JPS58153953A - Controlling method of copy density in electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To obtain a clear copy without photographic fog independently of the kind of an original, by changing the exposure and the development bias value in the dead cycle time in accordance with the reflection factor of the original. CONSTITUTION:An optical sensor 21 is provided near an entrance A of an original carrying path. Light from lamps 32 and 33 is received by photodetectors 34 and 35 to measure the reflection factor and the transmittance of an original D. On the basis of the combination of two values, it is discriminated whether the original is a transparent original such as tracing paper, an original having a high background density such as color paper and white-blanked characters, an original having a middle density overall such as a poster, or an ordinary original having a white background. The exposure and the development bias value are changed on the basis of the discrimination result in the time other than the copy cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for controlling an electronic copying machine, and a method for controlling the density of one copy by adjusting the current density and the exposure amount.
I do.

As copying machines became popular, some users began using white KJ.
IO-tai - so-called plain paper manuscript with an ink image t)
@K, originals with various 0-color backgrounds, O originals made of materials other than paper, etc. 0@Suhara S is taken as a ridge copy 9 *** is becoming stronger. A special manuscript has optical properties such as light transmittance and light reflectance that are different from a plain paper manuscript. Manuscript,
1 star [76164, 41K) Racing PΔ,
4 Smee is a paper used for drawing designs etc., and recently there have been an increase in the number of 1★ copies of Hiro Sore.

However, unlike FK, these **** originals have different optical properties from plain paper originals, and there is a significant difference in light reflectance and light transmittance in these areas. Atsuku. Then, place a white reflector on the back of the original, irradiate the original with 0111iliK light, and send the reflected light to the photoreceptor! ! If such a special original is copied on a so-called reflective copying machine that makes copies (by making copies) on 1411 as well as on plain paper, the number of copies will be 41.
When the background area density is dimmed, the image area becomes thinner and it becomes extremely difficult to see and round, such an explosion of quality cannot be created, and the copy of the background area and this background area No, due to the contrast between the density and the image area SL position.

In order to solve this problem, with conventional electronic copying machines, when copying such an Ig# original, the user must copy it! I
Original Wt) The S degree is judged by looking at the flesh layer, and that information is manually given to the copy by the user himself through the selection switch, and the copy is controlled according to the selection. 0 copy a
However, in the ζO field, there is a difference in the JI figure,
There are many cases where you have to look at the copy that has been made, add a different system selection switch, and make a new copy, which can make Hirosaku's work a lot of trouble.

Main departure @ roar, Hi O point Kl! The density of the background area is automatically controlled at the same time so that you can obtain copies with excellent image quality even if the document is not a plain paper original. This is the fourth paper that attempts to provide a method.

The present invention provides a reflectance detection means in the original insertion part of an electronic copying machine, and detects the reflectance of the background part of the original by the reflectance detection means, and detects the reflectance of the background part of the original. Compared with the standard reflectance, the development bias and exposure amount are controlled based on the development bias and exposure amount that do not correspond to the standard reflectance.
The control is designed to be carried out during the engine cycle.

In other words, as mentioned above, the copy quality is largely influenced by the contrast between the background area density of the background area and the ** area, and the contrast between the background area density of the background area and the background area am and the image area. #Contrast with Maro) a % II *
"4Kil image density can be changed by adjusting the photoconductor OII light and the 9 electrostatic charge." It is determined by the potential difference between the surface potential of the latent image and the a*-q insulator position.
Toki as normal 1! When copying with an A image, it is desirable to apply toner to the image area of the nine electrostatic latent parts formed on the photoconductor and to prevent toner from adhering to the background area. It is set 1 to take an O voltage between the *iii potential of the O image area and the surface potential of the background area. Accordingly, the developing bias potential, the image area Osign potential, and 0
Nine strong electric fields are formed between them! Since the applied toner adheres to the KOJ1% region, the 0 direction, the @ bias potential, the surface potential of the background region, and the direction of the 9 electric field stiffness due to the OMK shape are the same.
The amount of toner attached is determined by the development bias potential and the image area osui.
It depends on the voltage rise** between potential and zero, and therefore on the potential difference between them. In order to increase the contrast of the threshold between the image area and the background area of the created large copy, it is sufficient to bring the development point as close as possible to the back area 0@image potential. However, from 1k onwards, if the development bias potential is brought too close to the background area osui potential, the electric field strength becomes weak), and therefore the gravity of the toner rises to the electrostatic force, causing the toner to adhere to the background area. There is.

The image force due to the charge of the toner acts to cause the toner to adhere to the background area. Therefore, the current IIIf Ianu potential is determined in advance, taking into account the zero point.

