JP2014034437A - Transport device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transport device which reduces harsh noise generated when a rear end of a recording media passes through a tip position of a sheet-like member arranged so as to protrude from a tip of a guide member, and to provide an image forming apparatus.SOLUTION: A sheet-like member 31 arranged so as to protrude from a tip of the guide member 32 is rotated by rotating means 33-37 so that a tip 31a of the sheet-like member 31 is inclined in a width direction of a recording media P at the latest by the time when a rear end Pb of the recording media P reaches the tip 31a of the sheet-like member 31.

Description

  The present invention relates to a conveyance device that conveys a recording medium, and an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine including the same.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a guide member (conveyance guide plate) that guides a recording medium to be conveyed in a predetermined direction along a conveyance path protrudes downstream in the conveyance direction from the leading end portion thereof. Thus, the technique which sticks flexible sheet-like members, such as Mylar, is known (for example, refer patent documents 1 and 2).

  In such an image forming apparatus, the recording medium that has passed through the tip of a rigid guide member such as a metal plate is conveyed downstream in the conveying direction while being guided along a flexible sheet-like member. As a result, the recording medium can be smoothly conveyed toward the downstream side of the guide member in the conveyance direction.

  In the conventional image forming apparatus described above, an irritating sound is generated when the rear end of the recording medium passes through the front end position of the sheet-like member.

  The present invention has been made to solve the above-described problems, and when the trailing end of a recording medium passes through the leading end position of a sheet-like member installed so as to protrude from the leading end portion of the guide member. An object of the present invention is to provide a transport device and an image forming apparatus in which unpleasant sound generated is reduced.

  The inventor of the present application has conducted research to solve the above problems, and as a result, the tip of the sheet-like member installed so as to protrude from the tip of the guide member is inclined with respect to the width direction of the recording medium. The inventors have come to know that it is possible to reduce the harsh sound that occurs when the rear end of the recording medium passes through the front end position of the sheet-like member.

  The present invention is based on the above-described matters. That is, the transport device according to the first aspect of the present invention is a transport device for transporting a recording medium, and the recording medium is transported in a predetermined direction. And a guide member provided with a sheet-like member installed so as to protrude from the front end located on the downstream side in the conveyance direction of the recording medium, and the sheet-like member with respect to the conveyance surface of the sheet-like member A rotating means for rotating the recording medium in parallel, and the rotating means includes at least a time when the rear end of the recording medium reaches the leading end position of the protruding portion of the sheet-like member protruding from the leading end portion. The sheet-like member is rotated so that the front end is inclined at a predetermined inclination angle with respect to the width direction.

  In the present invention, the sheet-like member installed so as to protrude from the front end portion of the guide member protrudes with respect to the width direction of the recording medium at least when the rear end of the recording medium reaches the front end position of the sheet-like member. Since the rotating means is rotated so that the front end of the part is inclined, the harsh sound generated when the rear end of the recording medium passes through the front end position of the sheet-like member is reduced, and the conveying device and the image A forming apparatus can be provided.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram illustrating a conveyance device installed in the image forming apparatus of FIG. 1. It is a top view which shows a part of conveying apparatus of FIG. It is a figure which shows operation | movement of a conveying apparatus. It is a figure which shows the state in which a recording medium is conveyed. It is a graph which shows the grade of the sound produced in the vicinity of the conventional conveying apparatus. It is a graph which shows the grade of the sound produced in the vicinity of a conveying apparatus when changing the inclination | tilt angle (alpha) of a sheet-like member. It is a graph which shows the grade of the sound which arises in the vicinity of a conveyance apparatus when a recording medium with small basis weight is passed. It is a graph which shows the example of the sound data collected with the microphone.

Embodiment.
Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes an apparatus main body of a copying machine as an image forming apparatus, 2 an original reading unit that optically reads image information of an original D, and 3 an exposure light L based on image information read by the original reading unit 2. Is exposed to the photosensitive drum 5, 4 is an image forming unit for forming a toner image (image) on the photosensitive drum 5, and 7 is a toner image formed on the photosensitive drum 5 on the recording medium P. A transfer unit (image forming unit) to be transferred, 10 is a document conveying unit that conveys a set document D to the document reading unit 2, and 12 to 14 are sheet feeding units (sheet feeding) in which a recording medium P such as transfer paper is stored. (Cassettes), 17 and 18 are registration rollers (timing rollers) for conveying the recording medium P toward the transfer unit 7, 20 is a fixing device for fixing an unfixed image on the recording medium P, and 21 is installed in the fixing device 20. The fixing roller 22 is installed in the fixing device 20. The pressure roller, 25 denotes a manual paper feed unit, for feeding to set the recording medium P manually.

