JP4240801B2 - Non-fixing image receiving sheet - Google Patents

Description

【００４５】
上記表１において、本願発明を適用したサンプルシート、特にサンプルシートＳＰ４〜ＳＰ８のように、二酸化チタン微粒子の含有量を０．１〜２．０ｇとした場合には、導電性キャリヤ及び絶縁性キャリヤのいずれの場合でも、トナー画像の除去性（クリーニング性）はきわめて良好（◎）であった。
【００４６】
この理由は、シート表層２と磁気ブラシのキャリヤ４０との間の摺接により生じるシート表層（メディア）２の摩擦帯電を、二酸化チタンの微粒子により速やかに、かつ適量リークし、シート表層２に多量に帯電電荷するのを防止するからである。
【００４７】
なお、サンプルシートＳＰ１のように二酸化チタン微粒子を含有させていない場合は、導電性キャリヤではクリーニング性について一応良好な評価（○）を得られたが、絶縁性キャリヤの場合は評価が（×）であり、クリーニング後のトナー粒子の残存量が多かった。
【００４８】
このような効果は二酸化チタン微粒子以外にも、酸化亜鉛やアルミナ、炭酸カルシウム等で同様に確認された。またその添加量としても、上記表１のサンプルシートＳＰ４〜ＳＰ８と同様に、受像シート１平方メートル当たり０．１〜２ｇの範囲で極めて良好な結果を示した。
【００４９】
なお、二酸化チタンの含有量が２ｇを超えるとサンプルシートＳＰ９〜ＳＰ１１に示すように、シート表面の粗さが大きくなり、これらに影響されてトナーが取れにくい傾向が見られる。
【００５０】
【本願発明の別の実施の形態】
（１）図２に示す乾式のシートクリーニング装置（画像除去装置）２０の代わりに、図６に示すように、受像シートに液体を付与することで、受像シートの凹部のトナーを除去し、該シートを再使用可能な状態に再生する画像除去装置２１０に、本願発明による非定着式受像シートを適用することも可能である。以下、図６の画像除去装置２１０を説明する。
【００５１】
▲１▼ 画像除去装置の概略構成
画像除去装置２１０は、概略、この装置２１０で再生する受像シートＳを収容し供給するシート供給部２１２と、シート供給部２１２から送り出された受像シートＳに液体を付与して該受像シートＳを濡らす浸漬部２１４と、液体の付与された受像シートＳからトナーを除去するトナー除去部２１６と、トナーが除去された受像シートＳに液体をスプレーして該受像シートＳ上に残留しているトナーなどの異物を除去するリンス部２１８と、トナーが除去された受像シートＳの表面に付着した液体を除去する液体除去部２２０と、液体を除去した受像シートＳを再利用可能な状態まで乾燥する乾燥部２２２と、乾燥した受像シートＳを排出し収容するシート排出部２２４とを有する。
【００５２】
▲２▼ シート供給部
シート供給部２１２は、受像シートＳを収容する供給トレイ２２６を有する。シート供給部２１２はまた、供給トレイ２２６に積層して収容されている複数の受像シートＳから最上シートのみを送り出すための捌き機構２２８と、捌き機構２２８によって下層のシートから分離された最上シートをシート搬送経路２３０に沿って送り出す送り出し機構２３２を有する。本実施形態では、捌き機構２２８として、最上シートに接触するピックアップローラと該ピックアップローラの外周面に接触する捌きパッドとを有する捌き装置を利用しているが、他の形態の捌き装置を利用してもよい。また、送り出し機構２３２としては、通常、駆動系に連結された第１の軸とこれに平行に配置された第２の軸とを有し、これらの軸に所定の間隔をあけて複数のローラ（例えば、ゴムローラ）を取り付け、一方の軸に取り付けたローラと他方の軸に取り付けたローラとでシートを挟持して搬送する、従来から複写機やプリンタの用紙搬送装置として利用されているローラ搬送装置が利用される。
【００５３】
▲３▼ 浸漬部
浸漬部２１４は、クリーニング液（液体）２３４を収容する容器２３６を有する。クリーニング液２３４としては、水が利用される。なお、受像シートＳに付着しているトナーを除去し易くするために、界面活性剤を約０．０１％（＝界面活性剤の重量／水の重量）添加してもよい。また、必要に応じて他の材料をクリーニング液２３４に添加してもよい。
【００５４】
容器２３６の内部空間は、越流壁２３８によって、受像シートＳを浸漬するための浸漬槽２４０と、この浸漬槽２４０から越流したクリーニング液２３４を収容する越流槽２４２とに分断されている。容器２３６にはまた、浸漬槽２４０から越流壁２３８を越流して越流槽２４２に流れ込んだクリーニング液２３４を再び浸漬槽２４０に送り込むとともに越流槽２４２から浸漬槽２４０にクリーニング液２３４を送る過程で該クリーニング液２３４に含まれる異物（例えば、トナー）を回収する液体循環部２４４が付設されている。
【００５５】
液体循環部２４４は液体循環路２４８を有する。液体循環路２４８は、一端が越流槽２４２に接続され、他端が浸漬槽２４０の上方に位置している。したがって、越流槽２４２に溜まったクリーニング液２３４は、浸漬槽２４０に液面上から補給される。また、液体循環路２４８は、この液体循環路２４８に沿ってクリーニング液２３４を強制循環するためのポンプ２５０と、クリーニング液２３４に含まれる異物を除去するフィルタ部２５２を有する。
【００５６】
越流槽２４２の液面高さを一定にするために、液面高さを計測し、越流槽２４２内の水位が所定以下になると図示しない予備タンクから浸漬槽２４０にクリーニング液２３４が補充されるようにしてもよい。
【００５７】
容器２３６の浸漬槽２４０には、シート搬送経路２３０に沿って、シート供給部２１２から送られてきた受像シートＳを浸漬槽２４０内のクリーニング液２３４中で搬送するために、複数の搬送機構２５６と、これら複数の搬送機構２５６の間で受像シートＳをガイドするガイド部材（図示せず）とを有する。搬送機構２５６は、上述したローラ搬送装置が用いられる。ガイド部材としては、シート搬送経路２３０を挟み、所定の間隔をあけて対向する一対のガイド板（クリーニング液２３４が出入りできる複数の開口部を有する板）又はガイドワイヤ（シート搬送方向に伸び且つシート搬送方向と直交する方向に所定の間隔をあけて配置された複数のワイヤ）が好適に利用できる。
【００５８】
▲４▼ トナー除去部
トナー除去部２１６は、シート搬送経路２３０を挟んで対向する一対のブラシローラ２５８を有する。これらブラシローラ２５８は、駆動系に連結された軸と、この軸の外周にナイロン繊維の植毛された基布を巻き付けたものが利用され、シート搬送経路２３０に沿って搬送される受像シートＳの表面と裏面にそれぞれのブラシローラ２５８の毛が接触するように配置されている。また、ブラシローラ２５８の間を通過する受像シートＳの表面又は裏面に付着しているトナーに接触して該受像シートＳからトナーを除去するために、それぞれ図示しないモータに駆動連結されている。
【００５９】
なお、ブラシローラ２５８の周速度は、受像シートＳの搬送速度の数倍から数十倍に設定される。また、ブラシローラ２５８の回転方向について簡単に説明すると、受像シートＳの先端がブラシローラ２５８の対向部に進入するときブラシローラ２５８の毛先がシート搬送方向に移動し、受像シートＳの先端が対向部を通過した後は毛先がシート搬送方向と逆方向に移動するように、ブラシローラ２５８の駆動モータを制御することが好ましい。
【００６０】
