JPH04256981A - Toner concentration control system for recorder - Google Patents

Abstract

PURPOSE:To improve reproducibility in the vicinity of the density 1.0 of an original by providing a control means capable of setting the target value of the concentration, thereby changing the target value of the concentration of an ADC when a developing curve is changed. CONSTITUTION:The optical density of a reference potential part (patch) is detected by an ADC senser 31, the concentration of toner is controlled by a controller 30 in accordance with a detected result. Firstly, image quality is made optimum by optimizing the light quantity of a lamp 3 and positioning the corotron of a transferring device 26 to a photosensitive material drum 20, etc. Thereafter, the patch is formed at shorter interval than a regular copying mode in a self-diagnostic mode, the target value of the ADC is calculated by reading the concentration of the patch detected by the ADC senser 31 and is set to a nonvolatile memory 32. When color toner is used, e.g. when red toner is used, the target value is corrected based on the calculated target value and the target value of other color is set, as well.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner density control method for an image recording apparatus.

0002

[Prior Art] Generally, a reference potential area (patch) is formed in a non-image area, this area is developed with toner, the image density is optically detected, and the image density is detected based on the difference between the detected toner density and the target density. Automatic density control (AD) controls the drive of the toner dispense motor to obtain the target image density.
C) is being carried out.

0003

By the way, the purpose of the ADC function is to satisfactorily control the reproducibility of the original density around 1.0. Therefore, it is preferable that the reference reflector for forming the patch originally has a density of 1.0. However, if the original density is as high as 1.0, it will put a heavy burden on the cleaner, so it cannot be made very dark.
Usually, the concentration is about 0.4. In this way, conventional ADCs have a density of 0.4 to improve the reproducibility of 1.0 originals.
Because control is performed using originals, even if the copy density is adjusted to around 0.4 as shown in Figure 14, the development curve may change as shown in the figure if, for example, the sensitivity of the photoreceptor changes. As shown in the figure, even if the target density value is the same, the density 1. that you originally wanted to adjust the density to is the same.
In the vicinity of 0, a difference D occurs as shown in the figure. It is also affected by variations in the sensitivity of ADC control, variations in sensor mounting (orientation), and the like.

The present invention is intended to solve the above-mentioned problems, and provides a recording device that can improve the reproducibility of the original density around 1.0 by changing the ADC density target value even if the development curve changes. The purpose of the present invention is to provide a toner density control method.

[0005]

[Means for Solving the Problems] The present invention develops toner by forming a reference potential area on a sensitive material, optically detects the toner density of the reference potential area, and develops the toner based on the difference from the target density value. The recording apparatus includes a control means for controlling a dispense motor, characterized in that the control means is capable of setting a density target value. In addition, the control means is capable of setting a density target value for each toner color, shortens the cycle for creating a reference potential part in the self-diagnosis mode than in the normal mode, and detects the optical density of the reference potential part to determine the density. It is characterized by automatically setting the target value.

[0006]

[Operation] The present invention makes it possible to set and change the density target value. Specifically, after adjusting the image quality to the best condition, patching is performed in self-diagnosis mode at shorter intervals than in normal copy mode. , read the patch density detected by the ADC sensor, calculate the ADC target value, and
M, and the reproducibility of the document density around 1.0 can be improved compared to the conventional method in which the target density value is fixed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the overall configuration of an image recording apparatus to which the present invention is applied. In the figure, 1 is a platen, 2 is a reference reflector, 3 is an exposure lamp, 4, 5, 6, 8, 9, 10 are reflection mirrors, 7 is a lens, 20 is a sensitive material drum, 21 is a charger, 22 is a ISIL, 23 is a sub-developing device, 25 is a main developing device, 26 is a transfer device, 27 is a toner deturbator brush, 28 is a cleaning blade, 30 is a control device, 31
is the ADC sensor, 32 is the non-volatile memory (NVM), 3
3 and 34 are toner dispense motors, 35 and 36 are drivers, 37 and 38 are high-voltage power supply circuits, 39 is a low-voltage power supply circuit, and 40 is an amplifier.

