JPH04251065A - Paper conveying device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention can be applied to recording apparatuses that record on paper by printing, transferring, copying, printing, etc., such as printers, copying machines, facsimile machines, and printing machines. Specifically, in such a recording device, the transport roller
The present invention relates to a paper transport device that transports paper from one direction by a branch path and sends it to two directions.

0002

2. Description of the Related Art Conventionally, this type of paper conveying device has been provided with a switching pawl B in a branch path A and a first pair of conveyance rollers C arranged at the entrance of the branch path A, for example, as shown in FIG. At the same time,
A second pair of conveyance rollers D and a third pair of conveyance rollers E are arranged at the exit. After the image transferred to the paper F is fixed by the fixing unit G, the paper F is discharged by the first pair of conveying rollers C and sent to the branch path A, and is sorted in two directions by the switching claw B. Second conveyance roller pair D or third conveyance roller pair E
I was sending him out.

By the way, in the above-mentioned paper conveying device, as shown in FIG.
is fixed, the cam K is pulled by the movable rod L of the solenoid S, and returned by the spring M to rotate and drive the switching pawl B.
is switching. Therefore, the switching operation of the switching pawl B requires at least 0.6 seconds, and even taking a margin of 0.8 seconds. Therefore, the paper length is 2
16mm, print speed 30PPM (page/m
Inute), the paper feeding speed (photoreceptor linear velocity) V1mm/s is calculated as follows: V1=30(216+
From 0.8V1)/60, V1=180mm/s.

0004

[Problem to be solved by the invention] However, today,
There is a strong demand for faster printing. Therefore, if the paper feeding speed is simply increased in a conventional paper conveying device of this type, the switching claw B must be switched while the previous paper F1 is passing through the position of the switching claw B, as shown in FIG. 7, for example. As a result, there is a problem in that the rear end of the sheet F1 that is passing through the sheet F1 is caught. Therefore, if the switching claw B is switched after the previous paper F1 has passed, the next paper F1 will be moved as shown in FIG.
There is a problem where 2 is caught in the middle.

On the other hand, the print speed is set to 60 PPM (page/minute), for example, with sufficient paper spacing.
), the paper length is 216 mm, and it takes 0.8 seconds to switch the switching claw B, then the paper feed speed (photoreceptor linear velocity) V2 mm/s is V2 = 60 (216 mm).
+0.8V2)/60, it becomes 1080mm/s,
This is 6 times as much as in the case of 30 PPM. Therefore, this linear velocity of the photoreceptor is too fast and causes many problems in terms of noise, vibration, motor torque, etc., and is not practical. Therefore,
An object of the present invention is to increase the printing speed without significantly increasing the paper feeding speed, and to meet the demand for faster printing.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the invention as set forth in claim 1 provides a method for conveying the material by means of conveying rollers 46, 47, and 48, as shown in the illustrated embodiment below, for example. In a paper conveyance device that distributes paper 45 from different directions through a branch path 28 and sends it out in two directions, a switching roller 50 that distributes the paper 45 in the sending direction to the branch path 28 is provided.
It is characterized by being provided so that it can be rotated in the forward and reverse directions.

[0007] Furthermore, the invention according to claim 2 is based on claim 1.
In the invention described in , on the outer periphery of the switching roller 50,
It is characterized by thin and soft plate-shaped blades 50a provided radially.

Furthermore, in the invention according to claim 1, when the feeding direction of the paper 45 is switched, the paper 45a before the paper 45 whose feeding direction is to be switched is It is characterized in that the switching roller 50 is controlled to rotate in a reverse direction while passing through the position of the roller 50.

[0009]

[Operation] In the invention as claimed in claim 1, the conveyor roller
The paper 45 is conveyed by a roller 46, and the paper from one direction is sent to a branch path 28. The rotation direction of a switching roller 50 is switched between forward and reverse directions to sort the paper 45, and the paper 45 is sent out in two directions by conveyance rollers 47 and 48.

[0010] Furthermore, in the invention according to claim 2, the paper 4
5 in the direction of rotation of the switching roller 50 by the blade 50a.

Furthermore, in the invention as set forth in claim 3, the switching roller 50 is switched while the previous paper 45a is passing through the switching roller position to change the feeding direction of the next paper 45.

