JP2009086448A - Belt deviation amount measuring device, belt driving device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring belt deviation, which is not restricted in a layout and can calculate a belt deviation without causing any false detection due to variation in belt speed, and to provide a belt driving device and an image forming apparatus. <P>SOLUTION: The device for measuring belt deviation includes: the belt 102 with marks formed on a surface; an irradiating means 111 irradiating the marks with light; a light receiving means 112 receiving reflected light from the marks; a specifying means for specifying the quantity of the reflected light from the marks in the received reflected light; and a calculating means for calculating the belt deviation based on the amount of variation in the reflected light quantity by the mark 102 which is specified by the specifying means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a belt shift amount measuring device, a belt drive device, and an image forming apparatus that calculate a belt shift amount.

  In a belt driving device that drives a belt supported by a plurality of rotating bodies, it is generally ideal that the belt is conveyed in the driving direction, but the inclination of the rotating body that constitutes the driving system, The belt may meander or drive due to differences in tension between the left and right sides, if the belt is an endless belt, the difference in the circumference of the belt itself, or the electrophotographic intermediate transfer belt or heat fixing belt due to fluctuations in the external load due to paper entry, etc. It is known that there is a phenomenon that approaches a direction different from the direction.

  Thus, it is known to calculate the shift amount based on a change in timing of receiving reflected light from the mark. However, in this case, since the timing changes also depending on the belt speed fluctuation, it is difficult to distinguish between the belt shift and the belt speed fluctuation. Therefore, the following techniques have been proposed.

In Patent Document 1, by setting the circumference of the belt to an integral multiple of the circumference of the drive roll, the influence of the belt surface speed by the drive roll on the meandering detection of the belt is the same every rotation. In addition, a method of detecting an accurate shift amount by processing a speed fluctuation pattern of one rotation drive roll by a low-pass filter or the like has been proposed.
Japanese Patent No. 3084588

  However, the above means has the following problems.

  By making the ratio of the circumference of the drive roll and the belt circumference an integer ratio, the influence on the meandering detection of the belt speed fluctuation caused by the drive roll becomes the same every rotation, so that it can be corrected. However, there is a problem that the diameter of the drive roll and the belt circumference can be restricted, the layout of the drive roll other than the belt is restricted, and the apparatus cannot be downsized.

  An object of the present invention is to provide a belt shift amount measuring device, a belt drive device, and an image forming apparatus that calculate a belt shift amount that is free from layout limitations and that does not cause erroneous detection due to speed fluctuations. Is to provide.

  In order to achieve the above object, the invention according to claim 1 is configured to receive a belt having a mark formed on a surface thereof, an irradiating unit that irradiates the mark, a light receiving unit that receives reflected light from the mark, and a light receiving unit. Belt deviation amount measurement comprising: specifying means for specifying the amount of reflected light by the mark from reflected light; and calculating means for calculating the amount of deviation of the belt based on the amount of change in the amount of reflected light by the mark specified by the specifying means. It is a device.

  According to a second aspect of the present invention, in the belt deviation amount measuring apparatus according to the first aspect, the calculating means is a change amount in which the amount of light reflected by the same mark on the belt changes with each rotation period of the belt. Based on the above, the deviation amount of the belt is calculated.

  According to a third aspect of the present invention, in the belt deviation amount measuring apparatus according to the first or second aspect, the belt has a plurality of different marks in the transport direction, and the calculation means includes different marks on the belt. The amount of deviation of the belt is calculated based on the amount of change in which the amount of reflected light varies.

  According to a fourth aspect of the present invention, in the belt deviation amount measuring apparatus according to any one of the first to third aspects, the light receiving unit includes a plurality of light receiving units, and the plurality of light receiving units At least one receives reflected light from the mark, at least one of the plurality of light receiving units directly receives irradiation light from the illumination unit, and the calculation unit is based on the directly received irradiation light. The belt shift amount is corrected.

  According to a fifth aspect of the present invention, there is provided a belt obtained from the roller that rotates the belt, an actuator that changes the inclination of the roller, and the belt deviation amount measuring device according to any one of the first to fourth aspects. The belt driving device includes: a calculation unit that calculates a movement amount of the actuator based on a shift amount; and a control unit that drives the actuator based on the movement amount to correct the shift of the belt.

  According to a sixth aspect of the present invention, there is provided an image forming apparatus including the belt deviation amount measuring device according to any one of the first to fourth aspects.

  A seventh aspect of the present invention is an image forming apparatus including the belt driving device according to the fifth aspect.

  According to the present invention, it is possible to provide a belt deviation amount measuring device, a belt driving device, and an image forming apparatus that calculate a belt deviation amount that does not have layout restrictions and does not cause erroneous detection due to speed fluctuations.

  The present invention has the following aspects.

The amount of deviation of the belt is calculated based on the amount of change in the amount of reflected light from the mark.
That is, since the shift amount is not calculated based on the change in timing of receiving the reflected light from the mark, the influence of the belt speed fluctuation is reduced.

The amount of deviation of the belt is calculated based on the amount of change in the amount of light reflected by the same mark on the belt for each belt rotation period.
That is, since the shift amount is not calculated based on the change in timing of receiving the reflected light from the mark, the influence of the belt speed fluctuation is reduced.

The amount of deviation of the belt is calculated based on the amount of change in the amount of light reflected by a plurality of different marks in the belt conveyance direction.
That is, since the shift amount is not calculated based on the change in timing of receiving the reflected light from the mark, the influence of the belt speed fluctuation is reduced.

  Further, according to the present invention, since there are a plurality of light receiving portions and the light amount change and the reflected light amount of the light source are simultaneously detected, the detection can be performed accurately without being affected by the light amount fluctuation of the light source.

  Moreover, the present invention enables highly accurate belt shift control.

  In addition, since the shift amount is not calculated based on the change in the timing of receiving the reflected light from the mark, the image forming apparatus can reduce the influence of the belt speed fluctuation.

  Further, since the shift amount is not calculated based on the change in the timing of receiving the reflected light from the mark, the influence of belt speed fluctuation is reduced, and the image forming apparatus capable of highly accurate belt shift control.

The belt deviation amount measuring apparatus, belt driving apparatus, and image forming apparatus having the above-described aspects will be described using the following embodiments.
The following terms can be constructed and modified by those skilled in the art within the scope not departing from the gist, with various modifications and substitutions.

  FIG. 1 is a schematic diagram showing an outline of a specific example of a four-tandem full-color image forming apparatus equipped with a belt deviation measuring apparatus according to Embodiment 1 of the present invention.

  The image forming apparatus 10 shown in the figure includes a driving roller 104, three rollers such as two driven rollers 105, a belt 102, four photosensitive members 101, a first transfer member 103, a second transfer member 106, and a belt shift measurement. The device 108 is configured. The belt 102 is a resin belt.

A drive motor (not shown) is attached to the drive roller 104. The driving roller 104 is driven by this motor, and the belt 102 is driven by transmitting a driving force to the belt 102. Further, the amount of deviation of the belt 102 is detected by a belt deviation measuring device 108 which is a non-contact displacement meter.

  In the image forming / transferring mechanism section in the quadruple tandem full-color image forming apparatus 10, an electrostatic image is formed on the photoconductor 101 and becomes a visible image with toner. This toner image is transferred to the belt 102 by the photoconductor 101 and the first transfer member 103.

  The belt 102 is held and driven by a driving roller 104 and a driven roller 105.

  Then, the toner image transferred to the belt 102 is transferred to the paper 107 by the second transfer member 106 to form an image on the paper.

  When a color shift phenomenon occurs when the color images of the respective colors are superimposed on the belt 102, the belt 102 moves to either side different from the driving direction. As a result, the superposition positions of the four colors are irregularly shifted. For example, assuming that there is 300 mm from the transfer position of the leftmost photoconductor 101 to the belt to the transfer position of the rightmost photoconductor 101, the belt shift is 0.1% (ratio of the shift amount to the travel distance). If there is, there will be a color shift of 300 μm, which is an unacceptable value in terms of image quality.

  FIG. 2 is an enlarged view of a main part in the vicinity of the belt deviation measuring device 108 of FIG.

  The belt-shift measuring device 108 includes a light irradiation unit 111 and a light receiving sensor (light receiving unit) 112, and is disposed in the vicinity of the belt 102. The belt offset measuring device 108 operates and operates by irradiating the pattern (mark) 110 formed on the belt 102 with light from the light irradiation means 111 and detecting the reflected light amount by the light receiving sensor 112. Is done.

