JP5895808B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an image forming apparatus and an image forming method.

  In recent years, improvement in processing capability of image forming apparatuses has been promoted.

  In a serial tandem type image forming apparatus in which two printing engines are connected in series, the front surface of a sheet is printed by a printing engine of a master unit, and the back side is printed by a printing engine of a slave unit located downstream in the sheet transport direction. As a result, the printing processing time on the paper is shortened and the processing capability of the apparatus is improved (Patent Document 1).

JP-A-2005-225123

  However, the image data for printing generated based on the print data in the controller is once transmitted to the parent device for all pages, and the image data of the page printed by the child device is transferred from the parent device to the child device. Further, if image data is not prepared in the slave unit at the paper passing timing of the slave unit, it is necessary to temporarily stop printing and wait for the image data to be prepared and resume printing. For this reason, if the size of the image data transferred from the master unit to the slave unit is large, there is a problem that the transfer time of the image data increases, the paper passing timing in the slave unit is delayed, and the print processing time increases.

  The present invention has been made to solve such problems. That is, the total amount of odd-numbered pages and even-numbered pages of image data generated from print data is obtained, the image data of the page with the larger total amount is printed by the master unit, and the image data with the smaller total amount is printed by the master unit. Transfer from to the handset. Thereby, the transfer time of image data from the master unit to the slave unit can be shortened, and the print processing time in the master unit and the slave unit can be reduced.

  The above-described problems of the present invention are solved by the following means.

  (1) A reception unit that receives print data, an image data generation unit that generates print image data from the print data received by the reception unit, and an odd number of the image data generated by the image data generation unit Analyzing means for analyzing the total amount of page data size and the total amount of data size of even pages, and transmitting the image data analyzed by the analyzing means to the first engine, and analyzing the odd page and even page In order to cause the first engine to print on one side of the paper based on the image data having the larger total data size analyzed by the means and to print on the other side of the paper after printing by the first engine, Control means for transferring the image data having a smaller total data size from the first engine to the second engine. Image forming apparatus.

  (2) The analysis unit further analyzes a print setting of the print data, and the control unit includes an odd page when the print setting analyzed by the analysis unit includes a specific print setting designated in advance. In order to cause the first engine to print on the one side of the sheet based on the image data of the first page and to print on the other side of the sheet after the first engine prints, The image forming apparatus according to (1), which is transferred to an engine.

  (3) The analysis unit further analyzes, for each sheet, a printing time of the image data by the first engine and a transfer time of the image data from the first engine to the second engine, and the control And means for completing the transfer of the image data from the first engine to the second engine for each sheet based on the printing time and the transfer time analyzed by the analyzing means, and the first engine. The image forming apparatus according to (1) or (2), wherein the first engine starts printing of the paper so that the time for completing the printing of the image data by (1) matches.

  (4) receiving print data (a), generating print image data from the print data received in step (a) (b), and generating the step (b) Analyzing the total amount of odd-numbered pages of image data and the total amount of even-numbered pages (c), and transmitting the image data to the first engine, the step (of the odd-numbered pages and even-numbered pages) In order to cause the first engine to print on one side of the paper based on the image data having the larger total data size analyzed in c) and to print on the other side of the paper after printing by the first engine And (d) transferring the image data having a smaller total data size from the first engine to the second engine.

  (5) The step (c) further analyzes a print setting of the print data, and the step (d) includes a specific print setting in which the print setting analyzed in the step (c) is designated in advance. If so, the first engine causes the first engine to print on the one side of the paper based on the odd page of the image data, and to print on the other side of the paper after printing by the first engine. The image forming method according to (4), wherein the image data is transferred to a second engine.

  (6) The step (c) further analyzes the printing time of the image data by the first engine and the transfer time of the image data from the first engine to the second engine for each sheet, In the step (d), the transfer of the image data from the first engine to the second engine is completed for each sheet based on the printing time and the transfer time analyzed in the step (c). The image forming method according to (4) or (5), wherein the first engine starts printing of a sheet so that the time and the time when the printing of the image data by the first engine is completed are the same.

