Fixing device and image forming apparatus
The fixing device design with a biased second cleaning member and protrusion on the opposing member prevents bending, ensuring effective cleaning by maintaining contact pressure and reducing wear, thereby enhancing cleaning efficiency and lifespan.
Patent Information
- Application Number
- JP2024114777
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-18
- Publication Date
- 2026-01-29
AI Technical Summary
The cleaning member in fixing devices bends when it comes into contact with the rotating body, leading to poor cleaning performance.
A fixing device design that includes a first cleaning member and a second cleaning member, where the second member is biased to contact the first member from a direction that counters the bending caused by the rotating body, and a protrusion on the opposing member is positioned to prevent bending, along with a refreshing roller to maintain effective cleaning.
Prevents bending of the cleaning member, ensuring effective cleaning performance by maintaining contact pressure and reducing wear, thus enhancing the lifespan and efficiency of the cleaning process.
Smart Images
Figure 2026013974000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a fixing device of an image forming apparatus, and more particularly to the configuration of a fixing device equipped with a circular belt. [Background technology]
[0002] 2. Description of the Related Art Conventionally, fixing devices have been known that have a cleaning member capable of cleaning a rotating body. (See, for example, Patent Document 1). [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 2-51369 (page 5, Figure 1) Summary of the Invention [Problem to be solved by the invention]
[0004] However, there is a problem in that the cleaning member may bend when it comes into contact with the rotating body, resulting in poor cleaning. An object of the present invention is to provide a fixing device that can prevent poor cleaning. [Means for solving the problem]
[0005] The fixing device according to the present invention comprises: a rotating body extending in a first direction; a first cleaning member extending in the first direction and contacting the rotating body to clean it; a second cleaning member extending in the first direction and contacting the first cleaning member to clean it; and a biasing mechanism biasing the first cleaning member in a second direction toward the rotating body; a fixing device characterized in that, when a direction from the rotation shaft of the second cleaning member toward the rotation shaft of the first cleaning member is defined as a third direction, the third direction crosses the second direction from the downstream side to the upstream side in the rotation direction of the rotating body. [Effects of the Invention]
[0006] According to the fixing device of the present invention, it is possible to prevent the cleaning member from bending due to contact with the rotating body, and thus prevent poor cleaning. [Brief explanation of the drawings]
[0007] [Figure 1] 1 is a diagram showing a configuration of a main part of an image forming apparatus according to a first embodiment of the present invention; [Figure 2] 1 is a diagram showing the configuration of a main part of a fixing device according to a first embodiment of the present invention; [Figure 3] FIG. 2 is a perspective view of the fixing belt unit together with the pressure roller, seen from diagonally above. [Figure 4] 4 is a cross-sectional view of a main part of the fixing belt unit shown in FIG. 3, taken at the center in the longitudinal direction (Y direction), as viewed from the left side. FIG. [Figure 5] 10A and 10B are diagrams showing the configuration of the right guide member alone, in which (a) is a rear view and (b) is an external perspective view seen from diagonally above. [Figure 6] FIG. 5 is a partially enlarged view of the opposing member shown in FIG. 4 to explain its configuration and its positional relationship with the right guide member and heater unit, and further shows its positional relationship with the cleaning roller and the refreshing roller, which are indicated by dotted lines. [Figure 7] 6. FIG. 7 is an external perspective view of the right support lever, right guide member, heater unit, and opposing member shown in FIG. 4, together with the left support lever, left guide member, and electrical connector connection portion, as viewed from the direction of arrow C (rear and lower) shown in FIGS. [Figure 8] 5 is a cross-sectional view of a main part of a fixing belt unit employed in a fixing device according to a second embodiment of the present invention, shown under the same conditions as the cross-sectional view of the main part of FIG. 4 in the first embodiment. FIG. [Figure 9] FIG. 2 is a perspective view of the fixing belt unit together with the pressure roller, seen from diagonally above. [Figure 10] 5 is a cross-sectional view of a main part of a fixing belt unit employed in a fixing device according to a third embodiment of the present invention, shown under the same conditions as the cross-sectional view of the main part of FIG. 4 in the first embodiment. FIG. [Figure 11] 1A and 1B are schematic explanatory diagrams, in which FIG. 1A is a schematic explanatory diagram showing the configuration of the first embodiment, and FIG. 1B is a schematic explanatory diagram showing the configuration of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION
[0008] Embodiment 1 FIG. 1 is a diagram showing the configuration of a main part of an image forming apparatus 11 according to a first embodiment of the present invention.
[0009] Image forming device 11 has a configuration as, for example, an electrophotographic, direct transfer color printer, and four independent image forming units 12C, 12M, 12Y, and 12K (sometimes referred to as image forming units 12 when no particular distinction is required) are detachably arranged in order from the upstream side along the conveyance direction (direction of arrow A) of recording paper 22. Image forming unit 12C forms a cyan (C) image, image forming unit 12M forms a magenta (M) image, image forming unit 12Y forms a yellow (Y) image, and image forming unit 12K forms a black (K) image.
