JP2004088605A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus for absorbing variation of scale plates and for automatically erasing copy out of a script by leaving minimum margins. <P>SOLUTION: The image formation apparatus comprises an image read means having a scale plate at a position around a read region when reading a script, an image processing means for performing image processing on image data obtained by reading by the image read means, and a control means for controlling changes of a certain image processing region as a range where the image processing means performs the image processing on the image data. The control means makes the image read means read a maximum readable region including the scale plate in a state without a script as examination scanning, and determines a rectangular region of a maximum range not including the scale plate in a read result by the examination scanning as the image processing region. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in an image forming apparatus provided with an image reading unit (scanner) having a scale plate at any position around a reading area when reading a document.
[0002]
[Prior art]
FIG. 5 is a perspective view showing an external configuration of a general image forming apparatus. In FIG. 5, reference numeral 12 denotes a platen glass on which a document is to be placed as a document reading area. An optical system (light source, mirror, lens, CCD, etc.) described below is arranged below the platen glass 12 so that an image of a document placed on the platen glass 12 can be read. .
[0003]
Reference numeral 13 denotes a scale plate which is provided at a peripheral end of the platen glass 12 and is a means for regulating the position of the original by abutting the original. Reference numeral 11 denotes a platen cover for covering the entire platen glass 12 during normal scanning.
[0004]
Reference numeral 14 denotes an operation display unit for operating and displaying the image forming apparatus, and includes a power switch, a copy start switch, a numeric keypad, and a liquid crystal display unit also serving as a touch panel. Reference numeral 15 denotes a paper discharge unit that outputs a recording sheet on which an image formed by an image forming unit (print engine) is output for an image read by an image reading unit described below.
[0005]
FIG. 6 is a configuration diagram showing a cross-sectional configuration of a general image forming apparatus. Here, the image surface of the original is illuminated by the light source 114a, and the reflected light is reflected by the mirror 114b, 114c, 114d via the imaging optical system (lens) 114e to form an image on the light receiving surface of the CCD 111 serving as a photoelectric conversion unit. tie.
[0006]
Here, the image reading unit 110 is composed of the light source 114a, mirrors 114b, 114c, 114d, an optical system having an imaging optical system 114e and a CCD 111, and an optical system driving unit (not shown).
[0007]
In FIG. 6, when the document is placed on the platen glass 12 with the reading surface facing down, the optical system scans while moving along the platen glass 12 to perform reading (scanning).
[0008]
The image data read by the scanning in the image reading unit 20 in this manner is subjected to predetermined image processing in the image processing unit, and then is supplied to the print engine 140 to execute image formation.
[0009]
On the other hand, the recording paper is fed out and fed by a paper feed roller from a paper feed cassette on which the recording paper is stacked. The fed recording paper approaches the photosensitive drum 141 serving as an image carrier.
[0010]
Image data is input from the image processing unit to the exposure unit 140a, and a laser beam corresponding to the image data is emitted from the laser diode in the exposure unit 140a onto the photosensitive drum 141 to form an electrostatic latent image. The electrostatic latent image is developed by the developing unit 143 to form a toner image on the photosensitive drum 141.
[0011]
This toner image is transferred to the recording paper p by the transfer section 144 below the photosensitive drum 141. Then, the recording paper p that is in contact with the photosensitive drum 141 is separated by the separation unit 145. The recording paper p separated from the photosensitive drum 141 enters the fixing unit 147 via the transport mechanism, and the toner image is fixed by heat and pressure. Thus, an image is formed on the recording paper p. In this way, the recording paper p on which the image formation on the back surface and the front surface is completed is discharged from the paper discharge unit 15 to the outside of the apparatus.
[0012]
Meanwhile, there is an image forming apparatus having a function called automatic erasure outside a document. This automatic erasure outside the original is performed by reading the original on the platen glass 12 with the platen cover opened, and utilizing the fact that the signal value of the area outside the original is lower than that of the white area of the original. This is a function of identifying and obtaining an area outside the original by image processing, and automatically erasing the area outside the original to form an image only in the area of the original.
[0013]
In this case, a pre-scan is performed before the main scan, the area inside and outside the document is identified by the pre-scan to determine the size of the document, and the image of the document is read in the subsequent main scan.
[0014]
[Problems to be solved by the invention]
By the way, when the image reading unit 110 reads the original, if the scale plate 13 is read together with the original, the original size may be erroneously recognized in the automatic erasure outside the original. In other words, reading the scale plate 13 may erroneously recognize that a document larger than the actual document exists. One of the causes is that there is a slight difference in the mounting position and the mounting angle of the scale plate 13 due to an error at the time of manufacturing the apparatus.
