Image forming apparatus

Abstract

To reduce adhesion of waste powder recovered by a recovery unit compared with a case where there is no member to insulate heat between a fixing unit and the recovery unit.SOLUTION: An image forming apparatus comprises: an image forming unit that forms a toner image on a recording material by using developer including toner; a fixing unit that fixes the toner image formed by the image forming unit to the recording material; a recovery unit that recovers waste powder including toner discharged from the image forming unit; and an air circulation unit that allows circulation of air for cooling the periphery of the image forming unit or the fixing unit, and has a portion arranged between the recovery unit and the fixing unit.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Patent Document 1 discloses an image forming apparatus provided with a ventilation duct between a fixing unit and a cleaning unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a recovery unit that recovers waste powder containing waste toner discharged from an image forming unit, when facing a fixing unit that fixes a toner image onto a recording material, the waste powder may melt and adhere due to the heat generated in the fixing unit. An object of the present invention is to suppress the adhesion of waste powder recovered in the recovery unit as compared with the case where there is no member for heat insulation between the fixing unit and the recovery unit.

Means for Solving the Problems

[0005] The invention according to claim 1 Includes an image holder that holds the toner image and moves in a circulating manner, an image forming unit that forms a toner image on a recording material using a developer containing toner, a fixing unit that fixes the toner image formed by the image forming unit onto the recording material, A cleaning unit for cleaning the waste powder from the image holder of the image forming unit. a recovery unit that recovers waste powder containing toner discharged from the image forming unit Received from the aforementioned cleaning department and a gas flow unit having a portion disposed between the recovery unit and the fixing unit through which a gas for cooling the periphery of the image forming unit or the fixing unit flows 、 is provided The recovery unit includes a receiving unit for receiving waste powder from the cleaning unit, and transports the waste powder received from the cleaning unit by dropping it into a recovery container for collecting the waste powder. The gas flow unit has a portion located between the receiving unit and the fixing unit of the recovery unit. as an image forming apparatus. The invention according to claim 2 The device comprises an image forming unit that forms a toner image on a recording material using a developer containing toner, a fixing unit that fixes the toner image formed in the image forming unit to the recording material, a recovery unit that recovers waste powder containing toner discharged from the image forming unit, and a gas circulation unit through which gas flows for cooling the area around the image forming unit or the fixing unit, and having a portion located between the recovery unit and the fixing unit, wherein the fixing unit has a heat source that generates heat outside the transport area where the recording material can be transported, and the gas circulation unit has a portion located between the recovery unit and the heat source of the fixing unit.It is an image forming apparatus. Claim 3 The invention is characterized in that the heat source of the fixing unit is a drive unit that drives a fixing member that heats or pressurizes the toner image to fix the toner image to the recording material, and the gas flow unit has a portion disposed between the recovery unit and the drive unit of the fixing unit. Claim 2 This is the image forming apparatus described in [reference]. Claim 4 The invention is characterized in that the gas flow section exhausts gas drawn in from a space located downstream of the fixing section in the direction of transport of the recording material to the outside of the main body of the device. Claim 1 or 2 This is the image forming apparatus described in [reference]. Claim 5 The invention is characterized in that the gas flow section comprises an intake section that draws in air from a space located downstream of the fixing section in the direction of transport of the recording material, an exhaust section that discharges the gas drawn in by the intake section to the outside of the main body of the device, and a flow section through which the gas flows from the intake section toward the exhaust section, wherein the flow section has a portion that is located between the recovery section and the fixing section. Claim 4 This is the image forming apparatus described in [reference]. Claim 6 The invention is characterized in that the exhaust section of the gas flow section discharges gas in a direction away from the recovery section. Claim 5 This is the image forming apparatus described in [reference]. Claim 7 The invention is characterized in that, in a cross-section perpendicular to the direction of gas flow in the portion of the gas flow section located between the recovery section and the fixing section, the length in the direction extending along the recovery section is longer than the length in the direction from the recovery section toward the fixing section. Claim 1 or 2 This is the image forming apparatus described in [reference]. [Effects of the Invention]

