CN113978148B - Dynamic correction method for detecting printer portrait concentration - Google Patents
Dynamic correction method for detecting printer portrait concentration Download PDFInfo
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- CN113978148B CN113978148B CN202111586853.4A CN202111586853A CN113978148B CN 113978148 B CN113978148 B CN 113978148B CN 202111586853 A CN202111586853 A CN 202111586853A CN 113978148 B CN113978148 B CN 113978148B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J29/00—Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for
- B41J29/38—Drives, motors, controls or automatic cut-off devices for the entire printing mechanism
- B41J29/393—Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J29/00—Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for
- B41J29/38—Drives, motors, controls or automatic cut-off devices for the entire printing mechanism
- B41J29/393—Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns
- B41J2029/3935—Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns by means of printed test patterns
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Abstract
The invention discloses a dynamic correction method for detecting the portrait density of a printer, which comprises the following steps: in the (n-1) th correction process, comparing whether the absolute value of the difference between the brightness value of the light reflected by the transfer belt and the target value is less than or equal to a first preset value, and if so, assigning a light-emitting diode driving signal as an actual driving value after correction; if the brightness value in the n-1 correction is larger than the target value, the difference between the value assignment of the driving signal in the n-1 correction and the adjustment step length is used as the actual driving value of the n correction; if the sum of the drive signal assignment and the adjustment step length of the n-1 th correction is smaller than the target value, the drive signal assignment of the nth correction is used; and repeating the correction process until the absolute value of the difference between the brightness value and the target value is less than or equal to a first preset value, and assigning the current driving signal as an actual driving value. The invention realizes dynamic correction of the photoelectric sensor, and avoids the reduction of light source brightness and the lightening of printed images caused by the increase of service life.
Description
Technical Field
The invention relates to the technical field of printer light source brightness correction, in particular to a dynamic correction method for printer portrait concentration detection.
Background
For controlling and monitoring the image density of a printer, it is common practice in the industry to monitor the image density with a compact photoelectric sensor. When the monitored image density is too low or too high, the image density is adjusted by means of adjusting high-voltage output of a high-pressure plate of the printer, LSU luminous brightness and the like, so that the output image density is ensured to be uniform.
The photoelectric sensor consists of a gallium arsenide infrared light-emitting diode with high radiation intensity and two silicon photoelectric transistors; the silicon phototransistor has two receiving terminals, one for receiving the specular reflected P wave of a black image and one for receiving the diffuse reflected S wave of a color image. The common practice in the industry is: the light emitting diode is connected with 5V voltage, and the light source is controlled to be switched ON and OFF by controlling the 5V voltage to be switched ON and OFF.
However, the performance of the light emitting diode gradually weakens with the increase of the service life, the image density fed back by the P wave and the S wave is lower than the actual image density after the light source is weakened, the compensation parameters set inside the printer are not changed, and the density compensation of the printer according to an inaccurate measured value causes the printed image density to be higher than the actually-desired density value.
In addition, the firmware and software of the same type of printer are the same, that is, the concentration compensation parameters are set the same, but the actual output brightness of the light source of each printer under the same current is slightly different, and the difference of the assembly angles of the photoelectric sensors also causes the difference of the reflected P-wave and S-wave values under the conditions of the same current and the same reflectivity of the transfer belt. Moreover, the test is performed again after the manual adjustment, and success cannot be guaranteed, so that a third manual adjustment and a fourth manual adjustment may be added even more times.
In addition, the relative position between the transfer belt and the photoelectric sensor may change slightly due to vibration during transportation, installation and transportation, and the slight change may also affect the reflection path of light, thereby affecting the P value and S value of the light receiving end, and may also cause inaccurate actually monitored image density, resulting in over-compensation or under-compensation.
In addition, the reflectivity is affected by temperature and humidity, and the prior art cannot change along with the change of external environment, so that the monitored density result is inconsistent with the actual image density, and the printer has abnormal image density fault if the printer uses the inaccurate data to compensate the image density.
Chinese patent documents CN102984431B and CN102346408B can be used as references.
Disclosure of Invention
In view of the above-mentioned defects or shortcomings in the prior art, the present invention provides a dynamic correction method for detecting the image density of a printer, which can perform dynamic correction of a photosensor under the current light source status of an led, the current relative angle status of the photosensor and a transfer belt, and the current environmental status of temperature and humidity, and avoid the problem that the brightness of the light source is reduced due to the increase of the service life, thereby causing the printed image to become shallow.
