JP2001183878A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which exactly regulates the image density relating to image formation even when the electrostatic charge characteristic of an image carrying member is fluctuated by preexposure. SOLUTION: A controller 101 built into the image forming device 100 sets the time when the power source of the image forming device 100 is turned on as integration start time and integrates the time when an exposure device 18 for discharge is actually lighted and emits light with respect to the time when the power source of the image forcing device is dropped or before the point of the time a sleep mode is started. The high voltage output value of the primary electrostatic charge bias in the formation of a reference batch pattern is changed in accordance with the integrated time by referencing the data on a dark attenuation rate table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image on a transfer material, and more particularly to an image forming apparatus having a function of controlling image density.

[0002]

2. Description of the Related Art FIG. 7 is a side sectional view schematically showing, as an example, a main internal structure of a conventional image forming apparatus.

As shown in FIG. 7, an image forming apparatus 200
Is a color copying machine (multicolor image forming apparatus) utilizing an electrophotographic process for forming a multicolor image on a sheet material (transfer material) via an intermediate transfer member.

In the image forming apparatus 200, a rotating drum type electrophotographic photosensitive member (hereinafter referred to as "photosensitive drum") 1 as an image carrier is arranged.
Is driven to rotate at a predetermined peripheral speed (process speed) in the direction of arrow R1. Then, on the rotating peripheral surface of the rotating drum 1, an image forming process using toners of a plurality of colors is repeatedly performed.

More specifically, first, the photosensitive drum 1 is moved by an arrow R
In the process of rotating in one direction, the rotating peripheral surface of the photosensitive drum 1 is charged to a predetermined polarity and a predetermined surface potential by a charging device (for example, a corona charger) 2.

Next, the charged photosensitive drum 1
Is subjected to image exposure by the exposure device 3 to form an electrostatic latent image corresponding to a first color separation image (for example, a magenta component image) of a target color image. Examples of the exposure device 3 include an imaging exposure optical system based on color separation of a color original image, and a scanning exposure optical system using a laser scanner that outputs a laser beam modulated in accordance with a time-series electric digital image signal of image information. Widely used.

Subsequently, the electrostatic latent image formed on the photosensitive drum 1 is subjected, for example, to a first developing device 41 (a magenta developing device) of the color developing device 4 to produce a magenta M toner (colored charge) of a first color. Particles).

An intermediate transfer member 50 is in contact with the image carrier 1. As the intermediate transfer member 50, a belt type is widely used in addition to the drum-shaped intermediate transfer member shown in FIG. The intermediate transfer member 50 has a medium resistance elastic layer 52 provided on a conductive substrate 51, and may further include a release layer on the surface layer. The intermediate transfer member 50 is driven to rotate at the same peripheral speed as the photosensitive drum 1 in the direction of arrow R2.
The first bias power supply 61 applies a toner charge polarity (minus in the present embodiment) of the formed toner image (hereinafter, referred to as a “toner image”) on the photosensitive drum 1 to the base 51.
The transfer bias of the opposite polarity (plus) is applied.

After the transfer of the first color magenta toner image formed and carried on the surface of the photosensitive drum 1, the surface of the photosensitive drum 1 is cleaned by the cleaning device 14. The cleaned surface of the photosensitive drum 1 is neutralized by the light emission of the second exposure device (exposure device for static elimination) 18, and the surface potential of the photosensitive drum surface is made uniform to prepare for the next step of image formation.

Subsequently, similarly to the above-described series of image forming processes for the magenta toner image, the photosensitive drum 1 is charged, an image exposure L corresponding to a second color component image (for example, a cyan component image), and a second developing device are formed. A series of operations such as development using cyan C toner of 42 (cyan developing device), transfer of the formed cyan toner image of the second color to the intermediate transfer member 50, and cleaning of the surface of the photosensitive drum 1 by the cleaning device 14 include: This will be executed as the next image forming step.

Further, in accordance with the same operation procedure, an image forming step for a third color component image (for example, a yellow component image) and an image forming step for a fourth color component (for example, a black component image) are also performed. Executed sequentially.

As described above, the four-color image forming / transfer process is executed as a series of operations, so that the four toner images (magenta, cyan, yellow, and black toner images) are formed on the outer surface of the intermediate transfer member 50. ) Are sequentially superimposed and transferred to form a composite color toner image (mirror image) corresponding to the target color image.

