JPH10324003A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet printer in which cleaning and capping can be carried out quickly and surely while reducing the size and enhancing the print quality. SOLUTION: A print head 200 can be moved in the axial direction intersecting a print face M1 and switched selectively among a cleaning position P3, a cap position P2 or a print position P1 on the axis. The print face M1 is an arcuate surface having the center on the rotational axis J1 and the print head 200 moves on a vertical axis J2 orthogonal to the rotational axis J1. The cleaning position P3, the cap position P2 and the print position P1 are set downward, in that order, on the vertical axis J2. The cap position P2 includes a perfect cap position P21 on the underside of the vertical axis J2 and a spit positron P22 on the upper side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer capable of performing color printing by jetting ink from a color ink jet nozzle of a print head onto a print medium.

[0002]

2. Description of the Related Art An ink jet printer prints characters, images, and the like by jetting (flying) ink from a fine ink jet nozzle equivalent to one dot. Clogging easily occurs. In particular, in an ink jet printer capable of color printing having ink jet nozzles for each color, the number of nozzles is larger than that for a single color ink jet printer, so that it is important to further prevent nozzle clogging and eliminate the clogging.

Therefore, in the ink jet printer, the ink jet nozzles are periodically cleaned, and when the printing is stopped, the ink jet nozzles are covered with a cap (that is, capped) to prevent ink drying.

[0004] As a cleaning method, a negative pressure suction method in which ink is suctioned from the tip of each nozzle using negative pressure, and ink is ejected by applying a higher pressure than usual to an ink pressure chamber common to each nozzle. There is a pressure discharge method,
A negative pressure suction system is often employed.

In the capping, a tip member (ejection port) of each nozzle is covered with a contact member (a porous ink absorbing member (sponge or the like)) provided in the cap. The capping is performed not only for the purpose of preventing the ink from drying as described above, but also when the ink is initially supplied to each nozzle.

A general ink jet printer uses a reciprocating moving means to form a print head which is integral with an ink tank (ink cassette) and has ink jet nozzles for one dot in a row direction and a plurality of dots in a column direction for a print medium. In addition, ink jet is performed while reciprocating over the entire length in the row direction, and characters, images, and the like are printed on the print surface of the print medium.

In such a serial type ink-jet printer, after printing is stopped, the print head is largely moved in the line direction of the print medium to an empty area outside the print area, and each nozzle of the print head is covered with a cap in the empty area. Shall be covered. Further, in order to eliminate ink clogging of each nozzle, the print head is moved to the above-mentioned empty area, and cleaning is performed using a cleaning unit.

By the way, the above-mentioned conventional print head is reciprocated over the entire length in the line direction, and printing is performed during each forward movement to print one line, and after printing one line, a print medium [plain paper, plastic film ( OHP film), etc.]. Compared to a so-called serial type ink jet printer in which M is fed one line in the column direction and repeats these steps, the printing speed can be greatly increased and continuous printing operation can be performed over many sheets. The present applicant has proposed an ink jet printer that can be made much smaller than a laser printer (for example, Japanese Patent Application No. 8-296957).

That is, in FIG. 8, the rotating body (drum 10) is rotatable in one direction about the rotation axis and can hold the print medium M on the outer peripheral surface 11 thereof. A nozzle unit (print head) 200 for each color is disposed in the rotation (Y) direction of the drum 10.

Therefore, an integrated nozzle unit 200 for each color in the entire length in the row direction (perpendicular to the paper surface) or an integrated nozzle unit 200 for each color in which a plurality of nozzle unit elements are arranged in the row direction, for example, between the inkjet nozzles Print medium M rotating while being reciprocated by the pitch
Ink can be printed in the row direction by spraying ink from the inkjet nozzles 207 for each color, and can be printed in the column direction while utilizing the rotation of the drum 10 during forward movement of the pitch between the inkjet nozzles. That is, since the row-direction printing and the column-direction printing can proceed at the same time, the printing speed can be significantly increased.

Further, since the nozzle unit 200 for each color and the ink tank (ink cassette) 213 for each color are arranged at a distance from each other via a tube, the nozzle unit 200 for each color can be lightened and reciprocated in the row direction. The fact that the moving speed can be greatly increased also contributes to further increase in printing speed, and ink tanks (ink cassettes) 2 for each color.
13 can be greatly expanded, so that, for example, a continuous printing operation of 500 sheets or more can be performed.