[0015]
In order to solve such a problem of erroneous recognition, a normal image forming apparatus reads an area about 2 mm inward from an end of a document. As a result, a new problem arises in that the area of 2 mm around the document cannot be read at the portion in contact with the scale plate 13. If the margin of 2 mm is changed to 0.5 mm or the like in order to read the image in the document as much as possible, the above-described erroneous recognition of the document is likely to occur due to the problem of the mounting accuracy of the scale plate 13.
[0016]
The present invention has been made in view of the above-described problems, and is capable of correctly recognizing a document area at the time of automatic erasure outside a document with a minimum margin regardless of the mounting accuracy of the scale plate. It is intended to provide a forming apparatus.
[0017]
[Means for Solving the Problems]
The present invention that solves the above problems is configured as described in (1) to (5) below.
[0018]
(1) The invention according to claim 1 provides an image reading means having a scale plate at any position around a reading area when reading a document, and an image data obtained by reading by the image reading means. An image forming apparatus comprising: an image processing unit that performs image processing by using an image processing unit; and a control unit that controls a change in an image processing area in which image processing is performed on image data by the image processing unit. Read the maximum readable area including the scale plate in a state where no document is placed on the image reading means as a survey scan, and read the maximum range not including the scale plate in the read result of the survey scan. Wherein the rectangular area is determined as the image processing area.
[0019]
According to the present invention, when a scale plate is provided at any position around the reading area when reading a document, the maximum readable area including the scale plate without the document placed thereon is investigated and scanned. To determine the largest rectangular area not including the scale plate in the read result of the inspection scan as the image processing area.
[0020]
Here, the “image processing area” is a state in which at least the area of the scale plate is removed from the image data generated by the image reading unit, and it is determined that the image data is to be processed as the area of the image of the document. It is an area.
[0021]
As a result, the document area can be determined in a state that is distinguished from the scale plate by the survey scan, so that the document area can be correctly recognized at the time of automatic erasure outside the document with a minimum margin regardless of the mounting accuracy of the scale plate. And an image forming apparatus capable of performing the above. Note that this investigation scan may be performed at the time of shipment, installation, or at regular time intervals of the image forming apparatus.
[0022]
(2) The invention according to claim 2, wherein the control means determines the image processing area in accordance with the read result obtained by the inspection scan, regardless of the setting of the offset adjustment with respect to the image processing area. 2. The image forming apparatus according to claim 1, wherein a deviation adjustment is set for the image processing area determined by scanning.
[0023]
Here, the offset adjustment is an adjustment in which, when the sub-scanning direction (scanning direction) when scanning a document placed on the platen glass is set as the center axis, the center axis is shifted in a direction perpendicular to the axis. Means
[0024]
According to the present invention, even if the deviation adjustment is set for the image processing area, the investigation scan is executed with the deviation adjustment set canceled. Then, the image processing area is determined according to the reading result obtained by the survey scan. Then, a deviation adjustment setting is performed on the image processing area determined by the survey scan.
[0025]
This makes it possible to set an accurate scan area also in the shift direction, and in an actual scan, it is possible to set a scan area in accordance with the shift adjustment.
[0026]
(3) In the invention according to claim 3, the control means determines the image processing area according to a reading result obtained by a survey scan, irrespective of a setting of a tip timing adjustment value for the image processing area, 2. The image forming apparatus according to claim 1, wherein a setting of a front end timing adjustment is performed on the image processing area determined by a survey scan.
[0027]
Here, the leading end timing adjustment means an adjustment for shifting the start timing in the sub-scanning direction (scanning direction) when scanning a document placed on the platen glass.
[0028]
According to the present invention, even if the setting of the front end timing adjustment for the image processing area has been made, the investigation scan is executed in a state where the setting of the front end timing adjustment is canceled. Then, the image processing area is determined according to the reading result obtained by the survey scan. Then, the setting of the tip timing adjustment is performed on the image processing area determined by the survey scan.
[0029]
This makes it possible to set an accurate scan area also in the direction of tip timing adjustment, and to set a scan area in accordance with tip timing adjustment in an actual scan.
[0030]
(4) The invention according to claim 4, wherein the control means determines the image processing area in accordance with the read result obtained by the investigation scan, regardless of the setting of the offset adjustment or the tip timing adjustment for the image processing area. 2. The image forming apparatus according to claim 1, wherein the offset adjustment setting or the tip timing adjustment setting is performed on the image processing area determined by the investigation scan.
