JP2005080267A - Serial communications control system, and serial communication control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of wrinkles, folds, tensions or the like of a recording paper in a peripheral device and to improve print quality by preferentially applying communication control to a timing-critical signal. <P>SOLUTION: It is decided whether it is necessary to output a predetermined sequence control signal for any one of a plurality of slave computers and when it is decided that the output is required, a predetermined monitoring order is changed. On the basis of the kind of the events monitored in the changed monitoring order, an output timing of the predetermined sequence control signal outputted from a main computer to the plurality of slave computers is corrected, so that the deviation of control timings between slave computers is suppressed to a minimum. Thus, the wrinkles, folds, tension and the like do not occur in the recording paper. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control system for serial communication performed between a main computer and a plurality of slave computers, and in particular, periodically monitors events occurring in the slave computers in a predetermined monitoring order, and The present invention relates to a serial communication control system that performs the sequence control.

In a copying machine which is an example of an image forming apparatus, an engine control unit which controls a mechanism of a sheet conveyance and development process, a paper feeding device, an automatic document conveying device or a finisher (post-processing device) provided in the copying machine. By performing serial communication between the engine control unit and the unit control unit via a common serial line connected to a plurality of unit control units that control each optional device such as The engine control unit outputs a control signal to the unit control unit and causes a plurality of unit control units to execute control of a plurality of optional devices to control the copying operation of the copying machine as a whole. In this way, a control method for controlling communication via a serial line is generally called a serial communication control method.
In the conventional serial communication control method, an event such as a processing request or a transmission request from the slave CPU to the master CPU is performed by the master CPU included in the engine control unit with respect to the slave CPUs included in the plurality of unit control units. A system (called a polling system) is used to check whether there is any one by one. Specifically, there is an event such as the above processing request in accordance with a predetermined order (polling order) at a predetermined time interval (polling interval) from one main CPU to other slave CPUs. A process for sequentially checking whether or not (hereinafter referred to as “polling process”) is performed. At this time, when the master CPU executes the sequence control for each slave CPU, the option unit having the slave CPU is output by outputting a control signal such as a command, a signal, or data to the slave CPU according to the polling order. Be controlled.
On the other hand, in Patent Document 1, the main CPU of the image recording apparatus main body and the slave CPUs of a plurality of additional devices connected to the main body are connected by a serial line to transmit time-division multiplexed data. The technology regarding the serial communication control method which performs is published. In Patent Document 2, the engine control unit of the printer main body and a plurality of control units that control each of the plurality of optional devices are connected by a serial interface circuit unit, and asynchronous transmission at an arbitrary timing from each option device. An optional device control device has been proposed that enables the reduction of processing load on the engine control unit.
Japanese Patent Laid-Open No. 7-82283 Japanese Patent Laid-Open No. 7-32705

Here, a case where image data of a plurality of documents set on the automatic document feeder 200 of the digital copying machine X shown in FIG. 1 is continuously copied will be considered. As shown in the schematic cross-sectional view of FIG. 1, the copying machine X includes a copying machine body 100 and an image scanner device 300 (hereinafter referred to as “scanner device 300”) provided above the copying machine body 100. And an automatic document feeder 200 (hereinafter referred to as “ADF 200”) provided on the upper surface of the copying machine main body 100 and a sheet on the side surface of the copying machine main body 100 after the copying process is discharged. The finisher 400 (post-processing apparatus) provided on the side of the printer and the first to third paper feeders 110 to 130 provided below the copying machine main body 100 are configured. The copying machine main body 100 is provided with an engine control unit 101 (see FIG. 2) for controlling an optional device such as the ADF 200 to control the copying operation of the copying machine X. Each of the optional devices includes a respective optional device. Is provided with a unit controller (see FIG. 2).
When the continuous copying operation is executed, for example, the recording paper is continuously taken out from the third paper feeding device 130 and sequentially sent out to the recording paper conveyance path. A plurality of recording sheets are conveyed downstream in the conveying direction in cooperation with the first to third conveying rollers (116, 126, 136) in the recording sheet conveying path. When the conveyed recording paper reaches the registration roller 103, a paper detection sensor provided in front of the registration roller 103 is activated and a paper detection signal is output to the engine control unit 101. Based on this paper detection signal, the recording paper is temporarily stopped by the registration roller 103 in order to synchronize the leading edge of the toner image formed on the surface of the photosensitive drum 104a with the leading edge of the conveyed recording paper. In this case, since it is necessary to stop not only the registration roller 103 but all the conveyance rollers, the engine control unit 101 controls unit control units (first to third units) that control the first to third conveyance rollers. A stop control signal for stopping the transport operation of the transport roller. Based on the conventional serial communication control method, the engine control unit 101 sends, for example, a polling order L ₀ (ADF200⇒finisher 400⇒scanner device 300⇒first supply) to the unit control unit such as the paper feed control unit. Paper device 110 → second paper feeding device 120 → third paper feeding device 130 → ADF 200). At this time, if the paper detection signal is detected immediately after the polling process is performed on the first paper feeding device, the stop control signal is sent to the second paper feeding device in the next order according to the order L _0. 120 and the third sheet feeder 130 are output in this order. The stop control signal for stopping the transport operation of the transport roller 116 is output to the first paper feed controller 111 (FIG. 2) because the polling process is performed by the second paper feeder 120 from the polling order. When the polling process is executed again according to L _{0 and} the first sheet feeding device 110 is executed again, that is, after the polling process is completed, the second sheet feeding control unit 121 is executed. A stop control signal is output to the first paper feed control unit 111 after [polling interval × number of optional devices] time after the stop control signal is output. That is, since the stop control signal output from the engine control unit 101 to the paper feed control unit is output after being delayed by the [polling interval × number of optional devices] time, the timing at which each transport roller is stopped. There will be a time lag of the maximum [polling interval x number of optional devices]. This misalignment may cause the second and third transport rollers to stop even though the first transport roller is driven, and the paper in the paper transport path may be pulled and the paper may be stretched. There is. If an image is formed on such a sheet, the printing position may be misaligned, and the printing quality is deteriorated.
On the other hand, when the transport roller that has been temporarily stopped is restarted, the start control signal for restarting the transport operation of the transport roller immediately after the polling process is performed on the first paper feeder is in the above order. When the second sheet feeding device 120 and the third sheet feeding device 130 are output in order in accordance with L ₀ , the conveying operation of the conveying roller 116 is restarted with respect to the first sheet feeding control unit 111. The activation control signal is output because the polling process is sequentially performed from the second sheet feeding device 120 according to the polling order L _{0 and the} polling process is performed again on the first sheet feeding apparatus 110. That is, after the polling process is completed. In this case as well, as in the case where the stop control signal is output, the first feeding is performed after [polling interval × number of optional devices] time after the start control signal is output to the second paper feed control unit 121. A start control signal is output to the paper control unit 111. As a result, the start control signal output from the engine control unit 101 to the paper feed control unit is [polling interval × number of optional devices]. Since the output is delayed by the time, the maximum [polling interval × number of optional devices] time shift occurs at the timing of starting each transport roller. This misalignment causes a phenomenon in which the second and third transport rollers 126 and 136 are activated even though the first transport roller 116 is stopped, and the paper in the paper transport path is pressed and applied to the paper. There is a risk of wrinkles and breakage. If an image is formed on such a sheet, the printing position may be misaligned. In this case as well, the printing quality deteriorates, which is a problem.
Further, the deviation in the control timing not only applies unnecessary load to the drive motor that rotates the conveyance roller to shorten the life of the drive motor, but also causes abnormal noise of the drive motor, which is uncomfortable for the user. This is a problem.

Such a problem can be solved, for example, by performing parallel communication control using a parallel line provided separately with a timing critical signal such as a control signal for stopping or starting the conveyance roller. The advantage of saving wiring by serial communication is lost, which is not preferable. It is also conceivable to perform serial communication control with a serial line only for timing critical control objects, but this also increases the number of control lines and reduces the merit of reduced serial communication wiring. To do.
In addition, a high-frequency, high-performance CPU is provided in the engine control unit and the unit control unit that controls the optional device to shorten the polling interval, thereby shortening the polling cycle (the time spent for the entire polling process). Thus, it is conceivable to shorten the timing deviation to such an extent that the above problem does not occur. Also, if the polling cycle is shortened too much, the processing speed other than the polling process is reduced, which may cause a new problem.
Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to cause the above-mentioned problem that occurs in an option unit or a peripheral device by preferentially controlling communication of a timing critical signal such as a control signal. It is an object of the present invention to provide a serial communication control system and a serial communication control program that can solve the problem.

  In order to achieve the above object, according to the present invention, a main computer performs serial communication with a plurality of slave computers, and events generated by the main computer in the slave computers are periodically performed in a predetermined monitoring order. In a serial communication control system that performs predetermined sequence control on the slave computer and determines whether it is necessary to output a predetermined sequence control signal for any of the plurality of slave computers The main computer is caused to execute a determination procedure and a sequence change procedure for changing the monitoring sequence when it is determined that a predetermined sequence control signal needs to be output by the determination procedure. Configured as a serial communication control system To have. As a result, it is possible to minimize the deviation of the control timing generated between the slave computers.

Here, the main computer is an engine control device of the image forming apparatus, and the plurality of slave computers are configured to include a plurality of transport rollers that perform a transport operation of holding and feeding a sheet to at least the image forming unit of the image forming apparatus. A serial communication control system which is a unit control device of an optional unit of the image forming apparatus to be controlled, wherein the determination procedure controls the plurality of transport rollers performing the transport operation in a state where the sheet is sandwiched. The controller determines whether or not it is necessary to output a stop control signal for stopping the plurality of transport rollers or a start control signal for restarting the plurality of transport rollers stopped by the stop control signal. It is possible that there is.
In this case, when it is determined that the order change means needs to output the stop signal according to the determination procedure, the transport roller on the downstream side in the paper transport direction by the transport operation moves upstream in the paper transport direction. It is desirable that the monitoring order is changed in the order in which the conveying rollers are arranged facing toward each other. As a result, it is possible to minimize the difference in the stop timing between the plurality of transport rollers, and it is possible to eliminate the deterioration in print quality caused by the pulling of the paper, which has conventionally occurred.
Further, in this case, when it is determined that the order change means needs to output the start signal according to the determination procedure, the upstream side transport roller in the sheet transport direction by the transport operation is downstream of the sheet transport direction. It is desirable that the monitoring order is changed in the order in which the conveying rollers arranged toward the side are arranged. As a result, it is possible to minimize the difference in the start timing between the plurality of transport rollers, and it is possible to eliminate the deterioration of the print quality caused by the paper wrinkles or folds, which has conventionally occurred.

  Further, the main computer may monitor an event that has occurred in the slave computer by a polling method.

The present invention may also be understood as a serial communication control program that causes the main computer to execute each procedure of the serial communication control system. That is, the main computer performs serial communication with a plurality of slave computers, and the main computer periodically monitors events generated in the slave computers in a predetermined monitoring order. A determination procedure for determining whether or not it is necessary to output a predetermined sequence control signal to any of the plurality of slave computers, which is a program executed in a serial communication control system that performs predetermined sequence control on a computer And a sequence communication control program for causing the main computer to execute a sequence change procedure for changing the monitoring sequence when it is determined that a predetermined sequence control signal needs to be output by the determination procedure. Even if it was captured It is possible to solve the serial problems.
Can. In this case, the main computer is an engine control device of the image forming apparatus, and the plurality of slave computers are configured to include a plurality of transport rollers that perform a transport operation that sandwiches and feeds paper to at least the image forming unit of the image forming apparatus. It is a unit control device of an optional unit of the image forming apparatus to be controlled, and the optional unit is preferably a paper feeding unit or a paper transport device for transporting recording paper.

