JP2010147920A - Image reading unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the reading image quality of double-sided reading, and also the reading productivity of single-sided reading, on the occasion of magnification zoom (resolution change). <P>SOLUTION: A image reading unit includes: a first image read means 100 provided with a reduction optical system for reading a surface image of the original document to be conveyed and converting it into surface image data; a second image reading means 109 equipped with an equal magnification optical system, for reading an image of the rear face of the original document to convert it into rear face image data; an electronic variable magnification means 602 for carrying out variable magnification processing of the image data; and a reading control means 603, wherein in the case of double-sided reading designation, the original document is conveyed at equal magnification line speed Vo and the images of front surface of the original document and the backside are read by the first and the second image reading means, and the surface image and backside image data are changed into indication scale factor by variable magnification processing, and in the case of single-sided reading designation, the original document is conveyed at line speed according to indication scale factor, and the image of front surface of the original document is read by the first image reading means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus used in a scanner, a digital copying machine, a facsimile, and the like and an image forming apparatus equipped with the image reading apparatus, and more particularly to setting of a sub-scanning speed corresponding to a reading magnification or resolution.

  2. Description of the Related Art Conventionally, an image reading apparatus represented by a copying machine or the like uses a reduction optical system that projects an image of an original on a contact glass onto an image sensor such as a CCD, and a mirror of the reduction optical system is driven in a sub-scanning manner (flat) Bed reading or book reading). A small image reading apparatus such as an original scanner or a facsimile uses an equal-magnification optical system including an LED (light emitting diode) array light source, a rod lens array, and a CIS (contact image sensor), and the original is driven in a sub-scanning manner (sheet). Through reading).

  Recently, a scanner that reads a flatbed with a reduction optical system and an automatic document feeder (ADF: document feeder) incorporating a unity magnification optical system are installed together, and the original is scanned with the reduction optical system. Double-sided scanning that reads the back side of the document with the same magnification optical system, sheet-through single-sided scanning that scans the surface of the document with only the reduction optical system, and flat that reads the surface of the document with flatbed scanning An image reading apparatus in a multiple reading mode that performs single-sided bed reading is becoming popular. FIG. 1 is a vertical sectional view showing a schematic configuration of such an image reading apparatus. A scanner 100 as a main body of the image reading apparatus includes a reduction optical system for reading the surface of an original, and the ADF 101 includes a back surface. Built-in equal magnification optical system. A document 111 placed on the document tray 112 is conveyed along a path indicated by an arrow in FIG. 1, and is reduced by a reduction optical system as a first reading unit and an equal magnification optical system as a second reading unit. In this configuration, both sides of the original are read by one original conveyance.

  The reduction optical system and the equal-magnification optical system have different reading characteristics. The former has a long optical path length from the original to the image sensor 102, so that the depth of focus is deep, and the read image data when the original floats from the contact glass 110. Deterioration (out-of-focus) is small. On the other hand, the latter is small, but the optical path length is short, and if the original is slightly lifted from the reading surface, the image data is greatly deteriorated (out of focus). When a double-sided original is read simultaneously with the image reading apparatus having such a configuration, the original is conveyed (sub-scanning drive).

JP 2006-245825 A JP 2004-187144 A Japanese Patent Application Laid-Open No. 2007-74367.

  The image reading apparatus of Patent Document 1 has a plurality of document reading modes, and executes an appropriate scaling process with little deterioration of a read image regardless of which reading mode is selected. The image reading apparatus disclosed in Patent Document 2 electronically drives a reduction optical system CCD at the reading speed of a contact image sensor of an equal magnification optical system during double-sided reading, and scan speed determined for the CCD during single-sided reading. The CCD is electronically read and driven. The image reading apparatus disclosed in Japanese Patent Laid-Open No. 2004-260260 has an optimum document conveyance speed (sub-scanning speed) for electronic reading driving of a CIS (contact image sensor) of an equal-magnification optical system when simultaneously reading the document front surface and document back surface. Set. Further, when only the document front surface or the document back surface is read, the document transport speed is set to be optimal for the electronic reading drive of each CCD or CIS.

  In sheet-through reading, since the document being conveyed is read, the document does not necessarily maintain the same reading height from the reading surface, and a case may occur where the document slightly floats. This is a matter related to the behavior of the document, and it is difficult to stabilize the behavior of the document and make the height from the reading surface constant as the conveyance speed range is wide, such as the document conveyance speed is fast or slow. When the behavior of the original is not stable, the read image data may be out of focus in the CIS for reading the back side of the original. In order to avoid this, there is a method of stabilizing the behavior of the document by narrowing the document conveyance speed to a narrow range. However, in the method of changing the magnification by changing the reading density in the sub-scanning direction by changing the document conveyance speed at the time of zooming, the conveyance speed increases at the time of reduction zooming, so that productivity is improved. Therefore, when the conveyance speed is limited to a low speed region, the reading productivity is lowered. When reading a single-sided document, the reduction optical system is used instead of the CIS, so even if the behavior of the document is slightly disturbed, it is difficult to show out-of-focus, but the conveyance speed is limited to a low-speed area, improving reading productivity. I can't hope. In particular, when an MFP (multifunction printer) having a scanner application function for transmitting original image data to an external terminal such as a personal computer, mobile phone, server, or printer is restricted to a low speed region, it is read at a low resolution (for example, 200 dpi). Since there are many opportunities, poor reading productivity becomes remarkable.

  In Patent Document 1, as a countermeasure against image quality deterioration caused by motor rotation unevenness at the time of enlargement / magnification, a threshold is set so that the reading linear velocity does not become a predetermined value or less for each reading mode. In this prior art, the motor rotation unevenness at the time of enlargement / magnification is taken into consideration, but no countermeasure against the out-of-focus due to the floating behavior of the document during conveyance is not presented. In Patent Documents 2 and 3, a reduction in reading productivity is reduced by changing the basic linear velocity corresponding to the driving of the CIS or CCD. No consideration is given to the case of reading with.

  An object of the present invention is to increase the read image quality of double-sided reading and the reading productivity of single-sided reading in the case of scaling or resolution change.

(1) Document conveying means (101);
A first image reading means (100) having a reduction optical system that reads an image on the surface of the original conveyed by the original conveying means and converts it into surface image data;
A second image reading means (109) provided with an equal-magnification optical system for reading an image on the back side of the original document conveyed by the original document conveying means and converting it into back surface image data;
Reading magnification instruction means (710,701);
Reading mode designating means (710, 701) for designating double-sided scanning or single-sided scanning;
Electronic scaling means (602) for scaling the image data read from the document; and
When double-sided scanning is designated, the original is conveyed at the same linear velocity (Vo) by the original conveying means, and the images on the front and back sides of the original are read by the first and second image reading means, The front side image data and the back side image data are scaled by the electronic scaling unit to the magnification designated by the scanning magnification instruction unit, and when single-sided scanning is designated, the original conveying unit designates A reading control unit (603) that conveys the document at a linear velocity corresponding to the magnification and reads the image on the surface of the document by the first image reading unit;
An image reading apparatus comprising:

  In double-sided scanning, the document is transported at the same linear velocity (Vo) regardless of the specified magnification, so by setting the same linear velocity (Vo) to a speed that does not cause floating behavior on the document. The read image quality is high, and scaling is performed by the electronic scaling means (602), for example, by thinning out (in the case of reduction) or interpolation (in the case of enlargement) of image data. In the case of single-sided reading, since the document is conveyed at a linear speed corresponding to the designated magnification, reading productivity is improved. This single-sided reading is performed by the first image reading unit having a reduction optical system that is less likely to be out of focus in the floating behavior of the document, so that the quality of the read image does not deteriorate.

  (2) The reading control means (603) indicates that when the single-sided reading is designated, the designated magnification is equal to or less than the magnification (B) corresponding to the minimum reading conveyance speed (Vmin). The document is transported at a speed corresponding to the minimum speed (Vmin), and at a magnification exceeding the magnification (B) corresponding to the minimum speed (Vmin), the original is driven at the minimum speed (Vmin) and the surface image data is converted by the electronic scaling unit. The image reading apparatus according to (1), wherein a scaling process is performed to the specified magnification.

  In the case of single-sided scanning, magnification is changed by changing the conveyance speed, or electronic scaling is applied to the shortage of the speed change. Can be obtained.

  (3) The first image reading means includes an image sensor (102) for converting a projection image into an image signal, and a sheet through reading window (106) facing the surface of the document conveyed by the document conveying means (101). A reduction projection reading apparatus comprising: illumination means for illuminating a light source; a mirror group for reflecting an image of the surface toward the image sensor (102); and a lens (103) for reducing and projecting the image reflected by the mirror group onto the image sensor. The image reading apparatus according to (1) or (2) above.

  (4) The reduction projection reader further includes a translucent plate (110) for flatly arranging the original, and a first reflecting first image of the surface of the mirror in contact with the translucent plate in the mirror group. A first carriage (105) mounted with a mirror and the illumination means, and a second mounted with second and third mirrors that reflect the image reflected by the first mirror in the mirror group to the image sensor (102). Driving means for driving the carriage (107) and the first and second carriages along the original with sub-scan driving with a constant image optical path from the original to the image sensor (102); The image reading apparatus according to 3).

  (5) The reading control means (603) instructs the first carriage (105) to specify the first and second carriages by the driving means when reading the image of the original on the light transmitting plate (110). The image reading apparatus according to (4), wherein the image reading device is driven at a speed corresponding to the linear speed corresponding to the magnification and reads an image on the surface of the document by the first image reading unit.

  (6) The reading control means (603) has a specified magnification when reading an image of a document on the light transmitting plate (110) so that the minimum speed (Vmin) of the reading drive of the first carriage (105). If the magnification is equal to or less than the corresponding magnification (B), the first carriage is driven at a speed opposite to the designated magnification, and if the magnification exceeds the minimum speed (Vmin) corresponding to the minimum speed (Vmin), the minimum speed (Vmin ), The first carriage is driven, and the electronic scaling unit scales the surface image data to the designated magnification; The image reading apparatus according to (5) above.