なお、図６では、受像シートＳに接触して該受像シートＳからトナーを除去する部材としてブラシローラ２５８を用いているが、回転軸の周囲にスポンジ又は布等の柔らかい部材を取り付けたローラを利用することもできる。
【００６１】
▲５▼ リンス部
リンス部２１８は、一対のブラシローラ２５８の間を通過する又は通過した受像シートＳの表面と裏面にクリーニング液２３４を供給するために、シート搬送経路２３０を挟み且つブラシローラ２５８の上方に配置されたスプレーノズル２６０を有する。このスプレーノズル２６０は、上述した液体循環路２４８の他端に接続されており、この液体循環路２４８で浄化されたクリーニング液２３４が供給されるようにしてある。なお、本実施形態において、スプレーノズル２６０は、所定の間隔をあけて液体噴射孔を形成した管をその途中で１８０°折り返して形成されている。
【００６２】
なお、図に示すように、シート搬送経路の両側にブラシローラ２５８及びスプレーノズル２６０を設けてあるのは、供給トレイ２２６上に受像シートの凹凸面を下側又は上側にして配置しても画像除去が行われるようにするためである。
【００６３】
▲６▼ 液体除去部
液体除去部２２０は、シート搬送経路２３０を挟んで対向するとともに、このシート搬送経路２３０上で互いに接触する２つのローラからなる絞りローラ対２６２を有する。これら絞りローラ対２６２を構成する２つのローラの一方は図示しないモータに駆動連結されている。
【００６４】
▲７▼ 乾燥部
乾燥部２２２は、クリーニング液２３４が除去された受像シートＳを、画像形成装置で再利用できる状態まで乾燥するために、液体除去部２２０の下流側に配置される。乾燥部２２２として、本実施形態では、シート搬送経路２３０を挟んで対向するとともに、このシート搬送経路２３０上で互いに接触する２つのローラ２６４、２６６からなる。これらローラ２６４、２６６のうち、少なくとも一方のローラ２６６は内部に加熱源であるヒータ２６８を備えている。
【００６５】
なお、乾燥部２２２の乾燥手段として、上述したローラ型加熱器の代わりに、例えば、シートに対して常温の空気を吹付けるだけの送風機や、温風を吹出すことのできるヒータ内蔵型送風機を用いてもよい。さらに除湿機によって乾燥させた空気を吹付ける形態のものであってもよい。
【００６６】
▲８▼ シート排出部
シート排出部２２４は、乾燥部２２２で乾燥された受像シートＳを積層して収容する排出トレイ２７０を有する。
【００６７】
▲９▼ シート再生処理
以上の構成を有する画像除去装置２１０の動作を説明する。具体的に、再生すべき受像シートＳは供給トレイ２２６に積層して収容される。この状態で装置２１０が起動すると、供給トレイ２２６に収容された複数の受像シートＳは、捌き機構２２８によって最上シートから順次送り出され、送り出し機構２３２によって浸漬部２１４に供給される。
【００６８】
浸漬部２１４に供給された受像シートＳは、ガイド部材にガイドされながら搬送機構２５６によって搬送され、浸漬槽２４０内のクリーニング液２３４に所定時間浸漬され、受像シートＳのシート表層の凹部にクリーニング液２３４が浸透する。これにより、受像シートＳの表面の凹部の中に付着しているトナーと表面との接着力が失われ、トナーは機械的な力を与えるだけで分離可能な状態になる。浸漬槽２４０のクリーニング液２３４から排出された受像シートＳは、その表面と裏面が一対のブラシローラ２５８の摺擦力を受け、これら表面又は裏面に付着しているトナーが除去される。このとき、受像シートＳの表面と裏面にはそれぞれスプレーノズル２６０からクリーニング液２３４が噴射され、ブラシローラ２５８の対向部を通過したシート部分に付着しているトナーが洗い流される。また、ブラシローラ２５８に付着したトナーが浸漬槽２４０に洗い落とされる。
【００６９】
浸漬槽２４０に落下したトナー、また浸漬槽２４０の中を受像シートＳが搬送される過程で該受像シートＳから分離したトナーは、越流壁２３８を越えて浸漬槽２４０から越流槽２４２に流れるクリーニング液２３４と共に越流槽２４２に流れ込む。越流槽２４２のクリーニング液２３４に含まれるトナーは、液体循環路２４８内をポンプ２５０によって送られ、フィルタ部２５２によって除去される。トナーが除去されたクリーニング２３４は、スプレーノズル２６０から受像シートＳの表面と裏面、及びブラシローラ２５８に噴射される。
【００７０】
トナーが除去された受像シートＳは、液体除去部２２０の絞りローラ対２６２によって挟圧され、表面上のクリーニング液２３４が除去される。続いて、受像シートＳは乾燥部２２２に送られて乾燥された後、シート排出部２２４の排出トレイ２７０上に排出される。
【００７１】
【発明の効果】
以上説明したように本願発明は、
（１）トナー粒子が除去可能に付着される非定着式受像シートを採用しているので、受像シートの再利用ができ、紙消費量を削減できると共に、定着式のようなエネルギー及び消耗品が不要になり、また、受像シートから回収したトナーを再利用でき、ランニングコストの低減が可能になる。
【００７２】
（２）受像シートの表面に、トナー粒子を受容する多数の凹部とトナー粒子を保護する多数の凸部が形成されているので、凹部内にトナー粒子を機械的に確実に保持し、かつ、多数の凸部により上記機械的な保持を強固にすると共に、凸部がスペーサとしての役目を果たすことにより、上方からの異物（指あるいは他のシート裏面）の接触を確実に防ぎ、機械的な保持性を向上させることができる。
【００７３】
（３）熱硬化性あるいは熱可塑性のシート表層に、二酸化チタン等の金属酸化物の微粒子又はシリカ、炭酸カルシウムの微粒子を含有させているので、適度な静電引力によるトナー粒子保持力を維持しながらも、磁気ブラシによるクリーニング時に、摩擦帯電による過電荷をリークして、良好なクリーニング性を確保することができる。
【００７４】
（４）特に、前記のようにシート表層２に多数の凹部と多数の凸部を形成することにより、トナー粒子の機械的な保持性を向上させることができる一方、それら凹部及び凸部が磁気ブラシによるクリーニングに邪魔になり、かつ、摩擦帯電が生じ易くなっている場合でも、過電荷を適量逃がし、確実にクリーニング性を向上させることができる。
【００７５】
（５）二酸化チタン等金属酸化物の微粒子の含有量を受像シート１平方メートル当たり０．１〜２ｇとすると、そのクリーニング性の効果は一層顕著になる。
【図面の簡単な説明】
【図１】 本願発明を適用した非定着式受像シートの縦断面部分拡大斜視図である。
【図２】 画像形成装置の簡略側面図である。
【図３】 画像形成装置の転写部の拡大縦断面図である。
【図４】 凸条部クリーニング装置の拡大縦断面図である。
【図５】 クリーニング装置（画像除去装置）の拡大縦断面図である。
【図６】 湿式のクリーニング装置（画像除去装置）の簡略側面図である。
【符号の説明】
２ シート表層
３ シート芯層
５ 溝状凹部
６ 凸部（凸条部）
１０ トナー粒子
２０ シートクリーニング装置
２５ 磁気ブラシローラ
４０ 磁性キャリヤ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-fixing image-receiving sheet in which toner particles are removably attached to the surface of the sheet.
[0002]
[Prior art]
[Fixed image receiving sheet]
