JP2002154695A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a paper detecting mechanism by reducing the number of part items of the paper detecting mechanism of an image forming device. SOLUTION: A first actuator 84 for contacting with paper of a carrying passage 65 is arranged in an upper side guide member 58 for guiding the paper P carried from the paper tray side to a regist roller 30, and a second actuator 86 for contacting with the paper of a carrying passage 69 is arranged. A light sensor 88 capable of detecting a movement of the second actuator 86 is arranged on a body frame side fixed guide surface 68. Here, by arranging a synchronous means (a projection 84B, a torsion spring 85, a projection 86A, and a torsion spring 87) for rotating the second actuator 86 together with the first actuator 84, the light sensor 88 results in one.

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 for recording an image on a sheet-like recording medium such as a sheet cut to a predetermined size by an image forming section.

[0002]

2. Description of the Related Art Various types of image forming apparatuses such as a printer, a facsimile, and the like are used, such as an electrophotographic type, an ink jet type, and a thermal transfer type. An image such as a character or a drawing is formed by an image forming unit on a sheet-shaped recording medium such as a sheet of paper cut into pieces.

[0003] For example, in an ink jet system or a thermal transfer system, an image is formed on a sheet or the like based on a digital signal.

In an electrophotographic system or an electrostatic recording system, an image is formed by applying toner to an electrostatic latent image on an image carrier, and this toner image is transferred and fixed on paper or the like. You.

[0005] Sheets or the like to which an image is applied as described above are generally stacked and stored in a sheet feeder provided in the image forming apparatus, and are sequentially supplied one by one from here.

The paper and the like stored in the paper feeder need to be appropriately replenished, and a paper tray which is a cassette detachable from the apparatus main body is used so that the reinforcement can be easily performed. The paper tray is supplied with paper and the like, and stored.

[0007] Such paper trays are sometimes provided with only one in one image forming apparatus. However, in order to select images of different sizes and to give an image, for example,
2. Description of the Related Art There is an image forming apparatus provided with a manual feed tray that is convenient for arbitrarily using various sizes and various types of paper, and a cassette type paper tray that mounts paper of a predetermined size.

This image forming apparatus is provided with a feed roll for transporting the paper from the manual feed tray and the paper from the cassette type paper tray to the image forming section.

Further, a paper transport path for guiding the paper in the manual feed tray to the feed roll and a paper transport path for guiding the paper in the cassette type paper tray to the feed roll are provided. Necessary to rotate the feed roll at a predetermined timing,
A paper detection mechanism is provided.

The sheet detecting mechanism has an actuator which rotates and displaces by contacting the sheet, a sensor for detecting the rotation of the actuator, a spring for returning the actuator to a fixed position, and the like.

[0011]

However, the above-described image forming apparatus has the following problems. Since there are two paper transport paths, each of which uses an actuator and a sensor, two actuators and two sensors are provided as a whole apparatus, which increases the number of parts and increases the size of the paper detection mechanism. was there.

Also, as a second problem, there is a case where the paper which has passed over the actuator is lifted by the reaction force of the actuator so that the leading end is in a wavy state, and enters the feed roll as it is, causing wrinkles on the paper. .

The invention according to the present application has been made in view of the above circumstances, and a first object is to reduce the number of parts of the paper detection mechanism to reduce the size of the paper detection mechanism. A second object is to prevent paper from waving.

[0014]

According to a first aspect of the present invention, there is provided an image forming section for forming an image on a sheet, a registration roll for conveying the sheet to the image forming section, and a sheet fed from a first sheet tray. A first conveyance path for guiding the sheet fed to the registration roll, a second conveyance path for guiding the sheet sent from the second sheet tray toward the registration roll, and the first conveyance path. The first actuator, which is rotationally displaced from the first position to the second position when the paper conveyed inside the sheet abuts, and the first actuator that is conveyed in the second conveyance path, contacts the first actuator. A second actuator that is rotationally displaced from the first position to the second position, a sensor that detects that the first actuator is rotationally displaced to the second position, and a second actuator that is rotationally displaced to the second position. When rotational displacement, is characterized by having a synchronizing means for rotationally displacing said first actuator in synchronization with the second actuator to the second position.

Next, the operation of the image forming apparatus according to the first aspect will be described.

First, the sheet sent from the first sheet tray is guided to a registration roll on a first transport path. Then, the registration roll conveys the sheet sent from the first sheet tray to the image forming unit. In the image forming unit, an image is formed on the sheet sent from the first sheet tray.

