JP2008019050A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing occurrence of abnormal sound (buckling sound) caused when a conveyed recording paper comes into contact with a register roller. <P>SOLUTION: In this image forming device, a recessed part 42 allowing a recording paper conveyed in a common conveyance passage 36 to bend is formed in a first conveyance guide part 38 for forming and partitioning the common conveyance passage 36 so that the recording paper conveyed in the common conveyance passage 36 is freely bent along the recessed part 42. Consequently, since the recording paper comes into contact with the register roller 20 in a bent condition, the recording paper is not buckled. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms predetermined information on a recording sheet.

  The conventional image forming apparatus includes an image forming apparatus main body, a main cassette housed in a lower part of the image forming apparatus body, an option cassette housed in a lower part of the image forming apparatus body and below the main cassette, and a manual feed. And a tray.

As shown in FIG. 3, inside the image forming apparatus main body 100, a main transport path 102 through which recording paper that has been registered by the registration rollers 114 is transported, and recording paper stored in the main cassette are transported. A first conveyance path 104, a second conveyance path 106 through which recording paper stored in an option cassette is conveyed, a third conveyance path 108 through which recording paper on the manual feed tray is conveyed, and reverse conveyance to reverse the recording paper A path 110 and a common transport path 112 communicating with each of the transport paths 104, 106, 108, 110 are formed. In addition, a registration roller 114 for correcting skew (registration) of all the recording sheets conveyed through the common conveyance path 112 is disposed inside the image forming apparatus main body 100.
JP-A-9-86728 Japanese Patent Laid-Open No. 9-30688

  By the way, in the image forming apparatus, the recording paper conveyed from the option cassette reaches the registration roller from the second conveyance path through the common conveyance path. However, the recording paper conveyed from the option cassette is transferred by the registration roller. Only when the registration is performed, there is a problem that the recording paper in contact with the registration roller is buckled without being bent and a large noise (buckling noise) is generated.

  In view of the above-described circumstances, the present invention provides an image forming apparatus that can prevent abnormal noise (buckling noise) from occurring when the conveyed recording paper contacts the registration roller. Objective.

  The invention according to claim 1 is a cassette-side conveyance path through which recording paper contained in a cassette is conveyed, a common conveyance path that is connected to the cassette-side conveyance path at a predetermined angle and that conveys recording paper, and A registration roller that corrects the skew of the recording paper that has been conveyed through the common conveyance path, rotates after the correction is completed, and conveys the recording paper to the downstream side in the conveyance direction; and a first conveyance guide section that partitions the common conveyance path; An image forming apparatus having a second conveyance guide section that partitions the cassette-side conveyance path, wherein the cassette-side conveyance path and the common conveyance path are formed in a substantially linear shape, and the first conveyance guide The portion is formed with a recess that allows bending of the recording paper transported through the common transport path.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, one end of the common conveyance path is positioned in the vicinity of the registration roller, and the other end of the common conveyance path is the It is connected to a cassette side conveyance path, and the concave portion is formed at a portion other than the one side end and the other side end of the common conveyance path.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, a curved conveyance path that is formed in a curved shape and is conveyed while the recording paper is bent, and a sensor that detects the recording paper The skew of the recording paper conveyed in a state where the curved conveying path is bent is corrected by the registration roller, and after the correction is completed, the registration roller rotates to move the recording paper downstream in the conveyance direction. First registration time from when the sensor detects the recording paper that has been conveyed to the cassette side and conveyed through the cassette-side conveyance path to reach the registration roller through the common conveyance path, until rotation of the registration roller starts. Is shorter than the second registration time from when the sensor detects the recording paper conveyed through the curved conveyance path and reaching the registration roller until the registration roller starts to rotate. Characterized in that it is set to so that.

