Patent Application
20180017926
Field of the Invention
The present invention relates to a drive transmission apparatus configured to transmit driving force from a driving source to an operation part, and an image forming apparatus equipped with the drive transmission apparatus.
Description of the Related Art
Heretofore, in the field of image forming apparatuses, a configuration adopting a swing gear mechanism with the aim to transmit driving force from a driving source such as a motor has been known. Japanese Unexamined Patent Application Publication No. 2004-060666 discloses a drive transmission apparatus in which driving force is transmitted from a main body unit equipped with a driving motor via two swing gears to an opening/closing unit that can be opened and closed with respect to the main body unit.
According to this configuration, each swing gear, arranged in the main body unit and meshed with a drive gear driven by a driving motor, is supported by a support arm swingable with respect to the drive gear. The swing gear is arranged to be meshed with a driven gear arranged in an opening/closing unit in the state where the opening/closing unit is closed, such that change in distance between axes of the drive gear and driven gear caused by displacement of the opening/closing unit in a closed state is absorbed.
Now, according to such a configuration including a swing gear mechanism as the above described document, unlike normal gears having a fixed axial position, the support arm supporting the swing gear must be swingable in the assembled state. Therefore, the assembling operation should be carried out in a state where the drive gear, the swing gear and the support arm are positioned such that the swing gear is meshed with the drive gear, and that the support arm is swingable after being assembled.
However, if such assembling operation is performed manually, the operation of mounting the support arm swingably with respect to the drive gear is carried out while holding a plurality of members including the swing gear and the support arm, and this causes complication of the assembling operation. Even if components are temporarily assembled before carrying out the assembling operation with the aim to reduce workload of the assembling operation, the temporal assemble process causes the number of steps for manufacturing the entire apparatus to be increased.
The present invention provides a drive transmission apparatus capable of reducing the workload during assembly and improving efficiency of the assembly operation, and an image forming apparatus equipped with the same.
According to one aspect of the present invention, a drive transmission apparatus includes a first input gear configured to be driven by driving force from a driving source, a first swing gear configured to be rotated by driving force from the first input gear, a supporting portion arranged on an axis of the first input gear, and a first swing member configured to swing the first swing gear and including a first engagement portion configured to be engaged pivotably with the supporting portion and a first retaining portion configured to retain the first swing gear in a rotatable manner. The first engagement portion is attached to and detached from the supporting portion if the first swing member is moved in a radial direction with respect to an axis of the first input gear.
According to another aspect of the present invention, a drive transmission apparatus includes an apparatus body, a driving source arranged in the apparatus body and configured to output rotation in a first direction and rotation in a second direction opposite to the first direction, a conveyance unit including a conveyance member configured to convey a sheet, a first output gear connected to the conveyance member, a movement mechanism configured to move the conveyance unit relatively with respect to the apparatus body by the movement mechanism, and a second output gear connected to the movement mechanism, and a drive transmission apparatus configured to transmit driving force from the driving source to the conveyance unit. The drive transmission apparatus includes a first input gear configured to be driven by the driving source if the driving source outputs rotation in the first direction, a second input gear arranged coaxially with the first input gear and configured to be driven by the driving source if the driving source outputs rotation in the second direction, a first swing gear meshed with the first input gear and the first output gear, a second swing gear meshed with the second input gear and the second output gear, a supporting portion arranged on an axis of the first and second input gears, a first swing member configured to swing the first swing gear, and a second swing member configured to swing the second swing gear. The first swing member includes a first engagement portion configured to be engaged pivotably with the supporting portion, and a first retaining portion configured to retain the first swing gear in a rotatable manner. The first engagement portion is attached to and detached from the supporting portion if the first swing member is moved in a radial direction with respect to the axis of the first and second input gears. The second swing member includes a second engagement portion configured to be engaged with the supporting portion and a second retaining portion configured to retain the second swing gear in a rotatable manner. The second engagement portion is attached to and detached from the supporting portion if the second swing member is moved in a radial direction with respect to the axis of the first and second input gears.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Now, an image forming apparatus according to the present disclosure will be described with reference to the drawings. An image forming apparatus 1 illustrated in
A plurality of sheet feeding units 10a and 10b are provided on an apparatus body 2 of the image forming apparatus 1. The respective sheet feeding units 10a and 10b are equipped with lift-up units 11a and 11b that can be lifted and lowered while supporting a sheet S, and feed rollers 12a and 12b feeding the sheets S supported on the lift-up units 11a and 11b. The sheets S sent out by the feed rollers 12a and 12b are separated one sheet at a time by separation rollers 13a and 13b, and conveyed via drawing roller pairs 20a and 20b toward a registration unit 30. The sheet S fed from the sheet feeding unit 10b arranged on the left side in the drawing is conveyed via a duplex conveyance unit 80 described later.
