JP2013131974A - Image reading device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading device, equipped with a line sensor, which enables a positional adjustment of the CCD line sensor even after factory shipment.SOLUTION: The image reading device, equipped with a line sensor which receives light reflected from an original document and converts it to an electric signal, comprises a piezo-electric element 31 which moves a line sensor 26d2 along a plane perpendicular to an optical axis of the reflected light.

Description

  The present invention relates to an image reading apparatus and an image forming apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine, a facsimile machine, or a multifunction machine having a plurality of these functions has an image reading device for reading an image of a document. Such an image reading apparatus includes a light source that emits irradiation light having a linear irradiation pattern on a document, and a CCD line sensor that receives reflected light from the document and converts it into an electrical signal.

JP 2000-115491 A

  In general, the CCD line sensor is mounted on a substrate, and the substrate is fixed to the inside of the housing of the image reading device by being attached to the frame of the image reading device. The arrangement position of the CCD line sensor affects the reading accuracy of the image, and is accurately adjusted using a dedicated jig at the time of assembly in the factory.

However, even if alignment is performed accurately at the time of shipment from the factory, distortion may occur due to thermal deformation or the like depending on the use environment of the image reading apparatus, and the position of the CCD line sensor may be shifted. Further, the position of the CCD line sensor may be displaced due to stress or the like when closing a screw for fixing the CCD line sensor during assembly at the factory. For this reason, it may be difficult to maximize the image reading accuracy.
For example, since the shape of the CCD line sensor and the shape of the irradiation pattern of the reflected light are in line with each other, when the CCD line sensor is displaced so as to rotate around the optical axis of the reflected light, the CCD line sensor In some cases, the end of the slab may deviate significantly from the irradiation pattern of the reflected light. Actually, since the reflected light is scattered, the shape of the reflected light irradiation pattern becomes a blurred line. Even if the CCD line sensor deviates from the reflected light irradiation pattern when there is no scattered light. It is possible to read an image. However, since the range of the reflected light irradiation pattern when it is assumed that there is no scattered light is a region with a large amount of light, a part of the CCD line sensor is based on the reflected light irradiation pattern when it is assumed that there is no scattered light. By deviating greatly, the received light intensity of the part decreases, and the image reading accuracy decreases.

  When the position of the CCD line sensor is shifted in this way, to restore high reading accuracy, it is necessary to return the image reading apparatus to the factory once and readjust the position of the CCD line sensor with a dedicated jig. is there.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to make it possible to adjust the position of a CCD line sensor even after factory shipment in an image reading apparatus including a line sensor.

  The present invention adopts the following configuration as means for solving the above-described problems.

  According to a first aspect of the present invention, there is provided an image reading apparatus including a line sensor that receives reflected light from a document and converts the light into an electric signal, and the line sensor is disposed along a plane orthogonal to the optical axis of the reflected light. A configuration in which a moving piezoelectric element is provided is adopted.

  According to a second invention, in the first invention, as the piezoelectric element, a first piezoelectric element that is arranged apart from the longitudinal direction of the line sensor and moves the line sensor in a direction orthogonal to the longitudinal direction. And the structure provided with a 2nd piezoelectric element is employ | adopted.

  According to a third invention, in the first or second invention, a configuration is adopted in which a third piezoelectric element that moves the line sensor in the longitudinal direction is provided as the piezoelectric element.

  According to a fourth invention, in any one of the first to third inventions, a configuration is provided in which a substrate on which the line sensor is mounted is provided, and the piezoelectric element is in contact with the substrate.

  According to a fifth invention, in any one of the first to fourth inventions, a housing that houses the line sensor, a temperature sensor that detects a temperature inside or outside the housing, and a detection result of the temperature sensor And a control means for controlling the piezoelectric element based on the above.

  A sixth invention is an image forming apparatus, and employs a configuration including the image reading apparatus according to any one of the first to fifth inventions.

According to the present invention, the piezoelectric element for moving the line sensor is provided. For this reason, it becomes possible to adjust the position of a line sensor with a piezoelectric element.
In such a piezoelectric element, the amount of displacement (amount of change) varies depending on the value of the applied voltage. Therefore, even after factory shipment, the displacement amount of the piezoelectric element, that is, the position of the line sensor can be easily adjusted.
Therefore, even when the position of the line sensor is shifted due to thermal deformation or the like, the line sensor can always be moved to a region with a large amount of light, and high reading accuracy can always be maintained.

1 is a longitudinal sectional view schematically showing a schematic configuration of an image reading apparatus according to a first embodiment of the present invention. It is an enlarged view of the imaging unit in FIG. It is the front view which looked at the image pick-up unit of Drawing 2 from the back side of a CCD substrate. 3 is a flowchart for explaining a method of adjusting the position of the CCD line sensor in the image reading apparatus according to the first embodiment of the present invention. It is a longitudinal cross-sectional view which shows typically schematic structure of the image reading apparatus in 2nd Embodiment of this invention. It is a schematic block diagram of the image forming apparatus in 3rd Embodiment of this invention.

  Hereinafter, an embodiment of an image reading apparatus according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

(First embodiment)
FIG. 1 is a longitudinal sectional view schematically showing a schematic configuration of an image reading apparatus 1 of the present embodiment.
The image reading apparatus 1 according to the present embodiment is disposed on an upper part of an image forming apparatus such as a copying machine, a facsimile machine, or a multifunction machine having a plurality of these functions, and reads an image formed on a document.

  As shown in FIG. 1, the image reading apparatus 1 includes a main body 2, a displacement mechanism 3, a platen cover 4, and a control device 5 (control means).

The main body 2 includes a platen glass 21 that forms the upper surface of the main body 2, a housing 22 that supports the platen glass 21, and an optical device 23 that is disposed inside the housing 22 and below the platen glass 21. I have.
The main body 2 is provided with an operation panel for receiving instructions from the user as required. However, when it is assumed that the image reading apparatus 1 is connected to other devices (such as a main body of an image forming apparatus or a personal computer) provided with an operation panel, the operation panel of the main body 2 may be omitted. .

  The platen glass 21 is a plate-like member made of transparent glass, and is supported so that the surface on which the document P is placed is horizontal. The housing 22 has a hollow, substantially rectangular shape that accommodates the optical device 23 therein, and is configured to be attachable to a main body of an image forming apparatus that forms an image on a sheet. As shown in FIG. 1, the housing 22 includes a support portion 22 a that supports the platen cover 4.

The optical device 23 includes an optical system unit 24, a scanning device 25, and an imaging unit 26. The optical system unit 24 includes a light source 24a that irradiates the original P with light, a first mirror 24b that guides reflected light from the original P to the imaging unit 26, a second mirror 24c, and a third mirror 24d. .
The light source 24a emits linear irradiation light whose irradiation pattern is long in the main scanning direction (direction perpendicular to the paper surface of FIG. 1).

  The scanning device 25 moves the optical system unit 24 along the platen glass 21 in the sub-scanning direction. The scanning device 25 supports the optical system unit 24 and a moving mechanism (not illustrated) that moves the support unit (not shown). (Shown).

FIG. 2 is an enlarged view of the imaging unit 26 in FIG. FIG. 3 is a front view as seen from the back side (direction of arrow A in FIG. 1) of a CCD substrate 26d to be described later.
As shown in these drawings, the imaging unit 26 includes a mounting base 26a, an imaging lens 26b, a contact plate 26c, a CCD substrate 26d, and a pressing member 26e.

  The mounting base 26a is fixed to the housing 22 of the main body 2 or a frame (not shown), and an imaging lens 26b and a contact plate 26c are installed on a flat upper surface. The imaging lens 26b receives reflected light from the original P and forms an image with a CCD line sensor 26d2 described later on the CCD substrate 26d. The contact plate 26c is a plate-like member erected on the upper surface of the mounting base 26a, and includes an opening 26c1 for allowing reflected light to pass through. The abutting plate 26c is pressed against the back surface of the CCD substrate 26d, and positions the CCD substrate 26d in the optical axis direction of the reflected light.

The CCD substrate 26d includes a substrate 26d1 which is a plate member made of a wiring substrate, and a CCD line sensor 26d2 mounted on the substrate 26d1.
In addition to the CCD line sensor 26d2, other components are mounted on the substrate 26d1. The CCD line sensor 26d2 is a line-shaped image sensor in which the sub-scanning direction is the longitudinal direction, and is mounted at the center of the substrate 26d1. The CCD line sensor 26d2 receives the reflected light from the document P and converts it into an electrical signal.

Four pressing members 26e are attached to the back side of the contact plate 26c. The pressing member 26e has flexibility and has a claw portion at the tip, and presses the CCD substrate 26d against the contact plate 26c by sandwiching the substrate 26d1 with the contact plate 26c. To support.
The CCD substrate 26d supported by being sandwiched between the pressing member 26e and the contact plate 26c in this way is disposed so that the CCD line sensor 26d2 is exposed from the opening of the contact plate 26c, and slightly. It can be moved vertically and horizontally (in a plane orthogonal to the optical axis L of the reflected light).

