JP7491141B2 - Image forming apparatus and program - Google Patents

Description

The present invention relates to an image forming device and a program.

A post-processing device that performs a specific post-processing is connected to an image forming device such as a multifunction peripheral/printer (MFP) or an inkjet printer. The post-processing performed by the post-processing device includes inserting other printed sheets as a cover or slip sheet, folding the sheets, punching holes in the sheets, aligning and stacking the sheets, and stapling multiple sheets of paper together.

Each post-processing is performed by an independent post-processing unit. The user can specify the type of post-processing to be performed within a job on an image formation job (print job) basis. When the type of post-processing is changed, preparation time is required before and after the change. There is technology to shorten this preparation time (see, for example, Japanese Patent Laid-Open No. 2003-233666). In the image forming device of Japanese Patent Laid-Open No. 2003-233666, the next print job is started without waiting for the post-processing device to complete preparations to change the post-processing, and the post-processing device starts post-processing of the print job immediately after completing preparations to change the post-processing.

In the technology disclosed in Patent Document 1, paper is supplied at the timing when post-processing recovery preparation operations are completed. However, in an image forming device, a print job may be interrupted. In the technology disclosed in Patent Document 1, it is not possible to control the timing of paper supply when a print job is resumed from a state in which it was interrupted due to such circumstances.

The present invention was made in consideration of the above circumstances, and aims to provide a technology that reduces downtime when a print job is interrupted.

In order to solve the above technical problems, one aspect of the present invention is an image forming device that executes a print job that forms an image on a sheet-like medium, comprising an image forming section that forms an image on the medium, a paper feed section that supplies the medium to the image forming section, a post-processing section that has a post-processing unit that performs post-processing on the medium supplied from the image forming section, a transport control section that supplies the medium to a predetermined supply position when the recovery preparation time of the cause unit, which is the post-processing unit where the operation was performed, has elapsed after the print job is interrupted due to an operation in the post-processing unit, and a print control section that performs image creation preparation so that the transport control section can control the medium to the supply position, and the print control section starts the image creation preparation at the print job restart time calculated based on the length of the transport path of the paper feed section connected to the image forming section, and the supply position is the entrance of the post-processing section.

The present invention can reduce downtime when an image forming job is interrupted.

1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment. 1 is a hardware configuration diagram of an image forming apparatus according to a first embodiment. FIG. 1A is a functional block diagram of a controller according to a first embodiment, and FIGS. 1B to 1D are explanatory diagrams for explaining a configuration information table, a transport time table, and a return time table according to the first embodiment, respectively. 3A and 3B are explanatory diagrams for explaining a stacker according to a first embodiment; FIG. 1A is a diagram illustrating a print job start time according to a first embodiment, and FIG. 1B is a diagram illustrating a conventional print job start time. 10 is a flowchart of a print job restart time setting process according to the first embodiment. 13A is a flowchart of a print job restart time setting process according to a modified example of the first embodiment, and FIG. 13B is an explanatory diagram for explaining a print job start time according to the modified example. 13A and 13B are diagrams illustrating the state of a tray in a stacker in another modified example of the first embodiment, and FIG. 13C is a flowchart of a print job resume time setting process in the same modified example. FIG. 11 is a functional block diagram of a controller according to a second embodiment. 13 is a flowchart of an abnormality detection process according to a second embodiment. 13 is an explanatory diagram for explaining a configuration of an image forming unit according to a modified example of the second embodiment. FIG. 13A and 13B are flowcharts of a paper transport control process in a print job stop process according to a modified example of the second embodiment. 13 is a flowchart of an abnormality detection process according to a modified example of the second embodiment.

Below, an embodiment of an image forming apparatus equipped with a post-processing device and a program according to the present invention will be described with reference to the drawings. In each drawing for describing the embodiment, components such as parts and components having the same function or shape are given the same reference numerals as far as they can be distinguished, and repeated description will be omitted.

<<First embodiment>>
A first embodiment of the present invention will be described. As described above, a wide variety of post-processing operations are performed in the post-processing device connected to the image forming apparatus. When the post-processing unit is operated (such as removing a jam, replacing staples, or removing a stacker tray), the print job that has been executed up until that point is temporarily interrupted. After the reason for interruption is eliminated, that is, after the post-processing unit is ready to return to its original state, the interrupted print job is resumed. Conventionally, image formation was started after the post-processing unit was ready to return to its original state, but in this embodiment, the timing of resuming image formation is controlled so that image formation is completed at the timing when the post-processing unit is ready to return to its original state.

The device and control process of this embodiment that realizes the above process will be described. In the rest of this specification, the term "image forming device" will include post-processing devices and paper feeders.

Figure 1 is a schematic diagram of an example of an image forming device 100 according to this embodiment. In this embodiment, the image forming device 100 is described as an example of a multifunction peripheral (MFP: Multi Function Peripheral/Printer) having at least two of the following functions: copy function, printer function, scanner function, and facsimile function; however, the present invention can be applied to any image forming device 100, such as a copier, printer, scanner device, or facsimile device.

The image forming apparatus 100 of this embodiment includes a large-capacity paper feed unit 400, an image forming unit 300, a post-processing unit (post-processing device) 200, and a controller 910 (see FIGS. 2 and 3). The components constituting the image forming apparatus 100 are connected, for example, by a communication cable.

[Large capacity paper feeder]
The large-capacity paper feed section 400 supplies a sheet-shaped recording medium to the image forming section 300. The recording medium used in the large-capacity paper feed section 400 according to this embodiment and other configurations including the image forming section 300 may be a sheet-shaped recording medium that can be transported, stacked, bound, or the like. In the following, in this embodiment, "paper" is used as an example of a recording medium, but is not limited to paper. In this figure, a case in which two large-capacity paper feed units 410 and 420 are provided is illustrated. Note that a connection unit 411 is disposed between the large-capacity paper feed units 410 and 420. The connection unit 411 connects the large-capacity paper feed unit 410 and the other large-capacity paper feed unit 420. Note that the number of large-capacity paper feed units is not important.

[Image forming unit]
The image forming section 300 forms an image on a sheet of paper supplied from the large-capacity paper supply section 400. The sheet of paper on which the image has been formed by the image forming section 300 is output to the post-processing device 200.

The image forming unit 300 forms an image, for example, by electrophotography. In the electrophotography image forming unit 300, first, an electrostatic latent image is formed according to the image data by irradiating optical image data such as a laser beam onto a photosensitive drum that has been uniformly charged by a charger. After the electrostatic latent image is formed, toner supplied from a toner cartridge is attached to the electrostatic latent image. After the toner is transferred from the photosensitive drum to which the toner has been attached, the toner is fixed to the paper by a fixing unit, thereby forming an image on the paper according to the image data. Note that the image forming unit 300 can employ various image forming methods, such as an inkjet method, in addition to the electrophotographic method.

The image forming unit 300 of this embodiment includes, for example, a paper feed tray (bank feed unit), a purge unit, a photoconductor, and an intermediate transfer belt. These are the same as the general mechanisms of a general electrophotographic process, so detailed explanations are omitted.

As shown in FIG. 1, paper on which an image has been formed in the image forming section 300 is transported in the direction of arrow A along the transport path indicated by the dotted line. That is, paper on which an image has been formed in the image forming section 300 and discharged is transported to the post-processing device 200, passes through each post-processing unit of the post-processing device 200, and is discharged.

[Post-processing device]
The post-processing device 200 performs various post-processing processes on the paper on which an image has been formed in the image forming section 300. Each post-processing process is realized by a post-processing unit that performs the respective post-processing process. FIG. 1 illustrates an example in which the post-processing units include a paper cooling unit 240, an inserter 250, a folding unit 260, a ring binding unit 270, a stacker 280, and a finisher 290. Note that it is not necessary to include all of the post-processing units. In the following, when there is no need to distinguish between the post-processing units, they will be represented by post-processing unit 201.

The paper cooling unit 240 cools the printed paper. The inserter 250 inserts already printed paper as a cover or slip sheet. The folding unit 260 folds the paper. The ring binding unit 270 punches the paper and performs ring binding on bundles of multiple sheets. The stacker 280 aligns the printed paper and stacks it in large quantities. The finisher 290 punches the paper and staples it into bundles of multiple sheets.

Each post-processing unit 201 has one or more sensors that detect the state of its own device. Signals detected by the sensors are sent to the controller 910. The attached sensors include, for example, an abnormality detection sensor that outputs an abnormality detection signal when an abnormality such as a jam is detected, and a door sensor that outputs an open signal or a close signal depending on whether the door is open or closed. The sensor signal output from each sensor includes information identifying the post-processing unit 201 to which the sensor is attached and information identifying the sensor.

[controller]
The controller 910 controls the overall operation of the image forming apparatus 100. For example, the controller 910 generates an image formation instruction based on a print instruction based on image data obtained by an image reading unit that optically scans an original on which an image is formed, a print instruction input from an operation unit, or a print instruction of image data received from a general-purpose PC (Personal Computer) or the like. The image formation instruction includes at least image formation information (sometimes called a print job) that is information for the image forming unit 300 to execute image formation, and setting values for the post-processing device 200 to execute post-processing.

In addition, in this embodiment, the restart time of the print job is also set if the print job is interrupted due to operation of the post-processing device 200.

[Hardware configuration]
Here, a hardware configuration of the image forming apparatus 100 of this embodiment will be described. Fig. 2 is a hardware configuration diagram of the image forming apparatus 100 of this embodiment. As shown in this figure, the image forming apparatus 100 of this embodiment includes a controller 910, a short-range communication circuit 920, an engine control unit 930, an operation panel 940, and a network I/F 950.

Of these, the controller 910 has a CPU 901, which is the main part of the computer, a system memory (MEM-P) 902, a north bridge (NB) 903, a south bridge (SB) 904, an ASIC (Application Specific Integrated Circuit) 906, a local memory (MEM-C) 907, which is a storage unit, an HDD controller 908, and a HD 909, which is also a storage unit, and is configured such that the NB 903 and the ASIC 906 are connected by an AGP (Accelerated Graphics Port) bus 921.

Of these, the CPU 901 is a control unit that performs overall control of the image forming apparatus 100. The NB 903 is a bridge that connects the CPU 901 with the MEM-P 902, the SB 904, and the AGP bus 921, and includes a memory controller that controls reading and writing to the MEM-P 902, a PCI (Peripheral Component Interconnect) master, and an AGP target.

The MEM-P 902 includes a ROM 902a, which is a memory for storing programs and data that realize the various functions of the controller 910, and a RAM 902b, which is used for expanding the programs and data, and as a drawing memory during memory printing. The programs stored in the RAM 902b may be provided by recording them in an installable or executable format on a computer-readable recording medium such as a CD-ROM, CD-R, or DVD.

SB904 is a bridge for connecting NB903 to PCI devices and peripheral devices. ASIC906 is an integrated circuit (IC) for image processing applications that has hardware elements for image processing, and serves as a bridge connecting AGP bus921, PCI bus922, HDD controller908, and MEM-C907. This ASIC906 includes a PCI target and AGP master, an arbiter (ARB) that is the core of ASIC906, a memory controller that controls MEM-C907, multiple DMACs (Direct Memory Access Controllers) that rotate image data using hardware logic, and a PCI unit that transfers data between scanner unit931 and printer unit932 via PCI bus922. In addition, a USB (Universal Serial Bus) interface or an IEEE1394 (Institute of Electrical and Electronics Engineers 1394) interface may be connected to the ASIC 906.

MEM-C907 is a local memory used as an image buffer for copying and a code buffer. HD909 is a storage for storing image data, font data used during printing, and forms. HD909 controls the reading and writing of data from and to HD909 under the control of CPU901. AGP bus921 is a bus interface for a graphics accelerator card proposed to speed up graphic processing, and by directly accessing MEM-P902 with high throughput, the graphics accelerator card can be made faster.

The short-range communication circuit 920 also includes a short-range communication I/F 920a. The short-range communication circuit 920 is a communication circuit such as NFC or Bluetooth (registered trademark).

The engine control unit 930 further includes a scanner unit 931 and a printer unit 932. The operation panel 940 further includes a panel display unit 940a, such as a touch panel, that displays the current settings and selection screens and receives input from the user, and an operation panel unit 940b that includes a numeric keypad that receives settings for image formation conditions such as density settings, and a start key that receives a copy start command.

The image forming device 100 can sequentially switch between the document box function, copy function, printer function, and facsimile function using the application switching key on the operation panel 940. When the document box function is selected, the document box mode is selected; when the copy function is selected, the copy mode is selected; when the printer function is selected, the printer mode is selected; and when the facsimile mode is selected, the facsimile mode is selected.

The network I/F 950 is an interface for data communication using a communication network. The short-range communication circuit 920 and the network I/F 950 are electrically connected to the ASIC 906 via the PCI bus 922.

The controller 910 controls the entire image forming device 100, for example, drawing, communication, and input from the operation panel 940. The scanner unit 931 or the printer unit 932 includes an image processing section such as error diffusion and gamma conversion.