Simultaneously as the above-described conveyance process of the sheet S, an imaging operation, i.e., image forming process, of toner image is executed in image forming units 90, 96, 97 and 98. The image forming units 90, 96, 97 and 98, which are examples of the image forming units, respectively form toner images of yellow, magenta, cyan and black colors. The configuration of these image forming units are similar, excluding the color of the toner used for developing the image, so in the following description, the yellow image forming unit 90 will be described as an example.
The image forming unit 90 is an electro-photographic image forming unit equipped with a photosensitive drum 91 serving as a photoconductor. An exposing unit 93, a developing apparatus 92, a cleaner 95 and so on are arranged around the photosensitive drum 91. In a state where image forming operation is started, a surface of the photosensitive drum 91 is charged uniformly by a charger not shown along with the rotation of the photosensitive drum 91. The exposing unit 93 modulates and outputs laser beams based on image information, and scans the photosensitive drum 91 using a mirror 94 constituting a scanning optical system, to thereby create an electrostatic latent image on the drum surface. The developing apparatus supplies charged toner to the photosensitive drum 91, and forms, i.e., develops the electrostatic latent image as a toner image.
An intermediate transfer belt 40 serving as an intermediate transfer member is formed of an endless belt-shaped film, and the belt is wound around a drive roller 42, a tension roller 41, and a secondary transfer inner roller 43. The intermediate transfer belt 40 is driven to rotate by the drive roller 42 in a predetermined direction, illustrated by arrow T1. Primary transfer rollers 45 are arranged at a position opposing to the photosensitive drums 91 of the respective image forming units 90, 96, 97 and 98 at an inner circumference side of the intermediate transfer belt 40. By applying bias voltage to the primary transfer rollers 45, the toner images formed in the image forming units 90, 96, 97 and 98 are subjected to primary transfer to the intermediate transfer belt 40 such that the toner images of the respective colors are superposed. Attached substances such as transfer residual toner remaining on the photosensitive drum 91 without being transferred to the intermediate transfer belt 40 are removed by the cleaner 95.
A secondary transfer roller 44 serving as a transfer member configured to transfer a toner image onto a sheet is in pressure contact with the secondary transfer inner roller 43 and interposing the intermediate transfer belt 40, and forms a secondary transfer portion serving as a nip portion with the intermediate transfer belt 40. After correcting skew feed of the sheet S, the above-described registration unit 30 transfers the sheet S to the secondary transfer portion, along with the advancement of the image forming operation of the toner image. In a state where bias voltage is applied to the secondary transfer roller 44, the full-color toner image formed on the intermediate transfer belt 40 is collectively subjected to secondary transfer to the sheet S. The attached substances such as the transfer residual toner remaining on the intermediate transfer belt 40 without being transferred to the sheet S is removed by a cleaner 46.
The sheet S to which the toner image has been transferred at the secondary transfer portion is conveyed by a pre-fixing conveyance unit 51 described in detail later toward a fixing unit 52. The fixing unit 52, which is one example of a fixing unit, includes a fixing roller pair 54 serving as a pair of rotary fixing members configured to nip and convey a sheet, and a heat source such as a halogen heater. The fixing unit applies heat and pressure to the sheet S at the nip portion of the fixing roller pair 54 to fix the toner image onto the sheet. The configuration described later can be applied in a state where the sheet S is conveyed via a rotary member pair in which one side or both sides of the members constituting the nip portion is/are formed of a belt member, in place of the fixing roller pair 54.
