JP2023001590A - Air blowing device and image forming apparatus - Google Patents

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

The present invention relates to an air blower and an image forming apparatus.

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 fixes an image on the paper by heating the paper while sandwiching it between a pair of rotating bodies such as endless belts or rollers. ing.

In the fixing device, the heat in the non-paper-passing area where the paper does not pass tends to be less likely to be lost by the paper. However, there is a problem that the temperature rise becomes remarkable. In order to address such a problem, in a conventional fixing device, a fan or the like is used to blow air to the non-paper-passing area of the rotating body, thereby suppressing the temperature rise in the non-paper-passing area.

Further, the range of temperature rise in the non-sheet-passing area as described above differs depending on the size of the sheet to be passed. For this reason, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-119259), a pair of plate-like members provided in a duct are opened and closed to allow cooling air to flow through the fixing roller according to the size of the paper. It has been proposed to change the configuration in the longitudinal direction.

However, in the case of the configuration proposed by the above-mentioned Patent Document 1, in order to open and close the pair of plate-shaped bodies, it is necessary to provide a guide for guiding each plate-shaped body in addition to a drive mechanism including a nut and a shaft. Therefore, there is a problem that the configuration becomes complicated and it is difficult to simplify the configuration.

In order to solve the above-described problems, the present invention provides a blower for blowing air to a rotating body provided in a heating device for heating a recording medium on which an image is formed, wherein the airflow blown to the outer peripheral surface of the rotating body is and an airflow range changing mechanism for changing the range of air blown to the outer peripheral surface of the rotating body in the rotational axis direction or the longitudinal direction of the rotating body, wherein the airflow range changing mechanism a first partition member that faces the outer peripheral surface of the rotating body and is movable in a direction toward and away from the outer peripheral surface of the rotating body; It is characterized by comprising a movable second partition member.

ADVANTAGE OF THE INVENTION According to this invention, a ventilation range can be changed in the rotating shaft direction or a longitudinal direction of a rotating body by simple structure.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention; FIG. 1 is a schematic configuration diagram of a fixing device according to an exemplary embodiment; FIG. 4A and 4B are diagrams showing a paper passing area and a paper non-passing area in the fixing device; FIG. It is a figure which shows the structure of the air blower which concerns on this embodiment. FIG. 10 is a diagram showing a state in which the first partition member is spaced apart from the pressure roller; FIG. 10 is a diagram showing a state in which the second partition member has moved toward the center in the longitudinal direction of the pressure roller; It is a figure which shows the moving mechanism of a 2nd partition member. It is a figure which shows the timing chart which changes the air volume of a fan. FIG. 10 is a diagram showing another example in which the direction and placement of the fan are different; FIG. 10 is a diagram showing yet another example with different fan orientations and placements; FIG. 5 is a diagram showing an example in which a blower is arranged on the fixing roller side; FIG. 4 is a diagram showing an example in which blowers are arranged on both the fixing roller side and the pressure roller side; 1 is a diagram illustrating an example of an image forming apparatus using an edge-based conveyance method; FIG. FIG. 2 is a diagram showing an example in which the present invention is applied to an image forming apparatus using an edge-based conveyance method; and FIG. 9 is a diagram showing another example of a fixing device to which the present invention can be applied.

The present invention will be described below with reference to the accompanying drawings. In addition, in each drawing for explaining the present invention, constituent elements such as members and constituent parts having the same function or shape are given the same reference numerals as much as possible, and once explained, the explanation will be repeated. omitted.

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to one embodiment of the present invention. Here, the "image forming apparatus" in this specification includes a printer, a copier, a facsimile machine, a printing machine, or a multifunction machine combining two or more of these. Further, the term "image formation" used in the following description means not only formation of meaningful images such as characters and graphics, but also formation of meaningless images such as patterns. First, referring to FIG. 1, the overall configuration and operation of the image forming apparatus according to this embodiment will be described.

As shown in FIG. 1, the image forming apparatus 100 according to the present embodiment includes an image forming section 200 that forms an image on a sheet-like recording medium such as paper, a fixing section 300 that fixes the image on the recording medium, A recording medium supply unit 400 for supplying a recording medium to the image forming unit 200 and a recording medium discharge unit 500 for discharging the recording medium to the outside of the apparatus are provided.

The image forming section 200 includes four process units 1Y, 1M, 1C, and 1Bk as image forming units, and an exposure device for forming an electrostatic latent image on the photosensitive member 2 provided in each of the process units 1Y, 1M, 1C, and 1Bk. 6 and a transfer device 8 for transferring an image onto a recording medium.

Each of the process units 1Y, 1M, 1C, and 1Bk has basically the same configuration except that it accommodates different color toners (developers) of yellow, magenta, cyan, and black corresponding to color separation components of a color image. be. Specifically, each of the process units 1Y, 1M, 1C, and 1Bk includes a photoreceptor 2 as an image carrier that carries an image on its surface, a charging member 3 that charges the surface of the photoreceptor 2, and a surface of the photoreceptor 2. and a cleaning member 5 for cleaning the surface of the photoreceptor 2 .

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 . A primary transfer nip is formed between the intermediate transfer belt 11 and each photoreceptor 2 by bringing each primary transfer roller 12 into contact with each photoreceptor 2 via the intermediate transfer belt 11 . The secondary transfer roller 13 contacts the outer peripheral surface of the intermediate transfer belt 11 to form a secondary transfer nip.

A fixing device 20 is provided in the fixing section 300 . The fixing device 20 includes a fixing roller 21 as a fixing member, a pressure roller 22 as a pressure member, and the like. The fixing roller 21 and the pressure roller 22 are pressed against each other, and a nip portion (fixing nip) is formed between these rollers 21 and 22 .

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 the paper P from the paper feed cassette 14 . Hereinafter, 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 OHP sheets or fabrics, metal sheets, plastic films, or prepreg sheets in which carbon fibers are previously impregnated with resin. In addition to plain paper, "paper" includes thick paper, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and the like.

The recording medium discharge unit 500 is provided with a pair of paper discharge rollers 17 for discharging the paper P to the outside of the image forming apparatus, and a paper discharge tray 18 for placing the paper P discharged by the paper discharge rollers 17 .

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

When the image forming apparatus 100 starts printing, the photosensitive members 2 of the process units 1Y, 1M, 1C, and 1Bk and the intermediate transfer belt 11 of the transfer device 8 start rotating. Also, the paper feed roller 15 starts rotating, and the paper P is sent out from the paper feed cassette 14 . The sent paper P comes into contact with the pair of timing rollers 16 to stand still, and the transportation of the paper P is temporarily stopped until an image to be transferred to the paper P is formed.

In each of the process units 1Y, 1M, 1C, and 1Bk, the charging member 3 first charges the surface of the photoreceptor 2 to a uniform high potential. Next, the exposure device 6 exposes the surface (charged surface) of each photoreceptor 2 based on the image information of the document read by the document reading device or the print image information instructed to print from the terminal. As a result, the potential of the exposed portion is lowered and an electrostatic latent image is formed on the surface of each photoreceptor 2 . Then, the developing device 4 supplies toner to this electrostatic latent image, and a toner image is formed on each photosensitive member 2 . The toner images formed on each photoreceptor 2 are transferred onto the rotating intermediate transfer belt 11 so as to overlap one another when they reach the primary transfer nip (the position of the primary transfer roller 12) as each photoreceptor 2 rotates. be done. Thus, a full-color toner image is formed on the intermediate transfer belt 11 . Note that the image forming apparatus 100 uses any one of the process units 1Y, 1M, 1C, and 1Bk to form a monochrome image, or uses any two or three process units to form a two-color or three-color image. Color images can also be formed. Further, after the toner image is transferred from the photoreceptor 2 to the intermediate transfer belt 11 , residual toner on each photoreceptor 2 is removed by the cleaning member 5 .

The toner image transferred onto the intermediate transfer belt 11 is conveyed 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 conveyed by the timing roller 16. transcribed to After that, the paper P is conveyed to the fixing device 20 , and the toner image on the paper P is fixed to the paper P by heating and pressing the toner image on the paper P by the fixing roller 21 and the pressure roller 22 . Then, the paper P is conveyed to the recording medium discharge section 500 and discharged to the paper discharge tray 18 by the paper discharge rollers 17 . This completes a series of printing operations.

Next, the configuration of the fixing device 20 according to this embodiment will be described with reference to FIG.

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

The fixing roller 21 is a rotating body (first rotating body) that functions as a fixing member that fixes the unfixed toner T on the paper P. As shown in FIG. The fixing roller 21 has, for example, an aluminum substrate with an outer diameter of 30 mm and a thickness of 0.7 mm. The material of the substrate may be other metallic materials such as iron other than aluminum. 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 on the outer peripheral surface of the substrate in order to ensure durability and releasability. Further, an elastic layer made of rubber or the like may be provided between the substrate and the release layer.

The pressure roller 22 is a rotating body (second rotating body) arranged to face the fixing roller 21 . The pressure roller 22 is also a pressure member that forms the nip portion N by being pressed by the fixing roller 21 . The pressure roller 22 is pressed against the outer peripheral surface of the fixing roller 21 by an urging member such as a spring. As a result, a nip portion N is formed between the fixing roller 21 and the pressure roller 22 (contact portion). The pressure roller 22 has an outer diameter of 30 mm, for example, and has a solid iron core, an elastic layer provided on the outer peripheral surface of the core, and a release layer provided on the outer peripheral surface of the elastic layer. are doing. The elastic layer has a thickness of 10 mm, for example, and is made of silicone rubber or the like. The release layer has a thickness of about 30 μm, for example, and is made of a fluororesin such as PFA or PTFE.

A halogen heater 23 is arranged inside the fixing roller 21 . The heat generated by the halogen heater 23 heats the fixing roller 21 from the inside. Further, as a heat source for heating the fixing roller 21, in addition to the halogen heater 23, a carbon heater, a ceramic heater, or an IH (electromagnetic induction heating) type heat source can be used.

The output (the amount of heat generated) 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 sensor that is arranged in a non-contact manner with respect to the fixing roller 21 , the temperature sensor 24 detects the ambient temperature in the vicinity of the fixing roller 21 as the temperature of the fixing roller 21 . Also, the temperature sensor 24 may be a contact 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, thermostat, thermistor or NC sensor can be applied.

By controlling the output of the halogen heater 23 based on the temperature detected by the temperature sensor 24, the temperature of the fixing roller 21 is maintained at a predetermined temperature. In this state, as shown in FIG. 2, when the sheet P carrying the unfixed toner T enters between the fixing roller 21 and the pressure roller 22 (the nip portion N), the fixing roller 21 and the pressure roller 22 pressurizes and heats the unfixed toner T to fix the toner image on the paper P. FIG.

Here, as shown in FIG. 3, the fixing device 20 according to the present embodiment is configured to be able to pass sheets P1 to P4 of various width sizes. The halogen heater 23 is arranged over the entire maximum sheet passing area (maximum recording medium passing area) A through which the sheet P4 having the maximum width W4 passes so that any sheet can be heated. there is

However, if the halogen heater 23 is arranged over the entire maximum paper passing area A, when various types of paper P1 to P3 having widths smaller than the maximum width paper P4 are passed, these papers P1 to P3 In the non-paper-passing areas (recording-medium non-passing areas) B1 to B3 through which the recording medium does not pass, heat is accumulated because it is difficult for heat to be consumed. Therefore, in the non-paper-passing areas B1 to B3, the temperature rises more easily than in the paper-passing areas. In particular, when a plurality of various types of small-width paper P1 to P3 are continuously passed, the temperature rise in each non-paper-passing area B1 to B3 becomes remarkable. may exceed the heat-resistant temperature.

This problem of temperature rise in the paper non-passage area can be improved by blowing air to the paper non-passage area using an air blower such as a fan. However, the range of temperature rise in the non-sheet-passing area differs according to the size of the sheet to be passed. Therefore, in order to effectively suppress the temperature rise in the non-sheet-passing area, it is necessary to change the blowing range according to the sheet size. Therefore, in this embodiment, the blowing range can be changed by adopting the following configuration.

The configuration of the air blower according to the present embodiment will be described below with reference to FIGS. 4 to 7. FIG.

As shown in FIG. 4, the blower device 30 according to this embodiment includes a fan 31 as an airflow generating member that generates an airflow, and a flow path for guiding the airflow generated by the fan 31 to the pressure roller 22. and a blowing range changing mechanism 33 for changing the blowing range to the pressure roller 22 .

In the present embodiment, the fans 31 are arranged one by one on both ends of the pressure roller 22 in the longitudinal direction. Here, in this specification, the "longitudinal direction" of the pressure roller means the direction of the arrow X shown in FIG. Alternatively, it means the same direction as the paper width direction that intersects the paper feeding 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. In this specification, the term “longitudinal center” refers to a position closer to the longitudinal center of a rotating body such as a pressure roller or a fixing roller than “both ends in the longitudinal direction” or “ends in the longitudinal direction”. means. However, the "longitudinal center side" does not necessarily mean the region including the center, and may be the vicinity of the center excluding the center. Similarly, the “both ends in the longitudinal direction” and the “ends in the longitudinal direction” may be regions that include “both ends” or “ends”, or regions that do not include “both ends” or “ends”. may be

The duct 32 is arranged so as to extend from each fan 31 to near the outer peripheral surface of the pressure roller 22 . An end of the duct 32 on the pressure roller 22 side is provided with an air blowing port 32 a facing the outer peripheral surface of the pressure roller 22 . A ventilation range changing mechanism 33 is provided in the duct 32 . The blowing range changing mechanism 33 includes a first partition member 34 and a second partition member 35 .

The first partition member 34 is a duct-shaped member, and is arranged so as to face the outer peripheral surface of the pressure roller 22 on the central side in the longitudinal direction. Further, the first partition member 34 is arranged so as to continuously extend from between the pair of fans 31 toward the outer peripheral surface of the pressure roller 22 . For this reason, the first partition member 34 and the duct 32 form flow paths extending from each fan 31 to both ends in the longitudinal direction of the pressure roller 22 .

In this embodiment, the first partition member 34 includes, in order from the upstream side of the blowing direction of the fan 31 , an upstream orthogonal surface 34 a orthogonal to the longitudinal direction X of the pressure roller 22 , and the longitudinal direction of the pressure roller 22 . It has an inclined surface 34 b inclined with respect to the direction X and a downstream orthogonal surface 34 c orthogonal to the longitudinal direction X of the pressure roller 22 . Since the inclined surface 34b is inclined toward both longitudinal end sides of the pressure roller 22 toward the downstream in the blowing direction, the width of the flow path formed by the duct 32 and the first partition member 34 gradually increases toward the downstream. narrowed to

Further, 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, as shown in FIG. 5, the first partition member 34 is configured so that it can be separated from the outer peripheral surface of the pressure roller 22 and, conversely, can approach the outer peripheral surface of the pressure roller 22. It is In addition, the first partition member 34 is placed close to the pressure roller 22 so as not to hinder the rotation of the pressure roller 22 or cause the pressure roller 22 to wear. It is arranged in a non-contact manner with respect to the

The second partition member 35 is a plate-shaped or block-shaped member arranged to face the outer peripheral surface of the pressure roller 22 on the central side in the longitudinal direction. Two second partition members 35 are arranged with an interval in the longitudinal direction X of the pressure roller 22 . Further, the second partition member 35 is arranged so as not to come into contact with the outer peripheral surface of the pressure roller 22 , like the first partition member 34 . As shown in FIG. 4 , when the first partition member 34 is arranged close to the pressure roller 22 , the second partition member 35 is housed inside the first partition member 34 . On the other hand, when the first partition member 34 is separated from the pressure roller 22 as shown in FIG. 5, the second partition member 35 is exposed to the outside of the first partition member 34 .

Also, as shown in FIG. 6, the second partition member 35 is configured to be reciprocatable in the longitudinal direction X of the pressure roller 22, and can approach or separate from each other. As a mechanism for moving the second partition member 35, for example, as shown in FIG. A pinion mechanism can be adopted. By rotating the pinion gear 37 in the forward or reverse direction, the pair of racks 36 linearly moves, and the respective second partition members 35 approach or separate from each other in the longitudinal direction X of the pressure roller 22 .

Next, the relationship between the operation of the blowing range changing mechanism 33 and the blowing range will be described.

First, as shown in FIG. 4, in a state where the first partition member 34 is close to the outer peripheral surface of the pressure roller 22, the airflow blown from each fan 31 is It is guided along the outer surface (upstream orthogonal surface 34 a , inclined surface 34 b , downstream orthogonal surface 34 c ) 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 blown to the outer peripheral surface of the pressure roller 22 in the range L1 shown in FIG.

Next, as shown in FIG. 5, when the first partition member 34 is separated from the outer peripheral surface of the pressure roller 22, the range in which air is blown to the outer peripheral surface of the pressure roller 22 expands from L1 to L2. . That is, in the vicinity of the outer peripheral surface of the pressure roller 22 on the downstream side in the blowing direction, the wall formed by the first partition member 34 is eliminated, and instead, the second partition is arranged closer to the center in the longitudinal direction X than the first partition member 34 is. Since the member 35 is exposed, the airflow can flow up to the position of the second partition member 35, and the blowing range spreads toward the center in the longitudinal direction X.

Further, as shown in FIG. 6, when each of the second partition members 35 is moved toward the center in the longitudinal direction X with the first partition members 34 separated, the blowing range expands further toward the center, extending from L2 to L3. becomes.

As described above, in the present embodiment, the range of blowing air to 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 paper non-passing area changes according to the width size of the paper, the blowing range can be changed accordingly, and the temperature rise in the paper non-passing area can be effectively suppressed.

For example, among the sheets P1 to P3 having widths smaller than the maximum width sheet P4 shown in FIG. , the blowing range is set to the range L1 shown in FIG. Also, when the paper P2 having a width smaller than that of the paper P3 is passed, the non-paper-passing area increases from B3 to B2. Expand to the indicated range L2. Then, when the paper P1 having a smaller width is to be passed, the blowing range is further widened to the range L3 shown in FIG. can. Note that the change in the blowing range is not limited to three steps, and may be two steps or four steps or more corresponding to the paper size to be passed.

As described above, in this embodiment, the blowing range can be changed according to the paper size. Moreover, it is possible to change the blowing range with a simple configuration. This eliminates the need for a complicated configuration for changing the blowing range, thereby reducing manufacturing costs and saving space.

As shown in FIGS. 5 and 6, when the first partition member 34 is separated from the pressure roller 22 and the second partition member 35 is exposed, the air currents flow through the first partition member 34. It is preferable that there is no space between the first partition member 34 and the second partition member 35 in the blowing direction in order to prevent the air from flowing into the center in the longitudinal direction from the space between the first partition member 34 and the second partition member 35 . That is, the upstream end of the second partition member 35 in the blowing direction (upward direction in FIGS. 5 and 6) is located at the position of the downstream end of the first partition member 34 or so as to enter the first partition member 34 from there. is preferably placed in the As a result, it is possible to suppress the flow of the airflow from between the first partition member 34 and the second partition member 35 toward the center in the longitudinal direction X, thereby effectively blowing air to both ends of the pressure roller 22 in the longitudinal direction X. can.

In addition to changing the blowing range as described above, the air volume of the fan may be changed. Here, the “air volume” is the amount of air moved by the blower (fan) per unit time, and the air volume Q (m ³ /h) is the passing air velocity V (m/s) and the passing area A It is represented by a multiplier of (m ² ). Specifically, the air volume can be measured using a hot-wire anemometer, a vane anemometer, or the like.

An example of changing the air volume will be described below with reference to the timing chart shown in FIG.

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 central temperature TH1 of the fixing roller rises to a predetermined temperature t, printing operations such as an image forming operation on the photosensitive member and a paper feeding operation are started. At this time, the rotational speed of the fan blowing air to the pressure roller is set to the lowest R1.

Here, when a small size sheet is passed, the heat is not easily removed by the sheet in the non-sheet-passing area, so heat is accumulated, and the end-side temperature TH2 of the fixing roller becomes higher than the center-side temperature TH1. Then, when the difference between the central temperature TH1 and the end 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 edge temperature TH2 further increases and the difference between the center temperature TH1 and the edge temperature TH2 becomes ΔT10, the fan rotation speed is switched to the rotation speed R3, which is higher than the rotation speed R2. be done. After that, the air blowing operation at the high rotational speed R3 is continued until the end-side temperature TH2 decreases and the difference between the center-side temperature TH1 and the end-side temperature TH2 becomes ΔT2. Then, when the difference between the central temperature TH1 and the end temperature TH2 reaches 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 enters a standby state, heat generation of the halogen heater in the fixing device also stops, so the end-side temperature TH2 further decreases. Then, in the standby state, 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 to R1, which is lower than R2.

In this way, when the temperature TH2 of the end side, which is the non-paper-passing area, is relatively higher than the temperature TH1 of the central side, which is the paper-passing area, the rotation speed of the fan is increased to increase the air volume. As a result, it is possible to effectively suppress the temperature rise in the non-sheet-passing area. 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, more effective cooling of the non-paper-passing area can be achieved. becomes possible.

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. Further, in a standby state in which no printing operation is 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.

Moreover, 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. That is, the fan 31 blows air in the direction perpendicular to the longitudinal direction X of the pressure roller 22 as shown in FIG. 10, or in a direction parallel to the longitudinal direction X of the pressure roller 22 as shown in FIG. In this way, the orientation and arrangement of the fan can be changed as appropriate according to the layout of parts in the image forming apparatus, and even if the orientation and arrangement of the fan are changed, the same actions and effects as in the above embodiment can be expected.

Further, the air blowing device according to the present invention is not limited to blowing air to the pressure roller 22, and may blow air to the fixing roller 21 as in the example shown in FIG. Further, as in the example shown in FIG. 12, the air blower 30 is arranged on both sides of the fixing roller 21 and the pressure roller 22, and each air blower 30 blows air to both the fixing roller 21 and the pressure roller 22. good too.

In addition, the present invention is not limited to the image forming apparatus of the so-called center reference transport method in which sheets of various width sizes are transported with the center in the width direction as a reference, as shown in FIG. As shown, the present invention can also be applied to an image forming apparatus of a so-called edge reference transport system in which sheets P1 to P4 of different widths W1 to W4 are transported with one end in the width direction as a reference.

Specifically, as shown in FIG. 14 , the first partition member 34 is arranged closer to one end side of the pressure roller 22 in the longitudinal direction X. As shown in FIG. In this case, one second partition member 35 is sufficient. By moving the first partition member 34 arranged in this manner toward or away from the outer peripheral 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 blowing range can be changed according to the size of the paper to be passed. Further, in FIG. 14, the blower device 30 may be arranged on the fixing roller 21 side.

Further, the configuration of the fixing device is not limited to that of the above embodiment. For example, the fixing device, as shown in FIG. A configuration including a heater holder 28 as a heat source holding member to be held and a stay 29 as a support member for supporting the heater holder 28 may be employed. In this case, a nip portion N is formed between the fixing belt 25 and the pressure roller 26 by pressing the pressure roller 26 against the heater 27 via the fixing belt 25 . In such a fixing device 20 as well, by arranging the blower according to the present invention in the same manner as in the above embodiment, the blowing range can be changed in the longitudinal direction of the fixing belt 25 or the pressure roller 26, and the blowing range can be changed. can be realized by a simple configuration.

Further, the air blowing device according to the present invention is not limited to blowing air to the fixing device. For example, the air blower according to the present invention can also be applied to a drying device (heating device) for heating paper to dry liquid such as ink ejected onto paper in an inkjet image forming apparatus. .

20 fixing device (heating device)
21 fixing roller (rotating body)
22 pressure roller (rotating body)
30 air blower 31 fan (airflow generating member)
32 duct (flow passage forming member)
33 Blowing range changing mechanism 34 First partition member 35 Second partition member 100 Image forming apparatus P Paper (recording medium)
X longitudinal direction

JP 2006-119259 A

Claims (9)

A blowing device for blowing air to a rotating body provided in a heating device for heating a recording medium on which an image is formed,
an airflow generating member that generates an airflow blown to the outer peripheral surface of the rotating body;
A blowing range changing mechanism for changing the range of air blown to the outer peripheral surface of the rotating body in the rotation axis direction or the longitudinal direction of the rotating body,
The blowing range changing mechanism is
a first partition member facing the outer peripheral surface of the rotating body and movable in a direction toward and away from the outer peripheral surface of the rotating body;
A blower device comprising a second partition member facing the outer peripheral surface of the rotating body and movable in the rotating shaft direction or the longitudinal direction of the rotating body. The second partition member is accommodated inside the first partition member in a state in which the first partition member is close to the outer peripheral surface of the rotating body, and the first partition member is located on the outer peripheral surface of the rotating body. 2. The blower device according to claim 1, wherein the air blower is exposed to the outside of the first partition member in a state of being separated from the first partition member. The first partition member and the second partition member are arranged on the central side in the rotation axis direction or the longitudinal direction of the rotor,
The air blower according to claim 1 or 2, wherein the airflow is blown toward both end sides in a rotation axis direction or a longitudinal direction of the rotor rather than the first partition member and the second partition member. Two second partition members are arranged,
4. The blower device according to claim 3, wherein the two second partition members are movable toward and away from each other in the axial direction or longitudinal direction of the rotor. 5. The blower device according to claim 1, wherein positions of the first partition member and the second partition member are changed according to the width of the recording medium. The air blower according to any one of claims 1 to 5, wherein the air flow generating member can change the air volume based on the temperature difference between the central side and the end side in the rotating shaft direction or longitudinal direction of the rotating body. 7. The airflow generating member is arranged to blow air in any one of a direction perpendicular to, an oblique direction, and a direction parallel to the rotation axis direction or the longitudinal direction of the rotor. 1. The air blower according to item 1. a heating device that has a rotating body and heats a recording medium on which an image is formed;
An image forming apparatus comprising the air blower according to any one of claims 1 to 7, which blows air to the heating device. 9. The image forming apparatus according to claim 8, wherein the rotating body is a pressure roller or a fixing belt.

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