JP2010283741A - Image reading apparatus, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of performing appropriate reading corresponding to characteristics of an image without complicating and large-scaling the apparatus configuration, and to provide an image forming apparatus including the image reading apparatus. <P>SOLUTION: An image reading apparatus includes a light source 24a for irradiating a document P with illumination light, and a CCD sensor 28 for receiving light from the document P, obtained by irradiating the document P with the illumination light to obtain image data. The intensity and the irradiation time of the illumination light, with which the document is irradiated, are controlled, or the intensity of the illumination light, with which the document P is irradiated, and the time for the CCD sensor 28 to receive the light from the document P are controlled, and an image formed on the document P is read. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus and an image forming apparatus.

  An image reading apparatus is an apparatus for reading an image formed on a recording medium such as a document as image data, and is generally called a scanner. In addition to those sold as a single unit, this image forming apparatus may be provided in an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine. The basic reading principle is the same for both the image reading apparatus sold as a single unit and the image reading apparatus provided in the image forming apparatus. That is, the illumination light from the light source is irradiated onto the recording medium, and the light receiving element receives the reflected light or scattered light from the document while changing the relative positional relationship between the illumination light and the recording medium in the sub-scanning direction. Thus, the image formed on the recording medium is read as image data.

  Patent Document 1 below discloses an image reading method and apparatus capable of obtaining stable and high-quality image information with low power consumption while obtaining a sufficient amount of light for reading a document image with a simplified circuit configuration. Has been. Specifically, in a reduction system image reading apparatus that forms an image of reflected light obtained by irradiating an original with an LED with a lens and reads an image using a CCD sensor, residual heat control and heat retention control are performed on the LED. By providing a custom IC to be used, power consumption can be reduced.

Japanese Patent Laid-Open No. 11-98328

  By the way, as described above, the image reading apparatus irradiates the recording medium with illumination light, and changes the relative positional relationship between the illumination light and the recording medium in the sub-scanning direction while changing the relative positional relationship between the illumination light and the recording medium. Reading as data. For this reason, the image data for one line obtained by scanning in the main scanning direction orthogonal to the sub scanning direction is different from the image data obtained in a state where the recording medium is stationary with respect to the illumination light, in the sub scanning direction. The image data is averaged over the width of one line.

  When the image formed on the recording medium is an image such as a photograph in which the color boundary changes gently, the obtained image data is averaged over the width of one line in the sub-scanning direction. However, there is no particular problem. However, when an image formed on a recording medium is an image in which the color boundary changes sharply (steeply) such as characters, there is a problem that sharpness is lost and reproducibility is lowered. It was. In addition, since the illumination light from the light source is irradiated onto the recording medium with a width of one line or more in the sub-scanning direction, reflected light from a portion adjacent to the portion to be read is also received. There was also a problem that sharpness was lost.

  Conventionally, the sharpness has been compensated for this problem by performing image processing such as edge enhancement on the read image data. However, when such image processing is performed, other adverse effects such as loss of gradation are caused. In order to eliminate this adverse effect, a circuit and arithmetic processing for performing other image processing are newly required, and there is a problem that the image reading apparatus is complicated and enlarged.

  The present invention has been made in view of the above circumstances, and an image reading apparatus capable of performing appropriate reading according to the characteristics of an image without complicating and increasing the size of the apparatus, and the image reading An object of the present invention is to provide an image forming apparatus including the apparatus.

