JP2002338084A - Image forming device - Google Patents

Image forming device

Info

Publication number
JP2002338084A
JP2002338084A JP2001143545A JP2001143545A JP2002338084A JP 2002338084 A JP2002338084 A JP 2002338084A JP 2001143545 A JP2001143545 A JP 2001143545A JP 2001143545 A JP2001143545 A JP 2001143545A JP 2002338084 A JP2002338084 A JP 2002338084A
Authority
JP
Japan
Prior art keywords
sheet
image forming
unit
image
leading
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
JP2001143545A
Other languages
Japanese (ja)
Inventor
Toshiro Tomono
俊郎 友野
Original Assignee
Canon Inc
キヤノン株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc, キヤノン株式会社 filed Critical Canon Inc
Priority to JP2001143545A priority Critical patent/JP2002338084A/en
Publication of JP2002338084A publication Critical patent/JP2002338084A/en
Withdrawn legal-status Critical Current

Links

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device allowing obtaining of high grade images by making margins of front and rear ends of a first surface and a second surface coincide each other. SOLUTION: In this image forming device having pickup rollers (paper feeding means) 12a and 12b, image formation means (photosensitive drums 5Y, 5M, 5C, 5BK and developing devices 7Y, 7M, 7C, 7BK, etc.), a fixing device (fixing means) 17, a flapper (paper discharging direction branch means) 17 and a sheet reversing roller (sheet reverse means) 21, a carrier roller (sheet carrier means) 50, a JAM detecting sensor (sheet tip/rear end detection means) 51, a storage means for storing detected time and a paper refeeding means, contraction amount of the sheet after fixing the images of the first surface is calculated from signals of the JAM detecting sensor 51 of the first surface and the second surface before the formation of images, and image formation starting and finishing time for the second surface are controlled so as to make the same margins at tip/rear ends as that of the first surface.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【0001】[0001]
【発明の属する技術分野】本発明は、シート搬送手段を
備える画像形成装置に関する。
[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus having a sheet conveying means.
【0002】[0002]
【従来の技術】従来、両面コピー又はプリントを行うと
きは、工場出荷時にカセット上にある紙位置と画像書き
出しタイミングを調整して前後左右余白が或る一定値以
内になるように調整されている。
2. Description of the Related Art Conventionally, when performing double-sided copying or printing, the paper position on a cassette and the image writing timing at the time of shipment from a factory are adjusted so that the front, rear, left and right margins are within a certain fixed value. .
【0003】[0003]
【発明が解決しようとする課題】しかしながら、2面目
をプリント又はコピーするときは、一度定着器をシート
が通過すると紙が縮むため、1面目と同じタイミングで
画像を書き込むと後端の余白が小さくなってしまう。2
面目は1面目より露光時間を短くする対策を施した製品
もあるが、シート厚さや1面目の画像によって縮み量が
異なるため、厳密に1面目と2面目の画像の先後端余白
を一致させることは困難であった。
However, when printing or copying the second side, the paper shrinks once the sheet passes through the fixing device. Therefore, if an image is written at the same timing as the first side, the margin at the rear end becomes small. turn into. 2
Some products have a measure to shorten the exposure time on the first side, but the shrinkage varies depending on the sheet thickness and the image on the first side. Was difficult.
【0004】本発明は上記問題に鑑みてなされたもの
で、その目的とする処は、1面目と2面目の前後端の余
白を一致させて高品位な画像を得ることができる画像形
成装置を提供することにある。
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an image forming apparatus capable of obtaining a high-quality image by matching the margins at the front and rear ends of the first and second surfaces. To provide.
【0005】[0005]
【課題を解決するための手段】上記目的を達成するた
め、本発明は、紙長さが管理されたシートと、シート搬
送手段と、該シート搬送手段の下流にシート先後端を検
知するシート先後端検知手段と、シート先後端を検出し
た時間を記憶する記憶手段と、紙長さが管理された標準
シートを搬送したときの前記記憶手段の時間からユーザ
ーが使用するシート長さを演算する演算手段を含んで画
像形成装置を構成したことを特徴とする。
SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a sheet having a controlled paper length, a sheet conveying means, and a sheet front and rear end detecting a sheet front and rear end downstream of the sheet conveying means. Edge detection means, storage means for storing the time at which the leading and trailing edges of the sheet are detected, and calculation for calculating the sheet length used by the user from the time of the storage means when a standard sheet whose paper length is managed is conveyed The image forming apparatus is configured to include means.
【0006】請求項2記載の発明は、給紙手段と、画像
形成手段と、定着手段と、排紙方向分岐手段及びシート
反転手段と、シート搬送手段と、シート先後端検知手段
と、検出した時間を記憶する記憶手段と、再給紙手段を
有する画像形成装置において、画像形成前の1面目と2
面目のシート先後端検知手段の信号から1面目画像を定
着後のシートの縮み量を算出し、 先後端余白を1面目と
同一にするために2面目の画像形成開始と終了時間を制
御することを特徴とする。
According to a second aspect of the present invention, a sheet feeding unit, an image forming unit, a fixing unit, a sheet discharging direction branching unit and a sheet reversing unit, a sheet conveying unit, a sheet leading and trailing end detecting unit are detected. In an image forming apparatus having a storage unit for storing time and a sheet re-feeding unit, the first and second surfaces before image formation are
Calculating the amount of shrinkage of the sheet after fixing the image of the first side from the signal of the sheet front and rear end detection means of the first side, and controlling the image formation start and end times of the second side to make the front and rear end margins the same as the first side; It is characterized by.
【0007】請求項3記載の発明は、請求項1又は2記
載の発明において、前記シート先後端検知手段をJAM
検知センサー又はOHT検知センサーで構成したことを
特徴とする。
According to a third aspect of the present invention, in the first or second aspect, the sheet leading and trailing end detecting means is a JAM.
It is characterized by comprising a detection sensor or an OHT detection sensor.
【0008】[0008]
【発明の実施の形態】以下に本発明の実施の形態を添付
図面に基づいて説明する。
Embodiments of the present invention will be described below with reference to the accompanying drawings.
【0009】<実施の形態1>図1は本発明に係る画像
形成装置(フルカラー複写機)の断面図であり、同図に
おいて、1は複写機本体であり、その上部には、原稿を
読取位置まで自動給送する自動原稿給送装置2が搭載さ
れている。又、複写機本体1内には、装置上部にデジタ
ル画像リーダ部3、装置下部にデジタル画像プリンタ部
4を装備されている。
<First Embodiment> FIG. 1 is a sectional view of an image forming apparatus (full color copying machine) according to the present invention. In FIG. An automatic document feeder 2 that automatically feeds to a position is mounted. Further, in the copying machine main body 1, a digital image reader section 3 is provided at the upper part of the apparatus, and a digital image printer section 4 is provided at the lower part of the apparatus.
【0010】上記自動原稿搬送装置2に原稿が載置さ
れ、スタートボタンが押されると、カセット11a,1
1bからシートが給紙される。原稿台ガラス上にセット
された原稿は、読取手段としてのデジタル画像リーダ部
により光照射されてその反射光がCCD等の光電変換素
子に集光されて電気信号に変換されて画像信号が得られ
る。この画像信号は、不図示の増幅回路を経て不図示の
ビデオ処理ユニットにて処理された後、画像形成手段と
してのデジタル画像プリンタ部へ転送される。
When a document is placed on the automatic document feeder 2 and the start button is pressed, the cassettes 11a, 1
The sheet is fed from 1b. The original set on the platen glass is irradiated with light by a digital image reader unit as reading means, and the reflected light is condensed on a photoelectric conversion element such as a CCD and converted into an electric signal to obtain an image signal. . This image signal is processed by a video processing unit (not shown) through an amplification circuit (not shown), and then transferred to a digital image printer unit as image forming means.
【0011】又、5Y,5M,5C,5Bkは像担持体
としての感光ドラムであり、その周囲には帯電器、現像
器7Y,7M,7C,7Bk、転写帯電器8Y,8M,
8C,8Bk、クリーニング器9Y,9M,9C,9B
k等のプロセス手段がそれぞれ配設されている。10は
レーザー露光光学系であり、前記デジタル画像リーダ部
からの画像信号はレーザー出力部にて光信号に変換さ
れ、該変換されたレーザー光はポリゴンミラーで反射さ
れ、ミラーを経て各感光ドラム5Y,5M,5C,5B
kの周面に投影される。
Reference numerals 5Y, 5M, 5C, and 5Bk denote photosensitive drums as image carriers, around which charging devices, developing devices 7Y, 7M, 7C, 7Bk, and transfer charging devices 8Y, 8M,
8C, 8Bk, cleaning units 9Y, 9M, 9C, 9B
