JP2014013274A - Frame structure of image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide frame structure of an image forming apparatus that has high strength and high dimensional accuracy, and is light-weight and inexpensive, so as to address an increase in size and speed of the image forming apparatus.SOLUTION: L-shaped frame structure 400 is formed in an L-shape as a single body by folding a frame structure member 40 constituted by linearly connecting a plurality of frames 40a to 40g having a C-shaped cross-section at bending parts formed at connection parts of the frames so as to constitute a one-face square frame 400A; folding remaining frames connected to the one-face square frame 400A at bending parts formed at connection parts; and constituting a two-face square frame 400B.

Description

  The present invention relates to a frame structure of an image forming apparatus for holding each component (including a unit configuration) constituting the image forming apparatus.

  As a frame structure (casing structure) of an image forming apparatus that is generally used, there is one manufactured by punching a sheet metal by press working. A sheet metal is pressed and punched, and the frame structure is such that various components (including the unit configuration) constituting the image forming apparatus are held between the front and rear frames. As another method, it is known to form a frame structure in which a casing (frame) is formed by integral molding of resin and various components are positioned in the casing.

  However, in the structure of a frame structure in which sheet metal is pressed, deflection (distortion) occurs in the front and rear sheet metal frames that serve as the base of the holding frame for various components due to an increase in the size of the apparatus and an increase in the speed of image forming operations. Likely to happen. For this reason, the positional accuracy between the various components cannot be maintained due to changes over time. For example, in the case of an image forming apparatus that optically scans the surface of a photoconductor with a laser beam, even if the laser beam irradiation unit and the photoconductor are held so as to maintain the positional accuracy, distortion of the frame occurs due to the strength of the frame. Will occur. As a result, position accuracy cannot be secured due to distortion or twisting of the frame.

  In addition, when the processing speed of the apparatus is increased, distortion is likely to occur due to vibration of the apparatus itself in the front and rear sheet metal frames that are also the base of the holding frame, and the positional accuracy between various components is as described above. I can't keep it. As described above, this causes vibration in the apparatus main body due to a problem of frame strength and the like. As a result, a deviation occurs, leading to deterioration in image quality.

  Furthermore, in the structure of the frame structure by integral molding of resin, the positional accuracy between each component can be ensured to some extent. However, the resin integral molding method is limited in terms of the manufacturing method depending on the size of the housing and the cost for increasing the size. For this reason, there is a limit to adopting it for a large-sized apparatus, a high-speed processing apparatus, and the like.

  Thus, for example, Patent Document 1 clearly describes a technique in which a hollow steel material having a plurality of rectangular cross-sectional shapes is joined to form a frame structure, and various components are held by the frame structure.

  By adopting this configuration, a frame structure with a rectangular hollow steel material as the skeleton is configured even for a large apparatus, so that the strength of the holding structure can be ensured and the mounting work of various components can be simplified. This leads to a great merit. Patent Document 2 discloses a technique in which a frame structure is configured using a steel material having a U-shaped cross-sectional shape instead of a rectangular hollow steel material to further reduce the weight. Since the U-shaped steel material having a cross-sectional shape has a configuration in which one surface of the rectangular hollow steel material is removed as compared with the rectangular hollow steel material, the weight can be further reduced.

Japanese Patent No. 3679259 Japanese Patent No. 3586115

  By the way, in the recent copying machine market, digitization has progressed, and in the printer market, the size and speed of the apparatus have increased.Accordingly, the positional accuracy between various components has been improved and the vibration and distortion of the apparatus body have been improved. Reduction is required at a higher level. Accordingly, higher strength and dimensional accuracy are required for the frame structure of the image forming apparatus.

  The image forming apparatus includes an image reading device that reads an image. This image reading apparatus is provided with means for optically scanning an original for reading an original image, and irradiates light of an image by the scanning means to a target position, for example, a photoconductor as a recording medium, or a CCD. The reading element is irradiated. For this reason, it is necessary to support various components including the scanning means with increased positional accuracy.

  However, since the frame structure of Patent Documents 1 and 2 assembles a frame frame body by connecting rectangular hollow steel materials or U-shaped steel materials to each other, a plurality of connection fixing portions are required. Moreover, in the fastening part, the steel materials are used extra for the portions for assembling the respective steel materials and the portions for engaging the steel materials themselves. Therefore, the weight of the frame structure is increased, the assembly is difficult, the cost is increased, and the dimensional accuracy is decreased.

  This is because the weight and cost of the fastening portion used at each connection fixing location, the labor and cost for assembling a plurality of steel materials are generated. Further, when assembling the respective steel materials, slight deviations in dimensional accuracy that occur at each connection and fixing point are accumulated, resulting in a decrease in dimensional accuracy.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a frame structure for an image forming apparatus that is both lightweight and inexpensive while improving both strength and dimensional accuracy.

  The above object is achieved by the frame structure according to the present invention. In summary, according to the present invention, in the frame structure of the image forming apparatus, a frame structure member configured by connecting a plurality of U-shaped cross-section frames in a straight line is connected to the connecting portion of each frame. The first side square frame is formed by bending at a bent portion formed on the first side, and the frame connected to the first side square frame is perpendicular to the first side square frame by 90 degrees at the bent portion. It is formed integrally with the L-shape by forming a square frame on the second surface by bending and bending at the bent portion formed at the connecting portion of each frame of the remaining frame structure member including the frame. A frame structure characterized by being an L-shaped frame structure.

  According to the present invention, a member formed by connecting U-shaped cross-section frames in a straight line is bent at a bent portion formed at a connecting portion of each frame, thereby forming a square for two surfaces in an L shape. The frame is constructed integrally. This eliminates the need for the weight and cost of the fastening parts used at each joint and fixing point, and prevents the frame structure from increasing in weight and cost.

  In addition, since minute deviations in dimensional accuracy that occur at each joint location are not stacked, it is possible to form a frame with better dimensional accuracy.

1 is a schematic overall configuration diagram showing an embodiment of an image forming apparatus according to the present invention. It is a figure which shows the frame structure of Example 1. FIG. FIG. 2A is a perspective view showing a frame structure integrally formed in an L shape, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A of members constituting the frame structure. It is a figure showing the U-shaped part dimension in each location in a BB, CC, DD cross section. It is a perspective view which shows the frame structure of Example 1, Fig.3 (a) is a figure before the assembly work of a frame structure. FIG. 3B is a diagram in which the first bent portion of the member constituting the frame structure is bent. It is a figure showing the order which bends the bending part of the member which comprises the frame structure of Example 1, and forms a frame structure. FIG. 4A is a diagram in which the second bent portion of the member constituting the frame structure is bent, and FIG. 4B is a graph in which the third bent portion of the member constituting the frame structure is bent. FIG. Moreover, FIG.4 (c) is the schematic perspective view seen by C view in FIG.4 (b). It is a figure showing the order which bends the bending part of the member which comprises the frame structure of Example 1, and forms a frame structure. FIG. 5A is a diagram in which the fourth bent portion of the member constituting the frame structure is bent, and FIG. 5B is a diagram in which the fifth bent portion of the member constituting the frame structure is bent. It is. It is an expanded view of the member which comprises the frame structure of Example 1. FIG. 1 is a schematic perspective view of a box-shaped frame structure according to Embodiment 1. FIG. 6 is a schematic perspective view of a box-shaped frame structure according to Embodiment 2. FIG. It is a schematic perspective view of the frame structure of Example 2. It is an expanded view of the member which comprises the frame structure of Example 2. FIG.

  Hereinafter, the frame structure of the image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

[Example 1]
FIG. 1 is a schematic overall configuration diagram showing an example of an image forming apparatus according to the present embodiment. First, the configuration of the image forming apparatus of this embodiment will be described with reference to FIG.

  An image forming apparatus 100 shown in FIG. 1 is a drum-shaped electrophotographic photosensitive member (image bearing member) that forms toner images of each color of yellow (Y), magenta (M), cyan (C), and black (K). (Hereinafter referred to as “photosensitive drum”.) Four 10Y to 10K are arranged. A charger, a developer, and a cleaner (not shown) are arranged around the photosensitive drums 10Y to 10K, respectively, and are unitized as process cartridges 1Y to 1K. The process cartridges 1 </ b> Y to 1 </ b> K can be attached to and detached from the image forming apparatus 100. Above these process cartridges 1Y to 1K, a belt-shaped intermediate transfer belt 2 as an intermediate transfer member is disposed so as to be in contact with each of the photosensitive drums 10Y to 10K.

