Image forming apparatus, image density stabilization control method, and storage medium
阅读说明:本技术 图像形成装置、图像浓度稳定化控制方法 (Image forming apparatus, image density stabilization control method, and storage medium ) 是由 西村泰浩 于 2019-07-10 设计创作,主要内容包括:一种图像形成装置,通过电子照片方式形成图像,所述图像形成装置的特征在于,具备:感光体;带电器,其在打印时使所述感光体带电;带电电位变动预测部,其预测所述感光体的带电电位的变动量;光扫描装置,其向所述感光体照射曝光激光而形成静电潜像;显影部,其对所述静电潜像进行显影;以及曝光激光输出补正部,其对所述曝光激光的输出进行补正,所述带电电位变动预测部根据带电停止时间预测打印停止后的所述带电电位的变动量,所述曝光激光输出补正部根据所述带电电位的变动量对应该向所述感光体照射的所述曝光激光的输出进行补正,从而降低由所述带电电位的变动引起的所述图像的浓度变化。(An image forming apparatus that forms an image by an electrophotographic method, comprising: a photoreceptor; a charger that charges the photoreceptor at the time of printing; a charge potential variation prediction unit that predicts a variation amount of a charge potential of the photoreceptor; an optical scanning device that irradiates the photoreceptor with exposure laser light to form an electrostatic latent image; a developing section that develops the electrostatic latent image; and an exposure laser output correction unit that corrects an output of the exposure laser, wherein the charge potential variation prediction unit predicts a variation amount of the charge potential after printing is stopped, based on a charge stop time, and the exposure laser output correction unit corrects an output of the exposure laser to be irradiated to the photoreceptor, based on the variation amount of the charge potential, so as to reduce a density variation of the image caused by the variation of the charge potential.)
1. An image forming apparatus for forming an image by an electrophotographic method,
the image forming apparatus is characterized by comprising:
a photoreceptor;
a charger that charges the photoreceptor at the time of printing;
a charge potential variation prediction unit that predicts a variation amount of a charge potential of the photoreceptor;
an optical scanning device that irradiates the photoreceptor with exposure laser light to form an electrostatic latent image;
a developing section that develops the electrostatic latent image; and
an exposure laser output correction unit for correcting the output of the exposure laser,
the charging potential variation predicting section predicts a variation amount of the charging potential after printing is stopped based on a charging stop time,
the exposure laser output correction unit corrects the output of the exposure laser to be irradiated onto the photoreceptor in accordance with the amount of change in the charging potential, thereby reducing the change in the density of the image due to the change in the charging potential.
2. The image forming apparatus according to claim 1,
the exposure laser output correction unit determines a correction amount of the output of the exposure laser based on the charging stop time,
the optical scanning device irradiates the photoreceptor with exposure laser light having an output obtained by subtracting the correction amount from an output of the exposure laser light to be irradiated onto the photoreceptor, without a variation in the charged potential.
3. The image forming apparatus according to claim 2,
when the charging stop time is shorter than a preset reference time, the exposure laser output correction unit determines a correction amount of the output of the exposure laser such that the shorter the charging duration of the charger, the larger the correction amount of the output of the exposure laser.
4. The image forming apparatus according to any one of claims 1 to 3,
further comprises a temperature/humidity sensor for sensing the temperature and humidity around the image forming apparatus,
the exposure laser output correction unit increases or decreases a correction amount of the output of the exposure laser according to the temperature and the humidity.
5. The image forming apparatus according to claim 4,
in the exposure laser output correction unit, the correction amount of the output of the exposure laser is increased as the temperature and the humidity are decreased.
6. An image density stabilization control method for an image forming apparatus for forming an image by an electrophotographic method,
the image density stabilization control method is characterized by comprising the following steps:
a charging step of charging the photoreceptor at the time of printing;
a charged potential variation prediction step of predicting a variation amount of a charged potential of the photoreceptor;
a light scanning step of irradiating the photosensitive body with exposure laser light to form an electrostatic latent image;
a developing step of developing the electrostatic latent image; and
an exposure laser output correction step of correcting the output of the exposure laser,
in the charging potential variation predicting step, a variation amount of the charging potential after printing is stopped is predicted based on a charging stop time,
in the exposure laser output correction step, the output of the exposure laser to be irradiated onto the photoreceptor is corrected based on the amount of fluctuation of the charged potential, thereby reducing the density change of the image due to the fluctuation of the charged potential.
7. A computer-readable recording medium having recorded thereon an image density stabilization control program to be executed by an image forming apparatus that forms an image by an electrophotographic method,
the recording medium is characterized in that it is,
causing a processor of the image forming apparatus to perform the steps of:
a charging step of charging the photoreceptor at the time of printing;
a charged potential variation prediction step of predicting a variation amount of a charged potential of the photoreceptor;
a light scanning step of irradiating the photosensitive body with exposure laser light to form an electrostatic latent image;
a developing step of developing the electrostatic latent image; and
an exposure laser output correction step of correcting the output of the exposure laser,
in the charging potential variation predicting step, a variation amount of the charging potential after printing is stopped is predicted based on a charging stop time,
in the exposure laser output correction step, the output of the exposure laser to be irradiated onto the photoreceptor is corrected based on the amount of fluctuation of the charged potential, thereby reducing the density change of the image due to the fluctuation of the charged potential.
Technical Field
The present invention relates to an image forming apparatus, an image density stabilization control method, an image density stabilization control program, and a recording medium, and more particularly, to an electrophotographic image forming apparatus, an image density stabilization control method for an electrophotographic image forming apparatus, an image density stabilization control program, and a recording medium.
Background
It is known that when an electrophotographic image forming apparatus is left in a low humidity environment, the charging potential immediately after the charging application to the photosensitive drum is reduced, and this phenomenon changes the electrostatic adhesion of toner, and thus the image density is likely to change.
In particular, when the potential of the photoreceptor fluctuates immediately after the completion of the charging application, the density of the first and second images changes, and such a phenomenon is particularly conspicuous in a low-humidity environment.
In order to solve such a problem, an invention has been conventionally disclosed in which an image forming apparatus includes a control unit that controls the image exposure device based on a use environment condition, a use history, and a stop time, so that an image exposure amount of the image exposure device in a portion facing the charging device when the photosensitive drum is stopped is variable to secure a uniform bright portion potential at the time of next image formation, and a sensitivity drop of a surface of a photoreceptor of the charging device is corrected to prevent an image failure such as disturbance of an image or unevenness of density of the image from occurring (for example, see patent document 1).
Disclosure of Invention
Technical problem to be solved by the invention
However, in the conventional technique of varying the light amount of the image exposure device and the amount of charge removed by the charge removal device based on the use environment conditions, the use history, and the stop time, a uniform bright portion potential can be secured at the time of image formation after the second time, but a new technique for preventing the above-described problem is required for the change in image density caused by the change in image density particularly immediately after the end of charge application at the time of the first image formation.
The present invention has been made in view of the above circumstances, and provides an image forming apparatus, an image density stabilization control method, an image density stabilization control program, and a computer-readable recording medium having the image density stabilization control program recorded thereon, which effectively reduce image density variations caused by a decrease in a charging potential immediately after charging application to a photoreceptor, as compared to the conventional art.
Means for solving the problems
The present invention provides an image forming apparatus for forming an image by an electrophotographic method, the image forming apparatus comprising: a photoreceptor; a charger that charges the photoreceptor at the time of printing; a charge potential variation prediction unit that predicts a variation amount of a charge potential of the photoreceptor; an optical scanning device that irradiates the photoreceptor with exposure laser light to form an electrostatic latent image; a developing section that develops the electrostatic latent image; and an exposure laser output correction unit that corrects an output of the exposure laser, wherein the charge potential variation prediction unit predicts a variation amount of the charge potential after printing is stopped, based on a charge stop time, and the exposure laser output correction unit corrects the output of the exposure laser irradiated to the photoreceptor, based on the variation amount of the charge potential, so as to reduce a density variation of the image caused by the variation of the charge potential.
Further, the present invention provides an image density stabilization control method for an image forming apparatus that forms an image by an electrophotographic method, the image density stabilization control method comprising: a charging step of charging the photoreceptor at the time of printing; a charged potential variation prediction step of predicting a variation amount of a charged potential of the photoreceptor; a light scanning step of irradiating the photosensitive body with exposure laser light to form an electrostatic latent image; a developing step of developing the electrostatic latent image; and an exposure laser output correction step of correcting an output of the exposure laser, wherein the charge potential variation prediction step predicts a variation amount of the charge potential after the printing is stopped, based on a charge stop time, and the exposure laser output correction step corrects the output of the exposure laser irradiated to the photoreceptor, based on the variation amount of the charge potential, so as to reduce a density change of the image due to the variation of the charge potential.
Further, the present invention provides an image density stabilization control program to be executed by an image forming apparatus that forms an image by an electrophotographic method, the image density stabilization control program causing a processor of the image forming apparatus to execute: a charging step of charging the photoreceptor at the time of printing; a charged potential variation prediction step of predicting a variation amount of a charged potential of the photoreceptor; a light scanning step of irradiating the photosensitive body with exposure laser light to form an electrostatic latent image; a developing step of developing the electrostatic latent image; and an exposure laser output correction step of correcting an output of the exposure laser, wherein the charge potential variation prediction step predicts a variation amount of the charge potential after the printing is stopped, based on a charge stop time, and the exposure laser output correction step corrects the output of the exposure laser irradiated to the photoreceptor, based on the variation amount of the charge potential, to reduce a density change of the image due to the variation of the charge potential.
Further, the present invention provides a computer-readable recording medium having an image density stabilization control program recorded thereon, the image density stabilization control program being executed by an image forming apparatus that forms an image by an electrophotographic method, the recording medium causing a processor of the image forming apparatus to execute: a charging step of charging the photoreceptor at the time of printing; a charged potential variation prediction step of predicting a variation amount of a charged potential of the photoreceptor; a light scanning step of irradiating the photosensitive body with exposure laser light to form an electrostatic latent image; a developing step of developing the electrostatic latent image; and an exposure laser output correction step of correcting an output of the exposure laser, wherein the charge potential variation prediction step predicts a variation amount of the charge potential after the printing is stopped, based on a charge stop time, and the exposure laser output correction step corrects the output of the exposure laser irradiated to the photoreceptor, based on the variation amount of the charge potential, so as to reduce a density change of the image due to the variation of the charge potential.
In the present invention, an "image forming apparatus" is an apparatus that forms and outputs an image, such as a copier having a copying (copying) function, such as an electrophotographic printer, or an MFP (multi functional Peripheral) including a function other than copying.
Effects of the invention
According to the present invention, by detecting the charging stop time after the printing is stopped and correcting the exposure laser output of the photoreceptor based on the charging stop time, it is possible to realize an image forming apparatus, an image density stabilization control method, an image density stabilization control program, and a computer-readable recording medium on which the image density stabilization control program is recorded, which effectively reduce the image density variation due to the decrease in the charging potential immediately after the charging application to the photoreceptor ends, as compared to the conventional one.
Preferred embodiments of the present invention will be described.
(2) The exposure laser output correction unit may determine a correction amount of the output of the exposure laser light based on the charging stop time, and the optical scanning device may irradiate the photosensitive body with the output of the exposure laser light obtained by subtracting the correction amount from the output of the exposure laser light to be irradiated to the photosensitive body when the charging potential does not vary.
In this way, the amount of correction of the output of the exposure laser can be determined in accordance with the charging stop time, and therefore an image forming apparatus is realized that effectively reduces the image density variation caused by the decrease in the charging potential immediately after the charging application to the photoreceptor.
(3) In the case where the charging stop time is shorter than a preset reference time, the exposure laser output correction unit may determine the correction amount of the output of the exposure laser such that the correction amount of the output of the exposure laser increases as the charging duration of the charger decreases.
In this way, the exposure laser output correction unit determines the amount of correction of the output of the exposure laser such that the amount of correction of the output of the exposure laser increases as the charging duration of the charger becomes shorter, and thus it is possible to realize an image forming apparatus that effectively reduces the change in image density due to the decrease in the charging potential immediately after the charging application to the photoreceptor ends, compared to the conventional one.
(4) The image forming apparatus may further include a temperature/humidity sensor that senses a temperature and a humidity around the image forming apparatus, and the exposure laser output correction unit may increase or decrease a correction amount of the output of the exposure laser based on the temperature and the humidity.
In this way, the exposure laser output correction unit increases or decreases the amount of correction of the output of the exposure laser in accordance with the temperature and humidity around the image forming apparatus, and therefore, an image forming apparatus can be realized that effectively reduces the change in image density due to the decrease in the charging potential immediately after the charging application to the photoreceptor as compared to the conventional one.
(5) In the exposure laser output correction unit, the correction amount of the output of the exposure laser may be increased as the temperature and the humidity decrease.
In this way, in the exposure laser output correction unit, the correction amount of the output of the exposure laser is increased as the temperature and humidity around the image forming apparatus are decreased, and therefore, it is possible to realize an image forming apparatus in which the change in image density due to the decrease in the charging potential immediately after the charging application to the photosensitive drum is completed can be effectively reduced as compared with the conventional one.
Drawings
Fig. 1 is a perspective view showing an external appearance of a digital multifunction peripheral as an embodiment of an image forming apparatus according to the present invention.
Fig. 2 is a cross-sectional view showing a mechanism configuration of a main body portion of the digital multifunction peripheral shown in fig. 1.
Fig. 3 is a block diagram showing a schematic configuration of the digital multifunction peripheral shown in fig. 1.
Fig. 4 is an explanatory diagram showing an outline of image density stabilization control of the digital multifunction peripheral shown in fig. 1.
Fig. 5 is a flowchart showing a process of image density stabilization control of the digital multifunction peripheral shown in fig. 1.
Fig. 6 is an example of a basic correction table showing a relationship between the accumulated time after the start of charging of the photosensitive drum and the correction amount.
Fig. 7 is an example of a table for specifying the correction start PHASE and the correction coefficient of the stop time of the photoconductive drum.
Fig. 8 is an example of a correction coefficient table showing the lifetime of the photoconductive drum.
Fig. 9 is an example of an environment level table of the ambient temperature and the relative humidity of the digital multifunction peripheral.
Fig. 10 is an example of a correction coefficient table of the environmental level.
Fig. 11 is an example of a correction coefficient table of the process speed of the photosensitive drum.
Fig. 12 is an example of a correction coefficient table of the development bias of the photoconductive drum.
Fig. 13 is an example of a correction coefficient table of the history of the photosensitive drum.
Fig. 14 is an explanatory diagram illustrating an example of correction of the exposure laser output of the photosensitive drum.
Fig. 15 is a graph showing a change in the charged potential of the photosensitive drum and a correction example thereof when printing is performed on two sheets of paper in the digital multifunction peripheral according to the second embodiment.
Fig. 16 is a graph showing an example of a change in a charged potential of each concentration portion of the photosensitive drum in the digital multifunction peripheral according to the third embodiment.
Detailed Description
The present invention will be described in further detail below with reference to the accompanying drawings. In addition, all aspects of the following description are exemplary and should not be construed as limiting the invention.
[ first embodiment ]
A digital multifunction peripheral 1 as an embodiment of an image forming apparatus according to the present invention will be described with reference to fig. 1 to 3.
Fig. 1 is a perspective view showing an external appearance of a digital multifunction peripheral 1 as an embodiment of an image forming apparatus according to the present invention. Fig. 2 is a cross-sectional view showing a mechanism configuration of a main body portion of the digital multifunction peripheral 1 shown in fig. 1.
The digital multifunction Peripheral 1 is an apparatus such as an MFP (multi functional Peripheral) that performs digital processing on image data and has a copy function, a scanner function, and a facsimile function (see fig. 1).
As shown in fig. 2, the digital multifunction peripheral 1 includes a document feeder 112 for feeding a document to a reading unit, a document reader 111 for reading the document, and an
< Structure of digital multifunction peripheral 1 >
Here, the internal configuration of the digital multifunction peripheral 1 shown in fig. 2 will be briefly described in advance.
In the digital multifunction peripheral 1, color images using respective colors of black (K), cyan (C), magenta (M), and yellow (Y) are printed on a printing sheet. Alternatively, a monochrome image using a single color (for example, black) is printed on the printing paper. Therefore, four developing
In any one of the respective image stations Pa, Pb, Pc, Pd, a toner image is formed as follows. The
Further, the
The printing paper is pulled out from any one of the four
A nip area is formed between the transfer roller 23a of the
The printing paper sheet having passed through the fixing
Next, a schematic configuration of the digital multifunction peripheral 1 will be described with reference to fig. 3.
Fig. 3 is a block diagram showing a schematic configuration of the digital multifunction peripheral 1 shown in fig. 1.
As shown in fig. 3, the digital multifunction peripheral 1 includes a
Hereinafter, each component of the digital multifunction peripheral 1 will be described.
The
The
The
The
The
The
Further, the program and the data may be held in different devices so that the area for holding the data is constituted by a hard disk drive and the area for holding the program is constituted by a flash memory.
The
The
The
The
The
The
The
The temperature/
The "photoreceptor" of the present invention is realized by the
< control of stabilizing image density in digital multifunction peripheral 1 >
Next, the image density stabilization control of the digital multifunction peripheral 1 according to the first embodiment of the present invention will be described with reference to fig. 4 to 14.
Fig. 4 is an explanatory diagram showing an outline of the image density stabilization control of the digital multifunction peripheral 1 shown in fig. 1. Fig. 5 is a flowchart showing the image density stabilization control process of the digital multifunction peripheral 1 shown in fig. 1. Fig. 6 is an example of a basic correction table showing a relationship between the accumulated time after the start of charging of the
Fig. 4 shows an outline of the image density stabilization control of the digital multifunction peripheral 1 according to the first embodiment of the present invention.
The horizontal axis of fig. 4 a represents time, and the vertical axis represents the charging potential (arbitrary unit) of the
Note that the broken line graph in fig. 4 (a) shows the charging potential in a normal state, and the solid line graph shows the charging potential in a case where fluctuation occurs.
As shown in fig. 4 (a), when the charging potential of the
The variation in the charge potential is remarkable particularly immediately after the end of the charge application, and then decreases little by little.
Therefore, as shown in fig. 4 (B), the exposure laser output value of the
Fig. 5 shows an example of the process of the image density stabilization control of the digital multifunction peripheral 1 according to the first embodiment of the present invention.
In fig. 5, when receiving a request for starting charging control of the
Specifically, the
After that, the
The
If the stop time from the last charging stop is less than 10 seconds (yes in step S1),
Specifically, the
In the basic correction table of fig. 6, for example, when the cumulative time of charging of the
In addition, the presence of "X to Y" in the numerical range of the table in fig. 6 indicates "X or more and less than Y". The same applies to fig. 8, 9, 12, and 13.
After that, for example, when the charging is stopped at "
On the other hand, in step S1 of fig. 5, when the charging stop time from the previous charging stop is 10 seconds or longer (no in step S1), the
Specifically, the
In fig. 7 (a), the symbol [ x ] in the right formula represents the integer part of x.
For example, when the charging stop time is 100 seconds, since PHASE is 3 according to the formula (a) of fig. 7, the
As shown in the table of fig. 7 (B), the formula of fig. 7 (a) is applied to the case where the charging stop time is 10 seconds or more and less than 120 seconds.
On the other hand, when the charging stop time is 120 seconds or longer, the PHASE1 starts as shown in the table (B) of fig. 7.
For example, when the charging stop time is 30 hours, since the PHASE is 1 according to the table (B) of fig. 7, the
Next, in fig. 5, after the process of step S2 or S3 is finished, the
Specifically, the
LDP_revise=Re_mul×k_ti×kl_x×k_ev×k_ps×k_dvb×k_us
Here, the basic correction amount Re _ mul, the correction coefficients kl _ x, k _ ev, k _ ps, k _ dvb, k _ us, and k _ ti are defined as follows.
(1) Re _ mul: basic correction amount of exposure laser output
(2) k _ ti: correction coefficient corresponding to charging stop time
(3) kl _ x: correction coefficient corresponding to the film reduction correction count of the
(4) k _ ev: correction coefficient corresponding to environmental level
(5) k _ ps: correction coefficient corresponding to progress speed
(6) k _ dvb: correction coefficient corresponding to developing bias value
(7) k _ us: correction coefficient corresponding to history
The basic correction amount and each correction coefficient of the exposure laser output will be described in detail below.
(1) Basic correction Re _ mul of exposure laser output
The
Further, the basic correction amount Re _ mul of the exposure laser output also differs depending on the process speed (linear velocity) (mm/sec) of the
For example, in the PHASE10, the basic correction amount Re _ mul is 2, 5, and 7 at 100 (mm/sec), 200 (mm/sec), and 300 (mm/sec), respectively, according to the table of fig. 6.
(2) Correction coefficient k _ ti corresponding to charging stop time
The
For example, as shown in the table (B) of fig. 7, when the charging stop time is 10 seconds or more and less than 120 seconds, the correction coefficient k _ ti is calculated to be 1.1 when the correction coefficient k _ ti is 1.0 and the charging stop time is 120 seconds or more and less than 600 seconds, and the correction coefficient k _ ti is calculated to be 1.3 when the charging stop time is 1 hour or more and less than 2 hours.
(3) Correction coefficient kl _ x corresponding to the film reduction correction count of the
The
Specifically, as shown in the table of fig. 8, the correction coefficient kl _ x is calculated to be 1.0 if the ratio of the charging control time (ratio of the charging control time with respect to the lifetime) of the
The
(4) Correction coefficient k _ ev corresponding to environmental level
When the charging control of the
Specifically, as shown in the table of fig. 9, the
For example, in the case where the relative humidity is 40% or more and less than 50%, and the temperature is 20 ℃ or more and less than 25 ℃, the environmental level value is 4.
In the table of fig. 9, the environmental level value is closer to 1 in a low-humidity and low-temperature environment, and the environmental level value is closer to 10 in a high-humidity and high-temperature environment.
The
For example, when the environmental level value is 4, the correction coefficient k _ ev is 1.0.
(5) Correction coefficient k _ ps corresponding to process speed
The
As shown in the table of fig. 11, the correction coefficient k _ ps is determined for the process speeds (mm/sec) of 100, 200, and 300.
For example, when the process speed is 200 mm/sec, the correction coefficient k _ ps is 1.0.
(6) Correction coefficient k _ dvb corresponding to development bias value
The
As shown in the table of fig. 12, the correction coefficient k _ dvb corresponding to the development bias value (V) as a result of the process control is determined.
For example, when the developing bias value is 251 or more and less than 350, the correction coefficient k _ dvb is 0.8.
(7) Correction coefficient k _ us corresponding to history
The
In the example of fig. 13, "the charging time of the
As shown in the table of fig. 13, the correction coefficient k _ us corresponding to the charging time (minutes) of the
For example, when the charging time of the
When the stop time detected when the charging control of the
The
Further, the
In this way, the
Next, in step S5 of fig. 5,
Next, in step S6, the
Specifically, the
Next, in step S7, the
When the PHASE30 is reached (yes in step S7), the
After that, the
On the other hand, if the PHASE30 is not reached (no in step S7), the
As a result, as shown in fig. 14, the correction amount of the exposure laser output is stepwise corrected based on the charging duration from the start of charging control of the
In the example of FIG. 14, the exposure laser output is corrected in stages by-10% for the first facet, -6% for the second facet, -2% for the third facet, -1% for the fourth facet, -0.5% for the fifth facet, and 0% for the sixth facet.
By detecting the time when the
[ second embodiment ]
Next, an example of image density stabilization control in the digital multifunction peripheral 1 according to the second embodiment will be described with reference to fig. 15.
Fig. 15 is a graph showing a change in the charged potential of the
The change in the charged potential of the
In addition, for simplicity, printing of the first sheet is performed up to 100 milliseconds, and printing of the second sheet is performed up to 200 milliseconds.
In the graph of fig. 15, the horizontal axis represents the charging time (milliseconds), and the vertical axis represents the charging potential (-V) of the
The dashed line graph shows the change in the charging potential before correction, and the solid line graph shows the change in the charging potential after correction.
As shown by the broken line graph in fig. 15, immediately after the end of printing on the first sheet of paper before correction, it is regarded as a decrease in the charged potential.
Therefore, in the second embodiment, as shown by the solid line graph in fig. 15, the background portion of-600V and the high density portion of-100V are corrected so as to have a constant charging potential.
The
In this way, when a plurality of sheets of print are performed, by appropriately correcting the exposure laser output according to the number of prints, it is possible to realize the digital multifunction peripheral 1 that effectively reduces the image density variation due to the reduction in the charging potential immediately after the charging application to the
[ third embodiment ]
Next, an example of image density stabilization control in the digital multifunction peripheral 1 according to the third embodiment will be described with reference to fig. 16.
Fig. 16 is a graph showing an example of a change in the charging potential of each concentration portion of the
The change in the charged potential of the
In the graph of fig. 16, the horizontal axis represents the change in the charging potential of the
In addition, in each concentration portion, when the correction is not performed in the order from the left, the change of the charged potential in the high-concentration correction application and the low-concentration correction application is shown.
The following table shows changes in the charge potential in each concentration portion.
[ Table 1]
Application of correction
Low concentration part
Middle concentration part
High concentration part
Without correction
-10V
-25V
-40V
When the correction is applied to medium concentration
30V
10V
0V
When used for correction of high concentration
0V
-15V
-20V
The effects of the low-concentration portion and the high-concentration portion differ depending on the amount of correction.
For example, in the case of the correction application for low density, although the density of the low density portion is matched, the high density portion is not sufficiently improved.
On the other hand, in the case of the correction application for high density, although the density of high density is matched, the density becomes conversely lighter in the low density portion.
Accordingly, the
In the example of fig. 16, the case of three of the low, middle, and high concentration portions, and the case of two concentration correction applications in the case of the high concentration correction application and the case of the low concentration correction application are described, but corrections corresponding to more various concentration portions and concentration corrections may be implemented.
By appropriately correcting the exposure laser output corresponding to the difference in density among the low-density portion, the intermediate-density portion, and the high-density portion in this manner, the digital multifunction peripheral 1 is realized that effectively reduces the change in image density due to the reduction in the charging potential immediately after the charging application to the
A preferred embodiment of the present invention includes a combination of any of the above-described embodiments.
In addition to the above-described embodiments, various modifications can be made to the present invention. It should not be construed that the above-described modifications do not fall within the scope of the present invention. The present invention is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.
Description of the reference numerals
1: a digital compound machine; 11: an optical scanning device; 12: a developing device; 13: a photosensitive drum; 14: a drum cleaning device; 15: charging an electric appliance; 17: fixing device, 18: a feeding tray; 19: a manual paper supply tray; 21: an intermediate transfer belt; 22: a belt cleaning device; 23: a secondary transfer device; 23 a: a transfer roller; 24: a heating roller; 25: a pressure roller; 33: a pickup roller; 34: a positioning roller; 35: a conveying roller; 36a, 36 b: a discharge roller; 39a, 39 b: a discharge tray; 100: a control unit; 101: an image reading unit; 102: an image forming section; 103: a storage unit; 104: an image processing unit; 105: a communication unit; 106: a paper feeding section; 107: a panel unit; 108: a timing section; 109: an image density sensor; 110: a temperature and humidity sensor; 111: an original reading device; 112: an original conveying device; 1071: a display operation unit; 1072: a physical operation section; c: the direction of the arrow; k _ dvb, k _ ev, k _ ps, k _ ti, k _ us, kl _ x: a correction coefficient; LDP _ revise: correcting quantity; pa, Pb, Pc, Pd: an image station; r1: a paper conveying path; re _ mul: a basic correction amount; tend: a stop time; tpre: the current time.
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