In addition, in this embodiment, the controller 910 further receives various signals from the post-processing device 200 and outputs control signals to the post-processing device 200, thereby controlling the operation of the post-processing device 200.

[Function block]
FIG. 3 is a functional block diagram of the controller 910 of this embodiment, showing functions related to the processing of this embodiment.

The controller 910 of this embodiment includes a print control unit (print control means) 961, a transport control unit (transport control means) 962, a monitoring unit 963, a required time calculation unit 964, and a restart time setting unit 965. Each of these units is registered in the ROM 902a as a program. Then, the CPU 901 deploys the program in the RAM 902b and executes it to achieve the above.

Data required to realize each of these units is registered in the ROM 902a. In this embodiment, for example, a configuration information table 971, a transport time table 972, and a return time table 973 are registered. Note that information equivalent to the information contained in the configuration information table 971 may be obtained from each of the post-processing devices 200 communicably connected to the image forming device 100 when the image forming device 100 is started, and stored in the RAM 902b. That is, information related to the configuration of the image forming device 100 used in the control process described below may be set in the controller 910 in advance, or may be obtained from each device connected when the image forming device 100 is operating.

When the print control unit 961 receives a print instruction from the user, it operates each unit of the image forming unit 300 to execute an image formation job (print job). If the print job is interrupted, it resumes the print job from the restart time set by the restart time setting unit 965. In this embodiment, the interruption of the print job is caused by an operation of the post-processing device 200. Here, the operation of the post-processing device 200 refers to an operation that cannot be performed without interrupting the print job, such as an operation to recover from a "jam" in which paper is stuck in the transport path, an operation to refill or replace binding materials (such as staples) used in the binding process, and an operation to remove and attach trays, including replacing the stacking tray.

The transport control unit 962 controls the transport of paper within the image forming device 100. In this embodiment, it monitors the position and transport speed of the paper and controls the transport of the paper. In addition, when a print job is interrupted, the paper is transported (supplied) to a predetermined paper supply position at the resume time calculated by the required time calculation unit 964.

The monitoring unit 963 receives signals from sensors provided in each part constituting the image forming apparatus 100, and monitors the configuration of the image forming apparatus 100, the state of each part, the operating status of each part, etc. In this embodiment, for example, the monitoring unit 963 updates the configuration information stored in the configuration information table 971 in response to signals from each sensor. For example, when a non-acceptance signal indicating that the post-processing unit 201 is not acceptable is received from the sensor of a specific post-processing unit 201, the data of the post-processing unit 201 in the configuration information table 971 is updated to a non-acceptance state. Details of the processing by the monitoring unit 963 will be described in the explanation of each part below.

When a print job is interrupted, the required time calculation unit 964 calculates the time required to resume the print job as the recovery preparation time and the print transport time. In this embodiment, the required time is calculated based on the configuration of the connected device and the sensor signals from the various sensors equipped in the post-processing unit 201. Details of the calculation will be described later.

The restart time setting unit 965 calculates and sets the restart time for the print job using the recovery preparation time and print transport time calculated by the required time calculation unit 964. The print control unit 961 and transport control unit 962 perform control based on the restart time set by the restart time setting unit 965. Details of the settings will be described later.

In the configuration information table 971, information on each part constituting the image forming device 100 is registered. For example, as shown in FIG. 3B, information (ID) identifying the large-capacity paper feed unit 400 and each post-processing unit 201 connected to the image forming unit 300, the connection order, connection status, and status of each device including the image forming unit 300 are registered.

In this embodiment, when the system starts up, the controller 910 detects what devices are connected and in what order, and stores this information in a configuration information table 971. Thereafter, as described above, the monitoring unit 963 updates the status information, operation information, etc. of the sending device each time it receives a signal from the sensor of each unit.

In addition, various information is registered for each device according to the sensors attached to each device. For example, in the case of stacker 280, the door open/close status, tray position, etc. are also registered, as described below.

As shown in FIG. 3(c), the transport time table 972 registers the transport time required for paper to pass through each section in each device constituting the image forming apparatus 100. This information is set in advance. In this embodiment, for example, the time (300a) for transporting paper from each large capacity paper feed unit 410, 420 to the position where writing can start in the image forming section 300, the time (300b) for transporting paper from the position where writing can start to the exit of the image forming section 300, and the time required for paper to pass through each post-processing unit 201 are stored.

As shown in FIG. 3(d), the recovery time table 973 registers the time required for each section to recover when printing is interrupted. In this embodiment, for example, this includes the image formation preparation time in the image forming section 300, the lifting time for the paper feed tray in the stacker 280 to rise from the lower limit position to the upper limit position, the time from closing the door in each section until it is ready to accept paper, etc.

[Required time calculation process]
Here, the calculation process of the time required to resume a print job by the required time calculation unit 964 will be described. Here, the cause of the interruption is assumed to be removal of paper due to the stacker 280 becoming full. When a print job is interrupted, the following time is required before the print job can be resumed: preparation time within the post-processing unit 200 (return preparation time Ts), print preparation time in the image forming unit 300, and paper transport time between the large-capacity paper feed unit 400 and the image forming unit 300. Hereinafter, the print preparation time and paper transport time will be collectively referred to as print transport time Tp.

First, we will explain the operation of each part of stacker 280 when stacker 280 becomes full. When stacker 280 becomes full in image forming device 100, the print job is temporarily suspended, the paper is removed from stacker 280, and then the job is resumed.

As shown in FIG. 4(a), the stacker 280 includes a tray 281 that can be raised and lowered, a cart 282 that carries the tray 281, a door 283, a switch 284 that raises and lowers the tray 281, a tray position sensor 286, a cart sensor 287, a door sensor 288, and a jam detection sensor 289.

When there is no paper loaded, the tray 281 waits at the upper limit position (highest position). Supplied paper is always stacked on top of the tray 281. In other words, when the tray 281 receives paper while positioned in the waiting position, it gradually descends as more paper is loaded. Then, when the tray 281 descends to the lower limit position (lowest position), it is considered full and the stacker 280 stops accepting paper. This also interrupts the print job.

The tray 281 is combined with a dolly 282 having casters to form a cart 285 as shown in FIG. 4(b). When removing the paper loaded on the tray 281, the user opens the door 283 of the stacker 280, places the paper loaded on the tray 281 directly on the dolly 282, and carries it away.

Once the paper loaded in tray 281 has been removed, the user returns the dolly 282 and tray 281 (cart) to the stacker 280 and closes the door 283 in order to perform the next print job.

It is also possible to remove paper stacked in tray 281 when it is not full. In this case, the user presses switch 284 to lower tray 281 to the lowest position. The paper is then removed in the same manner as above. It is also possible to remove paper stacked in tray 281 when tray 281 is not full by leaving tray 281 in its current position without lowering it.

