JPH0370224B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an image processing device.

Conventionally, various surface potentials of a recording medium are detected, and according to the detected values, a process means for image formation is controlled so that the surface potential becomes a predetermined value. Efforts are being made to optimize image forming conditions. However, the density of the formed image may not be appropriate. In that case, each part of the device must be checked using special measuring instruments to find the cause.
This method has the drawback of requiring a great deal of time and effort.

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned drawbacks, and aims to provide an image processing apparatus such as a copying machine, in which abnormalities in the apparatus related to image density can be easily investigated.

That is, the present invention includes a process means for forming an image on a recording medium, detection means 56 and 57 for detecting the surface potential of the recording medium, and an A/D converter for converting a detection signal from the detection means into a digital signal. In order to optimize the image forming conditions related to the D conversion means 58 and image density, when controlling the process means prior to forming an image on the recording medium, the detection means controls the process means. Converting a detection signal detected for control into a digital signal by the A/D conversion means, performing a predetermined calculation on the output, and controlling the process means according to the calculation result. A digital computer 41 that outputs a control signal 49, a display means 61 that displays numerical values, and reference potential generation means CH1, CH2 that generates a reference potential.
inputting the detected surface potential to the A/D conversion means while detecting the surface potential of the recording medium by the detection means when the control of the process means for optimizing image forming conditions is not being executed; a first display mode in which the output of the A/D conversion means is displayed on the display means, and a reference potential generated by the reference potential generation means is inputted to the A/D conversion means; display switching means SW1, SW6 to SW8) for switching between a second display mode and a second display mode in which the output of the digital computer is displayed on the display means; An object of the present invention is to provide an image processing device that operates.

In this way, by changing the type of potential input to the A/D conversion means and displaying each potential, it is possible to quickly identify abnormalities in the device related to image density with simple operations, especially input to the microcomputer. You can easily check for abnormalities on the side.

In addition, since the operation of the potential detection means is stopped when inputting the reference potential to the A/D conversion means, the adjustment to make the output of the A/D conversion means appropriate can be made accurately without being affected by unnecessary signals. This makes it possible to perform optimal image formation.

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

The surface of the drum 11 is made of a three-layer photoreceptor using a CdS photoconductor, is rotatably supported on a shaft 12, and starts rotating in the direction of an arrow 13 in response to a copy command.

When the drum 11 rotates to the normal position, the document placed on the document table glass 14 is illuminated by an illumination lamp 16 that is integrated with the first scanning mirror 15, and the reflected light is used for the first scanning. Mirror 15 and second
It is scanned by a scanning mirror 17. First scanning mirror 1
5 and the second scanning mirror 17 move at a speed ratio of 1:12, so that the original is scanned while the optical path length in front of the lens 18 is always kept constant.

The above reflected light image shows the lens 18 and the third mirror 19.
After passing through the fourth mirror 20, the exposure section 21
Then, an image is formed on the drum 11.

After the drum 11 is charged (for example, +) by a primary charger 22, an image irradiated by an illumination lamp 16 is slit-exposed in the exposure section 21.

At the same time, AC or primary charge removal with a polarity opposite to that of the primary charge (for example, -) is performed by a charge remover 23, and then a high-contrast electrostatic latent image is formed on the drum 11 by full-surface exposure using a full-face exposure lamp 24.
The electrostatic latent image on the photosensitive drum 11 is then transferred to a developing device 25.
It is visualized as a toner image.

The transfer paper 27-1 or 27-2 in the cassette 26-1 or 26-2 is transferred to the paper feed roller 28.
-1 or 28-2, the rough timing is taken by the first register roller 29-1 or 29-2, and the second register roller 30
The photosensitive drum 11 is sent out in the direction of the photosensitive drum 11 with accurate timing.

Next, while the transfer paper 27 passes between the transfer charger 31 and the drum 11, the toner image on the drum 11 is transferred onto the transfer paper.

After the transfer is completed, the transfer paper is guided to the conveyor belt 32, and then to a pair of fixing rollers 33-1, 33-2, where it is fixed by pressure and heat, and then discharged onto the tray 34.

After the transfer, the surface of the drum 11 is cleaned by a cleaning device 35 made of an elastic plate, and the process proceeds to the next cycle.

In addition, in Fig. 1, TK indicates a numeric keypad (numeric keys from 0 to 9) for inputting the number of copies, and the numeric value entered using this numeric keypad is displayed on the display 61, and the copying machine responds to the entered number n. By repeating scanning of the original as many times as the number of responses received, n copies are made.

