JP2023073665A - image forming device - Google Patents

Abstract

To provide an image forming device with which it is possible to detect the abnormality of torque acting upon a motor when torque acts upon the motor that would cause a torque change to occur within the rated load.SOLUTION: A control unit calculates an average torque per unit time in a section A1. The control unit calculates an average torque per unit time in a section B1 after the voltage application of a primary transfer voltage starts. The control unit calculates an average torque per unit time in a section CX for each sheet of recording medium, every time one sheet of recording medium enters and passes through a secondary transfer unit. The control unit calculates an average torque per unit time in a section B2 after the conveyance of recording media is finished. The control unit calculates an average torque per unit time in a section A2 after the voltage application of the primary transfer power supply stops. When the difference in average torque between the sections A1 and A2, or between the sections B1 and B2, or in the section CX is greater than or equal to a threshold, the control unit outputs error information pertaining to the torque acting upon a belt drive motor.SELECTED DRAWING: Figure 9

Description

The present invention relates to an image forming apparatus using electrophotographic technology, such as a printer, copier, facsimile machine, or multi-function machine.

In order to prevent failures caused by the load torque of the motor, the image forming apparatus is designed to prevent overload torque exceeding the rated load from being applied to the motor when fluctuations in the rotation speed of the motor exceed a certain level and continue for a predetermined period of time. The motor is stopped or the user is notified of the presence of the motor. In order to do so, conventionally, a configuration has been proposed in which the rotation speed of the motor is detected based on an FG (Frequency Generator) signal output from the motor (Patent Document 1).

JP 2017-151528 A

In the device described in Patent Document 1, it is possible to detect an overload torque that causes the rotation speed of the motor to become unstable. could not be detected when a torque was applied to cause An example of a torque change within the rated load is when the belt cleaning blade that removes toner on the intermediate transfer belt is turned over. For example, if the gear shaft or bearing of the gear train that is used is scraped. If these are left as they are, they may lead to shortened service life of the intermediate transfer belt, motor failure, and the like, which is not preferable.

Therefore, even if a torque that causes a torque change within the above-mentioned rated load is applied, it should be possible to detect it as a torque abnormality. It could not be detected as a torque abnormality.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of detecting an abnormality in torque applied to a motor when a torque that causes a torque change within the rated load is applied to the motor. do.

An image forming apparatus according to an embodiment of the present invention includes a photosensitive drum that carries a toner image on its surface and rotates, an intermediate transfer member that rotatably abuts against the photosensitive drum, and the intermediate transfer member that is rotationally driven. primary transfer means capable of primarily transferring the toner image on the photosensitive drum to the intermediate transfer member by applying a primary transfer voltage; and a nip portion capable of nipping and conveying the recording material in contact with the intermediate transfer member. secondary transfer means capable of secondarily transferring the toner image on the intermediate transfer member onto a recording material by applying a secondary transfer voltage; voltage applying means for applying a voltage to the primary transfer device; and the intermediate transfer member a detecting means for detecting the torque applied to the driving portion as the image forming job is started; and based on the torque detected by the detecting means, the voltage of the voltage applying means is detected from the start of driving of the driving portion in response to the start of an image forming job. A difference between an average torque per unit time until the start of application and an average torque per unit time from the stop of voltage application by the voltage applying unit to the stop of driving of the driving unit in response to the end of the image forming job is equal to or greater than a threshold. and a control means capable of outputting error information relating to the torque applied to the drive unit when .

An image forming apparatus according to an embodiment of the present invention includes a photosensitive drum that carries a toner image on its surface and rotates, an intermediate transfer member that rotatably abuts against the photosensitive drum, and the intermediate transfer member that is rotationally driven. primary transfer means capable of primarily transferring the toner image on the photosensitive drum to the intermediate transfer member by applying a primary transfer voltage; and a nip portion capable of nipping and conveying the recording material in contact with the intermediate transfer member. secondary transfer means capable of secondarily transferring the toner image on the intermediate transfer member onto a recording material by applying a secondary transfer voltage; voltage applying means for applying a voltage to the primary transfer device; and the intermediate transfer member detecting means for detecting the torque applied to the driving section with the rotation of the voltage applying means after the driving of the driving section is started in accordance with the start of an image forming job based on the torque detected by the detecting means; Average torque per unit time from the start of voltage application until the first recording material rushes into the nip portion, and unit time from the passage of the last recording material through the nip portion to the stop of voltage application by the voltage applying means and control means capable of outputting error information regarding the torque applied to the drive unit when a difference from the average torque per hit is equal to or greater than a threshold.

An image forming apparatus according to an embodiment of the present invention includes a photosensitive drum that carries a toner image on its surface and rotates, an intermediate transfer member that rotatably abuts against the photosensitive drum, and the intermediate transfer member that is rotationally driven. primary transfer means capable of primarily transferring the toner image on the photosensitive drum to the intermediate transfer member by applying a primary transfer voltage; and a nip portion capable of nipping and conveying the recording material in contact with the intermediate transfer member. a secondary transfer means capable of secondarily transferring the toner image on the intermediate transfer member onto a recording material by applying a secondary transfer voltage; means, and based on the torque detected by the detecting means, the first recording material that is being continuously conveyed enters the nip after the driving of the driving unit is started in response to the start of the image forming job. The difference between the average torque per unit time from when the second recording material is continuously conveyed until it passes through the nip and the average torque per unit time between when the second recording material enters the nip portion and passes through is equal to or greater than a threshold value. and control means capable of outputting error information relating to the torque applied to the drive unit in some cases.

An image forming apparatus according to an embodiment of the present invention includes a photosensitive drum that carries a toner image on its surface and rotates, a driving unit that drives the photosensitive drum to rotate, and a nip that contacts the photosensitive drum to form a nip. a transfer means capable of transferring the toner image on the photosensitive drum onto a recording material by applying a transfer voltage; a voltage applying means for applying a voltage to the transfer means; average torque per unit time from the start of driving of the driving unit in response to the start of an image forming job to the start of voltage application by the voltage applying unit, based on the torque detected by the detecting unit; and the torque applied to the drive unit when a difference from an average torque per unit time from the voltage application stop of the voltage application unit to the drive stop of the drive unit in response to the end of the image forming job is equal to or greater than a threshold value. and a control means capable of outputting error information relating to the.

An image forming apparatus according to an embodiment of the present invention includes a photosensitive drum that carries a toner image on its surface and rotates, a driving unit that drives the photosensitive drum to rotate, and a nip that contacts the photosensitive drum to form a nip. a transfer means capable of transferring the toner image on the photosensitive drum onto a recording material by applying a transfer voltage; a voltage applying means for applying a voltage to the transfer means; Based on the detecting means for detecting and the torque detected by the detecting means, the first recording material from the start of voltage application by the voltage applying means after the start of driving of the driving unit in response to the start of the image forming job is detected by the nip. The difference between the average torque per unit time until the recording material rushes into the nip portion and the average torque per unit time from when the last recording material passes through the nip portion to when the voltage application by the voltage applying means is stopped is equal to or greater than a threshold value. and control means capable of outputting error information relating to the torque applied to the drive unit in some cases.

An image forming apparatus according to an embodiment of the present invention includes a photosensitive drum that carries a toner image on its surface and rotates, a driving unit that drives the photosensitive drum to rotate, and a nip that contacts the photosensitive drum to form a nip. a transfer means capable of transferring the toner image on the photosensitive drum onto a recording material by applying a transfer voltage; a voltage applying means for applying a voltage to the transfer means; and a detecting means for detecting, and based on the torque detected by the detecting means, the first recording material being continuously conveyed after the start of driving of the driving section in accordance with the start of the image forming job is detected by the nip portion. The difference between the average torque per unit time from entry to passage and the average torque per unit time from entry into the nip until passage of the second recording material being continuously conveyed is and control means capable of outputting error information relating to the torque applied to the driving unit when the torque is equal to or greater than a threshold value.

An image forming apparatus according to an embodiment of the present invention includes a photosensitive drum that carries a toner image on its surface and rotates, an intermediate transfer member that rotatably contacts the photosensitive drum, and the photosensitive drum that rotates. a driving unit, a primary transfer unit which forms a first nip portion in contact with the photosensitive drum and is capable of primarily transferring the toner image on the photosensitive drum to the intermediate transfer member by applying a primary transfer voltage, and the intermediate transfer member. a secondary transfer means capable of secondarily transferring the toner image on the intermediate transfer member to the recording material by applying a secondary transfer voltage; voltage applying means for applying a voltage to the transfer means; detecting means for detecting the torque applied to the driving portion as the photosensitive drum rotates; average torque per unit time from the start of driving of the driving unit to the start of voltage application by the voltage applying unit, and the driving of the driving unit according to the end of the image forming job after the stop of voltage application by the voltage applying unit and control means capable of outputting error information regarding the torque applied to the drive unit when a difference from the average torque per unit time until the stop is equal to or greater than a threshold.

According to the present invention, when a torque that causes a torque change within the rated load is applied to the drive section, it can be detected as an abnormality in the torque applied to the drive section.

1 is a schematic diagram showing an image forming apparatus according to an embodiment; FIG. Schematic diagram for explaining a drive unit. FIG. 3 is a block diagram for explaining a control unit; 4 is a graph showing changes over time in torque applied to a motor when a large torque change exceeding the rated load occurs. 5 is a graph showing temporal changes in the rotation speed of the motor in the case of FIG. 4; 4 is a graph showing temporal changes in torque applied to the motor when torque changes occur within the rated load; 7 is a graph showing temporal changes in the rotation speed of the motor in the case of FIG. 6; 4 is a flowchart showing torque abnormality output processing; FIG. 5 is a diagram showing temporal changes in torque for explaining torque abnormality output processing; The flowchart which shows an alerting|reporting process. 1 is a schematic diagram showing a direct transfer type image forming apparatus; FIG.

<Image forming apparatus>
The present embodiment will be described below. First, the outline of the image forming apparatus of this embodiment will be described with reference to FIGS. 1 and 2. FIG. As shown in FIG. 1, the image forming apparatus 100 has four color image forming units 600Y, 600M, 600C, and 600K, also called process cartridges, arranged to face an intermediate transfer belt 61 as an intermediate transfer member. It is a transfer type full color printer.

The image forming apparatus 100 has image forming units 600Y, 600M, 600C, and 600K that form yellow, magenta, cyan, and black toner images, respectively. The image forming apparatus 100 forms a toner image on the recording material S according to an image signal from a document reading device 41 provided above the apparatus main body 100A or an external device (not shown) such as a personal computer. Examples of the recording material S include various types of sheet materials such as plain paper, thick paper, rough paper, textured paper, coated paper, plastic film, cloth, and the like.

A conveying process of the recording material S in the image forming apparatus 100 will be described. The recording materials S are stored in one or more (here, two) cassettes 62 in a stacked manner, and supplied one by one by a supply roller 63 in accordance with image formation timing. The recording material S supplied by the supply roller 63 is conveyed to the registration roller 65 arranged in the middle of the conveying path 64 . Then, skew correction and timing correction of the recording material S are performed by the registration rollers 65, and the recording material S is sent to the secondary transfer portion T2. The secondary transfer portion T2 is formed such that the recording material S can be nipped and conveyed by a secondary transfer inner roller 66 and a secondary transfer outer roller 67 that face each other with the intermediate transfer belt 61 interposed therebetween. is a nip portion (second nip portion) where a toner image can be secondarily transferred from the intermediate transfer belt 61 onto the recording material S by applying . In this embodiment, a secondary transfer voltage is applied from a secondary transfer power supply 701 (see FIG. 2) to the secondary transfer outer roller 67 as a secondary transfer means.

A process of forming an image sent to the secondary transfer portion T2 at the same timing as the above-described process of conveying the recording material S to the secondary transfer portion T2 will be described. First, image forming units 600Y to 600K will be described. However, since the image forming units 600Y to 600K for each color are basically the same except for the color of the toner, the black image forming unit 600K will be described below as a representative example. In FIG. 1, only the image forming section 600K for black is denoted by reference numerals, and the image forming sections 600Y to 600C for other colors are not denoted by reference numerals.

The image forming section 600K mainly includes a photosensitive drum 1, a charging device 2, a developing device 3, a drum cleaning blade 5, and the like. The surface of the rotating photosensitive drum 1 is uniformly charged in advance by the charging device 2, and then an electrostatic latent image is formed by the exposure device 68 driven based on the image information signal. Next, the electrostatic latent image formed on the photosensitive drum 1 is visualized through toner development by the developing device 3 . The developing device 3 develops the electrostatic latent image with toner contained in the developer to form a toner image on the photosensitive drum 1 .

After that, a predetermined pressure and a primary transfer voltage are applied by a primary transfer roller 4 arranged to face the image forming section 600K with the intermediate transfer belt 61 interposed therebetween, and the toner image formed on the photosensitive drum 1 is transferred to the intermediate transfer belt. 61 is primarily transferred. The intermediate transfer belt 61 is rotatably in contact with the photosensitive drum 1 . A primary transfer voltage is applied from a primary transfer power source 700 (see FIG. 2) to the primary transfer roller 4 as primary transfer means, so that the toner image on the photosensitive drum 1 can be primarily transferred onto the intermediate transfer belt 61 . . The primary transfer roller 4 presses the intermediate transfer belt 61 to form a transfer portion T3Y as a first nip portion between the photosensitive drum 1Y and the intermediate transfer belt 61 . The primary transfer residual toner remaining on the photosensitive drum 1 after the primary transfer is recovered by the drum cleaning blade 5 that scrapes the surface of the photosensitive drum 1 .

In this embodiment, the image forming units 600Y to 600K have four sets of yellow (Y), magenta (M), cyan (C), and black (K). However, the number of colors is not limited to four colors, and the arrangement order of colors is not limited to this. The developing device 3 uses a two-component developer containing toner and carrier as the developer. In this case, since the toner is consumed during development, the toner can be supplied to the developing device 3 of each color from toner bottles 605Y, 605M, 605C, and 605K containing toner. The replenishment developer stored in advance in the toner bottles 605Y to 605K is replenished to each developing device 3 (Y, M, C, K) by a toner replenishing device (not shown).

The intermediate transfer belt 61 onto which the toner image is primarily transferred is an endless belt that is stretched by the tension roller 6, the inner secondary transfer roller 66, and the tension rollers 7a and 7b and moves in the direction of arrow D in the figure. . The image forming process of each color, which is processed in parallel by the above-described image forming units 600Y to 600K for each color, is sequentially superimposed on the toner image of each color primarily transferred on the intermediate transfer belt 61 upstream in the movement direction (see arrow R1). It is done at the right timing. As a result, a full-color toner image is finally formed on the intermediate transfer belt 61 and conveyed to the secondary transfer portion T2.

Secondary transfer residual toner remaining on the intermediate transfer belt 61 (on the intermediate transfer body) after passing through the secondary transfer portion T2 is removed from the intermediate transfer belt 61 by the belt cleaning blade 8 that rubs the surface of the intermediate transfer belt 61. be done. The belt cleaning blade 8 is a plate-shaped rubber blade made of a rubber member such as polyurethane rubber or urethane rubber, and is brought into contact with the intermediate transfer belt 61 in an elastically deformed state. The primary transfer rollers 4 (Y, M, C, K), the intermediate transfer belt 61, the tension roller 6, the inner secondary transfer roller 66, the tension rollers 7a and 7b, etc. are used as an intermediate transfer belt unit 800. integrally established.

By the conveying process and the image forming process described above, the timing of the recording material S and the full-color toner image is matched at the secondary transfer portion T2, and the toner image is transferred from the intermediate transfer belt 61 to the recording material S. A secondary transfer takes place. After that, the recording material S is conveyed to the fixing device 9 , and the toner image is fixed on the recording material S by applying heat and pressure in the fixing device 9 . The fixing device 9 has, for example, a fixing roller heated by a heater and a pressure roller that contacts the fixing roller to form a fixing nip portion, and applies heat and pressure to the recording material S passing through the fixing nip portion. The toner image is fixed on the recording material S at .

The recording material S that has passed through the fixing device 9 is conveyed to the discharge rollers 69, and is directly discharged onto the discharge tray 601 by the discharge rollers 69 (single-sided mode), or is conveyed to the double-sided conveying path 603 for double-sided image formation. (duplex mode). In the double-sided mode, the ejection roller 69 rotates forward to convey the recording material S until the trailing edge passes through the switching member 602 , and then the ejection roller 69 rotates in the reverse direction to switch the leading and trailing edges. transported to After that, the recording material S is sent to the conveying path 64 again by the resupply roller 604 . The subsequent transportation and the image forming process on the back side are the same as in the case described above, so the description is omitted.

As shown in FIG. 2, in the present embodiment, a secondary transfer inner roller 66 that contacts the intermediate transfer belt 61 from the inner peripheral side to form a secondary transfer outer roller 67 and a secondary transfer portion T2 serves as an intermediate transfer belt. It also serves as a belt drive roller that drives the belt 61 to rotate. That is, the secondary transfer inner roller 66 is rotated by transmission of driving force generated by a belt driving motor 801 as a driving portion via a driving transmission portion 802 such as a gear. As the secondary transfer inner roller 66 rotates, the intermediate transfer belt 61 rotates in the movement direction (see arrow R1).

The belt drive motor 801 is provided with a torque sensor 900 as detection means for detecting torque applied to the belt drive motor 801 through the drive transmission section 802 as the inner secondary transfer roller 66 is driven to rotate. Although details will be described later, in the present embodiment, when a load torque that causes a torque change within the rated load is applied to the belt drive motor 801, the load torque is applied to the belt drive motor 801 based on the detection result of the torque sensor 900. Torque anomalies can be detected. The photosensitive drums 1Y to 1K are rotationally driven by drum driving motors 810Y to 810K through drive transmission units (not shown).

<Control part>
Further, as shown in FIG. 1 , the image forming apparatus 100 includes a control section 500 . The control unit 500 will be described using FIG. 3 while referring to FIGS. 1 and 2. FIG. Various devices other than those shown in FIG. 3, such as a motor (not shown) for rotating the photosensitive drums 1Y to 1K and a secondary transfer power supply 701, are connected to the control unit 500. FIG. However, since it is not the gist of the invention here, illustration and description thereof are omitted.

A control unit 500 as a control unit controls various operations of the image forming apparatus 100 such as an image forming operation, and includes, for example, a CPU (Central Processing Unit) 501 and a memory 502 . A memory 502 includes a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and stores various programs and data for controlling the image forming apparatus 100 . The CPU 501 can execute programs such as image forming jobs stored in the memory 502 and "abnormal torque output processing" (see FIG. 8), which will be described later. Note that the memory 502 can temporarily store arithmetic processing results and the like associated with the execution of various programs.

The control unit 500 is connected to the operation unit 40, the primary transfer power source 700, the belt drive motor 801, and the torque sensor 900 via an input/output interface. The operation unit 40 has an input unit 40a and a display unit 40b. The input unit 40a includes various switches and buttons for receiving input of various data such as the start and stop of various programs such as image forming jobs by the user and the type and number of sheets of recording material S. FIG. The display unit 40b as display means displays various screens such as a menu screen for presenting various programs, an input screen for displaying various data such as the type and number of recording materials S, and a notification screen for notifying the user of operation information. A liquid crystal display, for example, can be displayed. The operation unit 40 may be a so-called touch panel, or may be an external device such as a personal computer connected to the apparatus main body 100A so as to input/output data.

The control unit 500 applies a primary transfer voltage to the primary transfer rollers 4Y to 4K by controlling a primary transfer power source 700 as voltage applying means. The control unit 500 can timely acquire the torque applied to the belt drive motor 801 detected by the torque sensor 900 . Then, the control unit 500 can calculate the average torque per unit time applied to the belt drive motor 801 based on the detection result of the torque sensor 900 . Also, the control unit 500 can count the number of times an abnormality in the torque applied to the belt drive motor 801 is detected according to the detection result of the torque sensor 900 . When the control unit 500 detects a torque abnormality, the control unit 500 stops the image forming job being executed, stops driving the belt drive motor 801, or notifies the user of the torque abnormality using the display unit 40b. inform you.

Further, when executing an image forming job, the control unit 500 controls the timing of the recording material S entering the secondary transfer portion T2 and The timing at which each recording material S passes through the secondary transfer portion T2 can be obtained.

An image forming job is a series of operations based on an image signal for forming an image on the recording material S, from the start of image formation to the completion of the image forming operation. That is, after starting a preliminary operation (so-called pre-rotation) necessary for image formation, the image forming process is performed, and then a preliminary operation (so-called post-rotation) necessary for completing image formation is completed. It is a series of actions up to Specifically, it refers to the period from pre-rotation (preparatory operation before image formation) after receiving an image signal to post-rotation (operation after image formation), and includes an image formation period and a paper interval.

