Fixation device and image formation device

Abstract

To solve the problem of a fixation device that dirt formed on a separation member separating a recording medium from a heating member falls to cause a decrease in image quality.SOLUTION: A fixation device comprises: a fixation belt 104 which extends in a Y direction; a pressure roller 110 which extends in the same direction and is arranged to form a nip part while facing the fixation belt 104; contacting / leaving mechanisms (112, 107 and 108) which make the fixation belt 104 and pressure roller contact and leave each other; a separation separator 123 which is provided downstream from the nip part in the rotating direction of the fixation belt 104, and separates a recording sheet 37 from the fixation belt 104; and a separator cleaning member 133 which is juxtaposed for the separation separator 123, and cleans the separation separator 123 in association with providence operation of a providence mechanism.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, and more particularly to the configuration of a fixing device thereof. [Background technology]

[0002] Conventionally, a fixing device has been known in which a nip portion is formed between a first rotating body and a second rotating body, and a separation member for separating a medium from the first rotating body is provided downstream of the nip portion in the rotation direction of the first rotating body (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-161703 A (Page 7, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a problem in that dirt adhering to the separating member falls off, resulting in a deterioration in image quality. An object of the present invention is to provide a fixing device that can reduce the deterioration in image quality caused by dirt adhering to the separating member falling off. [Means for solving the problem]

[0005] The fixing device according to the present invention is characterized in having a first rotating body extending in a first direction, a second rotating body extending in the first direction and arranged to face the first rotating body and form a nip portion, a separation mechanism that brings the first rotating body and the second rotating body into contact with each other and separates them, a separation member that is provided downstream of the nip portion in the rotational direction of the first rotating body and separates a medium from the first rotating body, and a cleaning member that is provided alongside the separation member and cleans the separation member in conjunction with the separation and contact operation of the separation mechanism.

[0006] The image forming apparatus according to the present invention comprises the fixing device, a control unit that controls the entire apparatus, a printing unit equipped with the fixing device that performs printing based on instructions from the control unit, and a cleaning drive unit that drives the cleaning operation of the separating member by the cleaning member based on instructions from the control unit, and is characterized in that the control unit cleans the separating member of the fixing device after the printing operation by the printing unit is completed. Effect of the Invention

[0007] According to the present invention, it is possible to steadily remove dirt adhering to a separating member and allow the removed dirt to fall to a predetermined location. [Brief description of the drawings]

[0008] [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, which is provided with a fixing device. [Diagram 2] 1 is a diagram showing a configuration of a fixing device according to the present invention; [Diagram 3] 1A is a cross-sectional view of a main part showing a state in which the separation separator is in an operating position and the fixing belt is in a nipped state, and FIG. 1B is a cross-sectional view of a main part showing a state in which the separation separator is in a retracted position and the fixing belt is in a separated position in a separated state. [Figure 4] (a) shows the positional relationship between the fixing belt, pressure roller, separation separator unit, and separation separator cleaning unit in Figure 3(a), and (b) shows the positional relationship between the fixing belt, pressure roller, separation separator unit, and separation separator cleaning unit in Figure 3(b). [Diagram 5] 1A and 1B are operational explanatory diagrams for explaining the respective shapes and positional relationships between the tip of the separation separator and the tip of the separation separator cleaning member, where (a) shows the separation separator in an operative position, and (b) shows the separation separator in a retracted position. [Figure 6] 3 is a partially enlarged view showing only the separation separator unit and the separation separator cleaning unit shown in FIG. 2.

[0023] FIG. [Figure 7] 11 is an external perspective view showing the positional relationship of a separation protrusion, a cleaning protrusion, and a rib and a flat portion of a conveying guide disposed below them when the separation separator is in an operative position; FIG. [Figure 8] 5A and 5B are plan views showing the positional relationship of each tip portion, where FIG. 5A shows the separation separator in an operative position, and FIG. 5B shows the separation separator in a retracted position. [Figure 9] 4 is a block diagram illustrating a control system that controls the retraction operation of the separator and the release operation of the fixing belt. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Embodiment 1 FIG. 1 is a diagram showing the essential configuration of an image forming apparatus 11 according to a first embodiment of the present invention, which is equipped with a fixing device 25 according to the present invention.

