JP2004354790A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To contribute to reduction of cost of components and assembly, by reducing the number of components, and to reduce loss in transmission torque. <P>SOLUTION: An image forming device comprises a photoreceptor drum 14, supported rotatably about a drum shaft 60; a developing device 13 for forming a toner image by supplying toner to the circumferential face of the photoreceptor drum 14; and a cleaning device 17 for performing cleaning, by removing the toner remaining on the circumferential face of the photoreceptor drum 14. The developing device 13 has a developing roller 51 supported rotatably in one piece around a developing roller shaft 50, in parallel with the drum shaft 60. The cleaning device 17 is an image forming device 10 that has a cleaning roller 71 supported integrally rotatably around a cleaning roller shaft 70, in parallel with the drum shaft 60. The developing roller shaft 50 is connected to the cleaning roller shaft 70 via a relay gear 64 supported rotatably around the drum shaft 60 to transmit the rotation at one part to the other part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a copying machine or a facsimile machine in which a developing device, a photosensitive drum, a cleaning device, and the like are provided, and an image forming apparatus such as various printers.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there have been known image forming apparatuses such as copiers and facsimile apparatuses in which a developing device, a photosensitive drum, a cleaning device, and the like are installed, and various printers. Such an image forming apparatus has a document image reading unit provided with a predetermined optical system, and image information read by the document image reading unit is electrically applied to the peripheral surface of the photosensitive drum and is statically placed on the peripheral surface. An electrostatic latent image is formed.
[0003]
The developing device supplies toner to the peripheral surface of the photosensitive drum rotating around the drum axis to form a toner image along an electrostatic latent image, and has a developing roller parallel to the drum axis. The rotation of the developing roller applies toner to the peripheral surface of the photosensitive drum.
[0004]
The photosensitive drum with the toner image formed on the peripheral surface transfers the toner image on the peripheral surface to paper separately fed by rotation around the drum axis, and the paper on which the toner image is transferred is fixed. After a predetermined fixing process is performed in the apparatus, the sheet is discharged out of the apparatus.
[0005]
On the other hand, the photosensitive drum after the transfer process to the paper is rotated around the drum axis while the toner remaining on the peripheral surface is removed by the cleaning device to be cleaned, and is prepared for the next electrostatic image formation.
[0006]
The cleaning device has a cleaning roller parallel to the drum axis. The cleaning roller rotates while abutting on the peripheral surface of the photosensitive drum, so that residual toner on the peripheral surface is wiped off.
[0007]
Normally, the driving force is transmitted to the cleaning roller directly via a gear fixed concentrically to the photosensitive drum or further via an idle gear, so that the driving force from the photosensitive drum is transmitted to the cleaning roller. With this configuration, there is a problem that fluctuations in the load of the cleaning roller affect the rotation of the photosensitive drum, and so-called driving unevenness (jitter) may occur in the transferred image.
[0008]
In order to avoid such a problem, it is conceivable that the rotation of the photosensitive drum and the rotation of the cleaning roller are performed by a driving force from another driving source. However, in this case, the number of parts increases. Not only raises the cost of parts but also raises the operating cost.
[0009]
As a solution to this new problem, Patent Document 1 discloses that a driving force from a driving source is transmitted to a developing roller and the rotation of the developing roller is transmitted through a gear group formed by combining a plurality of gears. A configuration in which the power is transmitted to the cleaning roller is disclosed.
[0010]
[Patent Document 1]
JP 2002-196585 A
[0011]
[Problems to be solved by the invention]
However, since the developing roller and the cleaning roller are arranged at positions opposing each other on the peripheral surface of the photosensitive drum, there is a method disclosed in Patent Document 1 in which the driving force of the developing roller is transmitted to the cleaning roller. As a result, a complicated structure having many gears must be adopted as the gear group, which not only raises the cost of parts and assembly but also increases the cost of driving through many gears. There is a problem in that the transmission of the force increases the transmission torque loss and increases the operating cost.
[0012]
The present invention has been made in order to solve the above-described problems, and it is possible to reduce the number of components while preventing driving unevenness from occurring in a transferred image. It is another object of the present invention to provide an image forming apparatus having a driving force transmission structure that can contribute to a reduction in assembly cost and a reduction in operation cost.
