JP4842535B2 - Image reading unit, scanner device, and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading unit used in a copying machine, a facsimile, a scanner device, and the like, a scanner device including the image reading unit, and an image forming apparatus.

  2. Description of the Related Art Conventionally, an image reading unit used for a copying machine, a facsimile machine, a scanner device, or the like is known having an imaging lens system composed of two or more lens groups. In this conventional image reading unit, the illumination light source of the document is moved in the sub-scanning direction, and the reflected light from the document is reduced and imaged on the line type photoelectric conversion element through the imaging lens system. The imaged light beam formed on the light is photoelectrically converted and output as an image reading signal.

  In that image reading unit, if the imaging light beam deviates in the optical axis direction from the light receiving surface of the line type photoelectric conversion element, the read image deteriorates. The distance between the lens groups is adjusted to satisfy the above.

  In this image reading unit, the central rectangular portion of the surface of the lens constituting the lens group contributes to the image formation of the line type photoelectric conversion element. The imaging performance such as aberration of the rectangular portion varies in the circumferential direction around the optical axis of the lens. Therefore, the lens is positioned so that the rectangular portion is parallel to the line photoelectric conversion element, and the lens and the line are formed so that the imaging position of the imaging light beam is imaged on the light receiving surface of the line photoelectric conversion element. Even if the distance from the photoelectric conversion element is adjusted, if the lens is rotated, the imaging position of the imaging light beam may be shifted from the light receiving surface of the linear photoelectric conversion element in the optical axis direction, resulting in degradation of image quality. Was sometimes invited.

  In particular, in a lens used in an image reading unit for reading a color image, if the imaging position is shifted in the rotation direction of the lens at a blue wavelength, a green wavelength, and a red wavelength, the color image can be reproduced well. It will not be possible. Therefore, it is also necessary to adjust the lens in the circumferential direction around the optical axis.

Conventionally, in order to improve the image quality by adjusting the distance between the lenses and the circumferential position around the optical axis of the lens, one lens barrel is divided into two parts. The group is held by both split lens barrels, a thread is formed on one outer periphery of both split lens barrels, and a thread groove is formed on the other inner periphery, and these threads and screw grooves are screwed together. In addition, there is known a configuration in which the distance between the lens groups is adjusted by relatively rotating both split lens barrels around the optical axis (see, for example, Patent Document 1).
JP 11-337799 A

  However, in the image reading unit described in Patent Document 1 described above, when the distance between the lens groups held in each divided lens barrel is adjusted, each lens group rotates as the divided lens barrel rotates. There is a problem that the position in the circumferential direction around the optical axis of the lens group may be shifted due to aberrations or the like, and that the rotation of the lens group and the interval adjustment cannot be performed independently.

  In addition, in the image reading unit described in Patent Document 1 described above, in order to suppress backlash between the screw thread and the screw groove, a contrivance is provided in which a guide portion in the rotation direction is provided in the divided barrel. However, if the axis of the guide portion and the center of the optical axis of the lens are decentered, the optical axis rotates around the axis of the guide portion with the rotation of the split lens barrel. In order to prevent the optical axis of the lens from rotating around the axis of the guide part, the lens barrel itself must be manufactured with high precision, and in addition to the complexity of the lens barrel shape, its manufacture It is also difficult.

  The present invention has been made in view of the above circumstances, and independently rotates the lens barrel and adjusts the distance between the lens barrels with a simple configuration without complicating the structure of the lens barrel. An object of the present invention is to provide an image reading unit, a scanner device using the same, and an image forming apparatus that can easily obtain necessary lens characteristics.

In order to solve the above-described problems and achieve the object, an image reading unit according to a first aspect of the present invention includes at least two lens barrels that store a lens group that forms a reflected image from a document on a photoelectric conversion element. An imaging lens system, a base member to which both the photoelectric conversion element and the imaging lens system are attached, an intermediate holding member attached to both the lens barrel and the base member, The at least one lens barrel is supported by the intermediate holding member at a distance from the base member, and the intermediate holding member intersects substantially vertically 2. has a face, one side is adhered and fixed to the base member, through the other side is adhered and fixed to the lens barrel, passing through the base member to the position where the lens barrel of said base member overlaps And a narrow portion arranged in parallel with the intermediate holding member along a direction in which the through hole intersects the optical axis of the imaging lens system, and the light of the imaging lens system A wide portion provided in parallel with the intermediate holding member along an axis, and the width of the wide portion from the width of the narrow portion in a direction intersecting the optical axis of the imaging lens system. It is characterized by a wide width in a direction intersecting the optical axis of the imaging lens system .

The image reading unit according to a second aspect of the present invention is the image reading unit according to the first aspect of the present invention, wherein a part of the imaging lens system is inserted into the through hole. It is characterized by.

The image reading unit of the present invention described in claim 3 is the image reading unit of the present invention described in claim 1 or 2, wherein the lens barrel includes a large-diameter portion to which the intermediate holding member is attached; And a small-diameter portion continuous with the large-diameter portion and having a smaller diameter than the large-diameter portion .

The image reading unit according to a fourth aspect of the present invention is the image reading unit according to the third aspect of the present invention, wherein the outer diameter gradually decreases as the small diameter portion moves away from the large diameter portion. It is characterized by being formed as follows.

An image reading unit according to a fifth aspect of the present invention is the image reading unit according to the third or fourth aspect of the present invention, wherein the small-diameter portion is arranged in the wide portion . .

Image reading unit of the present invention described in claim 6 is the image reading unit of the present invention according to any one of claims 3 to claim 5, said large diameter portion and the small diameter portion is coaxially It is characterized by being arranged in .

Image reading unit of the present invention described in claim 7 is the image reading unit of the present invention described in claims 1 any one of claims 6, and the lens barrel, in the lens barrel The lens groups to be accommodated are arranged coaxially with each other .

Image reading unit of the present invention according to claim 8, in the image reading unit of the present invention described in claims 1 any one of claims 7, at least one lens barrel, the lens Two or more are accommodated, and the intermediate holding member is juxtaposed along the direction orthogonal to the optical axis and the lens group that most affects the image formed by the photoelectric conversion element of the two or more lens groups. It is characterized by having.

The image reading unit according to the present invention described in claim 9 is the image reading unit according to any one of claims 1 to 8, wherein the intermediate holding member is at least one lens barrel. Further, a plurality of the imaging lens systems are attached in parallel along the optical axis of the imaging lens system .

A scanner device according to a tenth aspect of the present invention is a scanner device that reads a reflected image from a document by a photoelectric conversion element, and includes the image reading unit according to any one of the first to ninth aspects. It is characterized by that.

An image forming apparatus according to an eleventh aspect of the present invention includes the scanner device according to the tenth aspect.

  As described above, according to the first aspect of the present invention, since the intermediate holding member supports the lens barrel at a distance from the base member, each lens barrel is supported with respect to the base member. It is possible to move along a direction contacting and separating from the base member (a direction perpendicular to the surface of the base member), two directions parallel to the surface of the base member and perpendicular to each other, and a rotation direction centering on these directions. Yes (position can be adjusted).

  In this way, with a simple configuration of providing a plurality of lens barrels that are separate from each other, adjustment of the rotation direction of the lens barrel and adjustment of the distance between the lens barrels can be performed independently of each other. Therefore, necessary lens characteristics can be obtained easily and reliably. Furthermore, since necessary lens characteristics can be obtained easily and reliably, the number of assembling steps for the image reading unit can be reduced.

  According to the second aspect of the present invention, since the through hole is provided in the base member, a space in which the lens barrel can be gripped in the through hole can be secured. Therefore, the position adjustment and fixing of the lens barrel can be easily performed, so that the number of assembling steps can be reduced.

  Further, by providing the through hole, the position of the lens barrel can be easily adjusted and fixed, so that the shape of the base member can be simplified. Therefore, the cost of parts can be reduced.

  According to the third aspect of the present invention, since the planar shape of the through hole is formed larger than the planar shape of the imaging lens system, a space in which the lens barrel can be gripped can be reliably secured in the through hole. Therefore, the assembly man-hour can be reduced.

  According to the fourth aspect of the present invention, since a part of the imaging lens system is accommodated in the through hole, the amount of projection from the base member of the imaging lens system can be suppressed, and the thickness of the image reading unit is suppressed. it can. Therefore, it is possible to reduce the size of the image reading unit.

  According to the fifth aspect of the present invention, since the through hole is provided with a wide portion that is wider than the narrow portion, a space in which the lens barrel can be grasped through the wide portion can be secured. Therefore, the lens barrel can be easily adjusted and fixed, and the number of assembling steps can be reduced.

  According to the sixth aspect of the present invention, since the lens barrel includes a small diameter portion thinner than the large diameter portion, the lens barrel can be easily grasped by grasping the small diameter portion, and the position of the lens barrel It is possible to prevent the unit or the like that holds the lens barrel from interfering with the base member when adjusting. Therefore, the position adjustment of the lens barrel can be reliably performed.

  According to the seventh aspect of the invention, since the small diameter portion is tapered, the play (gap) between the small diameter portion and the chuck of the adjusting device (assembly device) can be reduced. As a result, the positioning of the lens group and the chuck of the adjustment device (assembly device) can be reliably performed, the positioning accuracy of the lens group can be improved, the lens group can be easily adjusted, and the number of assembly steps can be reduced. it can. Also, if the small diameter part and the lens group are coaxial, the lens group can be rotated without rotating the optical axis of the lens group away from the target axis when the lens barrel is rotated around the axis. The lens group can be easily adjusted, and the number of assembling steps can be further reduced.

  According to the eighth aspect of the present invention, since the small diameter portion of the lens barrel is positioned within the wide portion of the through hole, the small diameter portion can be reliably grasped, and the lens barrel can be adjusted when adjusting the position of the lens barrel. It is possible to reliably prevent the unit that holds the lens barrel from interfering with the base member. Therefore, the position adjustment of the lens barrel can be reliably performed.

  In the ninth aspect of the present invention, since the large diameter portion and the small diameter portion are coaxial, the lens group inserted into the large diameter portion and the lens group inserted into the small diameter portion are coaxial. Therefore, necessary lens characteristics can be obtained easily and reliably, and the number of assembling steps for the image reading unit can be reduced.

  According to the tenth aspect of the present invention, since the lens barrel and the lens group are coaxial with each other, the optical axis of the lens group is rotated by the lens barrel when the lens barrel is rotated to adjust the position. It can prevent rotating away from the center. Therefore, the position adjustment of the lens barrel and the lens group in the rotation direction can be easily performed, and the number of assembling steps for the image reading unit can be reduced.

  According to the eleventh aspect of the present invention, an intermediate holding member is attached to a lens group in which the positional deviation has the most influence on the image characteristics in the lens group and a position along the direction orthogonal to the optical axis. Therefore, when the lens barrel vibrates, it is possible to suppress the vibration of the lens group that most affects the image characteristics. Therefore, it is possible to provide an image reading unit whose image characteristics are not easily affected by vibration.

  According to the twelfth aspect of the present invention, since a plurality of intermediate holding members are arranged side by side along the optical axis in the lens barrel, vibration of the lens barrel due to vibration can be reduced. Therefore, it is possible to provide an image reading unit whose image characteristics are not easily affected by vibration.

  According to the thirteenth aspect of the present invention, since the image reading unit according to any one of the first to twelfth aspects is provided, a high-quality read image can be obtained.

  Since the present invention described in claim 14 comprises the scanner device of claim 13, a high-quality read image can be obtained, a high-quality electrostatic latent image can be formed, and a high-quality copy image can be formed. Can be formed.

  Hereinafter, an image forming apparatus, a scanner apparatus, and an image reading unit according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, an image forming apparatus 1 such as a copying machine or a facsimile includes an apparatus main body 2, an automatic document feeder 3, a scanner device 4, a paper feeding unit 5, and a writing unit 6. Yes.

  The apparatus main body 2 is formed in a box shape, for example, and is installed on a floor or the like. The apparatus main body 2 accommodates a scanner device 4, a paper feeding unit 5, and a writing unit 6.

  The automatic document feeder 3 is attached to the upper part of the apparatus body 2. The automatic document feeder 3 includes a document placing plate 7 and a belt feeder 8. The document placing plate 7 is formed in a flat plate shape, is attached to the upper part of the apparatus main body 2, and a plurality of documents 9 are placed on the surface. The belt feeding device 8 feeds the originals 9 on the original placing plate 7 one by one onto a contact glass 10 which will be described later, and the original 9 on which a reflection image has been read by an image reading unit 16 which will be described later is supplied from the contact glass 10. It is discharged out of the apparatus body 2.

  The scanner device 4 is provided above the apparatus main body 2 and below the automatic document feeder 3 described above, and includes a contact glass 10 on which a document is placed and an optical scanning system 11. The contact glass 10 is attached to the upper surface of the apparatus main body 2 with both surfaces parallel to the horizontal direction. The optical scanning system 11 includes an exposure lamp 12, a first mirror 13, a second mirror 14, a third mirror 15, an image reading unit 16, and the like. The optical scanning system 11 irradiates the document 9 with light and forms a reflected image from the document 9. Photoelectric conversion is performed by a line-type photoelectric conversion element 42 described later.

  The exposure lamp 12 irradiates the document 9 on the contact glass 10 with light. The first mirror 13, the second mirror 14, and the third mirror 15 guide the reflected image from the document 9 to the image reading unit 16. The exposure lamp 12 and the first mirror 13 are fixed on a first carriage (not shown), and the second mirror 14 and the third mirror 15 are fixed on a second carriage (not shown). When reading a document, the first carriage and the second carriage are mechanically moved at a relative speed of 2: 1 so that the optical path length does not change. The aforementioned first carriage and second carriage of the optical scanning system 11 are moved by a scanner drive motor (not shown).

  The image reading unit 16 includes an imaging lens system 31, an image sensor 32, and the like. The detailed configuration of the image reading unit 16 will be described later. The image reading unit 16 reads the above-described reflection image of the original by the image sensor 32, converts the optical signal into an electric signal, and processes it. The converted electrical signal is output toward an image processing unit (not shown). When the imaging lens system 31 and the image sensor 32 are moved in the left-right direction (horizontal direction) in FIG. 1, the image magnification can be changed. That is, the positions of the imaging lens system 31 and the image sensor 32 in the left-right direction in FIG. 1 are set corresponding to the specified magnification.

  The paper feed unit 5 includes a plurality of transfer paper storage portions 19 provided at the lower part of the apparatus main body 2 and a transfer paper feed unit 20. The transfer paper storage unit 19 stores a plurality of transfer papers 21. The transfer paper feed unit 20 sends the transfer paper 21 in the transfer paper storage unit 19 between registration rollers 25 described later. The paper feeding unit 5 feeds the transfer paper 21 in the transfer paper storage unit 19 one by one toward the registration roller 25, that is, the writing unit 6.

  The writing unit 6 includes a laser output unit 22, an imaging lens 23, a mirror 24, a registration roller 25, a photosensitive drum 26, a developing device 27, a transfer member 28, and a fixing device 29. Yes.

  Inside the laser output unit 22, a laser diode that is a laser light source and a polygon mirror that rotates at a constant speed by a motor are provided. Laser light emitted from the laser output unit 22 is deflected by the polygon mirror that rotates at a constant speed, passes through the imaging lens 23, is folded back by the mirror 24, and is condensed on the outer peripheral surface of the photosensitive drum 26. Image. The deflected laser light is exposed and scanned in a so-called main scanning direction orthogonal to the direction in which the photosensitive drum 26 rotates, and recording is performed in line units of an image signal output from an image processing unit (not shown). Then, the writing unit 6 forms an image, that is, an electrostatic latent image, on the outer peripheral surface of the photosensitive drum 26 by repeating main scanning at a predetermined cycle corresponding to the rotational speed and recording density of the photosensitive drum 26. .

  In this way, the laser light output from the writing unit 6 is applied to the photosensitive drum 26 of the image forming system, and a main scanning synchronization signal is generated at the irradiation position of the laser light near one end of the photosensitive drum 26. A beam sensor (not shown) is arranged. Based on the main scanning synchronization signal output from the beam sensor, control of image recording timing in the main scanning direction and generation of control signals for input / output of image signals, which will be described later, are performed.

  The registration roller 25 sends the transfer paper 21 sent from the transfer paper storage unit 19 by the transfer paper sending unit 20 between the transfer member 28 and the photosensitive drum 26. The photosensitive drum 26 is formed in a columnar shape or a cylindrical shape that is rotatable around an axis. The photosensitive drum 26 is developed by the toner attached to the electrostatic latent image formed and carried by the laser output unit 22, and the toner image thus obtained is transferred onto the transfer paper 21 positioned between the transfer member 28. Transcript.

  The developing device 27 causes toner to adhere to the outer peripheral surface of the photosensitive drum 26 and develops the electrostatic latent image on the outer peripheral surface of the photosensitive drum 26. The transfer member 28 presses the transfer paper 21 against the outer peripheral surface of the photosensitive drum 26 to transfer the toner on the outer peripheral surface of the photosensitive drum 26 to the transfer paper 21 and directs the transfer paper 21 toward the fixing device 29. Send it out. The fixing device 29 fixes the toner image formed on the photosensitive drum 26 and the like onto the transfer paper 21 and discharges the transfer paper 21 out of the apparatus main body 2.

  As shown in FIGS. 2 to 5, the image reading unit 16 includes a base portion 30, an imaging lens system 31, an image sensor 32, and a plurality of intermediate holding members 33. Hereinafter, a direction parallel to the optical axis O of the imaging lens system 31 is defined as a depth direction Z (also referred to as a Z-axis direction) shown in FIG. 2, and a direction orthogonal to the optical axis O and parallel to the surface of the base member 50. 2 is the width direction X (also referred to as the X-axis direction) shown in FIG. 2, and the direction perpendicular to both the optical axis O and the surface of the base member 50 is the thickness direction Y (also referred to as the Y-axis direction) shown in FIG. . Further, the rotation direction centering on the depth direction Z is defined as the γ direction, the rotation direction centering on the width direction X is defined as the α direction, and the rotation direction centering on the thickness direction Y is defined as the β direction.

  The base part 30 includes a slide base 49 and a base member 50 as shown in FIGS. The slide base 49 is formed in a flat plate shape and is housed in the apparatus main body 2 with both surfaces parallel to the horizontal direction. The slide base 49 is provided movably along the left-right direction in FIG. Further, a hole 51 larger than a through hole 55 described later passes through the center of the slide base 49. A through hole 55 overlaps the hole 51. Further, positioning holes 52 (shown in FIG. 9) are provided at both ends in the width direction X of the slide base 49.

  The base member 50 is made of a thick sheet metal, has a rectangular planar shape, and has a flat plate portion 34 arranged in a state where both surfaces are parallel to the horizontal direction, and a standing portion 35 erected from the flat plate portion 34, It has. The flat plate portion 34, that is, the base portion 30 is overlaid on the slide base 49 and attached to the slide base 49. For this reason, the base member 50 is provided movably along the left-right direction in FIG. In addition, the longitudinal direction of the flat plate portion 34 is parallel to the left-right direction in FIG.

  The standing portion 35 is erected from one end of the flat plate portion 34 in the left-right direction in FIG. The standing portion 35 includes a pair of standing columns 36 standing from both ends in the width direction X of the flat plate portion 34 and a connecting column connecting the end portions of these standing columns 36 on the side away from the flat plate portion 34. 37, and is formed in a frame shape.

  The imaging lens system 31 includes at least two optical units 38. The optical units 38 are separate from each other. The optical unit 38 includes a lens barrel 39 and a lens group 40 accommodated in the lens barrel 39.

  As shown in FIGS. 1 to 5 and 7, the lens barrel 39 is made of synthetic resin and is molded by a known injection molding or the like. The lens barrel 39 is integrally provided with a large diameter portion 53 and a small diameter portion 54. The large-diameter portion 53 and the small-diameter portion 54 are each formed in a cylindrical shape whose inner and outer diameters are constant in the axial direction. The small diameter portion 54 is connected to the end of the large diameter portion 53 and has a smaller inner and outer diameter than the large diameter portion 53. The large-diameter portion 53 and the small-diameter portion 54 are each formed in an axially symmetric shape with respect to the axis. Further, the large diameter portion 53 and the small diameter portion 54 are provided coaxially.

  At least one lens group 40 is press-fitted into the lens barrel 39. In the illustrated example, two lens groups 40 are provided in one lens barrel 39. One lens group 40 (hereinafter, indicated by reference numeral 40a) of the two lens groups 40 is accommodated in the large diameter portion 53 as shown in FIGS. 7 and 8, and the other lens group 40 (hereinafter, reference numeral). 40b) is accommodated in the small diameter portion 54 as shown in FIGS.

  The optical axes of these lens groups 40a and 40b are arranged on the same line. That is, the lens groups 40a and 40b are provided coaxially with each other. The optical axes of the lens groups 40a and 40b are arranged on the same line as the large diameter portion 53 and the small diameter portion 54, that is, the axis of the lens barrel 39 described above. That is, the lens groups 40a and 40b and the large diameter portion 53 and the small diameter portion 54, that is, the lens barrel 39 are provided coaxially with each other.

  Further, the two optical units 38 are arranged such that the optical axes are located on the same straight line with the small diameter portions 54 facing each other. The large-diameter portion 53 of one optical unit 38 on the left side in FIG. 3 and FIG. 4 (hereinafter, indicated by reference numeral 38a) is opposed to the third mirror 15 in FIG. The large-diameter portion 53 of the other optical unit 38 on the right side in FIGS. 3 and 4 (hereinafter, indicated by reference numeral 38 b) is opposed to the image sensor 32.

  In the illustrated example, the lens group 40 a in the large-diameter portion 53 of one optical unit 38 a facing the third mirror 15 among the lens groups 40 a and 40 b of the two optical units 38 a and 38 b is the most of the image sensor 32. This affects the image formed by the line-type photoelectric conversion element 42 described later. The fact that the image formed by the line photoelectric conversion element 42 of the image sensor 32 is likely to be affected is that the image sensor is caused by the movement of the lens groups 40a and 40b in the aforementioned directions X, Y, Z, α, β, and γ. It shows that the influence on the image formed by the 32 line type photoelectric conversion elements 42 is great.

  An intermediate holding member 33 is attached to the outer peripheral surface of the large diameter portion 53 of the lens barrel 39. That is, the optical units 38 a and 38 b are attached to the flat plate portion 34 of the base member 50 via the intermediate holding member 33. Two intermediate holding members 33 are attached to each optical unit 38a, 38b, that is, the lens barrel 39. The two intermediate holding members 33 position the lens barrel 39 between each other along the width direction X.

  In the present embodiment, the intermediate holding member 33 attached to the lens barrel 39 has a lens group 40a accommodated in the large-diameter portion 53 described above along a direction orthogonal to the optical axis, as shown in FIG. It is arranged in parallel with the center of gravity CG1. In FIG. 8, one optical unit 38a is shown as a representative. As described above, in the present embodiment, the intermediate holding member 33 attached to the lens barrel 39 includes the one lens group 40a that most influences the image formed by the line photoelectric conversion element 42 of the image sensor 32 and the light. It is arranged at a position arranged along the direction orthogonal to the axis O.

  The imaging lens system 31, that is, the lens groups 40 a and 40 b configured as described above forms a reflected image from the document 9 on the line type photoelectric conversion element 42 of the image sensor 32.

  The image sensor 32 includes a package 41 and a line type photoelectric conversion element 42 as a photoelectric conversion element. The package 41 includes, for example, a base 43 made of ceramics, a wind frame 44 made of ceramics, and a sealing glass 45. The base 43 is formed in a flat plate shape, and the line type photoelectric conversion element 42 is attached on the surface. The window frame 44 is formed in a frame shape, and is fixed to the base 43 with an adhesive so as to overlap the outer edge portion of the base 43.

  The sealing glass 45 is formed in a flat plate shape and has an outer edge portion overlapped with the window frame 44 and is fixed to the window frame 44 with an adhesive. The package 41 described above covers the line-type photoelectric conversion element 42 with the base 43, the window frame 44, and the sealing glass 45. The package 41 is attached to the printed wiring board 46 or the like.

  The line-type photoelectric conversion element 42 includes a PD (Photo Diode) that is a photoelectric conversion element and a CCD (Charge Coupled Device) that is a charge transport element arranged in a straight line. The longitudinal direction of the line-type photoelectric conversion element 42 is parallel to the main scanning direction.

  Further, the image sensor 32 described above includes electrodes and lead wires provided in the package 41 for electrically connecting the conductor pattern of the printed wiring board 46 and the electrodes of the line photoelectric conversion element 42 described above. It has. Further, in the image sensor 32 described above, the sealing glass 45 passes through the inner side of the standing portion 35 and faces the imaging lens system 31, and then is attached to the standing portion 35 of the base portion 30 via the intermediate holding member 33. It is attached.

  The intermediate holding member 33 is made of, for example, a synthetic resin that transmits transparent light, and integrally includes a first mounting portion 47 and a second mounting portion 48. The first attachment portion 47 and the second attachment portion 48 are each formed in a flat plate shape. A second attachment portion 48 is erected from the edge of the first attachment portion 47. In the illustrated example, the angle formed by the first mounting portion 47 and the second mounting portion 48 is 90 degrees.

  In the intermediate holding member 33, the first attachment portion 47 is overlaid on the base member 50 of the base portion 30, and the second attachment portion 48 is overlaid on the lens barrel 39 and the package 41 of the image sensor 32. A photo-curing adhesive that cures when irradiated with light such as ultraviolet rays is filled between 48 and the base member 50, the lens barrel 39, and the package 41 of the image sensor 32. The tube 39, that is, the imaging lens system 31 and the package 41, that is, the image sensor 32 are attached. When attached to the base member 50, the optical axis O of the imaging lens system 31 and the image sensor 32 (indicated by the alternate long and short dash line in FIG. 2) is located on the same line.

  In addition, a through hole 55 is provided in the base member 50 of the image reading unit 16 described above. Of course, the through hole 55 penetrates the base member 50. The planar shape of the through-hole 55 is formed to be larger than the planar shape of the imaging lens system 31 in which the two optical units 38a and 38b are combined. The through hole 55 is provided at a position overlapping the two optical units 38 a and 38 b of the base member 50, that is, the imaging lens system 31.

  In the present embodiment, as shown in FIG. 4, the two optical units 38 a and 38 b, that is, the imaging lens system 31 are positioned in the above-described through hole 55 in the plan view of the image reading unit 16. Note that the plan view indicates a state in which the image reading unit 16 is viewed from the thickness direction Y. Further, as shown in FIG. 6, the large-diameter portion 53 of the optical units 38 a and 38 b, that is, a part of the imaging lens system 31 is passed (arranged) in the through hole 55. Further, the optical units 38 a and 38 b are attached to the base member 50 via the intermediate holding member 33 described above.

  As described above, in the present embodiment, the intermediate holding member 33 supports the optical unit 38a, 38b, that is, the lens barrel 39 on the base member 50 in a state where the intermediate holding member 33 is spaced from the inner edge of the through hole 55, ie, the base member 50. is doing. Therefore, before the optical units 38a and 38b are fixed to the intermediate holding member 33, the relative positions of the optical units 38a and 38b with the base member 50 are changed along the above-described directions X, Y, Z, α, β, and γ. Is possible.

  Further, the through hole 55 is provided with a narrow portion 56, a wide portion 57, and a narrow portion 56 in order along the depth direction Z. The narrow portion 56, the wide portion 57, and the narrow portion 56 are each formed in a quadrangular planar shape and communicate with each other. The width of the narrow portion 56 in the width direction X is slightly larger than the outer diameter of the large diameter portion 53 described above. The narrow portion 56 is disposed between the two intermediate holding members 33 of each of the optical units 38a and 38b along the width direction X described above. In the plan view, the narrow portion 56 has a large-diameter portion 53 disposed inside. The width in the width direction X of the wide portion 57 is larger than the width in the width direction X of the narrow portion 56 described above. The wide portion 57 is disposed between the intermediate holding members 33 of the two optical units 38a and 38b along the depth direction Z described above. In the plan view, the wide portion 57 has a small-diameter portion 54 disposed inside.

  The image reading unit 16 having the above-described configuration forms an image of the reflected image from the document 9 guided by the mirrors 13, 14, 15 on the line type photoelectric conversion element 42 of the image sensor 32 by the imaging lens system 31. The image reading unit 16 converts the optical signal into an electric signal by the line photoelectric conversion element 42 and outputs the electric signal to the image processing unit.

  The image reading unit 16 described above is assembled by the assembling apparatus 60 shown in FIGS. As shown in FIGS. 9 and 10, the assembling apparatus 60 includes an apparatus main body (not shown), a base holding portion 61 as a base member holding means, a sensor positioning unit 62 as a sensor positioning means, and two optical positioning means. Two optical positioning units 63a and 63b, a reference light source unit 64, and a control device (not shown) as control means are provided.

  The device body is installed on a factory floor. The base holding part 61 includes a pair of holding members 65. The holding members 65 are attached to the apparatus main body or the like, and are arranged at intervals along the width direction X described above. Each holding pin 65 has a positioning pin 66 protruding upward. The positioning pin 66 enters the positioning hole 52. The base holding portion 61 positions the slide base 49, that is, the base member 50 in a state where the positioning pin 66 enters the positioning hole 52 and the slide base 49 is spanned between the pair of holding members 65.

  The sensor positioning unit 62 includes a chuck cylinder 67 and a moving device 68. The chuck cylinder 67 includes a cylinder body 69 and a pair of chucks 70. The pair of chucks 70 protrude from the cylinder body 69. The pair of chucks 70 are formed in a rod shape and are arranged in parallel to each other. The longitudinal direction of the pair of chucks 70 is parallel to both the horizontal direction and the depth direction Z described above. The pair of chucks 70 are brought into contact with and separated from each other by the cylinder body 69. The pair of chucks 70 approaches and sandwiches the image sensor 32 between each other.

  The moving device 68 is attached to both the device main body and the cylinder main body 69 of the chuck cylinder 67 described above. The moving device 68 moves the above-described chuck cylinder 67, that is, the image sensor 32 along each of the above-described directions X, Y, Z, α, β, and γ.

  The sensor positioning unit 62 described above sandwiches the image sensor 32 between a pair of chucks 70 of the chuck cylinder 67, and the image sensor 32 is moved by the moving device 68 in each of the directions X, Y, Z, α, β, γ described above. Move along. The sensor positioning unit 62 described above positions the image sensor 32 at a predetermined position.

  Each of the two optical positioning units 63 a and 63 b includes a chuck portion 71 and a moving device 72. As shown in FIG. 11, the chuck portion 71 includes a chuck main body 73 formed in a rod shape, a sandwich piece 74, and the like. The chuck body 73 is arranged such that its longitudinal direction is parallel to both the vertical direction and the thickness direction Y described above. A V groove 76 is provided on the upper surface 75 of the chuck body 73. The V groove 76 is formed in a concave shape from the upper surface of the chuck body 73 and has a V-shaped cross section. The cross-sectional shape of the V groove 76 is constant along the depth direction. The V groove 76 positions the small diameter portion 54 of the lens barrel 39 of the optical units 38a and 38b on the inner side.

  The sandwiching piece 74 is formed in a plate shape, and is attached to the upper surface 75 of the chuck body 73 by a screw 77 or the like so as to be able to contact and separate. Further, the sandwiching piece 74 is urged toward the upper surface 75 of the chuck main body 73 described above by a coil spring 78 or the like. The sandwiching piece 74 sandwiches the small diameter portion 54 of the lens barrel 39 of the optical unit 38a, 38b with the V groove 76. The moving device 72 is attached to both the device main body and the chuck main body 73 described above. The moving device 72 moves the above-described chuck body 73, that is, the optical units 38a and 38b along each of the aforementioned directions X, Y, Z, α, β, and γ.

  The optical positioning units 63a and 63b described above sandwich the optical units 38a and 38b between the V groove 76 of the chuck body 73 and the sandwiching piece 74, and the optical units 38a and 38b are moved by the moving device 72 in the directions X and X described above. It moves along each of Y, Z, α, β, and γ. The optical positioning units 63a and 63b described above position the optical units 38a and 38b at predetermined positions.

  The reference light source unit 64 is attached to the apparatus main body. As shown in FIG. 10, the reference light source unit 64 includes a reference chart sheet 79 and a light source 80 including a halogen lamp. The reference light source unit 64 emits light from the light source 80 that has passed through the reference chart sheet 79 toward the image sensor 32 sandwiched between the pair of chucks 70 of the sensor positioning unit 62.

  The control device is a computer including a known RAM, ROM, CPU, and the like. The control device is connected to the above-described sensor positioning unit 62, the two optical positioning units 63a and 63b, and the reference light source unit 64, controls these operations, and controls the entire assembly device 60.

  The image reading unit 16 is assembled as follows using the assembly device 60 described above. First, the base member 50 attached to the slide base 49, that is, the base member 50 is positioned on the base holding portion 61. Further, the image sensor 32 is sandwiched between the pair of chucks 70 of the sensor positioning unit 62, and the optical units 38a and 38b are sandwiched between the V grooves 76 and the sandwiching pieces 74 of the optical positioning units 63a and 63b. Further, the reference chart sheet 79 is attached to the reference light source unit 64.

  First, the sensor positioning unit 62 and the optical positioning units 63a and 63b are positioned so that the aforementioned image sensor 32 and the optical units 38a and 38b have a predetermined positional relationship as shown in FIG. To do.

  Then, light is emitted from the light source 80 of the reference light source unit 64, and this light is received by the line-type photoelectric conversion element 42 of the image sensor 32 through the lens groups 40a and 40b of the optical units 38a and 38b. The moving device 68 moves the image sensor 32 in the above-described directions X, Y, Z, α, β, γ so that a desired signal can be obtained from the line-type photoelectric conversion element 42. The moving device 68 is stopped and the image sensor 32 is positioned at a position where a desired signal can be obtained from the line-type photoelectric conversion element 42.

  Thereafter, light from the light source of the reference light source unit 64 is received by the line-type photoelectric conversion element 42 of the image sensor 32 through the lens groups 40a and 40b of the two optical units 38a and 38b. The moving device 72 moves the optical units 38a and 38b in the aforementioned directions X, Y, Z, α, β, and γ so that a desired signal can be obtained from the line-type photoelectric conversion element 42. At this time, the chuck body 73 of the optical positioning unit 63b is moved in the above-described directions X, Y, Z, α, β, γ within the wide portion 57 of the through hole 55. At a position where a desired signal can be obtained from the line-type photoelectric conversion element 42, the moving device 72 is stopped and the optical units 38a and 38b are positioned. In this way, the positions of the optical units 38a and 38b are finely adjusted.

  Thus, the two optical units 38a and 38b and the image sensor 32 are positioned with respect to the base member 50 as shown in FIG. Then, the intermediate holding member 33 is positioned at a predetermined position, between the intermediate holding member 33 and the base member 50, between the intermediate holding member 33 and the optical units 38a and 38b, the intermediate holding member 33 and the image sensor 32, and In between, a photo-curable adhesive is filled. Thereafter, the adhesive is cured, and the two optical units 38 a and 38 b and the image sensor 32 are fixed to the base member 50. And the printed wiring board 46 is attached and the image reading unit 16 of the structure mentioned above is obtained.

  In the image forming apparatus 1 described above, the automatic document feeder 3 automatically feeds the document 9 onto the contact glass 10 of the scanner device 4 and automatically ejects the document 9 that has been read. In the image forming apparatus 1, the scanner device 4 irradiates the document 9 set on the contact glass 10 with light, and reads a reflected image from the document 9 by a line type photoelectric conversion element 42 as a photoelectric conversion element.

  In the image forming apparatus 1, the writing unit 6 forms an image on the photosensitive drum 26 based on the image signal of the reflected image from the original 9 photoelectrically converted by the scanner device 4, and feeds the paper from the paper feeding unit 5. The image is transferred and fixed on the transferred paper 21. The image forming apparatus 1 discharges the transfer paper 21 that has been fixed to the outside of the apparatus main body 2.

  According to the present embodiment, the intermediate holding member 33 supports the lens barrel 39 at a distance from the base member 50, so that each lens barrel 39 is directed to the base member 50 in the directions X, Y, Z described above. , Α, β, γ can move in all directions (position can be adjusted).

  In this way, with a simple configuration in which the lens barrel 39 is provided with a plurality of separate optical units 38a and 38b, adjustment of the rotation direction of the lens barrel 39 and adjustment of the distance between the lens barrels 39 are independent of each other. Can be done. Therefore, necessary lens characteristics can be obtained easily and reliably, and a high-performance image reading unit 16 and scanner device 4 can be obtained. Therefore, a high-quality read image can be obtained, a high-quality electrostatic latent image can be formed, and an image forming apparatus 1 that can form a high-quality copy image can be obtained. Furthermore, since necessary lens characteristics can be obtained easily and reliably, the number of assembling steps for the image reading unit 16 can be reduced.

  Further, since the through hole 55 is provided in the base member 50, a space in which the optical positioning units 63a, 63b and the like can grip the lens barrel 39 of the optical unit 38a, 38b in the through hole 55 can be secured. Therefore, the position adjustment and fixing of the lens barrel 39 can be easily performed, so that the number of assembling steps can be reduced.

  Further, by providing the through hole 55, the lens barrel 39 can be easily adjusted in position and fixed, so that the shape of the base member 50 can be simplified. Therefore, the cost of parts can be reduced.

  Since the planar shape of the through-hole 55 is formed larger than the planar shape of the imaging lens system 31, a space in which the lens barrel 39 can be gripped in the through-hole 55 can be reliably ensured. Therefore, the assembly man-hour can be reduced.

  Since a part of the imaging lens system 31 is accommodated in the through-hole 55, the amount of projection of the imaging lens system 31 from the base member 50 can be suppressed, and the thickness of the image reading unit 16 in the thickness direction Y can be suppressed. . Therefore, the image reading unit 16 can be downsized.

  Since the through hole 55 includes the wide portion 57 wider than the narrow portion 56, a space in which the lens barrel 39 of the optical units 38 a and 38 b can be gripped can be secured in the wide portion 57. Therefore, the lens barrel 39 can be easily adjusted and fixed, so that the number of assembling steps can be reduced.

  Since the lens barrel 39 includes a small diameter portion 54 that is thinner than the large diameter portion 53, the lens barrel 39 can be easily grasped by grasping the small diameter portion 54, and the lens barrel 39 can be adjusted in position. It is possible to prevent the optical positioning units 63a, 63b and the like that hold the lens barrel 39 from interfering with the base member 50. Therefore, the position adjustment of the optical unit 38a, 38b, that is, the lens barrel 39 can be reliably performed.

  Since the small diameter portion 54 of the lens barrel 39 is positioned within the wide portion 57 of the through hole 55, the small diameter portion 54 can be reliably grasped, and the lens barrel 39 can be adjusted when adjusting the position of the lens barrel 39. It is possible to reliably prevent the optical positioning units 63a, 63b and the like that grip the base member 50 from interfering with each other. Therefore, the position adjustment of the optical unit 38a, 38b, that is, the lens barrel 39 can be reliably performed.

  Since the large diameter portion 53 and the small diameter portion 54 are coaxial, the lens group 40 a inserted into the large diameter portion 53 and the lens group 40 b inserted into the small diameter portion 54 are coaxial. Therefore, the necessary lens characteristics can be obtained easily and reliably, and the number of assembling steps for the image reading unit 16 can be reduced.

  Since the lens barrel 39 and the lens groups 40a and 40b are coaxial with each other, the optical axis of the lens group 40a and 40b is the center of rotation of the lens barrel 39 when the lens barrel 39 is rotated to adjust the position. It is possible to prevent rotation about the axis as a center. Therefore, the position adjustment in the rotation direction of the lens barrel 39 and the lens groups 40a and 40b, that is, the optical unit 38 can be easily performed, and the number of assembling steps of the image reading unit 16 can be reduced.

  Further, since the lens barrel 39 is formed symmetrically with respect to the axis, even if the lens groups 40a and 40b are press-fitted into the lens barrel 39, the lens barrel 39 is uniformly deformed in the circumferential direction. Become. For this reason, it can prevent that the optical axis of lens group 40a, 40b and the axial center of the lens-barrel 39 shift, and can keep these coaxially reliably. Therefore, even if the lens barrel 39 is rotated around the axis, the optical axes of the lens groups 40a and 40b can be more reliably prevented from rotating away from the target axis. Therefore, the position adjustment in the rotation direction of the lens barrel 39 and the lens groups 40a and 40b, that is, the optical unit 38 can be easily performed, and the number of assembling steps of the image reading unit 16 can be reduced.

  An intermediate holding member 33 is disposed at a position in the lens groups 40a and 40b that is arranged side by side along the direction orthogonal to the optical axis O and the lens groups 40a and 40b in which the positional deviation most affects the image characteristics. Thus, when the lens barrel 39, that is, the optical unit 38 vibrates, the vibration of the lens group 40a that most affects the image characteristics can be suppressed. Therefore, it is possible to provide the image reading unit 16 whose image characteristics are not easily affected by vibration.

  In the present invention, as shown in FIG. 12, the outer diameter may be gradually reduced as the small diameter portion 54 is separated from the large diameter portion 53. Also in the lens barrel 39 shown in FIG. 12, the inner diameter of the small diameter portion 54 is constant in the axial direction. In this case, since the small diameter portion 54 gradually becomes thinner as it moves away from the large diameter portion 53, the lens group 40b can be easily press-fitted into the small diameter portion 54.

  Since the small diameter portion 54 is tapered, the lens groups 40a and 40b and the chuck 70 of the assembling apparatus 60 can be reliably positioned, and the positioning accuracy of the lens groups 40a and 40b can be improved. Therefore, it becomes easy to adjust the lens groups 40a and 40b, and the number of assembling steps can be reduced.

  Furthermore, in the present invention, as shown in FIG. 13, a plurality of intermediate holding members 33 are arranged side by side along the optical axis of the imaging lens system 31 in the axial center, and the lens mirrors of the respective optical units 38 a and 38 b. These intermediate holding members 33 may be attached to the outer peripheral surface of the tube 39. In FIG. 13, the optical unit 38a is shown as a representative. In this case, since a plurality of intermediate holding members 33 are attached to the lens barrel 39 along the optical axis O, vibrations of the lens barrel 39, that is, the optical units 38a and 38b due to vibration can be reduced. Therefore, it is possible to provide the image reading unit 16 whose image characteristics are not easily affected by vibration.

  Further, as shown in FIG. 14, an intermediate holding member 33 may be attached at a position where the center of gravity CG2 of each of the optical units 38a and 38b is aligned along the direction perpendicular to the optical axis O. In this case, it is possible to provide the image reading unit 16 that can reliably suppress the vibration of the optical unit 38 and whose image characteristics are not easily affected by the vibration. In FIG. 14, the optical unit 38a is shown as a representative.

  Furthermore, in the above-described embodiment, the intermediate holding member 33 is disposed at a position where the lens group 40a near the third mirror 15 of the optical unit 38a near the third mirror 15 and the optical axis O are juxtaposed along the direction perpendicular to the optical axis O. It is attached. In the present invention, for example, if three lens groups 40 are provided and the ease of affecting the characteristics of the image obtained by the image sensor 32 is arranged in the order of large, medium, and small from the third mirror 15 side, the third is the third. The intermediate holding member 33 may be attached to a position where the lens group 40 near the mirror 15 and the optical axis O are arranged in parallel.

  Further, if three lens groups 40 are provided and the ease of affecting the characteristics of the image obtained by the image sensor 32 is arranged in the order of small, medium, and large from the third mirror 15 side, it is farthest from the third mirror 15. What is necessary is just to attach the intermediate holding member 33 to the position arranged along the direction orthogonal to the lens group 40 and the optical axis O. In short, in the present invention, it is desirable to attach the intermediate holding member 33 at a position along the direction perpendicular to the optical axis O and the lens group 40 that most easily affects the characteristics of the image obtained by the image sensor 32.

  In the present invention, the optical unit 38 may include only one lens group 40 or three or more lens groups 40. In short, in the present invention, the optical unit 38 only needs to include at least one lens group 40. In the present invention, three or more optical units 38 may be provided. In short, in the present invention, it is sufficient that at least two optical units 38 are provided.

  In the present invention, the through hole 55 may not be provided, and even when the through hole 55 is provided, the through hole 55 may be smaller than the imaging lens system 31, and the imaging lens system 31 is disposed in the through hole 55. It is not necessary to insert a part of. The wide portion 57 may not be provided in the through hole 55. In short, in the present invention, the intermediate holding member 33 may support the lens barrel 39 at a distance from the base member 50. Furthermore, in the present invention, the intermediate holding member 33 may not be attached at a position where the lens group 40 that most easily affects the characteristics of the image obtained by the image sensor 32 and a position along the direction orthogonal to the optical axis O are arranged. .

  In the embodiment described above, the lens barrel 39 of each optical unit 38 includes the large diameter portion 53 and the small diameter portion 54. However, in the present invention, it is sufficient that at least one lens barrel 39 includes the large diameter portion 53 and the small diameter portion 54. In the above-described embodiment, the line type photoelectric conversion element 42 is used. However, in the present invention, of course, a planar photoelectric conversion element may be used.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

It is explanatory drawing which shows the image forming apparatus concerning one embodiment of this invention. FIG. 2 is a perspective view showing an image reading unit of the image forming apparatus shown in FIG. 1. FIG. 3 is a side view of the image reading unit shown in FIG. 2. FIG. 3 is a plan view of the image reading unit shown in FIG. 2. It is sectional drawing which follows the VV line in FIG. It is sectional drawing which follows the VI-VI line in FIG. It is sectional drawing of the optical unit of the image reading unit shown by FIG. It is explanatory drawing which shows the positional relationship of the optical unit shown by FIG. 7, and an intermediate holding member. It is explanatory drawing which shows the assembly apparatus used when assembling the image reading unit shown by FIG. FIG. 10 is an explanatory diagram illustrating a state in which the image sensor and the optical unit are positioned in the assembling apparatus illustrated in FIG. 9. It is a front view which shows the principal part of the chuck | zipper main body of the optical positioning unit of the assembly apparatus shown by FIG. It is sectional drawing which shows the modification of the optical unit shown by FIG. It is explanatory drawing which shows the modification of the positional relationship of the optical unit shown by FIG. 8, and an intermediate | middle holding member. It is explanatory drawing which shows the other modification of the positional relationship of the optical unit and intermediate | middle holding member which were shown by FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 4 Scanner apparatus 9 Document 16 Image reading unit 31 Imaging lens system 33 Intermediate holding member 38, 38a, 38b Optical unit 39 Lens barrel 40, 40a, 40b Lens group 42 Line type photoelectric conversion element (photoelectric conversion element) )
50 Base member 53 Large diameter portion 54 Small diameter portion 55 Through hole 56 Narrow portion 57 Wide portion O Optical axis

Claims (11)

An imaging lens system having at least two lens barrels that house a lens group that forms a reflected image from a document on a photoelectric conversion element;
A base member to which both the photoelectric conversion element and the imaging lens system are attached;
An intermediate holding member attached to both the lens barrel and the base member;
An image reading unit comprising:
The at least one lens barrel is supported by the intermediate holding member in a state of being spaced from the base member, and the intermediate holding member has two surfaces that intersect substantially vertically, and one surface is a base member. The other surface is glued and fixed to the lens barrel ,
A through hole penetrating the base member is provided at a position where the lens barrel of the base member overlaps; and
The through hole is
A narrow portion arranged in parallel with the intermediate holding member along a direction intersecting the optical axis of the imaging lens system,
A wide portion provided in parallel with the intermediate holding member along the optical axis of the imaging lens system, and
An image reading unit characterized in that the width in the direction intersecting the optical axis of the imaging lens system in the wide part is wider than the width in the direction intersecting the optical axis of the imaging lens system in the narrow part. . The image reading unit according to claim 1 , wherein a part of the imaging lens system is inserted into the through hole . The lens barrel includes a large-diameter portion to which the intermediate holding member is attached, and a small-diameter portion that is continuous with the large-diameter portion and has a smaller diameter than the large-diameter portion. Item 3. The image reading unit according to Item 2 . The image reading unit according to claim 3, wherein the small-diameter portion is formed so that the outer diameter gradually decreases as the small-diameter portion moves away from the large-diameter portion . The image reading unit according to claim 3, wherein the small diameter portion is disposed in the wide portion . 6. The image reading unit according to claim 3, wherein the large diameter portion and the small diameter portion are arranged coaxially with each other . 7. The image reading according to claim 1, wherein the lens barrel and a lens group accommodated in the lens barrel are arranged coaxially with each other. unit. At least one lens barrel accommodates two or more of the lens groups;
The intermediate holding member is juxtaposed along a direction perpendicular to the optical axis with a lens group that most affects an image formed by a photoelectric conversion element among two or more lens groups. The image reading unit according to any one of claims 1 to 7 . 9. The intermediate holding member according to claim 1, wherein a plurality of the intermediate holding members are attached to at least one lens barrel along the optical axis of the imaging lens system. image reading unit according to an item or. In a scanner device that reads a reflected image from a document with a photoelectric conversion element,
A scanner device comprising the image reading unit according to claim 1 . An image forming apparatus comprising the scanner device according to claim 10 .

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