k and other process means are provided. Reference numeral 10 denotes a laser exposure optical system. An image signal from the digital image reader unit is converted into an optical signal by a laser output unit, and the converted laser light is reflected by a polygon mirror, and passes through the mirror. , 5M, 5C, 5B
It is projected on the circumference of k.
【0012】画像形成時には、上記各感光ドラム5Y,
5M,5C,5Bkは帯電器により予め帯電されてお
り、前記レーザー露光光学系10により露光されて静電
潜像が形成され、各静電潜像は現像器7Y,7M,7
C,7Bkによりイエロー、マゼンタ、シアン、ブラッ
クの各色トナーが付与されてトナー像が形成される。
At the time of image formation, each of the photosensitive drums 5Y, 5Y
5M, 5C and 5Bk are charged in advance by a charger, and are exposed by the laser exposure optical system 10 to form an electrostatic latent image. Each electrostatic latent image is developed by a developing unit 7Y, 7M, 7
C, 7Bk is applied with yellow, magenta, cyan, and black toners to form toner images.
【0013】装置下部に装備されたカセット11a,1
1bよりピックアップローラ12a,12bにより送り
されたシートは、リタードローラ対により1枚ずつ分離
搬送され、停止しているレジストローラ対14に搬送さ
れて斜行が補正される。尚、手差しトレイ15より送り
込まれたシートも同様に停止しているレジストローラ対
14に搬送されて斜行が補正される。
Cassettes 11a, 1 mounted at the lower part of the apparatus
Sheets fed from pickup rollers 1b by pickup rollers 12a and 12b are separated and conveyed one by one by a pair of retard rollers, and conveyed to a stopped registration roller pair 14 to correct skew. The sheet fed from the manual feed tray 15 is similarly conveyed to the stopped registration roller pair 14 to correct the skew.
【0014】上記シートは、レジストローラ対14を駆
動させて所定のタイミングで転写ベルト16上に載置さ
れて搬送され、該転写ベルト16を介して対向する各感
光ドラム5Y,5M,5C,5Bkと転写帯電器8Y,
8M,8C,8Bk間を通過する際に各色トナー像がそ
れぞれ転写される。尚、画像転写後に各感光ドラム5
Y,5M,5C,5Bkに残留するトナーは、クリーニ
ング器9Y,9M,9C,9Bkによって除去され、ト
ナーが除去された各感光ドラム5Y,5M,5C,5B
kは次の画像形成に備えられる。
The above-mentioned sheet is placed on a transfer belt 16 at a predetermined timing by driving a pair of registration rollers 14 and conveyed, and the photosensitive drums 5Y, 5M, 5C, 5Bk facing each other via the transfer belt 16 are conveyed. And the transfer charger 8Y,
When passing between 8M, 8C and 8Bk, the toner images of the respective colors are respectively transferred. After image transfer, each photosensitive drum 5
The toner remaining on Y, 5M, 5C, 5Bk is removed by cleaning units 9Y, 9M, 9C, 9Bk, and the respective photosensitive drums 5Y, 5M, 5C, 5B from which the toner has been removed.
k is prepared for the next image formation.
【0015】17は定着装置であり、この定着装置17
はローラ対間を通過するシートに熱及び圧力を印加する
ことによってトナー像をシート上に定着させる。
Reference numeral 17 denotes a fixing device.
Fixes the toner image on the sheet by applying heat and pressure to the sheet passing between the roller pairs.
【0016】そして、画像定着後のシートは、フラッパ
18により搬送路を切り換えられ、片面のみの画像形成
であれば、排紙ローラ対19に向かい、両面搬送する場
合は反転ローラ20へ向かい、反転ローラ21で所定の
タイミングで搬送された後、反転ローラ21が逆転する
ことによってパスBに搬送され、その後、給紙パス40
と合流してレジストローラ対14に搬送される。
The conveyance path of the sheet after the image is fixed is switched by the flapper 18. If the image is formed on one side only, the sheet goes to the discharge roller pair 19. After being conveyed at a predetermined timing by the roller 21, the sheet is conveyed to the path B by the reverse rotation of the reversing roller 21.
And is conveyed to the pair of registration rollers 14.
【0017】次に画像の余白合わせ方法について説明す
る。
Next, a method of adjusting the margins of an image will be described.
【0018】初期状態では、図2に示すように、左右と
先後端の余白が合っていない場合がある。それは、カセ
ット内の紙位置のズレ、露光位置のズレがある。それら
は多くのメカ部品のバラツキが重なり合ったものである
ため、製品を工場出荷時に調整している。
In the initial state, as shown in FIG. 2, there are cases where the margins of the left, right, front and rear ends do not match. There are deviations in the paper position in the cassette and deviations in the exposure position. The products are adjusted at the time of shipment from the factory because the variations of many mechanical parts overlap.
【0019】具体的には、先後端余白は出力画像から先
後余白を測定してレーザー又はLEDの発光開始と終了
時間を制御している。例えば、先後端余白の規格が3m
mに対して、実際には、 先端余白:3.6mm(L1 ) 後端余白:2.4mm(L2 ) 左余白:3.2mm(S1 ) 右余白:2.8mm(S2 ) であったとすると、400dpiの製品であれば1do
t0.063mmであるため、先端余白は−10dot
ずらし、 後端余白は+10dot 左余白は−3dot 右余白は+3dot ずらして規格3mmに合わせ込む。
