JP3135077B2 - Belt meandering correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt meandering correction device for correcting a deviation of a photosensitive belt in an image forming apparatus such as a copying machine or a laser printer using the photosensitive belt.

[0002]

2. Description of the Related Art A conventional photoreceptor belt shift correcting device is
For example, Japanese Patent Laid-Open Publication No. Sho 58-43484 discloses a "belt lateral position control device".
There is a "belt meandering correction device" disclosed in Japanese Patent No. 0624 (US Pat. No. 4,527,686).

A "belt lateral position control device" disclosed in Japanese Patent Application Laid-Open No. 58-43484 controls the lateral position of a belt arranged to move along a predetermined traveling path. Means for pivotally supporting the belt, and detecting that the belt has laterally deviated from a predetermined traveling path, and transmitting this to the supporting means in response thereto. Means for removing the belt from the detecting means while the belt is moving along the predetermined traveling path, and rotating the belt by the detecting means to return the belt to the predetermined traveling path. And means for tilting the support means in response to the

A "belt meandering correction device" disclosed in Japanese Utility Model Laid-Open No. 58-110624 (US Pat. No. 4,527,686) winds a belt body around a plurality of rollers.
At least one of the rollers is provided so as to displace its axis at a position where the belt moves toward the right or left with respect to the traveling direction. A sensor for optically detecting the position of the roller is provided on one end side of the belt body, and a cam for rotating a predetermined angle by a signal from the sensor is provided to displace the axis of the roller to the right side or the left side. A heart displacement device is provided.

[0005] As described above, in the conventional "belt lateral position control device" and "belt meandering correction device", the inclination angle of the belt deviation correction roller is provided equally to the left and right, and the mechanism is inclined to the maximum inclination angle. I have. In such a mechanism, depending on a combination of a specific belt conveying device and a specific belt, a time in which the belt is shifted left and right may differ. For example, when the B-belt is incorporated in the A-belt device, the belt shift time from left to right is 30 sec, and the belt shift time from right to left is 45 s.
ec, when the C-belt is incorporated into the A-belt device, the belt shift time from left to right is 10 sec.
In some cases, the belt shift time from right to left is 60 seconds. For this reason, in the conventional apparatus, the inclination angle of the correction roller is set to the minimum angle at which deviation can be corrected for all expected belts. The inclination angle of the correction roller is always constant.

[0006]

However, a conventional "lateral belt position control apparatus" as described above.
In addition, in the belt meandering correction device, there are variations in belt processing accuracy (periphery difference between left and right, cylindricity, etc.).
If the approach time is too fast, the following problems have occurred.

(1) Since the belt moves at the transfer position,
There is a problem that an image that is originally a right angle on a recording paper becomes a parallelogram image. Further, although image distortion does not occur in the exposure processing during flash exposure (entire exposure), there is a problem that distortion occurs in the exposure position in the scan exposure processing.

(2) There is a problem in that the concentrated stress on the photoreceptor belt becomes excessive, thereby causing early damage of the photoreceptor belt.

(3) Since belt waviness occurs when the belt is shifted, there is a problem in that quality problems such as image deformation, development omission, transfer omission, and cleaning failure occur.

If the belt shift time is too fast as described above, there is a problem that the image quality of the entire apparatus is generally lowered and reliability is lacking.

The present invention has been made in view of the above, and it is possible to always perform highly reliable belt meandering correction by eliminating a problem in a photosensitive belt and an image forming unit due to too fast a shift time. With the goal.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is to reduce a belt shift generated when a belt body runs.
The belt meandering correction apparatus having a belt correction roller to correct the belt deviation tilts more direction opposite the
When the belt moves from the right limit to the left limit
And time to move from left limit to right limit
In it, when said deviation time of the belt body is less than the reference time, it is provided a belt meandering correction apparatus provided with a tilt change means capable of changing smaller than the maximum value of the inclination angle of the belt correcting roller is there.

