JP2002356026A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arrangement for realizing total compaction, reliable imaging operation and good maintenance operation in an ink jet printer having a line head. SOLUTION: A belt mechanism 62 is disposed under a line head 61. A part of the outer surface of a belt 62b is a sheet carrying region A and another part thereof is a maintenance region B. A platen 63 is disposed in the belt mechanism 62. A maintenance unit 64 is disposed under the belt mechanism 62. At the time of imaging operation, the sheet carrying region A is opposed to the line head 61 and a negative pressure generated from the maintenance unit 64 is applied to the belt 62b through the platen 63. At the time of maintenance operation, a spitting process and a face wiping process are performed while opposing the maintenance region B to the line head 61 and waste ink is sucked by means of the maintenance unit 64.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink jet printer. In particular, the present invention relates to measures for improving the maintainability of a head in an ink jet printer having a line head.

[0002]

2. Description of the Related Art Conventionally, a serial head and a line head are generally known as ink heads used in an ink jet printer.

The above serial head is disclosed in, for example,
As disclosed in Japanese Patent Application Laid-Open No. 115195, it is supported so as to be able to reciprocate in a direction perpendicular to the sheet conveying direction.
The intermittent conveyance of the paper and the reciprocation of the head are performed alternately, and ink droplets are ejected from the ink nozzles toward the paper during the reciprocation of the head. Is formed. This type has the advantage that the size of the head can be reduced and the overall size of the ink jet printer can be reduced.

On the other hand, a line head is disclosed in, for example,
As disclosed in JP-A-291511, ink nozzles are arranged so as to face the entire sheet in the sheet width direction (the direction orthogonal to the sheet conveying direction). Then, the paper transport operation and the ink discharge operation from the ink nozzles are performed in parallel without moving the head, whereby an image composed of predetermined dots is formed on the paper surface. This type has a large number of ink nozzles, so the head itself becomes large.However, since it does not require reciprocating movement of the head, high-speed image formation can be performed as compared with the serial head. There is an advantage that it can be done. Another advantage is that the image resolution in the paper transport direction can be easily changed by adjusting the paper transport speed and the ink ejection timing.

In these ink heads, maintenance (an operation for preventing clogging of the ink nozzles) is performed at a predetermined time or a predetermined number of times of ink ejection. (A clogging prevention operation by ejecting the ink nozzles) and a face wiping process (a cleaning operation of the ink ejection openings by wiping the surface of the ink nozzles) must be performed. This maintenance operation is performed by a maintenance unit that can face the ink head.

In the case of the serial head, the maintenance unit is disposed at one end of the ink nozzle in the moving direction (hereinafter, referred to as a home position). Therefore, by moving the ink nozzle to the home position, the ink nozzle faces the maintenance unit, and a predetermined maintenance operation is performed. As described above, in the printer including the serial head, since the head itself is small, the maintenance unit can also be small, and its arrangement and design are easy.

On the other hand, in the case of a line head, since the head itself is large, it is impossible to dispose the maintenance unit at the above position. As an example of an arrangement form of the maintenance unit in the inkjet printer having the line head, the line head and the maintenance unit are arranged in parallel in the horizontal direction, and the nozzle of the line head faces downward during the image forming operation ( Then, during the maintenance operation, the line head is rotated around the horizontal axis so that the nozzles face the maintenance unit. In this state, a predetermined maintenance operation is performed.

However, with the line head maintenance unit, there is a risk that air enters the nozzles as the line head rotates. When air enters the nozzles as described above, when the image forming operation is restarted after the maintenance operation is completed, there is a possibility that a printing defect may be caused by the influence of the remaining air. In addition, there is a region where no ink is present in the nozzle, and when power is supplied to the drive electrodes provided in the nozzle, the temperature in this region may rise abnormally and the head may be damaged. is there.

In order to solve such a problem caused by the rotation of the line head, Japanese Patent Application Laid-Open No. H11-29151 has been proposed.
Japanese Patent Laid-Open Publication No. 1 (1999) -125 discloses a configuration in which a line head and a maintenance unit are arranged to face each other with a platen interposed therebetween. During the maintenance operation, the platen is retracted from the position facing the line head so that the line head and the maintenance unit face each other, and the maintenance unit is moved forward to perform the maintenance operation on the line head.