In order to realize these, one side (right side in FIG. 8) of the drum 10 is provided with a feeding means 60 and a medium feeding means 9.
0, and on the other side (left side in FIG. 8), the medium peeling means 140, the medium discharge / conveyance means 160, and the direction switching means 190
Are provided.

The feeding means 60 can selectively feed the printing medium M one by one from either the cassette feeding means 71 or the manual feeding means 61. The medium supply means 90 feeds the fed print medium M to the drum 1 at a predetermined timing.
Feed to the 0 side. The medium peeling means 140 peels the print medium M from the drum 10 after printing, and
0 discharges and conveys the peeled print medium M leftward in FIG. The direction switching unit 190 selectively switches between the discharge tray 192 and the upper discharge tray 193.

Thus, since the feeding, supply, holding, printing, peeling, and discharging and conveying of the print medium M can be continuously performed, multicolor printing of, for example, 20 or more sheets of A4 size can be performed in one minute.

[0015]

In such an ink jet printer of the prior proposal, the print head (200) is moved to an empty area in the row direction similarly to the above-mentioned general ink jet printer (serial type ink jet printer). When the cleaning and the capping are performed, a large space must be secured as the empty area in a row direction corresponding to a long print head, and the printer becomes large.

Further, the print head (200) must be largely moved in the row direction, and it takes a long time to prepare for cleaning and capping, and to return to the printing position after cleaning or the like. This is an obstacle to achieving the goal.

Further, the positioning accuracy of the print head with respect to the printing surface is apt to decrease, and it is difficult to achieve high quality printing.

[0018] The above-mentioned inconvenience also occurs in a conventional line type ink jet printer having a long print head in the row direction. Further, even in a serial type ink jet printer, a similar problem occurs when, for example, an attempt is made to shorten the reciprocating movement time (shortening the printing time) by increasing the dimension of the print head in the row direction. .

An object of the present invention is to provide an ink jet printer capable of performing cleaning and capping quickly and reliably while achieving downsizing and high quality printing.

[0020]

According to the first aspect of the present invention, a print head having ink jet nozzles for each color is mounted so as to be reciprocally movable in a direction of an axis crossing a print surface movable in one direction, and a print head. Is an ink jet printer formed so as to be selectively switchable between a cleaning position for cleaning each ink jet nozzle on the axis, a cap position for capping each ink jet nozzle, and a printing position for printing on a printing surface. is there.

In the case of this invention, the print head can be moved from the printing position in the direction of the axis crossing the printing surface and positioned at the cleaning position and the capping position, and the ink jet nozzles for each color can be cleaned and capped.

Here, the moving direction of the print head is
It is different from the row direction and column direction of the print medium,
Moreover, the moving distance from the printing position can be greatly reduced. Therefore, it is not necessary to secure a large empty space for cleaning and capping in the row direction (width direction) of the printing surface, and the relative positioning between the print head and the printing surface when returning to the printing position can be performed accurately. As a result, the inkjet nozzles for each color of the print head can be quickly and reliably cleaned and capped while achieving downsizing and high quality printing.

According to a second aspect of the present invention, there is provided an ink jet printer, wherein the printing surface is an arc surface centered on a rotation axis, and an axis crossing the printing surface is a vertical axis orthogonal to the rotation axis.

In the case of this invention, since the printing surface is an arc surface centering on the rotation axis, the printing surface is rotated and conveyed about the rotation axis, so that the printing surface is more quickly and accurately than the conventional linear movement. Can be fed in the column direction. Further, since the reciprocating movement direction of the print head is a vertical axis orthogonal to the arc-shaped printing surface, it is possible to save space in the horizontal direction.

Further, the print head is moved to the cleaning position,
It can be moved between the cap position and the printing position by the shortest distance. Furthermore, when the inkjet nozzles for each color are arranged close to each other to reduce the installation space,
Even if ink oozes from the nozzle tip during capping, it falls vertically downward and does not adhere to other nozzle tips. Therefore, color mixing is prevented.

According to a third aspect of the present invention, there is provided an ink jet printer in which the cleaning position, the cap position, and the printing position are arranged in this order from above to below the vertical axis.

According to this invention, the time required for moving the print head from the printing position to the cap position for capping after the printing is stopped and for moving the printing head from the cap position to the printing position to start printing are minimized. can do. Although the cleaning position is longer than the cap position from the printing position, cleaning is not always performed when printing is stopped or before printing is started, but is usually performed after a certain period of time. Therefore, there is no problem even if the movement time of the print head is slightly longer than that in the case of capping.

