JP4956490B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus capable of storing read image data in a storage unit.

  In an image forming apparatus such as a digital multi-function peripheral, when reproducing an original image, first, reflected light obtained by scanning while irradiating light exposed from a slit is used as image information for a photoelectric conversion element (CCD). : Charge Coupled Device) receives the light and converts the voltage, and the obtained analog image information is digitally converted to read the original image.

  Then, the digital signal is optically converted, and an electrostatic latent image corresponding to the original image is formed on a uniformly electrostatically charged photoreceptor. Thereafter, the electrostatic latent image formed on the photoreceptor is developed with toner (also referred to as “developer”). The toner image on the photosensitive member is transferred onto the recording paper by static electricity having a reverse polarity, and the toner image transferred onto the recording paper is heated and pressed to be fixed.

  In addition, when a document image read from a scanner is output as a copy, in order to prevent the capacity of data stored in a storage device provided in the apparatus from becoming too large and to enhance security, The obtained image data is temporarily stored in a memory or HDD, but is erased after copying. For this reason, the previously read image data cannot be reused, and the same document must be copied again.

  For this reason, in Patent Document 1, attribute data is detected from document image data read by a scanner or image data sent from a PC (personal computer) or a facsimile machine, and the attribute data and image data are temporarily stored in a memory or HDD ( Spool to hard disk device.

  The image data in the spooled memory or HDD is read out, and processing such as print processing, file transmission, and FAX transmission is performed, so that the operation is not complicated, the original is not deteriorated, the original is easily removed, and the optimum An image processing apparatus having a multi-function function capable of obtaining a high image quality is provided.

Further, in Patent Document 2, conversion for file output and conversion for print output are performed on input image data obtained by one-time image reading, and the image data for file output and the image data for print output are converted. By outputting both, the operation efficiency is improved with a simple operation.
JP 2001-223828 A JP 2001-339606 A

However, in Patent Document 1, since the read image data and attribute data are stored in the HDD, there is a problem that the accumulated data amount presses the storage capacity of the HDD.
Here, the read image data is the final processing result (for example, color information, resolution, and area separation) processed for output. To copy again, various images and image quality are changed. Cannot be added, and there is a problem that the amount of information is insufficient.
Further, in Patent Document 2, since the image data after the image processing in the former stage and the latter stage is stored, there is a problem that the image data cannot be used for optimal output by other image forming apparatuses.

  The present invention has been made in consideration of the above-described circumstances, and image data obtained by performing only the preceding image processing on a document that the user has decided to use in the future based on the user's selection. An object of the present invention is to provide an image forming apparatus that can be stored in a storage unit.

  In order to solve the above-described problems, an image forming apparatus of the present invention includes an input device that reads an image, an image output device that outputs an image based on the read (color) image data, and the read image data. A first image processing unit that extracts image features and adds information necessary for the second image processing unit and adjusts image quality to a reusable image; and processing results of the first image processing unit A second image processing unit that performs image processing corresponding to the mode specified by the user and halftone image processing that matches the engine state, and whether or not to save the progress of the processing of the first image processing unit The first image processing unit, and when the setting unit is set to store the progress of the processing, the first image processing unit and the processing result of the first image processing unit Is a preset It is intended to save the part.

Here, the image processing of the first image processing unit includes A / D conversion processing, shading correction processing, and input tone correction processing.
The processing result temporarily stored in the first image processing unit is erased after a predetermined time.

  The first image processing unit may be further subjected to a region separation process, further may be subjected to a color conversion process, and further, when the setting unit is set to store the progress of the process The intermediate process and the processing result may be transmitted to a preset external device.

According to the present invention, it is possible to store, in the storage unit, image data obtained by performing the previous image processing on a document that the user has determined to use in the future based on the user's selection.
By using the image data stored in the storage unit, the operation of reading the document many times can be omitted.

  Hereinafter, preferred embodiments according to an image forming apparatus of the present invention will be described with reference to the drawings.

