JP2011183701A - Image forming apparatus corresponding to usb - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus corresponding to USB which can normally operate a USB device without restraining the OFF/ON operation of a power supply and can certainly perform a control without generating a fault even when various USB devices are connected. <P>SOLUTION: Voltage control circuits 55 are connected to VBUS lines for applying a power supply voltage to USB devices 100a and 101a, respectively. The voltage control circuit 55 performs the control so as to turn on or turn off the power supply voltage. A voltage detection circuit 56 has the function of supervising the power supply voltage applied to the VBUS line, and transmits a detection signal to the voltage control circuit 55 when the power supply voltage drops below a predetermined voltage. Then, the voltage control circuit 55 turns off the power supply voltage in an instant when receiving from the voltage detection circuit 56 the detection signal showing that the power supply voltage has dropped below the predetermined voltage. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a USB interface.

  The USB (Universal Serial Bus) standard is frequently used as an interface (I / F) for connecting a host-side device having a USB connector and its peripheral devices. USB is a standard concerning a data transmission path established as a communication interface between a personal computer (USB host) and peripheral devices. In USB, data transfer is performed by the USB host side device, and peripheral devices transmit and receive data in response to requests from the USB host side device.

  USB has also been introduced in electronic devices other than personal computers. For example, there are many models in which a USB host port is mounted as a standard in an image forming apparatus (multi-function printer, laser printer, etc.). In addition to the USB memory, various USB-compatible devices can be connected to the USB host port via a USB connection cord, and optional USB devices such as an IC card R / W, a digital camera, and an SD card reader are also connected. It is like that.

  By the way, in such an image forming apparatus, there is a problem that when the IC card R / W is connected, the IC card R / W is not recognized by the power off / on operation of the apparatus. This is because when the power of the device is turned off, the voltage is not instantaneously turned off but turned off with a gradual falling waveform. Therefore, if the on operation is performed without the voltage being lowered, the IC card R / W It was found that the cause was an abnormal communication state in the network. Therefore, in such a power-off / on operation, the time interval until the on-operation is set at a predetermined time, and the on-operation is performed after the voltage at the time of off sufficiently decreases.

  As a method for solving such a problem of the USB device, a forced operation such as a hard reset is performed on the USB device. For example, in Patent Document 1, an operation instruction signal for instructing an operation to a USB device is transmitted from the host of the USB connection system through the VBUS line in the USB cable, and the transmitted operation instruction signal is transmitted to the USB device of the USB connection system. A technique is disclosed in which a predetermined operation is detected and a standard USB cable is used as it is, and a forced operation control such as a hard reset is executed from a host to a USB device.

  However, there is a problem that it is difficult for all users to make it thorough with the conventional measures for notifying users that the power-off / on interval has been provided for a predetermined time. Further, the technique disclosed in Patent Document 1 does not function unless both the USB device and the host-side device are compatible, and does not cope with the above-described problems when the power is turned off / on.

  Therefore, the present invention can normally operate the USB device without restricting the power off / on operation, and can reliably control without causing any trouble even when various USB devices are connected. An object of the present invention is to provide a USB-compatible image forming apparatus.

According to a first aspect of the present invention, there is provided a USB transmission / reception unit for transmitting and receiving data to and from a USB device connected to a USB connector via a connection line and supplying a power supply voltage via a VBUS line. A control unit that controls the USB device via the USB transmission / reception unit, a voltage detection unit that detects the power supply voltage, an on / off control of the power supply voltage connected to the VBUS line, and the power supply voltage And a voltage control means for turning off the power supply voltage based on a detection signal from the voltage detection means indicating that the voltage drops below a predetermined voltage.
According to a second aspect of the present invention, in the USB-compatible image forming apparatus according to the first aspect, the voltage control unit uses a detection signal from the voltage detection unit to indicate that the power supply voltage has risen above a predetermined voltage. Based on this, the power supply voltage is turned on.
According to a third aspect of the present invention, in the USB-compatible image forming apparatus according to the first or second aspect, the control unit registers registration means for registering identification data of the connectable USB device, and the connected USB. Determining means for determining whether the identification data of the device matches the registered identification data, and when the identification data is determined not to match, the voltage control means is controlled to be turned on after being turned off. Features.
A fourth aspect of the present invention is the USB-compatible image forming apparatus according to the first or second aspect, wherein the control unit turns off the voltage control unit when a packet response is not transmitted from the connected USB device. It is characterized in that it is controlled to be turned on later.
A fifth aspect of the present invention is the USB-compatible image forming apparatus according to any one of the first to fourth aspects, wherein the control unit includes setting means for setting the power supply voltage to be turned off in an energy saving mode, When the power supply voltage is turned off, the voltage control means is controlled to be turned off when the energy saving mode is entered.
A sixth aspect of the present invention is the USB-compatible image forming apparatus according to the fifth aspect, wherein the setting unit is capable of setting an operation time of a device, and the control unit is configured to set the operation time within the set operation time. The voltage control means is controlled to be turned on.

