JP4563963B2 - Paper transport device, image forming device - Google Patents

Description

  The present invention relates to a sheet conveying apparatus and an image forming apparatus, and more particularly to a sheet conveying apparatus capable of reliably conveying a conveying path having a large curvature even with stiff recording paper and an image recording apparatus including the recording conveying apparatus.

  2. Description of the Related Art Conventionally, in order to reduce the size of an image forming apparatus such as a copying machine or a printer, a paper conveyance device that conveys a recording paper fed from a recording paper storage unit that stores the recording paper has also been miniaturized. For this reason, the radius of curvature of the curvature portion of the conveyance path of the sheet conveying apparatus is configured to be relatively small so that the standard recording sheet can be conveyed.

  There are the following as a sheet conveying device used in such an image forming apparatus. FIG. 5 is a cross-sectional view showing a conventional paper conveying apparatus. The sheet conveying apparatus 100 includes a pickup roller 103 that separates one sheet of recording paper S from a bundle of recording sheets P stored in a paper feed tray 101, and a downstream of the recording sheet S from the pickup roller 103 along a substantially horizontal direction. A feed roller 104 and a reverse roller 105 that are conveyed toward the rear. The pickup roller 103, the feed roller 104, and the reverse roller 105 operate as recording paper separating means.

  The sheet conveying apparatus 100 is a guide unit that changes the conveying direction of the recording sheet S sent from the feed roller 104 and the reverse roller 105 to a direction substantially perpendicular to the conveying direction of the recording sheet separating unit. The upper conveyance guide unit 106 and the lower conveyance guide unit 107 are provided with a curved passage 108. A recording paper transport path 109 for further guiding the recording paper S along the direction (upward) changed by the guide section is provided at the outlet (downstream) of the upper transport guide section 106 and the lower transport guide section 107. The recording paper transport path 109 is provided with a roller-type transport unit including two grip rollers 110 and 111 that transport the recording paper S with the recording paper S interposed therebetween, and constitutes a transport means. In the figure, reference numeral 112 denotes a recording paper conveyance path from another paper feed tray (not shown) disposed below, and the recording paper conveyance path 112 joins the recording paper conveyance path 109. The recording sheet S conveyed from the other sheet feeding tray is transferred from the recording sheet conveying path 112 to the recording sheet conveying path 109.

  As described above, there is an image forming apparatus described in Patent Document 1 as a downsized image forming apparatus. In Patent Document 1, a plurality of paper feeding units arranged in the horizontal direction are arranged in a stacked manner, and the recording paper supplied from each paper feeding unit is guided from the horizontal direction to the upper side in a substantially vertical direction, and its path is changed. It is described as being bent and transported by a transport device comprising a transport belt.

JP 02-248962 A

  However, in the paper transport device described above, when trying to feed stiff paper such as thick paper or special paper such as an envelope as the recording paper, the curvature radius of the curvature portion of the transport path is small, so the recording paper May not be able to travel along the conveying path constituting the curvature portion. In such a case, there is a problem that a jam or a conveyance failure occurs and a stable feeding operation cannot be performed.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying apparatus and an image forming apparatus that can stably feed a recording sheet even when a conveying path having a small radius of curvature is provided.

The invention of claim 1 is a recording paper separating means for separating the stored recording paper and conveying it downstream.
A guide section for changing the conveyance direction of the recording paper from the recording paper separating means to a direction substantially perpendicular to the conveyance direction of the recording paper separating means;
A recording paper conveyance path that is arranged downstream of the guide portion and guides the recording paper further downstream along the direction changed by the guide portion;
A conveying unit that is disposed in the recording paper conveyance path and includes a roller-type transfer unit that conveys the recording paper with the recording paper interposed therebetween;
In a paper transport device comprising:
Auxiliary conveyance means for assisting conveyance of the conveyance means is provided in the conveyance path ,
The auxiliary conveying means is a belt type conveying means configured to include a conveying belt,
The belt conveying means, Ru provided with a driving means different from a driving means for driving the roller conveyer unit of the conveying means,
This is a sheet conveying apparatus.

The invention of claim 2 is a recording paper separating means for separating the stored recording paper and conveying it downstream.
A guide section for changing the conveyance direction of the recording paper from the recording paper separating means to a direction substantially perpendicular to the conveyance direction of the recording paper separating means;
A recording paper conveyance path that is arranged downstream of the guide portion and guides the recording paper further downstream along the direction changed by the guide portion;
A roller-type transfer unit that is arranged in the recording paper conveyance path and transfers the recording paper with the recording paper interposed therebetween;
Transport means for transporting the recording paper along the recording paper transport path;
In a paper transport device comprising:
Auxiliary conveyance means for assisting conveyance of the conveyance means is provided in the conveyance path,
The auxiliary conveying means, Ri was configured with a conveyor belt belt conveying means der,
The belt conveying means, Ru is driven by a shaft with different axes for driving the roller conveyer unit of the conveying means,
It is characterized by that.

A third aspect of the present invention, the paper conveyance apparatus according to claim 1 or 2, wherein the conveyor belt of the belt conveyor means are formed by at least the contact surfaces electrically conductive material of said recording paper and said Rukoto .

According to a fourth aspect of the present invention, in the paper conveying apparatus according to any one of the first to third aspects, a plurality of the recording paper separating means are arranged, and a plurality of the guide portions are provided corresponding to the recording paper separating means,
Each of the guide portions is configured to guide the recording paper to a common conveyance path,
The conveyance path is provided with conveyance means corresponding to each of the guide sections, and a single belt-type conveyance means for assisting conveyance of the recording paper from all the guide sections is arranged on the conveyance path. that,
It is characterized by that.

The invention of claim 5 is an image forming apparatus comprising the sheet conveying device according to any one of claims 1 to 4.

  In the paper conveying apparatus and the image forming apparatus according to the present invention, the auxiliary conveying means for assisting the conveying means is provided in the conveying path, so that the recording paper can be stabilized even if the conveying path having a small radius of curvature is provided. The effect is that you can feed.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  Embodiments of an image forming apparatus according to the present invention will be described below with reference to FIGS. FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus including a paper feeding unit.

  In this example, the image forming apparatus is a full-color printer 10, and four image forming units 21Y and 21M corresponding to yellow (Y), magenta (M), cyan (C), and black (K) are included in the printer 10. , 21C, 21K, and a writing unit 24 for writing an image with a laser beam in these image forming portions 21Y, 21M, 21C, 21K. The image forming units 21Y, 21M, 21C, and 21K are each provided with a photosensitive drum, a static eliminator, a developing unit, a transfer unit, and a cleaning unit. A yellow toner image, a magenta toner image, and a cyan are arranged on each photosensitive drum. A toner image and a black toner image are formed.

  Further, the printer 10 includes a paper transport device 30. The sheet conveying device 30 includes three sheet feeding units 19, 19a, and 19b, and the recording sheet S fed from one of the sheet feeding units 19, 19a, and 19b is supplied to the image forming units 21Y to 21K. The toner images of the respective colors are superimposed and transferred from the image forming units 21Y to 21K onto the transported recording paper S by the transfer belt 20 disposed oppositely. The recording paper to which the toner image has been transferred passes through the fixing device 22, and at this time, the toner image is fixed on the recording paper by the action of heat and pressure. The recording sheet that has passed through the fixing device 22 is discharged onto a discharge tray 25.

  As described above, the image forming apparatus of the present example includes the image forming unit that forms an image on the recording paper, and the paper feeding unit 19, 19a, and 19b that feeds the recording paper to the image forming unit. . Here, the first paper feeding device unit 19 is configured as a manual paper feeding device unit that feeds the recording paper P manually set on the paper feeding tray 11 by the user. The paper device units 19a and 19b feed the recording paper P stacked on the paper feed trays 11a and 11b.

  Any of the paper feeding device sections 19, 19a, 19b has pickup rollers 12, 12a, 12b as recording paper separating means for feeding the stacked recording paper P, and the recording paper transport direction more than the pickup rollers 12, 12a, 12b. Feed rollers 13, 13a, 13b arranged on the downstream side, and reverse rollers 14, 14a, 14b that make contact with the rollers 13, 13a, 13b in pairs with the feed rollers 13, 13a, 13b, respectively As common elements, grip rollers 15a and 15b, a registration roller pair 23, and a recording paper detection means 31 configured as a registration sensor are arranged downstream of the feed roller 13 and the reverse roller 14 in the recording paper conveyance direction. Have.

  The recording paper P sent out from each of the paper feed trays 11, 11a, 11b hits the registration roller pair 23, temporarily stops, and then the registration roller pair 23 starts rotating at a predetermined timing. The toner images on the photoconductors of the forming units 21Y to 21K are fed between the photoconductor and the transfer belt 20 at a timing at which the toner images are correctly transferred onto the recording paper.

  In the sheet conveying apparatus according to this example, the recording sheet P fed from the feed roller 13b for the downsizing of the entire apparatus is gripped on the downstream side, particularly in the sheet feeding unit 19b disposed in the lower stage. This is adopted in a feeding device having a configuration in which the conveying direction is suddenly changed before reaching the roller 15b.