Further, the sheet fed from the second sheet tray is guided toward a registration roll on a second transport path. Then, the registration roll conveys the sheet sent from the second sheet tray to the image forming unit. In the image forming section, an image is formed on the sheet sent from the second sheet tray.

Here, when the sheet is transported in the first transport path, the sheet comes into contact with the first actuator, and the first actuator is rotationally displaced from the first position to the second position.

When the first actuator is rotationally displaced to the second position, this is detected by the sensor, so that the rotation start timing of the registration roll can be determined based on the sheet detection result of the sensor.

When the second actuator is rotationally displaced to the second position, the first actuator is rotationally displaced to the second position in synchronization with the second actuator by the synchronization means. Therefore, the sensor can detect that the second actuator has been rotationally displaced to the second position. Therefore, only one sensor is required.

Here, the first position is a position in a stationary state where the actuator is not operated, and the second position is a position other than the first position.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the first actuator and the second actuator rotate around one rotation axis. .

Next, the operation of the image forming apparatus will be described.

In the image forming apparatus according to the second aspect, the first
Since the first actuator and the second actuator are rotated around one rotation axis, the size of the paper detection mechanism is smaller than when the first actuator and the second actuator are rotated around separate rotation axes. it can.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the image forming apparatus is provided between the first transport path and the second transport path, and is provided between the first transport path and the second transport path. And a guide member that forms at least a part of the second transfer path and forms at least a part of the second transfer path, wherein the first actuator, the second actuator, and the synchronization unit are provided on the guide member, The sensor is provided on a member different from the guide member.

Next, the operation of the image forming apparatus according to the third aspect will be described.

Since the first actuator, the second actuator, and the synchronizing means are provided on the guide member and the sensor is provided on a member different from the guide member, for example, the guide member is provided for removing a sheet having a conveyance failure. Is moved, only the mechanical parts such as the first actuator, the second actuator and the synchronizing means are moved, and a guide member fixedly provided with a sensor connected with wiring on the apparatus body side. To prevent the occurrence of troubles in the electric system.

According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, at least one of the first actuator and the second actuator comprises: When in the first position, when viewed from the sheet width direction orthogonal to the sheet conveyance direction, the sheet contact surface on the upstream side in the sheet conveyance direction is the sheet conveyance on the upstream side in the sheet conveyance direction with respect to the sheet contact surface. It is characterized in that it is set at approximately 90 ° to the direction.

Next, the operation of the image forming apparatus according to the fourth aspect will be described.

For example, when the first actuator is at the first position, the sheet contact surface on the upstream side in the sheet conveying direction when viewed from the sheet width direction orthogonal to the sheet conveying direction is the same as the sheet contact surface. Approx. 9 with respect to the paper transport direction on the upstream side in the paper transport direction
If the angle is set to 0 °, the leading edge of the paper conveyed from the paper tray side abuts at approximately 90 ° to the paper abutting surface. The vicinity can be prevented from being curved. The second
The same applies to the actuator of (1).

The angle of about 90 ° is an angle at which the vicinity of the leading end of the sheet does not bend, and the range varies depending on the type of sheet and the transport speed.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the sheet contact surface when in the first position is viewed from a sheet width direction orthogonal to a sheet conveying direction. In this case, the angle of the sheet contact surface with respect to the sheet conveying direction on the upstream side in the sheet conveying direction when the sheet comes in contact with the sheet gradually decreases as the distance from the rotation axis increases.

Next, the operation of the image forming apparatus according to the fifth aspect will be described.

For example, when a sheet comes into contact with the first actuator, the first first actuator rotates so as to fall in the sheet conveyance direction along with the conveyance of the sheet, and the contact position of the leading end of the sheet gradually increases. It moves to the tip end of the first actuator, but on the sheet contact surface when in the first position,
Since the angle of the paper contact surface with respect to the paper transport direction on the upstream side in the paper transport direction when viewed from the paper width direction orthogonal to the paper transport direction is gradually reduced as the distance from the rotation axis, the leading edge of the paper is Even if the contact position moves to the leading end side of the first actuator, a decrease in the angle formed between the leading end portion of the sheet and the sheet contact surface is suppressed, and the occurrence of the curvature near the leading end of the conveyed sheet can be further suppressed. .