  Since the present invention has the above-described configuration, the power supply voltage supplied to the USB device via the VBUS line is turned off when the voltage drops below a predetermined voltage, so that the main power supply of the apparatus is turned off / on. After the power supply voltage is instantaneously turned off, it is turned on, and a normal off / on operation can be performed.

1 is an overall perspective view of an image forming apparatus according to an embodiment of the present invention. 1 is a side sectional view of a central portion of an image forming apparatus. FIG. 2 is a block diagram of a main part of a control system of the image forming apparatus. It is a processing flow regarding control of the power supply voltage of the VBUS line when the main power switch is turned on / off. It is a graph showing a falling waveform of the VBUS power when main power is off (time t _0). It is a processing flow at the time of connecting and registering a USB device. It is a processing flow regarding data transmission / reception when a USB device is connected. It is a processing flow regarding the power supply setting to the USB device when the energy saving mode is set.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is an overall perspective view of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, an image forming apparatus 100 includes an image forming unit 1 that forms an image by a so-called electrophotographic method based on a reading signal of the document, and a document Automatic document feeding unit 2 for automatically sending and reading, reverse feeding mechanism 3 for reversing the moving direction of the paper printed on one side for duplex printing, paper feeding unit 4 and various printing An operation display unit 5 that performs setting and displays setting results and the like is provided. The operation console provided with the operation display unit 5 is provided with a USB connector 6 on the front surface, so that a USB device such as an IC card R / W or an SD card reader is directly connected to the outside of the USB memory. It has become. A USB device such as a digital camera is also connected using a USB connection cord.

  FIG. 2 is a cross-sectional side view of the central portion of the image forming apparatus. In FIG. 2, the image forming unit 1 includes a photosensitive drum 11 configured by providing an organic semiconductor layer that is a photoconductive substance on the surface of an aluminum cylinder, and a conductive material for uniformly charging the organic semiconductor layer of the photosensitive drum 11. Development unit 14 for forming an electrostatic latent image on a photosensitive drum including a photosensitive elastic roller 12, a laser light source 13 and its optical system, and developing the toner by attaching toner to the electrostatic latent image on the photosensitive drum 11. A developing device 15 for performing the transfer, a transfer device 16 for transferring the toner image developed on the photosensitive drum 11 to the paper P, a fixing roller 17 for fixing the toner image by sandwiching the paper P to which the toner image has been transferred, and a pressure roller. 18, a static eliminator 19 for removing the charge of the photosensitive drum 11 and a paper discharge roller 20.

  The reversal paper feeding mechanism 3 has a reversal conveyance path 31 and a drawing conveyance path 32. When the switching device 34 guides the paper P to the reverse conveyance mechanism 3 side, the reverse conveyance mechanism 31 is once conveyed to the drawing conveyance path 32 side. When the conveyance is completed, the switching unit 34 blocks the entrance portion of the pull-in conveyance path 32, and the reversing roller 33 rotates in the direction of the arrow, so that it is conveyed toward the reverse conveyance path 31 and is again formed by the conveyance roller 35. It is conveyed to part 1.

  The paper P stored in the cassettes 41 and 42 of the paper feed unit 4 is fed by the paper feed rollers 41a and 42a, passed through the image forming unit 1 by the transport rollers 21 and 22, and the switch 23 is on the paper discharge roller 20 side. Is guided to the paper discharge unit 24 by the paper discharge roller 20.

