JPS59198472A - Copying device - Google Patents

Abstract

PURPOSE:To reduce the generation of copy failure to a minimum at an automatic density adjustment time by permitting the release of an automatic density adjustment mode, which can be selected together with a manual density adjustment mode, even during the copying operation. CONSTITUTION:The control of the quantity of light of an original or a developing bias and the similar control executed by detecting the reflected light of the original directly are called AE. A flow chart (i) setting and displaying the quantity of light indicates the setting manner of an adequate quantity of light in AE measurement, and a flow chart (ii) indicates the correcting manner with two kinds of shift key. In this flow chart (ii), the AE mode is released immediately by the depression of a shift key during copying, and back shift by 0.5 in the correction direction is performed to change the quantity of light of exposure. If the device is in the stand-by state, an AE flag is set in case of the AE mode, and the mode is switched to the manual mode, and an aperture value is not changed. If the manual mode is already set, shift is executed at intervals of each prescribed time.

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 an automatic image fidelity adjustment system that measures the density of a document and determines appropriate image forming conditions during image formation based on the density of a document. The present invention relates to a device having the following functions.

BACKGROUND OF THE INVENTION Conventionally, the density adjustment of copying machines has generally been carried out using a manually variable aperture lever, e.g., from F'1 to F9, or a stepped selection means, e.g., "dark", "normal", "
This was done by selecting "Pale".

However, in the case of these manual density adjustments, if the document has a dark background color, such as newspaper, diazo copy paper, color paper, etc., if the density adjustment is set to the standard state and the copy is made, the development of the copying device will be slow. If the color is one color (for example, black), the background color of the original is the same color as the text, and the entire surface of the copy paper will be uniformly stained. A phenomenon called "Capri" occurs. On the contrary, in the case of a document with extremely thin character density, for example, in the case of lead-forged light apricot characters, a phenomenon occurs in which the characters are skipped.

To avoid this, the density setting volume is generally set at F8 to F9 in the former case (F3 to F4 in the latter case) based on a certain degree of anticipation, or
The copy was set to ``light'' (or ``dark'' in the latter case).

However, even in this case, in order to obtain an optimal copy, the user must rely on the experience gained from copying the same type of original multiple times, which may lead to copy errors.

In order to solve these problems, copying machines with automatic quality adjustment have been developed in recent years.

In general, this type of apparatus automatically adjusts the anchorage to 1tμ by reading the density of the original and automatically adjusting the exposure amount or the development level of the developing means.

In this case, if the background color of the original can be detected perfectly, the density adjustment will be appropriate, but it is very difficult to detect the background color of various types of originals, and in general, it is difficult to detect the background color of the original. Detection of the average concentration has been carried out. Therefore,
Even when automatic foundation jW adjustment is performed, it is difficult to cover all of the various types of originals, and mistakes may occur.
There is a possibility that Furthermore, the appropriate density level set by the copying device may be different from the level desired by the user. For these reasons, even in copying machines with automatic one-time adjustment, there are still cases in which manual quality adjustment must be performed.

OBJECTS The present invention has been made in consideration of the above points, and an object of the present invention is to provide a copying apparatus with improved operability of the density σ4 adjustment function.

Furthermore, the present invention provides a copying apparatus that can minimize the occurrence of copy mistakes during automatic feed adjustment as described in 4iJ by making it possible to cancel the eye movement adjustment mode even during copying operation. The purpose is to provide

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. 53 is a photosensitive drum that rotates clockwise as indicated by the arrow. 50 is the main motor, 3
3, 44 fixing device, 41 transport section, 58 paper feed slot ~
All drives, including the drive of the optical system including the document illumination lamp 21, are performed by a chain (not shown).

Further, 31 is a high voltage charger. This charges the daylight-sensitive drum. After the exposed electrostatic latent image is formed at point A, toner is attached to the developing roller 34 in the developing device 29 and the image is visualized. Then, the toner image is transferred to the transfer paper in the transfer charger 40, but prior to this, the cassette 67
The paper is fed by the rotation of the paper feed roller 38, and the paper is sent out by the registration roller 69. At this time, the original is exposed to light by the 21 original illumination lamp.
The optical system including 1 scans the original in the direction of the arrow, and forms an image at point A on the photosensitive drum 33 via reflecting mirrors 24, 25, 27 and 28, and a lens 26, and the entire surface of the original is exposed. 48 is a registration roller, and this sensor causes the registration roller 59 to start rotating.
As described above, the leading edges of the images are made to coincide with each other, and a reference signal is also generated when measuring Am. 2
2 and 23 are reversal sensors, and 22B is an optical system reversal position where the cassette 67 is of small size (for example, B5, A4 size, etc.). On the other hand, 23 is large size (
For example, this is the optical system inversion position for A3 size, etc.).

