JP2009118286A - Image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus prevented from decreasing in productivity owing to the transfer speed of a storage device. <P>SOLUTION: When the amount of compressed image data generated by compressing image data input from a scanner unit 11 etc., exceeds a threshold obtained from the previously measured transfer speed of a hard disk device 50, the image data are expanded and output without being routed through the hard disk device 50, but when the amount is equal to or less than the threshold, the image data are transferred to the hard disk device 50 to be temporarily stored, and then read out of the hard disk device 50 to be expanded and output. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms an image based on input image data, and more particularly, to an image forming apparatus that temporarily compresses and stores input image data and then decompresses the image data to form an image. .

  In recent years, in an image forming apparatus such as a digital copying machine, the speed of data, resolution, and color have progressed, and the amount of data handled has increased dramatically. For this reason, when storing image data, there is generally a method of compressing and storing the compressed image data and transferring and storing the compressed image data from a semiconductor memory to a large-capacity storage device such as a hard disk device with a relatively low bit unit price. It has been adopted.

  As described above, when the compressed image data is temporarily stored in a storage device such as a hard disk device, the input / output time (transfer speed) of the data to the storage device does not affect the productivity of image reading or printing. It is required to do.

  For example, since the access speed of a hard disk device is slower in the storage area on the inner circumference side than on the outer circumference side of the disk, the storage area for storing the compressed image data is selected according to the compression rate, so that the inner circumference and the outer circumference are selected. There is an image forming apparatus in which the difference in access speed from the above does not affect the productivity of the image forming apparatus (see, for example, Patent Document 1).

  In addition, in a device capable of distributing and storing image data in a plurality of hard disk devices including a removable hard disk device, an additional hard disk device is required when the transfer speed of the mounted removable hard disk device is a predetermined value or less. There is an image forming apparatus that prompts a necessary transfer speed to be ensured by displaying on a display (see, for example, Patent Document 2).

JP 9-247403 A JP 2006-121438 A

  In the case of complex pages where the photo portion occupies almost the entire surface, the compression rate is low and the amount of data is considerably large. Therefore, even if a high-speed storage area is selected in the hard disk device, the compressed image data is stored in the hard disk device. Therefore, it takes a long time to input and output, and the productivity of the image forming apparatus decreases.

  On the other hand, in a device that can use a plurality of hard disk devices in parallel, if the number of hard disk devices is increased so that productivity is maintained even with the above complicated pages, the number of the hard disk devices increases and the distributed processing becomes complicated. At the same time, the cost increases.

  In addition, since there is an individual difference in the transfer speed of a storage device such as a hard disk device, and the degree of decrease in productivity also varies according to the individual difference, an appropriate measure in consideration of the individual difference is required.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of preventing a reduction in productivity due to a transfer speed of a storage device.

  The gist of the present invention for achieving the object lies in the inventions of the following items.

[1] Input means for inputting image data;
Compression means for compressing the image data input from the input means;
First storage means for storing compressed image data output by the compression means;
Second storage means slower than the first storage means;
Decompression means for decompressing the compressed image data;
Image forming means for forming an image based on the image data after being decompressed by the decompressing means;
Control means for controlling the processing route of the image data;
With
The processing route includes a second route in which compressed image data stored in the first storage unit is transferred to and stored in the second storage unit, and then read from the second storage unit and decompressed by the decompression unit; There is a first route for decompressing the compressed image data stored in the first storage means by the decompression means without transferring to the second storage means,
The image forming apparatus, wherein the control unit processes compressed image data whose data amount exceeds a predetermined threshold value by the first route.

  In the above invention, when the amount of data after the input image data is compressed exceeds the threshold value, the image data is processed by the first route that does not pass through the second storage means that is slower than the first storage means. The threshold value is set to a minimum data amount or more that reduces the productivity of the image forming apparatus when the second storage unit is used.

[2] The image forming apparatus according to [1], wherein the threshold is set based on an actual measurement value of a transfer rate of the second storage unit.

