JP2012234068A - Drive transmission device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive transmission device capable of restricting damage of a planetary gear mechanism at the time of operation for attaching/detaching a body of rotation while securing an alignment effect, and an image forming apparatus.SOLUTION: A drive transmission device is equipped with a planetary gear mechanism comprising: a cylindrical housing; an internal gear provided in the housing; sun gears rotating by receiving rotational drive force from a driving source disposed coaxially with the internal gear; a plurality of planetary gears disposed circumferentially in the internal gear and engaging with the sun gears and the internal gear; carriers supporting the planetary gears rotatably and rotatable coaxially with the sun gears and the internal gear; and an output shaft provided in the carrier. The drive transmission device transmits rotational drive force to a body of rotation via a rotation shaft connected to the output shaft. The output shaft side of the housing and the end of the opposite side of the drive transmission device are fixed to each other by a fixing member, and energization control means energizes an electromagnet when attaching/detaching the body of rotation and stops energization of the electromagnet when the body of rotation is attached.

Description

  The present invention relates to a drive transmission device that transmits a rotational driving force from a drive source to a rotating body, and an image forming apparatus such as a copying machine, a printer, and a facsimile machine that includes the drive transmission device.

  In an electrophotographic copying machine or printer, an electrostatic latent image is formed on the surface of a rotating cylindrical image carrier (hereinafter referred to as a photosensitive drum), and toner is attached to the formed electrostatic latent image for development. Then, the toner image is primarily transferred onto an endless belt (hereinafter referred to as a transfer belt), further transferred onto a recording paper, and fixed to obtain an image.

  In an image forming apparatus, many rotating bodies are used such as an image carrier such as a photosensitive drum, a driving roller for driving a belt member such as an intermediate transfer belt or a transfer belt, and a conveying roller for conveying a recording material. ing. In general, high precision is required for driving such a rotating body. Therefore, a mechanism for transmitting the rotational driving force from the driving source to the rotating body to be driven in a state where the rotational fluctuation is small is desired. In particular, when speed fluctuation occurs in the surface moving speed of a photosensitive drum or an intermediate transfer belt, jitter and density unevenness occur on the output image. That is, if the speed fluctuation continues at a certain frequency on the photosensitive drum or the intermediate transfer belt, periodic density unevenness occurs in the entire image, which is visually observed as banding of a striped pattern. In addition, the speed fluctuation of the photosensitive drum causes a sub-scanning position shift of the exposure line of the writing system, or a sub-scanning position shift at the time of the primary transfer of the toner image from the photosensitive drum to the intermediate transfer belt. On the other hand, the speed fluctuation of the intermediate transfer belt causes a sub-scanning position shift between the primary transfer and the secondary transfer. Image quality is significantly degraded by banding due to this speed variation.

  A plastic gear formed by injecting a molten resin is used for a drive transmission portion of such a photosensitive drum or an intermediate transfer belt that requires high precision driving. Plastic gears are superior to metal gears in that they are self-lubricating, have low noise during use, can be reduced in weight, have high corrosion resistance, and have high mass productivity. On the other hand, durability (wear resistance), high accuracy, and high rigidity are inferior to metal gears.

  It has been proposed to use a planetary gear mechanism so that sufficient durability can be obtained even when a plastic gear is used (for example, Patent Document 1). The planetary gear mechanism includes a resin-made cylindrical housing, a sun gear that rotates by receiving the rotational driving force of a drive source, an internal gear that is formed integrally with the housing and is arranged coaxially with the sun gear, A plurality of planetary gears arranged at equal intervals in the circumferential direction in the internal gear and meshed with the sun gear and the internal gear, and rotatably support the planetary gear and rotate coaxially with the sun gear and the internal gear. With a possible carrier. By rotating the sun gear by the rotational driving force from the drive source, a plurality of planetary gears revolve around the sun gear while rotating the carrier while rotating in the internal gear. The rotational driving force generated by the rotation of the carrier is transmitted to the rotating body via the output shaft of the carrier and the rotating shaft of the rotating body connected to the output shaft. For this reason, the rotational load is dispersed by the plurality of planetary gears, so that durability can be obtained even when plastic gears are used.

  In the image forming apparatus, a motor that is a drive source for rotationally driving a rotating body such as a photosensitive drum is provided. However, the rotational speed of the motor is generally larger than the rotational speed required for the rotation of the rotating body. In the image forming apparatus described in Patent Document 2, a drive transmission device that uses a planetary gear mechanism to reduce the rotational speed of a motor and transmits the reduced speed to a rotating body is used.

  In the configuration in which the rotational driving force from the driving source is transmitted to the rotating body via the drive transmission device provided with the planetary gear mechanism, the connecting portion between the output shaft of the carrier of the planetary gear mechanism and the rotating shaft of the rotating body is used as the shaft. If there is a concentric error due to misalignment or the like, uneven rotation occurs when the rotating body is rotated.

  On the other hand, as a result of intensive studies, the inventors of the present application have deformed the output shaft end of the planetary gear mechanism housing so that the rotation shaft of the rotating body and the output shaft of the carrier are aligned. As a result, it has been found that alignment is achieved and rotation irregularities of the rotating body can be reduced. Then, the end on the opposite side of the output shaft side of the housing is fixed to a fixing member such as a side plate, and the end on the output shaft side of the housing is not fixed to a fixing member such as a side plate. Alignment could be performed by bending the end of the housing on the output shaft side in the radial direction.