[0013]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a photosensitive drum rotatably supported around a drum axis, a developing device for forming a toner image on a peripheral surface of the photosensitive drum, and a developing device after the toner image is transferred to a sheet. A cleaning device that removes toner remaining on the peripheral surface of the photosensitive drum, wherein the developing device has a developing roller rotatably supported so as to be integrally rotatable around a developing roller axis parallel to the drum axis. An image forming apparatus comprising: a cleaning roller rotatably supported so as to be integrally rotatable about a cleaning roller axis parallel to the drum axis, wherein the developing roller axis; the cleaning roller axis; Is characterized in that one rotation is linked to the other rotation through a relay gear rotatably supported around the drum axis.
[0014]
According to the present invention, when the driving force of the predetermined driving source is transmitted to one of the developing roller shaft and the cleaning roller shaft, the transmitted driving force is rotatably supported around the drum shaft. The developing roller and the cleaning roller rotate at the same time, and a toner image is formed once on the peripheral surface of the photosensitive drum by the supply of toner from the developing roller, and the toner image is formed on the other shaft. After the image is transferred to the sheet, the residual toner remaining on the peripheral surface is removed by rotating the cleaning roller against the peripheral surface of the photosensitive drum.
[0015]
The two shafts have a driving force such that the rotation of one of the developing roller shaft and the cleaning roller shaft is transmitted to the other shaft via a relay gear rotatably supported around the drum shaft. As described above, a plurality of power transmission members, such as a plurality of power transmission gears and belts, are arranged in the circumferential direction of the photosensitive drum as in the related art. As compared with the case where the driving force of one shaft is transmitted to the other shaft (that is, the circuit makes a detour), the number of parts can be reduced, which contributes to the reduction of the parts cost and the assembly cost. In addition, the transmission torque crossing of the driving force is reduced by the reduction in the number of the driving force transmission members, which contributes to the reduction of the operating cost.
[0016]
According to a second aspect of the present invention, in the first aspect, the developing roller shaft has a developing roller gear that rotates concentrically and integrally, and the cleaning roller shaft has a cleaning roller gear that rotates concentrically and integrally. And each gear is meshed with the relay gear.
[0017]
According to the present invention, the driving force of one shaft is transmitted to the other shaft via the developing roller gear and the cleaning roller gear with the relay gear interposed therebetween. As described above, by transmitting the driving force by the gear, the driving force of one shaft is transmitted to the other shaft while ensuring good responsiveness and suppressing the transmission torque loss.
[0018]
According to a third aspect of the present invention, in the second aspect of the invention, the developing roller gear is meshed with an idle gear to which a driving force from a driving source is transmitted.
[0019]
According to the present invention, it is possible to transmit the driving force of the driving source to the developing roller shaft or the cleaning roller shaft while avoiding positional restrictions in a narrow device due to the presence of the idle gear, and the design is improved. The degree of freedom is improved.
[0020]
According to a fourth aspect of the present invention, in the first aspect of the present invention, a driving force from a driving source is transmitted to the developing roller shaft. is there.
[0021]
According to the present invention, the driving force of the driving source is changed in accordance with a temporal change in the peripheral surface of the photosensitive drum that a toner image is formed and the residual toner is removed after the toner image is transferred onto the paper. First, since the power is transmitted to the rotation of the developing roller shaft, it is possible to avoid the inconvenience that it becomes difficult to drive the developing roller with high accuracy and timing when the transmission of the driving force is reversed, and the precise timing This is effective in performing control.
[0022]
According to a fifth aspect of the present invention, in the first aspect of the present invention, the developing device can be separated from and connected to the photosensitive drum by rotating about a connection axis parallel to a drum axis. It is characterized by being connected.
[0023]
According to the present invention, maintenance work such as repairing and cleaning the inside of the developing device and the photosensitive drum can be easily performed by rotating the developing device around the connecting shaft so that the developing device can be separated from and brought into contact with the photosensitive drum. become.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a side view schematically illustrating an embodiment of an image forming apparatus according to the present invention. As shown in FIG. 1, the image forming apparatus 10 has a main body housing 11 in which an interior device including a drawer 20 that can be inserted and removed and a transport unit 30 mounted on the drawer 20 is mounted. And a yellow unit 12Y, a magenta unit 12M, a cyan unit 12C, and a black unit 12K which are sequentially arranged from the upstream side (left side of the paper surface of FIG. 1) to the downstream side. Image forming unit 12. Each of the units 12Y, 12M, 12C, and 12K is positioned and mounted on the main body housing 11 and each part in a predetermined relative positional relationship.