Each of the above operations is performed by the sensors detecting the state of each part of the stacker 280 and sending the sensor signal to the monitoring unit 963, and is performed by instructions from the controller 910. The monitoring unit 963 receives the sensor signal, stores it in the configuration information table 971, and performs various judgments.

The tray position sensor 286 detects the position of the tray 281 and outputs a sensor signal to the monitoring unit 963. Each time the monitoring unit 963 receives a signal from the tray position sensor 286, it stores the latest value in the configuration information table 971. This makes it possible to obtain position information when the tray 281 stops operating by referring to the configuration information table 971.

In addition, in this embodiment, for example, when the monitoring unit 963 detects that the tray 281 has reached the lower limit position due to a sensor signal from the tray position sensor 286, it outputs a print stop signal to the print control unit 961 to instruct it to stop printing, and outputs a transport stop signal to the transport control unit 962 to stop transporting paper. Furthermore, at this time, the monitoring unit 963 determines that the state of the stacker 280 is unacceptable until it receives a signal from the tray position sensor 286 indicating that the tray 281 has reached the upper limit position, and registers this in the configuration information table 971.

The trolley sensor 287 detects when the trolley 282 is placed in a predetermined position and outputs a sensor signal.

When the door 283 of the stacker 280 is closed, the door sensor 288 outputs a sensor signal (door closed signal) that indicates that the door 283 is closed. When the monitoring unit 963 receives the door closed signal, it raises the tray 281 to the upper limit position at which the tray 281 can accept paper. For example, it outputs a lift command to the motor that drives the tray 281.

The jam detection sensor 289 is a type of abnormality detection sensor, and outputs a jam detection signal when it detects the occurrence of a jam. For example, when the tray 281 is raised to its upper limit position and there is paper left behind, it also outputs a jam detection signal. When the monitoring unit 963 receives a jam detection signal, it makes the sending post-processing unit 201 unacceptable in the configuration information table 971, and stops the print job and paper transport.

When the monitoring unit 963 receives a signal from the switch 284 indicating that the switch has been pressed by the user, the monitoring unit 963 outputs an instruction to lower the tray 281 to the lowest position. For example, the monitoring unit 963 outputs a lowering instruction to the motor that drives the tray 281, and stops the print job and paper transport. At this time, the monitoring unit 963 does not have to lower the tray 281 to the lowest position.

The stacker 280 may be equipped with a controller that determines the position of the tray 281 and whether the door 283 is open or closed, and controls the stacker 280.

In this way, when paper is removed from the stacker 280, the print job is interrupted. At this time, as described above, time is required for the tray 281 to rise to the upper limit position after it is detected that the door 283 is closed. This is the time required for preparation within the post-processing device 200 (return preparation time Ts).

Next, we will explain the printing transport time Tp.

Of the printing transport time Tp, the printing preparation time in the image forming unit 300 is the image creation preparation time Ta in the image forming unit 300.

Of the print transport time Tp, the paper transport time is the time it takes to transport the paper from the paper feed tray to a predetermined supply position. In this embodiment, the predetermined supply position is the entrance of the post-processing device 200. First, the paper transport path in the image forming device 100 of this embodiment will be described with reference to FIG. 1.

In this diagram, P1 is the start position of paper transport when paper is fed from paper feed tray 331. The paper feed source may be another paper feed tray, but here it is assumed to be paper feed tray 331. P2 is the paper arrival position (image formation start position) where exposure to the photoconductor, i.e., image formation, can begin after paper transport has started. P3 is the paper transport exit of image forming unit 300. In FIG. 1, P4 is the entrance of stacker 280.

In the image forming unit 300, paper is fed from the paper feed tray 331, exposure is started when the paper reaches P2, and the toner image is transferred to the paper, thereby forming an image on the paper. The paper is then discharged from P3 to the post-processing device 200. The paper is then transported from P3 to P4 within the post-processing device 200.

In this way, the image forming unit 300 requires a first transport time Tf for transporting the paper from the exit (paper feed tray exit) P1 of the paper feed tray 331 to the position P2 where writing can start, and a second transport time Tw for transporting the paper from the start of writing to the exit P3 of the image forming unit 300.

Therefore, the paper transport time of the printing transport time Tp is the sum of the first transport time Tf and the second transport time Tw. Then, adding the image creation preparation time Ta to this, Tf + Tw + Ta, is the printing transport time Tp.

The required time calculation unit 964 of this embodiment obtains the return preparation time Ts and the image creation preparation time Ta from the return time table 973, and obtains the first transport time Tf and the second transport time Tw from the transport time table 972. Then, using these, it calculates the return preparation time Ts and the print transport time Tp.

When using other paper feed trays, or when using the paper feed tray of the large-capacity paper feed unit 400, the first transport time Tf is calculated by obtaining the distance from each paper feed tray to the writing start position P2 from the transport time table 972.

[Resume time setting process]
Next, a description will be given of the restart time setting process performed by the restart time setting unit 965. In this embodiment, the restart time setting unit 965 calculates and sets the restart time at which the print job is restarted using the time at which the door close signal is received from the door sensor 288, the return preparation time Ts calculated by the required time calculation unit 964, and the print transport time Tp. The restart time is the time at which image creation preparation starts.

Specifically, as shown in FIG. 5(a), in this embodiment, the resume time is calculated so that the paper is supplied to a predetermined supply position (the entrance of the post-processing device 200) when the return preparation time Ts has elapsed. Specifically, the print job resume time is calculated so that the end time of the return preparation time Ts is the same as the time when the paper is transported to the entrance of the post-processing device 200, which is determined by the print transport time Tp. If the door closing time is T0, the print job resume time is calculated as T0 + (Ts - Tp).

Figure 5(b) shows an explanation of the print job resumption time in a conventional image forming device 100 when a print job is interrupted for a similar reason. In this way, conventionally, the print job is resumed only after the preparation operation time (Ts) in the post-processing device 200 is completely completed, that is, after the post-processing device 200 reaches a state where it can operate normally. Therefore, the time required for the paper to be discharged from the stacker 280 in the resumed print job is Ts+Ta+Tf+Tw+Te, as shown in Figure 5(b).

In contrast, in this embodiment, the interrupted print job is resumed without waiting for the completion of the preparation operation of the post-processing device 200. That is, as shown in FIG. 5A, the timing of the resumption of the print job is controlled so that the paper arrives at the exit P3 of the image forming unit 300 just when the recovery preparation time Ts has elapsed. That is, in this embodiment, printing is started taking into consideration the timing of the arrival of the paper transported to the post-processing device 200 by the resumed print job, so as to coincide with the "time" (timing) when the cause of the interruption is removed and the post-processing device 200 becomes operable again. As a result, according to this embodiment, the time it takes to eject the paper can be shortened.

[Print Job Restart Time Setting Process]
The flow of the print job restart time setting process of this embodiment performed by the required time calculation unit 964 and the restart time setting unit 965 will be described below. Fig. 6 shows a process flow of the print job restart time setting process of this embodiment. This process is started when the print job is interrupted due to the operation of the post-processing unit 201. For example, the process is started when the monitoring unit 963 receives a signal from the tray position sensor 286 of the stacker 280 indicating that the position of the tray 281 has reached the lower limit position, or when the monitoring unit 963 receives a close signal from the door sensor 288 indicating that the door 283 has been closed.

The required time calculation unit 964 calculates the printing transport time Tp (step S1110).

In the printing transport time Tp calculation process of step S1110, first, the required time calculation unit 964 obtains the first transport time Tf from the transport time table 972 (step S1111).

In addition, the first transport time Tf may be calculated according to the following formula (1) using the paper transport speed V1 (mm/s) and the transport path length L1 (mm) from the paper feed tray exit P1 to the writing start position P2.
Tf=L1×1000/V1 (1)
In this case, the paper transport speed V1 (mm/s) and the transport path length L1 (mm) are stored in advance as specifications of each part of the image forming apparatus 100, for example, in the configuration information table 971.

The required time calculation unit 964 also obtains the second transport time Tw from the transport time table 972 (step S1112). The second transport time Tw may also be calculated from the paper transport speed and the transport path length from the writing start position P2 to the exit P3 of the image forming unit 300.

The required time calculation unit 964 also obtains the image creation preparation time Ta from the return time table 973 (step S1113). Note that the order in which the first transport time Tf, the second transport time Tw, and the image creation preparation time Ta are obtained does not matter.

After acquiring the first transport time Tf, the second transport time Tw, and the image creation preparation time Ta, the required time calculation unit 964 adds these together to calculate the print transport time Tp (step S1114). In other words, it calculates Tp = Tf + Tw + Ta.

The required time calculation unit 964 calculates the return preparation time Ts (step S1120). Here, the tray lift time of the stacker 280 is obtained from the return time table 973, and this is set as the return preparation time. Note that the order in which the return preparation time Ts and the print transport time Tp are calculated does not matter.

The restart time setting unit 965 calculates and sets the print job restart time from the return preparation time Ts, the print transport time Tp, and the time T0 when the closing signal is received from the door 283 (step S1130). The print control unit 961 and the transport control unit 962 perform control based on the set print job restart time.

As described above, the image forming apparatus 100 of this embodiment includes a transport control unit 962 that transports paper to a predetermined supply position after a print job is interrupted due to an operation in the post-processing unit 201, and a print control unit 961 that performs image creation preparation so that the transport control unit 962 can control the paper to the supply position after the recovery preparation time Ts of the cause unit, which is the post-processing unit 201 where the operation was performed, has elapsed. The print control unit 961 starts image creation preparation at the print job restart time calculated based on the length of the transport path of the paper feed unit connected to the image forming unit 300, and the supply position is the entrance of the post-processing device 200.

In this way, according to this embodiment, when a print job is interrupted due to the operation of the post-processing unit 201, the print job is resumed so that the paper reaches the exit of the image forming unit 300, i.e., the entrance of the post-processing device 200, at the timing when the post-processing unit 201 (causing unit) that caused the interruption of the print job completes preparations for resuming printing (preparation for recovery). In addition, the transport time from the paper feed tray being used is taken into consideration when calculating the time to resume the print job.

Therefore, according to this embodiment, in a configuration in which the image forming device 100 has multiple paper feed trays, regardless of which paper feed tray paper is fed from, the print job is controlled to be resumed at a timing that allows the paper to reach the exit P3 of the image forming section 300. As a result, if a print job is interrupted due to operation of the post-processing unit 201, the time it takes to eject the printed paper to the post-processing device 200 can be shortened. This makes it possible to shorten the downtime of the print job, and therefore the time required for the entire print job can be shortened, improving printing efficiency.

<Modification 1>
In the above embodiment, the resumption time of the print job is set so that the paper reaches the exit of the image forming unit 300, i.e., the post-processing device 200, at the timing when the post-processing unit 201 is ready to return to its original state, but this is not limited to this.

The restart time of the print job may be set so that the paper reaches the outlet of the post-processing unit 201 that is the most downstream of the post-processing units 201 that can accept paper among the post-processing units 201 connected as the post-processing device 200.

For example, the post-processing units 201 are connected in the order of the above embodiment, and the units other than the stacker 280 are capable of accepting. In other words, the most downstream post-processing unit 201 that can accept is the ring binding unit 270. The exit of the ring binding unit 270 and the entrance of the stacker 280 are designated as P4.

The required time calculation unit 964 further calculates a third transport time Te for transporting the paper from the exit P3 of the image forming unit 300 to the entrance P4 of the stacker 280 (see FIG. 1). The third transport time Te differs depending on the type and number of post-processing units 201 connected to the image forming unit 300. Information on the type and number of post-processing units 201 is obtained from the configuration information table 971. In this embodiment, the paper cooling unit 240, the inserter 250, the folding unit 260, and the ring binding unit 270 are obtained as the post-processing units 201 connected between immediately after the image forming unit 300 and the stacker 280.

The required time calculation unit 964 further obtains the transport time for each of the obtained post-processing units 201 from the transport time table 972, and calculates the third transport time Te by summing them. Note that the third transport time Te may also be calculated using the sheet transport speed in the post-processing device 200 and the transport path length of each post-processing unit 201, using formula (1) in the same way as the first transport time Tf.

The flow of the restart time calculation process in this modified example is shown in FIG. 7(a). The restart time calculation process in this modified example is basically the same as in the above embodiment. However, only the process in step S1110 in which the printing transport time Tp is calculated is different.

In step S1110, the required time calculation unit 964 further calculates the third transport time Te (step S1115). The calculation of the third transport time Te may be performed at any time prior to the calculation of the printing transport time Tp in step S1114.

Then, the required time calculation unit 964 calculates the printing transport time Tp (step S1114). In this modified example, the printing transport time Tp is calculated by adding a third transport time Te to the above embodiment. In other words, Tp = Tf + Tw + Ta + Te is calculated.

The subsequent processing is the same as in the above embodiment.

In this case, the print job start time is further back by the third transport time Te, as shown in FIG. 7(b).

According to this modified example, if a print job is interrupted due to the operation of the post-processing unit 201, the print job is resumed when the recovery preparation is completed and the paper reaches the entrance of the post-processing unit 201. At that time, the start time is calculated according to the configuration of the connected post-processing unit 201.

Therefore, according to this modified example, in a configuration in which multiple post-processing units 201 are connected to the image forming device 100, the time it takes to eject printed paper from the image forming device 100 can be reduced, regardless of the connection configuration of the post-processing units 201. This reduces the downtime of the print job and the time related to the entire print job, improving printing efficiency.

In the above description of the modified example, the post-processing unit 201 that causes the print job to be interrupted and the most upstream post-processing unit 201 that cannot accept the print job are the same post-processing unit 201 (specifically, the stacker 280), but the present invention is not limited to this.

For example, the most upstream post-processing unit 201 that cannot accept paper may be a post-processing unit 201 that is upstream of the post-processing unit 201 that is the cause of the paper being rejected. In this case, the third transport time Te is calculated as the time it takes to transport the paper to the entrance of the most upstream post-processing unit 201 that cannot accept paper.

Whether or not any post-processing unit 201 is unacceptable is determined by referring to the configuration information table 971.

<Modification 2>
In the above embodiment, as shown in Fig. 8A, when stacker 280 becomes full, the print job is interrupted in order to remove the paper. However, as shown in Fig. 8B, when stacker 280 is not full, tray 281 may be stopped midway to remove the paper. In this case, for example, the user interrupts the operation of stacker 280 by pressing switch 284 or opening door 283. Hereinafter, in this modified example, it is assumed that the operation is interrupted by pressing switch 284.

When the tray 281 is at the lowest position, the return preparation time Ts is the time it takes for the tray 281 to rise from the lowest position to the highest position, so it is a fixed value and data previously stored as the return time table 973 can be used. However, when the tray 281 is stopped at an intermediate position, the return preparation time Ts' is the time it takes to rise from that position to the upper limit position. Therefore, the required time calculation unit 964 calculates this rise time from the stopped position to the upper limit position as the return preparation time Ts'.

In this embodiment, the configuration information table 971 stores the time required for the tray 281 to rise to the upper limit position (rise time) depending on the height of the tray 281.

When the required time calculation unit 964 is notified by the monitoring unit 963 that the depression signal of the switch 284 has been pressed, it obtains the height of the tray 281 at that time from the configuration information table 971. It also obtains the rise time associated with the obtained height of the tray 281 from the configuration information table 971, and sets this as the return preparation time Ts'. Note that if the rise time corresponding to the height corresponding to the obtained height of the tray 281 is not registered in the configuration information table 971, it calculates the return preparation time Ts' by interpolation or the like from the rise time associated with a nearby height.

In addition, the configuration information table 971 may store rising speed information (speed curve) for each height of the tray 281, and the required time calculation unit 964 may use this to calculate the rising time (return preparation time Ts').

The process flow of the print job restart time setting process of this modified example is shown in FIG. 8(c). As shown in this figure, it is basically the same as the above embodiment. That is, the required time calculation unit 964 first calculates the print transport time Tp (step S1110). The print transport time Tp may be the time it takes to transport the sheet to the entrance of the post-processing device 200 as in the above embodiment, or it may be the time it takes to transport the sheet to the entrance of the unacceptable post-processing unit 201 as in modified example 1.

Then, in this modified example, the required time calculation unit 964 calculates the rise time as the return preparation time Ts' using the method described above (step S1121).

Then, the required time calculation unit 964 calculates and sets the print job restart time using the print transport time Tp and the return preparation time Ts' (step S1130).

The print job may be stopped by pressing a stop button on the operation panel of the image forming unit 300. The print job may be resumed by pressing a print start button on the operation panel.

According to this modified example, the same effect as the above embodiment and modified example can be obtained regardless of the position (height) at which the tray 281 of the stacker 280 stops.

In the above modified example, the case where the tray 281 of the stacker 280 is stopped midway has been described as an example, but even in this modified example, the post-processing unit 201 on which the operation that causes the print job to be interrupted is performed is not limited to the stacker 280. Any post-processing unit 201 may be used as long as the return preparation time can be calculated based on a sensor signal notified from the post-processing unit 201 on which the operation that causes the print job to be interrupted is performed.

<<Second embodiment>>
Next, a second embodiment of the present invention will be described. In this embodiment, the occurrence of an abnormality during the recovery preparation time is also dealt with. For example, when there is paper left behind in the tray 281. In this embodiment, in such a case, a print job stop process is performed to prevent the occurrence of a new abnormality.

As in the first embodiment, the following description of this embodiment uses as an example a case in which a print job is interrupted due to the operation of the stacker 280 in the post-processing unit 201.

The hardware configuration of the image forming device 100 of this embodiment is the same as that of the first embodiment. In addition, the controller 910 of the image forming device 100 of this embodiment is basically the same as that of the first embodiment, but further includes an abnormality detection unit 966 as shown in FIG. 9.

When the abnormality detection unit 966 calculates the recovery preparation time Ts or Ts' (hereinafter referred to as Ts), it monitors the post-processing unit 201 until Ts has elapsed, and if an abnormality is detected, it performs a print job stop process.

In this embodiment, abnormalities are detected by monitoring updates to the configuration information table 971 by the monitoring unit 963. That is, when the monitoring unit 963 receives, for example, a jam detection signal, it changes the status of the device that sent the signal in the configuration information table 971 to information indicating an abnormality. When the status of the configuration information table 971 is changed to information indicating an abnormality, the abnormality detection unit 966 determines that an abnormality has occurred. Note that the abnormality detection unit 966 may be configured to receive the sensor signal directly.

In addition, in the print job stop process, the abnormality detection unit 966 outputs a print stop signal to the print control unit 961 to stop the print job, and outputs a transport stop signal to the transport control unit 962.

When the print control unit 961 receives a print stop signal, it interrupts the print job. Also, when the transport control unit 962 receives a transport stop signal, it stops transporting the paper.

Note that the abnormality is not limited to the detection of a jam. Furthermore, the occurrence of the abnormality is not limited to the stacker 280. It may occur in another device.

[Abnormality detection process]
The following describes the flow of the abnormality detection process by the abnormality detection unit 966. Fig. 10 is a process flow of the abnormality detection process. This process is started when the return preparation time Ts is calculated.

First, the abnormality detection unit 966 sets the recovery preparation time Ts to the monitoring period Tm (step S2101).

After that, at each predetermined time interval, the anomaly detection unit 966 determines whether the monitoring period Tm has elapsed (step S2102). If the period has elapsed, the process ends.

