Fixing device for image formation device and image formation device

Abstract

To provide a fixing device for an image formation device including a meandering detector with simple construction while preventing damage to an end part of a fixing belt.SOLUTION: A fixing device 10 includes: a fixing belt 11; a belt guide 33 rotatably holding the fixing belt 11; a main lamp 26 emitting light and provided within the fixing belt 11; a photosensor 37 detecting light and provided outside the fixing belt 11; and a control part 39 controlling a meandering of the fixing belt 11 according to a detection result by the photosensor 37.SELECTED DRAWING: Figure 3A

Description

[Technical Field]

[0001] The present disclosure relates to a fixing device of an image forming apparatus and an image forming apparatus. [Background technology]

[0002] In a conventional fixing belt meandering detection device for an image forming apparatus, when the fixing belt meanders to one side, the end of the fixing belt comes into contact with a meandering detection sensor to detect the meandering of the fixing belt. Such a fixing belt meandering detection device is disclosed, for example, in JP 2017-49513 A. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-49513 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional fixing belt meandering detection devices are configured as described above. However, with such fixing belt meandering detection devices, there is a possibility that the end of the fixing belt may be damaged due to contact between the end of the fixing belt and the fixing belt meandering detection sensor. On the other hand, there are also fixing belt meandering detection devices that use light-transmitting sensors, but these meandering detection devices require the installation of two sensors, a light-emitting sensor and a light-receiving sensor, which makes the configuration complicated.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a fixing device for an image forming apparatus and an image forming apparatus that has a meandering detection device with a simple configuration that does not cause damage to the end of the fixing belt. [Means for solving the problem]

[0006] The fixing device of the image forming apparatus according to the present disclosure includes a fixing belt, a belt guide that rotatably holds the fixing belt, a heat source that emits light and is provided within the fixing belt, a light detection unit that is provided outside the fixing belt and detects the light, and a meandering control means that controls the meandering of the fixing belt in accordance with the detection result of the light detection unit.

[0007] Preferably, a window is provided in the belt guide, a light detection unit is arranged opposite the window, the heat source is arranged inside the belt guide in the axial direction of the fixing belt, and when the light detection unit detects light, it determines whether the fixing belt is meandering, and the meandering control means controls the meandering of the fixing belt.

[0008] The meandering control means may be configured to be effective in controlling the meandering of the fixing belt only when the heat source is emitting light.

[0009] It is preferable that the belt guides are provided at both ends of the fixing belt in the axial direction, and when the fixing belt is positioned at the center in the axial direction, both of the windows of the belt guides are closed by the fixing belt.

[0010] The light detectors may be provided at both ends of the fixing belt in the axial direction, and when the light detectors at both ends detect light, it may be determined that the fixing belt is damaged.

[0011] The window of the belt guide is provided only on one side of the fixing belt, and a plurality of windows of the belt guide provided only on one side of the fixing belt may be provided.

[0012] In another aspect of the present invention, an image forming apparatus may include any one of the fixing devices described above. [Effects of the Invention]

[0013] According to the present disclosure, an optical detector located outside the fixing belt detects a heat source that emits light located inside the fixing belt, and controls the meandering of the fixing belt according to the detection results, thereby making it possible to control the meandering of the fixing belt without coming into contact with the fixing belt.

[0014] As a result, it is possible to provide a fixing device for an image forming apparatus and an image forming apparatus having a meandering detection device with a simple configuration, which does not cause damage to the end of the fixing belt.

