JP2004112545A - Image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading device for eliminating mismatching of white waveforms caused by a floating original in a transport route. <P>SOLUTION: The image reading device reads an image from an original while it is transported. The image reading device comprises mechanisms 3, 4, 5, and 6 for transporting the original, and mechanisms 10 and 11 for freely stopping a transport roller 5 at the egress side. Moreover, the image reading device has a function for being able to sample shading correction data of different transport location at multiple positions for storage and processing. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading apparatus using a contact sensor, such as a facsimile, in particular.
[0002]
[Prior art]
In Patent Document 1, prior to reading a document, shading correction data is collected in a state where a shading sheet is fixed to a reading unit (contact sensor) in advance. By repeating this operation a plurality of times, a plurality of pieces of shading data are collected.
[0003]
[Patent Document 1]
JP 10-257317 A
[Problems to be solved by the invention]
The above problem is solved by performing correction based on the plurality of shading data. However, there is a problem that the document has to be set many times repeatedly to capture the shading data. Further, if dust is attached when the shading sheet is fixed, NG (defective) data is collected.
[0005]
In a conventional image reading device, in order to use a low-cost contact sensor, LED pitch unevenness, which is a characteristic characteristic of a low-cost contact sensor, is used by a product mechanism. Must be matched (otherwise, an LED pitch unevenness image is likely to appear when copying in the photo mode).
[0006]
It is desirable that the shading correction and the actual paper passing be as close as possible to the glass surface of the contact sensor.However, since various types of paper are passed, a certain gap is required between the white reference plate and the contact sensor. It has become.
[0007]
Also, due to the difference in the thickness of the paper when the paper is passed, the white reference plate tends to rise more easily in the thick paper when the document is passed. Furthermore, the distance from the glass surface of the contact sensor on the front end side and the rear end side of the document may differ depending on the document passing path.
[0008]
In Patent Literature 1, the shading data to be referred to is measured a plurality of times, but the plurality of measurements is performed by measuring and storing a plurality of pieces of shading data with a shading sheet fixed in advance. Therefore, according to this method, it is necessary to take in shading data a plurality of times to take in shading data a plurality of times.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an image reading apparatus that eliminates a mismatch between white waveforms when a document rises due to a conveyance path.
[0010]
[Means for Solving the Problems]
In order to solve the above problem, in the invention according to claim 1, in an image reading apparatus that reads an image from a document while transporting the document, a mechanism for transporting the document is provided, and a transport roller on an exit side can be freely set. The most important feature is an image reading apparatus having a mechanism for stopping and having a function of collecting, storing, and processing shading correction data at different positions at different positions.
[0011]
According to the second aspect of the present invention, in an image reading apparatus that reads an image from a document while transporting the document, a mechanism for transporting the document, a mechanism for freely stopping a transport roller on an entrance side, and a transport position are further provided. The most important feature is an image reading apparatus having a function of collecting, storing, and processing shading correction data at different locations.
[0012]
According to a third aspect of the present invention, in an image reading apparatus that reads an image from a document while transporting the document, the image reading apparatus includes a mechanism for transporting the document, and has a function of measuring and processing a transport position when the document is passed, Further, an image reading apparatus characterized by having a switching function depending on the thickness of paper is the most main feature.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a layout near a contact sensor in an image reading apparatus. In the figure, in this image reading apparatus, spacers (not shown) are attached to both ends of a contact sensor 1 and a white pressure plate 2 is provided thereon. There is a gap for document conveyance between the contact sensor 1 and the white pressure plate 2 due to the spacer. Further, it comprises a transport roller 3 on the entrance side, a driven roller 4, a transport roller 5 on the exit side, and a driven roller 6 for transporting the document to the image reading apparatus.
[0014]
FIG. 2 is a schematic view showing a state in which shading is performed by normal conveyance. Normally, the shading sheet 7 is sandwiched between the conveyance roller 3 on the entrance side, the driven roller 4 and the conveyance roller 5 on the exit side, and the driven roller 6, and the gap between the white pressure plate 2 and the reading unit (contact sensor) 1 The transport position differs depending on the slackness of the shading sheet 7. When the shading data is sampled in a state in which the shading data is brought into close contact with the reading unit 1 due to the difference in the transport position, a pitch unevenness image is likely to occur.
[0015]
FIG. 3 is a schematic diagram showing a bent state of the shading sheet during shading adjustment. The shading sheet 7 is bent like a shading sheet 8 indicated by a dotted line to collect shading data.
[0016]
FIG. 4 is a block diagram showing a first embodiment of a circuit for collecting shading data used in the image reading apparatus according to the present invention. For ease of explanation, reference is made to the layout of the image reading apparatus in FIG.
[0017]
In the present invention, in order to remove the complexity at the time of shading sampling, shading sampling can be performed automatically by the operation of the drive motor 10. Further, by changing the place where the shading data is collected by the operation of the drive motor 10, it is possible to prevent erroneous collection of the shading data.
