JP4384055B2 - Image forming apparatus and image data output method - Google Patents

Description

  The present invention relates to an image forming apparatus and an image data output method, and more particularly, to an image forming apparatus and an image data output method for printing a document having a long size and an irregular size.

  In recent years, image forming apparatuses corresponding to image data exceeding the number of effective recording lines (number of sub-scanning lines) determined for each recording paper size, that is, so-called long-size image data, have been put into practical use.

  When an image is printed out in the image forming apparatus, first, image data to be printed out must be read, and the image data must be developed on an image memory.

  Usually, the capacity of the image memory is not so large. Therefore, the image memory can cope with long image data slightly larger than the standard size, but the image memory cannot cope with long image data in units of several tens of meters. Cannot fit within the capacity of

  With respect to this point, a method of dealing with long image data by using a memory with a large capacity as the image memory can be considered. However, this is disadvantageous in terms of cost because the memory capacity must be increased.

  Therefore, in recent years, it has been considered how to realize an image forming apparatus corresponding to long image data.

  In Patent Document 1, a long image read by a scanner device is developed on a page memory, and the long image is divided into regions each having a standard size (for example, A4) and stored using an optical disk device. An image information processing apparatus that prints a long image by reading the long image from the optical disc has been proposed.

Further, Japanese Patent Application Laid-Open No. 2004-133830 proposes a technique for dividing image data in units of bands and printing based on these units. Specifically, the image data to be printed out is developed on the band memory in band units, and then the image is output. The transferred print data for each band is stored in the hard disk, and multiple copies of the same print data are stored. An image printing system has been proposed in which print data stored in a hard disk is developed in a band memory for every printing.
JP 7-306931 A JP-A-8-123633

  However, the above technique has the following problems.

  In the technique described in Patent Document 1, when printing a long image, it is necessary to connect to the optical disk for each divided area, so that output performance at the time of printing a long image is lowered.

  In the invention described in Patent Document 2, image data (print data) to be redrawn is stored in the hard disk. However, this requires access to the hard disk at the time of redrawing, which hinders achievement of high speed redrawing. End up.

  The present invention has been made in view of the above problems, and can form a long image without using a large-capacity memory, and the performance at the time of printing a long image is not reduced. An object is to provide an image forming apparatus and an image data output method.

According to the first aspect of the present invention, determination means for determining whether or not there is a predetermined amount or more of free space in the first storage means at the time of open band request processing, and image data in band units in the first storage means A storage area securing unit that secures a storage area for one band divided into two, a band dividing unit that divides the image data into band units and develops the image data on a first storage unit, and a management unit that manages the band And drawing means for drawing for each band developed on the first storage means by the band dividing means; and a predetermined number of closed in the bands developed on the first storage means judgment means for completing the band to determine whether there, moving means for moving the divided image data of the band completed the drawing in the second storage means, of the divided image data by said moving means And a releasing means for releasing the memory of the band movement is made, the image forming for outputting of the image data by drawing the image data and expand the band units on the first storage unit When the determination means determines that there is a predetermined amount or more of free space, the storage area securing means secures a storage area for one band in the free space, and the band dividing means When one band of image data is expanded on the storage area and the determination unit determines that there is no more space than a predetermined amount, the determination unit includes the first storage unit. In the case where it is determined whether or not there is a prescribed number of closed completion bands among the bands developed in the above, with reference to the management means, and when it is determined by the judging means that a prescribed number of closed completion bands exist , The moving means is an image forming apparatus characterized by moving in said second storage means collectively divided image data of the closing completion band of the prescribed number of minutes.

According to a second aspect of the present invention, in the first aspect of the present invention, the moving unit does not move the band for performing redrawing to the second storage unit .

According to a third aspect of the present invention, in the first or second aspect of the present invention, the image forming apparatus further includes a determination unit that determines the size of the image data, and the size of the image data is equal to or larger than a predetermined size. In this case, the image data is output in units of bands using the band dividing unit, the band managing unit, the drawing unit, the moving unit, and the releasing unit, and the image data is output. When the data size is less than the prescribed size, the image data is output without being divided into the band units .

According to a fourth aspect of the present invention, the image forming apparatus according to any one of the first to third aspects further includes a detecting unit that detects a free capacity of the first storage unit, When the free capacity of the first storage means is less than a predetermined amount, the band dividing means, the band management means, the drawing means, the moving means, and the releasing means are used to The image data is output in units, and the image data is output without being divided into band units when the free capacity of the first storage means is a predetermined amount or more. .

According to a fifth aspect of the present invention, there is a step of determining whether or not there is a predetermined amount or more of free space in the first storage means by the determining means at the time of open band request processing, and a free space in the first storage means by the storage area securing means. A step of securing a storage area for one band obtained by dividing image data into bands in a portion; a step of dividing the image data into bands by a band dividing unit; and developing the image data on a first storage unit; and a drawing unit A step of performing drawing for each of the bands developed on the first storage means by the band dividing means, and a predetermined number of bands in the bands developed on the first storage means by the judging means. A step of determining whether a close completion band exists, a step of moving the divided image data of the band that has been drawn by the moving unit to a second storage unit, and a releasing unit And releasing the memory of the band in which the divided image data has been moved by the moving means, and developing and drawing the image data in band units on the first storage means. In the image data output method for outputting the image data, when the determination unit determines that a predetermined amount or more of free space exists, the storage area securing unit stores one band for the free space. A storage area is secured, and the band dividing unit expands data for one band of the image data on the storage area, and when the determination unit determines that there is no free space of a predetermined amount or more, The determining means determines whether there is a prescribed number of closed completion bands among the bands developed in the first storage means with reference to a management means that manages the bands, and When it is determined by the disconnecting means that a prescribed number of closed completion bands exist, the moving means collectively moves the divided image data of the prescribed number of closed completion bands to the second storage means. Is a method for outputting image data .

According to the present invention, when the image data is expanded on the image memory that is the first storage unit, the image data of the band that has been drawn on the image memory is moved to the HDD that is the second storage unit, there lines the opening of the present are the storage area of the band, by deploying the bands on the open image memory 66, is to deploy the elongated image data on the image memory is limited recording area It becomes possible. Accordingly, it is possible to provide an image forming apparatus that can form a long image without using a large-capacity memory and that does not deteriorate the performance during the long image printing process.

  The configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG.

  The image forming apparatus includes an ADF (automatic document feeder) 1, a document table 2, a sheet feed roller 3, a feed belt 4, a delivery roller 5, a contact glass 6, a document set detection unit 7, 1 tray 8, 2nd tray 9, 3rd tray 10, 1st paper feed unit 11, 2nd paper feed unit 12, 3rd paper feed unit 13, vertical transport unit 14, photoconductor 15 The conveyor belt 16, the fixing unit 17, the paper discharge unit 18, the developing unit 27, the exposure lamp 51, the first mirror 52, the lens 53, the CCD image sensor 54, the second mirror 55, and the third mirror 56. A reading unit 50 configured, a writing unit 57 including a laser output unit 58, an imaging lens 59, and a mirror 60, a switching plate 101, a normal paper discharge roller 102, and a transport roller 1 3, 105, a normal discharge tray 104, a stapler 106, a discharge roller 107, a staple table 108, a jogger 109, a staple completion discharge tray 110, a duplex feeding unit 111, and a branching claw 112. Is composed of.

  Next, an image forming processing operation in the image forming apparatus of the present embodiment will be described.

  A bundle of documents placed on the document table 2 of the ADF 1 with the image surface of the document facing up is pressed from the top document to the feed roller 3 by feeding the start key on the operation unit. It is fed to a predetermined position on the contact glass 6 by the feeding belt 4.

  The document fed to a predetermined position on the contact glass 6 is read by the reading unit 50, and the document that has been read is discharged via the feeding belt 4 and the discharge roller 5. Further, when the document set detection unit 7 detects that there is a next document on the document table 2, it is fed onto the contact glass 6 in the same manner as the processing operation described above. The feeding roller 3, the feeding belt 4, and the discharging roller 5 are driven by a conveyance motor.

  The recording sheets stacked on the first tray 8, the second tray 9, and the third tray 10 are fed by the first paper feeding device 11, the second paper feeding device 12, and the third paper feeding device 13, respectively, and are conveyed longitudinally. The unit 14 is transported to a position where it abuts on the photoreceptor 15.

  The image data read by the reading unit 50 is written on the photoconductor 15 by the laser from the writing unit 57, and an electrostatic latent image is formed on the photoconductor 15. The electrostatic latent image is developed by passing through the developing unit 27, and a toner image is formed on the photoreceptor 15.

  The recording paper transported from the vertical transport unit 14 is transported by a transport belt 16 having the same speed as the rotation speed of the photoconductor 15, and at this time, the toner image formed on the photoconductor 15 is transferred onto the recording paper. . It is conveyed to the fixing unit 17.

  The recording sheet on which the toner image is transferred is conveyed to the fixing unit 17. In the fixing unit 17, the toner image transferred onto the recording paper is thermally fixed.

  The photoconductor 15, the transport belt 16, the fixing unit 17, the paper discharge unit 18, and the developing unit 27 are driven by a main motor 25 shown in FIG. Each of the paper feeding devices 11 to 13 is driven by transmitting the driving of the main motor 25 shown in FIG. The vertical conveyance unit 14 is driven by the intermediate clutch 21 transmitting the drive of the main motor 25.

  The paper discharge unit 18 discharges the recording paper to the finisher 100 that is a post-processing device.

  The finisher 100 is a device for guiding the recording paper to the normal paper discharge tray 104 side and the staple table 108 side. When the switching plate 101 is switched upward, the recording paper is discharged to the normal paper discharge tray 104 side via the conveyance roller 103. Conversely, when the switching plate 101 is switched downward, the recording paper is conveyed to the staple table 108 via the conveyance roller 105 and the paper discharge roller 107.

  The normal paper discharge tray 104 is a paper discharge tray that can be moved back and forth, and sorts the recording paper (copy paper) that moves forward and backward and is simply discharged. As a result, the recording paper conveyed to the normal paper discharge tray 104 is sorted for each original or each copy unit sorted by the image memory.

  On the other hand, each time a sheet of recording paper loaded on the staple table 108 is discharged, the paper end face is aligned by the paper alignment jogger 109, and is bound by the stapler 106 upon completion of a partial copy. The group of recording sheets bound by the stapler 106 is stored in the staple completion discharge tray 110 by its own weight.

  When images are formed on both sides of the recording paper, the branching claw 112 for switching the path is set on the upper side. When the branching claw 112 is set on the upper side, the recording paper on which an image is formed on one side of the recording paper is temporarily stored in the double-sided paper feeding unit 111 without being conveyed to the paper discharge tray 104 side. Then, the recording paper once stocked in the duplex feeding unit 111 is fed again, and the toner image formed on the photosensitive member 15 is transferred again. After the double-sided transfer, the branching claw 112 for switching the path is set on the lower side, and the recording paper subjected to the double-sided printing is guided to the finisher 100. In this way, images are formed on both sides of the recording paper.

  In the above description, the standard size recording paper is described as the printing paper. However, the printing paper is not limited to the standard size recording paper, and may be roll paper.

  Next, operations from the original reading process to the writing process in the image forming apparatus of the present embodiment will be described.

  The reading unit 50 includes a contact glass 6 on which a document is placed and an optical scanning system. The optical scanning system includes an exposure lamp 51, a first mirror 52, a lens 53, and a CCD image sensor 54. The exposure lamp 51 and the first mirror 52 are fixed on the first carriage, and the second mirror 55 and the third mirror 56 are fixed on the second carriage.

  When reading a document image, the first carriage and the second carriage are mechanically scanned at a relative speed of 2: 1 so that the optical path length does not change. This optical scanning system is driven by a scanner drive motor. The document image is read by the CCD image sensor 54, converted into an electrical signal, and processed.

  The image magnification is changed by moving the lens 53 and the CCD image sensor 54 in the left-right direction in FIG. In other words, the left and right positions of the lens 53 and the CCD image sensor 54 are set corresponding to the designated magnification.

