JPS5917571A - Electrostatically charging device for separation - Google Patents

Abstract

PURPOSE:To separate a transferring material stably even when the peripheral speed of a photoreceptor varies by varying the amount of electrostatic charge for separation according to the peripheral speed of an image holder. CONSTITUTION:A gear 12 coaxial with the photoreceptor 1 rotates a saw-tooth disk 14 through a driving gear 13. A photodetector 15 engages the disk 14 to detect the rotation of the photoreceptor 1, and the detection result is monitored by a CPU 16. Therefore, when the peripheral speed of the photoreceptor is varied in life-size mode, that is detected by the CPU to output the voltage and current of an electrostatic charger 8 for separation to an output transformer HVT 17. When the peripheral speed is reduced in reduction-size mode, this processing is performed and such destaticization that retransfer to the transferring material is caused and charges on the transferring material are neutralized sufficiently is performed to separate the transferring material. When the peripheral speed is reduced for compensating deficiency in exposure in enlarged-size mode, a signal for lowering the voltage is sent similarly from the CPU to the charger 8.

Description

【発明の詳細な説明】 本発明はコロナ放電によ）転写材を感光体や絶縁体等の
像保持体面より静電的に剥離する分離帯電装置に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a separation/charging device that electrostatically separates a transfer material (by corona discharge) from the surface of an image carrier such as a photoreceptor or an insulator.

分離帯電器を有する電子写真装置の従来例の概略図を第
１図に示す。まず、感光体１は帯電器２によυ一様に帯
電された後、一連の光学ランプ６、ミラー５ａ〜５ｄ、
レンズｌによりｉ稿４からの光像が霧光され、表面に静
電潜像が形成される。A schematic diagram of a conventional electrophotographic apparatus having a separation charger is shown in FIG. First, the photoreceptor 1 is uniformly charged by the charger 2, and then a series of optical lamps 6, mirrors 5a to 5d,
The light image from the i-paper 4 is fogged by the lens l, and an electrostatic latent image is formed on the surface.

この潜像は現像器７によ如トナー像として顕画化される
。感光体１の周回運動に同期して転写材Ｐが感光体面に
送シ込まれ、転写帯電器８によ）転写材Ｐ上にトナー像
を転写する。次いで転写材Ｐは分離帯電器９によυ感光
体面から静電的に分離され、定着器１０を経てトナー像
が完全に転写材Ｐ上に定着される。This latent image is developed as a toner image by the developing device 7. A transfer material P is fed onto the photoreceptor surface in synchronization with the rotational movement of the photoreceptor 1, and a toner image is transferred onto the transfer material P by a transfer charger 8). Next, the transfer material P is electrostatically separated from the photoreceptor surface by a separation charger 9, and the toner image is completely fixed onto the transfer material P via a fixing device 10.

一方、感光体１上の残余のトナーはクリーナー１１によ
り除去され、次の複写プロセスに備えられる。On the other hand, the remaining toner on the photoreceptor 1 is removed by a cleaner 11 and is prepared for the next copying process.

上記の内、光学系に属するレンズ６の位置を変えること
により、感光体上の結像を原稿像に対して拡大及び縮小
することが可能である。さてこの様な変倍機能を持った
電子写真装置では、帯電量あるいは露光量の過不足を無
（するため変倍時に、感光体の周回速度を変え、その各
賞を適正な値とする様な工夫がなされている。しかるに
、この様な装置においては、従来、転写・分離帯電器の
出力が変倍、非変倍時にかかわらず一定であったため、
定な画質と分離を余儀なくされていた。また、転写帯電
量を可変とする装置においても分離除電量が一定であっ
たため、やはシネ安定な分離に終始せざ、るな得なかっ
た。Among the above, by changing the position of the lens 6 belonging to the optical system, it is possible to enlarge or reduce the image formed on the photoreceptor with respect to the original image. Now, in an electrophotographic device having such a variable magnification function, in order to avoid excess or deficiency in the amount of charge or exposure, the rotation speed of the photoreceptor is changed when changing the magnification, and each award is set to an appropriate value. However, in such devices, the output of the transfer/separation charger was conventionally constant regardless of whether the magnification was variable or not.
They were forced to maintain stable image quality and separation. Furthermore, even in an apparatus in which the transfer charge amount is variable, the separation charge removal amount is constant, so it is inevitable to achieve cine-stable separation from beginning to end.

即ち、縮小時、光学系の移動速度を抑えて機械的なブレ
を軽減するため、感光体の回転速度即ち査 プロセス・スピードを非変倍時（涙倍時）の速度。In other words, in order to suppress the moving speed of the optical system and reduce mechanical blur during reduction, the rotational speed of the photoreceptor, that is, the scanning process speed, is set to the speed at non-magnification (during magnification).

ＶからＶ′に下げた場合、転写帯電器ではその出力を変
え、転写材に対し常に＋Ｑｏなる電荷を付与臥十分な転
写を得るものの、分離帯電器の出力が一定であったため
、非変倍時の付与電荷−ＱＯに対しν′ 縮小時は−Ｑ×−なる電荷しか付与されず、転ν 写材上の電荷を中和しきれないため、分離不可となって
いた。また、拡大時、光量不足を補うためにプロセス・
スピードを下げた場合も、上記と同様の理由によ如分離
不可であった。When lowering from V to V', the transfer charger changes its output and always applies a charge of +Qo to the transfer material.Although sufficient transfer is obtained, the output of the separation charger remains constant, so there is no variable magnification. Compared to the charge -QO applied during ν' reduction, only a charge of -Q×- is applied, and the charge on the transfer material cannot be completely neutralized, making it impossible to separate. In addition, when enlarging, the process
Even when the speed was lowered, separation was not possible for the same reason as above.

本発明は、上述の難点を除去し、感光体の周回速度が変
動した場合においても、安定した転写材分離を行表い分
離帯電装置の提供を目的とする。SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a separation and charging device that stably separates a transfer material even when the rotational speed of a photoreceptor varies.

本発明は像保持体に接している転写材とコロナ放電によ
り静電的に像保持体面から分離する分離帯電装置におい
て、像保持体の周速度に応じて分離帯電量を変動させた
分離帯電装置である。The present invention is a separation charging device that electrostatically separates a transfer material in contact with an image carrier from the surface of the image carrier by corona discharge, in which the separation charging amount is varied in accordance with the circumferential speed of the image carrier. It is.

以下図面に基づいて本発明の詳細な説明する。The present invention will be described in detail below based on the drawings.

第２図は本発明の実施例を示す概略図である。FIG. 2 is a schematic diagram showing an embodiment of the present invention.

図は電子写真装置の感光体周辺部を駆動側から見たもの
で、１２１を感光体１と同軸上にあシ感光体を周動させ
るギアであシ、１３は駆動モーター（不図示）と同軸上
にあり感光体駆動ギア１２と噛合って感光体に周動力を
伝達するギアである。The figure shows the area around the photoreceptor of an electrophotographic device viewed from the drive side, where 121 is a gear that rotates the photoreceptor coaxially with the photoreceptor 1, and 13 is a drive motor (not shown). This gear is coaxial and meshes with the photoreceptor drive gear 12 to transmit circumferential force to the photoreceptor.

１４はギア１６と噛合って周動する鋸歯状の円板で、１
５Ｆｉこの円板をはさむ様に位置するフォトインタラプ
タである。８，９は各々第１図に示した転写及び分離帯
電器である。14 is a serrated disk that meshes with the gear 16 and rotates;
5Fi is a photointerrupter located across this disk. 8 and 9 are transfer and separation chargers shown in FIG. 1, respectively.

上記中フォトインタラプタ（１−５は円板１４の周動に
よ如クロックパルスを発し、そのパルスの周期によ）駆
動モーター乃至感光体の周動速度をモニターすることが
可能である。この周動速度のモニターは常時ＣＰＵ１６
によ）行なわれる。従って変倍時感党体の周動速度を変
化させた場合、この変化はＣＰＵ１６によシ検知されそ
の変化由に応じ分離帯電器８に印加する電圧乃至電流を
変動させるべくＣＰＵ１６よ如ＨＶＴ１７（出カドラン
ス）に信号が送られる。It is possible to monitor the rotational speed of the drive motor or the photoreceptor using the above-mentioned photointerrupter (1-5 emits clock pulses according to the rotation of the disk 14, and the period of the pulses). This circumferential speed is constantly monitored by the CPU 16.
(by) is carried out. Therefore, when changing the circumferential speed of the sensing element during zooming, this change is detected by the CPU 16, and the HVT 17 ( A signal is sent to the output (output transceiver).

例えば縮小時、光学系の移動に件な５ブレを抑制するた
め、周動速度を下げた場合、ＣＰＵがこれを検知し分離
帯電器８への印加電圧又は電流を下げる様に信号が送ら
れる。For example, when reducing the circumferential speed in order to suppress blur caused by the movement of the optical system, the CPU detects this and sends a signal to reduce the voltage or current applied to the separation charger 8. .

これによシ感光体に接している転写材に対して再転写を
起こさない程度に、しかし転写材上の電荷を中和するに
十分な除電を行なわしめ、転写材は安定して分離される
。また、拡大時に露光量の不足を補うため周動速度を下
げた場合、ＣＰＵよル転写帯電器８へ印加電圧電流を下
げる様に信号が送られる。これによル上記同様再転子を
起こさない程度に十分に転写材上の電荷を中和せしめ、
安定した分離を可能としている。This removes the charge on the transfer material that is in contact with the photoconductor to the extent that re-transfer does not occur, but is sufficient to neutralize the charge on the transfer material, and the transfer material is stably separated. . Further, when the peripheral speed is lowered to compensate for the lack of exposure amount during enlargement, a signal is sent to the CPU transfer charger 8 to lower the applied voltage and current. This neutralizes the electric charge on the transfer material sufficiently to prevent retrochanterization as described above.
This enables stable separation.

上述の実施例では、変速時に分離帯電器に印加する全電
圧又祉全電流を変動させた例を示したが、上述以外にも
例えば帯電器のシールド板に予め可変抵抗を付与してお
き、変速時この抵抗値を変え、転写材に向う電流分（電
荷量）を変え、再転写を起こさない程度でかつ転写材上
の電荷を中和するに十分な除電量を付与せしめる様にし
てもよい。In the above-mentioned embodiment, an example was shown in which the total voltage or total current applied to the separation charger was varied during speed change, but in addition to the above, for example, a variable resistance may be provided in advance to the shield plate of the charger, Even if this resistance value is changed when changing speed, the amount of current (charge amount) directed to the transfer material is changed, and the amount of static electricity removed is applied to an extent that does not cause re-transfer and is sufficient to neutralize the charge on the transfer material. good.

次に変倍時の速度変化率と分離帯電の出力変化率を比較
してみた。速度変化率ν／ｖｏｃｗ・０は元の速度、ν
は変化後の速度）が小さい場合、感光体と転写材の密着
性が機械的に十分である場合は転写帯電量を変えなくと
も十分な転写効率を得ることはすでに見出されている。Next, I compared the speed change rate during zooming and the output change rate during separation charging. The speed change rate ν/vocw・0 is the original speed, ν
It has already been found that sufficient transfer efficiency can be obtained without changing the amount of transfer charge if the adhesion between the photoreceptor and the transfer material is mechanically sufficient and the transfer speed (speed after change) is small.

そこでこの場合分離帯電の出力をどの程度室えれば良い
のか実験を行ないその結果を第３図に示した。この図の
横軸は速度変化率、縦軸は帯電出力の変化率ｖ／ｖｏ　
（ｖｅは元の出力電圧、ｖｉ；を変化後の出力電圧）を
取っている。この図よυ次の２点が分かる。Therefore, an experiment was conducted to find out how much the output of the separation charging should be increased in this case, and the results are shown in FIG. In this figure, the horizontal axis is the speed change rate, and the vertical axis is the charging output change rate v/vo.
(ve is the original output voltage, vi is the output voltage after changing). This figure shows the following two points.

（１）転写帯電の出力を一定とした場合にも分離帯電の
出力を変えることが望ましい。(1) Even when the output of transfer charging is constant, it is desirable to change the output of separation charging.

（閤）その出力の変化率は感光体の速度変化率よりも小
とすることが望ましい。It is desirable that the rate of change in the output is smaller than the rate of change in the speed of the photoreceptor.

以上の説明から明らか々様に本発明は像保持体の周動速
度に応じて分離帯電量を変動させることにより再転写を
起こすことなく、安定した分離を行なわせることが可能
となった。As is clear from the above description, the present invention makes it possible to perform stable separation without causing retransfer by varying the separation charge amount in accordance with the circumferential speed of the image carrier.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来の電子写真装置の概略図、第２図は本発明
の実施例を示す概略図、第３図は速度変化率に対する帯
電出力の変化率を宍わすグラフである。 図において、１・・・・・感光体、８・・・・・分離帯
電器、９・φ・・・転写帯電器、１６−−・・・ＣＰＵ
。 １７・・・・・ＨＶＴ、を表わす。 出願人　キャノン株式会社 新変化竿％。FIG. 1 is a schematic diagram of a conventional electrophotographic apparatus, FIG. 2 is a schematic diagram showing an embodiment of the present invention, and FIG. 3 is a graph showing the rate of change in charging output with respect to the rate of change in speed. In the figure, 1...Photoconductor, 8...Separation charger, 9.φ...Transfer charger, 16--...CPU
. 17...represents HVT. Applicant Canon Co., Ltd. New Change Rod%.

Claims (2)

【特許請求の範囲】[Claims] （１）像保持体に接している転写材とコロナ放電によ）
静電的に像保持体面から分離する分離帯電装置において
、像保持体の周速度に応じて分離帯電量を変動させるこ
とを特徴とする分離帯電装置。(1) Due to the transfer material in contact with the image carrier and corona discharge)
A separation and charging device that electrostatically separates an image carrier from a surface thereof, the separation and charging device being characterized in that the amount of separation charge is varied in accordance with the circumferential speed of the image carrier. （２）像保持体の周動速度の変化率よりも分離帯電器の
出力変化率が小となる様な範囲において分離帯電器の出
力を変動させることを特徴とする特許請求範囲第１項記
載の分離帯電装置。(2) The output of the separation charger is varied within a range such that the rate of change in the output of the separation charger is smaller than the rate of change in the circumferential velocity of the image carrier. separation charging device.