Image forming apparatus
First Claim
1. An image forming method in an image forming apparatus, the apparatus including a first, second, third and fourth image forming units configured to form yellow, magenta, cyan, and black toner image and a transfer member, the first, second, third and fourth image forming units respectively having a photoreceptor and a developing unit which develops electrostatic image formed on the corresponding photoreceptor and collects toner remaining on the corresponding photoreceptor, and the transfer member which transfers the respective toner image formed on the respective photoreceptor of the first, second, third and fourth image forming units onto an image bearing member overlappingly, the method comprising:
- developing the electrostatic image formed on the corresponding photoreceptor in the fourth image forming unit with a larger developed amount of toner than the developed amount of toner for developing the electrostatic image formed on the corresponding photoreceptors in the first to third image forming units, the toner configured to satisfy conditions of Pa≧
Pb≧
Pc≧
Pd and Pa>
Pd, where Pa, Pb, Pc, and Pd indicate volume-based average particle diameters of toners to be developed on the photoreceptor in the order of development;
moving the image hearing member to the first, second, third and fourth image forming units in order; and
transferring the yellow, magenta, cyan and black toner image formed on the respective photoreceptor onto the image bearing member overlappingly.
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Abstract
There is provided a photoreceptor cleanerless image forming apparatus capable of decreasing color mixture or an exposure error due to reverse transfer toner an untransferred toner. An image forming apparatus 100 according to the present invention comprises four image forming units 100a, 100b, 100c, and 100d configured to be photoreceptor cleanerless in a 4-drum tandem manner. Each image forming unit includes a photoreceptor 103a, 103b, 103c, or 103d, a charger 105a, 105b, 105c, or 105d, an exposure apparatus 106a, 106b, 106c, or 106d, and a developing apparatus 109a, 109b, 109c, or 109d. When exposure intensities Iy, Ic, Im, and Ik are assumed for exposure sources of the exposure apparatuses in the image forming units which form yellow, magenta, cyan, and black images, respectively, the exposure intensities are configured to satisfy conditions of Ik≧Ic≧Im≧Iy and Ik>Iy. This decreases an exposure error (image hysteresis) in an image formed on paper.
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Citations
16 Claims
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1. An image forming method in an image forming apparatus, the apparatus including a first, second, third and fourth image forming units configured to form yellow, magenta, cyan, and black toner image and a transfer member, the first, second, third and fourth image forming units respectively having a photoreceptor and a developing unit which develops electrostatic image formed on the corresponding photoreceptor and collects toner remaining on the corresponding photoreceptor, and the transfer member which transfers the respective toner image formed on the respective photoreceptor of the first, second, third and fourth image forming units onto an image bearing member overlappingly, the method comprising:
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developing the electrostatic image formed on the corresponding photoreceptor in the fourth image forming unit with a larger developed amount of toner than the developed amount of toner for developing the electrostatic image formed on the corresponding photoreceptors in the first to third image forming units, the toner configured to satisfy conditions of Pa≧
Pb≧
Pc≧
Pd and Pa>
Pd, where Pa, Pb, Pc, and Pd indicate volume-based average particle diameters of toners to be developed on the photoreceptor in the order of development;moving the image hearing member to the first, second, third and fourth image forming units in order; and transferring the yellow, magenta, cyan and black toner image formed on the respective photoreceptor onto the image bearing member overlappingly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An image forming method in an image forming apparatus, the apparatus including a first, second, third and fourth image forming units configured to form yellow, magenta, cyan, and black toner image and a transfer member, the first, second, third and fourth image forming units respectively having a photoreceptor and a developing unit which develops electrostatic image formed on the corresponding photoreceptor and collects toner remaining on the corresponding photoreceptor, and the transfer member which transfers the respective toner image formed on the respective photoreceptor of the first, second, third and fourth image forming units onto an image bearing member overlappingly, the method comprising:
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developing the electrostatic image formed on the corresponding photoreceptor in the fourth image forming unit with a larger developed amount of toner than the developed amount of toner for developing the electrostatic image formed on the corresponding photoreceptors in the first to third image forming units, the toner configured to satisfy conditions of Qa≦
Qb≦
Qc≦
Qd and Qa<
Qd, where Qa, Qb, Qc, and Qd indicate weight-based average charged amounts of toners to be transferred to the image bearing member in the order of transferring and Qa, Qb, Qc and Qd correspond to the weight-based average charged amounts of yellow, magenta, cyan and black toner, respectively;moving the image bearing member to the first, second, third and fourth image forming units in order; and transferring the yellow, magenta, cyan and black toner image formed on the respective photoreceptor onto the image bearing member overlappingly. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification