JP6171779B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to a technique for reducing a memory capacity used for processing image data.

  In recent years, the amount of image data to be processed by an image forming apparatus in order to realize high-quality and high-resolution image formation has increased dramatically, and it has become necessary to mount a huge amount of memory. On the other hand, there is a high demand for cost reduction for image forming apparatuses, and particularly in emerging countries, it is necessary to overcome severe price competition. For this reason, there is a limit to increasing the memory capacity, and efficient memory management is required.

In response to such a request, for example, the following techniques have been proposed. That is, when a host computer is interposed between an image forming apparatus and a device such as a PC (Personal Computer) that issues a print job, and the host computer receives a print job from the PC, the image to be executed Check the memory capacity of the forming device.
As a result of the confirmation, if the free space of the memory is small, the host computer displays a warning screen before sending the print data to the image forming apparatus to notify the shortage of the memory capacity. In this way, a user such as a PC can select whether to continue or interrupt the execution of the print job according to the free space in the memory of the image forming apparatus.

JP 2012-242897 A

However, in the above prior art, a host computer is required in addition to the image forming apparatus, which is against the request for reducing the apparatus cost. In addition, since the shortage of the free space of the memory of the image forming apparatus is only notified, the reduction of the memory capacity causes the user's convenience to decrease as it is.
In order to deal with such problems, conventionally, in an image forming apparatus, a dedicated memory area is allocated for each program or process. However, if a memory area is shared between a printing process and a process other than printing, It is expected that further memory capacity reduction can be achieved without reducing the memory area used for the printing process.

However, if any process that shares the memory area occupies the memory area for a long time, execution of other processes is hindered, resulting in malfunction of the image forming apparatus or loss of user convenience. There is a risk that
The present invention has been made in view of the above problems, and provides an image forming apparatus capable of preventing malfunction and reducing memory capacity while ensuring user convenience. Objective.

  In order to achieve the above object, an image forming apparatus according to the present invention is an image forming apparatus having an original reading unit for reading an image from an original, and uses a first memory area for RIP for image data to be formed. A basic RIP processing unit that performs processing and a basic image conversion process that is an image conversion process that uses only a second memory area that does not overlap the first memory area for image data read by the document reading unit. For the image conversion means and the image data read by the document reading means, the extended image conversion process, which is an image conversion process that has either a higher compression rate or higher resolution than the basic image conversion process, In addition to the memory area, extended image conversion means that uses at least a part of the first memory area, and to the first memory area As access do not conflict, characterized by comprising said RIP processing means, and switching means switching between the extended image converting means.

In this way, the RIP processing means and the extended image conversion means are switched so that accesses to the first memory area do not compete with each other, so that the second memory area is switched between the RIP processing means and the extended image conversion means. Can be shared. Accordingly, it is possible to reduce the memory capacity to be mounted on the image forming apparatus.
Further, the processing of the image data read by the RIP processing or the document reading means does not require precise time control such as recording sheet conveyance control or fixing device temperature control at the time of image formation. This is preferable because the process can proceed normally even if it waits a little by switching.

  Specifically, the basic image conversion process is a process of converting image data read by the document reading unit into PDF data, and the extended image conversion process is a process of converting the image data read by the document reading unit. The basic image conversion process may be a process of converting image data read by the document reading unit into facsimile image data by G3 compression, and the extended image conversion process may be a process of converting into CPDF data. The image data read by the document reading means may be converted into facsimile image data by G4 compression.

  Further, the switching control means further switches the processing at regular intervals when either one of the RIP processing means and the extended image conversion means executes processing and the other is waiting. Also good. In this way, even when the number of pages to be processed is large, competing processes can be executed fairly. Therefore, it is possible to prevent unfairness caused by a user who has instructed one process waiting for a longer time than a user who has instructed the other process.

Also, for each of said RIP processing, the basic image transformation process and the extended image conversion process, after exceeding a predetermined time-out period during the process, including the time-out processing means for executing the time-out process, as a time-out process, the When either the RIP process or the extended image conversion process is incomplete, the switching unit waits until the page being processed is completed for the incomplete process, and is executed between the RIP process and the extended image conversion process. Switching may be performed so that the process is suspended and the other process is executed.

In this way, even when processing takes a long time, it is possible to avoid inconveniences such as program shutdown due to occurrence of timeout.
Further, the switching control means may further perform the switching depending on whether the first memory area is used for the RIP processing means or the extended image converting means. Further, the switching may be performed every time the process being executed is completed in units of pages.

