1. A circuit board connected to a connector, the connector comprising a connection port arranged to receive an object to be connected and a plurality of contact portions located at upper and lower positions of the connection port, wherein any of the contact portions at one of the upper and lower positions and any of the contact portions at the other position face each other in a vertical direction, and each contact portion is connected electrically to the opposite contact portion, the circuit board comprising:
a base substrate;
a first wiring layer located on a first principal surface of the base substrate; and
a second wiring layer located on a second principal surface of the base substrate; wherein
first terminals connected to the first wiring layer are provided on the first principal surface, and second terminals connected to the second wiring layer are provided on the second principal surface, and
the first terminals and the second terminals come into contact with any of the contact portions and are arranged so as not to overlap each other in the vertical direction.
2. The circuit board according to claim 1, wherein dummy terminals that are insulated electrically from the first wiring layer and the second wiring layer are provided on both principal surfaces of the base substrate, and the dummy terminals are located in a region that is on the opposite side of the base substrate relative to a region where the first terminals or the second terminals are provided.
3. The circuit board according to claim 1, wherein the base substrate is flexible, and the circuit board is a flexible printed circuit board.
4. The circuit board according to claim 1, wherein electronic components are mounted on the first principal surface so as to be connected electrically to the first wiring layer, and different electronic components from those electronic components are mounted on the second principal surface so as to be connected electrically to the second wiring layer.
5. A connection structure comprising:
a connector; and
a circuit board, the connector and the circuit board being connected to define the connection structure; wherein
the connector includes a connection port arranged to receive the circuit board and a plurality of contact portions located at upper and lower positions of the connection port;
any of the contact portions at one of the upper and lower positions and any of the contact portions at the other position face each other in a vertical direction;
each contact portion is connected electrically to the opposite contact portion;
the circuit board includes a base substrate, a first wiring layer located on a first principal surface of the base substrate, and a second wiring layer located on a second principal surface of the base substrate;
first terminals connected to the first wiring layer are provided on the first principal surface, and second terminals connected to the second wiring layer are provided on the second principal surface, and
the first terminals and the second terminals come into contact with any of the contact portions and are arranged so as not to overlap each other in the vertical direction.
6. The connection structure according to claim 5, wherein dummy terminals that are insulated electrically from the first wiring layer and the second wiring layer are provided on both principal surfaces of the base substrate, and the dummy terminals are located in a region that is on the opposite side of the base substrate relative to a region where the first terminals or the second terminals are provided.
7. The connection structure according to claim 5, wherein the base substrate is flexible, and the circuit board is a flexible printed circuit board.
8. The connection structure according to claim 5, wherein electronic components are mounted on the first principal surface so as to be connected electrically to the first wiring layer, and different electronic components from those electronic components are mounted on the second principal surface so as to be connected electrically to the second wiring layer.
9. An apparatus comprising the connection structure according to claim 5.
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. A developing device for applying powder to a latent image carrying member to develop latent images on the latent image carrying member, comprising:
a transport member disposed in opposition to the latent image carrying member, and having a plurality of transport electrodes for generating electric fields to transport powder;
voltage supply means for applying n phase (where n is a positive integer equal to or greater than 2) voltage to the transport electrodes; and
transport member surface potential determination means for determining the surface potential of the transport member, wherein
the voltage supply means applies the n phase voltage to the transport electrodes so that the surface potential on the transport member is between the potential of the image portions and the potential of the non-image portions of the latent image carrying member.
2. The developing device as claimed in claim 1, wherein when latent image forming and developing are repeated to successively develop powder in different colors on the same latent image carrying member, the voltage supply means applies the n phase voltage to the transport electrodes so that the surface potential on the transport member is between the potential of the image portions and the potential of the non-image portions of the latent image carrying member in respect of the powder of each color.
3. The developing device as claimed in claim 1, wherein when developing the powder for the second and subsequent colors, the voltage supply means applies the n phase voltage to the transport electrodes so that the surface potential on the transport member is between the potential of the image portions that has been reduced by the charge of the previously developed powder and the potential of the non-image portions of the latent image carrying member.
4. The developing device as claimed in claim 1, wherein when developing the powder for the second and subsequent colors, the voltage supply means applies the n phase voltage to the transport electrodes so that the surface potential on the transport member is between the potential of the image portions, for which the charge on the previously developed powder has been increased by charging that is carried out prior to writing the latent image, and the potential of the non-image portions, of the latent image carrying member.
5. The developing device as claimed in claim 1, wherein when developing the powder for the second and subsequent colors, the voltage supply means applies the n phase voltage to the transport electrodes so that the surface potential on the transport member is between the potential of the image portions that has been reduced by the charge of the previously developed powder and the charge on the powder that has been increased by charging that is carried out prior to writing the latent image, and the potential of the non-image portions of the latent image carrying member.
6. The developing device as claimed in claim 1, wherein the electric field that moves the powder is a progressive wave electric field.
7. The developing device as claimed in claim 1, wherein the wave form of the voltage applied to the electrodes of the transport member is a wave form obtained by superimposing a direct current bias onto a pulse voltage.
8. The developing device as claimed in claim 1, wherein surface potential V on the transport member, when the surface potential V on the mth time (where m is a positive integer) in an order that powder is applied to the latent image carrying member is Vm, satisfies Vm>Vm+1.
9. A process cartridge which has at least a developing device for developing latent images on a latent image carrying member by applying powder to the latent image carrying member, and which can be freely inserted into and removed from a main body of an image forming apparatus, the process cartridge comprising:
a transport member disposed in opposition to the latent image carrying member and having a plurality of transport electrodes that generate electric fields to transport powder;
voltage supply means for applying n phase (where n is a positive integer equal to or greater than 2) voltage to the transport electrodes; and
transport member surface potential determination means for determining the surface potential of the transport member, wherein
the voltage supply means applies the n phase voltage to the transport electrodes so that the surface potential on the transport member is between the potential of the image portions and the potential of the non-image portions of the latent image carrying member.
10. An image forming apparatus comprising either a developing device that applies powder to a latent image carrying member to develop latent images on the latent image carrying member, or a process cartridge, wherein
the developing device comprises:
a transport member disposed in opposition to the latent image carrying member and having a plurality of transport electrodes that generate electric fields to transport powder;
voltage supply means for applying n phase (where n is a positive integer equal to or greater than 2) voltage to the transport electrodes; and
transport member surface potential determination means for detetermining the surface potential of the transport member, wherein
the voltage supply means applies the n phase voltage to the transport electrodes so that the surface potential on the transport member is between the potential of the image portions and the potential of the non-image portions of the latent image carrying member, and
the process cartridge comprises at least the developing device, and can be freely inserted into and removed from the main body of the image forming apparatus.
11. The image forming apparatus as claimed in claim 10, further comprising potential control means for controlling the surface potential on the transport member of the developing device so that the surface potential is a value between the potential of the image portions and the potential of the non-image portions of the latent image carrying member.
12. The image forming apparatus as claimed in claim 10, wherein the transport voltage applied to the transport member of the developing device is a wave form in which a pulse voltage and a direct current bias are superimposed, and the transport voltage is controlled by adjusting the value of the direct current bias.
13. A color image forming apparatus which comprises a plurality of process cartridges including at least a developing device for developing latent images on a latent image carrying member by applying powder to the latent image carrying member, and which can be freely inserted into and removed from the main body of the image forming apparatus, wherein
the developing device comprises:
a transport member disposed in opposition to the latent image carrying member and having a plurality of transport electrodes that generate electric fields to transport powder;
voltage supply means for applying n phase (where n is a positive integer equal to or greater than 2) voltage to the transport electrodes; and
transport member surface potential determination means for determining the surface potential of the transport member, wherein
the voltage supply means applies the n phase voltage to the transport electrodes so that the surface potential on the transport member is between the potential of the image portions and the potential of the non-image portions of the latent image carrying member.