JPS59214051A - Copying machine - Google Patents

Abstract

PURPOSE:To optimize a reproduced image all the time by calculating original density with prescribed data and forming the image. CONSTITUTION:A control means 100 which measures the density of an original, controls image formation condition on the basis of the measurement result, and adjusts the density of a copy automatically processes the measured density of the original with the prescribed data to control an image forming means. This function is useful when a measurement part with an automatic density adjusting function AE takes an AE copy of an original having extremely different density, and an operation procedure is simplified when the quantity of light is stored by shifting the original intentionally or taking an AE measurement of anothr original having the same density and a copy is taken through manual proper exposure with the original set correctly, thus obtaining the copy securely with the proper quantity of light.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an image forming apparatus such as a copying machine, and in particular to automatic image density adjustment that measures the density of a document and determines appropriate image forming conditions during image formation based on the density of a document. The invention relates to a device having a function.

<Prior Art> Conventionally, in a copying machine having an automatic density adjustment function (referred to as AE), the AE measurement operation is performed before or simultaneously with the copy sequence, and even if the AE measurement result is inconvenient, the AE measurement operation is performed. , a copy could be created and cause a miscopy.

Furthermore, the AE measurement is not necessarily all-powerful, and there are some originals for which proper measurement cannot be performed (such as originals where only the AE measurement area has an extremely different density than the rest).

<Purpose> The present invention has been made in view of the above points, and an object thereof is to provide a copying apparatus capable of obtaining an optimum reproduced image.

<Example> Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a sectional view of a copying apparatus to which the present invention is applicable.

1 is the main body of the copying machine. 33 is a photosensitive drum that rotates clockwise as indicated by the arrow. Reference numeral 50 denotes a main motor, which drives all the drives including the photosensitive drum 33, the fixing device 44, the transport unit 41, the paper feed roller 38, and the optical system including the document illumination lamp 21 using a chain (not shown). ). The drum 33 is simultaneously neutralized by the pre-exposure lamp 32 and the pre-discharge charger 2, and then corona charged (for example, +) by the charger 31.

Thereafter, the drum 1 is subjected to slit exposure at the exposure point A with the image irradiated by the illumination lamp 21.

At the same time, the secondary charger 4 performs corona charge removal with a polarity opposite to that of AC or - (for example -) to form a high-contrast electrostatic latent image on the drum 33. The electrostatic latent image on the photosensitive drum 33 is then developed by the developer roller 34 of the developing device 29 and visualized as a toner image.

Here, 59 is a blank exposure lamp, which is turned on while the drum is rotating other than when exposing the original, to erase the drum surface charge in the non-image area and prevent excess toner from adhering to the drum. There is.

In addition, with the same effect, the blank exposure lamp is also turned on during small cassette and reduction copying.

A plurality of blank exposure lamps 59 are provided in the axial direction of the photosensitive drum 33. Then, the toner image is transferred to the transfer paper in the transfer charger 40, but prior to this, the paper is fed from the cassette 37 at a timing such that the leading edge of the toner image and the leading edge of the transfer paper coincide with each other. The paper is fed by the rotation of the roller 38, and the paper is sent out by the registration roller 39. At this time, the document illumination lamp 2 is used to expose the document.
The optical system including the document illumination lamp 21 scans the document in the direction of the arrow while scanning the document with the reflecting mirror 24.
, 25 , 27 .

and 28, and the image is formed on point A on the photosensitive drum 33 through the lens 26, and the entire surface of the document is exposed.

Here, 26 is a zoom lens, and when changing magnification, it moves and at the same time rotates a zoom ring to make the focal length variable. Further, a stepping motor (not shown) is used to move and rotate the zoom lens, and it can be moved to a predetermined position corresponding to a set magnification.

Reference numeral 48 denotes a registration sensor, and this sensor causes the registration roller 39 to start rotating, so that the leading edge of the image and the leading edge of the transfer paper are aligned as described above. This sensor also generates a reference signal during AFi measurement. 22 and 23 are reversal sensors, and 22B is
The cassette 37 is the optical system reversal position for a small size (for example, B5, A4 size, etc.). On the other hand, 23 is an optical system reversal position for a large size (for example, A3 size, etc.).

After the transfer, the photosensitive drum 33 is cleaned by the cleaner brush 36 of the 35-talinner section, and then electrostatically cleaned by the eraser 32 in preparation for the next charging. On the other hand, the transfer paper on which the toner image has been transferred is separated from the photosensitive drum and is transported by a paper transport section 41 toward a fixing device. At this time, the conveyance continues while being drawn downward by the suction 7-un 42. The image is fixed by a fixing roller 44 having a built-in fixing motor 77, and the completed copy paper is then discharged onto a paper discharge tray 47 by a paper discharge roller 46. 45
is a web motor that winds up a web for cleaning the fixing p-ra 44. 43 is a power transformer, and S30 is a heat exhaust fan that releases the heat of the illumination lamp 21. By the way, 49 is a potential sensor for measuring the surface potential of the photosensitive drum 33. Generally, the surface potential of a photosensitive drum is
It looks like Figure 2. The drum surface potential is charged to vO by corona discharge. Then, dark decay occurs up to exposure point A). At exposure point A, the document is irradiated by the document illumination lamp 21 and exposed to light that is generated by reflection and corresponds to the document density. At this time, if the original is pale, the amount of reflected light is large, and therefore the VL shown in Figure 2
The surface potential decreases to a point close to that point. On the other hand, when the original is dark, the amount of reflected light is reduced, and it becomes possible to determine the darkness of the original by reading the surface potential.

Note that controlling the developing bias for the original light amount X in order to determine the density of the original and obtain a properly reproduced image is hereinafter referred to as AE.

Alternatively, the same thing can be done by directly measuring the amount of reflected light from the document using a seven-point sensor to determine the lightness and darkness, and this is also called AE.

FIG. 3 is a plan view showing the operation section of the copying machine 1. FIG. In the figure, 201 is a magnification selection key, and this key is used to set the desired magnification, and the set magnification is displayed on the magnification display LED 206. Also, if the magnification setting value is changed from the original magnification, , a stepping motor moves the lens 26 to a predetermined position and also changes the focal length. Note that when the magnification is changed while the lens is being moved by the stepping motor, the movement is immediately stopped and the lens is moved to a predetermined position from the reference point again. 202
is the cassette selection key, allowing you to select two types of cassettes. 220 is a cassette size display I, which displays the cassette size of the cassette selected in ED. 203 is an AE selection key which sets the AE mode and lights up the AE mode display LED 221.

205 is a DOWN key, and 204 is an UP key, from which the copy density can be changed by a predetermined amount one step at a time. Also, by operating the key 204 or 205, the manual mode is selected at the same time, and the manual mode display L at 222 is displayed.
ED lights up. Reference numeral 215 denotes a density display, which is composed of 17 LEDs having light intensity intervals corresponding to 0.5 aperture between F1 and F9. The DOWN key 205 shifts to the left, and the UP key 204 shifts to the right by 0.5. When the power is turned on, after copying is completed, or when AE key 03 is turned on, the LED is normally displayed at the F5 position.

The number of sheets set using a sheet number setting key 207 is displayed on a sheet number display 208. 209 is a copy key, and by pressing this, a copy operation is started. 210 is a clear/stop key for clearing set numbers and stopping copying.

Reference numeral 214 is an interrupt key, and when turned on, an interrupt mode is selected and an interrupt indicator lamp 213 lights up. Furthermore, when the interrupt key is pressed again, the interrupt mode is canceled.

217 is a b toner lamp indicating that the toner is running out;
218 is a paper can lamp indicating that paper is out, 219
indicates that manual feed mode is selected,
220 is a JAM display lamp, and 221 is a counter warning lamp that indicates that there is no counter. 223 key is AE
When this key is pressed during standby with the monitor key, only the AD prescan is executed, which is used to measure the original density. Note that you cannot copy using this key.

Next, with reference to FIG. 4, a hardware configuration for controlling the person E of the present invention will be explained.

In FIG. 4, 33 is a drum, 49 is a potential sensor provided near the drum 33, and its output is connected to a potential measuring device 522.

1o o C control circuit T, ROM, R, AM and H A
/r) includes a one-chip microcomputer 100-a with a built-in converter and a D/A converter 100-.

Reference numeral 101 denotes a group of keys 1 included in the operation section of FIG.
02 is a display circuit also included in the operation section. Input to the key group 101 is by the usual key matrix method.
The signal is input to the control circuit 100, and the display circuit 102 can arbitrarily light up LEDs using a dynamic lighting circuit and lighting lamps using a lamp lighting circuit. Reference numeral 104 denotes an optical system position sensor, which is the reversal sensor (22A, 22B) shown in FIG.

23), a resist sensor (48), etc.

105 is a dip switch provided for service personnel, and 17 LEDs (Fig. 3, 21
5) is used to display check data other than the aperture value.

60 is a temperature sensor provided in the fixing unit;
08 is a volume group for adjusting AE and potential control. Further, 533 is a control circuit for controlling the lighting of the illumination pump 21, 1o3 is an optical drive device, 106 is a stepping motor for moving the lens, and 1o7 is a blank exposure lamp group (59 in FIG. 1). equivalent), and the control circuit 1o.

It is connected to the.

The microcomputer 100a described in this embodiment includes 8
It has a built-in A/D converter, which directly inputs the analog potential and adjusts the voltage between the analog GND terminal and the power supply terminal in 256 steps (sbtt).
) can be digitized with precision. In addition, there are eight analog input terminals, which are sequentially time-divisionally connected to A/
It becomes D.

Using this function, in the present invention, the surface potential of the drum, AJ
The adjustment volume value of potential control and the temperature sensor value of the fixing device (108 in FIG. 4) are directly input into the microcomputer 100-a as analog values.

This situation is shown in Figures 8 and 9.

Note that the calculation of the maximum helogen light using these AE curves is performed by the microcomputer 100 based on external input data.
-a is calculated and output as an analog output for controlling the halogen light amount value.

Further, the aperture value is calculated internally from the halogen light amount value and output and displayed on the aperture display 215.

Also, in AE correction, if the standard light amount is incorrect (
In the case where VL2=O is not achieved even after a predetermined number of control operations in the above-mentioned sight control, the corresponding correction is also performed in addition to the AE compensation. For example, if VL2=5V, the above-mentioned AE
The AE correction value is determined by taking into consideration the error 5v of VL2 in the curve to VDM.

To summarize the determining factors of these AE correction values, as described above, by measuring the surface potential VDM corresponding to the density of the original using Briscan, and controlling the lighting voltage of the illumination lamp based on that value, it is possible to An appropriate copy image can be obtained regardless of the density of the original, and the density is displayed in accordance with the density of the original.

Furthermore, when the AE mode is not selected, the drum starts rotating at the same time as the copy start key 209 is pressed, and the illumination lamp 21 lights up with a light intensity that is the standard light intensity plus the manual correction value selected by the density adjustment means. be done. after that,
The optical system starts moving forward and moves to image exposure scanning.

When variable size copying is selected using the key, light amount control is performed before entering the forward copy sequence. That is, when the copy start key 209 is pressed, if the magnification is different from the previous copy, the optical system is returned to the home position, and then the light amount control described above is performed to compensate for changes in the standard light amount due to zooming. do.

Further, in the case of the AE mode, the slope of the AH curve is changed in order to adjust the AE correction amount for each magnification. This change in the slope of the AE curve is done in parallel with the tilt adjustment volume described above, and the slope is actually a function of the adjustment volume and the copy magnification.

Further, if the fixing roller 44 reaches the first set temperature (165° C.) within a predetermined time (50 seconds) after the main 8W operation, controlled rotation is immediately started. Toner fixing temperature is 180
If the controlled rotation is started at 165°C as described above, the fixing roller 44 will be at 180°C at the end of the controlled rotation.
This button is designed to ensure that the weight has been reached, thereby reducing weight time.

It should be noted that the lens position is not limited to the same magnification position when controlling the light quantity, so the lens is fixed at an arbitrary magnification position selected before starting the control rotation, and the light quantity control is performed. Although magnification changes can be accepted using keys during control rotation, actual lens movement occurs after light amount control.

Then, by pressing the A113 selection key, AT! AE measurement by copy key 209 when J mode is selected
A series of operations leading to copying will be explained with reference to the eleventh time chart.

When AH copying is started by the copy start key 209, the lens is set at the set magnification position, and then the drum 33 is rotated and at the same time the optical system is advanced to a predetermined position.

Also, at this time, the standard light amount can be obtained from the illumination lamp 21. Lights up at standard voltage.

Next, the optical system begins to move backward (briscan), and at a predetermined timing based on a signal from the optical system position sensor 104, the microcomputer 100-a starts sampling the surface potential vDR of the drum 33.

VDλ is sampled multiple times based on the signal from the optical system position sensor 104, and the average value VDM is calculated. This sampling is performed when the latent image on the drum corresponding to a predetermined position on the original reaches the surface potential sensor, so the average value V corresponding to the density at a predetermined position on the original is
DM is now available.

After the optical system returns to the home position, the illumination lamp 21 is turned on with a lighting voltage whose standard value is corrected according to the value of VDM, and the optical system is advanced to perform image exposure. At this time, the concentration is displayed according to the lighting voltage.

FIG. 6 shows the relationship between VDM and illumination lamp correction value, and FIG. 7 shows the relationship between halogen correction voltage and density display value.

For example, when VDM=75V, that is, for a standard original, the correction value is 0, and the illumination lamp is turned on with the standard light amount during exposure of the original.

Also, at this time, the aperture display shows F5.

In addition, in the case of manuscripts with blurred texture such as newspapers, VDM is 3.
00V, and as shown in Figure 6, AE correction of about 9.6V is required, and the standard value +9.6 (
V) will be lit at the sight.

By increasing the view, the ground yellowtail will fly and a proper image can be obtained.

The aperture display value at this time is F8.5 as shown in FIG. The AE correction curve shown in FIG. 6 is often required to be adjusted depending on the machine condition or on the user's side.

Here, it is possible to input the curve adjustment amount directly into the microcomputer 100-a as an analysis amount.

Specifically, it is possible to move the AI curve in parallel (sufficient to change the standard light amount value) or change the slope of the AE curve using the volume.

The surface potential of the drum 33 is detected by a potential sensor 49 and further attenuated or level-shifted to an appropriate analog value by a surface potential measuring device 522.

Further, the temperature of the fixing device 44 is directly input in analog form to the control circuit as a potential change based on a change in resistance value of a temperature sensor 60 provided nearby.

On the other hand, the microcomputer (100-a) (D output is connected to the D/A converter (1oo-b), and its analog output is supplied to the lamp control circuit 533. The corresponding power is supplied to the illumination lamp 21.

Therefore, the microcomputer 100-a can arbitrarily set the power supplied to the illumination lamp 21, and can also set the amount of light for image exposure.

The blank exposure lamp group 107 is composed of five strands, the cross section of which is shown in FIG. 59-a Iri
B size blank, blank for B size paper smaller than A size, 59-b is 11.1 blank, R,
It lights up when there is 1 reduction, and 59-C lights up when R2 reduction is performed with R, l/几2 blank. In addition, 59-d and -e are
Turn on the standard blank when not copying to prevent wasted toner consumption. Here, in both cases, lamps are used in combination.

Further, the optical system driving device 103 can drive the optical system freely forward/backward. Further, the position sensor 104 of the optical system connected to the control circuit 100 is configured to output an output according to the position and movement of the optical system, and the control circuit 100 is connected to the control circuit 100 based on information from the plurality of position sensors. drives the optical system drive circuit 103, the registration ruler, etc.

Further, when the stepping motor 106 accepts a change in magnification using the key 101, the stepping motor 106 moves the lens to a predetermined position using a two-phase excitation method according to instructions from the control circuit 100. In order to increase the accuracy of the stopping position using a stepping motor, when stopping, it is controlled so that it always stops from the same direction at a predetermined position, and when moving to enlargement or when turning on the power,
It is controlled to move through a reference point.

Furthermore, in response to a request to change the magnification while the lens is moving, the movement is immediately stopped and the lens is positioned again via the reference point.

Next, the light amount control is started, and the document illumination lamp 21 is turned on.
A standard white plate 61 corresponding to the reflectance of the white background of the original is irradiated, and the potential (referred to as VLI) on the drum 33 is measured by a potential sensor 49.

Then, the light amount of the original illumination lamp 21 is shifted to the lamp control circuit 533 so that VLI becomes Ov.

This VL measurement control is performed three times to optimally control the light amount of the document illumination lamp 21.

The amount of halogen light such that the surface potential obtained through this light amount control becomes Ov is called the standard light amount. In other words, the light amount normally called F5 is changed from time to time in this camera by light amount control.

The standard light amount can be interpreted as the specific reference value plus the light amount control correction voltage.

Finally, VL is measured and this value is set as VL2 to end the controlled rotation. Note that this value of VL2 is used during AH control, which will be described later.

Next, the post-rotation starts, the primary charger 31 is turned off, and then,
The high voltage output of the secondary charger 4 is turned off weakly, and the secondary charger 4 is turned off after a predetermined rotation. This is to prevent unevenness in the surface potential of the drum and to stop the drum. Thereafter, in addition to energizing the fixing heater 77, the printer is also stopped, and enters a standby state awaiting manual input of the copy key.

The microcomputer equipped with the AE control of the present invention is
Not only AE control, but also copying operation and potential control functions.
It is processed within the chip.

The copying procedure will be explained below.

FIG. 10 is a time chart showing the operation when the main switch is turned on, and will be described below with reference to FIG. 11.

When the main switch is turned on, power is started to be applied to the fixing heater 77, and after a predetermined time (50 seconds), the main motor 5 is turned on.
At the same time as the drum 33 and fixing roller 44 begin to rotate, high pressure is applied to the primary charger 31 and secondary charger 4, and the pre-exposure lamp 32 and blank exposure lamp 5 are turned on.
Turn on 9. This eliminates the residual charge on the drum 33. Thereafter, when the fixing roller 44 reaches the first set temperature (165° C.), controlled rotation begins. Thereafter, the temperature of the fixing roller 44 is constantly adjusted to the second set temperature (200° C.).

The controlled rotation consists of a potential control section and a light amount control section.The potential control section measures the drum surface potential (referred to as VSL) with a potential sensor 49 while the blank exposure lamp is lit, and then starts the blank exposure lamp. With the lamp turned off, the drum surface potential (referred to as VD) is measured. VS
Based on the values of L and VD, the high voltage current flowing through the negative charger 31 and the secondary charger 4 is controlled so that it approaches predetermined VD and VSL. This control is repeated four times,
This allows stable contrast to be obtained at all times.

In this way, in the copying apparatus of the present invention, potential control, AE control, etc. are all executed in one microcomputer 100-a, input data is input from a predetermined port at a specific timing, and halogen is output as an output. The amount of light etc. is given. Therefore, a means for showing the state of data processing to the outside is required.

In this copying apparatus, the information data taken in by the microcomputer 100-a can be output to the aperture display LED using the display selection means of the dip switch inputted by the microcomputer 100-a. Depending on the settings, the drum surface potential, the drum surface potential VDM during AE measurement, and the bright area potential VIIL during potential control.

The dark potential Vn, VL2 during light amount control, etc. are displayed in binary digitization. Since this selection means is unnecessary for general users, it is not installed on the operation panel.

FIG. 12 shows an aperture display as a data display function.

00 by using the 8 LEDs on the right side of the 17 LEDs for aperture.
It shows the binary value of 256 steps up to φFF)T, and in Fig. 14 it is 01000110B (=4614).
According to the conversion table (reference diagram), the surface potential is 0■
.

In this embodiment, the aperture display is used to display the surface potential of the drum sampled at a specific timing, but the temperature of the fixing heater etc. obtained from the temperature sensor can also be displayed in the same way. It can also be used for things.

In addition to direct data, maintenance information (
The number of jams, number of drum replacements, etc.) can also be displayed here.

In addition, in this embodiment, the display device uses 17 LEDs, but the display is not limited to this and can directly display 7 segments).
It can also be applied to a display device that numerically displays the aperture using D.

Furthermore, although the display data selection means is not provided with a dedicated switch, it is also possible to use an input means using a combination of existing 10 keys, magnification keys, etc.

Further, in this embodiment, the AE monitor key 223 merely performs AE measurement and displays the result on the concentration display section, but in order to further improve operability, the AE monitor key 223 is used to
After E measurement, it is also possible to automatically shift to the manual mode, turn off the light t, and use the subsequent copy key to ensure that a copy is made with the appropriate light intensity.

This function allows the AE measurement unit to A
n This is a useful function when you want to make a copy. You can intentionally shift the original or use AE measurement to measure another original with the same density, use this function to memorize the light intensity, then set the original correctly and manually set the appropriate exposure. When trying to copy, the operating procedure can be omitted and copies with the appropriate amount of light can be reliably obtained.

Effects> As described above, according to the present invention, since an image is formed by calculating predetermined data on the original density, it is possible to always obtain an optimal reproduced image.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a copying device to which the present invention can be applied, FIG. 2 is a diagram showing characteristics of surface potential, FIG. 3 is a plan view of the operation section of the copying device, and FIG. 4 is a control section of the copying device. Block Diagram,
Figure 5 is a diagram showing the arrangement of a blank canned lamp consisting of 5+, Figure 6 is a diagram showing the relationship between the drum surface potential average value and the halogen lighting voltage correction value during AE measurement, and Figure 7 is the relationship between the halogen lighting voltage correction value and the halogen lighting voltage correction value. A diagram showing the relationship between aperture value display, Figure 8 is a diagram showing the horizontal shift of the AE correction curve due to the AE adjustment volume, and Figure 9 is a diagram showing the horizontal shift of the AE correction curve due to the AE adjustment volume.
A diagram showing changes in the slope of the correction curve; FIG. 10 is a time chart showing each operation of the control rotation after the main switch is turned on;
FIG. 11 is a time chart showing each operation of the AE measurement, and FIG. 12 is a plan view of an aperture display capable of displaying various internal data. In the figure, 21 is an original illumination lamp, 33 is a photosensitive drum, 49 is a potential sensor, 59 is a blank exposure lamp, 1
00-a is a microcomputer, 100-b is a D/person converter, and 533 is a lamp control circuit. Copy Hein FT P5 F
Box 9: LED! LE: LE [) Written amendment of cancellation procedure (spontaneous) April 48, 1981 1. Indication of the case 1981 Patent application No. 8114!1 No. 2
Name of the invention Copying device 3, Relationship with the case of the person making the amendment Patent applicant location 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (+00) Canon Co., Ltd. 5 Specification subject to amendment 6, Description of the contents of the amendment (Changes to the content) Procedural amendment written (voluntarily) Manabu Shiga, Commissioner of the Patent Office1, Indication of the case Patent Application No. 81143 of 19812, Title of invention copying device3, Person making the amendment Relationship to the incident Patent applicant address 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (100
)Representative of Canon Co., Ltd. Ryu Kaku Part 4, Agent address: 3-30-25 Shimomaruko, Ota-ku, Tokyo 146, page 6, No. 12 of the detailed specification to be supplemented and the drawings Correct "vO" in the row to "vD". (2) "X is" in the third line of page 7 is amended to "or". (3) Correct r220J on page 7, line 18 to r224°. (4) Correct the lines from line 19 on page 11 to line 8 on page 22 as shown in the attached sheet. (5) Change “Figure 14” in line 11 of page 23 to “Figure 12”.
Correct it to ``Figure''. (6) Correct "ma" in the third line of page 24 to "yo". (7) Figures 3.4 of the drawings will be corrected as shown in the attached sheet. The surface potential of the drum 53 is detected by the potential sensor 49 and further attenuated or level-shifted to an appropriate analog value by the surface potential measuring device 522. Further, the temperature of the fixing device 44 is directly input in analog form to the control circuit as a change in Fi potential based on a change in the resistance value of a temperature sensor 60 provided nearby. On the other hand, the output of the microcomputer 100-a is connected to the D/MU converter 100-1) IC, and its analog output is supplied to the lamp control circuit 533. Lamp control circuit 5
53d Power corresponding to the analog voltage is supplied to the lighting lamp 21.
It is intended to supply Therefore, the microcomputer too-a can arbitrarily set the power supplied to the illumination lamp 21, and the amount of light for image exposure can be set. Further, a blank exposure lamp group 107ij (composed of five lamps) is shown in cross section in FIG. 59-a
is a B size blank, which is for B size paper smaller than A size.
9-aFiR2 blank and lights up when R2 is reduced. Further, 59-d and -e are standard blanks and are turned on during non-copying to prevent wasteful consumption of toner. Here, in both cases, lamps are used in combination. Further, the optical system driving device 103 can drive the Fi optical system forward/backward. In addition, control circuit 1 (joK'
)? I) The position sensor 104 of the optical system outputs an output according to the position and movement of the optical system.The control circuit 104 outputs an output according to the position and movement of the optical system.
