JPH11249453A - Belt adjustment mechanism - Google Patents

Abstract

An object of the present invention is to provide a belt adjusting mechanism that can easily adjust the deviation of a conveyor belt and an image forming apparatus including the same. A belt is provided with a sensor at a reference position.
If C is on, it is offset to the left, and if sensor 25C is off, it is offset to the right. Here, the micro screw 21 is rotated by the motor 24 so that the sensor 25C moves in the direction of turning on when the sensor 25C is off, and moves in the direction of turning off the sensor 25C when the sensor 25C turns on, and stops once the belt 19 comes to the position of the sensor 25C. Let it. One rotation of the belt 19, the sensor 25L
Is turned on (whether the sensor 25R is turned off). If it does not turn on (off) 16 times, the position of the pointer of the strain gauge 13 is recorded as normal. On the other hand, if it is turned on (off), it is returned to the reference position, the time (the number of rotations) during that time is measured, and the adjustment amount of the micro screw 21 according to the measured value is read out from the table of the EEPROM to perform the adjustment. Repeat monitoring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt adjusting mechanism for preventing a belt of a conveyor belt unit from shifting, and an image forming apparatus provided with the same.

[0002]

2. Description of the Related Art Conventionally, there is a color image forming apparatus.
Some color image forming apparatuses perform color printing with one image processing unit, and others perform printing by arranging a plurality of image processing units in a multistage manner. One image processing unit that performs color printing uses three subtractive primary colors Y (yellow: yellow), M (magenta: red dye) and C (cyan: greenish blue) on one page of paper. ) Is transferred or printed by superimposing a total of four types of colorants of each color toner or ink (hereinafter, simply referred to as colorants) and Bk (black: black) colorants dedicated to printing characters and black portions. Since the printing (image forming) process is performed individually for each colorant, the printing process is repeated four times for one page of paper, and therefore the printing process takes a long time. On the other hand, when printing is performed by arranging a plurality of image processing units in a multi-stage manner, four processes are performed in one process.
Because the type of colorant is transferred or printed by superimposing sequentially on paper,
The processing speed is almost four times that of a single image processing unit that performs color printing. For this reason, in recent years,
A method of performing printing by arranging a plurality of image processing units in a multi-stage manner is often used.

[0003] In the case of performing printing by arranging such a plurality of image processing units in a multi-stage manner, a transport belt is often used for transporting paper. This is because the transport belt electrostatically attracts the paper and the position in the paper width direction is fixed,
This is because the paper is conveyed while being circulated in the vertical direction of the paper, so that the vertical and horizontal positions of the paper are kept constant, and thus stable conveyance is expected.

At present, the transport belt is unitized like other internal devices such as an image forming unit, and is provided as a transport belt unit in an image forming apparatus main body (hereinafter simply referred to as an apparatus main body). It is designed to be removably assembled.

If the unit frame of the conveyor belt unit is distorted, the balance of the tension of the conveyor belt with respect to the driving roller and the driven roller that support and drive the conveyor belt at both ends in the form of a loop may be subtle. For this reason, when the transport belt unit is assembled and driven in the apparatus main body, the transport belt is displaced and is shifted to one of the two.

[0006] Usually, in order to control the deviation, sticking members called beads are attached to the inner surfaces of the edges at both ends of the conveyor belt, or rollers (driving rollers, driven rollers, auxiliary rollers, etc.). The shaft is provided with a flange.

However, if the deviation of the conveyor belt as described above becomes large, a bead for preventing the deviation may ride on the peripheral surface of the roller, or a flange for preventing the deviation may be attached to the belt. Problems such as the end portion getting over occur. If this problem is left unattended, a problem occurs that the transport belt is eventually broken.

Conventionally, in order to solve such a problem, before assembling the transport belt unit to the apparatus main body,
The transport belt unit is driven by the test device, and the posture of the unit frame is finely adjusted while visually checking the operating state of the transport belt.

FIG. 10 is a perspective view schematically showing such a conveyor belt adjusting device. The conveyor belt unit 1 shown in FIG. 1 includes a left unit frame 2a and a right unit frame 2b, a driving roller 3 and a driven roller 4 supported by the unit frames 2a and 2b, and a driving roller 3 and a driven roller 4 And a transport belt 5 stretched to support both ends of the loop. When the transport belt unit 1 is mounted on the apparatus main body, the gear 6 of the drive roller 3 is engaged with the gear of the drive system on the apparatus main body side, and the transport belt 5 is set in a drivable state.

In the assembly process of the factory, as described above, the transport belt unit 1 is temporarily fixed to a test device (transport belt adjustment device) and driven before being assembled to the apparatus main body. In FIG. 1, the illustration of the temporary fixing table and the test drive system of the transport belt adjustment device is omitted, and only the adjustment unit 7 is shown. The adjusting unit 7 includes a torsion micro screw 8, a spur gear 8-1 fixed to the torsion micro screw 8, a pinion gear 9-1 meshing with the spur gear 8-1, and the pinion gear 9-1 at the shaft end. A motor 9 that is fixed and rotates in both forward and reverse directions is provided. The tip of the torsion micro screw 8 is
The right unit frame 2b is set so as to contact the lower surface of the end portion on the driven roller 4 side.

The test drive system of the transport belt adjusting device is operated, and the transport belt 5 is driven via the gear 6 and the drive roller 3.
Is driven to circulate. At this time, if the conveyor belt 5 is observed for a while and shows a deviation toward either the left unit frame 2a or the right unit frame 2b, the power of the motor 9 is turned on and the belt is rotated in either the forward or reverse direction. Then, the torsion micro screw 8 is rotated in either the forward or reverse direction via the pinion gear 9-1 and the spur gear 8-1.

As a result, the tip of the torsion microscrew 8 moves up or down, and the end of the right unit frame 2b on the driven roller 4 side slightly moves up and down. Thereby, the posture of the stretched surface between the driving roller 3 and the driven roller 4 of the transport belt 5 is twisted clockwise or counterclockwise, whereby the tension of the transport belt 5 is adjusted, and Is corrected. In this state, the entire unit frame is fixed (the horizontal frame orthogonal to the left unit frame 2a and the right unit frame 2b is not shown in the figure), and this is assembled to the apparatus main body.

[0013]

However, even if the transport belt of the transport belt unit is adjusted so that there is no deviation, distortion is generated in the unit frame when the transport belt unit is assembled to the apparatus main body. If this occurs, the above adjustments become useless, so that this assembly requires great care, is extremely mentally tiring, and is a major problem in efficiency.

[0014] Even if the assembly is successful,
If the use environment after shipment from the factory is not good, for example, when used on a table having unevenness or inclination on the installation surface, in recent years, in the image forming apparatus that is created mainly with light weight and small size, The internal main body frame is easily distorted due to such unevenness or inclination of the installation surface. When the main body frame is distorted, the conveyance belt unit is also distorted, and the above adjustments are canceled out. When the machine is actually operated, the conveyance belt, which should have been bent, is shifted again.

Therefore, it is necessary to perform readjustment after assembling into the apparatus main body. After assembling the conveyor belt unit into the apparatus main body, adjustment is performed while checking the deviation of the conveyor belt with the upper cover of the apparatus main body opened, but this adjustment work performed in a narrow space inside the apparatus main body is This was troublesome and inefficient work, and was a maintenance problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances,
An object of the present invention is to provide a belt adjustment mechanism that can easily adjust the deviation of a conveyor belt and an image forming apparatus including the same.

[0017]

The construction of the belt adjusting mechanism of the present invention and an image forming apparatus having the same will be described below.

First, the belt adjusting mechanism according to the first aspect of the present invention includes a plurality of rollers including a driving roller to which a driving force is transmitted from a driving source, a support frame for supporting both ends of the plurality of rollers, A transfer belt that is stretched between the plurality of rollers so as to be circulatingly movable to adsorb and transport the transfer material to the outer peripheral surface; and A belt adjustment mechanism for adjusting, wherein a bias of an end portion at the time of the belt circulating movement is adjusted by changing an attitude of the transfer belt with respect to the mounting section on which the transport belt unit is installed and the mounting section. Adjusting means; belt detecting means for detecting the position of the end of the transfer conveyance belt with respect to the conveyance belt unit; and a belt circulating movement speed based on detection information from the belt detection means. A deviation state calculating unit belt deviation calculates the relationship between the moving speed that is configured and control means for controlling to actuate said adjusting means on the basis of the calculation result of 該片 close state calculating means.

The adjusting means is disposed between the support frame and the mounting portion and deflects the support frame to move a predetermined portion of the support frame with respect to the mounting portion. It has a distortion mechanism. The distortion mechanism includes, for example, a moving member that is fixed to the mounting portion and moves the support frame by contacting the support frame, and a moving member driving mechanism that drives the moving member. And a moving member fixed to the mounting portion and abutting on the support frame to move the support frame, for example, as described in claim 4,
A manual operation mechanism for driving the moving member is provided.

Next, an image forming apparatus according to a fifth aspect supports an image forming section, a plurality of rollers including a driving roller to which a driving force is transmitted from a driving source, and both ends of the plurality of rollers. An image forming apparatus having a transfer belt unit detachably provided with a support frame and a transfer transfer belt stretched between the plurality of rollers so as to circulate and move so as to adsorb and transfer a transfer material to an outer peripheral surface. A mounting section for installing the transport belt unit, adjusting means for changing a posture of the transfer transport belt with respect to the mounting section, and a belt for detecting a position of an end of the transfer transport belt with respect to the transport belt unit Position detecting means, belt state calculating means for calculating a relationship between the belt circulating movement speed and the belt shift movement speed based on the detection information from the belt position detection means, The adjusting means is operated so as to change the attitude of the transfer conveyance belt with respect to the mounting portion in a direction for correcting the deviation of the end of the transfer conveyance belt during the belt circulation movement based on the calculation result of the state calculation means. Operation control means.

The operation control means is configured to control the adjustment means to be operated other than at the time of executing image formation, for example, as described in claim 6, and for example, as described in claim 8, A test mode capable of arbitrarily executing a series of belt adjustment controls for operating the belt position detecting means, the belt state calculating means, and the adjusting means is provided.

In this image forming apparatus, the transfer-conveying belt is driven on the basis of the driving source so that the belt circulating speed of the transfer / conveying belt is faster than the belt circulating speed at the time of executing image formation. There is further provided a belt circulation moving speed switching means for controlling the rotation of the driving roller at a high speed. The operation control means controls the belt circulation movement speed switching means to perform high-speed control during non-image formation, and activates the belt position detection means, the belt state calculation means, and the adjustment means. Also,
The image forming apparatus further includes a display unit that displays a calculation result of the belt state calculation unit in order to operate the adjustment unit.

The adjusting means may be, for example,
As described in Item 0, the apparatus comprises a distortion device disposed between the support frame and the mounting portion and distorting the support frame to move a predetermined portion of the support frame with respect to the mounting portion.

[0024] The distortion device may be, for example, a moving member fixed to the mounting portion for moving the support frame by contacting the support frame, and a moving member driving mechanism for driving the moving member. And a moving member fixed to the mounting portion and abutting the support frame to move the support frame, and a manual operation mechanism for driving the moving member. It becomes.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B are perspective views of the belt adjusting device according to the first embodiment.
(a) is a diagram showing the distortion measuring jig, and (b) is a diagram showing the adjusting mechanism together with the transport belt unit. FIG. 1 (b) has the same configuration as the belt adjusting mechanism shown in FIG. 10, and is different from the case of FIG. 10 in that the belt is not adjusted while visually checking the deviation of the conveyor belt. Is to adjust the conveyor belt unit to an appropriate state while automatically detecting the deviation speed of the conveyor belt.
Further, the distortion measuring jig of FIG. 1A records the state (distortion state) of the transport belt unit adjusted to the above-described proper state, and facilitates the adjustment after being assembled to the image forming apparatus main body. This is to end the process quickly and in a short time.

First, a strain measuring jig 10 shown in FIG.
Is a square frame-shaped measuring jig body 11, and three fixed measuring elements 12a, 12b, and 12c vertically protruding from three frame-shaped lower surfaces of the frame of the measuring jig body 11, respectively. A dial gauge (strain measuring device) 13 arranged on the upper surface of a corner portion having no fixed measuring element, and a dial gauge measuring element 13-1 protruding downward through the frame of the measuring jig body 11 from the dial gauge 13. Become.

On the other hand, the conveyor belt unit 15 shown in FIG. 2B has a left unit frame 16a, a right unit frame 16b, and these unit frames 16a and 16b.
A drive roller 17 and a driven roller 18 are supported by a shaft, and a transport belt 19 is supported by the drive roller 17 and the driven roller 18 so that both ends of the loop are supported. When the transport belt unit 15 is mounted on the apparatus main body, the gear 17-1 of the drive roller 17 is engaged with a drive system gear on the apparatus main body side, and the transport belt 19 is set in a drivable state.

Although not shown in FIG. 2B, the temporary fixing base of the adjusting mechanism 20 engages with the transport belt unit 15 and the transport belt unit 15 Is temporarily fixed, and the test drive system of the adjustment mechanism 20, also not shown, is engaged with the gear 17-1 of the transport belt unit 15 temporarily fixed.

The adjusting mechanism 20 includes a torsion micro screw 21,
A spur gear 22 fixed to the torsion micro screw 21, a pinion gear 23 meshing with the spur gear 22, a motor 24 fixed to the shaft end and rotating in both forward and reverse directions, and three more (Hereinafter simply referred to as sensors) 25L, 25C, and 25R, and further includes a control device (not shown).

The three fixed tracing styluses 12a, 12b and 12c of the above-described strain measuring jig 10 have tips protruding downward from the left unit frame 1 of the conveyor belt unit 15.
6a, the driven roller 18 side end, the drive roller 17 side end,
And the right unit frame 16b is placed in contact with the upper surface of the drive roller 17 side end. Then, the tip protruding below the dial gauge tracing stylus 13-1 is located on the upper surface of the end of the right unit frame 16b on the driven roller 18 side,
Contact freely.

The tip of the torsion micro screw 21 is set so as to contact the lower surface of the right unit frame 16b on the side of the driven roller 18 side. The three sensors 25L, 25C and 25R are connected to the transport belt 19
Is located at the reference position, a central sensor 25C is disposed at a position for detecting the side end of the conveyor belt 19, and the sensors 2C are spaced apart from each other by 0.25 mm to the left and right.
5L and a sensor 25R are arranged.

The control unit includes the three sensors 25L and 25L.
The outputs of C and 25R are monitored, and the motor 24 is rotated by a predetermined amount in either the forward or reverse direction based on these outputs. As a result, the torsion microscrew 21 rotates in either the forward or reverse direction via the pinion gear 23 and the spur gear 22, and its tip advances or retreats upward or downward, whereby the driven roller 18 of the right unit frame 16b is rotated. The position of the end on the side, that is, the position of the end where the dial gauge tracing stylus 13-1 is in contact moves slightly up or down. Thus, the transport belt 19 during the test drive can be shifted (adjusted) in any direction on the left or right.