  The writing unit 57 includes a laser output unit 58, an imaging lens 59, and a mirror 60. Inside the laser output unit 58, there are mounted a laser diode as a laser light source and a rotating polygon mirror (polygon mirror) that is rotated at a constant high speed by a motor.

  Laser light emitted from the laser output unit 58 is polarized by the polygon mirror, passes through the imaging lens 59, is folded by the mirror 60, and is focused on the surface of the photoconductor 15.

  The laser beam is exposed and scanned in the direction (main scanning direction) perpendicular to the direction in which the photoconductor 15 rotates, and recording is performed in units of lines output by the selector of the image processing unit. An electrostatic latent image is formed on the photoconductor 15 by repeating writing in the main scanning direction at a predetermined cycle corresponding to the rotational speed and recording density of the photoconductor 15.

  A beam sensor that generates a main scanning synchronization signal is disposed at a position where a laser beam near one end of the photoconductor 15 is irradiated. Based on the main scanning synchronization signal, control of image recording start timing in the main scanning direction and generation of a control signal for inputting / outputting the image signal are performed.

  Next, the control system of the image forming apparatus shown in FIG. 1 will be described with reference to FIG.

  As shown in FIG. 2, the control system of the image forming apparatus has each distributed control device arranged around a main controller 20 that controls the entire image forming apparatus. The main controller 20 is connected to the IPU via a system bus. (Image processing unit) 49, ADF 1, and operation unit 30 are connected.

  The operation unit 30 performs display for the operator and function setting from the operator. Further, the IPU 49 performs control of the scanner, control of writing a document image into the image memory of the IPU 49, and image formation processing from the image memory.

  A main motor 25, an intermediate clutch 21, a first paper feed clutch 22, a second paper feed clutch 23, and a third paper feed clutch 24 are connected to the main controller 20. The ADF 1 is connected to the transport motor 26 and the document set detection unit 7. A liquid crystal display and various input keys are connected to the operation unit 30.

  Next, the configuration of the image processing unit (IPU) 49 in the image forming apparatus of this embodiment will be described with reference to FIG. FIG. 3 shows the internal configuration of the IPU 49.

  The IPU 49 receives the reflected light of the light emitted from the exposure lamp 51 of FIG. 1 by the CCD image sensor 54 and performs photoelectric conversion. The A / D converter 61 converts the analog image data obtained by photoelectric conversion into digital image data. The shading correction unit 62 performs shading correction on the digital image data converted by the A / D converter 61. The MTF correction unit / γ correction unit 63 performs MTF correction, γ correction, and the like on the image data subjected to the shading correction.

  The scaling processing unit 72 performs scaling processing on the image data, enlarges / reduces the image data according to the scaling ratio, and outputs it to the selector 64. The selector 64 selects the output γ correction unit 71 or the image memory controller 65 as an output destination, and outputs the image data. The writing γ correction unit 71 performs γ correction on the image data and outputs the image data to the writing unit 57.

  The image memory controller 65 and the selector 64 are configured to be able to input and output image signals in both directions.

  In addition to the image data input from the reading unit 50, the IPU 49 also receives image data (for example, data output from a data processing device such as a personal computer) supplied from the outside via the I / O port 67. It has a function capable of selectively executing input / output of a plurality of data so that it can be processed.

  The IPU 49 includes a CPU 68 for setting the image memory controller 65 and controlling the reading unit 50 and the writing unit 57 in FIG. 1, and a ROM 69 and a RAM 70 for storing programs and data controlled by the CPU 68.

  The CPU 68 performs data write processing and data read processing of the image memory 66 via the image memory controller 65. The image data sent to the image memory controller 65 is compressed in the image memory controller 65 and sent to the image memory 66.

  The image data stored in the image memory 66 can be accessed from the CPU 68. As a result, the image data stored in the image memory 66 can be processed. For example, it is possible to perform thinning processing of image data, clipping processing of image data, and the like.

  Next, the image memory controller 65, the image memory 66, and the HDD 75 will be described.

  As the image memory 66, a memory capable of high-speed access is used. This is so that the data can be written substantially in synchronization with the transfer speed of the input image data at the time of image input, or the output image data can be read at a high speed at the time of image output. .

  The image memory 66 is divided into a plurality of areas according to the size of the image data to be processed, and the image data can be input / output simultaneously. Also, in order to be able to execute input and output of image data in each divided area in parallel, two sets of address and data lines for reading and writing are used for the interface with the image memory controller 65. It is done. Thus, an operation of outputting (reading) an image by area 2 while inputting (writing) image data to area 1 is possible.

  The HDD 75 is a large-capacity memory that stores data for combining and sorting input images. By providing the HDD 75, an external power source is unnecessary and an image can be retained permanently. When reading and holding a plurality of standard documents (format documents) with a scanner, the HDD 75 is generally used.

  Next, an outline of the operation of the memory controller 65 when inputting / outputting image data to / from the image memory 66 will be described.

  When inputting image data to the image memory 66, first, image data to be written to the image memory 66 is selected from a plurality of data in the input data selector. Here, the image data selected by the input data selector is supplied to the image composition unit and synthesized with the data already stored in the image memory 66.

  The image data processed by the image composition unit is compressed by the primary compression / decompression unit, and the compressed image data is written into the image memory 66. The image data written in the image memory 66 is further compressed by the secondary compression / decompression unit as necessary and stored in the HDD 75.

  When the image data is output from the image memory 66, if the image is expanded in the image memory 66, the image data on the image memory 66 is expanded in the primary compression / decompression unit, and the expanded data Alternatively, the data after the image composition of the decompressed data and the input data is selected by the output data selector and output.

  On the other hand, when the image to be output is not expanded on the image memory 66, the output target image data stored in the HDD 75 is expanded by the secondary compression / decompression unit. Then, the decompressed data is expanded on the image memory 66 and then an image output operation is performed.

  Next, with reference to FIG. 4, processing when printing a long size image according to the present embodiment will be described. FIG. 4 shows the exchange between the printer application, the image memory controller 65, and the image memory 66 when printing a long size image.

  First, when the execution start key for printing a long document is pressed, the printer application of the image forming apparatus makes an open page request to the image memory controller 65 in order to secure a storage area. The “page” used here is a unit representing one image data.

  If the open page of the image memory 66 by the image memory controller 65 is successful, the printer application makes an open band request to the image memory controller 65. A “band” is a unit representing one of the image data as shown in FIG. 5 divided into strips.

  In this embodiment, the image memory controller 65 secures a storage area on the image memory 66, decomposes the input long image data into band units, assigns a different identification ID to each decomposed band, and Management of identification ID is performed. Here, a storage area for managing the identification ID is provided in the image memory 66. Note that a RAM may be provided outside the image memory controller 65, and the RAM may be used as a storage area for managing identification IDs.

  When the open band of the image memory 66 is successful, that is, when the storage area for one band is successfully secured on the image memory 66, the image memory controller 65 stores the image data for one band of the long image on the storage area. expand.

  When the development of image data for one band is completed and drawing for the image data of the band is completed, the printer application issues a close band request for the band. A flow at the time of the close band request processing is shown in FIG. When a close band request is made (S201), the band is registered as a close completion band (S202).

  Note that information management for each band, such as closing completion band registration at the time of the above processing, is performed by a storage area provided in the image memory 66 or a RAM provided outside the image memory controller 65.

  The above open band / close band processing is executed until the output for the number of divided bands, that is, one page of the long image is completed.

  Note that the storage area of the image memory 66 cannot secure a storage area for one page of a long image. Therefore, in the image forming apparatus of the present embodiment, the close completion band is moved to the HDD 75 at any time during the open band request processing, and the storage area of the image memory 66 reserved by the band is released. Then, the band-unit image data is successively developed in an empty memory formed by releasing the storage area of the band.

  FIG. 7 shows a flow at the time of open band request processing. When an open band request is made by the printer application, whether or not there is a predetermined amount or more of free memory in the image memory 66, in other words, whether or not there is a free storage area in which image data for one band can be expanded. Is checked by the image memory controller 65 (S211). If there is a predetermined amount or more of free memory (S211 / Yes), a storage area for one band is secured in this free memory (S217), and image data for one band of the long image is stored in the storage area. The image is expanded upward (S218).

  On the other hand, if there is no free memory of a predetermined amount or more in the image memory 66 (S211 / No), it is determined whether or not there is a close completion band among the bands developed on the image memory 66. (S212).

  An example of a management table for managing information of each band is shown in FIG. If “1” is written in the “C band state” field, it is a closed band, and if “0” is written, it is a closed band.

  If the close completion band does not exist (S212 / No), it is determined that the storage area on the image memory 66 is full, and the process exits without executing the open band process (S213).

  When the close completion band exists (S212 / Yes), the image data of the close completion band is moved to the HDD 75 (S214). Then, the close registration of the band is deleted (S215). That is, in FIG. 8, the “C band state” is rewritten from “1” to “0”. Then, the processing for releasing the memory area occupied by the band is executed (S216). When the release process is performed, the information management table is also released.

  Next, a storage area for one band is newly secured in the released area (S217), and image data for one band of the long image is developed on the storage area (S218).

  The open band / close band processing is executed for the number of bands of the long image, and when the output of the entire long image is completed, the image forming process for one page is completed. When the image forming process is completed, the printer application makes a close page request. FIG. 9 shows a processing flow when the close page request is executed.

  When a close page request is made, first, the image memory controller 65 moves the image data of the close completion band to the HDD 75 (S221). Then, the registration of the closed band of the band is deleted (S222). After deregistering the closed band, the area on the image memory 66 reserved by the band is released (S223).

  This process is executed for all bands on the image memory 66 (S224), and when the release process is completed for all the storage areas on the image memory 66 (S224 / Yes), the process is performed assuming that the close page process is completed. Exit (S225).

  According to this embodiment, when an image is developed on the image memory, the image data of the band that has been drawn on the image memory is moved to the HDD 75, and the storage area in which the band exists is sequentially released and released. By sequentially expanding the bands on the image memory 66, the long image data is expanded on the image memory which is a limited recording area. Accordingly, it is possible to provide an image forming apparatus that can form a long image without using a large-capacity memory and that does not deteriorate the performance during the long image printing process.

  In the image forming apparatus of the present embodiment, when the open band is executed, the image data of the close completion band is moved to the HDD 75 (S214). If the image data is moved for each band, the access frequency to the HDD 75 is increased and the performance speed is increased. It will decline. Therefore, when the close completion band reaches a specified number, the HDD 75 may be moved together. Specifically, the status of the “C band state” in the management table of FIG. 8 is checked, and when the number of bands with the C band state “1” reaches a specified number, the bands are moved together to the HDD 75. Let By controlling in this way, the access frequency to the HDD 75 can be suppressed, and a decrease in performance speed can be suppressed.

  In the image forming apparatus of the present embodiment, redrawing may be executed for image data. Redrawing refers to image data overwriting and writing operations. However, when such redrawing processing is performed on the HDD 75, performance is degraded. Therefore, in the above-described embodiment, the band that has been redrawn before the close completion band reaches the specified number may be removed from the target to be moved to the HDD 75. Specifically, the redraw target band is managed in the management table of FIG. 8, the redraw target band is held on the image memory 66 without being moved to the HDD 75, and the redraw process is performed on the image memory 66. Do. By controlling in this way, it is possible to perform the redrawing process without degrading the performance.

  Further, in the image forming apparatus of the present embodiment, it may be controlled to execute the band division printing process when printing a page of a specified size or larger. By controlling in this way, the band division printing process is not executed when printing a page smaller than the specified size, and the band division printing process is executed when printing a page larger than the specified size. It is possible to select an efficient printing method according to the situation.

  Further, in the image forming apparatus of the present embodiment, the band division printing process may be controlled to be executed when the free space of the image memory 66 becomes less than a predetermined amount. Specifically, the free space of the image memory 66 is checked using the management table of FIG. 8, and the band division printing process is executed when the free space is less than a predetermined amount. By controlling in this way, an efficient printing method can be selected according to the free space of the image memory 66.

1 is a diagram illustrating a configuration of an image forming apparatus. 2 is a diagram illustrating a configuration of a control system of the image forming apparatus. FIG. 1 is a block diagram illustrating a configuration of an image processing unit (IPU) in an image forming apparatus. It is a figure which shows the exchange between the printer application at the time of printing a long size image, and an image memory. It is a figure for demonstrating the image data for 1 page. It is a figure which shows the flow at the time of a close band request | requirement process. It is a figure which shows the flow at the time of an open band request process. It is a figure which shows the management table which performs the information management of each band. It is a figure which shows the processing flow at the time of close page request | requirement execution.

Explanation of symbols

65 Image memory controller 66 Image memory 75 HDD

Claims (5)

Determination means for determining whether or not there is a predetermined amount or more of free space in the first storage means during open band request processing;
Storage area securing means for securing a storage area for one band obtained by dividing image data into bands in an empty portion of the first storage means;
A band dividing unit that divides the image data into band units and develops the image data on a first storage unit;
Management means for managing the band;
Drawing means for drawing for each of the bands developed on the first storage means by the band dividing means;
Determining means for determining whether a prescribed number of closed completion bands are present in the bands developed on the first storage means;
Moving means for moving the divided image data of the band for which the drawing has been completed to a second storage means;
Opening means for releasing the memory of the band in which the divided image data has been moved by the moving means,
An image forming apparatus for outputting the image data by drawing the image data and expand the band units on said first storage means,
When it is determined by the determining means that there is a predetermined amount or more of free space, the storage area securing means secures a storage area for one band in the free space, and the band dividing means Expand one band of data on the storage area,
If it is determined by the determination means that there is no free space of a predetermined amount or more, the determination means determines whether there is a prescribed number of closed completion bands among the bands developed in the first storage means. With reference to the management means,
When it is determined by the determination means that a prescribed number of closed completion bands exist, the moving means collectively moves the divided image data of the prescribed number of closed completion bands to the second storage means. An image forming apparatus.   The image forming apparatus according to claim 1, wherein the moving unit does not move the band to be redrawn to the second storage unit.   The image forming apparatus further includes a determination unit that determines the size of the image data,
  If the size of the image data is greater than or equal to the specified size,
  Using the band dividing unit, the band managing unit, the drawing unit, the moving unit, and the opening unit, the image data is output by the band unit,
  When the size of the image data is less than the prescribed size,
  The image forming apparatus according to claim 1, wherein the image data is output without being divided into the band units.   The image forming apparatus further includes a detection unit that detects a free capacity of the first storage unit,
  When the free capacity of the first storage means is less than a predetermined amount,
  Using the band dividing unit, the band managing unit, the drawing unit, the moving unit, and the opening unit, the image data is output by the band unit,
  When the free capacity of the first storage means is a predetermined amount or more,
  4. The image forming apparatus according to claim 1, wherein the image data is output without being divided into the band units. 5.   A step of determining whether or not there is a predetermined amount or more free space in the first storage means by the determination means during the open band request processing;
  Securing a storage area for one band obtained by dividing image data into band units in an empty portion of the first storage means by a storage area securing means;
  Dividing the image data into band units by a band dividing unit and expanding the image data on a first storage unit;
  Drawing for each band developed on the first storage means by the band dividing means by the drawing means;
  Determining whether a prescribed number of closed completion bands are present in the bands developed on the first storage means by a determination means;
  Moving the divided image data of the band that has been drawn to the second storage unit by a moving unit;
  And releasing the memory of the band in which the divided image data has been moved by the moving means by the releasing means,
  An image data output method for outputting the image data by developing and rendering the image data in band units on the first storage means,
  If it is determined by the determining means that there is a predetermined amount or more of free space, the storage area securing means secures a storage area for one band in the free space, and the band dividing means Expand one band of data on the storage area,
  If it is determined by the determination means that there is no free space of a predetermined amount or more, the determination means determines whether there is a prescribed number of closed completion bands among the bands developed in the first storage means. Is determined with reference to management means for managing the band,
  When it is determined by the determination means that a prescribed number of closed completion bands exist, the moving means collectively moves the divided image data of the prescribed number of closed completion bands to the second storage means. A method for outputting image data.

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