JP6755698B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus that forms an image on a sheet according to an input image forming job.

In recent years, there has been an increasing market demand for energy saving in image forming apparatus, and improvement in power consumption of a fixing portion for fixing an image formed on a sheet is required.

By the way, in order to prevent the fixing portion from causing a fixing defect when fixing the toner image on the sheet, it is necessary to adjust the fixing temperature to a temperature at which the toner image placed on the target page can be surely fixed. is there. However, since the amount of toner applied differs depending on the image data to be image-formed, the temperature required for fixing differs for each image data. The larger the toner loading amount, the higher the temperature required for the fixing portion to fix the toner, and the higher the fixing temperature, the higher the power consumption. Therefore, in Patent Document 1, as a method of optimizing the energy consumed in the fixing portion, the image data of the page of interest is analyzed, and the fixing temperature is made variable according to the toner loading amount calculated based on the analysis result. A method has been proposed.

Japanese Unexamined Patent Publication No. 2015-209984

In Patent Document 1, image data is analyzed and the fixing temperature is set based on the analysis result. Therefore, the analysis process of the image data becomes rate-determining, and there is a problem that the time (FPOT (First Print Out Time)) from the receipt of the printing start request to the output of the first sheet of paper is reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the time from receiving a printing start request until the first sheet of paper is output.

In order to achieve the above object, the image forming apparatus of the present invention is an image forming apparatus that forms an image on a sheet according to an input image forming job, and generates raster image data from the print data of the image forming job. Based on the generation means to be generated, the setting means for analyzing the raster image data of the attention page generated by the generation means, and setting the fixing temperature of the attention page based on the result of the analysis, and the raster image data of the attention page. An image forming means for forming an image of the page of interest on the image carrier, a transfer means for transferring the image of the page of interest formed on the image carrier to the sheet, and fixing the image of the page of interest on the sheet. It has a fixing means and a fixing temperature controlling means for controlling the fixing temperature for the attention page based on the fixing temperature of the attention page set by the setting means, and the setting means outputs at least one copy of a printed matter. In this case, the fixing temperature of the N pages from the beginning of the print data of the image forming job is set to a predetermined fixing temperature, and the fixing temperature of the pages after the N + 1 page is set to the fixing temperature based on the result of the analysis. , When outputting multiple copies of printed matter and continuously forming images on the same page for a specified number of copies, the fixing temperature of the N pages from the beginning and the pages after the N + 1 page is set. It is characterized in that the fixing temperature is set based on the result of the analysis .
Further, in order to achieve the above object, the image forming apparatus of the present invention is an image forming apparatus that forms an image on a sheet according to an input image forming job, and raster image data is obtained from the print data of the image forming job. The generation means to be generated, the setting means for analyzing the raster image data of the attention page generated by the generation means, and setting the fixing temperature of the attention page based on the result of the analysis, and the raster image data of the attention page. Based on this, an image forming means for forming an image of the page of interest on the image carrier, a transfer means for transferring the image of the page of interest formed on the image carrier to the sheet, and an image of the page of interest fixed on the sheet. The setting means includes a fixing means for making the image and a fixing temperature controlling means for controlling the fixing temperature for the page of interest based on the fixing temperature of the page of interest set by the setting means, and the setting means produces at least one copy of printed matter. When outputting, the fixing temperature of N pages from the beginning of the print data of the image forming job is set to a predetermined fixing temperature, and the fixing temperature of the pages after N + 1 is set to the fixing temperature based on the result of the analysis. However, when a plurality of copies of printed matter are output and the raster image data of the second and subsequent copies of the attention page is not generated, the fixing temperature of the N pages from the beginning and the pages after the N + 1 pages is fixed. Is set to the fixing temperature based on the result of the analysis.

According to the present invention, it is possible to suppress a decrease in printing speed while controlling the fixing temperature according to the amount of toner loaded.

