JPH04310976A - Image forming device - Google Patents

Image forming device

Info

Publication number
JPH04310976A
JPH04310976A JP3077505A JP7750591A JPH04310976A JP H04310976 A JPH04310976 A JP H04310976A JP 3077505 A JP3077505 A JP 3077505A JP 7750591 A JP7750591 A JP 7750591A JP H04310976 A JPH04310976 A JP H04310976A
Authority
JP
Japan
Prior art keywords
image
developing
bias
scanning
exposure
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.)
Pending
Application number
JP3077505A
Other languages
Japanese (ja)
Inventor
Hiroyuki Maeda
前 田  博 之
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
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 Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP3077505A priority Critical patent/JPH04310976A/en
Publication of JPH04310976A publication Critical patent/JPH04310976A/en
Pending legal-status Critical Current

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  • Developing For Electrophotography (AREA)
  • Control Or Security For Electrophotography (AREA)

Abstract

PURPOSE:To provide a stable image by adjusting a developing bias on a region corresponding to an original leading edge part, even in the case of a copying interval at the time of consecutive copying is short. CONSTITUTION:In an image forming device irradiating a photosensitive body uniformly electrified in advance with light after an original is exposed/scanned, to form a latent image, and forming an image by developing the latent image by means of a developing unit, a detecting means for detecting an exposure amount, that is, for detecting the exposure amount at a prescribed position before the original is scanned at the time of scanning and exposing, and an adjusting control means 400 adjusting the developing bias of the developing unit higher than a reference bias VB1 only for a prescribed time for developing an image top end part prescribed region when a detection value L obtained by the detecting means is lower than a reference value L2, are provided.

Description

【発明の詳細な説明】[Detailed description of the invention]

【0001】0001

【産業上の利用分野】本発明は画像形成装置に関し、特
に現像器のバイアス調整機能を有する画像形成装置に関
する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus having a developing device bias adjustment function.

【0002】0002

【従来の技術】複写機においては、原稿露光時の露光量
の変化が形成画像の品質に影響を及ぼす。このため従来
において、露光量の変化に対応して他の画像形成に作用
する条件(バイアス電圧等)を調整している。このよう
な装置として例えば、露光時の光量を検出し、検出値に
応じて現像器の現像バイアスを調整する装置(特開昭6
3−28957号公報)が提案されている。
2. Description of the Related Art In copying machines, changes in the amount of exposure during exposure of an original affect the quality of the formed image. For this reason, conventionally, other conditions that affect image formation (bias voltage, etc.) are adjusted in response to changes in exposure amount. An example of such a device is a device that detects the amount of light during exposure and adjusts the developing bias of the developing device according to the detected value (Japanese Patent Laid-Open No. 6
3-28957) has been proposed.

【0003】0003

【発明が解決しようとする課題】ところで、従来の複写
機では一搬的に露光用のランプにハロゲンランプが使用
されており、ランプの連続点灯を行なうとランプの寿命
が短くなるため、スキャナのリターン時はランプを消灯
するようにしている。しかし、複写機の処理高速化に伴
い、連続複写時における複写間隔も短くする必要があり
、複写間隔を短くして連続複写を行なうと、2回目以後
の走査時にスキャナが原稿走査開始点に到達しても露光
ランプが完全に立上がらないことがある。従来の装置(
特開昭63−28957号公報)においては、ランプ点
灯時の露光量の変化(小さな変化)に対応して現像器の
現像バイアスを調整するので、ランプ立上がり時の露光
量の変化(大きな変化)には対応できず、原稿先端部で
露光が不十分となり、形成される画像の一部が暗くなる
不具合があった。
[Problems to be Solved by the Invention] By the way, in conventional copying machines, halogen lamps are used as exposure lamps, and if the lamps are turned on continuously, the life of the lamps will be shortened. When returning, the lamp is turned off. However, as the processing speed of copying machines increases, it is necessary to shorten the copying interval during continuous copying.If the copying interval is shortened and continuous copying is performed, the scanner will reach the document scanning start point during the second and subsequent scans. However, the exposure lamp may not start up completely. Conventional equipment (
In Japanese Unexamined Patent Publication No. 63-28957), the developing bias of the developing device is adjusted in response to the change (small change) in the exposure amount when the lamp is turned on, so that the change (large change) in the exposure amount when the lamp is turned on is adjusted. This resulted in insufficient exposure at the leading edge of the document, resulting in a portion of the formed image becoming dark.

【0004】本発明は、連続複写時の複写間隔が短い場
合においても、原稿先端部に対応する領域での現像バイ
アスを調整することで、安定した画像を提供することを
目的とする。
An object of the present invention is to provide a stable image by adjusting the developing bias in the area corresponding to the leading edge of the document even when the copying interval during continuous copying is short.

【0005】[0005]

【課題を解決するための手段】本発明の画像形成装置は
、原稿を露光走査して得られた光を予め一様に帯電した
感光体(121)上に照射して潜像を形成し、該潜像を
現像器(124)で現像して画像を形成する画像形成装
置において、露光量を検出する検出手段(112a);
露光走査時に原稿走査前の所定位置での露光量を検出手
段(112a)で検出し、該検出値(L)が基準値(L
2)より小さいと画像先端部所定領域を現像する所定時
間だけ現像器(124)の現像バイアスを基準バイアス
(VB1)より高く調整する調整制御手段(400);
を備える。なお、カッコ内の記号は後述する実施例の対
応要素である。
[Means for Solving the Problems] The image forming apparatus of the present invention forms a latent image by irradiating light obtained by exposing and scanning a document onto a photoreceptor (121) uniformly charged in advance, and In an image forming apparatus that forms an image by developing the latent image with a developing device (124), a detection unit (112a) that detects an exposure amount;
During exposure scanning, the detection means (112a) detects the exposure amount at a predetermined position before scanning the original, and the detected value (L) is determined as the reference value (L).
2) adjustment control means (400) for adjusting the developing bias of the developing device (124) to be higher than the reference bias (VB1) for a predetermined time period for developing a predetermined region at the leading edge of the image;
Equipped with Note that the symbols in parentheses are corresponding elements in the embodiment described later.

【0006】[0006]

【作用】これによれば、調整制御手段(400)が、露
光走査時に原稿走査前の所定位置での露光量を検出手段
(112a)で検出し、該検出値(L)が基準値(L2
)より小さいと画像先端部所定領域を現像する所定時間
だけ現像器(124)の現像バイアスを基準バイアス(
VB1)より高く調整する。従って、露光開始時にラン
プが立上がらなかった場合やリピート時の時間の余裕不
足による原稿先端部での光量不足を原稿露光前に判断し
、現像バイアスを調整することでこれを補正するので、
原稿先端での光量不足による画像の暗さを解消すること
ができる。また、好ましい実施例においては、1枚目で
のランプ光量を基準光量としており、2枚目以後を基準
値と比較し、現像バイアスの出力を変えている為、常に
安定した画像が得られる。
[Operation] According to this, the adjustment control means (400) detects the amount of exposure at a predetermined position before scanning the document during exposure scanning with the detection means (112a), and the detected value (L) is set to the reference value (L2).
), the developing bias of the developing device (124) is set to the reference bias (
VB1) Adjust higher. Therefore, if the lamp does not start up at the start of exposure or if there is insufficient time to repeat the exposure, the insufficient amount of light at the leading edge of the document is determined before the document is exposed, and this is corrected by adjusting the developing bias.
It is possible to eliminate the darkness of the image due to insufficient light intensity at the leading edge of the document. Furthermore, in a preferred embodiment, the lamp light intensity for the first sheet is used as the reference light amount, and the second and subsequent sheets are compared with the reference value and the output of the developing bias is changed, so that a stable image can always be obtained.

【0007】さらに、本発明の好ましい実施例では、所
定位置に標準白色板(116)を備える。したがって検
出手段(112a)で光量検出を行なうときに、標準白
色板(116)の露光光により光量検出を行なうので検
出の精度が向上し、安定した画像が得られる。本発明の
他の目的および特徴は図面を参照した以下の実施例の説
明により明らかになろう。
Furthermore, a preferred embodiment of the present invention includes a standard white plate (116) at a predetermined location. Therefore, when the light amount is detected by the detection means (112a), the light amount is detected using the exposure light of the standard white plate (116), so the detection accuracy is improved and a stable image can be obtained. Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

【0008】[0008]

【実施例1】図1に本発明の一実例の複写機100の機
構概略を示す。複写機100は、原稿固定式の静電転写
型複写装置であり、光学系110,作像系120,給紙
系130および排紙系140等でなる。
Embodiment 1 FIG. 1 shows an outline of the mechanism of a copying machine 100 as an example of the present invention. The copying machine 100 is an electrostatic transfer type copying device with a fixed original, and includes an optical system 110, an image forming system 120, a paper feeding system 130, a paper ejection system 140, and the like.

【0009】光学系110は、コンタクトガラス111
およびその下方に配置された露光ランプ112,光量検
出センサ112a,第1ミラ−113A,第2ミラ−1
13B,第3ミラ−113C,第4ミラ−113D,第
5ミラ−113E,第6ミラ−113F,レンズ114
,防塵ガラス115ならびに標準白色板116等でなり
、作像系120は感光体ドラム121およびその周囲の
配設された帯電チャ−ジャ122,イレ−サ123,現
像器124,転写前チャ−ジャ126,分離チャ−ジャ
127,分離爪128,クリ−ニング前除電チャ−ジャ
(以下PCCという)129ならびにクリ−ナ12A、
および、感光体ドラム121の下流に配置された搬送ベ
ルト12Bならびに定着器12C等でなる。給紙系13
0は、手差給紙台131,給紙台131Aおよび給紙台
に備わる呼出しコロ132,給紙コロ133、ならびに
逆転コロ134、および、レジストロ−ラ135,ガイ
ドマイラ136ならびに各種ガイドおよび中間ロ−ラ等
でなる。なお、手差給紙台131は、呼出しコロ132
,給紙コロ133ならびに逆転コロ134を給紙台13
1Aと共用している。 排紙系140は、接離ロ−ラ142および排紙コロ14
1等でなる。
The optical system 110 includes a contact glass 111.
and an exposure lamp 112 arranged below, a light amount detection sensor 112a, a first mirror 113A, a second mirror 1
13B, third mirror 113C, fourth mirror 113D, fifth mirror 113E, sixth mirror 113F, lens 114
, a dustproof glass 115, a standard white plate 116, etc., and the image forming system 120 includes a photosensitive drum 121, a charger 122, an eraser 123, a developer 124, and a pre-transfer charger arranged around the photosensitive drum 121. 126, separation charger 127, separation claw 128, pre-cleaning static elimination charger (hereinafter referred to as PCC) 129, and cleaner 12A,
It also includes a conveyor belt 12B, a fixing device 12C, etc. arranged downstream of the photosensitive drum 121. Paper feed system 13
0 includes a manual paper feed tray 131, a paper feed tray 131A, a call roller 132, a paper feed roller 133, a reversing roller 134 provided on the paper feed tray, a registration roller 135, a guide mylar 136, and various guides and intermediate rollers. - Consists of la etc. Note that the manual paper feed tray 131 has a calling roller 132.
, the paper feed roller 133 and the reversing roller 134 are connected to the paper feed table 13.
It is shared with 1A. The paper ejection system 140 includes approach and separation rollers 142 and paper ejection rollers 14.
1st prize.

