JP2015003429A - Image formation device, image formation system, control method for image formation device, and control program for image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device of low manufacturing cost, enabling quick image formation.SOLUTION: An image formation device includes a drawing processing part 24, an analyzing processing part 23, and a compression control part 25. The drawing processing part 24 performs drawing processing in band unit based on print data of an object to be processed, for generating printable data. The analyzing processing part 23, prior to the drawing processing, differentiates presence of image in band unit based on the print data. The drawing processing part 24 performs compression instructions for compressing the printable data. The compression control part 25 compresses the printable data in band unit based on the compression instructions. The drawing processing part 24 does not perform compression instructions for a non image band having been differentiated to have no image by the analyzing processing part 23, and performs compression instructions in band unit for a printable data of a band except for the non image band.

Description

  The present invention relates to an image forming apparatus, an image forming system, an image forming apparatus control method, and an image forming apparatus control program, and more particularly, an image forming apparatus that draws and compresses printable data in band units based on print data. The present invention relates to an image forming system, an image forming apparatus control method, and an image forming apparatus control program.

  Examples of the image forming apparatus include a multi function peripheral (MFP) having a scanner function, a facsimile function, a copying function, a printer function, a data communication function, and a server function, a facsimile apparatus, a copying machine, and a printer. As such an image forming apparatus, there is an image forming apparatus that draws and compresses printable data in units of bands based on print data described in a predetermined description language.

  In recent years, printing quality has been improved in drawing processing (PC print control) performed when a print instruction is issued from an external device (such as a personal computer), and drawing at a relatively high resolution (eg, 1200 dpi). Processing is often performed. On the other hand, regarding the hardware configuration of the image forming apparatus, it is effective to save the work memory area of the drawing area in order to reduce the manufacturing cost of the image forming apparatus. In order to save the work memory area while enabling high-resolution rendering processing as described above, it is essential to perform control for performing rendering and compression sequentially for each band.

  The following Patent Document 1 acquires and analyzes information in PDL format, outputs a display list for executing image formation output for each band in which a unit page is divided into a plurality of bits, and a bitmap based on the display list A configuration of an apparatus for generating data is described. In this apparatus, a charge amount is determined for each band depending on whether or not an object is included in each band.

  In Patent Document 2 below, when a plurality of image formations are performed, when image data for the second and subsequent copies is transferred, the white detection result is an invalid band based on the white detection result of the first copy held in the descriptor. For this image data, it is described that a skip notification is issued and only the image data of the effective band of the white detection result is read out.

  Patent Document 3 below describes an image forming apparatus that can provide an image forming output service on a pay-as-you-go basis. The image forming apparatus acquires and analyzes information in the PDL format, outputs a display list for executing image forming output for each band divided into a plurality of unit pages, and generates bitmap data based on the display list. Is generated. It is described that this image forming apparatus determines whether or not an object is included in each band, and determines a charge amount for each band based on the determination result.

  In Patent Document 4 below, in an image processing apparatus, when the display list is analyzed, it is sequentially determined which of the hardware processing time and the software processing time is short according to the characteristics of the display list, and the hardware drawing and the software drawing processing are switched. It is disclosed.

  In Patent Document 5 below, the contents of a display list in print data are analyzed, and scan lines that can be combined into one can be combined into one so that printing can be performed at high speed using a small amount of memory. It is disclosed to try to do.

JP 2012a24667 A JP 2011-042056 A JP 2012a55543 A Japanese Patent Application Laid-Open No. 2011-165022 JP 2002-254731 A

  In the image forming apparatus as described above, it is common to employ a central processing unit (CPU) having a dual core configuration. In the PC print control of the image forming apparatus, the total performance of the image forming apparatus that requires a multi-access operation can be improved by assigning the drawing processing module and the system control module to different cores. Here, the drawing processing module analyzes print data received from an external device, generates a display list, and performs drawing based on the display list. The system control module performs a process of compressing the drawing data and a process of decompressing and printing the compressed data or storing the compressed data in a BOX (storage area) as it is. When the drawing processing module and the system control module are assigned to different cores in this way, it is necessary to reduce the frequency of communication between the two as much as possible and reduce the software load.

  By the way, with respect to general print data normally used in an office, there are few cases where image data is present on the entire surface of one page of an original, and for example, the first and last few bands of each page often have no image. . In addition, depending on the document, there is often a case where an imageless band exists near the center of one page.

  Conventionally, however, the communication control between the drawing processing module and the system control module is generally performed sequentially for drawing and compression for each band. When such control is performed, whether or not the band to be processed is a non-image band is determined after completion of the drawing processing for each band, and if it is a non-image band, information indicating that is sent from the drawing processing module to the system. Notification to the control module in units of bands has been performed. Therefore, there has been a problem that the load of software increases and the performance of the image forming apparatus is hindered.

  Regarding such problems, the above-mentioned Patent Documents 1 to 5 do not disclose effective solutions.

  The present invention has been made to solve such problems. An image forming apparatus, an image forming system, an image forming apparatus control method, and an image forming apparatus capable of forming an image quickly and at a low manufacturing cost. The purpose is to provide a control program.

  In order to achieve the above object, according to one aspect of the present invention, an image forming apparatus generates a printable data by performing drawing processing for each band based on print data to be processed, and compresses the printable data A drawing processing unit that performs a compression instruction, a determination unit that determines presence / absence of an image in band units based on print data, and printable data in band units based on a compression instruction by the drawing processing unit prior to drawing processing A compression control unit that compresses the image in a band, and the rendering processing unit does not issue a compression instruction for a non-image band that is determined to have no image by the determination unit, and prints data in a band unit for printable data of bands other than the non-image band Instruct compression.

  Preferably, the determination unit performs the first processing mode drawn on the paper without rotation based on the print data prior to the drawing processing, and the paper is 90 degrees or 270 degrees from the first processing mode. For each of the second processing modes drawn by rotation, the print data for image formation for one page is compressed based on the number of imageless bands and the bandwidth determined that there is no image. The drawing processing unit performs the drawing process in the processing mode with the shorter processing time calculated by the determination unit.

  According to another aspect of the present invention, the image forming apparatus performs drawing processing for each band based on the print data to be processed, generates printable data, and issues a compression instruction for compressing the printable data. Prior to drawing processing, a drawing processing unit, a determination unit for determining presence / absence of an image in band units based on print data, and compression control for compressing printable data in band units based on a compression instruction from the drawing processing unit The discriminating unit applies the first processing mode drawn without rotation to the paper based on the print data prior to the drawing processing, and the paper is only 90 degrees or 270 degrees from the first processing mode. One page based on the number of non-image bands and the bandwidth determined that there is no image for each of the second processing modes that are rotated and drawn For print data for image formation by calculating a processing time required to perform the compression, the drawing processing unit is a processing mode towards shorter processing time calculated by the determination unit, performing a drawing process.