On the other hand, if the time has not elapsed, the abnormality detection unit 966 determines whether or not an abnormality has occurred (step S2103). Here, if the controller 910 receives an abnormality signal from any of the post-processing units 201, it is determined that an abnormality has occurred. If an abnormality signal has not been received, the process returns to step S2102.

If the abnormality detection unit 966 determines that an abnormality has occurred, it performs a print job stop process (step S2104) and terminates the process.

After the print job is interrupted in this manner and the user performs recovery processing, the controller 910 may set the print job resume time using the method described in the first embodiment above.

For example, if the abnormality is a jam in the stacker 280, the user removes the remaining paper from the stacker 280 and closes the front door of the post-processing unit 201. When the controller 910 receives a door close signal from the stacker 280, it performs the print job restart time setting process of the first embodiment.

Furthermore, monitoring is also performed during the recovery preparation operation during the process of setting the print job restart time again. For example, when the user removes the remaining paper from the post-processing unit 201 and closes the door of the post-processing unit 201, the recovery preparation operation of the post-processing unit 201 is performed. By driving the conveying motor etc. during this operation, there is a possibility that remaining paper that has not been detected before will be detected again. In that case, the print job is interrupted again.

As described above, according to this embodiment, if an abnormality is detected before the preparatory operation of the post-processing device 200 is completed, the paper transport can be stopped. As a result, paper is not transported to a post-processing unit 201 that is not capable of accepting paper, and the occurrence of an abnormality, such as a new transport jam, in the post-processing unit 201 can be prevented.

<Modification 3>
In the above embodiment, in the process of stopping the print job when an abnormality occurs, the transport of the paper is stopped at that point, but the present invention is not limited to this.

For example, if the paper is inside the image forming unit 300, the paper may be transported to the exit of the image forming unit 300 before being stopped from being transported.

In addition, if the paper is inside the image forming unit 300, it may be transported to a predetermined position within the image forming unit 300, not limited to the exit, and then stopped. The predetermined position is, for example, a position where the paper is in a reusable state.

The schematic configuration of the image forming unit 300 is shown in FIG. 11. As shown in this figure, in the image forming unit 300, unfixed toner remains on the paper from the position (PA16) where it contacts the transfer belt 335 until it leaves the fixing unit 336. Therefore, even if the paper is removed in this state, it cannot be reused. Therefore, by transporting the paper to position PA17 where it leaves the fixing unit 336, the paper becomes fused and can be reused. Therefore, if there is paper upstream of the fixing unit 336 when the print job is stopped, the paper is transported to PA17 before being stopped.

In this case, the flow of the paper transport control process by the transport control unit 962 that receives the transport stop signal during the print job stop process is shown in Figure 12 (a).

When the transport control unit 962 receives the transport stop signal, it determines whether or not there is paper in the image forming unit 300 (step S2201). If there is no paper, it stops transporting the paper (step S2204) and ends the process.

On the other hand, if it is within the image forming unit 300, its position is identified. Then, it is determined whether it is before (upstream from) the fixing unit 336 (step S2202). If it is downstream from the fixing unit 336, the process proceeds directly to step S2204, and the process ends.

If the paper is located upstream of the fixing unit 336, the paper is transported to the fixing unit 336 (step S2203), and the process proceeds to step S2204, where it ends.

In this way, according to this modified example, after the paper is transported to the exit of the image forming unit 300, the paper transport is stopped. This makes it possible to avoid the paper stopping in the image forming unit 300 before the toner is fixed. In other words, the paper can always be stopped in a state after the toner is fixed, making the paper reusable. This makes it possible to reduce waste due to transport stops.

<Modification 4>
The destination of the paper is not limited to position PA17 after the fixing unit 336. For example, the paper may be transported to a purge unit 339 (see FIG. 11 ) provided in the image forming unit 300. The purge unit 339 is configured to store paper that is no longer needed during image formation processing in the image forming unit 300. The purge unit 339 is located at the rear end of the image forming unit 300, and is a device that can accumulate paper in the image forming unit 300 without sending it to the post-processing device 200 from the image forming unit 300 when a paper jam occurs or when blank paper is discharged.

As with the previous variant, this means that the toner is fixed onto the paper and it can be reused.

<Modification 5>
Furthermore, in the print job stop process, the transport control unit 962 that receives the transport stop signal may transport the paper to the entrance of the post-processing unit 201 that cannot accept the paper.

For example, if a jam is detected in the stacker 280 but no abnormality is detected in the other post-processing units 201, the transport control unit 962 controls the transport of the paper to just before the stacker 280, i.e., to the exit of the ring binding unit 270, and stops it there.

In addition, during the recovery preparation operation of a print job that was interrupted due to the stacker 280, a jam may be detected in another post-processing unit 201. In such a case, the post-processing unit 201 in which the jam was detected is the post-processing unit 201 that cannot be accepted. In addition, multiple post-processing units 201 may be in an unacceptable state.

Therefore, when the transport control unit 962 receives a transport stop signal, it refers to the configuration information table 971 and identifies the most upstream post-processing unit 201 among the post-processing units 201 whose status is unacceptable. Then, it controls the paper to stop just before the identified post-processing unit 201 (for example, at the entrance of the post-processing unit 201).

In this case, the flow of the paper transport control process by the transport control unit 962 that receives the transport stop signal during the print job stop process is shown in Figure 12 (b).

First, the transport control unit 962 identifies the most upstream post-processing unit 201 among the post-processing units 201 that cannot accept paper (step S2301).

The transport control unit 962 transports the paper to just before (the entrance of) the identified post-processing unit 201 that cannot accept the paper (step S2302).

Then, paper transport is stopped (step S2204), and processing ends.

According to this modified example, if an abnormality such as a jam is detected before the post-processing device 200 is ready to start up, the paper is transported to the front of the unreceived post-processing unit 201. This allows post-processing to be performed immediately when the post-processing unit 201 is ready to return to normal, thereby shortening the total print job time.

<Modification 6>
When an abnormality is detected and a print job stop process is performed, operation in the image forming unit 300 is also stopped. Therefore, when the print job is subsequently resumed, a start-up process for the image forming unit 300 must also be performed. The start-up process includes, for example, a pre-print refresh operation for each number of prints. This start-up process is a process independent of the post-processing device 200.

To shorten this time, for example, when a print job is stopped by the print job stop process, the startup process may be started immediately after. This allows the image forming unit 300 to proceed with preparations while the post-processing unit 201 that output the abnormality signal is performing recovery preparation processing.

The process flow in this case is shown in FIG. 13. As in the above modification, if an abnormality occurs, the process goes as far as the print job stop process in step S2104. That is, the print control unit 961 receives a print stop signal and interrupts the print job. Then, immediately after, the print control unit 961 starts the start-up process (step S2401) and ends the process.