After the photosensitive drum 63 has been transferred, it is cleaned by the cleaner brush 36 in the IJ section 55, and then the eraser 53 is cleaned.
2, it is statically cleaned by '1j-j' and prepared 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 fan 42. The image is fixed by the fixing roller 44, and the completed copy paper is then discharged onto the paper discharge tray 47 by the paper discharge roller 46. 45 is a web motor that winds up a web for cleaning the fixing roller 44. 43 is a power transformer, and 3o is a heat exhaust fan that dissipates heat from the lamp 21. and Niro de 49,
This is a potential sensor for measuring the surface potential of the photosensitive drum 35. Generally, the surface potential of a photosensitive drum is as shown in FIG. Due to corona discharge, the drum surface potential is vO
charged up to. Then, dark decay occurs up to exposure point A).

At exposure point) A, the original is illuminated by the original illumination lamp 21, and light corresponding to the density of the original is reflected by y.
S light 5 is done. At this time, if the document is pale, the amount of reflected light is large and the surface potential drops to near VL (d) shown in Figure 2.On the other hand, if the document is tired, the amount of reflected light decreases and the surface potential decreases. By reading it, it is possible to determine the darkness of the document.

Note that controlling the JA Wako amount or the developing bias (in order to determine the density of the original and obtain an image of proper reproduction) is hereinafter referred to as AE. The same thing can be performed by directly measuring the amount of reflected light from the original using a seven-point sensor and determining the lightness and darkness, which 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, which is used to set a desired magnification, and the set magnification is displayed on a magnification display LED 206. A cassette selection key 202 allows selection of two types of cassettes. A cassette size indicator 220 displays the cassette size of the selected cassette. 203 sets the AE mode with the AE selection gear, and the AE mode display LE of 221
D lights up. 221 is the DOWN key, 204 is the UP child key, and the Toreyo Shikobi anchorage can be changed one step at a time. At the same time, the manual mode is selected and the manual mode display LED 222 lights up.

Reference numeral 215 denotes a tack strength indicator, which is comprised of 174 LEDs with light intensity intervals corresponding to 0.5 aperture between F1 and F9. DOW
The N key 221 shifts to the left by 0.5, and the UP child key 04 shifts to the right by 0.5.

When power is turned on or after copying is completed, or AE key 20
When 3 is inserted, the LED is normally displayed at the 15 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. 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 indicates that the toner has run out. Toner lamp 218 is a paper fish lamp 219 indicating that paper is out.
indicates that manual feed mode is selected. A manual feed lamp 220 is a JAM display lamp, and 221 is a counter warning lamp that indicates that there is no counter.

Next, control of A of the present invention will be explained with reference to FIG. 4 and subsequent figures.

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. 100 is a control circuit, a 1-chip microcomputer 1o built in ROM and RAM.
ob, and an A/D converter 100-a and a D/A converter 100-e. 535 is a lamp control circuit, 21
is a lighting lamp connected to it. .

Reference numeral 101 denotes a group of keys 102 included in the operation unit shown in FIG.
is a display circuit included in the operation section of FIG. 3 mentioned above. Inputs from the key group 101 are inputted to the control circuit 100 using a normal key matrix method, and the display circuit uses a dynamic lighting circuit to arbitrarily light LEDs, and a lamp lighting circuit to arbitrarily light lamps. It looks like this.

103 is an optical system driving device, and 104 is an optical system position sensor, both of which are connected to the control circuit 100.

Is the surface potential of drum 33 a potential sensor? 49, and is further subjected to appropriate analog value output VAK conversion by the surface potential measuring device 522.

This analog value is the φ converter 10Q-a connected to it.
Digitized microcomputer-1
00-b can take in that digitle value.

That is, the microcomputer 1oo-b is configured to be able to take in the surface potential of the drum 55 at any timing. On the other hand, microcomputer-10
0-b (7) The output is connected to the D/A converter 100-c, and its analog output voltage VA' is output to the lamp control circuit 5.
Fart fed. The lamp control circuit 533 supplies the illumination lamp 21 with a voltage corresponding to the analog voltage A'. Therefore, microcomputer-i oo-b
arbitrarily sets the voltage supplied to the illumination lamp 21. In other words, the amount of light for image exposure can be set.

Reference numeral 103 denotes an optical system drive device connected to the control circuit 100, which can drive the optical system forward/backward. Again 1
04 is an optical system position sensor connected to the control circuit 100, which outputs a predetermined output according to the position of the optical system, and the control circuit 100 can stop the optical system at a predetermined position or return it to the home position. It is now possible to do so. Also, it is possible to sense when the optical system has arrived at a predetermined position.

An embodiment of the AE sub-control of the present invention will be described below.

First, a case will be described in which the AE key 203 is pressed and the AE mode is selected.

When the copy button is pressed, the drum 33 is rotated and at the same time the optical system is advanced to a predetermined position. At this time, the illumination lamp 21 is turned on at a standard candy voltage.

Next, the optical system begins to move backward (prescan), and at a predetermined timing, the microcomputer-100-'bH and the drum 33
Begin sampling the surface potential vp of .

VD is sampled for multiple days 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 that an average value VDM corresponding to the density at a predetermined position on the original can be obtained. It looks like this.

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 VDMQ value, and the optical system is advanced to perform image exposure. At this time, the concentration is displayed according to the lighting voltage. FIG. 5 shows the relationship between VDM and the illumination lamp correction value, and FIG. 6 shows the relationship between the lighting voltage and the density display value in FIG.

For example, VD? When A=75 V, that is, for a standard original, the correction value is 0, and the illumination lamp is lit at the initial setting value during exposure of the original. Also, at this time, the display d: ″F
5"'. Also, in the case of originals with blurred soil strength, such as newspapers, the VDM will be approximately 400■, and the illumination lamp during exposure will be lit at the standard value +5V, increasing the light amount and therefore increasing the soil strength pre-print. You can fly and get a proper image.

As described above, by measuring the surface potential corresponding to the rotation of the original by prescanning and controlling the lighting voltage of the illumination lamp based on the measured value, an appropriate copy image can be obtained regardless of the type of original. Further, a density display corresponding to the originality of the original is displayed.

On the other hand, when the Am mode is not selected, the drum begins to rotate at the same time as the copy key is pressed, and the illumination lamp 21 is turned on at the voltage set by the density adjustment means.Then, the optical system begins to move forward and exposes the image. Move on to scanning.

FIG. 7 is a flowchart regarding scene setting display among the operations of this copying apparatus.

Part (1) shows a method for setting an appropriate sight using AE measurements, part (11) shows a correction method using two types of shift keys, part (iii) shows a method for switching to AE, and part (11) shows a method for switching to AE.
) shows the light intensity setting method using the interrupt key, and (V)
The light intensity setting method using auto clear (return to standard mode) is shown in section 2.

The flow will be explained below following the steps No.

(1) shows the aperture setting for an appropriate scene based on AE measurements.

When AB copy is executed using the copy start key,
After the AE measurement, the AX correction value is calculated by measuring the drum potential a predetermined number of times. After this, the corrected light 1 (referred to as AP light amount)
Use to illuminate the original and start AE copying.

At the same time, the correction value is converted into the aperture value and displayed on the copy density display section shown at 215 in Figure 3.

(11) shows the light amount setting operation using the shift key.

Change the exposure light amount.

During standby, if the camera is in AFi mode, it will set AE 7 lag and shift to manual mode, and the aperture value will not change.

Furthermore, if the mode is already manual, shifts are performed at predetermined time intervals.

Here, the rear retimer is a timer for shifting the rear value at predetermined time intervals when the shift key 204 or 205 is held down, and if the shift key 204 or 205 for which the basic step time is set is not pressed, , the corresponding timer is set to the end value and is configured to shift each time it is pressed. Further, in step e, the aperture value is prevented from shifting when the shift keys 204 or 205 are pressed at the same time. It is also assumed that both ends of the aperture value are regulated by limiters and are set by -1 within the range of F1 to F'9.

Further, if the shift key 204 or 205 is not pressed, the aperture value is held. (iii) shows light intensity setting using the automatic density adjustment key.