<Configuration of electrophotographic process>
FIG. 1 is a diagram illustrating a configuration of an image forming apparatus according to the present embodiment. As shown in FIG. 1, an image forming apparatus 50 forms multicolor and single color images on a predetermined sheet in accordance with image data from the outside, and includes an exposure unit 1, a developing device 2, and a photosensitive drum. 3 is an electrophotographic color image forming apparatus including a charger 5, a cleaner unit 4, an intermediate transfer belt unit 8, a fixing unit 12, a paper transport path S, a paper feed tray 10, a paper discharge tray 15, and the like. .

  The image data handled in the image forming apparatus 50 corresponds to a color image using each color of black (K or BK), cyan (C), magenta (M), and yellow (Y). Accordingly, the image forming apparatus 50 includes four image stations corresponding to the respective colors.

  That is, the developing device 2 (2a, 2b, 2c, 2d), the photosensitive drum 3 (3a, 3b, 3c, 3d), the charger 5 (5a, 5b, 5c, 5d), the cleaner unit 4 (4a, 4b, 4c and 4d) are provided for each color, and four types of latent images corresponding to the respective colors are formed on the peripheral surface of each photosensitive drum 3. Here, it is assumed that a letter at the end of the code corresponds to a for black, b for cyan, c for magenta, and d for yellow.

  Hereinafter, the configuration of one image station will be described on behalf of the four image stations. Since other image stations have the same configuration, the alphabetical character at the end of the code is omitted.

  The charger 5 is a charging unit for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential. As the charging means, in addition to the contact type roller type, a brush type charger or a charger type charger may be used.

The exposure unit 1 is an exposure unit that selectively exposes the surface of a charged photoreceptor. As the exposure means, in addition to the laser scanning unit (LSU) shown in FIG. 1, a writing head in which light emitting elements such as EL and LEDs are arranged in an array may be used.
The exposure unit 1 has a laser irradiation unit and a polygon mirror, and reflects and deflects the laser beam L from the laser irradiation unit to the rotating polygon mirror to scan the surface of the photosensitive member.

  The laser beam L is modulated according to image data generated by reading a document, or modulated according to image data generated by an external computer. By scanning and exposing the photosensitive drum 3 charged with the laser beam L modulated by the image data, an image of an electric potential (electrostatic latent image) corresponding to the image data is formed on the surface of the photosensitive drum 3. Is done.

The developing device 2 develops (develops) the electrostatic latent images formed on the respective photosensitive drums 3 with toners of any one of K, C, M, and Y colors.
The cleaner unit 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after being developed and transferred as described later.

An intermediate transfer belt unit 8 is disposed above the photosensitive drum 3. The intermediate transfer belt unit 8 includes an intermediate transfer belt 7, an intermediate transfer belt driving roller 8-1, an intermediate transfer belt tension mechanism 8-3, an intermediate transfer belt driven roller 8-2, and intermediate transfer rollers 6 (6a, 6b, 6c, 6d) and an intermediate transfer belt cleaning unit 9.
The intermediate transfer belt drive roller 8-1, the intermediate transfer belt tension mechanism 8-3, the intermediate transfer roller 6, the intermediate transfer belt driven roller 8-2, etc. stretch the intermediate transfer belt 7 and rotate it in the direction of arrow B. .

  The intermediate transfer roller 6 is rotatably supported by the intermediate transfer roller mounting portion of the intermediate transfer belt tension mechanism 8-3 of the intermediate transfer belt unit 8. A transfer bias voltage for transferring the toner image formed on the photosensitive drum 3 onto the intermediate transfer belt 7 is applied to the intermediate transfer roller 6.

  The intermediate transfer belt 7 is provided so as to be in contact with the photosensitive drum 3 for each color. The toner images of the respective colors formed on the surface of the photosensitive drum 3 are sequentially transferred to the intermediate transfer belt 7 by the transfer bias voltage applied to the intermediate transfer roller 6. As a result, a color toner image (multi-color toner image) is transferred onto the intermediate transfer belt 7 in a multilayer form. The intermediate transfer belt 7 is formed with an endless film having a thickness of about 50 μm to 120 μm.

