【特許請求の範囲】
【請求項１】 像担持体表面に接触配置された帯電部材により前記像担持体表面を一様に帯電する帯電手段と、帯電後の前記像担持体表面を画像情報に応じて露光して静電潜像を形成する露光手段と、前記静電潜像にトナーを付着させてトナー像として現像する現像手段と、前記像担持体上のトナー像を転写材上に転写する転写手段とを備え、前記像担持体上の残留トナーを前記帯電部材を通過させて前記現像手段で回収する画像形成装置において、
前記帯電部材に帯電バイアスを印加し、前記帯電部材と前記像担持体との間の放電により前記像担持体表面を帯電する帯電バイアス電源と、
前記帯電バイアス電源を制御する制御手段と、を備え、
前記制御手段は、画像形成動作が途中で停止された後の再起動時に、前記帯電バイアス電源により前記帯電部材に前記トナーの帯電極性と同極性でかつ放電閾値以下のバイアスを所定時間印加した後、前記トナーの帯電極性と同極性でかつ放電閾値以上のバイアスを印加する、
ことを特徴とする画像形成装置。
【請求項２】 前記像担持体上のトナー像が前記転写材に転写される位置を転写位置、また、前記像担持体表面が前記帯電部材によって帯電される位置を帯電位置としたときに、
前記像担持体表面の移動方向に沿っての、前記転写位置の下流側でかつ前記帯電位置の上流側に、前記像担持体上のトナーを散乱させるためのトナーちらし部材が配設されている、
ことを特徴とする請求項１に記載の画像形成装置。
【請求項３】 前記帯電部材は、円筒状の帯電ローラであり、最表面における動摩擦係数が０．０１〜０．４である、
ことを特徴とする請求項１または２に記載の画像形成装置。
【請求項４】 前記トナーは、少なくとも結着樹脂、着色剤、ワックス成分を含有する静電潜像現像用のトナーであり、透過電子顕微鏡を用いたトナー粒子の断層面観察において、前記ワックス成分が結着樹脂と相溶しない状態でかつ実質的に球状および／または紡錘形の島状で前記トナー粒子中に含有されている、
ことを特徴とする請求項１、２、または３に記載の画像形成装置。
【請求項５】 画像解析装置で測定した前記トナーの形状係数ＳＦ１が１００〜１６０であり、形状係数ＳＦ２が１００〜１４０である、
ことを特徴とする請求項１、２、３、または４に記載の画像形成装置。
[Claims]
1. A charging means that uniformly charges the surface of the image carrier by a charging member contact-arranged on the surface of the image carrier, and the surface of the image carrier after charging is exposed and static electricity according to image information. An exposure means for forming an electro-latent image, a developing means for adhering toner to the electrostatic latent image to develop it as a toner image, and a transfer means for transferring the toner image on the image carrier onto a transfer material are provided. In an image forming apparatus, the residual toner on the image carrier is passed through the charging member and recovered by the developing means.
A charging bias power source that applies a charging bias to the charging member and charges the surface of the image carrier by discharging between the charging member and the image carrier.
A control means for controlling the charge bias power supply is provided.
The control means applies a bias having the same polarity as the charging polarity of the toner and equal to or less than the discharge threshold value to the charging member by the charging bias power supply at the time of restarting after the image forming operation is stopped in the middle for a predetermined time. , Apply a bias that has the same polarity as the charging polarity of the toner and is equal to or greater than the discharge threshold value.
An image forming apparatus characterized in that.
2. The position where the toner image on the image carrier is transferred to the transfer material is defined as the transfer position, and the position where the surface of the image carrier is charged by the charging member is defined as the charging position.
A toner leaflet member for scattering toner on the image carrier is arranged on the downstream side of the transfer position and on the upstream side of the charged position along the moving direction of the surface of the image carrier. ,
The image forming apparatus according to claim 1.
3. The charging member is a cylindrical charging roller having a coefficient of dynamic friction on the outermost surface of 0.01 to 0.4.
The image forming apparatus according to claim 1 or 2.
4. The toner is a toner for electrostatic latent image development that contains at least a binder resin, a colorant, and a wax component, and the wax component is observed in a tomographic plane of toner particles using a transmission electron microscope. Is contained in the toner particles in a substantially spherical and / or spindle-shaped island shape in a state of being incompatible with the binder resin.