As described above, according to the present invention, an event occurring in a slave computer is periodically monitored in a predetermined monitoring order, and a plurality of slave computers are connected in a serial communication control system that performs a predetermined sequence control. It is determined whether or not it is necessary to output a predetermined sequence control signal, and when it is determined that the necessity has occurred, the monitoring order is changed, and the monitoring is performed in the changed monitoring order. Based on the type of event, the output timing of a predetermined sequence control signal output from the main computer to the plurality of slave computers is corrected, so that the control timing deviation between the slave computers is minimized. It becomes possible.
Further, the main computer is an engine control device of the image forming apparatus, and the plurality of slave computers control a plurality of transport rollers that perform a transport operation of holding and feeding a sheet to at least the image forming unit of the image forming apparatus. In the case of a serial communication control system, which is a unit control device of an optional unit of the image forming apparatus, the unit control device that controls the plurality of transport rollers that perform the transport operation while sandwiching the sheet. It is determined whether it is necessary to output a stop control signal for stopping a plurality of transport rollers or a start control signal for restarting the plurality of transport rollers stopped by the stop control signal. When it is determined that there is a need to output, the above monitoring sequence is the paper by the above transport operation. Since the order of arrangement of the conveyance rollers arranged from the conveyance roller at the most downstream side in the feeding direction toward the upstream side in the sheet conveyance direction is changed, the difference in stop timing between the plurality of conveyance rollers can be minimized. This makes it possible to eliminate the deterioration in print quality caused by the pulling of the paper, which has conventionally occurred.
Furthermore, when it is determined that it is necessary to output the start control signal, the monitoring order is arranged from the most upstream conveying roller in the sheet conveying direction by the conveying operation toward the downstream side in the sheet conveying direction. In addition, since the order of the transport rollers is changed, it is possible to minimize the difference in the start timing between the plurality of transport rollers, and to eliminate the deterioration in print quality caused by paper wrinkles or folds that has occurred in the past. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a schematic sectional view of a digital copying machine X to which a serial communication control system according to an embodiment of the present invention is applied. FIG. 2 is an application of the serial communication control system according to the embodiment of the present invention. Connection diagram showing an example of serial line connection of digital copying machine X, FIGS. 3 and 4 are polling executed by the engine control unit of digital copying machine X to which the serial communication control system according to the embodiment of the present invention is applied. It is a flowchart explaining the procedure of a process.

First, an outline of the configuration of a digital copying machine X (hereinafter referred to as “copying machine X”) to which a serial communication control system according to an embodiment of the present invention is applied will be described with reference to the sectional view of FIG. To do. Note that the copying machine X is merely an example of an image forming apparatus, and other examples of the image forming apparatus to which the serial communication control system is applied include a facsimile machine, a printing machine, and a printer apparatus.
As shown in FIG. 1, the copying machine X has a copying machine main body 100 and an image scanner device 300 (hereinafter referred to as “scanner device 300”) provided above the copying machine main body 100 as described above. And an automatic document feeder 200 (hereinafter referred to as “ADF 200”) provided on the upper surface of the copying machine main body 100 and a sheet on the side surface of the copying machine main body 100 after the copying process is discharged. The finisher 400 (post-processing apparatus) provided on the printing machine side, and the sheet feeding apparatuses 110 to 130 provided below the copying machine main body 100 are configured.
The ADF 200 is provided in the document transport path, a document set section 205 for setting a plurality of documents, a document feed roller 210 that sequentially feeds the documents set in the document set section 205 to the document transport path one by one. , A front side reading unit 203 made of a CCD or CMOS for reading image data on the front side of the document conveyed by a plurality of conveyance rollers 213, a back side reading unit 204 for reading image data on the back side of the document, and a document discharging unit A document discharge roller 215 for discharging to 216 and an ADF control unit 201 (see FIG. 2) for controlling the operation of each unit of the ADF 200 are provided.
The scanner device 300 includes an exposure device (not shown) that scans and exposes a document surface set on a document table, and mirrors 310 a, 310 b, and 310 c that guide irradiation light irradiated on the document surface to an optical lens 311 and a CCD 312. And the optical lens 311 for condensing the reflected light, and the reflected light collected by the optical lens 311 is received to convert the image information contained in the reflected light into an electrical signal that can be recognized by the copying machine X. A CCD 312 and a scanner control unit 301 (see FIG. 2) for controlling the operation of each unit of the scanner device 300 are provided.
The finisher 400 is a device that discharges the sheet conveyed from the copying machine main body 100 to a predetermined discharge tray 320. For example, when the sort function is selected, the finisher control unit 401 (see FIG. 2) sorts the sheet after image formation conveyed from the copying machine main body 100 and discharges it to a predetermined discharge tray 420.
The first paper feeder 110 includes a paper cassette 113 for stacking a plurality of papers, a pickup roller 114 for picking up the paper in the paper cassette 113, and a paper feeding unit for feeding the paper taken out by the pickup roller 114 to the paper transport path. A paper roller 115, a transport roller (feed roller) 116 that transports the paper in the paper transport path downstream in the transport direction, and a first paper feed control unit 111 that controls the operation of each part of the paper feeding device 110 (see FIG. 2). Further, below the paper feeding device 110, the second paper feeding device 120 having the same configuration as the first paper feeding device, including the second paper feeding control unit 121, and a third paper feeding device is provided. A third paper feeder 130 having a paper feed controller 131 is sequentially arranged.

