JP4525503B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus, and more particularly to a coupling structure of a case that houses a reading unit that reads an image and a cover that covers an opening of the case.

Conventionally, as a coupling structure between a case and a cover of an image reading device, coupling by snap fit is known (Patent Document 1). The coupling | bonding by a snap fit locks the claw provided in either one of a case or a cover to the opening provided in the other of a case or a cover. Compared with screw connection, the snap-fit connection can reduce the size of the connection part consisting of the pawl and opening, so it can be used for designs where the connection part is not thick. Can be miniaturized. Furthermore, since no screws are used, the number of parts can be reduced.
However, due to the gap generated between the claw and the opening constituting the snap fit, play occurs in the case and cover connection. Therefore, when reading a document placed on the platen constituting the cover, there is a problem that the image of the document on the platen cannot be read with high accuracy.

Japanese Unexamined Patent Publication No. 7-121264

  The present invention has been made to solve the above-described problems, and provides an image reading apparatus having a coupling structure that can couple a case and a cover without play with a small number of parts and can be miniaturized. .

(1) An image reading apparatus for achieving the above object includes: a reading unit that reads an image by photoelectric conversion; a case that accommodates the reading unit; and a case that is coupled to the case by a snap fit and a screw; And a cover for covering.
According to the present invention, the cover and the case can be joined without play with a small number of parts by adopting both the snap fit and the screw at appropriate portions as means for joining the case housing the reading unit and the cover. In addition, the image reading apparatus can be downsized.

(2) a claw provided on one of the case or the cover, an opening provided on the other of the case or the cover and locking the inserted claw, and the case or the cover provided with the opening. A partition provided on an inner wall for collecting dust entering from the opening .
According to the present invention, since the partition wall that collects dust entering the case is provided on the inner wall of the cover, it is possible to prevent dust from entering the optical path of the reading unit and causing noise in the read image.

(3) The partition may have a bottom portion formed below the opening, and a wall portion that rises from the bottom portion and is connected to an inner wall of the case or the cover provided with the opening.
According to the present invention, it is accumulated in the bottom of the dust entering from the opening is formed below the opening, preventing the wall portion that rises from the bottom that accumulated dust moves from the bottom to the optical path of the reading unit be able to.

Embodiments of the present invention will be described below based on examples.
First, an image scanner 1 as an embodiment of the image reading apparatus of the present invention will be described.
FIG. 2 is a perspective view showing the external appearance of the image scanner 1. The image scanner 1 is a so-called flat bed type image scanner. The image scanner 1 can read a printed document or a photo placed on the platen 10. In the present embodiment, description will be made as components of a multifunction machine having an image reading function and a printing function. The image reading apparatus may be a single image scanner.

  FIG. 1 is a perspective view showing a state in which the case 14 and the cover 16 of the image scanner 1 are disassembled, and FIG. 3 is a schematic diagram showing the internal structure of the image scanner 1. The housing of the image scanner 1 is composed of a case 14 that is formed in a box shape with an opening formed above, and a cover 16 that covers the opening of the case 14. In this embodiment, “upward” means the upper side in the vertical direction. The cover 16 includes a rectangular platen 10 formed of a transparent plate such as a glass plate and a platen frame 18 surrounding the platen 10, and the platen 10 is fixed to the platen frame 18.

The case 14 houses a carriage 20, a belt (not shown) that pulls the carriage 20, a motor (not shown) that rotates the belt, and the like.
The carriage 20 includes an illumination unit 26, a refractive index dispersion lens array 28, and a linear image sensor 30. The linear image sensor 30 is a contact image sensor mounted on a printed circuit board (not shown), and includes a plurality of light receiving elements, MOS transistor switches, and the like arranged in a straight line. The illumination unit 26 illuminates the vicinity of the scanning line of the document 12. The refractive index dispersion lens array 28 forms a reflected light image on the main scanning line of the illuminated original 12 on the light receiving surface of the linear image sensor 30. The linear image sensor 30 scans an optical image to be formed and outputs an electrical signal correlated with the density of the optical image. The electrical signal output from the linear image sensor 30 is converted into digital image data by an analog front end unit and a digital image processing unit (not shown). The image sensor may be a close contact type or a lens reduction type.
The guide 24 for guiding the carriage 20 is formed integrally with the bottom portion of the case 14. The carriage 20 is slidably supported by the guide 24 and is locked to the belt. When the pulley is driven by the motor, the carriage 20 slides along the guide 24 in the sub-scanning direction.

  Next, the connection by the screw in the vicinity of the guide 24 of the case 14 and the cover 16 will be described. Bosses 38 are formed in the vicinity of both ends of the guide 24 of the case 14. To join the case 14 and the cover 16, a screw 46 is screwed into the female screw 42 of the cover 16 from the screw hole 40 of the boss 38 of the case 14. FIG. 4 is a cross-sectional view of the vicinity of the boss 38. The boss 38 protrudes upward from the case 14 and includes a screw hole 40. Further, the platen frame 18 of the cover 16 is formed with a boss 44 that protrudes downward at a position corresponding to the boss 38 and includes a female screw 42. The case 14 and the cover 16 are joined by screwing a screw 46 from the screw hole 40 of the boss 38 into the female screw 42 of the platen frame 18 to join the case 14 and the cover 16. In this embodiment, “downward” refers to the lower side in the vertical direction. Thus, by tightening the vicinity of both ends of the guide 24 with screws and fixing the cover 16 to the case 14, the tolerance in the vicinity of the guide 24 can be reduced. Therefore, an image can be read with high accuracy by the linear image sensor 30 mounted on the carriage 20 that is in sliding contact with the guide 24.

  The housing of the image scanner 1 is slidably coupled by a hinge above the housing of the printing unit (not shown). As shown in FIG. 5, in the vicinity of the hinge 48, the case 14, the cover 16, and the hinge 48 are coupled by screws. Specifically, the center of the screw hole 50 formed in the case 14 and the screw hole 52 formed in the hinge 48 are aligned, and the screw 54 is passed through and screwed into the female screw 56 formed in the platen frame 18. In this manner, the case 14 and the cover 16 are coupled with screws in the vicinity of the hinge 48 serving as a movable portion, thereby preventing rattling that occurs when the image scanner 1 swings with respect to the casing of the printing portion. Can do.

Next, the coupling between the cover 16 and the case 14 by snap fitting will be described.
6A is a cross-sectional view taken along the line II of FIG.
The snap fit in this embodiment locks the pawl 62 in the opening 58. The opening 58 is a hole penetrating the side wall 60 of the case 14 formed in the vicinity of the upper end of the case 14 formed in a box shape. The pawl 62 includes a support portion 64 that extends downward from the platen frame 18 and a protrusion 66 that protrudes outward from the support portion 64. When the cover 16 covers the case 14, the projection 66 of the pawl 62 is formed in a position where the pawl 62 fits into the opening 58 and the pawl 62 is locked to the opening 58. Thus, in the coupling by snap fitting, the space necessary for the coupling structure is the length of the support portion 64 of the pawl 62 in the vertical direction (h in the figure) and the thickness of the support portion 64 in the horizontal direction ( Since it is d) in the illustrated example, it is smaller than the case of using a screw, and is useful when the thickness of the connecting portion cannot be increased in terms of design or molding process. For example, the case 14 and the cover 16 are joined by snap fitting at the end in the sub-scanning direction, thereby reducing the difference between the volume of the space in which the carriage 20 moves and the volume of the image scanner 1 and downsizing the entire product. can do. Moreover, the number of parts can also be reduced by not using a screw.

  As described above, in the connection between the case 14 and the cover 16 of the image scanner 1, screws are used in places such as the vicinity of the guide 24 and the vicinity of the hinge 48 that require the rigidity of the connection, and the case 14 and the cover 16 are connected. By using a snap fit at a portion where the coupling rigidity is not so required, such as an end portion, high reading accuracy can be achieved while supporting various designs.

Next, the partition for collecting dust entering from the snap-fit opening 58 will be described.
FIG. 7 is a cross-sectional view taken along the line IV-IV in FIG. The partition wall 68 includes a bottom portion 70 of the opening 58 and a wall portion 72 that rises from the bottom portion 70 of the opening 58. The wall portion 72 is formed so as to surround the claw 62 locked to the opening 58 from the inside of the case 14, and is connected to the inner wall of the side wall 60 of the case 14. The bottom 70 and the wall 72 are connected without a gap. Thus, since the opening 58 is surrounded by the partition wall 68, the dust that has entered from the opening 58 is prevented from entering the inside of the case 14 by the partition wall 68, and the dust accumulated in the bottom portion 70 is also protected by the wall portion 72. 14 does not enter the inside.

FIG. 6B is a cross-sectional view taken along line VV in FIG. A groove 78 composed of a horizontal bottom 74 and a wall 76 rising from the bottom is formed at the upper end of the side wall 60 of the case 14, and a protrusion 80 corresponding to the groove 78 is formed at the end of the platen frame 18. Thus, by providing the wall portion 76 and the bottom portion 74 at the upper end of the side wall 60 of the case 14, it is possible to prevent dust from entering from the contact points of the end portions of the case 14 and the cover 16 even at the upper end of the side wall 60 of the case 14. This can be prevented by the part 76.
Therefore, according to the present invention, it is possible to prevent dust from entering the optical path and causing noise in the read image.

The perspective view which concerns on one Example of this invention. The perspective view which concerns on one Example of this invention. The schematic diagram which concerns on one Example of this invention. Sectional drawing which concerns on one Example of this invention. Sectional drawing which concerns on one Example of this invention. Sectional drawing which concerns on one Example of this invention. Sectional drawing which concerns on one Example of this invention.

Explanation of symbols

1: image scanner (image reading device), 10: platen (cover), 14: case, 16: cover, 18: platen frame (cover), 26: illumination unit (reading unit), 28: refractive index dispersion lens array (Reading unit), 30: linear image sensor (reading unit), 42: female screw, 46: screw, 58: opening (snap fit), 62: pawl, 68: partition, 70: bottom, 72: wall

Claims (2)

A reading unit for reading an image by photoelectric conversion;
A case for accommodating the reading unit;
A cover that is coupled to the case by a snap fit and a screw and covers an opening of the case;
And a claw provided before Symbol cover,
Provided in the case, the opening for locking the pawl inserted,
A partition that is provided on an inner wall of the case where the opening is provided, and that collects dust that enters the optical path from the opening;
An image reading apparatus comprising: The image reading apparatus according to claim 1, wherein the partition wall includes a bottom portion formed below the opening and a wall portion that rises from the bottom portion and is connected to an inner wall of the case where the opening is provided.

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