[0010] In this embodiment, the configurations of these image forming units 12C, 12M, 12Y, and 12K are identical, and only the color of the toner contained therein differs. Therefore, the internal structure of the cyan (C) image forming unit 12C will be described below as an example.
[0011] The image forming unit 12C includes a photosensitive drum 13C (sometimes simply referred to as photosensitive drum 13 when there is no need to distinguish between them), a charging roller 14C (sometimes simply referred to as charging roller 14 when there is no need to distinguish between them) that uniformly charges the surface of the photosensitive drum 13C, and a developing device 16C (sometimes simply referred to as developing device 16 when there is no need to distinguish between them) that forms a toner image by adhering cyan toner to the electrostatic latent image formed on the surface of the photosensitive drum 13C.
[0012] An exposure head 15C (sometimes simply referred to as exposure head 15 when no particular distinction is required) is disposed above photoreceptor drum 13C in a position facing photoreceptor drum 13C. Similarly, corresponding exposure heads 15M, 15Y, and 15K are disposed for the other photoreceptor drums 13M, 13Y, and 13K, respectively. The exposure heads 15 selectively expose the photoreceptor drum 13 to light in accordance with image data for the corresponding color, forming an electrostatic latent image on the surface.
[0013] A transfer unit 21 is disposed below each photosensitive drum 13 of the four image forming units 12. The transfer unit 21 includes transfer rollers 17C, 17M, 17Y, and 17K (which may be simply referred to as transfer rollers 17 when no particular distinction is required), and a transfer belt 20 that is stretched and arranged to be able to run in the direction of arrow A in FIG.
[0014] Each transfer roller 17 is positioned in pressure contact with the corresponding photosensitive drum 13 via the transfer belt 20, and in the nip formed by the pressure, the recording paper 22 transported by the transfer belt 20 is charged to a polarity opposite to that of the toner, and the toner images of each color formed on the corresponding photosensitive drum 13 are transferred sequentially onto the recording paper 22 in layers.
[0015] A paper feed mechanism for feeding recording paper 22 to transfer belt 20 is disposed below transfer unit 21 of image forming device 11. The paper feed mechanism includes a support plate 35 on which recording paper 22 is placed, a hopping roller 24 that picks up recording paper 22 and discharges it onto paper transport path 45, a biasing spring 36 that presses support plate 35 to press the top of recording paper 22 placed on support plate 35 against hopping roller 24, a first transport roller pair 25 and a second transport roller pair 26 that transport the picked-up recording paper 22 along paper transport path 45 to transfer belt 20, etc.
[0016] A fixing device 40 is provided on the discharge side of the recording paper 22 from the transfer belt 20. The fixing device 40 has a fixing belt unit 41 and a pressure roller 42, and fixes the toner transferred onto the recording paper 22 by applying heat and pressure. On the discharge side of the fixing device 40, a pair of discharge rollers 27, 28 are arranged along a paper transport path 45, and the printed recording paper 22 discharged from the fixing device 40 is discharged along the paper transport path 45 to a paper stacker unit 46. The fixing device 40 will be described in detail later.
[0017] The photosensitive drum 13, hopping roller 24, first conveying roller pair 25, second conveying roller pair 26, transfer belt drive roller 18, and discharge roller pair 27, 28 are rotated by a drive means including a motor or the like.
[0018] 1, the X-, Y-, and Z-directions are defined as the conveyance direction (direction of arrow A) of the recording paper 22 as it passes through the image forming units 12C, 12M, 12Y, and 12K, the Y-direction is the direction of the rotation axis of each photosensitive drum 13, and the Z-direction is the direction perpendicular to both of these directions. Furthermore, when the X-, Y-, and Z-directions are shown in other figures described later, these directions refer to the same directions. That is, the X-, Y-, and Z-directions in each figure indicate the arrangement direction when the depicted parts of each figure constitute the image forming apparatus 11 shown in FIG. 1. Here, the Z-direction is assumed to be approximately vertical.
[0019] 2 is a diagram showing the essential configuration of fixing device 40 according to the first embodiment of the present invention, and Fig. 3 is an external perspective view of fixing belt unit 41 together with pressure roller 42, viewed obliquely from above. Note that the fixing device 40 may be identified as having top (positive direction of the Z axis), bottom, left, right, front, and rear when viewed from the direction of arrow A (Fig. 1), which is the conveying direction of recording paper 22 by transfer belt 20.
[0020] As shown in these figures, fixing device 40 is arranged such that pressure roller 42 and fixing belt unit 41, which is located above pressure roller 42 and has fixing belt 104, an endless belt member serving as a rotating body, are both extended in the Y direction. Fixing belt unit 41 is arranged with heater unit 105, which extends in the Y direction and heats fixing belt 104 from the inside, inside fixing belt 104. The Y direction, which is the first direction in which fixing belt unit 41 extends, may also be referred to as the longitudinal direction or the width direction of recording paper 22.
