Blower device and image forming apparatus

Abstract

To achieve a change of an air blowing range of a rotating body in a rotation axis direction or a longitudinal direction with a simple configuration.SOLUTION: An air blowing device 30 blows air to a rotating body 22 included in a heating device 20 heating a recording medium on which an image is formed, and comprises: an airflow generating member 31 that generates an airflow sent to an outer peripheral surface of the rotating body 22; and an air blowing range changing mechanism 33 that changes a range on the outer peripheral surface of the rotating body 22 to which air is sent in a longitudinal direction X of the rotating body 22. The air blowing range changing mechanism 33 includes a first partition member 34 that faces the outer peripheral surface of the rotating body 22 and is movable in a direction to approach and separate from the outer peripheral surface of the rotating body 22, and a second partition member 35 that faces the outer peripheral surface of the rotating body 22 and is movable in the longitudinal direction X of the rotating body 22.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a blower device and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art As an example of a heating device installed in an image forming apparatus such as a copier or a printer, a fixing device is known that heats paper while sandwiching the paper between a pair of rotating bodies such as an endless belt or rollers, thereby fixing an image on the paper.

[0003] In a fixing device, since the heat of the non-paper passing area where the paper does not pass tends not to be taken away by the paper, when multiple sheets of paper are passed continuously, the heat of the rotor in the non-paper passing area gradually accumulates, and the temperature rise becomes significant. To address this problem, in conventional fixing devices, a fan or the like is used to blow air to the non-paper passing area of ​​the rotor to suppress the temperature rise in the non-paper passing area.

[0004] In addition, the range of temperature rise in the non-paper passing area as described above differs depending on the size of the paper being passed. For this reason, the following Patent Document 1 (JP Patent Publication 2006-119259 A) proposes a configuration in which a pair of plate-like bodies provided in a duct are opened and closed to change the air path of the cooling air to the longitudinal direction of the fixing roller depending on the size of the paper. Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of the configuration proposed in the above Patent Document 1, in order to open and close the pair of plate-like bodies, it is necessary to provide a drive mechanism consisting of a nut, a shaft, etc., as well as guides to guide each plate-like body, which results in a problem that the configuration becomes complicated and it is difficult to simplify the configuration. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an air blowing device that blows air onto a rotating body included in a heating device that heats a recording medium on which an image has been formed, the air blowing device including an airflow generating member that generates an airflow to be blown onto an outer circumferential surface of the rotating body, and an airflow range changing mechanism that changes the range of the airflow to be blown onto the outer circumferential surface of the rotating body in the direction of the rotation axis or the longitudinal direction of the rotating body, the airflow range changing mechanism being opposed to the outer circumferential surface of the rotating body and The rotor moves in a direction different from the direction of the rotation axis of the rotor or in a direction different from the longitudinal direction of the rotor. and a second partition member that faces the outer peripheral surface of the rotor and is movable in the direction of the rotation axis or in the longitudinal direction of the rotor. Effect of the Invention

[0007] According to the present invention, the air blowing range can be changed in the rotational axis direction or longitudinal direction of the rotating body with a simple configuration. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic configuration diagram of a fixing device according to the present embodiment. [Diagram 3] 3A and 3B are diagrams illustrating a paper passing area and a paper non-passing area in the fixing device. [Figure 4] 1 is a diagram showing a configuration of a blower device according to an embodiment of the present invention; [Diagram 5] 13 is a diagram showing a state in which the first partition member is separated from the pressure roller. FIG. [Figure 6] 13 is a diagram showing a state in which the second partition member has moved to the center side in the longitudinal direction of the pressure roller. FIG. [Figure 7] 13 is a diagram showing a moving mechanism for a second partition member. FIG. [Figure 8] FIG. 11 is a timing chart showing a change in the air volume of a fan. [Figure 9] 13A and 13B are diagrams showing other examples in which the orientation and arrangement of the fans are different. [Figure 10] 13A and 13B are diagrams showing yet another example in which the orientation and arrangement of fans are different. [Figure 11]FIG. 13 is a diagram showing an example in which a blower is disposed on the fixing roller side. [Figure 12] FIG. 13 is a diagram showing an example in which air blowers are arranged on both the fixing roller side and the pressure roller side. [Figure 13] FIG. 1 is a diagram illustrating an example of an image forming apparatus using an end-based transport system. [Figure 14] FIG. 1 is a diagram showing an example in which the present invention is applied to an image forming apparatus using an end-based transport system. [Figure 15] 11A and 11B are diagrams illustrating examples of other fixing devices to which the present invention can be applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described below with reference to the accompanying drawings. In each drawing for explaining the present invention, components such as members and components having the same function or shape are given the same reference numerals as far as they can be distinguished, and the description thereof will be omitted after the first description.

[0010] FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. In this specification, the term "image forming apparatus" includes a printer, a copier, a facsimile, a printing machine, or a multifunction machine that combines two or more of these. In addition, the term "image formation" used in the following description means not only forming an image having meaning such as a character or a figure, but also forming an image having no meaning such as a pattern. First, the overall configuration and operation of the image forming apparatus according to this embodiment will be described with reference to FIG. 1.

[0011] As shown in FIG. 1, the image forming apparatus 100 according to this embodiment includes an image forming unit 200 that forms an image on a sheet-like recording medium such as paper, a fixing unit 300 that fixes the image on the recording medium, a recording medium supply unit 400 that supplies the recording medium to the image forming unit 200, and a recording medium discharge unit 500 that discharges the recording medium outside the apparatus.

[0012] The image forming section 200 is provided with four process units 1Y, 1M, 1C, and 1Bk as image creating units, an exposure device 6 that forms an electrostatic latent image on the photosensitive member 2 provided in each of the process units 1Y, 1M, 1C, and 1Bk, and a transfer device 8 that transfers the image onto a recording medium.

[0013] Each process unit 1Y, 1M, 1C, and 1Bk has basically the same configuration, except that it contains toner (developer) of a different color, yellow, magenta, cyan, or black, which corresponds to the color separation components of a color image. Specifically, each process unit 1Y, 1M, 1C, and 1Bk includes a photoconductor 2 as an image carrier that carries an image on its surface, a charging member 3 that charges the surface of the photoconductor 2, a developing device 4 that supplies toner as a developer to the surface of the photoconductor 2 to form a toner image, and a cleaning member 5 that cleans the surface of the photoconductor 2.

[0014] The transfer device 8 includes an intermediate transfer belt 11, a primary transfer roller 12, and a secondary transfer roller 13. The intermediate transfer belt 11 is an endless belt member, and is stretched by a plurality of support rollers. Four primary transfer rollers 12 are provided inside the intermediate transfer belt 11. Each primary transfer roller 12 contacts each photoconductor 2 via the intermediate transfer belt 11, thereby forming a primary transfer nip between the intermediate transfer belt 11 and each photoconductor 2. The secondary transfer roller 13 contacts the outer peripheral surface of the intermediate transfer belt 11, forming a secondary transfer nip.

[0015] Fixing section 300 is provided with fixing device 20. Fixing device 20 includes fixing roller 21 as a fixing member, pressure roller 22 as a pressure member, etc. Fixing roller 21 and pressure roller 22 are in pressure contact with each other, and a nip portion (fixing nip) is formed between these rollers 21, 22.

[0016] The recording medium supply unit 400 is provided with a paper feed cassette 14 that stores paper P as a recording medium, and a paper feed roller 15 that feeds paper P from the paper feed cassette 14. In the following description, the "recording medium" will be described as "paper", but the "recording medium" is not limited to paper (paper). The "recording medium" includes not only paper (paper) but also overhead projector sheets or fabrics, metal sheets, plastic films, or prepreg sheets in which carbon fibers are pre-impregnated with resin. In addition to plain paper, "paper" also includes cardboard, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and the like.

[0017] The recording medium ejection section 500 is provided with a pair of ejection rollers 17 for ejecting the paper P outside the image forming apparatus, and an ejection tray 18 on which the paper P ejected by the ejection rollers 17 is placed.

[0018] Next, the printing operation of the image forming apparatus 100 according to this embodiment will be described with reference to FIG.

[0019] When a printing operation is started in the image forming apparatus 100, the photoconductors 2 of the process units 1Y, 1M, 1C, and 1Bk and the intermediate transfer belt 11 of the transfer device 8 start to rotate. Also, the paper feed roller 15 starts to rotate, and the paper P is fed out from the paper feed cassette 14. The fed paper P comes into contact with a pair of timing rollers 16 and stops, and the transport of the paper P is temporarily stopped until an image to be transferred onto the paper P is formed.

[0020] In each process unit 1Y, 1M, 1C, 1Bk, first, the surface of the photoconductor 2 is charged to a uniform high potential by the charging member 3. Next, the exposure device 6 exposes the surface (charged surface) of each photoconductor 2 based on the image information of the document read by the document reading device or the print image information instructed to be printed from the terminal. As a result, the potential of the exposed portion is reduced and an electrostatic latent image is formed on the surface of each photoconductor 2. Then, the developing device 4 supplies toner to this electrostatic latent image, and a toner image is formed on each photoconductor 2. When the toner image formed on each photoconductor 2 reaches the primary transfer nip (the position of the primary transfer roller 12) as each photoconductor 2 rotates, it is transferred to the rotating intermediate transfer belt 11 so as to be overlapped in sequence. In this way, a full-color toner image is formed on the intermediate transfer belt 11. The image forming apparatus 100 can form a monochrome image using any one of the process units 1Y, 1M, 1C, and 1Bk, or can form a two-color or three-color image using any two or three of the process units. After the toner image is transferred from the photoconductor 2 to the intermediate transfer belt 11, the cleaning member 5 removes residual toner and the like from each photoconductor 2.

[0021] The toner image transferred onto the intermediate transfer belt 11 is transported to the secondary transfer nip (the position of the secondary transfer roller 13) as the intermediate transfer belt 11 rotates, and is transferred onto the paper P that has been transported thereto by the timing roller 16. The paper P is then transported to the fixing device 20, and the toner image on the paper P is heated and pressurized by the fixing roller 21 and the pressure roller 22, thereby fixing the toner image to the paper P. The paper P is then transported to the recording medium discharge section 500, and is discharged onto the paper discharge tray 18 by the paper discharge roller 17. This completes the series of printing operations.

[0022] Next, the configuration of the fixing device 20 according to the present embodiment will be described with reference to FIG.

[0023] As shown in FIG. 2, the fixing device 20 includes, in addition to the fixing roller 21 and the pressure roller 22, a halogen heater 23 as a heat source and a temperature sensor 24 as a temperature detection member.

[0024] The fixing roller 21 is a rotating body (first rotating body) that functions as a fixing member that fixes the unfixed toner T to the paper P. The fixing roller 21 has an aluminum base having an outer diameter of 30 mm and a thickness of 0.7 mm, for example. The material of the base may be other metal materials such as iron, in addition to aluminum. On the outer circumferential surface of the base, a release layer having a thickness of, for example, 5 to 50 μm and made of a fluorine-based resin such as PFA or PTFE is provided in order to ensure durability and releasability. In addition, an elastic layer made of rubber or the like may be provided between the base and the release layer.

[0025] The pressure roller 22 is a rotating body (second rotating body) disposed opposite the fixing roller 21. The pressure roller 22 is also a pressing member that is pressed against the fixing roller 21 to form a nip portion N. The pressure roller 22 is pressed against the outer circumferential surface of the fixing roller 21 by a biasing member such as a spring. As a result, the nip portion N is formed between the fixing roller 21 and the pressure roller 22 (at the contact point). The pressure roller 22 has an outer diameter of, for example, 30 mm, and includes a solid iron core, an elastic layer provided on the outer circumferential surface of the core, and a release layer provided on the outer circumferential surface of the elastic layer. The elastic layer has a thickness of, for example, 10 mm, and is made of silicone rubber or the like. The release layer has a thickness of, for example, about 30 μm, and is made of a fluorine-based resin such as PFA or PTFE.

[0026] A halogen heater 23 is disposed inside the fixing roller 21. The halogen heater 23 generates heat, thereby heating the fixing roller 21 from the inside. In addition to the halogen heater 23, a carbon heater, a ceramic heater, or an IH (electromagnetic induction heating) type heating source can also be used as a heat source for heating the fixing roller 21.

