JP5201339B2 - Document reading apparatus and image forming apparatus - Google Patents

Description

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

  Japanese Patent Application Laid-Open No. 2005-133867 discloses a separating unit that separates a lightness signal into a chromaticity signal from an input color signal, a determining unit that determines chromatic / achromatic according to the chromaticity signal, and a predetermined color from the determining unit A color image processing apparatus having a control unit to be excluded is disclosed.

Japanese Patent Laid-Open No. 4-90675

  SUMMARY OF THE INVENTION An object of the present invention is to provide a document reading apparatus and an image forming apparatus that can prevent erroneous detection when detecting whether a document image is monochromatic or multicolored.

According to the first aspect of the present invention, there is provided a transmission unit that transmits light, and a reading unit that irradiates light on a document placed on the transmission unit and reads an image of the document based on reflected light from the document of the irradiated light. An opening / closing portion that can be opened and closed so as to cover the transmission portion in a closed state, an opening / closing detection means that detects an opening / closing state of the opening / closing portion, and a document that detects the size of the document placed on the transmission portion A detection unit; a color detection unit that detects whether the document is monochromatic or multi-colored from an image in a predetermined detection area of the document placed on the transmission unit; and a control unit that controls the color detection unit And the control unit detects that the opening / closing unit is opened by the opening / closing detection unit, and the size of the document detected by the document detection unit, and the reading unit. The size of the document reading area where the document is scanned by Comparison, if the size of the document reading region is larger than the size of the document detected by the document detecting unit, the size of the document detected by the document detecting unit as the detection region, the document is a monochrome When the color detection unit is controlled to detect whether the color is multicolor or the open / close detection unit detects that the open / close unit is closed, the document is read using the document reading area as the detection area. An original reading apparatus that controls the color detection unit to detect whether a single color or multiple colors .

  The present invention according to claim 2 is the case where the control unit detects that the opening / closing unit is opened by the opening / closing detection unit, and the size of the document reading area is determined by the document detection unit. 2. The color detection unit according to claim 1, wherein when the size of the original is not larger than the detected original, the color detection unit is controlled so as to detect whether the original is monochromatic or multicolored using the original reading area as the detection area. This is a document reading device.

According to a third aspect of the present invention, there is provided the document reading device according to the first or second aspect and an image forming unit that forms an image based on image information read by the document reading device according to the first or second aspect. The image forming apparatus.

According to the first aspect of the present invention, it is possible to prevent erroneous detection when detecting whether an image of a document is monochromatic or multicolored, and when the opening / closing portion is closed, It is possible to provide a document reading apparatus that can detect a document as multicolor even when only a portion outside the size of the detected document in the document reading area is multicolor .

  According to the second aspect of the present invention, in addition to the effect of the present invention according to the first aspect, when the opening / closing part is opened, the portion of the original reading area outside the detected size of the original is detected. Thus, it is possible to provide a document reading apparatus that can detect a document as being multi-colored even when only the document is multi-colored.

According to the third aspect of the present invention, it is possible to prevent erroneous detection when detecting whether an image of a document is single color or multicolor, and a document detected in the document reading area. Therefore, it is possible to provide an image forming apparatus that can detect a document as being multi-colored even when only a portion outside the size is multi-colored .

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes a document reading device 100 and an image forming unit 12 that forms an image based on image information read by the document reading device 100. The image forming unit 12 is of an electrophotographic type, for example, and has a sheet storage container 16 that stores sheets in a stacked state, and forms an image on the sheet supplied from the sheet storage container 16 to the sheet conveyance path 20. It is supposed to be.

  The image forming unit 12 includes an image forming unit main body 14. In the image forming unit main body 14, for example, an image holding member 22 using a photosensitive drum, and a charger 24 that uniformly charges the image holding member 22. An exposure device 26 that forms a latent image on the image carrier 22 uniformly charged by the charger 24; and a developing device 28 that visualizes the latent image on the image carrier 22 formed by the exposure device 26 with toner. A primary transfer device 32 for transferring the toner image formed by the developing device 28 to an intermediate transfer belt 30 used as an intermediate transfer member, and a photoreceptor cleaner 34 for cleaning the toner remaining on the image holding member 22 are mounted. ing.

