Image forming apparatus

Abstract

This invention provides an image forming apparatus that, compared to a case where a first adjusting member for adjusting load and an adjusting member for adjusting parallelism are provided on the side of a first rotating member, performs parallelism adjustment and load adjustment with good accuracy. The image forming apparatus includes: a first unit having an annular strip member and a first rotating member supporting and rotating the strip member; a second unit having a second rotating member disposed opposite to the first rotating member across the strip member and capable of rotation; a first adjusting member disposed in one of the first and second units, adjusting the load between the first and second rotating members; and a second adjusting member disposed in the other of the first and second units, adjusting the parallelism between the first and second rotating members.

Description

Technical Field

[0001] This invention relates to an image forming apparatus. Background Technology

[0002] In image forming apparatuses such as copiers, printers, and fax machines, the technology described in Patent Document 1 is known to be capable of moving to adjust the position between an annular member such as an intermediate transfer belt and a member facing the annular member.

[0003] Japanese Patent Application Publication No. 2017-68186, which is patent document 1, describes a structure in which a moving mechanism 100 is provided on the side of the support roller 165 to adjust the position of the support roller 165 supporting the intermediate transfer belt 151 and the secondary transfer roller 154 supporting the secondary transfer belt 153. The moving mechanism 100 of Patent Document 1 has the function of adjusting the horizontal position of the support roller 165.

[0004] [Existing technical documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-68186 (“0040”-“0059”) Figure 3 -Figure 6) Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] The technical challenge of this invention is to perform parallelism adjustment and load adjustment with good accuracy compared to the case where a first adjusting member for adjusting load and an adjusting member for adjusting parallelism are provided on the side of the first rotating member. The load is the load between the first rotating member supporting the annular strip member and the second rotating member facing the first rotating member, and the parallelism is the parallelism between the first rotating member and the second rotating member.

[0009] [Technical means to solve the problem]

[0010] To solve the aforementioned technical problem, the image forming apparatus of the embodiment described in technical solution 1 includes:

[0011] The first unit has a first ring-shaped strip component and a first rotating component, wherein the first rotating component supports the first strip component and rotates.

[0012] The second unit has a second rotating component, which is arranged facing the first rotating component across the first strip component and is capable of rotation;

[0013] A first adjusting component, disposed in one of the first unit and the second unit, adjusts the load between the first rotating component and the second rotating component; and

[0014] A second adjustment component is disposed in the other of the first unit and the second unit to adjust the parallelism between the first rotating component and the second rotating component.

[0015] The embodiment described in technical solution 2, based on the image forming apparatus described in technical solution 1, includes:

[0016] The second unit has a ring-shaped second strip member, which is supported by the second rotating member and rotates.

[0017] The embodiment described in technical solution 3, based on the image forming apparatus described in technical solution 2, includes:

[0018] The second unit has a suppressing component that suppresses the offset of the second strip-shaped component in the width direction.

[0019] The embodiment described in technical solution 4, based on the image forming apparatus described in technical solution 2 or 3, includes:

[0020] The first strip-shaped component retains the image on the surface; and

[0021] The second strip component transports the image from the surface of the first strip component to the medium.

[0022] The embodiment described in technical solution 5, according to any one of technical solutions 1 to 4, includes an image forming apparatus comprising:

[0023] The first adjusting component adjusts the position of both ends of the rotation axis of one of the first and second rotating components relative to the first rotating component and the second rotating component, thereby adjusting the load.

[0024] The embodiment described in technical solution 6, based on the image forming apparatus described in technical solution 5, includes:

[0025] The first adjusting component includes a first eccentric component supported at both ends of the rotating shaft of one of the rotating components, and adjusts the distance between the first eccentric component and the second unit as the first eccentric component rotates, thereby adjusting the position of the two ends of the rotating shaft.

[0026] The embodiment described in technical solution 7, according to any one of technical solutions 1 to 6, includes an image forming apparatus comprising:

[0027] The second adjusting component adjusts the position of one end of the rotation axis of the other rotating component relative to the first rotating component and the other rotating component of the second rotating component, thereby adjusting the parallelism.

[0028] The embodiment described in technical solution 8, based on the image forming apparatus described in technical solution 7, includes:

[0029] The second adjusting component includes a second eccentric component supported on the rotation axis of the other rotating component, and adjusts the spacing of one end of the rotation axis of the other rotating component relative to the first unit as the second eccentric component rotates, thereby adjusting the position of the one end.

[0030] The embodiment described in technical solution 9, according to any one of technical solutions 1 to 8, includes an image forming apparatus comprising:

[0031] The first adjustment component is disposed in the first unit; and

[0032] The second adjustment component is disposed in the second unit.

[0033] The embodiment described in technical solution 10, based on the image forming apparatus described in technical solution 9, includes:

[0034] The first adjusting component adjusts the load by adjusting the interval relative to the second unit; and

[0035] The second adjustment component adjusts the parallelism by adjusting the interval relative to the first unit, and the adjustment amount of the interval of the second adjustment component is smaller than that of the first adjustment component.

[0036] The embodiment described in technical solution 11, based on the image forming apparatus described in technical solution 10, includes:

[0037] The second unit is disposed below the first unit in the direction of gravity and is detachably mounted relative to the main body of the image forming apparatus.

[0038] The embodiment described in technical solution 12, based on the image forming apparatus described in technical solution 10 or 11, includes:

[0039] The second unit has a second strip member, which is an annular second strip member supported and rotated by the second rotating member, and has lower rigidity than the first strip member of the first unit.

[0040] [The effects of the invention]

[0041] According to the embodiment described in technical solution 1, compared with the case where a first adjusting member for adjusting the load and an adjusting member for adjusting the parallelism are provided on the side of the first rotating member, the parallelism adjustment and load adjustment are performed with good accuracy. The load is the load between the first rotating member supporting the annular strip member and the second rotating member facing the first rotating member, and the parallelism is the parallelism between the first rotating member and the second rotating member.

[0042] According to the embodiment described in technical solution 2, even in a structure where two strip-shaped components face each other, the load and parallelism can be adjusted with good precision.

[0043] According to the embodiment described in technical solution 3, compared with the case of using the second adjustment unit to adjust parallelism and suppress offset, parallelism adjustment and offset suppression can be performed stably.

[0044] According to the embodiment described in technical solution 4, compared with the case where there is no second strip member in the transfer area, the posture of the medium can be stabilized and poor transfer can be suppressed.

[0045] According to the embodiment described in technical solution 5, the position of both ends of the rotating shaft can be adjusted to change the biting amount of one rotating component relative to another rotating component, and the load can be adjusted.

[0046] According to the implementation method described in technical solution 6, manufacturing costs are easier to suppress compared to the case where eccentric components are not used.

[0047] According to the embodiment described in technical solution 7, the position of one of the rotating shafts can be adjusted so that the rotating shaft of the other rotating component is relatively tilted relative to one of the rotating components, thereby adjusting the parallelism.

[0048] According to the implementation method described in technical solution 8, manufacturing costs are easier to suppress compared to the case where eccentric components are not used.

[0049] According to the embodiment described in technical solution 9, the load can be adjusted on the first unit side having the strip member, and the parallelism can be adjusted on the second unit side.

[0050] According to the embodiment described in technical solution 10, the interval can be finely adjusted using the second adjustment unit on the second unit side.

[0051] According to the embodiment described in technical solution 11, the lower second unit can be detached from the image forming apparatus, and the user can make fine adjustments using the second adjustment component while checking from above.

[0052] According to the embodiment described in technical solution 12, the second adjustment component can be used to make fine adjustments to the second strip component, which has lower rigidity and is easier to adjust compared to the strip component of the first unit. Attached Figure Description

[0053] Figure 1 This is an overall explanatory diagram of the image forming apparatus of Embodiment 1.

[0054] Figure 2 This is an enlarged illustration of the visible image forming apparatus of Embodiment 1.

[0055] Figure 3 This is an explanatory diagram of the adjustment mechanism in Example 1.

[0056] Figure 4 This is an explanatory diagram of the support roller unit.

[0057] Figure 5 This is an explanatory diagram of the secondary transfer unit in Example 1.

[0058] [Explanation of Symbols]

[0059] 7: First eccentric component

[0060] 7~11: First Adjustment Component

[0061] 42: Second eccentric component

[0062] 42-46: Second Adjustment Components

[0063] 51: Suppression component

[0064] B: Strip-shaped component

[0065] BM: Unit 1

[0066] BTB: Second Strip Component

[0067] S: Medium

[0068] T2a: First rotating component

[0069] T2b: Second rotating component

[0070] U: Image forming apparatus

[0071] Ut: Unit 2 Detailed Implementation

[0072] Next, specific examples of embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

[0073] Furthermore, to facilitate understanding of the following explanations, in the accompanying drawings, the front-back direction is set as the X-axis direction, the left-right direction as the Y-axis direction, and the up-down direction as the Z-axis direction. The directions or sides represented by the arrows X, -X, Y, -Y, Z, and -Z are respectively set as front, back, right, left, top, bottom, or front side, back side, right side, left side, top side, and bottom side.

[0074] Additionally, in the diagram, the "·" inside the "○" indicates an arrow pointing from the back of the paper towards the front, and the "×" inside the "○" indicates an arrow pointing from the front of the paper towards the back.

[0075] Furthermore, in the following description using the accompanying drawings, illustrations other than those required for the description may be omitted for ease of understanding.

[0076] [Example 1]

[0077] Figure 1 This is an overall explanatory diagram of the image forming apparatus of Embodiment 1.

[0078] Figure 2 This is an enlarged illustration of the visible image forming apparatus of Embodiment 1.

[0079] exist Figure 1 In this example, a copier U, which is an image forming apparatus, includes: a user interface UI, which is an operation unit, a scanner unit U1, which is an image reading device, a feeder unit U2, which is a media supply unit, an imaging unit U3, which is an image recording device, and a media processing unit U4.

[0080] (User Interface) Description

[0081] The user interface (UI) has an input button UIa for setting the start of copying or the number of copies, etc. Additionally, the user interface (UI) has a display section UIb that displays the content entered via the input button UIa or the status of the copier U.

[0082] (Explanation of feeder section U2)

[0083] exist Figure 1 In this unit, the feeder section U2 has multiple paper trays TR1, TR2, TR3, and TR4, which serve as media receiving components. Additionally, the feeder section U2 has a media supply path SH1, which takes out a recording sheet S, an example of an image recording medium, that has been received in each of the paper trays TR1 to TR4 and transports it toward the imaging section U3.

[0084] (Description of Imaging Unit U3 and Media Processing Device U4)

[0085] exist Figure 1 In the imaging unit U3, there is an image recording unit U3a, which records an image on a recording paper S conveyed from the feeder unit U2 based on the original image read by the scanner unit U1.

[0086] exist Figure 1 , Figure 2 In the imaging unit U3, the drive circuit D of the latent image forming apparatus outputs drive signals corresponding to the image information input from the scanner unit U1 at a predetermined time to the latent image forming apparatuses ROSy, ROSm, ROSc, and ROSk of each color (Y to K), which are examples of latent image forming components. Below each latent image forming apparatus ROSy to ROSk, photosensitive drums Py, Pm, Pc, and Pk, which are examples of image holding components, are arranged.

[0087] The surfaces of the rotating photoreceptor drums Py, Pm, Pc, and Pk are also charged by charged rollers CRy, CRm, CRc, and CRk, which are examples of charged components. An electrostatic latent image is formed on the surfaces of the already charged photoreceptor drums Py to Pk by laser beams Ly, Lm, Lc, and Lk, which are examples of latent image writing light, output from latent image forming apparatuses ROSy, ROSm, ROSc, and ROSk. Using developing apparatuses Gy, Gm, Gc, and Gk, which are examples of developing components, the electrostatic latent images on the surfaces of photoreceptor drums Py, Pm, Pc, and Pk are developed into toner images, which are examples of visible images, in yellow (Y), magenta (M), cyan (C), and black (K).

[0088] Furthermore, in the developing apparatuses Gy to Gk, the developer consumed during development is replenished from toner cartridges Ky, Km, Kc, and Kk, which serve as containers for the developer. Toner cartridges Ky, Km, Kc, and Kk are detachably mounted on the developer replenishment device U3b.

[0089] Using primary transfer rollers T1y, T1m, T1c, and T1k, which are examples of primary transfer components, toner images from the surfaces of photoreceptor drums Py, Pm, Pc, and Pk are sequentially transferred onto primary transfer areas Q3y, Q3m, Q3c, and Q3k on intermediate transfer belt B, which is an example of intermediate transfer components. A color toner image, an example of a multicolor visible image, is thus formed on intermediate transfer belt B. The color toner image formed on intermediate transfer belt B is then conveyed to secondary transfer area Q4.

[0090] Furthermore, when only K-color image information is available, only the K-color photosensitive drum Pk and the developing device Gk are used to form a K-color toner image.

[0091] After one transfer, the photoconductor drums Py, Pm, Pc, and Pk are cleaned by drum cleaners CLy, CLm, CLc, and CLk, which are examples of cleaning components used as image holding components, to remove residual developer or paper dust and other residues that have adhered to the surface.

[0092] In Example 1, the photoreceptor drum Pk, the charged roller CRk, and the drum cleaner CLk are integrated as a K-color photoreceptor unit UK, which is an example of an image holding unit. Furthermore, for other colors Y, M, and C, the photoreceptor units UY, UM, and UC are similarly constructed from photoreceptor drums Py, Pm, and Pc, charged rollers CRy, CRm, and CRc, and drum cleaners CLy, CLm, and CLc.

[0093] Furthermore, a visible image forming apparatus UK+Gk for K colors is constructed from a photoreceptor unit UK of K colors and a developing device Gk having a developing roller R0k as an example of a developing agent holding component. Similarly, visible image forming apparatuses UY+Gy, UM+Gm, and UC+Gc for Y, M, and C colors are constructed from photoreceptor units UY, UM, and UC of Y, M, and C colors, and developing devices Gy, Gm, and Gc having developing rollers R0y, R0m, and R0c, respectively.

[0094] Below the photosensitive drums Py to Pk, a belt assembly BM, exemplified as an intermediate transfer device, is disposed. The belt assembly BM includes: an intermediate transfer belt B, exemplified as an image holding member; a drive roller Rd, exemplified as a drive member for the intermediate transfer body; a tension roller Rt, exemplified as a tension imparting member; a travel roller Rw, exemplified as a serpentine prevention member; multiple idle rollers Rf, exemplified as driven members; a support roller T2a, exemplified as an opposing member; and the primary transfer rollers T1y, T1m, T1c, and T1k. The intermediate transfer belt B is supported in a manner capable of rotating and moving in the direction of arrow Ya.

[0095] A secondary transfer unit Ut is disposed below the support roller T2a. The secondary transfer unit Ut has a secondary transfer belt BTB, which is an example of a ring-shaped member, and a secondary transfer roller T2b, which is an example of a secondary transfer member. The secondary transfer area Q4 is formed by the secondary transfer roller T2b in contact with the intermediate transfer belt B, separated by the secondary transfer belt BTB. The support roller T2a, as an example of an opposing member, faces the secondary transfer roller T2b, separated by the secondary transfer belt BTB and the intermediate transfer belt B. A contact roller T2c, as an example of a power supply member, contacts the support roller T2a. A secondary transfer voltage of the same polarity as the charged polarity of the toner is applied to the contact roller T2c.

[0096] The secondary transfer unit T2 is composed of the support roller T2a, the secondary transfer roller T2b, and the contact roller T2c, which is an example of a secondary transfer component.

[0097] A media transport path SH2 is arranged below the belt assembly BM. Recording paper S supplied from the media supply path SH1 of the feeder unit U2 is transported by a transport roller Ra, an example of a media transport member, towards a registration roller Rr, an example of a transport timing adjustment member. During the period when the toner image formed on the intermediate transfer belt B is transported to the secondary transfer area Q4, the registration roller Rr transports the recording paper S downstream. The recording paper S delivered by the registration roller Rr is guided by the registration-side paper guide SGr and the pre-transfer paper guide SG1, and is transported to the secondary transfer area Q4.

[0098] The toner image on the intermediate transfer belt B is transferred to the recording paper S by the secondary transfer unit T2 when it passes through the secondary transfer area Q4. In addition, in the case of color toner images, the toner image that has been transferred once on the surface of the intermediate transfer belt B is also transferred to the recording paper S a second time.

[0099] The transfer device T1y~T1k+T2+B, which is an example of a transfer component, consists of the primary transfer rollers T1y~T1k, the secondary transfer device T2, and the intermediate transfer belt B.

[0100] After the secondary transfer, the intermediate transfer belt B is cleaned by a belt cleaner CLB, which is located downstream of the secondary transfer area Q4 and serves as an example of an intermediate transfer cleaning component. As an example of a removal component, the belt cleaner CLB removes residual developer or paper dust that was not transferred in the secondary transfer area Q4 from the intermediate transfer belt B.

[0101] Recording paper S, on which the toner image has been transferred, is fed to a media conveyor belt BH, which is one example of a conveying component. The media conveyor belt BH transports the recording paper S to the fixing unit F.

[0102] A fixing device F, as an example of a fixing component, includes a heating roller Fh, as an example of a heating component, and a pressure roller Fp, as an example of a pressure component. Recording paper S is conveyed to a fixing region Q5, which is the area where the heating roller Fh and the pressure roller Fp come into contact. As the toner image of the recording paper S passes through the fixing region Q5, it is fixed by heating and pressure from the fixing device F.

[0103] The image recording unit U3a of Embodiment 1 is composed of the visible image forming apparatus UY+Gy to visible image forming apparatus UK+Gk, the transfer apparatus T1y to T1k+T2+B, and the fixing apparatus F, which is an example of an image forming component.

[0104] Downstream of the fixing unit F, a switching gate GT1 is provided as an example of a switching member. The switching gate GT1 selectively switches the recording paper S that has passed through the fixing area Q5 to either the discharge path SH3 or the reversing path SH4 on the media processing unit U4 side. The recording paper S, which has been conveyed to the discharge path SH3, is conveyed towards the paper conveying path SH5 of the media processing unit U4. In the paper conveying path SH5, a curl correction member U4a is provided as an example of a warp correction member. The curl correction member U4a corrects the warp, or so-called curl, of the received recording paper S. The corrected recording paper S, with its image fixing surface facing upwards, is discharged by the discharge roller Rh, an example of a media discharge member, towards the discharge tray TH1, an example of a media discharge section.

[0105] The recording paper S, which is conveyed by the switching gate GT1 toward the reverse path SH4 of the imaging unit U3, is conveyed to the reverse path SH4 of the imaging unit U3 through the second gate GT2, which is an example of a switching component.

[0106] At this time, with the image fixing surface of the recording paper S being discharged downwards, after the recording paper S passes through the second gate GT2 at its rear end in the transport direction, the transport direction of the recording paper S is reversed. Here, the second gate GT2 in Embodiment 1 includes a thin-film elastic member. Therefore, the second gate GT2 allows the recording paper S, which has been transported to the reversing path SH4, to pass directly and temporarily. If the recorded paper S that has passed through is reversed, i.e., switched back, it is guided towards the transport paths SH3 and SH5. Moreover, the switched-back recording paper S is discharged towards the discharge tray TH1 with the image fixing surface facing downwards via the curl correction member U4a.

[0107] The imaging unit U3 has a reversal path SH4 connected to a circulation path SH6, and a third gate GT3, serving as a switching component, is disposed at their connection point. Furthermore, the downstream end of the reversal path SH4 is connected to the reversal path SH7 of the media processing device U4.

[0108] Recording paper S, conveyed to the reversing path SH4 via the switching gate GT1, is then conveyed by the third gate GT3 towards the reversing path SH7 side of the media processing device U4. The third gate GT3 of Embodiment 1, like the second gate GT2, includes a thin-film elastic member. Therefore, the third gate GT3 allows the recording paper S conveyed on the reversing path SH4 to pass temporarily, and if the already passed recording paper S is turned back, it is guided towards the circulation path SH6 side.

[0109] The recording paper S, which has been transported to the circulation path SH6, is transported again to the secondary transfer area Q4 after passing through the medium transport path SH2 for printing on the second side.

[0110] The paper transport path SH is constituted by the elements represented by symbols SH1 to SH7. In addition, the paper transport device SU of Embodiment 1 is constituted by the elements represented by symbols SH, Ra, Rr, Rh, SGr, SG1, BTB, BH, and GT1 to GT3.

[0111] (Explanation of the adjustment mechanism)

[0112] Figure 3 This is an explanatory diagram of the adjustment mechanism in Example 1.

[0113] Figure 4 This is an explanatory diagram of the support roller unit.

[0114] exist Figure 3In the first unit, a support roller unit 1, serving as a first adjustment unit, is supported at the lower part of the belt assembly BM. The support roller unit 1 includes a support roller T2a, serving as a first rotating component, and a housing 2 covering both ends and the top of the support roller T2a along its axial direction. Bearing members 4, supporting the rotation axis 3 of the support roller T2a, are supported at both ends of the housing 2 in a manner that allows them to approach or separate from the secondary transfer roller T2b. A helical spring 6, serving as a force-applying component, is installed between the bearing member 4 and the housing 2. The helical spring 6 applies a force that presses the support roller T2a towards the secondary transfer roller T2b side.

[0115] At the front and rear end faces of the housing 2, a switching cam 7, as an example of a first eccentric component, is supported at a position coaxial with the rotation axis 3 of the support roller T2a. Furthermore, Figure 3 , Figure 4 Only the front switching cam 7 is shown in the figure, but the same structure is also configured on the rear side. The switching cam 7 has an outer surface 7a whose outer diameter changes as it travels in the circumferential direction, i.e., it contains a so-called eccentric cam.

[0116] The switching cam 7 has a gear section 7b, which is an example of a gear. A first intermediate gear 8, which is also an example of a gear, meshes with the gear section 7b. The first intermediate gear 8 is supported on the outer surface of the housing 2 in a rotatable manner.

[0117] A first intermediate gear 8 meshes with a first transmission gear 9, which is an example of a gear. The first intermediate gear 8 supports a transmission shaft 10, which is an example of a transmission component. The transmission shaft 10 extends in the front-rear direction and is rotatably supported at the front and rear ends of the housing 2.

[0118] A driven gear 11, which is an example of a gear, is supported at the rear end of the transmission shaft 10. The driven gear 11 meshes with a rear intermediate gear (not shown), and the rear intermediate gear meshes with a gear portion of a switching cam (not shown).

[0119] The driven gear 11 is driven by a drive gear (not shown) provided in the main body of the copier U. Therefore, when the drive is transmitted to the driven gear 11, the front switching cam 7 rotates via the transmission shaft 10, the first transmission gear 9, and the first intermediate gear 8, while the rear intermediate gear (not shown) and the switching cam also rotate.

[0120] The load adjustment mechanism 7 to load adjustment mechanism 11, which are examples of first adjustment components, are composed of the switching cam 7, the first intermediate gear 8, the first transmission gear 9, the transmission shaft 10, and the driven gear 11.

[0121] Figure 5 This is an explanatory diagram of the secondary transfer unit in Example 1.

[0122] exist Figure 2 , Figure 3 In the middle, a secondary transfer unit Ut is arranged below the component BM as an example of the second unit.

[0123] exist Figure 3 , Figure 5 In this embodiment, the secondary transfer unit Ut has a secondary transfer belt BTB, which serves as an example of a second strip component. The secondary transfer belt BTB of Embodiment 1 comprises an elastic rubber strip, and compared to the intermediate transfer belt B, which comprises polyimide or polyamide-imide, it comprises a material with low rigidity and low hardness. The secondary transfer belt BTB is supported by a secondary transfer roller T2b, which serves as an example of a second rotating component, and a driven roller 31. The secondary transfer unit Ut has a pair of front and rear frames 32 and 33, which serve as an example of a frame.

[0124] A support plate 34, serving as an example of a movable support member, is supported on the front surface of the front frame 32. The support plate 34 is rotatably supported on the front frame 32 with a movable shaft 34a as its center. The secondary transfer roller T2b is supported on the support plate 34 to the right of the movable shaft 34a. A cam follower 36, serving as an example of a passive working member, is supported on the support plate 34 to the left of the movable shaft 34a. Additionally, one end of a coil spring 37, serving as an example of a force-applying member, is connected to the support plate 34 below the movable shaft 34a. The other end of the coil spring 37 is supported on the front frame 32. In Embodiment 1, the coil spring 37 stretches the lower end of the support plate 34 to the right and applies a force in the direction of applying force to the secondary transfer roller T2b towards the support roller T2a.

[0125] Below the cam follower 36, a retract cam 38, serving as an example of a separation component, is supported on the front frame 32 in a manner rotatable about a camshaft 38a. The retract cam 38 has a contact portion 38b that is eccentric relative to the camshaft 38a and contacts the cam follower 36. Furthermore, the camshaft 38a of the retract cam 38 extends to the rear end of the secondary transfer unit Ut, and at the rear end of the camshaft 38a, a retract gear 39, serving as an example of a drive transmission component, is supported. The drive is configured to transmit power from a drive source (not shown) provided in the copier U to the retract gear 39.

[0126] The support plate 34, cam follower 36, coil spring 37, and retractable cam 38 are supported not only in the front frame 32 but also in the rear frame 33. Furthermore, they are configured such that the front and rear retractable cams 38 rotate in tandem via the camshaft 38a.

[0127] The retraction mechanism 34 to retraction mechanism 39 of Embodiment 1 are constituted by the parts marked with the symbols 34 to 39, as an example of a separation contact component.

[0128] At the front end of the shaft 41 of the secondary transfer roller T2b, a fine-tuning cam 42, serving as an example of a second eccentric component, is supported. The outer surface 42a of the fine-tuning cam 42 is configured to contact the outer surface 7a of the switching cam 7. The shape of the outer surface 42a of the fine-tuning cam 42 is such that its outer diameter gradually increases from the smallest portion 42b to the largest portion 42c. Furthermore, a concave-convex ring 43 is formed on the front side of the fine-tuning cam 42, serving as an example of a stopped component. A plurality of recesses 43a are formed at intervals along the circumferential direction on the concave-convex ring 43. In Embodiment 1, as an example, 12 recesses 43a are formed at 30° intervals. In Embodiment 1, as an example, the outer diameter of the outer surface 42a is formed such that the outer diameter changes by 75 μm each time the recesses 43a advance by an amount of 30° along the circumferential direction.

[0129] A stop lever 44, serving as a stop component, is disposed to the lower left of the shaft 41 of the secondary transfer roller T2b. The stop lever 44 is movably supported on the front frame 32. In Embodiment 1, the stop lever 44 is configured to move along the line connecting the rotation axis 3 of the support roller T2a and the shaft 41 of the secondary transfer roller T2b. The top end 44a of the stop lever 44 is hemispherical, and receives a force toward the concave-convex ring 43 from a spring 46, which serves as a force-applying component.

[0130] The parts marked with the symbols 42 to 46 constitute a fine-tuning mechanism 42 to fine-tuning mechanism 46 as an example of a second adjustment component.

[0131] Furthermore, in Embodiment 1, the fine-tuning mechanisms 42 to 46 are disposed not only on the front side of the secondary transfer unit Ut, but also on the rear side. Moreover, unlike the retraction mechanisms 34 to 39, the front and rear fine-tuning mechanisms 42 to 46 are configured not to be linked, but rather to operate independently on the front and rear sides.

[0132] In the secondary transfer unit Ut, a travel adjustment mechanism 51, serving as a suppression member, is arranged at both ends of the driven shaft 31a of the driven roller 31 of the secondary transfer belt BTB. The travel adjustment mechanism 51 has an adjustment plate 52, serving as the main body of the suppression member. The adjustment plate 52 is respectively arranged on the outer surface of the front and rear frames 32 and 33. In Embodiment 1, the adjustment plate 52 is formed as a plate extending in the vertical direction. The outer end of the driven shaft 31a is rotatably supported on the adjustment plate 52. Furthermore, the travel adjustment mechanism 51 is arranged on both the front and rear sides; however, the front side will be described in detail below, and since the rear side is the same, detailed description will be omitted.

[0133] Guide grooves 53, serving as examples of guided parts, are formed at both the upper and lower ends of the adjusting plate 52. Guide protrusions 54, serving as examples of guiding members, are embedded in the guide grooves 53. The guide protrusions 54 are formed to protrude outwards from the front and rear frames 32 and 33. Therefore, by utilizing the guide grooves 53 and the guide protrusions 54, the adjusting plate 52 is configured to be movable along the direction of the guide grooves 53.

[0134] On the upper and lower sides of the driven shaft 31a, there are fixing holes 56, which serve as examples of fastened components. The fixing holes 56 are elongated holes formed in the adjusting plate 52 along the moving direction. Screws 57, which serve as examples of fastening components, pass through the fixing holes 56 and are screwed into the front frame 32. Therefore, when the screws 57 are tightened, the screw heads contact the adjusting plate 52, and the adjusting plate 52 is fixed in a non-movable state. When the screws 57 are loosened, the adjusting plate 52 becomes movable along the guide groove 53.

[0135] Below the fixing hole 56 on the lower side, a cam follower hole 58 is formed as an example of a passive working member. The cam follower hole 58 is formed as an elongated hole extending in the direction of the short side of the adjustment plate 52. A travel adjustment cam 59, as an example of a working member and as an example of a third eccentric member, is housed in the cam follower hole 58. The rotation axis 59a of the travel adjustment cam 59 is rotatably supported on the front frame 32. The travel adjustment cam 59 includes a so-called eccentric cam with a generally elliptical outer diameter relative to the rotation axis 59a. The travel adjustment cam 59 is configured such that the user can rotate the rotation axis 59a using a finger or a tool.

[0136] The walking adjustment mechanism 51 of Embodiment 1 is composed of the parts marked with symbols 52 to 59.

[0137] (The function of Example 1)

[0138] In the copier U of Embodiment 1, which includes the aforementioned structure, when image formation is performed, the retraction mechanisms 34 to 39 bring the secondary transfer roller T2b close to the support roller T2a, thereby bringing the intermediate transfer belt B, which is an example of a strip-shaped component, into contact with the secondary transfer belt BTB, which is an example of a second strip-shaped component. In this state, the recording paper S passing through the secondary transfer area Q4 is transferred. In Embodiment 1, when the printing operation ends, the secondary transfer belt BTB separates from the intermediate transfer belt B. Specifically, the drive is transmitted to the retraction cam 38 via the retraction gear 39, the contact portion 38b rotates, the cam follower 36 is pushed upward, and the helical spring 37 extends, causing the secondary transfer roller T2b to move in the direction of separation from the support roller T2a. As a result, the secondary transfer belt BTB, supported by the secondary transfer roller T2b, also separates from the intermediate transfer belt B. Furthermore, in Embodiment 1, the front and rear support plates 34 move in conjunction with each other via the camshaft 38a, so that the front and rear ends of the shaft 41 of the secondary transfer roller T2b move simultaneously in the direction of contacting and separating from the support roller T2a.