[0021] The pressure roller 42 has both ends of its rotation shaft 42a rotatably supported by a right side plate 101R and a left side plate 101L (not shown) disposed symmetrically thereto of the frame 100 of the fixing device 40, and is driven to rotate in the direction of the arrow (counterclockwise) by an external rotational driving force. The frame 100 integrally includes the right side plate 101R and the left side plate 101L (not shown), and holds the components of the fixing device 40, such as the pressure roller 42 and the fixing belt unit 41, in place.
[0022] The heater unit 105 has a flat portion 105a at its bottom that transfers heat to the fixing belt 104, and is disposed so as to be in pressure contact with the elastic peripheral surface of the pressure roller 42 via the fixing belt 104, forming a nip portion 150. When the pressure roller 42 rotates in the direction of the arrow in this state, the fixing belt 104 also rotates together.
[0023] At this time, the left and right ends of the fixing belt 104 are guided by the right guide member 111R and the left guide member 111L, and the fixing belt 104 rotates clockwise following the rotation of the pressure roller 42. The configuration of the guide members 111 will be described in detail later. Note that the movement of the fixing belt 104 rotating on its own axis while moving at this time may be referred to as rotational movement.
[0024] As described above, the recording paper 22 after transfer passes through the nip portion 150 in the direction of the dotted arrow B, and the transferred toner image is fixed by the heat and pressure treatment that the recording paper 22 receives while passing through the nip portion 150, and the recording paper 22 is then discharged from the fixing device 40.
[0025] Next, the configuration of the fixing belt unit 41 that rotatably supports the fixing belt 104 and disposes the heater unit 105 inside the fixing belt 104 will be further described.
[0026] 4 is a cross-sectional view of the fixing belt unit 41 shown in FIG. 3, taken at the center in the longitudinal direction (Y direction), as viewed from the left side. The figure also shows the pressure roller 42 when cut at the same position.
[0027] 4, the fixing belt unit 41 has a right rotation shaft hole 110R formed at the lower end of the right support lever 103R, into which the right rotation fulcrum 107R (FIG. 2) of the right side plate 101R fits. As a result, the right side of the fixing belt unit 41 is rotatably held by the right side plate 101R.
[0028] As will be described later, the right support lever 103R also includes a right guide member 111R that rotatably supports the right end of the fixing belt 104, and further fixedly supports the right end of the heater unit 105 that is disposed inside the fixing belt 104. Therefore, the right support lever 103R, the right guide member 111R, and the right end of the heater unit 105 are integrally configured.
[0029] 5A and 5B are diagrams showing the configuration of the right guide member 111R alone, with FIG. 5A being a rear view and FIG. 5B being an external perspective view seen from diagonally above.
[0030] As shown in these figures, the right guide member 111R as a flange member has an outer peripheral surface formed in a substantially arc-shaped cross section, and is located inside the right end portion of the fixing belt 104 as shown in FIG. 4. It is equipped with an inner guide portion 113R that guides the inside of the fixing belt 104, and a right regulating portion 112R as a flange portion that abuts against the right end portion of the fixing belt 104 and regulates its movement in the right direction (-Y direction).
[0031] FIG. 6 is a partially enlarged view of the opposing member 123 shown in FIG. 4 to explain the configuration of the opposing member 123 and the positional relationship with the right guide member 111R and heater unit 105, and further shows the positional relationship with the cleaning roller 121 and the refreshing roller 122, which are indicated by dotted lines.
[0032] As shown in Figures 4 and 6, the opposing member 123 is attached to the outer casing of the heater unit 105, which extends longitudinally inside the fixing belt 104, and consists of an attachment portion 123a facing the top surface of the outer casing, and a guide portion 123b that continues from the top surface to the back surface and faces the attachment portion 123a, and is formed with a width that covers the area through which the recording paper 22 passes.
[0033] 6, when viewed from the longitudinal direction (Y direction), the surface of this guide portion 123b has a belt sliding surface 123c that is formed substantially flush with a right guide surface 114R serving as a support surface having a substantially arcuate cross section of the inner guide portion 113R of the right guide member 111R and on which the fixing belt 104 slides, and a belt introduction surface 123d that is formed continuously with the belt sliding surface 123c and is retracted inward so as to be spaced apart from the fixing belt 104. A protrusion 125 is formed on the end of the belt sliding surface 123c in the rotational movement direction of the fixing belt 104 (corresponding to the rotation direction of the rotating body, the direction of arrow E).
[0034] 7 is an external perspective view of the right support lever 103R, right guide member 111R, heater unit 105, and opposing member 123 shown in FIG. 4, together with the left support lever 103L, left guide member 111L, and electrical connector connection portion 160, as viewed from the direction of arrow C (rear and lower) shown in FIGS. 4 and 6.
[0035] As shown in the figure, the protruding portion 125 of the opposing member 123 is configured so that the amount of protrusion increases toward the center in the longitudinal direction (Y direction) of the opposing member 123. That is, the end of the protruding portion 125 facing the right guide member 111R is formed to be approximately flush with the right guide surface 114R (shown by a dotted line in FIG. 6) of the right guide member 111R, and the height gradually increases toward the center (see center line C), forming a protruding shape that is highest at or near the center, which corresponds to the intermediate portion, such as a crown shape. Here, the maximum amount of protrusion of the center relative to the end is defined as t.