The invention provides a dynamic correction method for detecting the portrait density of a printer, which comprises the following steps:
comparing whether the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value is less than or equal to a first preset value or not in the n-1 th correction process;
if the absolute value is less than or equal to the first preset value, the assignment of the light-emitting diode driving signal is used as the actual driving value of the corrected light-emitting diode driving signal; wherein n is a natural number;
if the absolute value is larger than the first preset value, the correction is carried out for the nth time, if the brightness value of the transfer belt reflection light in the correction process for the (n-1) th time is larger than the target value of the brightness of the transfer belt reflection light, the difference between the assignment of the light emitting diode driving signal in the correction process for the (n-1) th time and the adjustment step length of the light emitting diode driving signal is used as the assignment of the light emitting diode driving signal in the correction process for the nth time; if the transfer belt reflection light brightness value in the n-1 th correction process is smaller than the transfer belt reflection light brightness target value, the sum of the assignment of the light emitting diode driving signal and the adjustment step length of the light emitting diode driving signal in the n-1 th correction process is used as the assignment of the light emitting diode driving signal in the n-1 th correction process;
and repeating the correction process until the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the current correction process is less than or equal to a first preset value, and using the assignment of the LED driving signal in the current correction process as the actual driving value of the LED driving signal.
Further, when the correction triggering condition of image density detection is met, a primary correction step is carried out, and the initial value of the light-emitting diode driving signal, the initial value of the transfer belt reflection light brightness, the transfer belt reflection light brightness target value and the numerical value of the adjustment step length of the light-emitting diode driving signal are configured.
Further, the correction trigger condition includes at least any one of:
starting up the printer for the first time;
receiving a forced correction instruction;
the current external temperature of the printer is different from the external temperature at the previous correction by a first preset temperature;
the current internal temperature of the printer is different from the internal temperature at the previous correction by a second preset temperature;
replacing the transfer printing belt; and the number of the first and second groups,
the image is printed a predetermined number of pages or the print job is completed since the last correction.
Further, if the brightness value of the reflected light of the transfer printing belt in the n-1 th correction process is greater than a second preset value or less than a third preset value, and the second preset value is greater than the third preset value, setting the adjustment step length of the light-emitting diode driving signal in the n-th correction process as a coarse step length value;
if the brightness value of the light reflected by the transfer belt in the n-1 th correction process is less than or equal to a second preset value and greater than or equal to a third preset value, setting the adjustment step length of the light-emitting diode driving signal in the n-1 th correction process as a fine adjustment step length value;
wherein the coarse step size value is greater than the fine step size value.
Further, when the absolute value of the difference between the brightness value of the reflected light of the transfer printing belt and the target brightness value of the reflected light of the transfer printing belt is greater than a first preset value, and the correction times reach or exceed the preset times, the following four conditions are simultaneously satisfied:
the first condition is as follows: the absolute value of the difference between the brightness value of the transfer belt reflected light in the nth correction process and the brightness value of the transfer belt reflected light in the (n-1) th correction process is greater than a fourth preset value, and the fourth preset value is smaller than the first preset value;
and a second condition: the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the n-1 th correction process is smaller than a fifth preset value, and the fifth preset value is larger than the first preset value;
and (3) carrying out a third condition: the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the nth correction process is smaller than a fifth preset value, and the fifth preset value is larger than the first preset value;
and a fourth condition: the brightness value of the transfer belt reflection light in the nth correction process is greater than that in the n-1 th correction process, and the assignment of the LED drive signal in the nth correction process is greater than that in the n-1 th correction process;
the calculation result of the following formula is taken as the actual driving value of the driving signal of the light emitting diode:
wherein the content of the first and second substances,
indicating the assignment of the led driving signal during the nth correction,
indicating the brightness value of the reflected light of the transfer belt in the nth correction process,
indicating the target value of the brightness of the reflected light from the transfer belt,
indicating the assignment of the led driving signal during the (n-1) th calibration,
the brightness value of the reflected light of the transfer belt in the (n-1) th correction process is shown.
Further, when the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value is greater than a first preset value, and the correction times are less than the preset times, and the absolute value of the difference between the transfer belt reflection light brightness value in the nth correction process and the transfer belt reflection light brightness value in the n-1 th correction process is greater than the first preset value, the following steps are executed:
calculated according to the following formula
：
Wherein the content of the first and second substances,
representing the assignment of the LED driving signal in the (n-1) th correction process;
representing the assignment of the LED driving signal in the (n-2) th correction process;
representing the brightness value of the reflected light of the transfer belt in the (n-1) th correction process;
representing the brightness value of the reflected light of the transfer belt in the n-2 correction process;
representing a brightness target value of the reflected light of the transfer printing belt;
the assignment of the LED driving signal when the brightness value of the reflected light of the transfer belt is equal to the target value of the brightness of the reflected light of the transfer belt;
if it is
Is less than
Then will be
And the difference of the adjustment step length of the light-emitting diode driving signal is used as the assignment of the light-emitting diode driving signal in the nth correction process;
if it is
Is greater than
Then will be
And the sum of the adjustment steps of the led driving signals is used as the assignment of the led driving signals in the nth correction process.