  Preferably, the determination unit collectively determines a no-image band for the page before first instructing compression for print data for image formation for one page, and the compression control unit determines the print data. Before performing the compression for the first time, the information of the no-image band determined at once is acquired.

  Preferably, the image forming apparatus further includes an analysis processing unit that analyzes the print data and generates a display list, and the drawing processing unit generates printable data based on the display list generated by the analysis processing unit. .

  Preferably, the image forming apparatus is configured using a control circuit having at least two cores of the central processing unit, and the drawing processing unit functions based on the operation of the first core of at least two cores. The compression control unit functions based on the operation of the second core different from the first core among the at least two cores.

  Preferably, the drawing processing unit reduces the number of compression instructions from the drawing processing unit to the compression control unit in accordance with a determination result by the determination unit.

  According to still another aspect of the present invention, an image forming system having an image forming apparatus and an external device that transmits print data to be processed to the image forming apparatus. The external device transmits the print data to the image forming apparatus. The image forming apparatus includes a discriminating unit that discriminates whether or not there is an image in a band unit of print data for image formation for one page, and the image forming apparatus performs band unit based on the print data transmitted from the external device To generate printable data, and compress the printable data in band units based on a drawing processing unit that gives a compression instruction for compressing the printable data and a compression instruction from the drawing processing unit. A compression control unit, and the drawing processing unit does not issue a compression instruction for a non-image band determined to have no image by the determination unit; For printable data of the band except image band, performs compression instruction in band units.

  Preferably, the determination unit collectively determines a non-image band for print data for image formation for one page, and the compression control unit is collectively determined before the print data is first compressed. Acquire information on non-image bands.

  Preferably, the image forming apparatus further includes an analysis processing unit that analyzes the print data and generates a display list, and the drawing processing unit generates printable data based on the display list generated by the analysis processing unit. .

  Preferably, the image forming apparatus is configured using a control circuit having at least two cores of the central processing unit, and the drawing processing unit functions based on the operation of the first core of at least two cores. The compression control unit functions based on the operation of the second core different from the first core among the at least two cores.

  Preferably, the drawing processing unit reduces the number of compression instructions from the drawing processing unit to the compression control unit in accordance with a determination result by the determination unit.

  According to still another aspect of the present invention, a method for controlling an image forming apparatus generates a printable data by performing drawing processing on a band basis based on print data to be processed, and compresses the printable data. Prior to the drawing process, a drawing process step for performing a compression instruction, a determination step for determining the presence or absence of an image in band units based on the print data, and printable data in band units based on the compression instruction in the drawing process step. A compression control step for compressing, and the drawing processing step does not issue a compression instruction for a non-image band determined to have no image in the determination step, and printable data of bands other than the non-image band in band units. Instruct compression.

  According to still another aspect of the present invention, a method for controlling an image forming apparatus generates a printable data by performing drawing processing on a band basis based on print data to be processed, and compresses the printable data. Prior to the drawing process, a drawing process step for performing a compression instruction, a determination step for determining the presence or absence of an image in band units based on the print data, and printable data in band units based on the compression instruction in the drawing process step. A compression control step for compressing, and the determination step includes a first processing mode in which drawing is performed on the paper without rotation based on the print data, and 90 degrees or 270 from the first processing mode, prior to the drawing process. For each of the second processing modes drawn by rotating with respect to the paper for each time, it is determined that there is no image. Based on the number of image bands and the bandwidth, the processing time required to compress the print data for image formation for one page is calculated. The drawing processing step calculates the processing time calculated in the determination step. The drawing process is performed in the shorter processing mode.

  According to still another aspect of the present invention, a control program for an image forming apparatus generates printable data by performing drawing processing for each band based on print data to be processed, and compresses the printable data. Prior to the drawing process, a drawing process step for performing a compression instruction, a determination step for determining the presence or absence of an image in band units based on the print data, and printable data in band units based on the compression instruction in the drawing process step. A compression control step for compressing, and the drawing processing step does not issue a compression instruction for the non-image band determined to have no image by the determination step, and printable data of the band excluding the non-image band, Instructs compression in band units.

  According to still another aspect of the present invention, a control program for an image forming apparatus generates printable data by performing drawing processing for each band based on print data to be processed, and compresses the printable data. Prior to the drawing process, a drawing process step for performing a compression instruction, a determination step for determining the presence or absence of an image in band units based on the print data, and printable data in band units based on the compression instruction in the drawing process step. A compression control step for compression is executed by the computer, and the determination step includes a first processing mode in which drawing is performed without rotation on the paper based on the print data, and the first processing mode to 90 from the first processing mode. Or each of the second processing modes drawn by rotating with respect to the sheet by 270 degrees, Based on the number of non-image bands determined to have no image and the bandwidth, the processing time required to compress print data for image formation for one page is calculated. The drawing process is performed in the processing mode with the shorter processing time calculated in the step.

  According to still another aspect of the present invention, the control program of the image forming apparatus used in the image forming system having the image forming apparatus and the external apparatus that transmits print data to be processed to the image forming apparatus is The image forming apparatus includes a determination unit that determines whether or not there is an image in a band unit of print data for image formation for one page before transmitting the print data to the image forming apparatus. Based on the print data transmitted from the device, drawing processing is performed in band units to generate printable data, and a drawing processing step for giving a compression instruction for compressing the printable data, and a compression instruction by the drawing processing step And a compression control step for compressing printable data on a band basis. , Drawing processing step, without compression instruction for solid image band is determined that there is no image by determining step, the printable data of the band with the exception of no image band, performs compression instruction in band units.

  According to these inventions, it is possible to provide an image forming apparatus, an image forming system, an image forming apparatus control method, and an image forming apparatus control program that can form an image quickly and are low in manufacturing cost.