[0010] Image forming device 11 has a configuration as, for example, an electrophotographic, direct transfer color printer, and four independent image forming units 12K, 12Y, 12M, and 12C (which may simply be referred to as image forming units 12 when there is no particular need to distinguish them) are detachably arranged in order from the upstream side along the transport direction (direction of arrow A) of recording paper 37 as a medium. Image forming unit 12K forms a black (K) image, image forming unit 12Y forms a yellow (Y) image, image forming unit 12M forms a magenta (M) image, and image forming unit 12C forms a cyan (C) image.

[0011] In this embodiment, the configurations of these image forming units 12K, 12Y, 12M, and 12C are identical, and only the color of the toner contained therein differs. Therefore, here, the internal structure of the black (K) image forming unit 12K will be described as an example.

[0012] The image forming unit 12K includes a photosensitive drum 13K (which may simply be referred to as photosensitive drum 13 when there is no particular need to distinguish between them), a charging roller 14K (which may simply be referred to as charging roller 14 when there is no particular need to distinguish between them) that uniformly charges the surface of the photosensitive drum 13K, a developing roller 16K (which may simply be referred to as developing roller 16 when there is no particular need to distinguish between them) that deposits black toner on the electrostatic latent image formed on the surface of the photosensitive drum 13K to form a toner image, and a supply roller 18K (which may simply be referred to as supply roller 18 when there is no particular need to distinguish between them) pressed against the developing roller 16K.

[0013] The supply roller 18K is a roller that supplies black toner contained in a toner container 20K (which may simply be referred to as a toner container 20 when there is no particular need to distinguish between them) to the corresponding developing roller 16K. A developing blade 19K (which may simply be referred to as a developing blade 19 when there is no particular need to distinguish between them) is pressed against the developing roller 16K. The developing blade 19K forms a thin layer of toner supplied from the supply roller 18K on the developing roller 16K.

[0014] Blade 24K (sometimes simply referred to as blade 24 when there is no need to distinguish between them) is placed in pressure contact with the surface of photoconductor drum 13K and scrapes off toner (residual toner) remaining on photoconductor drum 13K after transfer, which will be described later.

[0015] An exposure head 15K (sometimes simply referred to as exposure head 15 when no particular distinction is required) is disposed above the photoconductor drum 13K in a position facing the photoconductor drum 13K. Similarly, corresponding exposure heads 15Y, 15M, and 15C are disposed on the other photoconductor drums 13Y, 13M, and 13C, respectively. The exposure head 15 selectively exposes the photoconductor drum 13 to light in accordance with image data of the corresponding color, forming an electrostatic latent image on the surface.

[0016] A transfer unit 21 is disposed below each photoconductor drum 13 of the four image forming units 12. The transfer unit 21 includes transfer rollers 17K, 17Y, 17M, and 17C (which may be simply referred to as transfer rollers 17 when there is no need to distinguish them), and a transfer belt 23 that is arranged to be able to run in the direction of arrow A in FIG. 1 while being stretched by a transfer belt drive roller 21a and a transfer belt driven roller 21b.

[0017] Each transfer roller 17 is positioned in pressure contact with the corresponding photosensitive drum 13 via the transfer belt 23, and in the nip portion formed by the pressure contact, the recording paper 37 transported by the transfer belt 23 is charged to the 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 37 in a superimposed manner.

[0018] A paper feed mechanism for feeding recording paper 37 to the transfer belt 23 is disposed below the transfer unit 21 of the image forming device 11. The paper feed mechanism includes a paper feed tray 27 for storing the recording paper 37, a hopping roller 28 for removing the recording paper 37 from the paper feed tray 27, a paper guide section 33 for guiding the removed recording paper 37, and a pair of registration rollers 29 and 30 for transporting the guided recording paper 37 to the transfer belt 23.

[0019] A fixing device 25 is provided on the discharge side of the recording paper 37 from the transfer belt 23. The fixing device 25 has a fixing belt unit 102 and a pressure roller 110, and fixes the toner transferred onto the recording paper 37 by applying heat and pressure. On the discharge side of the fixing device 25, a pair of transport rollers 31, a paper guide section 34, a pair of discharge rollers 32 arranged at the rear end of the paper guide section 34, a paper stacker section 35, etc. are provided, and the printed recording paper 37 discharged from the fixing device 25 is discharged to the paper stacker section 35. The fixing device 25 will be described in detail later.

[0020] In addition, the X, Y, and Z directions in FIG. 1 are the X direction (arrow A direction) in which the recording paper 37 passes through the image forming units 12K, 12Y, 12M, and 12C, the Y direction is the direction of the rotation axis of the photoconductor drums 13K, 13Y, 13M, and 13C, and the Z direction is the direction perpendicular to both axes. In addition, when the X, Y, and Z directions are shown in other figures described later, these directions indicate common directions. That is, the XYZ 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. In addition, here, the Z direction is arranged to be approximately vertical.

[0021] 2 is a diagram showing the essential configuration of the fixing device 25 according to the present invention. When viewed from the direction of arrow A (FIG. 1), which is the conveying direction of the recording paper 37 by the transfer belt 23, the top (positive direction of the Z axis), bottom, left, right, front, and rear may be specified.

[0022] As shown in the figure, the fixing device 25 is arranged such that a pressure roller 110 as a second rotating body and a fixing belt unit 102 having a fixing belt 104 as an endless first rotating body located above the pressure roller 110 extend in the Y direction as a first direction, and a heater unit 105 is arranged inside the fixing belt 104 which also extends in the Y direction and heats the fixing belt 104 from the inside in the fixing belt unit 102. The Y direction in which the fixing belt unit 102 extends may be referred to as the longitudinal direction or the width direction of the recording paper 37.

[0023] The pressure roller 110 is rotatably supported at both ends of its rotation shaft 110a by a right side plate 101R and a left side plate 101L (not shown) arranged symmetrically therewith of the frame 100 of the fixing device 25, and is rotated in the direction of the arrow (counterclockwise) by receiving a rotational driving force from the outside. The frame 100 integrally includes the right side plate 101R and the left side plate 101L (not shown), and holds components of the fixing device 25, such as the pressure roller 110 and the fixing belt unit 102, in predetermined positions.

[0024] The heater unit 105 is disposed so that a flat portion of its lower part is in pressure contact with the elastic peripheral portion of the pressure roller 110 via the fixing belt 104, forming a nip portion 150. When the pressure roller 110 rotates in the direction of the arrow in this state, the fixing belt 104 also rotates therewith. At this time, the left and right ends of the fixing belt 104 are guided by left and right belt guide means as described later, and the fixing belt 104 rotates clockwise following the rotation of the pressure roller 110. Hereinafter, the movement of the fixing belt 104 rotating on its own axis while moving may be referred to as a rotational movement.

[0025] As described above, the recording paper 37 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 37 receives while passing through the nip portion 150, and the recording paper 37 is discharged from the fixing device 25.

[0026] Next, the configuration of the fixing belt unit 102 that rotatably supports the fixing belt 104 and disposes the heater unit 105 inside the fixing belt 104 will be further described.

[0027] 2, the right support lever 103R of the fixing belt unit 102 is rotatably held by the right side plate 101R at a right rotation fulcrum 107R, and supports the right end of the fixing belt 104 by a right belt guide means. Furthermore, the right support lever 103R also fixedly supports the right end of the heater unit 105 arranged inside the fixing belt 104. Therefore, the right support lever 103R, the right belt guide means, and the right end of the heater unit 105 are integrally configured.

[0028] The right support lever 103R, the right guide means, and the right end portion of the heater unit 105 are configured in the same manner as those at the left end portion of the fixing belt unit 102, including the right side plate 101R. That is, these are formed symmetrically with respect to an imaginary center plane that intersects perpendicularly at the center of the fixing belt unit 102 in the longitudinal direction (Y direction).

