JP2005106964A - Image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the effect of cooling inside a process cartridge and to miniaturize a printer. <P>SOLUTION: In the printer 10, a blower fan 43 is disposed facing the peripheral face of a photoreceptor drum 28. With the blower fan 43, air is sent into the process cartridge 14 from one end of the exposure window of the process cartridge 14, the air is caused to flow from the axial one end of the photoreceptor drum 28 to the other end, and the air is taken out from the other end of the exposure window. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium, and a process cartridge that houses at least a photoreceptor.

  In an image forming apparatus employing an electrophotographic system such as a printer or a copying machine, if the temperature inside one or a plurality of process cartridges containing a photosensitive drum, a charger, and a developer exceeds a certain temperature, the toner Will solidify. This causes a problem that the toner cannot be favorably moved from the developing roll to the photosensitive drum or from the photosensitive drum to the recording medium, and a good toner image cannot be obtained. For this reason, conventionally, a method for suppressing the temperature rise inside the process cartridge has been devised (see, for example, Patent Documents 1 to 3).

  Patent Document 1 discloses a configuration in which air is sent into a process cartridge from an exposure window through which information light for forming a latent image is incident on a photosensitive drum to cool the inside of the process cartridge. In this configuration, air is taken into the process cartridge from the entire exposure window, and the photosensitive drum is cooled by applying air to the entire axial direction of the photosensitive drum.

  However, since it has been difficult to make the air volume applied to the photosensitive drum uniform from one end to the other end in the axial direction of the photosensitive drum, there is a problem that uneven cooling occurs on the photosensitive drum. It was. Further, in order to apply air to the entire photosensitive drum, in order to widen the width of the air flow path, the fan must be enlarged, and there is a problem that the apparatus is enlarged.

  In Patent Documents 2 and 3, air is sent from the end surface side of the photosensitive drum into the process cartridge, and the photosensitive drum is cooled by flowing air from one end portion to the other end portion in the axial direction of the photosensitive drum. It is disclosed. In this configuration, air uniformly strikes from one end portion to the other end portion in the axial direction, so that cooling unevenness hardly occurs on the photosensitive drum. Further, the fan can be downsized by reducing the width of the air flow path.

However, since the fan and the air duct had to be arranged on the side of the process cartridge, there was a problem that the width of the apparatus widened in the axial direction of the photosensitive drum and the apparatus became large.
Japanese Patent Publication No. 5-39479 Japanese Patent Laid-Open No. 2002-258697 JP-A-5-241411

  The present invention has been made in consideration of the above facts, and forms an air flow path through which air flows from one end portion to the other end portion in the axial direction of the photoconductor, and the width of the image forming apparatus is in the axial direction of the photoconductor. The purpose is to prevent the image forming apparatus from being enlarged.

  The image forming apparatus according to claim 1, wherein at least a photoconductor for transferring a developer is accommodated on a recording medium, and an exposure window is formed on the photoconductor for allowing information light for forming a latent image to enter the photoconductor. It has a process cartridge, and an air blowing means for sending air into the process cartridge from one end of the exposure window and flowing air from one end to the other end in the axial direction of the photosensitive member.

  In the image forming apparatus according to the first aspect, the developer is transferred onto the recording medium by the photosensitive member. An exposure window for allowing information light for forming a latent image on the photosensitive member to enter the photosensitive member is formed in the process cartridge that houses at least the photosensitive member.

  The blowing unit sends air from one end of the exposure window into the process cartridge, and flows air from one end of the photosensitive member in the axial direction to the other end. Accordingly, air can be uniformly applied from one end portion to the other end portion in the axial direction of the photoconductor, so that cooling unevenness hardly occurs on the photoconductor.

  Further, since the air blowing means can be disposed in front of the exposure window, that is, facing the peripheral surface of the photosensitive drum, it is not necessary to provide a space for installing the air blowing means on the side of the process cartridge, and the width of the image forming apparatus is photosensitive. It can suppress spreading in the axial direction of the body. Therefore, the image forming apparatus can be downsized.

  Furthermore, since the width of the air flow path can be reduced as required, for example, the cooling effect can be increased only by increasing the rotational speed of the fan. Therefore, the cooling effect can be increased without increasing the size of the blower.

