JP2015166807A - image forming apparatus, control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus configured to properly determine the time when a state of a slave device has changed.SOLUTION: An image forming apparatus receives information from a slave unit including: detection means which detects that a state of the apparatus has changed; and transmission means which transmits information indicating the change of the state detected by the detection means. The image forming apparatus includes estimation means which estimates the time when the detection means detects the change of state, on the basis of the information received.

Description

  The present invention relates to an image forming apparatus, a control method, and a program.

  In the expansion tray used in the image forming apparatus, for the purpose of cost reduction, the image forming apparatus main body side communicates with the peripheral device side as a master and the peripheral side such as the expansion tray as a slave, and the master side instructs motor rotation and clutch on, On the other hand, in many cases, the slave side performs communication using a polling to respond the sensor state. This corresponds to the case where master-slave communication is performed using so-called serial communication.

  In Patent Document 1, if only periodic polling is used, an instruction to the extension tray and sensor status acquisition are delayed. Therefore, it is possible to reduce processing load due to polling or prevent delay due to communication processing. As an object, there has been disclosed an image forming apparatus that suppresses delay by changing or interrupting the polling order based on the position information of the paper, or by temporarily removing it from the polling target.

  In the technique described in Patent Document 1, in order to reduce the processing load of polling, an object is to reduce the processing load by removing it from the polling target. However, the technique described in Patent Document 1 narrows the polling cycle rather than removing it from the polling target in order to know the sensor change time of the additional tray as accurately as possible. Therefore, there is a problem that the effect of reducing the processing load cannot be obtained in the vicinity of the sensor change time or the time estimated to change.

  When performing polling communication, since communication is periodically performed from the master side to the slave side, a processing load associated with communication processing occurs. Although the processing load can be reduced by widening the polling cycle, on the other hand, the difference between the time when the expansion tray sensor changes state and the time when it is notified to the main unit (master) becomes large, so real-time control is possible. There is a problem of causing trouble.

  Specifically, if the function (control) described below is to be realized, the main body (master) needs to know the time of the state change of the additional tray sensor more accurately, which may cause trouble. is there.

<Case 1> Jam Detection Generally, whether a paper jam (jam) has occurred is determined by whether the leading edge of the sheet has reached the sensor position or the trailing edge of the sheet has passed by a specific time. There are many cases. In order to more accurately determine a paper jam (jam), it is necessary to more accurately grasp the sensor change time.

<Case 2> No registration roller In general, when performing final transfer onto a sheet, the sheet is often stopped just before the transfer position to adjust the transfer position (timing) with the image. The timing is adjusted by temporarily stopping the conveyance by hitting the sheet once against the registration roller and restarting the conveyance at a timing at which the arrival times of the sheet and the image coincide at the transfer position. Yes.

  However, in recent years, there is a configuration in which the registration roller is abolished for the purpose of reducing the cost and the transfer is performed without temporarily stopping. In this case, there is a problem that it is necessary to accurately grasp the position of the leading edge of the sheet and adjust the image writing timing so that the arrival time of the sheet and the image accurately matches at the transfer position. In order to determine the writing timing more accurately, it is necessary to grasp the sensor change time more accurately.

<Case 3> Paper Size Detection For example, in the image forming apparatus described in Patent Document 2 or Patent Document 3, the paper length is determined based on the on / off timing of the conveyance sensor. In addition, for example, there is a technique that warns that the print instruction and the paper size in the tray are different, and automatically reduces or enlarges the image size according to the device determination according to the paper size. In short, in order to determine the paper length more accurately, it is necessary to more accurately grasp the sensor change time.

<Case 4> Chattering removal Generally, when chattering removal is performed, there are many processes in which a sensor value is read every fixed period and it is determined that the sensor value is fixed when the sensor value is the same for a fixed number of times. In order to remove chattering more quickly and accurately, it is necessary to more accurately grasp the sensor change time.

  By the way, in order to reduce the cost of the extension tray itself and to ensure versatility and reusability of the control unit (CPU (Central Processing Unit) or control circuit) of the image forming apparatus, the extension tray performs only extremely simple processing. It is desirable that complicated control / determination is performed on the image forming apparatus main body side.

  That is, while the functions (control) from <Case 1> to <Case 4> described above are achieved, the processing load due to polling on the image forming apparatus main body side (master) is reduced, and the additional tray side (slave) is extremely simple. A state where only processing is performed is desirable.

  Summarizing the above points, it is desirable to achieve the following three matters. First, (1) reducing the number of polling operations and reducing the processing load on the main body side. Next, (2) the main body side grasps the change time of the sensor of the extension tray as accurately as possible, and enables the functions (control) of jam detection, registration rollerless, paper size detection, and chattering removal, or the accuracy is improved. To raise. (3) The processing on the extension tray side is as simple as possible.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an image forming apparatus capable of more accurately grasping the timing at which the state of the slave device has changed. To do.

