JP2013062629A - Original reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a foreign matter from intruding into a case without causing a deformation, such as bending, of the case and without increasing the number of components, on an original reading device in which a platen glass is mounted at an opening part formed on an upper surface of the case.SOLUTION: A support part 22, which is one step higher than the other parts, is continuously formed in a circumference of an opening part 20 of a case 2. A platen glass 11 is supported by a support part 22, while the platen glass 11 and the support part 22 are airtightly brought into contact. From a viewpoint of reliably preventing a foreign matter from intruding into the case 2, it is preferable that an outer peripheral end 22a of the support part 22 is positioned inner than an outer peripheral end 11a of the platen glass 11.

Description

  The present invention relates to a document reading apparatus used for a copying machine, a facsimile, a printer, and an image forming apparatus having a combination of these functions.

  The original reading device optically scans and reads an original. Specifically, an original is placed on a platen glass and irradiated with light, and the reflected light or transmitted light is optically processed and converted into a digital signal by a photoelectric conversion element such as a CCD to obtain image data. To do. Here, when a foreign substance such as dust adheres to an optical component such as a mirror or a lens in the document reading apparatus, the foreign object is also read as an image, resulting in a deterioration in image quality.

  Conventionally, the platen glass is attached to the device case by, for example, providing projections at the four corners of the case to support the platen glass in order to determine the height position, but between the platen glass and the case. There was a case where a foreign matter entered the housing from here. In addition, it is conceivable that the platen glass is directly attached to the opening formed in the housing. However, when the thickness of the housing material is reduced, the strength of the housing is reduced, the housing is bent, and the platen glass and the housing are There is a gap between them, and foreign matter enters from the gap in the same manner as described above.

  Therefore, for example, Patent Document 1 proposes a configuration in which a seal member is interposed between the platen glass and the housing to prevent foreign matter from entering.

Japanese Unexamined Patent Publication No. 7-287438

  However, in the proposed configuration, since the sealing member must be interposed over the entire outer periphery of the platen glass, the assembling work becomes complicated and the working efficiency is lowered. Also, the number of parts increases.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to prevent deformation such as bending in an original reading apparatus in which a platen glass is attached to an opening formed on the upper surface of the casing. An object of the present invention is to prevent foreign matter from entering the housing without causing it to occur on the body and without increasing the number of parts.

  The document reading apparatus according to the present invention that achieves the above object seals at least a part of the opening of the housing, the housing having the opening formed on the upper surface, the optical component attached in the housing, and the housing. A platen glass on which a document is placed, and the platen glass is supported by a support portion that is formed continuously from the periphery of the opening and that is one step higher than the other portion of the upper surface of the housing; The platen glass and the support portion are in airtight contact with each other.

  Here, a slit glass for reading the document conveyed by the automatic document conveying device may be further provided, and the opening of the housing may be sealed with the platen glass and the slit glass.

  In addition, from the viewpoint of more reliably preventing the entry of foreign matter into the housing, it is preferable that the outer peripheral end of the support portion be positioned inside the outer peripheral end of the platen glass.

  Further, a rising portion for positioning the platen glass may be cut and formed on the support portion, and the opening after the cut and raised may be closed with an elastic member from the inside of the casing.

  In the document reading apparatus according to the present invention, the platen glass is supported by the support portion that is continuously formed around the periphery of the opening on the top surface of the housing and is one step higher than the other portions on the top surface of the housing. Since the platen glass and the support portion are in airtight contact with each other, the intrusion of foreign matter into the housing can be prevented without using a seal member or the like.

1 is a perspective view showing an example of a document reading apparatus according to the present invention. FIG. 2 is a vertical sectional view showing a schematic configuration of the document reading apparatus shown in FIG. 1. The elements on larger scale of the A section of FIG. The partial vertical sectional view which shows the attachment state to the support part of platen glass. FIG. 6 is a perspective view showing another example of a document reading apparatus according to the present invention. FIG. 6 is a vertical cross-sectional view of both ends in the longitudinal direction of the slit glass of the document reading apparatus of FIG. 5. FIG. 6 is a vertical sectional view of a central portion in the longitudinal direction of the slit glass of the document reading apparatus in FIG. 5. The fragmentary perspective view of the support part in which the standing part was formed.

  Hereinafter, the document reading apparatus according to the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to these embodiments.

FIG. 1 is a perspective view showing an example of a document reading apparatus according to the present invention, and FIG. 2 is a vertical sectional view showing a schematic configuration. In the document reading apparatus R ₁ shown in FIG. 1, the platen glass 11 is placed in a rectangular opening 20 formed on the upper surface of the housing 2. Inside the housing 2 are provided travel units (optical components) 12a and 12b, which will be described later, and an image sensor (optical component) 13 for converting light such as a CCD into an electrical signal.

  As shown in FIG. 2, a first traveling unit 12 a and a second traveling unit 12 b are provided below the platen glass 11. The first traveling unit 12a and the second traveling unit 12b are moved in the horizontal direction by the power from the motor 15 by a drive transmission mechanism and a traveling rail (not shown).

  The first traveling unit 12a includes a light source 121, a reflecting plate 122, and a mirror 123. The first traveling unit 12a emits light from the light source 121 to the document 10 placed on the platen glass 11, and the reflected light is mirrored. 123 to send to the second traveling unit 12b. This is to enhance the effect of efficiently irradiating the surface of the original with the light from the light source 121 by the reflection plate 122. The first traveling unit 12a moves from the left end to the right end of the document 10, and continuously transmits reflected light from the document to the second traveling unit 12b.

  The second traveling unit 12b includes a mirror 124 and a mirror 125, and sends the light transmitted from the first traveling unit 12a to the image sensor 13 such as a CCD through the lens 12c. The second traveling unit 12b moves in synchronization with the first traveling unit 12a, but its moving speed is half that of the first traveling unit 12a. Due to the movement of the second traveling unit 12b, the distance from the image surface of the document 10 to the lens 12c becomes the same at any position on the document 10. As a result, the focal point is in any position on the document 10.

  Then, the light condensed by the lens 12c is irradiated to the image sensor 13 and converted into an electric signal. In this example, the image of the document is converted into an electrical signal by the image sensor 13, but a photoconductor is arranged outside the document reader instead of the image sensor 13, and is uniformly charged. An electrostatic latent image identical to the original image may be formed on the surface of the photosensitive member by irradiating the surface with light that has passed through the lens 12c and performing exposure. In this case, the light passing through the lens 12c is irradiated to the photosensitive member through a separate window glass.

  FIG. 3 shows an enlarged perspective view of a portion A in FIG. As shown in FIGS. 1 and 3, a support portion 22 that is one step higher than the other portions of the upper surface of the housing is continuously formed on the periphery of the opening 20 formed on the upper surface of the housing 2. Yes.

  As shown in FIG. 4, the support portion 22 is formed higher than the reference surface 21 of the housing 2 by a height H. The platen glass 11 is placed on the upper surface of the support portion 22, and the platen glass 11 is supported by the support portion 22. In this way, by making the contact surface between the platen glass 11 and the housing 2 one step higher than the reference surface 21, foreign matters such as dust and dust accumulated on the upper surface of the housing 2 enter the housing 2. Is suppressed. Further, the strength of the housing 2 with respect to the bending moment is improved, and the housing 2 is not deformed such as bending by supporting the platen glass 11. Although there is no limitation in particular in the height H, generally the range of 0.5 mm-5 mm is preferable. In addition, the inclination angle from the reference surface 21 to the support portion 22 may be appropriately determined in consideration of workability and the like. However, as the inclination angle is made steeper, the effect of suppressing the entry of foreign matter into the housing 2 becomes higher. .

  Further, the outer peripheral end 22 a of the support portion 22 is positioned inside the outer peripheral end 11 a of the platen glass 11. Thereby, the accumulation of foreign matter on the reference surface 21 in the vicinity of the support portion 22 is suppressed. The length between the outer peripheral end 22a of the support portion 22 and the outer peripheral end 11a of the platen glass 11 from the viewpoint of preventing the flat surface of the support portion 22 from being exposed even when there are variations in component dimensions and assembly. L2 is preferably in the range of 1 mm to 5 mm. Further, from the viewpoint of avoiding the application of a local force to the platen glass, the contact length L1 between the platen glass 11 and the support portion 22 is preferably in the range of 1 mm to 10 mm.

FIG. 5 is a perspective view showing another embodiment of the document reading apparatus according to the present invention. Document reader R ₂ shown in this figure, has a slit glass 32 to read the document conveyed by the automatic document feeder (not shown) (ADF), the opening 20 of the housing 2, the slit glass 32 And the platen glass 11.

  The slit glass 32 is attached by being fitted into the opening 30 of the guide member 31 attached to a part of the opening 20 of the housing 2. FIG. 6 shows a vertical cross-sectional view of both ends in the longitudinal direction of the slit glass 32, and FIG. 7 shows a vertical cross-sectional view of the central portion in the longitudinal direction of the slit glass 32. As shown in FIG. 6, the slit glass 32 is supported by receiving portions 31 a that are formed at both ends in the longitudinal direction of the guide member 31 and extend from the lower end of the side surface of the opening 30 to the inside of the opening. On the other hand, as shown in FIG. 7, no receiving portion is formed at the intermediate portion between the longitudinal ends of the guide member 31, and the side surface of the opening 30 of the guide member 31 and the side surface of the slit glass 32 contact each other. Since dust or dust may enter the inside of the housing 2 from the gap between the guide member 31 and the slit glass 32, the sheet extends over the guide member 31 and the slit glass 32 so as to close the contact surface. The member 34 is stuck. Of course, the receiving portion 31 a may be formed over the entire side surface of the opening 30 of the guide member 31 to support the slit glass 32.

  On the other hand, as shown in FIG. 5, the three sides of the platen glass 11 are supported by a support portion 22 formed in the housing 2, as in the above embodiment. The remaining one side of the platen glass 11 is supported by the guide member 31. Specifically, as shown in FIGS. 6 and 7, the one of the platen glasses 11 is formed in a rectangular cut 31 b formed on the side surface of the guide member 31 and having a height substantially equal to the thickness of the platen glass 11. The sides are fitted and the platen glass 11 is supported by the guide member 31. A document positioning member 33 that indicates a reference position when the document 10 is placed on the surface of the platen glass 11 is also fixedly supported on the platen glass 11 by the guide member 31.

  In order to attach the platen glass 11 to the housing 2 with high accuracy, a positioning portion may be provided in the housing 2. FIG. 8 is a partial perspective view showing an example of the positioning portion. An extended portion 221 that is wider than the others is provided in a part of the support portion 22 formed in the housing 2. Then, a square-shaped rising portion 23 is cut and raised from the end of the extended portion 221 on the opening side. The platen glass 11 is positioned with respect to the housing 2 by bringing the side surface of the platen glass 11 into contact with the rising portion 23. Note that the opening 24 formed after the rising portion 23 is cut and raised is filled with an elastic member 25 that is equal to or slightly thicker than the depth of the opening 24 from the inside of the housing 2. As a result, entry of foreign matter from the opening 24 into the housing 2 is prevented. The rising wall 23 may be provided for one side or two or more sides of the platen glass 11 and is preferably provided for at least two adjacent sides. One or more rising walls 23 may be provided for one side of the platen glass 11.

  In the document reading apparatus according to the present invention, the platen glass is supported by a support portion that is continuously formed around the periphery of the opening on the top surface of the housing and is one step higher than the other portions on the top surface of the housing. Since the platen glass and the support portion are in airtight contact with each other, the intrusion of foreign matter into the housing can be prevented without using a seal member or the like.

2 housings R ₁ and R ₂ original reading device 10 original 11 platen glass 11a outer peripheral edges 12a and 12b of platen glass traveling unit (optical component)
13 Image sensor (optical component)
DESCRIPTION OF SYMBOLS 20 Opening part 21 Reference surface 22 Support part 22a Outer peripheral edge of a support part 23 Standing part 24 Opening 25 Elastic member 31 Guide member 32 Slit glass

Claims (4)

A housing having an opening formed on the upper surface, an optical component attached in the housing, and a platen glass on which a document is placed, which is attached so as to seal at least a part of the opening of the housing. Have
The platen glass is supported by a support part that is continuously formed around the periphery of the opening and is one step higher than the other part of the upper surface of the housing, and the platen glass and the support part are in airtight contact with each other. Document reading device.   2. The document reading device according to claim 1, further comprising a slit glass for reading a document conveyed by the automatic document conveying device, wherein the opening of the housing is sealed by the platen glass and the slit glass.   The document reading apparatus according to claim 1, wherein an outer peripheral end of the support portion is located inside an outer peripheral end of the platen glass.   The rising portion for positioning the platen glass is cut and formed on the support portion, and the opening after the cut and raised is closed with an elastic member from the inside of the housing. Document reading device.