Further, the switching control means further performs processing by the basic image converting means instead of the extended image converting means when the document reading means reads image data to be processed during the RIP processing. You can go. This makes it possible to avoid a delay due to access contention with the RIP process, particularly when the reading of the document is urgent.
A determination unit configured to determine a length of time required for the RIP process to wait when the document reading unit reads image data to be processed during the RIP process; The switching control unit may further perform processing by the basic image conversion unit instead of the extended image conversion unit when the determination unit determines that a long time is required.

When the RIP process does not require a long time, the delay of the extended image conversion process due to the conflict of memory access can be reduced, so that the image conversion process can be executed so as to increase the compression rate and resolution of the image data.
In this case, when processing is performed by the basic image conversion unit instead of the extended image conversion unit, a notification unit that notifies the user of the fact may be provided. This is to explain to the user the reason for reducing the compression rate and resolution of the image data.

  A receiving unit that receives an instruction from a user as to whether or not to perform processing in the basic image converting unit instead of the extended image converting unit when the determining unit determines that a long time is required; When a negative instruction is received by the means, the switching control means is prohibited from performing processing by the basic image conversion means instead of the extended image conversion means, and processing is performed by the extended image conversion means. Prohibiting means to perform may be provided.

Whether the delay of the extended image conversion process or the reduction in the compression rate or resolution of the image data is inconvenient is a problem for the user and is given priority to the convenience of the user.
Incidentally, the determining means, among the pages according to the prior Symbol R IP processing, depending on whether the processing time of the page RIP process is completed is longer than a predetermined time, may determine the length of processing time, of the pages according to the prior Symbol R IP processing, the total time of the processing time of the page RIP process is complete depending on whether it is a predetermined time or more may be determined length of processing time. In this way, it is possible to easily estimate whether the RIP process takes a long time.

1 shows a configuration of an image forming apparatus according to the present embodiment. 3 is a block diagram illustrating a main hardware configuration of a control unit 112. FIG. It is a figure which shows the structure of the software which shares a memory area. 6 is a flowchart illustrating an operation when a control unit 112 receives a job. 4 is a flowchart illustrating a timeout process of a control unit 112. It is a flowchart which shows the operation | movement at the time of the job reception which concerns on the modification of this invention. It is a figure which illustrates the notification screen which concerns on the modification of this invention. It is a flowchart which shows the operation | movement at the time of the job reception which concerns on the modification of this invention. It is a figure which illustrates the confirmation screen which concerns on the modification of this invention. It is a flowchart which shows the operation | movement at the time of the job reception which concerns on the modification of this invention. It is a figure which shows the structure of the software which shares the memory area | region which concerns on the modification of this invention. It is a flowchart which shows the process by the switching control program 300 which concerns on the modification of this invention.

Embodiments of an image forming apparatus according to the present invention will be described below with reference to the drawings.
The image forming apparatus according to the present embodiment includes an original reading unit and an image forming unit, and raster format image data (hereinafter referred to as “raster image data”) read by the original reading unit is PDF (hereinafter referred to as “raster image data”). PDF conversion processing for conversion to data in portable document format (hereinafter referred to as “PDF data”) and data in CPDF (Compact PDF) format (hereinafter referred to as “CPDF data”) having a higher compression rate than the PDF format. ) To perform CPDF conversion processing.

When a print job is received from another device such as a PC (Personal Computer), a RIP (RIP) that generates raster image data from print data described in PDL (Page Description Language) (hereinafter referred to as “PDL data”). Raster Image Processing) processing is executed.
In general, among processes executed by the image forming apparatus, processes that require high responsiveness, such as communication processing and user interface drawing processing, are sufficiently responsive if they share a memory area with other processes. May not be able to be secured. On the other hand, since RIP processing and CPDF conversion processing are not required to be responsive, a memory area can be shared by these processing.

Based on such knowledge, in this embodiment, the memory area is shared by the PDF conversion process, the CPDF conversion process, and the RIP process, thereby reducing the memory capacity while ensuring user convenience.
[1] Configuration of Image Forming Apparatus First, the configuration of the image forming apparatus according to the present embodiment will be described.

  FIG. 1 is a diagram illustrating a main configuration of the image forming apparatus according to the present embodiment. As shown in FIG. 1, the image forming apparatus 1 is a so-called tandem type multi-function peripheral (MFP), and includes a document reading unit 100, an image forming unit 110, and a paper feeding unit 130. Yes. The document reading unit 100 optically reads a document placed on the document table tray 101 and conveys it by an automatic document feeder (ADF) 102 to generate image data. The image data is stored in the control unit 112 described later.

  The image forming unit 110 includes image forming units 111Y to 111K, a control unit 112, an intermediate transfer belt 113, a secondary transfer roller pair 114, a fixing device 115, a paper discharge roller pair 116, a paper discharge tray 117, a cleaning blade 118, and a timing roller pair. 119. The image forming unit 110 is equipped with toner cartridges 120Y to 120K that supply toners of Y (yellow), M (magenta), C (cyan), and K (black) colors.

  The image forming units 111Y to 111K receive toner supply from the toner cartridges 120Y to 120K, respectively, and form toner images of each color of YMCK under the control of the control unit 112. For example, the image forming unit 111Y includes a photosensitive drum 121, a charging device 122, an exposure device 123, a developing device 124, and a cleaning device 125. Under the control of the control unit 112, the charging device 122 uniformly charges the outer peripheral surface of the photosensitive drum 121. The exposure device 123 image-exposes the outer peripheral surface of the photosensitive drum 121 according to the image data to form an electrostatic latent image.

  The developing device 124 supplies toner to the outer peripheral surface of the photoconductive drum 121 to develop (visualize) the electrostatic latent image. A primary transfer voltage is applied to the primary transfer roller 126, and the toner image on the outer peripheral surface of the photosensitive drum 121 is electrostatically transferred (primary transfer) to the intermediate transfer belt 113 by electrostatic adsorption. Thereafter, the cleaning device 125 scrapes off the toner remaining on the outer peripheral surface of the photosensitive drum 121 with a cleaning blade, and further, the charge is removed by illuminating the outer peripheral surface of the photosensitive drum 121 with a static elimination lamp.

Similarly, the image forming units 111M to 111K also form toner images of each color of MCK. These toner images are sequentially primary transferred onto the intermediate transfer belt 113 so as to overlap each other. The intermediate transfer belt 113 is an endless rotator, and rotates in the direction of arrow A to convey the primary transferred toner image to the secondary transfer roller pair 114.
Each of the paper feeding units 130 includes a paper feeding cassette 131 that stores the recording sheets S for each sheet size, and supplies the recording sheets S to the image forming unit 110. The supplied recording sheet S is unloaded one by one in parallel with the intermediate transfer belt 113 conveying the toner image, and is conveyed to the secondary transfer roller pair 114 via the timing roller pair 119. The timing roller pair 119 includes a pair of rollers, and conveys the recording sheet S in accordance with the timing at which the toner image reaches the secondary transfer roller pair 114.

  The secondary transfer roller pair 114 includes a pair of rollers to which a secondary transfer voltage is applied and has a potential difference, and the roller pairs are pressed against each other to form a transfer nip portion. The toner image on the intermediate transfer belt 113 is electrostatically transferred (secondary transfer) onto the recording sheet S at the transfer nip portion. The recording sheet S to which the toner image is transferred is conveyed to the fixing device 115. Further, after the secondary transfer, the residual toner remaining on the intermediate transfer belt 113 is further conveyed in the direction of arrow A, then scraped off by the cleaning blade 118 and discarded.

The fixing device 115 heats and melts the toner image and presses the toner image on the recording sheet S. The recording sheet S to which the toner image has been fused is discharged onto the discharge tray 117 by the discharge roller pair 116.
The control unit 112 controls the operation of the image forming apparatus 1 including the above-described operation panel (not shown). The control unit 112 also transmits / receives image data to / from other devices such as a personal computer (PC) and receives a print job. The control unit 112 includes a facsimile modem and transmits / receives image data to / from other facsimile apparatuses via a facsimile line.

In addition to the above, when transferring the toner image, a transfer charger or a transfer belt may be used instead of the transfer roller. Further, when the residual toner on the intermediate transfer belt 113 is removed, a cleaning brush or a cleaning roller may be used instead of the cleaning blade 118.
[2] Hardware Configuration of Control Unit 112 Next, the hardware configuration of the control unit 112 will be described.

FIG. 2 is a block diagram illustrating a main hardware configuration of the control unit 112. As shown in FIG. 2, a CPU (Central Processing Unit) 200, a nonvolatile memory 201, a RAM (Random Access Memory) 202, an HDD (Hard Disk Drive) 203, a timer 204, a NIC (Network Interface Card) 205, and a FAX modem 206.
When the image forming apparatus 1 is powered on, the CPU 200 reads and starts a boot program from a non-volatile memory (for example, ROM (Read Only Memory)) 201, and the control read from the HDD 203 using the RAM 202 as a working storage area. Run the program. Further, the CPU 200 sets a timeout time in the timer 204, and executes a timeout process by accepting an interrupt from the timer 204 after the timeout time has elapsed.

The NIC 205 executes protocol processing for communicating with other apparatuses via the LAN, and the FAX modem 206 transmits and receives data to and from other facsimile apparatuses via the facsimile line. The CPU 200 controls the document reading unit 100, the image forming units 111Y to 111K, the paper feeding unit 130, and the like.
In addition, the CPU 200 is connected to the operation panel 210, and receives an instruction input from the user through the operation unit 211 provided in the operation panel 210, and displays information for the user through the display unit 212. In the present embodiment, a liquid crystal display panel is used as the display unit 212, and a touch panel and hard keys that are arranged on the liquid crystal display panel are used as the operation unit 211.

[3] Software Configuration of Control Unit 112 Next, the software configuration of the control unit 112 will be described.
FIG. 3 is a diagram illustrating a configuration of software that shares a memory area. As illustrated in FIG. 3, the control unit 112 executes a switching control program 300, a RIP processing program 301, an extended image conversion program 302, and a basic image conversion program 303.

The RIP processing program 301 sequentially generates raster image data in units of pages from PDL data related to a print job using an extended image conversion area / RIP processing area (hereinafter simply referred to as “shared area”) 310 as a working storage area. RIP processing is executed.
On the other hand, the basic image conversion program 303 converts the raster image data output from the document reading unit 100 into PDF data in units of pages using the basic image conversion area 311 as a working storage area. At the time of this conversion, the PDF conversion program 301 performs JPEG (Joint Photographic Experts Group) compression in order to reduce the file size of the PDF data. JPEG is standardized in, for example, Japanese Industrial Standard (JIS X 4301).

  The extended image conversion program 302 converts raster image data output from the document reading unit 100 into CPDF data in units of pages. In this conversion, the extended image conversion program 302 detects the character data portion and the photo data portion of the raster image data, binarizes the character color of the character data portion, and then performs G4 compression. On the other hand, JPEG compression is applied to the photo data portion.

G4 compression is a so-called MMR (Modified Modified READ (Relative Element Address Designate)) encoding method, 6 (Facsimile coding schemes and coding control function for group 4 facsimile apparatus).
The extended image conversion program 302 performs JPEG compression using the basic image conversion area 311 as a work storage area, and uses the shared area 310 as a work storage area for G4 compression.

The switching control program 300 causes the RIP processing program 301 and the extended image conversion program 302 to operate alternatively. Thus, overwriting of data between the RIP processing program 301 and the extended image conversion program 302 is avoided, and the shared area 310 is shared.
[4] Operation of Switching Control Program 300 Next, the operation of the switching control program 300 will be described.

(1) Operation at the time of job reception First, the operation at the time of job reception will be described.
FIG. 4 is a flowchart showing the operation of the control unit 112 when accepting a job. As shown in FIG. 4, when the control unit 112 receives a new job, the switching control program 300 confirms the type of the job. If the job is not a print job (S401: NO) and is a scan job (S402: YES), it is confirmed whether the RIP processing program 301 is being executed.

  This is because if the extended image conversion program 302 is executed while the RIP processing program 310 is being executed, data may be overwritten in the shared area 310 and the processing may become abnormal. As a result of the confirmation, if the RIP process is being executed (S403: YES), it is confirmed which of the RIP processing program 301 and the extended image conversion program 302 has priority. In the case of performing this confirmation, for example, the following may be performed.

  Since the processing time required for converting raster image data into CPDF data varies depending on the original, the extended image conversion program 302 waits for conversion when the processing speed falls below the reading speed of the image reading unit 100. The processing is not in time, and white spots occur in the CPDF data. For this reason, the extended image conversion program 302 may always be prioritized over the RIP processing program 301.

  Further, since the extended image conversion program 302 uses the common area 310 when the raster image data has a character data portion, the extended image conversion program 302 is changed to the RIP processing program when the raster image data has a character data portion. If the raster image data has no character data portion, the RIP processing program 301 may be prioritized.

In this way, it is possible to execute a print job early while preventing white spots in CPDF data.
When priority is given to the extended image conversion program 302 (S404: YES), the RIP processing program 301 currently being executed waits for the page being processed to be completed, and when it is completed (S405: YES), the switching control program 300 suspends execution of the RIP processing program 301 (S406). The extended image conversion program is activated (S407). By doing so, contention for writing to the shared area 310 can be prevented.

When the RIP processing program 301 has a page to be subjected to RIP processing each time RIP processing is completed in units of pages, in other words, when it is a page other than the last page, the switching control program 300 notifies the switching control program 300 of the page. After the notification, the RIP processing program 301 may be continued after waiting for an instruction from the switching control program 300.
If priority is not given to the extended image conversion program 302 (S404: YES), the execution of the extended image conversion program 302 is suspended (S408), and the execution of the RIP processing program 301 is continued (S409).