The tilt changing means includes a deflection shaft for generating the tilt of the belt correction roller by rotation of the eccentric shaft, a drive motor for driving the deflection shaft, and the belt.
Edge detecting means for detecting an edge of the body;
Measuring means for measuring the shift time of the belt body based on the detection signal of the output means; and motor control for turning on / off the drive motor based on the time measured by the measuring means and a preset reference time. Means. Further, when the shift time measured by the measuring means is shorter than a reference time, the ON time of the drive motor is increased by a predetermined value, and the inclination angle of the belt correction roller is increased.
It is desirable to make it smaller than the maximum value . Further, the measurement of the belt shift time by the measuring means is measured for each shift direction of the belt body, and in response to each shift time, the ON time of the drive motor is increased by a predetermined value to thereby adjust the inclination angle of the belt correction roller. It is desirable to make it smaller than the maximum value .

[0014]

In the belt meandering correction device of the present invention, the inclination changing means is provided when the shift time of the belt body is less than the reference time.
The inclination angle of the belt correction roller is changed to be smaller than the maximum value . To be more specific, the measuring unit measures the shift time of the belt body.
Measurement is performed based on the detection signal of the edge detection means, and the motor control means compares the measured shift time with a preset reference time to perform ON / OFF control of the drive motor.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A belt meandering correction apparatus according to the present invention will be described below in detail with reference to the drawings, taking an example in which the apparatus is applied to a copying machine.

FIG. 1 is an explanatory diagram showing a schematic configuration of a copying machine according to this embodiment. Reference numeral 101 denotes a document stacker on which a document to be copied is set, reference numeral 102 denotes an automatic document feeder (hereinafter, referred to as ADF) for automatically transporting a document placed on the document stacker 101, and reference numeral 103 denotes a document for reading an image. Is a contact glass on which is mounted, 104 is an exposure lamp for performing overall exposure using a xenon lamp for illuminating the original, 105 is a reflecting mirror for uniformly irradiating the surface of the original with light from the exposure lamp 104, and 106 to 108 are originals for the original. An imaging optical system composed of a mirror and a lens group for guiding reflected light obtained by illumination to the photosensitive belt 109. A photosensitive belt 109 for forming an electrostatic latent image by an electrophotographic process is a transmission belt type. It employs an OPC (organic optical semiconductor) and is incorporated in a photoreceptor unit (FIG. 2 described later) that is detachable from a copying machine.

Reference numeral 110 denotes a charging charger for charging the surface of the photoreceptor belt 109 in a scorotron manner prior to exposure processing, and 111 denotes a magnetic brush roller 111a (see FIG. 1) for applying toner to the electrostatic latent image formed by the exposure processing. 2)
A developing unit 112 for attaching (developing) the toner image formed on the photosensitive belt 109 to a recording paper surface;
A separation charger 114 for electrically separating the recording paper adhered thereon is provided with a photoreceptor belt 109 on which the transfer process is completed.
Magnetic brush roller 1 for cleaning toner remaining on top
14a (see FIG. 2), the cleaning unit 115 recovers the charge outside the necessary area after the charging process.
This is an eraser that is erased by the irradiation light of D.

Reference numeral 116 denotes a paper feeder for feeding recording paper of a predetermined size selected from an operation unit (not shown) one by one according to an instruction from the controller, and 117 denotes a toner on the photosensitive belt 109. A registration roller 118 that conveys the recording paper at a predetermined timing so as to match the leading edge of the image has a built-in heater inside, and its surface is made of a heat-resistant and mold-releasable material and is controlled at a predetermined temperature. A rotating fixing roller 119 is a pressure roller which rotates while being urged by a predetermined pressure while facing the fixing roller 118, and a discharge tray 120 for discharging recording paper after image formation is completed.

The operation of the above configuration will be described with reference to an example in which copying is performed using the ADF 102. First, a copy process is started by pressing a print start key of an operation unit (not shown) arranged at the upper part of the copier, and the ADF 102 conveys the originals one by one from the original stacker 101 to form a contact glass. 1
03. The original placed on the contact glass 103 is turned on by the
The reflected light (reading light) is projected (exposed) onto the surface of the photoreceptor belt 109 by the imaging optical systems 106 to 108. When the reading light is projected on the photoreceptor belt 109, the charge of the projected portion is erased by the intensity of the reading light, and an electrostatic latent image is formed. The electrostatic latent image is subsequently subjected to a developing process by the developing unit 111 to form a toner image.

When the formation of the electrostatic latent image on the photoreceptor belt 109 is completed, the ADF 102 discharges the document to a document discharge tray on the ADF 102, and then conveys the next document and places it on the contact glass 103. Place.

The recording paper conveyed by the paper feeding / conveying section 116 is conveyed to the photoreceptor belt 109 at a proper timing so as to match the leading end of the toner image formed on the photoreceptor belt 109 by the registration roller 117. Is done.

The transfer charger 112 transfers the toner image on the photoreceptor belt 109 to the conveyed recording paper, and the recording paper after the transfer processing is separated from the photoreceptor belt 109 by the separation charger 113. The sheet is fed to the nip between the fixing roller 118 and the pressure roller 119, subjected to a fixing process, and discharged to the sheet discharge tray 120, thereby completing a series of processes.

The photoreceptor belt 109 after the transfer process
The cleaning unit 114 removes the residual toner, and the residual charge is erased and initialized. Then, the apparatus enters a standby state until the next image processing command is issued.

FIG. 2 is an explanatory diagram showing a schematic configuration of the photoconductor unit. In the figure, reference numeral 201 denotes a support for arranging and supporting each component of the photoconductor unit at a predetermined position, 202 denotes a driving roller that runs around the photoconductor belt 109 for driving, and 203 denotes a rotational force applied to the driving roller 202. In this embodiment, the photosensitive belt 109 is driven independently using a DC servo motor. Also, 204
Is disposed at a position facing the transfer / separation unit as shown in the figure.
A roller driven by rotation (hereinafter referred to as a belt correction roller) for correcting a deviation (meandering) of the photosensitive belt 109. Reference numeral 205 denotes the magnetic brush roller 1 of the developing unit 111.
A development backup roller disposed at a position facing the photoreceptor belt 109 and inside the photoreceptor belt 109 to maintain a development gap between the photoreceptor belt 119 and each magnetic brush roller 111a at a constant interval, and 206 is a cleaning magnetic brush roller 114a At a position opposed to the photosensitive belt 10
9 is a cleaning backup roller that is disposed inside the cleaning roller 9 and maintains a cleaning gap between the photosensitive belt 109 and the cleaning magnetic brush roller 114a at a constant interval.

An FL 207 is disposed in the photoconductor unit, and performs a photo-elimination process on the photoconductor belt 109 from the back side.
Lamp 208, FL cover of FL lamp 207, 20
Reference numeral 9 denotes a cleaning pad for removing extraneous matter on the back side of the photoreceptor belt 109;
It is a sensor that detects seams of the photoreceptor belt 109 and meandering during running. The OPC sensor has three built-in photo interrupters, and detects the belt edge of the photosensitive belt 109 by using two of them. 310 is the photoreceptor belt 10
Reference numeral 9 denotes a meandering correction tracking motor, and reference numeral 311 denotes a sector detector that detects a semicircular end of a sector plate 306 (FIG. 3 described later) using a photo interrupter.

FIG. 3 is an explanatory view showing a tracking mechanism (deviation correcting mechanism) of the photoreceptor unit. FIG.
FIG. 3A shows a main configuration for correcting the belt deviation of the photosensitive belt 109, and FIG. 3B shows a driving unit driven by a tracking motor. In the figure, 301 and 302 are a drive roller 202, a belt correction roller 204,
Sliders 303 each supporting the end of each backup roller or the like via a bearing or the like are provided with a bearing 304 which is loosely fitted between the front and rear sliders 301 and 302 so as to be mounted on the shaft, and both ends are formed as eccentric shafts. Deflection axis, 305 is slider 3
It is a fulcrum position which becomes a rotation fulcrum of 01 and 302.

In FIG. 3B, reference numeral 306 denotes a semicircular sector plate which is mounted on the deflection shaft 303,
Is a gear that is mounted on the deflection shaft 303 and receives rotational driving force, 308 is an idle gear that meshes with the gear 307, 30
Reference numeral 9 denotes a worm gear that is axially mounted on the output shaft of the tracking motor 310 and meshes with the idle gear 309. Reference numeral 310 denotes a tracking motor that drives the deflection shaft 303 to rotate.

The tracking mechanism (deviation correcting mechanism) of the photoconductor unit configured as shown in FIGS. 2 and 3 will be described. In the copying machine of this embodiment, the photosensitive belt 10
9, the belt shifts in the front-rear direction during rotation. Further, when correcting the belt deviation, it is necessary to minimize stress and distortion on the photosensitive belt 109. For this reason, in this embodiment, the deviation of the photosensitive belt 109 is corrected by an axis center moving method in which the axis of the belt correction roller 204 is tilted up and down with respect to the horizontal position. The belt correction roller 204 and the deflecting shaft 303 are mounted on the front and rear sliders 301 and 302. Further, since both ends of the deflecting shaft 303 are eccentric shafts, each time the deflecting shaft 303 rotates half a turn, the sliders 301 and 3
02 moves around the fulcrum position 305. The movement of the sliders 301 and 302 causes the belt correction roller 204 to perform a rotational motion in the vertical direction.

The rotation of the deflection shaft 303 is controlled by a tracking motor 310 provided in the photosensitive unit.
Execute by The rotation of the tracking motor 310 is
Worm gear 309 → idle gear 308 → gear 307
To rotate the deflection shaft 303 half a turn. This half-rotation control of the deflection shaft is executed by sector detection. That is, the rotation position of the sector plate 306 is detected by the sector detector 311 . The tracking motor 310 is turned on by this detection signal.
N / OFF control is performed. The direction of the inclination of the belt correction roller 204 is detected by the sector detection.

FIG. 4 shows a photosensitive belt 109 according to the present invention.
It is explanatory drawing which shows the deviation correction principle. FIG. 4A shows the case where the photosensitive belt 109 is shifted to the rear side, and FIG. 4B shows the case where the photosensitive belt 109 is shifted to the front side.
The principle of correcting the deviation of the photoconductor belt 109 is that an angle difference is generated between the upper surface (exposure side) and the lower surface (developing unit 111 side) of the photoconductor belt 109 due to the inclination of the belt correction roller 204. The deviation of the photoreceptor belt 109 is corrected using the angle difference (entering angle and unloading angle).

In the above description, the photosensitive belt 109
Is detected by the OPC sensor 210 at the edge of the photoreceptor belt 109 and the tracking motor 310 is turned on.
The belt correction roller 204 moves in the opposite direction by rotating the deflection shaft 303 half a turn. With the movement of the belt correction roller 204, the photosensitive belt 1
09 moves in the opposite direction. The OPC sensor 210-3
When two photo-interrupters of one photo-interrupter are simultaneously in a shielded or open state, the inclination of the belt correction roller 204 is reversed.

FIG. 5 shows a photosensitive belt 109 according to the present invention.
FIG. 4 is an explanatory view showing a belt tension mechanism of FIG. In the drawing, reference numeral 501 denotes a tension spring disposed on the front and rear sliders 301 and 302 to bias the photosensitive belt 109 at a predetermined pressure, and 502 denotes a tension spring 501.
A tracking adjustment nut for adjusting the urging force (spring length at the time of pressurization);
A hook 504 is used to pressurize / depressurize the photoreceptor belt 109, a cam 504 for sliding the hook 503, and a handle 505 for rotating the cam 504.

In the above description, the belt tension of the photoreceptor belt 109 is performed by the tension spring 501 applied to the front and rear sliders 301 and 302.
When the handle 505 is at the set position, the tension force of the tension spring 501 causes the belt correction roller 20 to move.
No. 4 always keeps the photosensitive belt 109 stretched. Conversely, when attaching or detaching the photoreceptor belt 109, the handle 505 is operated to the release position, and the tension spring 50 is moved.
This is performed when the tension of the photoreceptor belt 109 is released by weakening the tension due to 1.

FIG. 6 is an explanatory view showing a drive unit of the photosensitive unit according to the present invention. In the figure, reference numeral 601 denotes a pulley provided on the output shaft of the drive motor 203 and the drive roller 2.
The drive motor 2 is wound around a pulley provided on the 02 axis.
A timing belt 602 for transmitting the driving force 03 to the driving roller 602 is a positioning stud provided at three locations on the rear plate of the photoconductor unit for positioning with the rear plate of the copying machine main body.

In the above, when the photosensitive belt 109 is running, the rotation of the drive motor 203 is controlled by the timing belt 6.
This is performed by transmitting the driving force to the driving roller 202 via the control unit 01. When setting the photoconductor unit in the copying machine main body, the photoconductor unit is set so that the positioning stud 602 of the photoconductor unit is fitted into the positioning hole formed in the rear plate of the copying machine. Thus, the positional accuracy of the photoconductor unit with respect to the copying machine is maintained.

FIG. 7 is a block diagram showing the tracking control of the photosensitive belt 109 described above. In the figure,
A tracking motor 701 controls ON / OFF of the tracking motor 310 based on a deviation detection signal of the OPC sensor 210, a sector detection signal of the sector detector 311 (rotation time of the deflection shaft 303), and a measurement value of the deviation time counter 702. The control unit 702 is a photosensitive belt 10
It is a shift time measurement counter that measures the shift time of 9
The measurement of the shift time of the photoreceptor belt 109 is executed after the copying of a predetermined number of sheets when the copying machine is started.

Here, the photosensitive belt 10 in this embodiment is
The tracking relationship of No. 9 will be described below. The sector plate 306 is designed for one rotation / 1 second. The eccentricity when the edge (semicircular end) of the sector plate 306 is detected by the sector detector 311 (at the time of maximum eccentricity) is one side.
It is about 0.8 mm (1.6 mm on both sides). Ma
At this time, the inclination angle of the belt correction roller 204 is maximum.
It has become. When the edge angle of the sector plate 306 is detected at a rotation angle of 0 °, the one-side eccentric amount Y when the sector plate 306 is rotated by + θ ° is given by the equation (1). [Equation 1] Y = 0.8 cos θ (where θ ≦ 360 °) As described above, θ and the rotation time of the sector plate 306 are in a proportional relationship. In other words, it indicates that when the inclination angle of the photosensitive belt 109 due to the shift of the photosensitive belt 109 increases, the shift correction time also increases. This indicates that the inclination angle of the photosensitive belt 109 can be controlled by controlling the deviation correction time.

One rotation / 1 sec = 360 ° / 1 sec
c, the time t required to rotate θ ° is given by Equation 2.
Is given by [Equation 2] t = 1/360 × θ ° (However, θ = 360 · t)

Therefore, the one-side eccentricity Y can be replaced by the following equation (3) from the equations (1) and (2). [Equation 3] Y = 0.8 cos (360 · t)

Here, for example, the deflection shaft 303 at this time is
If the amount of eccentricity is 0.4 mm, then 0.4 = 0.8 cos (360 · t) t ≒ 0.167 sec. Therefore, in the present embodiment, as shown in the flowchart below, the adjustment increase time of the shift time of the photosensitive belt 109 with respect to the predetermined time in the shift correction time is +0.1 s.
ec.

FIG. 8 is a flowchart showing the operation of the tracking control system of the photosensitive belt 109. In the figure, first, the shift time of the photosensitive belt 109 is measured by the shift time counter 702 (S801).

Next, the shift time from the left side to the right side is 15 seconds.
It is checked whether the value is equal to or less than ec (S802). At this time, if it is 15 seconds or more, it is subsequently checked whether the shift time from the right side to the left side is 15 seconds or less (S8).
03), if it is 15 seconds or longer, the normal deviation control is executed as it is (S804).

In step S802, if the shift time of the photosensitive belt 109 is 15 seconds or less, the shift time from the left side to the right side is adjusted (S805). This shift time adjustment is executed by increasing the ON time of the tracking motor 310 by +0.1 sec after detecting the edge of the sector plate 306 (S806). This results in a bell
The inclination angle of the correction roller 204 is smaller than the maximum value.
Therefore, the shift time of the photosensitive belt 109 becomes longer.

Next, the shift time from the left side to the right side is 15 seconds.
ec is confirmed again (S807), and
If it is longer than sec, the normal deviation control is executed as it is (S808). If it is determined in step S807 that the shift time of the photosensitive belt 109 is 15 seconds or less, the process returns to step S805 to execute the above operation.

If it is determined in step S803 that the shift time of the photosensitive belt 109 is 15 seconds or less, the shift time from the right side to the left side is adjusted (S809). This shift time adjustment is executed by increasing the ON time of the tracking motor 310 by +0.1 sec after detecting the edge of the sector plate 306 (S810). This results in a bell
The inclination angle of the correction roller 204 is smaller than the maximum value.
Therefore, the shift time of the photosensitive belt 109 becomes longer. Then, deviation time from the right side to the left side confirms whether a less 15sec again (S811), if more than 15sec, it performs normal lateral deviation control (S81
2). If it is determined in step S811 that the shift time of the photosensitive belt 109 is 15 seconds or less, the process returns to step S809 to execute the above operation. Thus, tilt
Change means, the measured shift time is 15 seconds or less
When the inclination angle of the belt correction roller 204 is larger than the maximum value,
Since it is changed to a small value, control is easy.
You. As a result, it is possible to easily correct the deviation of the photosensitive belt 109.
It can be performed reliably with the structure.

[0046]

As described above, the belt meandering correction device of the present invention is a belt meandering device provided with a belt correcting roller for correcting a belt shift caused by running the belt body by inclining in a direction opposite to the shift direction. in the modified apparatus, the base
The time it takes for the body to move from the right limit to the left limit,
It is also the time to move from the left limit to the right limit.
When the shift time of the belt member is less than the reference time, the belt correction roller is provided with a tilt changing means capable of changing the tilt angle of the belt correction roller to a value smaller than a maximum value. The above control can be performed, and it is possible to always perform highly reliable belt meandering correction by eliminating a problem in the photosensitive belt and the image forming unit due to an excessively short shift time. Further, the belt meandering correction device of the present invention, by the inclination changing means, when the deviation time of the belt body is less than the reference time, the inclination angle of the belt correction roller.
Since the change is made smaller than the maximum value , the control is simple. As a result, the deviation correction of the photoreceptor belt can be reliably performed with a simple structure.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a copying machine to which a belt meandering correction device of the present invention is applied.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a photoconductor unit according to the present invention.

FIG. 3 is an explanatory view showing a tracking mechanism of the photoconductor unit according to the present invention.

FIG. 4 is an explanatory view showing the principle of correcting the deviation of the photosensitive belt according to the present invention.

FIG. 5 is an explanatory view showing a belt tension mechanism of the photosensitive belt according to the present invention.

FIG. 6 is an explanatory diagram showing a driving unit of the photoconductor unit according to the present invention.

FIG. 7 is a block diagram illustrating tracking control of the photosensitive belt according to the present invention.

FIG. 8 is a flowchart showing an operation of a tracking control system of the photosensitive belt according to the present invention.

[Explanation of symbols]

109 Photosensitive belt 204 Belt correction roller 311 Sector detector 303 Deflection axis 310 Tracking motor 701 Tracking motor control unit 702 Offset time measurement counter

Claims (4)

(57) [Claims] 1. A belt shift generated during running of a belt body,
The belt meandering correction apparatus having a belt correction roller to correct the belt deviation tilts more direction opposite the
When the belt moves from the right limit to the left limit
And time to move from left limit to right limit
When the deviation time of the belt body is less than a reference time, the inclination angle of the belt correction roller is smaller than a maximum value.
Belt meandering correction apparatus comprising the gradient changing means capable of changing the have value. 2. The skew changing means includes: a deflecting shaft for generating a skew of the belt correction roller by rotation of an eccentric shaft;
A drive motor for driving said deflection axis, d of the belt body
Edge detecting means for detecting an edge, and the edge detecting means
Measuring means for measuring the deviation time of the belt member based on the detection signal, based on the reference time set time measured and advance by the measuring means, the drive motor O of
2. The belt meandering correction device according to claim 1, further comprising motor control means for performing N / OFF control. 3. When the shift time measured by the measuring means is shorter than a reference time, the ON time of the drive motor is increased by a predetermined value to make the inclination angle of the belt correction roller smaller than a maximum value. 3. The belt meandering correction device according to claim 2, wherein 4. A belt shift time measurement by said measuring means is measured for each shift direction of a belt body, and an ON time of said drive motor is increased by a predetermined value in response to each shift time, and said belt correction roller is turned on. 3. The belt meandering correction device according to claim 2, wherein the inclination angle is smaller than a maximum value .