In order to solve the above problems, an image reading apparatus according to the present invention is an image reading apparatus that reads an image formed on a recording medium as image data, a light source unit that irradiates the recording medium with illumination light, and the recording medium. A light receiving unit that receives the light from the recording medium obtained by irradiating the illumination light and obtains the image data, the intensity of the illumination light at the time of reading an image formed on the recording medium, and the illumination light And a control unit that controls either of the irradiation time of light and the light reception time of light from the recording medium.
In the image reading apparatus of the present invention, the light source unit includes a plurality of LED elements.
Further, in the image reading apparatus of the present invention, the control unit increases the intensity of the illumination light when the irradiation time of the illumination light and the light reception time of the light from the recording medium are shortened, When either one of the illumination light irradiation time and the light receiving time from the recording medium is lengthened, control is performed to reduce the intensity of the illumination light.
The image reading apparatus of the present invention scans the recording medium in a main scanning direction intersecting the sub-scanning direction while changing a relative position between the recording medium and the light source unit in the sub-scanning direction. It is characterized by reading an image formed on a medium.
The image reading apparatus of the present invention is characterized in that the light receiving unit includes a plurality of light receiving elements arranged in a line so as to be able to read an image of the recording medium scanned in the main scanning direction. Yes.
The image reading apparatus according to the present invention is characterized in that the control unit performs the control in units of a period of scanning the recording medium in the main scanning direction.
The image reading apparatus of the present invention further includes a setting unit that sets a reading mode of an image formed on the recording medium, and the control unit is configured to change the reading mode set by the setting unit according to the reading mode. It is characterized by performing control.
An image forming apparatus according to the present invention is an image forming apparatus that forms an image on a recording medium, and includes any one of the image reading apparatuses described above that reads an image formed on the recording medium.

  According to the present invention, controlling the intensity and irradiation time of the illumination light irradiated to the recording medium, or controlling the intensity of the illumination light irradiated to the recording medium and the light receiving time of the light from the recording medium, Since the image formed on the recording medium is read, there is an effect that appropriate reading according to the characteristics of the image can be performed without complicating and increasing the scale of the apparatus configuration.

1 is a front view showing an external configuration of an image forming apparatus according to an embodiment of the present invention. 2 is a front perspective view showing an internal configuration of the image reading unit 1. FIG. 2 is a block diagram illustrating an internal configuration of a multifunction machine A. FIG. 5 is a flowchart showing the operation of the multifunction machine 1 when reading a document P. It is a figure for demonstrating the reading operation | movement at the time of normal reading mode. It is a figure for demonstrating the reading operation | movement at the time of character reading mode. It is a figure for demonstrating the reading operation | movement at the time of photograph reading mode.

  Hereinafter, an image reading apparatus and an image forming apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, a multi-function machine, which is a type of image forming apparatus, will be described as an example. FIG. 1 is a front view showing an external configuration of an image forming apparatus according to an embodiment of the present invention. The multi-function peripheral A as an image forming apparatus according to the present embodiment has a copy function, a print function, and a facsimile transmission / reception function, and copies a document, prints out various data created by using a computer, and the like. Facsimile transmission / reception is possible.

  As shown in FIG. 1, an MFP A includes an image reading unit 1 (image reading device) that reads an image of a document P (recording medium), a main body unit 2 that performs image formation on printing paper, and various information display and users. The operation display part 3 (setting means) which receives the operation instruction is provided. The image reading unit 1 includes an ADF (Auto Document Feeder) 10 (conveying unit) and a flat bed reading unit 20.

  The ADF 10 automatically and sequentially feeds a plurality of documents P set on the document placement tray 11 one by one, and is automatically stored in the platen cover 12, the document placement tray 11, and the platen cover 12. It consists of a paper feed mechanism (not shown). Note that the automatic paper feed mechanism in the platen cover 12 includes a pickup roller, a registration roller, a platen roller, and a paper discharge roller.

  The platen cover 12 is connected to the flat bed reading unit 20 by a hinge structure so that the platen cover 12 can be opened and closed with respect to the flat bed reading unit 20. The platen cover 12 has a role as a document pressing cover when a document P is set on the flat bed reading unit 20 for reading and a role as a housing for accommodating an automatic paper feeding mechanism. The platen cover 12 shown in FIG. 1 shows a closed state.

  The document placing tray 11 is a tray for setting a document P to be read. When the document P is set on the document placing tray 11, the document is transported by the automatic paper feeding mechanism housed in the platen cover 12, and the document image is read by the flat bed reading unit 20 during the transportation. When a plurality of originals P are set on the original placing tray 11, the originals P on the original placing tray 11 are sequentially conveyed and the original images are sequentially read by the flat bed reading unit 20.

  FIG. 2 is a front perspective view showing the internal configuration of the image reading unit 1. As shown in FIG. 2, the flat bed reading unit 20 forming a part of the image reading unit 1 includes a platen glass 21, a white reference plate 22, a document size instruction plate 23, a full rate carriage 24, a half rate carriage 25, and a carriage moving rail. 26, a condenser lens 27, a CCD (Charge Coupled Device) sensor 28 (light receiving unit), and a reading unit housing 29, a document set on the platen glass 21, or a document automatically fed by the ADF 10 Read.

  The platen glass 21 is a glass plate on which originals to be read are set one by one on the upper surface. The white reference plate 22 is a white plate serving as a basis for white reference data for shading correction. The document size instruction plate 23 indicates a document setting position when the user sets documents of various sizes on the platen glass 21. The full-rate carriage 24 is configured to be movable on the carriage moving rail 26 below the platen glass 21, and reciprocates along the platen glass 21 in the left-right direction (scanning direction) of the drawing sheet.

  The full-rate carriage 24 includes a light source 24a (light source unit) that emits illumination light obliquely upward, and a first mirror 24b that reflects reflected light of the illumination light toward a half-rate carriage 25 described later. Here, in this embodiment, a plurality of white LEDs (Light Emitting Diodes) are provided as the light source 24a. White LEDs have the advantage that they can be lit and extinguished in a very short time and consume less power than conventional cold cathode tubes and the like.

  Currently, various types of white LEDs have been proposed. In this embodiment, any type of white LED can be used. For example, light emitted from an LED that emits blue light is applied to a phosphor material to obtain yellow light, and white light is produced by a mixture of blue and yellow. From an LED that emits near ultraviolet light Either a system that mixes colors by applying emitted light to a phosphor material, or a system that provides LEDs that emit red, green, and blue light and emits them simultaneously to mix colors can be used. .

  Similar to the full-rate carriage 24, the half-rate carriage 25 is configured to be movable on a carriage moving rail 26, and reciprocates along the platen glass 21 in the horizontal direction (scanning direction) of the drawing sheet. The half-rate carriage 25 has a second mirror 25 a that reflects light from the first mirror 24 b provided on the full-rate carriage 24 downward, and the light reflected by the second mirror 25 a to the condenser lens 27. And a third mirror 25b that reflects toward the screen. Here, the ratio of the moving amount of the full rate carriage 24 and the moving amount of the half rate carriage 25 is controlled to be 1: 0.5. Thereby, the optical path length of the illumination light until reaching the condenser lens 27 is constant.

  The condensing lens 27 condenses the light reflected by the third mirror 25 b provided on the half-rate carriage 25 on the light receiving surface of the CCD sensor 28. The CCD sensor 28 includes a plurality of light receiving elements arranged in a line (line shape) so as to be able to read an image of a document P scanned in the main scanning direction described below, and a CCD driving unit (not shown). The analog signal corresponding to the image of the document is generated by photoelectrically converting the light collected on the light receiving surface by a plurality of light receiving elements. The analog signal generated by the CCD sensor 28 is output to the main body 2.

  The image reading unit 1 described above scans the document P in the main scanning direction intersecting the sub-scanning direction while changing the relative position of the document P and the light source 24a in the sub-scanning direction, and the image formed on the document P is scanned. read. Specifically, the image of the document set on the platen glass 21 is read by moving the full rate carriage 24 and the half rate carriage 25 along the carriage moving rail 26 in the sub-scanning direction. In contrast, an image of a document automatically fed by the ADF 10 is read by causing the full-rate carriage 24 and the half-rate carriage 25 to wait at a predetermined document reading position, and the ADF 10 transports the document along the sub-scanning direction.

  FIG. 3 is a block diagram showing the internal configuration of the multifunction device A. As shown in FIG. As shown in FIG. 3, the main unit 2 of the multi-function peripheral A includes a CPU (Central Processing Unit) 31 (control unit), a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, a paper transport unit 34, and a carriage drive. A circuit 35, an AFE (analog front end) 36, a light source drive circuit 37, an image data storage unit 38, an image forming unit 39, and a communication I / F unit 40 are provided.

  The CPU 31 refers to an operation instruction input from the operation display unit 3 or a communication I / F unit 40 while referring to various detection signals output from various sensor groups (not shown) based on a control program stored in the ROM 32. The operation of the main unit 2 is controlled in accordance with various instructions input from a client computer (not shown) via the computer. For example, image data reading control by the image reading unit 1 or printing control and transmission control of various image data such as document image data, print image data, and facsimile image data stored in the image data storage unit 38 is performed. .

  Here, the CPU 31 controls the intensity of the illumination light emitted from the light source 24a and the illumination on the document P according to the reading mode set by the operation display unit 3 when the image reading unit 1 controls the reading of the image data. Control with the irradiation time of light (hereinafter referred to as first control) is performed. Alternatively, when the image reading unit 1 controls the reading of the image data, the intensity of the illumination light emitted from the light source 24a and the illumination light for the document P are irradiated according to the reading mode set in the operation display unit 3. Then, control with the light receiving time of light obtained from the document P (hereinafter referred to as second control) is performed. This is an image in which the color boundary changes sharply (steeply), such as characters, even if the image formed on the document P is an image in which the color boundary changes gently, such as a photograph. This is because proper reading is performed according to the characteristics of the image. Details of the above control will be described later.

  The ROM 32 is a non-volatile memory that stores a control program executed by the CPU 31 and other data. The RAM 33 is a volatile memory used as a working area as a temporary storage destination of data when the CPU 31 executes a control program and performs various operations. The paper transport unit 34 includes a transport roller, a motor for driving the transport roller, and the like. The paper transport unit 34 transports printing paper stored in the paper tray to the image forming unit 39 and performs image forming processing in the image forming unit 39. The printed printing paper is conveyed to the paper discharge tray.

  The carriage drive circuit 35 generates a carriage drive signal for moving the full-rate carriage 24 and the half-rate carriage 25 of the flat bed reading unit 20 along the scanning direction under the control of the CPU 31 and outputs the carriage driving signal to the image reading unit 1. To do. Although not shown in FIG. 3, a circuit for driving the ADF 10 under the control of the CPU 31 is also provided. The AFE 36 includes an amplifier and an A / D converter. The AFE 36 converts an analog signal output from the CCD sensor 28 (see FIG. 2) into a digital signal (image data) and outputs the digital signal to the CPU 31. The image data input to the CPU 31 is stored in the image data storage unit 38.

  Under the control of the CPU 31, the light source driving circuit 37 supplies current to the light source 24 a provided in the image reading unit 1 to turn on the light source 24 a, or stops supplying current to the light source 24 a and turns off the light source 24 a. Let The light source drive circuit 37 changes the intensity of illumination light emitted from the light source 24a by changing the amount of current supplied to the light source 24a by, for example, PWM (Pulse Width Modulation) control. Although not shown in FIG. 3, a CCD drive unit that drives the CCD sensor 28 under the control of the CPU 31 is also provided.

  The image data storage unit 38 includes a memory such as a flash memory. Under the control of the CPU 31, the document image data, the print image data received by the communication I / F unit 40 from a client computer (not shown), and the communication Facsimile image data received from the public network (not shown) by the I / F unit 40 is stored. A magnetic storage device such as a hard disk may be provided instead of the memory.

  The image forming unit 39 performs image forming processing using document image data, print image data, or facsimile image data stored in the image data storage unit 38 under the control of the CPU 31. Specifically, the image forming image corresponding to the various image data is transferred onto the printing paper conveyed from the paper conveying unit 34 using toner, and the fixing process of the image forming image is performed by the fixing roller. The communication I / F unit 40 is connected to a client computer (not shown) or a public network (not shown), and transmits / receives various signals to / from the client computer or the public network.

  The operation display unit 3 includes a touch panel 3 a and various operation keys. The operation display unit 3 outputs operation contents of the operation keys to the CPU 31 and displays various information on the touch panel 3 a under the control of the CPU 31. Examples of the various operation keys provided in the operation display unit 3 include a start key, a stop key, a power key, and a numeric keypad (numerical value input key). The touch panel 3a is configured by a liquid crystal display, and the brightness of the screen is adjusted by a backlight.

  In the present embodiment, a setting button for setting a reading mode of an image formed on the document P is displayed on the touch panel 3a. When the user operates this setting button, the reading mode can be set. For example, a “photo original” setting button for setting a mode (hereinafter referred to as a photo reading mode) for reading an image in which the color boundary changes gently, such as a photograph, and a sharp color boundary, such as a character. A “character original” setting button for setting a mode for reading an image that changes to (hereinafter referred to as a character reading mode) is displayed.

  Next, the operation of the multifunction device 1 having the above configuration will be described. Here, an operation for reading an image formed on the original P using the image reading unit 1 will be described. FIG. 4 is a flowchart showing the operation of the multifunction device 1 when reading the document P. The flowchart shown in FIG. 4 is started when the user sets a document P on the document placing tray 11 or the platen glass 21 and operates the start key provided on the operation display unit 3 to instruct the start of reading. . Note that the reading mode of the original P can be set by operating the “photo original” setting button or the “character original” setting button displayed on the touch panel 3a before operating the start key.

  When the process shown in FIG. 4 is started, the CPU 31 first determines whether or not the user has set a reading mode (step S11). If the user has not operated both the “photo original” setting button and the “character original” setting button before operating the start key provided on the operation display unit 3, the determination result in step S11 is “NO”. . Then, the CPU 31 sets the intensity and irradiation time of the illumination light applied to the original P to predetermined specified values, and the image formed on the original P in the normal reading mode (hereinafter referred to as normal reading mode). Is read (step S12).

  FIG. 5 is a diagram for explaining a reading operation in the normal reading mode. In the following description, T is a scanning cycle in the main scanning direction (time for obtaining image data for one line). As shown in FIG. 5 (a), in the normal reading mode, the light source 24a is turned off at the start portion and the end portion of the scanning cycle, and the light source 24a is turned on only at the central portion of the scanning period. As done. By such control, in the normal reading mode, the illumination light having the intensity Q1 determined by the above-mentioned specified value is irradiated on the document P only for a period of about 60 to 70% of the period T in the central portion of the scanning period.

  Here, as described above, the image formed on the original P is read by scanning the original P in the main scanning direction while changing the relative position of the original P and the light source 24a in the sub-scanning direction. Now, as shown in FIG. 5B, consider a case where an image of a line denoted by reference numeral L2 is read. In FIG. 5B, hatched rectangular areas AP <b> 1 to AP <b> 3 are openings (reading positions on the document P) of three light receiving elements among the plurality of light receiving elements provided in the CCD sensor 28. Is shown.

  As described above, the light source 24a is turned off at the start of the scanning cycle when reading of the line L2 is started, and the light source 24a is turned on in the middle of the scanning cycle. For this reason, reading of the image of the line L2 is started in a state in which about 1/4 of the rectangular areas AP1 to AP3 are included in the previous line L1, and the remaining about 3/4 are included in the line L2. In the central portion of the scanning period, the light source 24a is turned on, and the image of the line L2 is read in a state where all of the rectangular areas AP1 to AP3 are included in the line L2.

  Further, as described above, since the light source 24a is turned off before reaching the end of the scanning cycle, about 3/4 of the rectangular areas AP1 to AP3 are included in the line L2, and the remaining line L2 is read. Is finished in a state in which about 1/4 of is included in the next line L2. As described above, in the normal reading mode, the reflected light from the lines L1 and L3 adjacent to the line L2 is received, and the read image data is influenced by the reflected light.

