Drive transmission device and image forming apparatus

Abstract

To provide a drive transmission device that can prevent lubricant from entering an electromagnetic clutch and has high operational reliability.SOLUTION: A drive transmission device is removably attached to a main body device having a body to be driven mounted therein to which a driving force is transmitted, and comprises: a rotary shaft member 114 that rotates upon receiving the driving force from a driving source; a bearing member 140 into which the rotary shaft member 114 is inserted; two holding members 102, 103 that are arranged opposite to each other at an interval and each have a through hole formed therein; and an electromagnetic clutch member 108 that is disposed between the two holding members. The rotary shaft member 114 is inserted into the through hole of one holding member 103 at one end in an axial direction with the bearing member 140 therebetween, and inserted into the through hole of the other holding member 102 at the other end. The rotary shaft member 114 and the bearing member 140 have an engaging structure in which the members are engaged with each other along a circumferential direction of a rotation axis.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a drive transmission device and an image forming apparatus.

Background Art

[0002] As a drive transmission device mounted on an image forming apparatus or the like, there is known a device that is configured to be detachable from a main body device having two opposing members that face each other while forming a gap, a gear that rotates within the gap, and a driven body to which a driving force is to be transmitted (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a drive transmission device that realizes miniaturization and quality improvement by arranging a plurality of rotating shaft members integrated with drive components so as to penetrate both a metal plate and a mold cover, and positioning the metal plate and the mold cover by the rotating shaft members and stud shafts.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a drive transmission device that does not provide a bearing member at a sliding portion of a rotating shaft member, such as the configuration of Patent Document 1, improvement in wear resistance of the sliding portion and reduction of noise are required. To achieve these requirements, for example, a lubricant such as grease is applied to the outer peripheral surface of the rotating shaft member.

[0005] However, the applied lubricant may flow out along the rotating shaft over time and adhere to other members or penetrate into the interior of other members. In particular, in an aspect provided with an electromagnetic clutch, a lubricant containing oil may affect the operation of the electromagnetic clutch, possibly causing a malfunction.

[0006] Therefore, an object of the present invention is to provide a drive transmission device that can prevent the intrusion of lubricant into an electromagnetic clutch and has high operation reliability.

Means for Solving the Problems

[0007] To solve the above problems, the drive transmission device of the present invention is a drive transmission device that is detachably attached to a main body device on which a driven body to which driving force is to be transmitted is mounted, and comprises a rotating shaft member that rotates in response to a driving force from a drive source, a bearing member through which the rotating shaft member is inserted, two holding members having through holes formed thereon and spaced apart and facing each other, and an electromagnetic clutch member disposed between the two holding members, wherein one end of the rotating shaft member in the axial direction is inserted through the through hole of one of the holding members via the bearing member, and the other end is inserted through the through hole of the other holding member, and the rotating shaft member and the bearing member have an engagement structure in which they engage with each other along the circumferential direction of the rotating shaft. [Effects of the Invention]

[0008] According to the present invention, it is possible to prevent lubricant from entering the electromagnetic clutch, and to provide a drive transmission device with high operational reliability. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of an image forming apparatus according to one embodiment of the present invention. [Figure 2] Figure 1 is an explanatory diagram of the imaging unit included in the image forming apparatus. [Figure 3] This is a perspective view showing an example of a drive transmission device. [Figure 4] Figure 3 is a perspective view of the drive transmission device from the reverse direction. [Figure 5] This is a perspective view showing an example of an electromagnetic clutch. [Figure 6] This is a perspective view showing the rotating shaft member, bearing member, and electromagnetic clutch. [Figure 7] This is a schematic side view showing an example of a drive transmission device. [Figure 8] This is a cross-sectional view of a key part of a drive transmission device according to one embodiment of the present invention. [Figure 9] This is an enlarged diagram illustrating the area enclosed by the dashed line in Figure 8. [Figure 10](A) is a perspective view showing an example of a rotating shaft member of a drive transmission device according to the present invention, and (B) is a conventional example. [Figure 11] (A) is a perspective view showing an example of a bearing member of a drive transmission device according to the present invention, and (B) is a conventional example. [Modes for carrying out the invention]

[0010] The drive transmission device and image forming apparatus of the present invention will be described below with reference to the drawings. It should be noted that the present invention is not limited to the embodiments shown below, and can be modified, added, altered, or deleted to the extent that a person skilled in the art can conceive of it. Any embodiment that achieves the function and effect of the present invention is included within the scope of the present invention.