FIG. 2 shows the control circuit of the above-mentioned copying apparatus, in which 40 and 41 are master and slave microcomputers, the master computer 40 controls the copying process, and the slave computer 4 controls the copying process.
1 is for optimizing and displaying the condition settings for the process units 45-48.

The master computer 40 and slave computer 41 are connected by signal lines 42 and 43, the signal line 42 is for sending data from the CPU 40, and the signal line 43 is for sending a strobe signal from the CPU 40. From the CPU 40, a high voltage primary transformer 45 supplies high voltage to the primary charger 22, a high voltage secondary transformer 46 supplies high voltage to the static eliminator 23, a lamp circuit 47 supplies lighting power to the illumination lamp 16, and a developer via a signal line 44 from the CPU 40. A control timing signal is sent to control the operation of a process unit such as a developing bias transformer 48 that applies a developing bias to the device 25. The process unit 45~
Reference numeral 48 is configured to output a voltage according to the outputs of digital/analog converters (D/A converters) 50 to 53;
A digital data control signal is sent from the CPU 41 to the A converter via a signal line 49 in order to control each process unit 45 to 48 in order to optimize the surface potential of the drum 11.

The CPU 41 is provided with a clock generator 55, and the clock signal generated by the clock generator 55 is of course used as a clock for the CPU 41 itself, but it is also transmitted via the signal line 54.
It is supplied to clock synchronized D/A converters 50 to 53 and is also used as a clock source for the D/A converters. In this way, using the clock generator 55, the CPU 41, D/A
Since the converters 50 to 53 are driven, the number of circuit parts can be reduced and reliability can be expected to be improved.

Denoted at 56 is a sensor for measuring the surface potential on the drum 11, the output of which is connected via a measuring unit 57 to a channel CHO of a multiplexer 59. The measurement unit 57 applies a measurement potential to the multiplexer when a sensor drive signal is applied from the CPU 41 via a signal line 62. The multiplexer 59 has channels 0 to 3, and channel CH1 has an O(V) potential, and channel CH2 has an O(V) potential.
The output voltage of the lamp circuit is applied to channel CH3, and one of CH0 to CH3 is selected and applied to the A/D converter 58 to convert the resulting digital signal. It is configured so as to be incorporated into the CPU 41. In addition,
CH1' to CH3' are provided corresponding to channels CH1 to CH3, and each channel
Since the LEDs LC1 to LC3 provided for CH1' to CH3' light up in response to the channel selected by the multiplexer 59, it is possible to confirm at a glance which channel is currently selected.

The operation of the multiplexer 59 is controlled by a control signal applied from the CPU 41 via a signal line 63.

Reference numeral 60 indicates a display circuit driver that forms a display signal based on the signal sent through the signal line 64, and controls the program execution display using seven LEDs, LD1 to LD7, and the numerical display on the display 61. be.

Here, LD1 lights up when a program that calculates a surface potential control value by reading the strong light from blank exposure is executed, and LD2 lights up when a program that calculates a surface potential control value based on the dark area potential of the drum is executed. It lights up when the
LD3 and LD4 light up when a program that calculates the surface potential control value based on the potential of the bright part of the drum is executed, and LD5 lights up when the strobe signal is derived onto the signal line 43. LD6 is lit when the copying machine is executing the reduction copy mode program, and LD7 is lit when the copying machine is executing the post-rotation program.

The display device 61 has a negative display segment 6.
1-1, Japanese character segments 61-2, 61-3 that display numerical values from 0 to 9, and dot segment 6
1 to 4, and can take a plurality of display formats.

In other words, when displaying 3-digit surface potential (displayed in 5V units in this case), segment 61-2
is used as the hundreds digit, segment 61-3 is used as the + digit, and segment 61-4 is used as the ones digit. If the segment 61-4 is lit, it is assumed that 5 is being displayed. Therefore, when displaying 215 (V), segment 61-
2 and 61-3 to display 21, and further light up segment 61-4.

Switches SW1 to SW8 connected to the CPU 41 are control command switches, and switch SW1 commands the self-diagnosis mode when in the ON state (however, the contents of the self-diagnosis are determined by the combination of switches SW6 to SW8), and when in the OFF state, the switch SW1 commands the self-diagnosis mode. When a strobe signal is applied to the signal line 43 and a data signal is applied to the signal line 42, control is commanded according to the data signal, and when the strobe signal is in the OFF state and the strobe signal is not applied. is the switch SW6~
It executes instructions determined by the combination of SX8.

Note that even if a strobe signal and a data signal are applied while the switch SW1 is in the ON state, the self-diagnosis is executed by ignoring the strobe signal and data signal.

