JP2015084054A - Image processor, control method thereof, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processor capable of decreasing the fixation temperature to a low value within a range where a fixation defect does not occur when the fixation temperature is determined according to the toner attachment amount, in contrast with many cases where the fixation temperature is set higher than a temperature in a range where a fixation defect does not occur.SOLUTION: An image processor which determines a fixation temperature for an input image during printing includes: calculation means for calculating a toner attachment amount according to the pixel of the input image; storage means for storing in a storage section the minimum value of the toner attachment amount of pixels contained in a local area having a size of M×N pixels as a representative value in the local area, while shifting in the input image the local area by a prescribed amount of pixels; and determination means for setting the maximum value among the representative values stored in the storage section as a toner attachment amount for the input image, and determining a fixation temperature for the input image on the basis of the toner attachment amount.

Description

  The present invention relates to an image processing apparatus, a control method therefor, and a program, and more particularly to a technique for performing temperature control in a heating apparatus.

  In general, an electrophotographic image processing apparatus forms an image by developing an electrostatic latent image formed on a photoreceptor with toner, transferring the toner image onto a sheet, and fixing the image on the sheet with heat and pressure. . In such an electrophotographic printing apparatus, sufficient heat is required to reliably fix the toner image. Therefore, the heat fixing mechanism for fixing the toner onto the paper consumes the most energy.

  On the other hand, from the viewpoint of saving power consumption, we want to reduce the amount of heat applied to fixing to the minimum amount of heat necessary. Therefore, various methods for enabling efficient and wasteful heat supply in the heat fixing mechanism have been proposed. For example, a method has been proposed in which an image is divided into regions, a pixel density for each divided region is obtained, and a fixing temperature is determined based on the pixel density (see Patent Document 1).

JP 2009-223239 A

  In the prior art documents, since the fixing temperature is calculated based on the pixel density for each divided region, the temperature is often set higher than the fixing temperature in a range where no fixing failure occurs. That is, in the prior art documents, the fixing temperature cannot be lowered to a lower value within a range where no fixing failure occurs.

  In order to solve the above problems, the present invention has the following configuration. That is, an image processing apparatus for determining a fixing temperature at the time of printing for an input image, the calculation unit calculating a toner application amount for each pixel of the input image, and the input image having a size of M × N pixels. Storage means for storing the minimum value of the toner applied amount of the pixels included in the local area as a representative value in the local area while shifting the local area by a predetermined shift amount; And determining means for determining a fixing temperature for the input image based on the toner applied amount based on a toner applied amount in the input image.

  The fixing temperature can be lowered to a lower value as long as fixing failure does not occur.

FIG. 2 is a block diagram showing a conceptual configuration of a control system in the image processing apparatus according to the present embodiment. The flowchart which shows the procedure of the whole operation | movement which concerns on this embodiment. 6 is a flowchart showing fixing temperature calculation processing according to the first embodiment. FIG. 6 is a diagram illustrating an example in which a toner applied amount and a representative value of input image data according to the present embodiment are digitized. 9 is a flowchart showing fixing temperature calculation processing according to the second embodiment. 9 is a flowchart showing fixing temperature calculation processing according to the third embodiment. 10 is a flowchart showing fixing temperature calculation processing according to a fourth embodiment. 10 is a flowchart illustrating a fixing temperature calculation process according to a fifth embodiment. FIG. 3 is a conceptual diagram illustrating a relationship between a temperature control unit and a fixing unit according to the present embodiment. The figure which shows notionally the LUT which concerns on this embodiment.

  Hereinafter, the form for implementing this embodiment is demonstrated using drawing.

[Device configuration]
FIG. 1 is a block diagram showing a conceptual configuration of a control system in the image processing apparatus 110 according to the present embodiment. Examples of the image processing apparatus 110 include a printing apparatus, a copier, and an MFP (Multi Function Peripheral). In FIG. 1, the control unit 100 is a control unit that controls the entire image processing apparatus 110. The control unit 100 includes a calculation unit 101 that executes various calculation and control processing operations, a storage unit 102 that stores a toner applied amount conversion LUT (Look Up Table) and a fixing temperature conversion LUT according to the present embodiment, and a signal value. An image processing unit 103 that performs analysis processing is included.

  The image input unit 104 receives input image data from a PC (Personal Computer) connected via an external medium or a network. The control unit 100 reads out from the image input unit 104 image data on which the fixing temperature calculation process according to the present embodiment is performed. The control unit 100 transmits the result of the fixing temperature calculation process to the output control unit 105. The output control unit 105 performs device control in the electrophotographic image processing apparatus 110. The heating control unit 106 performs heating control for fixing the toner onto the paper, and the calculated fixing temperature information is reflected on the heating control unit 106.

  The image output unit 107 outputs the image data subjected to image processing by the control unit 100 to a medium such as paper. The fixing unit 108 includes a fixing roller 109, controls the temperature of the fixing roller 109 based on the temperature information set in the heating control unit 106, and fixes an unfixed toner image on a medium such as paper. The image data after image processing that has been subjected to image processing by the control unit 100 is transferred to the image output unit 107. FIG. 9 is a conceptual diagram showing the relationship between the heating control unit 106 and the fixing unit 108 according to the present embodiment. The heating control unit 106 transmits the set temperature information to the image output unit 107 together with the image data.

  In the present embodiment, the image processing apparatus may acquire any image data using any method. For example, image data created by a user on a predetermined application may be acquired from the image input unit 104. When the image processing apparatus 110 includes a removable media reading device (not shown) such as an optical disk or a USB storage device, image data may be input via the media. Furthermore, when the image processing apparatus 110 is connected to an external apparatus (not shown) via a network, the image data may be acquired via the network.

  In the present embodiment, the control unit 100 may be provided on the MFP or printer side, or may be provided in a PC connected to the MFP or printer via a network or a USB cable.

<First embodiment>
FIG. 4 conceptually shows processing for deriving an appropriate fixing temperature from input image data. FIG. 4A partially enlarges the input image data, and shows the amount of applied toner for each pixel. Here, the size of the local area (M × N pixels) is described as a size of 3 × 3 pixels. Also, the horizontal direction in FIG. 4A is the main scanning direction, and the vertical direction is the sub-scanning direction.

  In order from the top of the input image data, the minimum value from the applied toner amount for each pixel in the local area is stored in the storage unit 102 as a representative applied toner amount value in the local area. Scanning is performed while shifting one pixel at a time in the main scanning direction and the sub-scanning direction, and a toner applied amount representative value is obtained until the local area reaches the image end of the input image data. FIG. 4B shows an example in which the applied toner representative values obtained for the input image data in FIG.

  As shown in FIG. 4A, the local region is shifted pixel by pixel in the main scanning / sub-scanning direction from the image end (in this case, the upper right end of the image), and the right end and the lower end of the local region are respectively in the main scanning / sub-scanning direction. The toner applied amount representative value is stored until the image end in the scanning direction is reached. Accordingly, when the size of the input image data is P × Q (pixels) and the local region size is M × N (pixels), the number of applied toner representative values is (P−M + 1) × (Q−N + 1). It becomes. Since the size of the input image data shown in FIG. 4 is 15 × 11, the number of applied toner representative values is 117 (= 13 × 9).

  The maximum applied toner amount is set as the applied toner amount of the page of interest from the representative applied toner amount. That is, in FIG. 4B, since the maximum value of the toner application amount representative value is 150%, 150% is the toner application amount on this page. The fixing temperature conversion LUT that converts the applied toner amount into the fixing temperature is used to set the fixing temperature of the page, and the result is sent to the output control unit 105.

  In the first embodiment, the input image data is an 8-bit multilevel image (contone image) composed of four colors of CMYK. Hereinafter, a process for calculating the applied toner amount from the signal value of the input image data and deriving an appropriate fixing temperature will be described. The size M × N of the local area is 16 × 16 pixels.

[Processing flow]
FIG. 2 shows a processing flow in which the control unit 100 derives an appropriate fixing temperature from the input image data according to the present embodiment.

  In step S <b> 201, the control unit 100 reads out the multi-value image data from the image input unit 104 and stores it in the storage unit 102. In step S202, the image processing unit 103 performs image processing such as density adjustment and toner application amount correction on multi-valued image data. In step S <b> 203, the image processing unit 103 calculates the fixing temperature according to the present embodiment, and sends the calculation result to the output control unit 105. This process will be described with reference to FIG.

  In step S <b> 204, the image processing unit 103 performs dither processing on the multivalued image data, and transfers the output result to the image output unit 107. In S <b> 205, the output control unit 105 sends the calculation result to the heating control unit 106. The heating control unit 106 controls the fixing temperature of the fixing roller based on the calculation result. The image output unit 107 executes image output processing.

(Fixing temperature calculation process)
FIG. 3 is a detailed flowchart of the fixing temperature calculation process in S203 of FIG.

  In step S <b> 301, the image processing unit 103 reads input image data stored in the storage unit 102. In step S <b> 302, the image processing unit 103 reads signal values at pixels in the local area with respect to input image data. In step S <b> 303, the image processing unit 103 converts the read pixel signal value into the applied toner amount. The pixel signal value here is a multi-value signal composed of four colors of CMYK, and the image processing unit 103 converts the multi-value signal to the toner application amount for each color using the toner application amount conversion LUT stored in the storage unit 102. Convert. The amount of applied toner for each color obtained by the conversion process is added to obtain the amount of applied toner for each pixel. FIG. 10A conceptually shows the applied toner amount conversion LUT. The vertical axis is the toner loading [%], and the horizontal axis is the signal value. The applied toner amount conversion LUT is a conversion table for calculating the applied toner amount with respect to an input signal value of an 8-bit signal. The applied toner amount conversion LUT may be defined for each color.

  In step S <b> 304, the image processing unit 103 stores, in the storage unit 102, the minimum value among the toner application amounts in the local area as the toner application amount representative value in the local area. In step S <b> 305, the image processing unit 103 shifts the position of the local region that refers to the signal value of the input image data by one pixel in the main scanning direction. In step S306, the image processing unit 103 obtains a representative toner applied amount value in the local region at the shifted position in the same manner as in steps S302 to S304.

  In S307 to S309, the image processing unit 103 repeats the processing for obtaining the applied toner amount representative value in the local area, similar to S302 to S304, to the image end of the input image data. Here, first, the position of the local region is sequentially shifted in the main scanning direction, and when reaching the image end (right end), control is performed so as to shift by one pixel in the sub-scanning direction, and each representative value is obtained.

  In step S <b> 310, the image processing unit 103 obtains the maximum applied toner amount from all the applied toner amount representative values, and sets it as the applied toner amount of the page of interest. In step S <b> 311, the image processing unit 103 uses the fixing temperature conversion LUT stored in the storage unit 102 for the applied toner amount of the page of interest to determine a fixing temperature corresponding to the applied amount of toner of the page of interest. FIG. 10B conceptually shows the fixing temperature conversion LUT. The vertical axis is the fixing temperature [° C.], and the horizontal axis is the applied toner amount [%]. The fixing temperature corresponding to the toner application amount is calculated from the toner application amount of each signal. In the present embodiment, the applied toner amount in FIG. 10B is the total value of the signal values of the respective colors.

  Through the processing as described above, an appropriate fixing temperature can be obtained from input image data having multi-value signals of CMYK four colors. As a result, an appropriate fixing temperature can be obtained for each page.

  The size of the local area (M × N pixels) may be changed according to the aircraft characteristics. For example, in an image processing apparatus having a maximum toner application amount of 200%, if there is a cluster of pixels having a size equal to or larger than M × N pixels and the maximum toner application amount, it is necessary to fix the image at the maximum fixing temperature. That is, the size of the local area is determined so that the fixing temperature with respect to the amount of applied toner of the pixels included in the local area is equal to or lower than the maximum fixing temperature that the image processing apparatus can output during printing.