  The copying apparatus main body 100 is conveyed from the photosensitive drum 104a, the charging device 104b, the exposure device (not shown), the developing device 104c, the transfer device 104d, the cleaning device 104e, and the like, and the paper feeding device. The registration roller 103 that temporarily stops the generated paper and feeds the paper in synchronization with the leading edge of the toner image formed on the surface of the photosensitive drum 104a and the leading edge of the paper, and the downstream side in the conveyance direction of the registration roller 103 The scanner device 300, the ADF 200, and the finisher are controlled by controlling a sheet detecting sensor (not shown) provided in the image forming apparatus, a fixing device 105 for fixing the toner image transferred onto the sheet to the sheet, and the copying machine main body 100. 400, each control unit for controlling optional units such as the first to third sheet feeding devices 110 to 130. Parts (hereinafter, collectively referred to as. "Unit controller") is constituted by an engine control unit 101 for outputting a control signal if necessary respect (see Figure 2). Furthermore, a program ROM 103 storing a serial communication control program, which will be described later, and a master CPU 102 are provided. The serial communication control program has a determination function and a sequence change function realized by the master CPU 102 reading from the program ROM 103 and executing arithmetic processing.

Here, the determination function and order change function of the serial communication control program will be described.
The determination function is a function for causing the main computer to execute a determination procedure for determining whether it is necessary to output a predetermined sequence control signal for any of the plurality of slave computers. Specifically, the main computer is the engine control unit 101 of the image forming apparatus, and the plurality of slave computers perform a plurality of conveying operations for holding and feeding paper at least to the image forming unit of the image forming apparatus. In the case of the unit control unit of the optional unit of the image forming apparatus that controls the conveyance roller, the plurality of conveyance units with respect to the unit control unit that controls the plurality of conveyance rollers that perform the conveyance operation with the sheet held therebetween. It is determined whether or not it is necessary to output a stop control signal for stopping the rollers or a start control signal for restarting the plurality of transport rollers stopped by the stop control signal. The stop control signal is output by the engine control unit 101 based on, for example, a paper detection signal output by a paper detection sensor provided on the downstream side of the registration roller 103 in the transport direction.

  The order change function refers to an order change procedure for changing a predetermined monitoring order when it is determined that it is necessary to output a predetermined sequence control signal such as the stop control signal or the start control signal by the determination procedure. This function is executed by a main computer such as the engine control unit. Specifically, when it is determined that the stop control signal needs to be output by the determination procedure (for example, when the engine control unit 101 detects the sheet detection signal), the sheet transport direction by the transport operation is determined. The monitoring order is changed in the arrangement order of the conveying rollers arranged from the most downstream conveying roller toward the upstream side in the sheet conveying direction. In addition, when it is determined that the start control signal needs to be output by the determination procedure, it is disposed from the most upstream side conveyance roller in the sheet conveyance direction by the conveyance operation toward the downstream side in the sheet conveyance direction. The monitoring order may be changed in the order in which the conveying rollers are arranged.

