JP4687434B2 - Image forming system and image forming method - Google Patents

Description

  The present invention relates to an image forming system and an image forming method, and more particularly to an image forming system in which an accessory device is connected to an image forming apparatus and job reservation registration is possible.

  The conventional auxiliary device connected to the image forming apparatus can start work immediately upon receiving a work command signal. Recently, however, electrophotographic image forming apparatuses have come to be used in the field of light printing such as POD (Print, on, Demand). A linked image forming system has been developed (Patent Document 1). However, in the bookbinding apparatus, work is started after receiving a work command signal to warm up the glue used for bundling a plurality of sheets. It takes preparation time until it is possible.

  In an image forming system in which a plurality of image forming apparatuses are connected or an image forming system in which an accessory device such as a post-processing device is connected to an image forming apparatus, depending on the communication between the apparatuses and the job execution status in each apparatus, There is a problem in that productivity is reduced due to a situation in which work in the apparatus is interrupted.

  A normal electrophotographic image forming apparatus requires a waiting time of about several minutes from its start-up until it reaches a work start ready state. Therefore, in an image forming system composed of a master unit and a slave unit, when an image formation command is issued from the master unit to the slave unit, if the slave unit is not ready to start work, the slave unit starts work. The preparation time for preparing the possible state becomes a waiting time.

As a method for solving the problem of productivity reduction due to such a waiting time, Patent Document 2 proposes to use a communication time for transmitting image data between apparatuses as a preparation time for a slave unit.
JP 2002-370469 A JP 2004-237468 A

  As described above, in the bookbinding apparatus, a preparation time is required from the time when the work command signal is received until a workable state is reached. Decrease is a problem.

  In an image forming system in which a plurality of image forming apparatuses are connected, it is possible for a plurality of image forming apparatuses to perform image formation in parallel, but in the image forming system in which an accessory device is connected to the image forming apparatus. The relationship between the image forming apparatus and the accessory device is not parallel processing but sequential processing, such that the accessory device receives the paper on which the image is formed in the image forming device and performs post-processing.

  In an image forming system that performs parallel processing, use of communication time as preparation time is effective as a means for preventing productivity from being reduced due to preparation time, as in Patent Document 2, but sequentially. In an image forming system that performs processing, productivity is hardly improved even if communication time is used as preparation time.

  Accordingly, the present invention solves the problem of productivity reduction due to the preparation time of an accessory device in an image forming system equipped with an accessory device that sequentially performs processing in relation to the image forming device such as a post-processing device. Objective.

The object is achieved by the following invention.
1.
Image forming apparatus for forming an image on a sheet, an image forming system having a job control means for controlling the accessory device and the image forming equipment is connected to the image forming apparatus, a plurality of jobs are registerable, continuously registered job in executable images forming system,
It said job control means, wherein after the first job prior not required before the output time quasi備時between the job attachment device, first requires a preparation time of the accessory device in front of the output time of the job when executing the second job, in parallel to prepare for the accessory device for the second job during the output of the preceding first job run, the prior SL until the output of the first job is completed as preparation of the accessory device for second job is completed, and exits the preparation start command of the accessory device for the second job during the output time of the first job, and ends the output of the first job An image forming system starting output of the second job later .
2.
2. The image forming system according to 1, wherein the attachment device includes a heater, and the preparation time is a warm-up time by the heater.
3.
3. The image forming system according to 2 above, wherein the attachment device includes a bookbinding device including a gluing unit that uses a glue that is heated and melted by the heater and binds paper.
4).
4. The image forming system according to item 3, further comprising: a temperature sensor that detects the temperature of the glue, wherein the job control unit performs temperature management of the glue based on a temperature detected by the temperature sensor.
5.
The bookbinding apparatus can be set to a warmed-up state in which the glue is applied and maintained at a melting temperature, and a low power state in which the glue is maintained at a temperature lower than the melting temperature. -Comparing the warm-up time required for shifting from the power state to the warm-up completed state with the remaining time until the first job is completed, and determining the timing of issuing the preparation start command based on the comparison result 5. The image forming system according to 3 or 4, wherein the image forming system is determined.
6).
The job control means compares the output time of the first job with the warm-up time, and determines whether or not the warm-up completed state can be canceled based on the comparison result. Image forming system.
7).
In an image forming method for continuously executing a plurality of registered jobs,
After the preceding first job that does not require a previous job output time preparation time for post-processing, executes the second job that requires a preparation time for post-processing before output time of the job If, compared with the preparation time for post-processing of the output time and the second job to the output of the first job is completed, based on the comparison result, wherein during the output time of the first job An image forming method comprising: starting preparation for post-processing of a second job, and starting output of the second job after finishing output of the first job .
8).
8. The image forming method according to claim 7, wherein the second job is a bookbinding process for binding sheets by gluing, and the preparation time is a warm-up time for heating the glue to a melting temperature.
9.
When the post-processing apparatus is in the warm-up completed state, the output time of the first job is compared with the preparation time, and it is determined whether the warm-up completed state can be canceled based on the comparison result. 9. The image forming method as described in 7 or 8 above.

  According to the present invention, since the preparation of the second job is started during the execution of the first job before the second job requiring the preparation time, the processing is continuously executed from the first job to the second job. It is possible to improve productivity when processing a plurality of jobs.

  The present invention will be described below with reference to the illustrated embodiments, but the present invention is not limited to these embodiments.

[Image forming system]
FIG. 1 is a diagram showing an image forming system according to an embodiment of the present invention, which includes a bookbinding apparatus B as a post-processing apparatus which is an example of an image forming apparatus A and an accessory apparatus.

  An image forming unit A1 of the image forming apparatus A includes a charging unit 2, an image exposing unit (writing unit) 3, a developing unit 4, a transfer unit 5A, a charge removing unit 5B, a separation claw 5C, and the like around a rotating photoreceptor 1. A cleaning unit 6 is provided. After the charging unit 2 uniformly charges the surface of the photoreceptor 1, exposure scanning based on image data read from the document is performed by the laser beam of the image exposure unit 3 to form a latent image. Then, the latent image is reversely developed by the developing means 4 to form a toner image on the surface of the photoreceptor 1.

  On the other hand, the paper S fed from the paper storage means 7A is sent to the transfer position. The toner image is transferred onto the paper S by the transfer means 5A at the transfer position. Thereafter, the charge on the back surface of the sheet S is erased by the charge removing unit 5B, separated from the photosensitive member 1 by the separation claw 5C, conveyed by the intermediate conveyance unit 7B, and subsequently heated and fixed by the fixing unit 8, and then by the sheet discharge roller 7C Discharged.

  When image formation is performed on both sides of the sheet S, the sheet S subjected to the fixing process by the fixing unit 8 is branched from the normal sheet discharge path by the conveyance path switching plate 7D, and is switched back in the reverse conveyance 7E. After the reversal, the sheet is conveyed again to the transfer position, and is discharged out of the apparatus by the discharge roller 7C after the transfer / fixing. The paper S discharged from the paper discharge roller 7C is sent to the receiving unit 11 of the bookbinding apparatus B.

  The developer remaining on the surface of the photoreceptor 1 after the image processing is removed downstream of the separation claw 5C by the cleaning unit 6 to prepare for the next image formation.

  Above the image forming unit A1, an image reading device A2 having an automatic document feeder of the document moving type reading system is installed.

[Bookbinding device]
The bookbinding apparatus B includes a fixed discharge tray 10 at the uppermost stage, a horizontal conveying means 20 below it, a direction changing and conveying means 30, a paper storage section 40, a discharging means 50, a paper discharging section 60, a front cover paper feeding means 70A, and a back surface. The sheet feeding device includes a cover sheet feeding unit 70B, a gluing unit 80, and a glue feeding unit 81.