[0025]
Each of the units 12Y, 12M, 12C, and 12K includes a developing device 13 and a photosensitive drum 14, respectively. Each photosensitive drum 14 receives a supply of toner from the corresponding developing device 13 and rotates counterclockwise in FIG.
[0026]
A charging section 15 is provided at a position on the upper right side of each photosensitive drum 14 in FIG. 1, and an exposure section 16 is provided at a position on the upper left side in FIG. Each photosensitive drum 14 is uniformly charged on its peripheral surface by the charging unit 15, and an LED light based on image data input from a reader (not shown) is By irradiating the peripheral surface of the drum 14, an electrostatic latent image is formed on the peripheral surface of each photosensitive drum 14. By supplying toner from the toner container of the developing device 13 to the electrostatic latent image, a toner image is formed on the peripheral surface of the photosensitive drum 14.
[0027]
A transport unit 30 is provided below the photosensitive drums 14 while being mounted on the drawer 20. The transport unit 30 includes a base 31 mounted on the drawer body 20, and a transport belt 32 supported by the base 31 and rotating clockwise in FIG. The transport belt 32 includes a driving roller 33 provided at a right end of the base 31 in FIG. 1, a driven roller 34 provided at the left end thereof, and a slightly higher position between the driving roller 33 and the driven roller 34. It is wrapped around four rolling rollers 35 arranged at a pitch, and is circulated by the driving of the driving roller 33.
[0028]
Each of the rolling rollers 35 is pressed against a corresponding one of the photosensitive drums 14 via the transport belt 32, so that the transfer from the photosensitive drum 14 to the sheet transported by the transport belt 32 is performed reliably. It has become. Further, a cleaning device 17 for removing and cleaning residual toner on the peripheral surface of the photosensitive drum 14 is provided at a lower right position of each photosensitive drum 14 in FIG. The peripheral surface of the photosensitive drum 14 cleaned by the cleaning device 17 is directed to the charging unit 15 for a new charging process.
[0029]
The paper fed from the paper feed mechanism 18 provided below the drawer body 20 in the main body housing 11 as shown by an arrow is guided by the rotation of the transport belt 32 and rolled with each of the photosensitive drums 14. The sheet fed between the moving roller 35 and the transfer process by the black unit 12K is introduced into a fixing device 19 having a pair of fixing rollers (not shown), and is fixed by a heat fixing process in the fixing device 19. A color image is formed. The paper with the color image on which the fixing process has been completed is discharged to the discharge unit 110 through a predetermined conveyance path.
[0030]
The drawer body 20 can be inserted into and removed from the main body housing 11 in a state where the transport unit 30 in the image forming apparatus 10 configured as described above is mounted. The drawer body 20 extends in a width direction (a direction perpendicular to the paper surface of FIG. 1) and a pair of side plates 21, and extends from a lower portion of each side plate 21 toward the back of the main body housing 11 (to the right in FIG. 1). It comprises a pair of support arms 22 in the width direction and a construction frame (not shown) provided between the pair of side plates 21. The transport unit 30 is mounted on the drawer body 20 in a state where the first half (the left portion in FIG. 1) is supported by the pair of arms 22.
[0031]
On the other hand, an opening 112 is provided on the front surface (left side in FIG. 1) of the main body housing 11, and the drawer 20 can enter and exit the main body housing 11 through the opening 112. A pair of widthwise frames 113 extending in the up-down direction is provided at a position near the arm 22 of the side plate 21 in a state where the drawer body 20 is mounted on the main body housing 11 at the back of the opening 112. The drawer body 20 mounted inside is configured so that each side plate 21 is held between the pair of frames 113.
[0032]
The frame 113 is provided with an elongated engaging hole 114 extending vertically, while the side plate 21 is provided with a locking member 115 corresponding to the engaging hole 114. The state in which the drawer body 20 is attached to the inside of the main body housing 11 is maintained by engaging the engaging claw 115 with the edge of the engaging hole 114.
[0033]
2 and 3 are schematic side views showing the image forming unit. FIG. 2 shows a state in which the developing device 13 is closed with respect to the photosensitive drum 14, and FIG. Each of them shows an open state. FIG. 4 is a perspective view for explaining a driving force transmission structure between the developing roller of the developing device 13 and the cleaning roller of the cleaning device 17 in the image forming unit.
