JP2006178079A - Device for detecting connection of external equipment, and image forming apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for detecting the connection of external equipment realizing reduction in the number of terminals and the number of connectors, and an image forming apparatus, including the same. <P>SOLUTION: The connector 4 of an equipment body 1 and the connector 13 of external expansion equipment 10 can be connected to each other; a capacitor C is connected between an input/output terminal 3, connected to one terminal of the connector 4 of the equipment body 1 and ground; the capacitor C is charged under control by a control circuit 2; the charge of the capacitor C is discharged by a resistance R connected to one terminal of the connector 13 of the external extension equipment 10; and the potential of the input/output terminal 3 of the equipment body 1 is discriminated after predetermined time elapses, so that it is discriminated whether the external equipment have been connected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an external device connection detection device and an image forming apparatus including the external device connection detection device. For example, the present invention relates to an external device connection detection device that detects whether an optional device is externally connected to the image forming device and an image forming apparatus including the external device connection detection device.

  In the image forming apparatus, an optional device such as a finisher may be connected to the device body. In such a case, the device main unit detects whether the optional device is connected, and if it is detected that the device is connected, the device main unit supplies power to the optional device or the device main unit Various control signals are transmitted and received between the device side and the option device side.

In order to detect whether an optional device is connected to the device body, Japanese Patent Laid-Open No. 2002-264428 (Patent Document 1) connects the device body and the optional device with a connector having first and second terminals. When the device main body outputs a predetermined voltage to the first terminal of the connector and detects that the same voltage as the voltage output to the first terminal is output to the second terminal, the optional device is connected. An image forming apparatus that detects that the image is detected is described.
JP 2002-264428 A (paragraph numbers 0019 to 0024, FIG. 2)

  In Patent Document 1, in order to detect that an optional device is connected, at least two dedicated terminals must be provided on the connector. Moreover, in order to connect a plurality of optional devices, it is necessary to provide a plurality of connectors.

  For this reason, there exists a problem of causing the high cost by increasing the terminal of a connector or increasing the number of connectors.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an external device connection detection device that reduces the number of terminals and the number of connectors, and an image forming apparatus including the same.

The present invention is an external device connection detection device that detects whether or not an external device is connected to the device body, and is connected between a terminal to which the external device is connected and a terminal and a reference potential line. The charge storage means and the charge storage means are charged, the potential of the terminal is determined after a predetermined time has elapsed, and if it is the first potential, it is determined that an external device is not connected, and the charge storage means is discharged and the first And a control means for determining that the external device is connected if the second potential is different from the potential of the other aspect of the present invention, whether or not the external device is connected to the device body. An external device connection detection device to detect, wherein a terminal of the device main body and a terminal of the external device are connectable, and a resistor is connected between the terminal of the external device and the reference potential line. Between the terminal of the main unit and the reference potential line Charge storage means connected to the battery, charge the charge storage means, determine the terminal potential of the device body after a predetermined time, and if it is the first potential, determine that the external device is not connected, charge storage Control means for determining that an external device is connected if the means is discharged and the second potential is different from the first potential.

  Preferably, the predetermined time is a time determined by a time constant between the resistance of the external device and the charge storage means.

  Preferably, a plurality of external devices are prepared, and the resistors connected between the respective terminals and the reference potential line are selected to have different resistance values, and the control means charges the charge storage means. Then, after the time determined by the time constant between the resistance of the connected external device and the charge storage means has elapsed, the terminal potential of the device body is determined to determine which external device is connected.

  Preferably, the control means transmits / receives an operation signal to / from the external device via the terminal of the device main body and the terminal of the external device after completing the determination of the connection of the external device.

  Another aspect of the present invention is an image forming apparatus including the external device connection detection device described above.

  The present invention charges the charge storage means connected between the terminal of the device body and the reference potential line, and is connected between the terminal of the external device connected to the terminal of the device body and the reference potential line. It is possible to determine whether or not an external device is connected by discharging the charge of the charge accumulating means with a resistor and determining the potential of the terminal of the device body after a predetermined time has elapsed. Therefore, it is not necessary to use a plurality of terminals to detect the connection of the external device, and the cost can be reduced.

  In addition, preferably, when any one of a plurality of external devices is connected to the device main body, by changing the resistance value of the resistance of each external device, the connected external devices are provided with a difference in discharge time. Since the device can be discriminated, it is not necessary to provide a plurality of connectors and the cost can be reduced.

  FIG. 1 is a diagram showing an external device connection detection device according to an embodiment of the present invention. FIG. 1 (A) shows a device body, and FIG. 1 (B) connects an external expansion device, which is an optional device, to the device body. Shows the state.

  In FIG. 1A, for example, a control circuit 2 is built in the apparatus main body 1 side for image formation of the image forming apparatus, and an input / output terminal 3 as a first terminal of the control circuit 2 is a connector 4. Connected to one terminal. A capacitor C as charge storage means is connected between the input / output terminal 3 and a ground potential line as a reference potential. As the charge accumulating means, a device capable of accumulating charges using other semiconductors may be used.

  An external expansion device 10 shown in FIG. 1B is, for example, a finisher, and includes a control circuit 11. An input / output terminal 12 as a second terminal of the control circuit 11 is connected to one terminal of the connector 13. ing. A resistor R is connected between the input / output terminal 12 and the ground line. The connector 13 is connected to the connector 4 of the device body 1.

  FIG. 2 is a conceptual diagram for explaining the operation of the external device connection detection device according to the embodiment of the present invention. FIG. 3 is a flowchart for explaining the operation of the external connection detection device according to the embodiment of the invention. .

Assume that an external expansion device 10 is connected to the device main body 1 via connectors 4 and 13 as shown in FIG. The control circuit 2 of the device main body 1 executes processing based on the external extension device connection detection flowchart shown in FIG. In step (abbreviated as SP in the figure) SP1, the input / output terminal 3 is set to the output mode, and in step SP2, the input / output terminal 3 is set to “H” as the first level as shown in FIG. A level signal is output to charge the capacitor C. Charge is accumulated in the capacitor C by this charging. The electric charge stored in the capacitor C is discharged from the connectors 4 and 13 through the resistor R as shown in FIG. 2B. In step SP3, the control circuit 2 sends an “H” level signal to the input / output terminal 3. Is stopped and the high impedance (Hi-Z) mode is set. In step SP4, the control circuit 2 sets a detection waiting time. This detection waiting time is a time determined by the time constant of the capacitor C and the resistor R, and the level after the electric charge accumulated in the capacitor C is discharged by the resistor R and the potential of the input / output terminal 3 is stabilized. The time is compensated so that it can be read. In step SP5, it is determined whether or not the waiting time has elapsed. If not, the process waits until it elapses.

  When determining that the waiting time has elapsed, the control circuit 2 sets the input / output terminal 3 to the input mode as shown in FIG. 2C and takes in the voltage in step SP6. Then, in step SP7, the voltage is read. In step SP8, it is determined whether or not the logical value level of the read voltage is the “L” level as the second level due to the discharge of the capacitor C. To do. If it is determined that the level is “L”, it is determined that the external expansion device 10 is connected. When the external expansion device 10 is not connected, the electric charge stored in the capacitor C is not discharged, so the voltage read in step SP7 is at the “H” level, so that the external expansion device 10 is connected. Can be determined.

  As described above, according to this embodiment, after the input / output terminal 3 is set to the “H” level and the capacitor C is charged, the electric charge accumulated in the capacitor C is discharged by the resistor R of the external expansion device 10. The terminal voltage after the predetermined discharge time is compensated and switched to the input mode is read, and the two types of states of “H” and “L” levels are discriminated to determine whether the external expansion device 10 is connected or not. it can.

  After determining whether or not an external expansion device is connected, the input / output terminals 3 and 12 can be used as input / output ports for transmitting and receiving normal operation signals.

  FIG. 4 is a diagram showing an external device connection detection device according to another embodiment of the present invention, and FIG. 5 is a flowchart showing the operation of the external device connection detection device according to another embodiment of the present invention. In FIG. 4, only the input / output terminals 12a and 12b and the resistors R1 and R2 are shown with respect to the external expansion devices 10a and 10b, and the other configurations are the same as those of the external expansion device 10 in FIG. Yes.

  In this embodiment, either the external expansion device 10a which is the first device shown in FIG. 4A or the external expansion device 10b which is the second device shown in FIG. 4B is connected to the device main body 1. It is to determine whether or not. These external expansion devices 10a and 10b are configured in the same manner as the external expansion device 10 shown in FIG. 1B, but a resistor R1 is connected between the input / output terminal 13a of the external expansion device 10a and the ground. A resistor R2 is connected between the input / output terminal 13b of the external expansion device 10b and the ground, and the resistors R1 and R2 have different resistance values.

  In step SP11 shown in FIG. 5, the control circuit 2 of the device main body 1 sets the input / output terminal 3 to the output mode and outputs an “H” level signal. If the external expansion device 10a shown in FIG. 4A is connected to the device body 1, for example, the charge charged in the capacitor C is discharged by the resistor R1. In step SP12, the input / output terminal 3 is set to the high impedance mode. In step SP13, a first device detection waiting time is set in order to detect the external expansion device 10a. This waiting time is a time determined by the time constant between the capacitor C and the resistor R1.

