JP6358131B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus and an image forming apparatus, and more particularly to a technique for controlling output of image data.

  In an image reading apparatus such as an image forming apparatus, image data of a document read by a document reading unit is transmitted to another information device via network communication, and is also stored in an external storage medium such as a USB (Universal Serial Bus) memory. It is possible. Here, a long document is read by the image forming apparatus, and image data of the long document is transmitted to another information device by network communication or stored in the external storage medium. However, if color information is included in the document, the amount of color image data read is excessive, and this imposes pressure on the storage capacity of the server as another information device and the USB memory as the external storage medium. . As a method for preventing such compression of the storage capacity, there is a method of compressing data. For example, Patent Document 1 below discloses a technique for compressing data in accordance with the storage capacity of the memory.

JP 2003-251869 A

  However, in the conventional data compression technique as described above, if the amount of data is excessive, the compression process and the expansion process are repeated many times in order to match the storage capacity of the memory. It may take time.

  The present invention has been made in view of the above-described problem, and reduces the compression of the storage capacity of the data storage destination without performing compression processing even if the amount of read image data is excessive. For the purpose.

An image reading apparatus according to one aspect of the present invention includes a document reading unit that reads an image from a document,
A storage unit for storing image data of the document read from the document reading unit;
A detection unit for detecting the length of the document in the main scanning direction and the length of the document in the sub-scanning direction ;
When the length of the document detected by the detection unit in the main scanning direction is equal to or greater than a predetermined value, a first threshold value that is twice or more the predetermined value is set, and It is determined whether the length in the sub-scanning direction of the document detected by the detection unit is equal to or greater than the first threshold, and the length in the main scanning direction of the document detected by the detection unit is determined in advance. A second threshold value that is larger than the first threshold value is set, and the length of the document detected by the detection unit in the sub-scanning direction is equal to or greater than the second threshold value. A determination unit for determining whether or not ,
An output unit for outputting the image data stored in the storage unit;
An image processing unit that performs processing for converting the image data stored in the storage unit into monochrome data;
The length in the main scanning direction of the document detected by the detection unit is equal to or greater than the predetermined value, and the length in the sub-scanning direction of the document detected by the detection unit by the determination unit. When it is determined that it is greater than or equal to the first threshold, or the length of the document detected in the main scanning direction detected by the detection unit is less than the predetermined value, and the detection unit detects the detection When it is determined that the length of the document detected in the sub-scanning direction is equal to or greater than the second threshold, the image processing unit converts the image data stored in the storage unit into monochrome data. so done, in which comprises a control unit for performing monochrome output process for outputting the image data converted into the monochrome data to the output unit.

  An image forming apparatus according to an aspect of the present invention includes an image forming unit that forms an image on a recording sheet, and the image reading apparatus.

  According to the present invention, when it is determined that the size of a document from which an image has been read is greater than or equal to a predetermined threshold value, the read image data is output in monochrome. For example, when the length of the document including color information is very long and is equal to or greater than the threshold value, the read image data is output in monochrome. For this reason, the color of the image indicated by the image data is reduced to two and the color information of the image is remarkably reduced, so that the data amount of the image data is greatly reduced. As a result, the amount of image data that has been read can be greatly reduced without performing image data compression processing, thereby reducing pressure on the storage capacity of the storage device that stores the image data. Is done.

1 is a schematic partial cross-sectional front view illustrating a structure of an image forming apparatus configured to include an image reading apparatus according to an embodiment of the present invention. 1 is a functional block diagram schematically showing a main internal configuration of an image forming apparatus configured to include an image reading apparatus according to an embodiment of the present invention. 5 is a flowchart illustrating an example of processing performed by a control unit in an image forming apparatus configured to include an image reading apparatus according to an embodiment of the present invention. (A) (B) is a figure showing an example of an operation screen. It is a figure which shows the example of the original document whose length is more than a threshold value. It is a figure which shows the example of the original document whose length is smaller than a threshold value. It is the figure which showed the other example of the operation screen.

  Embodiments of an image reading apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic partial cross-sectional front view showing a structure of an image forming apparatus configured to include an image reading apparatus according to an embodiment of the present invention.

  An image forming apparatus 1 configured to include an image reading apparatus according to an embodiment of the present invention is a multifunction machine having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function. . The image forming apparatus 1 includes an operation unit 47, a document feeding unit 6, and a document reading unit 5 in the apparatus main body 11.