[0036] The maximum protrusion amount t here is 0 [mm] <t≦1[mm] The reason for providing the protruding portion 125 on the opposing member 123 will be explained later. The direction of the arrow C shown in FIGS. 4 and 6 is the viewing angle direction in which the maximum protrusion amount t can be shown.
[0037] As shown in Figures 2, 3, 4, etc., the fixing belt unit 41 further includes a cleaning roller 121 as a first cleaning member and a refreshing roller 122 as a second cleaning member, which extend parallel to the opposing member 123 in the longitudinal direction (Y direction).
[0038] 3 and 4, the right roller shaft holder 126R as a shaft holder rotatably holds the right end of the rotation shaft of the cleaning roller 121, and also rotatably holds the right end of the rotation shaft of the refreshing roller 122 while maintaining a predetermined axis spacing, as will be described later. The right roller shaft holder 126R is shaded in Fig. 4 to clearly show its location.
[0039] The right support lever 103R, right guide member 111R, right roller shaft holder 126R, and right end portions of the heater unit 105 and opposing member 123, including the right side plate 101R (FIG. 2), are configured in the same manner at the left end portion of the fixing belt unit 41. That is, these are formed approximately symmetrically with respect to an imaginary center plane that intersects perpendicularly at the center of the fixing belt unit 41 in the longitudinal direction (Y direction) excluding the electrical connector connection portion 160 (FIG. 3).
[0040] Furthermore, to distinguish between left and right, the reference numerals of components arranged symmetrically at the left and right ends are suffixed with (L) and (R), for example, left support lever 103L and right support lever 103R, but when no particular distinction is required, these suffixes may be omitted and the component may be referred to as support lever 103. Furthermore, for the components arranged symmetrically at the left and right ends of fixing belt unit 41, the configuration of the right end will mainly be described, and the left end will also be mentioned as necessary.
[0041] The distance between the pair of shafts of the right roller shaft holder 126R is determined so that the cleaning roller 121 and the refreshing roller 122 come into contact with each other and form a predetermined nip portion, as shown in Fig. 4. Furthermore, the right roller shaft holder 126R is held by the right support lever 103R through a right guide hole 116R formed in the right support lever 103R so as to be movable in parallel in the direction in which the cleaning roller 121 moves toward and away from the opposing member 123.
[0042] That is, the right roller shaft holder 126R is held by the right support lever 103R so as to be movable in parallel along an imaginary movement axis 500 indicated by a dashed line in Fig. 6, and is further urged in the direction of arrow D, which is a second direction that is a parallel movement direction, by a right compression spring 127R serving as a first urging member stretched between the right support lever 103R and the right roller shaft holder 126R, so that the cleaning roller 121 is configured to come into pressure contact with the belt sliding surface 123c (Fig. 6) of the opposing member 123 via the fixing belt 104. The parallel movement direction here is a direction in which the cleaning roller 121 approaches the belt sliding surface 123c and can come into pressure contact with it. In this case, the roller shaft holder 126, the guide hole 116, and the compression spring 127 correspond to a biasing mechanism.
[0043] Here, it is assumed that the imaginary movement axis 500 is perpendicular to the imaginary tangent line 501 at the position where the belt sliding surface 123c of the opposing member 123 and the cleaning roller 121 come into contact with each other.
[0044] Furthermore, the right roller shaft holder 126R is configured to move parallel to the cleaning roller 121 while maintaining a state in which its inter-axial direction (the direction connecting the rotational shafts of the cleaning roller 121 and the refreshing roller 122 at the shortest distance) is inclined by an adjustment angle θ with respect to the parallel movement direction (the extension direction of the imaginary movement axis 500), as shown in FIG. 6. The inclined direction here is the direction in which the refreshing roller 122 is located downstream of the imaginary movement axis 500 in the rotational movement direction (the direction of arrow E) of the fixing belt 104. Therefore, the refreshing roller 122 maintains a state in which it is pressed against the cleaning roller 121 from the direction of arrow F, which is a third direction inclined by the adjustment angle θ from the imaginary movement axis 500.
[0045] The fixing belt unit 41 configured as described above is supported on both the left and right sides by the pivot points 107 formed on the frame body 100 so that it can rotate freely on the same axis, as described above, and is biased in the direction of arrow A by a compression spring (not shown) suspended between the side plate 101 and the spring receiving portion 130 (Figure 4).
[0046] This biasing force causes the flat portion 105a of the heater unit 105 to come into pressure contact with the pressure roller 42 via the fixing belt 104, forming a nip portion 150 (FIG. 2). When separating the fixing belt 104 from the pressure roller 42, a cam (not shown) or the like presses the flat contact portion 131 (FIG. 4), rotating the fixing belt unit 41 clockwise to separate them.
