JP4521914B2 - Image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus that reads an image, and more particularly, to an image reading apparatus that has a function of flowing and reading an image on a document conveyed at a predetermined speed.
[0002]
[Prior art]
Conventionally, the following two methods are well known as a method for reading an image on a document used in an image reading apparatus.
[0003]
In the first method, a document is set on a document table by a predetermined method, and the document fixed on the document table glass is scanned by a movable optical carriage so that an image on the document is transferred to the image reading unit. This is a fixed document reading method.
[0004]
The second method is a document flow reading method in which a document is conveyed at a predetermined conveyance speed and is read by a predetermined reading unit provided with a fixed optical carriage unit.
[0005]
The latter method for reading a document flow can fix the optical carriage as compared with the former method for reading a fixed document, and does not require the optical carriage to reciprocate every time. For this reason, the apparatus configuration is not complicated, and it is superior to the former original fixed reading method in that the processing speed is increased. Further, with the recent progress of digital processing technology, copying machines and the like can be read only once even when a plurality of copies are formed from the same document. In other words, once read image information is temporarily stored as digital information in a storage medium such as a computer, it becomes easy to recreate a necessary number of copied images based on the stored image information. . Also in this respect, the advantage of image reading by the flow reading method has been further increased.
[0006]
In addition, when a document includes images on both sides thereof, two optical carriages are provided along the document transport path from the viewpoint of convenience of operation and high speed in reading the images on both sides. There is also a reading device configured to read an image included on each side of the document. According to such an apparatus configuration, the images included on the front and back sides of the document conveyed along a predetermined path can be read and read almost simultaneously, so that the reading process in duplex copying of the document can be speeded up. .
[0007]
[Problems to be solved by the invention]
By the way, the conventional image reading apparatus adopting the above-described document flow reading method has the following problems.
[0008]
(1) It is difficult to position the carriage with respect to the document conveyance position, and the image is easily out of focus. In other words, it is not possible to accurately position the document reading path for flow reading and the fixed optical carriage.
[0009]
(2) In order to reduce out-of-focus blur, the optical carriage must be fixed with extremely high accuracy, making adjustment difficult and increasing the cost of the components themselves and maintenance.
[0010]
(3) The document transport path is not stable.
[0011]
These problems are common to reading apparatuses that employ the document flow reading method regardless of the number of optical carriages. In particular, in the case of a reading apparatus that includes two optical carriages, the three of the optical carriages and the originals are used. The relative position between them needs to be accurately maintained, which is more serious.
[0012]
The present invention has been made in view of such circumstances, and an object of the present invention is to perform relative positioning between the original image and the optical carriage unit with high accuracy when performing the continuous reading of the original image. An object is to provide a secured image reading apparatus.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a translucent plate material, a conveying means for conveying a document at a predetermined speed along a surface of the translucent plate material, and the document of the translucent plate material is conveyed. A first image reading means for reading the image of the original, a holding means for holding the first image reading means, and a side opposite to the side on which the original of the translucent plate is conveyed And an image reading apparatus for reading images on both sides of the conveyed document, wherein the first image reading means includes the translucent plate material. The first image reading means includes: a rotation shaft portion; and two rotation support portions that support the rotation shaft portion. The two rotation supports are connected to the holding means via a swinging mechanism. One of the rotation support portions is a rotation support portion of a round hole through which the rotation shaft portion is inserted, and the other rotation support portion is a rotation support portion of a U-shaped groove that is caught by the rotation shaft portion. The gist of the invention is that when the first image reading means reads the image of the original, the projection is in contact with the translucent plate to position the first image reading means .
[0020]
DETAILED DESCRIPTION OF THE INVENTION
(Reference Example) Hereinafter, Reference Examples in which the present invention is applied to an image reading apparatus of a digital copying machine will be described with reference to FIG.
[0021]
FIG. 1 is a side sectional view schematically showing the structure of an image reading mechanism (image reading apparatus) provided in the digital copying machine of this reference example . FIG. 7 is an enlarged side sectional view showing the vicinity of the image reading unit of the mechanism.