  In the non-processing mode, the paper S is discharged to the fixed paper discharge tray 10 or the lift paper discharge tray 61 of the paper discharge unit 60.

  In the bookbinding mode, the sheet S is transported from the horizontal transport unit 20 to the direction changing transport unit 30, and after the direction is changed downward along the front wall of the apparatus by the direction changing transport unit 30 as shown in FIG. The paper is stored in the paper storage unit 40. In the paper storage unit 40, a number of sheets S forming a book are stacked.

  Further, the cover sheet K is supplied from the front cover supply unit 70A and the back cover supply unit 70B, and is conveyed by the horizontal conveyance unit 2 and the direction changing conveyance unit 30 and stored in the sheet storage unit 40.

  Each time the sheet S is stored in the sheet storage unit 40, glue is applied to the edge thereof by the applying unit 80, and a plurality of sheets S are bundled on the sheet storage unit 40.

The bundled sheets S and cover sheet K are discharged to the lifting / lowering tray 61 of the sheet discharge unit 60.
[Data processing / control]
FIG. 3 shows data processing such as image data processing and control. It is a block diagram of a control system.

  The scanner unit 120 includes a CCD 121 that reads a document and a scanner control unit 122, and generates image data.

  The ADF control unit 130 performs document conveyance control in the document conveyance device.

  The operation unit 140 includes an LCD 141 that performs display, and an operation unit control unit 142 that performs output control of the LCD and input control from a keyboard and a touch panel.

  The state management unit 100 performs a reading processing unit 101 that processes image data from the scanner unit 120, a scanner unit 120, an ADF control unit 13, an image control CPU 102 that controls the operation unit 140, and writing / reading control of image data. It has a DRAM control IC, a program memory 104, a system memory 105, a nonvolatile memory 106, a write processing unit 108, a compression / decompression IC 109, and an interface 110.

  The printer unit 150 includes a laser diode 151 that exposes the photosensitive member and a printer control unit 152 that performs image formation control such as exposure and development.

  Image data generated by the scanner unit 120 by reading a document or image data received from the outside via the interface 110 is compressed by a compression / decompression IC and stored in the image memory 107.

  In image formation, image data read from the image memory 107 is decompressed by a compression / decompression IC and then processed by the writing control unit 108 to drive the laser diode 151 to form an image on a sheet. Is done.

The bookbinding apparatus B includes a post-processing control unit 201, a heater 202, and a temperature sensor 203 that detects the temperature of the glue. The heater 202 and the temperature sensor 203 are provided in the glue supply device 81 in FIG.
The image forming system shown in FIGS. 1 and 3 operates in various modes. In the bookbinding mode, after the image forming apparatus A forms an image on the paper S, the image-formed paper S is bound to the bookbinding apparatus B one by one. And bookbinding is performed by binding the sheets S in the bookbinding apparatus B. Further, bookbinding is performed by adding a cover K to the paper S as required.

  The image forming apparatus A has a function of reserving and registering a plurality of jobs, and continuously processing the registered jobs in the order set at the time of registration. Such job reservations are stored in the system memory 105.

  FIG. 4 shows a setting screen of the operation unit.

  A job is reserved by setting print conditions, reading and registering a document using the screen of FIG. The job is reserved and registered by pressing the “vacant JOB” tag 301 in FIG.

  Table 1 shows the job data.

Image data accompanied by page data is stored in the system memory 105 and the image memory 107, and the image control CPU 102 as job control means executes a job with reference to various condition items shown in Table 1. As indicated by diagonal lines in Table 1, the job data includes a bookbinding item. In the bookbinding mode, bookbinding “A” is registered. The bookbinding mode is set by pressing a “bookbinding” button 302 in FIG. 4B and a “OK” button 303.
[Job control related to bookbinding]
The glue supply means 81 (shown in FIG. 1) contains glue made of hot melt adhesive, and a plurality of sheets are obtained by applying glue on the back of a bundle of recording paper using glue melted by heating. This recording sheet is bound.

  The bookbinding apparatus B can set the glue in the glue supply means 81 to a normal temperature state when the power is turned off, a warmed-up state in a molten state, and a low power state.

  Of course, the heater 202 is turned off in the normal temperature state, but in the low power state, the paste is heated so as to maintain a temperature higher than the normal temperature but lower than that in the warm-up state. In the warmed-up state, power is supplied to the heater 202 so that the paste can be melted and applied.

  The post-processing control unit 201 performs control for maintaining the paste temperature in the low power state and the warm-up completed state based on the temperature detected by the temperature sensor 203 provided in the paste supply unit 81.

  The temperature control for controlling the bookbinding apparatus B to the low power state and the warm-up state will be described with reference to the flowchart of FIG.

  In STEP 1, it is determined whether or not bookbinding is in progress, and if not in bookbinding, it is determined whether or not it is in a low power state (STEP 2).

  When in the low power state (YES in STEP 2), the presence or absence of a warm-up request from the state management unit 100 is checked (STEP 3). When there is a warm-up request, warm-up is started (STEP 4).

  If it is determined in STEP2 that the power supply is not in the low power state (NO in STEP2), it is checked whether there is a request for transition from the state management unit 100 to low power (STEP5).

  In STEP 5, when there is a request for shifting to low power, shifting to low power (STEP 6).

  In STEP5, when there is no low power request, when the predetermined time Tk is completed after the bookbinding is completed (YES in STEP7), the process shifts to the low power state (STEP6).

  In the status indicated by D, that is, the status after STEPs 4, 6 and 7, the glue supply means 81 is at a temperature between low power and warmed up. During the transition to the up state, that is, during the warm-up, and during the cooling during the transition from the warm-up state to the low power state.

  In STEP 10, it is determined whether or not the warm-up is completed from the low power state, and when the warm-up is completed, the state management unit 100 is notified of the warm-up completion (STEP 11).

  On the other hand, when the warm-up is not completed from the low power (NO in STEP 10), and when the warm-up has been completed and the power has shifted to the low power (YES in STEP 12), the low power state is notified to the image forming apparatus main body. To do.

  When the warm-up is not completed from the low power (NO in STEP 10), and when the warm-up has not been switched to the low power (NO in STEP 12), the process ends.

  When the warm-up is not completed from low power (NO in STEP 10), and when the warm-up has not been switched to low power (NO in STEP 12), the warm-up is started from low power and the warm-up is started. Up is not completed.

  Since the temperature control in FIG. 5 is periodically executed, the state of the bookbinding apparatus B, specifically, the temperature of the glue in the glue supply unit 81 is always managed by the image control CPU 102.

  In the standby state with the power on, the bookbinding apparatus B is set to a low power state in order to suppress power consumption and avoid evaporation of components in the glue. In the low power state, the glue is set at a temperature of about 80 ° C., for example, and can be warmed up in a relatively short time.

  In the warmed-up state, the paste is heated to a temperature at which it can be melted and applied, for example, about 150 ° C. In order to raise the paste temperature from room temperature to the warmed-up state or from the low power state to the warmed-up state, it takes about 1 to several minutes.

  For this reason, when a job including bookbinding processing is executed, the image forming apparatus A immediately forms an image based on the job execution command signal, but the bookbinding apparatus B is not warmed up and requires a warm-up time. In addition, the entire image forming system requires a waiting time.

  Therefore, in an image forming apparatus that continuously processes a reserved job, if a job that includes a bookbinding process is included in the reserved job, the system operation stops before the bookbinding job. descend.

  In the present invention, the time of the operation command signal sent from the image forming apparatus A to the bookbinding apparatus B is determined based on the preparation time when the post-processing apparatus becomes operable after receiving the job execution command signal, and the operation command signal is As a result, the bookbinding apparatus B is in an operable state in advance before the end of the job in the image forming apparatus A, that is, during execution of the job.

  The control for the bookbinding apparatus B will be described with reference to the flowchart of FIG. The control in FIG. 6 is performed by the image control CPU 102 as job control means.

  If it is determined in STEP 21 that a job (job in the image forming apparatus) is being executed (YES in STEP 21), whether or not there is a job (second job) including bookbinding processing among a plurality of registered reserved jobs. Is determined (STEP 22). A job including bookbinding processing is a job for forming an image on a recording sheet and binding a plurality of image-formed recording sheets to form a book, and hereinafter referred to as a bookbinding job.

  If there is no bookbinding job (NO in STEP 22), the job processing is continued and terminated (STEP 28).

  When there is a bookbinding job in the reserved job, it is determined whether or not the post-processing apparatus is in a low power state (STEP 23).

  As described above, the post-processing apparatus is set to a warm-up state in which the glue (hot melt adhesive) used for bookbinding is kept in a usable molten state and a low power state that is a low power consumption state. The In the low power state, the paste is not heated to the melting temperature, but is maintained at a temperature that allows the transition to the molten state within a relatively short time. For example, in the warmed-up state, the paste is held at 150 ° C., and kept at 80 ° C. in the low power state.

  If the post-processing device is not low power (NO in STEP 23), the post-processing device preparation work, that is, warm-up is not required, so the job processing is continued and terminated (STEP 28).

  When the post-processing device is low power (STEP 23: yes), the time Tr until the previous job (first job) of the bookbinding job is completed is calculated (STEP 24), and further, the post-processing device is warmed up. The required time Tw is calculated (STEP 25). The time required for warm-up is the time for heating the glue in the bookbinding apparatus to the melting temperature, and is determined based on the temperature of the glue detected by the temperature sensor 203 (actually, the temperature near the glue supply means 81). Is done.

  In STEP 26, Tw ≧ Tr is determined. If no, the succeeding job is executed and the process ends (STEP 28). If yes, the bookbinding apparatus B is requested to start warm-up (STEP 27), and the subsequent job is executed and terminated (STEP 28). Since the control shown in FIG. 6 is repeatedly executed periodically, when the remaining time Tr until the completion of the previous job of the bookbinding job becomes shorter than the warm-up time Tw of the post-processing device according to STEPs 27 and 28, Warm-up of the processing apparatus is started. Therefore, the bookbinding process in the bookbinding job can be performed in a continuous image forming process without interrupting the image forming process.

  If it is determined in STEP 21 that the job is not being executed, it is determined whether there is a registered reserved job (STEP 31). If there is no registered job (NO in STEP 31), but if there is a registered job (YES in STEP 31), it is determined whether there is a bookbinding job in the registered job (STEP 32).

  When there is a bookbinding job (YES in STEP 32), it is determined whether or not the post-processing apparatus is in low power (STEP 33). When not in low power, that is, when the post-processing apparatus is in an operable state, job execution is started (STEP 35), and when in low power, the post-processing apparatus is requested to warm up (STEP 34). .

  The process ends after STEPs 34 and 35.

  If it is determined in STEP 32 that the registered job is not a bookbinding job (NO in STEP 32), it is determined whether or not the post-processing apparatus is in low power (STEP 36).

  When the power is low (YES in STEP 36), the process ends. When the power is not low, the remaining job end time Tr is calculated (STEP 37).

  In the calculation of the time Tr in STEP 37, if the bookbinding job is not included in the remaining jobs, the time until the processing of all jobs is completed is calculated. If the bookbinding job is included, the time of the bookbinding job is calculated. The time to complete the previous job is calculated.

  Next, in STEP 38, the time Tr until the completion of the job is compared with the time Ti required to shift the post-processing apparatus to the low power state.

As described above, there are a warm-up state and a low-power state. In these states, the glue supply means 81 of the bookbinding apparatus is temperature-adjusted to each optimum temperature. The time Ti for shifting to the low power state is the time until the bookbinding apparatus can be switched from temperature adjustment in the warm-up state to temperature adjustment in the low power state.
When Tr ≧ Ti (STEP 38: yes), that is, when the remaining job processing time is equal to or longer than the low power shift time, a request to shift to low power is issued (STEP 39). Since the processing of STEP 39 avoids unnecessarily maintaining the binding glue at a high temperature, evaporation of hot melt adhesive components and waste of electric power can be avoided.
When Tr ≧ Ti is not satisfied (NO in STEP 38), the job is executed and the process is terminated.

(1) Comparative Example 1
In this example, the next job 1 and job 2 are continuously executed.
・ Job 1: A4 size, 2 sheets of 100 sheets on one side, no post-processing ・ Job 2: A4 size, 1 sheet of 100 sheets on one side, bookbinding process ・ Glue temperature in low power state: 80 ° C.
・ Glue temperature 150 ℃ in warm-up condition
Image formation requires 0.6 seconds per sheet. Bookbinding processing requires 20 seconds. Time required to raise the paste temperature by 1 DEG C .: 1 second Job 1 under the above apparatus conditions , 2 is as shown in FIG. 7A.

Time required for job 1 = 0.6 × 200 = 120 seconds = 2 minutes Time required for job 2 = time required for image formation 0.6 × 100 + book warm-up time 1 × (150-80) + bookbinding time 20
The total time required was 270 seconds, 4 minutes and 30 seconds.
(2) Example 1
Job 1 (A4 size, 100 copies on one side, no post-processing) and job 2 (A4 size, 100 copies on one side, bookbinding) similar to Comparative Example 1 were executed under the same apparatus conditions as in Comparative Example 1. .

  The required time is shown in FIG.

Time required for job 1 = 0.6 × 200 = 120 seconds = 2 minutes Time required for job 2 = time required for image formation 0.6 × 100 + time required for bookbinding 20
The total time required was 200 seconds, 3 minutes and 20 seconds.
(3) Comparative Example 2
・ Job 1: A4 size, 100 copies on one side, bookbinding processing ・ Job 2: A4 size, 6 copies on 100 pages, no post-processing ・ Job 4: A4 size, 6 copies on 100 pages, no post-processing ・ Job 4 : A4 size, 100 copies on one side, bookbinding processing The apparatus conditions are the same as those in Comparative Example 1 and Example 2.

  In bookbinding in job 1, since the bookbinding apparatus is in a warm-up state, there is no warm-up time and bookbinding processing can be performed immediately.

  Further, after the completion of job 1, the bookbinding apparatus shifts from the warm-up completed state to the low power state, but the transition time is 10 minutes. However, since processing of jobs 2 and 3 takes 720 seconds = 12 minutes, the bookbinding apparatus is shifted to the low power state when job 3 ends and job 4 starts.

Job 1 commercial time = 0,6 × 200 + 20 = 140 seconds Job 2 required time = 0.6 × 600 = 360 seconds Job 3 required time = 0.6 × 600 = 360 seconds Job 4 required time = 0. 6 × 100 + 20 = 80 seconds The time required only to execute jobs 1 to 4 is as described above, but at the end of job 3, since the bookbinding apparatus is in the low power state, the warm-up state is changed from the low power state. Warm-up time for transitioning to is interposed between job 3 and job 4. For this reason, the operation of the system is interrupted between job 3 and job 4.

Further, it is assumed that the bookbinding apparatus has a power saving design that automatically shifts from the warm-up completed state to the low power state when 10 minutes have elapsed after the bookbinding process is completed. Since the required time for jobs 2 and 3 is 12 minutes, the state is shifted from the warmed state to the low power state 2 minutes before the end of job 3.
(4) Example 2
Similar to the comparative example, the following four jobs were executed.
・ Job 1: A4 size, 100 copies on one side, bookbinding processing ・ Job 2: A4 size, 6 copies on 100 pages, no post-processing ・ Job 4: A4 size, 6 copies on 100 pages, no post-processing ・ Job 4 : A4 size, 100 copies per side, bookbinding process The required time for four jobs is as follows.

Job 1 commercial time = 0,6 × 200 + 20 = 140 seconds Job 2 required time = 0.6 × 600 = 360 seconds Job 3 required time = 0.6 × 600 = 360 seconds Job 4 required time = 0. 6 × 100 + 20 = 80 seconds As is clear from FIG. 6, during execution of jobs 2 and 3, the remaining required time Tr of these jobs is compared with the warm-up time Tw, and when Tw ≧ Tr, the warm-up is performed. Therefore, in the case of the second embodiment, there is no interruption between the job 3 and the job 4, and continuous processing from the job 3 to the job 4 is performed.

  At the end of job 1, the required time Tr of jobs 2 and 3 without bookbinding processing is compared with the time Ti required for the state transition from the warm-up state to the low power state. When the time is longer, switching to low power is executed immediately at the end of job 1. This suppresses evaporation of the hot melt adhesive and achieves power saving.

1 is a schematic diagram of an image forming system according to an embodiment of the present invention. It is a perspective view of a bookbinding apparatus. It is a block diagram of a data processing and a control system. It is a figure which shows the setting screen of an operation part. It is a flowchart of the temperature control in a bookbinding apparatus. It is a flowchart of the state control in embodiment of this invention. It is a figure which shows the job required time in an Example and a comparative example.

Explanation of symbols

102 Image control CPU
201 Post-processing device control unit 202 Heater 203 Temperature sensor

Claims (9)

Image forming apparatus for forming an image on a sheet, an image forming system having a job control means for controlling the accessory device and the image forming equipment is connected to the image forming apparatus, a plurality of jobs are registerable, continuously registered job in executable images forming system,
It said job control means, wherein after the first job prior not required before the output time quasi備時between the job attachment device, first requires a preparation time of the accessory device in front of the output time of the job when executing the second job, in parallel to prepare for the accessory device for the second job during the output of the preceding first job run, the prior SL until the output of the first job is completed as preparation of the accessory device for second job is completed, and exits the preparation start command of the accessory device for the second job during the output time of the first job, and ends the output of the first job An image forming system starting output of the second job later .   The image forming system according to claim 1, wherein the attachment device includes a heater, and the preparation time is a warm-up time by the heater.   3. The image forming system according to claim 2, wherein the attachment device includes a bookbinding device including a gluing unit that uses a glue that is heated and melted by the heater and binds the sheets. 4.   The image forming system according to claim 3, further comprising: a temperature sensor that detects a temperature of the glue, wherein the job control unit performs temperature management of the glue based on a temperature detected by the temperature sensor. .   The bookbinding apparatus can be set to a warmed-up state in which the glue is applied and maintained at a melting temperature, and a low power state in which the glue is maintained at a temperature lower than the melting temperature. -Comparing the warm-up time required for shifting from the power state to the warm-up completed state with the remaining time until the first job is completed, and determining the timing of issuing the preparation start command based on the comparison result The image forming system according to claim 3, wherein the image forming system is determined. The job control means compares the output time of the first job with the warm-up time, and determines whether or not the warm-up completed state can be canceled based on the comparison result. The image forming system described. In an image forming method for continuously executing a plurality of registered jobs,
After the preceding first job that does not require a previous job output time preparation time for post-processing, executes the second job that requires a preparation time for post-processing before output time of the job If, compared with the preparation time for post-processing of the output time and the second job to the output of the first job is completed, based on the comparison result, wherein during the output time of the first job An image forming method comprising: starting preparation for post-processing of a second job, and starting output of the second job after finishing output of the first job .   The image forming method according to claim 7, wherein the second job is a bookbinding process in which sheets are bound by gluing, and the preparation time is a warm-up time for heating the glue to a melting temperature. When the post-processing apparatus is in the warm-up completed state, the output time of the first job is compared with the preparation time, and it is determined whether the warm-up completed state can be canceled based on the comparison result. The image forming method according to claim 7 or 8.