0012

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 shows a schematic configuration of a laser printer equipped with a paper conveying device, which is an embodiment of the present invention. Reference numeral 10 in the figure is the main body of the apparatus, which is placed on an optional dedicated table 11. Inside the device main body 10,
A drum-shaped photoreceptor 12 that rotates clockwise in the figure is provided at the center. Around the photoreceptor 12, a charging unit 13 and an optical writing unit 1 are arranged in order in the rotation direction.
4. Arrange the developing unit 15, transfer unit 16, and cleaning unit 17.

On the other hand, on the right side of the device main body 10 in the figure,
The first paper feed cassette 19 and the second paper feed cassette 20 are removably loaded vertically. The mounting portions of these paper feed cassettes 19 and 20 are provided with paper feed means 24 having a paper feed roller 21, a registration sensor 22, a pair of registration rollers 23, and the like. On the other hand, on the opposite side of the paper feeding means 24 across the transfer unit 16, there is a transport unit 2.
5. The fixing unit 26, paper transport device 27, etc. are arranged in order. The paper transport device 27 includes a branch path 28, a face-down paper discharge path 29, and a double-sided print paper discharge path 31. The face-down paper discharge path 29 is connected to the apparatus main body 10.
It also communicates with a discharge stack section 33 on the apparatus main body 10 via a discharge means 32 provided above. The double-sided print paper discharge path 31 leads to the dedicated table 11.

The dedicated table 11 is provided with a paper reversing means 38 in communication with the above-mentioned double-sided printing paper discharge path 31, and the paper reversing means 38 is also connected to the paper feeding means 24 of the apparatus main body 10 described above. A paper refeeding means 39 is provided. Further, on the right side of the dedicated table 11 in the figure, a mass paper feeder 40 is removably loaded. A paper feed roller 41 and the like are provided at the mounting portion of the mass paper feed device 40.

When the laser printer is operated, the paper feed rollers 21 and 41 are appropriately selected and driven, and paper 45 is fed from the paper feed cassettes 19 and 20 and the mass paper feed device 40. Sequentially send in the direction of arrow A. Then, the registration sensor 22 detects the leading edge of the paper 45, and the sheet 45 stops when it hits the registration roller pair 23, thereby preventing the occurrence of skew.

On the other hand, the surface of the photoreceptor 12 is charged by the charging unit 13 while rotating clockwise in the figure.
Next, an optical writing unit 14 irradiates laser light to form an electrostatic latent image on its surface, and then as it passes through a developing unit 15, the electrostatic latent image is successively visualized. Then, by aligning the image with the resist, the pair of registration rollers 23 described above are driven, and the sheet 45, which has been in contact with the pair of registration rollers 23, is sent out toward the photoreceptor 12. The image on the photoreceptor 12 is then transferred onto the paper 45 in the transfer unit 16. After the transfer, the surface of the photoreceptor 12 is
Cleaning is performed by the cleaning unit 17.

On the other hand, the paper 45 is sent to the fixing unit 26 by the conveying unit 25, where it is fixed, and then conveyed to the branch path 28 by the first pair of conveying rollers 46. When a large amount of paper 45 is to be discharged, the paper 45 is conveyed from the branch path 28 through the face-down paper discharge path 29 by the second pair of conveyance rollers 47, and is then conveyed via the discharge means 32 to the discharge stack section 3.
Send it to 3. Also, if you want to record on the back side,
The feeding direction is switched at the branch path 28, and the sheet is conveyed by the third pair of conveying rollers 48 through the double-sided printing sheet discharge path 31, and guided to the sheet reversing means 38. Then, it is reversed and conveyed again to the paper feeding means 24 through the paper refeeding means 39,
It is also recorded on the back side and discharged onto the discharge stack section 33.

By the way, a switching roller 50 is disposed in the branch path 28 of the paper conveyance device 27, as shown in detail in FIG. The switching roller 50 has thin, soft plate-shaped blades 50a radially arranged on its outer periphery. It is directly connected to a DC motor or a stepping motor (not shown) so that it can instantly switch between normal rotation and reverse rotation, and it is also provided so that it can rotate at a peripheral speed faster than the feeding speed (photoreceptor linear speed) of the paper 45. . Further, when switching the feeding direction of the paper 45, the switching roller 50 is controlled to rotate in a reverse direction while the paper 45a before the paper 45 whose feeding direction is being changed passes through the branch path 28.

As shown in the figure, the paper 45a fixed by the fixing unit 26 is transported by the first pair of transport rollers 46 and sent to the branch path 28, and the leading end of the paper 45a is transferred to the switching roller 50. turn to Then, the leading edge of the paper 45a is guided in the direction of rotation and sent to the face-down paper discharge path 29 by the switching roller 50. At the same time, the blade 50a bends against the paper 45a and guides the paper 45a in the direction of rotation of the switching roller 50 by its elastic force. After the leading end of the paper 45a reaches the second pair of transport rollers 47, when the switching roller 50 is rotated in the reverse direction, the trailing end of the paper 45a slides on the rollers and the rear end of the paper 45a passes. Then, the paper is sent out through the face-down paper discharge path 29 by the second transport roller pair 47. Meanwhile, the next paper 4
5, as shown in FIG. 2, the switching roller 50 is controlled to rotate in the reverse direction while the paper 45a before the paper 45 whose feeding direction is to be switched is passing through the switching roller position. do. Then, the next paper 45 is
The paper 45a is fed in a direction different from that of the previous paper 45a. At this time, similarly to the above, the blade 50a hits the paper 45 and bends, and its elastic force guides the paper 45 in the direction of rotation of the switching roller 50. Then, the paper is sent out through the double-sided printing paper discharge path 31 by the third pair of transport rollers 48.

Therefore, paper can be passed between the paper 45 and the paper 45a as long as there is at least no contact between them, and the linear velocity of the photoreceptor can be made as low as possible. For example, paper interval 10
mm, paper length is 216 mm, print speed is 60P
When calculating the paper feed speed (photoreceptor linear speed) V3mm/s to achieve PM (page/minute), V3
From =60(216+10)/60, V3=226mm
/s, which is 1.2 times faster than the conventional photoreceptor linear velocity of 180 at 30 PPM. In addition, the distance between the switching roller 50 and the second and third conveying roller pairs 47 and 48 is tentatively set to 6.
If it is 0 mm, the switching time of the switching roller is (21
6+10-60)/226=0.73 sec, which is almost the same as 0.8 sec in the conventional case of 30 PPM.

[0022]

From the above, according to the paper conveying device according to claim 1, the switching roller is rotated forward or backward to divide the paper feeding direction into two directions, so that the paper feeding speed can be increased. However, the switching rollers can sort the sheets without pinching them, and therefore the printing speed can be smoothly increased.

Further, according to the paper conveyance device according to the second aspect of the present invention, since the paper is guided in the feeding direction by the blade of the switching roller, the paper can be sorted smoothly and reliably.

Furthermore, according to the paper conveying device of the recording apparatus according to the third aspect, since the next paper is immediately sorted by the switching roller following the previous paper, the gap between the paper sheets can be shortened. Therefore, the printing speed can be smoothly increased without significantly increasing the paper feeding speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a paper conveying device of a laser printer that is an embodiment of the present invention.

FIG. 2 is a state diagram when the switching roller is rotated in the reverse direction while the previous sheet is being conveyed in the sheet conveyance device.

FIG. 3 is a diagram illustrating a state in which the next sheet is being conveyed in the other direction.

FIG. 4 is a schematic diagram of the entire internal mechanism of a laser printer including the paper conveyance device.

FIG. 5 is a schematic configuration diagram of a paper conveyance device in a conventional recording apparatus.

FIG. 6 is an exploded perspective view of the switching claw portion.

FIG. 7 is a state diagram when the switching claw is operated early.

FIG. 8 is a state diagram when the switching claw is operated slowly.

[Explanation of symbols]

28 Branch road 45 Paper 46/47/48 Conveyance roller 50 Switching roller 50a feather

Claims (3)

[Claims] Claim 1: In a paper transport device that transports paper using transport rollers, distributes paper from one direction in a branch path, and sends it out in two directions, a switching roller for distributing the paper in the direction in which the paper is sent out is installed in the branch path.・Paper transport device that can be rotated in reverse. 2. The paper conveyance device according to claim 1, wherein thin, soft plate-like blades are provided radially around the outer periphery of the switching roller. 3. When switching the feeding direction of the paper, the switching roller is controlled to rotate in a reverse direction while the paper preceding the paper whose feeding direction is to be switched passes the position of the switching roller. Item 1. The paper conveyance device according to item 1.