[0031]
According to the present invention, even if the offset adjustment or the tip timing adjustment is set for the image processing area, the investigation scan is executed in a state where the offset adjustment and the tip timing adjustment are cancelled. Then, the image processing area is determined according to the reading result obtained by the survey scan. Then, for the image processing area determined by the survey scan, the setting of the offset adjustment or the tip timing adjustment is performed.
[0032]
This makes it possible to set an accurate scan area for the direction of the offset adjustment and the tip timing adjustment, and to set the scan area according to the offset adjustment value and the tip timing adjustment in an actual scan. Can be set.
[0033]
(5) The image forming apparatus according to claim 5, wherein the image forming apparatus includes a platen cover that covers a reading area of the image reading unit, wherein the control unit performs an investigation scan with the platen cover closed. 5. The method according to claim 1, wherein, if performed, the signal value of the image read as the inspection scan is inverted, and a process for determining the image processing area is executed. 6. An image forming apparatus according to any one of claims 1 to 3.
[0034]
According to the present invention, when the inspection scan is performed with the platen cover closed, the signal value of the image read as the inspection scan is inverted, the position of the scale plate is detected, and the inspection scan is performed. The maximum rectangular area not including the scale plate in the read result is determined as the image processing area.
[0035]
As a result, not only when the platen cover is not closed, but also when the platen cover is closed, the document area can be determined in a state distinguished from the scale plate by the inspection scan. It is possible to provide an image forming apparatus capable of correctly recognizing a document area at the time of automatic erasure outside a document with a minimum margin regardless of the mounting accuracy.
[0036]
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 configuration diagram illustrating electrical components of the image forming apparatus according to the present embodiment. The external configuration of the image forming apparatus according to the present embodiment is the same as that shown in FIG. The mechanical configuration of the image forming apparatus according to the present embodiment is the same as that shown in FIG.
[0037]
In FIG. 1, reference numeral 101 denotes a control unit as a control unit for controlling each unit of the image forming apparatus, and is configured by a CPU and a control program. In this embodiment, a document is placed on the image reading unit. The maximum readable area including the scale plate in a state where it is not placed is read as a survey scan, and the maximum rectangular area not including the scale plate in the read result of the survey scan is determined as the image processing area. Control.
[0038]
When the image forming apparatus includes a plurality of control units and control units, a control unit that performs at least control related to reading corresponds to the control unit 101 of the present embodiment.
[0039]
Here, the "image processing area" is a state in which at least the area of the scale plate is removed from the image data generated by the image reading means, and should be processed as the area of the image of the document. , The area determined by the control unit 101.
[0040]
Reference numeral 110 denotes an image reading unit that optically reads an image of a document, and includes a CCD 111, a CCD driving unit 112, an optical system driving unit 113, and an AD converter 114.
[0041]
The CCD 111 is a line sensor having a plurality of light receiving units, and is provided with a light receiving unit of about 8000 elements in a direction perpendicular to the sheet of FIG. 6 when reading about A3 size. Note that the light receiving element array direction of the CCD 111 is the main scanning direction in reading.
[0042]
Reference numeral 112 denotes a CCD driving unit which generates a driving pulse or the like for driving the CCD 111 and supplies it to the CCD 111. An optical system driving unit 113 drives an optical system that moves during reading, and drives a light source 114a, mirrors 114b, 114c, 114d, and an imaging optical system 114e at a predetermined speed in accordance with reading. Note that the moving direction of the optical system by the optical system driving unit is the sub-scanning direction for reading.
[0043]
An A / D converter 114 converts an image signal output from the CCD 111 into a digital signal. The digital signal output from the A / D converter 114 is supplied to a page memory 131 described later.
[0044]
The image reading unit 110 reads the image surface of the document from the lower part of the platen glass 12 as shown in FIG. 6, but can read the image including the scale plate shown in FIG. It is configured as follows.
[0045]
An image processing unit 130 performs various image processing on image data obtained by reading, and includes a page memory 131 and a memory controller 132, and converts a digital signal from the image reading unit 110 into an image. Image processing for storing as image data for formation is executed.
[0046]
The page memory 131 is storage means for storing image data for image formation, and has a capacity capable of storing image data of a scale plate included in a reading result at the time of a survey scan. It is assumed that
[0047]
The memory controller 132 performs control to identify the scale plate included in the reading result of the inspection scan and to store the maximum rectangular area not including the scale plate in the page memory 131 as image processing of a normal scan.
[0048]
Reference numeral 140 denotes a print engine for forming an image, which can form an image by various methods such as an ink jet method and an electrophotographic method. FIG. 6 illustrates the print engine 140 of the electrophotographic system.
[0049]
Hereinafter, the operation of the image forming apparatus according to the present embodiment will be described with reference to the flowchart of FIG. In the image forming apparatus according to the present embodiment, in addition to the normal scan (pre-scan for reading the original size and the like before main scan, main scan for reading the image of the original), the image forming apparatus is shipped with It is characterized by a new "investigation scan" that is executed at the time of installation, at the time of occurrence of trouble, or at regular intervals.
[0050]
In this “investigation scan”, in a state where no original is placed on the platen glass 12 of the image reading unit 110, the maximum readable area including the scale plate is read as an investigation scan, and the inspection scan is read. The operation of determining the largest rectangular area not including the scale plate in the result as the image processing area is performed. Further, since this “investigation scan” is not necessary during normal operation, the control unit 101 may be configured to execute it when a special key input or the like is performed from the operation display unit 120.
[0051]
[1] Survey scan:
When a special key input or the like is performed from the operation display unit 120 at the time of factory shipment of the image forming apparatus, installation of a place of use, occurrence of a reading error, elapse of a certain use time, periodic inspection, or the like (S1 in FIG. 2). The control unit 101 executes an investigation scan described below.
[0052]
In this inspection scan, in a state where no original is placed on the platen glass 12 of the image reading unit 110, a readable maximum area including the scale plate 13 is read based on an instruction from the control unit 101 (see FIG. 2S2).
[0053]
Then, the memory controller 132 binarizes the image data (luminance data) of the read image data in order to distinguish the region of the scale plate 13 from the region of the platen glass 12 (S3 in FIG. 2). For example, the luminance data of each pixel of 8 bits (0 to 255) is set to “1” in the area of the scale plate 13 and “0” in the area of the platen glass 12 using a predetermined threshold value. Perform binarization so that
[0054]
In this case, when the platen cover 11 is in the open state, image data having a brightness corresponding to the color or density of the scale plate 13 is obtained in a portion where the scale plate 13 is present. In the portion, image data close to the black level is obtained without the presence of reflected light, and the presence of the scale plate 13 is preferable because it is clear.
[0055]
When the platen cover 11 is closed, the image data is inverted and the binary value is used by utilizing the fact that the platen cover 11 is white and the scale plate 13 is a color having a density other than white. If the binarized data is inverted or the binarized data is inverted, the same binarized data as when the platen cover 11 is open can be obtained.
[0056]
Then, the control unit 101 stores the binary data obtained as described above in the page memory 131 via the memory controller 132 (S4 in FIG. 2).
FIG. 3 shows an example of the binary data “0” and “1” stored in the page memory 131. It should be noted that although more data actually exists, the data is shown here in a reduced state for the sake of explanation.
[0057]
In FIG. 3, the portion of the binarized data “1” is a pixel in the area where the reflected light from the scale plate 13 is detected, and the portion of the binarized data “0” reflects the reflected light for the platen glass 12. This is a pixel in an area that could not be detected.
[0058]
FIG. 3 shows an example in which the scale plate 13 is mounted in a state where the main scanning direction and the sub-scanning direction are slightly deviated, and a diagonal broken line in the drawing substantially indicates an end position of the scale plate 13. ing.
[0059]
FIG. 3 exemplifies a case in which a document of A3 size (297 mm × 410 mm) and a document of a size called 11 × 17 (279.4 mm × 431.8 mm) can be read. The main scanning direction is configured to be able to read 297 mm, which is an A3-size width, and the sub-scanning direction is to be able to read 431.8 mm, which is 11 × 17 in size.
[0060]
In this state, the control unit 101 determines a maximum rectangular area not including the scale plate as image processing (S5 in FIG. 2). In the example shown in FIG. 3, a portion surrounded by a two-dot chain line is a maximum rectangular area not including the scale plate.
[0061]
Then, the control unit 101 stores the start address (Start (x1, y1)) and the end address (End (x2, y2)) of the rectangular area determined in this way (S6 in FIG. 2). At this time, the data may be stored in a register (not shown) or a nonvolatile memory.
[0062]
In addition to the start address (Start (x1, y1)) and end address (End (x2, y2)) corresponding to the maximum readable original size, as shown in FIG. It is also desirable to determine (Start (x3, y3)) and the end address (End (x4, y4)). In this case, in the case of a small original size, the start address has a different value depending on the inclination of the scale plate 13.
[0063]
When performing the above-described investigation scan, even if the offset adjustment or the tip timing adjustment is set, the investigation scan is executed in a state where the offset adjustment and the tip timing adjustment settings are canceled.
[0064]
Here, the offset adjustment is an adjustment in which, when the sub-scanning direction (scanning direction) when scanning a document placed on the platen glass is set as the center axis, the center axis is shifted in a direction perpendicular to the axis. Means Further, the leading end timing adjustment means an adjustment for shifting the start timing in the sub-scanning direction (scanning direction) when scanning a document placed on the platen glass.
[0065]
When the above-described investigation scan operation is completed, or when there is no specific key input after the power is turned on, the control unit 101 operates in the normal scan mode.
[0066]
[2] Normal scan:
When performing automatic erasure outside the original in the normal scan mode, the above-described rectangular area (image processing area) determined separately from the scale plate 13 by the above inspection scan is used.
[0067]
Here, the automatic erasure outside the original means that the original on the platen glass 12 is read with the platen cover opened, and that the signal value of the area outside the original is lower than that of the white area of the original. This is a function of identifying and obtaining an area and an area outside the original by image processing, and automatically deleting the area outside the original to form an image only in the area of the original. In this case, a pre-scan is performed before the main scan, and the area of the inside and outside of the document is identified by the pre-scan to obtain the document size.
[0068]
In this embodiment, the start address (Start (x1, y1)) and the end address (End (x2, y2)) obtained by the inspection scan are read, and a rectangular area surrounded by the start address and the end address is read. Is used as an “image processing area” at the time of prescan.
[0069]
Since the image processing area is determined not to be affected by the scale plate as described above, the back side of the scale plate 13 may be mistaken for the original when detecting the original size from the image data obtained by the prescan. Will not be recognized. In addition, the minimum amount of erasing of the original abutting against the scale plate 13 can be achieved.
[0070]
That is, according to the image forming apparatus of the present embodiment, it is possible to correctly recognize the original area at the time of automatic erasure outside the original with a minimum margin regardless of the mounting accuracy of the scale plate.
[0071]
In addition, when performing the deviation adjustment and the front end timing adjustment, desired values are added by adding the above-described start address (Start (x1, y1)) and end address (End (x2, y2)). Adjustment can be performed, and the effect of the above-described embodiment can be obtained also in automatic erasure outside a document.
[0072]
<Other embodiments>
The present embodiment can be applied to an image reading apparatus without the print engine 140.
[0073]
【The invention's effect】
As described in detail above, according to the present invention, an image forming apparatus capable of correctly recognizing a document area at the time of automatic erasure outside a document with a minimum margin regardless of the mounting accuracy of the scale plate. realizable.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an electrical configuration of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation state of the embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a data storage state of a page memory according to the embodiment.
FIG. 4 is an explanatory diagram showing a data storage state of a page memory in the embodiment.
FIG. 5 is a perspective view illustrating an external configuration of the image forming apparatus.
FIG. 6 is a perspective view illustrating a cross-sectional configuration of the image forming apparatus.
[Explanation of symbols]
110 image reading unit 120 operation display unit 130 image processing unit 140 print engine

Claims (5)

Image reading means having a scale plate at any position around the reading area when reading the original,
Image processing means for performing image processing on image data obtained by reading by the image reading means,
A control unit that controls a change in an image processing area that is a range in which image processing is performed on image data by the image processing unit
An image forming apparatus comprising:
The control unit causes a maximum readable area including the scale plate to be read as a survey scan in a state where a document is not placed on the image reading unit as a survey scan, and includes a scale plate in a read result of the survey scan. Determine the largest rectangular area as the image processing area,
An image forming apparatus comprising: The control means determines the image processing area according to the reading result obtained by the investigation scan, regardless of the setting of the deviation adjustment with respect to the image processing area, and determines the image processing area determined by the investigation scan. To set the offset adjustment,
The image forming apparatus according to claim 1, wherein: The control means determines the image processing area according to the reading result obtained by the investigation scan, regardless of the setting of the tip timing adjustment value for the image processing area, and determines the image processing area determined by the investigation scan. Set the tip timing adjustment for
The image forming apparatus according to claim 1, wherein: The control means determines the image processing area according to the reading result obtained by the investigation scan, regardless of the setting of the offset adjustment or the tip timing adjustment with respect to the image processing area, and the image determined by the investigation scan Set the offset adjustment or the tip timing adjustment for the processing area.
The image forming apparatus according to claim 1, wherein: An image forming apparatus including a platen cover that covers a reading area of the image reading unit,
When the inspection scan is performed in a state where the platen cover is closed, the control unit sets a signal value of an image read as the inspection scan in an inverted state to determine the image processing area. Run,
The image forming apparatus according to claim 1, wherein:

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