When the print job stop process is performed, the warming process of the fixing unit 336 is also stopped. This causes the temperature of the fixing unit 336 to drop, and rewarming is required to resume printing. For example, this warming process (heating process) of the fixing unit 336 may be started immediately after the print job is stopped, as in the start-up process. In this case, too, the waiting time at the time of restarting can be shortened by the time it takes for the heating process of the fixing unit 336.

<Modification 7>
In the above embodiments and modified examples, the cause of interrupting a print job has been described as being the removal of paper from the stacker 280, but the cause of interruption is not limited to this. For example, the cause of interruption may be the refilling of staples in the finisher 290. Also, the cause may be the release of a jam in any of the post-processing units 201.

The correspondence table (table) in the specification may be generated by the learning effect of machine learning. For example, information stored in data tables referenced by the required time calculation unit 964, such as the transport time table 972 and the return time table 973, may be machine-learned based on information from a sensor capable of acquiring these data, and the accuracy of these data may be improved while the image forming apparatus 100 is in operation, thereby making it unnecessary to use these correspondence tables. Here, machine learning is a technology for making a computer acquire human-like learning capabilities, and refers to a technology in which a computer autonomously generates an algorithm required for judgment such as data identification from learning data that is previously captured, and applies this to new data to make predictions. The learning method for machine learning may be any of supervised learning, unsupervised learning, semi-supervised learning, reinforcement learning, and deep learning, or may be a combination of these learning methods. Any learning method for machine learning may be used.

Each function of the above-described embodiments can be realized by one or more processing circuits. In this specification, the term "processing circuit" includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and devices such as an ASIC (Application Specific Integrated Circuit), DSP (digital signal processor), FPGA (field programmable gate array), and conventional circuit modules designed to execute each function described above.

100: image forming apparatus,
200: post-processing device, 201: post-processing unit, 240: paper cooling unit, 250: inserter, 260: folding unit, 270: ring binding unit, 280: stacker, 281: tray, 282: dolly, 283: door, 284: switch, 285: cart, 286: tray position sensor, 287: dolly sensor, 288: door sensor, 289: jam detection sensor, 290: finisher,
300: image forming unit, 331: paper feed tray, 335: transfer belt, 336: fixing unit, 339: purge unit,
400: large capacity paper feed section, 410: large capacity paper feed unit, 411: connection unit, 420: large capacity paper feed unit,
901: CPU, 902a: ROM, 902b: RAM, 906: ASIC, 908: HDD controller, 910: controller, 920: short-distance communication circuit, 920a: short-distance communication I/F, 921: AGP bus, 922: PCI bus, 930: engine control unit, 931: scanner unit, 932: printer unit, 940: operation panel, 940a: panel display unit, 940b: operation panel unit, 950: network I/F, 961: print control unit, 962: transport control unit, 963: monitoring unit, 964: required time calculation unit, 965: resume time setting unit, 966: abnormality detection unit, 971: configuration information table, 972: transport time table, 973: recovery time table,
T0: time when the close signal is received, Ta: image creation preparation time, Te: third transport time, Tf: first transport time, Tm: monitoring period, Tp: print transport time, Ts: return preparation time, Ts': return preparation time, Tw: second transport time,

JP 2005-321482 A

Claims (10)

An image forming apparatus that executes a print job to form an image on a sheet-like medium,
an image forming unit that forms an image on the medium;
a paper feed unit that supplies the medium to the image forming unit;
a post-processing unit that performs post-processing on the medium supplied from the image forming unit;
a conveyance control unit that, after the print job is interrupted due to an operation in the post-processing unit, supplies the medium to a predetermined supply position when a recovery preparation time for the cause unit, which is the post-processing unit on which the operation was performed, has elapsed;
a print control unit that performs image creation preparation so that the transport control unit can control the medium to the supply position,
the print control unit starts the image formation preparation at a print job restart time calculated based on a length of a conveyance path of the paper feed unit connected to the image forming unit;
The image forming apparatus according to claim 1, wherein the supply position is an entrance of the post-processing section. 2. The image forming apparatus according to claim 1,
The print job restart time is further calculated based on a length of a transport path to the cause unit,
The image forming apparatus according to claim 1, wherein the supply position is an entrance of the conveying unit. 3. The image forming apparatus according to claim 1,
The image forming apparatus according to claim 1, wherein the recovery preparation time is calculated based on information notified from the causing unit. 4. The image forming apparatus according to claim 1,
the image forming unit, the paper feed unit, and the post-processing unit each include an abnormality detection sensor that outputs an abnormality signal when an abnormality is detected;
The image forming apparatus, wherein the transport control unit stops transport of the medium when the abnormality signal is received within the recovery preparation time after the print control unit resumes the print job. 5. The image forming apparatus according to claim 4,
When the transport control unit receives the abnormality signal, if the medium is present in the image forming unit, the transport control unit transports the medium to an exit of the image forming unit. 6. The image forming apparatus according to claim 5,
Each post-processing unit outputs an unacceptable signal when the medium is unacceptable;
the transport control unit further transports the medium in the image forming unit to immediately before an entrance of the post-processing unit that has output the disable signal. 5. The image forming apparatus according to claim 4,
the image forming unit includes a purge unit at a rear end thereof for accommodating unnecessary media;
When the transport control unit receives the abnormality signal, if the medium is present in the image forming unit, the transport control unit transports the medium to the purge unit. 8. The image forming apparatus according to claim 4,
The image forming apparatus according to claim 1, wherein the print control unit starts a start-up process for the image forming unit immediately after the transport control unit stops transport of the medium. 9. The image forming apparatus according to claim 8,
the image forming unit further includes a fixing unit that heats the medium onto which the toner has been transferred to fix the toner to the medium;
The image forming apparatus according to claim 1, wherein the start-up process includes heating the fixing unit. An image forming apparatus includes an image forming section that forms an image on a sheet-like medium, a paper feed section that supplies the medium to the image forming section, and a post-processing section that has a post-processing unit that performs post-processing on the medium supplied from the image forming section, the image forming apparatus being provided with a computer,
a transport control means for supplying the medium to a predetermined supply position when a recovery preparation time for the post-processing unit, which is the cause unit where the operation was performed, has elapsed after a print job is interrupted due to an operation in the post-processing unit;
a print control means for performing image creation preparation so that the transport control means can control the medium to the supply position;
the print control means starts the image creation preparation at a print job restart time calculated based on a length of a conveyance path of the paper feed unit connected to the image forming unit;
The supply location is an entrance to the post-processing section.