JPH1051634A - Image reader and reference density member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent read image quality from being deteriorated due to a change between paper sheets by reading correction data in response to a distance between a read means and an original from a storage means thereby correcting an image signal. SOLUTION: Several kinds of white reference sheets with different thickness are fed to a printer so as to allow a scanner head cartridge 2 to acquire white correction data, and white correction data with different inter-paper conditions are stored in RAMs of at least two host computers 4. Then white correction data used corresponding to the thickness of an original to be read are read from the RAM of the computers 4 and transferred to an image processing LSI 2 being a correction means in a color scanner head cartridge 2 via a controller 3b of the printer main body as reference density data. In the image processing LSI2 2c, shading correction, correction such as binarization and other image processing are conducted for the read image signal based on the transferred white correction data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus such as a copying machine, a facsimile, a printer having a scanner function, and a reference density member used in these apparatuses.

[0002]

2. Description of the Related Art As a conventional image reading apparatus, there is an apparatus in which a scanner function is added to a recording apparatus such as a printer in addition to a general copying machine and a facsimile.

[0003] Printers having such a scanner function include a printer in which a scanner is mounted on a carriage for holding a printing unit instead of the printing unit, and a printer in which a scanner is added separately from the printing unit. Here, an ink jet printer that performs recording by discharging ink will be described as an example.

FIG. 9 is an external view of an ink head cartridge, and FIG. 10 is an external view of a scanner head cartridge. By replacing the scanner head cartridge 2 with the ink head cartridge 1 mounted on the carriage of the printer, the printer can function as an image reading device. Therefore, the shape of the scanner head cartridge 2 is very similar to that of the ink head cartridge 1 so as not to hinder the mounting on the carriage.

FIG. 11 is a block diagram showing a configuration of a printer having such a scanner function. First, a description will be given of a case where the device functions as a recording device, that is, a general printer. Record data such as characters or images is transferred from the host computer (PC) 4 to the interface (I / F).
The data is transferred to the controller 3b under the control of the PC 4 and the CPU 3d through 3c. The controller 3b processes the received recording data into data to be recorded on recording paper by the ink head cartridge 1.

Further, the controller 3b sends recording data to the ink head cartridge 1 through the carriage head terminal 3a under the control of the CPU 3d, and records characters or images on the recording paper. The operation at this time will be described with reference to FIG. 12 showing the printing mechanism of the printer.

In the same figure, 5 is a carriage on which an ink head cartridge is mounted, 6 is a CPU 3d of FIG.
A platen that supports the recording paper fed by a driving mechanism controlled by the controller 3b and the motor driver 3i and serves as a recording table.

[0008] The carriage 5 is arranged movably along the guide shaft 7. At the time of recording, the scanner head cartridges 2 are mounted on the carriage 5 and are conveyed along the original surface for reading.

The movement of the carriage 5 is controlled by a CPU 3d, a controller 3b, and a motor driver 3e.
This is performed by driving the R motor 3g. The paper detection sensor 3h detects whether a recording paper or a document for reading is set on the platen 6. Further, the CR detection sensor 3f detects whether or not the carriage 5 is at the start position. As described above, the image data is recorded on the recording paper.

Next, the case where the present apparatus is used as an image reading apparatus will be described with reference to FIG. FIG. 13 is an internal configuration diagram of the scanner head cartridge 2. The scanner head cartridge 2 is attached to the carriage 5 as described above. First, it is necessary to use the scanner head cartridge 2 to capture white correction data, which is a reference when reading an image, and transfer the data to the PC 4 for storage.
Such a method of acquiring white correction data includes a platen 6
There is a method of reading the white reference piece 20 provided on the side of, and a method of feeding and acquiring a white reference sheet. Here, the case of using the latter white reference sheet will be described.

First, the white reference sheet is fed to the printing mechanism in the same manner as the original to be read. Then, the light source 2b attached to the scanner head cartridge 2 irradiates the surface of the white reference sheet 9 via the lens 10 from an oblique direction,
The reflected light enters the sensor 2a via the mirror 12 and the lens 8, and is converted into an image signal.

The white correction data thus obtained is
In the block diagram of FIG. 11, the output signal of the sensor 2a is amplified by an image processing LSI 2c to an optimal level to be handled by a subsequent analog / digital converter (hereinafter referred to as an A / D converter), and then the A / D signal is amplified. Input to the converter.
After performing predetermined image processing on the converted digital data, the digital data is transferred to the printer main body 3 via the carriage head terminal 3a of the inkjet printer.