[0047] 2, with nip 150 formed, pressure roller 42 rotates in the direction of the arrow (counterclockwise), causing fixing belt 104 to rotate together. In this state, when recording paper 22 on which transfer has been completed passes through nip 150 in the direction of arrow B, the transferred toner image is fixed by the heat (by fixing belt 104 heated to a predetermined temperature) and pressure treatment that it receives during this passage, and the recording paper is discharged from fixing device 40.
[0048] 2, downstream of the nip portion 150 in the rotational movement direction of the fixing belt 104, a cleaning roller 121 is disposed, which is in pressure contact with the belt sliding surface 123c (FIG. 6) of the opposing member 123 via the fixing belt 104. The cleaning roller 121 rotates counterclockwise in accordance with the rotational movement of the fixing belt 104, and the refreshing roller 122, which is in pressure contact with the cleaning roller 121 and rotates clockwise.
[0049] By these rotations, the cleaning roller 121 removes the developer adhering to the fixing belt 104 during fixing, and the refreshing roller 122 removes the developer adhering to the cleaning roller 121. Therefore, the fixing belt 104 heated in the nip portion 150 comes into direct contact with the cleaning roller 121 while still at a high temperature, so that the removal process can be carried out efficiently. Therefore, the opposing member 123 is formed in an area including the position where the outer circumferential surface of the fixing belt 104, which has passed through the nip portion 150, first comes into contact with the cleaning roller 121.
[0050] Here, the reasons for providing the protruding portion 125 on the opposing member 123 and for pressing the refreshing roller 122 against the cleaning roller 121 at an adjustment angle θ will be explained.
[0051] 4, when the cleaning roller 121, which is in pressure contact with the fixing belt 104, rotates counterclockwise in accordance with the rotational movement of the fixing belt 104 in the direction of arrow E, it receives a downstream biasing force due to frictional force generated by the shaft, etc. This causes the cleaning roller 121 to bend so that the center of the cleaning roller 121 protrudes downstream more than the ends in the width direction.
[0052] 6, the protruding portion 125 of the opposing member 123 is located downstream of the cleaning roller 121 and acts to suppress this bending. As described above, the maximum protruding amount t is set to 1 mm or less in order to suppress damage and shortening of the lifespan of the fixing belt 104 due to the increased pressing force between the protruding portion and the cleaning roller 121 on the fixing belt 104 as the protruding portion protrudes more.
[0053] Furthermore, the refreshing roller 122 contacts the cleaning roller 121 from the downstream side in the rotational movement direction of the fixing belt 104, thereby pressing the cleaning roller 121 from the direction opposite to the direction in which the cleaning roller 121 tends to bend, thereby acting to suppress this bending. Therefore, the rotation axis of the refreshing roller 122 is disposed so as to be located downstream in the rotational movement direction (direction of arrow E) of the fixing belt 104 from an imaginary movement axis 500 perpendicular to an imaginary tangent line 501 in FIG.
[0054] Here, the adjustment angle θ is set as follows when the diameter of the cleaning roller 121 is set to 11 mm or more: 3°≦θ<90° When the diameter of the cleaning roller 121 is set to 8 mm or more and less than 11 mm, 5°≦θ<90° Let's say. In this first embodiment, the diameter of the cleaning roller 121 is set to 11 mm, and the adjustment angle θ is set to 3.8°.
[0055] As the diameter of the cleaning roller 121 increases, the rigidity increases, so that deflection can be sufficiently suppressed even if the adjustment angle θ is made small.
[0056] Here, the imaginary movement axis 500, which is the parallel movement direction of the right roller shaft holder 126R, is set in a direction perpendicular to the imaginary tangent 501 at the position where the belt sliding surface 123c of the opposing member 123 and the cleaning roller 121 contact, but this is not limited to this and may be set in any appropriate direction as appropriate.
[0057] As described above, according to the fixing device 40 of the present embodiment 1, the bending of the cleaning roller 121 can be suppressed by the refreshing roller 122 that presses against the cleaning roller 121 from a direction that suppresses the bending of the cleaning roller 121 that would otherwise occur due to the rotational movement of the fixing belt 104, and the protrusion 125 of the opposing member 123 that is formed in a position that prevents the bending.
[0058] Furthermore, the cleaning roller 121 can be a cylindrical roller with a smooth surface, such as a product drawn from a mold, so the problem of reduced cleaning performance due to polishing marks that occur when making it into a crown shape can be avoided.
[0059] Embodiment 2 Fig. 8 is a cross-sectional view of a main part of fixing belt unit 241 employed in a fixing device according to a second embodiment of the present invention, and is a cross-sectional view of a main part shown under the same conditions as the cross-sectional view of Fig. 4 in the first embodiment. Fig. 9 is an external perspective view of fixing belt unit 241 together with pressure roller 42, seen obliquely from above.
[0060] The main difference between the fixing belt unit 241 of this embodiment shown in the same figure and the fixing belt unit 41 of embodiment 1 shown in Figure 4, for example, is the configuration of the right roller shaft holder 226R (right roller shaft holder 126R in embodiment 1) that holds the rotation shafts of the cleaning roller 121 and the refreshing roller 122.
