JP5371800B2 - Image forming system and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption when double-side printing is performed and post processing is performed by a post-processing device, in an image forming system including two interconnected image forming apparatuses. <P>SOLUTION: This image forming system includes first and second image forming apparatuses 100A and 100B, and the first image forming apparatus is located on the upstream side of the discharge direction of a recording sheet. At least the second image forming apparatus has a double-side printing function. When double-side printing is performed, one is selected from first double-side printing control of forming an image on one surface of the recording sheet with the first image forming apparatus and then forming an image on the other surface of the recording sheet with the second image forming apparatus, and second double-side printing control of performing double-side printing on the recording sheet using the second image forming apparatus. In this selection, which of the first and second double-side printing controls is used is determined according to first throughput per unit time including post processing in the post-processing device 500 when the first double-side printing control is performed and second throughput per unit time of the second image forming apparatus. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to an image forming system using a plurality of image forming apparatuses such as copying machines and a control method thereof, and more particularly to an image forming system in which a plurality of image forming apparatuses are connected to each other and a control method thereof .

  In general, an image forming system (hereinafter also referred to as a printing system) in which a plurality of image forming apparatuses are connected to each other to perform printing (printing) on a recording sheet (for example, recording paper) is known (hereinafter also referred to as a printing system). For example, see Patent Document 1).

  In such a printing system, when performing double-sided printing on a recording sheet, an image forming apparatus (hereinafter referred to as an upstream image forming apparatus) located upstream in the discharge direction of the recording sheet is used on one side of the recording sheet (for example, Print on the front side. Further, an image forming apparatus located on the downstream side (hereinafter referred to as a downstream image forming apparatus) prints on the other side (for example, the back side) of the recording sheet to perform double-sided printing.

  As described above, using the printing system in which two image forming apparatuses are connected to each other, the upstream and downstream image forming apparatuses perform printing on one side and the other side of the recording sheet, respectively, thereby performing double-sided printing. By doing so, it is possible to perform the duplex printing process with a single image forming apparatus at a higher speed than when duplex printing is performed.

JP 2006-58881 A

  Incidentally, a post-processing apparatus may be connected to the above-described image forming system in a so-called inline manner. Then, the post-processing device automatically performs post-processing on the printed recording sheet. This post-processing is, for example, stapling, folding, or glued case binding. Thus, if a post-processing device is connected to the image forming system, post-processing can be performed at high speed.

  However, depending on the type of post-processing performed by the post-processing device, the time required for the post-processing may vary greatly. For example, in glued case binding, which is one type of post-processing, processing such as stacking and stacking recording sheets after printing and folding the recording sheets can be performed at high speed, but the glued back It takes a certain amount of time for each bookbinding copy until the glue on the cover is dried.

  When performing glued case binding as described above, the time required for bookbinding greatly depends on the post-processing capability of the post-processing apparatus, no matter how fast double-sided printing is performed on the recording sheet. . That is, the processing capacity per unit time (that is, processing speed) in the image forming system largely depends on the post-processing capacity in the post-processing apparatus, and the processing performance in the post-processing apparatus becomes a bottleneck.

  Therefore, when multi-copy gluing bookbinding is performed in the post-processing device, the post-processing for the second copy is started if the post-processing for the first copy is not completed even if double-sided printing is performed for the second and subsequent copies at high speed. Can not do it. That is, even if double-sided printing of a recording sheet is performed at a high speed in the image forming system, the meaning of performing the double-sided printing at high speed will be reduced in consideration of post-processing. As a result, even if two image forming apparatuses are used, the processing performance is not improved as a result, and the use of two image forming apparatuses increases the power consumption. There is a problem.

Accordingly, in view of the above problems, an object of the present invention is to provide an image forming system capable of reducing power consumption when performing double-sided printing and performing post-processing in a post-processing apparatus, and a control method thereof. There is to do.

In order to achieve the above object, an image forming system according to the present invention includes first and second image forming apparatuses for forming an image on a recording sheet in accordance with image data, and the first and second image forming apparatuses. the image forming apparatus are connected to each other, the first image forming apparatus is positioned on the upstream side of the discharge direction of the recording sheet, before Symbol second image forming apparatus includes a duplex printing function, the second image In an image forming system including a post-processing device that performs post-processing on a recording sheet discharged from a forming device, when performing double-sided printing on the recording sheet, an image is formed on one surface of the recording sheet by the first image forming device. After the formation, the first double-sided printing control for forming an image on the other side of the recording sheet by the second image forming apparatus, and the double-sided printing on the recording sheet using the second image forming apparatus With the second duplex printing control Is intended to select a Zureka, if performing the post-processing by the post-processing device is designated, the first when performing duplex printing control the post the first per unit time including depending on the second processing capacity per unit of the processing capability second image forming apparatus time, to have a print control means to select one of said first and said second double-sided printing control Features.
In order to achieve the above object, a control method according to the present invention includes first and second image forming apparatuses that perform image formation on a recording sheet according to image data, and the first and second image forming apparatuses. Forming apparatuses are connected to each other, the first image forming apparatus is positioned upstream in the discharge direction of the recording sheet, the second image forming apparatus has a duplex printing function, and the second image forming apparatus In a control method for controlling an image forming system provided in a post-processing apparatus that performs post-processing on the recording sheet discharged from the apparatus, image formation is performed on the one surface of the recording sheet by the first image forming apparatus. Then, a first step of executing a first double-sided printing control for forming an image on the other surface of the recording sheet by the second image forming apparatus, and the recording sheet using the second image forming apparatus Image formation on both sides A second step of executing the second double-sided printing control, a first processing capacity per unit time including the post-processing when the first double-sided printing control is performed, and the second image. And a third step of selecting one of the first double-sided printing control and the second double-sided printing control according to the second processing capability per unit time of the forming apparatus. .