  The manual paper feed unit 43 is a paper feed unit that can manually feed special-size paper, and is fed to the image forming unit 1 via a paper feed roller 44.

  FIG. 3 is a block diagram of the main part of the control system of the image forming apparatus. The control unit 50 includes an information processing device such as a CPU and controls the entire image forming apparatus. The control unit 50 performs control processing such as writing processing and reading processing on the USB device connected to the USB connector 6. The operation display unit 5 performs user operation inputs and various data display using operation keys and a liquid crystal display panel. The image forming unit 51 performs an image forming process on a sheet as described above, and performs a series of processes such as paper feeding, toner image forming, transfer, fixing, and paper discharging. The storage unit 52 includes a non-volatile memory that stores information such as various data necessary for control processing, various parameters, and history data, a work area for control processing, and a volatile memory that is used for storing image data. . In addition, a main power switch 53 for turning on / off the power supply of the entire apparatus is provided.

  The control unit 50 is connected to a USB transmission / reception unit 54 that transmits / receives data to / from a USB device. The USB transmission / reception unit 54 transmits four data lines, that is, a GND line, a D1-line, a D1 + line, and a VBUS line. It is connected to a USB device via a path. Then, a power supply voltage is supplied from the apparatus side to the USB device through the VBUS line. In this example, two USB devices 100a and 101a are connected in a line to transmit / receive data to / from each USB device.

  A voltage control circuit 55 is connected to each VBUS line that supplies a power supply voltage to each USB device, and the voltage control circuit 55 controls the power supply voltage to be turned on or off. The voltage detection circuit 56 has a function of monitoring the power supply voltage supplied to the VBUS line. When the power supply voltage drops below a predetermined voltage or when the power supply voltage rises above a predetermined voltage, a detection signal is sent to the voltage control circuit 55. Send to. When the voltage control circuit 55 receives a detection signal indicating that the power supply voltage has dropped below the predetermined voltage from the voltage detection circuit 56, the voltage control circuit 55 turns off the power supply voltage and outputs a detection signal indicating that the power supply voltage has risen above the predetermined voltage. When receiving from the voltage detection circuit 56, on / off control is performed to turn on the power supply voltage. In this example, since the voltage control circuit 55 is provided for each USB device, the power supply voltage supplied to the USB device can be individually turned on / off.

  The control unit 50 includes a USB data processing unit 501, an on / off control unit 502, a registration processing unit 503, a determination unit 504, and a setting unit 505. The USB data processing unit 501 performs data processing such as data write processing and read processing on the connected USB device. The on / off control unit 502 performs on / off control of the voltage control circuit 55 to perform reset processing of the USB device and processing at the time of setting the energy saving mode. The registration processing unit 503 performs registration processing of the identification data of the USB device when the USB device is connected. The determination unit 504 determines whether the registered identification data of the USB device matches the reacquired identification data. For example, a vendor ID or a product ID is used as the identification data. The setting unit 505 performs setting processing related to the energy saving mode such as setting related to the supply stop of the power supply voltage to the USB device in the energy saving mode and setting the operation time of the apparatus.

  FIG. 4 is a processing flow relating to control of the power supply voltage of the VBUS line when the main power switch is turned on / off. When the main power switch 53 of the image forming apparatus is turned on (S100), the apparatus activation process is started and the power supply of the VBUS line is started (S101), but the voltage control circuit 55 remains in the off state. The supply stop state of the power supply voltage is maintained for the USB device.

  When the power supply to the VBUS line is started, the voltage detection circuit 56 monitors the power supply voltage and checks whether the power supply voltage has risen above a predetermined value (S102). When it is detected that the voltage detection circuit 56 has risen to a predetermined value or more, a detection signal is output to the voltage control circuit 55, and the voltage control circuit 55 is turned on based on the detection signal from the voltage detection circuit 56 (S103). ), The power supply voltage is supplied to the USB device (S104). When the power supply voltage is supplied, the USB device starts operation and starts data transmission / reception with the USB transmission / reception unit 54.

  Next, when the main power switch 53 is turned off (S105), the power supply voltage supplied to the VBUS line also decreases. However, the voltage detection circuit 56 monitors the power supply voltage, and the power supply voltage drops below a predetermined value. Is checked (S106). When it is detected that the voltage detection circuit 56 has fallen below a predetermined value, a detection signal is output to the voltage control circuit 55, and the voltage control circuit 55 is turned off based on the detection signal from the voltage detection circuit 56 (S107). The power supply voltage supplied to the USB device is immediately stopped (S108).

  The power supply voltage supplied to the USB device is reliably stopped by the on / off control of the power supply voltage as described above, and the normal on / off operation can be performed on the USB device.

Figure 5 is a graph showing a falling waveform of the VBUS power when the main power-off of the conventional device (time t ₀₎ (FIG. 5 (a)) and when the main power-off of the device according to the present invention (time t ₀₎ It is a graph (FIG.5 (b)) which shows the falling waveform of VBUS power supply. In the conventional device, the power supply voltage gradually decreases, and it takes 10 seconds or more for the 5V power supply voltage to drop to about 0.2V. When the main power is turned off, it takes 10 seconds or more. If the main power is not turned on, the USB device cannot be operated normally. On the other hand, in the apparatus according to the present invention, the power supply voltage is instantaneously decreased, and it takes less than 1 second for the power supply voltage of 5V to decrease to about 0.2V. Therefore, the USB device can be normally operated even if the main power supply is turned off immediately after being turned off.

  By using the voltage control circuit provided on the VBUS line in this way, the power supply voltage for the USB device can be reliably turned on / off, so that the power supply voltage can be turned on / off using the voltage control circuit in various other control processes. It can be turned off.

  FIG. 6 is a processing flow when a USB device is connected and registered. First, the main power switch 53 is turned on to supply power to the apparatus (S200). Then, to register the USB device, the operation key of the operation display unit 5 is pressed to shift to the administrator mode (S201), and the USB device to be registered is connected to the USB connector (S202).

  A power supply voltage is supplied from the VBUS line to the connected USB device to transmit / receive data to / from the USB transmission / reception unit 54, and the registration processing unit 503 acquires identification data from the USB device (S203). Since the power supply voltage has risen above the predetermined voltage, the voltage control circuit 55 is in the on state. The registration processing unit 503 displays the acquired identification data on the operation display unit 5 and registers the acquired identification data in the storage unit 52 when the registration OK button is operated (S204).

  When the registration process of the identification data is completed, the on / off control unit 502 controls the power supply voltage supplied to the USB device to be turned on again after turning off the voltage control circuit 55 (S205). The USB device is reset by such an off / on operation of the voltage control circuit 55. Then, the identification data is acquired again from the USB device (S206), and it is checked whether the acquired identification data matches the registered identification data (S207). If they do not coincide with each other, it is checked whether or not the above-described voltage control circuit 55 has been turned off / on three times (S208), and if it has not been executed three times, the off-on operation is again executed (S209). Then, the process returns to step S206, and the USB device identification data is acquired again to check whether it matches the registered identification data. If the identification data does not match even after three checks in step S208, a display indicating that the USB device cannot be used is displayed (S210), and the process ends. If the identification data reacquired in step S207 matches the registered identification data, the process ends, and it is assumed that a normal USB device is connected, and the process proceeds to the next process.

  As described above, since the power supply voltage supplied to the USB device can be instantaneously turned off by the voltage control circuit 55, the USB device is restarted by the reset process that is turned on after the power supply voltage is turned off, the identification data is checked, and normal It is possible to accurately determine whether the device is a USB device.

  FIG. 7 is a processing flow regarding data transmission / reception when a USB device is connected. When the USB device is connected (S300), the USB data processing unit 501 accesses the USB device via the USB transmission / reception unit 54 to start data transmission / reception (S301). After starting the data transmission / reception, it is checked whether there is a packet response from the USB device (S302). If there is no response, the access is repeated and it is checked whether a predetermined time has passed (S303).

  If there is still no response, there is a possibility that the USB device is in a hang-up state, so the reset process is performed by the power supply voltage off / on operation described above. First, it is checked whether the on / off control unit 502 has performed the off / on operation three times (S304). If the on / off control unit 502 has not performed the three times, the power supply voltage is turned off / on with respect to the voltage control circuit 55. Control is performed (S305). After starting up the USB device again, the process returns to step S302, where it is accessed again to check whether there is a packet response. Thereafter, when there is no packet response, the power supply voltage is turned off / on repeatedly. If there is no packet response after three checks, the USB device is displayed as unavailable (S306), and the process ends. If there is a packet response in step S302, the process ends, and the process proceeds to the next process assuming that a normal USB device is connected.

  As described above, since the power supply voltage supplied to the USB device can be instantaneously turned off by the voltage control circuit 55, the USB device is restarted by the reset process that is turned on after turning off the power supply voltage, and the presence or absence of a packet response is checked. It becomes possible to eliminate the hang-up of the USB device and operate normally.

  FIG. 8 is a processing flow related to the power supply setting to the USB device when the energy saving mode is set. First, in order to perform the setting operation, the operation key of the operation display unit 5 is pressed to shift to the administrator mode (S400), and the setting of the energy saving mode is selected (S401). Next, the power supply to the USB device is turned off / on (S402), and the operation time is set (S403).

  After the setting operation, the energy saving mode setting process is started (S404), and it is checked whether the power supply to the USB device is set to OFF (S405). If it is set to OFF, it is checked whether the current time is within the operating time (S406). . If it is not within the operating time, the on / off control unit 502 controls the voltage control circuit 55 to be in the off state, and the supply of the power supply voltage to the USB device is stopped (S407). If the power supply to the USB device is set to ON in step S405 and if it is determined that the operation time is within the operation time in step S406, the voltage control circuit 55 remains in the ON state (S408). Then, after the ON state or OFF state of the power supply voltage is set, the process shifts to the energy saving mode (S409).

  As described above, since the power supply voltage to the USB device can be individually turned off by controlling the voltage control circuit 55, the power supply to the USB device can be stopped in the energy saving mode, and detailed energy saving measures can be taken. . In addition, since the power supply voltage to the USB device can be instantaneously turned off, it is possible to prevent a problem from occurring in the USB device when the supply of the power supply voltage is stopped.

  DESCRIPTION OF SYMBOLS 1 ... Image formation part, 2 ... Automatic document feeding part, 3 ... Reverse feed mechanism, 4 ... Paper feed part, 5 ... Operation display part, 6 ... USB connector, DESCRIPTION OF SYMBOLS 50 ... Control part, 51 ... Image formation part, 52 ... Memory | storage part, 53 ... Main power switch, 54 ... USB transmission / reception part, 55 ... Voltage control circuit, 56 ... Voltage detection circuit.

JP 2006-48496 A

Claims (6)

  A USB transmission / reception unit that transmits / receives data to / from a USB device connected to a USB connector via a connection line and supplies a power supply voltage via a VBUS line, and controls the USB device via the USB transmission / reception unit A control unit; voltage detecting means for detecting the power supply voltage; and on / off control of the power supply voltage connected to the VBUS line, and indicating that the power supply voltage has dropped below a predetermined voltage. A USB-compatible image forming apparatus, comprising: a voltage control unit that turns off the power supply voltage based on a detection signal.   2. The USB compatible device according to claim 1, wherein the voltage control unit turns on the power supply voltage based on a detection signal from the voltage detection unit indicating that the power supply voltage has risen to a predetermined voltage or more. Image forming apparatus.   The control unit includes registration means for registering identification data of the connectable USB device, and determination means for determining whether the identification data of the connected USB device matches the registered identification data. 3. The USB-compatible image forming apparatus according to claim 1, wherein, when it is determined that the two do not coincide with each other, the voltage control unit is controlled to be turned on after being turned off.   3. The USB compatible image according to claim 1, wherein the control unit performs control so that the voltage control unit is turned on after being turned off when a packet response is not transmitted from the connected USB device. 4. Forming equipment.   The control unit includes setting means for setting the power supply voltage to be turned off during the energy saving mode, and controls the voltage control means to be turned off when the power saving voltage is set when the power supply voltage is turned off. The USB-compatible image forming apparatus according to claim 1, wherein the image forming apparatus is a USB-compatible image forming apparatus.   The said setting means can set the operation time of an apparatus, The said control part controls so that the said voltage control means may be turned on within the set operation time, It was described in Claim 5 characterized by the above-mentioned. USB compatible image forming apparatus.

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