JP2004238158A - Paper tray, automatic document feeding device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper tray capable of preventing breakage of a detection sensor caused by collision of document or paper against the detection sensor or damage of the document or the like and detecting the document securely and to provide an automatic document feeding device and an image forming apparatus using this paper tray. <P>SOLUTION: This paper tray is provided with a paper loading face 2 for loading the document and the document detection sensor provided on the paper loading face 2 to detect the document. The document detection sensor is the contact type detection sensor provided with a movable detection part having a protruding part 5 protruding substantially vertically for the paper loading face 2. The direction of installation of the protruding part 5 is not substantially parallel and substantially vertical for the direction of document conveyance. According to this document tray 11 provided on the paper loading face 2, the protruding part 5 in the document detection sensor or the document is not damaged to detect the document securely when loading the document. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００７５】
ここで、突出部５の斜面５ｂの傾斜角Ｂを小さくすれば、Ｆ２／Ｆ１が大きくなる。ところで、突出部５を回転させる力Ｆ１は、可動検出部２５に備えられる重り２３を適切に設定すれば、小さな力で回転可能にできる。
【００７６】
また、図１０（ｂ）は、原稿を原稿載置面２に対して平行で、かつ原稿搬送方向（図１０（ｂ）中の矢印Ｙ方向）に対して垂直な方向（図１０（ｂ）中の矢印Ｘ方向）から手で挿入した場合に、突出部５に発生する力を力学的に示している図である。なお、突出部５の設置角度をＡとする。
【００７７】
この場合、図１０（ｂ）に示すように、原稿から突出部５に加わる力Ｆｐは、分力ＦａとＦｂとなる。分力Ｆａは、突出部５を側面から押付ける力となる。また、分力Ｆｂによって、原稿が突出部５と接触しながら滑り、突出部５を原稿載置面２内部に押し込むことになる。この滑りが生じる条件は、下記の数式（２）の通りである。
【００７８】
【数２】

【００７９】
ここで、Ｆｂ／Ｆａ＝ｔａｎＡとなるので、突出部５の方向の角度Ａを大きくすれば、Ｆｂ／Ｆａが大きくなる。また、上記の角度Ａを１５度とした実験において、突出部５は機能した。すなわち、角度Ａが１５度であれば、原稿を原稿載置面２に対して平行で、かつ原稿搬送方向（図１０（ｂ）中の矢印Ｙ方向）に対して垂直な方向（図１０（ｂ）中の矢印Ｘ方向）から手で挿入した場合に、突出部５は原稿によって確実に原稿載置面２内部に押し下げられる。このため、原稿や突出部５が損傷することなく、原稿を確実に検知することができる。なお、角度Ａが１５度の場合、Ｆｂ／Ｆａは０．２７となる。（参考：テフロン（登録商標）どうし、またはテフロン（登録商標）と鋼鉄の摩擦係数は、０．０４である。）
また、分力Ｆｂについては、突出部５の傾斜面の角度を緩くすれば、小さな力で検出可能にできる。（参照：上記、図１０（ａ）の説明。）
また、図１０（ｃ）は、原稿を原稿載置面２に対して平行で、かつ原稿搬送方向（図１０（ｃ）中矢印Ｙ方向）に対して平行な方向（図１０（ｃ）中矢印Ｓ方向）から手で挿入した場合に、突出部５に発生する力を力学的に示している図である。ここでも、突出部５の設置角度をＡとする。
【００８０】
この場合、図１０（ｃ）に示すように、原稿から突出部５に加わる力Ｆｐは、分力ＦｃとＦｄとなる。分力Ｆｃは、突出部５を側面から押付ける力となる。また、分力Ｆｄによって、原稿が突出部５と接触しながら滑り、突出部５を原稿載置面２内部に押し込むことになる。この滑りが生じる条件は、下記数式（３）の通りである。
【００８１】
【数３】

【００８２】
ここで、Ｆｄ／Ｆｃ＝１／ｔａｎＡとなるので、突出部５の設置角度Ａを小さくすれば、Ｆｄ／Ｆｃが大きくなる。
【００８３】
以下に、突出部５の設置角度Ａがどの範囲であれば、原稿を原稿載置面２に対して平行で、かつ原稿搬送方向（図１０（ｂ）中の矢印Ｙ方向）に対して垂直な方向（図１０（ｂ）中の矢印Ｘ方向）から手で挿入した場合、および原稿を原稿載置面２に対して平行で、かつ原稿搬送方向（図１０（ｃ）中矢印Ｙ方向）に対して平行な方向（図１０（ｃ）中矢印Ｓ方向）から手で挿入した場合に、突出部５が適切に機能するか否かを調べた。その結果を下記の表１に示す。
【００８４】
【表１】

【００８５】
なお、このときの実験条件は、用紙サイズ：Ａ４、用紙枚数：２枚、６４ｇ／ｍ^２、突出部５の材質：ＡＢＳである。また、表中の○は良好、×は不良を表している。
【００８６】
上記表１の結果から、原稿搬送方向に対し、原稿検知センサ２０の可動検出部２５における突出部５の設置角度を、１５度〜７５度とすることが好ましいことがわかる。これは、設置角度Ａが小さすぎると、原稿搬送方向に垂直な方向（本体の手前側など）から、原稿を原稿検知センサ２０に当てたとき、原稿検知センサ２０の突出部５を押し下げる力が弱くなるためである。一方、設置角度Ａが大きすぎると、原稿搬送方向（原稿が本体の左右方向など）から、原稿を原稿検知センサ２０に当てたとき、原稿検知センサ２０における突出部５を押し下げる力が弱くなるためであると考えられる。
【００８７】
また、図２（ａ）（ｂ）に示すように、原稿検知センサ２０の可動検出部２５における突出部５を、原稿ガイド３における最小定型サイズ幅の範囲内に配置することが好ましい。すなわち、一対の原稿ガイド３が最小サイズ時の位置にある場合、その一対の原稿ガイド３の間に可動検出部２５を設けることが好ましい。これにより、確実に最小定型サイズ幅の原稿の有無や原稿サイズを検知可能になる。なお、上記最小定型サイズ幅以上の幅の原稿は、原稿ガイド３の設定可能な最大サイズ幅より小さければ、すべて検知可能になることはいうまでもない。
【００８８】
また、原稿検知センサ２０の突出部５を、原稿トレイ１１における原稿載置範囲（原稿載置面２）の中央部分から外して設置することが好ましい。例えば、画像形成装置１１０の正面にユーザーが立って、ユーザーから見て原稿搬送方向が左右方向になる場合、原稿検知センサ２０の突出部５を原稿の中央より奥側に配置すれば、原稿の中央または手前を手で持って、原稿トレイ１１に原稿を挿入し載置する場合でも、ユーザーの手と突出部５とがぶつかりにくくなる。したがって、ユーザーがケガすることを防止できる。
【００８９】
また、浮き上がり原稿への対策について図５を用いて、以下に説明する。図５は、浮き上がり原稿への対策について模式的に説明した図である。図５に示すように、原稿の折れ等により、原稿に浮き上がり部分が生じると、原稿が突出部５と接触せず、原稿検知センサ２０に検出されない場合がある。この対策として、原稿検知センサ２０の突出部５の検知部を高くする（図５中の点線部分）方法があるが、この場合、より一層、突出部５の側面５ｃと原稿とが接触する可能性が高くなる。すなわち、より一層、突出部５の側面５ｃと原稿とが衝突し、突出部５が適切に機能できず、突出部５または原稿が損傷する可能性が高くなる。しかし、かかる場合でも、本実施の形態にかかる構成を用いることによって、上記の問題を回避できる。すなわち、突出部５の側面５ｃと原稿との衝突によって、突出部５または原稿に損傷が発生することを防止できる。また、本発明を利用すれば、従来よりも突出部５を高く設けることもできる。突出部５を高く設定しても、突出部５または原稿に損傷が発生することを防止できるためである。
【００９０】
〔実施の形態２〕
本発明の用紙トレイに関する他の実施形態について、図８、図９、図１１に基づいて説明すれば、以下の通りである。なお、説明の便宜上、前記実施の形態１にて説明した部材と同じ機能を有する部材については、同じ符号を付記し、その説明を省略する。
【００９１】
図９（ａ）は、用紙トレイに設けられる原稿検知センサの他の実施形態を模式的に示す図であり、図９（ｂ）は、（ａ）の断面図である。また、図９（ｃ）（ｄ）は、図９（ａ）の原稿検知センサに原稿があたった場合の様子を模式的に示した図である。
【００９２】