Therefore, in addition to the same operation and effect as in the first embodiment, the print head can be more quickly positioned at the frequently selected print position and cap position.

According to a fourth aspect of the present invention, there is provided the ink jet printer, wherein the cap positions are two close positions: a complete cap position below the vertical axis and a spit position above the vertical axis.

In the case of this invention, the tip of each ink jet nozzle is covered with the non-ink absorber of the cap by positioning the print head at the complete cap position at the time of initial ink supply or the like. Accordingly, it is possible to prevent ink leakage from nozzles at the time of initial ink supply, that is, wasteful consumption of ink. Here, the complete cap position is a position at which the tip (ejection port) of each ink jet nozzle of the print head comes into contact with a contact member in the cap and is closed.

When capping for a long time,
With the print head in the spit position, ink is ejected from each ink jet nozzle into the cap (that is, spit).

As described above, since the spits are formed with the tip of each nozzle and the contact member of the cap slightly separated from each other, the ink can be smoothly filled in the cap. Therefore, in addition to having the same operation and effect as the case of the third aspect of the present invention, it is possible to more reliably maintain the ink saturated water vapor pressure in the cap and to more effectively prevent ink drying. Since the spit position is close to the complete cap position, the distance between each nozzle tip and the abutting member in the cap is very small, and the ink ejected from each nozzle tip is surely capped by the cap. Can receive.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is applied to an ink jet printer having the same configuration as the previously proposed ink jet printer shown in FIG. 8, and as shown in FIGS. 1 to 7, a print head having an ink jet nozzle 207 for each color (a nozzle unit 200 for each color). Is moved in the direction of the axis crossing the printing surface M1 of the print medium M which can be moved in one direction, and is formed so as to be selectively switched to the cleaning position P3, the cap position P2, and the printing position P1 on the axis. I have.

In this embodiment, the "print surface M1 movable in one direction" is an arc surface centered on a rotation axis J1 of a rotating body (drum 10) described later. Also,
The axis crossing the printing surface M1 is a vertical axis J2 orthogonal to the rotation axis J1.

Note that the same components as those of the previously proposed ink jet printer (FIG. 8) are denoted by the same reference numerals, and description thereof will be simplified or omitted.

As shown in FIG. 1, the print head (200) has ink jet nozzles 207 for each color.
The head support member 210 is formed so as to be able to reciprocate in the direction of the vertical axis J2 and to be selectively positioned at the cleaning position P3, the cap position P2, and the printing position P1.

Here, the printing position P1 is defined as the printing surface M1 of the printing medium M by jetting ink downward from the ink jet nozzles 207 for each color of the printing head (200).
This is the position where printing is possible. The printing position P1 is set such that, for example, the distance between the tip of each nozzle 207 and the drum outer peripheral surface 11 is 0.
It is selected to be 5 to 1 mm.

The cap position P2 is defined as the print head (20
0) and a cap 10 between the drum 10 and the cap means 220 can be selected, and the ink jet nozzle 207 for each color of the print head (200) can be covered with the cap 221 in the interposed state. It is a height position.

The cap means 220 is, as shown in FIG.
It includes a cap 221 and a cap moving means 225, and is formed so that the tip of each color inkjet nozzle 207 can be capped. As shown in FIG. 5, the cap 221 includes a seal frame member 222 that surrounds and seals the tip (ejection port) of each nozzle 207, and a seal frame member 222.
And a contact member (223) provided so as to be able to contact the tip of the nozzle 207 for each color. The contact member is
It is formed from the non-ink absorber 223.

The cap moving means 225 comprises a pair of guide rods (227, 227) extending in the left-right direction in FIG.
And a cap support member 226 whose both ends are movably supported by the respective guide rods 227.
21 is formed between the print head (200) and the drum 10 at a raised position from the horizontal direction (the left-right direction in FIG. 2) and is capable of entering and retracting.

In this embodiment, as shown in FIGS. 6A and 6B, the cap position P2 is set to the vertical axis J2.
Are located close to each other, ie, a complete cap position P21 on the lower side and a spit position P22 on the upper side. The complete cap position P21 is a position where the tip of each color inkjet nozzle 207 comes into contact with the non-ink absorber 223 in the cap 221 as shown in FIG. The spit position P22 is a position for spitting ink in the cap 221 with the tip of each nozzle 207 and the non-ink absorber 223 slightly separated from each other, as shown in FIG.

Further, the cap position P2 is set so that the cap means 220 cannot interfere with the externally projecting auxiliary means (for example, a claw for holding the leading end of the print medium M) among the auxiliary means mounted on the drum 10. Print head (20
0).

Next, as shown in FIG. 1, the cleaning position P2 is defined as a position where the cleaning means 230 can select between intervening and non-intervening between the print head (200) and the drum 10 and in the interposed state. ), The cleaning means 2 is connected to the inkjet nozzle 207 for each color.
Reference numeral 30 denotes the height position of the print head (200) that can be cleaned.

As shown in FIGS. 3 and 4, the cleaning means 230 includes a suction tool 231 and a suction tool moving means capable of moving the suction tool 231 in the row direction of the printing surface M1 (in the direction perpendicular to the sheet of FIG. 2). 235, and the nozzles 207 are formed so that they can be cleaned while moving in the row direction and sucking ink from the ink jet nozzles 207 for each color during non-printing.

The suction tool 231 includes a main body 231D, and a plurality of ink suction nozzles 231N radially arranged on the main body 231D in correspondence with the respective ink jet nozzles 207 of the nozzle units 200 for each color. . Each ink suction nozzle 231N has a pipe 232
Through the negative pressure generating means 233 (the waste ink storage tank 23).
3T, a suction pump 233P) is connected.

Therefore, each ink suction nozzle 231
When the suction pump 233P is driven in a state where N is aligned with the tip of each ink jet nozzle 207, the ink in each ink jet nozzle 207 is discharged to the waste ink storage tank 233.
Collected in T. The suction device 231 has a wiper 2 that can wipe ink attached to the tip of each inkjet nozzle 207 while being in contact with the tip immediately after cleaning.
34 are provided.

The suction tool moving means 235 is shown in FIGS.
As shown in FIG. 7, a pair of guide members (guide rods 235G and guide bars 235B) arranged in parallel with the rotation axis J1 of the drum 10 have a suction tool support member 235S whose both ends are movably supported. The suction tool 231 attached to the member 235S is moved in the row direction (X direction) of the printing surface M1.
The ink suction nozzle 231N is formed so as to be able to face the tip of the ink jet nozzle 207 for each color in a non-contact state.

Next, the operation of this embodiment will be described. The print head (200) can be moved from the print position P1 in the direction of the vertical axis J2 to the cleaning position P3 and the capping position P2 to clean and cap the inkjet nozzles 207 for each color.

Here, since the print head (200) is moved in the direction of the vertical axis J2, it can be moved between the cleaning position P3, the cap position P2 and the printing position P1 by the shortest distance.

Further, since the cleaning position P3, the cap position P2, and the printing position P1 are set in this order from above to below the vertical axis J1, the print head (200) is moved from the printing position P1 after printing is stopped. It is possible to minimize the moving time of the print head (200) when moving to the cap position P2 and performing capping, or conversely, when moving from the cap position P2 to the printing position P1 and starting printing.

The cleaning position P3 has a longer distance from the printing position P1 than the cap position P2. However, cleaning is not always performed when printing is stopped or before printing is started. Therefore, even if the moving time of the print head (200) is slightly longer than that in the case of capping, no problem occurs.

For example, in the case of capping, the print head (200) is moved up along the vertical axis J2 and positioned higher than the cap position P2. Next, the cap moving means 225 is driven to move the cap 221 to the position shown in FIG.
To horizontally move rightward from the retracted position indicated by the two-dot chain line and position vertically below the print head (200).

Next, in that state, the print head (200)
Is lowered to the cap position P2 (spit position P22).
, The tip of each color inkjet nozzle 207 is surrounded by the cap 221. This prevents ink drying.

When capping is performed for a long time, ink is ejected from each ink jet nozzle 207 into the cap 221 in the state of the spit position P22 (that is, spit).

At this time, the tip of each nozzle 207 and the cap 2
Since the spit is spit in a state where it is slightly separated from the non-ink absorber 233 in the ink 21, the ink is smoothly filled in the cap 221, and the ink saturated steam pressure is maintained, so that the ink drying can be more effectively prevented.

Since the spit position P22 is close to the complete cap position P21, the distance between the tip of each nozzle 207 and the non-ink absorber 233 of the cap 221 is very small. The ejected ink can be reliably received by the cap 221.

