JP2001145380A - Abnormal motor stop device and detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To swiftly detect abnormal rotation of a motor when the motor is started or in steady state, and stop the motor. SOLUTION: The abnormal motor stop device contains set number-of-pulses for abnormal motor judgment storing means C5a1 and C6a1 that store the numbers of pulses for abnormal motor judgment set for the rotational speed detection pulses produced by a rotational speed detection pulse generator EN1 during the rotation of a motor, and maximum allowable time set value storing means C5a2 and C6a2 that store maximum allowable times required for detecting the set number of pulses after a reference time T0 determined according to the time of outputting a motor start signal. The abnormal motor stop device is also provided with abnormal start judging means C5a and C6a that, when the set number of pulses are not detected in the maximum allowable time, judge as abnormal rotation of the motor, and an abnormal stop means C2a at start of motor that, if an abnormal motor rotation is judged, stops the motor M2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor abnormality detecting device, and more particularly, to a motor abnormality detecting device configured to immediately stop driving a motor when there is an abnormality when starting the motor. The motor abnormality detection device is suitably used in a drive control device for a motor that rotates a member (for example, a photoconductor, a developing roll, or an intermediate transfer belt of an image forming apparatus) that rotates while being in contact with each other.

[0002]

2. Description of the Related Art The following technologies (1) and (2) are conventionally known as general motor abnormality detection devices. (1) Technology described in Japanese Patent Application Laid-Open No. H10-276950 This publication discloses that a traveling motor of a self-propelled vacuum cleaner that operates in a situation where no one is around is used to determine a minimum frequency value and a maximum frequency value of an encoder output pulse. A technique is described in which a setting is made, and if the frequency is out of the range, it is determined that there is an abnormality and the traveling motor is stopped. (2) Technology described in Japanese Patent Application Laid-Open No. H5-197032 discloses an optical system driving device that detects a state of rising settling (a stable scanning speed has been reached at the time of starting optical scanning of a document). In the case of a failure, a technique for stopping the optical system or warning the occurrence of a failure is described.

[0003]

(Problems of the prior arts (1) and (2)) In the prior art (1), since the frequency is detected, it takes time to detect an abnormality. Further, the prior art (2) is a technique in which the mirror base unit is stopped when the mirror base unit is moved from the home position to the leading end of the original document and is not settled when the motor is started. take time. That is, in the above-described conventional techniques (1) and (2), it is impossible to quickly detect an abnormality at the time of starting the motor. For this reason, when used as a drive control device for a motor that rotates one of the members that rotate while contacting each other (for example, a photoconductor of an image forming apparatus, a developing roll, or an intermediate transfer belt), one member that contacts each other During normal rotation, if the other member is not rotating or is rotating abnormally (slow rotation), it rotates with frictional contact. In this case, wear occurs due to frictional contact, so that there is a problem that the life of the rotating member is shortened.

The present invention has been made in view of the above circumstances, and has the following (O0
1) and (O02) are to be described. (O01) To promptly detect a motor rotation abnormality at the time of starting the motor or at a steady state. (O02) To shorten the time required for two members rotating in contact with each other to rotate in frictional contact when the rotation of the motor is abnormal.

[0005]

Means for Solving the Problems Next, the present invention for solving the above-mentioned problems will be described. Elements of the present invention are described in order to facilitate correspondence with the elements of the embodiments described later. The sign of parentheses is added in parentheses. The reason why the present invention is described in correspondence with the reference numerals of the following embodiments is to facilitate understanding of the present invention, and not to limit the scope of the present invention to the embodiments.

(First Invention) A motor abnormality stop device according to a first invention is characterized by having the following constituent elements (A01) to (A04). (A01) A motor drive circuit (D2, D4) for outputting motor drive power to the motors (M2, M4) in response to the output of a motor start signal which is a rotation start signal of the motors (M2, M4) for rotating the rotating members. , (A02) the motor (M
2, M4), a rotation speed detection pulse generator (EN1, M2) generates a rotation speed detection pulse (R) having a frequency corresponding to the rotation speed of the motor (M2, M4).
EN2), (A03) the number of rotation speed detection pulses (R) generated by the rotation speed detection pulse generators (EN1, EN2) after a reference time T0 determined according to the output time of the motor start signal is Set pulse number (R
1, R2), the maximum allowable time (T
M1a, TM2a) and a maximum permissible time setting value storage means (C5a2, C6a2) for storing the set number of motor abnormality determination pulses (R1, R2) within the maximum permissible time (TM1a, TM2a). Motor start abnormality determination means (C5a, C6a) for determining that the motor rotation is abnormal when the detection pulse (R) is not detected. (A04) Abnormal motor stopping means (C2a, C4) for stopping the motors (M2, M4) when the motor starting abnormality determining means (C5a, C6a) determines that the motor rotation is abnormal.
a).

(Operation of the First Invention)
In the motor abnormal stop device of the present invention, the motor drive circuit (D
, D4) are motors (M2, M
The motor driving power is output to the motors (M2, M4) according to the output of the motor start signal which is the rotation start signal of 4). The rotation speed detection pulse generator (EN1, EN2)
When the motors (M2, M4) rotate, the motors (M
2, M4) generates a rotation speed detection pulse (R) having a frequency corresponding to the rotation speed. The maximum permissible time setting value storage means (C5a2, C6a2) stores the rotation speed detection pulses generated by the rotation speed detection pulse generators (EN1, EN2) after a reference time T0 determined according to the output time of the motor start signal. The maximum allowable time (TM1a, TM2a) required for the number of (R) to become the set number of motor abnormality determination pulses (R1, R2) is stored. The motor start abnormality determination means (C5a, C6a) is provided for detecting the rotation speed detection pulse (R) of the set number of motor abnormality determination pulses (R1, R2) within the maximum allowable time (TM1a, TM2a). It is determined that the motor rotation is abnormal. The abnormal stop means (C2a, C4a) at the time of starting the motor
When the motor start abnormality determination means (C5a, C6a) determines that the motor rotation is abnormal, the motor (M2, M2
4) Stop. Therefore, abnormal rotation of the motor at the time of starting the motor can be promptly detected, and the rotation of the motor can be stopped immediately when the abnormal rotation of the motor is detected.

(Second Invention) A motor abnormality stop device according to a second invention is the same as the first invention, except that the following constituent requirements (A01 '),
(A04 '). (A01 ') The motor start signal which is a rotation start signal of the motor (M2) for rotating the rotating member (PR) rotating while contacting the other rotating member (B) rotated by the other motor (M4). The motor drive circuit (D2) for outputting the motor drive power to the motor (M2) in accordance with the output, (A04 ')
A motor (M2) that rotates a rotating member (PR) that rotates while contacting the other rotating member (B) when the motor start abnormality determining means (C5a) determines that the motor rotation is abnormal; Abnormal motor stop means (C2a, C4) for simultaneously stopping the motor (M4)
a).

(Operation of the Second Invention)
In the motor abnormal stop device of the invention, the motor drive circuit (D2) outputs the motor drive power to the motor (M2) in accordance with the output of the motor start signal that is a rotation start signal of the motor (M2). The motor (M2) rotates the rotating member (PR) that rotates while contacting the other rotating member (B) rotated by the other motor (M4).
The abnormal stop means (C2a, C4a) at the time of starting the motor,
A motor (M2) that rotates a rotating member (PR) that rotates while contacting the other rotating member (B) when the motor start abnormality determining means (C5a) determines that the motor rotation is abnormal; The motor (M4) is stopped at the same time. Therefore, it is possible to prevent the rotation member (PR) driven by the motor (M2) from rotating by frictional contact with the other rotation member (B) driven by the other motor (M4) for a long time. Therefore, it is possible to prevent the other rotating member (B) and the rotating member (PR) rotating while contacting the rotating member (B) from being worn due to frictional contact rotation.

(Third invention) A motor abnormality detection device according to a third invention is characterized by having the following constituent elements (A01) to (A03). (A01) A motor drive circuit (D2, D4) for outputting motor drive power to the motors (M2, M4) in response to the output of a motor start signal which is a rotation start signal of the motors (M2, M4) for rotating the rotating members. , (A02) the motor (M
2, M4), a rotation speed detection pulse generator (EN1, M2) generates a rotation speed detection pulse (R) having a frequency corresponding to the rotation speed of the motor (M2, M4).
EN2), (A03) the number of rotation speed detection pulses (R) generated by the rotation speed detection pulse generators (EN1, EN2) after a reference time T0 determined according to the output time of the motor start signal is Set pulse number (R
1, R2), the maximum allowable time (T
M1a, TM2a) and a maximum permissible time setting value storage means (C5a2, C6a2) for storing the set number of motor abnormality determination pulses (R1, R2) within the maximum permissible time (TM1a, TM2a). Motor start abnormality determination means (C5a, C6a) for determining that the motor rotation is abnormal when the detection pulse (R) is not detected.

(Operation of the third invention)
In the motor abnormality detection device according to the invention, the motor drive circuit (D
, D4) are motors (M2, M
The motor driving power is output to the motors (M2, M4) according to the output of the motor start signal which is the rotation start signal of 4). The rotation speed detection pulse generator (EN1, EN2)
When the motors (M2, M4) rotate, the motors (M
2, M4) generates a rotation speed detection pulse (R) having a frequency corresponding to the rotation speed. The maximum permissible time setting value storage means (C5a2, C6a2) stores the rotation speed detection pulses generated by the rotation speed detection pulse generators (EN1, EN2) after a reference time T0 determined according to the output time of the motor start signal. The maximum allowable time (TM1a, TM2a) required for the number of (R) to become the set number of motor abnormality determination pulses (R1, R2) is stored. The motor start abnormality determination means (C5a, C6a) is provided for detecting the rotation speed detection pulse (R) of the set number of motor abnormality determination pulses (R1, R2) within the maximum allowable time (TM1a, TM2a). It is determined that the motor rotation is abnormal. Therefore, abnormal rotation of the motor at the time of starting the motor can be promptly detected.

(Fourth Invention) A motor abnormality stop device according to a fourth invention is characterized in that it has the following components (B01) to (B04). (B01) A motor drive circuit (D2, D4) for outputting motor drive power to the motors (M2, M4) according to the output of a motor start signal which is a rotation start signal of the motors (M2, M4) for rotating the rotating members. , (B02) the motor (M
2, M4), a rotation speed detection pulse generator (EN1, M2) generates a rotation speed detection pulse (R) having a frequency corresponding to the rotation speed of the motor (M2, M4).
EN2), (B03) The rotation speed detection pulse generator (E
N1, EN2) is the maximum time required for the number of rotation speed detection pulses (R) generated during the steady rotation of the motor (M2, M4) to become the set number of motor abnormality determination pulses (R3, R4 to R5). Maximum allowable time setting value storage means (C5b2, C6b2) for storing allowable time (TMa, TMb)
Motor steady-state abnormality determining means (C5b, C6b) for determining that the motor rotation is abnormal when the set number of pulses (R3, R4 to R5) is not detected within the maximum allowable time (TMa, TMb). (B04) Motor stationary abnormal stop means (C2b, C4b) for stopping the motors (M2, M4) when the motor stationary abnormal determination means (C5b, C6b) determines that the motor rotation is abnormal.

(Operation of the Fourth Invention)
In the motor abnormal stop device of the present invention, the motor drive circuit (D
, D4) are motors (M2, M
The motor driving power is output to the motors (M2, M4) according to the output of the motor start signal which is the rotation start signal of 4). The rotation speed detection pulse generator (EN1, EN2)
When the motors (M2, M4) rotate, the motors (M
2, M4) generates a rotation speed detection pulse (R) having a frequency corresponding to the rotation speed. The maximum permissible time setting value storage means (C5b2, C6b2) stores the rotation speed detection pulse generators (EN1, EN2) in the motor (M5).
2, M4), the number of rotation speed detection pulses (R) generated during steady rotation is the set number of motor abnormality determination pulses (R3, R4).
4 to R5), the maximum allowable time (TM)
a, TMb). The motor steady-state abnormality determining means (C5b, C6b) provides the maximum allowable time (TMa, T
If the set number of pulses (R3, R4 to R5) is not detected within Mb), it is determined that the motor rotation is abnormal.
The motor stationary abnormal stop means (C2b, C4b) is configured to output the motor (M2, M4) when the motor stationary abnormality determining means (C5b, C6b) determines that the motor rotation is abnormal during the steady rotation of the motor (M2, M4). ) To stop. Therefore, the abnormal rotation of the motors (M2, M4) during the steady rotation of the motor can be promptly detected, and the rotation of the motor can be stopped immediately when the abnormal rotation of the motor is detected.

(Fifth invention) A motor abnormality stopping device according to a fifth invention is the same as the fourth invention, except that the following structural requirements (B0
1 ′) and (B04 ′). (B0
1 ') According to the output of the motor start signal which is a rotation start signal of the motor (M2) for rotating the rotating member (PR) rotating while contacting another rotating member rotated by the other motor (M4). The motor drive circuit (D2) that outputs the motor drive power to the motor (M2), (B0
4 ′) a motor (M2) that rotates a rotating member (PR) that rotates while contacting the other rotating member (B) when the motor steady-state abnormality determining means (C5b) determines that the rotation of the motor is abnormal; The motor stationary abnormal stop means (C2) for simultaneously stopping the other motor (M4)
b, C4b).

(Effect of the Fifth Invention) The fifth invention having the above configuration
In the motor abnormality stop device according to the invention, the motor drive circuit (D2) outputs the motor drive power to the motor (M2) according to the output of the motor start signal that is a rotation start signal of the motor (M2). . The motor (M2) rotates the rotating member (PR) that rotates while contacting the other rotating member (B) rotated by the other motor (M4).
The abnormal stop means (C2b, C4b) at the time of the motor steady state includes:
A motor (M2) that rotates a rotating member (PR) that rotates while contacting the other rotating member (B) when the motor steady-state abnormality determining means (C5b) determines that the motor rotation is abnormal; The motor (M4) is stopped at the same time. Therefore, it is possible to prevent the rotation member (PR) driven by the motor (M2) from rotating by frictional contact with the other rotation member (B) driven by the other motor (M4) for a long time. Therefore, it is possible to prevent the other rotating member (B) and the rotating member (PR) rotating while contacting the rotating member (B) from being worn due to frictional contact rotation.

(Sixth invention) A motor abnormality detection device according to a sixth invention is characterized by having the following constituent features (B01) to (B03). (B01) A motor drive circuit (D2, D4) for outputting motor drive power to the motors (M2, M4) according to the output of a motor start signal which is a rotation start signal of the motors (M2, M4) for rotating the rotating members. , (B02) the motor (M
2, M4), a rotation speed detection pulse generator (EN1, M2) generates a rotation speed detection pulse (R) having a frequency corresponding to the rotation speed of the motor (M2, M4).
EN2), (B03) The rotation speed detection pulse generator (E
N1, EN2) is the maximum time required for the number of rotation speed detection pulses (R) generated during the steady rotation of the motor (M2, M4) to become the set number of motor abnormality determination pulses (R3, R4 to R5). Maximum allowable time setting value storage means (C5b2, C6b2) for storing allowable time (TMa, TMb)
Motor steady-state abnormality determining means (C5b, C6b) for determining that the motor rotation is abnormal when the set number of pulses (R3, R4 to R5) is not detected within the maximum allowable time (TMa, TMb). .

(Operation of the Sixth Invention) The sixth invention having the above-described configuration
In the motor abnormality detection device according to the invention, the motor drive circuit (D
, D4) are motors (M2, M
The motor driving power is output to the motors (M2, M4) according to the output of the motor start signal which is the rotation start signal of 4). The rotation speed detection pulse generator (EN1, EN2)
When the motors (M2, M4) rotate, the motors (M
2, M4) generates a rotation speed detection pulse (R) having a frequency corresponding to the rotation speed. The maximum permissible time setting value storage means (C5b2, C6b2) stores the rotation speed detection pulse generators (EN1, EN2) in the motor (M5).
2, M4), the number of rotation speed detection pulses (R) generated during steady rotation is the set number of motor abnormality determination pulses (R3, R4).
4 to R5), the maximum allowable time (TM)
a, TMb). The motor steady-state abnormality determining means (C5b, C6b) provides the maximum allowable time (TMa, T
If the set number of pulses (R3, R4 to R5) is not detected within Mb), it is determined that the motor rotation is abnormal.
Therefore, the motor (M2, M4) during the steady rotation of the motor
Rotation abnormality can be promptly detected.

[0018]

(Embodiment 1) Embodiment 1 of the motor abnormality detecting apparatus according to the present invention is characterized in that any one of the first to third inventions has the following configuration requirement (A05). (A05) Two motor abnormality determination setting pulse numbers R1 and R1
The motor abnormality determination set pulse number storage means (C5a1, C6a1) for storing R2; and two set values TMia = TM1a, as the set value TMia of the maximum allowable time.
The maximum permissible time set value storage means (C5a2, C6a2) for storing TM2a, and the time required to detect the pulses of the set number R1 and R2 of motor abnormality determination pulses is defined as TM1 and TM2. In this case, TM1 <TM
1a and when TM2 <TM2a, the motor start abnormality determination means (C5a, C6a) that determines that the motor is normal, and otherwise determines that it is abnormal.

(Operation of the First Embodiment) In the first embodiment of the motor abnormality detecting apparatus according to the present invention having the above-described configuration, the motor abnormality determination set pulse number storage means (C5a1, C6a)
1) is R as the set pulse number for the motor abnormality determination.
The two set numbers of motor abnormality determination pulses, 1 and R2, are stored. The maximum allowable time setting value storage means (C5a2, C5a2
6a2) stores two setting values TMia = TM1a and TM2a as the setting value TMia of the maximum allowable time. Abnormality determination means at motor start (C5a, C6a)
When TM1 <TM1a and TM2 <TM2a, if TM1 <TM1a and TM2 <TM2a, it is determined that the motor is normal. Otherwise, it is determined to be abnormal.

(Embodiment 2) Embodiment 2 of the motor abnormality detecting apparatus according to the present invention has any of the first to sixth inventions or Embodiment 1 and has the following configuration requirement (A06). It is characterized by having. (A06) The maximum allowable time set value storage means (C5a) in which 1 is set as the set number of motor abnormality determination pulses (TM1a, TMa).
2, C5b2, C6a2, C6b2), the motor abnormality determining means (C5, C6).

(Operation of the Second Embodiment) In the second embodiment of the motor abnormality detecting apparatus according to the present invention having the above-described configuration, the maximum allowable time setting value storage means (C5a2) of the motor abnormality determination means (C5, C6). , C5b2, C6a2, C6b
2) is the set number of pulses for motor abnormality determination (TM1
a, TMa) is set to 1. Therefore,
Since the rotation speed of the motor can be detected by detecting one rotation speed detection pulse R, the rotation speed of the motor (M2, M4) can be detected most quickly.

(Embodiment 3) Embodiment 3 of the motor abnormality detecting apparatus of the present invention is the same as that of any of the second to sixth inventions, or Embodiment 1 or 2, except for the following constitutional requirement (A07). It is characterized by having. (A07)
The maximum allowable time (TM1a, TM2a, TMa, TM
The number of rotation speed detection pulses (R) detected in b) is a count value of the number of times of detection of either the rising edge or the falling edge of the motor abnormality determination means (C).
5, C6).

(Operation of the Third Embodiment) In the third embodiment of the motor abnormality detecting apparatus according to the present invention having the above-described configuration, the motor abnormality determining means (C5, C6) is provided with the maximum allowable time (TM1a, TM2a). , TMa, TMb) is the count value of the number of detections of either one of the rise and fall of the pulse. Therefore, the rotation speed detection pulse generator (E
Regardless of whether the first output change from the start of the operation of N1, EN2) is falling or rising, counting of the number of rotation speed detection pulses (R) can be started from the first output change. .

(Examples) Next, specific examples (examples) of embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples. (Embodiment 1) FIG. 1 is an overall explanatory view of Embodiment 1 of an image forming apparatus provided with a motor abnormality detecting device of the present invention. In FIG. 1, the image forming apparatus U includes an automatic document feeder U1 and an image forming apparatus main body (copier) U2 having a platen glass PG for supporting the same. The automatic document feeder U1 moves a document feed tray TG1 on which a plurality of documents G to be copied are stacked and a copy position (document reading position) on the platen glass PG from the document feed tray TG1. And a document discharge tray TG2 from which the document G passed and conveyed is discharged. The image forming apparatus main body U
Reference numeral 2 denotes a UI (user interface) through which a user inputs an operation command signal such as a copy start signal, and an exposure optical system A
Etc. Reflected light from a document conveyed on the platen glass PG by the automatic document feeder U1 or a document (not shown) manually placed on the platen glass PG is transmitted through the exposure optical system A to the CCD (CCD). The signals are converted into R (red), G (green), and B (blue) electric signals by a solid-state imaging device. IPS (Image Processing System)
Converts the RGB electrical signals into Y (yellow), M (magenta), C (cyan), and K (black) image data, temporarily stores the image data, and drives the image data with laser driving at a predetermined timing. Output to the circuit DL.

The surface of the image carrier (rotating member) PR which rotates in the direction of the arrow Ya is uniformly charged by the charging roll CR, and the latent image writing position Q1, the developing region Q2, and the primary transfer region Q3 are moved. Pass sequentially. The laser drive circuit DL
The ROS (latent image writing device) is driven by the laser beam L to perform exposure scanning at the latent image writing position Q1 to form an electrostatic latent image on the surface of the image carrier PR. When a full-color image is formed, electrostatic latent images corresponding to four color images of Y (yellow), M (magenta), C (cyan), and K (black) are sequentially formed.
Only the electrostatic latent image corresponding to the (black) image is formed.

The surface of the image carrier PR on which the electrostatic latent image is formed is rotated and sequentially passes through the development area Q2 and the primary transfer area Q3. The rotary-type developing device G sequentially rotates and moves to the developing area Q2 with the rotation of the rotation shaft Ga.
(Yellow), M (magenta), C (cyan), K
It has developing units GY, GM, GC, and GK for four colors (black). Each of the developing units GY, GM, GC, and GK has a developing roll DR for transporting a developer to the developing area Q2, and forms an electrostatic latent image on the image carrier PR passing through the developing area Q2. Develop into a toner image Tn.

Below the image carrier PR, a slide frame F1 is provided by a pair of left and right slide rails SR, SR.
(Indicated by a two-dot chain line) is supported so as to be slidable back and forth (in a direction perpendicular to the paper surface). Slide frame F1
Supports a belt frame F2 of the belt module BM so as to be rotatable up and down around a hinge axis F2a. The belt module BM includes a plurality of belt support rolls (Rd, Rt, Rm, Rf, T2a) that rotatably support the intermediate transfer belt (other rotating member) B, a primary transfer roll T1, and a contact. It has rolls T2c and the belt frame F2 that supports them. The plurality of belt support rolls (Rd, Rt, Rm, Rf,
T2a) includes a belt drive roll Rd, a tension roll Rt, a steering roll Rm, an idler roll (free roll) Rf, and a backup roll T2a, and the contact roll T2c is in contact with the backup roll T2a.

The belt module BM is rotatable up and down around the hinge axis F2a. When the belt module BM is rotated downward, the belt module BM does not come into frictional contact with the image carrier PR together with the slide frame F1 to form an image. Device body U
2 can go in and out. To the primary transfer device T1, a transfer voltage having a polarity opposite to the polarity of the charged toner is applied by a power supply circuit E controlled by a controller C.
The toner image Tn on the front surface is primarily transferred to the intermediate transfer belt B in the primary transfer area Q3. For full color images,
Toner images Tn of each color sequentially formed on the surface of image carrier PR
Are sequentially superimposed on the surface of the intermediate transfer belt B in the primary transfer area Q3, and a full-color multiple toner image is finally formed on the intermediate transfer belt B. When a monochromatic monocolor image is formed, only one developing unit is used, and the monochromatic toner image is primarily transferred onto the intermediate transfer belt B. After the primary transfer, the surface of the image carrier PR is cleaned of residual toner by the image carrier cleaner CLp, and is discharged by the discharging roller JR.

Below the backup roll T2a, a secondary transfer slide frame Fs slidable forward and backward (in a direction perpendicular to the paper surface) by a pair of left and right slide rails SR, SR with respect to the image forming apparatus main body U2. It is supported detachably. A secondary transfer lifting frame Ft of the secondary transfer unit Ut is supported on the secondary transfer slide frame Fs so as to be rotatable up and down around a hinge axis Fta. When the secondary transfer unit Ut is rotated downward, the secondary transfer unit Ut does not come into frictional contact with the belt module BM.
The user can enter and exit the image forming apparatus main body U2. 2 above
The secondary transfer unit Ut includes a secondary transfer roll T2b, a secondary transfer roll cleaner CLt, a roll support lever Lr,
Sheet guide SG2 after transfer and sheet transport belt BH
And the secondary transfer elevating frame Ft supporting them.
And

The roll support lever Lr is a lever that supports the secondary transfer roll T2b and the secondary transfer roll cleaner CLt. The roll support lever Lr is rotated around a hinge axis La by a motor (not shown) to rotate the secondary transfer roll T2b. The intermediate transfer belt B is moved between a secondary transfer position in contact with the intermediate transfer belt B and a standby position separated from the intermediate transfer belt B. A secondary transfer area Q4 is formed by the contact area between the secondary transfer roll T2b and the intermediate transfer belt B, and a secondary transfer unit T2 is formed by the secondary transfer roll T2b, the backup roll T2a, and the contact roll T2c. I have.

The recording sheets S stored in the paper feed tray TR1 are taken out by a pickup roll Rp at a predetermined timing, separated one by one by a separating roll Rs, and conveyed to a registration roll Rr. The cashier roll Rr
The recording sheet S conveyed to the pre-transfer sheet guide S is timed to move the primary-transferred multi-toner image or single-color toner image to the secondary transfer area Q4.
The sheet is conveyed from G1 to the secondary transfer area Q4. When the recording sheet S passes through the secondary transfer area Q4, a secondary transfer voltage having the same polarity as the toner charging polarity is applied to the contact roll T2c of the secondary transfer unit T2 from the power supply circuit E controlled by the controller C. Is done. The secondary transfer unit T2 collectively secondary-transfers the color toner image primarily transferred onto the intermediate transfer belt B onto the recording sheet S in the secondary transfer area. The residual toner is removed from the intermediate transfer belt B after the secondary transfer by the belt cleaner CLb. The above 2
The toner adhered to the surface of the secondary transfer roll T2b is collected by the secondary transfer roll cleaner CLt.

The secondary transfer roll T2b and the belt cleaner CLb are disposed so as to be able to freely contact (separate and contact) with the intermediate transfer belt B, and when a color image is formed, the final color is not determined. It is separated from the intermediate transfer belt B until the applied toner image is primarily transferred to the intermediate transfer belt B. The secondary transfer roll cleaner CLt
Performs the separation / contact movement together with the secondary transfer roll T2b. The recording sheet S on which the toner image has been secondarily transferred is conveyed to a fixing area Q5 by a post-transfer sheet guide SG2 and a sheet conveying belt BH, and includes a heating roll Fh and a pressure roll Fp when passing through the fixing area Q5. The fixing is performed by a fixing device F having a pair of fixing rolls. The recording sheet S on which the toner image has been fixed is discharged to the recording sheet discharge tray TR2. The codes Rp, Rs,
The sheet conveying device SH is configured by the elements indicated by Rr, SG1, SG2, and BH.

(Explanation of the Control Unit of the First Embodiment) FIG. 2 is an overall explanatory view of the first embodiment of the image forming apparatus U provided with the motor abnormal stop device of the present invention. It is the figure shown by the block diagram (functional block diagram). FIG.
In the above, the controller C includes an I / O (input / output interface) for inputting / outputting an external signal and adjusting input / output signal levels, and a ROM (program) for storing programs and data for performing necessary processing. Read only memory), R for temporarily storing necessary data
It comprises an AM (random access memory), a CPU (Central Processing Unit) that performs processing according to the program stored in the ROM, and a computer having a clock oscillator and the like, and executes the program stored in the ROM. By doing so, various functions can be realized.

(Signal output element connected to the controller C) The controller C receives an output signal of the next signal output element. UI: User Interface The user interface UI includes a display unit UIa, a copy start key UIb, a copy setting number input key UIc, a numeric keypad UId, and the like. To enter. EN1: Main motor rotation speed detection encoder (rotation speed detection pulse generator) The main motor rotation speed detection encoder EN1 detects the rotation speed of the main motor M2 that rotates the image carrier PR. That is, the number of pulses corresponding to the rotation speed is generated. EN2: Encoder for detecting the rotation speed of the belt drive motor (rotation speed detection pulse generator) The encoder EN2 for detecting the rotation speed of the belt drive motor detects the rotation speed of the belt drive motor M4 that rotates the intermediate transfer belt B. That is, the number of pulses corresponding to the rotation speed is generated.

(Controlled Element Connected to Controller C) The controller C outputs a control signal for the next controlled element. D1: Developing Device Support Member Rotation Drive Circuit The development device support member rotation drive circuit D1 drives the development device support member rotation drive motor M1 to rotate and stop the rotation shaft Ga of the rotary developing device G. D2: Main Motor Drive Circuit The main motor drive circuit D2 drives the main motor M2 to rotate the image carrier PR via a gear (not shown).

D3: Developing Device Driving Circuit The developing device driving circuit D3 drives the developing device driving motor M3 to drive the developing roller of the developing device and the stirring member in the developing container (stir the developer) via a gear (not shown). ) Is rotated. D4: Belt Drive Circuit The belt drive circuit D4 drives the belt drive roller Md to rotate the belt drive roll Rd and the intermediate transfer belt B via a gear (not shown) by driving the belt drive motor M4.

(Function of Controller C) Controller C
Has the following function realizing means by a program for controlling the operation of each controlled element according to the output signal of the signal output element.

C1: Developing Device Rotation Control Unit The developing device rotation control unit C1 outputs a control signal of the developing device support member rotation drive circuit D1 to control the developing devices GY, GM, GC, and GK of the developing device G to a predetermined value. At the timing of,
Rotate to the development position or standby position and stop. C2: Main motor control means The main motor control means C2 is a main motor drive circuit D
2 to output the control signal to rotate and stop the image carrier PR at a predetermined timing. The main motor control means C2 has a motor start abnormal stop means C2a and a motor stationary abnormal stop means C2b, and the motor abnormality determination means C5 or C6 described later rotates the main motor M2 or the belt drive motor M4. When an abnormality is detected, the main motor M2 is stopped. C2a: Motor start abnormal stop means Motor start abnormal stop means C2a is a motor start abnormality determine means C5 or C6 described later.
When the motor 5a or C6a determines that the rotation of the main motor M2 or the belt drive motor M4 is abnormal and outputs a motor-off signal (or a motor start abnormality signal), the main motor M2 is stopped. C2b: Abnormal motor stopping means at steady state The abnormal motor stopping means C2b is a motor steady state determining means C5 or C6 described later.
When 5b or C6b detects a rotation abnormality of the main motor M2 or the belt drive motor M4 and outputs a motor-off signal (or a motor steady-state abnormality signal), the main motor M2 is stopped.

C3: Developing Unit Drive Control Unit The developing unit drive control unit C3 outputs a control signal of the developing unit drive circuit D3 and stops at a developing position (a position facing the image carrier PR) at a predetermined timing. Developing units GY, GM,
The developing rolls of GC and GK and the stirring member in the developing container are rotated and stopped.

C4: Belt Rotation Control Means The belt rotation control means C4 outputs a control signal of the belt drive circuit D4 to rotate and stop the belt drive roll Rd and the intermediate transfer belt B at a predetermined timing.
The belt rotation control means C4 has a motor start abnormal stop means C4a and a motor steady abnormal stop means C4b.
Detects the abnormal rotation of the belt drive motor M4 or the main motor M2, stops the belt drive motor M4. C4a: Motor start abnormal stop means The motor start abnormal stop means C4a is a motor start abnormal judgment means C5 or C6 described later.
When the motor 5a or C6a determines that the rotation of the belt driving motor M2 or M4 is abnormal and outputs a motor-off signal (or a motor starting abnormal signal), the belt driving motor M4
To stop. C4b: Abnormal motor stopping means at steady state The abnormal motor stopping means C4b is a motor steady state determining means C5 or C6 described later.
When 5b or C6b detects a rotation abnormality of the main motor M2 or the belt drive motor M4 and outputs a motor-off signal (or a motor steady-state abnormality signal), the belt drive motor M4 is stopped.

C5: Motor abnormality judging means The motor abnormality judging means C5 is an abnormality judging means for the main motor M2, and has a motor starting abnormality judging means C5a and a motor steady state abnormal judging means C5b. An abnormality of the motor rotation at a regular time (during rotation at a constant speed) is determined. C5a: Motor Start Abnormality Determination Means The motor start abnormality determination means C5a detects the rotation speed detection pulse R generated by the rotation speed detection pulse generator EN1 after a reference time T0 determined according to the output time of the motor start signal. The number is the set number of pulses R1, R2 for motor abnormality determination.
Time TM1a, TM
A maximum allowable time setting value storage means C5a2 for storing the rotation speed detection pulse R when the number of the rotational speed detection pulses R becomes equal to the motor abnormality determination set pulse numbers R1 and R2 within the maximum allowable time TM1a and TM2a. Determines that the motor rotation is normal, and otherwise determines that the motor rotation is abnormal. That is, in the first embodiment, two values R1 and R2 are set as the set number of pulses Ri for motor abnormality determination, and the set number of pulses for motor abnormality determination C5a1 stores R1 = 1 and R2 = 5. I remember. The maximum allowable time setting value storage means C5a2 stores the rotational speed detection pulse number R actually detected after the reference time T0 determined in accordance with the output time of the motor start signal with the Ri (i = 1, 2,
Elapsed time TMi (TT) until R1 = 1, R2 = 5)
M1, TM2) set value TMia (TM
1a, TM2a). Then, when the motor start abnormality determination means C5a determines that TMi <TMia (T
When M1 <TM1a and TM2 <TM2a, it is determined to be normal, and when TMi> TMia (TM1> TM1a).
Or when TM2> TM2a), it is determined to be abnormal. Therefore, the program for realizing the function of the motor start abnormality determination means C5a includes a motor abnormality determination setting pulse set by the rotation speed detection pulse generator EN1 with respect to the rotation speed detection pulse generated when the motor M2 starts. A function of motor abnormality determination set pulse number storage means C5a1 for storing the numbers R1 and R2 (R1 = 1, R2 = 5);
It has a function of a maximum permissible time setting value storage means C5a2 for storing the maximum permissible time TM1a and TM2a of the time required to detect the rotation speed detection pulses of the set pulse numbers R1 (= 1) and R2 (= 5). are doing. The motor start abnormality determination means C5a outputs a motor off signal (or a motor start abnormality signal) when it is determined that the rotation is abnormal.

In the first embodiment, the "reference time T0 determined according to the output time of the motor start signal" is the output time of the motor start signal as the reference time T0. The number of the rotation speed detection pulses R is equal to the reference time T.
The counting is performed by counting the same encoder output change (either the encoder output rise or the fall) as the first encoder output change after 0 (the change in the encoder output rising or falling earlier).

C5b: Motor steady state abnormality determination means The motor steady state abnormality determination means C5b determines whether the number R of rotation speed detection pulses generated by the rotation speed detection pulse generator EN1 when the motor M2 is in steady rotation is set for motor abnormality determination. Maximum allowable time setting value storage means C for storing the maximum allowable time TMa of the time required to reach the pulse number R3 (R3 = 1)
5b2, when the number R of the rotation speed detection pulses detected within the maximum allowable time TMa becomes the set number R3 of motor abnormality determination pulses (R3 = 1), it is determined that the motor rotation is normal. Otherwise, it is determined that the motor rotation is abnormal. In other words, the motor steady state abnormality determining means C5b
Is the maximum allowable time T in the steady rotation state of the motor M2.
The number R of rotation speed detection pulses counted in Ma
Is equal to the set number of motor abnormality determination pulses R3 (R3 = 1), it is determined that the motor rotation is normal, and otherwise, the motor rotation is abnormal. Therefore, the program for realizing the function of the motor steady-state abnormality determination means C5b includes a motor abnormality determination setting which is set by the rotation speed detection pulse generator EN1 with respect to the rotation speed detection pulse generated during the steady rotation of the motor M2. The function of the motor abnormality determination set pulse number storage means C5b1 for storing the pulse number R3 (R3 = 1) and the motor abnormality determination set pulse number R in a steady state
Maximum allowable time setting value storage means C5b for storing the maximum allowable time TMa of the time required to detect a 3 = 1 pulse
It has two functions. Motor steady-state abnormality determination means C
5b outputs a motor off signal (or a motor steady state abnormal signal) when it is determined that the rotation is abnormal.

C6: Motor abnormality judging means The motor abnormality judging means C6 is an abnormality judging means for the belt drive motor M4, and has a motor starting abnormality judging means C6a and a motor steady state abnormal judging means C6b. Then, the rotation abnormality of the motor at the time of steady state (at the time of steady speed rotation) is determined. The motor start abnormality determination means C6a and the motor steady state abnormality determination means C6b are configured the same as the motor start time abnormality determination means C5a and the motor steady state abnormality determination means C5b. Therefore, the motor start abnormality determination means C6a has a motor abnormality determination set pulse number storage means C6a1 and a maximum allowable time set value storage means C6a2.
6b is a set pulse number storage means C6b1 for motor abnormality determination.
And a maximum allowable time setting value storage means C6b2.

(Operation of Embodiment 1) FIG. 3 shows the relationship between the time chart of the operation of the main motor and the belt drive motor of the image forming apparatus of the embodiment 1 having the above-mentioned configuration and the set value of the timer for abnormality determination. FIG. (Motor start abnormality determination) When the motor-on signal is output in FIG. 3, the output time becomes the reference time T0,
The timer TM is turned on to start measuring the elapsed time.
If the elapsed time TM1 up to the first (first) output change of the encoder EN1 (EN2) is shorter than the set value TM1a of the maximum allowable time of the elapsed time, it is normal.
If it is long, it is abnormal when starting the motor. If the first output change is the rising edge of the encoder pulse, the number of encoder pulses is counted at each rising edge of the encoder pulse. If the first output change is the falling edge of the encoder pulse, the rising edge of the encoder pulse is counted. By counting the number of encoder pulses for each fall, if the elapsed time TM2 until the fifth pulse output by the encoder EN1 (EN2) is counted is shorter than the set value TM2a of the maximum allowable time of the elapsed time, It is normal, but if it is long, it is abnormal when starting the motor.

In FIG. 3, when the set time TM3a required for the timer TM to start at the time T0 and enter the steady state has elapsed, the motors M2 and M4 enter the steady state. The time TMa is set in the timer TM after the steady state is reached. If the detected pulse number R until the time TMa elapses is the set pulse number R3 (R3 = 1), the motor is normal. It is always abnormal. In the first embodiment, any one of the motors M2 and M4 is stopped at the same time in the case of the motor start abnormality or the motor steady state abnormality.

(Explanation of Flowchart) FIG. 4 is a flow chart of the motor start abnormality determination processing according to the first embodiment. FIG. 5 is an explanatory diagram of a flowchart subsequent to the flowchart of FIG. 4, and is a diagram showing a motor steady-state abnormality determination process. The processing of each ST (step) in the flowcharts of FIGS. 4 and 5 is performed according to a program stored in the ROM of the controller C. This process is executed by multitasking in parallel with other various processes of the image forming apparatus. The motor start abnormality determination process shown in FIG. 4 is performed in the same manner for both the motors M2 and M4, and is started when the power of the image forming apparatus is turned on. In ST (step) 1 of FIG. 4, it is determined whether or not a motor-on signal has been output. If no (N), ST1 is repeatedly executed. If yes (Y), the process moves to ST2.

The following processing is executed in ST2. (1) The count value N of the counter for the number of continuous executions of the motor start operation is set to N = 0. (2) Turn on the timer TM. (3) The count value of the rotational speed detection pulse number R when TM is turned on is R = 0. Next, in ST3, it is determined whether or not there is an output of the encoder EN1 (EN2). This determination is based on whether or not the first output (output at the start of the operation of the encoder EN1 (EN2)) is off (no pulse output) and turned on (whether the pulse has risen). If the first output is on (pulse output state), the determination is made based on whether the output has been turned off (whether the pulse has fallen). If the first output is a pulse rise, the number of pulses is counted by counting the number of subsequent pulse rises. If the first output is a pulse fall, the number of pulses is counted by counting the number of subsequent pulse falls.

In the case of No (N) in ST3, S
Repeat T3. ST4 if yes (Y)
Move on to The following processing is executed in ST4. (1) The measured value of timer TM (the elapsed time from time T0 to the presence of encoder output) is stored in timer measured value memory TMm. (2) The rotational speed detection pulse number R when the timer TM is on is R = R + 1. In ST5, it is determined whether or not R = R1 (= 1). If yes (Y), TM1 is stored in the timer measurement memory TMm.
(The time until the pulse number R1 (= 1) is detected) is stored. In this case, the process moves to ST6. Next, in ST6, it is determined whether or not TM1 ≦ TM1a. If yes (Y), it means that the set pulse number R1 (= 1) has been detected within the set time, which means that the motor rotation is normal. In this case, the ST3
Return to If no (N) in ST6, it means that the motor rotation is abnormal, and the process proceeds to ST7.

In ST7, an off signal of the motors M2 and M4 is output. That is, the processing of the flowchart of FIG. 4 is executed simultaneously and in parallel for the main motor M2 and the belt drive motor M4. Off signals of both M2 and the belt drive motor M4 are output. For this reason, it is possible to prevent the image carrier PR rotated by the main motor M2 and the intermediate transfer belt B driven by the belt drive motor M4 from rotating due to frictional contact for a long time. The motor M2
The main motor control means C2 and the belt rotation control means C4 (see FIG. 2) which execute the processing of the flowchart (not shown) according to the output of the OFF signal of M4 stop the main motor M2 and the belt drive motor M4.

Next, in ST8, it is determined whether or not the motors M2 and M4 have stopped. This determination is made based on, for example, whether a predetermined time (time required for stopping the motors M2 and M4) has elapsed since the output of the OFF signal. No (N)
In the case of, ST8 is repeatedly executed. If yes (Y), the process moves to ST9. In the next ST9, the following processing is executed. (1) The number N of continuous executions of the motor start operation is set to N = N + 1. (2) Turn off the timer TM.

Next, in ST10, it is determined whether or not the number N of continuous executions of the motor start operation is N ≧ N0 (N0 is a set value, and N0 = 3 in the first embodiment). S for no (N)
Move to T11. Next, the following processing is executed in ST11. (1) Output an ON signal for the motors M2 and M4. The motors M2 and M4 are started by the output of the motor-on signal. (2) Turn on the timer TM. (3) The rotational speed detection pulse number R when the timer TM is on is R = 0. Next, the process returns to ST3.

In the case of YES (Y) in ST10, the number N of continuous executions of the motor start operation is N ≧ N0 = 3, and the routine goes to ST12. That is, the motor start operation was performed when N = 0, 1, and 2, which means that the motor start operation was performed three times in total. In ST12, a motor startup abnormality is displayed on the display unit UIa. Next, the process returns to ST1.

In the case of no (N) in ST5, S
Move to T13. In ST13, it is determined whether or not R = R2 (= 5). That is, it is determined whether there is a fifth output (R2 (R2 = 5) output) of the encoder EN1 (EN2). If no (N), the process returns to ST3. If yes (Y), TM2 is stored in the timer measured value memory TMm.
This means that the elapsed time from the time T0 to the output of the fifth pulse, that is, the time until the pulse number R2 (= 5) is detected, is stored. In this case, the process moves to ST14. In ST14, TM2 ≦ TM2a
(TM2a is the set value of the maximum allowable time until the output of the fifth pulse) is determined. If the answer is NO (N) in ST14 (it is determined that the motor is abnormal at the time of starting the motor), the process proceeds to ST7. In the case of YES (Y) in the above-mentioned ST14 (when the motor is normally rotating at the time of starting the motor), the process proceeds to ST21 in FIG.

In ST21 of FIG. 5, the time measured by the timer TM is TM3a (the motors M2, M4 started at time T0).
Is determined to be equal to or longer than the value set for the time required for steady rotation. If no (N), ST21 is repeatedly executed. If yes (Y), the process moves to ST22. In ST22, the count value P of the counter for detecting the number of continuous rotation abnormalities during the steady state of the motor is set to P = 0. Next, in ST23, it is determined whether or not there is an encoder pulse output. If no (N), ST23 is repeatedly executed. If yes (Y), the process moves to ST24. In ST24, TMa (set value of the upper limit value of the encoder pulse interval at the time of steady motor operation) is set in the timer TM.

Next, in ST25, the timer TM determines whether or not the time has expired. ST2 if no (N)
Move to 6. In ST26, it is determined whether or not there is an encoder pulse output (R3 (R3 = 1) th pulse output after the timer TM is set). S for no (N)
Return to T25. If yes (Y), the process moves to ST27. The following processing is executed in ST27. (1) Reset the timer TM. (2) The count value P of the counter for detecting the number of continuous rotation abnormalities during the steady state of the motor is P = 0. After ST27, the process returns to ST25. In the case of YES (Y) in ST25, the process moves to ST28. Next, the following processing is executed in ST28 (1) The timer TM is reset. (2) P (count value of the counter for detecting the number of continuous rotation abnormalities at the time of steady state of the motor) is set to P = P + 1. Next, in ST29, it is determined whether or not P ≧ P0 (P0 = 3). Here, P0 is a set value of the number of continuous rotation abnormalities at the time of the motor steady state. If no (N), the process returns to ST25. In the case of Yes (Y), it means that the rotation abnormality continuous detection during the steady state of the motor has been performed three times P = 0, 1, and 2. In this case, the process moves to ST30.

The following processing is executed in ST30. (1) An off signal for the motors M2 and M4 is output. That is, in the first embodiment, the motor stationary abnormality determination stop processing of FIG. 5 is separately performed on the motors M2 and M4.
If an abnormality occurs to both motors M2 and M
4 are simultaneously output. (2) The motor steady rotation abnormality is displayed on the display unit UIa. In the first embodiment, when the abnormality occurs, both motors M2 and M4 are stopped at the same time. For this reason, it is possible to prevent the image carrier PR rotated by the main motor M2 and the intermediate transfer belt B driven by the belt drive motor M4 from rotating due to frictional contact for a long time.

(Embodiment 2) Embodiment 2 of the present invention is different from Embodiment 1 in the method of setting the reference time T0 at the time of starting the motor and the method of determining abnormalities in the motor steady state. The other points are the same as the first embodiment. FIG. 6 is a diagram illustrating a relationship between a time chart during operation of the main motor and the belt drive motor of the image forming apparatus according to the second embodiment of the present invention and a timer setting value for abnormality determination.

(Motor Start Abnormality Judgment) When the motor ON signal is output in FIG. 6, the time when the encoder output first changes after the output time is the reference time T0, and the timer TM is turned on. Start measuring elapsed time. Elapsed time TM1 until the first (first) output change after the reference time of encoder EN1 (EN2)
However, if the elapsed time is shorter than the set value TM1a of the maximum allowable time, it is normal, but if it is longer, it is abnormal at the time of starting the motor. If the first output change is the rising edge of the encoder pulse, the number of encoder pulses is counted at each rising edge of the encoder pulse. If the first output change is the falling edge of the encoder pulse, the rising edge of the encoder pulse is counted. By counting the number of encoder pulses for each fall, the elapsed time TM2 until the fifth pulse output from the encoder EN1 (EN2) is counted is set to the maximum allowable time set value TM of the elapsed time.
If it is shorter than 2a, it is normal, but if it is longer, it is abnormal at the time of motor start.

In FIG. 6, when the set time TM3a required for the timer TM to start at the time T0 and reach a steady state has elapsed, the motor M2 (or
M4) is in a steady state. The set value of the maximum allowable time required to detect the set number of pulses R (= 4) after the steady state is reached is TMb. Therefore, the time TMb is repeatedly set in the timer TM, and the time Tb is set.
If the encoder pulse R counted within the time TMb every time Mb elapses is R = 4, it is normal, but otherwise, it is abnormal when the motor is stationary. In the second embodiment, the first embodiment is used.
Similarly, when one of the motors M2 and M4 is abnormal at the time of starting the motor or abnormal at the time of the steady state of the motor, it is stopped at the same time. Therefore, the image carrier PR rotated by the main motor M2 and the belt driving motor M
4 can prevent the intermediate transfer belt B driven by friction contact rotation for a long time. Example 2
The other configuration is the same as that of the first embodiment.

(Explanation of Flowchart of Embodiment 2) FIG.
7 is a flowchart of a motor start abnormality determination process according to the second embodiment. FIG. 8 is an explanatory diagram of a flowchart subsequent to the flowchart of FIG. 7 and is a diagram showing a motor steady-state abnormality determining process. Each ST in the flowcharts of FIGS.
The processing of (step) is performed according to a program stored in the ROM of the controller C. This process is executed by multitasking in parallel with other various processes of the image forming apparatus. The motor start abnormality determination processing shown in FIG. 7 is similarly performed for both the motors M2 and M4, and is started when the power of the image forming apparatus is turned on. FIG. 7 shows ST1
The difference from the flowchart of FIG. 4 of the first embodiment is that −1 is added. Other processes are the same as those in FIG. In ST1-1, the encoder EN1 (EN2)
If the first output (output at the start of the operation of the encoder EN1 (EN2)) is off (there is no pulse output), it is determined whether or not the output is on (whether the pulse has risen). The first output (encoder EN1 (E
N2) output at the start of operation) is on (pulse output state)
Is determined based on whether or not the pulse is turned off (whether or not the pulse falls). S for no (N)
T1-1 is repeatedly executed. In the time chart of FIG. 6, the first output change is the rising of the pulse. If the rising of this pulse is detected, the result is YES (Y) in ST1-1, and in the case of YES (Y), the process proceeds to ST2.

The following processing is executed in ST2. (1) The count value N of the counter for the number of continuous executions of the motor start operation is set to N = 0. (2) Turn on the timer TM. (3) The count value of the rotational speed detection pulse number R when TM is turned on is R = 0. Next, in ST3, it is determined whether or not there is an output of the encoder EN1 (EN2). This determination is made based on whether the first output change (output change in ST1-1) is a pulse rise or not, and whether the pulse has fallen. In the example shown in FIG. 6, the output change in ST1-1 is a pulse rise. In this case, the determination in ST3 is made based on whether or not the pulse has fallen. In the example shown in FIG. 6, the number R of rotation speed detection pulses is counted by counting the number of times of pulse fall. First output change (output change in ST1-1)
In contrast to the example shown in FIG. 6 (change at the reference time T0), when the pulse falls, the number of pulses is counted by counting the number of subsequent pulse rises. Other processes in FIG. 7 are the same as those in FIG. In the case of YES (Y) in ST14 of FIG. 7, the process proceeds to ST21 of FIG.

In ST31 of FIG. 8, the time measured by the timer TM is TM3a (the motors M2, M4 started at time T0).
Is determined to have reached the set value of the time required until steady rotation is achieved). If no (N), ST31 is repeatedly executed. If yes (Y), the process moves to ST32. S
At T32, the count value P of the counter for detecting the number of continuous rotation abnormalities during the steady state of the motor is set to P = 0. Next, in ST33, the encoder pulse count period set value TM during normal motor operation is set.
The count value R of the encoder pulse counter in b = 0
And

Next, in ST34, it is determined whether or not there is an encoder pulse output. If no (N), ST34 is repeatedly executed. If yes (Y), the process moves to ST35. In ST35, TMb (set value of the encoder pulse count period during steady-state motor) is set in the timer TM. Next, in ST36, the count value R of the encoder pulse counter in the period TMb is set to R = R + 1.
Next, in ST37, the timer TM determines whether or not the time is up. If no (N), the process moves to ST38. S
At T38, it is determined whether or not there is an encoder pulse output. If no (N), ST38 is repeatedly executed.
If the determination is yes (Y), the process proceeds to ST36. ST3
In the case of Yes (Y) in 7, the process proceeds to ST39.

In ST39, it is determined whether R = R3. Here, R is the count value of the encoder pulse counter within the set value TMb of the encoder pulse count period during the steady state of the motor, R3 is the set number of pulses for the motor abnormality determination in the steady state, and R3 = 4. If no (N), the process moves to ST40. Next, in ST40, P (the count value of the counter for the number of times of continuous detection of abnormal rotation during normal motor operation) is set to P = P + 1. Next, in ST41, P
It is determined whether or not ≧ P0 (P0 = 3). Here, P0 is a set value of the number of continuous rotation abnormalities at the time of the motor steady state. If no (N), the process moves to ST33. If yes (Y), P = 0, 1, 2
Means three times. In this case, the process moves to ST42.

The following processing is executed in ST42. (1) An off signal for the motors M2 and M4 is output. That is, the motors M2 and M4 are separately shown in FIG.
Is performed, but when an abnormality occurs in one of the motors M2 or M4, an off signal of both motors M2 and M4 is output. (2) Display a motor abnormality on the display unit UIa. In the second embodiment, as in the first embodiment, either one of the motors M
If an abnormality occurs in the motor 2 or M4, both motors M2 and M4 are stopped at the same time. For this reason, it is possible to prevent the image carrier PR rotated by the main motor M2 and the intermediate transfer belt B driven by the belt drive motor M4 from rotating due to frictional contact for a long time.
If yes (Y) in ST39, ST3
Return to 2.

(Embodiment 3) FIG. 9 is a flowchart of a motor steady-state abnormality determination process of Embodiment 3 and corresponds to FIG. 8 of Embodiment 2. The third embodiment of the present invention differs from the second embodiment in that the lower limit value R4 and the upper limit value R5 are set as the set number of motor abnormality determination pulses in the steady state and the value of the motor steady state encoder pulse count period set value TMb. different. The other points are the same as those of the second embodiment.

In FIG. 6, when the set time TM3a required for the timer TM to start at the time T0 and reach the steady state has elapsed, the motor M2 (or
M4) is in a steady state. The set value of the maximum allowable time in the third embodiment is TMb, and the set maximum allowable time T
When the rotational speed detection pulse number R detected within Mb is between the lower limit value R4 and the upper limit value R5 of the set pulse number (R4
≤R≤R5), it is determined that the motor rotation is normal during normal operation, and otherwise, it is determined that the motor rotation is abnormal.

(Explanation of Flowchart of Embodiment 3) ST
At 39, it is determined whether R4 ≦ R ≦ R5. Note that R
Is the set value T of the encoder pulse count period when the motor is stationary.
The count value of the encoder pulse counter within Mb, R4 is its lower limit set value, and R5 is its upper limit set value.
If no (N), the process moves to ST40.

(Modifications) Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above-described embodiments, but falls within the scope of the present invention described in the appended claims. Thus, various small design changes can be made. next,
The modification of this invention is illustrated. (H01) The present invention can also be applied to a belt other than the intermediate transfer belt, for example, a rotary drive motor such as a recording sheet conveying belt and a photosensitive belt. (H02) A sensor for detecting an environment such as temperature and humidity is provided.
According to the detected environment, the set values TM1a, TM2a
Can be configured to be set to different values. (H03) The rotation speed of the motor can be detected using a frequency generator instead of an encoder. (H04) Set time TM1a, TM in each of the above embodiments
The set values of 2a, TM3a, TMa, TMb and the set numbers R1, R2, R3, R4, R5 of the motor abnormality determination pulses can be changed.

[0071]

According to the present invention described above, the following effects can be obtained. (1) Abnormal rotation of the motor at the time of starting the motor or at the time of steady state can be promptly detected. (2) The time required for the two members rotating in contact with each other to rotate frictionally when the rotation of the motor is abnormal can be shortened. For this reason, it is possible to prevent wear of the contact rotating member and extend the life.

[Brief description of the drawings]

FIG. 1 is an overall explanatory diagram of Embodiment 1 of an image forming apparatus provided with a motor abnormality detecting device of the present invention.

FIG. 2 is an overall explanatory diagram of Embodiment 1 of an image forming apparatus U including a motor abnormal stop device according to the present invention, and is a block diagram (function block diagram) illustrating functions provided in a control portion thereof;
FIG.

FIG. 3 is a diagram illustrating a relationship between a time chart during operation of a main motor and a belt drive motor of the image forming apparatus according to the first embodiment having the above-described configuration and a timer setting value for abnormality determination.

FIG. 4 is a flowchart of a motor start abnormality determination process according to the first embodiment.

FIG. 5 is an explanatory diagram of a flowchart subsequent to the flowchart of FIG. 4, and is a diagram showing a motor steady-state abnormality determination process.

FIG. 6 is a diagram illustrating a relationship between a time chart during operation of a main motor and a belt drive motor of the image forming apparatus according to the second embodiment of the present invention and a timer setting value for abnormality determination.

FIG. 7 is a flowchart of a motor start abnormality determination process according to the second embodiment.

FIG. 8 is an explanatory diagram of a flowchart subsequent to the flowchart of FIG. 7, and is a diagram illustrating a motor steady-state abnormality determination process.

FIG. 9 is a flowchart of a normal motor abnormality determination process according to the third embodiment, and corresponds to FIG. 8 of the second embodiment.

[Explanation of symbols]

B: rotating member (intermediate transfer belt), C2a, C4a: abnormal stop means at motor start, C2b, C4b: abnormal stop means at motor steady state, C5a, C6a: abnormal determination means at motor start, C5a1, C6a1: motor start C5a2, C6a2: Maximum permissible time set value storage means at motor start, C5b, C6b: Motor steady-state abnormality determination means, C5b1, C6b1: Motor abnormality determination at motor steady rotation Setting pulse number storage means, C5b2, C6b2: maximum allowable time set value storage means during normal rotation of the motor, D2, D4: motor drive circuit, EN1, EN2: rotation speed detection pulse generator (rotation speed detection encoder), M2, M4: motor, PR: rotating member (image carrier), R1, R2, R3, R4 to R5: motor Number of setting pulses for abnormality determination, T0: Reference time, TMa, TMb: Maximum allowable time, TM1a, TM2a: Maximum allowable time,

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsuaki Kuroda 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Takashi Hoshino 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Shinichi Kanaya 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Naoto 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Kazuo Takano 2274 Hongo, Ebina-shi, Kanagawa Prefecture Address Fuji Xerox Co., Ltd. (72) Inventor Yukitomo Shigemori 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Tadashi Sato 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Seiichi Takayama 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Susumu Yamashina 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Norio Hokari 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. Reference) 5G044 AA07 AC01 AD01 AD04 AE01 CA07 CE08 5H550 AA14 AA20 DD01 FF01 FF03 LL07 LL53 LL56 MM05

Claims (6)

[Claims] 1. A motor abnormal stop device having the following components (A01) to (A04): (A01) The motor according to an output of a motor start signal which is a rotation start signal of a motor for rotating a rotating member. (A02) a rotation speed detection pulse generator that generates a rotation speed detection pulse which is a pulse having a frequency corresponding to the rotation speed of the motor when the motor rotates, (A03) Reference time T0 determined according to the output time of the motor start signal
Thereafter, a maximum permissible time setting value storage means for storing a maximum permissible time required for the number of rotation speed detection pulses generated by the rotation speed detection pulse generator to become the set number of motor abnormality determination pulses is provided. A motor start abnormality determining means for determining that the motor rotation is abnormal when a rotational speed detection pulse of the set number of motor abnormality determination pulses is not detected within the maximum allowable time; (A04) Abnormal motor stopping means for stopping the motor when the motor starting abnormality determining means determines that the rotation of the motor is abnormal. 2. The motor abnormal stop device according to claim 1, comprising the following components (A01 ') and (A04').
1 ') The motor drive power is output to the motor in response to the output of the motor start signal which is a rotation start signal of a motor that rotates a rotating member that rotates while contacting another rotating member that is rotated by another motor. (A04 ') a motor that rotates a rotating member that rotates while contacting the other rotating member when the motor start abnormality determining means determines that the motor rotation is abnormal; The abnormal stop means at the time of starting the motor to be stopped at the same time. 3. A motor abnormality detecting device having the following constitutional requirements (A01) to (A03): (A01) a motor abnormality detecting device which responds to an output of a motor start signal which is a rotation start signal of a motor for rotating a rotating member; A motor drive circuit for outputting motor drive power; (A02) a rotation speed detection pulse generator for generating a rotation speed detection pulse which is a pulse having a frequency corresponding to the rotation speed of the motor when the motor rotates; The maximum allowable time required for the number of rotation speed detection pulses generated by the rotation speed detection pulse generator to become equal to the set number of motor abnormality determination pulses after a reference time T0 determined according to the output time of the start signal. A maximum allowable time setting value storage means for storing the rotation speed detection pulse of the set number of motor abnormality determination pulses within the maximum allowable time. Motor startup abnormality determination means for determining the motor rotation abnormality. 4. A motor abnormal stop device having the following components (B01) to (B04): (B01) the motor according to an output of a motor start signal which is a rotation start signal of a motor for rotating a rotating member; (B02) a rotation speed detection pulse generator that generates a rotation speed detection pulse which is a pulse having a frequency corresponding to the rotation speed of the motor when the motor rotates, (B03) A maximum permissible time setting value storage unit that stores a maximum permissible time of a time required for the number of rotation speed detection pulses generated by the rotation speed detection pulse generator at the time of steady rotation of the motor to become the set number of motor abnormality determination pulses. A stationary motor abnormality determining means for determining that the rotation of the motor is abnormal when the set number of pulses is not detected within the maximum allowable time. (B04) Motor stationary abnormality stopping means for stopping the motor when the motor stationary abnormality determining means determines that the motor rotation is abnormal. 5. The motor abnormal stop device according to claim 4, further comprising the following components (B01 ′) and (B04 ′).
1 ') The motor drive power is output to the motor in response to the output of the motor start signal which is a rotation start signal of a motor that rotates a rotating member that rotates while contacting another rotating member that is rotated by another motor. (B04 ') a motor that rotates a rotating member that rotates while contacting the other rotating member when the motor steady-state abnormality determining means determines that the motor rotation is abnormal; The abnormal stop means at the time of the steady state of the motor for stopping at the same time. 6. A motor abnormality detecting device having the following constitutional requirements (B01) to (B03): (B01) a motor abnormality detecting device which responds to an output of a motor start signal which is a rotation start signal of a motor for rotating a rotating member; (B02) a rotation speed detection pulse generator that generates a rotation speed detection pulse which is a pulse having a frequency corresponding to the rotation speed of the motor when the motor rotates, and (B03) the rotation A maximum permissible time setting value storage unit for storing a maximum permissible time required for the number of rotation speed detection pulses generated by the speed detection pulse generator at the time of steady rotation of the motor to become the set number of motor abnormality determination pulses; And a motor steady-state abnormality determining unit that determines that the rotation of the motor is abnormal when the set number of pulses is not detected within the maximum allowable time.