  In step S <b> 304, the image processing unit 103 selects the minimum toner application amount in the local region as the toner application amount representative value. However, the present invention is not limited to this. For example, an average value of the applied toner amount in the local region may be selected as the representative applied toner amount value.

  In the present embodiment, the signal value of the input image data is a CMYK 4-value multi-value signal, but is not limited thereto. For example, the signal value of the input image data may be monochrome K1 color or may be a binary signal.

  The control unit 100 shown in the present embodiment may be implemented in an image processing apparatus such as a controller in the printer body, or may be implemented in software such as an application in a host computer such as a PC.

  The storage unit 102 holds the fixing temperature conversion LUT. The fixing temperature conversion LUT is held by the output control unit 105, and the image processing unit 103 obtains the amount of applied toner on the page and transmits it to the output control unit 105. There may be.

<Second Embodiment>
In the first embodiment, the processing for obtaining the toner applied amount representative value in the size of the local region (M × N pixels) has been described. The present invention can be applied even when a buffer for N pixels cannot be secured in the sub-scanning direction due to a limitation of a hardware configuration or the like.

  In the second embodiment, a fixing temperature calculation process in a local area size M × L (M> L ≧ 1) will be described. Here, a local area having a size of 16 × 4 pixels will be described. That is, in this embodiment, M = 16, L = 4, and N = 16.

[Processing flow]
FIG. 5 is a flowchart of the fixing temperature calculation process according to the second embodiment. In S501 to S506, the image processing unit 103 stores, in the storage unit 102, the minimum value of the toner applied amount of the pixels in each local region as a representative value, as in the first embodiment.

  In step S <b> 507, the image processing unit 103 selects the maximum value in each line from the representative toner applied amount values in the local area for four lines (that is, for L lines). The value selected here is taken as the line result.

  In step S508, the image processing unit 103 determines whether processing for 12 lines (N−L) or more has been completed. The 12 lines here do not include the first 4 lines. That is, when the processing for 12 lines is finished, the line result for 16 lines is output. If the processing for 12 lines has not been completed (NO in S508), the process proceeds to S512, and the image processing unit 103 shifts the local area by one pixel in the sub-scanning direction and returns it to the first pixel in the main scanning direction. Then, the process returns to S502. If the processing for 12 lines has been completed (YES in S508), the process proceeds to S509.

  In step S <b> 509, the image processing unit 103 selects the minimum toner application amount from the line results for 16 lines, and sets it as a representative value for the focused 16 lines. In step S <b> 510, the image processing unit 103 determines whether the minimum toner application amount selected in step S <b> 509 is the same as the maximum toner application amount of the image processing apparatus 110. If the selected minimum toner amount has reached the maximum toner amount of image processing apparatus 110 (YES in S510), the process proceeds to S514, and image processing unit 103 sets the toner amount of the page of interest as the maximum toner amount. Set. If the maximum amount of applied toner has not been reached (NO in S510), the process proceeds to S511.

  In step S511, the image processing unit 103 determines whether the local area has reached the image end. If not reached (NO in S511), the process proceeds to S512, and the image processing unit 103 shifts the local area by one pixel in the sub-scanning direction and returns it to the first pixel in the main scanning direction. Then, the process returns to S502. If reached (YES in S511), the process proceeds to S513.

  In step S513, the image processing unit 103 selects the maximum applied toner amount from the representative values calculated in step S509, and sets it as the applied toner amount of the page of interest. In step S <b> 514, the image processing unit 103 obtains a fixing temperature corresponding to the amount of applied toner on the page of interest using the fixing temperature conversion LUT.

  According to the present embodiment, an appropriate fixing temperature is calculated even when a local area of M × N size cannot be secured due to hardware limitations such as buffer capacity or when a buffer cannot be secured in the sub-scanning direction due to limitations such as software processing. Can do.

<Third embodiment>
In the first and second embodiments, the input image data is CMYK multilevel data. On the other hand, processing for calculating an appropriate fixing temperature may be performed on image data input as a halftone image.

  In the third embodiment, input image data is CMYK image data subjected to halftone processing. The size of the local area is 16 × 1 pixel. This shows a fixing temperature calculation process in an environment where a buffer cannot be secured in the sub-scanning direction.

[Processing flow]
FIG. 6 is a flowchart of a fixing temperature calculation process for a halftone image according to the third embodiment.

  In step S601, the image processing unit 103 reads input image data. In step S <b> 602, the image processing unit 103 adds the CMYK pixel values in units of 16 × 1 pixels, and obtains an average density of the total values of the four colors.

  In step S <b> 603, the image processing unit 103 converts the calculated average density value into a toner applied amount in units of 16 × 1 pixels using the toner applied amount conversion LUT. In step S <b> 604, the image processing unit 103 stores the applied toner amount in the storage unit 102.

  In S605 to S607, the image processing unit 103 calculates a line result as in S505 to S507 of the second embodiment. In steps S <b> 608 to S <b> 609, the image processing unit 103 obtains representative values for 16 lines and stores them in the storage unit 102 as in steps S <b> 508 to S <b> 509 of the second embodiment.

  In subsequent steps, the image processing unit 103 repeats the process of obtaining the pixel value in units of 16 × 1 pixels up to the image end, obtaining the toner application amount, and obtaining the line result and the representative value, as in the second embodiment. Set the fixing temperature for the page of interest.

  As described above, the same effects as those of the first and second embodiments can be obtained for the halftone image.

<Fourth embodiment>
In the second and third embodiments, the line result is calculated while shifting one line at a time in the sub-scanning direction when obtaining the line result. However, there are cases where the arithmetic unit is shared with other processes such as hardware configuration or software processing. In that case, the fixing temperature calculation process may affect the printing speed.

  In this case, the time required for the fixing temperature calculation process is set in advance as a predetermined processing time, and if the fixing temperature calculation process is not completed within the predetermined processing time, the calculation process is interrupted. Then, the maximum fixing temperature that can be output by the image processing apparatus during printing is determined as the fixing temperature for the page of interest. This is because the printing speed performance is not affected, and the risk of fixing failure occurring in a portion where the fixing temperature calculation process has not been completed is avoided.

[Processing flow]
FIG. 7 is a flowchart for aborting the fixing temperature calculation process according to the fourth embodiment.

  In step S701, the image processing unit 103 reads input image data. In step S702, the image processing unit 103 calculates line results and representative values in the same manner as in steps S602 to S609 of the third embodiment.

  In step S <b> 703, the image processing unit 103 determines whether the elapsed time since the start of the fixing temperature calculation process has reached a predetermined time. If the predetermined time has been reached (YES in S703), the image processing unit 103 interrupts the calculation process and proceeds to S706. If not reached (NO in S703), the process proceeds to S704. It is assumed that the predetermined time is defined in advance and held in the storage unit 102 or the like. In addition, the time from the start of processing is measured and managed by a timer (not shown) such as a timer, for example, at the start of this processing flow.

  In step S <b> 704, the image processing unit 103 determines whether the local area has reached the image end. If the image end has been reached (YES in S704), the process advances to S705 and S707, and the image processing unit 103 selects the maximum value from the representative values in the same manner as in S614 to 615 of the third embodiment, and the page of interest Set the fixing temperature at. If the image edge has not been reached (NO in S704), the process returns to S702.

  In step S706, the image processing unit 103 sets the amount of applied toner on the page of interest as the maximum amount of applied toner, and the process advances to step S707. In step S <b> 707, the image processing unit 103 sets the maximum fixing temperature as the fixing temperature for the page of interest.

  As described above, in the fixing temperature calculation process, it is possible to control so that a load is not applied beyond a predetermined elapsed time.