[0061] Therefore, parts of the fixing device employing this right roller shaft holder 226R that are common to the fixing device 40 (FIG. 2) of the first embodiment described above will be denoted by the same reference numerals or will not be shown in the drawings, and explanations will be omitted, with a focus on the differences. Since the essential configuration of the image forming device of this embodiment is common to the essential configuration of the image forming device 11 of the first embodiment shown in FIG. 1, except for the fixing device, reference will be made to FIG. 1 as necessary. Also, reference will be made to FIG. 6, as it is a common view.
[0062] 8, right roller shaft holder 226R as a shaft holder here rotatably holds the right end of the rotation shaft of cleaning roller 121, and is held by right guide hole 116R formed in right support lever 103R so as to be able to move in parallel along imaginary movement axis 500 shown by the dashed line in Fig. 6. Right compression spring 127R stretched between right support lever 103R and right roller shaft holder 226R biases right roller shaft holder 226R in the direction of arrow D, which is the direction of parallel movement, so that cleaning roller 121 is pressed against belt sliding surface 123c (Fig. 6) of opposing member 123 via fixing belt 104.
[0063] 6, the right roller shaft holder 226 is provided with a right sub-holder portion 228R that rotatably holds the right end portion of the rotation shaft of the refreshing roller 122 and slidably holds the right end portion of the rotation shaft of the refreshing roller 122 in a direction inclined by an adjustment angle θ with respect to the imaginary movement axis 500. The inclined direction here is the direction in which the refreshing roller 122 is located downstream of the imaginary movement axis 500 in the rotational movement direction of the fixing belt 104 (the direction of arrow E).
[0064] The right sub-holder portion 228R has a right compression spring 229R as a second biasing member therein, which biases the rotation shaft of the refreshing roller 122 toward the axial center of the cleaning roller 121. The right roller shaft holder 226R is shaded in the figure to clarify its location.
[0065] Therefore, the refreshing roller 122 comes into pressure contact with the cleaning roller 121 with a predetermined pressure from a direction inclined by the adjustment angle θ. In this case, the roller shaft holder 226, the guide hole 116, and the compression spring 127 correspond to a biasing mechanism.
[0066] As described above, according to the fixing device of the second embodiment, similar to the fixing device 40 of the first embodiment, the bending of the cleaning roller 121 can be suppressed by the refreshing roller 122 that presses against the cleaning roller 121 from a direction that suppresses the bending of the cleaning roller 121 that would otherwise occur due to the rotational movement of the fixing belt 104, and the protrusion 125 of the opposing member 123 that is formed in a position that prevents the bending.
[0067] Furthermore, in the configuration of embodiment 1, if wear occurs on the roller surface of the cleaning roller 121 or the refreshing roller 122, the diameter of each roller will become smaller while the axial distance between each roller remains fixed, which may result in a decrease in the pressing force of the refreshing roller 122 against the cleaning roller 121.
[0068] In contrast, in the configuration of embodiment 2, the refreshing roller 122 is constantly biased against the cleaning roller 121 by the compression spring 229, so even if wear occurs on the roller surface of the cleaning roller 121 or the refreshing roller 122 and the diameter of each roller becomes smaller, the reduction in the pressing force of the refreshing roller 122 against the cleaning roller 121 can be suppressed.
[0069] Embodiment 3 FIG. 10 is a cross-sectional view of a main part of a fixing belt unit 341 employed in a fixing device according to a third embodiment of the present invention, and is a cross-sectional view of a main part shown under the same conditions as the cross-sectional view of the main part in FIG. 4 according to the first embodiment.
[0070] The main difference between the fixing belt unit 341 of this embodiment shown in the same figure and the fixing belt unit 41 of embodiment 1 shown in Figure 4, for example, is that it is equipped with a first right shaft holder portion 326R that rotatably holds the rotation shaft of the cleaning roller 121 and holds it so that it can slide in a predetermined direction, and a second right shaft holder portion 330R that rotatably holds the rotation shaft of the refreshing roller 122 and holds it so that it can slide in a predetermined direction.
[0071] Therefore, parts of the fixing device employing the first right shaft holder portion 326R and the second right shaft holder portion 330R that are common to the fixing device 40 (FIG. 2) of the first embodiment described above will be denoted by the same reference numerals or will not be shown in the drawings, and explanations will be omitted, with a focus on the differences. Since the essential configuration of the image forming device of this embodiment is common to the essential configuration of the image forming device 11 of the first embodiment shown in FIG. 1, except for the fixing device, reference will be made to FIG. 1 as necessary. Also, reference will be made to FIG. 6, as it is a common view.
[0072] As shown in FIG. 10, the first right shaft holder portion 326R as the first holding portion is arranged on the right support lever 103R, and holds the rotation shaft of the cleaning roller 121 rotatably and slidably along the imaginary movement axis 500 shown in FIG. 6.