  In step SP14, it is determined whether or not the waiting time has elapsed. If the waiting time has not elapsed, the process waits until it elapses. If it has elapsed, in step SP15, the input / output terminal 3 is set to the input mode and the voltage is read. In step SP16, it is determined whether or not the read voltage level is the “L” level. If it is determined that the level is “L” level, it is determined that the external expansion device 10a as the first device is connected to the device main body 1.

  In step SP16, if the read voltage level is not “L” level, it is determined that the device is not the external expansion device 10a. In step SP17, the input / output terminal 3 is set to the output mode again and set to the “H” level. Capacitor C is charged. When the charging is completed, in step SP18, the input / output terminal 3 is set to the high impedance mode. Assuming that the external expansion device 10b is connected to the device body 1, the charge charged in the capacitor C is discharged by the resistor R2. In step SP19, a second device detection waiting time is set in order to detect the external expansion device 10b. This waiting time is a time determined by the time constant between the capacitor C and the resistor R2.

  In step SP20, it is determined whether or not the waiting time has elapsed. If the waiting time has not elapsed, the process waits until it elapses, and if it has elapsed, in step SP21, the input / output terminal 3 is set to the input mode and the voltage is read. In step SP22, it is determined whether or not the read voltage level is “L” level. If it is determined that the level is “L” level, it is determined that the external expansion device 10 b as the second device is connected to the device body 1. If it is determined in step SP22 that the level is not “L” level, it is determined that neither the external expansion device 10a nor 10b is connected to the device main body 1.

  As described above, according to this embodiment, the charge / discharge time parameter is changed by changing the resistance values of the resistors R1 and R2 connected to the external expansion devices 10a and 10b connected to the device body 1. It is possible to detect which of the plurality of external expansion devices 10a and 10b is connected by detecting the potential of the input / output terminal 3 of the device body 1.

  In the example shown in FIGS. 4 and 5, the example in which one of the two external expansion devices 10a and 10b is connected to the device main body 1 has been described. However, one of the three or more external expansion devices is connected to the device. You may make it connect with a main body. In that case, the resistance values of the resistors connected between the input / output terminals of each external extension device and the ground may be made different.

  Furthermore, in the above description, the present invention is applied to the image forming apparatus. However, the present invention can also be applied to detecting whether an external device is connected to another electronic device.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

It is a figure which shows the external apparatus connection detection apparatus of one Embodiment of this invention. It is a conceptual diagram for demonstrating operation | movement of the external apparatus connection detection apparatus in one Embodiment of this invention. It is a flowchart which shows operation | movement of the external apparatus connection detection apparatus in one Embodiment of this invention. It is a figure which shows the external apparatus connection detection apparatus in other embodiment of this invention. It is a flowchart which shows operation | movement of the external apparatus connection detection apparatus in other embodiment of this invention.

Explanation of symbols

  1 equipment body, 2, 11 control circuit, 3, 12, 12a, 12b input / output terminals, 4, 13 connectors, 10, 10a, 10b external expansion equipment, C capacitors, R, R1, R2 resistors.

Claims (6)

An external device connection detection device that detects whether an external device is connected to the device body,
A terminal to which the external device is connected;
Charge storage means connected between the terminal and a reference potential line;
The charge storage means is charged, the potential of the terminal is determined after a predetermined time has elapsed, and if it is the first potential, it is determined that the external device is not connected, the charge storage means is discharged and the first An external device connection detection device comprising: control means for determining that the external device is connected if the second potential is different from the first potential. An external device connection detection device that detects whether an external device is connected to the device body,
The terminal of the device main body and the terminal of the external device are connectable, and a resistor is connected between the terminal of the external device and a reference potential line,
Charge storage means connected between the terminal of the device body and a reference potential line;
Charge the charge storage means, determine the potential of the terminal of the device body after a predetermined time, and if it is the first potential, determine that the external device is not connected, discharge the charge storage means An external device connection detection device comprising: control means for determining that the external device is connected if the second potential is different from the first potential.   The external device connection detection apparatus according to claim 1, wherein the predetermined time is a time determined by a time constant between the resistance of the external device and the charge storage unit. A plurality of the external devices are prepared, and the resistors connected between the respective terminals and the reference potential line are selected so as to have different resistance values,
The control means charges the charge storage means, determines the potential of the terminal of the device main body after elapse of time determined by the time constant between the resistance of the external device connected to the device main body and the charge storage means, The external device connection detection apparatus according to claim 1 or 2, wherein which external device is connected is determined.   The control means transmits / receives an operation signal to / from the external device via the terminal of the device main body and the terminal of the external device after finishing the connection determination of the external device. 5. The external device connection detection device according to any one of 1 to 4.   An image forming apparatus comprising the external device connection detection device according to claim 1.

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