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an image forming apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 2, the image forming apparatus 10
Is an image carrier (a so-called photosensitive drum) 12 on which an electrostatic latent image is formed by irradiating image light after uniformly charged, and a charging device for uniformly charging the surface of the image carrier 12 A device 14; an image writing device 16 for irradiating the image carrier 12 with bright light based on image data to form a latent image based on a difference in electrostatic potential; and selectively transferring toner to the latent image for visualization. A developing device 18; a transfer device 22 for transferring a toner image on the surface of the image carrier to a recording sheet supplied along a sheet transport path 20; 24, and a cleaning 26 for cleaning the toner remaining on the image carrier after the transfer of the toner image.

The image forming apparatus 10 is covered with a main body side cover 10B and a top plate 10A.

Here, the image carrier 12, the charging device 14, the developing device 18 and the cleaning unit 26 form one developing unit 27 by opening the top plate 10A of the image forming apparatus 10 to form a main body frame (see FIG. (Not shown).

It should be noted that the top plate 10A is
The interior is opened by rotating in the direction of the arrow CCW in FIG. 2 with the shaft 10C provided at the upper corner of the arrow B in the direction of the arrow B as a fulcrum.

In the lower part of the image forming apparatus 10,
Paper feeder 2 that stores recording paper and sends it out one by one
8 and a registration roll 30 that conveys the recording paper sent from the paper feeding device 28 to a toner image transfer position at a predetermined timing.

The image carrier 12 has a photoreceptor layer on the back surface, and the potential of the exposed portion is attenuated by exposure after being uniformly charged.

The charging device 14 is a roll-shaped member which is brought into contact with the image carrier 12, and when a voltage is applied between them, a discharge is generated in a minute gap near the contact portion. The surface of the image carrier 12 is charged almost in a similar manner.

As the charging device, in addition to those described above, a charging device that applies a high voltage to the electrode wires and charges the image carrier by corona discharge can be used.

The image writing device 16 scans the peripheral surface of the image carrier 12 with a blinking laser beam, and forms an electrostatic latent image on the peripheral surface of the image carrier 12 based on image data.

The post-writing device may be one in which light-emitting elements such as LEDs are arranged, and these are turned on and off based on image data.

The developing device 18 includes a cylindrical developing roller 18 disposed so as to be close to and opposed to the image carrier 12.
A, and a developing bias voltage is applied between the developing roller 18A and the image carrier 12.

As a result, a developing bias electric field is formed between the developing roller 18A and the image carrier 12, and the charged toner is transferred to an exposed portion on the image carrier 12 to form a visible image. It is.

The transfer device 22 is a roll-shaped member provided so as to face the image carrier 12, and forms a transfer electric field between the transfer device 22 and the image carrier 12 so that the transfer device 22 is placed on a recording sheet passing therethrough. This is to transfer the toner image. (Paper Feeder) The paper feeder 28 is provided with a first paper tray 34.
A second paper tray 36 disposed below the first paper tray 34, a first paper feed roll 38 for feeding paper from the upper paper tray 34, and a lower paper tray 36.
A second paper feed roll 40 for feeding the paper from the first paper feed roll 38, a first separating member 42 pressed against the first paper feed roll 38,
A second separating member 44 pressed against the paper feed roll 40,
It has a holder 46 rotatably attached to the paper tray 34 and supporting the first separating member 42, and a holder 48 rotatably mounted on the paper tray 36 and supporting the second separating member 44. .

The paper tray 36 disposed on the lower side is detachable from the main body frame of the image forming apparatus 10 as a cassette, and can be pulled out in a direction (arrow F direction) opposite to the direction in which the paper is fed. it can.

The upper paper tray 34 is a manual tray, and paper of an arbitrary size can be easily inserted and used through an opening 49 provided on the side of the image forming apparatus 10 in the direction of arrow F. Is possible.

The first paper feed roll 38 is a half-moon roll with a part of the peripheral surface cut out, and the peripheral surface thereof is brought into contact with the upper surface of the uppermost sheet stacked on the paper tray 34 by being driven to rotate. The uppermost sheet P is sequentially fed out.

The first separating member 42 is supported by a holder 46 rotatably mounted on the paper tray 34, and is urged toward the first paper supply roll 38 by an elastic member such as a spring. I have.

The shaft 50 of the first paper feed roll 38
Is supported so that the core roll 52 can freely rotate.