It is a figure which shows the structure of the image forming apparatus. It is sectional drawing of a printer. It is a conceptual diagram which showed the data flow of a controller and a printer control part. It is a figure which showed the relationship between the toner loading value and the fixing temperature. It is a figure which showed the relationship between the toner loading value and the fixing temperature. It is a figure for demonstrating an example in which image analysis is skipped about N pages from the beginning of an image formation job. It is a flowchart explaining the operation when the job of forming an image on a sheet is executed according to the input image formation job. It is a flowchart explaining the generation of image data, and the analysis process. It is a flowchart explaining the calculation process of a toner loading value. It is a flowchart explaining the transfer process of a raster image data. It is a figure explaining the calculation process of the toner loading amount value. It is a figure for demonstrating the effect of 1st Embodiment. It is a figure for demonstrating an example in which image analysis is skipped for N pages from the head of an image formation job in which double-sided printing is specified. It is a flowchart explaining the analysis processing of the image data in 2nd Embodiment. It is a figure for demonstrating an example in which image analysis is skipped for N pages from the head of an image formation job in which copy group printing is specified. It is a flowchart explaining the analysis process of the image data in 3rd Embodiment. It is a figure for demonstrating the example of the image formation job which has specified the number-sorted printing. It is a flowchart explaining the analysis process of image data in 4th Embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(overall structure)
FIG. 1 is a diagram showing a configuration of an image forming apparatus according to a first embodiment. The image forming apparatus 100 is an apparatus that forms an image on a sheet according to an image forming job received from an external device 124 or the like via a network. The image forming apparatus 100 includes a controller 101, a printer control unit 115, and a printer 122. The controller 101 includes a CPU 102, a ROM, a RAM 104, a storage unit 105, a communication I / F 114, a RIP unit 214, and a printer I / F 113. The CPU 102 is a central processing unit (processor) that controls the image forming apparatus 100 and performs arithmetic processing, and executes each processing based on a program stored in the ROM 103. The ROM 103 is a read-only memory, and stores a system startup program, a program for controlling the printer engine, character data, character code information, and the like. The RAM 104 is a random access memory and is used as an execution area for programs and data. The RAM 104 can also be used as a data storage area for received image files.

The RIP (Raster Image Processor) unit 214 is a processor that generates raster image data, which is image data in a bitmap format, from each print data included in an image formation job. The print data is, for example, PDL (Page Description Language) data.

The printer 122 has a photoconductor drum as an image carrier, an image forming unit that forms an image of the page of interest on a sheet on the photoconductor drum based on raster image data of the page of interest, and an image formed on the sheet. It has a fixing part to be fixed to the sheet.

The storage unit 105 is a large-capacity storage device such as a hard disk drive or an SD card, and is used for a data spool, storage of programs, information files, image data, etc., a work area, and the like.

The controller 101 further includes various interfaces and a system bus 111. The printer I / F 113 is an interface for communicating with the printer control unit 115. The communication I / F 114 is a network interface for connecting the image forming apparatus 100 to the external apparatus 124, for example, via a local area network (LAN). The system bus 111 is a data passage between the structural elements described above.

(Configuration of Printer 122)
FIG. 2 is a cross-sectional view of the printer 122. The printer 122 transfers the toner image formed on the photosensitive drum 11 which is an image carrier to the sheet P, fixes the image on the sheet P by the fixing portion 40, and forms the image on the sheet P.

The printer 122 includes an image forming unit 10 that forms a toner image of each color of Y (yellow), M (magenta), C (cyan), and Bk (black). The image forming unit 10 includes four photosensitive drums 11 (11Y, 11M, 11C, 11Bk) corresponding to each color of Y, M, C, and Bk in order from the left side of FIG. A charger 12, an exposure unit 13, a developing device 14, a primary transfer blade 17, and a cleaner 15 are arranged around the image carrier (photosensitive drum) 11.

The photosensitive drum 11 is rotationally driven in the direction of the arrow (counterclockwise in FIG. 2) by the drive source. A charger 12, an exposure unit 13, a developing device 14, a primary transfer blade 17, and a cleaner 15 are arranged in this order around the photosensitive drum 11 along the direction of rotation thereof.

The surface of the photosensitive drum 11 is precharged by the charger 12. After that, the photosensitive drum 11 is exposed by the exposure unit 13 that irradiates the laser beam in response to the video signal to form an electrostatic latent image. The electrostatic latent image becomes a Bk color toner image by the developing device 14. At this time, the same process is performed for other colors. The toner image on the photosensitive drum 11 is sequentially primary-transferred to the intermediate transfer belt 31 by the primary transfer blade 17. After the primary transfer, the toner remaining untransferred to the photosensitive drum 11 is removed by the cleaner 15. In this way, the surface of the photosensitive drum 11 becomes clean, and the next image can be formed.

The sheets P placed on the feed cassette 20 or the multi-feed tray 25 are fed one by one by the feed mechanism and fed to the resist roller pair 23. The resist roller pair 23 temporarily stops the sheet P, and if the sheet P is skewed with respect to the transport direction, corrects the direction thereof. The resist roller pair 23 feeds 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 intermediate transfer belt 31 to the sheet P. After that, the sheet P is fed toward the fixing portion 40. The fixing unit 40 fixes the transferred toner image to the sheet P by heating the transferred toner image while transporting the sheet P. The fixing unit 40 has a heating heater, and the temperature of the heating heater is controlled by the fixing control unit 128. The sheet P that has exited the fixing portion 40 is sent out onto the paper ejection tray by the paper ejection roller through the transport path.

When double-sided printing is specified in the image forming job, the sheet P having an image formed on the back surface is sent out onto the paper ejection tray by the paper ejection roller, and immediately before the rear end portion passes through the paper ejection roller. The rotation of the paper ejection roller is converted to reverse. As a result, the sheet P is switched back and introduced into the re-transport path. Then, the surface is inverted and conveyed to the resist roller pair 23 again, and an image is formed on the surface of the sheet P. After that, as in the case of the first side, the paper is transferred, fixed, and discharged as a double-sided printed matter.

(Fixation temperature control by image analysis)
FIG. 3 is a conceptual diagram showing a data flow between the controller 101 and the printer control unit 115. First, when the RIP unit 214 of the controller 101 generates the raster image data of the page of interest, the data is transferred to the exposure control unit 127 of the printer control unit 115. The exposure control unit 127 irradiates the photosensitive drum 11 as an image carrier with a laser beam based on the transferred raster image data, and forms an electrostatic image on the photosensitive drum 11. The electrostatic latent image becomes a toner image by the developing device 14, and is transferred to the sheet by the transfer unit 35.

The CPU 102 of the controller 101 analyzes the raster image data of the attention page in order to calculate the toner loading value before the raster image data of the attention page generated by the RIP unit 214 is transferred to the exposure control unit 127. To do. Then, the CPU 102 notifies the fixing temperature control unit 128 of the toner loading value as an analysis result. Upon receiving the notification of the analysis result from the CPU 102, the fixing control unit 128 sets the fixing temperature of the fixing unit 40 based on the analysis result. Then, the fixing control unit 128 adjusts the temperature of the heating heater of the fixing unit 40 so as to reach the target temperature at the timing when the sheet on which the toner image is formed is conveyed to the fixing unit 40.

FIG. 4 is a diagram showing the relationship between the toner loading value calculated from the raster image data of the page of interest and the fixing temperature required for fixing the toner image on the sheet. The horizontal axis in FIG. 4 indicates the toner loading value, and the vertical axis indicates the fixing temperature required for fixing the toner image. In FIG. 4, for example, when the toner loading value obtained from the raster image data of the page of interest is 200%, the fixing temperature is T1. Similarly, when the calculation results of the toner loading amount values are 150%, 100%, and 50%, the fixing temperatures are T2, T3, and T4, respectively.

If the fixing temperature of the fixing unit 40 is raised to a temperature at which the maximum toner loading value appearing in the raster image data can be fixed, the problem of fixing failure does not occur when fixing the toner related to the image data. Therefore, the minimum temperature required for fixing the toner to be printed can be obtained from the result of calculating the maximum toner loading amount from the raster image data of each page.

FIG. 5 is a data table in which the relationship between the toner loading value and the fixing temperature of the fixing unit 40 is normalized. In FIG. 5, for example, when the result of calculating the toner loading amount is 200% or more, the minimum temperature required for the fixing unit 40 to fix the toner on the recording paper is the highest reference temperature (ref). On the other hand, when the result of calculating the toner loading amount is 50% or less, the minimum temperature required for the fixing unit 40 to fix the toner on the sheet is 10 degrees lower than the reference temperature (ref) (ref-10 °). ..

In the present embodiment, the data table shown in FIG. 5 is stored in a storage unit (not shown) of the fixing control unit 128, and the fixing control unit 128 is stored based on this data table and the toner loading value notified from the CPU 102. Sets the fixing temperature. However, the fixing temperature may be set by another method. Further, the data table of FIG. 5 may be stored in the storage unit 105, and the CPU 102 may set the fixing temperature.

(Analysis processing of raster image data)
FIG. 6A is a diagram for explaining an example in which the analysis of the raster image data from the beginning of the input image forming job to the N page is skipped and only the analysis of the raster image data after the N + 1 page is performed. FIG. 6A is an example in which an image forming job for printing one copy of three pages of print data on one side is transmitted from the external device 124 via a network.

The RIP unit 214 generates raster image data from the print data included in the image forming job received from the external device 124 via the communication I / F 114. After that, the CPU 102 analyzes the raster image data generated by the RIP unit 214 and calculates the toner loading value. Further, the CPU 102 controls the page order based on the print information specified in the image forming job, and notifies the printer control unit 115 of the toner loading value and transfers the raster image data.

By the way, when the raster image data of the first page is analyzed, the start of printing is delayed by the time required for the analysis process. As a result, the time from receiving the printing start request to the output of the first printed matter, that is, the FPOT (First Print Out Time) is reduced. In order to avoid this, in the present embodiment, a predetermined fixing temperature is set as the fixing temperature for N pages (N = 1 in the example of FIG. 6) from the beginning of the input image forming job without performing analysis processing. To do. On the other hand, for the images on the pages after N + 1 page, the fixing temperature is set based on the toner loading amount value obtained as a result of the above analysis process.

In this embodiment, the number of reference pages for skipping the analysis of raster image data for calculating the toner loading value is defined as N. In the example of FIG. 6A, N = 1 page. However, the number of pages to be skipped may be a plurality of pages depending on the processing capacity of the CPU 102 and the RIP unit 214 and the printing speed (PPM) of the printer 122. Further, in the present embodiment, the analysis time of the raster image data is shorter than the printing speed per page from the printing speed.

