JP4818795B2 - Recording paper transport mechanism and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile machine that employs an electrophotographic system, and more particularly to a recording paper transport mechanism in a transfer unit of the image forming unit.

  2. Description of the Related Art Conventionally, an image forming apparatus adopting an electrophotographic method employs a transfer method in which transfer is performed by pressing a transfer roller toward the image carrier while sandwiching a recording sheet. In addition, as a bearing holding method for supporting the rotation axis of the transfer roller, a long hole (groove) portion for sliding (sliding) in the thickness direction of the recording paper is formed on a fixed casing side plate or the like. There are many cases of adopting a bearing holding system that supports the position while maintaining the position in the scanning direction. This is because it can be realized with a relatively simple structure. 14 shows an intermediate transfer belt 3 for forming a toner image, a secondary transfer roller 12 in contact with the intermediate transfer belt 3, and a counter roller 8 facing the secondary transfer roller 12 through the intermediate transfer belt 3. The transfer part of the image forming apparatus provided with these is shown. Here, a slide bearing 15 that supports the secondary transfer roller shaft 14 and is urged upward by a pressing spring 18 is engaged with a notch 17 (groove) formed in the main body side plate 16. The bearing 15 is slid in the vertical direction. Further, as an image forming apparatus of this type, for example, a transfer roller is held by a holding arm, and an open / close cover that can be opened and closed from the apparatus main body with a recording paper conveyance path as a boundary is provided on an intermediate transfer belt facing the transfer roller. Some guide guide grooves receive the shaft of the transfer roller (see Patent Document 1). Here, the holding arm is rotatably attached to the opening / closing cover, and the holding arm rotatably holds the shaft of the transfer roller.

  However, in the bearing holding method in which the transfer roller rotating shaft slides in the thickness direction of the recording paper, the sliding operation often deteriorates with time due to wear of the sliding portion or adhesion of foreign matters. Since it will not recover naturally unless aggressive maintenance work is performed, for example, when the leading edge of the recording paper reaches the transfer area, the bearing is not quickly slid and the recording paper is not When the tip temporarily loses its place, the speed unevenness in the sub-scanning direction is caused, which leads to a so-called jitter phenomenon (first problem).

  Further, in order to supply a transfer bias current to the transfer roller according to the bearing holding method, a gap due to sliding wear is provided in the case where an energizing means is provided that enables energization to the conductive bearing transfer means using a conductive material. Contamination may become unstable due to the occurrence of wear, adhesion of foreign particles, and foreign matter, and in particular, there is a concern that poor electrical contact due to fretting corrosion that occurs in parts that vibrate slightly while feeding power may affect transfer and cause image defects Is done.

  Therefore, there is a type that uses a bearing holding system in which a bearing is fixed to a swing arm having a rotation fulcrum on a side plate of the main body and the swing angle changes according to the thickness of paper to be conveyed. . For example, a concave portion is provided in a side plate that rotatably supports the photosensitive drum, and this concave portion is engaged with a support member (L-shaped cross section) that rotatably supports the transfer roller facing the photosensitive drum. (See Patent Document 2). Further, for example, there is one in which the transfer roller is supported by a support member having a link mechanism in order to form a gap between the transfer roller and the photosensitive drum (see Patent Document 3). Here, the support member is a substantially "<"-shaped lever body, which supports the transfer roller rotatably at one end, and is rotatably supported by engaging the center portion with one registration roller shaft. A spring that biases the support member in a direction in which the transfer roller is separated from the photosensitive drum is provided at the other end.

  According to these bearing holding methods, the deterioration with time is almost limited to the rotational wear of the fulcrum, and the conductive point is less worn by rotating the contact point, and it is easy to prevent foreign matters from being mixed. The reliability of the electrical connection is higher than that of the bearing holding method in which the rotation shaft of the transfer roller is slid.

However, depending on the position at which the rotation fulcrum is arranged, when the amount of swing (angle) according to the paper thickness is large, the contact position between the image carrier and the transfer roller is likely to change in the sub-scanning direction. Since the transfer sub-scanning position changes, a transfer failure will occur unless the nip range of the transfer portion is sufficiently widened (second problem). Furthermore, when the base fulcrum position is downstream of the transfer position, the transfer roller nips at the nip position of the transfer roller when the leading edge of the recording paper enters, and the swinging arm is likely to vibrate. It leads to defects and the jitter phenomenon (third problem).
Japanese Patent Application Laid-Open No. 2004-20574 (for example, pages 9 to 11, FIGS. 6 and 7) JP 2002-182445 A (for example, page 4, page 5, FIG. 7, FIG. 8) Japanese Patent No. 3308747 (for example, page 3, page 4, FIG. 3)

  In the conventional image forming apparatus, there is no description or suggestion about means for solving all the first to third problems described above, and there is room for further improvement.

  The present invention has been made to solve the conventional problems, and the operation of the transfer means that presses against the image carrier is less likely to deteriorate over time, and the change in the transfer position due to the paper thickness is small, and the transfer pressure is poor. Another object of the present invention is to provide a recording paper transport mechanism and an image forming apparatus that can prevent a jitter phenomenon.

A recording paper transport mechanism according to a first aspect of the present invention includes a first rotating body, a second rotating body facing the first rotating body, the first rotating body, and the second rotating body. An image carrier that holds the visible image and holds the visible image, and the first rotating body and the image carrier rotate while sandwiching a predetermined recording paper, while conveying the recording paper, A recording paper transport mechanism for transferring the visible image carried on the image carrier to the recording paper, supporting a rotation shaft of the first rotating body and rotating a rotation shaft of the second rotating body. The nip on a second straight line that is substantially orthogonal to a first straight line passing through the center and the rotational axis of the first rotating body and passes through a nip point between the image carrier and the first rotating body. An arm member that swings about a fulcrum provided upstream in the conveyance direction of the recording paper from the point, and the arm member to the image carrier Urging means for urging the urging means, and by the urging of the urging means, the first rotating body presses the image carrier and responds to the entry of the recording paper into the nip point. The arm member is configured to swing around the fulcrum.
A recording paper transport mechanism according to a second aspect of the present invention includes a first rotating body, a second rotating body facing the first rotating body, the first rotating body, and the second rotating body. An image carrier that is sandwiched between the first rotary body, the second rotary body, and a main body that rotatably supports the image carrier. The rotating body and the image carrier rotate while sandwiching a predetermined recording paper, and transfer the visible image carried on the image carrier to the recording paper while conveying the recording paper A transport mechanism that faces the image carrier and is substantially orthogonal to a first straight line passing through a rotation axis of the second rotary body and a rotation axis of the first rotary body, and the image carrier Arranged substantially parallel to the second straight line passing through the nip point between the body and the first rotating body, and supports the rotation axis of the first rotating body A support member and a first end fulcrum provided at one end of the shaft support member, which is disposed substantially parallel to the second straight line and is swingably supported with respect to the shaft support member; and the nip point And a first end fulcrum provided upstream of the first one fulcrum in the recording sheet conveyance direction so as to be swingable with respect to the main body and interlocked with the shaft support member. 1 link member and a second end fulcrum provided at one end of the shaft support member, which is disposed substantially parallel to the second straight line and is swingably supported with respect to the shaft support member. The nip point and the second one end fulcrum are supported so as to be swingable with respect to the main body at a second other end fulcrum provided upstream in the conveyance direction of the recording paper, and interlocked with the shaft support member. Urging the second link member and the shaft support member toward the image carrier And a first straight line, a third straight line passing through the first end fulcrum and the second one end fulcrum, and a first other end fulcrum and the second other end. The fourth straight line passing through the fulcrum is made substantially parallel to each other, and the shaft support member, the first link member, the second link member, and the main body use the main body as a fixed link. A parallel link mechanism is configured, and the first rotating body presses the image carrier by the urging force of the urging means, and the first rotation is performed in response to the recording paper entering the nip point. The body displaces the shaft support member against the bias of the biasing means, and the displacement of the shaft support member causes the first link member to swing around the first other end fulcrum, The second link member is configured to swing around the second other end fulcrum.
An image forming apparatus according to a third aspect of the present invention includes the recording paper conveyance mechanism according to the first aspect, and the image carrier and the first rotating body rotate while sandwiching a predetermined recording paper, while conveying the recording paper to transfer the visible image formed on the image bearing member to the recording paper, has a structure which is adapted to form an image on paper the recording.

  According to a fourth aspect of the present invention, there is provided the image forming apparatus according to the third aspect, further comprising: a vibration attenuating means for attenuating the vibration of the rotating shaft of the first rotating body caused by the swing of the arm member according to the first aspect. It has the composition provided.

  The image forming apparatus according to a fifth aspect of the present invention is the image forming apparatus according to the fourth aspect, wherein the vibration damping means attenuates the vibration amplitude of the rotation shaft of the first rotating body by elastically deforming in contact with the arm member. And the elastic deformation amount of the damper continuously increases as the amplitude increases.

The image forming apparatus according to a sixth aspect of the present invention is the image forming apparatus according to the fourth aspect, wherein the vibration damping means attenuates the vibration amplitude of the rotation shaft of the first rotating body by elastically deforming in contact with the arm member. A plurality of dampers are provided, and the elastic deformation amount of each damper changes according to the increase in the amplitude.
An image forming apparatus according to a seventh aspect of the present invention includes the recording paper transport mechanism according to the second aspect, and the image carrier and the first rotating body rotate while sandwiching a predetermined recording paper, while conveying the recording paper to transfer the visible image formed on the image bearing member to the recording paper, has a structure which is adapted to form an image on paper the recording.

  According to an eighth aspect of the present invention, there is provided an image forming apparatus according to the seventh aspect, wherein the vibration damping means attenuates the vibration of the rotary shaft of the first rotating body caused by the swinging of the shaft support member according to the second aspect. It has the composition provided with.

  The image forming apparatus according to a ninth aspect of the present invention is the image forming apparatus according to the eighth aspect, wherein the vibration damping means elastically deforms in contact with the shaft support member to thereby reduce the amplitude of vibration of the rotation shaft of the first rotating body. The damper has a damper that attenuates, and has an arrangement in which the amount of elastic deformation of the damper continuously increases as the amplitude increases.

  The image forming apparatus according to a tenth aspect of the present invention is the image forming apparatus according to the eighth aspect, wherein the vibration damping means elastically deforms in contact with the shaft support member to thereby increase the amplitude of vibration of the rotation shaft of the first rotating body. A plurality of dampers to be attenuated are provided, and an elastic deformation amount for each damper is changed in accordance with the increase in the amplitude.

  In the present invention, an image carrier for carrying a visible image and a first rotating body rotate while sandwiching a predetermined recording paper, and are carried on the image carrier while conveying the recording paper. In the configuration for transferring the visible image onto the recording paper, the second rotation of the image carrier is supported at the nip point between the image carrier and the first rotor while supporting the rotation shaft of the first rotor. Swinging about a fulcrum provided on a second straight line upstream of the recording paper transport direction, which is substantially perpendicular to the first straight line passing through the rotational axis of the body and the rotational axis of the first rotating body. An arm member that moves, and an urging means that urges the arm member toward the image carrier, and the urging force of the urging means causes the first rotating body to press the image carrier. The arm member swings about the fulcrum as the recording paper enters the nip point. The operation of the first rotator as a transfer means that presses against the image carrier is less likely to deteriorate over time, the change in the transfer position due to the paper thickness is small, and transfer pressure defects and jitter phenomena can be prevented. It is possible to provide a recording paper transport mechanism having the effect described above.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
An image forming apparatus according to a first embodiment of the present invention is shown in FIG. Here, a so-called four-tandem color printer 100 is shown as an electrophotographic image forming apparatus.

  In FIG. 1, a color printer 100 performs optical writing on the photosensitive drums 50 for each color of yellow (Y), magenta (M), cyan (C), and black (Bk) in the image forming unit 1. An optical writing unit 52 for forming an electrostatic latent image, an image forming unit 1 for visualizing the electrostatic latent image on the photosensitive drum for each color as a toner image of each color, and a photosensitive drum for each color The primary transfer unit 2 that primarily transfers the toner image to the intermediate transfer belt 3, the belt driving roller 6, the belt driven roller 7, the intermediate transfer belt 3 that is stretched over the opposing roller 8, and the belt driving roller 6 are driven. A belt driving motor 4 for transmitting the belt, a belt driving gear 5 for transmitting the driving force of the belt driving motor 4 to the belt driving roller 6, and a belt stretching roller (tension for adjusting the tension of the intermediate transfer belt 3). 9), a recording paper storage unit 51 for storing the recording paper 19, and a recording paper transporting unit (not shown) for taking out the recording paper 19 from the recording paper storage unit 51 and transporting it to the transfer position. Including a mechanism and a conveying means), a registration roller pair 10 for positioning the recording paper 19 before the transfer position, and a secondary transfer for transferring the toner image formed on the intermediate transfer belt 3 to the recording paper 19. By receiving the roller 12 and the secondary transfer roller shaft 14 with a bearing 15a, the arm 21 that rotatably supports the secondary transfer roller 12 and the recording paper 19 after the secondary transfer are pressurized and heated to record the paper. 19 includes a fixing roller pair 13 for fixing a toner image.

  Here, the arm 21 is formed in a substantially “<” shape. Specifically, it is bent at approximately 135 ° between an arm rotation fulcrum 20 and a bearing 15a, which will be described later, to form a support portion 21a and an inclined portion 21b, which will be described later. One end side of the arm 21 is pivotally supported by an arm rotation fulcrum 20 provided on a main body side plate (not shown) of the color printer 100 so as to be swingable. The arm rotation fulcrum 20 is disposed at substantially the same height as the conveyance surface of the recording paper 19. The arm rotation fulcrum 20 is downstream of the registration roller pair 10 in the conveyance direction of the recording paper 19 (hereinafter also simply referred to as “conveyance direction”) and upstream of the secondary transfer position. The other end of the arm 21 is supported by a pressing spring 18a that is compressed and attached to the main body side leaf spring receiving portion 16a of the main body side plate. Further, the other end side of the arm 21 is pressurized by the action of the pressing spring 18a. Further, a bearing 15a is fixed at the center of the arm 21, and the secondary transfer roller shaft 14 is pivotally supported by the bearing 15a. Therefore, the secondary transfer roller shaft 14 comes into contact with the bearing 15a and slides in the rotational direction, and does not slide in the vertical direction.

  The yellow image forming unit 1Y supplies a photosensitive drum 50Y as an image carrier, a charging charger 54Y for charging the photosensitive drum 50Y prior to optical writing, and yellow toner to the photosensitive drum 50Y. A toner supply unit (not shown), a cleaning blade 53Y abutted in the counter direction with respect to the rotation direction of the photosensitive drum 50Y, and a waste toner storage unit (not shown) for storing the cleaned toner particles as waste toner. And a contact charging member 55Y that is negatively charged in contact with the photosensitive drum 50Y. The optical writing unit 52Y writes a latent image (electrostatic latent image) on the charged photosensitive drum 50Y according to the image information. For example, various optical scanning devices using a polygon mirror, LED arrays, and the like can be used. Can be used. The magenta image forming unit 1M, the cyan image forming unit 1C, and the black image forming unit 1Bk have the same configuration.

  An image forming operation of the color printer 100 configured as described above will be described.

  When the color printer 100 functions as a color printing apparatus, for example, the color printer 100 performs image processing on image information in a format such as a page description language or a bitmap transferred from a computer connected via a USB cable. Convert to write data. As described above, after the writing data is converted, the image forming process is started.

  Prior to image formation, the photosensitive drum 50 starts rotating in a predetermined direction (counterclockwise direction in FIG. 1) so that the moving speed of the surface becomes a predetermined speed. Further, the charging roller 55 is rotated along with the photosensitive drum 50. At this time, an AC voltage having a predetermined DC voltage, amplitude, and frequency is applied to the core of the charging roller 55 from, for example, a charging bias application power source (not shown), and thereby the surface of the photosensitive drum 50 is made uniform. Charged.

  The light writing unit 52 performs exposure by irradiating the charged photosensitive drum 50 with laser light in accordance with write data. That is, by changing the potential of the image portion by light irradiation, a difference from the potential of the non-image portion not irradiated with light is generated, and an electrostatic latent image is formed by this potential contrast.

  The electrostatic latent image formed on the photoconductive drum 50 by the optical writing unit 52 is developed by the image forming unit 1 and is visualized on the photoconductive drum 50 as a toner image when toner particles adhere to the image unit. .

  The intermediate transfer belt 3 is conveyed in synchronization with the timing at which the toner image formed on the photosensitive drum 50 reaches the primary transfer position, which is the opposed portion of the primary transfer unit 2 and the photosensitive drum 50. The toner image on the photosensitive drum 50 is primarily transferred to the intermediate transfer belt 3 by the voltage applied to the primary transfer unit 2.

  Next, the toner image formed on the intermediate transfer belt 3 arrives at the secondary transfer position, which is a portion where the intermediate transfer belt 3 and the secondary transfer roller 12 are opposed, from the recording paper storage unit 51 in time. The recording paper 19 is conveyed, and the toner image on the intermediate transfer belt 3 is secondarily transferred to the recording paper 19 by the voltage applied to the secondary transfer roller 12. The recording paper 19 to which the toner image has been transferred is fixed by the fixing roller pair 13 and a color image is output on the recording paper 19.

On the other hand, the toner (transfer residual toner) remaining on the photosensitive drum 50 without being transferred is cleaned by the cleaning blade 53, and the surface of the photosensitive drum 50 after cleaning is used for the next image formation. Further, the toner remaining on the intermediate transfer belt 3 is also cleaned by a predetermined cleaning device (not shown), and the surface of the intermediate transfer belt 3 after cleaning is used for the next image formation.
Further, regarding the secondary transfer operation, the displacement of the contact point between the intermediate transfer belt 3 and the secondary transfer roller 12 will be described with reference to FIGS. Here, along with the movement of the recording paper 19 to the secondary transfer position, between the secondary transfer roller 12 and the intermediate transfer belt 3 in the order of FIG. 2 (a), FIG. 2 (b), and FIG. 3 (a). A gap occurs. FIG. 2A shows an initial state.

  In FIG. 2A, the recording paper 19 is conveyed from the registration roller pair 10 to the secondary transfer position. Here, the leading edge of the recording paper 19 first comes into contact with the secondary transfer roller 12 at the initial contact point 25, but is not in contact with the intermediate transfer belt 3, so no impact is generated on the intermediate transfer belt 3.

  In FIG. 2B, the leading edge of the recording paper 19 is further conveyed from the initial contact point 25 and reaches the prenip point 22 upstream of the axis center intersection 23 in the conveying direction. The axis center intersection 23 is an intersection between a line connecting the axes of the secondary transfer roller 12 and the opposing roller 8 and the recording paper transport path 11 (corresponding to the transport surface of the recording paper 19). After reaching the pre-nip point 22 in this way, the leading edge of the recording paper 19 further enters between the secondary transfer roller 12 and the intermediate transfer belt 3. Here, since the secondary transfer roller shaft 14 is supported by the bearing 15 a of the swingable arm 21, the arm 21 swings as it enters the prenip point 22. Displace to That is, the shaft center height of the secondary transfer roller shaft 14 (shown by the upper dotted line) in FIG. 2B is similarly displaced to the shaft center height of the secondary transfer roller shaft 14 (shown by the lower dotted line). In addition, the locus of the contact point (axial center intersection 23) between the secondary transfer roller 12 and the intermediate transfer belt 3 is also displaced. Due to this displacement, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3, and the impact (rotational load, speed fluctuation) on the intermediate transfer belt 3 is reduced. Further, since the rotation fulcrum 20 of the arm 21 is located upstream of the pre-nip point 22 in the conveyance direction of the recording paper 19, it does not bite (becomes self-service) and reduces the impact on the intermediate transfer belt 3.

In FIG. 3A, the leading edge of the recording paper 19 is further conveyed from the pre-nip point 22 and reaches the above-described axial center intersection 23. Here, with the approach to the shaft center intersection 23, the arm 21 swings further downward as compared with FIG. 2B, so that the shaft center of the secondary transfer roller shaft 14 is further displaced downward. (Indicated by the lower dotted line in the secondary transfer roller shaft 14 in FIG. 3A). While maintaining this displacement, the leading edge of the recording paper 19 passes through the axial center intersection 23 of the secondary transfer roller 12 and the intermediate transfer belt 3, passes through the post nip point 24, and is separated from both the secondary transfer roller 12 and the intermediate transfer belt 3. To do. During this time, secondary transfer to the recording paper 19 is performed.
Accordingly, the locus (including the case through the recording paper 19) of the contact point (corresponding to the axial center intersection 23) between the secondary transfer roller 12 and the intermediate transfer belt 3 and the fluctuation range of the contact point in the sub-scanning direction are shown in FIG. As shown in (b).

  In this embodiment, the arm rotation fulcrum 20 is arranged upstream of the secondary transfer position and at a height on the conveyance path, so that the swing angle of the arm 21 varies depending on the thickness of the recording paper 19. In this case, the variation in the sub-scanning direction of the axis center intersection 23 may be smaller than that in the conventional case. This is a solution to the second problem described above. Further, as described above, it does not become a bite-in-hand (it is not easy to learn), and the leading edge of the recording paper 19 can reach the pre-nip point 22 smoothly, which is a means for solving the first and third problems described above. .

  According to the color printer 100 according to the first embodiment of the present invention, the secondary transfer roller shaft 14 (corresponding to the rotation shaft of the first rotating body) is supported, and the intermediate transfer belt 3 (image) is supported. Recording paper as a recording medium with respect to the nip range (for example, pre-nip point 22, axial center intersection 23, and post-nip point 24) between the secondary transfer roller 12 (corresponding to the first rotating body) and the secondary transfer roller 12 The arm rotation fulcrum is urged toward the intermediate transfer belt 3 downstream of the conveyance direction 19 and further disposed upstream of the nip range in the conveyance direction and at substantially the same height as the conveyance surface of the recording paper 19. By providing an arm 21 (corresponding to an arm member) that swings as the recording paper 19 enters the nip range centering on 20, the pressing operation of the secondary transfer roller 12 against the intermediate transfer belt 3 is performed over time. Degradation Nikuku, and the change of the secondary transfer position is less due to paper thickness, and the transfer pressure fault and jitter phenomenon can be prevented. This configuration corresponds to an embodiment of the present invention according to claims 1 and 3.

  More specifically, since the secondary transfer roller shaft 14 is held by the bearing 15a of the arm 21, the secondary transfer roller shaft 14 does not slide in the vertical direction, and wear due to this sliding does not occur. Further, since the arm 21 swings around the arm rotation fulcrum 20, a gap is formed between the intermediate transfer belt 3 and the secondary transfer roller 12, so that the recording paper 19 enters the nip range. The impact (for example, rotational load, speed fluctuation) on the intermediate transfer belt 3 is alleviated. Further, since the arm rotation fulcrum 20 is upstream in the transport direction, it is not easy to bite, and the impact on the intermediate transfer belt 3 when the recording paper 19 enters the nip range can be reduced. Further, since the arm rotation fulcrum 20 is at substantially the same height as the conveyance surface of the recording paper 19, the range of fluctuation in the sub-scanning direction of the contact point between the intermediate transfer belt 3 and the secondary transfer roller 12 is smaller than that of the conventional technique. It's small. If the contact variation is large, the secondary transfer position in the transport direction (sub-scanning direction) is displaced according to the paper thickness of the recording paper 19. Therefore, in order to prevent transfer failure, the transfer nip width is increased. I need to take it. According to this embodiment, it is expected that the image quality is maintained and the reliability of the apparatus is improved. Further, in order to supply a transfer bias current to the secondary transfer roller 12, a current-carrying unit that enables power to be supplied to a conductive bearing transfer unit (for example, the secondary transfer roller 12 and the bearing 15a) using a conductive material is provided. In this case, since there is no sliding wear, the occurrence of gap play and the poor conduction due to the attachment of abrasion powder and foreign matter are reduced, and it is expected that good image transfer can be performed continuously.

  Further, according to the present embodiment, the arm 21 is substantially parallel to the transport surface of the recording paper 19 and supports the secondary transfer roller shaft 14, and the transport direction with respect to the support portion 21 a. And the inclined portion 21b that is inclined with respect to the recording paper conveyance path 11 and is supported by the arm rotation fulcrum 20, so that the intermediate transfer belts 3 and 2 as described above are supported. The variation range in the sub-scanning direction of the contact point with the next transfer roller 12 may be small.

  In the above-described embodiment, a straight line that passes through the shaft centers of the registration roller pair 10 and a straight line that passes through the shaft center of the opposing roller 8 and the shaft center of the secondary transfer roller 12 (center of the secondary transfer roller shaft 14). However, in the present invention, in addition to this, the straight line passing through the axial centers of the registration roller pair 10, the axial center of the opposing roller 8, and the axial center of the secondary transfer roller 12 ( The same effect can be obtained even if the straight line passing through the center of the secondary transfer roller shaft 14 is not parallel. For example, even when the recording paper conveyance path 11 between the axis center intersection (not shown) of the registration roller pair 10 and the axis center intersection 23 of the opposing roller 8 and the secondary transfer roller 12 has a curved line. The invention can be applied. In this case, the arm 21 (corresponding to the arm member) supports the secondary transfer roller shaft 14 (corresponding to the rotating shaft of the first rotating body) and the intermediate transfer belt 3 (corresponding to the image carrier). And the center of the secondary transfer roller shaft 14 and the rotation axis of the opposing roller 8 (corresponding to the second rotating body of the image carrier) at the intersection 23 (corresponding to the nip point) of the secondary transfer roller 12 and the secondary transfer roller 12. A straight line upstream of the recording paper 19 in the transport direction (corresponding to the second straight line) that is substantially perpendicular to a straight line (corresponding to the first straight line) passing through (corresponding to the rotational axis of the first rotating body). It has a configuration that swings around the arm rotation fulcrum 20 provided above. The non-parallel configuration corresponds to an embodiment of the present invention according to claims 1 and 3.

  In the above-described embodiment, the case where the color printer 100 is used as the image forming apparatus has been described. However, the present invention can obtain the same effect by using a copying machine, a multifunction machine, or the like. . When configuring as a copying machine or a multifunction peripheral, for example, a scanner as an image reading unit, a facsimile communication unit as an image communication unit, and a network connection unit are provided in the above configuration. Here, the image information read from the scanner, the facsimile image information received by the facsimile communication unit, or the image information acquired via the network is subjected to various image processing such as A / D conversion, MTF correction, and gradation processing. Thus, it is converted into write data.

[Second Embodiment]
Next, FIGS. 4 and 5 show the support structure in the secondary transfer portion of the image forming apparatus according to the second embodiment of the present invention. This is different from the first embodiment in that a damper 27 and a damper contact portion 26 are provided on the downstream side in the transport direction of the arm 21. Since the portions excluding the damper 27 and the damper contact portion 26 as vibration damping means are the same as those in the first embodiment, FIG. 1 is used and the same components are denoted by the same reference numerals and the description is partially omitted. .

  In FIG. 4A, a damper 27 is provided downstream in the transport direction (downstream in the transport direction of the main body side leaf spring receiving portion 16a) with respect to the above-described axial center intersection 23, and a damper contact portion is provided at the other end of the arm 21. 26 is formed. The damper contact portion 26 can swing up and down together with the secondary transfer roller shaft 14 as the arm 21 swings around the arm rotation fulcrum 20. When the secondary transfer is not performed, the damper contact portion 26 is in contact with the damper 27 in a state where the damper 27 is not deformed.

  Here, the physical properties of the damper 27 will be described. A viscoelastic material (for example, butyl rubber) is used to attenuate a repulsive force against an impact load due to compression. The damper 27 is appropriately selected according to the impact and the load and speed in the vertical direction. In order to precisely adjust the physical properties and dimensional accuracy (mounting accuracy), it is preferable that the point of action is as far as possible from the arm rotation fulcrum 20, and particularly from the axis-center intersection 23 that is the point of force. It is preferable to dispose further.

  Regarding the secondary transfer operation of the color printer 100 configured as described above, the displacement of the contact point between the intermediate transfer belt 3 and the secondary transfer roller 12 will be described with reference to FIGS. Here, with the movement of the recording paper 19 to the secondary transfer position, a gap (gap) is formed between the secondary transfer roller 12 and the intermediate transfer belt 3 in the order of FIG. 4A, FIG. 4B, and FIG. ) Occurs. In addition, the shape of the damper 27 changes in time series depending on the position of the leading edge of the recording paper 19 in the above order. FIG. 4A shows an initial state.

  In FIG. 4A, the recording paper 19 is conveyed from the registration roller pair 10 to the secondary transfer position. Here, the leading edge of the recording paper 19 first comes into contact with the secondary transfer roller 12 at the initial contact point 25, but is not in contact with the intermediate transfer belt 3, so no impact is generated on the intermediate transfer belt 3. Further, as described above, the damper 27 is in contact with the damper contact portion 26 but is not deformed.

  In FIG. 4B, the leading edge of the recording paper 19 is further conveyed from the initial contact point 25 and reaches the pre-nip point 22 upstream of the axial center intersection 23 in the conveying direction. After reaching the pre-nip point 22 in this way, the leading edge of the recording paper 19 further enters between the secondary transfer roller 12 and the intermediate transfer belt 3. Here, since the secondary transfer roller shaft 14 is supported by the bearing 15 a of the swingable arm 21, the arm 21 swings as it enters the prenip point 22. Displace to That is, the shaft center height of the secondary transfer roller shaft 14 (shown by the upper dotted line) in FIG. 4B is similarly displaced to the shaft center height of the secondary transfer roller shaft 14 (shown by the lower dotted line). Further, the locus of the contact point between the secondary transfer roller 12 and the intermediate transfer belt 3 is also displaced. Due to this displacement, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3, and the impact (rotational load, speed fluctuation) on the intermediate transfer belt 3 is reduced. Further, since the arm rotation fulcrum 20 is located upstream of the pre-nip point 22 in the conveyance direction of the recording paper 19, the arm rotation fulcrum 20 does not become so-called bite (it becomes easy to learn), and the impact on the intermediate transfer belt 3 is reduced. Further, as described above, the arm 21 swings downward, so that the damper contact portion 26 pushes down the damper 27, and the shape changes like the damper 27a. That is, the shape is swollen in the width direction as the height dimension is shortened. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14.

  In FIG. 5, the leading edge of the recording paper 19 is further conveyed from the pre-nip point 22 and reaches the above-described axial center intersection 23. Here, with the approach to the shaft center intersection 23, the arm 21 swings further downward as compared with FIG. 4B, so that the shaft center of the secondary transfer roller shaft 14 is further displaced downward. (Indicated by the lower dotted line in the secondary transfer roller shaft 14 of FIG. 5). While maintaining this displacement, the recording paper 19 passes through the nip between the secondary transfer roller 12 and the intermediate transfer belt 3, and secondary transfer to the recording paper 19 is performed here. Further, as described above, when the arm 21 further swings downward, the damper contact portion 26 further pushes down the damper 27, and the shape changes like the damper 27b. That is, the shape is swollen in the width direction as the height dimension is further shortened. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14. The leading edge of the recording paper 19 reaches the axial center intersection 23 and then moves away from both the secondary transfer roller 12 and the intermediate transfer belt 3 through the post nip point 24.

  According to such a color printer 100 according to the second embodiment of the present invention, the vibration of the secondary transfer roller shaft 14 caused by the swing of the arm 21 downstream of the secondary transfer roller 12 in the transport direction. By providing a damper 27 (corresponding to a vibration damping means) that attenuates the vibration, the vibration shock of the secondary transfer roller 12 due to the nip of the recording paper 19 can be attenuated. This configuration corresponds to an embodiment of the present invention according to claim 4.

[Third Embodiment]
Next, FIGS. 6 and 7 show the support structure in the secondary transfer portion of the image forming apparatus according to the third embodiment of the present invention. This is different from the second embodiment in that the damper 271 (corresponding to 27 in FIG. 4) and the damper contact portion 26 are not in contact when the recording paper 19 has not reached the secondary transfer portion. is doing. The portions excluding the damper 271 and the damper contact portion 26 as the vibration damping means are the same as those in the first embodiment. Therefore, FIG. 1 is used and the same reference numerals are given to the same components and the description is partially omitted. .

  In FIG. 6A, a damper 271 is provided downstream in the transport direction (downstream in the transport direction of the main body side leaf spring receiving portion 16a) with respect to the above-described axial center intersection 23, and a damper contact portion is provided at the other end of the arm 21. 26 is formed. The damper contact portion 26 can swing up and down together with the secondary transfer roller shaft 14 as the arm 21 swings around the arm rotation fulcrum 20. Further, when the secondary transfer is not performed, the damper contact portion 26 is separated from the damper 271 at a predetermined interval. Note that the second embodiment is applied to the physical properties of the damper 271.

  Regarding the secondary transfer operation of the color printer 100 configured as described above, the displacement of the contact point between the intermediate transfer belt 3 and the secondary transfer roller 12 will be described with reference to FIGS. Here, with the movement of the recording paper 19 to the secondary transfer position, a gap (gap between the secondary transfer roller 12 and the intermediate transfer belt 3 in the order of FIG. 6A, FIG. 6B, and FIG. ) Occurs. In addition, the shape of the damper 271 changes in time series according to the leading end position of the recording paper 19 in the above order. FIG. 6A shows an initial state.

  In FIG. 6A, the recording paper 19 is conveyed from the registration roller pair 10 to the secondary transfer position. Here, the leading edge of the recording paper 19 first comes into contact with the secondary transfer roller 12 at the initial contact 25, but is not in contact with the intermediate transfer belt 3, so that no impact is generated on the intermediate transfer belt 3. No deformation.

  In FIG. 6B, the leading edge of the recording paper 19 is further conveyed from the initial contact point 25 and reaches the prenip point 22 upstream of the axial center intersection 23 in the conveying direction. After reaching the pre-nip point 22 in this way, the leading edge of the recording paper 19 further enters between the secondary transfer roller 12 and the intermediate transfer belt 3. Here, since the secondary transfer roller shaft 14 is supported by the bearing 15 a of the swingable arm 21, the arm 21 swings as it enters the prenip point 22, and the downward direction in FIG. Displace to That is, the shaft center height of the secondary transfer roller shaft 14 (shown by the upper dotted line) in FIG. 6B is similarly displaced to the shaft center height of the secondary transfer roller shaft 14 (shown by the lower dotted line). Further, the locus of the contact point between the secondary transfer roller 12 and the intermediate transfer belt 3 is also displaced. Due to this displacement, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3, and the impact (rotational load, speed fluctuation) on the intermediate transfer belt 3 is reduced. Further, since the arm rotation fulcrum 20 is located upstream of the pre-nip point 22 in the conveyance direction of the recording paper 19, the arm rotation fulcrum 20 does not become so-called bite (it becomes easy to learn), and the impact on the intermediate transfer belt 3 is reduced. Further, as described above, when the arm 21 swings downward, the damper contact portion 26 swings downward and contacts the damper 271, but the damper 271 is not deformed.

  In FIG. 7, the leading edge of the recording paper 19 is further conveyed from the pre-nip point 22 and reaches the above-described axial center intersection 23. Here, with the approach to the shaft center intersection 23, the arm 21 swings further downward as compared with FIG. 6B, so that the shaft center of the secondary transfer roller shaft 14 is further displaced downward. (Indicated by the lower dotted line in the secondary transfer roller shaft 14 of FIG. 7). While maintaining this displacement, the recording paper 19 passes through the nip between the secondary transfer roller 12 and the intermediate transfer belt 3, and secondary transfer to the recording paper 19 is performed here. Further, as described above, when the arm 21 swings downward, the damper contact portion 26 pushes down the damper 271 and the shape changes like the damper 271a. That is, the shape is swollen in the width direction as the height dimension is shortened. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14 (shown in FIG. 7). The leading edge of the recording paper 19 reaches the axial center intersection 23 and then moves away from both the secondary transfer roller 12 and the intermediate transfer belt 3 through the post nip point 24.

  The color printer 100 according to the third embodiment of the present invention includes the damper 271 that damps the amplitude of vibration of the secondary transfer roller shaft 14 by elastic deformation in contact with the arm 21, In the state, the damper 271 and the damper contact portion 26 are not in contact with each other, and the damper 271 and the damper contact portion 26 are in contact with each other according to the increase in the amplitude, so that the amount of elastic deformation continuously increases. The distance between the damper 271 and the damper contact portion 26 can be set so as to attenuate the amplitude only when the thickness is less than a predetermined paper thickness, and the vibration damping effect is not manifested and only when the thickness is thicker than the predetermined paper thickness. This configuration corresponds to an embodiment of the present invention according to claim 5.

[Fourth Embodiment]
Next, FIGS. 8 and 9 show the support structure in the secondary transfer portion of the image forming apparatus according to the fourth embodiment of the present invention. This is different from the second embodiment in that the damper 272 is formed in a substantially conical shape. The portions excluding the damper 272 and the damper contact portion 26 as the vibration damping means are the same as those in the first embodiment. Therefore, FIG. 1 is used and the same components are denoted by the same reference numerals and the description is partially omitted. .

  In FIG. 8A, a damper 272 is provided downstream in the transport direction (downstream in the transport direction of the main body side leaf spring receiving portion 16a) with respect to the above-mentioned axial center intersection 23, and a damper contact portion is provided at the other end of the arm 21. 26 is formed. The damper contact portion 26 can swing up and down together with the secondary transfer roller shaft 14 as the arm 21 swings around the arm rotation fulcrum 20. When the secondary transfer is not performed, the damper contact portion 26 is in contact with the damper 272 in a state where the damper 272 is not deformed.

  Here, regarding the shape of the damper 272, the damper sectional shape shown in the second embodiment is substantially rectangular, whereas the damper sectional shape shown in the present embodiment is substantially triangular. That is, the thickness changes from the upper end to the lower end. Due to this triangular shape, the damper effect gradually increases as the swing of the arm 21 increases. This is because the swing angle of the arm 21 changes according to the matrix of the thickness of the recording paper 19 and the sub-scanning position, so that the vibration impact of the secondary transfer roller 12 is optimally adjusted according to this change. In order to achieve this, the damping rate by the damper 272 is appropriately and continuously inclined according to the stroke. In this embodiment, the upper end of the damper 272 is in contact with the damper contact portion 26 in the initial state (the recording paper 19 is not nipped between the intermediate transfer belt 3 and the secondary transfer roller 12). For example, the third embodiment may be applied to make non-contact.

  Regarding the secondary transfer operation of the color printer 100 configured as described above, the displacement of the contact point between the intermediate transfer belt 3 and the secondary transfer roller 12 will be described with reference to FIGS. Here, with the movement of the recording paper 19 to the secondary transfer position, a gap (gap) is formed between the secondary transfer roller 12 and the intermediate transfer belt 3 in the order of FIG. 8A, FIG. 8B, and FIG. ) Occurs. Further, the shape of the damper 272 changes in time series according to the position of the leading edge of the recording paper 19 in the above order. FIG. 8A shows an initial state.

  In FIG. 8A, the recording paper 19 is conveyed from the registration roller pair 10 to the secondary transfer position. Here, the leading edge of the recording paper 19 first comes into contact with the secondary transfer roller 12 at the initial contact point 25, but is not in contact with the intermediate transfer belt 3, so no impact is generated on the intermediate transfer belt 3. Further, as described above, the damper 272 is in contact with the damper contact portion 26, but is not deformed.

  In FIG. 8B, the leading edge of the recording paper 19 is further conveyed from the initial contact point 25 and reaches the pre-nip point 22 upstream of the axial center intersection 23 in the conveying direction. After reaching the pre-nip point 22 in this way, the leading edge of the recording paper 19 further enters between the secondary transfer roller 12 and the intermediate transfer belt 3. Here, since the secondary transfer roller shaft 14 is supported by the bearing 15 a of the swingable arm 21, the arm 21 swings as it enters the prenip point 22. Displace to That is, the axial center height (indicated by the upper dotted line) of the secondary transfer roller shaft 14 in FIG. 8B is similarly displaced to the axial center height (indicated by the lower dotted line) of the secondary transfer roller shaft 14. Further, the locus of the contact point between the secondary transfer roller 12 and the intermediate transfer belt 3 is also displaced. Due to this displacement, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3, and the impact (rotational load, speed fluctuation) on the intermediate transfer belt 3 is reduced. Further, since the arm rotation fulcrum 20 is located upstream of the pre-nip point 22 in the conveyance direction of the recording paper 19, the arm rotation fulcrum 20 does not become so-called bite (it becomes easy to learn), and the impact on the intermediate transfer belt 3 is reduced. Further, as described above, the arm 21 swings downward, so that the damper contact portion 26 pushes down the damper 272, and the shape changes like the damper 272a. That is, it becomes a shape bulging in the width direction (substantially triangular) as the height dimension is shortened. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14.

  In FIG. 9, the leading edge of the recording paper 19 is further conveyed from the pre-nip point 22 and reaches the above-described axial center intersection 23. Here, with the approach to the shaft center intersection 23, the arm 21 swings further downward as compared with FIG. 8B, so that the shaft center of the secondary transfer roller shaft 14 is further displaced downward. (Indicated by the lower dotted line in the secondary transfer roller shaft 14 of FIG. 9). While maintaining this displacement, the recording paper 19 passes through the nip between the secondary transfer roller 12 and the intermediate transfer belt 3, and secondary transfer to the recording paper 19 is performed here. Further, as described above, the arm 21 further swings downward, so that the damper contact portion 26 further pushes down the damper 272a, and the shape changes like the damper 272b. That is, the shape is swollen in the width direction as the height dimension is further shortened. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14. The leading edge of the recording paper 19 reaches the axial center intersection 23 and then moves away from both the secondary transfer roller 12 and the intermediate transfer belt 3 through the post nip point 24.

  According to such a color printer 100 according to the fourth embodiment of the present invention, the cross-sectional shape is substantially triangular in which the amplitude of vibration of the secondary transfer roller shaft 14 is attenuated by elastic deformation in contact with the arm 21. Since the damper 272 is provided and the amount of elastic deformation of the damper 272 gradually increases with the increase in the amplitude, the vibration impact on the secondary transfer roller 12 is optimized, so that the vibration attenuation rate depends on the stroke. Can be continuously inclined. This configuration corresponds to an embodiment of the present invention according to claim 5.

[Fifth Embodiment]
Next, FIGS. 10 and 11 show the support structure in the secondary transfer portion of the image forming apparatus according to the fifth embodiment of the present invention. This is different from the second embodiment in that a plurality of dampers 273, 274, and 275 having different heights (corresponding to the distance from the damper contact portion 26) are provided. The portions excluding the dampers 273, 274, 275 as the vibration damping means and the damper contact portion 26 are the same as those in the first embodiment. Therefore, FIG. Some are omitted.

  In FIG. 10A, three dampers 273, 274, 275 having different heights are sequentially provided downstream in the transport direction from the above-described axial center intersection 23 (downstream in the transport direction of the main body side leaf spring receiving portion 16a), and A damper contact portion 26 is formed at the other end of the arm 21. The damper contact portion 26 can swing up and down together with the secondary transfer roller shaft 14 as the arm 21 swings around the arm rotation fulcrum 20. When the secondary transfer is not performed, the damper contact portion 26 is in contact with the damper 273 in a state where one damper 273 is not deformed. Similarly, the damper contact portion 26 is separated from the other two dampers 274 and 275.

  Here, the shapes of the three dampers 273, 274, and 275 will be described. The second embodiment is applied so that the cross-sectional shape is substantially rectangular, and the three dampers are formed so as to have different heights. That is, the height of the damper 273, the damper 274, and the damper 275 decreases in order. Due to the difference in height, the damper effect increases stepwise as the swing of the arm 21 increases. This is because the swing angle of the arm 21 changes according to the matrix of the thickness of the recording paper 19 and the sub-scanning position, so that the vibration impact of the secondary transfer roller 12 is optimally adjusted according to this change. Thus, the attenuation rate by the damper 272 is updated stepwise as appropriate according to the stroke. In this embodiment, the upper end of the damper 273 is in contact with the damper contact portion 26 in the initial state (the recording paper 19 is not nipped between the intermediate transfer belt 3 and the secondary transfer roller 12). For example, all of the three dampers 273, 274, and 275 may be non-contact in the initial state.

Regarding the secondary transfer operation of the color printer 100 configured as described above, the displacement of the contact point between the intermediate transfer belt 3 and the secondary transfer roller 12 will be described with reference to FIGS. Here, with the movement of the recording paper 19 to the secondary transfer position, a gap (gap) is formed between the secondary transfer roller 12 and the intermediate transfer belt 3 in the order of FIG. 10A, FIG. 10B, and FIG. ) Occurs. Further, the shapes of the dampers 273, 274, and 275 and the contact state with the damper contact portion 26 change in time series according to the leading end position of the recording paper 19 in the above order. FIG. 10A shows an initial state.
In FIG. 10A, the recording paper 19 is conveyed from the registration roller pair 10 to the secondary transfer position. Here, the leading edge of the recording paper 19 first comes into contact with the secondary transfer roller 12 at the initial contact point 25, but is not in contact with the intermediate transfer belt 3, so no impact is generated on the intermediate transfer belt 3. Further, as described above, the damper 273 is in contact with the damper contact portion 26 but is not deformed. Further, the dampers 274 and 275 are separated from the damper contact portion 26.

  In FIG. 10B, the leading edge of the recording paper 19 is further conveyed from the initial contact point 25 and reaches the pre-nip point 22 upstream of the axial center intersection 23 in the conveying direction. After reaching the pre-nip point 22 in this way, the leading edge of the recording paper 19 further enters between the secondary transfer roller 12 and the intermediate transfer belt 3. Here, since the secondary transfer roller shaft 14 is supported by the bearing 15 a of the swingable arm 21, the arm 21 swings as it enters the prenip point 22. Displace to That is, the shaft center height of the secondary transfer roller shaft 14 (shown by the upper dotted line) in FIG. 10B is similarly displaced to the shaft center height of the secondary transfer roller shaft 14 (shown by the lower dotted line). Further, the locus of the contact point between the secondary transfer roller 12 and the intermediate transfer belt 3 is also displaced. Due to this displacement, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3, and the impact (rotational load, speed fluctuation) on the intermediate transfer belt 3 is reduced. Further, since the arm rotation fulcrum 20 is located upstream of the pre-nip point 22 in the conveyance direction of the recording paper 19, the arm rotation fulcrum 20 does not become so-called bite (it becomes easy to learn), and the impact on the intermediate transfer belt 3 is reduced. Further, as described above, the arm 21 swings downward, so that the damper contact portion 26 pushes down the damper 273, and the shape changes like the damper 273a. That is, the shape is swollen in the width direction as the height dimension is shortened. Further, as described above, the arm 21 swings downward, so that the damper contact portion 26 contacts the damper 274. Here, the shape of the damper 274 does not change. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14 in FIG.

  In FIG. 11, the leading edge of the recording paper 19 is further conveyed from the pre-nip point 22 and reaches the above-described axial center intersection 23. Here, with the approach to the shaft center intersection 23, the arm 21 swings further downward as compared with FIG. 10B, so that the shaft center of the secondary transfer roller shaft 14 is further displaced downward. (Indicated by the lower dotted line in the secondary transfer roller shaft 14 in FIG. 10). While maintaining this displacement, the recording paper 19 passes through the nip between the secondary transfer roller 12 and the intermediate transfer belt 3, and secondary transfer to the recording paper 19 is performed here. Further, as described above, the arm 21 further swings downward, so that the damper contact portion 26 further pushes down the dampers 273a, 274, 275 in sequence, and the shape changes like the dampers 273a, 274a, 275a. That is, the shape is swollen in the width direction as the height dimension is further shortened. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14 in FIG. The leading edge of the recording paper 19 reaches the axial center intersection 23 and then moves away from both the secondary transfer roller 12 and the intermediate transfer belt 3 through the post nip point 24.

  According to the color printer 100 according to the fifth embodiment of the present invention, a plurality of dampers 273, 274, which attenuate the amplitude of vibration of the secondary transfer roller shaft 14 by elastic deformation in contact with the arm 21, In the initial state, the damper contact portion 26 contacts only with the damper 273, and the heights of the dampers 273, 274, 275 are different from each other, and the amount of elastic deformation for each damper increases according to the increase in the amplitude. By changing, the vibration impact on the secondary transfer roller 12 is optimized, so that the vibration attenuation rate can be updated in three stages according to the stroke. This configuration corresponds to an embodiment of the present invention according to claim 6.

[Sixth Embodiment]
Next, FIG. 12 shows a support structure in the secondary transfer portion of the image forming apparatus according to the sixth embodiment of the present invention. This is different from the first embodiment in that a shaft support portion 28 that supports the secondary transfer roller shaft 14 instead of an arm that pivotally supports the secondary transfer roller 12 and a link member that interlocks with the shaft support portion 28. (Upper link 33, lower link 34) and a link mechanism (a four-link equal length link mechanism) is provided. The shaft support portion 28 corresponds to a part of the arm (for example, 21 in FIG. 11). Since the part excluding the link mechanism is the same as that of the first embodiment, FIG. 1 is used and the same reference numerals are given to the same components and the description is partially omitted.

  In FIG. 12A, the shaft support portion 28 has a configuration that rotatably supports the secondary transfer roller 12 by receiving the secondary transfer roller shaft 14 with a bearing 15a. Here, a fulcrum 30 of the upper link 33 and a fulcrum 32 of the lower link 34 are provided on one end side (right side in the drawing) of the shaft support portion 28, and the upper link 33 and the lower link 34 are supported so as to be swingable. ing. The other end side (left side in the figure) of the shaft support portion 28 is supported by a pressing spring 18a that is compressed and attached to the main body side leaf spring receiving portion 16a of the main body side plate, and is pressurized by the action of the pressing spring 18a. The

12A, the other end side (the right side in the figure) of the upper link 33 is swingably supported by a fulcrum 29 provided on a main body side plate (not shown) as the main body of the color printer 100. Yes. One end side (left side in the figure) of the upper link 33 is supported so as to be swingable around a fulcrum 30 provided on one end side (right side in the figure) of the shaft support portion 28 as described above. The other end side (right side in the figure) of the lower link 34 is swingably supported by a fulcrum 31 provided on a main body side plate (not shown) of the color printer 100. One end side (left side in the figure) of the lower link 34 is supported so as to be swingable around a fulcrum 32 provided on one end side (right side in the figure) of the shaft support portion 28 as described above. Here, the length of the upper link 33 (corresponding to the distance between the fulcrum 29 and the fulcrum 30) is equal to the length of the lower link 34 (corresponding to the distance between the fulcrum 31 and the fulcrum 32). The upper link 33 and the lower link 34 form a four-link equal length link mechanism. Compared to other mechanisms, the link mechanism is superior in that it has a complicated structure but less wear loss.

  The longitudinal direction of the upper link 33 and the lower link 34 is substantially parallel to the conveyance surface of the recording paper 19 (corresponding to the recording paper conveyance path 11). Further, the fulcrum 29 of the upper link 33 and the fulcrum 31 of the lower link 34 are on a substantially vertical line, and the straight line passing through the fulcrum 29 and the fulcrum 31 is orthogonal to the recording paper conveyance path 11. Further, the fulcrum 30 of the upper link 33 and the fulcrum 32 of the lower link 34 are also on a substantially vertical line, and the straight line passing through the fulcrum 30 and the fulcrum 32 is orthogonal to the recording paper transport path 11. All of the fulcrums 29, 30, 31, and 32 are downstream of the registration roller pair 10 in the transport direction and upstream of the secondary transfer position in the transport direction. Here, the upper link 33 and the lower link 34 are close to each other, and in FIG. 12A, pass through the secondary transfer roller shaft 14 and parallel to the recording paper conveyance path 11 (indicated by a one-dot chain line). Since the fulcrum 29 and the fulcrum 31 and the fulcrum 30 and the fulcrum 32 are line symmetric, it can be said that the fulcrums 29, 30, 31, and 32 are substantially at the same height as the secondary transfer roller shaft 14. However, the present invention is not limited to this (without specifying the heights of the fulcrums 29, 30, 31, 32), and the same effects as those of the first to fifth embodiments can be obtained. Furthermore, by using the link mechanism, an effect that the degree of freedom of design is higher than that of the first to fifth embodiments can be obtained.

  Regarding the secondary transfer operation of the color printer 100 configured as described above, the displacement of the contact point between the intermediate transfer belt 3 and the secondary transfer roller 12 will be described with reference to FIG. Here, with the movement of the recording paper 19 to the secondary transfer position, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3 in the order of FIG. 12A and FIG. . FIG. 12A shows an initial state.

  In FIG. 12A, the recording paper 19 is conveyed from the registration roller pair 10 to the secondary transfer position. Here, the leading edge of the recording paper 19 first comes into contact with the secondary transfer roller 12 at the initial contact point 25, but is not in contact with the intermediate transfer belt 3, so no impact is generated on the intermediate transfer belt 3.

Although not shown in detail, thereafter, the leading edge of the recording paper 19 is further conveyed from the initial contact point 25 and reaches the pre-nip point 22 upstream of the axial center intersection 23 in the conveying direction. After reaching the pre-nip point 22 in this way, the leading edge of the recording paper 19 further enters between the secondary transfer roller 12 and the intermediate transfer belt 3. Here, since the secondary transfer roller shaft 14 is supported by the bearing 15 a of the swingable shaft support portion 28, the upper link 33 and the lower link 34 swing as the prenip point 22 enters. Thus, the secondary transfer roller 12 is also displaced downward. That is, the upper link 33 and (in the figure, left) one end side of the lower link 34 swings downward about the fulcrum 29 and 31, the shaft support portion 28 which is swingably supported on the pivot 30, 32 Swings downward. Due to the displacement of the secondary transfer roller shaft 14, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3, and the impact (rotational load, speed fluctuation) on the intermediate transfer belt 3 is reduced. . Further, since the link fulcrums 29, 30, 31, 32 are located upstream of the pre-nip point 22 in the conveyance direction of the recording paper 19, they do not become so-called bite (learning) and reduce the impact on the intermediate transfer belt 3. Will do.

Further, in FIG. 12B, the leading edge of the recording paper 19 is further conveyed from the pre-nip point 22 and reaches the above-described axial center intersection 23. Here, as the shaft center intersects with the shaft 23, the shaft support 28 swings further downward as compared with the approach to the prenip point 22 (not shown), whereby the shaft of the secondary transfer roller shaft 14 is moved. The core is also displaced further downward (the position of the lower dotted line on the secondary transfer roller shaft 14 in FIG. 12B). Further, the locus of the contact point between the secondary transfer roller 12 and the intermediate transfer belt 3 is also displaced. Ie one end side of the upper link 33 and lower link 34 (left side in the figure) is further swung downward about the fulcrum 29 and 31, shaft support portion swingably supported on the pivot 30, 32 28 also swings further downward. While maintaining the displacement of the secondary transfer roller shaft 14, the recording paper 19 passes through the nip between the secondary transfer roller 12 and the intermediate transfer belt 3, where secondary transfer to the recording paper 19 is performed. Further, as described above, the shaft support portion 28 further swings downward, so that the pressing spring 18a is compressed and its shape changes. The leading edge of the recording paper 19 reaches the axial center intersection 23 and then moves away from both the secondary transfer roller 12 and the intermediate transfer belt 3 through the post nip point 24.

In such a color printer 100 according to the sixth embodiment of the present invention, the shaft support portion 28 (corresponding to the shaft support member) has a nip range (pre-nip point) between the intermediate transfer belt 3 and the secondary transfer roller 12. 22, the axial center intersection 23, and the post nip point 24), the upstream link 33 is at the upstream end in the conveying direction at the fulcrum 30 (corresponding to the first one fulcrum) and at the fulcrum 32 (corresponding to the second one fulcrum). (Corresponding to the first link member) and the lower link 34 (corresponding to the second link member) are supported, and the other end downstream in the transport direction with respect to the nip range is intermediately transferred by the pressing spring 18a. The upper link 33 and the lower link 34 are urged toward the belt 3 and are supported by fulcrums 30 and 32 at one end of the shaft support portion 28, and upstream of the nip range in the transport direction and at the fulcrum 30. , Vs 32 The upper link 33 and the lower link 34 swing around the fulcrums 29 and 31 as the recording paper 19 enters the nip, and the shaft support portion 28 is supported by the fulcrums 29 and 31 provided upstream in the transport direction. By swinging independently of each other about the fulcrums 30 and 32, the first to third problems described above can be solved. This configuration corresponds to an embodiment of the present invention according to claims 2 and 7.

  Here, the bearing 15a does not slide according to the paper thickness, and the swinging motion of the upper link 33 and the lower link 34 around the fulcrums 29 and 31 provided on the main body side plate or the fulcrums 30 and 32 as the center. By replacing the pivoting motion of the shaft support portion 28, the influence of the wear of the sliding portion and the adhesion of foreign matters in the prior art is avoided to prevent deterioration over time, and the leading edge of the thick paper reaches the secondary transfer area. In this case, since the bearing 15a is quickly retracted along with the swinging operation, the speed unevenness in the transport direction (sub-scanning direction) can be reduced and the so-called jitter phenomenon can be prevented. Further, in order to supply a transfer bias current to the secondary transfer roller 12, an energization unit that enables energization to a conductive bearing transfer unit (for example, the secondary transfer roller 12 and the bearing 15a) using a conductive material. When it is provided, since there is no sliding wear, the occurrence of gap play and poor electrical conductivity due to the attachment of abrasion powder and foreign matter are reduced, and good image transfer can be performed continuously.

  Further, a four-link mechanism (so-called equal-length link) that is parallel to the conveyance surface of the recording paper 19 and is equal in length to the conveyance surface of the recording paper 19 upstream of the pre-nip point 22, the axis center intersection 23, and the post-nip point 24. Mechanism) and the fulcrums 29, 30, 31, and 32 are arranged on both the main body side plate and the upper link 33 and the lower link 34 having the same height as the rotation center of the secondary transfer roller 12. The rocking angle changes in accordance with the thickness, and the fluctuation range of the secondary transfer position in the sub-scanning direction accompanying this change can be reduced. In particular, the arrangement of the isometric link mechanism prevents the secondary transfer roller 12 from biting when the leading edge of the recording paper 19 reaches the nip. Reduction of the generated jitter and transfer failure due to the shift of the secondary transfer position can be avoided, and good image transfer can be performed without being affected by the paper thickness.

  In the above-described embodiment, a straight line that passes through the shaft centers of the registration roller pair 10 and a straight line that passes through the shaft center of the opposing roller 8 and the shaft center of the secondary transfer roller 12 (center of the secondary transfer roller shaft 14). However, in the present invention, in addition to this, the straight line passing through the axial centers of the registration roller pair 10, the axial center of the opposing roller 8, and the axial center of the secondary transfer roller 12 ( The same effect can be obtained even if the straight line passing through the center of the secondary transfer roller shaft 14 is not parallel. For example, even when the recording paper conveyance path 11 between the axis center intersection (not shown) of the registration roller pair 10 and the axis center intersection 23 of the opposing roller 8 and the secondary transfer roller 12 has a curved line. The invention can be applied.

  In this case, the shaft support portion 28 (corresponding to the shaft support member) faces the intermediate transfer belt 3 (corresponding to the image carrier), and the intermediate transfer belt 3 and the secondary transfer roller 12 (to the first rotating body). (Corresponding) at the axis center intersection 23 (corresponding to the nip point) of the counter roller 8 (corresponding to the second rotating member of the image carrier) and the center (first) of the secondary transfer roller shaft 14. A straight line (corresponding to a first straight line) passing through a straight line (corresponding to the rotational axis of the rotating body) upstream of the recording paper 19 in the transport direction (corresponding to a second straight line). It is arranged substantially in parallel and has a configuration for supporting the secondary transfer roller shaft 14.

  Further, the upper link 33 (corresponding to the first link member) is disposed substantially parallel to the second straight line, and is a fulcrum 30 (corresponding to the first one fulcrum) provided at one end of the shaft support portion 28. And is supported by a fulcrum 29 (corresponding to the first other fulcrum) provided upstream of the axis center intersection 23 and the fulcrum 30 in the conveyance direction of the recording paper 19. It has a configuration that works with Further, the lower link 34 (corresponding to the second link member) is disposed substantially parallel to the second straight line, and is a fulcrum 32 (corresponding to a second one fulcrum) provided at one end of the shaft support portion 28. And is supported by a fulcrum 31 (corresponding to the second other fulcrum) provided upstream of the axis center intersection 23 and the fulcrum 32 in the conveyance direction of the recording paper 19. It has a configuration that works with

  Here, the shaft support 28, the upper link 33, and the lower link 34 are the first straight line, a straight line passing through the fulcrum 30 and the fulcrum 32 (corresponding to the third straight line), and a straight line passing through the fulcrum 29 and the fulcrum 31. (Corresponding to the fourth straight line) are arranged so as to be substantially parallel to each other. The non-parallel configuration corresponds to an embodiment of the present invention according to claims 2 and 7.

[Seventh Embodiment]
Next, FIG. 13 shows a support structure in the secondary transfer portion of the color printer 100 according to the seventh embodiment of the present invention. This is different from the sixth embodiment in that a damper 27 and a damper contact portion 26 are provided on the downstream side in the transport direction of the shaft support portion 28. The parts excluding the damper 27 and the damper contact portion 26 as the vibration damping means are the same as those in the sixth embodiment. Therefore, FIG. 1 is used, the same reference numerals are given to the same components, and the description is partially omitted. .

  In FIG. 13A, a damper 27 is provided downstream in the transport direction (downstream in the transport direction of the main body side leaf spring receiving portion 16a) with respect to the above-described axis center intersection 23, and the other end of the shaft support portion 28 (the left end in the figure). ) Is formed with a damper contact portion 26. The damper contact portion 26 can swing in the vertical direction together with the secondary transfer roller shaft 14 as the upper link 33, the lower link 34 and the shaft support portion 28 swing around the fulcrums 29, 30, 31, 32. It has become. When the secondary transfer is not performed, the damper contact portion 26 is in contact with the damper 27 that is not deformed. The shaft support portion 28 corresponds to a part of the arm (for example, 21 in FIG. 11).

  With respect to the secondary transfer operation of the color printer 100 configured as described above, the displacement of the contact point between the intermediate transfer belt 3 and the secondary transfer roller 12 will be described with reference to FIG. Here, with the movement of the recording paper 19 to the secondary transfer position, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3 in the order of FIG. 13A and FIG. . FIG. 13A shows an initial state.

  In FIG. 13A, the recording paper 19 is conveyed from the registration roller pair 10 to the secondary transfer position. Here, the leading edge of the recording paper 19 first comes into contact with the secondary transfer roller 12 at the initial contact point 25 (not shown), but is not in contact with the intermediate transfer belt 3, so the impact on the intermediate transfer belt 3 is Does not occur. Further, as described above, the damper 27 is in contact with the damper contact portion 26 but is not deformed.

Although not shown in detail, thereafter, the leading edge of the recording paper 19 is further conveyed from the initial contact point 25 and reaches the pre-nip point 22 upstream of the axial center intersection 23 in the conveying direction. After reaching the pre-nip point 22 in this way, the leading edge of the recording paper 19 further enters between the secondary transfer roller 12 and the intermediate transfer belt 3. Here, since the secondary transfer roller shaft 14 is supported by the bearing 15 a of the swingable shaft support portion 28, the upper link 33 and the lower link 34 swing as the prenip point 22 enters. Thus, the secondary transfer roller 12 is also displaced downward. That is, the upper link 33 and (in the figure, left) one end side of the lower link 34 swings downward about the fulcrum 29 and 31, the shaft support portion 28 which is swingably supported on the pivot 30, 32 Swings downward. Due to the displacement of the secondary transfer roller shaft 14, a gap (gap) is generated between the secondary transfer roller 12 and the intermediate transfer belt 3, and the impact (rotational load, speed fluctuation) on the intermediate transfer belt 3 is reduced. . Further, since the link fulcrums 29, 30, 31, 32 are located upstream of the pre-nip point 22 in the conveyance direction of the recording paper 19, they do not become so-called bite (learning) and reduce the impact on the intermediate transfer belt 3. Will do. Further, as described above, the shaft support portion 28 swings downward, so that the damper contact portion 26 pushes down the damper 27 and the damper 27 is deformed. That is, the shape is swollen in the width direction as the height dimension is shortened. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14.

Further, in FIG. 13B, the leading edge of the recording paper 19 is further conveyed from the pre-nip point 22 and reaches the above-described axial center intersection 23. Here, as the shaft center intersects with the shaft 23, the shaft support 28 swings further downward as compared with the approach to the prenip point 22 (not shown), whereby the shaft of the secondary transfer roller shaft 14 is moved. The center is also displaced downward (the position of the lower dotted line on the secondary transfer roller shaft 14 in FIG. 13B). Further, the locus of the contact point between the secondary transfer roller 12 and the intermediate transfer belt 3 is also displaced. Ie one end side of the upper link 33 and lower link 34 (left side in the figure) is further swung downward about the fulcrum 29 and 31, in accordance with this swinging, the other end of the pivot 30, The shaft support portion 28 supported so as to be swingable by the shaft 32 is further swung downward. While maintaining the displacement of the secondary transfer roller shaft 14, the recording paper 19 passes through the nip between the secondary transfer roller 12 and the intermediate transfer belt 3, where secondary transfer to the recording paper 19 is performed. Further, as described above, the shaft support portion 28 further swings downward, so that the pressing spring 18a is compressed and its shape changes. Further, as described above, the shaft support portion 28 swings further downward, so that the damper contact portion 26 further pushes down the damper 27, and the shape changes like the damper 27b. That is, the shape is swollen in the width direction as the height dimension is further shortened. The depression by the damper contact portion 26 corresponds to the displacement of the axial center height of the secondary transfer roller shaft 14. The leading edge of the recording paper 19 reaches the axial center intersection 23 and then moves away from both the secondary transfer roller 12 and the intermediate transfer belt 3 through the post nip point 24.

  According to such a color printer 100 according to the seventh embodiment of the present invention, the vibration of the secondary transfer roller shaft 14 caused by the swing of the arm 21 downstream of the secondary transfer roller 12 in the transport direction. By providing a damper 27 (corresponding to a vibration damping means) that attenuates the vibration, the vibration shock of the secondary transfer roller 12 due to the nip of the recording paper 19 can be attenuated. This configuration corresponds to an embodiment of the present invention according to claim 8.

  In the above-described embodiment, the case where one damper 27 that contacts the damper contact portion 26 in the initial state is used as the vibration attenuating means has been described. However, the present invention is not limited to this. The same effect can be obtained by applying the fifth embodiment. In this case, the vibration damping means includes a damper (corresponding to 272 in FIG. 8) that attenuates the amplitude of vibration of the secondary transfer roller shaft 14 by elastically deforming in contact with the shaft support portion 28. In accordance with the increase, the elastic deformation amount of the damper is continuously increased. This configuration corresponds to an embodiment of the present invention according to claim 9. Alternatively, as the vibration attenuating means, a plurality of dampers (corresponding to 273, 274, and 275 in FIG. 5) that attenuate the amplitude of vibration of the secondary transfer roller shaft 14 by elastically deforming in contact with the shaft support portion 28 are provided. In addition, the elastic deformation amount of each damper changes according to the increase in the amplitude. This configuration corresponds to an embodiment of the present invention according to claim 10.

  In the first to seventh embodiments described above, the case where the intermediate transfer belt 3 stretched over the belt driving roller 6, the belt driven roller 7, and the opposing roller 8 is used as the image carrier is described. In the present invention, the same effect can be obtained by using an intermediate transfer roller (rotating body).

1 is a cross-sectional view illustrating an outline of a color printer according to a first embodiment of the present invention. FIG. 6 is a cross-sectional view (part 1) illustrating the support structure of the secondary transfer unit and the secondary transfer operation according to the first embodiment of the present invention. FIG. 6 is a sectional view (No. 2) showing the support structure of the secondary transfer portion and the secondary transfer operation according to the first embodiment of the present invention. FIG. 9 is a cross-sectional view (part 1) illustrating a support structure of a secondary transfer portion and a secondary transfer operation according to a second embodiment of the present invention. It is sectional drawing (the 2) which shows the support structure and secondary transfer operation | movement of a secondary transfer part which concern on the 2nd Embodiment of this invention. It is sectional drawing (the 1) which shows the support structure and secondary transfer operation | movement of a secondary transfer part which concern on the 3rd Embodiment of this invention. It is sectional drawing (the 2) which shows the support structure and secondary transfer operation | movement of a secondary transfer part which concern on the 3rd Embodiment of this invention. It is sectional drawing (the 1) which shows the support structure and secondary transfer operation | movement of a secondary transfer part which concern on the 4th Embodiment of this invention. It is sectional drawing (the 2) which shows the support structure and secondary transfer operation | movement of a secondary transfer part which concern on the 4th Embodiment of this invention. It is sectional drawing (the 1) which shows the support structure and secondary transfer operation | movement of a secondary transfer part which concern on the 5th Embodiment of this invention. It is sectional drawing (the 2) which shows the support structure and secondary transfer operation | movement of a secondary transfer part which concern on the 5th Embodiment of this invention. It is sectional drawing which shows the support structure and secondary transfer operation | movement of the secondary transfer part which concern on the 6th Embodiment of this invention. It is sectional drawing which shows the support structure and secondary transfer operation | movement of the secondary transfer part which concern on the 7th Embodiment of this invention. FIG. 10 is a cross-sectional view illustrating a support structure of a secondary transfer unit according to a conventional image forming apparatus.

Explanation of symbols

1Y, 1M, 1C, 1Bk Image forming unit 2Y, 2M, 2C, 2Bk Primary transfer unit 3 Intermediate transfer belt 4 Belt drive motor 5 Belt drive gear 6 Belt drive roller 7 Belt driven roller 8 Opposed roller 9 Belt stretching roller 10 Registration roller pair 11 recording paper conveyance path (conveyance path of recording paper 19)
12 Secondary transfer roller 13 Fixing roller pair 14 Secondary transfer roller shaft 15 Slide bearing 15a Bearing 16 Main body side plate 16a Main body side leaf spring receiving portion 17 Notch portions 18, 18a Pressing spring 19 Recording paper 20 Arm rotation fulcrum 21 Arm 22 Prenip point 23 Axis center intersection 24 Post nip point 25 Initial contact point 26 Damper contact portion 27 Damper 28 Shaft support portions 29, 30, 31, 32 Support point 33 Upper link 34 Lower link

Claims (10)

A first rotating body, a second rotating body facing the first rotating body, an image carrier that is sandwiched between the first rotating body and the second rotating body and carries a visible image The first rotating body and the image carrier rotate while sandwiching a predetermined recording paper, and the visible image carried on the image carrier is transferred while transporting the recording paper. A recording paper transport mechanism for transferring to a recording paper,
The image bearing member supports a rotation axis of the first rotating body, is substantially orthogonal to a first straight line passing through the rotation axis of the second rotating body and the rotation axis of the first rotating body, and An arm member that swings around a fulcrum provided upstream in the conveyance direction of the recording paper from the nip point on a second straight line passing through the nip point between the body and the first rotating body, and the arm member Biasing means for biasing toward the image carrier,
Due to the urging force of the urging means, the first rotating body presses the image carrier, and the arm member swings around the fulcrum as the recording paper enters the nip point. A recording paper transport mechanism characterized by the above. A first rotating body, a second rotating body facing the first rotating body, an image carrier that is sandwiched between the first rotating body and the second rotating body and carries a visible image And a main body that rotatably supports the first rotating body, the second rotating body, and the image carrier, and the first rotating body and the image carrier are a predetermined recording sheet. A recording paper transport mechanism for transferring the visible image carried on the image carrier to the recording paper while transporting the recording paper.
The image carrier and the first rotation are substantially orthogonal to a first straight line facing the image carrier and passing through the rotation axis of the second rotator and the rotation axis of the first rotator. A shaft support member that is disposed substantially parallel to a second straight line that passes through a nip point with the body and supports the rotation shaft of the first rotating body;
The first end fulcrum provided at one end of the shaft support member is supported so as to be swingable with respect to the shaft support member, and is disposed substantially parallel to the second straight line. A first link member that is supported so as to be swingable with respect to the main body at a first other end fulcrum provided upstream in the conveyance direction of the recording paper with respect to both one end fulcrum, and interlocks with the shaft support member When,
The second straight line is disposed substantially parallel to the second straight line, and is supported so as to be swingable with respect to the shaft support member at a second end fulcrum provided at one end of the shaft support member. A second link member that is swingably supported with respect to the main body at a second other end fulcrum provided upstream of the one end fulcrum of the recording paper in the conveying direction of the recording paper and interlocks with the shaft support member. When,
Urging means for urging the shaft support member toward the image carrier,
The first straight line, the third straight line passing through the first one end fulcrum and the second one end fulcrum, and the fourth straight line passing through the first other end fulcrum and the second other end fulcrum are mutually. To be almost parallel,
The shaft support member, the first link member, the second link member, and the main body constitute a parallel link mechanism having the main body as a fixed link,
By the urging of the urging means, the first rotating body presses the image carrier,
In response to the recording paper entering the nip point, the first rotating body displaces the shaft support member against the urging force of the urging means, and the displacement of the shaft support member causes the first rotation member to move. One link member swings about the first other end fulcrum, and the second link member swings about the second other end fulcrum. mechanism. The recording paper transport mechanism according to claim 1 is provided.
The image carrier and the first rotator rotate while sandwiching a predetermined recording paper, and transfer the visible image formed on the image carrier to the recording paper while conveying the recording paper, an image forming apparatus comprising a Turkey to form an image on paper the recording. The image forming apparatus according to claim 3.
An image forming apparatus comprising: a vibration attenuating means for attenuating vibration of the rotation shaft of the first rotating body caused by the swing of the arm member according to claim 1. The image forming apparatus according to claim 4.
The vibration damping means includes a damper that attenuates the amplitude of vibration of the rotation shaft of the first rotating body by elastically deforming in contact with the arm member, and elastically deforming the damper according to an increase in the amplitude. An image forming apparatus characterized in that the amount is continuously increased. The image forming apparatus according to claim 4.
The vibration attenuating means has a plurality of dampers for attenuating the amplitude of vibration of the rotating shaft of the first rotating body by elastic deformation in contact with the arm member, and the elasticity of each damper according to the increase in the amplitude. An image forming apparatus characterized in that a deformation amount is changed. A recording paper transport mechanism according to claim 2 is provided.
The image carrier and the first rotator rotate while sandwiching a predetermined recording paper, and transfer the visible image formed on the image carrier to the recording paper while conveying the recording paper, an image forming apparatus comprising a Turkey to form an image on paper the recording. The image forming apparatus according to claim 7.
An image forming apparatus, comprising: a vibration attenuating means for attenuating vibration of the rotating shaft of the first rotating body caused by swinging of the shaft support member according to claim 2. The image forming apparatus according to claim 8.
The vibration damping means has a damper that attenuates the amplitude of vibration of the rotation shaft of the first rotating body by being elastically deformed in contact with the shaft support member, and the elasticity of the damper according to the increase in the amplitude. An image forming apparatus characterized in that the amount of deformation increases continuously. The image forming apparatus according to claim 8.
The vibration attenuating means has a plurality of dampers for attenuating the amplitude of vibration of the rotating shaft of the first rotating body by elastically deforming in contact with the shaft support member, and for each damper as the amplitude increases. An image forming apparatus characterized in that the amount of elastic deformation changes.

Images