  FIG. 3 is a diagram showing the relationship between the pattern 110 on the belt 102 shown in FIG. 2, the illumination by the light irradiation means 111 and the light receiving sensor 112, and the light receiving range. The amount of light reflected by the pattern 110 varies depending on the degree of overlap between the pattern 110 on the belt 102 and the area of the light receiving range.

  The amount of deviation of the belt is measured by measuring the change in the amount of light.

  FIG. 4 shows the sensor output that varies depending on the overlapping degree of the area of the light receiving area with the pattern 110 on the belt 102 shown in FIG. When the left light receiving range entirely overlaps the optical pattern 110, the sensor output is maximized. When the right light receiving range entirely overlaps a part of the optical pattern 110, the sensor output is low. When the light receiving range shown in the center overlaps the optical pattern 110 by about half, the sensor output is medium.

  FIG. 5 shows an algorithm for calculating a belt shift amount.

  The specifying unit 210 and the calculating unit 211 start calculating the belt shift amount (step 201). As processing performed by the specifying unit 210, after the belt 102 is driven and starts running at a constant speed, the light irradiation unit 111 irradiates the pattern 110 with light, and the light reception sensor 112 detects the amount of reflected light. Perform (step 202). If the edge of the pattern 110 is detected in step 202 (step 202 / YES), the specifying unit 210 specifies and stores the peak value of the reflected light amount (step 203). If not detected (step 202 / NO), the process does not proceed. After the processing of step 203, the calculation unit 211 calculates the shift amount from the difference between the peak value stored this time by the specifying unit 210 and the peak value stored last time (step 204).

  FIG. 6 is a graph showing the correlation between the sensor output change of the light receiving sensor 112 and the belt shift amount.

  The horizontal axis indicates the sensor output change amount, and the vertical axis indicates the belt shift amount, indicating the correlation.

  The calculating unit 211 has a table corresponding to this graph, and calculates the shift amount from the difference between the peak value stored this time by the specifying unit 210 and the peak value stored last time.

  FIG. 7 shows the sensor output from the light receiving sensor 112.

  The horizontal axis represents time, and the vertical axis represents the sensor output value.

  7A shows the sensor output in the pattern 110, and A ′ in the figure shows the sensor output in the pattern 110 after one round of the belt 102, and the deviation amount of the belt is calculated based on the difference between the outputs of A ′ and A. The

  In addition, Example 2 is the same as Example 1 except the content demonstrated below.

  FIG. 8 shows a plurality of optical patterns on the belt according to the second embodiment.

In the left figure, patterns A, B, and C are arranged as a pattern 110 on the belt 102 with a certain interval in the conveying direction of the belt 102.
The figure on the right shows the positional relationship between the range of the pattern 110 and the illumination and light receiving ranges as the patterns A, B and C on the belt.

  FIG. 9 is an enlarged view of a main part in the vicinity of the belt shift measuring device 108 of FIG. 1 according to the second embodiment.

  The belt offset measuring device 108 operates and operates by irradiating the patterns A, B, and C formed on the belt 102 with light from the light irradiation means 111 and detecting the amount of reflected light by the light receiving sensor 112. Is done.

  FIG. 10 illustrates sensor output from the light receiving sensor 112 according to the second embodiment.

  A, B, and C in the figure indicate sensor outputs in patterns A, B, and C, and A ′, B ′, and C ′ in the figure indicate sensor outputs in patterns A, B, and C after one round of the belt 102. Yes.

  FIG. 11 shows a first belt deviation measurement algorithm according to the second embodiment.

  In the flowchart at the bottom in FIG. 11, the specifying unit 210 detects the output A in the first pattern A (step 221). Thereafter, the output B in the first pattern B is detected (step 222). Next, the output C in the first pattern C is detected (step 223). Thereafter, the detected outputs A, B, and C are stored, and the specifying unit 210 detects the output A ′ in the second pattern A ′ (step 224). Then, the output B ′ in the second pattern B ′ is detected (step 225). Further, the output C ′ in the second pattern C ′ is detected (step 226). Then, the detected outputs A, B, and C are stored. Finally, the calculation unit 211 calculates a shift amount from A′-A, B′-B, and C′-C.

  The algorithm in the flowchart described above is shown in the upper part of FIG. 11 as a timing chart.

  FIG. 12 illustrates a second belt deviation measurement algorithm according to the second embodiment, and illustrates the relationship between the sensor output and the difference output.

  The calculation unit 211 calculates the shift amount from B-A, C-A, and A′-A, which are the differential outputs shown in FIG. Actually, B-A and C-A, which are differential outputs, substantially correspond to variations in the pattern installation position, and do not indicate a deviation amount. In the present embodiment, the deviation amount is calculated from the detection information of the same pattern every belt revolution.

  Thereby, even if the installation positions of the plurality of patterns are not accurate, it is possible to detect the belt shift amount from the front circumference when the patterns A to C come to the measuring instrument positions.

  That is, the detection value of each pattern one cycle before is used as a reference, and the shift amount is A′-A or B′-B to the last.

  For example, when the number of belt revolutions n is used, (An)-(An-1) is the amount of belt deviation when the pattern A in the nth round comes to the measuring instrument position.

  Furthermore, since the belt driving time between the patterns A to C becomes the minimum sampling time of the shift amount, the more the number of patterns (the shorter the interval), the more detailed the belt shift behavior can be grasped.

  In addition, Example 3 is the same as Example 1 except the content demonstrated below.

  FIG. 13 shows a light receiving means according to the third embodiment.

  The light receiving means includes a condensing lens 121 in addition to the light receiving sensor 112. The reflected light from the pattern 110 on the belt 102 enters the light receiving sensor 112 through the condenser lens 121.

  FIG. 14 illustrates an output of the light receiving sensor according to the third embodiment.

  The light receiving sensor 112 output of the edge part of the pattern 110 is shown. The horizontal axis represents time, and the vertical axis represents sensor output.

  When the condensing lens 121 is provided, the maximum level of the light receiving sensor 112 output is lower because of the amount of reflected light in a limited area as compared with the case without the condensing lens 121, but the light receiving sensor at the edge portion of the pattern 110. The rise of 112 output becomes sharp.

  FIG. 15 shows a light receiving means and an irradiating means according to a modification of the third embodiment. The irradiating means includes a light branching means 122 in addition to the light irradiating means 111. The light receiving sensor 112 includes a light receiving surface A 112a and a light receiving surface B 112b as a plurality of light receiving portions.

  The light emitted from the light irradiating means 111 is the light that reaches the light receiving surface A 112 a by the light branching means 122 and the surface of the belt 102 that is irradiated from the light irradiating means 111 and passes through the light branching means 122 and includes the pattern 110. , And is reflected by the condenser lens 121 and reaches the light receiving surface B112b. The light detected by the light receiving surface A 112 a can detect the original light amount change of the light irradiation means 111. By correcting the reflected light amount based on the original light amount change, it is possible to accurately detect the reflected light amount change from the surface of the belt 102 provided with the pattern 110.

  In addition, Example 4 is the same as Example 2 except the content demonstrated below.

  FIG. 16 illustrates a belt driving apparatus according to the fourth embodiment. This is a device in which a belt shift control mechanism is arranged in the apparatus of FIG. 9 according to the second embodiment. The belt shift control mechanism includes an actuator 131 that changes the inclination of the roller 105.

  When the belt deviation amount is detected by the belt deviation amount measuring apparatus having the light irradiation means 111 and the light receiving sensor 112, a calculation means (not shown) calculates the movement amount of the actuator 131 based on the belt deviation amount. A control unit (not shown) controls the shift of the belt 102 by tilting the actuator 131 disposed on the roller 105 based on the calculated movement amount.

  FIG. 17 illustrates a belt shift control algorithm according to the fourth embodiment.

  The calculating means 211 calculates the amount of belt deviation per round (step 231). Thereafter, the control means performs shift control based on the shift amount (step 232). Next, the control means calculates the effect of shift control (step 233). Further, the control means executes correction based on the shift control effect (step 234). By repeating the above operation, the deviation amount of the belt 102 can be controlled.

  FIG. 18 illustrates an image forming apparatus according to the fourth embodiment.

  This is one in which a belt shift control mechanism using an actuator 131 is mounted on the image forming apparatus of FIG.

  FIG. 19 shows an arrangement example 1 of the light receiving sensors according to the fourth embodiment.

  In this case, since the light receiving sensor 112 is arranged with respect to the belt 102 on the roller 105, it is difficult to receive disturbances such as vibration of the belt 102, and the detection accuracy of the light receiving sensor 112 is improved.

  FIG. 20 shows an arrangement example 2 of the light receiving sensors according to the modification of the fourth embodiment.

  The image forming apparatus 10 includes a plate member 132 on the back side of the belt 102 with respect to the light receiving sensor 112. In this case, since the light receiving sensor 112 is disposed with respect to the belt 102 on the plate member 132, the light receiving sensor 112 is less susceptible to disturbances such as vibration of the belt 102, and the detection accuracy of the light receiving sensor 112 is improved.

1 shows a configuration of an image forming apparatus equipped with a belt deviation measuring mechanism according to a first embodiment. The principal part enlarged view of the belt deviation measuring mechanism which concerns on Example 1 is shown. The optical pattern on the belt which concerns on Example 1, the illumination by a light irradiation means and a light receiving sensor, and the relationship of the light-receiving range are shown. The sensor output which fluctuates | varies with the extent which the pattern based on Example 1 and the area of a light-receiving range overlap is shown. 2 shows an algorithm for calculating a belt shift amount according to the first embodiment. The correlation of the sensor output which concerns on Example 1, and a belt deviation | shift amount is shown. The output by the light receiving sensor which concerns on Example 1 is shown. 2 shows a plurality of optical patterns on a belt according to a second embodiment. The principal part enlarged view of the belt deviation measuring mechanism which concerns on Example 2 is shown. The output by the light receiving sensor which concerns on Example 2 is shown. 10 shows a first belt deviation measurement algorithm according to the second embodiment. 10 shows a second belt deviation measurement algorithm according to the second embodiment. 6 shows a light receiving means according to a third embodiment. The output of the light-receiving means which concerns on Example 3 is shown. 7 shows a light receiving means and an irradiating means according to a modification of the third embodiment. 10 shows a belt drive device side control mechanism according to a fourth embodiment. 10 illustrates a belt shift control algorithm according to a fourth embodiment. 9 illustrates an image forming apparatus belt-shift measuring mechanism according to a fourth embodiment. An arrangement example of the light receiving sensor according to the fourth embodiment is shown. The example of arrangement | positioning of the light receiving sensor which concerns on the modification of Example 4 is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 20 Condensing lens apparatus 101 Photoconductor 102 Belt 103 1st transfer member 104 Drive roller 105 Followed roller 106 2nd transfer member 107 Paper 108 Belt deviation measuring apparatus 110 Pattern 111 Light irradiation means 112 Light receiving sensor 121 Condensing lens 122 Optical branching means 131 Actuator 132 Plate member

Claims (7)

A belt with a mark formed on the surface;
Irradiating means for irradiating the mark;
A light receiving means for receiving reflected light from the mark;
A specifying means for specifying the amount of light reflected by the mark from the received reflected light;
A belt deviation amount measuring apparatus, comprising: a calculation unit that calculates the deviation amount of the belt based on a change amount of a reflected light amount by the mark specified by the specification unit.   The said calculating means calculates the deviation | shift amount of the said belt based on the variation | change_quantity from which the reflected light quantity by the same mark on the said belt changes for every rotation period of the said belt. Belt offset measuring device. The belt has a plurality of different marks in the transport direction,
The belt deviation amount measuring apparatus according to claim 1, wherein the calculation unit calculates the deviation amount of the belt based on a change amount in which the amount of reflected light by different marks on the belt changes. The light receiving means has a plurality of light receiving portions,
At least one of the plurality of light receiving parts receives reflected light from the mark,
At least one of the plurality of light receiving units directly receives irradiation light from the illumination unit,
The belt deviation amount measuring apparatus according to any one of claims 1 to 3, wherein the calculation unit corrects the deviation amount of the belt based on the directly received irradiation light. A roller that wraps around the belt;
An actuator for changing the inclination of the roller;
Calculation means for calculating a movement amount of the actuator based on a belt deviation amount obtained from the belt deviation amount measuring device according to any one of claims 1 to 4,
And a control means for driving the actuator based on the amount of movement to correct the deviation of the belt.   An image forming apparatus comprising the belt shift amount measuring device according to claim 1.   An image forming apparatus comprising the belt driving device according to claim 5.

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