The first separating member 42 always has the core roll 5
2, when the paper P sent out by the first paper feed roll 38 is conveyed by the registration roll 30, the lower paper P that is loaded follows the upper paper P. To prevent

The second separating member 44 is supported by a holder 48 rotatably mounted on the paper tray 36, and is urged toward the second paper supply roll 40 by an elastic member such as a spring. I have.

A core roll 56 similar to the shaft 50 of the first paper feed roll 38 is provided on the shaft 54 of the second paper feed roll 40.

The second separating member 44 always has the core roll 5
6, when the sheet P sent out by the second sheet supply roll 40 is conveyed by the registration roll 30, the stacked lower sheet P follows the upper sheet P. To prevent

The first paper supply roll 38 is provided on the paper tray 34.
And is provided at a position where the sheet P accommodated in the sheet tray 34 can come into contact therewith. The first paper feed roll 38 is rotated by a motor (not shown) controlled by a control device 89 described later.

The second paper supply roll 40 is provided above the end of the paper tray 36 on the inner side of the apparatus (in the direction of the arrow B), and the paper P accommodated in the paper tray 36 comes into contact therewith. It is provided in a possible position. Second paper feed roll 40
Is rotated by a motor (not shown) controlled by a control device 89 described later.

As shown in FIG. 3, the first paper feed roll 38
On the side of the arrow B, a resist roll 30 composed of a roll 30A arranged on the side of the arrow B and a roll 30B arranged on the side of the arrow F and pressed against the roll 30A.
Are arranged.

The roll 30A and the roll 30B
Is rotated by a motor (not shown) controlled by a control device 89 described later.

The second paper feed roll 40 is disposed between the first paper feed roll 38 and the registration roll 30.

Here, a first tangent line L1 passing through a separation portion (contact portion) between the first paper supply roll 38 and the first separation member 42 is provided.
The nip point between the roll 30A and the roll 30B of the registration roll 30 is disposed between the second paper feed roll 40 and a second tangent L2 passing through a separation portion (contact portion) between the second separation member 44. Although it is preferable that the first tangent L1 be slightly protruded.

In this embodiment, the resist roll 30 is
It is arranged below a horizontal line L3 passing through the upper end of the first paper feed roll 38.

The second paper feed roll 40 is disposed between the first paper feed roll 38 and the registration roll 30 in the horizontal direction.

By keeping the first paper feed roll 38, the second paper feed roll 40, and the registration roll 30 as close as possible while maintaining the above positional relationship,
A rational arrangement in which the height dimension (dimensions in the directions of the arrows U and D) and the depth dimension (dimensions in the directions of the arrow F and the arrow B) of the sheet feeding device 28 are minimized becomes possible.

In this embodiment, the resist roll 3
The distance from the nip point of the rolls 30A and 30B to the nip point of the second paper feed roll 40 and the second separating member 44 is determined by the roll 30A of the registration roll 30 and the roll 3
The distance from the nip point of 0B to the nip point of the first sheet supply roll 38 and the first separating member 42 is set to be smaller.

As shown in FIGS. 1 and 4, the resist roll 3
An upper guide assembly 58 is rotatably and detachably attached via a ring 57 to a shaft 30Ba of the zero roll 30B.

A substantially C-shaped bearing 5 is provided on both sides of the upper guide assembly 58 in the sheet width direction (in FIG. 1, the front and back sides of the sheet).
The upper guide assembly 58 is detachable from the shaft 30Ba by elastically deforming the bearing 59.

The upper guide assembly 58 includes a guide surface 60 for guiding the lower surface of the sheet P sent out from the first sheet supply roll 38 (at the time of stacking), and a sheet sent out from the first sheet supply roll 38. A guide surface 62 that guides the upper surface side of P (at the time of stacking) and a guide surface 64 that guides the upper surface side (at the time of stacking) of the paper P sent from the second paper feed roll 40 are provided.

FIGS. 1 and 4 show the upper guide assembly 58 of the image forming apparatus 10 in a normal state.

As shown in FIG. 1, the guide surface 60 is
A linear portion 60A formed on the paper feed roll 38 side and having a substantially linear cross-sectional shape along the paper transport direction, and a cross-sectional shape formed on the resist roll 30 side of the linear portion 60A along the paper transport direction. First arc portion 6 formed in a convex arc shape
0B, and a second arc portion 60C formed on the registration roll 30 side of the first arc portion 60B and having a concave arc shape in cross section along the sheet transport direction.

