JP2008076576A - Image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus configured to have proper image density with respect to density variations caused by the shaking of components and developing gap variations, a process cartridge, and a replacement kit. <P>SOLUTION: The image forming apparatus comprises an image forming apparatus 1 main body; the process cartridge which has an image carrier capable of carrying an electrostatic latent image, a developing roller 24 which supplies toner to the electrostatic latent image forming on the image carrier to form a toner image, and is configured to be attachable to and detachable from the image forming apparatus 1 body; a driving source 61 which drives the developing roller 24; a transfer device which transfers the toner image to a transfer material; and a fixing device which fixes the transferred toner image on the transfer material. The image forming apparatus 1 is further equipped with a density variation control means 62 for issuing a rotation pulse command with respect to the driving source 61, based on the density variation information on the developed toner image to perform control so that density variation of one rotation of the developing roller is held constant. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a process cartridge including a developing device that develops a latent image formed on an image carrier with toner, and an image forming apparatus including the process cartridge.

2. Description of the Related Art Conventionally, as an example of a developing device, a developing roller having a magnet having a plurality of fixed magnetic poles and a cylindrical developing sleeve surrounding the magnet is provided, and the outer peripheral surface of the developing sleeve is connected to the outer peripheral surface of the photoreceptor and a constant developing gap. And a developing device in which a developing roller is rotated around a center line is known.
In such a developing device, the rising of the developer (however, a two-component developer having a magnetic carrier and toner) along the magnetic field lines of the magnetic field generated by the magnet occurs on the outer peripheral surface of the developing sleeve. In the spiked developer, charged toner adheres to the magnetic carrier related to the spike.
Then, the toner in the spiked developer is transferred to the surface of the photoreceptor at a position facing the photoreceptor, so that the toner adheres to the electrostatic latent image formed on the surface of the photoreceptor and the toner image is formed. It is formed.
The magnet includes a plurality of magnetic poles, and the magnets forming the respective magnetic poles are formed in a bar shape or the like. In particular, the developing main surface has a developing main magnetic pole for raising the developer in the developing region portion of the developing sleeve surface. By rotating at least one of the developing sleeve and the magnet, the developer that is raised on the surface of the developing sleeve moves.

FIG. 10 is a schematic view showing a conventional developing roller. FIG. 11 is a schematic view of a developing device provided with this developing roller. 10 and 11 showing an example of the configuration of the conventional developing roller and developing device, the developing roller 100 includes a cylindrical developing sleeve 102 and flanges 103 fixed to both ends thereof.
Inside the developing sleeve 102, a magnet 101 is provided as a magnetic field generating means, and the developing roller 100 is supported so as to be rotatable around a center line. The developing roller 100 is disposed in the vicinity of the developer regulating blade 104 and the photoreceptor 105 (FIG. 10).
As described above, since the developing roller 100 is disposed in the vicinity of the developer regulating blade 104 and the photosensitive member 105, if the developing sleeve 102 is shaken, the developing roller 100 is located between the developer regulating blade 104 or the photosensitive member 105. The gap varies with the rotation period of the developing sleeve 102.

As a result, unevenness in the amount of developer carried on the developing roller 100 and unevenness in developing ability occur, and as a result, the toner image formed on the photoconductor 105 has uneven density at a pitch corresponding to the shake of the developing sleeve 102. Will occur. Therefore, in order to obtain high image quality, it is necessary to increase the deflection accuracy of the developing sleeve 102.
The density unevenness is caused by a change in the gap (development gap) between the developing sleeve 102 and the photosensitive member 105 or a speed change. Specifically, in the developing process, the toner in the two-component developer on the developing sleeve 102 is detached from the magnetic carrier and transferred onto the electrostatic latent image on the photoreceptor 105.
At this time, it is desirable for the developing sleeve 102 to rotate at a constant speed while maintaining a constant developing gap with the photosensitive member 105, but the developing gap slightly fluctuates due to the influence of the shaking of the developing sleeve 102. This variation changes the amount of toner adhering to the electrostatic latent image formed on the photosensitive member 105 and causes density unevenness to appear.