  In general, a rotating body such as a photosensitive drum provided in an image forming apparatus is configured so that the rotating body can be attached to and detached from the image forming apparatus in the direction of the rotation axis so that the rotating body can be replaced when it reaches the end of its life. There are many. Therefore, when a large radial force is applied to the rotating shaft of the rotating body during the attaching / detaching operation of the rotating body, the force is transmitted from the rotating shaft to the end of the housing on the output shaft side of the carrier and fixed. There is a risk that the planetary gear mechanism may be damaged due to excessive deflection in the radial direction of the output shaft side end of the housing that is not.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a drive transmission device capable of suppressing the damage of the planetary gear mechanism during the attaching / detaching operation of the rotating body while ensuring the alignment effect, and the drive transmission thereof. An image forming apparatus including the apparatus is provided.

In order to achieve the above-mentioned object, the invention of claim 1 includes a cylindrical housing, an internal gear provided in the housing, a rotational drive from a drive source disposed coaxially with the internal gear. A sun gear that rotates in response to a force, a plurality of planetary gears disposed in a circumferential direction in the internal gear and meshing with the sun gear and the internal gear, the planetary gear rotatably supported and A planetary gear mechanism comprising a carrier that is rotatable coaxially with the sun gear and the internal gear, and an output shaft that is provided on the carrier and outputs a rotational driving force. In a drive transmission device that transmits to a rotating body that can be attached to and detached from the apparatus main body via a rotating shaft connected to the output shaft, a fixing member that fixes an end of the housing opposite to the output shaft side; Electromagnetic provided on the device body And an energization control means for controlling energization to the electromagnet, and provided at an end of the housing on the output shaft side so as to face the electromagnet. When the electromagnet is energized, the electromagnet is electromagnetically attracted and fixed. And a member to be attracted to which electromagnetic attraction to the electromagnet is released when energized. When the rotating body is attached to or detached from the apparatus main body, the electromagnet is energized by the energization control means, and the apparatus main body is rotated. When the body is mounted, the energization control means stops energization of the electromagnet.
According to a second aspect of the present invention, in the drive transmission device of the first aspect, the housing and the internal gear are integrally formed.
According to a third aspect of the present invention, in the drive transmission device according to the first or second aspect, there is provided a restricting means for restricting a position of the rotating shaft in the axial direction.
According to a fourth aspect of the present invention, in the drive transmission device according to the first, second, or third aspect, the planetary gear mechanism has a plurality of stages in the axial direction within the housing.
According to a fifth aspect of the present invention, there is provided an image carrier, a driving means for rotationally driving the image carrier, and a rotational driving force connected to the image carrier and the driving means from the driving means. An image forming apparatus comprising a drive transmission means for transmitting to the image carrier and an image forming means for forming an image on the image carrier, wherein the drive transmission apparatus according to claim 1, 2, 3, or 4 is used as the drive transmission means. It is characterized by the fact that
According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the image carrier can be inserted into and removed from the rotating shaft, and when the rotating member is inserted into and removed from the rotating shaft, Interlocking with the rotating body's insertion / removal operation so that the attracting member is electromagnetically attracted to the electromagnet and the attracting member is released when the image carrier is mounted at a predetermined position of the rotating shaft. Thus, the energization control means controls energization to the electromagnet.
According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth or sixth aspect, the image carrier and at least one selected from a developing unit, a charging unit, and a cleaning unit are integrally configured to form an image forming apparatus. A process cartridge that can be attached to and detached from the main body is provided, and when the process cartridge is attached to and detached from the apparatus main body, the attracted member is electromagnetically attracted to the electromagnet, and the process cartridge is placed at a predetermined position on the apparatus main body. The energization control means controls the energization of the electromagnet in conjunction with the attaching / detaching operation of the process cartridge so that the electromagnetic attraction of the attracted member is released when it is mounted. .
According to an eighth aspect of the present invention, in the image forming apparatus of the seventh aspect, a positioning member for positioning the process cartridge with respect to the apparatus main body is provided in the process cartridge, and the energization control means supplies the energization to the electromagnet. And a switch for switching between de-energization, the switch is operated in conjunction with the movement of the positioning member by the attachment and detachment operation of the process cartridge, and the energization and de-energization of the electromagnet are switched. To do.

In the present invention, when the rotating body is attached to and detached from the apparatus main body, the energization control means energizes the electromagnet to cause the attracted member to be electromagnetically attracted to the electromagnet, and the housing on the output shaft side through the attracted member. Fix the end with an electromagnet. Thereby, the rotating body can be attached and detached while the end of the housing on the output shaft side is fixed. Therefore, even if the radial force applied to the rotating shaft when the rotating body is attached to or detached from the apparatus body is transmitted to the output shaft end of the housing via the output shaft, the output shaft of the housing It is possible to suppress the end portion on the side from bending in the radial direction. Therefore, it is possible to suppress the end portion on the output shaft side of the housing from being greatly bent and damaged.
In addition, when the rotating body is mounted on the apparatus main body, the energization control means stops energization of the electromagnet to release the electromagnetic adsorption of the attracted member to the electromagnet, and the end on the output shaft side of the housing is not fixed. To do. Thus, when the rotating body is mounted on the apparatus main body, the end on the output shaft side of the housing can be bent and deformed in the radial direction according to the concentric error between the rotation shaft and the output shaft. Therefore, the rotating shaft and the output shaft are aligned, and the rotation unevenness of the rotating body can be reduced.

