JP5647950B2 - Image reading apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to an image reading apparatus that performs double-sided reading of a document. The present invention also relates to an image forming apparatus provided with the image reading apparatus.

  In recent years, printing is sometimes performed on both sides of a sheet from the viewpoint of effective use of the sheet. The image reading apparatus is equipped with two image sensors so that the user's work such as turning over the document or switching back the document is not necessary. Some of them are read in parallel (hereinafter, such a double-sided original reading format is referred to as “double-sided simultaneous reading”). An example of such an image reading apparatus is described in Patent Document 1.

  Specifically, Patent Document 1 discloses a first reading unit (image sensor) that operates based on a predetermined operation clock, reads image information on one side of a document, and outputs an image signal. Second reading means (image sensor) that operates based on the operation clock, reads image information on the other side of the document and outputs an image signal, and document reading mode for reading one side or both sides of the document Selection means for selecting the clock, clock generation means for supplying an operation clock to the first reading means and the second reading means, and an operation clock supplied by the clock generation means in accordance with the document reading mode selected by the selection means And an image reading apparatus including a control means for changing the frequency of the image. Accordingly, an image reading apparatus capable of reading both sides is made small and inexpensive (see Patent Document 1: Claim 1, paragraph [0007], etc.).

Japanese Patent Laid-Open No. 9-46484

  Image reading apparatuses and image forming apparatuses equipped with image reading apparatuses are provided with semiconductor devices (for example, ASIC, FPGA, etc.) that perform various image processing on image data obtained by reading.

  As described above, some image reading apparatuses are provided with two image sensors and capable of simultaneous reading on both sides. In such an image reading apparatus having a double-sided simultaneous reading function, if only one semiconductor device is provided, an image obtained by reading one image sensor can be used to process image data without problems such as delay. It is necessary to have the ability to perform image processing on the data and image data obtained by reading the other image sensor in parallel. For this reason, a semiconductor device that operates at a high frequency and at a high speed is required so that the image processing is completed within a predetermined time.

  However, in a multifunction device or the like, the double-sided simultaneous reading function may be available only after purchasing an optional device (for example, a document conveying device equipped with an image sensor) that supports double-sided simultaneous reading. In view of this, an image reading apparatus may be equipped with one semiconductor device that processes image data from a surface reading image sensor as a standard. A semiconductor device that processes image data from the image sensor for reading the back surface may be separately attached in accordance with the addition of the optional device (for example, built in a document conveying device as an optional device). As a result, it is not necessary to provide a semiconductor device that is standardly mounted on the image reading apparatus with performance sufficient to support simultaneous double-sided reading, and the manufacturing cost of the image forming apparatus and the image reading apparatus with the standard configuration can be reduced. As described above, a semiconductor device that performs image processing may be provided in each of the two image sensors.

  On the other hand, for example, a semiconductor device of an image reading apparatus having a plurality of functions such as copying, scanning, and image data transmission may perform image processing on image data stored in a storage unit (for example, HDD). Depending on the execution timing of document reading, image processing of image data obtained by reading the document by the image sensor and image processing of image data stored in the storage unit may be performed in parallel (hereinafter, as described above). Such parallel processing of two types of image data is referred to as “parallel image processing”).

  Here, in order to perform parallel image processing regardless of the presence / absence of an optional device, an image that can be processed in parallel by a normally mounted semiconductor device (a semiconductor device for surface reading) in parallel. Provide processing performance (not required for backside semiconductor devices). Therefore, a standard-equipped semiconductor device that performs parallel image processing is required to have a capability of performing parallel image processing without delay. As described above, when a plurality of semiconductor devices are mounted on the image reading apparatus, the required performance differs between the front surface semiconductor device and the back surface semiconductor device. In this case, a semiconductor device for a surface that requires high image processing performance (processing speed) operates at a high frequency at a high speed.

  For this reason, conventionally, the semiconductor device for the front surface and the semiconductor device for the back surface have been separately developed so that neither the over-spec nor the performance is insufficient. However, there is a problem that the development cost of the two semiconductor devices is required, and the development cost of the semiconductor device is high.

  Alternatively, since the processing contents performed by the front surface semiconductor device and the back surface semiconductor device are the same, the same semiconductor device may be used (mounted) for the front surface semiconductor device and the back surface semiconductor device. However, conventionally, although it is not necessary to perform parallel image processing, the semiconductor device for the back surface is operated at the same operation speed (same frequency) as the semiconductor device for the front surface. Therefore, it can be said that the semiconductor device for the back surface is operated at a higher frequency than necessary. When the semiconductor device for the back surface is operated at a frequency higher than necessary, there is a problem that extra power is consumed due to heat generation or the like. Further, if the semiconductor device for the back surface is operated at a frequency higher than necessary, a heat sink or a cooling fan with a large air volume is required for heat countermeasures, which may increase the manufacturing cost of the image reading apparatus. As described above, since the semiconductor device for the back surface is operated at a frequency higher than necessary (the same frequency as the semiconductor device for the front surface), problems such as excessive power consumption and cooling of the image reading apparatus are required. There is a problem that the manufacturing cost becomes high.

  Here, although the invention described in Patent Document 1 has a plurality of image sensors, it is unclear whether or not it has a plurality of semiconductor devices that process image data. The image reading apparatus described in Patent Document 1 is a facsimile machine, and does not process image data stored in a storage unit and image data obtained by reading in parallel. Therefore, the invention described in Patent Document 1 cannot solve the problem of the development cost of the semiconductor device and the above-mentioned problem caused by operating the semiconductor device for the back surface at a frequency higher than necessary.

  In view of the above-described problems of the prior art, the present invention suppresses the development cost of a semiconductor device that performs image processing and is mounted on an image reading apparatus, and is caused by the operation of a backside semiconductor device at a frequency higher than necessary. It is an object to suppress excessive power consumption and manufacturing cost increase.

In order to achieve the above object, an image reading apparatus according to claim 1 includes a conveyance reading contact glass for reading a document passing through an upper surface, and a placement reading contact glass for reading a placed document. An image reading unit that reads the original and generates image data; and is provided above the image reading unit, conveys the original along the original conveyance path, and conveys the original toward the conveyance reading contact glass A document conveying unit that stores image data, and a storage unit that stores image data. The image reading unit includes a first reading unit that reads one side of the document, a first drive signal generation unit that generates a drive signal, It operates at which the first drive signal generation unit according to the frequency of the drive signal generated includes a first semiconductor device intends row image processing on the image data obtained by the original reading of the first reading portion, Previous Document conveying unit, a second reading unit for reading the other surface of the document, and a second drive signal generator for generating a drive signal, at a rate that the second drive signal generating section corresponding to the frequency of the drive signal generating A second semiconductor device that operates and performs image processing on image data obtained by reading a document by the second reading unit, the storage unit includes an HDD, and the HDD includes an image of the first semiconductor device. The processed image data and the image data processed by the second semiconductor device are stored, and the first semiconductor device performs image processing on the image data obtained by reading the original in the first reading unit. The second semiconductor device performs parallel image processing in which image processing of another image data stored in the HDD is performed in parallel in order to perform a print or transmission job. Without sense, the first semiconductor device and the second semiconductor device, specification, design is the same, the second driving signal generating unit, than the drive signals the first drive signal generation section generates A drive signal having a slow frequency is generated.

  According to this configuration, the first semiconductor device and the second semiconductor device are the same. Accordingly, the same semiconductor device (semiconductor device) is used for the semiconductor device for reading the front surface (first semiconductor device) and the semiconductor device for reading the back surface (second semiconductor device). Therefore, it is not necessary to separately develop the first semiconductor device and the second semiconductor device, and the development cost of the semiconductor device can be suppressed.

  The second drive signal generation unit generates a drive signal having a slower frequency than the drive signal generated by the first drive signal generation unit. Accordingly, the second semiconductor device that does not need to perform parallel image processing on the image data stored in the storage unit and the image data obtained by reading the original in the second reading unit has an operating frequency higher than that of the first semiconductor device. It can be kept low. Therefore, by reducing the operating frequency of the second semiconductor device, the consumption of extra power due to heat generation in the second semiconductor device can be suppressed, and the cost required for heat countermeasures (installation of a heat sink or installation of a cooling fan with a large air volume) can also be suppressed. It is done.

  According to a second aspect of the present invention, in the first aspect of the invention, the first semiconductor device and the second semiconductor device each include an image processing circuit, and the first drive signal generation unit has a predetermined frequency. Generating an image processing circuit drive signal for driving the image processing circuit of the first semiconductor device, and the second drive signal generating unit driving the image processing circuit of the second semiconductor device, An image processing circuit drive signal having a predetermined frequency and a slower frequency than the image processing circuit drive signal generated by the first drive signal generation unit is generated.

  According to this configuration, since the second drive signal generation unit drives the image processing circuit of the second semiconductor device, the image processing circuit drive signal generated by the first drive signal generation unit has a predetermined frequency. A drive signal for an image processing circuit having a slower frequency is generated. As a result, it is possible to suppress the consumption of extra power in the image processing circuit that constitutes a part of the second semiconductor device that performs image processing, and it is possible to suppress the cost required for heat countermeasures.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, each of the first semiconductor device and the second semiconductor device includes an internal bus, and the first drive signal generation unit is predetermined. Generating an internal bus drive signal for driving the internal bus of the first semiconductor device at a predetermined frequency, and the second drive signal generation unit drives the internal bus of the second semiconductor device in advance. An internal bus drive signal having a defined frequency and a frequency slower than the internal bus drive signal generated by the first drive signal generation unit is generated.

  According to this configuration, since the second drive signal generation unit drives the internal bus of the second semiconductor device, the second drive signal generation unit has a predetermined frequency and is higher than the internal bus drive signal generated by the first drive signal generation unit. A drive signal for an internal bus having a low frequency is generated. As a result, it is possible to suppress the consumption of extra power in an internal internal bus that constitutes a part of the second semiconductor device that performs image processing, and it is possible to suppress the cost required for heat countermeasures.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the first drive is connected to the first semiconductor device so as to be communicable, and the first semiconductor device performs image processing. A first image memory that operates at a speed corresponding to the frequency of the memory drive signal generated by the signal generation unit and the second semiconductor device are communicably connected, and are used when the second semiconductor device performs image processing. And a second image memory that operates at a speed corresponding to the frequency of the memory drive signal generated by the second drive signal generation unit, wherein the first drive signal generation unit drives the first image memory. A second drive signal generator for driving the second image memory at a predetermined frequency to drive the second image memory. It was decided to produce a slow frequency memory drive signals than generating memory drive signal to.

  According to this configuration, since the second drive signal generation unit drives the second image memory, the memory has a predetermined frequency and a slower frequency than the memory drive signal generated by the first drive signal generation unit. Drive signal is generated. As a result, when the second semiconductor device performs image processing, it is possible to suppress consumption of extra power in the second image memory that stores image data to be subjected to image processing and image data after image processing. The cost required for heat countermeasures for image memory can also be reduced.

  According to a fifth aspect of the present invention, in the first to fourth aspects of the invention, the drive signal generated by the second drive signal generation unit, the image processing circuit drive signal, the internal bus drive signal, and the memory A setting unit for setting any one or a plurality of frequencies of the drive signal for use is included.

  According to this configuration, the setting for setting one or more frequencies of the drive signal generated by the second drive signal generation unit, the drive signal for the image processing circuit, the drive signal for the internal bus, and the drive signal for the memory Part. As a result, the frequency of various drive signals in the second semiconductor device and the image memory related to the second semiconductor device is adjusted to a frequency that is sufficient for image processing and that suppresses the consumption of excess power and heat generation. Can do.

  According to a sixth aspect of the present invention, in the first to fifth aspects of the present invention, the apparatus further includes a document conveyance unit that conveys the document along the document conveyance path, and the first reading unit is a document in the middle of the document conveyance path. The second reading unit reads the back side of the document in the middle of the document transport path, and the first reading unit and the second reading unit simultaneously read one document. .

  According to this configuration, the first reading unit reads the front side of the document in the middle of the document conveyance path, and the second reading unit reads the back side of the document in the middle of the document conveyance path, and the first reading unit and the second reading unit Performs simultaneous reading of one original. Thereby, the document can be read simultaneously (in parallel) by the two reading units.

  According to a seventh aspect of the present invention, there is provided an image forming apparatus according to any one of the first to sixth aspects, image data obtained by performing image processing on the first semiconductor device and the second semiconductor device. And an image forming unit for forming an image.

  According to this configuration, it is not necessary to separately develop two semiconductor devices in the image reading apparatus, and the development cost of an image forming apparatus equipped with the image reading apparatus can be reduced. In addition, since excessive heat is consumed in the second semiconductor device, the generated heat is suppressed, so that it is possible to provide an image forming apparatus equipped with an image reading apparatus with lower power consumption and lower cost.

ADVANTAGE OF THE INVENTION According to this invention, the development cost of the semiconductor device which performs the image process mounted in an image reader can be held down. Further, it is possible to suppress excessive power consumption and an increase in manufacturing cost due to the overspec of the semiconductor device for the back surface.

FIG. 2 is a front sectional view schematically showing a configuration of the multifunction machine. 1 is a schematic cross-sectional view illustrating an example of an image reading apparatus. 2 is a block diagram illustrating an example of a hardware configuration of a multifunction peripheral. FIG. FIG. 5 is a block diagram for explaining an example of a document reading flow in the image reading apparatus. It is a block diagram for demonstrating an example of a structure of each semiconductor device. It is a block diagram which shows an example of each drive signal generation part.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

(Outline of image forming apparatus)
First, an outline of an electrophotographic multifunction machine 101 (corresponding to an image forming apparatus) including an image reading apparatus 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic front sectional view showing a schematic configuration of the multifunction machine 101.

  As shown in FIG. 1, the multifunction peripheral 101 according to the present embodiment has an image reading apparatus 100 disposed above. The image reading apparatus 100 irradiates light on the upper surface of the conveyance reading contact glass 11a or the placement reading contact glass 11b, and generates image data by the first image sensor 12 (corresponding to the first reading unit) based on the reflected light. The image reading unit 1 is provided, and is provided above the image reading unit 1, opens and closes in the vertical direction with respect to the image reading unit 1, conveys the document toward the conveyance reading contact glass 11 a, and receives a second image sensor 21 (second A document conveying unit 2 including a 2 reading unit) is provided. Details of the image reading apparatus 100 will be described later.

  Further, as indicated by a broken line in FIG. 1, an operation panel 102 is provided on the front side of the image reading unit 1. The operation panel 102 includes a liquid crystal display unit 102a that displays keys for setting the multifunction peripheral 101 and receives user input via a touch panel. The liquid crystal display unit 102a can display the state of the multifunction machine 101 such as an error such as a jam or out of paper. In addition, a numeric keypad 102b for inputting numbers such as the number of copies, a start key 102c for instructing copy execution, and the like are arranged on the operation panel 102.

  As shown in FIG. 1, the multifunction peripheral 101 according to the present embodiment includes a sheet feeding unit 3a, a conveyance path 3b, an image forming unit 4a, an intermediate transfer unit 4b, a fixing unit 4c, and the like inside the main body. The plurality of paper feed units 3a in the multifunction peripheral 101 main body are each of a size (for example, A type, B4 type A, B type paper, etc.), various types of paper (for example, copy paper, recycled paper, cardboard, OHP sheet). Etc.). Each paper feed unit 3a includes a paper feed roller 31 that is driven to rotate, and at the time of printing, one of the paper feed rollers 31 rotates to feed the paper one by one into the transport path 3b.

  The transport path 3b is a path for transporting paper within the apparatus. Then, on the conveyance path 3b, a guide plate for guiding the paper, a conveyance roller pair 32 that is rotationally driven during conveyance of the paper (in FIG. 1, a total of three from 32a, 32b, and 32c from the top) are conveyed. A registration roller pair 33 or the like is provided that waits for the sheet to be printed in front of the image forming unit 4a and feeds the sheet in accordance with the transfer timing of the formed toner image. In addition, a pair of discharge rollers 35 for discharging the sheet after completion of fixing to the discharge tray 34 is also provided.

  The image forming unit 4a includes a plurality of image forming units 40 (40Bk for black, 40Y for yellow, 40C for cyan, and 40M for magenta) and an exposure device 41. The exposure device 41 outputs laser light while turning it on and off based on the image data read by the image reading unit 1, and scans and exposes each photosensitive drum. The image forming unit 40 includes a photosensitive drum that is rotatably supported, and a charging device, a developing device, a cleaning device, and the like disposed around the photosensitive drum. Then, a toner image is formed on the peripheral surface of the photosensitive drum by each image forming unit 40 and the exposure device 41.

  The intermediate transfer unit 4b receives the primary transfer of the toner image from each image forming unit 40 and performs the secondary transfer on the sheet. The intermediate transfer unit 4b includes primary transfer rollers 42Bk to 42M, an intermediate transfer belt 43, a drive roller 44, a plurality of driven rollers 45a and 45b, a secondary transfer roller 46, a belt cleaning device 47, and the like. Each primary transfer roller 42 </ b> Bk to 42 </ b> M sandwiches the corresponding photosensitive drum and the endless intermediate transfer belt 43. A transfer voltage is applied to each of the primary transfer rollers 42 </ b> Bk to 42 </ b> M, and the toner image is transferred to the intermediate transfer belt 43.

  The intermediate transfer belt 43 is stretched around the drive roller 44, the primary transfer rollers 42Bk to 42M, and the like. The intermediate transfer belt 43 circulates by rotational driving of a driving roller 44 connected to a driving mechanism (not shown) such as a motor. The drive roller 44 and the secondary transfer roller 46 sandwich the intermediate transfer belt 43. The toner images (black, yellow, cyan, and magenta colors) formed by the image forming units 40 are sequentially transferred to the intermediate transfer belt 43 in a superimposed manner without deviation, and then applied with a predetermined voltage. The image is transferred onto the sheet by the secondary transfer roller 46.

  The fixing unit 4c fixes the toner image transferred to the paper. The fixing unit 4c mainly includes a heating roller 48 containing a heating element and a pressure roller 49 that is in pressure contact with the heating roller 48. When the paper passes through the nip between the heating roller 48 and the pressure roller 49, the toner is melted and heated, and the toner image is fixed on the paper. The sheet discharged from the fixing unit 4 c is sent to the discharge tray 34.

(Configuration of Image Reading Apparatus 100)
Next, an example of the image reading apparatus 100 according to the embodiment will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing an example of the image reading apparatus 100.

  As described above, the image reading apparatus 100 includes the document conveying unit 2 and the image reading unit 1. First, the document conveying unit 2 will be described. The document conveying section 2 automatically and continuously conveys the document to be read one by one to a reading position (a contact glass 11a for conveyance reading described later). The document transport unit 2 includes, in order from the upstream side in the document transport direction, a document tray 22, a document supply roller 23, a document transport path 24, a plurality of document transport roller pairs 25, a document discharge roller pair 26, a document discharge tray 27, and the like. The document conveying unit 2 is attached to the image reading unit 1 so as to be able to be opened and closed in the vertical direction with the back side of the sheet of FIG. 2 as a fulcrum, and functions as a cover for pressing each contact glass of the image reading unit 1 from above.

  A plurality of documents to be read are placed on the document tray 22 with the front side facing up. Then, the document supply roller 23 contacts the uppermost document among the documents placed on the document tray 22. For example, when an input to read a document, such as pressing the start key 102c, is input to the multi-function peripheral 101, the document supply roller 23 sends the document one by one to the document transport path 24.

  The fed document is guided to a plurality of document transport roller pairs 25 and guides, and passes through the upper surface of the transport reading contact glass 11 a provided on the upper surface of the image reading unit 1. During this passage, the image reading unit 1 performs reading. Then, the document that has been read is discharged from the document discharge roller pair 26 to the document discharge tray 27 (the document transport path is indicated by a two-dot chain line). Each of the rotating bodies (the document supply roller 23, the document transport roller pair 25, and the document discharge roller pair 26) rotates using the document transport motor 28 (see FIG. 4) as a drive source.

  The document transport unit 2 is provided with, for example, a second image sensor 21 that reads the back surface of the document to be transported on the upstream side in the document transport direction in the vicinity of the document discharge roller pair 26. The second image sensor 21 is a CIS (Contact Image Sensor) image sensor. Further, for example, the second image sensor 21 corresponds to reading in color, and includes line sensors of three colors R, G, and B in which a plurality of light receiving elements are arranged. The second image sensor 21 also includes a second light source 29 (for example, an LED or a fluorescent tube, see FIG. 4) that irradiates light on the back surface of the document, and a lens that guides the reflected light of the document.

  As the document is transported, the second image sensor 21 performs line-by-line reading in the main scanning direction (direction perpendicular to the document transport direction) on the back side of the document. The second image sensor 21 converts the reflected light into an analog electric signal corresponding to the image density. The line-by-line reading is continuously repeated in the sub-scanning direction (document conveying direction) to read the back side of one document.

  Next, the image reading unit 1 in the present embodiment will be described. As shown in FIGS. 1 and 2, the image reading unit 1 has a box-shaped housing. Then, on the left side of the upper surface of the image reading unit 1, a transparent plate-shaped conveyance reading contact glass 11 a extending in a direction perpendicular to the paper surface of FIG. 2 is arranged. Then, on the right side of the upper surface of the image reading unit 1, a transparent plate-like placement reading contact glass 11b is arranged extending in a direction perpendicular to the paper surface. When reading a document such as a book one by one, the document is placed with the document transport unit 2 lifted and the reading surface facing downward.

  As shown in FIG. 2, the first moving frame 131, the second moving frame 132, the wire 141, the winding drum 142, the lens 15, and the first light that irradiates the original in the housing of the image reading unit 1. A light source 16 (for example, an LED or a fluorescent tube) and light applied to the original are incident, and a first image sensor 12 for reading the original for each line and generating image data is disposed. The first image sensor 12 is composed of, for example, a CCD (Charge Coupled Device) in which photoelectric conversion elements are arranged in a line shape, and reads the surface of the document for each line based on the reflected light of the document.

  Reflected light emitted from the first light source 16 and reflected upon the original on the conveyance reading contact glass 11a or the original on the placement reading contact glass 11b is reflected by the first mirror 171, the second mirror 172, and the third mirror. It is guided to the lens 15 by reflection by 173. The lens 15 condenses the reflected light and enters the first image sensor 12. The first image sensor 12 includes, for example, three color line sensors of R, G, and B in which a plurality of light receiving elements are arranged. The first image sensor 12 converts the reflected light into an analog electrical signal corresponding to the image density. Reading of the original is performed in units of lines in the main scanning direction (direction perpendicular to the original conveying direction), and reading in units of lines is continuously repeated in the sub-scanning direction (original conveying direction). The surface is read.

  The first moving frame 131 supports the first light source 16 that emits light upward and the first mirror 171 below. The first light source 16 and each mirror have a shape extending in the direction perpendicular to the paper surface of FIG. The second moving frame 132 supports the second mirror 172 on the upper side and the third mirror 173 on the lower side. Further, the first moving frame 131 is disposed above the second moving frame 132. A plurality of wires 141 are attached to the first moving frame 131 and the second moving frame 132 (only one is shown in FIG. 2 for convenience). The other end of the wire 141 is connected to the winding drum 142, and the winding drum 142 rotates forward and backward using the winding motor 14 (see FIG. 4) as a drive source, and the first moving frame 131 and the second moving frame 132 are Move freely in the horizontal direction.

  Here, an example of the reading operation of the surface of the document using the first image sensor 12 will be described. First, in the case of front side reading or double-sided simultaneous reading of a document transported by the document transport unit 2, after the winding motor 14 is driven, the first moving frame 131 and the second moving frame 132 are transported and read contact glass 11a. Is fixed at a lower position (reading position). Then, the first light source 16 irradiates the passing document. Then, each pixel of the first image sensor 12 outputs an analog electrical signal corresponding to the reflected light.

  On the other hand, when reading a document placed on the placement reading contact glass 11b, the first moving frame 131 and the second moving frame 132 are moved from the home position to the right in FIG. The entire original is read and the original image is converted into an analog electrical signal.

(Hardware configuration of MFP 101)
Next, an example of the hardware configuration of the multifunction peripheral 101 according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram illustrating an example of a hardware configuration of the multifunction machine 101.

  The multi-function peripheral 101 is provided with a main control section 5 that performs overall control and performs image processing by control of each section in the multi-function peripheral 101 and communication control. The main control unit 5 is provided with a CPU 51 as a central processing unit. In addition, a storage unit 55 composed of a nonvolatile and volatile storage device such as a ROM 52 (Read Only Memory), a RAM 53 (Random Access Memory), a HDD 54 (Hard disk drive), or a flash ROM is provided in the main control unit 5 ( It may be outside the main controller 5).

  The storage unit 55 stores programs, data, and the like for controlling the multifunction machine 101. The main control unit 5 uses the programs and data stored in the storage unit 55 to control each unit and to perform printing and data transmission. The storage unit 55 can store and store image data based on reading by the image reading apparatus 100 and image data transmitted from the external computer 200 or the FAX apparatus 300 and received by the communication unit 57.

  Further, the main control unit 5 is provided with an image processing unit 56 that performs image processing on image data obtained by reading by the image reading apparatus 100 and image data stored in the storage unit 55. For example, the image processing unit 56 includes an ASIC, a memory, and the like, and performs various types of image processing for printing and transmitting image data to the outside, such as density conversion processing, enlargement / reduction processing, rotation processing, and data format conversion. Yes. Note that the image processing unit 56 can perform other image processing (for example, frame erasing processing) and the like, but a description thereof is omitted because it can perform known image processing.

  In addition, the multifunction machine 101 is provided with a communication unit 57 that transmits and receives image data to and from the external computer 200 and the FAX apparatus 300. The communication unit 57 receives image data to be printed and setting data for printing from the computer 200 and the FAX apparatus 300 (printer and FAX function). Further, the communication unit 57 can transmit image data based on document reading by the image reading apparatus 100 to the computer 200 or the FAX apparatus 300 (transmission function, FAX function). The main control unit 5 is communicably connected to the operation panel 102. Settings and copy execution instructions on the operation panel 102 are transmitted to the main control unit 5.

  The main control unit 5 is connected to an engine control unit 4d that controls printing by performing ON / OFF of a motor that rotates an image forming unit and various rotating bodies. The engine control unit 4d is not provided, and the main control unit 5 may perform printing control instead.

  The engine control unit 4d is connected to the paper feed unit 3a, the conveyance path 3b, the image forming unit 4a, the intermediate transfer unit 4b, and the fixing unit 4c. When printing, the main control unit 5 gives an instruction for print contents to the engine control unit 4d according to the setting on the operation panel 102. The engine control unit 4d performs operation control of each unit such as paper conveyance, toner image formation, and ON / OFF of various motors based on an instruction from the main control unit 5.

  The main control unit 5 is also connected to the image reading unit 1 and the document conveying unit 2. The main control unit 5 gives an operation instruction to the image reading unit 1 and the document conveying unit 2 when executing document reading for copying or image data transmission. As a result, the image reading unit 1 and the document conveying unit 2 perform document reading. The main control unit 5 receives, for example, image data of a document, and causes the engine control unit 4d to perform printing (copy) based on the image data, and causes the communication unit 57 to transmit image data (transmission). function).

(Flow of document reading by the image reading apparatus 100)
Next, an example of a document reading flow in the image reading apparatus 100 according to the embodiment will be described with reference to FIG. FIG. 4 is a block diagram for explaining an example of a document reading flow in the image reading apparatus 100.

  As described above, the image reading apparatus 100 according to the present embodiment includes the document conveying unit 2 and the image reading unit 1. Further, since the image processing of the image data stored in the storage unit 55 is performed, as shown in FIG. 4, the image reading apparatus 100 of the present embodiment also includes the main control unit 5 (storage unit 55). The image reading unit 1 is provided with a reading control unit 10 that controls the operation of the image reading unit 1. On the other hand, the document transport unit 2 is provided with a document transport control unit 20 that controls the operation of the document transport unit 2.

  First, the flow of document reading in the image reading unit 1 will be described. The reading control unit 10 is communicably connected to the main control unit 5 and the document conveyance control unit 20. Then, in response to an instruction and signal from the main control unit 5, operation control of members in the image reading unit 1 is performed.

  For example, the reading control unit 10 is a substrate including a CPU as a central processing unit, and a ROM and RAM as storage devices for storing control programs and data. When an instruction for reading a document is received from the main control unit 5, the reading control unit 10 drives the winding motor 14 to rotate the winding drum 142 to read the first moving frame 131 and the second moving frame 132. Move to the corresponding position.

  Further, the image reading unit 1 has a first light source 16, a first image sensor 12, a first AFE 18 (Analog Front End), a first semiconductor device 61, a first image memory 71, etc. Provided.

  When receiving a document reading (front surface reading) instruction from the main control unit 5, the image reading unit 1 turns on the first light source 16. Then, the first image sensor 12 reads the surface of the document. An analog signal output from each light receiving element (photoelectric conversion element) of the first image sensor 12 is input to the first AFE 18. The first AFE 18 is, for example, an analog signal amplifier, an AGC (Auto Gain Control) circuit, or an odd / even signal that is output from the first image sensor 12 and corrects a difference in characteristics between odd and even signals. It includes an EVEN correction circuit, an A / D conversion circuit that converts an analog signal adjusted by various correction and adjustment circuits into a digital signal, and the like.

  The image data converted into a digital signal by the first AFE 18 is input to the first semiconductor device 61. The first semiconductor device 61 is an integrated circuit dedicated to image processing, such as ASIC or FPGA. The first semiconductor device 61 includes, for example, various correction processes (γ correction process, etc.), color conversion processes (for example, conversion from RGB format to other formats such as CMYK), zoom processing such as enlargement and reduction, and encoding processing. (Compression, decompression, and data format conversion to, for example, JPEG format) are performed.

  Further, a first image memory 71 is provided as a storage area used by the first semiconductor device 61. For example, the first image memory 71 is a DRAM, and is a memory module such as DDR, DDR2, or DDR3. The first image memory 71 stores image data on which the first semiconductor device 61 is to perform image processing and image data on which the first semiconductor device 61 has performed image processing. Then, the image data subjected to the image processing by the first semiconductor device 61 is output from the first semiconductor device 61 or the first image memory 71 toward the main control unit 5. The image data is temporarily stored in, for example, the RAM 53 of the main control unit 5, and is used for printing or transmission after the image processing unit 56 on the main body side separately performs image processing, or the storage unit 55 (for example, , HDD 54).

  Next, document reading on the document conveying unit 2 side will be described. The document conveyance control unit 20 is connected to the main control unit 5 and the reading control unit 10 described above, and receives instructions and signals from the main control unit 5 and the reading control unit 10 to control the operation of members provided in the document conveyance unit 2. I do.

  The document conveyance control unit 20 is, for example, a substrate including a CPU as a central processing unit, a ROM and a RAM as storage devices for storing control programs and data. For example, when a document reading instruction is issued from the main control unit 5, the document transport motor 28 is driven to rotate the document supply roller 23, the document transport roller pair 25, and the like.

  When the operation panel 102 is instructed to perform double-side reading, the main control unit 5 instructs the document conveyance control unit 20 to read the back side of the document. The document transport unit 2 is provided with a second light source 29, a second image sensor 21, a second AFE 20a (Analog Front End), a second semiconductor device 62, a second image memory 72, and the like for reading the back side of the document.

  When receiving a back side reading instruction from the main control unit 5, the document conveyance control unit 20 turns on the second light source 29. Then, the second image sensor 21 reads the back side of the document passing therethrough. The second image sensor 21 outputs an analog signal of each light receiving element (photoelectric conversion element) and inputs it to the second AFE 20a. The second AFE 20a is, for example, an ODD / ODC that corrects a difference in characteristics between an odd-numbered signal and an even-numbered signal output from the second image sensor 21 or an analog signal amplifier, an AGC (Auto Gain Control) circuit, or the like. It includes an EVEN correction circuit, an A / D conversion circuit that converts an analog signal adjusted by various correction and adjustment circuits into a digital signal, and the like. The second AFE 20a performs the same processing as the first AFE 18, but the first image sensor 12 and the second image sensor 21 have different types of image sensors, and therefore the parameters in each processing are different.

  The image data converted into a digital signal by the second AFE 20 a is input to the second semiconductor device 62. The second semiconductor device 62 is, for example, an integrated circuit dedicated to image processing, such as ASIC or FPGA. In the present embodiment, the first semiconductor device 61 and the second semiconductor device 62 are the same device (the same specification and the same design).

  Therefore, the second semiconductor device 62 can perform the same image processing as the first semiconductor device 61. For example, the second semiconductor device 62 includes various correction processes (γ correction process, etc.), color conversion processes (for example, conversion from RGB format to other formats such as CMYK), zoom processing such as enlargement and reduction, and encoding processing. (Compression, decompression, and data format conversion to, for example, JPEG format) can be performed.

  A second image memory 72 is provided as a storage area used by the second semiconductor device 62. For example, the second image memory 72 is also a DRAM and is a memory module of DDR, DDR2, and DDR3. The second image memory 72 stores image data on which the first semiconductor device 61 is to perform image processing and image data on which the second semiconductor device 62 has performed image processing. Then, the image data after the image processing of the second semiconductor device 62 is completed is output from the second semiconductor device 62 and the second image memory 72 toward the main control unit 5. Then, for example, after the image data is temporarily stored in the RAM 53 of the main control unit 5, the image processing unit 56 separately performs image processing, and then is combined with the surface image data and used for printing and transmission. Or stored in the storage unit 55 (for example, the HDD 54).

  Here, the first semiconductor device 61 and the second semiconductor device 62 are the same device, but the first semiconductor device 61 performs image processing on the image data stored in the storage unit 55 (for example, the HDD 54). Specifically, the main control unit 5 supplies the image data in the storage unit 55 together with information indicating image processing to be performed to the first semiconductor device 61 via the first image memory 71 or directly.

  For example, the engine control unit 4d performs printing based on the image data stored in the storage unit 55. The communication unit 57 transmits the image data to the external computer 200 or the FAX apparatus 300 based on the image data stored in the storage unit 55. In order to make effective use of the first semiconductor device 61 when performing printing or transmission based on the image data stored in the storage unit 55, for example, the image processing unit 56 of the main control unit 5 generates printing data. For example, the first semiconductor device 61 can perform image processing. The first semiconductor device 61 performs image processing on the image data stored in the storage unit 55. The image data after the image processing performed by the first semiconductor device 61 is output to the main control unit 5 again.

  The first semiconductor device 61 can perform image processing on the image data stored in the storage unit 55 in parallel when performing image processing on the image data obtained by reading the original of the first image sensor 12. Yes (parallel image processing). For example, when the operation panel 102 is instructed to transmit image data (such as network transmission or FAX transmission) based on the image data stored in the storage unit 55 while scanning a document for copying, the first semiconductor The device 61 performs parallel image processing.

(Configuration of each semiconductor device)
Next, an example of the configuration of each semiconductor device of this embodiment will be described with reference to FIG. FIG. 5 is a block diagram for explaining an example of the configuration of each semiconductor device.

  As described above, the first semiconductor device 61 and the second semiconductor device 62 are the same device (the same design and the same specification).

  The first semiconductor device 61 includes, for example, a controller 631, a plurality of image processing circuits 641, an input I / F unit 651, a memory I / F unit 661, a main body side I / F unit 671, a first drive signal generation unit 81, and the like. And are communicably connected by an internal bus 681.

  Similarly, the second semiconductor device 62 includes, for example, a controller 632, a plurality of image processing circuits 642, an input I / F unit 652, a memory I / F unit 662, a main body side I / F unit 672, a second drive signal generation unit. 82 and the like, and are communicably connected by an internal bus 682.

  The controller 631 of the first semiconductor device 61 inputs / outputs image data to / from the first image memory 71 and the image based on an instruction of image processing to be performed from the main control unit 5, the reading control unit 10, or the document conveyance control unit 20. The operation of the first semiconductor device 61 is controlled, such as input of image data to the processing circuit 641 and output of processed image data to the main control unit 5.

  Similarly, the controller 632 of the second semiconductor device 62 inputs / outputs image data to / from the second image memory 72 based on image processing instructions to be executed from the main control unit 5, the reading control unit 10, and the document conveyance control unit 20. The control of the operation of the second semiconductor device 62 is performed such as input of image data to the image processing circuit 642 and output of processed image data to the main control unit 5.

  Each image processing circuit 641 in the first semiconductor device 61 is divided into a plurality of blocks according to the content of the image processing, such as various correction processing, color conversion processing, zoom processing, and encoding processing. Each image processing circuit 641 performs image processing on the image data.

  Similarly, the image processing circuit 642 in the second semiconductor device 62 is also provided by being divided into a plurality of blocks according to the contents of the image processing, such as various correction processing, color conversion processing, zoom processing, and encoding processing. Each image processing circuit 642 performs image processing on the image data.

  The input I / F unit 651 of the first semiconductor device 61 is an interface that receives input of image data processed by the first AFE 18. The memory I / F unit 661 of the first semiconductor device 61 is an interface for writing image data to the first image memory 71 and reading image data from the first image memory 71. The main body side I / F unit 671 of the first semiconductor device 61 receives an instruction (data) indicating the contents of image processing to be executed, receives image data stored in the storage unit 55 from the main control unit 5, and after processing. This is an interface for transmitting the image data to the main control unit 5.

  The input I / F unit 652 of the second semiconductor device 62 is an interface that receives input of image data processed by the second AFE 20a. The memory I / F unit 662 of the second semiconductor device 62 is an interface for writing image data to the second image memory 72 and reading image data from the second image memory 72. The main body side I / F unit 672 is an interface that transmits an instruction (data) indicating the contents of image processing to be executed and image data after processing to the main control unit 5.

  The first drive signal generation unit 81 of the first semiconductor device 61 generates a clock signal as a drive signal. The first drive signal generation unit 81 supplies drive signals to the controller 631, the plurality of image processing circuits 641, the input I / F unit 651, the memory I / F unit 661, the main body side I / F unit 671, and the internal bus 681. It is a circuit to do. For example, the first drive signal generation unit 81 includes a first PLL circuit 831 (Phase Locked Loop circuit). Details of the first drive signal generator 81 will be described later.

  The second drive signal generation unit 82 of the second semiconductor device 62 also generates a clock signal as a drive signal. The second drive signal generation unit 82 sends drive signals to the controller 632, the plurality of image processing circuits 642, the input I / F unit 652, the memory I / F unit 662, the main body side I / F unit 672, and the internal bus 682. It is a circuit to supply. For example, the second drive signal generation unit 82 includes a second PLL circuit 832 (Phase Locked Loop). Details of the second drive signal generator 82 will also be described later.

(Drive signal frequency)
Next, each drive signal generation unit of the present embodiment will be described with reference to FIG. FIG. 6 is a block diagram illustrating an example of each drive signal generation unit.

  The image reading apparatus 100 and the multifunction peripheral 101 according to the present embodiment include a first semiconductor device 61 that processes image data obtained by reading the surface of a document by the first image sensor 12 and a document by the second image sensor 21. Two semiconductor devices, the second semiconductor device 62 for processing image data obtained by reading the back surface, are provided. The first semiconductor device 61 and the second semiconductor device 62 are the same.

  The first semiconductor device 61 has an image processing performance sufficient to perform parallel image processing of image data stored in the storage unit 55 and image data obtained by reading the first image sensor 12 without delay. On the other hand, since the second semiconductor device 62 does not perform parallel image processing, the image processing speed as high as that of the first semiconductor device 61 is not required.

  Therefore, in the image reading apparatus 100 and the multifunction peripheral 101 of the present embodiment, the first semiconductor device 61 is operated at a frequency at which parallel image processing can be performed without problems such as delay. In other words, the first semiconductor device 61 can perform parallel image processing. On the other hand, the second semiconductor device 62 is operated at a lower frequency than the first semiconductor device 61. As a result, power loss due to operation at a high frequency and heat generation in the second semiconductor device 62 and the like are reduced. In addition, the reduction in the amount of heat generated eliminates the need for an additional heat sink and an expensive cooling fan with a high blowing capacity.

  As described above, the first semiconductor signal 61 is provided with the first drive signal generator 81, and the second semiconductor device 62 is provided with the second drive signal generator 82. For example, as shown in FIG. 6, the first drive signal generator 81 is provided with a first PLL circuit 831. In addition, since the first semiconductor device 61 and the second semiconductor device 62 are the same, the second drive signal generator 82 is similarly provided with the second PLL circuit 832.

  A first reference clock generation unit 93 that inputs the reference signal CLK01 to the first PLL circuit 831 is provided. The first reference clock generation unit 93 may be externally attached to the first semiconductor device 61 or may be incorporated therein. For example, the first PLL circuit 831 generates a drive signal CLK1 (clock signal) having a frequency that is an integral multiple (multiplication) of the reference signal CLK01 generated by the first reference clock generation unit 93.

  Further, a second reference clock generation unit 94 for inputting the reference signal CLK02 to the second PLL circuit 832 is provided. The second reference clock generation unit 94 may be externally attached to the second semiconductor device 62 or may be incorporated therein. For example, the second PLL circuit 832 generates a drive signal CLK2 (clock signal) having a frequency that is an integral multiple (multiplication) of the reference signal CLK02 generated by the second reference clock generation unit 94.

  The first drive signal generation unit 81 is provided with an image processing circuit drive signal generation unit 841. The image processing circuit drive signal generation unit 841 generates an image processing circuit drive signal CLK11 (clock signal) for each image processing circuit 641 in the first semiconductor device 61, and the image processing circuit 641 generates the image processing generated. A circuit drive signal CLK11 is supplied (for convenience, only one image processing circuit 641 is shown in FIG. 6). For example, the image processing circuit drive signal generation unit 841 is a frequency divider (for example, a counter or a multiplication circuit), and generates the image processing circuit drive signal CLK11 having a predetermined frequency in terms of specifications. Each image processing circuit 641 in the first semiconductor device 61 operates at a speed corresponding to the frequency of the image processing circuit drive signal CLK11.

  On the other hand, since the first semiconductor device 61 and the second semiconductor device 62 are the same device (specification and design), the second drive signal generation unit 82 is also provided with an image processing circuit drive signal generation unit 842. The image processing circuit drive signal generation unit 842 in the second drive signal generation unit 82 is the same as that of the first drive signal generation unit 81. Specifically, the image processing circuit drive signal generation unit 842 generates a drive signal CLK21 (clock signal) for each image processing circuit 642 in the second semiconductor device 62 and generates the image processing generated in each image processing circuit 642. The circuit drive signal CLK21 is supplied (for convenience, only one image processing circuit 642 is shown in FIG. 6). Each image processing circuit 642 in the second semiconductor device 62 operates at a speed corresponding to the frequency of the image processing circuit drive signal CLK21.

  The first drive signal generation unit 81 is provided with an internal bus drive signal generation unit 851. The internal bus drive signal generator 851 generates an internal bus drive signal CLK12 (clock signal) to be supplied to the internal bus 681 in the first semiconductor device 61. For example, the internal bus drive signal generation unit 851 is a frequency divider (for example, a counter or a multiplier circuit), and generates the internal bus drive signal CLK12 for the internal bus 681 of the first semiconductor device 61. For example, the internal bus 681 and various I / F units in the first semiconductor device 61 operate at a speed corresponding to the frequency of the internal bus drive signal CLK12.

  On the other hand, since the first semiconductor device 61 and the second semiconductor device 62 are the same device (specification, design), the second bus signal generator 82 is also provided with an internal bus drive signal generator 852. The internal bus drive signal generator 852 in the second drive signal generator 82 is the same as that of the first drive signal generator 81. Specifically, the internal bus drive signal generation unit 852 generates an internal bus drive signal CLK22 (clock signal) to be supplied to the internal bus 682 in the second semiconductor device 62. For example, the internal bus 682 and various I / F units in the second semiconductor device 62 operate at a speed corresponding to the frequency of the internal bus drive signal CLK22.

  The first drive signal generator 81 is provided with an image memory drive signal generator 861. The image memory drive signal generator 861 generates a memory drive signal CLK 13 (clock signal) to be supplied to the first image memory 71. For example, the image memory drive signal generator 861 is a frequency divider (for example, a counter or a multiplier circuit). The first image memory 71 operates at a speed corresponding to the frequency of the memory drive signal CLK13.

  On the other hand, since the first semiconductor device 61 and the second semiconductor device 62 are the same device (specification, design), the second drive signal generation unit 82 is also provided with an image memory drive signal generation unit 862. The image memory drive signal generator 862 in the second drive signal generator 82 is the same as that of the first drive signal generator 81. Specifically, the image memory drive signal generation unit 862 generates a memory drive signal CLK23 (clock signal) to be supplied to the second image memory 72. The second image memory 72 operates at a speed corresponding to the frequency of the memory drive signal CLK23.

  Although an example in which a part for generating each drive signal is provided for each image processing circuit, internal bus, and image memory, the drive signals CLK1 and CLK2 generated by the first PLL circuit 831 and the second PLL circuit 832 are used as they are. If it can be used, the drive signal may be supplied to each image processing circuit, internal bus, and image memory as it is.

  Here, as described above, the first semiconductor device 61 is operated at a frequency that allows parallel image processing without problems. On the other hand, the second semiconductor device 62 is operated at a lower frequency than the first semiconductor device 61. Therefore, the frequency of various drive signals for operating the first semiconductor device 61 is different from the frequency of various drive signals for operating the second semiconductor device 62. Therefore, a first frequency setting unit 91 for setting the frequency of the drive signal CLK1 generated by the first drive signal generation unit 81 can be provided. Similarly, a second frequency setting unit 92 (corresponding to a setting unit) for setting the frequency of the drive signal CLK2 generated by the second drive signal generation unit 82 can be provided.

  The first frequency setting unit 91 is provided, for example, in a form externally attached to the first semiconductor device 61 (first drive signal generation unit 81). For example, the frequency of the drive signal CLK1 to be generated by the first drive signal generation unit 81 (first PLL circuit 831) is set by an external pin of the first frequency setting unit 91. Frequency setting information corresponding to the pin setting in the first frequency setting unit 91 is input to the first drive signal generation unit 81. The first PLL circuit 831 generates the drive signal CLK1 at a frequency based on the frequency setting information set by the first frequency setting unit 91.

  Similarly, the second frequency setting unit 92 is provided in a form externally attached to the second semiconductor device 62 (second drive signal generation unit 82), for example. For example, the frequency of the drive signal CLK2 to be generated by the second drive signal generation unit 82 (second PLL circuit 832) is set by an external pin of the second frequency setting unit 92. Frequency setting information corresponding to the pin setting in the second frequency setting unit 92 is input to the second drive signal generation unit 82. The second PLL circuit 832 generates the drive signal CLK2 at a frequency based on the frequency setting information set by the second frequency setting unit 92.

  Alternatively, the drive to be generated by the first drive signal generation unit 81 (first PLL circuit 831) and the second drive signal generation unit 82 (second PLL circuit 832) in the storage unit 55 of the main control unit 5 (corresponding to the setting unit). Information (frequency setting information) indicating the frequency of the signal (clock signal) is stored in advance. Then, frequency setting information that defines the frequency of the drive signal to be generated from the main control unit 5 to the first drive signal generation unit 81 and the second drive signal generation unit 82 via the main body side I / F units 671 and 672. May be given. In other words, the frequency of the drive signal generated by the first drive signal generation unit 81 and the second drive signal generation unit 82 can be set by software.

  Thus, the first semiconductor device 61 and the second semiconductor device 62 have the same configuration, but the frequency of the drive signal generated by the first drive signal generation unit 81 and the second drive signal generation unit 82 can be set. Can be varied according to the setting.

  Here, the frequency setting information for the first drive signal generation unit 81 is determined such that the first drive signal generation unit 81 generates the drive signal CLK1 at a frequency that allows the first semiconductor device 61 to perform parallel image processing without any problem. It is done. On the other hand, the second semiconductor device 62 is operated at a lower frequency than the first semiconductor device 61. Therefore, the frequency setting information for the second drive signal generation unit 82 generates the drive signal CLK2 having a frequency lower than that of the drive signal CLK1 generated by the first drive signal generation unit 81 by the second drive signal generation unit 82. It is determined to do.

  The frequency of the drive signal CLK2 generated by the second drive signal generation unit 82 is set to a frequency that allows the second semiconductor device 62 to process the image data of the document read by the second image sensor 21 without delay. . Thus, the frequency of the drive signal CLK2 generated by the second drive signal generation unit 82 (second PLL circuit 832) is lower than the frequency of the drive signal CLK1 generated by the first drive signal generation unit 81.

  Since the first semiconductor device 61 and the second semiconductor device 62 are the same, the frequency of the image processing circuit drive signal CLK21 supplied to each image processing circuit 642 of the second semiconductor device 62 is the same as that of the first semiconductor device 61. The image processing circuit drive signal CLK11 supplied to each of the image processing circuits 641 has a lower frequency. The frequency of the internal bus drive signal CLK22 supplied to the internal bus 682 of the second semiconductor device 62 is lower than the frequency of the internal bus drive signal CLK12 supplied to the internal bus 681 of the first semiconductor device 61. The frequency of the memory drive signal CLK23 supplied to the second image memory 72 is lower than that of the memory drive signal CLK13 supplied to the second image memory 72. Accordingly, the operating frequency of the second semiconductor device 62 is suppressed to be lower than the operating frequency of the first semiconductor device 61.

  As described above, the operating frequency, which is one of the factors that determine the operating speed (image processing performance) of the second semiconductor device 62, is intentionally lower than that of the first semiconductor device 61. In other words, the frequency of the drive signal (clock signal) that determines the operation of the second semiconductor device 62 is statically (fixedly) changed in a direction to be lower than the frequency of the first semiconductor device 61.

As described above, the image reading apparatus 100 according to the present embodiment includes the storage unit 55 (such as the HDD 54) that stores image data, the first reading unit (first image sensor 12) that reads one side of the document, and the drive. The first drive signal generation unit 81 that generates the signal CLK1 and the image data obtained by reading the document of the first reading unit that operates at a speed corresponding to the frequency of the drive signal CLK1 generated by the first drive signal generation unit 81 A first semiconductor device 61 capable of performing image processing on the image and image processing of image data stored in the storage unit 55 in parallel, and a second reading unit (second image sensor 21 for reading the other side of the document). ), A second drive signal generation unit 82 for generating the drive signal CLK2, and a speed corresponding to the frequency of the drive signal CLK2 generated by the second drive signal generation unit 82, and the original of the second reading unit A second semiconductor device 62 that performs image processing on the image data obtained by the up saw, wherein the first semiconductor device 61 and the second semiconductor device 62 is the same as, the second drive signal generator 82, A drive signal CLK2 having a slower frequency than the drive signal CLK1 generated by the first drive signal generation unit 81 is generated.

  As a result, the same semiconductor device (semiconductor device) is used for the semiconductor device for reading the front surface (first semiconductor device 61) and the semiconductor device for reading the back surface (second semiconductor device 62). Therefore, it is not necessary to develop the first semiconductor device 61 and the second semiconductor device 62 separately, and the development cost of the semiconductor device can be suppressed. In addition, the second semiconductor device does not require parallel processing of the image data stored in the storage unit 55 (HDD 54 or the like) and the image data obtained by the original reading of the second reading unit (second image sensor 21). 62 has an operating frequency lower than that of the first semiconductor device 61. Therefore, by reducing the operating frequency of the second semiconductor device 62, the consumption of extra power due to heat generation in the second semiconductor device 62 can be suppressed, and the cost required for heat countermeasures (installation of a heat sink or installation of a cooling fan with a large air volume). Is also suppressed.

  In the image reading apparatus 100 of the present embodiment, the first semiconductor device 61 and the second semiconductor device 62 each include an image processing circuit (an image processing circuit 641 and an image processing circuit 642), and the first drive signal generation unit 81 is The image processing circuit drive signal CLK11 for driving the image processing circuit 641 of the first semiconductor device 61 is generated at a predetermined frequency (statically fixed frequency), and the second drive signal generation unit 82 In order to drive the image processing circuit 642 of the second semiconductor device 62, the image processing circuit drive signal CLK11 is generated by the first drive signal generation unit 81 at a predetermined frequency (statically fixed frequency). The image processing circuit drive signal CLK21 having a slower frequency is generated. Accordingly, it is possible to suppress the consumption of extra power in the image processing circuit 642 that constitutes a part of the second semiconductor device 62 that performs image processing, and it is possible to suppress the cost required for heat countermeasures.

  In the image reading apparatus 100 of this embodiment, the first semiconductor device 61 and the second semiconductor device 62 each include an internal bus (an internal bus 681 and an internal bus 682), and the first drive signal generation unit 81 is set in advance. An internal bus drive signal CLK12 for driving the internal bus 681 of the first semiconductor device 61 is generated at a predetermined frequency (statically fixed frequency), and the second drive signal generation unit 82 In order to drive the internal bus 682 of the device 62, the internal frequency has a predetermined frequency (statically fixed frequency) and a frequency slower than the internal bus drive signal CLK12 generated by the first drive signal generation unit 81. A bus drive signal CLK22 is generated. As a result, it is possible to suppress the consumption of extra power in an internal internal bus that constitutes a part of the second semiconductor device 62 that performs image processing, and it is possible to suppress the cost required for heat countermeasures.

  The image reading apparatus 100 according to the present embodiment is connected to the first semiconductor device 61 so as to be communicable, and is used when the first semiconductor device 61 performs image processing. The memory generated by the first drive signal generation unit 81 is used. The first image memory 71 that operates at a speed corresponding to the frequency of the drive signal CLK13 and the second semiconductor device 62 are communicably connected to each other, and are used when the second semiconductor device 62 performs image processing. A second image memory 72 that operates at a speed corresponding to the frequency of the memory drive signal CLK23 generated by the signal generation unit 82, and the first drive signal generation unit 81 drives the first image memory 71. The memory drive signal CLK13 is generated, and the second drive signal generator 82 drives the second image memory 72 to drive a predetermined frequency (statically fixed). By the first drive signal generation section 81 a frequency) was to produce a memory drive signal 23 of the slower frequency than memory drive signal CLK13 to generate. Thereby, when the second semiconductor device 62 performs image processing, it is possible to suppress the consumption of extra power in the second image memory 72 that stores image data for image processing and image data after image processing. The cost required for heat countermeasures for the second image memory 72 can also be suppressed.

  In the image reading apparatus 100 according to the present embodiment, any one of the drive signal CLK2, the image processing circuit drive signal CLK21, the internal bus drive signal CLK22, and the memory drive signal CLK23 generated by the second drive signal generation unit 82 is used. It includes a setting unit (second frequency setting unit 92, main control unit 5) for setting one or a plurality of frequencies. Thereby, the frequency of various drive signals supplied to the second semiconductor device 62 and the structure related to the second semiconductor device 62 is sufficient for performing image processing, and for suppressing consumption of excess power and heat generation. It can be adjusted to a suitable frequency.

  In addition, the image reading apparatus 100 according to the present embodiment includes a document transport unit 2 that transports a document along the document transport path 24, and the first reading unit (first image sensor 12) is in the middle of the document transport path 24. The front side of the original is read, the second reading unit (second image sensor 21) reads the back side of the original in the middle of the original conveying path 24, and the first reading unit and the second reading unit simultaneously read one original. I do. Thereby, the document can be read simultaneously (in parallel) by the two reading units.

  Further, the image forming apparatus (multifunction peripheral 101) of the present embodiment forms an image based on image data that has been subjected to image processing by the image reading apparatus 100, the first semiconductor device 61, and the second semiconductor device 62. Part 4a. Accordingly, it is not necessary to separately develop two semiconductor devices in the image reading apparatus 100, and the development cost of the image forming apparatus (multifunction peripheral 101) on which the image reading apparatus 100 is mounted can be suppressed. Further, since the heat generated by the consumption of excess power in the second semiconductor device 62 can be suppressed, an image forming apparatus (multifunction peripheral 101) equipped with the image reading apparatus 100 with lower power consumption and lower cost than the prior art is provided. be able to.

  The embodiment of the present invention has been described above, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used for an image reading apparatus and an image forming apparatus including the image reading apparatus.

DESCRIPTION OF SYMBOLS 100 Image reading apparatus 101 Multifunction machine (image forming apparatus)
2 Document transport section 4a Image forming section 24 Document transport path 5 Main control section (setting section)
52 ROM (storage unit) 53 RAM (storage unit)
54 HDD (Storage Unit) 55 Storage Unit 12 First Image Sensor (First Reading Unit) 61 First Semiconductor Device 641 Image Processing Circuit 681 Internal Bus 71 First Image Memory 81 First Drive Signal Generation Unit CLK1 Drive Signal CLK11 Image Processing Circuit drive signal CLK12 Internal bus drive signal CLK13 Memory drive signal 21 Second image sensor (second reading unit) 62 Second semiconductor device 642 Image processing circuit 682 Internal bus 72 Second image memory 82 Second drive signal generation unit 92 Second frequency setting unit (setting unit) CLK2 Drive signal CLK21 Image processing circuit drive signal CLK22 Internal bus drive signal CLK23 Memory drive signal

Claims (7)

An image reading unit that includes a conveyance reading contact glass for reading a document passing through the upper surface, and a placement reading contact glass for reading the placed document, and reads the document to generate image data;
A document conveying unit that is provided above the image reading unit, conveys the document along the document conveying path, and conveys the document toward the conveyance reading contact glass;
A storage unit for storing image data ,
The image reading unit
A first reading unit for reading one side of the document;
A first drive signal generator for generating a drive signal;
It operates at which the first drive signal generation unit according to the frequency of the drive signal generated includes a first semiconductor device intends row image processing on the image data obtained by the original reading of the first reading portion,
The document conveying section is
A second reading unit for reading the other side of the document;
A second drive signal generator for generating a drive signal;
A second semiconductor device that operates at a speed corresponding to the frequency of the drive signal generated by the second drive signal generation unit and performs image processing on image data obtained by reading the document of the second reading unit;
The storage unit includes an HDD, and the HDD stores image data on which the first semiconductor device has been subjected to image processing and image data on which the second semiconductor device has been subjected to image processing,
The first semiconductor device stores another image data stored in the HDD in order to perform a print or transmission job in a state where image processing is performed on image data obtained by reading the document of the first reading unit. Perform parallel image processing to perform image processing in parallel,
The second semiconductor device does not perform the parallel image processing,
The first semiconductor device and the second semiconductor device have the same specifications and design ,
The image reading apparatus, wherein the second drive signal generation unit generates a drive signal having a slower frequency than the drive signal generated by the first drive signal generation unit.

The first semiconductor device and the second semiconductor device each include an image processing circuit,
The first drive signal generation unit generates an image processing circuit drive signal for driving the image processing circuit of the first semiconductor device at a predetermined frequency,
The second drive signal generation unit drives the image processing circuit of the second semiconductor device to drive the image processing circuit drive signal for the image processing circuit which has a predetermined frequency and is generated by the first drive signal generation unit. 2. The image reading apparatus according to claim 1, wherein a drive signal for an image processing circuit having a slow frequency is generated. The first semiconductor device and the second semiconductor device each include an internal bus;
The first drive signal generation unit generates an internal bus drive signal for driving the internal bus of the first semiconductor device at a predetermined frequency,
The second drive signal generation unit drives the internal bus of the second semiconductor device, and has a predetermined frequency and a frequency slower than the internal bus drive signal generated by the first drive signal generation unit. The image reading apparatus according to claim 1, wherein a drive signal for the internal bus is generated. The first semiconductor device is communicably connected and used when the first semiconductor device performs image processing, and operates at a speed corresponding to the frequency of the memory drive signal generated by the first drive signal generation unit. A first image memory;
The second semiconductor device is communicably connected, used when the second semiconductor device performs image processing, and operates at a speed corresponding to the frequency of the memory drive signal generated by the second drive signal generation unit. A second image memory,
The first drive signal generation unit generates a memory drive signal for driving the first image memory,
The second drive signal generation unit drives the second image memory, and has a predetermined frequency and a memory drive signal having a frequency lower than the memory drive signal generated by the first drive signal generation unit 4. The image reading apparatus according to claim 1, wherein the image reading apparatus generates an image.   A setting unit for setting one or a plurality of frequencies of the drive signal generated by the second drive signal generation unit, the image processing circuit drive signal, the internal bus drive signal, and the memory drive signal. The image reading apparatus according to claim 1, further comprising: Prior Symbol first reading unit reads the surface of the document in the course of the document conveying path, wherein the second reading unit is the middle reads the back side of the document of the document feed path, the second reading and the first reading unit The image reading apparatus according to claim 1, wherein the unit simultaneously reads one original.
  An image reading apparatus according to any one of claims 1 to 6, and an image forming unit that forms an image based on image data that has been subjected to image processing by the first semiconductor device and the second semiconductor device. An image forming apparatus comprising the image forming apparatus.

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