図９（ａ）に示すように、本実施の形態に示す原稿検知センサ２０は、原稿トレイ１１上に、原稿載置面２に対して水平方向に回転可能に設置されている。具体的には、原稿検知センサ２０は、回転する回転円板２６と、回転円板２６に対して略垂直に、回転円板２６から突出している突出部５とを備えている。突出部５は、回転円板２６の回転中心から離れて設けられている。
【００９３】
なお、本実施の形態では突出部５は、その長手方向が回転円板２６の直径方向と平行になるように設けられているが、特にこれに限られるものではなく、例えば、回転円板２６の直径方向に対し傾けて設けられていてもよい。
【００９４】
また、図９（ｃ）に示すように、原稿載置面２内方向からの原稿の挿入し載置により、原稿が突出部５に当たり、突出部５が押され、原稿検知センサ２０が原稿載置面２上で回転する。そして、原稿挿入方向に突出部５の方向が近づき、効率よく押し下げられる。
【００９５】
すなわち、例えば、図９（ｃ）に示すように、挿入された原稿が、突出部５の側面５ｃに衝突する場合、通常、突出部５は適切に機能せず、突出部５は原稿によって原稿載置面２内部に押し込まれることはない。しかし、本実施の形態にかかる原稿検知センサ２０によれば、挿入された原稿が、突出部５の側面５ｃに衝突する場合、突出部５は原稿に押されて、回転円板２６が原稿載置面２上で水平に回転することになる（図９（ｄ）参照）。そして、回転円板２６が回転し、原稿が突出部５の斜面（５ａまたは５ｂ）と接触すると、原稿によって突出部５は原稿載置面２内部（回転円板２６内部）に押し込まれる。したがって、原稿が原稿検知センサ２０の突出部５の側面５ｃと衝突する場合でも、原稿または突出部５に損傷が発生することを防止することができるとともに、確実に原稿を検知することができる。
【００９６】
なお、回転円板２６の回転をなめらかにするため、回転円板２６の下側の回転軸（回転中心）付近に、軸受け（不図示）を設けてもよい。
【００９７】
また、突出部５を原稿載置面２上で所定方向（所定の位置）に復帰するように設定することが好ましい。すなわち、原稿検知センサ２０における突出部５は、原稿と接触していないとき、所定の方向を向くように設定されていることが好ましい。
【００９８】
具体的には、例えば、原稿載置面２が傾斜している場合、原稿検知センサ２０における回転円板２６に重りを付け、重りをつけた方が下側に向くことを利用し、所定方向に向かせる方法を用いることができるが、この方法に限定されるわけではない。また、重りのほかに、突出部５の位置を所定の位置に戻すための手段としては、例えば、バネ等の弾性体、またはモータ等を利用することが可能である。
【００９９】
これにより、ユーザーがケガすることを回避することができる。すなわち、例えば、原稿の載置により、突出部５がユーザーから見て手前側に来ており、突出部５がそのままの状態で、再び原稿が載置される場合は、ユーザーの手が突出部５とぶつかりやすくなるという問題があるが、上記の構成によれば、この問題を回避することができる。
【０１００】
また、図８（ａ）に、用紙トレイに設けられる原稿検知センサの他の実施形態を模式的に示す。図８（ｂ）は、図８（ａ）の断面図である。この図８（ａ）（ｂ）に示すように、原稿載置面２上に、原稿載置面２に対して水平方向に回転可能に設けられている回転円板２６に、突出部５を設置することにより、原稿検知センサ２０の突出部５の方向を手で設定できるようになる。これにより、原稿検知センサ２０の突出部５の設置方向をユーザーが適宜、手動設定できる。
【０１０１】
また、例えば、バネ等の弾性部材（不図示）を用い、原稿検知センサ２０の突出部５を、上下に動くようすることもできる。
【０１０２】
また、図１１は、用紙検知センサ３５を設けた手差し給紙トレイ３０を示す図である。図１１に示すように、手差し給紙トレイ３０は、用紙載置面３２、給紙ガイド３３、用紙検知センサ３５を備えている。なお、用紙載置面３２は上述の原稿載置面２と、給紙ガイド３３は上述の原稿ガイド３と、用紙検知センサ３５は上述の原稿検知センサ２０と同様の構成である。すなわち、ここまで原稿検知センサ２０を設けた原稿トレイ１１について説明してきた動作、作用、効果は、用紙検知センサ３５を設けた手差し給紙トレイ３０についても適用できる。すなわち、用紙を手差し給紙トレイ３０に、給紙搬送方向に垂直な方向から挿入し載置する場合、あるいは、給紙搬送方向から挿入し載置する場合でも、用紙検知センサ３５の破損、あるいは、用紙の損傷を防止することができる。また、用紙検知センサ３５が確実に機能するため、確実に用紙を検知することができる。さらに、用紙検知センサ３５を、用紙載置面３２に対して水平に回転可能に設ける場合も、上記原稿トレイ１１の場合と同様に、例えば、用紙を手に持って手差し給紙トレイ３０に対して挿入する場合、用紙検知センサ３５は回転することになるため、どのような方向から用紙の挿入（載置）が行われる場合でも、用紙検知センサ３５の破損や、用紙の損傷を防止することができる。
【０１０３】
本発明は上述した各実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。
【０１０４】
【発明の効果】
本発明の用紙トレイは、以上のように、原稿または用紙を載置するための用紙載置面と、原稿または用紙を検知するために、上記用紙載置面に設けられている検知部とを備えており、上記検知部は、上記用紙載置面に対して略垂直に突出している突出部を有する可動検出部を備えている接触式の検知センサであり、上記可動検出部における突出部は、その設置方向が、原稿または用紙搬送方向に対して、略平行とならず、かつ略垂直とならないように、上記用紙載置面に設けられているという構成である。
【０１０５】
それゆえ、本発明にかかる用紙トレイに原稿等を、例えば、原稿等の搬送方向に垂直な方向から挿入し載置する場合、あるいは、原稿等の搬送方向から挿入し載置する場合でも、検知部における突出部の破損、あるいは、原稿等の損傷を防止することができるという効果を奏する。また、上記突出部が確実に機能するため、確実に原稿等を検知することができるという効果も奏する。
【０１０６】
また、本発明の用紙トレイは、以上のように、原稿または用紙を載置するための用紙載置面と、原稿または用紙を検知するために、上記用紙載置面に設けられている検知部とを備えており、上記検知部は、上記用紙載置面に対して略垂直に突出している突出部を有する可動検出部を備えている接触式の検知センサであるとともに、上記可動検出部における突出部は、上記用紙載置面に、用紙載置面に対して水平方向に回転可能に設けられているという構成である。
【０１０７】
それゆえ、例えば、原稿等を手に持って用紙トレイに対して挿入する場合、検知部は回転することになるため、どのような方向から原稿等の挿入（載置）が行われる場合でも、検知部における突出部の破損や、原稿等の損傷を防止することができるという効果を奏する。また、上記突出部が確実に機能するため、確実に原稿等を検知することができるという効果を奏する。
【０１０８】
また、本発明の用紙トレイは、自動原稿送り装置、および画像形成装置に利用することも可能である。それゆえ、検知部における突出部または原稿等が損傷することがないとともに、確実に原稿等を検知できる自動原稿送り装置、および画像形成装置を得ることができるという効果を奏する。
【図面の簡単な説明】
【図１】本実施の一形態に係る原稿トレイの構造を模式的に示す斜視図である。
【図２】（ａ）は、本実施の一形態に係る原稿トレイの構造を上から見た図であり、（ｂ）は、（ａ）を矢印Ｚ方向から見た図である。
【図３】本実施の一形態に係る自動原稿送り装置の構造を模式的に示す断面図である。
【図４】（ａ）（ｂ）は、本実施の一形態にかかる原稿検知センサの構成例とその動作を模式的に示す図である。
【図５】浮き上がり原稿への対策について模式的に説明した図である。
【図６】本実施の一形態に係る画像形成装置の構造を模式的に示す図である。
【図７】（ａ）（ｂ）は、本実施の一形態にかかる可動検出部における突出部の形状の他の一例を模式的に表す図である。
【図８】（ａ）は、用紙トレイに設けられる原稿検知センサの他の実施形態を模式的に示すずであり、（ｂ）は、（ａ）の断面図である。
【図９】（ａ）は、用紙トレイに設けられる原稿検知センサの他の実施形態を模式的に示す図であり、（ｂ）は、（ａ）の断面図であり、（ｃ）（ｄ）は、（ａ）の原稿検知センサに原稿があたった場合の様子を模式的に示した図である。
【図１０】（ａ）は、原稿を原稿載置面に平行な方向から手で挿入した場合に、突出部に発生する力を力学的に示している図であり、（ｂ）は、原稿を原稿載置面に対して平行で、かつ原稿搬送方向に対して垂直な方向から手で挿入した場合に、突出部に発生する力を力学的に示している図であり、（ｃ）は、原稿を原稿載置面に対して平行で、かつ原稿搬送方向に対して平行な方向から手で挿入した場合に、突出部に発生する力を力学的に示している図である。
【図１１】本実施の一形態にかかる用紙検知センサを設けた手差し給紙トレイを示す図である。
【図１２】（ａ）は従来のデジタル複写機に設けられる原稿トレイを上から見た図であり、（ｂ）は（ａ）の斜視図である。
【符号の説明】
２ 原稿載置面（用紙載置面）
５ 突出部
５ａ 突出部の斜面
５ｂ 突出部の斜面
５ｃ 突出部の側面
１０ 自動原稿送り装置
１１ 原稿トレイ（用紙トレイ）
２０ 原稿検知センサ（検知部）
２５ 可動検出部
３０ 給紙トレイ（用紙トレイ）
３２ 用紙載置面
３５ 用紙検知センサ（検知部）
１１０ 画像形成装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a paper tray used for an automatic document feeder or a paper feeder, and to an automatic document feeder and an image forming apparatus using the same.
[0002]
[Prior art]
2. Description of the Related Art Generally, an image forming apparatus such as a copying machine and a document reading apparatus such as a scanner have an automatic document feeder that automatically conveys a document to a document reading unit. This automatic document feeder includes a document (paper) tray on which a document is placed, and the document tray has a document detection sensor for detecting a document size or the presence or absence of a document. That is, when copying a document or reading a document, the document detection sensor detects the size of the document or the presence or absence of the document, and conveys the document on the document tray to the image reading unit of the apparatus body. Next, an image of the document is read by an image reading unit of the apparatus main body, and an image is formed in the case of a copying machine.
[0003]
Here, as an example of the document detection sensor, there is a contact type document detection sensor. FIG. 12A is a top view of a document tray provided in a conventional digital copying machine, and FIG. 12B is a perspective view of FIG. As shown in FIGS. 12A and 12B, the document tray 50 includes two contact-type document detection sensors 51. The contact type document detection sensor 51 is provided on the document tray 50 so as to protrude from the document placement surface 52 of the document tray 50. The protruding portion of the document detection sensor 51 has a substantially triangular shape (thin triangular prism having a small thickness), and is formed substantially perpendicular to the document placing surface 52. The projecting portion of the contact-type document detection sensor 51 is installed so that two substantially triangular slopes are parallel to the document transport direction.
[0004]
The protruding portion of the document detection sensor 51 is provided so as to be rotatable around a rotation axis (not shown), and is pushed into or protruded into the document placement surface 52 by this rotation. That is, when the original is inserted and placed on the original placing surface 52 and the inclined surface of the projecting portion of the original detecting sensor 51 comes into contact with the original, the original detecting sensor 51 is pushed into the original placing surface 52 by the original, Detect the original.
[0005]
As an example of such a contact type document detection sensor, there is disclosed one in which a rear end detection sensor provided on a document tray substantially in parallel with the document conveyance direction detects the rear end of the document and recognizes the document size. (For example, see Patent Document 1). Japanese Patent Application Laid-Open No. H11-163873 discloses that by providing an irregular surface on a document tray, the central portion in the longitudinal direction of the document is curved symmetrically with respect to the line, so that the rear end position of the document can be reliably detected even when there are several documents. It is shown.
[0006]
Further, in an image forming apparatus such as a copying machine or a printer, a manual paper feed tray (manual paper feed unit) is provided to enable external paper feeding operation. A paper detection sensor is also provided on such a manual paper feed tray. This paper detection sensor is also a contact-type detection sensor generally having a protrusion having the same configuration as the above-described document detection sensor, and two substantially triangular slopes at the protrusion are provided on the manual paper feed tray in the paper transport direction. It is installed so as to be parallel to. The paper detection sensor detects the paper size or the presence or absence of the paper, and feeds the paper when executing copy or print.
[0007]
[Patent Document 1]
JP-A-8-290835 (publication date: November 5, 1996)
[0008]
[Problems to be solved by the invention]
Here, when an original is inserted into the original tray and placed on the image forming apparatus or the image reading apparatus, or when paper is inserted and placed on the manual feed tray, the user is required to transport the original or paper of the apparatus. A document or the like is inserted and placed from the direction (arrow Y direction in FIG. 12A), or a document is inserted from a direction perpendicular to the transport direction of the document or the like (arrow X direction in FIG. 12A). , Is generally placed.
[0009]
However, in the document tray or the manual paper feed tray having the conventional contact-type document (paper) detection sensor as described above, the contact-type document (paper) detection sensor has two substantially triangular slopes at the protruding portion. It is installed so as to be parallel to the transport direction. For this reason, for example, the original is inserted into the contact-type original detection sensor 51 from a direction (arrow X direction in FIG. 12A) perpendicular to the original conveyance direction (arrow Y direction in FIG. 12A). Then, the original collides with the side surface (the side surface other than the substantially triangular slope) of the protruding portion of the original detection sensor 51. For this reason, the document detection sensor 51 does not function at all and cannot sink into the document placing surface 52. As a result, there is a problem that the contact-type original detection sensor 51 is damaged or the original (paper) is damaged.
[0010]
Also, when the original is hit against the original detection sensor 51 from a direction in which the original detection sensor is unlikely to sink (a direction perpendicular to the rotation axis and far from the rotation axis), the sensor becomes difficult to move, and It is hard to be pushed into. Also in such a case, the document and the document detection sensor 51 may collide, and the document detection sensor 51 may be damaged. Conversely, the document may be damaged.
[0011]
Further, when the document detection sensor 51 is not properly pushed into the document placing surface 52, there is a problem that the document cannot be reliably detected. As a result, for example, the image reading process and the image forming process cannot be performed properly.
[0012]
Further, for example, when the document on the document tray 50 rises due to distortion or the like, the document does not contact the document detection sensor 51, and the document detection sensor 51 cannot detect the document. As a countermeasure against such a situation, it is general to increase the height of the document detection sensor 51. However, when the height of the document detection sensor 51 is increased, the document detection sensor 51 is not pushed into the document placement surface 50 when a document is inserted or stacked, and the possibility that the document and the document detection sensor 51 collide with each other increases. It is easy to cause the above problem.
[0013]
Further, Patent Document 1 does not mention at all such a problem, that is, an adverse effect when a document collides with a trailing edge detection sensor.
[0014]
Although the description is omitted here, the same problem also occurs in the paper detection sensor in the manual paper feed tray.
[0015]
The present invention has been made in view of the above problems, and an object of the present invention is to prevent damage to a detection sensor caused by a collision between a document or paper and a detection sensor, or damage to a document and the like, and reliably An object of the present invention is to provide a paper tray capable of detecting a document or the like, an automatic document feeder using the same, and an image forming apparatus.