According to the present invention, the print control hand stage, if is possible to perform post-processing by the post-processing device is designated, the first per unit time including post-processing at the time of performing the first double-sided printing control According to the processing capability and the second processing capability per unit time of the second image forming apparatus, either one of the first and second duplex printing controls can be selected to perform duplex printing, which is unnecessary. There is an effect that power consumption can be reduced. In addition, if the power consumption is reduced, there is an effect that the life of the parts can be increased and unnecessary noise is reduced.

1 is a partially broken view showing an example of an image forming system in an embodiment of the present invention. It is sectional drawing for demonstrating the post-processing apparatus used with the image forming system shown in FIG. It is a block diagram for demonstrating the control function of the image forming system shown in FIG. 3 is a flowchart for explaining processing in duplex printing in the image forming system shown in FIG. 1. 2 is a flowchart for explaining processing in single-sided printing in the image forming system shown in FIG. 1. 3 is a flowchart for explaining processing in sleep control in the image forming system shown in FIG. 1. FIG. 2 is a diagram illustrating a decision table used in the image forming system illustrated in FIG. 1, and (A) is a diagram illustrating a decision table when performing double-sided printing using the first and second image forming apparatuses; FIG. 10 is a diagram illustrating a decision table when performing duplex printing using the second image forming apparatus.

  Hereinafter, an example of an image forming system according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially broken view showing an example of an image forming system 100 according to an embodiment of the present invention. The illustrated image forming system 100 includes first and second image forming apparatuses 100A and 100B and a post-processing apparatus 500. The first and second image forming apparatuses 100A and 100B are connected in tandem (that is, connected).

  Since the configurations of the first and second image forming apparatuses 100A and 100B are the same, here, the configuration and operation of the first image forming apparatus 100A will be described focusing on the first image forming apparatus 100A.

  In the illustrated example, the first image forming apparatus 100A is an upstream image forming apparatus located on the upstream side in the recording sheet discharge direction. The second image forming apparatus 100B is a downstream image forming apparatus located on the downstream side in the recording sheet discharge direction. A post-processing device 500 that performs post-processing such as bookbinding is disposed at the rear stage (that is, the downstream side) of the second image forming apparatus 100B.

  In the illustrated example, the first and second image forming apparatuses 100A and 100B are image forming apparatuses that can perform color printing. However, the present invention can be applied to an image forming apparatus that only performs monochrome printing. be able to.

  The first image forming apparatus 100A includes a document feeding device 117, an image reader (not shown), and a printer unit 119. The image reader includes a reader scanner unit (not shown) and an image sensor (not shown).

  The document feeder 117 places the documents set on the document setting table 117A one by one from the first page in order, on a platen glass (not shown) through a curved path, from left to right in the figure. The paper is conveyed and discharged to a paper discharge tray 117B.

  The reader scanner unit is held in a predetermined position, and the document passes from the left to the right on the reader scanner unit when being conveyed from left to right in the drawing. As a result, the document is read by the reader scanner unit. That is, when the document passes, light is emitted from the reader scanner unit to the document, and reflected light from the document is guided to the image sensor via the mirror. Alternatively, the original may be read by moving the reader scanner unit from the left to the right in the drawing after stopping the original after the original is fed onto the platen glass by the original feeding device 117.

  The image sensor reads a document and outputs it as image information. This image information is subjected to image processing as necessary, and then sent as image data to the exposure control units 103y, 103m, 103c, and 103k. The subscripts y, m, c, and k correspond to yellow, magenta, cyan, and black, respectively.

  The exposure control units 103y, 103m, 103c, and 103k perform laser light output control according to the image data. The exposure control units 103y, 103m, 103c, and 103k irradiate the photosensitive drums 10y, 10m, 10c, and 10k with laser beams, respectively. Accordingly, electrostatic latent images are formed on the photosensitive drums at 10y, 10m, 10c, and 10k, respectively.

  The electrostatic latent images formed on the photosensitive drums 10y, 10m, 10c, and 10k are developed by the developing units 102y, 102m, 102c, and 102k, respectively, to form toner images. These toner images are sequentially transferred onto the intermediate transfer belt 104 at the primary transfer portions 105y, 105m, 105c, and 105k (primary transfer). As a result, when the original is a color original, a color toner image is formed on the intermediate transfer belt 104.

  Thereafter, the color toner image is transferred onto the recording sheet fed from any one of the recording sheet cassettes (hereinafter simply referred to as cassettes) 109 and 110, the manual sheet feeding unit 111, and the double-sided conveyance path 112. Transferred at 106 (secondary transfer). The recording sheet to which the color toner image has been transferred is sent to the fixing unit 107 where the fixing process is performed.

