JP5233625B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  According to the present invention, one of a document and an illumination light source for illuminating the document is sub-scanned with respect to the other, and the reflected light of the document is projected onto an image sensor to obtain an analog electrical signal having a main scanning line length from the image sensor The present invention relates to an image reading apparatus that converts digital data, that is, image data, and more particularly, to shading correction that corrects variations in image data in a main scanning line due to deterioration of an illumination light source, an image sensor, and optical elements interposed therebetween. The present invention can be implemented in a document image reading apparatus, a copying machine, and a facsimile apparatus.

  As this type of image reading apparatus, there are a flat bed reading type as shown in FIG. 13, a sheet through reading type as shown in FIG. 14, and an apparatus that selectively executes both types (for example, FIG. 10).

JP 2005-197892 A Japanese Patent Application Laid-Open No. 2008-103826.

  Patent Document 1 describes a reading apparatus that selectively executes both a flat bed reading method and a sheet-through reading method. It describes that the white surface of a white roller for supporting the back side of the document is used instead of the white reference plate used for the shading correction in the sheet-through method. In Patent Document 2, in addition to the first reference white plate 239A used for shading correction, a second reference white plate 239B is provided at the end of the main scanning line for document reading. This is used for determining whether or not the gain adjustment of the variable gain amplifier for amplifying the read image signal is necessary.

  In the scanning operation of the reduction optical system of the flat-bed reading type image reading apparatus shown in FIG. 13, the first carriage moves in the sub-scanning direction during reading of the pressure plate, and the reflection from the document on the contact glass 231 is performed as document information. The light is read, and the reflected light is imaged on a photoelectric conversion element (CCD) 207 that is an image sensor via a lens 236, and converted into an analog electric signal by photoelectric conversion in the photoelectric conversion element 207. The light intensity profile is adjusted in such a manner that the light from the scanner lamp 232 is reflected by the reflector and hits the original. The obtained analog electrical signal is subjected to analog processing and digital processing to read image information as digital data, that is, image data. Further, shading correction is performed in order to make the white reading level in the main scanning direction on the original uniform, and the reading data of the reference white plate 239A for that purpose is acquired every time before the original is scanned. At the time of sheet-through reading, as shown in FIG. 14, the first carriage moves immediately below the reference white plate 239A before the document is sent to the reading surface by the sheet-through conveyance drum 244, and then moves to the document reading surface. Is in the form of reading.

  By the way, at the time of sheet-through reading (during continuous reading of a plurality of originals), the reading operation of the reference white plate 239A for performing shading correction is not performed for each original to ensure productivity depending on the model. It is performed once per sheet or only once every few minutes, and for other documents, the reading operation time of the reference white plate 239A is omitted by performing shading correction using the previously acquired reference white plate data. We are trying to shorten it. This is called intermittent shading. In the case of intermittent shading, digital reference whiteboard data is calculated from the acquired reference whiteboard actual measurement value data by the number of data for one line. The reference white plate data or the correction coefficient for making the reference white plate data uniform is stored in a memory or the like in the shading correction circuit, and is read from the memory in the shading correction circuit or the like when reading a document. Perform shading correction of document data. In the case of flat bed reading, the reference white plate 239A is read in the process of sub-scanning the first carriage from the position shown in FIG. 14, that is, the home position, directly below the contact glass 231 on which the document shown in FIG. The read reference white plate data or a correction coefficient for making the reference white plate data uniform is stored in a memory or the like in the shading correction circuit.

  However, during continuous reading of multiple originals with intermittent shading, the reading level of the original decreases due to a short-term decrease in the amount of light due to the heat generated by the continuous lighting of the scanner lamp, and the first time when shading correction is performed using the same reference white plate data There may be a problem that a density difference occurs in the output image as the original from the last to the last. There is also an image reading apparatus that improves productivity by reading a white roller for sheet-through paper conveyance just above the reading surface instead of the reference white plate between papers and omitting the reference white plate reading operation (Patent Document 1). Further, there is a concern that vertical streaks may occur in the output document during the job due to the influence of dust adhering to the sheet-through reading surface glass or the white roller between sheets when reading a plurality of sheet-through documents.

  The first object of the present invention is to reduce the time required for generating correction reference data to be given to shading correction, and secondly to efficiently generate correction reference data to be given to shading correction for each document read. Objective.

(1) Sub-scanning means (244, 224, 238) for sub-scanning one (232) of the original and the illumination light source (232) for illuminating the original with respect to the other;
An image sensor (207) for converting the projected light image into an electrical signal, that is, an image signal, and outputting it for each main scanning line;
Optical means (233-236) for projecting reflected light of the document onto the image sensor;
Image signal processing means (209) for converting an electrical signal output from the image sensor into digital data, that is, image data;
A shading correction means (217) for correcting the image data of the document using shading correction data addressed to each pixel on the main scanning line based on the correction reference plane data (L ′ (n) );
The reference surface (239f) located in the field of view where the illumination light source, image sensor, optical means and image signal processing means generate image data of one main scanning line for document reading and at the end of the one main scanning line. , 239l);
When the original is read, the reading field in which the original is located is covered with the reference plane, and when the image data is acquired for each of the illumination light source illuminances having different values, the plurality of reference plane image data (Rf0-Rft, S0 ( L) -St (L)) or reference illuminance data (Table 2 Rf0, Rf0 / Rf0-Rft / Rf0, Rl0, resulting RL0 the reference surface data is / Rl0-Rlt / Rl0), each reference surface data each reference plane image data when the (Table 1 S (L) -St (L) ) or reference plane illuminance data (Table 2 S0 (L), S0 (L ) / S (L) -St (L) / S0 (L)) , the characteristic memory (221) storing the reference plane data in association with each other ; and
Prior to reading of the document, generates the reference surface data by reading the reference plane, with reference to the data of the characteristics memory, generated reference Mende over data corresponding reference Mende chromatography data (L '(n) ) To provide the shading correction means as the correction reference plane data to the reference data generation means (218);
An image reading apparatus comprising:

  In addition, in order to make an understanding easy, the symbol of the corresponding element or the corresponding matter of the Example which is shown in drawing and mentioned later in parentheses is attached for reference as an example.

Since the reference surface is in the field of view where the illumination light source, the image sensor, the optical means, and the image signal processing means generate image data of one line of main scanning for reading the document, these are driven to the position of the reference white plate as in the prior art. It is not necessary to read the reference surface. Then, the reference Mende over data obtained by said reading, based on the reference Mende over data and the reference plane data on the characteristics memory, so derives the compensation reference surface data of the reference Mende over data-enabled read, The time required to generate the correction reference plane data (L ′ (n)) can be shortened, and correction reference plane data used for shading correction can be efficiently generated for each document read. Due to this shading correction for each original read, even if there is dirt on the optical path from the illumination light source to the image sensor, or even if there is a change in the light amount of the illumination light source over time, there is a possibility that a smear image or vertical stripe will appear in the read output image This reduces the possibility that a density difference will occur in the output image as the first document is changed to the last document in sequential sequential reading of a plurality of documents.

(2) Sub-scanning means (244, 224, 238) for sub-scanning one (232) of the original and the illumination light source (232) for illuminating the original with respect to the other;
An image sensor (207) for converting the projected light image into an electrical signal, that is, an image signal, and outputting it for each main scanning line;
Optical means (233-236) for projecting reflected light of the document onto the image sensor;
Image signal processing means (209) for converting an electrical signal output from the image sensor into digital data, that is, image data;
A shading correction means (217) for correcting the image data of the document using shading correction data addressed to each pixel on the main scanning line based on the correction reference plane data (L ′ (n) );
The reference surface (239f) located in the field of view where the illumination light source, image sensor, optical means and image signal processing means generate image data of one main scanning line for document reading and at the end of the one main scanning line. , 239l);
A reference plane (239A) that is located away from the reference plane in the sub-scanning direction and extends in the main scanning direction length of the original reading field;
When multiple values acquired image data of the reference surface and the reference surface per each of the different illumination source light illumination, the plurality of reference plane image data (Table 1 Rf0-Rft, S0 (L) -St (L) Or reference surface data (Rf0, Rf0 / Rf0-Rft / Rf0, Rl0, Rl0 / Rl0-Rlt / Rl0 in Table 2) and reference surface image data (S (L) -St in Table 1) which are reference surface illuminance data (L)) or reference surface data (S0 (L), S0 (L) / S (L) -St (L) / S0 (L) in Table 2) that is reference surface illuminance data is stored in association with each other . Characteristic memory (221); and
Prior to reading of the original of the first mode (speed priority), to generate a reference surface data by reading the reference surface, the characteristic data referring to the memory, generated reference Mende over data corresponding reference Mende chromatography data (L '(n)) to derive supplied to the shading correction unit as the correction reference plane data, prior to reading of the original of the second mode (image quality priority), the reference Mende reading said reference surface over providing data to (L '(n)) to said shading correction unit as the correction reference surface data, the reference data generating means (218);
An image reading apparatus comprising:

In addition to the effects described in the above (1), prior to the reading of the original of the second mode (image quality priority), the reference plane the reference Mende over data by reading the (239A) (L '(n)) corrected standard A second mode (image quality priority) to be given to the shading correction means as surface data can be selected. Since the second mode produces the actual reference Mende over data read reference plane (239A) (L '(n )), can be expected higher accuracy shading correction.