When the image forming / transfer process for the four colors is completed, the paper feed roller 10 is driven to rotate, so that one of the transfer materials (sheets) P stacked in the paper feed cassette 9 is separated and conveyed. Is done. The transfer material P is further fed through a registration roller pair 11 and a transfer guide 12 to a transfer unit including a transfer device (corona charger) 7 and an intermediate transfer body 50 at a predetermined timing, and is transferred onto the photosensitive drum 1. The developed toner image is transferred.

At the time of transferring the toner image, the third bias power supply 71 changes the toner charging polarity (minus in this example) and the transfer bias of the opposite polarity (plus) to the transfer device 7.
Is applied to

The transfer material P after the transfer is transferred to the transport guide 13.
Through the fixing device 15. Here, the toner image is subjected to a fixing process between the pressure roller 17 and the heated fixing roller 16 and is output as a final color image.

On the other hand, the intermediate transfer member 50 after the transfer of the toner image
Are cleaned by the cleaning device 8. The cleaning device 8 is a cleaning device for the intermediate transfer body 50 and is normally kept in a non-operating state with respect to the intermediate transfer body 50. However, when the transfer of the toner image onto the transfer material P is completed, the intermediate transfer body The outer surface of the intermediate transfer body 50 is cleaned by operating the cleaning device 8 on the outer surface of the intermediate transfer member 50.

Further, the above-mentioned image forming apparatus is provided with a so-called density control device for keeping the image density on the transfer material constant, and usually, the density control device changes the subtle color tone of the original image to the transfer material. So-called density control is performed so as to accurately reproduce the above.

As a control mode of the density control device, first, at a predetermined time (for example, when the image forming apparatus is started), a reference patch pattern (density detection patch) having a preset image density is used. More specifically, the image is formed on the intermediate transfer body in the same procedure as in the above-described series of image formation. Then, the optical reflection density of the patch pattern is read by using, for example, a density detection sensor (illustrated as an optical sensor S in FIG. 7) that is arranged to face the intermediate transfer member while maintaining a predetermined gap. The set density of the set patch pattern is compared with the measured density to determine the amount of deviation between the two. Then, it is presumed that a displacement equivalent to this also occurs in normal image formation, and according to the displacement amount,
Various conditions for obtaining a desired image density are corrected. Then, the various conditions after correction obtained in this way are used in normal image formation.

[0019]

Incidentally, in the image forming apparatus configured as described above, the photosensitive characteristics and charging characteristics of the photosensitive drum (organic photosensitive drum) tend to fluctuate in the charge removing step by the charge removing exposure device. .

This is because dark decay occurs on the surface of the photosensitive drum during a series of image forming operations such as charging, exposing, and developing, which are caused by the exposing action of the exposing device for static elimination. Under the influence of the dark decay, the surface potential of the photosensitive drum does not reach a desired set potential during exposure or development. Further, the degree of dark decay (dark decay rate) occurring on the surface of the photosensitive drum varies according to the total irradiation time of the exposure device for static elimination. This would cause a major problem for control.

Further, the charging characteristics and photosensitive characteristics of the photosensitive drum vary depending on changes in the use environment of the image forming apparatus such as temperature and humidity. This would further promote control problems.

As a result, the control accuracy of the density control is reduced, and the image quality is reduced.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for forming an image having a high image density even when the charging characteristic of an image carrier fluctuates due to pre-exposure. An object of the present invention is to provide an image forming apparatus that accurately performs the adjustment.

[0024]

In order to achieve the above object, the present invention comprises an image carrier for carrying an electrostatic latent image, a charging operation for charging the surface of the image carrier, and a charging operation for charging the surface of the image carrier. An exposure operation of irradiating light containing image information to the surface of the image carrier to form an electrostatic latent image; a developing operation of applying a developer to the electrostatic latent image to form a developer image; By performing a transfer operation to the transfer body of the agent image and a static elimination operation of irradiating the image carrier surface with light after the transfer operation as a series of image forming operations, image formation on the transfer body is repeated, Standard image forming means for performing a series of image forming operations on image information relating to a predetermined standard image, density detecting means for detecting the image density of the standard image obtained in the standard image forming operation, and the detected standard image Image density and
In the image forming apparatus, the control unit controls the series of image operation conditions based on the comparison with the image information on the standard image, and recognizes information on the irradiation time of light by the static elimination operation. A time recognition unit, and a correction unit that corrects at least one of the charging operation, the exposure operation, the development operation, and the transfer operation in the standard image forming operation based on information recognized by the time recognition unit. The gist is to provide

The control means may control at least an output voltage in the developing operation based on the comparison.