[0010]

However, as described above, when the platen is retracted from the position facing the line head during the maintenance operation, a space for retracting the platen must be provided, and the printer needs to have a space. There was a possibility that the size would be increased. In addition, complicated mechanisms such as a mechanism for moving the platen between the initial position and the retreat position and a mechanism for advancing the maintenance unit toward the line head are required. Accordingly, the platen returned from the retracted position to the predetermined position may not be located at the predetermined initial position. In this case, the distance between the nozzles of the line head and the platen cannot be obtained properly. As a result, the distance between the nozzles and the paper during the image forming operation is not set properly, leading to deterioration of image quality. Would.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and has as its object to reduce the size of the entire printer, to ensure the reliability of image forming operations, and to provide an inkjet printer having a line head. It is an object of the present invention to provide a configuration capable of performing a good maintenance operation.

[0012]

Means for Solving the Problems-Summary of the Invention-In order to achieve the above object, the present invention provides an endless belt capable of running as a means for maintaining a line head, and runs the endless belt. By doing so, it is possible to switch between a state in which the belt surface for maintenance faces the line head and a state in which the belt surface for paper conveyance (sheet material conveyance) faces the line head.

-Solution Means- Specifically, the present invention includes a line head having a plurality of ink nozzles arranged in a direction orthogonal to a sheet material conveying direction, and a sheet material conveying operation and ink ejection from the ink nozzles. An ink jet printer that forms a predetermined image on a sheet material surface by operation is assumed. This ink jet printer is provided with an endless belt that can run with its outer surface facing the line head, and a platen member that comes into contact with the inner surface of the endless belt. The sheet material is conveyed during the image forming operation in a state where a predetermined area on the outer surface of the endless belt faces the line head and the sheet material is brought into contact with the predetermined area. The operation is performed in a state where the line head is opposed to another predetermined region of the outer surface of the device.

According to this specific matter, when performing the maintenance operation after the end of the image forming operation, it is only necessary to run the endless belt and make a predetermined area of the endless belt face the line head. That is, there is no need to perform an operation of retracting the platen from the line head. For this reason, it is not necessary to provide a space for retracting the platen in advance, and the printer does not become large. Further, it is possible to switch between a state in which an image forming operation is performed by a relatively simple mechanism such as running of an endless belt and a state in which a maintenance operation is performed.

As the material of the endless belt, a foamable member capable of temporarily holding ink and having air permeability is employed. For this reason, when the inside of the platen is
Negative pressure also acts on the surface of the endless belt, which allows the sheet material to be conveyed while being sucked, thereby performing an image forming operation. In addition, during the maintenance operation, the collected ink to be discarded can be held in the endless belt, so that the collected ink can be prevented from being scattered in the apparatus.

The surface of the endless belt is divided into a plurality of areas. The details are as follows. First, a part of the surface of the endless belt is used as a sheet material transport area facing the line head when the sheet material is transported. Also,
A part of the surface of the endless belt is used as a maintenance area facing the line head during maintenance of the line head. In other words, the image forming operation is enabled by running the endless belt so that the sheet material conveyance region faces the line head, while the maintenance operation is performed by running the endless belt so that the maintenance region faces the line head. Making it possible. That is, the surface of the endless belt can be divided into two functional areas, and it is possible to reliably prevent the area that is soiled by the maintenance operation from coming into contact with the sheet material during the image forming operation, thereby avoiding soiling of the sheet material.

As a configuration for performing a so-called face wiping step during a maintenance operation, a blade is provided on the surface of the endless belt for wiping and cleaning the surface of the ink nozzles as the endless belt runs during maintenance of the line head. That is, only by running the endless belt during the maintenance operation, the surface of the ink nozzle is wiped off by the blade, and the surface of the ink nozzle can be cleaned.

In the case where the endless belt is provided with a position adjusting mechanism so that the belt surface can be moved between a position where the belt surface is in contact with the line head and a position where the belt surface is separated from the line head, the endless belt caps the line head. Thus, natural drying of the ink can be prevented. Further, when the endless belt is separated from the line head during the face wiping step, the amount of deflection of the blade during face wiping can be suppressed, and when the blade separates from the line head, the collected ink is scattered due to its elasticity. It is also possible to avoid situations such as getting lost.

Further, maintenance means is disposed on the opposite side of the line head with the endless belt interposed therebetween, and the maintenance means can be moved between a position in contact with the endless belt and a position separated from the endless belt. Is provided with a position adjusting mechanism. Accordingly, at the time of the maintenance operation, by bringing the maintenance means into contact with the endless belt, the ink collected on the endless belt can be discarded via the maintenance means.

The maintenance means is connected to a suction means for making the inside of the maintenance means a negative pressure. Further, the suction means is configured to apply a negative pressure to the inside of the maintenance means when a predetermined area of the outer surface of the endless belt on which the ink adheres comes into contact with the maintenance means during maintenance of the line head. . This allows
The ink collected by the endless belt can be easily introduced into the maintenance means, the efficiency of ink collection can be improved, and the maintenance operation can be performed efficiently.

Further, the suction means contacts the maintenance means when a predetermined area of the outer surface of the endless belt to which ink has adhered has contacted the maintenance means during maintenance of the line head and during the image forming operation. At this time, the inside of the maintenance means is configured to have a negative pressure. According to this, not only the maintenance operation can be performed efficiently as described above, but also the negative pressure acts on the surface of the endless belt via the platen member, and the floating phenomenon of the sheet material during the image forming operation can be avoided. . For this reason, the distance between the line head and the sheet material is set appropriately, and good image quality can be secured.

The following two types are set as the setting of the running direction of the endless belt. First, the conveying direction of the endless belt is set parallel to the conveying direction of the sheet material. Further, the transport direction of the endless belt is set to a direction orthogonal to the transport direction of the sheet material. In the former case, it is sufficient to secure an area only in the width direction of the line head (sheet material conveyance direction) as the maintenance area, and it is possible to set a shorter span length required for the endless belt. . On the other hand, in the latter case, the practicality in performing the face wiping step can be improved. This is because generally, in a line head, ink nozzles for ejecting ink of the same color are arranged in the longitudinal direction of the head. For this reason, in the case of the latter configuration, different inks do not mix on the blade, and even if the ink on the blade adheres to the ink nozzle side, it is different from the ink ejected from the nozzle. It is possible to prevent the color ink from adhering to the ink ejection port and causing image deterioration due to color mixture during image formation after maintenance.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a case where the present invention is applied to a color inkjet printer will be described.

First, the structure of the color ink jet printer 1 will be described with reference to FIGS. 1 and 2. FIG. FIG.
1 is a perspective view showing the appearance of a color inkjet printer 1. FIG. FIG. 2 is a schematic diagram showing the internal structure of the color inkjet printer 1.

In the color ink jet printer 1, a paper feed cassette 3 is provided on the front side (right side in FIG. 2) of the cabinet 2, and a paper discharge tray 4 is provided above the paper feed cassette 3 on the front side. ing.

On the other hand, as shown in FIG.
, A pickup roller 5, a paper feed roller 11, pinch rollers 12, 12, 12 that come into contact with the paper feed roller 11 from the paper feed cassette 3 to the paper discharge tray 4.
A PS roller (not shown), an image forming mechanism 6, a first pair of discharge rollers 13, a drying unit 14, and a second pair of discharge rollers 15 are sequentially provided.

The pickup roller 5 is a roller having a half-moon shape in cross section.
One of the recording sheets P as a sheet material stored in the recording paper P is taken out. The paper feed roller 11 and the pinch roller 12 transport the recording paper P taken out by the pickup roller 5 toward the image forming mechanism 6. The PS roller is directed to the image forming mechanism 6 so that the timing of starting the ink ejection from the ink head (line head) 61 provided in the image forming mechanism 6 and the timing of feeding the recording paper P to the image forming mechanism 6 are matched. The recording paper P is sent out. Each paper discharge roller pair 1
Numerals 3 and 15 convey the recording paper P after image formation toward the discharge tray 4. The drying unit 14 is for quickly drying the ink droplets on the recording paper P by means such as blowing hot air toward the surface of the recording paper P after image formation.

Next, the image forming mechanism 6, which is a feature of the present embodiment, will be described. This image forming mechanism 6
A line head 61 is provided which extends in a direction perpendicular to the paper surface of FIG. The image forming mechanism 6 has an ink tank (not shown) that individually stores Bk (black), C (cyan), M (magenta), and Y (yellow) inks.

The line head 61 is provided with a plurality of ink nozzles connected to a supply path extending from each ink tank. In the ink nozzles, ink nozzles that eject ink droplets of the same color are arranged side by side in the direction in which the line head 61 extends (the direction orthogonal to the plane of FIG. 2).

As shown in FIG. 3, the image forming mechanism 6 includes a belt mechanism 62 disposed below the line head 61, a platen 63, and a maintenance unit 64 as maintenance means. Hereinafter, each of these members will be described.

The belt mechanism 62 includes a pair of rollers 62 a, 62 a disposed upstream and downstream in the sheet conveying direction with respect to the position where the line head 61 is disposed.
2a, 62a and an endless belt 62b stretched over the endless belt 62a. As shown in FIG. 4, the pair of rollers 62a,
Drive force of a drive motor 62d can be transmitted to one of the gears 62a via a gear 62c, and the belt 62b can run along the sheet conveyance direction by rotation of the roller 62a accompanying the transmission of the drive force. Has become. As shown in FIG. 5 (an enlarged view of a portion V in FIG. 3), the belt 62b is made of a gas-permeable foam member (for example, NB).
R or foamed rubber of silicon rubber). The material of the foamable member is not limited to this. Therefore, when a negative pressure from a platen 63 described later acts on the belt 62b, the surface of the belt is also in a negative pressure state, whereby the recording paper P can be sucked. Also, during the maintenance operation described later,
Excess ink (ink to be discarded in a brim discharging process and a face wiping process described later) can be held inside the belt 62b.

A rubber blade 62e is attached to the surface of the belt 62b. The blade 62e is provided upright over substantially the entire width of the belt 62b, and its tip is slightly curved. During the maintenance operation, the curved portion wipes off the ink nozzle surface of the line head 61 as the belt 62b travels. Dimension t in FIG.
Numeral 1 is set to be equal to the distance between the line head 61 and the belt 62b during the maintenance operation, and a portion having a dimension t2 is a portion that contacts the ink nozzle surface of the line head 61 and performs a face wiping operation during the maintenance operation.

Further, the surface of the belt 62b is divided into a sheet conveyance area A as a sheet material conveyance area facing the line head 61 during image formation, and a maintenance area B facing the line head 61 during maintenance operation. (See FIG. 3). That is, the traveling of the belt 62b accompanying the driving of the driving motor 62d causes the sheet transport area A
Can be switched between a state in which the maintenance area B faces the line head 61 and a state in which the maintenance area B faces the line head 61. FIG. 3 shows a state in which the sheet transport area A faces the line head 61.

As shown in FIG. 4, the belt mechanism 62 is provided with an elevating mechanism 66 for moving the entire belt mechanism up and down. The elevating mechanism 66 includes a driving motor 66a, and a driving force of the driving motor 66a is transmitted to a gear 66b.
And an eccentric cam 66c transmitted through the eccentric cam 66c. The eccentric cam 66c is located below the shaft 62f of the roller 62a, rotates with the driving of the drive motor 66a, and rotates as shown by a solid line in FIG.
The belt mechanism 62 can be moved between a position separated from the position 2f and a position where the entire belt mechanism 62 is raised by pushing up the shaft 62f of the roller 62a as indicated by a virtual line in FIG. When the entire belt mechanism 62 is lifted, the upper surface of the belt 62b comes into contact with the ink nozzle of the line head 61 to cap the ink nozzle. When the belt mechanism 62 is in a lowered state (a state shown by a solid line in FIG. 4) in which the eccentric cam 66c is separated from the shaft 62f of the roller 62a, the distance between the ink nozzle of the line head 61 and the upper surface of the belt 62b is changed. Is set to an appropriate distance (a distance at which image formation by ejection of ink droplets is appropriately performed).

As shown in FIGS. 3 and 6 (a sectional view taken along line VI-VI in FIG. 3), the platen 63 is provided between the rollers 62a of the belt mechanism 62 and inside the belt 62b. The upper surface and the lower surface thereof are in contact with the inner surface of the belt 62b facing each other. The platen 63 has suction holes 63a, 63a,... Penetrating from the upper surface to the lower surface.
Thereby, when a negative pressure acts on the platen 63, the negative pressure can be applied to the belt surface via the suction holes 63a, 63a,.