  Further, in the image forming unit main body 14, a secondary transfer device 38 that transfers the toner image transferred to the intermediate transfer belt 30 to the sheet, a fixing device 40 that fixes the paper transferred to the sheet to the sheet, An intermediate transfer belt cleaner 44 for cleaning the intermediate transfer belt 30 is mounted.

  For example, an operation panel 302 used as a user interface is mounted on the front side of the image forming unit main body 14, for example, and a sheet on which image formation has been performed is discharged on the right side of the image forming unit main body 14, for example. A discharge portion 42 is attached.

  The exposure device 26 is of, for example, a laser scanning type, and outputs image information of a document read by a photoelectric conversion element 138 (see FIG. 2), which will be described later, included in the document reading device 100 instead of a laser on / off signal. The developing device 28 is, for example, a rotary type, and has Y, M, C, and K four color developing devices 36a, 36b, 36c, and 36d, for example, arranged in the periphery, and holds an image when developing each color. It rotates to face the body 22. The primary transfer device 32 is composed of, for example, a corotron, and the four-color toner images are transferred to the intermediate transfer belt 30 by the primary transfer device 32. The toner image transferred to the intermediate transfer belt 30 is transferred to a sheet by the secondary transfer device 38, this sheet is sent to the fixing device 40, the toner image is fixed to the sheet by the fixing device 40, and the toner image is fixed. The discharged sheet is discharged to the discharge unit 42. The toner remaining on the intermediate transfer belt 30 is scraped off by the intermediate transfer belt cleaner 44.

  The operation panel 302 selects, for example, whether the image forming unit 12 forms a single color image composed of a single black toner or a multicolor image formed of, for example, yellow, magenta, cyan, and black toner, A plurality of operation modes such as setting the magnification and image quality of an image can be selected. The operation panel 302 also sets a document reading area, which is a region when the document reading device 100 reads a document, a plurality of scan speeds (magnifications) at which the document reading device 100 reads a document, monochrome reading, or color reading. A plurality of operation modes such as a document conveying method and setting of a document size from a plurality of sizes can be selected.

  A resist roll 46 is disposed in the sheet conveyance path 20. The registration roll 46 is controlled to temporarily stop the supplied sheet and supply the sheet to the secondary transfer device 38 in synchronization with the timing at which the toner image is formed on the intermediate transfer belt 30.

  The document reading apparatus 100 includes a platen member 106 made of, for example, glass, which is used as a transmission portion that transmits light. The reading table 104 on which the document D is placed, and the reading table 104. The platen cover portion 110 is provided so as to be openable and closable and used as an opening and closing portion.

  The reading table 104 is formed as a housing. In the reading table 104, there is a reading unit 130 that irradiates light on the document placed on the platen member 106 and reads the document based on the reflected light of the irradiated light from the document. It is installed. A document transport device 160 that automatically transports the document D is mounted in the platen cover section 110. The document reading apparatus 100 has a function of flowing and reading the document D being conveyed by the document conveying device 160 and a function of reading the document D placed on the platen member 106.

FIG. 2 shows details of the document reading apparatus 100, and FIG. 3 shows the document reading apparatus 100 in a state where the platen cover unit 110 is opened with respect to the reading table 104.
As shown in FIGS. 2 and 3, the document reading apparatus 100 includes a hinge part 114 having a shaft 116, and the reading table 104 and the platen cover part 110 are connected by the hinge part 114. The platen cover unit 110 opens and closes with respect to the reading table 104 so as to rotate about the shaft 116. When the platen cover part 110 is closed, the platen member 106 is covered as shown in FIG. 2, and the document reading apparatus 100 has an open / close detection means for detecting the open / closed state of the platen cover part 110. An open / close sensor 304 is attached.

  The document transport device 160 includes a document table 162 on which a document before reading is set, a document transport path 164 that transports the document, and a discharge table 166 on which the document after reading the image is discharged. The document conveyance path 164 includes a main conveyance unit 168 and a reversing unit 170. The main conveyance unit 168 is formed in a U-shape, and in order from the upstream side in the document conveyance direction along the main conveyance unit 168, a pickup roll 172, a feed roll 174, a pre-registration roll 176, a registration roll 178, and an out. A roll 180 and a discharge roll 182 are provided.

  The pickup roll 172 descends when the document is fed and picks up the document placed on the document table 162. The feed roll 174 feeds the original sent from the pickup roll 172 and supplies only the uppermost original. The pre-registration roll 176 forms a loop by temporarily stopping the original fed from the feed roll 174, and performs skew correction. The registration roll 178 temporarily stops the document sent from the pre-registration roll 176 and takes the reading timing. When the document is discharged, the discharge roll 182 is rotated forward and discharged to the discharge table 166 via the out roll 180 and the discharge roll 182.

  One end of the reversing unit 170 is connected to the main transport unit 168 between the out roll 180 and the discharge roll 182, and the other end is connected to the main transport unit 168 on the upstream side of the pre-registration roll 176. An inversion gate 184 is provided near one end of the inversion unit 170. When the document is reversed, the discharge roll 182 is reversed when the rear end of the document reaches the vicinity of the discharge roll 182, and the document is guided to the reversing unit 170 by the reversal gate 184 being positioned below. The inversion gate 184 may be opened by the pressing force of the document and may be closed by the weight of the inversion gate 184, or an actuator for opening and closing the inversion gate 184 may be provided.

  In addition, a transported document reading position 186 is provided along the main transport unit 168, which is a position for reading a document when the document being transported is read. The transported document reading position 186 is provided between the registration roll 178 and the out-roll 180 so as to read the document sent by the document transport device 160.

  The reading unit 130 includes a full rate carriage 132, a half rate carriage 134, a lens 136, and a photoelectric conversion element 138. The full-rate carriage 132 has a light source 140 and a first mirror 142, and scans the reading table 104 with the document sub-scanning direction (from left to right in FIG. 2) as the scanning direction as indicated by arrows in FIG. Full stroke movement in the direction.

  The light source 140 is a lamp such as halogen or xenon that extends in the main scanning direction of the document, and has a predetermined scan width. The half-rate carriage 134 includes a second mirror 144 and a third mirror 146, and is configured to move within the reading table 104 by a half stroke in the sub-scanning direction.

  The lens 136 is a light source 140 that irradiates a document placed on the platen member 106 provided above the movement range of the full-rate carriage 132 and the half-rate carriage 134 or a document passing through the transported document reading position 186. The reflected light is received through the first mirror 142, the second mirror 144, and the third mirror 146 to form an image.

  The photoelectric conversion element 138 receives the reflected light at the imaging position of the reflected light by the lens 136 and, for example, analog signals corresponding to the respective RGB amounts of light by a photodiode provided with RGB filters (primary color filters). For example, it is a three-line color CCD that outputs an electrical signal to a processing circuit described later.

  A first reference white plate 150 that reflects the light emitted from the light source 140 is provided between the transported document reading position 186 and the platen member 106. The first reference white plate 150 has a white reflecting surface that reflects light. For example, when the image forming apparatus 10 is turned on, the light source 140 irradiates the first reference white plate 150. The photoelectric conversion element 138 can receive reflected light (initial reference light amount light) through the first mirror 142, the second mirror 144, the third mirror 146, and the lens 136.

FIG. 4 shows the reading table 104 with the platen cover 110 opened.
As shown in FIG. 4, second reference white plates 152 that reflect the light emitted from the light source 140 are provided at both ends of the conveyed document reading position 186, respectively. The second reference white plate 152 has a reflecting surface that reflects light as a reference white. For example, when the document reading apparatus 100 reads and reads a document, the light source 140 controls the second reference white plate 152. The photoelectric conversion element 138 can receive the reflected light (reference light amount light at the time of reading) irradiated through the first mirror 142, the second mirror 144, the third mirror 146, and the lens 136.

  When the operator places the original on the platen member 106, the upper surface of the reading table 104 and the upper surface of the first reference white plate 150 are, for example, A4, B4, and A3. Depending on the size and type, a guide used for document alignment is shown by a method such as printing. 4 indicate the positions of originals of respective sizes when the A4 original, the B5 original, and the A3 original are placed on the platen member 106, respectively.

  A document sensor 306 used as document detection means for detecting the size of the document placed on the platen member 106 is provided inside the reading table 104. A plurality of document sensors 306 are arranged in a discrete state, and the type and size of the document placed on the platen member 106 are detected by a combination of whether or not each document sensor 306 detects the document, It can be determined.