  According to the first aspect of the present invention, the inventor repeated experiments and trial and error on the cause of the abnormal noise generated when the recording paper conveyed through the cassette side conveyance path contacts the registration roller. As a result, the inventor has found that the cause is that the recording paper is buckled in the common conveyance path upstream of the registration rollers in the conveyance direction. That is, the inventor records by correcting the skew by the registration roller by connecting the linear cassette side conveyance path and the linear common conveyance path at a predetermined angle so as to swell outward. Although the paper was expected to bend outward, the recording paper was actually trying to bend inward in the common transport path. As a result, the recording paper was in contact with the registration roller without bending. This has been found to be caused by the fact that both the common transport path and the cassette-side transport path are set linearly.

  Therefore, by forming a recess allowing the deflection of the recording paper transported along the common transport path in the first transport guide section that defines the common transport path, the recording paper transported along the common transport path can be freely moved along the recess. Can be bent. As a result, the recording paper comes into contact with the registration roller in a bent state, so that the recording paper does not buckle. As a result, it is possible to prevent abnormal noise (buckling noise) from occurring when the recording paper comes into contact with the registration roller.

  According to the second aspect of the present invention, since the concave portion is formed at a portion other than the one end portion of the common conveyance path, the recording paper is conveyed when the recording paper is conveyed from the common conveyance path to the registration roller side. The recording paper can be smoothly guided in a predetermined direction without the leading end of the recording medium being caught in the recess. In addition, since the concave portion is formed in a portion other than the other end portion of the common conveyance path, when the recording paper is conveyed from the cassette side conveyance path to the common conveyance path, the leading edge of the recording paper is caught by the concave portion. The recording paper can be smoothly guided in a predetermined direction.

  According to the third aspect of the present invention, the first registration until the rotation of the registration roller starts after the sensor detects the recording paper that has been conveyed on the cassette side conveyance path and reached the registration roller via the common conveyance path. The time is set to be shorter than the second registration time from when the sensor detects the recording paper that has been conveyed through the curved conveyance path and reached the registration roller until the registration roller starts to rotate. As a result, the registration time of the recording paper that is transported through the cassette-side transport path and reaches the registration roller via the common transport path is relatively short, so that the generation of abnormal noise can be suppressed, and the orientation control of the recording paper can be performed in a short time. Can be completed.

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

  As shown in FIGS. 1 and 2, the image forming apparatus 10 includes an image forming apparatus main body 12 serving as a main body. A main cassette 14 in which recording sheets are stacked is housed in the lower part of the image forming apparatus main body 12. An option cassette (cassette) 16 in which recording sheets are stacked is housed in the lower part of the image forming apparatus main body 12 and below the main cassette 14. A manual feed tray 18 is provided on the side surface of the image forming apparatus main body 12. Further, inside the image forming apparatus main body 12, a registration roller 20 that corrects skew of a recording sheet conveyed through a common conveyance path 36 to be described later and rotates after the correction is completed to convey the recording sheet downstream in the conveying direction. Is arranged. When the skew of the recording paper is corrected by the registration roller 20, the registration roller 20 rotates and the recording paper is conveyed downstream in the conveyance direction (on the main conveyance path 26 side). Further, a registration sensor (sensor) 22 for detecting the conveyed recording paper is provided on the upstream side of the registration roller 20 in the recording paper conveyance direction. Further, on the upper surface of the image forming apparatus main body 12, a paper discharge tray 24 for discharging recording paper on which an image is formed is formed. Note that an image forming unit (not shown) that forms an image on the recording paper conveyed downstream in the recording paper conveyance direction by the registration roller 20 is provided inside the image forming apparatus main body 12.

  In addition, a main conveyance path 26 is formed inside the image forming apparatus main body 12 for conveying the recording paper that has been registered by the registration rollers 20. The main transport path 26 communicates with the paper discharge tray 24. Further, a curved first transport path (curved transport path) 28 through which the recording paper stored in the main cassette 14 is transported is formed inside the image forming apparatus main body 12. In addition, a substantially linear second transport path (cassette side transport path) 30 through which the recording paper stored in the option cassette 16 is transported is formed inside the image forming apparatus main body 12. The second transport path 30 is partitioned and formed by the second transport guide portion 40 so as to be substantially linear. Further, a curved third conveyance path (curved conveyance path) 32 through which the recording paper on the manual feed tray 18 is conveyed is formed inside the image forming apparatus main body 12. A curved reversing conveyance path (curved conveyance path) 34 for reversing the recording paper is formed inside the image forming apparatus main body 12.

  Further, a common conveyance path 36 is partitioned and formed by the first conveyance guide portion 38 inside the image forming apparatus main body 12 so as to be substantially linear. The third conveyance path 32 through which the recording sheet on the manual feed tray 18 is conveyed is connected to the recording sheet conveyance upstream side of the common conveyance path 36. The first transport path 28 through which the recording paper stored in the main cassette 14 is transported is connected to the upstream side of the registration roller 20 in the recording paper transport direction and to the downstream side of the common transport path 36. . One end of the reverse conveyance path 34 is connected to the main conveyance path 26, and the other end is connected to the recording paper conveyance downstream side of the common conveyance path 36 near the upstream side of the registration roller 20 in the recording paper conveyance direction. The second transport path 30 through which the recording paper stored in the option cassette 16 is transported is connected to the upstream side of the registration roller 20 in the recording paper transport direction and to the upstream side of the common transport path 36. . That is, the second conveyance path 30 extends in the vertical direction, and the common conveyance path 36 and the second conveyance path 30 are connected at a predetermined angle so as to swell outward.

  Here, a concave portion 42 that allows bending of the conveyed recording paper is formed at a substantially intermediate portion in the recording paper conveyance direction of the first conveyance guide portion 38 that defines the common conveyance path 36. Further, the concave portion 42 includes a downstream end portion (one side end portion, an end portion on the registration roller 20 side) 38Y of the common transport path 36 of the first transport guide portion 38 and an upstream end portion in the recording paper transport direction. It is preferable to be formed in a portion other than the portion (the other side end, the end on the second conveyance path 30 side) 38X.

  Further, the first registration time from when the registration sensor 22 detects the recording paper conveyed through the second conveyance path 30 and reaching the registration roller 20 via the common conveyance path 36 until the registration roller 20 starts to rotate is Set to be shorter than the second registration time until the registration roller 20 starts to rotate after the recording paper that has been conveyed through the other conveyance paths 28, 32, and 34 and reaches the registration roller 20 is detected by the registration sensor 22. Has been. Specifically, the first registration time is set to 140 msec, and the second registration time is set to 170 msec.

  Next, the operation of the image forming apparatus 10 according to an embodiment of the present invention will be described.

  As shown in FIGS. 1 and 2, the recording paper stored in the option cassette 16 is transported through the second transport path 30 and further transported through the common transport path 36 to reach the registration rollers 20. Further, the recording paper stored in the main cassette 14 is conveyed through the first conveyance path 28 and reaches the registration roller 20. The recording paper on the manual feed tray 18 is conveyed through the third conveyance path 32 and reaches the registration roller 20. Further, the recording paper conveyed from the main conveyance path 26 to the reverse conveyance path 34 is reversed in the process of being conveyed along the reverse conveyance path 34 and reaches the registration roller 20.

  Here, the inventor repeated experiment and trial and error about the cause of the noise generated when the recording paper conveyed through the second conveyance path 30 contacts the registration roller 20. As a result, the inventor has found that the cause is that the recording paper is buckled in the common conveyance path 36 located upstream in the conveyance direction of the registration roller 20. That is, the inventor corrects the skew by the registration roller 20 by connecting the linear second conveyance path 30 and the linear common conveyance path 36 with a predetermined angle so as to swell outward. The recording paper was expected to bend outward, but in reality, the recording paper tried to bend inward in the common conveyance path 36. However, since the recording sheet is bent inward, it is conveyed through the second conveyance path 30 and the common conveyance path 36 connected at a predetermined angle so as to swell outward. Deflection was prevented by the side wall of the common conveyance path 36. As a result, the recording paper was in contact with the registration roller 20 without being bent inward. This has been found to be caused by the fact that both the common conveyance path 36 and the second conveyance path 30 are set in a straight line.

  Therefore, the recording paper transporting the common transport path 36 is formed by forming a recess 42 that allows the recording paper transporting the common transport path 36 to bend in the first transport guide portion 38 that defines the common transport path 36. It becomes possible to bend freely along the recess 42. Thereby, since the recording paper comes into contact with the registration roller 20 in a bent state, the recording paper does not buckle. As a result, it is possible to prevent abnormal noise (buckling noise) from occurring when the recording paper comes into contact with the registration roller 20.

  Further, since the concave portion 42 is formed in a portion other than the downstream end portion (one end portion, the end portion on the registration roller 20 side) 38Y of the common transport path 36 in the recording paper transport direction, the recording paper is in the common transport path 36. Therefore, the recording paper can be smoothly guided in a predetermined direction without the leading edge of the recording paper being caught by the concave portion 42 when being conveyed to the registration roller 20 side. In addition, since the concave portion 42 is formed at a portion other than the upstream end portion (the other end portion, the end portion on the second transport path 30 side) 38X of the common transport path 36 in the recording paper transport direction, the recording paper is second. When the recording paper is conveyed from the conveyance path 30 to the common conveyance path 36, the leading end of the recording paper is not caught by the recess 42, and the recording paper can be smoothly guided in a predetermined direction.

  Further, the first registration time from when the registration sensor 22 detects the recording paper conveyed through the second conveyance path 30 and reaching the registration roller 20 via the common conveyance path 36 until the registration roller 20 starts to rotate is as follows: Set to be shorter than the second registration time until the registration roller 20 starts to rotate after the recording paper that has been conveyed through the other conveyance paths 28, 32, and 34 and reaches the registration roller 20 is detected by the registration sensor 22. Has been. As a result, the registration time of the recording paper conveyed through the second conveyance path 30 and reaching the registration roller 20 via the common conveyance path 36 becomes relatively short, so that the generation of abnormal noise can be suppressed and the attitude control of the recording paper can be performed. Can be completed in a short time.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. 1 is an enlarged view of a main part of an image forming apparatus according to an embodiment of the present invention. It is the figure which expanded the principal part of the image forming apparatus used as a prior art.

Explanation of symbols

10 Image forming device 16 Option cassette (cassette)
20 Registration roller 22 Registration sensor (sensor)
28 1st conveyance path (curved conveyance path)
30 Second transport path (cassette side transport path)
32 3rd conveyance path (curved conveyance path)
34 Inverted conveyance path (curved conveyance path)
36 Common transport path 38 First transport guide section 40 Second transport guide section 42 Recess

Claims (3)

A cassette-side conveyance path through which the recording paper stored in the cassette is conveyed, a common conveyance path that is connected to the cassette-side conveyance path at a predetermined angle and that conveys the recording paper, and a recording that has been conveyed through the common conveyance path A registration roller that corrects the skew of the paper and rotates after completion of correction to transport the recording paper downstream in the transport direction, a first transport guide section that partitions the common transport path, and a partition that forms the cassette-side transport path An image forming apparatus having a second conveyance guide unit,
The cassette side conveyance path and the common conveyance path are formed in a substantially linear shape,
The image forming apparatus according to claim 1, wherein the first conveyance guide portion is formed with a recess that allows bending of the recording paper that is conveyed along the common conveyance path. One end of the common conveyance path is located in the vicinity of the registration roller, and the other end of the common conveyance path is connected to the cassette-side conveyance path,
The image forming apparatus according to claim 1, wherein the concave portion is formed in a portion other than the one end portion and the other end portion of the common conveyance path. A curved conveyance path that is formed in a curved shape and conveyed in a bent state, and a sensor that detects the recording paper,
The skew of the recording paper that has been conveyed in a bent state in the curved conveying path is corrected by the registration roller, and after the correction is completed, the registration roller rotates to convey the recording paper downstream in the conveyance direction,
The first registration time from when the sensor detects the recording paper conveyed through the cassette side conveyance path and reaching the registration roller via the common conveyance path until the registration roller starts to rotate is the curved shape. It is set so as to be shorter than a second registration time from when the recording paper conveyed through the conveyance path to the registration roller is detected by the sensor until the registration roller starts to rotate. The image forming apparatus according to claim 1.

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