1 is a front view showing an image forming apparatus in one embodiment of the present invention. 2 is a block diagram illustrating a configuration of a control circuit unit of the image forming apparatus. FIG. It is a control block diagram regarding the control which a control circuit part performs. It is a figure which shows operation | movement of the control circuit part when a PC print job is performed in this Embodiment. It is a 1st flowchart which shows operation | movement of an analysis process part. It is a 2nd flowchart which shows operation | movement of an analysis process part. It is a flowchart which shows operation | movement of a drawing process part. It is a 1st flowchart which shows operation | movement of a compression control part. It is a 2nd flowchart which shows operation | movement of a compression control part. It is a figure which shows an example of the image which a non-image band exists in the head, the center, and the rear end in 1 page. It is a figure which shows the specific example of the sequence of a comparative example with respect to this Embodiment, and processing time. It is a figure which shows the specific example of the sequence and processing time of this Embodiment. It is a figure which shows an example of the process aspect in the case of drawing the print data transmitted from the external apparatus without rotation. FIG. 14 is a diagram illustrating an example of a processing mode when the print data illustrated in FIG. 13 is drawn with rotation. It is a figure which shows the processing time per page in the case of "no rotation". It is a figure which shows the processing time per page in the case of "with rotation". 6 is a flowchart illustrating an operation of an analysis processing unit of the image forming apparatus according to a variation of the embodiment of the present invention.

  Hereinafter, an example of an image forming apparatus according to an embodiment of the present invention will be described.

  The image forming apparatus is an MFP (Multi Function Peripheral) having a scanner function, a copying function, a printer function, a facsimile function, a data communication function, and a server function. In the scanner function, an image of a set original is read and stored in an HDD (Hard Disk Drive) or the like. In the copying function, it is further printed (printed) on paper or the like. In the function as a printer, when a print instruction is received from an external terminal such as a PC (personal computer), printing is performed on a sheet based on the instruction. In the facsimile function, facsimile data is received from an external facsimile machine and stored in an HDD or the like. In the data communication function, data is transmitted / received to / from a connected external device. In the server function, a plurality of users can share data stored in the HDD or the like.

  The image forming apparatus constitutes an image forming system together with an external device (such as a PC). In the image forming system, print data to be processed is transmitted from an external device to the image forming apparatus. The image forming apparatus forms an image based on the transmitted print data (PC print job).

  [Embodiment]

  First, a hardware configuration of an image forming apparatus according to one embodiment of the present invention will be described.

  [Configuration of Image Forming Apparatus]

  FIG. 1 is a front view showing an image forming apparatus according to one embodiment of the present invention.

  As shown in FIG. 1, the image forming apparatus 1 includes an image forming unit 3, an image reading unit 5, a paper feeding unit 90, a paper discharging unit 91, a control circuit 50, and the like.

  The image forming unit 3 includes, for example, a toner image forming unit (not shown), a paper transport unit (not shown), and a fixing device (not shown), and forms an image on a paper by an electrophotographic method. To do. The sheet is conveyed from the sheet feeding unit 90 to the toner image forming unit by the sheet conveying unit. The paper on which the image is formed by the toner image forming unit and the fixing device is discharged to the paper discharge unit 91 by the paper transport unit. The image forming unit 3 forms an image on a sheet based on the image subjected to image processing by the control circuit unit 50. The image forming unit 3 is configured to be able to form a color image on a sheet by synthesizing four color images by a so-called tandem method.

  The image reading unit 5 is disposed on the upper part of the housing of the image forming apparatus 1. The image reading unit 5 includes an ADF (Auto Document Feeder) 5a. The image reading unit 5 performs the above-described scanner function. The image reading unit 5 scans a document placed on a transparent document table with a contact image sensor and reads it as image data. Further, the image reading unit 5 reads the image data by the contact image sensor while sequentially taking in a plurality of documents set on the document tray by the ADF 5a. The image data read by the image reading unit 5 is converted into data of a predetermined data format by the control circuit unit 50 and stored in a storage device or the like provided inside the control circuit unit 50.

  FIG. 2 is a block diagram illustrating a configuration of the control circuit unit 50 of the image forming apparatus 1.

  The control circuit unit 50 is connected to the image forming unit 3 and the image reading unit 5 in the image forming apparatus 1. The control circuit unit 50 is connected to the image reading unit 5 via an IR image interface (I / F) 41. The control circuit unit 50 is connected to the image forming unit 3 via the printer image interface 42. The IR image interface 41 is connected to the bus arbiter 13 via the input memory 43. The printer image interface 42 is connected to the bus arbiter 13 via the output memory 44.

  The control circuit unit 50 is connected to the operation panel 45 of the image forming apparatus 1. As a result, the control circuit unit 50 executes various controls in accordance with user instructions received via the operation panel 45. The operation panel 45 is connected to the first CPU 12a.

  The control circuit unit 50 is connected to a network such as a local information communication network (LAN) via the network adapter 17. Accordingly, the image forming apparatus 1 can communicate with an external device (for example, a personal computer (PC)) 500 connected to the network via the network. The network adapter 17 is controlled by the network controller 18. The network controller 18 is connected to the memory controller PCI bridge 14 via a PCI bus inside the control circuit unit 50.

  In the present embodiment, the control circuit unit 50 is configured by using a CPU 12 (first CPU 12a, second CPU 12b) having an AMP (Asymmetric Multiple Processor (Processing)) configuration. The control circuit unit 50 includes a memory controller PCI bridge 14, a first CPU 12a, a second CPU 12b, a first work memory 16a, a second work memory 16b, and a shared work memory 16c. The first CPU 12a, the first work memory 16a, and the shared work memory 16c are connected to the memory controller PCI bridge 14. The first CPU 12a and the second CPU 12b are connected via a shared work memory 16c. The shared work memory 16c is a memory used in common by the first CPU 12a and the second CPU 12b. The second work memory 16b is used by the second CPU 12b.

  The memory controller PCI bridge 14 is connected to a flash ROM (an example of a storage device) 20. The flash ROM 20 stores a control program 20a for operating the image forming apparatus 1. When the image forming apparatus 1 is powered on, the control circuit unit 50 loads the control program 20a from the flash ROM 20 onto the shared work memory 16c. The CPU 12 controls the operation of the image forming apparatus 1 by performing control based on the loaded control program 20a.

  The memory controller PCI bridge 14 is connected to the bus arbiter 13 via the PCI bus. The bus arbiter 13 includes a transfer control unit 13 a and controls data transfer with the image forming unit 3 and the image reading unit 5. The bus arbiter 13 is connected to the file memory 15 via the compression / decompression control unit 11. The compression / expansion control unit 11 includes a plurality of compression / expansion devices. Each of the plurality of compression / decompression devices can perform either a compression operation or an expansion operation.

  [Description of Operation of Image Forming Apparatus]

  The image forming apparatus 1 causes the image forming unit 3 to print a job (PC print job) in which an image is formed and output by the image forming unit 3 based on an instruction from the external device 500 or a document read using the image reading unit 5. It is possible to perform a job (copy job) to be copied by using. These jobs are executed by performing image input and image output as follows, for example.

  When an image is input in a PC print job, it is as follows. That is, the external device (such as a PC) 500 uses a printer driver to convert an arbitrary file designated as a print target by the user into page description language data, and creates print data. The external device 500 transmits print data to the image forming apparatus 1 via a communication network. The print data is transmitted from the external device 500 to the network controller 18 via the network adapter 17. The control circuit unit 50 analyzes the print data by software processing and draws an image in the shared work memory 16c. The drawing data (image) obtained by drawing is transferred to the compression / decompression control unit 11 via the memory controller PCI bridge 14 and the bus arbiter 13. In the compression / decompression control unit 11, drawing data is compressed by a designated compression / decompression unit, and the generated compressed data is stored in the file memory 15. An image is input by repeating the above operation for the required number of pages.

  The case where image output is performed in a PC print job is as follows. That is, the input compressed data is read from the file memory 15, transferred to the compression / decompression control unit 11, and decompression is performed by the compression / decompression device designated here. The decompressed data (image) is output to the image forming unit 3 via the bus arbiter 13, the output memory 4, and the printer image interface 42. The above operation is repeatedly executed by the necessary number of pages for each band of pages to be output, thereby performing image output.

  When image input is performed in a copy job, it is as follows. That is, the image data read by the image reading unit 5 is input from the IR image interface 41 to the control circuit unit 50 and temporarily stored in the input memory 43. The image data is transferred from the input memory 43 to the compression / decompression control unit 11 via the bus arbiter 13. Here, the compression operation of the image data is performed by the designated compression / decompression unit, and the generated compressed data is stored in the file memory 15. The above operation is repeatedly executed for the number of read pages, thereby inputting an image.

  When image output is performed by a copy job, an operation similar to the image output performed by the above-described PC print job is performed.

  FIG. 3 is a control block diagram relating to the control performed by the control circuit unit 50.

  As shown in FIG. 3, the control circuit unit 50 executes the control program 20 a to configure the following control block and control the operation of the image forming apparatus 1.

  That is, the control circuit unit 50 includes a job management unit 21, a network management unit 22, an analysis processing unit 23, a drawing processing unit 24, a compression control unit 25, an IR image interface control unit 26, and an operation panel control unit. 27, an expansion control unit 28, and a printer interface control unit 29.

  The operation panel control unit 27 performs display and input processing on the operation panel 45. The network management unit 22 manages network transmission / reception. The job management unit 21 starts a job in response to an instruction from the operation panel 45 and a start request from the network, and controls the job after the start.

  The analysis processing unit 23 analyzes print data transmitted from an external device 500 such as a PC in a PC print job, and generates a display list. The drawing processing unit 24 performs drawing processing based on the generated display list. The compression control unit 25 performs a compression control in response to a request from the drawing processing unit 24. The IR image interface control unit 26 performs image input control from the image reading unit 5. The decompression control unit 28 performs decompression control of the image data once compressed at the time of printing. The printer control unit 29 controls the printer image interface 42.

  In the present embodiment, a CPU 12 using a dual configuration is employed, and the software processing load is equally allocated. That is, the analysis processing unit 23 and the drawing processing unit 24 are assigned to the second CPU 12b. In addition, other system control processes such as the compression control unit 25, the network management unit 22, and the job management unit 21 are assigned to the first CPU 12a, and the exchange of information between the first CPU 12a and the second CPU 12b is performed in the shared work memory. 16c.

  [Specific example of operation during execution of PC print job]

  FIG. 4 is a diagram illustrating an operation of the control circuit unit 50 when a PC print job is executed in the present embodiment.

  As shown in FIG. 4, when a PC print job is executed, the control circuit unit 50 performs the following operation.

  First, the external device 500 uses a printer driver to convert an arbitrary file designated by the user into a page description language, create print data, and transmit the print data to the image forming apparatus 1 via the network. When the print data is transmitted, the image forming apparatus 1 receives the print data by the network management unit 22. The network management unit 22 notifies the analysis processing unit 23 of the received print data by sequentially performing inter-CPU communication. That is, print data is sent from the first CPU 12a to the second CPU 12b.

  In the second CPU 12b, the analysis processing unit 23 performs language analysis (page analysis) on the input print data. At this time, first, at the head of each page, it is determined whether an image exists for each band for both “no rotation” and “with rotation”. Then, as will be described later, the processing time per page is calculated, and information regarding the bandwidth, information regarding the number of bands, and no-image band information are notified to the drawing processing unit 24. Here, the non-image band information refers to information such as the number of a band without an image. “No rotation” refers to a processing mode in which print data is drawn on the paper in the same direction without rotation and printed on the paper. “With rotation” refers to a processing mode in which drawing is performed by rotating around an axis perpendicular to the paper surface of the sheet by 90 degrees or 270 degrees from “without rotation”. Whether to print with “no rotation” or “with rotation” can be determined by the judgment of the control circuit unit 50 if there is no instruction from the user.

  When such information is notified, the drawing processing unit 24 notifies the compression control unit 25 of no-image band information at the head of the page. Further, returning to the processing of the analysis processing unit 23, the display list (DL) 30 which is an intermediate language is sequentially generated and stored in the work memory 16b sequentially. The drawing processing unit 24 reads the display list 30 from the work memory 16 b and executes software processing (rasterization) based on the display list 30. As a result, printable data 31 is generated in 256-line band units and in YMCK color units. The generated printable data 31 is stored in the shared work memory 16c. When the printable data for one band is stored in the shared work memory 16c, the drawing processing unit 24 transmits a compression request for the printable data 31 to the compression control unit 25 by inter-CPU communication. That is, a compression request is transmitted from the second CPU 12b to the first CPU 12a.

  In the first CPU 12a, when the compression control unit 25 receives a compression request, the compression control unit 25 performs a compression process in band units. The compressed data generated by the compression process is sequentially stored in the file memory 15. The compressed data stored in the file memory 15 is expanded by the expansion control unit 28 at the printing timing. The decompressed data is transmitted to the image forming unit 3 via the printer image interface 42, and a printing operation is performed.

  Processing in each of the analysis processing unit 23, the drawing processing unit 24, and the compression control unit 25 when such an operation is performed will be described below with reference to flowcharts.

  FIG. 5 is a first flowchart showing the operation of the analysis processing unit 23. FIG. 6 is a second flowchart showing the operation of the analysis processing unit 23.

  The analysis processing unit 23 performs display list generation processing and determination processing as to whether or not it is an imageless band as follows. That is, as shown in FIG. 5, in step S101, initialization processing of variables and the like necessary for analysis processing is performed.

  In step S <b> 103, the analysis processing unit 23 acquires print data for one page to be processed, which is notified from the network management unit 22.

  In step S105, the analysis processing unit 23 determines whether an image exists in each band based on the drawing position of the print data in the case of “no rotation”.

  In step S107, the analysis processing unit 23 assigns each band based on the print data drawing position in the case of “with rotation” (when the main scanning direction and the sub-scanning direction are switched by 90 degrees or 270 degrees). It is determined whether an image exists.

  In step S109, based on the determination result in step S105 and the determination result in step S107, the processing time for one page is calculated for each of “without rotation” and “with rotation”. The processing time can be calculated based on the number of non-image bands.

  In step S111, the processing time at “no rotation” is compared with the processing time at “with rotation”, and it is determined whether or not “no rotation” is faster (whether the processing time is short). .

  If “no rotation” is faster in step S111, it is determined to print “no rotation” in step S113. That is, the bandwidth is the length in the main scanning direction, and the display list creation mode is “no rotation”.

  On the other hand, if “no rotation” is not faster in step S111, it is determined in step S115 to print “rotation”. That is, the bandwidth is the length in the sub-scanning direction, and the display list creation mode is “with rotation”.

  As shown in FIG. 6, in step S <b> 121, the analysis processing unit 23 notifies the drawing processing unit 24 of the bandwidth, the number of bands, and no image band information.

  In step S123, the analysis processing unit 23 acquires print data for one page to be processed again.

  In step S125, the analysis processing unit 23 actually creates a display list according to the bandwidth determined in step S113 or step S115 and the presence / absence of rotation. The created display list is stored in the second work memory 16b.

  In step S127, the analysis processing unit 23 repeatedly performs display list generation processing until generation of a display list for one page is completed. When the generation of the display list for one page is completed, the process returns to step S103 to continue the process for the next page.

  Here, the display list stored in the second work memory 16b is read by the drawing processing unit 24, and a drawing process for rasterizing the drawing area in units of bands is performed, and the drawing data is written in the shared work memory 16c. When drawing of one band is completed for a band with an image (a band other than a non-image band), the drawing processing unit 24 transmits a compression request (compression start notification) to the compression control unit 25.

  FIG. 7 is a flowchart showing the operation of the drawing processing unit 24.

  As illustrated in FIG. 7, in step S <b> 201, the drawing processing unit 24 starts processing the target page.

  In step S203, the drawing processing unit 24 notifies the compression control unit 25 of the bandwidth, the number of bands, and no image band information.

  In step S205, the drawing processing unit 24 performs drawing processing for each band and each color using the display list (rasterization). The generated printable data is stored in the shared work memory 16c.

  In step S207, if the image has a certain band, the drawing processing unit 24 makes a compression request for the printable data after the drawing process.

  In step S <b> 211, the drawing processing unit 24 stands by until a compression completion notification is received from the compression control unit 25.

  In step S213, it is determined whether or not the drawing process for the data for one page of the target page has ended. Until the drawing process is completed, the processes from step S205 are repeated.

  If it is determined in step S213 that the drawing process has been completed, the drawing processing unit 24 determines in step S215 whether or not processing for all pages has been completed. If the processing for all pages has not been completed, the processing from step S201 is performed once again. If all the pages have been processed, a series of processing ends.

  FIG. 8 is a first flowchart showing the operation of the compression control unit 25. FIG. 9 is a second flowchart showing the operation of the compression control unit 25.

  As shown in FIG. 8, in step S301, the compression control unit 25 starts processing the target page.

  In step S <b> 303, the compression control unit 25 receives a notification regarding the bandwidth, the number of bands, and the non-image band information from the drawing processing unit 24.

  In step S <b> 305, the compression control unit 25 waits until a compression request is sent from the drawing processing unit 24.

  When there is a compression request in step S305, in step S307, the compression control unit 25 determines whether the processing target band is a non-image band.

  If it is a non-image band in step S307, a non-image compression process is performed in step S309. That is, for example, compression is performed on data of a non-image band prepared in advance. When compression is performed, the next band is set as a processing target, and the process returns to step S307.

  If it is not an imageless band in step S307, the band image is compressed in step S311 as shown in FIG. That is, the compression control unit 25 reads the printable data for each band from the shared work memory 16c and compresses it. The generated compressed data is stored in the file memory 15.

  In step S313, the compression control unit 25 notifies the completion of compression.

  In step S315, the compression control unit 25 determines whether or not the process for the page to be processed has been completed. If not completed, the process returns to step S305.

  When the processing of the target page is completed in step S315, the compression control unit 25 notifies the analysis processing unit 23 of the fact in step S317.

  In step S319, the compression control unit 25 determines whether all pages have been processed. If it has been completed, the process ends. If not completed, the process returns to step S301.

  [Description of First Specific Example of Each Process]

  Next, a first specific example of actual analysis processing, drawing processing, and compression processing will be described.

  FIG. 10 is a diagram illustrating an example of an image in which a non-image band exists at the head, center, and rear end in one page.

  FIG. 10 illustrates an example of band division and the number of lines when control is performed to receive print data having a 1200 dpi A4Lef (Long Edge Feed) size from the external device 500 and expand it in band units. In FIG. 10 (the same applies to the following similar figures), a large rectangular frame indicates a print image corresponding to the print data, and a hatched area with a narrow interval indicates a non-image band. A wide hatched area in the print image indicates a pasted image pasted in the print image, and a character string indicated by “*” or the like in the print image is in the print image. Indicates a character string. A long and narrow area indicated by a thin line segment in a printed image is a band. A band that does not include a character string or pasted image is a no-image band.

  The band division mode and the number of lines in the sub-scanning direction are obtained by the following calculation. In the present embodiment, the size of the drawing area existing in the shared work memory 16c will be described as follows using multi-valued data of 1200 dpi YMCK A4Lef size.

  (Number of dots in the main scanning direction) = 297 (mm) /25.4 (dot / mm) * 1200 (dpi) = 14031 (dot)

  (Number of lines in the sub-scanning direction) = 210 (mm) /25.4 (dot / mm) * 1200 (dpi) = 9921 (line)

  (Required data size for one page) = (number of dots in the main scanning direction) × (number of lines in the sub scanning direction) × 4 (color) = about 531 (MByte)

  In this embodiment, in order to save memory capacity, the necessary data size for one page is not provided for the entire page, but the drawing data is divided into band units with 256 lines as one band. Handle. That is, if the A4Lef size is used, control is performed by dividing 256 pages into one band and dividing one page into 39 bands in the sub-scanning direction.

  Here, the size of the drawing shared work memory 16c or the like needs to be provided as long as it can store at least two bands. This is because it is necessary to be able to execute the drawing process for the next band in parallel during the compression process for the previous band. Therefore, in this embodiment, for example, a capacity for two bands is secured. The capacity may be larger than this.

  Assuming that the length in the main scanning direction is rounded up in units of 256 dots for the actual size calculation, the capacity of the shared work memory 16c can be saved up to the following capacity by dividing the band in this way.

  256 (line) × 256 (dot) × 55 (block) × 2 (band) × 4 (color) = about 27.5 (MByte)

  First, the analysis processing unit 23 analyzes only the coordinate information of the print data in advance, and determines a band where there is no image. For example, in the example shown in FIG. 10, a total of 8 bands including 1 to 3 from the top, 26 and 27 at the center, and 37 to 39 at the rear end (all band numbers counted from the top of the page) are non-images. That is, each of the band numbers 1 to 3, 26, 27, and 37 to 39 is an imageless band.

  An example of processing performed when a PC print job is executed for print data including an imageless band as shown in FIG. 10 will be described together with a comparative example.

  FIG. 11 is a diagram illustrating a specific example of a sequence and processing time of a comparative example with respect to the present embodiment.

  In FIG. 11, unlike the present embodiment, an example is shown in which the analysis processing unit does not determine whether the band is an imageless band. That is, since the processing after discriminating the no-image band as in the present embodiment is not performed in advance, the first to third bands at the top of the page are sequentially supplied to the compression control unit. A compression request for “no image” is issued. That is, for each non-image band, the reception of the compression request from the drawing processing unit, the actual compression process, and the compression completion notification are performed sequentially. In the fourth band, since an image exists, a compression request is issued with an image specified. Thereafter, control is performed by determining whether or not each image is a non-image band until the last band of the page.

  In the process of the comparative example, the processing time required for each stage of the process is, for example, as follows.

  The processing time by communication between CPUs is 2 ms, for example. This is because a dual-core CPU is used, and the analysis processing and drawing processing modules and the system control module including compression control are controlled by separate cores, and communication between the two takes time. It is. When communication between the CPUs 12 occurs, it takes about 2 ms in actual measurement values.

  The processing time for the compression processing time (with images) is, for example, 20 ms. This is YMCK multi-valued four colors, and when the image actually exists in the main scanning width 14031 (dot) of 1200 dpi and the number of sub-scanning lines of 256 lines, the time required for compression processing by hardware is about 20 ms. take time.

  The processing time for the compression processing time (no image) is, for example, 4 ms. In the case where an image does not actually exist in the main scanning width 14031 (dot) of 1200 dpi and the number of sub-scanning lines of 256 lines, compression control of actually drawn data is not necessary, and a prepared non-image (white data) ) Is simply transferred to the file memory. Therefore, the processing is completed in a shorter time compared to the case where an actual image is compressed as in the case where there is an image. This is also calculated from the actual measurement value of the hardware performance in this embodiment.

  As shown in FIG. 11, when processing the individual processing times for the above-mentioned print data using the conventional technique, the processing time is calculated by summing the time for each processing for one page, for example, 946 ms. Become.

  FIG. 12 is a diagram illustrating a specific example of the sequence and processing time of the present embodiment.

  In this embodiment, before performing analysis processing or drawing processing for one page, the analysis processing unit 23 determines in advance whether or not it is a non-image band. Based on the determination result, the drawing processing unit 24 instructs the compression control unit 25. As a result, the processing for the non-image band in one page is collectively performed at the top of the page. In other words, the compression control unit 25 that has received the instruction registers the information of the non-image band for one page in the table, and when a compression request (with image) is received from the drawing processing unit 24, the compression control unit 25 receives no information before that. If there is a band to be processed in the image band, the compression control for the non-image is automatically performed.

  Here, the time required for the notification sequence of the leading non-image band is the same as the normal compression request between CPUs (for example, 2 ms). At this time, in the case where the information is notified at the head of the page for the non-image band, the total processing time for one page is calculated to obtain the processing time, for example, 820 ms. Therefore, compared with the comparative example as shown in FIG. 11, the processing time is shortened by about 10%, and the performance can be improved.

  In the above-described example, the case where there are a total of 8 non-image bands is described. However, if there are 8 or more non-image bands, naturally, the effect of improving the performance is increased accordingly.

  In addition, the processing mode in which the processing time is shortened between “no rotation” and “with rotation” is adopted. However, in this example, the processing time shown in FIG. A processing mode is adopted. The description of the comparison of the processing time between the case of “without rotation” and the case of “with rotation” is omitted here.

  [Description of Second Specific Example of Each Process]

  Next, a second specific example of actual analysis processing, drawing processing, and compression processing will be described.

  FIG. 13 is a diagram illustrating an example of a processing mode when the print data transmitted from the external device 500 is drawn without rotation.

  As shown in FIG. 13, when print data is transmitted, the processing time is calculated based on “no rotation” and “with rotation”, and it is determined which processing mode is adopted. FIG. 13 shows a processing mode of an A4Lef size image of 1200 dpi in the case of “no rotation”. If the print data is drawn as it is, no image band exists.

  FIG. 14 is a diagram illustrating an example of a processing mode when the print data illustrated in FIG. 13 is drawn with rotation.

  As shown in FIG. 14, in this print data, when “with rotation”, there are a plurality of non-image bands. That is, the non-image bands in this case are 1 to 5, 27 to 33, and 50 to 55.

  Next, a method for calculating the processing time per page in the case of “no rotation” will be described.

  FIG. 15 is a diagram showing the processing time per page in the case of “no rotation”.

  The following specific values are the same as those described with reference to FIG. That is, the calculation method is as follows.

  Let T_CompNonRot1 be the compression processing time per band when “no rotation” and “image”. The inter-CPU communication time (sequence processing time) per band is T_Seq. The compression processing time per band when “no rotation” and “no image” is T_CompNonRot2. The number of non-image bands is N_NoImageNonRot. Note that the total number of bands at the time of “no rotation” is 39 because 256 lines are calculated as one band at 1200 dpi of A4Lef.

  When the processing time T_NonRotate per page when “no rotation” is calculated using such a variable, the following equation is obtained.

  T_NonRotate = (T_CompNonRot1 + T_Seq) * (39−N_NoImageNonRot) + T_CompNonRot2 * N_NoImageNonRot

  FIG. 16 is a diagram illustrating a processing time per page in the case of “with rotation”.

  Compared with the description of the values shown in FIG. 15, the rotation changes as follows. That is, since the bandwidth is 0.7 times that of “no rotation”, the processing time is also 0.7 times. Further, by rotating, the number of bands becomes 1.4 times from 39 bands to 55 bands. Therefore, the calculation method is as follows.

  Let T_CompRot1 be the compression processing time per band when “no rotation” and “with image”. The inter-CPU communication time (sequence processing time) per band is T_Seq. The compression processing time per band when “no rotation” or “no image” is T_CompRot2. Let N_NoImageRot be the number of non-image bands. Note that the total number of bands at “no rotation” is 55 because the calculation is performed with 256 lines as one band at 1200 dpi of A4Sef.

  If the processing time T_Rotate per page when “with rotation” is calculated using such variables, the following equation is obtained.

  T_Rotate = (T_CompRot1 + T_Seq) * (55−N_NoImageRot) + T_CompRot2 * N_NoImageRot

  In this way, the processing mode in which the processing time is shortened can be determined based on the processing time T_Rotate and T_NonRotate that can be calculated. For example, in this example, the processing time is shorter for 877 ms for “with rotation” than for 960 ms for “without rotation”. Therefore, as shown in FIG. 16, the process is performed with “with rotation”.

  [Effects of the embodiment]

  In the AMP configuration, each of the first CPU 12a and the second CPU 12b operates and executes an OS (operating system) independently. For this reason, the software processing speed in each of the CPUs 12a and 12b is improved. However, when communication is performed between the CPUs 12a and 12b, it takes time because communication and synchronization control between the CPUs are performed using the shared work memory 16c. Therefore, particularly when the control circuit unit 50 having such an AMP configuration is employed, it is important to reduce the number of communication between CPUs and increase the processing speed.

  In this regard, as described above, in the present embodiment, when a PC print job is performed, image analysis is performed in band units prior to drawing processing of printable data when analyzing print data in a page description language. The presence / absence of necessity (whether it is a no-image band) is determined. The determination regarding the non-image band is performed before the drawing process for the print data for one page, and the software control sequence regarding the subsequent drawing process, transfer, and compression process control is changed according to the determination result. Therefore, it is possible to reduce the load of software processing when a PC print job is performed, and the performance of the image forming apparatus 1 is improved.

  Specifically, in this embodiment, prior to the generation of the display list, the analysis processing unit 23 determines the presence / absence of an image for each band, and no compression request instruction is given for a non-image band. Therefore, the number of repeated compression request instructions from the drawing processing unit 24 to the compression control unit 25 is reduced, and the software processing load is reduced. In particular, in multi-access control performed when a PC print job, a copy job, a scan transmission job, and the like are simultaneously executed in the image forming apparatus 1, it is possible to effectively prevent a decrease in performance.

  Prior to the generation of the display list, the rotation angle is selected to be “no rotation” or “with rotation” by determining the total processing time for one page. Therefore, the processing time per page can be surely shortened, and the performance can be improved.

  [Description of variant]

  FIG. 17 is a flowchart showing the operation of the analysis processing unit 23 of the image forming apparatus 1 according to a variation of the embodiment of the present invention.

  In the above-described embodiment, the analysis processing unit 23 of the image forming apparatus 1 makes a determination regarding the non-image band based on the print data. This determination is made before the external device is transmitted to the image forming apparatus 1. 500 may be performed. In this case, the image forming apparatus 1 may generate printable data and the like thereafter as described above based on the determination result sent from the external device 500 and the non-image band information.

  FIG. 17 shows an operation performed in place of the operation shown in FIG. 5 in the above-described embodiment. That is, first, in step S601, initialization processing for variables and the like necessary for analysis is performed.

  Next, in step S <b> 603, the analysis processing unit 23 acquires information on a non-image band notified via the network management unit 22. This non-image band information is, for example, the result of determining the presence or absence of an image for each band by dividing the area of one page in units of 256 lines in advance when generating print data in a printer driver of an external device 500 such as a PC. It is.

  When the non-image band information is acquired, the processing after step S121 in FIG. 6 is performed. That is, the analysis processing unit 23 notifies the drawing processing unit 24 of the bandwidth, the number of bands, and the non-image band information, and the subsequent processing is performed.

  By such processing, it is possible to improve the performance of the image forming apparatus 1 without the analysis processing unit 23 in the image forming apparatus 1 determining the non-image band region.

  [Others]

  The image forming apparatus 1 may be configured by combining or partially omitting the individual features of the above-described embodiments and modifications. For example, when a PC print job is executed, the processing time may not be compared in advance with “no rotation” and “with rotation”, and the processing may always be performed in one of the modes. . In addition, when the PC print job is executed, the processing time is compared in advance between “no rotation” and “with rotation” at the end without notifying the compression control unit of no image band information. The processing may be performed in a processing mode with a shorter processing time.

  The image forming apparatus may be a monochrome / color copying machine, a printer, a facsimile machine, or a multifunction machine (MFP) thereof. The hardware configuration of the image forming apparatus is not limited to the above.

  The processing in the above-described embodiment may be performed by software or may be performed using a hardware circuit.

  A program for executing the processing in the above-described embodiment can be provided, or the program can be recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, or a memory card and provided to the user. It may be. The program may be downloaded to the apparatus via a communication line such as the Internet. The processing described in the text in the above flowchart is executed by the CPU according to the program.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Image forming part 5 Image reading part 12a 1st CPU
12b Second CPU
14 memory controller PCI bridge 15 file memory 16a first work memory 16b second work memory 16c shared work memory 20a control program 21 job management unit 22 network management unit 23 analysis processing unit 24 drawing processing unit 25 compression control unit 30 display list 31 print Possible data 50 Control circuit 500 External device

Claims (17)

A drawing processing unit that performs print processing in units of bands based on print data to be processed to generate printable data, and performs a compression instruction to compress the printable data;
Prior to the drawing process, a determination unit that determines the presence or absence of an image in a band unit based on the print data;
A compression control unit that compresses the printable data in band units based on a compression instruction by the drawing processing unit;
The drawing processing unit
The compression instruction is not performed for the no-image band that is determined to have no image by the determination unit,
An image forming apparatus that performs the compression instruction in band units for printable data of bands other than the non-image band. Prior to the drawing process, the determination unit is configured to draw a first processing mode without rotation on the paper based on the print data, and to the paper by 90 degrees or 270 degrees from the first processing mode. The print data for image formation for one page is compressed on the basis of the number of non-image bands determined to have no image and the bandwidth for each of the second processing modes that are rotated and drawn. Calculate the processing time required to
The image forming apparatus according to claim 1, wherein the drawing processing unit performs the drawing processing in a processing mode in which the processing time calculated by the determination unit is shorter. A drawing processing unit that performs print processing in units of bands based on print data to be processed to generate printable data, and performs a compression instruction to compress the printable data;
Prior to the drawing process, a determination unit that determines the presence or absence of an image in a band unit based on the print data;
A compression control unit that compresses the printable data in band units based on a compression instruction by the drawing processing unit;
Prior to the drawing process, the determination unit is configured to draw a first processing mode without rotation on the paper based on the print data, and to the paper by 90 degrees or 270 degrees from the first processing mode. The print data for image formation for one page is compressed on the basis of the number of non-image bands determined to have no image and the bandwidth for each of the second processing modes that are rotated and drawn. Calculate the processing time required to
The image forming apparatus, wherein the drawing processing unit performs the drawing process in a processing mode with a shorter processing time calculated by the determination unit. The determination unit collectively determines the no-image band for the page before performing the compression instruction for print data for image formation for one page for the first time,
4. The image forming apparatus according to claim 1, wherein the compression control unit acquires information on the imageless bands determined in a batch before the print data is compressed for the first time. 5. An analysis processing unit that analyzes the print data and generates a display list;
The image forming apparatus according to claim 1, wherein the drawing processing unit generates the printable data based on a display list generated by the analysis processing unit. The image forming apparatus is configured using a control circuit having a core of at least two central processing units,
The drawing processing unit functions based on an operation of a first core of the at least two cores,
The image forming apparatus according to claim 1, wherein the compression control unit functions based on an operation of a second core different from the first core among the at least two cores.   The image forming apparatus according to claim 1, wherein the drawing processing unit reduces the number of times of the compression instruction from the drawing processing unit to the compression control unit in accordance with a determination result by the determination unit. An image forming system having an image forming apparatus and an external device that transmits print data to be processed to the image forming apparatus,
The external device includes a determination unit that determines whether or not there is an image in a band unit of print data for image formation for one page before transmitting the print data to the image forming apparatus,
The image forming apparatus includes:
A drawing processing unit that performs print processing on a band basis based on print data transmitted from the external device to generate printable data, and performs a compression instruction for compressing the printable data;
A compression control unit that compresses the printable data in band units based on a compression instruction by the drawing processing unit;
The drawing processing unit
The compression instruction is not performed for the no-image band that is determined to have no image by the determination unit,
An image forming system that issues the compression instruction in band units for printable data of bands other than the non-image band. The determination unit collectively determines the non-image band for print data for image formation for one page,
The image forming system according to claim 8, wherein the compression control unit acquires information on the imageless bands determined in a batch before the print data is first compressed. The image forming apparatus further includes an analysis processing unit that analyzes the print data and generates a display list,
The image forming system according to claim 8, wherein the drawing processing unit generates the printable data based on a display list generated by the analysis processing unit. The image forming apparatus is configured using a control circuit having a core of at least two central processing units,
The drawing processing unit functions based on an operation of a first core of the at least two cores,
The image forming system according to claim 8, wherein the compression control unit functions based on an operation of a second core different from the first core among the at least two cores.   The image forming system according to claim 8, wherein the number of compression instructions from the drawing processing unit to the compression control unit is reduced according to a determination result by the determination unit. A drawing process step of performing print processing for each band based on print data to be processed to generate printable data, and performing a compression instruction for compressing the printable data;
Prior to the drawing process, a determination step of determining the presence or absence of an image in band units based on the print data;
A compression control step for compressing the printable data in band units based on a compression instruction in the drawing processing step;
The drawing processing step includes
The compression instruction is not performed for the no-image band determined to have no image in the determination step,
A method for controlling an image forming apparatus, wherein the compression instruction is given in band units for printable data of bands other than the non-image band. A drawing process step of performing print processing for each band based on print data to be processed to generate printable data, and performing a compression instruction for compressing the printable data;
Prior to the drawing process, a determination step of determining the presence or absence of an image in band units based on the print data;
A compression control step for compressing the printable data in band units based on a compression instruction in the drawing processing step;
Prior to the drawing process, the determining step includes: a first processing mode drawn without rotation on the paper based on the print data; and a 90 degree or 270 degree from the first processing mode on the paper. The print data for image formation for one page is compressed on the basis of the number of non-image bands determined to have no image and the bandwidth for each of the second processing modes that are rotated and drawn. Calculate the processing time required to
The image forming apparatus control method, wherein the drawing processing step performs the drawing processing in a processing mode in which the processing time calculated in the determination step is shorter. A drawing process step of performing print processing for each band based on print data to be processed to generate printable data, and performing a compression instruction for compressing the printable data;
Prior to the drawing process, a determination step of determining the presence or absence of an image in band units based on the print data;
Based on a compression instruction by the drawing processing step, the computer executes a compression control step for compressing the printable data in band units,
The drawing processing step includes
The compression instruction is not performed for the no-image band determined to have no image in the determination step,
A control program for an image forming apparatus that issues the compression instruction in band units for printable data of bands other than the non-image band. A drawing process step of performing print processing for each band based on print data to be processed to generate printable data, and performing a compression instruction for compressing the printable data;
Prior to the drawing process, a determination step of determining the presence or absence of an image in band units based on the print data;
Based on a compression instruction by the drawing processing step, the computer executes a compression control step for compressing the printable data in band units,
Prior to the drawing process, the determining step includes: a first processing mode drawn without rotation on the paper based on the print data; and a 90 degree or 270 degree from the first processing mode on the paper. The print data for image formation for one page is compressed on the basis of the number of non-image bands determined to have no image and the bandwidth for each of the second processing modes that are rotated and drawn. Calculate the processing time required to
A control program for an image forming apparatus, wherein the drawing processing step performs the drawing processing in a processing mode in which the processing time calculated in the determination step is shorter. A control program for an image forming apparatus used in an image forming system having an image forming apparatus and an external device that transmits print data to be processed to the image forming apparatus,
The external device includes a determination unit that determines whether or not there is an image in a band unit of print data for image formation for one page before transmitting the print data to the image forming apparatus,
The control program for the image forming apparatus is:
A drawing process step of generating printable data by performing drawing processing in units of bands based on print data transmitted from the external device, and performing a compression instruction for compressing the printable data;
Based on a compression instruction by the drawing processing step, the computer executes a compression control step for compressing the printable data in band units,
The drawing processing step includes
The compression instruction is not performed for the no-image band determined to have no image in the determination step,
A control program for an image forming apparatus that issues the compression instruction in band units for printable data of bands other than the non-image band.

Images