  The operation unit 47 receives instructions such as an image forming operation execution instruction and a document reading operation execution instruction from the operator for various operations and processes that can be executed by the image forming apparatus 1, and displays operation guidance to the operator. The display unit 473 is provided. Further, the image forming apparatus 1 is provided with a USB mounting portion 21 (FIG. 2) for connecting a USB memory M.

  A case where a document reading operation is performed in the image forming apparatus 1 will be described. The document reading unit 5 optically reads an image of the document fed by the document feeding unit 6 or the document placed on the document placing glass 161, and generates image data. Image data generated by the document reading unit 5 is stored in a built-in HDD (Hard Disk Drive) or a computer connected to a network.

  The document reading unit 5 includes a reading mechanism 163 having a light irradiation unit, a CCD (Charge Coupled Device) sensor, and the like. The document reading unit 5 uses the light irradiation unit to irradiate a document, and then reflects the reflected light to the CCD. The image is read from the original by receiving light with the sensor. The depth direction with respect to the paper surface is the main scanning direction, and the left-right direction in FIG. 1 is the sub-scanning direction.

  The document feeding unit 6 includes a document table 7 on which a document is placed, and a document detection sensor 8 having an optical sensor or the like provided along a document feeding path (not shown). The document detection sensor 8 includes, for example, an optical sensor, and is provided at a position corresponding to the leading end portion of the document placed on the document table 7 in the transport direction, and can detect the leading end portion and the trailing end portion of the document in the document transport direction. It is said that. A document information detection unit 103, which will be described later, receives a document feed based on an interval between a timing at which a signal for detecting the leading edge of the document is received from the document detection sensor 8 and a timing at which a signal for detecting the trailing edge is received. A length L of the document conveyed by the feeding unit 6 in the conveyance direction (coincident with the sub-scanning direction) is detected. The document detection sensor 8 and the document information detection unit 103 are examples of the detection unit in the claims.

  Next, a case where an image forming operation is performed in the image forming apparatus 1 will be described. The image forming unit 12 is fed from the paper feeding unit 14 based on image data generated by the document reading operation, image data stored in the built-in HDD, image data received from a network-connected computer, and the like. A toner image is formed on a sheet P as a recording sheet.

  The image forming unit 12 includes an image forming unit 12M for magenta (M), an image forming unit 12C for cyan (C), an image forming unit 12Y for yellow (Y), and an image forming unit 12Bk for black (Bk). The image forming units 12M, 12C, 12Y, and 12Bk are respectively provided with drum-type photoreceptors 121M, 121C, 121Y, and 121Bk, and the photoreceptors 121M, 121C, 121Y, and 121Bk are counterclockwise in the drawing. It is designed to rotate around. The photoconductors 121M, 121C, 121Y, and 121Bk are examples of the photoconductors in the claims.

  The transfer unit 120 includes an intermediate transfer belt 125 on which the toner image is transferred, a driving roller 125A, a driven roller 125B, and a primary transfer roller 126.

  The intermediate transfer belt 125 is stretched between the driving roller 125A and the driven roller 125B, and is driven by the driving roller 125A in contact with the peripheral surfaces of the photoconductors 121M, 121C, 121Y, and 121Bk. Travel endlessly in synchronization with 121C, 121Y, and 121Bk.

  Next, a case where color printing is performed will be described. The periphery of the photoreceptors 121M, 121C, 121Y, and 121Bk is uniformly charged (charging process), and the surface of the charged photoreceptors 121M, 121C, 121Y, and 121Bk is irradiated with laser light based on image data. Thus, a latent image is formed (exposure process), the latent image is visualized with toner (development process), and the toner image formed by the visualization is formed on the intermediate transfer belt 125 by the primary transfer roller 126. It is designed to be transcribed.

  The toner images of the respective colors (magenta, cyan, yellow, and black) transferred onto the intermediate transfer belt 125 are superimposed on the intermediate transfer belt 125 with the transfer timing adjusted to form a color toner image.

  The secondary transfer roller 210 passes a color toner image formed on the surface of the intermediate transfer belt 125 from the paper feed unit 14 through the conveyance path 190 at a nip portion N between the intermediate transfer belt 125 and the driving roller 125A. This is transferred onto the conveyed paper P. The color printing has been described so far. In the case of monochrome printing, the magenta, cyan, and yellow photoconductors 121M, 121C, and 121Y are not used, and the black photoconductor 121Bk is used. Only will be used.