In the case of single surface printing, the sheet S having passed through the fixing unit 52 is guided to a branch conveyance unit 60, and discharged onto a sheet discharge tray 61 provided outside the apparatus body 2. On the other hand, in the case of duplex printing, the sheet S having passed through the fixing unit 52 is guided to a reverse conveyance unit 70 by the branch conveyance unit 60. The sheet S is subjected to switch-back at the reverse conveyance unit 70, and conveyed by the duplex conveyance unit 80 toward the registration unit 30. Then, the sheet S formed an image on a second surface through a similar process as the first surface described above is guided by the branch conveyance unit 60 and discharged onto the sheet discharge tray 61.
Next, the configuration of the pre-fixing conveyance unit 51 will be described. The pre-fixing conveyance unit 51 is composed of a conveyance portion 51b serving as a conveyance unit configured to convey the sheet S, and a base portion 51a serving as a driving unit described later.
As illustrated in
As illustrated in
The ventilating duct portion 106c is connected to a fixed duct 104 fixed to a side panel 2a through an opening portion formed on the side panel 2a. The side panel 2a is fixed to the apparatus body 2, and the opening of the side panel 2a and the ventilating duct portion 106c are connected airtightly by a sponge-like seal member 110. Further, a suction fan 105 discharging air to an outer side of the fixed duct 104 is arranged on the end portion of the fixed duct 104 as a suction apparatus configured to take in air (refer to
According to this configuration, in a state where the suction fan 105 is operated, air is taken in through air holes of the conveyor belt 101, as illustrated in
Next, a conveyance path of the sheet S in the vicinity of the pre-fixing conveyance unit 51 will be described. As illustrated in
The sheet conveyance path between the transfer nip portion N1 and the fixing nip portion N2 is formed to bend downward. That is, a conveyance direction of the sheet S in the transfer nip portion N1 and a conveyance direction of the sheet S in the fixing nip portion N2 are designed to intersect at an offset position on one side, that is, lower side in the drawing, with respect to a straight line L0 connecting the nip portions N1 and N2. The pre-fixing conveyance unit 51 is arranged such that the conveyor belt 101 is separated by distance ΔD toward an outer side of the curve of the sheet conveyance path from the straight line L0. Further, the transfer exit guide 50 and the fixing entrance guide 53 are arranged such that the upper surface constituting a guide surface is inclined downward toward the conveyor belt 101.
According to this configuration, the sheet S is conveyed in a curved state near the pre-fixing conveyance unit 51. Therefore, even if there is a difference in conveyance speed of the sheet S in the transfer nip portion N1 and the fixing nip portion N2, the speed difference is absorbed by the bending of the sheet S. Thereby, problems that occur by the difference in conveyance speed, such as image defects caused by having tension applied on the sheet S, can be prevented. Further, retention force of the sheet S by the conveyor belt 101 is set to be smaller than a retention force of the sheet by the transfer nip portion N1 and the fixing nip portion N2 retaining the sheet S by the nip pressure of the roller pair. Therefore, even in a state where there is a difference in conveyance speeds between the transfer nip portion N1 or the fixing nip portion N2 and the conveyor belt 101, it becomes possible to prevent the toner image from being disarranged by the slipping of the conveyor belt 101 on a rear surface of the sheet S at the nip portion.
If a sheet S such as cardboard having a high stiffness, that is, high basis weight, is conveyed, the sheet is conveyed in a state where the bending is smaller than the sheet S having a low stiffness, due to its own stiffness. In this case, the conveyor belt 101 may be separated from the sheet S, and conveyance error of the sheet S may occur near the pre-fixing conveyance unit 51.