【0010】原稿がコンタクトガラス111上にセット
されスタ−ト指示があると、給紙クラッチがオンとなっ
てそのとき選択している給紙台の呼出しコロが記録紙を
給紙コロに送り出す。給紙コロは記録紙をレジストロ−
ラ135に向けて送り出す。この間、光学系110はコ
ンタクトガラス111上の原稿を走査し、露光ランプ1
12により照明した原稿の反射光を第1ミラ−113A
,第2ミラ−113B,第3ミラ−113C,レンズ1
14,第4ミラ−113D,第5ミラ−113E,第6
ミラ−113Fおよび防塵ガラス115を介して感光体
ドラム121の感光面に導びく。
When a document is set on the contact glass 111 and a start instruction is given, the paper feed clutch is turned on and the call roller of the paper feed table selected at that time feeds the recording paper to the paper feed roller. The paper feed roller registers the recording paper.
Send it towards La 135. During this time, the optical system 110 scans the original on the contact glass 111, and the exposure lamp 1
The reflected light from the original illuminated by 12 is reflected by the first mirror 113A.
, second mirror 113B, third mirror 113C, lens 1
14, 4th mirror-113D, 5th mirror-113E, 6th mirror
The light is guided to the photosensitive surface of the photosensitive drum 121 via the mirror 113F and the dustproof glass 115.

【0011】感光体ドラム121は、図示時計方向に回
転しており、その感光面は、光学系110より原稿反射
光の反射を受ける前に、帯電チャ−ジャ122により一
様に帯電され、イレ−サ123による除電で潜像領域が
形成されている。したがって、この潜像領域に原稿の反
射光が照射されるとその強弱に応じて光電導を生じ、静
電潜像が形成される。この静電潜像は現像器124によ
り現像され、原稿の濃度に応じてトナ−が付着したトナ
−像となる。このトナ−像は、レジストロ−ラ135か
ら繰り出される記録紙に転写されるが、転写を容易にす
るため、PTL125により転写前の除電がなされる。
The photosensitive drum 121 rotates clockwise in the drawing, and its photosensitive surface is uniformly charged by a charging charger 122 and erased before receiving the reflected light from the optical system 110. - A latent image area is formed by charge removal by the sensor 123. Therefore, when this latent image area is irradiated with light reflected from the original, photoconduction occurs depending on the strength of the light, and an electrostatic latent image is formed. This electrostatic latent image is developed by a developing device 124, and becomes a toner image with toner attached thereto according to the density of the document. This toner image is transferred onto the recording paper fed out from the registration roller 135, but in order to facilitate the transfer, the PTL 125 removes the charge before the transfer.

【0012】レジストロ−ラ135が繰り出した記録紙
は、ガイドマイラ136により感光体ドラム121の感
光面に密着され、転写チャ−ジャ126の直上でトナ−
像が転写される。この直後、記録紙は分離チャ−ジャ1
27により感光面から分離されるが、このとき分離が不
充分であると、分離爪128により強制的に分離される
。記録紙の分離後、感光体ドラム121の感光面はクリ
−ナ12Aにおいて残存トナ−が除去され、記録紙は搬
送ベルト12Bにより定着器12Cに送られる。定着器
12Cは、定着ロ−ラ12C1および加圧ロ−ラ12C
2を備え、トナ−像が転写された記録紙を圧力を加えな
がら加熱し(約185℃)、トナ−像を定着させる。ト
ナ−像が定着された記録紙は、再給紙系140に渡され
る。排紙系140は、記録紙を排紙コロ141に導びき
、記録紙は、排紙コロ141および接離ロ−ラ142に
よって装置外に排出される。
The recording paper fed out by the registration roller 135 is brought into close contact with the photosensitive surface of the photosensitive drum 121 by a guide mylar 136, and the toner is deposited directly above the transfer charger 126.
The image is transferred. Immediately after this, the recording paper is transferred to separation charger 1.
27, but if the separation is insufficient, the separation claw 128 forcibly separates the photosensitive material. After the recording paper is separated, residual toner is removed from the photosensitive surface of the photosensitive drum 121 by a cleaner 12A, and the recording paper is sent to a fixing device 12C by a conveyor belt 12B. The fixing device 12C includes a fixing roller 12C1 and a pressure roller 12C.
2, the recording paper onto which the toner image has been transferred is heated (approximately 185° C.) while applying pressure to fix the toner image. The recording paper with the toner image fixed thereon is delivered to a paper refeeding system 140. A paper discharge system 140 guides the recording paper to a paper discharge roller 141, and the recording paper is discharged from the apparatus by the paper discharge roller 141 and the contact/separation roller 142.

【0013】図2に、複写機100の電気制御系の概略
を示す。この電気制御系は、メイン制御部400を中心
に記憶部410,光学制御部420,AC制御部430
,および操作制御部440等でなる。
FIG. 2 schematically shows the electrical control system of the copying machine 100. This electrical control system includes a main control section 400, a storage section 410, an optical control section 420, and an AC control section 430.
, and an operation control unit 440.

【0014】メイン制御部400は、本体100の各部
に備わる各種センサ420(露光量検出センサ112a
を含む)を監視して各部のソレノイドやモ−タ等の負荷
や、現像器124のバイアス電圧等を制御する。光学制
御部420は、レンズ114を駆動するレンズモ−タや
光学走査を行なうためのスキャナモ−タを制御し、AC
制御部430は、露光ランプ112や定着器12Cのヒ
−タ,メインモ−タ,現像モ−タ,搬送モ−タおよび給
紙モ−タ等の交流負荷を制御する。操作制御部440は
、操作&表示ボ−ド150のキ−操作読取りおよび表示
制御を行なう。
The main control unit 400 includes various sensors 420 (exposure detection sensor 112a) provided in each part of the main body 100.
), and controls the loads of the solenoids and motors of various parts, the bias voltage of the developing device 124, etc. The optical control unit 420 controls the lens motor that drives the lens 114 and the scanner motor that performs optical scanning, and controls the AC
The control unit 430 controls AC loads such as the exposure lamp 112, the heater of the fixing device 12C, the main motor, the developing motor, the transport motor, and the paper feed motor. The operation control section 440 performs key operation reading and display control on the operation and display board 150.

【0015】ところで、複写機100では露光走査時に
、所定の位置(標準白色板116の走査位置)で、光量
検出センサ112aを用いて光量検出を行なう。このと
きに検出した光量に対する所定領域での現像バイアスの
設定値を、図3に示す。ランプ112(の点灯)が10
0%立上がった時の光量をL2とし、この時の現像器1
24の現像バイアスの設定をVB1とする。また、光量
がL2〜L1(L2>L1)であると現像バイアスの設
定をVB2とし、光量がL1以下であると現像バイアス
の設定をVB3とする。なお、VB1<VB2<VB3
である。
By the way, in the copying machine 100, during exposure scanning, the light amount is detected at a predetermined position (scanning position of the standard white plate 116) using the light amount detection sensor 112a. FIG. 3 shows the set value of the developing bias in a predetermined area with respect to the amount of light detected at this time. Lamp 112 (lit) is 10
The light intensity when it rises to 0% is L2, and the developing device 1 at this time
The developing bias setting of No. 24 is set to VB1. Further, when the light amount is between L2 and L1 (L2>L1), the developing bias is set to VB2, and when the light amount is less than L1, the developing bias is set to VB3. In addition, VB1<VB2<VB3
It is.

【0016】図4は、メイン制御部400のスキャナ制
御処理のフローチャートである。以下これについて説明
する。まず、初期化を行なう(ステップ1:以下カッコ
内ではステップと言う語は省略する)。この初期化では
、各レジスタ等をクリアし、スキャナを所定の位置(ホ
ーム位置)にセットする。次に、スタート指示があるま
で待機し(2)、スタート指示があると、複写回数を判
断するレジスタNを0にして(3)、ランプ112をオ
ンし、スキャナの走行を開始する(4)。スキャナが所
定の光量検出位置に到達すると(5)、このときの光量
をセンサ112aにより読取りLとする(6)。ここで
、Nの値が0であるかを判断し(7)、そうであると1
回目の複写と判断して読込んだ値Lを基準値L2とし、
現像器124の現像バイアスを所定値VB1に設定する
(8,9)。一方、Nの値が0でない場合は、連続複写
の2回目以後の複写と判断し、ステップ10〜14の処
理(バイアス調整処理)を行なう。この処理では読込ん
だ値Lが基準値L1以下であると現像器124の現像バ
イアスを所定値VB3に設定し(10,11)、Lが基
準値L2以上であると現像器124の現像バイアスを所
定値VB1に設定し(12,13)、LがL1〜L2の
範囲であると現像器124の現像バイアスを所定値VB
2に設定する(10,12,14)。なお、調整された
現像バイアスでの現像は所定時間だけ行なわれ、その後
は通常の現像バイアス(固定値)で現像が行なわれる。 その後、スキャナがリターン位置に到達すると(15)
、ランプ112をオフし、スキャナを逆方向に駆動する
(16)。スキャナがホーム位置に到達すると(17)
、設定回分の走査が終了していなければNの値を1とし
てステップ4に戻る(18,19)。定回分の走査が終
了した場合は、スキャナの走査を停止してステップ2に
戻り(20)、スタート指示の待機を行なう。
FIG. 4 is a flowchart of scanner control processing by the main control section 400. This will be explained below. First, initialization is performed (Step 1: The word "step" will be omitted below in parentheses). In this initialization, each register etc. are cleared and the scanner is set at a predetermined position (home position). Next, it waits until a start instruction is given (2), and when a start instruction is given, the register N for determining the number of copies is set to 0 (3), the lamp 112 is turned on, and the scanner starts running (4). . When the scanner reaches a predetermined light amount detection position (5), the light amount at this time is read by the sensor 112a and set as L (6). Here, it is determined whether the value of N is 0 (7), and if so, it is 1
The value L read after determining that it is the first copy is set as the reference value L2,
The developing bias of the developing device 124 is set to a predetermined value VB1 (8, 9). On the other hand, if the value of N is not 0, it is determined that the copying is the second or subsequent copying of continuous copying, and the processes of steps 10 to 14 (bias adjustment process) are performed. In this process, if the read value L is less than or equal to the reference value L1, the developing bias of the developing device 124 is set to a predetermined value VB3 (10, 11), and if L is greater than or equal to the reference value L2, the developing bias of the developing device 124 is set to a predetermined value VB3 (10, 11). is set to a predetermined value VB1 (12, 13), and when L is in the range of L1 to L2, the developing bias of the developing device 124 is set to a predetermined value VB1.
Set to 2 (10, 12, 14). Note that development is performed using the adjusted development bias for a predetermined period of time, and thereafter development is performed using a normal development bias (fixed value). After that, when the scanner reaches the return position (15)
, turn off lamp 112 and drive the scanner in the reverse direction (16). When the scanner reaches the home position (17)
, if the set number of scans has not been completed, the value of N is set to 1 and the process returns to step 4 (18, 19). When the regular number of scans is completed, the scanner stops scanning, returns to step 2 (20), and waits for a start instruction.

【0017】以上説明した動作の各々のタイミングおよ
び現像バイアス出力の変化を図5に示す。複写1枚目は
、時間の余裕があるため、露光ランプのONは、連続複
写時よりも速く行なうことができる。露光ランプをON
した後、スキャナ駆動が開始され、原稿先端部(L.E
.)の手前の標準白色板116の位置で光量を測定する
。1枚目は時間の余裕があるため、ランプが立ち上がっ
ているものとして、この値をランプ112の100%立
上がり時の光量L2とする。1枚目の現像バイアス値は
VB1となる。
FIG. 5 shows the timing of each of the operations described above and changes in the developing bias output. Since there is time to copy the first copy, the exposure lamp can be turned on more quickly than during continuous copying. Turn on the exposure lamp
After that, the scanner drive starts and the leading edge of the document (L.E.
.. ) The amount of light is measured at the position of the standard white plate 116 in front of. Since there is time for the first image, it is assumed that the lamp is turned on, and this value is set as the light amount L2 when the lamp 112 is turned on 100%. The developing bias value for the first sheet is VB1.

【0018】スキャナがリターンすると同時に露光ラン
プはOFFとなり、この後、スキャナが所定位置まで戻
ると2枚目の複写が始まる。2枚目以後は時間の余裕が
ないため、1枚目より遅いタイミングで露光ランプ11
2がオンとなる。スキャナ駆動が開始され、原稿先端部
(L.E.)の手前の標準白色板116の位置で光量を
測定する。この光量の値と1枚目の光量とを比較し、現
像バイアスの設定を行なう。原稿先端部(L.E.)か
らある一定の時間の間、上記設定されたバイアスの値を
現像器124に与える。なお、図中のT1は標準白色板
116の装着位置によって設定され、T2は原稿先端2
0mm程度の領域を現像する時間となるように設定され
る。
The exposure lamp is turned off at the same time as the scanner returns, and then, when the scanner returns to a predetermined position, copying of the second sheet begins. Since there is not enough time for the second and subsequent shots, I turned on the exposure lamp 11 at a later timing than for the first shot.
2 is turned on. Scanner drive is started, and the amount of light is measured at the position of the standard white plate 116 in front of the leading edge (LE) of the document. The value of this light amount is compared with the light amount of the first sheet, and the developing bias is set. The bias value set above is applied to the developing device 124 for a certain period of time from the leading edge (LE) of the document. Note that T1 in the figure is set depending on the mounting position of the standard white plate 116, and T2 is set depending on the mounting position of the standard white plate 116.
The time is set to develop an area of about 0 mm.

【0019】[0019]

【発明の効果】以上のように本発明によれば、調整制御
手段(400)が、露光走査時に原稿走査前の所定位置
での露光量を検出手段(112a)で検出し、該検出値
(L)が基準値(L2)より小さいと画像先端部所定領
域を現像する所定時間だけ現像器(124)の現像バイ
アスを基準バイアス(VB1)より高く調整する。従っ
て、露光開始時にランプが立上がらなかった場合やリピ
ート時の時間の余裕不足による原稿先端部での光量不足
を原稿露光前に判断し、現像バイアスを調整することで
これを補正するので、原稿先端での光量不足による画像
の暗さを解消することができる。
As described above, according to the present invention, the adjustment control means (400) uses the detection means (112a) to detect the exposure amount at a predetermined position before scanning the document during exposure scanning, and calculates the detected value ( If L) is smaller than the reference value (L2), the developing bias of the developing device (124) is adjusted to be higher than the reference bias (VB1) for a predetermined period of time to develop a predetermined region at the leading edge of the image. Therefore, the lack of light at the leading edge of the document due to the lamp not starting up at the start of exposure or lack of time during repeat is determined before the document is exposed, and this is corrected by adjusting the developing bias. It is possible to eliminate the darkness of the image due to insufficient light intensity at the tip.

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

【図1】  本発明の一例である複写機の構成概略を示
す側面図である。
FIG. 1 is a side view showing a schematic configuration of a copying machine that is an example of the present invention.

【図2】  図1に示す複写機100の制御系の概略を
示すブロック図である。
2 is a block diagram schematically showing a control system of the copying machine 100 shown in FIG. 1. FIG.

【図3】  露光量検出センサ112aで検出した光量
に対する、所定領域での現像バイアスの設定値を示すグ
ラフである。
FIG. 3 is a graph showing the setting value of the developing bias in a predetermined area with respect to the amount of light detected by the exposure amount detection sensor 112a.

【図4】  メイン制御部400の制御動作を示すフロ
−チャ−トである。
FIG. 4 is a flowchart showing the control operation of the main control section 400.

【図5】  光量読取りタイミングおよび現像バイアス
出力の変化を示すタイムチャートである。
FIG. 5 is a time chart showing changes in light amount reading timing and developing bias output.

【符号の説明】[Explanation of symbols]

100:複写機                  
      110:光学系112a:露光量検出セン
サ(検出手段)   116:標準白色板(標準白色板
) 120:作像系                  
      121:感光体(感光体)
100: Copy machine
110: Optical system 112a: Exposure detection sensor (detection means) 116: Standard white plate (standard white plate) 120: Image forming system
121: Photoreceptor (photoreceptor)

Claims (3)

【特許請求の範囲】[Claims] 【請求項1】原稿を露光走査して得られた光を予め一様
に帯電した感光体上に照射して潜像を形成し、該潜像を
現像器で現像して画像を形成する画像形成装置において
、露光量を検出する検出手段;露光走査時に原稿走査前
の所定位置での露光量を検出手段で検出し、該検出値が
基準値より小さいと画像先端部所定領域を現像する所定
時間だけ現像器の現像バイアスを基準バイアスより高く
調整する調整制御手段;を備える画像形成装置。
[Claim 1] An image in which a latent image is formed by irradiating light obtained by exposing and scanning a document onto a photoreceptor that has been uniformly charged in advance, and the latent image is developed with a developing device to form an image. In the forming apparatus, a detection means for detecting the exposure amount; during exposure scanning, the detection means detects the exposure amount at a predetermined position before scanning the document, and if the detected value is smaller than a reference value, a predetermined detection means is used to develop a predetermined area at the leading edge of the image. An image forming apparatus comprising: an adjustment control means for adjusting a developing bias of a developing device to be higher than a reference bias by an amount of time.
【請求項2】前記所定位置に標準白色板を備える、前記
請求項1記載の画像形成装置。
2. The image forming apparatus according to claim 1, further comprising a standard white plate at the predetermined position.
【請求項3】原稿を露光走査して得られた光を予め一様
に帯電した感光体上に照射して潜像を形成し、該潜像を
現像器で現像して画像を形成する画像形成方法において
、露光走査時において原稿走査前の所定位置での露光量
を検出し、該検出値が基準値より小さいと画像先端部所
定領域を現像する所定時間だけ現像器の現像バイアスを
基準バイアスより高く調整して画像を形成する画像形成
方法。
3. An image in which a latent image is formed by irradiating light obtained by exposing and scanning a document onto a photoreceptor that has been uniformly charged in advance, and the latent image is developed with a developing device to form an image. In the forming method, during exposure scanning, the exposure amount at a predetermined position before scanning the document is detected, and if the detected value is smaller than a reference value, the developing bias of the developing device is changed to the reference bias for a predetermined time to develop a predetermined area at the leading edge of the image. An image forming method that forms images with higher adjustment.
JP3077505A 1991-04-10 1991-04-10 Image forming device Pending JPH04310976A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3077505A JPH04310976A (en) 1991-04-10 1991-04-10 Image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3077505A JPH04310976A (en) 1991-04-10 1991-04-10 Image forming device

Publications (1)

Publication Number Publication Date
JPH04310976A true JPH04310976A (en) 1992-11-02

Family

ID=13635826

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3077505A Pending JPH04310976A (en) 1991-04-10 1991-04-10 Image forming device

Country Status (1)

Country Link
JP (1) JPH04310976A (en)

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