Particularly in recent years, the development gap tends to be narrowed as the image quality is improved. As the development gap becomes narrower, density unevenness due to fluctuations in the development gap or speed fluctuations becomes more prominent. Therefore, fluctuations in the development gap or speed fluctuations cannot be ignored. Various techniques have been proposed as countermeasures against such inconvenience (see, for example, Patent Documents 1 to 4).
Patent Document 1 discloses a technique for detecting the image patch density and controlling the speed of the developing roller. Japanese Patent Application Laid-Open No. H10-228561 discloses a color image forming apparatus that detects the image patch density and controls the speed of the developing roller. Further, Patent Document 3 discloses a technique that uses a stepping motor for driving the developing device, and Patent Document 4 discloses a technique that uses the same sensor for detecting a positional deviation and a density adjustment mark.
JP 2002-062727 A JP 2002-116586 A Japanese Patent Application Laid-Open No. 06-076960 JP 2001-166553 A

However, there is a limit to improving the accuracy of parts to increase the runout accuracy of the developing sleeve, which can not be ignored in order to obtain high image quality, and to suppress fluctuations in development gaps or speed fluctuations. This leads to an increase in the cost of the entire image forming apparatus.
Accordingly, an object of the present invention is to extract the density fluctuation component of one rotation cycle of the developing sleeve with respect to the density fluctuation caused by the component shake and the development gap fluctuation in consideration of the above situation, and further, the phase and amplitude. The development drive motor is feedback-controlled with a correction pulse that obtains rotation of the development sleeve so that the density fluctuation is kept constant with respect to the development drive motor that rotates the development sleeve with respect to the density fluctuation. Another object of the present invention is to provide an image forming apparatus having a configuration capable of obtaining an appropriate image density.

In order to solve the above-mentioned problems, an invention according to claim 1 is directed to an image forming apparatus main body, an image carrier capable of carrying an electrostatic latent image, and an electrostatic latent image formed on the image carrier. In the image forming apparatus comprising a developing roller for supplying toner to the toner image and developing the toner image, and a driving source for driving the developing roller, the driving source is controlled based on density fluctuation information of the developed toner image. The image forming apparatus includes a density fluctuation control unit that gives a rotation pulse command to the developer roller so as to keep the density fluctuation of one rotation of the developing roller constant.
According to a second aspect of the present invention, the density variation control means includes a pattern detection means for detecting the density of the test toner pattern transferred to the transfer material carrier after being formed on the image carrier, and a plurality of continuous detections. Based on the calculation results of the calculation means for extracting the density fluctuation component generated in the cycle of the developing roller from the density of the test toner patterns and obtaining the phase value and amplitude value of the density fluctuation period. Calculating means for calculating a displacement target setting pulse for displacing the rotation speed of the developing roller to a rotation speed that cancels the density fluctuation period, and the driving source of the developing roller is used as the displacement target setting pulse. The image forming apparatus according to claim 1, wherein feedback control is performed according to the above.

According to a third aspect of the present invention, there is provided a rotating body that transmits driving of the driving source to the developing roller, a reference mark that serves as a reference for the rotational position of the rotating body, and a reference mark detection that detects the reference mark. And an image forming apparatus according to claim 1 or 2.
According to a fourth aspect of the present invention, the timing for calculating the displacement target setting pulse is a timing at which a unit including the developing roller is replaced. It is characterized by.
According to a fifth aspect of the present invention, the apparatus main body includes the reference mark and the reference mark detection means, and the timing for calculating the displacement target setting pulse is determined when the cover provided in the apparatus main body is opened or closed. 4. The image forming apparatus according to claim 1, wherein the timing is timing.
According to a sixth aspect of the present invention, there is provided an image carrier that can carry an electrostatic latent image, and a developing roller that supplies toner to the electrostatic latent image formed on the image carrier and develops the toner image. And a process cartridge that is configured to be detachable from the image forming apparatus main body, and includes a rotating body that transmits at least driving of a driving source provided in the image forming apparatus main body to the developing roller. Features a cartridge.

