JP2012244486A - Image reading apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading apparatus that can reduce manufacturing costs.SOLUTION: A spacer part 43 and a guided part 44 are integrally formed with the same material in a mounting member 40. During a first reading process, the spacer part 43 is contacted with a rear surface of a first transparent plate, thereby keeping a certain distance between the first transparent plate and an image reading part 3. During a second reading process, the spacer 43 is contacted with a rear surface of a second transparent plate, thereby keeping a certain distance between the second transparent plate and the image reading part 3. When the image reading part 3 slides between the first transparent plate side and the second transparent plate side, the guided part 44 is guided along a guide part formed on a rear surface of a cover member configured to attach the first transparent plate and the second transparent plate thereto, and space is formed between the spacer part 43 and the rear surface of the cover member. By integrally forming the spacer part 43 and the guided part 44 with the same material in the mounting member 40, the number of parts can be reduced, thus reducing manufacturing costs.

Description

  The present invention relates to an image reading apparatus for reading an image of a document by irradiating light from a light emitting unit toward the document and receiving light reflected from the document by a light receiving unit.

  For example, an image reading apparatus including a contact image sensor called a CIS (Contact Image Sensor) as an image reading unit is known (see, for example, Patent Document 1). The CIS includes a light emitting unit and a light receiving unit, and scanning is performed by a holding member that holds the CIS being slid parallel to the document.

  In this type of image reading apparatus, a first glass plate and a second glass plate are provided, and a first reading process for reading a document on the surface of the first glass plate and a document on the surface of the second glass plate. Some of them can execute the second reading process. More specifically, in the first reading process, with the document placed on the surface of the first glass plate, the CIS is slid to read the image of the document. On the other hand, in the second reading process, the document is transported on the surface of the second glass plate by transporting the document on the surface of the second glass plate using the document transport device (ADF) while the CIS is stationary. Read the image of the original to be printed.

  Since CIS has a shallow depth of focus, it has a characteristic that a focus shift is likely to occur unless the accuracy of the distance to the document is high. Therefore, the CIS is usually provided with a spacer that contacts the back surface of the first glass plate during the first reading process and that contacts the back surface of the second glass plate during the second reading process (for example, Patent Document 2 and 3). With this spacer, the distance between the first glass plate and the CIS can be kept constant during the first reading process, and the distance between the second glass plate and the CIS can be kept constant during the second reading process. Can be suppressed.

  However, when the spacer as described above is provided, a cover member that holds the first glass plate and the second glass plate when the CIS slides between the first glass plate side and the second glass plate side. It is necessary to prevent the spacer from rubbing on the back surface of the substrate. Therefore, in the configurations disclosed in Patent Documents 2 and 3, a guided member (such as a shaft member or a roller) attached to the CIS is guided along a guide portion formed on the back surface of the cover member. A space is formed between the spacer and the back surface of the cover member.

JP 2006-213353 A JP 2002-218176 A JP 2005-184720 A

  In the configurations disclosed in Patent Documents 2 and 3, since the spacer and the guided member are attached to the CIS as separate members, there is a problem that the manufacturing cost increases due to an increase in the number of parts.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image reading apparatus capable of reducing the manufacturing cost.

  An image reading apparatus according to the present invention includes an image reading unit having a light emitting unit and a light receiving unit. With the document placed on the surface of the first transparent plate, the image reading unit is slid to display an image of the document. An image reading apparatus capable of executing a first reading process for reading and a second reading process for reading an image of a document conveyed on the surface of the second transparent plate with the image reading unit stationary. A holding member that holds the image reading unit, a housing that houses the holding member in a slidable state, the first transparent plate and the second transparent plate are mounted side by side in the sliding direction of the holding member, A cover member for covering the housing; and an attachment member attached to the image reading unit. The attachment member contacts the back surface of the first transparent plate during the first reading process. 1 with a transparent plate The distance between the image reading unit and the image reading unit is kept constant by contacting the back surface of the second transparent plate during the second reading process. When the image reading unit slides between the spacer unit, the first transparent plate side, and the second transparent plate side, the guide unit is guided along a guide unit formed on the back surface of the cover member. The guided portion for forming a space between the spacer portion and the back surface of the cover member is integrally formed of the same material.

  According to such a structure, the spacer part which contacts the back surface of a 1st transparent plate and a 2nd transparent plate, and the to-be-guided part guided along the guide part formed in the back surface of a cover member are attachment members. Therefore, the manufacturing cost can be reduced by reducing the number of parts. Since both the spacer part and the guided part are preferably formed of a material having a relatively small coefficient of dynamic friction from the viewpoint of improving slippage, the spacer part and the guided part are efficiently formed by integrally forming the spacer part and the guided part. The manufacturing cost can be reduced well.

  The attachment member may be detachable from the image reading unit.

  According to such a configuration, the attachment member can be detached from the image reading unit as necessary. For example, when the mounting member is worn, it is possible to remove the mounting member from the image reading unit and replace it with a new mounting member. In addition, when replacing the image reading unit, the attachment member can be detached from the image reading unit and attached to a new image reading unit.

  The image reading unit may have a long shape extending in a direction orthogonal to the sliding direction of the holding member, and the attachment members may be attached to both ends in the longitudinal direction of the image reading unit. .

  According to such a configuration, the distance between the first transparent plate and the image reading unit and the second transparent plate and the image reading by the spacer portions of the attachment members attached to both ends in the longitudinal direction of the image reading unit. The distance to the part can be kept stable and constant. In addition, the image reading unit can be stably guided along the guide unit by the guided portions of the attachment members attached to both ends in the longitudinal direction of the image reading unit.

  The guided portion is formed at a central portion of the mounting member in the sliding direction, and the same mounting member is attached to both ends of the image reading portion in the longitudinal direction. The guide part may be located on the same axis along the orthogonal direction.

  According to such a configuration, the same mounting member is attached to both ends in the longitudinal direction of the image reading unit, so that the guided portion of each mounting member is coaxially positioned along the direction orthogonal to the sliding direction. Therefore, the image reading unit can be stably guided along the guide unit. Further, by using the same mounting member, the number of parts can be reduced and the manufacturing cost can be reduced.

1 is a schematic cross-sectional view illustrating an internal configuration of an image forming apparatus including an image reading apparatus according to an embodiment of the present invention. It is the perspective view which showed an example of the internal structure of an upper housing, and has shown the state which removed the upper surface board. It is a perspective view which shows the structure of the edge part of an image reading part. It is the perspective view which looked at the upper surface board from the back surface side. It is the perspective view which expanded the principal part of FIG. It is the fragmentary sectional view which showed an example of the internal structure of an upper housing.

  FIG. 1 is a schematic cross-sectional view showing an internal configuration of an image forming apparatus 1 including an image reading apparatus according to an embodiment of the present invention. In this embodiment, a configuration in which the image reading apparatus is provided in the image forming apparatus 1 will be described as an example of the image reading apparatus. However, the image reading apparatus is configured by another apparatus such as a scanner apparatus or a facsimile apparatus. May be. Further, the specific configuration of the image forming apparatus 1 described below is not limited to that configuration.

  The image forming apparatus 1 according to the present embodiment reads, for example, an image of a document automatically supplied by a document transport device (ADF) 2 one by one by an image reading unit 3 and records paper based on the image data of the document. A copier that forms an image on P. The image forming apparatus 1 is provided with an image forming unit 4 and a paper feeding unit 5 in addition to the image reading unit 3 in the housing 1a, and a document conveying device 2 is provided on the upper surface of the housing 1a. ing.

  The document transport device 2 includes a document tray 2a, and a document can be set on the document tray 2a. The document conveying device 2 feeds the documents set on the document tray 2a one by one by the pickup roller 2b and the sheet separating device 2c. The sheet separating device 2c includes, for example, a separation roller 20 and a separation pad 21. The sent document is transported on the document transport path 2g by a plurality of document transport rollers 2d, 2e, and 2f, and passes through the second glass plate 3c in the middle of the document transport path 2g by the image reading unit 3. The image is read. The document after the image is read is sequentially discharged onto the document discharge tray 2i by the discharge roller 2h.

