JPH0911502A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute the emission restoring operation of a head within a short time even on the way of recording to shorten the total recording time and to eliminate an increase in the width of an apparatus caused by the mounting of an emission restoring mechanism to prevent the lowering of the connection accuracy between image bands caused by emission restoring operation. SOLUTION: A restoring means 62 is integrally provided to a carriage 54 loaded with an ink jet head 51 and the ink jet head 51 can be shaken between the recording position 72 opposed to the surface of a rotary drum 10 and the non-recording position opposed to the restoring means 62 centering around a carriage rail 52. On the way of this shaking route, a head cleaning wiper blade 64 is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image on a recording material by a recording means, and more particularly, while an inkjet head scans the recording material on a rotary drum in the axial direction of the rotary drum. The present invention relates to an image forming apparatus that forms an image.

[0002]

2. Description of the Related Art An image forming apparatus having functions such as a printer, a copying machine, and a facsimile, or an image forming apparatus used as an output device of a multifunction machine or a workstation including a computer, a word processor, and the like, prints a sheet based on image information. An image (including characters and symbols) is formed (recorded) on a recording material (recording medium) such as a thin plastic plate (sheet for OHP). The recording system of the image forming apparatus can be classified into, for example, an electrophotographic system, an inkjet system, a wire dot system, a heat sensitive system, a thermal transfer system, a laser beam system and the like.

In a serial type image forming apparatus in which recording is performed while performing main scanning in a direction intersecting the conveying direction or the rotating direction (sub-scanning direction) of the recording material, the recording material is set at a predetermined recording position. After that, an image (including characters and symbols) is recorded by a head mounted on a carriage that moves along the recording material, and recording for a predetermined width and paper feed for a predetermined amount (sub scanning) are synchronized. An image is formed on the recording material by executing the process. On the other hand, in a line-type image forming apparatus that prints a recording material only in the sub-scanning direction in which the recording material is fed in the transport direction, the recording material is set at a predetermined recording position, and the image formation for one line is continuously performed. An image is formed on the recording material by feeding a predetermined amount of paper while performing the operation.

The above-mentioned ink jet type image forming apparatus records by ejecting ink onto a recording material from an ink jet head as a recording means, the head can be easily made compact, and a high-definition image can be formed at high speed. Can be used to record on plain paper without any special treatment, low running cost, low noise due to non-impact method, and color can be obtained by using multi-color ink. It has advantages such as easy recording of images. Above all, a line-type image forming apparatus using a line-type recording head in which a large number of ejection openings are arranged in the paper width direction can further speed up image formation.

In particular, an ink jet type recording head for ejecting ink by utilizing thermal energy is an electrothermal converter, an electrode, a liquid formed on a substrate through a semiconductor manufacturing process such as etching, vapor deposition and sputtering. Road wall,
By forming a top plate, etc., it is possible to easily manufacture a product having a high-density liquid passage arrangement (ejection arrangement),
Further compactness can be achieved. Further, by utilizing the advantages of IC technology and micro processing technology, it is easy to make the recording means long and planar (two-dimensional), and it is also easy to make the recording means full-multi and high-density mounting. is there.

7 and 8 are perspective views of a conventional example of an image forming apparatus such as a printer, a facsimile or a copying machine which forms an image by scanning an ink jet head relative to a recording material. FIG. 7 shows a conventional example of a type in which a recording material is moved in a plane. The image forming apparatus shown in FIG. 7 includes an inkjet head 51 that discharges ink for recording, and a carriage 54 that supports the inkjet head 51 and moves in a direction perpendicular to the feeding direction of the recording material 2.
And a carriage rail 52 and an auxiliary rail 55 that guide and support the reciprocating movement of the carriage 54.

Further, the image forming apparatus of FIG. 7 has a carriage motor 59 for driving the carriage 54, a pulley 66 directly connected to the carriage motor 59, and a pulley 66.
And an idler pulley 67 facing each other and a pulley 6 for transmitting the power of the carriage motor 59 to the carriage 54.
6 and a carriage belt 58 wound around the idler pulley 67.

The image forming apparatus shown in FIG. 7 further includes a paper feed motor 68 for feeding the recording material 2 such as paper,
A cap 6 for preventing the ejection port of the inkjet head 51 from drying during non-recording and protecting the ejection port surface.
3, a conveying roller 69 for feeding the recording material 2, a pressing roller 70 for pressing the recording material 2 against the conveying roller 69 by a biasing means (not shown), and a position between the cap 63 and the recording material 2. Then, a preliminary ejection box 71 for receiving ink (preliminary ejection ink or the like) ejected from the inkjet head 51 other than recording is provided.

In the vicinity of the preliminary ejection box 71, a wiping member (not shown) for wiping off the ink adhered on the ejection port surface which hinders proper ink ejection is provided. The wiping member is usually formed of a plate-shaped member made of an elastic material such as rubber. A double-headed arrow a indicates the reciprocating direction of the carriage 54, and an arrow b indicates the rotation direction of the carry roller 69.

The operation of recording with the image forming apparatus of FIG. 7 is as follows. When recording, cap 63
The ink jet head 51 whose ejection port is protected by is separated from the cap 63. Next, the power from the carriage motor 59 is transmitted to the carriage 54 via the carriage belt 58 wound around the pulley 66 and the idler pulley 67. As a result, the carriage 54 is driven, and the moving direction and position of the carriage 54 are controlled.

The ink jet head 51 moves along with the carriage 54 onto the recording material 2, scans along the recording material 2, moves over the surface of the recording material 2 over a predetermined distance, and then in the direction of the cap 63. Reverse the moving direction. During this movement, the inkjet head 51 reciprocates in the direction of the double-headed arrow a and ejects ink droplets to a predetermined position on the recording material 2 to record an image. The recording material 2 is
Every time one scan of the inkjet head 51 is completed, the paper is fed by the paper feed motor 68 and the feed roller 69 in the direction of arrow b by a predetermined length. Recording is performed by repeating these operations.

In the case of a so-called on-demand type head in which the ejection from the ejection port of the ink jet head 51 is selectively performed at the time of this recording, the time interval from one ejection to the next ejection is large depending on the image. In some cases, there is a discharge port. In such an ejection port, the viscosity of the ink in the vicinity of the ejection port increases during that period, which hinders normal ejection. In order to prevent this, ink is regularly ejected even during non-recording. The preliminary ejection box 71 is for receiving ejection ink other than such recording.

The preliminary discharge box 71 is arranged at a position outside the position (recording area) on the recording material 2, for example, at a position between the cap 63 and the recording material 2. Therefore, in order to perform the preliminary ejection, the inkjet head 5 is moved to the position of the preliminary ejection box 71 by scanning the carriage 54.
It is necessary to move 1 to perform the preliminary discharge after the inkjet head 51 reaches the position of the preliminary discharge box 71. The preliminary discharge box 71 can be replaced with the cap 63.

Further, in order to maintain the normal recording operation, it is necessary to wipe off the ink and the ink mist adhering to the ejection port surface after the elapse of a certain time or after the preliminary ejection, and therefore the ejection of the ink jet head 51. A wiping member (not shown) for wiping and cleaning the outlet surface is provided. Usually, this wiping operation is performed about once for one recording material 2.

FIG. 8 is a schematic perspective view showing a conventional example of an image forming apparatus of a type different from that of FIG. Next, the image forming apparatus of FIG. 8 will be described. The image forming apparatus shown in FIG. 8 records on the recording material 2 wound (held) around the rotary drum 10.

Referring to FIG. 8, the image forming apparatus of this embodiment has an ink jet head 51 for recording by ejecting ink.
And a carriage 54 that carries the inkjet head 51 and reciprocates in the axial direction of the rotary drum 10 described below, and a carriage rail 52 and an auxiliary rail 55 that guide and support the reciprocating movement of the carriage 54.

Further, in the image forming apparatus of FIG. 8 as well, a carriage motor 59 for driving the carriage 54, a pulley 66 directly connected to the carriage motor 59, and a pulley 66.
And an idler pulley 67 facing each other and a pulley 6 for transmitting the power of the carriage motor 59 to the carriage 54.
6 and a carriage belt 58 wound around the idler pulley 67.

Further, the image forming apparatus of FIG. 8 has a rotary drum 10 for holding a recording material 2 mainly made of paper, and a paper feed unit connected to the rotary drum 10 for rotationally driving the rotary drum 10. A motor 68 and a cap 63 for preventing the ejection port of the inkjet head 51 from drying during non-recording and protecting the ejection port surface are provided. The cap 63 has the same function as that of FIG. 7, and also has the function of the preliminary discharge box 71 in FIG. 7.

Similar to the case of FIG. 7, a wiping member (not shown) is provided near the cap 63 for wiping off the adhered ink or the like on the ejection port surface which hinders proper ink ejection. . This wiping member is usually
It is formed of a plate-shaped member made of an elastic material such as rubber. A double-headed arrow a indicates the reciprocating direction of the carriage 54,
The arrow b indicates the rotation direction (sub-scanning direction) of the rotary drum 10.

The operation of recording with the image forming apparatus of FIG. 8 is as follows. When recording, cap 63
The ink jet head 51 whose ejection port is protected by is separated from the cap 63. Next, the power from the carriage motor 59 is transmitted to the carriage 54 via the carriage belt 58 wound around the pulley 66 and the idler pulley 67. As a result, the carriage 54 is driven, and the moving direction and position of the carriage 54 are controlled.

The inkjet head 51 moves together with the carriage 54 onto the recording material 2 and scans along the recording material 2. Further, the rotary drum 10 is rotated with the recording material 2 in the direction of arrow b at a predetermined peripheral speed by the power of the paper feed motor 68, and the inkjet head 51 discharges ink droplets to a predetermined position. Inkjet head 5
When 1 finishes recording with a constant width, the inkjet head 51 moves to the next recording position together with the carriage 54, and similarly performs recording with a constant width. Further, by repeating these steps, recording for one page is performed.

Further, in order to maintain the normal recording operation, it is necessary to wipe off the ink and the ink mist adhering to the ejection port surface after a lapse of a certain time or after the preliminary ejection. Therefore, the ejection of the ink jet head 51 is required. A wiping member (not shown) for wiping and cleaning the outlet surface is provided. After recording one page, the recording material 2 after recording is peeled from the rotary drum 10 and discharged to the outside of the apparatus.

[0023]

However, in the conventional example of FIG. 7, the recording material 2 is sandwiched by a pair of rollers such as a conveying roller and a pressing roller, and the recording head is moved while feeding the recording material 2 by a constant width. Since the image is formed on one recording material while reciprocating in the direction perpendicular to the recording material feeding direction, extra time is required for the return movement of the recording head. Is getting longer.

Further, if the moving speed at the time of the backward movement is increased, the electric power and noise are increased, or the motor is increased in size. Even when recording is performed in both forward and backward movements of the recording head, deceleration time and acceleration time for changing the traveling direction of the recording head are required, and the deviation of the recorded image due to backlash etc. is corrected. However, there is a disadvantage that the control of the recording operation becomes complicated.

Further, when a color ink jet head in which four recording heads are arranged in the order of black, cyan, magenta, and yellow in the head advancing direction is used as the recording means, ink is overlapped by forward and backward movements of the heads. Color misregistration occurs due to a different order, which makes reciprocal recording practically impossible and causes a longer recording time.

Further, in the structure as shown in FIG. 7, the cap 63 and the preliminary ejection box 71 must be provided outside the printing area, and the acceleration area is set in order to make the scanning speed of the carriage 54 during printing constant. Since it is necessary to provide a deceleration area and a carriage acceleration / deceleration area on both sides of the recording area, the size of the image forming apparatus in the carriage movement direction becomes large.

On the other hand, in the conventional example of FIG. 8, one recording material 2 is attached to each rotary drum 10 and the rotary drum 1
An image is recorded on the recording material 2 on the rotary drum 10 by rotating 0 and causing the inkjet head 51 to scan with the carriage 54 in the axial direction of the rotary drum 10, and after the recording is completed, the rotary drum 10 is recorded. The recording material 2 is peeled off from the apparatus and discharged to the outside of the apparatus.