  Obtain the total size of the odd and even pages of the image data generated from the print data, print the image data of the page with the larger total amount with the master unit, and print the image data with the smaller total amount from the master unit to the child unit. Transfer to the machine. Thereby, the transfer time of image data from the master unit to the slave unit can be shortened, and the print processing time in the master unit and the slave unit can be reduced.

1 is a block diagram illustrating an image forming system including a tandem type image forming apparatus according to a first embodiment of the present invention. It is a block diagram which shows the structure of client PC. 1 is a block diagram illustrating a configuration of a tandem type image forming apparatus according to a first embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration related to a printing process of the tandem image forming apparatus according to the first embodiment of the present invention. FIG. 6 is an explanatory diagram for explaining a reduction in print processing time by the tandem type image forming apparatus according to the embodiment of the present invention. 3 is a flowchart of an image forming method according to the first embodiment of the present invention. FIG. 7 is an explanatory diagram illustrating a relationship among a transfer time of image data from a parent device to a child device, a printing time in the parent device, and a printing time in the child device for one sheet.

  Hereinafter, an image forming apparatus and an image forming method according to embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing an image forming system including a tandem type image forming apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, the image forming system 1 includes a plurality of client PCs (Personal Computers) 2 a, 2 b, 2 c and a tandem type image forming apparatus 3.

  The tandem image forming apparatus 3 is a series tandem machine that performs printing on one side and the other side of a sheet by two printing engines connected in series. The client PCs 2a, 2b, and 2c may be configured by a plurality of PCs, or may be configured by a single PC.

  As shown in FIG. 1, the client PCs 2 a, 2 b, 2 c and the tandem type image forming apparatus 3 are connected via a network 4 so that they can communicate with each other. The network 4 is a LAN (Local Area Network) in which computers and network devices are connected according to standards such as Ethernet (registered trademark), token ring, and FDDI (Fiber-Distributed Data Interface), or LANs are connected by a dedicated line. It can be configured by a WAN (Wide Area Network).

  FIG. 2 is a block diagram showing the configuration of the client PC.

  As shown in FIG. 2, the client PCs 2a, 2b, and 2c include a CPU (Central Processing Unit) 21, a RAM (Random Access Memory) 22, a ROM (Read Only Memory) 23, an HDD (Hard Disk Drive) 24, and an operation unit. 25, a display unit 26, and a communication interface 27, which are connected to each other via a bus 28 for exchanging signals.

  The CPU 21 performs control of each unit and various arithmetic processes according to a program.

  The RAM 22 temporarily stores programs and data as a work area.

  The ROM 23 stores various programs and various data.

  The HDD 24 stores an operating system, a printer driver, and other various programs and various data. The printer driver converts the designated document file into a print job, performs print settings regarding the paper size and the tandem type image forming apparatus 3, and can issue a print instruction to the tandem type image forming apparatus 3 It is. A print job is a general term for a print command to the tandem type image forming apparatus 3, and includes print data and print settings. The print data is data of a document to be printed, and the print data can include various data such as image data, vector data, and text data. Specifically, the print data may be PDL (Page Description Language) data, PDF (Portable Document Format) data, or TIFF (Tagged Image File Format) data.

  The operation unit 25 includes a pointing device such as a mouse and a keyboard, and is used for performing various operations and inputs.

  The display unit 26 is a liquid crystal display, for example, and displays various types of information.

  The communication interface 27 is an interface for communicating with an external device, and is a network interface based on standards such as Ethernet (registered trademark), SATA (Serial Advanced Technology Attachment), PCI Express, USB, IEEE 1394, BLUETOOTH (registered trademark), IEEE 802. .11 or the like, a telephone line interface for connecting to a telephone line, or the like can be used.

  The user transmits a print job created by the printer driver in the client PC 2a, 2b, 2c from the client PC 2a, 2b, 2c to the tandem image forming apparatus 3 via the network 4, and the print job is transmitted from the tandem image forming apparatus 3 to the print job. A printed matter based on the can be output.

  FIG. 3 is a block diagram illustrating a configuration of the tandem type image forming apparatus.

  As shown in FIG. 3, the tandem type image forming apparatus 3 includes a CPU 31, a RAM 32, a ROM 33, an HDD 34, an external interface 35, an operation unit 36, a display unit 37, an image control unit 38, a reading unit 39, a first engine 40, a first engine. 2 includes an engine 41 and a post-processing unit 42. These components are connected to each other via a bus 43 for exchanging signals.

  The external interface 35 functions as receiving means, and the CPU 31, RAM 32, ROM 33, HDD 34, and image control unit 38 function as image data generating means, analyzing means, and controlling means.

  Note that the tandem type image forming apparatus 3 functions as an image forming apparatus. However, when the second engine is an external apparatus, the portion of the tandem type image forming apparatus 3 from which the second engine is removed is not included. It functions as an image forming apparatus.

  The CPU 31 performs control of the above constituent elements and various arithmetic processes according to a program. That is, the CPU 31 performs overall control related to various processes, printing, and storage while cooperating with each component configuring the tandem type image forming apparatus 3.

  The RAM 32 temporarily stores various data received through the network 4 or the reading unit 39. Various data stored in the RAM 32 are processed by the CPU 31 and transmitted to the HDD 34 and the image control unit 38 as necessary.

  The ROM 33 stores various programs and various data.

  The HDD 34 includes various programs including a program for the CPU 31 to control each component of the tandem image forming apparatus 3, print job data, image data generated by rasterizing the print data, and other Save various data. The program and data stored in the HDD 34 are read by the CPU 31 as necessary and executed or processed on the RAM 32.

  The external interface 35 is an interface for performing communication between the tandem type image forming apparatus 3 and an external device. The external interface 35 is a network interface based on standards such as Ethernet (registered trademark), SATA, PCI Express, USB, IEEE1394, or Bluetooth. (Registered trademark), various local connection interfaces such as a wireless communication interface such as IEEE 802.11, a telephone line interface for connecting to a telephone line, and the like are used.

  The operation unit 36 has various fixed settings such as a touch panel for performing various settings, a numeric keypad for setting the number of copies, a start key for instructing start of operation, a stop key for instructing stop of operation, a reset key for initializing various setting conditions, and the like. It consists of keys.

  The display unit 37 initializes a touch panel for displaying various information and inputting various settings, a numeric keypad for setting the number of copies, a start key for instructing start of operation, a stop key for instructing stop of operation, and various setting conditions. It consists of various fixed keys such as a reset key, and a display lamp. In addition, about the function which the operation part 36 and the display part 37 overlap, either the operation part 36 or the display part 37 may make it have the said function.

  The image control unit 38 performs layout processing and rasterization processing of print data included in the print job, and generates image data.

  Further, the image control unit 38 analyzes the total amount of odd page data sizes and the total amount of even page data sizes of the generated image data.

  The reading unit 39 applies light to a document set at a predetermined reading position on the document table with a light source such as a fluorescent lamp, and photoelectrically converts the reflected light with an imaging device such as a CCD (Charge Coupled Device) image sensor. Image data is generated from the electrical signal.

  The first engine 40 is a so-called master unit of the two print engines included in the tandem type image forming apparatus 3, and the second engine 41 is a combination of the two print engines included in the tandem type image forming apparatus 3. It is a so-called child machine. The second engine 41 that is a slave unit is located downstream of the first engine 40 that is the master unit in the paper transport direction. Hereinafter, the first engine 40 is referred to as a “master unit” 40 and the second engine 41 is referred to as a “slave unit” 41.

  The master unit 40 and the slave unit 41 print an image based on the image data on a sheet through the respective steps of charging, exposure, development, transfer, and fixing by an electrophotographic method. The master unit 40 and the slave unit 41 can increase the printing process speed by sharing the printing process with each other. For example, in double-sided printing, printing of one side of a sheet by the master unit 40 and printing of the other side of the sheet by the slave unit 41 can realize a high-speed printing process. That is, when the slave unit 41 is printing the other side of the sheet, the master unit 40 can print one side of the next sheet, thereby realizing high-speed printing.

  The post-processing unit 42 performs a bookbinding process such as a staple process on the printed matter printed by the master unit 40 and the slave unit 41 based on the print settings of the print job.

  The tandem image forming apparatus 3 according to the present embodiment operates as follows by having the above configuration.

  As described above, the image control unit 38 analyzes the total amount of odd page data sizes and the total amount of even page data sizes. Then, all the pages of the image data are once transmitted to the main unit 41 and printed on one side of the sheet based on the image data having the larger total data size among the odd and even pages of the transmitted image data. . Further, the image control unit 38 transfers the image data having the smaller total data size of the odd-numbered pages and the even-numbered pages to the slave unit 41 in order to print on the other side of the sheet after printing by the master unit. This suppresses the data size of the image data transferred from the master unit to the slave unit, thereby shortening the transfer time of the image data from the master unit to the slave unit and reducing the print processing time in the master unit and the slave unit. be able to.

  The configuration related to the printing process of the tandem type image forming apparatus 3 will be described in more detail.

  FIG. 4 is a diagram showing a configuration relating to the printing process of the tandem type image forming apparatus. Hereinafter, in order to simplify the description, the substantially same components in each configuration of the parent device 40 and the child device 41 will be described with the same reference numerals.

  The tandem type image forming apparatus 3 is provided with an ADF (Auto Document Feeder) 302, a scanner 304, and a touch panel 306 on an upper part of a main body 300. The main body 300 is provided with a printing unit 361 and can perform printing using toners of four colors of Y (yellow), M (magenta), C (cyan), and K (black).

  Under the printing unit 361, three paper feed trays T1 to T3 and T4 to T6 for storing paper are provided. In addition to the paper feed trays T1 to T3 and T4 to T6 provided in the main body, the tandem image forming apparatus 3 can include a paper feed unit having a large capacity paper feed tray. FIG. 4 shows an example provided with a paper feed unit. The paper feed unit includes three large capacity paper feed trays T7 to T9. In the paper feed trays T1 to T9, papers of different sizes and types can be accommodated to meet various printing needs.

  The printing unit 361 includes an image forming unit (Y, M, C, K) 360, an intermediate belt 362, a secondary transfer roller 364, a fixing unit 366, and the like. The image forming unit (Y, M, C, K) 360 forms a toner image on the intermediate belt 362.

  The image forming unit 360 includes an exposure unit, a developing unit, a photosensitive drum, and a primary transfer roller. At the time of printing, according to a PWM signal obtained by converting image data into PWM (Pulse Width Modulation), the exposure unit irradiates the photosensitive drum with laser light to form an electrostatic latent image. This is developed by the developing unit, and a toner image is formed on the photosensitive drum. The toner image on the photosensitive drum is transferred onto the intermediate belt by the primary transfer roller.

  The toner images of the respective colors formed by the image forming unit (Y, M, C, K) 360 are transferred to the same position on the rotating intermediate belt 362 and transferred onto the intermediate belt 362 from four color toners. A color image is formed. The paper is fed from one of the paper feed trays T1 to T9 at the timing when the color image on the intermediate belt 362 reaches the position of the secondary transfer roller. When the color image is transferred onto the paper by the secondary transfer roller and printed, the printed paper is conveyed to the fixing unit 366 and fixed.

  In duplex printing, after printing on one side of the sheet by the master unit 40, the sheet discharged from the fixing unit of the master unit 40 is conveyed to the slave unit 41 for printing on the other side. The sheet on which the other side is printed by the slave unit 41 is discharged from the main body 300.

  In the present embodiment, as described above, printing based on the image data having the larger total data size among the odd-numbered pages and the even-numbered pages of the image data is performed by the master unit 40, and the image having the smaller total data size is printed. Printing based on the data is performed by the slave unit 41. Accordingly, which print engine prints the odd-numbered pages and even-numbered pages of image data depends on the magnitude relationship of the total amount of data sizes of the odd-numbered pages and even-numbered pages. However, the orientation (face up / face down) of the printed paper discharged from the main body is unified to the orientation of the surface printed by either the parent device 40 or the child device 41. Therefore, odd-numbered pages and even-numbered pages do not coexist in the direction of the surface of the printed paper discharged from the main body.

  However, the print settings for the print job may include specific print settings for performing post-processing that is affected by the orientation of the printed paper surface. In this case, similarly to a general tandem type image forming apparatus, odd pages including the first page need to be printed by the master unit 40, and even pages need to be printed by the slave unit. Therefore, when such a specific print setting is included in the print settings of the print job, the odd page is the master unit 40 and the even number is an even number regardless of the total size of the data size of the odd and even pages of the image data. The page is printed on the slave unit. As specific print settings, for example, settings for stapling and settings for color printing only on odd pages are conceivable. However, the user can freely select which print setting is the specific print setting.

  FIG. 5 is an explanatory diagram for explaining a reduction in print processing time by the tandem type image forming apparatus according to the present embodiment. The direction of each arrow in FIG. 5 indicates the direction of passage of time. 5A shows the configuration of the print processing time in the master unit and the slave unit of the conventional tandem type image forming apparatus, and FIG. 5B shows the master unit of the tandem type image forming apparatus according to the present embodiment. The structure of the printing process time in a subunit | mobile_unit is shown. Here, the printing processing time in the parent device 40 and the child device 41 refers to the time from when the parent device 40 receives image data until the child device 41 prints the last page of the image data.

  In FIG. 5, the number of pages of image data is 6 pages (odd page 3 pages and even page 3 pages), and the size of image data from the first page to the sixth page is 1 MB, 4 MB, 3 MB in order. It is assumed that 1 MB, 2 MB, and 5 MB. That is, it is assumed that the total amount of even page data size is 10 MB (4 MB + 1 MB + 5 MB), which is larger than the total amount of odd page data size 6 MB (1 MB + 3 MB + 2 MB).

  In FIG. 5, a thin solid line arrow indicates the transfer time of each page of image data from the master unit 40 to the slave unit 41, and a thin broken line arrow indicates the double-sided printing time on the paper. The double-sided printing time is the time required for printing on both sides of a sheet by the master unit 40 and the slave unit 41.

  As shown in FIG. 5A, the conventional tandem type image forming apparatus prints odd-numbered pages including the first page with the master unit and prints even-numbered pages with the slave unit. Accordingly, since even page image data is transferred from the master unit to the slave unit, the total transfer time is 10 seconds when the transfer rate is 1 second / MB. Then, the print processing time is the time obtained by adding the double-sided printing time of the last sheet to 10 seconds as shown by the thick solid line arrow in FIG. 5A.

  On the other hand, the tandem-type image forming apparatus 3 according to the present embodiment transfers the image data having the smaller total data size among the odd pages and the even pages to the child device 41. Therefore, as shown in FIG. 5B, since odd page image data is transferred from the parent device 40 to the child device 41, assuming that the transfer speed is 1 second / MB, the total transfer time is 6 seconds. As a result, the print processing time is 6 seconds plus the double-sided printing time of the last sheet as shown by the thick solid arrow in FIG. 5B.

  Therefore, in the example of FIG. 5, according to the tandem type image forming apparatus 3 according to the present embodiment, the print processing time can be reduced by 4 seconds compared to the conventional tandem type image forming apparatus. Note that the effect of reducing the print processing time becomes more prominent as the total data size of even pages is larger than the total data size of odd pages.

  FIG. 6 is a flowchart of the image forming method according to the present embodiment. This flowchart can be implemented by the tandem type image forming apparatus 3 according to the present embodiment.

  The tandem image forming apparatus 3 receives a print job from the client PCs 2a, 2b, and 2c through the external interface 35 (S601).

  The image control unit 38 determines whether or not specific print settings are included in the print settings of the print job (S602). If the specific print setting is included in the print setting (S602: Yes), the image control unit 38 instructs the master unit to transfer the image data of even pages to the slave unit (S605).

  When the specific print setting is not included in the print setting (S602: No), the image control unit 38 analyzes the total amount of the data sizes of the odd and even pages of the image data (S603). As a result of the analysis, if the data size of the odd page of the image data is larger (S604: Yes), the image control unit 38 instructs the master unit 40 to transfer the image data of the even page to the slave unit 41 ( S605). On the other hand, if the data size of the odd page of the image data is not larger (S604: No), the image control unit 38 instructs the master unit 40 to transfer the image data of the odd page to the slave unit 41 (S606). ).

  If the data size of the odd page and the even page of the image data are the same, the image control unit 38 may instruct the master unit 40 to transfer the image data of the even page to the slave unit 41. Then, it may be instructed to transfer the odd page image data to the slave unit 41.

  In accordance with the instruction from the image control unit 38 in step S605 or step S606, the parent device 40 transfers even page or odd page image data to the child device 41 (S607).

  Double-sided printing is performed by printing on one side of the sheet by the master unit 40 and printing on the other side of the sheet by the slave unit 41 (S608).

  The transfer of image data from the parent device 40 to the child device 41 (S607) and double-sided printing (S608) are repeatedly performed until the printing of all pages of the image data is completed (S609).

  The image forming apparatus and the image forming method according to the first embodiment of the present invention have been described above. However, according to the present embodiment, the total data size of the odd and even pages of the image data generated from the print data is calculated. The image data of the page having the larger total amount is printed by the parent device, and the image data having the smaller total amount is transferred from the parent device to the child device. Thereby, the transfer time of image data from the master unit to the slave unit can be shortened, and the print processing time in the master unit and the slave unit can be reduced.

  Further, when the print setting includes a specific print setting designated by the user, the odd page including the first page is printed by the master unit and the even page is printed by the slave unit. As a result, it is possible to reduce the print processing time while enabling an appropriate print process with print settings according to the user's request.

(Second Embodiment)
An image forming apparatus and an image forming method according to the second embodiment of the present invention will be described in detail.

  In the present embodiment, the printing time of image data by the parent device and the transfer time of image data from the parent device to the child device are analyzed for each sheet. Then, the printing start time of the image data by the parent device is adjusted so that the printing of the image data by the parent device is completed at the time when the transfer of the image data from the parent device to the child device is completed. Since the present embodiment is the same as the first embodiment with respect to other points, redundant description is omitted.

  FIG. 7 shows a transfer time of image data from the parent device to the child device for one sheet, a printing time in the parent device (hereinafter referred to as “parent device printing time”), and a printing time in the child device (hereinafter, “ It is explanatory drawing which shows the relationship of "it calls a subunit | mobile_unit printing time".

  FIG. 7A shows the relationship between the image data transfer time from the parent device to the child device, the parent device printing time, and the child device printing time in the first embodiment. The sum of the master printing time and the slave printing time in A of FIG. 7 corresponds to the duplex printing time in FIG.

  As shown in FIG. 7A, in the first embodiment, after the transfer of the image data from the master unit 40 to the slave unit 41 is completed, the master unit 40 prints on one side of the sheet, and then continues. Thus, the slave unit 41 prints on the other side of the sheet.

  On the other hand, in the image forming apparatus 3 according to the present embodiment, printing on one side of the paper in the base unit 40 is performed, and image data for printing the other side of the paper is transferred from the base unit 40 to the slave unit 41. By starting before completion, the print processing time is further reduced.

  However, as shown in FIG. 7B, when printing is started in the master unit 40 at the same time as the image data is transferred from the master unit 40 to the slave unit 41, the image data from the master unit 40 to the slave unit 41 is transferred. The master printing time ends before the transfer is completed. In such a case, a mechanism for stopping the paper in the master unit 40 is necessary until the transfer of the image data to the slave unit 41 is completed. That is, since a mechanism for stopping the paper in the master unit 40 is required during the pause time indicated by the thick solid arrow in FIG. 7B, the cost is increased. On the other hand, instead of providing the mechanism, a device for buffering paper may be installed, but the cost is still increased.

  Therefore, in the present embodiment, the printing time of image data by the parent device 40 and the transfer time of image data from the parent device 40 to the child device 41 are analyzed for each sheet. Then, as shown in C of FIG. 7, the time when the transfer of image data from the parent device 40 to the child device 41 is completed coincides with the time when the image data printing by the parent device 40 is completed. Starts printing of the paper. Such adjustment of the print start time in the parent device 40 can be performed by providing a paper feed waiting time indicated by a thick solid arrow in FIG. The paper feed waiting time can be obtained by subtracting the printing time of image data by the parent device 40 from the time required for transferring image data from the parent device 40 to the child device 41.