The image forming apparatus according to claim 1, 2, or 3.
5. The shape coefficient SF1 of the toner measured by an image analyzer is 100 to 160, and the shape coefficient SF2 is 100 to 140.
The image forming apparatus according to claim 1, 2, 3, or 4.
ＶＤ＜ＶＤＣ＜ＶＬ＜０＜ＶＴ
ただし、ＶＤ ：感光ドラム表面の帯電電位、
ＶＤＣ：現像器のバイアス電位、
ＶＬ ：感光ドラム表面のうちの露光器で露光された部分の電位、
０ ：零電位、
ＶＴ ：転写除電後の感光ドラム表面電位、
現像は、「ＶＤＣ〜ＶＬ」の電位差によって行われ、転写は、「ＶＬ〜ＶＴ」の電位差によって行われる。
V D <V DC < VL <0 < VT
However, V D : Charging potential on the surface of the photosensitive drum,
VDC : Bias potential of the developer,
VL : The potential of the part of the surface of the photosensitive drum exposed by the exposure device,
0 : Zero potential ,
V T: surface potential of the photosensitive drum after the transfer neutralization,
Development is performed by a potential difference "V DC ~V L", transfer is done by the potential difference "V L ~V T".
請求項２に係る本発明は、請求項１の画像形成装置において、前記像担持体上のトナー像が前記転写材に転写される位置を転写位置、また、前記像担持体表面が前記帯電部材によって帯電される位置を帯電位置としたときに、前記像担持体表面の移動方向に沿っての、前記転写位置の下流側でかつ前記帯電位置の上流側に、前記像担持体上のトナーを散乱させるためのトナーちらし部材が配設されている、ことを特徴とする。
According to the second aspect of the present invention, in the image forming apparatus of the first aspect, the position where the toner image on the image carrier is transferred to the transfer material is the transfer position, and the surface of the image carrier is the charging member. When the position charged by is set as the charging position, the toner on the image carrier is placed on the downstream side of the transfer position and on the upstream side of the charging position along the moving direction of the surface of the image carrier. It is characterized in that a toner fluttering member for scattering is arranged.
供給ローラ９によって現像ローラ８上に塗布されたトナーは、次に規制ブレード１０によりトナー量の規制および摩擦によるトリボ付与が行われる。規制ブレード１０は、ステンレス製の薄板（厚さ約０．１mm）の先端部から約２mmの位置を現像ローラ８と反対方向に折り曲げたものであり、この折曲げ部が現像ローラ８に若干食い込む状態で接触するように配設されている。
The toner applied on the developing roller 8 by the supply roller 9 is then regulated by the regulating blade 10 and trivoed by friction. The regulation blade 10 is formed by bending a thin stainless steel plate (thickness of about 0.1 mm) about 2 mm from the tip in the direction opposite to the developing roller 8, and this bent portion slightly bites into the developing roller 8. It is arranged so as to come into contact with each other in a state.
【０１３４】
【発明の効果】
以上述べたように、像担持体に接触配置された帯電部材を用いる現像同時クリーニング方式の画像形成装置において、ジャム時のジャム処理後の再起動時に、帯電部材に、トナーの帯電極性と同極性でかつ放電閾値以下のバイアスを所定時間印加した後、トナーの帯電極性と同極性でかつ放電閾値以上のバイアスを印加することで、像担持体を介して帯電部材に多量の未転写トナーが突入した場合でも、未転写トナーに対して帯電部材側から像担持体側へ付勢するバイアスを印加することができるので、像担持体の帯電不良及び帯電部材の汚れを有効に防止することができる。
[0134]
【Effect of the invention】
As described above, in the image forming apparatus of the simultaneous development cleaning method using the charging member arranged in contact with the image carrier, the charging member has the same polarity as the charging polarity of the toner at the time of restarting after the jam treatment at the time of jamming. After applying a bias below the discharge threshold for a predetermined time, a large amount of untransferred toner rushes into the charged member via the image carrier by applying a bias with the same polarity as the charging polarity of the toner and above the discharge threshold. Even in this case, since the bias that urges the untransferred toner from the charged member side to the image carrier side can be applied, it is possible to effectively prevent the image carrier from being poorly charged and the charged member from being contaminated.