  The image forming apparatus according to claim 2 is the image forming apparatus according to claim 1, wherein the air blower includes air that enters from one end of the exposure window through the other end of the exposure window. It is characterized by forming a circulating flow.

  In the image forming apparatus according to the second aspect, an air circulation flow is formed by the air blowing means so that the air exiting from the other end of the exposure window enters the one end of the exposure window. As a result, air does not stay in the process cartridge, so that the photoreceptor and the process cartridge can be efficiently cooled.

  An image forming apparatus according to a third aspect is the image forming apparatus according to the second aspect, wherein an air supply path through which air of the air circulation flow and outside air flow, an exhaust path, the exhaust path, and the exposure are provided. And a branch passage for branching air to the window.

  In the image forming apparatus according to the third aspect, the air in the air circulation flow and the outside air flow into the air supply path. The mixed air is branched into the exhaust path and the exposure window by the branch path. For this reason, the air heated in the process cartridge is cooled by the outside air and discharged from the exhaust path. Thereby, the temperature rise of the air of the air circulation flow can be prevented.

  An image forming apparatus according to a fourth aspect is the image forming apparatus according to the second or third aspect, further comprising a cooling member that cools the air in the air circulation flow.

  In the image forming apparatus according to the fourth aspect, the air in the air circulation flow heated in the process cartridge is cooled by a cooling member such as a Peltier element. Thereby, the cooling effect in the process cartridge can be enhanced.

  An image forming apparatus according to claim 5 is the image forming apparatus according to claim 3 or 4, further comprising an ozone filter that is provided in the exhaust path and collects ozone generated in the process cartridge. It is characterized by that.

  In the image forming apparatus according to the fifth aspect, ozone generated in the process cartridge is caused to flow into the exhaust path by the air taken out from the other end of the exposure window, and is collected by an ozone filter provided in the exhaust path. As a result, ozone is not released into the atmosphere and does not cause environmental destruction.

  The process cartridge according to claim 6 contains at least a photosensitive member for transferring a developer to a recording medium, and an exposure window for allowing information light for forming a latent image to enter the photosensitive member on the photosensitive drum. A process cartridge, characterized by having a guide duct that is provided at least at one end of the exposure window and guides air from the one end into the process cartridge.

  In the process cartridge according to the sixth aspect, a guide duct is provided at least at one end of the exposure window, and air is guided into the process cartridge from one end of the exposure window by the guide duct. As a result, the air sent into the process cartridge flows from one end portion in the axial direction of the photosensitive member to the other end portion, and the entire axial direction of the photosensitive member is uniformly cooled.

  Since the present invention is configured as described above, it is possible to form an air flow path through which air flows from one end portion to the other end portion in the axial direction of the photoconductor, and to suppress the width of the image forming apparatus from expanding in the axial direction of the photoconductor. The image forming apparatus can be downsized.

  The first embodiment will be described below with reference to the drawings.

  As shown in FIG. 1, a printer 10 as an image forming apparatus includes a printer main body 12, a process cartridge 14 that can be attached to and detached from the printer main body 12, and a two-stage paper feed cassette that is disposed below the printer main body 12. 16.

  A nudger roll 18 is disposed at the back end of the paper feed cassette 16, and a retard roll 20 and a feed roll 22 that forms a roller pair with the retard roll 20 are disposed on the downstream side of the nudger roll 18 in the conveying direction.

  In addition, a resist roll 24 is disposed on the downstream side of the retard roll 20 and the feed roll 22 in the conveying direction, and a transfer roll 26 and a photosensitive drum 28 are disposed on the downstream side of the resist roll 24. The photosensitive drum 28 is accommodated in the process cartridge 14 and is in contact with the transfer roll 26. A fixing roll 30 is disposed on the downstream side in the transport direction of the transfer roll 26 and the photosensitive drum 28, and a discharge roll 32 is disposed on the downstream side in the transport direction of the fixing roll 30.

  The recording medium stored in the paper feed cassette 16 is sent out from the paper feed cassette 16 by the nudger roll 18. The recording medium is nipped and conveyed by the retard roll 20 and the feed roll 22 and temporarily stopped by the registration roll 24. Then, the recording medium is fed by the registration roll 24 between the transfer roller 26 and the photosensitive drum 28 at a timing, and the toner image is transferred from the photosensitive drum 28. The toner image is fixed on the recording medium by the transfer roll 30 and discharged from the printer main body 12 by the discharge roll 32.

