Image reading device and image forming apparatus

An image reading device includes: a foreign-matter image position detection unit that detects a predetermined foreign-matter image from the image read by a document reading unit when the document conveyed by a document conveying unit comes off from a document reading position and detects a main scanning direction position of the foreign-matter image in the main scanning direction; and a lighting control unit that lights up the light-emitting element group arranged in the main scanning direction and lights up the light-emitting elements within a predetermined range from the main scanning direction position of the foreign-matter image in a light emission mode that is different from a light emission mode of other light-emitting elements when the foreign-matter image is detected by the foreign-matter image position detection unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image reading device of the so-called sheet-through type in which a document image is read from one main surface side of a transparent document glass, while the document that is the object of reading is conveyed so as to move on the other main surface of the document glass, and to an image forming apparatus equipped with the image reading device.

2. Description of the Related Art

In an image forming apparatus such as a copier, in a case where a document image is read with a sheet-through image reading device and the image is printed, a stripe-like image extending along the sub-scanning direction sometimes appears in the image. This stripe-like image is usually a result of contamination caused by adhesion of foreign matter such as dirt, dust, or paper powder from the conveyed document to the glass (document glass) of the image reading device. Because this stripe-like image appears as a black stripe on the white background of recording paper after printing or as a white stripe in the image zone, a document reading device has been suggested in which, as indicated in Japanese Patent No. 3313098, in a case where the stripe-like image is detected, the document reading position of a scanner provided in the image reading device is moved in the sub-scanning direction, the document is read in a position without the dirt or the like, and the user is warned when the scanner position is changed. Further, as described in Japanese Patent Application Laid-open No. 2006-148677, an image reading device has been suggested in which the contaminated portion on the document glass is lighted and displayed in the illumination mechanism of a scanner and the user is asked to clean the document glass.

SUMMARY OF THE INVENTION

The present invention further improves the above-described conventional technology.

Thus, the present invention provides an image reading device including: a document reading unit having an illumination mechanism, which illuminates a document with a group of a plurality of light-emitting elements arranged side by side in a main scanning direction, and reading optically an image of the document illuminated by the illumination mechanism via a document glass that extends in the main scanning direction in a predetermined document reading position; a document conveying unit that conveys the document in a sub-scanning direction of the document reading unit with respect to the document reading position; a foreign-matter image position detection unit that detects a predetermined foreign-matter image from the image read by the document reading unit when the document conveyed by the document conveying unit comes off from the document reading position and detects a main scanning direction position of the foreign-matter image in the main scanning direction; and a lighting control unit that lights up the light-emitting element group arranged in the main scanning direction and lights up the light-emitting elements within a predetermined range from the main scanning direction position of the foreign-matter image in a light emission mode that is different from that of other light-emitting elements when the foreign-matter image is detected by the foreign-matter image position detection unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An image reading device and an image forming apparatus in accordance with the present invention will be described below based on embodiments thereof. In the embodiments below, an example is explained in which the image reading device and image forming apparatus of embodiments of the present invention are implemented as a multi-function peripheral provided with functions of a color copier, a scanner, a facsimile apparatus, and a printer.FIG. 1is a vertical cross-sectional view illustrating schematically the internal configuration of a multi-function peripheral1of one embodiment of the image reading device and image forming apparatus in accordance with the present invention.

The multi-function peripheral1is in general configured by a document reading mechanism200and a device body3. The document reading mechanism200is provided with a document conveying unit21, a scanner unit22, an operation unit5, and the below-described turnover mechanism and control unit61(seeFIG. 3). The document conveying unit21is provided with an ADF (Automatic Document Feeder) and has a document tray211, a pick-up roller212, a conveying drum213, a paper discharge roller214, and a paper discharge tray215. Documents, which are reading objects, are placed on the document tray211. The documents placed on the document tray211are picked up one by one by the pick-up roller212and conveyed successively to the conveying drum213via a gap. The documents that have passed through the conveying drum213are successively discharged by the paper discharge roller214to the paper discharge tray215.

The scanner unit (document reading unit)22optically reads an image of the document and generates image data. The scanner unit22is provided with a platen glass221, a light source (illumination mechanism)222, a first mirror223, a second mirror224, a third mirror225, a first carriage226, a second carriage227, an image-forming lens228, and a CCD (Charge Coupled Device)229. The scanner unit22used a plurality of LED (Light Emitting Diode) that are arranged in the main scanning direction as the light source222, and the light from the document is guided to the CCD229by the first mirror223, second mirror224, third mirror225, first carriage226, second carriage227, and image-forming lens228. The configuration of the light source222is described below.

When the document is to be read without the use of the document conveying unit21, the user manually places the document on the platen glass221. The light source222and first mirror223are supported by the first carriage226, and the second mirror224and third mirror225are supported by the second carriage227.

The document reading system of the document reading mechanism200can be a flat-bed reading mode in which the document placed on the platen glass221is read by the scanner unit22and an ADF reading mode in which the document is picked up by the document conveying unit21(ADF) and the document is read in the conveying process.

In the flat-bed reading mode, the light source222illuminates the document placed on the platen glass221, and the reflected light of one line in the main scanning direction is successively reflected by the first mirror223, second mirror224, and third mirror225and falls on the image-forming lens228. The light that has fallen on the image-forming lens228forms an image on a light-receiving surface of the CCD229. The CCD229is a one-dimensional image sensor and simultaneously processes image data of one line of the document. The first carriage226and second carriage227are configured so that they can move in a direction (sub-scanning direction, direction shown by arrow Y) perpendicular to the main scanning direction, and where the reading of one line is completed, the first carriage226and second carriage227move in the sub-scanning reaction and reading of the next line is performed.

In the ADF pick-up mode, the document conveying unit21picks up one by one with the pick-up roller212the documents that have been placed on the document tray211. In this case, the first carriage226and second carriage227are disposed in a preset reading position P that is below a document reading window (document glass)230that is made from a transparent material such as a glass member. When the document is conveyed by the document conveying unit21and the document passes above the document reading window230that is provided on the path by which the document moves from the conveying drum213to the paper discharge tray215, the light source222illuminates the document, the reflected light of one line in the main scanning direction is successively reflected by the first mirror233, second mirror224, and third mirror225and falls on the image-forming lens228. The light that has fallen on the image-forming lens228forms an image on the light-receiving surface of the CCD229. The document is then conveyed by the document conveying unit21and the next line is read.

The document conveying unit21also has a document turnover mechanism (turnover unit) provided with a switching guide216, a turnover roller217, and a turnover conveying path218. The document turnover mechanism turns over the document that has been read from the front surface (one surface of the document) by the first ADF reading and conveyed again to the document reading window230, thereby enabling the CCD229to read the rear surface (the other surface of the document). The document turnover mechanism operates only when two-side reading is performed and does operate in a case of one-side reading. During one-side reading and after rear-side reading during two-side reading, the switching guide216is switched to the upper side, and the document that has passed the conveying drum213is discharged by the discharge roller214to the discharge tray215. After front-side reading during two-side reading, the switching guide216is switched to the lower side, and the document that has passed the conveying drum213is conveyed by the turnover roller217to the turnover conveying path218. The switching guide216is then switched to the upper side, the turnover roller217is reversed, and the document is again fed to the conveying drum213.

The multi-function peripheral1has the device body3and a stack tray6installed to the left of the device body3. The device body3is provided with a plurality of paper feed cassettes461, a paper feed roller462that draws out recording paper, sheet by sheet, from the paper feed cassette461and conveys the paper to an image forming unit40, and the image forming unit40that forms an image on the recording paper conveyed from the paper feed cassette461. The device body3is also provided with a paper feed tray471and a draw-out roller472that draws out, one by one, the documents that are placed on the paper feed tray471toward the image forming unit40.

The recording unit (image forming unit)40is provided with a neutralizing device421that removes residual charges from the surface of a photosensitive drum43, a charging device422that charges the surface of the photosensitive drum43after the neutralization, an exposure device423that outputs laser light and exposes the surface of the photosensitive drum43on the basis of image data acquired by a scanner unit22and forms an electrostatic latent image on the surface of the photosensitive drum43, development devices44K,44Y,44M,44C that form toner images of various colors, namely, cyan (C), magenta (M), yellow (Y), and black (K) on the photosensitive drum43on the basis of the electrostatic latent image, a transfer drum49that transfers and superimposes the toner images of various colors that have been formed on the photosensitive drum43, a transfer device41that transfers the toner image located on the transfer drum49on paper, and a fixing device45that heats the paper having the toner image transferred thereonto and fixes the toner image to the paper. The toners of different colors, namely, cyan, magenta, yellow, and black, are fed from a toner feed container (toner cartridge) that is not shown in the figure. Further, conveying rollers463and464are provided to convey the recording paper that has passed the image forming unit40to the stack tray6or discharge tray48.

In a case where an image is formed on both sides of the recording paper, the image is formed on one side of the recording paper with the image forming unit40and then the recording paper is nipped by the conveying roller463on the side of the discharge tray48. In this nipped state of the recording paper, the conveying roller463is turned over, the recording paper is switched back, the recording paper is again conveyed to the upstream region of the image forming unit40along the paper conveying path L, an image is formed on the other side by the image forming unit40, and then the recording paper is discharged to the stack tray6or discharge tray48.

A display unit that enables the user to view an operation screen or various messages or an operation unit5that has an operation button for inputting various operation commands is provided at the front of the device body3.FIG. 2is an exemplary front view of the operation unit5. The operation unit5is provided with a display unit51, a touch panel52, a numerical key group53, various operation buttons55to57, and a function selection button58. The display unit51is constituted by a LCD (Liquid Crystal Display) or an ELD (Electronic Luminescent Display) and displays an operation guide screen that indicates paper size selection, magnification selection, concentration selection, and the like to the user. The display unit51is formed integrally with the touch panel52. The touch panel52detects a touch position when the user performs a touch operation and outputs a detection signal indicating the touch position to the below-described control unit61.

The numerical key group53serves, for example, to input the number of documents when a document function of the multi-function peripheral1is actuated and to input a phone number of transmission destination when a facsimile function is actuated. A start button55serves to initiate the document operation or scanner operation, and a stop/clear button56serves to stop the document operation or scanner operation and cancel the inputted operation. A reset button57serves to return the display of the display unit51or various settings to the initial state or standard state. A function selection button58serves for setting a multi-function peripheral function, a printer function, a scanner function, and a facsimile function.

FIG. 3is a block diagram illustrating an electric configuration of the multi-function peripheral1. Components identical to those shown inFIGS. 1 and 2are assigned with identical reference numerals and explanation thereof is herein omitted. The multi-function peripheral1is constituted by the document conveying unit21, scanner unit22, operation unit5, image forming unit40, storage unit67, and control unit61.

The document conveying unit21automatically picks up a document placed on the document tray211when copying or scanning is performed in the aforementioned ADF reading mode and conveys the document to enable the reading thereof with the CCD229.

The operation unit5is used to enable the user to perform operations relating to the copier function, printer function, facsimile function, and scanner function and provides the operation commands (command) of the user to the control unit61. The operation unit5includes the display unit51that has a touch panel or the like and the stack button55or numerical key group53that allow the user to perform a variety of instruction inputs such as a copying execution start command or facsimile transmission start command.

The image forming unit40forms on the recording paper an image based on image data obtained with the CCD229or image data transferred from the personal computer or facsimile device.

The storage unit67stores image data obtained by a reading operation of the scanner unit22or image data processed by the below-described control unit61, or stores in advance a communication destination name in an abbreviated register form or facsimile number when facsimile communication is performed, or an IP address of communication party when the device is used as a network scanner, or sub-scanning direction position information of a light source222where the illumination light is not present with respect to a position at a predetermined distance from the document glass provided in the document reading window230.

An opening-closing detection switch500is provided outside the platen glass221on the upper surface portion of the device body3. This switch detects the open-closed state of the document conveying unit21and outputs the detected state to the control unit61(lighting control unit612).

The control unit61controls the operation of the entire multi-function peripheral1and is constituted by CPU, a RAM, and a ROM. The document conveying unit21, the scanner unit22, the operation unit5, an image processing unit615, and an image forming unit40operate under control by the control unit61. The control unit61executes the processing based on an operation control program stored in the ROM (not shown in the figure) or the aforementioned storage unit67correspondingly to various instruction signals inputted by the user into the operation unit5, performs output of the instruction signals and data transfer to the functional units, and performs unified control of the multi-function peripheral1.

In the multi-function peripheral1of the above-described configuration, in a case where a document conveyed by the document conveying unit21in the ADF mode is read by the document reading mechanism200, where a foreign matter adheres to the document reading window230, an image of the foreign matter is picked up by the same pixel in the scanner unit22at respective imaging timing. As a result, a stripe-like image (line L inFIG. 4; referred to hereinbelow as “foreign-matter image”) that extends in the sub-scanning direction can be formed in a position in the main scanning direction that corresponds to the pixel position of the aforementioned same pixel in the image obtained.

Where such a state is allowed to stay till the reading operation of all the documents of the document stack is completed, the foreign-matter image will be generated in all the images obtained in the reading operation and documents that are undesirable for the user will be produced. The multi-function peripheral1of the present embodiment uses the below-described configuration to resolve this problem.

Thus, in addition to the usual image reading operation (image reading operation relating to a document) with respect to each document, the multi-function peripheral1performs a reading operation at a timing before a predetermined position set between (or space between) the present document and an immediately preceding document (or immediately following document) reaches the reading position P (that is, including the timing before the usual image reading operation is started). In other words, as shown inFIG. 4, in addition to performing the usual image reading operation with respect to nthdocuments (n is integer equal to or greater than 1), the multi-function peripheral1also performs a respective reading operation in a predetermined position Cn−1 between a rear edge of the (n−1)-th document and a leading edge of the n-th document (or in a predetermined position Cn+1 between a rear edge of the n-th document and a leading edge of the (n+1)-th document).

Then, the multi-function peripheral1determines whether image data generated by the foreign matter (referred to hereinbelow as foreign-matter image data) are contained in the image data obtained in the reading operation and detects a position of the foreign matter (in particular, a position in the main scanning direction) on the basis of the foreign-matter image data in a case where the foreign-matter image data are determined to be contained.

InFIG. 4, a path along which the documents are conveyed to the reading position P by the document conveying unit21is assumed to be a straight line and a state is shown in which the documents that are sequentially conveyed by the document conveying unit21to the reading position P are arranged in a row.

In this case, the multi-function peripheral1has two modes as operation modes of each unit in a case where the foreign-matter image data are detected. Thus, the multi-function peripheral1has a foreign-matter image removal mode in which image processing for removing the foreign-matter image (the below-described foreign-matter image removal processing) is performed on the basis of image data obtained in the reading operation of the scanner unit22and an image is formed on the recording paper or data are saved on the basis of image data after the image processing, and a reading stop mode in which the reading operation is interrupted and a location of the foreign matter is made known, without performing the foreign-matter image removal processing.

The multi-function peripheral1of the present is configured so that the user can select the desired mode from the above-described two modes. This mode selection can be performed, for example, on a mode selection screen G1shown inFIG. 2. By performing a predetermined operation with respect to the operation unit5, the user displays the mode selection screen G1shown inFIG. 2at the display unit51.

As shown inFIG. 2, the mode selection screen G1has displayed thereon a foreign-matter image removal mode setting button B1for selecting the foreign-matter image removal mode in which image processing is performed to remove the foreign-matter image when the foreign-matter image is detected and a reading stop mode setting button B2for selecting a mode in which the reading operation is interrupted and a location of the foreign matter is made known when the foreign-matter image is detected. Where the foreign-matter image removal mode setting button B1or reading stop mode setting button B2is pushed, a mode instruction signal that indicates a mode corresponding to the button is outputted from the touch panel52to the control unit61.

In order to realize the above-described function, as shown inFIG. 3, the control unit61has functions of a foreign-matter image position detection unit611, a lighting control unit612, a drive control unit613, a reading control unit614, an image processing unit (image removal processing unit)615, a setting unit616, a display control unit617, a determination unit618, and a reading position derivation unit619.

The foreign-matter image position detection unit611detects a predetermined foreign-matter image from the image read by the scanner unit22in a state in which a document conveyed by the document conveying unit21comes off from the document glass of the document reading position230(before the document is sent, or between a document that has been heretofore sent and the document that will be set thereafter) and detects the main scanning direction position of the foreign-matter image in the main scanning direction of the scanner unit22.

The foreign-matter image position detection unit611detects the presence of foreign-matter image generated by the foreign matter and detects indirectly the presence of foreign matter on the document glass on the basis of image data obtained in the reading operation performed by the scanner22. As mentioned hereinabove, because the surface of the conveying drum213that faces the document reading window230is a monochromatic white surface, in the reading operation performed at a timing in which the position Cn−1 passes by the reading position P, this white surface is irradiated by the light from the light source222of the scanner unit22.

Therefore, in a case where no foreign matter is present on the document glass (document reading window230) at a timing in which the position Cn−1 passes by the reading position P, image data of one line in the main scanning direction that are obtained at this timing have a comparatively large pixel value corresponding to white color uniformly in the main scanning direction.

In a case where foreign matter is present on the document reading window230at a timing in which the position Cn−1 passes by the reading position P, image data of one line in the main scanning direction that are obtained at this timing include image data with a pixel value reduced by the foreign matter among the image data with comparatively large pixel values.

Based on this information, the foreign-matter image position detection unit611performs a processing of detecting an image (referred to hereinbelow as “foreign-matter image”) caused by the foreign matter. Thus, the foreign-matter image position detection unit611determines whether pixel data with a pixel value below a predetermined threshold are present among pixel data with comparatively larger pixel values with respect to image data obtained by the reading operation performed at a timing in which the position Cn−1 passes by the reading position P, and when pixel data with a pixel value below a predetermined threshold are present among pixel data with comparatively larger pixel values, the foreign-matter image position detection unit detects the image data with a pixel value below a predetermined threshold as foreign-matter image data.

The foreign-matter image position detection unit611then analyzes which pixels of the scanner unit22that are arranged in a row in the main scanning direction generate the pixel data constituting the foreign-matter image and detects the position of the foreign-matter image in the main scanning direction.

The lighting control unit612controls the lighting of the light source222of the scanner unit22. In a case where the foreign-matter image is detected by the foreign-matter image position detection unit611, the lighting control unit612lights up a group of light-emitting elements of the light source222that are arranged in a row in the main scanning direction and also lights up the light-emitting elements provided in a predetermined range from the main scanning direction position of the foreign-matter image in a light emission mode that is different from that of other light-emitting elements. The different light emission modes, as referred to herein, for example, include: (1) a mode in which the quantity of light of the light-emitting elements provided in the predetermined range is larger than that of other light-emitting elements; (2) a mode in which the light-emitting elements provided in the predetermined range are dimmed, whereas other light-emitting elements emit light at a normal level; and (3) a mode in which the emission amount of the light-emitting elements provided in the predetermined range is periodically increased and decreases, whereas other light-emitting element emit light at a constant emission amount at all times.

A drive control unit613drive controls a moving mechanism configured, for example, by a motor (not shown in the figure) that moves the first carriage226and second carriage227of the scanner unit22in the sub-scanning direction (direction perpendicular to the main scanning direction) of the scanner unit22. The moving mechanism is provided at the document reading mechanism200.

The reading control unit614controls the document reading operation of the scanner unit22. The reading control unit614controls the reading operation of each unit of the document reading mechanism200, for example the document conveying unit21and scanner unit22. In particular, in the present embodiment, the reading control unit614causes the scanner unit22to perform the usual image reading operation for each document and additionally causes the scanner unit22to perform a reading operation at a timing at which the position Cn−1 (n is integer equal to or greater than 1) passes by the reading position P.

The image processing unit615performs image processing relating to image data. For example, the image processing unit615performs correction processing such as shading correction, level correction, gamma correction, color aberration correction, MTF (Modulation Transfer Function) correction, and scanner color correction, image data compression or expansion processing, and image processing such as enlargement and reduction processing with respect to image data acquired by the CCD229or image data transferred from a personal computer connected to the network or a facsimile apparatus connected to the public circuit.

Where the foreign-matter image is detected by the foreign-matter image position detection unit611, the image processing unit615implements a foreign-matter image removal processing for removing the foreign-matter image with respect to the image data corresponding to the abovementioned mode that has been set. A well-known image processing such as a processing in which an average of a plurality of image data constituting the images positioned around the foreign-matter image is computed and the average data are used instead of the foreign image data can be used as the foreign-matter image removal processing.

The setting unit616sets a mode of the multi-function peripheral1on the basis of a mode instruction signal outputted by the operation unit5when the above-described foreign-matter image removal mode setting button B1or reading stop mode setting button B2on the touch panel52is operated by the user. Thus, (a) when the foreign-matter image removal mode is indicated by the mode instruction signal, where foreign matter is detected by the foreign-matter image position detection unit611, the foreign-matter image removal processing is performed with respect to the image obtained by the document reading operation performed by the scanner unit22, and an image is formed on the recording paper or the image is saved based on the image after the image processing; and (b) when the reading stop mode is indicated by the mode instruction signal, where foreign matter is detected by the foreign-matter image position detection unit611, the reading operation performed by the scanner unit22is stopped and the location of foreign matter is notified to the light source222of the document reading unit22, without performing the foreign-matter image removal processing.

The display control unit617drive controls the display unit51and, for example, causes the display unit51to display the foreign-matter image removal mode setting button B1or reading stop mode setting button B2and also causes the display unit51to display or not display an instruction input button (FIG. 13) that serves to receive from the user an instruction to stop the lighting of the light-emitting element group of the light source222of the scanner unit22when the foreign-matter image position detection unit611performs foreign image detection.

The determination unit618determines whether the processing of removing the foreign-matter image by the image processing unit615can be performed. For example, the determination unit618determines whether the foreign-matter image detected by the foreign-matter image position detection unit611is constituted by a pixel group confined in a region of the predetermined range, in a case where the foreign-matter image is constituted by a pixel group confined in this range, the determination unit determines that the processing of removing the foreign-matter image by the image processing unit615can be performed. In a case where the foreign-matter image is constituted by a pixel group that is not confined in this region of the aforementioned range, the determination unit determines that the processing of removing the foreign-matter image by the image processing unit615cannot be performed. However, the determination unit618may determine whether the foreign-matter image removal processing is possible based on whether the foreign-matter image present in one continuous region is constituted by a pixel group confined in the aforementioned range, and also may determine whether the foreign-matter image removal processing is possible based on whether the sum total region of a pixel group of the foreign-matter images present in a plurality of different regions is confined in the range.

In a case where the foreign-matter image is detected by the foreign-matter image position detection unit611, the reading position derivation unit619detects a sub-scanning direction position in which foreign matter has hot adhered within the document reading window230and derives this position as a change destination of reading position of the scanner unit22.FIG. 5shows a state in which the reading position of the scanner unit22is changed from the reading position P to the reading position P′ when foreign matter D is present in the reading position P.

The configuration of the light source222of the scanner unit22will be explained below.FIG. 6is a top view of the light source222andFIG. 7is a side sectional view in which the light source222and document glass are extracted.

As shown inFIG. 6, in the light source222, light-emitting element groups in which a plurality of light-emitting elements (for example, composed by LED (Light Emitting Diode)) are provided side by side in the main scanning direction are provided in two rows arranged in the sub-scanning direction, which is a document conveying direction in which the documents are conveyed by the document conveying unit21. The respective light-emitting element groups are denoted by reference symbols200A and200B. As described hereinabove, the light source222illuminates the document that has been conveyed to the document reading window230, and when the document is read, the document that has been conveyed to the document reading position is illumined by both light-emitting element groups200A and200B of the two rows.

As shown inFIG. 7, in the light-emitting element group200A located on the upstream side in the document conveying direction, the light-emitting elements LA1. . . LAn are oriented so as to emit light toward the downstream side in the document conveying direction. In the light-emitting element group200B located on the downstream side in the document conveying direction, the light-emitting elements LB1. . . LBn are oriented so as to emit light toward the upstream side in the document conveying direction. The orientation of the light-emitting elements LA1. . . LAn and light-emitting elements LB1. . . LBn and the height position of the light source222are set such that the illumination light of the light-emitting elements LA1. . . LAn and the illumination light of light-emitting elements LB1. . . LBn are united in a position of the document reading window230(document glass).

Further, when a foreign-matter image is detected by the foreign-matter image position detection unit611, the light-emitting element group200A on the upstream side in the document conveying direction is mainly used for illuminating the contamination (dirt, dust, defects, and the like) detected on the document glass. The light-emitting element group200B on the downstream side in the document conveying direction is used for illuminating the entire document glass extending in the main scanning direction.

When the foreign-matter image is detected by the foreign-matter image position detection unit611, the moving mechanism of the light source222is driven by the drive control unit613and moved to a position (sub-scanning direction position of the light source222in which the illumination light does not reach the position at the predetermined distance from the document glass) indicated by the sub-scanning direction position information that has been stored in the storage unit67, and then the below-described lighting of the light-emitting element groups200A and200B is performed by the lighting control unit612. The position at the predetermined distance from the document glass, as referred to herein, is a height position of the user's eyes with respect to the height position of the document glass in a case where the user of a standard height is assumed to look on the document glass from above the document glass. In this case, for example, the position of the user's eyes is directly above the document glass, the light source222is moved by the drive control unit613in the sub-scanning direction from the document illumination position during document reading to a position indicated by the sub-scanning direction position information, this position being on the downstream side or upstream side in the document conveying direction, and then the above-mentioned lighting control is performed by the lighting control unit612in a case where contamination is detected on the document glass.

As shown inFIGS. 6 and 7, a slit2261is provided in a position on the first carriage226between the light-emitting element groups200A and200B in the sub-scanning direction. A first mirror223is disposed below the slit2261, and the image illuminated by the light-emitting element groups200A and200B through the slit2261is read by the CCD229via the first mirror223, second mirror224, third mirror225, and converging lens228.

The processing of contamination detection on the document glass and contamination notification in the multi-function peripheral1will be described below. First, the mode setting processing will be explained.FIG. 8is a flowchart illustrating the mode setting processing.

As described hereinabove, the multi-function peripheral1is provided with a foreign-matter image removal mode in which image processing is performed to remove the foreign-matter image and a reading stop mode in which the reading operation performed by the scanner unit22is interrupted and the location of the foreign matter is notified to the user, without performing the image processing that removes the foreign-matter image, as operation modes used in a case where the foreign-matter image is detected in the image read with the scanner unit22.

For example, where the user pushes the mode setting button59(FIG. 2) of the operation unit5, an instruction causing the display control unit617to display the mode setting screen in the display unit51is received by the display control unit617(YES in S1). In this case, the display control unit617causes the display unit51to display the mode setting screen G1such as shown inFIG. 2(S2). In a case where the reading stop mode setting button B2for selecting the reading stop mode is pushed by the user in the mode setting screen G1(YES in S3), the setting unit616sets a mode to be used during contamination detection in the multi-function peripheral1to the reading stop mode (S4). By contrast, in a case where the user pushes the foreign-matter image removal mode setting button B1for selecting the foreign-matter image removal mode (NO in S3), the setting unit616sets a mode to be used during contamination detection in the multi-function peripheral1to the foreign-matter image removal mode (S5).

The contamination detection on the document glass and contamination notification processing performed with the multi-function peripheral1will be explained below.FIG. 9is a flowchart showing the first embodiment of contamination detection on the document glass and contamination notification processing performed with the multi-function peripheral1.

Where, for example, a copying operation start instruction is inputted with the start button55(YES in S11), the reading control unit614causes the scanner unit22to read the image on document glass prior to causing the document conveying unit21to convey the document located on the document tray211(S12). Then, the foreign-matter image position detection unit611performs a processing of detecting the foreign-matter image from the image that has been read by the scanner unit22(S13). In step S13, in a case where the foreign-matter image position detection unit611has detected the foreign-matter image, this unit also detects the main scanning direction position of the foreign-matter image.

In a case where the foreign-matter image position detection unit611has not detected the foreign-matter image from the image that has been read by the scanner unit22(NO in S14), the reading control unit614causes the scanner unit22to perform a document reading operation for the usual copying operation (S19) and the control unit61causes the image forming unit40to perform an image forming operation based on the image obtained in the document reading operation (S20).

In a case where the foreign-matter image position detection unit611has detected the foreign-matter image from the image that has been read by the scanner unit22(YES in S14), the control unit61determines whether the mode of the multi-function peripheral1that has been presently set by the setting unit616is a reading stop mode or a foreign-matter image removal mode (S15).

Where the control unit61determines that the mode that has been presently set is a reading stop mode (YES in S15), the drive control unit613causes the moving mechanism to move the first carriage226and the second carriage227to the sub-scanning direction position indicated by the sub-scanning position information stored in the storage unit67(S16). Then, the lighting control unit612causes all the light-emitting elements of the light-emitting element groups200A and200B to emit light and illuminate the document glass and also lights up the light-emitting elements provided in the abovementioned fixed range in the vicinity of the main scanning direction position of the detected foreign-matter image, from among the light-emitting elements LA1. . . LAn of the light-emitting element group200A, in any one of the above-described light emission modes (1) to (3) (S17).

As a result, where the user rotates the document conveying unit21upward and opens up the document glass from above, the lighting of the light-emitting elements in the main scanning direction position where the foreign matter is present makes it possible to grasp the contamination position on the document glass and also grasp the contamination in other locations on the document glass.

By contrast, where the control unit61determines that the mode that has been presently set is a foreign-matter image removal mode (NO in S15), the determination unit618performs the above-described determination processing of determining whether the foreign-matter image removal processing with the image processing unit615is possible, this determination being conducted on the basis of the size of the region where the detected foreign-matter image is present (S21). In this case where the determination unit618determines that the foreign-matter image removal processing of the foreign-matter image is impossible (NO in S21), the processing flow moves to S16.

In a case where the determination unit618determines that the foreign-matter image processing of the foreign-matter image is possible (YES in S21), the reading control unit614causes the document conveying unit21and scanner unit22to perform the document reading operation for the usual copying operation (S22), and the image processing unit615performs the foreign-matter image removal processing with respect to the image that has been read (S23). The control unit61causes the image forming unit40to form an image on the recording paper on the basis of the image after the foreign-matter image removal processing has been removed (S24).

As a result, where the contamination of the document glass is very small and the foreign-matter image can be eliminated by image processing, the user can perform the document reading and image formation directly, without stopping the document reading operation, and where the document glass contamination is significant and the cancelation of the foreign-matter image by image processing is insufficient, the document reading operation can be stopped, the user can be notified about the position of contamination on the document glass and the user can perform wiping or the like in the contamination position.

The second embodiment of the contamination detection on the document glass and contamination notification processing performed with the multi-function peripheral1will be explained below.FIG. 10is a flowchart showing the second embodiment of the contamination detection on the document glass and contamination notification processing performed with the multi-function peripheral1. The explanation of processing similar to that of the first embodiment is herein omitted.

In the first embodiment, the contamination detection on the document glass and contamination notification processing are performed before the document reading operation in the copying operation is started, but in the second embodiment the contamination detection on the document glass and contamination notification processing are performed after the document reading operation in the copying operation has been started.

In the second embodiment, for example, where the copying operation start instruction is inputted from the start button55(YES in S31), the reading control unit614causes the document conveying unit21to convey a document located on the document tray211and starts the document reading with the scanner unit22(S32). The reading control unit614causes the scanner unit22to read the image on the document glass for foreign-matter image detection at a timing (Cn−1 or others shown inFIG. 4) within an interval in which each document is conveyed to the document reading window230(document glass) by the document conveying unit21(S34). In parallel with other processing operations that have to be performed during the copying operation, the processing of detecting the foreign-matter image from the image read with the scanner unit22is performed by the foreign-matter image position detection unit611(S35).

In a case where the foreign-matter image position detection unit611has not detected the foreign-matter image from the image read by the scanner unit22(NO in S36), the reading control unit614causes the scanner unit22to perform the document reading operation for the usual copying operation (S41), and in a case where the foreign-matter image has been detected (YES in S36) and also the control unit61has determined the reading stop mode (YES in S37), the reading control unit614causes the document conveying unit21and scanner unit22to stop the document reading operation (S38). The drive control unit613then causes the moving mechanism to move the light source222and the like to the sub-scanning direction position indicated by the sub-scanning direction position information stored in the storage unit67(S39), and the lighting control unit612notifies the contamination position on the document glass by lighting control of the light-emitting element groups200A and200B in any of the above-described light emission modes (1) to (3) (S40).

As a result, in a case where the document glass is contaminated, the user can grasp the contamination position on the document glass and also grasp the contamination in other locations on the document glass even after the document reading operation has been started.

In a case where the control unit61determines that the mode that has presently been set is the foreign-matter image removal mode (NO in S37), if the determination unit618determines that the foreign-matter image removal processing of the foreign-matter image is possible (YES in S43), the document reading operation is continued by the reading control unit614(S44), and image formation based on the image after the foreign-matter image removal processing has been performed by the image processing unit615is performed by the image formation unit40(S45, S46). Further, in a case where the determination unit618determines that the foreign-matter image removal processing of the foreign-matter image is impossible (NO in S43), the processing flow moves to S38and the reading control unit614causes the document conveying unit21and scanner unit22to stop the document reading operation.

The lighting control of the light source222in the above-described contamination detection embodiment performed by the multi-function peripheral1will be explained below.FIG. 11is a flowchart illustrating the lighting control of the light source222in the above-described contamination detection embodiment performed by the multi-function peripheral1.FIG. 12is a perspective view of the multi-function peripheral1showing a state in which the document conveying unit21is rotated upward.FIG. 13illustrates a display example of the display unit51.

In the multi-function peripheral1, in a case where the processing of steps S17and S40described in the first and second embodiments is conducted, the lighting control unit612can perform the lighting control of the light source222in the following manner.

The document conveying unit21is provided with a rotation mechanism600that can open and close the document conveying unit21in the direction shown by arrow A inFIG. 12(direction of coming into contact with and withdrawing from the platen glass221) by rotation about the rear edge of the document3as a rotation axis. An opening-closing detection switch500is configured to be switched off when the document conveying unit21is withdrawn by the rotation mechanism600from the upper surface of the body3where the platen glass221and the document glass are provided and switched on when the document conveying unit21is brought into contact with the upper surface of the body3by the rotation mechanism600. The opening-closing detection switch500outputs the signals indicating the ON and OFF state of the switch to the control unit61(lighting control unit612).

In a case where processing of steps S17and S40in the first and second embodiments is performed, the lighting control unit612determines whether the opening-closing detection switch500is switched on or off on the basis of the abovementioned signals outputted by the opening-closing detection switch500(S51). In a case where the opening-closing detection switch500is switched off (YES in S51), the lighting control unit612notifies the light source222about the contamination position on the document glass by the above-mentioned lighting control of the light-emitting element groups200A and200B (S52). As shown inFIG. 13, the display control unit617then displays at the display unit51a lighting turn-off instruction input and reception button B3that receives a lighting notification end instruction (instruction to end the notification by the lighting control of the light-emitting element groups200A and200B of the light source222) from the user (S53).

Where the lighting notification end instruction is inputted by the user operation of the lighting turn-off instruction input and reception button B3(YES in S54), the lighting control unit612ends the contamination position notification by the lighting control of the light-emitting element groups200A and200B (S55). Thus, the lighting control unit612turns off the light-emitting elements200A and200B of the light source222. Then, the display control unit617stops the display of the lighting turn-off instruction input and reception button B3at the display unit51(S56).

Where the lighting notification end instruction is not inputted by the user by the lighting turn-off instruction input and reception button B3(NO in S54), the lighting control unit612continuous detecting whether the signal of the opening-closing detection switch500indicates that the switch is on or off (S57), and where the signal of the opening-closing detection switch500is off (NO in S57), the processing flow returns to S54, and where the signal of the opening-closing detection switch500is on (YES in S57), the processing flow returns to S55.

With the above-described processing, when the document conveying unit21is withdrawn from the document glass (document reading window230) and the user can see the document glass, the contamination position notification by the lighting control of the light-emitting element groups200A and200B during the foreign-matter image detection can be performed at a timing meaningful for the user.

The present invention is not limited to the configurations of the above-described embodiments, and a variety of changes can be made. For example, in the above-described embodiments, the light source222is configured to have two rows of light-emitting element groups200A and200B shown inFIG. 6, but instead a configuration may be used in which a light-emitting element group of only one row is provided, the lighting control unit612lights up all the light-emitting elements of the one-row light-emitting element group, illuminates the document glass, and lights up the light-emitting elements provided in the abovementioned fixed range in the vicinity of the main scanning direction position of the detected foreign-matter image, from among the light-emitting elements of the light-emitting element group, in any of the above-described light emission modes (1) to (3).

In a case where the foreign-matter image is detected and the document reading operation is not performed in the contamination detection on the document glass and contamination notification processing described in the first embodiment, or in a case where the foreign-matter image is detected and the document reading operation is stopped in the second embodiment (S38inFIG. 10), a configuration may be used in which the drive control unit613changes the position of reading with the scanner unit22in the ADF reading mode to the sub-scanning direction position to which foreign matter has not adhered on the document reading window230, this position being detected by the reading position derivation unit619, and then the reading control unit614restarts the document reading operation.

The configurations and processing illustrated byFIGS. 1 to 13in the above-described embodiments are exemplary and the present invention should not be construed as being limited to the embodiments.

Essentially, the present invention relates to an image reading device including: a document reading unit having an illumination mechanism, which illuminates a document with a group of a plurality of light-emitting elements arranged side by side in a main scanning direction, and reading optically an image of the document illuminated by the illumination mechanism via a document glass that extends in the main scanning direction in a predetermined document reading position; a document conveying unit that conveys the document in a sub-scanning direction of the document reading unit with respect to the document reading position; a foreign-matter image position detection unit that detects a predetermined foreign-matter image from the image read by the document reading unit when the document conveyed by the document conveying unit comes off from the document reading position and detects a main scanning direction position of the foreign-matter image in the main scanning direction; and a lighting control unit that lights up the light-emitting element group arranged in the main scanning direction and lights up the light-emitting elements within a predetermined range from the main scanning direction position of the foreign-matter image in a light emission mode that is different from that of other light-emitting elements when the foreign-matter image is detected by the foreign-matter image position detection unit.

The present invention further relates to the image reading device, wherein in the illumination mechanism, the groups of a plurality of light-emitting elements arranged side by side are provided in two rows arranged in the sub-scanning direction; and in a case where the foreign-matter image is detected, the lighting control unit lights up the light-emitting element group of one row, and with respect to the light-emitting element group of the other row, the lighting control unit lights up, in the different light emission mode, only light-emitting elements located in a predetermined range from the main scanning direction position of the foreign-matter image.

According to the above-described aspects of the invention, in a case where a foreign-matter image is detected by the foreign-matter image position detection unit in the document reading position when the document comes off from the document reading position, the lighting control unit lights up the light-emitting element group arranged side by side in the main scanning direction and lights up the light-emitting elements within a predetermined range from the main scanning direction position in which the foreign-matter image is present in a light emission mode that is different from that of other light-emitting elements. As a result, the foreign-matter image position detection and a reading operation for the foreign-matter image position detection can be performed before the document is read. Therefore, contamination in the document reading position (that is, on the document glass disposed in the document reading position) can be detected at a point in time before the document is read, that is, substantially when the document reading by the document reading unit has not been started. Furthermore, by lighting up the group of light-emitting elements arranged side by side in the main scanning direction, the user can be informed about the contamination state of other zones on the document glass. Moreover, because the light-emitting elements within a predetermined range from the main scanning direction position in which the foreign-matter image is present are lighted up in a light emission mode different from that of other light-emitting elements, the user can be notified about the contamination location on the document glass.

Thus, in the conventional document reading device, the user is notified after the document has been read. Therefore, once the document reading processing has been started, the user will not be aware about the presence of a stripe-like image till the document reading job or copying job is completed. Furthermore, the notification after the document is read cannot provide the user with information relating to the position of contamination on the document glass. In a case of the conventional image reading device in which only the contamination location on the document glass is displayed by lighting, the user does not know the level of contamination in other locations on the document glass. As a result, even zones with a lot of dust can remain without being cleaned. By contrast, in accordance with the present invention, contamination present on the document glass can be detected before the document is read, and the user can be notified about the contamination location on the document glass and contamination state of other locations.

The present invention further relates to the image reading device, wherein the document reading unit that includes the illumination mechanism further includes a moving mechanism capable of moving in the sub-scanning direction, the image reading device further including a storage device that stores information on a sub-scanning direction position of the illumination mechanism in which illumination light does not reach a position at a predetermined distance from the document glass; and a drive control unit that drive controls the moving mechanism, wherein in a case where the foreign-matter image is detected, the drive control unit causes the moving mechanism to move the illumination mechanism into a position indicated by the sub-scanning direction position information, and then the lighting control unit performs lighting control of the light-emitting element group during the foreign-matter image detection.

In accordance with the invention, in a case where the foreign-matter image is detected, the drive control unit causes the movement of the illumination mechanism into the sub-scanning direction position in which illumination light does not reach a position at a predetermined distance from the document glass, and then the lighting control unit performs lighting control of the light-emitting element group during the foreign-matter image detection. Therefore, the position at a predetermined distance from the document glass is set in a position of the user's eyes that is normally assumed to be above the document glass, thereby making it possible to notify the user about the contamination location and other locations on the document glass by the lighting control of the light-emitting element group during the foreign-matter image detection, without dazzling the user.

The present invention further relates to the image reading device, further including a reading control unit that controls a document reading operation of the document reading unit, wherein the reading control unit performs the foreign-matter image position detection and a reading operation by the document reading unit for the foreign-matter image position detection before the document is conveyed by the document conveying unit.

In accordance with the invention, the foreign-matter image position detection and a reading operation with the document reading unit for the foreign-matter image position detection are performed before the document is conveyed by the document conveying unit. Therefore, contamination in the document reading position (on the document glass) can be detected substantially at a point in time before the document is read by the document reading unit.

The present invention relates to the image reading device, further including a reading control unit that controls a reading operation of the document reading unit, wherein in a case where the foreign-matter image is detected after the document reading operation has been started by the document reading unit, the reading control unit causes the document reading unit to interrupt the document reading operation, and then the lighting control unit performs lighting control of the light-emitting element group during the foreign-matter image detection.

In accordance with the invention, where the foreign-matter image is detected after the document reading operation has been started, the reading control unit causes the document reading unit to stop the document reading operation, and then the lighting control unit performs lighting control of the light-emitting element group during the foreign-matter image detection. Therefore, the user can be notified about the contamination location and other locations on the document glass, while avoiding a state in which the document reading operation is continued despite the presence of contamination in the document reading position (on the document glass).

The present invention further relates to the image reading device, further including: an image removal processing unit that removes the foreign-matter image by image processing from a document image that has been read by the document reading unit; and a determination unit that determines whether a removal processing of the foreign-matter image by the image removal processing unit is possible, wherein in a case where the determination unit determines that the image removal processing is possible when the foreign-matter image is detected, the image removal processing unit removes the foreign-matter image from the document image that has been read, and in a case where the determination unit determines that the image removal processing is impossible, the lighting control unit performs lighting control of the light-emitting element group during the foreign-matter image detection.

In accordance with the invention, where the determination unit determines that the foreign-matter image can be removed by image processing, the foreign-matter image removal processing is performed, and where the determination unit determines that the image removal processing is impossible, the lighting control of the light-emitting element group is performed during the foreign-matter image detection. Therefore, for example, where the document glass contamination is such that no effect is produced on printing during copying, the document reading and printing are completed without performing the lighting control of the light-emitting elements during the foreign-matter image detection, and where the document glass contamination can produce an adverse effect on printing during copying, the convenience for the user can be increased, for example by making the user aware about the contamination by the lighting control of the light-emitting elements during the foreign-matter image detection.

The present invention relates to the image reading device, further including: a setting unit that sets the image removal processing unit to perform the removal processing of a foreign-matter image, according to an instruction inputted by a user, wherein in a case where no setting is made to perform by the setting unit the image removal processing, the image removal processing unit does not perform the removal processing of the foreign-matter image, and the lighting control unit performs lighting control of the light-emitting element group during the foreign-matter image detection.

In accordance with the invention, the user can select, as desired, at the setting unit whether or not to perform the foreign-matter image removal processing. Therefore, it is also possible to perform the document reading after actually removing the contamination from the document glass, thereby increasing quality of the image obtained by document reading.

The present invention further relates to the image reading device, wherein the document conveying unit includes: a rotation mechanism that can rotate in a direction of coming into contact with or withdrawing from the document glass; and an opening-closing detection unit that detects an open-close state of the document conveying unit rotated by the rotation mechanism and outputs a signal indicating the open-close state to the lighting control unit; and when the lighting control unit receives from the opening-closing detection unit a signal indicating that the document conveying unit has been rotated by the rotation mechanism in the direction of withdrawing from the document glass and assumed an open state in a case where the foreign-matter image has been detected, the lighting control unit performs lighting control of the light-emitting element group during the foreign-matter image detection.

In accordance with the invention, in a case where the foreign-matter image is detected and the document conveying unit is rotated by the rotation mechanism in the direction of withdrawing from the document glass, the lighting control unit performs lighting control of the light-emitting element group during the foreign-matter image detection. Therefore, it is possible to light up the light-emitting element groups during the foreign-matter image detection at a timing meaningful for the user, for example, to light up the light-emitting element groups during the foreign-matter image detection only when the document conveying unit is withdrawn from the document glass and the user can see the document glass.

The present invention further relates to the image reading device, wherein when the lighting control unit receives from the opening-closing detection unit a signal indicating that the document conveying unit has been brought into contact with the document glass by rotation by the rotation mechanism and assumed a closed state, the lighting control unit stops the lighting control of the light-emitting element group during the foreign-matter image detection and turns off the light.

In accordance with the invention, where the document conveying unit is brought into contact with the document glass by rotation by the rotation mechanism, the lighting control unit stops the lighting control of the light-emitting element group during the foreign-matter image detection and turns off the light. Therefore, when the document conveying unit covers the document glass and comes into contact therewith and the user cannot see the document glass, the light-emitting element group is not lighted up during the foreign-matter image detection and useless light emission from the light-emitting elements can be avoided.

The present invention relates to the image reading device, further including: a display unit that has a touch panel function and displays an instruction input button for receiving from a user an instruction to stop the lighting of the light-emitting element group during the foreign-matter image detection; and a display control unit that drive controls the display unit, wherein the display control unit causes the display unit to display the instruction input button when lighting of the light-emitting elements during the foreign-matter image detection is started by the lighting control unit, and when a lighting stop instruction relating to the light-emitting elements is received from the user via the instruction input button, the lighting control unit stops the lighting control of the light-emitting element group during the foreign-matter image detection and turns off the light.

In accordance with the invention, by inputting the instruction to stop the lighting of the light-emitting element group during the foreign-matter image detection via the instruction input button of the display unit, the user can stop the lighting of the light-emitting element group during the foreign-matter image detection at the desired timing.

The present invention relates to the image reading device, wherein, when the lighting control unit receives from the opening-closing detection unit a signal indicating that the document conveying unit has been brought into contact with the document glass by rotation by the rotation mechanism and assumed a closed state, the lighting control unit stops the lighting control of the light-emitting element group during the foreign-matter image detection and turns off the light, and stops the display of the instruction input button at the display unit.

In accordance with the invention, when the document conveying unit comes into contact with the document glass and the light-emitting element group is turned off, the instruction input button that receives an instruction to stop the lighting of the light-emitting element group is not displayed by the display. Therefore, it is possible not to display at the display unit the instruction input button that is useless to the user.

The present invention relates to an image forming apparatus including: the image reading device according to the invention; and An image forming unit that performs image formation on a recording medium on the basis of a document image that has been read by the document reading unit.

This application is based on Japanese Patent application serial No. 2008-192353 filed in Japan Patent Office on Jul. 25, 2008, the contents of which are hereby incorporated by reference.