Next, a serial line connection between the engine control unit 101 and a unit control unit that controls each option unit constituting the copying machine X will be described with reference to a connection diagram of FIG.
The engine control unit 101 and the unit control unit are connected by a serial line L1 and a serial line L2. The serial line L1 is a serial cable that transmits a control signal from the engine control unit 101 to the plurality of unit control units, and the serial line L2 is connected from the plurality of unit control units to the engine control unit 101. It is a serial cable that transmits a processing request signal. Note that the processing request signal is an example of an event signal, and is not particularly limited thereto. For example, a stop request flag or a stop request bit enabled on the unit control unit side may be used as the event signal. Specifically, an error signal output when an error such as a paper jam occurs corresponds to an event signal.
With this connection, the main computer such as the engine control unit 101 performs serial communication with slave computers such as the unit control units, and the engine control unit 101 controls the plurality of unit controls. In accordance with the polling order (monitoring order) L ₀ (ADF 200 ⇒ finisher 400 ⇒ scanner device 300 ⇒ first sheet feeder 110 ⇒ second sheet feeder 120 ⇒ third sheet feeder 130 ⇒ ADF 200). , And periodically performing polling processing at intervals of 10 ms, and predetermined sequence control for the plurality of unit control units is executed based on the processing request signal detected by the polling processing.

Next, an example of a polling process executed by the engine control unit 101 of the copying machine X will be described with reference to the flowcharts of FIGS. In the figure, S100, S110... Indicate processing procedure (step) numbers. The process starts from step S100.
When the power of the copying machine X is turned on, initialization of polling processing is executed in step S100. Specifically, the polling destination where the polling process is executed first is ADF200 (P ₁ : ADF200), and the polling order is the normal order L ₀ (ADF200 → finisher 400 → scanner apparatus 300 → first sheet feeder 110 → The second paper feeding device 120 → the third paper feeding device 130 → the ADF 200) is set to have a polling interval of 10 ms.
Subsequently, in step S101, the engine control unit 101 determines whether it is time to output a control signal such as a stop control signal or a start control signal, that is, whether it is necessary to output a control signal. Specifically, a stop control signal for stopping all the transport rollers in order to temporarily stop the paper transport operation in the registration roller 103, or restart all the transport rollers in order to restart the temporarily stopped paper transport operation. It is determined whether or not it is time to output a start / stop signal. If it is determined that it is not time to output the control signal, the process proceeds to step S102. If it is determined that it is time to output the control signal, the process proceeds to step S110 of the flowchart shown in FIG. Whether or not it is the timing to output the stop control signal is determined based on a paper detection signal from a paper detection sensor or the like that detects that the paper has reached the registration roller 103.

In the process that proceeds to step S110 of the flowchart shown in FIG. 4, it is first determined whether or not the control signal output from the engine control unit 101 is the stop control signal. If it is determined that the control signal is not a stop control signal, it is determined in step S112 whether the control signal output by the engine control unit 101 is a start control signal.
If it is determined in step S110 that it is a stop control signal, in step S111, the polling destination is set in the first paper feeding device 110 (P ₄ : first paper feeding device), and then shown in FIG. It progresses to step S102 of a flowchart.
If it is determined that at step S112 is a start control signal, in step S113, polled the third sheet feeding device 130: Set to (P ₆ third sheet feeding device), followed by the polling order in step S114 Is set in the order from the forward order L ₀ to the reverse order L ₁ (ADF 200 → third paper feeding device 130 → second paper feeding device 120 → first paper feeding device 110 → scanner device 300 → finisher 400 → ADF 200). Specifically, the processing in step S114 is executed by selecting data indicating reverse order L ₁ from two types of order data indicating normal order L ₀ and reverse order L ₁ stored in advance. When polling order is set in the reverse order L ₁ in step S114, followed by the process proceeds to step S102 of the flowchart shown in FIG. The processing procedure in steps S110, S111, and S112 is an example of the determination procedure. The processing procedure in step S114 is an example of the order change procedure.

