JPS63177158A - Image forming device - Google Patents

Abstract

PURPOSE:To form an image with good gradations regardless of variation in environmental condition, the secular change of a recording body, etc., by varying conversion information according to detected image formation conditions. CONSTITUTION:This device is equipped with a converting means which converts input digital image data according to the conversion information, output means which select and output the converted image data as an image signal, and an optical means which forms an image based upon the image signal on the recording body, and image formation parameters are varied to monitor the image formation conditions. Then a monitor means monitors the image formation conditions as many as the image formation parameters, and a control means varies the conversion information according to the image formation conditions detected corresponding to the selected image formation parameters. Thus, the relation between the potential on a photosensitive body and image data is made constant and developer characteristics are considered, so the stable image is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus that reproduces image data.

[Conventional technology]

The sensitivity of a photoreceptor changes over time or due to changes in environmental conditions such as temperature and humidity. In particular, in the method of modulating one pixel with a predetermined area ratio, there is a lag between the point at which the laser emits light and the time until it stops emitting light, so the area ratio at which the laser emits light and the area ratio at which it stops emitting must be determined and controlled in advance. Ta. The point Voo where the photoreceptor potential at that time starts emitting light
Conventionally, when the stopping point is VFF, there has been a phenomenon in which the potential curve changes over time as shown in FIG.

To explain from Figure 13, the vertical axis is the surface potential, the horizontal axis is the grid voltage VG for controlling the potential, and the curve of VOO of the surface potential changes from A to B and the curve of VFF changes from C to D due to changes over time. The same Vc= (Voo
-VFF) = 420V, the grid voltage should be set to 7
It is necessary to change the voltage from 00V to 100OV, but the high voltage unit has an error in control (it was difficult to vary from 200V to 100OV).

On the other hand, the developing capacity of the developing device varies depending on the environment, and in particular, the image density changes depending on the humidity, making it impossible to obtain an image with an appropriate density.

〔the purpose〕

The present invention has been made in view of the above points, and an object of the present invention is to provide an image forming apparatus capable of doing so.

〔Example〕

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

[Description of the block diagram of the color copying machine (FIG. 1)] FIG. 1 is a block diagram of the color copying machine of this embodiment.

1 is a synchronization signal processing unit which generates various timing signals in synchronization with the horizontal synchronization signal 1 22 output from the gradation control circuit 21 based on the signal from the BD (beam detector) detector 20 of the printer unit 200. Create. Reference numeral 2 denotes a close-contact type CCD sensor block, which reads a document and converts an image signal into an electric signal and outputs it in response to a horizontal synchronization signal (RH3YNC) generated by a synchronization signal processing section 1 and a drive signal 4. 3 is a signal processing section that performs waveform shaping processing to prevent high frequency components of the electrical signal 5 from attenuating.

Reference numeral 6 denotes an image processing block, in which the image signal from the signal processing section 3 is first input to an analog processing section 7.

In the analog processing section 7, the contact type CCD sensor block 2
Because the configuration is such that cyan (C), green (G), and yellow (Y) signals are sequentially output for each pixel, the signals are first separated into C, G, and Y colors. Next, printer section 2
Each developer of 00 is yellow (Y) and magenta (M).

Since it supports cyan (C), the image signal is first converted into red (R), green (G), and blue (B) signals.

This is performed by arithmetic processing according to the formulas CG=B and Y-G=R. Furthermore, since the output voltage of these signals separated into R, G, and B changes linearly with respect to the concentration, they are converted into an 8-bit concentration signal by an A/D converter. The above processing is executed by the analog processing section 7.

The image signals for each color digitized by the analog processing section 7 are divided into 5 channels, and the video signals of each channel are not synchronized, so the link memory 8 converts them into one image data. be synthesized. The image data synthesized by the connection memory 8 and converted into YMC signals is sent to an image processing unit (IPU) in synchronization for each color.
) sent to 9. The IPU 9 performs shading processing to correct light distribution, masking processing to correct color tone, and the like. Further, a desired color signal is selected by the control unit 10 of the reader unit 100, and is transmitted to the printer unit 2 from the IPU 9 through the 8-bit image data 11 that has undergone predetermined color conversion processing.
00.

In addition to the one-sided image signal, the control unit 10 drives a motor driver 13 for manipulating the original to control the rotation of the motor 12. In addition, a CV that controls lighting of the exposure lamp 14
It also controls the R15, the copy key, and the operating section 16 for performing other operations.

Here, to make the text sharp and the photo to have gradation,
Although not shown, it has a switching mode SW, and the control unit IO takes in the information from the operation unit 16 and sends it to the printer.

On the other hand, the control section of the printer controls a selector of a binarization circuit, which will be described later, using a signal from the CPU 25-1.

The image data 11 output from the league section 100 is input to the gradation control circuit 21 of the printer section 200.

Since the speeds of the image clock of the league section 100 and the image clock of the printer section 200 are different, the gradation control circuit 21 has a function of synchronizing them and a function of making the image data correspond to the color reproduction density of the printer section 200. have.

Output data from the gradation control circuit 21 is input to a laser driver 22, which drives a laser 23 to form an image.

A control section 25 of the printer section, which communicates with the league section 100 via the communication control line 24, controls each control element of the printer section 200. 26 is a potential sensor for detecting the charge charged on the photoreceptor 29; 27 is a potential sensor 2;
This is a potential measuring unit that converts the output from 6 into a digital signal and inputs it to the control section 25.

The potential data input to the control section 25 is
It is read by r'U25-1 and used for control.

On the other hand, a signal from the sensor 28 for detecting an image leading edge signal (ITOP) is input to the control section 25 and used for control. Further, in order to correct the development characteristics, a humidity sensor 98 and a temperature sensor 99 are inputted through the A/D conversion section 25-3 of the control section 25. As shown in FIG. 17, the humidity sensor 98 in this embodiment has characteristics that change depending on temperature, with resistance on the vertical axis and absolute humidity on the horizontal axis. Therefore, the ratio of saturation amount at each temperature and relative humidity △H
is expressed as ΔH=f (T, H) T=humidity temperature H=humidity sensor value. Usually, the f function is expressed by a cubic equation.

These T and H are the temperature sensor 99 and humidity sensor 98, respectively.
The control section 25-3 converts the humidity into A/D and calculates the relative humidity.

Control, which will be described later, is performed in accordance with the determined relative humidity.

FIG. 8 is a block diagram of a copying apparatus using the contact type color CCD sensor of this embodiment.

The copying apparatus 80 includes a league section 100 and a printer section 200. Reference numeral 83 denotes a document scanning unit that reads the image of the document 84 on the document table (moves and scans in the direction of arrow A, and at the same time turns on the exposure lamp 85 in the document scanning unit 83.The light reflected from the document is The light is guided by a focusing rod lens array 86 and focused on a contact type color CD sensor 87.The contact type color CCD sensor 87 has a chip of 1024 pixels, with each pixel being 62.5 μm (1/16 mm). Five chips are arranged in a staggered pattern, and each pixel is divided into three parts of 15°5 μm x 62.5 μm, each with C and G pixels.

A Y color filter is attached.

The optical image focused on the contact type color 〇〇D sensor 87 is
Each color is converted into an electrical signal. These electrical signals are subjected to predetermined processing, which will be described later, by a processing block 88. The color separated image electrical signals formed by image processing block 88 are sent to printer 200 for printing.

The color image data from the league unit 100 is subjected to PWM processing, etc., and finally drives a laser.

The laser beam modulated in accordance with the image data is scanned at high speed by a polygon mirror 89 that rotates at high speed, and then
The light is reflected onto the surface of the photosensitive drum 91 to expose dots corresponding to the image. One horizontal scan of the laser beam corresponds to l horizontal scans of the image, and in this embodiment, the width is 1/16 mm. On the other hand, since the photosensitive drum 91 is rotating at a constant speed in the direction of the arrow, a planar image is sequentially exposed by the above-described laser beam scanning in the main scanning direction and by constant rotation of the photosensitive drum 91 in the sub-scanning direction. Prior to exposure, the photosensitive drum 91 is uniformly charged by a charger 97, and a latent image is formed by exposing the charged photosensitive member to light. A developing unit 92 corresponding to a predetermined color for a latent image based on a predetermined color signal.
~95 is visualized.

For example, considering the first original exposure scan in a color reader, a dot image of the yellow component of the original is first exposed onto the photosensitive drum 91 and developed by the yellow developer 92 .

Next, this yellow toner image is transferred onto a sheet of paper wound on a transfer drum 96 at a contact point between the photosensitive drum 91 and the transfer drum 96 by a transfer charger 98 . The same process is M (magenta),
By repeating C (cyan) and Bk (black) images and superimposing each image on the paper, a color image using four color toners is formed.

At this time, since the characteristics of the developer in each developing device differ depending on the humidity condition, the image density with respect to humidity when printing under the same image forming conditions is as shown in FIG. Further, the image density with respect to the surface potential of the photosensitive drum with humidity as a parameter is as shown in Fig. 1θ.

Therefore, the required target potential is V C2 for relative humidity of 80%, 50%, and 20% if Do is fixed.

Different from Vc+ and Vco. (In this example, Vc=150
V.

(VCI=240V, VCO=300V) On the other hand, in the potential characteristics of the photoreceptor shown in FIG. 13, when the voltage is 250V or more, the grid voltage becomes high and the control accuracy is not achieved, so it is necessary to change the laser power. Therefore, in this embodiment, control is performed so that the laser power is switched when the humidity is 50% or less.

[Description of gradation control circuit (FIGS. 2 and 3)] FIG. 2 is a block diagram of the gradation control circuit 21. As shown in FIG.

The 8-bit image data 11 output from the IPU 9 of the reader section 100 is processed by the synchronization signal RH from the synchronization signal processing section l.
The signal is input to the buffer memory 30 in synchronization with S Y N C and the image clock RCLK. The image data stored in the buffer memory 30 is
It is read out from the buffer memory in synchronization with the SYNC and CLK signals 32. As a result, the reader section 100 and the printer section 200 are out of synchronization and speed conversion is performed, and the results are output to the selector 33.

When the selection signal 34 from the CPU 25-1 of the control unit 25 selects the A input of the selector 33, the image data is input to the address of the look-up table RAM (LUTRAM) 38. At this time, when the CPU 25-1 reads out the LUTRAM 38 using the control signal 36, the LUT
The RAM 38 outputs data corresponding to address input. The output data is output to the selector 39 and input to the next selector 40 in response to the aforementioned selection signal 34.

When the selection signal 42 of the selector 40 selects eight-person power, it is output to the D/A converter 41 and converted into an analog signal.

The image signal 41-1 converted to analog is sent to the binarization circuit 4.
It is binarized by 4. A specific example of the binarization circuit 44 is shown below.
It is shown in Figure 6. A triangular wave is generated by the triangular wave generating circuit 44-1 based on the CLK signal 51 output from the synchronization control section 31, and the gain and offset level are set to 44-3.
．． The signal is adjusted by the volume indicated by 44-5, and compared with the analog image signal 44-1 by a comparator 44-6 to perform pulse width modulation (PWM modulation) and input to the selector 44-25.

The relationship between the output pulse width and the amount of laser emitted light has the characteristics shown in FIG. 14-2. Image data OOH
~FFF (hexadecimal) is used to reduce the O of the image data in order to use the linear part of this characteristic curve as widely as possible.
Using a device that can measure light energy in the optical path, set the gain as described above so that OH is the power when the curve starts to become linear, and FFH of the image data is the power when the curve is just before it deviates from linear. Manually adjust the offset volume.

However, when switching the laser power, which will be described later, the laser starts emitting light after exceeding a predetermined threshold current, so even if the same pulse is applied, the laser current will differ, as shown in Figure 14-1. The amount of laser light will differ. Therefore, when switching the laser power, the relationship between the pulse width given to the laser driver 22 and the amount of light is as shown by curves ■ and curve ■ shown in Figure 14-2, where the linear region described above changes (
Ru.

Here, the curve (2) is when the laser power is large, and the curve (2) is when the laser power is small.

Therefore, in order to obtain the same image density for the same image data even if the laser light intensity is changed, it is necessary to change the pulse width as the laser light intensity is switched. This is achieved by having a binarization circuit.

Although this embodiment has a plurality of binarization circuits as shown in FIG. 16, it is also possible to have a plurality of circuits for controlling the gain and offset level and to switch between them.

Furthermore, a CLK signal 51 output from the synchronization control section 31
Similarly, the 3CLK signal 52 having different synchronization from the above has a plurality of binarization circuits in accordance with switching of the laser power. The selector 44-25 switches and outputs a plurality of pulse width modulated binary image signals according to a signal from the CPU 25-1.

The image signal pulse width modulated by the binarization circuit 44 is sent to an OR circuit 45. The signal is output to the laser driver 22 through the AND circuit 46.

FIG. 15 shows details of the laser driver 22. here,
Analog 5 according to information determined by control unit 25
W22-7 operates to change the constant current value supplied to the laser 23. This will be further explained below.

A signal sent from the AND circuit 46 of the gradation control circuit 21 is inputted to one transistor 22-2 of the differential circuit via the buffer 22-1 inside the laser driver 22. The other transistor 22-3 is for driving the laser 23. On the other hand, there is a transistor 22-4 that supplies a constant current between the transistors. The signal supplied from the constant voltage source 22-6 is supplied to the operational amplifier 22-5 on the + side, and the voltage applied to the resistor R5 for observing the current of the transistor 22-4 is supplied on one side, causing a predetermined current to flow. A voltage for this purpose is supplied to transistor 22-4.

On the other hand, the analog SW 22-7 is operated by the buffer 22-8 that receives the I10 signal from the control unit 25.
As a result, the voltage supplied to the + side of the operational amplifier 22-5 changes, the constant current value changes, and the current supplied to the laser 23 changes.

The analog SW was provided because when the voltage at the 0 point is switched, if there is an oven condition even momentarily, the output of the operational amplifier 10 input will rise and the current limit will not be applied (so that the semiconductor laser This is to prevent destruction.

Next, the blanking signal 48 from the synchronization control section 31 is
This is a signal for turning on the laser 23 at the BD detection section in order to detect a BD. Also, the signal 49 is the CPU 25-1
This is an inhibit signal for the laser 23 outputted from the laser 23, and is used to prevent the life of the laser 23 from deteriorating.

50 is a pattern generator that outputs a predetermined pattern for checking the image signal. The pattern generator 50 includes:
A transfer drum synchronization signal ITOP, a horizontal synchronization signal H3YNC of the printer section 200, and a control signal from the CPU 25-1 are input. When outputting a pattern signal, the CPU 25-1 switches the selection signal 42 of the selector 40 to the B input, and inputs the data from the pattern generator 50 to D.
/A converter 41 to check the image signal.

Based on the reference clock of the crystal oscillator, the synchronization control unit 31
CLK51 and 3CLK as clocks for triangular wave generation
52 is output according to instructions from the CPU 25-1, and the BD double signal from the BD detector 20 is inputted to output the blanking signal 48 or the horizontal synchronizing signal H3Y of the printer section 200.
It outputs NC and image clock CLK. The binarization circuit 44 outputs CLK51. based on the input clock. Alternatively, a binary signal 47 synchronized with 3CLK52 is output.

FIG. 3 is a timing chart showing the timing of these BD double signal blanking signals 48, etc.

A clock with a period twice or more that of the image clock is input from the crystal oscillator to the synchronization control unit 31, and synchronized with the BD double signal clock) (SYNC, CLK, etc.) are output.The blanking signal 48 is the BD double signal clock. It is created by a counter that measures a time shorter than the BD signal cycle and is reset at the falling edge of the signal.

[Explanation of the operation of the league section (Fig. 4)] Fig. 4 shows the league section 10 (1) control section 10 (7) CPUI
This is an operation flowchart of O-1, and this program is built in ROM10-2.

When league division I00 is powered on, first step S
Execute the initial display routine with l.

This includes checking each I10, initializing RAM10-3, and moving the document scanning start point. In step S2, it is checked whether the league section 100 is connected to the printer section 200.

In step S3, it is checked whether the print switch of the operation unit 16 has been pressed. When the switch is pressed, the process advances to step S4, and a print-on command is output to the printer section 200. Step S5 waits for the input of the IPOP signal from the printer unit 200, and when the ITOP signal is input, step S5
6, the image is scanned in the designated color mode and a video signal is output to the printer section 200.

[Explanation of operation of printer unit (Fig. 5)] Fig. 5 is a flowchart of a processing program by the control unit 25 of the printer unit 200, and this program is stored in the ROM 25.
-2.

When the printer unit 200 is powered on, step SIO
The initial routine is executed. Here each I10
Performs initial operations such as checking, initializing the RAM, and removing the drum potential from the machine body. Step Sl
In step 1, the connection with the league unit 100 is checked, and if the connection is confirmed, the process proceeds to step 512, where it is checked whether the heater of the fixing unit has reached a predetermined temperature (warm-up has been completed). When the warm-up is completed, the process advances to step S13 to see if there is a print instruction from the league club 100. When the print instruction is input, step S14 (514
-1 to 514-4) execute the I'GON processing described later.

The r'GON processing is performed in accordance with the laser power and the clock used for triangular wave generation.

In step S15, as will be described later, based on the result of step S14, the L
Calculate the write data of UTRAM38 and step S1
6, it is written to LUTRAM38. This selects the B input of the selector 33 by the selection signal 34, while the selector 39
The data bus 36 of the CPU 25-1 is connected to the LUTRA
Connected to the data input of M38.

Here, the CPU 25-1 sends the LUTRA to the address bus 35.
The address of M38 is outputted as write data to the data bus 37, and a write pulse is manually inputted using the control signal 36.
Write to UTRAM38.

In step S17, it is checked whether writing to the LUTRAM 38 has been completed, and when it has been completed, in step 31B, the league section 1
001. :Outputs ITOP signal. As a result, control shifts from step S5 to step S6 in the reader unit 100 program flowchart of FIG. 4 described above. In step S19, the specified color mode is performed.

Needless to say, at this time, the LUT is performed by switching the selector for each color. Next, step S19. When a printing operation is performed in S20 to form a one-color image and the color mode ends, the process returns to step Sll again.

(Explanation of PGON processing (Fig. 6, Fig. 7)] The PGON processing in steps 514-1 to 5144 is the same except for the laser power used and the clock used for triangular wave generation. A summary will be explained with reference to FIG.

FIG. 6 is a flow chart of the PGON process in step S14 of FIG. 5, that is, the process of driving the pattern generator 50 to output a predetermined pattern and reading the surface potential of the photosensitive drum.

In step S30, the B input of the selector 40 is selected by the selection signal 42 in order to input the data from the pattern generator 50 to the D/A converter 41. In step S31,
The data output by the pattern generator 50, e.g.
00”, the photoreceptor 29 is
The potential occurring above is input through the potential measuring unit 27. It is assumed that the binarization circuit 44 is set in advance so that the comparator 43 generates a limit pulse at which the laser emits light when the input to the D/A converter 41 is 0''.

As a result, the photoreceptor 29 is irradiated with uniform light by the laser driver 22 and the laser 23 .

Furthermore, when the pattern generator 50 outputs the data "FF" in hexadecimal in step S31, the laser 23 is set to a binary value so that the laser 23 emits light at a cycle shorter than the cycle of the triangular wave, that is, so that the dots can be accurately reproduced. The conversion circuit 44 is set, and the potential corresponding to the data "FF" is read in the same manner as described above.

In step S32, the target surface potential of Vc for giving a predetermined concentration is determined according to the detected humidity, and the read potentials VOO and VFF corresponding to the data "00" and "FF" from the pattern generator 50 are determined. Find the difference and see if the difference is a predetermined value. If it is not the predetermined value, step S33
The process proceeds to step S31, where the -th order high voltage of 97 in FIG. 8 is changed, and the process returns to step S31 to perform a check.

