摘要:
An image forming apparatus includes an image bearing member for bearing a toner image; a toner image forming portion for forming a toner image on the image bearing member; a rotatable belt member, stretched by a plurality of stretching members, for carrying and conveying a recording material; a transfer member for transferring the toner image from the image bearing member onto the recording material carried on the belt member by pressing the belt member against the image bearing member; a bias applying portion for applying to the transfer member a transfer bias for transferring the toner image from the image bearing member onto the recording material; a push-up member for locally pushing up the belt member from an inner surface side of the belt member, in a direction perpendicular to a recording material conveyance direction, at a downstream-side position of the transfer member with respect to the recording material conveyance direction; and an execution portion for executing an operation in a mode in which the recording material is separated from the belt member by a push-up operation for the belt member by the push-up member. In the mode, the push-up operation of the push-up member is performed, during rotation of the belt member, before the transfer bias is applied to the transfer member.
摘要:
In an image forming apparatus, temporary constant voltages are corrected by using three voltage-current data obtained by applying voltages at three levels to a primary transfer roller to detect currents corresponding to the voltages, respectively. A surface potential of a photosensitive drum is detected by a potential sensor by changing an exposure intensity of an exposure device at three levels in a state in which the temporary constant voltage is applied to the primary transfer roller. A constant voltage during image formation is determined by correcting the temporary constant voltage by using three voltage-current data obtained by detecting currents when surfaces different in potential by light exposure pass through a primary transfer portion.
摘要:
An image forming apparatus includes an image bearing member; a transfer member for transferring a toner image from the image bearing member onto a transfer material at a transfer portion; a control portion for controlling a voltage to be applied to the transfer member; a current detecting portion for detecting a value of a current passing through the transfer portion: a calculating portion for calculating a relationship between values of the voltage and the current which are obtained by applying voltages of different values at different intervals between adjacent images during execution of a continuous image forming mode in which the images are continuously formed on recording materials; a determining portion for determining the voltage value for a target current from the relationship calculated by the calculating portion; and a switching portion for switching the voltage value to the voltage value determined by the determining portion during the execution of the continuous image forming mode.
摘要:
In an image forming apparatus, temporary constant voltages are not by using three voltage-current data obtained by applying voltages at three levels to a primary transfer roller to detect currents corresponding to the voltages, respectively. A surface potential of a photosensitive drum is detected by a potential sensor by changing an exposure intensity of an exposure device at three levels in a state in which the temporary constant voltage is applied to the primary transfer roller. A constant voltage during image formation is determined by correcting the temporary constant voltage by using three voltage-current data obtained by detecting currents when surfaces different in potential by light exposure pass through a primary transfer portion.
摘要:
An image forming apparatus including an image bearing member bearing thereon a toner image charged to a predetermined polarity, a transferring device for electrostatically transferring the toner image borne on the image bearing member to a recording material, first and second cleaning members for electrostatically removing from the image bearing member any toner residual on the image bearing member when the toner image is transferred to the recording material, a first power supply for applying a bias of the same polarity as the predetermined polarity to the first cleaning member, a second power supply for applying a bias of a polarity opposite to the predetermined polarity to the second cleaning member, and a controller for variably controlling the condition of the bias applied to the first cleaning member and the condition of the bias applied to the second cleaning member independently of each other.
摘要:
In the image forming machine of the invention, a two-component type developer has a spherical magnetic powder dispersion type carrier, which has a weight average particle diameter of from 15 to 60 .mu.m. The external additive is present in the form of particles on the toner particle, and comprises inorganic oxide fine particles A having a shape factor SF-1 of from 100 to 130, and non-spherical inorganic oxide fine particles B, having a shape factor SF-1 larger than 150 and particles B having been obtained by combining a plurality of component particles.
摘要:
Provided is an image forming apparatus, including: a first image bearing member; a first transfer member that comes into contact with the intermediate transfer member; a colored toner image forming portion; a second image bearing member; a second transfer member; and a transparent toner image forming portion for forming the transparent toner image wherein the transparent toner image forming portion is provided on an upstream side with respect to the colored toner image forming portion in a movement direction of the intermediate transfer member, and a distance between a most upstream end of the second contact area and the second transfer member in a rotation direction is larger than a distance between a most upstream end of the first contact area and the first transfer member in a rotation direction.
摘要:
An image forming apparatus includes an image bearing member; a transfer member for transferring a toner image from the image bearing member onto a transfer material at a transfer portion; a control portion for controlling a voltage to be applied to the transfer member; a current detecting portion for detecting a value of a current passing through the transfer portion; a calculating portion for calculating a relationship between values of the voltage and the current obtained by applying voltages of different values at different intervals between adjacent images during execution of a continuous image forming mode in which the images are continuously formed on recording materials; a determining portion for determining the voltage value for a target current from the calculated relationship; and a switching portion for switching the voltage value to the voltage value determined by the determining portion during the execution of the continuous image forming mode.
摘要:
Provided is an image forming apparatus, including: a first image bearing member; a first transfer member that comes into contact with the intermediate transfer member; a colored toner image forming portion; a second image bearing member; a second transfer member; and a transparent toner image forming portion for forming the transparent toner image wherein the transparent toner image forming portion is provided on an upstream side with respect to the colored toner image forming portion in a movement direction of the intermediate transfer member, and a distance between a most upstream end of the second contact area and the second transfer member in a rotation direction is larger than a distance between a most upstream end of the first contact area and the first transfer member in a rotation direction.
摘要:
An image forming apparatus includes an image bearing member; toner image forming means for forming a toner image on the image bearing member; a transfer member for transferring the toner image from the image bearing member onto a recording material; an executing portion for executing a first cleaning mode in which the transfer member is cleaned by being supplied with a voltage of an identical polarity to a normal charge polarity of toner during non-image formation and executing a second cleaning mode in which the transfer member is cleaned by being supplied with a voltage of an opposite polarity to the normal charge polarity of the toner during the non-image formation; and a control portion for changing a ratio between a first cleaning mode execution period and a second cleaning mode execution period depending on an operation environment of the image forming apparatus.