JP6747381B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus that performs image processing.

Some image forming apparatuses perform printing based on the received print data. For example, the image forming apparatus rasterizes the received print data. As a result, image data is generated. Then, the generated image data is held in the storage area. The storage area is provided in the RAM, for example. By holding the data in the storage area, it is possible to prevent the rasterization process from being repeated when printing a plurality of copies. However, the size of the storage area is finite. Therefore, the image data of one page of all pages may not be stored in the storage area. Patent Document 1 describes a technique for coping with such a memory full of a storage area.

Patent Document 1 describes a printing system including a printing device that performs a printing process according to print data received from an information processing device connected via a network. The printer of this system receives the print data, analyzes the print data, generates print image data according to the result of the analysis, stores the image data, prints on the paper according to the image data, and prints the same print data. When printing a plurality of copies, printing is performed using the stored image data, and when the capacity of the storage area is exceeded, the information processing apparatus is requested to retransmit the print data. When the capacity of the storage area is exceeded, the printing apparatus erases all the image data that is currently stored and has been printed. Then, after the memory in the image data storage area is full, the image data is not retained. When printing of one page is completed, the operation is performed while erasing the corresponding image data. The information processing device retransmits the print data in response to the retransmission request. When another print data is received while receiving the retransmitted data after transmitting the retransmit request, the printing apparatus prints the retransmitted data with priority (Patent Document 1: Claim 1, paragraph [0051], [Patent Document 1]. 0052] etc.).

JP, 2007-055024, A

Storage may be provided in the image forming apparatus. The storage is a mass storage device such as an HDD. The storage stores image data. When printing, image data is read from the storage into a dedicated storage area of the RAM. Image processing for printing is applied to the read image data. Printing is performed based on the image data after the image processing.

The printing speed of the image forming apparatus is affected by the reading speed of image data from the storage to the storage area. In other words, the number of printed sheets of the image forming apparatus per unit time cannot be larger than the number of pages of image data that can be prepared in the storage area per unit time. When the number of pages of image data that can be prepared in the storage area per unit time <the number of printable pages of the image forming apparatus per unit time, the printing speed of the image forming apparatus is reduced.

Further, in the case of a print job for printing a plurality of copies, the image data read from the storage may be held in the storage area. This makes it possible to prevent repeated reading of the same image data. From the second copy onward, image processing can be started immediately for the image data held in the storage area.

Here, there are cases where the image data of one copy of all pages cannot be stored in the storage area. Conventionally, when the memory is full, the image data stored in the storage area is cleared. The held image data of the printed page is deleted. Then, in printing the second and subsequent copies, reading of each page from the storage to the storage area is repeated. As a result, when the image data of one copy of all pages cannot be stored in the storage area, the printing speed of the image forming apparatus is used for printing the second and subsequent copies depending on the number of image data pages that can be prepared in the storage area per unit time. There is a problem that you have to lower.

In the technique described in Patent Document 1, when the memory full in the image data storage area occurs, all the image data currently stored and printed are erased. Then, after the memory is full, the image data is read into the RAM page by page. Therefore, the printing device described in Patent Document 1 includes the above-mentioned problems. The above problems cannot be solved.

In view of the above problems of the prior art, the present invention improves the number of printed sheets per unit time of the second and subsequent image forming apparatuses even when the image data of one page of all pages cannot be stored in the area provided in the RAM. Let

In order to achieve the above object, an image forming apparatus according to a first aspect includes a storage, a RAM, an image processing unit, a printing unit, and a control unit. The storage stores image data in a non-volatile manner. The RAM is provided with an image storage area for storing first image data based on the image data read from the storage. The image processing unit processes the first image data stored in the image storage area to generate second image data. The printing unit stores an image on the sheet supplied from the sheet feeding unit based on the sheet feeding unit that stores the sheet and supplies the sheet one by one at the time of printing, and the second image data generated by the image processing unit. An image forming unit to be formed is included. In the case of a multi-copy print job that prints multiple copies for each copy, the control unit sequentially prints the first image data page by page in the image storage area when printing the first copy of the multi-copy print job. Remember. The control unit causes the image processing unit to start image processing of the first image data in which the entire page is stored in the image storage area. The control unit causes the first image data for a plurality of pages from the first page to be retained as retained data in the image storage area during the multiple-copy print job. When the first image data of all pages of one copy cannot be stored in the image storage area, the control unit does not cause the RAM to erase the held data during the multiple-copy print job. In the printing of the second and subsequent copies of the multi-copy print job, the control unit prints the pages from the first page to the last held page, which is the last page included in the held data, with the maximum number of prints per unit time. The printing section is caused to print at the maximum printing speed which is the number of sheets. The control unit is configured such that the total size of the first image data included in the held data does not become larger than the size of the holding area, and the number of pages of the first image data included in the held data is the maximum number. So that the held data is stored in the holding area. The holding area is an area excluding a predetermined reserved area from the image storage area. In the case of printing the second and subsequent copies of the multiple-print job, the control unit causes the image processing unit to generate the second image data based on the held data up to the final held page. Before the image processing unit starts image processing of the first image data of the final held page, the control unit sequentially acquires the first image data of the pages subsequent to the final held page in the reserved area. To memorize. The control unit causes the printing unit to print the page stored in the reserved area at the maximum printing speed.

According to the present invention, even if the image data of one copy of all pages cannot be stored in a specific area of the RAM, it is possible to increase the number of prints per unit time of the image forming apparatus for the second copy and thereafter.

FIG. 1 is a diagram showing an example of a multifunction machine according to an embodiment. FIG. 1 is a diagram showing an example of a multifunction machine according to an embodiment. FIG. 6 is a diagram showing an example of a flow of processing of image data of the multifunction peripheral according to the embodiment. 6 is a flowchart illustrating an example of a flow of printing a first copy in the multi-function peripheral according to the embodiment. 6 is a flowchart illustrating an example of a flow of printing a first copy in the multi-function peripheral according to the embodiment. It is a figure which shows an example of the image storage area which concerns on embodiment. 6 is a flowchart illustrating an example of a flow of printing of a second copy and thereafter in the multifunction machine according to the embodiment. 6 is a flowchart illustrating an example of a flow of printing of a second copy and thereafter in the multifunction machine according to the embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In the following description, as an image forming apparatus, a multifunction peripheral 100 that prints using ink will be described as an example. However, each element such as the configuration and arrangement described in the present embodiment does not limit the scope of the invention and is merely an example for explanation.

(Structure of MFP 100)
First, an outline of a multifunction peripheral 100 (image forming apparatus) according to the embodiment will be described with reference to FIGS. 1 and 2. 1 and 2 are diagrams illustrating an example of the multifunction peripheral 100 according to the embodiment.

The multifunction device 100 includes a control unit 1. The control unit 1 includes a CPU 11 and an image processing unit 2. The multifunction device 100 also includes the storage unit 3. The control unit 1 controls each unit of the multifunction peripheral 100. The CPU 11 performs calculation and processing relating to control. The image processing unit 2 performs processing regarding the image data i0. The storage unit 3 includes a non-volatile storage device such as the ROM 31 and the storage 4. The storage 4 is, for example, an HDD. The storage unit 3 also includes a RAM 5. The storage unit 3 stores a control program and various data. The control unit 1 performs processing based on the programs and data stored in the storage unit 3.

The multi-function peripheral 100 includes a document feeding section 6a and an image reading section 6b. The document conveying section 6a automatically conveys the set documents one by one. The control unit 1 conveys the document to the document conveyance unit 6a toward the reading position (conveyance reading contact glass). The delivered document passes through the upper surface of the contact/reading contact glass provided on the upper surface of the image reading unit 6b.

The image reading unit 6b includes a stationary reading contact glass. The image reading unit 6b can also read a document set on the platen reading contact glass. The control unit 1 causes the image reading unit 6b to read (scan) the conveyed document or the document set on the placement reading contact glass. The image reading unit 6b generates image data i0 of the read document.

The multifunction device 100 includes an operation panel 7. The operation panel 7 includes a display panel 71, a touch panel 72, and hard keys 73. The control unit 1 causes the display panel 71 to display a screen regarding the job. Further, the control unit 1 causes the display panel 71 to display the operation image. The touch panel 72 and the hard keys 73 receive user operations. The user operates the display panel 71 (touch panel 72). As a result, various settings relating to the job can be made. For example, settings relating to a print job and a job execution start instruction can be performed.

As shown in FIGS. 1 and 2, the multifunction peripheral 100 includes a printing unit 8. The printing unit 8 includes a paper feeding unit 8a, a paper transporting unit 8b, and an image forming unit 8c.

The paper feed unit 8 a includes a paper feed tray 81, a paper feed roller 82, and a separation roller pair 83. The bundle of sheets is set in the sheet feed tray 81. The paper feed roller 82 is provided at the downstream end of the paper feed tray 81 in the paper transport direction. A separation roller pair 83 is provided on the downstream side of the paper feed roller 82 in the paper transport direction. The paper feed roller 82 and the separation roller pair 83 are rotated by a paper feed motor (not shown). At the time of paper feeding, the control unit 1 rotates the paper feeding motor. As a result, the sheets are sent out one by one from the paper feed tray 81 from the topmost sheet.

The separation roller pair 83 prevents double feeding of paper. The separating roller pair 83 includes a feed roller 83a and a retard roller 83b. The feed roller 83a conveys the paper in the forward direction (X direction in FIG. 2) toward the image forming unit 8c. The retard roller 83b returns the lower paper among the multi-fed papers to the paper feed tray 81.

The paper transport unit 8b transports the supplied paper. The paper transport unit 8b discharges the printed paper outside the machine (discharge tray 810). The paper transport unit 8b includes a transport belt 84, a drive roller 85, a driven roller 86, a transport motor 87, a suction unit 88, a discharge roller pair 89, and a discharge tray 810.

The belt unit 811 is provided on the downstream side (on the right side in FIG. 1) of the separation roller pair 83 in the sheet conveyance direction. The belt unit 811 includes a conveyor belt 84, a driving roller 85, and a driven roller 86. The conveyor belt 84 is stretched around a driving roller 85 and a driven roller 86. The axes of the rollers are parallel. At the time of printing, the control unit 1 rotates the carry motor 87. The transport motor 87 rotates the drive roller 85. As a result, the conveyor belt 84 circulates. The sheet on the transport belt 84 is transported in the forward direction (X direction in FIG. 2).

The suction unit 88 sucks the sheet on the transport belt 84. At the time of printing, the control unit 1 operates the suction unit 88. For example, the suction unit 88 applies a voltage to the driven roller 86. As a result, the transport belt 84 electrostatically attracts the paper. When releasing the electrostatic attraction, the control unit 1 causes the attraction unit 88 to ground the conveyor belt 84. The suction unit 88 may be a unit that sucks air and sucks the sheet onto the transport belt 84. The discharge roller pair 89 is provided on the downstream side of the transport belt 84 in the sheet transport direction. The discharge roller pair 89 is rotated by a discharge motor (not shown). At the time of printing, the control unit 1 rotates the ejection motor. The paper is discharged from the discharge roller pair 89 to the discharge tray 810.