  The surface of each of the photosensitive drums 10Y to 10K is uniformly charged by a charger (not shown). Next, the color separated yellow, magenta, cyan and black light images are exposed by the exposure device 6 to form yellow, magenta, cyan and black electrostatic latent images on the photosensitive drums 10Y to 10K. Each electrostatic latent image is developed by a developing device corresponding to each toner color, and yellow, magenta, cyan, and black toner images are formed on the photosensitive drums 10Y to 10K.

  With the rotation of the photosensitive drums 10Y to 10K, the toner images arrive at the primary transfer portions T1Y to T1K where the photosensitive drums 10Y to 10K and the intermediate transfer belt 2 are in contact with each other. The toner images are sequentially transferred to the intermediate transfer belt 2 that is a rotating image carrier by primary transfer rollers 2Y to 2K disposed opposite to the photosensitive drums 10Y to 10K, and a multicolor image is formed. The A primary transfer bias is applied to the primary transfer rollers 2Y to 2K from an electrical board described later.

  The sheets P stored in the feeding cassette 4 are fed one by one by the pickup roller 8, and after the timing is adjusted by the registration roller 9, the sheet P is composed of the secondary transfer roller 3 and the intermediate transfer belt 2. Is transferred to the transfer nip T2. The toner images, which are multicolor images on the intermediate transfer belt 2, are secondarily transferred onto the sheet P at a time at the transfer nip T 2. Thereafter, the sheet P on which the toner image is transferred is conveyed to the fixing device 5 where the toner image is fixed by receiving heat and pressure. As a result, the toner of each color is melted and mixed to form a full-color print image fixed on the sheet P, and then discharged to the discharge tray 7 by the discharge conveying means 21 provided downstream of the fixing device 5.

  The arrangement of each part in the apparatus will be described. The image forming apparatus 100 according to the present exemplary embodiment has a feeding cassette 4, an exposure apparatus 6, process cartridges 1 </ b> Y to 1 </ b> K, the intermediate transfer belt 2, and a discharge tray from below the main body 30. 7 are arranged in this order.

  By the way, in such an image forming apparatus, since it is multifunctional, the number of various components is large and the size is increased. Further, improvement in positional accuracy between various components and reduction of vibration and distortion of the apparatus main body are required at a higher level. For this reason, the frame structure of the image forming apparatus is also required to have higher strength, dimensional accuracy, and a larger size.

  Hereinafter, a frame structure which can improve both strength and dimensional accuracy, which is a characteristic part of the present invention, and can cope with an increase in size will be described.

  FIG. 2A is a perspective view showing a frame structure 400 in which two square frames 400A and 400B are integrally formed in an L shape. This frame structure 400 has a U-shaped member (frame) 40 comprising a base portion 41A and rising portions 41B and 41C from the base portion 41A as shown in FIG. It is formed by bending at a bent portion formed between ˜40 g.

  2A, the dimensions of the members in the AA, BB, CC, and DD sections shown in FIG. 2B are as shown in FIG. This dimension represents a dimension necessary for combining the U-shaped members of the frame in the processing steps described in FIGS. 3 (a) to 5 (b). Details will be described later.

  First, the process of processing the U-shaped frame in the present embodiment will be described. FIG. 3A is a perspective view of a frame structure member 40 in which a plurality of U-shaped frames are connected. In the frame structure member 40 in which the U-shaped frames are connected, the frames 40a to 40g processed so as to be U-shaped for each side of the frame structures 400A and 400B are linear. Concatenated. Between the frames connected to each other and the other frames (40a and 40b, 40b and 40c, 40c and 40d, 40d and 40e, 40e and 40f, 40f and 40g), that is, a portion bent at the connecting portion (bending portion) (Ab, bc, cd, de, ef, fg) are provided. Each bent portion is formed on a base portion 41A that connects the U-shaped frames 40 to each other except the bent portion de. The bent portion de is formed at the connecting portion of the rising portion 41B or 41C of the frame 40e adjacent to one rising portion 41B or 41C of the frame 40d connecting the frames 40d and 40e. In addition, parts other than the connection part between adjacent frames are separated.

