JP2011166604A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus in which paper jamming in a reading position is reduced, and also a jammed original document is removed easily in a sheet-through system using a contact image sensor. <P>SOLUTION: The image reading apparatus reads the images of an original document D to be guided one by one in a reading position B through a contact image sensor 40. Original document guide members such as guide plates 51, 52 or the like are placed to oppose a reading glass 41 provided on the sensor 40. The original document guide members are energized with a given strength in a direction towards the sensor 40 by a coil spring 62, and also may be swung downward with a shaft 70 as a pivot against the energizing strength. An original document D is guided between the reading glass 41 and a feeding guide members. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus, and more particularly to an image reading apparatus that optically reads an image of a document conveyed one by one during conveyance.

  As an image reading apparatus for optically reading an image of a document, there are a platen set method for reading an image of a document placed on a platen glass and a sheet-through method for reading an image of a document conveyed one by one during conveyance. , Each alone or in combination. The sheet-through method has advantages in reducing the size of the apparatus, reducing the cost, increasing the speed of reading, and, in turn, the productivity of printing on a copying machine.

  In recent years, a first surface (front surface) image of a document is read at a first reading position using an optical system that reads the document image by a platen set method, and a second image (back surface) is provided by a contact image sensor provided at the second reading position. The so-called dual scan type is provided which reads the image of (2). With the dual scan type, images on both sides can be read with a single pass of the document, higher print productivity can be obtained, and the frequency of document jams can be halved.

  Since the contact image sensor installed at the second reading position is small, it contributes to miniaturization of the image reading apparatus. However, since the depth of focus is shallow, it is necessary to convey the second surface at the second reading position while keeping the distance from the sensor constant at all times. In addition, it is necessary to set a narrow gap between the reading glass arranged in the contact image sensor and the conveyance guide member arranged facing the reading glass, and the possibility of occurrence of a paper jam increases. In addition, there is a risk of damaging the reading glass when removing a document jammed in a bellows shape.

  In Patent Document 1, a projection is provided on a contact image sensor, and a document conveyed to the projection is brought into contact / bent to pass through a reading position while maintaining a certain distance from the glass surface. An image reader is described. Patent Document 2 describes a double-sided image reading device that stabilizes image quality by elastically pressing a guide member toward a reading glass at an image reading position to suppress lifting of a conveyed document.

JP 2004-48149 A Japanese Patent No. 3883907

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image reading apparatus that can suppress the occurrence of a paper jam at a reading position and can easily remove a jammed document in a sheet-through system using a contact image sensor. is there.

An image reading apparatus according to one aspect of the present invention is
First reading means and second reading means for optically reading a first surface image of a document conveyed one by one at a first reading position during conveyance and a second image at a second reading position during conveyance. In an image reading apparatus comprising:
The second reading means is a contact image sensor;
A conveyance guide member is disposed to face the contact image sensor,
The conveyance guide member is elastically biased toward the contact image sensor with a predetermined amount of force, and can be displaced in a direction away from the contact image sensor against the bias force;
It is characterized by.

  In the image reading apparatus, at the second reading position, the document is regulated and conveyed between the reading glass of the contact image sensor and the conveyance guide member, and the image on the second surface is read. By restricting the document with the conveyance guide member, it can be reliably read by the contact image sensor having a shallow depth of focus. The conveyance guide member is elastically urged toward the contact image sensor with a predetermined amount of force and can be displaced in a direction away from the contact image sensor against the urging force. When the sheet is pressed, the conveyance path is slightly widened. Therefore, the occurrence of a paper jam at the second reading position is suppressed, and when a paper jam occurs, the jammed document can be easily taken out. Further, even when the original is jammed in a bellows shape, the reading glass is hardly damaged when taken out.

  In the image reading apparatus, it is preferable that the conveyance guide member is attached to a cover member, and the cover member can be moved in a direction away from the contact image sensor. The second reading position can be greatly opened, and the jammed document can be easily taken out.

  According to the present invention, in the sheet-through method using the contact image sensor, occurrence of a paper jam at the reading position can be suppressed, and a jammed document can be easily removed.

It is a schematic block diagram which shows the principal part of the image reader which is one Example. It is sectional drawing which shows the structure in the 2nd reading position in the said image reading apparatus. It is sectional drawing which shows the state which open | released the conveyance guide member in the 2nd reading position. It is explanatory drawing which shows the means to lock the cover of a conveyance guide member.

  Embodiments of an image reading apparatus according to the present invention will be described below with reference to the accompanying drawings.

(Schematic configuration of image reading apparatus, see FIG. 1)
As shown in FIG. 1, the image reading device includes a platen set method for reading an image of a document placed on the platen glass 10, and a sheet-through method for reading an image of a document conveyed by an automatic document conveying device 20. A reading optical system 30 and a contact image sensor 40.

  The reading optical system 30 is known per se, and includes a lamp 33, mirrors 34, 35, and 36, and an imaging lens and an image sensor (CCD) (not shown). In order to read a document image by the platen set method, the lamp 33 and the mirror 34 are mounted on the first slider 31, and the mirrors 35 and 36 are mounted on the second slider 32, respectively, and are movable in the direction of arrow Z. Reading the image on the first surface (front surface) of the document by the sheet-through method is performed in a state where the optical system 30 is stationary at the first reading position A. The contact-type image sensor 40 reads the image on the second side (back side) of the document in the sheet-through method at the second reading position B.

  The automatic document feeder 20 includes a document placement tray 21, a paper feed roller 22, a separation roller 23, a registration roller 24, and conveyance rollers 25, 26, 27, and 28. The document D is placed on the tray 21 with the first side facing up, fed from the top layer by the feed roller 22, and fed one by one by the separation roller 23, and passes through the registration roller 24. The conveying roller 25 first conveys the reading glass 37 and the image on the first surface is read by the optical system 30 at the first reading position A.

  Next, the original D is conveyed to the second reading position B by the conveying roller 26, and in the double-sided reading mode, the image on the second side is read by the contact image sensor 40. At this time, the document D is conveyed between the reading glass 41 of the contact image sensor 40 and a conveyance guide member described in detail below. Thereafter, the document D is discharged to a discharge tray (not shown) by the transport rollers 27 and 28.

  The contact image sensor 40 has a conventionally well-known configuration, and includes a light source lamp, a CCD sensor, and a lens array (not shown) built in the housing, and a reading glass 41 is fixed to the front side of the housing. Yes.

(Document guide mechanism at the second reading position, see FIGS. 2 to 4)
The contact-type image sensor 40 has a shallow depth of focus. In the second reading position B, the document D is brought close to the reading glass 41 and is in non-contact with the reading glass 41 as much as possible within the range of the depth of focus. It is necessary to convey the second surface of D and the reading glass 41 while maintaining a substantially constant distance.

  For this reason, in this embodiment, as shown in FIG. 2, guide plates 51 and 52 that function as conveyance guide members and a semicircular member 53 in section are attached to the bracket 60 so as to face the reading glass 41 of the contact image sensor 40. . The bracket 60 is attached to the cover member 65. The semicircular member 53 has a white surface, is used for shading correction when reading an image, and functions as a reading background portion. Further, a brush 54 is attached to the semicircular member 53, and foreign matters such as dust attached to the surface of the reading glass 41 are cleaned by the brush 54 as the semicircular member 53 rotates.

  The conveyance roller pair 26 is disposed closer to the upstream side in the conveyance direction d than the contact image sensor 40, and one roller 26 a is attached to the cover member 65. In addition, one roller 27 a of the transport roller pair 27 disposed closer to the downstream side in the transport direction d than the contact image sensor 40 is also attached to the cover member 65.

  The bracket 60 and the cover member 65 are swingable in the vertical direction with a support shaft 70 provided in the apparatus main body as a fulcrum. The bracket 60 is elastically biased toward the contact image sensor 40 by the lower end of the coil spring 62 provided in the recess 61 being in contact with the cover member 65. The spacer 63 provided on the bracket 60 abuts on the surface of the reading glass 41, whereby the distance between the conveying guide member (guide plates 51 and 52, semicircular member 53) and the surface of the reading glass 41, that is, conveying the document D. Space will be regulated. The bracket 60 swings downward with the support shaft 70 as a fulcrum against the spring force of the coil spring 62 when the conveyed document D comes into contact therewith. This swinging position is regulated by the end 60 a of the bracket 60 coming into contact with the cover member 65. The spacers 63 are arranged on both sides of the conveyance path so as not to disturb the conveyance of the document D.

  That is, the conveyance guide member including the bracket 60 can swing about the support shaft 70 while being elastically biased toward the contact image sensor 40 with a predetermined amount of force of the coil spring 62. Usually, the conveyance guide member guides the conveyance of the document D while being positioned by the spacer 63, and the guide surface is such that the second surface of the document D is within the reading range of the contact image sensor 40 (within the depth of focus range). Preferably there is.

  When the document D is thick paper or the leading edge and the trailing edge are curled downward, the conveyance guide member is pressed downward and swings with the support shaft 70 as a fulcrum, thereby slightly opening the conveyance path. As a result, the document D is prevented from being jammed, and when the leading end is clogged at the second reading position B, the leading end is not easily deformed into a bellows shape. However, it is preferable that the second surface of the document D to be transported guides within the range of the focal depth of the contact image sensor 40 even when the transport guide member swings downward as described above.

  The amount of force that urges the conveyance guide member by the coil spring 62 is preferably an amount that does not swing due to the weight of the conveyance guide member or the bracket 60 and vibration from the outside. Further, it is preferable that the amount of force is smaller than the pressing force by the document having the maximum thickness within the allowable range for passing paper. Specifically, the amount of force of the coil spring 62 is preferably larger than about 5.5N and smaller than about 14.5N. By setting the force amount of the coil spring 62 within this range, the conveyance guide member is not swayed by its own weight or the like, and the conveyance path is set within a range in which the reading image is not deteriorated by the pressing force during conveyance of the document D. Can be spread.

  On the other hand, when a paper jam occurs at the second reading position B, as shown in FIG. 3, the cover member 65 is swung downward with the support shaft 70 as a fulcrum, thereby conveying at the second reading position B. The route can be greatly opened. As a result, the jammed document can be easily removed.

  Incidentally, as shown in FIG. 4, a claw member 66 is rotatably attached to the cover member 65 with a pin 67 as a fulcrum in a state where the claw member 66 is urged in the direction of arrow c by a torsion spring (not shown). The cover member 65 is locked at a predetermined position when the claw member 66 engages with a lock piece 71 fixed to the apparatus main body. In this locked state, the spacer 63 comes into contact with the surface of the reading glass 41 and the conveyance guide member is positioned at the document guide position. On the other hand, by rotating the claw member 66 in the direction opposite to the arrow c to release the engagement with the lock piece 71, the cover member 65 can be swung downward.

(Other examples)
The image reading apparatus according to the present invention is not limited to the above embodiment, and can be changed within the scope of the gist thereof.

  For example, the image reading apparatus may have various forms, and may be one in which a contact image sensor is installed instead of the optical system 30. Further, the details of the automatic document feeder can adopt any configuration.

  In the above-described embodiment, the conveyance guide member such as the guide plate 51 and the bracket 60 are slidably disposed on the support shaft 70 common to the cover member 65, but it is not necessarily required to be coaxially slidable. For example, the conveyance guide member such as the guide plate 51 and the bracket 60 may be displaceable in a direction linearly away from the contact image sensor 40. Further, the second reading position B may be arranged upstream of the first reading position A in the document transport direction.

  As described above, the present invention is useful for an image reading apparatus, and is particularly excellent in that the occurrence of a paper jam at a reading position can be suppressed and a jammed document can be easily removed.

DESCRIPTION OF SYMBOLS 20 ... Automatic document conveying apparatus 26 ... Pair of conveyance rollers 40 ... Contact type image sensor 41 ... Reading glass 51, 52 ... Guide plate 60 ... Bracket 62 ... Coil spring 63 ... Spacer 65 ... Cover member A ... First reading position B ... First 2 Reading position D ... Original

Claims (9)

First reading means and second reading means for optically reading a first surface image of a document conveyed one by one at a first reading position during conveyance and a second image at a second reading position during conveyance. In an image reading apparatus comprising:
The second reading means is a contact image sensor;
A conveyance guide member is disposed to face the contact image sensor,
The conveyance guide member is elastically biased toward the contact image sensor with a predetermined amount of force, and can be displaced in a direction away from the contact image sensor against the bias force;
An image reading apparatus.   The position where the transport guide member is displaced in the direction away from the contact image sensor by the transported document is a position where the second surface of the transported document is guided within the reading range of the contact image sensor. The image reading apparatus according to claim 1.   3. The force according to claim 1, wherein the amount of force for elastically urging the conveyance guide member is smaller than a pressing force by a document having a maximum thickness within a sheet passing allowable range. Image reader.   4. The force according to claim 1, wherein the amount of force for elastically urging the conveyance guide member is an amount of force that the conveyance guide member does not displace due to its own weight and external vibration. Image reader.   The image reading apparatus according to claim 1, wherein the conveyance guide member is capable of swinging in a direction away from the contact image sensor.   The spacer member which determines the space | interval of the conveyance path | route between the said conveyance guide member and the said contact | adherence image sensor is attached to the said conveyance guide member, The Claim 1 thru | or 5 characterized by the above-mentioned. Image reader.   The said conveyance guide member is attached to the cover member, This cover member can be slid in the direction away from the said contact | adherence image sensor, The one of Claim 1 thru | or 6 characterized by the above-mentioned. Image reader.   8. The image reading apparatus according to claim 1, wherein a pair of conveying rollers is arranged closer to the upstream side in the document conveying direction than the contact image sensor. 9. The image reading apparatus according to claim 8, wherein one roller of the conveying roller pair is attached to the cover member.

Images