With reference to FIG. 1, an operation during normal image formation in the image forming apparatus will be described.
First, the document D is conveyed from the document table in the direction of the arrow in the drawing by the conveyance roller of the document conveyance unit 10 and passes over the document reading unit 2. At this time, the document reading unit 2 optically reads the image information of the document D passing above.
Then, the optical image information read by the document reading unit 2 is converted into an electric signal and then transmitted to the exposure unit 3 (writing unit). Then, exposure light L such as laser light based on the image information of the electrical signal is emitted from the exposure unit 3 toward the photosensitive drum 5 of the image forming unit 4.

On the other hand, in the image forming unit 4, the photosensitive drum 5 is rotated in the clockwise direction in the drawing, and image information is transferred onto the photosensitive drum 5 through a predetermined image forming process (charging process, exposure process, development process). An image (toner image) corresponding to is formed.
Thereafter, the image formed on the photosensitive drum 5 is transferred onto the recording medium P conveyed by the registration rollers 17 and 18 in the transfer unit 7 as an image forming unit.

On the other hand, the recording medium P conveyed to the transfer unit 7 (image forming unit) operates as follows.
First, a plurality of paper feeding units 12 to 14 (paper feeding cassettes) disposed below the image forming apparatus main body 1 and a manual paper feeding unit 25 disposed on the side of the image forming apparatus main body 1 are provided. One of the paper feeding units is automatically or manually selected (for example, it is assumed that the lowermost paper feeding unit 14 is selected).
Then, the uppermost sheet of the recording medium P stored in the paper feeding unit 14 is transported toward the position of the transport path K.

Thereafter, the recording medium P passes through a conveyance path K in which a plurality of conveyance rollers are arranged, and further passes through a junction X with the conveyance path from the manual sheet feeding unit 25, so that the registration rollers 17 and 18. Reach position. Then, the recording medium P that has reached the positions of the registration rollers 17 and 18 is directed to the transfer unit 7 (image forming unit) at the same timing in order to align with the image formed on the photosensitive drum 5. Be transported.
Even when the manual sheet feeding unit 25 is selected, the recording medium P passes from the manual sheet feeding unit 25 through a linear conveyance path (straight conveyance path) in which the conveyance rollers 26 and 27 are disposed. Further, the toner passes through the junction X and is conveyed from the position of the registration rollers 17 and 18 toward the transfer unit 7 (image forming unit).

After the transfer process, the recording medium P passes through the position of the transfer unit 7 and then reaches the fixing device 20 through the conveyance path. The recording medium P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22. The The recording medium P on which the image has been fixed is delivered from between the fixing roller 21 and the pressure roller 22 (a nip portion) and then discharged from the image forming apparatus main body 1.
Thus, a series of image forming processes is completed.

Next, with reference to FIG. 2 and FIG. 3, the transport device 30 that is characteristic in the present embodiment will be described in detail.
FIG. 2 is a configuration diagram illustrating the transport device 30. 3 is a top view showing the vicinity of the upper guide plate 32 in the transport device 30 (a top view seen from a direction orthogonal to the surface of the recording medium P).

With reference to FIGS. 2 and 3, the conveyance device 30 includes conveyance rollers 15 and 16, a lower guide plate 19, and a guide as a guide member along the conveyance path of the recording medium P from the paper feeding units 12 to 14. A plate 32 (holding plate), registration rollers 17 and 18 (timing rollers), and the like are provided. Further, along the conveyance path of the recording medium P from the manual sheet feeding unit 25, conveyance rollers 26 and 27, a guide plate 29, a sheet-like member 31 (guide member 32), registration rollers 17 and 18, and the like are arranged. ing. Note that the conveyance path (curved conveyance path) from the sheet feeding units 12 to 14 and the conveyance path (straight line conveyance path) from the manual sheet feeding unit 25 are merged portions X at positions upstream of the registration rollers 17 and 18. (See FIG. 1).
The recording medium P is conveyed by the conveying device 30 toward the transfer unit 7 (the position where the photosensitive drum 5 and the transfer roller are opposed to each other) as an image forming unit that forms an image on the recording medium P. become.

Specifically, the recording medium P that has reached the position of the transport rollers 15 and 16 via the transport path from the paper feeding units 12 to 14 is a guide plate 32 (guide member) on which the sheet-like member 31 is installed, or the lower guide plate 19. Are conveyed to the positions of the registration rollers 17 and 18. The recording medium P that has reached the position of the transport rollers 26 and 27 via the transport path from the manual sheet feeding unit 25 is guided to the guide plate 29 and the sheet-like member 31 installed on the guide plate 32 (guide member). However, it is conveyed to the position of the registration rollers 17 and 18.
The recording medium P conveyed to the position of the registration rollers 17 and 18 has its leading end abutted against the registration rollers 17 and 18 whose rotation drive has been stopped, thereby correcting skew (skew correction) and vertical registration correction (conveyance). Then, the image is conveyed toward the transfer unit 7 (image forming unit) in time with the image on the photosensitive drum 5. Thus, a desired image is transferred onto the recording medium P.