Further, the time recognizing means may be such that, after the start of the series of image forming operations, the irradiation time of light by the static elimination operation is integrated, and information on the integrated time is recognized.

The image processing apparatus may further include an operating environment detecting means for detecting an operating environment at the time of the image forming operation, wherein the correcting means includes information recognized by the time recognizing means and an operation at the time of the detected image forming operation. The operating condition of at least one of the charging operation, the exposure operation, the developing operation, and the transfer operation in the standard image forming operation may be corrected based on the environment.

Further, the operating environment at the time of the image forming operation may include information on at least one of temperature and humidity.

Further, the correction means may correct at least an output value of a voltage applied to the surface of the image carrier in the charging operation.

[0030] The information processing apparatus may further include storage means for storing in advance correction information of the operating condition corrected by the correction means as a numerical value corresponding to at least the information recognized by the time recognition means.

The correction information of the operating condition corrected by the correction means corresponds to at least the information recognized by the time recognition means and the operation environment at the time of the image forming operation detected by the operation environment detection means. It may be further provided with a storage means for storing in advance as a numerical value.

Further, the above-described series of image forming operations may be performed for each color of the developer of a plurality of colors to form an overlapped image of a plurality of colors on the transfer body.

According to the above configuration, the following control structure is realized.

(1) At the time of the density control performed under predetermined image forming conditions, the value of the potential fluctuation caused by the static elimination exposure operation is corrected, and the density control is performed under the adjusted image forming conditions.

(2) Correcting the amount of potential fluctuation due to the static elimination exposure operation according to the use environment of the image forming apparatus. That is, correction is performed according to the charging characteristics and photosensitive characteristics of the environment of the image carrier. For this purpose, for example, a dark decay rate table is held for each use environment, and an optimum image forming condition is calculated according to the use environment of the image forming apparatus.

With this control structure, for example, when controlling the density of the image forming apparatus, highly reliable density control can be performed by taking into account the characteristic of the dark decay rate of the photosensitive drum by the exposing device for static elimination.

The dark decay rate referred to here means that when the surface potential of the photosensitive drum reaches each point of the laser irradiation position and the developing position with respect to the charging position with respect to the high voltage output value of the primary charging bias. 3 shows the displacement rate of the surface potential at each position.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a side sectional view schematically showing a main internal structure of a multicolor image forming apparatus utilizing an electrophotographic process according to a first embodiment of the present invention.

The multi-color image forming apparatus (hereinafter, simply referred to as an image forming apparatus) 100 according to the present embodiment is the same as that shown in FIG.
The basic configuration is almost the same as that of the conventional image forming apparatus 200 described in (1). Further, based on basically the same image forming operation by each component, image formation on a transfer material and formation of a reference patch pattern on an intermediate transfer body are performed.

Therefore, the same reference numerals as those in FIG. 7 denote the same constituent members having the same structure and function, and a detailed description thereof will be omitted. Here, the density control of the image forming apparatus 100 will be described. The description will focus on the control procedure and mode.

The image forming apparatus 100 has a control device 101 built therein. The control device 101 includes a CPU, RA
M, ROM, timer for measuring time, etc., and an image forming apparatus 1 such as a photosensitive drum 1, an exposing device 3, an exposing device 18 for static elimination, a developing device 4, and an intermediate transfer body 50 by a bus (not shown)
A drive circuit (not shown) for driving the various constituent members of No. 00, a density detection sensor S, and the like are electrically connected. And
Based on the detection values of the density detection sensor and the like, the driving circuits of various constituent members are generally controlled, and the exposure time (irradiation time) of the charge removing exposure device 18 is measured.