9. If the background area OII image potential is higher than the developing bias, rounding to prevent toner from adhering to the background area and the developing bias may be set to a value higher than the background area 0II-potential. In the case of ζO field, the potential difference between the potential area O*tii and the developing bias is rounded;
1! However, since the background II value is reduced even more, the overall II value is lowered and the image quality is improved.

The 'AO'j5 method for increasing the contrast between the image area S level and the background area density is to increase the potential difference between the image area 0JJR image potential and the development bias potential. , image area 01! There are many machines that increase the field potential. The true potential of the HiOII region depends on the photoreceptor O exposure amount. That is, as the amount of exposure of the photoreceptor increases, the amount of zero reflected light from the original also increases, and the noble potential of the self-area decreases. Conversely, when the exposure amount of the photoreceptor becomes smaller, the amount of 0 reflected light from the original also becomes smaller *b, and the image potential of my area OII becomes louder. Curl up and copy the OIm area in front of you.
In order to increase contrast between direct and background areas, the amount of exposure of the photoreceptor may be lowered.

However, in this pigeonhole, the blue area OII image potential is also high<me, approaching the 1If11d Ianu potential. Background area O
When the S and S potentials approach the development (d) and insulating (I) levels, the S and O electric potentials become weak (na), and the toner's zero gravity rises to the electrostatic force, causing the toner to move into the background area. The toner may adhere to the background area due to the image force caused by the toner O charge in the bottle. Therefore, when determining the exposure amount, take these points into consideration. It will be done.
In order to prevent toner from adhering to the background area, the potential of the background area should be set at a high level. It is only necessary to keep the dovecote Ka1 exposure low and lower the am potential of the gold body.It helps in reducing the noble potential of the background area, and the osu potential of the pigeon area also decreases, Copy background area am
The image quality improves even as the image quality decreases.

Even if K is eventually formed on the photoreceptor, the Kusoden latent OII
Image potential line, O depends on the original lll01111, so O concentration lI! Also, the background area O#1 degree is very important in determining the development bias and exposure amount! Km is coming. The background area Oam of the background area Oam is determined by detecting the reflectance of the background area Oam)
can get.

t'h-1 To avoid misunderstandings, we will briefly explain the use 1 used in this book below. The printing of the manuscript is the original I.
IO Optical - IFO Abstract: In a plain paper manuscript, the image area s1 degree is the same as the snow scene area.
The oil amount area and the area, which is the so-called bottom page of the manuscript), and the original image area is the support base on the background area. ,
This is the area where one message is communicated, and is roughly divided into an open area for characters, ms, etc., and a peta crystalline area that is wide on both sides. Furthermore, the term “copy once” refers to the optical once created.)
Adhesive toner @1EK41 is something that roars. The copy of Jin is based on the above @my bias and exposure amount 0111111)
By changing the layer to an appropriate layer, you can further improve the reflectance of the background area of the original and the contrast by placing the original on a transparent surface.
A white reflector is placed on the back, and the background area of the front WA of the original is irradiated with light, and the reflected light is directed toward the photoreceptor.In the so-called side exposure knee, the amount of light incident on the original is adjusted to the photoreceptor. Defined as the ratio of the amount of incident light.

This book** has been created with the above points in mind.
It is %O that adjusts the development bias based on the reflectance of the original IIO background region. The ζO reflectance is not 4, which requires an evaluated value, but one of 01LII%.In the past, the reflectance was calculated based on the reflectance of a 1m long archipelago, and what level of reflectance was it? 0 books divided into! In I@, the development bias and exposure amount are selected in advance according to the weight resistance, and the nine originals with a certain reflectance are inserted into the copy slot. , the reflectance of the original is fixed using a weight-bearing detector placed in the insertion slot, and the development bias and exposure amount are determined based on the weight-bearing capacity of the original, and the determined development bias and The copying machine is controlled to perform development by adjusting the exposure amount.

In this way, in this invention, the optimum developing bias and exposure amount are selected according to the type of document, especially the back area of the document O, and development is performed. ♂− is obtained. However, the detection of the background area #1 of a 4h-thick original is carried out monolithically at the original insertion slot, so it is difficult to make unnecessary copies. The adjustment of the development bias and exposure amount is done during the rounding and development process, which is carried out while the round area of the photoreceptor passes through the development stage II, that is, during the development process. tk1% to have a negative impact on

Please refer to the pictures below, then go to @ for details, and then go to 114 @ for more details. FIG. 1 shows an example of an electronic copying machine to which the method of the present invention is applied.
The bale feeding equipment is being used. Manuscript - Okabu-Okiyuki is placed between O1 and P-tsu1 and these O's, and the /
It has 4 paddles. The original is inserted downward from the entry point, passes through the lower image feeder 5, passes the platen 6, is turned over, passes through the upper transport path 7, and is transported from point 8 to the original transport 114112.
(D is transported to the outside.

The photoreceptor l is supported to rotate in the direction of the arrow, and around it are a charging device 8, an exposure device 9, a developer 4! ! Feed 1G, transfer station 11, cleaning 411112, etc. are well arranged. The surface of the photoreceptor 10 is first uniformly charged by the charging device 8, and then exposed to the light intensity of the original to form a stone. In this exposure process, the original is placed on the photoreceptor 1t) 1gI@ and moved over the platen 6 at a 90-degree angle, and the original is irradiated with light by the irradiation lamp 13, and the reflected light is sent to the optical system 14. Through the photoreceptor IsK
It is performed by the benevolence it projects. Above platen 6,
There is a white reflective plate 1 in front of the conveyed original 011.
5 is dazzling, so that even if the original has a low light transmittance, such as the Tracing Eno: 1, it can be exposed sufficiently. In this photosensitive factory, a KII electronic layer is formed on the surface of the glossy photoreceptor IC).

Jin no Sei 1 City 1 is broken, soul is tamed by 10 souls, and it becomes visible as Toner's fear. Takuma mdlO has 16 4-dan Haku songs, of which 111KFijllll# rolls 17 are played by Queen T11. This loading platform a-le 17KFi
The direct power source 18 is listed. As a result, the electric field 1 of the soul Jg-rule 16 becomes the soul-a-over-, and an electric field is created at 1'4 between the voltage applied thereto and the surface potential of the electromagnetic potential formed on the surface of the photoreceptor. arise.

The voltage of the soul and electric field 7 is set at a potential that is the threshold between the 1# potential on the surface of the photoreceptor and the background potential, and near the 11' ambiguity potential. . From this K, the electric field strength in the 11I region is higher than the electric field strength in the back II region, and the direction of 7 is reversed.Therefore, the toner is attached only to the image region.

The soul 1 and r-6 are sent to the transfer 4jliI11, where they are sent through 1'4 paper*transfers approximately 19 times and transferred to the Kugosha paper. -4 jars, Toner i-play's copy:',
・I1 is sent to the electric train (not shown) by the iron 1a and the iron 1i1120, and in this fixing #11, the toner is fixed on the copy @ and the copy is completed. On the other hand, the toner-covered photoreceptor area is then sent to the clearing device 12 where it is cleaned and prepared for the next copying cycle. Insert 11
The jet 41821 detects the reflectance of the background area of the document.
is being helpful. In one example of the present invention, the manuscript is
It is divided into five categories based on the reflectance of one scenic area. One of them is a plain paper manuscript, written on white paper, wrapped in Japanese cedar etc.-1
Or, the amount of peta is larger than the area of 11-1 on the back. While the reflectance of the 9F view area is relatively thick, the surface potential of the background area of the carbon fiber on the photoreceptor is relatively low. The original species of #E2 is
Tracing E #◆ IJ with high light transparency ['4
To sum up, this generally has a light transmittance of 1111K.
It depicts the 1st podium of the TD submarine, and its back area is larger than that of the plain paper manuscript, which is 11km IIi. However, the back I area has a high light transmittance and enters the background area in a rounded manner and burns the amount of light to nine, reducing the amount of light suitable for the photoreceptor Kjl. -Lull, tracing E.
With IjA+14, which has a high light transmittance such as
The light that enters the manuscript is reflected by the reflective plate of the manuscript, creating an arc of @IIIKJ! Since the light passes through the inside of the document at the point where the light comes in, the amount of light is reduced to 7. Also, the light a on the surface bJI surface of the original is
It is also possible that the amount of light is further reduced due to disturbances and the like. I f
The background region of the document with high light transmittance, such as ttK, tracing, etc., has a relatively low reflectance, so the surface potential of the 11f region on the photoreceptor is relatively high. Further, the original type of tai 5 is a sun-filled manuscript (12ε) or a manuscript with a large background in the Ili region, such as a poster. The white rectangular stack is a more rigid manuscript in which the W horizontal rectangular area and the 1' @ area of a plain paper manuscript are reversed. It is large and its 111 hours are larger than 1 shift in 1 area. Therefore, the reflectance of the background** is extremely large, and the background area of the latent image on the photoreceptor is l! The EIi potential decreases. Some of the 4 stars I met were from the Ness, but generally they were φ-colored -
, and there is no distinction between the background area and the image area.

However, the reflectance of the original is low, and therefore its corresponding potential toward °fR is extremely small.

Although the reflection reflection emission 1i21 described in IIJ can be distinguished from the manuscript tube of such 514 types (De, for example, as shown in No. This is achieved by using them together.These 7 otosensors are designed to emit the reflectance of the background area of the can where the microscope 0 is inserted and the tip of the can, and the original position side sensor and The photosenners 30 and 31 each consist of a photodiode 32, 33 and a phototransistor 34, 35).The photodiode 32 and the phototransistor 34
The photodiode 33 and the transistor 34 are arranged on both sides with the original path 36 in between. 7 O)) The Lanzoster 34 is generated from the 2-odd diode 32 and reflected from the original OK, and the multiplication table is output.

The odd transistor 3s generates light from the photodiode 31, transmits it through the source 40, and detects the multiplication table. The combination of signals generated by this phototransistor 4.35 is false in the case of plain paper, the second original, and the 45th original, respectively, and 1
,0.0,1.0.0. This allows us to distinguish between 5 types of tanks.
Kai Iasu can be determined.

However, for the 12 originals and the 50 originals, either the background area of the copy should be lowered by 411 degrees, or the contrast between the background area of the copy (111 degrees) and the density of the image area should be increased by 1. Depending on the situation, the quality of the copy will be poor. In the present invention, this is determined based on the conventional method, and although the aIR of the background area is lower than the straightening of the image area, as in the original 42, the background area of the incoming original (41M
For those relatively smaller than Ie, K al II /
4 ias and 4 lights 11 - dove -. On the other hand, as in the case of the background area 111 and the background area 111, as shown in 3. Write one verse.

Refer to the diagram and read this! @do. stripes 5
The figure shows the relationship between the developing area 440 and the photoreceptor 41.
It consists of. 44 is the fAmIeias saliva pressure source. This indicates that the nine electrostatic layers formed on the photoconducting sensitive surface are positively charged images, and that the toner is negatively charged. Therefore, a positive voltage is applied to the 3A image electrode 4i40. The photoconductive 11I surface has a charge amount of &5
1111 tables of various sizes are formed. Referring to Table 4-4, which shows this example, the M4 image voltage v8 is calculated as follows: v
S and the 1/& direction area Vl of the background area. As shown in Figure 4, the image potentials v1, vls
vS and Kaiiasu voltage v8 and 4D11th place V
t-Vs, V, -Vl, V, -Vl According to K, the electric power of 90% is 1i11kv1, v2, vs to vB K.
Therefore, each image potential is formed in the member-charged toner 45 according to the number of electric cars, and it adheres to the circular photosensitive V# surface. However, since the background potential V, and the asymmetry pressure V@, are low, the negatively charged toner adheres to the enlarged image electrode 1i and does not adhere to the front region. JII 4ml is normal I
11#Use complement A to show *4 go fVB = 20
0 V, Vl, v2sV! I > VB, VB
K < VB (for example, VQKW67V).

On the other hand, -5- indicates the at potential when using the original manuscript of 9@2 and the tracing page/parable mentioned above, and so-1 chapter potential V, 1 >200V ( For example, V
= 257 V). This name, VB=20+IV
In the case of KL9, dfJ* of the created copy decreases because 4 toners adhere to the background area. Therefore, in this case VB > VBK (9 For example, VBK”510
1 so that V)! All! / Adjust the armpit and exposure amount by 14IB. In other words, increase the power supply voltage and the amount of light. Because of this K, the potential difference Vt in one region
' -VBI, ■2' -vB1, vs'-vsi
teeth! However, since toner does not adhere to the 1f area and the copy O back area becomes low, the 1 quality improves and it becomes very easy to see.

Furthermore, Sense 61111 shows the am potential when using the third manuscript 9 mentioned above, for example, Shiranu Kawaho, and in this case, the back mass potential vIIK is higher than the keyaki area potential V. ＾I. In the case of such & manuscripts, increase the contrast with the copy & seven background mackerel area # degree and make it easier %/%
Rounding off, let be the potential Vs of the visual region and the pressure VB of the Iasu region
It is preferable to increase the potential difference VB with -V.However, the voltages VB and V are adjusted so that they approach each other. In other words, by lowering the voltage (Vsz) and lowering the exposure amount, the current potential including the current potential is increased (v'1 v
ilK 8 points). It is preferable to set the background area and the background area low, and the exposure amount to be low, even if there is an original mK where there is no clear distinction between the background area and the background area, and there are many intermediate areas, such as in the case of a III star. As a result, the areas of low density of the original are further reduced to Km<114, and the areas of low density are printed even lighter.