  As described above, according to the present invention, there is an excellent effect that the planetary gear mechanism can be prevented from being damaged during the attaching / detaching operation of the rotating body while securing the alignment effect.

The figure when a photoconductor drum is mounted. 1 is a schematic configuration diagram of a copier according to an embodiment. Explanatory drawing of the planetary gear reduction device which drives a photosensitive drum. The schematic block diagram of an electromagnetic brake. The control block diagram of an electromagnetic brake. The figure when a photoconductor drum is pulled out.

  FIG. 2 is a schematic configuration diagram showing an example of a copying machine as an image forming apparatus to which the planetary gear device of the present invention is applied. In FIG. 2, reference numeral 100 denotes a copying machine main body, reference numeral 200 denotes a paper feed table on which the copying machine is placed, reference numeral 300 denotes a scanner mounted on the copying machine main body 100, and reference numeral 400 further denotes an automatic document transport mounted thereon. Device (ADF). This copier is a tandem type electrophotographic copier that employs an intermediate transfer (indirect transfer) system.

  In the center of the copying machine main body 100, an intermediate transfer belt 10 including a belt which is an intermediate transfer member serving as an image carrier is provided. The intermediate transfer belt 10 is stretched around a first support roller 81, a second support roller 82, and a third support roller 83 as three support rotating bodies, and rotates in a clockwise direction in the drawing. On the left side of the second support roller 82 in the drawing, an intermediate transfer belt cleaning device 84 for removing residual toner remaining on the intermediate transfer belt 10 after image transfer is provided.

Further, in the belt portion stretched between the first support roller 81 and the second support roller 82, yellow (Y), magenta (M), cyan (C), black ( The tandem image forming unit 86 in which the four image forming units 85 of K) are arranged side by side is arranged to face each other. In the present embodiment, the third support roller 83 is a drive roller. An exposure device 87 as a latent image forming unit is provided above the tandem image forming unit 86.

  A secondary transfer device 88 as a second transfer unit is provided on the opposite side of the tandem image forming unit 86 with the intermediate transfer belt 10 interposed therebetween. In the secondary transfer device 88, a secondary transfer belt 89, which is a belt as a recording material conveying member, is stretched between the rollers 23a and 23b. The secondary transfer belt 89 is provided so as to be pressed against the third support roller 83 via the intermediate transfer belt 10. By this secondary transfer device 88, the image on the intermediate transfer belt 10 is transferred to a sheet as a recording material.

  A fixing device 25 for fixing the image transferred on the sheet is provided on the left side of the secondary transfer device 88 in the drawing. The fixing device 25 has a configuration in which a pressure roller 27 is pressed against a fixing belt 26 that is a belt. The secondary transfer device 88 described above also has a sheet transport function for transporting the image-transferred sheet to the fixing device 25. Of course, a transfer roller or a non-contact charger may be disposed as the secondary transfer device 88. In such a case, it is difficult to provide this sheet conveying function together.

  In the present embodiment, a sheet reversing device for reversing the sheet so as to record images on both sides of the sheet is provided below the secondary transfer device 88 and the fixing device 25 in parallel with the tandem image forming unit 86 described above. 28 is also provided.

  When making a copy using the copying machine, a document is set on the document table 30 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed by it. Thereafter, when a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is conveyed and moved onto the contact glass 32. On the other hand, when an original is set on the contact glass 32, the scanner 300 is immediately driven. Next, the first traveling body 33 and the second traveling body 34 travel. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34 and reflects by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.

  In parallel with this document reading, a third support roller 83 as a drive roller is driven to rotate by a drive motor as a drive source (not shown). As a result, the intermediate transfer belt 10 moves in the clockwise direction in the drawing, and the first support roller 81 and the second support roller 82 rotate with the movement. At the same time, the photosensitive drums 40Y, 40M, 40C, and 40K as the latent image carriers are rotated in the individual image forming units 85Y, 85M, 85C, and 85K, and the photosensitive drums 40Y, 40M, 40C, and 40K are rotated. On top of this, exposure and development are respectively performed using information for each color of yellow, magenta, cyan, and black to form a single color toner image (developed image). Then, the toner images on the photosensitive drums 40Y, 40M, 40C, and 40K are sequentially transferred onto the intermediate transfer belt 10 so as to overlap each other, thereby forming a composite color image on the intermediate transfer belt 10.

  In parallel with such image formation, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and the sheet is fed out from one of the paper feed cassettes 44 provided in the paper bank 43 in multiple stages. The sheets are separated one by one and placed in the paper feed path 46, transported by the transport roller 47, guided to the paper feed path in the copying machine main body 100, and abutted against the registration roller 49 and stopped. Alternatively, the manual feed roller 50 is rotated to feed out the sheets on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped. Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer belt 10, the sheet is fed between the intermediate transfer belt 10 and the secondary transfer device 88, and is transferred by the secondary transfer device 88. A color image is transferred onto the sheet.

  The image-transferred sheet is conveyed by the secondary transfer belt 89 and sent to the fixing device 25. The fixing device 25 applies heat and pressure to fix the transferred image, and is then switched by the switching claw 55 to be discharged by the discharge roller 56. Are discharged and stacked on the discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and an image is also recorded on the back side of the sheet, and then discharged onto the discharge tray 57 by the discharge roller 56. .