For example, the rotation of the torsion microscrew 21 causes the end of the right unit frame 16b on the dial gauge 13 side to rise with the axis of the drive roller 17 as a fulcrum (the direction in which the dial gauge measuring element 13-1 is compressed). ), The conveyor belt 19 is shifted to the left unit frame 16a side, the torsion microscrew 21 rotates in the opposite direction to the above, and the dial gauge 13 side end of the right unit frame 16b descends (dial gauge). When the tracing stylus 13-1 moves in the direction in which the tracing stylus 13-1 extends, the transport belt 19 is shifted toward the right unit frame 16b.

Here, the amount of movement of the dial gauge tracing stylus 13-1 is proportional to the moving speed of the conveyor belt 19 (the amount of movement per time). And dial gauge probe 1
The movement amount of 3-1 can be read by the pointer of the dial gauge 13. If the moving speed of the transport belt 19 is too high, the friction between the side end portion of the transport belt 19 and the later-described non-stop restricting flange increases, and the transport belt 19 is damaged.

FIG. 2A is a diagram showing the relationship between the non-stop regulating flange provided on the rotating shaft of the driven roller 18 and the above-mentioned transport belt 19, which is not shown in FIG. 1B. FIG. 2B is a diagram showing a positional relationship between the three sensors 25L, 25C, and 25R with respect to the transport belt 19.

As shown in FIG. 2A, at both ends of the driven roller 18, stoppers (belt deviation preventing members) 26 having deviation preventing flanges 26-1 are provided.
A helical spring 27 is interposed between the stopper 26 and the left unit frame 16a (and the right unit frame 16b).

The stopper 26 allows a certain amount of deviation pressure of the conveyor belt 19, but if the deviation speed is high (the deviation pressure is strong), it cannot be restricted by the force of the helical spring 27, and the deviation prevention flange 26- 1 and conveyor belt 1
As a result, the conveyor belt 19 is damaged.

Therefore, it is necessary to set an allowable shift speed of the transport belt 19. In the present embodiment, as a result of various experiments using a belt having an outer peripheral length of 763.4 mm ± 0.5 mm, as shown in FIG.
While the transport belt 19 is circulating 16 times, the transport belt 1
It has been found that if the amount of movement (offset) of the periphery of No. 9 is within 0.25 mm, it is appropriate as an allowable offset speed. Therefore, in this example, this value is used as a standard for adjusting the deviation of the conveyor belt.

Then, as will be described later, the value of the dial gauge 13 within the above-mentioned adjustment standard is automatically searched, and the value of the dial gauge 13 obtained by the search is determined as a set value. When the set value is recorded and the conveyor belt unit 15 is incorporated into the apparatus main body, the value of the dial gauge 13 is adjusted so as to be the set value recorded above. This solves the problem of distortion when assembling the transport belt unit 15 into the apparatus main body, and improves work efficiency of assembling.

FIGS. 3 and 4 are flowcharts of the processing operation for automatically adjusting the attitude of the belt adjusting device having the above-described configuration with respect to the transport belt and displaying the optimum position. In this processing, although not particularly shown, the control unit uses a counter and a display device for counting the number of rotations (cycles of circulation movement) of the transport belt 19.

First, in FIG. 3, the controller prepares for adjustment (step S1). This process is a process of driving the three sensors 25L, 25C, and 25R, for example. Next, referring to the output of each sensor (step S2),
It is determined whether or not the sensor 25C is on (detects the end of the conveyor belt) (step S3). If the sensor 25C is on (Y in S3), the transport belt 19
Left unit frame 1 from the center position which is a proper position
6a.

In this case, the motor 24 is driven to move the torsion micro screw 21 via the pinion gear 23 and the spur gear 22 in a direction in which the tip thereof is lowered (in a direction in which the transport belt 19 is recalled to the right unit frame 16b side). After the large rotation (step S4), the transport belt 19 is driven via a motor (not shown) and its drive transmission system and a gear 17-1 engaged with the motor (step S5).

Subsequently, referring to the output of each sensor (step S6), it is determined whether or not the sensor 25C is turned off (the end of the conveyor belt is not detected) (step S7). Repeat until 25C turns off. When the sensor 25C is turned off (Y in S7), the drive system of the transport belt 19 is immediately stopped (step S7).
8). As a result, the transport belt 19 stops at the proper central position, that is, the reference position for the adjustment to be performed.

Next, in this state, the conveyor belt 19 remains in a state of being recalled to the right unit frame 16b side. In order to cancel the recall state, the torsion microscrew 21 is moved in a direction in which the tip thereof rises. After the rotation (step S9), the process proceeds to an adjustment process described later (step S10).

On the other hand, when the sensor 25C is off in step S3 (N in S3), this means that the transport belt 19 is shifted from the center position to the right unit frame 16b side. Is torsion micro screw 2
1 is largely rotated in the direction in which the tip thereof rises (the direction in which the transport belt 19 is recalled to the left unit frame 16a side) (step S11), and then the transport belt 19 is rotated in the same manner as described above.
Is driven (step S12).

Subsequently, referring to the output of each sensor (step S13), it is determined whether or not the sensor 25C is turned on (detecting the end of the conveyor belt) (step S14). Repeat until turned on. When the sensor 25C is turned on (Y in S14), the drive system of the transport belt 19 is stopped at that moment (step S15). Thereby, also in this case, the transport belt 19
Stops at a central position where should be correct, i.e., a reference position for adjustments to be made.

In this case, since the state in which the conveyor belt 19 is recalled to the left unit frame 16a side is continued, in order to cancel the recalled state, the torsion microscrew 21 is moved in a direction in which the tip thereof is lowered. After the rotation (step S16), the process proceeds to step S10 of the adjustment process.

Subsequently, in step S10 of the adjustment process, as shown in the detailed flowchart of FIG.
9 is driven to make one rotation (step S101). Next, referring to the output of each sensor (step S102), first, the sensor 25R is turned off (the end of the transport belt 19 is moved from the reference position by 0.2 to the right unit frame 16b side).
5 mm or more) (Step S)
103).

If the sensor 25R has not been turned off (N in S103, the conveyor belt 19 is being detected), it is next determined whether or not the sensor 25L has been turned on (step S104). If the sensor 25L is off (N in S104), the counter is incremented by "1" (step S105), and the value of the counter is displayed on the display device (step S106).

Subsequently, referring to the value of the counter, it is determined whether or not the value is "16" (step S).
107). If the value of the counter is less than "16" (N in S107), it is determined that the predetermined observation period has not yet elapsed, and the process returns to step S101 to repeat steps S101 to S107.

On the other hand, if the value of the counter is "16", the initial setting is maintained even after the period of 16 rotations of the conveyor belt 19 (the posture observation period of the conveyor belt set in this example) has elapsed. From the set reference position, no deviation of 0.25 mm or more has occurred on either side of the left unit frame 16a or the right unit frame 16b.
Therefore, in this case, it is determined that the conveyance belt 19 is maintaining the proper posture, the counter is cleared to "0" and reset (step S108), and the display device indicates that the adjustment of the conveyance belt is completed. (Step S10
9), the adjustment processing ends.

As described above, the transport belt is first set at the reference position, and is rotated for a predetermined period (in this example, a time of 16 rotations). If there is no deviation of 0.25 mm or more in any direction, it is normal. It is determined that there is, and the adjustment ends.

However, if the sensor 25L is turned on in step S104 (Y in S104), this means that the conveyor belt 19 is moved to the left unit frame 16a side within a relatively short time from the initially set reference position. 0.25
mm, and in this case, it is determined that the value exceeds the allowable belt deviation value, and the process proceeds to the adjustment processing in steps S110 to S117. After this transition, first, the torsion micro screw 21 is largely lowered (Step S110), and the transport belt 19 is driven (Step S111).

Subsequently, referring to the output of each sensor (step S112), it is determined whether or not the sensor 25C has been turned off (step S113).
Repeat until 5C turns off. When the sensor 25C is turned off (Y in S113), the drive system of the transport belt 19 is stopped at that moment (step S114). As a result, the transport belt 19, which has been displaced in the direction of the left unit frame 16a at a speed equal to or higher than the allowable value, returns to the center reference position again and stops.

Here, the torsion microscrew 21 rotated in the lowering direction is rotated in the raising direction so as to return upward by the lowered amount (step S115), and the value of the counter is referred to (step S116). ). At this time, the value of the counter is determined by the number of rotations of the conveyor belt 19 at which the sensor 25C is turned off, that is, the number of rotations of the conveyor belt 19 returns from the shifted position to the reference position. Is recorded.

The control unit confirms the count number, and rotates the torsion microscrew 21 once returned in the upward direction in the downward direction by an amount corresponding to the confirmed count number of the counter (step S117). Then, the content of the counter is cleared to "0" and reset (step S118), and the process returns to the 16-round observation process of steps S101 to S109 described above.

The reason why the torsion micro screw 21 is rotated in the downward direction by an amount corresponding to the count number of the counter is to make the count value of the counter correspond to the rotation speed of the motor 24 (or the rotation speed of the torsion micro screw 21). It is stored in advance in a ROM or the like of the control unit as a numerical value table. Also,
If the sensor 25R is turned off in the above step S103 (Y in S103), this means that the conveyor belt 19 is moved to the right unit frame 16b side by 0.25 mm or more within a relatively short time from the initially set reference position. In this case, it is determined that the allowable deviation value of the belt is exceeded.
The process proceeds to the adjustment process at S127. In the processing after this transition, first, the torsion micro screw 21 is greatly raised (step S120), and the transport belt 19 is driven (step S120).
121).

Subsequently, referring to the output of each sensor (step S122), it is determined whether or not the sensor 25C is turned on (step S123).
Repeat until is turned on. Then, if the sensor 25C is turned on (Y in S123), the transport belt 1 is
The drive system of No. 9 is stopped (step S124). As a result, the right unit frame 16 is moved at a speed higher than the allowable value.
The transport belt 19 shifted in the direction b returns to the center reference position again and stops.

Next, the torsion microscrew 21 rotated in the raising direction is rotated in the lowering direction so as to be lowered by the raised amount (step S125). Then, the count value is referred to (step S126). In this case, the value of the counter is determined by the number of rotations of the transport belt 19 at which the sensor 25C is turned on, that is, the number of rotations of the transport belt 19 returns from the deviated position to the reference position. Is recorded.

The control unit confirms the count number, and rotates the torsion micro screw 21 once returned in the down direction in the up direction by an amount corresponding to the confirmed count number of the counter (step S127). , The aforementioned step S
From 118, the process returns to the 16-turn check processing of steps S101 to S109.

The rotation of the torsion micro screw 21 in the upward direction by an amount corresponding to the count number of the counter is performed by associating the count value of the counter with the rotation speed of the motor 24 (or the rotation speed of the torsion micro screw 21). It is stored in advance in a ROM or the like of the control unit as a numerical value table.

As described above, when the deviation of the conveyor belt from the reference position is 0.25 mm or more within the predetermined period,
The conveyor belt is once returned to the reference position, the return time is measured, the torsion micro screw 21 is rotated according to the measured return time, and the excessive rotation of the torsion micro screw 21 temporarily set for return is performed. The amount is corrected and the 16-lap observation process is repeated. If the rotation of the torsion microscrew 21 is excessive, a leftward shift is detected in step S104, and the rotation is more slowly performed in steps S110 to S117. If the corrected amount is still excessive, the deviation to the right is detected again in step S103, and it is repeated that the correction is made more gently in steps S120 to S127. Eventually, no deviation will be observed even after the rotation of the conveyor belt has passed the 16th lap, and it has been adjusted so that the normal posture can be maintained for a long period of time. That.

As described above, the deviation speed of the conveyor belt is detected, the characteristic of the deviation amount of the conveyor belt is found based on the detected speed, and the movement is adjusted in accordance with the found characteristic of the deviation amount. As a result of this movement adjustment, when the deviation time becomes equal to or more than a certain value (the deviation speed is slow), it can be determined that the posture of the transport belt has become appropriate.

At this time, the torsion micro screw 21
Can be read by the pointer of the dial gauge 13. That is, even after the lapse of the period of 16 rounds of the transport belt, the position of the torsion micro screw 21 in which the deviation of the transport belt is within 0.25 mm can be automatically found.

After recording the position of the pointer and mounting the conveyor belt unit 15 on the apparatus main body, the dial gauge 13
If the fixed measuring elements 12a, 12b, 12c and the dial gauge measuring element 13-1 are brought into contact with the conveyor belt unit 15 and the position of the unit frame is adjusted while looking at the hands, it is necessary to test rotate the conveyor belt. Not
The distortion of the unit frame after mounting can be easily corrected.

In the above example, the torsion micro screw 21
Is driven by a motor, but is not limited thereto, and may be rotated by a manual mechanism. In addition, even after the above adjustment, it is conceivable that the transport belt is shifted to the left or right from the reference position for an elapsed time of 16 or more laps. If it is equal to or more than 16 turns, the deviation pressure is small even if it is one-sided, so that the stopper (belt deviation prevention member) 26 can be sufficiently restrained by the deviation prevention flange 26-1.

The adjusting mechanism 20 is incorporated in the apparatus main body, and while the output of the sensor 25 is monitored by the control device of the apparatus main body, the torsion micro screw 21 is rotated by using the power of the apparatus main body. By adjusting the posture of the conveyor belt by raising and lowering the corners of the unit frame, the adjustment of the conveyor belt is further facilitated. This will be described below as a second embodiment.

FIG. 5 is a side sectional view showing the structure of an image forming apparatus having a belt adjusting mechanism according to the second embodiment. As shown in the figure, the image forming apparatus is a tandem type full color printer. This full-color printer (hereinafter, also referred to as an apparatus main body) 30 has a front surface (left side in the figure).
An openable paper feed tray 32 is provided above, a paper cassette 33 detachable from the front is provided below, and an upper cover 3 is provided on the upper surface.
4 is provided.

A large number of sheets are placed and stored in the sheet cassette 33 described above. An operation unit including a power switch (not shown), a liquid crystal display device, and a plurality of input keys (not shown) is disposed on the front side of the upper cover 34. The upper cover 34 is provided with a paper discharge stopper 35 at a front part, and a rear part forms an upper paper discharge tray 36 with a rear upper surface of the main unit 30.