  The displacement mechanism 3 includes a piezoelectric element 31 and a leaf spring 32, and displaces the CCD substrate 26d by adjusting the balance between the pressing force caused by the deformation of the piezoelectric element 31 and the urging force of the leaf spring 32. It is. The displacement mechanism 3 includes a drive device for driving the piezoelectric element 31 as necessary.

The piezoelectric element 31 is deformed according to the magnitude of the applied voltage under the control of the control device 5, and the CCD substrate 26d is moved by this deformation.
In the present embodiment, the piezoelectric element 31 includes a first piezoelectric element 31a and a second piezoelectric element 31b that are disposed below the CCD substrate 26d and spaced apart in the longitudinal direction of the CCD line sensor 26d2. . The first piezoelectric element 31a and the second piezoelectric element 31b are fixed to the upper surface of the mounting base 26a and are in contact with the lower surface of the substrate 26d1, and the CCD line sensor 26d2 is moved up and down by moving the substrate 26d1. It is moved in a direction (a direction along a plane perpendicular to the optical axis L of the reflected light and perpendicular to the longitudinal direction of the CCD line sensor 26d2). In addition, since the first piezoelectric element 31a and the second piezoelectric element 31b are arranged apart from each other, by making a difference between the displacement amount of the first piezoelectric element 31a and the displacement amount of the second piezoelectric element 31b. The CCD substrate 26d can be rotated around the optical axis L of the reflected light.
In the present embodiment, the piezoelectric element 31 includes a third piezoelectric element 31c that is disposed on the side of the CCD substrate 26d and moves the CCD line sensor 26d2 in the longitudinal direction. The third piezoelectric element 31c is fixed to the protrusion 26c2 on the back surface of the contact plate 26c and is in contact with the side surface of the substrate 26d1, and the CCD line sensor 26d2 is moved in the horizontal direction (CCD by moving the substrate 26d1. It is moved in the longitudinal direction of the line sensor 26d2.

The leaf spring 32 biases the CCD substrate 26d from the opposite side of the piezoelectric element 31. In the present embodiment, as the leaf spring 32, a first leaf spring 32a that biases the CCD substrate 26d downward from the opposite side of the first piezoelectric element 31a, and downward from the opposite side of the second piezoelectric element 31b. A second plate spring 32b for urging the CCD substrate 26d and a third plate spring 32c for urging the CCD substrate 26d from the opposite side to the side of the third piezoelectric element 31c are installed.
The first piezoelectric element 31a and the second piezoelectric element 31b are supported by the pressing member 26e. The third piezoelectric element 31c is fixed to the protrusion 26c3 on the back surface of the contact plate 26c.

  Returning to FIG. 1, the platen cover 4 is provided so as to be rotatable about a support shaft 22 b by a support portion 22 a provided at an upper portion of the housing 22 of the main body 2. That is, the platen cover 4 can be opened and closed above the platen glass 21 by being supported by the two support portions 22a. The platen cover 4 is closed when the image of the original P is read, and is open when the original P is placed on the platen glass 21.

The control device 5 controls the entire image reading device 1 of the present embodiment, and is electrically connected to the displacement mechanism 3, the scanning device 25, and the CCD line sensor 26d2.
In addition, the control device 5 stores in advance a threshold value of the received light intensity in the CCD line sensor 26d2 that is necessary for realizing high reading accuracy. Then, the control device 5 moves the CCD line sensor 26d2 by controlling the displacement mechanism 3 so that the received light intensity exceeds the threshold value stored in advance over the entire area of the CCD line sensor 26d2.

  The method for adjusting the position of the CCD line sensor 26d2 will be described below with reference to the flowchart of FIG.

First, the control device 5 sets the CCD substrate 26d to an initial position by setting a state in which no voltage is applied to the piezoelectric element 31 (step S1).
Subsequently, the control device 5 turns on the light source 24a (step S2) and detects the received light intensity of the CCD line sensor 26d2 (step S3). The control device 5 determines whether or not the received light intensity detected in step S3 exceeds a threshold value stored in advance (step S4). If the received light intensity does not exceed the threshold value, the displacement mechanism 3 is controlled to move the CCD substrate 26d (that is, the CCD line sensor 26d2). Then, the control device 5 repeats Steps S4 and S5 until the received light intensity exceeds the threshold value, and ends the position adjustment of the CCD line sensor 26d2 when the received light intensity exceeds the threshold value stored in advance.