[0016]
[Means for Solving the Problems]
In order to solve the above-described problems, the paper tray of the present invention is an automatic document feeder that conveys a document to a document reading unit, or a paper tray that is provided in a paper feeding device that feeds a sheet to an image forming unit. The paper tray includes a paper mounting surface for mounting a document or paper, and a detecting unit provided on the paper mounting surface for detecting the document or the paper. A contact detection sensor having a movable detection unit having a protrusion protruding substantially perpendicularly to the sheet mounting surface, and the protrusion in the movable detection unit has an installation direction of a document or It is characterized in that it is provided on the sheet mounting surface so as not to be substantially parallel to and not substantially perpendicular to the sheet transport direction.
[0017]
According to the above configuration, for example, when a document or paper (hereinafter, referred to as a document or the like) is inserted and placed on a paper tray in a direction perpendicular to the direction in which the document or the like is transported, or in a direction in which the document or the like is transported. Even when inserting and placing, the protruding portion can always appropriately contact the original or the like, and is pushed into the sheet placing surface. For this reason, it is possible to prevent the protrusion or the document from being damaged due to the protrusion not being pushed into the sheet placing surface and colliding between the protrusion and the document.
[0018]
In addition, since the protruding portion functions reliably (is pushed into the sheet placing surface), the original or the like can be reliably detected. When the height of the sensor is increased as a countermeasure against erroneous detection due to a folded document or the like, damage to the detection unit (sensor) increases, but the present invention is also effective as a countermeasure.
[0019]
Note that the “installation direction” of the protrusion in the present invention refers to the longitudinal direction of the protrusion, and “the installation direction is not substantially parallel to the document or paper transport direction, and is substantially perpendicular. The term “provided so as not to be provided” means that the protruding portion is provided so that the longitudinal direction thereof is not substantially parallel to the document or sheet transport direction and is not substantially perpendicular to the document or sheet transport direction.
[0020]
In addition, the detection unit that functions as the “contact-type detection sensor” in the present invention includes, for example, a shape in which the protrusion of the movable detection unit has a slope and a surface other than the slope (for example, a shape in which the protrusion has a substantially triangular shape). In the case of, the protruding portion has a slope and a side surface), and when the slope and the document or the like come into contact with each other, the protruding portion is pushed into the inside of the sheet placing surface and the presence of the document or the like can be detected. In the case where a document other than the above-mentioned inclined surface comes into contact with a document or the like, the protruding portion is not pushed into the inside of the sheet placing surface and the presence of the document or the like cannot be detected. is not.
[0021]
The phrase “the protrusion properly contacts the document or the like” means that the protrusion is pushed into the sheet placement surface when the slope of the protrusion contacts the document or the like.
[0022]
Preferably, the paper tray includes at least one or more detection units.
[0023]
In order to solve the above-described problems, the paper tray of the present invention is an automatic document feeder that conveys a document to a document reading unit, or a paper tray that is provided in a paper feeding device that feeds a sheet to an image forming unit. The paper tray includes a paper mounting surface for mounting a document or paper, and a detecting unit provided on the paper mounting surface for detecting the document or the paper. A contact-type detection sensor having a movable detection unit having a protrusion protruding substantially perpendicular to the sheet placement surface, and the protrusion in the movable detection unit is provided on the sheet placement surface. Are provided so as to be rotatable in the horizontal direction with respect to the sheet mounting surface.
[0024]
According to the above configuration, for example, when a document or the like is inserted into the paper tray while being held in a hand, the document or the like hits the protruding portion and pushes the protruding portion. As a result, the detection unit rotates to a position where the protrusion appropriately contacts the original or the like. That is, the protruding portion is oriented in the direction of insertion of the original or the like, and the rotation fulcrum is oriented in front of the insertion of the original. Thus, regardless of the direction in which a document or the like is inserted (placed) from any direction, the direction of the protruding portion changes in accordance with the direction of insertion (placement) of the document, and the protruding portion always always appropriately fits the document or the like. Can contact with Therefore, it is possible to prevent the protrusion and the document from being damaged due to the protrusion not being pushed in and colliding between the protrusion and the document.
[0025]
In addition, since the protruding portion functions reliably (is pushed into the sheet placing surface), the original or the like can be reliably detected. When the height of the sensor is increased as a countermeasure against erroneous detection due to a folded document or the like, damage to the detection unit (sensor) increases, but the present invention is also effective as a countermeasure. Although the case where the original is placed on the paper tray has been described here, the same effect can be obtained when paper is fed to the paper tray used for the paper feeding device.
[0026]
Further, when a document or the like comes into contact with the detection unit from the inside of the document or sheet placement surface, it is preferable that the rotation fulcrum side of the movable detection unit be directed toward the document or the sheet insertion side.
[0027]
In the paper tray according to the present invention, in order to solve the above-described problem, the mounting direction of the protrusion in the movable detection unit is in a range of 15 to 75 degrees with respect to the document or paper conveyance direction. It is characterized by being provided as follows.
[0028]
If the mounting angle of the protrusion in the movable detection unit is too small, when the document or the like is inserted into the paper tray from the direction perpendicular to the conveyance direction of the document or the like and placed, the document and the protrusion may not properly contact with each other. Therefore, the force for pushing the protruding portion into the sheet placement surface is weakened. Similarly, even when the installation angle is too large, when the originals and the like are inserted into the paper tray and placed in the paper tray from the transport direction of the originals and the like, the originals and the protruding portions cannot be appropriately contacted with each other, and the force for pushing down the protruding portions is not sufficient. Becomes weaker.
[0029]
However, by setting the installation angle of the protruding portion as in the above configuration, the document and the like can appropriately contact the protruding portion, and the protruding portion can be reliably pushed down into the sheet placement surface. Therefore, it is possible to accurately detect the original or the like without damaging the original or the like or the protrusion.
[0030]
The “installation angle” of the protruding portion refers to an angle formed by the installation direction (longitudinal direction) of the protruding portion and the conveyance direction of a document or the like.
[0031]
In order to solve the above problem, the paper tray of the present invention is characterized in that the shape of the protruding portion in the movable detection section is substantially triangular.
[0032]
According to the configuration described above, the protrusion in the movable detection unit is substantially triangular (for example, a triangular prism having a small thickness), so that the protrusion has a slope and a side surface. For this reason, for example, even when a document or the like is inserted and placed on the paper tray from a direction perpendicular to the direction in which the document is transported, or when the document or the like is inserted and placed in the paper tray from the direction in which the document is transported, the document or the like protrudes. The original or the like pushes the slope on one slope of the triangle of the section, and the protruding portion is securely pushed into the inside of the sheet placement surface. Therefore, it is possible to accurately detect the original or the like without damaging the original or the like or the protrusion.
[0033]
Also, for example, when the detection unit is provided rotatably, even if the inserted and placed document or the like contacts the side surface of the protrusion, the protrusion is rotated by being pushed by the document or the like, The slope of the protruding portion comes into contact with the document or the like. This ensures that the protruding portion is pushed into the sheet placement surface. Therefore, it is possible to accurately detect the original or the like without damaging the original or the like or the protrusion.
[0034]
In order to solve the above-mentioned problems, the paper tray of the present invention is characterized in that the slope of the slope of the substantially triangular protrusion is formed gently.
[0035]
According to the above configuration, even when the original or the like comes into contact with any inclined surface of the protrusion from the horizontal direction, the protrusion is reliably pushed into the sheet placement surface. Therefore, it is possible to accurately detect the original or the like without damaging the original or the like or the protrusion. Further, since the slope of the slope of the protrusion is gentle, the impact when the document or the like comes into contact with the protrusion is reduced. For this reason, it is possible to further prevent damage to a document or the like or damage to a protruding portion.
[0036]
Note that "the slope of the slope at the protrusion is gentle" means, for example, that the protrusion is gentle enough that the protrusion is easily pushed into the sheet placement surface when a document or the like comes into contact with the slope of the protrusion. Well, it is not particularly limited. For example, it is preferable that the inclination angle of the slope of the protrusion is in a range of 60 degrees or less.
[0037]
The same effect can also be obtained by reducing the slope of the projection of the contact-type movable detection section on the side opposite to the rotation fulcrum.