  The image reading unit 3 is accommodated in an upper casing 31 that constitutes a part of the casing 1a. The image reading unit 3 is configured by, for example, a CIS (contact image sensor), and is provided with a light emitting unit 33 and a light receiving unit 34 such as a CMOS (Complementary Metal Oxide Semiconductor) sensor.

  The image reading unit 3 irradiates the document placed on the first glass plate 3d while moving the light emitting unit 33 in the horizontal direction (sub-scanning direction) orthogonal to the main scanning direction, and reflects the reflected light from the document. By receiving light at the light receiving unit 34, an image of the document can be read. Further, the image reading unit 3 irradiates light from the light emitting unit 33 toward the second glass plate 3c in a stationary state, and reflects reflected light from a document conveyed on the second glass plate 3c by the document conveying device 2. By receiving the light at the light receiving unit 34, it is possible to read the image of the document.

  When reading a document placed on the first glass plate 3d, main scanning is performed by receiving reflected light from the document by the light receiving unit 34, and the light emitting unit 33 moves in the sub scanning direction to perform sub scanning. A scan is performed. On the other hand, when reading originals conveyed on the second glass plate 3c one by one by the original conveying apparatus 2, main scanning is performed by receiving reflected light from the original by the light receiving unit 34, and the second scanning is performed. Sub-scanning is performed by conveying the document on the glass plate 3c.

  The first glass plate 3d and the second glass plate 3c are formed on the upper surface plate 32 constituting the upper surface of the upper casing 31, and the document conveying device 2 is attached to the upper surface plate 32 so as to be opened and closed vertically. Yes. Therefore, when the original placed on the first glass plate 3d is read by the image reading unit 3, the original is placed between the original conveying device 2 and the first glass plate 3d by closing the original conveying device 2. It can be pinched. That is, the document feeder 2 constitutes an open / close cover 10 that is opened and closed to hold the document placed at the set position on the first glass plate 3d. However, the opening / closing cover 10 is not limited to the one constituted by the document conveying device 2, and any other cover that can be opened and closed can be adopted.

  The image forming unit 4 includes a photosensitive drum 4a, a charger 4b, an optical writing unit 4c, a developing unit 4d, a transfer unit 4e, and a fixing unit 4f, and forms an image on the recording paper P by an electrophotographic method. A photoconductor is formed on the surface of the photoconductor drum 4a. During image formation, the surface of the photoconductor drum 4a that is rotationally driven is uniformly charged by the charger 4b. The optical writing unit 4 c outputs light from an LED (Light-Emitting Diode) or a laser light source based on the image data of the original read by the image reading unit 3. An electrostatic latent image is formed on the surface of the photosensitive drum 4a uniformly charged by the charger 4b by exposure with light output from the optical writing unit 4c.

  A toner image is formed on the surface of the photosensitive drum 4a on which the electrostatic latent image has been formed by adhering the toner supplied from the developing device 4d, and this toner image is formed on the recording paper P using the transfer device 4e. Transcribed. The recording paper P to which the toner image has been transferred is subjected to a heat treatment and a pressure treatment by the fixing device 4f, and is then discharged from the discharge roller 4g onto the discharge tray 4h.

  The paper supply unit 5 includes a paper supply cassette 6 for storing the recording paper P, and stores the recording paper P in a stacked state on a support plate 9 provided in the paper supply cassette 6. Can be done. The support plate 9 is rotatable about the axis 9a at the first end, and the second end opposite to the first end is biased upward by the compression spring 9b. The uppermost recording paper P is pressed against the paper feed roller 7. For example, a separation pad (not shown) is disposed at a position facing the paper feed roller 7, and the recording paper P delivered from the paper feed cassette 6 when the paper feed roller 7 is rotationally driven is One sheet is sent to the recording paper conveyance path 12 by the action of the separation pad.

  The recording paper transport path 12 is provided with one or a plurality of recording paper transport rollers 13. The recording paper P delivered one by one from the paper feed cassette 6 is transported through the recording paper transporting path 12 by the recording paper transporting roller 13 and sent to the image forming unit 4. Then, the recording paper P is temporarily stopped by the registration roller 14 immediately before the photosensitive drum 4a, and is sent out in accordance with the transfer timing of the toner image formed on the photosensitive drum 4a.

  FIG. 2 is a perspective view showing an example of the internal configuration of the upper casing 31, and shows a state in which the top plate 32 is removed. The image reading unit 3 accommodated in the upper casing 31 is held by a holding member 35. A support rail 311 for supporting the holding member 35 upward in a slidable state is formed integrally with the bottom surface of the upper casing 31. However, the support rail 311 is not limited to the configuration formed integrally with the bottom surface of the upper casing 31.

  The support rail 311 extends in a straight line, for example, along the sub-scanning direction D2 orthogonal to the main scanning direction D1 of the image reading unit 3. Since the holding member 35 is supported on the support rail 311, the holding member 35 can slide along the sub-scanning direction D <b> 2. A drive belt 36 that is driven to slide the holding member 35 is provided in the upper housing 31.

  The holding member 35 has a long shape extending in a direction orthogonal to the slide direction (main scanning direction D1). The holding member 35 is supported at the center in the longitudinal direction by the support rail 311, and one end in the longitudinal direction is guided along the slide direction (sub-scanning direction D <b> 2). The central portion is a concept that includes not only the center of the holding member 35 in the longitudinal direction but also a range deviated from the center to some extent.

  In this example, the rear end 351 of the holding member 35 is guided in surface contact with a guide surface 312 formed on the bottom surface of the upper housing 31. Therefore, the image reading unit 3 is configured such that the center of gravity thereof is positioned on the end 351 side of the support rail 311, so that the end 351 is always in contact with the guide surface 312. However, the present invention is not limited to the above configuration, and various other configurations such as a configuration in which the front end portion 352 of the holding member 35 is guided can be employed.

  In the present embodiment, it is possible to execute a first reading process for reading an image of a document by sliding the image reading unit 3 and a second reading process for reading an image of a document while the image reading unit 3 is stationary. In the first reading process, with the document placed on the surface of the first transparent plate (first glass plate 3d), the image reading unit 3 is slid to read the image of the document. On the other hand, in the second reading process, the image of the document conveyed on the surface of the second transparent plate (second glass plate 3c) is read while the image reading unit 3 is stationary.

  The first glass plate 3d and the second glass plate 3c are attached side by side in the sliding direction (sub-scanning direction D2) of the holding member 35 with respect to the upper surface plate 32 constituting the cover member for covering the upper casing 31. . However, the first transparent plate and the second transparent plate can be made of a material other than the glass plate.

  FIG. 3 is a perspective view illustrating a configuration of an end portion of the image reading unit 3. The image reading unit 3 has a long shape extending in a direction orthogonal to the sliding direction of the holding member 35 (main scanning direction D1), and an attachment member 40 can be attached to and detached from the end of the image reading unit 3. Is attached. In this example, the attachment members 40 are attached to both ends in the longitudinal direction of the image reading unit 3. However, since each attachment member 40 has the same configuration and attachment manner, the attachment member 40 has one end of the image reading unit 3. Only the configuration will be described.

  The attachment member 40 includes a first plate portion 41 that faces the end surface of the image reading unit 3 and a second plate portion 42 that protrudes in the same direction from both ends of the first plate portion 41 in the vertical direction. By being formed, it is configured in a U shape. A fixing portion (not shown) made of, for example, a convex portion or a concave portion is formed on the surface of the mounting member 40 facing the image reading portion 3 of the second plate portion 42, and the fixing portion is formed on the image reading portion 3. The attachment member 40 is attached to the image reading unit 3 by fitting with the corresponding concave or convex portion formed.

  The second plate portion 42 on the upper side of the attachment member 40 faces the back surfaces (lower surfaces) of the glass plates 3c and 3d during the first reading process and the second reading process. The upper surface of the second plate portion 42 is set at a position higher than, for example, the upper surface of the image reading unit 3. With such a configuration, the spacer portion 43 that contacts the glass plates 3 c and 3 d is formed on the upper surface of the upper second plate portion 42 of the attachment member 40.

  During the first reading process, the distance between the first glass plate 3d and the image reading unit 3 is kept constant by the spacer 43 coming into contact with the back surface of the first glass plate 3d. On the other hand, in the second reading process, the distance between the second glass plate 3c and the image reading unit 3 is kept constant by the spacer 43 coming into contact with the back surface of the second glass plate 3c. The CIS that constitutes the image reading unit 3 has a characteristic that the focal depth is shallow unless the depth of focus is shallow and the distance from the document is high. By keeping the distance between 3d and the image reading unit 3 constant, it is possible to suppress a shift in focus.

  The first plate portion 41 of the attachment member 40 is formed with a guided portion 44 that protrudes in a direction opposite to the direction in which the second plate portion 42 protrudes. The guided portion 44 has, for example, a cylindrical shaft shape. However, the guided portion 44 is not limited to a cylindrical shape, and can be formed in various other shapes.

  FIG. 4 is a perspective view of the top plate 32 as viewed from the back side. FIG. 5 is an enlarged perspective view of a main part of FIG. FIG. 6 is a partial cross-sectional view showing an example of the internal configuration of the upper casing 31. As shown in FIGS. 4 to 6, a guide portion 321 that can contact the guided portion 44 of the mounting member 40 is formed on the back surface (lower surface) of the upper surface plate 32.

  The guide part 321 is comprised by the rib formed so that it might protrude from the back surface of the upper surface board 32 between the 1st glass plate 3d and the 2nd glass plate 3c, for example. As shown in FIG. 4, it is preferable that the guide part 321 is formed in the vicinity of both end parts in the main scanning direction D1 of the first glass plate 3d and the second glass plate 3c. Further, as shown in FIG. 5, the guide portion 321 is formed with a tapered surface 322 that gradually decreases in height toward the first glass plate 3d side and the second glass plate 3c side. Is preferred.

  As shown in FIG. 6, when the image reading unit 3 slides between the first glass plate 3 d side and the second glass plate 3 c side, the attachment members 40 attached to both end portions of the image reading unit 3. The guided portion 44 contacts the guide portion 321 of the upper surface plate 32. The lowermost surface 323 of the guide part 321 is set at a position lower than the position of the upper part of the guided part 44, and the upper part of the guided part 44 is pushed down by the lowermost surface 323 via the tapered surface 322 of the guide part 321. It is supposed to be.

  The image reading unit 3 is held by the holding member 35 via a compression spring 354 that is an example of a pressing member. Accordingly, the image reading unit 3 is pressed toward the first glass plate 3d during the first reading process, and is pressed toward the second glass plate 3c during the second reading process. When the image reading unit 3 slides between the first glass plate 3 d side and the second glass plate 3 c side, the upper portion of the guided portion 44 is against the pressing force of the compression spring 354. It is pushed down by the lowermost surface 323. However, the pressing member is not limited to the compression spring 354, and other various members such as rubber can be employed.

  As shown in FIG. 6, when the image reading unit 3 slides between the first glass plate 3 d side and the second glass plate 3 c side, along the guide unit 321 formed on the back surface of the top plate 32. By guiding the guided portion 44, a space 60 is formed between the spacer portion 43 and the back surface of the upper surface plate 32. On the side surface of the holding member 35, a notch 355 is formed below the guided portion 44 in order to prevent the guided portion 44 guided along the guide portion 321 from contacting the side surface.

  In this embodiment, the spacer part 43 which contacts the back surface of the 1st glass plate 3d and the 2nd glass plate 3c, and the to-be-guided part 44 guided along the guide part 321 formed in the back surface of the upper surface board 32 are included. The mounting member 40 is integrally formed of the same material. Therefore, the number of parts can be reduced and the manufacturing cost can be reduced.

  Both the spacer portion 43 and the guided portion 44 are preferably formed of a material having a relatively small dynamic friction coefficient from the viewpoint of improving slippage. The dynamic friction coefficients of the spacer portion 43 and the guided portion 44 are preferably 0.15 or less, and more preferably 0.1 or less. For example, the entire attachment member 40 may be formed of a resin such as PA (polyamide), PET (polyethylene terephthalate), or POM (polyacetal). Thus, the manufacturing cost can be efficiently reduced by integrally forming the spacer portion 43 and the guided portion 44, which are preferably made of a material having a relatively small dynamic friction coefficient.

  In the present embodiment, since the attachment member 40 is detachable from the image reading unit 3, the attachment member 40 can be detached from the image reading unit 3 as necessary. For example, when the attachment member 40 is worn, the attachment member 40 can be removed from the image reading unit 3 and replaced with a new attachment member 40. Further, when replacing the image reading unit 3, the attachment member 40 can be detached from the image reading unit 3 and attached to a new image reading unit 3.

  Furthermore, since the attachment members 40 are attached to both ends in the longitudinal direction of the image reading unit 3, the distance between the first glass plate 3d and the image reading unit 3 is determined by the spacers 43 of the attachment members 40, and The distance between the second glass plate 3c and the image reading unit 3 can be kept stable and constant. Further, the image reading unit 3 can be stably guided along the guide unit 321 by the guided portions 44 of the attachment members 40 attached to both ends in the longitudinal direction of the image reading unit 3.

  In the present embodiment, as shown in FIGS. 3 and 6, the guided portion 44 is formed at the center of the mounting member 40 in the sliding direction (sub-scanning direction D2). Therefore, by attaching the same mounting member 40 to both ends in the longitudinal direction of the image reading unit 3, the guided portion 44 of each mounting member 40 is along a direction orthogonal to the slide direction (main scanning direction D1). Located on the same axis. As a result, the image reading unit 3 can be stably guided along the guide unit 321, and by using the same mounting member 40, the number of parts can be reduced and the manufacturing cost can be reduced.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 1a Housing 2 Document conveying apparatus 3 Image reading part 3d 1st glass plate (1st transparent plate)
3c Second glass plate (second transparent plate)
31 Upper housing 32 Upper surface plate 33 Light emitting portion 34 Light receiving portion 35 Holding member 40 Mounting member 43 Spacer portion 44 Guided portion 321 Guide portion

Claims (4)

A first reading process that includes an image reading unit having a light emitting unit and a light receiving unit, and reads the image of the document by sliding the image reading unit in a state where the document is placed on the surface of the first transparent plate; An image reading apparatus capable of executing a second reading process for reading an image of a document conveyed on the surface of the second transparent plate with the image reading unit stationary.
A holding member for holding the image reading unit;
A housing that houses the holding member in a slidable state;
The first transparent plate and the second transparent plate are mounted side by side in the sliding direction of the holding member, and a cover member for covering the housing;
An attachment member attached to the image reading unit,
In the mounting member,
During the first reading process, the distance between the first transparent plate and the image reading unit is kept constant by contacting the back surface of the first transparent plate, and during the second reading process, the second transparent plate A spacer portion for maintaining a constant distance between the second transparent plate and the image reading portion by contacting the back surface;
When the image reading unit slides between the first transparent plate side and the second transparent plate side, the spacer unit is guided along a guide unit formed on the back surface of the cover member. And an underside of the cover member, a guided portion for forming a space is integrally formed of the same material.   The image reading apparatus according to claim 1, wherein the attachment member is detachable from the image reading unit. The image reading unit has a long shape extending in a direction orthogonal to the sliding direction of the holding member,
The image reading apparatus according to claim 1, wherein the attachment member is attached to both ends in the longitudinal direction of the image reading unit. The guided portion is formed in a central portion of the mounting member in the sliding direction;
The same mounting member is attached to both end portions in the longitudinal direction of the image reading unit, so that the guided portions of the mounting members are coaxially positioned along the orthogonal direction. The image reading apparatus according to claim 3.

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