Therefore, according to the present embodiment, as illustrated in
Next, a drive configuration of the pre-fixing conveyance unit 51 capable of conveying the sheet S and capable of moving with respect to the apparatus body 2 will be described. As illustrated in
The driving unit 51c serves as a drive transmission apparatus configured to transmit driving force output from a motor 123 serving as a driving source to the conveyance portion 51b. As illustrated in
As illustrated in
The rotation of the pinion gear 124 is reduced by a step gear 125 supported by the support plate 122, and transmitted to an idler gear 126. The idler gear 126 is supported on a drive shaft 127 in a manner incapable of relative rotation, and the drive shaft 127 has both axial end portions supported rotatably with respect to the support plate 122 by a shaft holder 128.
A conveyance one-way gear 129 and an elevation one-way gear 130 relatively rotatable with respect to the drive shaft 127 are arranged on one side and the other side of the idler gear 126 in the axial direction. The one-way gears 129 and 130 are examples of input gears driven by driving force from the driving source. One-way clutches 129a and 130a (refer to
As illustrated in
As illustrated in
Meanwhile, the elevation drive gear 117 is mounted in a manner incapable of relative rotation with respect to the drive pulley shaft 111. In a state where the drive pulley shaft 111 is rotated, elevation output gears 118 and 118 mounted on both end portions in the axial direction of the drive pulley shaft 111 rotate. The respective elevation output gears 118 and 118 rotate the cam gears 119 and 119 connected via two idler gears 120 and 120. The respective cam gears 119 serving as an example of a movement mechanism moving the conveyance unit include a gear portion 119a meshed with the idler gear 120 and a cam portion 119b being in contact with a cam holder 136 (refer to
Further, as illustrated in
The abutment portion 113 is composed of a cylindrical member loosely-fit to the drive pulley shaft 111. The contact plate 131b serving as a first contact portion is formed integrally with the conveyance swing arm 131, and the contact plate 133b serving as a second contact portion is formed integrally with the elevation swing arm 133. The respective contact plates 131b and 133b have a circular arc-shaped outer circumference portion centered around a rotational axis of the corresponding swing gear 132 or 134. The components are configured so that a sum of a radius of the abutment portion 113 and a radius of the outer circumference portion of the respective contact plates 131b and 133b is equal to a sum of pitch radii of the corresponding swing gears 132 and 134 and the drive gears 116 and 117.
A swing spring 135 serving as an urging member configured to urge the arms toward each other is stretched between the conveyance swing arm 131 and the elevation swing arm 133, as illustrated in
As described, the pre-fixing conveyance unit 51 is equipped with two drive transmission systems configured to transmit rotation output from the motor 123 to the idler gear 126 to operation parts (101, 119) of the conveyance portion 51b. A conveyance system for driving the conveyor belt 101 includes the conveyance one-way gear 129, the conveyance swing gear 132, the conveyance drive gear 116 and the drive pulley 102. Further, an elevation system to drive the cam gears 119 includes the elevation one-way gear 130, the elevation swing gear 134, the elevation drive gear 117, the drive pulley shaft 111, the elevation output gears 118 and the idler gears 120. In the present embodiment, the rotational axis of the one-way gears 129 and 130 and the rotational axis of the drive gears 116 and 117 are common among the conveyance system and the elevation system, such that the apparatus can be downsized.
The conveyance one-way gear 129 and the elevation one-way gear 130 respectively serve as the first and second input gears, and the conveyance drive gear 116 and the elevation drive gear 117 respectively serve as the first and second output gears. Further, the conveyance swing arm 131 and the elevation swing arm 133 respectively serve as the first and second swing members, and the conveyance swing gear 132 and the elevation swing gear 134 respectively serve as the first and second swing gears. Here, a first input gear represents one input gear in a drive transmission apparatus including at least one input gear, and a second input gear represents one input gear other than the first input gear in the drive transmission apparatus including at least one input gear in addition to the first input gear. Therefore, in a configuration where the cam gear 119 is driven by a common configuration as the elevation system described above, while the conveyor belt 101 is driven by a configuration that differs from the mechanism according to the above-mentioned conveyance system, the elevation one-way gear 130 serves as the first input gear. The same applies for first and second output gears, first and second swing members, and components associated therewith including ordinal numbers.