  In the above invention, since the threshold value is set based on the actual measurement value, the individual difference in the transfer rate of the second storage device is reflected in the threshold value. The actual measurement may be performed, for example, when the apparatus is shipped from the factory, and the value obtained at that time may be stored in the nonvolatile memory, or may be updated by performing an actual measurement at predetermined intervals.

[3] Provided with an actual measurement means for performing the actual measurement,
The image forming apparatus according to [2], wherein the threshold value is set by performing an actual measurement by the actual measurement unit each time the image forming apparatus is powered on.

  In the above invention, the transfer speed of the second storage unit is measured every time the image forming apparatus is turned on, and the threshold value is re-determined based on the actually measured value, so that the usage status of the second storage device (for example, the occurrence status of fragmentation) ) Is reflected in the threshold value, and the threshold value can be set to a more accurate value.

[4] The control means determines the data amount of the compressed image data for each page, and processes the page where the data amount of the compressed image data exceeds the threshold value by the first route. 3]. The image forming apparatus according to any one of 3).

  In the above invention, based on the compressed data amount of each page, it is determined whether the page is processed by the second route or the first route.

[5] The control means processes the current page through the first route when the total amount of compressed image data of a plurality of predetermined pages including the current page exceeds a threshold value. The image forming apparatus according to any one of [1] to [3].

  In the above invention, whether the current page is to be processed by the second route or the first route is determined based on the total data amount of the compressed image data for the most recent predetermined pages including the current page. Even if the amount of data is large when viewed on the current page alone, the second route via the second storage means is selected if the total amount of data for the latest plurality of pages is less than or equal to the threshold value.

  According to the image forming apparatus of the present invention, when the amount of data after the input image data is compressed exceeds the threshold value, the image data is processed by the second route that does not pass through the low-speed second storage unit. While saving in the second storage device as much as possible, it is possible to avoid a decrease in productivity due to the transfer speed of the second storage device.

  Hereinafter, various embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 shows a cross-sectional configuration of an image forming apparatus 3 according to the first embodiment of the present invention. The image forming apparatus 3 includes an image forming apparatus main body 5, a large-capacity paper feeding device 6, and a post-processing device 7 connected to a subsequent stage of the image forming apparatus main body 5. The image forming apparatus 3 receives print data from an external device such as a personal computer or a copy function that optically reads an original and forms a duplicate image on the paper, and forms and outputs a corresponding image on the paper. This is a so-called digital multi-function device having a print function and the like.

  The image forming apparatus main body 5 includes a scanner unit 11 that reads a document image, an automatic document feeder 12 that feeds documents placed on a document tray 12a one by one to a document reading position of the scanner unit 11, and an image on a sheet. A printer unit 13 for forming and outputting and an operation display unit 14 are provided.

  A scanner unit 11 serving as an input unit for inputting image data includes a light source that irradiates light on a document, a line image sensor that reads the document for one line in the width direction, and a line image sensor that reflects reflected light from the document. The optical path includes a lens or a mirror that is guided to 11a to form an image. The scanner unit 11 can read a document in a state where the document is placed on the platen glass in addition to a flow reading format in which the document is conveyed by the automatic document feeder 12 while the document is moved relative to the reading position. . The scanner unit 11 functions as an image input unit.

  The printer unit 13 feeds paper from a plurality of paper feed trays 15 for storing paper for image formation, an image forming unit 16 for forming an image on the paper, and the large-capacity paper feeder 6 or the paper feed tray 15. The sheet conveying mechanism 17 is configured to pass through the image forming unit 16 and discharge the image forming unit 16 to the post-processing device 7 in the subsequent stage.

  The image forming unit 16 includes a photosensitive member 21, a charging device 22, a laser unit 23, a developing device 24, a transfer device 25, a separating device 26, a cleaning device 27, a fixing device 28, and the like. To form.

