JP2012148434A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the load of a controller CPU.SOLUTION: An image forming apparatus has: an image forming means for forming an image based on image data; a first memory means for storing the acquired image data; a second memory means for storing the transferred image data, which is obtained by transferring the image data stored in the first memory means; an output means which requests image data stored in the second memory means and which outputs the requested image data to the image forming means; a first measurement means for measuring the number of output lines being the least unit of the image data which is output from the output means to the image forming means; a second measurement means for measuring the number of transfer lines of image data which is transferred from the first memory means to the second memory means; and an instruction means for making the output means request the image data stored in the second memory means, based on the number of output lines and the number of transfer lines.

Description

  The present invention relates to an image forming apparatus.

  For example, in an inkjet image forming apparatus, when there is continuous blank image data that exceeds the width that the print head prints by reciprocating movement, the print head reciprocates until there is next non-blank image data. Has been proposed, and so-called skip processing is performed (for example, see Patent Document 1).

  Also, for example, when printing a long image, there is a problem that the output image transfer speed overtakes the speed at which the image stored in the HDD is transferred to the memory as a result of the skip processing. May occur. As a technique for solving such a problem, Patent Document 2 is proposed.

  FIG. 1 shows a system configuration example of an image forming apparatus described in Patent Document 2. Image data acquired by reading a document is temporarily stored in the HDD 103. Then, based on the control of the image transfer apparatus 102, the stored image data is divided into bands and developed in the memory 104 by predetermined bands.

  When image data for one band is expanded from the HDD 103 to the memory 104, the image transfer apparatus 102 transmits an interrupt signal to the controller CPU 101. The controller CPU can recognize the number of bands of image data developed (stored) in the memory 104 by counting the interrupt signals.

  When the predetermined number of bands of image data are developed in the memory 104, the controller CPU 101 transmits a request permission signal to the image output apparatus 202 via the image transfer apparatus 102. When the image output device 202 receives the request permission signal, the image output device 202 transmits a request signal to the image transfer device 102 to request image data of a predetermined number of bands stored in the memory. The requested image data is transferred to the plotter 203 via the image output device 202. The plotter 203 prints on the paper based on the transferred image data.

  However, in the technique described in Patent Document 2, every time one band is developed from the HDD 103 to the memory 104, the image transfer apparatus 102 transmits an interrupt signal to the memory controller CPU101.

  Accordingly, when the band size of the image data transferred to the image output apparatus 202 is small, the number of image data bands developed from the HDD 103 to the memory 104 increases, so that many interrupt signals are generated and the controller CPU There is a problem that the load increases.

  Therefore, in view of such a problem, an object of the present invention is to reduce the load on the controller CPU.

  To achieve the above object, based on the image data, image forming means for forming an image, first storage means for storing the acquired image data, and image data stored in the first storage means are transferred, Second storage means for storing the transferred image data; output means for requesting the image data stored in the second storage means; and outputting the requested image data to the image forming means; First measurement means for measuring the number of output lines, which is the minimum unit of image data, output from the output means to the image forming means, and transfer of image data transferred from the first storage means to the second storage means Second measuring means for measuring the number of lines, instruction means for causing the output means to request image data stored in the second storage means based on the number of output lines and the number of transfer lines; To provide an image forming apparatus, comprising.

  According to the image forming apparatus of the present invention, the load on the controller CPU can be reduced.

FIG. 6 is a diagram illustrating a functional configuration example of a conventional image forming apparatus. 1 is a diagram illustrating a functional configuration example of an image forming apparatus according to an embodiment. FIG. 3 is a diagram illustrating a more detailed functional configuration example of the image forming apparatus according to the present exemplary embodiment. The figure which showed memory etc. typically. FIG. 3 is a diagram illustrating a processing flow of the image forming apparatus according to the present exemplary embodiment. The figure which showed the processing flow of another embodiment (the 1). FIG. 6 is a diagram illustrating a functional configuration example of an image forming apparatus according to another embodiment. The figure which showed the processing flow of another embodiment (the 2).

  Examples of the image forming apparatus include a copying machine such as a printer, a facsimile machine, and an ink jet recording apparatus, and a complex machine of these. The recording medium is, for example, a substrate, paper, continuous paper, thread, fiber, leather, metal, plastic, glass, wood, ceramics, or the like.

Each embodiment will be described below. In addition, the same number is given to the component having the same function and the process of performing the same process, and the duplicate description is omitted.
[Embodiment 1]
The image forming apparatus of Embodiment 1 will be described. FIG. 2 shows a functional configuration example of the image forming apparatus according to the first embodiment. The image forming apparatus according to the first embodiment is roughly divided into an engine unit 300 and a system controller unit 400.

  Further, the engine unit 300 includes an image forming unit 2, an image output unit 20, and an engine CPU 60. The system controller unit 400 includes an image transfer unit 40, a first storage unit 30, a second storage unit 32, a network I / F 62, and a controller CPU 64. Hereinafter, the first storage unit 30 is referred to as an HDD 30. The first storage unit 30 may be an SSD (Solid State Drive) or the like. The second storage means 32 is a memory 32.

  The processing of each component will be briefly described. The controller CPU 64 is a CPU that controls the system controller unit 400. The controller CPU 64 performs setting of the operation mode of the image transfer unit 40, an activation instruction, address management of the memory 32, and the like. The image transfer unit 40 transfers image data to the image forming unit 2, performs image processing, and transfers images between devices such as the HDD 30 and the network I / F 62. The HDD 30 stores image data. The memory 32 stores the image data stored in the HDD 30.

  The engine CPU 60 is a CPU that controls the engine unit 300. The image output unit 20 acquires image data from the system controller unit 400 and transfers the image data to the image forming unit 2. The image forming unit 2 forms an image based on the image data. The image forming unit 2 is, for example, a recording head or a plotter. The network I / F 62 acquires image data from the outside.

  FIG. 3 shows further detailed configuration examples of the image output unit 20 and the image transfer unit 40. In FIG. 3, for simplification of the drawing, the description of the engine CPU 60, the controller CPU 64, and the network I / F 62 shown in FIG. 2 is omitted.

  First, the HDD 30 and the memory 32 will be described. The HDD 30 is a large capacity storage means, and the storage capacity of the memory 32 is smaller than the storage capacity of the HDD 30. A user sets a document on the image forming apparatus, and reading means (not shown) reads the document to acquire image data. The image data acquired by the reading unit is temporarily stored in the HDD 30. Alternatively, the user may store image data transmitted from an external terminal (for example, a PC) in the HDD 30. Transfer to the HDD 30 and the memory 32 is performed by the storage control means 24. The storage control means 24 is also referred to as “HDD DMAC”. Further, the memory 32 has a pair of toggle buffers for each CYMK version (for example, each color).

  FIG. 4 shows a schematic diagram of image data stored in the memory 32 from the HDD 30. The HDD 30 stores image data for one page for each band divided into a predetermined number. Here, the band is an area obtained by dividing image data of a document with a predetermined width in the sub-scanning direction, and the band is configured by a predetermined number of lines. One line refers to a range in the sub-scanning direction in which the image forming unit 2 can record on a sheet with the sheet stopped. The sub-scanning direction refers to the paper transport direction. In addition, when the capacity of the memory 32 is insufficient, when all the image data for one page cannot be expanded in the memory 32, the image data for one page is expanded while partially expanding from the HDD 30 to the memory 32. By transferring the image to the image forming unit 2 by the image transfer unit 40 before the development is completed, the shortage of the capacity of the memory 32 can be solved. The reason why the image data stored in the HDD 30 is stored in the memory 32 is that all the image data cannot be stored because the storage capacity is small.

  The output unit 12 requests the image data stored in the memory 32 by transmitting an image data request signal to the transfer unit 26. The transfer means 26 is also called output DMAC. The image data request signal requests a predetermined number of lines of image data in the memory 32. The image data request signal also includes information indicating the value of the predetermined number of lines of image data to be requested. Yes. When receiving the image data request signal, the transfer unit 26 transfers the image data in the memory 32 for the lines included in the image data request signal to the output unit 12.

  The first measuring unit 4 measures the number of lines of image data (hereinafter referred to as “number of output lines”) output from the output unit 12 to the image forming unit 2 (the output has been completed). That is, the first measuring means 4 measures the total number of lines of image data that has been output. As an example of a method for measuring the number of output lines of the first measuring unit 4, the transfer amount of the image data output to the image forming unit 2 by the output unit 12 is observed, and converted from the size of the image data in the main scanning direction to the number of lines. Therefore, it is only necessary to count.

  The second measuring means 22 measures the number of lines (number of transfer lines) of the image data transferred (transfer finished) from the HDD 30 (first storage means) to the memory 32 (second storage means). That is, the second measuring means 22 measures the total number of lines of image data that has been transferred. Moreover, the 1st measurement means 4, the 2nd measurement means 22, and the comparison means 6 are comprised with hardware.

  Next, the main processing flow of the image forming apparatus is shown in FIG. A main processing flow of the image forming apparatus according to the first exemplary embodiment will be described with reference to FIGS. 3 and 5. The processing flow in the figure explains the flow of processing from the time when image data for one page is output from the output means 12 to the image forming means 2. Processing until output to the means 2 may be performed.

  First, the first measuring means 4 and the second measuring means 22 are initialized (step S1). Here, the initialization means resetting the count values of the first measuring means 4 and the second measuring means 22 to “0”.

  Next, the transfer line number request unit 10 requests the value of the transfer line number by transmitting a transfer line number request signal to the second measuring unit 22. As described above, the number of transfer lines is the total number of lines of image data transferred from the HDD 30 to the memory 32, and is measured by the second measuring unit 22. When receiving the transfer line number request signal, the second measuring means 22 transmits the transfer line number at the time of reception to the transfer line number request means 10. Then, the comparison unit 6 acquires the number of transfer lines via the transfer line request unit 10 (step S2). The transfer line number requesting means 10 may be performed according to an instruction from the comparison means 6, or the transfer line number requesting means 10 may be performed voluntarily every predetermined time.

  Next, the comparison unit 6 acquires the number of output lines from the first measurement unit 4 (step S4). As described above, the number of output lines is the total number of lines of image data that have been output from the output unit 12 to the image forming unit 2. The transfer line number acquisition process and the output line number acquisition process of the comparison unit 6 are performed in parallel.

  The instruction unit 8 causes the output unit 12 to request image data stored in the memory 32 based on the number of output lines and the number of transfer lines. More specifically, the instruction unit 8 transmits the image data request instruction signal to the output unit 12 to cause the output unit 12 to transmit the image data request signal.

  In the first embodiment, based on the result of the comparison unit 6, the output unit 12 is requested for image data stored in the memory 32. In the example of FIG. 5, the comparison means 6 compares the number of transfer lines with the number of output lines (step S6). If the number of transfer lines> the number of output lines (Yes in step S6), the memory 32 stores image data for “number of transfer lines−number of output lines”. Therefore, the image data is transferred to the image output unit 20 by the predetermined number of lines out of the stored “number of transfer lines−number of output lines”. Specifically, the instruction unit 8 causes the output unit 12 to request image data for a predetermined number of lines among the image data for “number of transfer lines−number of output lines” in the memory 32 (step S10). . Here, the predetermined number of lines may be one line, two lines or more, or one or more band lines. The value of the predetermined number of lines is determined in advance, and the predetermined number of lines is stored in the HDD 30, the memory 32, or other storage means (not shown). In the first embodiment, a case where the output unit 12 requests image data in units of lines will be described. In the second embodiment, a case where the output unit 12 requests image data in band units will be described. Further, the instruction means 8 includes information on the number of lines of image data to be requested in the image data request instruction signal transmitted to the output means 12.

  When receiving the image data request signal, the transfer unit 26 extracts image data for a predetermined number of lines from the image data in the memory 32 and transfers the image data to the output unit 12. When the output unit 12 receives the requested number of lines of image data, the output unit 12 outputs the received image data to the image forming unit 2. Then, the image forming unit 2 forms an image based on the output image data. Then, the engine CPU 60 determines whether or not the number of output lines (number of output end lines) is equal to the number of lines of image data for one page (step S12). If the number of output lines is equal to the number of lines of image data for one page (Yes in step S12), it means that all of the image data for one page has been output to the image forming means 2, and the processing is terminated. On the other hand, the case where the number of output lines is not equal to the number of lines of image data for one page (No in step S12) means that the number of output lines <the number of lines of image data for one page, and thus the image for one page. As for the data, the image data for the line not output to the image forming means 2 is stored in the memory 32. Accordingly, in order to output the image data for the lines not output to the image forming unit 2 to the image forming unit 2, the process returns to step S 2 and step S 4, and all the image data for one page is transferred to the image forming unit 2. The process is repeated until it is output.

  If the comparison unit 6 determines in step S6 that the number of transfer lines is not greater than the number of output lines, that is, the number of transfer lines = the number of output lines (No in step S6), the memory 32 stores image data. Since it is not stored, it waits for a certain period of time (step S8), and thereafter, processes of steps S2 and S4 are performed. Since there is a high possibility that image data will be transferred from the HDD 30 to the memory 32 while waiting for a certain time, the processes in steps S2 and S4 are performed again.

As described above, in the image forming apparatus according to the first embodiment, the image stored in the memory 32 is calculated from the number of output lines measured by the first measuring unit 4 and the number of transfer lines measured by the second measuring unit 22. The image output unit 20 can recognize the number of data lines. Accordingly, the controller CPU 64 does not need to recognize the number of lines of image data stored in the memory 32, and the image transfer unit 40 does not need to transmit an interrupt signal to the controller CPU 64. Therefore, the load on the controller CPU can be reduced. In addition, unlike the technique described in Patent Document 2, the controller CPU 64 does not need to generate and transmit a request permission signal. From this point, the load on the controller CPU 64 can be reduced.
[Embodiment 2]
Next, the image forming apparatus according to the second embodiment will be described. In the image forming apparatus according to the first embodiment, the output unit 12 requests image data from the transfer unit 26 in units of lines. However, in the second embodiment, the output unit 12 requests the transfer unit 26. Request image data in band units. Since the image forming apparatus according to the second embodiment requests more image data than the image forming apparatus according to the first embodiment, the number of image data request processes from the image output unit 20 to the image transfer unit 40 is small. As a result, the processing time can be shortened.

  FIG. 6 shows a processing flow of the image forming apparatus according to the second embodiment. When the processes of steps S1, S2, and S4 are completed, the comparison unit 6 determines whether or not the number of transfer lines−the number of output lines ≧ the number of lines for a predetermined band (step S20). In the following, for simplicity of explanation, the predetermined band is one band, but two or more bands may be used. If the number of transfer lines−the number of output lines ≧ the number of lines for one band, it means that image data for one band or more is stored in the memory 32. Accordingly, when it is determined Yes in step S20, in step S22, the output unit 12 requests image data for one band from the transfer unit 26 (step S22). Then, the output unit 12 transfers the requested image data to the image forming unit 2.

  Then, the engine CPU 60 determines whether or not the number of lines per page−the number of output lines ≦ the number of lines in one band (step S24). The case where the number of lines per page−the number of output lines ≦ the number of lines per band (No in step S24) means that the number of lines per page−the number of output lines> the number of lines per band. In one page of image data, the number of lines of image data that has not yet been output to the image forming means 2 is greater than the number of lines in one band. Accordingly, the process returns to Steps S2 and S4 in order to output image data not yet output to the image forming unit 2 to the image forming unit 2.

  On the other hand, when the number of lines per page−the number of output lines ≦ the number of lines per band (Yes in step S24), (i) all image data for one page is output to the image forming unit 2. (Ii) the number of lines of image data that has not yet been output to the image forming means 2 is less than or equal to the number of lines in one band. There is. In particular, the case of (ii) means that, for example, if one band is composed of three lines, there are two lines of image data not output to the image forming means 2. Then, in the processes after step S26, the existing two lines of image data are output to the image forming means 2.

  Next, the transfer line request unit 10 requests the number of transfer lines from the second measuring unit 22. Then, the comparison unit 6 determines whether or not the number of transfer lines is equal to the number of lines of image data for one page (step S26). The fact that the number of transfer lines is equal to the number of lines of image data for one page (Yes in step S26) means that all of the image data for one page is stored in the memory 32. If Yes in step S26, the process proceeds to step S30.

  On the other hand, the fact that the number of transfer lines is not equal to the number of lines of image data for one page (No in step S26) means that there is still image data that has not been transferred to the memory 32 in one page of image data. That is. Therefore, in this case, the process waits until the image data stored in the HDD 30 is stored in the memory 32 (step S8).

  Accordingly, the output unit 12 requests the remaining image data stored in the memory 32 (that is, image data equal to or less than the number of lines in one band) from the transfer unit 26 (step S30). The output unit 12 acquires the requested image data. Then, the output unit 12 outputs the acquired image data to the image forming unit 2. Then, the engine CPU determines whether or not the number of output lines is equal to the number of lines of image data of one page (step S12). If the number of output lines is equal to the number of lines of image data for one page (Yes in step S12), it means that all the numbers of lines of image data for one page have been output, and the process is terminated. If the number of output lines is not the number of lines of image data of one page (No in step S12), that is, the number of output lines <the number of lines of image data of one page, and the number of output lines = 1 page. Wait until the image data becomes.

  According to the image forming apparatus of the second embodiment, the output unit 12 requests image data for each band. Therefore, compared with the image forming apparatus of the first embodiment, the number of transmissions of the image data request signal of the output unit 12 can be reduced, so that the processing time can be reduced.

In addition, since the image forming unit 2 normally performs image formation in units of bands, it is possible to omit the process of converting image data in units of lines into image data in units of bands.
[Embodiment 3]
Next, the image forming apparatus of Embodiment 3 will be described. The image output unit 20 according to the first embodiment requests image data stored in the memory 32 in units of lines, and the image output unit 20 according to the second embodiment uses the image data stored in the memory 32 as a band. This is requested in units.

  In the image forming apparatus according to the third embodiment, the output unit 12 requests all the image data currently stored in the memory 32. In other words, when the instruction unit 8 requests the output unit 12 to request the image data stored in the memory 32, the instruction unit 8 requests all the image data stored in the memory 32.

  FIG. 7 shows a functional configuration example of the image forming apparatus of the third embodiment, and FIG. 8 shows a processing flow of the image forming apparatus of the third embodiment. 7 is compared with FIG. 3 in that the first measuring means 4 shown in FIG. 3 is replaced with the third measuring means 50 shown in FIG. The third measuring means 50 is for the output means 12 to measure the total number of lines of image data that has been requested to the image transfer section 40. Hereinafter, the number of lines of image data for which the request has been completed is referred to as “requested number of lines”. The third measuring unit 50 measures the number of requested lines requested by the image data request instruction signal transmitted to the instruction unit 8.

  First, the second measuring means 22 and the third measuring means 50 are initialized (step S1). Here, the initialization means resetting the count values of the second measuring means 22 and the third measuring means 50 to “0”.

  Next, the comparison means 6 acquires the number of transfer lines via the transfer line request means 10 (step 42). The process of step S42 is the same process as step S2 shown in FIG. Further, the comparison unit 6 acquires the required number of lines from the third measurement unit 50 (step S44). Then, the comparison unit 6 compares whether or not the number of transfer lines> the number of requested lines (step S46).

  If the number of transfer lines> the number of requested lines (Yes in step S46), the image data for the lines stored in the memory 32 but not yet requested by the output means 12 (that is, “the number of transfer lines”). -Image data for "number of requested lines" is stored in the memory 32. Accordingly, the instruction unit 8 transmits an image data request instruction signal to the output unit 12 so as to request image data corresponding to “number of transfer lines−number of requested lines”.

  When the output unit 12 acquires image data corresponding to “the number of transfer lines−the number of requested lines” (that is, all image data currently stored in the memory 32), the acquired image data is sent to the image forming unit 2. Output.

  Then, the controller CPU 64 determines whether or not the required number of lines = the number of lines of image data of one page (step S52). The case where the requested number of lines = the number of lines of image data of one page (Yes in step S52) means that all the image data for one page has been requested and the output unit 12 has output to the image forming unit 2. The process is terminated.

  On the other hand, the case where the number of requested lines is not the number of lines of image data of one page (No in step S52) means that the number of requested lines <the number of lines of image data of one page. The image data not requested is stored in the memory 32. In this case, the process returns to steps S42 and S44. Moreover, although not shown, you may return to the process of step S50.

  If the comparison unit 6 determines in step S46 that the number of transfer lines> the number of requested lines (No in step S46), the number of transfer lines = the number of requested lines. This means that no image data is stored. Therefore, the process proceeds to step S52 without performing the process of step S50. Further, although not shown in FIG. 8, if No in step S <b> 46, the process may wait for a predetermined time and return to the processes in steps S <b> 42 and S <b> 44.

  According to the image forming apparatus of the third embodiment, the output unit 12 requests all image data currently stored in the second memory 32. Therefore, compared to the first and second embodiments, the number of requests from the output unit 12 to the transfer unit 26 can be further reduced, so that the processing time can be reduced.

In the third embodiment, processing is performed with the number of transfer lines and the number of requested lines. However, the number of output lines may be used instead of the number of requested lines. In this case, the processing flow in FIG. 8 is replaced from “number of requested lines” to “number of output lines”.
[Embodiment 4]
Next, an image forming apparatus according to Embodiment 4 will be described. In the image forming apparatuses according to the first to third embodiments, the output unit 12 requests image data from the image transfer unit 40 based on the image data request instruction signal from the instruction unit 8.

  However, all the image data of the document set by the user may be transferred to the memory 32 at a timing before the output unit 12 requests image data from the transfer unit 26, that is, at an early timing. In this case, the output unit 12 preferably requests the image data from the memory 32 directly without using the image data request instruction signal from the instruction unit 8. This is because the image output unit 20 (the transfer line request unit 10, the comparison unit 6, the first measurement unit 4, the second measurement unit 22, and the third measurement unit 40) does not need to perform processing, This is because the processing cost can be reduced.

  Specifically, the controller CPU 64 detects whether or not unit image data (for example, image data for one page or more of a document) is stored in the memory 32 as the detection unit 64. When the controller CPU 64 detects that image data for one page or more has been stored in the memory 32, it transmits an image data storage signal indicating that fact to the image forming means 2.

  When the image forming unit 2 receives the image data storage signal, the image forming unit 2 requests an image data request signal (image data is requested from the image transfer unit 40 or directly to the image transfer unit 40 via the output unit 12. Signal). Here, two examples of a method for determining the volume of requested image data by the image forming unit 2 will be described. First, the image forming unit 2 itself determines the required capacity of image data. For example, the image transfer unit 40 requests new image data corresponding to the amount of image data printed on the paper by the image forming unit 2. In the first method, image data can be efficiently acquired when the image forming unit 2 performs white skip.

  As a second technique, the image forming unit 2 requests the image transfer unit 40 by a predetermined line (or a predetermined band) every predetermined time. In the second method, it is not necessary to provide the image forming unit 2 with a function for determining the capacity of necessary image data.

  When the image transfer unit 40 receives the image transfer request signal, the image transfer unit 40 extracts the image data corresponding to the image transfer request signal from the memory 32 and transmits the extracted image data to the image forming unit 2.

  On the other hand, the controller CPU 64 stops processes other than the output unit 12 in the image output unit 20. Further, when the image forming unit 2 directly transmits an image data request signal to the image transfer unit 40, the output unit 12 is not necessary, so that the processing of all the components of the image output unit 20 is stopped. May be.

  According to the image forming apparatus of the fourth embodiment, if the image data of one or more pages of the document is expanded in the memory 32, the image forming unit 2 does not need the processing of the image output unit 20, and the image is output. Data can be requested from the image transfer unit 40. Therefore, the transfer line requesting means 10, the comparing means 6, the first measuring means 4, the second measuring means 22, and the third measuring means 40 do not need to perform processing, and the processing costs of these components can be reduced.

2 Image forming means 4 First measurement means 6 Comparison means 8 Instruction means 10 Transfer line number request means 12 Output means 22 Second measurement means 24 Storage control means 26 Transfer means

JP 2002-036528 A JP 2007-118238 A

Claims (4)

First storage means for storing acquired image data;
Second storage means for transferring the image data stored in the first storage means and storing the transferred image data;
Output means for requesting the image data stored in the second storage means and outputting the requested image data;
Image forming means for forming an image based on the image data output from the output means;
First measurement means for measuring the number of output lines of image data output from the output means to the image forming means;
Second measuring means for measuring the number of transfer lines of image data transferred from the first storage means to the second storage means;
An image forming apparatus comprising: an instruction unit that requests the output unit to request image data stored in the second storage unit based on the number of output lines and the number of transfer lines.   The image forming apparatus according to claim 1, wherein the instruction unit causes the output request unit to request image data of a predetermined number of lines when the number of transfer lines is larger than the number of output lines.   3. The image forming apparatus according to claim 2, wherein the predetermined number of lines is all image data currently stored in the second storage unit.   When all the image data stored in the first storage unit is stored in the second storage unit, the instruction unit 8 determines the second storage unit based on the number of output lines and the number of transfer lines. The image forming apparatus according to claim 1, wherein the output unit is not required to request image data stored in the image data.

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