  The recording sheet that has passed through the fixing unit 107 is once guided to the path 122 by the flapper 121. After the trailing edge of the recording sheet passes through the flapper 121, the recording sheet is switched back and guided to the discharge roller 118 by the flapper 121. As a result, the recording sheet is discharged from the printer unit 119 by the discharge roller 118 in a state where the printed surface faces downward (face down). The developing devices 102y, 102m, 102c, and 102k are supplied with toner from toner replenishing units 101y, 101m, 101c, and 101k, respectively.

  The recording sheet discharged from the first image forming apparatus 100A is sent to the second image forming apparatus 100B. In the first image forming apparatus 100A, printing is performed on one surface (for example, the front surface) of the recording sheet. In the second image forming apparatus 100B, similarly to the first image forming apparatus 100A, printing is performed on the other surface (for example, the back surface) of the recording sheet. Here, both sides of the original are read by the first image forming apparatus 100A. Then, as will be described later, image data indicating an image to be printed on the front surface of the recording sheet is sent to the first image forming apparatus 100A, and image data indicating an image to be printed on the back surface of the recording sheet is a second image. It is sent to the forming apparatus 100B.

  The recording sheet subjected to double-sided printing as described above is sent from the second image forming apparatus 100B to the post-processing apparatus 500. Although not shown, another post-processing device may be further connected to the subsequent stage of the post-processing device 500. The following another post-processing device is referred to as another post-processing device.

  In FIG. 1, the example in which the first image forming apparatus 100A performs printing on one side of the recording sheet and the second image forming apparatus 100B performs printing on the other side of the recording sheet has been described. Each of the second image forming apparatuses 100A and 100B has a duplex printing function. In other words, double-sided printing can be performed on the recording sheet using one of the first and second image forming apparatuses 100A and 100B, but the description thereof is omitted here.

  FIG. 2 is a cross-sectional view for explaining a post-processing apparatus 500 used in the image forming system shown in FIG. In the illustrated example, the post-processing apparatus 500 is a so-called case binding apparatus that performs bookbinding.

  Referring to FIG. 2, the post-processing apparatus 500 includes a paper stacking unit 500A, a gluing unit 500B, an adhesive unit 500C, a cutting unit 500D, and a bookbinding discharge unit 500E.

  The sheet stacking unit 500A receives the recording sheets P and sequentially stacks these recording sheets P to form a sheet bundle (hereinafter referred to as a sheet bundle). Then, the gluing unit 500B performs gluing on the sheet bundle. Further, the bonding unit 500C bonds the glued sheet bundle and the cover. After bonding the cover, the cutting unit 500D cuts the three directions other than the gluing surface in order to align the bookbinding end surfaces. The completed bookbinding is discharged from the bookbinding discharge unit 500E. As will be described later, when the post-processing mode, that is, the bookbinding mode is set, the recording sheet is sent to the paper stacking unit 500A.

  In the post-processing apparatus 500, a conveyance roller pair 505 is provided at an entrance where the recording sheet P is carried in, and a switching flapper 521 is disposed on the downstream side of the conveyance roller pair 505. The switching flapper 521 is for selectively guiding the recording sheet P conveyed by the conveying roller pair 505 to the paper stacking unit 500A or another post-processing apparatus.

  In the illustrated example, when the normal mode is set, the recording sheet P discharged from the second image forming apparatus 100B is conveyed on the conveyance path 600A by the conveyance roller pairs 505, 510, 511, 513, and 514. Then, the paper is discharged to another post-processing apparatus by a paper discharge roller 515.

  This separate post-processing apparatus is, for example, a sheet post-processing apparatus connected as a downstream apparatus of the post-processing apparatus 500. An example of the sheet post-processing apparatus is a finisher, which processes the recording sheets into a bundle. That is, the finisher performs post-processing such as bundle discharge processing, binding processing, folding processing, and bookbinding processing. On the other hand, when the post-processing mode, that is, the bookbinding mode, is set, the recording sheet P discharged from the second image forming apparatus 100B is conveyed on the conveyance path 600B by the conveyance roller pairs 506, 507, and 508. The paper is discharged onto the paper stacking section 500A by the stacking section discharge roller 509. The paper stacking unit 500 </ b> A has a paper stacking tray 520, and the recording sheets P are discharged onto the paper stacking tray 520, where they are aligned to form a sheet bundle 540.

  Here, the bookbinding operation in the post-processing apparatus 500 will be described. Here, only an outline of a series of bookbinding operations will be described, and detailed description thereof will be omitted.

  In the post-processing mode, that is, the bookbinding mode, the sheet stacking unit 500A sequentially receives the recording sheets P and stacks the recording sheets on the sheet stacking tray 520 to form a sheet bundle 540 as described above. The sheet bundle 540 moves from the sheet stacking unit 500A to the gluing unit 500B. The gluing unit 500B includes a glue container 525, a glue application roller 524, and a glue application roller control motor 522. A part of the glue application roller 524 is immersed in the glue container 525, and the glue application roller 524 applies glue to the lower surface of the sheet bundle 540 by driving the glue application roller control motor 522.

  As shown in the drawing, an inserter 300 is provided on the upper portion of the post-processing apparatus 500. The inserter 300 is for supplying a sheet (cover sheet) which is a cover of the sheet bundle 540.

  The inserter 300 feeds the cover sheet positioned at the top of the cover sheet bundle stacked on the paper feed tray 310 by the paper feed roller 301 while the paper bundle 540 is moved to the gluing unit 500B. . The cover sheet is conveyed on the conveyance path 600C by the conveyance roller 302 and the conveyance roller pairs 303, 503, and 504, and is guided to the adhesive portion 500C by the switching flapper 521.

  Thereafter, the glued sheet bundle 540 is adhered to the above-described cover sheet by the adhesive unit 500 </ b> C and delivered to the trim gripper 512 as a booklet 570.

  The booklet 570 is conveyed by the trim gripper 512 to the cutting unit 500D. In the cutting unit 500D, the cutter control motor 527 moves the cutter 528 in the horizontal direction in the drawing to cut the booklet 570. At this time, the cutting waste generated as a result of cutting falls into the waste receiving box 533. When a series of cutting operations is completed, the cutting waste is collected in the waste box 532. When the cutting in the cutting unit 500D is completed, the booklet 570 is conveyed from the cutting unit 500D to the bookbinding discharge unit 500E. Then, the booklet 570 is discharged to the outside by the bookbinding discharge unit 500E.

  FIG. 3 is a block diagram for explaining a control function of the image forming system 100 shown in FIG.

  Referring to FIG. 3, the image forming system 100 includes a main control unit 200 and first and second control units 200A and 200B. In the illustrated example, the main control unit 200 is disposed in the first image forming apparatus 100A, and the main control unit 200 controls the first and second image forming apparatuses 100A and 100B as will be described later. The first and second control units 200A and 200B are disposed in the first and second image forming apparatuses 100A and 100B, respectively.

  The main control unit 200 includes a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, an I / F (Interface) unit 204, and an operation 206. The CPU 201, ROM 202, RAM 203, I / F unit 204, and operation unit 206 are connected to each other via an internal bus 207.

  The first control unit 200A includes a job control unit 211, a recording control unit 212, a recording unit 213, and an I / F unit 214. The job control unit 211, recording control unit 212, and I / F unit 214 are connected to each other via an internal bus 215. Similarly, the second control unit 200B includes a job control unit 221, a recording control unit 222, a recording unit 223, and an I / F unit 224, and the job control unit 221, the recording control unit 222, and the I / F unit 224. The F units 224 are connected to each other via an internal bus 225.

  As shown in the figure, the I / F units 204, 214, and 224 are connected to each other by an external bus 230, whereby the main control unit 200 and the first and second control units 200A and 200B communicate with each other. It can be performed.

  The ROM 202 stores control contents to be executed by the CPU 201 as a control program, and the CPU 201 controls the entire image forming system 100 according to the control program. The RAM 203 is used as a work area necessary when the CPU 201 controls the image forming system 100. In addition to being used as a work area for the CPU 201, the RAM 203 stores, for example, image data obtained by reading a document and image data from the outside of the image forming system 100 (for example, image data from a personal computer). The RAM 203 is also used as a work area when image processing is performed on image data.

  Using the operation unit 206, the user sets a job to be executed on the image forming system 100. That is, the user inputs a job command for instructing the image forming system 100 to execute a job from the operation unit 206. The CPU 201 stores, in the RAM 203, image data obtained by reading the document placed on the document setting table 117A in response to the job command.

  For example, the CPU 201 determines the image information according to the job command such as single-sided printing / double-sided printing command input from the operation unit 206 or according to the content of the image information obtained as a result of reading the original by the original reading unit 118. Necessary image processing is performed on the image data to obtain image data. Then, the CPU 201 stores this image data in the RAM 203. For example, the image forming system 100 can execute a job from the personal computer via the I / F unit 204 without using the operation unit 206.

  The I / F unit 204 is also connected to a network such as TCP / IP, and receives a job command from a computer such as a personal computer connected to the network. Further, the I / F unit 204 can notify various internal information of the image forming system 100 to the computer via the network.

  In the first and second control units 200A and 200B, the I / F units 214 and 224 respectively receive job information from the I / F unit 204 as job information. The job information is sent to job control units 211 and 221, respectively. The job control units 211 and 221 respectively perform job control (that is, job control of the first and second image forming apparatuses 100A and 100B according to the job information (that is, Print control).

  The recording control units 212 and 222 perform recording control for the recording units 213 and 223, respectively. The recording control units 212 and 222 execute the above-described recording control based on instructions from the job control units 211 and 221, respectively. Here, the image data transferred from the main control unit 100 is temporarily stored in the recording units 213 and 223.

  As illustrated, a post-processing device 500 is connected to the job control unit 221. The post-processing device 500 includes a CPU 901, a ROM 902, a RAM 903, and a communication IF unit 907, and the job control unit 221 communicates with the CPU 901 via the communication IF unit 907.

  The ROM 902 stores a control program executed by the CPU 901, and the CPU 901 executes the control program in accordance with a post-processing instruction (that is, a bookbinding instruction in this case) sent from the job control unit 221. Then, the CPU 901 controls the paper stacking unit 500A, the gluing unit 500B, the bonding unit 500C, and the cutting unit 500D as described above. The RAM 903 is used as a work area for the CPU 901.

  FIG. 4 is a flowchart for explaining processing in duplex printing in the image forming system 100 shown in FIG.

  With reference to FIGS. 1, 2, and 4, the CPU 201 of the main control unit 200 executes control related to the illustrated double-sided printing process. When performing duplex printing, a document is set on one of the document setting tables 117A of the first and second image forming apparatuses 100A and 100B.

  In the example shown in the figure, for example, it is assumed that a document is set on the document setting table 117A of the first image forming apparatus 100A. Then, both sides of the original are read by the reader scanner unit, and temporarily stored in the RAM 203 as image data as described above.

  First, the main control unit 200 sequentially prints image data to be printed on one surface (for example, the front surface) of the recording sheet, among the image data stored in the RAM 203, to the first image forming apparatus 100A, that is, the first control. The data is transferred to the unit 200A (step S31). The image data is temporarily stored in the recording unit 213 as described above. Similarly, the CPU 201 sequentially transfers image data to be printed on the other side (for example, the back side) of the recording sheet to the second image forming apparatus 100B, that is, the second control unit 200B (step S32). The image data is temporarily stored in the recording unit 223 as described above.

  The CPU 201 sends a paper feed command to the first control unit 200A (that is, the job control unit 211) (step S33). Accordingly, the job control unit 211 feeds a recording sheet from the cassette 109 or 110 of the first image forming apparatus 100A, for example. Subsequently, the CPU 201 sends an image formation command to the first control unit 200A (that is, the job control unit 211) (step S34). That is, the CPU 201 instructs the job control unit 211 to form, develop, transfer, and fix an electrostatic latent image. As a result, in the first image forming apparatus 100A, the job control unit 211 controls the recording control unit 212, and on the surface of the recording sheet as described above according to the image data recorded in the recording unit 213. Perform image formation.

  Next, the CPU 201 sends a recording sheet inversion instruction to the first control unit 200A (that is, the job control unit 211) (step S35). Accordingly, after the toner image is fixed on the recording sheet under the control of the job control unit 211, the recording sheet is conveyed to the reversing path 122 in the first image forming apparatus 100A. The recording sheet is reversed in the reversing path 122 and fed to the paper discharge roller 118.

  Then, the recording sheet is discharged out of the first image forming apparatus 100A by the discharge roller 118. Here, the recording sheet is sent from the paper discharge roller 118 to the second image forming apparatus 100B.

  The recording sheet discharged from the first image forming apparatus 100A is sent to the paper feeding unit 111 of the second image forming apparatus 100B, and from there, is fed into the second image forming apparatus 100B.

  In the second image forming apparatus 100B, printing is performed on the back surface of the recording sheet in the same processing procedure as that of the first image forming apparatus 100A. The CPU 201 sends an image formation command to the second control unit 200B (that is, the job control unit 221) and executes image formation control.

  As a result, a toner image is formed on the back surface of the recording sheet. Then, after fixing the toner image, the recording sheet is not reversed, and the recording sheet is discharged to the outside by the paper discharge roller 118 of the second image forming apparatus 100B (second image forming apparatus control: step S36). . Then, the main control unit 200 ends the double-sided printing process.

  As described above, when post-processing by the post-processing device 500 arranged at the subsequent stage of the second image forming apparatus 100B is designated, the post-processing device 500 subsequently performs bookbinding and the like. Processing is performed to complete the printed matter.

  FIG. 5 is a flowchart for explaining processing in single-sided printing in the image forming system 100 shown in FIG.

  With reference to FIGS. 1, 2, and 5, the CPU 201 of the main control unit 200 executes control related to the illustrated single-sided printing process. When performing single-sided printing, a document is set on one of the document setting tables 117A of the first and second image forming apparatuses 100A and 100B.

  In the example shown in the figure, for example, it is assumed that a document is set on the document setting stand 117A of the second image forming apparatus 100B. Then, the image on one side of the document is read by the reader scanner unit and temporarily stored in the RAM 203 as image data as described above.

  In the single-sided printing process, one of the first and second image forming apparatuses 100A and 100B is used. Here, the second image forming apparatus 100B, that is, the downstream side is used. An image forming apparatus is used. This is because even when the first image forming apparatus 100A, that is, the upstream image forming apparatus is in the sleep state, only the second image forming apparatus 100B can form an image and pass a recording sheet. Conversely, if single-sided printing processing is performed using the first image forming apparatus 100A, the second image forming apparatus 100B must also be operated in order to convey the recording sheet, increasing power consumption and component life. Decrease occurs.

  For this reason, the main control unit 200 uses the second image forming apparatus 100B regardless of whether or not the original is set on one of the first and second image forming apparatuses 100A and 100B. To execute image formation.

  First, the CPU 201 of the main control unit 200 sequentially transfers the image data stored in the RAM 203 to the second image forming apparatus 100B, that is, the second control unit 200B (step S41). Next, the CPU 201 sends a paper feed command to the second control unit 200B (that is, the job control unit 221) (step S42). As a result, the job control unit 221 feeds a recording sheet from the cassette 109 or 110 of the second image forming apparatus 100B, for example.

  Subsequently, the CPU 201 sends an image formation command to the second control unit 200B (that is, the job control unit 211) (step S43). That is, the CPU 201 instructs the job control unit 211 to form, develop, transfer, and fix an electrostatic latent image.

  In the second image forming apparatus 100B, the job control unit 221 controls the recording control unit 222 to form an image on the surface of the recording sheet as described above according to the image data recorded in the recording unit 223. I do. After the toner image is fixed on the recording sheet, the recording sheet is fed to the paper discharge roller 118 in the second image forming apparatus 100B. The recording sheet is discharged out of the second image forming apparatus 100B by the paper discharge roller 118. When post-processing by the post-processing apparatus 500 is designated, as described above, post-processing such as bookbinding is performed by the post-processing apparatus 500 to complete a printed matter. Then, the CPU 201 ends the single-sided printing process.

  Next, sleep control in the image forming system shown in FIG. 1 will be described. Each of the first and second image forming apparatuses 100 </ b> A and 100 </ b> B, for example, supplies current to a stepping motor (not shown) and adjusts the temperature of the fixing unit during image formation or in a standby state. . For this reason, it is the state which is consuming electric power.

  On the other hand, in the sleep state where the power consumption state is lower than that in the standby state, only the job control units 211 and 221 shown in FIG. 2 are energized. In the sleep state, power consumption is reduced by stopping energization of loads such as motors and heaters. Control in the sleep state is executed by an instruction from the CPU 201. That is, the CPU 201 gives a sleep command to the job control unit 211 or 221, and the job control units 211 and 221 control the energization states in the first and second image forming apparatuses 100 </ b> A and 100 </ b> B, respectively, according to the sleep command. .

  If the user performs an operation for shifting to the sleep state from the operation unit 206, the CPU 201 selectively places the first and second image forming apparatuses 100A and 100B in the sleep state in accordance with this operation. That is, both the first and second image forming apparatuses 100A and 100B can be put into a sleep state, and either one of the first and second image forming apparatuses 100A and 100B can be put into a sleep state.

  Further, when the user sets the sleep transition start time from the operation unit 206, the CPU 201 determines that the designated image forming apparatus has elapsed when the time specified by the sleep transition start time has elapsed from the standby state according to the count of the built-in timer. Is automatically shifted to the sleep state.

  When the sleep transition operation and the sleep transition start time are set, the CPU 201 sleeps with respect to both or one of the first and second control units 200A and 200B via the I / F unit 204. Issue a transition command. As a result, the corresponding image shaping device transitions to the sleep state.

  As described above, when printing is not performed, the CPU 201 uses the first and second image forming apparatuses 100A and 100B in a standby state in which printing can be started immediately, and at least consumes less power than the standby state. It is selectively controlled to either a low sleep state.

  Next, the return from the sleep state to the standby state will be described. In the image forming system 100 shown in FIG. 1, when shifting (returning) from the sleep state to the standby state, in the first and second image forming apparatuses 100A and 100B, the initial position of a control motor (not shown) is determined. Need to do.

  Furthermore, it is necessary to set the initial state for the first and second control units 200A and 200B and to set the temperature of the fixing unit to the standby temperature. Of these, the maximum time required to adjust the temperature of the fixing unit to the standby temperature is about 3 minutes. That is, when energization is started in a state where the fixing unit is cold, it takes a maximum of 3 minutes to return from the sleep state to the printable standby state. When the transition from the standby state to the sleep state is made after printing, depending on the subsequent time, if the temperature of the fixing unit is somewhat high, the sleep state can be returned to the standby state in a shorter time. When returning from the sleep state to the standby state, the CPU 201 issues a sleep return command to the first and second control units 200A and 200B via the I / F unit 231 respectively.

  Here, sleep control when performing double-sided printing in the illustrated image forming system 100 and then performing post-processing using the post-processing device 500 will be described. Here, a case where a plurality of copies are printed will be described.

  FIG. 6 is a flowchart for explaining processing in the sleep control in the image forming system 100 shown in FIG. FIG. 7 is a diagram showing a decision table used in the image forming system 100 shown in FIG. (A) is a diagram showing a decision table representing the state of the first and second image forming apparatuses when performing duplex printing using the first and second image forming apparatuses 100A and 100B. (B) is a diagram showing a decision table representing the states of the first and second image forming apparatuses when performing double-sided printing using the second image forming apparatus 100B.

  With reference to FIG. 1, FIG. 2, FIG. 6, and FIG. 7, this sleep control process is executed in CPU 201 of main control unit 200 shown in FIG. The ROM 202 is set with the decision tables (decision tables) shown in FIGS. 7A and 7B, and the CPU 201 refers to these decision tables during the sleep control process.

  First, the CPU 201 analyzes the contents of the print job input to the image forming system and obtains an analysis result (step S501). It is assumed that this analysis result includes at least the paper size, the double-sided printing process, and the single-sided printing process. On the other hand, the ROM 202 stores the processing capacity (that is, the processing speed) per unit time according to the paper size, single-sided printing, and double-sided printing as productivity data.

  The CPU 201 reads productivity data corresponding to the analysis result from the ROM 202 (step S502). Subsequently, the CPU 201 determines whether or not post-processing designation (that is, bookbinding designation here) is set (step S503). If post-processing designation is not set (NO in step S503), the CPU 201 executes duplex printing (first duplex printing control) using the first and second image forming apparatuses 100A and 100B (step S503). S508).

  In step S508, the CPU 201 performs sleep control (first control) for the first and second image forming apparatuses 100A and 100B based on the decision table (hereinafter referred to as the first decision table) shown in FIG. Execute sleep control. In the first sleep control, the CPU 201 refers to the first decision table, and when both the first and second image forming apparatuses 100A and 100B are in the sleep state, the first and second image forming apparatuses. Both 100A and 100B execute a return process for returning to the standby state. Thereafter, as described above, the CPU 201 transfers the image data to be printed on the front side of the recording sheet to the first control unit 200A, and transfers the image data to be printed on the back side of the recording sheet to the second control unit 200B. To do.

