JP2019139135A - Image forming apparatus - Google Patents

Abstract

To prepare a plurality of transmission methods, prevent an increase in processing load on a control circuit, and prevent the time interval from a request for to completion of transmission of specific data from becoming longer than or equal to a certain time interval.SOLUTION: An image forming apparatus comprises: a timer; a first control circuit; and a second control circuit. The timer measures a monitoring period. The second control circuit is connected to a first object and a second object. The first control circuit generates first request data. The first control circuit transmits the first request data to the second control circuit as first control data by using a mailbox. The first control circuit generates second request data for controlling the second object. When the monitoring period newly starts, the first control circuit generates second control data based on the second request data and transmits the generated second control data to the second control circuit.SELECTED DRAWING: Figure 8

Description

  The present invention relates to inter-circuit communication in an image forming apparatus including a plurality of control circuits that perform communication.

  The image forming apparatus may include a plurality of control circuits. Various data may be exchanged between control circuits. An example of an image forming apparatus that exchanges status information between a print controller and an engine control unit is described in Patent Document 1.

  Patent Document 1 includes an engine control unit that controls a printer engine that prints on a sheet, and an image controller that outputs a command to the engine control unit to recognize the state of the printer engine. A status change notification signal for notifying the image controller that the status information has changed, and when the status information changes within a predetermined period, the printer engine has a predetermined priority order inside the printer engine. On the basis of this, there is described an image forming apparatus that selectively notifies a changed status information to an image controller and transmits a status change notification signal. An attempt is made to limit the number of state change information to be notified (Patent Document 1: Claim 1, paragraph [0087]).

JP 09-281852 A

  A plurality of control circuits may be provided in the image forming apparatus. The control circuit is, for example, a CPU. Each control circuit performs assigned processing. Communication is performed between the control circuits so that the entire image forming apparatus operates without any problem. For example, a control circuit may be provided in each of the main body of the image forming apparatus and an optional device attached to the image forming apparatus. The control circuit on the main body side gives an operation instruction to the control circuit of the optional device. The control circuit of the optional device controls members included in the optional device based on the operation instruction. Further, the control circuit of the main body of the image forming apparatus and the optional device notify each other of the state. The other party's status can be confirmed by mutual notification.

  When data communication is performed between the control circuits, there is not a little time interval (delay) from when the control circuit issues a data transmission request (after determining that data is transmitted) until the actual data transmission is completed. If this time interval becomes long, printing may be greatly affected. For example, the paper position may deviate greatly from the ideal position. The paper may not stop at the proper position. If the positional deviation of the paper is large, the paper may be jammed or the printing position may be shifted. In particular, in an image forming apparatus with a high printing speed, a sheet is conveyed at high speed. Therefore, the faster the image forming apparatus, the narrower the allowable time interval.

  For example, if data is transmitted as soon as a request is issued, the time interval from request to reception tends to be short. However, such data transmission frequently interrupts the transmission process during another process. The processing load (processing amount) of the control circuit increases. On the other hand, some data does not have a significant effect on printing even if the time interval is somewhat long. Therefore, there is a problem that the time interval from the request to the completion of transmission should be kept to a minimum for the data to be transmitted promptly while preventing the processing load of the control circuit from becoming too large.

  In the technique described in Patent Document 1, information to be notified is intentionally reduced, and state changes are transmitted efficiently. However, the communication method is constant, and the information transmission speed is fixed. If the amount of information to be transmitted increases and the data waiting to be transmitted increases, the transmission of information may be delayed, which may greatly affect the job to be executed.

  In view of the above problems, the present invention prepares a plurality of transmission methods and suppresses an increase in the processing load of the control circuit, while preventing a time interval from a transmission request to completion for specific data from exceeding a certain level. To.

  The image forming apparatus according to the present invention includes a timer, a first control circuit, a second control circuit, a first storage unit, and a second storage unit. The timer measures a predetermined monitoring period. The second control circuit communicates with the first control circuit. The second control circuit is connected to the first target and the second target. The second control circuit controls operations of the first object and the second object. The first storage unit stores first request data for controlling the first object. The second storage unit stores second request data for controlling the second object. The first control circuit generates the first request data based on control software. The first control circuit transmits the first request data as first control data to the second control circuit using a mailbox. The second control circuit controls the first object based on the received first control data. The first control circuit generates second request data for controlling the second target based on the control software. The first control circuit stores the generated second request data in the second storage unit. When the monitoring period newly starts, the first control circuit generates second control data based on the second request data stored in the second storage unit during the previous monitoring period. . The first control circuit transmits the generated second control data to the second control circuit. The second control circuit controls the second object based on the received second control data. The monitoring period is set to be shorter than the reference interval. The reference interval is an approximate time interval from the generation of the first request data to the actual transmission of the first control data to the second control circuit.

  According to the present invention, a plurality of transmission methods can be prepared for communication between control circuits. For specific control data that should not be delayed while reducing the processing load on the control circuit, the time interval from the request to the completion of transmission can be shortened.

1 is a diagram illustrating an example of an image forming apparatus according to an embodiment. 1 is a diagram illustrating an example of an image forming apparatus according to an embodiment. It is a figure which shows an example of the engine control part which concerns on embodiment. It is a figure which shows an example of the paper feeder which concerns on embodiment. It is a figure which shows an example of transmission of the 1st control data which concerns on embodiment. It is a figure which shows an example of transmission of the 2nd control data which concerns on embodiment. It is a figure which shows an example of the production | generation of the 2nd control data which concerns on embodiment. It is a figure which shows an example of the production | generation of the 2nd control data which concerns on embodiment. It is a figure which shows an example of transmission of the 3rd control data which concerns on embodiment. It is a figure which shows an example of transmission of the 3rd control data which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Hereinafter, the image forming apparatus 100 to which the optional device is attached will be described. The image forming apparatus 100 is of an ink jet type. For example, the image forming apparatus 100 can print 100 or more A4 sheets per minute. The image forming apparatus 100 may be an electrophotographic type. The image forming apparatus 100 will be described using a printer as an example. Note that the image forming apparatus 100 may be, for example, a multifunction peripheral. As an optional device, the sheet feeder 7 will be described as an example.

(Outline of image forming apparatus 100)
First, the outline of the image forming apparatus 100 according to the embodiment will be described with reference to FIGS. 1 and 2. 1 and 2 are diagrams illustrating an example of an image forming apparatus 100 according to the embodiment.

  The image forming apparatus 100 includes a control unit 1, a storage unit 2, an operation panel 3, an engine control unit 4, a printing unit 5, and a communication unit 6. The control unit 1 controls each unit of the image forming apparatus 100. The control unit 1 includes a CPU 11 and an image processing circuit 12. The CPU 11 performs calculation and processing based on the control program and control data stored in the storage unit 2. The storage unit 2 includes a nonvolatile storage device such as a ROM and storage (HDD, flash ROM), and a volatile storage device such as a RAM. The image processing circuit 12 performs image processing on image data used for printing.

  The image forming apparatus 100 includes an operation panel 3. The operation panel 3 includes a display panel 31 and a touch panel 32. The display panel 31 displays a setting screen and information. The display panel 31 displays operation images such as keys, buttons, and tabs. The touch panel 32 detects a touch operation on the display panel 31. Based on the output of the touch panel 32, the control unit 1 recognizes the operated operation image. The control unit 1 recognizes the setting operation performed by the user.

  The image forming apparatus 100 includes an engine control unit 4 and a printing unit 5. The printing unit 5 includes a paper feeding unit 5a, a paper feeding device 7, a paper conveying unit 5b, and an image forming unit 5c. When receiving a print execution instruction from the control unit 1, the engine control unit 4 controls the operation of the print unit 5 based on the print execution instruction. The paper feeding unit 5a is provided inside the main body. The sheet feeding unit 5a accommodates a sheet bundle. The paper feed unit 5 a includes a paper feed roller 51. The paper feed roller 51 is in contact with the uppermost paper in the paper feed unit 5a.

  The paper feeding device 7 is an optional device. The sheet feeding device 7 is attached to the right side surface of the main body portion 101 of the image forming apparatus 100. The paper feeding device 7 includes a plurality of paper cassettes 71. Each sheet cassette 71 accommodates a sheet bundle. One optional paper feed roller 72 is provided for each paper cassette 71. Each optional paper feed roller 72 is in contact with the top of the paper set in the paper cassette 71.

  In the case of a print job, the control unit 1 rotates any one of the paper feed roller 51 and the optional paper feed roller 72. The operation panel 3 accepts selection of paper feeding from the paper feeding unit 5 a or paper feeding from the paper feeding device 7. Further, using the computer 200 connected to the communication unit 6, it is possible to select whether the paper is fed from the paper feeding unit 5 a or the paper feeding device 7. The operation panel 3 also accepts selection of which paper cassette 71 from the paper feeding device 7 to feed paper. It is also possible to select from which paper cassette 71 of the paper feeding device 7 paper is fed using the computer 200 connected to the communication unit 6. Based on input to the operation panel 3 or communication through the communication unit 6, the control unit 1 recognizes a part to be fed. The control unit 1 notifies the engine control unit 4 of the part to be fed. The engine control unit 4 feeds paper from the notified part.

  The paper feeding device 7 includes an optional conveyance unit 73. The optional conveyance unit 73 includes an optional conveyance path 74 and an optional conveyance roller pair 75. For convenience, in FIG. 2, only one optional conveying roller pair 75 is denoted by a reference numeral. A plurality of optional conveyance roller pairs 75 are provided along the optional conveyance path 74. When paper is fed from the paper feeder 7, the engine control unit 4 rotates the optional transport roller pair 75. The paper fed from the paper feeding device 7 is carried into the main body. The conveyance path of the sheet feeding device 7 joins the conveyance path on the upstream side of the image forming unit 5c. As a result, the sheet fed from the sheet feeding device 7 is supplied to the image forming unit 5c.

  The paper transport unit 5b transports paper. In FIG. 2, the paper conveyance path is indicated by a bold line. A plurality of transport roller pairs 52 are provided along the transport path. For convenience, in FIG. 2, only one conveyance roller pair 52 is denoted by a reference numeral. The paper transport unit 5 b includes a transport unit 53. The transport unit 53 includes a drive roller 54, a plurality of driven rollers 55, and a transport belt 56. The conveyor belt 56 is wound around the driving roller 54 and each driven roller 55. During a print job, the engine control unit 4 rotates the transport motor during printing. The transport motor 59 rotates each transport roller pair 52. The transport motor 59 rotates each transport roller pair 52. During printing, the engine control unit 4 rotates the belt motor 510. The belt motor 510 rotates the driving roller 54. As a result, the paper supplied from the paper supply unit 5a or the paper supply device 7 is conveyed toward the image forming unit 5c. After printing in the image forming unit 5c, the engine control unit 4 causes the paper transport unit 5b to transport the paper to the discharge tray 57. The recorded (printed) paper is discharged out of the machine. The discharge tray 57 is attached to the upper right side of the image forming apparatus 100. The paper transport unit 5b includes a suction unit 58 (see FIG. 3). The adsorbing unit 58 adsorbs the sheet to the conveyance belt 56. By the suction, the position of the paper and the distance between each nozzle and the paper are fixed. During printing, the engine control unit 4 operates the suction unit 58.