[0029] In addition, the reference numerals of the members arranged in plane symmetry at the left and right ends are suffixed with (L) and (R) to distinguish between left and right, for example, the left support lever 103L and the right support lever 103R, but when there is no particular need to distinguish between them, these suffixes may be omitted and the lever may be referred to as the support lever 103. In addition, for the components arranged in plane symmetry at the left and right ends of the fixing belt unit 102, only the configuration of the right end will be mainly described, and the left end will also be mentioned as necessary.

[0030] The fixing belt unit 102 configured as described above is rotatably supported on the main body of the fixing device 25 by a right rotation fulcrum 107R and a left rotation fulcrum 107L (not shown), as shown in FIG. 2, and is biased counterclockwise by a right rotation spring 108R suspended between the right side plate 101R and the right support lever 103R and a left rotation spring 108L (not shown) suspended between the left side plate 101L and the left support lever 103L (not shown).

[0031] As a result, the lower flat portion of heater unit 105 comes into pressure contact with the elastic peripheral portion of pressure roller 110 via fixing belt 104, forming nip portion 150. Note that the nipping amount of nip portion 150 at this time is determined here by the specifications of rotation spring 108, such as strength and length.

[0032] The fixing device 25 further includes a separation separator unit 121 and a separation separator cleaning unit 131. The separation separator unit 121 is disposed behind the fixing belt unit 102 (downstream of the fixing belt unit 102 in the paper transport direction). Note that Fig. 6 is a partially enlarged view showing only the separation separator unit 121 and the separation separator cleaning unit 131 shown in Fig. 2.

[0033] The recording paper 37 with the fixed toner image is discharged from the nip portion 150 in the direction of arrow B while passing through the nip portion 150, but may adhere to the fixing belt 104 which rotates clockwise, causing its leading edge to point upward. In this case, the separator unit 121 separates the recording paper 37 adhered to the fixing belt 104, and guides it to a conveying guide 113 fixedly disposed on the frame 100, and discharges it from the fixing device 25.

[0034] Therefore, the separation separator unit 121 is equipped with a separation separator 123 as a separation member that extends in the longitudinal direction (Y direction) along the peripheral surface of the fixing belt 104, has a Z-shaped cross section and is arranged so that its tip 123a (see Figure 6) is adjacent to the fixing belt 104, a right holding plate 122R that holds its right end, a left holding plate 122L (not shown) that holds its left end, a right support post 124R formed on the right holding plate 122R, and a left support post 124L (not shown) formed on the left holding plate 122L.

[0035] The separation separator unit 121, the separation separator cleaning unit 131, the right large diameter cam 112R, and the right small diameter cam 127R, which will be described later, are configured similarly at the left and right ends of the fixing device 25. That is, they are formed symmetrically with respect to an imaginary center plane that intersects perpendicularly at the center of the longitudinal direction (Y direction) of the fixing device 25, so the configuration of the right end of the fixing device 25 will be mainly described here, and the left end will also be mentioned as necessary.

[0036] In the separation separator unit 121, the right holding plate 122R supporting the right end of the separation separator 123 has a right support post 124R that penetrates and stands and is fitted into a right long guide hole 114R (see FIG. 3) formed in the right side plate 101R, so that the right holding plate 122R is held slidably in the extending direction of the long guide hole 114. Here, the rear side of the right long guide hole 114R is slightly inclined upward with respect to the horizontal direction. Furthermore, the right support post 124R is urged forward by a right compression spring 126R that is stretched between the right side plate 101R and the right support post 124R.

[0037] Meanwhile, a downwardly hanging L-shaped right guide abutment protrusion 125R (see FIG. 5) is disposed on the right end portion of the lower portion of the separation separator 123. This right guide abutment protrusion 125R abuts against an inclined abutment surface of a right flange 106R disposed on the right support lever 103R, and is involved in the movement of the separation separator unit 121 while being restricted by the right flange 106R which is displaced as the fixing belt unit 102 rotates about the rotation fulcrum 107, as described later.

[0038] The separation separator cleaning unit 131 is arranged opposite the separation separator 123 of the separation separator unit 121, and is equipped with a separator cleaning member 133 as a cleaning member whose tip end 133a (see Figure 6) is formed in an L-shape in cross section and intersects with the tip end 123a of the separation separator 123 as described below, a right holding plate 132R that holds the right end thereof, and a left holding plate 132L (not shown) that holds the left end thereof.

[0039] The right holding plate 132R is formed with an elongated hole 134R into which a regulating post erected from the right side plate 101R is fitted, and is fixed to the frame 100 after its position has been adjusted in the front-rear direction by a fixing member (not shown).

[0040] The right large diameter cam 112R rotates around the right cam shaft 116R upon receiving an external driving force, thereby rotating the fixing belt unit 102 around the right rotation fulcrum 107R, as described below, and the right small diameter cam 127R rotates around the right cam shaft 129R upon receiving an external driving force, thereby displacing the separation separator unit 121 against the force of the right compression spring 126R, as described below.

[0041] In the above configuration, a retraction operation for retracting the separation separator 123 from an operating position (state in FIG. 2) close to the fixing belt 104 to a retracted position will be described. This retraction operation is performed in conjunction with a release operation for the fixing belt 104 from a nip state (state in FIG. 2) with the pressure roller 110 to a separated state. In addition, since the separation separator unit 121, the separation separator cleaning unit 131, the right large diameter cam 112R, and the right small diameter cam 127R are formed similarly at the left and right ends of the fixing device 25, the operation of the right end of the fixing device 25 will be mainly described here.

[0042] 3A is a cross-sectional view of the main part showing the separation separator 123 in the operating position and the nip state of the fixing belt 104, and FIG. 3B is a cross-sectional view of the main part showing the separation separator 123 in the retracted position and the fixing belt 104 in the separated position. For ease of explanation, the right holding plate 122R and the right holding plate 132R are omitted in FIG.

[0043] Figure 4 is an operational explanatory diagram for explaining the retraction and release operations, where Figure 4(a) shows the positional relationship between the fixing belt 104, pressure roller 110, separation separator unit 121, and separation separator cleaning unit 131 in Figure 3(a), and Figure 4(b) shows the positional relationship between the fixing belt 104, pressure roller 110, separation separator unit 121, and separation separator cleaning unit 131 in Figure 3(b).

[0044] As shown in Fig. 3(a), when the fixing belt 104 is in a nipped state and the separation separator 123 is in the operating position, the right large diameter cam 112R rotates in the direction of the arrow (clockwise) to separate the fixing belt 104 from the pressure roller 110. As a result, the right large diameter cam 112R presses the right contact flat surface portion 109R of the right support lever 103R, and rotates the fixing belt unit 102 in the direction of the arrow (clockwise) around the rotation fulcrum 107 against the bias of the right rotation spring 108R, and eventually, as shown in Fig. 3(b), the fixing belt 104 moves to the separated position. The large diameter cam 112, the rotation spring 108, the rotation fulcrum 107, etc. correspond to a contact / separation mechanism.

[0045] Meanwhile, accompanying this release operation, the right small diameter cam 127R also rotates in the direction of the arrow (clockwise) in synchronization with the rotation of the right large diameter cam 112R. As a result, as shown in Fig. 4, the right cutout portion 128R of the right small diameter cam 127R acts on and presses the right support post 124R guided by the right guide long hole 114R, and eventually, as shown in Fig. 4(b), the separation separator 123 is retracted to the retracted position against the bias of the right compression spring 126R.

[0046] 3, the right guide abutment protrusion 125R hanging down from the bottom of the separation separator 123 is pushed backward from the position shown in FIG. 3(a) to the position shown in FIG. 3(b) by the inclined portion of the right flange 106R which abuts against it and which is displaced with the rotation of the fixing belt unit 102. As a result, the separation separator 123 moves in parallel from the operating position shown in FIG. 3(a) to the retracted position shown in FIG. 3(b) while maintaining substantially the same posture.

