JP3178599B2 - Image forming device - Google Patents

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 main body having a recording paper supply path on one side, and a recording paper conveyance path formed to a discharge port on the other side after performing transfer and fixing. ,
The present invention relates to an image forming apparatus provided below the apparatus main body and independent of the apparatus main body, and having a recording paper transport unit capable of receiving the transfer paper discharged from the discharge port.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No.
As described in Japanese Patent Laid-Open No. 1 (Kokai) No. 1 (1999) -1990, there is known an image forming apparatus in which an image forming apparatus main body is mounted on an L-shaped reversing unit. However, the conventional technique requires twice as long time as printing once to complete printing of one sheet of recording paper in order to print the recording paper again.

[0003]

On the other hand, there has recently been a demand for shortening the time required to transfer an image onto a recording sheet and fix it. However, the recording paper conveyance speed in the apparatus main body cannot be increased unnecessarily depending on the image forming speed in the photosensitive drum. And
In the form of the L-shaped unit, if the printing time can be shortened, the re-feeding of the recording paper is not limited to the case of printing on both sides of the recording paper,
By feeding the recording paper to the apparatus body without turning over the upper and lower surfaces, the present invention can be applied to a mechanism for printing a picture different from the first picture on the same face.

[0004] In view of the above-mentioned circumstances, an object of the present invention is to provide a recording paper transport unit that reduces the image processing time. Another object of the present invention is to provide a recording apparatus having a configuration in which an L-shaped unit is mounted on an apparatus main body and a reasonable paper passage is provided in the L-shaped unit so that recording paper can be conveyed at high speed. The object is to provide a paper transport unit. Another object of the present invention is to provide a recording paper transport unit that stops the transport of the recording paper and stands by when there is a preceding recording paper downstream even when the recording paper is transported at a high speed. It is.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an image forming apparatus having a recording paper supply path on one side, and a recording paper conveyance path formed to a discharge port on the other side after performing transfer and fixing. An image forming apparatus including a main body (hereinafter, referred to as an apparatus main body) and a recording sheet transport unit provided below the apparatus main body and independently of the apparatus main body and capable of receiving transfer paper discharged from the discharge port. Wherein the recording paper transport unit is provided with a base portion on which the apparatus main body is placed, and a paper passing portion which rises from the base portion and has a transport path connecting the discharge port and the base portion, and has an L-shaped cross section. And a paper-passing-portion conveying motor for providing one or a plurality of conveying rollers on the conveying path of the paper-passing unit, and controlling the conveying rollers in two stages in a low-speed conveying state and a high-speed conveying state. Is provided independently of the base, and the rear end of the recording paper is After passing through the fixing operation zone Okimoto body switches the conveying motor the sheet passing portion in high-speed conveyance state,
After the rear end of the transfer sheet has passed through the sheet passing unit, the sheet passing unit transport motor is switched to a low-speed transport state.

Here, the one surface side and the other surface side may be a front surface side and a rear surface side, or one of both side surfaces may be the one surface side or the other surface side. The unit having an L-shaped cross section is a unit that receives recording paper from the discharge port on the apparatus main body side by the paper passing unit and supplies the recording paper to the recording paper supply path on the apparatus main body side by the base unit. The printing reversing unit or the single-sided multi-printing unit may be used.

The recording paper transport unit includes a base on which the apparatus main body is placed, and a discharge unit on the other side, which stands on the base and is disposed downstream after transferring and fixing the apparatus main body. An outlet and a paper passing section having a transport path connecting the base are provided, and are formed in an L-shaped cross section.

[0008] Further, the paper passing section is provided with one or more transport rollers on a transport path of the paper passing section, and the transport rollers are controlled in two stages in a low speed transport state and a high speed transport state. A motor is provided independently of the base, and after the trailing edge of the recording paper has passed through the fixing operation area of the apparatus main body, the paper passing section transport motor is switched to a high-speed transport state, and the trailing edge of the transfer paper is fed through the After passing through the paper section, the paper passing section transport motor is switched to a low-speed transport state.

As described above, since the paper passing unit transport motor separate from the base transport motor is disposed in the paper passing unit,
Each can control the speed independently. That is,
During the fixing of the recording paper in the apparatus main body, the conveying roller is rotated at a low speed state substantially equal to the recording paper conveying speed on the apparatus main body side to receive the recording paper in the paper passing portion of the unit. The recording paper is introduced into the introduction passage at a high speed by switching to a high speed state faster than the state and rotating the transport roller. Therefore, the time required for completing the transfer to the recording paper can be reduced.

The paper passing unit is configured to be rotatable in a direction away from the rear surface of the apparatus main body on which the paper is placed, and the transport roller and the paper transport unit transport motor are rotated in accordance with the rotation operation. Is also an effective means of the present invention.

According to this technical means, the transport roller and the paper-passing-portion-portion motor are arranged close to each other in the paper-passing portion, so that the driving force transmission mechanism between the transport motor and the transport roller is simplified. Even if the paper passing unit is separated from the rear surface of the apparatus main body side, the transport motor and the transport roller rotate integrally, so that the transmission mechanism is not connected to the base, so that the paper is not cut. Even if the paper passing unit is returned to the rear side of the apparatus main body, a problem such as reconnection of the transmission mechanism does not occur.

[0012]

Embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely described. It is only an example.

FIG. 1 is a schematic configuration diagram of an image forming apparatus using a recording paper transport unit according to an embodiment of the present invention.
FIG. 3 is an enlarged view of a main part of FIG. 1, and FIG. 3 is an explanatory diagram illustrating a state in which the image forming apparatus main body, the reversing unit, and the sheet feeding unit are stacked and arranged. In FIG. 3, the positioning pins 5 on the reversing section 26 of the paper reversing unit (recording paper transport unit) 2
4 and 54 are fitted in device holes 52 and 52 formed in the lower surface of the image forming apparatus main body (hereinafter referred to as the apparatus main body) 1, and a terminal 5 is provided.
7, the electrical connection between the apparatus main body 1 and the sheet reversing unit 2 is completed.

When a paper cassette (built-in cassette) 6 longer than the length of the apparatus main body 1 in the front-rear direction is set in the apparatus main body 1, as shown in FIG. Since the end protrudes from the rear surface 1b of the apparatus main body 1, the paper passing portion 5 needs to be inclined outward. To incline the sheet, the sheet passing section 5 may be rotated counterclockwise with respect to the apparatus main body 1 by the arm 30 as shown in FIG. As shown in FIG. 4, a back cover (not shown) is detachably provided on the back surface 1b of the apparatus main body 1. The rear cover is detached from the apparatus main body 1 when it is combined with the sheet reversing unit 2.

Similarly, the device holes 53, 53 of the sheet reversing unit 2 and the positioning pins 55, 5
5 and the terminal 58 completes the electrical connection between the sheet reversing unit and the sheet feeding unit 3. It should be noted that a plurality of paper feed units having the same size can be mounted in a multi-stage manner, so that a large-capacity image can be recorded.

Further, as shown in FIG.
An electric controller 4 is built in and the terminal 5
The sheet reversing unit 2 and the sheet feeding unit 3 are connected to the controller 4 via 7, 58. A paper cassette (built-in cassette) 6 is provided above the controller 4.
Are arranged, and a multi-purpose tray 8 is provided on the front side of the apparatus main body so that various types of paper can be supplied.

Therefore, an image can be formed on the recording paper even if the paper feed unit 3 is not provided. However, a frequently used recording paper such as A4 size is used for the paper It is preferable that the cassette 6 uses recording paper larger than the recording paper accommodated in the paper feeding unit 3 (for example, A3 size), and that the multi-purpose tray 8 use recording paper smaller than the recording paper used for the paper feeding unit 3. .

A transport unit 10 configured to detachably mount the paper feed cassette 6 is detachably disposed on the apparatus main body 1 (FIG. 5), and a well-known electronic unit is mounted on the apparatus main body 1 and the transport unit 10. Photographic processing means is arranged. A photosensitive drum 9 and a paper feed roller 15 are arranged on the apparatus body 1 side, and are configured to be able to convey the recording paper from the multi-purpose tray 8 to the photosensitive drum 9 side. On the front surface 1a side of the apparatus main body 1 adjacent to the controller 4, a paper path unit 47 for obtaining a driving force from a motor 45 provided in a reversing unit 26 of the sheet reversing unit 2 described later, and a transport roller 48 are provided. Reversing unit 2
The recording paper from the printer can be conveyed to the apparatus main body 1 side. Note that a charger, a cleaning device, a developing device, a latent image forming device, and the like necessary around the photosensitive drum 9 are not shown for convenience.

On the downstream side of the photosensitive drum 9, a pair of fixing rollers 18, a pair of conveying rollers 19, and a guide 2 for switching the paper discharge direction are provided.
4 (FIG. 2), and the guide 24
Side or the paper passing unit 5 side. The switching of the guide 24 is performed by the operation of the front front panel 25 of the apparatus main body 1 or the paper reversing unit 2.
In the double-sided recording mode, the selection can be automatically switched.

In the single-sided recording mode, the guide 24 forms a path to the paper discharge unit 22 side, and the recording paper
0, the sheet is conveyed to a sheet discharge section 22 via a sheet discharge roller pair 21. In the double-sided recording mode, the guide 24 forms a path to the paper passing unit 5 of the sheet reversing unit 2 described later, and when the image formation on one side of the recording paper is completed, the recording paper is conveyed to the paper passing unit 5. When the recording paper starts image formation on the other side, the guide 24 is switched to form a passage to the paper discharge unit 22 side.

On the transport unit 10 side, a photosensitive drum 9 is provided.
A registration roller pair 17, a registration sensor 11, a transport roller 16, and a pickup roller 7 are disposed on the upstream side of the transfer roller 12. 1 on the front 1a side,
A multi-purpose tray 8 is arranged so as to be openable and closable (FIG. 2).

Therefore, the transport unit 10 includes the multi-purpose tray 8, the transport rollers 16, and the pair of registration rollers 1.
7. The transfer roller 12 can be integrally pulled out of the apparatus main body 1, and the recording paper jam having a leading end between the photosensitive drum 9 and the fixing roller pair 18 and the recording in the transport path on the front side of the jam. It is possible to deal with paper jams.

Next, the configuration of the sheet reversing unit 2 will be described. The paper reversing unit 2 has an L-shaped overall cross-sectional shape, and includes a reversing unit 26 for reversing and feeding recording paper, and a paper passing unit 5.
It is composed of The reversing part 26 is formed by a long side having a front-rear length longer than the front-rear length of the apparatus main body 1 and a short side having the same length as the lateral width of the apparatus main body 1. ing.

The paper passing portion 5 is formed upright on a portion of the upper surface of the reversing portion 26 where the apparatus main body 1 is not placed.
The left chamber 5a and the right chamber 5b (FIG. 3) are connected to each other by a support (not shown) and integrally formed. The arm 30 to which the left chamber 5a and the right chamber 5b are fixed is rotated with respect to the apparatus main body 1. It is configured so that it can be moved and separated.

As shown in FIG. 2, the paper passing section 5 includes a pair of conveying rollers 29 for receiving the recording sheet from the apparatus main body 1 and conveying the recording sheet to a downstream side, and a discharge tray disposed downstream of the pair of conveying rollers 29. A discharge roller pair 28 that discharges the recording paper to 31, a conveyance roller pair 34 that is disposed downstream of the conveyance roller pair 29 and conveys the recording paper to the reversing unit 26 side, and is disposed at a discharge port to the reversing unit 26. A sensor (paper passing section sensor) 36, a switching guide 32 disposed between the transport roller pair 29 and the paper discharge roller pair 28 for switching the transport of the recording paper between the paper discharge tray 31 and the reversing section 26, 32, a space in which the rear end of the paper feed cassette 6 is inserted, a motor (paper feed section conveying motor) 35 disposed on the left chamber 5a side of the space, and the like.

The recording paper in the paper passing section 5 is driven by a driving force transmitted from a motor 35 via a belt 61.
The belt 61 includes a rotating shaft 35 a of the motor 35 and the roller 5.
0, one roller 29A of the pair of transport rollers, one roller 28A of the pair of discharge rollers 28, and one roller 34A of the pair of transport rollers 34. And
The roller 50 is disposed so as to be slightly adjustable left and right in order to adjust the tension of the belt.

The space into which the leading end of the sheet cassette 6 is inserted is provided at a substantially central portion of the sheet passing section 5 avoiding the rollers, and the motor 35 is also provided in the area where the sheet cassette 6 extends. It is arranged at a position shifted laterally. A flat motor is used as the motor 35, and the lengths of the conveying roller pairs 29 and 34 and the belt 61 are set to be substantially the same from the motor rotation shaft 35a. It is desirable to set. Note that the motor 35 and each roller may be connected by a gear. Further, the connecting portion between the discharge roller 28A and the belt 61 is separate from the connecting portion between the discharging roller 28A and the belt 61, and the connecting portion between the discharging roller 28A and the belt 61 is frictionally connected.
It is desirable that the difference in feed speed between the above and the above can be adjusted by the friction.

As described above, the controller 4 is disposed at the lowermost portion of the apparatus main body 1, the paper feed cassette 6 of the transport unit 10 is located thereon, and the fixing roller is located on the upper surface side of the transport unit 10 from the recording paper transport start end. Since the transport path to the pair 18 is formed, the vertical distance from the transport path to the lower surface of the apparatus main body 1, that is, the height can be increased. This means that the reversing portion 26 facing the bottom surface of the apparatus main body 1 from the receiving port on the paper passing section 5 side for receiving the recording paper transferred from the recording paper discharge port on the apparatus main body side communicating with the conveyance path. Therefore, the distance to the upper surface of the motor 5 can be increased, so that the paper transport path in the paper passing unit 5 can be formed in a large arc shape around the rotation axis of the motor 5, and unreasonable bending can be prevented. A sufficient transport space can be secured.

The reversing section 26 is provided along the transport path with the transport rollers 3.
7A and 37B, a sensor (introduction path sensor) 38, a pair of transport rollers 39A and 39B to which a driving force is transmitted from a motor (introduction motor) 49, a sensor (inter-path sensor) 40, and a driving force from a step motor (discharge motor) 44. Rollers 41A and 41B, to which power is transmitted, and sensors (reversing path sensors)
42, a tension roller 43 for adjusting the tension of the belt 62 stretched around the drive roller portion 39A of the transport roller pair 39 and the drive roller portion 37A of the transport roller pair 37;
Transport roller pairs 46A and 46B to which a driving force is transmitted from a motor (transport motor) 45 are provided. The motor 45 is configured to be able to transmit a driving force to the transport roller 48 of the paper path unit 47 via a gear train (not shown).

The recording paper transported by the transport roller pairs 37, 39 and 41 passes through the sensor 42 at the leading end and is transported further to the back than the transport roller pair 43. It stops in the state of being pinched by the pair 41. At this time, the rotation of the motor 49 that drives the transport roller pairs 37 and 39 and the tension roller 43 also stops.

When the recording paper is fed reversely, the recording paper is rotated by the reverse rotation of the forward / reverse motor 44 while the pair of conveying rollers 41 sandwich the recording paper.
The reverse feed of 1 is reversed. Then, the sheet is conveyed to the apparatus main body 1 by the motor 45 via the conveying roller pair 46. Here, the sensors 38, 40, and 42 detect the leading and trailing ends of the recording paper and control the forward and reverse rotation of the motor 44. That is, while the recording paper is being detected by the sensor 38, the motor 44 continues to rotate forward, and continues to rotate forward when the sensor 40 is on and the sensor 42 is on, but when the sensor 40 is off. Stop rotation.

Next, the operation of performing double-sided printing using the sheet reversing unit 2 will be described in more detail. In this embodiment, the motor and the sensor are arranged and controlled at predetermined positions in the unit so as to reduce the waiting time when performing double-sided printing, and the speed of the transport motor 35 is controlled by the paper transport position. The switching between the forward and reverse rotations of the transport motor 49 and the forward and reverse rotation of the reverse motor 44 are performed.

The condition that the registration roller pair 17 in the apparatus main body 1 conveys the recording paper to the transfer roller 12 side is determined by the sensor 1
Third, the sensor 36 and the sensor 38 do not detect the recording paper. Then, the operation of the transport motor 35 arranged in the paper passing section 5 is started in response to the operation of the registration sensor 11 arranged in front of the registration roller pair 17 of the apparatus main body 1. Then, gradually increase the rotation speed.
Slow-up control for shifting to low-speed rotation (linear speed of 163 mm / sec) is performed over 5 seconds. As a result, it is possible to prevent the skew in the sheet reversing unit 2, that is, the non-uniformity of the sheet feeding function due to the twisting or bending at the time of starting the conveying member.

Therefore, when the apparatus main body 1 starts printing, the paper reversing unit 2 enters an operable standby state. When the trailing edge of the recording paper on which the image has been transferred to one side is detected by the sensor 13 disposed downstream of the pair of fixing rollers 18, the transport motor 35 rotates at a timing at which the trailing edge comes off the pair of transport rollers 19. (Linear speed 282 mm / sec)
When it is detected that the trailing edge of the recording paper has reached the sensor 36, the rotation is switched to the low-speed rotation in a standby state, and the recording paper corresponding to the next recording paper is sent.

When the sensor 13 detects the trailing edge of the next recording sheet, the rotation is switched from low-speed rotation to high-speed rotation. As described above, the transport motor 35 is switched from the low speed to the high speed in synchronization with the end of fixing of the recording paper, and is controlled so as to immediately transport the recording paper to the reversing unit 26.

On the other hand, after the sensor 42 in the reversing unit 26 detects the transferred recording paper in the conveyance path 70, the sensor 42 in the conveyance path 70 waits until the leading end of the recording paper is detected by the sensor 11. The end is configured to escape the detection area of the sensor 42.

The rotation speed of the motor 49 reaches a high speed by the time the sensor 36 detects the leading end of the recording paper in the paper passing unit 5. When the transfer paper reaches the transport roller pair 37, the rotation speed is high. Done.

Therefore, the leading end of the recording paper that has passed the sensor 36 enters the conveyance path 69 at a high speed, and the conveyance roller pair 3
When the sensor 38 detects between 7 and 39 and the leading edge of the recording paper is detected by the sensor 38, the motor 44 starts high-speed forward rotation. Further, after the leading edge of the recording paper is detected by the sensor 40, the sensor is detected by the sensor 42, and the trailing edge is detected by the sensor 4.
The motor 49 and the motor 4
4 stops. At that time, the transport rollers 41A and 41A
B stops with the recording paper sandwiched.

The motor 49 and the motor 49 are provided on condition that the recording paper is conveyed by the registration roller 17 and the recording paper is not conveyed from the conveyance path 71, and that the sensor 36 does not detect the leading end of the recording paper. Motor 4
4 is reversed and re-fed to the apparatus main body 1. At this time, the number of steps of the motor 44 is counted at the same time as the reverse rotation of the motor 44, and the motor 49 is rotated in the reverse direction until the rear end of the re-recorded recording paper is out of the drive range of the transport rollers 41A and 41B. Stop. The motor 49 may be stopped at a timing when the trailing edge of the recording paper is out of the driving range of the tension roller 43. In this state, the motor 49 can rotate forward to enter a state of receiving the recording paper from the paper passing unit 5. Therefore, it is desirable that the tension roller 43 is located at the left end of the transport path 70 as much as possible.

Further, even if the motor 49 is conveying the recording paper and the trailing end of the recording paper loses the detection of the sensor 36, the conveyance path 7
When the recording paper at 0 does not fall out of the holding area of the transport roller pair 41, the motor 49 stops and the recording paper is made to wait in the transport path 69. When the sensor 42 detects the trailing edge of the recording sheet and rotates until the recording sheet moves out of the holding area of the pair of conveying rollers 41, the motors 49 and 44 rotate forward and a new path The recording paper will be conveyed.

Further, the discharge roller 46 connected to the carry-out motor 45 is configured to perform registration at the time of re-feeding the sheet into the apparatus main body 1 using the nip of the roller.

[0042]

As described above, according to the present invention, separately from the base transport motor provided at the base of the L-shaped unit,
Since the paper feed unit transport motors are arranged in the paper feed unit and the speed can be independently controlled, it is possible to switch the paper feed unit transport motor to a high-speed state and introduce the recording paper into the introduction passage at high speed. Thus, the time required for completing the transfer to the recording paper can be shortened.

Further, the rotation speed of the introduction motor for guiding the recording paper to the outlet side of the apparatus main body which communicates with the recording paper supply path is controlled so as to substantially match the conveying speed of the recording paper from the paper passing portion. Paper can be received and smoothly transported to the exit side. It has a remarkable effect.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus using a recording paper transport unit according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an explanatory diagram illustrating a state in which an image forming apparatus main body, a sheet reversing unit, and a sheet feeding unit are stacked and arranged.

FIG. 4 is a perspective view showing a rear end portion of the apparatus main body.

FIG. 5 is a perspective view showing a transport unit.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Image forming apparatus main body 2 Paper reversing unit (recording paper transport unit) 5 Paper passing unit 26 Reversing unit (base) 29, 34 Transport roller 35 Paper passing unit transport motor 69 Transport path (base transport path) 71 Transport path (recording paper) Supply path)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Murakami 3-9 Tamazuki Motomachi, Tennoji-ku, Osaka-shi, Osaka Mita Techno Design Co., Ltd. Examiner Makoto Nagayasu (58) Field surveyed (Int. Cl. ⁷ , DB Name) B65H 85/00 B65H 5/06 B65H 29/58

Claims (2)

(57) [Claims] 1. An image forming apparatus main body (hereinafter, referred to as an apparatus main body) having a recording paper supply path on one surface side, and having a recording paper conveyance path formed toward a discharge port on the other side after performing transfer and fixing. , Provided below the device body independently of the device body,
An image forming apparatus having a recording paper transport unit capable of receiving the transfer paper discharged from the discharge port, wherein the recording paper transport unit stands up from the base and a base on which the apparatus main body is placed. A paper passing portion having a transport path connecting the discharge port and the base is provided to form an L-shaped cross section, and the paper passing portion includes one or a plurality of transport rollers on the transport path of the paper passing portion. And a paper-passing-portion conveyance motor for controlling the conveyance rollers in two stages, a low-speed conveyance state and a high-speed conveyance state, independently of the base, and after the rear end of the recording paper has passed the fixing operation area of the apparatus main body. Switching the paper passing unit transport motor to a high-speed transport state,
An image forming apparatus, wherein after the rear end of the transfer paper has passed through the paper passing unit, the paper passing unit transport motor is switched to a low-speed transport state. 2. The paper feed unit is configured to be rotatable in a direction away from a rear surface of the apparatus main body side on which the paper feed unit is placed, and the transport roller and the paper transport unit transport motor are synchronized with the rotation operation. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus also rotates integrally.