  The image forming apparatus and the image forming method according to the second embodiment of the present invention have been described above. However, according to the present embodiment, the time when image data transfer from the master unit to the slave unit is completed and the image by the master unit are described. Printing of the paper by the master unit is started so that the time for completing the printing of data coincides. Thereby, it is possible to further reduce the printing processing time in the master unit and the slave unit.

  The image forming apparatus and the image forming method according to the present invention are not limited to the above-described embodiments.

  For example, the image data transferred from the parent device to the child device may be image data compressed to further reduce the transfer time.

  Furthermore, in order to unify the orientation of the surface of the printed paper ejected from the image forming apparatus without depending on the size relationship between the total size of the odd-numbered page and even-numbered page of the image data, the image forming apparatus reverses the sheet. Means may be provided.

  Further, in the above-described embodiment, whether or not a specific print setting is included in the print job is determined before analyzing the total data size of each of the odd-numbered pages and even-numbered pages. Or later.

1 image forming system,
2a, 2b, 2c client PC,
3 Tandem type image forming apparatus,
4 network,
31 CPU,
32 RAM,
33 ROM,
34 HDD,
35 External interface,
36 operation unit,
37 display section,
38 Image control unit,
39 Reading section,
40 First engine,
41 Second engine,
42 Post-processing section.

Claims (6)

Receiving means for receiving print data;
Image data generating means for generating image data for printing from the print data received by the receiving means;
Analyzing means for analyzing the total amount of odd page data sizes of the image data generated by the image data generating means, and the total amount of even page data sizes;
The image data analyzed by the analyzing means is transmitted to the first engine, and a sheet is supplied to the first engine based on the image data having a larger total data size analyzed by the analyzing means among odd pages and even pages. The image data having the smaller total data size is transferred from the first engine to the second engine in order to print on one side of the paper and to print on the other side of the paper after printing by the first engine. Control means;
An image forming apparatus comprising: The analysis means further analyzes the print setting of the print data,
When the print setting analyzed by the analysis unit includes a specific print setting designated in advance, the control unit prints the first engine on the one surface of the sheet based on the image data of odd pages. 2. The image forming apparatus according to claim 1, wherein the image data of even-numbered pages is transferred to the second engine in order to print on the other side of the sheet after printing by the first engine. The analysis means further analyzes the printing time of the image data by the first engine and the transfer time of the image data from the first engine to the second engine for each sheet,
The control means, based on the printing time and the transfer time analyzed by the analysis means, for each sheet, when the transfer of the image data from the first engine to the second engine is completed and the first time 3. The image forming apparatus according to claim 1, wherein the first engine starts printing of a sheet so that a time for completing the printing of the image data by one engine coincides. Receiving print data (a);
Generating image data for printing from the print data received in step (a) (b);
Analyzing the total amount of odd page data sizes and the total amount of even page data sizes of the image data generated in step (b);
The image data is transmitted to the first engine. Based on the image data having the larger total data size analyzed in the step (c) among the odd pages and the even pages, the first engine sends the image data to one side of the sheet. (D) transferring the image data having a smaller total data size from the first engine to the second engine for printing and printing on the other side of the sheet after printing by the first engine; ,
An image forming method comprising: The step (c) further analyzes the print setting of the print data,
In the step (d), when the print setting analyzed in the step (c) includes a specific print setting designated in advance, the one of the sheets of paper is sent to the first engine based on the image data of odd pages. 5. The image data of even number pages is transferred to a second engine for printing on the other side of the paper and printing on the other side of the paper after printing by the first engine. Image forming method. The step (c) further analyzes the printing time of the image data by the first engine and the transfer time of the image data from the first engine to the second engine for each sheet,
In the step (d), the transfer of the image data from the first engine to the second engine is completed for each sheet based on the printing time and the transfer time analyzed in the step (c). 6. The image forming method according to claim 4, wherein the first engine is caused to start printing so that the time coincides with a time when the printing of the image data by the first engine is completed. .

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