Currently, printers used for output from a personal computer generally use an electrophotographic system in which toner particles are heated and fixed on an image receiving sheet made of paper, plastic, or the like, or ink receiving sheet. A typical example is an ink-jet system in which drying is fixed on the top.
[0003]
In each of the fixing methods described above, printing time is required, and consumables such as electricity bills and ink are required, which increases running costs. In addition, due to the recent trend toward reducing environmental impact, printer energy and paper consumption are required to be reduced.
[0004]
On the other hand, paper output by a printer or the like is temporarily necessary, but at present, the paper is no longer needed and is often discarded.
[0005]
[Non-fixing image receiving sheet]
In contrast to the above method, a method of reusing transfer paper is also known. For example, as a method for separating the toner from the transfer paper, a method of melting and peeling the solidified toner by passing the transfer paper between a pair of heat rollers, and a method of deinking using an aqueous solution such as a surfactant are known. It has been.
[0006]
However, a large amount of energy is required for heating and removing moisture that permeates, and the removed toner is melted and solidified and cannot be reused.
[0007]
Japanese Patent Laid-Open No. 6-43682 discloses a method for solving such a problem, in which minute protrusions are dispersedly formed on the surface of the image receiving sheet, and a toner image is transferred onto the surface of the image receiving sheet having a large number of minute protrusions. It is proposed that an image is formed by fixing with pressure, and then the toner is removed from the image receiving sheet and the image receiving sheet and toner are reused.
[0008]
As a means for removing the toner from the image receiving sheet, a mechanical method such as a brush is widely used. However, the mechanical method alone causes contamination on the non-fixing type image receiving sheet having a large number of minute protrusions as described above. It was difficult to completely remove the toner so as not to remain, and complete reproduction was difficult. That is, even if mechanically cleaned with a brush, toner particles remain around the base of the protrusion, and if there are minute recesses, the toner particles fitted in the recesses cannot be removed.
[0009]
In addition to such mechanical toner removing means, there is means for electrostatically absorbing and removing toner using a magnetic brush. That is, this is a method in which a magnetic brush for collecting toner is charged to a polarity opposite to the charging polarity of the toner, the toner is attracted to the magnetic brush by electrostatic attraction, and the toner is removed from the image receiving sheet surface.
[0010]
[Problems to be solved by the invention]
However, even when cleaning is performed using electrostatic attraction using a magnetic brush, frictional charging occurs on the sheet surface layer (or toner) due to the sliding contact between the magnetic brush carrier and the sheet surface layer (media) during the cleaning operation. This increases the amount of charge on the surface layer of the sheet.