  On the other hand, if the user operates either the “photo original” setting button or the “character original” setting button before operating the start key provided on the operation display unit 3, the determination result in step S11 is “YES”. become. Then, the CPU 31 determines whether or not the reading mode set by the user is the character reading mode (step S13). If the user operates the “character original” setting button before operating the start key provided on the operation display unit 3, the determination result in step S13 becomes “YES”, and the CPU 31 irradiates the original P. The illumination light intensity is increased and the illumination light irradiation time is set short, and the image formed on the document P is read in the character reading mode (step S14).

  FIG. 6 is a diagram for explaining a reading operation in the character reading mode. As shown in FIG. 6A, in the character reading mode, as in the normal reading mode, the light source 24a is turned off at the start portion and the end portion of the scanning cycle, and the light source 24a is turned on only at the center portion of the scanning period. Control is performed in units of scanning period T. However, in the character reading mode, the intensity of the illumination light is increased to Q2 than in the normal reading mode, and the irradiation time of the illumination light is shortened to about 30 to 40% of the period T. The intensity Q2 and the irradiation time of the illumination light are set so that the amount of light irradiated on the document P is equal to the amount of light irradiated on the document P in the normal reading mode.

  Here, in the character reading mode, since the illumination light irradiation time is shortened, the light source 24a is turned on later than the light source 24a in the normal reading mode, and the light source 24a is turned off in the normal reading mode. This is performed earlier than the turn-off of 24a. For this reason, in the character reading mode, as shown in FIG. 6B, reading of the image of the line L2 is started and ended in a state where most of the rectangular areas AP1 to AP3 are included in the line L2.

  Thus, in the character reading mode, there is almost no influence of the reflected light from the lines L1 and L3 adjacent to the line L2. Further, since the time for reading the image of the line L2 is shorter than that in the normal reading mode, the effect of averaging the image data in the sub-scanning direction is also reduced. As a result, there is no problem that the reproducibility is deteriorated because the sharpness of an image in which the color boundary changes sharply (steeply) like a character or the like is lost. In addition to this, the intensity of the illumination light is increased by the amount of shortening of the illumination light irradiation time, and the amount of light applied to the document P is equal (approximately equal) to the amount of light applied to the document P in the normal reading mode. Thus, there is no problem that the obtained image data becomes dark overall.

  On the other hand, if the user does not operate the “character document” setting button before operating the start key provided on the operation display unit 3, the determination result in step S13 is “NO”. Then, the CPU 31 determines whether or not the reading mode set by the user is the photo reading mode (step S15). If the user operates the “photo original” setting button before operating the start key provided on the operation display unit 3, the determination result in step S15 is “YES”, and the CPU 31 irradiates the original P. The intensity of the illuminating light is reduced and the irradiation time of the illuminating light is set longer, and the image formed on the original P is read in the photo reading mode (step S16).

  FIG. 7 is a diagram for explaining a reading operation in the photo reading mode. As shown in FIG. 7A, in the photo reading mode, as in the normal reading mode and the character reading mode, the light source 24a is turned off at the start portion and the end portion of the scanning cycle, and the light source 24a is only in the central portion of the scanning period. The control to turn on is performed with the scanning cycle T as a unit. However, in the photo reading mode, contrary to the case where the character reading mode is set, the intensity of the illumination light is lowered to Q3 and the irradiation time of the illumination light is increased to about 90% of the period T compared to the normal reading mode. ing. Even when the photo reading mode is set, the intensity Q3 and the irradiation time of the illumination light are set so that the amount of light irradiated on the document P is equal to the amount of light irradiated on the document P in the normal reading mode. .

  Here, since the illumination light irradiation time is longer in the photo reading mode, the light source 24a is turned on earlier than the light source 24a in the normal reading mode, and the light source 24a is turned off in the normal reading mode. It is performed later than the turn-off of 24a. For this reason, in the photo reading mode, as shown in FIG. 7B, reading of the image of the line L2 is started in a state where about half of the rectangular areas AP1 to AP3 are included in the line L1, and the rectangular areas AP1 to AP3 are read. The reading of the image of the line L2 is completed with about half of the line L3 being included.

  Thus, in the photo reading mode, it is greatly affected by the reflected light from the lines L1 and L3 adjacent to the line L2. In addition, since the time for reading the image of the line L2 is longer than that in the normal reading mode, the effect of averaging the image data in the sub-scanning direction is improved. Thereby, it is possible to read an image such as a photograph in which the color boundary changes gently, as compared with the normal reading mode. In addition, in this mode, the amount of light applied to the document P is equal (almost equal) to the amount of light applied to the document P in the normal reading mode, so that the obtained image data is darkened as a whole. Does not occur.

  As described above, in the present embodiment, when reading an image formed on the original P, the intensity and irradiation time of the illumination light applied to the original P are controlled, so that the apparatus configuration is complicated and large. Appropriate reading according to the characteristics of the image can be performed without increasing the scale. Specifically, images with sharply changing color boundaries such as letters can be read without loss of sharpness, and images with smoothly changing color boundaries such as photographs For, a good image with smoother color boundaries can be read.

  The image reading apparatus and the image forming apparatus according to an embodiment of the present invention have been described above. However, the present invention is not limited to the above-described embodiment, and can be freely changed within the scope of the present invention. For example, in the above-described embodiment, the example in which the light source 24a is controlled to control the intensity and irradiation time of the illumination light irradiated on the document P has been described. However, the light source 24a may be controlled to control the intensity of illumination light applied to the document P, and the CCD sensor 28 may be controlled to control the light reception time obtained from the document P.

  In the above-described embodiment, the user operates either a “photo original” setting button for reading an image such as a photograph displayed on the touch panel 3a or a “character original” setting button for reading an image such as a character. The example of setting the character reading mode or the photo reading mode has been described. However, a larger number of reading modes in which the intensity of illumination light and the irradiation time are more precisely defined may be prepared so that the user can select one of the reading modes.

  In the above embodiment, the image reading unit 1 provided in the multifunction peripheral A is described as an example of the image reading device. However, the present invention is also applied to an image reading device sold as a so-called scanner. be able to.

DESCRIPTION OF SYMBOLS 1 Image reading part 3 Operation display part 24a Light source 28 CCD sensor 31 CPU
A MFP P Original

Claims (8)

In an image reading apparatus that reads an image formed on a recording medium as image data,
A light source unit for irradiating the recording medium with illumination light;
A light receiving unit that receives the light from the recording medium obtained by irradiating the illumination light to the recording medium and obtains the image data;
A controller that controls the intensity of the illumination light at the time of reading an image formed on the recording medium and either the irradiation time of the illumination light or the light reception time of light from the recording medium. An image reading apparatus.   The image reading apparatus according to claim 1, wherein the light source unit includes a plurality of LED elements.   The control unit increases the intensity of the illumination light when the illumination light irradiation time or the light reception time from the recording medium is shortened, and the illumination light irradiation time and the recording medium are 3. The image reading apparatus according to claim 1, wherein control is performed to reduce the intensity of the illumination light when either one of the light receiving times of the light is extended. 4.   Scanning the recording medium in the main scanning direction intersecting the sub-scanning direction while reading the image formed on the recording medium while changing the relative position of the recording medium and the light source unit in the sub-scanning direction. The image reading apparatus according to any one of claims 1 to 3, wherein the image reading apparatus is characterized.   The image reading apparatus according to claim 4, wherein the light receiving unit includes a plurality of light receiving elements arranged in a line so that an image of the recording medium scanned in the main scanning direction can be read.   The image reading apparatus according to claim 4, wherein the control unit performs the control in units of a period of scanning the recording medium in the main scanning direction. Comprising setting means for setting a reading mode of an image formed on the recording medium,
The image reading apparatus according to claim 1, wherein the control unit performs the control according to a reading mode set by the setting unit. In an image forming apparatus for forming an image on a recording medium,
An image forming apparatus comprising the image reading device according to claim 1, wherein the image reading device reads an image formed on a recording medium.

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