The switch SW2 is a switch for selecting whether to perform potential control (output control of the primary and secondary chargers), and outputs a standard value when not selected.

Switch SW3 is a switch for selecting whether or not to perform light amount control (original exposure lamp control).
If not selected, the standard value is output.

The switch SW4 is a switch for selecting whether or not to perform developing bias control, and when not selected, outputs a standard value.

Switch SW5 is in self-diagnosis mode, display circuit,
This selects the time interval of data output to the D/A converter.

Switches SW6 to SW8 are switches that represent a numerical value consisting of 3 bits, and for example, all switches
By setting it to OFF, it represents (000) and the value is 0.
By turning on all the switches, (111) is expressed and the numerical value 7 is expressed.

FIG. 3 is a flowchart showing an outline of the operation of the CPU 41 in FIG.
It initializes the RAM, I/O ports, and the LEDs. When this initialization is completed, it is determined whether it is in self-diagnosis mode (switch SW1 is ON)
It is determined in step S3 whether or not the mode is set, and if it is determined that the self-diagnosis mode is set (switch SW1 is ON), a self-diagnosis is performed in step S4. If it is determined that it is not in the self-diagnosis mode, step S5 checks whether there is a control signal (signal line 4).
(Whether or not the strobe signal is being sent by 3)
Determine.

As a result, if there is a control signal, the control mode is executed in step S6, and if there is no control signal, various data are output in step 7.

To explain this self-diagnosis program in more detail with reference to FIG. 4, in step S8, interrupts are disabled and the surface potential sensor 56 is made inoperable, and then in step S9, it is determined whether the values obtained by switches SW6 to SW8 are 7 or not. If the value is 7, the common channel CHC is connected to the channel CH1 by the multiplexer 59, and the potential is displayed by the display 61 in the second display mode. The setting value of this potential is
Since it is OV, if it is not in OV, A/D
A variable resistor (not shown) in the converter 58 is adjusted so that the potential is within the set range.

If the numerical value is not 7, the process advances to the next step S11 and it is determined whether the numerical value is 6 or not. 6 is a second display mode in which the common channel CHC is connected to the channel CH2 by the multiplexer 59 and the measured potential is displayed by the display 61. This confirms the reference potential -E (V).

If the numerical value is not 6, the process advances to the next step S13 and it is determined whether the switch SW5 is ON.

SW5 is a switch for determining the rate of level change during checking in subsequent steps S17, S19, S21, and S23. By turning on switch SW5, the software counter DACNT is added by 4 at a constant speed to increase the speed. By changing the level at the speed and turning it off, the counter
The level is changed at a slow speed by adding 1 to DACNT at the constant speed.

By causing the level to change at such a slow speed, it becomes possible to clearly identify the lighting state of the segments of the display device, so that failures in the segments of the display device can be easily discovered.

In the next step S16, the switch SW6
~Determine whether the value by SW8 is 5 or not,
When it is 5, the primary high voltage is checked.

This check is performed by applying the output of the counter DACNT as a parameter PC to the D/A converter 50, which sequentially increases the numerical value, and when it reaches a certain value, returns to the initial value and repeats the operation of sequentially increasing the numerical value again.
This is to check whether each circuit is operating normally by measuring the converted analog value, the output of the D/A converter 50, and the input or output of the high voltage primary transformer 45 with a measuring instrument. be. For example, if the output of the D/A converter 50 is normally output when the above check is performed, but it is confirmed that the input signal of the high voltage primary transformer is abnormal, the faulty location may be the D/A converter 50. It can be easily determined that the circuit is located between the A converter 50 and the high voltage primary transformer input terminal. In this embodiment, it is possible to easily determine which part of the circuit has a failure by simply switching a switch, which reduces the time required for board checks at the factory and for service in the market. Furthermore, since no special circuit is required, it can be realized at a very low cost. At this time, in order to confirm the contents of the check, the characters "C1" are displayed on segment 61-2 (U-LED) and segment 61-3 (M-LED). If the numerical value is not 5, proceed to the next step S18 to determine whether the numerical value is 4 or not, and if it is 4, sequentially change the numerical values input to the D/A converter 51 in the same manner as in step S17 above. Therefore, the output of DACNT is applied as the parameter SC. Similarly, segment 61-
2. The characters "C2" are displayed in segment 61-3 to confirm the contents of the check.

If the numerical value is not 4, the process proceeds to the next step S20 and it is determined whether the numerical value is 3 or not.

When the numerical value is 3, the output of DACNT is applied as the parameter HL in order to sequentially change the input numerical value to the D/A converter 52 in the same manner as in step S17. At this time, similarly, segment 61-
2. In order to display the contents of the check in segment 61-3, the characters "HC" are displayed.