  The fixing unit 13 fixes the toner image on the paper P by thermocompression bonding, and the paper P on which the color image has been formed is discharged to the discharge tray 151.

  The paper feeding unit 14 includes a plurality of paper feeding cassettes and a pickup roller 145 for picking up recording paper stored in each paper feeding cassette, and is a recording paper having a size designated by an instruction from an operator or the like. The corresponding pickup roller 145 is rotationally driven so as to pick up the sheet, and the designated recording paper is conveyed toward the nip portion N.

  A case where double-sided printing is performed in the image forming apparatus 1 will be described. After the sheet P having an image formed on one surface by the image forming unit 12 is sandwiched between the discharge roller pair 159, the sheet P is switched back by the discharge roller pair 159 and sent to the reverse conveyance path 195, The paper P is transported again to the upstream area in the transport direction by the transport roller pair 19. Thus, an image can be formed on the other side of the paper P.

  FIG. 2 is a functional block diagram schematically showing the main internal configuration of the image forming apparatus 1. The image forming apparatus 1 includes a control unit 10, a document feeding unit 6, a document reading unit 5, an image forming unit 12, an image memory 32, an HDD 92, a fixing unit 13, a drive motor 70, an operation unit 47, a facsimile communication unit 71, a network. The interface 91 and the USB mounting unit 21 are included. Components similar to those of the image forming apparatus 1 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted here.

  As described above, the document reading unit 5 includes the reading mechanism 163 (FIG. 1) having a light irradiation unit and a CCD sensor, and the light irradiation unit is controlled under the control of the control unit 100 constituting the control unit 10. The image is read from the original by irradiating the original with the light and receiving the reflected light by the CCD sensor.

  When the document detection sensor 8 provided in the document feeding unit 6 starts feeding the document placed on the document table 7 (FIG. 1) into the image forming apparatus 1 under the control of the control unit 100. Start detecting the original.

  The image memory 32 is an area for temporarily storing image data of a document obtained by reading by the document reading unit 5 and temporarily storing data to be printed by the image forming unit 12. . The HDD 92 is a large-capacity storage device that stores image data and the like of a document read by the document reading unit 5. The image memory 32 is an example of a storage unit in the claims.

  The image processing unit 34 performs processing for converting color image data stored in the image memory 32 into a monochrome image.

  The driving motor 70 is a driving source that applies a rotational driving force to each rotating member of the image forming unit 12, the conveyance roller pair 19 and the like. The facsimile communication unit 71 includes an encoding / decoding unit, a modulation / demodulation unit, an NCU (Network Control Unit), and the like (not shown), and performs facsimile communication using a public telephone line network.

  The network interface 91 includes a communication module such as a LAN (Local Area Network) board, and the external device 20 such as a personal computer in a local area or the Internet via a LAN connected to the network interface 91 or the like. Various types of data are transmitted and received.

  The USB mounting unit 21 includes a USB terminal 21 a for mechanically and electrically connecting to a terminal of the USB memory M. The control unit 100 can exchange data with the USB memory M via the USB mounting unit 21.

  The control unit 10 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a dedicated hardware circuit. The control unit 10 includes a control unit 100 that controls overall operation of the image forming apparatus 1. Further, the control unit 10 includes a determination unit 101, a setting unit 102, and a document information detection unit 103.

  Based on the document length L detected by the document information detection unit 103 (an example of the document size in the claims), the determination unit 101 has a document length that is equal to or greater than a predetermined threshold. Determine whether or not. When the determination unit 101 determines that the length L of the document is equal to or greater than the threshold value, the control unit 100 stores the image stored in the image memory 32 in the network interface 91 or the USB mounting unit 231 serving as an output unit. Output data as monochrome data.

  The setting unit 102 sets the threshold value according to an instruction input by an operation of the operation unit 47 by the operator.

  The document information detection unit 103 receives a document feeding unit based on an interval between a timing at which a signal for detecting the leading edge of the document is received from the document detection sensor 8 and a timing at which a signal for detecting the trailing edge is received. 6 detects the length L of the document conveyed. The document information detection unit 103 is an example of a detection unit in the claims.

  The control unit 10 functions as a control unit 100, a determination unit 101, a setting unit 102, and a document information detection unit 103 by an operation according to an operation control program installed in the HDD 92. However, the control unit 100, the determination unit 101, the setting unit 102, and the document information detection unit 103 can be configured by hardware circuits, respectively, regardless of the operation according to the operation control program by the control unit 10. . The same applies to each embodiment unless otherwise specified.

