JP4516929B2 - Image reading device - Google Patents

Description

  The present invention relates to an improvement of an image reading apparatus such as a facsimile, a copier, a scanner, etc., and more particularly to an improvement for downsizing a casing.

  As an image reading apparatus that reads an image from a document placed on a contact glass, a mirror scan type and a modular scan type are generally known.

  As disclosed in, for example, Patent Document 1, a mirror scan type image reading apparatus includes a light source that irradiates a document placed on a contact glass, and a first light that reflects the light reflected from the document along the sub-scanning direction. A first carriage having a mirror, a second mirror that turns back the light reflected by the first mirror in a direction perpendicular to the surface of the contact glass, and the light reflected by the second mirror. A second carriage having a third mirror that is folded back along the sub-scanning direction in a direction opposite to the direction of reflection by the first mirror, and a housing for scaling the light reflected by the third mirror And a photoelectric conversion element such as a CCD provided at the end in the sub-scanning direction in the housing to form an image of the light transmitted from the lens, and moves along the sub-scanning direction. Same as the first carriage By moving the second carriage at half the moving speed direction, it is obtained so as to hold the optical path length extending from the first mirror to the lens and the photoelectric conversion element to a constant value.

  When such a structure is applied, a plurality of mirrors, lenses, and photoelectric conversion elements can be distributed and arranged in the first and second carriages and the casing, so that the first and second carriages can be reduced in size. In particular, since it is possible to reduce the size of the first carriage located directly below the contact lens, it is inconvenient when the first carriage is moved from one end to the other end in the sub-scanning direction of the contact lens. Thus, there is an advantage that the design for preventing mutual interference between the first carriage and the other members in the casing can be made relatively easily, and the casing can be downsized relatively easily.

  However, a plurality of mirrors, lenses, and photoelectric conversion elements are distributed in three locations of the first and second carriages and the casing, and the first and second carriages are independent of the casing. Between the first mirror attached to the first carriage and the second mirror attached to the second carriage, and the third mirror attached to the second carriage. There is an adverse effect that an error due to a positional deviation is likely to occur between the lens and the lens attached to the end in the sub-scanning direction in the housing, and as a result, an optical distortion is likely to occur in an image read by the photoelectric conversion element. .

  On the other hand, the modular scanning type image reading apparatus includes a light source that irradiates a document placed on a contact glass, a plurality of mirrors, lenses, and photoelectric conversion elements that fold light reflected from the document and guide it to the photoelectric conversion element. All of them are installed on the scanner module, and these components always move together. Therefore, there is a merit that the positional deviation between the components of the optical system does not occur and the image read by the photoelectric conversion element is hardly distorted. On the other hand, when comparing the size of the first carriage in the mirror scanning type image reading device and the size of the scanner module in the modular scanning type image reading device, the scanner module having all of the components of the optical system is integrated. The size will inevitably increase, and the scanner module will easily interfere with other members in the housing. There is also.

  In other words, in a general modular scan type image reading apparatus, normally, a cord, such as a wire or a timing belt, is fixed to each of both ends of the scanner module in the main scanning direction, and one end of the scanner module in the sub scanning direction. The scanner module is moved in the sub-scanning direction by winding the rigging at both ends of the scanner module with each of a pair of rigging take-up drums provided at both ends in the main scanning direction. In order to synchronize the rotation of the rigging take-up drum, the central axes of the rigging take-up drums at both ends must be integrally connected to the shaft and driven by a drive source such as a motor. However, as described above, since this shaft is positioned at the end of the casing so as to cross the main scanning direction, the scanner module is moved to the end of the casing along the sub-scanning direction. If it tries to do so, the scanner module and the shaft interfere with each other, and there is a problem that the scanner module cannot move to the end of the casing.

  As a result, the distance that the scanner module can actually move is shorter than the total length of the housing in the sub-scanning direction, and in order to read an image from a document of a target size, The overall length of the housing in the sub-scanning direction must be considerably longer than the maximum dimension, which makes it difficult to reduce the size of the housing.

Japanese Patent Laid-Open No. 2003-127774

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the disadvantages of the prior art and reduce the size of a modular scanning image reading apparatus.

The image reading apparatus of the present invention includes a light source that irradiates a document placed on a contact glass on an upper surface of a housing, a plurality of mirrors that fold light reflected from the document and guide it to a photoelectric conversion element, the mirror, A scanner module provided integrally with a lens provided between the photoelectric conversion element and a lens for scaling the light reflected by the mirror and forming an image on the photoelectric conversion element;
A pair of cords fastened to each of both ends of the scanner module in the main scanning direction and pulling the scanner module in the sub-scanning direction perpendicular to the main scanning direction;
A pair of rigging take-up drums provided at both ends in the main scanning direction at one end in the sub-scanning direction in the housing;
A modular scan type image reading apparatus including a shaft that is horizontally disposed in the casing along the main scanning direction and that is connected to a central axis of the rope winding drum to rotate synchronously. Especially because
At least one end in the sub-scanning direction of the scanner module is a notch that allows the scanner module to move to one end of the contact glass in the sub-scanning direction while avoiding interference between the shaft and the scanner module. A portion is formed.

As in the past, with the light source and the photoelectric conversion element activated, the shaft horizontally disposed along the main scanning direction at one end in the sub-scanning direction inside the housing is driven to rotate and provided at both ends in the main scanning direction. The pair of rigging take-up drums rotated synchronously to wind up the pair of rigging elements fixed to both ends of the scanner module in the main scanning direction, and in the sub-scanning direction perpendicular to the main scanning direction The image is read from the original placed on the contact glass on the upper surface of the housing while moving the.
At this time, the light from the light source reflected by the document is reflected by the plurality of mirrors, and further scaled by the lens and guided to the photoelectric conversion element.
Since a notch for avoiding interference with the shaft is formed at one end of the scanner module in the sub-scanning direction, the scanner module remains on the shaft even if the scanner module moves to one end of the contact glass in the sub-scanning direction. The image can be read over the entire surface of the contact glass on which the document is placed.
Accordingly, since the image can be read from a document of a desired size without greatly shifting the position of the shaft from one end of the contact glass in the sub-scanning direction to the outside, the housing in the sub-scanning direction A design with a reduced overall length can be easily realized.

  In addition, a drive source for driving the shaft is connected to one end of the shaft, and a pair of rigging holding drums that form a pair with the rigging take-up drum at the other end in the sub-scanning direction in the housing. It is desirable to apply a structure that is rotatably supported by support shafts that are independently provided at both ends in the scanning direction.

When such a configuration is applied, a pair of rigging holding drums that form a pair with the rigging take-up drum are pivotally supported independently at both ends in the main scanning direction at the other end in the sub-scanning direction. Therefore, there is no need to provide a member corresponding to the shaft between the rigging holding drums located at both ends in the main scanning direction. Therefore, the scanner module can reliably move to the other end of the contact glass in the sub-scanning direction without interfering with a member corresponding to the shaft.
In this way, since the image can be read from a document of a desired size without being offset from the other end portion of the contact glass in the sub-scanning direction and arranged with a rigging holding drum, the sub-scan is performed. A reduction in the overall length of the housing in the direction is realized.

  Further, the plurality of mirrors on the scanner module so that the optical path of the light reflected by the plurality of mirrors does not interfere with the shaft when the scanner module moves to one end of the contact glass in the sub-scanning direction. It is desirable that the attachment position and the attachment angle of the lens and the photoelectric conversion element are adjusted.

  A plurality of mirrors, lenses, and photoelectric conversion elements can be attached to various positions on the scanner module at various angles by selecting their optical characteristics. In other words, for the same purpose of reading a document, it is possible to arbitrarily design an optical path from a mirror that first receives reflected light from the document to a photoelectric conversion element on which light is imaged, so that interference with the shaft is avoided. By designing the optical path on the scanner module so as to avoid the notch for the purpose, it is possible to prevent optical interference between the optical path on the scanner module and the shaft that has entered the notch.

  According to the image reading apparatus of the present invention, the scanner module moves to one end of the contact glass in the sub-scanning direction by forming a notch for avoiding interference with the shaft at one end of the scanner module in the sub-scanning direction. However, since the scanner module is prevented from interfering with the shaft, an image can be obtained from a document of a desired size without greatly shifting the position of the shaft from one end of the contact glass in the sub-scanning direction to the outside. The total length of the housing in the sub-scanning direction can be easily shortened.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment in which the configuration of the image reading apparatus of the present invention is applied to a scanner.

  As shown in FIG. 1, the scanner 1 of the present embodiment generally includes a housing 2 that forms an exterior of the apparatus, a contact glass 3 fixed on the top surface of the housing 2, and the interior of the housing 2. The scanner module 4 for reading an image from a document placed on the contact glass 3, the annular wires 5, 5 functioning as a pair of cords pulling the scanner module 4, and the wires 5, 5 are wound A pair of pulleys 6 and 6 that function as a rigging take-up drum, a pair of pulleys 7 and 7 that function as a rigging holding drum that holds the wires 5 and 5 in cooperation with the pulleys 6 and 6, and a pulley A shaft 8 for connecting the central axes 6 and 6 to rotate synchronously and a gear motor 9 connected to one end of the shaft 8 and functioning as a drive source are provided.

  In addition to the wires 5 and 5, a timing belt can be used as the rigging device for pulling the scanner module 4. When the timing belt is used, a toothed pulley is used as a rigging take-up drum or a rigging holding drum. Is used.

  In the scanner 1 of this embodiment, the longitudinal direction of the housing 2, that is, the direction of the arrow Y shown in FIG. 1 corresponds to the sub-scanning direction of the scanner module 4, and the direction of the arrow X orthogonal to this is the main scanning of the scanner module 4. Corresponds to the direction.

  As shown in FIG. 1, the pair of pulleys 6 and 6 functioning as the rigging take-up drum are at one end in the sub-scanning direction within the housing 2, that is, at a position on the front side in the longitudinal direction of the housing 2 shown in FIG. The shafts 8 arranged at both ends in the main scanning direction for connecting and rotating the central axes of the pulleys 6 and 6 in synchronization with each other also follow the main scanning direction at a position on the front side in the longitudinal direction of the housing 2. It is laid along.

  On the other hand, the pair of pulleys 7, 7 functioning as a rigging drum is supported by a support shaft (not shown) provided independently at both ends in the main scanning direction at the position of the other end in the sub scanning direction in the housing 2. It is pivotally supported in an individually rotatable state.

  The wires 5 and 5 functioning as the rigging are individually fixed to both ends of the scanner module 4 in the main scanning direction, and the wires 5 and 5 are arranged on one side in the main scanning direction. , 7 and a set of pulleys 6, 7 arranged on the other side in the main scanning direction.

  Therefore, when the gear motor 9 is operated to rotate the shaft 8 and the pulleys 6 and 6 functioning as the rigging drum are rotated synchronously, both ends of the scanner module 4 in the main scanning direction are connected by the wires 5 and 5. It is possible to move the scanner module 4 in the opposite direction in the sub-scanning direction by pulling evenly.

As shown in FIG. 1, the pulleys 7 and 7 functioning as a rigging drum are rotatably held by independent spindles at positions on both sides in the main scanning direction at the other end in the sub scanning direction in the housing 2. Has been.
Since there is no member corresponding to the shaft 8 between the pulleys 7 and 7, the scanner module 4 reliably moves to the other end of the contact glass 3 in the sub-scanning direction without interfering with anything. can do.

A schematic configuration of the scanner module 4 of this embodiment is shown in a sectional view of FIG. As shown in FIG. 2, the scanner module 4 includes a light source 10 for irradiating a document placed on the contact glass 3, and five sheets of light reflected from the document and guided to a photoelectric conversion element 11 composed of a CCD or the like. Frame 12 includes mirrors 12a, 12b, 12c, 12d, and 12e, and a lens 13 that is provided between mirror 12e and photoelectric conversion element 11 and scales the light reflected by mirror 12e to form an image on photoelectric conversion element 11. 14 on one.
The light irradiated from the light source 10 and reflected by the original on the contact glass 3 is reflected back by the mirror 12a, mirror 12b, mirror 12c, mirror 12b, mirror 12d, and mirror 12e as shown in FIG. The image is formed on the photoelectric conversion element 11 through 13.

  A U-shaped notch 14a having a vertical width slightly exceeding the diameter of the shaft 8 is formed at one end of the frame 14 in the sub-scanning direction, that is, the right end of the frame 14 shown in FIG. Even when the module 4 moves to one end portion of the contact glass 3 in the sub-scanning direction, that is, the end portion on the front side in the longitudinal direction of the housing 2 in FIG. 1, the scanner module 4 and the shaft 8 do not interfere with each other. As described above, the entire surface of the document placed on the contact glass 3 is coupled with the fact that the scanner module 4 can move to the other end of the contact glass 3 in the sub-scanning direction without interfering with other members. In particular, an image can be reliably read from one end to the other end in the sub-scanning direction.

2, the scanner module 4 has one end portion of the contact glass 3 in the sub-scanning direction, that is, the longitudinal direction of the housing 2 in FIG. 1. When the movement limit of the front end is reached, a part of the optical path of the reflected light from the mirror 12d to the mirror 12e is blocked by the shaft 8 as shown in FIG. 3, for example. Since the reading range, that is, the area where the document can be placed is restricted by the frame portions 2a formed at the four corners of the upper surface of the housing 2, the movement limit of one end portion of the contact glass 3 in the sub-scanning direction of the contact glass 3 The interference between the optical path between the mirrors 12d and 12e and the shaft 8 that occurs at the time of reaching the position does not become a substantial obstacle to reading the document.
The movement position of the scanner module 4 when reading the light reflected from the document at the end position on the near side in the longitudinal direction of the contact glass 3 regulated by the frame portion 2a is represented by the position of the notch portion 14a in the frame 14. 3 is indicated by an imaginary line 14a ′. That is, in a state where the scanner module 4 is at a position represented by reference numeral 14a ′ in FIG. 3, the light path reflected by the original and directed to the first mirror 12a is the optical path L1 in FIG. The optical path of the reflected light that is folded back by the mirror 12d and reaches the mirror 12e is the optical path L2 in FIG. 3, and this optical path L2 does not interfere with the shaft 8.