[0006] Claim 1 、2 According to this invention, compared to the case where there is no insulating member between the fixing part and the collection part, the adhesion of waste powder collected in the collection part can be suppressed. Claim 3According to this invention, compared to the case where the gas flow section does not have a portion located between the recovery section and the drive section, the adhesion of waste powder collected in the recovery section can be suppressed. Claims 4 and 5 According to this invention, the space between the fixing unit and the recovery unit can be insulated by using a gas circulation unit that circulates gas to cool the space located downstream of the fixing unit in the direction of transport of the recording material. Claim 6 According to this invention, compared to a case where the exhaust unit does not discharge gas away from the recovery unit, it is possible to suppress the temperature rise of the recovery unit caused by the gas discarded from the exhaust unit. Claim 7 According to this invention, compared to the case where the length of the gas flow section in the direction extending along the recovery section is shorter than the length in the direction from the recovery section to the fixing section, the adhesion of waste powder recovered in the recovery section can be suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing an image forming apparatus to which this embodiment is applied. [Figure 2] Figure 1 is an enlarged view of section II in the image forming apparatus shown. [Figure 3] This is a view of the top of the image forming apparatus, seen from the rear of the apparatus. [Figure 4] This is a schematic diagram illustrating the configuration of the cleaning device, and is a cross-sectional view of the cleaning device taken from a plane perpendicular to the depth direction of the image forming apparatus. [Figure 5] This is a view of the cleaning device from the V direction in Figure 4. [Figure 6] This diagram shows the fixing device, cleaning device, recovery device, and exhaust mechanism to which this embodiment is applied, viewed from the rear of the image forming apparatus. [Figure 7] Figure 6 shows the fixing device, cleaning device, recovery device, and exhaust mechanism viewed from direction VII. [Figure 8] Figure 7 shows the fixing device, cleaning device, recovery device, and exhaust mechanism viewed from direction VIII. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram showing an image forming apparatus 1 to which this embodiment is applied. FIG. 2 is an enlarged view of part II in the image forming apparatus 1 shown in FIG. 1. FIG. 3 is a view of the upper part of the image forming apparatus 1 as seen from the back side of the image forming apparatus 1. The image forming apparatus 1 shown in the figure is an image forming apparatus of an intermediate transfer type generally called a tandem type. This image forming apparatus 1 is provided with a plurality of image forming units 10Y, 10M, 10C, 10K in which toner images of respective color components are formed by an electrophotographic method. The image forming units 10Y, 10M, 10C, 10K form images of yellow (Y), magenta (M), cyan (C), and black (K) (hereinafter, these colors may sometimes be referred to as normal colors).

[0009] Further, the image forming apparatus 1 is provided with a primary transfer unit 10 that sequentially performs primary transfer of the toner images of respective color components formed by the respective image forming units 10Y, 10M, 10C, 10K onto the intermediate transfer belt 15. Furthermore, the image forming apparatus 1 is provided with a secondary transfer unit 20 that collectively performs secondary transfer of the superimposed toner image transferred onto the intermediate transfer belt 15 onto a sheet of paper P as an example of a recording material.

[0010] Each of the image forming units 10Y, 10M, 10C, 10K that function as an example of an image forming unit is provided with the following electrophotographic devices. First, a charger 12 that charges the photosensitive drum 11 is provided around the photosensitive drum 11 that rotates in the clockwise direction in the figure. Also, a laser exposure device 13 that writes an electrostatic latent image on the photosensitive drum 11 is provided. Note that the exposure beam by the laser exposure device 13 is indicated by reference numeral Bm in FIG. 1. In the following description, the photosensitive drums 11 provided in each of the image forming units 10Y, 10M, 10C, 10K may sometimes be referred to as photosensitive drums 11Y, 11M, 11C, 11K.

[0011] Furthermore, a developing device 14 is provided, which contains a developer including a carrier and toner, and visualizes the electrostatic latent image on the photoreceptor drum 11 using the toner. A primary transfer roll 16 is also provided, which transfers the toner images of each color formed on the photoreceptor drum 11 to an intermediate transfer belt 15 via a primary transfer unit 10. A drum cleaner 17 is also provided to remove any toner remaining on the photoreceptor drum 11. The drum cleaner 17 consists of, for example, a cleaning blade that contacts the surface of the photoreceptor drum 11 to scrape off waste powder containing toner remaining on the surface of the photoreceptor drum 11. In the following description, the drum cleaners 17 provided in the image forming units 10Y, 10M, 10C, and 10K may be referred to as drum cleaners 17Y, 17M, 17C, and 17K, respectively.

[0012] The intermediate transfer belt 15 moves in a predetermined counterclockwise direction as shown in Figure 1 by a drive roll 34 driven by a motor (not shown). The primary transfer section 10 includes primary transfer rolls 16 that are positioned opposite each other on either side of the intermediate transfer belt 15. Then, the toner images on each photoreceptor drum 11 are electrostatically attracted to the intermediate transfer belt 15 in sequence, and a superimposed toner image is formed on the intermediate transfer belt 15.

[0013] The secondary transfer unit 20 includes a secondary transfer roll 21, a belt member 22, and a support roll 23, which are positioned on the outer circumference (toner image holding surface side) of the intermediate transfer belt 15. The secondary transfer unit 20 also includes a backup roll 25, which are positioned on the inner circumference of the intermediate transfer belt 15. In the secondary transfer unit 20, the belt member 22 is wound around and supported on the outer circumference of the secondary transfer roll 21 and the support roll 23. In the secondary transfer unit 20, the outer circumference of the intermediate transfer belt 15 and the outer circumference of the belt member 22 are in contact. Furthermore, in the secondary transfer unit 20, the secondary transfer roll 21 is positioned to press against the backup roll 25, sandwiching the belt member 22 and the intermediate transfer belt 15. The secondary transfer roll 21 is then grounded, and a secondary transfer bias is formed between the secondary transfer roll 21 and the backup roll 25, and the toner image formed on the intermediate transfer belt 15 is secondary transferred onto the paper P conveyed to the secondary transfer unit 20.

[0014] Furthermore, the image forming apparatus 1 is provided with a fixing device 60, which is an example of a fixing unit for fixing the secondary transferred toner image onto the paper P. The fuser unit 60 comprises a fuser belt module 61 and a pressure roll 62 that is pressed against the fuser belt module 61. The fuser unit 60 is also positioned behind the fuser belt module 61 and the pressure roll 62 in the depth direction and includes a drive motor M (see Figure 6, described later) that drives the fuser belt module 61 and the pressure roll 62. In this fuser unit 60, the paper P is pressurized and heated at the position where the fuser belt module 61 and the pressure roll 62 come into contact (the fuser nip), thereby fixing the toner image to the paper P.

[0015] The anchoring belt module 61 comprises an endless anchoring belt 610 and support rolls 611 and 612 that are rotatably mounted and support the anchoring belt 610 from the inside. The support roll 611 receives a driving force from a drive source (not shown) and rotates clockwise in the figure. As the support roll 611 rotates, the anchoring belt 610 receives a driving force from the support roll 611 and moves in a clockwise direction in the figure. Furthermore, the fixing belt module 61 is equipped with a load-receiving member 615 that receives the load from the pressure roll 62 at a position opposite the pressure roll 62, with the fixing belt 610 in between. In the fixing device 60 of this embodiment, the paper P is sandwiched from both sides by the pressure roll 62 and the load-receiving member 615, and pressure is applied to the paper P. Furthermore, the anchoring belt module 61 is provided with heaters (not shown) inside the support rolls 611 and 612 and the load-receiving member 615 to heat them.

[0016] Furthermore, the image forming apparatus 1 is equipped with a transport unit 50 that transports the paper P, on which the toner image has been secondarily transferred in the secondary transfer unit 20, toward the fuser unit 60. The conveying unit 50 includes an endless conveying belt 51 and support rolls 52 and 53 that are rotatably mounted and support the conveying belt 51 from the inside. The support rolls 52 receive driving force from a drive source (not shown) and rotate clockwise in the figure. As the support rolls 52 rotate, the conveying belt 51 receives driving force from the support rolls 52 and moves in a clockwise direction in the figure.

[0017] Furthermore, the image forming apparatus 1 is equipped with a cleaning device 70 for cleaning the surface of the intermediate transfer belt 15. The cleaning device 70 cleans the waste powder containing toner remaining on the surface of the intermediate transfer belt 15. Furthermore, the image forming apparatus 1 is equipped with a recovery device 80 that recovers waste powder containing toner removed from the photoreceptor drum 11 by the drum cleaners 17Y, 17M, 17C, and 17K of each image forming unit 10Y, 10M, 10C, and 10K, and waste powder containing toner removed from the intermediate transfer belt 15 by the cleaning device 70. In this embodiment, a collection unit is configured to collect waste powder containing toner discharged from the image forming unit, comprising a cleaning device 70 and a collection device 80. The configurations of the cleaning device 70 and the collection device 80 will be described in detail later.

[0018] Furthermore, the image forming apparatus 1 is provided with a blower mechanism 100 through which heat discharged from the fixing device 60 and gas for cooling the paper P heated in the fixing device 60 circulate. The blower mechanism 100 in this embodiment includes a first duct 110 and a second duct 120 adjacent to each other in the direction of transport of the paper P in the fixing device 60. In the following description, the paper transport direction P in the fuser 60 may be simply referred to as the paper transport direction P or the transport direction.

[0019] Furthermore, the image forming apparatus 1 is provided with an exhaust mechanism 200, which is positioned adjacent to the fuser 60 on the downstream side in the paper transport direction, and which draws in air from around the fuser 60 and discharges it outside the image forming apparatus 1. The exhaust mechanism 200 is an example of a gas circulation section in which gas for cooling the area around the fuser 60 flows through a space formed inside. The configuration of the exhaust mechanism 200 will be explained in detail later.

[0020] Furthermore, the image forming apparatus 1 is provided with a pair of rotatable transport rolls 42 and 43, which transport the paper P discharged from the fixing device 60 further downstream, and a guide section 40 which guides the paper P being transported by the transport roll pair 41. Furthermore, the image forming apparatus 1 is provided with a paper discharge unit 35 that discharges the paper P that has passed through the guide unit 40 to the outside of the image forming apparatus 1.

[0021] Furthermore, the image forming apparatus 1 is provided with a paper transport path R1 that transports paper from the paper storage sections 31, 32, and 33 through the secondary transfer section 20, transport section 50, fixing device 60, transport roll pair 41, and guide section 40 toward the paper discharge section 35. In addition, the image forming apparatus 1 is provided with a paper reversal path R2 that reverses the front and back sides of the paper P after the image has been formed and passed through the transport roll pair 41, and transports this paper toward the secondary transfer section 20 again.

[0022] The basic image forming process of the image forming apparatus 1 will be described below. In the image forming apparatus 1, image data is output from an image reading device (not shown). This image data is then processed by an image processing device (not shown), converted into four-color color gradation data (Y, M, C, K), and output to the laser exposure unit 13.

[0023] In the laser exposure unit 13, according to the input colorant gradation data, an exposure beam Bm emitted from, for example, a semiconductor laser is irradiated onto each of the photoreceptor drums 11 of the image forming units 10Y, 10M, 10C, and 10K. After the surface of each photoreceptor drum 11 is charged by the charger 12, the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. Then, after a toner image is formed on the photoreceptor drum 11 by the developing unit 14, this toner image is transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where each photoreceptor drum 11 and the intermediate transfer belt 15 are in contact.

[0024] After the toner image is first transferred to the surface of the intermediate transfer belt 15, the toner image is transported to the secondary transfer section 20 by the movement of the intermediate transfer belt 15. In the secondary transfer section 20, the secondary transfer roll 21 is pressed against the backup roll 25 via the belt member 22 and the intermediate transfer belt 15. At this time, the paper P transported from the paper storage sections 31, 32, and 33 by the transport roll 36, etc., is sandwiched between the intermediate transfer belt 15 and the belt member 22.

[0025] Then, the unfixed toner image held on the intermediate transfer belt 15 is electrostatically transferred in one go onto the paper P in the secondary transfer unit 20. After that, the paper P on which the toner image has been electrostatically transferred is peeled off the intermediate transfer belt 15 and transported to the transport unit 50 located downstream of the secondary transfer unit 20 in the paper transport direction. The paper P transported to the transport unit 50 is then transported to the fixing device 60 by the transport belt 51. The toner image on the paper P, which has been transported to the fuser 60, is subjected to heat and pressure by the fuser 60 and fixed onto the paper P. The paper P on which the fixed image has been formed is then transported by the transport roll pair 41, passes through the guide section 40, and is discharged from the paper discharge section 35 to the outside of the image forming apparatus 1.

[0026] On the other hand, waste powder containing toner adhering to the photoreceptor drum 11 after primary transfer is removed by the drum cleaner 17. Similarly, waste powder containing toner adhering to the intermediate transfer belt 15 after secondary transfer is removed by the cleaning device 70. The waste powder removed by the drum cleaner 17 and the cleaning device 70 is then collected by the recovery device 80. In this way, the image forming process in the image forming apparatus 1 is repeatedly executed for the number of prints required.

[0027] Next, the cleaning device 70 of this embodiment will be described. Figure 4 is a schematic diagram illustrating the configuration of the cleaning device 70, and is a cross-sectional view of the cleaning device 70 cut by a plane perpendicular to the depth direction of the image forming apparatus 1 (see Figure 1). Figure 5 is a view of the cleaning device 70 from the V direction in Figure 4. The cleaning device 70 is equipped with a cleaning blade 71 that contacts the surface of the intermediate transfer belt 15 to scrape off any waste powder remaining on the surface of the intermediate transfer belt 15. The cleaning device 70 is also equipped with a cleaning brush 72 that rotates in contact with the surface of the intermediate transfer belt 15 upstream of the cleaning blade 71 in the direction of movement of the intermediate transfer belt 15. The cleaning brush 72 lifts the waste powder from the surface of the intermediate transfer belt 15, making it easier for the cleaning blade 71 to remove the waste powder. In the following explanation, the direction of movement of the intermediate transfer belt 15 may sometimes be simply referred to as the "direction of movement."

[0028] Furthermore, the cleaning device 70 is made of, for example, a thin sheet of metal, and is equipped with a sealing member 73 that contacts the intermediate transfer belt 15 downstream of the cleaning blade 71 in the direction of movement, and seals the inside of the cleaning device 70 from the outside of the cleaning device 70. The sealing member 73 also has the function of scraping off any waste powder on the intermediate transfer belt 15 that could not be completely removed by the cleaning blade 71.

[0029] Furthermore, the cleaning device 70 includes a housing 74 that houses the aforementioned components of the cleaning device 70 and through which waste powder is transported. The housing 74 is provided with a first transport path 741 and a second transport path 742, separated by a partition wall 74a. The first transport path 741 and the second transport path 742 are formed along the depth direction of the image forming apparatus 1. Furthermore, the housing 74 has a receiving section 74b provided opposite the front end of the second transport path 742, which receives the waste powder removed from the photoreceptor drum 11 of each image forming unit 10 by the drum cleaner 17. In addition, the housing 74 has a first discharge port 74c provided below the rear end of the first transport path 741, which discharges the waste powder transported along the first transport path 741 to a receiving section 811 of the recovery device 80, which will be described later. Furthermore, the housing 74 has a second discharge port 74d provided below the rear end of the second transport path 742, which discharges the waste powder transported along the second transport path 742 to a receiving section 811 of the recovery device 80.

[0030] Furthermore, the cleaning device 70 is provided in the first transport path 741 of the housing 74 and includes a first transport member 75 for transporting waste powder. The first transport member 75 is, for example, an auger provided along the depth direction and rotated by a drive source (not shown). The first transport member 75 transports the waste powder removed from the surface of the intermediate transfer belt 15 by the cleaning blade 71, etc., along the depth direction toward the first discharge port 74c. Furthermore, the cleaning device 70 is provided in the second transport path 742 of the housing 74 and includes a second transport member 76 for transporting waste powder. The second transport member 76 is, for example, an auger provided along the depth direction and rotated by a drive source (not shown). The second transport member 76 transports the waste powder, which has been removed from the photoreceptor drum 11 of each image forming unit 10 by the drum cleaner 17 and fed into the housing 74 from the receiving section 74b, along the depth direction toward the second discharge port 74d.

[0031] Next, the recovery device 80 of this embodiment will be described with reference to Figure 3 and other figures mentioned above. The recovery device 80 is located at the rear of the image forming apparatus 1 and transports the waste powder received from the cleaning device 70 to the recovery container 90 while stirring it. The recovery device 80 is located at the rear in the depth direction of the paper transport area where the paper P can be transported in the secondary transfer unit 20, the fixing device 60, etc. Furthermore, the recovery device 80 includes a recovery housing 81 through which the waste powder passes, and a stirring member 82 for stirring the waste powder passing through the recovery housing 81.

[0032] The recovery housing 81 has a cylindrical shape with a space formed inside through which waste powder passes, and is positioned along the direction of gravity. The positioning of the recovery housing 81 along the direction of gravity means that the direction of travel of the waste powder passing through the recovery housing 81 has a component corresponding to the direction of gravity. The recovery housing 81 is positioned above in the direction of gravity and has a receiving section 811 that receives waste powder discharged from the housing 74 of the cleaning device 70. The receiving section 811 of the recovery housing 81 receives waste powder discharged from the first discharge port 74c and the second discharge port 74d formed in the housing 84 of the cleaning device 70. In addition, the receiving section 811 receives waste powder that is discharged from the first discharge port 74c and the second discharge port 74d and falls in the direction of gravity.

[0033] The stirring member 82 is composed of, for example, an agitator extending along the axial direction of the recovery housing 81. The stirring member 82 moves back and forth within the recovery housing 81 by a drive source (not shown) to vibrate and break up the waste powder adhering to the inner wall of the recovery housing 81.

[0034] In the recovery device 80, the waste powder discharged from the cleaning device 70 and received in the receiving section 811 of the recovery housing 81 is agitated by the stirring member 82 within the space inside the recovery housing 81 and then transported to the recovery container 90 by gravity.

[0035] Next, the exhaust mechanism 200 of this embodiment will be described. Figure 6 shows the fixing device 60, cleaning device 70, recovery device 80, and exhaust mechanism 200 to which this embodiment is applied, viewed from the rear side of the image forming apparatus 1. Figure 7 shows the fixing device 60, cleaning device 70, recovery device 80, and exhaust mechanism 200 viewed from direction VII in Figure 6. Furthermore, Figure 8 shows the fixing device 60, cleaning device 70, recovery device 80, and exhaust mechanism 200 viewed from direction VIII in Figure 7.

[0036] The exhaust mechanism 200 draws in air from a space located downstream of the fuser 60 in the transport direction and discharges it to the outside of the image forming apparatus 1, thereby cooling the paper P discharged from the fuser 60 and the area around the fuser 60. The exhaust mechanism 200 includes an intake section 210 that draws in air from a space located downstream of the fixing device 60 in the transport direction. The exhaust mechanism 200 also includes a first flow section 220 that circulates the gas drawn in by the intake section 210 towards the back of the image forming apparatus 1, and a second flow section 230 that circulates the gas that has passed through the first flow section 220 further upstream in the transport direction. Furthermore, the exhaust mechanism 200 includes an exhaust port 240 that discharges the gas that has passed through the second flow section 230 to the outside of the image forming apparatus 1, and a fan 250 that generates a flow of gas from the intake section 210 through the first flow section 220 and the second flow section 230 to the exhaust port 240. Spaces through which gas flows are formed inside the intake section 210, the first flow section 220, and the second flow section 230 of the exhaust mechanism 200.

[0037] The air intake section 210 is located in the space downstream of the fixing device 60 in the transport direction, and is provided along the depth direction. More specifically, the air intake section 210 is provided along the depth direction above the transport roll pair 41 that transports the paper P discharged from the fixing device 60. Furthermore, the air intake section 210 faces the transport roll pair 41 with a gap in between. The intake section 210 has a rectangular parallelepiped shape that is elongated in the depth direction. Inside the intake section 210, a space T1 is formed through which gas flows from the front to the back in the depth direction.

[0038] Furthermore, the intake section 210 has an intake port 211 into which gas is drawn towards a space T1 formed inside the intake section 210. Although not shown in the figures, the intake section 210 has a plurality of intake ports 211 arranged side by side with gaps between them in the depth direction. Each intake port 211 also opens downward in the direction of gravity toward the conveying roll pair 41.

[0039] The first circulation section 220 is provided along the depth direction from the rear end of the intake section 210. The first circulation section 220 is provided further back in the depth direction than the paper transport area in which the paper P is transported in the fuser 60 and the transport roll pair 41. As will be described in detail later, in the exhaust mechanism 200 of this embodiment, a part of the first circulation section 220 is located between the recovery device 80 and the fuser 60. Furthermore, the first circulation section 220 has a flat, box-like shape that extends along the depth direction and the direction of gravity. Inside the first circulation section 220, a space T2 is formed that is continuous with the space T1 of the intake section 210 on the back side in the depth direction.

[0040] The second flow section 230 is provided along the conveying direction from the rear end of the first flow section 220. More specifically, the second flow section 230 extends upstream in the conveying direction from the rear end of the first flow section 220. The second flow section 230 is provided further back in the depth direction than the fixing motor M of the fixing device 60. The second distribution section 230 has a rectangular parallelepiped shape overall. Inside the second distribution section 230, a space T3 is formed that is continuous with the space T2 of the first distribution section 220 on the upstream side in the conveying direction.

[0041] The exhaust port 240 is located on the upstream side in the transport direction of the second flow section 230. More specifically, the exhaust port 240 is located on the rear side of the second flow section 230 and opens towards the rear in the depth direction toward the outside of the image forming apparatus 1. The fan 250 is located inside the second circulation section 230 and rotates by a drive source (not shown), generating a gas flow from the intake section 210 through the first circulation section 220 and the second circulation section 230 to the exhaust port 240.

[0042] Next, we will explain the operation of the exhaust mechanism 200. When the exhaust mechanism 200 is used to cool the area around the fixing device 60, the fan 250 is driven and rotated by a drive source (not shown). As a result, the gas drawn in from the intake section 210 flows through the space T1 of the intake section 210, the space T2 of the first flow section 220, and the space T3 of the second flow section 230, cooling the area around the fixing device 60.

[0043] More specifically, gas is drawn into the space T1 inside the intake section 210 through the intake port 211 of the intake section 210 from the space located downstream of the fixing device 60 in the transport direction, or more specifically, from the space around the transport roll pair 41 on which the paper P discharged from the fixing device 60 is transported. The gas that enters the space T1 of the intake section 210 then flows through space T1 from the front to the back in the depth direction. The gas that reaches the back end of the intake section 210 then enters the space T2 of the first circulation section 220.

[0044] The gas that enters space T2 in the first circulation section 220 circulates through space T2 from the front to the back in the depth direction. The gas that reaches the back end of the first circulation section 220 then enters space T3 in the second circulation section 230. The gas that enters the space T3 of the second flow section 230 flows through the space T3 from the downstream side to the upstream side in the conveying direction. The gas that reaches the upstream end in the conveying direction of the second flow section 230 is then discharged to the outside of the image forming apparatus 1 through the exhaust port 240. Thus, according to the exhaust mechanism 200 of this embodiment, the high-temperature gas present around the fixing device 60 is discharged to the outside of the image forming apparatus 1 via the intake section 210, the first flow section 220, the second flow section 230, and the exhaust port 240, thereby cooling the fixing device 60 and its surroundings. In addition, the high-temperature paper P discharged from the fixing device 60 and conveyed by the transport roll pair 41 is cooled.

[0045] Next, the relationship between the exhaust mechanism 200, the recovery device 80, and the fixing device 60 of this embodiment will be described. The exhaust mechanism 200 of this embodiment has a portion that is positioned between the recovery device 80 and the fixing device 60. More specifically, as shown in Figures 6 and 8, the first flow section 220 of the exhaust mechanism 200 is positioned between the recovery housing 81 of the recovery device 80 and the fixing motor M of the fixing device 60. In this description of the embodiment, "A has a portion located between B and C" means that there are points in B and C such that A lies on a line connecting a point selected from B and a point selected from C.

[0046] In this case, if the recovery housing 81 of the recovery device 80 is directly facing the fixing device 60, the heat generated in the fixing device 60 may cause the waste powder being transported inside the recovery housing 81 to melt and solidify inside the recovery housing 81. In contrast, in this embodiment, the exhaust mechanism 200 has a portion positioned between the recovery device 80 and the fixing device 60, so that the heat generated from the fixing device 60 is blocked and insulated by the exhaust mechanism 200. As a result, in this embodiment, compared to the case where there is no insulating member between the recovery device 80 and the fixing device 60, heat is less likely to be transferred from the fixing device 60 to the recovery device 80, and the adhesion of waste powder conveyed inside the recovery housing 81 is suppressed.

[0047] Furthermore, a space T2 through which gas flows is formed inside the first flow section 220 of the exhaust mechanism 200. By adopting this configuration, in this embodiment, an insulating layer is formed between the recovery device 80 and the fixing device 60 by the air present in space T2. As a result, compared to the case where the space between the recovery device 80 and the fixing device 60 is insulated with, for example, a metal plate, heat is less likely to be transferred from the fixing device 60 to the recovery device 80, and the adhesion of the waste powder being transported inside the recovery housing 81 is further suppressed.

[0048] Furthermore, in this embodiment, the first flow section 220 of the exhaust mechanism 200 is positioned between the recovery housing 81 of the recovery device 80 and the drive motor M, which is the heat source for the fuser device 60. In particular, the drive motor M is a drive source that drives the fuser belt module 61 and the pressure roll 62, which are examples of fuser members that heat or pressurize the paper P on which the toner image is formed, and is therefore prone to becoming hot. In this embodiment, by having a portion of the exhaust mechanism 200 positioned between the recovery device 80 and the drive motor M of the fuser device 60, heat is less likely to be transferred from the fuser device 60 to the recovery device 80 compared to, for example, the case where the exhaust mechanism 200 is positioned between the recovery device 80 and the parts of the fuser device 60 other than the drive motor M, and the adhesion of waste powder conveyed inside the recovery housing 81 is further suppressed.

[0049] Furthermore, in the recovery device 80 of this embodiment, the waste powder received from the cleaning device 70 is dropped by gravity within the recovery housing 81 and transported to the recovery container 90. With this configuration, compared to, for example, transporting the waste powder using a transport member such as a transport auger within the recovery housing 81, clogging of the waste powder and poor transport are more likely to occur within the recovery housing 81 if the waste powder becomes solidified. In this embodiment, as described above, the exhaust mechanism 200 makes it difficult for heat to be transferred from the fixing device 60 to the recovery device 80, thereby making it easier to suppress clogging and poor transport of waste powder within the recovery housing 81.

[0050] Furthermore, in this embodiment, it is preferable that the exhaust mechanism 200 has a portion that is positioned between the receiving portion 811 in the recovery housing 81 of the recovery device 80 and the fixing device 60. In this example, the first flow portion 220 of the exhaust mechanism 200 is positioned between the receiving portion 811 in the recovery housing 81 of the recovery device 80 and the fixing motor M of the fixing device 60. As described above, the receiving section 811 receives the waste powder that has been transported along the depth direction of the image forming apparatus 1 via the first transport path 741 and the second transport path 742 of the cleaning device 70, and then falls in the direction of gravity from the first discharge port 74c and the second discharge port 74d. In addition, the receiving section 811 is the part where the transport direction of the waste powder changes from the depth direction to the direction of gravity. For this reason, if the waste powder adheres to the receiving section 811, the waste powder is likely to accumulate, causing clogging and transport problems. In this embodiment, the exhaust mechanism 200 has a portion positioned between the receiving section 811 and the fixing device 60, which makes it difficult for heat to be transferred from the fixing device 60 to the receiving section 811, thereby suppressing the adhesion of waste powder in the receiving section 811. This makes it easier to suppress clogging and poor transport of waste powder in the receiving section 811.

[0051] Furthermore, in the exhaust mechanism 200 of this embodiment, the gas drawn in from the space located downstream of the fixing device 60 in the transport direction is discharged through the exhaust port 240 toward the back in the depth direction toward the outside of the image forming apparatus 1. In other words, the exhaust mechanism 200 of this embodiment draws in the gas drawn in from the space located downstream of the fixing device 60 in the transport direction and discharges through the exhaust port 240 toward away from the recovery device 80. By adopting this configuration, in this embodiment, the temperature rise of the recovery device 80 due to the high-temperature gas discharged from the exhaust port 240 is suppressed, and the adhesion of waste powder in the recovery device 80 is further suppressed.

[0052] Furthermore, in the exhaust mechanism 200 of this embodiment, as described above, the first flow section 220, which is positioned between the recovery device 80 and the fixing device 60, has a flattened shape in the direction of gravity. More specifically, in a cross section perpendicular to the depth direction, which is the direction of gas travel in the first flow section 220 (indicated by reference numeral 220A in Figure 6), the length in the direction of gravity, which is one example of a direction extending along the recovery device 80, is longer than the length in the transport direction, which is one example of a direction from the recovery device 80 toward the fixing device 60. By adopting this configuration, the area insulated by the first distribution section 220 from the recovery device 80 and the fixing device 60 can be enlarged, making it more difficult for heat to be transferred from the fixing device 60 to the recovery device 80. As a result, the adhesion of waste powder in the recovery device 80 is further suppressed.

[0053] The conveying direction of the waste powder in the recovery device 80 and the direction of gas travel in the exhaust mechanism 200 described above are merely examples for illustrative purposes and are not limited to those described above. For example, as long as the relative positional relationship of the fixing device 60, the recovery device 80 and the exhaust mechanism 200 satisfies the above-described relationship, the conveying direction of the waste powder by the recovery housing 81 of the recovery device 80 does not have to be in the direction of gravity, and the direction of gas travel in the first flow section 220 of the exhaust mechanism 200 does not have to be in the depth direction.

[0054] Although embodiments of the present invention have been described above, the configurations described above are not limited to the embodiments and their modifications, and can be modified without departing from the spirit of the invention. In other words, it is understood that various changes in form and details are possible without departing from the spirit and scope of the claims. For example, some of the components described above may be omitted, or other functions may be added to each component described above. [Explanation of Symbols]

[0055] 1…Image forming apparatus, 50…Conveying unit, 51…Conveying belt, 60…Fixing device, 61…Fixing belt module, 62…Pressure roll, 70…Cleaning device, 80…Recovery device, 81…Recovery housing, 82…Agitation member, 100…Blowing mechanism, 110…First duct, 120…Second duct, 200…Exhaust mechanism, 210…Intake unit, 220…First flow unit, 230…Second flow unit, 240…Exhaust port, 250…Fan

Claims

1. An image forming unit comprising an image holder that holds a toner image and moves in a circular motion, wherein a toner image is formed on a recording material using a developer containing toner, A fixing unit that fixes the toner image formed in the image forming unit onto a recording material, A cleaning unit for cleaning the waste powder from the image holder of the image forming unit. A collection unit that receives and collects waste powder containing toner discharged from the image forming unit from the cleaning unit, The system includes a gas flow section through which gas flows for cooling the area around the image forming section or the fixing section, and a gas flow section having a portion located between the recovery section and the fixing section. The collection unit includes a receiving unit that receives waste powder from the cleaning unit, and the waste powder received from the cleaning unit is dropped into a collection container for collecting the waste powder and transported thereto. The gas flow section has a portion that is located between the receiving section and the fixing section of the recovery section. Image forming apparatus.

2. An image forming unit that forms a toner image on a recording material using a developer containing toner, A fixing unit that fixes the toner image formed in the image forming unit onto a recording material, A recovery unit for collecting waste powder containing toner discharged from the image forming unit, A gas flow section through which gas flows for cooling the area around the image forming section or the fixing section, and which has a portion located between the recovery section and the fixing section. Equipped with, The fixing unit has a heat source that generates heat outside the transport area where the recording material can be transported. The gas flow section has a portion that is positioned between the recovery section and the heat source of the fixing section. Image forming apparatus.

3. The heat source of the fixing unit is a drive unit that drives a fixing member that heats or pressurizes the toner image to fix the toner image to the recording material. The image forming apparatus according to claim 2, characterized in that the gas flow section has a portion disposed between the recovery section and the drive section of the fixing section.

4. The image forming apparatus according to claim 1 or 2, characterized in that the gas flow section exhausts gas drawn in from a space located downstream of the fixing section in the direction of transport of the recording material to the outside of the apparatus body.

5. The image forming apparatus according to claim 4, wherein the gas flow section comprises an intake section that draws in air from a space located downstream of the fixing section in the direction of transport of the recording material, an exhaust section that discharges the gas drawn in by the intake section to the outside of the main body of the apparatus, and a flow section through which the gas flows from the intake section toward the exhaust section, and the flow section has a portion that is located between the recovery section and the fixing section.

6. The image forming apparatus according to claim 5, characterized in that the exhaust section of the gas flow section discharges gas in a direction away from the recovery section.

7. The image forming apparatus according to claim 1 or 2, characterized in that, in a cross-section perpendicular to the direction of gas flow in the portion of the gas flow section located between the recovery section and the fixing section, the length in the direction extending along the recovery section is longer than the length in the direction from the recovery section toward the fixing section.

Images