JP2006035699A - Image processor, image forming device, image processing method, and image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor capable of executing the output of data corresponding to high-speed image formation in a state that a storage capacity of a page memory is set to the required minimum. <P>SOLUTION: A system controller controls an image controller so that processing for writing the data, which are included in an image to be subjected to the image formation next time, to the page memory during a period when data included in an image for one page are read out from the page memory. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus provided in an image forming apparatus using, for example, an electrophotographic method, an image forming apparatus including the image processing apparatus, and an image processing program.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copiers, printers, and MFPs (Multi Function Printers) that have both of these functions have been widely used. In such an image forming apparatus, for example, print job data received from a PC as a host or image data read by a scanner unit is temporarily stored in a hard disk device in the image forming apparatus. Thereafter, the data is transferred to the page memory in the image forming apparatus, and the data is transmitted from the page memory to the print engine at an appropriate timing.

  As described above, the page memory needs to read data at an appropriate timing according to the image forming speed in the print engine. Also, the data used for image formation is relatively large. That is, the page memory is required to have real-time and high-speed writing and reading. An example of a memory that satisfies such a requirement is a DRAM (Dynamic Random Access Memory).

In Patent Document 1 to be described later, in an image forming apparatus that performs color printing with four colors of Y, M, C, and K, each color buffer (page memory) is formed on a photosensitive drum corresponding to each color. An image forming apparatus having a memory capacity for storing image data of a timing difference at which an image is transferred to a transfer body is disclosed. More specifically, in this conventional image forming apparatus, in order to ensure that all four colors of image data YMCK are present in the page buffer at the timing when the sheet is fed out, the gap between the photosensitive drums is provided in the page buffer corresponding to each color. A memory area corresponding to is added. That is, the memory capacity of each color buffer is different.
JP 2002-113905 A (published April 16, 2002)

  In the above-described conventional image forming apparatus, when image formation of a plurality of pieces of image data is performed, a plurality of pieces of image data are stored in each color buffer. This is intended to ensure a desired output speed during continuous printing. However, as described above, since memory that requires real-time and high-speed writing and reading is relatively expensive, when using a buffer having a capacity capable of storing a plurality of pieces of image data. There is a problem that the cost of the apparatus becomes high.

  In addition, when performing duplex printing, the required buffer capacity is further increased. For example, FIG. 10 in Patent Document 1 shows an example in which 8 to 10 pages of image data are stored in each color buffer when performing duplex printing.

  The present invention has been made in view of the above problems, and an object of the present invention is to enable data output corresponding to high-speed image formation in a state where the storage capacity of the page memory is minimized. An object is to provide an image processing apparatus, an image forming apparatus, an image processing method, and an image processing program.

  In order to solve the above-described problems, an image processing apparatus according to the present invention includes a data storage unit that stores the data, and the data storage unit in an image processing apparatus that outputs data to be image-formed to a printer engine. A storage unit control unit that performs a process of writing data to be image-formed, and a process of reading out data to be image-formed from the data storage unit and outputting the data to the printer engine, and the storage unit control unit Processing control means for controlling the processing according to the above, and during the period when the data included in one unit image is read from the data storage unit, the data storage unit stores the data included in the image to be imaged next The process control unit controls the storage unit control unit so that a process of writing to the storage unit is performed.

  The image processing method according to the present invention is an image processing method in an image processing apparatus that outputs data to be image-formed to a printer engine. And a process of reading out data to be formed from the data storage unit and outputting the data to the printer engine, and data included in one unit image is read from the data storage unit. In a certain period, data included in an image to be imaged next is written into the data storage unit.

  In the configuration and method described above, data to be imaged is temporarily stored in the data storage unit, and then the data stored in the data storage unit is output to the printer engine. Thereby, it is possible to output data appropriately following the image forming speed in the printer engine.

  In the configuration and method described above, the process of writing the data included in the next image to be formed into the data storage unit during the period in which the data included in one unit image is read from the data storage unit. Is to be done. Here, one unit image corresponds to, for example, an image formed on one page of a print medium. According to such processing, it is possible to complete the writing processing of data included in the next image immediately after the reading of data included in one unit of image is completed. Therefore, even when the storage capacity of the data storage unit is about the amount of data for one unit of image, it is possible to output data that appropriately follows the image forming speed in the printer engine. In other words, it is possible to output data corresponding to high-speed image formation in a state where the storage capacity of the data storage unit is minimized.

  Further, in the image processing apparatus according to the present invention, in the above configuration, the first direction as the direction in which the data included in one unit image to be formed is sequentially written to or read from the data storage unit is the first direction. And a second direction opposite to the first direction, a reading direction in which data included in one unit image is read from the data storage unit, and a period during which the data is read In addition, the processing control unit may control the storage unit control unit so that the data included in the image to be imaged next matches the writing direction in which the data is written to the data storage unit. Good.

  According to the above configuration, when reading and writing are simultaneously performed on the data storage unit, the reading direction and the writing direction coincide with each other. Therefore, data can be read and written at the same time by writing to the memory area where the data has been read in the data storage unit.

  In addition, in the image processing apparatus according to the present invention, in the above configuration, the data storage unit reads data sequentially from the data that has been written during the period in which the data included in one unit image is written. As described above, the processing control unit may control the storage unit control unit.

  According to the above configuration, during the period in which the data included in one unit image is written in the data storage unit, the reading is sequentially performed from the data that has been written. According to such processing, the data read timing can be advanced, so that the processing speed can be increased.

    Further, in the image processing apparatus according to the present invention, in the above configuration, the first direction as the direction in which the data included in one unit image to be formed is sequentially written to or read from the data storage unit is the first direction. And a second direction opposite to the first direction, and a writing direction in which data included in one unit image is written from the data storage unit, and writing in the writing period The processing control unit may control the storage unit control unit so that the reading direction in which the data that has been completed is read matches.

  According to the above configuration, when writing and reading are simultaneously performed on the data storage unit, the writing direction matches the reading direction. Therefore, it is possible to read from the data for which writing has been completed in the data storage unit.

  In the image processing apparatus according to the present invention, in the above configuration, the data to be formed is data in which data of a plurality of color components is included in data corresponding to one unit of image. The storage control unit may be configured to control the processing control unit so that the data of each color component is read out separately and output to the printer engine.

  Generally, a printer engine often performs image formation of each color component at different timings when printing a plurality of colors. This is because the printer engine has a configuration in which the image forming units for the respective color components are arranged at predetermined intervals with respect to the conveyance path of the print medium.

  Here, according to the above configuration, the storage unit control means reads out the data of each color component separately and outputs it to the printer engine. Therefore, the data reception of each color component is optimal in the printer engine. Thus, it is possible to output data of each color component so that the timing is correct.

  In the image processing apparatus according to the present invention, in the above configuration, the data to be imaged is data in which the data of each color component is independent of each other for one unit of image, and the data storage unit Includes a plurality of color component data storage units corresponding to the respective color components, and the storage unit control means writes the data of each color component in the corresponding color component data storage unit and the data of each color component to each color component. The processing control means may be configured to control such that the data is read separately from the data storage unit and output to the printer engine.

  According to the above configuration, since a plurality of color component data storage units corresponding to each color component are provided, writing and reading of data of each color component are performed in independent color component data storage units. . Accordingly, it is possible to reduce the amount of data written and read in one color component data storage unit as compared with the case where the data of each color component is written and read out in one data storage unit. Data writing and reading can also be simplified. Therefore, the control of the storage unit control means can be simplified.

  In the image processing apparatus according to the present invention, in the above configuration, the processing control unit sends data included in one unit image to be imaged to the data storage unit. The first step of writing in the first direction and reading the data in the first direction, and the data included in one unit image to be imaged next to the data storage unit In the second direction and reading the data in the second direction, and further, data included in one unit of image to be imaged in the second direction with respect to the data storage unit in the second direction. Writing, reading the data in the second direction, and writing data included in one unit of image to be imaged in the second direction to the data storage unit in the second direction; data It may be controlled so as to perform repeatedly a fourth step of reading in the first direction.

  In the above configuration, data is output in four steps as one cycle. The reading direction in each step coincides with the writing direction in the subsequent step. Therefore, data corresponding to high-speed image formation can be output with almost no time lag between reading and writing between each step.

  Here, in general, when duplex printing is performed on a print medium in a printer engine, the end of the print medium that is forward with respect to the transport direction during front-side printing is backward in the transport direction during back-side printing. Will be located. That is, the direction of image formation is reversed between front side printing and back side printing.

  In contrast, according to the above configuration, first, the reading direction in the first step is the first direction, and the reading direction in the second step is the second direction. It is possible to align the vertical direction of the image printed on the front side of the medium and the image printed on the back side. Similarly, since the reading direction in the third step is the second direction and the reading direction in the fourth step is the first direction, the image printed on the front side of the print medium and the back side It is possible to align the vertical direction with the image to be printed.

  That is, according to the above configuration, it is possible to output data corresponding to high-speed image formation to a printer engine that performs duplex printing.

  The image processing apparatus according to the present invention may be configured such that, in the above configuration, the processing control unit controls the storage unit control unit to repeat each of the steps a predetermined number of times. Good.

  When the printer engine performs a plurality of duplex printings, in order to improve the printing processing speed, the printing on the first sheet is completed and the second printing medium is in the process of reversing and conveying the first printing medium. There are cases where the first or more sheets are printed on the surface. According to the above configuration, it is possible to perform data output corresponding to the case where a plurality of prints are performed in each of the printing on the front surface and the back surface of the print medium.

  In order to solve the above-described problems, an image forming apparatus according to the present invention includes the image processing apparatus according to the present invention and a printer engine.

  According to the above configuration, since the image processing apparatus can output data corresponding to high-speed image formation in a state where the storage capacity of the data storage unit is minimized, it is inexpensive. In addition, it is possible to provide an image forming apparatus capable of performing high-speed image formation.

As described above, the image processing apparatus and the image processing method according to the present invention include data included in an image to be imaged next in a period in which data included in one unit image is read from the data storage unit. Is written into the data storage unit. As a result, it is possible to output data corresponding to high-speed image formation in a state where the storage capacity of the data storage unit is minimized. 1
The image forming apparatus according to the present invention includes the image processing apparatus according to the present invention and a printer engine as described above. Therefore, there is an effect that it is possible to provide an image forming apparatus that is inexpensive and can perform high-speed image formation.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 9 as follows.

(Print system configuration)
FIG. 7 is a block diagram illustrating a schematic configuration of the print system according to the present embodiment. As shown in the figure, the print system includes an MFP (image forming apparatus) 1 and a host 2.

  The MFP 1 includes a scanner unit 4, a printer engine 5, and a printer controller (image processing device) 3, and prints a print job transmitted from the host 2, an image read by the scanner unit 4, and the like. An MFP that performs print processing. The host 2 is a terminal device configured by, for example, a PC and the like, which generates a print job and issues a print instruction to the MFP 1. The host 2 and the MFP 1 are communicatively connected via a communication path, and a print job sent from the host 2 to the MFP 1 is transmitted / received via this communication path. The communication path is not particularly limited, and examples thereof include a wired communication path such as a USB (Universal Serial Bus) cable and a LAN cable, and a wireless communication path such as a wireless LAN.

  In the MFP 1, the scanner unit 4 generates image data by optically reading a document image. The printer engine 5 performs print processing on a print medium based on image data to be printed.

  The printer controller 3 controls various processes in the MFP 1, and includes a host I / F 6, HDD 7, I / O controller 8, system controller (processing control unit) 9, image processing LSI 10, image controller (storage unit control unit). 11 and a RAM (data storage unit) 12.

  The host I / F 6 is a block that functions as an interface when communicating with the host 2. When the host 2 and the MFP 1 are connected by USB, the host I / F 6 corresponds to a USB interface, and when the host 2 and the MFP 1 are connected by LAN, the host I / F 6 is a LAN interface. It corresponds to.

  The HDD 7 is a hard disk device that records print job data sent from the host 2, image data read by the scanner unit 4, and various data and programs used in other printer controllers. In this embodiment, a hard disk device is used as the nonvolatile recording device. However, the present invention is not limited to this, and the nonvolatile recording device may be realized by a flash memory, for example.

  The I / O controller 8 controls input / output of print job data received by the host I / F 6 and data to be written to and read from the HDD 7.

  The system controller 9 controls operations of various processing blocks in the printer controller 3. In the present embodiment, the system controller 9 implements control by reading various control programs into the system memory (RAM) 9a and executing them by the CPU 9b. The control processing in the system controller 9 is not limited to such software processing, and may be realized by hardware logic such as LSI.

  The image processing LSI 10 is an LSI that performs various types of image processing on image data to be printed and then performs processing for transmitting data to the printer engine 5. Examples of the image processing performed here include processing for converting RGB format data into CMYK format data, tone conversion processing, dither processing, and γ processing. If a sufficient processing speed can be obtained, the image processing performed by the image processing LSI 10 may be realized by software processing.

  The RAM 12 is temporary storage means for storing image data to be printed by the printer engine 5, and includes a page memory 13 as a memory area for storing image data. The page memory 13 has a capacity capable of storing at least one page of image data including data of each color component.

  The image controller 11 performs processing for transferring image data read by the scanner unit 4, processing for transferring data to be transmitted to the printer engine 5, and the like. Since the image controller 11 basically needs to perform high-speed data processing, it is configured by, for example, an LSI. If a sufficient processing speed can be obtained, the processing performed by the image controller 11 may be realized by software processing.

  In the above configuration, the page memory 13 in the RAM 12 stores image data including data of each color component. However, when the image data of each color component is handled in an independent state. Alternatively, a page memory for each color component corresponding to the image data of each color component may be provided. In the example shown in FIG. 8, a configuration example of the RAM 12 in the case where there is image data of K (Black) component, C (Cyan) component, M (Magenta) component, and Y (Yellow) component as image data of each color component. Show. In this case, the RAM 12 is provided with a K component page memory 13K, a C component page memory 13C, an M component page memory 13M, and a Y component page memory 13Y.

  In the printer system according to the present embodiment, an MFP is used as an apparatus for performing print processing. However, the present invention is not limited to this, and is a printer that performs only print processing based on a print job from the host 2. Alternatively, it may be a copying machine having only a copying function. In the case of a printer, it is not necessary to provide the scanner unit 4 shown in FIGS. In the case of a copying machine, the host I / F 6 shown in FIGS. 7 and 8 need not be provided.

  Note that the system controller 9 can be realized by executing a program developed by a calculation unit such as the CPU 9b in a storage unit such as the system memory 9a as described above. Therefore, various functions and various processes of the system controller 9 can be realized simply by a computer having these means reading the recording medium storing the program and executing the program. In addition, by recording the program on a removable recording medium, the various functions and various processes described above can be realized on an arbitrary computer.

  Although not shown, the recording medium may be a program medium that is provided with a program reading device as an external storage device and can be read by inserting the recording medium therein.

  In any case, the stored program is preferably configured to be accessed and executed by the microprocessor. Furthermore, it is preferable that the program is read out, and the read program is downloaded to the program storage area of the microcomputer and the program is executed. It is assumed that the download program is stored in the main device in advance.

  In addition, if the system configuration is capable of connecting to a communication network including the Internet, the recording medium is preferably a recording medium that fluidly carries the program so as to download the program from the communication network.

(Example of printer engine configuration)
FIG. 9 is a cross-sectional view showing a schematic configuration of the printer engine 5. The printer engine 5 includes an image forming unit 210, a paper feed unit 211, and a paper discharge unit 229.

  The paper feed unit 211 includes a paper tray 233, a paper feed roller 234, a registration roller 212, and the like, and separates the print media P stacked and stored in the paper tray 233 one by one to the image forming unit 210. To supply. The print media P separated and supplied one by one are conveyed to the image forming unit 210 with timing controlled by a pair of registration rollers 212 disposed between the paper tray 233 and the image forming unit 210. Yes. In the so-called double-sided image forming mode in which images are formed on both sides of the print medium P, the print medium P having an image formed on one side is synchronized with the timing at which the image forming unit 210 forms an image on the other side. The image forming unit 210 is conveyed again.

  In the printer engine 5 in the present embodiment, cut sheet-like paper is used as the print medium P. When the print medium P is sent out from the paper tray 233 and supplied into a guide in the paper feed conveyance path of the paper feed unit 211, the leading end of the print medium P is detected by a sensor (not shown). . The print medium P is temporarily stopped by the pair of registration rollers 212 based on the detection signal output from the sensor, and is conveyed to the image forming unit 210 according to the image formation timing. .

  The image forming unit 210 forms an image on the print medium P based on the image data sent from the image controller 11. The image forming unit 210 includes a transfer conveyance belt mechanism 213, a fixing device 217, an image forming station 228, and a laser writing unit 227.

  The transfer conveyance belt mechanism 213 is a mechanism for conveying the print medium P supplied through the paper supply unit 211 to the image forming station 228 in accordance with the image formation timing.

  The image forming station 228 reproduces a toner image corresponding to the image information of the document on the print medium P. The image forming station 228 includes a K component station 228K, a C component station 228C, an M component station 228M, and a Y component station 228Y. The color component stations 228K, 228C, 228M, and 228Y are arranged in order from the upstream side of the sheet conveyance path.

  The color component stations 228K, 228C, 228M, and 228Y have substantially the same configuration, and each include a photosensitive drum, a charger, a developing device, a transfer roller, and a cleaning device.

  The laser writing unit 227 writes an electrostatic latent image on the photosensitive drum based on the image information. The laser writing unit 227 includes a K component laser writing unit 227K, a C component laser writing unit 227C, an M component laser writing unit 227M, and a Y component laser writing unit 227Y. The laser writing units 227K, 227C, 227M, and 227Y are provided above the photosensitive drums.

  The print medium P is sequentially conveyed to the color component stations 228K, 228C, 228M, and 228Y to form toner images of the respective colors. When the transfer of the image of each color component is completed, the print medium P is conveyed to the fixing device 217, and the toner image is fixed.

  The paper discharge unit 229 discharges the print medium P on which image formation has been completed to the outside. The discharge unit 229 includes a conveyance direction switching gate 218, discharge rollers 219, and a discharge tray 220. The print medium P transported from the fixing device 217 is transported by a discharge roller 219 through a transport direction switching gate 218 and discharged onto a paper discharge tray 220 from a paper discharge port (not shown).

  The transport direction switching gate 218 switches the transport path of the print medium P after the toner image is fixed, and reroutes the print medium P toward the image forming unit 210 and the path for discharging the print medium P to the paper discharge tray 220. The supply path is selectively switched. In the double-sided image forming mode, after an image is formed on one side of the print medium P, the print medium P is switched by the transport direction switching gate 218 so that the transport direction is switched again toward the image forming unit 210, and the switchback transport is performed. After being turned upside down via the path 221, it is supplied again to the image forming unit 210. In the single-sided image formation mode, after an image is formed on one side of the print medium P, it passes through the transport direction switching gate 218 and is discharged onto the discharge tray 220 by the discharge roller 219.

  In this embodiment, the color component stations 228K, 228C, 228M, and 228Y are arranged in this order from the upstream side in the transport direction of the print medium P. However, the present invention is not limited to this. They may be arranged in any order, for example, the order may be Y, M, C, K. Further, in the following print processing example, the description is based on the assumption that the order of each color is K, C, M, and Y. However, it is possible to appropriately change according to the arrangement order of each color component station. is there.

(Print processing example 1: Same plane method, even paper)
First, a process in a case where data of each color component is included in one image data and printing on the front surface and the back surface is performed at equal intervals will be described with reference to FIG. Here, the printing process is performed in the following four steps. In the first step, writing to the page memory 13 is performed in the forward direction, reading from the page memory 13 is performed in the forward direction, and printing is performed on the front surface. In the second step, writing to the page memory 13 is performed in the forward direction, reading from the page memory 13 is performed in the reverse direction, and printing is performed on the back surface. In the third step, writing to the page memory 13 is performed in the reverse direction, reading from the page memory 13 is performed in the reverse direction, and printing is performed on the front surface. In the fourth step, writing to the page memory 13 is performed in the reverse direction, reading from the page memory 13 is performed in the forward direction, and printing is performed on the back surface.

  Note that the forward direction indicates a direction in which writing or reading is performed in the order of the main scanning direction and the sub-scanning direction from the upper left data of the image corresponding to the image data, and the reverse direction is the image direction. The direction in which writing or reading is performed in the order of the reverse of the main scanning direction and the sub-scanning direction from the lower right data of the image corresponding to the data is shown.

  Examples of the image data written to the page memory 13 include image data sent as data to be printed from the host 2 and image data read by the scanner unit 4. Such image data is temporarily stored in the HDD 7, then sent from the HDD 7 to the image processing LSI 10 via the I / O controller 8 and the image controller 11, and then written in the page memory 13. Note that image processing by the image processing LSI 10 may be performed when the image data is output from the page memory 13 to the printer engine 5.

  In FIG. 1, an area indicated by “page memory write” indicates in which direction the image data is written in the page memory 13, and the vertical direction indicates the arrangement of the pixel data of the image data. . Further, “VSYNC_K”, “VSYNC_C”, “VSYNC_M”, and “VSYNC_Y” indicate the waveform of the SYNC signal that indicates the timing of reading the image data of the K component, the C component, the M component, and the Y component, respectively. Yes. The areas indicated by “page memory K read”, “page memory C read”, “page memory M read”, and “page memory Y read” are the K component, C component, M component, and Y component, respectively. The direction in which the image data is read is shown, and the vertical direction shows the arrangement of the pixel data of the image data. An area indicated by “change in page memory data” indicates a change in the amount of data stored in the page memory 13.

  Details of each step will be described below.

(First step)
First, under the control of the image controller 11, writing of image data to the page memory 13 is started at time T1. In this first step, the image data is written to the page memory 13 in the forward direction, so that the image data is written to the page memory 13 in order from the upper left data. Then, the writing of the image data to all the page memories 13 is completed at time T2. At the timing of this time T2, all data of the image data to be printed is stored in the page memory 13.

  At time T2, the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the K component image data from the page memory 13 in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from High to Low (until time T6), the image controller 11 stores the image data of the K component from the page memory 13. Read. As a result, all of the K component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the K component station 228K in the printer engine 5 to print the K component. The printing of the K component is performed so that the leading side is the upper side of the image of the image data in the conveyance direction of the print medium during printing. An image printed in such a state is referred to as a 0-degree rotated image.

  As described above, since the reading direction of the image data from the page memory 13 and the printing direction of the image data in the printer engine coincide with each other, printing can be performed while reading.

  When the image controller 11 reads the K component image data from the page memory 13, it immediately erases the corresponding data from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the K component image data is read, in other words, the free capacity of the page memory 13 increases. In the above description, the corresponding data is sequentially erased from the page memory 13 immediately after being read. However, it is not always necessary to completely erase the data, and the data may be erased from the management table of the page memory 13. Thereafter, the same erasing process is performed for the other color components.

  When the time T2 has passed and the time T3 has passed, the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the C component image data from the page memory 13 in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from High to Low (until time T7), the image controller 11 stores the C component image data from the page memory 13. Read. As a result, all of the C component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the C component station 228C in the printer engine 5 to print the C component. The printing of the C component is performed as a 0-degree rotated image, similarly to the printing of the K component.

  When the image controller 11 reads the C component image data from the page memory 13, the image controller 11 erases the corresponding data in order from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the C component image data is read, in other words, the free space in the page memory 13 increases.

  When the time T3 passes and the time T4 is reached, the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from Low to High. Along with this, the image controller 11 starts reading the M component image data from the page memory 13 in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from High to Low (until time T 9), the image controller 11 stores the M component image data from the page memory 13. Read. As a result, all of the M component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the M component station 228M in the printer engine 5 to print the M component. The printing of the M component is performed as a 0-degree rotated image, similarly to the printing of the K component and the C component.

  When the image controller 11 reads the M component image data from the page memory 13, the image controller 11 erases the corresponding data in order from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the M component image data is read, in other words, the free space in the page memory 13 increases.

  When time T4 has passed and time T5 has elapsed, the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the Y component image data from the page memory 13 in the forward direction. After that, until the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from High to Low (until time T10), the image controller 11 stores the Y component image data from the page memory 13. Read. As a result, all of the Y component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the Y component station 228Y in the printer engine 5 to print the Y component. The printing of the Y component is performed as a 0-degree rotated image, similarly to the printing of the K component, the C component, and the M component.

  When the image controller 11 reads the Y component image data from the page memory 13, the image controller 11 sequentially erases the corresponding data from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the Y component image data is read, in other words, the free space in the page memory 13 increases.

  Here, the timing of VSYNC_K, VSYNC_C, VSYNC_M, and VSYNC_Y, that is, the read start timing of the image data of each color component will be described. As described above, in the printer engine 5, the stations corresponding to the respective color components are arranged at a predetermined interval in the print medium conveyance direction. That is, in order to print the image data of each color component at the same position on the print medium, it is necessary to set the printing timing of the station corresponding to each color component according to the conveyance speed of the print medium and the position of each station. .

  The printer engine 5 of this embodiment has a configuration in which a K component station 228K, a C component station 228C, an M component station 228M, and a Y component station 228Y are arranged in this order from the upstream side of the print medium conveyance. Therefore, VSYNC_K, VSYNC_C, VSYNC_M, and VSYNC_Y are set so that the image data of each color component is printed at the same position on the print medium. For example, the time interval between the time T2 at which VSYNC_K changes from Low to High and the time T3 at which VSYNC_C changes from Low to High is such that the print medium moves from the printing position of the K component station 228K to the C component station 228C. This corresponds to the time required to move to the printing position.

  As described above, the K component image, the C component image, the M component image, and the Y component image are printed as a 0-degree rotated image on the print medium, thereby performing color printing on the surface of the first print medium. Is done.

(Second step)
The image controller 11 performs control to start writing image data to be printed on the back surface of the first print medium in the forward direction at time T8. Here, the time T8 is a time between the time T7 and the time T9 described above, and is the timing at which the image data in the first step still remains in the page memory 13. That is, during the time between time T8 and time T10, the page memory 13 is simultaneously reading and writing data. By performing such processing, the processing speed can be improved as compared with, for example, the case where writing is performed after data reading is completely completed.

  Here, the reason why there is no problem even if data reading and writing are simultaneously performed in the page memory 13 will be described. In the first step, as described above, the image data of each color component is read from the page memory 13 in the forward direction. In the second step, image data is written to the page memory 13 in the forward direction. Therefore, in the page memory 13, data reading and writing can be simultaneously performed by performing writing in the second step with respect to the memory area in which reading in the first step is completed. is doing.

  Thereafter, at time T11 after time T10 when reading of image data is completed in the first step, writing of all image data to be printed on the back surface of the first print medium is completed. At the timing of this time T11, the page memory 13 stores all the data of the image data to be printed.

  At time T11, the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the K component image data from the page memory 13 in the reverse direction. After that, until the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from High to Low (until time T15), the image controller 11 stores the K component image data from the page memory 13. Read. As a result, all of the K component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the K component station 228K in the printer engine 5 to print the K component. The printing of the K component is performed so that the leading side is the lower side of the image of the image data in the printing medium conveyance direction at the time of printing. An image printed in such a state is referred to as a 180-degree rotated image.

  Here, after the surface of the print medium is printed, the print medium is conveyed to the image forming unit 210 with the front and back being reversed by the switchback mechanism described above. In this case, the up-down direction of the print medium at the time of printing on the back surface is also reversed. That is, the end portion of the print medium that is forward with respect to the transport direction during front surface printing is positioned behind the transport direction during back surface printing. Therefore, at the time of back side printing, the 180 ° rotated image is printed, so that the vertical direction of the image printed on the front side of the print medium and the image printed on the back side is aligned.

  When the image controller 11 reads the K component image data from the page memory 13, it immediately erases the corresponding data from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the K component image data is read, in other words, the free capacity of the page memory 13 increases.

  When the time T11 passes and the time T12 is reached, the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the C component image data from the page memory 13 in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from High to Low (until time T16), the image controller 11 stores the C component image data from the page memory 13. Read. As a result, all of the C component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the C component station 228C in the printer engine 5 to print the C component. The C component printing is performed as a 180-degree rotated image in the same manner as the K component printing.

  When the image controller 11 reads the C component image data from the page memory 13, the image controller 11 erases the corresponding data in order from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the C component image data is read, in other words, the free space in the page memory 13 increases.

  When the time T12 passes and the time T13 is reached, the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from Low to High. Along with this, the image controller 11 starts reading the M component image data from the page memory 13 in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from High to Low (until time T18), the image controller 11 stores the M component image data from the page memory 13. Read. As a result, all of the M component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the M component station 228M in the printer engine 5 to print the M component. The printing of the M component is performed as a 180-degree rotated image similarly to the printing of the K component and the C component.

  When the image controller 11 reads the M component image data from the page memory 13, the image controller 11 erases the corresponding data in order from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the M component image data is read, in other words, the free space in the page memory 13 increases.

  When the time T13 has passed and the time T14 has passed, the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the Y component image data from the page memory 13 in the reverse direction. After that, until the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from High to Low (until time T19), the image controller 11 stores the Y component image data from the page memory 13. Read. As a result, all of the Y component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the Y component station 228Y in the printer engine 5 to print the Y component. The printing of the Y component is performed as a 180-degree rotated image, similarly to the printing of the K component, the C component, and the M component.

  When the image controller 11 reads the Y component image data from the page memory 13, the image controller 11 sequentially erases the corresponding data from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the Y component image data is read, in other words, the free space in the page memory 13 increases.

  As described above, the K component image, the C component image, the M component image, and the Y component image are printed as a 180-degree rotated image on the print medium, thereby performing color printing on the back surface of the first print medium. Is done.

(Third step)
The image controller 11 performs control to start writing image data to be printed on the surface of the second print medium in the reverse direction to the page memory 13 at time T17. Here, the time T17 is a time between the above-described time T16 and time T18, and is the timing at which the image data in the second step still remains in the page memory 13. In other words, during the time between time T17 and time T19, the page memory 13 is simultaneously reading and writing data. By performing such processing, as described above, for example, it is possible to improve the processing speed as compared with the case of performing writing after data reading is completely completed. As described in the second step, in the page memory 13, the data in the data is obtained by performing the writing in the third step with respect to the memory area in which the reading in the second step is completed. Reading and writing are performed at the same time.

  Thereafter, at time T20 after time T19 at which the reading of image data is completed in the second step, writing of all the image data to be printed on the surface of the second print medium is completed. At the timing of time T20, the page memory 13 stores all data of image data to be printed.

  At time T20, the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the K component image data from the page memory 13 in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from High to Low (until time T24), the image controller 11 stores the K component image data from the page memory 13. Read. As a result, all of the K component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the K component station 228K in the printer engine 5 to print the K component. The printing of the K component is performed so that the leading side is above the image of the image data in the print medium conveyance direction at the time of printing, that is, as a 0-degree rotated image.

  When the image controller 11 reads the K component image data from the page memory 13, it immediately erases the corresponding data from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the K component image data is read, in other words, the free capacity of the page memory 13 increases.

  When the time T20 passes and the time T21 is reached, the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the C component image data from the page memory 13 in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from High to Low (until time T 25), the image controller 11 stores the C component image data from the page memory 13. Read. As a result, all of the C component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the C component station 228C in the printer engine 5 to print the C component. The printing of the C component is performed as a 0-degree rotated image, similarly to the printing of the K component.

  When the image controller 11 reads the C component image data from the page memory 13, the image controller 11 erases the corresponding data in order from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the C component image data is read, in other words, the free space in the page memory 13 increases.

  When the time T21 passes and the time T22 is reached, the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from Low to High. Along with this, the image controller 11 starts reading the M component image data from the page memory 13 in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from High to Low (until time T27), the image controller 11 stores the M component image data from the page memory 13. Read. As a result, all of the M component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the M component station 228M in the printer engine 5 to print the M component. The printing of the M component is performed as a 0-degree rotated image, similarly to the printing of the K component and the C component.

  When the image controller 11 reads the M component image data from the page memory 13, the image controller 11 erases the corresponding data in order from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the M component image data is read, in other words, the free space in the page memory 13 increases.

  When time T22 passes and time T23 is reached, the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the Y component image data from the page memory 13 in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from High to Low (until time T28), the image controller 11 stores the Y component image data from the page memory 13. Read. As a result, all of the Y component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the Y component station 228Y in the printer engine 5 to print the Y component. The printing of the Y component is performed as a 0-degree rotated image, similarly to the printing of the K component, the C component, and the M component.

  When the image controller 11 reads the Y component image data from the page memory 13, the image controller 11 sequentially erases the corresponding data from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the Y component image data is read, in other words, the free space in the page memory 13 increases.

  As described above, the K component image, the C component image, the M component image, and the Y component image are printed as a 0-degree rotated image on the print medium, thereby performing color printing on the surface of the second print medium. Is done.

(Fourth step)
The image controller 11 performs control to start writing image data to be printed on the back surface of the second print medium in the reverse direction at time T26. Here, the time T26 is a time between the time T25 and the time T27 described above, and is the timing at which the image data in the third step still remains in the page memory 13. In other words, during the time between time T26 and time T29, the page memory 13 is simultaneously reading and writing data. By performing such processing, the processing speed can be improved as compared with, for example, the case where writing is performed after data reading is completely completed. As described in the second step, in the page memory 13, the data in the data is obtained by performing the writing in the fourth step with respect to the memory area in which the reading in the third step is completed. Reading and writing are performed at the same time.

  After that, at time T29 after time T28 when reading of image data is completed in the third step, writing of all the image data to be printed on the back surface of the second print medium is completed. At the timing of time T29, the page memory 13 stores all data of the image data to be printed.

  At time T29, the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the K component image data from the page memory 13 in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from High to Low (until time T33), the image controller 11 stores the K component image data from the page memory 13. Read. As a result, all of the K component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the K component station 228K in the printer engine 5 to print the K component. The printing of the K component is performed so that the top side is the lower side of the image of the image data in the conveyance direction of the print medium at the time of printing, that is, as a 180-degree rotated image. In this way, in printing on the second print medium, printing on the front side is performed with a 0-degree rotated image, and printing on the back side is performed with a 180-degree rotated image, whereby an image printed on the front side of the print medium, The vertical direction with the image printed on the back side is aligned.

  When the image controller 11 reads the K component image data from the page memory 13, it immediately erases the corresponding data from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the K component image data is read, in other words, the free capacity of the page memory 13 increases.

  When time T29 passes and time T30 is reached, the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the C component image data from the page memory 13 in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from High to Low (until time T34), the image controller 11 stores the C component image data from the page memory 13. Read. As a result, all of the C component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the C component station 228C in the printer engine 5 to print the C component. The C component printing is performed as a 180-degree rotated image in the same manner as the K component printing.

  When the image controller 11 reads the C component image data from the page memory 13, the image controller 11 erases the corresponding data in order from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the C component image data is read, in other words, the free space in the page memory 13 increases.

  When the time T30 passes and the time T31 is reached, the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from Low to High. Along with this, the image controller 11 starts reading the M component image data from the page memory 13 in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from High to Low (until time T36), the image controller 11 stores the M component image data from the page memory 13. Read. As a result, all of the M component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the M component station 228M in the printer engine 5 to print the M component. The printing of the M component is performed as a 180-degree rotated image similarly to the printing of the K component and the C component.

  When the image controller 11 reads the M component image data from the page memory 13, the image controller 11 erases the corresponding data in order from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the M component image data is read, in other words, the free space in the page memory 13 increases.

  When time T31 has passed and time T32 has elapsed, the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the Y component image data from the page memory 13 in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from High to Low (until time T37), the image controller 11 stores the Y component image data from the page memory 13. Read. As a result, all of the Y component image data is read out.

  The image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the Y component station 228Y in the printer engine 5 to print the Y component. The printing of the Y component is performed as a 180-degree rotated image, similarly to the printing of the K component, the C component, and the M component.

  When the image controller 11 reads the Y component image data from the page memory 13, the image controller 11 sequentially erases the corresponding data from the page memory 13 immediately after the reading. As a result, the area used for storage in the page memory 13 decreases as the Y component image data is read, in other words, the free space in the page memory 13 increases.

  As described above, the K component image, the C component image, the M component image, and the Y component image are printed as 180-degree rotated images on the print medium, whereby color printing is performed on the back surface of the second print medium. Is done.

  As described above, according to the print processing example 1, double-sided printing is performed at high speed while the storage capacity of the RAM 12 including the page memory 13 is set to a size that can store image data for one page. Data can be appropriately transmitted to the printer engine 5 to be performed without delay. In the print processing example 1, control corresponding to a configuration in which the print medium conveyance interval in the printer engine 5 is an equal interval is performed. Therefore, it is possible to make the conveyance control of the print medium in the printer engine 5 simpler.

(Print processing example 2: Same plane method, minimum paper interval)
Next, processing in a case where data of each color component is included in one image data and printing on the front surface and the back surface is not performed at equal intervals will be described with reference to FIG. Also in this process, similarly to the above-described print processing example 1, front and back double-sided printing is performed on two print media by the first to fourth steps.

  The purpose of printing processing example 1 is to simplify the control by printing the front and back surfaces at equal intervals. However, in this printing processing example 2, the front and back surfaces are printed as much as possible. The object is to increase the printing processing speed by controlling to perform it quickly.

  The print processing example 2 is different from the above-described print processing example 1 in the processing in the first step and the third step, and the other processing is the same. In the following, only processing different from print processing example 1 will be described.

(First step)
First, under the control of the image controller 11, writing of image data to the page memory 13 is started at time T1. In this first step, image data is written to the page memory 13 in the forward direction and read out in the forward direction. Therefore, the image data is written to the page memory 13 in order from the upper left data. At time T4, the writing of the image data to all the page memories 13 is completed.

  Here, in the first step, the image data of each color component is read from the page memory 13 in the forward direction. That is, the direction of writing to the page memory 13 and the direction of reading from the page memory 13 are the same. In other words, in the page memory 13, the order in which writing is performed and the order in which reading is performed are the same. Therefore, since it is possible to sequentially read from the memory area where the writing has been completed, it is possible to perform the reading before all the writing of the image data to the page memory 13 is completed.

  In this print processing example 2, by using this, at a time T2 that is a predetermined time after the time T1 at which image data writing starts and before the time T4 at which image data writing ends. The readout of the K component image data is started in the positive direction. Thereafter, reading of image data of the C component at time T3, the M component at time T5, and the Y component at time T6 is started.

(Third step)
After the second step, under the control of the image controller 11, writing of image data to the page memory 13 is started at time T11. In this third step, image data is written to the page memory 13 in the reverse direction and read out in the reverse direction, so that the image data is written to the page memory 13 in order from the upper left data. At time T14, the writing of the image data to all the page memories 13 is completed.

  Here, in the third step, reading of the image data of each color component from the page memory 13 is performed in the reverse direction. That is, the direction of writing to the page memory 13 and the direction of reading from the page memory 13 are the same. That is, as in the first step, since it is possible to sequentially read from the memory area where writing has been completed, reading is performed before all writing of image data to the page memory 13 is completed. It becomes possible.

  In this print processing example 2, by using this, at a time T12 that is a predetermined time after the time T11 when the writing of the image data is started and before the time T14 when the writing of the image data is finished. The readout of the K component image data is started in the reverse direction. Thereafter, reading of image data of the C component at time T13, the M component at time T15, and the Y component at time T16 is started.

  As described above, regarding the first step, in the printing process example 1, the reading of the K component image data is performed from the time when the writing of the image data is completed. The reading of the K component image data is started at a time T2 before the time T4 at which the writing of the image data ends. Regarding the third step, in the printing process example 1, the reading of the K component image data is performed from the time when the writing of the image data is completed, but in the printing process example 2, the image data is read out. At the time T12 before the time T14 when the writing ends, the reading of the K component image data is started. That is, according to the print processing example 2, in the first and third steps, it is possible to improve the print processing speed by the amount of time that the reading of the K component image data is started earlier.

(Print processing example 3: separate plane method, uniform paper interval)
Next, referring to FIG. 3 for processing when image data of each color component exists independently from each other for one image and printing of the front surface and the back surface is performed at equal intervals. While explaining. Here, the printing process is performed in the following four steps. In the first step, writing to the page memory corresponding to each color component is performed in the forward direction, reading from the page memory corresponding to each color component is performed in the forward direction, and printing is performed on the surface. . In the second step, writing to the page memory corresponding to each color component is performed in the forward direction, reading from the page memory corresponding to each color component is performed in the reverse direction, and printing is performed on the back surface. . In the third step, writing to the page memory corresponding to each color component is performed in the reverse direction, reading from the page memory corresponding to each color component is performed in the reverse direction, and printing is performed on the surface. . In the fourth step, writing to the page memory corresponding to each color component is performed in the reverse direction, reading from the page memory corresponding to each color component is performed in the forward direction, and printing is performed on the back surface. .

  Similarly to the print processing example 1 described above, the image data written to the page memory corresponding to each color component is read by the image data sent from the host 2 as data to be printed and the scanner unit 4. Image data. Such image data is temporarily stored in the HDD 7, then sent from the HDD 7 to the image processing LSI 10 via the I / O controller 8 and the image controller 11, and then written in the page memory 13. Note that image processing by the image processing LSI 10 may be performed when the image data is output from the page memory 13 to the printer engine 5.

  In FIG. 3, areas indicated by “page memory K write”, “page memory C write”, “page memory M write”, and “page memory Y write” are the K component, C component, M component, and Y, respectively. The component image data is written in the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y, and the vertical direction indicates the image data. The arrangement of each pixel data is shown. The areas indicated by “page memory K data change”, “page memory C data change”, “page memory M data change”, and “page memory Y data change” are the K component page memory 13K, C component page memory. 13C shows changes in the amount of data stored in the M component page memory 13M and the Y component page memory 13Y. Other areas are the same as those described with reference to FIG.

  Details of each step will be described below.

(First step)
First, under the control of the image controller 11, image data of each corresponding color component is written to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y at time T1. Be started. In this first step, the image data is written to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y in the forward direction. Are sequentially written into the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y. At time T2, writing of all the image data to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y is completed. At the timing of this time T2, the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y have all the data in the color components corresponding to the image data to be printed. Will be stored.

  At time T2, the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the K component image data from the K component page memory 13K in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from High to Low (until time T6), the image controller 11 stores the K component image from the K component page memory 13K. Read data. As a result, all of the K component image data is read out.

  The K component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the K component station 228K in the printer engine 5 to print the K component. Done. The printing of the K component is performed as a 0-degree rotated image.

  As described above, since the reading direction of the image data from the page memory 13 and the printing direction of the image data in the printer engine coincide with each other, printing can be performed while reading.

  When the image controller 11 reads the K component image data from the K component page memory 13K, the image controller 11 erases the corresponding data in order from the K component page memory 13K immediately after the reading. As a result, the area used for storage in the K component page memory 13K decreases as the K component image data is read, in other words, the free capacity of the K component page memory 13K increases. . In the above description, the corresponding data is erased in order from the K component page memory 13K immediately after reading. However, it is not always necessary to completely erase the data, and the data is erased from the management table of the K component page memory 13K. May be. Thereafter, the same erasing process is performed for the other color components.

  When the time T2 has passed and the time T3 has passed, the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the C component image data from the C component page memory 13C in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from High to Low (until time T7), the image controller 11 stores the C component image from the C component page memory 13C. Read data. As a result, all of the C component image data is read out.

  The C component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the C component station 228C in the printer engine 5 to print the C component. Done. The printing of the C component is performed as a 0-degree rotated image, similarly to the printing of the K component.

  When the image controller 11 reads the C component image data from the C component page memory 13C, the image controller 11 erases the corresponding data in order from the C component page memory 13C immediately after the reading. As a result, the area used for storage in the C component page memory 13C decreases as the C component image data is read, in other words, the free capacity of the C component page memory 13C increases. .

  When the time T3 passes and the time T4 is reached, the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the M component image data from the M component page memory 13M in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from High to Low (until time T9), the image controller 11 stores the M component image from the M component page memory 13M. Read data. As a result, all of the M component image data is read out.

  The M component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the M component station 228M in the printer engine 5 to print the M component. Done. The printing of the M component is performed as a 0-degree rotated image, similarly to the printing of the K component and the C component.

  When the image controller 11 reads M component image data from the M component page memory 13M, the image controller 11 erases the corresponding data in order from the M component page memory 13M immediately after the reading. As a result, the area used for storage in the M component page memory 13M decreases as the M component image data is read, in other words, the free capacity of the M component page memory 13M increases. .

  When time T4 has passed and time T5 has elapsed, the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the Y component image data from the Y component page memory 13Y in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from High to Low (until time T10), the image controller 11 stores the Y component image from the Y component page memory 13Y. Read data. As a result, all of the Y component image data is read out.

  The Y component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the Y component station 228Y in the printer engine 5 to print the Y component. Done. The printing of the Y component is performed as a 0-degree rotated image, similarly to the printing of the K component, the C component, and the M component.

  When the image controller 11 reads the Y component image data from the Y component page memory 13Y, the image controller 11 erases the corresponding data sequentially from the Y component page memory 13Y immediately after the reading. As a result, the area used for storage in the Y component page memory 13Y decreases as the Y component image data is read, in other words, the free capacity of the Y component page memory 13Y increases. .

  Note that the timings of VSYNC_K, VSYNC_C, VSYNC_M, and VSYNC_Y are set according to the print medium conveyance speed and the position of each station, as described above.

  As described above, the K component image, the C component image, the M component image, and the Y component image are printed as a 0-degree rotated image on the print medium, thereby performing color printing on the surface of the first print medium. Is done.

(Second step)
At time T8, the image controller 11 sends image data to be printed on the back surface of the first print medium to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y. To start writing in the forward direction. Here, the time T8 is a time between the time T7 and the time T9 described above, and the timing at which image data in the first step still remains in the M component page memory 13M and the Y component page memory 13Y. Become. That is, during the time between time T8 and time T10, data reading and writing are performed simultaneously in the M component page memory 13M and the Y component page memory 13Y. By performing such processing, the processing speed can be improved as compared with, for example, the case where writing is performed after data reading is completely completed. Here, the reason why there is no problem even if data reading and writing are simultaneously performed in the page memory 13 is the same as described above.

  Thereafter, at a time T11 after the time T10 when reading of the image data is completed in the first step, all the K component page memories 13K and C component pages of the image data to be printed on the back surface of the first print medium. Writing to the memory 13C, the M component page memory 13M, and the Y component page memory 13Y is completed. At this time T11, the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y store all the data in the color components corresponding to the image data to be printed. Will be.

  At time T11, the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the K component image data from the K component page memory 13K in the reverse direction. After that, until the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from High to Low (until time T15), the image controller 11 stores the K component image from the K component page memory 13K. Read data. As a result, all of the K component image data is read out.

  The K component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the K component station 228K in the printer engine 5 to print the K component. Done. The printing of the K component is performed as a 180-degree rotated image. In addition, a 0 degree rotated image is printed at the time of front side printing, and a 180 degree rotated image is printed at the time of back side printing, thereby aligning the vertical direction of the image printed on the front side of the print medium and the image printed on the back side. Will be.

  When the image controller 11 reads the K component image data from the K component page memory 13K, the image controller 11 erases the corresponding data in order from the K component page memory 13K immediately after the reading. As a result, the area used for storage in the K component page memory 13K decreases as the K component image data is read, in other words, the free capacity of the K component page memory 13K increases. .

  When the time T11 passes and the time T12 is reached, the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the C component image data from the C component page memory 13C in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from High to Low (until time T16), the image controller 11 stores the C component image from the C component page memory 13C. Read data. As a result, all of the C component image data is read out.

  The C component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the C component station 228C in the printer engine 5 to print the C component. Done. The C component printing is performed as a 180-degree rotated image in the same manner as the K component printing.

  When the image controller 11 reads the C component image data from the C component page memory 13C, the image controller 11 erases the corresponding data in order from the C component page memory 13C immediately after the reading. As a result, the area used for storage in the C component page memory 13C decreases as the C component image data is read, in other words, the free capacity of the C component page memory 13C increases. .

  When the time T12 passes and the time T13 is reached, the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the M component image data from the M component page memory 13M in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from High to Low (until time T18), the image controller 11 stores the M component image from the M component page memory 13M. Read data. As a result, all of the M component image data is read out.

  The M component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the M component station 228M in the printer engine 5 to print the M component. Done. The printing of the M component is performed as a 180-degree rotated image similarly to the printing of the K component and the C component.

  When the image controller 11 reads M component image data from the M component page memory 13M, the image controller 11 erases the corresponding data in order from the M component page memory 13M immediately after the reading. As a result, the area used for storage in the M component page memory 13M decreases as the M component image data is read, in other words, the free capacity of the M component page memory 13M increases. .

  When the time T13 has passed and the time T14 has passed, the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the Y component image data from the Y component page memory 13Y in the reverse direction. After that, until the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from High to Low (until time T19), the image controller 11 stores the Y component image from the Y component page memory 13Y. Read data. As a result, all of the Y component image data is read out.

  The Y component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the Y component station 228Y in the printer engine 5 to print the Y component. Done. The printing of the Y component is performed as a 180-degree rotated image, similarly to the printing of the K component, the C component, and the M component.

  When the image controller 11 reads the Y component image data from the Y component page memory 13Y, the image controller 11 erases the corresponding data sequentially from the Y component page memory 13Y immediately after the reading. As a result, the area used for storage in the Y component page memory 13Y decreases as the Y component image data is read, in other words, the free capacity of the Y component page memory 13Y increases. .

  As described above, the K component image, the C component image, the M component image, and the Y component image are printed as a 180-degree rotated image on the print medium, thereby performing color printing on the back surface of the first print medium. Is done.

(Third step)
At time T17, the image controller 11 sends image data to be printed on the surface of the second print medium to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y. To start writing in the opposite direction. Here, the time T17 is a time between the time T16 and the time T18 described above, and the timing at which the image data in the second step still remains in the M component page memory 13M and the Y component page memory 13Y. Become. In other words, during the time between time T17 and time T19, data reading and writing are simultaneously performed in the M component page memory 13M and the Y component page memory 13Y. By performing such processing, as described above, for example, it is possible to improve the processing speed as compared with the case of performing writing after data reading is completely completed. Here, the reason why there is no problem even if data reading and writing are simultaneously performed in the page memory 13 is the same as described above.

  Thereafter, at a time T20 after the time T19 when reading of the image data is completed in the second step, all the K component page memories 13K and C component pages of the image data to be printed on the surface of the second print medium. Writing to the memory 13C, the M component page memory 13M, and the Y component page memory 13Y is completed. At the timing of this time T20, the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y store all data of the image data to be printed. become.

  At time T20, the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the K component image data from the K component page memory 13K in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from High to Low (until time T24), the image controller 11 stores the K component image from the K component page memory 13K. Read data. As a result, all of the K component image data is read out.

  The K component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the K component station 228K in the printer engine 5 to print the K component. Done. The printing of the K component is performed so that the leading side is above the image of the image data in the print medium conveyance direction at the time of printing, that is, as a 0-degree rotated image.

  When the image controller 11 reads the K component image data from the K component page memory 13K, the image controller 11 erases the corresponding data in order from the K component page memory 13K immediately after the reading. As a result, the area used for storage in the K component page memory 13K decreases as the K component image data is read, in other words, the free capacity of the K component page memory 13K increases. .

  When the time T20 passes and the time T21 is reached, the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the C component image data from the C component page memory 13C in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from High to Low (until time T25), the image controller 11 stores the C component image from the C component page memory 13C. Read data. As a result, all of the C component image data is read out.

  The C component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the C component station 228C in the printer engine 5 to print the C component. Done. The printing of the C component is performed as a 0-degree rotated image, similarly to the printing of the K component.

  When the image controller 11 reads the C component image data from the C component page memory 13C, the image controller 11 erases the corresponding data in order from the C component page memory 13C immediately after the reading. As a result, the area used for storage in the C component page memory 13C decreases as the C component image data is read, in other words, the free capacity of the C component page memory 13C increases. .

  When the time T21 passes and the time T22 is reached, the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the M component image data from the M component page memory 13M in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from High to Low (until time T27), the image controller 11 stores the M component image from the M component page memory 13M. Read data. As a result, all of the M component image data is read out.

  The M component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the M component station 228M in the printer engine 5 to print the M component. Done. The printing of the M component is performed as a 0-degree rotated image, similarly to the printing of the K component and the C component.

  When the image controller 11 reads M component image data from the M component page memory 13M, the image controller 11 erases the corresponding data in order from the M component page memory 13M immediately after the reading. As a result, the area used for storage in the M component page memory 13M decreases as the M component image data is read, in other words, the free capacity of the M component page memory 13M increases. .

  When time T22 passes and time T23 is reached, the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the Y component image data from the Y component page memory 13Y in the reverse direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from High to Low (until time T28), the image controller 11 stores the Y component image from the Y component page memory 13Y. Read data. As a result, all of the Y component image data is read out.

  The Y component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the Y component station 228Y in the printer engine 5 to print the Y component. Done. The printing of the Y component is performed as a 0-degree rotated image, similarly to the printing of the K component, the C component, and the M component.

  When the image controller 11 reads the Y component image data from the Y component page memory 13Y, the image controller 11 erases the corresponding data sequentially from the Y component page memory 13Y immediately after the reading. As a result, the area used for storage in the Y component page memory 13Y decreases as the Y component image data is read, in other words, the free capacity of the Y component page memory 13Y increases. .

  As described above, the K component image, the C component image, the M component image, and the Y component image are printed as a 0-degree rotated image on the print medium, thereby performing color printing on the surface of the second print medium. Is done.

(Fourth step)
At time T26, the image controller 11 sends image data to be printed on the back surface of the second print medium to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y. To start writing in the opposite direction. Here, the time T26 is a time between the time T25 and the time T27 described above, and the timing at which the image data in the third step still remains in the M component page memory 13M and the Y component page memory 13Y. Become. That is, during the time between time T26 and time T29, data reading and writing are performed simultaneously in the M component page memory 13M and the Y component page memory 13Y. By performing such processing, the processing speed can be improved as compared with, for example, the case where writing is performed after data reading is completely completed. Here, the reason why there is no problem even if data reading and writing are simultaneously performed in the page memory 13 is the same as described above.

  Thereafter, at a time T29 after the time T28 when the reading of the image data is completed in the third step, all the K component page memories 13K and C component pages of the image data to be printed on the back surface of the second print medium. Writing to the memory 13C, the M component page memory 13M, and the Y component page memory 13Y is completed. At the timing of time T29, the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y store all data of the image data to be printed. become.

  At time T29, the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the K component image data from the K component page memory 13K in the forward direction. After that, until the system controller 9 changes the SYNC signal of VSYNC_K transmitted to the image controller 11 from High to Low (until time T33), the image controller 11 stores the K component image from the K component page memory 13K. Read data. As a result, all of the K component image data is read out.

  The K component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the K component station 228K in the printer engine 5 to print the K component. Done. The printing of the K component is performed as a 180-degree rotated image. In this way, in printing on the second print medium, printing on the front side is performed with a 0-degree rotated image, and printing on the back side is performed with a 180-degree rotated image, whereby an image printed on the front side of the print medium, The vertical direction with the image printed on the back side is aligned.

  When the image controller 11 reads the K component image data from the K component page memory 13K, the image controller 11 erases the corresponding data in order from the K component page memory 13K immediately after the reading. As a result, the area used for storage in the K component page memory 13K decreases as the K component image data is read, in other words, the free capacity of the K component page memory 13K increases. .

  When time T29 passes and time T30 is reached, the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the C component image data from the C component page memory 13C in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_C transmitted to the image controller 11 from High to Low (until time T34), the image controller 11 stores the C component image from the C component page memory 13C. Read data. As a result, all of the C component image data is read out.

  The C component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the C component station 228C in the printer engine 5 to print the C component. Done. The C component printing is performed as a 180-degree rotated image in the same manner as the K component printing.

  When the image controller 11 reads the C component image data from the C component page memory 13C, the image controller 11 erases the corresponding data in order from the C component page memory 13C immediately after the reading. As a result, the area used for storage in the C component page memory 13C decreases as the C component image data is read, in other words, the free capacity of the C component page memory 13C increases. .

  When the time T30 passes and the time T31 is reached, the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the M component image data from the M component page memory 13M in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_M transmitted to the image controller 11 from High to Low (until time T36), the image controller 11 stores the M component image from the M component page memory 13M. Read data. As a result, all of the M component image data is read out.

  The M component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the M component station 228M in the printer engine 5 to print the M component. Done. The printing of the M component is performed as a 180-degree rotated image similarly to the printing of the K component and the C component.

  When the image controller 11 reads M component image data from the M component page memory 13M, the image controller 11 erases the corresponding data in order from the M component page memory 13M immediately after the reading. As a result, the area used for storage in the M component page memory 13M decreases as the M component image data is read, in other words, the free capacity of the M component page memory 13M increases. .

  When time T31 has passed and time T32 has elapsed, the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from Low to High. Accordingly, the image controller 11 starts reading the Y component image data from the Y component page memory 13Y in the forward direction. Thereafter, until the system controller 9 changes the SYNC signal of VSYNC_Y transmitted to the image controller 11 from High to Low (until time T37), the image controller 11 stores the Y component image from the Y component page memory 13Y. Read data. As a result, all of the Y component image data is read out.

  The Y component image data read by the image controller 11 is subjected to image processing by the image processing LSI 10 as necessary, and then transmitted to the Y component station 228Y in the printer engine 5 to print the Y component. Done. The printing of the Y component is performed as a 180-degree rotated image, similarly to the printing of the K component, the C component, and the M component.

  When the image controller 11 reads the Y component image data from the Y component page memory 13Y, the image controller 11 erases the corresponding data sequentially from the Y component page memory 13Y immediately after the reading. As a result, the area used for storage in the Y component page memory 13Y decreases as the Y component image data is read, in other words, the free capacity of the Y component page memory 13Y increases. .

  As described above, the K component image, the C component image, the M component image, and the Y component image are printed as 180-degree rotated images on the print medium, whereby color printing is performed on the back surface of the second print medium. Is done.

(Print processing example 4: separate plane method, small paper space)
Next, see FIG. 4 for processing when image data of each color component exists independently from each other for one image and printing on the front surface and the back surface is not performed at equal intervals. While explaining. Also in this process, similarly to the above-described print processing example 3, front and back double-sided printing is performed on two print media by the first to fourth steps.

  In the print processing example 3, the purpose is to simplify the control by printing the front and back surfaces at equal intervals. However, in the print processing example 4, the front and back surfaces are printed as much as possible. The object is to increase the printing processing speed by controlling to perform it quickly.

  The print processing example 4 is different from the above-described print processing example 3 in the processing in the first step and the third step, and the other processing is the same. Hereinafter, only processing different from print processing example 3 will be described.

(First step)
First, under the control of the image controller 11, writing of image data to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y is started at time T1. In this first step, image data is written to the K component page memory 13K, C component page memory 13C, M component page memory 13M, and Y component page memory 13Y in the forward direction and read out in the forward direction. The data is written in the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y sequentially from the upper left data. At time T4, the writing of all the image data to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y is completed.

  Here, in the first step, the image data of each color component is read in the positive direction from the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y. It has become. That is, the writing direction and the reading direction for the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y are the same. In other words, in the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y, the order in which writing is performed and the order in which reading is performed are the same. Therefore, since it is possible to sequentially read from the memory area in which writing has been completed, an image is output to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y. Reading can be performed before all writing of data is completed.

  In this print processing example 4, by using this, at a time T2 that is a predetermined time after the time T1 at which image data writing starts and before the time T4 at which image data writing ends. The readout of the K component image data is started in the positive direction. Thereafter, reading of image data of the C component at time T3, the M component at time T5, and the Y component at time T6 is started.

(Third step)
After the second step, under the control of the image controller 11, writing of image data to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y is started at time T11. Is done. In this third step, the writing of image data to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y is performed in the reverse direction, and the reading is performed in the reverse direction. The data is written to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y sequentially from the upper left data. At time T14, the writing of all the image data to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y is completed.

  Here, in the third step, the image data of each color component is read in the reverse direction from the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y. It has become. That is, the writing direction and the reading direction for the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y are the same. That is, as in the first step, it is possible to perform reading sequentially from the memory area where writing has been completed, so the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and Y Reading can be performed before all writing of image data to the component page memory 13Y is completed.

  In this print processing example 4, by using this, at a time T12 that is a predetermined time after the time T11 when the writing of the image data is started and before the time T14 when the writing of the image data is finished. The readout of the K component image data is started in the reverse direction. Thereafter, reading of image data of the C component at time T13, the M component at time T15, and the Y component at time T16 is started.

  As described above, regarding the first step, in the print processing example 3, the reading of the K component image data is performed from the time when the writing of the image data is completed. The reading of the K component image data is started at a time T2 before the time T4 at which the writing of the image data ends. Regarding the third step, in the print processing example 3, the reading of the K component image data is performed from the time when the writing of the image data is completed, but in the printing processing example 4, the image data is read out. At the time T12 before the time T14 when the writing ends, the reading of the K component image data is started. That is, according to the print processing example 4, in the first and third steps, it is possible to improve the print processing speed by the amount of time that the reading of the K component image data is started earlier.

(Print processing example 5: another plane method, minimum paper interval)
Next, a print processing example that can further increase the print processing speed than the print processing example 4 will be described with reference to FIG. Also in this process, similarly to the above-described print processing example 3, front and back double-sided printing is performed on two print media by the first to fourth steps.

  In the print processing example 4, the writing of image data to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y is all performed at the same timing. Therefore, the writing timing of the image data in each step is set in accordance with the reading from the Y component page memory 13Y where the completion of reading is the slowest.

  In contrast, in print processing example 5, image data is written to the K component page memory 13K, the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y at different timings. . In other words, the timing of starting writing to the page memory corresponding to each color component is set to be as early as possible in accordance with the reading status of the corresponding page memory. As a result, the print processing speed can be further increased as compared with the print processing example 4.

  Hereinafter, the timing of writing and reading to the K component page memory 13K will be described. Note that the start timings of the write and read timings for the C component page memory 13C, the M component page memory 13M, and the Y component page memory 13Y are shifted from the write and read timings for the K component page memory 13K. Only.

(First step)
First, under the control of the image controller 11, writing of image data to the K component page memory 13K is started at time T1. In this first step, the image data is written to the K component page memory 13K in the forward direction, so that the image data is written to the K component page memory 13K in order from the upper left data. At time T3, the writing of the image data to all the K component page memories 13K is completed.

  Here, in the first step, the image data of each color component is read from the K component page memory 13K in the positive direction. That is, the direction of writing to the K component page memory 13K matches the direction of reading. In other words, in the K component page memory 13K, the order in which writing is performed and the order in which reading is performed are the same. Therefore, since it is possible to sequentially read from the memory area where the writing has been completed, it is possible to perform the reading before the writing of all the image data to the K component page memory 13K is completed.

  In this print processing example 5, by using this, at a time T2 that is a predetermined time after the time T1 at which image data writing starts and before the time T3 at which image data writing ends. The readout of the K component image data is started in the positive direction.

(Second step)
Thereafter, at time T4, under the control of the image controller 11, writing of image data in the positive direction to the K component page memory 13K is started. Here, the time T4 is a time before the time T5 which is the completion time of reading the K component image data started at the time T2. That is, during time T4 to time T5, reading and writing are simultaneously performed on the K component page memory 13K. Similarly to the above, since the writing direction and the reading direction with respect to the K component page memory 13K coincide with each other, it is possible to perform writing sequentially from the memory area where the reading is completed. Is realized.

  After that, at time T6 when writing of image data started from time T4 ends, reading of K component image data starts in the reverse direction, and reading ends at time T11.

(Third step)
Thereafter, writing of image data to the K component page memory 13K is started at time T11. In this third step, the image data is written to the K component page memory 13K in the reverse direction, so that the image data is written to the K component page memory 13K in order from the lower right data. At time T13, the writing of the image data to all the K component page memories 13K is completed.

  Here, in the third step, the image data of each color component is read from the K component page memory 13K in the reverse direction. That is, the direction of writing to the K component page memory 13K matches the direction of reading. Therefore, since it is possible to sequentially read from the memory area where the writing has been completed, it is possible to perform the reading before the writing of all the image data to the K component page memory 13K is completed.

  In this print processing example 5, by using this, at a time T12 that is a predetermined time after the time T11 at which image data writing is started and before the time T13 at which image data writing ends. The readout of the K component image data is started in the reverse direction.

(Fourth step)
After that, at time T14, writing of image data in the reverse direction to the K component page memory 13K is started under the control of the image controller 11. Here, the time T14 is a time prior to the time T15, which is the completion time of reading the K component image data started at the time T12. That is, during time T14 to time T15, reading and writing are simultaneously performed on the K component page memory 13K. Similarly to the above, since the writing direction and the reading direction with respect to the K component page memory 13K coincide with each other, it is possible to perform writing sequentially from the memory area where the reading is completed. Is realized.

  After that, at time T16 when the writing of the image data started from time T14 ends, reading of the K component image data starts in the reverse direction.

(Print processing example 6: printing multiple sheets continuously)
When performing double-sided printing, as described above, after the printing on the front surface is completed, the back and front of the print medium is reversed by the switchback mechanism and returned to the image forming unit 210. That is, it takes time required for the reversing process and the conveying process of the print medium from the completion of the front surface printing to the back surface printing. Therefore, in the case where a plurality of duplex printings are performed, the printing of the first sheet is completed and the second sheet is printed while the first printing medium is reversed and transported. It may be. As a result, it is possible to eliminate idle time during the reversing / conveying process of the print medium, and it is possible to improve the printing process speed.

  FIG. 6A shows a change in the amount of data stored in the page memory 13 when two sheets of the front surface and the back surface are continuously printed as described above. In the example shown in FIG. 6A, the process is based on the process in the print process example 1 described above.

  In the first step, the front surface is printed by a process corresponding to the first step in the print processing example 1. In the second step, the surface is printed by the process corresponding to the first step in the print processing example 1 in the same manner. In the third step, the back side is printed by the process corresponding to the second step in the print processing example 1. In the fourth step, the back side is printed by the process corresponding to the fourth step in the print processing example 1. Thereafter, these first to fourth steps are repeated.

  In the first step, reading from the page memory 13 is performed in the forward direction, while in the second step, writing to the page memory 13 is performed in the forward direction. That is, in the page memory 13, the writing direction and the reading direction coincide with each other, so that it is possible to perform writing to the page memory 13 before all the image data is completely read. ing. Thereby, the processing speed is improved.

  In addition, since the reading direction (positive direction) in the second step matches the writing direction (positive direction) in the third step, the image is stored in the page memory 13 in the same manner as described above. Writing can be performed before all the data reading is completed. Thereby, the processing speed is improved.

  In addition, since the reading direction (reverse direction) in the third step and the writing direction (reverse direction) in the fourth step are the same, the image is stored in the page memory 13 in the same manner as described above. Writing can be performed before all the data reading is completed. Thereby, the processing speed is improved.

  In addition, since the reading direction (positive direction) in the fourth step matches the writing direction (positive direction) in the first step of the next cycle, similarly to the above, the page memory 13 On the other hand, writing can be performed before all reading of image data is completed. Thereby, the processing speed is improved.

  As described above, according to the example shown in FIG. 6A, the reading and writing directions with respect to the page memory 13 in each step coincide with each other, so that the processing speed can be improved by performing reading and writing simultaneously. It has been.

  FIG. 6B shows a change in the amount of data stored in the page memory 13 when three front and back prints are performed continuously. The example shown in FIG. 6B is also based on the processing in the print processing example 1 described above.

  In the first to third steps, the surface is printed by the process corresponding to the first step in the print processing example 1. In the fourth step, the back side is printed by the process corresponding to the second step in the print processing example 1 in the same manner. In the fifth step, the back side is printed by the process corresponding to the fourth step in the print processing example 1 in the same manner. In the sixth step, the back side is printed by the process corresponding to the second step in the print processing example 1 in the same manner. In the seventh to ninth steps, the surface is printed by the process corresponding to the third step in the print processing example 1. In the tenth step, the back side is printed by the process corresponding to the fourth step in the print processing example 1 in the same manner. In the eleventh step, the back side is printed by the process corresponding to the second step in the print processing example 1 in the same manner. In the twelfth step, the back side is printed by the process corresponding to the fourth step in the print processing example 1 in the same manner. Thereafter, these first to twelfth steps are repeated.

  Also in this example, since the reading and writing directions with respect to the page memory 13 in each step coincide with each other, the processing speed is improved by simultaneously performing reading and writing.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

  As shown in the present embodiment, the image forming apparatus according to the present invention is an MFP that performs print processing of a print job transmitted from a host, prints an image read by a scanner unit, or a copy having only a copy function. It can be applied to a printer and a printer having only a print function. Further, the image processing apparatus according to the present invention can be applied as a printer controller built in the various image forming apparatuses as described above.

FIG. 10 is a diagram illustrating state transitions such as writing to and reading from a page memory in a print processing example 1 performed by the MFP according to the embodiment. FIG. 10 is a diagram illustrating state transitions such as writing to and reading from a page memory in a print processing example 2 performed by the MFP according to the embodiment. FIG. 10 is a diagram illustrating state transitions such as writing to and reading from a page memory in a print processing example 3 performed by the MFP according to the embodiment. FIG. 10 is a diagram illustrating state transitions such as writing to and reading from a page memory in a print processing example 4 performed by the MFP according to the embodiment. FIG. 10 is a diagram illustrating state transitions such as writing to and reading from a page memory in a print processing example 5 performed by the MFP according to the embodiment. (A) and (b) are diagrams showing the state transition of the data change in the page memory in the print processing example 6 performed by the MFP according to the present embodiment. 1 is a block diagram illustrating a schematic configuration of a print system according to an embodiment. FIG. 2 is a block diagram illustrating a schematic configuration of the print system in the case where a page memory for each color component corresponding to each color component image data is provided. FIG. 2 is a cross-sectional view illustrating a schematic configuration of a printer engine included in the MFP according to the embodiment.

Explanation of symbols

1 MFP (image forming device)
2 Host 3 Printer controller (image processing device)
4 Scanner unit 5 Printer engine 7 HDD
8 I / O controller 9 System controller (processing control means)
9a System memory 9b CPU
11 Image controller (storage unit control means)
12 RAM (data storage unit)
13 page memory 13C C component page memory 13K K component page memory 13M M component page memory 13Y Y component page memory 210 Image forming unit 211 Paper feed unit 221 Switchback transport path 228 Image forming station 228C C component station 228K K component station 228M M Component station 228Y Y component station

Claims (11)

In an image processing apparatus that outputs data to be imaged to a printer engine,
A data storage unit for storing the data;
Storage unit control means for performing processing for writing data to be image-formed to the data storage unit, and processing for reading data to be image-formed from the data storage unit and outputting the data to the printer engine;
Processing control means for controlling processing by the storage control means,
In a period in which data included in one unit image is read from the data storage unit, a process of writing data included in an image to be imaged next to the data storage unit is performed. An image processing apparatus, wherein the processing control means controls the storage section control means. The first direction and the second direction opposite to the first direction are directions in which data included in one unit image to be imaged is sequentially written or read out from the data storage unit. Exist and
The reading direction in which the data included in one unit image is read from the data storage unit, and the data included in the image to be imaged next in the reading period are stored in the data storage unit. The image processing apparatus according to claim 1, wherein the processing control unit controls the storage unit control unit so that a writing direction written in the same direction is matched.   The processing control unit controls the storage unit control unit so that the data storage unit sequentially reads from the data that has been written during a period in which the data included in one unit image is written. The image processing apparatus according to claim 1, wherein: The first direction and the second direction opposite to the first direction are directions in which data included in one unit image to be imaged is sequentially written or read out from the data storage unit. Exist and
The writing direction in which the data included in one unit image is written from the data storage unit and the reading direction in which the data that has been written in the writing period are being read are matched. The image processing apparatus according to claim 3, wherein the processing control unit controls the storage unit control unit. The data to be image-formed is data in which data of a plurality of color components is included in data corresponding to one unit of image,
The image processing apparatus according to claim 1, wherein the storage control unit controls the processing control unit so that the data of each color component is read out separately and output to the printer engine. The data to be image-formed is data in which the data of each color component is independent from each other for one unit of image,
The data storage unit includes a plurality of color component data storage units corresponding to each color component,
The storage unit control means writes the data of each color component in the corresponding color component data storage unit, and reads out the data of each color component from each color component data storage unit and outputs them to the printer engine. The image processing apparatus according to claim 1, wherein the processing control unit controls the image processing apparatus. The processing control means, with respect to the storage control means,
A first step of writing data included in one unit of image to be imaged to the data storage unit in the first direction and reading the data in the first direction;
A second step of writing data included in one unit image to be imaged to the data storage unit in the first direction and reading the data in the second direction;
A third step of writing data contained in one unit of image to be imaged next to the data storage unit in the second direction and reading the data in the second direction;
Further, data included in one unit image to be imaged next is written in the data storage unit in the second direction, and the fourth step of reading the data in the first direction is repeated. The image processing apparatus according to claim 2, wherein control is performed so that The processing control means, with respect to the storage control means,
The image processing apparatus according to claim 7, wherein each of the steps is controlled to be repeated a predetermined number of times.   An image forming apparatus comprising: the image processing apparatus according to claim 1; and a printer engine. In an image processing method in an image processing apparatus that outputs data to be imaged to a printer engine,
A process of writing data to be image-formed to a data storage unit for storing the data, and a process of reading data to be image-formed from the data storage unit and outputting the data to the printer engine,
In a period in which data included in one unit image is read from the data storage unit, a process of writing data included in an image to be imaged next to the data storage unit is performed. Image processing method.   An image processing program for causing a computer to realize processing control means included in the image processing apparatus according to any one of claims 1 to 8.

Images