[0038]
In order to solve the above-mentioned problem, in the paper tray of the present invention, at least one of the protruding portions of the movable detection section is provided within a range of a minimum width of the standard size paper on the paper mounting surface. It is characterized by having.
[0039]
According to the above configuration, it is possible to always reliably detect the size of an original or the presence of an original or the like for an original or the like having a width equal to or greater than the minimum width of a standard size sheet.
[0040]
In order to solve the above-mentioned problem, the paper tray according to the present invention is characterized in that the protruding portion of the movable detection section is provided off the center of the paper mounting surface.
[0041]
Usually, when a manuscript or the like is held in a hand, the manuscript or the like is often held in the center or near side. For this reason, when a document or the like is held by hand and inserted into the paper tray and placed, the hand may collide with the protruding portion and may be injured.
[0042]
However, according to the above configuration, even when the document or the like is placed on the paper tray while holding the center or the front of the document or the like, it is difficult for the hand to hit the protruding portion. Therefore, it is possible to prevent injuries when placing a document or the like.
[0043]
The “central portion of the sheet placing surface” refers to, for example, a portion of the sheet placing surface corresponding to the central portion of the document or the like when a document or the like is inserted and placed in the sheet tray.
[0044]
In the paper tray of the present invention, in order to solve the above problem, the installation direction of the protrusion in the movable detection unit is set so as to face a predetermined direction when not in contact with a document or paper. It is characterized by.
[0045]
For example, if the protruding portion of the movable detection unit is stopped at a position (front side) where a document or the like is inserted, the protruding portion and the hand are likely to collide with each other when the document or the like is placed on the paper tray. Therefore, as in the above configuration, when a document or the like is placed on the paper tray, if the projection is set to return to a predetermined position where the hand does not easily collide with the hand, the hand may collide with the projection. This can prevent the occurrence of injury.
[0046]
Note that the “predetermined position” may be any position where it is difficult for the protruding portion to hit the hand when a document or the like is placed on the paper tray. When the paper tray is placed, a position far from the user side of the paper tray (for example, a side opposite to the side where the user inserts and places the paper tray (back side)) may be used.
[0047]
According to another aspect of the invention, there is provided an automatic document feeder including any one of the above-described paper trays.
[0048]
According to the above configuration, it is possible to obtain an automatic document feeder capable of reliably detecting a document or the like while preventing a protrusion or a document or the like in the detection unit from being damaged.
[0049]
According to another aspect of the invention, there is provided an image forming apparatus including any one of the above-described paper trays.
[0050]
According to the above configuration, it is possible to obtain an image forming apparatus that does not damage the protruding portion or the document or the like of the detection unit and can reliably detect the document or the like.
[0051]
BEST MODE FOR CARRYING OUT THE INVENTION
[Embodiment 1]
One embodiment of a paper tray, an automatic document feeder, and an image forming apparatus according to the present invention will be described below with reference to FIGS. 1 to 7 and FIG.
[0052]
First, an outline of the image forming apparatus according to the present embodiment will be described, and then, a paper tray (document tray) which is a characteristic part of the present invention will be described sequentially.
[0053]
(1) Image forming apparatus
FIG. 6 is a diagram schematically illustrating the structure of the image forming apparatus 110 according to the present embodiment. As shown in FIG. 6, the image forming apparatus 110 has a document table 670 made of transparent glass or the like on the upper surface. An optical system for reading a document is provided below the document table 670. This optical system includes an exposure light source 671 for irradiating light to a document placed on a document table 670, and a plurality of reflecting mirrors 672 for guiding light to an imaging lens and a photoelectric conversion element (hereinafter referred to as a CCD) 673. Be composed.
[0054]
An automatic document feeder 10 that automatically conveys a document and performs a reading operation of the document is installed above the document table 670. When the originals are set on the original tray 11, the automatic original feeder 10 feeds the originals one by one and feeds the originals into the paper feed path 682. The fed document is temporarily stopped with its leading end pressed against the PS roller 683. This synchronizes with the printing unit (image forming unit) 600 and prevents the original from being sent to the reading unit in a skewed state. When the clutch (not shown) is turned on, the PS roller 683 is connected to the drive unit of the transport motor (not shown), and the transportation of the temporarily stopped document is resumed. The details of the automatic document feeder 10, which is a characteristic part of the present invention, will be described later.
[0055]
The above-described exposure light source 671 is moved to a position immediately below the document reading unit 688, and the document is irradiated with light in synchronization with the start of document transport. The light is guided to the CCD 673 through each part of the optical system described above.
[0056]
The document image data read by the CCD 673 is subjected to image processing, and a laser scanning unit (hereinafter referred to as LSU) irradiates a laser beam onto the surface of an image carrier (hereinafter referred to as a photoconductor) 602 to form an electrostatic latent image. Is formed.
[0057]
The photoconductor 602 is formed in a drum shape and is driven to rotate. A developing device 611 that develops an electrostatic latent image on the surface of the photoconductor 602 exposed by the laser from the laser irradiation point toward the rotation direction of the photoconductor 602 from the laser irradiation point to a visible image with toner is arranged around the photoconductor 602. You. A transfer charger 613 for transferring the toner image on the photoconductor 602 to paper; a cleaning device for removing residual toner on the surface of the photoconductor 602; a charging unit for charging the surface of the photoconductor 602 to a predetermined potential; LSUs for irradiating the laser toward are arranged in order.
[0058]
The paper is stored in the paper cassette 630. At the leading end of the paper cassette 630, a half-moon roller 631 for feeding the paper into the paper feed path 633 is disposed downstream (for convenience, the paper flow <cassette side> is upstream, and the paper discharge side> (Not shown) A pre-registration detection switch (not shown) for detecting the passage of the paper, a PS roller 632 for aligning the toner image on the photoconductor 602 with the paper based on a signal of the pre-registration detection switch, a paper A fixing roller 605 for fixing the toner image on the paper by a heating roller and a pressure roller, a fixing paper detection switch (not shown) for detecting that the paper has passed through the fixing roller 605, and a paper on the paper discharge conveyance path 635. A paper discharge detection switch (not shown) for detecting the passage and a paper discharge roller 636 for discharging the paper are arranged.
[0059]
The sheet passes through the above-described members from the sheet cassette 630 and is discharged to the sheet discharge tray 660, thereby completing a series of image forming steps.
[0060]
Further, the image forming apparatus 110 includes a manual paper feed tray 30 so as to enable manual paper feed.
[0061]
(2) Document tray (paper tray)
FIG. 1 is a perspective view schematically showing the structure of a document tray 11 according to the embodiment. FIG. 2A is a diagram of the structure of the document tray 11 according to the present embodiment as viewed from above, and FIG. 2B is a diagram of FIG. 2A as viewed from the direction of arrow Z. . FIG. 3 is a sectional view schematically showing the structure of the automatic document feeder 10 according to the embodiment.
[0062]
As shown in FIG. 3, the automatic document feeder 10 includes a document tray 11 at an upper portion thereof. As shown in FIGS. 1, 2A, 2B, and 3, the document tray 11 includes a document detection sensor 20, a document guide 3, and a document mounting surface 2. The document detection sensor 20 includes a movable detection unit 25, which will be described later. The movable detection unit 25 has a protrusion 5 that protrudes from the document placement surface 2 of the document tray 11. In this embodiment, two document detection sensors 20 are provided, but the number of document detection sensors 20 is not particularly limited as long as it is a number suitable for detecting a document.
[0063]
The document placing surface 2 is a surface on which a document is placed. The document guide 3 includes a pair of guide plates, guides the side of the document to be conveyed, and is used according to the width of the document. When one of the two guide plates of the document guide 3 moves, the other guide plate also moves symmetrically. Thus, the center of the original and the center of the original placing surface 2 always coincide with each other regardless of the difference in the original size, that is, the difference in the width of the original when the original is placed. Therefore, the document can be reliably and accurately conveyed to the document reading unit. Also, by moving the document guide 3 according to the document size and determining the set position of the document guide 3, the document width can be detected.
[0064]
FIGS. 2A and 2B show the position of the document guide 3 at the minimum size and the position at the maximum size. The “position of the document guide 3 at the minimum size” refers to the position of the smallest paper width that can be set by the document guide 3. Similarly, “the position of the document guide 3 at the maximum size” refers to the position of the largest sheet width that can be set by the document guide 3.
[0065]
(3) Document detection sensor
Hereinafter, the document detection sensor 20 will be described. FIGS. 4A and 4B are diagrams schematically illustrating a configuration example of the document detection sensor 20 and its operation. As shown in FIGS. 4A and 4B, the document detection sensor 20 is a so-called contact type detection sensor that includes a movable detection unit 25, a photo sensor 21, a light shielding rib 22, a weight 23, and a rotation fulcrum 24. is there. The movable detection section 25 has a protruding section 5 protruding from the document placing surface 2. The projecting portion 5 is provided so as to project substantially perpendicularly to the document placing surface 2. Further, the movable detection unit 25 is rotatably held around a rotation fulcrum 24, and has a weight 23 at an end opposite to the protrusion 5. As the movable detection unit 25 rotates about the rotation fulcrum 24, the protrusion 5 is pushed into the document placing surface 2 or projects from the document placing surface 2.
[0066]
As shown in FIGS. 4A and 4B, the shape of the protrusion 5 is substantially triangular (thin triangular prism shape), and the protrusion 5 has two slopes 5a and 5b and a side surface 5c. have. The slope 5a is a slope opposite to the rotation fulcrum 24, and the slope 5b is a slope opposite to the rotation fulcrum 24. For example, when a document hits the slope 5b of the protruding portion 5, the protruding portion 5 is pushed into the inside of the document placing surface 2, and the presence of the document is detected. Hereinafter, the relationship between the operation of the protruding portion 5 and document detection will be briefly described.
[0067]
As shown in FIG. 4A, when there is no original, the protruding portion 5 is provided so as to protrude from the original placing surface 2. In this case, the light-blocking rib 22 blocks the photo sensor 21 and detects that there is no original. On the other hand, when the original is inserted and placed on the original placing surface 2, the projecting portion 5 is pushed into the original placing surface 2 by the original. In this case, the light-blocking rib 22 does not block the photosensor 21 and detects the presence of a document.
[0068]
FIGS. 7A and 7B are diagrams schematically illustrating another example of the shape of the protruding portion 5 in the movable detection unit 25. FIG. As shown in FIG. 7, it is also possible to form both the slopes 5a and 5b present on the projecting portion 5 having a substantially triangular shape gently. By gently forming the slope 5a on the opposite side to the rotation fulcrum 24 in this manner, for example, as shown in FIGS. When the original is inserted and placed, the original comes into contact with the slope 5 a of the protruding portion 5, and the protruding portion 5 is reliably pushed into the original mounting surface 2. Therefore, even when a document is inserted and placed on the document tray 11 from the side opposite to the rotation fulcrum 24, the document can be reliably detected. When the original comes into contact with the side surface 5 c of the protruding portion 5, the protruding portion 5 is not pushed into the document placing surface 2. Further, even when the original comes into contact with the vertex portion of the protruding portion 5 which is in contact with the slopes 5a and 5b, the protruding portion 5 is of course pushed into the document mounting surface 2.
[0069]
The shape of the protruding portion 5 is not limited to the above-described substantially triangular shape, but may be any shape as long as the protruding portion 5 is pressed into the document placing surface 2 by contacting the document or paper. You may. Further, the protruding portion 5 does not need to be a polyhedron formed of a straight line, but may be a shape formed by a gentle curve, for example, a substantially triangular shape formed by a gentle curve. .
[0070]
Further, as shown in FIGS. 1 and 2A and 2B, the protruding portion 5 is not substantially parallel to the document transport direction (the direction of the arrow Y in FIG. It is provided so as not to be vertical. That is, as shown in FIGS. 2A and 7A, the regions (points) where the slopes 5a and 5b of the protruding portion 5 and the document placing surface 2 substantially contact each other are denoted by 5a 'and 5b'. The direction (ie, the longitudinal direction of the protruding portion 5) connecting the regions (points) 5a 'and 5b' is provided so as not to be substantially parallel to and substantially perpendicular to the document transport direction. Have been. Note that the installation angle A of the protrusion 5 in the present embodiment is 20 degrees (see FIG. 2A).
[0071]
Thus, for example, when a document is inserted and placed in a direction perpendicular to the document transport direction (the direction of arrow X in FIG. 2A), or when the document is transported (in the direction of arrow Y in FIG. 2A). ), The original does not collide with the side surface 5c of the protruding portion 5 and comes into contact with the inclined surface 5b (or the inclined surface 5a or 5b in the configuration of FIG. 7). The protrusion 5 is reliably pushed into the document placing surface 2 by the document. Thus, the document and the document detection sensor 20 can be prevented from being damaged, and the document can be reliably detected.
[0072]
Hereinafter, the setting of the installation angle A of the protrusion 5 will be described. FIG. 10A shows dynamically the force generated in the protruding portion 5 when a document is manually inserted from a direction parallel to the document placing surface 2 (the direction of arrow Q in FIG. 10A). FIG.
[0073]
As shown in FIG. 10A, the force F applied to the protruding portion 5 from the document becomes the component forces F1 and F2. The component force F1 is a force for rotating the protrusion 5. In addition, the original component slides while contacting the protruding portion 5 due to the component force F <b> 2, and pushes the protruding portion 5 into the inside of the original mounting surface 2. The condition under which this slip occurs is as shown in the following equation (1).
[0074]
(Equation 1)

[0075]
Here, if the inclination angle B of the slope 5b of the protrusion 5 is reduced, F2 / F1 increases. By the way, the force F1 for rotating the protruding portion 5 can be made rotatable with a small force by appropriately setting the weight 23 provided in the movable detection portion 25.
[0076]
FIG. 10B shows a direction in which the original is parallel to the original placing surface 2 and perpendicular to the original transport direction (the direction of the arrow Y in FIG. 10B) (FIG. 10B). It is a figure which shows dynamically the force which generate | occur | produces in the protrusion part 5 when it inserts by hand from the arrow X direction inside). Note that the installation angle of the protruding portion 5 is A.
[0077]
In this case, as shown in FIG. 10B, the force Fp applied to the protruding portion 5 from the document becomes the component forces Fa and Fb. The component force Fa is a force for pressing the protrusion 5 from the side. In addition, the document slides while contacting the protruding portion 5 due to the component force Fb, and the protruding portion 5 is pushed into the inside of the document placing surface 2. The condition under which this slip occurs is as shown in the following equation (2).
[0078]
(Equation 2)

[0079]
Here, since Fb / Fa = tanA, if the angle A in the direction of the protrusion 5 is increased, Fb / Fa is increased. In the experiment in which the angle A was set to 15 degrees, the protruding portion 5 worked. That is, if the angle A is 15 degrees, the original is parallel to the original placing surface 2 and perpendicular to the original transport direction (the arrow Y direction in FIG. 10B) (FIG. In the case of manual insertion from the direction indicated by the arrow X in b), the protruding portion 5 is reliably pushed down into the document placing surface 2 by the document. For this reason, the original can be reliably detected without damaging the original and the protrusion 5. When the angle A is 15 degrees, Fb / Fa is 0.27. (Reference: The coefficient of friction between Teflon (registered trademark) or Teflon (registered trademark) and steel is 0.04.)
In addition, the component force Fb can be detected with a small force if the angle of the inclined surface of the protruding portion 5 is reduced. (See: description of FIG. 10A above.)
Also, FIG. 10C shows a direction in which the original is parallel to the original placing surface 2 and parallel to the original conveying direction (the arrow Y direction in FIG. 10C). It is a figure which shows dynamically the force which generate | occur | produces in the protrusion part 5 when it inserts by hand from the arrow S direction). Also in this case, the setting angle of the protruding portion 5 is A.