Next, an operation of the pre-fixing conveyance unit 51 will be described with reference to
If the motor 123 is rotated in the normal rotation direction, the conveyance one-way gear 129 out of the one-way gears 129 and 130 is rotated by the action of the one-way clutch. Then, rotation is transmitted via the conveyance swing gear 132 and the conveyance drive gear 116 to the drive pulley 102, and the conveyor belt 101 is driven by the drive pulley 102. In this case the respective members of the elevation system do not receive input of the driving force, and the conveyance portion 51b is retained at a fixed height.
If the motor 123 is rotated in the reverse rotation direction, the elevation one-way gear 130 out of the one-way gears 129 and 130 is rotated by the action of the one-way clutch. Then, rotation is transmitted via the elevation swing gear 134 and the elevation drive gear 116 to the drive pulley shaft 111. The rotation of the drive pulley shaft 111 is distributed to four cam gears 119 by the action of the elevation output gears 118 and the idler gears 120 (not shown), and along with the rotation of the cam portion 119b, the conveyance portion 51b moves in the vertical direction with respect to the frame 121. The shape of the cam portions 119b is set so that the conveyance portion 51b moves from one position to another position between the upper direction and the lower direction while the cam gears 119 rotate for 180 degrees, for example. While the motor 123 rotates in the reverse rotation direction, the respective members of the conveyance system do not receive input of driving force, and input of driving force to the conveyor belt 101 is stopped.
Next, a configuration for assembling a driving unit 51c including two swing arms 131 and 133 to the apparatus body 2 will be described with reference to
As illustrated in
The detailed configuration of the swing arms 131 and 133 and the assembling process thereof will be described with reference to
As illustrated in
Meanwhile, the elevation swing arm 133 includes, in addition to a retaining portion 133c configured to retain the elevation swing gear 134 rotatably, a cutout portion 133a having an end portion of the arm cut out, the cutout portion 133a serving as an engagement portion configured to be attached to and detached from, i.e., engaged with and disengaged from, the shaft holder 128. The cutout portion 133a includes a circular arc-shaped inner contact portion a1 formed along an inscribed circle having an approximately same diameter as the outer contact portion 128b of the shaft holder 128 and an opening a2 formed to open outward from the inner contact portion a1 with a width smaller than the diameter of the inscribed circle.
Planar portions 128a and 128a of the shaft holder 128 is formed to have a width equal to or smaller than an opening width of the opening portion a2 as seen from the assembling angle θa. That is, the respective planar portions 128a are an example of a small width portion formed to have a smaller width than the outer diameter of the outer contact portion 128b. Further, the outer contact portion 128b having a greater outer diameter than the small diameter portion serves as a slide contact surface capable of being in slide contact with the inner contact portion a1 of the cutout portion 133a in a state where the elevation swing arm 133 is assembled.
The operator inserts the elevation swing arm 133 with the elevation swing gear 134 assembled thereto along the assembling angle θa while opposing the opening a2 of the cutout portion 133a to the planar portions 128a and 128a of the shaft holder 128. Then, as illustrated in
Further, if the elevation swing arm 133 is pivoted from the assembling angle θa, as illustrated in
Meanwhile, as illustrated in
In a state where the elevation swing arm 133 is locked to the shaft holder 128, the operator inserts the conveyance swing arm 131 to which the conveyance swing gear 132 has been assembled along the assembling angle θa while opposing the opening portion a2 of the cutout portion 131a to the planar portions 128a and 128a. Then, as illustrated in
Next, an assembling process of the swing spring 135 connecting the two swing arms 131 and 133 will be described. As illustrated in
The operator attaches the swing spring 135 to the supporting projections 131e and 133e in a state where the conveyance swing arm 131 and the elevation swing arm 133 are mounted to the shaft holder 128. Then, as illustrated in
Next, a process of mounting the driving unit 51c to the frame 121 will be described. As illustrated in
If the operator moves the driving unit 51c downward toward the frame 121, as illustrated in
Further, along with the pivoting of the conveyance swing arm 131, the elevation swing arm 133 is also pivoted in the same direction as the conveyance swing arm 131 against gravity by the urging force of the swing spring 135. The size of pivoting angle of the frame projection 121a is set such that angles α0 and β0 of the respective swing arms 131 and 133 are set to different angles as the assembling angle θa in a state where the driving unit 51c is in contact with the frame 121. Then, the base portion 51a is formed by fixing the support plate 122 to the frame 12.
Finally, a process of mounting the conveyance portion 51b to the base portion 51a will be described. As described, the conveyance portion 51b serving as a conveyance unit is mounted from an upper side to the base portion 51a (refer to
As illustrated in
In a state where assembly of the conveyance portion 51b is completed, the contact plates 131b and 133b are pressed toward the abutment portion 113 by the urging force of the swing spring 135, such that the state of contact of the respective contact plates 131b and 133b and the abutment portion 113 are maintained. Therefore, while the conveyance portion 51b moves up and down between the upper position and the lower position, the conveyance swing arm 131 swings between an angle al and an angle α2, i.e., within a first swing range, and the elevation swing arm 133 swings between an angle β1 and an angle β2, i.e., within a second swing range. Thereby, in a state where the conveyance portion 51b moves between a first position, i.e., upper position, and a second position, i.e., lower position, the respective swing gears 132 and 134 swing in a state being meshed with the corresponding one-way gears 129 and 130 and drive gears 116 and 117.
As illustrated in
From the viewpoint of ensuring an effect to prevent the swing arms 131 and 133 from falling, a difference of angle between the assembling angle θa and the swing range should preferably be as close to 90 degrees as possible, as long as the ease of assembling operation is not deteriorated. In the present embodiment, even in a state where the respective swing arms 131 and 133 are positioned closest to the assembling angle θa, i.e., positioned at the angles of α2 and β2, the difference with the assembling angle θa is maintained to be 45 degrees or greater.
Further, in case of maintenance, for example, the swing arms 131 and 133 can be detached from the shaft holder 128 by performing the above-described process in the opposite order. That is, the respective swing arms 131 and 133 should be moved to the assembling angle θa after removing the driving unit 51c from the frame 121 and then removing the driving unit 51c. Thereby, the cutout portions 131a and 133a are made detachable from the shaft holder 128, and the swing arms 131 and 133 can be pulled out along the assembling angle θa.
As described, according to the present embodiment (first embodiment of the present disclosure), the swing ranges (α1 to α2, β1 to β2) of the two swing arms 131 and 133 corresponding to the range of elevation operation of the conveyance portion 51b are set so as not to include the assembling angle θa, which is the predetermined position. That is, the shapes of the cutout portions 131a and 133a and the shaft holder 128 are set so that in the assembling process, the respective swing arms 131 and 133 are enabled to be assembled along an angle (θa) out of the swing range of the operation after the assembly. According to this configuration, it becomes possible to assemble the swing gears 132 and 134 and the swing arms 131 and 133 by a simple operation of holding the swing arms 131 and 133 and moving the arms in the radial direction toward the shaft holder 128 serving as the swing shaft.
As a first comparative example with respect to the first embodiment, it is considerable to design the shaft holder in a cylindrical shape, and providing a circular engagement hole to the swing arm for engagement with the shaft holder. However, according to such configuration, it is considered that one can no longer assemble the swing arm by movement in a radial direction. Then, the number of steps or the complexity of the assembling operation may be increased, since it is necessary to retain the swing arm at a position where the swing gear and the corresponding input gear are meshed with each other, and further hold the shaft holder and engage the shaft holder to the engagement hole on the swing arm. Further, even if such a configuration is adopted that a part of the members are temporarily attached in order to reduce the workload, the increase of the number of steps for removing the temporarily attached members or the increase of operation costs caused by using a holding or fastening member to temporary attach the members are concerned.