[0073] On the other hand, the second right shaft holder part 330R as a second holding part is disposed on the right support lever 103R separately from the first right shaft holder part 326R, and rotatably holds the rotation shaft of the refreshing roller 122, while also holding it slidably in a direction inclined by the adjustment angle θ with respect to the imaginary movement axis 500 shown in Fig. 6. The rotation shaft of the refreshing roller 122 is urged toward the axial center of the cleaning roller 121 by a right compression spring 329R as a third urging member disposed inside the second right shaft holder part 330R.
[0074] Here, differences between the fixing belt unit 41 of the first embodiment and the fixing belt unit 341 of the third embodiment will be described with reference to the schematic diagrams shown in Fig. 11. Fig. 11(a) is a schematic diagram showing the configuration of the first embodiment, and Fig. 11(b) is a schematic diagram showing the configuration of the third embodiment.
[0075] As shown in Fig. 1(a), in the first embodiment, the right roller shaft holder 126R rotatably holds the rotation shaft of the cleaning roller 121 and the rotation shaft of the refreshing roller 122 at a predetermined distance, and the right roller shaft holder 126R is held by the right support lever 103R so as to be movable in parallel along the imaginary movement axis 500 while keeping the inter-axial direction (the direction connecting the rotation shaft of the cleaning roller 121 and the rotation shaft of the refreshing roller 122 at the shortest distance) tilted by an adjustment angle θ with respect to the imaginary movement axis 500. For reference, in Fig. 1(a), the right roller shaft holder 126R, cleaning roller 121, and refreshing roller 122 are shown by dotted lines when moved in parallel to arbitrary positions.
[0076] For this reason, a right guide hole 116R that guides the guided portion of the right roller shaft holder 126R is formed in the right support lever 103R. The right roller shaft holder 126R is biased in the direction of arrow D by a right compression spring 127R (FIG. 4) that is stretched between the right support lever 103R and the right roller shaft holder 126R.
[0077] On the other hand, as shown in the same figure (b), in this embodiment 3, the right support lever 103R is equipped with a first right shaft holder portion 326R consisting of a first right bearing portion 351R that rotatably holds the rotation shaft of the cleaning roller 121 and a first right guide 352R that guides this first right bearing portion 351R along the imaginary movement axis 500.
[0078] The right support lever 103R is also provided with a second right shaft holder portion 330R, which consists of a second right bearing portion 353R that rotatably holds the rotating shaft of the refreshing roller 122, and a second right guide 354R that guides the second right bearing portion 353R along a direction inclined by an adjustment angle θ with respect to the imaginary movement axis 500 when the peripheral surface of the cleaning roller 121 is in contact with the fixing belt 104, and further includes a right compression spring 329R (Figure 10) that urges the second right bearing portion 353R toward the first right bearing portion 351R.
[0079] According to the above configuration, the right compression spring 329R presses the refreshing roller 122 against the cleaning roller 121 at the adjustment angle θ, and the cleaning roller 121 receives this pressing force and is pressed against the opposing member 123 via the fixing belt 104 in the direction of arrow D along the imaginary movement axis 500.
[0080] In this state, the cleaning roller 121 rotates counterclockwise in accordance with the rotational movement of the fixing belt 104 at this time, and the refreshing roller 122, which is in pressure contact with the cleaning roller 121 and driven by it, rotates clockwise. Due to these rotations, the cleaning roller 121 removes the developer that has adhered to the fixing belt 104 during fixing, and the refreshing roller 122 removes the developer that has adhered to the cleaning roller 121.
[0081] The adjustment angle θ here is set as follows in order to ensure a sufficient pressing force of the cleaning roller 121 in the direction of the arrow D: 5°<θ≦15° Let's say.
[0082] As described above, according to the fixing device of the third embodiment, similar to the fixing device 40 of the first embodiment, the bending of the cleaning roller 121 can be suppressed by the refreshing roller 122 that presses against the cleaning roller 121 from a direction that suppresses the bending of the cleaning roller 121 that would otherwise occur due to the rotational movement of the fixing belt 104, and the protrusion 125 of the opposing member 123 that is formed in a position that prevents the bending.
[0083] Furthermore, as in the fixing device of the second embodiment, the refreshing roller 122 is constantly biased against the cleaning roller 121 by the compression spring 329. Therefore, even if wear occurs on the roller surface of the cleaning roller 121 or the refreshing roller 122 and the diameter of each roller becomes smaller, the pressing force of the refreshing roller 122 against the cleaning roller 121, and further the pressing force of the cleaning roller 121 against the opposing member 123 via the fixing belt 104, can be prevented from decreasing.
[0084] Furthermore, since only the compression spring 329 is provided as the biasing member in this configuration, it is possible to obtain the same effects as those obtained in the first and second embodiments while suppressing the increase in size and cost of the device due to the increase in mechanical parts.
[0085] Furthermore, in the claims and the description of the embodiments, terms such as "upper," "lower," "left," "right," "front," and "rear" are used for convenience only and do not limit the absolute positional relationship in the state in which the cathode ray tubes are arranged. [Industrial Applicability]
[0086] In the above embodiment, an example was shown in which the present invention is applied to an image forming apparatus as a color printer, but the present invention is not limited to this and can also be applied to image processing apparatuses such as copiers, facsimiles, MFPs, etc. Also, although a color printer has been described, a monochrome printer may also be used. [Explanation of symbols]
[0087] 11 image forming device, 12 image forming unit, 13 photosensitive drum, 14 charging roller, 15 exposure head, 16 developing device, 17 transfer roller, 18 transfer belt drive roller, 19 transfer belt driven roller, 20 transfer belt, 21 transfer unit, 22 recording paper, 24 hopping roller, 25 first conveying roller pair, 26 second conveying roller pair, 27 discharge roller pair, 28 discharge roller pair, 35 support plate, 36 biasing spring, 40 fixing device, 41 fixing belt unit, 42 pressure roller, 42a rotating shaft, 45 paper transport path, 46 paper stacker section, 100 frame, 101R right side plate, 101L left side plate, 103R right support lever, 103L left support lever 104 fixing belt, 105 heater unit, 105a flat portion, 107R right rotation fulcrum, 110R right rotation shaft hole, 111R right guide member, 111L left guide member, 112R right regulating portion, 113R inner guide portion, 114R right guide surface, 116R right guide hole, 121 cleaning roller, 122 refreshing roller, 123 opposing member, 123a attachment portion, 123b guide portion, 123c belt sliding surface, 123d belt introduction surface, 125 protrusion, 126R right roller shaft holder, 127R right compression spring, 130 spring receiving portion, 131 abutting flat portion, 150 nip portion, 160 electrical connector connection portion, 226R Right roller shaft holder, 228R right auxiliary holder portion, 229R right compression spring, 241 fixing belt unit, 326R first right shaft holder portion, 329R right compression spring, 330R second right shaft holder portion, 341 fixing belt unit, 351R first right bearing portion, 352 first guide, 353R second right bearing portion, 354 second guide, 500 virtual movement axis.
Claims
1. a rotating body extending in a first direction; a first cleaning member extending in the first direction and contacting the rotating body to clean it; a second cleaning member extending in the first direction and contacting and cleaning the first cleaning member; a biasing mechanism that biases the first cleaning member in a second direction toward the rotating body, a fixing device characterized in that, when a direction from the rotation shaft of the second cleaning member toward the rotation shaft of the first cleaning member is defined as a third direction, the third direction crosses the second direction from the downstream side to the upstream side in the rotation direction of the rotating body.
2. The diameter of the first cleaning member is 11 mm or more, and the angle θ of the third direction with respect to the second direction is 3°≦θ<90° 2. The fixing device according to claim 1, wherein:
3. The diameter of the first cleaning member is equal to or greater than 8 mm and less than 11 mm, and the angle θ of the third direction with respect to the second direction is 5°≦θ<90° 2. The fixing device according to claim 1, wherein:
4. the rotating body is a belt member, a facing member that faces the first cleaning member with the belt member interposed therebetween; 3. The fixing device according to claim 1, wherein the intermediate portion of the opposing member in the first direction has a protruding shape that protrudes downstream from a position where the rotating body contacts the first cleaning member.
5. The maximum protrusion amount t of the protrusion shape is 0[mm]<t≦1[mm] 5. The fixing device according to claim 4, wherein the setting is:
6. the first cleaning member and the second cleaning member are both roller members, The biasing mechanism includes: a first holding portion that holds a rotation shaft of the first cleaning member so that the rotation shaft can slide in the second direction; a second holding portion that holds a rotation shaft of the second cleaning member so that the rotation shaft of the second cleaning member is movable along the third direction relative to the first cleaning member that is in contact with the rotating body; a third biasing member that biases the second cleaning member in a direction in which the second cleaning member is pressed against the first cleaning member; 3. The fixing device according to claim 1, further comprising:
7. the first cleaning member and the second cleaning member are both roller members, The biasing mechanism includes: a shaft holder that is held so as to be movable in parallel in the second direction and that rotatably holds a rotation shaft of the first cleaning member and a rotation shaft of the second cleaning member; a first biasing member that biases the shaft holder in a direction toward the rotating body, the shaft holder holds a rotation shaft of the second cleaning member slidably along the third direction; 3. The fixing device according to claim 1, further comprising a second biasing member for biasing the second cleaning member in a direction in which the second cleaning member moves toward the first cleaning member.
8. the first cleaning member and the second cleaning member are both roller members, The biasing mechanism includes: a shaft holder that is held so as to be movable in parallel in the second direction and that rotatably holds a rotation shaft of the first cleaning member and a rotation shaft of the second cleaning member at a distance such that the first cleaning member and the second cleaning member come into contact with each other; a first biasing member that biases the shaft holder in a direction toward the rotating body; 3. The fixing device according to claim 1, further comprising:
9. 5. The fixing device according to claim 4, wherein the rotation axis of the second cleaning member is located downstream in the rotation direction of the rotating body with respect to a direction perpendicular to a tangent at a position where the first cleaning member and the opposing member contact each other.
10. 3. An image forming apparatus comprising the fixing device according to claim 1.
Citation Information
Patent Citations
JP1990051369U