JP5880061B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Conventionally, electrophotographic image forming apparatuses are known as printers, copiers, and the like. In this image forming apparatus, when a deviation occurs in the conveyed paper, that is, when the paper is deviated from a predetermined position in a direction (paper width direction) orthogonal to the paper conveyance direction, the image is formed on the paper. There is an inconvenience that the printed image is displaced from the original proper position, leading to a decrease in print quality. Therefore, the image forming apparatus includes a paper correction unit that corrects the paper transport position by moving along the paper width direction. For example, the paper correction unit is driven by an electric motor.

  For example, Patent Document 1 discloses an image including a skew feeding roller that moves a sheet to the reference guide side, and a sheet correction unit (for example, a registration roller) that is provided on the downstream side of the skew feeding roller and is movable in the sheet width direction. A forming apparatus is disclosed. In this image forming apparatus, the skew is fed by a sheet to a reference guide to correct the skew, and then the sheet is nipped by a registration roller, and the registration roller is moved in the sheet width direction.

JP 2010-260696 A

  Incidentally, since the paper correction unit may operate in a state different from the normal operation state, in such a case, there is a disadvantage that the consistency between the paper position and the toner image position is lowered. is there.

  The present invention has been made in view of such circumstances, and an object thereof is to perform control so as to ensure consistency between the position of the paper P and the position of the toner image.

  In order to solve this problem, the present invention provides an image forming apparatus that forms an image on a sheet conveyed along a conveyance path. This image forming apparatus is configured to be swingable in a paper width direction, which is a direction perpendicular to the paper conveyance direction, starting from a preset home position, and corrects the conveyance position of the paper in the paper width direction. A correction unit, an electric motor that moves the sheet correction unit along the sheet width direction by being driven to rotate in accordance with the pulse signal, a sheet detection unit that detects a conveyance position of the sheet in the sheet width direction, and a sheet correction unit A position detection unit that detects whether or not the position is a home position, and a command pulse number is calculated based on the conveyance position in the sheet width direction of the sheet detected by the sheet detection unit, and the command pulse number is In addition to outputting the pulse signal to the motor and outputting the pulse signal corresponding to the number of command pulses, the paper correction unit moves to the home position based on the detection result of the position detection unit. It has a swing control section which outputs a pulse signal to the motor, and a measuring unit for measuring the number of pulses of the pulse signal outputted to the motor until the sheet correction unit is moved to the home position to be. In this case, the oscillation control unit compares the command pulse number with the pulse number measured by the measurement unit, and adjusts the output torque of the motor or the output pulse of the pulse signal.

  Here, in the present invention, when the command pulse number is larger than the pulse number measured by the measurement unit, the oscillation control unit increases the output torque of the motor or increases the command pulse number from the calculated value. It is desirable to correct the value.

  In the present invention, the oscillation control unit increases the output torque of the motor when the number of pulses measured by the measurement unit is larger than the command pulse number, or a value obtained by reducing the command pulse number from the calculated value. It is preferable to correct it.

Further, in the present invention, the swing control unit, if the predetermined specific type of paper, output torque of the electric motor, or have the line adjustment of the output pulse of the pulse signals, other than the specific type which is set in advance In the case of paper, it is preferable not to adjust the output torque of the electric motor or the output pulse of the pulse signal .

Further, in the present invention, the moving range of the paper correction unit, a first range of command pulse count and the number of pulses measured by the measuring unit are different, the number of command pulses and the number of pulses measured by the measuring unit There are two ranges of the second range that coincide with each other , and the swing control unit restricts the movement of the paper correction unit to the first range, or the paper correction unit moves to the first range. It is desirable to adjust the output torque of the electric motor or adjust the output pulse of the pulse signal only in the above case.

  According to the present invention, control can be performed so as to ensure consistency between the position of the paper and the position of the toner image.

Configuration diagram schematically showing an image forming apparatus Explanatory drawing showing the main parts of the transport path centering on the registration rollers Explanatory drawing showing the swinging state of the registration roller Block diagram showing control system of image forming apparatus The flowchart which shows the control procedure of the rocking | fluctuation motor concerning 1st Embodiment. The flowchart which shows the control procedure of the rocking | fluctuation motor concerning 3rd Embodiment.

  FIG. 1 is a configuration diagram schematically illustrating an image forming apparatus according to the present embodiment. This image forming apparatus is an electrophotographic image forming apparatus such as a copying machine, and forms a full-color image by arranging a plurality of photoconductors facing one intermediate transfer belt in a vertical direction. A tandem type color image forming apparatus.