  The intermediate transfer belt 10 after the image transfer is removed by the intermediate transfer belt cleaning device 84 to remove residual toner remaining on the intermediate transfer belt 10 after the image transfer, so that the tandem image forming unit 86 can prepare for another image formation. Here, the registration roller 49 is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

  This copier can be used to make a black and white copy. In that case, the intermediate transfer belt 10 is separated from the photosensitive drums 40Y, 40M, and 40C by means not shown. These photosensitive drums 40Y, 40M, and 40C are temporarily stopped from driving. Only the black photosensitive drum 40K is brought into contact with the intermediate transfer belt 10 to perform image formation and transfer.

FIG. 3 is an explanatory diagram of a planetary gear reduction device that drives the photosensitive drum 40.
The planetary gear reduction mechanism of the embodiment used in the photosensitive drum driving device shown in FIG. 3 is a 2KH type two-stage planetary gear mechanism. Since the planetary gear reduction device is composed of a two-stage planetary gear mechanism, the reduction ratio can be increased and the load on the motor can be reduced, so that the motor can be downsized.

  This is a first stage planetary gear that includes the first sun gear 12 provided on the rotation shaft M1 of the motor 60 and meshes with the first sun gear 12 and the internal gear 14 fixed to the internal gear fixing flange 24. The first planetary gear 15 is supported by a first carrier 16 that is a first-stage carrier and revolves around the outer periphery of the first sun gear 12. The first planetary gear 15 is concentrically arranged at three or more positions for rotational balance and torque sharing. In the present embodiment, the first planetary gears 15 are arranged at positions equally divided into three in the circumferential direction.

  The first planetary gear 15 rotates and revolves by the meshing of the first sun gear 12 and the internal gear 14, and the first carrier 16 that supports the first planetary gear 15 rotates the first sun gear 12. In contrast, the vehicle rotates at a reduced speed to obtain the first stage reduction ratio.

  Next, the second sun gear 17, which is a second stage sun gear provided at the rotation center of the first carrier 16, serves as an input to the second stage reduction mechanism. Note that the first carrier 16 does not have a rotation support portion and performs floating rotation.

  Similarly, in the second sun gear 17, a second planetary gear 18 that is a second stage planetary gear meshing with the internal gear 14 that is integrally formed up to the second stage is a second carrier that is a second stage carrier. The outer periphery of the second sun gear 17 is revolved by being supported by the carrier 19. In the present embodiment, the number of second planetary gears 18 is such that the second planetary gears 18 are arranged at positions that are divided into four equal parts in the circumferential direction. The second carrier 19 corresponding to the final stage is provided with an output portion, and spline-shaped internal teeth are formed on the inner surface of the cylindrical shaft 20 which is a cylindrical output shaft.

  Further, since the internal gear 14 is integrally configured with the housing of the planetary gear reduction device, the number of parts can be reduced, so that space saving and cost reduction can be achieved.

  On the other hand, the drum shaft 70 is formed with spline-shaped outer teeth so as to mesh with the spline-shaped inner teeth of the cylindrical shaft 20, and is provided with a spline portion 21 used as an output portion.

  Here, one unit used for the 2KH type planetary gear mechanism includes a sun gear, a planetary gear, a planetary carrier that supports the revolving motion of the planetary gear, and an internal gear (outer). gear) of four parts.

  Of the three elements that are sun gear rotation, planetary gear revolution (carrier rotation), and outer ring gear rotation, one is fixed, one is input, and one is connected to the output. Depending on which one is assigned to input / output / fixed, multiple reduction ratios and rotation directions can be switched with one unit.

  The 2KH type two-stage structure that is the object of the present embodiment is classified into compound planetary gear mechanisms (two or more 2KH types), and there are two or more 2KH types, each of which is one element out of three elements. This is a mechanism that couples each other, fixes the remaining one by one, and uses the remaining two as an input shaft or output shaft.

  The reduction ratio is expressed by Equation 1 when the number of teeth of the sun gear is Za, the number of teeth of the planetary gear is Zb, and the number of teeth of the internal gear is Zc. The subscripts 1 and 2 in the formula mean the first and second stages.

  The rotating shaft M1 of the motor 60 described above is supported by the motor fixing flange 13 via two bearings (not shown).

  By supporting the rotating shaft M1 of the motor 60, the outer rotor that is the rotor of the DC brushless motor is supported. The motor fixing flange 13 is also provided with a stator core (not shown) of the motor 60, a motor drive circuit board, and the like.

  The first sun gear 12 is formed by gear cutting on the rotation shaft M1 of the motor 60, and the internal gear 14 is secured in order to ensure the coaxial accuracy between the shaft of the first sun gear 12 and the shaft of the internal gear 14. The motor fixing flange 13 is positioned by fitting with an inlay, and the motor fixing flange 13 is positioned by fitting with an internal gear fixing flange 24 with an inlay.

  An end cap 22 is fixed to the end of the internal gear 14 opposite to the motor fixing flange 13. The end cap 22 has a first planetary gear 15, a second planetary gear 18, a first carrier 16, a second carrier 19, which are installed in the internal gear 14 when the planetary reduction mechanism is assembled to the drive side plate 127. And it is used as a member for preventing the cylindrical shaft 20 from falling off the internal gear 14. There is sufficient clearance between the end cap 22 and the cylindrical shaft 20 of the second carrier 19 so that the end cap 22 does not support the second carrier 19 in rotation and the second carrier 19 performs floating rotation. It has become.