  The image forming unit 5c records an image by ejecting ink onto the transport sheet. In other words, the image forming unit 5c performs printing. Image data for printing is supplied from the image processing circuit 12. As shown in FIGS. 1 and 2, the image forming apparatus 100 includes four line heads 50 (50Bk, 50C, 50M, and 50Y). Each line head 50 is provided above the conveyor belt 56. A fixed gap is provided between each line head 50 and the conveyor belt 56. Each line head 50 is fixed. Each line head 50 includes a plurality of nozzles. The opening of each nozzle faces the conveyor belt 56. Ink is ejected from each nozzle. The line head 50Bk ejects black ink. The line head 50C discharges cyan ink. The line head 50M ejects magenta ink. The line head 50Y discharges yellow ink. The ink lands on the transport paper. Thereby, an image is recorded (formed). An ink tank that supplies ink is provided for each line head 50.

  The control unit 1 is connected to the communication unit 6. The communication unit 6 includes communication hardware (connector, communication circuit) and software. The communication unit 6 communicates with the computer 200. The computer 200 is, for example, a PC or a server. The control unit 1 receives print data from the computer 200. The print data includes print settings and print contents. The print data includes data described in a page description language. The control unit 1 (image processing circuit 12) analyzes the received (input) print data. Based on the received printing data, the control unit 1 generates image data (raster data) used for image formation in the image forming unit 5c.

(Engine control unit 4)
Next, an example of the engine control unit 4 according to the embodiment will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of the engine control unit 4 according to the embodiment.

  The engine control unit 4 controls the printing unit 5. The engine control unit 4 is a substrate, for example. The engine control unit 4 includes a first control circuit 40, a timer 41, an engine ROM 42, and an engine RAM 43 (corresponding to a first storage unit). The first control circuit 40 includes a timer 41 and an engine I / F circuit 44. The engine I / F circuit 44 may be separate from the first control circuit 40.

  The first control circuit 40 is an integrated circuit such as a CPU (engine CPU). As the timer 41, a timer circuit provided in the CPU can be used. The timer 41 may be separate from the first control circuit 40. For example, the timer 41 may be a counter circuit that counts clocks externally attached to the engine CPU. The first control circuit 40 controls the operation of the printing unit 5 (print engine). The first control circuit 40 reads the first control software 45, the second control software 46, and the third control software 47 from the engine ROM 42 or the storage unit 2. Each read control software is stored in the engine RAM 43. Using the first control software 45, the second control software 46, and the third control software 47, the first control circuit 40 controls the printing operation.

  The first control software 45 is software for controlling the operation of the printing unit 5 (the paper feeding unit 5a, the paper feeding device 7, the paper conveying unit 5b, and the image forming unit 5c). For example, the first control software 45 controls the start and stop of the operation of the control target included in each part. The first control software 45 controls the operation timing of each part used for printing. The third software is software that generates the change permission data 92. Details of the change permission data 92 will be described later.

  The second control software 46 controls the engine I / F circuit 44. The second control software 46 is software that controls communication with the sheet feeding device 7. The second control software 46 is software for controlling the physical layer (engine I / F circuit 44) in order to communicate with the sheet feeding device 7. Hierarchically, the first control software 45 and the third control software 47 are superior to the third control software 47. A request (data) created by the first control software 45 is given to the second control software 46. The engine control unit 4 transmits data from the engine I / F circuit 44 using the third control software 47.

  The timer 41 measures time. The timer 41 measures the monitoring cycle T0. The monitoring period T0 is predetermined. The monitoring period T0 is 1 to several milliseconds (for example, 2 ms). The monitoring period T0 may be the shortest time among the periods that the timer 41 can count. Every time the timer 41 measures the monitoring period T0, the timer 41 temporarily changes the output level. The output of the timer 41 is input to the first control circuit 40. The timer 41 inputs a cycle elapse signal notifying that the monitoring cycle T0 has elapsed to the first control circuit 40. The first control circuit 40 recognizes that the current monitoring cycle T0 has ended and the next monitoring cycle T0 has started based on the cycle elapsed signal.

  The engine I / F circuit 44 is connected to the paper feeding unit 5 a, the paper transport unit 5 b, the image forming unit 5 c, and the paper feeding device 7. The first control circuit 40 generates request data (signal) for controlling the operations of the paper feed unit 5 a, the paper transport unit 5 b, the image forming unit 5 c, and the paper feed device 7. The first control circuit 40 transmits the generated request data to the engine I / F circuit 44. Based on an instruction from the engine control unit 4 (first control circuit 40), the paper feed unit 5a, the paper transport unit 5b, the image forming unit 5c, and the paper feed device 7 operate.

(Paper Feeder 7)
Next, an example of the sheet feeding device 7 according to the embodiment will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of the sheet feeding device 7 according to the embodiment.

  The paper feed device 7 includes a paper feed controller 7a. The paper feed control unit 7a controls the paper feed device 7 (optional device). For example, the paper feed control unit 7a is a control board. The paper feed controller 7 a includes a second control circuit 70, a paper feed ROM 76, and a paper feed RAM 77. The second control circuit 70 includes a paper feed I / F circuit 78. The paper feed I / F circuit 78 may be separate from the second control circuit 70.

  The second control circuit 70 is an integrated circuit such as a CPU, for example. The second control circuit 70 controls the operation of the paper feeding device 7 (optional device). The second control circuit 70 reads software for controlling the paper feeding device 7 from the paper feeding ROM 76 or the storage unit 2. The read control software is stored in the paper feed RAM 77. Using the read control software, the second control circuit 70 controls the paper feeding operation during printing.

  The second control circuit 70 (paper feed I / F circuit 78) communicates with the first control circuit 40 (engine I / F circuit 44). Further, the second control circuit 70 (paper feed I / F circuit 78) is connected to a control target. The control target of the second control circuit 70 is a member provided in the paper feeding device 7. Control targets include a paper feed motor 79, a paper feed clutch 710, a transport motor 711, and a fan motor 712.

  The paper feed motor 79 is a motor that rotates the optional paper feed roller 72. A plurality of paper feed motors 79 are provided. One paper feed motor 79 is provided for one optional paper feed roller 72 (paper cassette 71). Based on the control data received from the first control circuit 40, the second control circuit 70 rotates the paper feed motor 79 corresponding to the paper cassette 71 selected as the paper feed source. As shown in FIG. 2, a pair of rolling rollers 7 b is provided downstream of the optional paper feed roller 72. One roller pair 7b is provided for one optional paper feed roller 72. Each roller pair 7b eliminates the double feeding of paper. The upper roller of the pair of winding rollers 7b rotates in a direction to feed the paper downstream. The lower roller of the pair of separating rollers 7b rotates in a direction to return the paper to the paper cassette 71. The paper feed motor 79 also rotates the roller pair 7b. One paper feed motor 79 rotates the corresponding optional paper feed roller 72 and a pair of separating rollers 7b adjacent thereto.

  The paper feed clutch 710 is for temporarily stopping the rotation of the optional paper feed roller 72. The paper feed clutch 710 is an electromagnetic clutch. Depending on the level of the input voltage (current), connection and release can be switched. One paper feed clutch 710 is provided for one optional paper feed roller 72. When continuously supplying a plurality of sheets, the second control circuit 70 temporarily stops the optional sheet feeding roller 72 that is feeding based on the control data received from the first control circuit 40 (feeding). The paper clutch 710 is released and the corresponding paper feed motor 79 is kept rotating). When the previous sheet passes through the sheet cassette 71, the optional sheet feeding roller 72 is temporarily stopped. After forming a predetermined sheet interval, the first control circuit 40 restarts the rotation of the optional sheet feeding roller 72 (connection of the sheet feeding clutch 710).

  The transport motor 711 is a motor for rotating the optional transport roller pair 75. A plurality of optional conveyance roller pairs 75 are provided along the optional conveyance path 74. Therefore, a plurality of transport motors 711 may be provided. When the paper is fed from the paper feeding device 7, the second control circuit 70 rotates each transport motor 711 based on the control data received from the first control circuit 40. Thereby, each option conveyance roller pair 75 rotates. The sheet is sent toward the image forming unit 5c.

  The fan motor 712 rotates a fan provided in the sheet feeding device 7. The fan is provided, for example, for adjusting the temperature and temperature in the sheet feeding device 7. A plurality of fans and fan motors 712 may be provided. For example, when paper is fed from the paper feeding device 7, the second control circuit 70 rotates each fan motor 712 based on the control data received from the first control circuit 40. Thereby, each fan rotates.

  As described above, the sheet feeding device 7 includes a plurality of control objects. The engine control unit 4 (first control circuit 40) transmits control data (request) to the second control circuit 70. The control data is data (signal) for controlling the operation of the controlled object. The second control circuit 70 of the paper feeding device 7 is connected to be communicable with each control target. The second control circuit 70 controls the operation of each control target based on the control data (request) from the first control circuit 40. It can be said that the first control circuit 40 controls the second control circuit 70 and its controlled object.

  There are a plurality of types of control data that the first control circuit 40 transmits to the second control circuit 70. The control data is classified into first control data 9a, second control data 9b, and third control data 9c. The first control data 9a is control data for controlling the first target. The second control data 9b is control data for controlling the second target. The third control data 9c is control data for controlling the third target. Which of the members included in the sheet feeding device 7 is the first target, which is the second target, and which is the third target is predetermined. For example, among the control targets, the fan motor 712 is the first target. Among the control targets, the paper feed motor 79, the paper feed clutch 710, and the transport motor 711 are the second targets. Of the paper feed motor 79, the paper feed clutch 710, and the transport motor 711, the one to be controlled at a particularly high speed (to switch ON / OFF at a high speed) is the third target.

  That is, the first control circuit 40 transmits data for controlling the first target, the second target, and the third target to the second control circuit 70. The second control circuit 70 is connected to the first object, the second object, and the third object. Based on the control data received from the first control circuit 40, the second control circuit 70 controls the operations of the first object, the second object, and the third object. For example, the second control circuit 70 controls ON / OFF of the first target, the second target, and the third target.

(Transmission of the first control data 9a)
Next, an example of transmission of the first control data 9a according to the embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of transmission of the first control data 9a according to the embodiment.

  The first control circuit 40 generates first request data 81 based on the first control software 45. The first request data 81 is data for controlling the first target. In other words, the first control circuit 40 issues a data transmission request for controlling the first target. In FIG. 5, a time point t1 is a time point when the first request data 81 is generated (a transmission request is issued). The first control circuit 40 transmits the first request data 81 as the first control data 9a.

  The transmission of the first control data 9a is performed by the first communication method. The first communication method is communication using a mailbox. The first control circuit 40 transmits the first control data 9a to the second control circuit 70 using a mailbox. The mailbox function is a function for performing synchronous communication by passing a message placed in a memory. For example, the mailbox communication function is implemented in software (OS) such as Itron. When transmitting data using a mailbox, the first control circuit 40 creates a mailbox. For example, the first control circuit 40 allocates a partial area of the engine RAM 43 to a mailbox.

  When the first request data 81 is generated, the first control circuit 40 writes the first request data 81 in the message storage area of the engine RAM 43. Further, the first control circuit 40 writes the storage address (pointer) of the first request data 81 in the mailbox. Thereafter, based on the second control software 46, the first control circuit 40 transmits the first control data 9a. That is, the upper layer software requests the lower layer software to transmit data.

  For example, the second control circuit 70 confirms the address of the mailbox at the timing of receiving data. When the confirmation is made, the first control circuit 40 transmits the first request data 81 as the first control data 9a to the second control circuit 70 (paper feed I / F circuit 78). The transmission / reception using the mailbox has an advantage that the load on the first control circuit 40 can be relatively suppressed.

  However, in communication using a mailbox, a certain procedure is taken (writing to a mailbox, waiting for reception, etc.). Therefore, for the first control data 9a, the time interval from the generation of the first request data 81 until the second control circuit 70 actually receives the first control data 9a may be long. In FIG. 5, an example (first time interval T1) of the time interval in the first communication method is indicated by a solid arrow.

  A printer performs printing at high speed. Some controlled objects have problems in printing when the time interval from the request to the completion of communication becomes long. Therefore, the first target is not subject to a slight delay in control data among the control targets. For example, each fan motor 712 is a first target. The control data of each fan motor 712 is the first control data 9a. In addition, a notification that informs the second control circuit 70 (paper feed control unit 7a) of the state of the engine control unit 4 may be the first control data 9a. On the other hand, the first control circuit 40 transmits, using the second communication method or the third communication method, control data to be controlled that may cause a problem in printing when the time interval becomes longer.

(Generation and transmission of second control data 9b)
Next, an example of transmission of the second control data 9b according to the embodiment will be described with reference to FIGS. FIG. 6 is a diagram illustrating an example of transmission of the second control data 9b according to the embodiment. 7 and 8 are diagrams illustrating an example of generation of the second control data 9b according to the embodiment.

  A printer performs printing at high speed. Some control objects have problems in printing when the time interval from the request to the completion of transmission becomes long. Therefore, the second target is a control target in which delay in transmission of control data may be a printing problem. For example, the paper feed motor 79, the paper feed clutch 710, and the transport motor 711 are the second target. The control data of the paper feed motor 79, the paper feed clutch 710, and the transport motor 711 is the second control data 9b.

  The first control circuit 40 transmits the second control data 9b to the second control circuit 70 by the second communication method. The second control data 9b is data for controlling the second target. The transmission of the second control data 9b is performed based on the monitoring cycle T0. The timer 41 measures the monitoring cycle T0. The monitoring period T0 is set to be shorter than the reference interval. The reference interval is the time from the generation of the first request data 81 until the transmission of the first control data 9a to the second control circuit 70 is completed (until the second control circuit 70 actually receives the first control data 9a). This is the target time (empirical average time) of the target interval. For example, the reference interval can be determined by experiment. The time from the generation of the first request data 81 to the completion of transmission is measured a plurality of times. The average value of the measured time can be used as the reference interval.

  The first control circuit 40 generates the second request data 82 based on the first control software 45. In other words, the first control circuit 40 issues a data transmission request for controlling the second target. In FIG. 6, time points t <b> 2 and t <b> 3 are times when the second request data 82 is generated. The first control circuit 40 stores the generated second request data 82 in the register 48 (corresponding to the second storage unit). The register 48 is provided in the first control circuit 40. Since the register 48 is used, reading and writing can be performed at high speed.

  When the monitoring cycle T0 newly starts, the second control circuit 70 generates the second control data 9b based on the second request data 82 stored in the second storage unit during the previous monitoring cycle T0. Judge whether to do. When it is determined that the second control data 9b is to be generated, the first control circuit 40 generates the second control data 9b. After the generation, the first control circuit 40 transmits the second control data 9b to the second control circuit 70.

  Here, there are a plurality of second objects. The first control circuit 40 generates second request data 82 for controlling each second target. The second request data 82 is a bit string. In the bit string, bits representing ON / OFF requests of the second target operations as 1 and 0 are arranged. FIG. 7 shows an example of the second request data 82.

  The second request data 82 in FIG. 7 is 16-bit (2 bytes) data. The number of bits of the second request data 82 is equal to or greater than the number of the second object. According to the second request data 82 shown in FIG. 7, it is possible to control ON / OFF of the 16 second objects (motors and clutches). It is determined in advance which bit is the bit that controls which second object. In other words, a second target corresponding to each bit is determined in advance. In the second request data 82 of FIG. 7, “1” indicates ON and “0” indicates OFF. When the second object is a motor, bit “1” indicates rotation and “0” indicates stop. When the second object is a clutch, bit “1” indicates connection and “0” indicates release.

  As shown in FIG. 7, the second control circuit 70 also stores the result data 91 in the register 48. The performance data 91 is the second control data 9b transmitted last time. The actual data 91 (second control data 9b) and the second request data 82 have the same number of bits.

  Further, the first control circuit 40 generates change permission data 92 based on the third control software 47. The third control software 47 adjusts the ON / OFF timing of the motor and the clutch. For example, the change permission data 92 is generated so that the motors that should be turned off simultaneously are turned off at the same time. When each motor is turned on or off in turn, the first control circuit 40 changes the bits of the change permission data 92 by one bit or several bits at predetermined intervals based on the third control software 47. .