Further, a second comparative example includes designing the shaft holder in a cylindrical shape and providing a U-shaped cutout portion to the swing arm, to enable assembly of the swing arm by the inserting operation of the arm in the radial direction. In this case, since the cutout portion and the shaft holder are capable of performing relative movement in the radial direction, regardless of the angle of the swing arm, a mechanism to prevent the swing arm from falling is required. However, if the number of components is increased compared to the present embodiment by providing such a fall prevention mechanism, there is fear that the number of steps of the assembling operation or the component costs are increased thereby.
In contrast, according to the present embodiment, a configuration is realized by devising the shapes of the cutout portions 131a and 133a and the shaft holder 128, such that assembly to the shaft holder 128 is enabled at a position along the assembling angle θa, and detachment from the shaft holder 128 is prevented at a position within the swing range after the assembly. Therefore, the number of steps of the assembling operation can be reduced without providing a complex additional mechanism, compared to the first and second comparative examples.
Specifically, according to the present embodiment, in a configuration where two input gears (129, 130) are arranged on a common axis, similar cutout portions 131a and 133a are formed on swing arms 131 and 133 retaining the swing gears 132 and 134 meshed with the respective input gears. Therefore, the gear trains can be made compact, and the workload related to assembling the plurality of swing arms 131 and 133 can be reduced. Further, since the respective swing arms 131 and 133 can be inserted from the same direction to a common shaft holder 128, the assembling operation can be comprehended instinctively, and the configuration can contribute to reducing the workload. The present technique can be applied to only one of the two swing arms 131 and 133, and in a drive transmission apparatus having one set of swing gear and swing arm, the present technique can be applied to the swing gear and the swing arm.
The actual shapes of the engagement portion provided on the swing member, such as the swing arm, and the supporting portion supported on the apparatus body, are not restricted to those described above. For example, it is possible to switch the configurations of the shaft holder 128 and the cutout portions 131a and 133a of the present embodiment, such that the engagement portion has a two-side cutaway shape similar to the shaft holder 128, and the supporting portion has an inner contact portion and an opening portion similar to the cutout portions 131a and 133a. According to this configuration, an effect similar to the present embodiment can be realized.
Further, a one-side cutaway shape in which a cylinder is cut away by one plane (D-cut shape) can be adopted instead of the two-side cutaway shape in which the cylinder is cut by two planes, as in the case of the shaft holder 128.
Next, a driving unit 51d according to a second embodiment will be described with reference to
As illustrated in
As illustrated in
Also according to the present embodiment, similar to the first embodiment, a direction of insertion, i.e., assembling angle θa, of the swing arms 131 and 133 with respect to the drive shaft 227 is configured to be out of the swing ranges of the swing arms 131 and 133 corresponding to the elevation operation range of the conveyance portion 51b. Accordingly, even if the configuration of the present embodiment is adopted, the swing gears 132 and 134 and the swing arms 131 and 133 can be assembled by a simple operation of holding the swing arms 131 and 133 and moving the arms in the radial direction toward the shaft holder 128 serving as the swing shaft.
In the first and second embodiments described above, an example of applying the configuration of the drive transmission apparatus according to the present embodiment as the driving unit 51c of the pre-fixing conveyance unit 51 has been described, but the present technique can also be applied to a drive transmission apparatus of an image forming apparatus or an apparatus used for other purposes. For example, the present technique can be preferably adopted to a sheet conveyance unit other than the pre-fixing conveyance unit of an image forming apparatus, as a driving configuration of a unit movable with respect to the apparatus body.
In the above embodiments, an intermediate transfer-type image forming apparatus 1 utilizing an intermediate transfer belt 40 has been described, but the configurations described above can also be applied to a driving unit of a pre-fixing conveyance unit in a direct transfer type apparatus in which toner image is transferred directly from the photosensitive drum to the sheet. That is, the present technique can be applied to a conveyance unit configured to convey a sheet to a fixing unit from a transfer portion in which a toner image is transferred to a sheet from an image bearing member such as a photoconductor or an intermediate transfer member. Further, the image forming apparatus is not restricted to an electro-photographic system, and may include an apparatus including a known image forming method such as an inkjet system.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2016-137493, filed on Jul. 12, 2016, which is hereby incorporated by reference wherein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-137493 | Jul 2016 | JP | national |