Inside the main body device 30, a transport belt 37 formed in a flat loop shape in the front and rear direction is disposed substantially at the center with the transport surface horizontal, and a tension roller 31 is pressed against the back surface at the lower part of the loop. ing. Thus, the transport belt 37 is stretched and supported between the drive roller 38 and the driven roller 39, driven by the drive roller 38, and circulates clockwise in FIG. Above the conveyor belt 37, 4
Image forming units 40 (40a, 40b, 40c,
40d) are arranged side by side in a multi-stage manner along the paper transport direction of the transport belt 37 (from left to right in FIG. 5).

These image forming units 40 (hereinafter, only the devices of the image forming unit 40a are numbered and shown) have a photosensitive drum 41 and a photosensitive drum 4
Various devices such as a charger 42, a developing device 43, a developing roller 44, and a cleaner 45 are assembled around the peripheral surface of the device 1. The four photoconductor drums 41 are connected to the transport belt 37.
Are arranged in contact with the upper circulation portion (sheet transport surface). Magenta, cyan, yellow, and black color toners are accommodated in the housings of the developing devices 43 of the image forming units 40a to 40d, respectively.

An exposure head 47 disposed on the back surface of the upper lid 34 via a support member 46 is disposed between the charger 42 and the developing device 43. The exposure head 47 descends with the closing of the upper lid 34 and faces the photosensitive drum 41, where an image recording section is formed. The developing roller 44 is rotatably supported by the lower opening of the housing of the developing device 43 and is in pressure contact with the photosensitive drum 41 to form an image developing section there.

Further, the transfer brush 48 is
The transfer brush 48 is disposed in contact with the back surface of the upper
And an image transfer portion is formed here. These image recording unit, image developing unit, and image transfer unit form an image forming unit as a whole.

A standby roll pair 49 is disposed upstream of the transport belt 37 in the paper transport direction, and a paper sensor 50 is disposed upstream thereof. Further, the upstream side is branched laterally and downwardly, and a paper feed roller 51, a separating member 52, and the above-described openable / closable paper feed tray 32 are provided in the horizontal direction. A feed path 53 composed of two guide plates is formed below, and a pair of transport rolls 54 is disposed at the upstream (lower) end thereof. positioned. Above the paper feed end of the paper feed cassette 33, a paper feed roller 55 having a half-moon cross section is disposed.

On the other hand, a belt adjusting mechanism 60 similar to that shown in FIG. 1B is arranged downstream of the conveyor belt 37 in the sheet conveying direction so as to engage with the belt unit. A sheet separation claw 56 is disposed in contact with the transport belt 37, and a fixing unit 57 is disposed downstream thereof. The fixing unit 57 includes a heat fixing roller pair including a heating roller and a pressing roller in a heat insulating housing, a fixing unit separating claw that presses against the heating roller, an oil application roller, and the like.

Downstream of the fixing section 57, a pair of paper discharge rolls 58 and a switching lever 59 are provided behind the pair. A rear paper outlet 61 is formed behind the switching lever 59, and a paper discharging path 62 is formed above the switching lever 59. At the end of the paper discharging path 62, a paper discharging roller 63 and a paper discharging roller 64 are provided. Is formed above the rear portion of the upper paper discharge tray 36.

Further, an electrical unit 65 is provided between the transport belt 37 and the sheet cassette 33 at a position rearward from the center of the inside. A predetermined number of substrates on which electronic circuits forming a control unit are mounted are mounted on the electrical unit 65.

The transport belt 37 is used to drive the driving roller 3
8, the driven roller 39, the tension roller 31, and the transfer brush 48 are unitized similarly to the transport belt 19 shown in FIG.

FIG. 6 is a front sectional view showing an arrangement state of the belt unit in the main unit. As shown in FIG. 6, the belt unit 66 is supported by an auxiliary frame 67, and the auxiliary frame 67 is integrally attached to a frame 68 of the apparatus main body 30.

The above-described drive roller 38 and driven roller 39
(In FIG. 6, the drive roller 38 in front of the figure and the driven roller 39 on the opposite side of the figure are not visible because of the sectional view.) The tension roller 31 and the like are supported by the belt unit 66 and supported by the auxiliary frame 67. . In addition, the transport belt 3
The photosensitive drum 41 is disposed on the upper surface of the conveyor belt 37 so as to face the transfer brush 48 that is in sliding contact with the upper back surface of the transfer belt 7. The photosensitive drum 41 is supported by a sub-frame 69 of the apparatus main body.

FIG. 7 is a diagram showing a system configuration of a control unit formed on the substrate of the electrical unit 65. As shown in FIG. As shown in the figure, the color printer 30 includes an I / F controller 7.
0, a printer controller 71, and various load units 72. Print data is input to the I / F controller 70 from the host computer 73. The I / F controller 70 analyzes the print data output from the host computer 73 and creates dot pattern data to be output to each of the exposure heads 47 described above. This I / F controller 7
A display unit 74 made of a liquid crystal or the like is connected to 0.

The printer controller 71 has a CPU 75,
ROM 76, EEPROM 77, LED head controller 7
8, a driver 79 and a buffer 80.
The CPU 75 is a color printer 30 according to the present embodiment.
The entire system is controlled, and control is performed according to a program stored in the ROM 76.

The CPU 75 has sensors 25L, 25C and 2 of the belt adjusting mechanism 20 incorporated in the apparatus main body.
Information is input from various sensors 81 including 5R via a buffer 80, and based on this information, the CPU 75
Print processing is executed in accordance with the program stored in the storage unit 76, and, on the other hand, based on an adjustment instruction or the like input from the operation unit via a key, adjustment processing of the transport belt 37, which will be described in detail later, is executed.

The LED head controller 78 converts the print data of yellow (Y), magenta (M), cyan (C) and black (Bk) output from the I / F controller 70 into various load units corresponding thereto. 72 exposure heads 4
7 (LED heads 47a, 47b, 47c, 47d).

The driver 79 drives various devices of the various load units 72 other than the LED head. The fixing rollers 82 of these devices are a heat generating roller and a pressing roller of the fixing unit 57, and the rotational drive transmitted from the drive motor via a gear train is connected and disconnected by a clutch.

The high-voltage power supply 83 is a power supply for supplying a bias voltage to the charger 42, the developing roller 44, the transfer brush 48, and the like.
4. A motor for rotationally driving the paper feed roller 51 and the like, and the pulse motor 85 is a motor for rotationally driving the paper feed roller 55, the photosensitive drum 41, the fixing roller and the like.

The developing clutch 86 transmits the rotation of the DC motor 84 or the pulse motor 85 to all four image processing units (in the case of full-color printing) or only to the black (Bk) image processing unit ( (For monochrome printing). The belt vertical motor 87 is
A motor that rotates a cam (not shown) that moves the transport belt 37 up or down according to the print mode of the full-color printing or the monochrome printing.

When the upstream side of the transport belt 37 is moved downward by the drive of the belt up / down motor 87, only the photosensitive drum 41 of the most downstream image forming unit 40d is brought into pressure contact with the transport belt 37 to enable monochrome printing. It is configured to be. The state of the transport belt 37 shown in FIG. 5 indicates a state where all the photosensitive drums 41 are in contact with the transport belt 37 and full-color printing is possible.

The belt adjustment motor 88 is the motor 24 of the belt adjustment mechanism 20. The paper feed clutch 89 is a clutch for rotating the paper feed roller 55 intermittently, that is, one rotation per sheet. And the standby clutch 9
Numeral 0 denotes a clutch for stopping the standby roller pair 49 or rotating it in synchronization with the printing timing.

Subsequently, the full-color printer 3 having the above configuration
The processing operation of 0 will be described. First, normal printing processing will be described. The full-color printer 30 starts printing (printing) when the power is turned on and the number of sheets to be used, the printing mode, and other designations are input as a key input or a signal from a connected host device.

First, the paper feed roller 55 makes one rotation to take out one uppermost sheet stored in the paper cassette 33 and feed it to the standby roll pair 49 via the feed path 53. Alternatively, the paper feed roller 51 feeds the paper placed on the open / close paper feed tray 32 to the standby roll pair 49 in cooperation with the separating member 52.

The paper sensor 50 detects the leading edge of the fed paper. The standby roll pair 49 temporarily stops rotating to stop the paper from advancing, and waits for the transport timing. The drive roller 38 rotates clockwise to start the circulating movement of the transport belt 37. Each image forming unit 40 is sequentially driven in accordance with the printing timing, and the photosensitive drum 41 rotates counterclockwise.

The charger 42 applies a uniform high negative charge to the peripheral surface of the photosensitive drum 41 and initializes the same.
Performs exposure corresponding to the image signal on the peripheral surface of the photosensitive drum 41. As a result, an electrostatic latent image composed of a high negative potential portion due to the initialization and a low negative potential portion due to the exposure is formed on the photosensitive drum 41. The developing roller 44 transfers the toner in the developing device 43 to the low potential portion of the electrostatic latent image to form a toner image on the peripheral surface of the photosensitive drum 41 (reversal development).
I do.

The image forming unit 4 at the uppermost stream in the paper transport direction
At the timing when the leading end of the magenta toner image on the peripheral surface of the photosensitive drum 41 is rotated and conveyed to the portion facing the conveyor belt 37, the standby position is set so that the print start position of the paper coincides with the opposing portion. The roll pair 49 starts rotating and feeds the paper toward the transport belt 37. The sheet is transported by the transport belt 37 to the first image transfer section formed by the photosensitive drum 41 and the transfer brush 48.

The transfer brush 48 transfers the transfer current output from the transfer bias power supply of the high voltage power supply
To transfer the magenta toner image on the photosensitive drum 41 of the image forming unit 40a to the sheet. Subsequently, the photosensitive drum 4 of the image forming unit 40b is
The first and second image transfer units from the upstream in the sheet conveyance direction by the transfer brush 48 transfer the cyan toner image, and further, the photosensitive drum 41 and the transfer brush 48 of the image forming unit 40c.
Transfers the yellow toner image to the photosensitive drum 4 of the image forming unit 40d.
1 and the lowermost image transfer portion by the transfer brush 48 transfers the black toner image.

The paper on which the toner images of the four colors have been transferred in a superposed manner is separated from the transport belt 37 by the paper separating claws 56 and is carried into the fixing section 57. The fixing unit 57 presses and holds the sheet with an appropriate force between the heating roller and the pressing roller, and applies heat and pressure to the sheet to discharge the toner image backward while fixing the toner image on the sheet.

The sheet discharged from the fixing section 57 is nipped by a pair of sheet discharge rolls 58 and is carried over, and when the switching lever 59 is rotated downward as shown in FIG.
The toner image is guided upward along the paper discharge path 62, is further inverted forward at the end, and is discharged onto the upper paper discharge tray 36 with the toner image facing downward from the upper paper discharge port. Alternatively, when the switching lever 59 is pivoted upward, the rear discharge port 61
Is discharged out of the apparatus with the image surface facing upward.

In the above-described full-color printer 30 that operates as described above, when a belt adjustment instruction is input by a key from the operation unit, the adjustment of the transport belt 37 is started. FIG.
FIG. 9 is a flowchart of a processing operation for automatically adjusting the conveyor belt according to the second embodiment.
This processing is performed by the CPU 7 of the printer controller 71.
5 is performed. In this process,
A counter area for counting the number of rotations of the conveyor belt 37 (cycle of circulation movement) is provided in the EEPROM 77. Also,
The EEPROM 77 has a count value for rotating the torsion micro screw 21 of the belt adjustment mechanism 20 built in the apparatus main body up or down by an amount corresponding to the count number of the counter, as will be described later. A correspondence table with the number of rotations is stored.

First, in FIG. 8, the controller prepares for adjustment (step M1). This process is a process of driving the three sensors 25L, 25C, and 25R, for example. Next, referring to the output of each sensor (step M2),
It is determined whether or not the sensor 25C is on (detects the end of the conveyor belt) (step M3). If the sensor 25C is on (M3 is Y), the transport belt 19
It may be shifted to the left from the center position, which is an appropriate position (see FIG. 2B).

In this case, first, it is determined whether or not the apparatus main body 30 is performing printing (step M4). If printing is in progress (M4 is y), the process waits until printing is completed. Then, when printing is completed (M4 is n), printing is prohibited to perform belt adjustment (step M5). In this process,
For example, the switch of the operation unit for instructing the start of printing is locked, and the display unit 74 displays "print prohibition" or "setting the belt adjustment mode".

Subsequently, the belt adjusting motor 87 is driven to rotate the torsion micro screw 21 via the pinion gear 23 and the spur gear 22 of the belt adjusting mechanism 20 in the direction in which the tip of the micro screw 21 is lowered (the transport belt 37 is moved to the right side). Direction to call back)
Then, the pulse motor 85 is driven to circulate the transport belt 37 (step M7).

Subsequently, referring to the output of each sensor (step M8), it is determined whether or not the sensor 25C is turned off (the end of the conveyor belt is not detected) (step M9). Repeat until 25C turns off. Then, when the sensor 25C is turned off (M9 is y), the drive system of the transport belt 37 is immediately stopped (Step M).
10). As a result, the transport belt 37 stops at the proper center position (reference position for adjustment).

Next, in order to release the above setting for returning the transport belt 37 to the right side, that is, to return the torsion microscrew 21 to the state before the lowering, the torsion microscrew 21 is rotated in the direction in which the tip rises. After that (step M11), the print permission state is set (step M11).
12), and proceed to an adjustment process described later (step M1)
3). The setting of the print permission state is, for example, a process of unlocking a switch of an operation unit for instructing the start of printing and displaying “print OK” on the display unit 74.

On the other hand, if the sensor 25C is off at step M3 (M3 is n), there is a possibility that the conveyor belt 37 is shifted to the right from the center position.
Also in this case, first, it is determined whether or not the apparatus main body 30 is performing printing (step M14). If printing is being performed (M14 is y), the process waits until printing is completed. Then, when printing is completed (M14 is n), next, in order to perform belt adjustment,
The switch of the operation unit for instructing the start of printing is locked, and the display unit 74 displays “print prohibition” or “belt adjustment mode is being set” or the like to prohibit printing (step M1).
5).

Subsequently, the belt adjusting motor 87 is driven to rotate the torsion microscrew 21 through the pinion gear 23 and the spur gear 22 of the belt adjusting mechanism 20 in the direction of raising the tip thereof (the transport belt 37 is moved to the left side). Direction to call back)
Then, the pulse motor 85 is driven to circulate the transport belt 37 (step M17).

Subsequently, referring to the output of each sensor (step M18), it is determined whether or not the sensor 25C is turned on (detecting the end of the conveyor belt) (step M19). Repeat until turned on. Then, when the sensor 25C is turned on (M19 is y), the drive system of the transport belt 37 is immediately stopped, and thereby the transport belt 37 is stopped at an appropriate central position (reference position for adjustment) ( Step M20).

Then, in order to cancel the above setting for recalling the transport belt 37 to the left side, that is, in order to return the torsion microscrew 21 to the state before the large raising, the torsion microscrew 21 is rotated in a direction in which the tip is lowered. After that (step M21), the processing shifts to the processing of step M12 and thereafter.

Subsequently, in step M13 of the adjusting process, as shown in the detailed flowchart of FIG.
7 is driven to make one revolution (step M101). Next, referring to the output of each sensor (step M102), first, the sensor 25R is turned off (the end of the transport belt 37 is shifted to the right by 0.25 mm or more from the reference position).
It is determined whether or not (Step M103).

If the sensor 25R has not been turned off (M103 is N, the conveyor belt 37 is being detected), it is next determined whether or not the sensor 25L has been turned on (step M104). If the sensor 25L is off (M104 is N), the counter is incremented by "1" (step M105), and the value of the counter is displayed on the display device (step M106).
Return to 1.

As described above, when the conveyor belt 37 does not deviate from the reference position by more than 0.25 mm on either side, the outputs of the sensors 25R and 25L are monitored.
Only the counting of the number of rotations of the transport belt 37 and the display thereof are repeatedly performed. Note that the display may simply display a message such as "belt OK" instead of the number of rotations of the transport belt.

On the other hand, in step M104, the sensor 2
When 5L is turned on (M104 is y), this indicates that the conveyor belt 37 has deviated 0.25 mm or more to the left from the above-described reference position, and in this case, exceeds the allowable belt deviation value. It is determined that the
The processing shifts to the adjustment processing of 0 to S119.

That is, first, it is determined whether or not the apparatus main body 30 is performing printing (step M110). If printing is in progress (M110 is y), the process waits until printing is completed. Then, when printing is completed (M110 is n), the printing start switch is locked to perform belt adjustment, "printing prohibited" is displayed on the display unit 74, and printing is set. (Step M111), the torsion microscrew 21 is largely lowered (Step M112), and the transport belt 37 is driven (Step M113).

Subsequently, referring to the output of each sensor (step M114), it is determined whether or not the sensor 25C has been turned off (step M115).
Repeat until 5C turns off. When the sensor 25C is turned off (M115 is y), the transport belt 3 is immediately turned off.
7 is stopped (step M116). Thereby, the transport belt 37 returns to the central reference position and stops.

Here, the torsion microscrew 21 rotated in the lowering direction is rotated in the raising direction so as to return upward by the lowered amount (step M117), and the transport belt 37 is moved with reference to the value of the counter. The number of rotations from when the belt is driven to when it is stopped, that is, until the conveyor belt 37 returns from the shifted position to the reference position is checked (step M).
118).

Then, the drive amount of the torsion micro screw 21 corresponding to the above-mentioned rotation speed is read from the table stored in the EEPROM 77, and the torsion micro screw 21 once returned in the raising direction by the read drive amount is read. It is rotated in the lowering direction (step M119). As a result, the tendency of the conveyor belt 37 to the left side detected in step M104 is corrected.

Thereafter, steps M130 and M1 described above are performed.
31 is performed, and steps M101 to M106 are performed again.
Return to the monitoring position. If the sensor 25R is turned off in step M103 (M103 is y), the conveyance belt 37 moves 0.25 mm to the right from the reference position.
This indicates that it is approaching. Also in this case, it is determined that the value exceeds the belt deviation allowable value, and the process proceeds to step M1.
The processing shifts to the adjustment processing of 20 to S129.

In this case, first, it is determined whether or not the apparatus main body 30 is printing (step M120). If printing is being performed (M120 is y), the process waits until printing is completed. Then, when printing is completed (M120 is n), the printing start switch is locked to perform belt adjustment, "printing prohibition" or the like is displayed on the display unit 74, and printing prohibition is set. (Step M121), the torsion microscrew 21 is greatly increased (Step M122), and the transport belt 37 is driven (Step M123).

Subsequently, referring to the output of each sensor (step M124), it is determined whether or not the sensor 25C has been turned off (step M125).
The operation is repeated until the sensor 5C is turned off. When the sensor 25C is turned off (M125 is y), the drive system of the conveyor belt 37 is immediately stopped (Step M116). Thereby, the transport belt 37 returns to the central reference position and stops.

Next, the torsion microscrew 21 rotated in the raising direction is rotated in the lowering direction so as to be lowered by the raised amount (step M127), and the transport belt 37 is moved with reference to the counter value. The number of rotations from when the belt is driven to when it is stopped, that is, until the conveyor belt 37 returns from the shifted position to the reference position is checked (step M1).
28).

Then, the drive amount of the torsion micro screw 21 corresponding to the rotation speed is read from the table stored in the EEPROM 77, and the torsion micro screw 21 once returned in the lowering direction by the read drive amount is read out. It is rotated in the raising direction (step M129). Thus, the rightward tendency of the conveyor belt 37 detected in step M103 is corrected.

Thereafter, steps M130 and M1 described above are performed.
31 is performed, and steps M101 to M106 are performed again.
Return to the monitoring position. As described above, in the second embodiment, when the belt adjustment mode is specified by incorporating the belt adjustment mechanism 20 into the full-color printer 30, the shift direction and the shift speed of the transport belt are determined by the three sensors 25. The adjustment amount is determined in accordance with the detected deviation speed, and the determined adjustment amount is determined by the torsion micro screw 21.
To set the conveyor belt unit. This allows
The posture of the conveyor belt is always maintained correctly.

In the adjustment processing of steps M112 to M119 or steps M122 to M129, since printing is prohibited, step M113 or step M123 is performed.
Since the rotation of the transport belt 37 driven by the above does not affect other devices directly related to printing, the drive of the transport belt 37 at this time may be controlled so as to be faster than usual. Then, the deviation speed increases in proportion to the rotation speed of the transport belt, and the adjustment time can be reduced.

Further, the description has been made assuming that the instruction for belt adjustment is input by a key from the operation unit. However, the present invention is not limited to this. The above-described belt adjustment processing may be automatically performed at the time of idling. It may be performed at the time of maintenance service. Further, it may be automatically performed when the transport belt moves, such as when changing between color printing and monochrome printing.

[0124]

As described above in detail, according to the present invention, when adjusting the conveyor belt by the conveyor belt unit alone, the shift speed of the belt is observed and compared with a preset reference value. Since the adjustment is performed, the deviation of the belt can be automatically determined and adjusted without visual observation, so that the work efficiency of the belt adjustment in the assembly process is improved.

Further, since the same belt adjustment mechanism is incorporated in the main body of the image forming apparatus, automatic adjustment of the belt in real time can be performed in real time for a belt state defect due to environmental changes such as elongation of the belt and a change in the installation surface of the main body. Therefore, a troublesome maintenance work for adjusting the belt, which is performed by opening the upper cover, is not required, thereby providing an image forming apparatus that always operates stably.

[Brief description of the drawings]

FIGS. 1A and 1B are perspective views of a belt adjusting mechanism according to a first embodiment, and FIG. 1A is a view showing a strain measuring jig;
(b) is a diagram showing the adjusting mechanism together with the transport belt.

FIG. 2A is a diagram illustrating a relationship between a non-conventional restriction flange provided on a rotating shaft of a driven roller and a transport belt;
(b) is a diagram showing the positional relationship of three sensors with respect to the conveyor belt.

FIG. 3 is a flowchart (part 1) of a processing operation for automatically adjusting the attitude of the belt adjusting device with respect to the transport belt and displaying an optimum position.

FIG. 4 is a flowchart (part 2) of a processing operation for automatically adjusting the attitude of the belt adjusting device with respect to the transport belt and displaying an optimum position.

FIG. 5 is a side sectional view illustrating a configuration of an image forming apparatus including a belt adjusting mechanism according to a second embodiment.

FIG. 6 is a front sectional view showing an arrangement state of the belt unit in the main body device.

FIG. 7 is a diagram illustrating a system configuration of a control unit formed on a substrate of an electrical unit.

FIG. 8 is a flowchart (part 1) of a processing operation for automatically adjusting the conveyance belt according to the second embodiment.

FIG. 9 is a flowchart (part 2) of a processing operation for automatically adjusting the transport belt according to the second embodiment.

FIG. 10 is a perspective view schematically showing a conventional conveyor belt adjusting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Conveyor belt unit 2a Left unit frame 2b Right unit frame 3 Drive roller 4 Follower roller 5 Conveyor belt 6 Gear 7 Adjustment part 8 Twist micro screw 8-1 Spur gear 9 Motor 9-1 Pinion gear 10 Strain measuring jig 11 Measurement jig Tool body 12a, 12b, 12c Fixed measuring element 13 Dial gauge (strain measuring instrument) 13-1 Dial gauge measuring element 15 Conveyor belt unit 16a Left unit frame 16b Right unit frame 17 Driving roller 17-1 Gear 18 Follower roller 19 Conveying belt REFERENCE SIGNS LIST 20 adjustment mechanism 21 torsion micro screw 22 spur gear 23 pinion gear 24 motor 25 L, 25 C, 25 R sensor 26 stopper (belt deviation prevention member) 26-1 deviation prevention flange 27 spiral spring 30 full color printer 31 ten Roller roller 32 Open / close paper feed tray 33 Paper cassette 34 Upper lid 35 Paper discharge stop 36 Upper paper discharge tray 37 Conveyor belt 38 Drive roller 39 Follower roller 40 (40a, 40b, 40c, 40d) Image forming unit 41 Photoconductor drum 42 Charger 43 Developing device 44 Developing roller 45 Cleaner 46 Supporting member 47 (47a, 47b, 47c, 47d) Exposure head (LED head) 48 Transfer brush 49 Standby roll pair 50 Paper sensor 51 Paper feed roller 52 Separation member 53 Feed path 54 Transport roll Pair 55 Paper feed roller 56 Paper separation claw 57 Fixing unit 58 Paper discharge roll pair 59 Switching lever 60 Belt adjustment mechanism 61 Rear paper discharge port 62 Paper discharge path 63 Paper discharge roller 64 Paper discharge roller 65 Electrical unit 66 Belt unit 67 Auxiliary frame 68 frame 69 sub Arm 70 I / F controller 71 Printer controller 72 Various load units 73 Host computer 74 Display unit 75 CPU 76 ROM 77 EEPROM 78 LED head control unit 79 Driver 80 Buffer 81 Various sensors 82 Fixing roller 83 High voltage power supply unit 84 DC motor 85 Pulse Motor 86 Developing clutch 87 Belt up / down motor 88 Belt adjustment motor 89 Paper feed clutch 90 Standby clutch

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masafumi Hirano 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Inside Casio Electronics Co., Ltd. (72) Inventor Shigeki Kimura 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Electronics Industries (72) Inventor Hajime Iwakawa 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Electronics Co., Ltd.

Claims (12)

[Claims] A plurality of rollers including a driving roller to which a driving force is transmitted from a driving source; a support frame for supporting both ends of the plurality of rollers; A transfer conveyance belt stretched between the plurality of rollers so as to be capable of circulating movement, and a belt adjustment mechanism that adjusts the bias of the conveyance belt unit to an end portion during the belt circulation movement, the conveyance belt unit comprising: A mounting section on which a unit is installed; adjusting means for adjusting a deviation of an end portion during the belt circulating movement by changing a posture of the transfer belt with respect to the mounting section; and the transfer transport with respect to the transport belt unit. Belt detecting means for detecting the position of the end of the belt, and calculating the relationship between the belt circulating moving speed and the belt skew moving speed based on the detection information from the belt detecting means. Belt adjustment mechanism, characterized in that it comprises a deviation state calculating means, and control means for controlling to actuate said adjusting means on the basis of the calculation result of 該片 close state calculating means. 2. The apparatus according to claim 1, wherein the adjusting unit includes a distortion mechanism disposed between the support frame and the mounting unit, and distorting the support frame to move a predetermined portion of the support frame with respect to the mounting unit. The belt adjustment mechanism according to claim 1, wherein: 3. The distortion mechanism includes a moving member fixed to the mounting portion and moving the support frame by contacting the support frame, and a moving member driving mechanism driving the moving member. The belt adjusting mechanism according to claim 2, wherein 4. The distortion mechanism includes a moving member fixed to the mounting portion and moving the support frame by contacting the support frame, and a manual operation mechanism for driving the moving member. 3. The belt adjusting mechanism according to claim 2, wherein: 5. An image forming section, a plurality of rollers including a driving roller to which a driving force is transmitted from a driving source, a support frame supporting both ends of the plurality of rollers, and a transfer material adsorbed on an outer peripheral surface. An image forming apparatus, comprising: a transfer belt unit having a transfer belt stretched between the plurality of rollers so as to be circulatingly movable so that the transfer belt unit can be transported. A mounting unit, an adjusting unit that changes an attitude of the transfer conveyance belt with respect to the mounting unit, a belt position detection unit that detects a position of an end of the transfer conveyance belt with respect to the conveyance belt unit, and a belt position detection unit. State calculating means for calculating the relationship between the belt circulating movement speed and the belt skew moving speed based on the detected information of the belt, and based on the calculation result of the belt state calculating means. Operation control means for operating the adjusting means so as to change the attitude of the transfer conveyance belt with respect to the mounting portion in a direction to correct the deviation of the end of the transfer conveyance belt during the belt circulation movement. Characteristic image forming apparatus. 6. The image forming apparatus according to claim 5, wherein the operation control unit controls the adjustment unit to operate at a time other than when image formation is performed. 7. A belt circulating movement speed switching means for controlling the rotation of the driving roller based on the driving source at a high speed so that the belt circulating movement speed of the transfer / conveying belt is faster than the belt circulating movement speed during image formation. The apparatus further includes: the operation control unit controls the belt circulation movement speed switching unit to perform high-speed control during non-image formation, and activates the belt position detection unit, the belt state calculation unit, and the adjustment unit. The image forming apparatus according to claim 5, wherein: 8. The operation control means includes a test mode capable of arbitrarily executing a series of belt adjustment controls for operating the belt position detection means, the belt state calculation means, and the adjustment means. Claim 5
The image forming apparatus as described in the above. 9. The image forming apparatus according to claim 5, further comprising display means for displaying a calculation result of said belt state calculation means to operate said adjustment means. 10. The apparatus according to claim 1, wherein the adjusting means is provided between the support frame and the mounting portion, and comprises a distortion device for distorting the support frame to move a predetermined portion of the support frame with respect to the mounting portion. The image forming apparatus according to claim 5, wherein: 11. The distortion device includes a moving member fixed to the mounting portion and moving the support frame by contacting the support frame, and a moving member driving mechanism for driving the moving member. The image forming apparatus according to claim 10, wherein 12. The distortion device according to claim 1, further comprising a moving member fixed to the mounting portion and moving the supporting frame by contacting the supporting frame, and a manual operating mechanism for driving the moving member. The image forming apparatus according to claim 5, wherein: