JP2013028461A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that properly holds a sheet and thereby prevents skew or wrinkles generated on the sheet even if the type of sheet is changed.SOLUTION: The image forming apparatus A includes: a rocking part 50 that conveys the sheet S while holding it, and can be moved in a direction perpendicular to in a conveyance direction of the sheet S; and an image forming part 10 that is disposed downstream the rocking part 50 to form an image on the sheet S conveyed from the rocking part 50. The rocking part 50 adjusts a pressure applied while the sheet S is being held based on the type of the sheet S.

Description

  The present invention relates to an image forming apparatus having a mechanism for aligning a printed image and paper in an electronic copying machine or the like.

  In an electrophotographic image forming apparatus, a registration roller is provided. The registration roller corrects the paper bending when the sheet is abutted against it, and swings the registration roller in a direction orthogonal to the conveyance direction to correct a positional deviation in the direction orthogonal to the conveyance direction. By correcting the misalignment, the image forming unit can form an image at an appropriate position on the paper.

  A conventional registration roller is set so that a constant high pressure is applied to the paper with reference to the thick paper so that the registration roller can be swung. A bent path is provided upstream of the registration rollers as a sheet conveyance path. If the holding pressure of the sheet in the registration roller when the sheet is swung in the direction orthogonal to the conveyance direction by the registration roller is weak, the sheet cannot be sufficiently swung due to the frictional resistance of the rear part of the sheet in contact with the bending path. Even if it is swung, it returns to the bent state due to the spring back.

  When thin paper is transported in such a state that is set at a high pressure for sandwiching thick paper, the stiffness of the thin paper is weaker than that of thick paper. The paper may wrinkle without being able to withstand.

  On the other hand, if it was set to a low pressure so as to be appropriate for the pressure for sandwiching the thin paper, when the thick paper was swung, the stiffness of the paper was too strong, and because of the frictional resistance at the rear, The swinging cannot be performed sufficiently, and the paper remains bent.

  The above problem is related to the thickness of the paper, but this also occurs for the paper size. For example, a problem similar to that of thick paper occurs in the case of a large size paper, and a problem similar to that in the case of thin paper occurs in the case of a small size paper.

  Patent Document 1 discloses a technique for releasing the pressure bonding of an upstream roller pair located upstream of a registration roller in order to prevent wrinkles caused by swinging of the registration roller.

JP 2007-022680 A

  However, the technology in Patent Document 1 does not take into account the types of paper such as thin paper and thick paper.

  For this reason, wrinkles may occur as described above if the thin paper is transported when the pressure is set at a high pressure corresponding to the thick paper as described above. On the other hand, if a low pressure is set for thin paper, thick paper may be bent when it is swung by the registration roller, or even if it is corrected, it will return to the bent state from the corrected position due to the rigidity of the paper. Sometimes. Similar to the above, the same problem occurs in the paper size.

  The present invention has been made in order to solve the above-described problem, and provides an image forming apparatus that appropriately holds a sheet and prevents the occurrence of paper bending and wrinkling even when the type of the sheet changes. Objective.

  The above object is achieved by the following means.

  (1) The paper that is conveyed while nipping the paper and that is movable in a direction orthogonal to the paper conveyance direction, and the paper that is disposed downstream of the rocking part and is conveyed from the rocking part An image forming unit that forms an image with respect to the image forming unit, wherein the swinging unit adjusts a pressure when the sheet is nipped according to a type of the sheet. .

  (2) The image forming apparatus according to (1), wherein the swinging unit adjusts the pressure based on a paper amount of the paper.

  (3) The image forming apparatus according to (1) or (2), wherein the swinging unit adjusts the pressure based on a paper size of the paper.

  (4) The swinging unit is configured to pinch a paper sheet of a paper amount or paper size greater than the predetermined reference value with a higher pressure than a paper paper amount or paper size less than a predetermined reference value. The image forming apparatus according to any one of (1) to (3).

  (5) Any one of (1) to (4), wherein the swinging unit adjusts the pressure by weighting the paper amount based on both the paper amount and the paper size of the paper. 2. The image forming apparatus according to item 1.

  According to the present invention, since the pressure for holding the paper between the registration rollers can be adjusted according to the type of paper, wrinkles and paper bending occur even when various types of paper are swung by the registration roller. Therefore, it is possible to form an image by transporting the paper downstream.

1 is a configuration diagram of an image forming apparatus according to the present invention. FIG. 6 is a plan view illustrating a state in which a registration roller corrects a positional deviation of a sheet. It is explanatory drawing at the time of adjusting the pressure between registration rollers highly. It is explanatory drawing at the time of adjusting the pressure between registration rollers low. It is explanatory drawing of the state which the registration rollers are not contacting. 3 is a flowchart of paper pressure adjustment by the image forming apparatus according to the first embodiment. 10 is a flowchart of paper pressure adjustment by the image forming apparatus according to the second embodiment. 10 is a flowchart of paper pressure adjustment by the image forming apparatus according to the third embodiment. It is the figure which determined clamping pressure based on the amount of paper sheets and paper size other than Embodiment 1-3.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(Embodiment 1)
In FIG. 1, an image forming apparatus A is called a tandem type color image forming apparatus, and performs color image formation by four sets of image forming units.

  The document placed on the document table is scanned and exposed by the scanning exposure optical system of the image reading device SC and read by the line image sensor. The photoelectrically converted image information signal is subjected to an analog signal, A / D conversion, shading correction, image compression processing, and the like in an image information processing unit (not shown), and then input to the optical writing unit of the image forming unit. The

  The four sets of image forming units are an image forming unit 10Y that forms a yellow (Y) image, an image forming unit 10M that forms a magenta (M) color image, and an image forming unit that forms a cyan (C) color image. 10C is an image forming unit 10K that forms a black (K) color image, and is denoted by reference symbols Y, M, C, and K that are formed after a common reference symbol 10, respectively.

  The image forming unit 10Y includes a photosensitive drum 1Y, 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 unit 10M includes a charging unit 2M, an optical writing unit 3M, a developing device 4M, and a drum cleaner 5M arranged around the photosensitive drum 1M, and the image forming unit 10C is arranged around the photosensitive drum 1C. The charging unit 2C, the optical writing unit 3C, the developing device 4C, and the drum cleaner 5C, and the image forming unit 10K, the charging unit 2K, the optical writing unit 3K, and the developing device 4K arranged around the photosensitive drum 1K. And a drum cleaner 5K.

  Photosensitive drums 1Y, 1M, 1C, and 1K in the image forming units 10Y, 10M, 10C, and 10K, charging units 2Y, 2M, 2C, and 2K, optical writing units 3Y, 3M, 3C, and 3K, a developing device 4Y, 4M, 4C, and 4K and drum cleaners 5Y, 5M, 5C, and 5K have the same content. In the following description, symbols Y, M, C, and K are not used unless particularly distinguished.

  The image forming unit 10 writes an image information signal on the photosensitive drum 1 in the optical writing unit 3, and forms a latent image on the photosensitive drum 1 based on the image information signal. The latent image is developed by the developing device 4 to form a visible toner image on the photosensitive drum 1.

  The photosensitive drums 1Y, 1M, 1C, and 1K in the image forming units 10Y, 10M, 10C, and 10K are respectively yellow (Y), magenta (M), cyan (C), and black (K). Images are formed.

  The intermediate transfer belt 6 is wound around a plurality of rollers and supported so as to be able to run.

  The toner images of each color formed by the image forming units 10Y, 10M, 10C, and 10K are sequentially transferred onto the traveling intermediate transfer belt 6 by the primary transfer units 7Y, 7M, 7C, and 7K, and Y (yellow), M A color image in which the respective color layers of (magenta), C (cyan), and K (black) are superimposed is formed.

  The paper S is stored in the paper feed trays 21, 22, and 23 according to the paper size such as thick paper, thin paper, or A3, A4, and has a paper feed roller 241 from any one of the paper feed trays 21 to 23. Paper is fed by the paper feeding unit 24.

  The sheet S is conveyed to the secondary transfer unit 7A through the swinging unit 50 including the loop forming roller 56 and the registration rollers 51 and 52, and the color image on the intermediate transfer belt 6 is transferred onto the sheet S. . The sheet S that has been subjected to the secondary transfer is fixed by applying heat and pressure in the fixing device 30 and discharged outside the device.

  The image forming apparatus A includes a sheet reversing unit 27. The fixed sheet S is guided from the fixing conveyance roller 25 to the sheet reversing unit 27 so as to be reversed and discharged, or image formation is performed on both sides of the sheet. It is possible.

  The operation display unit 40 installed on the upper part of the main body of the image forming apparatus A can set the type, size, number, etc. of sheets S to be used from among a plurality of sheets when performing image formation. The paper size may be detected when the original is read by the image reading device SC. In addition, transmission of signals for causing each of the above components to perform an operation is performed by the control unit 90.

  Next, with reference to FIG. 2, a process in which the swinging unit 50 according to the first embodiment conveys a sheet will be described in detail. FIG. 2 is a plan view showing how the registration rollers 51 and 52 correct the positional deviation of the paper S in the first embodiment.

  Note that a pair of registration rollers to be described later is shown in a superimposed manner for convenience of explanation. A loop forming roller pair 56 to be described later is indicated by a dotted line.

  The oscillating unit 50 is configured to oscillate the driving registration roller 51 on the back side of the paper surface in FIG. 2 and the driven registration roller 52 and the driving registration roller 51 on the front side of the paper surface in FIG. A moving motor M1, a worm wheel 53, a worm 54, and a sensor 55 for detecting the paper position are included.

  The position in the direction orthogonal to the conveyance direction of the sheet S is detected by the sensor 55, and the position information is transmitted to the control unit 90. The control unit 90 calculates a deviation amount Z from the center reference position Q of the paper S based on the position information. The drive registration roller 51 swings in a direction orthogonal to the paper transport direction based on the shift amount Z according to an instruction from the control unit 90.

  In the driving registration roller 51, for example, a worm 54 is formed on a core metal at the end.

  The worm wheel 53 that is paired with the worm 54 is connected to the swinging motor M1, and the worm wheel 53 rotates together with the swinging motor M1. The worm 54 receives rotation from the worm wheel 53 and moves in a direction orthogonal to the transport direction of the paper S. The movement of the worm 54 causes the drive registration roller 51 to swing, and the positional deviation in the direction orthogonal to the transport direction of the paper S is corrected.

  The rocking amount of the registration roller 51 is, for example, 5 mm from the center reference position Q to the left and right, and 10 mm as the total movable range.

  The registration rollers 51 and 52 convey the sheet S conveyed from the upstream loop forming roller 56 to the downstream side where the secondary transfer unit 7A is located along with the above-described swinging operation of the sheet S. The conveyance of the paper by the registration roller is performed by the driving registration roller 51 rotating and the driven registration roller 52 following the driving registration roller 51 and rotating.

  Next, an operation in which the pressure adjusting mechanism 60 of the swinging unit 50 adjusts the pressure of the paper S will be described. FIG. 3 is an explanatory diagram of the pressure adjustment mechanism 60 of the swinging unit 50 according to the first embodiment, and is a diagram when the holding pressure of the paper S is adjusted high. FIG. 4 shows the holding pressure of the paper S. FIG. 5 shows a state in which the registration rollers 51 and 52 are not in contact with each other when the adjustment is made low.

The paper clamping pressure in the first embodiment is based on a case where a paper with an A4 (210 × 297) size and a paper jam amount of 90 to 120 g / m ² is clamped. Then, the clamping pressure in this case is set to “medium”, and the clamping pressure is adjusted by the swinging unit 50 in accordance with the paper size and the like as described in the following flowchart and the like based on this case. In addition, since the thickness of the paper described above has a correlation with the amount of paper, it is often classified using the amount of paper. Therefore, in the first embodiment, the thickness of the paper is indicated by the amount of paper.

  In the first embodiment, the swinging unit 50 includes a pressure adjustment mechanism 60 that adjusts the pressure for sandwiching the paper S. The pressure adjusting mechanism 60 includes a spring 61, a cam 62, a cam shaft 63, a link member 64, a support member 65, and a pressure adjusting motor M2 that drives the cam shaft 63.

  The pressure adjustment mechanism 60 adjusts the pressure of the paper S by moving the driven registration roller 52 close to and away from the driving registration roller 51.

  A link member 64 is connected to both ends of the driven registration roller 52 in the axial direction, and the link member 64 is rotatable about the rotation shaft of the support member 65. The end of the link member 64 is in contact with the cam 62 by the contraction force of the spring 61. The cam 62 rotates around the cam shaft 63 as the cam shaft 63 rotates.

  When the cam shaft 63 rotates, the cam 62 changes the distance from the center of the cam shaft 63 to the contact surface of the link member 64. If the distance to the contact surface is short, as shown in FIG. 3, the lower part of the link member 64 in the figure is not pushed so much, and the driven registration roller 52 does not rise upward in the figure with the support member 65 as a fulcrum. As a result, the distance between the driving registration roller 51 and the driven registration roller 52 does not increase, and the clamping pressure for the paper S is high. On the other hand, as shown in FIG. 4, when the distance from the center of the cam shaft 63 to the contact surface of the link member 64 increases, the lower part of the link member 64 is pushed, and the driven registration roller 52 is separated from the drive registration roller 51. In the state shown in FIG. 4, the clamping pressure for the paper S is lower than that in the state shown in FIG. As shown in FIG. 5, when the distance from the center of the camshaft 63 to the contact surface of the link member 64 is further increased, the driven registration roller 52 is further separated from the driving registration roller 51. In the state shown in FIG. 5, the driving registration roller 51 and the driven registration roller 52 are released from the pressure bonding and do not sandwich the paper S. In this way, the link member 64 is rotated by the cam 62 with the rotation shaft of the support member 65 as a fulcrum, so that the driven registration roller 52 approaches and separates from the drive registration roller 51.

  If the driven registration roller 52 is close to the driving registration roller 51 as shown in FIG. 3, the pressure for sandwiching the paper S is increased, and conversely, if the driven registration roller 52 is separated from the driving registration roller 51 as shown in FIG. The sandwiching pressure of S becomes low.

In the pressure adjustment, the control unit 90 stores an appropriate position of the cam 62 for each type of paper S, that is, a rotational position of the pressure adjusting motor M2. For example, when the sheet S is plain paper with a paper amount of 100 g / m ² , the control unit 90 sets the rotation position of the pressure adjustment motor M2 so that the cam 62 is at the position (pressure “medium”) shown in FIG. Control. Further, when the paper S is a thin paper with a paper amount of 80 g / m ² , the rotational position of the pressure adjusting motor M2 is controlled so that the cam 62 is at the position shown in FIG. 4 (pressure “low”). An appropriate rotational position of the pressure adjusting motor M2 is stored in advance for various types of paper S such as thick paper as well as plain paper and thin paper.

  When the sheet S is conveyed to the downstream transfer device 7A or the fixing device 30, the control unit 90 controls the rotational position of the pressure adjusting motor M2 to the position of the cam 62 shown in FIG. The holding of the paper S by 52 is released.

  Next, a process in which the swinging unit 50 adjusts the clamping pressure according to the type of paper using the pressure adjusting mechanism 60 will be described. FIG. 6 is a flowchart of pressure adjustment by the registration rollers 51 and 52 according to the first embodiment. Here, a description will be given of a case where the holding pressure is adjusted based on the type of paper based on the amount of paper S.

The control unit 90 reads the paper amount (g / m ² ) of the paper selected from the operation display unit 40 from a storage device such as a ROM. In the first embodiment, the reference for the amount of paper for thin paper in the following flowchart is 90 g / m ² , and the reference for the amount of paper for thick paper is 120 g / m ² .

First, the control unit 90 determines whether the amount of paper S conveyed from any of the paper feed trays 21 to 23 is 90 g / m ² or more, which is a reference for thin paper (step S1). When the amount of paper is less than 90 g / m ² (step S1: NO), the control unit 90 controls the motor M2 so that the sandwiching pressure of the paper S is “low”, and between the registration rollers 51 and 52. The pressure is adjusted (step S2).

  When conveyance of the sheet S is started from the registration rollers 51 and 52 toward the secondary transfer unit 7A (step S3), the registration rollers 51 and 52 sandwich the sheet S with the clamping pressure adjusted in step S2, Swing is performed in a direction orthogonal to the paper transport direction (step S4). The position correction of the sheet S by swinging is completed before the sheet S is supplied to the secondary transfer unit 7A.

When the amount of paper is 90 g / m ² or more (step S1: YES), the control unit 90 determines whether the amount of paper is 120 g / m ² or more which is a standard for thick paper (step S5). When the amount of paper is less than 120 g / m ² (step S5: NO), the control unit 90 adjusts the pressure between the registration rollers 51 and 52 so that the clamping pressure of the paper S becomes “medium” (step S6). Steps S3 and S4 are executed by the pressure set in step S6.

When the paper jam amount is 120 g / m ² or more (step S5: YES), the control unit 90 adjusts the clamping pressure between the registration rollers 51 and 52 so that the clamping pressure of the sheet S becomes “high” (step S7). . Steps S3 and S4 are executed by the pressure set in step S7.

  According to the image forming apparatus according to the first embodiment, the nipping pressure is adjusted to “high” for thick paper and the nipping pressure is adjusted to “low” for thin paper based on the amount of paper jam. The rollers 51 and 52 are configured to swing. As a result, it is possible to prevent paper bending on thick paper and to prevent generation of wrinkles on thin paper, and it is possible to perform image formation by appropriately correcting the position of the paper without deteriorating the quality of the paper.

(Embodiment 2)
In the first embodiment, the case where the holding pressure of the paper S is adjusted based on the amount of paper jam of the paper has been described, but the holding pressure of the paper S can be adjusted based on the paper size.

  FIG. 7 is a flowchart of pressure adjustment by the registration rollers 51 and 52 according to the second embodiment. In the following flowchart, the length of the paper S is the length of the short side of the paper S. In the second embodiment, for example, 200 mm and 300 mm are used as the paper size standard.

  The control unit 90 acquires information on the paper size from the paper size designated from the operation display unit 40 or the original acquired by the image reading device SC, and determines whether the paper size is 200 mm or more (step S11).

  When the paper size is less than 200 mm (step S11: NO), the control unit 90 controls the motor M2 to adjust the pressure between the registration rollers 51 and 52 so that the clamping pressure of the paper S becomes “low”. (Step S12). This is the same as step S2 in the first embodiment.

  When the conveyance of the sheet S from the registration rollers 51 and 52 toward the secondary transfer unit 7A is started (step S13), the registration rollers 51 and 52 swing in a state where the nipping pressure is “low” (step S14). The position in the direction orthogonal to the transport direction of the paper S is corrected.

  When the paper size is 200 mm or more (step S11: YES), the control unit 90 determines whether the paper size is 300 mm or more (step S15). When the paper size is less than 300 mm (step S15: NO), the control unit 90 controls the motor M2 to adjust the pressure between the registration rollers 51 and 52 so that the nipping pressure is “medium” (step S16). ). This is the same as step S6 in the first embodiment. Steps S13 and S14 are executed by the pressure set in step S16.

  When the paper size is 300 mm or more (step S15: YES), the control unit 90 adjusts the clamping pressure between the registration rollers 51 and 52 so that the clamping pressure of the paper S becomes “high” (step S17). This is the same as step S7 in the first embodiment. Steps S13 and S14 are executed by the pressure set in step S17.

  The image forming apparatus according to the second embodiment is configured to adjust the holding pressure of the sheet based on the sheet size of the sheet S. Therefore, it is possible to prevent the sheet from being bent at a relatively large size such as A3, and B5. Thus, it is possible to prevent the generation of wrinkles at a small size as described above, and to appropriately form an image while maintaining the quality of the paper.

(Embodiment 3)
In the first and second embodiments, the holding pressure of the paper S is adjusted based on one of the paper jam amount and the paper size. However, the paper clamping pressure may be adjusted based on both the paper jam amount and the paper size.

  FIG. 8 is a flowchart of pressure adjustment by the registration rollers 51 and 52 according to the third embodiment. In the third embodiment, the paper size reference is only 300 mm.

First, the control unit 90 determines whether the amount of paper selected from the operation display unit 40 is 90 g / m ² or more (step S21). When the amount of paper is less than 90 g / m ² (step S21: NO), the control unit 90 determines whether the paper size of the paper S is 300 mm or more (step S22).

  When the paper size is less than 300 mm (step S22: NO), the control unit 90 controls the motor M2 to adjust the pressure between the registration rollers 51 and 52 so that the clamping pressure of the paper S becomes “low”. (Step S23). This is the same as step S2 in the first embodiment.

  When the conveyance of the sheet S from the registration rollers 51 and 52 toward the secondary transfer unit 7A is started (step S24), the registration rollers 51 and 52 swing in a state where the nipping pressure is “low” (step S25). The position in the direction orthogonal to the transport direction of the paper S is corrected.

  When the paper size is 300 mm or more (step S22: YES), the control unit 90 controls the motor M2 to adjust the pressure between the registration rollers 51 and 52 so that the clamping pressure of the paper S becomes “medium”. (Step S26). This is the same as step S6 in the first embodiment. Steps S24 and S25 are executed by the pressure set in step S26.

When the paper amount is 90 g / m ² or more (step S21: YES), the control unit 90 determines whether the paper amount is 120 g / m ² or more (step S27). When the amount of paper is less than 120 g / m ² (step S27: NO), the control unit 90 determines whether the paper size of the paper S is 300 mm or more (step S28).

  When the paper size is less than 300 mm (step S28: NO), the control unit 90 controls the motor M2 to adjust the pressure between the registration rollers 51 and 52 so that the paper clamping pressure is “medium” (step S28: NO). Step S29). This is the same as step S6 in the first embodiment. Steps S24 and S25 are executed by the pressure set in step S29.

When the paper size is 300 mm or more (step S28: YES), or when the paper jam amount of the paper S is 120 g / m ² or more (step S27: YES), the control unit 90 causes the nipping pressure of the paper S to be “high”. The clamping pressure between the registration rollers 51 and 52 is adjusted (step S30). This is the same as step S7 in the first embodiment. Steps S24 and S25 are executed by the pressure set in step S30.

  The image forming apparatus according to the third embodiment is configured to adjust the holding pressure of the paper S based on the paper amount and the paper size of the paper. Therefore, when the paper amount or the paper size is classified as medium The clamping pressure can be adjusted more accurately, and the image formation can be appropriately performed while maintaining the quality of the paper S by appropriately preventing the generation of wrinkles and paper bending.

  Further, as can be seen from the description of FIG. 8, in the third embodiment, the paper size is not divided into 200 mm and 300 mm, and the paper paper amount and paper size determine the paper holding pressure. Is set to increase the contribution rate.

  The occurrence of paper bending and wrinkling of the paper is affected by the stiffness of the paper, that is, the rigidity of the paper, and the rigidity depends on the mass and surface area of the paper. In this case, the paper size considers the surface area of the paper, but does not consider the mass.

On the other hand, in the case of the paper amount (g / m ² ), not only the surface area but also the mass is taken into consideration, so by setting the pinching pressure with a higher contribution rate (weighting) of the paper amount than the paper size. It is possible to appropriately prevent paper bending and wrinkles.

  In the above-described embodiment, the type of the paper S is distinguished by the amount of paper jam or the paper size of the paper S, and the pressure for holding the paper is adjusted. However, it is not limited to this. The type of paper may be distinguished according to the thickness and material of the paper S and the type of surface processing.

In the third embodiment, the reference value of the paper size of the paper S is only 300 mm. However, as shown in FIG. 9, two reference values of 200 mm and 300 mm may be used as in the second embodiment. I.e., less than the sheet size 200 mm, less than 200 mm 300mm, and 300mm or more, separate the paper basis weight less than ^{90g / m 2, 90g / m} 2 or more 120 g / ^m less than ^2, and 120 g / ^{m 2} or more. For example, when the paper size is 420 mm and the paper jam amount is 130 g / m ² , the clamping pressure is “high”, and when the paper size is 297 mm and the paper jam amount is 100 g / m ² , “medium”, the paper size is 182 mm and the paper jam amount is 80 g / m ² . In this case, the clamping pressure may be adjusted to “low”.

10 Image forming unit,
50 rocking part,
51 Driving registration roller,
52 Followed registration roller,
53 Worm wheel,
54 Warm,
55 sensors,
56 loop forming rollers,
60 pressure adjustment mechanism,
61 Spring,
62 cams,
63 camshaft,
64 link members,
65 support members,
M1 oscillating motor M2 pressure adjusting motor,
S paper,
Q center reference position,
Z displacement amount,
S paper.

Claims (5)

A rocking unit that conveys the sheet while sandwiching the sheet and is movable in a direction perpendicular to the sheet conveying direction;
An image forming unit that is disposed downstream of the swinging unit and forms an image on the sheet conveyed from the swinging unit,
2. The image forming apparatus according to claim 1, wherein the swinging unit adjusts a pressure when the paper is sandwiched according to a type of the paper.   The image forming apparatus according to claim 1, wherein the swinging unit adjusts the pressure based on a paper amount of the paper.   The image forming apparatus according to claim 1, wherein the swing unit adjusts the pressure based on a paper size of the paper.   The oscillating portion clamps a paper sheet having a paper amount or paper size larger than the predetermined reference value by a higher pressure than a paper sheet having a paper amount or paper size less than a predetermined reference value. The image forming apparatus according to claim 1.   The said rocking | swiveling part weights a paper amount based on both the paper amount and the paper size of the said paper, and adjusts the said pressure, The said any one of Claims 1-4 characterized by the above-mentioned. The image forming apparatus described.

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