In the document reading apparatus 100 configured as described above, when reading a document placed on the platen member 106, the light source 140 emits light toward the document while the full rate carriage 132 and the half rate carriage 134 By moving in the scanning direction, the photoelectric conversion element 138 sequentially receives reflected light corresponding to the entire surface of the document.
When the original reading apparatus 100 reads and reads an original, the photoelectric conversion element 138 receives reflected light from the conveyed original for each original at the transported original reading position 186.

FIG. 5 shows a configuration of the document reading apparatus 100 as a block diagram.
As illustrated in FIG. 5, the document reading apparatus 100 includes the above-described photoelectric conversion element 138, an operation panel 302, an open / close sensor 304, and a document sensor 306. The document reading apparatus 100 includes sample hold circuits 202R, 202G, and 202B, output amplifier circuits 204R, 204G, and 204B, AD conversion circuits 206R, 206G, and 206B, shading correction circuits 208R, 208G, and 208B, and output delay. Circuits 210G and 210B, a color space conversion circuit 212, a color detection circuit 214, an image processing circuit 216, a CPC 218, and a drive circuit 220 are included.

  Here, the sample board circuit 202R, the output amplifier circuit 204R, the AD conversion circuit 206R, and the shading correction circuit 208B are used as a signal system for processing the analog image signal R obtained by the photoelectric conversion element 138, and the sample board circuit 202G. The output amplifier circuit 204G, the AD conversion circuit 206G, the shading correction circuit 208G, and the output delay circuit 210G are used as a signal system for processing the analog image signal G obtained by the photoelectric conversion element 138. The amplification circuit 204B, the AD conversion circuit 206B, the shading correction circuit 208B, and the output delay circuit 210B are used as a signal system for processing the analog image signal G obtained by the photoelectric conversion element 138.

  The photoelectric conversion element 138 is driven by a drive signal from the drive circuit 220, reads a document, and outputs analog image signals R, G, and B to the sample board circuits 202R, 202G, and 202B. That is, the photoelectric conversion element 138 includes a line sensor (not shown) that outputs an analog image signal R, a line sensor (not shown) that outputs an analog line signal G, and a line sensor (not shown) that outputs an analog line signal B. ), And these line sensors represent an analog line signal R representing an R component of N pixels arranged in a straight line in a direction (main scanning direction) crossing the document conveyance direction, an analog line signal G, and The analog line signal B is output to each.

  The sample board circuits 202R, 202G, and 202B sample analog image signals R, G, and B obtained from the photoelectric conversion element 138. The output amplifier circuits 204R, 204G, and 204B amplify the analog image signals R, G, and B to appropriate levels. The AD conversion circuits 206R, 206G, and 206B convert the analog image signals R, G, and B into digital image data R, G, and B, respectively.

  The shading correction circuits 208B, 208G, and 208B have sensitivity variations of the line sensors of the respective colors included in the photoelectric conversion element 138 and the light amount distribution of the optical system with respect to the digital image data R, G, and B from the AD conversion circuits 206R, 206G, and 206B. Make corrections according to the characteristics.

  The output delay circuits 210G and 210B delay the image data G and B output from the shading correction circuits 208G and 208B by delay times corresponding to 4 lines and 8 lines, respectively, and output them as image data in phase with the image data R. .

  The color space conversion circuit 212 converts the image data R input from the shading correction circuit 208R, the image data G input from the output delay circuit 210G, and the image data B input from the output delay circuit 210B into L *, a *. B * color system image data L *, image data a *, and image data b * which are converted and output.

  The image processing circuit 216 is image processing required by the image forming apparatus 10 for the image data L *, the image data a *, and the image data b * output from the color space conversion circuit 212, for example, enlargement / reduction processing, A background removal process, a binarization process, and the like are performed and output to the image forming unit 12 (see FIG. 1).

  The color detection circuit 214 is used as a color detection unit, and the document placed on the platen member 106 using the image data output from the color space conversion circuit 212 is, for example, a single-color document composed of one black color or the like. It detects whether the document is a multicolor document. Details of color detection by the color detection circuit 214 will be described later.

