JP2005258288A - Transfer method and image forming apparatus using the transfer method - Google Patents

Transfer method and image forming apparatus using the transfer method Download PDF

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JP2005258288A
JP2005258288A JP2004072673A JP2004072673A JP2005258288A JP 2005258288 A JP2005258288 A JP 2005258288A JP 2004072673 A JP2004072673 A JP 2004072673A JP 2004072673 A JP2004072673 A JP 2004072673A JP 2005258288 A JP2005258288 A JP 2005258288A
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transfer
transfer material
forming apparatus
paper type
image forming
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JP4355597B2 (en
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Ryoji Imai
亮二 今井
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Ricoh Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer method by which transfer material separation performance is enhanced and to provide an image forming apparatus using the transfer method. <P>SOLUTION: In the transfer method for transferring such that a toner image held on a photoreceptor drum 1 is brought into contact with the transfer material, the paper type data of the transfer material is obtained from pressure detected by a pressure sensor 37 and the width of a transfer nip between the transfer material, and the photoreceptor drum 1 is altered in the course of the transfer. Thereby the transfer material is steadily separated from a photoreceptor drum 1 according to the paper type. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、転写方法及びその転写方法を用いる画像形成装置に関す
るものである。 The present invention relates to a transfer method and an image forming apparatus using the transfer method.

像担持体表面にトナー像を形成し、そのトナー像を直に転写材上に転写し、または像担持体としての中間転写体に担持したトナー像を転写材に転写する形式の電子複写機、プリンタ、ファクシミリ或いはその少なくとも２つの機能を備えた複合機などとして構成される画像形成装置は従来より周知である。   An electronic copying machine of a type in which a toner image is formed on the surface of an image carrier and the toner image is directly transferred onto a transfer material, or a toner image carried on an intermediate transfer body as an image carrier is transferred to a transfer material; 2. Description of the Related Art Image forming apparatuses configured as printers, facsimiles, or multifunction machines having at least two functions thereof are conventionally known.

かかる画像形成装置の一例として、転写材搬送部材上に転写材を担持して搬送し、その転写材を像担持体表面に当接させると共に、該転写材搬送部材の表面と反対側の転写材搬送部材の裏面に導電性部材を当接させ、その導電性部材に電圧を印加することにより、像担持体表面のトナー像を転写材に転写する転写装置を備えた画像形成装置が知られている。   As an example of such an image forming apparatus, a transfer material is carried and conveyed on a transfer material conveyance member, the transfer material is brought into contact with the surface of the image carrier, and the transfer material on the side opposite to the surface of the transfer material conveyance member 2. Description of the Related Art An image forming apparatus having a transfer device that transfers a toner image on a surface of an image carrier onto a transfer material by bringing a conductive member into contact with the back surface of a conveying member and applying a voltage to the conductive member is known. Yes.

この種の画像形成装置において、転写性能を高めるのは転写材の像担持体への接触幅、すなわち転写ニップ幅を広くとることであり、転写ニップ幅が大きい程転写率の低下による異常画像の発生を抑えられる。しかしながら、転写ニップ幅が大きいと、転写材は像担持体への接触面積が大きいため、像担持体に巻き付き易くなってしまい、分離性が悪化するという問題が発生した。   In this type of image forming apparatus, the transfer performance is improved by increasing the contact width of the transfer material to the image carrier, that is, the transfer nip width. The larger the transfer nip width, the lower the transfer rate. Occurrence can be suppressed. However, when the transfer nip width is large, the transfer material has a large contact area with the image carrier, so that the transfer material is easily wound around the image carrier, resulting in a problem that the separation property deteriorates.

本発明は、上記した従来の不具合を解消し、転写材の分離性能を高められる転写方法及び該転写方法を用いる画像形成装置を提供することを目的としている。   An object of the present invention is to provide a transfer method capable of solving the above-described conventional problems and improving the separation performance of a transfer material, and an image forming apparatus using the transfer method.

上記目的を達成するため、本発明は、像担持体上に担持されたトナー像を転写材に当接させて転写する転写方法において、前記転写材の紙種データを紙種検知手段から得て、この紙種データに基づいて転写時の前記転写材と前記像担持体との当接条件を可変することを特徴としている。   In order to achieve the above object, according to the present invention, in a transfer method for transferring a toner image carried on an image carrier by contacting the transfer material, paper type data of the transfer material is obtained from a paper type detection unit. The contact condition between the transfer material and the image carrier at the time of transfer is varied based on the paper type data.