  FIG. 2 is a cross-sectional view showing the paper feeding device unit located in the lower stage among the paper feeding device units of the printer described above. The paper feeding device unit 19b according to this example has a pickup roller 12b that separates one recording paper S from a bundle of recording paper P stored in the paper feeding tray 11b, and a recording paper S from the pickup roller 12b substantially horizontally. A feed roller 13b and a reverse roller 14b are provided for transporting downstream in the direction. The pickup roller 12b, feed roller 13b, and reverse roller 14b operate as recording paper separating means.

  Further, the sheet conveying device 30 is a guide portion that changes the conveying direction of the recording sheet S sent from the feed roller 13b and the reverse roller 14b to a direction substantially perpendicular to the conveying direction of the recording sheet separating means. An upper conveyance guide portion 17b and a lower conveyance guide portion 18b are provided, and a curved recording paper conveyance path 32 is provided therebetween. Further, a recording paper transport path 33 for further guiding the recording paper S along the direction (upward) changed by the guide section at the outlet (downstream side) of the upper transport guide section 17b and the lower transport guide section 18b. It has. In this example, two grip rollers 15 b and 16 b that transport the recording paper S with the recording paper S interposed therebetween are disposed in the recording paper conveyance path 33. Further, in this example, a belt-type conveyance device 40 is disposed in the recording paper conveyance path 33 as auxiliary conveyance means.

  FIG. 3 is a perspective view illustrating the configuration of the sheet conveying apparatus according to the embodiment. The belt-type conveyance device 40 according to this example is configured by spanning a non-supporting belt member 41 made of a conductive material, for example, a conductive synthetic resin, over a driving roller 42 and a driven roller 43. The unsupported belt member 41 is disposed in the recording paper transport path 33 and is guided by contact of the leading end of the recording paper S that has passed through the recording paper transport path 32.

  In this example, two sets of the unsupported belt member 41, the driving roller 42, and the driven roller 43 are arranged in parallel, and the two driving rollers 42 arranged in parallel are driven by the rotating shaft 44. The rotary shaft 44 is driven by a drive shaft 47 driven by a motor (not shown) via spur gears 45 and 46. In addition, it is preferable that the conveyance belt rotation speed is larger than the conveyance speed of the recording paper.

  In this example, the belt-type conveyance device 40 is disposed on a vertical conveyance cover 49 that opens and closes (indicated by an arrow A in FIG. 2) during jam processing, while the motor is disposed on the image forming apparatus main body side. The spur gears 45 and 46 are engaged with each other when the vertical transport cover 49 is closed.

  Further, in this example, the grip roller 15 b is driven by a motor different from the motor of the belt-type transport device 40 via the shaft 34.

  According to this example, when the recording paper S reaches the recording paper conveyance path 33 via the recording paper conveyance path 32, the leading edge is guided by the rotationally driven conveyance belt, and the conveyance force by the belt is also applied, whereby the curvature is increased. Even in a small conveyance path, stable conveyance can be performed.

  In this example, since the unsupported belt member 41 is formed of a conductive member, frictional charging between the recording paper S and the unsupported belt member 41 can be prevented, and stable image quality can be maintained. .

  As described above, in this embodiment, the rotation speed of the conveyance belt can be made larger than the conveyance speed of the recording paper, and the impact load when the recording paper conveyed by the feed roller contacts the conveyance belt can be reduced. It is possible to reduce problems such as the breaking of the leading end of the recording paper, and it is possible to reduce the space and weight of the vertical transport cover.

  In the above example, the belt-type conveying device 40 is provided only in the lower sheet feeding unit 19b. However, it can be provided in the upper sheet feeding unit 19a in the same manner.

  Next, a second embodiment of the paper conveying apparatus according to the present invention will be described. FIG. 4 is a schematic cross-sectional view showing the configuration of the sheet conveying apparatus according to the second embodiment. The paper conveying apparatus according to this example is provided with a belt type conveying apparatus 50. In this example, in the image forming apparatus having the upper and lower two-stage sheet feeding units 19a and 19b, one belt type conveying device 50 is arranged for the sheet feeding units 19a and 19b.

  A pickup roller 12a, a feed roller 13a, a reverse roller 14a, grip rollers 15a and 16a, an upper conveyance guide portion 17a, and a lower conveyance guide portion 18a are arranged in the paper feeding device portion 19a according to this example. Further, the sheet feeding unit 19b has the same structure as that of the first embodiment, and includes a pickup roller 12b, a feed roller 13b, a reverse roller 14b, grip rollers 15b and 16b, an upper conveyance guide unit 17b, The side conveyance guide part 18b is arranged,

  The belt-type transport device 50 according to this example includes an unsupported belt member 51 provided so as to straddle the sheet feeding device unit 19a and the sheet feeding device unit 19b. The unsupported belt member 51 includes a driving roller 52, It is passed to the driven roller 53 and driven.

  According to the paper feeding device section according to the present example, in addition to the operation of the first embodiment, it is possible to suppress the increase in the number of parts and reduce the trouble such as the folding end of the recording paper while reducing the cost. Become.

  In each of the above embodiments, the image forming apparatus has been described as a printer. However, the image forming apparatus may be a copier, a facsimile machine, a multifunction machine having a scanner function, or the like.

1 is a schematic layout diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic cross-sectional view illustrating a configuration of a sheet conveying device of an image forming apparatus according to an embodiment. FIG. 3 is a perspective view illustrating a configuration of a sheet conveying device according to an embodiment. It is a schematic sectional drawing which shows the structure of the paper conveying apparatus which concerns on a 2nd Example. FIG. 6 is a schematic diagram of a configuration of a conventional sheet feeder unit.

Explanation of symbols

10 ... Printer 11, 11a, 11b ... Paper feed tray 12, 12a, 12b ... Pickup rollers 13, 13a, 13b ... Feed rollers 14, 14a, 14b ... Reverse rollers 15b, 16b ..Grip rollers 17a, 17b... Upper conveyance guide portion 18a... Lower conveyance guide portion 18b... Lower conveyance guide portion 19, 19a, 19b. 21Y, 21M, 21C, 21K ... Image forming unit 22 ... Fixing device 23 ... Registration roller pair 24 ... Writing unit 25 ... Paper discharge tray 30 ... Paper transport device 31 ... Recording paper detection means 32... Recording paper transport path 33... Recording paper transport path 34... Shaft 40. 43 ... driven roller 44 ... rotating shaft 45, 46 ... spur gear 47 ... drive shaft 49 ... longitudinal conveying cover 50 ... belt type conveying device 51 ... unsupported belt member 52 ... Drive rollers

Claims (5)

Recording paper separating means for separating the stored recording paper and transporting it downstream;
A guide section for changing the conveyance direction of the recording paper from the recording paper separating means to a direction substantially perpendicular to the conveyance direction of the recording paper separating means;
A recording paper conveyance path that is arranged downstream of the guide portion and guides the recording paper further downstream along the direction changed by the guide portion;
A conveying unit that is disposed in the recording paper conveyance path and includes a roller-type transfer unit that conveys the recording paper with the recording paper interposed therebetween;
In a paper transport device comprising:
Auxiliary conveyance means for assisting conveyance of the conveyance means is provided in the conveyance path ,
The auxiliary conveying means is a belt type conveying means configured to include a conveying belt,
The belt conveying means, Ru provided with a driving means different from a driving means for driving the roller conveyer unit of the conveying means,
A sheet conveying apparatus characterized by the above. Recording paper separating means for separating the stored recording paper and transporting it downstream;
A guide section for changing the conveyance direction of the recording paper from the recording paper separating means to a direction substantially perpendicular to the conveyance direction of the recording paper separating means;
A recording paper conveyance path that is arranged downstream of the guide portion and guides the recording paper further downstream along the direction changed by the guide portion;
A roller-type transfer unit that is arranged in the recording paper conveyance path and transfers the recording paper with the recording paper interposed therebetween;
Transport means for transporting the recording paper along the recording paper transport path;
In a paper transport device comprising:
Auxiliary conveyance means for assisting conveyance of the conveyance means is provided in the conveyance path,
The auxiliary conveying means, Ri was configured with a conveyor belt belt conveying means der,
The belt conveying means, Ru is driven by a shaft with different axes for driving the roller conveyer unit of the conveying means,
A sheet conveying apparatus characterized by the above. The conveyor belt of the belt-type conveying means, at least the recording sheet to the sheet conveying apparatus according to claim 1 or 2, wherein the contact surface is formed of a conductive material, characterized in Rukoto of. A plurality of the recording paper separating means are disposed, and a plurality of the guide portions are provided corresponding to the recording paper separating means,
Each of the guide portions is configured to guide the recording paper to a common conveyance path,
The conveyance path is provided with conveyance means corresponding to each of the guide sections, and a single belt-type conveyance means for assisting conveyance of the recording paper from all the guide sections is arranged on the conveyance path. that,
The sheet conveying apparatus according to claim 1 , wherein the sheet conveying apparatus is provided. An image forming apparatus comprising the sheet conveying device according to any one of 請 Motomeko 1 to 4.