[0011] [Image forming apparatus] The image forming apparatus according to the present invention is equipped with a drive transmission device according to the present invention, which will be described later, as a drive transmission means for driving a driven object. Figure 1 is a schematic diagram of an electrophotographic printer as an image forming apparatus according to one embodiment of the present invention.

[0012] The image forming apparatus 100 shown in Figure 1 is equipped with four imaging units 26K, 26C, 26M, and 26Y for creating toner images of black (K), cyan (C), magenta (M), and yellow (Y). Figure 2 is an enlarged explanatory diagram showing one of the four imaging units 26K, 26C, 26M, and 26Y. In this figure, the subscripts K, C, M, and Y that are usually added to the end of the symbols attached to each component have been omitted.

[0013] In the image forming unit 26, the surface of the photoreceptor 24 as a latent image carrier that is rotationally driven clockwise in the figure is uniformly charged by the charging device 25. The surface of the uniformly charged photoreceptor 24 is exposed and scanned by the laser beam L irradiated by the light writing unit 27 to carry an electrostatic latent image for each color. This electrostatic latent image is developed into a toner image by the developing unit 23 using toner. Then, this toner image is primarily transferred onto the intermediate transfer belt 22.

[0014] After passing through the primary transfer process, the surface of the photoreceptor 24 is cleaned of residual transferred toner by the photoreceptor cleaning device 83, and the residual charge is removed by the charge eliminating device in preparation for the next image formation.

[0015] The illustrated developing unit 23 has a vertically long hopper portion 86 that houses toner as a developer, and a developing portion 87. Inside the hopper portion 86, an agitator 88, a toner supply roller 80, etc. that are rotationally driven by driving means are disposed. Inside the developing portion 87 of the developing unit 23, a developing roller 81, a thinning blade 82, etc. are disposed.

[0016] As shown in FIG. 2, above the image forming units 26K, 26C, 26M, 26Y in the vertical direction, a light writing unit 27 as a latent image writing device is disposed.

[0017] Also, below the image forming units 26K, 26C, 26M, 26Y in the vertical direction, a transfer unit 75 is disposed. The transfer unit 75 includes an intermediate transfer belt 22, a driving roller 76, a tension roller 20, four primary transfer rollers 74K, 74C, 74M, 74Y, a secondary transfer roller 21, a belt cleaning device 71, a cleaning backup roller 72, etc.

[0018] Below the transfer unit 75 in the vertical direction, a paper feed cassette 41 is disposed. This paper feed cassette 41 abuts the paper feed roller 42 against the top recording paper of the paper stack, and by rotating this in the counterclockwise direction in the figure at a predetermined timing, the recording paper is sent out toward the paper feed path.

[0019] Near the end of the paper feed path, a resist roller pair 43 composed of two resist rollers is disposed. This resist roller pair 43 feeds out the recording paper toward the secondary transfer nip at a timing that can synchronize the recording paper with the four-color toner image on the intermediate transfer belt 22 within the above-described secondary transfer nip. Note that a relay roller 44 is also provided in the paper feed path.

[0020] The four-color toner image on the intermediate transfer belt 22 that is adhered to the recording paper at the secondary transfer nip is collectively secondarily transferred onto the recording paper under the influence of the secondary transfer electric field and nip pressure. The recording paper having a full-color toner image formed on its surface in this way is separated from the secondary transfer roller 21 and the intermediate transfer belt 22 by the amount of curvature when passing through the secondary transfer nip, and is fed into a fixing device 40 as a fixing means.

[0021] The fixing device 40 fixes the unfixed toner image of the fed recording paper to the recording paper by a fixing roller 45 containing a heat source 45a such as a halogen lamp and a pressure roller 47. The recording paper discharged from the fixing device 40 is sent to a paper discharge roller pair 90.

[0022] When the single-sided print mode is selected, the recording paper sandwiched between the paper discharge nips of the paper discharge roller pair 90 is discharged as it is to the outside of the machine by the forward rotation drive of the paper discharge roller pair 90, and is stacked on a stack portion 56 provided on the upper surface of the upper cover of the housing.

[0023] When the double-sided print mode is selected, the recording paper sandwiched between the paper discharge nips of the paper discharge roller pair 90 is sent toward the outside of the machine to a certain extent, and then is returned into the machine by the reverse rotation drive of the paper discharge roller pair 90 and enters the reverse conveyance path 91. Then, after being turned upside down through the double-sided conveyance nip of the double-sided conveyance roller pair 92, it re-enters the paper feed path and is re-conveyed to the resist roller pair 43. Thereafter, it is sent to the secondary transfer nip at a predetermined timing, and after the toner image is secondarily transferred onto the other side as well, it is discharged to the outside of the machine through the fixing device 40 and the paper discharge roller pair 90 and is stacked on the stack portion 56.

[0024] After passing through the secondary transfer nip, the intermediate transfer belt 22 has its surface cleaned by the belt cleaning device 71. A cleaning backup roller 72 backs up the belt cleaning device 71 from inside the loop.

[0025] A manual feed tray 93 is provided on the side cover of the casing so as to be openable and closable relative to the side cover. Recording paper inserted into the manual feed tray 93 is fed to the register roller pair 43 of the paper feed path by the rotational drive of the manual feed roller 94.

[0026] [Drive transmission device] In Figure 1, a drive transmission device 101 according to the present invention, which transmits driving force to the paper feed roller 42 and the like, is arranged further back in the figure than the paper feed cassette 41. This drive transmission device 101 transmits driving force not only to the paper feed roller 42, but also to the registration roller pair 43, the double-sided transport roller pair 92, and the manual feed roller 94, and is configured to be detachable from the housing.

[0027] Examples of a drive transmission device 101 to which the present invention is applied are shown in Figures 3, 4, and 7. Figure 3 is a perspective view showing an example of a drive transmission device. Figure 4 is a perspective view showing the drive transmission device with various clutch gears, various intermediate gears, and the paper feed drive motor removed. Figure 8 is a schematic side view showing the drive transmission device.

[0028] The drive transmission device 101 of this embodiment is a drive transmission device that is detachably attached to a main unit (for example, an image forming apparatus) on which a driven object to which driving force is to be transmitted is mounted, and comprises a rotating shaft member 114 that rotates in response to driving force from a drive source, a bearing member 140 through which the rotating shaft member 114 is inserted, two holding members 102 and 103 that are spaced apart and facing each other and have through holes formed therein, and an electromagnetic clutch member 108 disposed between the two holding members 102 and 103, wherein one end of the rotating shaft member 114 is inserted through the through hole of one holding member 103 via the bearing member 140, and the other end is inserted through the through hole of the other holding member 102, and the rotating shaft member 114 and the bearing member 140 have an engagement structure in which they engage with each other along the circumferential direction of the rotating shaft.

[0029] The two retaining members 102 and 103 are one made of a resin material and the other made of a metal material. In this embodiment, the components are a metal bracket 102 and a resin cover 103. The metal bracket 102 and the resin cover 103 are connected by three studs 121, which are fixed shaft members that are sandwiched between them in a non-contact manner. One end of each stud 121 is fixed to the metal bracket 102 by being inserted into a through hole provided in the metal bracket 102. The other end of each stud 121 is provided with an axially extending female thread. A bolt passed through a through hole provided in the resin cover 103 is fastened to the female thread on the other end of the stud 121. In this way, the other end of the stud 121 is fixed to the resin cover 103.

[0030] In this way, by connecting the metal bracket 102 and the resin cover 103 with a stud 121 that does not have a toe, the drive transmission device 101 can be made smaller compared to when it is connected by a leg with a toe.

[0031] Furthermore, the metal bracket 102 and the resin cover 103 are positioned opposite each other with a gap between them due to the interposition of the stud 121, creating a gap. Within this gap are rotatable electromagnetic clutch members: a resist clutch gear 108, a paper feed clutch gear 105, a manual feed clutch gear 106, and a double-sided clutch gear 107. In addition, rotatable first relay gear 130, second relay gear 131, third relay gear 132, and fourth relay gear 133 are also provided.

[0032] The metal bracket 102 and the resin cover 103 rotatably hold the resist shaft gear. The resist shaft gear comprises a rotating shaft member 114 and a resist gear 110 as a drive component fixed to one end thereof, and both, made of resin material, rotate integrally.

[0033] Similarly, the metal bracket 102 and the resin cover 103 rotatably hold the paper feed shaft coupling, the double-sided shaft gear, and the manual feed shaft gear. The paper feed shaft coupling comprises a rotating shaft member 113 and a paper feed coupling 109 fixed to one end thereof, and both, made of resin material, rotate integrally. The double-sided shaft gear comprises a rotating shaft member 115 and a double-sided gear 111 fixed to one end thereof, and both, made of resin material, rotate integrally. The manual feed shaft gear comprises a rotating shaft member 116 and a manual feed gear 112 fixed to one end thereof, and both, made of resin material, rotate integrally.

[0034] As shown in Figure 4, each rotating shaft member passes through both the metal bracket 102 and the resin cover 103, and is rotatably supported by both. In addition, the drive component provided at one end in the axial direction is positioned on the outside of the resin cover 103. For example, a drive component 110 provided at one axial end of the rotating shaft member 114 is positioned outside the resin cover 103, and the rotating shaft member 114 is rotatably supported by a bearing member (sliding bearing) 140.

[0035] Figure 5 is a perspective view showing the electromagnetic clutch member 108. The electromagnetic clutch member 108 comprises a gear portion 108a provided on its outer periphery, an electromagnetic clutch portion 108b provided inside it, and a through hole 108c extending through it at its rotation center position. The gear shape of the gear portion 108a is a helical gear. In the drive transmission device 101, various clutch gears and various intermediate gears are all helical gears. The electromagnetic clutch section 108b rotates together with the gear section 108a when energized. On the other hand, when the power is cut off, even though it rotates on its own, it does not transmit its rotational force to the gear section 108a, and instead spins freely inside the gear section 108a. The cross-sectional shape of the through hole 106c is not a perfect circle, but rather resembles the letter "D".

[0036] Figure 6 is a perspective view showing the rotating shaft member 114, bearing member 140, and electromagnetic clutch member 108 that constitute the resist shaft gear. The cross-sectional shape of the rotating shaft member 114 is not a perfect circle, but rather resembles the letter "D". The electromagnetic clutch member 108 engages with the rotating shaft member 114 by passing it through the resist clutch through hole 108c. When the resist shaft gear rotates, the electromagnetic clutch part 108b that is engaged with it rotates together with it. At this time, if the electromagnetic clutch part 108b is energized, the gear part 108a also rotates together with it. In contrast, if the electromagnetic clutch part 108b is not energized, the gear part 108a does not rotate, and the electromagnetic clutch part 108b spins freely inside the gear part 108a. Also, even if the gear part 108a rotates due to an external rotational force, the electromagnetic clutch part 108b does not rotate, and the gear part 108a spins freely on the electromagnetic clutch part 106b.

[0037] When the drive transmission device 101 is set in the main body of the image forming apparatus, the drive member (resist gear) 110 of the resist shaft gear meshes with a gear fixed to the shaft of one of the resist rollers in the resist roller pair. As a result, the rotational force of the resist gear 110 is transmitted to the resist roller.

[0038] In the drive transmission device 101, as shown in Figure 7, one end of the rotatable rotating shaft member 114 in the axial direction is passed through one of the opposing members, the resin cover 103, and is held in a rotatable position. In addition to rotating the rotating shaft member 114 inside the resin cover 103 (the side facing the metal bracket 102), it is also possible to rotate it outside the resin cover 103. A gear or coupling, which serves as the drive transmission unit, is provided at the part of the rotating shaft member 114 that rotates outside the resin cover 103.

[0039] The drive from the drive gear 130 is transmitted to the drive member (resist roller) 110 via the electromagnetic clutch member 108, causing the driven gear 150 and the roller 151 on its axis to rotate. In the example of the resist shaft gear, roller 151 is a resist roller. The paper feed clutch gear 105, manual feed clutch gear 106, and double-sided clutch gear 107 in the figure are the corresponding transport rollers, etc.

[0040] In this embodiment, a bearing member 140 is provided between the rotating shaft member 114, which is integrated with the drive component 110, and the resin cover 103. A lubricant such as grease is applied between the rotating shaft member 114 and the bearing member 140 (the part indicated by the reference numeral L in Figure 7) to prevent wear and noise.

[0041] However, as shown in Figure 9(B), the applied lubricant 160 may leak out along the rotating shaft member 114 over time. The leaked lubricant 160 may reach the electromagnetic clutch member 108 located at the end of the direction of the arrow and penetrate into its interior. The oil content in lubricants can negatively affect the operation of electromagnetic clutches. For example, it can cause malfunctions such as the clutch not engaging or disengaging properly.