[0011]
When a conductive carrier is provided as a magnetic brush carrier, the increased charged charge can be released to some extent from the conductive carrier. However, when an insulating resin carrier is provided, There is no path for charge leakage, and the amount of charge on the surface of the sheet increases rapidly, which increases the force for adsorbing toner, and on the contrary, the toner particle removal performance decreases.
[0012]
Further, in the non-fixing type image receiving sheet described in JP-A-6-43682, the minute protrusions are simply formed in a dispersed manner, so that the toner remains attached to the minute protrusions of the image receiving sheet, and after the image formation. An image receiving sheet may be handled. Although it is fixed to the protrusions by pressure treatment, the toner is fixed to such an extent that it can be mechanically removed from the image-receiving sheet, and the fingers and the back of the sheet are soiled by touching or rubbing with fingers. Sometimes it ends up.
[0013]
Furthermore, since the minute protrusions formed on the image receiving sheet are formed in isolated dot shapes, they are easily bent or deformed when subjected to an external force, so that an object can easily enter between the protrusions and the image is disturbed. The toner image cannot be sufficiently protected.
[0014]
OBJECT OF THE INVENTION
SUMMARY OF THE INVENTION An object of the present invention is to realize an image receiving sheet that can be used repeatedly, and to improve cleaning properties (toner removal properties) as well as toner particle retention properties.
[0015]
[Technical means for solving the problems]
In order to achieve the above object, according to the first aspect of the present invention, in the non-fixing type image receiving sheet to which the toner particles are removably attached, the surface of the image receiving sheet is provided with a plurality of recesses for receiving the toner particles and the toner particles. The surface of the image receiving sheet that forms a large number of convex portions to be protected and forms the concave portions and the convex portions is formed of a polymer compound containing fine particles of metal oxide, and the content of the fine particles of metal oxide is It is characterized by 0.1 to 2 g per square meter of image receiving sheet .
[0016]
According to a second aspect of the present invention, in the non-fixing image-receiving sheet according to the first aspect, the fine particles of metal oxide include fine particles of zinc oxide, titanium dioxide or alumina.
[0017]
The invention described in claim 3 is the non-fixing image-receiving sheet according to claim 1 , characterized in that it contains fine particles of calcium carbonate or silica instead of the metal oxide.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
[Structure of non-fixing image receiving sheet]
FIG. 1 is an enlarged partial perspective view of a longitudinal section of a non-fixing image-receiving sheet S to which the present invention is applied. The cross-sectional structure of the image-receiving sheet S is a two-layer structure including a sheet surface layer (media) 2 and a sheet core layer 3. ing. The surface of the sheet surface layer 2 is an uneven surface on which a large number of concave portions 5 and convex portions 6 are formed.
[0020]
The concave portion 5 is formed in a continuous groove shape, and the convex portion 6 is continuous in a ridge shape along the groove-shaped concave portion 5 and is formed as a so-called convex strip portion.
[0021]
The groove recess 5 is regularly provided in parallel with, for example, the same width W1 in order to receive the toner 10. It is desirable that the width W1 of each recess 5 has a width that is twice or more the average particle diameter of the toner 10. For example, with respect to the average particle diameter of 2 to 30 μm of the toner 10, the width W1 of each groove-like recess 5 is preferably 20 μm to 500 μm, and the depth D (projection height H) is 20 μm to 100 μm. Preferably there is. The width W <b> 2 of the convex portion 6 is preferably less than or equal to ½ or less than ½ of the width W <b> 1 of the groove-like recess 5.
[0022]
The image receiving sheet S can be formed of various materials such as paper, synthetic resin (polyester, polyethylene terephthalate, polyolefin (polypropylene, polyethylene, etc.), polyimide, polyamide, etc.), and combinations thereof.
[0023]
The specific material and structure of each of the layers 2 and 3 will be described. The sheet core layer 3 is made of plain paper used in a copying machine or the like, and the sheet surface layer 2 is a polymer compound such as polyethylene, acrylic, This sheet surface layer 2 is made of a thermoplastic resin such as polyester, and has a semiconductor characteristic such as fine particles of metal oxide such as titanium dioxide, zinc oxide or alumina or silica, clay or talc according to the present invention. The fine particles of the inorganic compound are uniformly contained. The content of these fine particles such as titanium dioxide is preferably 0.1 to 2 g per square meter of the image receiving sheet. Note that a thermosetting resin can also be used as the sheet surface layer 2.
[0024]
As shown in FIG. 1, the concave portion 5 has a continuous groove shape, and the convex portion 6 has a ridge-shaped convex portion 6 along the continuous groove-shaped concave portion 5, so that the convex portion 6 has a width W 1 and an upper space of the concave portion 5. The toner attached to a predetermined position on the bottom surface of the groove recess 5 is mechanically stably held, and even if the image sheets on which the images have been formed are stacked, the back surface of the upper image sheet is the toner. In addition, even if the surface of the image sheet is touched with the hand, the convex stripes 6 protect the toner particles, so that the hand is not stained or the image receiving sheet surface is not stained.
[0025]
[Method for producing non-fixing image-receiving sheet]
As shown in FIG. 1, as a method for forming the uneven sheet surface layer 2 containing metal oxide fine particles in a laminated form on the sheet core layer 3, a synthetic resin (for example, a thermoplastic resin such as polyethylene, acrylic, or polyester) is used. ) And a surface layer material layer obtained by kneading fine particles of titanium oxide, zinc oxide, silica, alumina, clay, talc, etc., on the sheet core layer 3 made of paper or the like, and forming a predetermined continuous groove-like recess 5 An uneven shape is formed by a mold (for example, a master roller) on which a pattern that can be formed is formed. It may be performed by casting a resin into a mold.