The density detecting sensor S is a well-known optical sensor, and is disposed to face the intermediate transfer member 50 with a predetermined gap. The density detection sensor S has 96 light emitting sides and 96 light receiving sides.
It has a peak sensitivity wavelength at 0 (nm). Intermediate transfer member 50
Then, a plurality of density detection patches are formed under predetermined image forming conditions, and when the intermediate transfer body 50 rotates, these patches pass through a density detection sensor and correspond to the toner density of each patch. The density of each patch is calculated according to the output value of the light receiving sensor. From the calculated relationship between the toner density of each patch and the image forming condition, an image forming condition that provides the most satisfactory image is calculated. Here, the image forming condition refers to an image forming operation condition by each component of the image forming apparatus 100. In the present embodiment, the output voltage of the developing device 4 is applied to an image forming condition as a control gain for such density control.

FIG. 2 shows that the image density (the density detected by the density detection sensor S) of the reference patch pattern formed on the intermediate transfer member 50 is changed by changing the developing bias of the developing device 4.
It is a relationship diagram showing how it changes and the corresponding relationship.

Five density detection patches are formed for each color. As the image forming conditions for these five patches, the primary charging bias is fixed at -600 (∨), and the developing bias is set at -30.
The density is varied from 0 (∨) to −400 (∨) every −25 (∨), and set so that the density of each patch changes from the low density side to the high density side. Based on the relationship between the developing bias obtained under these conditions and the density of each patch, that is, the relationship shown in FIG. 2, a developing bias DB (Developing Bias) that gives a target density TD (Target Density) is calculated. In this embodiment, a halftone patch of image data 60 (%), which is optimal for image density stability and gradation stability, is used as a density detection patch, and TD is set to 1.0 for each color.
0 (optical density) was applied.

The density control is started at a preset timing, such as when starting the image forming apparatus or after forming a predetermined number of images. The calculation of the optimum developing bias is performed for each color.

Next, the image forming apparatus 100 of the present embodiment
In the following, the principle of the control (correction control) performed to suppress the variation in image density caused by the charge erasing operation will be described below.

The amount of change in the surface potential of the photosensitive drum 1 due to the charge erasing exposure operation changes depending on the exposure time of the charge erasing exposure. Is adjusted to increase the accuracy of the density control.

For example, FIG. 3 shows a temporal change (dark decay) of the potential of the photosensitive drum surface occurring during an image forming operation in a general image forming apparatus. More specifically, the surface potential at a predetermined position on the photosensitive drum 1 indicates the transition of the surface potential at each position when the laser irradiation (exposure) position reaches each point of the developing position with reference to the charging position.

As shown by the two-dot chain line in FIG. 3, when the charge eliminating exposure operation is not performed, the variation amount of the surface potential is small over a series of image forming operations.

However, as shown by the solid line in FIG. 3, in the image forming operation accompanied by the charge erasing exposure operation, the potential greatly fluctuates with the exposure irradiation.

The increase in the amount of potential fluctuation is caused when the predetermined point on the photosensitive drum 1 moves from the charging position to the laser irradiation position and further to the developing position after charging by the charging device 2. Greatly affects the amount of potential decay (the amount of potential decay relative to the moving distance).

FIG. 4 is a time chart showing the transition of the surface potential of the photosensitive drum 1 on the abscissa axis after the start of the image forming operation by the image forming apparatus 100 with the integrated irradiation time by the exposing device for static elimination as a horizontal axis. The surface potential of the photosensitive drum 1 shown on the vertical axis is at the developing site. Specifically, the surface of the photosensitive drum 1 is charged to a predetermined potential (−600 (∨)) by the charging device 2 with a constant charging bias. Thereafter, the same operation as in normal image formation is continuously performed, and at the same time, the surface of the photosensitive drum 1 is continuously irradiated by the exposure device 3.

As is apparent from FIG. 4, the potential displacement of the developing device 4 at the start due to dark decay was reduced by about 15 (∨), but the potential displacement increased during the exposure time (irradiation time). When the irradiation time reaches a certain level, the displacement is stable (the maximum potential displacement at a stable place is −70).
(∨) decline). The actual dark decay rate table is used for the operation rate of the image forming apparatus main body.

That is, the image forming apparatus does not always perform the image forming operation, and it is necessary to consider the time during which the exposure irradiation is not performed.

More specifically, the time when the power of the image forming apparatus is turned on is defined as the integration start time, and thereafter, when the power of the image forming apparatus is turned off or the time until the sleeve mode is entered, The time during which the charge removing exposure device 18 is actually turned on and irradiating light is integrated, and the ratio is fed back to the dark decay rate table.

Hereinafter, verification performed for the effect of the present embodiment will be described. As a verification method, 1000 sheets of continuous image formation were performed by the image forming apparatus of FIG. 1 (less than 3 hours).
This is performed continuously, and the difference in image quality between when the image forming condition is corrected according to the present embodiment and when the correction is not performed is compared.

Table 1 below shows the verification results of the first embodiment.

[0059]

[Table 1] It is assumed that the density control executed at a predetermined timing is executed after the power is turned on and every 500 sheets thereafter.

(1) In the case where potential correction was not performed After the image forming apparatus was started, the density control was properly performed during the initial period, and there was no problem in image quality. However, 50
After 0 sheets, characters and lines tended to be slightly thicker, and after 1000 sheets, characters and lines became further thicker. At the same time, ground force blurs began to occur. Thereafter, these tendencies only worsened, and after 3000 sheets, the density control was not sufficiently performed.

The causes will be described with reference to FIG.

FIG. 5 shows the unexposed portion potential (VD), the haze portion potential (VL), and the developing bias potential (Vdb) on the photosensitive drum surface for each patch. Here, the non-exposure / exposure means exposure exposed by a laser based on image data. Initially after the image forming apparatus is started, VD and VL are values indicated by solid lines. Under this condition, the developing bias is from -300 (∨) to -400.
It is controlled within the range of (∨). However, when the static elimination exposure operation is repeated, VD gradually decreases, and VL also slightly decreases accordingly (each value indicated by a broken line). If this potential drop is increased by dark decay, the potential difference (back contrast potential) between VD and Vdb becomes small, and ground fog occurs. This background fog also affects the patch density at the time of density control using a halftone patch, resulting in an error in calculating an optimum developing bias. Further, when the back contrast potential decreases, characters and lines tend to become thicker.

Further, since the fluctuation amount of VL is not so large relative to the fluctuation amount of VD, the potential difference between Vdb and VL (developing contrast: a value which determines the image density), that is, the image density does not largely change. For this reason, an optimum developing bias is generated in the density control, but a ground force blur occurs due to a small back contrast potential.

(2) In the case where potential correction is performed The potential fluctuation to the dotted line as shown in FIG. 5 is corrected by correcting the high voltage output of the primary charging during the density control, so that the potential on the surface of the photosensitive drum is fixed. -600 (∨). As a result, since the density control is periodically performed from the start of the image forming apparatus 100 to after the image formation of 3000 sheets, image defects such as occurrence of ground force blur, enlargement of characters and lines do not occur, and The effect of the invention was confirmed.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
This embodiment will be described focusing on the differences from the first embodiment.

According to the second embodiment, an image forming apparatus having substantially the same basic configuration and function as the first embodiment uses a well-known environment sensor (temperature / humidity sensor) for detecting environmental conditions. It is additionally provided. Further, the second embodiment is different from the first embodiment in that the control device holds a dark decay rate table for each use environment of the image forming apparatus and executes correction of image forming conditions according to the environment tables.

The classification of the environment table is set in advance and stored in the ROM or the like of the control device, and the operating environment of the image forming apparatus is identified based on the temperature data and humidity data detected by the temperature / humidity sensor. That is, the environment in which the temperature and humidity sensors are provided is classified into the following three environments (i), (ii), and (iii) based on the temperature data and the humidity data.

(I) Normal temperature and normal humidity corresponding to a normal office environment (corresponding to a temperature of 23 ° C. and 50% RH, hereinafter referred to as “NN environment”) (ii) Low temperature and low humidity corresponding to a winter environment (temperature of 15 ° C. and humidity of 10) % RH (hereinafter referred to as “LL environment”) (iii) High temperature and high humidity equivalent to summer environment (temperature 30 ° C. and humidity 80% RH, hereinafter referred to as “HH environment”)

FIG. 6 shows the dark decay characteristics due to each of the environments (i), (ii) and (iii), similarly to FIG. 4, and the transition of the surface potential of the photosensitive drum with the integrated irradiation time by the exposure apparatus for static elimination as the horizontal axis. As shown.

As can be seen from FIG. 6, the potential displacement due to dark decay occurs with the exposure irradiation time, and the amount of the displacement varies depending on the environment. The displacement is larger in the HH environment than in the LL environment. The displacement is large, and the maximum displacement is -50 in the LL environment.
In contrast to (−), -100 under HH environment
(∨). Using these characteristics, an environment table is created in consideration of environmental conditions, and verification is performed in each environment based on those tables in the same manner as the verification performed for the effect of the first embodiment. , Confirmed its effect.

The results are shown in Table 2 below (however, N
See Table 1 for N environments).

[0072]

[Table 2] (LL environment) Since the NN environment and the potential fluctuation curve are almost the same, the same environment table as the NN environment was used. Even when the primary charging bias is not corrected, the effect on the image quality is small because the potential variation is small originally.Thickness of characters and lines was seen after 2,000 sheets, and the ground force blur was seen. However, the ground force blur was slightly above the acceptable level.

On the other hand, it was confirmed that when the primary charging bias was corrected, such image defects did not occur. (HH environment)

Since the amount of potential fluctuation in the HH environment is extremely large, this is an environment in which the influence on the image quality appears most.

When the correction of the primary charging bias was not performed, the ground and image blur were already generated after 500 sheets, and the characters and lines were severely scattered with respect to the image quality after that, which greatly exceeded the allowable level. In addition, as a supplementary evaluation,
The image formation was paused for a while (up to 1 hour in 15-minute units), and the influence of the potential fluctuation was reduced to form an image at another value. The result was that yellowing began to occur.

On the other hand, by performing correction of the primary charging bias using the HH environment table, these image defects do not occur at all, and stable image quality can be maintained.

Incidentally, when the high voltage output of the primary charging bias after 3000 sheets after correction was measured, it was found to be -698
(∨) is shown. As is apparent from this result, in order to make the potential of the photoconductor surface in the developing device −600 (∨), the potential correction of −98 (∨) was actually performed.

As described above, according to the image forming apparatus of the present embodiment, by correcting the amount of potential fluctuation due to the charge removal exposure operation for each environment at the time of density control, the optimum image forming conditions according to the environment can be determined. It can be adopted, and it can continue to provide stable image quality.

In the above embodiments, the density detection position is not limited to the intermediate transfer member, but may be an image carrier such as a photosensitive member.

In each of the above embodiments, the time when the power of the image forming apparatus is turned on is defined as the integration start time.
When the power of the image forming apparatus is turned off or the time until the sleeve mode is entered, the time during which the charge removing exposure device 18 is actually turned on and the light is irradiated is integrated,
A control mode in which the ratio is fed back to the dark decay rate table is used. That is, here, the integrated value of the intermittent irradiation time of the exposing device 18 for static elimination is recognized as the light irradiation time.

On the other hand, the recognition of the light irradiation time by the charge removing exposure apparatus is not limited to the above.

For example, the time from when the power of the image forming apparatus is turned on is simply measured, and the entire operation time of the image forming apparatus may be used as the light irradiation time, or a predetermined ratio is added to the total operation time. The time may be set as the light irradiation time. The point is that if information relating to the irradiation time of light due to the static elimination operation of the static elimination device is reflected in the density control as one parameter with a numerical value that reflects in some form, an effect equivalent to or equivalent to that of the present embodiment is achieved. Can do it.

The object to be corrected by reflecting the information on the light irradiation time is not limited to the developing bias related to the density control, but may be other operating conditions related to the charging operation, the exposure operation, the developing operation and the transfer operation. Or a combination thereof.

In each of the above embodiments, the image forming apparatus of the present invention is applied to a multi-color image forming apparatus. However, the present invention is not limited to this. The present invention can be applied to an image forming apparatus.

[0085]

As described above, according to the present invention,
By correcting the operating conditions of the image forming apparatus at the time of density control according to the irradiation time of the exposure apparatus for static elimination, it is possible to avoid image quality deterioration such as thickening, scattering, and background fogging of lines.

Further, a correction table for the amount of potential fluctuation according to the environment in which the image forming apparatus is used is held for each environment, and the image forming conditions are corrected according to the environment table when controlling the density, so that it depends on the operating environment. Thus, a high-quality image can be stably provided without performing.

[Brief description of the drawings]

FIG. 1 is a side sectional view schematically showing a main internal structure of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a relationship diagram showing a correspondence relationship between an image density of a reference patch pattern and a developing bias of a developing device.

FIG. 3 is a time chart showing a temporal change in the potential of the photosensitive drum surface caused during the image forming operation due to the influence of the static elimination exposure.

FIG. 4 is a time chart showing changes in the surface potential of the photosensitive drum, with the integrated irradiation time by the exposure apparatus for static elimination as the horizontal axis.

FIG. 5 is a relationship diagram showing a correspondence relationship between a developing bias and a surface potential on a photosensitive drum.

FIG. 6 is a time chart showing changes in the surface potential of the photosensitive drum, with the integrated irradiation time by the exposure apparatus for static elimination as the horizontal axis.

FIG. 7 is a side sectional view schematically showing a main internal structure of a conventional image forming apparatus.

[Brief description of reference numerals]

 REFERENCE SIGNS LIST 1 photosensitive drum 2 charging device 3 exposure device 4 developing device 5 intermediate transfer member 7 transfer charging device 8 intermediate transfer member cleaning device 14 photoconductor cleaning device 15 fixing device 18 static elimination exposure device S density detection sensor

 ────────────────────────────────────────────────── ─── Continued on front page F term (reference) 2H027 DA09 DA11 DA14 DA39 DE02 DE10 EA01 EA02 EA03 EA05 EB04 EC03 EC06 ED24 ED26 EE02 EE08 EF06 FA28 2H035 AA10 AB03 2H073 AA02 BA02 BA13 BA28 BA33 CA22

Claims (9)

[Claims] An image bearing member for carrying an electrostatic latent image; a charging operation for charging the surface of the image bearing member; and irradiating the charged surface of the image bearing member with light containing image information for statically. An exposure operation for forming an electrostatic latent image, a developing operation of applying a developer to the electrostatic latent image to form a developer image, a transfer operation of the developer image to a transfer body, and the transfer operation after the transfer operation. By performing the static elimination operation of irradiating the surface of the image carrier with light as a series of image forming operations, image formation on the transfer body is repeated, and the series of image forming operations is performed on image information relating to a predetermined standard image. Image forming means, density detecting means for detecting the image density of the standard image obtained in the standard image forming operation, comparing the detected image density of the standard image with image information on the standard image, Based on the comparison, An image forming apparatus comprising: a control unit configured to control an image operation condition; a time recognizing unit that recognizes information on a light irradiation time by the static elimination operation; and the standard based on the information recognized by the time recognizing unit. The charging operation in the image forming operation, the exposure operation,
An image forming apparatus comprising: a correction unit configured to correct at least one operation condition of a developing operation and a transfer operation. 2. The image forming apparatus according to claim 1, wherein the control unit controls at least an output voltage in the developing operation based on the comparison. 3. The image forming apparatus according to claim 1, wherein said time recognizing means accumulates a light irradiation time by said static elimination operation after said series of image forming operations is started, and said accumulated time. An image forming apparatus comprising: 4. The image forming apparatus according to claim 1, further comprising an operating environment detecting unit configured to detect an operating environment at the time of the image forming operation, wherein the correcting unit is configured to detect the time. The charging operation in the standard image forming operation based on the information recognized by the recognition unit and the operating environment at the time of the detected image forming operation,
An image forming apparatus, wherein an operation condition of at least one of an exposure operation, a development operation, and a transfer operation is corrected. 5. The image forming apparatus according to claim 4, wherein the operating environment during the image forming operation includes information on at least one of temperature and humidity. 6. The image forming apparatus according to claim 1, wherein the correction unit corrects at least an output value of a voltage applied to the surface of the image carrier in the charging operation. An image forming apparatus comprising: 7. The image forming apparatus according to claim 1, wherein the correction information of the operating condition corrected by the correction unit corresponds to at least the information recognized by the time recognition unit. An image forming apparatus further comprising a storage unit that stores in advance a numerical value to be processed. 8. The image forming apparatus according to claim 4, wherein the correction information of the operating condition corrected by the correction unit is detected by at least the information recognized by the time recognition unit and the operation environment detection unit. An image forming apparatus further comprising a storage unit that stores in advance a numerical value corresponding to an operating environment at the time of an image forming operation. 9. The image forming apparatus according to claim 1, wherein the series of image forming operations are performed for each color of a plurality of color developers, so that a plurality of colors An image forming apparatus for forming an overlapped image.