JP2002001938A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which can perform perfect printing by a simple operation. SOLUTION: An image forming device for forming images on a front face and a back face of a paper P comprises a first drum 1 for transporting the paper P while the paper P is closely contacted with a periphery of the drum, a first printing mechanism 2 for ejecting ink to the front face of the paper P to be transferred by the first drum 1, a second rum 5 for transporting the paper P in the state of closely containing the paper P with a periphery of the drum, a second printing mechanism 6 for ejecting ink to the back face of the paper P transported from the second drum 5, and a pair of transportation rollers 9 for transporting the paper P from the first drum 1 the second drum 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus capable of forming an image on both sides of a sheet-like image forming medium.

[0002]

2. Description of the Related Art An image is formed on both sides of a sheet of paper as an image forming medium in the following manner. For example, in an ink-jet printer, first, the first surface of paper is set as a printing surface, and a predetermined image is formed and output. Next, the paper on which the image is formed on the first surface is turned over, and the second surface is set as the printing surface to form and output a predetermined image. As described above, an image can be formed (printed) on both sides of the paper.

[0003]

However, in the above-mentioned prior art, the paper must be passed through the printer twice, and the operation is troublesome. The present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus capable of performing double-sided printing with a simple operation.

[0004]

An image forming apparatus according to the present invention for solving the above-mentioned problems is an image forming apparatus for forming an image on both a first surface and a second surface of a sheet-like image forming medium. A first transport mechanism that transports the image forming medium in a state where the second surface of the image forming medium is in close contact with an outer peripheral portion, and a first transport mechanism that transports the image forming medium transported by the first transport mechanism. A first printing mechanism for discharging the image forming ink to the first surface, and a second transport mechanism for transporting the image forming medium in a state where the first surface of the image forming medium is in close contact with an outer peripheral portion. A second printing mechanism that ejects image forming ink onto the second surface of the image forming medium conveyed by the second conveyance mechanism; and a second printing mechanism that moves from the first conveyance mechanism to the second conveyance mechanism. A third transporter that transports the image forming medium It is characterized in that it comprises and.

The operation and effect of the image forming apparatus having this configuration are as follows. (1) The sheet-shaped image forming medium is conveyed in a state where the second surface of the image forming medium is in close contact with the outer peripheral portion of the first conveying mechanism. At this time, the first surface of the image forming medium faces outward. (2) While the image forming medium is being conveyed by the first conveying mechanism, the image forming ink is discharged onto the first surface by the first printing mechanism.

(3) The third transport mechanism transports the image forming medium having the image formed on the first surface from the first transport mechanism to the second transport mechanism. (4) The image forming medium is transported in a state where the first surface is in close contact with the outer peripheral portion of the second transport mechanism. At this time, the second surface of the image forming medium faces outward. (5) While the image forming medium is being conveyed by the second conveying mechanism, the image forming ink is discharged onto the second surface by the second printing mechanism.

As described above, an image can be formed on both the front and back surfaces of an image forming medium. With respect to the image forming medium, double-sided printing can be performed only by passing the image forming medium once. Therefore, it is possible to provide an image forming apparatus capable of performing double-sided printing with a simple operation.

According to another aspect of the present invention, there is provided an image forming apparatus for forming an image on both a first surface and a second surface of a sheet-like image forming medium. A first transport mechanism that transports the image forming medium while the second surface of the image forming medium is in close contact with an outer peripheral portion;
A printing mechanism that is arranged to face an outer peripheral portion of the first transport mechanism and that discharges image forming ink onto the first surface of the image forming medium transported by the first transport mechanism; A second transport mechanism that transports the image forming medium while the first surface of the medium is in close contact with the outer peripheral portion;
A third transport mechanism that transports the image forming medium from the first transport mechanism to the second transport mechanism, and a third transport mechanism that faces the outer peripheral portion of the second transport mechanism after the image forming process on the first surface is completed. A moving mechanism for moving the printing mechanism so as to cause the printing mechanism to eject the image forming ink to the second surface of the image forming medium conveyed by the second conveying mechanism. It is characterized by having done.