Next, temporal changes in the torque applied to the belt drive motor 801 and temporal changes in the rotation speed of the belt drive motor 801 accompanying the torque change will be described with reference to FIG. 2 and FIGS. 4 to 7. FIG. FIG. 4 is a graph showing temporal changes (sec) of the torque (kgf·cm) applied to the belt drive motor 801 before and after a large torque change exceeding the rated load occurs. FIG. 5 is a graph showing temporal changes in the rotation speed (rpm) of the belt drive motor 801 when a large torque change exceeding the rated load occurs.

When an abnormality occurs in the drive transmission unit 802, the secondary transfer inner roller 66 (belt drive roller), the intermediate transfer belt 61, or the like, the torque applied to the belt drive motor 801 suddenly increases as shown in FIG. may exceed the rated load of the belt drive motor 801. In that case, as shown in FIG. 5, the rotation speed of the belt drive motor 801 is greatly reduced at the timing when the torque changes abruptly. Then, after that, the rotational speed of the belt drive motor 801 tries to return to the rotational speed before the sudden change in torque, but it is unstable and fluctuates violently due to the rebound that has greatly decreased.

Conventionally, the control unit 500 acquires the rotation speed of the belt drive motor 801 detected by a rotation sensor (not shown), and the rotation speed exceeds a preset upper limit value (Vs1) or exceeds the lower limit value (Vs2). If it fell below, it was detected that a torque abnormality had occurred. When the controller 500 detects that the belt drive motor 801 has a torque abnormality, it stops the belt drive motor 801 . As described above, conventionally, it is possible to detect that a torque abnormality has occurred if the torque change is such that the rotation speed of the belt drive motor 801 becomes clearly unstable.

Therefore, conventionally, when the torque applied to the belt drive motor 801 changes within the rated load and does not destabilize the rotational speed of the belt drive motor 801, it can be detected that the torque abnormality has occurred. I didn't. FIG. 6 is a graph showing temporal changes in torque applied to the belt drive motor 801 before and after torque changes occur within the rated load. FIG. 7 is a graph showing changes over time in the rotation speed of belt drive motor 801 when torque changes within the rated load.

As shown in FIG. 6, the torque applied to the belt drive motor 801 changes less than in the case of FIG. 4 and does not exceed the rated load. When the torque changes within such a rated load, as shown in FIG. 7, the rotation speed of the belt drive motor 801 decreases at the timing of the torque change, as in the case of FIG. After the decrease, the rotational speed of the belt drive motor 801 becomes stable unlike in FIG. 5, neither exceeding the upper limit (Vs1) nor falling below the lower limit (Vs2). Therefore, when the torque applied to the belt drive motor 801 changes within the rated load, it cannot be detected that the torque is abnormal.

One of the causes of torque variation within the above rated load is, for example, the belt cleaning blade 8 being turned up. The surface friction coefficient of the intermediate transfer belt 61 may vary during manufacturing, and may change due to usage conditions and friction with the recording material S. FIG. If the frictional force between the intermediate transfer belt 61 and the belt cleaning blade 8 becomes larger than expected, a phenomenon occurs in which the belt cleaning blade 8 is buckled and turned over. As a result, the belt cleaning blade 8 causes the intermediate transfer belt 61 to generate a greater frictional force than usual, and the torque applied to the belt driving motor 801 increases. In addition, the belt cleaning blade 8 may not be able to sufficiently remove the toner on the intermediate transfer belt 61, resulting in image defects.

If the image forming apparatus 100 is continued to be used even after the belt cleaning blade 8 is turned over, the intermediate transfer belt 61 may be damaged. In that case, the broken intermediate transfer belt 61 must be replaced, and the replacement work by a service person is troublesome and costly. Furthermore, the user cannot use the image forming apparatus 100 until it is replaced, which causes downtime of the image forming apparatus 100, which is undesirable. In addition to the case where the belt cleaning blade is turned up, examples of the torque change occurring within the above rated load include the case where the shaft portion or the bearing of the belt drive motor 801 is scraped due to use.

Therefore, in the present embodiment, when the torque of the belt drive motor 801 changes within the rated load due to the turning of the belt cleaning blade 8 or the like, it is possible to detect that the torque is abnormal. The abnormal torque output processing of this embodiment will be described below with reference to FIGS. 8 and 9 while referring to FIGS. 2 and 3. FIG. FIG. 8 is a flowchart showing torque abnormality output processing. The abnormal torque output process is executed by the control unit 500 in accordance with the input of the image forming job. FIG. 9 is a diagram showing temporal changes in torque for explaining the abnormal torque output process. It should be noted that detection of an abnormality in the torque applied to the belt drive motor 801 will be described below.

As shown in FIG. 8, the control unit 500 starts driving (turns on) the belt driving motor 801 in response to the start of the image forming job (S1). The control unit 500 starts calculating the average torque per unit time in the section A1 shown in FIG. 9 based on the torque applied to the belt drive motor 801 detected by the torque sensor 900 (S2). Then, in order to primarily transfer the toner images from the photosensitive drums 1Y to 1K to the intermediate transfer belt 61, the control unit 500 starts applying the primary transfer voltage from the primary transfer power source 700 to the primary transfer rollers 4Y to 4K (S3). ).

That is, when an image forming job is started, first, in order to rotate the intermediate transfer belt 61, the belt drive motor 801 is driven to rotate the inner secondary transfer roller 66 (belt drive roller). When the primary transfer power supply 700 applies a primary transfer voltage to the primary transfer rollers 4Y to 4K, electrostatic attraction acts between the intermediate transfer belt 61 and the photosensitive drums 1Y to 1K, and the photosensitive drums 1Y to 1K. and the intermediate transfer belt 61 increases. As a result, the torque of the belt drive motor 801 that drives the inner secondary transfer roller 66 increases (time Ta1). The control unit 500 updates the average torque per unit time (for example, 0.3 sec) in the interval A1 from the start of driving the belt drive motor 801 to the start of application of the primary transfer voltage as time elapses. calculate.

After starting to apply the primary transfer voltage, the control unit 500 starts calculating the average torque per unit time in the section B1 shown in FIG. 9 (S4). Then, the control unit 500 determines whether or not the conveyance of the recording material S has started (S5), and waits until the conveyance of the recording material S starts (No in S5). The control unit 500 calculates the average torque per unit time in the interval B1 shown in FIG. 9 from the start of the conveyance of the recording material S until the first recording material S enters the secondary transfer portion T2.

As described above, when the primary transfer voltage is applied to the primary transfer rollers 4Y-4K, the dynamic frictional force between the photosensitive drums 1Y-1K and the intermediate transfer belt 61 increases. After that, when the recording material S conveyed toward the secondary transfer portion T2 enters the secondary transfer portion T2, a torque for conveying the recording material S is applied to the inner secondary transfer roller 66 . As a result, the torque of the belt drive motor 801 that drives the inner secondary transfer roller 66 is further increased (time Tb1). After the belt drive motor 801 starts to be driven, the control unit 500 controls the unit time in the section B1 from when the primary transfer power source 700 starts applying the primary transfer voltage to when the first recording material S enters the secondary transfer portion T2. The average torque per hit (for example, 0.3 sec) is calculated while being updated over time.

Then, every time one recording material S enters and passes through the secondary transfer portion T2, the control unit 500 controls section CX (C1, C2, . . . ) shown in FIG. , the average torque per unit time is calculated (S6). That is, while the recording material S enters the secondary transfer portion T2 and passes through the secondary transfer portion T2, torque for conveying the recording material S is constantly applied to the inner secondary transfer roller 66 . Therefore, the torque of the belt drive motor 801 that drives the inner secondary transfer roller 66 is maintained in a large state (for example, from time Tb1 to Tc1). When the recording material S is continuously conveyed, the torque of the belt drive motor 801 temporarily decreases when the first recording material S passes through the secondary transfer portion T2. Subsequently, when the second recording material S rushes into the secondary transfer portion T2, the torque of the belt drive motor 801 increases again. During this period, the torque of the belt drive motor 801 is maintained large. After that, the section CX is determined according to the number of times X that the recording material S enters the secondary transfer portion T2. In this way, after the start of driving of the belt driving motor 801, the control unit 500 controls the recording material S to pass through the secondary transfer portion T2 per unit time for each sheet of continuously conveyed recording material. An average torque (for example, 0.3 sec) is calculated while being updated over time.

The control unit 500 determines whether or not the difference in average torque in the section CX is equal to or greater than a threshold value (0.3 to 0.5 kgf·cm, for example) (S7). If the average torque difference in section CX is equal to or greater than the threshold (Yes in S7), the control unit 500 outputs error information regarding the torque applied to the belt drive motor 801, and displays the error information regarding this torque as a motor torque abnormality display on the display unit. 40b (S15). Further, when the control unit 500 outputs the error information, it stops driving the belt driving motor 801 (S16) before stopping the driving of the belt driving motor 801 (see S14) in response to the end of the image forming job.

In this way, in the present embodiment, the average torque per unit time from when the first recording material S, which is continuously conveyed, enters the secondary transfer portion T2 until it passes through, error information on the torque applied to the belt driving motor 801 can be output when the difference from the average torque per unit time from when the recording material S enters the secondary transfer portion T2 to when it passes through is equal to or greater than a threshold value. be.

On the other hand, if the average torque difference in section CX is smaller than the threshold value (No in S7), the control unit 500 determines whether or not the conveyance of the recording material S has ended (S8). If the conveyance of the recording material S has not ended (No in S8), the control unit 500 returns to the process of step S6 and performs the processes of steps S6 and S7.

If the conveyance of the recording material S has ended (Yes in S8), the control unit 500 starts calculating the average torque per unit time in the section B2 shown in FIG. 9 (S9). The control unit 500 determines whether or not the difference between the average torque in the interval B1 and the average torque in the interval B2 is equal to or greater than a threshold value (0.3 to 0.5 kgf·cm, for example) (S10).

If the difference between the average torque in section B1 and the average torque in section B2 is smaller than the threshold (No in S10), the control unit 500 stops the primary transfer power supply 700 from applying the primary transfer voltage (S11). The interval B2 is from the passage of the last recording material S through the secondary transfer portion T2 to the stop of application of the primary transfer voltage by the primary transfer power supply 700 (time Tb2 to Ta2). In other words, when the last recording material S passes through the secondary transfer portion T2 and the recording material S is passing through the secondary transfer portion T2, that is, the torque of the belt drive motor 801 is lower than in the section CX. The interval in which the state is maintained is interval B2.

On the other hand, if the difference between the average torque in the interval B1 and the average torque in the interval B2 is equal to or greater than the threshold (Yes in S10), the control unit 500 outputs error information regarding the torque applied to the belt drive motor 801, and outputs error information regarding this torque. is displayed on the display unit 40b (S15). Further, when outputting the error information, the control unit 500 stops driving the belt driving motor 801 (S16) before stopping the driving of the belt driving motor 801 (see S14) in response to the end of the image forming job.

Thus, in the present embodiment, the average torque per unit time from the start of voltage application of the primary transfer power source 700 until the first recording material S rushes into the secondary transfer portion T2, and the If the difference from the average torque per unit time from the passage of T2 until the voltage application of the primary transfer power source 700 is stopped is equal to or greater than a threshold, error information regarding the torque applied to the belt driving motor 801 can be output. Note that the “first” recording material S and the “last” recording material S referred to here are the “first” and the “last” recording material S when an image is formed on one recording material S. It's called 'last'.

After stopping the voltage application of the primary transfer power supply 700 (S11), the control unit 500 starts calculating the average torque per unit time in the section A2 shown in FIG. 9 (S12). The control unit 500 determines whether or not the difference between the average torque in the section A1 and the average torque in the section A2 is equal to or greater than a threshold value (0.3 to 0.5 kgf·cm, for example) (S13).

If the difference between the average torque in the section A1 and the average torque in the section A2 is smaller than the threshold (No in S13), the control unit 500 stops (turns off) the driving of the belt driving motor 801 upon completion of the image forming job (S14). ). The interval A2 is from when the primary transfer power supply 700 stops applying the primary transfer voltage to when the belt drive motor 801 stops driving according to the end of the image forming job (after time Ta2). In other words, when the voltage application of the primary transfer power supply 700 is stopped, the dynamic frictional force between the photosensitive drums 1Y to 1K and the intermediate transfer belt 61 is reduced. A section A2 is a section in which the torque is maintained in a reduced state.

On the other hand, if the difference between the average torque in section A1 and the average torque in section A2 is equal to or greater than the threshold (Yes in S13), control unit 500 outputs error information regarding the torque applied to belt drive motor 801, and outputs error information regarding this torque. is displayed on the display unit 40b (S15). Further, when outputting the error information, the control unit 500 stops driving the belt driving motor 801 (S16) before stopping the driving of the belt driving motor 801 (see S14) in response to the end of the image forming job.

Thus, in the present embodiment, the average torque per unit time from the start of driving the belt drive motor 801 in response to the start of the image forming job to the start of voltage application of the primary transfer power source 700, and If the difference from the average torque per unit time until the belt driving motor 801 stops driving according to the end of the image forming job is equal to or greater than a threshold, error information regarding the torque applied to the belt driving motor 801 can be output.

For example, when the belt cleaning blade 8 is not turned over, the average torque Tqa1 in the section A1 and the average torque Tqa2 in the section A2 are substantially equal. This is because both the section A1 and the section A2 are in the same state in which there is no recording material S in the secondary transfer portion T2 and no voltage is applied by the primary transfer power supply 700 . Also, the average torque Tqb1 in the section B1 and the average torque Tqb2 in the section B2 are substantially equal values, and the average torque TqcX in the section CX are substantially equal values.

For example, assume that the belt cleaning blade 8 is turned over in the section B2. In that case, average torque Tqb2 in section B2 is greater than average torque Tqb1 in section B1. Therefore, as described above, the control unit 500 compares the average torque Tqb2 of the section B2 and the average torque of the section B1, and if the difference between the two is equal to or greater than the preset threshold value, the belt drive motor 801 has a torque abnormality. can detect what is happening. The same applies to sections A1, A2, and CX.

For example, when the belt cleaning blade 8 is turned over in the section A1, the average torque becomes higher than normal in both the section A1 and the section A2. Therefore, it is not possible to detect that the belt drive motor 801 has a torque abnormality based only on the difference between the two. In this case, the difference between the average torque in the section A1 of the past image forming job executed before the current image forming job and the average torque in the section A1 of the current image forming job causes the belt drive motor 801 to It may be possible to detect that a torque abnormality has occurred. The same applies to the section B1 and the section C1.

As described above, the control unit 500 may immediately stop driving the belt drive motor 801 when it detects that the belt drive motor 801 has a torque abnormality. By doing so, it becomes possible to prevent failure of the device. Furthermore, since the drive time of the belt drive motor 801 can be shortened in the state where the torque abnormality occurs, the stress applied to the drive transmission section 802 can be minimized. In this way, it is possible to prevent the life of the belt drive motor 801, the drive transmission unit 802, and the like from being shortened.

In addition, when the belt drive motor 801 has a torque abnormality, it is possible to simply display the error information about the torque on the display section 40b without stopping the drive of the belt drive motor 801. FIG. Further, when error information about torque is displayed on the display section 40b, it may be so arranged that the user is prompted to perform maintenance such as replacement of the belt cleaning blade 8 by a service person.

As described above, in the present embodiment, for example, when the belt cleaning blade 8 is turned over and a torque is applied to the belt drive motor 801 that causes a torque change within the rated load that does not destabilize the rotation speed, Output error information about torque. By stopping the driving of the belt drive motor 801 in accordance with the output of the error information regarding the torque, it is possible to prevent the belt drive motor 801 from failing or shortening its life. In addition, by notifying the user according to the output of error information regarding torque, it is possible to reduce the time required for maintenance by service personnel, thereby reducing the downtime of the image forming apparatus.

[Other embodiments]
By the way, when it is detected that the belt driving motor 801 has a torque abnormality, the user can have the belt cleaning blade 8 replaced by a service person according to the display on the display section 40b. On the other hand, since the belt drive motor 801 and the drive transmission unit 802 are more expensive than the belt cleaning blade 8, it is preferable to reduce the replacement frequency as much as possible. However, if a torque abnormality occurs in the belt drive motor 801, stress due to the torque abnormality is accumulated, and the belt drive motor 801 and the drive transmission section 802 may fail. In order to prevent this, it is possible to count the number of times an abnormality in the torque generated in the belt drive motor 801 is detected, and notify the user of replacement of the belt drive motor 801 and the drive transmission unit 802 before failure based on the counted cumulative number of times. It is preferable to

A notification process for notifying the user that the belt drive motor 801 and the drive transmission unit 802 should be replaced before failure will be described below with reference to FIGS. 2 and 3 and FIG. FIG. 10 is a flowchart showing notification processing. The notification process shown here is executed by the control unit 500 at the same time as the above-described torque abnormality detection process (see FIG. 8).

As shown in FIG. 10, the control unit 500 determines whether or not a torque abnormality is detected according to the output of error information regarding the torque applied to the belt drive motor 801 by the torque abnormality detection process (see FIG. 8). (S21). If the torque abnormality is not detected, that is, if the error information is not output (No in S21), the control section 500 returns to the process of step S21. If torque abnormality is detected, that is, if error information is output (Yes in S21), the control unit 500 counts the number of detections and stores it in the memory 502 (S22).

Then, the control unit 500 determines whether or not the counted number of times of detection has exceeded a predetermined number of times (S23). If the counted number of detections does not exceed the predetermined number (No in S23), the control section 500 returns to the process of step S21. On the other hand, if the counted number of detections exceeds the predetermined number (Yes in S23), the control section 500 displays on the display section 40b a prompt for the user to replace the belt drive motor 801 and the drive transmission section 802 (S24). .

In this way, based on the output of the error information regarding the torque applied to the belt drive motor 801, the number of times the torque abnormality is detected is counted. encourage exchange. As a result, the frequency of replacement of the belt drive motor 801 and the drive transmission unit 802 can be reduced as much as possible so that they can be replaced before they fail, thereby reducing the downtime of the image forming apparatus.

In the above-described embodiment, the image forming apparatus 100 is an intermediate transfer type image forming apparatus, but the image forming apparatus 100 is not limited to this. The above-described embodiments can also be applied to a direct transfer type image forming apparatus in which toner images are directly transferred from the photosensitive drums 1Y to 1K onto a recording material conveyed by a conveying belt. A description will be given below with reference to FIG. 11 . FIG. 11 is a schematic diagram showing a direct transfer type image forming apparatus.

The image forming apparatus shown in FIG. 11 is a direct transfer type full-color printer in which the image forming units PY, PM, PC, and PK are arranged along the conveying belt 24 . In the image forming station PY, a yellow toner image is formed on the photosensitive drum 1Y and transferred onto the recording material S conveyed by the conveying belt 24 . In the image forming station PM, a magenta toner image is formed on the photosensitive drum 1M and transferred onto the recording material S conveyed by the conveying belt 24 . In the image forming units PC and PK, a cyan toner image and a black toner image are formed on the photosensitive drums 1C and 1K, respectively, and transferred onto the recording material S conveyed by the conveying belt 24 . The recording material S to which the toner image has been transferred is curvedly separated from the conveying belt 24 and sent to the fixing device 9 . The toner image is fixed on the recording material S by applying heat and pressure in the fixing device 9 .

The image forming units PY, PM, PC, and PK have the same configuration except that the toner colors used in the developing devices 3Y, 3M, 3C, and 3K are yellow, magenta, cyan, and black. Therefore, the image forming unit PY will be described below as a representative.

In the image forming section PY, a primary charger 21Y, an exposure device 68Y, a developing device 3Y, a transfer charger 45Y, and a drum cleaning blade 5Y are arranged surrounding the photosensitive drum 1Y. The photosensitive drum 1Y is rotationally driven by a drum driving motor 810Y as a driving section. The drum drive motor 810Y is provided with a torque sensor 900Y as detection means for detecting torque applied to the drum drive motor 810Y.

The primary charger 21Y charges the photosensitive drum 1Y by emitting charged particles associated with corona discharge, for example. The exposure device 68Y forms an electrostatic latent image on the surface of the charged photosensitive drum 1Y. The developing device 3Y develops the electrostatic latent image on the photosensitive drum 1Y into a toner image. A transfer charger 45Y as a transfer means has a transfer blade, and presses the transfer blade against the transport belt 24 to form a transfer portion T3Y as a nip portion between the photosensitive drum 1Y and the transport belt 24Y. A transfer voltage is applied to the transfer blade from a transfer power source 700Y as voltage applying means, whereby the toner image carried on the photosensitive drum 1Y is transferred onto the recording material S on the conveying belt 24Y. The transfer residual toner remaining on the photosensitive drum 1Y (photosensitive drum) after transfer is removed by the drum cleaning blade 5Y.

The above-described torque abnormality detection process (see FIG. 8) can also be applied to such a direct transfer type image forming apparatus. However, in the case of a direct transfer type image forming apparatus, the control unit 500 outputs error information regarding the torque applied to each of the drum drive motors 810Y to 810K, and displays the error information regarding this torque on the display unit 40b as a motor torque abnormality display. (S15 in FIG. 8). In this case, if the difference in the average torques of the sections A1 and A2, the difference in the average torques in the sections B1 and B2, and the difference in the average torques in the section CX are equal to or greater than preset threshold values, the drum drive motors 810Y to 810Y Detects that a torque abnormality has occurred at 810K.

Also in the above-described intermediate transfer type image forming apparatus, as in the above-described direct transfer type image forming apparatus, the torque abnormality of the drum drive motors 810Y to 810K (see FIG. 2) for driving the photosensitive drums 1Y to 1K can be detected. In that case, although not shown in FIG. 2, the drum drive motors 810Y to 810K are provided with torque sensors 900Y to 900K (see FIG. 11) for detecting torque applied to the drum drive motors 810Y to 810K, respectively.

In the above-described embodiment, the control unit 500 and the torque sensor 900 are provided separately, and the control unit 500 acquires the torque applied to the belt drive motor 801 detected by the torque sensor 900. (See FIG. 3), but not limited to this. For example, the control unit 500 may consider the voltage itself supplied to the belt drive motor 801 to drive the belt drive motor 801 at a constant rotational speed as data corresponding to the torque applied to the belt drive motor 801. . That is, when the torque applied to the belt drive motor 801 increases, the rotational speed of the belt drive motor 801 (specifically, the FG (Frequency Generator) signal output from the motor) decreases. In this case, the control unit 500 controls to increase the voltage supplied to the belt drive motor 801 in order to keep the rotation speed constant (target speed). As described above, the voltage supplied to the belt drive motor 801 changes according to the magnitude of the torque applied to the belt drive motor 801. It can be processed as data corresponding to torque. In other words, the controller 500 functions as a torque sensor that detects torque applied to the belt drive motor 801 .

1Y (1M, 1C, 1K)...photosensitive drum, 4Y (4M, 4C, 4K)...primary transfer means (primary transfer roller), 5...drum cleaning blade, 8...belt cleaning blade, 40b...display means (display section) , 45Y (45M, 45C, 45K) Transfer means (transfer charger) 61 Intermediate transfer member (intermediate transfer belt) 67 Secondary transfer means (outer secondary transfer roller) 100 Image forming apparatus 500 Control means (control section) 700 (700Y, 700M, 700C, 700K) Voltage application means (primary transfer power supply) 801 Driving section (belt driving motor) 810Y (810M, 810C, 810K) Driving section ( drum drive motor), 900 (900Y, 900M, 900C, 900K)... detecting means (torque sensor), T3Y (T3M, T3C, T3K)... nip portion (first nip portion, transfer portion), T2... nip portion (second second nip portion, secondary transfer portion), S: recording material

Claims (22)

a photosensitive drum that carries a toner image on its surface and rotates;
an intermediate transfer member rotatably contacting the photosensitive drum;
a driving unit that rotationally drives the intermediate transfer member;
primary transfer means capable of primarily transferring the toner image on the photosensitive drum to the intermediate transfer member by applying a primary transfer voltage;
a secondary transfer means that forms a nip portion that is in contact with the intermediate transfer body and can hold and convey a recording material, and that can secondarily transfer the toner image of the intermediate transfer body to the recording material by applying a secondary transfer voltage;
a voltage applying means for applying a voltage to the primary transfer means;
a detection means for detecting torque applied to the drive unit as the intermediate transfer member rotates;
Based on the torque detected by the detection means, the average torque per unit time from the start of driving of the driving unit in response to the start of the image forming job to the start of voltage application by the voltage application means, and the average torque of the voltage application means Error information about the torque applied to the driving unit can be output when a difference from the average torque per unit time from when the voltage application is stopped to when the driving unit stops driving according to the end of the image forming job is equal to or greater than a threshold. a control means,
An image forming apparatus characterized by: The control means controls the average torque per unit time from the start of voltage application by the voltage applying means until the first recording material enters the nip portion after the start of driving of the driving portion, when the difference from the average torque per unit time from passing through the part until the voltage application of the voltage applying means is stopped is a threshold value or more, error information regarding the torque applied to the driving part can be output.
2. The image forming apparatus according to claim 1, wherein: The control means controls an average torque per unit time from when the first recording material, which is continuously conveyed, enters the nip portion until it passes through the nip portion after the start of driving of the driving portion, and is equal to or greater than a threshold, the error information regarding the torque applied to the drive unit can be output when the difference from the average torque per unit time from when the second recording material enters the nip portion to when it passes through the nip portion is equal to or greater than a threshold value. ,
3. The image forming apparatus according to claim 1, wherein: a photosensitive drum that carries a toner image on its surface and rotates;
an intermediate transfer member rotatably contacting the photosensitive drum;
a driving unit that rotationally drives the intermediate transfer member;
primary transfer means capable of primarily transferring the toner image on the photosensitive drum to the intermediate transfer member by applying a primary transfer voltage;
a secondary transfer means that forms a nip portion that is in contact with the intermediate transfer body and can hold and convey a recording material, and that can secondarily transfer the toner image of the intermediate transfer body to the recording material by applying a secondary transfer voltage;
a voltage applying means for applying a voltage to the primary transfer means;
a detection means for detecting torque applied to the drive unit as the intermediate transfer member rotates;
Based on the torque detected by the detection means, after the start of driving of the drive unit in response to the start of the image forming job, the time from the start of voltage application by the voltage application unit until the first recording material rushes into the nip portion. When the difference between the average torque per unit time and the average torque per unit time from when the last recording material passes through the nip portion to when the voltage application by the voltage applying means is stopped is equal to or greater than a threshold value, the driving is performed. and a control means capable of outputting error information about the torque applied to the part,
An image forming apparatus characterized by: The control means controls an average torque per unit time from when the first recording material, which is continuously conveyed, enters the nip portion until it passes through the nip portion after the start of driving of the driving portion, and is equal to or greater than a threshold, the error information regarding the torque applied to the drive unit can be output when the difference from the average torque per unit time from when the second recording material enters the nip portion to when it passes through the nip portion is equal to or greater than a threshold value. ,
5. The image forming apparatus according to claim 4, wherein: a photosensitive drum that carries a toner image on its surface and rotates;
an intermediate transfer member rotatably contacting the photosensitive drum;
a driving unit that rotationally drives the intermediate transfer member;
primary transfer means capable of primarily transferring the toner image on the photosensitive drum to the intermediate transfer member by applying a primary transfer voltage;
a secondary transfer means that forms a nip portion that is in contact with the intermediate transfer body and can hold and convey a recording material, and that can secondarily transfer the toner image of the intermediate transfer body to the recording material by applying a secondary transfer voltage;
a detection means for detecting torque applied to the drive unit as the intermediate transfer member rotates;
Based on the torque detected by the detecting means, after the drive unit starts driving in response to the start of the image forming job, the first recording material being continuously conveyed enters and passes through the nip portion. when the difference between the average torque per unit time up to and the average torque per unit time from when the second recording material that is continuously conveyed enters the nip until it passes is equal to or greater than the threshold , and a control means capable of outputting error information regarding the torque applied to the drive unit,
An image forming apparatus characterized by: comprising display means,
the control means displays the error information on the display means;
7. The image forming apparatus according to claim 1, wherein: The control means counts the number of times the error information is output, and displays the error information on the display means when the counted number exceeds a predetermined number of times.
8. The image forming apparatus according to claim 7, wherein: When outputting the error information, the control means stops the drive unit before stopping the drive unit in response to the completion of the image forming job.
8. The image forming apparatus according to claim 1, wherein: a belt cleaning blade that contacts the intermediate transfer body to remove toner on the intermediate transfer body;
10. The image forming apparatus according to claim 1, wherein: a photosensitive drum that carries a toner image on its surface and rotates;
a driving unit that rotationally drives the photosensitive drum;
a transfer means that forms a nip portion in contact with the photosensitive drum and can transfer the toner image on the photosensitive drum to a recording material by applying a transfer voltage;
voltage application means for applying a voltage to the transfer means;
a detecting means for detecting torque applied to the driving portion as the photosensitive drum rotates;
Based on the torque detected by the detection means, the average torque per unit time from the start of driving of the driving unit in response to the start of the image forming job to the start of voltage application by the voltage application means, and the average torque of the voltage application means Error information about the torque applied to the driving unit can be output when a difference from the average torque per unit time from when the voltage application is stopped to when the driving unit stops driving according to the end of the image forming job is equal to or greater than a threshold. a control means,
An image forming apparatus characterized by: The control means controls the average torque per unit time from the start of voltage application by the voltage applying means until the first recording material enters the nip portion after the start of driving of the driving portion, when the difference from the average torque per unit time from passing through the part until the voltage application of the voltage applying means is stopped is a threshold value or more, error information regarding the torque applied to the driving part can be output.
12. The image forming apparatus according to claim 11, wherein: The control means controls an average torque per unit time from when the first recording material, which is continuously conveyed, enters the nip portion until it passes through the nip portion after the start of driving of the driving portion, and is equal to or greater than a threshold, the error information regarding the torque applied to the drive unit can be output when the difference from the average torque per unit time from when the second recording material enters the nip portion to when it passes through the nip portion is equal to or greater than a threshold value. ,
13. The image forming apparatus according to claim 11, wherein: a photosensitive drum that carries a toner image on its surface and rotates;
a driving unit that rotationally drives the photosensitive drum;
a transfer means that forms a nip portion in contact with the photosensitive drum and can transfer the toner image on the photosensitive drum to a recording material by applying a transfer voltage;
voltage application means for applying a voltage to the transfer means;
a detecting means for detecting torque applied to the driving portion as the photosensitive drum rotates;
Based on the torque detected by the detection means, after the start of driving of the drive unit in response to the start of the image forming job, the time from the start of voltage application by the voltage application unit until the first recording material rushes into the nip portion. When the difference between the average torque per unit time and the average torque per unit time from when the last recording material passes through the nip portion to when the voltage application by the voltage applying means is stopped is equal to or greater than a threshold value, the driving is performed. and a control means capable of outputting error information about the torque applied to the part,
An image forming apparatus characterized by: The control means controls an average torque per unit time from when the first recording material, which is continuously conveyed, enters the nip portion until it passes through the nip portion after the start of driving of the driving portion, and is equal to or greater than a threshold, the error information regarding the torque applied to the drive unit can be output when the difference from the average torque per unit time from when the second recording material enters the nip portion to when it passes through the nip portion is equal to or greater than a threshold value. ,
15. The image forming apparatus according to claim 14, characterized by: a photosensitive drum that carries a toner image on its surface and rotates;
a driving unit that rotationally drives the photosensitive drum;
a transfer means that forms a nip portion in contact with the photosensitive drum and can transfer the toner image on the photosensitive drum to a recording material by applying a transfer voltage;
voltage application means for applying a voltage to the transfer means;
a detecting means for detecting torque applied to the driving portion as the photosensitive drum rotates;
Based on the torque detected by the detecting means, after the drive unit starts driving in response to the start of the image forming job, the first recording material being continuously conveyed enters and passes through the nip portion. when the difference between the average torque per unit time up to and the average torque per unit time from when the second recording material that is continuously conveyed enters the nip until it passes is equal to or greater than the threshold , and a control means capable of outputting error information regarding the torque applied to the drive unit,
An image forming apparatus characterized by: comprising display means,
the control means displays the error information on the display means;
17. The image forming apparatus according to any one of claims 11 to 16, characterized by: The control means counts the number of times the error information is output, and displays the error information on the display means when the counted number exceeds a predetermined number of times.
18. The image forming apparatus according to claim 17, characterized by: When outputting the error information, the control means stops the drive unit before stopping the drive unit in response to the completion of the image forming job.
18. The image forming apparatus according to any one of claims 11 to 17, characterized by: a drum cleaning blade that contacts the photosensitive drum to remove toner on the photosensitive drum;
20. The image forming apparatus according to any one of claims 12 to 19, characterized by: a photosensitive drum that carries a toner image on its surface and rotates;
an intermediate transfer member rotatably contacting the photosensitive drum;
a driving unit that rotationally drives the photosensitive drum;
a primary transfer means that forms a first nip portion in contact with the photosensitive drum and can primarily transfer the toner image on the photosensitive drum to the intermediate transfer member by applying a primary transfer voltage;
secondary transfer means for forming a second nip portion capable of nipping and conveying a recording material in contact with the intermediate transfer body, and capable of secondarily transferring the toner image of the intermediate transfer body onto the recording material by applying a secondary transfer voltage; and,
a voltage applying means for applying a voltage to the primary transfer means;
a detecting means for detecting torque applied to the driving portion as the photosensitive drum rotates;
Based on the torque detected by the detection means, the average torque per unit time from the start of driving of the driving unit in response to the start of the image forming job to the start of voltage application by the voltage application means, and the average torque of the voltage application means Error information about the torque applied to the driving unit can be output when a difference from the average torque per unit time from when the voltage application is stopped to when the driving unit stops driving according to the end of the image forming job is equal to or greater than a threshold. a control means,
An image forming apparatus characterized by: The control means controls the average torque per unit time from the start of voltage application by the voltage applying means until the first recording material enters the second nip portion after the start of driving of the driving section, and When the difference from the average torque per unit time from passing through the second nip portion until the voltage application of the voltage applying means is stopped is equal to or greater than a threshold, error information regarding the torque applied to the driving portion can be output. be,
22. The image forming apparatus according to claim 21, characterized by:

Images