Back to results
US 5,126,913 AGranted
Charging device with contactable charging means and an image forming apparatus having the charging means and a detachable process unit
AssigneeCanon Kabushiki Kaisha
InventorsJunji Araya, Masanobu Saito, Hiroki Kisu, Yohji Tomoyuki, Shunji Nakamura, Noribumi Koitabashi, Hiroyuki Adachi
Life of this patent
Estimating the term…
Abstract
A charging device for charging a moving member to be charged includes charging device for being contacted to the member to be charged to charge the member; a voltage source for applying a vibratory voltage to the charging device; wherein the charging device includes a first layer contactable to the member to be charged, a second layer adjacent thereto wherein the first layer is a dielectric layer having a volume resistivity larger than that of the second layer.
Claims78
A charging device for charging a moving member to be charged, comprising:
- charging means for being contacted to the member to be charged to charge the member;
- means for applying a voltage to said charging means, wherein the voltage has a peak-to-peak voltage which is not less than twice of an absolute value of a charge starting voltage relative to the member;
- wherein said charging means includes a first layer contactable to the member to be charged, a second layer adjacent thereto wherein the first layer is a dielectric layer having a volume resistivity larger than that of the second layer.
A charging device for charging a moving member to be charged, comprising:
- charging means for being contacted to the member to be charged to charge the member;
- means for applying a vibratory voltage to the charging means;
- wherein said charging means includes a surface dielectric layer at a contact portion with the member, and the impedance component of the electrostatic capacity of said charging means is smaller than the impedance component of the resistance thereof.
A charging device for charging a moving member to be charged, comprising:
- charging means for being contacted to the member to be charged to charge the member;
- means for applying a voltage to said charging
- wherein said charging means includes a high resistance layer at a portion where it is contacted to the member to be charged, and the following is satisfied:
- .rho.l>E.sup.2 .times.(0.1.times.10.sup.-3).sup.2 /P (ohm.m.sup.2)
- where .rho. is a volume resistivity (ohm.m) of the high resistance layer, l (m) is a thickness of the high resistance layer, E is the voltage (V) applied by said voltage applying means, P is a capacity (W) of a voltage source of said voltage applying means.
2 more elements
A charging device for charging a moving member to be charged, comprising:
- charging means for being contacted to the member to be charged to charge the member;
- means for applying a voltage to said charging means,
- wherein said charging means includes a high resistance layer at a portion where it is contacted to the member to be charged, and the following is satisfied:
- .rho.l>E.sup.2 .times.(0.1.times.10.sup.-3).sup.2 /P(ohm.m.sup.2)
- where in .rho. is a volume resistivity (ohm.m) of the high resistance layer, l (m) is a thickness of the high resistance layer, E is the voltage (V) applied by said voltage applying means, P is a capacity (W) of the voltage source of said voltage applying means;
- wherein R2 of said charging means at a nip between said charging mean and the member to be charged and an electrostatic capacitance C2 of said charging means at this nip satisfy:
- ##EQU11## where E1-V.sub.2(n=.infin.) is a saturated voltage of said charging means, E1 is a voltage (V) applied to said charging means, C1 is a electrostatic capacity of the member to be charged at the nip, R1 is a resistance of the member to be charged at the nip,
- t.sub.1 =(a width of the nip)/(a peripheral speed of said charging means)
- t.sub.2 =(a peripheral length of said charging means)/(a peripheral speed of said charging means)
- wherein E2 is a charge starting voltage of the member to be charged.
7 more elements
An image forming apparatus, comprising:
- a moving image bearing member;
- charging means for being contacted to he image bearing member to charge the image bearing member;
- means for applying a voltage to said charging means, wherein the voltage has a peak-to-peak voltage which is not less than twice of an absolute value of a charge starting voltage relative to the member;
- wherein said charging means includes a first layer contactable to the member to be charged, a second layer adjacent thereto, wherein the first layer is a dielectric layer having a volume resistivity larger than that of the second layer.
1 more element
An image forming apparatus, comprising:
- a movable image bearing member;
- charging means for being contacted to said image bearing member to charge the image bearing member;
- means for applying a vibratory voltage to the charging means;
- wherein said charging means includes a surface dielectric layer at a contact portion with the image bearing member, and the impedance component of the electrostatic capacity of said charging means is smaller than the impedance component of the resistance thereof.
1 more element
An image forming apparatus, comprising:
- a movable image bearing member;
- charging means for being contacted to said image bearing member to charge the image bearing member;
- means for applying a voltage to said charging means;
- wherein said charging means includes high resistance layer at a portion where it is contacted to the image bearing member, and the following is satisfied:
- .rho.l>E.sup.2 .times.(0.1.times.10.sup.-3).sup.2 /P(ohm.m.sup.2)
- where in .rho. is a volume resistivity (ohm.m) of the high resistance layer, l (m) is a thickness of the high resistance layer, E is the voltage (V) applied by said voltage applying means, P is a capacity (W) of the voltage source of said voltage applying means.
3 more elements
A process unit detachably mountable to an image forming apparatus, comprising:
- an image bearing member;
- charging means for being contacted to the image bearing member to charge the image bearing member, wherein a charging voltage has a peak-to-peak voltage which is not less than twice of an absolute value of a charge starting voltage relative to the member;
- wherein said charging means includes a first layer contactable to the image bearing member, a second layer adjacent thereto wherein the first layer is a dielectric layer having a volume resistivity larger than that of the second layer.
A process unit detachably mountable to an image forming apparatus, comprising:
- an image bearing member;
- charging means for being contacted to the image bearing member to charge the image bearing member, said charging means being supplied with a vibratory voltage;
- wherein said charging means includes a surface dielectric layer at a contact portion with the image bearing member, and the impedance components of the electrostatic capacity of said charging means is smaller than the impedance component of the resistance thereof.
A process unit detachably mountable to an image forming apparatus, comprising:
- an image bearing member;
- charging means for being contacted to the image bearing member to charge the image bearing member, said charging means being supplied with a voltage;
- wherein said charging means include a high resistance layer at a portion wherein it is contacted to the image bearing member, and the following is satisfied:
- .rho.l>E.sup.2 .times.(0.1.times.10.sup.-3).sup.2 /P(ohm.m.sup.2)
- where in .rho. is a volume resistivity (ohm.m) of the high resistance layer, l (m) is a thickness of the high resistance layer, E is the voltage (V) applied by said charging means, P is a capacity (W) of a voltage source of said voltage applying the voltage.
2 more elements
Dependencies are inferred from the claim text.