7 to ν#41 & exposure amount adjustment, ha), irradiation lamp 130
□ is performed by increasing the amount of light by 14jI. The light intensity of this irradiation lamp 13 is 1WA, and the power supply voltage (
- not shown) K-type proportional, 4E of irradiation run f13
- is a variable power supply, and the amount of exposure is adjusted by changing the power supply voltage. Part. The IA image Pianu electric 81g is also variable type, and its voltage YrR
Depending on the voltage, the voltage -/f is selected on a four-to-one basis. All of these power supply voltage regulators are controlled by *i*o control armor control. This control is performed during the dead cycle of the continuous copying cycle, that is, during the development/adjustment phase. At this time, in the exposure filter, there is a 4-light f! - is carried out at the time when yt passes. A set of information regarding the optimum exposure amount and current bias is input into the control device in advance according to the reflectance of the woodcutter's original.

When the reflectance of the gland can be detected by the reflectance detection amount, the information 411 is given to the front e-control device, and based on that information, the information on the development/4-irradiation and exposure amount stored in advance is sent to the e-control device. With this consideration, the jJ image bias voltage source and the irradiation lamp 11111 are controlled by fI4, and the desired light intensity and exposure amount are obtained. When this happens, the surface potential of the 11L potential is shown to move vertically parallel to it, but in actual order, the lattice potential in the dorsal** area (the area with low I!1 surface potential) ) is the change in the area IfiIE (I!
It is not so large compared to the amount of change in the I-directed potential range), and when controlling the exposure amount tube, the 4111 point is also
It is preferable to do so.

The above is an explanation of the practical aspects of the present invention. For example, non-4-d
, -1 Not only is it commonly used in the 4th edition of the original Kozue Circulation style as shown in Figure 1, but also the original II from the simple KJtlfuku insertion slot to the t Latin is self-mrsb-. It can also be used with Hinatake's copy machine. Furthermore, the same reflection and tube as the nine reflection tubes placed on the back of the original manuscript of the Hara Shakukin study may be used to create a transparent plate photo seven-nare tube 44. Top 1! J! In the usual case, the glands are divided into tS species, and the glands are divided into more cisternae.
ζ, and 4 possible. In this case, KFi is achieved by using a high-velocity reflex sensor and dividing its output into several stages. There are various types of exposure, tracing base, etc., and the above-mentioned bias control and exposure setting are not necessarily preferable. l,
It is also a good idea to detect not only the reflectance of the rear ** area but also the reflectance of the * area, and also detect the area of these areas, and set the most appropriate M4 bias and exposure amount for the document.

As mentioned above, according to Book 4 @ Ming, depending on the tank @ of the manuscript,
Since the moth's soul and exposure are set, one of the nine copies created will be directed. Furthermore, since changes in the settings of kA, paddle, and exposure are performed during the dead cycle of the slow d copy cycle, they do not affect IA*ttcm. In addition, in the present invention, each of the 41 umbrellas and the l1ljt quantity is not controlled by -t+Q m by a single d, but they are simultaneously controlled by 114-, so each of the 14 parties is independently controlled by II4. Compared to the method of controlling copy II 4 degrees, the amount of change in developing bias and exposure amount is small, and it is possible to obtain a suitable product according to a wide variety of materials. :l d) Gold production can now be controlled.

[Brief explanation of the drawing]

Fig. 1111 is a schematic diagram of a photo camera in which the method of firing is changed. FIG. 42 is a schematic diagram showing an example of a document sheet with a reverse weight-bearing capacity and side-extrusion for use in carrying out the method O of the present invention. #15 is a schematic diagram showing the potential relationship between the soul and the photoreceptor. JllI411. II145m1kUMt4EF1 is a schematic diagram showing the principle of the overlapping method. 1...stop feeling, 2-m1@1IIJIII, 6-
f 5 f n, 8...Electrification setting, 9...Akkoujiki turtle, 1G-...3J meeting pupil, 11...Transfer setting, 12.
...Cleaning ##, 17...a-roll, 18...fI
A11II bias voltage source, 30...Reflection-food sensor, 31...a transfer photo sensor, 40...m*
*Pole, 42-... photovoltaic layer, 43... conductive layer, 44-
...Structure-J4 Ias voltage-146...Toner. Figure 1 421- Figure 2 Figure 3

Claims (1)

[Claims] A reflectance detection means is installed in the insertion part of the electronic copying machine, and it works! The Otori 110W view area O reflectance is detected by the detection means, and the detected nine anti-weight resistance is compared with the reference O anti-weight resistance, and fAII/ A multi-degree control scheme is used to control the f-axis and exposure amount, and control the printing fa-diameter and exposure amount to be performed at the time of the putative site.