Specifically, the leading and trailing margins are measured from the output image to control the start and end times of laser or LED emission. For example, the standard of the leading and trailing margins is 3m
For m, actually, the front margin: 3.6 mm (L 1 ), the rear margin: 2.4 mm (L 2 ), the left margin: 3.2 mm (S 1 ), and the right margin: 2.8 mm (S 2 ). If the product is 400 dpi, 1 do
Since t is 0.063 mm, the top margin is -10 dots.
Shift the trailing margin by +10 dots. Left margin is -3 dots. Right margin is +3 dots.
【0020】2面目の余白は、従来、1面目と同様に行
っていたが、近年シートの種類が増え、画像もグラフ印
刷等の低濃度画像から写真等の高濃度画像等、ユーザー
が印刷する画像も多岐に亘る。
Conventionally, the margin of the second side is set in the same manner as that of the first side. However, in recent years, the number of types of sheets has increased, and the user prints images from low-density images such as graph printing to high-density images such as photographs. The images are also diverse.
【0021】トナーが印字されたシートを定着すると該
シートは縮むが、シートの種類、印字される画像によっ
て縮み量が異なる。そのため、2面目の先後端余白を工
場出荷時に調整しても、市場で使うユーザーが工場出荷
時に用いたシートと異なったシートを用いると余白がず
れてしまう。
When a sheet on which toner is printed is fixed, the sheet shrinks, but the amount of shrinkage differs depending on the type of sheet and the image to be printed. Therefore, even if the front and rear margins of the second surface are adjusted at the time of shipment from the factory, the margins are shifted if a user used in the market uses a sheet different from the sheet used at the time of shipment from the factory.
【0022】そこで、本実施の形態では、1面目は従来
と同じように工場出荷時に調整し、2面目は紙の縮み量
を検出して先後端余白を自動調整するようにしている。
Therefore, in the present embodiment, the first side is adjusted at the time of shipment from the factory as in the prior art, and the second side is configured to automatically adjust the leading and trailing margins by detecting the amount of paper shrinkage.
【0023】1面目が画像形成された画像は、両面パス
の搬送ローラ50で搬送される。搬送ローラ50の下流
に設けられたJAM検知センサー51を利用して搬送ロ
ーラ50から送られるシートの先後端を検知する。搬送
ローラ50の外径φD、回転数n(rps)、シートの
サイズは予め分かっている。尚、図3(a),(b)に
JAM検知センサー51によるシートの先後端の検出を
示す。
The image on which the first surface is formed is conveyed by the conveying roller 50 of a two-sided pass. The front and rear edges of the sheet sent from the transport roller 50 are detected using a JAM detection sensor 51 provided downstream of the transport roller 50. The outer diameter φD of the conveying roller 50, the number of rotations n (rps), and the size of the sheet are known in advance. 3A and 3B show the detection of the leading and trailing edges of the sheet by the JAM detection sensor 51.
【0024】従って、先後端の検出時間をTとしてA3
サイズのシートを流した場合の縮み量は、 縮み量=420(A3サイズ)−T・π・D・n …(1) となる。例えば、0.5mmとする。
Therefore, if the detection time of the front and rear ends is T, A3
The shrinkage amount when a sheet of a size is passed is as follows: shrinkage amount = 420 (A3 size) −T · π · D · n (1) For example, it is 0.5 mm.
【0025】この縮み量を2で割って画像形成の書き出
しタイミングを4dot分遅らせて終了タイミングを4
dot早めれば、先後端余白が3mmになる。尚、紙先
後端検知手段はJAM検知センサーだけでなく、OHT
検出センサー等の非接触式のものでも良い。又、搬送ロ
ーラも画像形成開始タイミングに間に合えば、レジスト
ローラを用いても良い。
This shrinkage amount is divided by 2 to delay the writing start timing of the image formation by 4 dots and set the end timing to 4 dots.
If the dot is advanced, the leading and trailing edge margins become 3 mm. The paper trailing edge detection means is not only a JAM detection sensor but also an OHT
A non-contact type such as a detection sensor may be used. Also, a registration roller may be used for the transport roller as long as the image forming start timing is reached.
【0026】<実施の形態2>次に、本発明の実施の形
態2として基準シートを用いる方法について述べる。
<Second Embodiment> Next, a method using a reference sheet as a second embodiment of the present invention will be described.
【0027】搬送ローラの外径は製造上もばらつき、
又、大量通紙中に外径が削れて設計称呼値とズレている
のが実情である。より高精度に余白を合わせるために
は、ローラ外径起因のバラツキを抑える必要がある。
The outer diameter of the transport roller also varies in manufacturing,
