes into contact with the portion of the base portion 113 around the guide groove G1.

The head support surface F1 is a surface that comes into contact with the exposure head 40. When the exposure head 40 comes into contact with the head support surface F1, the distance between the exposure head 40 and the photoconductor drum 51 can be maintained at a constant distance.

The contact projection T1 projects axially from the base portion 113. The two contact protrusions T1 are provided on both sides of the guide groove G1. Then, a part of the first contact surface TF1 of the contact projection T1 overlaps with a part of the developing roller 62 when projected in the axial direction.

As shown in FIG. 4, the drum cartridge 50 includes a bearing 120 at the other end in the axial direction. The bearing 120 is a member for rotatably supporting the other end of the photoconductor drum 51. The bearing 120 is supported by the drum frame 55.

A drum coupling CP1 is provided at the other end of the photoconductor drum 51 in the axial direction. The drum coupling CP1 is a member to which a driving force for driving the photoconductor drum 51 is input from the first driving force output member 210 (see FIG. 6) described later.

A development coupling CP2 is provided at the other end of the development cartridge 60 in the axial direction. The development coupling CP2 is a member to which a driving force for driving the developing roller 62 is input from the second driving force output member 310 (see FIG. 6) described later.

As shown in FIGS. 5A and 5B, the bearing 120 on the other end side has a cylindrical support portion 121 and a base portion 123. The support portion 121 is a portion that rotatably supports the other end of the photoconductor drum 51. Specifically, the support portion 121 indirectly supports the other end of the photoconductor drum 51 by supporting the drum coupling CP1 (see FIG. 4) fixed to the other end of the photoconductor drum 51. There is.

The base portion 123 is a plate-shaped portion. The base portion 123 extends from the outer peripheral surface of the support portion 121.

The base portion 123 has a guide groove G2, a head support surface F2, and a protrusion T2.

The guide groove G2 is a groove that guides the shaft 62A of the developing roller 62. Specifically, the guide groove G2 guides the shaft 62A via the bearing B2 shown by the hatching of dots in the figure. Here, the bearing B2 is a member that rotatably supports the shaft 62A. The bearing B2 is provided in the developing housing 61 of the developing cartridge 60 described above.

The head support surface F2 is a surface that comes into contact with the exposure head 40. When the exposure head 40 comes into contact with the head support surface F2, it is possible to maintain the distance between the exposure head 40 and the photoconductor drum 51 at a constant distance.

The protrusion T2 protrudes axially from the base portion 123. The protrusion T2 is arranged around the guide groove G1. Specifically, a part of the tip surface T21 of the protrusion T2 overlaps with a part of the developing roller 62 when projected in the axial direction. In this embodiment, the protrusion T2 does not function in particular, and may not be provided.

As shown in FIG. 6, the apparatus main body 10 further includes a first driving force output member 210, a first driving force transmitting member 220, a second driving force output member 310, and a second driving force transmitting member 320. ing.

The first driving force transmitting member 220 is rotatably supported by the apparatus main body 10. The first driving force transmitting member 220 has a gear portion 221 to which a driving force from a motor (not shown) provided in the apparatus main body 10 is input, and a protruding portion 222 protruding from the gear portion 221 in the axial direction. ..

The first driving force output member 210 is a member that outputs a driving force to the drum coupling CP1. The first driving force output member 210 is supported by a protruding portion 222 of the first driving force transmitting member 220 so as to be able to advance and retreat in the axial direction. The first driving force output member 210 is engaged with the protrusion 222 in the rotation direction of the photoconductor drum 51.

A plurality of protrusions 211 for transmitting the driving force to the drum coupling CP1 are provided at the end of the first driving force output member 210 on the drum cartridge 50 side. A spring (not shown) is provided between the first driving force output member 210 and the first driving force transmitting member 220.

The first driving force output member 210 is movable between a connection position connected to the drum coupling CP1 and a retracted position retracted from the drum coupling CP1. The first driving force output member 210 is pressed from the connection position toward the retracted position by a cam (not shown), so that the first driving force output member 210 moves from the connection position to the retracted position against the urging force of the spring. Further, the first driving force output member 210 moves from the retracted position to the contact position by the urging force of the spring when the cam is released while the first driving force output member 210 is located at the retracted position.