If the numerical value is not 3, the process proceeds to the next step S22, where it is determined whether the numerical value is 2 or not. Apply the output as parameter DB and then
The data of the upper 4 bits of DACNT is displayed on the display 61.

At this time, the display 61 shows -00., -11., -22.,...
The operation of the display 61 and display circuit driver 60 is checked, and at the same time, the D/
Changes in the output of the A converter 53 are also displayed.

And when the number is not 2, that is, the switch
If the numerical values in SW6 to SW8 are 0 or 1, the process advances to step S24 and the failure mode is displayed.

This failure mode is displayed on the display 61-2, depending on the result of the potential diagnosis performed in step S4.
The characters “OH”, “EE”, “EA” are displayed on the display 61-3.
It shows the operator whether the device is normal or, if there is an abnormality, what kind of failure it is. This makes it easier to discover failures.

Next, control step S6 in FIG. 3 will be explained in more detail with reference to FIG.

When the switch SW1 is OFF and the strobe signal is output on the signal line 43, step S6 is executed, but the content of the execution is based on the 4-bit code signal output on the signal line 42. It is determined by the numerical value 0 to 15 represented by . Therefore, first, in step S30, it is determined whether or not the data signal on the signal line 42 is a numerical value of 15. If this data signal is 15, the mode is set to 0.7, that is, the reduction copy magnification is 0.7 in step S31. Change the software flag to output high-voltage primary output and high-voltage secondary output corresponding to Similarly, when the data signal is 14 in step S32, the software flag is changed in step S33 so as to output a high voltage primary output and a high voltage secondary output corresponding to mode 1, that is, same-size copy. Corresponding to the software flags changed in steps S31 and S33, high voltage primary and high voltage secondary are output in step S7 (FIG. 3).

Thereafter, control is performed in the same manner according to the flowchart shown in FIG.
Let me explain in more detail, step S34.
In this case, if the data signal has a value of 13, the secondary weak software flag is cleared in step S35. When the secondary weak software flag is cleared, the high voltage primary output and high voltage secondary output are output during normal copying. When the secondary weak software flag is set, the high voltage primary output is set to 0, the high voltage secondary output is decreased, and the residual charge on the drum 21 is removed when the copying rotation stops. This is also step S7,
The secondary weak software flag is determined and secondary weak output is performed. In step S36, if the data signal is 12, in step S37,
Set the secondary weak software flag.

Next, in step S38, if the data signal is 11, Vw is measured and the measured value is stored in step S39. Vw refers to the potential of a latent image created on the drum 11 by a test chart placed on the document table.
The measurement signal (data signal value 11) is sent from the master CPU 40 to the slave CPU 41, where it is sampled and held (stored).

VW is used in the market for image adjustment by service personnel and for factory adjustments.

Vw is displayed on the display 61 when step S53 (FIG. 6), which will be described later, is executed.

When the data signal line has a value of 10 in step S40, the surface potential V _L2 of the drum 11 for determining the developing bias is measured by the sensor 56 and stored in step S41. The developing bias calculated based on V _L2 is also stored. Similar to Vw, V _L2 is displayed on the display 61 when step S55, which will be described later, is executed. The stored developing bias is output to the D/A converter 53 in step S7.

In step S42, when the data signal is 9, in step S43, the surface potential V _L1 of the drum 11 for measuring the light amount of the document exposure lamp is detected by the sensor 5.
6 and stored. The amount of light from the document exposure lamp calculated based on V _L1 is also stored. Similarly, in step S57, VL1 is displayed, and in step S7, the calculated value of the original exposure lamp light amount is displayed on the D/A converter 5.
Output to 2.

Steps S45 and S46 control the high voltage primary output and the high voltage secondary output, and perform calculations to converge the bright area potential V _sL and dark area potential V _D of the drum 11 to target values. That is, in step S44, the signal data becomes 8.
Step S45 is executed when
Execute step S46. By executing steps S45 and S46 in this order, the surface potentials V _sL and V _D of the drum 11 for determining the high voltage primary output and the high voltage secondary output are measured by the sensor 56 and stored. Based on V _sL and V _D , high voltage primary output and high voltage 2
The next output is calculated and stored. Similarly, V _sL ,
V _D is displayed on the display 6 when steps S59 and 61 are executed.
1, and in step S7, the stored high voltage primary output and high voltage secondary output are output to the D/A converter 5.
It is output to 0,51. After the process described above is completed, the process proceeds to step S47, and it is confirmed that the strobe signal is not led out onto the signal line 42.

This is done to prevent the above process from being executed multiple times during one pulse of the strobe signal.

