JP2001301239A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color ink-jet printer capable of forming a high quality image, and capable of achieving cost reduction and a compact configuration. SOLUTION: This device comprises a conveyance path 3 for conveying a postcard P downward in the substantially vertical direction, a first conveyance means 2 for sending out to the conveyance path the postcard aligned and in a state with the top positioned, a second conveyance means 4 disposed on the downstream side in the conveyance direction with respect to the first conveyance means, for conveying and holding the postcard, and a pair of ink heads 5, 5 disposed facing the front and back surfaces of the postcard in the substantially horizontal direction on the downstream side in the conveyance direction with respect to the second conveyance means, for ejecting an ink to the front and back surfaces of the postcard in the substantially horizontal direction based on inputted image information. The second conveyance means 4 comprises a conveyance belt 41 for sliding against one side in the width direction of the postcard, and a slit 42 for positioning the other end in the width direction of the postcard.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as an ink jet printer, and more particularly to an apparatus for forming an image on both sides of a recording medium.

[0002]

2. Description of the Related Art In general, in an ink jet printer, an image is formed by ejecting ink to the surface of a recording medium based on image information input from an information processing device such as a personal computer. . As described above, an inkjet printer generally forms an image on one side in consumer use, and when forming an image on both sides, it is necessary to turn the recording medium having an image formed on one side upside down and form an image again. is there.

[0003] Most of the uses of ink jet printers at home include the creation of postcards such as New Year's cards and summer greetings. In this case, even when creating a postcard, it is necessary to turn the recording medium on which the image is formed on one side upside down to form an image of the body, so that not only the efficiency of image formation is reduced, but also when the book is turned upside down, it is turned upside down. May cause a bad postcard.

Therefore, conventionally, as an ink jet printer capable of forming an image on both the front and back surfaces of a recording medium, for example, as shown in FIG. A pair of upper and lower delivery rollers b, b for arranging and cueing the recording medium p with respect to a transport path a for transporting the paper in the direction, and a downstream side in the transport direction with respect to the respective feed rollers b (left side in FIG. 17).
And a pair of upper and lower paper feed rollers c, c for transporting and holding the recording medium p, and a pair of upper and lower paper rollers provided downstream of the respective paper feed rollers c in the transport direction for transporting and holding the recording medium p. Paper discharge rollers d are provided between the paper supply roller c and the paper discharge roller d so as to be substantially vertically opposed to the front and back surfaces of the recording medium p. A pair of upper and lower ink heads e and e for ejecting ink from a direction, and a recording medium p stretched between a paper feed roller c and a paper discharge roller d. An image is simultaneously formed by the ink heads e and e.

[0005]

However, in the conventional image forming apparatus such as an ink jet printer, the recording medium p is conveyed in a substantially horizontal direction, so that the following problems occur.

That is, the ink heads e and e need to be upward and downward, and the nozzles are stained by the drop of ink ejected from the upward ink head e, so that a high-quality image cannot be formed.

In order to keep the recording medium p conveyed in the horizontal direction at the same distance from the upper and lower ink heads e, e, the paper feed roller c and the paper discharge roller d which stretch the recording medium p are indispensable. And the cost increases.

Further, the recording medium p conveyed in the horizontal direction
Is large in plan view, and it is necessary to secure a discharge space for discharging the recording medium p, and the installation space of the image forming apparatus becomes very large.

SUMMARY OF THE INVENTION 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 forming a high-quality image and capable of reducing cost and size. Is to provide.

[0010]

According to the present invention, there is provided an image forming apparatus which forms an image by ejecting ink to a recording medium based on input image information. A transport path for transporting the medium substantially vertically downward, a first transport means for aligning and cueing the recording medium with respect to the transport path and sending the medium, and a transport path provided downstream of the first transport means in the transport direction. A second conveying means for conveying and holding the recording medium; and a second conveying means provided downstream of the second conveying means so as to substantially horizontally oppose both front and back surfaces of the recording medium. A pair of ink heads for discharging ink from a substantially horizontal direction with respect to the back surface.

According to this specific matter, the pair of ink heads ejects ink from a substantially horizontal direction on both the front and back surfaces of the recording medium conveyed in the conveyance path to form an image, so that the ink head ejects ink upward. As described above, the nozzle is not stained by the drop of ink, and a high-quality image can be formed on both the front and back surfaces of the recording medium. Further, the recording medium held by the second conveying means hangs in the vertical direction due to its own weight, and is kept at the same distance from the ink head in the substantially horizontal direction, so that the recording medium is downstream from each ink head in the conveying direction. No transporting means such as a transporting roller for holding the recording medium on the side becomes unnecessary, and the cost can be reduced. Further, the conveyance space (conveyance path) of the recording medium conveyed in a substantially vertical direction is very small in plan view, and the discharge space for discharging the recording medium can be provided below. The installation space is very small.

[0012] In particular, the following arrangements are provided to specify the first and second transport means.

That is, the first conveying means is a conveying roller which is in sliding contact with the recording medium, and the second conveying means is a conveying roller which is in sliding contact with one side in the width direction of the recording medium. And a slit for positioning the side. In this case, the recording medium in the conveyance path is conveyed by only the conveyance roller on one side in the width direction of the recording medium in combination with its own weight, and the cost of the conveyance unit can be reduced. Become.