If the RIP processing program 301 is not being executed (S403: NO), there is no possibility of memory access conflict, so the switching control program 300 immediately starts the extended image conversion program 302 (S407).
When the new job is a print job (S401: YES), the switching control program 300 confirms whether or not the extended image conversion program 302 is being executed. If it is being executed (S410: YES), the program to be preferentially executed is confirmed. When priority is given to the RIP processing program 301 (S411: YES), the extended image conversion program 302 currently being executed waits for the page being processed to be completed, and when completed (S412: YES), the extended image conversion program 302 is suspended (S413), and the RIP processing program 301 is activated (S414).

In the extended image conversion program 302, as in the case of the RIP processing program 301, when the page is a page other than the last page, the switch control program 300 is notified of this every time the extended image conversion for each page is completed. Then, the extended image conversion may be continued after waiting for an instruction from the switching control program 300.
If the extended image conversion program 302 is not being executed (S410: NO), the switching control program 300 immediately starts the RIP processing program 301 (S414). If priority is not given to the RIP processing program 301 (S411: NO), activation of the RIP processing program 301 is suspended (S415), and the extended image conversion program 302 is continuously executed (S416).

  After the processes in steps S407, S409, S414, and S416, the switching control program 300 sets a timeout time in the timer 204 and ends the process (S417). In the present embodiment, the switching control program 300 sets 15 seconds for the timer 204 as the timeout time. However, this timeout period is merely an example, and another timeout period may be set as necessary.

(2) Timeout processing Next, timeout processing executed by the switching control program 300 will be described.
FIG. 5 is a flowchart illustrating a timeout process executed by the switching control program 300. As shown in FIG. 5, if a timeout occurs in the timer 204 set in step S417 of FIG. 4 (S501: YES), whether either the RIP processing program 301 or the extended image conversion program 302 is suspended. To check. If there is a pending program (S502: YES), it waits until the currently executing program completes the page being processed.

  When the page being processed is completed (S503: YES), if the RIP processing program 301 is being executed (S504: YES), the RIP processing program 301 is suspended (S505), and the extended image conversion program 302 is executed. Execute (S506). Thereafter, a time-out time is set in the timer 204 (S507), the process proceeds to step S501, and the above process is repeated.

In step 507, the timer 204 is set to 30 seconds as the timeout time. This timeout time is also merely an example, and it goes without saying that another timeout time may be set as necessary.
If the extended image conversion program 302 is being executed (S504: NO), the extended image conversion program 302 is suspended (S508) and then the RIP processing program 301 is executed (S509). A timeout time of 30 seconds is set in 204, and the process proceeds to step S501 to repeat the above processing.

  If there is no pending program, the process of step S507 is not performed, and no timeout occurs in the sense that the timer 204 is not set. However, when a new RIP process or extended image conversion is executed, the flowchart of FIG. 4 is executed, so that the timer 204 is set in step S417 and a timeout occurs in step S501.

  In this way, since the shared area 310 is not occupied by any of the RIP processing program 301 and the extended image conversion program 302, the shared area 310 can be shared smoothly by these programs. In addition, since both the RIP processing program and the extended image conversion program 302 use the shared area 310 exclusively, there is no possibility of malfunction due to data overwriting.

Needless to say, since the RIP processing program 301 and the extended image conversion program 302 share the common area 310, the entire memory capacity of the image forming apparatus 1 can be reduced.
[5] Modifications As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and the following modifications can be implemented. .

(1) In the above-described embodiment, the case where the RIP processing program 301 and the extended image conversion program 302 are switched every predetermined time (30 seconds) has been described. Needless to say, the present invention is not limited to this. Instead of this, the following may be used.
If the time (deadline) at which processing should be completed for each program is set according to the elapsed time since the start of processing, etc., if the processing is not completed by the deadline, some error occurred. Therefore, there is a possibility that the error processing is started and the program is forcibly terminated or an error notification is given to the user.

  In addition, even when a health check requesting a response to the program periodically is made, if the program does not respond due to a reason that the program is in a wait state or the like, there is a possibility that an error is determined and the program is forcibly terminated. is there. In this health check, whether or not an error has occurred is determined based on whether or not there is a response from the program by a predetermined time (deadline).

For this reason, when the time to complete the process is set for each program, or when the health check of the program is performed at regular time intervals, the timer 204 is replaced with a constant time (30 seconds). Thus, the timer 204 may be set so that the program is switched prior to the scheduled completion time and the health check time.
Specifically, if there is one minute before the scheduled completion time, the timeout time is set to 50 seconds so that the program switches 10 seconds before that, for example, until a predetermined time before the scheduled completion time and the health check time. The timer 204 may be set so that a timeout occurs.

In this way, it is possible to prevent the operation of the other program from being hindered by the occupation of the shared area 310 by one program.
(2) In the above-described embodiment, the case has been described where the RIP processing program 301 is being executed and the processing of the page being processed is waited for to be switched to the extended image conversion program 302. When a long time is required for the processing, the execution of the extended image conversion program 302 is waited for a long time. Assuming such a case, the following may be performed.

FIG. 6 is a flowchart showing an operation at the time of job reception according to a modification of the present invention. In FIG. 6, when there is a step corresponding to FIG. 4, the same reference numeral is given or description is omitted. In the following, description will be given focusing on differences from the above embodiment.
As shown in FIG. 6, when the RIP process is being performed (S403: YES), a notification screen is displayed on the operation panel 210 (S601). FIG. 7 is a diagram illustrating a notification screen according to this modification. As shown in FIG. 7, the notification screen notifies that a memory access conflict between the RIP processing program 301 and the extended image conversion program 302 to the shared area 310 has occurred.

Further, this may cause the extended image conversion program 302 to wait for the creation of a CPDF file for a long time, and notification that the basic image conversion program 303 is executed instead of the extended image conversion program 302 is notified.
Then, the basic image conversion program 303 is started (S602). Since the basic image conversion program 303 uses the basic image conversion area 311 and does not use the shared area 310, the basic image conversion program 303 can be executed without causing a memory access conflict even during RIP processing. Therefore, a PDF file can be created promptly without waiting for completion of the RIP process.

If the RIP process is not in progress (S403: NO), the extended image conversion program 302 is immediately started (S603). Even in this case, since there is no competition for memory access to the shared area 310, a CPDF file can be created promptly.
In this way, it is possible to reduce the waiting time of the user at the time of reading the document and prevent white spots in the CPDF file.

(3) Assuming a case where a long time is required for the RIP processing of the page being processed, the following may be performed.
FIG. 8 is a flowchart showing an operation at the time of job reception according to a modification of the present invention. In addition, in FIG. 8, when there exists a step corresponding to FIG. 4, the same code | symbol is provided or description is abbreviate | omitted. In the following, description will be given focusing on differences from the above embodiment. In this modification, the RIP processing program 301 records the time required for the RIP processing of the page every time the RIP processing for one page is completed.

  As shown in FIG. 8, when priority is given to the extended image conversion process (S404: YES), each RIP processing time T of the page (completed page) for which the RIP process has been completed is referred to (S801). In this modification, since it is expected that there is a positive correlation between the RIP processing time for the completed page and the RIP processing time for the current page, if both the RIP processing times for the completed page are long, the RIP processing for the current page Estimated that the time is also long.

If any of the RIP processing times T of the completed page is less than the predetermined threshold value Tmax (S802: YES), the extended image is awaited for completion of the RIP processing (S405: YES) as in the above embodiment. Switch to conversion (S406, S407). On the other hand, if the RIP processing time T of the completed page is equal to or greater than the predetermined threshold Tmax (S802: NO), the current RIP processing page may also take time, and a confirmation screen is displayed on the operation panel 210. Is displayed (S803) and the user of the image forming apparatus 1 confirms whether to continue the RIP process or after the extended image conversion. FIG. 9 is a diagram illustrating a confirmation screen. As shown in FIG. 9, in the confirmation screen, a memory access contention to the shared area 310 between the RIP processing program 301 and the extended image conversion program 302 occurs, so that the CPDF file of the extended image conversion program 302 It is informed that there is a possibility that the creation will wait for a long time.

If a PDF file is created instead of the CPDF file, the data compression rate is low and the file size becomes large. However, the basic image conversion program 303 does not access the shared area 310, so the PDF does not have to wait for completion of the RIP processing. You can create a file. Therefore, it is also notified that the file creation time can be shortened.
After receiving the above notification, the user of the image forming apparatus 1 is asked to select whether or not to change the creation of the CPDF file to the creation of the PDF file. When the soft key 901 is pressed, since the basic image conversion is selected (S804: YES), the basic image conversion program 303 is operated instead of the extended image conversion program 302 (S805).

On the other hand, when the user instructs not to change to PDF file creation by pressing the soft key 902 (S804: NO), the process proceeds to step S405 and waits for completion of the RIP processing of the current page ( (S405: YES), the RIP processing program 301 is suspended (S406), and the extended image conversion program 302 is started (S407).
In this way, even if the RIP processing program 301 is likely to occupy the shared area 310 for a long time, instead of creating the CPDF file by the extended image conversion program 302, the basic image conversion program By creating a PDF file at 303, the waiting time of the user of the image forming apparatus 1 can be shortened.

Needless to say, the method of estimating whether or not the RIP processing takes a long time is not limited to the method of estimating from the processing time of the completed page, but may be estimated by other methods. For example, when the total time required for the RIP process for the completed page exceeds a predetermined time, it may be estimated that the RIP process for the source page takes a long time.
Further, the length of the RIP processing time of the current page may be estimated based on whether or not the longest processing time of the RIP processing time of the completed page is equal to or longer than the predetermined time. Conversely, the shortest RIP processing time is predetermined. The length of the RIP processing time of the current page may be estimated based on whether or not it is longer than the time. Also, as in the above modification, when the RIP processing is not in progress (FIG. 6, S403: YES), a confirmation screen (FIG. 9) may be displayed to allow the user to select whether to create a CPDF file or a PDF file. If the RIP processing time T on the previous page is equal to or greater than the threshold Tmax (FIG. 8, S802: NO), a notification screen (FIG. 7) is displayed, the basic image conversion program 303 is started, and the PDF file is saved. You may create it. Even if it does in this way, the same effect can be acquired.

  (4) In the above embodiment, the case where the RIP processing program 301 or the extended image conversion program 302 switches the program at the timing when the processing for one page is completed has been described. However, the present invention is not limited to this. Needless to say, the following may be used instead. For example, the program being executed by the switching control program 300 may be forcibly waited and the other program may be started after the stored contents of the shared area 310 are backed up to the HDD 203. Even if it does in this way, the effect similar to the said embodiment can be acquired.

In a system in which the operation of the RIP processing program 301 and the extended image conversion program 302 can be stopped and restarted by assigning the right to use the shared area 310, the switching control program 300 assigns the right to use the shared area 310. The process may be switched by switching the.
(5) In the above embodiment, the case where the extended image conversion program 302 is uniformly started when the image forming apparatus 1 accepts a scan job has been described. However, the present invention is not limited to this. Instead, the following may be used instead.

FIG. 10 is a flowchart showing an operation at the time of job reception of the control unit 112 according to this modification. In FIG. 10, when there is a step corresponding to FIG. 4, the same reference numerals are given or the description is omitted. In the following, description will be given focusing on differences from the above embodiment.
As shown in FIG. 10, when there is a scan job (S402: YES), it is confirmed which one of extended image conversion and basic image conversion is designated in the scan job. This designation is input by the user of the image forming apparatus 1 on the operation panel 210, for example. If extended image conversion is designated (S1001: YES), the processing from step S403 to S407 is executed as described in the above embodiment.

  If basic image conversion is designated in the scan job (S1001: NO), the basic image conversion program 303 is immediately started (S1002). In this way, the basic image conversion is also performed according to the user's request without performing the extended image conversion uniformly, so that the memory access contention to the shared area 310 can be alleviated. Therefore, the delay of RIP processing can be reduced.

(6) In the above embodiment, the case where the extended image conversion program 302 shares the shared area 310 with the RIP processing program 301 has been described, but it goes without saying that the present invention is not limited to this. Instead of this, another program may share the shared area 310 with the RIP processing program 301.
For example, when the image forming apparatus 1 has a facsimile communication function, a program for converting raster image data output from the document reading unit 100 into facsimile image data, which is converted into high-definition facsimile image data. The RIP processing program 301 and the shared area 310 may be shared by the high-definition conversion program.

FIG. 11 is a diagram illustrating a configuration of software that shares a memory area. As illustrated in FIG. 11, the control unit 112 executes a switching control program 300, a RIP processing program 301, a high-definition conversion program 1101, and a standard conversion program 1102. The RIP processing program 301 uses the shared area 310 as a working storage area.
The high-definition conversion program 1101 converts raster image data output from the reading unit 100 into high-definition resolution facsimile image data. In the present embodiment, the high definition conversion program 1101 executes G4 compression. The high definition conversion program 1101 uses both the common area 310 and the standard conversion area 1111.

In the above embodiment, the enlarged image conversion program 302 uses the shared area 310 for G4 compression and the basic conversion area 311 for JEPG compression. However, the high-definition conversion program 1101 uses the shared area 310 and the standard area. The conversion area 1111 is used for G4 compression without being distinguished.
The standard conversion program 1102 converts raster image data into standard resolution facsimile image data by G3 compression. In this case, the standard conversion program 1102 uses only the standard conversion area 1111 as a working storage area.

  FIG. 12 is a flowchart showing processing by the switching control program 300 according to this modification. As shown in FIG. 12, the control program 301 according to this modification is similar to the RIP processing program that the control program 301 according to the above embodiment switches between the RIP processing program 301 and the extended image conversion program 302. 301 and high-definition conversion program 1101 are switched.

  In this way, since the RIP processing program 301 and the high definition conversion program 1101 share the common area 310, the memory capacity can be reduced. In addition, since both the RIP processing program and the high-definition conversion program 1101 use the shared area 310 exclusively, there is no possibility of malfunction due to data overwriting.

  The image forming apparatus according to the present invention is useful as an apparatus having a reduced memory capacity for processing image data and the like.

1 ……………… Image forming apparatus 100 ………… Document reading unit 110 ………… Image forming unit 112 ………… Control unit 200 ………… CPU
202 ......... RAM
204 ......... Timer 206 ......... FAX Modem 210 ......... Operation Panel 300 ......... Switching Control Program 301 ......... RIP Processing Program 302 ......... Extended Image Conversion Program 303 ......... Basic image conversion program 310 ......... Shared area 311 ......... Basic image conversion areas 901 and 902 ... Soft key 1101 ... High-definition conversion program 1102 ... Standard Conversion program 1111 ... Standard conversion area

Claims (13)

An image forming apparatus having an original reading unit for reading an image from an original,
RIP processing means for performing RIP processing on the image data to be formed using the first memory area;
Basic image conversion means for performing basic image conversion processing, which is image conversion processing that uses only a second memory area that does not overlap the first memory area, for image data read by the original reading means;
For the image data read by the original reading means, an extended image conversion process, which is an image conversion process that has a higher compression rate or resolution than the basic image conversion process, is added to the second memory area. Extended image conversion means using at least a part of the first memory area;
An image forming apparatus comprising: a switching unit that switches between the RIP processing unit and the extended image conversion unit so that access to the first memory area does not compete. The basic image conversion process is a process of converting image data read by the document reading unit into PDF data,
The image forming apparatus according to claim 1, wherein the extended image conversion process is a process of converting image data read by the document reading unit into CPDF data. The basic image conversion process is a process of converting image data read by the document reading unit into facsimile image data by G3 compression,
2. The image forming apparatus according to claim 1, wherein the extended image conversion process is a process of converting image data read by the document reading unit into facsimile image data by G4 compression. The switching control means further includes
The process according to any one of claims 1 to 3, wherein when either one of the RIP processing means and the extended image conversion means executes a process and the other is waiting, the process is switched at regular intervals. The image forming apparatus according to any one of the above. For each of the RIP process, the basic image conversion process, and the extended image conversion process, a timeout process unit that executes a timeout process when a predetermined timeout period is exceeded during the process,
As the time-out process, the switching unit waits until the page being processed is completed for the incomplete process when either the RIP process or the extended image conversion process is incomplete, and performs the RIP process and the extended image conversion process. 5. The image forming apparatus according to claim 1, wherein the image forming apparatus is switched so that the process that is being executed is suspended and the other process is executed. 6. The switching control means further includes
5. The image forming apparatus according to claim 4, wherein the switching is performed depending on which of the RIP processing unit and the extended image conversion unit uses the first memory area. The switching control means further includes
7. The image forming apparatus according to claim 4, wherein the switching is performed every time a process being executed is completed in units of pages. The switching control means further includes
2. The image processing apparatus according to claim 1, wherein when the document reading unit reads image data to be processed during the RIP processing, the basic image conversion unit performs processing instead of the extended image conversion unit. The image forming apparatus according to claim 6. In the RIP process, when the document reading unit reads the image data to be processed, the determination unit includes a determination unit that determines the length of time required to wait for the RIP process.
The switching control means further includes
The process according to any one of claims 1 to 6, wherein when the determination unit determines that a long time is required, the basic image conversion unit performs processing instead of the extended image conversion unit. Image forming apparatus. 10. The image forming apparatus according to claim 8, further comprising a notifying unit that notifies a user when the basic image converting unit performs processing instead of the extended image converting unit. An accepting means for accepting from the user an instruction as to whether or not to perform processing in the basic image converting means instead of the extended image converting means when the determining means determines that a long time is required;
When the negative instruction is received by the receiving means, the switching control means is prohibited from performing processing by the basic image converting means instead of the extended image converting means, and the extended image converting means The image forming apparatus according to claim 9, further comprising a prohibiting unit that performs processing. The determination means includes
Of the pages according to the prior Symbol R IP process, according to claim 9 or 11 processing time of the page RIP process is complete depending on whether it is more than a predetermined time, and judging the length of processing time Image forming apparatus. The determination means includes
Of the pages according to the prior Symbol R IP processing, depending on whether the total time of the processing time of the page RIP process is completed is longer than a predetermined time, according to claim 9, characterized in that to determine the length of processing time or The image forming apparatus according to 11.

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