JP3661401B2 - Image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus that reads an image using a contact image sensor, a CCD (Charged Coupled Device) or the like, such as a facsimile machine or a scanner, and in particular, an image reading suitable for maintaining high-quality reading. It relates to the device.
[0002]
[Prior art]
In an image reading apparatus such as a facsimile apparatus or a scanner that reads an image using a contact image sensor, a document to be read is transported by a transport roller or the like, and passed over the reading surface of the contact image sensor. The image of the original is read by the contact image sensor.
When reading an image in this way, in order to maintain the reading quality, it is necessary to convey the document as close as possible to the reading surface of the contact image sensor.
[0003]
Also, in an image reading apparatus such as a facsimile machine or a scanner that reads an image using a CCD, in a type in which a document to be read is conveyed by a conveyance roller or the like, a glass provided at a predetermined reading position is used. Therefore, it is necessary to convey the original to a certain extent on the reading surface.
[0004]
In addition, when using either a contact image sensor or a CCD, an image reading apparatus that transports a document to be scanned with a transport roller or the like is provided with a “white reference plate” at the scanning position, so-called shading correction. Is done.
The document passes between the white reference plate and the reading surface (contact image sensor or glass).
[0005]
Documents to be read include those handwritten with a ballpoint pen and a fountain pen, and those corrected with a correction liquid (white). When such a document in which the ink or the correction liquid is not completely dried is carried in, the ink or the correction liquid adheres to the contact image sensor or the glass.
As a result, even when reading a normal document, the image of ink or correction liquid adhering to the image reading surface such as a contact image sensor or glass is read, and the image cannot be read normally. Further, if the stain is ink (black), the shading correction is not normally performed.
[0006]
As a technique considering the gap between the original and the reading surface (contact image sensor, glass, etc.), for example, there is one described in Japanese Patent Laid-Open No. 2-305169. In this technique, high-quality image reading can be stably performed by rotating the document regulating member (6) regardless of the thickness of the conveyed document. Further, the above document describes that dirt adhering to the back side of the document is not transferred to the white roller or the white pressing member.
[0007]
For example, in the above document, by providing a guide spacer (6e) on the document regulating member (6), a gap is formed between the document and the reading position. The image is being read. However, in this case, since the back side of the document is in contact with the white background portion (6d) of the document regulating member (6), the dirt on the back side of the document is actually contaminated with the white background portion (6d) of the document regulating member (6). ).
[0008]
Further, in the case of a thick document, the surface of the document is conveyed in contact with the contact sensor or glass, so that dirt on the surface of the document adheres to the contact image sensor or glass.
Further, the image reading position (5a) is composed of the document holding position of the sheet feeding means composed of the sheet feeding roller (2) and the sheet feeding roller (3), and the sheet discharging roller (8) and the sheet discharging roller (9). Since it is provided at a position on the opposite direction side (in this case, on the upper side) from the height of the straight line connecting the document holding position of the delivery means, even a thin document is actually in close contact with the contact image sensor or glass Thus, as described above, it is impossible to “make sure that dirt attached to the back side of the document is not transferred to the white roller or the white pressing member”.
[0009]
[Problems to be solved by the invention]
The problem to be solved is that the conventional technology cannot prevent the stain on the original from adhering to the image reading surface or the white reference plate.
An object of the present invention is to provide an image reading apparatus that can solve these problems of the prior art and stably read a high-quality image.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the image reading apparatus of the present invention is configured such that the passage when passing over the reading surface of the document is separated from the reading surface, and the surface of the document contacts the reading surface such as the sensor surface or the glass surface. In addition, when the original passes through the reading surface, only the leading and trailing edges of the original are brought into contact with the reading surface.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a first embodiment of the configuration of the image reading apparatus according to the present invention.
In FIG. 1, 1 is a contact image sensor, 2 is a reading surface, 3 is a spacer, 4 is a white reference plate, 5 is a spring, 6 is a transport roller (front), 7 is a transport roller (rear), 8 is a cleaning roller, 9 is a cleaning felt, 10 is a cleaning roller, and 11 and 12 are guide members.
[0012]
The white reference plate 4 is pressed against the reading surface 2 made of glass or the like by a spring 5, but is in contact with the spacer 3 in the configuration shown in FIG. 3 mm) is provided between the white reference plate 4 and the reading surface 2. The original is fed into and passed through this gap by the transport roller (front) 6, and the image is read by the contact image sensor 1 during that time. Then, the original after the image is read is sent out by a transport roller (rear) 7.
[0013]
In this way, before the document is fed to the reading surface 2 by the transport roller (front) 6, the front and back surfaces of the document are cleaned by the cleaning roller 8 and the cleaning roller 10 in the image reading apparatus of this example. As a result, the cleaning roller 8 and the cleaning roller 8 can be cleaned even when the front and back surfaces of the document have dirt that can be transferred to the white reference plate 4 or the reading surface 2 such as ink or correction liquid (white) that has not completely dried. The roller 10 removes the white reference plate 4 and the reading surface 2 from the original.
[0014]
Further, the dirt transferred from the surface of the document to the cleaning roller 8 is wiped off by the cleaning felt 9. In addition, the cleaning felt 9 shall be replaced | exchanged suitably.
FIG. 2 is a perspective perspective view showing a configuration example of the reading surface portion in FIG.
The spacer 3 is provided at an end on the reading surface 2, that is, at a position outside the width of the original that passes through. The white reference plate 4 is pressed onto the spacer 3 by a spring 5, and a document path (paper path) is formed in a gap corresponding to the height of the spacer 3.
[0015]
In the configuration of the image reading apparatus shown in FIG. 1, since the cleaning roller 8, the cleaning felt 9, and the cleaning roller 10 are provided, the size of the apparatus increases and the cost increases. Such a problem is addressed by adopting the configuration shown in FIG.
[0016]
FIG. 3 is a sectional view showing a second embodiment of the configuration according to the present invention of the image reading apparatus of the present invention.
The image reading apparatus of this example is obtained by removing the cleaning roller 8, the cleaning felt 9, and the cleaning roller 10 from the image reading apparatus in FIG.
This configuration is the same as that of the conventional image reading device, but the image reading device of this example is characterized by the configuration of the transport roller (front) 6, the transport roller (rear) 7, and the guide members 11 and 12. It is
[0017]
That is, the transport rollers (front) 6 and the transport rollers (rear) 7 have their respective document holding positions (heights) above the contact surface between the white reference plate 4 and the spacer 3. 6 and the transport roller (rear) 7 are attached, and the guide members 11 and 12 are also attached so as not to feed the document in the direction of the reading surface 2.
A in the figure indicates the difference in height between the path connecting the transport roller (front) 6 and the transport roller (rear) 7 and the reading surface 2 of the contact image sensor 1.
[0018]
With this configuration, the document fed from the transport roller (front) 6 is guided along the inclined portion of the white reference plate 4 and is in contact with the white reference plate 4 on the reading surface 2. Pass the upper side.
That is, since the image of the document is read with the surface of the document not in contact with the reading surface 2, dirt such as ink or correction liquid (white) that has not dried completely adheres to the surface of the document (the surface to be read). Even so, the dirt is not transferred to the reading surface 2.
[0019]
In this configuration, when the thickness of the document is thicker than the thickness of the spacer 3 (0.3 mm), the document is conveyed by pushing up the white reference plate 4, so that the surface contacts the reading surface 2. There is a risk that dirt on the surface of the document is transferred to the reading surface 2.
In order to deal with such a problem, the configuration shown in FIG. 4 is adopted.
[0020]
FIG. 4 is a sectional view showing a third embodiment of the configuration according to the present invention of the image reading apparatus of the present invention.
In the image reading apparatus of this example, the spacer 3 of the image reading apparatus in FIG. 3 is changed to a spacer 3a having a thickness of, for example, 0.5 mm to 0.8 mm, and the conveying roller (front) ) 6 and the conveying roller (rear) 7 and the mounting positions of the guide members 11 and 12 are also changed.
[0021]
Thus, by providing the thick spacer 3a, the document path is further formed in a direction away from the reading surface 2 of the contact image sensor 1, so that even a document having a thickness exceeding 0.3 mm can be obtained. , Transfer of dirt can be prevented.
Note that the thickness of the spacer 3 a is determined in accordance with the resolution of the contact image sensor 1.
[0022]
In this configuration, since the gap between the reading surface 2 and the white reference plate 4 formed by the spacer 3 a becomes large, dust tends to accumulate on the reading surface 2, and the dust is caused to adhere to the contact image sensor 1. There is a risk of being read.
In order to deal with such a problem, the configuration shown in FIG. 5 is adopted.
[0023]
FIG. 5 is a sectional view showing a fourth embodiment of the configuration according to the present invention of the image reading apparatus of the present invention.
The image reading apparatus of this example is provided with a solenoid 13 and a stopper 14 and is configured to change the space between the white reference plate 4 and the reading surface 2 in two stages in accordance with the document conveyance timing.
[0024]
That is, FIG. 5A shows a state where the solenoid 13 is turned on, and the plunger 13a of the solenoid 13 is drawn into the solenoid 13 body. In this state, the white reference plate 4 is pressed onto the spacer 3 by the spring 5, and the gap between the white reference plate 4 and the reading surface 2 becomes about 0.3 mm as usual. In the standby state of the image reading apparatus, dust is prevented from staying on the reading surface 2 by turning off the solenoid 13 as described above.
[0025]
FIG. 5B shows a state in which the solenoid 13 is turned off, and the plunger 13a of the solenoid 13 is fed from the solenoid 13 body by a spring (not shown), and the white reference plate 4 is pushed up. It has become. In this state, the white reference plate 4 is pushed up to a position where it abuts against the stopper 14, and the gap between the white reference plate 4 and the reading surface 2 is, for example, about 0.7 mm as in the example of FIG. . By setting this state when the image reading apparatus reads an image, it is possible to avoid transfer of dirt (undried ink or white correction liquid) on the original to the reading surface 2.
[0026]
Note that it is advantageous in terms of power consumption to keep the solenoid 13 in the off state while the image reading apparatus is on standby. For this purpose, the position of the solenoid 13 is changed or a connection member is provided. You can deal with it.
Further, FIG. 5B is set to the standby state of the image reading apparatus, and once the image reading operation is started, the state is temporarily changed to the state of FIG. 5A, and then returned to the state of FIG. 5B again. It is also possible to control.
[0027]
That is, while the image reading apparatus is on standby, the solenoid 13 is turned off to be in the state shown in FIG. In this case, the gap between the white reference plate 4 and the reading surface 2 becomes large, and dust and dust are likely to stay on the reading surface 2. Therefore, at the start of the image reading operation, the solenoid 13 is turned on to the state shown in FIG. In this state, the leading edge of the document is passed through and conveyed while the leading edge of the document is in contact with the reading surface 2. By this operation, dust and dirt on the reading surface 2 are removed at the leading edge of the document.
[0028]
Then, at the timing when the image surface of the document begins to pass over the reading surface 2, the solenoid 13 is turned off and the white reference plate 4 is pushed up to the position of the stopper 14 by the plunger 13a of the solenoid 13, and the surface of the document becomes the reading surface. Do not touch 2. Further, the solenoid 13 is turned on at the timing when the image surface of the document finishes passing over the reading surface 2, that is, when the trailing edge of the document begins to pass over the reading surface 2, and the white reference plate 4 is moved to the spacer 3. The position is lowered to a contact position, and the reading surface 2 is cleaned at the trailing edge of the document.
[0029]
By adjusting the gap between the white reference plate 4 and the reading surface 2 of the contact image sensor 1 by turning on / off the solenoid 13 as described above, the adjustment can be made only in two stages, large and small. The size of the gap cannot be changed in a minute manner corresponding to the use situation of the operator such as the thickness and hardness of the ink or the properties of the ink. In order to deal with such a problem, it is effective to adopt the configuration shown in FIG.
[0030]
FIG. 6 is a cross-sectional view showing a fifth embodiment of the configuration of the image reading apparatus according to the present invention.
The image reading apparatus of this example is provided with a motor 15 and a cam 16 instead of the solenoid 13 and the stopper 14 in FIG. 5, and the white reference plate 4 is controlled by controlling the motor 15 by the control circuit in the next FIG. And the reading surface 2 are configured to change finely.
[0031]
FIG. 7 is a block diagram showing a configuration example of a control circuit for controlling the operation of the motor in FIG.
In FIG. 7, 71 is an operation unit for inputting an operation start instruction from an operator, 72 is a main control unit ("CPU" in the figure) that performs computer processing in a storage program system by a CPU (Central Processing Unit) or the like. 73) is a spacer control unit that controls the start of the motor 15 based on the control from the main control unit 72 and adjusts the size of the space between the white reference plate 4 and the reading surface 2 in FIG.
[0032]
The operator sets the size of the space between the white reference plate 4 and the reading surface 2 shown in FIG. 6 according to the use situation such as the thickness and hardness of the document or the nature of the ink via the operation unit 71. To do. The main control unit 72 notifies the set value to the spacer control unit 73 and activates the spacer control unit 73. The spacer control unit 73 adjusts the rotation amount based on the set value notified from the main control unit 72 and rotates the motor 15.
[0033]
The operation of the motor 15 and the cam of FIG. 6 fixed to the motor 15 by the control operation of the control circuit will be described with reference to FIG.
When the motor 15 rotates corresponding to the value set by the operation unit 71 in FIG. 7, the cam 16 is rotated by a gear fixed to the rotation shaft of the motor 15.
The cam 16 is in contact with the white reference plate 4 urged by the spring 5, and the white reference plate 4 is held at a position corresponding to the shape of the portion of the cam 16 in contact.
[0034]
In the cam 16 having the shape shown in FIG. 6, the rotation of the motor 15 in the clockwise direction (arrow A in the figure) causes the cam 16 to rotate in the counterclockwise direction (arrow B in the figure). 4 is lowered, and the space between the white reference plate 4 and the reading surface 2 is narrowed. Conversely, the space between the white reference plate 4 and the reading surface 2 is widened by the counterclockwise rotation of the motor 15.