  A frame structure member 40 configured by a combination of a frame and a bent portion (ab, bc, cd, de, ef) for each side of a U-shaped cross section as shown in FIG. I will do it. First, as shown in FIG. 3B, the frame 40a is bent at 90 degrees perpendicular to the frame 40b at the bent portion ab which is the first bent portion. At this time, the frame 40a is formed so as to enter the inside of the frame 40b due to the difference in dimensions of the respective frames shown in FIGS. 2 (a) and 2 (b).

  Next, as shown in FIG. 4A, the frame 40b is bent 90 degrees perpendicular to the frame 40c at the bent portion bc which is the second bent portion. At this time, the frame 40c is formed so as to enter the inside of the frame 40b.

  Next, as shown in FIG. 4B, the frame 40c is bent 90 degrees perpendicular to the frame 40d at the bent portion cd. At this time, the frame 40c is formed so as to enter the inside of the frame 40d. Then, the first frame 400A is formed.

  Further, as shown in FIGS. 4 (b) and 5 (a), the U-shaped raised portion 41B of the frame 40e connected to one raised portion 41B of the U-shaped frame 40d constituting the square frame 400A. At the formed bent portion de, the frame 40e is bent 90 degrees perpendicular to the U-shaped raised portion 41B of the frame 40d. At this time, the frame 40d and a part of the frame 40e interfere with each other. Therefore, as shown in FIGS. 3A, 3B, 4B, and 4C, a notch such as the frame 40e-AC is provided in advance in the frame 40e. Then, after bending as shown in FIG. 5A, the end of the frame 40d and the joint of the frame 40e are fastened by using fastening means F such as welding to complete the first frame 400A.

  Next, the formation of the square frame 400B which becomes the second surface of the L-shaped frame structure starts. As shown in FIG. 5B, the frame 40f is bent 90 degrees perpendicular to the frame 40e at the bent portion ef. At this time, the frame 40f is formed so as to enter the inside of the frame 40e. Further, as shown in FIG. 2A, the frame 40g is bent 90 degrees perpendicular to the frame 40f at the bent portion fg. At this time, the frame 40f is formed so as to enter the inside of the frame 40g. Then, the frame 40a and the end portion 40g1 of the frame 40g are joined and fastened by using fastening means F such as welding to form a square frame 400B on the second surface, and an L-shape shown in FIG. The frame structure 400 is completed.

  Next, a more detailed description will be given with reference to FIGS.

  FIG. 6 shows a blank which is a schematic development view of the frame structure member 40 including each frame. Here, the case where the frame structure member 40 is formed of a plate-shaped steel material (steel plate) having a thickness t is considered.

  A steel plate or the like that can be bent and has a certain degree of strength is formed into a shape as shown in FIG. 6 in advance, and first, the U-shaped frames 40a to 40g are formed. At this time, as described above, the frames 40a to 40d and 40e to 40g are connected by the base portion 41A, and the frames 40d and 40e are connected by the rising portion 41B. Further, the adjacent rising portions 41B and 41B and 41C and 41C in the frames 40a to 40d and 40e to 40f are separated from each other.

  Next, the above-described L-shaped frame structure 400 can be formed by a method of bending each bent portion (ab, bc, cd, de, ef, fg). Since each bent part has already been determined and is formed simply by bending it, there is no need to fasten individual members as in Patent Documents 1 and 2 each time at the fastening part, and dimensional errors are not accumulated. . Therefore, a frame structure can be produced with higher dimensional accuracy than the conventional method of fastening individual members each time.

  Moreover, since the part for fastening of each member can be restrained less than the time of manufacture of the frame structure body by the conventional method, the cost as the whole member can be restrained.

  It is also easy to change the lengths L1 to L3 of the frames 40a to 40g according to the required dimensions of the frame structure 400. The frame structure member 40 in the present embodiment does not need to punch a sheet metal with a press, cuts a sheet metal having a necessary width and length, and provides a cut or bent portion at a predetermined location. The structural member 40 can be manufactured. Therefore, it is not necessary to prepare a mold for pressing the sheet metal each time, and the manufacturing cost can be reduced.

  Here, the frame structure member 40 is a steel material, but it may be not only a steel material but also other metals or a plate-shaped resin that can be bent.