FIG. 6B is an example in which the image analysis of the first page is skipped and the image analysis of the second and subsequent pages is performed as in the case of FIG. 6A. In FIG. 6B, the time from receiving the print start request is provided on the horizontal axis. The reason why N = 1 is set in the image forming apparatus 1011 of the present embodiment is that it is predicted that the image analysis of the second page is completed before the image forming of the second page is started. is there. When the processing capacity of the CPU 102 or the processing capacity of the RIP unit 214 is slow and the printing speed of the printer 122 is high, the image analysis of the second page is still performed at the timing when the printer 122 can form the image of the second page. Is not completed in some cases. In such a configuration, it is desirable to skip multiple pages.

FIG. 7 is a flowchart showing an operation of forming an image on a sheet according to an input image forming job. The program for executing the process shown in the flowchart of FIG. 7 is stored in the ROM 103, expanded in the RAM 104, and executed by the CPU 102.

In S701, the CPU 102 receives an image forming job from the external device 124 via the communication I / F 114. The print data (PDL data) and print information (designation of single-sided printing / double-sided printing, designation of the number of copies, designation of the printing method, etc.) included in the received image forming job are stored in the storage unit 105. In S702, the CPU 102 reads the PDL data stored in the storage unit 105, and causes the RIP unit 214 to generate raster image data. The generated raster image data is stored in the storage unit 105 again. In S703, the CPU 102 analyzes the generated raster image data and calculates the toner loading value. In S704, the CPU 102 temporarily stores the raster image data stored in the storage unit 105 in the RAM 104, and then transfers the raster image data to the printer control unit 115 at the timing when the image transfer request is received from the printer control unit 115. ..

FIG. 8A is a flowchart showing details of the process (S702) for generating raster image data. In S801, the CPU 102 reads the input PDL data of the page of interest of the image forming job from the storage unit 105. The read PDL data is temporarily stored in the RAM 104. In S802, the CPU 102 causes the RAM 104 to generate raster image data, which is image data in a bitmap format, from the PDL data using the RIP unit 214.

In S803, JBIG compression is performed on the raster image data stored in the RAM 104, and the compressed data in S804 is stored in the storage unit 105.

FIG. 8B is a flowchart showing the details of S703. In S805, the CPU 102 analyzes the print information of the PDL data of the page of interest read in S801, and confirms the setting of the number of copies of the document to be printed and the setting of double-sided printing / single-sided printing. Further, the CPU 102 counts the number of pages for which the image data has been analyzed, and confirms which page the attention page for which the image data should be analyzed corresponds to.

In S806, the CPU 102 determines whether or not the page of interest is within the range of pages 1 to N. If it is determined that the page is within the range of pages 1 to N, the process proceeds to S807, and if it is determined that the page of interest is a page after N + 1, the process proceeds to S809.

In S807, the CPU 102 determines whether or not there is a page that is transferring the raster image data to the printer control unit 115. This determination is made, for example, by whether or not the page end command for the attention page is returned from the printer control unit 115 after transferring the raster image data of the attention page to the printer control unit 115. Alternatively, it may be confirmed whether or not there is a page currently being printed or waiting to be printed.

In S808, the CPU 102 determines whether or not the page during transfer of the raster image data determined in S807 is the skip target. That is, it is determined whether the page being transferred is within the range of 1 to N pages. If it is determined that the range is within the range of 1 to N pages, the process proceeds to S812, and if it is determined that the range is not within the range of 1 to N pages, the process proceeds to S809.

In S809, the CPU 102 decompresses the compressed data stored in S804, and stores the raster image data obtained as a result in the RAM 104. In S810, the CPU 102 performs a toner loading value calculation process (FIG. 9) on the raster image data stored in the RAM 104. In S811, the CPU 102 notifies the printer control unit 115 of the toner loading value calculated in S810 via the printer I / F 113. In S812, the CPU 102 notifies the printer control unit 115 of the toner loading value of a predetermined value via the printer I / F 113. As the predetermined value notified in S812, the maximum toner loading value (200% in the present embodiment) appearing in the raster image data is notified. The fixing control unit 128 sets the fixing temperature based on the analysis result notified in S810 or S811.

(Calculation process of toner loading value)
FIG. 9A is a flowchart showing a process of calculating the toner loading value based on the raster image data of the page of interest. The flowchart of FIG. 9A corresponds to S810.

In S901, the CPU 102 sets a search window 1103 (see FIG. 11) for searching one line for the raster image data of the page of interest generated by the RIP unit 214 at the upper end of the raster image data. In S902, the CPU 102 calculates the toner loading value for the line in which the search window 1103 is set. This toner loading value is used as the line representative value. The calculation method of the line representative value will be described later in FIG. 9B. In S903, the CPU 102 overwrites the RAM 104 with the smaller of the line representative value calculated in S902 and the continuous line result stored in the RAM 104 as a new continuous line result. When the value is not stored in the continuous line result, the toner loading value for each line obtained in S902 is stored in the RAM 104 as a new continuous line result. As shown by 1112 in FIG. 11, the minimum value of the toner loading amount of eight continuous lines is taken as the continuous line result 1113.

In S904, the CPU 102 determines whether or not the position of the search window 1103 is on a line that is a multiple of 8 counting from the upper end of the raster image data of the page of interest. If it is determined that the line is a multiple of 8, the process proceeds to S906, and if the line is not a multiple of 8, the process proceeds to S905.

In S905, the CPU 102 moves the search window down one line and returns to S902. In S906, the continuous line result stored in the RAM 104 and the larger one as compared with the final result stored in the RAM 104 are overwritten on the RAM 104 as a new final result. If no value is stored in the final result, the continuous line result is saved in the RAM 104 as a new final result. As shown by 1114 in FIG. 11, the maximum value among the continuous line results is taken as the final result of the toner loading amount.

In S907, the CPU 102 determines whether or not the position of the search window is at the lower end of the image. If it is determined that it is at the lower end, the process proceeds to S908, and if it is determined that it is not at the lower end, the process proceeds to S905.

In S908, the CPU 102 stores the final result stored in the RAM 104 in the RAM 104 as a toner loading value of the raster image data of the page of interest.

FIG. 9B is a flowchart illustrating the details of S902. In S911, the CPU 102 sets a 16x1 pixel search window 1102 at the left end of the image for the input raster image data, and sets the representative value to 1101.

In S912, the CPU 102 calculates the toner loading value for the pixel group in which the search window 1102 is set. The sum of the density values of each color is obtained for each pixel, and the sum of the largest density values among the pixels in the search window is used as the toner loading value of the pixel group.

In S913, the CPU 102 compares the toner loading value obtained in S902 with the line result stored in the RAM 104, and overwrites the RAM 104 with the larger one as a new line result. When the value is not stored in the line result, the toner loading value obtained in S912 is stored in the RAM 104 as a new line result.

In S914, the CPU 102 determines whether or not the position of the search window 1102 is at the right end of the attention line. If it is determined that it is at the right end, the process proceeds to S906, and if it is determined that it is not at the right end, the process proceeds to S915.

In S915, the CPU 102 moves the search window four pixels to the right and returns to S912. In S916, the CPU 102 stores the line result stored in the RAM 104 in the RAM 104 as the toner loading value of this line.

As described above, the toner loading value of the raster image data of the page of interest is stored in the RAM 104. As described above, in the present embodiment, the raster image data of the page of interest is divided into blocks of 16 × 1 pixel units, and the raster image data of the page of interest is obtained from the toner loading value for each block.

FIG. 10 is a flowchart showing details of the raster image data transfer process (S704). In S1001, the CPU 102 transmits a print instruction command to the printer control unit 115 via the printer I / F 113. In S1002, the CPU 102 receives an image transfer request from the printer control unit 115 that has received the print instruction command via the printer I / F 113. Upon receiving this image transfer request, the CPU 102 reads the compressed data stored in the storage unit 105 in S1003 and decompresses the compressed data. The CPU 102 stores the raster image data obtained as a result of the decompression on the RAM 104, and in S1004, transfers the raster image data to the printer control unit 115 via the printer I / F 113. Taking this transfer as an opportunity, the printer control unit 115 and the printer 122 form an image.

(Effect of the first embodiment)
FIG. 12 is a diagram for explaining the effect in the first embodiment. FIG. 12A is a diagram showing the timing of notification of the conventional toner loading value and transmission of the print instruction command. FIG. 12B is a diagram showing the timing of notification of the toner loading value and transmission of the print instruction command in the present embodiment.

In FIG. 12A, the toner loading value is calculated for all pages of the image forming job. On the other hand, in FIG. 12B, the toner loading value is not calculated for the N pages (first and second pages in this example) from the beginning, and a predetermined value (fixed value) is used as the analysis result. The CPU 102 notifies the printer control unit 115. That is, the CPU 102 transmits a print command to the printer control unit 115 immediately after the raster image data is generated by the RIP unit 214. As a result, it can be seen that the FPOT is shortened as compared with FIG. 12 (a).

According to this embodiment, since the image data analysis for N pages from the beginning of the print data is omitted, the performance deterioration of FPOT can be prevented. Further, from page N + 1 onward, it is possible to determine the fixing temperature of the fixing unit 40 based on the analysis result of the raster image data.

(Image analysis processing of the second embodiment)
Next, the second embodiment will be described. In the first embodiment, the number of pages for which the analysis of the raster image data is skipped is fixed regardless of the print setting of the input image formation job. On the other hand, in the second embodiment, an example will be described in which the number of pages for which analysis is skipped is variable depending on whether the input image formation job is set to single-sided printing or double-sided printing.

