JP2019168565A - Image forming device - Google Patents

Abstract

To provide an image forming device with which it is possible to print with high productivity while controlling a fixing device in accordance with a carried toner amount, even when detection of a carried toner amount takes time.SOLUTION: The image forming device comprises: a reception unit for receiving print data; a conversion unit for converting the print data received by the reception unit into image data; an image formation unit for forming an image on recording paper on the basis of the image data converted by the conversion unit; a fixation unit for fixing the image formed on recording paper by the image formation unit; and a control unit for analyzing the image data converted by the conversion unit and determining the fixing temperature of the fixation unit on the basis of the result of analysis. The control unit compares the estimated toner use amount of print data with the minimum concentration integrated value of filled region of a prescribed size, and when the estimated toner use amount is smaller, determines a fixation temperature without analyzing the image data.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an image forming apparatus that thermally fixes a toner image formed by an electrophotographic method onto a recording sheet.

  In recent years, there has been an increasing market demand for energy saving and high speed for OA devices such as printers and copiers. In an image forming apparatus that thermally fixes a toner image formed by an electrophotographic method onto a recording sheet, it is important to improve the power consumption and fixing speed of the fixing device in order to achieve these required performances.

  Usually, the fixing temperature and fixing speed of the fixing device are determined in consideration of the maximum amount of color material that can be placed on the recording paper in order to obtain stable fixing properties. In a full-color copying machine, an image is formed by superimposing a plurality of color materials such as CMYK (cyan, magenta, yellow, black) and the like. Tend to increase). Further, since the toner application amount is closely related to an area where the image forming apparatus can express a color (hereinafter referred to as a color reproduction area), a sufficient toner application amount is required to maintain high image quality.

  However, when the toner application amount of the entire image exceeds a predetermined value, or when toner is applied so as to fill a continuous area (hereinafter referred to as “detection area”) of a predetermined size determined by the characteristics of the fixing device, A high fixing temperature or a long fixing time is required. In the former case, power consumption increases, and in the latter case, the printing speed decreases. Therefore, the fixing temperature and fixing speed of the fixing device are changed according to the maximum amount of applied toner in the image.

  In addition, there is a problem that high-speed printing cannot be performed in the case of an image forming apparatus that takes time to perform image processing and toner application amount detection itself. When the detection of the amount of applied toner is not completed within a predetermined time, there is one that controls the fixing temperature adjustment with a provisional value (see Patent Document 1).

Japanese Patent Laying-Open No. 2015-206984

  However, the above-described Patent Document 1 has a problem that high-speed printing cannot be performed for the processing time because the toner application amount detection process is performed even for an image with a small toner application amount such as a text document. In an image forming apparatus that realizes detection of the amount of applied toner by software processing, a decrease in printing speed appears significantly.

  In order to solve the above-described problems, the image forming apparatus of the present invention has an estimated value of the total amount of toner necessary for printing an image (hereinafter referred to as “toner estimated usage amount”) and a minimum amount of applied toner in the detection area. Are compared to determine whether the detection area can be filled. If the detection area cannot be filled, skipping the toner application amount detection process enables high-productivity printing.

  According to the present invention, since detection of the applied toner amount of image data with a small applied toner amount is omitted, it is possible to prevent a decrease in printing speed.

1 is a diagram illustrating a system configuration diagram of an image forming apparatus. It is a block diagram which shows the structure of an image process part. FIG. 6 is a block diagram showing a configuration of fixing temperature control by image analysis. 1 is a diagram illustrating a configuration of a printer of an image forming apparatus. FIG. 6 is a diagram illustrating a relationship between a toner loading value and a fixing temperature. 6 is a flowchart illustrating toner applied amount detection processing. FIG. 6 is a diagram illustrating toner applied amount detection processing. FIG. 6 is a diagram illustrating toner estimated usage amount calculation processing. 6 is a flowchart illustrating a toner estimated usage amount calculation process. It is a figure explaining an image analysis implementation control process. It is a flowchart which shows an image analysis implementation control process. It is a flowchart which shows an image analysis implementation control process. It is a flowchart which shows an image analysis implementation control process. It is a figure which shows the effect of image analysis implementation judgment. It is a figure explaining the image analysis implementation control processing in 2nd Embodiment. It is a flowchart which shows the image analysis implementation control processing in 2nd Embodiment. It is a figure which shows the effect of the image analysis execution judgment in this embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
(System configuration)
The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a system configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus is an electrophotographic color or monochrome image forming apparatus using toner such as a digital electrophotographic copying machine, a laser printer, and a facsimile.

