JP2004069946A - Color image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color image forming apparatus in which the time for rotational phase detection of an image carrier is shortened while satisfying the function of the image forming apparatus. <P>SOLUTION: A pattern forming means forming a misalignment detection pattern on a carrying means, a rotational phase detecting means calculating the best rotational phase relationship in which the amount of misalignment of detection colors from the reference colors and the amount of misalignment from the rotational phase are made minimum from the detected result, a phase information storing means storing the rotational phase information determined by the rotational phase detection means to the image forming apparatus, a best phase judging means in which a specified misalignment standard satisfying the amount of misalignment of the detection color to the reference color is provided, the rotational phase detection is carried out, the rotational phase detection is interrupted in the stage where the rotational phase in which the amount of misalignment fulfills the standard value is formed and that phase relationship is judged as the best phase, and a phase adjusting means adjusting the rotational phase in angular speed unevenness of the image carrier, are provided. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a color image forming apparatus such as a color copying machine and a color printer.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a so-called in-line type color image forming apparatus in which photosensitive drums forming a plurality of image carriers are arranged in a line. This is because while the transfer material is carried and conveyed by an electrostatic transfer belt stretched by a plurality of rollers, yellow, magenta, cyan, and black are provided by four photosensitive drums arranged along the transfer material conveyance path. Are sequentially transferred onto a sheet, and a color image is formed by superimposing each color.
[0003]
This configuration has attracted attention in recent years because printing can be performed at high speed.
[0004]
However, since each color is formed by four photosensitive drums, a configuration in which colors are superimposed on one photosensitive drum via four transport paths for each color (hereinafter, simply referred to as a “four-pass method”) ), Higher accuracy is required for the rotational drive of the photosensitive drum.
[0005]
That is, in general, a gear train is used for driving the photosensitive drum, and rotation unevenness of a low frequency such as one rotation component of the gear always occurs. However, in the case of the 4-pass system, the reduction ratio of the drive gear train is set to an integer. By using the combination, it is possible to avoid the accumulated pitch error of the gears and to adjust the image forming position of each color.
[0006]
However, in the case of the in-line method, since the plurality of photosensitive drums are independent, the drive gear train is also independent, and it is difficult to avoid the above-described four-pass method, and the image forming position of each color is shifted. Of the image quality such as color misregistration due to the image quality.
[0007]
Conventionally, as a countermeasure against color misregistration, measures such as detecting the angular velocity of the photosensitive drum, reading an image transferred to a transfer material to detect the speed unevenness, and controlling the rotation of the motor to offset the speed unevenness, In order to reduce relative color misregistration, the rotational phase of each photosensitive drum is adjusted to a desired state.
[0008]
[Problems to be solved by the invention]
However, in the above-described conventional example, the image carrier forming the photosensitive drum is driven by a reduction system via a plurality of gears. A complicated speed waveform including a component of one rotation cycle is obtained. Therefore, high-precision speed unevenness detecting means and motor control are required. Even if the phases of the photosensitive drums are adjusted, the influence of the intermediate gear remains, and the drive unevenness of one rotation period of the image carrier is accurately detected. In addition, the rotational phase of the detected color with respect to the reference color is shifted, and the relative positional shift of the detected color with respect to the reference color must be detected for each rotational phase by using the positional shift detection pattern, which takes time.
[0009]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a color image forming apparatus capable of reducing the time for detecting the rotational phase of an image carrier while satisfying the performance of the image forming apparatus. I do.
[0010]
[Means for Solving the Problems]
The present invention can solve the above-mentioned problems by providing the following configuration.
[0011]
(1) A plurality of image forming units having an optical unit, an image carrier, and the like, and a transport unit that forms an endless belt that sequentially passes through the plurality of image forming units, or mounting / transporting on the transport unit A plurality of transfer means for transferring an image onto a recording material to be transferred,
A pattern forming means for forming a pattern for detecting a displacement on the transport means, and a position formed on the transport means so that a reference color can be detected by one detection unit and a detection color can be simultaneously detected by another detection unit. The rotational phase of the detected color is sequentially adjusted with respect to the reference color by a predetermined angle with respect to the pattern for deviation detection, and from the detected result, the positional deviation amount of the detected color with respect to the reference color and the positional deviation are determined from the rotational phase. Rotation phase detection means for calculating the rotation phase of the angular velocity unevenness of the image carrier which is the minimum, phase adjustment means for adjusting the rotation phase of the angular velocity unevenness of the image carrier, and the rotation phase detection means Having phase information storage means for storing rotation phase information in the image forming apparatus,
A predetermined position deviation standard that satisfies the position deviation amount of the detected color with respect to the reference color is provided, the rotation phase detection is performed, and the rotation phase detection is interrupted when the position deviation amount reaches the rotation phase that satisfies the specification value. A color image forming apparatus, wherein a phase relationship is determined to be an optimum phase.
[0012]
(2) a plurality of image forming units having an optical unit and an image carrier,
A plurality of transfer units for transferring an image onto a conveying unit that forms an endless belt that sequentially passes through the plurality of image forming units, or onto a recording material placed / conveyed on the conveying unit;
A pattern forming means for forming a pattern for detecting a displacement on the transport means, and a position formed on the transport means so that a reference color can be detected by one detection unit and a detection color can be simultaneously detected by another detection unit. The shift detection pattern is coarsely adjusted at predetermined angles for the rotation phase of the detected color with respect to the reference color, and then finely adjusted using the detection result so as to reduce the amount of positional shift. A rotation phase detecting unit that calculates a rotation phase of the angular velocity unevenness of the optimal image carrier in which the positional displacement is minimized from the positional deviation amount and the rotational phase of the detected color with respect to the reference color from the detected result; and In a color image forming apparatus having a phase adjustment unit that adjusts the rotation phase of angular velocity unevenness, and a phase information storage unit that stores the rotation phase information determined by the rotation phase detection unit in the image forming apparatus,
A predetermined position deviation standard that satisfies the position deviation amount of the detected color with respect to the reference color is provided, the rotation phase detection is performed, and the rotation phase detection is interrupted when the position deviation amount reaches the rotation phase that satisfies the specification value. A color image forming apparatus, wherein a phase relationship is determined to be an optimum phase.
[0013]
(3) In the color image forming apparatus described in (1) or (2) above, when rotation phase information is stored in the phase information storage unit, the rotation information is stored in the phase information storage unit when the rotation phase detection unit is executed. A color image forming apparatus, wherein the stored rotation phase is used as an initial value, and rotation phase detection is started from the rotation phase.
[0014]
(4) The color image forming apparatus according to the above (1), (2), or (3), further comprising an exchange detecting unit for detecting the exchange of the image carrier, and rotating when the exchange of the image carrier is detected. A color image forming apparatus that executes a phase detecting unit.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a color image forming apparatus according to the present invention will be described.
[0016]
FIG. 1 is a longitudinal sectional view showing a main part configuration of a color image forming apparatus according to a first embodiment of the present invention, and FIG. 2A is a perspective view showing a main part configuration of a drive unit / drive transmission unit of a photosensitive drum. FIG. 3B is a cross-sectional view illustrating a main configuration of a driving unit / drive transmission unit of the photoconductor drum. FIG. 3 is an explanatory diagram illustrating a main configuration of a driving unit and a control system of the photoconductor drum. Is an explanatory diagram showing a state of color misregistration of each color before control, FIG. 5 is an explanatory diagram showing a state of a signal that detects a phase of a gear that rotationally drives the photosensitive drum, and FIG. FIG. 7 is an explanatory view showing a state in which the color shift of each color after the phase control is eliminated, FIG. 7 is an explanatory view showing a positional shift detecting pattern and an example of its arrangement, and FIGS. FIG. 9 is an explanatory diagram showing the amount of misregistration with respect to the reference color when driving unevenness other than the above is canceled. Explanatory view showing a variation of the displacement amplitude when the rotational phase is varied, and FIG. 10 is a sectional view showing a main configuration in the form of a color image forming apparatus in Embodiment 2 according to the present invention.
[0017]
(Example 1)
In FIG. 1, a color image forming apparatus 100 includes four electrophotographic photosensitive drums 1a, 1b for yellow, magenta, cyan, and black, which are image carriers that are linearly arranged vertically in FIG. 1c, 1d (hereinafter simply referred to as "photosensitive drum 1"), and a transfer material serving as a transfer material carrier that adsorbs and transports the transfer material S by electrostatic attraction facing each photosensitive drum 1. A material transport belt (endless belt) 11 is provided.
[0018]
Each of the photosensitive drums 1 is fixed to a drum shaft serving as a rotation shaft of the photosensitive drum 1, and more specifically, a coupling 36 serving as a first engagement member described later and engaged with the coupling 36. Rotational driving force is transmitted from a drive motor (not shown) serving as a drive source to the gear 18 on the coupling 33 side serving as the second engagement member to be connected, and is driven to rotate counterclockwise in FIG. a), (b)).
[0019]
The primary chargers 3a, 3b, 3c and 3d (hereinafter simply referred to as "primary chargers") serving as charging means for uniformly charging the surface of the photosensitive drum 1 are arranged around the photosensitive drum 1 in order from the upstream side in the rotation direction. Exposure means 4a for irradiating a laser beam on the surface of the photosensitive drum 1 uniformly charged by the primary charger 3 based on image information to form an electrostatic latent image. , 4b, 4c, and 4d (hereinafter, simply referred to as “exposure means 4”).
[0020]
Further, developing means 5a, 5b, 5c, and 5d (hereinafter simply referred to as "developing means 5") for attaching toner of each color to the surface of the photosensitive drum 1 on which the electrostatic latent image is formed to visualize as a toner image. Cleaning means 6a, 6b, 6c, 6d (hereinafter, simply referred to as "cleaning means 6") for removing the toner remaining on the surface of the photosensitive drum 1 after the transfer.
[0021]
The photoreceptor drum 1, the primary charger 3, the developing means 5, and the cleaning means 6 are integrated with the apparatus main body 100 as process cartridges 7a, 7b, 7c, 7d (hereinafter simply referred to as "process cartridge 7"). It is configured to be detachable. Further, a unit for detecting replacement of a process cartridge (not shown) is provided, and the loaded state is detected during the initialization operation.
[0022]
Further, a transfer material transport belt (endless belt) 11 is formed on the surface of the photosensitive drum 1 on a transfer material S carried and transported by the transfer material transport belt 11 with a transfer material transport belt (endless belt) 11 interposed therebetween at a position facing each photosensitive drum 1. Transfer rollers 12a, 12b, 12c, and 12d (hereinafter, simply referred to as "transfer rollers 12") serving as transfer units for transferring the toner image are arranged.
[0023]
The drive unit is located on the front left side of the machine, and applies a rotational driving force to the four color process cartridges arranged in a substantially vertical direction. Each process cartridge includes the photosensitive drum 1, the developing unit 4, the cleaning unit 6, and the like, and supplies all of these driving forces.
[0024]
Since the cartridges can be attached and detached independently of each color, the drive transmission units are also arranged in a substantially vertical direction independently of each color, and are directly transmitted to the photosensitive drum 1 which requires rotation accuracy. For example, the driving of the developing unit 4 and the cleaning unit 6 may be transmitted in another system. The driving force supplied to the cartridge is distributed to each element by a driving system in the cartridge.
[0025]
As shown in FIGS. 2A and 2B, a gear 18 for driving the process cartridge, a shaft portion 32a that rotates integrally with the gear, and an integral portion of the shaft portion are provided inside the driving means. A coupling portion 33 for rotating and transmitting a rotational driving force to the process cartridge, and a positioning hole 34 for fitting to the drum shaft 22 fixed concentrically with the photosensitive drum 1 to determine a position. Have been. This integral component can be a resin molded product.
[0026]
As shown in FIG. 2, the shaft portion 32a is supported by the cylinder bearing portion 35 provided on the main body side only in the shaft portion 32a in the vicinity of the gear root with required accuracy and freely rotatably and linearly. The periphery of 33 is wide enough that the positioning hole 34 does not conflict with the shaft position, which is determined by fitting the drum shaft 22 to be described later, and that the positioning hole 34 does not hinder the engagement of the coupling. Clearance is provided.
[0027]
Although the gear shaft is tilted due to the positional accuracy between the cylinder bearing portion 35 and the drum shaft 22, there is no actual harm by making the distance from the shaft portion 32a near the gear root to the positioning hole 34 sufficiently long.
[0028]
The gear 18 and the integral part are movable in the axial direction, and are pressed in the direction of the photosensitive drum 1 by a leaf spring 37.
[0029]
A drum shaft 22 that rotates integrally with the photosensitive drum 1 is fixed to the photosensitive drum 1 using a parallel pin 25, and the drum shaft 22 is accurately positioned on a machine body via a bearing 38. I have.
[0030]
A non-drive side (driven side) coupling 36 is fixed to the end of the drum shaft 22, meshes with the drive side (drive side) coupling 33, and the rotational driving force is transmitted.
[0031]
The drive-side coupling and the non-drive-side coupling are triangular spiral-shaped couplings as shown in FIGS. 2A and 2B, and when driven in a predetermined direction, they are always engaged with each other. ing.
[0032]
In FIG. 3, the photosensitive drums 1y, 1m, 1c, and 1k (hereinafter referred to as the photosensitive drums 1) are engaged with the photosensitive drums 1 by motors 41y, 41m, 41c, and 41k (hereinafter, referred to as motors 41). The photosensitive drum 1 is driven via the gear 18.
[0033]
A target for detecting a phase is provided on the teeth 31 of the gear 18, and a phase signal is detected once per rotation by an optical or magnetic phase detector (42y, 42m, 42c, 42k) 42. can do.
[0034]
Further, an image detection sensor 44 is provided so as to face the transfer material conveying belt 11, and an image on the transfer material conveying belt 11 can be optically detected.
[0035]
In the configuration of the present embodiment, the main component of the angular velocity unevenness is only one rotation cycle of the photosensitive drum 1, so that the pattern formed on the photosensitive drum 1 at equal time intervals is transferred to the transfer material transport belt 11. Then, when reading is performed by the image detection sensor and the accumulated fluctuation component of the pattern interval is obtained, a sine waveform as shown in FIG. 4 is obtained.
[0036]
In FIG. 4, the horizontal axis represents the distance from the leading end of the image, and the vertical axis represents the displacement.
[0037]
In order to determine the phase relationship of the four colors, processing is performed such that each color is imaged and detected while managing the image formation start timing of each color, a sine waveform is obtained, and the sine waveform is corrected based on the start timing interval and compared. Just do it.
[0038]
In addition, as shown in FIG. 4, when Bk is used as a reference, the color shift relative to the Bk color can be reduced by shifting the Y color toward the image front end by the distance y. Similarly, the color M may be shifted by the distance m, and the color C may be shifted by the distance c. However, this rotation phase detection requires a predetermined time, and if it is performed frequently, a loss of image forming time occurs.
[0039]
Therefore, a phase detection device 42 that detects the phase of the gear 18 that rotates the photosensitive drum 1 is used, and control is usually performed based on this phase information.
[0040]
When the phase waveform detected by the phase detection device 42 is in the state as shown in FIG. 5, if the phase of the Y-color gear 18y is controlled so as to be turned earlier by the time y 'corresponding to the distance y in FIG. The relative color shift between the Bk color and the Y color is reduced. Similarly, the phase control may be performed so that the M-color gear 18m is rotated by a time m 'corresponding to the distance m, and the C-color gear 18c is rotated by a time c' corresponding to the distance c.
[0041]
The control of the phase can be performed by adjusting the speed of the motor 41.
[0042]
When such phase control is performed and the above-described phase relationship is obtained, the result is as shown in FIG. 6, and the relative color shift can be reduced to about １ ／ or less.
[0043]
Hereinafter, the operation of the first embodiment according to the present invention will be described.
[0044]
The means for detecting the replacement of the process cartridge detects that the CRG has been replaced or newly loaded, and executes the rotation phase detection. A misregistration detection pattern as shown in FIG. 7 is formed on the transfer material transport belt 11 and read by the image detection sensors 44 provided on both sides of the transfer material transport belt 11 to detect the amount of misregistration of each color.
[0045]
FIG. 7 shows a pattern for detecting the amount of displacement in the paper transport direction. In this example, a reference color a (hereinafter, Bk: black) is provided on one side, and a detected color b (hereinafter, Y: yellow, M: magenta, C: cyan). a1 to a19 and b1 to b19 indicate the detection timing of each pattern. Arrows indicate the transport direction of the transfer material transport belt 11.
[0046]
Since the reference color and the detected color are arranged at the same position in the conveyance direction in the misregistration detection pattern, the pattern is less susceptible to speed unevenness due to the transfer material conveyance belt 11.
[0047]
As shown in FIG. 8, it is possible to cancel by setting the pitch of the misregistration detection pattern to be an integral multiple of the drive unevenness other than the photosensitive drum 1.
[0048]
The rotation phase of the reference color is fixed, the rotation phase of the detected color with respect to the reference color is shifted and detected at a predetermined angle, and the above-described detection is repeated. A waveform as shown in FIG. 9 is obtained for the relationship between the rotation phase and the amplitude of the color, and it is easy to determine the optimum phase of each color.
[0049]
Alternatively, there is a method of roughly adjusting the rotation phase of the photosensitive drum 1 for the detected color with respect to the reference color and then finely adjusting the rotation phase, thereby shortening the time. In the present embodiment, first, a misregistration pattern is detected every 120 ° with respect to the reference phase. Using the detection result, an angle between the phase angles having small amplitudes of the displacement amount is detected. Further, using the above detection result, measurement is performed during a phase angle where the amplitude of the displacement amount is small, and finally, the angle at which the amplitude of the displacement amount becomes the minimum is determined as the optimum phase. By feeding back the phase detection result to the rotation phase control of the motor 41 from the phase, the color shift can be reduced.
[0050]
Here, similarly to both of the above-described rotational phase detecting means, the rotational phase detecting means is determined to be the optimum phase when the standard is satisfied during the execution of the rotational phase detecting means, thereby shortening the time of the rotational phase detecting means. be able to. Further, when the phase information is stored in the phase information storage means, for example, when the process cartridge is replaced, there is no change in the image forming apparatus factor affecting the rotation phase. By starting the detection, the time required for the phase detection can be reduced.
[0051]
Further, the stored phase information is used as an initial value, and while the phase information is 120 °, for example, when the phase information is 120 °, the phase information is measured in the order of 120 °, 90 °, and 150 ° while distributing the phase at a predetermined phase angle. A method in which the position slightly shifted from the stored phase information is set as an initial value, and the phase is sequentially shifted from the phase, and measurement is performed. For example, when the phase information is 120 °, 90 °, 120 °, 150 °,. There is also a method of detecting the optimum phase by measuring in order.
[0052]
In FIG. 9, the vertical axis indicates the amplitude of the positional shift amount of the detected color with respect to the reference color, and the horizontal axis indicates the rotation phase of the detected color with respect to the reference color. The amplitude of the displacement amount of the photosensitive drum 1 of the detected color with respect to the displacement reference pattern reference color is:
ΔC ₁ (θ) = MAX (a1-bc1, a2-bc2,..., A18-bc18, a19-bc19) −MIN (a1-bc1, a2-bc2,..., A18-bc18) , A19-bc19) / 2 (Equation 1)
ΔY ₁ (θ) = MAX (a1-by1, a2-by2,..., A18-by18, a19-by19) -MIN (a1-by1, a2-by2,..., A18-by18) , A19-by19) / 2 (Equation 2)
ΔM ₁ (θ) = MAX (a1-bm1, a2-bm2,..., A18-bm18, a19-bm19) −MIN (a1-bm1, a2-bm2,..., A18-bm18) , A19-bm19) / 2 (Equation 3)
Is represented by
[0053]
When there is a plurality of speed irregularities other than those caused by the transfer material transport belt 11, the pitch / moving averaging process of the misregistration detection pattern is performed as in the following equation to extract the speed irregularities of the photosensitive drum 1. Can be easily detected.
[0054]
ΔC ₁ (θ) = MAX (Average (a1-bc1, a2-bc2, a3-bc3), Average (a2-bc2, a3-bc3, a4-bc4)... Average (a16-bc16, a17-bc17, a18-bc18), Average (a17-bc17, a18-bc18, a19-bc19))-MIN (Average (a1-bc1, a2-bc2, a3-bc3), Average (a2-bc2, a3-bc3, a4- average (a16-bc16, a17-bc17, a18-bc18) / 2 (equation 4)
ΔY ₁ (θ) = MAX (Average (a1-by1, a2-by2, a3-by3), Average (a2-by2, a3-by3, a4-by4)... Average (a16-by16, a17-by17, a18-by18), Average (a17-by17, a18-by18, a19-by19))-MIN (Average (a1-by1, a2-by2, a3-by3), Average (a2-by2, a3-by3, a4- by4) ... Average (a16-by16, a17-by17, a18-by18) / 2 (Equation 5)
ΔM ₁ (θ) = MAX (Average (a1-bm1, a2-bm2, a3-bm3), Average (a2-bm2, a3-bm3, a4-bm4)... Average (a16-bm16, a17-bm17, a18-bm18),
Average (a17-bm17, a18-bm18, a19-bm19))-MIN (Average (a1-bm1, a2-bm2, a3-bm3), Average (a2-bm2, a3-bm3, a4-bcm4)... Average (a16-bm16, a17-bm17, a18-bm18) / 2 (Equation 6)
(Example 2)
Next, a second embodiment will be described with reference to FIG.
[0055]
FIG. 10 is an explanatory cross-sectional view illustrating a configuration of an image forming apparatus according to a second embodiment of the present invention. The description of the same components as those in the first embodiment is omitted.
[0056]
In this embodiment, as shown in FIG. 10, the toner image formed on the surface of the photosensitive drum 1 facing the photosensitive drum 1 serving as a plurality of image carriers arranged in a horizontal direction is primarily transferred. An intermediate transfer belt 54, which is an intermediate transfer member, is stretched by a driving roller and a driven roller, and a secondary transfer unit 55 is disposed at a position facing the driven roller with the intermediate transfer belt 54 interposed therebetween. .
[0057]
In the same manner as in the first embodiment, the toner images formed on the respective photosensitive drums 1 are subjected to intermediate transfer by the operation of transfer units 56a, 56b, 56c, 56d (hereinafter, simply referred to as "transfer unit 56"). The primary transfer is performed on the belt 54.
[0058]
On the other hand, the transfer material S fed out from the paper feed cassette 50 by the pickup roller 51 is separated and fed one by one by a separating means (not shown), and then sent to the registration roller pair 53 by the conveyance roller pair 52. By the pair 53, the toner image is conveyed between the intermediate transfer belt 54 and the secondary transfer unit 55 at a predetermined timing, and the toner image primarily transferred to the intermediate transfer belt 54 by the operation of the secondary transfer unit 55 is secondarily transferred. You.
[0059]
The transfer material S on which the toner image has been transferred is conveyed by a discharge roller pair 57 after the toner image is fixed by the fixing unit 21, and discharged onto a discharge tray 24 provided at an upper portion of the apparatus main body 200.
[0060]
According to the second embodiment, the same effects as those of the first embodiment can be obtained.
[0061]
【The invention's effect】
As described above, according to the present invention, by setting a predetermined displacement standard and detecting angular velocity unevenness of the photosensitive drum, the displacement of the detected color with respect to the reference color can be reduced while satisfying the performance of the image forming apparatus. The number of times of detection for each rotation phase can be reduced, and the time required to detect the rotation phase of the unevenness in the speed of the image carrier can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a main part configuration of a color image forming apparatus according to a first embodiment of the present invention. FIG. 2 (a) shows a main part configuration of a drive unit / drive transmission unit of a photosensitive drum. FIG. 3B is a cross-sectional view illustrating a main configuration of a drive unit / drive transmission unit of the photosensitive drum. FIG. 3 is an explanatory diagram illustrating a main configuration of a drive unit and a control system of the photosensitive drum. FIG. 5 is an explanatory diagram showing a state of color misregistration of each color before control. FIG. 5 is an explanatory diagram showing a state of a signal detecting a phase of a gear for rotating and driving the photosensitive drum. FIG. 7 is an explanatory view showing a state in which the color misregistration of each color is eliminated. FIG. 7 is an explanatory view showing a misregistration detection pattern and an example of its arrangement. FIG. 8A and FIG. FIG. 9 is an explanatory diagram showing a positional shift amount with respect to a reference color when unevenness is canceled. Cross-sectional view showing the main portions of a color image forming apparatus configured according to the second embodiment according to the position diagram showing the change of the displacement amplitude [10] The present invention when changing the phase [Description of symbols]
1 Photoconductor drum (image carrier)
3 Primary Charger 4 Exposure Means 5 Developing Means 6 Cleaning Means 7 Process Cartridge 11 Transfer Material Conveying Belt (Conveying Means, Endless Belt)
18 gear 21 fixing means 22 drum shaft 24 discharge tray 33 coupling (second engaging member)
36 Coupling (first engagement member)
42 phase detection device 44 image detection sensor 50 paper feed cassette 51 pickup roller 52 transport roller 53 registration roller 54 intermediate transfer belt 55 secondary transfer means 56 transfer means

Claims (4)

A plurality of image forming units having an optical unit and an image carrier,
A plurality of transfer units for transferring an image onto a conveying unit that forms an endless belt that sequentially passes through the plurality of image forming units, or onto a recording material placed / conveyed on the conveying unit;
Pattern forming means for forming a pattern for detecting a displacement on the transport means,
A pattern for detecting misregistration formed so that one detection unit can detect the reference color and another detection unit can detect the detection color at the same time on the transporting means. A rotation phase detecting unit that sequentially adjusts the angle of each of the angles and calculates an optimal rotation phase relationship that minimizes the amount of displacement from the detected result and the displacement amount of the detected color with respect to the reference color and the rotation phase;
Phase adjustment means for adjusting the rotation phase of the angular velocity unevenness of the image carrier,
In a color image forming apparatus having phase information storage means for storing the rotation phase information determined by the rotation phase detection means in the image forming apparatus,
A predetermined position deviation standard that satisfies the position deviation amount of the detected color with respect to the reference color is provided, the rotation phase detection is performed, and the rotation phase detection is interrupted when the position deviation amount reaches the rotation phase that satisfies the specification value. A color image forming apparatus, wherein a phase relationship is determined to be an optimum phase. A plurality of image forming units having an optical unit and an image carrier,
A plurality of transfer units for transferring an image onto a conveying unit that forms an endless belt that sequentially passes through the plurality of image forming units, or onto a recording material placed / conveyed on the conveying unit;
Pattern forming means for forming a pattern for detecting a displacement on the transport means,
A pattern for detecting misregistration formed so that one detection unit can detect the reference color and another detection unit can detect the detection color at the same time on the transporting means. Coarse adjustment for each angle, and then, using the detection result, finely adjust so as to reduce the amount of positional deviation. From the detected result, the amount of positional deviation of the detected color with respect to the reference color and the rotational phase are used. Rotation phase detection means for calculating an optimal rotation phase relationship that minimizes the amount of displacement,
Phase adjustment means for adjusting the rotation phase of the angular velocity unevenness of the image carrier,
In a color image forming apparatus having phase information storage means for storing the rotation phase information determined by the rotation phase detection means in the image forming apparatus,
A predetermined position deviation standard that satisfies the position deviation amount of the detected color with respect to the reference color is provided, the rotation phase detection is performed, and the rotation phase detection is interrupted when the position deviation amount reaches the rotation phase that satisfies the specification value. A color image forming apparatus, wherein a phase relationship is determined to be an optimum phase. When the rotation phase information is stored in the phase information storage means, when the rotation phase detection means is executed, the vicinity of the rotation phase stored in the phase information storage means is set as an initial value, and the rotation phase is detected from the rotation phase. 3. The color image forming apparatus according to claim 1, wherein the process is started. In an image forming apparatus having exchange detection means for detecting exchange of an image carrier,
4. The color image forming apparatus according to claim 1, wherein a rotation phase detecting unit is executed when replacement of the image carrier is detected.

Images