JPH0555871B2 - - Google Patents
Info
- Publication number
- JPH0555871B2 JPH0555871B2 JP58134841A JP13484183A JPH0555871B2 JP H0555871 B2 JPH0555871 B2 JP H0555871B2 JP 58134841 A JP58134841 A JP 58134841A JP 13484183 A JP13484183 A JP 13484183A JP H0555871 B2 JPH0555871 B2 JP H0555871B2
- Authority
- JP
- Japan
- Prior art keywords
- document
- scanning
- developing
- image
- density
- 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.)
- Expired - Lifetime
Links
- 238000001514 detection method Methods 0.000 claims description 6
- 239000011521 glass Substances 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 108091008695 photoreceptors Proteins 0.000 claims description 2
- 230000004044 response Effects 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 8
- 230000003287 optical effect Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000006870 function Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000003708 edge detection Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 238000003079 width control Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/50—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control
- G03G15/5025—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control by measuring the original characteristics, e.g. contrast, density
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Developing For Electrophotography (AREA)
- Control Of Exposure In Printing And Copying (AREA)
- Control Or Security For Electrophotography (AREA)
- Facsimile Scanning Arrangements (AREA)
- Facsimile Image Signal Circuits (AREA)
Description
【発明の詳細な説明】
本発明は複写機等の画像形成装置に関する。従
来複写機の転写画像濃度を適量に調整するには第
１図に示すような操作部内のボリユームVR１等
を調整する等して第２図に示す原稿露光ランプ
LA１の点灯電圧を変化させ適正画像を得るとい
うのが一般的であつた。しかしながら、従来のこ
のような方式では適正画像を得るまでに数枚の転
写紙を無駄にするというケースが多く転写紙の使
用量が必要枚数以上に増大するという欠点があつ
た。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus such as a copying machine. Conventionally, to adjust the transferred image density of a copying machine to an appropriate amount, adjust the volume VR1 etc. in the operation section as shown in Fig. 1, and use the document exposure lamp shown in Fig. 2.
It was common practice to obtain an appropriate image by changing the lighting voltage of LA1. However, in this conventional method, there are many cases in which several sheets of transfer paper are wasted before obtaining a proper image, and there is a drawback that the amount of transfer paper used increases beyond the necessary number.
本発明は従来のこの種の欠点を除去するために
なされたもので原稿露光時原稿面からの反射光を
光検知素子により検知し又は感光ドラムの電位を
検知し、その出力レベルに応じて原稿濃度を判断
して適量な現像バイアスの制御を行い、適正濃度
の画像を得ようとするものであり、詳細には、原
稿を載置する原稿台ガラス、前記原稿台ガラス上
の原稿を露光走査する走査手段、感光体上に原稿
画像に対応する静電潜像を形成する潜像形成手
段、前記静電潜像を前記走査手段の走査タイミン
グに対して所定時間遅れで現像する現像手段、前
記走査手段が原稿の先端走査位置にあることを検
出する位置検出手段、前記位置検出手段の検出出
力に応答して計時を開始し、前記現像手段が現像
動作を開始するまで時間を計時し、記憶する第１
計時手段、前記第１計時手段が記憶している時間
を計時する度に出力信号を発生する第２計時手
段、前記走査手段の像形成のための走査中に、前
記第２計時手段の前記出力信号に従つて、原稿を
露光走査方向において数個の領域に分割し、各分
割領域内で所定周期で複数回サンプリングして各
分割領域内の原稿濃度をそれぞれ検出する濃度検
出手段、前記濃度検出手段の各サンプル値をデジ
タル値に変換するデジタル変換手段、前記分割領
域の夫々について前記デジタル変換手段の出力を
加算して、前記分割領域における原稿濃度の平均
値を求める演算手段、前記演算手段の演算結果に
従つて、前記分割領域に対応する領域部分の原稿
画像を前記現像手段が現像する際の現像バイアス
を制御する制御手段を有し、前記制御手段は前記
各分割領域の現像バイアスを、前記第２計時手段
の前記出力信号に応じたタイミングで切換制御す
ると共に、前記演算手段及び前記制御手段は夫々
演算及び現像バイアスの制御を繰返すことを特徴
とする画像形成装置の提供を目的としている。 The present invention has been made in order to eliminate this type of conventional drawback, and when an original is exposed, the reflected light from the original surface is detected by a photodetector element, or the potential of a photosensitive drum is detected, and the original is detected according to the output level. The purpose is to determine the density and control the appropriate amount of developing bias to obtain an image with an appropriate density.In detail, it involves the use of an original platen glass on which the original is placed, and an exposure scan of the original on the original platen glass. a scanning means for forming an electrostatic latent image corresponding to a document image on a photoreceptor; a developing means for developing the electrostatic latent image with a predetermined time delay with respect to the scanning timing of the scanning means; a position detecting means for detecting that the scanning means is at the leading edge scanning position of the document; a position detecting means that starts measuring time in response to a detection output of the position detecting means, measures and stores time until the developing means starts a developing operation; First thing to do
