JPH11116103A - Sheet setting device, sheet guiding device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably detect sheets with curved parts in both cross directional edges, in a paper feed cassette for image formation, or a sheet setting device of a document loading portion. SOLUTION: The sheet setting device has a setting surface of a setting member 3 on which sheets are set and a pair of side regulation means 2, which regulates the position of both edges of sheets and at least one of which is movable. A reflected light detection type sheet sensor 1 is supported by a support member near at least one of the pair of side regulation means 2 and at the lower portion 2a of the sheet setting surface. The detection light axis of the sheet sensor 1 tilts at a predetermined tilting angle of 90-α deg. towards the sheet setting surface, that is, towards the cross directional center of the sheet. Furthermore, the detection light axis is directed upward towards the sheet setting surface through a detection hole 3 of the sheet setting surface, whereby reflected light from sheets is accurately detected although both edges of the sheets curve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, a copying machine, a facsimile, and the like, and more particularly, to a sheet stacking apparatus in a sheet feeding section in an image forming apparatus and a sheet in a sheet guide apparatus in a document reading section. It relates to improvement of detection of presence or absence of material.

[0002]

2. Description of the Related Art Conventionally, in a copying machine, which is an example of an image forming apparatus, there is a manual sheet feeding section as a sheet material stacking apparatus configured as shown in FIGS. A sheet material loading device for loading a sheet material such as paper includes a lifter plate 30 serving as a sheet material loading member for loading the sheet material.
3 and a pair of side restricting members 302 that can be slid on the lifter plate 303 so that the distance between them can be changed. The lifter plate 303 is placed on a tray main body 306. I have.

[0003] The tray body 306 has a root portion attached to the image forming apparatus body, and is arranged with a gradient such that the height increases as the distance from the attachment portion increases (Fig. 3). Also, in the vicinity of the two side regulating members 302,
A pair of sheet material detection sensors 303 is provided in parallel with the sheet material loading plane of the lifter plate 303, and not only detects the presence or absence of the sheet material 305 on the lifter plate, but also corrects the side regulating member on the sheet material. Detection is performed so that it can be determined whether or not it has been applied.

[0004]

However, in the above conventional example, when the sheet material stacked on the lifter plate is curled, or when the sheet of the side regulating member is partially covered with the sheet material on the tray body. When the end of the sheet material is inclined higher than the surface, the sheet material may be inclined with respect to the sheet material detection sensor, or the distance between the sensor and the sheet material may be increased, thereby causing a detection error. There is.

In particular, when the sheet material is OHP or color paper, or a sheet material having an image on the lower surface in advance when a tray is loaded in order to form an image on both sides, the detection capability of the reflection type photo sensor is higher than that of white paper. As compared with the case, the sheet material detection performance may be reduced if the sheet material is inclined as described above.

[0006] It is considered that the possibility that the detection performance of the sheet material is reduced as described above also occurs when the original sheet is conveyed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is directed to a sheet material stacking device and a sheet material guide device.
Stable by providing a pair of sheet material detection sensors with the detection surface inclined inward, and by locating the distance between the detection sensor and the sheet material loading section above the detection sensor smaller than the optimum detection distance of the sheet material detection sensor It is an object of the present invention to enable detection of the presence or absence of a sheet material.

[0008]

In order to achieve the above object, a sheet material placing apparatus according to the present invention comprises a sheet material placing surface on which a sheet material is placed, and a sheet material placing surface disposed on the sheet material placing surface. And a pair of side restricting means for restricting positions on both sides of the sheet material, wherein at least one of the pair of side restricting means is movable. A reflected light detection type sheet material sensor is provided in the vicinity of at least one of the restricting means and below the sheet material placement surface, and the detection optical axis of the sheet material sensor has a predetermined inclination angle toward the center in the sheet width direction. It is characterized by being inclined and passing above the sheet material mounting surface through a detection hole of the sheet material mounting surface.