The operation and effect of the image forming apparatus having this configuration are as follows. (1) The sheet-shaped image forming medium is conveyed in a state where the second surface of the image forming medium is in close contact with the outer peripheral portion of the first conveying mechanism. At this time, the first surface of the image forming medium faces outward. (2) While the image forming medium is being conveyed by the first conveying mechanism, the image forming ink is discharged onto the first surface by the printing mechanism.

(3) The third transport mechanism transports the image forming medium having the image formed on the first surface from the first transport mechanism to the second transport mechanism. (4) On the other hand, the printing mechanism is moved from a position facing the outer peripheral portion of the first transport mechanism to a position facing the outer peripheral portion of the second transport mechanism.

(5) The image forming medium is conveyed in a state where the first surface is in close contact with the outer peripheral portion of the second conveying mechanism. At this time, the second surface of the image forming medium faces outward. (6) While the image forming medium is transported by the second transport mechanism, the second transport mechanism moves the image forming medium to the second transport mechanism.
The image forming ink is ejected onto the surface.

As described above, an image can be formed on both sides of an image forming medium. With respect to the image forming medium, double-sided printing can be performed only by passing the image forming medium once. Therefore, it is possible to provide an image forming apparatus capable of performing double-sided printing with a simple operation.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Structure of First Embodiment> A preferred first embodiment of an image forming apparatus according to the present invention will be described with reference to FIG. This image forming apparatus uses a sheet of paper P
A first drum 1 (or a first rotating body: corresponding to a first transport mechanism) for transporting (corresponding to an image forming medium) tightly wound around the outer peripheral portion; A first printing mechanism 2 for printing an image on the first surface of the paper P wound around, a first charging roller 3 that contacts an outer peripheral portion of the first drum 1, and a first counter electrode roller 4. It has. The transport direction of the paper P is indicated by a thick arrow.

Further, on the downstream side of the first drum 1, a second drum 5 (or a second rotating body: corresponding to a second transport mechanism) for transporting the paper P in a state of being closely wound around the outer peripheral portion. A second printing mechanism 6 for printing an image on the second surface of the paper P wound around the second drum 5, and a second charging roller 7 that contacts an outer peripheral portion of the second drum 5. , A second counter electrode roller 8. In addition, a transport roller pair 9 (corresponding to a third transport mechanism) is provided in a transport path between the first drum 1 and the second drum 5.

The first drum 1 transports the paper P in close contact with its outer peripheral portion by electrostatic attraction. The first charging roller 3 charges the first drum 1 to +. The first drum 1 has an insulating film formed on the outer periphery of a metal cylindrical portion having a diameter of about 200 mm. First
The drum 1 is rotationally driven in a counterclockwise direction in FIG. 1 by a drive motor (not shown). The counter electrode roller 4 is negatively charged or grounded to GND.

The first printing mechanism 2 is a so-called ink jet printer head, and includes a yellow head 2a, a magenta head 2b, and a cyan head 2c. ), Magenta (M), and cyan (C) inks. The distance between each of the heads 2a, 2b, 2c and the outer peripheral portion of the first drum 1 is set to about 1 mm.

A detaching member 10 is provided on the outer peripheral portion of the first drum 1 downstream of the first printing mechanism 2, and the paper P on which an image is formed on the first surface is applied to the outer peripheral portion of the first drum 1. Let go.

The second drum 5 and the second printing mechanism 6 have the same configuration as the first drum 1 and the first printing mechanism 2.
The second drum 5 is driven to rotate clockwise by a drive motor (not shown). The detachment member 11
The paper P on which an image is formed on the second surface is separated from the outer peripheral portion of the second drum 5.

The transport roller pair 9 transports the paper P on which an image has been formed on the first surface by the first printing mechanism 2 toward the second drum 5. Further, each ink discharged from the first printing mechanism 2 is dried and fixed by heat. Therefore, the transport roller pair 9 also functions as a fixing roller pair. However,
If the ink has quick drying properties, the function as a fixing roller is not required.

