JP5298057B2 - Power saving system - Google Patents

Description

 The present invention relates to a power saving system.

  Generally, an image forming apparatus such as a printer, a copier, or a multifunction peripheral has a function of shifting to a power saving mode (sleep mode) in order to suppress wasteful power consumption when external input is not received for a certain period of time. Yes. In addition, an image forming apparatus to which an external optional device (for example, a paper feeder or a finisher) can be mounted has a function of shifting the optional device to the power saving mode when the image forming device itself shifts to the power saving mode.

  Hereinafter, a mechanism in which the image forming apparatus A shifts the option apparatus B to the power saving mode will be described with reference to FIG. In the following description, it is assumed that the optional device B is a paper feeder that is a paper feed option. As shown in FIG. 2A, when the option device B is attached to the image forming apparatus A, the engine CPU 10 built in the image forming apparatus A and the option CPUs 20 and 30 built in the option apparatus B are connected. It is connected so that it can communicate.

  Here, the engine CPU 10 is a CPU that performs overall control of the print engine of the image forming apparatus A. The print engine refers to a group of mechanisms that print (form) an image on recording paper (recording medium) based on image data. The print engine uses a sheet feeding conveyance mechanism that feeds and conveys recording paper, and an electrophotographic system. The toner image forming mechanism that forms toner images of each color based on the image data on the surface of the photoreceptor, the transfer mechanism that transfers the toner image to the recording paper, the fixing mechanism that fixes the toner image on the recording paper, and the recording paper after image fixing are removed. A paper discharge transport mechanism for transporting paper is included.

  On the other hand, the option CPU 20 is a CPU that controls the rotation of a paper feed roller that picks up, for example, A4 size recording paper stored in an A4 paper feed cassette of the option device B one by one and feeds it to the image forming apparatus A. is there. The option CPU 30 is a CPU that controls the rotation of a paper feed roller that picks up A3 size recording paper stored in an A3 paper feed cassette of the option device B one by one and feeds it to the image forming apparatus A, for example. is there.

  These CPUs are connected by a three-wire serial communication bus with the engine CPU 10 as a master and the option CPUs 20 and 30 as slaves. The serial communication bus includes a clock communication line CL1 for supplying a communication clock from the engine CPU 10 to the option CPUs 20 and 30, a transmission data communication line CL2 for transmitting transmission data from the engine CPU 10 to the option CPUs 20 and 30, and an engine. The CPU 10 includes three communication lines including a reception data communication line CL3 for receiving reception data from the option CPUs 20 and 30.

  Further, the engine CPU 10 and the option CPU 20 are connected via a selection signal communication line SL1, and the engine CPU 10 and the option CPU 30 are connected via a selection signal communication line SL2. The engine CPU 10 transmits an option selection signal to the option CPU 20 via the selection signal communication line SL1 when the A4 size recording paper is required, and sets the selection signal communication line SL2 when the A3 size recording paper is required. Then, an option selection signal is transmitted to the option CPU 30.

 Upon receiving the option selection signal, the option CPUs 20 and 30 read the transmission data transmitted via the transmission data communication line CL2 as valid data, and perform rotation control of the paper feed roller in accordance with an instruction from the engine CPU 10, If no option selection signal is input, the transmission data transmitted via the transmission data communication line CL2 is discarded as invalid data.

 These option CPUs 20 and 30 are operated by the power supply voltage V1 supplied from the image forming apparatus A. Therefore, when a factor for shifting to the power saving mode occurs on the image forming apparatus A side, the engine CPU 10 stops the supply of the communication clock and the power supply voltage V1 to the option CPUs 20 and 30, so that the option CPUs 20 and 30, that is, The optional device B is shifted to the power saving mode.

 On the other hand, when the A4 paper feed cassette or the A3 paper feed cassette is opened and closed in the option device B in the power saving mode, it is presumed that the recording paper has been replenished by the user, so the image forming apparatus A (engine CPU 10). In addition, it is necessary to return the option device B (option CPUs 20 and 30) from the power saving mode and transmit status information such as the remaining amount of paper from the option CPUs 20 and 30 to the engine CPU 10.