In the figure, a sensitive material 20 is charged to a predetermined potential by discharge from a charger 21 supplied with power from a high-voltage power supply circuit 38. On the other hand, the document surface on the platen 1 is scanned with an exposure lamp 3, and the reflected light is reflected by mirrors 4, 5, 6.
, the photosensitive material 2 passes through the lens 7 and the mirrors 8, 9, and 10.
The image is formed at a predetermined position of 0. As a result, an electrostatic latent image is formed on the photosensitive material 20 in accordance with the image of the original, and this electrostatic latent image is developed with toner in the sub-developing device 23 or the main developing device 25, and further developed with a transfer corotron and a detack corotron. The image is transferred and recorded onto a sheet of paper by a transfer device 26 consisting of the following.

[0009] In such an image recording device, the AD
The C sensor 31 detects the optical density of the patch, and the control device 30 controls the toner density according to the detection result. That is, the IS is supplied with power from the low-voltage power supply circuit 39 to the non-image area that has been charged to a predetermined potential by the charger 21.
The photosensitive material 20 is irradiated with light using the IL 22 to form a dark potential portion in a predetermined area, and this area is exposed to light reflected from the reference reflector 2 to form a patch. This patch is developed with toner by the developer 23 or 25, the image density thereof is optically detected by the ADC sensor 31, and the detected image density is read into the control device 30. The control device 30 previously reads the reflected light from the clean surface of the sensitive material using an ADC sensor, and calculates the ratio Radc (Vpatch/Vclean) of the amount of reflected light from the patch portion to the amount of reflected light from the clean surface.

Radc and the amount of toner per unit area (D
MA) is an inversely proportional relationship as shown in FIG. The dispense motor 33 or 34 is driven and controlled to control toner supply. The control of the dispense motor is based on the difference D between the target reflectance and the actual reflectance.
For Radc=R0-Radc, calculate the dispense motor ON time in advance by creating a table.
From this table, the dispense motor ON time for DRadc is determined and integrated. And the cumulative value is 500
This is done by driving the dispense motor to supply toner in units of 500 msec when the time exceeds msec.

In the present invention, after making image quality adjustments such as optimizing the lamp light intensity and adjusting the position of the corotron and the sensitive material drum to optimize the image quality, the self-diagnosis mode (diagnosis) is started.
Select code 20-99 to enter normal copy mode. Code 20-9 in this diagnostic mode
In the normal copy mode according to No. 9, an ADC patch is created once every 20 copies in the normal mode, whereas a patch is created once every 2 copies. Therefore, taking 20 copies will result in 10 ADCs.
A patch is formed. The patch density is read, and the average value of 6 data excluding 2 data on the upper and lower sides of the 10 data is recorded in the NVM 32 as the target value of the ADC. When color toner is used, for example, when the color toner is red, correction is made based on the calculated target value, and target values for other colors are also set. However, when using a color other than red, the target value is automatically set only for the toner of the color being used. In this way, since the density target value can be changed, even if the development curve changes, 1.
The concentration near 0 can be stabilized.

Next, the module configuration of the recording apparatus of this embodiment will be explained with reference to FIG. In this example,
A user interface (UI) 50 that performs processing such as mode selection and settings from the user, reception of start keys, etc.
, a light lens module (L) that performs image reading processing.
LM) 60, and an IOT module 70 that performs image output processing.
Between 0 and IOT70 is IOT-I60b and CMD-S
Communication is performed by each communication module of the TS 70a. Each module of the LLM60 and IOT70 is called by each monitor and performs its processing, and the processing to obtain the area coverage of the document is performed by the LLM60 and IOT70.
carried out by the ACDC module 60f of the LM60,
The calculated value is transmitted to the CM through the IOT-I module 60b.
It is transmitted to the D-STS communication module 70a, and the IOT7
The dispense time is accumulated in the dispense buffer by the toner module 70e of 0. Also, A
Calculation of dispense time by DC check or calculation of correction coefficient is performed by ADC module 70 of IOT70.
This is done by f. Also, LLM60 is ISIL, D
It is connected to each remote such as ADF through a hotline, and the IOT 70 is connected to each remote such as DDM and HCF through a hotline. Also, LLM60 and IOT
70 has a diagnostic module as other modules 60i and 70g, for example, if you set the diagnostic mode on the UI 50 and input 20-99, LLM
In 69, the UI-I 60a or the diagnosis module sets the diagnosis ADC flag, the communication is transmitted to the IOT 70, the CMD-STS 70a or the diagnosis module similarly sets the diagnosis ADC flag, and ADC in the diagnosis mode becomes possible. In the copy mode, an ADC request signal is output once every two copies so that ADC can be performed efficiently.

Next, the configuration of the ADC module will be explained with reference to FIGS. 4 to 8. The ADC module is called every 10 msec by the print module and standby module, and auto gain control (A
GC) Checks whether processing is being performed or not, and if not, performs AGC. That is, AGC-
The PRL module 101 performs AD as pre-processing for AGC.
The AGC-MAIN module 102 performs AGC main processing. As shown in FIG.
- The CALL module 121 performs AGC read request flag setting processing, and each module 115 to 111
9 reads the Vclean value during AGC, Vou
t calculation processing, gain output calculation processing, AGC post-processing, etc., and also performs AGC-FAIL-CHK module 1.
At step 20, processing at the time of AGC failure is performed. When printing starts, the VCLN-MAIN module 103 and each module 104 to 108 in FIG. 4 perform read processing for the clean side of the sensitive material drum, Vclean average calculation processing, etc. Performs fail processing in ADC.

[0014] Also, the ADC-CTRL-MAIN in FIG.
The module 111 performs ADC main processing, and as shown in FIG. 6, it is checked whether the currently selected developer is for black or color, and if it is for black, the modules 123 and 124 calculate the average of Vpatch. Radc is calculated, and the ADC-BLK-MAIN module 125 performs the ADC calculation.
The main processing of ADC and A is performed in module 130.
The dispense time determined by the CDC is stored in the dispense buffer, and the module 129 calculates the concentration difference. Also, Diag ADC (20-99)
is selected, the processing is performed by modules 128 to 134, a patch is generated once every two copies, the maximum and minimum of the read values are determined, those values are removed, and 6 Calculate the average of the data and convert the result to NVM
The process of writing to the value of is being performed. Further, when a color is selected, similar processing is performed by modules 127 to 142.

Next, the toner module will be explained with reference to FIGS. 7 and 8. The toner module is called every 10 msec by the standby module and print module. Modules 201 and 203 perform empty processing for color toner, modules 202, 204, and 205 perform empty processing for black toner, module 204 calculates remaining amount prediction from the dispensing time, and module 205 performs empty processing for toner. The bypass time from the cartridge to the empty detection sensor is calculated. The module 206 performs processing in the printing state, and the modules 207, 208, and 209 check the dispense ON time for black toner and color toner, respectively. module 2
The module 10 performs processing when transitioning from the printing state to standby, such as stopping the dispense motor, and the module 211 creates an ADC patch and increases toner when the power is turned on. The module 212 sets the color dispense time, and the module 213 sets the black toner dispense time.
The calculated values of the CDC module are sent via communication, so
In the process of putting this into the dispense buffer, it is multiplied by the correction coefficient calculated by the ADC at this time. The modules 214 and 215 are called at intervals of 100 msec, and check whether the interlock is open or not and whether the toner cartridge is installed.
When the cartridge is replaced, the data related to the toner in NVM is initialized. The module 216 performs post-processing such as incrementing the toner and sending the completion information to the LLM 60. The module 218 is called when the interlock is opened and performs processing related to stopping to interrupt all processing. Also module 22
0 is for processing when the interlock is closed. In FIG. 8, modules 221 to 227 perform color toner increase processing, and modules 228 to 234 perform black toner increase processing, and set the number of repetitions of toner dispensing when the toner increase button is pressed; Setting ON for 5 seconds, O for 5 seconds
Setting the FF, stopping the increase when the number of repetitions reaches a predetermined number, and setting the OFF timer of the suction motor to prevent toner from scattering are performed. This OFF timer setting process turns on the suction motor during toner increase, but turns off the suction motor 15 seconds after the increase ends.
We are taking steps to prevent this from occurring. Modules 235 to 237 are called by the monitor, and are performed only once when the power is turned on. They initialize the dispense buffer, read the contents of NVM to determine what the state was before the power was turned on, and expand this into a flag, for example. If empty toner has already been detected,
Performs processing such as setting the toner empty flag. It also performs the processing when initializing NVM using diagnosis.

FIGS. 9 and 10 are diagrams for explaining the process of moving from the diagnostic mode to the normal mode. First, it is determined whether the mode is diagnostic mode or not. If the diagnostic mode is selected and the code 20-99 is selected, the UI-
I, Diagnosis ADC by CMD-STS module
Flags are set (steps 300, 301, 30
3). If code 20-99 is not selected, other diagnostic processing is performed (step 302), and if the diagnostic ADC flag is set, the normal mode is entered after normal power ON processing ( Step 304).

Next, in FIG. 10, in the state of transition to the normal mode, it is determined whether there is a mode that requires ADC (step 305), and if the mode is necessary, it is checked whether the diagnostic ADC flag is set or not. If it is not set, the RAM is set to output the ADC request signal once every 20 copies, and if the diagnosis ADC flag is set, the ADC request signal is output once every 2 copies and the RAM is set. You will have to set it.

Next, the ADC target value setting process will be explained.

The processing in FIG. 11 is performed by the ADC module, which first determines whether there is a request to create a patch, and if so, creates a patch, samples three ADC sensor outputs of the patch section, and calculates the average. (Steps 310-312). Check whether there is any abnormality in the calculated value, set the ADC fail flag if any, check whether any other ADC fail has occurred, and set the already calculated Vclean and the Vpa calculated in step 312.
Radc is calculated by taking the ratio with tch (steps 313 to 316), and different processes are performed depending on whether black Deve is selected or not. That is, when black Deve is selected and the diagnosis ADC flag is not set in FIG. 12, ADC processing in the black normal mode is performed (steps 318 and 3).
19) Next, if the target value calculation for black has not been completed, check the maximum and minimum of the imported data, and when the 10 patch density data have been acquired, remove 2 data each on the top and bottom of the 10 data. The average value of 6 data is displayed on the black ADC.
Set in NVM as a target value (steps 320-3
23). Then, the black target value calculation end flag is set and the process ends (step 324). Further, as shown in FIG. 13, similar processing is performed in the case of color, and step 331
Determine whether the installed toner color is the standard color or not, and if it is the standard color, add or subtract the offset amount of the toner color to the calculated value to set the target value of each color to each N.
When set in the VM, if the color of the installed toner is not the standard color, the NV corresponding to the color of the installed toner.
Set M as the ADC target value, and set the color target value calculation end flag.

[0020]

As described above, according to the present invention, after adjusting the image quality to the best condition, ADC patches are created more frequently in the copy mode using the diagnosis mode than in the normal mode.
The density data at that time is read and adopted as the ADC target value.The ADC target value is not fixed as in the past, but can be set to a target value that will give the best image quality. The target value can be changed in response to changes in the development curve due to changes in the sensitivity of the developing material or photoreceptor, etc., making it possible to excellently control the reproducibility around 1.0 original density. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of a recording apparatus to which the present invention is applied.

FIG. 2 is a diagram showing the relationship between ADC sensor output and target concentration.

FIG. 3 is a diagram showing the module configuration of the recording device.

[Figure 4]

FIG. 6 is a diagram showing the module configuration of the ADC.

[Figure 7] and

FIG. 8 is a diagram showing the toner module configuration.

[Figure 9] Or

FIG. 13 is a diagram showing a processing flow.

FIG. 14 is a diagram showing a development curve.

[Explanation of symbols]

30...Control device, 31...ADC sensor, 32...Non-volatile memory (NVM), 33, 34...Toner dispense motor.

Claims (3)

[Claims] 1. A control means for forming a reference potential area on a photosensitive material to perform toner development, optically detecting the toner density of the reference potential area, and controlling a toner dispensing motor based on the difference from a target density value. 1. A toner density control method for a printing apparatus, wherein the control means is capable of setting a density target value. 2. The toner density control method for a recording apparatus according to claim 1, wherein the control means is capable of setting a density target value for each toner color. 3. The control means is characterized in that in the self-diagnosis mode, the cycle for creating the reference potential section is shorter than in the normal mode, and the optical density of the reference potential section is detected to automatically set the density target value. 2. A toner density control method for a recording apparatus according to claim 1.