1. A polyimide seamless belt for an image forming apparatus, comprising:
polyimide containing a segment derived from aromatic diamine, and a segment derived from aromatic tetracarboxylic acid; and
two types of carbon black, which are high-structure carbon black capable of imparting high conductivity, and acidic carbon black, where the two types of the carbon black are dispersed in the polyimide seamless belt,
wherein the polyimide seamless belt has surface resistivity of 108\u03a9\u25a1 or less.
2. The polyimide seamless belt according to claim 1, wherein a total amount of the two types of the carbon black in the polyimide seamless belt is 8% by weight to 23% by weight.
3. The polyimide seamless belt according to claim 1, wherein the high-structure carbon black contained in the polyimide seamless bel has pH of 6 or higher.
4. The polyimide seamless belt according to claim 1, wherein an amount of the high-structure carbon black in the polyimide seamless belt is 3% by weight to 6% by weight.
5. The polyimide seamless belt according to claim 1, wherein the acidic carbon black contained in the polyimide seamless belt has pH of 4.5 or lower.
6. The polyimide seamless belt according to claim 1, wherein an amount of the acidic carbon black in the polyimide seamless belt is 5% by weight to 17% by weight.
7. A production method of a polyimide seamless belt, comprising:
preparing a polyimide precursor coating liquid, in which polyamic acid that is a polyimide precursor obtained through a reaction between aromatic diamine and aromatic tetracarboxylic acid, high-structure carbon black capable of imparting high conductivity, and acidic carbon black are dissolved or dispersed in an organic solvent;
forming a seamless belt shaped product having a predetermined thickness with the coating liquid; and
drying the seamless belt shaped product, followed by converting the polyamic acid into polyimide, to thereby produce a polyimide seamless belt having surface resistivity of 108\u03a9\u25a1 or less,
wherein the polyimide seamless belt contains the polyimide containing a segment derived from the aromatic diamine, and a segment derived from the aromatic tetracarboxylic acid.
8. An image forming apparatus, comprising:
an electrostatic latent image forming unit configured to form an electrostatic latent image on an image bearer;
a developing unit configured to develop the electrostatic latent image formed on the image bearer with a toner to form a toner image;
a primary transfer unit configured to transfer the toner image from the image bearer onto an intermediate transfer member, where the intermediate transfer member may be a seamless belt;
a secondary transfer unit configured to transfer the toner image from the intermediate transfer member onto a recording medium; and
a fixing unit which is configured to fix the toner image on the recording medium and may contain a seamless belt member,
wherein at least one of the seamless belts used in the image forming apparatus is a polyimide seamless belt which contains:
polyimide containing a segment derived from aromatic diamine, and a segment derived from aromatic tetracarboxylic acid; and
two types of carbon black, which are high-structure carbon black capable of imparting high conductivity, and acidic carbon black, where the two types of the carbon black are dispersed in the polyimide seamless belt,
wherein the polyimide seamless belt has surface resistivity of 108\u03a9\u25a1 or less.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An apparatus for identifying an access network, the apparatus comprising:
a packet capturing unit configured to capture a plurality of packets transmitted or received by a server;
a flow classifying unit configured to classify each of the captured packets into individual flows with reference to at least one of an origination address, a destination address, and a port number;
a round trip time (RTT) calculating unit configured to calculate RTT values from the packets classified into a flow of the individual flows;
an access network determining unit configured to determine that an origination address included in a packet classified into the flow is an address accessing the server through a first communication network when the RTT calculated values exceed a reference value; and
a storage unit configured to store the address accessing the server through the first communication network.
2. The apparatus of claim 1, wherein the reference value is set to a value in a range of 25 to 60 milliseconds (ms).
3. The apparatus of claim 1, wherein the first communication network comprises a 3G mobile communication network.
4. The apparatus of claim 1, wherein the flow is a Transmission Control Protocol (TCP) flow.
5. The apparatus of claim 1, wherein the RTT values comprise a time difference between a transmission time of a \u2018SYN+ACK packet\u2019 transmitted from the server and a reception time of a corresponding \u2018ACK packet\u2019.
6. The apparatus of claim 1, wherein the access network determining unit compares a first count comprising a number of cases in which the calculated RTT values exceed the reference value with a second count comprising a number of cases in which the calculated RTT values do not exceed the reference value, and determines that the origination address is a terminal address accessing through the first communication network when the first count is greater than the second count, with respect to a plurality of flows received from the origination address.
7. The apparatus of claim 1, wherein the access network determining unit excludes a terminal address from a list of the first communication network when a sum of a number of cases in which the calculated RTT values exceed the reference value and a number of cases in which the calculated RTT values do not exceed the reference value is a preset number, with respect to a plurality of flows received from the terminal address.
8. The apparatus of claim 5, further comprising a user agent (UA) inspecting unit configured to inspect a UA item in header information of a packet captured through the flow and to exclude the packet’s origination address from a list of the first communication network when the UA item is not a system configured to use the first communication network.
9. The apparatus of claim 8, wherein the packet captured through the flow is an \u2018HTTP request packet\u2019 transmitted to the server after transmission of the \u2018ACK packet\u2019.
10. The apparatus of claim 1, further comprising an address converting unit configured to convert the origination address of a terminal on the respective flows into a network address to allow the access network determining unit to determine the access network with respect to the network address.
11. The apparatus of claim 10, wherein the origination address of the terminal comprises an Internet Protocol (IP) address of 32 bits, and the network address comprises a range of bits selected from upper 24 to 31 bits in the 32 bit IP address.
12. The apparatus of claim 1, further comprising an IP determining unit configured to determine whether the origination address of a terminal is an address received from overseas and to exclude the origination address of the terminal from a list of the first communication network.
13. The apparatus of claim 1, further comprising a network operator classifying unit configured to determine a network operator for the origination address of a terminal with reference to a network operator IP list database.
14. A method for identifying an access network, the method comprising:
capturing with a packet capturing unit a plurality of packets transmitted or received by a server;
classifying with a flow classifying unit each of the captured packets into individual flows with reference to at least one of an origination address, a destination address, and a port number;
calculating with a round trip time (RTT) calculating unit, RTT values from the packets classified into a flow of the individual flows;
determining with an access network determining unit that an origination address included in a packet classified into the flow is an address accessing the server through a first communication network when the RTT calculated values exceed a reference value; and
storing with a storage unit the address accessing the server through the first communication network.
15. The method of claim 14, wherein the reference value is set to a value in a range of 25 to 60 milliseconds (ms).
16. The method of claim 14, wherein the RTT values comprise a time difference between a transmission time of a \u2018SYN+ACK packet\u2019 transmitted from the server and a reception time of a corresponding \u2018ACK packet\u2019.
17. The method of claim 14, wherein the access network determining unit compares a first count comprising a number of cases in which the calculated RTT values exceed the reference value with a second count comprising a number of cases in which the calculated RTT values do not exceed the reference value, and determines that the origination address is a terminal address accessing through the first communication network when the first count is greater than the second count, with respect to a plurality of flows received from the origination address.
18. The method of claim 14, wherein the access network determining unit excludes a terminal address from a list of the first communication network when a sum of a number of cases in which the calculated RTT values exceed the reference value and a number of cases in which the calculated RTT values do not exceed the reference value is a preset number, with respect to a plurality of flows received from the terminal address.
19. The method of claim 16, further comprising inspecting with a UA inspecting unit a UA item in header information of a packet captured through the flow and to exclude the packet’s origination address from a list of the first communication network when the UA item is not a system configured to use the first communication network.
20. One or more non-transitory computer-readable storage media having stored thereon a computer program that, when executed by one or more processors, causes the one or more processors to perform acts comprising:
capturing with a packet capturing unit a plurality of packets transmitted or received by a server;
classifying with a flow classifying unit each of the captured packets into individual flows with reference to at least one of an origination address, a destination address, and a port number;
calculating with a round trip time (RTT) calculating unit, RTT values from the packets classified into a flow of the individual flows;
determining with an access network determining unit that an origination address included in a packet classified into the flow is an address accessing the server through a first communication network when the RTT calculated values exceed a reference value; and
storing with a storage unit the address accessing the server through the first communication network.