  The image forming apparatus 0100 includes a controller 0101 and external modules (an operation unit 0121, a printer 0122, an external storage device 0123, and an external device 0124). The controller 0101 includes a ROM 0102, a CPU 0103, a RAM 0104, and an image processing unit 0105. The CPU 0103 is a central processing unit (processor) that performs control of the entire apparatus, arithmetic processing, and the like, and performs each process described below based on a program stored in the ROM 0102.

  A ROM 0102 is a read-only memory, and is a storage area for a system activation program, a program for controlling the printer engine, character data, character code information, and the like. The RAM 0104 is a random access memory and is a data storage area with no usage restrictions. The RAM 0104 is used as a storage area for font data additionally registered by downloading, or as an execution area for programs and data for various processes. The RAM 0104 can also be used as a data storage area for received image files. An image processing unit 0105 performs image data generation processing.

  The operation unit 0121 performs display using, for example, a liquid crystal or the like, and is used to display the setting state of the apparatus, the current internal processing of the apparatus, and the error state. It is also used to change or reset print settings. The printer 0122 is a part that controls each device (such as a fixing device) of the printer engine. The external storage device 0123 is a storage medium (for example, an SD card), and is used for spooling data, storing programs, information files, image data, and the like, and working areas.

  The controller 0101 further includes various interfaces (I / F) and a system bus 0111. The operation unit I / F 1012 is connected to the operation unit 0121. A printer I / F 0113 performs data supply control and the like with the printer 0122. A network I / F 0114 connects this apparatus to an external apparatus 0124 via a network (for example, a LAN). The device I / F 0115 is connected to the external storage device 0123. The system bus 0111 serves as a data path between the above structural elements.

  The printer 0122 has an image forming unit 0125, a paper transport unit 0126, a fixing device unit 0127, and a temperature detection unit 0128. The image paper unit 0125 forms a toner image of data supplied from the printer I / F 0113 on the transfer belt. A paper transport unit 0126 transports the paper to the toner image position on the transfer belt. The fixing device unit 0127 fixes the toner image on the sheet by heating and pressurizing to a desired temperature using the temperature detecting unit 0128 that is in contact.

(Configuration of image processing unit)
FIG. 2 is a block diagram showing the configuration of the image processing unit in the present embodiment. The DMA unit 0201 receives image data from hardware connected to the signal line 0111 and outputs the data to the estimated toner usage calculation unit 0202 based on a value set in advance in the DMA unit. The estimated toner usage calculation unit 0202 calculates the estimated toner usage, outputs the estimated toner usage 0204, and outputs to the JBIG unit 0211, the JPEG unit 0212, the scaling unit 0213, the RIP unit 0214, and the binarization unit 0215. Output image data.

  The JBIG unit 0211 decompresses JBIG-compressed image data input from the DMA unit 0201 and outputs the image data to the DMA unit 0203. Alternatively, JBIG compression is performed on the bitmap format image data input from the DMA unit 0201 and output to the DMA unit 0203.

  The JPEG unit 0212 performs JPEG decompression on the JPEG-compressed image data input from the DMA unit 0201 and outputs it to the DMA unit 0203. Alternatively, JPEG compression is performed on the bitmap format image data input from the DMA unit 0201 and output to the DMA unit 0203.

  The scaling unit 0213 enlarges or reduces the bitmap format image data input from the DMA unit 0201 based on a value set in advance in the scaling unit 0213, and outputs the image data to the DMA unit 0203.

  For the intermediate data generated from the PDL data input from the RIP unit 0214 and the DMA unit 0201, based on the values set in the RIP unit 0214 in advance, bitmap format image data is generated and output to the DMA unit 0203 To do. The binarization unit 0215 applies the binary bitmap format image data to the multi-value bitmap format image data input from the DMA unit 0201 based on the values set in the binarization unit 0215 in advance. Generate and output to the DMA unit 0203.

  The DMA unit 0203 inputs data from the JBIG unit 0211, the JPEG unit 0212 unit, the scaling unit 0213, the RIP unit 0214, and the binarization unit 0215, and sends the data to the signal line 0111 based on values set in advance in the DMA unit. Output data to connected hardware.

(Fixing temperature control by image analysis)
FIG. 3 is a block diagram showing a configuration of fixing temperature control by image analysis in the present embodiment. A controller control 0301 indicates a control configuration in the controller 0101 and has an image analysis process 0302. The image analysis process 0302 calculates a toner application amount described later with reference to FIG. 6 for the image data generated by the image processing unit 0105, and notifies the printer control 0303 of it. A printer control 0303 indicates a control configuration in the printer 0122 and has a fixing temperature adjustment control 0304. The fixing temperature adjustment control 0304 adjusts the temperature of the fixing device unit 0127 when fixing the toner image on the sheet based on the notified toner amount.

(Printer configuration)
FIG. 4 is a cross-sectional view of the printer 0122. The printer 0122 transfers the toner image formed on the photosensitive drum 11 to the sheet P, fixes the image on the sheet P by the fixing device 40, and forms the image on the sheet P.

  The printer 0122 includes an image forming unit 10 that forms toner images of respective colors of Y (yellow), M (magenta), C (cyan), and Bk (black). The image forming unit 10 includes four photosensitive drums 11 (11Y, 11M, 11C, and 11Bk) corresponding to the colors Y, M, C, and Bk in order from the left side of FIG. Around each photosensitive drum 11, a charger 12, a laser scanner unit 13, a developing device 14, a primary transfer blade 17, and a cleaner 15 are arranged.

  The photosensitive drum 11 is rotationally driven in the arrow direction (counterclockwise direction in FIG. 4) by a driving source. Around the photosensitive drum 11, a charger 12, a laser scanner unit 13, a developing device 14, a primary transfer blade 17, and a cleaner 15 are arranged in order along the rotation direction.

  The surface of the photosensitive drum 11 is charged in advance by a charger 12. Thereafter, the photosensitive drum 11 is exposed by a laser scanner unit 13 that emits laser light in accordance with image information to form an electrostatic latent image. The electrostatic latent image is converted into a Bk color toner image by the developing device 14. At this time, the same process is performed for the other colors. The toner images on the respective photosensitive drums 11 are sequentially primary transferred onto the intermediate transfer belt 31 by the primary transfer blade 17. After the primary transfer, the toner remaining without being transferred to the photosensitive drum 11 is removed by the cleaner 15. In this way, the surface of the photosensitive drum 11 is cleaned, and the next image can be formed.

  The sheets P placed on the feeding cassette 20 or the multi-feed tray 25 are fed one by one by the feeding mechanism and fed to the registration roller pair 23. The registration roller pair 23 temporarily stops the sheet P, and corrects the direction of the sheet P when the sheet P is skewed with respect to the conveyance direction. The registration roller pair 23 sends the sheet P between the intermediate transfer belt 31 and the secondary transfer roller 35 in synchronization with the toner image on the intermediate transfer belt 31. The roller 35 transfers the color toner image on the belt 31 to the sheet P.

  Thereafter, the sheet P is fed toward the fixing device 40. The fixing device 40 heats and pressurizes the toner image on the sheet P to fix it on the sheet P. The sheet P that has exited the fixing device 40 passes through a conveyance path and is sent out onto a paper discharge tray by a paper discharge roller. When duplex printing is specified, the sheet printed on the first side is sent out onto the paper discharge tray by the paper discharge roller, and immediately before the trailing edge passes through the paper discharge roller, Rotation is converted to reverse. As a result, the sheet P is switched back and introduced into the re-conveying path. Then, the front and back surfaces are reversed and conveyed to the registration roller pair 23 again. Thereafter, as in the case of the first side, it is transferred and fixed, and is discharged as a double-sided printed matter.

(Fixing temperature control)
Next, a method for calculating the fixing temperature necessary for fixing the target page according to the detected toner amount as a result of the toner amount detection will be described.

  As described above, the toner application amount means the toner application amount per unit area on the image data. In order to fix the toner on the recording paper without causing a fixing failure, it is necessary to set the temperature of the fixing device 40 to a fixing temperature at which the maximum amount of applied toner in the target page can be reliably fixed. At this time, since the maximum amount of applied toner differs depending on the image data to be printed, the temperature required for fixing also differs for each image data. The larger the maximum amount of applied toner, the higher the temperature required for the fixing device 40 to fix the toner.

  FIG. 5B is a diagram showing the relationship between the toner amount in the image forming apparatus 0101 according to the present embodiment and the fixing temperature required for the toner fixing by the fixing device 40. In FIG. 5A, the horizontal axis indicates the amount of applied toner, and the vertical axis indicates the temperature required for the fixing device 40 to fix the toner onto the recording paper.

  In FIG. 5A, for example, when the result of toner application amount detection is 200%, the minimum temperature required for toner fixing is T1. Similarly, when the applied toner amount detection results are 150%, 100%, and 50%, the minimum temperatures required for toner fixing are T2, T3, and T4, respectively. If the fixing temperature of the fixing device 40 is increased to a temperature at which the maximum toner load value appearing in the image data can be fixed, a problem of toner fixing failure may occur when the toner related to the image data is subjected to toner fixing processing. There is no. Therefore, the minimum temperature necessary for fixing the toner to be printed can be obtained from the result of the toner amount detection.

FIG. 5B is a diagram showing a data table in which the relationship between the applied toner amount and the fixing temperature of the fixing device 40 is normalized. In FIG. 5B, for example, when the result of toner application amount detection is 200% or more, the lowest temperature required for the fixing device 40 to fix the toner onto the recording paper is the highest reference temperature (ref). On the other hand, when the result of detecting the amount of applied toner is 50% or less, the minimum temperature required for the fixing device 40 to fix the toner onto the recording paper 11 is 10 degrees lower than the reference temperature (ref) (ref-10 °) Can be seen.

(Toner load detection processing)
FIG. 6A is a flowchart illustrating the applied toner amount detection process. Note that the CPU 0103 performs the applied toner amount detection processing shown in the flowchart. In step S06101, a one-line search window is set at the upper end of the image for the input bitmap format image data. In step S06102, the amount of applied toner for each line is calculated for the line for which the search window is set. FIG. 7 is a diagram for explaining the applied toner amount detection processing. In FIG. 7, 7011 is the amount of applied toner in line units.

  In step S06103, the amount of applied toner in units of lines obtained in step S06102 is compared with the continuous line result stored in the RAM 0104, and the smaller one is overwritten in the RAM 1004 as a new continuous line result. If no value is held in the continuous line result, the amount of applied toner in units of lines obtained in S06102 is stored in the RAM 0104 as a new continuous line result. As indicated by reference numeral 7012 in FIG. 7, the minimum value of the amount of applied toner on eight consecutive lines is set as a continuous line result 7013.

  If it is determined in S06104 that the position of the search window is on a line that is a multiple of 8 from the top, the process proceeds to S06106. When the position of the search window is on a line other than a multiple of 8 counted from the upper end, the process proceeds to S06105.

  In S06105, the search window is moved down one line, and the process returns to S06102. In S06106, the larger of the continuous line result stored in the RAM 0104 and the final result stored in the RAM 0104 is overwritten in the RAM 0104 as a new final result. If no value is held in the final result, the continuous line result is stored in the RAM 0104 as a new final result. As indicated by reference numeral 7014 in FIG. 7, the maximum value among the continuous line results is set as the final result of the applied toner amount.

  If the position of the search window is at the lower end of the image in S06107, the process proceeds to S06108. If the position of the search window is not at the lower end of the image, the process proceeds to S06105. In step S06108, the final result stored in the RAM 0104 is stored in the RAM 0104 as the toner applied amount of this image.

  FIG. 6B is a flowchart showing the applied toner amount detection processing for each line. Note that the CPU 0103 performs the applied toner amount detection processing for each line shown in the flowchart.

  First, in step S06201, a 16 × 1 pixel search window is set at the left end of the image for the input bitmap format image data. There is a search window as 7002 in FIG. In step S06202, the applied toner amount is calculated for the pixel group in which the search window is set. The sum of the density of each color is obtained for each pixel, and the sum of the highest density among the pixels in the search window is set as the toner application amount.

  In S06203, the larger amount of the applied toner amount obtained in S06202 and the line result stored in the RAM 0104 is overwritten in the RAM 0104 as a new line result. If no value is held in the line result, the applied toner amount obtained in S06202 is stored in the RAM 0104 as a new line result. As indicated by reference numeral 7003 in FIG. 7, the maximum value among the line results is set as the toner applied amount of this line.

  If the position of the search window is at the right end of the image in S06204, the process proceeds to S06206. If the position of the search window is not at the right end of the image, the process proceeds to S06205. In S06205, the search window is moved 4 pixels to the right, and the process returns to S06202. In step S06206, the line result stored in the RAM 0104 is stored in the RAM 0104 as the toner applied amount of this line.

(Calculation of estimated toner usage)
FIG. 8 is a diagram showing toner estimated usage amount calculation processing in the present embodiment. Note that the estimated toner usage calculation unit 0202 performs the estimated toner usage calculation processing shown in the flowchart. First, for the input bitmap format image data, a one-pixel cursor is set at the upper left end 8001 of the image. The color density of the pixel where the cursor is set is acquired, and the cursor is set to the pixel 8002 one right.

  Similarly, the acquisition of the color density of the pixel and the movement of the cursor are repeated. When the cursor is set at the right end 8003 of the image, the color density of the pixel is acquired, and the cursor is set at the left end pixel 8004 one line below. Similar processing is repeated, and when the cursor is set at the lower right end 8005 of the image, the color density of the pixel is acquired, and the sum of the color densities of all the pixels is set in the RAM 0104 as the estimated toner usage.

  FIG. 9 is a flowchart showing the estimated toner usage calculation processing in this embodiment. Note that the estimated toner usage calculation unit 0202 performs the estimated toner usage calculation processing shown in the flowchart.

  First, in S08001, for the input bitmap format image data, a one-pixel cursor is set at the upper left corner of the image. In S08002, for the pixel on which the cursor is set, the color density of the pixel on which the cursor is set is acquired. In S08003, the sum of the color density obtained in S08002 and the color density stored in the RAM 0104 is added and overwritten in the RAM 0104. If it is determined in S08004 that the cursor is not at the right edge of the image, the process proceeds to S08005.

  In S08005, the cursor is moved to the right by one pixel, and the process returns to S08002. If it is determined in S08006 that the cursor is not at the lower end of the image, the process proceeds to S08007. In S08007, the cursor is moved to the left end of the image one line below, and the process returns to S08002. In step S08008, the total color density stored in the RAM 0104 is recorded in the RAM 0104 as the estimated toner usage.

(Image analysis processing of the first embodiment)
FIG. 10 is a diagram for explaining image analysis execution control processing in the present embodiment. The RIP unit 0214 generates image data for each page based on the print data received from the external device 0124. The estimated toner usage calculation unit 0202 calculates the estimated toner usage based on the image data generated by the RIP unit 0214. The image analysis process 0302 performs image analysis on the image data and calculates the applied toner amount. The printer I / F 0113 controls the page order based on the information specified by the print data, and sends the image data to the printer 0122 and notifies the applied toner amount.

  FIG. 8 shows the processing order of a case where two pages of image data are printed on one side with one copy. On the first page, the estimated toner usage is smaller than the minimum amount of applied toner in the detection area and is image data that does not require image analysis. On the second page, the estimated toner usage is greater than a predetermined value, and an image that requires image analysis. It is data. The image data for the first page is not subjected to the image analysis process 0302 because the estimated toner usage calculated by the toner estimated usage calculation unit 0202 is smaller than a predetermined value. On the other hand, the image data for the second page is subjected to the image analysis process 0302 because the estimated toner usage calculated by the toner estimated usage calculation unit 0202 is larger than a predetermined value.

  FIG. 11A is a flowchart showing print processing in the present embodiment. First, in step S <b> 11101, the CPU 0103 inputs image data using the network I / F 0114. Print information of the image is acquired from the captured input image data and the header of the image data. The acquired input image data and print information are stored on the external storage device 0123. In step S <b> 11102, the CPU 0103 uses the image processing unit 0105 to generate output image data to be transferred to the printer 0122 from the input image data and print information held on the external storage device 0123.

  The generated output image data is stored on the external storage device 0123. In step S <b> 11103, the CPU 0103 issues a print instruction to the printer 0122 via the printer I / F 0113. The output image data held on the external storage device 0123 is temporarily stored on the RAM 0104, and then transferred to the printer 0122 via the printer I / F 0113. The printer 0122 receives image data from the CPU 1003 via the printer I / F 0113, performs image formation and paper conveyance control, and executes print processing.

  FIG. 9B is a flowchart showing image processing in the present embodiment. Image processing is executed by the image processing unit 0105 in accordance with instructions from the CPU 0103. First, in S11201, input image data stored in the external storage device 0123 is acquired. The acquired print information is held on the RAM 0104. In step S11202, the input image data is converted into bitmap format image data using the image processing unit 0105 based on the information in the image data information portion stored in the RAM 0104.

  For example, if the image format of the image data information is JPEG, input image data is input from the RAM 0104 to the JPEG unit 0212 via the DMA unit 0201. The JPEG unit 0212 performs JPEG decompression on the JPEG-compressed image data input from the DMA unit 0201 to convert the image data into bitmap format image data, and outputs the image data to the DMA unit 0203. The DMA unit 0203 stores the image data output from the JPEG unit 0212 in the RAM 0104.

  In step S11203, the estimated toner usage calculation unit 0202 calculates the estimated toner usage for the bitmap format image data stored on the RAM 0104, and stores the estimated toner usage in the RAM 0104. In step S11204, JBIG compression is performed on the bitmap format image data stored on the RAM 0104. In JBIG compression processing, image data in bitmap format is input from the RAM 0104 to the JBIG unit 0211 via the DMA unit 0201 of the image processing unit 0105.

  The JBIG unit 0211 performs JBIG compression on the bitmap format image data input from the DMA unit 0201 and outputs the image data to the DMA unit 0203. The DMA unit 0203 stores the compressed image data output from the JBIG unit 0211 in the RAM 0104. In step S11205, the compressed image data on the RAM 0104 is stored in the external storage device 0123.

  In step S11206, the print information read in step S11201 is analyzed to detect a print setting including the number of copies and both sides. If it is determined in step S11207 that the estimated toner usage is less than the predetermined value and fixing temperature adjustment image analysis processing is not required, the process advances to step S11208. Otherwise, the process proceeds to S11209. In step S11208, a predetermined fixed toner amount is notified to the printer 0122 via the printer I / F 0113.

  In step S11209, the compressed data stored in step S11204 is decompressed and stored in the RAM 0104. In step S <b> 11210, toner applied amount detection processing is performed on the bitmap format image data stored on the RAM 0104. In step S11211, the amount of applied toner calculated in step S11210 is notified to the printer 0122 via the printer I / F 0113.

  FIG. 11C is a flowchart showing image transfer processing in the present embodiment. Note that the image transfer processing shown in the flowchart is executed by the CPU 0103. In step S11301, a print instruction command is transmitted to the printer 0122 via the printer I / F 0113. In step S11302, when an image transfer request is received from the printer 0122 via the printer I / F 0113, the compressed output image data held in the external storage device 0123 is temporarily stored in the RAM 0104. In steps S11303 and S11304, the compressed output image data is transferred to the printer 0122 via the printer I / F 0113 while being decompressed.

(Effects of the first embodiment)
FIG. 12 is a diagram showing the effect of image analysis execution determination in the present embodiment. FIG. 12A illustrates a conventional toner application amount notification and printing timing.

  For page N, the controller 0101 performs image generation and toner application amount detection for one page, and then the controller 0101 issues a toner application amount notification and print instruction for the first page to the printer 0122. Next, in accordance with a print instruction for one page from the printer 0122, an image data transmission start instruction is issued to the controller 0101. Then, the controller 0101 performs image transfer in synchronization with the image data transmission start instruction for one page from the printer 0122.

  On the other hand, for the two pages, the image generation for two pages and the toner application amount detection are performed after the completion of each processing so that the image generation for one page and the toner application amount detection do not compete. After the controller 0101 generates the image for the two pages and detects the applied toner amount, the controller 0101 issues a notification for the applied toner amount for the two pages and a print instruction to the printer 0122.

  Next, in accordance with a print instruction for one page from the printer 0122, an instruction to start transmission of image data for two pages is issued to the controller 010 so that transmission of image data for the first and second pages does not become less than a predetermined time. Then, in synchronization with a 2-page image data transmission start instruction from the printer 0122, the controller 0101 performs 2-page image transfer.

  FIG. 12B is a diagram illustrating the conventional toner application amount notification and printing timing in this embodiment. On pages 1 and 2, the controller 0101 does not detect the applied toner amount, and notifies the printer 0122 of the applied toner amount with a fixed value. Therefore, it is possible to notify the print instruction of the controller 0101 at an earlier timing than in the conventional case.

  As a result, it can be seen that the first print is faster in FIG. 12B than in FIG.

  According to this embodiment, since image data analysis is omitted for an image with a small estimated toner usage, it is possible to prevent print performance from being degraded by unnecessary image data analysis processing.

(Image analysis processing of the second embodiment)
FIG. 13 is a diagram for explaining image analysis execution control processing in the second embodiment. The RIP unit 0214 generates image data in block units from the print data received from the external device 0124. Based on the block unit image data generated by the RIP unit 0214, the toner estimated usage calculation unit 0202 calculates the estimated toner usage for each block. The image analysis process 0302 performs image analysis only for the block image in which the estimated toner usage exceeds a predetermined value, and calculates the applied toner amount. For a block image whose estimated toner usage is less than a predetermined value, a fixed value is set for the estimated toner usage without performing image analysis. The printer I / F 0113 performs transfer of image data and notification of the amount of applied toner to the printer 0122 based on information specified by the print data.

  In FIG. 13, the input image is divided into four blocks, and only the second block 08102 has the estimated toner usage amount exceeding a predetermined value, so that the image analysis process 0302 is performed. For the other blocks, the estimated toner usage amount is predetermined. Image analysis is not performed because the value is less than.

FIG. 9B is a flowchart showing image analysis execution control processing in the second embodiment. Image processing is executed by the image processing unit 0105 in accordance with instructions from the CPU 0103.
First, in step S14101, input image data stored in the external storage device 0123 is acquired. The acquired print information is held on the RAM 0104.

  In step S14102, the input image data is converted into bitmap format image data in units of blocks using the image processing unit 0105 based on the information in the image data information portion held on the RAM 0104. For example, if the image format of the image data information is JPEG, input image data is input from the RAM 0104 to the JPEG unit 0212 via the DMA unit 0201. The JPEG unit 0212 performs JPEG decompression on the JPEG-compressed image data input from the DMA unit 0201 to convert the image data into bitmap format image data, and outputs the image data to the DMA unit 0203. The DMA unit 0203 stores the image data output from the JPEG unit 0212 in the RAM 0104.

  In step S <b> 14103, the estimated toner usage calculation unit 0202 calculates the estimated toner usage for the bitmap-format image data stored in the RAM 0104, and stores the estimated toner usage in the RAM 0104.

  In step S14104, JBIG compression is performed on the bitmap format image data stored on the RAM 0104. In JBIG compression processing, image data in bitmap format is input from the RAM 0104 to the JBIG unit 0211 via the DMA unit 0201 of the image processing unit 0105. The JBIG unit 0211 performs JBIG compression on the bitmap format image data input from the DMA unit 0201 and outputs the image data to the DMA unit 0203. The DMA unit 0203 stores the compressed image data output from the JBIG unit 0211 in the RAM 0104. In step S14105, the compressed image data on the RAM 0104 is stored in the external storage device 0123.

  If it is determined in S14106 that all blocks have been processed, the process advances to S14107. If processing of all blocks has not been completed, the process returns to S14102. In step S14107, the print information read in step S14101 is analyzed to detect a print setting including the number of copies and both sides.

  If it is determined in step S14108 that the estimated toner usage amount of the block is less than the minimum toner application amount in the detection area and the image analysis processing for fixing temperature adjustment is unnecessary, the process advances to step S14111. Otherwise, the process proceeds to S14209. In step S14108, a predetermined fixed toner amount is notified to the printer 0122 via the printer I / F 0113. In step S14109, the compressed data stored in step S14104 is decompressed and stored in the RAM 0104.

  In step S <b> 11210, toner applied amount detection processing is performed on the bitmap format image data stored on the RAM 0104. In step S11211, the amount of applied toner calculated in step S11210 is notified to the printer 0122 via the printer I / F 0113.

(Effect of 2nd Embodiment)
FIG. 15 is a diagram illustrating the effect of the image analysis execution determination in the present embodiment. FIG. 15A illustrates a conventional toner application amount notification and printing timing.

  For one page, the controller 0101 performs image generation and toner application amount detection for one page, and then the controller 0101 issues a toner application amount notification and print instruction for the first page to the printer 0122. Next, in accordance with a print instruction for one page from the printer 0122, an image data transmission start instruction is issued to the controller 0101. Then, the controller 0101 performs image transfer in synchronization with the image data transmission start instruction for one page from the printer 0122.

  On the other hand, for the two pages, the image generation for two pages and the toner application amount detection are performed after the completion of each processing so that the image generation for one page and the toner application amount detection do not compete. After the controller 0101 generates the image for the two pages and detects the applied toner amount, the controller 0101 issues a notification for the applied toner amount for the two pages and a print instruction to the printer 0122.

  Next, in accordance with a print instruction for one page from the printer 0122, an instruction to start transmission of image data for two pages is issued to the controller 010 so that transmission of image data for the first and second pages does not become less than a predetermined time. Then, in synchronization with a 2-page image data transmission start instruction from the printer 0122, the controller 0101 performs 2-page image transfer.

  FIG. 15B is a diagram illustrating the conventional toner application amount notification and printing timing. In one page, detection of the applied toner amount of an image block having an estimated toner usage amount of 0 is skipped. In addition, since the estimated toner usage amount of all blocks in page 2 is 0, the controller 0101 does not detect the applied toner amount and notifies the printer 0122 of the applied toner amount with a fixed value. Therefore, it is possible to notify the print instruction of the controller 0101 at an earlier timing than in the conventional case.

As a result, it can be seen that printing is faster in FIG. 15B than in FIG.
According to the present embodiment, since image data analysis is omitted for blocks with a small estimated toner usage, it is possible to prevent print performance from being degraded by unnecessary image data analysis processing.

0100 Image forming apparatus 0101 Controller 0121 Operation unit 0122 Printer 0123 External storage device 0124 External device 0102 ROM
0103 CPU
0104 CPU
0103 Central processing unit (processor)

Claims (1)

A receiving unit for receiving print data;
A conversion unit that converts the print data received by the reception unit into image data;
An image forming unit that forms an image on recording paper based on the image data converted by the conversion unit;
A fixing unit for fixing the image formed on the recording paper by the image forming unit;
A controller that analyzes the image data converted by the converter and determines a fixing temperature of the fixing unit based on a result of the analysis.
The control unit compares the estimated toner usage amount of the print data with the minimum density integrated value of the predetermined size of the filled area, and determines the fixing temperature without analyzing the image data when the estimated toner usage amount is smaller. An image forming apparatus.