[0027] The output (heat generation amount) of the halogen heater 23 is controlled based on the surface temperature of the fixing roller 21 detected by the temperature sensor 24. When the temperature sensor 24 is a non-contact type sensor arranged in a non-contact manner with the fixing roller 21, the temperature sensor 24 detects the atmospheric temperature in the vicinity of the fixing roller 21 as the temperature of the fixing roller 21. The temperature sensor 24 may also be a contact type sensor that contacts the outer peripheral surface of the fixing roller 21. As the temperature sensor 24, a known temperature sensor such as a thermopile, a thermostat, a thermistor, or an NC sensor can be used.

[0028] The temperature of the fixing roller 21 is maintained at a predetermined temperature by controlling the output of the halogen heater 23 based on the temperature detected by the temperature sensor 24. In this state, when a sheet of paper P carrying unfixed toner T enters between the fixing roller 21 and the pressure roller 22 (nip portion N) as shown in Fig. 2, the unfixed toner T is pressurized and heated by the fixing roller 21 and the pressure roller 22, and the toner image is fixed to the sheet of paper P.

[0029] 3, the fixing device 20 according to this embodiment is configured to be capable of passing papers P1 to P4 of various width sizes. The halogen heater 23 is disposed over the entire maximum paper passing area (maximum recording medium passing area) A, which is an area through which the paper P4 of the maximum width W4 passes, so that any paper can be heated.

[0030] However, if the halogen heater 23 is disposed over the entire maximum paper passing area A, when various papers P1-P3 having a width smaller than the maximum width paper P4 are passed through, heat is not consumed as much in the non-paper passing areas (recording medium non-passing areas) B1-B3 where these papers P1-P3 do not pass through, and heat is instead accumulated. Therefore, the temperature is more likely to rise in the non-paper passing areas B1-B3 than in the paper passing areas. In particular, when a plurality of various papers P1-P3 having a small width are passed through in succession, the temperature rise in each of the non-paper passing areas B1-B3 becomes significant, and there is a risk that the temperature of the fixing roller 21 or the pressure roller 22 will exceed its heat-resistant temperature.

[0031] The problem of temperature rise in the non-paper passing area can be improved by using a blower such as a fan to blow air into the non-paper passing area. However, the range of temperature rise in the non-paper passing area varies depending on the size of the paper being passed. Therefore, in order to effectively suppress the temperature rise in the non-paper passing area, it is necessary to change the air blowing range depending on the paper size. Therefore, in this embodiment, the following configuration is adopted to make it possible to change the air blowing range.

[0032] The configuration of the blower according to this embodiment will be described below with reference to Figs.

[0033] As shown in Figure 4, the blower device 30 of this embodiment includes a fan 31 as an airflow generating member that generates an airflow, a duct 32 as a flow path forming member that forms a flow path for guiding the airflow generated by the fan 31 to the pressure roller 22, and an air blowing range changing mechanism 33 that changes the range of air blown to the pressure roller 22.

[0034] In this embodiment, the fans 31 are disposed one on each of both ends of the pressure roller 22 in the longitudinal direction. Here, in this specification, the "longitudinal direction" of the pressure roller refers to the direction of the arrow X shown in FIG. 4, and means the same direction as the rotation axis direction of the pressure roller, the longitudinal direction or rotation axis direction of the fixing roller, or the paper width direction intersecting with the paper passing direction in which the paper passes through the nip portion. Also, the "longitudinal direction" of the fixing belt in the following description means the same direction. Also, in this specification, the "longitudinal center side" means a position closer to the center in the longitudinal direction of the rotating body such as the pressure roller or the fixing roller than the "longitudinal both end sides" or the "longitudinal end side". However, the "longitudinal center side" does not necessarily mean an area including the center, and may be near the center excluding the center. Similarly, the "longitudinal both end sides" and the "longitudinal end sides" may be areas including the "both end sides" or the "ends", or may not include the "both end sides" or the "ends".

[0035] The duct 32 is disposed so as to extend from each fan 31 to the vicinity of the outer circumferential surface of the pressure roller 22. An air outlet 32a facing the outer circumferential surface of the pressure roller 22 is provided at the end of the duct 32 on the pressure roller 22 side. An air blowing range changing mechanism 33 is provided inside the duct 32. The air blowing range changing mechanism 33 includes a first partition member 34 and a second partition member 35.

[0036] The first partition member 34 is a duct-shaped member, and is disposed so as to face the outer peripheral surface of the pressure roller 22 on the longitudinal center side. The first partition member 34 is disposed so as to extend continuously from between the pair of fans 31 toward the outer peripheral surface of the pressure roller 22. Therefore, the first partition member 34 and the duct 32 form flow paths from each fan 31 toward both longitudinal ends of the pressure roller 22.

[0037] In this embodiment, the first partition member 34 has, in order from the upstream side in the air blowing direction of the fan 31, an upstream orthogonal surface 34a perpendicular to the longitudinal direction X of the pressure roller 22, an inclined surface 34b inclined with respect to the longitudinal direction X of the pressure roller 22, and a downstream orthogonal surface 34c perpendicular to the longitudinal direction X of the pressure roller 22. The inclined surfaces 34b are inclined toward both ends of the longitudinal direction of the pressure roller 22 toward the downstream side in the air blowing direction, so that the width of the flow path formed by the duct 32 and the first partition member 34 gradually narrows toward the downstream side.

[0038] The first partition member 34 is configured to be reciprocally movable in a direction intersecting or perpendicular to the longitudinal direction X of the pressure roller 22. That is, the first partition member 34 is configured to be able to move away from the outer circumferential surface of the pressure roller 22, or, conversely, to approach the outer circumferential surface of the pressure roller 22, as shown in Fig. 5. Note that the first partition member 34 is disposed in a non-contact state with the outer circumferential surface of the pressure roller 22 when it is close to the pressure roller 22, so as not to impede the rotation of the pressure roller 22 or cause wear of the pressure roller 22.

[0039] The second partition member 35 is a plate-like or block-like member disposed opposite the outer peripheral surface of the pressure roller 22 at the center in the longitudinal direction. Two second partition members 35 are disposed at an interval in the longitudinal direction X of the pressure roller 22. Similarly to the first partition member 34, the second partition member 35 is disposed so as not to contact the outer peripheral surface of the pressure roller 22. As shown in FIG. 4, when the first partition member 34 is disposed close to the pressure roller 22, the second partition member 35 is accommodated inside the first partition member 34. On the other hand, as shown in FIG. 5, when the first partition member 34 is separated from the pressure roller 22, the second partition member 35 is exposed to the outside of the first partition member 34.

[0040] 6, the second partition members 35 are configured to be reciprocatable in the longitudinal direction X of the pressure roller 22, and can move toward or away from each other. As a mechanism for moving the second partition members 35, for example, as shown in FIG. 7, a rack-and-pinion mechanism having racks 36 provided on the second partition members 35 and pinion gears 37 meshing with gear portions of the racks 36 can be used. When the pinion gears 37 rotate in the forward or reverse direction, the pair of racks 36 move linearly, and the second partition members 35 move toward or away from each other in the longitudinal direction X of the pressure roller 22.

[0041] Next, the relationship between the operation of air-blowing range change mechanism 33 and the air-blowing range will be described.

[0042] 4, when the first partition member 34 is close to the outer peripheral surface of the pressure roller 22, the airflow sent from each fan 31 is guided along the outer surface (upstream side orthogonal surface 34a, inclined surface 34b, downstream side orthogonal surface 34c) of the first partition member 34 and the inner surface of the duct 32. Therefore, the airflow is blown out from between the first partition member 34 and the duct 32, and is sent to the outer peripheral surface of the pressure roller 22 in the range L1 shown in FIG.

[0043] 5, when the first partition member 34 moves away from the outer circumferential surface of the pressure roller 22, the range in which air is blown onto the outer circumferential surface of the pressure roller 22 expands from L1 to L2. That is, near the outer circumferential surface of the pressure roller 22 on the downstream side in the air blowing direction, the wall formed by the first partition member 34 disappears, and instead the second partition member 35, which is disposed closer to the center in the longitudinal direction X than the first partition member 34, is exposed, so that the airflow can flow up to the position of the second partition member 35, and the air blowing range expands toward the center in the longitudinal direction X.

