JP2019015755A - Image forming apparatus and control method - Google Patents

Abstract

To reduce variations in sheet conveyance due to a conveying roller arranged upstream of a registration roller.SOLUTION: An image forming apparatus comprises: a registration roller 27 (swinging roller) that consists of a pair of rollers and conveys a sheet conveyed thereto toward a secondary transfer roller 9 (transfer unit); a position detection sensor SE1 (detection unit) that is arranged upstream in a sheet conveyance direction of the registration roller 27 and detects the position of a side end part of the sheet; and a control unit 11 that swings the registration roller 27 on the basis of a result of detection performed by the position detection sensor SE1 and predetermined swing control information.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus and a control method.

  In recent years, multifunctional image forming apparatuses having functions such as printers, scanners, copiers, and fax machines have been widely used. In an image forming apparatus, paper is transported from a paper feed unit or a reverse path to a transfer unit during image formation. (There is also a case of direction). When the printing process is performed in such a state where the paper is misaligned, there is a problem that the image forming position on the paper is deviated from the original proper position.

  Therefore, in order to accurately align the image and the paper in consideration of the deviation of the paper, the registration rocking that corrects the deviation of the paper by sandwiching the paper with the registration roller and swinging in the paper width direction is performed. Dynamic correction is performed. For example, in Patent Document 1, a registration roller is disposed on the upstream side of the image forming position, and a line sensor is disposed on the downstream side of the registration roller and on the upstream side of the secondary transfer roller. An image forming apparatus that corrects a deviation of a sheet by swinging the sheet in the sheet width direction based on the deviation amount of the sheet is disclosed.

JP 2013-91563 A

  However, since the conventional technology including Patent Document 1 employs a configuration in which a line sensor is arranged on the downstream side of the registration roller and the upstream side of the secondary transfer roller, the paper conveyance by the registration roller varies. It is only possible to obtain a measurement result including In other words, since it is impossible to measure variations in paper conveyance by the conveyance roller (paper feeding unit / ADU (double-sided unit)) arranged on the upstream side of the registration roller, the paper by the conveyance roller arranged on the upstream side of the registration roller. There is a problem that variation in conveyance cannot be suppressed.

  An object of the present invention is to suppress variations in paper conveyance by a conveyance roller arranged on the upstream side of a registration roller.

The invention described in claim 1 has been made to achieve the above object,
In an image forming apparatus that conveys a sheet to an image transfer position by a transfer unit and transfers the image to the sheet,
A swing roller composed of a pair of rollers for transporting the paper being transported toward the transfer unit;
A detection unit that is disposed upstream of the swing roller in the paper conveyance direction and detects the position of the side edge of the paper;
A control unit that swings the swing roller based on a detection result detected by the detection unit and predetermined swing control information;
It is characterized by providing.

According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect.
The detection unit is further disposed between the swing roller and the transfer unit.

The invention according to claim 3 is the image forming apparatus according to claim 1 or 2,
The detection unit is further disposed between the transfer unit and a fixing unit that fixes the image transferred to the paper by the transfer unit.

According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects.
The detection unit is further arranged on the downstream side in the sheet conveyance direction with respect to the fixing unit that fixes the image transferred to the sheet by the transfer unit.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects,
The swing control information is set according to a condition relating to paper conveyance.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect,
A storage unit is provided that stores a table storing the swing control information according to a condition related to sheet conveyance.

The invention described in claim 7
A swing roller composed of a pair of rollers that transports the transported paper toward the transfer section, and a detection that detects the position of the side edge of the paper disposed upstream of the swing roller in the paper transport direction. A swing roller control method in an image forming apparatus comprising:
A step of swinging the swing roller based on a detection result detected by the detection unit and predetermined swing control information.

  According to the present invention, it is possible to suppress variation in paper conveyance by the conveyance roller disposed on the upstream side of the registration roller.

1 is a configuration diagram schematically illustrating an image forming apparatus according to an embodiment. FIG. 9 is an explanatory diagram illustrating a paper swing process by a registration roller. FIG. 2 is a block diagram schematically showing a configuration of a control system of the image forming apparatus in FIG. 1. FIG. 6 is a diagram illustrating an example of a configuration in which a position detection sensor is arranged on the upstream side in the paper conveyance direction with respect to a registration roller. It is a figure which shows the example of data storage of a rocking | fluctuation control table. FIG. 10 is a diagram illustrating an example of a configuration in which position detection sensors are arranged on the upstream side in the paper conveyance direction and the downstream side in the paper conveyance direction of the registration rollers. FIG. 4 is a diagram illustrating an example of a configuration in which position detection sensors are arranged on the upstream side in the paper conveyance direction of a registration roller and on the downstream side in the paper conveyance direction of a secondary transfer roller. FIG. 6 is a diagram illustrating an example of a configuration in which position detection sensors are arranged on the upstream side in the paper conveyance direction of the registration roller and on the downstream side in the paper conveyance direction of the fixing member.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[Configuration of Image Forming Apparatus 100]
First, the configuration of the image forming apparatus 100 in the present embodiment will be described.
FIG. 1 is a configuration diagram schematically illustrating an image forming apparatus 100 according to the present embodiment. The image forming apparatus 100 is an electrophotographic image forming apparatus 100 such as a copying machine, and forms a full-color image by arranging a plurality of photoconductors facing one intermediate transfer belt in the vertical direction. This is a so-called tandem color image forming apparatus.

  The image forming apparatus 100 is mainly composed of a document reading device SC, an image forming unit 10, a fixing device 50, an image reading unit 60, and a control unit 11, and these are housed in one 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. This image signal is subjected to processing such as A / D conversion, shading correction, and compression, and then input to the control unit 11 as image data. Note that the image data input to the control unit 11 is not limited to the data read by the document reading device SC. For example, the image data is received from a personal computer connected to the image forming device 100 or another image forming device by the communication unit 13. It may be what you did.

  The image forming unit 10 includes four sets of image forming units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 6, a secondary transfer roller 9, and the like. The image forming units 10Y, 10M, 10C, and 10K are 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 that forms a cyan (C) image. The forming unit 10C includes 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 units 3Y to 3K. Is done. Further, the developing devices 4Y to 4K develop latent images on the photosensitive drums 1Y to 1K by developing with toner. Thereby, a toner image of a predetermined color corresponding to any one of yellow, magenta, cyan, and black is formed on the 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 by the secondary transfer roller 9 to the paper P conveyed at a predetermined timing by a paper conveyance unit 20 described later. The secondary transfer roller 9 is a pressure contact member that forms a nip portion (hereinafter referred to as “transfer nip portion”) by being disposed in pressure contact with the intermediate transfer belt 6.

  The paper transport unit 20 transports the paper P along the transport path of the paper P. The paper P is stored in the paper feed tray 21, and the paper P stored in the paper feed tray 21 is taken in by the paper feed unit 22 and sent out to the transport path. Alternatively, the paper P is stored in a paper feed tray included in a paper feed device (not shown) connected to the image forming apparatus 100, and the paper P held by the paper feed device forms an image from the paper feed device. By being supplied to the apparatus 100, it is sent out to the conveyance path.

  In this transport path, a plurality of transport means for transporting the paper P is provided upstream of the transfer nip portion. Each of the conveying means is composed of a pair of pressure-contacted rollers, and conveys the paper P when at least one of the rollers is rotationally driven through a driving mechanism mainly composed of an electric motor. In addition, the pair of rollers constituting the individual conveying means is configured so that the state between the rollers can be switched between a pressure contact state and a separated state.

  In the present embodiment, intermediate conveyance rollers 23 to 25, a loop roller 26, and a registration roller 27 are provided as conveyance means from the upstream side to the downstream side of the conveyance path of the paper P. In addition to the configuration of the pair of rollers, the conveyance unit can widely employ a configuration including a pair of rotating members such as a combination of belts or a combination of a belt and a roller.

  In such a transport path, the paper P fed from the paper feed tray 21 or the paper feed tray of the paper feeder is fed by a plurality of intermediate transport rollers 23 to 25 and a loop roller 26 provided from the upstream side to the downstream side. It is sequentially transported and travels along the transport path. When the leading edge of the sheet P approaches the registration roller 27, the sheet P conveyed by the intermediate conveyance rollers 23 to 25 and the loop roller 26 is abutted against the registration roller 27 in a rotation stopped state, and the loop roller 26 is predetermined. By continuing the rotation for the time, a loop is formed on the paper P. By this loop forming action, the bending of the leading edge of the paper P is corrected (skew correction).

  Next, when the registration roller 27 starts rotating at a predetermined timing so as to synchronize with the toner image carried by the intermediate transfer belt 6, the intermediate transport rollers 23 to 25 and the loop roller 26 are switched from the pressure contact state to the separated state. It is done. That is, after the loop roller 26 transitions to the separated state, the paper P is conveyed only by the registration roller 27. The registration roller 27 performs a swinging process, which will be described later, while transporting the paper P as a swinging roller, to the transfer nip portion of the intermediate transfer belt 6 as an image carrier and the secondary transfer roller 9 as a transfer portion. And the paper P are conveyed.

  FIG. 2 is an explanatory view showing the swinging process of the paper P by the registration roller 27. The registration roller 27 is configured to be able to swing in the paper width direction CD (direction perpendicular to the paper transport direction (sub-scanning direction) FD). A driving mechanism 34 mainly composed of an electric motor is connected to the registration roller 27, and can be moved in the paper width direction CD starting from a predetermined home position by being driven by the driving mechanism 34. .

  The registration roller 27 can move the conveyed paper P along the paper width direction CD by moving along the paper width direction CD in accordance with a passage period during which the paper P passes through the registration roller 27 (oscillating). processing). Thereby, the registration roller 27 adjusts the transport position of the paper P in the paper width direction CD so as to be aligned with the position of the transferred toner image. Here, the position where the side edge of the paper P should pass in the paper width direction CD is called a target position Tp. The target position Tp is optimal in the positional relationship between the paper P and the toner image if the side edge of the paper P passes through the position in the paper width direction CD (for example, the center of the paper P in the width direction). The registration roller 27 adjusts the transport position of the paper P in the paper width direction CD so that the side edge of the paper P becomes the target position Tp. To do. The position of the toner image where the positional relationship between the paper P and the toner image is optimal is called the optimal image position.

  A position detection sensor SE1 is provided in the transport path, and the operation of the registration roller 27 is controlled by the control unit 11 based on the detection results of these sensors.

  The position detection sensor SE1 is arranged between the registration roller 27 and the loop roller 26 in the transport path, and detects the arrival of the leading edge of the paper P to the detection position of the sensor (a position in front of the registration roller 27 by a predetermined distance). To detect. The detection result of the position detection sensor SE1 is used for detection of the rotation start timing of the registration roller 27 and the like.

  The position detection sensor SE1 is a detection unit that detects the position of the side edge of the paper P in the paper width direction CD. As the position detection sensor SE1, for example, a linear image sensor (for example, a CCD line sensor) in which a plurality of light receiving elements are linearly arranged along the paper width direction CD can be used. The detection result of the position detection sensor SE1 is based on the determination of the amount of movement of the registration roller 27 in the swing process and the arrival timing of the leading edge of the paper P to the transfer nip (that is, the leading edge of the paper P reaches the secondary transfer roller 9). It is used to grasp the timing of entry).

  As shown in FIG. 1 again, the fixing device 50 is a device that performs a fixing process on the paper P on which the toner image is transferred, that is, the paper P sent out from the transfer nip portion. Part) 51 (for example, a pair of rollers) and a heater for heating one or both of the fixing members 51. The fixing device 50 fixes the toner image on the paper P through the action of the pressure applied by the pair of fixing members 51 and the heat of the fixing member 51 in the conveyance process of the paper P.

  The paper P that has been subjected to fixing processing by the fixing device 50 is read by an image reading unit (ICCU) 60 and then discharged by a paper discharge roller 28 to a paper discharge tray 29 attached to the outer side surface of the housing. . When image formation is also performed on the back surface of the paper P, the paper P on which image formation has been completed on the front surface of the paper P is read by the image reading unit 60 and then conveyed to the reversing roller 31 below by the switching gate 30. Is done. 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 paper P sent out to the paper re-feed transport path is transported by a plurality of paper re-feeding transport means, and the paper P is returned to the transfer nip portion via the registration roller 27. The paper discharge roller 28, the switching gate 30, the reversing roller 31, and the refeeding transport means also constitute the paper transport unit 20 described above.

  The image reading unit 60 includes, for example, a linear image sensor (for example, a CCD line sensor), an optical system, a light source, and the like. The image reading unit 60 reads the paper P on which the toner image is transferred, and controls the obtained read image. 11 is output. In the present embodiment, the image reading unit 60 can measure the color of the toner image on the paper P, but is not particularly limited as long as at least the area of the paper P and the area of the toner image can be recognized. In the present embodiment, the image reading unit 60 is disposed downstream of the fixing device 50 and on the near side where the conveyance path is switched by the switching gate 30, but the secondary transfer roller 9 (transfer nip unit) The arrangement position is not particularly limited as long as it is a position that can read both sides of the paper P (which may be one side at a time). Of course, it may be arranged downstream of the image forming apparatus 100 as an optional device.

FIG. 3 is a block diagram schematically showing the configuration of the control system of the image forming apparatus 100 according to the present embodiment.
As shown in FIG. 3, the control unit 11 includes a storage unit 12, a communication unit 13, an operation unit 14, a document reading device SC, an image forming unit 10, a sheet conveying unit 20, a fixing device 50, an image reading unit 60, and position detection. The sensor SE1 and the environment sensor SE2 are connected. The control unit 11 includes a CPU, a RAM, and the like. The CPU of the control unit 11 reads the system program and various processing programs stored in the storage unit 12 and expands them in the RAM, and centrally controls the operations of the respective units of the image forming apparatus 100 according to the expanded programs. For example, when a job execution command is input from the operation unit 14, the control unit 11 executes a job and forms a toner image on the paper P based on image data input by the document reading device SC or the communication unit 13. Take control.

The storage unit 12 is configured by a nonvolatile semiconductor memory, an HDD (Hard Disk Drive), or the like, and stores various programs executed by the control unit 11 as well as parameters and data necessary for each unit.
For example, the storage unit 12 stores a swing control table 121 (see FIG. 5).

  The communication unit 13 includes various interfaces such as a NIC (Network Interface Card), a MODEM (Modulator-DEModulator), and a USB (Universal Serial Bus), and connects to an external device.

  The operation unit 14 outputs various information set by the user to the control unit 11. As the operation unit 14, 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 14, the user sets the printing conditions, that is, the type of paper P (for example, basis weight, size, paper quality, etc.), paper feed tray to be used, image density, magnification, presence / absence of duplex printing, and the like. be able to. Further, the user can input a job execution command and an operation instruction in the adjustment mode through the operation unit 14. The control unit 11 can display various messages to the user via the operation unit 14 by controlling the operation unit 14.

  The environment sensor SE2 includes, for example, a temperature sensor, a humidity sensor, and the like, detects the temperature and humidity in the housing of the image forming apparatus 100, and outputs the detection result to the control unit 11.

[Operation of Image Forming Apparatus 100]
Next, the operation of the image forming apparatus 100 in this embodiment will be described.
In the present embodiment, the control unit 11 of the image forming apparatus 100 performs a process of swinging the registration roller 27 based on a detection result detected by the position detection sensor SE1 and predetermined swing control information. In the present embodiment, as the swing control information, a correction value of the target position Tp of the paper P, a swing direction (+, −), and a swing speed will be described as an example.

  In the image forming apparatus 100 according to the present embodiment, the registration roller 27 is set in accordance with the passage period during which the paper P passes through itself based on the detection result detected by the position detection sensor SE1 and the predetermined swing control information. By moving along the paper width direction CD, a swing process is performed in which the conveyed paper P is moved along the paper width direction CD.

In the present embodiment, as shown in FIG. 4, the position detection sensor SE <b> 1 that detects the position of the side edge of the paper P is upstream of the registration roller 27 in the paper transport direction FD (specifically, with the registration roller 27. (Between the loop rollers 26).
As a result, the position of the side edge of the sheet P before entering the registration roller 27 can be detected, so that variations in sheet conveyance by the conveyance roller (paper feeding unit / ADU) arranged on the upstream side of the registration roller 27 are detected. Can be detected. Then, since the registration roller 27 can be swung based on the detected variation (detection result) and predetermined rocking control information, the variation in paper conveyance by the conveyance roller disposed on the upstream side of the registration roller 27 is detected. Can be suppressed.

Here, the variation in the position of the side edge of the paper P varies depending on the conditions relating to the paper conveyance (predetermined conditions that affect the paper conveyance). Therefore, the swing control information (the correction value of the target position Tp, the swing direction (+, −) and the swing speed) of the paper P is transferred to the paper in accordance with the variation in the position of the side edge of the paper P. It is necessary to change for each condition. The conditions relating to paper conveyance are, for example, conditions such as paper type, basis weight, environment (for example, temperature and humidity) of paper P, paper size (paper width, paper length), and the like. For example, if the paper type is thin paper, the paper P tends to bend more easily than plain paper or thick paper, so the correction value needs to be larger.
In the present embodiment, a table storing the swing control information is stored in the storage unit 12 for each condition relating to the sheet conveyance. That is, the swing control information is set according to the conditions relating to the sheet conveyance. FIG. 5 shows an example of a table (swing control table 121) storing the swing control information for each paper type.

In the present embodiment, the registration roller 27 is controlled to swing at a plurality of predetermined timings (referred to as swing timings), and each swing timing is stored in the swing control table 121. The swing control information used at (timing 1 to n) is stored. Here, in order to accurately write the toner image at the optimum image position on the paper P, in the swing control table 121, for each paper type, each basis weight, each environment, each paper size, or a combination thereof, It is preferable that the swing control information used at the swing timing (timing 1 to n) is stored.
As described above, by storing the swing control table 121 in the storage unit 12, the swing control information can be appropriately determined according to each condition.

  In the present embodiment, the image forming apparatus 100 has an adjustment mode, and in the adjustment mode, a correction value can be set or corrected in advance in the swing control table 121 before executing a job. For example, when an operation in the adjustment mode is instructed by the operation unit 14, the control unit 11 conveys a predetermined number of sheets P from the sheet feeding tray 21 or the sheet feeding tray of the sheet feeding device and stores them in the storage unit 12 in advance. An image is formed by the image forming units 10Y to 10K based on the image data that has been transferred, and the toner image is transferred onto the paper P by the secondary transfer roller 9. In addition, after the registration roller 27 swings, the control unit 11 causes the position detection sensor SE1 to detect the position of the side edge of the sheet P on which the toner image is transferred, and based on the detection result, the swing control information is updated. A correction value is calculated, and the calculated correction value is set or corrected in the swing control table 121. As described above, since the image forming apparatus 100 has the adjustment mode, the correction value can be set or corrected in advance in the swing control table 121 before the job is executed, and the image position with respect to the paper P from the first sheet can be set. It is possible to provide a print with good finish.

[Specific example of swing processing]
In the swing process of the present embodiment, as described above, the registration roller 27 passes the sheet P through itself based on the detection result detected by the position detection sensor SE1 and the predetermined swing control information. This is a swinging operation of the registration roller 27 that moves the conveyed paper P along the paper width direction CD by moving along the paper width direction CD according to the period.
In an example of performing the swing process of the present embodiment, the position detection sensor SE1 detects the position of the side edge of the paper P, and the target position Tp (corrected) is detected from the position of the side edge of the paper P based on the detection result. In this case, the distance (the swing amount of the registration roller 27) to the corrected target position Tp) is determined, and the registration roller 27 is swinged based on the determined swing amount (first swing processing). .
In another example of performing the swing operation of the present embodiment, after the registration roller 27 starts swinging in the paper width direction CD, the position of the side edge of the paper P is corrected by the position detection sensor SE1 to the target position Tp (corrected). If it has been detected, it is detected whether or not it has reached the corrected target position Tp), and when it has been detected that the target position Tp has been reached, the process of stopping the oscillation of the registration roller 27 (second oscillation) Processing).
In this embodiment, any swing process may be performed. Further, for example, the first swing process is performed before the leading edge of the sheet enters the secondary transfer roller 9, and the second swinging process is performed after the leading edge of the sheet enters the secondary transfer roller 9. The dynamic process may be performed.

As described above, the image forming apparatus 100 according to the present embodiment has the registration roller 27 (swinging roller) including a pair of rollers that transports the transported paper toward the secondary transfer roller 9 (transfer unit). A position detection sensor SE1 (detection unit) that is disposed upstream of the registration roller 27 in the sheet conveyance direction and detects the position of the side edge of the sheet, and a detection result of detecting the registration roller 27 by the position detection sensor SE1. And a control unit 11 that swings based on predetermined swing control information.
Therefore, according to the image forming apparatus 100 according to the present embodiment, it is possible to detect variations in the sheet conveyance by the conveyance roller (paper feeding unit / ADU (double-sided unit)) arranged on the upstream side of the registration roller 27. Further, it is possible to suppress variations in paper conveyance by the conveyance roller disposed on the upstream side of the registration roller 27.

Further, according to the image forming apparatus 100 according to the present embodiment, the swing control information is set according to the conditions relating to the sheet conveyance.
Therefore, according to the image forming apparatus 100 according to the present embodiment, the swing control information can be set for each condition related to the sheet conveyance, so that variations in the sheet conveyance can be suppressed with higher accuracy.

In addition, the image forming apparatus 100 according to the present embodiment includes the storage unit 12 that stores a table that stores the swing control information in accordance with conditions relating to paper conveyance.
Therefore, according to the image forming apparatus 100 according to the present embodiment, the swing control information can be set and stored for each condition related to the sheet conveyance, and thus the variation in the sheet conveyance can be suppressed with higher accuracy. be able to.

  As mentioned above, although concretely demonstrated based on embodiment which concerns on this invention, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.

  For example, in the above-described embodiment, the configuration in which the position detection sensor SE1 is arranged between the registration roller 27 and the loop roller 26 (see FIG. 1 and the like) is described as an example. However, the present invention is not limited to this. Absent. In other words, any configuration may be used as long as the position detection sensor SE1 is disposed upstream of the registration rollers 27 in the sheet conveyance direction FD. For example, a configuration in which the position detection sensor SE1 is disposed in the vicinity of the sheet feed tray 21 may be employed. However, when the position detection sensor SE1 detects the position of the side edge of the paper P, if a loop is formed, the reading accuracy may be reduced due to the height fluctuation of the paper P. A configuration in which the sheet P is disposed on a path that does not receive the sheet (a path on which the sheet P can be conveyed in parallel) is preferable.

Further, in the above-described embodiment, the configuration in which the position detection sensor SE1 is arranged on the upstream side of the registration roller 27 in the paper conveyance direction FD is described as an example, but the present invention is not limited to this. That is, it is sufficient that the position detection sensor SE1 is provided at least upstream of the registration roller 27 in the paper conveyance direction FD. For example, as shown in FIG. 6, in addition to the position detection sensor SE1, the registration roller A configuration in which the second position detection sensor SE11 is disposed between the secondary transfer roller 9 and the secondary transfer roller 9 may be employed.
As described above, by disposing the position detection sensor SE11 between the registration roller 27 and the secondary transfer roller 9, it is possible to detect a variation in paper conveyance by the registration roller 27. In addition, by disposing the position detection sensor SE11 as close as possible to the secondary transfer roller 9, the paper position can be accurately aligned with the image forming position by the secondary transfer roller 9.

As described above, in the swing control of the registration roller 27, when the two position detection sensors SE1 and SE11 are used, the swing operation may be determined based on the individual detection results. You may make it determine rocking | fluctuation operation | movement using two detection results. Here, the swinging operation indicates a swinging amount, a swinging direction, and a swinging speed.
For example, when the swing operation is determined based on the individual detection result, first, the registration roller 27 is swung based on the detection result of the position detection sensor SE1, and then the registration is performed based on the detection result of the position detection sensor SE11. You may make it perform the process which rocks the roller 27. FIG.
Further, for example, when the swing operation is determined based on two detection results, the inclination (sub-scanning bending) of the paper P is calculated, and the registration roller 27 is swung based on the calculated inclination of the paper P. Processing may be performed. Note that the inclination of the paper P is defined as “X1, X2 in the paper width direction” is “X1, X2” when the coordinates of the two paper conveyance directions FD at which the position of the edge of the paper is detected are X1 and X2, respectively. It can be calculated by dividing by “the transport distance between X2”. Thus, by calculating the inclination of the paper P based on the two detection results, the number of detections of the position of the paper side edge can be reduced, so that the processing speed can be improved.

For example, as shown in FIG. 7, in addition to the position detection sensor SE1, a configuration in which a second position detection sensor SE12 is arranged between the secondary transfer roller 9 and the fixing member 51 may be adopted. Good.
As described above, by disposing the position detection sensor SE12 between the secondary transfer roller 9 and the fixing member 51, it is possible to detect a variation in paper conveyance by the secondary transfer roller 9. In addition, since the image formed image can be read by arranging the position detection sensor SE12 on the downstream side of the secondary transfer roller 9, it is possible to reliably form the sheet with respect to the image forming position by the secondary transfer roller 9. The position can be adjusted.

Further, for example, as shown in FIG. 8, in addition to the position detection sensor SE <b> 1, downstream of the fixing member 51 in the sheet conveyance direction FD (specifically, “fixing member 51”, “fixing member 51 and sheet conveyance direction”). A configuration may be adopted in which the second position detection sensor SE13 is arranged between the “conveying rollers adjacent on the FD downstream side”.
As described above, by disposing the position detection sensor SE13 on the downstream side of the fixing member 51 in the paper transport direction FD, it is possible to detect variations in paper transport by the fixing member 51. In addition, by disposing the position detection sensor SE13 on the downstream side of the fixing member 51, it is possible to detect the sheet bending caused by the fixing member 51 having a particularly large conveyance pressure (nip force), so that the sheet position can be adjusted more reliably. be able to.

  In the example illustrated in FIG. 8, a configuration in which the position detection sensor SE13 is disposed between the “fixing member 51” and the “conveying roller adjacent to the fixing member 51 on the downstream side in the paper conveyance direction FD” will be described as an example. However, it is not limited to this. In other words, any configuration may be used as long as the position detection sensor SE13 is disposed downstream of the fixing member 51 in the sheet conveyance direction FD. For example, the configuration may be a configuration in which the position detection sensor SE13 is disposed in the vicinity of the paper discharge tray 29.

  In addition, as long as at least one position detection sensor SE1 is provided upstream of the registration roller 27 in the sheet conveyance direction FD, a plurality of position detection sensors may be arranged. For example, the position detection sensor SE11 (see FIG. 6), position detection sensor SE12 (see FIG. 7), and position detection sensor SE13 (see FIG. 8) may be appropriately combined and arranged.

  Further, the correction value of the target position Tp of the paper P does not need to be a position that matches the image writing center, and can be any position as long as the toner image can be finally formed at the optimum image position in the paper P. It may be. In other words, any configuration may be used as long as an image is formed on the paper P at the optimum image position when the image is printed on the paper P.

  In the above-described embodiment, the registration roller 27 is swung based on the detection result detected by the position detection sensor SE1 and predetermined swing control information. The swing control information may be corrected based on the detection result detected by the position detection sensor SE1 after the 27 swings. In this case, for example, the swing control information for the next sheet may be corrected based on the detection result for the previous sheet. For example, the swing control information on the trailing edge side of the own paper may be corrected based on the detection result on the leading edge side of the own paper.

  In the above embodiment, a color image forming apparatus that primarily transfers an image formed on a photosensitive drum to an intermediate transfer roller and transfers the image from the intermediate transfer roller to the paper P by a secondary transfer roller will be described as an example. However, the present invention can also be applied to a monochrome image forming apparatus that transfers an image directly from a photosensitive drum to a sheet P using a transfer roller.

  In the above-described embodiment, the configuration in which the registration roller 27 swings in the paper width direction CD when swinging is described as an example. However, the present invention is not limited to this. In other words, if the conveyed paper P can be moved along the paper width direction CD, the paper P swings in a direction other than the paper width direction CD (for example, a direction shifted by 5 ° from the paper width direction CD). There may be.

  In the above embodiment, the case where the swing roller is the registration roller 27 has been described as an example. However, the present invention is not limited to this, and may be a separate body from the registration roller 27, for example.

  In the above embodiment, an electrophotographic image forming apparatus is described as an example. However, the present invention is not limited to this. For example, an ink jet image forming apparatus that records an image on a recording medium by ejecting ink from a nozzle onto the recording medium and landing in a desired pattern (for example, the ink jet recording apparatus includes a predetermined energy beam). The present invention is applied to an apparatus in which ink that is cured by the above method is ejected from a nozzle and the ink on the ejected recording medium is cured by irradiating the predetermined energy ray to cure the ink on the recording medium. It is also possible.

  In the above description, an example in which a non-volatile memory, a hard disk, or the like is used as a computer-readable medium for the program according to the present invention is disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. A carrier wave is also applied as a medium for providing program data according to the present invention via a communication line.

  In addition, the detailed configuration and detailed operation of the image forming apparatus can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 11 Control part 12 Storage part 121 Swing control table 13 Communication part 14 Operation part SC Original reading apparatus 10 Image forming part 10Y, 10M, 10C, 10K Image forming unit 9 Secondary transfer roller (transfer part)
20 Paper transport unit 27 Registration roller (swing roller)
50 Fixing Device 51 Fixing Member (Fixing Unit)
60 Image reading unit SE1, SE11-13 Position detection sensor (detection unit)
SE2 Environmental sensor

Claims (7)

In an image forming apparatus that conveys a sheet to an image transfer position by a transfer unit and transfers the image to the sheet,
A swing roller composed of a pair of rollers for transporting the paper being transported toward the transfer unit;
A detection unit that is disposed upstream of the swing roller in the paper conveyance direction and detects the position of the side edge of the paper;
A control unit that swings the swing roller based on a detection result detected by the detection unit and predetermined swing control information;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the detection unit is further disposed between the swing roller and the transfer unit.   3. The image according to claim 1, wherein the detection unit is further disposed between the transfer unit and a fixing unit that fixes the image transferred to the sheet by the transfer unit. Forming equipment.   4. The apparatus according to claim 1, wherein the detection unit is further disposed on a downstream side in a sheet conveyance direction with respect to a fixing unit that fixes an image transferred to the sheet by the transfer unit. The image forming apparatus described.   The image forming apparatus according to claim 1, wherein the swing control information is set according to a condition relating to paper conveyance.   The image forming apparatus according to claim 5, further comprising a storage unit that stores a table storing the swing control information according to a condition related to sheet conveyance. A swing roller composed of a pair of rollers that transports the transported paper toward the transfer section, and a detection that detects the position of the side edge of the paper disposed upstream of the swing roller in the paper transport direction. A swing roller control method in an image forming apparatus comprising:
A control method including a step of swinging the swing roller based on a detection result detected by the detection unit and predetermined swing control information.

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