JP2009100060A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus for optically capturing an original image of an original placed on an original platen, which can normally detect the original image without using an original retaining cover. <P>SOLUTION: The image forming apparatus is configured so that a light-emitting section 3 emits light of a specific wavelength for irradiation toward the original platen 15 where an original is placed, a light-receiving section 5 receives the light from the original platen 15, converts the light into an electric signal and outputs the converted signal, a judging section 7 judges a reflection region where the emitted light is reflected on the basis of an output signal from the light-receiving section 5, and an image processing section 9 processes an image in the judged reflection region. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an improvement in an image forming apparatus such as a multi function peripheral (MFP) that optically captures a document image by placing the document on a document table.

  In general, in an image processing apparatus, for example, a multi-function peripheral, a sheet to be a document is placed on a document platen and a pressing cover is placed on the platen. Is detected, and a toner image formed based on this image is transferred and fixed on a printing paper for printing.

In this case, if you print on printing paper larger than the original size of the original placed on the platen,
Even if the presser cover is placed on the original, the light on the surface of the presser cover that protrudes from the original and the reflected light due to subtle shades are detected as an image, and unnecessary lines and stripes appear around the original, resulting in print quality. It is easy to lower.

  When copying a thick original like a book, light entering from the outside is easily detected even if the pressing cover is placed on the original, and the same inconvenience is likely to occur.

  Therefore, for example, an information processing apparatus disclosed in Japanese Patent Publication No. 2-55788 (Patent Document 1) has been proposed.

In this patent document 1, a fluorescent paint is applied to a pressing surface of a document in a document pressing cover, and a document area is detected by identifying a difference between the color of the document and the color of the fluorescent paint. This is to prevent unsightly blackening.
Japanese Patent Publication No. 2-55788

  However, in the above-mentioned patent document 1, since the document is detected by identifying the reflected light of the document pressing cover, there is a concern that it cannot be normally detected depending on the state of the cover such as deterioration of the paint applied to the pressing cover. When copying a thick original as described above, light entering from the outside is detected, and there still remains a problem that the above-described problem cannot be solved.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of detecting an image area of a document without a document pressing cover and obtaining a good print quality. To do.

  In order to solve such problems, an image forming apparatus according to the present invention includes a light emitting unit that emits and emits light of a specific wavelength toward a document table on which a document is placed, and receives light from the document table side. A light receiving unit that converts the input light of the specific wavelength into an electrical signal, a determination unit that determines the reflection region of the emitted light from the output signal of the light receiving unit, and an image detection process from the output signal of the determined reflection region An image processing unit.

  And in the image forming apparatus of this invention, the said light emission part can be comprised so that monochromatic light may be light-emitted as the specific wavelength.

  In the image forming apparatus of the present invention, a configuration in which the discrimination unit discriminates the reflection area from an output signal exceeding a predetermined level is also possible.

  In such an image forming apparatus according to the present invention, when light of a specific wavelength is emitted from the light emitting unit toward the document table on which the document is placed, the light from the document table side is received by the light receiving unit. Converts and outputs an electrical signal corresponding to light of a specific wavelength, and determines the reflected region of the emitted light from the output signal of the light receiving unit, so that the reflected light reflected by the original is detected and other external light is ignored However, even without the document pressing cover, it is possible to detect the image of the document, and it is easy to obtain good print quality.

  In the image forming apparatus of the present invention, when the light emitting unit emits monochromatic light having a specific wavelength, it is easy to detect an image of a document, and a light receiving member that converts reflected light into an electrical signal is available at a low cost. easy.

  Further, in the image forming apparatus of the present invention, when the discrimination unit discriminates the reflection area from the output signal exceeding a predetermined level, the discrimination of the reflection area is easy and the image detection of the document is easily accelerated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an image forming apparatus according to the present invention.

  In the figure, an image forming apparatus A according to the present invention is, for example, a multi-function machine formed with a drive unit 1, a light emitting unit 3, a light receiving unit 5, a discrimination unit 7, an image processing unit 9, a printing unit 11, and a control unit 13. is there. In addition, the image forming apparatus A includes other components such as a storage unit, a display unit, and an operation unit, but the description and illustration are omitted because they are not the main part of the present invention.

  As shown in FIG. 2, for example, a plurality of light emitting units 3 are arranged in a line so as to cross the short side direction (main scanning direction) of the transparent original table 15 in a rectangular area slightly larger than, for example, A3 of the paper size. It consists of a diode.

  The light emitting unit 3 emits monochromatic light, particularly blue monochromatic light with a specific wavelength, for example, a wavelength of about 450 nanometers (nm) from the back side of the document table 15 by a driving signal from a known driving unit 1 not shown in FIG. It has a function of emitting light toward the table 15.

  In general, as shown in FIG. 3, the spectral characteristics of light are bell-shaped spectral characteristics (dotted line), incandescent light is rising to the right (dashed line), and fluorescent lamps are combined with multiple wavelengths (dashed line). For example, the light emitting unit 3 is configured to strongly emit blue monochromatic light having a specific wavelength excluding the wavelength of the fluorescent lamp.

  The light receiving unit 5 is a line sensor arranged in a line in the vicinity of the light emitting unit 3, receives light from the document table 15, converts input light of the specific wavelength into an electric signal, and responds to the light amount. It has a function of outputting an electrical signal of a different level to the determination unit 7.

  As the light receiving unit 5, for example, an RGB sensor (light receiving diode) that detects only the specific wavelength and converts it into an electrical signal can be used.

  The light emitting unit 3 and the light receiving unit 5 can be moved together with a predetermined pitch in the long side direction (sub-scanning direction) on the back surface of the document table 15 by a displacement mechanism (not shown). There is also known a configuration in which light is received at a position away from the light-emitting unit 3 via (not shown).