a timer; a second timer that generates an output signal each time the first timer measures a time stored in the memory; a second timer that generates an output signal each time the first timer measures a time stored in the memory; a density detection means for dividing a document into several regions in the exposure scanning direction in accordance with a signal, sampling each divided region multiple times at a predetermined period, and detecting the density of the document in each divided region; digital conversion means for converting each sample value of the means into a digital value; a calculation means for adding the outputs of the digital conversion means for each of the divided areas to obtain an average value of document density in the divided areas; The control means controls the developing bias when the developing means develops the document image in the area corresponding to the divided area according to the calculation result, and the control means controls the developing bias of each divided area. It is an object of the present invention to provide an image forming apparatus characterized in that switching control is performed at a timing according to the output signal of the second timer, and the calculation means and the control means repeat calculation and control of the developing bias, respectively. .
斯かる構成により、プリスキヤンを必要とせず
に、適正画像濃度が得られ、また、同一の計時手
段の出力により領域の設定及び現像バイアスの切
換を行うので、正確なタイミングで各領域の濃度
制御が可能となる。 With this configuration, appropriate image density can be obtained without the need for pre-scanning, and since the area setting and development bias switching are performed using the output of the same timing means, the density control of each area can be performed at accurate timing. It becomes possible.
第３図に本発明の一実施例を示す。インミラー
ランズIMの手前に光センサDH、本実施例では
フオトダイオードを設置し原稿ガラスPCからの
反射光の強度を検知する。尚、Ｄは感光ドラム、
Ｌは原稿露光ランプである。第４図にその検知回
路を示す。PHのフオトダイオード１による検出
信号をオペアンプ２で増巾し、オペアンプ３でゲ
イン調整してADコンバータ内蔵のマイクロコン
ピユータ７のAD1入力へ入力する。マイクロコ
ンピユータ７はAD1の入力レベルとボリユーム
５により決定されるAD2入力レベルにより出力
ポート１からパルス幅変調したパルスを出力
し、これをオペアンプ６に積分して入力すること
によりオペアンプ６の出力レベルをパルス幅に比
例させて出力し、高圧トランス８の現像バイアス
DC成分を制御する。９はトランスであり２次側
を全波整流しオペアンプ１１によりゼロクロス検
出を行う。ゼロクロスパルスはマイクロコンピユ
ータ７の1割込端子に入力され、それによる
割込処理により第５図のルーチンプログラムによ
つてAD1入力信号を読込み、現像バイアスを制
御する。 FIG. 3 shows an embodiment of the present invention. An optical sensor DH, a photodiode in this embodiment, is installed in front of the mirror lands IM to detect the intensity of reflected light from the document glass PC. In addition, D is a photosensitive drum,
L is an original exposure lamp. Figure 4 shows the detection circuit. The detection signal from the photodiode 1 of the PH is amplified by the operational amplifier 2, the gain is adjusted by the operational amplifier 3, and the signal is input to the AD1 input of the microcomputer 7 with a built-in AD converter. The microcomputer 7 outputs a pulse width modulated pulse from the output port 1 based on the input level of AD1 and the input level of AD2 determined by the volume 5, and integrates this pulse and inputs it to the operational amplifier 6, thereby adjusting the output level of the operational amplifier 6. Outputs in proportion to the pulse width, and develops the developing bias of the high voltage transformer 8.
Control the DC component. A transformer 9 performs full-wave rectification on the secondary side, and an operational amplifier 11 performs zero-cross detection. The zero-cross pulse is input to the 1 interrupt terminal of the microcomputer 7, and the resulting interrupt process reads the AD1 input signal according to the routine program shown in FIG. 5 to control the developing bias.
第５図において各フラグ（FGで示す）とシー
ケンスとの関係は第８図に示す。まずコピーボタ
ンが押されるとメインモータが回転を初め感光ド
ラムの除電、クリーニングのための前回転を終了
すると光学系が前進を開始し原稿の先端を知らせ
る前進途中にあるセンサＳの入力により（ステツ
プ１）その画先が現像動作に至るまでの時間P1
カウンタをインクリメント開始し（ステツプ２）、
P1をカウントするカウンタP2のカウントアツプ
値により原稿先端が露光されてからその潜像が現
像されるまでの時間を測定する。尚、現像開始前
にはドラム上にトナーが付着しない様に、プリセ
ツト値FFにAD2を加算したバイアスを印加する。
（ステツプ０）その間AD1をくり返しサンプリン
グし、Ｌの値に加算し（ステツプ３）、上記時間
経過して現像中であることを示すFGがセツトさ
れると（ステツプ４）、Ｌの値をP1で割りAD1の
平均値を算出し、微調整ボリユーム５（第３図）
からの入力AD2との加算をし、この値をＮとし
（ステツプ５）、ルーチンａの第６図に示すように
Ｎの値により決まるパルス幅制御値Ｔを求める。 The relationship between each flag (indicated by FG) and the sequence in FIG. 5 is shown in FIG. 8. First, when the copy button is pressed, the main motor starts rotating, and when the pre-rotation for neutralizing and cleaning the photosensitive drum is completed, the optical system starts moving forward. 1) Time P1 until the image tip reaches the developing operation
Start incrementing the counter (step 2),
The time from when the leading edge of the document is exposed to when the latent image is developed is measured by the count-up value of counter P2 that counts P1. Before starting development, a bias equal to the preset value FF plus AD2 is applied to prevent toner from adhering to the drum.
(Step 0) Meanwhile, AD1 is repeatedly sampled and added to the value of L (Step 3). When the above-mentioned time elapses and FG is set indicating that development is in progress (Step 4), the value of L is added to P1. Calculate the average value of AD1 by dividing by and fine-adjust volume 5 (Figure 3)
This value is set to N (step 5), and the pulse width control value T determined by the value of N is determined as shown in FIG. 6 of routine a.
第６図でＮの値を30で割つてあるのは、先で述
べたＮ（←Ｌ／P1＋AD2）がＡ／Ｄコンバータが
256LSBなので最小０、最大510であり、これを
30LSB単位で分割すると18分割できるからであ
る。従つてＮ←Ｎ÷30のそれぞれの値に対し、第
４図１ポートへ出力するパルス幅を制御するこ
とにより第９図に示すように現像バイアスDC成
分を変化させることができる。現像バイアスDC
成分は第４図に示す現像バイアス制御電圧VBに
より第１０図に示すように−50〜−600Vまで変
化し、このVBを制御するためにマイコンの１
出力ポートより出力するパルス幅を制御してい
る。その制御フローチヤートが第６図、第７図に
示したものである。第７図のタイマ内部割込プロ
グラムはパワオン時にスタートし、その後自らの
タイムアツプにより割込がかかりスタートする。 The reason why the value of N is divided by 30 in Figure 6 is because the previously mentioned N (←L/P1+AD2) is 256LSB for the A/D converter, so the minimum is 0 and the maximum is 510.
This is because if it is divided into 30LSB units, it can be divided into 18 parts. Therefore, by controlling the pulse width output to the port 1 in FIG. 4 for each value of N←N÷30, the developing bias DC component can be changed as shown in FIG. 9. Development bias DC
The component changes from -50 to -600V as shown in Figure 10 depending on the developing bias control voltage VB shown in Figure 4.
Controls the pulse width output from the output port. The control flowcharts are shown in FIGS. 6 and 7. The timer internal interrupt program shown in FIG. 7 starts when the power is turned on, and then starts when an interrupt occurs due to its own time-up.
現像中FGがセツトされてからは、先で述べた
カウンタP1と第８図に示したようにバイアス演
算FGがセツトされている間ACのゼロクロス点
（INT入力信号）でカウントを続けているP2カウ
ンタの値が一致するごとに現像バイアスを切換え
ている。従つて４回制御を行う。 After the FG is set during development, the counter P1 mentioned earlier and P2, which continues counting at the AC zero cross point (INT input signal) while the bias calculation FG is set, as shown in Figure 8. The developing bias is switched every time the counter values match. Therefore, control is performed four times.
ところで感光ドラムはPCドラムであり１次
帯電がマイナス帯電であるので現像バイアスDC
成分をマイナス側に大きくすると現像量が減少す
る方向となり、複写画像が薄い画像となる。従つ
て第９図に示したようにＮの値が大きくなるに従
つて、すなわち原稿濃度が薄い方向になるにつれ
て現像バイアスDC成分のマイナス値を小さくし
ていき現像量を大きくしていき薄字再生をよくし
逆に新聞などのような濃度の濃い原稿に対しては
現像バイアスDC成分を大きくしていき複写画像
のかぶりをなくす方向の制御となつている。 By the way, the photosensitive drum is a PC drum and the primary charge is negative, so the developing bias DC
When the component is increased to the negative side, the amount of development decreases, and the copied image becomes thinner. Therefore, as shown in FIG. 9, as the value of N increases, that is, as the density of the document decreases, the negative value of the developing bias DC component decreases and the amount of development increases, resulting in thinner characters. Control is aimed at improving reproduction and, conversely, for documents with high density such as newspapers, the developing bias DC component is increased to eliminate fog in the copied image.
第４図に示すボリユーム５は第１１図に示すよ
うに、ドラムのＥ−Ｖ特性がドラムの劣化により
１曲線から２曲線に変化した時に適正な複写画像
を得るために現像バイアスDC成分を適当に補正
するための手段である。 As shown in FIG. 11, the volume 5 shown in FIG. 4 is used to adjust the developing bias DC component appropriately in order to obtain a proper copied image when the EV characteristic of the drum changes from one curve to two curves due to drum deterioration. This is a means for correcting.
なお本発明では原稿走査区間を原稿先端検知セ
ンサからの入力信号があつてから、先端画像が現
像されるまでの時間を基準に時間分割しそれによ
るサンプリングデータを演算することにより現像
バイアスを制御したが、この方法に限ることな
く、例えばその他の適当な所定の走査時間幅を基
準に走査区間を分割したり、変倍機能を有する複
写機等に関しては倍率により光学系の走査スピー
ドが異なるために所定の走査距離を基準に走査区
間を分割することによる等の制御が有効となる。
又露光直後の感光ドラム上の電位を測定してそれ
を上述の演算を行つて制御することもできる。 In the present invention, the development bias is controlled by dividing the document scanning period into time based on the time from when the input signal from the document leading edge detection sensor is received until the leading edge image is developed, and calculating the sampling data based on the time. However, this method is not limited to this method; for example, the scanning section may be divided based on other suitable predetermined scanning time widths, or the scanning speed of the optical system differs depending on the magnification in the case of copying machines with variable magnification functions. Control such as dividing the scanning section based on a predetermined scanning distance becomes effective.
It is also possible to measure the potential on the photosensitive drum immediately after exposure and perform the above-mentioned calculation to control it.
本発明により、薄字の原稿画像に対しては再現
性が良好で新聞等の濃い原稿に対してはかぶるこ
となく複写画像が得られ従来の濃度調整レバー等
の調整による手間が省け、ミスコピーによる転写
紙の無駄もなくなり効率のよい複写機能が実現さ
れる。 According to the present invention, the reproducibility is good for original images with light characters, and copies of dark originals such as newspapers can be obtained without overlapping, eliminating the hassle of adjusting the conventional density adjustment lever, etc., and making mistakes in copying. This eliminates the wastage of transfer paper and realizes an efficient copying function.
第１図は複写機の操作部を示す図、第２図は従
来の濃度調整回路図、第３図は光学系の説明図、
第４図は本発明を実現する回路図、第５図〜第７
図は本発明のフローチヤート図、第８図はシーケ
ンスタイミングチヤート図、第９図は演算値と現
像バイアスの関係図、第１０図は現像バイアス制
御電圧と現像バイアスの関係図、第１１図はドラ
ムのＥ−Ｖ特性図であり、図中PHはフオトセン
サ、Ｓは画先センサ、Ｄは感光ドラムである。
Fig. 1 is a diagram showing the operation section of the copying machine, Fig. 2 is a conventional density adjustment circuit diagram, Fig. 3 is an explanatory diagram of the optical system,
Figure 4 is a circuit diagram for realizing the present invention, Figures 5 to 7
The figure is a flow chart of the present invention, FIG. 8 is a sequence timing chart, FIG. 9 is a relationship diagram between calculated values and developing bias, FIG. 10 is a relationship diagram between developing bias control voltage and developing bias, and FIG. 11 is a diagram showing the relationship between developing bias control voltage and developing bias. It is an EV characteristic diagram of a drum, in which PH is a photo sensor, S is a tip sensor, and D is a photosensitive drum.