  Next, an example of the operation performed by the control unit 100 in the image forming apparatus 1 including the image reading apparatus according to the embodiment of the present invention will be described based on the flowchart shown in FIG. Here, as an example, the USB memory M is connected to the USB terminal 21a, and the image data read from the document is written to the USB memory M in accordance with an instruction input by the operation of the operation unit 47 by the operator. I will explain.

  First, the control unit 100 determines whether or not a document is placed on the document table 7 based on a document detection signal output from the document detection sensor 8 (S1). If the control unit 100 determines that the document is placed on the document table 7 (YES in S1), the control unit 100 causes the document feeding unit 6 to start feeding the document into the image forming apparatus 1 (S2). The information detection unit 103 is operated by the document feeding unit 6 based on the interval between the timing at which the signal for detecting the leading edge of the document is received from the document detection sensor 8 and the timing at which the signal for detecting the trailing edge is received. Document length detection processing for detecting the length L of the conveyed document is started (S3). The control unit 100 causes the document reading unit 5 to start reading an image from the document (S4). Image data obtained by reading by the document reading unit 5 is stored in the image memory 32. Here, in the present embodiment, it is assumed that the reading by the document reading unit 5 is performed as color reading. The method for detecting the length L of the document fed from the document table 7 is not limited to this process. Note that the processing after S2 is not performed until the control unit 100 determines that the document is placed on the document table 7 (NO in S1).

  The method for determining whether or not a document is placed on the document table 7 is not particularly limited. For example, a sensor for detecting that a document has hit the back of the document table 7, a document table 7 or the like, and a method in which the control unit 100 makes a determination based on detection results from these sensors.

  Next, the determination unit 101 determines that information on the length L in the sub-scanning direction of the document sent from the document detection sensor 8 has been acquired (YES in S5), and is further transmitted from the document reading unit 5. When it is determined that the reading of the document by the document reading unit 5 is completed based on the incoming information (YES in S6), the document length L detected by the document information detecting unit 103 is a predetermined threshold T (for example, 700 mm). It is determined whether or not the above is true (S7). Note that either of the processes of S5 and S6 may be performed first.

  When determining unit 101 determines that the length L of the document is equal to or greater than a predetermined threshold T (YES in S7), control unit 100 causes image processing unit 34 to read the image read by document reading unit 5. Image processing for converting the color image data stored in the memory 32 into monochrome (for example, monochrome 2 gradation) data is performed (S8). The control unit 100 causes the converted monochrome image data to be output from the USB mounting unit 21 to the USB memory M (S9).

  If the document image can be read in either color or monochrome in S4, the control unit 100 determines whether the image data stored in the image memory 32 is color, for example, ACS. When the stored image data is color image data, the image processing unit 34 performs image processing for converting the image data to monochrome when it is determined by determination (Auto Color Selection: automatic color selection processing) or the like. You may make it let.

  On the other hand, when the determination unit 101 determines in S7 that the length L of the document is not equal to or greater than a predetermined threshold T (NO in S7), the control unit 100 reads the image memory by reading the document memory 5. The color image data stored in 32 is output as it is from the USB mounting unit 21 to the USB memory M without causing the image processing unit 34 to perform monochrome image conversion processing (S9).

According to this embodiment, as shown in FIG. 5, a color document DC1 having an elongated color image to the document transport direction (sub scanning direction) is read by the document reading section 5, above the color original DC1 When the length L is equal to or greater than the threshold value, the color image data obtained by reading the color document by the document reading unit 5 is converted into monochrome by the image processing unit 34 and stored in the USB memory M. On the other hand, as shown in FIG. 6, when the length L of the color document DC2 is smaller than the threshold value, the image data obtained by reading the color document by the document reading unit 5 is converted into monochrome by the image processing unit 34. The color image data is not converted and is stored in the USB memory M as it is.

As described above, in the above-described embodiment, when it is determined that the length L of the document from which the image has been read is equal to or greater than the predetermined threshold T, the read image data is output in monochrome. Thus, as shown in FIG. 6 of the image indicated by the image data, color reduced to two colors, the color information of the image is significantly reduced, the data quantity of the image data is greatly reduced. Accordingly, the amount of data of the read image data can be greatly reduced without performing compression processing of the image data, so that the storage capacity of the storage destination of the image data, in this case, the storage capacity of the USB memory M The pressure is reduced.