[0034]
First, as shown in FIG. 2, the image forming unit 100 includes the developing device 13, the photosensitive drum 14, the charging unit 15, the exposure unit 16, and the cleaning device 17.
[0035]
The developing device 13 is provided between the pair of side plates 131 and a pair of side plates 131 having an L-shaped width direction (a direction orthogonal to the paper surface of FIG. 2) composed of a vertical plate portion 132 and a horizontal plate portion 133. A toner hopper 134 for storing toner and a developing device side gear group 40 provided on the outer surface side of each side plate 131 are provided. The toner hopper 134 is formed on the side of the side plate 131 on the side of the vertical plate 132, while the developing device side gear group 40 is mounted mainly on the side of the side plate 131 on the side of the horizontal plate 133.
[0036]
At a lower position in the toner hopper 134, a stirring shaft 135 provided between the vertical plate portions 132 is provided. A stirring blade 136 is formed on the peripheral surface of the stirring shaft 135, and the toner in the toner hopper 134 is stirred by integrally rotating the stirring blade 135 around the stirring shaft 135.
[0037]
Further, a developing roller shaft 50 is provided between a pair of horizontal plate portions 133 in the toner hopper 134 between lower right positions in FIG. 2, and the developing roller shaft 50 is integrally formed with the developing roller shaft 50 concentrically. The toner stored in the photosensitive drum 143 is supplied toward the peripheral surface of the photosensitive drum 14 by the rotation of the developing roller 51 around the developing roller shaft 50.
[0038]
The developing device-side gear group 40 includes a drive gear 41 that rotates integrally around a drive shaft 42 supported at a substantially central position of the horizontal plate portion 133, and rotates around a first idle shaft 44 that meshes with the drive gear 41. A first idle gear 43 that is freely rotatably supported, a developing roller gear 45 that meshes with the first idle gear 43 and that is concentrically fixed to the developing roller shaft 50, and a vertical plate portion 132 and a horizontal plate portion 133. A second idle gear that meshes with the drive gear 41 while being rotatably supported about a second idle shaft 47 provided at a boundary position; and the stirring shaft 135 that meshes with the second idle gear 46. And an agitating gear 48 concentrically fixed to the shaft.
[0039]
As shown in FIG. 4, the drive shaft 42 has a joint member 421 formed concentrically at the tip thereof, and a drive shaft of a drive motor for a developing device (not shown) is connected to the joint member 421. Has become. Therefore, the rotational drive of the developing device drive motor is transmitted to the drive shaft 42 via the joint member 421, and the rotation of the drive shaft 42 about the axis thereof is performed by the first idle gear 43, the developing roller gear 45 and the developing roller shaft 45. The power is transmitted to the developing roller 51 via the second idle gear 46, the stirring gear 48, and the stirring shaft 135 to the stirring blade 136.
[0040]
The photosensitive drum 14, the charging unit 15, the exposure unit 16, and the cleaning device 17 are mounted on a housing 140 provided adjacent to the developing device 13. The housing 140 includes a pair of side plates 141 in the width direction, a top plate 145 provided between upper edges of the side plates 141, and a front plate 146 provided between front edges of the side plates 141 (right side in FIG. 2). And a bottom plate 147 provided between lower front edges of the side plates 141. The charging section 15 and the exposure section 16 are mounted on a top plate 145 of the housing 140, respectively.
[0041]
The side plate 141 has a substantially rectangular side plate main body 142, a protruding plate 143 protruding further forward from an upper front position of the side plate main body 142, and a lower edge of the side plate main body 142 for the developing device 13. And a projecting piece 144 projecting toward the direction. The protruding piece 144 is set at an installation position such that the lower edge of the horizontal plate portion 133 contacts the developing device 13 in a state where the developing device 13 is closed with respect to the housing 140 (FIG. 2).
[0042]
A drum chamber 148 for mounting the photosensitive drum 14 is formed in a space surrounded by the side plate main bodies 142 of the pair of side plates 141 and the top plate 145. The main part of the cleaning device 17 is mounted in a space (mounting space 149) surrounded by the protruding plate 143, the top plate 145, the front plate 146, and the bottom plate 147 of the side plate 141.
[0043]
The photosensitive drum 14 is mounted concentrically and integrally rotatable on a drum shaft 60 provided between substantially central positions of a pair of side plate bodies 142. As shown in FIG. 4, a drive shaft 62 of a drum drive motor 61 is concentrically connected to the drum shaft 60 via a joint member 63, and the drive shaft 62 is driven around the axis of the drive shaft 62 by the drive of the drum drive motor 61. The driving rotation is transmitted to the photosensitive drum 14 via the joint member 63 and the drum shaft 60.
[0044]
On such a drum shaft 60, a relay gear 64 meshing with the developing roller gear 45 is rotatably supported around the drum shaft 60. The inner diameter of the relay gear 64 is set to be slightly larger than the outer diameter of the drum shaft 60, and a plurality of bearing rollers are provided in an annular gap formed between the inner peripheral surface of the relay gear 64 and the outer peripheral surface of the drum shaft 60. The relay gear 64 can rotate smoothly around the drum shaft 60 by inserting the 65.
[0045]
The cleaning device 17 meshes with a cleaning roller shaft 70 provided between the pair of projecting plates 143 in the mounting space 149, a cleaning roller 71 fixed concentrically to the cleaning roller shaft 70, and the relay gear 64. A cleaning roller gear 72 concentrically fixed to the cleaning roller shaft 70, a screw shaft 80 extending between the pair of projecting plates 143 and parallel to the cleaning roller shaft 70, and fixed concentrically to the screw shaft 80. And a cleaning roller gear 82 concentrically fixed to a screw shaft 80 so as to mesh with the cleaning roller 71.
[0046]
Accordingly, the rotation of the driving gear 41 is transmitted to the cleaning roller gear 72 via the first idle gear 43, the developing roller gear 45, and the relay gear 64, whereby the cleaning roller 71 rotates integrally around the cleaning roller shaft 70, and When the rotation of the cleaning roller gear 72 is transmitted to the cleaning roller gear 82, the cleaning screw 81 integrally rotates around the screw shaft 80.
[0047]
The cleaning roller 71 has a diameter set so as to contact the peripheral surface of the photoconductor drum 14, and rotates around the cleaning roller shaft 70 in a state of contact with the peripheral surface of the photoconductor drum 14. The residual toner remaining on the peripheral surface of the photoreceptor drum 14 is removed by the peripheral speed difference therebetween.
[0048]
The cleaning screw 81 is for discharging the residual toner removed from the peripheral surface of the photosensitive drum 14 by the cleaning roller 71 and accumulated on the bottom plate 147. The residual toner on the bottom plate 147 is rotated on the bottom plate 147 by the rotation of the cleaning screw 81 about the screw shaft 80 toward the discharge hole 1471 provided at one end in the width direction (the direction orthogonal to the paper surface of FIG. 2). It is conveyed and discharged out of the system through the discharge hole 1471. The discharged residual toner is collected in a toner collection hopper (not shown).
[0049]
In the image forming unit 100 configured as described above, the developing device 13 can be separated from and brought into contact with the photosensitive drum 14. Specifically, the upper part of the side plate 131 of the developing device 13 at the rear (right side in FIG. 2) of the side plate 131 and the upper part of the front part of the side plate body 142 of the housing 140 containing the photosensitive drum 14 are connected to the connection shaft 101 The developing device 13 opens the housing 140 as shown in FIG. 3 by rotating the developing device 13 clockwise around the connecting shaft 101 in the state shown in FIG. State.
[0050]
The reason for this is that the repair work such as the replacement of parts in the image forming unit 100 and the work of cleaning the inner part can be easily performed, thereby facilitating the maintenance work.
[0051]
As described in detail above, the image forming apparatus 10 according to the present invention includes a photosensitive drum 14 rotatably supported around a drum shaft 60 and an electrostatic latent image formed on a peripheral surface thereof. A developing device 13 for supplying toner to the peripheral surface of the photosensitive drum 14 to form a toner image corresponding to the electrostatic latent image, and removing the toner remaining on the peripheral surface of the photosensitive drum 14 after the toner image is transferred onto the paper The developing device 13 includes a developing roller 51 that is rotatably supported around a developing roller shaft 50 that is parallel to the drum shaft 60. The developing roller shaft 50 and the cleaning roller shaft 70 are provided around the drum shaft 60. The cleaning roller 71 is rotatably supported about a cleaning roller shaft 70 parallel to the shaft 60. One rotation is linked to the other rotation via a rotatably supported relay gear 64 so that the driving force of a predetermined driving source (a driving motor for a developing device (not shown)) is reduced. When transmitted to the developing roller shaft 50, the transmitted driving force is transmitted to the cleaning roller shaft 70 via a relay gear 64 rotatably supported around the drum shaft 60, whereby the developing roller 51 and The cleaning roller 71 rotates at the same time, a toner image is once formed on the peripheral surface of the photosensitive drum 14 by the supply of the toner from the developing roller 51, and the toner image is transferred to a sheet and remains on the peripheral surface. Residual toner can be removed by rotating the cleaning roller 71 in contact with the peripheral surface of the photosensitive drum 14.
