JPH10319657A - Paper feeder for electrophotographic printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically enhance printing quality by improving registering accuracy. SOLUTION: In an electrophotographic printer for attaining printing by a web system, paper feeder parts 3 and 3' are provided on the upstream and downstream sides of a printer part 2 respectively. Simultaneously, motors 9 and 9' are arranged exclusively on the feeding rollers 7 and 7' of the feeder parts 3 and 3', respectively. The feeding rollers 7 and 7' are independently driven by the motors 9 and 9'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a paper feeder for stabilizing the shape of a web running on a printing device provided in an electrophotographic printing machine.

[0002]

2. Description of the Related Art FIG. 6 is a diagram for explaining the structure and functions of a general paper feeder in an electrophotographic printing machine. As shown in FIG. 6, the illustrated electrophotographic printing machine is roughly composed of a web supply unit 51, a printing unit 52, a paper feed unit 53, a cutting unit 54, a paper discharge unit 55, and the like. .

[0003] The web supply unit 51 includes a roll-shaped web 56.
Are supported by pinching and supporting from both shaft end sides, and a brake device 58 for braking the rotation is disposed at a portion of the support shaft 57. Then, the printing unit 5 in the next step
Reference numeral 2 denotes a unit for performing predetermined printing on the web 59 continuously supplied from the web supply unit 51. Before and after the printing device section 52, guide rollers 60a,
60b and 60c are provided.

A paper feeder 53 controls the speed of a feed roller 62 by a motor (electric motor) 61.
The web 59 is conveyed at a running speed synchronized with the printing speed in the printing unit 52 by the frictional force of the web 59 wound on the outer peripheral surface of the feed roller 62. Before and after the feed roller 62, rollers 63a, 63
3b are juxtaposed. Here, reference numeral 64 denotes a fixing device,
θ indicates the winding angle of the web 59, and the winding angle is θ <18.
It is set to 0 °. Further, the paper discharge unit 55 is a unit that receives the sheets 65 cut in a direction perpendicular to the traveling of the web 59 in the cutting device unit 54 in the previous process, and sequentially stacks the sheets 65, and the discharge table 66 of the paper discharge unit 55. Is continuous depending on the number (thickness) of the sheets 65 dropped and input,
Alternatively, it descends intermittently, and the height of the uppermost portion of the seat 65,
That is, the head is configured (controlled) so that the head is substantially constant. Incidentally, v ₁ paper feed speed in the printer unit 52, v ₂
Indicates the peripheral speed of the feed roller 62.

[0005] Under the above structure, the rolled paper 56 attached to the web supply unit 51 is rewound in the direction of the arrow in FIG. Subsequently, the printed web 59 is transferred to the fixing device 64 via the guide roller 60b.
After being wound around the feed roller 62, it is sent to the cutting device 54. Thereafter, the sheets 65 cut by the cutting device unit 54 are output one by one to the discharge unit 5.
5 and is stacked on the discharge table 66 of FIG.

[0006]

Next, problems of the paper feeding device 53 will be described. That is, in the conventional paper feeder in the electrophotographic printing machine, only one set is provided downstream of the printing unit 52, and the web 59 is provided.
The pulling force in the sheet conveying direction using the frictional force generated by the winding of the feed roller 62 defined by the rollers 63a and 63b in the paper feeding device unit 53, and the web 56 in the web supply unit 51 Supported shaft 5
A predetermined tension is applied to the web 59 fed to the printing unit 52 by a braking force (back tension on the sheet) acting on the sheet 7. However, in these types of driving devices that control the speed on the one hand and apply a constant tension on the other hand, the slip between the rollers between the printing device units 52 and the feed roller 62, changes in the paper feed speed due to temperature changes, etc. There is a problem in that there is a misregistration between the first color and the final color in multicolor printing.

The present invention has been made in view of such circumstances, and has as its object to provide a paper feeder for an electrophotographic printing machine capable of improving register accuracy and greatly improving print quality. Is to provide.

[0008]

SUMMARY OF THE INVENTION In order to solve the problems of the prior art, according to the present invention, in an electrophotographic printing machine for printing by a web system, paper is provided on an upstream side and a downstream side of a printing unit, respectively. In addition to providing a feeder unit,
A motor is exclusively provided for each of the feed rollers of each of the paper feeder units, and the respective feed rollers are independently driven by the motors.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

FIG. 1 is a schematic structural explanatory view of a paper feeder of an electrophotographic printing machine according to an embodiment of the present invention. As shown in FIG. 1, the electrophotographic printing machine according to the embodiment of the present invention includes a web supply unit 1, a printing unit 2, paper feed units 3, 3 ', a cutting unit 4, a paper discharge unit 5, and the like. The basic configuration of the electrophotographic printing machine is the same as that described in the section of the related art. The embodiment of the present invention proposes a paper feeder unit 3 that stabilizes the form of the web 6 running on the printing device unit 2 and improves registration accuracy.