 FIG. 2B is a diagram showing a mechanism for transmitting the detection result to the engine CPU 10 when the opening / closing of the A4 paper feed cassette or the A3 paper feed cassette is detected in the option device B. In the figure, symbol SW1 is an A4 cassette open / close detection switch that is turned on / off in response to opening / closing of the A4 paper cassette, and symbol SW2 is an A3 cassette open / close detection switch that is turned on / off in response to opening / closing of the A3 paper cassette. It is.

 In the option device B, one end of the A4 cassette open / close detection switch SW1 is connected to the ground line, and the other end is connected to one end of the resistor R1 and the base terminal of the n-type transistor T1. The emitter terminal of the transistor T1 is connected to the ground line, and the collector terminal is connected to one end of the resistor R3. Similarly, one end of the A3 cassette open / close detection switch SW2 is connected to the ground line, and the other end is connected to one end of the resistor R2 and the base terminal of the n-type transistor T2. The emitter terminal of the transistor T2 is connected to the ground line, and the collector terminal is connected to one end of the resistor R3.

  A power supply voltage V2 supplied from the image forming apparatus A is applied to the other ends of the resistors R1, R2, and R3. Unlike the power supply voltage V1 described above, the power supply voltage V2 is a power supply voltage that is constantly supplied from the image forming apparatus A even in the power saving mode. One end of the resistor R3 is connected to the engine CPU 10 via a return signal communication line RL.

  In such a circuit configuration, when both the switches SW1 and SW2 are on (when both paper cassettes are closed), the potential of the return signal communication line RL is held at a high level (power supply voltage V2). Is done. On the other hand, when at least one of the switches SW1 and SW2 is changed to an off state (when one paper feed cassette is opened), the potential of the return signal communication line RL is changed to a low level (ground level). When both the switches SW1 and SW2 return to the on state again, the potential of the return signal communication line RL returns to the high level.

That is, during the power saving mode, the engine CPU 10 monitors the potential of the return signal communication line RL as a return signal, and when the potential (return signal) transitions from a high level to a low level, the power saving mode return factor ( It recognizes that the paper feed cassette has been opened / closed and returns from the power saving mode, and also returns the option device B from the power saving mode (resuming the supply of the communication clock and power supply voltage V1 to the option CPUs 20 and 30).
Japanese Patent Application Laid-Open No. 2004-151561 discloses a technique that realizes a response of status information requested from a network with as little energy as possible and at a low cost even when the image forming apparatus is in a sleep state.

JP 2004-130525 A

  As can be seen from the configuration shown in FIGS. 2A and 2B, conventionally, as an I / F signal line connecting the image forming apparatus A and the option apparatus B, as shown in FIG. The first power supply line PL1 for supplying the power supply voltage V1, the second power supply line PL2 for always supplying the power supply voltage V2, the return signal communication line RL, the clock communication line CL1, and the transmission data communication line CL2 The reception data communication line CL3, the selection signal communication lines SL1 and SL2, and the ground line GL are necessary. In FIG. 2C, the clock communication line CL1, the transmission data communication line CL2, the reception data communication line CL3, and the selection signal communication lines SL1 and SL2 are not shown.

As the number of I / F signal lines increases, the cost naturally increases. However, in the configuration of the image forming apparatus A and the option apparatus B described above, the number of I / F signal lines is reduced while maintaining a necessary communication function. It is difficult to reduce the cost.
The present invention has been made in view of the above-described circumstances, and can save power by reducing the number of I / F signal lines connecting the two devices while maintaining a necessary communication function between the master device and the slave device. The purpose is to provide a system.

In order to solve the above problem, a power saving system according to the present invention is connected to a master device and the master device via an I / F signal line, and shifts to a power saving mode in accordance with control by the master device. In a power saving system including a slave device, a continuous power supply line for constantly supplying a power supply voltage from the master device to the slave device, which is included in the I / F signal line, is connected from the slave device to the master device. Commonly used as a communication line for notifying the occurrence of a power saving mode return factor, the slave device is connected to the slave device side end of the constant power supply line according to the occurrence of the power saving mode return factor. And a switching circuit for switching electrical connection / disconnection between the common potential line and the common potential line. The master device has a power supply voltage for constant power supply applied to one end and the other end connected to the constant power supply line. And a voltage detection circuit that detects a voltage between terminals of the resistor and outputs the detection result as a signal indicating whether or not the power saving mode return factor has occurred. It is characterized by that.

In the power saving system, the master device is an image forming device, and the slave device is an optional device attached to the image forming device.

 According to the power saving system of the present invention, the communication line for notifying the occurrence of the power saving mode return factor can be deleted from the I / F signal line connecting the master device and the slave device. The function of notifying the presence or absence of the occurrence of the power saving mode return using the power supply line can be maintained. That is, according to the present invention, it is possible to reduce the number of I / F signal lines connecting the two devices while maintaining a necessary communication function between the master device and the slave device, thereby reducing the cost. It becomes possible.

1 is a schematic configuration diagram of a power saving system in the present embodiment. It is a structure schematic diagram of the conventional power saving system.

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, for convenience of explanation, as in FIG. 2, a power saving system in which the image forming apparatus A is a master apparatus and the option apparatus B attached to the image forming apparatus A is a slave apparatus will be described as an example.

 FIG. 1A is a schematic configuration diagram of a power saving system according to the present embodiment. In order to distinguish from the conventional example of FIG. 2, the reference numeral of the image forming apparatus is A1, and the reference numeral of the optional apparatus is B1. . In FIG. 1A, the same components as those in FIG.

  As shown in FIG. 1A, the optional device B1 in the present embodiment includes an A4 cassette opening / closing detection switch SW1 that is turned on / off according to the opening / closing of the A4 sheet feeding cassette and the opening / closing of the A3 sheet feeding cassette. A switching circuit including an A3 cassette opening / closing detection switch SW2 to be turned on / off, resistors R1 and R2, and n-type transistors T1 and T2 is provided. This switching circuit is connected to the optional device side end (slave device side end) of the second power supply line PL2 (always power supply line) depending on whether or not a power saving mode return factor (in this case, opening and closing of the paper feed cassette) occurs. ) And the ground line (common potential line).

  The specific circuit configuration of the switching circuit as described above is as follows. That is, one end of the A4 cassette open / close detection switch SW1 is connected to the ground line, and the other end is connected to one end of the resistor R1 and the base terminal of the transistor T1. The emitter terminal of the transistor T1 is connected to the ground line, and the collector terminal is connected to the end of the second feeder line PL2 on the option device side. In addition, the other end of the resistor R1 is also connected to the optional device side end of the second feeder line PL2.

 Similarly, one end of the A3 cassette open / close detection switch SW2 is connected to the ground line, and the other end is connected to one end of the resistor R2 and the base terminal of the transistor T2. The emitter terminal of the transistor T2 is connected to the ground line, and the collector terminal is connected to the end of the second feeder line PL2 on the option device side. Further, the other end of the resistor R2 is also connected to the end portion of the second feeder line PL2 on the option device side.

 On the other hand, in the image forming apparatus A1 in the present embodiment, the power supply voltage V2 for constant power supply is applied to one end, and the other end is connected to the image forming apparatus side end (master apparatus side end) of the second power supply line PL2. A resistor R4, and a differential amplifier (voltage detection circuit) Amp that detects the voltage between the terminals of the resistor R4 and outputs the detection result to the engine CPU 10 as a signal indicating whether or not a power-saving mode return factor has occurred. I have.

 In the power saving system configured as described above, when both the switches SW1 and SW2 are in the on state (when both the paper cassettes are closed), the transistors T1 and T2 are in the off state. The end of the two feeder lines PL2 on the option device side is electrically disconnected from the ground line. In this state, almost no current flows through the resistor R4 (more precisely, a weak current corresponding to the leakage current of the transistors T1 and T2 flows), and the voltage across the resistor R4 becomes extremely small. For this reason, the output signal level of the differential amplifier Amp is also substantially at the ground level (low level).

 On the other hand, when at least one of the switches SW1 and SW2 is turned off (when one paper feed cassette is opened), one of the transistors T1 and T2 is turned on. The device side end is electrically connected to the ground line. In this state, a relatively large current flows through the resistor R4 (more precisely, a current corresponding to a value obtained by dividing the power supply voltage V2 by the resistance value of the resistor R4 flows) between the terminals of the resistor R4. The voltage becomes relatively large (approximately equal to the power supply voltage V2). For this reason, the output signal level of the differential amplifier Amp is also substantially equal to the power supply voltage V2 (high level). When both the switches SW1 and SW2 return to the on state again, the output signal level of the differential amplifier Amp returns to the low level.

 That is, the engine CPU 10 of the image forming apparatus A1 monitors the output signal level of the differential amplifier Amp during the power saving mode, and when the output signal level transitions from the low level to the high level, the power saving mode return factor Recognizing that (paper cassette opening / closing) has occurred and returning from the power saving mode, the option device B1 can be returned from the power saving mode.

  As described above, according to the present embodiment, the image forming apparatus A1 is connected to the image forming apparatus A1 via the I / F signal line, and the option of shifting to the power saving mode according to the control by the image forming apparatus A1. In the power saving system provided with the device B1, whether or not a power saving mode return factor is generated from the optional power supply B1 to the image forming apparatus A1 through the constant power supply line (second power supply line PL2) included in the I / F signal line. It is possible to realize a configuration in which a communication line for notification is shared.

 By realizing such a configuration, as shown in FIG. 1B, the presence / absence of occurrence of the power saving mode return factor is notified from the I / F signal line connecting the image forming apparatus A1 and the option apparatus B1. Communication line (return signal communication line RL in FIG. 2) can be deleted, while the power supply mode (second power supply line PL2) is always used to notify the presence or absence of a power saving mode return factor. The function can be maintained. That is, according to the present embodiment, it is possible to reduce the number of I / F signal lines connecting between the two apparatuses while maintaining a necessary communication function between the image forming apparatus A1 and the option apparatus B1. Can be achieved.

  In the above embodiment, the power saving system in which the image forming apparatus A1 is the master apparatus and the option apparatus B1 is the slave apparatus has been described as an example. However, the present invention is not limited thereto, and the master apparatus and the I / F signal line are connected. The present invention can be applied to any power saving system including a slave device that is connected to the master device via the slave device and shifts to the power saving mode in accordance with control by the master device.

 Further, the switching circuit provided in the option device B1 (slave device) may be appropriately changed according to the type of the option device and the power saving mode return factor to be detected. In other words, any switching circuit can be used as long as it switches electrical connection / disconnection between the end of the power supply line on the slave device side and the common potential line according to the occurrence of the power saving mode return factor. A circuit configuration may be used.

 A1... Image forming apparatus (master apparatus), B1... Option apparatus (slave apparatus), PL2... Second feeding line (always feeding line), SW1... A4 cassette opening / closing detection switch, SW2. , R4, resistor, T1, T2, transistor, Amp, differential amplifier (voltage detection circuit)

Claims (2)

In a power saving system comprising a master device and a slave device that is connected to the master device via an I / F signal line and shifts to a power saving mode according to control by the master device,
Notify the presence / absence of occurrence of a power saving mode return factor from the slave device to the master device through a constant power supply line included in the I / F signal line for constantly supplying power supply voltage from the master device to the slave device. in common as a communication line for,
The slave device includes a switching circuit that switches electrical connection / disconnection between the slave device side end of the constant power supply line and a common potential line depending on whether or not the power saving mode return factor is generated,
The master device detects a voltage between the terminals of the resistor, the resistor having a power supply voltage for constant power supply applied to one end and the other end connected to the master device side end of the constant power supply line, A voltage detection circuit that outputs a detection result as a signal indicating whether or not the power saving mode return factor has occurred.
A power-saving system characterized by that . The power saving system according to claim 1, wherein the master device is an image forming device, and the slave device is an optional device attached to the image forming device.

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