  Specifically, the photosensitive member 21 has a cylindrical shape and is rotated in a certain direction (the direction of arrow A in the drawing) by a driving unit (not shown). During rotation, the photosensitive member 21 is uniformly charged by corona discharge by the charging device 22, and then is scanned with laser light that is turned on / off according to image data from the laser unit 23, and an electrostatic latent image is formed on the surface thereof. Is formed. The developing device 24 visualizes the electrostatic latent image formed on the surface of the photoreceptor 21 as a toner image.

  The paper transport mechanism 17 feeds the paper from the large-capacity paper feed device 6 or the paper feed tray 15 and feeds it between the photoconductor 21 and the transfer device 25 at an appropriate timing (arrow B). The transfer device 25 electrostatically transfers the toner image formed on the surface of the photoconductor 21 onto the paper conveyed by the paper conveyance mechanism 17, and the separation device 26 removes the paper from the photoconductor 21 by static elimination. Isolate. The cleaning device 27 removes the toner remaining on the photoreceptor 21 after the transfer by rubbing with a blade or the like. The sheet on which the toner image has been transferred is further conveyed (arrow C), is heated under pressure when passing through the fixing device 28, and the toner image is fixed on the sheet, and then discharged to the post-processing device 7 ( Arrow D).

  The post-processing device 7 has a function of bundling a plurality of sheets and binding them with staples or making holes with punches. Note that the image forming unit 16 may form an image on a sheet by a method other than the electrophotographic method.

  FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus main body 5. The image forming apparatus main body 5 is configured by connecting a scanner unit 11, a printer unit 13, an operation display unit 14, and an image processing unit 60 to a main control unit 40 that performs overall control of the operation of the image forming apparatus main body 5. .

  The scanner unit 11 includes a scanner control unit 11b that controls the entire operation of the scanner unit 11 in addition to the line image sensor 11a shown in FIG. The printer unit 13 includes a laser diode (LD) 23a that is turned on / off according to image data, a printer control unit 13b that controls the operation of the entire printer unit 13 including the image forming unit 16 and the paper transport mechanism 17 and the like. have. In addition, although not shown, the printer control unit 13b is connected to each unit of the image forming unit 16 and a motor, solenoid, sensor, and the like that operate the paper transport mechanism 17.

  The operation display unit 14 functions to display various setting screens and operation screens to accept various setting / selection operations from the user, and to display various information and warnings to the user. The operation display unit 14 includes a display unit 14a including a liquid crystal display, an operation unit 14b including a touch switch and other switches laid on the screen, and an operation control unit 14c that controls the display unit 14a and the operation unit 14b. It is comprised.

  Although not shown, the scanner control unit 11b, the operation control unit 14c, and the printer control unit 13b each have a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM) as main parts. It is composed of a circuit, and executes various controls according to programs stored in the ROM.

  The main control unit 40 performs a function of performing overall control of the operation of the image forming apparatus 3, and includes a reading processing unit 41, a DRAM (Dynamic Random Access Memory) control unit 42, a compression IC 43a, a decompression IC 43b, and a semiconductor memory. An image memory 45, a writing processing unit 46, an image control CPU 47, a ROM 48, a nonvolatile memory 49, and a hard disk device 50 (also referred to as HDD) as second storage means are provided.

  The reading processing unit 41 has a function of performing enlargement processing, mirror image processing, binarization processing by error diffusion, and the like on the image data output from the scanner unit 11. The compression IC 43a compresses image data, and the decompression IC 43b functions to decompress the compressed image data (compressed image data) to the original image data. The compression method may be JPEG (Joint Photographic Experts Group) or the like, or an original method. The image memory 45 is used as a function as a page memory 45a capable of storing uncompressed image data in units of pages, a compression memory 45b serving as a first storage unit for storing compressed image data, and the like.

  The write processing unit 46 outputs a signal for turning on / off the laser diode 23a of the laser unit 23 according to the image data read out from the compression memory 45b and expanded at a timing according to the operation of the printer unit 13. The function to output to. The DRAM controller 42 controls read / write timing and refresh timing for the image memory 45 composed of dynamic RAM, compresses image data and stores it in the compressed memory 45b, and reads compressed image data from the compressed memory 45b and decompresses it. Control the timing when you do.

  The image control CPU 47 is a CPU that controls the entire operation of the image forming apparatus main body 5, and controls the functions for managing and controlling the processing route of image data, the functions for managing job reservation registration and job execution, and the like. Acts as a means. The image control CPU 47 operates according to a program stored in the ROM 48. In addition to the above programs, the ROM 48 stores test image data for actually measuring the transfer speed of the hard disk device 50. The non-volatile memory 49 is a memory that stores user data and system data that should be stored even after the power is turned off, an actually measured transfer rate, a threshold value that serves as a reference for comparing the amount of data, and the like.

  A PCI (Peripheral Component Interconnect) bus 44 is connected to the DRAM control unit 42, and a hard disk device 50 is connected to the PCI bus 44. The hard disk device 50 is a large-capacity rewritable nonvolatile storage device, and the data read / write speed (transfer speed or access speed) is lower than that of the image memory 45. The hard disk device 50 stores compressed image data transferred from the compression memory 45b, job setting information, and the like.

  An image processing means 60 is further connected to the PCI bus 44. The image processing means 60 receives print data from the external terminal 2 such as a personal computer and functions as a print controller that develops the print data into raster image data, and image data obtained by reading a document with the scanner unit 11. It functions as a scanner controller that transmits to the external terminal 2 or the like via e-mail or FTP (File Transfer Protocol) over the network. The image forming apparatus 3 can handle image data obtained by developing print data into raster image data by the image processing unit 60 and image data received through the network in the same manner as image data obtained by reading by the scanner unit 11. The image processing means 60 functions as an input means for inputting image data.

  The image processing means 60 includes a controller control CPU 61 that performs overall control of the above functions, a LANIF unit 62 that performs a communication function for connection to a LAN (Local Area Network), an image memory 63 that stores image data, and a hard disk device. 64 and a DRAM control unit 65. The DRAM control unit 65 performs read / write and refresh timing control for the image memory 63 formed of a dynamic RAM. Also, image data and the like are exchanged with the DRAM control unit 42 of the main control unit 40 through the PCI bus 44.

  Next, the processing route of image data will be described.

  The image data processing route includes a first route that does not pass through the hard disk device 50 and a second route that passes through the hard disk device 50. Hereinafter, the operation in each route will be described. Note that the processing from compressing the image data to storing it in the compression memory 45b is a common route.

<Image input processing by common route>
When the scanner unit 11 reads an original and inputs image data, the line image sensor 11a (input of image data) of the scanner unit 11 → reading processing unit 41 (various image processing) → compression IC 43a (compression) → DRAM control unit The image data is processed by the route of 42 → compression memory 45b, and the compressed image data is stored in the compression memory 45b. When inputting the image data developed by the image processing unit 60 by the printer function, the image memory 63 in the image processing unit 60 → the PCI bus 44 → the DRAM control unit 42 → the page memory 45a → the DRAM control unit 42 → the compression IC 43a The compressed image data is stored in the compression memory 45b through a route of (compression) → DRAM control unit 42 → compression memory 45b.

  After the image input processing by the common route is performed, it is selected whether the subsequent processing route is the first route or the second route. When the first route is selected, the image input process is completed when the storage into the compression memory 45b is completed. For example, the image input process is completed with the end of the common route. When the second route is selected, after the common route, the compressed memory 45b → the DRAM control unit 42 → the PCI bus 44 → the hard disk device 50 is transferred and stored so that the compressed image data is stored in the hard disk device 50. Is done.

<Image output processing by the first route>
When the output destination is the printer unit 13, the image data is decompressed by a route of compression memory 45 b → DRAM control unit 42 → decompression IC 43 b (decompression) → write processing unit 46 → laser diode (LD) 23 a of the printer unit 13. Is output. When the output destination is the external terminal 2 or the like, the compression memory 45b → DRAM control unit 42 → decompression IC 43b (decompression) → DRAM control unit 42 → page memory 45a → DRAM control unit 42 → PCI bus 44 → image of the image processing means 60 The data is processed by the route of the memory 63 and is further transmitted from the image memory 63 to the external terminal 2 through the LANIF unit 62.

<Image output processing by the second route>
The hard disk device 50 → the PCI bus 44 → the DRAM control unit 42 → the compressed memory 45b is transferred to and stored in the compression memory 45b, and then processed and output by the same processing route as the image output processing by the first route. The

  The image data for which the first route is selected as the processing route after the common route is output to the output destination in the image output processing of the first route. That is, when processing by the first route, the compressed image data stored in the compression memory 45 b is decompressed and processed by the decompression IC 43 b without being transferred to the hard disk device 50. The image data for which the second route is selected after the common route is transferred to the hard disk device 50 and stored (transfer storage processing), and then output to the output destination in the second route image output processing.

  For example, the copy operation by the first route is realized by a combination of the image input processing of the common route by the input from the scanner unit 11 and the image output processing of the first route having the printer unit 13 as the output destination. As a result, the image data obtained by reading the document by the scanner unit 11 is compressed by the compression IC 43a, temporarily stored in the compression memory 45b, read out from the compression memory 45b, decompressed by the decompression IC 43b, and laser diode (LD). The image is formed on the paper by the printer unit 13.

  The copy operation by the second route is realized by a combination of the image input processing of the common route by the input from the scanner unit 11, the transfer storage processing, and the image output processing of the second route having the printer unit 13 as the output destination. Is done. As a result, the image data obtained by reading the document by the scanner unit 11 is compressed by the compression IC 43 a and stored in the compression memory 45 b, further transferred, stored in the hard disk device 50, and then read from the hard disk device 50. The data is transferred to the compression memory 45b, decompressed by the decompression IC 43b, output to the laser diode (LD) 23a, and an image is formed on the paper by the printer unit 13.

  The printer function by the first route is realized by a combination of the image input processing of the common route by the input from the image processing means 60 and the image output processing of the first route having the printer unit 13 as the output destination. The printer function by the second route is realized by a combination of the image input processing of the common route by the input from the image processing unit 60, the transfer storage processing, and the image output processing of the second route having the printer unit 13 as the output destination. The

  The image control CPU 47 of the image forming apparatus body 5 functions to select and control whether the image data of each page is processed by the first route or the second route. Specifically, the image control CPU 47 initially performs image input processing for each page using a common route, and determines whether or not the data amount of the compressed image data after being compressed by the compression IC 43a exceeds a predetermined threshold value. If the data amount of the compressed image data is equal to or smaller than the threshold value, the second route is selected as the subsequent processing route, and the compressed image data of the page is transferred to the hard disk device 50 and stored. The image output process for this page is performed by the second route. When the data amount of the compressed image data exceeds the threshold value, the first route is selected, and the compressed image data is stored in the compression memory 45b without performing the transfer storage process to the hard disk device 50. Also, the image output process for this page is performed by the first route.

  Next, threshold setting will be described. The threshold is set based on an actual measurement value of the transfer rate of the hard disk device 50. In the ROM 48 of the main control unit 40, a predetermined amount of test image data to be used for actual measurement of the transfer rate is stored. The operation of transferring the data to the hard disk device 50 and storing it (see FIG. 3A) is performed, and the required time is measured. The test image data stored in the hard disk device 50 is read out and stored in the image memory 45 (compression memory 45b) (see FIG. 4A), and the required time is measured.

  The processing route for storing the test image data in the hard disk device 50 is ROM 48 → DRAM control unit 42 → PCI bus 44 → hard disk device 50. The processing route for reading the test image is hard disk device 50 → PCI bus 44 → DRAM control unit 42 → compression memory 45b.

  As shown in FIG. 3B, the image storage time is the time from when the image control CPU 47 makes a test image data storage request until the hard disk device 50 completes the image data storage processing. A timer is started when an image storage request is output, the timer is stopped when image storage is completed, and the time from the start to the stop is measured as the image storage time. The test image data is composed of image data for a plurality of pages. By saving a large amount of image data, the transfer speed is measured more accurately.

  As shown in FIG. 4B, the image reading time is the time from when the image control CPU 47 requests reading of test image data until the hard disk device 50 completes the reading process of the image data. A timer is started when an image read request is output, the timer is stopped when image read is completed, and the time from the start to the stop is measured as the image read time.

  FIG. 5 shows a flow of actual measurement processing for actually measuring the transfer speed of the hard disk device 50. First, it is determined whether or not to perform measurement (step S101). For example, when the image forming apparatus main body 5 is set to the measurement mode when the power is turned on, the measurement is performed when the power is turned on. Measurement is performed when a specific operation is performed from the operation display unit 14. The latter is performed, for example, when the apparatus is shipped from the factory. In addition, it is performed by a service person after shipment.

When measurement is not performed (step S101 ;; No), this process ends (end). When measurement is performed (step S101; Yes), the test image data is transferred from the ROM 48 to the hard disk device 50 and stored, and the image storage time required for the test image data is measured (step S102). Further, the test image data is read from the hard disk device 50 and stored in the compression memory 45b, and the image read time required for the test image data is measured (step S103). The transfer speed is calculated based on the longer one of the actually measured image storage time and image reading time (step S104). The transfer speed is
Transfer speed = (data amount of test image data) ÷ (the longer of image storage time and image readout time)
Ask for. For example, if the test image data is 20 MB and the longer time is 5 seconds, the transfer speed is 4 MB.

  The transfer rate is stored in the non-volatile memory 49 or the like as the actual transfer rate (step S105), and the process is terminated (END). If the measurement is set to be measured every time the power is turned on, the actually measured transfer speed need not be stored in the nonvolatile memory 49 but may be stored in the volatile memory. However, when the measurement is performed at the time of factory shipment or in response to a specific operation by a service person, the actual transfer rate obtained by the measurement needs to be stored in a nonvolatile manner, and is stored in the nonvolatile memory 49.

  Next, the determination (image transfer destination determination) of whether to process using the first route or the second route will be described.

  FIG. 6 shows the flow of the image transfer destination determination process. When the image data for one page input from the scanner unit 11 or the image processing means 60 through the common route is completely compressed by the compression IC 43a (step S201; Yes), the first data is based on the data amount of the compressed image data of the page. It is determined whether the productivity of the image forming apparatus 3 is ensured even when the page is processed in two routes (step S202).

For example, in the image forming apparatus 3 capable of outputting 60 sheets per minute, in order to ensure the productivity, the compressed image data per image surface needs to be read from the hard disk device 50 in less than one second. . Further, in the case where the storage and reading to one hard disk device 50 are performed simultaneously in parallel, the transfer speed is generally halved, so that the reading of the compressed image data per image surface is within 0.5 seconds. It is required to complete. Here, if the measured transfer rate is 4 MB, the amount of data that can be transferred in 0.5 seconds is 2 MB, and this value is set as a threshold value for determining whether or not productivity is ensured. That is,
Threshold value = actually measured transfer speed / calculated as time allowed for transfer per image. If the data amount of the compressed image data of the target page exceeds the threshold value, it is judged that the productivity is lowered. Judge that productivity is secured.

  If productivity is ensured (step S202; Yes), the second route is selected, and the compressed image data of the page is transferred from the compression memory 45b to the hard disk device 50 and stored (step S203). On the other hand, when the productivity is not ensured (step S202; No), the first route is selected. That is, the compressed image data is stored in the compression memory 45b without being transferred to the hard disk device 50 (step S204). In either case, the storage address of the compressed image data is stored as page information (step S205), and the process ends.

  The storage destination address is used for recognizing where the compressed image data of each page is stored in the image output process. The image output process for the page whose storage destination address indicates the hard disk device 50 is performed in the second route, and the image output process for the page whose storage destination address indicates the compression memory 45b is performed in the first route.

  If the storage location of the compressed image data output by the compression process in the compression IC 43a is a compression-dedicated memory area and the compressed image data needs to be moved and stored in another area, the compression is performed in step S204. Processing for transferring the image data from the compression-dedicated area to another area is performed. On the other hand, when the storage area of the compressed image data output in the compression process can be used as it is as a storage area, the compressed image data is stored as it is without being transferred to another area. In any case, when productivity is not ensured, the compressed image data is stored in the compression memory 45b, which is a semiconductor memory, and is not transferred to the hard disk device 50.

  As described above, since the page in which the amount of compressed image data exceeds the threshold is processed by the first route that does not pass through the hard disk device 50, the transfer rate of the hard disk device 50 becomes a bottleneck and the productivity of the image forming apparatus 3 is increased. Can be prevented from decreasing. Further, since the pages for which productivity is ensured are processed by the second route stored in the hard disk device 50, the memory capacity of the compression memory 45b can be reduced.

  Further, when the measured transfer rate is obtained every time the image forming apparatus 3 is turned on, even if the transfer rate changes depending on the usage status of the hard disk device 50 (for example, the occurrence status of fragmentation), a corresponding threshold is set. can do. On the other hand, if the measured transfer rate is obtained and stored in a nonvolatile manner at the time of factory shipment, etc., and the actual measurement is not performed when the power is turned on, the startup time of the device can be shortened by the amount that the actual measurement process is not performed when the power is turned on. it can.

[Second Embodiment]
In the first embodiment, the data amount of the compressed image data of the page is compared with the threshold value for each page. However, in the second embodiment, the compressed image data of the most recent predetermined pages including the current page is totaled. By comparing the data amount and the threshold value, it is determined whether or not the current page is to be processed by the second route. Other configurations are the same as those of the first embodiment, and a description of the same parts is omitted.

  In the second embodiment, the content of step S202 in the image transfer destination determination process is as follows. As in the case exemplified in the first embodiment, the image forming apparatus 3 considers the simultaneous processing of storing and reading at 60 sheets per minute so that the compressed image data per image is within 0.5 seconds. It is necessary to read the data, the actual transfer rate is 4 MB, and the data amount allowed per image is 2 MB. Also, the sum of the data amount for the latest five pages including the current page is compared with the threshold value. In this case, the threshold for determining whether or not productivity is secured is 2 MB × 5 10 MB.

  The total data amount of the compressed image data for the last five pages including the latest page (current page) for which image compression has been completed is compared with a threshold value. If the total data amount is equal to or less than the threshold value, it is determined that productivity is secured. The current page is processed by the second route. On the other hand, if the total data amount exceeds the threshold, it is determined that the productivity is lowered, and the current page is processed by the first route.

  In the case of FIG. 7, whether or not the fifth page is processed by the second route is determined by comparing the total data amount of the compressed image data for five pages from the first page to the fifth page with a threshold value. Is done. Whether the sixth page is to be processed by the second route is determined by comparing the total data amount of the compressed image data for five pages from the second page to the sixth page with a threshold value.

  As described above, the total amount of compressed image data for the predetermined plurality of pages including the current page is compared with the threshold value to determine whether or not the second route is to be processed. For example, even if the amount of data is large, if the total amount of data for the latest plurality of pages is equal to or less than the threshold value, the second route via the hard disk device 50 is selected. For example, when judging from the total data amount of the latest 5 pages, the current page has 5 MB (megabytes), but the previous 4 pages are 1 MB each, the total data amount for the latest 5 pages is 9 MB, and the threshold is 10 MB. If not, the current page is processed by the second route.

  Although various embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to that shown in the embodiments, and there are changes and additions within the scope not departing from the gist of the present invention. Is included in the present invention.