  Note that the threshold T may be set freely by the operator. For example, when an instruction to change the threshold value is input from the operator via the operation unit 47, the control unit 100 causes the display unit 473 to display the operation screen D1 as illustrated in FIG. When the numerical value used as the threshold value T is input by the touch panel function provided in the display unit 473 using the operation screen D1 by the operation of the operation unit 47, the setting unit 102 sets the input numerical value as the threshold value T. After the next time, the determination unit 101 makes the above determination using the set new threshold T.

  In addition, the operator can freely set whether or not to execute the monochrome output process of the image data (here, both the monochrome conversion process and the output process described above) performed under the control of the control unit 100. You may do it. For example, when an instruction to set whether or not to perform monochrome output is input from the operator via the operation unit 47, the control unit 100 displays an operation screen as illustrated in FIG. D2 is displayed on the display unit 473, and when an instruction to disable the monochrome output is input by the touch panel function provided in the display unit 473 using the operation screen D2 by the operation of the operator, Thereafter, in the flowchart shown in FIG. 3, after determining YES in S1, the processes in S3, S5, S7, and S8 are skipped, and the processes in S2, S4, S6, and S9 are performed. In other words, the monochrome conversion process and the output process of the image data are performed only when an execution instruction is given by the operator.

  Alternatively, when an instruction to set whether or not to perform monochrome output is input from the operator via the operation unit 47, the control unit 100 displays an operation screen D3 as illustrated in FIG. An operation screen D3 having a button image B1 for accepting an instruction to execute only a part of the color image data read by the document reading unit 5 and stored in the image memory 32 is displayed on the display unit 473. When the button image B1 is pressed by an operation by the operator, an instruction to perform the monochrome output only on a part of the color image data is input by the touch panel function provided in the display unit 473. Accordingly, the control unit 100 and the image processing unit 34, for example, color image data for only a part of the color image data, for example, half the number of read originals. Only, or, only the color image data of the second and subsequent read original, monochrome conversion processing and output processing may be carried out.

  In the above embodiment, a case has been described in which the determination unit 101 determines whether or not to output image data in monochrome based on the length L of the document. However, information on the length L of the document is described. In addition, the determination unit 101 may make the above determination in consideration of information on the length W (document width) in the main scanning direction of the document.

For example, the determination unit 101 sets two elements, the length W of the document in the main scanning direction as 250 mm and the length of the document in the sub-scanning direction as L700 mm as the threshold value T, and both the length W and the length L are set as the threshold value T. If exceeded, or, in the case where at least one of length W or length L exceeds the threshold value T, so as to determine the original length is the threshold T or more.

  Thereby, for example, when the length W of the document in the main scanning direction is 250 mm or more and relatively long, the determination unit 101 sets the threshold T to 700 mm and the length W of the document in the main scanning direction is less than 250 mm. In a relatively short case, finer processing may be performed, such as setting the threshold T to 800 mm longer than 700 mm.

  Further, the determination unit 101 calculates the area of the document based on the information on the length W in the main scanning direction of the document and the information on the length L in the sub-scanning direction of the document, and the area is determined by a predetermined threshold T. Whether or not this is the case may be determined, and in accordance with the determination result, the control unit 100 may perform the monochrome conversion process and the output process of the image data.

  As for the detection method by the document information detection unit 103 of the length W (document width) in the main scanning direction of the document, for example, a guide for paper width alignment provided on the document table 7 and moving according to the document width. And a detection method based on the number of pixels in the main scanning direction of the document obtained from the image data read by the document reading unit 5 can be employed. Similarly, the document information detection unit 103 detects the length L in the sub-scanning direction of the document based on the number of pixels in the sub-scanning direction of the document obtained from the image data read by the document reading unit 5. Is also possible.

  In the above-described embodiment, the case where image data read from a document is written to the USB memory M is described. For example, this can be applied to an external network connected to the image forming apparatus 1 using the network interface 91 as an output unit. The image data may be transmitted to the apparatus 20 (for example, a server), or the read image data may be replaced when the image forming unit 12 is printed as an output unit.

  When image data is transmitted to the external device 20 via the network interface 91, as in the case of writing to the USB memory M, it is possible to reduce pressure on the storage capacity of the data storage destination. , Toner consumption can be reduced.