Claims (1)
手段、 感光体上に原稿画像に対応する静電潜像を形成
する潜像形成手段、 前記静電潜像を前記走査手段の走査タイミング
に対して所定時間遅れで現像する現像手段、 前記走査手段が原稿の先端走査位置にあること
を検出する位置検出手段、 前記位置検出手段の検出出力に応答して計時を
開始し、前記現像手段が現像動作を開始するまで
時間を計時し、記憶する第１計時手段、 前記第１計時手段が記憶している時間を計時す
る度に出力信号を発生する第２計時手段、 前記走査手段の像形成のための走査中に、前記
第２手段の前記出力信号に従つて、原稿を露光走
査方向において数個の領域に分割し、各分割領域
内で所定周期で複数回サンプリングして各分割領
域内の原稿濃度をそれぞれ検出する濃度検出手
段、 前記濃度検出手段の各サンプル値をデジタル値
に変換するデジタル変換手段、 前記分割領域の夫々について前記デジタル変換
手段の出力を加算して、前記分割領域における原
稿濃度の平均値を求める演算手段、 前記演算手段の演算結果に従つて、前記分割領
域に対応する領域部分の原稿画像を前記現像手段
が現像する際の現像バイアスを制御する制御手段
を有し、 前記制御手段は前記各分割領域の現像バイアス
を、前記第２計時手段の前記出力信号に応じたタ
イミングで切換制御すると共に、 前記演算手段及び前記制御手段は夫々演算及び
現像バイアスの制御を繰返すことを特徴とする画
像形成装置。[Scope of Claims] 1. A document table glass on which a document is placed; a scanning device that exposes and scans the document on the document table glass; and a latent image forming device that forms an electrostatic latent image corresponding to the document image on a photoreceptor. , a developing means for developing the electrostatic latent image with a predetermined time delay with respect to the scanning timing of the scanning means, a position detecting means for detecting that the scanning means is at a leading edge scanning position of the document, and detection of the position detecting means. a first timer that starts timekeeping in response to the output, measures and stores the time until the developing means starts the developing operation; and outputs an output signal every time the first timer measures the stored time. a second clock means for generating an image; during scanning for image formation by the scanning means, the document is divided into several regions in the exposure scanning direction according to the output signal of the second means; density detecting means for detecting the document density in each divided area by sampling multiple times at a predetermined period within the divided area; digital converting means for converting each sample value of the density detecting means into a digital value; calculation means for adding the outputs of the digital conversion means to obtain an average value of document density in the divided areas; and according to the calculation result of the calculation means, the developing means converts the original image in the area corresponding to the divided area. It has a control means for controlling a developing bias during development, and the controlling means switches and controls the developing bias of each divided area at a timing according to the output signal of the second timer, and the calculating means and an image forming apparatus, wherein the control means repeats calculation and control of the developing bias, respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58134841A JPS6026367A (en) | 1983-07-22 | 1983-07-22 | Image controller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58134841A JPS6026367A (en) | 1983-07-22 | 1983-07-22 | Image controller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6026367A JPS6026367A (en) | 1985-02-09 |
| JPH0555871B2 true JPH0555871B2 (en) | 1993-08-18 |
Family
ID=15137712
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58134841A Granted JPS6026367A (en) | 1983-07-22 | 1983-07-22 | Image controller |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6026367A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0746239B2 (en) * | 1985-02-25 | 1995-05-17 | キヤノン株式会社 | Copying device |
| JPH04156568A (en) * | 1990-10-19 | 1992-05-29 | Mita Ind Co Ltd | Method of detecting density of document |
-
1983
- 1983-07-22 JP JP58134841A patent/JPS6026367A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6026367A (en) | 1985-02-09 |
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