[0014] On the other hand, the first conveying means is a conveying roller which is in sliding contact with the recording medium, and the second conveying means is a conveying belt which is in sliding contact with one side in the width direction of the recording medium in the conveying direction. In the case where the slit is configured to position the other side in the width direction of the recording medium, the distance for holding the recording medium is secured long in the transport direction, and it is possible to effectively prevent the bending of the recording medium in the transport direction. Becomes Further, since the recording medium is effectively held by the transport belt that is in long sliding contact with the recording medium in the transport direction, a roller (a roller that supports the belt) smaller in diameter than when a roller is used as the second transport unit. Can be used. For this reason, the interval between the second transport unit and each ink head in the recording medium transport direction can be reduced, and the non-printable area at the end of the recording medium can be reduced.

In addition to the above-mentioned specific items, both ends in the width direction of a recording medium on which an image is formed by ink ejected from each ink head are guided downstream of the pair of ink heads to the downstream end of the conveyance path. When the slit is provided, even if the recording medium that hangs down due to its own weight is warped or twisted, the warp or twist of the recording medium is corrected by the slit on the downstream side in the transport direction from the ink head, and the height of the ink head is reduced. It is possible to form a quality image smoothly. In addition, there is no need for a discharge roller for discharging the recording medium to the downstream side of the transport path, and the cost can be reduced.

In particular, the following configuration is provided to specify the scanning direction of a pair of ink heads.

That is, the ink head on the front side of the recording medium and the ink head on the back side of the recording medium are scanned in opposite directions during image formation. in this case,
The inertial forces of the ink heads at the time of scanning cancel each other out, and it is possible to suppress the vibration generated by the acceleration / deceleration of the ink heads.

In particular, the following configuration is specified to specify the layout of the maintenance station of the ink head.

That is, when a single maintenance station for maintaining each ink head is provided between each ink head on one side of the ink head in the main scanning direction, the image forming apparatus can be made compact in the ink head main scanning direction. Can be achieved.

In particular, the following configuration is specified to specify a driving source for scanning the ink head in the main scanning direction.

That is, when the pair of ink heads are connected to individual motors so as to be scanned by the driving force of the motors, when the ink heads are maintained, the respective ink heads are respectively moved by the individual motors in the main scanning direction. The ink head can be moved to the maintenance station on one side, and the maintenance of each ink head can be performed smoothly.

On the other hand, one of the pair of ink heads is connected to a single motor so as to scan by the driving force of the motor, and the other is driven by the driving force of the motor so as to scan by the driving force of the motor. When connected to the single motor through the driving force connecting / disconnecting means that can connect / disconnect, when performing maintenance of the ink head, one of the ink heads is moved to the maintenance station on one side in the main scanning direction. The driving force connecting and disconnecting means
First, after moving the other ink head to the maintenance station, the connection with the motor is cut off by the driving force connecting / disconnecting means, and one ink head is moved to the maintenance station by the driving force of the motor. As a result, maintenance of each ink head can be smoothly performed by a single motor, and the cost can be reduced by a single motor.

In particular, the following configuration is provided for specifying the movement of the ink head in the maintenance station.

That is, the pair of ink heads are supported on guide shafts extending in the main scanning direction, and when the maintenance of each ink head is performed at the maintenance station, the distance between the ink heads is changed so as to change the distance between the ink heads. When each guide shaft is movably supported, the ink jet processing (purge processing) from the nozzles can be performed at the maintenance station without changing the interval between the ink heads, and the head surface of each ink head is also Wiping process (wiping process),
When performing a process of sucking ink from the nozzles of each ink head (priming process) and a process of preventing the head surface of each ink head from drying (capping process), the intervals between the ink heads can be reduced. Contact the maintenance station from both the front and back sides. This makes it possible to smoothly perform a purging process, a wiping process, a priming process, a capping process, and the like at the maintenance station.

In particular, the following configuration is specified to specify an ink head.

In other words, when one of the pair of ink heads is to discharge color ink and the other is to discharge only black ink, when a postcard is applied as a recording medium, While printing the destination with black ink (image formation), the body of the body with color ink is vividly formed on the back side, and the other ink head is dedicated to inexpensive black ink. It is possible to provide an inexpensive image forming apparatus suitable for creating a postcard occupying the same.

[0027] One of the pair of ink heads is removably mounted so as to be replaceable with an image information reading device for reading image information, and the front and back surfaces of a recording medium facing the image information reading device. When an image information document to be read by the image information reading device is detachably attached to one of the ink heads, image information from the image information document read by the image information reading device replaced with one of the ink heads is replaced with the other. Is input to the other ink head, the other ink head forms the same image as the image information document on one of the front and back surfaces of the recording medium (the opposite side of the image information document). This makes it possible to use an image forming apparatus capable of forming an image on both sides of a recording medium as a copying machine. In addition, a memory function of a storage device that forms an image with the other ink head for each image information of the image information document read by the image information reading device and stores the image information of the image information document read by the image information reading device is provided. It is possible to configure a simple and inexpensive storage device by minimizing it.

In particular, the following configuration is listed as one for facilitating the conveyance of the recording medium on the conveyance path.

That is, when the slit of the second conveying means is provided so as to be movable in the width direction in accordance with the width of the recording medium sent to the conveying path, the recording paper can be smoothly moved regardless of its size. And the image formation by each ink head can be performed smoothly.

Further, the following configuration is provided to specify the discharge location of the recording medium discharged from the transport path.

That is, the image forming apparatus main body is provided with a retractable leg portion that extends downward, and the leg portion is extended during image formation, thereby discharging the recording medium discharged below the downstream end of the transport path. When the portion is formed at the lower portion of the image forming apparatus main body, the image forming apparatus can be housed compactly by immersing the legs when the image forming apparatus is not used. On the other hand, when the image forming apparatus is used, the paper ejecting section appears at the lower portion of the image forming apparatus main body by extending the leg section, and the recording medium that naturally falls due to its own weight is smoothly transferred to the paper ejecting section without being rubbed on the front and back surfaces thereof. It becomes possible to discharge.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a storage state without using a color inkjet printer as an image forming apparatus, and FIG. 2 shows a usage state using a color inkjet printer.