Further, the fact is that the outer diameter is cut off during mass paper passing, and the actual diameter is deviated from the design nominal value. In order to adjust the margins with higher precision, it is necessary to suppress variations caused by the outer diameter of the roller.
【0028】そこで、予め搬送方向の長さLが厳密に管
理されている基準シートを通紙してシート先後端の検出
時間を測定する。そのとき、ローラ径Dは、 D=L/(T・π・n) …(2) と厳密に算出することができる。
Therefore, a reference sheet whose length L in the transport direction is strictly controlled in advance is passed, and the detection time of the leading edge and the trailing edge of the sheet is measured. At this time, the roller diameter D can be strictly calculated as follows: D = L / (T · π · n) (2)
【0029】(2)式によって算出されたローラ径Dを
前記(2)式に代入すれば、ローラ外径起因のバラツキ
を抑えることができる。又、市場のローラ摩耗により余
白がずれてきた場合は、上記作業を行うことによって補
正することができる。尚、基準シートとしては、金属板
又は樹脂シートが適当である。
By substituting the roller diameter D calculated by the equation (2) into the equation (2), it is possible to suppress variations caused by the outer diameter of the roller. If the margin is shifted due to the wear of the roller in the market, it can be corrected by performing the above operation. Note that a metal plate or a resin sheet is appropriate as the reference sheet.
【0030】[0030]
【発明の効果】以上の説明で明らかなように、本発明に
よれば、給紙手段と、画像形成手段と、定着手段と、排
紙方向分岐手段及びシート反転手段と、シート搬送手段
と、シート先後端検知手段と、検出した時間を記憶する
記憶手段と、再給紙手段を有する画像形成装置におい
て、画像形成前の1面目と2面目のシート先後端検知手
段の信号から1面目画像を定着後のシートの縮み量を算
出し、 先後端余白を1面目と同一にするために2面目の
画像形成開始と終了時間を制御するようにしたため、1
面目と2面目の前後端の余白を一致させて高品位な画像
を得ることができる。
As is apparent from the above description, according to the present invention, the sheet feeding means, the image forming means, the fixing means, the sheet discharging direction branching means and the sheet reversing means, the sheet conveying means, In an image forming apparatus having a sheet leading and trailing edge detecting means, a storage means for storing the detected time, and a sheet re-feeding means, a first image is formed from a signal from the first and second sheet leading and trailing edge detecting means before image formation. The amount of shrinkage of the sheet after fixing is calculated, and the start and end times of image formation on the second side are controlled to make the leading and trailing margins equal to the first side.
A high-quality image can be obtained by matching the margins at the front and rear ends of the surface and the second surface.
【図面の簡単な説明】[Brief description of the drawings]
【図1】本発明に係る画像形成装置(フルカラー複写
機)の断面図である。
FIG. 1 is a sectional view of an image forming apparatus (full-color copying machine) according to the present invention.
【図2】画像の余白合わせ方法を示す図である。FIG. 2 is a diagram showing a method of adjusting a margin of an image.
【図3】JAM検知センサーによるシートの先後端の検
出方法を示す図である。
FIG. 3 is a diagram illustrating a method of detecting the leading and trailing edges of a sheet using a JAM detection sensor.
【符号の説明】[Explanation of symbols]
1 複写機本体 5Y,5M,5C,5Bk 感光ドラム(画像形成手
段) 7Y,7M,7C,7Bk 現像器(画像形成手段) 8Y,8M,8C,8Bk 転写帯電器(画像形成手
段) 12a,12b ピックアップローラ(給紙手段) 14 レジストローラ対 17 定着装置(定着手段) 18 フラッパ(排紙方向分岐手段) 21 反転ローラ(シート反転手段) 50 搬送ローラ(シート搬送手段) 51 JAM検知センサー(シート先部後端
検知手段)
1 Copier main body 5Y, 5M, 5C, 5Bk Photosensitive drum (image forming means) 7Y, 7M, 7C, 7Bk Developing device (image forming means) 8Y, 8M, 8C, 8Bk Transfer charger (image forming means) 12a, 12b Pickup roller (feeding means) 14 Registration roller pair 17 Fixing device (fixing means) 18 Flapper (discharge direction branching means) 21 Reverse roller (sheet reversing means) 50 Transport roller (sheet transporting means) 51 JAM detection sensor (sheet end) Rear end detection means)
フロントページの続き Fターム(参考) 2H027 DC06 DC10 DC14 ED04 2H028 BA06 BA09 BA12 BB06 2H072 AA17 AA23 AA32 BA03 BA12 CA01 CB01 CB03 JA02 3F048 AA03 AA05 AB01 BA07 BB02 CC02 CC03 CC04 CC11 DA06 DB12 DC00 EB37 3F049 AA10 DA12 LA03 LA07 LB03Continued on front page F term (reference) 2H027 DC06 DC10 DC14 ED04 2H028 BA06 BA09 BA12 BB06 2H072 AA17 AA23 AA32 BA03 BA12 CA01 CB01 CB03 JA02 3F048 AA03 AA05 AB01 BA07 BB02 CC02 CC03 CC04 CC11 DA06 DB12 DC00 LA03

Claims (3)

    【特許請求の範囲】[Claims]
  1. 【請求項1】 紙長さが管理されたシートと、シート搬
    送手段と、該シート搬送手段の下流にシート先後端を検
    知するシート先後端検知手段と、シート先後端を検出し
    た時間を記憶する記憶手段と、紙長さが管理された標準
    シートを搬送したときの前記記憶手段の時間からユーザ
    ーが使用するシート長さを演算する演算手段を有するこ
    とを特徴とする画像形成装置。
    1. A sheet having a controlled paper length, a sheet transporting means, a sheet leading and trailing edge detecting means for detecting a sheet leading and trailing edge downstream of the sheet transporting means, and a time at which the sheet leading and trailing edge is detected. An image forming apparatus comprising: a storage unit; and a calculation unit configured to calculate a sheet length used by a user from a time of the storage unit when a standard sheet whose paper length is managed is conveyed.
  2. 【請求項2】 給紙手段と、画像形成手段と、定着手段
    と、排紙方向分岐手段及びシート反転手段と、シート搬
    送手段と、シート先後端検知手段と、検出した時間を記
    憶する記憶手段と、再給紙手段を有する画像形成装置に
    おいて、 画像形成前の1面目と2面目のシート先後端検知手段の
    信号から1面目画像を定着後のシートの縮み量を算出
    し、 先後端余白を1面目と同一にするために2面目の画
    像形成開始と終了時間を制御することを特徴とする画像
    形成装置。
    2. A sheet feeding unit, an image forming unit, a fixing unit, a sheet discharging direction branching unit and a sheet reversing unit, a sheet conveying unit, a sheet leading and trailing end detecting unit, and a storage unit for storing a detected time. In the image forming apparatus having the sheet re-feeding means, the shrinkage amount of the sheet after fixing the first image is calculated from the signals of the first and second sheet leading and trailing edge detecting means before image formation, and the leading and trailing edge margins are calculated. An image forming apparatus characterized in that the start and end times of image formation on the second surface are controlled so as to be the same as the first surface.
  3. 【請求項3】 前記シート先後端検知手段をJAM検知
    センサー又はOHT検知センサーで構成したことを特徴
    とする請求項1又は2記載の画像形成装置。
    3. The image forming apparatus according to claim 1, wherein said sheet leading and trailing edge detecting means comprises a JAM detecting sensor or an OHT detecting sensor.
JP2001143545A 2001-05-14 2001-05-14 Image forming device Withdrawn JP2002338084A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2001143545A JP2002338084A (en) 2001-05-14 2001-05-14 Image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2001143545A JP2002338084A (en) 2001-05-14 2001-05-14 Image forming device

Publications (1)

Publication Number Publication Date
JP2002338084A true JP2002338084A (en) 2002-11-27

Family

ID=18989679

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2001143545A Withdrawn JP2002338084A (en) 2001-05-14 2001-05-14 Image forming device

Country Status (1)

Country Link
JP (1) JP2002338084A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006003679A (en) * 2004-05-18 2006-01-05 Ricoh Co Ltd Image forming method and image forming apparatus
JP2009265286A (en) * 2008-04-24 2009-11-12 Oki Data Corp Image forming device and image forming method thereof
US7792479B2 (en) 2005-05-27 2010-09-07 Canon Kabushiki Kaisha Image forming apparatus with error correction for length of transfer sheet
JP2010241600A (en) * 2009-03-18 2010-10-28 Ricoh Co Ltd To-be-transferred object length measuring device, image forming device using the same, and computer program

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006003679A (en) * 2004-05-18 2006-01-05 Ricoh Co Ltd Image forming method and image forming apparatus
JP4672291B2 (en) * 2004-05-18 2011-04-20 株式会社リコー Image forming apparatus
US7792479B2 (en) 2005-05-27 2010-09-07 Canon Kabushiki Kaisha Image forming apparatus with error correction for length of transfer sheet
JP2009265286A (en) * 2008-04-24 2009-11-12 Oki Data Corp Image forming device and image forming method thereof
JP4677006B2 (en) * 2008-04-24 2011-04-27 株式会社沖データ Image forming apparatus and image forming method
US8103180B2 (en) 2008-04-24 2012-01-24 Oki Data Corporation Image forming device and image forming method thereof
JP2010241600A (en) * 2009-03-18 2010-10-28 Ricoh Co Ltd To-be-transferred object length measuring device, image forming device using the same, and computer program

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