Fi drives the optical system drive circuit 103 and the registration rollers. Further, when the key of the stepping motor 106 #1101 is used to change the magnification, the lens is moved to a predetermined position by a two-phase excitation method according to instructions from the control circuit 100. In order to increase the accuracy of the stopping position by the stepping motor,
When stopping, control is performed so that it always stops in the same direction with respect to a predetermined position, and it is controlled so that it always moves through (2) the reference point when moving to enlargement or when power is turned on. Further, when a magnification change request is made while the lens is moving, the movement is immediately stopped and the lens is repositioned via the reference point. The microcomputer equipped with uninvented muE control is
Not only the system control but also the copying operation and potential control function,
It is processed within the chip. The copying procedure will be explained below. FIG. 10 is a time chart showing the operation when the main switch is turned on, and will be explained below according to FIG. When the main switch is turned on, power is started to be applied to the fixing heater 77, and after a predetermined time (50 seconds), the main motor 5 is turned on.
At the same time as the drum 33 and fixing row 244 begin to rotate, high pressure is applied to the primary charger 31 and secondary charger 4, and the pre-exposure lamp 32 and blank exposure lamp 5 are turned on.
Turn on 9. This eliminates the residual charge on the drum 53 from K. Thereafter, when the fixing roller 44 reaches the first set temperature (165 degrees), the control section (3) enters rotation. Thereafter, the fixing roller 244 reaches the 20th setting temperature (
200t? ) The temperature is always controlled so that The control rotation consists of a potential control section and a light amount control section.The potential control section measures the drum surface potential (referred to as vsb) with a potential sensor 49 while the blank exposure lamp is turned on. The drum surface potential (referred to as vn) is measured with the light off. V8L and V
Depending on the value of D, the high voltage current flowing through the negative charger 31 and the secondary charger 4 is controlled so that it approaches predetermined VD and V13L. Here, this control is repeated four times so that a stable nine-contrast contrast can always be obtained. Next, enter the light amount control, turn on the document illumination lamp 21,
A standard white plate 61 corresponding to the reflectance of the white background of the original is irradiated, and the potential (referred to as vLl) on the drum 33 is detected by the potential sensor 4.
Measure according to step 9. The amount of light from the document illumination lamp 21 is shifted to the lamp control circuit 533 so that the VLI becomes Ov. This VL measurement control is performed three times to optimally control the light amount of the document illumination (4) lamp 21. The amount of halogen light such that the surface potential obtained through this light amount control becomes OV is called the standard light amount. That is, the light intensity, which is usually called F5, is sometimes variable in this camera by controlling the light intensity. The standard light intensity can be interpreted as the addition of the light intensity control correction voltage to the specific reference value. Finally, VL is measured and this value is set as VD2 to end the controlled rotation. The value of this VD2 is A! which will be described later. Used for control. Next, turn on the rear rotation, turn off the primary charger 31, and then,
The high voltage output of the secondary charger 4 is weakened, and the predetermined rotational wave secondary charger 4 is turned off. This is to eliminate the difference in surface potential of the drum and stop the drum. Thereafter, everything except the power supply to the fixing heater 77 is stopped, and the copy key enters a standby state waiting for human power. Further, if the fixing roller 44 reaches the first set temperature (165t') within a predetermined time (50 seconds) after the main SW is turned on, controlled rotation is immediately started. The fixing temperature of toner (5) - is approximately 1, as described above.
When the controlled rotation is started at 65 mm, the fixing roller 44ij has reached 180 mm by the end of the controlled rotation, thereby shortening the wait time. Oka, since the lens position should not be limited to the same magnification position when controlling the light quantity, the lens is fixed at an arbitrary magnification position selected before entering control rotation, and the light quantity control is performed. Although magnification changes can be accepted using keys during control rotation, actual lens movement occurs after light amount control. Next, a series of operations leading to AI measurement RAM E copy by the copy key 209 when the AI mode is selected by the M E selection key will be described with reference to the time chart of FIG. 11. When AI copying is started by the copy start key 209, the lens is set at the set magnification position, and then the drum 33 is rotated and at the same time the optical system is advanced to a predetermined position. Also, at this time, the illumination lamp 21 is turned on at a standard value voltage that provides a standard amount of light (6). Next, the optical system is moved backward (briscan), and at a predetermined timing according to the signal from the optical system position sensor 104, the microcomputer 100-a moves the drum 330
