JP2020152467A - Sheet conveyance device and image forming device - Google Patents

Abstract

To prevent foreign matters from being attached to a detection part in a detection sensor.SOLUTION: There are provided a conveying path K for conveying a sheet P in a predetermined conveyance direction, and a detection sensor 63 for optically detecting the sheet P conveyed through the conveying path K. Then, a detection part 63a for receiving reflection light X2 reflected on the sheet P is arranged in the detection sensor 63 so as to be inclined on a downstream side in a conveyance direction, while projecting detection light X1 toward the sheet P.SELECTED DRAWING: Figure 2

Description

The present invention relates to a sheet transporting device for transporting sheets, and an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction device or a printing machine thereof provided with the sheet transporting device.

Conventionally, in a sheet transport device installed in an image forming apparatus such as a copying machine, a printer, or a printing machine, a detection sensor such as a reflective photo sensor that optically detects a sheet transported along a transport path is installed. Is widely known (see, for example, Patent Documents 1 and 2).

Specifically, the detection sensor is arranged so that its detection unit is substantially parallel to the sheet transported along the transport path. In the detection unit of the detection sensor, the detection light emitted from the light emitting element is projected toward the sheet, and the reflected light reflected by the sheet is received by the light receiving element. Then, based on the detection result of the detection sensor that detects the sheet transported along the transport path in this way, jam detection (paper jam detection) is performed by grasping the presence / absence of the sheet, the tip position, the rear end position, and the like. Or, it will be a trigger on various control timings.

On the other hand, in Patent Document 1, for the purpose of detecting plain paper and transparencies without distinguishing them, a reflective sensor (detection sensor) is provided so as to incline upstream of the conveyed sheet above the conveyed sheet. The technique of arranging is disclosed.
Further, Patent Document 2 discloses a technique of blowing air on the light receiving surface of the detection sensor to clean it, for the purpose of preventing the light receiving surface (detection unit) of the detection sensor from becoming dirty.

In the conventional sheet transfer device, when the sheet is conveyed along the transfer path, foreign matter such as paper dust and floating toner flows along with the air flow generated along the transfer direction, and the detection unit (detection surface) of the detection sensor. It sometimes adhered to. If foreign matter adheres to the detection unit in this way, the accuracy of sheet detection by the detection sensor may decrease, and the presence or absence of the sheet may be erroneously detected. Such a defect was also likely to occur in Patent Document 1.
On the other hand, in Patent Document 2, since the detection unit of the detection sensor is cleaned by blowing air, the effect of reducing such a problem can be expected. However, because a supply device that blows air is installed, the cost and size of the device have increased.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a sheet transport device and an image forming device in which foreign matter does not easily adhere to the detection unit of the detection sensor.

The sheet transport device according to the present invention includes a transport path in which the sheet is transported in a predetermined transport direction and a detection sensor that optically detects the sheet transported along the transport path, and the detection sensor is a detection light. The detection unit is arranged so as to be inclined to the downstream side in the transport direction so that the detection unit is projected toward the sheet and receives the reflected light reflected by the sheet.

According to the present invention, it is possible to provide a sheet transfer device and an image forming device in which foreign matter does not easily adhere to the detection unit of the detection sensor.

It is an overall block diagram which shows the image forming apparatus in embodiment of this invention. It is a figure which shows the main part of the sheet transfer apparatus. It is a figure which shows the main part of the conventional sheet transfer apparatus. It is a figure which shows the main part of the sheet transfer apparatus as a modification 1. FIG. It is a figure which shows the main part of the sheet transfer apparatus as a modification 2. It is a figure which shows the main part of the sheet transfer apparatus as a modification 3. It is a figure which shows the main part of the sheet transfer apparatus as a modification 4. It is a figure which shows the main part of the sheet transfer apparatus as a modification 5.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the duplicate description thereof will be appropriately simplified or omitted.

First, FIG. 1 describes the overall configuration and operation of the image forming apparatus 1.
In FIG. 1, 1 is a copying machine as an image forming apparatus, 2 is a document reading unit that optically reads image information of a document D, and 3 is a photoconductor that emits exposure light L based on the image information read by the document reading unit 2. The exposure unit 4 that irradiates the drum 5 is an image forming unit that forms a toner image (image) on the photoconductor drum 5, and 7 is a transfer unit that transfers the toner image formed on the photoconductor drum 5 to the sheet P. (Image forming part).
Further, 10 is a document transporting unit (automatic document transporting device) that transports the set document D to the document reading section 2, and 12 and 13 are feeding devices that feed the sheet P housed in the paper feed cassette. Indicates a manual feeding device for feeding the sheet P manually set by the user.
Further, 17 is a resist roller pair (conveying roller pair) that conveys the sheet P toward the transfer unit 7, 20 is a fixing device that fixes a toner image (unfixed image) supported on the sheet P, and 31 is a device main body. The discharge tray on which the sheet P discharged from 1 is loaded is shown.
Further, 61 to 65 are detection sensors that optically detect whether or not the sheet P is at a predetermined position in the transport path K, and 100 is for displaying various information in the image forming apparatus 1 and inputting various commands. The operation display panel for the operation display panel.

With reference to FIG. 1, the operation of the image forming apparatus main body 1 at the time of normal image forming will be described.
First, the document D is conveyed (fed) from the document table in the direction of the arrow in the drawing by the transfer roller of the document transfer 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, the exposure light L such as a laser beam based on the image information of the electric signal is emitted from the exposure unit 3 toward the photoconductor drum 5 of the image forming unit 4.
In the present embodiment, the image information of the original D is read by the original reading unit 2 while the original D is conveyed by the original conveying unit 10, but the original D is manually placed on the original setting unit of the original reading unit 2. The image information of the manuscript D may be read by placing it.
When the image forming apparatus 1 is used as a printer, the exposure light L is emitted from the exposure unit 3 onto the photoconductor drum 5 based on the image information received from the input device such as a personal computer to the image forming apparatus 1. Will be.

On the other hand, in the image forming unit 4, the photoconductor drum 5 is rotated in the clockwise direction (direction along the conveying direction of the sheet P) in FIG. 1, and a predetermined image forming process (charging step, exposure step, development) is performed. An image (toner image) corresponding to the image information is formed on the photoconductor drum 5 through the process).
After that, the image formed on the photoconductor drum 5 is transferred to the sheet P conveyed by the resist roller pair 17 by the transfer unit 7 as the image forming unit.

On the other hand, the sheet P transported to the transfer unit 7 (image forming unit) operates as follows.
First, one of the plurality of feeding devices 12 and 13 of the image forming apparatus main body 1 is automatically or manually selected (for example, it is assumed that the lower feeding device 13 is selected). .. Then, the uppermost sheet P such as paper stored in the feeding device 13 is fed by the feeding mechanism 52 and transported toward the transport path K. After that, the sheet P passes through the transport path K in which the plurality of transport roller pairs are arranged and reaches the position of the resist roller pair 17. At this time, the resist roller pair 17 is in a state where the rotation is stopped, and the skew of the sheet P is corrected when the tip of the sheet P abuts on the nip.
When the feeding device 16 (manual feed feeding device) installed on the side of the device main body 1 is selected, the sheet placed on the mounting portion (manual feed tray) of the feeding device 16 by the user. P (when a plurality of sheets P are loaded, the uppermost sheet P) is fed by the feeding mechanism 52 toward the transport path and reaches the position of the resist roller pair 17.

Then, the rotation of the resist roller pair 17 is started, and the sheet P after the skew is corrected by the resist roller pair 17 is aligned with the image formed on the photoconductor drum 5. The image is conveyed toward the transfer unit 7 (image forming unit) at the same timing.

Then, the sheet P after the transfer step reaches the fixing device 20 via the transport path after passing through the position of the transfer unit 7. The sheet P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the toner image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22. (It is a fixing process). The sheet P after the fixing step in which the toner image is fixed is sent out from between the fixing roller 21 and the pressure roller 22 (which is a fixing nip), and then discharged from the image forming apparatus main body 1 to output an image. Will be loaded on the discharge tray 31.
In this way, a series of image forming processes is completed.
In the present embodiment, a roller type fixing device 20 using the heating means as a heater is used, but the configuration of the fixing device 20 is not limited to this, for example, a belt type fixing device or a heating means. Can also be used as a fixing device using an electromagnetic induction coil or a resistance heating element.

Next, the sheet transport device 60 according to the present embodiment will be described in detail with reference to FIG. 2 and the like.
The image forming apparatus 1 in the present embodiment is provided with a conveying path K in which the sheet P is conveyed from the feeding devices 12, 13 and 16 toward the discharge tray 31. A plurality of detection sensors 61 to 65 for detecting the sheet P are provided in the transport path K. Then, by detecting the presence / absence of the sheet P, the tip position, the rear end position, etc. by these detection sensors 61 to 65, jam detection (paper jam detection) or a trigger on various control timings can be performed. ing. For example, when the detection sensor 64 installed on the downstream side of the fixing device 20 does not detect the passage of the sheet P even after a lapse of a predetermined time, it is assumed that the sheet P is jammed at that position, and the screen of the operation display panel 100 is displayed. A message to that effect is displayed above.

The detection sensor 63 shown in FIG. 2 is installed in the transport path K from the upstream transport roller pair 18 to the resist roller pair 17, and rotates the upstream transport roller pair 18 triggered by the detection timing of the tip of the sheet P. This is for controlling the timing of stopping. As a result, the resist roller pair 17 that has stopped rotating is bent at the sheet P in a state where the tip is in contact with the resist roller pair 17, the sheet P is skew-corrected, and the transfer timing of the sheet P is adjusted.
Hereinafter, among the plurality of detection sensors 61 to 65, the detection sensor 61 shown in FIG. 2 will be typically described.

With reference to FIG. 2, the sheet transfer device 60 optically displays a transfer path K in which the sheet P is conveyed in a predetermined transfer direction (in the direction of the arrow in the figure) and a sheet P in which the sheet P is conveyed. A detection sensor 63, which detects the target, is provided.
The transport path K is formed by a transport guide plate facing each other with a gap (a gap through which the sheet P is transported). The transport path K shown in FIG. 2 is a substantially horizontal transport path.
The detection sensor 63 is a photosensor including a light emitting element such as a light emitting diode and a light receiving element such as a photodiode. The detection sensor 63 is provided with a detection unit 63a (detection surface) in which the detection light X1 is projected toward the sheet P and the reflected light X2 reflected by the sheet P is received. That is, the detection unit 63a (detection surface) is provided with a light emitting element and a light receiving element, and is capable of irradiating the detection light X1 from the light emitting element and receiving the reflected light X2 by the light receiving element. become. Then, whether or not the sheet P is located at the position of the detection sensor 63 is detected by the sensor output that changes depending on whether or not the reflected light X2 is received by the light receiving element.
As the detection sensor 63, a specular reflection type sensor can be used, or a diffuse reflection type sensor 63 can be used.

Here, as shown in FIG. 2, the detection sensor 63 according to the present embodiment has its detection unit 63a (detection surface) inclined to the downstream side (left side in FIG. 2) in the transport direction. Have been placed.
That is, the angle θ formed by the detection unit 63a and the surface of the sheet P (the surface on which the detection light X1 is projected) is larger than zero and is formed at an acute angle on the downstream side with respect to the detection unit 63a. The detection sensor 63 is installed at an acute angle so as to be performed.
The tilt angle θ of the detection unit 63a is set so as to be within the range of the detection allowable swing width of the detection sensor 63. That is, regardless of whether the detection sensor 63 is a specular reflection type or a diffuse reflection type, the sheet P is irradiated with the detection light X1 and the light receiving element receives the reflected light X2 from the sheet P. The inclination angle θ is set so that

As described above, in the present embodiment, since the detection sensor 63 is arranged so that the detection unit 63a is inclined to the downstream side in the transport direction, the transport path K is set in the transport direction when the sheet P is transported. Along with the airflow generated along the airflow (the airflow indicated by the white arrow in FIG. 2), foreign matter such as paper dust and suspended toner flows and adheres to the detection unit 63a (detection surface) of the detection sensor 63. Is less likely to occur.
Specifically, as shown in FIG. 3A, when the detection sensor 63 is arranged so that the detection unit 63a is substantially parallel to the transport direction, the airflow in the direction of the white arrow generated along the transport direction is combined with the air flow in the direction of the white arrow. Foreign matter such as paper dust and floating toner flows, and the foreign matter (enclosed by a broken line) adheres to the detection unit 63a of the detection sensor 63. Further, as shown in FIG. 3B, if the detection sensor 63 is arranged so that the detection unit 63a is inclined to the upstream side in the transport direction, the detection unit 63a receives such an air flow properly. Therefore, such a defect is further promoted.

On the other hand, in the present embodiment, since the detection sensor 63 is arranged so that the detection unit 63a is inclined to the downstream side in the transport direction, the detection unit 63a is less likely to receive such an air flow, and the detection unit 63a is difficult to receive. Foreign matter is less likely to adhere to 63a. Therefore, foreign matter adheres to the detection unit 63a, the detection accuracy of the sheet P by the detection sensor 63 is lowered, and the problem of erroneously detecting the presence or absence of the sheet P is less likely to occur.
Further, in the present embodiment, it is possible to reduce the problem that foreign matter adheres to the detection unit 63a without providing a device for blowing air to the detection unit 63a of the detection sensor 63, so that the cost of the device can be increased. It is also possible to prevent the increase in size.
In particular, the detection sensor 63 shown in FIG. 2 is arranged so as to be located below the sheet P passing through the transport path K, has a layout in which the detection unit 63a faces upward, and foreign matter adheres to the detection unit 63a. If this happens, the foreign matter is likely to accumulate, and the application of the present invention becomes useful.

<Modification example 1>
FIG. 4 is a diagram showing a main part of the sheet transport device 60 as a modification 1, and is a diagram corresponding to an enlarged portion of FIG. 2 in the present embodiment.
The detection sensor 63 shown in FIG. 4A is of a specular reflection type, and the reflected light X2 that is specularly reflected on the surface of the sheet P is received by the light receiving element. Further, the detection sensor 63 shown in FIG. 4B is of a diffuse reflection type, and the reflected light X3 diffusely reflected on the surface of the sheet P is received by the light receiving element.
As shown in FIG. 4, the sheet transport device 60 in the first modification is provided with a cover member 70 that covers the upper part of the detection unit 63a of the detection sensor 63. In particular, in the first modification, the cover member 70 is attached to the detection sensor 63.
The cover member 70 is a thin sheet-like member having flexibility such as PET (polyethylene terephthalate), and a cover surface 70a extending in a substantially horizontal direction is formed. In particular, the cover member 70 in the first modification is arranged so that its cover surface 70a extends downstream from the upper end of the inclined detection unit 63a. Further, the cover member 70 does not interfere with the projection of the detection light X1 and the reception of the reflected light X2 by the detection unit 63a regardless of whether the detection sensor 63 is of the specular reflection type or the diffuse reflection type. It is arranged like this.
By providing such a cover member 70, even if foreign matter such as paper dust or floating toner falls by its own weight in the direction of the black arrow, most of it is deposited on the cover surface 70a, so that the detection unit 63a is a foreign matter. It is possible to reduce the problem of getting dirty with.
The cover surface 70a of the cover member 70 is preferably formed of an adhesive material such as acrylic, urethane, or silicone. As a result, the foreign matter that has fallen on the cover surface 70a can be adhered and held.

<Modification 2>
FIG. 5 is a diagram showing a main part of the sheet transfer device 60 as the modification 2, and is a diagram corresponding to FIG. 4 in the modification 1.
As shown in FIG. 5, the cover member 70 in the second modification is connected to the end portion (downstream side end portion) of the cover surface 70a and stands up in a direction away from the end portion (obliquely upward). The return surface 70b is formed.
By providing the cover member 70 with the return surface 70b in this way, even if the foreign matter accumulated on the cover surface 70a flows downstream along the air flow in the direction of the white arrow, it is blocked by the return surface 70b. Therefore, it is possible to reduce the problem that the detection unit 63a is contaminated with foreign matter.

<Modification example 3>
FIG. 6 is a diagram showing a main part of the sheet transport device 60 as the modification 3, and is a diagram corresponding to FIG. 4 in the modification 1.
As shown in FIG. 6, a plurality of guide members 70A to 70C are installed in the detection sensor 63 in the modified example 3. Specifically, a plurality of guide members 70A to 70C are installed in a staggered manner in the inclination direction of the detection unit 63a so as not to block the optical path of the detection sensor 63.
By providing the plurality of guide members 70A to 70C in this way, it is possible to reduce the adhesion of foreign matter to the detection unit 63a in a wide range. Further, as shown in FIG. 6, since the plurality of guide members 70A to 70C have short lengths in the transport direction, the detection unit 63a is configured so that the inclination angle with respect to the detection unit 63a can be adjusted separately. The range covering the detection unit 63a can be widened while finely adjusting without interfering with the detection in.

<Modification example 4>
FIG. 7 is a diagram showing a main part of the sheet transport device 60 as the modified example 4, and is a diagram corresponding to FIG. 4 in the modified example 1.
The cover member 70 in the fourth modification is detachably attached (replaceable) to the detection sensor 63. Further, in the modified example 4, the relative inclination angles θ1 and θ2 of the cover member 70 with respect to the detection unit 63a can be adjusted.
Specifically, when a plurality of detection sensors are installed in the transport path K of the image forming apparatus 1, it is desired to use those that are made into common parts as the detection sensors. However, the inclination angle θ of the detection sensor changes depending on the degree of inclination of the opposite transport paths. Then, the cover member 70 wants to be arranged so that the cover surface 70a is substantially horizontal.
From these facts, as shown in FIGS. 7A and 7B, different cover members 70M and 70N can be attached to and detached from different detection sensors 63 (common parts) having inclination angles θ1 and θ2, respectively. are doing. Specifically, the angle adjusting portion 70c that supports the root portion of the first cover member 70M and the angle adjusting portion 70d that supports the root portion of the second cover member 70N are both attached to the side surface of the detection sensor 63. However, they are formed so that their shapes (inclination angles) are different from each other. Then, when the first cover member 70M is attached to the detection sensor 63 arranged so that the inclination angle is θ1, the cover surface 70a becomes substantially horizontal. On the other hand, when the second cover member 70N is attached to the detection sensor 63 arranged so that the inclination angle is θ2 (<θ1), the cover surface 70a becomes substantially horizontal. The angle adjusting portions 70c and 70d are both triangular columnar members made of a resin material.
With this configuration, it is possible to standardize a plurality of detection sensors 61 to 65 installed in the transport path K of the image forming apparatus 1.

<Modification 5>
FIG. 8 is a diagram showing a main part of the sheet transfer device 60 as a modification 5.
In the present embodiment and the modified examples 1 to 4, the detection sensor 63 installed in the transport path K between the resist roller pair 17 and the upstream transport roller pair 18 has been described, but other detections in the image forming apparatus 1 have been described. Naturally, the present invention can be applied to the sensors 61, 62, 64, and 65.
FIG. 8 is a diagram showing a transport path K arranged on the side of the feeding device 13. The present invention can also be applied to the detection sensor 61 installed in the transport path K extending in the vertical direction as shown in FIG. That is, as shown in FIGS. 8A and 8B, the detection sensor 61 is arranged so that the detection unit 61a of the detection sensor 61 is inclined to the downstream side in the transport direction. Further, as shown in FIG. 8B, a cover member 70 having a substantially horizontal cover surface 70a is installed so as to cover the upper part of the detection unit 61a. Further, a return surface 70b (a return surface that stands diagonally upward) is provided so as to be connected to an end portion of the cover surface 70a (the end portion on the side closer to the transport path).
Even in the case of such a configuration, the same effect as that of the present embodiment can be obtained.

As described above, the sheet transfer device 60 according to the present embodiment is a detection sensor that optically detects the transfer path K in which the sheet P is conveyed in the predetermined transfer direction and the sheet P in which the sheet P is conveyed. 63 and are provided. Then, the detection sensor 63 is arranged so that the detection unit 63a, in which the detection light X1 is projected toward the sheet P and the reflected light X2 reflected by the sheet P is received, is inclined to the downstream side in the transport direction. Has been done.
As a result, it is possible to prevent foreign matter from adhering to the detection unit 63a of the detection sensor 63.

In the present embodiment, the present invention is applied to the sheet transfer device 60 installed in the monochrome image forming apparatus 1, but naturally, the sheet conveying device installed in the color image forming apparatus 1 is also applied. The present invention can be applied.
Further, in the present embodiment, the present invention is applied to the sheet transfer device 60 installed in the electrophotographic image forming apparatus 1, but the application of the present invention is not limited to this, and other methods are not limited to this. The present invention can also be applied to a sheet transfer device installed in an image forming apparatus (for example, an inkjet type image forming apparatus, a stencil printing machine, etc.).
Further, in the present embodiment, the present invention is applied to the sheet transport device 60 that transports the sheet P before the image is supported in the image forming apparatus 1, but the image (unfixed image or fixed image). The present invention can be applied to a sheet transporting device that transports a sheet after the image is supported, and the present invention is also applied to a document transporting unit 10 (automatic document transporting device) as a sheet transporting device. can do.
Further, the position and number of the detection sensors installed in the image forming apparatus 1 are not limited to those of the present embodiment.
And even in such a case, the same effect as that of the present embodiment can be obtained.

It is clear that the present invention is not limited to the present embodiment, and the present embodiment can be appropriately modified in addition to the suggestions in the present embodiment within the scope of the technical idea of the present invention. is there. Further, the number, position, shape, etc. of the constituent members are not limited to the present embodiment, and can be a suitable number, position, shape, etc. for carrying out the present invention.

In the specification of the present application and the like, the term "sheet" is defined to include all sheet-shaped recording media such as coated paper, label paper, OHP sheet, metal sheet, film, etc., in addition to paper. To do.

1 Image forming apparatus (image forming apparatus main body),
60 sheet transfer device,
63 Detection sensor (seat detection sensor),
63a detector,
70 cover member,
70a cover surface,
70b return surface,
70c, 70d angle adjustment unit,
P sheet, K transport route,
X1 detection light, X2, X3 reflected light.

Japanese Unexamined Patent Publication No. 2006-151564 Japanese Unexamined Patent Publication No. 2011-105419

Claims (8)

A transport path in which the sheet is transported in a predetermined transport direction, and
A detection sensor that optically detects the sheet transported along the transport path, and
With
The detection sensor is characterized in that a detection unit in which the detection light is projected toward the sheet and the reflected light reflected by the sheet is received is arranged so as to be inclined to the downstream side in the transport direction. Sheet transfer device. The sheet transfer device according to claim 1, wherein the detection sensor is arranged so as to be located below a sheet passing through the transfer path. It is characterized by having a cover surface extending in a substantially horizontal direction, and providing a cover member that covers the upper part of the detection unit without interfering with the projection of the detection light and the reception of the reflected light in the detection unit. The sheet transfer device according to claim 1 or 2. The sheet transport device according to claim 3, wherein the cover member includes a return surface that is connected to an end portion of the cover surface and stands up in a direction away from the end portion. The sheet transport device according to claim 3 or 4, wherein the cover surface is made of an adhesive material. The sheet transport device according to any one of claims 3 to 5, wherein the cover member is detachably installed on the detection sensor. The sheet transport device according to any one of claims 3 to 6, wherein the relative inclination angle of the cover member with respect to the detection unit can be adjusted. An image forming apparatus comprising the sheet conveying apparatus according to any one of claims 1 to 7.

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