  Then, as shown in FIG. 7, by combining the molded first L-shaped frame structure 400 and the L-shaped frame structure 400 having the same shape, the entire box-shaped frame structure 500 is obtained. Is completed. That is, the two L-shaped structures 400 and 400 are combined and fastened using fastening means such as welding, so that a box-shaped frame structure 500 is formed.

  Next, the dimensions of each frame will be described. Here, the frames 40a to 40d are access surfaces to the process cartridges 1a to 1d, the intermediate transfer belt 2, and the paper feed cassette 4 as shown in a plane A (a dashed-dotted enclosing surface) in FIG. On the surface A, a certain space is required as an access surface when the process cartridge is attached / detached or the recording medium is replenished to the paper feed cassette 4. Further, support members for supporting members such as process cartridges and paper feed cassettes are connected to the frames 40a to 40d, so that higher strength is required. As shown in the cross sections AA and DD in FIG. 2A, the dimensions satisfying the accessibility and strength are the U-shaped base 41A dimensions X and X + 2t serving as a reference, and the U-shaped raised portion 41B ( 41C) The dimension Y is defined as 3 / 4X or less. The U-shaped raised portion 41B (41C) size Y is defined as a size smaller than the U-shaped base portion 41A size X in consideration of accessibility to each device from the surface A. This makes it possible to secure a wide access space from the surface A side to each device.

  2B, the frame 40e and the frame 40g both have a U-shaped base 41A dimension and a rising part 41B (41C) dimension of Y = 3 / 4X or less. This is because the U-shaped base 41A dimension Y of the frames 40e and 40g is larger than the U-shaped raised portion 41B (41C) dimension Y of the frames 40a to 40d when accessing each device from the surface A side shown in FIG. This is because the space for accessing each device from the surface A is reduced when the size is increased. Similarly, the U-shaped raised portion 41B (41C) dimension Y has the same dimensions as the frames 40a to 40d on the surface A side in consideration of the accessibility to the registration roller 9 and the fixing device 5 from the surface B. did. This makes it possible to secure a wide access space from the surface B side to each device while maintaining the strength.

  3B, the frame 40f has a U-shaped base portion 41A dimension Z = Y-2t, and a U-shaped raised portion 41B (41C) dimension W = 1 / 2X or less. did. Since the frame 40f is a part where two L-shaped frame structures 400 are joined and fastened as shown in FIG. 7, the dimensions of the U-shaped base portion 41A and the U-shaped raised portion 41B (41C) are the same. There is no problem in strength even if it is reduced. 7 is an access surface to the registration roller 9, the fixing device 5, and the like in the image forming apparatus 100. In order to ensure accessibility to each device from the surface B side, the U-shaped raised portion 41B (41C) dimension W is set to W = 1 / 2X, so that a wide access space can be secured. .

  As described above, the frame structure 500 of the image forming apparatus 100 can be manufactured with high accuracy and at low cost.

[Example 2]
Next, a second embodiment will be described with reference to FIGS. The second embodiment is different from the first embodiment in that an L-shaped frame structure 400 is provided with a frame that forms a bracing.

  In addition, since the structure of most of the frame of a present Example is the same as that of Example 1, the same component is shown with the same code | symbol, uses description of Example 1, and abbreviate | omits the detail. Here, only a different part from Example 1 is demonstrated.

  In the first embodiment, a rectangular frame 400A is configured by bending a frame structure member 40 configured by connecting U-shaped cross-section frames linearly at a bent portion formed at a connecting portion of each frame. In addition, the L-shaped frame structure 400 that is configured integrally with the L-shape by extending a part of the square frame 400A and bending the second-side square frame 400B has been described. Furthermore, the frame structure 500 of the image forming apparatus in which two L-shaped frame structures 400 are joined and fastened in a box shape has been described. However, in this frame structure, the strength of the frame structure may be insufficient due to the strength of the members.

  In the present embodiment, a case where a structure for reinforcing when strength is insufficient as described above will be described.

  The present embodiment is different from the first embodiment in the configuration in which a frame 40h that is a bracing is provided on the second rectangular frame 400B of one L-shaped frame structure 410.