The image forming unit 8c prints by ejecting ink onto the conveyance paper. As shown in FIGS. 1 and 2, the image forming unit 8c includes a plurality of line heads 9. Four line heads 9 (9C, 9M, 9Y, 9Bk) are provided. The line head 9C ejects cyan ink. The line head 9M ejects magenta ink. The line head 9Y ejects yellow ink. The line head 9Bk ejects black ink. An ink tank that supplies ink is provided for each line head 9.

Each line head 9 is fixed. Each line head 9 includes a plurality of nozzles. The nozzles are arranged in the main scanning direction (direction perpendicular to the paper transport direction). The interval between the nozzles in the main scanning direction is one pixel pitch. For example, in the case of the line head 9 corresponding to 600 dpi, the pitch is about 42 μm.

Each line head 9 is provided above the conveyor belt 84. The opening of each nozzle faces the conveyor belt 84. A constant gap is provided between each nozzle and the conveyor belt 84. Ink is ejected from the nozzle. The ink lands on the transport paper. The controller 1 moves the paper to the transport belt 84 by one pixel (one dot) during one ink ejection cycle. Further, the length of the line head 9 in the main scanning direction is longer than the width of the maximum size sheet that can be conveyed in the main scanning direction. One line in the main scanning direction is drawn in one ink ejection cycle. The multifunction peripheral 100 can print at a higher speed than a printing device in which the print head reciprocates left and right.

The controller 1 is connected to each line head 9. One drive element 91 (piezoelectric element) is provided for one nozzle (see FIG. 3). The drive element 91 is, for example, a piezo element or PZN. Each line head 9 includes a driver circuit 92 (see FIG. 3). The driver circuit 92 turns ON/OFF the voltage application to each drive element 91. In other words, the driver circuit 92 controls ejection and non-ejection of ink from each nozzle.

The control unit 1 (image processing unit 2) transmits the image data i0 to each driver circuit 92. The driver circuit 92 recognizes a nozzle that ejects ink and a nozzle that does not eject ink, based on the image data i0. The driver circuit 92 applies a pulsed voltage to the drive elements 91 corresponding to the nozzles that should eject ink. The shape of the driving element 91 is deformed by applying a voltage. The pressure of shape change is applied to a flow path (not shown) that supplies ink to the nozzle. Ink is ejected from the nozzle by the pressure on the flow path. The driver circuit 92 does not apply a voltage to the drive element 91 corresponding to the pixel that does not eject ink.

(Flow of processing of image data i0)
Next, an example of the processing flow of the image data i0 of the multifunction peripheral 100 according to the embodiment will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of a processing flow of the image data i0 of the multi-function peripheral 100 according to the embodiment.

In the following description, an example of the processing flow of the image data i0 during printing will be described. The multifunction peripheral 100 can perform a print job. The print job is a job for printing based on the print data received from the computer 200. The user operates the application installed in the computer 200. For example, when a user wants to print a document, he/she inputs a print command in the application being used by the computer 200. A mouse or a keyboard is used for command input, for example.

When the print command is input, the computer 200 generates print data. Printer driver software is installed in the computer 200. The CPU of the computer 200 generates print data based on the printer driver software. The print data is data described in a print page description language. The computer 200 transmits print data via the network to the communication unit 10 (see FIG. 1) of the multi-function peripheral 100.

The print data received by the communication unit 10 is input to the rasterization processing unit 2a (raster image processor). For example, the rasterization processing unit 2a is a circuit provided in the control unit 1. The rasterization processing unit 2a analyzes print data described in the page description language. Based on the analysis result, the rasterization processing unit 2a generates image data i0 for each page. For example, the rasterization processing unit 2a generates JPEG format image data i0. The control unit 1 stores the image data i0 generated by the rasterization processing unit 2a in the storage 4 in a nonvolatile manner.

Further, the multifunction peripheral 100 can perform a copy job. The copy job is a job for printing based on the image data i0 obtained by reading the original document by the image reading unit 6b. The user sets a document and operates the operation panel 7. When a scan start operation is performed on the operation panel 7, the control unit 1 causes the image reading unit 6b to read a document. The image reading unit 6b generates image data i0. For example, the image reading unit 6b generates JPEG format image data i0. The control unit 1 stores the image data i0 generated by the image reading unit 6b in the storage 4. As described above, the communication unit 10, the rasterization processing unit 2a, and the image reading unit 6b function as an input unit for inputting the image data i0 to the storage 4.

In the case of a print job, the control unit 1 reads the image data i0 used for printing page by page from the storage 4. The control unit 1 causes the RAM 5 to store the first image data i1 based on the read image data i0. The first image data i1 is the image data i0 before the image processing unit 2 performs image processing. An image storage area 50 is provided in the RAM 5. The image storage area 50 is an area for storing the first image data i1. The control unit 1 stores the first image data i1 in the image storage area 50. A part of the storage area of the RAM 5 is allocated to the image storage area 50. For example, about 30 to 40% of the storage area of the RAM 5 is assigned to the image storage area 50. Note that the other area stores, for example, the OS, software, programs, and data.

The multi-function device 100 includes a pre-processing unit 2b. The pre-processing unit 2b is a circuit that performs image processing on the image data i0 to generate the first image data i1. The pre-processing unit 2b is a circuit that performs a part of image processing necessary for generating the image data i0 (second image data i2) to be transmitted to the image forming unit 8c. For example, the preprocessing unit 2b performs image processing such as color conversion. The control unit 1 inputs the image data i0 read from the storage 4 into the pre-processing unit 2b. The pre-processing unit 2b performs image processing according to the print settings of the job. Then, the pre-processing unit 2b generates the first image data i1. The control unit 1 stores the first image data i1 generated by the preprocessing unit 2b in the image storage area 50.

The pre-processing unit 2b may not be provided depending on the specifications of the multifunction peripheral 100. For example, when the operating frequency of the image processing unit 2 is high, the pre-processing unit 2b may not be provided. This is because the image processing unit 2 can perform high-speed image processing, and it is not necessary to perform image processing before the image processing unit 2 performs processing. When the pre-processing unit 2b is not provided, the image processing unit 2 including the circuit (function, processing) of the pre-processing unit 2b is provided. In other words, the preprocessing unit 2b and the image forming unit 8c may be integrated. When the pre-processing unit 2b is not provided, the control unit 1 stores the image data i0 itself read from the storage 4 in the image storage area 50 as the first image data i1.

The image processing unit 2 processes the first image data i1 stored in the image storage area 50. The image processing unit 2 generates the second image data i2 based on the first image data i1. The image processing unit 2 performs image processing such as halftone processing. The second image data i2 is data (binary data) for instructing ejection or non-ejection of ink from each nozzle. The image processing unit 2 transmits the second image data i2 to the printing unit 8 (image forming unit 8c). Based on the second image data i2, the driver circuit 92 (driver circuit 92) of each line head 9 repeats drawing one line at a time. As a result, printing of one page is completed.

(Processing flow for multiple copy print jobs)
Next, with reference to FIGS. 4 to 6, an example of a processing flow of a multi-copy print job in the multifunction peripheral 100 according to the embodiment will be described. 4 and 5 are flowcharts illustrating an example of the flow of printing the first copy in the multifunction peripheral 100 according to the embodiment. FIG. 6 is a diagram showing an example of the image storage area 50 according to the embodiment. 7 and 8 are flowcharts showing an example of the flow of printing of the second and subsequent copies in the multifunction peripheral 100 according to the embodiment.

The multifunction peripheral 100 can perform a multiple-copy print job. The multiple-copy print job is a job for printing multiple copies one by one. For example, in the case of a print job, the number of copies to be printed can be set by the computer 200 (printer driver software). For a copy job, the number of copies can be set on the operation panel 7.

The flow of processing in printing the first copy of a multiple-copy print job will be described with reference to FIGS. 4 and 5. In the print job, the storage of the first image data i1 in the image storage area 50 and the generation and printing of the second image data i2 are executed in parallel. Storage of the first image data i1 in the image storage area 50 will be described with reference to FIG. The flowchart of FIG. 4 is a flowchart showing an example of the flow of storage of the first image data i1 in the first copy. Generation and printing of the second image data i2 will be described with reference to FIG. The flowchart of FIG. 5 is a flowchart showing an example of the flow of generation and printing of the second image data i2 for the first copy.

First, an example of the flow of storage of the first image data i1 in the image storage area 50 for the first copy will be described with reference to FIG. The start of FIG. 4 is the time when the printing of the first copy of a multiple-copy print job is started. Note that the control unit 1 may erase all the data in the image storage area 50 at the start point. Further, the control unit 1 may delete all the data in the image storage area 50 when the print job is completed. That is, the image storage area 50 is in a clear state at the start of the print job.

First, the control unit 1 stores the first image data i1 of the first page in the holding area 51 of the image storage area 50 (step #11). Here, the image storage area 50 will be described with reference to FIG. As shown in FIG. 6, the image storage area 50 is divided into a holding area 51 and a reserved area 52. The storage area 51 is an area excluding a predetermined reserved area 52 from the capacity of the image storage area 50. The control unit 1 sets the size of the holding area 51 so as to be larger than the size of the reserved area 52. The control unit 1 stores the first image data i1 in the holding area 51 in order from the first page. The control unit 1 stores the first image data i1 of the first half of the print job in the holding area 51. The size of the reserved area 52 is equal to or larger than the size of at least two pages, which is the predetermined maximum page size. The size of the reserved area 52 may be one page of the maximum page size. Note that the size of the first image data i1 almost never becomes the maximum page size. Normally, the reserved area 52 can store a plurality of pages of the first image data i1.

The maximum page size may be predetermined. For example, the theoretical maximum size of one image data i0 may be set as the maximum page size. The control unit 1 may also check the page size of each image data i0 stored in the storage 4. In this case, the control unit 1 sets the maximum size of the confirmed page sizes to the maximum page size.

Next, the control unit 1 confirms whether or not all pages have been stored in the image storage area 50 (step #12). In other words, the control unit 1 confirms whether or not the first image data i1 stored in the image storage area 50 immediately before is the first image data i1 of the last page of one copy (step #12). When it is the last page (Yes in step #12), this flow ends (end).

When it is not the last page (No in step #12), the controller 1 starts storing the first image data i1 of the next page in the holding area 51 (step #13). During storage in the holding area 51, the control unit 1 confirms whether or not the remaining capacity of the holding area 51 is insufficient (step #14). That is, the control unit 1 confirms whether or not the memory full in the holding area 51 has occurred.

When the remaining capacity is not insufficient (No in step #14), the control unit 1 completes the storage of the first image data i1 of the next page in the holding area 51 (step #15). After step #15, the flow returns to step #12.

When the entire page of the first image data i1 cannot be stored in the remaining area of the holding area 51 (when the remaining capacity is insufficient, Yes in step #14), the control unit 1 determines the first page of the stored page. One image data i1 is stored in the reserved area 52 (step #16). In this case, the control unit 1 may move the portion already stored in the holding area 51 to the reserved area 52. As described above, the control unit 1 causes the total size of the first image data i1 included in the holding area 51 to be less than the size of the holding area 51, and the page of the first image data i1 included in the holding area 51. The first image data i1 is stored in the holding area 51 so that the number becomes the maximum number.

After step #16, control unit 1 checks whether or not the first image data i1 of all pages have been stored in image storage area 50 (step #17). In other words, the control unit 1 confirms whether or not the first image data i1 stored in the reserved area 52 immediately before is the first image data i1 of the last page of one copy (step #17). When it is the last page (Yes in step #17), this flow ends (end).

When it is not the last page (No in step #17), the control unit 1 starts storing the first image data i1 of the next page in the reserved area 52 (step #18). During storage in the reserved area 52, the control unit 1 confirms whether or not the remaining capacity of the reserved area 52 is insufficient (step #19). That is, the control unit 1 confirms whether or not the memory full of the reserved area 52 has occurred.

When the remaining capacity is not insufficient (No in step #19), the control unit 1 completes the storage of the first image data i1 of the next page in the reserved area 52 (step #110). After step #110, the flow returns to step #17.

When the entire page of the first image data i1 cannot be stored in the remaining area of the reserved area 52 (when the remaining capacity is insufficient, Yes in step #19), the control unit 1 is stored in the reserved area 52. One or more of the first image data i1 stored in the RAM 5 are erased (step #111). For example, the control unit 1 causes the first image data i1 of the reserved area 52 to erase the first image data i1 of the page for which printing by the image forming unit 8c has finished. As a result, the control unit 1 secures an area required to store the entire first image data i1 of the next page. After that, the flow moves to step #110.

As shown in step #111, the control unit 1 deletes only the first image data i1 in the reserved area 52 among the first image data i1 in the image storage area 50. During the multiple-copy print job, the control unit 1 holds (does not delete) the first image data i1 in the holding area 51. Hereinafter, the first image data i1 stored in the holding area 51 will be referred to as holding data. FIG. 6 shows an example in which the first image data i1 of pages 1 to 15 of the print job is held data. The held data is a bundle of first image data i1 for a plurality of pages from the first page (first page). Note that, in FIG. 6, the first image data i1 of pages 16 to 20 is stored in the reserved area 52. During the print job, only the first image data i1 in the reserved area 52 is erased.

Next, an example of the flow of generation and printing of the second image data i2 for the first copy will be described with reference to FIG. The start in FIG. 5 is a time point when the printing of the first copy of the multiple-copy print job is started. At the start of FIG. 5, the control unit 1 sets n to 1 (n=1).

First, the control unit 1 continues to check whether or not the entire first image data i1 of the nth page is stored in the image storage area 50 (holding area 51) (No in step #21, step #21 → Step #21).

When the whole is stored (Yes in step #21), the control unit 1 causes the image processing unit 2 to start the image processing of the first image data i1 of the nth page (step #22). The image processing unit 2 generates the second image data i2 based on the first image data i1. Along with the start of image processing by the image processing unit 2, the control unit 1 causes the paper feeding unit 8a to start feeding the nth page of paper (step #23). As a result, the sheet is conveyed toward the image forming unit 8c. The control unit 1 rotates the paper feed roller 82 for a certain period of time. Then, the control unit 1 stops the paper feed roller 82 before starting to feed the next paper.

The control unit 1 causes the image processing unit 2 to transmit the second image data i2 toward the image forming unit 8c (each line head 9). For example, the control unit 1 causes the image forming unit 8c to transmit the second image data i2 line by line at a predetermined cycle. The control unit 1 causes the image forming unit 8c to perform printing based on the second image data i2. The image forming unit 8c prints on the conveyed paper.

Eventually, the image processing unit 2 completes the image processing of the nth page (generation of the second image data i2) (step #24). The control unit 1 confirms whether the image processing of all pages included in one copy is completed (step #25). When the image processing of all pages is completed (Yes in step #25), this flow ends (end). When the image processing of all pages is not completed (Yes in step #25), the controller 1 adds 1 to n (step #26). Then, the flow returns to step #21.

The number of printed sheets per unit time is affected by the developing speed of the first image data i1 in the image storage area 50. In other words, the number of printed sheets per unit time is related to the data reading speed from the storage 4. In the description below, the unit time is 1 minute. Further, the number of pages of the first image data i1 that can be prepared in the image storage area 50 by reading the image data i0 from the storage 4 per unit time is referred to as “the number of pages that can be prepared per unit time”.

The number of printed sheets per unit time cannot exceed the number of pages that can be prepared per unit time. The number of pages that can be prepared per unit time may be smaller than the maximum number of pages to be printed per unit time of the multi-function peripheral 100. The larger the size of each page of the first image data i1, the longer the storage time in the image storage area 50. Therefore, as the size of each page of the first image data i1 is larger, the number of pages that can be prepared per unit time tends to be smaller. The size of the first image data i1 differs for each page. For example, the size of the first image data i1 changes depending on factors such as vertical width, horizontal width, and resolution.

Therefore, the speed at which the first image data i1 is prepared in the image storage area 50 may not follow the printing speed. For example, the maximum number of prints per unit time of the multifunction peripheral 100 is 100 ppm (page per minute). The number of pages that can be prepared per unit time may be 90 ppm, for example. In some cases, the number of pages that can be prepared per unit time is smaller than the maximum number of prints per unit time.