  The CPU 218 is used as a control unit. The CPU 218 forms a single-color image composed of, for example, black toner from the operation panel 302, or is formed of, for example, yellow, magenta, cyan, and black toners. An output relating to selection of whether to form a color image, an output relating to a plurality of operation modes such as setting of image magnification and image quality, and the like are input. Further, the CPU 218 can set an original reading area, which is an area when the original reading apparatus 100 reads an original, or a scanning speed (magnification) at which the original reading apparatus 100 reads an original, monochrome reading or color reading from the operation panel 302. Outputs relating to a plurality of operation modes such as a document conveying method and a plurality of document size settings are input.

  Further, the CPU 218 receives from the open / close sensor 304 a detection result indicating whether the platen cover unit 110 is open or closed with respect to the reading table 104. The CPU 218 receives a detection result from the document sensor 306, and the CPU 218 determines the type and size of the document placed on the platen glass based on the detection result.

  In addition, the CPU 218 sets a driving cycle of the photoelectric conversion element 220 performed by the driving circuit 220, and the sample board circuits 202R, 202G, and 202B, the output amplification circuits 204R, 204G, and 204B, and the AD conversion circuits 206R, 206G, and 206B. The shading correction circuits 208R, 208G, and 208B, the color space conversion circuit 212, the color detection circuit 214, and the image processing circuit 216 are controlled.

  In the above description, an example in which image data is output from the color space conversion circuit 212 to the image processing circuit 216 and image formation is performed by the image forming unit 12 has been described, but instead of output to the image processing circuit 216, Alternatively, together with the output to the image processing circuit 216, the image data may be output from the image processing circuit 216 to an external device such as a personal computer. Further, in place of the output to the image processing circuit 216, or together with the output to the image processing circuit 216, the image data may be stored in a storage unit (not shown) including, for example, a hard disk or a memory.

FIG. 6 is a diagram for explaining an example of detection by the color detection circuit 214 whether a document placed on the platen member 106 is a single color document composed of, for example, one black color or a multicolor document. .
Based on the input image data L *, a *, b *, the color detection circuit 214 divides an area for color detection into a plurality of areas of a predetermined size, as shown in FIG. It is determined whether or not the number of multicolored pixels in the divided areas is equal to or greater than a predetermined number. If the number of pixels in each divided area is equal to or greater than a predetermined number, the divided area is determined to be a multicolor area. On the other hand, if the number of pixels in the divided area and the number of multi-colored pixels is smaller than the predetermined number, it is determined that the divided area is a monochrome area.

  In FIG. 6, the number shown in each divided area is the number of multicolor pixels. In the example shown in FIG. 6, if the number of multicolor pixels in the divided area is 10 or more, It is determined that the divided area is a multicolor area. That is, in the example shown in FIG. 6, the shaded area is an area having 10 multicolor pixels, 20 areas, 13 areas, and 15 areas are multicolored. It is determined that this is the area.

  Further, the color detection circuit 214 determines that the document is a multi-color document when the divided regions and the regions determined to be multi-color are equal to or more than a predetermined number of regions. If the number of areas determined to be multicolor is less than a predetermined number, it is determined that the document is monochrome. In the example shown in FIG. 6, if the number of areas serving as the predetermined threshold is 4, the number of areas determined to be multi-colored is 4, so that the color detection circuit 214 converts the document into multi-color. It is determined that the document is a manuscript.

  The CPU 218 controls which area of the platen member 106 the color detection circuit 214 performs color detection based on the image signal read from. Details of the control will be described later.

FIG. 7 shows a state where an original is placed on the platen member 106, and FIG. 7A shows a state where an A4 size original which is a standard original is placed on the platen member 106. FIG. 7B shows a state in which the non-standard document is placed on the platen member 106.
Here, the standard document refers to a document of a preset size, such as an A4 size document, a B4 size document, or an A3 size document. In the document reading apparatus 100 according to this embodiment, an A4 size document, a B4 size document, and an A3 size document, which are paper sizes stipulated in JIS standards, are handled as standard documents. A B5 size document may be used as a standard document. This paper size is often used for international letter papers, and is used for 8.5 inch x 11 inch (215.9 mm x 279.4 mm) manuscripts called letter sizes and US government official documents. An original of 8.5 inches × 14 inches (215.9 mm × 355.6 mm), which is a paper size and is called a legal size, may be used as a standard document.