[0026]
As another method, a polyethylene sheet is layered on the paper sheet core layer 2, a metal oxide powder such as titanium dioxide is uniformly sprinkled on the surface, and a mold made of silicone rubber is layered thereon. The mold is transferred by melting the polyethylene sheet by placing the material on the heater and raising the temperature. At the same time, a sheet surface layer (media) 2 containing fine particles such as titanium dioxide on its surface can be formed on the paper sheet core layer 3.
[0027]
[Image forming apparatus]
An image forming apparatus for forming an image on a non-fixing type image receiving sheet according to the present invention will be described.
[0028]
FIG. 2 shows an example of an image forming apparatus. A sheet cleaning device (toner removing device) 20 is disposed on the conveyance start end side (left side in FIG. 2) of the transfer device 21, and a protrusion cleaning device (on the conveyance end side) A ridge toner removing device) 22 is disposed.
[0029]
The sheet cleaning device 20 includes a magnetic brush roller 25 and a counter roller 26. In FIG. 5, a magnetic brush for development is used as the magnetic brush roller 25, and the carrier 40 constituting the brush portion of the brush roller 25 is a mixture of a conductive carrier made of iron powder or the like and resin and magnetite. A resin carrier is used. A bias having a polarity opposite to the charging electrode property (negative polarity) of the toner particles 10 is applied to the magnetic brush roller 25, and the opposing roller 26 is grounded.
[0030]
The transfer device 21 shown in FIG. 2 includes a drum-shaped photosensitive member 27 and a transfer roller 28 facing the drum-shaped photosensitive member 27. Around the photosensitive member 27, a transfer unit 30 that is in contact with the transfer roller 28 extends in the drum rotation direction R side. In order, a toner wiping unit (scraping unit) 31, an image charging unit 32, an exposure unit 33, and a developing unit 34 are arranged. A bias that attracts toner particles is applied to the transfer roller 28. The protrusion cleaning device 22 includes a charging roller 35 and a counter roller 36, and a toner wiping portion 37 is disposed on the charging roller 35.
[0031]
[Image forming method]
An image forming method using the image forming apparatus of FIG. 2 will be described.
(1) The transfer device 21 uniformly charges the surface of the photosensitive member 27 to about −900 V in the image charging unit 32, performs exposure according to the image data in the exposure unit 33, and electrostatic latent image on the surface of the photosensitive member 27. Form an image. Of the surface of the photoreceptor 27, the exposed portion is attenuated to about -100V, and the unexposed portion is maintained at about -900V. Thereafter, toner particles (negative polarity) are attached to the photoreceptor 27 in accordance with the electrostatic latent image in the developing unit 34.
[0032]
(2) When the image receiving sheet S is reused, the toner particles in the groove recesses 5 are once removed by the cleaning device 20 as will be described later. It is cleaned and conveyed to the transfer unit 30 of the transfer device 21.
[0033]
(3) In the transfer unit 30 of the transfer device 21, the toner particles of the electrostatic latent image attached to the photoconductor 27 are transferred. At this time, as the bias applied to the transfer roller 28, for example, about +1 kV is applied.
[0034]
(4) FIG. 3 is an enlarged view of the transfer portion 30, and most of the toner particles 10 adhering to the surface of the photosensitive member 27 adhere to the bottom surface of the groove recess 5, but a part thereof is a protrusion 6 also adheres. At the time of transfer, the protrusion 6 serves as a spacer between the photoreceptor 27 and the bottom surface of the groove-shaped recess 5 to prevent the bottom surface of the groove recess 5 and the photoreceptor 27 from being too close, An appropriate electric field distance can be secured and good transferability can be exhibited.
[0035]
(5) The image receiving sheet S to which the toner image has been transferred is conveyed to the convex portion cleaning device 22 of FIG. 2, and the convex portion is formed by the electrostatic force of the charging roller (positive charge) 35 as shown in FIG. The toner particles 10 attached to 6 are collected. At this time, a bias of about +300 V is applied to the charging roller 35, and the opposing roller 36 is grounded.
[0036]
[Cleaning method (Toner removal method)]
When the image-receiving sheet S on which an image has been formed is used again, the toner particles conveyed to the sheet cleaning device 20 in FIG. 2 and attached to the recess 5 are collected by the magnetic brush roller 25 using electrostatic attraction. . At this time, a bias of about +1 kV having a polarity opposite to the toner particle charging polarity is applied to the magnetic brush roller 25. The opposing roller 26 is grounded.
[0037]
FIG. 5 is an enlarged vertical cross-sectional view of the main part of the sheet cleaning device 20, and the toner particles 10 on the image receiving sheet S are negatively charged and attached to the sheet surface layer 2. At the same time, the carrier 40 mechanically removes the toner particles 10 because the carrier 40 is positively charged, and electrostatically removes the toner particles from the surface of the image receiving sheet.
[0038]
During the cleaning operation, the carrier 40 and the sheet surface layer 2 are in sliding contact with each other, whereby abrasion charge is generated in the resinous sheet surface layer 2 and the charge amount on the surface of the image receiving sheet is increased. Although the adsorptive power tends to be enhanced, since the fine particles of metal oxide such as titanium dioxide are present in the resinous sheet surface layer 2, the increased charge amount can be appropriately leaked. Thereby, so-called charge-up in the sheet surface layer 2 can be prevented, and electrostatic attraction of the toner particles 10 by the carrier 40 can be maintained well. That is, the cleaning operation using the magnetic brush can be kept in a good state.
[0039]
【Example】
Table 1 below shows the production of 11 types of sample sheets SPn of the non-fixing image-receiving sheet S as shown in FIG. 1, and the evaluation of cleaning properties is compared. The sample sheets SP2 to SP11 contain titanium dioxide fine particles. The sample sheets are different in content, and the remaining one sample sheet SP1 does not contain titanium dioxide fine particles. That is, after the toner images were formed on the sample sheets SP1 to SP11, cleaning was performed by the sheet cleaning device 20 having the magnetic brush roller 25 shown in FIG. 2, and the cleaning properties were compared when the toner images were removed. Is.