During copying, changing to AFi mode using the AE key is prohibited.

Also, during the non-copy period, the AH flag is reset and changed to AE mode, and the subsequent display becomes F5.

In addition, after copying starts and before the first paper feeding, A
11i mode is permitted.

Furthermore, at the end of copying, a change to the AI mode is permitted when the optical system starts to move back for the final copy of the preset number of sheets.

(1 indicates the scene setting by the interrupt key. When the interrupt key is input, it is determined whether it is already in interrupt mode, and if it is in normal mode (non-interrupt mode), it is switched to interrupt mode. The mode classification is AE/manual, and the aperture value is R of Microcomputer 100-b.
Stored on AM.

Also, AM mode is defined as a new mode (AFi
F5 (standard light intensity) is selected for the aperture display.

On the other hand, if it is in the interrupt mode, the interrupt mode is canceled by manual operation of this key, and the aperture value is returned to the specified mode (AM/manual) before the interrupt.

(V) shows the light amount setting means by auto clear operation, and the auto clear timer counts up at a predetermined speed in a part of the flow (not shown), and when a predetermined time has elapsed after the last copy is reversed, the auto clear timer is automatically cleared. (return to standard mode). At this time, the AE flag is reset and the aperture display value is F5 (standard exposure) in AFi mode.
shift to.

As shown in each part of the flow, this auto-clear timer is configured to return to the initial value and restart the count-up when various keys are pressed and copying is completed.

Also, if you are in interrupt mode when this auto clear function is executed, return to normal mode and then
Return to mode.

If the AE key and the up or down key are turned on at the same time, the up/down key will be entered with priority.

Therefore, manual operation is possible even if the AE key is malfunctioning.

Also, if you turn on the up key and down key at the same time, no key entry will be made.

Effect: Canceling the automatic density adjustment mode and manual density adjustment can be performed using the same manual means, and furthermore, when the copying machine is not copying,
It is possible to cancel automatic density adjustment mode while maintaining the anchorage set during automatic ridge adjustment, and the automatic density adjustment mode can be canceled without complicated operations by the operator.
Further, during the copying operation, the density can be quickly changed, and a copying apparatus with greatly improved operability can be realized.

In addition, the standard copying density level is set by inputting to the automatic density adjustment mode selection means, which allows multiple inputs to the manual density adjustment means or continuous input for a long time when performing multi-stage copying with two levels at a time. This eliminates troublesome operations such as the above, and improves the operability of the copying apparatus.

In addition, since the copy density adjustment value is controlled by the amount of change in the input of the manual one-time adjustment means, the same density can be maintained even after the automatic density adjustment mode is canceled, and when continuous copy is temporarily canceled and fine adjustment is performed, the final copy To continuously change the density on paper,
It is possible to minimize the occurrence of copy mistakes.

In addition, the AE mode is automatically selected by interrupt input,
By being compatible with the standard mode, for example, when it is desired to select the AE mode, the operation of pressing the AE mode selection key is omitted. Also, even if you want manual mode, the standard density will be set regardless of the density before selecting interrupt mode, so if you use a standard original (usually used often), , the desired concentration can be easily set.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a copying apparatus to which the present invention can be applied;
3 is a plan view of the operation section of the copying device, FIG. 4 is a block diagram showing the control section of the copying device, and FIG. 5 is a diagram showing the surface potential in AE mode. potential average value,
FIG. 6 is a diagram showing the relationship between the illumination lamp lighting voltage correction value and FIG. 7 is a flowchart showing the flow of control according to the present invention. In the figure, 1 is the main body of the copying machine, 211 is an illumination lamp, 55 L is a photosensitive drum 44, and L is a potential sensor 100 is a control circuit. Procedural amendment (method) 1 Indication of the case 1982 Patent Application No. 75255 2, Name of the invention Copying device 3 Person making the amendment Relationship with the JT case Patent applicant Location 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (+00) Canon Co., Ltd. July 26, 1981 (shipping date) 0 Correction of the specification subject to amendment 7, amendment contents statement (no change in content)

Claims (1)

[Claims] A copying machine having a manual density adjustment means for manually adjusting the density of a copy, and a means for measuring the density of a document, controlling image forming conditions based on the measurement result, and selecting a mode for automatically adjusting the density of a copy. A copying apparatus characterized in that an automatic density adjustment mode can be canceled during a copying operation.