When printing is performed so that the number of printed sheets per unit time becomes the maximum number of printed sheets, the paper feed interval is 60 (seconds)/100 (sheets)=0.6 seconds. When the paper feed interval is set in this way, the paper may reach the image forming unit 8c in a state where the second image data i2 is not ready. Therefore, in the first copy, the control unit 1 confirms the first image data i1 in which the entire page is stored (step #21). After the confirmation, the control unit 1 starts the image processing and paper feeding of the image processing unit 2. Accordingly, the paper feed interval of the paper from the paper feed unit 8a becomes a time corresponding to the interval for preparing the first image data i1. The number of printed sheets per unit time of the first copy may be about 90 ppm.

Next, the flow of processing for printing the second and subsequent copies of a multi-copy print job will be described with reference to FIGS. 7 and 8. FIG. 7 shows an example of the flow of storage of the first image data i1 in the image storage area 50. The start of FIG. 7 is a point of time when printing of the second and subsequent copies of a multi-copy print job is started. The flowchart of FIG. 7 is executed at the start of printing of each unit.

First, the control unit 1 confirms whether or not the holding area 51 includes the first image data i1 of one page of all pages (step #31). When the holding area 51 includes the first image data i1 of all pages (Yes in step #31), the necessary first image data i1 has been prepared. Therefore, when the holding area 51 includes the first image data i1 of all pages (Yes in step #31), this flow may end (end).

When the holding area 51 does not include the first image data i1 of all pages (No in step #31), first, the control unit 1 causes the RAM 5 to erase the unnecessary first image data i1 of the reserved area 52 ( Step #32). For example, the control unit 1 deletes the first image data i1 used in the printing of the previous copy in the reserved area 52. It should be noted that the first image data i1 of the page that has not been printed may be not erased in the previous copy. The control unit 1 also prohibits the erasing of the first image data i1 stored in the holding area 51 (step #33).

Subsequently, the control unit 1 recognizes the last page (final held page) of the held data (step #34). In the example of FIG. 6, the control unit 1 recognizes the 15th page as the last held page. Next, the control unit 1 stores the first image data i1 of the page next to the last held page in the reserved area 52 (step #35).

Next, the control unit 1 confirms whether or not all pages of one copy have been stored in the image storage area 50 (step #36). In other words, the control unit 1 confirms whether the first image data i1 stored in the image storage area 50 immediately before is the first image data i1 of the last page of one copy. When it is the last page (Yes in step #36), this flow ends (end).

When it is not the last page (No in step #36), the control unit 1 starts storing the first image data i1 of the next page in the reserved area 52 (step #37). During storage in the reserved area 52, the control unit 1 confirms whether or not the remaining capacity of the reserved area 52 is insufficient (step #38). In other words, the control unit 1 confirms whether the memory full of the reserved area 52 has occurred.

When the remaining capacity is not insufficient (No in step #38), the control unit 1 completes the storage of the first image data i1 of the next page in the holding area 51 (step #39). After step #39, the flow returns to step #36.

When the entire page of the first image data i1 cannot be stored in the remaining area of the reserved area 52 (Yes in step #38 when the remaining capacity is insufficient), the control unit 1 controls the first image of the reserved area 52. Of the data i1, unnecessary first image data i1 is erased in the RAM 5 (step #310). For example, the control unit 1 causes the first image data i1 of the reserved area 52 to erase the first image data i1 of the page for which printing by the image forming unit 8c has finished. When there is no first image data i1 of the page for which printing by the image forming unit 8c has finished, the control unit 1 waits until the printing ends. Then, the control unit 1 deletes the first image data i1 of the page immediately after printing is completed. As a result, the control unit 1 secures an area required to store the entire first image data i1 of the next page. After that, the flow moves to step #36.

Next, with reference to FIG. 8, an example of the flow of print processing for the second and subsequent copies of a multiple copy print job will be described. The start in FIG. 8 is a time point at which printing of each copy after the second copy of the multi-copy print job is started. First, the control unit 1 confirms whether or not the holding area 51 includes the first image data i1 of one page of all pages (step #41).

When the holding area 51 includes the first image data i1 of all pages (Yes in step #41), the control unit 1 determines that the number of prints per unit time is the maximum number of prints for all pages of one copy. As described above, the image processing section 2 is caused to perform the image processing of the first image data i1 (step #42). Further, the control unit 1 causes the printing unit 8 to print all pages of one copy at the maximum printing speed (step #43). After step #43, this flow ends (END).

Specifically, the control unit 1 performs image processing on the first image data i1 for one page per reference interval. The reference interval is the time obtained by dividing the unit time by the maximum number of prints. When the maximum number of printed sheets per unit time is 100 ppm, the reference interval is 0.6 seconds. The number of pages that the image processing unit 2 can process per unit time is equal to or larger than the maximum number of prints per unit time. The image processing unit 2 has the capability of following the maximum printing speed.

The maximum printing speed is the printing speed at which the number of printed sheets per unit time becomes the maximum number of printed sheets. When printing at the maximum printing speed, the control unit 1 causes the paper feeding unit 8a to start feeding paper at a reference interval. The control unit 1 may set the time when the image processing of the first image data i1 of the nth page is started to be the same as the time when the sheet feeding of the nth page is started.

When the holding area 51 includes the first image data i1 of all pages, step #41 is No. In other words, when the number of pages of one copy is larger than the number of pages of the held data, step #41 becomes No. When Step #41 is No, the control unit 1 causes the image processing unit 2 to set the first print number to the maximum print number per unit time from the start of printing the first page to a predetermined speed adjustment point. Image processing of the image data i1 is performed (step #44). Specifically, the control unit 1 performs image processing on the first image data i1 for one page at the reference interval. Further, the control unit 1 causes the printing unit 8 to print at the maximum printing speed from the start of printing the first page to the speed adjustment time (step #45). Specifically, the control unit 1 causes the paper feeding unit 8a to start feeding one page at a reference interval.

The speed adjustment time point is a time point when the image processing interval and the paper feeding interval should be longer than the reference interval. In other words, the speed adjustment time point is a time point when the number of pages of the first image data i1 processed by the image processing unit 2 should be reduced per unit time. Further, the speed adjustment time point is a time point when the number of printed sheets per unit time should be reduced from the maximum number of printed sheets. When the supply of the second image data i2 is becoming too late, the image processing interval and the paper feed interval are adjusted.

Specifically, the speed adjustment time point is a time point after the image processing of all the pages of the held data is completed. Further, the speed adjustment time is a time when the entire page is prepared in the reserved area 52 and the number of pages of the first image data i1 which is not image-processed by the image processing unit 2 becomes zero. It can be said that the speed adjustment time is the time when the margin based on the retained data is used up.

Then, control unit 1 confirms whether or not image processing of all pages included in one copy is completed (step #46). When the image processing for all pages has been completed by the time of speed adjustment (Yes in step #46), this flow ends (end).

When the image processing for all pages is not completed by the time of speed adjustment (No in step #46), the entire first image data i1 of the page to be processed next is stored in the image storage area 50 (holding area 51). The confirmation as to whether or not it is stored is continued (step #47, No in step #47→step #47). After the speed adjustment point has elapsed, image processing and paper feeding are performed according to the development speed of the first image data i1. As a result, the number of pages of the first image data i1 processed by the image processing unit 2 decreases per unit time. Further, the number of printed sheets per unit time becomes smaller than the maximum number of printed sheets. That is, the printing speed becomes slow.

When the entire image is stored (Yes in step #47), control unit 1 starts image processing of the first image data i1 newly read in reserved area 52 (step #48). The image processing unit 2 generates the second image data i2 based on the first image data i1. When the image processing unit 2 starts image processing, the control unit 1 causes the paper feeding unit 8a to start feeding paper (step #49). As a result, the sheet is conveyed toward the image forming unit 8c. Eventually, the image processing unit 2 completes the image processing of the first image data i1 newly read in the reserved area 52 (step #410). Then, the flow returns to step #46.

In this way, the image forming apparatus (multifunction peripheral 100) according to the embodiment includes the storage 4, the RAM 5, the image processing unit 2, the printing unit 8, and the control unit 1. The storage 4 stores the image data i0 in a non-volatile manner. The RAM 5 is provided with an image storage area 50 for storing the first image data i1 based on the image data i0 read from the storage 4. The image processing unit 2 processes the first image data i1 stored in the image storage area 50 to generate the second image data i2. The printing unit 8 stores an image on the paper supplied from the paper supply unit 8a based on the paper supply unit 8a that stores the paper and supplies the paper one by one at the time of printing, and the second image data i2 generated by the image processing unit 2. The image forming unit 8c that forms the image is included. In the case of a multi-copy print job that prints multiple copies for each copy, the control unit 1 stores the first image data i1 page by page in the image storage area 50 in order when printing the first copy of the multi-copy print job. Let The control unit 1 causes the image processing unit 2 to start the image processing of the first image data i1 in which the entire page is stored in the image storage area 50. The control unit 1 causes the image storage area 50 to retain the first image data i1 for the first to multiple pages as retained data during the multiple-copy print job. When the first image data i1 of all pages of one copy cannot be stored in the image storage area 50, the control unit 1 does not cause the RAM 5 to erase the held data during the multiple-copy print job. In the printing of the second and subsequent copies of the multi-copy print job, the control unit 1 determines that the pages from the first page to the last held page, which is the last page included in the held data, is the maximum number of printed sheets per unit time. The printing unit 8 prints at the maximum printing speed.

As a result, the held data can be continuously stored in the image storage area 50 of the RAM 5 during the multiple-copy print job. Even when the image data i0 of one page of all pages cannot be stored in the image storage area 50, the first page to the last page of the held data can be printed at high speed when printing the second and subsequent copies. Even if the number of pages of the image data i0 that can be prepared in the image storage area 50 per unit time is smaller than the printable number of pages per unit time, a plurality of sheets can be printed at high speed without fail.

Further, the control unit 1 does not cause the total size of the first image data i1 included in the held data to be larger than the size of the holding area 51, and the number of pages of the first image data i1 included in the held data is the maximum. The held data is stored in the holding area 51 so that the number becomes the number. The holding area 51 is an area obtained by removing the predetermined reserved area 52 from the image storage area 50. In the case of printing the second and subsequent copies of a multiple copy print job, the control unit 1 causes the image processing unit 2 to generate the second image data i2 based on the held data up to the last held page. Before the image processing unit 2 starts image processing of the first image data i1 of the last held page, the control unit 1 sequentially stores the first image data i1 of pages subsequent to the last held page in the reserved area 52. Let The control unit 1 causes the printing unit 8 to print the page stored in the reserved area 52 at the maximum printing speed. As a result, the number of pages of the first image data i1 stored in the holding area 51 can be maximized. Further, while the image processing unit 2 is performing the image processing of the first image data i1 in the holding area 51, the first image data i1 of the pages after the last holding page are sequentially read into the securing area 52. You can Therefore, the pages following the last held page can be printed at high speed. The printing speed of the image forming apparatus for the second and subsequent copies can be increased.

The size of the holding area 51 is larger than the size of the reserved area 52. This makes it possible to increase the number of pages that can be printed by the image forming apparatus without decreasing the printing speed in printing the second and subsequent copies.

The size of the reserved area 52 is equal to or larger than the size of at least two pages, which is the predetermined maximum page size. As a result, the problem that the entire first image data i1 cannot be read into the reserved area 52 does not occur. In addition, the first image data i1 of a plurality of pages can be stored in the reserved area 52.

The control unit 1 confirms the size of each page of the image data i0 stored in the storage 4. The control unit 1 sets the maximum size of the confirmed page sizes to the maximum page size. As a result, the size of the reserved area 52 can be set according to the page size of each image data i0 stored in the storage 4.

Further, in the printing of the second and subsequent copies of the multiple-copy print job, the control unit 1 sets the maximum print speed at which the number of prints per unit time becomes the maximum number of prints from the start of printing the first page to a predetermined speed adjustment point. The printing section 8 is made to print. The control unit 1 causes the printing unit 8 to print at a speed slower than the maximum printing speed up to the last page of the copy after the speed adjustment time has elapsed. The speed adjustment time is after processing the first image data i1 of the last held page. Further, the speed adjustment time is a time when the entire page is prepared in the reserved area 52 and the first image data i1 which is not image-processed by the image processing unit 2 becomes zero. As a result, in printing the second and subsequent copies, the printing speed can be reduced when the supply of the second image data i2 to the image forming unit 8c is becoming too late. The time when the image forming apparatus reduces the printing speed can be delayed as much as possible.

The image forming apparatus also includes a pre-processing unit 2b that reads the image data i0 from the storage 4 and performs image processing on the read image data i0. The control unit 1 stores the data processed by the pre-processing unit 2b in the image storage area 50 as the first image data i1. Thereby, the data obtained by processing the image data i0 can be stored as the first image data i1.

Although the embodiment of the present invention has been described above, the scope of the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.

INDUSTRIAL APPLICABILITY The present invention can be used for an image forming apparatus that processes and prints image data.

100 multifunction peripheral (image forming apparatus) 1 control unit 2 image processing unit 2b pre-processing unit 4 storage 5 RAM
50 image storage area 51 holding area 52 reserved area 8 printing section 8a paper feeding section 8c image forming section i0 image data i1 first image data i2 second image data

Claims (6)

A storage that stores image data in a nonvolatile manner,
A RAM provided with an image storage area for storing first image data based on the image data read from the storage;
An image processing unit that processes the first image data stored in the image storage area to generate second image data;
A paper feeding unit that accommodates the paper and supplies the paper one by one at the time of printing, and an image forming unit that forms an image on the paper fed from the paper feeding unit based on the second image data generated by the image processing unit. A printing section including
And a control unit,
For a multi-print job that prints multiple copies,
The control unit is
When printing the first copy of the multiple copy print job, the first image data is sequentially stored page by page in the image storage area,
Causing the image processing unit to start image processing of the first image data in which the entire page is stored in the image storage area,
During the multi-copy print job, the first image data for a plurality of pages from the first page is held in the image storage area as holding data,
When the first image data of all pages of one copy cannot be stored in the image storage area, the held data is not erased in the RAM during the multiple copy print job,
In the printing of the second and subsequent copies of the multiple-copy print job, the pages from the first page to the last held page, which is the last page included in the held data, is the maximum printed number per page Let the printing section print at a speed ,
In order that the total size of the first image data included in the held data does not become larger than the size of the holding area and the number of pages of the first image data included in the held data becomes the maximum number, Storing the holding data in the holding area,
The holding area is an area excluding a predetermined reserved area from the image storage area,
In the case of printing the second and subsequent copies of the multi-copy print job,
The control unit is
Up to the final holding page, the image processing unit is caused to generate the second image data based on the holding data,
Before the image processing unit starts image processing of the first image data of the final held page, the first image data of pages subsequent to the final held page are stored in the reserved area in order,
An image forming apparatus comprising Rukoto to print the pages stored in the reserved area on the printing unit with the maximum printing speed. The size of the holding area, the image forming apparatus according to claim 1, wherein greater than the size of the allocated area. The size of the reserved region, the image forming apparatus according to claim 1 or 2, characterized in that at least two pages larger than the size of the largest page size determined in advance. The control unit is
Check the size of each page of the image data stored in the storage,
The image forming apparatus according to claim 3 , wherein a maximum size of the confirmed page sizes is set to the maximum page size. In printing the second and subsequent copies of the multi-print job,
The control unit is
From the start of printing the first page to a predetermined speed adjustment point, the printing unit is caused to print at the maximum printing speed at which the number of printed sheets per unit time becomes the maximum number of printed sheets,
After the time of the speed adjustment time point, until the last page of the set, the printing unit is caused to print at a speed slower than the maximum printing speed,
At the time of the speed adjustment,
After processing the first image data of the last retained page,
An entire page is prepared in a predetermined reserved area in the image storage area , and the first image data that has not been subjected to image processing by the image processing unit is zero. the image forming apparatus according to any one of claims 1 to 4. A pre-processing unit that reads the image data from the storage and performs image processing on the read image data;
Wherein the control unit, the image forming apparatus according to any one of claims 1 to 5, characterized in that to store the data processed by the pre-processing unit in the image storage area as the first image data ..

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