FIG. 13 is a diagram for explaining an example in which the analysis of raster image data of N pages from the beginning is skipped when single-sided printing or double-sided printing is specified for the image forming job. FIG. 13 shows the raster image data generation process of the RIP unit 214, the raster image data analysis process of the CPU 102, the page order control process of the CPU 102, and the print order of the printer 122, similarly to FIG. In the example of FIG. 13, the job of printing the print data of three pages is described as an example.

By the way, when executing an image forming job in which double-sided printing is specified, the image forming apparatus 100 first forms an image on the back surface of the sheet P, and then forms an image on the front surface. Therefore, the transfer order of the raster image data transferred by the CPU 102 to the printer 122 is 2 → 1 → 3.

FIG. 13A is an example in which single-sided printing is specified in the input image forming job. In this case, as shown in FIG. 6, the analysis process of the raster image data on the first page is skipped in order to avoid a decrease in FPOT. That is, the number of pages N to be skipped is 1. On the other hand, FIG. 13B is an example in which double-sided printing is specified in the input image forming job. In this case, in order to avoid a decrease in FPOT, the analysis processing of the raster image data on the second page as well as the first page is skipped. That is, the number of pages to be skipped is N = 2. FIG. 13C is an example in the case where double-sided printing is specified in the input image forming job, as in FIG. 13B. In FIG. 13C, the time after receiving the print start request is provided on the horizontal axis. In this case, the reason why N = 2 is set is that it is predicted that the image analysis of the fourth page is completed before the image formation of the fourth page, which is the back surface of the second sheet, is started. Is.

FIG. 14 is a flowchart showing the analysis processing of the raster image data in the second embodiment. The second embodiment is described because the only difference is that the flowchart of FIG. 8B in the first embodiment is replaced with FIG. 14, and the other processes are the same as those of the first embodiment. Is omitted. The program for executing the process shown in the flowchart of FIG. 14 is stored in the ROM 103, expanded in the RAM 104, and executed by the CPU 102.

In S1401, the CPU 102 analyzes the print information of the PDL data of the page of interest, and acquires the designation of the number of copies and the designation of double-sided printing / single-sided printing. Further, the CPU 102 counts the number of pages for which image analysis has been performed, and confirms which page of the image forming job corresponds to the page of interest for which image analysis should be performed. In S1402, the CPU 102 determines whether double-sided printing or single-sided printing is specified for the input image forming job. If it is determined that double-sided printing is specified, the process proceeds to S1403, and if it is determined that single-sided printing is specified, the process proceeds to S1404. In S1403, the CPU 102 sets the number of pages N = 2 to skip the analysis of the raster image data. In S1404, the CPU 102 sets the number of pages N = 1 to skip the analysis of the raster image data. The processing after S1405 is the same as in FIG. 8B.

According to the second embodiment, the number of pages for which analysis is skipped is variable depending on whether single-sided printing or double-sided printing is specified for the input image formation job. That is, the number of pages to be skipped is set to 1 when single-sided printing is specified, and the number of pages to be skipped is set to 2 when double-sided printing is specified. As a result, according to the second embodiment, the number of pages affecting the FPOT is changed according to the designation of single-sided printing / double-sided printing, thereby avoiding a decrease in FPOT in both single-sided printing and double-sided printing. While doing so, energy consumption can be optimized.

(Image analysis processing of the third embodiment)
In the third embodiment, an example in which an image forming job specified to print a plurality of copies is input will be described. For example, a printing method called copy group printing may be specified. The number of copies group printing is a printing method in which image data on the same page is continuously printed for the number of copies specified in a job when a plurality of copies of printed matter are output. For example, in the number-of-copy group printing in which three copies of data on three pages are specified to be printed, printing is performed in the order of 1, 1, 1, 2, 2, 2, 3, 3, 3.

In the case of an image forming job in which copy group printing is specified, the CPU 102 transfers the raster image data once generated to the printer 122 for the number of copies. In this case, if a predetermined fixing temperature is set for the raster image data of N pages from the beginning regardless of the image analysis, it may be fixed by an inappropriate temperature on many pages (N × number of copies). Therefore, in the third embodiment, when the number of copies group printing is specified for the input image formation job, the analysis of the raster image data is not skipped. The third embodiment can be realized by modifying a part of the image data analysis process of the first embodiment.

FIG. 15A is a diagram showing an example in the case where the number-of-copy group printing is not specified for the image formation job. In this case, as in the first embodiment, the raster image data is not analyzed for the N pages (1 page) from the beginning. FIG. 15B is a diagram showing an example in the case where the number-of-copy group printing is specified for the image formation job. In this case, although the FPOT is lowered, priority is given to preventing printing at an inappropriate fixing temperature, and raster image data is also analyzed for the N pages from the beginning.

FIG. 16 is a flowchart showing an analysis process of raster image data in the third embodiment. The third embodiment is different only in that the flowchart of FIG. 8B in the first embodiment is replaced with FIG. 16, and the other processing is the same as that of the first embodiment. Is omitted. The program for executing the process shown in the flowchart of FIG. 16 is stored in the ROM 103, expanded in the RAM 104, and executed by the CPU 102.

In S1601, the CPU 102 analyzes the print information of the PDL data of the page of interest, counts the number of pages for which image analysis has been performed, and determines which page of the image forming job the page of interest to be image-analyzed corresponds to. To confirm. In S1602, the CPU 102 determines whether or not the printing method of the number of copies group is specified based on the analysis result of S1601. If it is determined that the printing method of the number of copies group is specified, the process proceeds to S1603, and if it is determined that the printing method of the number of copies group is not specified, the process proceeds to S1605.

In S1603, the CPU 102 acquires the number of copies specified in the image forming job or the setting of the image forming apparatus 100. If the number of copies is N or more, the process proceeds to S806, and if the number of copies is less than N, the process proceeds to S809. The processing after S806 is the same as the flow of FIG. 8B.

According to the third embodiment, when the printing method of the number of copies group printing is specified in the input image forming job, the raster image data is analyzed and the toner loading value is calculated even for the N pages from the beginning. Do not omit the process.

(Image analysis processing of the fourth embodiment)
In the third embodiment, an example in which the number of copies group printing is specified in the image forming job has been described. In the fourth embodiment, an example in which the number-sorted printing is specified will be described. The number-of-copy sort printing is a printing method in which, when outputting a plurality of copies of a printed matter, the image data of each page included in the image forming job is printed in page order to repeatedly print the number of copies. For example, in the case of a job that prints two copies of data on three pages, printing is performed in the order of 1, 2, 3, 1, 2, 3.

FIG. 17 is a diagram for explaining an example of skipping the analysis of the raster image data from the first page to the Nth page when the number-of-copy sort printing is specified for the image forming job. FIG. 17 shows an example of an image forming job in which two copies of data on three pages are printed on one side by a printing method of sort printing. In the case of copy-sort printing, whether or not the RIP unit 214 generates raster image data for the second and subsequent copies depends on the print data received. Specifically, when the received image forming job includes the print data of the second and subsequent copies, the RIP section 214 also generates the raster image data for the second and subsequent copies. On the other hand, if the received image forming job does not include the print data of the second and subsequent copies, the RIP section 214 does not generate the raster image data. Instead, the raster image data generated when the print command of the first copy is transmitted is stored in the storage unit 105, and the raster image data is repeatedly transferred to the printer control unit 115 for the number of copies to cause the printer 122 to perform image formation.

FIG. 17 shows a case where the RIP unit 214 does not generate raster image data for the second and subsequent units. In order to avoid a decrease in FPOT, it is desirable to skip the analysis of the raster image data on the first page. However, if the analysis is skipped, the fixed value toner loading amount is notified to the second and subsequent pages that exceed the skip reference page number N in the page order of the printer 122. Therefore, as shown in FIG. 17, when the number-of-copy sort printing is specified for the image formation job and the RIP unit 214 does not generate the raster image data for the second and subsequent copies, the toner loading amount value based on the image analysis Is not calculated.

FIG. 18 is a flowchart showing the analysis processing of the raster image data in the fourth embodiment. The fourth embodiment is different only in that the flowchart of FIG. 8B in the first embodiment is replaced with FIG. 16, and the other processing is the same as that of the first embodiment. Is omitted. The program for executing the process shown in the flowchart of FIG. 18 is stored in the ROM 103, expanded in the RAM 104, and executed by the CPU 102.

In S1801, the CPU 102 analyzes the print information of the PDL data of the page of interest, counts the number of pages and the number of copies for which the raster image data has been analyzed, and the number of pages of interest for which the image analysis should be performed is the number of pages of the image formation job. Check if it applies to your eyes. In S1802, the CPU 102 determines whether or not the printing method for sorting the number of copies is specified based on the analysis result of S1801. If it is determined that the printing method for the number of copies sort is specified, the process proceeds to S1803, and if it is determined that the printing method for the number of copies sort is not specified, the process proceeds to S1806.

In S1803, the CPU 102 determines whether or not to generate the raster image data for the second and subsequent copies. Specifically, this determination is made based on whether or not the received image forming job includes the PDL data of the second and subsequent copies. When the PDL data of the second and subsequent copies is included in the image forming job, it is determined that the raster image data is generated, and the process proceeds to S1804. If the PDL data of the second and subsequent copies is not included, it is determined that the raster image data is not generated, and the process proceeds to S809.

Next, in S1804, based on the information on the number of copies counted in S1801, the CPU 102 determines whether or not the page of interest is the first copy. If it is determined to be the first copy, the process proceeds to S806, otherwise the process proceeds to S809. Since the processing after S806 is the same as that in FIG. 8B, the description thereof will be omitted.