[0139] When performing a printing operation, if the type of recording paper S used is thick paper, a medium thicker than ordinary paper will enter between the intermediate transfer belt B and the secondary transfer belt BTB, sometimes resulting in excessive contact pressure and load. Correspondingly, in Embodiment 1, in the case of thick paper, the load adjustment mechanisms 7 to 11 operate, moving the support roller T2a in a direction separating it from the secondary transfer roller T2b, thereby reducing the load. On the other hand, when the recording paper S used changes from thick paper to ordinary paper, the load adjustment mechanisms 7 to 11 operate, moving the support roller T2a closer to the secondary transfer roller T2b, thereby increasing the load. Specifically, in the load adjustment mechanisms 7 to 11 of Embodiment 1, when the drive is transmitted to the driven gear 11, the switching cam 7 rotates, and the position of the outer surface 7a of the switching cam 7 in contact with the outer surface 42a of the fine-tuning cam 42 changes. Therefore, the relative position of the support roller T2a, coaxial with the switching cam 7, relative to the secondary transfer roller T2b changes. As a result, the interval and positional relationship between the support roller T2a, which is one example of a rotating component, and the secondary transfer roller T2b, which is another example of a rotating component, change, and the so-called bite amount changes. As a result, the contact pressure and load in the secondary transfer zone Q4 change.

[0140] Furthermore, in the copier U of Embodiment 1, due to individual differences, manufacturing errors, assembly errors, and wear over time, the positional relationship between the support roller T2a and the secondary transfer roller T2b—specifically, the degree to which the axial direction of the rotation axis 3 of the support roller T2a deviates from the parallel state of the axial direction of the axis 41 of the secondary transfer roller T2b—differs microscopically from the designed ideal state. If the parallelism differs from the design, the pressure distribution in the width direction of the recording paper S in the secondary transfer area Q4 changes, leading to uneven transfer defects, tilting of the recording paper S relative to the transport direction during passage, paper wrinkling, or serpentine or offset of the intermediate transfer belt B or the secondary transfer belt BTB. Correspondingly, in Embodiment 1, fine-tuning mechanisms 42 to 46 are provided. In the fine-tuning mechanisms 42 to 46 of Embodiment 1, when the user rotates the fine-tuning cam 42 using their hand or a tool, the outer surface 42a of the fine-tuning cam 42 rotates, thereby changing the position of contact with the outer surface 7a of the switching cam 7. Therefore, the outer diameter of the fine-tuning cam 42 in contact with the switching cam 7 changes, altering the interval between the secondary transfer roller T2b, which is coaxial with the fine-tuning cam 42, and the support roller T2a, which is coaxial with the switching cam 7. In Embodiment 1, fine-tuning mechanisms 42 to 46 are provided at the front and rear, and can be operated individually. Therefore, for the front side (one example) and the rear side (another example), the interval between the secondary transfer roller T2b and the support roller T2a can be adjusted individually. Thus, the parallelism between the secondary transfer roller T2b and the support roller T2a can be adjusted.

[0141] Furthermore, the secondary transfer unit Ut in Embodiment 1 is configured such that it can be removed from the copier U when the retraction mechanisms 34 to 39 are operating and the secondary transfer belt BTB is separated from the intermediate transfer belt B. Moreover, with the secondary transfer unit Ut removed, the fine-tuning mechanisms 42 to 46 at the front and rear of the secondary transfer unit Ut can be operated separately. Therefore, compared to the case where it cannot be removed from the copier U, it is easier to operate the fine-tuning mechanisms 42 to 46. Furthermore, the front fine-tuning mechanisms 42 to 46 can be operated simply by opening the front panel (not shown) of the copier U, even without removing the secondary transfer unit Ut from the copier U, while the rear fine-tuning mechanisms 42 to 46 can be operated with the secondary transfer unit Ut removed from the copier U. In particular, the secondary transfer unit Ut is positioned below the belt assembly BM in the direction of gravity, making it easy to view from above during operation. It also allows for the simultaneous inspection of the secondary transfer belt BTB while operating, and its shape, compared to the upward view, makes it easy to operate.

[0142] Furthermore, the secondary transfer unit Ut can also be configured as a non-removable structure. In this case, it can be configured without the rear fine-tuning mechanisms 42 to 46. That is, in Embodiment 1, adjustment can be made on both the front and rear sides, but it is not limited to this. For example, it can also be configured such that the rear side cannot be adjusted, that is, the interval between the secondary transfer roller T2b and the support roller T2a is fixed, and the parallelism is adjusted only on the front side relative to the rear side. However, compared with the case where adjustment can be made on both the front and rear sides, the adjustment range is more likely to be narrower, so it is preferable to make changes such as increasing the proportion of the outer diameter of the outer surface 42a and increasing the number of recesses 43a.

[0143] Here, in the structure described in Patent Document 1, a moving mechanism 100, equivalent to the fine-tuning mechanism 42 to fine-tuning mechanism 46 of Embodiment 1, is provided on the belt assembly side. That is, in Patent Document 1, the parallelism between the secondary transfer roller 154 and the support roller 165, as well as the movement control of the secondary transfer belt 153, are adjusted by adjusting the support roller 165 on the opposing intermediate transfer belt 151 side. The movement of the secondary transfer belt 153 is also related to the parallelism between the secondary transfer roller 154 and the peeling roller 155 on which the secondary transfer belt 153 is mounted. Therefore, there is a situation where the adjustment of the parallelism of the support roller 165 and the movement control are contradictory, and there is a situation where if the parallelism or the movement improves, the other deteriorates. In addition, when adjusting the movement of the secondary transfer belt 153 using the support roller 165, if the contact state of the secondary transfer belt 153 changes, the movement adjustment is also easily affected. Therefore, in the structure described in Patent Document 1, it is difficult to adjust the movement if the contact pressure of the secondary transfer area is adjusted on the secondary transfer belt 153 side. Therefore, in commercially available image forming apparatuses, in the moving mechanism 100, the support roller 165 can move not only in the horizontal direction, but also in the direction of approaching and separating from the secondary transfer roller 154, thereby providing a parallelism adjustment mechanism and a contact pressure adjustment mechanism on the belt assembly side.

[0144] However, incorporating parallelism adjustment mechanisms and contact pressure adjustment mechanisms into the components increases structural complexity. Furthermore, adjusting one aspect during parallelism and contact pressure adjustments will affect the other, making it difficult to improve the accuracy of these adjustments.

[0145] In contrast, in Embodiment 1, the load between the support roller T2a and the secondary transfer roller T2b can be adjusted using the load adjustment mechanisms 7 to 11 provided on the belt assembly BM side, and the parallelism between the support roller T2a and the secondary transfer roller T2b can be adjusted using the fine-tuning mechanisms 42 to 46 provided on the secondary transfer unit Ut side. Therefore, load adjustment and parallelism adjustment can be performed independently, and adjustment of one side does not easily affect the other. Thus, compared to a structure where the load adjustment mechanisms 7 to 11 and the fine-tuning mechanisms 42 to 46 are provided on the belt assembly BM, parallelism adjustment and load adjustment can be performed with high precision.

[0146] In particular, in Embodiment 1, the switching cam 7 is coaxially arranged with the support roller T2a. As described in Patent Document 1, when the guide elongated hole 104d of the support plate 101 is far from the support roller 165 to be adjusted, the effects of part errors and assembly errors are more likely to increase. However, in Embodiment 1, they are located coaxially and close to each other. As a result, the adjustment accuracy of the load is easily improved.

[0147] Similarly, in Embodiment 1, the fine-tuning cam 42 is coaxially arranged with the secondary transfer roller T2b. Therefore, compared to the case where the fine-tuning cam 42 is positioned far from the secondary transfer roller T2b, it is easier to improve the parallelism adjustment accuracy.

[0148] Furthermore, a secondary transfer belt (BTB) was used in Example 1. Therefore, compared to the case without the secondary transfer belt (BTB), the posture of the paper S recorded in the secondary transfer area Q4 is more easily stabilized, suppressing the occurrence of transfer defects. In particular, by utilizing the fine-tuning mechanisms 42 to 46 arranged on the secondary transfer unit Ut side, the parallelism of the secondary transfer roller T2b can be adjusted with good precision, thereby facilitating stable transport on the secondary transfer belt (BTB).

[0149] Furthermore, in Embodiment 1, a travel adjustment mechanism 51 is provided on the secondary transfer belt BTB. In the travel adjustment mechanism 51 of Embodiment 1, when the secondary transfer belt BTB snakes or deviates, the deviation is suppressed by tilting the driven shaft 31a in the direction of eliminating the deviation. Specifically, when the travel adjustment cam 59 rotates with the screws 57 loose, the adjustment plate 52 moves, and the driven shaft 31a supported by the adjustment plate 52 moves. By adjusting the relative position of the adjustment plate 52 by adjusting the positions of the front and rear adjustment plates 52 respectively, the driven roller 31 can be tilted in the target direction. Furthermore, if the screws 57 are tightened, the position of the driven roller 31 is fixed. Thus, in the travel adjustment mechanism 51 of Embodiment 1, the inclination of the driven shaft 31a can be adjusted, and snakes and deviations of the secondary transfer belt BTB in the width direction can be suppressed.

[0150] Here, compared to the structure described in Patent Document 1, which uses a single moving mechanism 100 to perform parallelism adjustment and travel adjustment, in Embodiment 1, fine-tuning mechanisms 42-46 and travel adjustment mechanism 51 can be performed independently and individually. In Embodiment 1, the travel adjustment mechanism 51 is located at a different position than the secondary transfer area Q4 where the fine-tuning mechanisms 42-46 for parallelism adjustment are located. Therefore, compared to Patent Document 1, which is concerned about the conflict between parallelism adjustment and travel adjustment, the parallelism adjustment of the secondary transfer roller T2b and the travel adjustment of the secondary transfer belt BTB can be reliably performed.

[0151] Furthermore, in Embodiment 1, the fine-tuning cam 42 remains in a state where the top end 44a of the stop lever 44 is embedded in the recess 43a. When the user is not operating the device, the fine-tuning cam 42 does not rotate and remains stationary. When the fine-tuning cam 42 rotates, the spring 46 contracts, and the stop lever 44 moves to an adjacent recess 43a in a protruding form that crosses the gap between the recesses 43a. The spring 46 then elastically returns to its original position, and the stop lever 44 is embedded in the adjacent recess 43a. Thus, the user can easily perceive the movement of the recess 43a by the resistance when the spring contracts as the fine-tuning cam 42 rotates and the clicking sound produced when the stop lever 44 is embedded in the adjacent recess 43a. Therefore, operability is improved compared to a structure without recesses 43a and a stop lever 44.

[0152] In Embodiment 1, the lower secondary transfer belt BTB has lower rigidity and hardness compared to the upper intermediate transfer belt B. Therefore, for example, when offsets occur in opposite directions within the secondary transfer area Q4 where the secondary transfer belt BTB contacts the intermediate transfer belt B, the less rigid secondary transfer belt BTB is more prone to positional deviation. Consequently, the secondary transfer belt BTB requires more fine-tuning. Therefore, compared to the case where fine-tuning mechanisms 42 to 46 are located on the belt assembly BM side, Embodiment 1, with its mechanisms located on the secondary transfer unit Ut side, more effectively handles positional deviations.

[0153] (Example of Change)

[0154] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments, and various modifications can be made within the scope of the spirit of the present invention as set forth in the claims. The following are examples of modifications (H01) to (H011) of the present invention.

[0155] (H01) In the embodiment described above, a copier U is shown as an example of an image forming apparatus, but it is not limited thereto. It can be applied to a fax machine or a multifunction machine that has multiple functions such as a fax machine, printer, or copier. In addition, it is not limited to a multicolor image forming apparatus, but may also include a monochrome image forming apparatus, i.e., a black and white image forming apparatus.

[0156] (H02) In the embodiments described, the specific values ​​illustrated may be appropriately changed to correspond to changes in design or specifications.

[0157] (H03) In the embodiment described above, a structure is shown in which the load adjustment mechanism 7 to the load adjustment mechanism 11 is disposed on the support roller T2a side, and the fine adjustment mechanism 42 to the fine adjustment mechanism 46 is disposed on the secondary transfer roller T2b side, but it is not limited to this. The load adjustment mechanism 7 to the load adjustment mechanism 11 may also be disposed on the secondary transfer roller T2b side, and the fine adjustment mechanism 42 to the fine adjustment mechanism 46 may be disposed on the support roller T2a side.