  Further, if the optical system is changed by adjusting the mounting position and mounting angle of the mirror, the lens and the photoelectric conversion element provided in the scanner module 4, it will occur when the scanner module 4 reaches the movement limit at one end in the sub-scanning direction. It is also possible to prevent interference between the optical path between the mirrors 12d and 12e and the shaft 8.

  By changing the mounting angle of the mirrors 12d and 12e with respect to the frame 14 and installing another mirror 12f, an optical path is formed around the notch 14a in the frame 14 to prevent interference between the shaft 8 and the optical path. In the example shown in FIG. 4, and by changing the mounting position of the mirrors 12d and 12e with respect to the frame 14, the optical path is formed by bypassing the notch portion 14a in the frame 14, thereby preventing interference between the shaft 8 and the optical path. An example of this is shown in FIG.

  In any case, the optical path length from the mirror 12c that first receives the reflected light from the document to the photoelectric conversion element 11 changes as compared with the configuration example of FIG. 3, but by appropriately selecting the magnification of the lens 13 An optical system substantially equivalent to the configuration example of FIG. 3 can be configured.

In this way, if the notch 14a is formed deeper while preventing the optical path between the mirrors 12d and 12e and the shaft 8 from being interfered, the scanner module 4 is further overlapped with the shaft 8. It can be moved toward one end in the sub-scanning direction.
Therefore, in comparison with FIG. 3, even if the contact glass 3 on the housing 4 is formed larger in the sub-scanning direction as shown in FIGS. 4 and 5, for example, it is placed on the contact glass 3. The original image can be read reliably.
If the size of the contact glass 3, that is, the size of the document to be read is the same, the width of the frame 2a in the housing 2 shown in FIGS. 4 and 5 is set to the frame shown in FIG. Since it can be formed narrower than the portion 2a, the outer shape of the housing 2, that is, the scanner 1, can be further reduced.

1 is a perspective view showing an embodiment in which the configuration of an image reading apparatus of the present invention is applied to a scanner. It is sectional drawing which showed the outline of the structure of the scanner module in the embodiment. It is the conceptual diagram which simplified and showed the attachment position and attachment angle of the mirror in the scanner module. It is the conceptual diagram simplified and shown about another example of the attachment position and attachment angle of a mirror. It is the conceptual diagram simplified and shown about another example of the attachment position and attachment angle of a mirror.

Explanation of symbols

1 Scanner (image reading device)
2 Housing 2a Frame 3 Contact glass 4 Scanner module 5 Wire (rigging)
6 Pulley (rigging drum)
7 Pulley (rigging drum)
8 Shaft 9 Geared motor (drive source)
DESCRIPTION OF SYMBOLS 10 Light source 11 Photoelectric conversion element 12a, 12b, 12c, 12d, 12e Mirror 13 Lens 14 Frame 14a Notch

Claims (3)

Provided between the mirror and the photoelectric conversion element, a light source for irradiating the original placed on the contact glass on the upper surface of the housing, a plurality of mirrors for reflecting light reflected from the original and guiding it to the photoelectric conversion element A scanner module integrally provided with a lens for scaling the light reflected by the mirror and forming an image on the photoelectric conversion element;
A pair of cords fastened to each of both ends of the scanner module in the main scanning direction and pulling the scanner module in a sub-scanning direction perpendicular to the main scanning direction;
A pair of rigging take-up drums provided at both ends in the main scanning direction at one end in the sub-scanning direction in the housing;
In an image reading apparatus comprising: a shaft that is horizontally installed in the casing along the main scanning direction and that is connected to a central axis of the rigging take-up drum for synchronous rotation.
At least one end in the sub-scanning direction of the scanner module is a notch that allows the scanner module to move to one end of the contact glass in the sub-scanning direction while avoiding interference between the shaft and the scanner module. An image reading apparatus characterized in that a part is formed.   One end of the shaft is connected to a drive source that drives the shaft, and a pair of rigging holding drums that form a pair with the rigging take-up drum at the other end in the sub-scanning direction in the housing, 2. The image reading apparatus according to claim 1, wherein the image reading apparatus is rotatably supported by support shafts provided independently at both ends in the main scanning direction.   The plurality of mirrors and lenses on the scanner module so that the optical path of the light reflected by the plurality of mirrors does not interfere with the shaft when the scanner module moves to one end of the contact glass in the sub-scanning direction; The image reading apparatus according to claim 1, wherein an attachment position and an attachment angle of the photoelectric conversion element are adjusted.

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