The sheet material placing device includes a manual sheet material placing device outside the main body of the image forming apparatus, a sheet material placing device for feeding paper inside the main body of the device, and a sheet material placing sheet for re-feeding of the automatic duplex conveying means. It can be any of a placement device, a deck sheet feeding device, and a document sheet loading device.

A sheet material guide device according to the present invention is a sheet material guide device having a sheet material mounting surface for guiding at least a lower portion of a sheet material to be conveyed, wherein at least one side of a sheet path width orthogonal to a sheet conveying direction is provided. A reflected light detection type sheet material sensor for detecting the passage or position of the sheet material is provided, and a detection optical axis of the sheet material sensor is inclined at a predetermined inclination angle toward the center of the sheet material. And

The sheet material guiding device can guide a sheet material before image formation or a sheet material guide after image formation.

The sheet material sensor has a light emitting portion and a light receiving portion, and can determine the presence or absence of the sheet material based on light reflected from the sheet.

[0013] The inclination angle of the detection optical axis of the sheet material sensor may be 1 ° to 15 °.

The distance between the sheet material sensor and the sheet material mounting surface above the sensor can be made smaller than the optimum detection distance of the sheet material sensor.

The sheet material sensor has a pair of a light-emitting portion and a light-receiving portion disposed in the front and rear directions of the sheet material conveyance direction. The optimal detection position can be determined by crossing upward.

An image forming apparatus according to the present invention includes any one of the above-described sheet material placing apparatuses or sheet material guiding apparatuses, and image forming means for forming an image on a sheet material.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail.

[First Embodiment] FIGS. 1 to 3 show a sheet material stacking apparatus according to a first embodiment of the present invention. FIG. 1 is a schematic cross-sectional view of the vicinity of a sheet material detecting portion. FIG. FIG. 3 is a schematic view of a manual-feed transfer material stacking tray, and FIG. 3 is a schematic view of a copying machine equipped with a transfer material stacking tray.

In FIG. 2, reference numeral 6 denotes a tray body for loading a sheet material such as paper (hereinafter, often referred to as a transfer material). Reference numeral 3 denotes a rotating shaft on one side, and paper is fed around the rotating shaft. The lifter plates 2a and 2b, which are sheet stacking units that move up and down so that the height of the sheet material at the position becomes constant, slide on the lifter plate 3 in a direction perpendicular to the sheet material conveyance direction to slide the sheet. It is a side regulating plate that regulates the side. Further, the side regulating plates 2a and 2b can change their intervals according to various paper sizes by sliding in conjunction with each other. 3a indicates a hole through which the optical axis passes.

Next, in FIG. 1, reference numeral 1 denotes a reflected light detection type photosensor, which is provided one by one in the vicinity of each side regulating plate 2 so as to interlock with, for example, the side regulating plate. Support member 2 disposed below the
a. In this embodiment, the optical axis of the photosensor is α ° from the surface perpendicular to the mounting surface of the transfer material 5 which is a sheet material on the lifter plate toward the center in the width direction of the transfer material 5.
At an angle. Therefore, the optical axis is inclined by (90-α) ° with respect to the transfer material mounting surface. In the present embodiment, the inclination angle α ° is about 5 °. Further, the mounting height of one sensor is such that the upper surface of the sensor is located at a distance L1 mm below the mounting surface of the lifter plate on which the transfer material is placed. The distance L1 mm is about 5 mm in the present embodiment.

Here, the reflected light detection type photosensor 1 used in the present embodiment will be described. In FIG. 4, reference numeral 31 denotes a light emitting portion, and the light emitting portion comprises an infrared light emitting diode (not shown) and a lens. Reference numeral 32 denotes a light receiving unit which is constituted by a photodiode and a lens (not shown). The light emitting unit and the light receiving unit are disposed before and after when viewed in the sheet material, ie, transfer material transport direction.

Since the beam of the sensor 1 has a certain size, the positional relationship with the object is not a pinpoint. However, the sensor 1 particularly has an effect on the detection distance or the relative inclination with respect to the object. The detection distance is a detection distance L2 from the upper surface of the sensor 1 to the object to be detected, and the relative inclination is when the angle difference between the sensor upper surface and the detection surface is 0 °. Is the optimal value. The detection distance L
2 is about 8 mm in the present embodiment, and each optical axis of the light emitting unit 31 and the light receiving unit 32 is determined by the included angle β between the lifter plate and the transfer material surface.

The sensor 1 determines the presence or absence of an object to be detected in the sensor. When the current value from the above-mentioned light-receiving diode exceeds a certain threshold value, the TTL signal indicates Hi. Otherwise, a Low signal is issued to its output terminal. Therefore, the sensor 1 has GND and + 5V,
And three TTL output signal lines, and a total of three power supply lines and signal lines.

Next, the features of the copying machine according to the present invention will be described with reference to FIG.

In FIG. 3, the transfer material loading tray 6 of the present embodiment is provided on the right end side of the printer unit 102 of the copying machine main body, and is attached to the printer at the root of the tray main body 6, and is separated from the mounting part. Are arranged with a gradient that becomes higher as follows. Reference numeral 10 denotes a transfer material automatic feeding cassette, which has a higher curvature of the path to the image forming unit of the printer 102 than the automatic feeding unit related to the manual feeder transfer tray 6, so that a special paper such as an OHP sheet or cardboard is used. Not suitable for transfer material transfer. Therefore, a manual feed portion is used for such a special transfer material.

Here, a case of handling the copying machine shown in FIG. 3 according to the present embodiment will be described. A laser beam modulated based on image information input from the document scanner unit 101 via the controller 71 is transmitted to the laser unit 72.
The beam is applied to a photosensitive drum 73 as an image carrier via a reflection mirror 70, and an electrostatic latent image is formed on the drum by an electrophotographic method. The surface of the photosensitive drum is uniformly charged by the primary charging means 75 before the latent image is formed.

The latent image is developed by a toner 74 as a developer. On the other hand, the transfer material 15 stacked on the middle plate 13 of the paper feed cassette 10
1. The transfer material is sent to a stopped registration roller pair 53 by a roller 62 which is a conveying means, and the transfer material is skewed there. The registration roller sends the transfer material to the transfer section with the timing of aligning the tip position of the toner image on the photosensitive drum with the tip of the transfer material, and the transfer unit 78 transfers the toner image on the photosensitive drum to the transfer material.

After the transfer, the transfer material is conveyed to a fixing unit 80 by a conveying means 79, and the toner image is heated and fused to the transfer material. Thereafter, the transfer material is discharged to a discharge tray 81. The toner remaining on the photosensitive drum after the transfer is cleaned by a cleaning unit 77, and the toner is collected.

In the case of manual sheet feeding, the transfer material on the lifter plate 3 is fed and conveyed toward the registration roller pair 53 by the sheet feeding roller 51 and the conveying roller 52 in the same manner as described above.

In the case of manual paper feed, when the operator places the transfer material on the transfer material loading tray 6 and moves the side regulation plate 2 to the paper width, the sensor 1 recognizes the transfer material on the tray and detects 71. The signal is sent to the printer controller, and the transfer material can be fed from the manual feed portion, and is displayed on an operator operation unit provided on the side of the document scanner 101 (not shown).

If the side regulating plate is not slid to a position where it abuts the transfer material on both sides, at least one of the sensors 1 cannot recognize the transfer material and sends a signal to the printer controller to send the signal to the printer controller. As described above, the controller causes the operation unit to display that the transfer material cannot be fed from the manual feed unit.

When the transfer material 5 is placed on the manual feed tray in the form shown in FIG. 1, the transfer material can be detected stably because the optical axis of the sensor is tilted in advance. At the same time, the optimum position for detection by the sensor 1 is previously set higher than the transfer material loading surface, so that even if the transfer material floats at the detection position, it can be detected stably.

By the way, in the copying machine using the present embodiment, when the transfer material curls on the manual feed tray, the amount of the transfer material curling downward as shown in FIG. In addition, it can be said that most of them have such a tendency. In a copying machine use environment, the largest warpage of the transfer material occurs in a low humidity environment of less than 10% humidity. In this environment, the transfer material on the manual feed tray is 10 ° relative to the sensor at the sheet material detection unit. °, floating up to 5 mm from the original loading surface may occur.

In some cases, contrary to FIG. 1, a transfer material that is convex upward may be placed. In this case, in the transfer material detection unit, the detection distance does not change from the nominal position. Furthermore, the amount of inclination to the opposite side is particularly small, and there is little influence on the present embodiment.

[Embodiment 2] FIGS. 5 and 6 show a second preferred embodiment of the present invention.

FIG. 5 is a sectional view of a document stacking tray including a document stacking detection section of an automatic document feeder according to a second embodiment of the present invention, and FIG. 6 is provided with the automatic document feeder. FIG. 2 is a schematic diagram of a document scanner.

In FIG. 5, reference numeral 22 denotes a document stacking tray 29.
Reference numeral 21 denotes a reflected light detection type photosensor similar to that used in the first embodiment, and a detection hole 29a provided in the document side restriction portion and the document stacking tray. Below, it is fixed so that it is always equidistant from the document stacking tray.

In the present embodiment, the sensor 21 is tilted by γ ° from the side regulating portion 22 toward the center with respect to the loading surface of the document as the sheet material. In the present embodiment, the angle γ is about 3 °, and therefore, it is inclined at an angle of about 87 ° toward the center of the document sheet in the width direction with respect to the document placing surface. Reference numeral 23 denotes a slide type other document side regulating portion, which includes an elastic member 26, a pressing plate 27, and a set screw 28.
Thus, the document stacking tray 29 is slidably attached to the original stacking tray 29 without play.

Here, a case where the operator actually handles the document scanner of FIG. 6 according to the present embodiment will be described. When the operator places a document on the document stacking tray 222 and moves the side regulating plate 22 to the paper width, the sensor 21 recognizes the document on the tray and sends a signal to the controller 216 to send the signal to the controller 216. That the original is loaded on the original reading unit 201 is displayed on an operator operation unit provided in the original reading unit 201 (not shown).

If the side regulating plate is not slid to the position where the document abuts, the sensor 21 cannot recognize the document and sends a signal to the controller 216, and the controller sends the signal to the operation unit in the same manner as described above. Indicates that no original is loaded. Here, when the document 25 is placed on the document loading tray in the form shown in FIG. 5, the optical axis of the sensor is tilted in advance, so that the document can be detected stably. At the same time, since the sensor 21 is previously disposed higher than the transfer material loading surface, even if the transfer material floats at the detection position, the detection can be performed stably.

Next, when the operator turns on the document reading start switch of the operator operation section in a state where the document is correctly set, the automatic document feeder operates the document loading tray 22.
2 is separated by a half-moon roller 223 and a separation belt 224 and a paper feed roller 225 and taken into an automatic document feeder. Platen glass 2
It is conveyed to a predetermined position on 17 and positioned.

A first carriage having a document illuminating means 211 and a reflection mirror 212 in a document reading section;
The second carriage having the two reflection mirrors 213 and 214 is moved along the original on the platen glass, and the reflected light of the original is converted into an analog electric signal by the lens 215 = CCD unit. Digital image data is created by the D conversion means and stored in a frame memory in the controller. Then, the document whose image data has been read is returned to the top of the document stacking tray again, and the above sequence is repeated until the image reading of the document stacked on the tray is completed.

As described above, in the second embodiment, similarly to the first embodiment, even if the sheet material of the object to be detected is inclined by the sheet material detecting section as shown in FIG. The presence or absence can be determined. Further, in the automatic document feeder as shown in FIG. 6, the ratio of handling the image output on the original stacking tray with the image side up and the image output from the image forming apparatus as the original is high. Since the toner or the like forming the image contracts with time and the sheet material tends to curl on the image surface side, the document is frequently placed on the document stacking tray in a convex state as shown in FIG. ,
The effect of the embodiment of the present invention is great.

[Embodiment 3] FIG. 7 is a schematic sectional view of a transfer material transporting posture detecting section of a printer section of a copying machine showing a third embodiment of the present invention, and FIG. 8 is a third embodiment of the present invention. 1 is a schematic view of a copier equipped with a.

In FIG. 7, reference numeral 19 denotes a reflected light detection type sheet material detection sensor, which is the same as that of the first embodiment, and is disposed at a position corresponding to both the back and front sides of the transferred transfer material in FIG. As shown in the figure, the support member 16 attached to the back side of the lower guide 18 of the sheet conveying section by burring caulking has an angle of δ ° toward the center in the width direction of the transfer material as shown in FIG. L from the upper surface of the lower guide 18
It is fixed at a position 3 mm below. In the present embodiment, the angle δ is about 4 °, and L3 is about 6 mm.

Next, the features of the copying machine according to the present invention will be described from the point at which the printer unit 102 of the copying machine feeds the transfer material from the manual feed unit 6, forms an image, and outputs.

In FIG. 8, the transfer material 5 of the manual paper feed unit 6
Is fed by a sheet feeding roller 51 and a known sheet material retard roller pair 52, and is sent at a predetermined timing by a registration roller pair 53. Here, the transfer material that has exited the registration roller pair 53 passes through the detection units of the two sheet material detection sensors 19 in the front and the back according to the third embodiment of the present invention. At the detection timing of the sensor, the printer controller 71 recognizes the timing and posture of the transfer material entering the image forming unit.

However, the manual paper feed unit of the copier equipped with the third embodiment of the present embodiment has a cassette paper feed unit 10.
In contrast to this, since it is possible to feed OHP sheets and transfer materials of a wide range of materials without limitation such as blank paper having a basis weight in the range of 64 to 100 g, those which make the detection capability of the sensor 19 difficult are fed from manual feed. Transfer material is included.

Since the transfer material sent from the manual sheet feeding section has a curl tendency that is convex downward as in the first embodiment, the sensor 19 can be stably detected by disposing the sensor 19 as shown in FIG. It has become. Here, the transfer material conveyed from the manual feed portion to the sensor 19 has a maximum inclination of 8 ° with respect to the sensor at the sheet material detection sensor portion and a maximum lift amount of 3 mm with respect to the sensor. It is. By the detection by the sensor as described above, it is possible to prevent the image forming defect on the transfer material due to the skew of the transfer material 5 as shown in FIG.

In FIG. 8, the formation, development, fixing and the like of the latent image on the photosensitive drum are performed as described in the first embodiment.

[Other Embodiments] In the above-described first to third embodiments, the transfer material manual feed section, the transport section before image transfer, and the document stacking section are particularly shown, but the present invention is not limited to these. However, the present invention is also applicable to a sheet cassette that can be stored in the main body, a sheet re-feeding cassette of automatic double-sided conveying means, a deck sheet feeding device, or a sheet position detection sensor after image formation on a sheet material conveying path. Where the same effect as the effect can be obtained, it can be effectively implemented.

In the first to third embodiments, the range of the amount of warpage of the transfer material or the original to be used and the inclination angle of the optical axis of the sensor toward the center of the transfer material or the original in the width direction are exemplified in each embodiment. However, the range to which the present invention can be applied is not limited to these ranges, and the inclination angle of the optical axis can be set to 75 to 89 °, and is used in the copying machine and the automatic document feeder of the above embodiment. Some transfer materials that cannot be used are inclined at a maximum of 30 ° at a position corresponding to the detection portion of the sheet material, but the sheet material detection means of the present invention is effective for detecting such a sheet material and can be effectively implemented.

[0053]

As described above, according to the present invention,
A sheet material detection sensor with the detection optical axis tilted toward the center of the sheet material placement part is provided, and the distance between the detection sensor and the sheet material loading part above the detection sensor is smaller than the optimum detection distance of the sheet material detection sensor. By doing so, it is possible to perform stable detection even on an OHP sheet or the like that is inclined on both sides as viewed in the transport direction, which was previously unstable in detectability.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a manual feed tray unit of a copying machine according to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view of a manual feed tray unit of the copying machine according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram of a copying machine according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram of a reflected light detection type sheet material detection sensor according to the first embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a document stacking tray of the automatic document feeder according to the second embodiment of the present invention.

FIG. 6 is a schematic diagram of a document scanner provided with an automatic document feeder according to a second embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of a transfer material posture detection unit of a copying machine according to a third embodiment of the present invention.

FIG. 8 is a schematic diagram of a copying machine according to a third embodiment of the present invention.

FIG. 9 is a diagram illustrating a relationship between a posture of a transfer material and laser writing according to a third embodiment of the present invention.

FIG. 10 is a schematic diagram of a manual feed tray of a copying machine showing a conventional example.

FIG. 11 is a sectional view of a manual feed tray of a copying machine showing a conventional example.

[Explanation of symbols]

 1, 19, 21, 31 ... sheet material detection sensor 2, 23, 302 ... slide type sheet material side regulating plate 3, 303 ... lifter plate 5, 305 ... transfer material 6,306 ... transfer material loading tray body 16 ... sheet material Detection sensor mounting member 17 Transfer material transport upper guide 18 Transfer material transport lower guide 20 Automatic document feeder 22 Fixed side regulating portion 25 Document 31 Light emitting portion 32 Light receiving portion 70 Laser reflecting mirror 71 Printer Controller 72: Laser scanning optical system 73: Photosensitive drum 101: Original scanner 102: Printer

Claims (9)

[Claims] 1. A sheet material mounting surface on which a sheet material is mounted,
A pair of side restricting means disposed on the sheet material mounting surface for restricting positions on both sides of the sheet material, wherein at least one of the pair of side restricting means is movable. In the placing device, a reflected light detection type sheet material sensor is provided near at least one of the pair of side regulating means and below the sheet material placing surface, and a detection optical axis of the sheet material sensor is a sheet width. A sheet material placing apparatus which is inclined toward the center in the direction at a predetermined inclination angle, and is directed upward above the sheet material placing surface through a detection hole in the sheet material placing surface. 2. The sheet material placing device according to claim 1, wherein the sheet material placing device is a manual sheet material placing device outside the image forming apparatus main body, a sheet material placing device inside the apparatus main body, and an automatic double-sided conveying means. A sheet material placing device, which is one of a sheet material placing device for re-feeding, a sheet material placing device for deck feeding, and an original sheet material placing device. 3. A sheet material guide device having a sheet material placement surface for guiding at least a lower portion of a sheet material to be conveyed, wherein at least one side of a sheet path width orthogonal to the sheet conveyance direction passes or positions the sheet material. A sheet light sensor of a reflected light detection type for detecting a sheet material, wherein a detection optical axis of the sheet material sensor is inclined at a predetermined inclination angle toward the center of the sheet material. 4. The sheet material guide device according to claim 3, wherein the sheet material guide device performs sheet material guide before image formation or sheet material guide after image formation. 5. The sheet material according to claim 1, wherein the sheet material sensor has a light emitting portion and a light receiving portion, and determines presence or absence of the sheet material based on light reflected from the sheet. Mounting device. 6. The sheet material sensor according to claim 1, wherein a tilt angle of a detection optical axis of the sheet material sensor is 1 ° to 15 °.
° the sheet material placing apparatus. 7. A sheet material mounting apparatus according to claim 1, wherein a distance between the sheet material sensor and a sheet material mounting surface above the sensor is smaller than an optimum detection distance of the sheet material sensor. Device. 8. The sheet material sensor according to claim 1, wherein the sheet material sensor includes a pair of a light emitting unit and a light receiving unit disposed in front and rear of the sheet material in the sheet conveying direction, and the optical axis of the light emitting unit and the light receiving unit. A sheet material placing apparatus which is inclined with respect to the placing surface and intersects above the sheet material placing surface to determine an optimum detection position. 9. An image forming apparatus, comprising: the sheet material placing device or the sheet material guiding device according to claim 1; and an image forming means for forming an image on the sheet material.