[0022]
As shown in FIG. 1, an image reading apparatus 100 is mounted on a flatbed image reading unit (hereinafter referred to as a flatbed unit) 1 that places and fixes a document and reads a surface image thereof, and an upper surface of the flatbed unit 1. And an automatic document feeder (ADF) 2 is formed, and a part of the flatbed unit 1 and a part of the automatic paper feeder 2 are combined to form a flow reading unit α. ing.
[0023]
The flatbed unit 1 is a mechanism for reading a surface image of a document that is placed and fixed. The flatbed unit 1 includes a reference document table glass (document table glass) 3 that is a translucent plate for placing a document on the upper surface thereof. The first platen glass is provided with a first optical carriage A which is a second image reading unit for reading a document (scanning). The first optical carriage A is connected to an endless belt (drive belt) 5, and this drive belt 5 is connected to a drive motor 6. The power of the drive motor 5 is transmitted to the first optical carriage A via the drive belt 5, so that the first optical carriage A is movable in parallel with the document table glass 3. The first optical carriage has a function of reading an image on a document placed and fixed on a platen glass, and a function of reading an image on a document being conveyed while staying at a fixed position (a flow reading function). Have both. A lamp 7 disposed on the upper surface of the carriage A is a light source for irradiating light on the document. Reflected light reflected from the document is reflected by a CCD (Charge Coupled Device) 9 by a reflection mirror 8 and a condenser lens 10. Led to. The CCD 9 is a known photoelectric conversion element that converts image information contained in light into an electrical signal. A document abutting reference plate 11 provided on the document table glass 3 is also provided.
[0024]
On the other hand, the automatic paper feeder 2 includes a document stacking tray 13 for loading and stacking documents on the top thereof. The document on the document stacking tray 13 is regulated by the document side regulating plate 12 at both sides in the transport (feed) direction. Further, the well-known document presence / absence sensor 15 recognizes the presence of the document by detecting the leading edge of the document with the lever crest. In addition, the known document length detection lever 14 also detects the length of the document. In addition, a weight 16 for pressing the leading edge of the document sent out from the document stacking tray 13 from above and a document shutter 17 for preventing the leading edge of the document from entering the separation feeding unit are provided. The pickup roller 18 has a function of sequentially feeding the stacked originals from the lowest one. The document fed out by the pickup roller 18 is conveyed to the sink reading unit α by the downstream paper feed roller 20. The separation belt 19 provided at a position facing the paper feed roller 20 across the document transport path is rotationally driven in a direction opposite to the rotation direction of the paper feed roller 20 so that the documents are surely sent out one by one. Separate the overlapping originals. The pre-registration sensor lever 21 detects the leading edge of the document and measures the timing of document loop creation. The registration roller pair 22 sends the conveyed document to the carriage A at a predetermined timing. The document leading edge detection lever 23 detects the leading edge of the document sent out by the registration roller pair 22. The document transport upper guide 24 serving as guide means is provided to face the document table glass 3 and guides the document to the first reading portion 25. The first reading portion 25 is a predetermined gap provided between the document table glass 3 and the document transport upper guide 24. The image included in the document surface (first surface) is read by the optical carriage A staying at a fixed position when the document passes through the first reading portion 25.
[0025]
The second carriage B serving as the first image reading unit is opposed to the first carriage A across the document table glass 3 in the automatic sheet feeder serving as the holding unit that holds the second carriage. It is provided at the position. In the second carriage B, the same reflection mirror and CCD as the carriage A are arranged. As described above, the second carriage B having substantially the same configuration as that of the first carriage A reads an image included in the other surface (second surface) of the document at the second reading portion 27. The second reading portion 27 is set slightly downstream of the first reading portion on the document transport path along the platen glass 3.
[0026]
The document after having passed through the first and second reading portions is discharged out of the flatbed portion 1 by the discharge roller pair 28. On the side surface of the flat bed portion 1, a paper discharge stacking tray 29 for stacking documents discharged by the discharge roller pair 28 is provided.