  In the printer main body 12, a scanning type laser exposure device 34 is disposed on the side of the process cartridge 14. The laser emitting surface 34A of the laser exposure device 34 is directed to the photosensitive drum 28, and the exposure window for allowing the laser beam to enter the photosensitive drum 28 facing the laser emitting surface 34A of the cartridge 36 of the process cartridge 14. 38 is formed.

  In the printer main body 12, a blower 40 for sending air from the exposure window 38 into the cartridge 36 is disposed above the laser exposure device 34. The blower 40 will be described later.

  As shown in FIG. 2, the process cartridge 14 includes a photosensitive unit 48 in which a photosensitive drum 28, a charging roll 42, and a cleaning blade 46 are disposed, and a developing unit 50 in which a developing roll 44 is disposed. Yes.

  As shown in FIG. 3, the photoconductor unit 48 and the developing unit 50 are rotatably connected by coupling pins 59A and 59B. The photosensitive unit 48 and the developing unit 50 are urged by the tension coil spring 52 and the compression coil spring 54 in the direction in which the photosensitive drum 28 and the developing roll 56 approach each other, and the photosensitive drum 28 and the developing roll 56 are pressed against each other. It has been.

  Further, a memory 58 for storing the number of printed sheets is provided on the side surface of the photoconductor unit 48.

  As shown in FIG. 4, in the photoreceptor unit 48, the photoreceptor drum 28 and the charging roll 42 are rotatably supported by the unit housing 64 by the photoreceptor drum bearings 60A and 60B and the charging roll bearings 62A and 62B. Yes. One of the charging roll bearings 62A and 62B also serves as a power feeding portion.

  Two fingers 66A and 66B are rotatably supported by the unit housing 64. The tips of the fingers 66A and 66B are pressed against the photosensitive drum 28 by finger springs (not shown), and the recording medium to be wound around the photosensitive drum 28 is peeled off from the photosensitive drum 28.

  As shown in FIG. 2, a cleaning blade 46 is in contact with the top of the photosensitive drum 28, and a toner collection space 70 is formed above the cleaning blade 46 in the unit housing 64. . The cleaning blade 46 scrapes off the toner from the photosensitive drum 28 and collects it in the toner recovery space 70.

  A paddle 72 is rotatably provided in the toner collection space 70. The paddle 72 is supported on the unit housing 64 by a paddle gear 74 (see FIG. 4), and conveys the toner collected in the toner collection space 70 by rotating to the back side of the toner collection space 70.

  A part of the photosensitive drum 28 is exposed from the unit housing 64, and a shutter 76 that opens and closes the photosensitive drum 28 is provided above the unit housing 64. The shutter 76 is supported on the unit housing 64 by a shutter shaft 78 (see FIG. 4) so as to be opened and closed. Before the process cartridge 14 is mounted on the printer main body 12, the exposed portion of the photosensitive drum 28 is closed. When the process cartridge 14 is mounted on the printer main body 12, the exposed portion of the photosensitive drum 28 is opened.

  As shown in FIG. 5, the developing unit 50 includes a unit housing 80 in which a front housing 80F and a rear housing 80R are joined. As shown in FIG. 2, the inside of the unit housing 80 is divided into a toner storage space 82 and a developing portion 84 in which the developing roll 44 is disposed. The toner storage space 82 is divided by a partition wall 86 into a first toner storage space 82A above the scanning line optical path BL and a second toner storage space 82B below the scanning line optical path BL.

  As shown in FIG. 6, the partition wall 86 extends in the axial direction of the photosensitive drum 28, and forms an exposure window 38 that forms a scanning line optical path BL from the laser exposure device 34. The partition wall 86 forms toner passages 88A and 88B together with the unit housing 80 on both the left and right sides of the exposure window 38. The toner passages 88A and 88B connect the first toner storage space 82A and the second toner storage space 82B.

  A first stirring member 90 is rotatably provided in the first toner storage space 82A. The first stirring member 90 includes a shaft portion 92 and winding portions 94A and 94B formed in a spiral shape from the central portion of the shaft portion 92 toward both end portions. Winding portion 94A and winding portion 94B extend in different winding directions. When the first stirring member 90 rotates, the toner stored in the first toner storage space 82A is supplied to the second toner storage space 82B through the toner passages 88A and 88B.

  A second stirring member 96 is rotatably provided in the second toner storage space 82B. The second stirring member 96 is a screw shaft that includes a shaft portion 98 and screw portions 99A and 99B that rotate in different winding directions from the central portion of the shaft portion 98 toward both ends. When the second stirring member 96 rotates, the toner supplied to both end portions of the second toner storage space 82B is collected in the central portion. Then, as shown in FIG. 2, it is supplied to the third stirring member 102.

  The third stirring member 102 and the fourth stirring member 104 are provided in the second toner storage space 82B. The third stirring member 102 includes a shaft portion 106 and a plate portion 108 having one end fixed to the shaft portion 106 and extending in the circumferential direction of the shaft portion 106, and the toner is supplied to the fourth stirring member 104. Supply.

  The fourth stirring member 104 is provided at the outlet of the second toner storage space 82B, and supplies the toner supplied by the third stirring member 102 to the developing roll 44. Mix the scraped toner.

  As shown in FIG. 5, the developing roll 44 is formed by winding a sleeve around a magnet roll, and tracking caps 110A and 110B are attached to both ends. The tracking caps 110A and 110B come into contact with the photosensitive drum 28, and the developing roll 44 is pressed against the photosensitive drum 28 by the tension coil spring 52 and the compression coil spring 54 to secure a developing gap.

  As shown in FIG. 2, the developing roll 44 is in contact with a layer thickness regulating member 112 that is a plate formed of resin. The layer thickness regulating member 112 regulates the layer thickness of the toner attached to the developing roll 44. Further, as shown in FIG. 5, the side surface of the developing roll 44 is sealed with a sealing material 114.

  The toner caps 116A and 116B are detachably attached to the unit housing 80, and when the toner caps 116A and 116B are removed from the unit housing 80, the first toner storage space 82A or the second toner storage space 82B. Toner is supplied.

  The drive system in the process cartridge 14 is transmitted with a driving force from the photosensitive drum 28 side, and the developing roll 44 and the first to fourth agitators through the developing roll gear 118, the agitating member gear 120, and the idle gear 122. Transmitted to members 90, 96, 102, 104. A seal member 126 is inserted into the bearing portion of the stirring member gear 120. Further, the stirring member gear 120 and the idle gear 122 are surrounded by a gear cover 124.

  Next, the operation of the configuration described so far will be described.

  The photosensitive drum 28 is uniformly charged by the charging roll 42. The charged photosensitive drum 28 is irradiated with a laser beam emitted from the laser exposure device 34 based on the image signal, and a latent image is formed at the latent image writing position P. The laser beam from the laser exposure device 34 enters the process cartridge from the exposure window 38 of the process cartridge 14. The latent image formed on the photosensitive drum 28 by the laser exposure device 34 is visualized by the developing roll 44.

  Then, as described above, the toner is transferred from the photosensitive drum 28 to the recording medium fed from the paper feeding cassette 16 between the photosensitive drum 28 and the transfer roll 26. The recording medium is fixed with the toner image when passing through the fixing roll 30, and is discharged from the printer main body 12.

  Here, the toner is solidified when the temperature exceeds a predetermined temperature, and the toner is not transported well in the process cartridge 14, and a good toner image cannot be formed on the recording medium. For this reason, air is sent into the process cartridge 14 by the blower 40 to prevent the temperature inside the process cartridge 14 from rising. Hereinafter, the blower 40 will be described.