FIG. 1 is a view showing a state where the photosensitive drum 40 is mounted on the planetary gear reduction device.
Since each of the photoconductor drums 40Y, 40M, 40C, and 40Bk is driven to rotate by the photoconductor drum drive device having the same configuration, the photoconductor drum drive device of the photoconductor drum 40Y will be described below. Although not explained, the present invention can also be applied to a driving roller of the intermediate transfer belt 10.

  First, the configuration of a photosensitive drum unit that is a process cartridge that can be attached to and detached from the copying machine main body 100 will be described. A rear drum flange 115 and a front drum flange 114 are fixed to the end of the photosensitive drum 40 in the axial direction, and the front and rear drum flanges are supported by the drum shaft 70. The rear drum flange 115 is connected to the drum shaft 70 by a serration coupling 116, and when the drum shaft 70 rotates, the photosensitive drum 40 rotates synchronously. The serration coupling 116 is provided with a male shape on the drum shaft side and a female shape on the rear drum flange 115 side, and is tapered from the front side of the drum shaft.

  In the unit case 117 of the photosensitive drum unit, a photosensitive drum 40Y, a charger 2Y, a developing device 9Y, a cleaning device 4Y, a static elimination lamp (not shown), and the like are accommodated and integrally supported by the unit case 117. . The rear side of the unit case 117 is supported by one of the two bearings 123a fixed to the drum shaft 70 with the collar 124 interposed therebetween in the axial direction, and the rear drum flange 115 is also supported by the bearing 123a. Thus, the photosensitive drum 40 and the unit case 117 are positioned. On the front side, the boss portion 128 of the front drum flange 114 is fitted with the unit case 117 and is rotatable.

  The drum shaft 70 is further provided with the other bearing 123b of the two bearings at a portion where the drum shaft 70 is fitted with the main body rear side plate 119, and is positioned with the main body rear side plate 119. The main body front side plate 110 is provided with a notch for attaching and detaching the photosensitive drum unit, and a face plate 111 is fixed thereto. A front end portion of the drum shaft 70 is rotatably supported by the face plate 111 via a bearing 112.

  The photosensitive drum unit can be attached and detached by removing the face plate 111. When the photosensitive drum unit is mounted, the photosensitive drum 40 is applied in the drum axial direction by the pressure spring 113 provided between the bearing 112 fixed to the face plate 111 and the boss portion 128 of the front drum flange 114. As a result, the rotational direction and the thrust direction are positioned at the portion of the tapered serration coupling 116. In the photosensitive drum unit, the two positioning pins 118 provided on the rear side of the unit case 117 are fitted into the holes of the main body rear plate 119, and the position in the rotation direction is determined.

The installation of the planetary gear reduction device will be described.
A driving side plate 127 is attached to the main body rear side plate 119 via a stud 126. An internal gear fixing flange 24 that supports the planetary gear reduction device is fixed and assembled to the drive side plate 127. The planetary gear reduction device is positioned by fitting the internal gear 14 into a hole provided in the drive side plate 127. Further, the planetary gear reduction device may be attached in a configuration in which the drive side plate 127 also serves as the internal gear fixing flange 24. In this way, the planetary gear reduction device is attached to the drive side plate 127, so that the output side of the internal gear 14 is free to be easily deformed.

  Next, a configuration for supporting the tip of the internal gear 14 (the end of the internal gear 14 on the cylindrical shaft side) when the photosensitive drum 40 is taken out from the main body will be described.

FIG. 4 is a diagram showing the configuration of the electromagnetic brake 130.
The electromagnetic brake 130 includes a pedestal 132, a field core 134, an electromagnetic coil 133 provided therein, a friction pad 135, an armature 136, a spring disk 137, and an output drive hub 131, and in this embodiment, the output drive hub 131. Is a support member for the tip of the internal gear 14. A spring disk 137 is fixed to the armature 136 and can be displaced in the direction of the arrow in the figure. An output drive hub 131 is fixed to the spring disk 137. An electromagnet is configured by the field core 134, the coil 133, and the like, and an electromagnetic field that attracts the armature 136 to the field core 134 can be generated by applying a voltage to the coil 133 by a power source (not shown). At this time, the armature 136 moves toward the field core 134 against the biasing force from the spring disk 137.

  The field core 134 is fixed to the pedestal 132 concentrically with the spigot portion 132a. When a voltage is applied to the electromagnetic coil 133, the armature 136 is connected to the electromagnet composed of the electromagnetic coil 133, the field core 134, etc. via the friction pad 135. Is electromagnetically attracted and fixed in a non-rotatable state from a rotation-free state.

  In a state where no voltage is applied to the electromagnetic coil 133, the armature 136 is pulled away from the field core 136 side by the urging force from the spring disk 137, and a gap is provided between the friction pad 135 and the armature 136. Also, a gap adjusting collar 138 is provided so that the gap interval is constant. In the present embodiment, the collar 138 is disposed between the pedestal 132 and the output drive hub 131 to adjust the gap interval.

  The armature 136 is disposed concentrically with the field core 134. However, the armature 136 can move in the radial direction by the gap with the collar 138. Accordingly, the output drive hub 131 can also move in the radial direction. ing.

