JP2003226041A - Laser light amount controlling method for electrophotography apparatus - Google Patents

Laser light amount controlling method for electrophotography apparatus

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Publication number
JP2003226041A
JP2003226041A JP2002025562A JP2002025562A JP2003226041A JP 2003226041 A JP2003226041 A JP 2003226041A JP 2002025562 A JP2002025562 A JP 2002025562A JP 2002025562 A JP2002025562 A JP 2002025562A JP 2003226041 A JP2003226041 A JP 2003226041A
Authority
JP
Japan
Prior art keywords
light
light source
light amount
amount
δvpd
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
JP2002025562A
Other languages
Japanese (ja)
Inventor
Toshihide Inaba
俊秀 稲葉
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 Printing Systems Ltd
Original Assignee
Hitachi Printing Solutions Inc
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 Hitachi Printing Solutions Inc filed Critical Hitachi Printing Solutions Inc
Priority to JP2002025562A priority Critical patent/JP2003226041A/en
Publication of JP2003226041A publication Critical patent/JP2003226041A/en
Pending legal-status Critical Current

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  • Exposure Or Original Feeding In Electrophotography (AREA)
  • Facsimile Heads (AREA)
  • Facsimile Scanning Arrangements (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controlling system capable of restraining printing irregularity derived from the light amount difference by providing the correlation to the light amounts of light sources arranged adjacently in the front and rear direction out of a plurality of light sources by a laser light amount controlling part of an electrophotography apparatus. <P>SOLUTION: The electrophotography apparatus comprises a means for adding the light amount change amount ΔVpd(n) of the nth (n: natural number) light source (n) to the reference voltage Vref(n+1) of the n+1th light source (n+1) out of m sets of light sources arranged in the order of a light source 1, a light source 2,..., a light source m in a light amount controlling part for a plurality of light sources, and a means for adding the light amount change amount ΔVpd(m) of the mth light source (m) to the reference voltage Vref(1) of the 1st light source (1) for restraining the light amount difference between the light sources arranged adjacently in the front and rear direction. <P>COPYRIGHT: (C)2003,JPO

Description

【発明の詳細な説明】 【0001】 【発明の属する技術分野】本発明は、電子写真装置のレ
ーザ光量制御方法に関するものである。 【0002】 【従来の技術】従来の電子写真装置のレーザ光量制御方
法について図1を用いて説明する。図1は電子写真装置
のレーザ光量制御部を示すブロック図である。図1にお
いて、レーザダイオード5は電子写真装置の光源で、レ
ーザダイオード5が出力するレーザビームのオン/オフ
信号が感光ドラムの表面に静電潜像を形成する。 【0003】図3に示すように、m個の光源が、光源
(1)、光源(2)、・・・、光源(m)の順で配列し
ている場合において、n番目(n:自然数)の光源
(n)であるレーザダイオード5の光量は、レーザダイ
オード5と直列に配置する定電流回路3の電流iLD
(n)により制御している。レーザダイオード5と対向
する位置に配置した光量検出センサは、フォトダイオー
ド6により構成され、レーザダイオード5の光量に応じ
た電流iPD(n)を出力し、光量検出回路4はiPD
(n)を電流−電圧変換して光量に応じた電圧Vpd
(n)を出力する。比較回路2はレーザダイオード5が
所定の光量となる既知の値に調整された基準電圧Vre
fと、Vpd(n)の電圧を比較して、Vpd(n)=
Vref−α・iLD(n)=一定(Vref:一定、
α:回路定数)の関係を成立させるように、光量検出回
路4の出力変化量ΔVpd(n)が、ΔVpd>0の場
合はiLDを減少させ、ΔVpd<0の場合はiLDを
増加させる動作を行う。以上説明したように、従来の電
子写真装置においては、光量検出回路4の出力Vpdを
一定とするフィードバック制御を用いて、レーザダイオ
ード5の光量が一定となるように制御している。また、
光源が複数ある場合についても、同じ基準電圧Vref
を用いて、光量が一定となるようにフィードバック制御
している。 【0004】 【発明が解決しようとする課題】以上説明したように、
従来の電子写真装置のレーザ光量制御部においては、複
数ある光源のそれぞれが一定の光量となるようにフィー
ドバック制御している。しかし、複数ある光源の光量は
それぞれ独立に制御され、どれか1つの光量が低下、又
は増加した場合に残りの光源は所定の光量で発光し続け
るため、複数の光源に光量差が発生してしまう。 【0005】本発明は、前後に配列した光源の光量に相
関をもたせ、前の光源の光量変化に追従して次の光源の
光量制御を行い、光量差による印刷むらを抑える制御方
式を提供することを目的とする。 【0006】 【課題を解決するための手段】上記目的を達成するため
に、本発明の電子写真装置のレーザ光量制御方法におい
ては、光源1、光源2、・・・、光源mの順で配列した
m個の光源のうち、n番目(n:自然数)にある光源
(n)の光量変化量ΔVpd(n)をn+1番目にある
光源(n+1)の基準電圧Vref(n+1)に加算す
るとともに、m番目にある光源(m)の光量変化量ΔV
pd(m)を1番目にある光源(1)の基準電圧Vre
f(1)に加算することを特徴とする。 【0007】 【発明の実施の形態】以下、本発明の一実施例を説明す
る。 【0008】従来の電子写真装置のレーザ光量制御につ
いて図2を用いて説明する。図2は電子写真装置のレー
ザ光量制御部を示すブロック図である。図2において、
レーザダイオード5は電子写真装置の光源で、レーザダ
イオード5が出力するレーザビームのオン/オフ信号が
感光ドラムの表面に静電潜像を形成する。レーザダイオ
ード5の光量は、レーザダイオード5と直列に配置する
定電流回路3の電流iLD(n)により制御している。 【0009】前述したように、前後に配列した光源の相
関について、図3に示すように、光源(1)、光源
(2)、・・・、光源(m)の順で配列したm個の光源
のうち、n番目とn+1番目の光量制御を例に説明す
る。n番目(n:自然数)の光源(n)であるレーザダ
イオード5の光量検出センサはフォトダイオード6によ
り構成され、レーザダイオード5の光量に応じた電流i
PD(n)を出力し、光量検出回路4はiPD(n)を
電流−電圧変換して光量に応じた電圧Vpd(n)を出
力する。A/Dコンバータ13は、例えば、レーザダイ
オードの光量調整が終了した後に、光量検出回路4が出
力する光量の初期値VpdF(n)を検出する。光量の
初期値VpdF(n)はメモリ15に格納され、パワー
オン中にD/Aコンバータ14は光量の初期値VpdF
(n)を出力し続ける。 光量変化検出回路18は、D
/Aコンバータが出力するVpdF(n)と現在の光量
検出回路の出力Vpd(n)を比較して、光源(n)の
光量変化量ΔVpd(n)(=VpdF(n)−Vpd
(n))を出力する。 【0010】次に、n+1番目の光源(n+1)につい
ても同様に、光源(n+1)であるレーザダイオード1
0の光量検出センサはフォトダイオード11により構成
され、レーザダイオード10の光量に応じた電流iPD
(n+1)を出力し、光量検出回路9はiPD(n+
1)を電流−電圧変換して光量に応じた電圧Vpd(n
+1)を出力する。A/Dコンバータ13は、例えば、
レーザダイオードの光量調整が終了した後に、光量検出
回路9が出力する光量の初期値VpdF(n+1)を検
出する。光量の初期値VpdF(n+1)はメモリ15
に格納され、パワーオン中にD/Aコンバータ14は光
量の初期値VpdF(n+1)を出力し続ける。光量変
化検出回路17は、D/Aコンバータが出力するVpd
F(n+1)と現在の光量検出回路の出力Vpd(n+
1)を比較して、光源(n+1)の光量変化量ΔVpd
(n+1)(=VpdF(n+1)−Vpd(n+
1))を出力する。 【0011】ここで、光源(n+1)の基準電圧補正回
路12は、光源(n+1)が所定の光量となる既知の値
に調整された基準電圧Vref(n+1)に光源(n)
の光量変化量ΔVpd(n)を加算して、基準電圧を補
正する。比較回路7は補正した基準電圧Vref(n+
1)+ΔVpd(n)と光量検出回路9の出力電圧Vp
d(n+1)を比較して、Vpd(n+1)=Vref
(n+1)+ΔVpd(n)−α・iLD(α:回路定
数)の関係を成立させるように、光量検出回路9の出力
変化量ΔVpd(n)が、ΔVpd(n+1)>0の場
合はiLD(n+1)を減少させ、ΔVpd(n+1)
<0の場合はiLD(n+1)を増加させる動作を行
う。よって、光源(n)の光量変化量に追従させて光源
(n+1)の光量制御が可能である。さらに、1番目の
光源(1)については、m番目にある光源(m)の光量
変化量ΔVpd(m)を1番目の光源(1)の基準電圧
Vref(1)に加算して、光源(m)の光量変化と追
従させて光源(1)の光量制御を行う。 【0012】 【発明の効果】以上説明したように本発明によれば、電
子写真装置の複数ある光源うち、前後して配列した光源
の光量に相関を持たせ、前の光源の光量変化に追従させ
て、次の光源の光量を制御することで、光量差による印
刷むらを低減することが可能である。
Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a laser light amount control method for an electrophotographic apparatus. 2. Description of the Related Art A conventional laser light amount control method for an electrophotographic apparatus will be described with reference to FIG. FIG. 1 is a block diagram showing a laser light amount control unit of the electrophotographic apparatus. In FIG. 1, a laser diode 5 is a light source of an electrophotographic apparatus, and an on / off signal of a laser beam output from the laser diode 5 forms an electrostatic latent image on the surface of a photosensitive drum. As shown in FIG. 3, when m light sources are arranged in the order of light source (1), light source (2),..., Light source (m), the n-th light source (n: natural number) The light amount of the laser diode 5 which is the light source (n) is determined by the current iLD of the constant current circuit 3 arranged in series with the laser diode 5.
(N). The light amount detection sensor arranged at a position facing the laser diode 5 is constituted by a photodiode 6, outputs a current iPD (n) corresponding to the light amount of the laser diode 5, and the light amount detection circuit 4
(N) is subjected to current-voltage conversion to obtain a voltage Vpd corresponding to the amount of light.
(N) is output. The comparison circuit 2 outputs a reference voltage Vre adjusted to a known value at which the laser diode 5 has a predetermined light amount.
f is compared with the voltage of Vpd (n), and Vpd (n) =
Vref−α · iLD (n) = constant (Vref: constant,
α: a circuit constant), the output change amount ΔVpd (n) of the light amount detection circuit 4 decreases iLD when ΔVpd> 0, and increases iLD when ΔVpd <0. Do. As described above, in the conventional electrophotographic apparatus, the feedback control for keeping the output Vpd of the light quantity detection circuit 4 constant is used to control the light quantity of the laser diode 5 to be constant. Also,
Even when there are a plurality of light sources, the same reference voltage Vref
Is used to perform feedback control so that the light amount becomes constant. [0004] As described above,
