JPH11119477A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make optimally adjustable the concentration by calculating a detected value aptitude curve, based on values detected with a photosensor, when an image pattern is formed on an image carrier and when an image is not formed and adjusting the concentration, to make it coincident with the curve. SOLUTION: The photosensor 70 is constituted of an LED and a photodiode for instance, the surface of a photoreceptor drum 1 is irradiated with the LED and the reflected light is detected by the photodiode, to amplify the detected output of the photodiode by a circuit, so that the output of the photosensor is obtained. A control part 71 receives the output of the photosensor 70 and executes control, to make the concentration of each toner optimum. Then, the detected value aptitude curve is calculated on the basis of the values detected by the photosensor 70, when the image pattern is formed on the drum 1 and when the image is not formed and the concn. is adjusted to coincide with the detected value aptitude curve.

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, and more particularly to an image density adjusting technique.

[0002]

2. Description of the Related Art By forming an image pattern on an image carrier and detecting the image pattern by an optical sensor,
2. Description of the Related Art An image forming apparatus for adjusting the density of an image formed on an image carrier is known. FIG. 11 is a diagram illustrating a configuration example of an image forming apparatus, and is a diagram illustrating a configuration example of a multicolor image batch transfer type color image forming apparatus. In FIG. 1, reference numeral 1 denotes a photosensitive drum serving as an image bearing member, which is formed by applying an OPC photosensitive member on the drum, is grounded in terms of potential, and is driven to rotate clockwise. Reference numeral 2 denotes a scorotron charger, which applies a uniform charge of the potential VH to the peripheral surface of the photosensitive drum 1 by corona discharge using a grid and a corona discharge wire held at the potential VG. Prior to charging by the scorotron charger 2, an exposing device (for example, PCL) using a light emitting diode or the like in order to eliminate the history of the photoconductor up to the previous print.
Exposure by 3 is performed to remove static electricity from the peripheral surface of the photoconductor.

After the photosensitive member is uniformly charged, an image exposure means 10
Performs image exposure based on the image signal. The image exposure means 10 uses a laser diode (not shown) as a light emitting light source, scans the optical path by bending a light path by a reflection mirror 12 via a rotating polygon mirror 11, an fθ lens and the like, and rotates the photosensitive drum 1 (sub-scan). Thus, an electrostatic latent image is formed. Here, the character portion is exposed to form a reversal latent image such that the character portion has a lower potential VL.

At the periphery of the photosensitive drum 1, yellow (Y), magenta (M), cyan (C), black (BK)
Developing devices 20 each containing a developer such as a toner and a carrier are provided. First, development of the first color is performed by a developing sleeve 21 which rotates while holding a developer with a built-in magnet. The developer consists of a carrier in which ferrite is used as a core and an insulating resin is coated around the core. The developer is regulated to a layer thickness (developer) of 100 μm to 600 μm on the developing sleeve 21 by the layer forming means, and is conveyed to the development area.

The gap between the developing sleeve 21 and the photosensitive drum 1 in the developing area is larger than the layer thickness (developer) by 0.2.
mm to 1.0 mm, during which an AC bias having a voltage value VAC and a DC bias having a voltage value VDC are applied in a superimposed manner. Since VDC, VH and the charge of the toner have the same polarity,
The toner that has been triggered to separate from the carrier by VAC does not adhere to the VH portion having a higher potential than VDC,
It adheres to the VL portion having a lower potential than VDC, and visualization (reversal development) is performed.

[0006] After the visualization of the first color is completed, the image forming process of the second color is started, the uniform charging is performed again by the scorotron charger 2, and the electrostatic latent image based on the image data of the second color is image-exposed. 10 formed. At this time, the charge elimination performed by the exposure device 3 in the first color image forming step is not performed because the toner attached to the first color image portion scatters due to a sharp drop in the surrounding potential.

[0007] Again, the same electrostatic latent image as that of the first color is formed on the portion of the photoconductor having the potential of VH over the entire surface of the photoconductor drum 1 where no image of the first color is formed. However, in the portion where the first color image is developed again, the toner adhered to the first color forms a light-shielding portion and the charge of the toner itself forms an electrostatic latent image of the potential VM, and the VDC and Development is performed according to the potential difference of VM. In the overlapping part of the first and second color images,
When the development of the first color is performed by forming an electrostatic latent image of VL, the balance between the first color and the second color is lost. Therefore, the exposure amount of the first color may be reduced to an intermediate potential such that VH>VM> VL. is there.

For the third and fourth colors, the same image forming process as that for the second color is performed, and a visible image of four colors is formed on the peripheral surface of the photosensitive drum 1. On the other hand, the recording paper P conveyed from the paper supply cassette 15 via the half-moon roller 16 temporarily stops, and when the transfer timing is adjusted, the paper supply roller 17
The paper is fed to the transfer area by the rotation of.

In the transfer area, a transfer roller 18 is pressed against the peripheral surface of the photosensitive drum 1 in synchronization with the transfer timing, and the fed recording paper P is sandwiched to transfer the multicolor image at once. Is done.

Next, the recording paper P is substantially neutralized by the separation brush 19 brought into a pressure contact state almost simultaneously, separated by the peripheral surface of the photosensitive drum 1 and conveyed to the fixing device 30, where the heat roller 31 and the pressure roller 32 are heated. After the toner is fused by pressurization, the toner is discharged to the outside of the apparatus via a paper discharge roller 41. The transfer roller 18 and the separation brush 1
Reference numeral 9 indicates that after the recording paper P has passed, the recording paper P is retracted from the peripheral surface of the photosensitive drum 1 to prepare for the formation of the next toner image.

On the other hand, the photosensitive drum 1 from which the recording paper P is separated
Removes and cleans the residual toner by pressing the blade 51 of the cleaning device 50, receives the charge removal by the exposure device 3 and the charge by the scorotron charger 2 again, and starts the next image forming process. The blade 51 moves immediately after the cleaning of the surface of the photoconductor and retreats from the peripheral surface of the photoconductor drum 1.

The image forming apparatus shown in FIG. 1 is capable of manual paper feeding in addition to the automatic paper feeding mechanism. The recording paper P manually fed by the manual paper feed table 60 is conveyed by the rotation of the pickup roller 61,
The sheet is fed to the transfer area through the same process as the sheet feeding from the sheet cassette 15 described above.

In the above-described density adjustment of the conventional apparatus, the surface of the image carrier when an image pattern is not formed is detected by an optical sensor, and a detection value appropriate curve is set based on the detected value, and the detected value appropriate curve is set. The concentration was adjusted to match.

FIG. 12 is a diagram showing the relationship between the toner adhesion amount and the output of the optical sensor. The vertical axis is the output of the optical sensor, and the horizontal axis is the toner adhesion amount. The point K0 in the figure indicates the output of the optical sensor when the toner adhesion amount is 0, that is, the reflection characteristic of the surface of the photosensitive drum 1 to which no toner is attached. f1 indicates Y (yellow) characteristics, f2 indicates M (magenta) characteristics, f3 indicates C (cyan) characteristics, and f4 indicates BK (black) characteristics. From the figure, it can be seen that the output of the optical sensor decreases as the toner adhesion amount increases, and when the toner adhesion amount exceeds a certain amount, the optical sensor output is saturated.

In the conventional apparatus, a detection value characteristic curve is assumed from the optical sensor output K0 when the toner adhesion amount is 0, and the density is adjusted to match the characteristic. FIG. 13 is a diagram showing the relationship between the toner adhesion amount and the sensor output. The case of Y as the toner will be described. When the output of the optical sensor at the time when the toner adhesion amount is 0 is shifted from the K0 point to the K1 point or the K2 point, the characteristic changes as indicated by f1a and f1b in the figure, and in the saturation region, the characteristic curve f1 It turns out that it becomes the same as

[0016]

Conventional density adjustment measures the output of an optical sensor when the toner adhesion amount is 0, and increases the amount of light emitted from the LED of the optical sensor when the output is not at the K0 point. We had to make adjustments by reducing it. When the output of the optical sensor is as low as the point K2 in the figure, when the output of the optical sensor at the time when the amount of toner adhered is 0 is brought to the point K0 with the light emission amount of the LED, the characteristic becomes as shown by f1 'in the figure. It shifts upward. Conversely, the output of the optical sensor is K in the figure.
When the point is as high as one point, if the output of the optical sensor when the amount of toner emitted is 0 and the amount of toner adhering to the LED is brought to the point K0, the characteristics thereof are shifted downward in the opposite direction, and the density cannot be accurately adjusted.

If an appropriate detection value curve is set based only on detection values when no image pattern is formed as in the conventional method, an erroneous detection due to a scratch on the image carrier or a developer remaining on the image carrier will occur. There is a possibility that an appropriate detection value curve is set based on the detected value. As a result, there is a problem that the density adjustment according to the characteristics of the image carrier is not performed, and good image formation cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and has as its object to provide an image forming apparatus capable of performing optimal density adjustment.

[0019]

[Means for Solving the Problems]

(1) The present invention for solving the above-mentioned problems includes an image carrier,
Developing means for visualizing the electrostatic latent image formed on the image carrier with a developer carried on a developing sleeve, and detecting the density of an image pattern formed on the image carrier by an optical sensor; And a density adjusting unit for performing density adjustment, wherein the detection value by the optical sensor when the image pattern is formed on the image carrier and the optical sensor when the image is not formed. A detection value appropriate curve is calculated based on the detection value, and the density adjustment of the image pattern is performed using the detection value appropriate curve.

According to the structure of the present invention, the detection value of the optical sensor when the image pattern is formed on the image carrier and the detection value of the optical sensor when no image is formed are based on the detected value. Since the detection value appropriate curve is calculated and the density can be adjusted to match the detection value characteristic curve,
Optimum density adjustment can be performed.

(2) In this case, the detection value of the optical sensor when the image pattern is formed on the image carrier is a detection value of the solid image pattern by the optical sensor. .

According to the configuration of the present invention, the detection value of the solid image pattern by the optical sensor can be used as data for obtaining a detection value appropriate curve. (3) Further, the density is adjusted by changing the rotation speed of the developing sleeve.

According to the configuration of the present invention, the density can be adjusted by adjusting the amount of toner supplied from the developing device by changing the rotation speed of the developing sleeve. (4) Further, the density is adjusted by changing the developer density in the developing means.

According to the structure of the present invention, the density can be adjusted by changing the density ratio of the developer (mixing ratio of toner and carrier). (5) Further, the density is adjusted by changing the AC bias voltage in the developing means.

According to the structure of the present invention, A
The density can be adjusted by changing the C bias voltage. (6) Further, the density is adjusted by changing the DC bias voltage in the developing means.

According to the structure of the present invention, D in the developing means is
The density can be adjusted by changing the C bias voltage. (7) In addition, the density is adjusted by changing the laser power as a means for exposing the photosensitive member to an image.

According to the configuration of the present invention, the density can be adjusted by changing the laser power as the image exposure means. (8) Further, the method is characterized in that the density adjustment is performed by changing the lighting time of a laser which is an image exposure means for the photoconductor.

According to the structure of the present invention, the density can be adjusted by changing the lighting time of the laser as the image exposure means. (9) Further, the present invention is characterized in that the density is adjusted by changing the charging potential of the photoconductor.

According to the configuration of the present invention, the density can be adjusted by changing the charging potential to the photosensitive member. (10) Further, the density adjustment is performed every predetermined number of prints.

According to the configuration of the present invention, if the number of prints used increases, the toner density adjustment is deviated. Therefore, by performing the density adjustment again, an appropriate development density can be obtained.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the present invention. The same components as those in FIG. 11 are denoted by the same reference numerals. In the figure, reference numeral 70 denotes an optical sensor provided in the vicinity of the image carrier (photosensitive drum) 1, and is constituted by, for example, an LED and a photodiode. By irradiating the surface of the photosensitive drum with the LED, the reflected light is detected by a photodiode, and the output of the detected photodiode is amplified by a circuit, whereby an optical sensor output can be obtained.

Reference numeral 71 denotes a control unit that receives the output of the optical sensor 70. The control unit 71 receives the output of the optical sensor 70 and controls the toner so that the density of each toner becomes optimal (described later in detail). Reference numeral 72 denotes a memory connected to the control unit 71 for storing measured values and the like. As the control unit 71, an overall control unit that controls the entire image forming apparatus may be used, or a separate control unit such as a CPU may be used for density control. Reference numeral 73 denotes an L detection unit that detects the developer density ratio of the developing device 20, and the output thereof is input to the control unit 71. A control signal is supplied from the control unit 71 to the developing sleeve 21, and toner supply control is performed by adjusting the rotation of the developing sleeve. The operation of the device configured as described above will be described below.

FIG. 2 is a flowchart showing the overall operation of the present invention. First, a drum status check is performed (S1). This drum status check corresponds to the initialization of the apparatus. Next, a developer status check is performed (S2). This developing unit status check is for checking whether or not the developing unit 20 is in an appropriate state. Next, the number of prints of the apparatus is checked (S3).

The apparatus determines from the above checks whether it is time to adjust the toner density (S4). In the figure, the toner density adjustment is represented by whether patch measurement is necessary. If the toner density adjustment is necessary, a patch measurement sequence (details will be described later), which is a point of the present invention, is performed (S5). When the above preprocessing is completed, a normal printing operation is performed (S
6). When the normal operation is completed, the process returns to step S1 to check whether or not the toner density adjustment is necessary. The above sequence is repeated.

FIG. 3 is a flowchart showing a patch measurement sequence (step S5 in FIG. 2). First, the output of the optical sensor in a state where the toner does not adhere to the photosensitive drum 1 is measured (S1; details will be described later). This measurement is shown in FIG.
This corresponds to the process of measuring the K0 point in the characteristic No. 2.

When the photoconductor measurement is completed, a color selection operation is started (S2). In the case of a color image forming apparatus, there are four types of toners, Y (yellow), M (magenta), C (cyan), and BK (black). Therefore, the following processing is repeated for each color. .

When the color selection is completed, the output of the L detection section 73 is received, and the L detection value of the developing device 20 for the color is confirmed (S3). The L detection value is a mixing ratio (developer) of the toner and the carrier in the developing device, and checks whether the L detection value is within an appropriate range. If the L detection value is NG, a prescribed process for returning the L detection value to the normal range is performed (S4).

Next, a solid patch measurement is performed (S5).
In this solid patch measurement, the output of the optical sensor is read in a state where a sufficient amount of toner is attached to the photosensitive drum 1. FIG. 4 is an explanatory diagram of the adhesion of the solid toner. Four types of toner patches 75 of Y, M, C, and BK are formed along the peripheral surface of the photosensitive drum 1. Light is emitted from the LED 70a constituting the optical sensor 70 to the toner patch 75 and the reflected light is received by the photodiode 70b. By this solid patch measurement, the point P1 (in the case of Y) in the characteristic of FIG. 12 is measured.

When the measurement of the solid patch is completed, the control patch is measured (S6). In this control patch measurement, a small amount of non-solid toner is attached to the surface of the photosensitive drum 1 to measure the output of the optical sensor. By this control patch measurement, the P2 point (in the case of Y) in the characteristic of FIG. 12 is measured.

By the above processing, the optical sensor output K0 when the toner adhesion amount is 0 and the optical sensor output P1 in the case of the solid patch are obtained. When K0 and P1 are obtained, a characteristic curve as shown in FIG. 12 can be estimated. The measurement of the optical sensor output P2 in the control patch measurement is to measure the output of the halftone optical sensor. These three points K0, P
The optical sensor outputs at 1 and P2 are stored in the memory 72. By measuring these three points, the toner adhesion amount in the halftone can be obtained by calculation according to a formula described later.

Based on the above measurement, feedback is given to the image forming processor so as to obtain an optimum toner adhesion amount. Specifically, the toner density is adjusted by adjusting the rotation amount of the developing sleeve 21. Therefore,
Calculate the developing sleeve rotation speed to obtain the optimum density (S
7). The above processing is performed for each of the Y, M, C, and BK toners. It is checked whether or not the processing has been completed for all the toners (S8). If the processing has not been completed, the process returns to step S2, and the processing for the other toners is repeated. When the processing for all the toners ends, the processing ends.

FIGS. 5 and 6 are flowcharts showing the photoconductor measurement processing operation (step S1 in FIG. 3). This process measures the output of the optical sensor in a state where the toner is not attached to the image carrier (photosensitive drum) 1. First, a cleaner (blade 51 in FIG. 1) is pressed against the surface of the photosensitive drum (S1), and the photosensitive drum 1 is rotated (S1).
2). As a result, the residual toner adhering to the surface of the photosensitive drum is scraped and removed. The apparatus checks whether the cleaning is OK (S3). If not, the process returns to step S2, and the photosensitive drum 1 is rotated.

When the cleaning of the photosensitive drum surface is completed, a control signal for causing the LED 70a of the optical sensor 70 to emit light is output (S4). Specifically, control is performed so that the optical sensor output becomes 8V.

Therefore, the controller 71 checks whether the LED output is adjustable (S5). If the adjustment is not possible, a warning is issued (S6). If adjustable,
The output of the optical sensor is captured (S7). At this time, it is checked whether the output of the optical sensor is within about 8V ± 0.1V (S8). If not, the LED control signal is adjusted (S10), and the process returns to step S5 again. If so, it is checked whether the output of the optical sensor is within 8V ± 0.5V (S9). If not, the process returns to step S10 to change the LED control signal.

If it is, the control section 71 takes in the output of the optical sensor (S11). The optical sensor 70 is
The point is sampled, and the average of the sampled value is Rd
(AV), the variation is set to Rd (DV) (S12). Next, it is checked whether the variation Rd (DV) is within 0.1 times the average value Rd (AV) (S13).
If not, a warning is issued (S14).

FIG. 7 shows a solid patch measurement sequence in the patch measurement sequence shown in FIG. 3 (step S5 in FIG. 3).
It is a flowchart which shows. First, a solid patch is formed on the photosensitive drum 1 as shown in FIG. 4 (S1). In this state, a specific solid patch 75 is irradiated with light by the optical sensor 70, and the control unit 71 converts the reflected light into an electric signal by the photodiode 70b, captures the amplified signal as a detection signal, and stores it in the memory 72. (S2).

Usually, about 10 patches 75 are sampled. The average value of the detection signals at this time is Rb (AV), and the variation is Rb (DV) (S2). The control unit 71 performs the average value calculation and the measurement of the variation. Next, the control unit 71
Compares the magnitudes of Rb (DV) and 0.1 times Rb (AV) (S4). If the variation is larger, a warning is issued (S5). If the variation is large, accurate density adjustment cannot be performed. If the variation is smaller, the process ends. The solid patch measurement described above is repeated four times, which is the number of toners Y, M, C, and BK.

Thus, the detection value of the solid image pattern by the optical sensor 70 can be used as data for obtaining a detection value appropriate curve. FIG. 8 is a flowchart showing an example of the control patch measurement sequence (Step S6 in FIG. 3). First, a halftone toner is attached to a patch formed on the surface of the photosensitive drum 1, and the reflected light is detected by an optical sensor (S1). The control unit 71 takes in the detected output of the optical sensor and stores it in the memory 72 (S2).
The measurement is performed by sampling about 10 points of the same patch. The average value at this time is Rc (AV), and the variation is Rc (D
V) (S3).

Here, the control unit 71 determines the variation Rc (D
The magnitude relationship between V) and 0.1 times the average value Rc (AV) is compared (S4). If the comparison shows that the variation is large, a warning is issued (S5). If the variation is not large, the process ends.

FIG. 9 is a flow chart showing the operation of the developing sleeve rotational speed calculation processing (step S7 in FIG. 3).
First, the control unit 71 reads out each measured value stored in the memory 72, and calculates the toner adhesion amount V of the control patch by the following equation.
Is calculated (S1).

[0051]

(Equation 1)

Where Rc is the output value of the halftone light sensor,
Rb is a solid patch optical sensor output, Rd is an optical sensor output on the surface of the photosensitive drum 1, and k is a constant. When the toner adhesion amount of the control patch is obtained in this way, the control unit 71 calculates the rotation speed of the developing sleeve 21 that gives an appropriate toner adhesion amount from the obtained toner adhesion amount (S2). Memory 72
Stored in advance is a table showing the relationship between the amount of adhered toner and the number of rotations of the developing sleeve 21 that gives an appropriate development density. Therefore, the control unit 71 accesses the table using the toner adhesion amount as an address and calculates the corresponding rotation number of the developing sleeve.

As described above, according to the present invention, the density can be adjusted by changing the rotation speed of the developing sleeve 21 to adjust the amount of toner supplied from the developing device 20.

The toner density can also be adjusted by detecting the developer from the L detector 73 provided in the developing device 20 and changing the developer density (mixing ratio of carrier and toner). According to this, the density can be adjusted by changing the density ratio of the developer.

FIG. 10 is a flowchart showing the warning process. When a warning is issued, first, a warning generation sequence is stored in the memory 72 (S1), read out when necessary, and "P" indicating a warning is displayed on the display unit (S1).
2). The operator can recognize that the development density adjustment has not been performed properly by looking at the "P" display.

The cycle for performing the density adjustment according to the present invention can be arbitrarily determined, and the index can be determined, for example, to be performed every 2,000 prints. The control unit 71 can perform the patch processing sequence shown in FIG. 3 every time the number of prints reaches 2000. If the number of prints used increases, the density adjustment becomes erratic, so by performing the density adjustment again,
An appropriate development density can be obtained.

In the above-described embodiment, the case where the rotational speed of the sleeve is changed and the case where the developer concentration is changed are described as the density adjustment method. However, the present invention is not limited to this, and the concentration can be changed by the following method. The AC bias voltage in the developing means is changed. The DC bias voltage in the developing means is changed. The laser power as an image exposure means for the photoconductor is changed. The lighting time of a laser as an image exposure means for the photoconductor is changed. The charge potential to the photoconductor is changed.

In the above embodiment, the case where the present invention is applied to a color image forming apparatus has been described. However, the present invention is not limited to this, and is similarly applied to a black toner single color image forming apparatus. be able to.

[0059]

As described above in detail, according to the present invention, there are provided: (1) an image carrier, and a developer in which an electrostatic latent image formed on the image carrier is carried on a developing sleeve. An image forming apparatus comprising: a developing unit that visualizes the image by a sensor; and a density adjusting unit that detects the density of an image pattern formed on the image carrier by an optical sensor and performs density adjustment. A detection value proper curve is calculated based on a detection value by the optical sensor when an image pattern is formed, and a detection value by the light sensor when an image is not formed, and the detection value proper curve is used. By performing the density adjustment of the image pattern, the detection value by the optical sensor when the image pattern is formed on the image carrier, and the detection value by the optical sensor when the image is not formed Based on detection value appropriate curve Can be calculated and the density can be adjusted to match the detected value characteristic curve, so that the optimum density adjustment can be performed.

(2) In this case, the detection value of the light sensor when the image pattern is formed on the image carrier is the detection value of the solid image pattern by the light sensor, and The detection value of the pattern by the optical sensor can be used as data for obtaining a detection value appropriate curve.

(3) By changing the number of revolutions of the developing sleeve, the number of toners supplied from the developing device can be adjusted by changing the number of revolutions of the developing sleeve, thereby adjusting the density.

(4) Further, by changing the developer concentration in the developing means, the concentration can be adjusted by changing the developer concentration ratio (mixing ratio of toner and carrier).

(5) By changing the AC bias voltage in the developing means, the density can be adjusted by changing the AC bias voltage in the developing means. (6) Further, by changing the DC bias voltage in the developing means, the density can be adjusted by changing the DC bias voltage in the developing means.

(7) Further, by changing the laser power as the image exposure means for the photosensitive member, the density can be adjusted by changing the laser power as the image exposure means.

(8) The density can be adjusted by changing the lighting time of the laser as the image exposure means by changing the lighting time of the laser as the image exposure means on the photosensitive member.

(9) Further, by changing the charging potential of the photosensitive member, the density can be adjusted by changing the charging potential of the photosensitive member. (10) Further, the density adjustment is performed for each predetermined number of prints, so that when the number of prints used increases, the toner density adjustment goes wrong. Therefore, the density adjustment is performed again to obtain an appropriate development density. .

As described above, according to the present invention, it is possible to provide an image forming apparatus capable of performing optimal density adjustment.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the overall operation of the present invention.

FIG. 3 is a flowchart illustrating a patch measurement sequence.

FIG. 4 is an explanatory diagram of solid toner adhesion.

FIG. 5 is a flowchart illustrating a photoconductor measurement processing operation.

FIG. 6 is a flowchart illustrating a photoconductor measurement processing operation.

FIG. 7 is a flowchart showing a solid patch measurement sequence.

FIG. 8 is a flowchart showing a control patch measurement sequence.

FIG. 9 is a flowchart illustrating a developing sleeve rotation speed calculating operation.

FIG. 10 is a flowchart illustrating a warning process.

FIG. 11 is a diagram illustrating a configuration example of a conventional device.

FIG. 12 is a diagram illustrating a relationship between a toner adhesion amount and a sensor output.

FIG. 13 is a diagram illustrating a relationship between a toner adhesion amount and a sensor output.

[Explanation of symbols]

 Reference Signs List 1 photoreceptor drum 20 developing device 21 developing sleeve 70 optical sensor 71 control unit 72 memory 73 L detection unit

Claims (10)

[Claims] An image bearing member; developing means for developing an electrostatic latent image formed on the image bearing member by a developer carried on a developing sleeve; and an image formed on the image bearing member. An image forming apparatus comprising: a density adjusting unit that detects the density of a pattern with an optical sensor and performs density adjustment; and a detection value obtained by the optical sensor when the image pattern is formed on an image carrier, and an image. An image forming apparatus comprising: calculating a detection value appropriate curve based on a detection value of the optical sensor when the image pattern is not formed; and adjusting the density of the image pattern using the detection value appropriate curve. 2. The value detected by the optical sensor when the image pattern is formed on the image carrier is a value detected by the optical sensor in a solid image pattern. Image forming device. 3. The density adjustment is performed by changing the number of revolutions of the developing sleeve.
An image forming apparatus according to claim 2. 4. The image forming apparatus according to claim 1, wherein the density adjustment is performed by changing a developer density in the developing unit. 5. The image forming apparatus according to claim 1, wherein the density adjustment is performed by changing an AC bias voltage in the developing unit. 6. The image forming apparatus according to claim 1, wherein the density adjustment is performed by changing a DC bias voltage in the developing unit. 7. The image forming apparatus according to claim 1, wherein the density is adjusted by changing a laser power serving as an image exposing means for the photosensitive member. 8. The image forming apparatus according to claim 1, wherein the density adjustment is performed by changing a lighting time of a laser serving as an image exposing means on the photosensitive member. 9. The method according to claim 1, wherein the density is adjusted by changing a charging potential of the photosensitive member.
The image forming apparatus according to any one of the above. 10. The image forming apparatus according to claim 1, wherein the density adjustment is performed for each predetermined number of prints.