  An electromagnetic brake 130 is fixed coaxially with the drum shaft 70 on the outer side of the rear plate of the main body. The electromagnetic brake 130 supports the drum shaft 70 and has an inlay between a bearing 123b and a pedestal 132 supported by the main body rear plate 119. The portion 132a is fitted and positioned.

  The output drive hub 131 of the electromagnetic brake 130 has a cup shape that opens toward the planetary gear reduction device as a support member for the tip portion of the internal gear 14, and the opening end portion of the internal drive gear 14 It is mated.

  At the center of the electromagnetic brake 130, the drum shaft 70 passes through and is connected to the cylindrical shaft 20 of the planetary gear reduction device. The connecting portion between the drum shaft 70 and the cylindrical shaft 20 in the present embodiment is a spline and joint method, but other connecting methods may be used, and the cylindrical shaft 20 and the drum shaft 70 of the second carrier 19 may be configured to be press-fitted. , Integrally processed may be used.

  Further, the drum shaft 70 is restricted so as not to come off in the thrust direction (axial direction). That is, the bearing 123b press-fitted into the drum shaft 70 on the planetary gear reduction device side in the thrust direction is regulated by the pedestal 132 of the electromagnetic brake 130, and on the opposite side between the output drive hub 131 and the planetary gear reduction device. It is regulated by the provided retaining ring 125.

  As shown in FIG. 1, when the photosensitive drum 40 is mounted on the planetary gear reduction device, the electromagnetic brake 130 is in an OFF state where no current flows. The output drive hub 131 is provided with radial play relative to the electromagnetic brake 130 so that the distal end portion of the internal gear 14 is free to bend. Therefore, even if there is a concentric error in the connecting portion between the drum shaft 70 that drives the photosensitive drum 40 and the cylindrical shaft 20 of the planetary gear reduction device, the tip of the internal gear 14 is bent and the internal gear 14 is deformed. Accordingly, the rotation transmission error can be reduced by aligning, and the rotation unevenness of the photosensitive drum 40 can be suppressed.

The ON / OFF control of the electromagnetic brake 130 will be described.
A micro switch 140 that controls energization of a coil 133 from a power source (not shown) to turn on and off the applied electromagnetic brake 130 is disposed on the surface of the main body rear plate 119 on the planetary gear reduction device side. The position is a position where the lever 142 of the micro switch 140 is pushed up away from the push button 141 at the tip of the positioning pin 118 when the positioning pin 118 of the unit case 117 penetrates through the hole of the rear plate 119 of the main body.

  The micro switch 140 is configured such that when the photosensitive drum 40 is not mounted on the planetary gear speed reduction device, the lever 142 is pushed by pushing the push button 141 to be turned on and the electromagnetic brake 130 is turned on. As shown in FIG. 1, when the photosensitive drum 40 is mounted on the planetary gear reduction device, the lever 142 is pushed up by the positioning pin 118 of the unit case 117, and the lever 142 is separated from the push button 141, and the micro switch 140 is moved. Is turned off, the energization is stopped, and the electromagnetic brake 130 is turned off.

FIG. 5 is a control block diagram of the electromagnetic brake 130.
In response to the ON / OFF signal from the micro switch 140, the control circuit 150 which is the driver of the electromagnetic brake 130 controls the operation (ON / OFF) of the electromagnetic brake 130. When the electromagnetic brake 130 is turned on, a voltage is applied to the electromagnetic coil 133 and a current flows. Then, an electromagnetic field is generated, and the armature 136 is attracted to the friction pad 135 against the urging force from the spring disk 137, and an electromagnetic including the electromagnetic coil 133, the field core 134, etc. The output drive hub 131 is fixed to the electromagnetic brake 130 by suction. When the electromagnetic brake 130 is turned off, no current flows through the electromagnetic coil 133 and no electromagnetic field is generated. Therefore, the armature 136 is pulled back to the original state by the spring disk 137, and the output drive hub 131 is released.

FIG. 6 shows a view when the photosensitive drum 40 is pulled out from the planetary gear reduction device.
When the face plate 111 is detached from the main body front side plate 110 and the unit case 117 is pulled out, the photoconductive drum 40 is also pulled out together with the serration coupling 116 with the drum shaft 70 removed. As a result, the lever 142 of the micro switch 140 that has been pushed by the positioning pin 118 of the unit case 117 returns to the original state, and the push button 141 is pushed by the lever 142 and the micro switch 140 is turned on to energize the electromagnetic brake 130. Is turned on.

  When the electromagnetic brake 130 is turned on in this way, the output drive hub 131 is fixed to the electromagnetic brake 130, and the tip of the internal gear 14 supported by the output drive hub 131 is fixed so as not to move in the radial direction. The As a result, the unit case 117 can be attached and detached while the tip of the internal gear 14 is fixed. Therefore, the radial force applied to the drum shaft 70 during the attaching and detaching operation of the unit case 117 causes the cylindrical shaft 20 to be attached. Even if it is transmitted to the tip portion of the internal gear 14 via the inner gear 14, it is possible to suppress the tip portion of the internal gear 14 from being bent in the radial direction (radial direction). Therefore, it can suppress that the front-end | tip part of the internal gear 14 deform | transforms too much at the time of attachment / detachment operation of the unit case 117, and is damaged.

As described above, according to the present embodiment, a cylindrical housing, an internal gear provided in the housing, and a sun gear that is arranged coaxially with the internal gear and rotates by receiving a rotational driving force from a driving source. A plurality of planetary gears arranged in a circumferential direction in the internal gear and meshing with the sun gear and the internal gear, and rotatably supporting the planetary gear and coaxially rotatable with the sun gear and the internal gear. A planetary gear mechanism comprising a carrier and an output shaft provided on the carrier for outputting rotational driving force is provided, and the rotational driving force from the drive source is applied to the device body via a rotational shaft connected to the output shaft. In the drive transmission device that transmits to the detachable rotating body, a fixing member that fixes the end of the housing opposite to the output shaft side, an electromagnetic brake that is an electromagnet provided in the device main body, and an electromagnetic brake Energization control to control energization It is provided at the end of the housing on the output shaft side so as to oppose the electromagnetic brake, and is electromagnetically attracted and fixed to the electromagnetic brake when the electromagnetic brake is energized, and the electromagnetic adsorption to the electromagnetic brake is released when the electromagnetic brake is not energized The electromagnetic brake is energized by the energization control means when the rotating body is attached to and detached from the apparatus main body, and the energization control means is attached when the rotating body is attached to the apparatus main body. To stop energization of the electromagnetic brake. When the rotating body is attached to or detached from the apparatus main body, the electromagnetic brake is energized by the energization control means so that the attracted member is attracted to the electromagnetic brake, and the end of the housing on the output shaft side is attached via the attracted member. Secure with an electromagnetic brake. Thereby, the rotating body can be attached and detached while the end of the housing on the output shaft side is fixed. Therefore, even if the radial force applied to the rotating shaft when the rotating body is attached to or detached from the apparatus body is transmitted to the output shaft end of the housing via the output shaft, the output shaft of the housing It is possible to suppress the end portion on the side from bending in the radial direction. Therefore, it is possible to suppress the end portion on the output shaft side of the housing from being greatly bent and damaged. Also, when a rotating body is mounted on the main body of the device, the energization control means stops energization of the electromagnetic brake, releases the electromagnetic adsorption of the attracted member to the electromagnetic brake, and fixes the end of the housing on the output shaft side Not be. Thus, when the rotating body is mounted on the apparatus main body, the end on the output shaft side of the housing can be bent and deformed in the radial direction according to the concentric error between the rotation shaft and the output shaft. Therefore, the rotating shaft and the output shaft are aligned, and the rotation unevenness of the rotating body can be reduced.
Further, according to the present embodiment, the housing and the internal gear are integrally configured, so that space saving and cost reduction can be achieved.
Further, according to the present embodiment, the position of the rotating shaft is restricted in the axial direction, so that the rotating shaft can be prevented from coming off to the front side or the rear side.
Further, according to this embodiment, since the planetary gear mechanism is configured in a plurality of stages in the axial direction in the housing, the reduction ratio can be increased and the load on the motor can be reduced. Can be miniaturized.
Further, according to the present embodiment, the photosensitive drum as the image carrier, the driving means for rotationally driving the photosensitive drum, and the rotational driving force from the driving means connected to the photosensitive drum and the driving means is photosensitive. In an image forming apparatus comprising a drive transmission means for transmitting to a body drum and an image forming means for forming an image on a photosensitive drum, the drive transmission device of the present invention is used as the drive transmission means, so that a rotating shaft Therefore, it is possible to obtain a centering effect by deformation of the internal gear against various errors in the connecting portion between the drum shaft and the cylindrical shaft that is the output shaft of the planetary gear mechanism. High-precision driving is possible, and damage to the planetary gear mechanism due to the attaching / detaching operation of the photosensitive drum can be suppressed.
According to this embodiment, the photosensitive drum can be inserted into and removed from the drum shaft, and the member to be attracted is electromagnetically attracted to the electromagnetic brake when the photosensitive drum is inserted into and removed from the drum shaft. The energization control means controls the energization to the electromagnetic brake in conjunction with the insertion / removal operation of the photosensitive drum so that the electromagnetic adsorption of the member to be adsorbed is released when the is attached to the drum shaft at a predetermined position. Thereby, it is possible to prevent the planetary gear mechanism from being damaged during the insertion / removal operation of the photosensitive drum.
Further, according to this embodiment, the photosensitive drum and at least one selected from a developing device as a developing unit, a charger as a charging unit, and a cleaning device as a cleaning unit are integrally configured, and an image forming apparatus A process cartridge that can be attached to and detached from the main body is provided. When the process cartridge is attached to or detached from the apparatus main body, the attracted member is electromagnetically attracted to the electromagnetic brake, and the process cartridge is attached to a predetermined position of the apparatus main body. The energization control means controls the energization of the electromagnetic brake in conjunction with the attachment / detachment operation of the process cartridge so that the electromagnetic adsorption of the attracted member is sometimes released. Thereby, it is possible to suppress the planetary gear mechanism from being damaged during the process cartridge attaching / detaching operation.
Further, according to the present embodiment, the positioning member for positioning the process cartridge with respect to the apparatus main body is provided in the process cartridge, and the energization control means includes a micro switch that is a switch for switching between energization and de-energization of the electromagnetic brake. The microswitch is operated in conjunction with the movement of the positioning member by the attaching / detaching operation of the process cartridge to switch between energization and non-energization of the electromagnetic brake. Accordingly, there is no need to provide a dedicated member for operating the micro switch 140 in conjunction with the attachment / detachment of the process cartridge, and accordingly, space saving and cost reduction in the apparatus can be achieved.