  FIG. 8 is a perspective view showing a frame structure 500 of the image forming apparatus 100 according to the present embodiment. As shown in the figure, a frame 40h is provided. The L-shaped frame structure 410 and the L-shaped frame structure 410 provided with a frame 40h that is a bracing on the square frame 400B on the second surface are combined. Then, the frames 40c and 40f of the L-shaped frame structure 410 are joined to the L-shaped frame structure 400, and fastened using fastening means such as welding, so that a box-shaped frame structure with higher strength is obtained. The body 500 can be formed.

  Further, by configuring one of the two L-shaped frame structures constituting the box-shaped frame structure 500 with the L-shaped frame structure 400 having no bracing, the registration rollers 9 and Accessibility to the fixing device 5 is ensured.

  FIG. 9 is a perspective view of an L-shaped frame structure 410 provided with braces. The processing steps of the L-shaped frame structure 410 and the cross-sectional shape of the U-shaped frame in this embodiment are the same as those of the L-shaped frame structure 400 of the first embodiment, and thus the description thereof is omitted. Only the processing steps of the frame 40h to be changed are different.

  FIG. 10 is a schematic development view (blank) of the frame structure 410 of the present embodiment.

  As can be understood with reference to FIG. 10, after bending the bent portions ab, bc, cd, de, and gh1 up to the frames 40a to 40d, the frame 40g is bent 90 degrees perpendicular to the frame 40f (bent). While bending the frame 40h, the bent portion gh2 of the frame 40g end rising portion 41D is bent 90 degrees or less, for example, 45 degrees. Then, the end of the frame 40h is fastened to the inside of the frame 40f using fastening means such as welding. The bending angle is determined by the length of the frame 40f and the frame 40g and the end of the frame 40g that define the depth of the final frame structure 500 in the photosensitive drum rotation axis direction and the height of the frame structure. It is defined by the dimension of the part rising part 41D (FIG. 10). Thereafter, the frame 40f is bent 90 degrees perpendicular to the frame 40e, the end of the frame 40g is joined to the frame 40a, and fastened using fastening means such as welding, whereby the L-shaped frame structure 410 is obtained. Complete.

Further, as shown in FIG. 9, the bracing frame 40h is bent so as to enter the inside of the frame 40f portion. Therefore, as shown in the developed view of FIG. 10, the dimension of the U-shaped rising base 41A of the frame 40h is V = Z−2t = Y−4t obtained by further subtracting the member thickness from the dimension of the frame 40f. The length L ₄ of the frame 40h is defined by the lengths of the frames 40f and 40g and the end rising portion 41D (FIG. 10) of the frame 40g, similarly to the angle of the bent portion.

  As described above, the strength of the box-shaped frame structure 500 is further increased than that of the first embodiment by adopting a configuration in which only one of the two L-shaped frame structures has a bracing frame. It is possible to manufacture a box-shaped frame structure 500 that improves the above and secures accessibility to internal components.

1Y to 1K Process cartridge 2 Intermediate transfer belt 4 Paper feed cassette 5 Fixing device 6 Exposure device 7 Discharge tray 8 Pickup roller 100 Image forming apparatus body 40 Frame structure members 40a to 40h U-shaped frames 400, 410 L-shaped Frame structure 400A, 400B Square frame 500 Box-shaped frame structure ab, bc, cd, de, ef, fg, gh1, gh2 Bending part

Claims (3)

In the frame structure of the image forming apparatus,
A frame structure member configured by connecting a plurality of U-shaped cross-section frames in a straight line,
The first side of the square frame is configured by bending at the bent portion formed in the connecting portion of each frame,
Further, the frame connected to the square frame on the first surface is bent 90 degrees perpendicular to the square frame on the first surface at a bent portion, and the frames are connected to the remaining frame structure members including the frame. A frame structure that is an L-shaped frame structure that is formed integrally with an L-shape by forming a square frame on the second surface by bending at a bent portion formed in the portion.   2. The frame structure according to claim 1, wherein the two L-shaped frame structures are combined, joined, and fastened to form a box-shaped frame structure.   One of the two L-shaped frame structures constituting the box-shaped frame structure is further extended at an end of the frame structure member, and formed at a connecting portion of each frame. 3. The frame structure according to claim 1, wherein the frame structure is provided in a square frame on a second surface of the L-shaped frame structure by bending at a bent portion.

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