On the other hand, the guide surface 62 is provided so as to face the guide surface 60, and is located at a position substantially facing the part of the linear portion 60A of the guide surface 60 and the first arc portion 60B in the sheet transport direction. Upper plane portion 62 having a substantially straight cross section
The upper flat portion 62A is provided with an arc portion 62B on the side of the registration roll 30 facing the second arc portion 60C, the arc portion 62B having a cross-sectional shape along the sheet conveyance direction formed in a convex arc shape at a position facing the second arc portion 60C. I have.

The distance between the guide surface 60 and the guide surface 62 gradually decreases toward the registration roll 30, and the sheet P conveyed by the first feed roll 38 is directed toward the registration roll 30. It is a conveyance path 65 for guiding.

The upper guide assembly 58 has a small-diameter roller 66 rotatably provided at the lower end of the guide surface 64. The rollers 66 rotate when they come into contact with the paper P being conveyed.

A toner sensor (magnetic sensor) 90 that can detect the presence or absence of toner in the developing device 18 provided in the developing unit 27 is mounted above the upper guide assembly 58.

Next, as shown in FIG.
A fixed guide surface 68 is provided on the side of the main frame 0 on the side of arrow B of the upper guide assembly 58.

The fixed guide surface 68 has a substantially vertical vertical surface 68A provided at a position facing the guide surface 64, and an inclined portion 68B extending diagonally upward in the direction of arrow B smoothly connected to the upper end of the vertical surface 68A. And the vertical surface 68A
Is provided with an arcuate portion 68C that is smoothly connected to the lower end and has a downwardly convex cross-sectional shape along the paper conveyance direction.

Between the fixed guide surface 68 and the guide surface 64, the sheet P conveyed from below is transferred to the registration roll 3.
The transport path 69 guides toward zero.

On the fixed guide surface 68, a small-diameter roller 70 is rotatably provided at a connection portion between the vertical surface portion 68A and the inclined portion 68B.

The roller 70 partially protrudes from the fixed guide surface 68 and rotates when it comes into contact with the paper P being conveyed.

Normally, the upper guide assembly 58
The guide surface 64 and the vertical surface portion 68A are locked by lock nails (not shown) so as to face each other (positions shown in FIGS. 1, 3, and 4).

The upper guide assembly 58
By releasing the lock of the lock claw, as shown in FIG. 5, the lock pawl can be rotated in the direction of the arrow CCW (counterclockwise direction in FIG. 5).
A is largely exposed upward.

Further, on the main body frame side of the image forming apparatus 10, a lower guide assembly 72 is provided diagonally below the second paper feed roll 40 in the direction of arrow B.

As shown in FIG. 5, the lower guide assembly 7
2 is a fixed guide surface 72A opposed to the fixed guide surface 68
And a fixed guide surface 7 having a substantially concave arc shape in cross section along the paper transport direction for guiding the paper P transported from the second paper feed roll 40 toward the registration roll 30.
2B.

The fixed guide surface 72B is provided only in the central portion of the lower guide assembly 72 in the paper width direction orthogonal to the paper transport direction (the direction of the front and back of the paper in FIG. 5). A movable guide member 74 is provided on both sides in the direction.

The movable guide member 74 is rotatably mounted on the shaft 73 of the lower guide assembly 72. The movable guide member 74 has a guide surface 74A formed in the same cross-sectional shape as the fixed guide surface 72A at the center and a fixed portion at the center. It has a guide surface 72B and a guide surface 74B formed in the same cross-sectional shape.

Normally, the movable guide member 74 is arranged such that the guide surface 74 extends on an extension of the fixed guide surface 72B in the paper width direction.
A is fixed by a lock mechanism (not shown) so as to be positioned (see FIGS. 2, 3, and 4).

Then, as shown in FIG. 5, the movable guide member 74 releases the shaft 73 by unlocking the lock mechanism.
In the direction of arrow CW (clockwise in FIG. 5)
This allows a large opening upward between the fixed guide surface 68 and the movable guide member 74.

As shown in FIG. 3, between the fixed guide surface 72B and the second paper supply roll 40 and between the guide surface 74B and the second paper supply roll 40, the second paper supply roll 40 The conveyance path 75 guides the sheet P conveyed in the direction toward the registration roll 30.

As shown in FIGS. 2 and 4, the fixed guide surface 68
A guide surface 76 is provided on the lower side. Between the fixed guide surface 68 and the guide surface 76, the transport path 7 of the sheet P
The end of the conveyance path 78 on the side of the arrow B is connected to an opening 80 on the side of the apparatus.

A pair of rollers 82 for transporting the sheet P are provided in the middle of the transport path 78. The roller 82 is
The sheet P is rotated by a motor (not shown) so that the sheet P can be transported in the directions indicated by arrows B and F.

A paper reversing device (not shown) for reversing the paper P can be connected to the rear side (the direction of the arrow B) of the image forming apparatus 10.
8 is a conveyance path 75 due to the reverse rotation of the registration roll 30.
Is guided to the sheet reversing device, and
It has a function of guiding the sheet P that has been inverted and discharged by the sheet inverting device toward the transport path 75. (Paper Detecting Mechanism) As shown in FIG. 1, the upper guide assembly 58 includes a first actuator 84 used to detect the paper P that has entered the transport path 65, and a sheet P that has entered the transport path 69. A second actuator 86 used for detection is provided.

The first actuator 84 is integrally provided with a shaft 84A, which is rotatably inserted into a hole (not shown) of the upper guide assembly 58. For this reason, the first actuator 84 can swing about the shaft 84A as the center of rotation.

The second actuator 86 has a hole 86B as shown in FIG.
The shaft 84A of the first actuator 84 is inserted into B. For this reason, the second actuator 86 and the first actuator 84 are relatively rotatable within a certain range.

As shown in FIG. 1, the first actuator 84 has a torsion spring 85 shown in FIG. 7 (one end is locked to the upper guide assembly 58 and the other end is locked to the first actuator 84, so that the torsional force is Is strong in the clockwise direction in FIG. 1, and usually, the protrusion 8 on the side surface 84C side is used.
4D abuts the upper guide assembly 58 and is at the position shown in FIG.

On the other hand, the second actuator 86
The torsion spring 87 shown in FIG.
The other end is locked to the second actuator 86,
The torsional force is weaker than the torsion spring of the first actuator 84. ) Is urged in the counterclockwise direction in FIG.

Note that the second actuator 86 is integrally formed with a projection 86A, and this projection 86A normally comes into contact with a projection 84B formed integrally with the first actuator 84. Thus, it is at the position shown in FIG.

On the fixed guide surface 68 on the body frame side,
A transmission type optical sensor 88 is provided. The optical sensor 88 includes a control device 89 for controlling the entire device.
(See FIG. 2).

Normally, the tip of the second actuator 86 traverses the transport path 69 and blocks the light beam of the optical sensor 88.

When the sheet P comes into contact with the second actuator 86, and the second actuator 86 rotates clockwise in FIG. 1 and the light beam of the optical sensor 88 is transmitted, the sheet P enters the transport path 69. Can be detected.

Further, the paper P is transferred to the first actuator 84.
When the first actuator 84 rotates counterclockwise in FIG. 1, the second actuator 86 rotates in the counterclockwise direction in FIG. Is transmitted, it is possible to detect that the paper P has entered the transport path 65. (Operation) Next, the operation of the image forming apparatus 10 of the present embodiment will be described.

First, the conveyance of the sheets P stacked on the first sheet tray 34 will be described.

As shown in FIG. 6, the first paper feed roll 38
Is rotated in the arrow CW direction, the uppermost sheet P in contact with the outer peripheral surface of the first sheet supply roll 38 is transported toward the transport path 65.

The first separating member 42 (similarly for the second separating member 44) is made of a material having a large friction with the sheet P as in the prior art. Since the traveling of the lower sheet P is suppressed by a friction force larger than the friction force, only the upper sheet P is conveyed.

Further, when the first sheet supply roll 38 rotates in the direction of arrow CW and the sheet P enters the conveyance path 65, the leading end is guided to the upper guide surface 62 (the upper flat portion 62A and / or the arc portion 62B). As a result, the transport direction of the paper P is changed obliquely downward, and when the paper P is further transported, the leading end of the paper P is guided by the lower guide surface 60 (second arc portion 60C), and the transport direction is diagonally upward. It is changed and transported between the rolls 30A and 30B.

The first sheet supply roll 38 stops after one rotation. When the sheet P enters the transport path 65, the first actuator 84 and the second actuator 86
Is rotated and the light beam of the optical sensor 88 is transmitted, so that it is detected that the paper P has entered the transport path 65,
After a lapse of a predetermined time (preset by the control device 89), the registration roll 30 rotates.

Here, the state when the sheet P enters the transport path 65 will be described in detail. First, as shown in FIG.
The leading end of the sheet P contacts the side surface 84C of the actuator 84 at approximately 90 °.

When the sheet P is further conveyed, as shown in FIG. 9, the first actuator 84 further rotates, but the leading end of the sheet P is approximately 90 degrees with respect to the side surface 84 C of the first actuator 84. Abut at °. Note that the first actuator 84 and the second actuator 86
Since the projection 84B and the projection 86A abut against each other by the action of the torsion spring 87, the first actuator 84 and the second actuator 86 rotate around.

When the sheet P is further conveyed, the first actuator 84 further rotates as shown in FIG. 10, but the angle of the leading end of the sheet P with respect to the side surface 84C of the first actuator 84 becomes smaller. The angle change is smaller than the angle change of the first actuator 84.

When the sheet P is further conveyed, the first actuator 84 further rotates as shown in FIG.
Paper P against side surface 84C of first actuator 84
Although the angle of the leading end of the registration roll 30 is very small, the leading end of the sheet P is hardly curved in the sheet width direction,
Can be rushed into.

Therefore, when the registration roll 30 is
Does not cause wrinkles on the paper P.

The paper P sandwiched between the registration rolls 30 is further conveyed upward, and after a lapse of a predetermined time (preset by the control device 89), writing of an image is started. Then, the toner image on the image carrier 12 is transferred onto the sheet P, and the fixing device 24 fixes the toner image.

Next, conveyance of the paper P stacked on the second paper tray 36 will be described.

[0115] As shown in FIG.
Is rotated in the arrow CW direction, the uppermost sheet P in contact with the outer peripheral surface of the second sheet supply roll 40 is transported toward the transport path 75.

Further, when the second paper supply roll 40 rotates in the direction of arrow CW and the paper P is conveyed, the leading end of the paper P
The fixed guide surface 72B and the guide surface 74B, the fixed guide surface 68, and the guide surface 64 are contacted and guided in this order, and are finally directed between the rolls 30A and 30B.

The second paper feed roll 40 stops after one rotation. When the paper P enters the transport path 69, the second actuator 86 rotates as shown in FIG. 12, and the light beam of the optical sensor 88 is transmitted, so that the paper P enters the transport path 69. After the detection and the elapse of a predetermined time, the registration roll 30 rotates.

The paper P sandwiched between the registration rolls 30 is further conveyed upward, the toner image on the image carrier 12 is transferred, and the fixing device 24 fixes the toner image.

Here, in the event that a conveyance failure such as the paper P jamming in front of the registration roll 30 occurs for some reason, the top plate 10A is opened and the developing unit 2 is opened from the inside.
Remove 7

Since a space is left above the registration roll 30 after the development unit 27 is removed therefrom, the upper guide assembly 58 can be easily operated therefrom.

By rotating the upper guide assembly 58 in the direction of the arrow CCW as shown in FIG. 5 (counterclockwise direction in FIG. 5), the paper P near the registration roll 30 such as the transport path 65 and the transport path 69 can be removed. The paper P can be easily viewed from above and can be easily removed. Since the toner sensor 90 is attached to the upper guide assembly 58 and retracts together with the upper guide assembly 58, the toner sensor 90 does not hinder the removal of the paper P.

Further, since the optical sensor 88 is provided on the fixed guide surface 68 on the main body frame side and is separated from the first actuator 84 and the second actuator 86, it is possible to prevent the occurrence of troubles in the electric system such as disconnection of the wiring. be able to.

By rotating the movable guide member 74 in the arrow CW direction (clockwise direction in FIG. 5) as shown in FIG. 5, the paper P on the transport path 75 and the transport path 78 near the movable guide member 74 is moved. Can be viewed from above, and the paper P can be easily removed.

[0124]

As described above, since the image forming apparatus according to the first aspect has the above-described configuration, the number of components of the paper detecting mechanism can be reduced, and the size of the paper detecting mechanism can be reduced. It has an excellent effect.

Since the image forming apparatus according to the second aspect is configured as described above, the size of the paper detecting mechanism is smaller than that of rotating the first actuator and the second actuator about separate rotation axes. It has an excellent effect that it can be made.

Since the image forming apparatus according to the third aspect has the above-described configuration, even when the guide member is moved, the sensor does not need to be moved, thereby preventing the occurrence of a trouble in the electric system. Has an excellent effect that

Since the image forming apparatus according to the fourth aspect has the above-described configuration, it has an excellent effect that it is possible to prevent the vicinity of the leading end of the sheet from being bent by the recoil coming into contact with the first actuator.

Since the image forming apparatus according to the fifth aspect has the above-described configuration, it has an excellent effect that the generation of the curvature near the leading end of the conveyed sheet can be further suppressed.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view illustrating a main part of a sheet feeding device of an image forming apparatus according to an embodiment of the present disclosure.

FIG. 2 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention.

FIG. 3 is a side view illustrating the vicinity of an upper guide assembly of the sheet feeding device of the image forming apparatus according to the embodiment of the present disclosure.

FIG. 4 is a schematic configuration diagram illustrating a sheet feeding device in a normal state.

FIG. 5 is a schematic configuration diagram illustrating the sheet feeding device in a maintenance state such as a sheet jam.

FIG. 6 is an exploded perspective view of a first actuator and a second actuator.

FIG. 7 is a perspective view showing a state in which a first actuator, a second actuator, and two torsion springs are combined.

FIG. 8 is an enlarged cross-sectional view illustrating a main part of the sheet feeding device.

FIG. 9 is an enlarged cross-sectional view illustrating a main part of the sheet feeding device.

FIG. 10 is an enlarged sectional view showing a main part of the sheet feeding device.

FIG. 11 is an enlarged sectional view showing a main part of the sheet feeding device.

FIG. 12 is an enlarged cross-sectional view illustrating a main part of the sheet feeding device.

[Explanation of symbols]

 Reference Signs List 10 image forming apparatus 16 image writing apparatus (image forming section) 27 developing unit (image forming section) 30 registration roll 34 paper tray (first paper tray) 36 paper tray (second paper tray) 58 upper guide assembly (guide) (Member) 65 Transport path (first transport path) 69 Transport path (second transport path) 84 First actuator 84B Projection (synchronization means) 84C Side surface (sheet contact surface) 85 Torsional spring (synchronization means) 86 2 actuator 86A Projection (synchronization means) 87 Torsional spring (synchronization means) 88 Optical sensor (sensor)

Continued on the front page F term (reference) 3F048 AA01 AB01 BA05 CC17 DC02 EB02 EB33 3F101 FB01 LA01 LB03 3F102 AA01 AB01 BA02 BB02 CA01 CA03 CB01 DA08 EA01 FA08 3F343 FA02 FB01 GA03 GB01 GC01 GD01 HB02 HB08 HD18 KB01 LA04 MA54 MC08

Claims (5)

[Claims] An image forming unit that forms an image on a sheet; a registration roll that conveys the sheet to the image forming unit; and a first guide that guides the sheet sent from a first sheet tray toward the registration roll. And a second transport path that guides the paper sent from the second paper tray toward the registration roll, and a second transport path that contacts the paper transported in the first transport path. A first actuator that is rotationally displaced from a first position to a second position, and a first actuator that is rotationally displaced from the first position to a second position when the sheet conveyed in the second conveyance path abuts on the first actuator. A second actuator; a sensor for detecting that the first actuator has been rotationally displaced to a second position; and a sensor for detecting that the second actuator has been rotationally displaced to a second position. Image forming apparatus characterized by having a means sync, which in synchronism with the Chueta rotationally displacing the first actuator to the second position. 2. The image forming apparatus according to claim 1, wherein the first actuator and the second actuator rotate around one rotation axis. 3. A device provided between the first transport path and the second transport path to form at least a part of the first transport path and to form at least a part of the second transport path. A guide member, wherein the first actuator, the second actuator, and the synchronization unit are provided on the guide member, and the sensor is provided on a member different from the guide member. The image forming apparatus according to claim 1 or 2. 4. The first actuator and the second actuator
When at least one of the actuators is at the first position, the sheet contact surface on the upstream side in the sheet conveyance direction is the sheet contact surface when viewed from the sheet width direction orthogonal to the sheet conveyance direction. 4. The image forming apparatus according to claim 1, wherein the image forming apparatus is set at substantially 90 ° with respect to the sheet conveying direction upstream of the sheet conveying direction. 5. The paper transport direction upstream of the paper abutment surface when viewed from a paper width direction orthogonal to the paper transport direction when the paper abutment surface is at the first position. The image forming apparatus according to claim 4, wherein an angle with respect to the angle gradually decreases as the distance from the rotation axis increases.