[0080]
In this case, as shown in FIG. 10C, the force Fp applied to the protruding portion 5 from the document becomes the component forces Fc and Fd. The component force Fc is a force that presses the protrusion 5 from the side. In addition, the document slides while being in contact with the protruding portion 5 due to the component force Fd, and the protruding portion 5 is pushed into the document placing surface 2. The condition under which this slip occurs is as shown in the following equation (3).
[0081]
[Equation 3]

[0082]
Here, since Fd / Fc = 1 / tanA, if the installation angle A of the protrusion 5 is reduced, Fd / Fc increases.
[0083]
Hereinafter, in any range of the installation angle A of the protruding portion 5, the original is parallel to the original placing surface 2 and perpendicular to the original transport direction (the arrow Y direction in FIG. 10B). When the document is manually inserted from an appropriate direction (arrow X direction in FIG. 10B), and when the document is parallel to the document placing surface 2 and in the document transport direction (arrow Y direction in FIG. 10C). It was examined whether or not the protruding portions 5 functioned properly when inserted by hand from a direction parallel to (the direction of arrow S in FIG. 10C). The results are shown in Table 1 below.
[0084]
[Table 1]

[0085]
The experiment conditions at this time were as follows: paper size: A4, number of sheets: 2, 64 g / m2 ² The material of the protrusion 5 is ABS. In the table, ○ indicates good and x indicates bad.
[0086]
From the results in Table 1 above, it can be seen that it is preferable that the installation angle of the protruding portion 5 in the movable detection unit 25 of the document detection sensor 20 be 15 to 75 degrees with respect to the document transport direction. This is because, when the installation angle A is too small, when a document is applied to the document detection sensor 20 from a direction perpendicular to the document conveyance direction (e.g., the front side of the main body), a force to push down the protruding portion 5 of the document detection sensor 20 is generated. Because it becomes weak. On the other hand, if the installation angle A is too large, the force of pushing down the protruding portion 5 of the document detection sensor 20 when the document is applied to the document detection sensor 20 from the document conveyance direction (the document is in the horizontal direction of the main body) becomes weak. It is considered to be.
[0087]
Further, as shown in FIGS. 2A and 2B, it is preferable that the protruding portion 5 of the movable detection unit 25 of the document detection sensor 20 be arranged within the range of the minimum fixed size width of the document guide 3. That is, when the pair of document guides 3 are at the position of the minimum size, it is preferable to provide the movable detection unit 25 between the pair of document guides 3. This makes it possible to reliably detect the presence or absence of a document having the minimum standard size and the document size. It goes without saying that all documents having a width equal to or larger than the minimum standard size width can be detected if they are smaller than the settable maximum size width of the document guide 3.
[0088]
Further, it is preferable that the protruding portion 5 of the document detection sensor 20 be set off the center portion of the document placing range (document placing surface 2) on the document tray 11. For example, when the user stands in front of the image forming apparatus 110 and the document transport direction is the left-right direction when viewed from the user, if the projecting portion 5 of the document detection sensor 20 is arranged at the back of the center of the document, Even when a document is inserted and placed on the document tray 11 while holding the center or the front by hand, the user's hand and the protruding portion 5 are less likely to collide with each other. Therefore, it is possible to prevent the user from being injured.
[0089]
A countermeasure for a raised document will be described below with reference to FIG. FIG. 5 is a diagram schematically illustrating a countermeasure for a raised document. As shown in FIG. 5, when a raised portion occurs in the document due to the folding of the document or the like, the document may not contact the protruding portion 5 and may not be detected by the document detection sensor 20. As a countermeasure, there is a method of increasing the height of the detecting portion of the protruding portion 5 of the document detection sensor 20 (the portion indicated by a dotted line in FIG. 5). In this case, the side surface 5c of the protruding portion 5 and the document can be further contacted. The nature becomes high. That is, the side face 5c of the protrusion 5 collides with the document, the protrusion 5 cannot function properly, and the possibility that the protrusion 5 or the document is damaged increases. However, even in such a case, the above problem can be avoided by using the configuration according to the present embodiment. That is, it is possible to prevent the protrusion 5 or the document from being damaged by the collision between the side surface 5c of the protrusion 5 and the document. Further, if the present invention is used, the protruding portion 5 can be provided higher than in the related art. This is because even if the protrusion 5 is set high, it is possible to prevent the damage to the protrusion 5 or the document.
[0090]
[Embodiment 2]
Another embodiment of the paper tray according to the present invention will be described below with reference to FIGS. 8, 9, and 11. FIG. For convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0091]
FIG. 9A is a diagram schematically illustrating another embodiment of the document detection sensor provided on the paper tray, and FIG. 9B is a cross-sectional view of FIG. FIGS. 9C and 9D are diagrams schematically showing a state in which a document hits the document detection sensor in FIG. 9A.
[0092]
As shown in FIG. 9A, the document detection sensor 20 according to the present embodiment is installed on the document tray 11 so as to be rotatable in the horizontal direction with respect to the document placing surface 2. More specifically, the document detection sensor 20 includes a rotating rotating disk 26 and a protrusion 5 projecting from the rotating disk 26 substantially perpendicularly to the rotating disk 26. The protruding portion 5 is provided apart from the rotation center of the rotating disk 26.
[0093]
In the present embodiment, the protruding portion 5 is provided so that its longitudinal direction is parallel to the diametrical direction of the rotating disk 26. However, the present invention is not limited to this. May be provided to be inclined with respect to the diametrical direction.
[0094]
Also, as shown in FIG. 9C, when the original is inserted and placed from the inside of the original placing surface 2, the original strikes the protruding portion 5, and the protruding portion 5 is pressed, and the original detecting sensor 20 moves the original detecting sensor 20. It rotates on the mounting surface 2. Then, the direction of the protruding portion 5 approaches the document insertion direction, and the document is efficiently pushed down.
[0095]
That is, for example, as shown in FIG. 9C, when the inserted document collides with the side surface 5c of the protrusion 5, the protrusion 5 does not normally function properly, and the protrusion 5 It is not pushed into the mounting surface 2. However, according to the document detection sensor 20 according to the present embodiment, when the inserted document collides with the side surface 5c of the protruding portion 5, the protruding portion 5 is pushed by the document, and the rotating disk 26 is placed on the document. It rotates horizontally on the placement surface 2 (see FIG. 9D). Then, when the rotating disk 26 rotates and the document comes into contact with the slope (5a or 5b) of the protruding portion 5, the protruding portion 5 is pushed into the document placing surface 2 (the inside of the rotating disk 26) by the document. Therefore, even when the document collides with the side surface 5c of the protrusion 5 of the document detection sensor 20, it is possible to prevent the document or the protrusion 5 from being damaged and to reliably detect the document.
[0096]
Note that a bearing (not shown) may be provided near the lower rotation axis (center of rotation) on the lower side of the rotating disk 26 in order to smooth the rotation of the rotating disk 26.
[0097]
Further, it is preferable that the protrusion 5 is set so as to return to a predetermined direction (predetermined position) on the document placing surface 2. That is, it is preferable that the protruding portion 5 of the document detection sensor 20 be set to face a predetermined direction when not in contact with the document.
[0098]
Specifically, for example, when the document placing surface 2 is inclined, a weight is attached to the rotating disk 26 of the document detection sensor 20, and the direction in which the weight is attached is directed downward is used. However, the present invention is not limited to this method. In addition to the weight, as means for returning the position of the protruding portion 5 to a predetermined position, for example, an elastic body such as a spring, a motor, or the like can be used.
[0099]
This can prevent the user from being injured. That is, for example, when the original is placed and the protruding portion 5 is located on the near side as viewed from the user, and the protruding portion 5 is left as it is and the original is placed again, the user's hand is Although there is a problem that it is easy to collide with No. 5, this problem can be avoided according to the above configuration.
[0100]
FIG. 8A schematically shows another embodiment of a document detection sensor provided on a paper tray. FIG. 8B is a cross-sectional view of FIG. As shown in FIGS. 8A and 8B, the protruding portion 5 is attached to a rotating disk 26 provided on the original placing surface 2 so as to be rotatable in the horizontal direction with respect to the original placing surface 2. By setting, the direction of the protruding portion 5 of the document detection sensor 20 can be set by hand. This allows the user to manually set the installation direction of the protrusion 5 of the document detection sensor 20 as appropriate.