The white correction data is transferred to the host computer 4 through a path reverse to the flow of the recording data at the time of recording.
And stored in the built-in RAM. That is, data is sent from the image processing LSI 2c to the host computer 4 via the carriage head terminal 3a, the controller 3b, and the interface 3c. At this time, the controller 3
b transfers the image data received from the image processing LSI 2c in a form easy to send through the interface 3c or in a form easy to handle by the host computer 4 under the control of the CPU 3d.

The white correction data stored in the RAM in the host computer 4 is transferred to the scanner head cartridge 2 along the reverse path when reading the original image, and is used as reference data when processing the image data. Is done. That is, the digital image data input to the image processing LSI 2c is subjected to shading correction, binarization correction, and other image processing based on the white correction data transferred from the host computer 4. The flow of image data transfer at this time is the same as the case of taking in white correction data.

Next, the operation of the mechanical unit at the time of image reading is different from the operation at the time of recording, in which the color scanner head cartridge scans the same original surface three times. That is, for reading by the color scanner head cartridge, the RGB three-color LEDs 2b provided inside are sequentially turned on,
A method of forming a color image by reading the same document surface for each color is adopted.

That is, in a state in which the original for image reading is set on the platen 6, the carriage 5 mounts the color scanner head cartridge 2 and turns on one of the three colors of LEDs, for example, Red, to light up one line. The image is read along the document surface, and then the same operation is repeated three times for Green and Blue. The switching control of each light source is performed by the image processing LSI 2c in the color scanner head cartridge under the control of the CPU 3d. The flow of the data processing repeats the above-described contents three times each time reading is performed for each of the RGB colors.

When the image data for one line has been captured in this way, the CPU 3d, the controller 3b,
By feeding the LF motor 3j controlled by the motor driver 3e, the paper is fed to the next reading line, and the same operation is repeated. At this time, the movement of the carriage 5 is performed by driving the CR motor 3g controlled by the CPU 3d, the controller 3b, and the motor driver 3e as in the case of recording.

As described above, the printer can function as a color image reading device.

[0019]

However, the color scanner head cartridge which can make the above-described printer function as a serial type image reading apparatus has the following drawbacks.

First, since the positioning of the original cannot be performed on the image side, the relative distance (hereinafter referred to as the sheet interval) from the scanner head cartridge to the original surface changes depending on the thickness of the original to be read. In some cases, the distance was different between when the correction data was obtained and when the document was read.
Here, in this apparatus, since the light source irradiates the reading surface from an oblique direction as described above, if the paper interval is different, the difference in the amount of irradiation light on the reading surface becomes remarkable, and the density change and the reading output are caused.
Color unevenness sometimes occurred.

Further, the change between the sheets is affected by the paper transport mechanism of the printer, and the above-described change in the sheet interval becomes large at the leading end of the original to be read. Unevenness and the like were particularly likely to occur.

[0022]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an image reading apparatus according to claim 1 has a reading means for reading an original and outputting an image signal; Storage means for storing a plurality of correction data corresponding to the distance between the reading means and the document for correcting the image signal output from the means, and correction data corresponding to the distance between the reading means and the document. Correction means for reading from the storage means and correcting the image signal.

According to a seventh aspect of the present invention, there is provided an image reading apparatus, comprising: reading means for reading an original and outputting an image signal; and a plurality of reading means for correcting the image signal output from the reading means and corresponding to the thickness of the original. The image processing apparatus further includes a storage unit that stores the correction data, and a correction unit that reads the correction data corresponding to the thickness of the document from the storage unit and corrects the image signal.

A reference density member according to a thirteenth aspect is a reference density member for obtaining reference density data serving as a reference for correction of an image signal by reading by a reading means. In order to acquire a plurality of different reference data according to the distance, means for changing the distance from the reading means is provided.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment The configuration of a printer functioning as an image reading apparatus according to the present embodiment is the same as that shown in FIGS. 9 to 11, and a description thereof will be omitted. FIG. 1 is an internal configuration diagram of the scanner head cartridge 2 which is the reading unit shown in FIG. In FIG. 1, light emitted from a light source 2 b illuminates an original surface 9 from an oblique direction via an illumination lens 10. The light reflected on the original surface passes through the mirror 12 and the lens 8 to be transmitted to the sensor 2a.
Incident on. The incident imaging light is converted into an image signal by the sensor 2a. Here, since the light source is configured to irradiate the document surface obliquely, as shown in FIG. 1, the paper interval (the relative distance between the scanner head cartridge 2 and the document surface) is a to b or c. , An error occurs between the irradiation position of the light source and the reading position.

FIG. 2 shows the absolute value of the output obtained by the sensor 2a between such sheets. Assuming that the output when the sheet interval is a is the maximum value, when the sheet interval becomes b, an error occurs by Δ × b between the irradiation position of the light source and the reading position of the sensor as shown in FIG. The output obtained by will drop. This is the same when the sheet interval is c, and the error in this case is Δ × c.

As described above, by reading the white reference sheet or the white reference piece as the reference density member with the sheet interval a, the white correction data as the reference density data is obtained, and the sheet interval when the original is actually read is obtained. Is b or c because the thickness of the document is different from that of the white reference sheet, the read image becomes dark or the color balance is lost, which causes deterioration of the read image quality.

FIGS. 3 and 4 are schematic diagrams of the printing / reading mechanism. The original 9 to be read is supplied by paper feed rollers 13a and 13b.
Is fed to the reading position while being supported by the platen 6, and further discharged by the discharge rollers 14a and 14b. Here, the paper feed roller 13a and the paper discharge roller 14a have a structure in which the original is pressed against the paper feed roller 13b and the paper discharge roller 14b by the action of a spring, and is movable in a direction orthogonal to the original conveyance direction according to the thickness of the original. ing. In such a structure, as shown in FIG. 4, the original is supported by the platen 6 at the bottom in the reading unit. Therefore, when originals having different thicknesses are fed, The interval will change. Therefore, in the present embodiment, white correction data is obtained by preparing white reference sheets having different thicknesses in advance.

That is, several types of white reference sheets having different thicknesses are fed to a printer, white correction data is acquired by the scanner head cartridge 2, and at least two or more white correction data having different sheet spacing conditions are provided by the host computer 4. Is stored in a RAM (not shown) which is a storage means in the inside.
Then, the white correction data to be used corresponding to the thickness of the document to be read is read out from the RAM in the host computer 4,
Image processing LS as correction means in the color scanner head cartridge 2 via the controller 3b of the printer body
It is transferred to I2c as reference density data. Image processing L
In SI2c, shading correction, binarization correction, and other image processing on the read image signal are performed based on the transferred white correction data.

With this configuration, the user can
A host computer 4 for inputting the thickness of the original to be read
It is possible to prevent the quality of the read image from deteriorating due to the change between the sheets only by specifying. In the above description, it is described that a plurality of white reference sheets need to be inserted in order to store a plurality of types of white reference data. However, for example, as shown in FIG. 18b
When the white reference sheet 18 having a step portion provided with a step portion 19 in the center is used, the white reference sheet 18 is fed to a printer and white correction data is obtained in a portion with / without a step. Between papers in one paper feed operation
Since it is possible to obtain different types of white correction data, it is possible to prevent a decrease in read image quality due to a change between sheets without increasing the load on the user. In this method, even when the white reference piece 20 is provided beside the platen 6 and the white correction data is acquired by reading the white reference piece 20, it can be realized only by providing a step on the white reference piece.

Further, in the present embodiment, the thickness of the original to be read by the user is input. However, the present invention is not limited to this. For example, a detecting means for automatically detecting the thickness of the original is provided, and Alternatively, the host computer 4 as the control means may select appropriate white reference data. As the detecting means, for example, if the movement of the paper feed roller or the paper discharge roller shown in FIGS. 3 and 4 is detected, the thickness of the document can be detected.

<< Second Embodiment >> In the first embodiment, a method for preventing a decrease in image quality when the sheet interval changes due to the influence of the document thickness has been described. A case where the sheet interval changes due to the influence of the transport mechanism will be described.

FIGS. 6 to 8 are side views of the printing / reading mechanism, which are conveyed by paper feed rollers 15a and 15b and paper discharge rollers 16a and 16b as in FIGS. Further, the paper feed roller 15b and the paper discharge roller 16b are pressed against opposing rollers by the action of springs, and have a structure in which the paper can be moved downward when paper is fed.

Referring to FIG. 8, the feature of this mechanism is that the paper feed roller 15b and the paper discharge roller 16b are structured to escape downward in the figure when the paper is fed. The paper interval from the head surface to the paper surface becomes constant regardless of the paper thickness. However, as shown in FIG. 7, in reading the leading edge of the original where the paper has not been fed to the paper discharge rollers 16a and 16b after the paper has been fed,
The leading end of the document falls on the surface of the platen 6, and the sheet interval changes. Therefore, when it is desired to start reading from the leading edge of the document, density unevenness or color unevenness occurs at the leading end of the read image.

Therefore, a means for using white correction data different between papers as in the first embodiment is effective. In other words, the white correction data used until the leading edge of the document hits the paper discharge roller 16 may be stored separately from the normally used white correction data.

More specifically, as in the first embodiment, first, a plurality of white correction data are stored in the host computer 4 using a plurality of white reference sheets or a stepped white reference sheet. After obtaining the white correction data,
The original to be read is fed to the reading unit. Then, the reading of the document image is started as described above. At this time,
A few lines for reading the leading edge of the document are sent from the host computer 4 to the image processing LSI of the scanner head cartridge 2.
The correction data when the paper interval is far is transferred to 2c and read, and the leading edge of the document is fed to the paper discharge roller 16, and after the paper interval is stabilized, white correction data when the paper interval is short, that is, In the case of a stepped white reference sheet, the data obtained when the white correction data is obtained on the surface portion having no step is subjected to image processing L.
The data is transferred to SI2c for reading. As a result, it is possible to prevent the read image quality from deteriorating even when the sheet interval at the leading end of the sheet is not stable due to the influence of the sheet transport mechanism of the printer.

<< Third Embodiment >> In the first embodiment, in order to correspond to the type of original thickness for reading white correction data,
Although it has been described that the correction is performed a plurality of times, the white correction data between at least two types of paper is stored in the host computer 4 and
By converting the difference between the two data with the thickness based on white, it is possible to use the data as stricter white correction data. Therefore, it is necessary to increase the white correction data that can be selected by the user according to the thickness of the document to be read. Can be.

For example, each white correction data is obtained using two white reference sheets, and if the original to be read has an intermediate thickness between the two white reference sheets, two white correction data are used. A value obtained by averaging the white correction data may be used. In the above-described embodiment, the white correction data is stored in the host computer, but may be stored in a memory in the scanner cartridge.

Further, in the above three embodiments, an example in which a scanner cartridge is added to an ink jet printer has been described. However, the present invention is not limited to this embodiment, and an image is read with a certain interval from a document to be read. It goes without saying that a similar effect can be obtained by applying the present invention to a device having a mechanism.

[0041]

As described above, in the image reading apparatus according to the first aspect, reading means for reading an original and outputting an image signal, and the reading means for correcting the image signal output from the reading means. A storage unit storing a plurality of correction data corresponding to a distance between the unit and the document, and reading the correction data corresponding to a distance between the reading unit and the document from the storage unit to correct the image signal. Correction means. With this configuration, even when the document cannot be positioned on the image surface side, the read image quality such as a change in image density and color unevenness due to a change in the distance between the reading unit and the document. Can be prevented from decreasing.

According to a seventh aspect of the present invention, there is provided an image reading apparatus, comprising: reading means for reading an original and outputting an image signal; and a plurality of reading means for correcting the image signal output from the reading means and corresponding to the thickness of the original. Storage means for storing correction data,
Correction means for reading correction data corresponding to the thickness of the document from the storage means and correcting the image signal. With this configuration, even when the document cannot be positioned on the image surface side, the read image quality such as image density change and color unevenness due to the change in the thickness of the document to be read is reduced. Can now be prevented.

According to a thirteenth aspect of the present invention, the reference density member is a reference density member for obtaining reference density data serving as a reference for correction of an image signal by reading by a reading means. In order to acquire a plurality of different reference data according to the distance, means for varying the distance from the reading means is provided. Thus, a plurality of different reference data according to the distance between the reading means and the reading position can be obtained by reading one reference density member.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a scanner head cartridge.

FIG. 2 is a diagram illustrating a relationship between a sheet interval and an output level.

FIG. 3 is a side view of a printing / reading mechanism.