[0027]
2 shows the image reading apparatus 100 described with reference to FIG. 1 in a state in which the automatic sheet feeder 2 is opened with respect to the original platen glass 1 of the flatbed portion 1 and further viewed in the direction of arrow II in FIG. It is a side view.
[0028]
In FIG. 2, a member 30 is a hinge for rotatably connecting the automatic sheet feeder 2 to the flat bed portion 1, and a member 31 presses the document placed on the document table glass 3 against the document table glass 3. For the pressure plate. As described above, when the flatbed portion 1 is opened with respect to the automatic paper feeder 2, the original can be placed at a predetermined position on the original table glass 3. According to such an aspect, it is possible to use the function of only the first optical carriage A such as reading an image on a document placed and fixed on the platen glass 3, and to read the image of each document one side at a time.
[0029]
FIG. 3 is a perspective view schematically showing a configuration of a white reference plate provided for performing known shading correction when reading an image of a document in the image reading apparatus 100 of the reference example .
[0030]
As shown in FIG. 3, another platen glass provided on the lower surface of the automatic sheet feeder 2 so as to face the platen glass 3 of the flat bed portion 1 and the platen glass 3 (see also FIG. 7). 43, a part of the transport path of the document in the flow reading is formed in the gap. A white reference plate 41 that is used as a white reference in the sub-scanning direction of the document during the reading of the carriage A is provided on the opposite surface of the document table glass 3 to the surface facing the document transport path. A white reference plate 42 used as a white reference in the sub-scanning direction of the document when reading the carriage B is provided on the opposite side of the document table glass 43 from the document conveyance.
[0031]
FIG. 4 is a side view showing the image reading apparatus 100 shown in FIG. 1 with a part of the automatic paper feeder 2 opened. Such an open state is generally a form that is used to handle a so-called jam that occurs during the operation of the automatic paper feeder 2. Here, the member 35 is a jam processing lever, and the member 36 is a jam opening / closing portion that is opened when a document in a jammed state is removed.
[0032]
FIG. 5A shows a side view of the carriage B which forms a part of the automatic paper feeder 2, and FIG. 5B shows a part of the carriage B further enlarged. As shown in both figures, the carriage B held by the automatic paper feeder 2 has a configuration in which a part (projection) 26a of the frame body 26 of the carriage B directly abuts against the document table glass 3. The positioning accuracy with respect to the platen glass 3 is very high, and the positioning in the height direction is performed reliably and precisely. As shown in FIG. 8, since the document transport guide 24 is swingably connected to the carriage B, the document is guided easily and reliably to the set position with respect to the carriage B. At the same time, since a part 24a of the document conveying guide 24 directly abuts against the document glass 3, the document conveying position and the document conveying path are accurately and easily positioned between each other.
[0033]
The operation of the above configuration will be described below.
[0034]
[Original Scanning Method]
In the case of image reading on the flat bed unit 1, the automatic paper feeder 2 is opened, the document is placed on the document table glass 3, the document position is abutted against the document abutting plate 11, and the document is set.
[0035]
Next, by closing the automatic paper feeder 2, the document is pressed and fixed to the document table glass 3 by the pressure plate 31. As a result, the curling of the original is corrected and the original is brought into close contact with the original table glass 3. Thereafter, when the operator presses an original reading start button provided on an operation panel (not shown), reading of the original is started.
[0036]
First, the drive belt 5 starts to operate by the supply of power by the drive motor 6, and accordingly, the carriage A moves to a predetermined carriage home position (initial position).
[0037]
Next, in order to perform initialization (initialization) in the main scanning direction, the carriage A is moved to the white reference plate provided on the back side of the document abutting plate 11 to read the white reference. As a result, the light source 7 and the CCD 9 are corrected. Thereafter, the carriage A moves to a predetermined reading start position, and further accelerates until reaching a predetermined speed while moving from the reading start position to the document reading position. After reaching the predetermined speed, the carriage A reaches the leading edge position of the document abutted against the document abutting plate 11 while maintaining the speed. After that, the carriage A moves while maintaining a predetermined speed, and reads the document. After reading the entire surface of the document, the carriage A is reversed in the direction opposite to the reading direction by the reverse drive of the drive motor 6 and returns to a predetermined standby position.
[0038]
[Original Scanning Method]
Next, the case of the sink reading method will be described. In the case of flow reading, the original is stacked on the original stacking tray 13 of the automatic paper feeder 2. The automatic paper feeder 2 can know from the document length detection sensor 14 and the document presence / absence sensor 15 that the document is placed on the document stacking unit 13. In addition, when the operator sets the width of the document using the document side restriction plate 12, the size of the document can be known by a combination of detection with the document length detection sensor 14. When the operator presses an unillustrated document reading start button in the above-described state, the document shutter 17 that restricts the leading edge of the document is opened, and the document is moved to the document separation unit by the weight 16 and the paper feed pickup roller 18. Transport the bundle. Next, the original is separated and fed one by one by the separation belt 19 and the paper feed roller 20. After the leading edge of the document reaches the registration roller pair 22 and a pre-registration sensor 21 forms a predetermined loop, the rotation of the paper feed roller 20 is stopped. After a predetermined timing, the registration roller pair 22 starts to rotate and conveys the document. The leading edge of the conveyed document is detected by the document leading edge detection sensor 23, and the time for the document to reach the document reading position is determined. The document is guided to the first document reading point 25 by the document transport upper guide 24. The following initial operation is performed in each of the document reading carriages A and B simultaneously with the conveyance of the document. Carriage A is designated when a document is read by the automatic paper feeder 2, and performs shading correction before the document reaches the document reading point 25 after the operator presses the document reading start button.
[0039]
Next, a specific operation of the carriage A will be described.
[0040]
The carriage A turns on the lamp 7, reads the own reference 41, and performs white reference correction (known shading correction). Thereafter, it waits for the document to arrive. Similarly to the carriage A, the carriage B also ends the next shading operation before the document reaches the second reading point 27. The light source in the carriage B is turned on, the white reference of the white reference plate 42 provided at the position facing the second reading point 27 is read, and the white reference is corrected.
[0041]
After performing the shading process described above, the original reaches the first reading point 25, and images are sequentially read on one side of the original while the original is being conveyed at a predetermined conveyance speed. Further, the original reaches the second reading point 27, and the image on the other side of the original is sequentially read by the reading unit of the carriage B while being conveyed at a predetermined speed. The front end of the document passes through the second reading point 27 and is then conveyed by the discharge roller pair 28. After all the images of the document have been read, the document is discharged onto the discharge stacking tray 29.
[0042]
The above is a series of operation modes for reading both sides of a document by both the carriages A and B.
[0043]
FIG. 4 is a side view of the automatic paper feeder 2, and particularly shows how the automatic paper feeder 2 is operated and processed when an original jam occurs in the automatic paper feeder 2. is there.
[0044]
When a document jam occurs in the automatic paper feeder 2, a document jam is detected by the pre-registration sensor 21 disposed on the document conveyance path and the document leading edge detection lever 23. When the document jam is detected, the document feeding of the automatic paper feeder 2 is stopped, and the operator is notified that the document has jammed. The operator operates the jam processing lever 35 to open the jam processing opening / closing unit 36 of the automatic paper feeder 2 in the manner shown in FIG. In this state, the jammed document can be easily removed. At this time, by opening the jam processing release portion 36, the carriage B is simultaneously turned around and opened at a predetermined rotation center.
[0045]
After the operator performs the jam processing, the jam processing release portion 36 is closed. At this time, a part 26a of the carriage B hits the document table glass 3, and the height of the carriage B is accurately positioned. At the same time, a part of the document transport guide 24 hits the document table glass 3, and the document transport path can be surely secured as described above.
[0046]
FIG. 5A shows the jam processing opening / closing unit 36 of the automatic paper feeder 2 described with reference to FIG. 4 including the periphery of the connection portion with the flat bed portion 1 and the periphery of the contact portion with the platen glass 3. It is a sectional side view shown roughly. FIG. 5B is an enlarged side sectional view particularly showing the vicinity of the contact portion of the jam processing opening / closing portion 36 with respect to the platen glass 3.