  In the embodiment, the storage device slower than the compression memory 45b is the hard disk device 50. However, other types of storage devices may be used.

  Further, although the threshold value is set based on the actually measured transfer rate, the threshold value may be set based on the transfer rate determined by the design specification or the like. The threshold value may have a certain margin. For example, when the calculated threshold value is 2 MB, the threshold value may be set to 1.5 MB with a margin.

  The actual measurement timing is not limited to when the power is turned on or a specific operation is performed, but may be arbitrarily determined. For example, the actual measurement may be performed according to the decrease in free space or the occurrence of fragmentation, or may be automatically performed at a specific time zone such as at night.

  In the embodiment, assuming that the saving and reading are performed at the same time, the transfer time allowed per image plane is halved. However, it is not necessary when the saving and reading are not performed simultaneously.

1 is an explanatory diagram illustrating a cross-sectional configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a block diagram showing an electrical configuration of an image forming apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the actual measurement sequence of image storage time. It is explanatory drawing which shows the actual measurement sequence of image reading time. It is a flowchart which shows the process which measures transfer time. It is a flowchart which shows an image transfer destination judgment process. It is explanatory drawing which shows the example which judges a processing route based on the total data amount of several pages.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... External terminal 3 ... Image forming apparatus 5 ... Image forming apparatus main body 6 ... Large capacity paper feeder 7 ... Post-processing apparatus 11 ... Scanner part 11a ... Line image sensor 11b ... Scanner control part 12 ... Automatic document feeder 12a ... Original Tray 13 ... Printer unit 13b ... Printer control unit 14 ... Operation display unit 14a ... Display unit 14b ... Operation unit 14c ... Operation control unit 15 ... Paper feed tray 16 ... Image forming unit 17 ... Paper transport mechanism 21 ... Photoconductor 22 ... Charging Equipment 23 ... Laser unit 23a ... Laser diode (LD)
24 ... Developing device 25 ... Transfer device 26 ... Separating device 27 ... Cleaning device 28 ... Fixing device 40 ... Main control unit 41 ... Reading processing unit 42 ... DRAM control unit 43a ... Compression IC
43b ... Extension IC
44 ... PCI bus 45 ... Image memory 45a ... Page memory 45b ... Compression memory 46 ... Write processing unit 47 ... Image control CPU
48 ... ROM
49 ... Nonvolatile memory 50 ... Hard disk device 60 ... Image processing means 61 ... Controller control CPU
62 ... LANIF unit 63 ... Image memory 64 ... Hard disk device 65 ... DRAM control unit

Claims (5)

Input means for inputting image data;
Compression means for compressing the image data input from the input means;
First storage means for storing compressed image data output by the compression means;
Second storage means slower than the first storage means;
Decompression means for decompressing the compressed image data;
Image forming means for forming an image based on the image data after being decompressed by the decompressing means;
Control means for controlling the processing route of the image data;
With
The processing route includes a second route in which compressed image data stored in the first storage unit is transferred to and stored in the second storage unit, and then read from the second storage unit and decompressed by the decompression unit; There is a first route for decompressing the compressed image data stored in the first storage means by the decompression means without transferring it to the second storage means,
The image forming apparatus, wherein the control unit processes compressed image data whose data amount exceeds a predetermined threshold value by the first route. The image forming apparatus according to claim 1, wherein the threshold is set based on an actual measurement value of a transfer rate of the second storage unit. The actual measurement means for performing the actual measurement,
The image forming apparatus according to claim 2, wherein the threshold value is set by performing an actual measurement by the actual measurement unit every time the image forming apparatus is powered on. 4. The control unit according to claim 1, wherein the control unit determines a data amount of the compressed image data for each page, and a page in which the data amount of the compressed image data exceeds a threshold is processed by the first route. The image forming apparatus according to one. The said control means processes the said current page by the said 1st route, when the data amount which totaled the compression image data for the last several predetermined pages containing a current page exceeds a threshold value. 4. The image forming apparatus according to any one of items 1 to 3.

Images