[0035]
7 can be easily controlled to turn on / off the solenoid 13 in FIG. 5 instead of the motor 15, and the control operation in this case will be described with reference to FIG.
FIG. 8 is a flowchart showing an example of operation control processing of the solenoid in FIG.
[0036]
When an image reading operation of the image reading apparatus is started and a preset time Ta has elapsed (step 801), that is, immediately before the reading target portion of the document comes on the reading surface 2 of the contact image sensor 1 in FIG. The solenoid is turned off (step 802). As a result, the solenoid is in the state shown in FIG. 5B, and the space between the white reference plate 4 and the reading surface 2 is widened.
[0037]
In this state, the original is read, but the original is conveyed while being in contact with the white reference plate 4 and is not in contact with the reading surface 2 of the contact image sensor 1. As a result, even if dirt such as ink or white correction liquid that has not completely dried adheres to the reading surface (front surface) of the document, the dirt is not transferred to the reading surface 2.
[0038]
When the document reading target portion passes through the reading surface 2 of the contact image sensor 1 of FIG. 5, that is, when a preset time Tb has elapsed (step 803), the solenoid is turned on (step 804). As a result, the solenoid is in the state shown in FIG. 5A, the space between the white reference plate 4 and the reading surface 2 is narrowed, and the standby state is entered.
[0039]
As described above with reference to FIGS. 1 to 8, in the image reading apparatus according to the present embodiment, before the document reaches the image capturing position (reading surface 2 of the contact image sensor 1), the front surface and the back surface of the document. The cleaning roller 8, the cleaning felt 9, and the cleaning roller 10, and the passage when passing through the image capturing position of the original are separated from the image capturing position (the reading surface 2 and the white reference plate 4). And the document surface does not contact the reading surface such as the sensor surface or glass surface, or when the document passes the image capture position, only the leading and trailing edge portions of the document are scanned. The white reference plate 4 is moved up and down by the solenoid 13, the motor 15, and the cam 16.
[0040]
With such a configuration, it is possible to avoid dirt such as ink or correction liquid (white) that has not completely dried on the original from adhering to the image reading surface or the white reference plate.
In addition, this invention is not limited to the Example demonstrated using FIGS. 1-8, In the range which does not deviate from the summary, various changes are possible.
[0041]
【The invention's effect】
According to the present invention, it is possible to prevent dirt such as ink and correction liquid (white) that has not completely dried from adhering to an image reading surface or a white reference plate, and to stably read a high-quality image. Can be done.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of a configuration according to the present invention of an image reading apparatus of the present invention.
2 is a perspective perspective view showing a configuration example of a reading surface portion in FIG. 1. FIG.
FIG. 3 is a sectional view showing a second embodiment of the configuration according to the present invention of the image reading apparatus of the present invention.
FIG. 4 is a sectional view showing a third embodiment of the configuration according to the present invention of the image reading apparatus of the present invention.
FIG. 5 is a cross-sectional view showing a fourth embodiment of the configuration according to the present invention of the image reading apparatus of the present invention.
FIG. 6 is a cross-sectional view showing a fifth embodiment of the configuration according to the present invention of the image reading apparatus of the present invention.
7 is a block diagram illustrating a configuration example of a control circuit that performs operation control of the motor in FIG. 6;
8 is a flowchart showing an example of operation control processing of the solenoid in FIG. 5;
[Explanation of symbols]
1: contact image sensor, 2: reading surface, 3, 3a: spacer, 4: white reference plate, 5: spring, 6: transport roller (front), 7: transport roller (rear), 8: cleaning roller, 9: Cleaning felt, 10: Cleaning roller, 11, 12: Guide member, 13: Solenoid, 13a: Plunger, 14: Stopper, 15: Motor, 16: Cam, 71: Operation unit, 72: Main control unit, 73: Spacer control Department.

Claims (3)

In the image reading apparatus that reads an image from the original while conveying the original, a conveyance path for the original is formed so that the original is conveyed away from the reading surface of the original by a predetermined distance. An image reading apparatus comprising: means ; and means for bringing the document conveyance path close to the reading surface while predetermined portions of the leading edge and the trailing edge of the document pass on the reading surface . In an image reading apparatus that reads an image from the original while conveying the original, the original is formed so that the original is conveyed a predetermined distance away from the reading surface of the original. The white reference plate is pressed against the reading surface on the reading surface, and the document transported through the conveyance path is pressed against the reading surface by the white reference plate, and the pressing means presses the document. Spacer means for contacting the white reference plate on the reading surface and forming a predetermined gap between the reading surface and the white reference plate, and predetermined portions at the leading and trailing edges of the original are read. An image reading apparatus comprising means for bringing the document transport path close to the reading surface while passing over the surface . 3. The image reading apparatus according to claim 1, further comprising means for controlling a distance between the reading surface and the document transport path based on an instruction from an operator.

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