[0052]
In this manner, the rotation of the developing roller shaft 50 is transmitted to the cleaning roller shaft 70 via the developing roller gear 45, the relay gear 64, and the cleaning roller gear 72 (that is, the developing roller shaft 50 and the cleaning roller gear 72). The roller shaft 70 is linked to each other via the relay gear 64 so as to traverse the side portion of the photoconductor drum 14), and a plurality of gears for transmitting power in the circumferential direction of the photoconductor drum 14 as in the related art. The number of parts can be reduced as compared with a case where a driving force transmitting member such as a belt or a belt is provided and the driving force of one shaft is transmitted to the other shaft (that is, the circuit makes a detour). While contributing to the reduction of component costs and assembly costs, the reduction in the number of driving force transmitting members can reduce the driving torque transmission torque loss, It can contribute to the reduction of operating costs as result.
[0053]
The developing roller shaft 50 and the cleaning roller shaft 70 are linked to each other via the relay gear 64 via the developing roller gear 45 and the cleaning roller gear 72, so that good responsiveness is secured and transmission torque loss is suppressed. In this state, the driving force of the developing roller shaft 50 is efficiently transmitted to the cleaning roller shaft 70.
[0054]
Further, since the developing roller shaft 50 is configured to transmit a driving force from a driving source via the first idle gear 43, the presence of the first idle gear 43 restricts the position in a narrow device. Thus, it is possible to transmit the driving force of the driving source to the cleaning roller shaft 70 by avoiding the above problem, so that the degree of freedom in design can be improved.
[0055]
Since the driving force from the driving source is first transmitted to the developing roller shaft 50 and then to the cleaning roller shaft 70 via the relay gear 64, the driving force of the driving source is After the toner image is formed and transferred to a sheet, the toner image is transmitted in order in accordance with a temporal change in the peripheral surface of the photosensitive drum 14 in which the residual toner is removed. Therefore, it is possible to avoid such a problem that it is difficult to drive the developing roller 51 with good timing when the transmission of the driving force is reversed, which is effective in performing precise timing control.
[0056]
In the present embodiment, the developing device 13 and the photosensitive member 14 are connected to the photosensitive drum 14 in a detachable manner by rotation about a connecting shaft 101 parallel to the drum shaft 60. Maintenance work such as repair of the drum 14 and internal cleaning can be easily performed.
[0057]
The present invention is not limited to the above embodiments, but also includes the following contents.
[0058]
(1) In the above embodiment, the driving rotation of the driving shaft 42 of the developing device 13 is transmitted to the developing roller 51 via the first idle gear 43, the developing roller gear 45, and the developing roller shaft 50. However, the present invention is not limited to transmitting the driving rotation of the driving shaft 42 to the developing roller 51 via the first idle gear 43 and the developing roller gear 45, and instead of the developing roller shaft 50, Alternatively, the developing roller 51 may be mounted on the first idle shaft 44.
[0059]
In particular, when the developing roller 51 is provided on the drive shaft 42, the first idle gear 43, the developing roller gear 45 and the like are interposed before reaching the relay gear 64, so that the desired number of rotations of the developing roller 51 is secured. Then, by selecting the number and diameter of the interposed gears variously, the peripheral speed and the rotation direction of the relay gear 64 (and hence the rotation speed and the rotation direction of the cleaning screw 81) can be easily set. And the degree of freedom in design can be increased.
[0060]
(2) In the above embodiment, the developing roller gear 45 is driven and rotated first, and this rotation is transmitted to the cleaning roller gear 72 via the relay gear 64 supported by the drum shaft 60. Instead, the cleaning roller gear 72 may be driven and rotated first, and this rotation may be transmitted to the developing roller gear 45 via the relay gear 64.