[0044] Furthermore, as shown in FIG. 6, when the second partition members 35 move toward the center in the longitudinal direction X with the first partition members 34 spaced apart, the air blowing range expands further toward the center, from L2 to L3.

[0045] As described above, in this embodiment, the air blowing range for the pressure roller 22 can be changed in the longitudinal direction X by appropriately moving the first partition member 34 and the second partition member 35. Therefore, even if the non-paper passing area changes depending on the width size of the paper, the air blowing range can be changed accordingly, and the temperature rise in the non-paper passing area can be effectively suppressed.

[0046] For example, when the largest paper P3 is passed through among the papers P1 to P3 each having a width smaller than the maximum paper P4 shown in Fig. 3, the air blowing range is set to the range L1 shown in Fig. 4 to correspond to the non-paper passing area B3. When the paper P2 having a width smaller than the paper P3 is passed through, the non-paper passing area increases from B3 to B2, so the air blowing range is expanded to the range L2 shown in Fig. 5 to correspond to the non-paper passing area B2. When the paper P1 having an even smaller width is passed through, the air blowing range is further expanded to the range L3 shown in Fig. 6, so that the air blowing range can be set to correspond to each of the non-paper passing areas B1 to B3. The change in the air blowing range is not limited to a three-step change, but may be two steps or four or more steps according to the paper size being passed through.

[0047] In this way, in this embodiment, the airflow range can be changed according to the paper size. Moreover, the change in the airflow range can be achieved with a simple configuration. This eliminates the need for a complex configuration for changing the airflow range, and reduces manufacturing costs and saves space.

[0048] 5 and 6, in a state in which the first partition member 34 is separated from the pressure roller 22 and the second partition member 35 is exposed, it is preferable that there is no gap between the first partition member 34 and the second partition member 35 in the air blowing direction in order to prevent the airflow from flowing in from between the first partition member 34 and the second partition member 35 toward the center in the longitudinal direction. That is, it is preferable that the upstream end of the second partition member 35 in the air blowing direction (upward in Figs. 5 and 6) is disposed at the downstream end of the first partition member 34 or so as to enter the first partition member 34 from there. This makes it possible to prevent the airflow from flowing in from between the first partition member 34 and the second partition member 35 toward the center in the longitudinal direction X, and allows air to be effectively blown to both ends of the pressure roller 22 in the longitudinal direction X.

[0049] In addition to changing the blowing range as described above, the air volume of the fan may be changed. Here, "air volume" refers to the amount of air that the blowing device (fan) moves per unit time, and the air volume Q (m 3 / h) is the function of the passing wind speed V (m / s) and the passing area A (m 2 Specifically, the air volume can be measured using a hot wire anemometer or a vane anemometer.

[0050] An example of changing the airflow volume will be described below with reference to the timing chart shown in FIG.

[0051] In Fig. 8, TH1 is the temperature at the center of the fixing roller in the longitudinal direction (paper passing area), and TH2 is the temperature at the end of the fixing roller in the longitudinal direction (non-paper passing area). As shown in Fig. 8, when the temperature TH1 at the center of the fixing roller rises to a predetermined temperature t, printing operations such as image formation on the photoconductor and paper feeding are started. At this time, the rotation speed of the fan blowing air to the pressure roller is set to the lowest R1.

[0052] Here, when a small size paper is passed through, heat is not easily absorbed by the paper in the non-paper passing area, so heat is stored and the end side temperature TH2 of the fixing roller becomes higher than the center side temperature TH1. Then, when the difference between the center side temperature TH1 and the end side temperature TH2 becomes ΔT1, the rotation speed of the fan is switched from the rotation speed R1 to the higher rotation speed R2. After that, when the end side temperature TH2 further increases and the difference between the center side temperature TH1 and the end side temperature TH2 becomes ΔT10, the rotation speed of the fan is switched to the rotation speed R3 which is higher than the rotation speed R2. After that, the end side temperature TH2 decreases, and the blowing operation at the high rotation speed R3 continues until the difference between the center side temperature TH1 and the end side temperature TH2 becomes ΔT2. Then, when the difference between the center side temperature TH1 and the end side temperature TH2 becomes ΔT2, the rotation speed of the fan is switched from R3 to the lower rotation speed R2. After that, when the printing operation is completed and the image forming apparatus is in a standby state, the halogen heater in the fixing device stops generating heat, and the end temperature TH2 further decreases. Then, in the standby state, when the difference between the center temperature TH1 and the end temperature TH2 becomes ΔT1, the fan rotation speed is switched to R1, which is lower than R2.

[0053] In this way, when the temperature TH2 at the end side, which is the non-paper passing area, is relatively higher than the temperature TH1 at the center side, which is the paper passing area, the temperature rise in the non-paper passing area can be effectively suppressed by increasing the fan rotation speed and air volume. Therefore, in addition to changing the air blowing range as described above, by changing the air volume of the fan based on the temperature difference between the longitudinal center side and the longitudinal end side of the fixing roller, it is possible to more effectively cool the non-paper passing area.

[0054] In the above example, the air volume is changed based on the temperature of the fixing roller, but the air volume may be changed based on the temperature of the pressure roller. In addition, in a standby state where no printing operation is being performed, the rotation speed of the fan may be set to a low rotation speed R1, or the rotation of the fan may be stopped.

[0055] In addition, in the present invention, the orientation and arrangement of the fan 31 may be the orientation and arrangement shown in Fig. 9 or 10, in addition to the orientation and arrangement shown in Fig. 4. That is, the fan 31 may be arranged so as to blow air in a direction perpendicular to the longitudinal direction X of the pressure roller 22 as shown in Fig. 4, or may be arranged so as to blow air in a direction oblique to the longitudinal direction X of the pressure roller 22 as shown in Fig. 9, or so as to blow air in a direction parallel to the longitudinal direction X of the pressure roller 22 as shown in Fig. 10. In this way, the orientation and arrangement of the fan can be changed as appropriate depending on the layout of components in the image forming apparatus, and the same actions and effects as those of the above embodiment can be expected even if the orientation and arrangement of the fan are changed.

[0056] The blower according to the present invention is not limited to blowing air to the pressure roller 22, but may blow air to the fixing roller 21 as in the example shown in Fig. 11. Also, as in the example shown in Fig. 12, blower devices 30 may be disposed on both sides of the fixing roller 21 and the pressure roller 22, and each blower device 30 may blow air to both the fixing roller 21 and the pressure roller 22.

[0057] In addition, the present invention is not limited to image forming devices using a so-called center-based transport method, in which sheets of paper of various width sizes are transported based on the center of each sheet in the width direction as shown in FIG. 3, but can also be applied to image forming devices using a so-called end-based transport method, in which sheets of paper P1 to P4 of different widths W1 to W4 are transported based on one end of each sheet in the width direction as shown in FIG. 13.

[0058] Specifically, as shown in Fig. 14, the first partition member 34 is disposed close to one end side in the longitudinal direction X of the pressure roller 22. Also, in this case, one second partition member 35 is sufficient. By moving the first partition member 34 disposed in this manner closer to or farther from the outer circumferential surface of the pressure roller 22 or by moving the second partition member 35 in the longitudinal direction X of the pressure roller 22, the air blowing range can be changed according to the size of the paper being passed. Also, in Fig. 14, the air blowing device 30 may be disposed on the fixing roller 21 side.

[0059] The configuration of the fixing device is not limited to that of the above embodiment. For example, the fixing device may be configured to include an endless fixing belt 25 as a fixing rotator, a pressure roller 26 as a pressure rotator, a heater 27 as a heat source, a heater holder 28 as a heat source holding member for holding the heater 27, and a stay 29 as a support member for supporting the heater holder 28, as shown in FIG. 15. In this case, the pressure roller 26 is pressed against the heater 27 via the fixing belt 25, so that a nip N is formed between the fixing belt 25 and the pressure roller 26. In such a fixing device 20, the air blowing range can be changed in the longitudinal direction of the fixing belt 25 or the pressure roller 26 by disposing the air blowing device according to the present invention in the same manner as in the above embodiment, and the change in the air blowing range can be realized by a simple configuration.