Further, if
And
if the absolute value of the difference value is larger than the sixth preset value, setting the adjusting step length of the light-emitting diode driving signal as a coarse adjusting step length value;
if it is
And
if the absolute value of the difference value is less than or equal to the sixth preset value, setting the adjustment step length of the light-emitting diode driving signal as a fine adjustment step length value;
wherein the coarse step size value is greater than the fine step size value.
Further, when the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value is greater than a first preset value, and the correction times are less than the preset times, and the absolute value of the difference between the transfer belt reflection light brightness value in the nth correction process and the transfer belt reflection light brightness value in the n-1 th correction process is less than or equal to the first preset value, the following steps are executed:
if the brightness value of the transfer belt reflection light in the n-1 th correction process is larger than the target value of the brightness of the transfer belt reflection light, taking the difference between the assignment of the light emitting diode driving signal in the n-1 th correction process and the adjustment step length of the light emitting diode driving signal as the actual driving value of the light emitting diode driving signal in the n-1 th correction process;
and if the brightness value of the transfer belt reflection light in the n-1 th correction process is smaller than the target value of the brightness of the transfer belt reflection light, taking the sum of the assignment of the light emitting diode driving signal in the n-1 th correction process and the adjustment step length of the light emitting diode driving signal as the actual driving value of the light emitting diode driving signal in the n-1 th correction process.
Further, if the absolute value of the difference between the transfer belt reflected light brightness value and the transfer belt reflected light brightness target value in the n-1 th correction process is smaller than a fifth preset value, setting the adjustment step length of the light-emitting diode driving signal as a first fine adjustment step length value;
if the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the n-1 th correction process is larger than a fifth preset value, setting the adjusting step length of the light-emitting diode driving signal as a second fine-tuning step length value;
wherein the first fine tuning step size is smaller than the second fine tuning step size.
Further, if the assignment of the light emitting diode driving signal in the n-1 th correction process is smaller than a first limit value, setting the assignment of the light emitting diode driving signal in the n-1 th correction process as the first limit value;
if the assignment of the light emitting diode driving signal in the (n-1) th correction process is larger than the second limit value, setting the assignment of the light emitting diode driving signal in the nth correction process as the second limit value;
wherein the second limit value is greater than the first limit value.
The dynamic correction method for detecting the image concentration of the printer can perform dynamic correction on the photoelectric sensor under the current light source state of the light emitting diode, the current relative angle state of the photoelectric sensor and the transfer belt, the current temperature and humidity and other environmental states, and avoid the problem that the brightness of the light source is reduced due to the increase of the service life, so that the printed image becomes shallow.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic view of a photosensor for detecting image density of a printer according to an embodiment of the present invention;
FIG. 2 is a flowchart of a dynamic calibration method for detecting printer image density according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be understood that although the terms first, second, third, etc. may be used to describe the acquisition modules in the embodiments of the present invention, these acquisition modules should not be limited to these terms. These terms are only used to distinguish the acquisition modules from each other.
The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.
It should be noted that the terms "upper," "lower," "left," "right," and the like used in the description of the embodiments of the present invention are illustrated in the drawings, and should not be construed as limiting the embodiments of the present invention. In addition, in this context, it is also to be understood that when an element is referred to as being "on" or "under" another element, it can be directly formed on "or" under "the other element or be indirectly formed on" or "under" the other element through an intermediate element.
As shown in fig. 1, the distance between the photosensor 100 and the transfer belt is set to 5.5mm in general. The photosensor 100 includes a light emitting diode 101 and two light receiving transistors 102, 103. Wherein the light emitting diode 101 is a high radiant intensity gallium arsenide infrared light emitting diode. The photo transistor 102 is a silicon photo transistor, which is used to receive the S wave diffusely reflected by the transfer belt, and is mainly used to monitor the color image density. The light receiving transistor 103 is also a silicon phototransistor, and is used to receive the P-wave specularly reflected by the transfer belt 104, and is mainly used to monitor the black image density. Since the transfer belt is normally black, the light receiving transistor 103 is also normally used for sensor correction.
The control circuit of the photoelectric Sensor 100 comprises a PWM _ CTD _ Sensor driving signal for controlling the luminous intensity of the light emitting diode 101, and after receiving the specular reflection P wave, the PWM _ CTD _ Sensor driving signal is subjected to photoelectric conversion through a circuit in the photoelectric Sensor 100, and the converted output signal is defined as CTD _ P _ center _ ADC; after receiving the diffuse reflection S wave, the photoelectric conversion is performed by a circuit inside the photoelectric sensor 100, and a converted output signal is defined as CTD _ S _ center _ ADC.
The specular reflection P wave is generally used to monitor the density of black images, and the diffuse reflection S wave is generally used to monitor the density of color images.
The CTD _ S _ center _ ADC and CTD _ P _ center _ ADC signals belong to analog signals and need to be converted into digital signals by an a/D conversion chip. The digital signal is defined as a 10bit magnitude, i.e., a number with a maximum range of 210, i.e., a theoretical maximum of 1023 and a theoretical minimum of 0, the magnitude of the number being related to the monitored concentration. In general, when the encoding rule is defined, the larger the number of definitions, the larger the monitored image density, and the smaller the number, the smaller the monitored image density.
Usually, the CTD _ P _ Centor _ ADC signal is used to detect the density of black image, and the CTD _ S _ Centor _ ADC signal is used to detect the density of color image. Since the transfer belt 104 is normally black, the PWM _ CTD _ Sensor signal and the CTD _ P _ center _ ADC signal are mainly applied for correction in the correction process of the photosensor 100.
The signal PWM _ CTD _ Sensor currently commonly used in the industry to control leds is defined as a fixed value, typically 5V. This method has the disadvantage that the assembling angle of the photoelectric sensor and the assembling angle of the transfer belt 104 are different between different printers, which causes the relative positions of the photoelectric sensor and the transfer belt to be different, thereby affecting the reflectivity. It can be seen that, in this case, the same light emission intensity is defined, and the obtained reflection intensities are different, that is, even if the image density of the actual transfer belt is the same, the monitored image density is different, and in this case, the image density compensation operation performed under an inaccurate measurement value is an erroneous compensation operation. Even in the same printer, the reflectance is changed by a change in the internal or external use environment, and if the light emission intensity of the photosensor is maintained at the initial setting value, the compensation operation is erroneously performed.
To reduce this difference between machines, the method of the present invention is modified to dynamic correction by dynamically changing the value of the PWM _ CTD _ Sensor signal of the machine to obtain the same CTD _ P _ center _ ADC value at the same concentration.
It should be noted that the printing process of the color printer is composed of two transfers, one is the transfer of the toner image from the photosensitive drum to the transfer belt 104, and the other is the transfer of the toner image from the transfer belt 104 to the medium such as paper. Since the reflectance of the transfer belt 104 is relatively high and stable, the color printer image density is preferably monitored by calculation from the color image density on the transfer belt 104.
In this embodiment, under various environmental conditions, the light source emission control current values are automatically calculated by the steps shown in fig. 2 based on the same P-wave and S-wave values obtained in the motion correction process, and the calculated current values are used as the current printer image density compensation.
Specifically, the dynamic calibration method for detecting the image density of the printer provided by this embodiment preferably includes any one of the following calibration trigger conditions:
firstly, when the computer is started for the first time after leaving factory settings. Specifically, before the printer leaves the factory, factory test information including startup and shutdown, printed page number and the like needs to be cleared, and the memory is reset to zero. The first boot after the clearing action is defaulted as the first use of the client, and preferably triggers the correction action of the image density photoelectric sensor.
And secondly, forcibly correcting the image through the operation panel. Specifically, a menu option of a photoelectric sensor for image density is reserved in the operation panel, and when the user thinks that the printing image density is abnormal, the user can perform forced correction through menu selection in the operation panel.
And thirdly, comparing the current external temperature with the external temperature obtained in the previous correction, and keeping the difference between the current external temperature and the external temperature obtained in the previous correction by a first preset temperature, for example, more than 7 ℃. Specifically, the printer has an external temperature and humidity sensor, and when the density correction is performed, the RAM of the printer stores some information other than the compensation information, such as external temperature and humidity information and internal temperature and humidity information. When the current external temperature identified by the external temperature and humidity sensor of the printer is compared with the external temperature stored in the last correction, and the difference between the current external temperature and the external temperature is more than 7 ℃, the correction action of the concentration photoelectric sensor can be preferably triggered at the moment.
And fourthly, comparing the current internal temperature with the internal temperature during the previous correction, and keeping the difference between the current internal temperature and the internal temperature during the previous correction by a second preset temperature, for example, more than 5 ℃. Specifically, the printer has an internal temperature and humidity sensor, and when the density correction is performed, some information other than the compensation information, such as external temperature and humidity information and internal temperature and humidity information, may be stored in the RAM of the printer. When the current internal temperature identified by the temperature and humidity sensor in the printer is compared with the internal temperature stored in the last correction, and the difference is more than 5 ℃, the correction action of the concentration photoelectric sensor can be preferably triggered at the moment.
And fifthly, replacing the new transfer belt. Specifically, the transfer belt of the printer carries an EEPROM memory chip, and when the printer changes the transfer belt, the main control unit recognizes new transfer belt information, and therefore determines that the transfer belt has been changed, and preferably triggers a correction operation of the density photosensor.
And sixthly, starting calculation of the previous correction when the color image is printed for 200 pages or more and the printing task is completed. Specifically, the printer may continuously record the number of printed pages, and store the number of printed pages in the EEPROM memory, and may not clear the pages due to power failure, and when the number of accumulated color printed pages exceeds 200 pages (this value is merely an example, and is not limited to this value) and the current print job is completed from the previous calibration operation, it is preferable that the calibration operation of the density sensor is triggered.
When the printer satisfies one of the six calibration triggering conditions, the main control system of the printer will send a command to execute the dynamic calibration.
The dynamic correction algorithm of the present embodiment proceeds as follows.
In step S101, when the printer satisfies one of the six calibration triggering conditions, the photo sensor triggers a calibration operation to start self-calibration.
Step S102, signal predefining.
Is an initial value set by PWM CTD Sensor,
is the initial value of the CTD _ P _ Centor _ ADC signal, and the photoelectric sensor is corrected for the nth timeCorresponding to
Is a set value of PWM _ CTD _ Sensor corrected at the nth time, wherein, preferably, n is a natural number of 2 or more and 9 or less,
is the value of the n-th corrected CTD _ P _ center _ ADC. K is the adjustment step length, and the actual numerical value is determined according to the self-definition in the algorithm.
Is the target value of the P-wave dynamically corrected by the photosensor.
In step S103, if
And if the default LED light-emitting initial setting value meets the requirement, the correction is successful, and the system executes the next action. The threshold value 5 here indicates that the difference between the transfer belt reflected light luminance value and the transfer belt reflected light luminance target value is within the error of the default of the system, and at this time, it can be considered that the actual luminance value of the transfer belt reflected light reaches the luminance target value. It should be noted that the threshold is set according to specific situations, and the value 5 is merely an example and is not limited in practice.
Step S104: the actual driving value PWM _ CTD _ Sensor of the driving signal of the light emitting diode at this time is equal to the default setting initial value
The value of (c).
Step S105: the dynamic correction process ends.
Step S201: if it is
Then a second correction needs to be performed, at which time the LED emission needs to be adjusted by adjusting the value of PWM _ CTD _ Sensor.
In particular, according to n = n +1, n is corrected for the first time to be equal to 0 and for the second timeThe correction n is 1; at this time, the value of PWM _ CTD _ Sensor light emission is equal to
(ii) a The value of P-wave feedback CTD _ P _ Centor _ ADC is equal to
If, if
Then, then
(ii) a If it is not
Then, then
. Where K denotes the adjustment step size of the led driving signal. That is, if the initial value of the brightness of the light reflected by the transfer belt is greater than the target value, indicating that the brightness is too bright, the brightness needs to be decreased, and therefore the adjustment step is subtracted from the initial value of the driving signal of the light emitting diode as the value assigned to the driving signal of the light emitting diode for the next correction. Similarly, if the initial value of the brightness of the reflected light of the transfer belt is smaller than the target value, which indicates that the brightness is not enough, the brightness needs to be improved, so that the adjustment step length is added on the basis of the initial value of the driving signal of the light-emitting diode to serve as the assignment of the driving signal of the light-emitting diode for the next correction.
Further, if
Greater than 900 or
Less than 100, that is, when the initial value of the brightness of the transfer belt reflected light is too large or too small, the adjustment step K is set to the coarse step value 200. If it is not
Greater than or equal to 100 and
when the value is 900 or less, that is, the initial value of the brightness of the reflected light from the transfer belt is within the normal range, the adjustment step K is set to the fine adjustment step value of 50. The specific numerical values are self-defined according to an actual software and hardware system, and are not actually limited here.
Further, if the calculation result of the assignment of the driving signals of the light emitting diodes in the last correction process is smaller than the lowest limit value or larger than the highest limit value, the assignment of the driving signals of the light emitting diodes in the next correction process is directly set as the lowest limit value or the highest limit value so as to ensure the stable operation of the system.
Continue comparison
And
is large or small, if
If so, the correction is successful, and the value of PWM _ CTD _ Sensor is equal to
If, if
If so, a third calibration is performed.
When the correction is performed for the nth correction and the next correction is the (n + 1) th correction, the value of the PWM _ CTD _ Sensor light emission is equal to
(ii) a The value of P-wave feedback CTD _ P _ Centor _ ADC is equal to
If, if
> 
If so, then
=
-K; if it is not
<
If so, then
=
+ K; if it is not
Greater than 900 or
Less than 100 (i.e., when the transfer belt reflection brightness value of the last correction is too large), K is equal to 200 (i.e., K is roughly adjusted); if it is not
Greater than or equal to 100 and
when the value is 900 or less (i.e., when the value of the transfer belt reflection luminance corrected last time is in the normal range), K is 50 (i.e., K is finely adjusted).
Step S202: judgment of
And
in a relation therebetween, if
Indicates that the correction is successful, and the value of PWM _ CTD _ Sensor is equal to
. When in use
The determination of step S203 is performed. The threshold 5 is merely an example and is not limited to actual.
Step S203: if the value of n is equal to or greater than 9, the determination of step S204 is performed. This step means that after the number of corrections reaches or exceeds the maximum number of corrections, meaning that the brightness value of the transfer belt reflected light cannot be adjusted to the target value for system reasons, at which point the correction is not continued, and step S204 is executed instead.
Step S204: if it is not
And is and
is less than 10, and
less than 10, and
is greater than
And is and
is greater than
Then the correction is stopped, the correction is successful, and step S205 is executed.
It should be noted that the above four conditions are satisfied simultaneously, which means that the difference between the brightness value of the reflected light from the transfer belt and the target value cannot be adjusted within the predetermined error range, but the brightness value of the reflected light from the transfer belt will approach the target brightness value continuously for each correction, and when the previous correction result and the current correction result still have enough difference (b)
) And the deviation of the last correction result from the target value is within a predetermined range (
) When the deviation page of the present correction result and the target value is within a predetermined range (
) It is explained that the correction has been performed a plurality of times so that the luminance value of the transfer belt reflected light is sufficiently close to the target value and it is impossible to reach the set error range, at which time the correction may be stopped.
Step S205: setting the value of PWM _ CTD _ Sensor to
The value of the result is calculated as the actual value of the corrected driving signal of the light emitting diode. Returning to step S105, the correction ends.
Specifically, the PWM _ CTD _ Sensor is actually used to obtain the target value of the brightness of the reflected light
Evaluation of a time-calculated led drive signal
. In the actual scene, the reflected light brightness value
And driving signal of light emitting diode
Linear relationship, assumed in rectangular coordinates
Is a longitudinal axis and is a vertical axis,
on the horizontal axis, then it must satisfy:
derived from the above equation:
derived from the above equation:
derived from the above equation:
step S206: if not satisfied with
And is and
and is and
and is and
is greater than
And is and
is greater than
If any of the conditions is satisfied, the correction fails, and PWM _ CTD _ Sensor is set to 0, and the process returns to step S105.
In step S203, if the value of n is less than 9, the determination of step 301 needs to be performed. The threshold value 9 in this step represents an upper limit of the number of corrections set by the system because it is impossible to allow the printer system to proceed with unlimited corrections in practical applications. The value of the upper threshold is determined according to the actual condition of the system, and is not particularly limited herein.
Step S301: judgment of
And
the relationship between them is determined according to their relationship
The magnitude of the adjustment. If it is not
Then, the adjustment of step S302 is performed; if it is not
Then the adjustment of step S303 is performed.
Step S302: judgment of
And
if there is a relationship of
Then
(ii) a If it is not
Then, then
(ii) a And K is the adjusting step length. This step means that if the last luminance value correction result is larger than the target value, the assignment of the led driving signal is decreased in the next correction process, otherwise the assignment of the led driving signal is increased.
Further, the size of the adjustment step K in step S302 depends on
And
the difference value is greater than 10, and K is 3; if the absolute value of the difference is less than 10, then K is 1. This step means that the brightness value of the transfer belt reflected light has already extremely approximated to the target value after the correction is performed a large number of times, and when the brightness value is approximated to the target value within a certain range, the adjustment step K is further set to a finer fine adjustment value.
Further, according to a rule formula
Or
Calculate out
Then proceeds to step S202.
Step S303: according to
Calculate out
The value of (a) is,
the assignment of the LED driving signal is indicated when the transfer belt reflection light brightness value is equal to the transfer belt reflection light brightness target value.
Indicating the assignment of the led driving signal during the (n-1) th calibration.
Indicating the assignment of the led driving signal during the (n-2) th calibration.
The brightness value of the reflected light of the transfer belt in the (n-1) th correction process is shown.
The brightness value of the reflected light of the transfer belt in the n-2 correction process is shown.
Indicating the target value of the brightness of the reflected light from the transfer belt.
As described above
The calculation derivation process is the same as step S205, and is not described herein again.
Further, calculate out
A value of, if
If it is not
And K is the adjusting step length.
Further, the value of the adjustment step K is the fine adjustment value 50 or the coarse adjustment value 200, depending on whether the value is fine adjustment value or coarse adjustment value
And
the absolute value of the difference of (a). If the absolute value of the difference is greater than 200 or a preset value, the increment is increased every time, the adjusting step length K is set as a coarse adjusting value 200, and if the absolute value of the difference is less than or equal to 200, the increment is not increased every time, the adjusting step length K is set as a fine adjusting value 50.
Further, if
Less than 50, then
Equal to 50, if
Greater than 950, then
Equal to 950. The purpose of this is to set the maximum and minimum values of the led drive signal to allow stable operation of the system.
Further, calculate out
To obtain a value of
Continues to perform the determination of step S202.
According to the above process, n is gradually increased from 1, and the final result is either the successful calibration in step S104, the successful calibration in step S202, or the failed calibration. If the correction fails, the hardware fault is represented, the problem cannot be solved through the dynamic correction scheme, and the hardware fault needs to be checked; and after the hardware troubleshooting is finished, the dynamic correction is carried out.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A dynamic correction method for detecting the image density of a printer is characterized by comprising the following steps:
comparing whether the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value is less than or equal to a first preset value or not in the n-1 th correction process;
if the absolute value is less than or equal to the first preset value, the assignment of the light-emitting diode driving signal is used as the actual driving value of the corrected light-emitting diode driving signal; wherein n is a natural number;
if the absolute value is larger than the first preset value, entering the nth correction, and if the brightness value of the transfer belt reflection light in the nth-1 correction process is larger than the target value of the brightness of the transfer belt reflection light, enabling the difference between the assignment of the light emitting diode driving signal in the nth-1 correction process and the adjustment step length of the light emitting diode driving signal to be used as the assignment of the light emitting diode driving signal in the nth correction process; if the transfer belt reflection light brightness value in the n-1 th correction process is smaller than the transfer belt reflection light brightness target value, the sum of the assignment of the light emitting diode driving signal and the adjustment step length of the light emitting diode driving signal in the n-1 th correction process is used as the assignment of the light emitting diode driving signal in the n-1 th correction process;
and repeating the correction process until the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the current correction process is less than or equal to a first preset value, and using the assignment of the LED driving signal in the current correction process as the actual driving value of the LED driving signal.
2. The method of claim 1, wherein the image density of the printer is detected by a dynamic correction method,
when the correction triggering condition of image concentration detection is met, a first correction step is carried out, and the initial value of the light-emitting diode driving signal, the initial value of the transfer belt reflection light brightness, the transfer belt reflection light brightness target value and the numerical value of the adjustment step length of the light-emitting diode driving signal are configured.
3. The method of claim 2, wherein the trigger condition includes at least one of the following conditions:
starting up the printer for the first time;
receiving a forced correction instruction;
the current external temperature of the printer is different from the external temperature at the previous correction by a first preset temperature;
the current internal temperature of the printer is different from the internal temperature at the previous correction by a second preset temperature;
replacing the transfer printing belt; and the number of the first and second groups,
the image is printed a predetermined number of pages or the print job is completed since the last correction.
4. The method of claim 1, further comprising the steps of:
if the brightness value of the light reflected by the transfer belt in the n-1 th correction process is greater than a second preset value or less than a third preset value, and the second preset value is greater than the third preset value, setting the adjustment step length of the light-emitting diode driving signal in the n-1 th correction process as a coarse adjustment step length value;
if the brightness value of the light reflected by the transfer belt in the n-1 th correction process is less than or equal to a second preset value and greater than or equal to a third preset value, setting the adjustment step length of the light-emitting diode driving signal in the n-1 th correction process as a fine adjustment step length value;
the coarse step size value is greater than the fine step size value.
5. The method of claim 1, further comprising the steps of:
when the absolute value of the difference between the brightness value of the reflected light of the transfer printing belt and the target brightness value of the reflected light of the transfer printing belt is larger than a first preset value, the correction times reach or exceed the preset times, and the following four conditions are simultaneously met:
the first condition is as follows: the absolute value of the difference between the brightness value of the transfer belt reflected light in the nth correction process and the brightness value of the transfer belt reflected light in the (n-1) th correction process is greater than a fourth preset value, and the fourth preset value is smaller than the first preset value;
and a second condition: the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the n-1 th correction process is smaller than a fifth preset value, and the fifth preset value is larger than the first preset value;
and (3) carrying out a third condition: the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the nth correction process is smaller than a fifth preset value, and the fifth preset value is larger than the first preset value;
and a fourth condition: the brightness value of the transfer belt reflection light in the nth correction process is greater than that in the n-1 th correction process, and the assignment of the LED drive signal in the nth correction process is greater than that in the n-1 th correction process;
the calculation result of the following formula is taken as the actual driving value of the led driving signal:
wherein the content of the first and second substances,
indicating the assignment of the led driving signal during the nth correction,
indicating the brightness value of the reflected light of the transfer belt in the nth correction process,
indicating the target value of the brightness of the reflected light from the transfer belt,
indicating the assignment of the led driving signal during the (n-1) th calibration,
the brightness value of the reflected light of the transfer belt in the (n-1) th correction process is shown.
6. The method of claim 1, further comprising the steps of:
when the absolute value of the difference between the brightness value of the transfer belt reflected light and the target value of the brightness of the transfer belt reflected light is greater than a first preset value, and the correction times are less than the preset times, and the absolute value of the difference between the brightness value of the transfer belt reflected light in the nth correction process and the brightness value of the transfer belt reflected light in the n-1 th correction process is greater than the first preset value, executing the following steps:
calculated according to the following formula
：
Wherein the content of the first and second substances,
representing the assignment of the LED driving signal in the (n-1) th correction process;
representing the assignment of the LED driving signal in the (n-2) th correction process;
representing the brightness value of the reflected light of the transfer belt in the (n-1) th correction process;
representing the brightness value of the reflected light of the transfer belt in the n-2 correction process;
representing a brightness target value of the reflected light of the transfer printing belt;
the assignment of the LED driving signal when the brightness value of the reflected light of the transfer belt is equal to the target value of the brightness of the reflected light of the transfer belt;
if it is
Is less than
Then will be
And the difference of the adjustment step length of the light-emitting diode driving signal is used as the assignment of the light-emitting diode driving signal in the nth correction process;
if it is
Big (a)In that
Then will be
And the sum of the adjustment steps of the led driving signals is used as the assignment of the led driving signals in the nth correction process.
7. The method of claim 6, further comprising the step of:
if it is
And
if the absolute value of the difference value is larger than the sixth preset value, setting the adjusting step length of the light-emitting diode driving signal as a coarse adjusting step length value;
if it is
And
if the absolute value of the difference value is less than or equal to the sixth preset value, setting the adjustment step length of the light-emitting diode driving signal as a fine adjustment step length value;
the coarse step size value is greater than the fine step size value.
8. The method of claim 1, further comprising the steps of:
when the absolute value of the difference between the brightness value of the transfer belt reflected light and the target value of the brightness of the transfer belt reflected light is greater than a first preset value, and the correction times are less than the preset times, and the absolute value of the difference between the brightness value of the transfer belt reflected light in the nth correction process and the brightness value of the transfer belt reflected light in the n-1 th correction process is less than or equal to the first preset value, the following steps are executed:
if the brightness value of the transfer belt reflection light in the n-1 th correction process is larger than the target value of the brightness of the transfer belt reflection light, taking the difference between the assignment of the light emitting diode driving signal in the n-1 th correction process and the adjustment step length of the light emitting diode driving signal as the actual driving value of the light emitting diode driving signal in the n-1 th correction process;
and if the brightness value of the transfer belt reflection light in the n-1 th correction process is smaller than the target value of the brightness of the transfer belt reflection light, taking the sum of the assignment of the light emitting diode driving signal in the n-1 th correction process and the adjustment step length of the light emitting diode driving signal as the actual driving value of the light emitting diode driving signal in the n-1 th correction process.
9. The method of claim 8, further comprising the step of:
if the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the n-1 th correction process is smaller than a fifth preset value, setting the adjustment step length of the light-emitting diode driving signal as a first fine adjustment step length value;
if the absolute value of the difference between the transfer belt reflection light brightness value and the transfer belt reflection light brightness target value in the n-1 th correction process is larger than a fifth preset value, setting the adjusting step length of the light-emitting diode driving signal as a second fine-tuning step length value;
the first trim step value is less than the second trim step value.
10. The method of claim 4, wherein the method further comprises:
if the assignment of the light emitting diode driving signal in the (n-1) th correction process is smaller than a first limit value, setting the assignment of the light emitting diode driving signal in the nth correction process as the first limit value;
if the assignment of the light emitting diode driving signal in the (n-1) th correction process is larger than the second limit value, setting the assignment of the light emitting diode driving signal in the nth correction process as the second limit value;
the second limit value is greater than the first limit value.
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| CN101060990A (en) * | 2004-09-21 | 2007-10-24 | Z公司 | Test pattern and alignment method for 3d printers |
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| JP2020168779A (en) * | 2019-04-02 | 2020-10-15 | キヤノン株式会社 | Image formation apparatus, control method of the same and program |
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| JP6070636B2 (en) * | 2014-06-04 | 2017-02-01 | コニカミノルタ株式会社 | Image forming apparatus |
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|---|---|---|---|---|
| CN101060990A (en) * | 2004-09-21 | 2007-10-24 | Z公司 | Test pattern and alignment method for 3d printers |
| JP2012053089A (en) * | 2010-08-31 | 2012-03-15 | Konica Minolta Business Technologies Inc | Image forming apparatus and image forming method |
| CN111196087A (en) * | 2018-11-19 | 2020-05-26 | 柯尼卡美能达株式会社 | Image forming apparatus, shading correction method for image forming apparatus, and recording medium |
| JP2020168779A (en) * | 2019-04-02 | 2020-10-15 | キヤノン株式会社 | Image formation apparatus, control method of the same and program |
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