[0047]
As shown in FIG. 5A, the jam processing opening / closing unit 36 and the automatic paper feeder 2 are configured to be rotatable relative to each other about an axis 60 (rotating shaft) shared by the jam processing opening / closing unit. Projections 24 a and 26 a which are part of 36, specifically, part of the document transport guide 24, are freely abutted (butted) and separated from the document table glass 3.
[0048]
Here, the jam processing opening / closing unit 36 (carriage B) is configured so that the rotation shaft 60 provided in the automatic paper feeding device 2 is jammed against the automatic paper feeding device 2 that is rotatable relative to the flat bed unit 1. By being supported by the rotation support part 62 provided in the opening / closing part 36, it is configured to be relatively rotatable.
[0049]
That is, the jam processing opening / closing portion 36 directly fixing the carriage B is swingable with respect to the flat bed portion 1 incorporating the carriage A via the two rotation support portions 62.
[0050]
According to the configuration in the present reference example, the jam processing opening / closing unit 36 directly fixing the carriage B operates so as to be swingable with respect to the flat bed unit 1 and as a part of the document conveyance guide 24 of the carriage B. The protrusions 24a and 26a provided are brought into direct contact (butting) with the original platen glass 3, so that the carriage with respect to the original platen glass 3 and eventually the carriage A (see FIG. 1) provided on the back surface thereof. B can be accurately positioned.
[0051]
That is, according to the image reading apparatus of this reference example described above, the following effects can be obtained.
[0052]
(1) An optical carriage that reads an image on the side opposite to the original on the reference platen glass side when the original is read by flow reading is configured to be able to partially abut against the reference platen glass and swing. By performing the positioning relationship between the two optical carriages A and B with the reference platen glass 3, the positioning between the optical carriages A and B can be accurately performed.
[0053]
(2) Since the swingable optical carriage B is configured to abut against the reference platen glass, the optical carriage can be positioned with high accuracy only by ensuring the accuracy of the optical carriage itself.
[0054]
(3) A document conveying guide connected to the oscillatable optical carriage B (jam processing opening / closing unit) 36 so as to be further oscillated, and a part of the document conveying guide is pushed against the reference document table glass. By configuring so as to apply, it is possible to stably secure a document transport path.
[0055]
(In the form of implementation)
Next, the implementation of the embodiment of the present invention will be described focusing on differences from the previous embodiment.
[0056]
Form of implementation relates to an image reading apparatus having substantially the same basic construction and function as in the previous reference example in linking site jam closing portion 36 (the carriage B) an automatic paper feed apparatus 2, the reference example Have different points. Thus, with regard to the configuration, function, and operation mode, overlapping description of constituent members common to the reference example is omitted here.
[0057]
FIG. 6 is a side view showing a connection mode between the automatic paper feeder provided in the image reading apparatus of the present embodiment and the jam processing opening / closing unit (carriage B). FIG. 9 is a perspective view showing a main part of the present embodiment.
[0058]
As shown in FIGS. 6 and 9, the rotary shaft 60 provided in the main body of the automatic paper feeder 2 is shared by the jam processing opening / closing unit 36 and the main body of the automatic paper feeder 2 as in the previous reference example . Is the center of rotation.
[0059]
However, in the present embodiment, the jam processing opening / closing part 36 includes a hook part 61a having a U-shaped groove as its rotation support part. Then, the hook portion 61a hooks the rotation shaft 60, whereby the jam processing opening / closing portion 36 and the automatic paper feeder 2 are engaged with each other, and are different from the reference example . In addition, the shape of the rotation support part 61b has a round hole like the previous reference example.
[0060]
In this way, the rotation shaft 60 is formed with a U-shaped groove without applying a configuration that covers the entire outer periphery of the rotation shaft 60 at one place of the connecting portion of the jam processing opening / closing portion 36 and the automatic paper feeder 2. Engaging only a part with the hook portion 61 that is provided increases the degree of freedom of relative rotation between the members 36 and 2 and the operation during contact.