[0060] The blower device according to the present invention is not limited to blowing air to a fixing device. For example, the blower device according to the present invention can be applied to a drying device (heating device) that heats paper in order to dry liquid such as ink discharged onto the paper in an inkjet image forming apparatus. [Explanation of symbols]

[0061] 20 Fixing device (heating device) 21 Fixing roller (rotating body) 22 Pressure roller (rotating body) 30 Blower 31 Fan (airflow generating component) 32 Duct (flow path forming member) 33 Airflow range change mechanism 34 First partition member 35 Second partition member 100 Image forming device P Paper (recording medium) X Longitudinal direction [Prior art documents] [Patent documents]

[0062] [Patent Document 1] JP 2006-119259 A

Claims

1. A blower that blows air onto a rotating body included in a heating device that heats a recording medium on which an image is formed, an airflow generating member that generates an airflow to be blown onto the outer circumferential surface of the rotating body; An air blowing range changing mechanism is provided for changing the range of the air blown onto the outer circumferential surface of the rotor in the direction of the rotation axis or the longitudinal direction of the rotor, The air blowing range change mechanism is a first partition member that faces an outer peripheral surface of the rotor and is movable toward and away from the outer peripheral surface of the rotor in a direction different from a rotation axis direction of the rotor or a direction different from a longitudinal direction of the rotor; A blower device comprising: a second partition member opposed to an outer peripheral surface of the rotor and movable in a direction of a rotation axis or a longitudinal direction of the rotor.

2. A blower that blows air to a rotating body provided in a heating device that heats a recording medium on which an image is formed, an airflow generating member that generates an airflow to be blown onto the outer circumferential surface of the rotating body; An air blowing range changing mechanism is provided for changing the range of the air blown onto the outer circumferential surface of the rotor in the direction of the rotation axis or the longitudinal direction of the rotor, The air blowing range change mechanism is A first partition member that faces an outer circumferential surface of the rotating body and is movable in a direction toward and away from the outer circumferential surface of the rotating body; a second partition member that faces an outer circumferential surface of the rotor and is movable in a rotation axis direction or a longitudinal direction of the rotor, A blower device characterized in that the second partition member is accommodated inside the first partition member when the first partition member is close to the outer peripheral surface of the rotating body, and is exposed outside the first partition member when the first partition member is separated from the outer peripheral surface of the rotating body.

3. A blower that blows air to a rotating body provided in a heating device that heats a recording medium on which an image is formed, an airflow generating member that generates an airflow to be blown onto the outer circumferential surface of the rotating body; An air blowing range changing mechanism is provided for changing the range of the air blown onto the outer circumferential surface of the rotor in the direction of the rotation axis or the longitudinal direction of the rotor, The air blowing range change mechanism is A first partition member that faces an outer circumferential surface of the rotating body and is movable in a direction toward and away from the outer circumferential surface of the rotating body; a second partition member that faces an outer circumferential surface of the rotor and is movable in a rotation axis direction or a longitudinal direction of the rotor, the first partition member and the second partition member are disposed on a central side in a rotation axis direction or a longitudinal direction of the rotating body, The air flow is blown toward both ends of the rotating body in the direction of the rotation axis or the longitudinal direction relative to the first partition member and the second partition member.

4. The second partition member is arranged in two pieces, The blower device according to claim 3 , wherein the two second partition members are movable toward and away from each other in a direction of a rotation axis or a longitudinal direction of the rotor.

5. The blower device according to claim 1 , wherein the positions of the first partition member and the second partition member are changed according to a width of the recording medium.

6. The blower device according to claim 1 , wherein the airflow generating member is capable of changing an air volume based on a temperature difference between a center side and an end side in a rotation axis direction or a longitudinal direction of the rotor.

7. 7. The blower device according to claim 1, wherein the airflow generating member is disposed so as to blow air in a direction perpendicular to, oblique to, or parallel to a rotational axis or longitudinal direction of the rotor.

8. a heating device having a rotating body and configured to heat the recording medium on which an image is formed; An image forming apparatus comprising the air blower according to claim 1 for blowing air to the heating device.

9. 9. The image forming apparatus according to claim 8, wherein the rotating body is a pressure roller or a fixing belt.

Images