When the process proceeds to step S102 in the flowchart shown in FIG. 3, the engine control unit 101 determines whether the order of the polling process is the forward order L ₀ or the reverse order L ₁ .
If it is determined to be set to the normal order L ₀ is in step S102, firstly, a polling process is executed for polled P _k in step S103. When the polling process of P _k ends in step S103, it is subsequently determined in step S104 whether there is a next polling destination P _{k + 1} (next node P _{k + 1} ). If it is determined that there is no next polling destination P _{k + 1} , the polling destination is set to P ₁ in step S107, and then the process returns to step S101, and a series of polling processes are executed again. If it is determined that there is the next polling destination P _{k + 1} , the polling destination is set to P _{k + 1} after the polling interval of 10 ms is counted, and in step S104, the next polling destination P _{k + 1 is set.} The closed loop processing from step S103 to S106 is repeatedly executed until it is determined that there is no data.
If the polling destination is set in the first paper feeder 110 (P ₄ ) in step S111, the polling process is executed for the first paper feeder 110 (P ₄ ) in step S103. Subsequently, the polling process is executed in the order of the second paper feeding device 120 (P ₅ ) and the third paper feeding device 130 (P ₆ ). As described above, when it is determined that the stop control signal for stopping the transport roller is output, the polling destination is set in the first transport device 110 (P ₄ ) regardless of the polling order L _0. , Because the polling process is sequentially executed from the first transport device 110 (P ₄ ) in the normal order L ₀ , the difference in output timing of the stop control signal generated between the next paper feeding devices (shift in output timing) Is suppressed to a polling interval of 10 ms. As a result, the conventional recording paper is not pulled and the deterioration of the printing quality can be solved.

Then, if it is determined to be set in the reverse order L ₁ in step S102, firstly, a polling process is executed for polled P _k at step S120. When the polling process of P _k is completed in step S120, it is subsequently determined in step S121 whether there is a next polling destination P _k-1 (next node P _k-1 ). If it is determined that there is no next polling destination P _k−1 , the polling destination is set to P _n in step S124, and then the process returns to step S101, and a series of polling processes are executed again. If it is determined that there is the next polling destination P _k−1 , the polling destination is set to P _k−1 after the polling interval of 10 ms is counted, and in step S121, the next polling destination P _{k−1 is set.} The closed loop processing from step S120 to S123 is repeatedly executed until it is determined that there is no data.
Here, if the polling destination is set to the third paper feeding device 130 (P ₆ ) in step S113 and the polling order is set to the reverse order L ₁ in step S114, the third paper feeding device is set in step S120. Polling processing is executed for 130 (P ₆ ), and then polling processing is executed in the order of the second paper feeding device 120 (P ₅ ), the first paper feeding device 110 (P ₄ ),. . As described above, when it is determined that the start control signal for starting the transport roller is output, the polling order is set from the forward order L ₀ to the reverse order L ₁ , and the polling destination is the third transport device 130. Since (P ₆ ) is set and polling processing is sequentially executed in the reverse order L ₁ from the third transport device 130 (P ₆ ), the output timing of the activation control signal generated between the next paper feeding devices is determined. The difference (shift in output timing) is suppressed to a polling interval of 10 ms. As a result, there is no occurrence of wrinkling or folding of the recording paper, which has conventionally occurred, and the deterioration of the printing quality can be solved.

  In the above description of the embodiment, it has been described that the engine control unit 101 of the copying machine X monitors an event such as a processing request signal generated in each unit control unit that controls the option unit by the polling method. An embodiment in which an event occurring in each of the unit control units is monitored using an access method used in a LAN, a WAN, or the like may be used. For example, by the token passing method or the token ring method, the engine control unit 101 sends a specific frame called a token to a transmission line laid in a ring shape, and a processing request signal (event signal) is added by the unit control unit When the engine control unit 101 receives the token again, the engine control unit 101 may monitor the processing request signal. If the token passing method or token ring method is used, even if the transmission path is congested, the amount of attenuation of the processing speed is relatively small, so that a stable processing speed can be maintained, and a processing speed delay can be maintained. There is an advantage that the quantity can be predicted in advance.