  The control device 5 adjusts the rotation angle of the CCD line sensor 26d2 by driving the first piezoelectric element 31 and the second piezoelectric element 41b, for example, before repeating Step S4 and Step S5. Thereafter, the third piezoelectric element 41c is driven to adjust the horizontal position of the CCD line sensor 26d2.

  Further, the control device 5 stores the position of the CCD line sensor 26d2 at the time when the position adjustment of the CCD line sensor 26d2 is completed (that is, the value of the voltage applied to the piezoelectric element 31). When the image reading device 1 is powered off, no voltage is applied to the piezoelectric element 31, so the CCD substrate 26d returns to the initial position, but when the power is turned on again, the control device 5 stores it. The CCD line sensor 26d2 is moved to the position. As a result, even when the power is turned on again, the position adjustment of the CCD line sensor 26d2 can be completed in a short time.

  The image reading apparatus 1 of the present embodiment reads the image of the document P after the position adjustment of the CCD line sensor 26d2 is completed as described above. When reading the image of the original P, the original P is first placed on the platen glass 21 by the user, and then the platen cover 3 is closed by the user. Subsequently, when receiving a signal instructing execution of image reading from the operation panel or the like, the control device 5 causes the optical device 23 to acquire an image formed on the document P as image data. Then, the control device 5 outputs the acquired image data and the document P to the outside.

The image reading apparatus 1 according to the present embodiment as described above includes the piezoelectric element 31 that moves the CCD line sensor 26d2. Therefore, the position of the CCD line sensor 26d2 can be adjusted by the piezoelectric element 31.
The displacement amount (change amount) of the piezoelectric element 31 changes depending on the value of the applied voltage. Therefore, even after factory shipment, the displacement amount of the piezoelectric element 31, that is, the position of the CCD line sensor 26d2 can be easily adjusted.
Therefore, according to the image reading apparatus 1 of the present embodiment, even if the position of the CCD line sensor 26d2 is shifted due to thermal deformation or the like, the CCD line sensor 26d2 can always be moved to a region with a large amount of light, It is possible to always maintain high reading accuracy.

In the image reading apparatus 1 of the present embodiment, the piezoelectric element 31 is a first piezoelectric element that is spaced apart in the longitudinal direction of the CCD line sensor 26d2 and moves the CCD line sensor 26d2 in a direction perpendicular to the longitudinal direction. An element 31a and a second piezoelectric element 31b are provided. Therefore, the CCD line sensor 26d2 can be rotated around the optical axis L of the reflected light, and the reading accuracy can be improved.
The reason for this will be described. Since the irradiation pattern of the reflected light is a line like the irradiation pattern of the irradiation light emitted from the light source 24a, when the CCD line sensor 26d2 rotates around the optical axis L of the reflected light, the CCD The amount of displacement at the end of the line sensor 26d2 increases. Therefore, when the CCD line sensor 26d2 rotates unintentionally, the end portion of the CCD line sensor 26d2 greatly deviates from the reflected light irradiation pattern (region with high light intensity), leading to a decrease in reading accuracy. That is, when the CCD line sensor 26d2 rotates unintentionally, the reading accuracy is likely to be lowered. On the other hand, according to the image reading apparatus 1 of the present embodiment, the CCD line sensor 26d2 can be rotated around the optical axis L of the reflected light, and a decrease in reading accuracy can be prevented.

Further, the image reading apparatus 1 according to the present embodiment includes the third piezoelectric element 31 c that moves the CCD line sensor 26 d 2 in the longitudinal direction as the piezoelectric element 31.
Therefore, the CCD line sensor 26d2 can be moved not only in the vertical direction but also in the horizontal direction, and the CCD line sensor 26d2 can be moved in a wider range.

Further, the image reading apparatus 1 of the present embodiment includes a substrate 26d1 on which the CCD line sensor 26d2 is mounted, and the piezoelectric element 31 is in contact with the substrate 26d1.
For this reason, the CCD line sensor 26d2 is not directly pressed against the piezoelectric element 31, and deformation of the CCD line sensor 26d2 can be prevented.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the description of the present embodiment, the description of the same parts as those of the first embodiment is omitted or simplified.

  FIG. 2 is a longitudinal sectional view schematically showing a schematic configuration of the image reading apparatus 1A of the present embodiment. As shown in this figure, in the image reading apparatus 1A of the present embodiment, a temperature sensor 6 is installed inside a housing 22 that houses a CCD line sensor 26d2 and the like.