  As shown in FIG. 7, the blower 40 faces the peripheral surface of a roll-shaped process member housed in the process cartridge 14 such as the photosensitive drum 28 and the developing roll 44 (perpendicular to the axial direction of the process member). The projection area S in the direction (see FIG. 8) is arranged. The air blower 40 faces the peripheral surface of the process member and extends in the axial direction of the process member, and the central portion in the direction in which the air duct 41 extends, that is, the central portion in the axial direction of the process member. It is comprised with the ventilation fan 43 arrange | positioned facing. The intake duct 41 </ b> A of the air duct 41 is closed on the top and bottom of the blower fan 43 and on the process cartridge 14 side (right side in the drawing), and the right and front sides of the blower fan 43 are open. When the blower fan 43 rotates, as shown by an arrow A in FIGS. 7 and 8, outside air is supplied through the four vent holes 45A formed in the printer housing 45 and the opening of the intake side duct 41A. It flows to the side duct 41B. That is, as shown in FIG. 8, a first air passage L1 that flows along the axial direction of the photosensitive drum 28 is formed.

  As shown in FIG. 9, the air supply side duct 41 </ b> B is closed at the upper part and the left and right sides of the blower fan 43, and the lower part of the blower fan 43 is opened. As described above, since the air blower 40 is disposed above the laser exposure device 34, air flows from the opened lower portion of the air supply side duct 41B to the laser exposure device 34 as indicated by an arrow C in the figure. As a result, the laser exposure device 34, which is a heat source, is cooled.

  Further, a branch duct 47 that is a branch path L3 that branches part of the air flowing through the air supply side duct 41B to the process cartridge 14 side is provided on the wall surface of the air supply side duct 41B on the process cartridge 14 side. The opening 47A of the branch duct 47 faces one end of the exposure window 38. A guide duct 49 protrudes obliquely downward from the lower part of the exposure window 38. Therefore, as indicated by an arrow B in FIG. 8, the air flowing through the branch duct 47 is guided from one end of the exposure window 38 into the process cartridge 14 by the guide duct 49. Then, the air that has flowed into the process cartridge 14 flows from one end of the photosensitive drum 28 in the axial direction to the other end, and returns to the blower fan 43 from the other end of the exposure window 38. Since the air circulation path L2 (see FIG. 8) through which air flows from one end portion to the other end portion in the axial direction of the photosensitive drum 28 is thus formed, the shafts of the photosensitive drum 28, the charging roll 42, and the developing roll 44 are formed. Air uniformly contacts the entire direction, and cooling unevenness does not occur. Further, since the width of the air flow path in the process cartridge 14 is narrowed, the cooling effect in the process cartridge 14 can be increased only by increasing the rotational speed of the blower fan 43. Therefore, it is not necessary to increase the size of the blower fan 43, and the printer body 12 can be reduced in size.

  As described above, outside air flows into the intake side duct 41B. That is, as shown in FIG. 8, an air supply path L4 is formed through which the outside air and the air recirculated by the air circulation path L2 flow into the first air path L1. For this reason, the air heated in the process cartridge 14 merges with the outside air and is cooled and circulates through the air circulation path L2 or flows through the first air path L1.

  Further, in the air supply side duct 41B, a part of the air is guided to the branch duct 47 and circulates through the air circulation path L2, but the remaining air goes straight, and as shown in FIG. The air is exhausted from the vent holes 51A and 45B. That is, as shown in FIG. 8, an exhaust path L5 for discharging air from the air circulation path L1 is connected to the air path L1. For this reason, a part of the air heated in the process cartridge 14 is discharged from the exhaust path L5, so that the temperature rise of the circulating air is suppressed.

  Further, as shown in FIG. 10, the power supply unit 55 is attached to the frame 51 so as to face the vent hole 51 </ b> A. That is, the power supply unit 55 is disposed in the exhaust path L5. The power supply board 55A of the power supply unit 55 has a vent hole 55B. For this reason, air flows from the back surface to the front surface of the power supply board 55A, and the electronic components provided on the front surface are cooled.

  Further, as shown in FIG. 9, a guide duct 57 is provided at the end of the upper surface of the air supply duct 41A. As shown in FIG. 10, the guide duct 57 extends to the outside of the frame 51. The upper end portion 51B of the frame 51 is bent outward at a substantially right angle, and closes the lower portion of the opened guide duct 57. A vent hole 51 </ b> C is formed in the upper end portion 51 </ b> B, and the air guided by the guide duct 57 flows between the printer casing 53 and the frame 51. For this reason, the electronic component 61 provided on the surface of the power supply board 55A is cooled.