  The change permission data 92 has the same number of bits as the second request data 82 and the performance data 91. The second control circuit 70 sets the bit corresponding to the second target permitting the operation change at the current time as the permission value. The second control circuit 70 sets a bit corresponding to the second target that is not permitted to change the operation at the present time as a disallowed value. The relationship between the bit position and the second object is the same as that of the second request data 82. When the first bit of the second request data 82 corresponds to the motor A, the first bit of the change permission data 92 indicates whether the operation change of the motor A is permitted or not permitted. FIG. 7 shows an example of the change permission data 92. In the change permission data 92 of FIG. 7, “1” indicates a permission value (change permission), and “0” indicates a non-permission value (change not allowed).

  When the second request data 82 is generated during the immediately preceding monitoring cycle T0, the first control circuit 40 determines the second control data 9b based on the second request data 82, the actual data 91, and the change permission data 92. It is determined whether generation and transmission are necessary. When determined to be necessary, the first control circuit 40 generates the second control data 9b based on the second request data 82, the performance data 91, and the change permission data 92.

  Next, the flow of processing when the monitoring period T0 newly starts will be described with reference to FIG. For example, the start of FIG. 8 is a time when the first control circuit 40 recognizes the start of a new monitoring cycle T0 based on the output of the timer 41. First, the first control circuit 40 checks whether or not new second request data 82 is stored in the register 48 during the immediately preceding monitoring period T0 (step # 1). If not (No in Step # 1), the first control circuit 40 determines not to transmit the second control data 9b (Step # 2). Then, this flow ends (END).

  When the new second request data 82 is stored in the register 48 (Yes in Step # 1), the first control circuit 40 checks whether or not the change permission data 92 includes a permission value (Step S1). # 3). In other words, the first control circuit 40 checks whether or not all the change permission data 92 are non-permitted values. If the permission value is not included (No in step # 3), the flow proceeds to step # 2.

  When the permission value is included (Yes in Step # 3), the first control circuit 40 checks whether or not there is a difference between the second request data 82 and the actual data 91 (Step # 4). If there is no difference (No in Step # 4), the first control circuit 40 performs Step # 2. Then, this flow ends (END).

  If there is a difference (Yes in step # 4), the first control circuit 40 checks whether or not the second request data 82 and the actual data 91 are different at the bit position of the permission value in the change permission data 92. (Step # 5). If there is no difference between the data at the bit position of the permission value (No in step # 5), the first control circuit 40 performs step # 2. Then, this flow ends (END). Even if the second request data 82 and the record data 91 are different, if the change is not permitted, the first control circuit 40 does not generate or transmit the second control data 9b.

  If there is a difference between the data at the bit position of the permission value (Yes in step # 5), the first control circuit 40 newly generates the second control data 9b (step # 6). Then, the first control circuit 40 transmits the generated second control data 9b to the second control circuit 70 (step # 7). Next, the first control circuit 40 updates the record data 91 (step # 8). Then, this flow ends.

  In the example of FIG. 7, there is a difference between the first request data 81 and the performance data 91. When generating the second control data 9b, the first control circuit 40 uses the record data 91 for the bits of the non-permitted value in the change permission data 92. The first control circuit 40 copies the record data 91 for the black and white character bits in FIG. 7 and the bits surrounded by the broken lines (1-7th, 9-14th, 16th bits). Second control data 9b is generated.

  On the other hand, the first control circuit 40 uses the second request data 82 for bits that have different values in the second request data 82 and the actual data 91 and that are permitted values in the change permission data 92. In FIG. 7, the bit value of the second request data 82 is used for the bits (eighth and fifteenth) surrounded by a solid frame.

  As described above, when there is a difference between the request data and the actual data 91, the first control circuit 40 applies the value of the bit of the request data to the position of the bit of the permission value in the change permission data 92. Second control data 9b to which the bit value of the record data 91 is applied is generated at the bit position of the non-permitted value. The first control circuit 40 transmits the second control data 9b to the second control circuit 70 with the end of the monitoring cycle T0 (the start of a new monitoring cycle T0) as a trigger. Second control data 9b is generated based on the monitoring period T0. In FIG. 6, the boundary of the monitoring period T0 is indicated by a broken line. The time interval from the request to the completion of transmission of control data is less than the monitoring time. The time interval does not become longer than a certain length. In communication using a mailbox, the time interval is longer than the monitoring time (often). In FIG. 6, an example of the first time interval T1 is indicated by a solid line arrow. The second control data 9b can be transmitted faster than using a mailbox. After the request is generated, the state of the second target can be changed promptly. According to the second communication method, there is no significant delay in the operation (reaction) of the second object.

(Transmission of third control data 9c)
Next, an example of transmission of the third control data 9c according to the embodiment will be described using FIG. 9 and FIG. 9 and 10 are diagrams illustrating an example of transmission of the third control data 9c according to the embodiment.

  As described above, among the paper feed motor 79, the paper feed clutch 710, and the transport motor 711, the one to be controlled at a particularly high speed (to switch ON / OFF at a high speed) is the third target. The first control circuit 40 generates third request data for controlling the third target using control software. The first control circuit 40 transmits the third control data 9c for controlling the third target by the third communication method. The first control circuit 40 transmits the third request data as the third control data 9c.

  When the third control data 9c is generated, the first control circuit 40 immediately transmits the third control data 9c to the second control circuit 70. The second control circuit 70 controls the third target based on the received third control data 9c. In FIG. 9, t4 and t5 are times when the third request data is generated. In FIG. 10, t6 is the time when the third request data is generated. As shown in FIGS. 9 and 10, when the third request data is generated, the first control circuit 40 transmits the third control data 9c directly (simultaneously). In such direct transmission, the processing load of the first control circuit 40 may be larger than in the first communication method and the second communication method. However, direct transmission is performed only for some control objects (third objects). The processing load of the first control circuit 40 does not become too large.

  Furthermore, the first control circuit 40 sends the second control data 9b based on the second request data 82 newly stored in the register 48 during the current monitoring period T0 to the second control circuit 70 together with the third control data 9c. You may send it. In FIG. 10, a time point t7 is a time point when the second request data 9b is newly generated. In FIG. 10, the third request data is generated during the same monitoring period T0 as at the time point t7. In this case, when the third request data is generated, the first control circuit 40 determines whether or not the second request data 82 is newly generated during the current monitoring cycle T0 (whether or not it is stored in the register 48). Check.

  When the second request data 82 is newly generated during the current monitoring period T0, the first control circuit 40 executes the flowchart of FIG. In this case, step # 1 is skipped in the flowchart of FIG. When it is determined that the second control data 9b is not transmitted, the first control circuit 40 transmits only the third control data 9c. When the second control data 9b is newly generated, the first control circuit 40 transmits the newly generated second control data 9b after the third control data 9c. When the next monitoring cycle T0 is reached, the first control circuit 40 does not execute the flowchart of FIG. 8 for the second request data 82 determined in the previous monitoring cycle T0.

  As described above, the image forming apparatus 100 according to the embodiment includes the timer 41, the first control circuit 40, the second control circuit 70, the first storage unit (engine RAM 43), and the second storage unit (register 48). . The timer 41 measures a predetermined monitoring period T0. The second control circuit 70 communicates with the first control circuit 40. The second control circuit 70 is connected to the first target and the second target. The second control circuit 70 controls the operations of the first target and the second target. The first storage unit stores first request data 81 for controlling the first object. The second storage unit stores second request data 82 for controlling the second target. The first control circuit 40 generates first request data 81 based on the control software. The first control circuit 40 transmits the first request data 81 to the second control circuit 70 as the first control data 9a using a mail box. The second control circuit 70 controls the first target based on the received first control data 9a. Further, the first control circuit 40 generates second request data 82 for controlling the second object based on the control software. The first control circuit 40 stores the generated second request data 82 in the second storage unit. When the monitoring cycle T0 newly starts, the first control circuit 40 generates the second control data 9b based on the second request data 82 stored in the second storage unit during the previous monitoring cycle T0. . The first control circuit 40 transmits the generated second control data 9b to the second control circuit 70. The second control circuit 70 controls the second target based on the received second control data 9b. The monitoring period T0 is set to be shorter than the reference interval. The reference interval is from the generation of the first request data 81 until the transmission of the first control data 9a to the second control circuit 70 is actually completed (until the second control circuit 70 actually receives the first control data 9a). ()) This is the approximate time interval.

  According to this configuration, the first control data 9a (data for controlling the first target) can be transmitted and received between the control circuits using the mailbox. In addition, the second control data 9b can be transmitted and received between the control circuits based on the monitoring cycle T0. For a specific control target (second target), the time interval from the generation of request data to the completion of transmission can be set to a monitoring period T0 or less. The transmission delay of the second control data 9b can be made constant or less. That is, the second control data 9b can be transmitted and received at high speed. The second object can be controlled at high speed so as not to affect printing. The transmission method can be switched according to the control target and the data to be transmitted. Data can be transmitted by an appropriate transmission method in accordance with the control target and data to be transmitted. Further, since the communication based on the mailbox and the communication based on the monitoring cycle T0 are used together, the processing load on the control circuit does not become excessive.

  The second control circuit 70 is connected to the third target. The second control circuit 70 controls the operation of the third target. The first control circuit 40 generates third request data for controlling the third target using control software. When the third request data is generated, the first control circuit 40 immediately transmits the third request data to the second control circuit 70 as the third control data 9c. The second control circuit 70 controls the third target based on the received third control data 9c. Data (third control data 9c) for controlling the third target can be transmitted at high speed. The time interval from the transmission request for the third control data to the completion of the transmission can be made shorter than when the second control data 9b is transmitted. Data to be transmitted immediately can be immediately transmitted to the second control circuit 70. The third object can be controlled at high speed. The transmission method can be switched according to the control target and the data to be transmitted.

  The first control circuit 40 supplies the second control data 9b based on the second request data 82 newly stored in the second storage unit during the current monitoring cycle T0 to the second control circuit 70 together with the third control data 9c. Send. The second control data 9b can be transmitted to the second control circuit 70 simultaneously with the third control data 9c. The operations of the second object and the third object can be quickly controlled so that no problem occurs in the job.

  There can be a plurality of second objects. The first control circuit 40 generates, as the second request data 82, a bit string in which bits representing the ON / OFF requests for the operations of the second objects are arranged as 1 and 0. In the bit string, what number bit corresponds to which second object is predetermined. Further, the first control circuit 40 stores the second control data 9b transmitted last time in the second storage unit as the actual data 91. Based on the control software, the first control circuit 40 has the same number of bits as the actual data 91, uses the bit corresponding to the second target permitting the operation change at the current time as the permitted value, and does not permit the operation change at the current time. The change permission data 92 is generated in which the bits corresponding to the two objects are not permitted. When the second control data 9b is to be generated, the first control circuit 40 checks whether the change permission data 92 includes a permission value bit. When the change permission data 92 includes a permission value bit, the first control circuit 40 checks whether there is a difference between the second request data 82 and the actual data 91. When there is a difference between the second request data 82 and the actual data 91, the first control circuit 40 applies the bit value of the second request data 82 to the bit position of the permission value in the change permission data 92, and changes permission data. In 92, second control data 9b is generated by applying the bit value of the record data 91 to the bit position of the disallowed value. Data for controlling the operation of the second target can be collectively transmitted with a small number of bits. In addition, it is possible to switch only the operation of the second target for which the control software determines that the operation may be changed (the request may be reflected). Using the change permission data 92, it is possible to easily adjust the switching timing of the operation of each second target.

  When the second control data 9b is to be generated, when the change permission data 92 does not have a permission value bit or when there is no difference between the second request data 82 and the actual data 91, the first control circuit 40 2 The control data 9b is not generated and the second control data 9b is not newly transmitted. When there is no second object whose operation is to be changed, transmission of the second control data 9b can be skipped. The second control data 9b is not necessarily transmitted every monitoring period T0. The second control data 9b can be transmitted to the second control circuit 70 only when necessary. The processing load on the first control circuit 40 and the second control circuit 70 can be reduced.

  The image forming apparatus 100 includes a printing unit 5 that performs printing on the main body portion 101. An optional device is attached to the main body portion 101. The first control circuit 40 is provided in the main body portion 101. The second control circuit 70 is provided in the optional device (paper feeding device 7). The first object and the second object are included in the optional device. The first control circuit 40 provided in the main body device can give an operation instruction to the second control circuit 70 provided in the option device. The first control circuit 40 can control the operation of the optional device.

  The second target is any one of a motor (paper feed motor 79, transport motor 711) for rotating a rotating body for feeding paper and a clutch (paper feeding clutch 710) for controlling rotation and stop of the rotating body for feeding paper. Either or both. The second request data 82 and the second control data 9b are data for controlling either one or both of the motor and the clutch. Data for controlling the motor and the clutch can be promptly transmitted to the second control circuit 70. It is possible to prevent the displacement of the printing paper position from becoming large. The motor and clutch can be operated quickly. The motor and clutch can be stopped quickly.

  Although the embodiment of the present invention has been described, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

  The present invention is applicable to an image forming apparatus including a plurality of control circuits.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 101 Main part 40 First control circuit 41 Timer 43 Engine RAM (first storage unit) 45 First control software 46 Second control software 47 Third control software 48 Register (second storage unit) 5 Printing unit 7 Paper feeding device (optional device) 70 Second control circuit 79 Paper feeding motor (second and third target) 711 Transport motor (second and third target)
710 Feed clutch (second and third target) 712 Fan motor (first target)
91 Actual data 92 Change permission data 9b Second control data 9a First control data 9c Third control data T0 Monitoring cycle

Claims (7)

A timer for measuring a predetermined monitoring period;
A first control circuit;
A second control circuit that communicates with the first control circuit, is connected to a first object and a second object, and controls operations of the first object and the second object;
A first storage unit that stores first request data for controlling the first target;
A second storage unit that stores second request data for controlling the second target,
The first control circuit includes:
Generating the first request data based on control software;
Using a mailbox to send the first request data as first control data to the second control circuit;
The second control circuit controls the first object based on the received first control data,
The first control circuit includes:
Generating second request data for controlling the second object based on the control software;
Storing the generated second request data in the second storage unit;
When the monitoring cycle starts anew, generating second control data based on the second request data stored in the second storage unit during the previous monitoring cycle,
Transmitting the generated second control data to the second control circuit;
The second control circuit controls the second object based on the received second control data;
The monitoring period is set to be shorter than a reference interval,
The reference interval is an approximate time interval from the generation of the first request data to the actual transmission of the first control data to the second control circuit. . The second control circuit includes:
Connected to the third object,
Controlling the operation of the third object;
The first control circuit includes:
Using the control software to generate third request data for controlling the third object;
When generating the third request data, immediately send the third request data as third control data to the second control circuit,
The image forming apparatus according to claim 1, wherein the second control circuit controls the third object based on the received third control data. The first control circuit includes:
The second control data based on the second request data newly stored in the second storage unit during the current monitoring cycle is transmitted to the second control circuit together with the third control data. The image forming apparatus according to claim 2. A plurality of the second objects;
The first control circuit includes:
Generating a bit string in which bits representing 1 and 0 representing ON / OFF requests for the operation of each second target are arranged as the second request data;
In the bit string, what number bit corresponds to which second object is predetermined,
The first control circuit includes:
Storing the second control data transmitted last time in the second storage unit as performance data;
Based on the control software, the number of bits is the same as the actual data, the bit corresponding to the second object that permits the change of operation at the current time is set as a permission value, and the second object that does not permit the change of operation at the current time Generate change permission data with the corresponding bit as a disallowed value,
When trying to generate the second control data, check whether the change permission data has a bit of the permission value,
When there is a bit of the permission value in the change permission data, check whether there is a difference between the second request data and the performance data,
When there is a difference between the second request data and the actual data, the bit value of the second request data is applied to the bit position of the permission value in the change permission data, and the non-permission value in the change permission data. 4. The image forming apparatus according to claim 1, wherein the second control data to which the bit value of the record data is applied is generated at the position of the bit. The first control circuit includes:
When the second control data is to be generated, the second control data is generated when there is no bit of the permission value in the change permission data or when there is no difference between the second request data and the actual data. The image forming apparatus according to claim 4, wherein the second control data is not newly transmitted. The image forming apparatus
Including a printing section that prints on the main body,
An optional device is attached to the main body,
The first control circuit is provided in the main body portion,
The second control circuit is provided in the optional device,
The image forming apparatus according to claim 1, wherein the first object and the second object are included in the optional device. The second object is one or both of a motor for rotating a rotating body for feeding paper and a clutch for controlling rotation and stopping of the rotating body for feeding paper, or both,
The said 2nd request | requirement data and the said 2nd control data are data for controlling any one or both of the said motor and the said clutch, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. The image forming apparatus described.

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