According to a seventh aspect of the present invention, there is provided the process cartridge according to the sixth aspect, further comprising a recording medium that stores the circumferential phase and the amplitude value of the rotating body.
According to an eighth aspect of the invention, there is provided a process cartridge according to the seventh aspect, wherein the recording medium is read by a storage medium reading device provided on the image forming apparatus main body side.
According to a ninth aspect of the present invention, there is provided an image forming apparatus including a plurality of process cartridges according to any one of the sixth to eighth aspects.
According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, the developing roller in each toner cartridge can be driven independently.
According to an eleventh aspect of the present invention, in the image forming apparatus according to the ninth or tenth aspect, the pattern detecting unit detects a density of the test toner pattern and detects a position for aligning a color image. It is characterized by.

  According to the present invention, as described in the embodiment, it is possible to stabilize the concentration fluctuation irrespective of the component accuracy of the developing sleeve, and it is not necessary to increase the accuracy of the component, and the cost of the component is not increased. Therefore, it is possible to provide an image forming apparatus which can reduce the overall cost and obtain a good image quality.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram illustrating a color printer which is an example of an image forming apparatus. The operation of the color printer will be described with reference to FIG.
In the main body of the image forming apparatus (color printer) 1, four image carriers 2Y, 2M, 2C and 2BK configured as drum-shaped photoconductors are arranged along a transfer material conveyance direction A1 to be described later. Yes.
In the illustrated embodiment, a yellow toner image is formed on the surface of the image carrier 2Y on the most upstream side in the transfer material transport direction A1, and a magenta toner image is formed on the surface of the next image carrier 2M.

Further, a cyan toner image is formed on the surface of the next image carrier 2C, and a black toner image is formed on the surface of the next image carrier 2BK. These image carriers 2Y, 2M 2C and 2BK are each driven to rotate in the direction of arrow B1.
A transfer material transport device 3 is disposed opposite to the image carriers 2Y, 2M, 2C, and 2BK. The transfer material transport device 3 includes support rollers 4, 5, 6, and 7 and support rollers 4, 5, and 6 thereof. , 7 and a transfer belt 8 comprising an endless belt wound around the transfer belt 7. The transfer belt 8 is rotationally driven in the transfer material conveying direction A1.
Each image carrier 2Y, 2M, 2C, 2BK is in contact with the surface of the transfer belt 8, and at a position facing each image carrier 2Y, 2M, 2C, 2BK across the transfer belt 8, Transfer brushes 9Y, 9M, 9C, and 9BK, which are examples of the transfer device, are respectively disposed.

On the other hand, a sheet feeding cassette 11 of the sheet feeding apparatus 10 is disposed in the lower part of the main body of the image forming apparatus 1, and a transfer material made of transfer paper, for example, is placed on a bottom plate 12 disposed in the sheet feeding cassette 11. S is loaded.
When the feeding roller 13 in contact with the upper surface of the uppermost transfer material S is rotationally driven counterclockwise, the uppermost transfer material S is fed in the direction of arrow C, and the fed transfer. The material S is fed toward the transfer portion between the image carriers 2Y, 2M, 2C, and 2BK and the transfer belt 8 at a predetermined timing by the rotation of the registration roller pair 14.
Here, as described above, a yellow toner image is formed on the surface of the image carrier 2Y for yellow, and when the transfer material S passes through the transfer portion between the image carrier 2Y and the transfer belt 8, The yellow toner image formed on the surface of the image carrier 2Y is transferred onto the surface of the transfer material S by the action of the transfer brush 9Y.

The transfer material S successively passes through the transfer portions between the magenta image carrier 2M, the cyan image carrier 2C, the black image carrier 2BK, and the transfer belt 8, and each transfer brush 9M, By the action of 9C and 9BK, the toner images of the respective colors on the image carriers 2M, 2C, and 2BK are sequentially transferred while being superimposed on the yellow toner image that has already been transferred onto the transfer material S.
The transfer material S on which the four-color superimposed toner image is transferred onto the surface as described above passes between the fixing roller 15 and the pressure roller 16, and at this time, the toner image is formed by the action of heat and pressure. It is fixed on the surface of the transfer material S. Next, the transfer material S is stacked on the paper discharge tray 17 as indicated by an arrow E.
Each image carrier 2Y, 2M, 2C, 2BK and each element necessary for forming a toner image on the surface thereof are configured as an integral process cartridge 18Y, 18M, 18C, 18BK, respectively.
Since the configuration of each of these process cartridges 18Y, 18M, 18C, and 18BK is substantially the same, only the configuration and operation of the process cartridge 18Y having one yellow image carrier 2Y will be described with reference to FIG. I will explain.

FIG. 2 is a sectional view showing the structure of a process cartridge having a yellow image carrier. As shown in FIG. 2, the image carrier 2Y of the process cartridge 18Y is rotatably attached to the unit case 19 and is driven to rotate in the direction of arrow B1.
A charging roller 20 rotatably supported on the unit case 19 is in contact with the surface of the image carrier 2Y while rotating, and the surface of the image carrier 2Y is charged to a predetermined polarity by the charging roller 20.
On the other hand, in the main body of the image forming apparatus 1, as shown in FIG. 1, a laser writing unit 21 is arranged separately from the process cartridge 18Y, and the light modulated laser beam L emitted from the laser writing unit 21 As shown in FIG. 2, the surface of the charged image carrier 2Y is exposed, whereby an electrostatic latent image for a yellow image is formed on the surface of the image carrier 2Y.

The electrostatic latent image formed on the surface of the image carrier 2Y is visualized as a yellow toner image by the developing device 22. The developing device 22 includes a developing case 23 constituted by a part of the unit case 19 and a developing roller 24 that is rotatably supported by the developing case 23 and is driven to rotate counterclockwise. 23 stores a powdery two-component developer DY having a yellow toner and a carrier.
The developer DY is carried on the developing roller 24 and conveyed, and the amount of the developer DY is regulated by the regulating blade 26 and is carried to the developing region between the developing roller 24 and the image carrier 2Y. The toner in the developer DY is electrostatically transferred to an electrostatic latent image formed on the surface of the image carrier 2Y, and the electrostatic latent image is visualized as a yellow toner image.

The yellow toner image is transferred onto the surface of the transfer material S as described above, and the transfer residual toner adhering to the surface of the image carrier 2Y after the transfer is removed by the cleaning device 27.
The cleaning device 27 includes a cleaning case 28 constituted by a part of the unit case 19, a cleaning brush 29 rotatably supported by the cleaning case 28, and a base end portion fixed to the cleaning case 28. The cleaning blade 30 is provided. The cleaning brush 29 and the cleaning blade 30 come into contact with the surface of the image carrier 2Y and scrape off the transfer residual toner on the surface.

FIG. 3 is a cross-sectional view showing a state when the process cartridge is mounted on the image forming apparatus main body. The process cartridge 18Y including the image carrier (photosensitive drum) 2Y is detachably attached to the main body of the image forming apparatus 1. FIG. 3 shows a state when the process cartridge 18Y is mounted on the main body of the image forming apparatus 1.
As shown in FIG. 3, the drum-shaped image carrier 2Y includes a cylindrical image carrier body 39 and flange members 40 and 41 fixed to respective longitudinal ends thereof. The side flange member 40 is rotatably supported by the unit case 19 via a bearing 42, and the back side (upper side in the drawing) flange member 41 is attached to and detached from a shaft 43 that is rotatably supported by the main body of the image forming apparatus 1. Connected as possible.

The shaft 43 is rotatably supported via bearings 47 and 48 on a positioning holder 44 including a side plate 31 on the back side of the main body of the image forming apparatus 1 and a support plate 32 fixed to the side plate 31. Yes.
Further, the joint 50 fixed to the distal end portion of the shaft 43 is engaged with the center hole 49 formed in the rotation center portion of the flange member 41 on the back side. A protrusion (not shown) is formed at the tip of the joint 50, and a hole (not shown) is also formed on the inner peripheral surface of the center hole 49.
The joint 50 and the center hole 49 are fitted to each other, and are engaged with each other, and the rotation of the shaft 43 is transmitted to the image carrier 2Y. In this state, the unit case 19 of the process cartridge 18Y is positioned and held with respect to the main body of the image forming apparatus 1.

When the process cartridge 18Y is pulled toward the front side of the main body of the image forming apparatus 1, that is, in the direction indicated by the arrow F in FIG. 3, the joint 50 and the center hole 49 of the image carrier 2Y are detached, and the image carrier 2Y is included. The process cartridge 18Y can be pulled out to the front side of the main body of the image forming apparatus 1.
On the contrary, when the process cartridge 18Y is pushed into the back side of the main body of the image forming apparatus 1, that is, in the direction opposite to the arrow F, the center hole 49 of the image carrier 2Y and the joint 50 are fitted as shown in FIG. Both projections and holes (not shown) mesh with each other, and the drum-shaped image carrier 2Y and the shaft 43 are positioned concentrically.
A rotating body 51 configured as a gear is fixedly connected to an end portion of the shaft 43 opposite to the end portion to which the joint 50 is fixed via a gear 53 fixed to the shaft of the motor 52. Yes.

FIG. 4 is a schematic block diagram for explaining density variation control means according to the present invention. In the image forming apparatus according to the present invention, one rotation of the developing roller 24 with respect to the developing roller driving source 61 for driving the developing roller 24 based on the development density fluctuation information of the toner image developed by the developing device 22 (FIG. 2). The density fluctuation control means 62 for giving a rotation pulse command is provided so that the density fluctuation can be kept constant.
FIG. 5 is a schematic block diagram for explaining the details of the density fluctuation control means of FIG. In the image forming apparatus according to the present invention, the toner image formed on the image carrier 2Y by the developing device 22 (FIG. 2) is transferred to the transfer material carried on the transfer belt 8 as the transfer material carrier, and the output image is transferred. It is the composition which obtains.

The density fluctuation control means 62 described above detects the density of the test toner pattern formed on the image carrier 2Y and transferred to the transfer material carrier (transfer belt) 8 for detecting density fluctuation components. Is included.
Further, the density fluctuation control means 62 extracts density fluctuation components generated in the cycle of the developing roller 24 (FIG. 4) from the density detection data of a plurality of continuous test toner patterns, and the phase value of the density fluctuation period and Calculation means 64 for obtaining the amplitude value, and calculation means for calculating a displacement target pulse for changing the rotation speed of the developing roller 24 to the rotation speed of the developing roller 24 set so as to cancel out the density fluctuation period based on the calculation result. 65 is included.
The development drive motor (development roller drive source) 61 (FIG. 4) is controlled to be driven by the displacement target setting pulse, and the development roller 61 is feedback-controlled by the density variation control means 62 to thereby develop the development roller. The rotational speed of the developing roller 24 is changed to reduce the density fluctuation in the cycle of the developing roller 24.

FIG. 6 is a schematic diagram showing pattern detecting means for detecting a pattern image for detecting density fluctuation components on the transfer belt formed by the image forming unit. FIG. 6 shows pattern detection means for detecting a pattern image 54 for detecting density fluctuation components on the transfer belt 8 formed by the image forming unit.
The pattern detecting means for detecting the density fluctuation component includes an LED element 55 of a light source for illumination and a light receiving element 56 for receiving reflected light, which are disposed at both ends in the width direction in the image area of the transfer belt 8, and And a pair of condensing lenses 57. The LED element 55 is an LED having a light quantity for producing reflected light necessary for detecting the density fluctuation component detection pattern 54 on the transfer belt 8.
The light receiving element 56 is arranged so that light reflected from the density fluctuation component detection pattern image 54 on the transfer belt 8 passes through the condenser lens 57 and enters. The output of the light receiving element 56 varies depending on the density. The output value is high when the detected density is high, and the output value decreases as the density decreases.

FIG. 7 is a graph showing the output value of the concentration detection sensor and the calculation result. FIG. 7 shows the output value of the density detection sensor. (1) in the figure indicates the output when the measurement pattern progresses, and density fluctuations with periodicity appear.
This period variation is a density variation that occurs due to the shake of the developing sleeve 24b, and occurs once per rotation of the developing sleeve 24b. Therefore, the result of performing Fourier transform on the sensor raw output and extracting only the fluctuation of one rotation cycle of the developing sleeve 24b is shown in (2) in the figure.
Further, the phase and amplitude of the extracted result are calculated, and the calculated values are stored as data in the in-device storage device as density variation data. Further, simultaneously with the measurement process, the result of the home position sensor (described later) (3) in the figure is also stored as data.

FIG. 8 is a schematic view showing a drive transmission mechanism of the developing device. The home position sensor 58 is configured as shown in FIG. 8, and a drive coupling 59 is mounted on the unit side on the developing shaft, and the drive coupling 59 is a claw that transmits drive from the main body side drive coupling. 59-1 is integrally molded.
As a configuration on the apparatus main body side, a final stage development drive gear 60 that transmits driving to the developing unit is rotatably held in a main body side plate (not shown), and the development drive gear 60 is connected to a drive motor (not shown). In this configuration, the drive is transmitted.
A claw 60-1 for transmitting driving to the developing unit (developing device) 22 side is also integrally formed on the developing drive gear 60 on the main body side, and the developing unit 22 is attached and detached in the direction of the arrow in the figure. . In the state where the developing unit is mounted in the apparatus main body, the claw provided on each gear is engaged with each other to transmit the drive.
Further, a protrusion 60-2 provided on the circumference of the developing drive gear 60 on the main body side is a protrusion for detecting the position of the developing drive gear 60, and rotates in synchronization with the developing roller 24. The projection 60-2 is used as a reference mark for the rotational position of the developing roller 24 in the home position sensor 58, and the phase of density fluctuation detected with respect to this reference mark can be specified.

In the above series of operations, the relationship between the density fluctuation and the position of the developing roller 24 from the home position is clarified, and the phase from the home position to the position where the density is the highest is clarified. A portion having a high density indicates that a large amount of toner is supplied with a small gap between the developing roller 24 and the photoreceptor 2Y (FIG. 2).
Therefore, at the position of the developing roller 24 where the density is high, the toner supply amount can be reduced by slowing the rotation speed of the developing roller 24. In this case, it is assumed that a correction table in which the rotation of the developing roller 24 fluctuates according to the density fluctuation amplitude and the density fluctuation becomes constant is provided in advance verification.

FIG. 9 is a graph showing the motor speed and the developing sleeve speed when a motor drive signal capable of density correction is input. Next, FIG. 7 shows the motor rotation speed and the rotation speed of the developing sleeve when the density-correctable motor drive signal calculated by the series of operations is input.
The target rotational speed given to the motor drive is determined in consideration of the reduction ratio with the main body drive gear. Depending on the input target rotational speed, the rotational speed on the developing roller 24 (FIG. 2) is controlled to be slow as the rotational speed when the density is high, and (3) in the figure by performing rotational control. As shown in FIG. 4, the density fluctuation is constant.
In the image forming apparatus embodying the present invention, the developing unit (developing device) 22 (FIG. 2) generally including a developing roller is set to have a life shorter than the life of the main body of the apparatus and can be replaced. Yes. Therefore, when the developing unit 22 is replaced, the deflection of the developing roller 24 (FIG. 2) that has been mounted changes.
Therefore, it becomes necessary to perform the phase control again. In this case, the timing for performing the phase adjustment control is performed only when the developing unit 22 including the developing roller 24 is replaced, so that the adjustment time of the apparatus itself can be shortened, and when the developing unit is replaced. It is possible to suppress the fluctuation of the concentration.

The image forming apparatus embodying the present invention is characterized in that the phase adjustment control is performed when a cover (not shown) capable of exchanging the image forming unit for maintenance or the like is opened and closed. . When the developing unit (developing device) 22 (FIG. 2) including the developing driving roller is removed by maintenance by a service person or the like, the engagement relationship between the main body driving gear and the unit gear may change.
If the engagement relationship changes, the position of the shake between the home position sensor 58 (FIG. 8) and the developing sleeve changes, and there is a possibility that accurate feedback control cannot be performed.
Therefore, the adjustment time of the device itself increases, but in order to perform accurate feedback control, the above-described series of adjustment operations are performed in accordance with the opening and closing of the cover that can be maintained, thereby achieving more stable concentration fluctuations. It becomes possible to suppress.

In the image forming apparatus according to the present invention, a process cartridge is used. The process cartridge 18Y (FIG. 1) includes at least a developing device, includes a rotating body (developing driving gear) 60 (FIG. 1) driven by the above-described rotating driving device, and is attached to and detached from the image forming apparatus. It is configured to be possible.
In the image forming apparatus described above, the rotation body 60 driven by the drive control described above, or the process cartridge having the rotation body in its configuration, the rotation angle displacement data in the circumferential direction of the rotation body 60 for use as a replacement kit. A recording medium (not shown) in which is stored is included.
When the rotating body or the process cartridge as the replacement part is replaced with the corresponding part or the process cartridge in the image forming apparatus, rotation angle displacement data is taken out from the attached recording medium by a reading device (not shown).

For example, the phase and amplitude data is calculated by a personal computer or the like, and the data is input to the image forming apparatus, so that the rotation body 60 or the process cartridge 18Y as a replacement part can be stably replaced. Thus, it is possible to perform the above-described driving, and no adjustment time of the apparatus is generated, so that good image quality can be obtained.
The process cartridge includes the rotating body 60 or the rotating body 60 that is driven by the drive control described above, and forms a recording medium in which the circumferential phase and amplitude data of the rotating body 60 are stored. And a storage medium reading device (not shown) on the main body side. An inexpensive recording medium at the ID chip level is used as the recording medium.
The recording medium is installed in the process cartridge 18Y, and the phase and amplitude data of the rotating body 60, which is the configuration in the process cartridge 18Y, is stored in advance. When the process cartridge 18Y is set in the image forming apparatus and the set is recognized, each constant in the rotating body driving device of the main body is read and set by the main body recording medium reading device.

When the image forming apparatus operates, the rotating body is driven by the rotating body driving device using the taken-in constants. Therefore, even when the rotating body 60 or the process cartridge 18Y as a replacement part is replaced, stable driving can be performed, and no adjustment time for the apparatus is generated, and good image quality can be obtained. become.
The process cartridge 18Y can be configured to affix a decal on which the circumferential phase and amplitude data of the rotating body 60 are printed. The rotating body 60 driven by the drive control according to the present invention or the process cartridge 18Y having the rotating body 60 has a decal on which rotation angle displacement data in the circumferential direction of the rotating body 60 is printed.
The phase and amplitude data of the rotating body 60 are measured and calculated in advance by a measuring jig or the like. Each is obtained as a constant, and the value is printed on a decal and attached to a part or process cartridge 18Y.
When the rotating body 60 driven by the drive control according to the present invention or the process cartridge 18Y having the rotating body 60 is replaced, the decal is removed, the part or the process cartridge 18Y is replaced, and the image forming apparatus operation unit screen ( Each value is input from (not shown).

In this way, stable driving can be performed by easily inputting phase and amplitude data to the image forming means from information recorded on an inexpensive recording means such as a decal, and the adjustment time of the apparatus Therefore, good image quality can be obtained.
Further, the rotating body 60 or the process cartridge 18Y having the rotating body 60 that is driven by the drive control according to the present invention can directly print the phase and amplitude data in the circumferential direction of the rotating body 60.
This direct printing is similar to the case of the decal described above, but has a configuration in which phase and amplitude data are directly written on the part or the process cartridge 18Y. Since printing is performed directly using a printing jig during component measurement, decal paper or the like is not required and recording can be performed at low cost.
Further, in the image forming apparatus according to the present invention, in the configuration in which the image forming means is a color image, the effect obtained can be further exerted in an image obtained by superimposition, as well as density unevenness in a single color. It is possible to further improve the image quality of the color image forming apparatus.

In the image forming apparatus according to the present invention, when the above-described drive control is performed, if the drive motor for driving the developing sleeve attached to the image forming unit of one color is not independently configured, feedback control of each color is performed independently. Can not do it. Therefore, in the color image forming apparatus, by configuring each color development independently, it is possible to achieve the drive control described above, and it is possible to further improve the image quality of the color image forming apparatus.
Further, in the image forming apparatus according to the present invention, the density detection sensor of the test toner pattern to be used and the position sensor which is an information source of position variation control in the color image forming apparatus can be shared. As a result, the detection means in the apparatus can be simplified, and the apparatus cost can be reduced.

1 is a schematic diagram illustrating a color printer that is an example of an image forming apparatus. FIG. 3 is a cross-sectional view showing a configuration of a process cartridge having a yellow image carrier. FIG. 3 is a cross-sectional view illustrating a state when a process cartridge is mounted on the image forming apparatus main body. The schematic block diagram explaining the density | concentration fluctuation | variation control means by this invention. The schematic block diagram explaining the detail of the density | concentration fluctuation | variation control means of FIG. FIG. 3 is a schematic diagram illustrating a pattern detection unit that detects a pattern image for detecting a density variation component on a transfer belt formed by an image forming unit. The figure which shows the output value of a density | concentration detection sensor, and a calculation result with a graph. FIG. 3 is a schematic diagram illustrating a drive transmission mechanism of a developing device. The figure which shows the motor rotation speed at the time of inputting the motor drive signal which can carry out density correction, and the rotation speed of a developing sleeve with a graph. Schematic which shows the conventional developing roller. FIG. 3 is a schematic view of a developing device provided with the developing roller.

Explanation of symbols

1 Image forming device (laser printer)
2Y image carrier (photosensitive drum)
3 Transfer material transport device 8 Transfer belt (transfer material carrier, rotating body)
9Y transfer device (transfer brush)
15 fixing roller 16 pressure roller 18Y process cartridge 22 developing device 24 developing roller 54 pattern image 55 for detecting density fluctuation component LED element 56 light receiving element 57 condensing lens 58 reference mark detecting means (home position sensor)
60 Rotating body (final stage drive gear, main body development drive gear)
60-2 Protrusion 61 Development roller drive source (development drive motor)
62 density variation control means 63 pattern detection means 64 calculation means 65 calculation means DY two-component developer S transfer material

Claims (11)

  An image forming apparatus main body, an image carrier capable of carrying an electrostatic latent image, a developing roller for supplying toner to the electrostatic latent image formed on the image carrier and developing the toner image, and the development roller And a driving source for driving the image forming apparatus, a rotation pulse command is given to the driving source based on density fluctuation information of the developed toner image, and density fluctuation of one rotation of the developing roller is controlled. An image forming apparatus comprising density variation control means for controlling to keep constant.   The density variation control means includes a pattern detection means for detecting the density of a test toner pattern formed on the image carrier and then transferred to the transfer material carrier, and the development from the density of a plurality of consecutive test toner patterns. Calculating means for extracting a density fluctuation component generated in the roller period and obtaining a phase value and an amplitude value of the density fluctuation period; and, based on a calculation result of the calculating means, calculating the rotation speed of the developing roller to determine the density fluctuation period. And a calculation means for calculating a displacement target setting pulse for displacing to a rotational speed that cancels out the rotation, and the drive source of the developing roller is feedback-controlled by the displacement target setting pulse. The image forming apparatus according to 1.   A rotating body that transmits driving of the driving source to the developing roller, a reference mark that serves as a reference for the rotational position of the rotating body, and a reference mark detection unit that detects the reference mark. The image forming apparatus according to claim 1.   4. The image forming apparatus according to claim 1, wherein the timing for calculating the displacement target setting pulse is a timing at which a unit including the developing roller is replaced. 5.   2. The apparatus according to claim 1, wherein the apparatus main body side includes the reference mark and reference mark detection means, and the timing for calculating the displacement target setting pulse is a timing at the time of opening / closing operation of a cover provided in the apparatus main body. The image forming apparatus according to any one of claims 1 to 3.   An image carrier that can carry an electrostatic latent image; and a developing roller that supplies toner to the electrostatic latent image formed on the image carrier and develops the toner image. A process cartridge configured to be attachable to and detachable from the image forming apparatus main body, comprising a rotating body that transmits at least a driving source provided in the main body of the image forming apparatus to the developing roller.   The process cartridge according to claim 6, further comprising a recording medium that stores a phase in the circumferential direction of the rotating body and the amplitude value.   8. The process cartridge according to claim 7, wherein the recording medium is read by a storage medium reading device provided on the image forming apparatus main body side.   An image forming apparatus comprising a plurality of process cartridges according to claim 6.   The image forming apparatus according to claim 9, wherein the developing roller constituting each process cartridge can be driven independently.   The image forming apparatus according to claim 9, wherein the pattern detection unit detects a density of the test toner pattern and detects a position for alignment of a color image.

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