According to the image forming apparatus of FIG. 8 having such a configuration, the rotary drum 10 rotates at a constant speed, and the ink jet head 51 and the carriage 54 are located on the rotary drum 10.
Since one page of image is recorded by intermittently moving in the axial direction of the rotary drum 10 by the recording width per rotation, reciprocation of the inkjet head 51 in the case of FIG. 6 and acceleration / deceleration at the time of reversing the inkjet head 51 are eliminated. , That much,
The recording operation itself can be speeded up.

However, in the image forming apparatus of FIG.
During the recording, the cap 63 should be installed in the place where ejection other than recording is possible.
Since there is nothing else, when a so-called on-demand type recording head that selectively ejects ink from the ejection port is used as the inkjet head 51, the time interval of ink ejection from the ejection port becomes long depending on the image, and in the meantime. The solvent of the ink in the vicinity of the ejection port may evaporate, causing an increase in viscosity (increased viscosity), resulting in defective ink ejection.

In particular, in the case of ink droplets when an image having a pixel density of 400 dots / inch is recorded, it is usually 30 to 60 pl.
While the ink droplet is about (picoliter), when a small droplet of about 5 to 15 pl is formed in order to record a higher quality image, the inkjet head 51
The area of the discharge port and the discharge energy are further reduced, and the above problem of discharge failure becomes more severe.

In order to solve this problem, a method of returning the ink jet head 51 to the position of the cap 63 at a predetermined timing and performing a preliminary ejection operation can be considered. However, extra time is required to return the inkjet head 51 to the position of the cap 63, and the features of the rotary drum type image forming apparatus aiming to shorten the recording time are impaired.

Further, when the recording paper size is large, or when image formation is performed by a plurality of passes for the purpose of achieving higher image quality, the longer the recording time is, the more wasteful the time is. There is also. Further, the longer the recording time is, the more the number of wiping operations is performed during recording on one recording material, and thus the more the number of operations of returning the inkjet head 51 to the position of the cap 63 is increased. There is also the problem that the time becomes longer.

Further, in the configuration shown in FIG. 8, the carriage 5
4 does not need to scan at a constant speed, and an area for accelerating and decelerating the carriage 54 is also unnecessary. Therefore, the size of the image forming apparatus in the carriage movement direction can be made smaller than that shown in FIG. However, in the configuration of FIG. 8, the cap 63 needs to be arranged next to the rotary drum 10, which is disadvantageous in the case of further downsizing the image forming apparatus.

The present invention has been made in view of the above technical problems, and an object of the present invention is to improve ink ejection performance due to an increase in ink viscosity even when a recording head having a minimum ejection opening area is used. Preliminary ejection can be performed at any time without causing any trouble, and even when the recording time becomes long, the ejection opening surface can be wiped (cleaned) immediately (immediately). An object of the present invention is to provide an image forming apparatus that can be downsized to the same extent as an apparatus that requires a short time for recording.

[0035]

In order to achieve the above object, the invention of claim 1 is an image forming apparatus for forming an image on a recording material by a recording means, wherein a rotating drum and the recording material are provided on the rotating drum. Holding means for holding, an inkjet head for forming an image by ejecting ink onto a recording material held on a rotary drum, a recovery means for recovering the function of the inkjet head, and an inkjet head in the axial direction of the rotary drum. A drive mechanism for scanning the head and the recovery means, a displacement mechanism for displacing the inkjet head to a position facing the recovery means, a paper feeding means for supplying the recording material to the rotary drum, and a recording target held on the rotary drum. Discharging means for discharging the material, and control for controlling the displacement mechanism by operating the displacement mechanism after a lapse of a predetermined time in the middle of recording And having a stage, a.

In the structure of claim 1, when a predetermined time is reached during recording, the displacement mechanism is operated to displace the ink jet head to a position facing the recovery means, and the recovery operation of the ink jet head ( In particular, the preliminary ejection operation) can be performed.

To achieve the above object, the invention of claim 2 is, in an image forming apparatus for forming an image on a recording material by a recording means, a rotating drum and a holding means for holding a plurality of recording materials on the rotating drum. Means, an inkjet head for forming an image by ejecting ink onto a recording material held on a rotary drum, a recovery means for recovering the function of the inkjet head, an inkjet head and recovery in the axial direction of the rotary drum. Drive mechanism for scanning the means, displacement mechanism for displacing the ink jet head to a position facing the recovery means, paper feeding means capable of simultaneously supplying a plurality of recording materials to the rotating drum, and a plurality of holding means held on the rotating drum. The ejecting means capable of ejecting the recording material at the same time and the recovery mechanism of the inkjet head by operating the displacement mechanism after a lapse of a predetermined time during recording. Characterized in that it has a control means for controlling the Migihitsuji.

Also in the second aspect of the invention, when the predetermined time is reached during recording, the displacement mechanism is operated to displace the ink jet head to a position facing the recovery means, and the recovery operation of the ink jet head ( In particular, the preliminary ejection operation) can be performed.

In order to achieve the above object, in the invention of claim 3, in addition to the structure of claim 1 or 2, the recovery means has an ink receiving portion for receiving the ink other than the recording ink ejected from the ink jet head. Is characterized by.

According to the third aspect of the invention, when a predetermined time is reached during recording, the displacement mechanism is operated to displace the ink jet head to a position facing the ink receiving portion of the recovery means, and the ink jet ink is ejected. A head recovery operation (particularly preliminary ejection operation) can be performed.

In order to achieve the above object, the invention of claim 4 is characterized in that, in addition to the constitution of claim 1, 2 or 3, the recovery means has a cap means for covering the ejection port surface of the ink jet head. And

In the structure of claim 4, in order to prevent the ejection port surface of the ink jet head from drying when the recording operation is not performed for a predetermined time during the recording,
By operating the displacement mechanism, the inkjet head can be displaced to a position facing the cap means of the recovery means, and the ejection port surface of the inkjet head can be capped.

In order to achieve the above object, in the invention of claim 5, in addition to the constitution of claim 1, 2, 3 or 4, a cleaning member for cleaning the ejection port surface of the ink jet head faces the recovery means. It is characterized in that it is arranged between the position and the recordable position.

According to the fifth aspect of the present invention, when a predetermined time is reached during recording, the displacement mechanism is operated to displace the ink jet head to a position facing the recovery means to recover the ink jet head. Further, the ejection port surface can be cleaned by the cleaning member by utilizing the movement of the inkjet head at that time.

In order to achieve the above object, in the invention of claim 6, in addition to the constitution of claim 1, 2, 3, 4 or 5, the standby position of the ink jet head when the image forming apparatus is not operating is It is characterized in that it is a position facing the recovery means. In the structure of claim 6, since the recovery system unit is not arranged adjacent to the rotary drum in the axial direction, it is possible to further reduce the size of the entire apparatus.

[0046]

Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals in each drawing indicate the same or corresponding parts. 1 is a vertical sectional view schematically showing the configuration of a first embodiment of an image forming apparatus to which the present invention is applied.
3 is a perspective view schematically showing a non-recording state of the image forming apparatus of FIG. 1, and FIG. 3 is a perspective view schematically showing a state of recording of the image forming apparatus of FIG.

1 to 3, a paper feed cassette 3 accommodating a recording material (recording medium) 2 such as recording paper or a plastic thin plate is detachably attached to the lower part of the apparatus main body 1. In FIG. 1, the recording materials 2 stacked in the paper feed cassette 3 are separated one by one from the uppermost layer by a paper feed roller 4 and a separation claw (not shown). 5 is conveyed. Reference numeral 6 denotes a manual feed tray for manual feeding, and the manual feed tray 6 is normally folded and stored in the apparatus main body 1 as shown in FIG.

In FIG. 1, reference numeral 7 is a switching guide. The switching guide 7 is located at the position shown by the solid line when the paper is fed from the paper feeding cassette 3, and is automatically opened when the manual feed tray 6 is opened. It is connected to the manual feed tray 6 so as to come to the position shown by the broken line. Reference numeral 8 is a registration roller pair. The recording material 2 that has passed through the paper feed guide 5 is corrected for skewing using the nip portion of the registration roller pair 8. In this way, the recording material 2 conveyed from the paper feed roller 4 or the manual feed guide 6 is conveyed to the rotary drum 10.

The rotary drum 10 is a drum for holding the recording material 2. For example, the rotary drum 10 has a diameter of 120 mm and a peripheral length of 377 mm, and is rotatably supported by the apparatus main body 1. The rotary drum 10 rotates in the direction of arrow b during recording. Reference numeral 14 is a tip gripper on the rotary drum 10. The recording material 2 that has passed through the registration rollers 8 and has been guided by the conveyance guide 9 is held on the rotating drum 10 by sandwiching the leading end of the recording material 2 with the leading end gripper 14.

During recording, the recording material 2 is held on the peripheral surface of the rotary drum 10 by static electricity. After the end of recording, the tip gripper 14 lifts the tip of the recording material 2 held on the rotary drum 10 from the drum surface to separate the claw 1 from the surface.
6 has a function of hooking the recording material 2 to separate the recording material 2 from the rotary drum 10. A rear end gripper 15 is provided on the rotary drum 10. This rear edge gripper 15
Is for preventing the trailing end of the recording material 2 from floating from the surface of the drum and coming into contact with the inkjet head 51.

The axial length of the rotary drum 10 is, for example, about 2
It is about 50 mm, and the front gripper 14 and the rear gripper 15 are parallel to the axial direction of the rotary drum 10 and, for example, about 2 mm.
It has a length of 50 mm. Such dimensions are A4
The size is suitable for holding one sheet of recording paper (recording material) of size in the vertical direction.

In the ink jet recording system, the recording material 2
When the recording material absorbs the ink and is deformed, the recording material may come into contact with the ejection port surface of the inkjet head 51 and stain the recording surface. In order to prevent this contact, the recording material 2
It is necessary to have some means for adsorbing the to the rotary drum 10. In this embodiment, the electrostatic attraction means is used as the attraction means for attracting and holding the recording material 2.

In FIG. 1, in order to provide the electrostatic attraction means, the rotary drum 10 is a drum cylinder 1 as a conductor having a thickness of about 5 mm made by cutting aluminum.
1 and an insulating sheet 12 fixed to the surface of the drum cylinder
It is composed of As the insulating sheet 12, for example, polyethylene terephthalate is used.
A charging roller 13 applies an electric charge to the recording material 2. In other words, because the drum cylinder 11 is grounded,
When a predetermined charge is applied to the recording material 2, an electrostatic attraction force acts between the recording material 2 and the insulating sheet 12, and the recording material 2 is attracted to the rotating drum 10. Will be retained.

In FIG. 1, the separation claw 16 and the conveyance guide 9
A cleaning roller 17 for wiping and cleaning the surface of the rotating drum 10 is disposed between the cleaning roller 17 and the roller. The cleaning roller 17 is arranged close to the rotary drum 10 and can come into contact with and separate from the rotary drum 10.
That is, after the recording is completed, the recording material 2 is separated by the separating claw 16.
After the cleaning is separated, the cleaning roller 17 is brought into contact with the peripheral surface of the rotary drum 10 to wipe off the dirt on the surface of the rotary drum 10.

When ink mist or the like adheres to the surface of the rotary drum 10, the suction force with respect to the recording material 2 is reduced or the recording material 2 to be adsorbed next is soiled. This is to eliminate inconvenience. 1 to 3, reference numeral 50 denotes an inkjet cartridge having a structure in which an ink tank and an inkjet head 51 are integrated. This inkjet head 51
On the ejection port surface (the surface facing the surface of the rotary drum 10), a plurality of ejection ports arranged substantially parallel to the rotation axis direction of the rotary drum 10 at the same pitch as the recording resolution are provided.

The ink jet head 51 is a recording head for ejecting ink by utilizing heat energy, and has an electrothermal converter for generating heat energy. Further, the ink jet head 51 ejects ink from an ejection port by utilizing a pressure change caused by growth and contraction of bubbles due to film boiling generated by thermal energy applied by the electrothermal converter, thereby forming an image. Is.

FIG. 4 is a partial perspective view schematically showing the structure of the ink ejection portion of the ink jet head 51.
In FIG. 4, the recording material 2 and a predetermined gap (for example, about 0.
A plurality of ejection openings 82 are formed at a predetermined pitch on the ejection opening surface 81 facing each other at a distance of about 5 to 2.0 mm), and the wall surface of each liquid passage 84 that connects the common liquid chamber 83 and each ejection opening 82. An electrothermal converter (heat generating resistor, etc.) 85 for generating energy for ejecting ink is disposed along the line.