Start sampling the surface potential VDR. VDR is sampled multiple times based on the signal from the optical system position sensor 104, and the average value VDM is calculated. This sampling is performed when the latent image on the drum corresponding to a predetermined position on the original reaches the surface potential sensor, so the average value T corresponding to the density at a predetermined position on the original is
I) M can be obtained. After the optical system returns to the home position, the illumination lamp 21 is turned on with a lighting voltage whose standard value is corrected according to the value of TI)M, and the optical system is advanced to perform image exposure. At this time, the concentration is displayed according to the lighting voltage. FIG. 6 shows the relationship between VDM and illumination lamp correction value, and FIG. 7 shows the relationship (7) between halogen correction voltage and density display value. For example, when VDM=75V, that is, for a standard original, the correction value is -0, and the illumination lamp is turned on with the standard light amount during exposure of the original. Also, at this time, the aperture display FiF5 is shown. In addition, in the case of manuscripts with irregularities such as newspapers, VDMij
The voltage is about 300V, and as shown in Figure 6, Alt! is about 9.6V! Correction is required, and the standard value +9.
It will be lit with the intensity of 6 gates. By increasing the amount of light, the ground yellowtail will fly away and a proper image will be obtained. The aperture display value at this time is F8.5 (see Figure 7). The AI correction curve shown in FIG. 6 is often required to be adjusted depending on the condition of the machine or on the user's side. And here, microcomputer 100-al (
It is possible to input the curve adjustment amount directly as an analog amount. Specifically, it is possible to translate the A1 curve (8) by changing the volume (this corresponds to changing the standard light amount value) or to change the slope of the All curve. This situation is shown in Figure 8.9. Oka, the calculation of the halogen sight using these Am curves is performed by the microcomputer 100-1 based on external input data.
a is calculated and output as an analog output for halogen light amount control. In addition, the aperture value (as well as the halogen light amount value) is calculated internally and output and displayed on the aperture display 215. In addition, if the standard light amount is out of order in the M X correction (
Even after the predetermined number of light intensity controls described above, VTI, 2:
(If it does not become o), K is corrected in addition to the correction key E correction. For example [VL2. ,．． If it is 5V, consider the error 5V of VL2 in VDM using the Am curve mentioned above. This determines the correction value. The determining factors of these hum E correction values are summarized as follows. (9) As mentioned above, by measuring the surface potential VDM corresponding to the density of the original using Briscan, and controlling the lighting voltage of the illumination lamp based on that value, it is possible to A copy image can be obtained, and the density corresponding to the density of the original can be displayed. In addition, when the AFj mode is not selected, the drum starts rotating at the same time as the copy start key 209 is pressed, and the light intensity is calculated by adding the manual correction value selected by the density adjustment means to the standard light intensity of the illumination lamp 21#'i. is lit. After that, the optical system starts moving forward and moves to image exposure scanning. When scaling copying is selected by the key, Kft,'! before entering the decimal copy sequence. ! control is performed. In other words, when the copy start key 2 [ ] 9 is pressed, if the magnification is different from the previous copy, the optical system is returned to the home position, the light amount control described above is performed, and the standard light amount is adjusted by changing the magnification. Correct changes. Furthermore, in the case of AFi mode, the slope of the AI curve is changed in order to adjust the amount of E correction for each magnification. This All! Changing the slope of the curve is done in parallel with the slope adjustment volume mentioned earlier, and in reality, the slope is the same as the adjustment volume (11).

Claims (1)

[Claims] (1) In a copying apparatus having a control means that measures the density of the original, controls image forming conditions based on the measurement result, and automatically adjusts the density of the copy, the control means adjusts the density of the measured original to a predetermined value. A copying apparatus characterized by arithmetic processing of data and control of image forming means. (2. In claim 1, the predetermined data is at least one of state data of image forming conditions, data of a selected copy mode, and data that varies the correlation between original density and copy density. A copying device characterized by: