JP6740778B2 - Image processing apparatus, image forming apparatus, and program - Google Patents

Description

The present invention relates to an image processing device, an image forming device, and a program.

2. Description of the Related Art Conventionally, in a printing process of offset printing, there is a process called proof printing in which plate data is printed by an electrophotographic machine whose cost per sheet is low and the hue and image quality thereof are confirmed. When performing proof printing with an electrophotographic machine or the like, it is necessary to devise a technique for maintaining the reproducibility of halftone dots, color tones, and the like, and there is a document that discloses a technique for maintaining such reproducibility. In one technique, the area ratio of each halftone dot is corrected in the proof printing process in order to reproduce the dot gain that occurs when the ink is pressed against the printing paper, and the photosensitive material is irradiated with the corrected exposure light amount. By doing so, a latent image is formed (see Patent Document 1).

Generally, the density characteristics of the printer engine are greatly affected by the environment such as temperature and humidity and the temporal change. For this reason, the printer engine adjusts the exposure amount related to image formation and adjusts the engine so as to match the target density characteristic at the timing when the fluctuation of the density characteristic becomes large such as when the printer is activated in the morning or after a large amount of printing. However, if the exposure amount set in the printer engine is changed uniquely for the purpose of reproducing dot gain, color, etc., it will not be possible to reflect the exposure amount setting adjusted by the output environment or aging, etc. There is a problem that reproducibility such as color tone and stability of image quality are affected.

The present invention has been made in view of the above, and is an image processing apparatus, an image forming apparatus, and a program for performing proof printing with high reproducibility, which reflects the setting of the exposure amount adjusted by the output environment, the temporal change, and the like. The purpose is to provide.

In order to solve the above problems and achieve the object, the present invention provides a receiving unit that receives exposure amount information indicating a relationship between an exposure amount and a dot size from an image forming apparatus, and the above receiving unit that receives the exposure amount information. A storage unit for storing the exposure amount information, a reception unit for receiving the proof image data, a resolution conversion unit for converting the proof image data received by the reception unit into an output resolution of the image forming apparatus, and the storage unit. By generating a comparison parameter of the exposure amount to be compared with the value of each pixel position after conversion to the output resolution by normalizing the exposure amount of the stored exposure amount information, the comparison parameter, By transmitting the output data including the dot size determining means for determining the dot size corresponding to the value of each pixel position and the pixel information of the dot size determined by the dot size determining means to the image forming apparatus. And means.

According to the present invention, it is possible to adjust the dot size of each halftone dot of the proof image data based on the setting of the exposure amount adjusted by the output environment or the temporal change. It is possible to obtain a proof printed matter having a high reproducibility while the setting of the exposure amount is changed.

FIG. 1 is a diagram showing an example of the overall configuration of an image generation system including the image processing apparatus according to the first embodiment. FIG. 2 is a diagram illustrating an example of a DFE hardware block. FIG. 3 is a functional block diagram showing an example of main functions related to image processing of DFE. FIG. 4 is a diagram showing an example of exposure amount information. FIG. 5 is an explanatory diagram of processing in the resolution conversion unit. FIG. 6 is an explanatory diagram of processing in the generation unit. FIG. 7 is an explanatory diagram of processing in the dot size determination unit. FIG. 8 is a diagram showing an example of a sequence showing the relationship between the engine adjustment performed by the printer and the update processing of the exposure amount information in the DFE. FIG. 9 is a diagram showing an example of an image processing flow suitable for proof printing executed by the DFE. FIG. 10 is a diagram showing an example of the overall configuration of an image generation system including the image forming apparatus according to the second embodiment. FIG. 11 is a diagram showing an example of the hardware block of the MFP. FIG. 12 is a functional block diagram showing an example of main functions of the MFP. FIG. 13 is a diagram showing an example of an image processing flow suitable for proof printing executed by the MFP.

Hereinafter, embodiments of an image processing apparatus, an image forming apparatus, and a program will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a diagram showing an example of the overall configuration of an image generation system including the image processing apparatus according to the first embodiment. The image generation system 1 illustrated in FIG. 1 includes a computer 10, a DFE (Digital Front End) 20 as an “image processing device”, and a printer 30 as an “image forming device”.

The computer 10 is a computer such as a general-purpose PC (Personal Computer) that transmits image data that is normally printed, such as 8-bit color image data, to the DFE 20. The above 8-bit color image data is an example of “normal image data”. In the present embodiment, in addition to the image data described above, the proof image data Q printed in the proof printing process is read from an external device (for example, an offset printing machine or the like) or a portable storage medium, and the proof image data Q to the DFE 20 is stored. Also send. The proof image data Q is TIFF (Tagged Image File Format) image data with a color depth of 1 bit which has already been subjected to color conversion and halftone dot processing in an external device such as an offset printing machine. In the present embodiment, the proof image data Q will be described as being each plate data of C (Cyan) M (Magenta) Y (Yellow) K (Black).