  The discriminating unit 7 has a function of discriminating an area where an output signal exceeding a predetermined level from the light receiving unit 5 is obtained as a reflection area.

  In other words, since the light receiving unit 5 outputs an electric signal having a level corresponding to the light amount of the specific wavelength, the determination unit 7 determines a region having a high detection level as a reflection region from the document and outputs it to the image processing unit 9. And has a function of ignoring output signals in other regions.

  Depending on the image layout such as the layout of characters and figures in the document, the level of detection of individual parts in the reflection area may be high or low. Therefore, it is possible to determine a non-reflective area outside the document by receiving sunlight or artificial illumination light.

  The image processing unit 9 acquires the presence / absence of image data from the detection level of each minimum unit area in the reflection area, and generates electronic image data as a print job by filtering the image data for each document. The image data for each page is output to the printing unit 11 or stored in the storage unit.

  Under the control of the control unit 13, the printing unit 11 converts image data from the paper feeding unit for setting a printing paper, a toner cassette in which toner is stored, and the image processing unit 9 or the storage unit into print image image data. A known color or monochrome printing engine having a transfer fixing unit that develops and develops toner with toner from a toner cassette and transfers and fixes the printing paper onto a printing paper, and a paper discharge unit that discharges the printing paper on which an image is transferred and fixed. is there.

  As described above, since the light emitting unit 3 emits monochromatic light having a specific wavelength, when image data based on the output signal from the light receiving unit 5 is printed by the printing unit 11, a monochrome image is likely to be obtained.

  The control unit 13 includes a CPU and a ROM that stores an operation program for the CPU. The control unit 13 includes the driving unit 1, the light emitting unit 3, the light receiving unit 5, the determining unit 7, the image processing unit 9, and the printing unit. 11 and the like, as well as a function unit (not shown) of the multifunction peripheral.

  The driving unit 1, the light emitting unit 3, the light receiving unit 5, the determining unit 7, and the image processing unit 9 may be referred to as an image reading unit.

  Next, the operation of the image forming apparatus according to the present invention will be briefly described with reference to the flowchart of FIG.

  When an instruction to start reading the document is given, the light emitting unit 3 emits light to the document on the document table 15 in step S1, and the light receiving unit 5 detects incident light including the reflected light. In step S2, the determining unit Whether or not the reflected light from the document is determined by the output signal level based on the received light 7.

  If the reflected light is from the document and step S2 is YES, the image processing unit 9 processes the received light as image data in step S3 and proceeds to step S5, where step S2 is not reflected from the document. If NO, in step S4, the image processing unit 9 ignores the received light and proceeds to step S5.

  In step S5, the image processing unit 9 generates electronic image data as a print job by filtering the image data acquired in step S5, and the document reading is terminated in step S6.

  These procedures are executed by the driving unit 1, the light emitting unit 3, the light receiving unit 5, the discriminating unit 7, the image processing unit 9, and the like described above mainly by the control unit 13 according to the operation program.

  As described above, the image forming apparatus according to the present invention receives the light from the light emitting unit 3 that emits and emits light of a specific wavelength toward the document table 15 on which the document is placed, and the light from the document table 15 side. The light receiving unit 5 that converts and outputs an electrical signal corresponding to the input light of the specific wavelength, the determination unit 7 that determines the reflection region of the emitted light from the output signal of the light reception unit 5, and the image in the determined reflection region And an image processing unit 9 that performs detection processing.

  For this reason, even if there is no document holding cover, it is easy to detect the reflected light by the light emitted from the light emitting part and the other reflected light, and to detect an image in the image area of the document. Even when a certain original is copied, it is difficult to detect light entering from the outside, and it is possible to prevent the edge of the copy paper from being unsightly and dark and easy to obtain good print quality.

  In addition, since the light emitting unit 3 emits monochromatic light, it is easy to accurately detect an image in the image area of the document, and a detection member that detects reflected light by the light emitted from the light emitting unit 3 is inexpensive and easily available.

  Furthermore, since the discrimination unit 7 discriminates the reflection area from the output signal exceeding a predetermined level, the discrimination process is easy and fast, and the image forming speed of the original is easily increased.

  When the image forming apparatus of the present invention is implemented in a multifunction machine, a copying machine, a scanner, or the like provided with a conventional document pressing cover, the configuration is simplified because the document pressing cover is unnecessary.

  Furthermore, as described above, since the image data based on the monochromatic light of the specific wavelength of the light emitting unit 3 is easily printed by the printing unit 11, the present invention is suitable for an image forming apparatus for monochrome printing.

1 is a block diagram showing an embodiment of an image forming apparatus according to the present invention. 1 is a schematic diagram illustrating an outline of a document table in an image forming apparatus according to the present invention. It is a figure which shows the spectral characteristic of light. 6 is a flowchart illustrating an operation of the image forming apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive part 3 Light-emitting part 5 Light-receiving part 7 Discriminating part 9 Image processing part 11 Printing part 13 Control part 15 Document base A Image forming apparatus

Claims (3)

A light emitting unit that emits and emits light of a specific wavelength toward the document table on which the document is placed;
A light receiving unit that receives light from the document table side and converts the input light of the specific wavelength into an electrical signal;
A discriminating unit for discriminating a reflection region of the emitted light from an output signal of the light receiving unit;
An image processing unit for detecting and processing an image from the output signal of the determined reflection area;
An image forming apparatus comprising: The image forming apparatus according to claim 1, wherein the light emitting unit emits monochromatic light having the specific wavelength. The image forming apparatus according to claim 1, wherein the determination unit determines the reflection region from the output signal exceeding a predetermined level.

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