The maintenance unit 64 is a rectangular parallelepiped member having a hollow inside. As shown in FIG. 7 (a is a side view, b is a plan view), a large number of holes 64a, .. Are formed (only a part of the holes 64a is shown in FIG. 7B). Further, a suction pump 65 as suction means is connected to the maintenance unit 64 via a suction pipe 64b. That is, the inside of the maintenance unit 64 becomes negative pressure by the driving of the suction pump 65, and the suction of the recording paper P and the collection of ink can be performed using this negative pressure. That is, the maintenance unit 64 has both the function of collecting waste ink and the function of applying a negative pressure to the surface of the belt 62b. The specific operation will be described later.

The maintenance unit 64 is also provided with an elevating mechanism 67 for moving the entire unit up and down. The elevating mechanism 67 includes a drive motor 67
a, an eccentric cam 67c for transmitting the driving force of the driving motor 67a via a gear 67b. Eccentric cam 6
7c is located opposite the lower surface of the maintenance unit 64, and rotates with the driving of the drive motor 67a.
As shown by the solid line in FIG.
7 and a position where the maintenance unit 64 is pushed upward as indicated by a virtual line in FIG. 7A. When the maintenance unit 64 is lifted, the upper surface of the maintenance unit 64 can contact the lower surface of the belt 62b. The contact between the maintenance unit 64 and the belt 62b is performed when the maintenance unit 64 moves up while the belt mechanism 62 is at the lowered position.

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

First, the basic operation of the image forming operation of the color ink jet printer 1 will be described. When the printing operation of the present color inkjet printer 1 is started, first, one of the recording sheets P stored in the sheet feeding cassette 3 is picked up by the pickup roller 5.
Paper feed roller 11 and pinch roller 1
2 transported. After that, this recording paper P is
The leading edge of the sheet is aligned with the image information by the rollers, and the sheet is conveyed to an image forming position facing the line head 61. When the recording sheet P passes through the image forming position, ink droplets of each color are individually ejected from each nozzle provided in the line head 61 based on the position and the image information of the recording sheet P, so that recording is performed. Image formation is performed on the upper surface of the sheet P.

The recording paper P on which an image is formed over substantially the entire surface is discharged toward the discharge tray 4 by the discharge roller pairs 13 and 15 while the drying unit 14 performs the drying operation of the ink droplets. Is done. As a result, the recording paper P on which a predetermined image has been formed is discharged to the discharge tray 4 in a face-up state (a state in which the image forming surface faces upward).

Next, the operation which is a feature of this embodiment will be described. This operation includes an operation when the color inkjet printer 1 is powered on and an operation when an image is formed. First, the operation when the power is turned on will be described with reference to the flowchart in FIG. 8 and FIGS. 9 and 10.

First, when power is turned on in step ST1, it is determined in step ST2 whether the belt mechanism 62 and the maintenance unit 64 are at the home position. This home position is shown in FIG.
As shown in (a), the belt mechanism 62 is in the raised position, the maintenance area B of the belt 62b is capping the line head 61, and the maintenance unit 64 is in the lowered position. If the belt mechanism 62 and the maintenance unit 64 are not at the home position, the process proceeds to step ST3, where they are temporarily moved to the home position. In step ST4, it is determined whether or not the initial maintenance operation of the ink nozzle is necessary in a state where the belt mechanism 62 and the maintenance unit 64 are at the home position.
This determination is made, for example, as to whether or not the elapsed time since the previous maintenance was performed has exceeded a predetermined time, whether or not the cumulative amount of ink discharge has exceeded a predetermined amount, and whether or not the cumulative number of ink discharges has exceeded a predetermined number of times. It is performed by determining whether or not. Here, when it is determined that the initial maintenance operation is unnecessary, the apparatus waits while the belt mechanism 62 and the maintenance unit 64 are at the home position, and waits for an image forming request.

On the other hand, if it is determined that the initial maintenance operation is necessary, the process proceeds to step ST5,
As shown in (a), the belt mechanism 62 is moved down together with the platen 63 by driving the elevating mechanism 66 to separate the belt 62 b from the line head 61. Then, step S
At T6, the operation proceeds to the maintenance operation of the line head 61. In this maintenance operation, in the state shown in FIG. 10A, a brim discharging step for forcibly discharging ink droplets from each ink nozzle, and the belt mechanism 62 is driven as shown in FIG. , The face wiping step of wiping the surface of the ink nozzle by the blade 62e is continuously performed.

Then, when the maintenance operation of the line head 61 is completed and YES is determined in step ST7, the process proceeds to step ST8, where the drive motor 62d is driven, and the maintenance area B is moved to the maintenance unit 64.
The belt 62b is caused to travel to a position opposite to. Then, the maintenance area B faces the maintenance unit 64, and if YES is determined in step ST9, in step ST10, as shown in FIG. 10C, the lifting mechanism 67 is driven to raise the maintenance unit 64. The upper surface of the maintenance unit 64 is
2b is brought into contact with the maintenance area B. In this state,
In step ST11, the suction pump 65 is driven, and the ink and the blade 62 existing in the maintenance area B are moved.
e. Aspirate and discard the ink adhering to e. If the suction and disposal of the ink are completed and YES is determined in step ST12, in step ST13, FIG.
As shown in (5), the elevation unit 67 is driven to lower the maintenance unit 64.
Is separated from the maintenance area of the belt 62b.

Thereafter, in step ST14, the drive motor 62d is driven, and as shown in FIG.
The belt 62b is moved to a position where the maintenance area B faces the line head 61. And step ST
In 15, the lifting mechanism 66 is driven again to raise the belt mechanism 62, and the line head 61 is capped by the maintenance area B of the belt 62 b (FIG. 9).
(State (a)), and waits in this state to wait for an image forming request. The above is the operation when the power is turned on.

Next, the operation during image formation will be described with reference to the flowchart of FIG. If it is determined that an image forming request has been made by receiving an image data signal from an image processing device (not shown) (a personal computer or the like) (step ST21), in step ST22, as in step ST2, the belt mechanism 6
2 and whether the maintenance unit 64 is at the home position. Thereafter, the above steps ST3 to ST3 are performed.
The same operation as in step ST13 is performed in steps ST23 to ST33. That is, after the maintenance operation of the line head 61 is performed in the brim discharging step and the face wiping step, the ink collected by the belt 62b is sucked and discarded by the maintenance unit 64.

On the other hand, when it is determined in step ST24 that the maintenance operation of the line head 61 is unnecessary, in step ST34, the lifting mechanism 6
6 is driven to lower the belt mechanism 62 at the home position, and at step ST35, the drive motor 62
d is driven to move the belt 62b to a position where the sheet transport area A of the belt 62b faces the line head 61. As a result, the state shown in FIG. 9B is obtained.

In step ST36, the elevating mechanism 67 is driven to raise the maintenance unit 64, and the belt 6
The maintenance unit 64 is brought into contact with the lower surface of 2b (the state shown in FIG. 9C). Then, step ST37
Then, the suction pump 65 is driven. As a result, the inside of the maintenance unit 64 and the platen 63 becomes negative pressure, and this negative pressure also acts on the surface of the belt 62b.
Thereby, the recording paper P conveyed at the time of image formation can pass through the image forming mechanism 6 in a state of being sucked on the surface of the belt 62b.

In this state, in step ST38,
The image forming processing operation described above is performed. In this image forming processing operation, the recording sheet P is conveyed without running the belt 62b, that is, while sliding on the surface of the belt 62b while sucking the surface of the belt 62b. Also, a large paper transport area A is secured, and the belt 62
The recording paper P may be conveyed while traveling b. In this case, it is necessary to set the traveling position of the belt 62b so that the recording paper P conveyed to the image forming mechanism 6 does not contact the maintenance area B of the belt 62b.

During this image forming process, it is determined in step ST39 whether or not an ink nozzle requiring maintenance (for example, an ink nozzle for which an ink ejection operation has been performed the required number of times) has occurred. If no ink nozzles are generated, in step ST40, it is determined whether or not image information of the next page exists. If the image information of the next page exists (YES), the process returns to step ST38, and the above-described image forming process is repeated. On the other hand, if the image information of the next page does not exist, that is, if the image forming process has been completed, step ST
In 41, the suction pump 65 is stopped, and the elevating mechanism 67 is driven to lower the maintenance unit 64.

On the other hand, if an ink nozzle requiring maintenance is generated during the printing process, the process proceeds to step ST42.
, It is determined whether or not the image forming operation on the paper being printed is completed. That is, it is determined whether or not a page unit break has occurred in the image forming operation.
In the case of, the process proceeds to step ST43 where the suction pump 6
5 is stopped, and the elevating mechanism 67 is driven to lower the maintenance unit 64. Then, step ST
Returning to 25, the same maintenance operation as described above is performed.
In this way, a continuous image forming operation according to the image information is performed while the maintenance operation of the line head 61 is periodically performed.

-Effects of Embodiment- As described above, in this embodiment, a belt mechanism 62 having a movable belt 62b is employed as a means for maintaining the line head 61, and a platen is provided inside the belt mechanism 62. 63, and a maintenance unit 64 is disposed below the 63. By running the belt 62b, the state in which the belt surface for maintenance (the maintenance area B) faces the line head 61 and the state in which the belt surface for paper transport (the paper transport area A) is in the line head 61. And the state opposite to. Conventionally, the platen is retracted from the line head so that the maintenance unit faces the line head.
A state in which the maintenance operation can be performed only by running the vehicle 2b can be achieved. Therefore, it is not necessary to provide a space for retracting the platen in advance, and the printer can be downsized. In addition, since it is possible to switch between a state in which an image forming operation is performed and a state in which a maintenance operation is performed with a relatively simple mechanism and operation such as running of the belt 62b, the distance between the nozzles and the paper during image formation is changed. , And good image quality can be stably obtained without the problem that the image is not properly obtained.

Further, since the negative pressure generated by the suction pump 65 can be used for sucking the paper and collecting the ink, the floating phenomenon of the recording paper P can be avoided, and the good image quality can be stabilized. In addition, waste ink can be efficiently collected.

-Other Embodiments- In the embodiments described above, the case where the present invention is applied to the color inkjet printer 1 has been described. The present invention is not limited to this, and can be applied to a monochrome type inkjet printer.

In the embodiment described above, the belt mechanism 62 in which the transport direction of the belt 62b is set parallel to the paper transport direction.
However, the present invention is not limited to this, and the belt 62b may be set in a direction perpendicular to the sheet transport direction. In this case, different inks do not mix with each other on the blade 62e, and even if the ink on the blade 62e adheres to the ink nozzle, ink of a different color from the ink ejected from the nozzle is ejected. It does not adhere to the outlet and cause image deterioration due to color mixing at the time of image formation after maintenance.

Although the maintenance unit 64 is also made to function as a means for applying a negative pressure to the surface of the belt 62b, the platen 63 is provided with individual suction means, and the platen 63 is driven by driving this suction means. 6
A negative pressure may be applied to the inside of the belt 62b, thereby applying a negative pressure to the surface of the belt 62b.

[0057]

As described above, according to the present invention, a movable endless belt is provided as a means for maintaining the line head, and by running the endless belt, the surface of the belt for maintenance is reduced. And a state in which the belt surface for conveying the sheet material is opposed to the line head. Therefore, there is no need to perform an operation of retracting the platen from the line head, and accordingly, it is not necessary to provide a space for retracting the platen in advance. As a result, the size of the printer can be reduced. In addition, it is possible to switch between a state in which an image forming operation is performed and a state in which a maintenance operation is performed with a relatively simple mechanism and operation such as running of an endless belt. Good image quality can be stably obtained without an appropriate distance being obtained, and the reliability of the printer can be improved.

Further, since the surface of the endless belt is divided into a sheet material transport area and a maintenance area, it is ensured that an area (maintenance area) that is soiled by the maintenance operation comes into contact with the sheet material during the image forming operation. Thus, the sheet material can be prevented from being stained, and a good printed material (image-formed sheet material) can be obtained.

Further, since a position adjusting mechanism for adjusting the position of the endless belt with respect to the line head and adjusting the position of the maintenance means with respect to the endless belt is provided, these are adjusted to positions suitable for performing the image forming operation and the maintenance operation. Each member can be arranged, and each operation can be performed favorably.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an appearance of a color inkjet printer according to an embodiment.

FIG. 2 is a schematic diagram showing an internal structure of the color inkjet printer.

FIG. 3 is a diagram illustrating an image forming mechanism.

FIG. 4 is a diagram illustrating a driving unit of the image forming mechanism.

FIG. 5 is an enlarged view of a portion V in FIG.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 3;

FIG. 7 is a diagram showing a maintenance unit,
(A) is a side view, (b) is a plan view.

FIG. 8 is a flowchart for explaining the operation when the power is turned on.

FIG. 9 is a diagram illustrating a part of an operation state of a belt mechanism and a maintenance unit.

FIG. 10 is a diagram showing another part of the operation state of the belt mechanism and the maintenance unit.

FIG. 11 is a flowchart for explaining an operation at the time of requesting image formation.

[Explanation of symbols]

Reference Signs List 1 color inkjet printer 61 line head 62b belt (endless belt) 62e blade 63 platen 64 maintenance unit (maintenance means) 65 suction pump (suction means) 66, 67 lifting mechanism (position adjustment mechanism) A paper transport area (sheet material transport area) ) B Maintenance area

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B65H 5/22 B41J 3/04 102H F-term (Reference) 2C056 EA16 FA13 HA29 JB05 2C059 AA02 AA11 AA29 3F049 AA03 BA02 BA04 BA11 FB00 LA07 LB03

Claims (12)

[Claims] A line head having a plurality of ink nozzles arranged side by side in a direction orthogonal to a sheet material conveying direction, wherein a predetermined image is formed on a sheet material surface by a sheet material conveying operation and an ink discharging operation from the ink nozzles. An ink jet printer for forming, comprising: an endless belt capable of running with an outer surface facing the line head; and a platen member abutting on an inner surface of the endless belt, for conveying a sheet material during an image forming operation. Is performed in a state in which a predetermined area on the outer surface of the endless belt faces the line head and the sheet material contacts the predetermined area, while another predetermined area on the outer surface of the endless belt is used during maintenance of the line head. An ink jet printer characterized in that the ink jet printer is configured to be performed in a state facing the ink jet printer. 2. The ink-jet printer according to claim 1, wherein the endless belt is made of a gas-permeable foam member capable of temporarily holding ink and having air permeability. 3. The ink jet printer according to claim 1, wherein a part of the surface of the endless belt is a sheet material transport area facing the line head when the sheet material is transported. 4. The ink jet printer according to claim 1, wherein a part of the surface of the endless belt is a maintenance area facing the line head during maintenance of the line head. 5. The ink jet printer according to claim 1, wherein the surface of the endless belt is cleaned by wiping the surface of the ink nozzle as the endless belt runs during maintenance of the line head. An ink-jet printer comprising a blade. 6. The ink jet printer according to claim 1, wherein the endless belt is movable between a position where the belt surface contacts the line head and a position where the belt surface is separated from the line head. An ink jet printer, comprising a position adjusting mechanism. 7. The ink jet printer according to claim 1, wherein a maintenance means is provided on a side opposite to the line head with the endless belt interposed therebetween. An ink jet printer comprising a position adjusting mechanism provided to be movable between a position contacted with the endless belt and a position separated therefrom. 8. The ink jet printer according to claim 7, wherein the maintenance means is connected to a suction means for making the inside of the maintenance means a negative pressure. 9. The ink jet printer according to claim 8, wherein the suction means is provided when the predetermined area of the outer surface of the endless belt to which the ink adheres comes into contact with the maintenance means during maintenance of the line head. An ink jet printer, wherein the inside is configured to have a negative pressure. 10. The ink jet printer according to claim 8, wherein the suction means is provided when a predetermined area of the outer surface of the endless belt to which ink adheres comes into contact with the maintenance means during maintenance of the line head and during an image forming operation. An ink jet printer, wherein when the endless belt comes into contact with the maintenance means, a negative pressure is applied to the inside of the maintenance means. 11. The ink jet printer according to claim 1, wherein the conveying direction of the endless belt is set in parallel with the conveying direction of the sheet material. 12. The ink jet printer according to claim 1, wherein a conveying direction of the endless belt is set to a direction orthogonal to a conveying direction of the sheet material. Inkjet printer.