[0015] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments, which proceeds with reference to the drawings. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view of an axial direction of a fixing device of an image forming apparatus according to an embodiment of the present disclosure. [Figure 2A] FIG. 4 is a perspective view showing a window of the belt guide. [Figure 2B] FIG. 10 is a front view of the window of the belt guide as viewed from the axial direction. [Figure 2C] FIG. 4 is a plan view of the window of the belt guide as viewed from the axial direction. [Figure 3A] 10 is a cross-sectional view showing the end of the fixing belt on the belt guide side where the window is provided when one photosensor is provided and the fixing belt is meandering toward the photosensor side. FIG. [Figure 3B] 10 is a cross-sectional view showing the end of the fixing belt on the belt guide side where the window is provided when the fixing belt is meandering toward the opposite side of the photosensor; FIG. [Figure 4] 10 is a flowchart showing the control performed by the control unit when there is one photosensor. [Figure 5] FIG. 10 is a diagram showing a state in which photosensors are arranged at both ends of the fixing belt in the axial direction. [Figure 6] 10 is a flowchart showing the control performed by the control unit when photosensors are disposed at both ends of the fixing belt in the axial direction. [Figure 7] FIG. 10 is a diagram showing a state in which a plurality of windows are provided in a belt guide according to a third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment of the present disclosure will be described in detail below with reference to the drawings. Fig. 1 is an axial cross-sectional view of a fixing device 10 of an image forming apparatus according to an embodiment of the present disclosure. Referring to Fig. 1, the fixing device 10 includes a fixing belt 11 having a circular cross section, a semicircular belt guide 33 that rotatably holds an upper portion of the fixing belt 11, and a pressure member 15 that is provided below the fixing belt 11 and forms a nip portion 13 (indicated by an arrow in the figure) that contacts the fixing belt 11 and applies pressure to a sheet 29. The fixing belt 11 is provided with a flat pad 17 for forming the nip 13, a support member 19 provided on the pad 17 and configured with an inverted-L-shaped member 20 and an L-shaped member 21 having a long side the same length as the long side of the inverted-L-shaped member 20, a reflector 23 provided to cover the long sides of the inverted-L-shaped member 20 and the L-shaped member 21 of the support member 19, and a heat source (halogen lamp) 25 including a main lamp 26 and a sub-lamp 27 arranged along the reflector 23. In the fixing device 10, a sheet of paper 29 is fed from the left side of the nip 13 and discharged to the right side, as indicated by the arrow in the figure. An inverted-L-shaped peeling plate 31 is provided on the discharge side of the nip 13 so as to abut against the fixing belt 11, making it easy to peel the sheet of paper 29 from the fixing belt 11.

[0018] A window (through hole) 35 is provided along the circumference of the belt guide 33 above the heat source 25. A photosensor (light detection unit) 37 is provided above the window 35 of the belt guide 33. In the drawing, the direction of light irradiation from the heat source 25 toward the photosensor 37 is indicated by an arrow.

[0019] Next, the belt guide 33 will be described. Fig. 2A is a perspective view showing the window 35 of the belt guide 33, Fig. 2B is a front view of the window 35 of the belt guide 33 as seen from the axial direction, and Fig. 2C is a plan view of the window 35 of the belt guide 33 as seen from the axial direction. With reference to Figs. 2A to 2C, the window 35 of the belt guide 33 has a rectangular shape that is long in the circumferential direction when viewed from above.

[0020] [First embodiment] First, we will explain the case where one photosensor 37 is provided. Fig. 3A is a cross-sectional view showing the end of fixing belt 11 on the belt guide 33 side where window 35 is provided when fixing belt 11 is meandering toward photosensor 37, and Fig. 3B is a cross-sectional view showing the end of fixing belt 11 on the belt guide 33 side where window 35 is provided when fixing belt 11 is meandering toward the opposite side of photosensor 37.

[0021] 3A and 3B, fixing belt 11 is rotatably held at both ends by semicircular belt guides 33 (note that in FIGS. 3A and 3B, the belt guide opposite photosensor 37 is not shown). A main lamp 26 (a sub-lamp is not shown) is provided inside fixing belt 11 in the axial direction as a heat source that emits light.

[0022] A window 35 is provided in one of the belt guides 33, and a photosensor 37 is provided outside the fixing belt 11 facing the window 35.

[0023] 3A and 3B show the positional relationship and specific example dimensions of the fixing belt 11, main lamp 26, belt guide 33 and its window 35, and photosensor 37. When the fixing belt 11 is not meandering, the fixing belt 11 is located between the positions shown in FIGS. 3A and 3B.

[0024] 3A and 3B also show a control unit (meandering control means) 39 that controls a meandering control device (not shown) that controls the meandering of the fixing belt 11 according to the detection result of the photosensor 37.

[0025] 3A and 3B, the belt guide 33 has a circumferential thickness of 2 mm and an axial length of 16 mm, and the window 35 is provided to have a width of 6.5 mm from a position 3 mm from the end of the belt guide 33. The axial length of the photosensor 37 is 6 mm, which is shorter than the length (6.5 mm) of the window 35, so that light from the main lamp 26 can sufficiently reach the photosensor 37 through the window 35.