[0061]
(3) In the above-described embodiment, the developing device 13 is connected to the housing 140 that houses the photosensitive drum 14 so as to be detachable (openable and closable) by forward and reverse rotation around the connection shaft 101. The present invention is not limited to the case where the developing device 13 is connected to the housing 140 so as to be openable and closable, and the two may be integrally connected.
[0062]
【The invention's effect】
According to the image forming apparatus of the present invention, the rotation of one of the developing roller shaft and the cleaning roller shaft is transmitted to the other shaft via the relay gear rotatably supported around the drum shaft. In addition, since both shafts are linked to each other in a state where the transmission of the driving force crosses the side of the photosensitive drum, a plurality of gears and belts for transmitting power in the circumferential direction of the photosensitive drum as in the related art are used. The number of parts can be reduced as compared with the case where the driving force transmitting member is disposed and the driving force of one axis is transmitted to the other axis (that is, the circuit makes a circuitous movement), and the cost of parts and the cost It is possible to contribute to the reduction of the assembling cost and to reduce the transmission torque crossing of the driving force by the reduction in the number of the driving force transmission members, thereby contributing to the reduction of the operation cost.
[Brief description of the drawings]
FIG. 1 is an explanatory side view schematically illustrating an embodiment of an image forming apparatus according to the present invention.
FIG. 2 is a schematic side view showing the image forming unit, and shows a state in which a developing device is closed with respect to a photosensitive drum.
FIG. 3 is a schematic side view showing the image forming unit, and shows a state where a developing device is opened with respect to a photosensitive drum.
FIG. 4 is a perspective view for explaining a driving force transmission structure between a developing roller of a developing device and a cleaning roller of a cleaning device in the image forming unit.
[Explanation of symbols]
Reference Signs List 10 Image forming apparatus 11 Main body casing
110 outlet 112 opening
113 Frame 114 Engagement hole
115 Lock member 12 Image forming unit
13 Developing device 131 Side plate
132 Vertical plate part 133 Horizontal plate part
134 Toner hopper 135 Stirring shaft
136 Stirrer blade 40 Developing device side gear group
41 drive gear 42 drive shaft
43 1st idle gear 44 1st idle shaft
45 Developing roller gear 46 Second idle gear
47 Second idle shaft 48 Stirring gear
50 Developing roller shaft 51 Developing roller
14 Photoreceptor drum 140 Housing
141 side plate 142 side plate main body
143 Projection plate 144 Projection piece
145 Top plate 146 Front plate
147 Bottom plate 148 Drum chamber
149 Mounting space 60 Drum shaft
61 Drum drive motor 62 Drive shaft
63 Joint member 64 Relay gear
65 Bearing roller 70 Cleaning roller shaft
71 Cleaning roller 72 Cleaning roller gear
80 Screw shaft 81 Cleaning screw
82 Cleaning roller gear
15 Charger 16 Exposure
17 Cleaning device 18 Paper feed mechanism
19 Fixing device 20 Drawer
21 Side plate 22 Support arm
30 transport unit 31 base
32 conveyor belt 33 drive roller
34 Follower roller 35 Roller roller

Claims (5)

A photosensitive drum rotatably supported around the drum axis, a developing device for forming a toner image on the peripheral surface of the photosensitive drum, and a residual toner image on the peripheral surface of the photosensitive drum after the toner image is transferred to a sheet of paper A cleaning device that removes toner that has been removed, the developing device includes a developing roller that is rotatably supported around a developing roller axis parallel to the drum axis, and the cleaning device includes the drum. An image forming apparatus having a cleaning roller rotatably supported so as to be integrally rotatable about a cleaning roller axis parallel to an axis,
The developing roller shaft and the cleaning roller shaft are linked to each other so that one rotation is transmitted to the other rotation via a relay gear rotatably supported around the drum shaft. Image forming apparatus. The developing roller shaft has a developing roller gear that rotates concentrically and integrally, the cleaning roller shaft has a cleaning roller gear that rotates concentrically and integrally, and each gear is meshed with the relay gear. The image forming apparatus according to claim 1. The image forming apparatus according to claim 2, wherein the developing roller gear is meshed with an idle gear to which a driving force from a driving source is transmitted. 4. The image forming apparatus according to claim 1, wherein a driving force from a driving source is transmitted to the developing roller shaft. 5. 5. The image forming apparatus according to claim 1, wherein the developing device is detachably connected to the photosensitive drum by rotation about a connection axis parallel to a drum axis. apparatus.

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