[0042] In contrast, the drive transmission device according to the present invention, as shown in Figures 8 and 9(A), has an engagement structure (114a, 140a) in which the rotating shaft member 114 and the bearing member 140 engage with each other along the circumferential direction of the rotating shaft, and the coil bearing member 140 forms a circumferential wall shape that covers the rotating shaft member 114, thereby preventing lubricant from adhering to or entering the electromagnetic clutch member 108.

[0043] Figure 10 is a perspective view showing an example of a rotating shaft member 114 integrated with a drive component 110. Figure 10(A) shows the rotating shaft member 114 of the device according to this embodiment having an engagement structure 114a, while Figure 10(B) shows a conventional example without an engagement structure. Figure 11 is a perspective view showing an example of a bearing member 140. Figure 11(A) shows a bearing member 140 included in the device according to this embodiment, which has an engagement structure 140a, while Figure 11(B) shows a conventional example without an engagement structure. The engagement structure 140a is formed on the end side of the bearing member 140 that faces the electromagnetic clutch member 108.

[0044] The protrusions formed on the bearing member 140 of the engagement structure are, for example, rib structures provided along the circumferential direction of the rotating shaft. The rib structure exists around the entire circumference of the rotating shaft. Here, "one full rotation" essentially means a 360-degree rotation, including sections with small angle breaks and sections divided into multiple protrusions. In any embodiment, the lubricant 160 can be designed and manufactured into any desired shape as long as it prevents leakage toward the electromagnetic clutch member 180.

[0045] On the other hand, the recess formed in the rotating shaft member 114 is a groove-like structure provided along the circumferential direction of the rotating shaft. This structure creates steps and peripheral walls on the surface where the lubricant 160 is applied, which was previously flat, thus preventing the lubricant 160 from leaking out.

[0046] During assembly of the device, the rotating shaft member 114 and the bearing member 140 are press-fitted together until they engage with each other, preventing them from falling out. Furthermore, during maintenance such as replacing the electromagnetic clutch member 108, the applied lubricant remains in the recess of the rotating shaft member 114, improving maintainability.

[0047] According to the drive transmission device of this embodiment, it is possible to prevent lubricant from adhering to or entering the electromagnetic clutch member 108. Without providing any new parts, operational malfunctions such as electromagnetic clutch disconnection can be prevented, resulting in a highly reliable drive transmission device. [Explanation of Symbols]

[0048] 102 Retaining member (metal bracket) 103 Retaining member (resin cover) 108 Electromagnetic clutch component 108a Gear section 108b Electromagnetic clutch section 108c through hole 110 Drive components 114 Rotating shaft member 114a Engagement structure (protrusion) 130 relay gear 140 Bearing member 140a Engagement structure (recess) 150 Driven component (gear) 151 Laura 160 Lubricant [Prior art documents] [Patent Documents]

[0049] [Patent Document 1] Japanese Patent Publication No. 2017-167201

Claims

1. A drive transmission device that is detachably attached to a main unit that is equipped with a driven object to which driving force is to be transmitted, A rotating shaft member that rotates by receiving driving force from a drive source, The bearing member through which the aforementioned rotating shaft member is inserted, Two holding members, each having a through hole, are positioned opposite each other with a gap between them, The system comprises an electromagnetic clutch member disposed between the two holding members, The rotating shaft member has one end in the axial direction inserted through the through hole of one of the holding members via the bearing member, and the other end inserted through the through hole of the other holding member. A drive transmission device characterized in that the rotating shaft member and the bearing member have an engagement structure in which they engage with each other along the circumferential direction of the rotating shaft.

2. The drive transmission device according to claim 1, characterized in that the engagement structure is a protrusion formed on the bearing member and a recess formed on the rotating shaft member.

3. The drive transmission device according to claim 2, characterized in that the protrusion formed on the bearing member of the engagement structure is a rib structure provided over the circumference of the rotating shaft.

4. The drive transmission device according to any one of claims 1 to 3, characterized in that the engagement structure is formed on the end side of the bearing member facing the electromagnetic clutch member.

5. The drive transmission device according to any one of claims 1 to 4, characterized in that the rotating shaft member is made of a resin material.

6. The drive transmission device according to any one of claims 1 to 5, characterized in that one of the two holding members is made of a resin material and the other is made of a metal material.

7. In an image forming apparatus equipped with a drive transmission means for driving a driven object, An image forming apparatus characterized in that the drive transmission means comprises a drive transmission device according to any one of claims 1 to 6.

Images