The DFE 20 transmits various image data to the printer 30 by performing image processing or the like. For example, when the DFE 20 receives 8-bit color image data from the computer 10, the DFE 20 performs data processing such as color conversion and halftone processing on the image data, and outputs the image data to the printer 30. When the DFE 20 receives the proof image data Q from the computer 10, the DFE 20 performs image processing suitable for proof printing on the proof image data Q and outputs the proof image data Q to the printer 30. In the image processing suitable for proof printing, the DFE 20 receives the exposure amount information R from the printer 30 and determines the dot size of the proof image data Q based on the exposure amount information R. The exposure amount information R is information indicating the exposure amount for each dot size of each color of CMYK of the printer 30.

The printer 30 shown as the “image forming apparatus” in the first embodiment is a general-purpose electrophotographic printer having toners of CMYK colors. The printer 30 transmits the exposure amount information R indicating the adjusted exposure amount to the DFE 20 each time the exposure amount related to image formation is adjusted. The printer 30 has a function of adjusting the exposure amount, and adjusts the exposure amount to an optimum value by performing engine adjustment at the timing when the density characteristic of the printer engine greatly changes, such as when the printer is started in the morning or after a large amount of printing. In addition to this, the timing of adjusting the exposure amount includes, for example, after a long time with the power turned on, and after the user gives an instruction for manual adjustment. The printer 30 prints the print data T transmitted from the DFE 20 with the exposure amount adjusted when the print data T is received. The print data T is an example of “output data” that the DFE 20 sends to the printer 30.

With the image processing technique suitable for proof printing described above, the proof image data Q can be printed out in the image data image generation system 1.

Hereinafter, the configuration of the image processing apparatus suitable for proof printing and the processing flow of image processing will be described in more detail.

FIG. 2 is a diagram showing an example of a hardware block of the DFE 20. The DFE 20 illustrated in FIG. 2 includes a CPU (Central Processing Unit) 200, a ROM (Read Only Memory) 201, a RAM (Random Access Memory) 202, a HDD (Hard Disk Drive) 203, a device I/F 204, and a first communication I/F. It has F205 and 2nd communication I/F206, and these are mutually connected by the bus 209. An LCD (Liquid Crystal Display) 207 and a keyboard 208 are connected to the device I/F 204.

The CPU 200 is a central processing unit, and centrally controls the operation of the entire DFE 20. The ROM 201 is a read-only nonvolatile storage medium that stores a fixed program. The RAM 202 is a readable/writable volatile storage medium used as a work area when the CPU 200 processes information. The HDD 203 is a readable/writable non-volatile storage medium that stores various programs and data. The HDD 203 stores programs related to image processing and the like as the above various programs. Further, the HDD 203 is provided with a storage area for storing the exposure amount information R (see FIG. 1) transmitted from the printer 30.

The device I/F 204 is an interface that connects the LCD 207 and the keyboard 208 to the bus 209.

The LCD 207 is a liquid crystal display display for displaying the information generated by the CPU 200.

The keyboard 208 is an input device that notifies the CPU 200 of the key signal of the pressed key.

The first communication I/F 205 is a communication interface such as RS232C or USB (Universal Serial Bus) for communicating with the computer 10.

The second communication I/F 206 is a communication interface such as RS232C or USB for communicating with the printer 30.

Next, the functional configuration of the DFE 20 will be described. The DFE 20 exhibits various functions when the CPU 200 loads various programs such as the ROM 201 and the HDD 203 into the RAM 202 and executes them.

FIG. 3 is a functional block diagram showing an example of main functions related to image processing of the DFE 20. The DFE 20 illustrated in FIG. 3 is a functional unit related to image processing, and includes a first communication control unit 21, a second communication control unit 22, a storage control unit 23, an operation reception unit 24, a display control unit 25, and the like. The image determination unit 26, the proof image processing unit 27, the normal image processing unit 28, the print data transmission instruction unit 29, and the like are included.

The first communication control unit 21 communicates with the computer 10 via the first communication I/F 205 and receives various image data transmitted from the computer 10.

The second communication control unit 22 communicates with the printer 30 via the second communication I/F 206 to receive the exposure amount information R from the printer 30, transmit the print data T to the printer 30, and the like. I do.

The storage control unit 23 accesses the ROM 201, the RAM 202, the HDD 203, and the like, and instructs writing and reading of programs and data according to the access area.

The operation reception unit 24 receives an operation signal (key signal or the like) from the keyboard 208.

The display control unit 25 controls the display on the LCD 207.

The image determination unit 26 determines whether the image data received by the first communication control unit 21 is the image data P for normal printing or the proof image data Q for proof printing.

The proof image processing unit 27 performs image processing suitable for proof printing on the proof image data Q received by the first communication control unit 21. Specifically, the proof image processing unit 27 includes an exposure amount information update instruction unit 27-1, a resolution conversion unit 27-2, a generation unit 27-3, and a dot size determination unit 27-4.

The exposure amount information update instruction unit 27-1 instructs the storage control unit 23 to update the exposure amount information R of the HDD 203 with the latest exposure amount information R received by the second communication control unit 22.

The resolution conversion unit 27-2 converts the proof image data Q into the output resolution of the printer 30.

The generation unit 27-3 normalizes the exposure amount information R of the HDD 203. Specifically, the generation unit 27-3 includes an exposure amount information read instruction unit 27-3A and an exposure amount ratio information generation unit 27-3B. The exposure amount information read instruction unit 27-3A instructs the storage control unit 23 to read the exposure amount information R stored in the HDD 203 for the output paper specified in the output paper type information. The exposure amount information generator 27-3B enables the read exposure amount information R to be compared with the value indicated by each pixel position of the proof image data after resolution conversion by the resolution converter 27-2. Normalize.

The dot size determination unit 27-4 determines the value of each pixel position of the proof image data after resolution conversion and each value of the exposure amount for the dot size indicated by the normalized exposure amount information (as a “comparison parameter”). The conversion parameter is used to determine the dot size at each pixel position in the proof image data after resolution conversion.

The normal image processing unit 28 performs existing image processing on the image data P received by the first communication control unit 21. For example, the normal image processing unit 28 is a processing unit that performs existing image processing, and is a color conversion processing unit 28-1, a total amount control unit 28-2, a gamma conversion unit 28-3, and a halftone processing unit 28-. 4 and so on.

The color conversion processing unit 28-1 converts the 8-bit color image data P from various input formats into CMYK 8-bit color image data.

The total amount control unit 28-2 adjusts the toner amount for the pixels whose total toner amount of CMYK exceeds the control value according to the total amount control value of the printer 30.

The gamma conversion unit 28-3 corrects the CMYK density characteristics according to the density characteristics of the printer 30.

The halftone processing unit 28-4 performs halftone dot processing to generate image data that matches the color depth of the printer 30.

The print data transmission instructing unit 29 instructs the second communication control unit 22 to transmit the print data T (see FIG. 1) to the printer 30. The print data T is image data generated by image processing by either the proof image processing unit 27 or the normal image processing unit 28 is stored in the data unit, and header information such as print settings is added.

FIG. 4 is a diagram showing an example of the exposure amount information R (see FIG. 1). FIG. 4 shows the exposure amount information of each of the three types of paper as an example. The exposure amount information R1 shown in FIG. 4A is the exposure amount information of plain paper. The exposure amount information R2 shown in FIG. 4B is the exposure amount information of glossy paper. The exposure amount information R3 shown in FIG. 4C is the exposure amount information of the matte paper.

Each of the exposure amount information R1 to R3 has dot size information indicating the dot size of the printer 30 and CMYK information indicating the toner color (corresponding to the process color) of the printer as information for classifying the exposure amount. In this example, the dot size information has three types of 3/3 dots, 2/3 dots, and 1/3 dots, and of these, 3/3 dots represent the largest dot size.

In each of the exposure amount information R1 to R3, a value indicating the exposure amount is set at a position corresponding to any of the dot size information and any of the CMYK information. For example, in the exposure amount information R1 of the plain paper in FIG. 4A, the value "5." indicating the exposure amount is provided at the position corresponding to "3/3 dots" of the dot size information and "K" of the CMYK information. 49 (unit is nanosecond “ns” indicating exposure time)” is set. These values differ depending on the engine characteristics of the printer 30 and are appropriately updated according to the timing of engine adjustment.

Next, each process of the proof image processing unit 27 will be described in detail. Here, as an example of the proof image data Q, plate data of process color “M” having a color depth of 1 bit and a resolution of 2400 dpi is used. A printer having a color depth of 2 bits and a resolution of 1200 dpi is used as the printer 30 that outputs the proof image.

FIG. 5 is an explanatory diagram of processing in the resolution conversion unit 27-2. In the plate data d1 shown in FIG. 5, each of the rectangular areas in the matrix is defined as one pixel, and each pixel is classified according to the pixel value. In this example, since the color depth of the printing plate data d1 is 1 bit, each pixel takes either a pixel value "1" at which dots are formed or a pixel value "0" at which dots are not formed. In the printing plate data d1 shown in FIG. 5, pixels in which dots are formed are indicated by hatched portions, and pixels in which dots are not formed are indicated by blanks.

In this example, the resolution converter 27-2 converts the plate data d1 from 2400 dpi to 1200 dpi of the printer 30 to a low resolution. Therefore, here, the low resolution data of 1200 dpi is obtained by converting the pixel value of 4 pixels into the information indicating the ratio of 1 pixel in units of 4 pixels of the plate data d1 (that is, "unit pixel area"). It shows what obtains d2. The rectangular frame X0 shown in FIG. 5 shows one processing unit (unit pixel area consisting of 4 pixels).

For the sake of explanation, the plate data d1 shown in FIG. 5 is provided with dot forming portions E1 to E4 at four locations, each of which has a different number of pixels forming a dot. The dot forming unit E1 has all four pixels among the four pixels that are the processing unit as a dot forming unit. The dot forming section E2 has 3 pixels as a dot forming section. The dot forming section E3 has two pixels as a dot forming section. The dot forming section E4 has one pixel as a dot forming section.

Here, as an example, the maximum dot size is set to "1", and the value (pixel occupancy ratio) obtained by dividing this "1" by the number of pixels of the dot forming unit is set as the coordinate (pixel position) indicated by one pixel of the conversion destination. Set. That is, the resolution is reduced by assigning the average value of the pixel values of the dot forming portion in the original area (area of 4 pixels in this example) to 1 pixel. An arrow line X1 shown in FIG. 5 represents the coordinate E14, which is the conversion destination of the dot forming portion E4, as an example of the conversion destination by an arrow.

In the case of this example, the dot forming unit E1 has all four pixels of the four pixels that are the processing unit as the dot forming unit, and therefore, “1” is set to the coordinate E11 of one pixel of the conversion destination of the four pixels. Since the dot forming portion E2 has 3 pixels as the dot forming portion, “0.75” is set to the coordinate E12 of the conversion destination pixel of 4 pixels including the dot forming portion E2. Since the dot forming unit E3 has two pixels as the dot forming unit, “0.50” is set to the coordinate E13 of one pixel of the conversion destination of the four pixels including the dot forming unit E3. Since the dot forming unit E4 has one pixel as a dot forming unit, "0.25" is set to the coordinate E14 of one pixel of the conversion destination of the four pixels including the dot forming unit E4. For each of the four pixels that do not include the other dot forming portions, "0" is set to the coordinate of each conversion destination pixel.

FIG. 6 is an explanatory diagram of processing in the generation unit 27-3. The exposure amount information R10 shown in FIG. 6A is an example of the exposure amount information of plain paper among the three types of paper. Note that the exposure amount information R10 shown in FIG. 6A and the exposure amount information R1 shown in FIG. 4 show different values because they are updated due to changes over time.

Here, as an example, the process of normalizing the exposure amount value of each dot size in each CMYK color so that all the exposure amount values of 3/3 dots, which is the maximum dot size in each CMYK color, are aligned to “1” Show. Although it has been stated that all the exposure amount values of 3/3 dots are set to “1”, this “1” corresponds to each coordinate value of the low resolution data d2 after the conversion processing of the resolution conversion unit 27-2. The comparison is made possible, and corresponds to "1" set to the maximum dot size in resolution conversion, that is, the upper limit of the pixel occupancy ratio.

The generation unit 27-3 multiplies the value of the exposure amount of each dot size by a value such that the value of the exposure amount of 3/3 dots, which is the maximum dot size, becomes the upper limit value of the pixel occupancy ratio for each CMYK color. match. Here, as an example, the value of the exposure amount of each dot size is divided by the value of the exposure amount of 3/3 dots, which is the maximum dot size, and the effective figures after the decimal point are rounded or truncated. Since the value of each pixel of the low-resolution data d2 after resolution conversion is up to two digits after the decimal point, the figure below shows the significant figures up to two digits after the decimal point.

For example, in the “M” color of the exposure amount information R10, the value of the exposure amount of 3/3 dots is set to “0.90”. Therefore, the generation unit 27-3 determines that the exposure amount value “0.30” for the 1/3 dot of the “M” color, the exposure amount value “0.60” for the 2/3 dot of the “M” color, The value "0.90" of the exposure amount of 3/3 dots of the color "M" is divided by the value "0.90" of the exposure amount of the maximum dot size of the color "M", and the value is a value up to a significant figure. Ask for. For other colors, the values up to significant figures are calculated by the same procedure.

As another example, in the “Y” color of the exposure amount information R10, the value of the exposure amount of 3/3 dots is set to “0.80”. Therefore, the generation unit 27-3 determines the exposure amount value of each dot size, that is, the exposure amount value “0.20” of 1/3 dot of “Y” color and the exposure amount of 2/3 dot of “Y” color. The amount value “0.50” and the exposure amount value “0.80” of the 3/3 dots of the “Y” color are respectively set to the exposure amount value “0.80” of the maximum dot size of the “Y” color. Divide and calculate up to significant figures as the value.

The exposure amount information R100 shown in FIG. 6B shows the exposure amount information after normalization of the exposure amount information R10 of FIG. 6A. As is clear from the value set in the exposure amount information R100, all the exposure amount values of 3/3 dots of each color of CMYK are converted into "1". Further, by this normalization, the value of the exposure amount of each dot size of each color of CMYK is converted into a ratio having a maximum value of “1” (comparable to the “pixel occupancy ratio”), and the dot of each color of CMYK It can be used as a conversion parameter for size.

FIG. 7 is an explanatory diagram of processing in the dot size determination unit 27-4. FIG. 7 shows the state of the set values of the coordinates indicating each pixel of the low resolution data d2 before and after the dot size determined by the dot size determination unit 27-4.

The dot size determination unit 27-4 sets, for each coordinate indicating each pixel of the low resolution data d2, the set value and the conversion parameter of the corresponding color of the exposure amount information R100 after normalization (see FIG. 6B). By comparing, the dot size of each coordinate is determined.

Here, since the plate data of “M” color is taken as an example, the dot size determination unit 27-4 compares it with the conversion parameter of “M” color of the exposure amount information R100, and the conversion parameter for each dot size. The dot size is determined based on the set value under the following conditions, for example. For the "M" color, the one with a value of 0 to 0.32 is determined to have no dot, and for the one with a value of 0.33 to 1.00, the dot size having a closer value is determined. .. Here, the dots of 0 to 0.32 are set to have no dots, but those of the range of 0 to 0.32 are smaller than the minimum dot size of the printer 30. This is because it cannot be expressed. Note that the conditions shown here are examples, and may be modified as appropriate. For example, only pixels having a value of “1” may be determined to have 3/3 dots, and some pixels may be modified so as to include a pixel having no range.

The converted image data d3 shown in FIG. 7 is image data in which the corresponding pixels are represented in gradation by the dot size determined by the dot size determination unit 27-4. The correspondence between the low resolution data d2 and the converted image data d3 is as follows. Since the value of the coordinate E11 of the low resolution data d2 is “1”, the gradation information indicating 3/3 dots is set in the corresponding pixel E21 of the converted image data d3.

Since the pixel value E12 of the low resolution data d2 is “0.75”, the gradation information indicating 2/3 dots is set in the corresponding pixel E22 of the converted image data d3.

Further, since the pixel value E13 of the low resolution data d2 is “0.50”, the gradation information indicating 2/3 dots is set in the corresponding pixel E23 of the converted image data d3.

Further, since the pixel value E14 of the low resolution data d2 has a value of "0.25", gradation information indicating no dot is set in the corresponding pixel E24 of the converted image data d3.

As for the other pixels of the converted image data d3, since the pixel value of the low resolution data d2 is “0”, gradation information indicating no dot is set.

Next, the processing of the image generation system 1 will be described. First, a process in which the DFE 20 receives the exposure amount information R (see FIG. 1) from the printer 30 will be described. The printer 30 adjusts the exposure amount by performing engine adjustment when the printer is started, after a large amount of printing, after being left for a long time while the power is on, or when the user manually instructs the adjustment.

FIG. 8 is a diagram showing an example of a sequence showing a relationship between engine adjustment performed by the printer 30 and update processing of the exposure amount information R in the DFE 20. The printer 30 first executes an engine adjustment process to determine an optimum exposure amount (S1). Specifically, the printer 30 approaches the target density characteristic while adjusting the exposure amount related to image formation to the optimum solution at each moment, and the exposure amount when the target density characteristic is reached is the exposure amount to be used thereafter. Save as the value of. The printer 30 determines the value of the exposure amount for each type of paper, each color of CMYK, and each dot size.

Then, the printer 30 transmits the value of the exposure amount determined for each type of paper, each color of CMYK, and each dot size, that is, the exposure amount information R to the DFE 20 (S2). The printer 30 performs such a transmission process of step S2 each time the engine adjustment process is executed.

Upon receiving the exposure amount information R from the printer 30, the DFE 20 updates the exposure amount information R of the HDD 203 with the received exposure amount information R (S3).

FIG. 9 is a diagram showing an example of an image processing flow suitable for proof printing executed by the CPU 200 of the DFE 20. First, the CPU 200 (exposure amount information update instruction unit 27-1) acquires the latest exposure amount information R (see FIG. 3) transmitted from the printer 30 from the second communication control unit 22, and the exposure amount of the HDD 203. The storage controller 23 is instructed to update the information R (see FIG. 3) (S10).

Subsequently, the CPU 200 (image determination unit 26) acquires image data for which a print instruction has been issued from the first communication control unit 21, and the image data is image data P for normal printing (see FIG. 3) or proof. It is determined whether the image data is Q (see FIG. 3) (S11).

Hereinafter, processing for proof printing will be described. First, the CPU 200 (resolution conversion unit 27-2) converts the proof image data Q into the output resolution of the printer 30 (S12).

Subsequently, the CPU 200 (exposure amount information read instruction unit 27-3A) instructs the storage control unit 23 to obtain the latest exposure amount information R stored in the HDD 203 (S13).

Subsequently, the CPU 200 (exposure amount ratio information generation unit 27-3B) normalizes the exposure amount information R acquired in step S13 (S14).

Subsequently, the CPU 200 (dot size determination unit 27-4) compares the value indicated by each pixel position of the proof image data after resolution conversion with the conversion parameter indicated by the normalized exposure amount information, and after the resolution conversion. The dot size at each pixel position of the proof image data is determined (S15).

Then, the CPU 200 (print data transmission instruction unit 29) instructs the second communication control unit 22 to transmit the print data T (see FIG. 3) to the printer 30 (S16). The print data T is obtained by storing image data generated by the image processing up to step S15 in the data section and adding header information such as print settings.

In the first embodiment, the second communication I/F 206 and the second communication control unit 22 mainly correspond to “receiving means”. Further, the exposure amount information update instruction unit 27-1, the storage control unit 23, and the HDD 203 mainly correspond to “storage means”. In addition, the first communication I/F 205, the first communication control unit 21, and the image determination unit 26 mainly correspond to “accepting means”. The resolution conversion unit 27-2 mainly corresponds to “resolution conversion means”. In addition, the generating unit 27-3 mainly corresponds to “generating means”. The dot size determination unit 27-4 mainly corresponds to “dot size determination means”. Further, the print data transmission instruction unit 29, the second communication control unit 22, and the second communication I/F 206 mainly correspond to “transmission means”. Further, the image determination unit 26 mainly corresponds to “determination means”. Further, the normal image processing unit 28 mainly corresponds to “normal image processing means”.