  Further, an ozone filter 63 is attached to the printer housing 45 so as to face the vent hole 45B. For this reason, the ozone that has been extracted from the process cartridge 14 and has flowed to the exhaust path L3 in the air that has flowed to the exhaust path L3 is recovered by the ozone filter 63. Thus, ozone is not discharged from the printer 10 and does not cause environmental destruction.

  As described above, air is sent from one end of the exposure window 38 into the process cartridge 14 by the blower 40 and air is taken out from the other end of the exposure window 38. It can arrange | position without protruding from the both ends of an axial direction. As a result, the printer body 12 can be prevented from spreading in the axial direction of the process member, and the printer body 12 can be downsized.

  Next, a modified example of the blower 40 will be described. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted.

  As shown in FIG. 11, the branch duct 101 is connected to the air supply side duct 41 </ b> B of the air duct 41 of the blower 100. The branch duct 101 extends to the printer casing 45, and the printer casing 45 has a vent hole 45 </ b> C facing the branch duct 101.

  The branch duct 101 and the air supply side duct 41 </ b> B are partitioned by the Peltier element 103. In this Peltier element 103, the cooling surface 103A faces the air supply side duct 41B, and the heat radiation surface 103B faces the vent hole 45C. In the branch duct 101, a heat sink 105 is provided facing the heat radiating surface 103 </ b> B, and an exhaust fan 107 is provided by the heat sink 105. Thereby, heat does not accumulate on the heat radiating surface 103B, and the temperature of the cooling surface 103A can be lowered.

  Here, since the cooling surface 103A faces the air supply side duct 41B, the air flowing through the air supply side duct 41B is cooled by the cooling surface 103A. For this reason, low temperature air can be sent into the process cartridge 14, and the cooling effect in the process cartridge 14 can be enhanced.

1 is a diagram illustrating an outline of a printer according to an embodiment. It is sectional drawing which shows the process cartridge of the printer of this embodiment. It is a perspective view showing a process cartridge of the printer of this embodiment. FIG. 3 is an exploded perspective view showing a photosensitive unit of a process cartridge of the printer according to the embodiment. FIG. 3 is an exploded perspective view illustrating a developing unit of a process cartridge of the printer according to the embodiment. It is sectional drawing which shows the image development unit of the process cartridge of the printer of this embodiment. 1 is a perspective view illustrating a printer according to an embodiment. It is a figure which shows the flow of the wind by the air blower of the printer of this embodiment. It is a perspective view which shows the process cartridge of the printer of this embodiment, an air blower, and a laser exposure apparatus. 2A and 2B are diagrams illustrating a power supply unit disposed in an exhaust path of the printer according to the present embodiment, in which FIG. It is sectional drawing which shows the modification of the air blower of the printer of this embodiment.

Explanation of symbols

10 Printer (image forming device)
14 Process cartridge 28 Photosensitive drum (photosensitive member)
38 Exposure window 40 Blower (blower)
47 Branch duct
49 Guide duct 55 Power supply unit 63 Ozone filter 103 Peltier element (cooling member)
L2 air circulation path (air circulation flow)
L3 Branch path L4 Air supply path L5 Exhaust path

Claims (6)

A process cartridge in which at least a photosensitive member for transferring a developer to a recording medium is stored, and an exposure window for allowing information light to form a latent image on the photosensitive drum to enter the photosensitive member;
A blowing means for sending air into the process cartridge from one end of the exposure window and flowing air from one end to the other end in the axial direction of the photosensitive member;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the blowing unit forms an air circulation flow in which air exits from the other end of the exposure window and enters one end of the exposure window. An air supply path through which air of the air circulation flow and outside air flow;
An exhaust passage;
A branch path for branching air to the exhaust path and the exposure window;
The image forming apparatus according to claim 2, further comprising:   The image forming apparatus according to claim 2, further comprising a cooling member that cools the air in the air circulation flow.   The image forming apparatus according to claim 3, further comprising an ozone filter that is provided in the exhaust path and collects ozone generated in the process cartridge. A process cartridge having at least a photosensitive member for transferring a developer on a recording medium, and an exposure window for allowing information light to form a latent image on the photosensitive member to be incident on the photosensitive member;
A process cartridge comprising a guide duct provided at least at one end of the exposure window and for guiding air from the one end into the process cartridge.

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