[0101]
Further, for example, an elastic member (not shown) such as a spring may be used to move the projecting portion 5 of the document detection sensor 20 up and down.
[0102]
FIG. 11 is a diagram illustrating the manual paper feed tray 30 provided with the paper detection sensor 35. As shown in FIG. 11, the manual paper feed tray 30 includes a paper mounting surface 32, a paper feed guide 33, and a paper detection sensor 35. The paper placement surface 32 has the same configuration as the above-described original placement surface 2, the paper feed guide 33 has the same configuration as the above-described original guide 3, and the paper detection sensor 35 has the same configuration as the above-described original detection sensor 20. That is, the operations, functions, and effects described above with respect to the document tray 11 provided with the document detection sensor 20 can be applied to the manual paper feed tray 30 provided with the paper detection sensor 35. That is, even when the paper is inserted and placed in the manual paper feed tray 30 in a direction perpendicular to the paper feed conveyance direction, or when the paper is inserted and placed in the paper feed conveyance direction, the paper detection sensor 35 may be damaged, In addition, the paper can be prevented from being damaged. In addition, since the paper detection sensor 35 functions reliably, the paper can be reliably detected. Further, when the paper detection sensor 35 is provided so as to be rotatable horizontally with respect to the paper mounting surface 32, similarly to the case of the original tray 11, for example, the paper is held in the hand and When inserting the paper, the paper detection sensor 35 is rotated, so that the paper detection sensor 35 can be prevented from being damaged or damaged even when the paper is inserted (placed) from any direction. Can be.
[0103]
The present invention is not limited to the embodiments described above, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.
[0104]
【The invention's effect】
As described above, the paper tray of the present invention includes a paper mounting surface for mounting a document or paper, and a detection unit provided on the paper mounting surface for detecting the document or paper. The detection unit is a contact-type detection sensor including a movable detection unit having a protrusion that projects substantially perpendicularly to the sheet placement surface, and the protrusion in the movable detection unit is The paper is placed on the paper mounting surface such that its installation direction is not substantially parallel to the original or paper transport direction and is not substantially vertical.
[0105]
Therefore, even when a document or the like is inserted and placed on the paper tray according to the present invention, for example, from a direction perpendicular to the transport direction of the document or the like, or when the document or the like is inserted and placed from the transport direction of the document, the detection is performed. This has the effect of preventing damage to the protruding portion of the portion, or damage to the original or the like. In addition, since the protruding portion functions reliably, it is possible to reliably detect a document or the like.
[0106]
Further, as described above, the paper tray of the present invention includes a paper mounting surface for mounting a document or paper, and a detection unit provided on the paper mounting surface for detecting the document or paper. The detection unit is a contact-type detection sensor including a movable detection unit having a protrusion that projects substantially perpendicularly to the sheet placement surface. The protruding portion is configured to be provided on the paper mounting surface so as to be rotatable in a horizontal direction with respect to the paper mounting surface.
[0107]
Therefore, for example, when a document or the like is inserted into the paper tray while being held in the hand, the detection unit rotates, and therefore, even when the document or the like is inserted (placed) from any direction, This has the effect of preventing damage to the protruding portion in the detection section and damage to the original and the like. Further, since the protruding portion functions reliably, it is possible to reliably detect a document or the like.
[0108]
Further, the paper tray of the present invention can be used for an automatic document feeder and an image forming apparatus. Therefore, it is possible to obtain an automatic document feeder and an image forming apparatus that can surely detect a document or the like while preventing the protrusion or the document or the like in the detection unit from being damaged.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically illustrating a structure of a document tray according to an embodiment.
FIG. 2A is a diagram of the structure of the document tray according to the embodiment as viewed from above, and FIG. 2B is a diagram of FIG. 2A as viewed from the direction of arrow Z.
FIG. 3 is a cross-sectional view schematically illustrating a structure of the automatic document feeder according to the embodiment.
FIGS. 4A and 4B are diagrams schematically illustrating a configuration example of a document detection sensor according to the embodiment and an operation thereof;
FIG. 5 is a diagram schematically illustrating a countermeasure to a raised document.
FIG. 6 is a diagram schematically showing the structure of the image forming apparatus according to the embodiment.
FIGS. 7A and 7B are diagrams schematically illustrating another example of the shape of the protruding portion in the movable detection unit according to the embodiment.
8A is a schematic diagram illustrating another embodiment of a document detection sensor provided on a paper tray, and FIG. 8B is a cross-sectional view of FIG.
9A is a diagram schematically illustrating another embodiment of a document detection sensor provided on a paper tray, FIG. 9B is a cross-sectional view of FIG. 9A, and FIGS. FIGS. 4A and 4B are diagrams schematically showing a state in which a document hits the document detection sensor in FIG.
FIG. 10A is a diagram dynamically showing a force generated in a protrusion when a document is manually inserted from a direction parallel to the document placing surface, and FIG. FIG. 9C is a diagram dynamically showing a force generated in the protruding portion when is manually inserted from a direction parallel to the document placing surface and perpendicular to the document transport direction. FIG. 9 is a diagram dynamically illustrating a force generated in a protruding portion when a document is manually inserted from a direction parallel to the document placing surface and parallel to the document transport direction.
FIG. 11 is a diagram illustrating a manual paper feed tray provided with a paper detection sensor according to the embodiment;
FIG. 12A is a top view of a document tray provided in a conventional digital copying machine, and FIG. 12B is a perspective view of FIG.
[Explanation of symbols]
2 Original loading surface (paper loading surface)
5 Projection
5a Slope of protrusion
5b Slope of protrusion
5c Side of the protrusion
10 Automatic Document Feeder
11 Document tray (paper tray)
20 Document detection sensor (detection unit)
25 Movable detector
30 Paper tray (paper tray)
32 Paper loading surface
35 Paper detection sensor (detection unit)
110 Image Forming Apparatus

Claims (10)

In a paper tray provided in an automatic document feeder that conveys a document to a document reading unit or a paper feeding device that feeds a sheet to an image forming unit,
The paper tray includes a paper mounting surface for mounting a document or paper, and a detection unit provided on the paper mounting surface for detecting the document or the paper,
The detection unit is a contact-type detection sensor including a movable detection unit having a protrusion that protrudes substantially perpendicularly to the sheet placement surface,
The protruding portion of the movable detection portion is provided on the sheet mounting surface such that its installation direction is not substantially parallel to the document or sheet conveyance direction, and is not substantially perpendicular to the document conveyance direction. And the paper tray. In a paper tray provided in an automatic document feeder that conveys a document to a document reading unit or a paper feeding device that feeds a sheet to an image forming unit,
The paper tray includes a paper mounting surface for mounting a document or paper, and a detection unit provided on the paper mounting surface for detecting the document or the paper,
The detection unit is a contact-type detection sensor including a movable detection unit having a protrusion that protrudes substantially perpendicularly to the sheet placement surface,
The paper tray according to claim 1, wherein the protrusion in the movable detection unit is provided on the paper mounting surface so as to be rotatable in a horizontal direction with respect to the paper mounting surface. 2. The protruding part of the movable detection part is provided such that its installation direction is at an angle of 15 to 75 degrees with respect to a document or paper transport direction. Paper tray. The paper tray according to claim 1, wherein a shape of the protrusion in the movable detection unit is substantially triangular. 5. The paper tray according to claim 4, wherein the slope of the slope of the substantially triangular protrusion is formed gently. The sheet according to claim 1, wherein at least one of the protrusions of the movable detection unit is provided within a range of a minimum width of a sheet of a standard size on the sheet mounting surface. tray. The paper tray according to claim 1, wherein the protruding portion of the movable detection unit is provided off a central portion of the paper mounting surface. 3. The paper tray according to claim 2, wherein an installation direction of the protruding portion in the movable detection unit is set so as to face a predetermined direction when not in contact with a document or paper. An automatic document feeder comprising the paper tray according to claim 1. An image forming apparatus comprising the paper tray according to any one of claims 1 to 8.

Images