[0047] FIG. 5 is an operational explanatory diagram illustrating the shape and positional relationship between the tip 123a of the separation separator 123 and the tip 133a of the separator cleaning member 133, where FIG. 5(a) shows the separation separator 123 in the operative position and FIG. 5(b) shows the separation separator 123 in the retracted position.

[0048] As shown in Fig. 5, a separation protrusion 123b as a tapered convex portion is formed in a comb-tooth shape along the longitudinal direction (Y direction) at a tip 123a of the separation separator 123, and a cleaning protrusion 133b similarly formed in a tapered shape is formed in a comb-tooth shape along the longitudinal direction (Y direction) at a tip 133a of the separator cleaning member 133. Note that Fig. 6 corresponds to a cross-sectional view in the XZ plane including the tip of the separation protrusion 123b shown in Fig. 5(a).

[0049] 5(a) and 6, when the separation separator 123 is in the operating position, the separation protrusions 123b and the cleaning protrusions 133b cross each other. Therefore, when the separation separator 123 is in the operating position, the tip 123a of the separation separator 123 is disposed so as to obtain a cross angle θ with respect to the tip 133a of the separator cleaning member 133, and the separation protrusions 123b and the cleaning protrusions 133b are formed so as to be alternately shifted in the longitudinal direction (Y direction).

[0050] Figure 7 is an external oblique view showing the relative positions of the separation protrusion 123b, the cleaning protrusion 133b, the rib 113a of the conveying guide 113 (see Figure 2) located below them, and the flat portion 113b serving as a storage portion when the separation separator 123 is in the operative position, and Figure 8 is a plan view showing the positional relationship of each of these tip portions, with Figure 7(a) showing the separation separator 123 when it is in the operative position and Figure 8(b) showing the separation separator 123 when it is in the retracted position.

[0051] 7, a plurality of ribs 113a are formed on the conveying guide 113 at equal intervals along the longitudinal direction so as to extend in the paper conveying direction. Therefore, the recording paper 37 separated from the fixing belt 104 by the separating separator 123 is guided and conveyed by the ridges of the ribs 113a, and is discharged to the outside of the fixing device 25 without coming into contact with the flat portions 113b between the ribs 113a.

[0052] On the other hand, as shown in Fig. 8, the position of the tip of the cleaning protrusion 133b and the position of the tip of the ridge of the rib 113a of the conveying guide 113 on the upstream side of the paper conveying direction are approximately the same, and as shown in Fig. 8(a), the position of the tip of the separation protrusion 123b when the separation separator 123 is in the operating position is located upstream of these. Also, in the vertical direction (Z direction), the rib 113a is located below the cleaning protrusion 133b. Therefore, the upper ridge 133c of the recess of the tip 133a of the separator cleaning member 133 formed in a comb-tooth shape described later is located above the flat part 113b of the conveying guide 113.

[0053] In the above configuration, the movement of the separator unit 121 will be further described.

[0054] As described above, when the release operation of the fixing belt 104 and the retraction operation of the separation separator 123 are performed, the fixing belt 104 separates from the nip state with the pressure roller 110 shown in FIG. 3(a) and moves to the separated position shown in FIG. 3(b), and the separation separator 123 moves approximately parallel from the operating position shown in FIG. 4(a) to the retracted position shown in FIG. 4(b).

[0055] 5(a) and 6, each separation protrusion 123b of the separation separator 123, which is in a state of intersecting with the cleaning protrusion 133b of the separator cleaning member 133 in the operating position, moves in parallel to the rear retracted position while maintaining the intersection angle θ shown in Fig. 6. As a result, the lower surface of each separation protrusion 123b moves in parallel while sliding against the upper ridge 133c (Fig. 5(b)) of the recess in the tip 133a of the separator cleaning member 133, which is formed in a comb-tooth shape.

[0056] Therefore, dirt that occurs on the tip and underside of each separation protrusion 123b of the separation separator 123 due to friction or the like that occurs when separating the recording paper 37 adhering to the fixing belt 104 is removed from the tip to the entire underside by the parallel movement of the separation separator 123 backward.

[0057] This prevents the separation protrusions 123b from becoming dirty on the recording paper 37 that is separated from the fixing belt 104 by the separation protrusions 123b and conveyed while being guided along the lower surface of each separation protrusion 123b.

[0058] In addition, since the separation protrusion 123b of the separation separator 123 is tapered, the width area where dirt occurs becomes narrower as it approaches the tip, and the sliding area with the upper edge 133c of the separator cleaning member 133 also becomes narrower, making it easier to remove dirt accumulated due to adhered toner and paper powder. Also, the closer to the tip, the more limited the position where dirt falls and accumulates.

[0059] 8(b), the upper ridge 133c of the separator cleaning member 133, which removes dirt from the separation protrusions 123b of the separation separator 123, is located above the flat portion 113b between the ribs 113a of the conveying guide 113 in the width direction (Y direction), so that the scraped-off dirt falls onto the flat portion 113b of the conveying guide 113. Therefore, the accumulated dirt does not adhere to the recording paper 37 being conveyed.

[0060] 8B, the rear end position 110b of the pressure roller 110 located vertically below is indicated by a dashed line. In this manner, the upper edge portion 133c of the separator cleaning member 133 that scrapes off dirt from the separation separator 123 is located behind not only the fixing belt 104 but also the pressure roller 110 in the horizontal direction (X direction).

[0061] In this embodiment, the dirt scraped off from the separation separator 123 falls onto the flat portion 113b of the conveying guide 113 and is configured so as not to come into contact with the fixing belt 104 or the pressure roller 110. However, by positioning the upper ridge portion 133c as described above, the scraped off dirt is basically configured to be less likely to fall onto the pressure roller 110 located below.

[0062] FIG. 9 is a block diagram that illustrates a control system that controls the retreat operation of separator 123 and the release operation of fixing belt 104. As shown in FIG.

[0063] In the figure, a control unit 201 controls the operation of the entire image forming apparatus 11, a printing unit 202 includes a fixing device 25 and executes a printing operation according to instructions from the control unit 201, and a cam control unit 203 controls the rotation of a large diameter cam motor 205 that rotates and drives the cam shaft 116 of the large diameter cam 112 and a small diameter cam motor 206 that rotates and drives the cam shaft 129 of the small diameter cam 127 of the fixing device 25 according to instructions from the control unit 201. The cam control unit 203, the large diameter cam motor 205, and the small diameter cam motor 206 correspond to a cleaning drive unit.

[0064] In the above configuration, the control unit 201 issues an instruction to the cam control unit 203 to change the fixing belt 104 from the separated state to the nipped state by the rotation of the large diameter cam motor 205 and the small diameter cam motor 206 and to move the separation separator 123 from the retracted position to the operating position in synchronization with issuing a print instruction to the printing unit 202 to execute printing. Then, the control unit 201 issues an instruction to the cam control unit 203 to change the fixing belt 104 from the nipped state to the separated state by the rotation of the large diameter cam motor 205 and the small diameter cam motor 206 in synchronization with issuing a print stop instruction to the printing unit 202 to stop printing.

[0065] In this embodiment, the large diameter cam 112 and the small diameter cam 127 are configured to rotate synchronously by receiving driving forces separately from outside the fixing device 25, but the present invention is not limited to this configuration. For example, a gear train that receives the rotation of the large diameter cam 112 and transmits the rotation to the small diameter cam 127 may be provided inside the fixing device 25, and these may be configured to rotate in the same direction at an appropriate rotation ratio (for example, 1:1). Various other configurations are possible.

[0066] As described above, according to the fixing device 25 of the present embodiment, dirt adhering to the separation separator 123 when the recording paper 37 is separated from the fixing belt 104 is removed, and the removed dirt is dropped and stored on the flat portion 113b of the conveying guide 113 with which the conveyed recording paper 37 does not come into contact, thereby preventing the conveyed recording paper 37 from becoming dirty.

[0067] In addition, since the removed dirt can be prevented from falling onto the pressure roller 110 disposed below, a cleaning mechanism for the pressure roller 110 is not required, and therefore an increase in the load and an increase in costs can be prevented.