<Fifth embodiment>
A plurality of checkpoints may be provided during the fixing temperature calculation process, and the shift amount of the local area in the sub-scanning direction may be increased by referring to the processing time and the remaining processing amount at the end of the checkpoint.

  Here, as an example, four check points are equally arranged in one page, and the time required for the fixing temperature calculation process is 500 msec. The input image data has a resolution of 600 dpi, and is a vertically long CMYK halftone image composed of 4500 pixels in the main scanning direction and 6500 pixels in the sub-scanning direction. The fixing temperature calculation process is the same processing method as in the third embodiment.

  Equally arranging four check points in one page is equivalent to arranging check points in a portion obtained by dividing input image data into five equal parts in the sub-scanning direction. That is, in the case of image data of 6500 pixels in the sub-scanning line direction, the first check point is located at a position where the fixing temperature calculation process is started and the process for 1300 lines is completed. For example, it is assumed that the processing time exceeds 100 msec at the time point until the first check point, and it is determined that it exceeds 500 msec if the processing is continued as it is. In this case, the image processing unit 103 increases the shift amount for shifting the local region (16 × 1 pixel unit) in S612 in the third embodiment in the sub-scanning direction. The increase amount at this time is determined based on the processing time that has already passed and the remaining processing amount (in this case, the remaining 5200 lines).

  Similarly, when the second, third, and fourth check points are reached, the image processing unit 103 adjusts the shift amount in the sub-scanning direction. At this time, when N = 16 pixels, the increase amount is controlled not to exceed 16 pixels (shift amount <N). This is to avoid missing a cluster of pixels having a maximum toner application amount of M × N size or more. Note that the arrangement position and number of checkpoints may be determined according to the size of the input image data, whether or not it is a contone, and the like.

[Processing flow]
FIG. 8 is a flowchart showing processing according to the fifth embodiment.

  In step S801, the image processing unit 103 reads input image data. In step S802, the image processing unit 103 calculates line results and representative values in the same manner as in steps S602 to S609 of the third embodiment. In step S803, the image processing unit 103 determines whether the local region has reached the image end. If the end of the image has been reached (YES in step S803), the process advances to step S811. If the image edge has not been reached (NO in S803), the process proceeds to S804.

  In step S804, the image processing unit 103 determines whether a check point has been reached. If the check point has not been reached (NO in S804), the image processing unit 103 returns to S802 and continues to calculate the line result and the representative value. If the check point has been reached (YES in S804), the process proceeds to S805.

  In step S805, the image processing unit 103 calculates the elapsed processing time at the current time. In step S806, the image processing unit 103 calculates the processing elapsed time at the current time and the processing time required for the remaining processing amount. The image processing unit 103 estimates the processing time for the remaining processing amount from the processing amount at the time of the checkpoint and the processing elapsed time at the current time.

  In step S <b> 807, the image processing unit 103 determines whether the fixing temperature calculation process can be completed to the image end within a predetermined time at the current processing pace based on the estimation result of the remaining processing time in step S <b> 806. If it is determined that the image end can be processed without changing the processing pace (YES in S807), the process proceeds to S802, and the image processing unit 103 continues to calculate the line result and representative value for each line up to the next check point. To do. If it is determined that the process is not in time (NO in S807), the process proceeds to S808.

  In step S808, the image processing unit 103 changes the amount by which the M × 1 size local region is shifted in the sub-scanning direction based on the determination in step S807. That is, the image processing unit 103 increases the amount shifted by one line to two lines and three lines. The shift increase amount is changed according to the remaining processing time and the remaining processing amount. At this time, it is controlled not to shift beyond 16 lines. In step S809, the image processing unit 103 calculates a line result for each line of the shift amount changed in step S808.

  In step S810, the image processing unit 103 determines whether or not the shift amount in the sub-scanning direction of the local area should be changed for each check point as in steps S804 to S809, and changes the shift amount. In steps S <b> 811 to S <b> 812, the image processing unit 103 sets the maximum applied toner amount among all the representative values as the applied toner amount on the page of interest as in the steps S <b> 614 to S <b> 615 of the third embodiment. Then, the image processing unit 103 converts the applied toner amount set by using the fixing temperature change LUT into the fixing temperature, and sets it as the fixing temperature in the page of interest.

  In each example, the processing time is set to 500 msec and the input image size is set to 4500 × 6500 pixels. This is an example numerical value. Naturally, the processing speed varies depending on the hardware configuration, the processing speed of the PC, and the like.

  As described above, the load of the calculation process can be controlled by controlling the shift amount of the local region in accordance with the progress of the calculation process of the fixing temperature.

<Other embodiments>
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (13)

An image processing apparatus for determining a fixing temperature at the time of printing for an input image,
Calculating means for calculating a toner applied amount for each pixel of the input image;
In the input image, the minimum value of the toner applied amount of the pixels included in the local region is stored in the storage unit as a representative value in the local region while shifting the local region having the size of M × N pixels by a predetermined shift amount. Storage means,
And determining means for determining a fixing temperature for the input image based on the toner applied amount based on the toner applied amount as a maximum applied value of the representative values stored in the storage unit. An image processing apparatus.   2. The image processing apparatus according to claim 1, wherein when the input image is a contone image, the calculation unit calculates a toner applied amount from each of CMYK signal values in pixels of the input image.   2. The image according to claim 1, wherein when the input image is a halftone image, the calculation unit calculates a toner applied amount from an average density of a sum of CMYK signal values in pixels of the input image. Processing equipment.   The said storage means determines the representative value for every line, when the representative value for one line of the said input image is memorize | stored in the said memory | storage part. The image processing apparatus described.   The storage means determines a representative value for the predetermined number of lines and stores the representative value for the predetermined number of lines when the representative value for the predetermined number of lines of the input image is stored in the storage unit. The image processing apparatus according to claim 1, wherein the image processing apparatus is characterized. A management unit that manages a processing time of processing related to determination of the fixing temperature by the calculation unit, the storage unit, and the determination unit;
When the process related to the determination of the fixing temperature for the input image is not completed within a predetermined processing time, the management unit interrupts the process related to the determination of the fixing temperature for the input image, and the determination unit includes the image processing 6. The image processing apparatus according to claim 1, wherein a maximum fixing temperature that can be output by the apparatus is determined as a fixing temperature for the input image. A determination unit that determines the progress of processing by the calculation unit, the storage unit, and the determination unit for each check point;
6. The determination unit according to claim 1, wherein the determination unit changes the shift amount by which the storage unit shifts the local region based on a processing time at the time when the check point has elapsed and a remaining processing amount. An image processing apparatus according to claim 1.   The image processing apparatus according to claim 7, wherein the shift amount changed by the determination unit is a shift amount in the sub-scanning direction of the input image.   The image processing apparatus according to claim 8, wherein the shift amount changed by the determination unit is smaller than N.   The image processing apparatus according to claim 7, wherein the check point is determined according to a size of the input image.   The image processing apparatus according to claim 1, wherein N in the size of the local area is determined according to a capacity for storing a representative value of the storage unit. An image processing apparatus control method for determining a fixing temperature at the time of printing for an input image, comprising:
A calculation step of calculating a toner application amount for each pixel of the input image;
In the input image, the minimum value of the toner applied amount of the pixels included in the local region is stored in the storage unit as a representative value in the local region while shifting the local region having the size of M × N pixels by a predetermined shift amount. Memory process,
And determining a fixing temperature for the input image based on the toner applied amount based on the toner applied amount as a maximum applied value of the representative values stored in the storage unit. Control method. Computer
Calculating means for calculating a toner applied amount for each pixel of the input image;
In the input image, the minimum value of the toner applied amount of the pixels included in the local region is stored in the storage unit as a representative value in the local region while shifting the local region having the size of M × N pixels by a predetermined shift amount. Storage means,
A program for causing a maximum value of the representative values stored in the storage unit to be a toner applied amount in the input image and functioning as a determining unit that determines a fixing temperature for the input image based on the toner applied amount .

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