Abstract: A method of authenticating a target apparatus by an authentication apparatus that holds a first original key out of a plurality of original keys, and an identifier of the first original key, the target apparatus holding a first value and a plurality of derived keys generated by the plurality of original keys and the first value as inputs to a one-way function, the method includes: the target apparatus selecting a selected key from the plurality of derived keys based on the identifier and generating authentication data based on challenge data and a first generated key based on the selected key; and the authentication apparatus generating an authentication key by the first original key and the first value using the one-way function and generating comparison data based on the challenge data and a second generated key based on the authentication key.

Abstract: An authentication method includes: at a first device, selecting an original key in which a first identifier has a first value and a second identifier has a second value from m original keys and generating an authentication key based on the selected original key and the authentication identifier; at a second device, selecting an authentication key generated from the original key in which the first identifier has the first value and the second identifier has the second value from n authentication keys, generating response data based on challenge data and the authentication key, and notifying the generated response data to the first device; at the first device, generating verification data based on the challenge data and the authentication key, and authenticating the authentication target device by comparing the verification data with the response data.

Abstract: A verification device is configured to supply operation power to a verification target device in order to communicate with the verification target device, and perform verification of the verification target device. The verification device includes: a detection unit configured to detect a value of a current that flows in the verification device due to the operation power being supplied to the verification target device; a determination unit configured to determine whether or not the value of the current is greater than a threshold value; and a verification unit configured to verify authenticity of the verification target device according to whether or not the value of the current is greater than the threshold value.

Abstract: An apparatus that operates with a detachable unit mounted therein, includes: a storage unit configured to store a public key; and a verification unit configured to verify data held by the mounted unit, based on the public key. The data includes attribute information indicating an attribute of the unit, and authentication information generated from target information including the attribute information with a secret key paired with the public key and from which the target information is restorable, and the verification unit is further configured to detect an anomaly in the attribute information or the authentication information included in the data, by determining whether the attribute information included in the target information restored from the authentication information using the public key matches the attribute information included in the data.

Abstract: A processing unit processes an input signal from an external apparatus and includes a first terminal to which a reference voltage is input from the external apparatus, a second terminal to which a first pulse signal having a first frequency is input from the external apparatus, and a control portion to process the input signal. A memory stores data to be transmitted to the external apparatus, and a clock generating unit generates a clock signal having a higher frequency than the first frequency of the first pulse signal. To transmit a data signal to the external apparatus from the processing unit, the control portion switches a load between the first terminal and the second terminal based on the data stored in the memory during a period in which a second pulse signal having a second frequency lower than the first frequency is input from the external apparatus.

Abstract: A verification device is configured to supply operation power to a verification target device in order to communicate with the verification target device, and perform verification of the verification target device. The verification device includes: a detection unit configured to detect a value of a current that flows in the verification device due to the operation power being supplied to the verification target device; a determination unit configured to determine whether or not the value of the current is greater than a threshold value; and a verification unit configured to verify authenticity of the verification target device according to whether or not the value of the current is greater than the threshold value.

Abstract: An apparatus that operates with a detachable unit mounted therein, includes: a storage unit configured to store a public key; and a verification unit configured to verify data held by the mounted unit, based on the public key. The data includes attribute information indicating an attribute of the unit, and authentication information generated from target information including the attribute information with a secret key paired with the public key and from which the target information is restorable, and the verification unit is further configured to detect an anomaly in the attribute information or the authentication information included in the data, by determining whether the attribute information included in the target information restored from the authentication information using the public key matches the attribute information included in the data.

Abstract: A communication apparatus includes a first terminal that receives a reference voltage, a second terminal that receives a pulse signal, and at least one processor to execute instructions. The instructions are executed to generate a clock signal that has a frequency higher than a frequency of the received pulse signal, count a number of pulses of the clock signal and determine a count value counted during a first cycle that is a cycle of the pulse signal to the second terminal, and, during a period of data transmission, increase or decrease an electric current that flows between the communication apparatus and the external apparatus according to a data value of data to be transmitted to the external apparatus. Data is transmitted to the external apparatus at least once during the first cycle, and data switch timing during the first cycle is based on the count value.

Abstract: A target sends ID of a key table. The apparatus receives the ID. The apparatus sends ID of an authentication table to the target. The apparatus sends a challenge corresponding to a pair of the ID of the key table and the ID of the authentication table, to the target. The target obtains, from the key table, a key corresponding to a pair of the ID of the key table and the ID of the authentication table. The target generates a response from the challenge and the key. The target sends the response to the apparatus. The apparatus obtains, from the authentication table, a response corresponding to a pair of the ID of the key table and the ID of the authentication table. The apparatus authenticates the target based on the responses.

Abstract: A method of authenticating a target apparatus by an authentication apparatus that holds a first original key out of a plurality of original keys, and an identifier of the first original key, the target apparatus holding a first value and a plurality of derived keys generated by the plurality of original keys and the first value as inputs to a one-way function, the method includes: the target apparatus selecting a selected key from the plurality of derived keys based on the identifier and generating authentication data based on challenge data and a first generated key based on the selected key; and the authentication apparatus generating an authentication key by the first original key and the first value using the one-way function and generating comparison data based on the challenge data and a second generated key based on the authentication key.

Abstract: A communication apparatus includes: a terminal to which a pulse signal is input from an external apparatus; an acquiring unit configured to acquire a count value during a first cycle that is a cycle of the pulse signal; and a transmitting unit configured to, during a period of data transmission, increase or decrease an electric current that flows between the communication apparatus and the external apparatus according to a data value of data to be transmitted. The transmitting unit is further configured to perform switching on the data to be transmitted at least once during the first cycle, and determine a data switch timing during the first cycle based on the count value.

Abstract: An apparatus that operates with a detachable unit mounted therein, includes: a storage unit configured to store a public key; and a verification unit configured to verify data held by the mounted unit, based on the public key. The data includes attribute information indicating an attribute of the unit, and authentication information generated from target information including the attribute information with a secret key paired with the public key and from which the target information is restorable, and the verification unit is further configured to detect an anomaly in the attribute information or the authentication information included in the data, by determining whether the attribute information included in the target information restored from the authentication information using the public key matches the attribute information included in the data.

Abstract: A verification device is configured to supply operation power to a verification target device in order to communicate with the verification target device, and perform verification of the verification target device. The verification device includes: a detection unit configured to detect a value of a current that flows in the verification device due to the operation power being supplied to the verification target device; a determination unit configured to determine whether or not the value of the current is greater than a threshold value; and a verification unit configured to verify authenticity of the verification target device according to whether or not the value of the current is greater than the threshold value.

Abstract: An image forming apparatus detects a oscillating state of a oscillation system with a oscillation detector and controls oscillation of the oscillation system such that the oscillation system oscillates a reflective member in a balanced steady state by adjusting a drive force of a drive unit with one or more drive control parameter values on the basis of the detection result obtained by the oscillation detector. When the balanced steady state is detected, the drive control parameter values are stored and are used when an exposure unit is reactivated.

Abstract: An image forming apparatus detects a oscillating state of a oscillation system with a oscillation detector and controls oscillation of the oscillation system such that the oscillation system oscillates a reflective member in a balanced steady state by adjusting a drive force of a drive unit with one or more drive control parameter values on the basis of the detection result obtained by the oscillation detector. When the balanced steady state is detected, the drive control parameter values are stored and are used when an exposure unit is reactivated.

Abstract: A heater control circuit performs ON/OFF control of a switching converter for a FET so that an AC line current supplied from a DI terminal becomes approximate to a predetermined value. A current flowing to a heater is stabilized to a predetermined value, and, unless an AC line voltage fluctuates, electric power supplied to the heater is held to a predetermined value. With this contrivance, in an image forming apparatus including a fixing heater (heating heater), a printing speed of the image forming apparatus can be improved to the greatest possible degree under such a condition that a total amount of utilizable electric power is restricted.

Abstract: A heater control circuit performs ON/OFF control of a switching converter for a FET so that an AC line current supplied from a DI terminal becomes approximate to a predetermined value. A current flowing to a heater is stabilized to a predetermined value, and, unless an AC line voltage fluctuates, electric power supplied to the heater is held to a predetermined value. With this contrivance, in an image forming apparatus including a fixing heater (heating heater), a printing speed of the image forming apparatus can be improved to the greatest possible degree under such a condition that a total amount of utilizable electric power is restricted.

Abstract: An object of the present invention is to provide an image forming apparatus that has an image bearing member voltage applying device for applying a voltage having a polarity reverse to that of the toner to the conductive portion of the image bearing member, a charging voltage applying device for applying a voltage to the charging device, a developing voltage applying device for applying a voltage to the developing device, and a transfer voltage applying device for applying only a voltage having a polarity reverse to that of the toner to the transfer device, wherein, the apparatus has a cleaning mode in which, when an image forming is not effected, the voltage is applied to the image bearing member by the image bearing member voltage applying device and the voltage applied to the transfer device from the transfer voltage applying device is turned off or made lower than the voltage applied at the image forming time.

Abstract: A print control apparatus includes an interface controller, a counter, a paper feed controller, and a print controller. The controllers operate in parallel in accordance with a value of the counter and a status of a paper sheet. The number of print instruction or instructions from an external device is counted by the counter, and, if the value counted by the counter is not “0” and if a printing apparatus is ready for feeding a paper sheet, the paper feed controller initiates picking up a paper sheet from a paper feed cassette and conveying it. In turn, the value counted by the counter is decreased by 1. When the print controller detects that the paper sheet is conveyed to a printing position, the paper sheet is printed. The external device can inquire regarding the current value of the counter as well as instruct the decrease or clearance of the value of the counter.

Abstract: An object of the present invention is to provide an image forming apparatus that has an image bearing member voltage applying device for applying a voltage having the same polarity as that of the toner to the conductive portion of the image bearing member, a charging voltage applying device for applying a voltage to the charging device, a developing voltage applying device for applying a voltage to the developing device, and a transfer voltage applying device for applying only a voltage having a polarity reverse to that of the toner to the transfer device, wherein, the apparatus has a cleaning mode in which, when an image forming is not effected, the voltage is applied to the image bearing member by the image bearing member voltage applying device and the voltage applied to the transfer device from the transfer voltage applying device is turned off or made lower than the voltage applied at the image forming time.