FIG. 4 is a configuration block diagram of a printer.

FIG. 5 is an external view of a stepped white reference sheet.

FIG. 6 is a side view of a printing / reading mechanism.

FIG. 7 is a side view of a printing / reading mechanism.

FIG. 8 is a side view of a printing / reading mechanism.

FIG. 9 is an external view of an ink head cartridge.

FIG. 10 is an external view of a scanner head cartridge.

FIG. 11 is a configuration block diagram of a printer having a scanner function.

FIG. 12 is a perspective view of a printer mechanism.

FIG. 13 is a configuration diagram of a scanner head cartridge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink head cartridge 2 Scanner head cartridge 2a Sensor 2b LED 2c Image processing LED 3 Inkjet printer main body 3a Carriage head terminal 3b Controller 3c Interface 3d CPU 4 Host computer 5 Carriage 6 Platen 7 Guide shaft 8 Imaging lens 9 Document 10 Condenser Lens 11 LED board 12 Mirror 13a, 13b, 15a, 15b Paper feed roller 14a, 14b, 16a, 16b Paper discharge roller 17 Paper feed guide member 18 Stepped white reference sheet 19 Stepped portion 20 White reference piece

Claims (18)

[Claims] A reading unit configured to read an original and output an image signal; and a plurality of correction data corresponding to a distance between the reading unit and the original for correcting an image signal output from the reading unit. An image reading apparatus, comprising: a storage unit that stores therein; and a correction unit that reads correction data corresponding to a distance between the reading unit and the document from the storage unit and corrects the image signal. 2. An apparatus according to claim 1, further comprising: input means for inputting a distance between said reading means and said document; and said correction means reading correction data from said storage means in accordance with the distance input by said input means. An image reading apparatus, comprising: a control unit configured to perform control as described above. 3. The apparatus according to claim 1, further comprising: detecting means for detecting a distance between the reading means and the document; and correcting means for correcting the correction data from the storage means in accordance with the distance detected by the detecting means. And a control unit for controlling so as to read the image. 4. The reading device according to claim 1, wherein the reading unit has a light source that irradiates the document, and a sensor that converts light from the document irradiated by the light source into an image signal, The image reading apparatus according to claim 1, wherein the light source irradiates the document from an oblique direction. 5. The image reading apparatus according to claim 1, wherein the storage unit stores shading correction data of the image signal. 6. An image reading apparatus according to claim 1, wherein said storage means stores white reference data of said image signal. 7. Reading means for reading a document and outputting an image signal; storage means for storing a plurality of correction data corresponding to the thickness of the document for correcting the image signal output from the reading means; An image reading device comprising: a correction unit that reads correction data corresponding to the thickness of the document from the storage unit and corrects the image signal. 8. The control according to claim 7, further comprising: input means for inputting the thickness of the document, and control so that the correction means reads correction data from the storage means in accordance with the thickness input by the input means. And an image reading device. 9. The control device according to claim 7, further comprising: a detecting unit configured to detect a thickness of the document, and the correction unit reading the correction data from the storage unit according to the thickness detected by the detecting unit. An image reading apparatus comprising: 10. The reading device according to claim 7, wherein the reading unit includes a light source that irradiates the document, and a sensor that converts light from the document irradiated by the light source into an image signal, The image reading apparatus according to claim 1, wherein the light source irradiates the document from an oblique direction. 11. An image reading apparatus according to claim 7, wherein said storage means stores shading correction data of said image signal. 12. An image reading apparatus according to claim 7, wherein said storage means stores white reference data of said image signal. 13. A reference density member for obtaining reference density data serving as a reference for correction of an image signal by reading by a reading unit, wherein a plurality of different reference data according to a distance from the reading unit. A reference density member provided with a means for varying a distance from the reading means in order to obtain a reference density. 14. The reference density member according to claim 13, wherein a means is provided for providing a step to the reference density member to vary the distance from the reading means. 15. The reference density member according to claim 13, wherein a means for varying the distance from the reading unit by partially changing the thickness of the reference density member is provided. 16. The apparatus according to claim 13, wherein the reference density data is obtained by reading the reference density member by the reading unit in the same manner as a document. Reference density member. 17. The reference density member according to claim 13, wherein the reference density data is shading correction data of the image signal. 18. The reference density member according to claim 13, wherein the reference density data is white reference data of the image signal.