  In the above embodiment, as an example of the process of converting an image to monochrome, the conversion process to monochrome two gradations is given. However, the present invention is not limited to this, and is a process of converting an image to gray scale. Also good. For example, if a primary color has 256 gradations and the image is a full-color image using all three primary colors, the maximum is about 1.7 million gradations (256 gradations to the third power). Since there are 256 gradations, the amount of data can be made very small. Note that the control unit 100 sets whether the image conversion to monochrome is image conversion to grayscale or monochrome gradation, according to an instruction input by the operation of the operation unit 47 by the operator. You may make it do.

  In the above-described embodiment, the determination unit 101 determines that the document length L and / or the length W (hereinafter simply referred to as the length L) detected by the document information detection unit 103 is equal to or greater than a predetermined threshold T. When it is determined that there is (YES in S7), the control unit 100 performs image processing for converting the color image data into monochrome data (S8). Instead, in S3, The document information detection unit 103 detects the number of documents to be read as described above and is fed by the document feeding unit 6, and the determination unit 101 detects the document detected by the document information detection unit 103. When it is determined that the number of images is equal to or greater than a predetermined threshold T2 (YES in S7), the control unit 100 may cause the image processing to convert the color image data into monochrome data. S8).

  Furthermore, in S3, the document information detection unit 103 detects both the length and the number of documents to be read and fed by the document feeding unit 6 as described above. When the control unit 100 determines that the document length detected by the document information detection unit 103 is equal to or greater than the threshold value T or the number of documents is equal to or greater than the threshold value T2 (YES in S7), You may make it perform the image process which converts the said color image data into monochrome data (S8).

  Alternatively, in S3, the document information detection unit 103 detects both the length and the number of documents to be read and fed by the document feeding unit 6 as described above. When it is determined that the length of the document detected by the document information detection unit 103 is equal to or greater than the threshold value T and the number of documents is equal to or greater than the threshold value T2 (YES in S7), the control unit 100 stores the color image data. Image processing for conversion to monochrome data may be performed (S8).

  Note that the configurations and processes shown in the above embodiments using FIGS. 1 to 7 are only one embodiment of the present invention, and the configurations and processes of the present invention are not limited thereto.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 100 Control part 101 Judgment part 102 Setting part 103 Original length detection part 21 USB mounting part 47 Operation part 473 Display part 5 Original reading part 6 Original feeding part 7 Original stand 8 Original detection sensor 34 Image processing part 32 Image memory 91 Network interface

Claims (4)

An original reading unit for reading an image from an original;
A storage unit for storing image data of the document read from the document reading unit;
A detection unit for detecting the length of the document in the main scanning direction and the length of the document in the sub-scanning direction ;
When the length of the document detected by the detection unit in the main scanning direction is equal to or greater than a predetermined value, a first threshold value that is twice or more the predetermined value is set, and It is determined whether the length in the sub-scanning direction of the document detected by the detection unit is equal to or greater than the first threshold, and the length in the main scanning direction of the document detected by the detection unit is determined in advance. A second threshold value that is larger than the first threshold value is set, and the length of the document detected by the detection unit in the sub-scanning direction is equal to or greater than the second threshold value. A determination unit for determining whether or not ,
An output unit for outputting the image data stored in the storage unit;
An image processing unit that performs processing for converting the image data stored in the storage unit into monochrome data;
The length in the main scanning direction of the document detected by the detection unit is equal to or greater than the predetermined value, and the length in the sub-scanning direction of the document detected by the detection unit by the determination unit. When it is determined that it is greater than or equal to the first threshold, or the length of the document detected in the main scanning direction detected by the detection unit is less than the predetermined value, and the detection unit detects the detection When it is determined that the length of the document detected in the sub-scanning direction is equal to or greater than the second threshold, the image processing unit converts the image data stored in the storage unit into monochrome data. And a control unit that performs monochrome output processing for causing the output unit to output the image data converted into the monochrome data. The image reading apparatus according to claim 1 , wherein the control unit determines whether or not to perform the monochrome output process in part or in whole according to an execution instruction from an operator. The detection unit detects the number of documents,
When the control unit determines that the part is to be subjected to the monochrome output process according to an execution instruction from an operator, the control unit converts the image data of the predetermined number of documents detected by the detection unit to monochrome. The image reading apparatus according to claim 2, wherein the image processing unit performs a process of converting into data. An image forming unit for forming an image on recording paper;
Image forming apparatus and an image reading apparatus according to any one of claims 1 to 3.

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