  Further, in the document reading apparatus 100 according to this embodiment, it is assumed that the document is placed on the platen member 106 so that the long side of the sheet is in the scanning direction (left and right direction in FIG. 7A). Although the standard size is set, the standard size may be set on the assumption that the short side of the paper is placed in the scanning direction on the platen member 106.

  On the other hand, a non-standard document refers to a document of a size other than a document set as a standard size. For example, when an A4 size document, a B4 size document, and an A3 size document are set as standard sizes, the A5 size document and the legal size document are non-standard size documents. Further, for example, as shown in FIG. 7B, a document in which a part of a standard document is cut out, or a document in which a plurality of documents are shifted from each other and handled as a single document is also an atypical document. It is.

  8 and 9 are flowcharts showing a flow when the CPU 218 controls which color detection circuit 214 performs color detection based on an image signal read from which area of the platen member 106.

As shown in FIG. 8, when the CPU 218 confirms that the document reading area is input in the first step S12, the CPU 218 stores the document reading area input in the next step S14 in a storage unit (not shown). .
The input of the document reading area confirmed in step S12 is performed by the operator operating the operation panel 302. The input of the document reading area is not necessarily an operation required when the document reading apparatus 100 reads the document. When the document reading area is not input, the document reading apparatus 100 displays the size of the document placed on the platen member 106. Is detected by the document sensor 306, and an image of the entire size of the document is read according to the detected size of the document.

  As an example of the case where the operator designates the document reading area, for example, as shown in FIG. In the example shown in FIG. 7B, the size of the non-standard document is larger than the A4 size, which is a standard size document, but smaller than A3, which is the next larger standard size document than the A4 size document. Therefore, the document reading apparatus 100 may detect that the non-standard document is an A4 size document. In this case, the portion of the non-standard document that exceeds the A4 size is not read. In such a case, in order to read the entire atypical document, the operator may designate the A3 size, which is a standard document size larger than the atypical document, as the document reading size. is there.

  Further, the operator may specify the document reading size so that the document reading apparatus 100 reads only a part of the document placed on the platen member 106.

  When reading of the document is started in a state where the document reading area is stored, as shown in FIG. 9, the CPU 218 detects the size of the document placed on the platen member 106 in step S32 as shown in FIG. Let

  In the next step S34, the CPU 218 determines whether or not the platen cover 110 is open based on the output from the open / close sensor 304, and if it is determined that the platen cover 110 is open. In step S36, if it is determined that the platen cover 110 is closed, the process proceeds to step S40.

  In step S36, the CPU 218 compares the document reading area specified in step S12 and stored in step S14 with the size of the document detected in step S32, and the specified and stored document reading area is detected. If the document size is larger than the document size, the process proceeds to step S38. If the designated document reading area is equal to or smaller than the detected document size, the process proceeds to step S40.

In step S38, the CPU 218 controls the color detection circuit 214 to perform color discrimination based on the image signal read from the area detected in S32.
For example, in a state where the platen cover 110 is opened, an atypical document having the shape shown in FIG. 7B is placed on the platen member 106, the current reading size is designated as A3 by the operator, and the document size Is determined to be A4, color determination is performed based on the image signal read from the area of A4 that is the detected document size. That is, the image signal from the area on the surface of the platen member 106 where no document is placed is not used for color discrimination. For this reason, even though the document is a single color image, the document is inserted into a portion of the platen member 106 that is not covered by the document, and the reflected light or the like is misrecognized as a color image. There is no erroneous determination that it is.

  Here, if color discrimination is performed based on the image signal read from the area A3 that is the original reading area, the image signal from the portion of the platen member 106 that is not covered by the original also determines the color of the original. Therefore, there is a possibility that light or the like that is inserted into and reflected from the portion is erroneously recognized as a color image and erroneously determined that a single-color document is a multi-color document.

In step S40, the CPU 218 controls the color detection circuit 214 to perform color discrimination based on the image signal read from the document reading area input in step S12.
If it is determined in step S34 that the platen cover 110 is closed, color determination is performed based on the image signal read from the document reading area in step S40. Therefore, for example, a case where an atypical document having the shape shown in FIG. 7B is placed on the platen member 106, the document reading area is designated as A3 by the operator, and the document size is determined as A4 is taken as an example. Although the area A4 shown in FIG. 7B of the non-standard document is only a single color image, even if there is a multicolor area only in a portion protruding from the area A4, the color detection circuit 214 Then, it is determined that the non-standard document is a multicolor document.

  If it is determined in step S34 that the platen cover 110 is open, and it is determined in step S36 that the document reading area is equal to or smaller than the detected document size, in step S40, Color discrimination is performed based on the image signal read from the document reading area. Therefore, for example, when an atypical document having the shape shown in FIG. 7B is placed on the platen member 106, the document reading area is designated as A4 by the operator, and the document size is determined to be A3, the operator If the area of A4, which is the area designated for reading, is a monochromatic image, even if there is a multicolored area only in the portion that protrudes from the area of A4, the color detection circuit 214 will It is determined that the standard document is a single color document.

  After determining whether the document is a single color image or a multicolor image based on the series of controls described above, the document reading apparatus 100 reads the document based on the determination, and the image processing circuit If the image data processed in 216 is output to the image forming unit 12 (see FIG. 1) and it is determined that the document is a single color, a single color image is formed in the image forming unit 12, and a large number of documents are generated. When it is determined that the image is a color, the image forming unit 12 forms a multicolor image.

  As described above, the present invention can be applied to an original reading apparatus and an image forming apparatus having an original reading apparatus such as a copying machine.

1 is a front view illustrating an image forming apparatus according to an embodiment of the present invention. 1 is a front view showing a document reading apparatus according to an embodiment of the present invention. FIG. 3 is a front view illustrating a state in which an opening / closing cover portion of the document reading apparatus according to the embodiment of the present invention is opened. FIG. 3 is a plan view showing a document table included in the document reading apparatus according to the embodiment of the present invention. 1 is a block diagram illustrating a configuration of a document reading apparatus according to an embodiment of the present invention. FIG. 5 is a diagram illustrating a method for detecting whether a document is multicolored or a single color by the document reading apparatus according to the embodiment of the present invention. FIG. 7A is a plan view showing a state in which an original is placed on an original table included in the original reading apparatus according to the embodiment of the present invention, and FIG. 7B is a plan view showing a state where an atypical document is placed on the document table. 6 is a first flowchart showing an operation of the document reading apparatus according to the embodiment of the present invention. 6 is a second flowchart showing the operation of the document reading apparatus according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming part 100 Document reading apparatus 106 Platen member 110 Platen cover part 130 Reading part 214 Color detection circuit 220 Photoelectric conversion element 302 Operation panel 304 Open / close sensor 306 Document sensor

Claims (3)

A transmission part that transmits light;
A reading unit that irradiates light on a document placed on the transmission unit and reads an image of the document based on light reflected from the document;
An opening / closing part that can be opened and closed so as to cover the transmission part in a closed state;
An open / close detecting means for detecting an open / closed state of the open / close unit;
Document detection means for detecting the size of the document placed on the transmission part;
Color detection means for detecting whether the document is monochromatic or multicolored from an image of a predetermined detection area of the document placed on the transmission unit;
A control unit for controlling the color detection means;
Have
The controller is
When the opening / closing detection unit detects that the opening / closing unit is open, the size of the document detected by the document detection unit and the size of the document reading area where the document is read by the reading unit In comparison, when the size of the document reading area is larger than the size of the document detected by the document detection means , the document is monochrome with the size of the document detected by the document detection means as the detection area. whether to control the color sensing means to sense the multicolor,
When the open / close detection means detects that the opening / closing section is closed, the color detection means is configured to detect whether the original is a single color or multiple colors using the original reading area as the detection area. Control <br/> Document reader.   The control unit is a case where the opening / closing detection unit detects that the opening / closing unit is open, and the size of the document reading area is equal to or smaller than the size of the document detected by the document detection unit. 2. The document reading apparatus according to claim 1, wherein in one case, the color detection unit is controlled to detect whether the document is a single color or multiple colors using the document reading area as the detection area. An original reading apparatus according to claim 1 or 2 ,
An image forming unit that forms an image based on image information read by the document reading device according to claim 1 ,
Image forming apparatus that have a.

Images