[0040]
As a specific manufacturing method of sample sheets SP2 to SP11 containing titanium dioxide, a thermoplastic resin (high density polyethylene) is uniformly applied on the paper sheet core layer 3, and then titanium dioxide ( Wako Pure Chemical Industries, Ltd. (titanium (IV) rutile type) fine particles are uniformly sprinkled, and the shape forming molds are stacked and hot pressed (120 ° C, 30 minutes, 10 kg / cm ² ), then cooled and separated. The surface shape was transferred. The uneven shape at this time was a concave portion width of 200 μm, a convex portion width of 10 μm, and a height of 50 μm. When the surface was observed, it was confirmed that titanium dioxide was embedded in the resin layer on one side. In addition, about the sample sheet SP1 which does not contain titanium dioxide, the sprinkling process of titanium dioxide microparticles | fine-particles was abbreviate | omitted among the said manufacturing processes.
[0041]
In addition, instead of applying the resin, a high-density polyethylene sheet film (Toyobo Co., Ltd., 30 μM) is layered on plain paper, similarly sprinkled with titanium dioxide fine particles, and further overlaid with a mold for shape creation, and then hot pressed (120 ° C., 30 minutes) 10 kg / cm ² ), and then cooled and separated, and the surface shape can be transferred to form.
[0042]
As the binder, a polymer material such as polyethylene, polypropylene, styrene acrylic, and polyester was used.
[0043]
As the magnetic brush carrier 40 used for the magnetic brush roller 25 of the sheet cleaning apparatus 20 of FIG. 2, two types of a conductive carrier made of iron powder and an insulating carrier mixed with resin and magnetite were used.
[0044]
[Evaluation of cleaning properties]
Each of the image-formed sample sheets SP1 to SP11 is cleaned by the sheet cleaning device 20 shown in FIG. 2 provided with the conductive carrier or the insulating carrier as described above, and the afterimage of the sample sheet is visually evaluated. Those with (◎) were good, those with no afterimage were good (○), and others were with (×).
[Table 1]

[0045]
In Table 1 above, when the content of titanium dioxide fine particles is 0.1 to 2.0 g as in sample sheets to which the present invention is applied, particularly sample sheets SP4 to SP8, conductive carriers and insulating carriers. In any of the cases, the removability (cleanability) of the toner image was very good (）).
[0046]
The reason for this is that the surface charge of the sheet surface layer (media) 2 caused by the sliding contact between the sheet surface layer 2 and the carrier 40 of the magnetic brush is quickly and appropriately leaked by the fine particles of titanium dioxide, and the sheet surface layer 2 has a large amount. This is because it prevents the electric charges from being charged.
[0047]
When the titanium dioxide fine particles were not contained as in the sample sheet SP1, a good evaluation (◯) was obtained for the cleaning property with the conductive carrier, but the evaluation was (×) with the insulating carrier. The amount of toner particles remaining after cleaning was large.
[0048]
Such an effect was similarly confirmed with zinc oxide, alumina, calcium carbonate and the like in addition to the titanium dioxide fine particles. Moreover, also as the addition amount, the very favorable result was shown in the range of 0.1-2g per square meter of image receiving sheet similarly to sample sheet | seat SP4-SP8 of the said Table 1.
[0049]
When the content of titanium dioxide exceeds 2 g, as shown in sample sheets SP9 to SP11, the roughness of the sheet surface becomes large, and it tends to be difficult to remove toner due to these effects.
[0050]
[Another embodiment of the present invention]
(1) Instead of the dry sheet cleaning device (image removing device) 20 shown in FIG. 2, as shown in FIG. 6, by applying a liquid to the image receiving sheet, the toner in the recesses of the image receiving sheet is removed, It is also possible to apply the non-fixing image receiving sheet according to the present invention to the image removing apparatus 210 that reproduces a sheet in a reusable state. Hereinafter, the image removing apparatus 210 of FIG. 6 will be described.
[0051]
(1) Schematic configuration of image removing apparatus The image removing apparatus 210 is roughly configured to store and supply an image receiving sheet S reproduced by the apparatus 210, and to supply liquid to the image receiving sheet S sent out from the sheet supplying section 212. The image receiving sheet S is soaked to wet the image receiving sheet S, the toner removing unit 216 removes the toner from the liquid image receiving sheet S, and the image receiving sheet S from which the toner has been removed is sprayed with liquid. A rinsing unit 218 for removing foreign matters such as toner remaining on the sheet S, a liquid removing unit 220 for removing liquid adhering to the surface of the image receiving sheet S from which the toner has been removed, and an image receiving sheet S from which liquid has been removed. Are dried to a reusable state, and a sheet discharge unit 224 that discharges and stores the dried image-receiving sheet S.
[0052]
(2) Sheet Supply Unit The sheet supply unit 212 includes a supply tray 226 for storing the image receiving sheet S. The sheet supply unit 212 also includes a separation mechanism 228 for sending out only the uppermost sheet from the plurality of image receiving sheets S accommodated in the supply tray 226, and the uppermost sheet separated from the lower layer sheet by the separation mechanism 228. A delivery mechanism 232 that delivers the sheet along the sheet conveyance path 230 is provided. In the present embodiment, a whirling device having a pick-up roller that contacts the uppermost sheet and a whirling pad that touches the outer peripheral surface of the pick-up roller is used as the whirling mechanism 228, but a whirling device of another form is used. May be. The feed mechanism 232 usually has a first shaft connected to the drive system and a second shaft arranged in parallel to the first shaft, and a plurality of rollers with a predetermined interval between these shafts. (For example, a rubber roller) is attached, and the sheet is nipped and conveyed by a roller attached to one shaft and a roller attached to the other shaft, and has been conventionally used as a paper conveyance device for copying machines and printers. A device is used.