The basic structure of the embodiment of the present invention is as follows.
As shown in FIG. 1, the upstream and downstream
It is characterized in that the paper feed units 3 and 3 'are arranged so that they can be driven independently of each other. The paper feed units 3, 3 'are provided with feed rollers 7, 7' and rollers 8a, which are arranged in front of and behind the feed rollers 7, 7 '.
8a ', 8b and 8b', and motors 9 and 9 'dedicated to the feed rollers 7 and 7', respectively. Therefore, the paper feeder units 3, 3 'are driven by the frictional force between the outer peripheral surfaces of the feed rollers 7, 7' and the web 6 wound therearound through the rotation of the feed rollers 7, 7 'by the motors 9, 9'. , The web 6 is conveyed.

In the paper feed units 3, 3 'on the upstream and downstream sides of the printing unit 2, the position of the rollers 8a, 8a', 8b, 8b 'with respect to the feed rollers 7, 7' depends on the front and rear positions. , the web 6 comes into contact with the outer peripheral surface of the feed roller 7, 7 'have a minimum wound angle theta ₀ required to inhibit slippage of the paper. Here, the winding angle is set to θ ₀ > 180 °. Moreover, the paper feed units 3, 3 'are provided with the feed rollers 7,
The operation is independently controlled by independent motors 9 and 9 'for driving the rotation of 7'. Further, a motor 9, which drives the feed rollers 7, 7 ',
9 'are each configured to perform speed control.

The web supply unit 1 is constructed by sandwiching and supporting a roll-shaped web 10 from both shaft ends of a support shaft 11. Further, the printing device unit 2 in the next process
Is configured to perform predetermined printing on the web 6 continuously supplied from the web supply unit 1. Guide rollers 12a, 12b, and 12c are provided before and after the printing device section 2, and guide rollers 12b and 1b on the downstream side are provided.
A fixing device 13 is provided between 2c. further,
The paper discharge unit 5 is a unit that receives the sheets 14 cut in a direction perpendicular to the traveling of the web 6 in the cutting device unit 4 in the preceding process and sequentially stacks the sheets 14. The paper discharge table 15 of the paper discharge unit 5 is The sheet 14 is continuously or intermittently lowered according to the number (thickness) of the sheets 14 dropped and thrown, so that the height of the uppermost portion of the sheet 14, that is, the drop is made substantially constant (control). Incidentally, v ₁ denotes the peripheral speed of the feed roller 7, v ₂ is the peripheral speed of the feed rollers 7 ', respectively.

In the electrophotographic printing machine having the above-described configuration,
The roll-shaped web 10 mounted on the web supply unit 1 is rewound in the direction of the arrow in FIG. 1, is wound around the guide roller 12 a via the upstream paper feed unit 3, and is then carried into the printing unit 2. Is done. Then, after predetermined printing is completed in the printing device unit 2, the guide roller 12b, the fixing device 13, and the guide roller 12c are wound and sent to the cutting device unit 4 via the downstream paper feed unit 3 '. . Thereafter, the sheets 14 cut by the cutting device unit 4 fall one by one onto the discharge table 15 of the discharge unit 5 and are stacked, as in the conventional example.

[0015] The paper feeder according to the embodiment of the present invention comprises:
Since the peripheral velocities v ₁ and v ₂ of the feed rollers 7 and 7 ′ in the paper feeding units 3 and 3 ′ provided upstream and downstream of the printing unit 2 can be independently adjusted and set, FIG. The peripheral speed v ₂ of the middle and downstream feed rollers 7 ′ is set slightly higher (v ₂ > v ₁ ) than the peripheral speed v ₁ of the upstream feed roller 7. wherein a change of the paper feed speed generated by a change in diameter due to diameter difference and the temperature variation of the feed rollers 7, 7 'v ₂ and v ₁
By setting the speed ratio appropriately, the sheet feed amount can be controlled to be constant, and high-precision printing with little misregistration has been made possible.

FIG. 2 illustrates an example of the structure of the paper feeding means of another paper feeding device 23. FIG. 2 illustrates a pair of pressurizing devices 16 in association with the feed roller 7.
a and 16b are provided. These pair of pressurizing devices 1
Reference numerals 6a and 16b are located at both ends in the width direction of the paper feeder unit 23 and are configured to operate synchronously. Is being worn. This pressing roller 17
It is configured to engage with the feed roller 7 via the running web 6 and to rotate around.

In the paper feeder unit 23 having the above-described structure,
As shown in FIG. 2, the pressing roller 17 can be brought into and out of contact with the feed roller 7 through expansion and contraction of the pressing devices 16a and 16b. Therefore, the web 6 can be driven without slipping by pressing the web 6 against the feed roller 7 with the pressing roller 17.

FIG. 3 shows still another paper feed unit 33.
A configuration example of the paper feeding means will be described. In the example illustrated in FIG. 3, two sets of feed rollers 7a and 7b are provided in parallel, and the web 6 is configured to be wound around each of the feed rollers 7a and 7b and run. In addition, the feed rollers 7a and 7b are driven to rotate in conjunction with each other. Here, the winding angle θ of the web 6 is θ = θa
+ Θb. The paper feed unit 3
As the third paper feeding means, a type in which three or more sets of feed rollers 7 are provided in parallel (not shown) is also conceivable.

In the paper feeder unit 33 having the above configuration,
As shown in FIG. 3, the web 6 is divided into two sets of feed rollers 7.
a, 7b, the web 6 can be wound at a wide angle θ, and the contact area can be increased, so that the frictional resistance of the web 6 to the feed roller 7 increases and the slip limit increases. Becomes possible.

FIGS. 4 and 5 illustrate still another example of the structure of the paper feeding means of the paper feeding device 43. FIG. 4 and 5 are configured by incorporating a speed reducer 18 between the feed roller 7 and a motor (electric motor) 9 for rotating the feed roller 7. As such a speed reducer 18, various types and speed reduction ratios can be adopted.

In the paper feeder section 43 having the above configuration,
As shown in FIGS. 4 and 5, the rotational speed of the motor 9 for rotating the feed roller 7 can be increased by incorporating the speed reducer 18, so that the peripheral speed of the feed roller 7 is more finely adjusted (controlled). It becomes possible.

In the paper feeder according to the embodiment of the present invention, since the paper feeders 3, 3 'are disposed upstream and downstream of the printing unit 2, respectively, the feed rollers 7, 7' are provided. The web 6 is prevented from slipping with respect to, and the feed amount (ratio) of the web 6 can be reliably secured by the feed roller 7.
Upstream feed roller 7 and downstream feed roller 7 '
By finely controlling both the peripheral velocities v ₁ and v ₂ , the paper feed speed of the web 6 traveling on the printing device unit 2 can be kept constant. Therefore, in the electrophotographic printing machine equipped with the paper feeding device of the present embodiment, the register accuracy is improved, and the printing quality can be greatly improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes may be made without departing from the gist of the present invention. What you get. In addition, the paper feed units 3, 3 ', 23, 33, 43 illustrated in FIGS.
It is possible to adopt various methods such as not only installing the same type of apparatus on the upstream side and the downstream side of the printing apparatus section 2 but also installing the apparatuses in an appropriate combination.

[0024]

As described above, the paper feeder of the electrophotographic printing machine according to the present invention is provided with the paper feeders on the upstream side and the downstream side of the printing unit, respectively. Since the motors are provided exclusively for the rollers and the respective feed rollers are independently driven by the motors, it is possible to prevent the web from slipping with respect to the feed rollers, and the webs can be reliably formed by the feed rollers. Feed amount can be secured. In addition, by finely controlling the peripheral speeds of the upstream and downstream feed rollers together, it is possible to maintain a constant paper feed speed of the web traveling on the printing device, thereby improving registration accuracy and greatly improving print quality. Improvement can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of a paper feed unit of an electrophotographic printing machine according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an example of a paper feeding unit of the paper feeding device unit.

FIG. 3 is an explanatory view showing another example of the paper feeding means of the paper feeding device.

FIG. 4 is an explanatory view showing still another example of the paper feeding means of the paper feeding device.

FIG. 5 is a view taken in the direction of arrow A in FIG. 4;

FIG. 6 is an explanatory diagram showing a schematic configuration of a paper feed unit of a conventional electrophotographic printing machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Web supply part 2 Printing device part 3, 3 'Paper feeder part 4 Cutting device part 5 Paper discharge part 6 Web 7, 7' Feed roller 8a, 8b, 8a ', 8b' Roller 9, 9 'Motor 10 Roll shape Web paper 11 Support shaft 12 Guide roller 13 Fixing device 14 Sheet 15 Discharge table 16 Pressure device 17 Press roller 18 Reducer 23, 33, 43 Paper feed unit θ, θ ₀ Web winding angle

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Norifumi Tasaka 4-6-22 Kannonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima In the Hiroshima Research Laboratory of Mitsubishi Heavy Industries, Ltd.

Claims (6)

[Claims] In an electrophotographic printing machine for printing by a web system, paper feed units are provided on an upstream side and a downstream side of a printing unit, respectively, and a motor is dedicated to a feed roller of each of the paper feed units. A feeder for an electrophotographic printing machine, wherein the feed rollers are independently driven by the motor. 2. The paper feeding means of the paper feeding device is configured to wind a running web around an outer peripheral surface of the feed roller by a feed roller and rollers arranged before and after the feed roller. The paper feeder of an electrophotographic printing machine according to claim 1, wherein: 3. A paper feeding means of the paper feeding device section is provided with a pressurizing device in association with a feed roller, and a press roller fixed to the pressurizing device is wound around the feed roller. The paper feeding device of an electrophotographic printing machine according to claim 1, wherein the web is configured to be pressed against the feed roller to make contact therewith. 4. A paper feeding means of the paper feeding device section, wherein two or more sets of feed rollers are arranged in parallel, and the web is run by winding the feed rollers together. The paper feeder of an electrophotographic printing machine according to claim 1, wherein 5. The electrophotographic apparatus according to claim 1, wherein the paper feed unit of the paper feed unit is configured by incorporating a speed reducer in a motor that is a rotation driving unit of the feed roller. Paper feeder for a printing system. 6. The paper feeding device according to claim 1, wherein the paper feeding device of the paper feeding device section is configured by combining any one of the paper feeding devices described in claim 2 to 5. Paper feeder for electrophotographic printing machines.