1 is a schematic sectional view of a copying machine X to which a serial communication control system according to an embodiment of the present invention is applied. 1 is a connection diagram showing an example of serial line connection of a copying machine X to which a serial communication control system according to an embodiment of the present invention is applied. 6 is a flowchart for explaining a procedure of polling processing executed by the engine control unit of the copying machine X to which the serial communication control system according to the embodiment of the present invention is applied. 6 is a flowchart for explaining a procedure of polling processing executed by the engine control unit of the copying machine X to which the serial communication control system according to the embodiment of the present invention is applied.

Explanation of symbols

X ... Digital copier 100 ... Digital copier body 101 ... Engine control unit 104 ... Image forming unit 110 ... First paper feeder 120 ... Second paper feeder 130 ... Third paper feeder 113, 123, 133 ... Paper cassettes 116, 126, 136 ... Conveying rollers (feed rollers)
200 ... Automatic document feeder (ADF)
300 ... Image scanner device 400 ... Finisher (post-processing device)
420: paper discharge tray

Claims (7)

The main computer performs serial communication with a plurality of slave computers, and the main computer periodically monitors events generated in the slave computers in a predetermined monitoring order, and In a serial communication control system that performs predetermined sequence control,
A determination procedure for determining whether it is necessary to output a predetermined sequence control signal for any of the plurality of slave computers;
A sequence change procedure for changing the monitoring sequence when it is determined that the predetermined sequence control signal needs to be output by the determination procedure;
A serial communication control system, wherein the main computer is executed. The main computer is an engine control device of the image forming apparatus,
Serial communication control as a unit control device of an optional unit of the image forming apparatus that controls a plurality of conveying rollers that perform a conveying operation in which the plurality of slave computers sandwich and send a sheet to the image forming unit of the image forming apparatus A system,
The determination procedure is stopped by a stop control signal for stopping the plurality of transport rollers or the stop control signal for the unit control device that controls the plurality of transport rollers performing the transport operation in a state where the sheet is sandwiched. 2. The serial communication control system according to claim 1, wherein it is determined whether or not it is necessary to output an activation control signal for activating the plurality of conveying rollers again.   When it is determined that the order change means needs to output the stop signal according to the determination procedure, the order change unit is arranged from the transport roller on the most downstream side in the paper transport direction by the transport operation toward the upstream side in the paper transport direction. The serial communication control system according to claim 2, wherein the monitoring order is changed in the order in which the transport rollers are provided.   When it is determined that the order change means needs to output the start signal according to the determination procedure, the order changing unit is arranged from the transport roller on the most upstream side in the paper transport direction by the transport operation toward the downstream side in the paper transport direction. The serial communication control system according to claim 2, wherein the monitoring order is changed in the order in which the transport rollers are provided.   5. The serial communication control system according to claim 1, wherein the main computer monitors an event occurring in the slave computer by a polling method. The main computer performs serial communication with a plurality of slave computers, and the main computer periodically monitors events generated in the slave computers in a predetermined monitoring order, and A program executed in a serial communication control system that performs a predetermined sequence control,
A determination procedure for determining whether it is necessary to output a predetermined sequence control signal for any of the plurality of slave computers;
A sequence change procedure for changing the monitoring sequence when it is determined that the predetermined sequence control signal needs to be output by the determination procedure;
A serial communication control program for causing the main computer to execute the above. The main computer is an engine control device of the image forming apparatus,
A unit control device for an optional unit of the image forming apparatus, wherein the plurality of slave computers control a plurality of conveying rollers that perform a conveying operation of holding and feeding a sheet to at least an image forming unit of the image forming apparatus, The serial communication control program according to claim 6, wherein the optional unit is a paper feed unit or a paper transport device that transports the recording paper.

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