[0053]
(3) Immersion part The immersion part 214 has a container 236 for storing a cleaning liquid (liquid) 234. Water is used as the cleaning liquid 234. In order to easily remove the toner adhering to the image receiving sheet S, a surfactant may be added in an amount of about 0.01% (= surfactant weight / water weight). Further, other materials may be added to the cleaning liquid 234 as necessary.
[0054]
The internal space of the container 236 is divided by the overflow wall 238 into an immersion tank 240 for immersing the image receiving sheet S and an overflow tank 242 for storing the cleaning liquid 234 that has overflowed from the immersion tank 240. . Further, the cleaning liquid 234 that has flowed from the immersion tank 240 to the overflow tank 242 through the overflow wall 238 is sent again to the immersion tank 240 and the cleaning liquid 234 is sent from the overflow tank 242 to the immersion tank 240. A liquid circulation unit 244 for collecting foreign substances (for example, toner) contained in the cleaning liquid 234 in the process is attached.
[0055]
The liquid circulation unit 244 has a liquid circulation path 248. The liquid circulation path 248 has one end connected to the overflow tank 242 and the other end positioned above the immersion tank 240. Therefore, the cleaning liquid 234 accumulated in the overflow tank 242 is replenished to the immersion tank 240 from above the liquid surface. Further, the liquid circulation path 248 includes a pump 250 for forcibly circulating the cleaning liquid 234 along the liquid circulation path 248 and a filter unit 252 for removing foreign substances contained in the cleaning liquid 234.
[0056]
In order to make the liquid level height of the overflow tank 242 constant, the liquid level height is measured, and when the water level in the overflow tank 242 falls below a predetermined level, the cleaning liquid 234 is replenished from the reserve tank (not shown) to the immersion tank 240. You may be made to do.
[0057]
In order to convey the image receiving sheet S sent from the sheet supply unit 212 in the cleaning liquid 234 in the immersion tank 240 along the sheet conveyance path 230, a plurality of conveyance mechanisms 256 are provided in the immersion tank 240 of the container 236. And a guide member (not shown) for guiding the image receiving sheet S between the plurality of transport mechanisms 256. As the transport mechanism 256, the above-described roller transport device is used. As the guide member, a pair of guide plates (plates having a plurality of openings through which the cleaning liquid 234 can enter and exit) or a guide wire (a sheet extending in the sheet conveyance direction and sandwiching the sheet conveyance path 230 with a predetermined interval therebetween) A plurality of wires arranged at predetermined intervals in a direction orthogonal to the transport direction can be suitably used.
[0058]
(4) Toner Removal Unit The toner removal unit 216 has a pair of brush rollers 258 facing each other with the sheet conveyance path 230 interposed therebetween. These brush rollers 258 use a shaft connected to a drive system and a base fabric in which nylon fibers are implanted around the shaft, and the image receiving sheet S conveyed along the sheet conveying path 230 is used. It arrange | positions so that the hair of each brush roller 258 may contact a surface and a back surface. In addition, in order to remove the toner from the image receiving sheet S in contact with the toner adhering to the front surface or the back surface of the image receiving sheet S passing between the brush rollers 258, each is connected to a motor (not shown).
[0059]
The peripheral speed of the brush roller 258 is set to several to several tens of times the conveying speed of the image receiving sheet S. The rotation direction of the brush roller 258 will be briefly described. When the leading edge of the image receiving sheet S enters the opposite portion of the brush roller 258, the hair tip of the brush roller 258 moves in the sheet conveying direction, and the leading edge of the image receiving sheet S is moved. It is preferable to control the drive motor of the brush roller 258 so that the hair ends move in the direction opposite to the sheet conveying direction after passing through the facing portion.
[0060]
In FIG. 6, the brush roller 258 is used as a member that contacts the image receiving sheet S and removes the toner from the image receiving sheet S. However, a roller having a soft member such as sponge or cloth around the rotation shaft is used. It can also be used.
[0061]
(5) Rinsing section The rinsing section 218 sandwiches the sheet conveying path 230 and supplies the brush roller 258 so as to supply the cleaning liquid 234 to the front and back surfaces of the image receiving sheet S that has passed between or passed between the pair of brush rollers 258. Has a spray nozzle 260 disposed above. The spray nozzle 260 is connected to the other end of the liquid circulation path 248 described above, and the cleaning liquid 234 purified by the liquid circulation path 248 is supplied thereto. In the present embodiment, the spray nozzle 260 is formed by folding back a pipe formed with liquid ejection holes at a predetermined interval by 180 ° in the middle.
[0062]
As shown in the figure, the brush roller 258 and the spray nozzle 260 are provided on both sides of the sheet conveyance path because the image receiving sheet is arranged on the supply tray 226 with the uneven surface on the lower side or the upper side. This is because removal is performed.
[0063]
(6) Liquid Remover The liquid remover 220 has a squeezing roller pair 262 composed of two rollers that are opposed to each other with the sheet conveying path 230 in between and in contact with each other on the sheet conveying path 230. One of the two rollers constituting the diaphragm roller pair 262 is drivingly connected to a motor (not shown).
[0064]
(7) The drying unit drying unit 222 is disposed on the downstream side of the liquid removing unit 220 in order to dry the image receiving sheet S from which the cleaning liquid 234 has been removed to a state where it can be reused in the image forming apparatus. In the present embodiment, the drying unit 222 includes two rollers 264 and 266 that are opposed to each other with the sheet conveyance path 230 interposed therebetween and are in contact with each other on the sheet conveyance path 230. Among these rollers 264 and 266, at least one of the rollers 266 includes a heater 268 serving as a heating source.
[0065]
In addition, as a drying means of the drying unit 222, instead of the above-described roller-type heater, for example, a blower that just blows room temperature air to the sheet, or a heater built-in blower that can blow warm air It may be used. Furthermore, the thing of the form which sprays the air dried with the dehumidifier may be sufficient.
