JP7690746B2 - Drum Cartridge - Google Patents

Description

This disclosure relates to a drum cartridge equipped with a cleaning roller for cleaning a photosensitive drum.

Conventionally, a drum cartridge is known that includes a photosensitive drum, a cleaning roller, a pressing member, and a cleaning electrode (see Patent Document 1). The photosensitive drum is rotatable about a drum axis that extends in a first direction. The cleaning roller has a cleaning shaft that extends in the first direction.

The pressing member presses the cleaning roller against the photosensitive drum in a second direction perpendicular to the first direction, and is in contact with the outer circumferential surface of the cleaning shaft. The cleaning electrode is in contact with one end of the cleaning shaft in the first direction.

The drum cartridge is detachably attached to the main body housing. The main body housing has a main body electrode for supplying electricity to the cleaning electrode. The main body electrode has a contact portion that contacts the cleaning electrode and a spring portion that biases the contact portion in a first direction toward the cleaning electrode.

JP 2014-106349 A

However, in the conventional technology, the pressing member comes into contact with the outer circumferential surface of the cleaning shaft, causing friction between the cleaning shaft and the pressing member. Furthermore, when the drum cartridge is attached to the main body housing, the cleaning electrode is pressed against one end of the cleaning shaft in the first direction by the biasing force of the main body electrode, causing friction between the cleaning shaft and the cleaning electrode.
This increases the frictional force acting on the cleaning shaft, which may make it difficult for the cleaning roller to rotate.

The present disclosure therefore aims to prevent the frictional force acting on the cleaning shaft from increasing and making it difficult for the cleaning roller to rotate when a drum cartridge includes a photosensitive drum, a cleaning roller, a pressing member, and a cleaning electrode.

In order to solve the above-mentioned problems, the drum cartridge of the present disclosure includes a photosensitive drum rotatable about a drum axis extending in a first direction, a cleaning roller in contact with the photosensitive drum, the cleaning roller having a cleaning shaft, a pressing member that presses the cleaning roller against the photosensitive drum, the pressing member contacting an outer peripheral surface of the cleaning shaft, and a cleaning electrode electrically connected to the cleaning roller.
The cleaning electrode is electrically connected to the cleaning roller via the pressing member.

According to this configuration, the cleaning electrode is electrically connected to the cleaning shaft using a pressing member for pressing the cleaning roller against the photosensitive drum, so there is no need to press the cleaning electrode against one end of the cleaning shaft. In other words, compared to conventional structures, friction between the cleaning electrode and the cleaning shaft can be eliminated, so that in a drum cartridge equipped with a photosensitive drum, a cleaning roller, a pressing member, and a cleaning electrode, the frictional force acting on the cleaning shaft can be prevented from increasing, and the cleaning roller can be prevented from becoming difficult to rotate. In addition, the structure can be simplified compared to a structure in which the cleaning electrode is electrically connected to the cleaning shaft via a member other than the pressing member, for example.

The cleaning roller may be rotatable about a cleaning axis extending in the first direction, and the pressing member may press the cleaning roller against the photosensitive drum in a second direction intersecting the first direction.

The second direction may also be perpendicular to the first direction.

The cleaning electrode may also be spaced apart from the cleaning shaft in the second direction.

The cleaning shaft may also be located between the photosensitive drum and the pressing member in the second direction.

The device may also include a connection spring that electrically connects the pressing member and the cleaning electrode.

With this configuration, the connecting spring can more reliably establish an electrical connection between the pressing member and the cleaning electrode.

The connection spring may also be located between the pressing member and the cleaning electrode in the first direction.

The connecting spring may also be a coil spring that is expandable and contractible in the first direction.

The cleaning electrode may also have a first boss extending in the first direction and fitting into one end of the connection spring in the first direction.

With this configuration, the first boss can prevent the connecting spring from coming off the cleaning electrode.

The pressing member may also have a second boss extending in the first direction and fitting into the other end of the connecting spring in the first direction.

With this configuration, the second boss can prevent the connecting spring from coming off the pressing member.

The drum cartridge may also include a drum frame that rotatably holds the photosensitive drum, and the drum frame may include a restricting boss that restricts the pressing member from moving in the first direction.

With this configuration, the restricting boss can prevent the pressing member from shifting in the first direction.

The pressing member may also have a contact portion that contacts the cleaning shaft and a first wall that extends from the contact portion toward the opposite side of the cleaning shaft and is located between the regulating boss and the connecting spring.

With this configuration, the restricting boss can restrict the pressing member from moving in the first direction due to the biasing force of the connecting spring.

The pressing member may also have a second wall extending from the contact portion toward the opposite side to the cleaning shaft, and the regulating boss may be located between the first wall and the second wall in the first direction.

With this configuration, the restricting boss can restrict the pressing member from moving in one direction or the other in the first direction.

The device may also include a spring that biases the pressing member toward the cleaning shaft, and the regulating boss may hold the spring.

This configuration simplifies the structure compared to a structure that holds the spring in a location separate from the regulating boss.

The spring may be a torsion spring having a coil portion and two arms, and the restricting boss may be a boss that fits into the coil portion.

The drum cartridge may be detachably attached to a main body housing having a main body electrode, and the cleaning electrode may be in contact with the main body electrode when the drum cartridge is attached to the main body housing.

The cleaning electrode may also have a contact surface that contacts the main body electrode when the drum cartridge is attached to the main body housing, and a guide surface that guides the main body electrode to the contact surface during the process of attaching the drum cartridge to the main body housing.

With this configuration, the guide surface guides the main body electrode to the contact surface, allowing for more reliable contact between the contact surface and the main body electrode.

The cleaning electrode may also be made of a conductive resin.

The pressing member may also be made of conductive resin.

According to the present disclosure, when a drum cartridge includes a photosensitive drum, a cleaning roller, a pressing member, and a cleaning electrode, it is possible to prevent the frictional force acting on the cleaning shaft from increasing, causing the cleaning roller to become difficult to rotate.

1 is a cross-sectional view showing a color printer including a drum cartridge according to an embodiment of the present disclosure. FIG. 2 is a perspective view showing a structure around a cleaning electrode. FIG. 2 is an exploded perspective view showing the structure around the cleaning electrode. FIG. 4 is a cross-sectional view showing a structure around a pressing member. 4A to 4C are diagrams showing the relationship between the cleaning electrode and the main body electrode.

Hereinafter, one embodiment of the present disclosure will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the color printer 1 includes a main body housing 10, a sheet supply section 20, an image forming section 30, and a discharge section 90.

The main body housing 10 has an opening 10A and an upper cover 11. The opening 10A is an opening through which a process cartridge 40 (described later) can pass. The upper cover 11 is a cover for opening and closing the opening 10A. The top surface of the upper cover 11 is an ejection tray 11A for accumulating sheets S ejected from the main body housing 10. The upper cover 11 has a number of LED mounting members 11B that hold the LED units 31.

The sheet supply unit 20 includes a supply tray 21 and a sheet transport mechanism 22. The supply tray 21 stores the sheets S. The sheet transport mechanism 22 transports the sheets S from the supply tray 21 toward the photoconductor drum 51.

The image forming unit 30 includes four LED units 31, four process cartridges 40, a transfer unit 70, and a fixing device 80.

The LED unit 31 has multiple LEDs (not shown) that expose the photoconductor drum 51. The LED unit 31 is rotatably connected to the LED mounting member 11B.

The process cartridges 40 are arranged side by side in the front-rear direction between the upper cover 11 and the sheet supply unit 20. The process cartridges 40 include a drum cartridge 50 and a developing cartridge 60. The drum cartridge 50 is detachable from the main body housing 10. The drum cartridge 50 includes a photosensitive drum 51, a charger 52, and a cleaning roller 53.

The photoconductor drum 51 is rotatable about a drum axis X1 that extends in a first direction.
The charger 52 includes a charging wire 52A for charging the photoconductor drum 51. The charging wire 52A extends in a first direction.

The cleaning roller 53 is a roller for cleaning the photosensitive drum 51. The cleaning roller 53 is in contact with the photosensitive drum 51.

The developing cartridge 60 is detachable from the drum cartridge 50. The developing cartridge 60 includes a developing roller 61, a supply roller 62, and a toner storage chamber 63.

The developing roller 61 is a roller that supplies toner to the photosensitive drum 51. The supply roller 62 is a roller that supplies toner to the developing roller 61.

The transfer unit 70 includes a drive roller 71, a driven roller 72, a conveyor belt 73, and four transfer rollers 74. The drive roller 71 and the driven roller 72 are rollers for rotating the endless conveyor belt 73. The transfer roller 74 is disposed inside the conveyor belt 73. The transfer roller 74 sandwiches the conveyor belt 73 between itself and the photosensitive drum 51.

The fixing device 80 includes a heating roller 81 and a pressure roller 82. The heating roller 81 is a roller that fixes a toner image onto the sheet S conveyed from the photosensitive drum 51. The pressure roller 82 sandwiches the sheet S between the heating roller 81 and the pressure roller 82.

In the image forming unit 30, the charger 52 charges the surface of the photoconductor drum 51. Then, the LED unit 31 exposes the surface of the photoconductor drum 51 to light. This forms an electrostatic latent image on the photoconductor drum 51.

The developing roller 61 supplies the toner in the toner storage chamber 63 to the electrostatic latent image on the photoreceptor drum 51. This forms a toner image on the photoreceptor drum 51.

The conveyor belt 73 conveys the sheet S. The sheet S passes between the photosensitive drum 51 and the transfer roller 74. At this time, the toner image on the photosensitive drum 51 is transferred to the sheet S. The sheet S then passes between the heating roller 81 and the pressure roller 82. At this time, the toner image on the sheet S is thermally fixed.

The discharge section 90 includes discharge rollers 91. The discharge rollers 91 discharge the sheet S conveyed from the fixing device 80 onto the discharge tray 11A.

As shown in FIG. 2, the cleaning roller 53 is rotatable about a cleaning axis X2 extending in the first direction. The cleaning roller 53 has a cylindrical cleaning shaft 53A and a cylindrical roller portion 53B.

The cleaning shaft 53A is made of, for example, metal. The cleaning shaft 53A is separated from the photosensitive drum 51 in a second direction that intersects with the first direction. In this embodiment, the second direction is a direction along a straight line connecting the drum axis X1 and the cleaning axis X2. Preferably, the second direction is perpendicular to the first direction. The cleaning shaft 53A is located between the photosensitive drum 51 and the pressing member 54 in the second direction.

The roller portion 53B is made of, for example, rubber. The roller portion 53B covers a portion of the cleaning shaft 53A. The roller portion 53B is in contact with the photosensitive drum 51.

The drum cartridge 50 further includes a pressing member 54, a spring 55, a cleaning electrode 56, a connecting spring 57, and a drum frame 58. The pressing member 54 and the cleaning electrode 56 are made of conductive resin. The spring 55 and the connecting spring 57 are made of, for example, metal. The drum frame 58 is made of non-conductive resin. The cleaning electrode 56 is electrically connected to the cleaning shaft 53A of the cleaning roller 53 via the connecting spring 57 and the pressing member 54.

The connection spring 57 is a spring that electrically connects the pressing member 54 and the cleaning electrode 56. The connection spring 57 is located between the pressing member 54 and the cleaning electrode 56 in the first direction. The connection spring 57 is a coil spring that can expand and contract in the first direction. One end of the connection spring 57 in the first direction contacts the cleaning electrode 56. The other end of the connection spring 57 in the first direction contacts the pressing member 54.

The cleaning electrode 56 has a first boss 56A extending in a first direction. The first boss 56A fits into one end of the connection spring 57 in the first direction. The pressing member 54 has a second boss 54D extending in the first direction. The second boss 54D fits into the other end of the connection spring 57 in the first direction.

The pressing member 54 is a member that presses the cleaning roller 53 against the photosensitive drum 51 in the second direction. The pressing members 54 are arranged at one end and the other end of the cleaning shaft 53A in the first direction. The pressing member 54 at one end presses one end of the cleaning shaft 53A in the first direction toward the photosensitive drum 51. The pressing member 54 at the other end presses the other end of the cleaning shaft 53A in the first direction toward the photosensitive drum 51. Note that the pressing member 54 at one end and the pressing member 54 at the other end have substantially the same structure, so the pressing member 54 at one end will be described below as a representative. As shown in FIG. 3, the pressing member 54 further has a contact portion 54A, a first wall 54B, and a second wall 54C.

The contact portion 54A is the portion that comes into contact with the outer circumferential surface of the cleaning shaft 53A (see also FIG. 4). The contact portion 54A has a C-shape that conforms to the outer circumferential surface of the cleaning shaft 53A.

The first wall 54B and the second wall 54C extend from the contact portion 54A in the opposite direction to the cleaning shaft 53A. The first wall 54B and the second wall 54C are spaced apart in the first direction. The second boss 54D extends in the first direction from the first wall 54B in the opposite direction to the second wall 54C.

The spring 55 is a torsion spring that biases the pressing member 54 toward the cleaning shaft 53A. The spring 55 has a coil portion 55A and two arms 55B and 55C. One arm portion 55B contacts the contact portion 54A of the pressing member 54. The other arm portion 55C contacts the base wall 58A of the drum frame 58, which will be described later.

The drum frame 58 has a base wall 58A, a side wall 58B, a protruding wall 58C, and a regulating boss 58D. The base wall 58A faces the outer peripheral surface of the photosensitive drum 51. The side wall 58B protrudes from one end of the base wall 58A in the first direction. The side wall 58B rotatably holds one end of the photosensitive drum 51 in the first direction and one end of the cleaning shaft 53A in the first direction.

The protruding wall 58C protrudes from the base wall 58A in a direction intersecting the first and second directions. The tip of the protruding wall 58C faces the cleaning electrode 56 in the first direction.

The restricting boss 58D is a boss that protrudes in a first direction from the tip of the protruding wall 58C toward the cleaning electrode 56. The restricting boss 58D holds the spring 55 by entering the coil portion 55A of the spring 55. As shown in FIG. 5, the first wall 54B of the pressing member 54 is located between the restricting boss 58D and the connecting spring 57 in the first direction. As a result, the restricting boss 58D restricts the pressing member 54, which receives force from the connecting spring 57, from moving in the first direction.

The protruding wall 58C and the restricting boss 58D are located between the first wall 54B and the second wall 54C of the pressing member 54 in the first direction. This restricts the pressing member 54 from moving in one direction and the other direction in the first direction by the protruding wall 58C and the restricting boss 58D.

The main body housing 10 has a main body electrode 12 and a main body spring 13. The main body electrode 12 is an electrode that supplies electricity to the cleaning electrode 56. As shown in FIG. 5(c), when the drum cartridge 50 is attached to the main body housing 10, the main body spring 13 biases the main body electrode 12 in a first direction toward the drum cartridge 50.

The cleaning electrode 56 is an electrode that contacts the main electrode 12 when the drum cartridge 50 is attached to the main housing 10. The cleaning electrode 56 is attached to the side wall 58B of the drum frame 58. The cleaning electrode 56 is spaced apart from the cleaning shaft 53A in the second direction. In this embodiment, the cleaning electrode 56 is spaced apart from the roller portion 53B in the second direction.

The cleaning electrode 56 has a contact surface 56B (see also FIG. 2) and a guide surface 56C. As shown in FIG. 5(c), the contact surface 56B is a surface that comes into contact with the main electrode 12 when the drum cartridge 50 is attached to the main housing 10. As shown in FIGS. 5(b) and (c), the guide surface 56C is a surface that guides the main electrode 12 to the contact surface 56B during the process of attaching the drum cartridge 50 to the main housing 10.

The contact surface 56B intersects with the first direction. Preferably, the contact surface 56B is perpendicular to the first direction. The guide surface 56C is connected to one end of the contact surface 56B in the second direction (the downstream end in the mounting direction of the drum cartridge 50). The guide surface 56C is inclined with respect to the contact surface 56B so as to approach the roller portion 53B in the first direction as it moves away from the contact surface 56B in the second direction.

Next, the process of mounting the drum cartridge 50 to the main body housing 10 and the actions of the cleaning electrode 56, main body electrode 12, and main body spring 13 when the drum cartridge 50 is mounted to the main body housing 10 will be described with reference to FIG. 5.

As shown in Figures 5(a) and (b), when the drum cartridge 50 is attached to the main body housing 10, the guide surface 56C of the cleaning electrode 56 comes into contact with the main body electrode 12. The guide surface 56C moves the main body electrode 12 in the first direction away from the drum cartridge 50 against the biasing force of the main body spring 13. As a result, as shown in Figures 5(b) and (c), the main body electrode 12 is guided to the contact surface 56B by the guide surface 56C.

As shown in FIG. 5(c), when the drum cartridge 50 is attached to the main body housing 10, the biasing force of the main body spring 13 acts on the cleaning electrode 56. However, since the cleaning electrode 56 is attached to the side wall 58B of the drum frame 58 at a position away from the cleaning roller 53 in the second direction, the biasing force of the main body spring 13 in the first direction is not applied to the cleaning roller 53.

When electricity is supplied to the cleaning roller 53 by a power source (not shown), electricity is supplied from the power source to the cleaning electrode 56 via the main spring 13 and the main electrode 12. The electricity supplied to the cleaning electrode 56 is supplied to the cleaning shaft 53A via the connecting spring 57 and the pressing member 54.

As described above, the following effects can be obtained in this embodiment.
In this embodiment, the cleaning electrode 56 is electrically connected to the cleaning shaft 53A by using a pressing member 54 for pressing the cleaning roller 53 against the photosensitive drum 51. Therefore, the cleaning electrode 56 does not come into contact with one end of the cleaning shaft 53A. As a result, it is possible to prevent the cleaning roller 53 from becoming difficult to rotate due to an increase in frictional force acting on the cleaning shaft 53A. In addition, the structure can be simplified compared to a structure in which the cleaning electrode is electrically connected to the cleaning shaft via a member other than the pressing member.

The pressing member 54 and the cleaning electrode 56 are electrically connected by the connecting spring 57, so that the electrical connection between the pressing member 54 and the cleaning electrode 56 can be more reliably achieved.

The cleaning electrode 56 has a first boss 56A that fits into one end of the connecting spring 57, preventing the connecting spring 57 from coming off the cleaning electrode 56.

The pressing member 54 has a second boss 54D that fits into the other end of the connecting spring 57, preventing the connecting spring 57 from coming off the pressing member 54.

The restricting boss 58D restricts the pressing member 54 from moving in the first direction, thereby preventing the pressing member 54 from shifting in the first direction.

The first wall 54B of the pressing member 54 is located between the restricting boss 58D and the connecting spring 57, so that the restricting boss 58D can restrict the pressing member 54 from moving in the first direction due to the biasing force of the connecting spring 57.

The restricting boss 58D is located between the first wall 54B and the second wall 54C in the first direction, so that the restricting boss 58D can restrict the pressing member 54 from moving in one direction or the other in the first direction.

The restricting boss 58D holds the spring 55, so the structure can be simplified compared to a structure in which the spring is held in a location separate from the restricting boss.

The guide surface 56C guides the main electrode 12 to the contact surface 56B, so that the contact surface 56B and the main electrode 12 can be brought into contact more reliably.

This disclosure is not limited to the above-described embodiments, but can be used in various forms, as exemplified below.

In the above embodiment, a connecting spring is interposed between the cleaning electrode and the pressing member, but the present disclosure is not limited to this, and the connecting spring may be omitted. In this case, for example, the cleaning electrode may be in contact with the pressing member. Also, at least one of the pressing member and the cleaning electrode may be formed of a leaf spring, a wire spring, or the like.

The connecting spring is not limited to a coil spring, but may be a torsion spring, leaf spring, or other spring. The spring is not limited to a torsion spring, but may be a leaf spring, coil spring, or other spring.

The elements described in the above embodiments and variations may be combined in any manner.

50 Drum cartridge 51 Photosensitive drum 53 Cleaning roller 53A Cleaning shaft 54 Pressing member 56 Cleaning electrode

Claims (18)

a photosensitive drum rotatable about a drum axis extending in a first direction;
a cleaning roller in contact with the photosensitive drum, the cleaning roller having a cleaning shaft;
a pressing member that presses the cleaning roller against the photosensitive drum, the pressing member being in contact with an outer circumferential surface of the cleaning shaft;
a cleaning electrode electrically connected to the cleaning roller;
a connection spring that electrically connects the pressing member and the cleaning electrode,
the cleaning electrode is electrically connected to the cleaning roller via the connection spring and the pressing member ;
The drum cartridge according to claim 1, wherein the connecting spring is located between the pressing member and the cleaning electrode in the first direction . the cleaning roller is rotatable about a cleaning axis extending in the first direction,
2. The drum cartridge according to claim 1, wherein the pressing member presses the cleaning roller against the photosensitive drum in a second direction intersecting the first direction. The drum cartridge according to claim 2, characterized in that the second direction is perpendicular to the first direction. The drum cartridge according to claim 2 or 3, characterized in that the cleaning electrode is spaced apart from the cleaning shaft in the second direction. The drum cartridge according to any one of claims 2 to 4, characterized in that the cleaning shaft is located between the photosensitive drum and the pressing member in the second direction. 6. The drum cartridge according to claim 1 , wherein the connection spring is a coil spring that is expandable and contractible in the first direction. 7. The drum cartridge according to claim 6 , wherein the cleaning electrode has a first boss extending in the first direction, the first boss fitting into one end of the connection spring in the first direction. 8. The drum cartridge according to claim 7 , wherein the pressing member has a second boss extending in the first direction, the second boss fitting into the other end of the connection spring in the first direction. a photosensitive drum rotatable about a drum axis extending in a first direction;
a cleaning roller in contact with the photosensitive drum, the cleaning roller having a cleaning shaft;
a pressing member that presses the cleaning roller against the photosensitive drum, the pressing member being in contact with an outer circumferential surface of the cleaning shaft;
a cleaning electrode electrically connected to the cleaning roller;
a connection spring that electrically connects the pressing member and the cleaning electrode;
a drum frame that rotatably holds the photosensitive drum ,
the cleaning electrode is electrically connected to the cleaning roller via the connection spring and the pressing member;
The drum frame is
a restricting boss for restricting the movement of the pressing member in the first direction, The pressing member is
a contact portion that contacts the cleaning shaft;
10. The drum cartridge according to claim 9 , further comprising: a first wall extending from the contact portion to a side opposite to the cleaning shaft, the first wall being located between the regulating boss and the connecting spring. the pressing member has a second wall extending from the contact portion to a side opposite to the cleaning shaft,
11. The drum cartridge according to claim 10 , wherein the regulating boss is located between the first wall and the second wall in the first direction. a spring for biasing the pressing member toward the cleaning shaft,
12. The drum cartridge according to claim 9 , wherein the regulating boss holds the spring. The spring is a torsion spring having a coil portion and two arms,
13. The drum cartridge according to claim 12 , wherein the regulating boss is inserted into the coil portion. the drum cartridge is detachably attached to a main body housing having a main body electrode;
14. The drum cartridge according to claim 1, wherein the cleaning electrode is in contact with the main electrode when the drum cartridge is attached to the main body housing. The cleaning electrode is
a contact surface that comes into contact with the main body electrode when the drum cartridge is attached to the main body housing;
15. The drum cartridge according to claim 14 , further comprising a guide surface that guides the main body electrode to the contact surface during the process of mounting the drum cartridge to the main body case. 16. The drum cartridge according to claim 1 , wherein the cleaning electrode is made of a conductive resin. 17. The drum cartridge according to claim 1 , wherein the pressing member is made of a conductive resin. a photosensitive drum rotatable about a drum axis extending in a first direction;
a cleaning roller in contact with the photosensitive drum, the cleaning roller having a cleaning shaft;
a pressing member that presses the cleaning roller against the photosensitive drum, the pressing member being in contact with an outer circumferential surface of the cleaning shaft;
a cleaning electrode electrically connected to the cleaning roller,
the cleaning electrode is electrically connected to the cleaning roller via the pressing member;
the drum cartridge is detachably attached to a main body housing having a main body electrode;
The cleaning electrode is
a contact surface that comes into contact with the main body electrode when the drum cartridge is attached to the main body housing;
a guide surface that guides the main body electrode to the contact surface during the process of mounting the drum cartridge to the main body housing.

Images