[0068] In addition, in the description of the above embodiment, words such as "upper," "lower," "left," "right," "front," and "rear" are used, but these are used for convenience and do not limit the absolute positional relationship in the state in which the image forming device or fixing device is arranged. [Industrial Applicability]

[0069] 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 used in 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]

[0070] 11 image forming device, 12 image forming unit, 13 photosensitive drum, 14 charging roller, 15 exposure head, 16 developing roller, 17 transfer roller, 18 supply roller, 19 developing blade, 20 toner storage section, 21 transfer unit, 21a transfer belt drive roller, 21b transfer belt driven roller, 23 transfer belt, 24 blade, 25 fixing device, 27 paper feed tray, 28 hopping roller, 29 registration roller pair, 30 registration roller pair, 31 transport roller pair, 32 discharge roller pair, 33 paper guide section, 34 paper guide section, 35 paper stacker section, 37 recording paper, 100 frame, 102 fixing belt unit, 103 support lever, 104 fixing belt, 105 heater unit, 106 flange, 107 pivot point, 108 pivot spring, 109 flat contact surface, 110 pressure roller, 110a rotation shaft, 110b rear end position, 112 large diameter cam, 113 conveying guide, 113a rib, 113b flat portion, 114 long guide hole, 116 cam shaft, 121 separation separator unit, 122 holding plate, 123 separation separator, 123a tip portion, 123b separation projection portion, 124 support post, 125 guide contact projection, 126 compression spring, 127 small diameter cam, 128 notch portion, 129 cam shaft, 131 separation separator cleaning unit, 132 holding plate, 133 separator cleaning member, 133a Tip portion, 133b cleaning protrusion portion, 133c upper ridge portion, 134 long hole, 150 nip portion, 201 control portion, 202 printing portion, 203 cam control portion, 205 large diameter cam motor, 206 small diameter cam motor.

Claims

1. A first rotor extending in a first direction; a second rotating body extending in the first direction and disposed to face the first rotating body and form a nip portion; a contact / disconnect mechanism that brings the first rotating body and the second rotating body into contact with each other and separates them from each other; a separating member provided downstream of the nip portion in a rotation direction of the first rotating body and configured to separate a medium from the first rotating body; a cleaning member provided alongside the separating member and configured to clean the separating member in association with the contacting and separating operation of the contact / separation mechanism; A fixing device comprising:

2. the separating member is a separator extending in a width direction of the medium and provided opposite to the first rotating body, The separator is 2. The fixing device according to claim 1, wherein the cleaning member moves in a direction away from the first rotating body and is cleaned by contact with the cleaning member when the first rotating body and the second rotating body are separated from each other by the separation mechanism.

3. The separator is 3. The fixing device according to claim 2, wherein, during the separation operation, the cleaning member moves in a horizontal direction away from the first rotating body and comes into contact with and is cleaned by the cleaning member in an area that does not overlap with the first rotating body and the second rotating body in a vertical direction.

4. 4. The fixing device according to claim 3, wherein a first end portion of the separator facing the first rotating body has a first comb-tooth shape, and the cleaning member has a second end portion having a second comb-tooth shape capable of intersecting with the first end portion.

5. 5. The fixing device according to claim 4, wherein the cleaning member performs cleaning by sliding the recesses of the second comb-tooth shape over the protrusions of the first comb-tooth shape of the separator.

6. The fixing device according to claim 5, characterized in that a plurality of ribs for guiding the medium are formed in an area not including a vertically downward area of ​​the portion where the second comb-tooth-shaped recess slides against the first comb-tooth-shaped protrusion of the separator, and a storage section is provided between the plurality of ribs for storing dirt scraped off the separator.

7. A fixing device according to claim 1 or 2; A control unit that controls the entire device; a printing unit including the fixing device that executes printing based on an instruction from the control unit; a cleaning drive unit that drives the cleaning operation of the separating member by the cleaning member based on an instruction from the control unit; Equipped with The image forming apparatus according to claim 1, wherein the control unit cleans the separating member of the fixing device after the printing operation by the printing unit is completed.

Images