なお、本発明の転写方法において、前記可変する当接条件が転写ニップ形成条件であり、前記紙種データにより転写材搬送方向における転写ニップ幅の長さを可変すると、効果的である。   In the transfer method of the present invention, the variable contact condition is a transfer nip formation condition, and it is effective if the length of the transfer nip width in the transfer material conveyance direction is changed by the paper type data.

さらに、本発明の転写方法において、前記転写材の先端が転写ニップ幅の中心に達するタイミングで前記当接条件を可変すると、効果的である。
また、上記目的を達成するため、本発明は、請求項１ないし３の何れかに記載の転写方法を用いる画像形成装置において、トナー像を担持する像担持体と、該像担持体に当接し、転写材を搬送する転写搬送部材を有する転写装置と、前記転写搬送部材を前記像担持体に接離する方向へ移動して前記転写搬送手段の前記像担持体への当接圧を可変する当接圧可変手段と、前記転写材の紙種データを検知する紙種検知手段とを有することを特徴としている。 Furthermore, in the transfer method of the present invention, it is effective if the contact condition is varied at the timing when the leading edge of the transfer material reaches the center of the transfer nip width.
In order to achieve the above object, the present invention provides an image forming apparatus using the transfer method according to any one of claims 1 to 3, an image carrier that carries a toner image, and an abutting contact with the image carrier. And a transfer device having a transfer conveying member that conveys the transfer material, and moving the transfer conveying member in a direction in contact with and separating from the image carrier to vary the contact pressure of the transfer carrier to the image carrier. It has a contact pressure varying means and a paper type detecting means for detecting the paper type data of the transfer material.

なお、本発明の画像形成装置において、前記転写搬送部材が複数のローラに巻き掛けられた無端状の転写ベルトであると、効果的である。
さらに、本発明の画像形成装置において、前記紙種検知手段が転写材搬送方向における転写領域の上流側に配置された一対の搬送ローラに設けられた圧力センサであり、該圧力センサが前記搬送ローラにかかる圧力から転写材の厚みデータを検知すると、効果的である。 In the image forming apparatus of the present invention, it is effective that the transfer conveying member is an endless transfer belt wound around a plurality of rollers.
Furthermore, in the image forming apparatus of the present invention, the paper type detection unit is a pressure sensor provided on a pair of conveyance rollers disposed upstream of the transfer region in the transfer material conveyance direction, and the pressure sensor is the conveyance roller. It is effective to detect the thickness data of the transfer material from the pressure applied to.

さらにまた、本発明の画像形成装置において、前記一対の搬送ローラがレジストローラであると、効果的である。
さらにまた、本発明の画像形成装置において、前記紙種検知手段がホストコンピュータへ入力された値を読み取る装置であると、効果的である。 Furthermore, in the image forming apparatus of the present invention, it is effective that the pair of transport rollers are registration rollers.
Furthermore, in the image forming apparatus of the present invention, it is effective that the paper type detection unit reads the value input to the host computer.

さらにまた、本発明の画像形成装置において、前記ホストコンピュータへ入力された値はオペレーションパネルから入力されたものであると、効果的である。   Furthermore, in the image forming apparatus of the present invention, it is effective that the value input to the host computer is input from the operation panel.

請求項１及び２の構成によれば、紙種検知手段から得られる紙種データから、転写工程において転写材と像担持体との当接条件を可変としたので、紙種に応じて、転写材が安定して像担持体から分離できる転写方法が提供することができる。   According to the first and second aspects of the present invention, the contact condition between the transfer material and the image carrier is made variable in the transfer process from the paper type data obtained from the paper type detection means. It is possible to provide a transfer method in which the material can be stably separated from the image carrier.

請求項３の構成によれば、当接条件を可変するタイミングを転写材の先端が転写ニップ幅の中心に達するときとしたので、転写材の先端が分離に最適な転写ニップ幅とし、トナー像が転写される転写領域では転写性が最適となる転写ニップ幅に可変することができる。   According to the third aspect of the present invention, the timing for changing the contact condition is set when the leading edge of the transfer material reaches the center of the transfer nip width. In the transfer area where the toner is transferred, the transfer nip width can be varied so that the transfer property is optimum.

請求項４の構成によれば、紙種検知手段から得られる紙種データから、転写工程において転写材と像担持体との当接条件を可変としたので、紙種に応じて、転写材が安定して像担持体から分離できる画像形成装置が提供することができる。   According to the configuration of the fourth aspect, since the contact condition between the transfer material and the image carrier is made variable in the transfer process from the paper type data obtained from the paper type detection means, the transfer material is changed according to the paper type. An image forming apparatus that can be stably separated from the image carrier can be provided.

請求項５の構成によれば、転写ニップ幅の可変が行い易い。
請求項６及び７の構成によれば、圧力センサから得られる圧力データから、転写工程において転写材と像担持体との当接条件を可変するので、圧力から検知した紙種から転写材に最適な当接条件にすることができる。 According to the configuration of the fifth aspect, the transfer nip width can be easily changed.
According to the configurations of claims 6 and 7, since the contact condition between the transfer material and the image carrier is changed in the transfer process from the pressure data obtained from the pressure sensor, it is optimal for the transfer material from the paper type detected from the pressure. It is possible to make a proper contact condition.

請求項８及び９の構成によれば、ホストコンピュータへ入力された紙種データから、転写工程において前記転写材と前記像担持体との当接条件を可変としたので、紙種に応じて、転写材が安定して像担持体から分離できる画像形成装置が提供することができる。   According to the configuration of claims 8 and 9, since the contact condition between the transfer material and the image carrier in the transfer process is variable from the paper type data input to the host computer, according to the paper type, An image forming apparatus capable of stably separating the transfer material from the image carrier can be provided.

以下、本発明の実施の形態を添付図面にしたがって説明する。
図１は、本発明の一実施形態の主要部を示す概略図である。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic view showing the main part of one embodiment of the present invention.

図１において、像担持体としての感光体ドラム１は、図示していない画像形成装置本体の機枠に対して回転自在に支持され、画像形成動作時に図１における時計方向（矢印Ａ方向）に回転駆動される。このとき帯電装置（図示していない）により感光体表面が所定の極性（例えばマイナス極性）に均一に帯電される。かかる帯電面に対し、像露光装置の一例であるレーザ書き込みユニット（図示せず）から出射する光変調されたレーザ光が照射され、これによって感光体表面に画信号に対応する静電潜像が形成される。このようにして形成された静電潜像は現像装置によってトナー像として可視像化され、潜像がトナー像化される。   In FIG. 1, a photosensitive drum 1 as an image carrier is rotatably supported with respect to a machine frame of an image forming apparatus main body (not shown), and rotates clockwise (arrow A direction) in FIG. 1 during an image forming operation. Driven by rotation. At this time, the surface of the photoreceptor is uniformly charged to a predetermined polarity (for example, negative polarity) by a charging device (not shown). The charged surface is irradiated with light-modulated laser light emitted from a laser writing unit (not shown) which is an example of an image exposure apparatus, whereby an electrostatic latent image corresponding to an image signal is formed on the surface of the photoreceptor. It is formed. The electrostatic latent image formed in this manner is visualized as a toner image by the developing device, and the latent image is converted into a toner image.

感光体ドラム１上に形成されたトナー像は、転写装置２によって、転写紙などの転写材に転写される。ここに示した転写装置２は、複数のローラ、図の例では駆動ローラ４と従動ローラ５の２つのローラに巻き掛けられた無端状の転写ベルト３を有し、図示していない駆動装置によって、駆動ローラ４が図１における反時計方向に回転駆動され、これによって転写ベルト３が矢印Ｂ方向に駆動される。転写ベルト３は、所定の抵抗、例えば１０４乃至１０９Ω・cm、特に１０５乃至１０６Ω・cm程の体積抵抗率を有する中抵抗体より成り、例えばゴムなどの可撓性材料によって構成されている。 The toner image formed on the photosensitive drum 1 is transferred to a transfer material such as transfer paper by the transfer device 2. The transfer device 2 shown here has an endless transfer belt 3 wound around a plurality of rollers, two rollers of a driving roller 4 and a driven roller 5 in the example shown in the figure, and is driven by a driving device (not shown). The drive roller 4 is rotationally driven in the counterclockwise direction in FIG. 1, whereby the transfer belt 3 is driven in the arrow B direction. The transfer belt 3 is made of a medium resistor having a predetermined resistance, for example, a volume resistivity of about 10 4 to 10 9 Ω · cm, particularly about 10 5 to 10 6 Ω · cm, and is made of a flexible material such as rubber, for example. It is configured.

一方、図示していない給紙部から送り出された転写材は、レジストローラ１０に先端が突き当たって一時停止された後、そのレジストローラ１０によりその表面に、感光体ドラム１上のトナー像が正しく転写されるタイミングで、互いに当接した転写ベルト３と感光体ドラム１との間に矢印Ｃで示す方向に給送される。このようにして、転写材には、トナー像の形成された感光体ドラム１に当接しながら、転写ベルト３上に担持されて搬送される。転写ベルト３は、転写材を担持して搬送しつつ、その転写材をトナー像の形成された像担持体に当接させる転写材搬送部材の一例を構成している。   On the other hand, the transfer material fed from a paper supply unit (not shown) is temporarily stopped by abutting against the registration roller 10, and then the registration roller 10 causes the toner image on the photosensitive drum 1 to be correctly applied to the surface thereof. At the transfer timing, the sheet is fed in the direction indicated by the arrow C between the transfer belt 3 and the photosensitive drum 1 that are in contact with each other. In this manner, the transfer material is carried on the transfer belt 3 and conveyed while being in contact with the photosensitive drum 1 on which the toner image is formed. The transfer belt 3 constitutes an example of a transfer material conveying member that supports and conveys a transfer material while bringing the transfer material into contact with an image carrier on which a toner image is formed.

また、感光体ドラム１が直接又は転写材を介して接触する転写ベルト３の表面と反対側の転写ベルト裏面には、転写ローラ６が当接している。この転写ローラ６は、感光体ドラム１と転写ベルト３との接触領域であるニップ部７よりも転写材搬送方向下流側の転写ベルト部分の裏面に接触している。かかる転写ローラ６には、電源装置（図示せず）が接続されており、感光体ドラム１と転写ベルト３との間に転写材が搬送されてくると、電源装置から転写ローラ６に、感光体上のトナー像の帯電極性と逆の極性（本例ではプラス極性）の電圧が印加され、これにより転写ベルト３が帯電し、感光体ドラム１と転写ベルト３との電位差で感光体ドラム１へ電流が流れ、感光体上のトナー像が転写材上に転写される。感光体ドラム１と転写材との間に転写電界が形成され、その電界の作用により、転写ベルト３に担持されて搬送される転写材の表面にトナー像が静電的に転写されるのである。なお、転写後の感光体ドラム１は図示していないクリーニング装置によって残留トナーが除去され、さらに残留電荷が除電装置（図示せず）によって除電される。   The transfer roller 6 is in contact with the back surface of the transfer belt opposite to the surface of the transfer belt 3 with which the photosensitive drum 1 contacts directly or via a transfer material. The transfer roller 6 is in contact with the back surface of the transfer belt portion on the downstream side in the transfer material conveyance direction with respect to the nip portion 7, which is a contact area between the photosensitive drum 1 and the transfer belt 3. A power supply device (not shown) is connected to the transfer roller 6, and when the transfer material is conveyed between the photosensitive drum 1 and the transfer belt 3, the transfer roller 6 is exposed to the transfer roller 6. A voltage having a polarity opposite to the charging polarity of the toner image on the body (positive polarity in this example) is applied, whereby the transfer belt 3 is charged, and the photosensitive drum 1 is subjected to a potential difference between the photosensitive drum 1 and the transfer belt 3. Current flows, and the toner image on the photoreceptor is transferred onto the transfer material. A transfer electric field is formed between the photosensitive drum 1 and the transfer material, and the toner image is electrostatically transferred onto the surface of the transfer material carried and transported on the transfer belt 3 by the action of the electric field. . Note that the toner remaining on the photosensitive drum 1 after the transfer is removed by a cleaning device (not shown), and the residual charge is discharged by a charge removal device (not shown).

転写装置２は、駆動ローラ４及び従動ローラ５に巻き掛けられた転写ベルト３が１つのユニットとして構成され、このユニットは感光体ドラム１に対して接離する方向に揺動可能に装着されている。例えば、駆動ローラ４の軸を中心として従動ローラ５側が回動可能に装着されている。そして、転写ベルト３の従動ローラ側下部には不図示のステッピングモータによって回転する転写接離カム１１が設けられ、該カムのカム面には押し上げレバー１２の一端が当接されている。押し上げレバー１２は軸１３を中心に回動可能に図示していない側板に装着され、不図示のばね等の弾性部材によってカム１１に当接する方向、すなわち時計方向の回動力が付勢されている。   The transfer device 2 includes a transfer belt 3 wound around a driving roller 4 and a driven roller 5 as one unit, and this unit is mounted so as to be swingable in a direction in which it is in contact with and away from the photosensitive drum 1. Yes. For example, the driven roller 5 side is rotatably mounted around the axis of the drive roller 4. A transfer contact / separation cam 11 that is rotated by a stepping motor (not shown) is provided on the lower portion of the transfer belt 3 on the driven roller side, and one end of a push-up lever 12 is in contact with the cam surface of the cam. The push-up lever 12 is mounted on a side plate (not shown) so as to be rotatable about a shaft 13, and a turning force in a direction contacting the cam 11, that is, clockwise, is urged by an elastic member such as a spring (not shown). .

かかる構成により転写接離カム１１が回転することにより押し上げレバー１２を介して転写ベルト３が上下動し、転写ニップ７の幅が可変される。なお、符号１４は転写ベルト３のトナー等の汚れ除去するクリーニング装置であり、クリーニング装置１４は転写ベルト３に接するクリーニングブレード１５及びクリーニングバイアスローラ１６、回収トナー等を図示していない回収ボックス等へ搬送するトナー回収コイル１７、クリーニングバイアスローラ１６に付着した汚れを掻き落とすバイアスローラ用ブレード１８から構成されている。   With this configuration, when the transfer contact / separation cam 11 rotates, the transfer belt 3 moves up and down via the push-up lever 12, and the width of the transfer nip 7 is varied. Reference numeral 14 denotes a cleaning device for removing dirt such as toner on the transfer belt 3. The cleaning device 14 supplies a cleaning blade 15 and a cleaning bias roller 16 that are in contact with the transfer belt 3, a collected toner, and the like to a collection box (not shown). The toner collecting coil 17 is conveyed, and the bias roller blade 18 is used to scrape off dirt adhering to the cleaning bias roller 16.

このように構成された転写装置２は、紙種によって感光体ドラム１へ巻き付きやすくなり分離性が悪化する。この分離性が問題になるのは転写材に腰の弱い薄紙を用いた場合であり、そこで紙種と転写ニップ幅とにおける分離性の善し悪しの関係について調べた。その結果を図２に示す。この実験では、上記転写装置２を用い、転写ニップ幅７を６ｍｍ、８ｍｍ、１０ｍｍの３段階に切り替え、転写材には薄紙に分類される４５Ｋ紙、普通紙に分類される６５Ｋ紙、薄紙と普通紙との中間の５５Ｋ紙を用いた。   The transfer device 2 configured in this manner is easily wound around the photosensitive drum 1 depending on the paper type, and the separation property is deteriorated. This separability becomes a problem when thin paper with low stiffness is used as the transfer material, and the relationship between the quality of the separability between the paper type and the transfer nip width was investigated. The result is shown in FIG. In this experiment, the transfer device 2 is used, and the transfer nip width 7 is switched to three stages of 6 mm, 8 mm, and 10 mm, and the transfer material is 45K paper classified as thin paper, 65K paper classified as plain paper, and thin paper. An intermediate 55K paper with plain paper was used.

その結果、６５Ｋ紙の場合、転写ニップ幅が６ｍｍ、８ｍｍ、１０ｍｍの何れの場合においても分離性が良好であった。５５Ｋ紙の場合、転写ニップ幅が６ｍｍ、８ｍｍの場合、分離性が良好であったが、１０ｍｍでは何回か感光体への巻き付きが発生した。４５Ｋ紙では転写ニップ幅が６ｍｍだけ良好で、８ｍｍ、１０ｍｍでは分離性に問題があった。   As a result, in the case of 65K paper, the separability was good regardless of whether the transfer nip width was 6 mm, 8 mm, or 10 mm. In the case of 55K paper, when the transfer nip width was 6 mm and 8 mm, the separability was good, but at 10 mm, winding around the photoconductor occurred several times. With 45K paper, the transfer nip width was good only by 6 mm, and when it was 8 mm and 10 mm, there was a problem in separability.

この結果から、５５Ｋ紙の場合では転写ニップ幅は８ｍｍ程度に、４５Ｋ紙以下の薄紙では転写ニップ幅は６ｍｍ程度に狭めることが必要であることが判った。
図３は、本発明の一実施形態を示す画像形成装置の回路構成図である。図３において、メイン制御部３０はＣＰＵ３１、ＲＯＭ３２、ＲＡＭ３３、入力回路３４、モータドライバ３５及び入出力装置３６を有し、紙種検知手段としての圧力センサ３７及びオペレーションパネル３９が接続され、さらに転写接離カム１１を回転するステッピングモータ３８と接続されている。圧力センサ３７は、転写材搬送方向における転写ニップ７の上流側の搬送ローラ対に設けられ、本例ではレジストローラ端部に配置され、転写材がレジストローラ１０を通過する際に転写材の厚さを圧力で検知する。 From this result, it was found that the transfer nip width needs to be reduced to about 8 mm in the case of 55K paper, and the transfer nip width to about 6 mm in the thin paper of 45K paper or less.
FIG. 3 is a circuit configuration diagram of the image forming apparatus showing an embodiment of the present invention. In FIG. 3, the main control unit 30 has a CPU 31, ROM 32, RAM 33, input circuit 34, motor driver 35, and input / output device 36, and is connected with a pressure sensor 37 and an operation panel 39 as paper type detecting means, and further transferred. The contact cam 11 is connected to a stepping motor 38 that rotates the contact / separation cam 11. The pressure sensor 37 is provided on the pair of conveyance rollers upstream of the transfer nip 7 in the transfer material conveyance direction, and is disposed at the end of the registration roller in this example, and the thickness of the transfer material when the transfer material passes through the registration roller 10. This is detected by pressure.