According to the fourth embodiment, when the number of copies sort printing is specified in the input image forming job, if it is the first copy, the fixing temperature is set to a predetermined fixing temperature without performing image analysis, and 2 If it is after the part, set the fixing temperature based on the image analysis result. As a result, it is possible to reliably set the fixing temperature of the fixing portion based on the analysis result of the image data for the pages printed in the second and subsequent copies.

(Other embodiments)
In the above-described embodiment, the case of executing the image forming job received via the communication I / F 114 has been described as an example. However, the present invention is not limited to this, and the present embodiment can also be applied to, for example, executing a copy job for copying a manuscript image read through an image reader. It can also be applied to print image data and report information stored in advance in the storage unit 105.

Further, it may be applied to printing facsimile data received from a facsimile machine via a public line.

In the present embodiment, the calculation of the toner loading amount value has been described by taking as an example a mode executed by the CPU. However, the present invention is not limited to this, and can be realized by, for example, a process in which one or more processors in the computer of the system or device reads and executes a program. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

100 Image forming device 101 Controller 102 CPU
103 ROM
104 RAM
105 Storage 113 Printer I / F
114 Communication I / F
115 Printer control unit 122 Printer 124 External device 127 Exposure control unit 128 Fixing control unit 122 Printer 214 RIP unit

Claims (9)

In an image forming apparatus that forms an image on a sheet according to an input image forming job,
A generation means for generating raster image data from the print data of the image formation job, and
A setting means that analyzes the raster image data of the page of interest generated by the generation means and sets the fixing temperature of the page of interest based on the result of the analysis.
An image forming means for forming an image of the page of interest on the image carrier based on the raster image data of the page of interest, and
A transfer means for transferring the image of the page of interest formed on the image carrier to the sheet, and
A fixing means for fixing the image of the page of interest on the sheet,
It has a fixing temperature control means for controlling the fixing temperature for the attention page based on the fixing temperature of the attention page set by the setting means.
The setting means is
When outputting at least one copy of the printed matter, the fixing temperature of N pages from the beginning of the print data of the image forming job is set to a predetermined fixing temperature, and the fixing temperature of the pages after N + 1 is the result of the analysis. set the fixing temperature based on,
When outputting a plurality of printed matter and continuously forming an image of the same page for a specified number of copies, the fixing temperature of the N pages from the beginning and the pages after the N + 1 page is set. An image forming apparatus characterized in that the fixing temperature is set based on the result of the analysis . In an image forming apparatus that forms an image on a sheet according to an input image forming job,
A generation means for generating raster image data from the print data of the image formation job, and
A setting means that analyzes the raster image data of the page of interest generated by the generation means and sets the fixing temperature of the page of interest based on the result of the analysis.
An image forming means for forming an image of the page of interest on the image carrier based on the raster image data of the page of interest, and
A transfer means for transferring the image of the page of interest formed on the image carrier to the sheet, and
A fixing means for fixing the image of the page of interest on the sheet,
It has a fixing temperature control means for controlling the fixing temperature for the attention page based on the fixing temperature of the attention page set by the setting means.
The setting means is
When outputting at least one copy of the printed matter, the fixing temperature of N pages from the beginning of the print data of the image forming job is set to a predetermined fixing temperature, and the fixing temperature of the pages after N + 1 is the result of the analysis. Set the fixing temperature based on
When outputting a plurality of copies of printed matter and the raster image data of the second and subsequent copies of the attention page is not generated, the fixing temperature of the N pages from the beginning and the pages after the N + 1 pages is set. An image forming apparatus characterized in that the fixing temperature is set based on the result of the analysis. The first or second claim is characterized in that, when the image forming job is designated for single-sided printing, the N is 1, and when the image forming job is designated for double-sided printing, the N is 2. The image forming apparatus described. When the image forming of another image forming job executed first in the image forming job is performed, the setting means may be N pages from the beginning of the image formed by the image forming job. The image forming apparatus according to any one of claims 1 to 3 , wherein the fixing temperature is set based on the analysis result of the raster image data of the page of interest. The image formation according to any one of claims 1 to 4 , wherein the predetermined fixing temperature is a temperature at which the maximum toner loading value calculated from the raster image data of the page of interest can be fixed. apparatus. It further has a calculation means for calculating the toner loading value from the raster image data of the attention page.
The image forming apparatus according to any one of claims 1 to 5 , wherein the setting means sets a fixing temperature based on a toner loading value calculated by the calculation means. The image forming apparatus according to claim 6 , wherein the calculation means does not perform a process of calculating a toner loading amount value from the raster image data from the beginning to the Nth page. The calculation means divides the raster image data of the attention page generated by the generation means into a plurality of blocks, and calculates the toner load value of the attention page based on the toner load value of each block. The image forming apparatus according to claim 6 . The image forming apparatus according to any one of claims 1 to 8 , wherein the image forming job is input from an external device communicating with the image forming apparatus.

Images