[0066]
(8) Sheet Discharge Unit The sheet discharge unit 224 includes a discharge tray 270 that stores the image receiving sheets S dried by the drying unit 222 in a stacked manner.
[0067]
(9) The operation of the image removing apparatus 210 having the above configuration of the sheet reproduction process will be described. Specifically, the image receiving sheet S to be reproduced is stacked and accommodated on the supply tray 226. When the apparatus 210 is activated in this state, the plurality of image receiving sheets S accommodated in the supply tray 226 are sequentially fed from the uppermost sheet by the rolling mechanism 228 and are supplied to the immersion unit 214 by the feeding mechanism 232.
[0068]
The image receiving sheet S supplied to the dipping unit 214 is conveyed by the conveying mechanism 256 while being guided by the guide member, dipped in the cleaning liquid 234 in the dipping tank 240 for a predetermined time, and is cleaned in the concave portion of the sheet surface layer of the image receiving sheet S. 234 penetrates. As a result, the adhesive force between the toner adhering in the concave portion on the surface of the image receiving sheet S and the surface is lost, and the toner can be separated only by applying a mechanical force. The image receiving sheet S discharged from the cleaning liquid 234 of the dipping tank 240 receives the rubbing force of the pair of brush rollers 258 on the front and back surfaces, and the toner adhering to the front and back surfaces is removed. At this time, the cleaning liquid 234 is sprayed from the spray nozzle 260 to the front surface and the back surface of the image receiving sheet S, respectively, and the toner adhering to the sheet portion that has passed through the facing portion of the brush roller 258 is washed away. Further, the toner adhering to the brush roller 258 is washed away in the immersion tank 240.
[0069]
The toner dropped into the immersion tank 240 and the toner separated from the image receiving sheet S in the process of transporting the image receiving sheet S through the immersion tank 240 crosses the overflow wall 238 and enters the overflow tank 242 from the immersion tank 240. It flows into the overflow tank 242 together with the flowing cleaning liquid 234. The toner contained in the cleaning liquid 234 in the overflow tank 242 is sent through the liquid circulation path 248 by the pump 250 and removed by the filter unit 252. The cleaning 234 from which the toner has been removed is sprayed from the spray nozzle 260 onto the front and back surfaces of the image receiving sheet S and the brush roller 258.
[0070]
The image receiving sheet S from which the toner has been removed is pinched by the pair of squeezing rollers 262 of the liquid removing unit 220, and the cleaning liquid 234 on the surface is removed. Subsequently, the image receiving sheet S is sent to the drying unit 222 and dried, and then discharged onto the discharge tray 270 of the sheet discharge unit 224.
[0071]
【The invention's effect】
As described above, the present invention
(1) Since a non-fixing type image receiving sheet to which toner particles are removably attached is adopted, the image receiving sheet can be reused, paper consumption can be reduced, and energy and consumables such as a fixing type In addition, the toner collected from the image receiving sheet can be reused, and the running cost can be reduced.
[0072]
(2) Since the surface of the image receiving sheet has a large number of concave portions for receiving toner particles and a large number of convex portions for protecting the toner particles, the toner particles are mechanically securely held in the concave portions, and The above-mentioned mechanical holding is strengthened by a large number of convex portions, and the convex portions serve as spacers, thereby reliably preventing foreign matter (finger or other sheet back surface) from coming into contact with the mechanical portions. Retention can be improved.
[0073]
(3) Since the surface layer of the thermosetting or thermoplastic sheet contains fine particles of metal oxide such as titanium dioxide or fine particles of silica or calcium carbonate, the toner particle holding force by moderate electrostatic attraction is maintained. However, at the time of cleaning with the magnetic brush, it is possible to leak an overcharge due to frictional charging to ensure good cleaning properties.
[0074]
(4) In particular, by forming a large number of concave portions and a large number of convex portions on the sheet surface layer 2 as described above, the mechanical retention of toner particles can be improved, while the concave portions and the convex portions are magnetic. Even when it becomes an obstacle to cleaning with a brush and triboelectric charge is likely to occur, an appropriate amount of overcharge can be released and the cleaning performance can be improved reliably.
[0075]
(5) When the content of metal oxide fine particles such as titanium dioxide is 0.1 to 2 g per square meter of the image receiving sheet, the cleaning effect becomes more remarkable.
[Brief description of the drawings]
FIG. 1 is a partially enlarged perspective view of a longitudinal section of a non-fixing image receiving sheet to which the present invention is applied.
FIG. 2 is a simplified side view of the image forming apparatus.
FIG. 3 is an enlarged longitudinal sectional view of a transfer portion of the image forming apparatus.
FIG. 4 is an enlarged vertical sectional view of a ridge cleaning device.
FIG. 5 is an enlarged longitudinal sectional view of a cleaning device (image removing device).
FIG. 6 is a simplified side view of a wet cleaning device (image removal device).
[Explanation of symbols]
2 Sheet surface layer 3 Sheet core layer 5 Groove-shaped recess 6 Projection (projection strip)
10 toner particles 20 sheet cleaning device 25 magnetic brush roller 40 magnetic carrier

Claims (3)

In a non-fixing image receiving sheet to which toner particles are removably attached,
On the surface of the image receiving sheet, a large number of concave portions that receive toner particles and a large number of convex portions that protect the toner particles are formed.
The image receiving sheet surface forming the concave and convex portions is formed of a polymer compound containing metal oxide fine particles,
A non-fixing type image receiving sheet, wherein the content of the metal oxide fine particles is 0.1 to 2 g per square meter of the image receiving sheet. 2. The non-fixing image-receiving sheet according to claim 1 , wherein the metal oxide fine particles include fine particles of zinc oxide, titanium dioxide or alumina . 2. The non-fixing image-receiving sheet according to claim 1, comprising fine particles of calcium carbonate or silica instead of the metal oxide .

Images