  More specifically, the registration rollers 17 and 18 are a pair of rollers disposed on the downstream side in the conveyance direction of the recording medium P with respect to the transfer unit 7 (image forming unit). The registration rollers 17 and 18 are configured to be rotationally driven and stopped independently of the conveying rollers 15 and 16 (26 and 27) by a motor (not shown). Then, by the on / off operation of the motor, as described above, after the leading end of the recording medium P hits the registration rollers 17 and 18 in a state where the rotational driving is stopped and the skew correction / longitudinal registration correction is performed, a predetermined value is obtained. The recording medium P is conveyed toward the transfer unit 7 (image forming unit) by the registration rollers 17 and 18 that have started to rotate at the timing.

Here, referring to FIG. 2, in conveying device 30 in the present embodiment, guide plate 32 (upper guide plate) as a guide member is made of a rigid material such as stainless steel having a plate thickness of about 1 to 2 mm. It is a sheet metal and is disposed so as to face the convex surface side of the recording medium P that is curved in the conveyance path along which the recording medium P is conveyed while being curved.
Then, on the upper guide plate 32 (guide member), a sheet-like member 31 (flexible member) is projected so as to protrude from the front end located on the downstream side (the downstream side in the conveyance direction of the recording medium P). is set up. The sheet-like member 31 is a film-like member made of a flexible material such as PET (polyethylene terephthalate) or polyester having a thickness of about 0.1 to 0.3 mm, and is downstream from the tip portion of the upper guide plate 32. It is stuck on the conveying surface (the surface facing the recording medium P) of the upper guide plate 32 so as to protrude in the range of several mm to several tens mm on the side.
Further, the guide plate 32 (upper guide plate) as a guide member has a protruding portion (tip 31a) of the sheet-like member 31 having two conveyance paths (a conveyance path from the sheet feeding units 12 to 14 and a manual sheet feeding unit). , And a conveying path from 25.) are arranged so as to protrude toward the merging portion X where they merge.

In this way, by installing the flexible sheet-like member 32 so as to protrude from the front end portion of the guide plate 32 (guide member), the recording medium is directed toward the nip portion of the registration rollers 17 and 18 (timing roller). P can be guided smoothly. In other words, the sheet-like member 32 is flexible, and even if the sheet-like member 32 comes into contact with the registration rollers 17 and 18, it is difficult for both members to be damaged. Can be installed.
Further, it protrudes toward the junction X (also see FIG. 1) of the conveyance path from the sheet feeding units 12 to 14 (sheet feeding cassette) and the conveyance path from the manual sheet feeding unit 25. Since the sheet-like member 31 is provided, the recording medium P conveyed through the conveyance path from the manual sheet feeding unit 25 is also guided to the sheet-like member 32 and is placed in the nip portion of the registration rollers 17 and 18. It will be smoothly transported towards.
Further, since the sheet-like member 31 is installed so as to protrude toward the joining portion X, the recording medium P conveyed from the conveyance path from the sheet feeding units 12 to 14 is conveyed from the manual sheet feeding unit 25. The recording medium P conveyed from the conveyance path from the manual sheet feeding unit 25 without interfering with the conveyance path of the recording medium P in the junction X without interfering with the conveyance path from the sheet feeding units 12 to 14. A decrease can be prevented.

  In the present embodiment, the sheet-like member 31 projects from the rear end portion (the end portion on the upstream side in the transport direction) of the upper guide plate 32 to the upstream side within a range of several mm to several tens mm. Is formed. As a result, the impact when the trailing edge of the recording medium P conveyed from the paper feeding units 12 to 14 is separated from the guide plate extending in the vertical direction and collides with the upper guide plate 32 is reduced.

Here, the conveying device 30 in the present embodiment is a rotating means 33 that rotates the sheet-like member 31 substantially parallel to the conveying surface of the sheet-like member 31 (the surface facing the recording medium P). -37 are installed.
Then, the rotation of the sheet-like member 31 (projecting portion) by the rotation means 33 to 37 until the rear end Pb of the recording medium P reaches at least the position (tip position) of the leading end 31a of the projecting portion of the sheet-like member 31. The sheet-like member 31 rotates so that the front end 31a is inclined at a predetermined inclination angle α with respect to the width direction (the direction perpendicular to the conveyance direction of the recording medium P and the direction perpendicular to the paper surface in FIG. 2). It is moved (turned to the state of FIG. 4B).
Specifically, the rotation of the sheet-like member 31 (projecting portion) by the rotating means 33 to 37 until the tip Pa of the recording medium P reaches at least the position (tip position) of the leading end 31a of the projecting portion of the sheet-like member 31. The sheet-like member 31 is rotated so that the tip 31a is substantially parallel to the width direction (the state shown in FIG. 3). Then, immediately before the rear end Pb of the recording medium P reaches the position (front end position) of the leading end 31a of the protruding portion of the sheet-like member 31 by the rotating means 33 to 37, the leading end 31a of the sheet-like member 31 (protruding portion). Is rotated at a predetermined inclination angle α with respect to the width direction (changes from the state of FIG. 4A to the state of FIG. 4B).
In the present embodiment, the sheet-like member 31 is rotated by the rotating means 33 to 37 immediately after the rear end Pb of the recording medium P passes the position (tip position) of the leading end 31a of the protruding portion of the sheet-like member 31. The sheet-like member 31 is rotated so that the tip 31a of the (projection) is substantially parallel to the width direction (changes from the state of FIG. 4B to the state of FIG. 3).

More specifically, referring to FIG. 2 and FIG. 3, the rotating means for rotating the sheet-like member 31 is fixed so as to stand on the non-conveying surface of the guide plate 32 and is mounted on the apparatus main body 1. A rotation shaft 33 rotatably held via a pulley, a pulley 34 (timing pulley) fixed on the rotation shaft 33, and a stepping motor 37 held by the apparatus main body 1 (formed to be rotatable in both forward and reverse directions). A stepping motor), a pulley 35 (timing pulley) fixed to the motor shaft of the stepping motor 37, a timing belt 36 stretched around and meshed with the two pulleys 34, 35, and the like.
On the other hand, as shown in FIG. 3, the sheet-like member 31 is guided so that the protruding portion protrudes in parallel with the leading end portion of the guide plate 32 (or the leading end portion Pa and the trailing end portion Pb of the recording medium P). The plate 32 is fixed (attached). With such a configuration, when the stepping motor 37 is operated, the rotational driving force is transmitted to the shaft portion 33 via the timing belt 36, and the sheet-like member 31 is rotated together with the guide plate 32. .

  Here, the rotation angle (inclination angle α) of the sheet-like member 31 is varied to a target value by the stepping motor 37 controlled by the control unit 46. In addition, the timing at which the sheet-like member 31 is rotated is the paper detection sensor 41 (photo sensor) installed downstream of the conveyance rollers 26 and 27 and upstream of the sheet-like member 31 (tip 31a) in the conveyance path. This is performed based on the detection of the leading edge Pa of the recording medium P detected by.

Specifically, in the present embodiment, as shown in FIG. 3, the inclination angle α of the sheet-like member 31 is 0 before the leading end Pa of the recording medium P reaches the position of the sheet-like member 31 (guide plate 32). The rotation means 33 to 37 are controlled by the control unit 46 so as to be at a certain degree (so that the front end 31a of the sheet-like member 31 is parallel to the front end Pa and the rear end Pb of the recording medium P).
Then, the inclination angle α (0 degree) of the sheet-like member 31 is, as shown in FIG. 4A, after the leading end Pa of the recording medium P reaches the position of the sheet-like member 31 (guide plate 32). The rear end Pb is maintained until just before reaching the front end 31a of the sheet-like member 31.
Thereafter, as shown in FIG. 4B, immediately before the trailing end Pb of the recording medium P reaches the leading end 31a (tip position) of the sheet-like member 31, the inclination angle α of the sheet-like member 31 is 0.4 degrees or more. The rotation means 33 to 37 are controlled by the control unit 46 so that the predetermined value becomes 1.1 degrees or less (the sheet-like member 31 and the guide plate 32 are counterclockwise in FIG. 4B). To be rotated). Note that the position of the trailing edge Pb of the recording medium P described above is based on the time when the leading edge Pa of the recording medium P is detected by the paper detection sensor 41 (photo sensor), the size in the transport direction of the recording medium P, and the paper detection. Control is performed in consideration of the transport distance from the sensor 41, the transport speed of the recording medium P, the response time from when the stepping motor 37 receives a control command until the driving is started, the rotation angle and rotational speed of the stepping motor 37, and the like. This is required by the part 46.
Thereafter, immediately after the trailing edge Pb of the recording medium P passes through the leading edge 31a of the sheet-like member 31, the sheet-like member 31 has an inclination angle α of 0 degree (the sheet with respect to the trailing edge Pb of the recording medium P). The rotation means 33 to 37 are controlled by the control unit 46 (the sheet-like member 31 and the guide plate 32 are rotated clockwise in FIGS. 3 and 4) so that the tip 31a of the sheet-like member 31 is parallel. )

  In the present embodiment, the inclination angle α of the sheet-like member 31 when the rear end Pb of the recording medium P passes the leading end 31a of the sheet-like member 31 is 0.4 degrees or more and 1.1 degrees. It is set to be as follows (0.4 degrees ≦ α ≦ 1.1 degrees). FIG. 4B shows the inclination angle α larger than the actual angle in order to facilitate understanding of the configuration. Further, the front end portion and the rear end portion of the guide plate 32 are formed so as to be parallel to the front end Pa and the rear end Pb of the recording medium P (formed in parallel to the width direction). .

  Thus, in the present embodiment, when the trailing end Pb of the recording medium P passes through the leading end 31a of the sheet-like member 31, the leading end 31a of the sheet-like member 31 has an inclination angle of 0.4 degrees to 1.1 degrees. Since the sheet-like member 31 is rotated so as to be inclined at α, the rear end Pb of the recording medium P is the front end of the sheet-like member 31 as will be described in detail later with reference to FIGS. The peak sound S2 generated when passing through 31a can be reduced. Further, when the abdomen (surface) of the recording medium P passes through the tip 31a of the sheet-like member 31, the sheet-like member 31 is rotated so that the inclination angle α of the tip 31a of the sheet-like member 31 becomes 0 degree. Therefore, as will be described in detail later, the peak sound generated when the abdomen of the recording medium P is in sliding contact with the tip 31a of the sheet-like member 31 can be reduced.

  Here, in the present embodiment, the upper limit value of the inclination angle α of the sheet-like member 31 in the state of FIG. As will be described later with reference to FIGS. 5 to 7 and the like, the inclination angle is used to reduce the peak sound S2 generated when the rear end Pb of the recording medium P passes the front end 31a of the sheet-like member 31. It is sufficient to set α to 0.4 or more. If the inclination angle α is set to be larger than 1.1 degrees, it takes time to change the inclination angle α of the sheet-like member 31, or the sheet-like shape is increased. This is because a large space for moving the member 31 must be secured.

5-7 is a figure which shows the conditions and result of the experiment conducted in order to confirm the effect in this Embodiment mentioned above.
5A to 5C are diagrams illustrating a state in which the recording medium P fed from the manual sheet feeding unit 25 is conveyed while being guided by the sheet-like member 31. FIG. FIG. 6 is a graph showing the degree of sound generated in the vicinity of the conventional conveyance device 30 and is measured by the microphone 100 installed at the position (M = 30 cm, N = 20 cm) in FIG. This indicates the sound pressure level that has been set. 7A and 7B show the conveyance device 30 when the inclination angle α of the sheet-like member 31 is changed immediately before the trailing end Pb of the recording medium P passes the leading end 31a of the sheet-like member 31. 5 is a graph showing the degree of sound generated in the vicinity of, and shows the sound pressure level measured by the microphone 100 installed at the position (M = 30 cm, N = 20 cm) in FIG. is there. 6 and 7 are both performed on the image forming apparatus 1 using the recording medium P having a basis weight of 360 g / m ² and the conveyance speed of the recording medium P being set to 500 mm / second. It is a thing.

As shown in FIG. 6, when the recording medium P fed from the manual paper feed unit 25 passes through the transport device 30 in the order shown in FIGS. Sounds S1 and S2 are generated.
Specifically, as shown in FIG. 5B, the first peak sound S1 is generated by the registration rollers 17 and 18 after the leading edge Pa of the recording medium P reaches the position of the registration rollers 17 and 18 in the drive stop state. It occurs when driven. The second peak sound S2 is generated when the rear end Pb of the recording medium P passes through the front end 31a of the sheet-like member 31 as shown in FIG.
As shown in FIG. 6, in the conventional transport apparatus, when the rear end Pa of the recording medium P passes through the front end 31a of the sheet-like member 31, a peak sound S2 of about 78 dB that cannot be ignored is generated.

On the other hand, as shown in FIG. 7A, the trailing end Pb of the recording medium P is inclined to the sheet-like member 31 by inclining the leading end 31a of the sheet-like member 31 at an inclination angle α of 0.4 degrees. It can be seen that the peak sound S2 generated when passing through the tip 31a of the horn is as small as 73 db. Further, as shown in FIG. 7B, the rear end Pb of the recording medium P is inclined to the front end 31a of the sheet-like member 31 by inclining the front end 31a of the sheet-like member 31 at an inclination angle α of 1.1 degrees. It can be seen that the peak sound S2 generated when passing through is reduced to about 71 db.
In particular, it can be seen that the peak sound S2 gradually decreases as the inclination angle α of the leading end 31a of the sheet-like member 31 is set to be as large as 0.4 degrees and 1.1 degrees. This is considered to be because the timing at which the trailing end Pb of the recording medium P passes through the leading end 31a of the sheet-like member 31 is dispersed in the time axis direction as the inclination angle α of the leading end 31a of the sheet-like member 31 increases. . That is, the timing at which the rear end Pb of the recording medium P on one end side in the width direction passes through the front end 31a of the sheet-like member 31 and the rear end Pb of the recording medium P on the other end side in the width direction. It is considered that the peak sound P2 spreads in the time axis direction and becomes smaller because the timing of passing is shifted.

On the other hand, when the inclination angle α of the tip 31a of the sheet-like member 31 was fixed to 0 degree, 0.4 degree, and 1.1 degree, respectively, and experiments similar to those of FIGS. As α is set larger, the sliding sound (sheet edge sliding) that occurs when the abdomen of the recording medium P (the surface portion between the leading end Pa and the trailing end Pb) is in sliding contact with the leading end 31a of the sheet-like member 31. It was found that the (close sound) increased.
Specifically, when the abdomen (surface) of the recording medium P is in sliding contact with the tip 31a of the sheet-like member 31 (as shown in FIG. 5A), the recording medium P is conveyed by the conveying rollers 26 and 27. And until the leading edge of the recording medium P reaches the registration rollers 17 and 18.) When the leading edge 31a of the sheet-like member 31 is inclined with respect to the recording medium P, the abdomen of the recording medium P And the sheet edge sliding noise between the sheet-like member 31 and the tip 31a of the sheet-like member 31 are increased. The sheet edge sliding noise increases the inclination angle α when the trailing edge of the recording medium P passes through the nip of the conveying rollers 26 and 27 and the recording medium P is conveyed by the registration rollers 17 and 18. But it hardly changes. However, when the recording medium P is in the state shown in FIG. 5A (when the recording medium P is conveyed so as to be pushed out by the conveying rollers 26 and 27), the inclination angle α is increased. Then, the sheet edge sliding noise also increases.
Note that this sheet edge sliding contact sound is generated before the time when the peak sound S1 is generated in FIGS. 6 and 7, and is a relatively long time (the abdomen of the recording medium P is the leading end 31a of the sheet-like member 31). This is a time period until the leading edge of the recording medium P reaches the registration rollers 17 and 18 in a state of sliding contact with the recording medium P).
The sheet edge sliding sound as a steady sound measured by the inventor of the present application is 65 db when the inclination angle α of the sheet-like member 31 is fixed to 0 degree, and the inclination angle α of the sheet-like member 31 is 0. When it was fixed at 4 degrees, it was 67 db, and when the inclination angle α of the sheet-like member 31 was fixed at 1.1 degrees, it was 68 db.
Such a phenomenon occurs because the range of the abdomen of the recording medium P that is in sliding contact with the tip 31a of the sheet-like member 31 is increased as the inclination angle α of the tip 31a of the sheet-like member 31 is increased.

As described above, the peak sound S2 generated when the rear end Pb of the recording medium P passes the front end 31a of the sheet-like member 31, and the peak generated when the abdomen of the recording medium P slides on the front end 31a of the sheet-like member 31. Sound (sliding contact sound) has a trade-off relationship. That is, the inclination angle α of the sheet-like member 31 is set extremely large and fixed in order to reduce the peak sound S2 generated when the rear end Pb of the recording medium P passes through the tip 31a of the sheet-like member 31. Then, the peak sound generated when the abdomen of the sheet-like member 31 is in sliding contact with the tip 31a of the sheet-like member 31 becomes large and cannot be ignored.
In the present embodiment, in consideration of such a balance between the peak sounds, the inclination angle of the leading end 31a of the sheet-like member 31 until just before the trailing end Pb of the recording medium P reaches the leading end 31a of the sheet-like member 31. When α is set to 0 degree, immediately before the trailing edge Pb of the recording medium P reaches the leading edge 31a of the sheet-like member 31, the inclination angle α of the leading edge 31a of the sheet-like member 31 is 0.4 degrees or more. It is set to be 1 degree or less (0.4 degree ≦ α ≦ 1.1 degree). Further, even if the leading end 31a of the sheet-like member 31 is inclined and installed at a slight inclination angle α (0.4 ° ≦ α ≦ 1.1 °) for a short time, the recording medium passes therethrough. It hardly affects the transportability of P.

  In the experiment described with reference to FIGS. 5 to 7, the sound (peak sound) generated when the recording medium P conveyed from the manual sheet feeding unit 25 interferes with the sheet-like member 31 has been described. The recording medium P conveyed from 12 to 14 also generates a sound (peak sound) by interfering with the sheet-like member 31 by the same mechanism. Sound generation can be reduced almost in the same way.

Here, in the present embodiment, as shown in FIG. 2, a paper thickness sensor 42 is installed as a detecting means for detecting the thickness of the transported recording medium P, and the recording detected by the paper thickness sensor 42 is performed. Only when the thickness (basis weight) of the medium P is equal to or greater than a predetermined value, the rotation control of the sheet-like member 31 described above with reference to FIGS. 3 and 4 can be performed.
Specifically, FIG. 8 is a graph showing the degree of sound generated in the vicinity of the conveying device 30 when the recording medium P having a basis weight of 128 g / m ² is passed, and is the position shown in FIG. The sound pressure level measured by the microphone 100 installed at (M = 30 cm, N = 20 cm) is shown. Thus, when the thickness (basis weight) of the recording medium P is relatively small, the stiffness of the recording medium P is relatively weak, so that the trailing edge Pb of the recording medium P passes through the leading edge 31a of the sheet-like member 31. The peak sound S2 generated when the sound is generated is also relatively small. However, when the basis weight of the recording medium P is increased with 128 g / m ² as a threshold, the peak sound S2 generated when the trailing end Pb of the recording medium P passes the leading end 31a of the sheet-like member 31 cannot be ignored. Only when the basis weight of the recording medium P detected by the paper thickness sensor 42 is larger than a predetermined value (128 g / m ² ), the sheet shape by the rotating means 33 to 37 described above with reference to FIGS. The rotation control of the member 31 is performed. Thereby, the noise generated in the conveying device 30 can be efficiently reduced without performing unnecessary rotation of the sheet-like member 31.
As a detecting means for detecting the thickness of the recording medium P, a known paper thickness sensor that directly detects the thickness of the recording medium P using a laser beam or the like can be used. It is also possible to use known detection means for indirectly detecting the thickness of the recording medium P from information input to the section.

In the present embodiment, as shown in FIG. 2, a microphone 43 is installed as a measuring means for measuring the sound generated when the trailing end Pb of the recording medium P passes through the leading end 31a of the sheet-like member 31. 4B, immediately after the rear end Pb of the recording medium P to be passed next reaches the front end 31a of the sheet-like member 31 when the loudness measured by the microphone 43 is equal to or greater than a predetermined value. It is also possible to rotate the sheet-like member 31 in this state.
Specifically, FIG. 9 is a graph showing the degree of sound generated in the vicinity of the conveying device 30 when the recording medium P is passed under a predetermined condition, and is a microphone 43 installed at the position of FIG. The data (sound data collected by the microphone 43) indicating the sound pressure level measured by the above. Even when the recording medium P having the same basis weight is passed through the same apparatus main body 1, if the conditions such as the temperature and humidity environment are different, the stiffness of the recording medium P changes, and the recording medium P The magnitude of the peak sound S2 that occurs when the rear end Pb passes the front end 31a of the sheet-like member 31 may change. Therefore, in the sound data collected by the microphone 30, the range before and after the peak sound S <b> 2 is generated (for example, the time H when the rear end Pb of the recording medium P obtained by the control unit 46 reaches the front end 31 a of the sheet-like member 31. Is within a range of ± 0.05 seconds), the largest sound is identified as the peak sound S2. Then, when the specified peak sound S2 exceeds a predetermined value Q (for example, 73 dB) as shown in FIG. 9, it is assumed that the sound is annoying for the user, and the recording medium P that is subsequently passed through is recorded. In contrast, the rotation of the sheet-like member 31 is controlled to reduce subsequent noise generation. On the other hand, when the specified peak sound S2 does not reach a predetermined value Q (for example, 73 dB), it is determined that the sound is not annoying for the user, and the recording medium P to be subsequently passed is recorded. Also, the rotation control of the sheet-like member 31 is not performed. Thereby, the noise generated in the conveying device 30 can be efficiently reduced without performing unnecessary rotation of the sheet-like member 31.
The time H when the trailing edge Pb of the recording medium P reaches the leading edge 31a of the sheet-like member 31 is based on the time when the leading edge Pa of the recording medium P is detected by the paper detection sensor 41 (photo sensor). The size in the transport direction of P, the transport distance from the paper detection sensor 41, the transport speed of the recording medium P, the response time from when the stepping motor 37 receives a control command until the drive is started, the rotation angle or rotation of the stepping motor 37 It is obtained by the control unit 46 in consideration of the speed and the like.

  In the present embodiment, the sheet-like member 31 is rotated together with the guide plate 32 (guide member) by the rotation means 33 to 37, but the sheet-like member 31 is guided by the rotation means configured in another form. The plate 32 (guide member) can be independently rotated. In this case, the same effect as that of the present embodiment can be obtained.

  As described above, in the present embodiment, the sheet-like member 31 installed so as to protrude from the tip end portion of the guide plate 32 (guide member) is at least the recording medium P at the tip position 31a of the sheet-like member 31. Since the leading end 31a of the protruding portion is rotated by the rotating means 33 to 37 so as to be inclined with respect to the width direction of the recording medium P until the trailing end Pb reaches, the leading end position 31a of the sheet-like member 31 is reached. Harsh sound that occurs when the rear end Pb of the recording medium P passes through can be reduced.

In the present embodiment, the present invention is applied to the conveyance device 30 installed in the monochrome image forming apparatus 1. However, the present invention is naturally applied to the conveyance device installed in the color image forming apparatus. Can be applied.
In the present exemplary embodiment, the present invention is applied to the conveyance device 30 that conveys the recording medium P toward the image forming unit. However, the conveyance device conveys the recording medium P toward other positions. Of course, the present invention can also be applied to a conveying device provided that the conveying device includes a guide member in which a sheet-like member is installed so as to protrude from the tip.
Further, in the present embodiment, the present invention is applied to the conveyance device 30 installed in the electrophotographic image forming apparatus 1, but the application of the present invention is not limited to this, and other methods can be used. Even if it is a conveying apparatus installed in an image forming apparatus (for example, an inkjet image forming apparatus), it may be a conveying apparatus provided with a guide member in which a sheet-like member is installed so as to protrude from the leading end. For example, the present invention can naturally be applied to all of these transport apparatuses.
Even in those cases, the same effects as in the present embodiment can be obtained.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1 image forming apparatus body (apparatus body),
30 transport device,
31 Sheet-like member (flexible member),
31a tip,
32 guide plate (guide member),
33 Rotating shaft, 34, 35 Pulley (timing pulley),
36 timing belt, 37 stepping motor (rotating means),
41 Paper detection sensor,
42 Paper thickness sensor (detection means),
43 Microphone (measuring means), P recording medium.

JP 2007-106551 A JP-A-4-59540

Claims (8)

A transport device for transporting a recording medium,
A guide member provided with a sheet-like member installed so as to be guided so that the recording medium is conveyed in a predetermined direction and protruded from a leading end located downstream in the conveyance direction of the recording medium;
Rotation means for rotating the sheet-like member in parallel with respect to the conveying surface of the sheet-like member;
The rotating means has a predetermined inclination angle with respect to the width direction at least when the trailing end of the recording medium reaches the leading end position of the protruding portion of the sheet-like member protruding from the leading end portion. The conveying apparatus is characterized in that the sheet-like member is rotated so as to be inclined at a point. The rotating means is
By rotating the sheet-like member so that the tip of the projection is parallel to the width direction at least by the time when the tip of the recording medium reaches the tip of the projection of the sheet-like member,
The sheet-like member is rotated so that the leading end of the protruding portion is inclined at a predetermined inclination angle with respect to the width direction immediately before the rear end of the recording medium reaches the leading end position of the protruding portion of the sheet-like member. The conveying apparatus according to claim 1, wherein   The transport apparatus according to claim 1, wherein the predetermined inclination angle is not less than 0.4 degrees and not more than 1.1 degrees. A detecting means for directly or indirectly detecting the thickness of the recording medium to be conveyed;
When the thickness of the recording medium detected by the detecting means is equal to or greater than a predetermined value, the rotating means is at least when the rear end of the recording medium reaches the leading end position of the protruding section. The conveying apparatus according to any one of claims 1 to 3, wherein the sheet-like member is rotated so that a tip thereof is inclined at the predetermined inclination angle. Measuring means for measuring a sound generated when the rear end of the recording medium passes through the leading end position of the protruding portion of the sheet-like member;
The rotating means has at least the time when the trailing edge of the recording medium to be passed next reaches the leading edge position of the protrusion when the loudness measured by the measuring means is equal to or greater than a predetermined value. The conveying device according to any one of claims 1 to 4, wherein the sheet-like member is rotated so that a tip of the protruding portion is inclined at the predetermined inclination angle. The sheet-like member is fixed to the guide member so that the protruding portion protrudes in parallel to the tip end portion of the guide member,
The conveying device according to claim 1, wherein the rotating unit rotates the sheet-like member together with the guide member.   The said guide member is arrange | positioned so that the said protrusion part of the said sheet-like member may protrude toward the confluence | merging part where a some conveyance path merges. The conveying apparatus as described in.   An image forming apparatus comprising the transport device according to claim 1.

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