In the first embodiment, the system configuration is shown in which the DFE 20 receives the exposure amount information R transmitted every time the engine is adjusted by the printer 30, but when the DFE 20 performs image processing of the proof image data Q. Alternatively, the system configuration may be modified to obtain the latest exposure amount information from the printer 30.

(Second embodiment)
FIG. 10 is a diagram showing an example of the overall configuration of an image generation system including the image forming apparatus according to the second embodiment. The image generation system 2 illustrated in FIG. 10 includes a computer 10 and an MFP (MultiFunction Peripheral) 40 as an “image forming apparatus”. In the present embodiment, it is assumed that the computer 10 and the MFP 40 are connected via a network such as a LAN (Local Area Network) or a VPN (Virtual Private Network). The computer 10 is the same as that shown in the first embodiment except that it communicates with the MFP 40 via the network. Therefore, the configuration of the MFP 40 will be described in detail below.

The MFP 40 is an MFP equipped with the function of the DFE 20 (see FIG. 3) shown in the first embodiment.

FIG. 11 is a diagram showing an example of a hardware block of the MFP 40. The MFP 40 illustrated in FIG. 11 includes a CPU 400, an ASIC (Application Specific Integrated Circuit) 401, a system memory 402 including a ROM 402a and a RAM 402b, an interface 403 including an SD memory card slot 403a, a USB interface 403b, and a network interface 403c. It has an auxiliary storage device 404, a touch display 405, an engine 406, and a scanner 407.

The CPU 400 performs various processes in cooperation with various control programs stored in advance in the ROM 402a or the auxiliary storage device 404, using a predetermined area of the RAM 402b as a work area, and centrally controls the operation of the entire MFP 40.

The ASIC 401 is an IC (Integrated Circuit) for image processing applications having a hardware element for image processing, and has a function as a bridge that connects the CPU 400 and each unit.

The ROM 402a is a read-only memory that stores fixed programs and fixed data. The RAM 402b is a volatile memory that can be written and read freely and is used for developing programs and data or for drawing on a printer.

The interface 403 is an interface that detachably connects the own device and an external device. An SD memory card slot 403a shown as an example in FIG. 11 is detachably connected to an SD (registered trademark) memory card as an external storage device. The USB interface 403b detachably connects a USB flash memory as an external storage device.

The interface 403 also includes an interface for connecting the own device to the network. The network interface 403c shown in FIG. 4 is a network card or the like, and connects itself to the network.

Note that, in the present embodiment, an SD memory card, a USB flash memory, etc. are illustrated as the external storage device, but the external storage device is not limited to these.

The auxiliary storage device 404 has a storage medium that is magnetically, electrically, or optically written or read. For example, an HDD or the like has a magnetic recording medium. The auxiliary storage device 404 rewritably stores programs related to various controls of the MFP 40 (including programs related to image processing suitable for proof printing) and setting information such as device capability information. The auxiliary storage device 404 also stores image data input by the scanner 407, image data input via the interface 403, and the like.

The touch display display 405 is an interface for the user to operate the MFP 40 interactively, and includes a display device such as a liquid crystal display and an input device including a touch panel, a key switch group, and the like. Under the control of the CPU 400, the touch display display 405 displays the state of the operation and settings of the MFP 40 and the operation method on the screen of the display device. Further, when the touch display 405 detects an input by the user through the touch panel or the key switch group, the touch display 405 outputs the input information to the CPU 400.

The engine 406 is a printer engine, and is, for example, a monochrome plotter, a one-drum color plotter, a four-drum color plotter, or the like. The engine 406 includes an image processing portion of proof image data in addition to a so-called engine portion such as a plotter.

The scanner 407 includes a line sensor including a CCD (Charge Coupled Device) photoelectric conversion element, an A/D converter that converts an analog read signal into a digital signal, and a drive circuit thereof.

Next, the functional configuration of the MFP 40 will be described. The MFP 40 exerts various functions by the CPU 400 loading various programs such as the ROM 402a and the auxiliary storage device 404 into the RAM 402b and executing them.

FIG. 12 is a functional block diagram showing an example of main functions of the MFP 40. The MFP 40 illustrated in FIG. 12 serves as a functional unit related to image processing, including a communication control unit 41, a storage control unit 42, an operation reception unit 43, a display control unit 44, an engine adjustment unit 45, an image determination unit 46, and the like. A proof image processing unit 47, a normal image processing unit 48, a print execution unit 49, and the like are included.

The communication control unit 41 communicates with the computer 10 via the network interface 223c and receives various image data transmitted from the computer 10.

The storage control unit 42 accesses the ROM 402a, the RAM 402b, the auxiliary storage device 404, and the like, and instructs writing and reading of programs and data according to the access area.

The operation receiving unit 43 receives an operation signal (key signal or the like) from the touch panel of the touch display 405, a key switch group, or the like.

The display control unit 44 controls display on the display device of the touch display display 405.

The engine adjusting unit 45 adjusts the exposure amount related to the image formation of the engine 406 to the target density characteristic while adjusting the optimum solution at each moment, and the exposure amount when the target density characteristic is adjusted is adjusted to the latest exposure value. The quantity value is saved in the auxiliary storage device 404.

The image determination unit 46 determines whether the image data received by the communication control unit 41 is the image data P for normal printing or the proof image data Q for proof printing.

The proof image processing unit 47 has a resolution conversion unit 47-1, a generation unit 47-2, and a dot size determination unit 47-3. The resolution conversion unit 47-1 converts the proof image data Q into the output resolution of this device.

The generation unit 47-2 normalizes the exposure amount information R updated by the most recently adjusted exposure amount value in the auxiliary storage device 404. Note that the normalization method is the same as that in the first embodiment, so description thereof will be omitted.

The dot size determination unit 47-3 determines the dot size at each pixel position of the proof image data after resolution conversion. Note that the method of determining the dot size is the same as that in the first embodiment, so description thereof will be omitted.

The normal image processing unit 48 corresponds to the normal image processing unit 28 (see FIG. 3) and performs existing image processing on the image data P received by the communication control unit 41. The description above is omitted because it is the same as the description of the first embodiment.

The print execution unit 49 controls the engine 406 to print the print data T.

FIG. 13 is a diagram showing an example of an image processing flow suitable for proof printing executed by the CPU 400 of the MFP 40. First, the CPU 400 (engine adjustment unit 45) executes the engine adjustment process at a predetermined timing, and updates the exposure amount information R of the auxiliary storage device 404 with the latest exposure amount information R obtained by the execution. (S20).

The subsequent processing from step S21 to step S25 corresponds to the processing from step S11 (see FIG. 9) to step S15 (see FIG. 9) in the DFE 20 shown in the first embodiment, and thus the description thereof is omitted here. To do.

Following step S25, the CPU 400 (print execution unit 49) controls the engine 406 to print the print data T (S26).

In the second embodiment, the engine adjusting unit 45 mainly corresponds to “adjusting means”. The print execution unit 49 and the engine 406 mainly correspond to “image forming means”.

Some or all of the functional units shown in the respective embodiments may be configured by hardware such as ASIC.

In each embodiment, since the resolution conversion from 2400 dpi to 1200 dpi is taken as an example, the processing unit (unit pixel area) of the conversion source of resolution conversion is 4 pixels. However, this processing unit corresponds to the resolution of the proof image data. You may change suitably according to the output resolution of a printer or MFP.

In addition, as an example, the color depth of the printer or MFP is set to 2 bits, and three types of dot sizes of 1/3 dot, 2/3 dot, and 3/3 dot are shown. It may be increased or decreased depending on the color depth of the MFP.

As described above, in each embodiment and each modification, the dot size of each halftone dot of the proof image data can be adjusted based on the setting of the exposure amount adjusted according to the output environment and the temporal change. Therefore, the setting of the exposure amount adjusted according to the output environment and changes over time will be reflected, and it is possible to obtain the proof printed matter with high reproducibility such as hue and stability of image quality in the highlight area. Play.

Further, by using the exposure amount information corresponding to the paper type, it becomes possible to deal with different fixing conditions depending on the output paper type on the printer or MFP side.

Further, by replacing the pixel value with the numerical value of the pixel occupancy ratio at the time of resolution conversion, it becomes possible to apply the conversion parameter to the proof image data of arbitrary resolution.

The program executed in each embodiment and each modified example is provided by being pre-installed in a memory unit such as a ROM or HDD, but is not limited to this. The program executed in each embodiment and each modification may be recorded in a computer-readable recording medium such as DFE or MFP and provided as a computer program product. For example, even if a file in an installable format or an executable format is recorded on a recording medium such as a flexible disk, a CD-R, a DVD (Digital Versatile Disk), a Blu-ray disk (registered trademark), or a semiconductor memory, the file is provided. Good.

In addition, the program executed in each embodiment and each modification may be stored in a computer connected to a network such as the Internet and may be provided by being downloaded via the network. The program executed in each embodiment and each modification may be provided or distributed via a network such as the Internet.

20 DFE
21 1st communication control part 22 2nd communication control part 23 Storage control part 24 Operation acceptance part 25 Display control part 26 Image determination part 27 Proof image processing part 27-1 Exposure amount information update instruction part 27-2 Resolution conversion Unit 27-3 generation unit 27-3A exposure amount information read instruction unit 27-3B exposure amount ratio information generation unit 27-4 dot size determination unit 28 normal image processing unit 28-1 color conversion processing unit 28-2 total amount control unit 28 -3 Gamma conversion unit 28-4 Halftone processing unit 29 Print data transmission instruction unit P image data Q proof image data R exposure amount information T print data

JP, 2006-030277, A

Claims (10)

Receiving means for receiving exposure amount information indicating the relationship between the exposure amount and the dot size from the image forming apparatus,
Storage means for storing the exposure amount information received by the receiving means,
Acceptance means for accepting proof image data,
Resolution conversion means for converting the proof image data received by the reception means into an output resolution of the image forming apparatus;
Generating means for generating an exposure amount comparison parameter to be compared with the value of each pixel position after conversion to the output resolution by normalizing the exposure amount of the exposure amount information stored by the storage means;
Dot size determining means for determining a dot size corresponding to the value of each pixel position by comparison with the comparison parameter,
Transmitting means for transmitting output data including pixel information of the dot size determined by the dot size determining means to the image forming apparatus;
An image processing apparatus comprising: The receiving unit receives information indicating the updated exposure amount from the image forming apparatus as the exposure amount information each time the exposure amount is updated in the image forming apparatus.
The image processing apparatus according to claim 1, wherein: The receiving means receives the exposure amount information of each color of toner,
The storage means stores the exposure amount information of each color of the toner received by the receiving means,
The receiving means receives proof image data for each process color as the proof image data,
The generation unit normalizes the exposure amount of the exposure amount information stored in the storage unit for each of the process colors to compare the exposure amount with the value of each pixel position after conversion to the output resolution. Generate a comparison parameter for each process color,
The dot size determining means determines the dot size corresponding to the value of each pixel position by comparing with the comparison parameter corresponding to the process color of the proof image data received by the receiving means, among the comparison parameters.
The image processing apparatus according to claim 1, wherein: The receiving unit receives the exposure amount information of each type of paper,
The storage means stores the exposure amount information of each type of the paper received by the receiving means,
The reception means receives the proof image data and information indicating a type of output paper,
The generation unit normalizes the exposure amount of the exposure amount information stored in the storage unit for each type of the output paper, and compares it with the value of each pixel position after conversion to the output resolution. An exposure amount comparison parameter is generated for each type of the output paper,
The dot size determining means determines the dot size corresponding to the value of each pixel position by comparing with the comparison parameter corresponding to the information indicating the type of the output paper received by the receiving means among the comparison parameters. ,
The image processing apparatus according to claim 1, wherein: The resolution conversion unit associates, as the value of each pixel position after the conversion, a pixel occupancy ratio that represents a ratio of the number of pixels whose pixel value occupies 1 to the total number of pixels of the unit pixel region of the conversion source
In the normalization, the generation unit multiplies the value of the exposure amount of the maximum dot size of the exposure amount information, which is the upper limit value of the pixel occupation ratio, by the value of the exposure amount of each dot size.
The image processing apparatus according to claim 1, wherein: The dot size determining means determines the dot size corresponding to the value of each pixel position on the basis of the information indicating the ratio of each dot size using the information indicating the ratio of each dot size obtained by the multiplication as the comparison parameter. decide,
The image processing apparatus according to claim 5, wherein Furthermore,
The reception means has a determination means for determining whether the image data is normal image data or proof image data,
A normal image processing means for performing image processing on the normal image data when the reception means determines that the image data is normal image data;
The transmitting unit transmits the image data image-processed by the normal image processing unit to the image forming apparatus,
The image processing apparatus according to claim 1, wherein: Adjusting means for adjusting the exposure amount of the device itself,
Storage means for storing exposure amount information indicating the relationship between the exposure amount and the dot size most recently adjusted by the adjusting means,
Acceptance means for accepting proof image data,
Resolution conversion means for converting the proof image data received by the reception means into an output resolution of the device itself,
Generating means for generating an exposure amount comparison parameter to be compared with the value of each pixel position after conversion to the output resolution by normalizing the exposure amount of the exposure amount information stored by the storage means;
Dot size determining means for determining a dot size corresponding to the value of each pixel position by comparison with the comparison parameter,
An image forming unit that forms an image of the dot size determined by the dot size determining unit,
An image forming apparatus comprising: A computer of an image processing apparatus having a storage unit,
Receiving means for receiving exposure amount information indicating the relationship between the exposure amount and the dot size from the image forming apparatus,
Storage means for storing the exposure amount information received by the receiving means in the storage part;
Acceptance means for accepting proof image data,
Resolution conversion means for converting the proof image data received by the reception means into an output resolution of the image forming apparatus;
By normalizing the exposure amount of the exposure amount information stored in the storage unit, generating means for generating a comparison parameter of the exposure amount to be compared with the value of each pixel position after conversion to the output resolution,
Dot size determining means for determining a dot size corresponding to the value of each pixel position by comparison with the comparison parameter,
Transmitting means for transmitting output data including pixel information of the dot size determined by the dot size determining means to the image forming apparatus;
And a program to make it work. A computer of an image forming apparatus that has a function of adjusting the exposure amount and stores the exposure amount information indicating the relationship between the most recently adjusted exposure amount and the dot size in the storage means ,
Acceptance means for accepting proof image data,
Resolution conversion means for converting the proof image data received by the reception means into an output resolution of the device itself,
Generating means for generating an exposure amount comparison parameter to be compared with the value of each pixel position after conversion to the output resolution by normalizing the exposure amount of the exposure amount information stored by the storage means;
Dot size determining means for determining a dot size corresponding to the value of each pixel position by comparison with the comparison parameter,
An image formation instructing means for instructing formation of an image of the dot size determined by the dot size determining means,
And a program to make it work.

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