2 Charging Device 4 Cleaning Device 9 Developing Device 10 Intermediate Transfer Belt 12 First Sun Gear 13 Motor Fixing Flange 14 Internal Gear 15 First Planetary Gear 16 First Carrier 17 Second Sun Gear 18 Second Planetary Gear 19 Second Carrier 20 Cylindrical shaft 21 Spline portion 22 End cap 23a Roller 23b Roller 24 Internal gear fixing flange 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 30 Document table 32 Contact glass 33 First traveling body 34 Second traveling body 35 Connection Image lens 36 Sensor 40 Photosensitive drum 42 Paper feed roller 43 Paper bank 44 Paper feed cassette 45 Separating roller 46 Paper feed path 47 Conveying roller 49 Registration roller 50 Paper feed roller 51 Manual feed tray 52 Separating roller 53 Paper feed path 55 Switching claw 56 Discharge La 57 discharge tray 60 motor 70 drum shaft 81 first support roller 82 second support roller 83 third support roller 84 intermediate transfer belt cleaning device 85 image forming unit 86 tandem image forming unit 87 exposure device 88 secondary transfer device 89 second Next transfer belt 100 Copier main body 110 Main body front side plate 111 Face plate 112 Bearing 113 Pressure spring 114 Front drum flange 115 Rear drum flange 116 Serration coupling 117 Unit case 118 Positioning pin 119 Main body rear side plate 123a Bearing 123b Bearing 124 Color 125 Retaining ring 126 Stud 127 Drive side plate 128 Boss part 130 Electromagnetic brake 131 Output drive hub 132 Base 133 Electromagnetic coil 134 Field core 135 Friction pad 136 Armature 137 Spring disk 138 Color 140 Micro switch 141 Push button 142 Lever 150 Control circuit 200 Paper feed table 300 Scanner 400 Automatic document feeder

JP 2008-151868 A JP-A-4-331848

Claims (8)

A cylindrical housing, an internal gear provided in the housing, a sun gear disposed coaxially with the internal gear and rotated by a rotational driving force from a drive source, and the internal gear A plurality of planetary gears arranged in a circumferential direction and meshing with the sun gear and the internal gear, and a carrier rotatably supporting the planetary gear and coaxially rotatable with the sun gear and the internal gear. And a planetary gear mechanism comprising an output shaft provided on the carrier and outputting a rotational driving force,
In a drive transmission device that transmits a rotational driving force from a driving source to a rotating body that can be attached to and detached from the apparatus main body via a rotating shaft connected to the output shaft.
A fixing member for fixing an end of the housing opposite to the output shaft side;
An electromagnet provided in the apparatus body;
Energization control means for controlling energization to the electromagnet;
An adsorbed member that is provided at an end of the housing on the output shaft side so as to face the electromagnet, and is electromagnetically attracted and fixed to the electromagnet when the electromagnet is energized, and is released from electromagnetic attraction to the electromagnet when deenergized And
When the rotating body is attached to or detached from the apparatus main body, the energization control means energizes the electromagnet, and when the rotating body is mounted on the apparatus main body, the energization control means stops energization of the electromagnet. A drive transmission device characterized by that. The drive transmission device according to claim 1, wherein
A drive transmission device, wherein the housing and the internal gear are integrally formed. The drive transmission device according to claim 1 or 2,
A drive transmission device comprising a restricting means for restricting a position of the rotating shaft in the axial direction. The drive transmission device according to claim 1, 2 or 3,
The planetary gear mechanism includes a plurality of stages in the axial direction in the housing. An image carrier;
Drive means for rotationally driving the image carrier;
Drive transmission means coupled to the image carrier and the drive means for transmitting a rotational driving force from the drive means to the image carrier;
In an image forming apparatus comprising image forming means for forming an image on the image carrier,
An image forming apparatus using the drive transmission device according to claim 1, 2, 3, or 4 as the drive transmission means. The image forming apparatus according to claim 5.
The image carrier can be inserted and removed with respect to the rotating shaft,
The attracted member is electromagnetically attracted to the electromagnet when the rotating body is inserted into and removed from the rotating shaft, and the electromagnetic wave of the attracted member is attached when the image carrier is mounted at a predetermined position of the rotating shaft. An image forming apparatus, wherein the energization control unit controls energization to the electromagnet in conjunction with an insertion / removal operation of the rotating body so that the suction is released. The image forming apparatus according to claim 5 or 6,
The image carrier and at least one selected from a developing unit, a charging unit, and a cleaning unit are integrally configured, and a process cartridge that can be attached to and detached from the image forming apparatus main body is provided.
When the process cartridge is attached to or detached from the apparatus main body, the attracted member is electromagnetically attracted to the electromagnet, and when the process cartridge is mounted at a predetermined position of the apparatus main body, the electromagnetic attracting of the attracted member is released. As described above, the energization control means controls the energization of the electromagnet in conjunction with the process cartridge attaching / detaching operation. The image forming apparatus according to claim 7.
A positioning member for positioning the process cartridge with respect to the apparatus main body is provided in the process cartridge;
The energization control means has a switch for switching between energization and de-energization of the electromagnet,
An image forming apparatus, wherein the switch is operated in conjunction with the movement of the positioning member by the attaching / detaching operation of the process cartridge to switch between energization and non-energization of the electromagnet.

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