  When only the first image forming apparatus 100A is in the sleep state, the CPU 201 executes a return process for returning the first image forming apparatus 100A to the standby state. Thereafter, the CPU 201 transfers the above-described image data. When only the second image forming apparatus 100B is in the sleep state, the CPU 201 executes a return process for returning the second image forming apparatus 100B to the standby state. Thereafter, the CPU 201 transfers the above-described image data. If both the first and second image forming apparatuses 100A and 100B are in the standby state, the CPU 201 keeps the first and second image forming apparatuses in the standby state (no change).

  If post-processing designation is set (YES in step S503), the CPU 201 determines whether or not double-sided printing to be executed is the first one (step S504). If it is the first part (YES in step S504), the CPU 201 moves to step S508 because the post-processing time in the post-processing device 500 is not limited, and the first and second image forming apparatuses. According to the state, the first sleep control is performed to execute double-sided printing.

  Then, the CPU 201 determines whether or not the second and subsequent duplex printing is performed by both the first and second image forming apparatuses 100A and 100B or one of them (post-processing apparatus). The time required for 500 including the post-processing time is measured as a part of the elapsed time (step S509), and the process returns to step S501.

  On the other hand, if the double-sided printing to be executed is not the first part (NO in step S504), the CPU 201 obtains the time productivity T based on the first part elapsed time (step S505). This time productivity T represents the processing capacity (first processing capacity) from the start of printing to the end of post-processing. For example, the time productivity T is calculated as the time taken to process the first sheet bundle divided by the number of pages. Is done. As a result, the processing capability (that is, the number of processed pages per unit time) in consideration of the post-processing device 500 is obtained.

  Subsequently, the CPU 201 determines whether or not the time productivity T is smaller than the processing capability (second processing capability, that is, the number of pages processed per unit time) of the second image forming apparatus 100B. (Step S506).

  If the time productivity T is equal to or greater than the processing capability of the second image forming apparatus 100B (greater than or equal to the second processing capability) (NO in step S506), the second image forming apparatus 100B alone has the image forming system. 100 productivity cannot be maximized. Accordingly, the CPU 201 proceeds to step S508 and executes the double-sided processing using the first and second image forming apparatuses 100A and 100B.

  When the time productivity T is smaller than the processing capability of the second image forming apparatus 100B (YES in step S506), the productivity of the image forming system 100 can be obtained using only the second image forming apparatus 100B. Will not change. Accordingly, the CPU 201 executes duplex printing (second duplex printing control) using only the second image forming apparatus 100B (step S507). That is, double-sided printing is performed using only the second image forming apparatus 100B, which is the downstream image forming apparatus.

  In step S507, the CPU 201 performs sleep control (second control) of the first and second image forming apparatuses 100A and 100B based on the decision table (hereinafter referred to as the second decision table) shown in FIG. Execute sleep control.

  In the second sleep control, the CPU 201 refers to the second decision table, and if both the first and second image forming apparatuses 100A and 100B are in the sleep state, only the second image forming apparatus 100B is used. A return process for returning to the standby state is executed. Thereafter, the CPU 201 transfers image data to be printed on the front and back surfaces of the recording sheet to the second control unit 200B, and executes double-sided printing. When only the first image forming apparatus 100A is in the sleep state, the CPU 201 does not execute the return control of the first image forming apparatus 100A (no change) because the second image forming apparatus 100B is used. Thereafter, the CPU 201 transfers the above-described image data. When only the second image forming apparatus 100B is in the sleep state, the CPU 201 executes a return process for returning the second image forming apparatus 100B to the standby state. Further, the CPU 201 executes a transition process for causing the first image forming apparatus 100A to transition to the sleep state. Thereafter, the CPU 201 transfers the above-described image data. When both the first and second image forming apparatuses 100A and 100B are in the standby state, the CPU 201 executes a transition process that causes only the first image forming apparatus 100A to transition to the sleep state. Thereafter, the CPU 201 transfers the above-described image data.

  As described above, in the above embodiment, in the image forming system 100 including the first and second image forming apparatuses 100A and 100B, double-sided printing is performed and post-processing such as bookbinding is performed in the post-processing apparatus. Whether to perform duplex printing using both the first and second image forming apparatuses 100A and 100B or to perform duplex printing using only one of them is determined according to the productivity of the image forming system. become. Therefore, it is possible to determine the number of image forming apparatuses to be used by performing sleep control in consideration of the time required for post-processing, and as a result, it is possible to reduce power consumption.

  Furthermore, if the sleep control as described above is performed to reduce the power consumption, the energization time is reduced, and the life of the parts can be increased. If only the second image forming apparatus 100B is driven, the generation of unnecessary noise is reduced.

  As is clear from the above description, the main control unit 200, that is, the CPU 201 functions as a print control selection unit and a print control determination unit. When performing double-sided printing on the recording sheet, the CPU 201 forms an image on one side of the recording sheet with the first image forming apparatus 100A, and then uses the second image forming apparatus 100B on the other side of the recording sheet. One of the first double-sided printing control for performing image formation and the second double-sided printing control for performing double-sided printing on the recording sheet using the second image forming apparatus 100B is selected. In this selection, the first processing capability per unit time including the post-processing when the first double-sided printing control is performed and the second processing unit per second unit time of the second image forming apparatus 100B. Which one of the first and second double-sided printing controls is used is determined according to the processing capability.

  The CPU 201 functions as a state selection unit. Then, the CPU 201 selects the first and second image forming apparatuses 100A and 100B as one of a standby state in which printing can be started immediately and a sleep state in which power consumption is at least lower than the standby state. Will do.

  Further, when the CPU 201 determines to use the second double-sided printing control, the CPU 201 sets the first image forming apparatus 100A to the sleep state and the second image forming apparatus 100B to the standby state. On the other hand, when the CPU 201 determines to use the first double-sided printing control, the first and second image forming apparatuses 100A and 100B are set in a standby state.

  In the above embodiment, each of the first and second image forming apparatuses 100A and 100B has a duplex printing function. However, at least the second image forming apparatus 100B has a duplex printing function. Then, each control according to the above-described embodiment can be executed.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to these embodiment, Various forms of the range which does not deviate from the summary of this invention are also contained in this invention. .

  For example, the first and second image forming apparatuses 100A and 100B may be controlled by causing the main control unit 200 to execute the control method using the function of the above-described embodiment as a control method. In this case, the control method has the functions of the above-described embodiment as the first step, the second step, and the third step.

  In addition, a computer that controls the first and second image forming apparatuses may be arranged to cause the computer to execute a program having the functions of the above-described embodiments as a control program. Furthermore, the control program may be read from a recording medium storing the control program and executed.

  As a recording medium for supplying the control program, for example, a magnetic recording medium such as a hard disk or a magnetic tape, an optical / magneto-optical storage medium, or a nonvolatile semiconductor memory is used. Further, when supplying the control program, the program may be stored in a server on a computer network, and the client computer may download the program.

100A First image forming apparatus 100B Second image forming apparatus 200 Main control unit 201 CPU
200A 1st control part 200B 2nd control part 211,221 Job control part

Claims (7)

First and second image forming apparatuses for forming an image on a recording sheet according to image data, and the first and second image forming apparatuses are connected to each other to form the first image forming apparatus. after the device is positioned on the upstream side of the discharge direction of the recording sheet, before Symbol comprises second image forming apparatus for double-sided printing function, performs post-processing on the discharged recording sheet from said second image forming apparatus In an image forming system including a processing device,
When performing double-sided printing on the recording sheet, the first image forming apparatus forms an image on one side of the recording sheet, and then the second image forming apparatus forms an image on the other side of the recording sheet. One of a first double-sided printing control and a second double-sided printing control for performing double-sided printing on a recording sheet using the second image forming apparatus is selected , and post-processing by the post-processing apparatus is performed. When it is specified that the first image processing apparatus performs the first double-sided printing control, the first processing capability per unit time including the post-processing and the second per unit time of the second image forming apparatus. depending on the processing power, the image forming system characterized by having a print control means to select one of said first and said second double-sided printing control.   In the printing control means, the first processing capability per unit time including the post-processing when the first double-sided printing control is performed is the second processing capability per unit time of the second image forming apparatus. The second double-sided printing control is selected when the first processing capacity is lower, and the first double-sided printing control is selected when the first processing capacity is higher than the second processing capacity. The image forming system according to claim 1. State selection means for selecting the first image forming apparatus and the second image forming apparatus between a standby state in which printing can be started immediately and a sleep state in which power consumption is lower than the standby state. ,
When the first double-sided printing control is selected, the printing control unit controls the state selecting unit to place the first and second image forming apparatuses in the standby state, and the second double-sided printing. 2. The control apparatus according to claim 1, wherein when the control is selected , the state selection unit is controlled to set the first image forming apparatus to the sleep state and the second image forming apparatus to the standby state. 3. The image forming system according to 2.   The print control unit executes the first double-sided print control when it is not designated to perform post-processing by the post-processing device. Image forming system.   When it is designated to perform post-processing by the post-processing apparatus, the print control unit selects the first double-sided printing control for the first printing, and the first printing for the second and subsequent copies. 2. The method according to claim 1, wherein one of the first and second duplex printing controls is selected based on the first processing capability and the second processing capability based on a processing time of a part. 5. The image forming system according to any one of 4 above.   6. The value obtained by dividing the time required from the start of printing of the first portion to the end of post-processing of the first portion by the number of pages of the first portion is determined as the first processing capability. Image forming system. First and second image forming apparatuses for forming an image on a recording sheet according to image data, and the first and second image forming apparatuses are connected to each other to form the first image forming apparatus. device located upstream side of the discharge direction of the recording sheet, before Symbol a second image forming apparatus duplex printing function, the post-processing on the recording sheet discharged from said second image forming apparatus In a control method for controlling an image forming system provided in a post-processing apparatus to perform,
After image formation in the previous SL said first image forming apparatus on one side of the recording sheet, to execute the first double-sided printing control for performing image formation by the second image forming apparatus on the other side of the recording sheet A first step;
A second step of executing a second double-sided printing control for forming an image on both sides of the recording sheet using the second image forming apparatus;
In accordance with the first processing capability per unit time including the post-processing when the first double-sided printing control is performed and the second processing capability per unit time of the second image forming apparatus. And a third step of selecting one of the first double-sided printing control and the second double-sided printing control .

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