  As described above, the intermediate transfer roller 6 is in contact with the back side of the intermediate transfer belt 7 and is a transfer unit that transfers the toner image from the photosensitive drum 3 to the intermediate transfer belt 7. A transfer bias voltage having a voltage of about several hundred volts (a voltage having a polarity (+) opposite to the charging polarity (−) of toner) is applied to the intermediate transfer roller 6 in order to transfer the toner image.

  The intermediate transfer roller 6 is a roller whose base is a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). With this conductive elastic material, a substantially uniform voltage can be applied to the intermediate transfer belt. In the present embodiment, a transfer roller is used as the transfer unit, but a brush-like transfer electrode (transfer brush) can also be brought into contact with the back side of the intermediate transfer belt 7 as the transfer unit.

The toner image transferred to the intermediate transfer belt 7 moves to the secondary transfer device 11 in which the secondary transfer roller 11e is disposed as the intermediate transfer belt 7 rotates.
The intermediate transfer belt 7 and the secondary transfer roller 11e are pressed against each other so as to have a predetermined nip width. The secondary transfer roller 11e is applied with a transfer bias voltage for transferring a toner image onto a sheet to be described later (a high voltage having a polarity (+) opposite to the toner charging polarity (-)). Or, conversely, a transfer bias voltage of about several hundred volts from the intermediate transfer belt drive roller 8-1 to the secondary transfer roller 11e (voltage having the same polarity (−) as the toner charging polarity (−)) is applied. You may apply.

  One of the secondary transfer roller 11e and the intermediate transfer belt drive roller 8-1 is made of a hard material (metal, etc.), and the other is a soft material (elastic rubber roller, foaming resin roller, etc.) on the surface of the core metal. Is a covered elastic roller. As a result, a nip having a predetermined width is constantly obtained.

  Due to the contact with the surface of the photosensitive drum 3, toner adheres to the intermediate transfer belt 7 in addition to the area where the image is transferred to the sheet. Further, there is toner remaining on the intermediate transfer belt 7 without being transferred onto the sheet by the secondary transfer roller 11e. These toners can cause toner color mixing in the next step. For this reason, an intermediate transfer belt cleaning unit 9 is provided, and the toner on the intermediate transfer belt 7 is removed and collected.

  The intermediate transfer belt cleaning unit 9 includes a cleaning blade as a cleaning member, and an end portion of the cleaning blade comes into contact with the intermediate transfer belt 7 to remove toner. At the portion where the intermediate transfer belt cleaning unit 9 contacts, the intermediate transfer belt 7 is supported by the intermediate transfer belt driven roller 8-2 from the back side.

  The paper feed tray 10 is a tray for accumulating sheets used for image formation. The paper feed tray 10 is provided below the exposure unit 1 of the image forming apparatus 50. In addition, a paper discharge tray 15 is provided on the upper portion of the image forming apparatus 50. Printed sheets are discharged face-down on the paper discharge tray 15 and accumulated.

<Description of color image processing>
Next, color image processing included in the color image forming apparatus will be described.
As illustrated in FIG. 2, the color image processing unit 100 includes a color image input unit 111, a color image processing unit 100, and a color image output unit 141.

  The color image input unit 111 includes, for example, a scanner unit, and a reflected light image from a document is converted into an RGB signal (R: red, G: green, B: blue) analog signal as a CCD (Charge Coupled Device). Read on.

  The color image output unit 141 performs predetermined image processing in the color image processing unit 100 and outputs the result. The color image output unit 141 can also be applied to an output unit using a method other than the above-described electrophotographic method, for example, an ink jet recording method or a sublimation recording method.

  The color image processing unit 100 includes an A / D conversion unit 121, a shading correction unit 122, an input tone correction unit 123, a region separation processing unit 131, a color conversion processing unit 132, a black generation / under color removal unit 133, and spatial filter processing. Section 134, output gradation correction (output γ correction) section 135, and gradation reproduction process (halftone generation) section 136.

In the color image processing unit 100, the analog signal of the document image read by the color image input unit 111 is first converted into a digital signal by an A / D (analog / digital) conversion unit 121. Then, the shading correction unit 122 performs shading correction for removing various distortions generated in the illumination system, imaging system, and photographing system of the color image output apparatus.
After the shading correction processing, the input tone correction unit 123 performs image quality adjustment processing such as contrast only when the user wants to arbitrarily adjust the output image.

  Next, the region separation processing unit 131 separates each pixel into a character region, a halftone dot region, or a photograph region, and based on the separation result, an region identification signal indicating which region the pixel belongs to. The data is output to the black generation / under color removal unit 133, the spatial filter processing unit 134, and the gradation reproduction processing unit 136, respectively.

Here, the region separation method will be described below.
First, the halftone dot determination unit obtains an average value (Dave) of signal levels for the central nine pixels in the block, and binarizes each pixel in the block using the average value. Further, the maximum pixel signal level (Dmax) and the minimum pixel signal level (Dmin) are also obtained at the same time.

  Next, the halftone dot area is used to distinguish the area from the halftone dot area by utilizing the fact that the fluctuation of the image signal in the small area is large and the density is higher than the background. In the main scanning and sub-scanning directions, the number of change points from 0 to 1 is obtained, and the change points from 1 to 0 are obtained as KH and KV, respectively, and both exceed the threshold values compared to the threshold values TH and TV. In such a case, the halftone dot area is set.

In order to prevent erroneous determination with the background, B1 and B2 are set as threshold values.
Dmax-Dave> B1, Dave-Dmin> B2, KH> TH, and KV> TV
In this case, it is determined as a halftone dot region, and in other cases, it is determined as a non-halftone dot region.

  Next, the character edge determination unit obtains a density difference between the target pixel and its neighboring pixels in a 3 × 3 pixel block centered on the target pixel, and any one of them is determined from the threshold value THc (or THm or THy). If it is larger, it is determined as a character edge region, and if it is smaller than the threshold THc (or THm or THy), it is determined as a photo region.

  In the color conversion processing unit 132, CMY (C: cyan, M: magenta, Y: yellow) color including unnecessary absorption components for realizing fidelity based on the data sent from the region separation processing unit 131. A process for removing color turbidity based on the spectral characteristics of the material is performed.

  Next, the black generation / under color removal unit 133 subtracts the black signal generated by the black generation from the original CMY signal and the black generation for generating the black (K) signal from the CMY three-color signal after the color conversion process. A lower color removal process for generating a new CMY signal is performed, and the CMY three-color signal is converted into a CMYK four-color signal.

  Next, the spatial filter processing unit 134 performs a spatial filter process using a digital filter, and corrects the spatial frequency characteristics so as to prevent blurring of the output image and deterioration of graininess.

  Then, the output tone correction unit 135 performs output tone correction processing for converting a signal such as a density signal into a halftone dot area ratio that is a characteristic value of image output, and the tone reproduction processing unit 136 further performs output tone correction processing. A gradation reproduction process, that is, a halftone process, is performed in which the image is finally divided into pixels and each gradation is reproduced.

  Further, the image region extracted as a black character or in some cases a color character by the region separation processing unit 131 is a high frequency band in the sharpness enhancement processing in the spatial filter processing unit 134 in order to improve the reproducibility of the black character or the color character. The amount of frequency enhancement is increased. At the same time, in the halftone generation process (gradation reproduction processing unit 136), a binarization process or a multi-value process on a high resolution screen suitable for high frequency reproduction is selected.

  On the other hand, with respect to the region determined as a halftone dot by the region separation processing unit 131, the spatial filter processing unit 134 performs low-pass filter processing for removing the input halftone dot component. At the same time, in the halftone generation process (gradation reproduction processing unit 136), binarization or multi-value processing is performed on the screen with an emphasis on gradation reproducibility.

The image data subjected to the above-described processes is temporarily stored in a first storage unit (not shown), read at a predetermined timing, and input to the color image output unit 141.
The above processing is controlled by a CPU (Central Processing Unit).

<Hardware configuration>
FIG. 3 is a block diagram illustrating a hardware configuration of the image forming apparatus 50.
As shown in FIG. 3, the image forming apparatus 50 includes a CPU 72, a ROM (Read Only Memory) 74, a RAM (Random Access Memory) 76, a first HDD (Hard Disk Drive) 78, a second HDD 80, and an operation unit 90. The image processing unit 100, the scanner unit 110, the output unit 140, the FAX unit 200, and the transmission / reception unit 300. Here, the first HDD 78 and the second HDD may be the same storage device or separate storage devices.

A common BUS line 38L is connected to the CPU 72, and a ROM 74, RAM 76, HDD 78, HDD 80, etc. are connected to the common BUS line 38L.
The CPU 72 realizes the function of the image processing unit 100 by executing a computer program for realizing the image processing of the present embodiment stored in the ROM 74 or the HDD 78.

The scanner unit 110 executes the function of the color image input unit 111 described above.
The first image processing unit 120 included in the image processing unit 100 performs first image processing on the document image read by the scanner unit 110 (second image processing is performed by extracting image features from the read image data). The image processing unit assigns necessary information and performs image quality adjustment to a reusable image, and temporarily stores the processing result in the first HDD 78. The data temporarily stored in the first HDD 78 is deleted after a predetermined time when output is performed.

The operation unit 90 includes a selection key 91 that is a feature of the present invention.
The selection key 91 is used to set whether or not to save the processing result of the first image processing unit 120. The selection key 91 is used to specify a storage destination recording device and a transfer destination of an external device.
If the selection key 91 is pressed before reading the document, the first image processing unit 120 displays the processing result of the first image processing and the progress of the processing in the second set as the storage destination. The program is stored in the HDD 80, and the process is terminated without printing.

Further, the second image processing unit 130 included in the image processing unit 100 performs second image processing (designated by the user based on the processing result of the first image processing unit) on the image data temporarily stored in the HDD 78. Image processing corresponding to the selected mode and halftone image processing in accordance with the engine state).
The output unit 140 executes the function of the color image output unit 141 described above, and outputs the result processed by the image processing unit 100 to a recording sheet.

<Process flow>
Next, the processing procedure of the image forming apparatus according to the present embodiment will be described with reference to the flowchart of FIG.
First, when copying, the user operates the operation unit 90 to input copy conditions, set a selection key 91 for a document that is determined to be used in the future, and press a copy start key (START key). Push. The selection key 91 is used to set whether or not to save the processing result of the first image processing unit 120. The selection key 91 also designates a storage destination recording device and a transfer destination external device.

When the copy start key is pressed, the scanner unit 110 reads the document as an RGB signal according to the set copy conditions (step S1).
First image processing is performed on the RGB signals of the read document (image characteristics are extracted from the read image data, information necessary for the second image processing unit is added, and the image is reusable) Image processing for performing image quality adjustment) (step S2), and the processing result is temporarily stored in the first storage means (first HDD 78) (step S3). The processing result stored in the first storage means is automatically deleted when a predetermined time comes after output.

  If the selection key 91 has been set by the user (YES in step S4), the result of the first image processing is stored and stored in the second storage means (second HDD 80) (step S5), and the processing is terminated. .

  On the other hand, when the selection key 91 is not set (NO in step S4), the second image processing (based on the processing result of the first image processing unit) is performed on the image data stored in the first storage unit (first HDD 78). The image processing corresponding to the mode designated by the user and the halftone image processing in accordance with the engine state are performed (step S6), and the image data subjected to the second image processing by the output unit 140 is used on a sheet or the like. Output (step S6), the process ends.

As described above, at the time of copying, based on the user's selection, the image data read from the document that is determined to be used in the future is subjected to the previous image processing, and the processing result and the progress of the processing are stored in the storage unit ( (Second storage means).
As a result, it is not necessary to read the original with a scanner, so that the work time for the second and subsequent copies can be shortened. Further, since no extra image data is stored, the storage capacity of the storage device can be reduced.

Further, when the result of the first image processing is stored, it may be stored in the second HDD 78 after performing the region separation processing or further after performing the color conversion processing. As a result, the image data that has been subjected to the color conversion process fitted to the image forming apparatus can be obtained, so that the process can be omitted when the image is output later, and the processing time can be shortened.
Further, the image data may be stored in accordance with the resolution of the output unit, or the spatial filter processing conditions may be changed and stored.

  Further, in the above description, the processing result obtained by performing the first image processing on the read image data and the progress in the middle are stored in the second HDD 80. However, if accumulated, the data amount will press the storage capacity. Therefore, the data stored in the second HDD 80 may be transmitted to the external device via the transmission / reception unit 300. As a result, the accumulated data amount of the second HDD 80 can be suppressed, and an image can be directly output from an external device.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and corrections can be made without departing from the scope of the present invention.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment. It is a block diagram which shows the function structure of a color image process part. 1 is a block diagram illustrating a hardware configuration of an image forming apparatus according to an embodiment. 6 is a flowchart illustrating a processing procedure of the image forming apparatus according to the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 50 ... Image forming apparatus, 1 ... Exposure unit, 2 ... Developing device, 3 ... Photosensitive drum, 4 ... Cleaner unit, 5 ... Charger, 6 ... Intermediate transfer roller, 7 ... Intermediate transfer belt, 8 ... Intermediate transfer belt unit 8-1: Intermediate transfer belt drive roller, 8-2: Intermediate transfer belt driven roller, 8-3: Intermediate transfer belt tension mechanism, 9 ... Intermediate transfer belt cleaning unit, 10 ... Paper feed tray, 11 ... Secondary transfer 11e ... secondary transfer roller, 12 ... fixing unit, 15 ... paper discharge tray, 38L ... common BUS line, 72 ... CPU, 74 ... ROM, 76 ... RAM, 78 ... first HDD, 80 ... second HDD, 90 ... operation section, 91 ... selection key, 100 ... (color) image processing section, 110 ... scanner section (image reading section), 111 ... color image input section, 120 ... first image processing section 121: A / D conversion unit, 122: Shading correction unit, 123: Input tone correction unit, 130: Second image processing unit, 131: Area separation processing unit, 132: Color conversion processing unit, 133: Black generation / bottom Color removal unit 134 ... Spatial filter processing unit 135 ... Output tone correction unit 136 ... Tone reproduction processing unit 140 ... Output unit 141 ... Color image output unit 200 ... FAX unit 300 ... Transmission / reception unit

Claims (5)

An input device that reads an image, an image output device that outputs an image based on the read image data, and information necessary for the second image processing unit to extract image features from the read image data A first image processing unit that performs image quality adjustment to a reusable image that is given and an image processing corresponding to a mode designated by the user and an engine state based on a processing result of the first image processing unit In an image forming apparatus having a second image processing unit that performs halftone image processing ,
Comprising a setting unit that sets whether or not to save the progress of processing of the first image processing unit, if the save-progress in the processing by the setting unit has been set, the processing of the first image processing unit Is stored in a storage unit set in advance, and if the setting is not set, the processing result of the first image processing unit is processed by the second image processing unit and output . An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein the image forming apparatus handles a color image.   The image forming apparatus according to claim 1, wherein the first image processing unit further performs a region separation process.   4. The image forming apparatus according to claim 1, wherein the first image processing unit further performs a color conversion process. 5. 5. The image forming apparatus according to claim 1, wherein the first image processing unit is in the process of the first image processing unit when the setting unit stores the progress of the process. An image forming apparatus that transmits a progress and a processing result to a preset external device.

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