The second driving force output member 310 is a member that outputs a driving force to the developing coupling CP2. The second driving force output member 310 is movable between a connection position connected to the development coupling CP2 and a retracted position retracted from the development coupling CP2. Since the second driving force output member 310 and the second driving force transmitting member 320 have substantially the same structure as the first driving force output member 210 and the first driving force transmitting member 220 described above, detailed description thereof will be omitted. To do.

When the first driving force output member 210 moves from the retracted position to the connection position while the process cartridge PC is mounted on the apparatus main body 10, the drum cartridge 50 is moved by the first driving force output member 210 to the second positioning portion PP2. Is pressed toward. Then, when the second contact surface TF2 of the drum cartridge 50 comes into contact with the second positioning portion PP2, the drum cartridge 50 is positioned in the axial direction.

When the second driving force output member 310 moves from the retracted position to the connection position while the process cartridge PC is mounted on the apparatus main body 10, the developing cartridge 60 is moved to one side in the axial direction by the second driving force output member 310. Is pressed against. As a result, as shown in FIG. 3A, the contact surface B13 of the developing bearing B1 on one end side of the developing cartridge 60 comes into contact with the base portion 113 of the bearing 110 of the drum cartridge 50.

When the contact surface B13 of the developing bearing B1 comes into contact with the base portion 113 in this way, a force is applied to the base portion 113, and the base portion 113 tends to bend to one side in the axial direction. However, as shown in FIG. 6, the first contact surface TF1 at the tip of the contact projection T1 projecting from the base portion 113 in the axial direction comes into contact with the first positioning portion PP1 of the apparatus main body 10, whereby the base portion 113 Since the deflection of the developing cartridge 60 is restricted, the developing cartridge 60 can be well positioned in the axial direction.

Based on the above, the following effects can be obtained in the present embodiment.
Since it is possible to prevent the plate-shaped base portion 113 from being deformed in the axial direction, the developing roller 62 can be satisfactorily positioned in the axial direction.

Since the contact protrusions T1 are provided on both sides of the guide groove G1, it is possible to further suppress the plate-shaped base portion 113 from being deformed in the axial direction.

The present invention is not limited to the above embodiment, and can be used in various forms as illustrated below. In the following description, members having substantially the same structure as that of the above embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 7, the bearing 110 may further have a connecting portion R1 that connects the tips of the two contact projections T1 to each other. Then, the connecting portion R1 may have a first contact surface R11 that contacts the first positioning portion PP1 of the apparatus main body 10. According to this form, the number of the first positioning portions PP1 provided in the apparatus main body 10 can be set to, for example, one.

As shown in FIG. 8A, a leaf spring SP1 as an example of the urging member may be provided on one end side of the drum cartridge 50. The leaf spring SP1 is a member for urging the developing cartridge 60 toward the other end side in the axial direction. The urging member is not limited to the leaf spring SP1, and may be, for example, a wire spring, a coil spring, a torsion spring, or the like.

As shown in FIGS. 8 (b) and 8 (c), the leaf spring SP1 has a fixed portion SP11 fixed to the drum frame 55 and an urging portion SP12 bent from the fixed portion SP11. The urging portion SP12 is a portion for urging the developing cartridge 60 toward the other end side in the axial direction in contact with the developing cartridge 60.

The leaf spring SP1 can be a spring that generates an urging force larger than the urging force of the spring that urges the second driving force transmitting member 320 described above. In this case, the developing cartridge 60 is urged to the other end side in the axial direction with respect to the drum cartridge 50, contrary to the above embodiment.

Therefore, in this case, as shown in FIG. 9, the first positioning portion PP1 is arranged on the other end side in the axial direction, and is arranged with the tip surface T21 of the protrusion T2 of the bearing 120 on the other end side in the axial direction. You just have to make contact. In this form, the bearing 120 corresponds to the first bearing, and the bearing 110 corresponds to the second bearing. That is, in this embodiment, it corresponds to an example in which one end and the other end in the axial direction of the embodiment are viewed in reverse. Specifically, in the above embodiment, the right side shown in FIG. 6 is one end in the axial direction and the left side shown is the other end in the axial direction. However, in this embodiment, the left side shown in FIG. 9 is one end in the axial direction. The right side is the other end in the axial direction.