[0061]
In particular, in the present embodiment, the shaft 60 and the rotation support portion 61a are not in contact with each other when the jam processing section 36 (carriage B) is in contact with the original table glass 3.
[0062]
In the present embodiment also, a part of the jam processing opening / closing part 36, specifically, the protrusions 24a and 26a, which are part of the document transport guide 24, can freely abut (abut) the document table glass 3. Spaced apart. The contact position with respect to the platen glass is located on both outer sides in the longitudinal direction of the original P conveyance area, so that passage of the original is not hindered.
[0063]
That is, according to the present embodiment, in addition to the effects of the above reference example , when the protrusions 24a and 26a are brought into contact with (abut against) the platen glass 3, they are placed on the platen glass 3 and thus on the back surface thereof. The positioning operation of the carriage B with respect to the provided carriage A (see FIG. 1) becomes flexible, and this positioning can be performed more accurately.
[0064]
【The invention's effect】
As explained above, according to the present invention,
(1) An optical carriage that reads an image on the side opposite to the original on the reference platen glass side when the original is read by flow reading is configured to be able to partially abut against the reference platen glass and swing. By positioning the two optical carriages with the reference platen glass,
(2) Since the oscillatable optical carriage is abutted against the reference platen glass, the optical carriage can be positioned with high accuracy only by securing the system of the optical carriage itself.
Therefore,
(3) A document conveying guide that is slidably connected to a swayable optical carriage, and a part of the document conveying guide is abutted against a reference document table glass. Can be stably secured.
[Brief description of the drawings]
Figure 1 is a side cross-sectional view schematically showing the structure of an image reading apparatus according to a reference example of the present invention.
FIG. 2 is a side view showing a state in which the automatic sheet feeder is opened with respect to the original platen glass of the flat bed portion in the image reading apparatus of the reference example .
FIG. 3 is a perspective view schematically showing a configuration of a white reference plate provided to perform shading correction in the image reading apparatus of the reference example .
Side view of an open- operation state to the automatic document feeder to a jam processing according to FIG. 4 the reference example.
[5] and the automatic sheet feeding apparatus according to the reference example, a side view showing the connecting mode between jam closing unit.
An automatic sheet feeding apparatus according to implementation embodiments of the present invention; FIG, side view showing a connection mode between the jam-off unit.
FIG. 7 is an enlarged side sectional view in the vicinity of an image reading unit of a reference example .
FIG. 8 is an explanatory diagram of a document conveyance guide in the reference example .
Figure 9 is a perspective view showing the principal part in the form of implementation.
[Explanation of symbols]
1 Flatbed part 2 Automatic paper feeder (holding means)
3 Platen glass (translucent plate)
4 Carriage A (second image reading means)
24 Document transport guide 26 Carriage B (first image reading means)
29 Output stacking tray

Claims (3)

A translucent plate member, a conveying unit that conveys the document at a predetermined speed along the surface of the translucent plate member, and an image of the document that is provided on a side of the translucent plate member on which the document is conveyed A first image reading unit; a holding unit configured to hold the first image reading unit; and a second image reading unit configured to read an image of the document on a side opposite to a side on which the document is conveyed of the translucent plate member. An image reading device that reads images on both sides of the conveyed document,
The first image reading unit has protrusions that come into contact with both outer sides of the width of the original in a region where the original of the translucent plate material is conveyed,
The first image reading means is swingably connected to the holding means via a rotation shaft portion and two rotation support portions that support the rotation shaft portion,
One of the two rotation support portions is a rotation support portion of a round hole through which the rotation shaft portion is inserted, and the other rotation support portion is a U-shaped groove hooked on the rotation shaft portion. A rotation support,
When the first image reading unit reads an image of the document, the projection is in contact with the translucent plate to position the first image reading unit. . The image reading apparatus according to claim 1 .
An image reading apparatus comprising: guide means attached to the first image reading means so as to be swingable, wherein a part of the guide means comes into contact with the translucent plate. The image reading apparatus according to claim 2 .
Wherein a portion of the pre-Symbol guiding means you contact the light-transparent plate, the image reading apparatus characterized by contact outside the region where the document is conveyed.

Images