図４は、レジストローラ１０に設けた圧力センサ３７の検知値と転写材の厚みとの関連を示す図で、ＣＰＵ３１に入力された検知圧力値がほぼ０．５Ｎ／ｍならば薄紙に分類される４５Ｋ紙で、０．６Ｎ／ｍならば一般的な普通紙に分類される６５Ｋ紙で、０．５５Ｎ／ｍならば薄紙と普通紙との中間の５５Ｋ紙と判断される。   FIG. 4 is a diagram showing the relationship between the detected value of the pressure sensor 37 provided on the registration roller 10 and the thickness of the transfer material. If the detected pressure value input to the CPU 31 is approximately 0.5 N / m, it is classified as thin paper. If it is 0.6K / m, it is 65K paper classified as general plain paper, and if it is 0.55N / m, it is judged as 55K paper which is intermediate between thin paper and plain paper.

ＣＰＵ３１はこの画像形成装置の通常動作時（例えば通紙時）に圧力センサ３７から入力回路３４を介して入力される圧力検知信号により圧力センサ３７によって薄い転写材と判断された場合、検知圧力が所定の値、例えば０．５Ｎ／ｍより小さい場合にはモータドライバ３５を介してステッピングモータ３８に所定の信号を入力することでステッピングモータ３８に接続されている転写接離カム１１の角度を制御して、転写ベルト３の感光体ドラム１側への移動量を変化させ、転写ニップ幅を６ｍｍに変更する。   When the CPU 31 determines that the transfer material is a thin transfer material by the pressure sensor 37 based on the pressure detection signal input from the pressure sensor 37 via the input circuit 34 during the normal operation of the image forming apparatus (for example, during paper passing), the detected pressure is When the value is smaller than a predetermined value, for example, 0.5 N / m, the angle of the transfer contact / separation cam 11 connected to the stepping motor 38 is controlled by inputting a predetermined signal to the stepping motor 38 via the motor driver 35. Then, the amount of movement of the transfer belt 3 toward the photosensitive drum 1 is changed, and the transfer nip width is changed to 6 mm.

転写工程をこのように制御することにより、４５Ｋ紙以下の薄紙でも良好な分離性が得られた。
ところで、上記例の場合、転写ニップ幅が６ｍｍであればすべての紙種において分離性が良好であるので、転写ニップ幅を６ｍｍに固定して使用すれば良く、これを可変する必要がないように思える。しかし、転写ニップ幅が狭いと転写材が感光体ドラム１に接触する面積が小さく転写率が低下して画像品質に悪影響が出てしまう。 By controlling the transfer process in this way, good separation was obtained even on thin paper of 45K paper or less.
By the way, in the case of the above example, if the transfer nip width is 6 mm, the separation property is good for all paper types. Therefore, the transfer nip width may be fixed at 6 mm, and this need not be changed. It seems to be. However, if the transfer nip width is narrow, the area where the transfer material comes into contact with the photosensitive drum 1 is small and the transfer rate is lowered, which adversely affects the image quality.

そこで、本発明では紙種データに基づいて分離性が良好となる範囲で転写ニップ幅をできる限り大きく取るように構成している。例えば、上記実験例では６５Ｋ紙の場合、転写ニップ幅を１０ｍｍに、５５Ｋ紙では転写ニップ幅を８ｍｍに、そして４５Ｋ紙だけ転写ニップ幅を６ｍｍにそれぞれ可変して転写するものである。   Therefore, in the present invention, the transfer nip width is set as large as possible within a range in which the separability is good based on the paper type data. For example, in the above experimental example, the transfer nip width is changed to 10 mm for 65K paper, the transfer nip width to 8 mm for 55K paper, and the transfer nip width for 45K paper to 6 mm.

このように構成された転写装置２は、分離性が良好な範囲で転写ニップ幅が大きくとることで、転写率の低下が少ない良好な画像転写が得られる。しかし、このように構成しても４５Ｋ紙以下の薄紙では転写ニップ幅の狭さから画質の落ちる記録物が生ずることが起り得る。   The transfer device 2 configured as described above can obtain a good image transfer with little reduction in transfer rate by taking a large transfer nip width in a range in which the separability is good. However, even with such a configuration, on a thin paper of 45K paper or less, a recorded matter with a lowered image quality may occur due to the narrow transfer nip width.

転写材の感光体ドラム１への巻き付きはその先端が分離しやすければそれ以降トナー像が転写される転写領域の部分も先端に追随して分離し易い。そこで、転写ニップ幅を可変するタイミングを転写材の先端が転写ニップ幅の中心に達したタイミングに設定する。例えば、圧力センサ３７によって薄い転写材と判断された場合、検知圧力が所定の値、例えば０．５Ｎ／ｍより小さい場合にはモータドライバ３５を介してステッピングモータ３８に所定の信号を入力することでステッピングモータ３８に接続されている転写接離カム１１の角度を制御して、転写ベルト３の感光体ドラム１側への移動量を変化させ、転写材の先端部が転写ニップ７の中心にくるタイミングで転写ニップ幅を６ｍｍとして、それ以降のトナーが乗っている転写領域では転写ニップ幅を８ｍｍに変更する。   When the transfer material is wound around the photosensitive drum 1, if the front end is easily separated, the portion of the transfer area where the toner image is transferred thereafter follows the front end and is easily separated. Therefore, the timing for changing the transfer nip width is set to the timing when the leading edge of the transfer material reaches the center of the transfer nip width. For example, when the pressure sensor 37 determines that the transfer material is thin, if the detected pressure is smaller than a predetermined value, for example, 0.5 N / m, a predetermined signal is input to the stepping motor 38 via the motor driver 35. Then, the angle of the transfer contact / separation cam 11 connected to the stepping motor 38 is controlled to change the amount of movement of the transfer belt 3 toward the photosensitive drum 1 so that the leading edge of the transfer material is placed at the center of the transfer nip 7. The transfer nip width is set to 6 mm at the coming timing, and the transfer nip width is changed to 8 mm in the transfer area where the toner is placed thereafter.

このように転写ニップ幅を可変するタイミングを、転写材の先端部が転写ニップ７の中心にくるタイミングにすることで、分離性と転写性とを共に満足する転写が得られる。   In this way, by setting the timing for changing the transfer nip width to the timing at which the leading end portion of the transfer material comes to the center of the transfer nip 7, transfer that satisfies both separation and transferability can be obtained.

なお、上記実施形態では紙種検知手段として圧力センサ３７の検知圧力値をＣＰＵ３１に入力し紙種をデータとして用いたが、ユーザが使用する転写材に基づいてオペレーションパネル３９からＣＰＵ３１に入力する値から紙種を判別してニップ幅の制御を行っても同様の効果が得られる。   In the above embodiment, the detected pressure value of the pressure sensor 37 is input to the CPU 31 as the paper type detecting means and the paper type is used as data. However, the value input to the CPU 31 from the operation panel 39 based on the transfer material used by the user. The same effect can be obtained by controlling the nip width by discriminating the paper type.

また、上記実施形態では像担持体を感光体ドラムとしたが、像担持体は感光体ベルト、さらには中間転写体であってもよく、さらにまた転写搬送部材は転写ベルトに限らず、像担持体に当接する転写ローラであっても良い。   In the above embodiment, the image carrier is a photosensitive drum. However, the image carrier may be a photosensitive belt or an intermediate transfer member, and the transfer conveying member is not limited to the transfer belt, and the image carrier may be used. It may be a transfer roller that contacts the body.

本発明の一実施形態を示す画像形成装置の主要部の断面図である。1 is a cross-sectional view of a main part of an image forming apparatus showing an embodiment of the present invention. 転写ニップ幅と紙の種類（腰の強さ）による分離搬送の状態を示す図である。It is a figure which shows the state of the separation conveyance by the transfer nip width | variety and the kind (waist strength) of paper. 画像形成装置の回路構成の一部を示すブロック線図である。2 is a block diagram showing a part of the circuit configuration of the image forming apparatus. FIG. 紙の種類（腰の強さ）によってレジストローラにかけられる圧力を示す図である。It is a figure which shows the pressure applied to a registration roller by the kind (waist strength) of paper.

符号の説明Explanation of symbols

１ 感光体ドラム
２ 転写装置
３ 転写ベルト
４ 駆動ローラ
５ 従動ローラ
１０ レジストローラ
１１ 転写接離カム
１２ 押し上げレバー
３０ メイン制御部
３１ CPU
３７ 圧力センサ
３９ オペレーションパネル DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Transfer device 3 Transfer belt 4 Drive roller 5 Drive roller 10 Registration roller 11 Transfer contact / separation cam 12 Push-up lever 30 Main control unit 31 CPU
37 Pressure sensor 39 Operation panel

Claims (9)

像担持体上に担持されたトナー像を転写材に当接させて転写する転写方法において、
前記転写材の紙種データを紙種検知手段から得て、この紙種データに基づいて転写時の前記転写材と前記像担持体との当接条件を可変すること特徴とした転写方法。 In a transfer method for transferring a toner image carried on an image carrier in contact with a transfer material,
A transfer method characterized in that paper type data of the transfer material is obtained from paper type detection means, and a contact condition between the transfer material and the image carrier during transfer is varied based on the paper type data. 請求項１に記載の転写方法において、前記可変する当接条件が転写ニップ形成条件であり、前記紙種データにより転写材搬送方向における転写ニップ幅の長さを可変することを特徴とする転写方法。   The transfer method according to claim 1, wherein the variable contact condition is a transfer nip formation condition, and the length of the transfer nip width in the transfer material transport direction is changed according to the paper type data. . 請求項１または２に記載の転写方法において、前記転写材の先端が転写ニップ幅の中心に達するタイミングで前記当接条件を可変することを特徴とする転写方法。   3. The transfer method according to claim 1, wherein the contact condition is varied at a timing at which a leading edge of the transfer material reaches a center of a transfer nip width. 請求項１ないし３の何れかに記載の転写方法を用いる画像形成装置において、
トナー像を担持する像担持体と、該像担持体に当接し、転写材を搬送する転写搬送部材を有する転写装置と、前記転写搬送部材を前記像担持体に接離する方向へ移動して前記転写搬送手段の前記像担持体への当接圧を可変する当接圧可変手段と、前記転写材の紙種データを検知する紙種検知手段とを有することを特徴とする画像形成装置。 In the image forming apparatus using the transfer method according to claim 1,
An image carrier that carries a toner image; a transfer device that is in contact with the image carrier and that carries a transfer material for conveying a transfer material; and the transfer carrier member that is moved toward and away from the image carrier. An image forming apparatus comprising: a contact pressure varying unit configured to vary a contact pressure of the transfer conveying unit against the image carrier; and a paper type detecting unit configured to detect paper type data of the transfer material. 請求項４に記載の画像形成装置において、前記転写搬送部材が複数のローラに巻き掛けられた無端状の転写ベルトであることを特徴とする画像形成装置。   5. The image forming apparatus according to claim 4, wherein the transfer conveying member is an endless transfer belt wound around a plurality of rollers. 請求項４に記載の画像形成装置において、前記紙種検知手段が転写材搬送方向における転写領域の上流側に配置された一対の搬送ローラに設けられた圧力センサを有し、該圧力センサが前記搬送ローラにかかる圧力から転写材の厚みデータを検知することを特徴とする画像形成装置。   5. The image forming apparatus according to claim 4, wherein the paper type detection unit includes a pressure sensor provided on a pair of conveyance rollers disposed on the upstream side of the transfer region in the transfer material conveyance direction, and the pressure sensor An image forming apparatus, wherein thickness data of a transfer material is detected from pressure applied to a conveying roller. 請求項６に記載の画像形成装置において、前記一対の搬送ローラがレジストローラであることを特徴とする画像形成装置。   The image forming apparatus according to claim 6, wherein the pair of transport rollers are registration rollers. 請求項４または６に記載の画像形成装置において、前記紙種検知手段が入力された値から紙種を判定する制御装置であることを特徴とする画像形成装置。   7. The image forming apparatus according to claim 4, wherein the paper type detection unit is a control device that determines a paper type from an input value. 請求項８に記載の画像形成装置において、前記制御装置へ入力された値はオペレーションパネルから入力されたものであることを特徴とする画像形成装置。   9. The image forming apparatus according to claim 8, wherein the value input to the control device is input from an operation panel.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7606507B2 (en) 2006-07-18 2009-10-20 Konica Minolta Business Technologies, Inc. Image forming apparatus
US8219001B2 (en) * 2008-05-12 2012-07-10 Konica Minolta Business Technologies, Inc. Image forming apparatus provided with transfer and separation device
US8433220B2 (en) 2008-12-15 2013-04-30 Fuji Xerox Co., Ltd. Image forming apparatus having transfer member and control method for adjusting drive torque for the transfer member
JP2018072651A (en) * 2016-11-01 2018-05-10 コニカミノルタ株式会社 Image forming apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7606507B2 (en) 2006-07-18 2009-10-20 Konica Minolta Business Technologies, Inc. Image forming apparatus
US8219001B2 (en) * 2008-05-12 2012-07-10 Konica Minolta Business Technologies, Inc. Image forming apparatus provided with transfer and separation device
US8433220B2 (en) 2008-12-15 2013-04-30 Fuji Xerox Co., Ltd. Image forming apparatus having transfer member and control method for adjusting drive torque for the transfer member
JP2018072651A (en) * 2016-11-01 2018-05-10 コニカミノルタ株式会社 Image forming apparatus

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