Here, a command is sent to the laser drive circuit to reduce the laser power if the differential voltage Vc between VOO and VFF is below a predetermined value, and to increase the laser power if it is above a predetermined value.

When the difference reaches a predetermined value in step S32, the process proceeds to step S34, and the pattern generator 50 is turned on. As a result, the pattern generator 50 synchronizes with ITOP and generates H3YNC.
It starts operating as an m-ary counter, and sequentially outputs data obtained by dividing data "OO" to "FF" into a predetermined number of stages m. This data is input to the D/A converter 41 through the selector 40 and becomes an analog signal to the laser 23.
to drive. Step S35. In S36, the potential of the photoreceptor 29 that is generated by this and changes in m stages is read and sequentially stored in correspondence with the output data of the pattern generator 50 (.

Note that in this embodiment, m=16.

FIG. 7 is a diagram showing the relationship between the input data of the D/A converter 41 and the voltage value from the potential measuring unit 27.

The photoreceptor 29 is negatively charged, and when irradiated with laser light, the potential increases. Correspondingly, negatively charged toner of each color adheres. In the figure, VDD indicates the charging level when the laser does not emit any light, and VL indicates the charging level when the laser does not emit any light.

In this embodiment, PGON processing is always performed for all laser powers and triangular wave generation clocks before the copy sequence, but the PGON processing is performed at certain time intervals or for a predetermined number of copy operations using a timer. It is also possible to have the process performed every time the process is performed. Alternatively, the process may be performed only for the selected laser power and triangular wave generation clock.

Furthermore, a dedicated sequence for only PGON processing may be provided, measured values may be stored, and the LUT may be created using the data stored during the normal copy sequence.

[Explanation of step 21 LUT creation process (Fig. 12)] Fig. 12 is a diagram showing the output image density for the human input image signal, and the first quadrant shows the relationship between the output density and the input level e.
The inlay shows the relationship of the conversion level E to the input level e (LU
T) The third quadrant is the relationship between the conversion level E and the measured potential V by the potential sensor (EV right curve) The fourth quadrant is the relationship between the measured potential V and the output density (VD
It is a right curve, and the measured potential V and output density here are V = (actual value measured by potential sensor - VFF) / (Vo
o-VFF) D-(1 degree/maximum concentration) x “FF” VOO; Actual value VF measured by potential sensor when outputting “00”
F: Actual value measured by a potential sensor when outputting “FF”.

Here, a plurality of types of curves are prepared in advance according to the developer and laser power used in the VD right curve and the clocks (CLK signal 51, 3LK signal 52) used to generate the triangular wave of the binarization circuit 44 in FIG. It is set in the ROM 25-2 and selected from there for use.

In addition, since the EV right curve has almost linear characteristics, during PG operation during potential measurement (step 534 in Figure 6), a table corresponding to the selected VD right curve (VD right curve y-axis and y-axis are reversed) is used. table) in LUTRAM3
8, and measurements are performed using the data converted by this LUTRAM in advance. In addition, LUTR
The data to be written into the AM38 may be set in advance in the ROM and used.

To create the LUT, in order to make the output density linear with respect to the input level e, the conversion level when the PG output level e1 is Ei, the measured potential at that time is vl, and VD
Assuming that the concentration increases when the measured potential is vI from the right curve, the LUT data is created so that the conversion level when the input level e1 is Dl becomes El. In this example, PG ratio output is performed in 16 steps, so 1
Six pieces of LUT data are created, and the LUT data is completed from "OO" to "FF" by polygonal line approximation.

Note that in this embodiment, RAM is used as the lookup table.
However, it is also possible to use a ROM in which a plurality of data groups are written in advance, and select appropriate data from the data stored in the ROM based on the calculation result of the CPU.

As described above, according to this embodiment, a stable image can be obtained because the relationship between the potential on the photoreceptor and the image data is constant, and the characteristics of the developer are also taken into consideration. Further, in the case of a color image, since variations in color can be prevented, there is an effect that an image without any color change □ can always be obtained.

〔Effect of the invention〕

As described above, the present invention has the effect of stably reproducing images.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1(a) and 1(b) are block diagrams of the color copying machine of this embodiment. FIG. 2 is a block diagram of the gradation control circuit. FIG. 3 is a timing chart of each signal of the synchronous control block. FIG. 4 is an operation flowchart of the control section in the beamer section. FIG. 5 is an operation flowchart of the control section in the printer section. FIG. 6 is a flowchart of data output and potential reading processing of the pattern generator. FIG. 7 is a diagram showing the relationship between the data of the pattern generator and the potential of the photoreceptor. FIG. 8 is a sectional view of the color copying machine. FIG. 9 is a diagram showing the relationship between image density and humidity when printing under the same image forming conditions. FIG. 10 is a diagram showing the relationship between the image density and the surface potential of the photosensitive drum when printing is performed under the same image forming conditions. FIG. 11 is a diagram showing the relationship between concentration data and measurement data of the potential sensor, which is set in advance in the ROM. FIG. 12 is a diagram showing the relationship between output image density and input image signal. FIG. 13 is a diagram showing the relationship between the surface potential of the photoreceptor and the control voltage, and the change in potential over time. FIG. 14-1 is a diagram showing the relationship between laser power and light emission waveform, and FIG. 14-2 is a diagram showing the pulse width of the binary output and the amount of light emitted by the laser. FIG. 15 is a diagram showing a detailed view of the laser driver 22. FIG. 16 is a detailed diagram of the binarization circuit 44. FIG. 17 is a diagram showing the characteristics of the humidity sensor. In the diagram, 1・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・Synchronization signal processing section, 2・・・・・・・・・・・・・・・・・・・
......Contact type CCD sensor block, 3...
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
...Signal processing section, 7...
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・Analog processing section, 8・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・Connection memory, 9・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・IP
U. 10・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・Control unit, 11・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・ Image data, 16・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・Operation section, 20
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・BD detector, 21 ・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
...... Gradation control circuit, 22...
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・ Laser driver, 23・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・Laser, 25...
・・・・・・－・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・Control unit, 26・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・Potential sensor, 2
7・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・Potential measurement unit, 29・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・Photoreceptor, 30...
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・Buffer memory, 3
1 ・・・・・・・・・・・・・・・・・・・・・・・・
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...Synchronization control section, 33.39.40...
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......Selector, 38...Lookup table RAM (LUTRAM), 41...
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・・・・・・・・・・・・・・・・・・・・・・・・D/
A converter, 43・・・・・・・・・・・・・・・
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・・・・・・Comparator, 44・・・・・・・・・
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・・・・・・・・・・・・・・・Triangular wave generator, 50
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・・・・・・・・・・・・・・・・・・Pattern generator, 100 ・・・・・・・・・・・・・・・・・・
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・・・・・・・・・・・・League Club, 200・・・・・・
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......This is the printer section.

Claims (4)

[Claims] (1) A conversion means for converting input digital image data according to conversion information, an output means for selecting the converted image data and outputting it as an image signal, and an optical system for forming an image on a recording medium based on the image signal. means for monitoring the image forming conditions by changing the image forming parameters, a monitor means for monitoring the image forming conditions as many times as the number corresponding to the image forming parameters; An image forming apparatus comprising: a control means for changing the conversion information according to image forming conditions. (2) The output means outputs the converted image data to D.
/A converting means, means for generating an analog signal of a predetermined period, reference signal generating means for generating a reference signal for forming the analog signal, and an analog image signal output from the D/A converting means. 2. The image forming apparatus according to claim 1, further comprising comparison means for comparing the analog reference signal and the analog reference signal and outputting a pulse width modulated signal. (3) The reference signal generating means is capable of generating reference signals with different cycles in order to generate the analog signals with different cycles, and the image forming parameter is the cycle of the reference signal. An image forming apparatus according to claim 2, characterized in that: (4) The image forming apparatus according to claim 1, further comprising a switching means for switching the energy of the optical means, and the image forming parameter is the energy of the optical means.