As shown in FIGS. 1 and 2, the color ink jet printer 1 has a paper feed tray 12 on the upper side of a substantially rectangular printer main body 11 as an image forming apparatus main body.
A paper feed slot 13 (shown in FIG. 2) is provided so as to be detachably attached thereto, and the paper feed tray 12 is mounted to the paper feed slot 13 in an upright state from obliquely above. On this paper feed tray 12, the paper feed position of the postcard P as a recording medium placed thereon is positioned from one side in the width direction (back side in FIG. 2) from the other side (front side in FIG. 2). Are provided. The positioning member 12 is provided with a sheet feeding tray 12.
It is supported so as to be movable in the width direction according to the width of the paper placed thereon. In addition, the printer body 11 includes a substantially rectangular frame-shaped leg portion 14 slidably supported in the vertical direction with respect to the outer surface thereof. The leg portion 14 is stored in a state of being superimposed along the outer surface of the printer main body 11 when storing the color inkjet printer 1 (the state shown in FIG. 1), while the leg portion 14 is attached to the outer surface of the printer main body 11 when the color inkjet printer 1 is used. It is pulled out downward along, and only the upper part is used in a state of being overlapped (the state shown in FIG. 2). When the color inkjet printer 1 is used, the leg 14 is pulled out downward, so that the printer main body 1 is located below the printer main body 11 (inside the leg 14).
A paper discharge unit 15 that receives the postcard P discharged from the printer 1 is configured. In this case, the color inkjet printer 1 can be housed compactly by immersing the legs 14 when the color inkjet printer 1 is not used, while the legs 14 are advanced downward when the color inkjet printer 1 is used. The paper discharge unit 14 appears at the lower part of the printer main body 11, and the postcard P, which naturally falls due to its own weight, can be smoothly discharged to the paper discharge unit 14 without the front and back surfaces being rubbed.

On the other hand, as shown in FIGS. 3 and 4, a paper feed tray 12 (paper
3), the pickup roller 16
(Shown in FIG. 3), a first conveying means 2, a substantially I-shaped conveying path 3 extending in the vertical direction, a second conveying means 4, a pair of ink heads 5, 5 (shown in FIG. 3) and a third Transport means 6 are provided in order.

The pickup roller 16 is provided on the sheet feeding tray 1.
2 is used to take out one of the postcards P placed on the second transport means 2 and transfer it to the first transport means 2.

The first transport means 2 comprises a pair of paper feed rollers 21 and 21 as transport rollers which slide on the postcard P from both front and back sides. Each of the paper feed rollers 21 is formed longer than both ends in the width direction orthogonal to the transport direction of the postcard P (the direction of arrow A shown in FIGS. 3 and 4). And
Each paper feed roller 21 (first transport means 2) aligns and cues out the postcard P delivered and received by the pickup roller 16, and sends the postcard P to the transport path 3.

The transport path 3 is for transporting the postcard P caught by each of the paper feed rollers 21 of the first transport means 2 toward the paper discharge section 14 vertically downward.

The second transporting means 4 is provided downstream of the first transporting means 2 in the transporting direction and transports and holds the postcard P. One side of the postcard P in the width direction is provided on both front and back sides. A pair of transport belts 41, 41 sliding from the side, and a slit 42 for positioning the other side in the width direction of the postcard P are provided. As shown in FIG. 3, each conveyor belt 41 has upper and lower roller members 41 a, 41 a arranged at predetermined intervals in the conveyance direction on one side in the width direction of the postcard P, and between the upper and lower roller members 41 a, 41 a. Belt 41
b, so that one side in the width direction of the postcard P is slid in the transport direction from both sides of the front and back sides. On the other hand, as shown in FIG. 5, the slit 42 includes opposing pieces 42a, 42a for positioning the other side in the width direction of the postcard P from both sides.
The opposite ends 42a, 42a of the opposite postcard P side are connected,
And a positioning piece 42b for positioning by contacting the other end in the width direction of the postcard P. The upper part of each opposing piece 42a is inclined so as to be separated from each other as it goes upward, and the postcard P sent to the transport path 3 by the first transport means 2 is used.
The other side in the width direction is formed in a shape that can be easily inserted between the opposing pieces 42a, 42a.

As shown in FIGS. 3 and 4, the pair of ink heads 5 and 5 are substantially horizontally opposed to the front and back surfaces of the postcard P on the downstream side of the second conveying means 4 in the conveying direction. It is configured to eject ink from a substantially horizontal direction to the front and back surfaces of the postcard P based on image information input from a personal computer (not shown) or the like. Each of the ink heads 5 has an ink tank (not shown), and is mounted on the ink carriages 51 and 52 on both sides of the postcard P together with the ink tank. As shown in FIG. 6, the front and rear ink carriages 51 and 52 are connected to a drive mechanism 50. The drive mechanism 50 includes a drive motor 50a capable of rotating forward and reverse.
A first pulley 50c rotatably connected to a drive shaft 50b of the drive motor 50a, a second pulley 50d rotatably connected to a shaft 50f of a back side drive pulley 50g described later, and a first pulley 50c. A power transmission belt 50e stretched between the second pulley 50d and the other side in the width direction on the back side of the postcard P (the left side in FIG. 6), and the driving force of the driving motor 50a is applied to the first pulley 50b and the second pulley 50d. The second drive pulley 50g transmitted from the second pulley 50c via the shaft 50f and one side in the width direction on the back side of the postcard P (FIG. 6).
(The right side), a back driven pulley 50h provided on the right side), a back belt 50i stretched between the back driven pulley 50g and the back driven pulley 50h, and a front drive provided on the other side in the width direction on the front side of the postcard P. Pulley 50j and postcard P
, A front driven pulley 50k, a front driven pulley 50j, and a front driven pulley 50
k and the front side belt 50l that is stretched between k and the drive shaft 50b of the drive motor 50a.
An electromagnetic clutch 50m is provided as driving force connecting / disconnecting means for connecting / disconnecting the driving force of the drive motor 50a to / from the front drive pulley 50j. 50g of the back side drive pulley
Belt 50 between the rear driven pulley 50h and the rear driven pulley 50h
The forward path i (upper side in FIG. 6) is the back side ink carriage 52
On the other hand, the forward path (lower side in FIG. 6) of the front belt 50l between the front drive pulley 50j and the front driven pulley 50k is fixed to the front ink carriage 51. The front-side ink carriage 51 (ink head 5) and the back-side ink carriage 52 (ink head 5) each have a guide shaft 50n as a guide shaft extending in the main scanning direction on both front and back sides of the postcard P.
The guide shaft 5 is supported in the vertical direction (main scanning direction) in FIG.
Reciprocable along 0n. In this case, the front-side ink carriage 51 (front-side ink head 5) and the back-side ink carriage 52 (back-side ink head 5) scan in opposite directions during image formation.

The ink tank mounted on the front side ink carriage 51 is a single ink tank containing Bk (black) ink. On the other hand, the back side ink carriage 5
The ink tanks mounted on Y2 are Y (yellow), M
There are four inks each containing (magenta), C (cyan), and Bk (black) inks, which are sequentially arranged in the main scanning direction. Further, inside each ink head 5, a plurality of nozzles (not shown) which are individually connected to the ink tank via a supply path (not shown) are provided.

The third transport means 6 is provided downstream of each ink head 5 in the transport direction, and transports both ends in the width direction of the postcard P on which an image is formed by ink ejected from each ink head 5 to the transport path 3. Are provided at the downstream end. Each of the slits 61 is shown in FIG.
As shown in the figure, opposing pieces 61a, 61a for positioning one side or the other side in the width direction of the postcard P from the front and back sides, and the opposite end of the opposing pieces 61a, 61a on the opposite side of the postcard P, are connected to each other, A positioning piece 61b for positioning by contacting one end or the other end. The upper portion of each opposing piece 61a is inclined so as to be separated from each other as it goes upward, so that one side or the other side in the width direction of the image-formed postcard P is formed in a shape that can be easily inserted between the opposing pieces 61a, 61a. Have been. In this case, the slit 61 on the other side in the width direction of the postcard P is
Along with the slit 42 of the second transport means 4, the postcard P is moved in the width direction along with the movement of the positioning member 12a in the width direction. Accordingly, the recording paper such as the postcard P can be smoothly transported regardless of the size of the recording paper, and the image formation by the ink heads 5 can be smoothly performed.

The color ink jet printer 1 has a control device (not shown) for controlling each part. The processes and operations in the color inkjet printer 1 described below are controlled by the control device unless otherwise specified.

When the printing operation of the color ink jet printer 1 is started, first, one of the postcards P placed on the paper feed tray 12 is taken out by the pickup roller 16, and the paper feed roller 21 (first Transportation means 2)
Are sent to the transport path 3 in a state where they are aligned and located at the same position. The postcard P sent out to the transport path 3 is transported by a pair of transport belts 41, 41 sliding on one side in the width direction from both front and back sides while the other side in the width direction is positioned by the slit 42. 3 is conveyed while being held on the downstream side (vertically downward). Thereafter, when the front and back surfaces of the postcard P are conveyed to a position facing the respective ink heads 5, the postcard P is transferred to the respective ink heads 5.
When the ink passes through a position opposing to the postcard P, ink of different colors is individually ejected in a droplet form from each nozzle provided in each ink head 5 based on the position of the postcard P and print data. Image formation is performed on both the front and back surfaces of.

The image forming operation will be specifically described.
When the postcard P is conveyed to a position facing each ink head 5, the front and back ink carriages 51 and 52 move in the direction of arrow B (main scanning direction) in FIG. Ink is ejected toward both sides, and an image is formed on the postcard P by this. When each of the ink carriages 51 and 52 moves to one end or the other end in the width direction of the postcard P, the postcard P is moved (conveyed) downward by a predetermined amount (indicated by an arrow A in FIGS. 3 and 4). (After moving in the sub-scanning direction shown)).
Then, image formation is performed while the ink carriages 51 and 52 move in the direction of arrow B (main scanning direction) in FIGS. Thus, each ink carriage 5
An image forming operation by moving 1,52 in the main scanning direction;
The image forming is performed on the entire front and back surfaces of the postcard P by alternately performing the feeding operation of the postcard P.

The postcard P on which an image is formed in substantially the entire area on both the front and back sides is guided by the slits 61 of the third conveying means 6 and discharged toward the paper discharge section 15.

As shown in FIGS. 7 to 10, a single maintenance for maintaining each ink head 5 is provided on one side of the ink carriages 51 and 52 in the main scanning direction (one side in the width direction of the postcard P). A station 7 is provided. As shown in FIGS. 7 and 8, the maintenance station 7 includes a purge processing unit 71 that performs a purge process for discharging ink from the nozzles of each ink head 5 and a wiping process that performs a wiping process for wiping the head surface of each ink head 5. A processing unit (not shown) and, as shown in FIGS. 9 and 10, capping for performing a prime process for sucking ink from the nozzles of each ink head 5 and a capping process for preventing the head surface of each ink head 5 from drying. A purging unit 71, a wiping unit, or a capping / priming unit 72, by a conversion mechanism (not shown), in accordance with a maintenance request for each ink head 5; 52 each ink head 5 on one side in the main scanning direction
It is converted to be positioned between.

As shown in FIGS. 7 and 8, the purge processing section 71 is formed in a frame shape surrounding the periphery of a plate-like urethane sponge 71a arranged so that the front and back faces each ink head 5 from the outside. A hose 71b (shown in FIG. 8), which is formed and guides ink discharged to the front and back surfaces of the urethane sponge 71a from the lower end to a waste liquid tank (not shown), is provided. As shown in FIG. 9 and FIG. 10, the capping / priming processing section 72
And relief portions 72a, 72a for preventing interference with the nozzles of the respective ink heads are respectively provided at the center portions of the front and back surfaces. This capping
The prime processing section 72 is made of silicone rubber, and has a suction hose 72b (shown in FIG. 10) that holds the inside of each escape section 72a in a vacuum state with the head surface of each ink head 5 capped on the front and back surfaces. Have.

As shown in FIGS. 11 and 12, the guide shaft 50n of each of the ink carriages 51 and 52 (each of the ink heads 5) changes the distance between the ink heads 5 and 5 in the maintenance station 7. Is provided. The movable mechanism 73 includes a cam gear 73b that meshes with a drive gear 73a that is rotated by a stepping motor that can be rotated forward and backward (not shown). The cam gear 73b is rotatably supported by a rotating shaft 73c extending between the guide shafts 50n and 50n in the main scanning direction, and has a substantially quarter-arc eccentric groove 73d, which is point-symmetric with respect to the rotating shaft 73c. 73
d is the guide shaft 5 of each ink carriage 51, 52.
0n are slidably inserted respectively. Each guide shaft 50n has a long hole 7 extending in the front and back directions of the postcard P.
4, 74, respectively, are slidably supported. When the maintenance station 7 performs maintenance on each of the ink heads 5, the guide shaft 50 n rotates the cam gear 73 b through the drive gear 73 a by approximately one-quarter rotation to reduce the interval between the ink heads 5. The postcard P is movably supported in the front and back directions so as to be changed.

More specifically, when the maintenance of each ink head 5 is performed, when the front side ink carriage 51 is moved to the maintenance station 7 on one side in the main scanning direction, the front side drive pulley 5 is moved by the electromagnetic clutch 50m.
0j is connected to the drive motor 50a, the front side ink carriage 51 is moved to the maintenance station 7 by the driving force of the drive motor 50a, and then the front side drive pulley 50j and the drive motor 50a are disconnected by the electromagnetic clutch 50m. The back side ink carriage 52 is moved to the maintenance station 7 by the driving force of the driving motor 50a. When the ink carriages 51 and 52 are moved to the maintenance station 7,
Each guide shaft 50n, 50n is located at one end of the eccentric groove 73d, and each ink head 5 is in the most distant state (FIG. 11).
), The drive gear 73 is moved after the ink carriages 51 and 52 are positioned at the maintenance station 7.
a in the direction of the arrow shown in FIG.
Is rotated in the direction of the arrow shown in FIG. Then, each guide shaft 50n slides inside the long hole 74 while being guided inside the eccentric groove 73d to the other end, and each guide shaft 50n, 50n is positioned at the other end of the eccentric groove 73d. The state in which the ink head 5 is closest is shown (the state shown in FIG. 12). At this time, as shown in FIG. 7, when the maintenance station 7 has been converted to the purge processing unit 71, each ink head 5 is positioned at a position where the ink head 5 can easily be ejected to the front and back surfaces of the urethane sponge 71a. Also,
As shown in FIG. 9, when the maintenance station 7 has been converted to the capping / prime processing section 72, the periphery of each ink head 5 is positioned at the capping position where it contacts the front and back surfaces of the capping / prime processing section 72.

On the other hand, when an image is formed by each ink head 5, each guide shaft 50n, 50n is
The driving gear 73a is moved from the state where each ink head 5 is located closest to the other end of 3d (the state shown in FIG. 12) to the position shown in FIG.
And the cam gear 73b is rotated in the direction of the arrow shown in FIG. Then, each guide shaft 50n slides outward in the elongated hole 74 while being guided in the eccentric groove 73d to one end side, and each guide shaft 50n, 5
0n is located at one end of the eccentric groove 73d, so that each ink head 5 is in the most distant state (the state shown in FIG. 11),
In this state, the ink carriages 51 and 52 are moved from the maintenance station 7 to the image forming position.
Each of the guide shafts 50n, 50n is positioned by the cam gear 73b in a state suitable for image formation.

In the case of this embodiment, the pair of ink heads 5 and 5 eject ink from substantially horizontal directions on both the front and back surfaces of the postcard P conveyed along the conveyance path 3 to form an image. No nozzle is stained by ink drop like ink head which discharges
High quality images can be formed on both the front and back sides of the postcard P.

Each transport belt 4 of the second transport means 4
The postcard P held from one side in the width direction of the postcard P by both sides from the front and back sides by 1 hangs down in the vertical direction by its own weight, and is kept at the same distance from the ink head 5 in the substantially horizontal direction. Therefore, it is not necessary to provide a holding means such as a conveyance belt or a conveyance roller on the other side in the width direction of the postcard P, and it is also necessary to hold the postcard P by a discharge roller downstream of each ink head 5 in the conveyance direction. Cost can be reduced. Moreover, the distance for holding the postcard P is ensured by the conveyance belt 41 in the conveyance direction to be long, and the postcard P can be effectively held, so that bending of the postcard P in the conveyance direction can be effectively prevented. The distance in the transport direction between the transport belt 41 and each of the ink heads 5 can be reduced, and the non-printable area at the end of the postcard P can be reduced.

In addition, the transport space (transport path 3) of the postcard P conveyed in a substantially vertical direction becomes very small in plan view, and the paper discharge unit 15 (discharge space) for discharging the postcard P is lowered. This makes it possible to provide a very small installation space for the color inkjet printer 1. In addition, both ends in the width direction of the postcard P are located on the downstream side of the pair of ink heads 5 in the transport direction.
Is guided to the downstream end of the transport path 3 by the slits 61 of the transporting means 6, so that even if the postcard P hanging down by its own weight is warped or twisted, the warp or twist of the postcard P is corrected by the slits 61. As a result, a high-quality image can be smoothly formed by the ink head 5. Further, since four types of ink tanks are mounted on the back side ink carriage 52, while a single black ink tank is mounted on the front side ink carriage 51, the destination of the postcard P with black ink is printed. (Image formation) On the other hand, the main body using four kinds of inks can be vividly formed on the back side of the ink, and the ink head 5 of the front side ink carriage 51 is dedicated to inexpensive black ink, so that most of the uses at home can be performed. The color ink jet printer 1 suitable for producing a postcard P occupying the cost can be provided at low cost.

In addition, since the maintenance station 7 for each ink head 5 is provided on one side of the ink carriages 51 and 52 in the main scanning direction, the color inkjet printer 1 can be made compact in the ink carriage main scanning direction. Can be. Further, since the front side ink carriage 51 and the back side ink carriage 52 scan in opposite directions at the time of image formation, the inertial forces of the respective ink heads 5 at the time of the search are canceled each other, and the ink heads 5 are scanned.
Vibration caused by acceleration / deceleration of the vehicle can be suppressed.

Further, each of the ink carriages 51 and 52 is scanned by the driving mechanism 50 having the electromagnetic clutch 50m for connecting and disconnecting the driving force of the single driving motor 50a.
The ink carriages 51 and 52 that scan in opposite directions can be moved to the maintenance station 7, the maintenance of each ink head 5 can be facilitated by the single drive motor 50a, and the cost can be reduced by the single drive motor 50a. Can be achieved. Further, when performing maintenance on each of the ink heads 5 at the maintenance station 7, the cam gear 73b is rotated by approximately one quarter through the drive gear 73a of the movable mechanism 73, thereby changing the interval between the ink heads 5 with each other. As the guide shafts 50n move in the front and back directions of the postcard P,
Purge processing in the purge processing section 71 of the maintenance station 7, wiping processing in the wiping processing section, and priming and capping processing in the capping / priming processing section 72 can be smoothly performed.

In this embodiment, an image is formed on the front and back surfaces of the postcard P based on image information input from a personal computer or the like. However, as shown in FIG. The head 5 and the ink tank are removably mounted on the front-side ink carriage 51.
With the ink tank removed, an image information reading scanner 81 as an image information reading device for reading image information on the front side of the postcard P is detachably mounted, and the ink head 5 and the ink tank are exchanged with the image reading scanner 81. It can be so. As shown in FIG. 14, a transparent sheet holder 82 for detachably attaching an image information document PC read by the image information reading scanner 81 is provided on the surface of the postcard P facing the image information reading scanner 81. Seat holder 82
The image information reading scanner 81 may read the image information on the front side of the image information document PC held on the front side of the postcard P with the lower ends of the image information documents PC having the same dimensions as the postcard P aligned. In this case, the image information on the front side of the image information document PC read by the image information reading scanner 81 is stored in a storage device (not shown), and is stored in the front side ink carriage 51 (image information reading scanner 8).
Every time 1) moves to one end or the other end in the width direction of the postcard P, the image information is written on the back side of the postcard P by the ink head 5 of the back side ink carriage 52 based on the image information written in the storage device. The same image as the image on the front side of the document PC is formed. Thus, the color inkjet printer 1 capable of forming images on both sides of the postcard P can be used as a copying machine. In addition, an image is formed by the ink head 5 of the back side ink carriage 52 for each image information of the image information document PC read by the image information reading scanner 81, and the image information of the image information document PC read by the image information reading scanner 81 is formed. It is possible to configure a simple and inexpensive storage device by minimizing the memory function of the storage device for storing the data.

In the present embodiment, each of the ink carriages 51 and 52 is scanned by a single drive motor 50a. However, as shown in FIG. 15, a front drive motor 91a provided on the front side of the postcard P is used. A front drive pulley 91c provided on the other side in the width direction on the front side of the postcard P (the left side in FIG. 15) and connected to the drive shaft 91b of the front drive motor 91a so as to rotate integrally therewith. Driven pulley 9 provided on the side (right side in FIG. 15)
1d, front drive pulley 91c and front driven pulley 91d
, A back-side drive motor 91f provided on the back side of the postcard P, and a back-side drive motor 91f provided on one side in the width direction on the back side of the postcard P.
A back drive pulley 91h rotatably connected to the drive shaft 91g of the above, a back driven pulley 91i provided on the other side in the width direction on the back side of the postcard P, and a back drive pulley 91h and a back driven pulley 91i. Backside belt 9 passed
1j may constitute the drive mechanism 91. In this case, when the maintenance of the ink heads 5 is performed, each of the ink carriages 51 and 52 can be moved to the maintenance station 7 on one side in the main scanning direction by the individual drive motors 91a and 91f. Maintenance can be performed smoothly.

On the other hand, as shown in FIG. 16, a drive motor 92a provided on the front side of the postcard P and a drive motor 92a provided on one side in the width direction on the front side of the postcard P (right side in FIG. 16). A drive pulley 92c rotatably connected to the post 92P and the other side in the width direction on the front side of the postcard P (FIG. 1).
6, a left side driven pulley 92d provided on the other side in the width direction on the back side of the postcard P, and a back side driven pulley 92e provided on the other side in the width direction on the back side of the postcard P. 2 driven pulleys 92f and each pulley 92
The drive mechanism 92 may be configured by the belt 92g that is sequentially stretched over c to 92f. in this case,
Although not shown, the maintenance station is dedicated to the front side and the back side, and is separately provided on one side and the other side in the width direction.

Further, in the present embodiment, the second conveying means 4 is constituted by the conveying belt 41 and the slit 42. However, the second conveying means comprises a conveying roller on one side in the width direction of the postcard and another side in the width direction. And may be constituted by slits.

The third transfer means 6 may not be provided.

Further, in this embodiment, the postcard P is applied as a recording medium, but the present invention is not limited to this, and any other paper (recording medium) may be applied.

[0063]

As described above, according to the present invention, an image is formed by ejecting ink from a pair of ink heads in a substantially horizontal direction on both the front and back surfaces of a recording medium conveyed substantially vertically downward in a conveyance path. Thus, a high-quality image can be formed on both the front and back surfaces of the recording medium without soiling the nozzles. Further, the recording medium held by the second conveying means is vertically suspended by its own weight and kept at the same distance from the ink heads, so that the holding by the conveying rollers and the like on the downstream side in the conveying direction from each ink head can be performed. This is unnecessary, and the cost can be reduced. Further, the space for conveying the recording medium can be made very small in plan view, and the space for discharging the recording medium can be provided below, so that the space for installing the image forming apparatus can be made very small.

In addition, by providing slits for guiding both ends in the width direction of the recording medium downstream of the ink head in the conveyance direction, the warpage and twist of the recording medium are corrected, and a high-quality image formed by the ink head is formed. It can be formed smoothly.

In particular, the second transport means is constituted by a transport roller on one side in the width direction of the recording medium and a slit on the other side in the width direction of the recording medium. The transport is performed only by one transport roller, and the cost of the transport unit can be reduced.

On the other hand, if the second transport means is constituted by the transport belt on one side in the width direction of the recording medium and the slit on the other side in the width direction of the recording medium, a long holding distance of the recording medium can be ensured in the transport direction. In addition to effectively preventing the recording medium from being bent, the distance between the transport belt and each ink head in the transport direction can be reduced, and the non-printable area at the end of the recording medium can be reduced. Can be.

In particular, by scanning the ink head on the front surface side and the ink head on the back surface of the recording medium in directions opposite to each other, the inertial forces of the ink heads can be canceled each other, and the vibration during acceleration / deceleration of the ink head is suppressed. be able to.

By providing a single maintenance station between each ink head on one side of the ink head in the main scanning direction, the image forming apparatus can be made compact in the ink head main scanning direction.

In this case, by connecting the pair of ink heads to individual motors, maintenance of each ink head can be performed smoothly.

On the other hand, by connecting one ink head to a single motor and connecting the other ink head to the single motor via a driving force connecting / disconnecting means, a single motor can be used. Maintenance of each ink head can be facilitated, and the cost can be reduced by a single motor.

In particular, purging, wiping, priming, and capping at the maintenance station are supported by movably supporting each guide shaft in the front and back directions of the recording medium so as to change the interval between the ink heads. Can be performed smoothly.

Further, by using one ink head for discharging color ink and the other for discharging black ink, an image forming apparatus suitable for producing postcards, which occupies most of home uses, is provided at low cost. be able to.

In addition, one of the ink heads is replaceable with the image information reading device, and the image information original is detachably mounted on the front or back surface of the recording medium facing the image information reading device, thereby enabling the image forming device to be mounted. Can be used as a copying machine, and a simple and inexpensive storage device can be configured by minimizing the memory function of the storage device.

In particular, by providing the slit of the second conveying means so as to be movable in the width direction according to the width dimension of the recording medium,
The recording paper can be smoothly transported regardless of its size, and the image formation by each ink head can be performed smoothly.

Further, a retractable leg portion is provided below the main body of the image forming apparatus, and when the image forming apparatus is used, the leg portion is advanced to form a paper discharge portion of the recording medium at a lower portion of the main body of the image forming apparatus. The recording medium that falls naturally under its own weight can be smoothly discharged to the discharge section. On the other hand, the image forming apparatus can be stored compactly by immersing the legs when the image forming apparatus is not used.

[Brief description of the drawings]

FIG. 1 is an external perspective view illustrating a non-use state of a color inkjet printer according to an embodiment of the present invention.

FIG. 2 is an external perspective view illustrating a use state of the color inkjet printer.

FIG. 3 is a sectional view showing the internal structure of the color inkjet printer.

FIG. 4 is a perspective view showing an internal structure of the color inkjet printer.

FIG. 5 is a perspective view of a slit.

FIG. 6 is an explanatory diagram schematically showing a configuration of a driving mechanism.

FIG. 7 is a plan view of the ink head showing a maintenance state in the purge processing unit.

FIG. 8 is a front view of the purge processing unit as viewed from the back side.

FIG. 9 is a plan view of the ink head showing a maintenance state in the capping / prime processing unit.

FIG. 10 is a front view of the capping / prime processing unit as viewed from the back side.

FIG. 11 is a side view of the movable mechanism showing a state where each ink head is farthest away.

FIG. 12 is a side view of the movable mechanism showing a state in which each ink head is closest to each other.

FIG. 13 is a side view of the vicinity of each ink carriage according to a modification of the present embodiment viewed from the other side in the width direction of the postcard.

FIG. 14 is an explanatory diagram for explaining a mounting state of the image information document to the sheet holder from the other side in the width direction of the postcard.

FIG. 15 is an explanatory view schematically showing a configuration of a drive mechanism according to another modification.

FIG. 16 is an explanatory diagram schematically showing a configuration of a drive mechanism according to another modification.

FIG. 17 is a cross-sectional view illustrating an internal structure of an image forming apparatus according to a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Color inkjet printer (image forming apparatus) 11 Printer main body (image forming apparatus main body) 14 Leg part 15 Paper discharge part 2 1st conveying means 21 Paper feed roller (conveying roller) 3 Conveying path 4 2nd conveying means 41 Conveying Belt 42 slit 5 ink head 50a drive motor (motor) 50m electromagnetic clutch (drive force connecting / disconnecting means) 50n guide shaft (guide shaft) 61 slit 7 maintenance station 81 image information reading scanner (image information reading device) P postcard (recording medium) ) PC image information manuscript

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B65H 5/38 B41J 3/00 S 3F102 9/14 3/04 101Z F-term (Reference) 2C055 KK00 KK02 KK05 KK12 KK13 2C056 EA18 EA23 EA24 HA29 HA30 HA38 HA58 JA05 JA10 JA17 2C062 RA03 RA06 3F049 DA02 DA12 LA07 LB05 3F101 FA01 FC18 FD02 LA07 LB05 3F102 AA11 AB02 BA02 BA09 BB02 DA08

Claims (13)

[Claims] 1. An image forming apparatus for forming an image by ejecting ink onto a recording medium based on input image information, comprising: a conveying path for conveying the recording medium substantially vertically downward; A first conveying means for aligning and cueing the recording medium and sending it out; and a first conveying means provided downstream of the first conveying means in the conveying direction.
A second transporting means for transporting and holding the recording medium; and a second transporting means provided downstream of the second transporting means in a transporting direction so as to be substantially horizontally opposed to the front and back surfaces of the recording medium. An image forming apparatus comprising: a pair of ink heads for ejecting ink from a substantially horizontal direction. 2. The image forming apparatus according to claim 1, wherein the first transport unit includes a transport roller that is in sliding contact with the recording medium, and the second transport unit is located on one side in the width direction of the recording medium. An image forming apparatus comprising: a conveying roller that comes into sliding contact with a recording medium; and a slit that positions the other side of the recording medium in the width direction. 3. The image forming apparatus according to claim 1, wherein the first transporting means comprises a transporting roller slidably contacting the recording medium, and wherein the second transporting means is provided on one side in the width direction of the recording medium. An image forming apparatus comprising: a conveyance belt that slides long in the conveyance direction; and a slit that positions the other side of the recording medium in the width direction. 4. The image forming apparatus according to claim 1, wherein both ends in the width direction of a recording medium on which an image is formed by ink ejected from each of the ink heads are located downstream of the pair of ink heads in the transport direction. An image forming apparatus, wherein a slit is provided at a downstream end of a conveyance path to guide the image. 5. The image forming apparatus according to claim 1, wherein the ink head on the front side of the recording medium and the ink head on the back side of the recording medium scan in opposite directions during image formation. An image forming apparatus comprising: 6. The image forming apparatus according to claim 5, wherein a single maintenance station for maintaining each ink head is provided between each ink head on one side in the main scanning direction of the ink head. An image forming apparatus comprising: 7. The image forming apparatus according to claim 6, wherein the pair of ink heads are connected to individual motors so as to be scanned by a driving force of the motor. . 8. The image forming apparatus according to claim 6, wherein one of the pair of ink heads is connected to a single motor so as to be scanned by a driving force of the motor, and the other is connected to a single motor. An image forming apparatus which is connected to the single motor via a driving force connecting / disconnecting means for connecting / disconnecting the driving force of the motor so as to be scanned by the driving force of the motor. 9. The image forming apparatus according to claim 6, wherein each of the pair of ink heads is supported by a guide shaft extending in the main scanning direction, and each of the guide shafts is used for maintenance of each ink head in a maintenance station. An image forming apparatus which is supported so as to be movable in the front and back directions of a recording medium so as to change the distance between the ink heads. 10. The image forming apparatus according to claim 1, wherein one of the pair of ink heads discharges color ink, and the other discharges only black ink. Characteristic image forming apparatus. 11. The image forming apparatus according to claim 1, wherein one of the pair of ink heads is detachably mounted and is replaceable with an image information reading device that reads image information. An image forming apparatus, wherein an image information document to be read by the image information reading device is detachably attached to one of the front and back surfaces of a recording medium facing the image information reading device. 12. The image forming apparatus according to claim 2, wherein the slit of the second conveying means is provided so as to be movable in the width direction according to the width of the recording medium sent to the conveying path. An image forming apparatus. 13. The image forming apparatus according to claim 1, wherein the main body of the image forming apparatus includes a leg that can move forward and backward, and the leg is advanced at the time of forming an image, so that the main body of the image forming device moves downstream of the transport path. An image forming apparatus, wherein a discharge portion of a recording medium discharged below an end is formed at a lower portion of the image forming apparatus main body.