  In order to solve the above-described problem, the image forming apparatus according to the first aspect of the present invention transmits a detection unit that detects a change in its own state and information indicating the change in its own state detected by the detection unit. An image forming apparatus that receives the information from a slave device including an estimation unit that estimates a time when the detection unit detects a state change based on the received information. .

  According to the present invention, it is possible to obtain an image forming apparatus capable of more accurately grasping the timing at which the state of the slave device has changed.

FIG. 2 is a schematic cross-sectional configuration diagram illustrating an internal structure when an extension tray is attached to the image forming apparatus according to the present embodiment. 1 is a schematic block diagram illustrating an internal configuration of an image forming apparatus according to an embodiment. It is a figure explaining the communication format between the image forming apparatus (main body) which concerns on this embodiment, and an expansion tray. FIG. 6 is a flowchart for explaining the operation of an extension tray mounted on the image forming apparatus according to the present embodiment. FIG. 6 is a flowchart illustrating an operation on the image forming apparatus main body side when chattering removal of an additional tray sensor mounted on the image forming apparatus according to the present embodiment is performed. FIG. 6 is a diagram illustrating a state of a 62-bit buffer in a chattering removal operation of an additional tray sensor mounted on the image forming apparatus according to the present embodiment. FIG. 10 is a flowchart for explaining an operation on the image forming apparatus main body side when a staying jam determination of an additional tray sensor mounted on the image forming apparatus according to the present embodiment is performed. FIG. 10 is a flowchart illustrating an operation on the image forming apparatus main body side when an image is transferred from an extension tray mounted on the image forming apparatus according to the present embodiment and transferred without being temporarily stopped by a registration roller. FIG. 6 is a flowchart illustrating an operation on the image forming apparatus side when paper size detection is performed in an additional tray sensor mounted on the image forming apparatus according to the present embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified thru | or abbreviate | omitted suitably. The present invention is characterized in that, in the communication processing between the image forming apparatus main body and the extension tray, information on the change in the state of the extension tray detected by the sensor is added to the communication data between the main body and the extension tray. It has become. The features of the present invention will be described in detail with reference to the following drawings.

  First, an internal structure when an extension tray is attached to the image forming apparatus according to the present embodiment will be described. FIG. 1 is a schematic cross-sectional configuration diagram illustrating an internal structure when an extension tray is attached to the image forming apparatus according to the present embodiment.

  As shown in FIG. 1, the image forming apparatus according to the present embodiment has a configuration in which AIO (All In One) cartridges (6Bk, 6M, 6C, 6Y) of each color are arranged along the transfer belt 5. Yes, so-called tandem type. The transfer belt 5 rotates counterclockwise in FIG. 1, and a plurality of AIO cartridges (electrophotographic process units) 6Bk, 6M, 6C, and 6Y are arranged in this order from the upstream side in the rotation direction.

  The plurality of AIO cartridges 6Bk, 6M, 6C, and 6Y have the same internal configuration except that the colors of the toner images to be formed are different. The AIO cartridge 6Bk forms a black image, the AIO cartridge 6M forms a magenta image, the AIO cartridge 6C forms a cyan image, and the AIO cartridge 6Y forms a yellow image. In the following description, the AIO cartridge 6Bk will be specifically described. The other AIO cartridges 6M, 6C, 6Y are the same as the AIO cartridge 6Bk. Therefore, for the components of the image forming units 6M, 6C, and 6Y, the symbols distinguished by M, C, and Y are displayed in the figure instead of Bk attached to the components of the image forming apparatus 6Bk. The description is omitted.

  The transfer belt 5 is an endless belt wound around a secondary transfer drive roller 7 and a transfer belt tension roller 8 that are rotationally driven. The secondary transfer drive roller 7 is driven to rotate by a drive motor (not shown), and the drive motor, the secondary transfer drive roller 7 and the transfer belt tension roller 8 serve as drive means for moving the transfer belt 5. Function.

  The image forming unit 6Bk includes a photoconductor 9Bk as a photoconductor, a charger 10Bk disposed around the photoconductor 9Bk, an exposure device 11, a developing device 12Bk, a cleaner blade 13Bk, and the like. The exposure unit 11 is configured to irradiate laser beams 14Bk, 14M, 14C, and 14Y that are exposure lights corresponding to image colors formed by the AIO cartridges 6Bk, 6M, 6C, and 6Y.

  At the time of image formation, the outer peripheral surface of the photoconductor 9Bk is uniformly charged by the charger 10Bk in the dark, and then exposed by the laser beam 14Bk corresponding to the black image from the exposure device 11 to form an electrostatic latent image. Is done. The developing device 12Bk visualizes the electrostatic latent image with black toner, thereby forming a black toner image on the photoreceptor 9Bk.

  This toner image is transferred onto the transfer belt 5 by the action of the primary transfer roller 15Bk at a position (primary transfer position) where the photoconductor 9Bk and the transfer belt 5 are in contact with each other. By this transfer, an image of black toner is formed on the transfer belt 5. After the transfer of the toner image, the photoreceptor 9Bk waits for the next image formation after the unnecessary toner remaining on the outer peripheral surface is wiped off by the cleaner blade 13Bk.

  As described above, the transfer belt 5 to which the black toner image is transferred by the AIO cartridge 6Bk is conveyed by the transfer belt 5 to the next AIO cartridge 6M. In the AIO cartridge 6M, a magenta toner image is formed on the photoreceptor 9M by a process similar to the image forming process in the AIO cartridge 6Bk. Then, the toner image is transferred while being superimposed on the black image formed on the transfer belt 5.

  The transfer belt 5 is further conveyed to the next AIO cartridges 6C and 6Y, and a cyan toner image formed on the photoconductor 9C and a yellow toner image formed on the photoconductor 9Y are subjected to the same operation. Then, the image is transferred onto the transfer belt 5 in a superimposed manner. Thus, a full-color image is formed on the transfer belt 5. The transfer belt 5 on which the full-color superimposed image is formed is conveyed to the position of the secondary transfer roller 16. In the image formation, in the case of printing only with black, the primary transfer roller 15M, the primary transfer roller 15C, and the primary transfer roller 15Y are retracted to positions separated from the photoreceptor 9M, the photoreceptor 9C, and the photoreceptor 9Y, respectively. Then, the above-described image forming process is performed only for black.

  In the case of printing in which paper is fed from the main body paper feed tray during the paper transport operation during image formation, the paper 4 stored in the main body paper feed tray 1 is rotated counterclockwise from the top to the paper feed roller 2. It is sent out in order by rotational driving, and waits at the registration roller 3 position. The driving of the registration roller 3 is started at a timing such that the toner image and the position of the paper 4 overlap on the toner image conveyed by the transfer belt 5 and the secondary transfer roller 16. At this time, the registration roller 3 feeds the paper 4 by being driven counterclockwise.

  In the case of printing in which paper is fed from the expansion tray 1A during the paper transport operation during image formation, the paper 4A stored in the expansion tray 1A rotates the paper feeding roller (extension tray) 2A counterclockwise from the top. Are sequentially sent out by being rotationally driven. Then, it waits at the registration roller 3 position. The subsequent processing is the same as in the case of printing in which paper is fed from the main body paper feed tray 1.

  The paper 4 sent out by the registration roller 3 transfers the toner image on the transfer belt 5 to the paper 4 by the secondary transfer roller 16, and then the toner image is fixed by heat and pressure by a fixing device. The paper is discharged to the outside of the image forming apparatus by a paper discharge roller 18 that is driven to rotate around. When performing double-sided printing, the paper discharge roller 18 is rotated counterclockwise before the paper 4 passes through the paper discharge roller 18, and the paper 4 is conveyed to the double-sided conveyance path. The sheet 4 conveyed to the duplex conveyance path is conveyed again to the registration roller 3 via the duplex roller 19.

  The paper 4 that has reached the registration roller 3 is again fed from the registration roller 3, and after the toner image is transferred to the opposite paper surface by the secondary transfer roller 16, the toner image is heated and pressured by the fixing device. It is fixed by. Then, the paper is discharged to the outside of the image forming apparatus by a paper discharge roller 18 that is driven to rotate clockwise.

  Next, the internal configuration of the image forming apparatus according to the present embodiment will be described. FIG. 2 is a schematic block diagram illustrating the internal configuration of the image forming apparatus according to the present embodiment.

  The CPU 25 is a CPU of the image forming apparatus (main body) 20 and comprehensively controls access to various devices connected to the system bus 38 based on a control program stored in a ROM (Read Only Memory) 26. In addition, it controls input / output of sensors connected via an I / O (Input / Output) 31 and electrical components such as a motor, a clutch, and a heater. That is, the ROM 26 stores a control program of the CPU 25 as shown in flowcharts of FIGS. 5, 7, 8, and 9 to be described later. The CPU 25 executes a control program stored in the ROM 26.

  A RAM (Random Access Memory) 27 is a RAM that functions as a main memory, a work area, and the like of the CPU 25, and is used as a recording data development area, an environment data storage area, and the like. An NVRAM (Non Volatile RAM) 30 stores information related to the image forming apparatus used by the control program. A printer mode or the like can be set by an operation panel 29 connected via an operation panel I / F (Interface) 28.

  A paper feed motor 35 is driven to feed paper from each paper feed tray, and a registration sensor 34 and a double-side sensor 36 are installed to detect paper jam (jam). An image processing IC (Integrated Circuit) 32 receives the image data from the controller 33 and transmits the image data to the exposure device 11 (FIG. 1). Further, the image processing IC 32 has a function of calculating the toner consumption amount per page from the image data received from the controller 33 and notifying the CPU 25 via the system bus 38 of the calculated toner consumption amount. The paper discharge direction switching solenoid 37 is for operating a switching plate that conveys paper to a selected paper discharge tray when there are a plurality of paper discharge trays.

  The CPU 25 can communicate with the extension tray 50 through a UART (Universal Asynchronous Receiver Transmitter) 24. A CPU (extension tray) 51 is a CPU of the expansion tray 50. A CPU (extension tray) 51 controls input / output of electrical components such as sensors and motors connected via the I / O 54.

  A CPU (extension tray) 51 can communicate with the image forming apparatus (main body) 20 through a UART (extension tray) 52. An oscillation circuit (not shown) is mounted inside the CPU (extension tray) 51, and can generate a clock with a cycle of 1 msec.

  Next, a communication format between the image forming apparatus (main body) and the extension tray according to the present embodiment will be described. FIG. 3 is a diagram illustrating a communication format between the image forming apparatus (main body) and the extension tray according to the present embodiment.

  As for the form of communication, 4-byte handshake communication is performed with the image forming apparatus (main body) 20 (hereinafter referred to as “main body side”) as a master and the extension tray 50 side as a slave. First, a communication format from the main body side 20 to the expansion tray 50 side will be described. As shown in the upper part of FIG. 3, the 31st bit means an on / off request of the paper feed motor (extension tray) 56, 0 means an off instruction, and 1 means an on instruction. The 30th to 0th bits are invalid and do not affect at all.

  Next, a communication format from the extension tray 50 side to the main body side will be described. As shown in the lower part of FIG. 3, the 31st bit is the state of the paper feed motor (extension tray) 56, 0 means an off state, and 1 means an on state. The initial value is 0. The 30th bit is the state of the extension tray sensor 55 at the moment when response data is transmitted from the extension tray 50 side to the main body side 20 at present. 1 means an on state and 0 means an off state.

  The 29th bit stores the state of the extension tray sensor 55 one clock before. As described with reference to FIG. 2 in the present embodiment, since 1 clock = 1 msec, the state of the additional tray sensor 55 before 1 msec is shown. Thereafter, the 28th bit continues for 2 clocks, the 27th bit continues for 3 clocks, and the 0th bit indicates a state before 30 clocks (30 msec). That is, it represents a change in the state of the additional tray sensor 55 detected in a predetermined cycle from the current time to a period that is a predetermined period back.

  Next, the operation of the extension tray attached to the image forming apparatus according to the present embodiment will be described. FIG. 4 is a flowchart for explaining the operation of the extension tray attached to the image forming apparatus according to the present embodiment.

  In FIG. 4, step 1 (S1) is a flow for initializing the response buffer. The response buffer is set to 4 bytes which is the same as the communication format, and the MSB (Most Significant Bit) is set to bit 31 and the LSB (Least Significant Bit) is set to bit 0 as in the communication format. In step 1 (S1), the response buffer is cleared to zero.

  Step 2 (S2) is a step of waiting for the passage of time. In this step, it waits for one clock to elapse. Step 3 (S3) is a step of shifting the response buffer to the right once. By this step 3 (S 3), the information of the extension tray sensor 55 one clock before stored in bit 30 is moved to bit 29. Similarly, the 29th bit and the 28th bit are followed, and the 0th bit information is discarded. It is assumed that the value added to bit 31 is “0”.

  Step 4 (S4) is a flow for substituting the information of the current extension tray sensor 55 into the response buffer. If the information of the current extension tray sensor 55 is on, 1 is substituted for bit 30 and if it is off, 0 is substituted. Step 5 (S5) is a flow for checking whether there is data received from the main body 20 or not. When there is received data (S5: YES), the process proceeds to step 6 (S6), and when there is no received data (S5: NO), the process returns to step 2 (S2).

  Step 6 (S6) is a flow for confirming received data from the main body side 20. It is determined whether or not the 31st bit indicating the on / off request of the paper feed motor (additional tray) 56 shown in the upper part of FIG. When the 31st bit is 1 (S6: YES), the process proceeds to Step 7 (S7), and when it is 0 (S6: NO), the process proceeds to Step 8 (S8).

  Step 7 (S7) is a step of turning on the paper feed motor (extension tray) 56. That is, as explained in the lower part of FIG. 3, the 31st bit means the state of the paper feed motor (extension tray) 56, 0 means off, and 1 means on state. Therefore, 1 is substituted into bit 31 of the response buffer in order to turn on the paper feed motor (extension tray) 56 in accordance with an instruction from the main body side 20.

  Step 8 (S8) is a step in which the paper feed motor (extension tray) 56 is turned off. That is, as explained in the lower part of FIG. 3, the 31st bit means the state of the paper feed motor (extension tray) 56, 0 means off, and 1 means on state. Therefore, 0 is substituted into the response buffer bit 31 in order to turn off the paper feed motor (extension tray) 56 in accordance with an instruction from the main body side 20.

  Step 9 (S9) is a step of transmitting response data to the main body side 20. The data itself in the response buffer is used as response data and transmitted to the main body 20. As described above, the processing on the side of the extension tray 50 is realized by only taking information on the change in the value of the extension tray sensor 55 and substituting the value into the response buffer. It is clear that

  Next, the operation on the image forming apparatus main body side when chattering that is mechanical vibration of the additional tray sensor mounted on the image forming apparatus according to the present embodiment is removed will be described. FIG. 5 is a flowchart for explaining the operation on the image forming apparatus main body side when the chattering removal of the additional tray sensor attached to the image forming apparatus according to the present embodiment is performed.

  Here, the specification of the extension tray sensor 55 assumes that the sensor value is fixed when the same value is detected five times in a cycle of 1 msec. Note that the flow shown in FIG. 5 is started from the system startup and is continuously operating.

  In FIG. 5, step 1 (S1) is a step of clearing a 62-bit buffer to zero. The reason for the 62-bit length is that the same value may be detected over two communication histories, and therefore it is necessary to buffer information on the change in the additional tray sensor 55 for two communications. The MSB of the 62-bit buffer is referred to as bit 61, and hereinafter referred to as bit 60, bit 59,..., Bit 0 toward the LSB side. FIG. 6 shows the names of bits in the 62-bit buffer and the meaning of each bit. FIG. 6 is a diagram showing the state of a 62-bit buffer in the chattering removal operation of the additional tray sensor mounted on the image forming apparatus according to the present embodiment.

  Step 2 (S2) is a step for performing polling communication with a cycle of 30 msec together with steps 3 to 6 (S3 to S6). According to the lower communication format in FIG. 3, the state of the additional tray sensor 55 30 clocks before, that is, the state of the additional tray sensor 55 up to 30 msec is recorded, and therefore, the polling interval is 30 msec. In step 2 (S2), the process waits for 30 msec and proceeds to step 3 (S3).

  Step 3 (S3) is a step of performing communication from the main body side 20 to the expansion tray 50 side. That is, communication is performed according to the upper communication format of FIG. At this time, it is assumed that the on / off request (the 31-bit value of the upper communication format in FIG. 3) of the paper feed motor (extension tray) 56 is not changed.

  Step 4 (S4) is a step of recording information on the value of the extension tray sensor 55 for the past 62 bits in a 62-bit buffer. After the 62-bit length buffer is shifted to the right by 31 bits, bit 0 is copied from bit 30 to bit 61 of bit 61 to bit 31 of the received data obtained in step 3 (S3). As a result, the buffer of 62 bits length is such that bit 61 is the current value of the additional tray sensor 55, bit 60 is the value of the additional tray sensor one clock before,..., Bit N (0 ≦ N ≦ 60) is 61-N clocks before. This means the value of the extension tray sensor 55 value. When this state is illustrated, a 62-bit buffer is in a state as shown in FIG.

  Step 5 (S5) is a step for confirming whether or not there is a portion where the same value is detected five times in the past from the data received in step 3 (S3). Specifically, it is sequentially confirmed whether bit 61 to bit 57, bit 60 to bit 56,..., Bit 4 to bit 0 of the received data have the same value. If the same value is detected five times in succession (S5: YES), the process proceeds to step 6 (S6). If not (S5: NO), the process returns to step 2 (S2).

  Step 6 (S6) is a step of determining the value detected in step 5 (S5) as the value of the extension tray sensor 55. Further, the time when the value of the extension tray sensor 55 is determined is obtained as follows. That is, when the location where the same value is detected five times in step 5 (S5) is from bitN to bitN-4 (4 ≦ N ≦ 61), the time when the sensor value is determined is (61−N ) Msec ago. In short, when the same value is continuously obtained for a predetermined period, the last time when the same value is obtained is determined as the time when the sensor value is determined.

  In this way, by estimating the time when the value of the extension tray sensor 55 is determined from the change history of the value of the extension tray sensor 55 in S5, the polling cycle (S2) can be set to a long cycle of 30 msec and 1 clock (1 msec). ) Unit accuracy can be obtained. As a result, even if the polling cycle is relaxed, it is possible to reduce the processing load on the main body side.

  Next, the operation on the image forming apparatus main body side in the case of performing the stay jam determination of the additional tray sensor mounted on the image forming apparatus according to the present embodiment will be described. FIG. 7 is a flowchart for explaining the operation on the image forming apparatus main body side in the case of performing the stay jam determination of the additional tray sensor mounted on the image forming apparatus according to the present embodiment. The flow shown in FIG. 7 is started after the main body side receives the print instruction and issues a rotation instruction to the paper feed motor (extension tray) 56 on the extension tray 50 side.

  First, the extension tray sensor retention jam is the trailing edge of the paper within the “paper length / linear velocity + margin” time after the leading edge of the paper as the recording medium supplied from the extension tray 50 passes the extension tray sensor 55. Means the case where it does not pass through the additional tray sensor 55. When it is determined that the extension tray sensor is jammed, all the motors on the main body side 20 and the extension tray 50 side are stopped. For ease of explanation, the paper length is 200 mm, the linear velocity is 100 mm / sec, and the margin is 50 msec.

  Step 1 (S1) is a step for waiting for a predetermined time. Together with step 2 (S2), periodic polling is realized. According to the lower format of FIG. 3 described above, the state of the extension tray sensor 55 is recorded 30 clocks before the extension tray 50, that is, before 30 msec.

  Step 2 (S2) is a step of performing communication from the main body side to the expansion tray 50 side. Communication is performed according to the upper format of FIG. At this time, it is assumed that the on / off request (the 31-bit value of the upper communication format in FIG. 3) of the paper feed motor (extension tray) 56 is not changed.

  Step 3 (S3) is a step of determining whether or not the state of the additional tray sensor 55 has changed. As described with reference to FIG. 5, it is determined whether or not the chattering of the extension tray sensor 55 is removed and the determined sensor value of the extension tray sensor 55 is “1”. If the determined value is “1” (S3: YES), it is considered that the sensor value is determined to be in the on state. Therefore, the time when the value of the additional tray sensor 55 in step 4 (S4) is determined to be in the on state is estimated. Proceed to If the sensor determination value is not “1” (S3: NO), the sensor value of the additional tray sensor 55 has not yet been determined, so the process returns to step 1 (S1) to continue the polling communication.

  Step 4 (S4) is a step of calculating the time when the sensor value of the additional tray sensor 55 is fixed. As described in step 6 (S6) in FIG. 5, the time when the sensor value of the additional tray sensor 55 is determined is estimated. Furthermore, at this step, counting of the jam detection timer used in step 7 (S7) is started. In this case, paper length / line speed + margin = 200 / (100/1000) + 50 = 2050 msec.

  Step 5 (S5) is a step of waiting for a certain period of time as in step 1 (S1). Periodic polling is realized in combination with step 6 (S6) to step 8 (S8). Step 6 (S6) is a step of performing communication from the main body side 20 to the expansion tray 50 side. Communication is performed according to the upper format of FIG. At this time, it is assumed that the on / off request (the 31-bit value of the upper communication format in FIG. 3) of the paper feed motor (extension tray) 56 is not changed.

  Step 7 (S7) checks whether the jam detection timer is up. The jam detection timer is a timer that starts counting when step 4 (S4) is executed. If the time is up (S7: YES), it is determined that a paper jam has occurred, and the process proceeds to step 11 (S11). If the time is not up (S7: NO), the process proceeds to step 8 (S8).

  Step 8 (S8) is a step of determining whether or not the state of the additional tray sensor 55 has changed. As described with reference to FIG. 5, it is determined whether or not the chattering of the extension tray sensor 55 is removed and the determined sensor value of the extension tray sensor 55 is “0”. If the confirmed value is “0” (S8: YES), it is considered that the sensor value is confirmed in the off state, and therefore the step of estimating the time when the value of the additional tray sensor 55 in step 9 (S9) is confirmed in the off state. Proceed to If the sensor fixed value is not “0” (S8: NO), the sensor value of the additional tray sensor 55 has not been fixed yet, so the process returns to step 5 (S5) to continue the polling communication.

  Step 9 (S9) is a step of calculating the time when the sensor value of the additional tray sensor 55 is determined. As described in step 6 (S6) in FIG. 5, the time when the sensor value of the additional tray sensor 55 is determined is estimated.

  In step 10 (S10), the difference between the time when the sensor value of the additional tray sensor 55 estimated in step 4 (S4) and step 9 (S9) is determined in the on state and the time determined in the off state is calculated. . Then, it is confirmed whether or not the sheet length / linear velocity + margin = 2050 msec or more in this case. If it is 2050 msec or longer (S10: YES), it is determined that a jam has occurred, and the process proceeds to step 11 (S11). When that is not right (S10: NO), this flow is complete | finished. Step 11 (S11) is a step in which the operation related to conveyance is stopped because it is determined that a paper jam (jam) has occurred.

  As described above, by estimating the time when the extension tray sensor 55 is turned on / off in S4 and S9, the polling cycle (S1, S5) can be set to a long cycle of 30 msec, and the accuracy in units of 1 clock (1 msec). Is obtained. As a result, even if the polling cycle is relaxed, it is possible to achieve both a reduction in processing load on the main body side and an improvement in the accuracy of jam detection.

  Next, the registration rollerless control operation of the image forming apparatus according to the present embodiment will be described. FIG. 8 is a flowchart for explaining the operation on the image forming apparatus main body side when paper is fed from an extension tray mounted on the image forming apparatus according to the present embodiment and an image is transferred without being temporarily stopped by a registration roller. . When this flow is performed, it is assumed that the registration roller 3 and the registration sensor described in FIG. 1 do not exist or do not function. In order to simplify the explanation, the following assumptions are made.

  Distance from exposure position of laser beam 14Bk to secondary transfer (electrostatic latent image and toner image movement distance = 500 mm, distance from paper feed roller (additional tray) to secondary transfer (paper moves along transport path) Distance) = 700 mm, linear velocity = 100 mm / sec, color mode is monochrome (only Bk color), and the flow shown in FIG. The operation is started after a rotation instruction is issued to the sheet feeding motor (additional tray) 56.

  Steps 1 (S1) to 4 (S4) are the same as Steps 1 (S1) to 4 (S4) described in FIG. Step 5 (S5) is a step of waiting for a predetermined time to elapse after the leading edge of the sheet passes through the additional tray sensor 55 until the start of exposure. Here, the distance from the paper feed roller (additional tray) to the secondary transfer (the distance that the paper moves along the conveyance path) −the distance from the exposure position of the laser beam 14Bk to the secondary transfer (the electrostatic latent image and the toner) Image moving distance) / linear velocity− (current time−sensor value change time) are obtained. That is, it waits until (700−500) / (100/1000) − (30−N) * 1 msec = 2000− (30−N) msec.

  Step 6 (S6) is a step of starting exposure. In step 5 (S5), since the timing is adjusted so that the paper and the toner image can be transferred at the secondary transfer position, exposure starts in this step after a predetermined time has elapsed.

  As described above, by estimating the time when the extension tray sensor 55 is turned on in S4, the accuracy of 1 clock (1 msec) unit can be obtained even if the polling cycle (S1) is set to a long cycle of 30 msec. As a result, even if the polling cycle is relaxed, it is possible to achieve both reduction in the processing load on the main body side and accurate exposure start timing.

  Next, the paper size detection operation of the image forming apparatus according to the present embodiment will be described. FIG. 9 is a flowchart for explaining the operation on the image forming apparatus side when paper size detection is performed in the additional tray sensor mounted on the image forming apparatus according to the present embodiment. The flow shown in FIG. 9 is started after the main body side receives the print instruction and issues a rotation instruction to the paper feed motor (extension tray) on the extension tray 50 side.

  Steps 1 to (S1) to 4 (S4) are the same as steps 1 (S1) to 4 (S4) described in FIG. Step 5 (S5) is a step of waiting for a predetermined time. Together with step 6 (S6), periodic polling is realized. Since step 6 (S6) is the same as step 2 (S2), description thereof is omitted.

  Step 7 (S7) is a step of determining whether or not the state of the additional tray sensor 55 has changed. As described with reference to FIG. 5, it is determined whether or not the chattering of the extension tray sensor 55 is removed and the determined sensor value of the extension tray sensor 55 is “0”. If the confirmed value is “0” (S7: YES), it is considered that the sensor value is confirmed in the off state, and therefore the step of estimating the time when the value of the additional tray sensor 55 in step 8 (S8) is confirmed in the off state. Proceed to If the sensor determined value is not “0” (S7: NO), the value of the additional tray sensor 55 has not been determined yet, so the process returns to step 5 (S5) to continue the polling communication.

  Step 8 (S8) is a step of calculating the time when the sensor value of the extension tray sensor 55 is fixed in the off state. As described in step 6 (S6) in FIG. 5, the time when the sensor value of the additional tray sensor 55 is determined is estimated.

  Step 9 (S9) is based on the required time from when the sensor value of the extension tray sensor 55 estimated in step 4 (S4) and step 8 (S8) is determined in the on state to when it is determined in the off state. In this step, the length of the passed paper is estimated. Specifically, it is estimated by an expression of “(addition tray sensor 55 off time−addition tray sensor 55 on time) * linear velocity”.

  In this way, by estimating the time when the extension tray sensor 55 is turned on / off in S4 and S8, the polling cycle (S1, S5) can be set to a long cycle of 30 msec, and the accuracy in units of 1 clock (1 msec). Is obtained. As a result, even if the polling period is relaxed, it is possible to achieve both a reduction in processing load on the main body side and paper size detection.

  The operations of the functional blocks constituting the image forming apparatus according to the present embodiment shown in FIGS. 5, 7, 8, and 9 can be executed by a program on a computer. That is, the CPU 25 of the image forming apparatus (main body) 20 loads a program stored in the ROM 26. This is realized by sequentially executing each processing step of the program.

  As described above, in the present invention, when the image forming apparatus is a master apparatus and the extension tray is a slave apparatus, information on a change in state of the slave apparatus is added to communication data exchanged between the two. As a result, the master device can accurately grasp the timing of the state change of the slave device. Further, since the master device recognizes the timing of the state change of the slave device, the processing load on the master device can be reduced by increasing the polling interval from the master device to the slave device and reducing the number of times. Furthermore, since the master device recognizes the timing of the status change of the slave device, the slave device only needs to store information on the status change of the slave device, thereby simplifying the processing of the slave device.

  As described above, according to the present invention, it is possible to obtain an image forming apparatus, a control method, and a program that can more accurately grasp the timing at which the state of the slave device has changed.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments thereof, various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the invention as defined in the claims. is there.

1 Main body feed tray 1A Expansion tray 2 Feed roller 2A Feed roller (extension tray)
3 Registration roller 4 Paper 4A Paper (extension tray)
5 Transfer Belt 6 AIO Cartridge 6Bk AIO Cartridge (K)
6M AIO cartridge (M)
6C AIO cartridge (C)
6Y AIO cartridge (Y)
7 Secondary transfer driving roller 8 Transfer belt tension roller 9 Photoreceptor 9Bk Photoreceptor (K)
9M photoconductor (M)
9C photoconductor (C)
9Y Photoconductor (Y)
10 Charger 10Bk Charger (K)
10M charger (M)
10C Charger (C)
10Y Charger (Y)
11 Exposure unit 12 Development unit 12Bk Development unit (K)
12M Developer (M)
12C Developer (C)
12Y Developer (Y)
13, 13Bk, 13M, 13C, 13Y Cleaner blade 14, 14Bk, 14M, 14C, 14Y Laser light 15Bk Primary transfer roller (Bk)
15M Temporary transfer roller (M)
15C Temporary transfer roller (C)
15Y Temporary transfer roller (Y)
16 Secondary transfer roller 17 TM sensor 18 Paper discharge roller 19 Double-sided roller 20 Image forming apparatus (main body)
24 UART
25 CPU
26 ROM
27 RAM
28 Operation panel I / F
29 Operation panel 30 NVLAM
31, 54 I / O
32 Image processing IC
33 Controller 34 Registration sensor 35 Lubrication motor 36 Double-sided sensor 37 Paper discharge method switching solenoid 38 System bus 50 Expansion tray 51 CPU (extension tray)
52 UART (extension tray)
53 System bus (extension tray)
55 Extension tray sensor 56 Paper feed motor (extension tray)

Japanese Patent No. 4644310 Japanese Patent No. 2941101 Japanese Patent Laid-Open No. 2002-086818

Claims (10)

An image forming apparatus that receives the information from a slave device that includes a detection unit that detects a change in the state of the device and a transmission unit that transmits information indicating the state change of the device detected by the detection unit.
An image forming apparatus comprising: an estimation unit configured to estimate a time when the detection unit detects a state change based on the received information.   When the value of the information to be received becomes the same value continuously for a predetermined period, the estimation means determines that the last time point when the value becomes the same value is the time when the detection means detects the state change. The image forming apparatus according to claim 1.   The state change of itself is a stop of the mechanical vibration generated in the slave device, and the estimation means indicates that the value of the information corresponding to the stop of the mechanical vibration becomes the same value continuously for a predetermined period. 3. The image forming apparatus according to claim 1, wherein the last time point when the same value is reached is determined as a time when the detection unit detects the stop of the mechanical vibration. 4.   The detection means detects the passage of the leading edge and the trailing edge of the recording medium supplied from the slave device, and the value of the information corresponding to the passage of the leading edge within a predetermined time corresponds to the passage of the trailing edge. 4. The image forming apparatus according to claim 1, further comprising means for determining that the recording medium is clogged when the information value does not change.   The image forming apparatus according to claim 4, wherein an image is transferred to the recording medium after a predetermined time has elapsed since the leading edge of the recording medium has passed.   6. The image forming apparatus according to claim 4, wherein the length of the recording medium is estimated based on a required time from the passage of the leading end of the recording medium to the passage of the trailing end.   The image according to any one of claims 1 to 6, wherein the information is information indicating a change in the state of the apparatus detected at a predetermined cycle from a current time to a period that is a predetermined period. Forming equipment.   The image forming apparatus according to claim 1, wherein polling communication is performed with respect to the slave device. A control method for an image forming apparatus that receives the information from a slave device, comprising: a detecting unit that detects a change in its own state; and a transmitting unit that transmits information indicating the change in its own state detected by the detecting unit. And
A control method comprising a step of estimating a time when the detection means detects a state change based on the received information. To a computer of an image forming apparatus that receives the information from a slave device, including a detection unit that detects a change in the state of the device and a transmission unit that transmits information indicating the change in the state of the device detected by the detection unit.
A program for realizing a process of estimating a time when the detection unit detects a state change based on the received information.

Images