Therefore, in this embodiment, the bearing 120 and the drum coupling CP1 arranged at the other end in the axial direction in the embodiment are arranged at one end in the axial direction, and are arranged at one end in the axial direction in the embodiment. The bearing 110 is arranged at the other end in the axial direction. Further, in this form, the leaf spring SP1 urges the developing cartridge 60 toward one end side in the axial direction. Therefore, in this form, the protrusion T2 corresponds to the contact portion, and the tip surface T21 corresponds to the first contact surface.

In the above embodiment, the first contact surface TF1 is arranged at a position farther from the central CL in the axial direction of the photoconductor drum 51 than the second contact surface TF2 in the axial direction, but the present invention is limited thereto. is not. For example, the first contact surface and the second contact surface may be arranged at the same position in the axial direction, or the second contact surface may be located farther from the center of the photoconductor drum in the axial direction than the first contact surface. It may be arranged.

In the above embodiment, the present invention is applied to the color printer 1, but the present invention is not limited to this, and the present invention may be applied to other image forming devices such as monochrome printers, copiers, and multifunction devices. Good.

Each element described in the above-described embodiment and modification may be arbitrarily combined and implemented.

1 Color printer 10 Device body 50 Drum cartridge 51 Photoreceptor drum 55 Drum frame 60 Development cartridge 62 Development roller 62A Shaft 110 Bearing 111 Support part 113 Base part G1 Guide groove PP1 First positioning part T1 Contact protrusion TF1 First contact surface

Claims (11)

A developing cartridge with a developing roller including a shaft,
A drum cartridge to which the developing cartridge is removable, which includes a photoconductor drum, a first bearing that rotatably supports one end of the photoconductor drum, and a frame that supports the first bearing.
An image forming apparatus including a device main body to which the drum cartridge can be attached and detached with the developing cartridge attached.
The apparatus main body has a first positioning unit and has a first positioning unit.
The first bearing is
A cylindrical support portion that rotatably supports one end portion of the photoconductor drum, and a cylindrical support portion.
A plate-shaped base portion extending from the outer peripheral surface of the support portion is provided.
The base portion
A guide groove for guiding the shaft of the developing roller and
In a state where the drum cartridge with the developing cartridge mounted is mounted on the apparatus main body, the first positioning portion has a contact portion having a first contact surface that contacts the developing roller in the axial direction. Have and
An image forming apparatus characterized in that a part of the first contact surface of the contact portion overlaps with a part of the developing roller when projected in the axial direction. The device body has a second positioning unit and has a second positioning unit.
The first bearing has a second contact surface that contacts the second positioning portion in the axial direction when the drum cartridge with the development cartridge mounted is mounted on the apparatus main body. The image forming apparatus according to claim 1. The image forming apparatus according to claim 2, wherein the first contact surface is located at a position farther from the center of the photoconductor drum in the axial direction than the second contact surface in the axial direction. The drum cartridge includes a drum coupling into which a driving force for driving the photoconductor drum is input.
The image forming apparatus according to claim 2 or 3, wherein the drum coupling is located at the other end of the photoconductor drum in the axial direction. The developing cartridge includes a developing coupling into which a driving force for driving the developing roller is input.
The image forming apparatus according to any one of claims 1 to 4, wherein the development coupling is located at the other end of the development cartridge in the axial direction. The image forming apparatus according to any one of claims 1 to 5, wherein the contact portion protrudes from the base portion in the axial direction. The image forming apparatus according to claim 6, wherein the contact portions are provided on both sides of the guide groove. The first bearing has two protrusions protruding in the axial direction from the base portion.
The image forming apparatus according to any one of claims 1 to 5, wherein the contact portion connects the tips of the two protrusions to each other. The device body has a second positioning unit and has a second positioning unit.
The drum cartridge includes a second bearing that rotatably supports the other end of the photoconductor drum.
The second bearing has a second contact surface that contacts the second positioning portion in the axial direction when the drum cartridge with the development cartridge mounted is mounted on the apparatus main body. The image forming apparatus according to claim 1. The drum cartridge includes a drum coupling into which a driving force for driving the photoconductor drum is input.
The image forming apparatus according to claim 9, wherein the drum coupling is located at one end of the photoconductor drum in the axial direction. The image forming apparatus according to claim 9, wherein the drum cartridge includes an urging member that urges the developing cartridge toward one end side in the axial direction.

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