Next, control step S7 in FIG. 3 will be explained in more detail with reference to FIG.

When switch SW1 is OFF and there is no strobe signal, step S7 is executed, but the content to be executed differs depending on which value from 0 to 7 corresponds to the combination of switches SW6 to SW8. First, it is determined in step S50 whether the numerical value is 7 or not, and when it is determined that it is 7, step S51 is executed. That is,
A sensor drive signal is applied from the CPU 41 to the signal line 62, and the surface potential of the drum 11 is measured by the sensor 56. At the same time, the multiplexer 59 connects the channels CHO and CHC, and the read surface potential is immediately displayed on the display 61. (first display mode).

In the following, control is performed in the same manner according to the flowchart shown in FIG.
S53, S55, S57, S59, S61, S63, and S64 will be explained in more detail. Steps S50, S52,
S54, S56, S58, S60, and S62 determine the numerical values 0 to 7 based on the combination of SW6 to SW8, and perform the corresponding processing steps S51, S53, S55, S57, S59, S61, S63,
Select execution of S64.

Step S51 is executed when the switch value is 7, operates the potential sensor 56, switches the multiplexer 59 to CHO, measures the surface potential of the drum 11, and immediately displays it on the display 61.
If you set the switch to number 7, the constant step
In order to execute S51, it is possible to read the surface potential of the drum 11, which changes moment by moment, from the display 61, and thereby it is possible to easily know whether there is any abnormality in the electrometer (sensor 56). For example, if the displayed potential does not change at all or is not the expected value, it can be determined that there is an abnormality in the electrometer.

Steps S53, S55, S57, S59, and S61 are the measured potentials sampled and held as described above (Fig. 5).
Displays VwVL2, VL1, VSL, and VD. Since the stored value is updated every time a measurement is made, the value of each surface potential measured last can be easily known from the display 61. Therefore, each process unit 4
It is possible to judge from each surface potential whether control is being performed normally or not, and if not, the cause and location of the abnormality.

Step S63 displays on the display 61 PCO7, SCO7, that is, the values obtained by multiplying the high voltage primary output and high voltage secondary output calculation values stored in the memories M1 and M2 in step S46 by 0.7 using the ALU. However, when displaying, allowable values for PCO7 and SCO7 are divided in advance into 10 areas from 0 to 9, and one-digit numbers 0 to 9 are used to indicate which area the value corresponds to. It is expressed as In other words, PCO7 is indicated by the display 61-2.
is expressed as a numerical value from 0 to 9, and the display 61-
By expressing SCO7 as a numerical value from 0 to 9 using 3, it becomes possible to roughly know PCO7 and SCO7 at the same time.

In step S64, VC=VD-VSL is calculated and displayed on the display 61. By looking at VC, that is, the contrast potential, it has become possible to know whether the high voltage primary output and high voltage secondary output are being controlled normally.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a copying apparatus to which the present invention is applied;
FIG. 2 is a control circuit diagram of the copying apparatus, and FIGS. 3 to 6 are flowcharts for explaining the operation of the control circuit shown in FIG. Here, 11 is a drum, 22 is a primary charger, 23
is a static eliminator, 40 and 41 are CPUs, 45 is a high voltage primary transformer, 46 is a high voltage secondary transformer, and 47 is a high voltage secondary transformer.
CVR, 48 is developing bias transformer, 50,5
1, 52, 53 are digital analog converters,
58 is an analog-to-digital converter, 59 is a multiplexer, and 61 is a display.

Claims (1)

[Scope of Claims] Process means for forming an image on a recording medium, detection means for detecting the surface potential of the recording medium, and A/D conversion means for converting a detection signal from the detection means into a digital signal. and, in order to optimize image forming conditions related to image density, when controlling the process means prior to forming an image on the recording medium, the detection means controls the process means. The detected detection signal is converted into a digital signal by the A/D conversion means, a predetermined calculation is performed on the output, and a control signal for controlling the process means is sent to the processing means according to the calculation result. A digital computer for outputting data, a display means for displaying numerical values, a reference potential generation means for generating a reference potential, and a detection means for controlling the above-mentioned process means for optimizing image forming conditions when the control of the above-mentioned process means is not being executed. a first display mode in which the detected surface potential is input to the A/D conversion means while detecting the surface potential of the recording medium, and the output of the A/D conversion means is displayed on the display means; and display switching means for switching between a second display mode in which the reference potential generated by the reference potential generation means is inputted to the A/D conversion means and the output of the A/D conversion means is displayed on the display means. An image processing apparatus, wherein the digital computer disables the detection means in the second display mode.