[0026] 3A, when the fixing belt 11 is meandering toward the belt guide 33, the main lamp 26 is covered by the fixing belt 11 and the window 35 of the belt guide 33 is also covered by the fixing belt 11, so that light from the main lamp 26 does not reach the photosensor 37. On the other hand, as shown in FIG. 3B, when the fixing belt 11 is meandering away from the belt guide 33 to the right in the axial direction, the main lamp 26 protrudes from the fixing belt 11 and the window 35 of the belt guide 33 is no longer covered by the fixing belt 11, so that light from the main lamp 26 reaches the photosensor 37.

[0027] Next, a process of the control unit 39 that controls the meandering of the fixing belt 11 will be described. Fig. 4 is a flowchart showing the control contents performed by the control unit 39 when there is one photosensor 37. Referring to Fig. 4, the process starts when the power of the fixing device 10 is turned on (step S11; steps will be omitted below), and the warm-up of the fixing device 10 begins (S12). Next, it is determined whether the signal of the photosensor 37 is ON (S13).

[0028] If the signal from photosensor 37 is ON (ON in S13), it is determined that photosensor 37 has detected light, that fixing belt 11 is in the state shown in FIG. 3B, and that fixing belt 11 is meandering toward the opposite side of photosensor 37 (S14), and meandering adjustment is performed to move fixing belt 11 toward photosensor 37 (S15). When meandering adjustment is completed, the process returns to S13.

[0029] If the signal from photosensor 37 is OFF in S13 (OFF in S13), it is determined that photosensor 37 is not detecting light, fixing belt 11 is in the state shown in FIG. 3A, and fixing belt 11 is meandering toward photosensor 37 (S16), and meandering adjustment is performed to move fixing belt 11 to the opposite side of photosensor 37 (S17). When meandering adjustment is completed, the process returns to S13.

[0030] As described above, in the present disclosure, the meandering control of the fixing belt 11 by the control unit 39 is effective only when the heat source 25 such as the main lamp 26 is emitting light.

[0031] [Second embodiment] Next, a second embodiment will be described. In the second embodiment, photosensors are provided at both axial ends of the fixing belt 11. FIG. 5 is a diagram showing a state in which first and second photosensors 38a, 38b are arranged at both axial ends of the fixing belt 11. Here, the illustration of the belt guide 33 is omitted, but the belt guide (not shown) is arranged at both axial ends of the fixing belt 11 so that windows are located directly below the first and second photosensors 38a, 38b. Also shown here are the drive gear 30 for the fixing belt 11 and a control unit 40 that controls the meandering of the fixing belt 11 in the second embodiment.

[0032] That is, in this embodiment, a belt guide (not shown) holds both axial ends of the fixing belt 11, and light detection units are provided at both axial ends of the fixing belt 11, and when the fixing belt 11 is positioned in the axial center, all of the windows of the belt guide (not shown) are covered (blocked) by the fixing belt.

[0033] Next, the processing of the control unit 40 in the second embodiment will be described. Fig. 6 is a flowchart showing the control content performed by the control unit 40 when the first and second photosensors 38a, 38b are arranged at both axial ends of the fixing belt 11. Referring to Fig. 6, the processing starts when the power of the fixing device 10 is turned on (step S21), and the warm-up of the fixing device 10 begins (S22). Next, it is determined whether the signal of the first photosensor 38a on the left side of the fixing belt 11 is ON (S23).

[0034] If the signal from the first photosensor 38a is OFF in S23, it is determined whether the second photosensor 38b is ON or OFF. If the second photosensor 38b is ON (ON in S27), it is determined that the fixing belt 11 is meandering toward the first photosensor 38a (S28), and the meandering of the fixing belt 11 is adjusted so that it moves toward the second photosensor 38b (S29), and the process returns to S23.

[0035] If the second photosensor is OFF in S27 (OFF in S27), both the first photosensor and the second photosensor are OFF, so the current meandering state of the fixing belt 11 is maintained and the process returns to S23.

[0036] If the signal from the first photosensor 38a is ON in S23 (ON in S23), it is determined whether the signal from the second photosensor 38b is ON (S24). If the signal from the second photosensor 38b is ON (ON in S24), the two photosensors 38a and 38b are ON, and the dimension between both ends of the fixing belt 11 is different from the normal value. Therefore, it is detected that the fixing belt 11 is damaged (S25), and the fixing device 10 is stopped (S26).

[0037] In S24, if the signal of the second photosensor 38b is OFF (OFF in S24), it is determined that the fixing belt 11 is meandering toward the photosensor 38b side (S31), and a meandering adjustment is performed to move the fixing belt 11 toward the first photosensor 38a side (S32), and the process returns to S23.

[0038] As described above, according to the second embodiment, it is possible to determine whether the fixing belt 11 is meandering toward the first photosensor 38a, whether it is not meandering, or whether it is meandering toward the second photosensor 38b, and it is also possible to detect damage to the fixing belt 11.

[0039] [Third embodiment] Next, a third embodiment of the present disclosure will be described. Fig. 7 is a diagram showing a state in which a plurality of windows are provided in a belt guide at one end in the axial direction of fixing belt 11 in the third embodiment of the present disclosure. In the third embodiment, a photosensor is provided only at one end in the axial direction of fixing belt 11 to control meandering of fixing belt 11.

[0040] 7, in this embodiment, the belt guide 34 at one end of the axial direction of the fixing belt 11 is provided with three windows 36a, 36b, and 36c in the axial direction of the fixing belt 11, and a photosensor 38c is provided above the three windows 36a, 36b, and 36c so as to cover the three windows 36a, 36b, and 36c. The photosensor 38c detects which of the three windows 36a, 36b, and 36c receives the most light, thereby detecting whether the fixing belt 11 is meandering toward the belt guide 34, meandering toward the opposite side of the belt guide 34, or is in a normal position.

[0041] Here, the case where three windows are provided in the belt guide 34 has been described, but the present invention is not limited to this, and the number of windows may be four or more.

[0042] The meandering control device (not shown) that controls the meandering of the fixing belt 11 may perform meandering control in any manner. For example, when the control units 39 and 40 detect meandering of the fixing belt 11, they may control the meandering by tilting a roller (not shown) that guides the rotation of the fixing belt 11. In another method, when the control units 39 and 40 detect meandering of the fixing belt 11, they may shift the pressure member 15 by a predetermined angle from a direction perpendicular to the rotation axis (not shown) of the fixing belt 11, or may apply different pressure to the pressure member against both ends of the fixing belt 11. Naturally, a mechanism that directly controls the meandering of the fixing belt 11 by contacting the end of the fixing belt may also be provided.

[0043] The present disclosure can be implemented in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments are merely examples and should not be interpreted as being limited. All modifications and variations within the scope of the claims of the present disclosure are within the scope of the present disclosure. [Industrial Applicability]

[0044] According to the present disclosure, a fixing device for an image forming apparatus can be provided that does not cause damage to the end of the fixing belt and has a meandering detection device with a simple configuration, and is therefore useful as a fixing device for an image forming apparatus. [Explanation of symbols]

[0045] 10 Fixing device 11 Fixing belt 13 Nip section 15 Pressure member 17 Pads 19 Support member 20 Inverted L-shaped member 21 L-shaped member 23 Reflector 25 Heat source (halogen lamp) 26 Main Lamp 27 Sub Lamp 29 Paper 30 Drive gear 31 Peeling board 33,34 Belt guide 35, 36a, 36b, 36c Windows 37, 38a, 38b, 38c Photosensor (light detection unit) 39, 40 Control unit (meandering control means)

Claims

1. A fixing belt; a belt guide that rotatably holds the fixing belt; a heat source that is provided within the fixing belt and emits light; a light detection unit that is provided outside the fixing belt and detects light; a meandering control unit that controls the meandering of the fixing belt in accordance with the detection result of the light detection unit.

2. The belt guide is provided with a window, The light detection unit is disposed at a position facing the window, the heat source is disposed inside the belt guide in the axial direction of the fixing belt, determining whether the fixing belt is meandering when the light detection unit detects light; 2. The fixing device of the image forming apparatus according to claim 1, wherein the meandering control unit controls the meandering of the fixing belt.

3. 2. The fixing device of an image forming apparatus according to claim 1, wherein the meandering control means controls the meandering of the fixing belt only when the heat source is emitting light.

4. the belt guides are provided at both ends of the fixing belt in the axial direction, 3. The fixing device of an image forming apparatus according to claim 2, wherein when the fixing belt is positioned at the center in the axial direction, all of the windows of the belt guide are closed by the fixing belt.

5. the light detection units are provided at both ends of the fixing belt in the axial direction, 5. The fixing device of an image forming apparatus according to claim 4, wherein when the light detecting sections at both ends detect light, it is determined that the fixing belt is damaged.

6. 3. The fixing device of the image forming apparatus according to claim 2, wherein the window of the belt guide is provided only on one side of the fixing belt, and the number of windows of the belt guide provided only on one side of the fixing belt is plural.

7. An image forming apparatus comprising the fixing device according to any one of claims 1 to 6.

Images