  The image forming apparatus mainly includes a document reading device SC, an image forming unit 10, and a fixing device 50, which are housed in a single casing.

  The document reader SC scans and exposes an image of the document with the optical system of the scanning exposure device, reads the reflected light with a line image sensor, and obtains an image signal. The image signal is subjected to processing such as A / D conversion, shading correction, and compression, and then input to the control unit 40 as image data. Note that the image data input to the control unit 40 is not limited to data read by the document reading device SC, but is, for example, data received from a personal computer connected to the image forming device or another image forming device. Also good.

  The image forming unit 10 has a function of transferring a toner image onto the paper P, and is mainly composed of four sets of image forming units 10Y, 10M, 10C, and 10K. The image forming units 10Y to 10K include an image forming unit 10Y that forms a yellow (Y) image, an image forming unit 10M that forms a magenta (M) image, and an image forming unit that forms a cyan (C) image. 10C is an image forming unit 10K that forms a black (K) image.

  The image forming unit 10Y includes a photosensitive drum 1Y and a charging unit 2Y, an optical writing unit 3Y, a developing device 4Y, and a drum cleaner 5Y arranged around the photosensitive drum 1Y. Similarly, the image forming units 10M, 10C, and 10K include the photosensitive drums 1M, 1C, and 1K and charging units 2M, 2C, and 2K, optical writing units 3M, 3C, and 3K, and developing devices 4M, arranged around the photosensitive drums 1M, 1C, and 1K. 4C, 4K and drum cleaners 5M, 5C, 5K.

  The surfaces of the photosensitive drums 1Y to 1K are uniformly charged by the charging units 2Y to 2K, and latent images are formed on the photosensitive drums 1Y to 1K by scanning exposure by the optical writing unit 3Y. . Further, the developing devices 4Y to 4K develop latent images on the photosensitive drums 1Y to 1K by developing with toner. As a result, toner images corresponding to yellow, magenta, cyan, and black are formed on the respective photosensitive drums 1Y to 1K. The toner images formed on the photosensitive drums 1Y to 1K are sequentially transferred to predetermined positions on the rotating intermediate transfer belt 6 by primary transfer rollers 7Y, 7M, 7C, and 7K.

  The toner image composed of each color transferred onto the intermediate transfer belt 6 is transferred onto the paper P conveyed at a predetermined timing by the transfer roller 9.

  The paper transport unit 20 transports the paper P along the transport path. The paper P is accommodated in the paper feed tray 21, and the paper P accommodated in the paper feed tray 21 is taken in by the paper feed unit 22 and is sent out to the transport path. In this transport path, a plurality of intermediate transport rollers, loop rollers 23, and an upstream side of an image forming position for forming an image on the paper P (specifically, an image transfer position for transferring a toner image onto the paper P) A plurality of conveying members including the registration roller 24 are arranged. Each conveyance member is constituted by a pair of conveyance rollers, for example, and the state between the rollers can be switched between a nip state and a nip release state as necessary.

  FIG. 2 is an explanatory diagram showing the main part of the conveyance path of the paper P around the registration roller 24. Specifically, the paper P fed from the paper feed tray 21 passes through a plurality of intermediate transport rollers, is then transported by the loop roller 23, and hits the registration roller 24 in a rotation stopped state. As the loop roller 23 continues to rotate for a predetermined time, a loop is formed on the paper P, whereby the bending of the paper P is corrected (skew correction). Next, when the registration roller 24 starts to rotate at a predetermined timing and resumes the conveyance of the paper P, the registration roller 24 performs a swinging operation to be described later while conveying the paper P, and conveys it to the image transfer position.

  FIG. 3 is an explanatory view showing the swinging state of the registration roller 24. The registration roller 24 is configured to be swingable in a paper width direction CD (a direction perpendicular to the paper transport direction FD on the paper surface of the paper P) starting from a preset home position. An output shaft of a swing motor 25 is connected to the registration roller 24 via a power transmission mechanism (not shown). The registration roller 24 is moved along the paper width direction CD in accordance with the rotational drive of the swing motor 25. Move. For this reason, the registration roller 24 moves from the home position to the predetermined position along the paper width direction CD in accordance with the passage period during which the paper P passes the registration roller 24, whereby the conveyed paper P is moved along the paper width direction CD. Can be moved. Accordingly, the registration roller 24 can correct the transport position of the paper P in the paper width direction CD (paper correction unit).

  In the present specification, of the movement operations of the registration roller 24, the movement from the home position to a predetermined position (a position determined according to the transport position of the paper P) is referred to as an initial operation, and the predetermined position after the initial operation. The movement from the home position to the home position is called a return movement.

  The swing motor 25 is an electric motor that is driven to rotate in response to a pulse signal, and is, for example, a stepping motor. When a predetermined pulse signal is input to the oscillating motor 25, a pulsed voltage is applied to the winding of the oscillating motor 25, whereby a rotation angle corresponding to the number of pulses included in the pulse signal, and The output shaft of the oscillating motor 25 rotates at a rotation speed corresponding to the pulse period. The registration roller 24 moves by a predetermined amount in accordance with the number of pulses included in the pulse signal input to the swing motor 25, whereby the paper P can be moved by a predetermined amount.

  Referring again to FIG. 1, the paper P on which the toner image is transferred is conveyed to the fixing device 50. The fixing device 50 is a device that fixes an unfixed toner image on the paper P. For example, the fixing device 50 heats a pair of fixing members (for example, a fixing roller) forming a fixing nip portion and one or both of the fixing members. It consists of a heater and a. In the fixing device 50, the sheet P passes through the fixing nip portion in the process of transporting the sheet P, so that the toner image is applied to the sheet P through the action of the pressure by the pair of fixing members and the heat of the fixing member. Fix it.

  The paper P subjected to the fixing process by the fixing device 50 is discharged by a paper discharge roller to a paper discharge tray 26 attached to the outer side surface of the housing. When image formation is performed also on the back surface of the paper P, the paper P on which image formation on the front surface of the paper has been completed is conveyed by the guide member 30 to the reverse roller 31 below. The reversing roller 31 pinches the rear end of the conveyed paper P, reverses the paper P by reverse feeding, and sends it out to the refeed conveyance path. The sheet P sent out to the refeed conveyance path is conveyed by a plurality of conveyance members including the intermediate conveyance roller and the pre-registration roller 32, and thereby returns to the conveyance path upstream of the loop roller 23. .

  FIG. 4 is a block diagram schematically showing a control system of the image forming apparatus according to the present embodiment. The control unit 40 has a function of controlling the image forming apparatus in an integrated manner. As the control unit 40, a computer including a CPU, a memory such as a ROM and a RAM, an HDD (Hard Disk Drive) as an auxiliary storage device, a communication I / F unit, and the like can be used.

The control unit 40 controls each unit of the image forming apparatus (for example, the image forming unit 10, the fixing device 50, the sheet conveying unit 20, and the like), thereby executing the following processes to form a toner image on the sheet P. To do.
(1) Charge the photosensitive drums 1Y to 1K (2) Form the electrostatic latent images on the photosensitive drums 1Y to 1K by the optical writing units 3Y to 3K (3) Toner on the formed electrostatic latent images (4) The toner images on the photosensitive drums 1Y to 1K are primarily transferred to the intermediate transfer belt 6. (5) The paper P is conveyed along the conveyance path. (6) The toner image on the intermediate transfer belt 6 is transferred. Secondary transfer onto the paper P (7) The toner image transferred onto the paper P by the fixing device 50 is subjected to a fixing process.

  In relation to the present embodiment, the control unit 40 has a swing control unit and a measurement unit when functionally grasping this, and controls the swing motor 25 to control the swing process. I do.

  The control unit 40 as the swing control unit calculates the number of command pulses based on the transport position of the paper P, specifically, the amount of deviation of the paper P in the paper width direction, and according to the number of command pulses. A pulse signal is output to the oscillating motor 25. As a result, the registration roller 24 performs an initial operation, and the conveyance position of the paper P is corrected so as not to be offset. Further, the control unit 40 outputs a pulse signal to the swing motor 25 until the registration roller 24 moves to the home position after the initial operation, that is, after outputting the pulse signal corresponding to the command pulse number. As a result, the registration roller 24 performs a return operation, and the registration roller 24 exists at the home position before the next sheet P arrives. When the paper P passes the registration roller 24 during the return operation, the control unit 40 performs the return operation after releasing the nip of the registration roller 24.

  The control unit 40 as a measurement unit measures the number of pulses of the pulse signal in the return operation. That is, the number of pulses serving as a measurement value corresponds to the number of pulses included in the pulse signal output to the swing motor 25 before the registration roller 24 moves from the moving position due to the initial operation to the home position.

  Hereinafter, the concept of the swing process will be described with reference to FIG. In general, the paper P transported along the transport path is transported such that the reference position Cpp of the paper P in the paper width direction CD coincides with the reference position Cst of the transport path in the paper width direction CD. For example, the reference position of the paper P is set at the center of the paper, and the reference position Cst of the transport path is set at the machine center of the transport path. In this case, the position of the sheet P and the position of the toner image are appropriately set by setting the position of the image formed by the image forming units 10Y to 10K and the reference position Cst of the transport path satisfying a predetermined relationship. A toner image is formed on the paper P in the matched state.

  However, when the image forming apparatus is actually operated, there may be a situation where the transport position of the paper P is shifted, that is, the reference position Cpp of the paper P is deviated from the transport reference position Cst. As a result, the toner image is formed on the paper P in a state in which the position of the paper P and the position of the toner image are deviated from the ideal relationship. The misalignment of the paper P is caused, for example, when the paper P is transported over a relatively long distance, such as when the paper P is transported to the image transfer position via the refeed transport path. This can be caused by the influence of mechanical errors. In addition, the initial storage state of the paper P stored in the paper feed tray 21 can be a factor of the deviation of the paper P.

  Therefore, the control unit 40 performs a swing process and swings the registration roller 24 to correct the transport position of the paper P in the paper width direction CD. In order to perform such control, signals from the tip detection sensor 41, the offset sensor 42, the registration sensor 43, and the home position sensor 44 are input to the control unit 40.

  The leading edge detection sensor 41 is disposed between the image transfer position and the registration roller 24 (see FIG. 2), and detects the arrival of the paper P at the sensor detection position (a position that is a predetermined distance before the image transfer position). To do. The tip detection sensor 41 is, for example, a reflective optical sensor having a light emitting element and a light receiving element.

  The deviation sensor 42 is disposed between the leading edge detection sensor 41 and the registration roller 24 (see FIGS. 2 and 3), and detects the transport position of the paper P in the paper width direction CD (paper detection unit). As the deviation sensor 42, for example, a linear image sensor (for example, a CCD line sensor) in which a plurality of light emitting elements and light receiving elements arranged in parallel with each other are arranged linearly along the paper width direction CD can be used. Specifically, the deviation sensor 42 detects the transport position of the paper P by detecting the distance from the transport reference position Cst to the edge of the paper P. By this detection, the deviation direction of the paper P and the deviation amount can be detected.

  The registration sensor 37 is disposed between the registration roller 24 and the loop roller 23 (see FIG. 2), and detects the arrival of the paper P at a sensor detection position (a position in front of the registration roller 24 by a predetermined distance). .

  The home position sensor 44 is disposed in the vicinity of the registration roller 24 (see FIG. 3), and detects whether or not the position of the registration roller 24 is the home position (position detection unit). The detection result of the home position sensor 44 is referred to when the registration roller 24 is returned to the home position.

  The operation unit 60 outputs various information set by the user to the control unit 40. As the operation unit 60, for example, a touch panel capable of performing an input operation according to information displayed on the display can be used. Through the operation unit 60, the user can set printing conditions, for example, selection of the rocking mode or the non-rocking mode, the type of paper P (for example, the amount and size), the image density, and the like. Further, the control unit 40 can display various messages to the user via the operation unit 60 by controlling the operation unit 60. In other words, the operation unit 60 also functions as a notification unit that notifies various information.

  FIG. 5 is a flowchart showing a control procedure of the swing motor 25 according to the present embodiment. The processing shown in this flowchart is executed by the control unit 40 in response to a job start command.

  First, in step 10 (S10), the control unit 40 detects the transport position of the paper P by the offset sensor 42. By this detection, the control unit 40 can detect the deviation direction of the paper P and the deviation amount thereof. The detection of the transport position of the paper P by the deviation sensor 42 is executed, for example, when the leading edge of the paper P is detected by the leading edge detection sensor 35 as a trigger.

  In step 11 (S11), the control unit 40 calculates the amount of movement of the registration roller 24 in the swing operation based on the transport position of the paper P detected by the deviation sensor 42. This amount of movement is a value for correcting the deviation of the paper P as the registration roller 24 swings, and normally corresponds to the amount of deviation obtained by detection of the deviation sensor 42. Based on the calculated movement amount of the registration roller 24, the control unit 40 calculates the number of pulses of the pulse signal that needs to be output to the swing motor 25 in order to obtain the movement amount, and the calculated value Is set as the command pulse number A.

  In step 12 (S12), the control unit 40 outputs a pulse signal corresponding to the calculated command pulse number A to the swing motor 25. By the output of this pulse signal, the initial operation of the registration roller 24 is executed. Here, as one of the features of the present embodiment, the control of the swing motor 25 through the pulse signal is different in accordance with the setting contents of the control flag Flag determined in the previous calculation cycle, as will be described later. Executed.

  The control flag Flag is initially set to “0”. When the control flag Flag is set to “0”, the control unit 40 uses a reference current in which the output current of the pulse signal is set in advance when the swing motor 25 is controlled. Further, when outputting the pulse signal, the control unit 40 uses the value calculated in the calculation process of step 11 as it is as the command pulse number A.

  In step 13 (S13), the control unit 40 starts outputting a pulse signal corresponding to the return operation to the swing motor 25. When the output of such a pulse signal is started, the return operation of the registration roller 24 is started.

  In step 14 (S14), the control unit 40 starts measuring the number of pulses of the pulse signal output to the swing motor 25.

  In step 15 (S15), the control unit 40 determines whether or not the position of the registration roller 24 is the home position based on the detection result of the home position sensor 44. If the determination in step 15 is affirmative, that is, if the position of the registration roller 24 is the home position, the process proceeds to step 16 (S16). On the other hand, if a negative determination is made in step 15, that is, if the position of the registration roller 24 is not the home position, the process returns to step 15.

  In step 16, the control unit 40 ends the output of the pulse signal. When the output of the pulse signal is completed, the return operation of the registration roller 24 is completed.

  In step 17 (S17) following step 16, the control unit 40 ends the measurement of the number of pulses of the pulse signal output to the swing motor 25. As a result, the number of pulses included in the pulse signal output corresponding to the period of the return operation of the registration roller 24 is obtained as the measurement value B.

  In step 18 (S18), the control unit 40 determines whether or not the command pulse number A is larger than the measured value B. Since the actual movement amount of the registration roller 24 in the swinging operation is insufficient with respect to the theoretical movement amount corresponding to the command pulse number A, the command pulse number A becomes larger than the measured value B. As such a cause, for example, the inertia of the paper P at the time of the swinging operation of the registration roller 24 can be cited, and this tendency becomes remarkable when the thick paper is conveyed.

  If an affirmative determination is made in step 18, that is, if the command pulse number A is larger than the measured value B, the process proceeds to step 19 (S19). On the other hand, if a negative determination is made in step 18, that is, if the command pulse number A is less than or equal to the measured value B, the process proceeds to step 21 (S21).

In step 19, the control unit 40 determines whether or not the type of the paper P is thick paper. As described above, the definition of the cardboard in this step 19 refers to the paper P that causes the inertia that causes the actual movement amount of the registration roller 24 to be insufficient in the swinging operation. This corresponds to 256 g / m ² or more. If an affirmative determination is made in step 19, that is, if the type of paper P is thick paper, the process proceeds to step 20 (S20). On the other hand, if a negative determination is made in step 19, that is, if the type of paper P is not thick paper, the routine is exited.

  In step 20, the control unit 40 sets the control flag Flag to “1” in order to eliminate the difference between the command pulse number A and the measured value B. When the control flag Flag is set to “1” in step 20, the control unit 40 controls the swing motor 25 in one or both of the following two methods in the next calculation cycle. Do.

  As a first method, the control unit 40 increases the output torque of the swing motor 25 from the normal state (that is, the state where the control flag Flag is set to “0”). As a method for increasing the output torque, the output current of the pulse signal output to the swing motor 25 is increased from the reference current, or the output torque is increased by the acceleration / deceleration torque by adjusting the pulse frequency in the pulse signal. The technique of doing is mentioned.

  As a second method, the control unit 40 corrects the command pulse number A to a value increased from the value calculated in the calculation process of step 11, and performs an initial operation based on the corrected command pulse number A. Outputs the hour pulse signal.

  On the other hand, in step 21, the control unit 40 determines whether or not the measured value B is larger than the command pulse number A. Since the actual movement amount of the registration roller 24 in the swinging operation is excessive with respect to the theoretical movement amount corresponding to the command pulse number A, the measured value B becomes larger than the command pulse number A. As such a cause, for example, aged deterioration of the drive mechanism may be considered. Specifically, when the registration roller 24 stops at the end of the initial operation, the stop accuracy deteriorates due to the inertia of the registration roller 24. Or when there is an abnormal operation when moving to the home position.

  If an affirmative determination is made in step 21, that is, if the measured value B is greater than the command pulse number A, the process proceeds to step 22 (S22). On the other hand, if a negative determination is made in step 21, that is, if the measured value B and the command pulse number A are the same, the process proceeds to step 24 (S24).

  In step 22, as in step 19, the control unit 40 determines whether the type of paper P is thick paper. If an affirmative determination is made in step 22, that is, if the type of paper P is thick paper, the process proceeds to step 23 (S23). On the other hand, if a negative determination is made in step 22, that is, if the type of the paper P is not a thick paper, the present routine is exited.

  In step 23, the control unit 40 sets the control flag Flag to “2” in order to eliminate the difference between the command pulse number A and the measured value B. When the control flag Flag is set to “2” in step 23, the control unit 40 controls the swing motor 25 in one or both of the following two methods in the next calculation cycle. Do.

  As a first method, as in the case where the control flag Flag is set to “1”, the control unit 40 sets the output torque of the swing motor 25 to the normal state (that is, the control flag Flag is set to “0”). Increase the state).

  As a second method, the control unit 40 corrects the command pulse number A to a value that is less than the value calculated in the calculation process of Step 11, and based on the corrected command pulse number A, the pulse signal Is output.

  On the other hand, in step 24, the control unit 40 sets the control flag Flag to “0”.

  As described above, in this embodiment, the control unit 40 calculates the command pulse number A based on the transport position of the paper P detected by the deviation sensor 42, and swings the pulse signal corresponding to the command pulse number A. Output to the motor 25. Further, after outputting the pulse signal corresponding to the command pulse number A, the control unit 40 outputs the pulse signal to the swing motor 25 until the registration roller 24 moves to the home position based on the detection result of the home position sensor 44. . Further, the control unit 40 measures the number of pulses of the pulse signal output to the swing motor 25 as the measurement value B until the registration roller 24 moves to the home position. Then, the control unit 40 compares the command pulse number A with the measured value B, and adjusts the output torque of the swing motor 25 or the output pulse of the pulse signal.

  According to this configuration, it is possible to monitor whether or not the registration roller 24 is swinging normally by comparing the command pulse number A with the measurement value B. Can grasp whether the initial operation is abnormal or the return operation is abnormal. Then, based on the comparison between the command pulse number A and the measurement value B, the output torque of the swing motor 25 or the output pulse of the pulse signal is adjusted to eliminate the swing abnormality of the registration roller 24. The swing motor 25 can be operated. Thereby, it is possible to perform control so as to ensure the consistency between the position of the paper P and the position of the toner image.

  In the present embodiment, when the command pulse number A is larger than the measured value B, the control unit 40 increases the output torque of the swing motor 25 or increases the command pulse number A beyond the calculated value. It is corrected to.

  According to such a configuration, even if the amount of movement of the registration roller 24 during the swinging operation is insufficient due to insufficient torque of the swinging motor 25, the torque increase or the command pulse number A is calculated from the calculated value. Also, the amount of movement of the registration roller 24 can be adjusted so as to correspond to the correction amount of the paper P. Thereby, it is possible to perform control so as to ensure the consistency between the position of the paper P and the position of the toner image.

  In this embodiment, when the measured value B is larger than the command pulse number A, the control unit 40 increases the output torque of the swing motor 25 or reduces the command pulse number A from the calculated value. It is corrected to.

  According to this configuration, even if the amount of movement of the registration roller 24 during the swinging operation becomes excessive due to insufficient torque of the swinging motor 25, the torque increase or the command pulse number A is calculated. By reducing the amount, the movement amount of the registration roller 24 can be adjusted so as to correspond to the correction amount of the paper P. Thereby, it is possible to perform control so as to ensure the consistency between the position of the paper P and the position of the toner image.

  In the present embodiment, the control unit 40 adjusts the output torque of the swing motor 25 or the output pulse of the pulse signal on the condition of the preset type of paper P.

  According to such a configuration, by performing control for thick paper that is likely to cause a problem in movement of the registration roller 24, it is possible to suppress the occurrence of the problem and reduce the load on the image forming apparatus.

(Second Embodiment)
The image forming apparatus according to the second embodiment will be described below. The image forming apparatus according to the second embodiment is different from that of the first embodiment in the control contents of the swing motor 25. Hereinafter, the description overlapping with that of the first embodiment will be omitted, and hereinafter, the description will focus on the differences.

  For example, when the movement amount of the registration roller 24 in the swinging operation is smaller than a reference value (for example, 3 mm), the command pulse A and the measurement value B match, but when the movement amount is equal to or larger than the reference value. The command pulse A and the measurement value B may be different. This reference value can be obtained experimentally by actually operating the registration roller 24 corresponding to various movement amounts.

  When the movement amount of the registration roller 24 in the swing operation is calculated, if the movement amount is smaller than the reference value, the control unit 40 is in a normal form, that is, the control flag Flag is “0”. The swing motor 25 is controlled in accordance with the setting. On the other hand, when the calculated movement amount is greater than or equal to the reference value, the control unit 40 prohibits movement exceeding the reference value. Alternatively, the control unit 40 sets the control flag Flag according to the comparison between the command pulse A and the measured value B, as shown in the first embodiment, when swinging exceeding the reference value. The swing motor 25 is controlled in accordance with the setting of the control flag Flag.

  As described above, in the present embodiment, the movement range of the registration roller 24 includes the first range (for example, a range of 3 mm or more) in which the command pulse number A and the measurement value B are different, the command pulse number A and the measurement value B, And a second range (for example, a range smaller than 3 mm) exists. In this case, the controller 40 limits the movement of the registration roller 24 to the first range, or adjusts the output torque of the swing motor 25 or the pulse signal when the registration roller 24 moves to the first range. The output pulse is adjusted.

  According to such a configuration, it is possible to perform control so as to ensure the consistency between the position of the paper P and the position of the toner image while moving the image forming apparatus in a state where switching of the control mode is suppressed as much as possible. it can.

  In the present embodiment, the first range in which the command pulse number A and the measured value B are different from each other has been described as being larger than the second range in which the command pulse number A and the measured value B match. Even when the second range is larger than the first range, the above-described method can be applied.

(Third embodiment)
FIG. 5 is a flowchart showing a control procedure of the swing motor 25 according to the present embodiment. The image forming apparatus according to the second embodiment is different from that of the first embodiment in the control contents of the swing motor 25. Hereinafter, the description overlapping with that of the first embodiment will be omitted, and hereinafter, the description will focus on the differences.

  In step 30 (S30), when the control unit 40 detects the transport position of the paper P by the deviation sensor 42, the control unit 40 performs each process from step 31 (S31) to step 37 (S37). Here, since each process from step 30 to step 37 corresponds to each process from step 10 to step 18 shown in the first embodiment, a description thereof will be omitted.

  In step 38 (S38), the control unit 40 determines whether or not the command pulse number A is larger than the measured value B. Since the actual movement amount of the registration roller 24 in the swinging operation is insufficient with respect to the calculated value, the command pulse number A becomes larger than the measured value B. As such a cause, for example, the inertia of the sheet P during the swinging operation of the registration roller 24 can be cited.

  If an affirmative determination is made in step 38, that is, if the command pulse number A is greater than the measured value B, the process proceeds to step 39 (S39). On the other hand, if a negative determination is made in step 38, that is, if the command pulse number A is less than or equal to the measured value B, the process proceeds to step 40 (S40).

  In step 39 (S39), the control unit 40 controls the operation unit 60 to display the abnormality of the swinging operation as the cause of the abnormality.

  In step 40 (S40), the control unit 40 determines whether or not the measured value B is larger than the command pulse number A. The measured value B becomes larger than the command pulse number A because the actual movement amount of the registration roller 24 in the swinging operation is excessive with respect to the calculated value. As such a cause, for example, aged deterioration of the drive mechanism may be considered. Specifically, when the registration roller 24 stops at the end of the initial operation, the stop accuracy deteriorates due to the inertia of the registration roller 24. Or when there is an abnormal operation when moving to the home position.

  If an affirmative determination is made in step 40, that is, if the measured value B is greater than the command pulse number A, the process proceeds to step 41 (S41). On the other hand, if a negative determination is made in step 40, that is, if the measured value B and the command pulse number A are the same, the present routine is exited.

  In step 39 (S39), the control unit 40 controls the operation unit 60 to display the abnormality at the time of stopping the swing or the abnormality in the return operation as the cause of the abnormality.

  As described above, in this embodiment, the control unit 40 calculates the command pulse number A based on the transport position of the paper P detected by the deviation sensor 42, and swings the pulse signal corresponding to the command pulse number A. Output to the motor 25. Further, after outputting the pulse signal corresponding to the command pulse number A, the control unit 40 outputs the pulse signal to the swing motor 25 until the registration roller 24 moves to the home position based on the detection result of the home position sensor 44. . Further, the control unit 40 measures the number of pulses of the pulse signal output to the swing motor 25 as the measurement value B until the registration roller 24 moves to the home position. Then, the controller 40 monitors the swinging state of the registration roller 24 by comparing the command pulse number A with the measured value B.

  According to this configuration, the swinging state of the registration roller 24 is monitored through a comparison between the command pulse number A and the measured value B. Therefore, it is possible to monitor whether or not the registration roller 24 is swinging normally. If the registration roller 24 is not swinging normally, the swing operation is abnormal or the return operation is abnormal. Can be monitored. Thus, by referring to the monitoring result when the service person performs the repair of the failure, it becomes easy to investigate the cause of the failure, and the work efficiency can be improved.

  The image forming apparatus according to the embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention. . In this embodiment, the sheet conveyance position is corrected by swinging the registration roller. However, the sheet conveyance position (the conveyance roller other than the registration roller) before reaching the toner image transfer position is used to adjust the sheet conveyance position. It may be corrected. However, when correcting the paper transport position, it is preferably as close to the transfer position as possible, so a registration roller is preferable, but the paper transport position is corrected by a dedicated member other than the transport roller. Also good.

SC Document Reading Device 10 Image Forming Unit 10Y to 10K Image Forming Unit 20 Paper Conveying Unit 21 Paper Tray 22 Paper Feeding Unit 23 Loop Roller 24 Registration Roller 25 Swing Motor 26 Paper Discharge Tray 30 Guide Member 31 Reverse Roller 32 Preregistration Roller DESCRIPTION OF SYMBOLS 50 Fixing device 40 Control part 41 Tip detection sensor 42 Misalignment sensor 43 Registration sensor 44 Home position sensor 60 Operation part

Claims (5)

In an image forming apparatus that forms an image on a sheet conveyed along a conveyance path,
A paper correction unit configured to be swingable in a paper width direction, which is a direction perpendicular to the paper conveyance direction, starting from a preset home position, and for correcting a conveyance position of the paper in the paper width direction;
An electric motor that moves the paper correction unit along the paper width direction by rotationally driving in accordance with a pulse signal;
A paper detection unit that detects a transport position of the paper in the paper width direction;
A position detection unit for detecting whether or not the position of the paper correction unit is the home position;
The command pulse number is calculated based on the conveyance position of the paper in the paper width direction detected by the paper detection unit, and a pulse signal corresponding to the command pulse number is output to the electric motor, and the command pulse number is A swing control unit that outputs a pulse signal to the motor until the paper correction unit moves to the home position based on a detection result of the position detection unit after the output of the pulse signal;
A measuring unit that measures the number of pulses of the pulse signal output to the electric motor until the paper correction unit moves to the home position,
The swing control unit compares the command pulse number with the pulse number measured by the measurement unit, and adjusts the output torque of the electric motor or the output pulse of the pulse signal. Forming equipment.   When the command pulse number is larger than the pulse number measured by the measurement unit, the swing control unit increases the output torque of the motor, or increases the command pulse number to a value greater than the calculated value. The image forming apparatus according to claim 1, wherein correction is performed.   When the number of pulses measured by the measurement unit is larger than the command pulse number, the swing control unit increases the output torque of the motor, or reduces the command pulse number to a value less than the calculated value. The image forming apparatus according to claim 1, wherein correction is performed. The swing control unit, if the predetermined specific type of paper, the output torque of the electric motor, or the have line adjustment of the output pulse of the pulse signal, when the sheet other than the specific type which is set in advance The image forming apparatus according to claim 1 , wherein adjustment of an output torque of the electric motor or an output pulse of the pulse signal is not performed . The movement range before Symbol sheet correction unit, a first range in which the command pulses the number and said number of pulses measured by the measuring unit are different, the number of pulses measured by said measuring unit and the number of the command pulse There are two ranges corresponding to the second range , and the swing control unit restricts the movement of the sheet correction unit to the first range, or the sheet correction unit detects the first range. 5. The image forming apparatus according to claim 1, wherein the adjustment of the output torque of the electric motor or the adjustment of the output pulse of the pulse signal is performed only when moving to the position.

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