<Operation of First Embodiment> Next, the operation of the image forming apparatus shown in FIG. 1 will be described. First, the paper P is transported from the right side in FIG. The paper P is fed while being held between the first drum 1 and the first counter electrode roller 4. The first drum 1 rotates counterclockwise, and also rotates (conveys) the paper P electrostatically attracted to the outer peripheral portion of the first drum 1. Based on the image data sent to the first printing mechanism, an amount of ink corresponding to the image data is applied from each of the heads 2a, 2b, 2c to the first of the paper P.
Discharge on the surface. A digital image is sequentially formed line by line in dot units by discharging ink.

When the leading end of the paper P reaches the position of the separating member 10, the leading end of the paper P separates from the first drum 1. When the leading end of the paper P is nipped by the transport roller pair 9, the paper P is transported by the transport roller pair 9 and also fixes the image formed on the first surface.

Next, when the paper P is transported,
The paper P is sandwiched between the second drum 5 and the second counter electrode roller 8 and is conveyed while being electrostatically attracted to the outer peripheral portion of the second drum 5. In the second drum 5, the paper P is transported such that the second surface of the paper P is on the outside, contrary to the case of the first drum 1. Based on the image data sent to the second printing mechanism 6, each head 6
The amount of ink corresponding to the image data from a, 6b, and 6c is discharged onto the second surface of the paper P.

When the leading end of the paper P reaches the position of the separating member 11, the leading end of the paper P separates from the second drum 5. Thereafter, the image formed on the second surface is fixed by a fixing roller (not shown), and is discharged as a finished print outside the image forming apparatus.

<Structure of Second Embodiment> Next, a preferred second embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. In the first embodiment, the first printing mechanism 2 and the second printing mechanism 6 are provided, but in the second embodiment, there is one printing mechanism. Hereinafter, the points different from the first embodiment will be mainly described.

Drums 1, 5, printing mechanism 2, charging rollers 3, 7, counter electrode rollers 4, 8, separating members 10, 11,
The transport roller pair 9 has the same configuration. However, the second charging roller 7 in contact with the second drum 5
The counter electrode roller 8 can be retracted to the position indicated by the broken lines 7 'and 8'. Also, the detaching member 11
It is possible to retreat to a broken line position indicated by reference numeral 11 '.

Next, the moving mechanism 20 for moving the printing mechanism 2 from a position facing the outer peripheral portion of the first drum 1 to a position facing the outer peripheral portion of the second drum 5 will be described. The moving mechanism 20 includes a cam groove 21 and a cam groove 2.
1, a support 23 to which the bearing 22 is attached and supported, a moving body 24 having a fitting groove 24a into which the bearing 22 is fitted, and a moving body 2
4 is provided with a belt conveyor mechanism 25 for moving the belt 4 in the horizontal direction.

The cam groove 21 is provided for each head 2 of the printing mechanism 2.
The printing mechanism 2 is moved so that a, 2b, and 2c do not interfere with the outer peripheral portion of the first drum 1. That is, the cam groove 21
Of the heads 2a, 2b, 2c
Is once lifted upward in FIG. 2 and then moved in the horizontal direction. Further, when the printing mechanism 2 is set on the outer peripheral portion of the second drum 5, the inclined portion 21a is formed so as to perform the reverse movement. The moving mechanism 2
The configuration of 0 is not limited to that shown in FIG.

<Operation of Second Embodiment> Next, the operation of the image forming apparatus shown in FIG. 2 will be described. First, the paper P is transported from the right side in FIG. The paper P is fed while being held between the first drum 1 and the first counter electrode roller 4. The first drum 1 rotates counterclockwise, and also rotates (conveys) the paper P electrostatically attracted to the outer peripheral portion of the first drum 1. Based on the image data sent to the first printing mechanism, an amount of ink corresponding to the image data is applied from each of the heads 2a, 2b, 2c to the first of the paper P.
Discharge on the surface. A digital image is sequentially formed line by line in dot units by discharging ink.

When the leading end of the paper P reaches the position of the separating member 10, the leading end of the paper P separates from the first drum 1. When the leading end of the paper P is nipped by the transport roller pair 9, the paper P is transported by the transport roller pair 9 and also fixes the image formed on the first surface.

On the other hand, the belt conveyor mechanism 25 is driven to move the moving body 24 to the left in FIG. Accordingly, the printing mechanism 2 also moves to the left, and is moved from a position facing the outer peripheral portion of the first drum 1 to a position facing the outer peripheral portion of the second drum 5.

Next, when the paper P is transported,
The paper P is sandwiched between the second drum 5 and the second counter electrode roller 8 and is conveyed while being electrostatically attracted to the outer peripheral portion of the second drum 5. In the second drum 5, the paper P is transported such that the second surface of the paper P is on the outside, contrary to the case of the first drum 1. At this time, the detaching member 11 is retracted to the position indicated by the broken line. Therefore, the paper P is rotated clockwise as it is sucked by the second drum 5 to a position facing the printing mechanism 2 (shown by a broken line) which has been moved by the moving mechanism 20. It is transported. Then, based on the image data sent to the printing mechanism 2,
An amount of ink corresponding to the image data is ejected from the heads 2a, 2b, 2c onto the second surface of the paper P.

The paper P on which the image has been formed is subsequently conveyed while being wound on the second drum 5.
At this time, the second charging roller 7 and the second opposing electrode roller 8 have retracted to the positions shown by the broken lines. This allows
The paper P is further conveyed by the second drum 5 subsequently. At this time, the detaching member 11 has returned from the position shown by the broken line to the position shown by the solid line. When the leading end of the paper P reaches the position of the detaching member 11, the leading end of the paper P separates from the second drum 5. . Thereafter, the image formed on the second surface is fixed by a fixing roller (not shown), and is discharged as a finished print outside the image forming apparatus.

As described above, in both the first and second embodiments, an image can be formed on both sides of the paper P by passing the paper P only once in the image forming apparatus (so-called one pass). The operation is simpler than in the past.

<Another Embodiment> (1) The type of image forming medium is not limited to paper,
For example, special paper for inkjet may be used. (2) The close winding of the image forming medium around the drums 1 and 5 is not limited to electrostatic attraction, but may be performed by other methods, for example,
You may make it contact with many rollers, guide members, etc.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an image forming apparatus according to a first embodiment.

FIG. 2 is a diagram illustrating a configuration of an image forming apparatus according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st drum 2 1st printing mechanism 2a yellow head 2b magenta head 2c cyan head 5 2nd drum 6 2nd printing mechanism 20 moving mechanism P paper

Claims (2)

[Claims] A first surface and a second surface of a sheet-like image forming medium;
An image forming apparatus for forming an image on both sides of a surface, a first transport mechanism for transporting the image forming medium in a state where the second surface of the image forming medium is in close contact with an outer peripheral portion; A first printing mechanism for discharging image forming ink onto the first surface of the image forming medium conveyed by a first conveying mechanism, and a state in which the first surface of the image forming medium is in close contact with an outer peripheral portion A second transport mechanism for transporting the image forming medium; a second printing mechanism for discharging image forming ink onto the second surface of the image forming medium transported by the second transport mechanism; An image forming apparatus comprising: a third transport mechanism configured to transport the image forming medium from the first transport mechanism to the second transport mechanism. 2. A first surface and a second surface of a sheet-shaped image forming medium.
An image forming apparatus for forming an image on both sides of a surface, a first transport mechanism that transports the image forming medium in a state where the second surface of the image forming medium is in close contact with an outer peripheral portion, A printing mechanism that is arranged to face an outer peripheral portion of the first transport mechanism and that discharges image forming ink onto the first surface of the image forming medium transported by the first transport mechanism; A second transport mechanism for transporting the image forming medium in a state where the first surface is in close contact with an outer peripheral portion; and a second transport mechanism for transporting the image forming medium from the first transport mechanism to the second transport mechanism. And a moving mechanism for moving the printing mechanism so as to be opposed to an outer peripheral portion of the second conveying mechanism after the image forming process on the first surface is completed, and conveyed by the second conveying mechanism. The image form With respect to the second surface of the medium, the image forming apparatus characterized by being configured to eject ink for image forming by the printing mechanism.