In this example, the ink jet head 5
No. 1 is mounted on the carriage 54 in such a positional relationship that the plurality of ejection ports 82 are arranged substantially parallel to the scanning (moving) direction of the carriage 54. In this way, by driving (energizing) the corresponding electrothermal converter 85 based on the image signal or the ejection signal, the ink in the liquid passage 84 is film-boiling, and the ink is ejected from the ejection port 82 by the pressure generated at that time. The inkjet head 51 is configured.

1 to 3, a bearing portion 53 of a carriage rail 52 is provided on the upper side of the ink jet cartridge 50, and the ink jet cartridge 50 is fixed around the axis of the carriage rail 52 as shown by a double-headed arrow. It is supported so that it can freely swing (rotate) within an angle range. Also, the inkjet cartridge 5
0 is fixed to the carriage 54 in the axial direction of the carriage rail 52.

The carriage 54 is slidably (movably) guided and supported by the carriage rail 52 and an auxiliary rail 55 parallel to the carriage rail 52. Furthermore, a plunger 56 is mounted on the carriage 54, and the tip of the plunger 56 is connected to the inkjet cartridge 50. Therefore, by operating the plunger 56, the inkjet cartridge 50 is rotated between the position shown by the solid line and the position shown by the broken line in FIG. 1, and the position of the inkjet head 51 can be switched. There is.

Further, the belt connecting portion 5 is attached to the carriage 54.
7 is provided and is connected to the carriage belt 58. The carriage belt 58 is wound around a motor pulley 66 attached to a carriage motor 59 and an idler pulley 67 (not shown) arranged on the opposite side of the apparatus main body 1. Therefore, by driving the carriage motor 59 forward and backward, the carriage 54 can be reciprocated along the carriage rail 52 and the auxiliary rail 55.

In FIG. 1, the carriage 54 and the electrical component section 6
0 is electrically connected by a flexible cable (flexible) 61, and the carriage 54 and the inkjet cartridge 50 connect the cartridge 50 to the carriage 5.
When set to 4, contact with electrical contacts not shown,
It is configured to be electrically connected. As a result, an electrical signal from the electrical component unit 60 is transmitted to the inkjet cartridge 50, and the inkjet head unit 5
1 is driven and ink is ejected onto the recording material 2 to form (record) an image.

1 to 3, reference numeral 62 denotes a recovery system unit (recovery means). In this embodiment, the recovery system unit 62 is configured integrally with the carriage 54 and performs the same scanning (movement) as the scanning (movement) of the carriage. The inkjet head 5 is provided above the recovery system unit 62.
A cap 63 for sealing (capping) the first discharge port 82 is provided. By covering the ejection port surface 81 of the head 51 with the cap 63, the ink in the vicinity of the ejection port 82 is prevented from being dried, and the ejection port 82 is prevented from being clogged.

Reference numeral 64 is a wiper blade (cleaning member). The wiper blade 64 is mounted so that it can be projected from the recovery system unit 62 by a plunger (not shown). With the wiper blade 64 protruding, the ink jet cartridge 50 is swung about the carriage rail 52, so that foreign matter such as ink or dust attached to the ejection port surface 81 of the ink jet head 51 is removed by the wiper blade 64. It is configured so that it can be wiped off (cleaned).

Further, the recovery system unit 62 has a built-in pump for sucking the ink discharged into the cap 63 or the ink remaining in the discharge port 82 in order to recover the function of the ink jet head 51. The sucked ink is discharged to the waste ink pack 65 arranged below the entire range scanned by the recovery system unit 62. The waste ink pack 65 is made of a hygroscopic material such as sponge. The waste ink pack 65 can also be designed to have a capacity (size) capable of absorbing all the waste ink sucked during the life of the apparatus. As the paper feeding cassette 3, for example, one for loading the recording material 2 of A4 size is used, and the paper feeding cassette 3 is detachably attached to the lower part of the apparatus main body 1 as shown in FIG. There is.

Next, the operation of the image forming apparatus according to this embodiment will be described with reference to FIGS. When receiving an image recording command from a device such as a personal computer, the paper feed roller 4
Starts to rotate, and the uppermost one of the recording materials 2 stacked in the paper feed cassette 3 is separated by a separation claw (not shown),
The separated recording material 2 is sent out along the paper feed guide 5 and conveyed to a position where the leading end of the recording material 2 abuts on the registration roller pair 8.

In the registration roller pair 8, the skew feeding of the recording material 2 being conveyed is corrected by utilizing the nip portion thereof. Therefore, by rotating the rotary drum 10 while detecting the rotational position of the rotary drum 10 by a drum rotational position sensor (not shown), the recording material 2 fed from the front end of the paper feed guide 5 by the front gripper 14 is conveyed. The rotating drum 10 is set at a position where the can be gripped.

Then, the skew-corrected recording material 2 is conveyed by a registration roller 8 driven by a motor (not shown) by a predetermined movement amount along the paper feed guide 5, whereby the recording material 2 is recorded. The tip end of the material 2 is gripped by the tip gripper 14 of the rotary drum 10. After the recording material 2 is gripped by the tip gripper 14, the driving force of the registration roller 8 is released, and the recording material 2 is conveyed by the rotation of the rotary drum 10 in the direction of arrow b.

The recording material 2 conveyed is the rotary drum 10.
When passing between the charging roller 13 and the charging roller 13, an electric charge is applied to the rotating drum 10 so that it is adsorbed. Rotating drum 10
Is rotated in the direction of arrow b, and the rear end of the recording material 2 is disengaged from the paper feed guide 5, the rear end of the recording material 2 is separated from the front gripper 14 by a predetermined length (longitudinal length in the case of A4 size). It is gripped by a rear end gripper 15 provided at a position apart from each other in the direction dimension of 297 mm). As a result, the operation of winding the recording material 2 around the rotary drum 10 is completed.

During a series of paper feeding operations for winding the recording material 2 around the rotary drum 10, the recovery means (recovery system unit) 62 sucks or preliminarily ejects ink to the ink jet head 51. Recovery operation is performed. When the recovery operation is completed, the inkjet cartridge 50 is swung around the carriage rail 52 by the plunger 56, and the inkjet cartridge 50 is rotationally moved from the position shown by the solid line in FIG. 1 to the position shown by the broken line (recording operation position). .

That is, the ink jet head 51 capped by the cap 63 is separated from the cap 63 and the recording material 2 held on the rotary drum 10 is removed.
It is set at a position facing the upper recording position 72 and is set in a recording standby state.

When a recording operation start command is issued, the rotating drum 10 rotates with the recording material 2 in the direction of arrow b at a predetermined peripheral speed by a motor (not shown). By ejecting ink droplets toward the timing and the position, image recording with a constant width is performed.

When the ink jet head 51 completes recording of a certain width by one rotation of the rotary drum 10, the carriage motor 59 is rotated by a certain amount to scan and move the ink jet cartridge 50 together with the carriage 54 by a certain pitch. Carriage 5
4 and the ink jet cartridge 50 are moved to a position facing the unrecorded portion adjacent to the recorded portion on the recording material 2, and the next image recording with a constant width is performed. By repeating these operations, one image of the recording material 2 is recorded.

At this time, in the case of using a so-called on-demand type ink jet head in which ink droplets are selectively ejected, when the time interval of ink ejection becomes large, the viscosity of the ink near the ejection port 82 increases (increases). Sticky)
The discharge port 82 may be clogged. In order to prevent this clogging, a suction operation or a preliminary discharge operation for discharging ink from all the discharge ports is regularly performed.

Therefore, in this embodiment, as shown in FIG. 3, the recovery system unit 62 is integrally formed with the carriage 54 and scans (moves) in the same manner, so that one recording material 2 is recorded. Plunger 56
By simply rotating the inkjet head 51 from the recording position indicated by the chain double-dashed line to the recovery position that faces the cap 63, it is possible to easily perform ink discharge (suction operation or preliminary ejection operation) as a recovery operation at any time. .

Therefore, it becomes possible to periodically discharge the ink before the increase in the ink viscosity near the discharge port 82 reaches a limit, and in particular, the small droplet discharge that is easily affected by the viscosity increase due to the evaporation of the solvent in the ink. Even in the case of the ink jet head of the type, the recovery operation can be executed at any time without any trouble. In addition to this, it is possible to eliminate a wasteful time for returning the carriage 54 to the recording start position, and it is also possible to improve the throughput of the recording operation.

Further, since the waste ink pack 65 is arranged in the entire area where the recovery system unit 62 scans (moves), the ink discharged to the recovery system unit 62 (waste ink) is not recovered by the recovery system unit 62. Even at the position, the waste ink pack 65 can be dripped.

When the recording is completed, the carriage 54 is returned to the position shown in FIGS. 1 and 2 by the power transmitted from the carriage motor 59, and thereafter, the operation of the plunger 56 causes the ink jet cartridge 50 to be drawn in a solid line in FIG. As shown by, the ink jet head 51 has a cap 6
3 is rotated to a position facing 3.

At this time, the wiper blade 64 is fixed to the recovery system unit 6 as shown in FIG. 1 by a plunger (not shown).
It is set in a position protruding from 2, so
While the inkjet cartridge 50 is swung by the plunger 56, foreign substances such as ink and dust adhering to the ejection port surface 81 of the inkjet head 51 are wiped and removed (cleaning) by the wiper blade 64.
Is done.

A recovery system unit (recovery means) 62
Incorporates a pump for sucking the ink (waste ink) discharged into the cap 63 and the ink remaining in the discharge port 82 to recover the ink discharge function. Therefore, the ink sucked by this pump also recovers the recovery system unit 6
2 is discharged to the waste ink pack 65 arranged in the lower part of the entire scanning range.

After the recording is completed, the tip gripper 1
The leading end portion of the recording material 2 is lifted from the surface of the rotary drum 10 by 4 so that the recording material 2 is caught by the separation claw 16. Then, the recording material 2 has the separation claw 16
Is separated from the surface of the rotating drum 10 at
The sheet is conveyed along 0 and is ejected onto the sheet ejection tray 92 by the sheet ejection roller 91.

Next, the cleaning roller 17 contacts the rotating drum 10 at a position immediately after the recording material 2 on the rotating drum 10 is peeled from the rotating drum 10 by the separating claw 16. When the cleaning roller 17 comes into contact, foreign matter such as ink mist adhering to the surface of the rotary drum 10 is wiped off to clean the surface of the drum. By cleaning the drum surface, the next recording material 2
Of the recording material is prevented from being deteriorated, and the recording material to be adsorbed next is prevented from being soiled.

According to the first embodiment described with reference to FIGS. 1 to 4 above, the recovery operation of the ink jet head 51 can be performed within a short time even during recording, so that the recording time is further shortened. An image forming apparatus capable of improving throughput can be provided. Further, the recovery system unit (recovery means) 62 can be arranged at a position adjacent to the rotary drum 10 in the radial direction within the length range of the rotary drum 10, not at a position displaced in the axial direction of the rotary drum 10. An image forming apparatus can be realized.

Further, there is no extra operation (scanning) such as returning the ink jet head to the home position for the recovery operation, and the recovery operation can be executed without changing the axial position with respect to the rotary drum 10. The connection accuracy is improved, and it is possible to perform recording with higher accuracy.

FIG. 5 is a schematic perspective view showing a second embodiment of the image forming apparatus to which the present invention is applied. The vertical sectional view of this embodiment is the same as that of FIG. In addition, the first of FIGS.
Portions corresponding to the respective portions of the embodiment are denoted by the same reference numerals. The main difference between FIG. 2 and FIG. 5 is that in this embodiment, two sheet feeding cassettes 3a and 3b are detachably mounted,
The recording material 2a, 2b (a plurality of recording materials) can be simultaneously fed from each of these paper feed cassettes 3a, 3b.

In the first embodiment shown in FIG. 2, the recording material 2 of a predetermined size (for example, A4 size) is fed one by one, whereas in the second embodiment shown in FIG. The cassettes 3a and 3b are mounted side by side in the scanning direction of the carriage 54, and two recording materials 2a and 2b are attached to the rotary drum 10.
Is configured to be able to be simultaneously fed and discharged. The two recording materials 2a and 2b may have the same size or different sizes.

Along with this, the axial length of the rotary drum 10 of the second embodiment of FIG. 5 is longer than that of the first embodiment of FIG. 2, and is, for example, about 500 mm. . In addition, the carriage rail 52 and the auxiliary rail 55,
The lengths of the carriage belt 58, the waste ink pack 65, and the like are also increased in proportion to the increase in the length of the rotary drum 10. The structure around the carriage 54 and the recovery system unit 62 is substantially the same as that of the first embodiment shown in FIGS.

According to the configuration of the second embodiment of FIG. 5, when recording (outputting) images on a plurality of recording materials 2 in succession, two recording materials 2 are fed simultaneously. It is possible to reduce the time required for feeding and discharging per recording material by half by performing paper formation, continuous image formation (recording) on the rotary drum 10, and discharging two sheets at the same time. It becomes possible to shorten the total recording time.

Since the rotating drum 10 becomes longer in the axial direction, the moving distance of the carriage 54 also becomes longer, so that the number of recovery operations during one scan of the carriage 54 also increases. Therefore, compared with the conventional example in which the carriage is returned to the home position one by one to perform the recovery operation, the moving distance of the carriage 54 can be greatly reduced.
The recording time can be further shortened.

FIG. 6 is a schematic perspective view showing a third embodiment of the image forming apparatus to which the present invention is applied. The vertical sectional view of this embodiment is also the same as that of FIG. In addition, the first of FIGS.
Parts corresponding to those of the embodiment and the second embodiment of FIG. 5 are designated by the same reference numerals. The main difference between FIG. 2 and FIG. 6 is that
The sizes of the paper feed cassette 3 and the recording material 2 and the paper feed attitude are shown.

That is, in the first embodiment shown in FIG.
The 4 size recording material was fed in the vertical direction.
In the embodiment, the paper feed cassette 3 is enlarged for A3 size, and one A3 size recording material 2 is laterally fed. Along with this, the axial length of the rotary drum 10 is expanded to about 500 mm.

Further, the lengths of the carriage rail 52, the auxiliary rail 55, the carriage belt 58, the waste ink pack 65, etc. are increased by the increase in the axial length of the rotary drum 10. The configuration around the carriage 54 and the recovery means (recovery system unit) 62 of the third embodiment of FIG.
This is substantially the same as the case of the first embodiment of FIG. 3 and the second embodiment of FIG.

In the third embodiment shown in FIG. 6 as well, the paper feed cassette 3 is provided with a separation pawl (not shown), and the recording material 2 in the paper feed cassette 3 is maximally moved by the paper feed roller 4 and the separation pawl. One of the upper layers is separated. The separated recording material 2 is
It is fed toward the rotary drum 10 by the carrying force of the paper feed roller 4, and is mounted (held) on the surface of the rotary drum 10 by the same operation as in the first embodiment.

In FIG. 6, the axial length of the rotary drum 10 is about 500 mm, and the front gripper 14 and the rear end gripper 15 are about 50 mm parallel to the axial direction of the rotary drum 10.
It is provided over a length of 0 mm. In this way, one sheet of A3 size recording material 2 is placed in the horizontal position in the rotating drum 1
It is configured so that it can be held on the surface of zero.

According to the third embodiment of FIG. 6, it is possible to deal with the recording material 2 having a relatively large size (for example, A3 size), and the axial length of the rotary drum 10 is increased. Since the moving distance of the carriage 54 also increases,
Even though the number of recovery operations per scan of the carriage 54 increases, the moving distance of the carriage 54 is greatly reduced compared to the conventional example in which the carriage 54 returns (moves) to the home position one by one to perform the recovery operation. Can be
It is possible to significantly reduce the recording time.

In the above embodiment, the case where one ink jet head 51 is used has been illustrated, but the present invention uses a plurality of ink jet heads for recording a color image or a gradation image. When used, the same effect can be obtained and the same effect can be obtained.

As the recording means, in addition to the ink jet cartridge 50 in which the ink jet head 51 and the ink tank are integrated, the ink jet head and the ink tank are separately arranged, and the space between them is connected by an ink supply tube or the like. Can be freely adopted,
The present invention can be similarly applied regardless of the arrangement of the inkjet head and the ink tank.
A similar effect can be obtained.

Further, the present invention can be similarly applied to an image forming apparatus using an inkjet head using an electromechanical transducer such as a piezo element as long as it is an inkjet head. The present invention brings about an excellent effect in an image forming apparatus using an ink jet head of a system which discharges ink by utilizing the above. According to such a method, it is possible to achieve higher density and higher definition of recording.

Further, although the present invention employs a system in which the recording material is held by the rotating drum to perform recording, the same operation and effect can be obtained even if the recording material is held by the film-shaped endless belt. Can be achieved.

[0100]

As is apparent from the above description, according to the first aspect of the invention, in the image forming apparatus for forming an image on the recording material by the recording means, the rotating drum and the recording material on the rotating drum are provided. Holding means for holding, an inkjet head for forming an image by ejecting ink onto a recording material held on a rotary drum, a recovery means for recovering the function of the inkjet head, and an inkjet head in the axial direction of the rotary drum. A drive mechanism for scanning the head and the recovery means, a displacement mechanism for displacing the inkjet head to a position facing the recovery means, a paper feeding means for supplying a recording material to a rotary drum, and a recording target held on the rotary drum. Discharging means for discharging the material, and a control for controlling the displacement mechanism by operating the displacement mechanism after a lapse of a predetermined time during recording. Because a configuration having a means,,
The recovery operation of the inkjet head can be performed in a short time even during recording, there is no need to increase the device width for the recovery means, and the deterioration of the connection accuracy between the image bands due to the recovery operation is prevented. An image forming apparatus capable of performing the above is provided.

According to the second aspect of the invention, in the image forming apparatus for forming an image on the recording material by the recording means, the rotating drum, the holding means for holding a plurality of recording materials on the rotating drum, and the rotating drum. An inkjet head that ejects ink onto the recording material held above to form an image, a recovery unit that recovers the functions of the inkjet head, and a drive that scans the inkjet head and the recovery unit in the axial direction of the rotating drum. A mechanism, a displacement mechanism for displacing the inkjet head to a position facing the recovery means, a paper feeding means capable of simultaneously supplying a plurality of recording materials to the rotating drum, and a plurality of recording materials held on the rotating drum. At the same time, a discharging means capable of discharging and a displacement mechanism are operated after a lapse of a predetermined time during recording to perform a recovery operation of the inkjet head. Since it has a control means, the recovery operation of the inkjet head can be performed in a short time even during recording, and it is not necessary to increase the device width for the recovery means. Provided is an image forming apparatus capable of preventing a decrease in joining accuracy between bands and shortening a total recording time even when recording is performed on a plurality of recording materials.

According to the invention of claim 3, in addition to the structure of claim 1 or 2, the recovery means has an ink receiving portion for receiving the ink other than the recording ink ejected from the ink jet head. In addition to the effects described above, an image forming apparatus is provided that can shorten the total recording time even when an inkjet head that ejects minute ink droplets is used.

According to the invention of claim 4, the above-mentioned claim 1,
In addition to the configuration of 2 or 3, the recovery means is configured to have a cap means for covering the ejection port surface of the inkjet head. Therefore, in addition to the effects described above, capping is performed without moving the inkjet head in the scanning direction. An image forming apparatus is provided that can prevent the discharge port from drying.

According to the invention of claim 5, the above-mentioned claim 1,
In addition to the constitution of 2, 3 or 4, the cleaning member for cleaning the ejection opening face of the ink jet head is arranged between the position facing the recovery means and the recordable position. In addition to the above, there is provided an image forming apparatus capable of rapidly executing a cleaning operation for removing foreign matters such as ink and dust adhering to the ejection port surface of the inkjet head even during the recording operation.

According to the invention of claim 6, the above-mentioned claim 1,
In addition to the configuration of 2, 3, 4 or 5, the standby position of the inkjet head when the image forming apparatus is not operating is a position facing the recovery means. There is provided an image forming apparatus capable of further downsizing itself.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view of a first embodiment of an image forming apparatus to which the present invention is applied.

2 is a schematic perspective view showing a state at the start of recording of the image forming apparatus of FIG.

FIG. 3 is a schematic perspective view showing a state during recording of the image forming apparatus of FIG.

FIG. 4 is a partial perspective view schematically showing the structure of an ink ejection section of the inkjet head shown in FIG.

FIG. 5 is a schematic perspective view of a second embodiment of the image forming apparatus to which the invention is applied.

FIG. 6 is a schematic perspective view of a third embodiment of the image forming apparatus to which the invention is applied.

FIG. 7 is a schematic perspective view illustrating the configuration of a conventional serial type image forming apparatus.

FIG. 8 is a schematic perspective view illustrating the configuration of a conventional drum scan type image forming apparatus.

[Explanation of symbols]

 1 Device Main Body 2 Recording Material 3 Paper Feed Cassette 4 Paper Feed Roller 5 Paper Feed Guide 7 Cleaning Roller 8 Registration Roller 9 Conveyance Guide 10 Rotating Drum 13 Charging Roller 14 Tip Gripper 15 Rear Edge Gripper 16 Separation Claw 50 Inkjet Cartridge (Recording Unit) ) 51 inkjet head 52 carriage rail 54 carriage 55 auxiliary rail 56 plunger 58 carriage belt 59 carriage motor 62 recovery means (recovery system unit) 63 cap 64 wiper blade 65 waste ink pack 68 paper feed motor 72 recording position 81 ejection port surface 82 Discharge port 84 Liquid path 85 Electrothermal converter 90 Paper ejection guide 91 Paper ejection roller

Claims (8)

[Claims] 1. An image forming apparatus for forming an image on a recording material by recording means, comprising: a rotating drum; a holding means for holding the recording material on the rotating drum; and a recording material held on the rotating drum. An inkjet head that ejects ink to form an image, a recovery unit that recovers the functions of the inkjet head, a drive mechanism that scans the inkjet head and the recovery unit in the axial direction of the rotating drum, and a position that faces the recovery unit. A displacement mechanism for displacing the ink jet head, a paper feeding means for supplying the recording material to the rotating drum, a discharging means for discharging the recording material held on the rotating drum, and a displacement mechanism after a predetermined time has elapsed during recording. And a control unit that controls the operation of the inkjet head to perform a recovery operation of the inkjet head. 2. An image forming apparatus for forming an image on a recording material by recording means, a rotating drum, a holding means for holding a plurality of recording materials on the rotating drum, and a recording material held on the rotating drum. An inkjet head that ejects ink onto a material to form an image, a recovery unit that recovers the function of the inkjet head, a drive mechanism that scans the inkjet head and the recovery unit in the axial direction of the rotating drum, and a recovery unit that faces the recovery unit. A displacement mechanism for displacing the ink jet head to a position where the recording head is moved, a paper feed means capable of simultaneously supplying a plurality of recording materials to the rotating drum, and an ejecting means capable of simultaneously discharging a plurality of recording materials held on the rotating drum It has a control means for operating the displacement mechanism to perform the recovery operation of the inkjet head after a lapse of a predetermined time during recording. An image forming apparatus. 3. The image forming apparatus according to claim 1, wherein the recovery means has an ink receiving portion for receiving the ink other than the recording ink ejected from the ink jet head. 4. The image forming apparatus according to claim 1, 2 or 3, wherein the recovery means has a cap means for covering the ejection port surface of the inkjet head. 5. A cleaning member for cleaning the ejection port surface of the inkjet head is arranged between the position facing the recovery means and the recordable position. The image forming apparatus according to item 1. 6. The image forming apparatus according to claim 1, wherein the standby position of the ink jet head when the image forming apparatus is not operating is a position facing the recovery means. apparatus. 7. The ink jet recording means according to claim 1, wherein the recording means is an ink jet recording means provided with an electrothermal converter that generates thermal energy used for ejecting ink. The image forming apparatus according to item 5 or 6. 8. The image forming apparatus according to claim 7, wherein the recording unit ejects the ink from the ejection port by utilizing film boiling generated in the ink by the thermal energy generated by the electrothermal converter. .