In a laser light amount control unit of a conventional electrophotographic apparatus, feedback control is performed so that each of a plurality of light sources has a constant light amount. However, the light amounts of a plurality of light sources are independently controlled, and when one of the light amounts decreases or increases, the remaining light sources continue to emit light at a predetermined light amount. I will. The present invention provides a control method for correlating the light amounts of the light sources arranged in front and back, controlling the light amount of the next light source following changes in the light amount of the previous light source, and suppressing printing unevenness due to the light amount difference. The purpose is to: In order to achieve the above object, in the method for controlling the amount of laser light in an electrophotographic apparatus according to the present invention, a light source 1, a light source 2,... Among the m light sources, the light amount change amount ΔVpd (n) of the nth light source (n) (n: natural number) is added to the reference voltage Vref (n + 1) of the (n + 1) th light source (n + 1), Light amount change amount ΔV of the m-th light source (m)
pd (m) is the reference voltage Vre of the first light source (1).
It is characterized by adding to f (1). An embodiment of the present invention will be described below. [0008] Laser light quantity control of a conventional electrophotographic apparatus will be described with reference to FIG. FIG. 2 is a block diagram illustrating a laser light amount control unit of the electrophotographic apparatus. In FIG.
The laser diode 5 is a light source of an electrophotographic apparatus, and an on / off signal of a laser beam output from the laser diode 5 forms an electrostatic latent image on the surface of the photosensitive drum. The light quantity of the laser diode 5 is controlled by the current iLD (n) of the constant current circuit 3 arranged in series with the laser diode 5. As described above, regarding the correlation between the light sources arranged in front and behind, as shown in FIG. 3, m light sources (1), light sources (2),... The light quantity control of the nth and (n + 1) th light sources will be described as an example. The light amount detection sensor of the laser diode 5 which is the n-th (n: natural number) light source (n) is constituted by the photodiode 6, and the current i corresponding to the light amount of the laser diode 5
PD (n) is output, and the light quantity detection circuit 4 performs current-voltage conversion on iPD (n) and outputs a voltage Vpd (n) corresponding to the light quantity. The A / D converter 13 detects, for example, the initial value VpdF (n) of the light amount output by the light amount detection circuit 4 after the adjustment of the light amount of the laser diode ends. The initial value VpdF (n) of the light amount is stored in the memory 15, and during power-on, the D / A converter 14 sets the initial value VpdF of the light amount.
(N) is continuously output. The light amount change detection circuit 18
By comparing VpdF (n) output from the A / A converter with the current output Vpd (n) of the light amount detection circuit, the light amount change amount ΔVpd (n) of the light source (n) (= VpdF (n) −Vpd)
(N)) is output. Next, the laser diode 1 which is the light source (n + 1) is similarly used for the (n + 1) th light source (n + 1).
The light amount detection sensor of 0 is constituted by a photodiode 11 and outputs a current iPD corresponding to the light amount of the laser diode 10.
(N + 1), and the light amount detection circuit 9 outputs the iPD (n +
1) is subjected to current-voltage conversion and a voltage Vpd (n
+1) is output. The A / D converter 13 is, for example,
After the adjustment of the light amount of the laser diode is completed, the light amount detection circuit 9 detects the initial value VpdF (n + 1) of the light amount. The initial value VpdF (n + 1) of the light amount is stored in the memory 15.
During power-on, the D / A converter 14 keeps outputting the initial value VpdF (n + 1) of the light amount. The light amount change detection circuit 17 detects the Vpd output from the D / A converter.
F (n + 1) and the current output Vpd (n +
1) to compare the light amount change amount ΔVpd of the light source (n + 1).
(N + 1) (= VpdF (n + 1) -Vpd (n +
1)) is output. Here, the reference voltage correction circuit 12 of the light source (n + 1) applies the light source (n) to the reference voltage Vref (n + 1) adjusted to a known value at which the light source (n + 1) has a predetermined light amount.
The reference voltage is corrected by adding the light amount change amount ΔVpd (n). The comparison circuit 7 outputs the corrected reference voltage Vref (n +
1) + ΔVpd (n) and output voltage Vp of light quantity detection circuit 9
By comparing d (n + 1), Vpd (n + 1) = Vref
If the output change amount ΔVpd (n) of the light amount detection circuit 9 is ΔVpd (n + 1)> 0, iLD ( n + 1), and ΔVpd (n + 1)
If <0, an operation to increase iLD (n + 1) is performed. Therefore, the light amount of the light source (n + 1) can be controlled by following the light amount change amount of the light source (n). Further, for the first light source (1), the light amount change amount ΔVpd (m) of the m-th light source (m) is added to the reference voltage Vref (1) of the first light source (1), and the light source ( The light amount of the light source (1) is controlled by following the light amount change of m). As described above, according to the present invention, among the plurality of light sources of the electrophotographic apparatus, the light amounts of the light sources arranged one after another are correlated to follow the light amount change of the previous light source. By controlling the light amount of the next light source, it is possible to reduce printing unevenness due to the light amount difference.

【図面の簡単な説明】 【図1】従来の電子写真装置におけるレーザ光量制御部
を示すブロック図。 【図2】本発明の電子写真装置におけるレーザ光量制御
部を示すブロック図。 【図3】本発明の電子写真装置における光源とレーザ光
の位置関係を示す概略図。 【符号の説明】 1:従来技術における光源の基準電圧生成回路 2:n番目の光源の比較回路 3:n番目の光源の定電流回路 4:n番目の光源の光量検出回路 5:n番目の光源のレーザダイオード 6:n番目の光源のフォトダイオード 7:n+1番目の光源の比較回路 8:n+1番目の光源の定電流回路 9:n+1番目の光源の光量検出回路 10:n+1番目の光源のレーザダイオード 11:n+1番目の光源のフォトダイオード 12:n+1番目の光源の基準電圧補正回路 13:A/Dコンバータ 14:D/Aコンバータ 15:メモリ 16:n+1番目の光源の基準電圧生成回路 17:n+1番目の光源の光量変化検出回路 18:n番目の光源の光量変化検出回路 19:m個の光源 20:感光ドラム 21:回転多面鏡 22:転写器 23:用紙
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a laser light amount control unit in a conventional electrophotographic apparatus. FIG. 2 is a block diagram showing a laser light amount control unit in the electrophotographic apparatus of the present invention. FIG. 3 is a schematic diagram showing a positional relationship between a light source and a laser beam in the electrophotographic apparatus of the present invention. DESCRIPTION OF THE SYMBOLS 1: Reference voltage generation circuit of light source in prior art 2: Comparison circuit of nth light source 3: Constant current circuit of nth light source 4: Light quantity detection circuit of nth light source 5: nth light source Light source laser diode 6: n-th light source photodiode 7: n + 1-th light source comparison circuit 8: n + 1-th light source constant current circuit 9: n + 1-th light source light quantity detection circuit 10: n + 1-th light source laser Diode 11: photodiode of the (n + 1) th light source 12: reference voltage correction circuit 13 of the (n + 1) th light source 13: A / D converter 14: D / A converter 15: memory 16: reference voltage generation circuit 17 of the (n + 1) th light source: n + 1 Light amount change detection circuit 18 of the nth light source: Light amount change detection circuit 19 of the nth light source 19: m light sources 20: photosensitive drum 21: rotating polygon mirror 22: transfer unit 23: paper

Claims (1)

【特許請求の範囲】 【請求項1】複数の光源と、それぞれの光源の光量検出
センサと、基準電圧生成回路を有し、各光源の光量検出
センサ出力Vpd、基準電圧Vref、駆動電流iLD
がVpd=Vref−α・iLD=一定(Vref:一
定、α:回路定数)の関係で、光量検出センサの出力変
化量ΔVpdがΔVpd>0の場合はiLDを減少さ
せ、ΔVpd<0の場合はiLDを増加させて、光量検
出センサ出力Vpdを一定とするフィードバック制御を
用いた電子写真装置において、光源(1)、光源
(2)、・・・、光源(m)の順で配列したm個の光源
のうち、n番目(n:自然数)にある光源(n)の光量
検出センサ出力変化量ΔVpd(n)と、n+1番目に
ある光源(n+1)の光量検出センサ出力Vpd(n+
1)、基準電圧Vref(n+1)、駆動電流iLD
(n+1)が、Vpd(n+1)={Vref(n+
1)+ΔVpd(n)}−α・iLD(n+1)の関係
で、m番目にある光源(m)の光量検出センサ出力変化
量ΔVpd(m)と、1番目にある光源(1)の光量検
出センサ出力Vpd(1)、基準電圧Vref(1)、
駆動電流iLD(1)が、Vpd(1)={Vref
(1)+ΔVpd(m)}−α・iLD(1)の関係で
あることを特徴とする、電子写真装置のレーザ光量制御
方法。
Claims: 1. A light source detecting device comprising a plurality of light sources, a light amount detecting sensor of each light source, and a reference voltage generating circuit, wherein a light amount detecting sensor output Vpd, a reference voltage Vref, and a driving current iLD of each light source are provided.
Is a relation of Vpd = Vref−α · iLD = constant (Vref: constant, α: circuit constant), iLD is reduced when the output change amount ΔVpd of the light amount detection sensor is ΔVpd> 0, and when ΔVpd <0, In an electrophotographic apparatus using feedback control in which the iLD is increased and the light output detection sensor output Vpd is constant, m light sources (1), light sources (2),..., light sources (m) are arranged in this order. Of the light sources (n) (n: a natural number) of the light source (n), the light amount detection sensor output change amount ΔVpd (n) and the light amount detection sensor output Vpd (n + n) of the (n + 1) th light source (n + 1)
1), reference voltage Vref (n + 1), drive current iLD
(N + 1) is Vpd (n + 1) = {Vref (n +
1) In the relationship of + ΔVpd (n)} − α · iLD (n + 1), the light amount detection sensor output change amount ΔVpd (m) of the m-th light source (m) and the light amount detection of the first light source (1) Sensor output Vpd (1), reference voltage Vref (1),
When the drive current iLD (1) is Vpd (1) = {Vref
(1) A method for controlling the amount of laser light in an electrophotographic apparatus, characterized by a relationship of + ΔVpd (m)} − α · iLD (1).
JP2002025562A 2002-02-01 2002-02-01 Laser light amount controlling method for electrophotography apparatus Pending JP2003226041A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8233016B2 (en) 2005-10-17 2012-07-31 Konica Minolta Business Technologies, Inc. Image forming apparatus, and exposure control method therefor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8233016B2 (en) 2005-10-17 2012-07-31 Konica Minolta Business Technologies, Inc. Image forming apparatus, and exposure control method therefor

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