[0018]
In FIG. 4, in addition to the original detection sensor 9 and the drive motor 10, a shading data collecting circuit includes an entrance sensor 13, an exit sensor 14 for monitoring the driving state of the exit side conveyance roller 5, and a signal from the exit sensor 14. , A motor drive controller 11 for controlling ON / OFF of the drive motor 10 and a solenoid 12.
[0019]
FIG. 5 is a block diagram showing a second embodiment of a circuit for collecting shading data used in the image reading apparatus according to the present invention. In the second embodiment, a signal is sent to the motor drive controller 11 by a motor pulse measurement unit 15 instead of the exit sensor 14 in the first embodiment.
[0020]
Although not shown, it is also possible to configure so that a signal is sent to the motor drive controller 11 by the motor pulse measurement unit 15 instead of the entrance sensor 13 of FIG.
[0021]
FIG. 6 is a flowchart showing a first example of shading data collection. Referring to FIGS. 1 and 4, the shading plate 7 is set (S1), and when the shading mode is started at the time of shading data collection (S2), the contact sensor 1 is turned on. Is read, and shading data A is collected (S3).
[0022]
The shading data A is stored in an SRAM (not shown) (S4). After that, the drive motor 10 is driven (S5), and the exit-side transport roller 3 is engaged with the entrance-side transport roller 3, the driven roller 4, the exit-side transport roller 5, and the driven roller 6 while the shading sheet 7 is engaged. 5. The driving of the driven roller 6 is stopped (the driving motor 10 is stopped) (S7), the contact sensor 1 is turned on, and the output of the central portion of the shading sheet 7 is read (S8). And the shading data B is stored in the SRAM (S9).
[0023]
Thereafter, the transport roller 3 and the driven roller 4 on the entrance side are slightly driven (S10), the transport roller 3 and the driven roller 4 on the entrance side are stopped (S11), and then the transport roller 3 and the driven roller 4 on the entrance side are moved. The sheet is slightly driven to make the sheet like the shading sheet 8 in FIG. 3 slack.
[0024]
In this state, the contact sensor 1 is turned on to read the output of the central portion of the shading sheet 7 (S12). In this state, the shading data C is fetched, and the shading data C is stored in the SRAM (S13).
[0025]
Further, the same operation is repeated, that is, the transport roller 3 and the driven roller 4 on the entrance side are slightly driven (S14), and the transport roller 3 and the driven roller 4 on the entrance side are stopped (S15). Is turned on to read the output of the central portion of the shading sheet 7 (S16). In this state, the shading data D is fetched, and the shading data D is stored in the SRAM (S17). Thereafter, the conveying roller 3 and the driven roller 4 on the entrance side are driven (S18), the shading sheet 7 is discharged (S19), and the driving motor 10 is stopped (S20).
[0026]
The shading data is fetched in a state where the slack state of the document is changed, that is, in a state where the distance of the document from the reading unit 1 is changed. The captured shading data is stored in an SRAM (not shown).
[0027]
FIG. 7 is a characteristic diagram showing shading data. The shading data stored in the SRAM is based on the four pieces of shading data A, B, C, and D as shown in FIG. Compare the output data and apply shading data correction.
[0028]
FIG. 8 is a flowchart showing correction of shading data at the time of document conveyance.
The correction coefficient of the shading data is calculated by a calculation unit (not shown) based on the flow shown in FIG.
[0029]
Referring to FIG. 8, an original is set (S21), copying is started (S22), and drive motor 10 is started (S23). The contact sensor 1 is turned on, the output of the document is read (S24), and the shading data of the SRAM is called (S25).
[0030]
After reading the output of the original in S24 and calling the shading data of the SRAM in S25, the calculation unit (not shown) corrects all the pixels in the main scan based on the original data and the shading data A, B, C, and D. A coefficient is calculated (S27), and shading is performed (S26).
[0031]
Conventionally, the drive motor 10 is driven by a signal from the document detection sensor 9 and stopped by a signal from a document discharge sensor (not shown).
[0032]
FIG. 9 is a flowchart showing a second example of shading data collection. When the shading plate 7 is set (S31) and the shading mode is started at the time of shading data collection (S32), the contact sensor 1 is turned on, and in that state, the output of the white pressure plate 2 is read and the shading data A is collected. (S33).
[0033]
The shading data A is stored in an SRAM (not shown) (S34). After that, the drive motor 10 is driven (S35), and the entrance side conveyance roller 3, the driven roller 4, the exit side conveyance roller 5, and the driven roller 6 are engaged with the shading sheet 7 (S36). The driving of the roller 3 and the driven roller 4 is stopped (the driving motor 10 is stopped) (S37).
[0034]
The contact sensor 1 is turned on to read the output of the central portion of the shading sheet 7 (S38). In this state, the shading data B is fetched, and the shading data B is stored in the SRAM (S39).
[0035]
Thereafter, the transport roller 5 and the driven roller 6 on the exit side are slightly driven in reverse (S40), and the driving of the transport roller 5 and the driven roller 6 on the exit side are stopped (the drive motor 10 is stopped) (S41). Of the sheet such as the shading sheet 8 of FIG. In this state, the contact sensor 1 is turned on, the output of the central portion of the shading sheet 7 is read (S42), the shading data C is fetched, and the shading data C is stored in the SRAM (S43).
[0036]
Further, the same work (S44, S45, S46) is repeated to take in the shading data D (S47). Thereafter, the conveying roller 5 and the driven roller 6 on the exit side are driven (S48), the shading sheet 7 is discharged (S49), and the driving motor 10 is stopped (S50).
[0037]
The shading data is taken in a state where the slack state of the document is changed, that is, in a state where the distance of the document from the reading unit 1 is changed.
[0038]
The captured shading data is stored in an SRAM (not shown), and the original is conveyed based on the four shading data A, B, C, and D as shown in FIG. The shading data is corrected by comparing with the output data of the main scanning line at that time.
[0039]
A third example of shading data collection will be described. The mode is determined when the shading data A, B, C, and D collected in the first example or the second example are preliminarily stored in the SRAM, such as a document with a thin shading data D and a document with a thick shading data B, as an example. And save.
[0040]
When the actual original is conveyed, a drive motor (not shown) is driven, and the original is engaged with the conveying roller 3, the driven roller 4, the conveying roller 5, and the driven roller 6 on the entrance side. The driving of the transport roller 5 and the driven roller 6 is stopped (a driving motor not shown in the figure is stopped), and in this state, the data of the original is taken in.
[0041]
Thereafter, the transport roller 3 and the driven roller 4 on the entrance side are slightly driven to bring the original such as the shading sheet 8 in FIG. 3 into a slack state. In that state, the data of the original is taken in.
[0042]
A calculation unit (not shown) compares the data of the two originals with the shading data A, B, C, and D already collected in the first example (or the second example), The optimal mode is automatically selected.
[0043]
【The invention's effect】
As described above, according to the first aspect, when a plurality of pieces of shading data are fetched, the amount of deflection of the shading sheet is changed and the data is collected by controlling the drive motor to thereby collect the shading data in advance. Labor) and variations due to human work can be eliminated.
[0044]
In addition, since the data capture position is changed by motor control, the influence of dust can be eliminated, problems due to erroneous data collection can be eliminated, and LEDs based on illumination depth can be corrected based on multiple shading data. Control that does not cause image abnormality such as pitch unevenness can be performed.
[0045]
According to the second aspect, focusing on the deflection of the document due to the linear velocity difference between the transport roller on the entrance side and the transport roller on the exit side during sheet transport, stopping the transport roller on the entrance side and changing the deflection of the document. Thus, by collecting the shading data in a state in which the conveyance height of the document is changed, it is possible to eliminate the inconsistency of the white waveform due to the rising of the document due to the conveyance path.
[0046]
According to the third aspect, at the time of document transport, the document transport height is estimated by calculating from the deflection at the time of document transport according to claim 1 or 2, and a switching mode based on the height is provided, thereby providing a transport path. This can eliminate the inconsistency of the white waveform due to the rising of the original due to the above.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a layout near a contact sensor in an image reading apparatus.
FIG. 2 is a schematic diagram illustrating shading during normal transport.
FIG. 3 is a schematic diagram illustrating a flexed state of a shading sheet during shading adjustment.
FIG. 4 is a block diagram showing a first embodiment of a shading data collecting circuit used in the image reading apparatus according to the present invention.
FIG. 5 is a block diagram showing a second embodiment of a shading data collection circuit used in the image reading apparatus according to the present invention.
FIG. 6 is a flowchart illustrating a first example of shading data collection.
FIG. 7 is a characteristic diagram showing shading data.
FIG. 8 is a flowchart illustrating correction of shading data during document conveyance.
FIG. 9 is a flowchart illustrating a second example of shading data collection.
[Explanation of symbols]
1 Reading unit (contact sensor)
3. Inlet side transport roller (mechanism for transporting the original)
4 Inlet driven rollers (mechanism for transporting originals)
5 Exit side transport roller (mechanism for transporting the original)
6 Exit driven rollers (mechanism for transporting originals)
10. Drive motor (mechanism for stopping transport rollers freely)
11 Drive motor controller (mechanism for stopping transport rollers freely)

Claims (3)

In an image reading device that reads an image from a document while transporting the document, a mechanism for transporting the document is provided, a mechanism for freely stopping a transport roller on an exit side is provided, and shading correction data having different transport positions is provided at a plurality of locations. An image reading apparatus having a function of collecting, storing, and processing the data by using a computer. In an image reading device that reads an image from a document while transporting the document, a mechanism for transporting the document is provided, a mechanism for freely stopping the transport roller on the entrance side is provided, and shading correction data having different transport positions is provided at a plurality of locations. An image reading apparatus having a function of collecting, storing, and processing the data by using a computer. An image reading device that reads an image from a document while transporting the document, has a mechanism to transport the document, has a function to measure and process the transport position when the document is passed, and a function to switch according to the thickness of the paper An image reading device comprising:

Images