[0158] (H04) In the described embodiment, a structure with a secondary transfer belt BTB is preferred, but load adjustment mechanism 7 to load adjustment mechanism 11 and fine adjustment mechanism 42 to fine adjustment mechanism 46 may also be applied in a structure without a secondary transfer belt BTB. Furthermore, in a structure without a secondary transfer belt BTB, a travel adjustment mechanism 51 is not required.

[0159] (H05) In the embodiment described above, in the structure with secondary transfer belt BTB, it is ideal to provide a walking adjustment mechanism 51, but it is not impossible to use fine adjustment mechanisms 42 to 46 instead of providing a walking adjustment mechanism 51.

[0160] (H06) In the embodiment described above, a structure is illustrated in which load adjustment mechanism 7 to load adjustment mechanism 11 and fine adjustment mechanism 42 to fine adjustment mechanism 46 are applied at the contact area between the intermediate transfer belt B and the secondary transfer belt BTB, but it is not limited thereto. For example, it can be applied between two components where load adjustment and parallelism adjustment are desired, such as the contact area between the photosensitive belt and the intermediate transfer belt, the contact area between a pair of fixing belts, the contact area between a pair of transport belts, and the area where the photosensitive drum and the intermediate transfer belt face each other.

[0161] (H07) In the embodiment described above, a structure is shown in which the load adjustment mechanism 7 to the load adjustment mechanism 11 moves the front and rear ends of the support roller T2a simultaneously using the transmission shaft 10, but this is not a limitation. Individual mechanisms may also be used to move the front and rear ends of the support roller T2a. Ideally, the mechanisms on both sides should move in tandem, but mechanisms with time lag may also be used.

[0162] (H08) In the embodiments described above, the load adjustment mechanisms 7 to 11 are illustrated using a switching cam 7, but the embodiments are not limited to this. Instead of an eccentric cam, a structure such as a motor and gears, or a solenoid and spring, may be used. Furthermore, the structure is not limited to the relative positions of the adjustment shafts; instead, it may be designed to adjust the load by changing the elastic deformation of a pressed helical spring. Moreover, an eccentric cam makes the structure simpler and reduces manufacturing costs.

[0163] In addition, the fine-tuning mechanism 42 to fine-tuning mechanism 46 also use fine-tuning cam 42, but it can also be changed to motor and gear, etc.

[0164] (H09) In the embodiment described above, the walking adjustment mechanism 51 is shown to move the driven roller 31 generally in the vertical direction, but it is not limited to this. It may also be configured to move the driven roller 31 generally in the horizontal direction.

[0165] (H010) In the described embodiment, it is ideal to construct the secondary transfer belt BTB from a rubber belt with lower rigidity than the intermediate transfer belt B, but this is not a limitation. It may also be constructed from the same material as the intermediate transfer belt B, or from a material with higher rigidity than the intermediate transfer belt B.

[0166] (H011) In the embodiment described, a structure is illustrated with the tape component BM arranged on the upper side and the secondary transfer unit Ut arranged on the lower side, but it is not limited to this. It can also be applied to a structure in which the upper and lower sides are arranged oppositely, or in a structure in which the tape component BM and the secondary transfer unit Ut are arranged in a horizontal direction.

Claims

1. An image forming apparatus characterized by comprising: including: a first unit having a ring-shaped first belt member and a first rotating member that supports the first belt member and rotates; a second unit having a second rotating member that is disposed opposite the first rotating member with the first belt member interposed therebetween and is rotatable; a first adjustment member provided in one of the first unit and the second unit and adjusting a load between the first rotating member and the second rotating member in accordance with a thickness of a medium on which an image is recorded; and a second adjustment member provided in the other of the first unit and the second unit and adjusting parallelism between the first rotating member and the second rotating member in accordance with a positional relationship therebetween.

2. The image forming apparatus according to claim 1, characterized by, including: the second unit having a ring-shaped second belt member that is supported by the second rotating member and rotates.

3. The image forming apparatus according to claim 2, characterized by, including: the second unit having a suppression member that suppresses a shift of the second belt member in a width direction.

4. The image forming apparatus according to claim 2 or 3, characterized by including: the first belt member retaining an image on a surface; and the second belt member conveying the image while transferring the image from the surface of the first belt member to a medium.

5. The image forming apparatus according to any one of claims 1 to 3, characterized by, including: the first adjustment member adjusting positions of both ends of a rotation axis of one of the first rotating member and the second rotating member, thereby adjusting the load, with respect to the one rotating member.

6. The image forming apparatus according to claim 5, characterized by, including: the first adjustment member including a first eccentric member that supports both ends of a rotation axis of the one rotating member and adjusts a distance from the second unit with rotation of the first eccentric member, thereby adjusting the positions of both ends of the rotation axis.

7. The image forming apparatus according to any one of claims 1 to 3, characterized by, including: the second adjustment member adjusting a position of a single-side end of a rotation axis of the other rotating member, thereby adjusting the parallelism, with respect to the other rotating member.

8. The image forming apparatus according to claim 7, characterized by, including: the second adjustment member including a second eccentric member that supports the rotation axis of the other rotating member and adjusts a distance of the single-side end of the rotation axis of the other rotating member from the first unit with rotation of the second eccentric member, thereby adjusting the position of the single-side end.

9. The image forming apparatus according to claim 1, characterized by, including: the first adjustment member is provided in the first unit; and the second adjustment member is provided in the second unit.

10. The image forming apparatus according to claim 9, characterized in that, including: the first adjustment member adjusts the load by adjusting a distance from the second unit; and the second adjustment member adjusts the parallelism by adjusting a distance from the first unit, and an amount of adjustment of the distance of the second adjustment member is smaller than that of the first adjustment member.

11. The image forming apparatus according to claim 10, characterized in that, including: the second unit is disposed on a lower side of the first unit in a direction of gravity and is detachably provided with respect to a main body of the image forming apparatus.

12. The image forming apparatus according to claim 10 or 11, characterized by, including: The second unit has a second belt member that is a ring-shaped second belt member supported by and rotated by the second rotating member, and has lower rigidity than the first belt member of the first unit.

Images