JP2004025800A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus in which a carriage, and the like, are protected against damage without requiring a troublesome operation against jamming, or the like. <P>SOLUTION: A coil spring 50 has an upper end secured to the lower end part of a plate 46 for supporting a roll 42 rollably, and a lower end part secured to a part of the body 40 of a carriage 20 lower than the axis 48. The body 40 of the carriage 20 is thereby urged by the coil spring 50 to turn round a lower guide rail 17 in the direction opposite to a direction shown by the arrow D. When a pinch roller 26 is lifted to separate from a drive roller 24, the pinch roller 26 touches the body 40 of the carriage 20. Consequently, the body 40 of the carriage 20 turns slightly round the lower guide rail 17 in the direction shown by the arrow D while resisting against the urging force of the coil spring 50. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus that forms an image by discharging ink from a print head mounted on a carriage onto a recording medium.
[0002]
[Prior art]
2. Description of the Related Art As one of output devices of computers and workstations, there is known an ink-jet type image forming apparatus that forms an image by discharging ink onto a recording medium such as recording paper. The inkjet image forming apparatus generally includes a print head having a plurality of nozzles for discharging ink, a carriage mounted with the print head and reciprocating in a main scanning direction, and a direction orthogonal to the main scanning direction. (A sub-scanning direction and a recording medium transport direction).
[0003]
When forming an image on a recording medium with the above-described ink jet type image forming apparatus, the recording medium being conveyed by the recording medium conveying apparatus is temporarily stopped, and the image is formed while the carriage is reciprocated in the main scanning direction. Ink is selectively ejected from a plurality of nozzles based on an image signal carrying information, and an image for one band is formed in a portion of the recording medium located in an image forming area facing an outlet (ink ejection port) of the nozzle. I do. Thereafter, the recording medium is conveyed by the width of one band and stopped, and again, while the carriage is reciprocated in the main scanning direction, ink is ejected from the nozzles based on the image signal, and the ink is discharged to the image forming area of the recording medium. An image is formed on a newly located portion. An image is formed on a recording medium by repeating such an operation.
[0004]
Incidentally, as one of the above-described recording medium conveying apparatuses, a pair of conveying rollers including a driving roller and a pinch roller is known. The pair of transport rollers are disposed below and in the vicinity of the carriage, and transport the recording medium to an image forming area below the carriage (below the print head). Usually, the pair of transport rollers have a drive roller located below the pinch roller, and are configured so that the pinch roller can be lifted and separated from the drive roller. Further, in order to reduce the trailing margin of the recording medium, it is necessary to bring the print head and the pinch roller close to each other.
[0005]
However, when the print head and the pinch roller are close to each other, when the pinch roller moves up, it collides with the carriage or the print head. In order to prevent such a collision, a lock mechanism is provided for preventing the pinch roller from being inadvertently raised.
[0006]
[Problems to be solved by the invention]
When the above-described lock mechanism is provided, the pinch roller cannot be lifted unless the lock mechanism is released. For this reason, when a paper jam (jam) occurs in the pair of transport rollers or in the vicinity thereof, the carriage is moved out of the image forming area, and then the lock mechanism is released to raise the pinch roller. Move away from drive roller. Therefore, the operation becomes troublesome. However, when this troublesome operation is not performed, the pinch roller may collide with the carriage or the print head and be damaged.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image forming apparatus capable of preventing a carriage or the like from being damaged without performing a troublesome operation for jam clearance or the like.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an image forming apparatus according to the present invention includes a carriage mounted with a print head for ejecting ink and scanning in a predetermined main scanning direction, and a pair of paper conveying a recording medium below the carriage while nipping the recording medium. Forming a recording medium by conveying the recording medium below the carriage by the pair of conveying rollers and discharging the ink from the print head onto the recording medium while scanning the carriage in the main scanning direction. In the device,
(1) The pair of transport rollers are disposed below the carriage and come into contact with and separate from each other;
(2) The carriage is configured such that a transport roller closer to the carriage out of the pair of transport rollers rises apart from the other transport roller and comes into contact with the carriage, so that the impact in the direction of relaxing the contact is reduced. It is characterized by moving.
[0009]
here,
(3) a lower guide rail fitted with the lower portion of the carriage and fixed to the image forming apparatus main body and extending in the main scanning direction;
(4) The carriage, which is guided by the lower guide rail and scans in the main scanning direction, and moves in the relaxation direction by rotating about the lower guide rail as a rotation center. It may be.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0011]
With reference to FIG. 1, an inkjet type plotter which is an example of the image forming apparatus of the present invention will be described.
[0012]
FIG. 1 is a perspective view showing a schematic configuration of an ink jet type plotter.
[0013]
The plotter 10 includes a platen 14 on which the recording paper 12 conveyed in the direction of arrow A is placed. Above the platen 14, an upper guide rail 16 and a lower guide rail 17 are extended in parallel with the platen 14. A carriage 20 that reciprocates (scans) in the directions of arrows B and C (the direction orthogonal to the direction of arrow A) by means of a motor (not shown) and a belt 18 is a slide bearing (not shown) on these guide rails 16 and 17. Zu) is attached through. The lower portion of the carriage 20 is fitted into the lower guide rail 17, and the carriage 20 rotates about the lower guide rail 17 as a rotation center, as described later. Further, a pair of rollers 42 and 44 that rotate while sandwiching the upper guide rail 16 are rotatably fixed to the carriage 20.
[0014]
The carriage 20 has four print heads 22K (black), 22C (cyan), 22M (magenta), and 22Y (yellow) having ink discharge ports (nozzle outlets, not shown) for discharging ink. Have been. In front of the ink ejection port is an image forming area 23 where an image is formed. Ink is ejected from the ink ejection port to a portion of the recording paper 12 that is located in the image forming area 23, whereby an image is formed on this portion.
[0015]
In addition, ink is forcibly sucked from the nozzles in an area of the movable area of the carriage 20 distant from the image forming area 23, and the ink supply paths and the nozzles formed in the print heads 22 </ b> K, 22 </ b> C, 22 </ b> M, and 22 </ b> Y are formed. A recovery device 30 is disposed to clean the print heads 22K, 22C, 22M, and 22Y so as to set the ink discharge state of the print heads to the initial discharge state.
[0016]
The recovery device 30 is provided with four rubber caps 32K, 32C, 32M, and 32Y that cover the ink discharge ports of the four print heads 22K, 22C, 22M, and 22Y. One end of a waste ink tube (not shown) is connected to each of the caps 32K, 32C, 32M, and 32Y, and the other end of the waste ink tube is connected to a suction pump (not shown). The four caps 32K, 32C, 32M, and 32Y are fixed to the cap base 32.
[0017]
In forming an image on the recording paper 12 such as a roll paper, the recording paper 12 is placed on the platen 14 and a part of the outer peripheral surface is exposed from an opening (not shown) formed in the platen 14. The recording paper 12 is conveyed by rotating the driving roller 24 by a conveyance motor (not shown) while nipping the recording paper 12 by the driven roller 24 and the pinch roller 26 for pressing both ends of the recording paper 12 from above. . The carriage 20 is reciprocated in the directions of arrows B and C above the recording paper 12 based on an image signal carrying image information transmitted from a head control unit (not shown) to the print heads 22K, 22C, 22M and 22Y. The ink is ejected from the nozzles to form an image on a portion of the recording paper 12 located in the image forming area 23. The drive roller 24 and the pinch roller 26 are an example of a pair of transport rollers according to the present invention.
[0018]
The above-described pinch roller 26 is configured to move up and away from the drive roller 24. Further, the pinch roller 26 moves up and comes into contact with the carriage 20, so that the carriage 26 moves in a direction to reduce the impact due to the contact. Such a configuration will be described with reference to FIGS.
[0019]
FIG. 2 is a side view showing a part of the carriage in a state where printing is possible. FIG. 3 is a side view in which a part of the carriage slightly rotated about the lower guide rail as a rotation center is cut away. In these drawings, the same components as those shown in FIG. 1 are denoted by the same reference numerals.
[0020]
The lower portion of the carriage 20 is fitted into the lower guide rail 17, and the entire carriage 20 rotates in the direction of arrow D around the lower guide rail 17 as a rotation center. On the other hand, a pair of rollers 42 and 44 for holding the upper guide rail 16 are rotatably fixed to the upper portion of the carriage, as described above. When the carriage 20 scans in the main scanning direction, the pair of rollers 42, 44 sandwich the upper guide rail 16, and the upper guide rail 16 and the lower guide rail 17 guide the carriage 20 in the main scanning direction.
[0021]
The carriage 20 is provided with a roller support plate 46 for rotatably fixing the rollers 42. The roller support plate 46 has a shape like a series of “L” characters, and an intermediate portion thereof is rotatably connected to a short shaft 48. The shaft 48 is fixed to an upper part of the main body 40 of the carriage 20. The shaft 48 is located slightly below the upper guide rail 16 and extends in the main scanning direction.
[0022]
The roller 42 is rotatably fixed to the upper end of the roller support plate 46. The upper end of the coil spring 50 is fixed to the lower end of the roller support plate 46. The lower end of the coil spring 50 is fixed to a portion of the main body 40 of the carriage 20 below the shaft 48. Therefore, the main body 40 of the carriage 20 is urged by the coil spring 50 so as to rotate about the lower guide rail 17 in the direction opposite to the direction of arrow D (clockwise in FIGS. 2 and 3).
[0023]
When an image is formed by ejecting ink from the print head 22 to a recording medium, as shown in FIG. 2, the pinch roller arm 54 is urged clockwise about the shaft 53 by the pinch roller pressing spring 55. The pinch roller 26 is in contact with the drive roller 24. At this time, the cam 52 is separated from the pinch roller arm 54. By lowering the cam 52 and rotating the pinch roller arm 54 counterclockwise about the shaft 53, the pinch roller 26 separates from the drive roller 24 by overcoming the urging force of the pinch roller pressing spring 55. In this case, the pinch roller 26 contacts the main body 40 of the carriage 20, as shown in FIG. Due to this contact, the main body 40 of the carriage 20 is opposed to the urging force of the coil spring 50 in the direction of arrow D (counterclockwise in FIG. 3, which is an example of a relaxing direction according to the present invention) around the lower guide rail 17. ) To rotate a little. With this rotation, the roller 44 separates from the upper guide rail 16, and the roller support plate 46 slightly rotates clockwise about the shaft 48 so that the roller 42 is slightly inclined. Further, the coil spring 50 is extended by rotating the carriage 20 in the direction of arrow D.
[0024]
Even if the pinch roller 26 contacts the carriage 20 or the print head 22 as described above, the impact due to this contact is reduced. Accordingly, when the carriage 20 is positioned above the pinch roller 26, even if the pinch roller 26 is raised, the carriage 20, the print head 22, and the pinch roller 26 are not damaged.
[0025]
As a result, even if the pinch roller 26 is arranged near the print head 22 in order to reduce the trailing margin of the recording medium, such damage can be prevented. Further, a lock mechanism for preventing the pinch roller 26 from being raised carelessly is unnecessary, and the cost can be reduced accordingly. Furthermore, even when the carriage 20 is located above the pinch roller 26, the operability of the plotter 10 is improved because the pinch roller 26 can be raised for jam clearance or the like.
[0026]
【The invention's effect】
As described above, in the image forming apparatus of the present invention, for example, when one of the pair of transport rollers is lifted away from the other transport roller for jam processing, the raised transport roller contacts the carriage. Also, the carriage moves in a relaxing direction to reduce the impact due to this contact. For this reason, even if the transport roller is arranged near the carriage, neither the transport roller nor the carriage is damaged. Further, since a lock mechanism for locking the transport roller for preventing such damage is not required, the cost can be reduced accordingly.
[0027]
Here, a lower guide rail is fitted in the lower portion of the carriage and fixed to the image forming apparatus main body and extends in the main scanning direction. The carriage is guided by the lower guide rail to scan in the main scanning direction. In the case where the carriage moves in the relaxation direction by rotating about the lower guide rail, the carriage can be rotated with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a schematic configuration of an inkjet type plotter.
FIG. 2 is a side view showing a part of the carriage in a state where printing is possible;
FIG. 3 is a side view in which a part of a carriage slightly rotated about a lower guide rail as a rotation center is cut away.
[Explanation of symbols]
17 Lower guide rail 20 Carriage 22 Print head 24 Drive roller 26 Pinch roller

Claims (2)

A carriage that carries a print head for ejecting ink and scans in a predetermined main scanning direction; and a pair of conveyance rollers that convey the recording medium downward while nipping the recording medium. An image forming apparatus that forms an image by discharging ink onto a recording medium from a print head while scanning the carriage in the main scanning direction while transporting the carriage below the carriage.
The pair of transport rollers,
It is arranged below the carriage and comes into contact with and separates from each other,
The carriage,
A transport roller closer to the carriage of the pair of transport rollers moves away from the other transport roller and comes into contact with the carriage, so that the transport roller moves in a relaxation direction to reduce an impact due to the contact. Characteristic image forming apparatus. A lower guide rail into which the lower portion of the carriage is fitted and fixed to the image forming apparatus main body and extends in the main scanning direction;
The carriage,
It is guided by the lower guide rail and scans in the main scanning direction, and moves in the relaxation direction by rotating about the lower guide rail as a rotation center. The image forming apparatus according to claim 1.

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