(3) the reference data generating means (218) is of the characteristic memory and reference Mende chromatography data generated by reading the reference plane, first the reference surface data read said the adjacent pair located between and the ratio of the difference between the second reference Mende over data, the characteristic first and second memory of the reference surface data in the first and second are respectively associated with reference Mende over data If, given to the shading correction unit by interpolation, as the correction reference surface data to derive the reference surface data corresponding to the read reference Mende chromatography data (L '(n)) using a; (1) Or the image reading apparatus according to (2).

(4) See Mende over data on the characteristics memory is a reference plane image data (Table 1 Rf0-Rft, S0 (L) -St (L)); any of the above (1) to (3) The image reading apparatus according to claim 1.

To the reference plane image data obtained by reading the reference surface directly against the reference plane image data on the characteristic memory, the reference plane image data corresponding reference Mende over data read (L '(n)) it is possible to derive The number of operation steps can be reduced.

(5) the characteristics memory on reference Mende data, set their original reference Mende over other one (Rf 0) the reference value and proportional table to ratio data of each reference Mende chromatography data for the reference value (In Table 2, Rf0 / Rf0-Rft / Rf0, Rl0, Rl0 / Rl0-Rlt / Rl0); The image reading apparatus according to any one of (1) to (3) above.

Since the ratio data can be expressed with a smaller number of bits than the original read image data, the required memory capacity of the characteristic memory (221) can be reduced, and data for reading / writing data from / to the characteristic memory (221) It is possible to reduce the number of parallel transfer lines corresponding to the number of data bits.

(6) reference Mende chromatography data of the said characteristic memory is the reference plane image data (Table 1 S (L) -St (L)); any one of the above (1) to (5) The image reading apparatus described.

When setting (storing) data in the characteristic memory in the initial stage, reference plane image data obtained by reading a reference plane temporarily provided, or reference plane image data that has already been acquired and registered separately in an electronic information storage medium the so directly registered as the reference Mende chromatography data (L '(n)), can reduce the number of operation stroke at the time of the data set.

(7) the reference Mende over data on the characteristics memory table the ratio of each reference Mende over data to said reference value one of their original reference Mende over data a (S0 (L)) and the reference value Ratio data (S0 (L), S0 (L) / S (L) -St (L) / S0 (L) in Table 2); described in any one of (1) to (5) above Image reading apparatus.

Since the ratio data can be expressed with a smaller number of bits than the original read image data, the required memory capacity of the characteristic memory (221) can be reduced, and data for reading / writing data from / to the characteristic memory (221) It is possible to reduce the number of parallel transfer lines corresponding to the number of data bits.

(8) the reference data generating means (218) just before the start of reading each document, the correction reference Mende chromatography data (L '(n)) to derive given to the shading correction means; (1 The image reading device according to any one of (7) to (7).

By generating shading correction reference plane data for each original reading and shading correction using the data, even if there is contamination in the optical path from the illumination light source to the image sensor, or the light amount of the illumination light source changes over time, the read output image This reduces the possibility of smudged images and vertical stripes in the image, and also reduces the possibility that a density difference will occur in the output image as the first document becomes the last document in sequential sequential reading of a plurality of documents.

  (9) The image signal processing means (209) includes a variable gain amplifier that amplifies an electrical signal output from the image sensor; the reference data generation means (218) is configured to emit the illumination immediately after an operating voltage is applied. When the light source is turned on, the reference plane is read, the obtained reference plane image data is referred, and the gain of the variable gain amplifier is adjusted to a value that matches the level of the electric signal with a reference value; The image reading apparatus according to any one of 1) to (8).

  The gain adjustment similar to the gain adjustment using the image data for reading the reference surface can be performed in a short time without driving the illumination light source and the optical system.

  (10) The reference plane is a pair (239f, 239l) located in the field of view for generating image data of one line of main scanning for reading the original document and at both ends of the one line of main scanning; The image reading apparatus according to any one of (1) to (9) above.

(11) the reference data generating means (218), the main scanning direction from the reference plane to the reference Mende over data to derive, based on each read reference surface data of the pair of reference surfaces (239f) The image reading apparatus according to (10), wherein an addition value of a weighted value inversely corresponding to the distance is given to the shading correction unit as the correction reference plane data.

Because deriving a pair of reference surfaces of the correction reference Mende over data reflecting the respective read reference Mende chromatography data (L '(n)), it is possible to improve the shading correction accuracy.

(12) the reference data generating means (218), one of the reading of the reference Mende over other reference surface (239f) is dark than the threshold, the reference surface data based on other reference Mende over data (L '(n)) generated by the providing prior Symbol shading correction means as a correction reference Mende over data; image reading apparatus according to (10) or (11).

The stability and reliability of generation of correction reference plane data for shading correction by reading the reference plane is improved.

(13) The reference planes are a pair (239f, 239l) located in a field of view for generating image data of one line of main scanning for reading the original document and at both ends of the one line of main scanning;
The first mode the reference data generating means in (speed priority) (218) may, when the read reference Mende over bright than data threshold in both the reference surfaces (239f), the pair of reference surfaces (239f the sum of weighted values reversed corresponding to the main scanning direction distance from the reference plane to the reference Mende chromatography data (L '(n)) to derive based on each read reference Mende over another) the given to the shading correction means as a correction reference plane data, when reading the reference Mende over data of one of the reference surfaces (239f) it is dark than the threshold value, based on other reference Mende over data reference deriving the surface data (L '(n)) applied to said shading correction unit as the correction reference plane data, the dark or the threshold than the reading of the reference Mende over data threshold in both the reference surface (239f) and equivalent when it is said reference surface the reference Mende over data by reading the (239A) (L '(n )) as the correction reference plane data The image reading apparatus according to (2) above, which is given to a shading correction unit.

Prior to reading of the original of the second mode (image quality priority), gives the shading correction means based Mende over data read reference plane (239A) (L '(n)) as a correction reference plane data, a second mode (Image quality priority) can be selected. Since the second mode produces the actual reference Mende over data read reference plane (239A) (L '(n )), can be expected higher accuracy shading correction. In addition, when any reading of a pair of reference planes fails in the first mode (speed priority), the correction reference plane data is generated in the second mode (image quality priority), although the speed is sacrificed. Further, the stability and reliability of generation of correction reference plane data for shading correction are improved.

(14) the reference data generating means (218), when reading the reference Mende over data of both the reference surfaces (239f) is a dark or a threshold value equivalent to than the threshold value, notifies the abnormality; (10 The image reading device according to any one of (13) to (13).

(15) The image reading device (210, 230) according to any one of (1) to (14) above;
An image data processing device (IPU) that converts image data output by the image reading device into image data for image output representing an image on a two-dimensional plane; and
Image forming means (PTR) for forming an image on a two-dimensional surface using the image data for image output;
An image forming apparatus comprising:

  (16) The image forming apparatus according to (15), wherein the image reading device is a color document scanner; the image forming unit is a color printer;

  (17) The above further comprising means (38, 32a) for receiving document information from the outside through communication; and means (31a, IMAC) for converting the document information into image data and supplying the image data to the image data processing device (15) The image forming apparatus according to (16).

  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 multi-function full color digital copying machine equipped with an image forming apparatus according to a first embodiment of the present invention. This full-color copying machine is roughly constituted by units of an automatic document feeder (ADF) 230, an operation board OAB, a color scanner 210, a color printer PTR and a finisher 100. The color scanner 210 and the finisher 100 with the operation boards OAB and ADF 230 are units that can be separated from the printer PTR. The color scanner 210 has a control board having a power device driver, sensor inputs, and a controller. Communication with the data processing device ACP (FIG. 5) is performed, and the timing is controlled to read the document image. The personal computer PC is connected to the image data processing apparatus ACP (FIG. 5) of the copying machine via a LAN (Local Area Network). An exchange PBX connected to a telephone line PN (facsimile communication line) is connected to the facsimile control unit FCU (FIG. 5). The printed paper of the color printer PTR is discharged to the finisher 100.

  FIG. 2 shows the mechanism of the color printer PTR. The color printer PTR of this embodiment is a laser printer. An assembly (image forming unit) of a photosensitive member 15 and a developing device 27 and a charger, a cleaning device, and a transfer device (illustration unit) (not shown) that forms a one-color toner image is Bk (black), C (cyan), M ( There are four sets in total, one for each image formation of magenta) and Y (yellow), arranged in tandem along the conveyor belt 16, and each color toner image formed by them is sequentially one sheet. Are transferred onto the transfer paper.

  The transfer sheets stacked on the first tray 8, the second tray 9, and the third tray 10 are fed by the first paper feeding device 11, the second paper feeding device 12, and the third paper feeding device 13, respectively, and are conveyed vertically. The unit 14 is transported to a position where it abuts on the photoreceptor 15. Image data read by the scanner 50 is written onto the uniformly charged photoreceptor 15 by a charger (not shown) by laser exposure from the writing unit 60, thereby forming an electrostatic latent image. As the electrostatic latent image passes through the developing unit 27, a toner image appears on the photoreceptor 15. The toner image on the photoconductor 15 is transferred while the transfer paper is conveyed by the conveyance belt 16 at the same speed as the rotation of the photoconductor 15. Thereafter, the image is fixed by the fixing unit 17 and discharged to the finisher 100 of the post-processing apparatus by the paper discharge unit 18.

  The finisher 100 of the post-processing apparatus shown in FIG. 2 can guide the transfer paper conveyed by the paper discharge unit 18 of the main body in the normal paper discharge roller 103 direction and the staple processing unit direction. By switching the switching plate 101 upward, the sheet can be discharged to the normal discharge tray 104 side via the transport roller 103. Further, by switching the switching plate 101 downward, the switching plate 101 can be conveyed to the staple table 108 via the conveying rollers 105 and 107. The transfer paper loaded on the staple table 108 is aligned by the paper aligning jogger 109 each time it is discharged, and is bound by the stapler 106 upon completion of partial copying. The group of transfer sheets bound by the stapler 106 is stored in the staple completion discharge tray 110 by its own weight.

  On the other hand, the normal paper discharge tray 104 is a paper discharge tray that can move back and forth (in a direction perpendicular to the paper surface of FIG. 2). The paper discharge tray section 104 that can be moved back and forth moves forward and backward for each original or each copy section sorted by the image memory, and sorts copy paper that is simply discharged.

  When images are formed on both sides of the transfer paper, the transfer paper fed from each of the paper feed trays 8 to 10 is not guided to the discharge tray 104 side, and the branch claw 19 for switching the path is provided. By turning it downward, it is once guided to the reversing unit 112 and then stocked in the duplex feeding unit 111.

  Thereafter, the transfer paper stocked on the double-sided paper feeding unit 111 is re-fed from the double-sided paper feeding unit 111 to transfer the toner image formed on the photosensitive member 15 again, and the branching claw 112 for switching the path. Is returned to the horizontal in the figure and guided to the paper discharge tray 104. In this way, when creating images on both sides of the transfer paper, the reversing unit 112 and the duplex feeding unit 111 are used.

  The photoreceptor 15, the conveyance belt 16, the fixing unit 17, the paper discharge unit 18, and the development unit 27 are driven by a main motor (not shown), and each of the paper feeding devices 11 to 13 does not drive the main motor. It is driven by being transmitted by each sheet feeding clutch. The vertical conveyance unit 14 is driven by transmitting the drive of the main motor by an intermediate clutch (not shown).

  FIG. 3 shows a document image reading mechanism of the scanner 210 and the ADF 230 attached thereto. The document placed on the contact glass 231 of the scanner 210 is illuminated by the illumination lamp 232, and the reflected light (image light) of the document is reflected by the first mirror 233 in parallel with the sub-scanning direction y. The illumination lamp 232 and the first mirror 233 are mounted on a first carriage that is driven at a constant speed in the sub-scanning direction that is the direction from left to right in FIG. Second and third mirrors 234 and 235 are mounted on the second carriage, which is driven in the same direction as the first carriage, and the image light reflected by the first mirror 233 is second. The light is reflected downward (z) by the mirror 234 and reflected in the sub-scanning direction y by the third mirror 235, converged by the lens 236, irradiated onto the CCD 207, and converted into an electrical signal. The first and second carriages are driven in the y direction forward (original scanning) and backward (return) using the electric motor 238 as a drive source. As described above, the scanner 210 is a flatbed type original scanner that scans the original on the contact glass 231 with the lamp 232 and the mirror 233 and projects the original image on the CCD 207. A glass 240 serving as a sheet-through reading window is located at a reading visual field position of the first mirror 233 when one carriage is stopped at a home position (standby position) HP, and an automatic document feeder (ADF) is disposed above the glass 240. ) 230 is mounted, and the transport drum (platen) 244 of the ADF 230 faces the glass 240.

  The documents stacked on the document tray 241 of the ADF 230 are fed between the conveyance drum 244 and the pressing roller 245 by the pickup roller 242 and the registration roller pair 243, and are in close contact with the conveyance drum 244 and pass over the reading glass 240. Then, the paper is discharged onto a paper discharge tray 248 serving as a pressure plate below the document tray 241 by the paper discharge rollers 246 and 247. This transport system is driven by an electric motor 224. Near the reading glass 240, there is a base point sensor (home position sensor HPS) 249 that detects the first carriage.

  When the image on the surface of the document passes through the reading glass 240 serving as a document reading window, the image is irradiated by the illumination lamp 232 that is moving immediately below the image, and the reflected light on the surface of the document is optical below the first mirror 233. The CCD 207 is irradiated through the system and subjected to photoelectric conversion. That is, it is converted into RGB color image signals.

  The base body 248 of the ADF 230 is hinge-coupled (hinge-connected) to the base body of the scanner 210 on the back side (the back side of the paper surface in FIG. 3), and has a handle 250m on the near side of the base body 248 (the front side of the paper surface in FIG. 3). By pulling up the base 248, the ADF 230 can be raised to a standing posture that forms approximately 60 degrees on the contact glass 231. On the back side of the base body 248 of the ADF 230, the base level 248 of the ADF 230 is high level H (“1”) indicating “open” with a wide opening of about 20 degrees or more with respect to the contact glass 231 and smaller than about 20 degrees. There is a pressure plate opening degree detection switch 252 that generates a low level L (“0”) signal indicating “closed” by the opening degree. When the pressure plate 250p of the ADF 230 facing the contact glass 231 is attached to the bottom surface portion of the ADF 230 and the opening degree of the ADF 230 is 0 degree, the lower surface of the pressure plate 250p is the upper surface of the contact glass 231 as shown in FIG. Close contact with.

  When the opening degree detection signal of the pressure plate opening degree detection switch 252 is H indicating “open” and the ADF 230 is opened to about 60 degrees, the lamp 232 is temporarily located below the contact glass 231 and visible to the user. When lit, the light enters the user's eyes. However, when the opening degree detection signal of the pressure plate opening degree detection switch 252 is L indicating “closed” and the opening of the ADF 230 is about 20 degrees or less, the lamp 232 is temporarily located under the contact glass 231 and visible from the outside. Even if it is turned on, the light is blocked by the pressure plate 250p and hardly enters the eyes of the user.

In FIG. 4, the upper surface of the top plate equipped with the contact glass 231 is shown. Reference surfaces 239f and 239l that are white surfaces are arranged outside the glass 240 and in the reading field of the CCD 207 in the main scanning direction x at the position y in the sub scanning direction of the reading glass 240 that is a sheet-through reading window. 1 shows the system configuration of the image processing system of the copying machine shown in FIG. In this system, a color document scanner 210 including a reading unit 211 and an image data output I / F (Interface) 212 is connected to an image data interface control CDIC (hereinafter simply referred to as CDIC) of the image data processing apparatus ACP. Yes. A color printer PTR is also connected to the image data processing apparatus ACP. The color printer PTR receives YMCK recording image data from the image data processor IPU (Image Processing Unit; hereinafter simply referred to as IPU) of the image data processing apparatus ACP to the writing I / F 134 and prints it out at the image forming unit 135. To do. The image forming unit 135 is shown in FIG.

  The image data processing apparatus ACP (FIG. 5) is connected to a router, and a LAN hub (not shown) connected to the personal computer PC and a modem (not shown) connected to the Internet are connected to the router. The image data processing apparatus ACP can send and receive image data by communicating with devices connected to the LAN (for example, a personal computer PC, a server DSR, a printer, a scanner, a multi-function copying machine, etc.). In addition, image data can be transmitted and received by communicating with other devices having an Internet communication function via the Internet. The distribution server DSR connected to the LAN hub is a computer that distributes a file (mail, image) transmitted or stored therein to a designated or registered destination (LAN connection device or Internet connection device). is there.

  The image data processing device ACP (hereinafter simply referred to as ACP) includes a parallel bus Pb, an image memory access control IMAC (hereinafter simply referred to as IMAC), an image memory MEM (memory module; hereinafter simply referred to as MEM), and a hard disk device. An HDD (hereinafter simply referred to as HDD), a system controller 31a, a RAM 34, a nonvolatile memory 35, a font ROM 36, a CDIC, an IPU, and the like are provided. A facsimile control unit FCU (hereinafter simply referred to as FCU) is connected to the parallel bus Pb. The operation board OAB is connected to the system controller 31a.

  The RGB image signal generated by the image sensor of the CCD 207 of the reading unit 211 that optically reads the document of the color document scanner 210 is subjected to signal processing on the sensor board unit SBU, converted into RGB image data, and shading correction, The data is sent to the CDIC via the output I / F 212.

  The CDIC performs data transfer between the output I / F 212, the parallel bus Pb, and the IPU, and communication between the process controller 131 and the system controller 31a that controls the entire ACP. The RAM 132 is used as a work area for the process controller 131, and the nonvolatile memory 133 stores an operation program for the process controller 131. In addition to the semiconductor memory MEM, there is an HDD for storing a lot of image data. By using the HDD, there is a feature that an external power source is unnecessary and an image can be held permanently. Many original images can be read by a scanner and held in the HDD, and many document images provided by the PC can be held.

  The image memory access control IMAC (hereinafter simply referred to as IMAC) is equivalent to the hardware and software of a personal computer. In addition to controlling the writing / reading of image data and control data to / from the MEM and HDD, A web server (software), an FTP server (software), an SMTP server (software), a DHCP server (software), and other files and servers (software) used for sending and receiving mail are set up. These software (programs) are stored in the HDD.

  The system controller 31a controls the operation of each component connected to the parallel bus Pb. The RAM 34 is used as a work area for the system controller 31a, and the nonvolatile memory 35 stores an operation program for the system controller 31a.

  The operation board OAB inputs processing to be performed by the ACP. For example, the type of processing (copying, facsimile transmission, image reading, printing, etc.), the number of processings, etc. are input. Thereby, the image data control information can be input.

  The RGB image data read by the scanner 210 and the CCD 207 of the ADF is subjected to image processing for correcting reading distortion such as scanner gamma correction and filter processing by the IPU, and then stored in the MEM. When printing out MEM image data, the IPU performs color conversion of RGB signals to YMCK signals, and performs image quality processing such as printer gamma conversion, gradation conversion, and gradation processing such as dither processing or error diffusion processing. The image data after the image quality processing is transferred from the IPU to the writing I / F 134. The writing I / F 134 performs laser control on the gradation processed signal by pulse width and power modulation. Thereafter, the image data is sent to the image forming unit 135, and the image forming unit 135 forms a reproduced image on the transfer paper.

  Based on the control of the system controller 31a, the IMAC controls the access of image data, MEM, and HDD, develops data for printing on a personal computer PC (hereinafter simply referred to as PC) connected to the LAN, and effectively uses the MEM and HDD. Secondary compression / decompression of image data for image data, generation of an image file using various servers (software), and transmission and reception via a LAN or the Internet.

  The image data sent to the IMAC is stored in the MEM or HDD after data compression, and the stored image data is read out as necessary. The image data read out for printing is decompressed, returned to primary compressed data, returned from the IMAC to the CDIC via the parallel bus Pb, and primarily decompressed by the CDIC to return to the original image data. After transfer from the CDIC to the IPU, image quality processing is performed and the image is output to the writing I / F 134, and a reproduced image is formed on the transfer paper (paper) in the image forming unit 135. When transmitting via the LAN or the Internet, the secondary compressed data is compressed as it is, or compressed by another compression method having high compatibility with the PC, and sent to the LAN or the Internet via the network I / F 38 and the router. Send it out.

  In the flow of image data, the functions of the digital multi-function peripheral are realized by bus control by the parallel bus Pb and CDIC. The facsimile transmission is performed by performing image processing on the image data read by the scanner 210 and the ADF 230 by the IPU and transferring the image data to the FCU via the CDIC and the parallel bus Pb. The FCU performs data conversion to the communication network and transmits it as facsimile data to the public line PN. Facsimile reception is performed by converting line data from the public line PN into image data by the FCU and transferring it to the IPU via the parallel bus Pb and CDIC. In this case, no special image quality processing is performed, and the image is output from the writing I / F 134 and a reproduced image is formed on the transfer paper in the image forming unit 135.

  In a situation where a plurality of jobs, for example, an image reading function, a copy function, a facsimile transmission / reception function, and a printer output function operate in parallel, the usage rights of the reading unit 211, the image forming unit 135, and the parallel bus Pb are allocated to the system. Control is performed by the controller 31a and the process controller 131. The process controller 131 controls the flow of image data, and the system controller 31a controls the entire system and manages the activation of each resource (job). The function selection of the digital multi-function peripheral is performed on the operation board OAB, and processing contents such as an image reading function, an image data registration function, a copy function, a print function, a facsimile function, a connection transfer function, etc. are selected by the operation board OAB. Set.

  The system controller 31a and the process controller 131 communicate with each other via the parallel bus Pb, CDIC, and serial bus Sb. Specifically, communication between the system controller 31a and the process controller 131 is performed by performing data format conversion for data and interface between the parallel bus Pb and the serial bus Sb in the CDIC.

  Various bus interfaces such as a parallel bus I / F 37, a serial bus I / F 39, a local bus I / F 33AA, and a network I / F 38 are connected to the IMAC. The system controller 31a is connected to related units via a plurality of types of buses in order to maintain independence in the entire ACP.

  The system controller 31a controls other functional units via the parallel bus Pb. The parallel bus Pb is used for transferring image data. The system controller 31a issues to the IMAC an operation control command for storing image data in the MEM and HDD. This operation control command is sent via IMAC, parallel bus I / F 37, and parallel bus Pb. In response to this operation control command, the image data is sent from the CDIC to the IMAC via the parallel bus Pb and the parallel bus I / F 37. The image data is stored in the MEM or HDD under the control of the IMAC. On the other hand, the ACP system controller 31a functions as a printer controller, network control, and serial bus control in the case of a call from the PC as a printer function. In the case of via the network, the IMAC receives print output request data via the network I / F 38. In the case of a general-purpose serial bus connection, the IMAC receives print output request data via the serial bus I / F 39. The general-purpose serial bus I / F 39 corresponds to a plurality of types of standards.

  Print output request data from the PC is developed into image data by the system controller 31a. The development destination is an area in MEM. Font data necessary for expansion is obtained by referring to the font ROM 36a via the local bus I / F 33a and the local bus Rb. The local bus Rb connects the controller 31a to the nonvolatile memory 35a and the RAM 34a. Regarding the serial bus Sb, in addition to the external serial port 32a for connection with the PC, there is also an interface for transfer with the operation board OAB which is an operation unit of the ACP. This is not print development data, but communicates with the system controller 31a via the IMAC, accepts processing procedures, displays the system status, and the like. Data transmission / reception between the system controller 31a and the MEM, HDD, and various buses is performed via the IMAC. Jobs that use MEM and HDD are centrally managed in the entire ACP.

  The CDIC receives image data output from the color document scanner 210 (SBU) and outputs it to the IPU. The IPU performs “scanner image processing” 190 and sends it to the CDIC. The CDIC performs primary compression of image data in order to increase transfer efficiency on the parallel bus Pb. The compressed image data is sent to the parallel bus Pb. Image data input from the parallel data bus Pb is primarily compressed for bus transfer and is expanded by CDIC. The decompressed image data is transferred to the IPU. In the IPU, RGB image data is converted into YMCK image data by “image quality processing”, converted into image data Yp, Mp, Cp, Kp for image output of the printer 100 and output to the color printer 100.

  The CDIC has a conversion function of parallel data transferred by the parallel bus Pb and serial data transferred by the serial bus Sb. The system controller 31a transfers data to the parallel bus Pb, and the process controller 131 transfers data to the serial bus Sb. The CDIC performs parallel / serial data conversion for communication between the two controllers 1 and 131.

  FIG. 6 shows a configuration of an electric system for image reading of the scanner 210 and the ADF 230. The electrical signals output from the image sensor 207, that is, the R, G, B color analog image signals are respectively amplified by the variable gain amplifier 222 and converted into digital image signals, that is, image data by the A / D conversion 219. This image data is smoothed by averaging 216, subjected to shading correction 217, and output to the image data processor IPU via the CDIC. In the A / D conversion 212, the analog image signal is digitally converted into image data.

  The scanner control circuit 206 controls the lighting timing control circuit 205, the signal processing timing control circuit 213, and the motor control unit 260 in accordance with instructions from the ACP system controller 31a and the process controller 131. The lighting timing control circuit 205 controls on / off of the exposure lamp 232 (232a, 232b) in accordance with an instruction from the scanner control circuit 206, and adjusts the illuminance (light quantity) instructed by the CPU 220 via the signal processing timing control circuit 222. The brightness (time series average value or smooth value) of the exposure lamp 232 is determined. Reference numerals 232a and 232b may be collectively indicated by reference numeral 232.

  The motor control unit 260 controls the sub-scanning drive motor 238 and the ADF motor 224 in accordance with instructions from the scanner control circuit 206. These motors are all stepping motors, and rotary encoders (E) 221 and 225 are connected to the shaft of the drive system. The scanning position (y) and the driving amount of the document, and the front and rear end positions and the feeding amount of the ADF-fed document are grasped by counting the electric pulses generated by the rotary encoders 221 and 225. The paper sensor 223 shown in FIGS. 3 and 6 includes a sensor that detects whether or not a document is on the document tray of the ADF 230, a paper jam detection sensor, and a document size detection sensor. The base point sensor 249 detects the arrival of the reference position (home position HP) of the first carriage.

  The signal processing timing control circuit 222 generates various signals in accordance with instructions or control signals from the scanner control circuit 206, the ACP system controller 31a, the process controller 131, and the CPU (or microcomputer) 220. That is, when image reading is started, control signals including a shift gate signal SH, a transfer clock, a reset signal RS, a clamp gate signal CLP, and the like are given to the image sensor 207, and pixel synchronization is given to the system controller 31a. A clock pulse CLK, a line synchronization signal LSYNC, and a main scanning effective period signal LGATE are output. The pixel synchronization clock pulse CLK is substantially the same signal as the shift clock given to the image sensor 207. The line synchronization signal LSYNC is a signal corresponding to the line synchronization signal MSYNC output from the beam sensor of the image forming unit 135 of the printer 14, but output is prohibited when the image is not read. The main scanning effective period signal LGATE becomes a high level H at a timing at which the image signal output from the image sensor 207 can be regarded as effective (original area reading period).

  Upon receiving a reading start instruction (start) from the ACP system controller 31a, the scanner control circuit 206 switches the control signal Se to the switching regulator 203 to a level instructing to turn on the power supply output, and controls the signal processing timing control circuit 213 (control of the signal processing timing control circuit 213). Signal generation) is controlled to start reading of the image sensor 207, the exposure lamp 232 is turned on, and driving of the sub-scanning drive motor 238 (flatbed reading mode) or ADF motor (sheet through reading mode) is started. Further, the sub-scanning effective period signal FGATE is set to a high level H (outside the document area). This signal FGATE is switched to L indicating the inside of the document area when the first carriage reaches the document start end position in the flat bed reading mode, and the document (leading edge) is sent out from the registration roller in the sheet through reading mode. When the carry amount reaches the feed amount up to the center of the document reading window 240 (home position HP), it is switched to L indicating the inside of the document area. In the flat bed reading mode, when scanning of the document tail ends, in the sheet-through reading mode, when the document tail passes HP, the sub-scanning effective period signal FGATE is returned to H indicating the outside of the document area.

  Commercial alternating current is applied to the alternating current input circuit 201 of the reading unit 11, and the direct current power supply circuit 202 converts the commercial alternating current into direct current. The switching regulator 203 converts the DC voltage into a boosted DC voltage, controls it to a constant voltage, and applies it as a discharge lamp power source to drive circuits 204a and 204b including inverters. In response to the lighting control signals TG1 and TG2 given by the lighting timing control circuit 205, the inverters of the drive circuits 204a and 204b convert the high voltage direct current into the high voltage alternating current during the low level L that is the lighting instruction. Applied to the exposure lamps 232a and 232b. The exposure lamps 232a and 232b are discharge lamps that are driven by the high voltage alternating current to emit light and illuminate the original. The high level H of the lighting control signals TG1 and TG2 is a turn-off instruction. When the lighting control signals TG1 and TG2 are switched to the high level H, the inverters of the drive circuits 204a and 204b are switched to high-voltage direct current and high-voltage alternating current. That is, the high-voltage AC output to the exposure lamp is stopped, and the exposure lamps 232a and 232b are turned off.

  In FIG. 6, the output from the CCD 207 shows only one system consisting of a set of R, G, and B outputs. However, some high-speed CCDs have two or four outputs. is there. Even in such a CCD, by applying the circuit shown in this embodiment to each output, it can be implemented regardless of the number of systems.

  When the document is read, a CCD output signal is output from the CCD 207 to the analog signal processing circuit 209 in synchronization with the CCD drive clock output from the timing control circuit 222. The CCD output signal undergoes signal processing such as sample hold by the sample hold circuit 210, signal amplification by the variable gain amplifier 211, and digital conversion by the A / D converter 212 in the analog signal processing circuit 209, and an averaging circuit. Smoothing is performed at 216 and input to the shading correction circuit 217 as image data (digital data).

  When the shading correction circuit 217 receives the reference plane image data L ′ (n), which is correction reference data corresponding to one line of image data read from the reference white board, from the reference value generation circuit 218, the shading correction circuit 217 reads the reference plane image data. A calculation coefficient for making the distribution on one line uniform is calculated for each pixel on the one line and written as correction reference data in a data memory (RAM) inside the shading correction circuit 217. The shading correction data in the data memory is used for normalizing the original image data for reading the original, and corrects the unevenness of the light amount distribution and the unevenness of the sensitivity of the CCD 207. In this embodiment, the original image data of each pixel of each line is multiplied by shading correction data (calculation coefficient) at the same main scanning position (pixel position) on one line, and the product is output as read image data.

  The reference value generation circuit 218 includes a RAM 219 that temporarily stores reference plane image data obtained by reading the reference planes 239f and 239l, a nonvolatile memory 221 that holds stored data even when no power supply voltage is applied, and an analog processing circuit 209. There is a CPU 220 that sets processing characteristics and generates correction reference data for shading correction and supplies it to the shading correction circuit 217.

  A characteristic in which the nonvolatile memory 221 stores a gain that is given as a base point gain (gain at the start of adjustment) to the variable gain amplifier 211, and reference plane image data that is reference plane illuminance data and reference plane image data that is reference plane illuminance data. It is memory. Prior to reading the document, the CPU 220 reads the reference plane to generate reference plane illuminance data, refers to the data in the characteristic memory, and derives reference plane image data corresponding to the generated reference plane illuminance data. A reference data generation unit that supplies the shading correction unit as correction reference data;

  In this embodiment, immediately after the manufacture of the document scanner (210, 230) and immediately after replacement of at least one of the illumination light sources 232a and 232b, the operator performs a reference surface of a white surface (for example, a reference white plate, which will be described later with reference to FIG. 11). A corresponding reference surface 239A) covers the entire surface of the contact glass 240 for sheet-through reading, and instructs “reference value setting”. In response to the reference value setting instruction, the CPU 220 executes a “reference value setting mode”. That is, the first carriage is positioned at HP via the scanner control circuit 206, the lamps 232a and 232b are turned on, the gain data is read from the nonvolatile memory 221, and the gain of the variable gain amplifier 211 is set to a value represented by the gain data. Then, at a predetermined timing T0, T1, T2,... Tt, the reference surfaces 239f and 239l and the covering reference surface are read and written into the RAM 219. Table 1 (a) shows the read data. These read data are written in the nonvolatile memory 221 in association with those read at the same timing. Data to be written in the nonvolatile memory 221 is shown in (b) of Table 1. Each of the reference plane image data L (n) = S0 (L) to St (L) is image data for one line in the main scanning direction x. The reading timing T0 to Tt (time) is until 10 minutes after the lamp is lit, when the lamp illuminance is stabilized, and the interval between the reading timings T0 to Tt is short and constant for a certain period of time because the decrease in illuminance of the lamp is large immediately after lighting. After that, the decrease in illuminance is small and long.

  Instead of executing the above-mentioned “reference value setting mode” for each original scanner or copying machine, the data obtained as described above ((b) in Table 1) is stored in an electronic information storage medium. Each document scanner or copier has a mode in which data is set by transferring and storing data from the electronic information storage medium to the nonvolatile memory 221.

  FIG. 7 shows an outline of a power supply device that supplies power to the color document scanner 210 and the ADF 230. The power supply system is roughly classified into two types, one is an operation power supply circuit 136 that outputs the operation voltage + 5V of the control system and the operation voltage + 24V of the mechanism drive system necessary for the image processing operation, and the other is the main power switch turned on. This is a standby power supply circuit 137 that outputs an operating voltage + 5VE to a standby circuit (access detection circuit) that detects user access in the energy saving mode as long as it is in the state. In response to the power on / off instruction signal from the system controller 31a, the operating power circuit 136 turns on the operating voltage generation circuit (operation mode) when there is a power on instruction, and the operating voltage when there is a power off instruction. There is an energy saving switch circuit that turns off the generator circuit (energy saving mode). The standby power supply circuit 137 supplies power to the pressure plate opening degree detection switch 252, the document sensor 223, the power supply SW (switch) 220 ps in the operation board OAB, the scanner control circuit 220, and the like.

  When the condition for shifting to the energy saving mode is satisfied, the system controller 31a turns off the energy saving switch circuit inside the operation power supply circuit 136 using the signal Poff. That is, the mode shifts to the energy saving mode. If the pressure plate opening degree detection circuit 252, the paper sensor 223, and the power supply switch 220Ps provide the scanner control circuit 206 with a state change signal indicating that there is a user access when the mode is shifted to the energy saving mode, the scanner control circuit 206 The energy saving switch circuit inside the operation power supply circuit 136 is turned on using the signal Son. That is, the operation mode is entered.

  In the present embodiment, the power supply circuits 136 and 137 apply an operating voltage to required portions of the copying machine shown in FIG. 1, and thus the system controller 31a turns on / off the energy saving switch circuit of the operating power supply circuit 136. To control. However, in the embodiment in which the color document scanner 210 is a single product, the system controller 31a shown in FIG. 7 is not provided, and the scanner control circuit 206 controls on / off of the energy saving switch circuit of the operation power supply circuit 136, and the scanner control circuit 206 However, the image reading control excluding the portion related to printing and copying in the image processing control (FIG. 8) described below is executed.

  FIG. 8 shows an outline of image processing control performed jointly by the system controller 31a and the process controller 131 shown in FIG. 5 and the scanner control circuit 206 and the CPU 220 shown in FIG.

  Please refer to FIG. The operation voltage (+ 5VE, + 5V, + 24V) is changed by turning on (turning on) a main power switch (not shown) or by turning on the energy saving switch circuit of the operation power supply circuit 136 for returning from the energy saving mode to the operation mode. The system controller 31a initializes the copying system (FIG. 5) (step 1), the scanner control circuit 206 of the color document scanner 210 performs carriage homing (step 2), and the system controller 31a A timer Td1 for measuring the waiting time Td1 without access is started (3).

  After the timer Td1 is started, the system controller 31a waits for user input (including a command from the PC) in "input reading" (4), and when there is no user input and the timer Td1 times out (13), the energy saving mode (14) and wait for user access (15). When there is a user access, the scanner control circuit 206 turns on the energy saving switch circuit of the operation power supply circuit 136 using the signal Son. As a result, the operation power supply circuit 136 generates and outputs the image processing operation voltages + 5V and + 24V, whereby the system controller 31a and the scanner control circuit 206 return to “initial setting” (1).

  In “input reading” (4), the system controller 31a waits for an image processing instruction input from the operation board OAB or the personal computer PC. When the power supply SW that is a momentary input key switch of the operation board OAB is turned on, the system controller 31a is currently in the “operation mode”, and the power supply SW in this mode is turned on to “energy saving mode”. Since this is a transition instruction, the mode shifts to the energy saving mode. Since turning on the power supply SW in the “energy saving mode” is an instruction to return or shift from the “energy saving mode” to the “operation mode”, the energy saving switch circuit of the operation power supply circuit 136 is turned on. That is, the operation mode is restored.

  When there is an original reading instruction in “input reading” (4), the system controller 31a instructs the scanner control circuit 206 to read the original, and in response to this, the scanner control circuit 206 turns on the lamps 232a and 232b and notifies the CPU 220. Instructs generation of a reference value. The scanner control circuit 206 and the CPU 220 read the original (7, 10). When there is a print instruction, the system controller 31a instructs the process controller 131 to print, and the process controller 131 controls printing by the color printer PTR (8, 11). When there is a copy instruction, the system controller 31a instructs the process controller 131 to copy, and the process controller 131 instructs the color original scanner 210 to read an image and controls printing by the printer PTR (9, 12). Each time these image processes are completed, the system controller 31a restarts the timer Td1 (3).

  When the condition for shifting to the “energy saving mode” is satisfied, the system controller 31a turns off the energy saving switch circuit of the operation power supply circuit 136 (14).

  While in the energy saving mode, the scanner control circuit 206 waits for user access (15). When there is a user access, the scanner control circuit 206 turns on the energy saving switch circuit of the operation power supply circuit 136 using the signal Son. As a result, the operation power supply circuit 136 generates and outputs the image processing operation voltages + 5V and + 24V, whereby the system controller 31a and the scanner control circuit 206 return to “initial setting” (1).

  FIG. 9 shows an outline of document reading control by the scanner control circuit 206 and the CPU 22. This is for "reading" (10) in FIG. 8, but is similarly executed in original reading for obtaining original image data in "copy" (12) in FIG.

  Please refer to FIG. In response to the document reading instruction (or copying instruction), the scanner control circuit 206 turns on the lamps 232a and 232b (21), and then the CPU 220 gains the gain from the nonvolatile memory 221 at the time when the rising transition period of the lamp light quantity has elapsed. Data is read, and the gain represented by the data is set in the variable gain amplifier 211. At this time, the first carriage is at the home position HP. Then, the reference surfaces 239f and 239l are read, the average value (may be a peak value) of the image data of the reference surfaces 239f and 239l is obtained, and the gain of the variable gain amplifier 211 is adjusted so that it becomes the reference value. The gain at the reference value is updated and registered in the nonvolatile memory 221 (22).

  After the gain adjustment is completed, prior to reading each document, the first carriage is placed at the home position HP and the reference surfaces 239f and 239l are read (23). When it is higher than the threshold (on the white side), in the “illuminance reduction ratio calculation 1” (25), the two adjacent reference surface image data Rfm (high side) between which the read image data Rf of the reference surface 239f is located. , Rfm + 1 (low side) are read, and difference values Rfm-Rf and Rfm-Rfm + 1 between Rfm and Rfm are calculated. The correlation of these data is shown at the beginning of Equation 1. Similarly, difference values Rlm−Rl and Rlm−Rlm + 1 are calculated with respect to the reading value of the reference surface 239l.

In “reference value generation 1” (26), reference surface image data Lfm (n) and Lfm + 1 associated with the reference surface image data Rfm (high side) and Rfm + 1 (low side) on the nonvolatile memory 221 are displayed. (N) is read out, and the reference plane image data {Lfm corresponding to the image data Rf is obtained by interpolation calculation using the ratio (Rfm−Rf) / (Rfm−Rfm + 1) of the difference values Rfm−Rf and Rf−Rfm + 1 as an interpolation ratio. (n) + [(Rfm−Rf) / (Rfm−Rfm + 1)] × [Lfm (n) −Lfm + 1 (n)]}
Is calculated.

Similarly, the reference plane image data Llm (n) and Llm + 1 (n) associated with the reference plane image data Rlm (high side) and Rlm + 1 (low side) on the nonvolatile memory 221 are read and the difference is read. Reference plane image data {Llm (n) + [(Rlm-Rl) / ((Rlm-Rl) / (Rlm-Rl) / (Rlm-Rl) / (Rlm-Rl) / (Rlm-Rl) / (Rlm-Rl) / (Rlm-Rl) / (Rlm-Rl) / (Rlm-Rl) / (Rlm-Rl) / Rlm−Rlm + 1)] × [Llm (n) −Llm + 1 (n)]}
Is calculated.

  Then, the reference plane image data L ′ (n) at the n position (pixel of x = n) on one line of 7016 pixels is represented by weight values (7016-n) / 7016 and n / 7016 by the n position on one line. The weighting calculation used is calculated as shown in Equation (p3) of Equation 1, and this is used as correction reference data.

As a result of reading the reference surfaces 239f and 239l (23), the reading level of the reference surface 239f is higher than the predetermined white threshold (on the white side), but the reading level of the reference surface 239l is below the predetermined white threshold (black side). In this case, since the reliability of the correction reference data generated based on the reading level of the reference surface 239l is expected to be low, the reference surface image data {Lfm (n) + [(Rfm−Rf) / (Rfm−Rfm + 1)] × [Lfm (n) −Lfm + 1 (n)]}
Is calculated as shown in the equation (p4) of Equation 1 and used as correction reference data (31-33). When the reading level of the reference surface 239l is higher than the predetermined white threshold (on the white side), but the reading level of the reference surface 239f is equal to or lower than the predetermined white threshold (black side), the reference surface image data corresponding to the image data Rl. {Llm (n) + [(Rlm−Rl) / (Rlm−Rlm + 1)] × [Llm (n) −Llm + 1 (n)]}
Is calculated as shown in Equation (p5) of Equation 1 and used as correction reference data (31-33).

  When the result of reading the reference surfaces 239f and 239l (23) and the reading levels of the reference surfaces 239f and 239l are both equal to or less than the white threshold (black side), the illumination abnormality is displayed on the display of the operation board OAB (34), and the lamp The lights 232a and 232b are turned off (35).

  When the reference value generation is successful, the generated correction reference data L ′ (n) is given to the shading correction circuit 217. When the shading correction circuit 217 receives the correction reference data L ′ (n) from the reference value generation circuit 218, the shading correction circuit 217 makes the distribution on the one line of the reference plane image data L ′ (n), which is the correction reference data, uniform. The calculation coefficient is calculated for each pixel on the one line and written as shading correction data in a data memory (RAM) inside the shading correction circuit 217 (27).

  When the CPU 220 finishes setting the shading correction data as described above, the scanner control circuit 206 drives the carriage in the sub-scanning direction y and reads the image of the original on the glass 231 in the case of flatbed reading (28). . In the case of sheet-through reading, the carriage stays at the home position, and the original feed system of the ADF 230 is driven to read the original (28). In any form of document reading, the shading correction circuit 217 corrects document image data using shading correction data (in this embodiment, a calculation coefficient) in a data memory (RAM) inside the circuit (multiply the calculation coefficient). To do). The data after shading correction is transmitted to the subsequent image processing circuit IPU.

  In the present embodiment, when color reading is performed, fluctuations in the amount of light are different for each RGB, so that the gain adjustment and correction reference data are generated for each RGB, and shading correction is performed for each RGB individually. Of course, the data stored in the non-volatile memory 221 is for three RGB channels. Even in a color image reading apparatus, the gain adjustment and the generation of correction reference data are performed only in the G (Green) channel that can be used as monochrome image data among the RGB three channels during monochrome reading.

  In the case of sheet-through reading of a group of a plurality of originals, the processing from steps 23 to 28 shown in FIG. 9 is performed for each original. As a result, when the flat bed is read, the conventional reference white plate (239A on FIG. 13) is eliminated, so that the sub-scanning distance from the start of reading to the original can be shortened, and the reading time can be shortened. This saves space by the amount of the standard white board.

  Further, at the time of sheet-through reading of a group of a plurality of documents, the reference planes 239f and 239l are read every time between sheets, and correction standard data calculation is performed to form reference white plate data L ′ (n). The reference plane reading operation at the start of sheet-through reading and between papers can be omitted, and the influence of dust mixed in between papers is eliminated, improving the productivity of document reading while ensuring image quality Can be achieved.

  Further, the reference value setting mode in which the entire surface of the contact glass 240 for sheet-through reading is covered with a white reference surface, the reference surface and the reference surface are read, and read data is set in the nonvolatile memory 221 is as follows. This is also performed on the spot when the correction reference data L ′ (x) must be acquired again, such as when the user replaces the lamp, at the time of shipment.

  The hardware of the second embodiment is the same as that of the first embodiment described above, but the data stored in the nonvolatile memory 221 of the second embodiment and the “illuminance reduction ratio calculation” (corresponding to steps 25 and 32 in FIG. 9) and “ The content of “reference value generation” (corresponding to steps 26 and 33 in FIG. 9) is different from that of the first embodiment. The outline of “reading” is expressed in the same manner as in the first embodiment shown in FIG.

  Also in the second embodiment, immediately after the manuscript scanner (210, 230) is manufactured and immediately after replacement of at least one of the illumination light sources 232a and 232b, the operator can obtain a white reference surface (e.g., equivalent to a reference white plate shown in FIG. 11). The entire surface of the sheet-through reading contact glass 240 is covered with the reference surface 239A), and “reference value setting” is instructed. In response to the reference value setting instruction, the CPU 220 executes a “reference value setting mode”. That is, the first carriage is positioned at HP via the scanner control circuit 206, the lamps 232a and 232b are turned on, the gain data is read from the nonvolatile memory 221, and the gain of the variable gain amplifier 211 is set to a value represented by the gain data. Then, at a predetermined timing T0, T1, T2,... Tt, the reference surfaces 239f and 239l and the covering reference surface are read and written into the RAM 219. The ratio of the read value at each timing (T0 to Tt) with respect to the read value of the base point (start point) T0 as the reference timing, that is, the illuminance ratios Rf0 / Rf0 to Rft / Rf0 and S0 (L) / S0 (L) to St (L) / S0 (L) is calculated. Table 2 (a) shows the read data and the calculated illuminance ratio. These read and calculated data are written in the nonvolatile memory 221 in association with those read at the same timing. Data to be written in the nonvolatile memory 221 is shown in (b) of Table 2. Each of the reference plane image data L (n) = S0 (L) to St (L) is reference plane image data for one line in the main scanning direction x. The reading timing T0 to Tt (time) is until 10 minutes after the lamp is lit, when the lamp illuminance is stabilized, and the interval between the reading timings T0 to Tt is short and constant for a certain period of time because the decrease in illuminance of the lamp is large immediately after lighting. After that, the decrease in illuminance is small and long.

  Instead of executing the above-described reference value setting mode for each original scanner or copier, the data obtained as described above ((b) in Table 2) is stored in the electronic information storage medium, and the original is set. There is also an aspect in which data is set for each scanner or copier by transferring and storing data from the electronic information storage medium to the nonvolatile memory 221.

  In the second embodiment, the data stored in the non-volatile memory 221 is an illuminance ratio other than the read values Rf0, Rl0 and S0 (L) of the base point (start point) T0, as shown in Table 2 (b). Therefore, the number of bits representing the illuminance ratio data can be significantly reduced, and the required capacity of the nonvolatile memory 221 can be significantly reduced. That is, a small-capacity nonvolatile memory 221 can be used. In addition, the number of parallel data lines corresponding to the number of data bits in the data transfer line for reading / writing data from / to the nonvolatile memory 221 can be reduced.

  Also in the second embodiment, the scanner control circuit 206 turns on the lamps 232a and 232b in response to an original reading instruction (or a copying instruction) (21), and then the CPU 220 at the time when the rising transition period of the lamp light quantity has passed. The gain data is read from the nonvolatile memory 221 and the gain represented by the gain data is set in the variable gain amplifier 211. At this time, the first carriage is at the home position HP. Then, the reference surfaces 239f and 239l are read, the average value (may be a peak value) of the image data of the reference surfaces 239f and 239l is obtained, and the gain of the variable gain amplifier 211 is adjusted so that it becomes the reference value. The gain at the reference value is updated and registered in the nonvolatile memory 221 (22).

  After the gain adjustment is completed, prior to reading each document, the first carriage is placed at the home position HP and the reference surfaces 239f and 239l are read (23). If it is higher than the threshold (on the white side), the ratio Cf = Rf / of the read image data Rf of the reference surface 239f to the data Rf0 on the memory 221 at the base point T0 in “illuminance reduction ratio calculation 1” (25). Rf0 is calculated, and two adjacent reference plane illuminance ratios Cfm = Rfm / Rf0 (high side) and Cfm + 1 = Rfm + 1 / Rf0 (low side) with the Cf in between are read from the memory 221. The interpolation ratio Cf (n) is calculated as shown in Equation 2 above. Next, in “reference value generation 1” (26), the reference surface reading illuminance ratios Sm (L) / S0 (L) and Sm + 1 (L) / S0 corresponding to the reference surface illuminance ratios Cfm and Cfm + 1. (L) and the reference plane read value S0 (L) are read from the memory 221 to reproduce the reference plane image data Sm (L) and Sm + 1 (L) at the reference plane illumination ratios Cfm and Cfm + 1 2, correction standard data L′ f (n) based on the read level of the front end side reference surface 239f is calculated by an interpolation operation using the interpolation ratio Cf (n) shown by the equation (1).

  Similarly, correction standard data L′ l (n) based on the reading level of the rear end side reference surface 239l is calculated.

  Then, the reference plane image data L ′ (n) at the n position (x = n pixel) on one line 7016 pixels is represented by weight values (7016−n) / 7016 and n / 7016 by the n position on one line. The weighting calculation used is calculated as shown in Equation (3) of Formula 2, and this is used as correction reference data.

  As a result of reading the reference surfaces 239f and 239l (23), the reading level of the reference surface 239f is higher than the predetermined white threshold (on the white side), but the reading level of the reference surface 239l is below the predetermined white threshold (black side). In this case, since the reliability of the correction standard data generated based on the reading level of the reference surface 239l is expected to be low, the correction standard data L ′ (n) is calculated by equation (1) above The correction reference data L′ f (n) is based on the reading level of the front end side reference surface 239f. When the reading level of the reference surface 239f is equal to or lower than the white threshold value and the reading level of the reference surface 239l exceeds the white threshold value, the correction reference data L ′ (n) is calculated by the equation (2) in Equation 2, The correction reference data L′ l (n) is based on the reading level of the end reference surface 239l.

  When the result of reading the reference surfaces 239f and 239l (23) and the reading levels of the reference surfaces 239f and 239l are both below a predetermined white threshold (black side), an illumination abnormality is displayed on the display of the operation board OAB (34). ), The lamps 232a and 232b are turned off (35).

  When the correction reference data is successfully generated, the generated correction reference data L ′ (n) is given to the shading correction circuit 217. When the shading correction circuit 217 receives the correction reference data L ′ (n) from the reference value generation circuit 218, the shading correction circuit 217 makes the distribution on the one line of the reference plane image data L ′ (n), which is the correction reference data, uniform. The calculation coefficient is calculated for each pixel on the one line and written as shading correction data in a data memory (RAM) inside the shading correction circuit 217 (27). Other functions of the second embodiment are the same as those of the first embodiment.

  In the third embodiment, as shown in FIGS. 10 and 11, a reference surface 239A corresponding to a conventional reference white plate is provided near the sheet through reading window 240 in the sub-scanning direction y. By providing the reference surface 239A, it is possible to avoid reading operation stop when the reference surface is abnormal, eliminate jigs required in the initial data acquisition mode, and improve gain adjustment accuracy when the power is turned on or when energy saving is restored.

  FIG. 12 shows an outline of document reading control by the scanner control circuit 206 and the CPU 220 of the third embodiment. This is for "reading" (10) in FIG. 8, but is similarly executed in original reading for obtaining original image data in "copy" (12) in FIG.

  In the third embodiment, the document reading mode can be selected and designated as “speed priority” or “image quality priority” by a user instruction from the operation board OAB or the personal computer PC, and image reading when “speed priority” is specified. The processing flow is the same as in the second embodiment. However, if the result of reading the reference surfaces 239f and 239l (23) and the reading levels of the reference surfaces 239f and 239l are both below a predetermined white threshold (black side), an illumination abnormality is displayed on the display of the operation board OAB. (34) In the third embodiment, the reading operation is not stopped, the carriage is driven directly below the reference surface 239A, the reference surface image data is obtained by reading the reference surface 239A, and this is used as the correction reference data. Then, the sheet is supplied to the shading correction circuit 217, and the carriage is returned to the home position, and sheet-through reading equivalent to the conventional one is performed (31-34-42-27-28). In the case of flatbed reading, the carriage is driven from HP directly below the original on the contact glass 231, the reference surface 239 A is read directly below the reference surface 239 A, and is supplied to the shading correction circuit 217, and the carriage is continuously driven as it is. Thus, the same flat bed reading is performed (31-34-42-27-28).

  When “image quality priority” is designated, the carriage is driven directly below the reference surface 239A, the reference surface image data is acquired by reading the reference surface, and this is supplied to the shading correction circuit 217 as correction reference data, and The carriage is returned to the home position, and the same sheet-through reading as before is performed (41-42-27-28). In the case of flatbed reading, the carriage is driven from HP directly below the original on the contact glass 231, the reference surface 239 A is read directly below the reference surface 239 A, and is supplied to the shading correction circuit 217, and the carriage is continuously driven as it is. Then, the flat bed reading similar to the conventional one is performed (41-42-27-28).

  Since the reference surface 239A is always provided in the third embodiment, the stored data shown in (b) of Table 2 in the nonvolatile memory 221 referred to in the case of “speed priority” is stored by the operator from the operation board OAB or the personal computer PC. By instructing “value setting”, the scanner control circuit 206 and the CPU 220 automatically set. That is, when “reference value setting” is instructed, the scanner control circuit 206 first reads the reference surfaces 239f and 231 at the home position HP, stores the reference surface image data in the RAM 219, and moves the carriage directly below the reference surface 239A. Then, the reference surface 239A is read, and the reference surface image data is stored in the RAM 219 (this is the reading of the base point T0). Then, the carriage is returned to the home position HP, and after waiting for the timing T1, the reference surfaces 239f and 231 and the reference surface 239A are read again. Similarly, the reference surfaces 239f and 231 and the reference surface 239A are read at each of timings T2 to Tt. When this is finished, the CPU 220 calculates the illuminance ratio ((a) of Table 2) based on the data on the RAM 219 and stores the data shown in (b) of Table 2 in the nonvolatile memory 221.

  As described above, since the reference surface 239A is provided in the third embodiment, a separate dedicated jig (the reference surface corresponding to the reference white plate, which the operator closes the sheet-through reading window 240 in the first and second embodiments) is not used. I'll do it. When the power is turned on and energy saving is restored, the carriage is moved directly below the reference plane 239A, the reference plane image data is acquired, and the gain adjustment equivalent to the conventional one is performed, so that the reference planes 239f and 23l are read. Gain adjustment can be performed with higher accuracy than gain adjustment using plane image data. Other configurations and functions of the third embodiment are the same as those of the second embodiment.

1 is a front view of a digital processing copying machine including a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing an enlarged mechanism outline of the printer PTR shown in FIG. 1. FIG. 2 is a longitudinal sectional view showing an enlarged mechanism outline of a scanner 210 and an ADF 230 shown in FIG. 1. FIG. 4 is a plan view of the top plate of the scanner 210 shown in FIG. 3. FIG. 2 is a block diagram showing an image processing system of the digital processing copying machine shown in FIG. 1. It is a block diagram which shows the image reading system of the scanner 210 and ADF which are shown in FIG. FIG. 2 is a block diagram showing a power supply system of the digital processing copying machine shown in FIG. 1. It is a flowchart which shows the outline | summary of system control of the system controller 31a shown in FIG. 7 is a flowchart showing an outline of document image reading control performed by a scanner control circuit 206 and a CPU 220 shown in FIG. 6. It is a longitudinal cross-sectional view which shows the mechanism outline | summary of the scanner 210 of 3rd Example of this invention. It is a top view of the top plate of the scanner 210 shown in FIG. 10 is a flowchart showing an outline of document image reading control performed by a scanner control circuit 206 and a CPU 220 of the third embodiment. It is a block diagram which shows the outline | summary of the document reading mechanism of the conventional flat bed system. It is a block diagram showing an outline of a conventional sheet-through type document reading mechanism.

8: 1st tray 9: 2nd tray 10: 3rd tray 11: 1st paper feeder 12: 2nd paper feeder 13: 3rd paper feeder 14: Vertical conveyance unit 15: Photoconductor 16: Conveyor belt 17 : Fixing unit 18: paper discharge unit 19: branch claw 26: transport motor 27: developing device 100: finisher 101: switching plate 103: paper discharge roller 104: paper discharge tray 105: transport roller 106: stapler 107: transport roller 108: Staple table 109: Jogger 110: Paper discharge tray 111: Duplex paper feeding unit 112: Reversing unit 207: Image sensor 221, 225: Rotary encoder 224: Stepping motor 231: Document table glass 232: Illumination lamp 233: First mirror 234: Second mirror 235: Third mirror 236: Lens 238: Stepping mode 239f: front end side reference surface 239l: rear end side reference surface 239A: reference surface 240: contact glass 241: document tray 242: pickup roller 243: registration roller pair 244: transport drum 245: pressing rollers 246, 247: paper discharge roller 248 : Pressure plate 249 also serving as a discharge tray: Base point sensor 251: Scale 252: Pressure plate opening detection switch

Claims (17)

Sub-scanning means for sub-scanning one of the original and an illumination light source for illuminating the original with respect to the other;
An image sensor that converts the projected light image into an electrical signal, that is, an image signal, and outputs it for each main scanning line;
Optical means for projecting reflected light of the document onto the image sensor;
Image signal processing means for converting an electrical signal output from the image sensor into digital data, that is, image data;
Shading correction means for correcting the image data of the document using shading correction data addressed to each pixel on the main scanning line based on the correction reference plane data ;
A reference plane located in the field of view where the illumination light source, image sensor, optical means and image signal processing means generate image data of one main scanning line for document reading and at the end of the one main scanning line;
Reference surface data that is the reference surface image data or reference surface illuminance data when the original view is covered with a reference surface when reading the original and image data is acquired for each of the illumination light source illuminances having different values And a characteristic memory that stores reference surface data that is each reference surface image data or reference surface illuminance data when each reference surface data is obtained in association with each other ; and
Prior to reading of the document, generates the reference surface data by reading the reference surface, the characteristic data referring to the memory, generated reference Mende over data said deriving a corresponding reference Mende over data correction Reference data generation means for giving to the shading correction means as reference surface data ;
An image reading apparatus comprising: Sub-scanning means for sub-scanning one of the original and an illumination light source for illuminating the original with respect to the other;
An image sensor that converts the projected light image into an electrical signal, that is, an image signal, and outputs it for each main scanning line;
Optical means for projecting reflected light of the document onto the image sensor;
Image signal processing means for converting an electrical signal output from the image sensor into digital data, that is, image data;
Shading correction means for correcting the image data of the document using shading correction data addressed to each pixel on the main scanning line based on the correction reference plane data ;
A reference plane located in the field of view where the illumination light source, image sensor, optical means and image signal processing means generate image data of one main scanning line for document reading and at the end of the one main scanning line;
A reference plane that is located away from the reference plane in the sub-scanning direction and extends in the main scanning direction length of the original reading field;
When the image data of the reference plane and the reference plane is acquired for each of the illumination light source illuminances having different values, the reference plane data that is the plurality of reference plane image data or reference plane illuminance data, and each reference plane data A characteristic memory that stores reference surface data that is each reference surface image data or reference surface illuminance data obtained in association with each other ; and
Prior to reading of the original in the first mode, the reference surface data generated by reading the reference plane, with reference to the data of the characteristics memory, deriving a generated reference Mende over data corresponding reference Mende over data and given to the shading correction unit as the correction reference plane data, prior to reading of the original of the second mode, providing a reference Mende over data reading said reference plane in said shading correction means as the correction reference plane data , Reference data generation means;
An image reading apparatus comprising: The reference data generating means, the characteristic memory and reference Mende chromatography data generated by reading the reference plane, the first and second reference surfaces adjacent a pair of reference surfaces data read said is positioned between the ratio of the difference between the data, the interpolation calculation using the first and second reference Mende chromatography data is associated with each of the first and second reference surface data of the characteristics memory by deriving a reference surface data corresponding to the read reference Mende over data in given to the shading correction unit as the correction reference plane data; image reading apparatus according to claim 1 or 2. See Mende over data on the characteristics memory is a reference plane image data; image reading apparatus according to any one of claims 1 to 3. See Mende over data on the characteristics memory is the ratio of each reference Mende over data to said reference value one of their original reference Mende over data to the reference value in the table to specific data; claim 1 4. The image reading apparatus according to any one of items 1 to 3. Reference Mende over data on the characteristics memory is a reference plane image data; image reading apparatus according to any one of claims 1 to 5. Reference Mende over data on the characteristics memory is the ratio of each reference Mende over data to said reference value as a reference value to one of their original reference Mende over data in Table to ratio data; claim 1 6. The image reading apparatus according to any one of 1 to 5. The reference data generating means, just before the start of reading each original, and derive the reference Mende over data supplied to the shading correction unit as the correction reference plane data; to any one of claims 1 to 7 The image reading apparatus described.   The image signal processing means includes a variable gain amplifier that amplifies an electrical signal output from the image sensor; and the reference data generation means is configured to turn on the illumination light source immediately after an operating voltage is applied. The surface is read, and the gain of the variable gain amplifier is adjusted to a value that matches the level of the electric signal with a reference value by referring to the obtained reference surface image data; The image reading apparatus described.   10. The pair of reference planes are located in a field of view that generates image data for one line of main scanning for reading the original document, and at each of both ends of the one line of main scanning; The image reading apparatus according to one. The reference data generating means, weighted inverse corresponding to the main scanning direction distance from the reference plane to the reference Mende over data to derive, based on each read reference Mende over other reference surface of the pair The image reading apparatus according to claim 10, wherein an addition value of the values is given to the shading correction unit as the correction reference plane data. The reference data generating means, one of the reading of the reference Mende over other reference surface is dark than the threshold, the correction reference Mende chromatography generates the reference surface data based on other reference Mende over data as the data supplied to the shading correction unit; image reading apparatus according to claim 10 or 11. The reference planes are a pair located in a field of view that generates image data of one line of main scanning for reading the original document and at both ends of the one line of main scanning;
The reference data generating means in said first mode, when reading the reference Mende over data of both the reference surfaces of the light than the threshold value, based on the reference Mende over data each read reference surface of the pair the sum of weighted values reversed corresponding to the main scanning direction distance from the reference plane to the reference Mende over data to derive Te, given to the shading correction unit as the correction reference plane data, reading of one of the reference surface when the reference Mende chromatography data is dark than the threshold value, and derives the reference Mende over data based on other reference Mende over data supplied to the shading correction unit as the correction reference plane data, both referring when the read reference Mende over another surface is dark or the threshold equivalent to than the threshold value, gives a reference Mende over data reading said reference plane in said shading correction means as the correction reference plane data; wherein Item 2 Image reading apparatus. The reference data generating means, when reading the reference Mende over data of both the reference plane is dark or threshold value equivalent to than the threshold value, notifies the abnormality; according to any one of claims 10 to 13 Image reading apparatus. The image reading apparatus according to claim 1;
An image data processing device for converting image data output by the image reading device into image data for image output representing an image on a two-dimensional plane; and
Image forming means for forming an image on a two-dimensional surface using the image data for image output;
An image forming apparatus comprising:   The image forming apparatus according to claim 15, wherein the image reading device is a color original scanner; and the image forming unit is a color printer.   The image forming apparatus according to claim 15 or 16, further comprising: means for receiving document information from outside through communication; and means for converting the document information into image data and supplying the image data to the image data processing apparatus.

Images