(7) Document conveying means (101);
A first image reading means (100) having a reduction optical system that reads an image on the surface of the original conveyed by the original conveying means and converts it into surface image data;
A second image reading means (109) provided with a magnifying optical system for reading an image on the back side of the document conveyed by the document conveying means and converting it into back image data;
Reading resolution instruction means (710,701);
Reading mode designating means (710, 701) for designating double-sided scanning or single-sided scanning;
Resolution conversion means (602) for converting the resolution of the image data read from the document; and
When duplex scanning is designated, the document is transported at the basic linear velocity (Vo) at which the basic resolution (P) is read by the document transporting means, and the surface of the document is scanned by the first and second image reading means. When the image on the back side and the back side image are read, the front side image data and the back side image data are converted by the resolution conversion unit to the resolution instructed by the reading resolution instruction unit, and the single side reading is designated, A reading control means (603) that conveys the document at a linear velocity associated with the instructed resolution by the conveying means, and reads an image on the surface of the document by the first image reading means;
An image reading apparatus comprising:

  (8) The reading control means (603) indicates that the instructed resolution is equal to or less than the resolution (F) corresponding to the minimum reading conveyance speed (Vmin) when single-sided reading is designated. When the document is transported at a speed opposite to the resolution, and the resolution exceeds the resolution (F) corresponding to the minimum speed (Vmin), the document is driven at the minimum speed (Vmin) and the surface image data is converted by the resolution conversion means. The image reading apparatus according to (7), wherein the image is converted into the designated resolution.

  (9) The first image reading means includes an image sensor (102) for converting the projected image into an image signal, and a sheet through reading window (106) facing the surface of the document conveyed by the document conveying means (101). A reduction projection reading apparatus comprising: illumination means for illuminating a light source; a mirror group for reflecting an image of the surface toward the image sensor (102); and a lens (103) for reducing and projecting the image reflected by the mirror group onto the image sensor. The image reading apparatus according to (7) or (8) above.

  (10) The reduction projection reader further includes a translucent plate (110) for flatly arranging the original, and a first reflecting first image of the surface of the mirror group in contact with the translucent plate. A first carriage (105) mounted with a mirror and the illumination means, and a second mounted with second and third mirrors that reflect the image reflected by the first mirror in the mirror group to the image sensor (102). Driving means for driving the carriage (107) and the first and second carriages along the original with sub-scan driving with a constant image optical path from the original to the image sensor (102); The image reading apparatus according to 9).

  (11) The reading control means (603) instructs the first carriage (105) to designate the first and second carriages by the driving means in the case of reading the image of the original on the light transmitting plate (110). The image reading apparatus according to (10), wherein the image reading device is driven at a linear velocity associated with the resolution and reads an image on the surface of the original by the first image reading unit.

  (12) In the reading control means (603), the instructed resolution when reading the image of the document on the light transmitting plate (110) is the minimum speed (Vmin) of the reading drive of the first carriage (105). If the resolution is less than or equal to the corresponding resolution (F), the first carriage is driven at a speed corresponding to the instructed resolution, and if the resolution exceeds the resolution (F) corresponding to the minimum speed (Vmin), the minimum speed (Vmin ) To drive the first carriage and convert the surface image data into the designated resolution by the resolution conversion means; the image reading apparatus according to (11) above.

(13) The image reading device (100, 101) according to any one of the containers (1) to (12);
Image data conversion means (602) for converting image data read from the document by the image reading device into image information that can be accepted by an external terminal;
A communication device (607) for transmitting image information to the external terminal; and
Means (701) for outputting the image information converted by the image data conversion means (602) to the communication device (607);
An image reading apparatus comprising:

(14) The image reading device (100, 101) according to any one of (1) to (12) above;
An image forming apparatus (1) for forming an image represented by the image data on a sheet; and
Image data processing means (602) for converting the image data read from the document by the image reading device into image data suitable for image formation by the image forming device (1);
An image forming apparatus comprising:

(15) Further, image data conversion means (602) for converting the image data read from the original by the image reading device into image information that can be accepted by the external terminal;
A communication device (607) for transmitting image information to the external terminal; and
The image forming apparatus according to (14), further including means (701) for outputting the image information converted by the image data converting means (602) to the communication apparatus (607).

  Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

  FIG. 1 shows a vertical cross section of an MFP equipped with the image forming apparatus of the first embodiment of the present invention. When the copy mode is designated by the user, the MFP reads an image of a document with the scanner 100 and / or ADF, and prints the read image with the printer 1. When the scanner (scanner distribution) mode is designated, the scanner 100 and / or the ADF reads an image of an original and stores it in an image storage memory or medium in the MFP or a designated external terminal (personal computer, mobile phone, server, external printer). , Accumulate (store) or send (distribute). In addition, when a print instruction is received from an external terminal, image information sent from the external terminal is printed.

  The image forming mechanism of the printer 1 includes known color electrophotographic forming process elements, and image forming cartridges 4k to 4K for printing each color of K (black), C (cyan), M (magenta), and Y (yellow). 4y is provided. Each cartridge is provided with a charging roller 6, a toner developing device 7 and a cleaner 9 around a drum-shaped photoconductor 5, and these image forming cartridges 4 k to 4 y are moved in the moving direction y of the transfer belt 3. They are arranged in tandem at a predetermined pitch along the (sub-scanning direction). Above the image forming cartridges 4k to 4y, there is a laser scanner 10, which projects each laser beam modulated by image data for each color image exposure onto each photosensitive drum 5 charged by the charging roller 6, and The scanning is repeated in the main scanning direction x orthogonal to the moving direction y of the transfer belt 3. As a result, an electrostatic latent image is formed on the photosensitive drum 5. The electrostatic latent image is visualized as a toner image by the developing unit 7. The respective color toner images on the respective photosensitive drums 5 are sequentially transferred onto the transfer belt 3 by the transfer roller 8 so as to represent the same color image. The overlapped toner images are transferred to the sheet fed from the registration roller 15 at the position of the secondary transfer roller 11. The sheet on which the toner image has been transferred is sent to the fixing device 17 through the delivery path 16, and is heated and pressurized by the fixing device 17, whereby the toner image is fixed to the sheet. The paper that has passed through the fixing unit 17 passes through a paper discharge path 18 and is delivered by a paper discharge roller 19 onto a paper discharge tray 20 outside the paper discharge outlet.

  When double-sided printing has been designated, when the paper that has passed through the fixing device 17 is sent out onto the paper discharge tray 20 outside the paper discharge port by the paper discharge roller 19 through the paper discharge path 18, Before the paper discharge roller 19 is disengaged, the forward rotation (paper discharge rotation) of the paper discharge roller 19 is stopped, and the paper discharge roller 19 is driven in reverse (reverse) while the paper tail edge is held between the paper discharge rollers 19. From the tail end of the sheet, the sheet is fed into a double-sided conveyance path (sheet discharge path 18, return reversing path 22, feeding roller 23, and reversing paper feeding path 25), and sent from the reversing paper feeding path 25 to the registration roller 15 to the registration roller 15. Stop after hitting. Then, in accordance with the movement of the transfer belt 3, the leading edge of the sheet reaches the secondary transfer roller 11 when the leading end (image leading edge) of the toner image transferred onto the transfer belt 3 reaches the secondary transfer roller 11. The feeding driving of the registration roller 15 is started. Then, the sheet on which the toner image is transferred to the reversed surface is sent to the fixing unit 17 through the feeding path 16, and is heated and pressurized by the fixing unit 17, whereby the toner image is fixed to the sheet. The paper that has passed through the fixing unit 17 passes through a paper discharge path 18 and is delivered by a paper discharge roller 19 onto a paper discharge tray 20 outside the paper discharge outlet. The sheet is fed from the sheet feeding tray 12 to the sheet feeding path 14 by the sheet feeding roller 13 and abuts against the registration roller 15, and then temporarily stops. Then, the sheet is moved by the registration roller 15 in accordance with the movement of the toner image on the transfer belt 3. It is sent out to the transfer roller 11.

  The scanner 100 which is the main body of the image reading apparatus has a reduction optical system of first image reading means for reading the surface of the original. The reduction optical system is reflected by a first carriage 105 including a light source that illuminates the original, a reflector that collects light from the light source on the original, and a first mirror that receives reflected light from the original, and the first mirror. There is a second carriage 107 equipped with first and second mirrors that reflect the reflected light toward a lens 103 that collects the light on a CCD (charge coupled device) that is an image sensor, and the lens 103 and the CCD 102. In addition, the scanner 100 includes a reference white plate 104, a window glass 106 for reading through a sheet, and a contact glass 110 for reading a flat bed (for reading a book).

  On the other hand, the ADF 101 includes an equal-magnification optical system (CIS 109) which is a second image reading unit that reads the back surface. In addition, the ADF 101 includes a white roller 108, a document tray 112, a pickup roller that separates the documents stacked on the document tray 112 one by one, a transport roller for transporting the documents, and the like. The white roller 108 covers the entire length in the main scanning direction x of the window glass 106 in order to obtain correction data at the time of shading correction when the back side of the document is read by the CIS 109 of the equal-magnification optical system as the second image reading unit. An almost white roller of uniform density over the entire length.

  In the case of flat bed reading, the first carriage 105 is moved rightward (y arrow in FIG. 1) from a position (home position) immediately below the window glass 106 shown in FIG. 1 by a motor (not shown) as a driving source. The second carriage 107 is driven in the same direction at half the moving speed of the first carriage 105 in synchronism with this. That is, the second carriage 107 is driven so that the path of the original reflected light from the upper surface of the contact glass 110 to the CCD 102 is constant. The CCD 102 converts the image light into an image signal from the time when the first carriage 105 (the first mirror) reaches just below the start end (left end in FIG. 1) to the end (right end) of the document. The signal is digitally converted by the signal processing circuit 601 (FIG. 2). That is, it is converted into image data. The reference white plate 104 is provided to obtain correction data at the time of shading correction in the case of flat bed reading, and has a uniform density over the entire length of the entire width of the contact glass 110 (x direction). It is a white member.

  In the case of reading the document surface image by sheet-through reading, the first carriage 105 is placed at the home position shown in FIG. 1, the document is conveyed by the ADF 101, and the CCD 102 displays the image while the document crosses the window glass 106. Light is converted into an image signal, and the signal processing circuit 601 digitally converts the image signal.

  In the case of double-sided reading, the image on the back side of the document is read by the CIS 109 of the equal-magnification optical system along with the reading of the image on the surface of the document by the sheet-through reading.

  FIG. 2 shows an outline of an electric control system equipped in the MFP shown in FIG. The output signal R / G / B of the CCD 102 of the scanner 100 is converted into image data (digital data) by the signal processing 601, and in the case of reading the mode image in the copy mode, the image processing 602 of the printer controller 700 converts the printer 1 Is converted into image data C / M / Y / K for image formation and output to the printer 1. In the case of image reading in the scanner mode, an image processing 602 converts the image information into a form requested by a PC (personal computer) or other external terminal that requested the image, and an external I / F (interface) that is a communication circuit. Transmit to an external terminal via 607. In the case of reading an image in the storage mode, the image processing 602 converts the image information into a storage form image information, and the image memory (semiconductor memory module) or the electronic information storage medium (for example, hard disk HD) in the image processing 602 Store (write) in The image information of the print instruction received from the external terminal by the external I / F 607 is temporarily stored in the image memory in the image processing 602, converted into image data for image formation of the printer 1 by the image processing 602, and sent to the printer 1. Output.

  The scanner control 603 controls the operation of the scanner 100, performs a sub-scan driving of the carriage by flatbed reading, drives a scanner motor including a stepping motor and a driver, mechanically drives a reduction optical system, Control of signal processing 601 and image processing 602 for processing the CCD output signal, lighting control of the illumination light source on the first carriage 105 via the lamp stabilizer 604, communication with the system control 701 and the ADF control 605, etc. I do.

  In the flat bed reading mode, the scanner 100 performs sub-scan driving of the carriages 105 and 107 by a stepping motor to read the original on the reference white plate 104 and the contact glass. A scanner control 603 for controlling the stepping motor (sub-scanning timing) sends a drive control signal (a signal for setting a motor current: M_VREF0 to 2, a signal for setting a motor excitation method) to a scanner motor 608 (a motor driver thereof). M_MODE0 to 1 and a signal indicating the rotation direction: CW_CCW and a clock for driving the motor: M_CLK) are output.

  In addition, the scanner control 603 outputs a signal indicating black offset detection timing: XBKDT, a signal indicating reference white plate reading timing: XSHGT, and a signal indicating document reading timing: XFGATE to the signal processing 601 to stabilize the lamp. A lighting synchronization clock: L_CLK and a lighting signal: L_CNT are output to the device 604.

  In the sheet-through reading mode, the first carriage 105 of the reduction optical system is driven from the sheet original reading window glass 106 (home position) to the reference white plate 104 to read the reference white plate 104 and return to the reading window glass 106, where Scan the document surface. In this reading mode, since the ADF control 605 manages the document conveyance timing, a signal XDFGATE indicating the document surface reading timing is output to the scanner control 603. The scanner control 603 passes it to the signal processing 601 and the image processing 602 as XFGATE. In the double-sided reading mode for sheet-through reading, the back side is read by the CIS 109, but the ADF control 605 has a signal indicating the black offset detection timing of the CIS 109: XBKDT2, a signal indicating the reading timing of the white roller 108: XSHGT2, and A signal indicating the document back side reading timing: XFGATE 2 is transmitted to the signal processing 601.

  As shown in FIG. 3, the operation board 609 includes a function selection button 701, an LCD 702 for displaying information contents and touch input, a switch 703 including a numeric keypad and a start button. The information content display LCD 702 also incorporates a touch sensor function, from which a copy magnification can be input when using a copy, and a reading resolution when using a scanner application. The operation board 609 is connected to the system control 701 by serial communication. Based on the input of the operation board 609, the system control 701 generates scanner and ADF control information and supplies it to the scanner control unit 603.

  FIG. 4 shows an outline of document reading control by the scanner control 603 in the copy mode. When there is a reading request (s1), the scanner control 603 determines the reading mode (s2, s6). If the reading request is duplex scanning and there is a document on the document tray 112, the scanning request is determined to be duplex scanning mode. If the reading request is single-sided reading (no double-sided reading specified) and there is a document on the document tray 112, it is determined to be single-sided reading (front surface reading) by sheet-through scanning. It is determined as single-sided reading.

  When the double-sided reading mode is determined, the scanner control 603 uses the ADF 101 to separate one document on the document tray 112 by the pickup roller, and the conveyance roller to the same speed (linear speed Vo (mm regardless of the specified reading magnification). / s)) and transports the glass so as to pass through the position of the window glass 106. Here, the front surface of the document is read by the CCD 102 of the scanner 100, and the document is further conveyed at the same linear velocity Vo (mm / s), and the back surface of the document is read by the CIS 109 of the equal magnification optical system (s3). If the designated magnification is not equal, the image processing 602 uses the electronic scaling such as three-dimensional convolution on the read image data to thin out the image data (in the case of reduction) or interpolation. (In case of enlargement) This is applied to both the main scanning direction X and the sub-scanning direction (s5).

  When it is determined that one-side reading by sheet-through reading is performed, the specified magnification Y% is referred to. When the same magnification is specified, the document is positioned at the window glass 106 position by the ADF 101 at the same linear velocity Vo (mm / s). Transport to pass through. Here, the surface of the original is read by the CCD 102 of the scanner 100 (s6, s7). If the designated magnification Y is not equal, if the designated magnification is equal to or less than the magnification B% determined as the minimum linear velocity in sheet-through reading, the ADF 101 scans the original with a linear velocity corresponding to the designated magnification Y%. It is conveyed so as to pass through position 106. Here, the surface of the original is read by the CCD 102 of the scanner 100 (s8, s9). The read image data is thinned (in the case of reduction) or interpolated (in the case of enlargement) only in the main scanning direction X using electronic scaling such as three-dimensional convolution (s10). ). When the designated magnification Y% exceeds the magnification B% determined as the minimum linear velocity in sheet-through reading, the document is conveyed by the ADF 101 so as to pass the position of the window glass 106 at the minimum linear velocity corresponding to the magnification B%. Here, the surface of the original is read by the CCD 102 of the scanner 100 (s11). Since the designated magnification Y% exceeds the magnification B% at the minimum linear velocity, interpolation (enlargement) is performed on the read image data using electronic scaling such as three-dimensional convolution. In the main scanning direction X, interpolation (enlargement) is performed with the specified magnification Y% (s12).

  If it is determined that the single-side reading is performed by flat bed reading, the scanner control 603 performs sub-scan driving of the first and second carriages 105 and 107 of the reduction optical system, and the CCD 102 of the scanner 100 performs scanning on the contact glass 110. Scan the original. The setting of the sub-scanning speed and the scaling process of the image data in this case are the same as in the case of single-sided reading by sheet-through reading (s6 to s12).

FIG. 5 shows the upper limit scaling factor (B%) exceeding the same magnification (100%) and further exceeding the scaling factor (B%) corresponding to the lowest linear velocity Vmin from the lower limit scaling factor (A%) corresponding to the highest linear velocity Vmax of image reading. C.) is a reading linear velocity V (sub-scanning velocity). The linear velocity V in the case of double-sided document reading is the same linear velocity, that is, the basic linear velocity Vo (mm / s), regardless of the reading magnification Y%. The linear velocity for single-sided original reading is changed according to the reading magnification Y% as follows:
When A% ≦ Y% ≦ B%, the linear velocity V is V = (Vo × 100% / Y%) (mm / s)
At this time, since reading is performed with the CCD 102 processing time for one line: main scanning processing time fixed, the amount of data in the sub-scanning direction of the read image is inversely proportional to the reading linear velocity V, so the linear velocity is changed. Thus, a zoomed image is obtained. Scaling in the main scanning direction is performed by image processing 602.
When B% <Y% ≦ C%, the linear velocity V is V = (Vo × 100% / B%) (mm / s)
In this case, since the amount of data in the sub-scanning direction of the image is insufficient simply by changing the reading speed, the image processing 602 also performs scaling in the sub-scanning direction.

  FIG. 6 shows an outline of document reading control by the scanner control 603 in the scanner application mode. When there is a reading request (s1), the scanner control 603 determines the reading mode (s2, s6a). If the reading request is duplex scanning and there is a document on the document tray 112, the scanning request is determined to be duplex scanning mode. If the reading request is single-sided reading (no double-sided reading specified) and there is a document on the document tray 112, it is determined to be single-sided reading (front surface reading) by sheet-through scanning. It is determined as single-sided reading.

  When the double-sided reading mode is determined, the scanner control 603 uses the ADF 101 to separate one document on the document tray 112 by a pickup roller, and uses a transport roller to set a reference dpi linear velocity (linear velocity Vo regardless of the designated reading resolution dpi). (Mm / s)) so as to pass through the window glass 106 position. Here, the front surface of the original is read by the CCD 102 of the scanner 100, and further, the original is conveyed at a reference dpi linear velocity Vo (mm / s), and the back side of the original is read by the CIS 109 of the equal magnification optical system (s3a). If the designated resolution is not the reference dpi, the image processing 602 thins out the image data using electronic resolution conversion such as three-dimensional convolution on the read image data (in the case of low resolution conversion). Alternatively, interpolation (in the case of high resolution conversion) is performed. This is applied to both the main scanning direction X and the sub-scanning direction (s5a).

  When it is determined that one-sided scanning is performed by sheet-through scanning, the designated resolution Zdpi is referred to. When the standard resolution is designated, the document is passed through the window glass 106 position by the ADF 101 at the standard linear velocity Vo (mm / s). Transport as you do. Here, the surface of the original is read by the CCD 102 of the scanner 100 (s6a, s7a). If the designated resolution Zdpi is not equal, if the designated resolution Zdpi is less than the magnification B% determined as the minimum linear speed in sheet-through reading, the ADF 101 scans the document at the linear speed corresponding to the designated resolution Zdpi. It is conveyed so as to pass through position 106. Here, the surface of the original is read by the CCD 102 of the scanner 100 (s8a, s9a). Using the electronic scaling such as three-dimensional convolution on the read image data, thinning out the image data (in the case of low resolution conversion) or interpolation (in the case of high resolution conversion) only in the main scanning direction X (S10a). When the designated resolution Zdpi exceeds the resolution Fdpi determined as the minimum linear velocity Vmin in sheet-through reading, the document is conveyed by the ADF 101 so as to pass through the position of the window glass 106 at the minimum linear velocity Vmin corresponding to the resolution Fdpi. Here, the surface of the original is read by the CCD 102 of the scanner 100 (s11a). Since the designated resolution Zdpi exceeds the resolution Fdpi at the minimum linear velocity Vmin, the scanned image data is sub-scanned by interpolation (high resolution conversion) using electronic resolution conversion such as three-dimensional convolution. Interpolation (high resolution conversion) is performed with the designated resolution Zdpi for the main scanning direction X (s12a).

  If it is determined that the single-side reading is performed by flat bed reading, the scanner control 603 performs sub-scan driving of the first and second carriages 105 and 107 of the reduction optical system, and the CCD 102 of the scanner 100 performs scanning on the contact glass 110. Scan the original. In this case, the setting of the sub-scanning speed and the scaling process of the image data are the same as in the case of single-sided reading by sheet-through reading (s6a to s12a).

FIG. 7 shows the reading linear velocity V (sub-scanning velocity) from the lower limit resolution Edpi corresponding to the maximum linear velocity Vmax of image reading to the upper limit resolution Gdpi exceeding the reference resolution Pdpi and exceeding the resolution Fdpi corresponding to the lowest linear velocity Vmin. It is shown. The linear velocity V in the case of double-sided document reading is the linear velocity of the reference resolution Pdpi, that is, the basic linear velocity Vo (mm / s), irrespective of the reading resolution Zdpi. The linear velocity for single-sided original reading is changed according to the reading resolution Zdpi as follows:
When E ≦ Z ≦ F, the linear velocity V is V = (Vo × P / Z) (mm / s)
At this time, since reading is performed with the CCD 102 processing time for one line: main scanning processing time fixed, the amount of data in the sub-scanning direction of the read image is inversely proportional to the reading linear velocity V, so the linear velocity is changed. Thus, an image with a changed resolution can be obtained. Scaling in the main scanning direction is performed by image processing 602.
When F <Z ≦ G, the linear velocity V is V = (Vo × P / F) (mm / s)
In this case, since the amount of data in the sub-scanning direction of the image is insufficient simply by changing the reading speed, the image processing 602 also performs resolution conversion in the sub-scanning direction.

1 is a vertical sectional view of a multifunction printer MFP equipped with an image reading apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing an outline of an electric system equipped in the MFP shown in FIG. 1. FIG. 3 is a plan view of an operation board 710 shown in FIG. 2. 6 is a flowchart showing an outline of document reading control in a copy mode by the scanner control 603 shown in FIG. 2. 6 is a graph showing a sub-scanning speed (linear speed) set by the document reading control. 6 is a flowchart showing an outline of document reading control in a scanner application mode by the scanner control 603 shown in FIG. 2. 6 is a graph showing a sub-scanning speed (linear speed) set by the document reading control.

Explanation of symbols

1: Printer 2: Belt cleaner 3: Transfer belt 4 (4k to 4y): Image forming cartridge 5: Photoconductor drum 6: Charging roller 7: Developer 8: Primary transfer roller 9: Photoconductor cleaner 10: Laser scanner 11: secondary transfer roller 12: paper feed tray 13: paper feed roller 14: registration sensor 15: registration roller 16: delivery path 17: fixing device 18: paper ejection path 19: paper ejection roller 20: paper ejection tray 21: discharge Paper sensor 22: Return reversing path 23: Feeding roller 24: Reversing paper sensor 25: Reversing paper feeding path 102: CCD
103: Lens 104: Reference white plate 105: First carriage 106: Window glass 107: Second carriage 108: White roller 109: CIS
110: Contact glass 111: Document 112: Document tray

Claims (15)

Document transport means;
A first image reading unit including a reduction optical system that reads an image on the surface of the document conveyed by the document conveying unit and converts the image into surface image data;
A second image reading unit including a 1 × optical system that reads an image on the back side of the document conveyed by the document conveying unit and converts the image into back image data;
Reading magnification instruction means;
Reading mode designation means for designating double-sided scanning or single-sided scanning;
Electronic scaling means for scaling the image data read from the document; and
When double-sided scanning is designated, the original is conveyed at the same linear speed by the original conveying means, and the images on the front and back sides of the original are read by the first and second image reading means. When the single-side scanning is designated by the electronic magnification unit, the magnification is instructed by the document conveying unit. A reading control unit that conveys the document at a linear velocity associated with the first image reading unit and reads an image on the surface of the document by the first image reading unit;
An image reading apparatus comprising:   The reading control means conveys the document at a speed corresponding to the instructed magnification in a case where the designated magnification when the single-sided reading is designated is equal to or smaller than the magnification corresponding to the minimum speed of the reading conveyance. 2. The image reading apparatus according to claim 1, wherein at a magnification exceeding a minimum speed compatible magnification, the original is driven at the minimum speed and the surface image data is scaled to the designated magnification by the electronic scaling unit.   The first image reading means includes an image sensor that converts a projected image into an image signal, an illumination means that illuminates the surface through a sheet-through reading window facing the surface of the document conveyed by the document conveying means, and an image of the surface as the image. 3. The image reading apparatus according to claim 1, wherein the image reading apparatus includes a mirror group that reflects toward the sensor and a lens that reduces and projects an image reflected by the mirror group onto the image sensor.   The reduction projection reader further includes a translucent plate on which the original is placed flat, a first mirror that first reflects an image of a surface of the mirror group in contact with the translucent plate, and the illumination unit. A first carriage mounted; a second carriage mounted with second and third mirrors that reflect the image reflected by the first mirror in the mirror group to the image sensor; and the first and second carriages; 4. The image reading apparatus according to claim 3, further comprising: a driving unit that performs sub-scanning driving along the original with a constant image optical path from the original to the image sensor.   In the case of reading an image of a document on the translucent plate, the reading control means sets the first and second carriages to linear speeds corresponding to the magnifications designated by the first carriage by the driving means. The image reading apparatus according to claim 4, wherein the image reading apparatus is driven at a speed and reads an image on the surface of the original by the first image reading means.   The reading control means reversely corresponds to the instructed magnification when the instructed magnification when reading the image of the document on the light transmitting plate is equal to or less than the magnification corresponding to the minimum speed of the reading drive of the first carriage. The first carriage is driven at a speed that exceeds the minimum speed, and the first carriage is driven at the minimum speed and the surface image data is scaled to the designated scale by the electronic scaling means. 6. The image reading device according to claim 5, wherein the image reading device is processed. Document transport means;
A first image reading unit including a reduction optical system that reads an image on the surface of the document conveyed by the document conveying unit and converts the image into surface image data;
A second image reading unit including a 1 × optical system that reads an image on the back side of the document conveyed by the document conveying unit and converts the image into back image data;
Reading resolution instruction means;
Reading mode designation means for designating double-sided scanning or single-sided scanning;
Resolution conversion means for performing resolution conversion processing on the image data read from the document; and
When duplex scanning is designated, the document is transported at the basic linear velocity (Vo) at which the basic resolution (P) is read by the document transporting means, and the surface of the document is scanned by the first and second image reading means. When the image on the back side and the back side image are read, the front side image data and the back side image data are converted by the resolution conversion unit to the resolution instructed by the reading resolution instruction unit, and the single side reading is designated, A reading control unit that transports the document at a linear velocity associated with the instructed resolution by the transport unit, and reads an image on the surface of the document by the first image reading unit;
An image reading apparatus comprising:   The reading control means conveys the document at a speed opposite to the instructed resolution if the instructed resolution is less than or equal to the resolution corresponding to the minimum speed of reading and conveying when single-sided reading is designated, The image reading apparatus according to claim 7, wherein at a resolution exceeding a resolution corresponding to the minimum speed, the document is driven at the minimum speed and the surface image data is converted to the designated resolution by the resolution conversion unit.   The first image reading means includes an image sensor that converts a projected image into an image signal, an illumination means that illuminates the surface through a sheet-through reading window facing the surface of the document conveyed by the document conveying means, and an image of the surface as the image. The image reading apparatus according to claim 7 or 8, wherein the image reading apparatus includes a mirror group that reflects toward the sensor and a lens that reduces and projects an image reflected by the mirror group onto the image sensor.   The reduction projection reader further includes a translucent plate on which the original is placed flat, a first mirror that first reflects an image of a surface of the mirror group in contact with the translucent plate, and the illumination unit. A first carriage mounted; a second carriage mounted with second and third mirrors that reflect the image reflected by the first mirror in the mirror group to the image sensor; and the first and second carriages; The image reading apparatus according to claim 9, further comprising: a driving unit configured to perform sub-scanning driving along the document with a constant image optical path from the document to the image sensor.   In the case of reading an image of a document on the light-transmitting plate, the reading control unit sets the first and second carriages to the linear speed corresponding to the resolution designated by the first carriage by the driving unit. The image reading apparatus according to claim 10, wherein the image reading apparatus is driven at a speed and reads an image on the surface of the original by the first image reading means.   The reading control means reversely corresponds to the instructed resolution when the instructed resolution in reading the image of the document on the translucent plate is equal to or less than the resolution corresponding to the minimum speed of the reading drive of the first carriage. The first carriage is driven at a speed that exceeds the resolution corresponding to the minimum speed, and the first carriage is driven at the minimum speed and the surface image data is converted into the designated resolution by the resolution conversion means; The image reading apparatus according to claim 11. The image reading apparatus according to claim 1;
Image data conversion means for converting image data read from a document by the image reading device into image information that can be accepted by an external terminal;
A communication device for transmitting image information to the external terminal; and
Means for outputting the image information converted by the image data conversion means to the communication device;
An image reading apparatus comprising: The image reading apparatus according to claim 1;
An image forming apparatus that forms an image represented by the image data on a sheet; and
Image data processing means for converting image data read from the document by the image reading device into image data suitable for image formation by the image forming device;
An image forming apparatus comprising: And image data conversion means for converting image data read from the document by the image reading device into image information that can be received by an external terminal;
A communication device for transmitting image information to the external terminal; and
The image forming apparatus according to claim 14, further comprising: a unit that outputs the image information converted by the image data conversion unit to the communication device.

Images