The temperature sensor 6 is electrically connected to the control device 5, detects the internal temperature of the housing 22, and outputs the detection result.
In the present embodiment, the control device 5 detects the CCD line sensor 26d2 described in the first embodiment when the internal temperature difference of the housing 22 changes beyond a predetermined threshold from the detection result of the temperature sensor 6. Adjust the position of. That is, in this embodiment, the control device 5 controls the piezoelectric element 31 based on the detection result of the temperature sensor 6.

  According to the image reading apparatus 1A of this embodiment, when the temperature of the space in which the CCD line sensor 26d2 is arranged changes to a certain degree, the CCD line sensor 26d2 generates reflected light due to thermal deformation of surrounding members. The position of the CCD line sensor 26d2 is adjusted by assuming that it is displaced with respect to the optical axis L. For this reason, according to the image reading apparatus 1 of the present embodiment, the CCD line sensor 26d2 is always moved with respect to the optical axis L of the reflected light even when the temperature change in the space where the CCD line sensor 26d2 is arranged is large. It can be moved to an optimum place, and high reading accuracy can always be maintained.

(Third embodiment)
FIG. 6 is a perspective view showing a schematic configuration of an image forming apparatus 100 according to the third embodiment of the present invention. As shown in FIG. 6, the image forming apparatus 100 according to the present embodiment includes an image reading device 110. The image reading device 110 reads an image of a document, and based on the read data, the image is recorded on a recording sheet. Form.

In such an image forming apparatus 100, the image reading apparatus described in the above embodiment is used as the image reading apparatus 110.
According to such an image forming apparatus 100, the image reading apparatus 110 that can always maintain high reading accuracy is provided, and it becomes possible to form a highly accurate image.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

For example, in the above embodiment, the configuration in which the three piezoelectric elements 31 are installed has been described.
However, the present invention is not limited to this, and the number of piezoelectric elements 31 can be changed.

In the above embodiment, the configuration using the CCD line sensor 26d2 as the line sensor has been described.
However, the present invention is not limited to this, and a CMOS line sensor can be used as the line sensor.

Moreover, in the said embodiment, the structure which arrange | positions the temperature sensor 6 inside the housing | casing 22 was demonstrated.
However, the present invention is not limited to this, and the temperature sensor 6 can be installed outside the housing 22.

In the above-described embodiment, the configuration has been described in which the temperature change of the space is acquired from the detection result of the temperature sensor 6 and the position of the CCD line sensor 26d2 is adjusted when the amount of the temperature change exceeds a certain threshold value. .
However, the present invention is not limited to this, and a temperature for adjusting the position of the CCD line sensor 26d2 is set in advance, and the position of the CCD line sensor 26d2 is adjusted when the set temperature is reached. good.

  DESCRIPTION OF SYMBOLS 1,1A ... Image reading device, 2 ... Main body, 3 ... Displacement mechanism, 4 ... Platen cover, 5 ... Control device (control means), 6 ... Temperature sensor, 26d ... CCD board, 26d1 ... ... substrate, 26d2 ... CCD line sensor (line sensor), 31 ... piezoelectric element, 31a ... first piezoelectric element, 31b ... second piezoelectric element, 31c ... third piezoelectric element, 32 ... leaf spring, 32a... First plate spring, 32b... Second plate spring, 32c... Third plate spring, 100... Image forming apparatus, 110. Manuscript

Claims (6)

An image reading apparatus including a line sensor that receives reflected light from a document and converts it into an electrical signal,
An image reading apparatus comprising: a piezoelectric element that moves the line sensor along a plane orthogonal to the optical axis of the reflected light.   The piezoelectric element includes a first piezoelectric element and a second piezoelectric element which are arranged apart from each other in the longitudinal direction of the line sensor and move the line sensor in a direction orthogonal to the longitudinal direction. Item 2. The image reading apparatus according to Item 1.   The image reading apparatus according to claim 1, further comprising a third piezoelectric element that moves the line sensor in a longitudinal direction as the piezoelectric element.   The image reading apparatus according to claim 1, further comprising a substrate on which the line sensor is mounted, wherein the piezoelectric element is in contact with the substrate.   A housing that houses the line sensor, a temperature sensor that detects a temperature inside or outside the housing, and a control unit that controls the piezoelectric element based on a detection result of the temperature sensor. The image reading apparatus according to claim 1.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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