Further, by lowering the print head (200) from the spit position P22 and positioning the print head (200) at the complete cap position P21 at the time of initial ink supply or the like, the tip of the ink jet nozzle 207 for each color is moved to the non-ink absorber 233 of the cap 221. Covered with. Accordingly, it is possible to prevent ink leakage from the nozzle 207 at the time of initial ink supply, that is, waste of ink.

In the case of cleaning, the print head (200) is raised and positioned at the cleaning position P3. Next, the suction tool moving means 235 is driven to horizontally move the suction tool 231 so that each ink jet printer absorption nozzle 231N is aligned with the end of each color ink jet nozzle 207 of the print head (200). Position.

Next, in this state, the suction tool moving means 235 is driven while driving the suction pump 233P, and the suction tool 23
1 is horizontally moved in the row direction of the printing surface M1. This makes it possible to individually suction the ink from the ink jet nozzles 207 for each color that are sequentially opposed by the ink suction nozzles 231N of the suction tool 231 to clean the nozzles 207. At the same time, the ink attached to the tip of each nozzle 207 can be wiped by the wiper 234.

According to this embodiment, the print head (200) is moved in the direction of the axis crossing the printing surface M1, and selectively switched to the cleaning position P3, the cap position P2, and the printing position P1 on the axis. Since it is formed so as to be possible, cleaning and capping can be performed with the moving distance from the printing position P1 greatly reduced.
Further, the print head (2) returned to the print position P1
00) and the printing surface M1 can also be accurately positioned.
Accordingly, the ink jet nozzles 207 for each color of the print head (200) can be reduced while achieving miniaturization and high quality printing.
Can be quickly and reliably cleaned and capped.

Since the printing surface M1 is an arc surface centered on the rotation axis J1 and the axis of movement of the print head (200) is the vertical axis J1 orthogonal to the rotation axis J1, the printing surface M1 is By rotating, it is possible to quickly and accurately feed in the column direction. The print head (2
00) can be moved by the shortest distance between the cleaning position P3, the cap position P2, and the printing position P1. Further, color mixing during capping is prevented.

Further, since the cleaning position P3, the cap position P2, and the printing position P1 are respectively set in this order from the upper side to the lower side of the vertical axis J1, the printing position P1 and the cap position P2 which are frequently selected are set. The print head (200) can be positioned more quickly.

Further, the cap position P2 is set to the vertical axis J2.
Are located close to each other, ie, a full cap position P21 on the lower side and a spit position P22 on the upper side. Therefore, when capping is to be performed for a long time, ink from each of the ink jet nozzles 207 is kept in the cap 221 in the spit position P22. You can spit in. Therefore,
The ink saturated water vapor pressure in the cap 221 can be more reliably maintained, and ink drying can be more effectively prevented.

[0064]

According to the first aspect of the present invention, the print head is moved in the direction of the axis crossing the printing surface, and is selectively switchable between the cleaning position, the cap position, and the printing position on the axis. Therefore, cleaning and capping can be performed with the moving distance from the printing position greatly reduced. Further, when the print head is returned to the print position, the relative positioning between the print head and the print surface can be accurately performed. Therefore, the inkjet nozzles for each color of the print head can be quickly and reliably cleaned and capped while achieving downsizing and high quality printing.

According to the second aspect of the present invention, the printing surface is an arc surface centered on the rotation axis and the axis along which the print head moves is a vertical axis orthogonal to the rotation axis.
In addition to the same effects as in the case of the first aspect of the present invention, the printing surface can be fed quickly and accurately by rotating and transporting the printing surface, and the printing speed can be further increased. In addition, the print head can be moved between the cleaning position, the cap position, and the printing position with the shortest distance, and preparation for cleaning or the like and return to the printing position can be performed more quickly. Further, color mixing during capping is prevented.

According to the third aspect of the present invention, since the cleaning position, the cap position, and the printing position are in this order from the upper side to the lower side of the vertical axis, the moving stroke of the print head is minimized. Can be. Therefore, in addition to the same effect as the case of the invention described in claim 2, the print head can be more quickly positioned at the frequently selected printing position and cap position.

According to the fourth aspect of the present invention, since the cap position is set to two close positions of the complete cap position on the lower side of the vertical axis and the spit position on the upper side, when capping is performed for a long time, Ink can be spit into the cap from each ink jet nozzle in the state of the spit position. Therefore, the same effect as in the case of the third aspect of the invention can be obtained, and the ink saturated water vapor pressure in the cap can be more reliably maintained to prevent ink drying more effectively.

[Brief description of the drawings]

FIG. 1 is a diagram for describing an embodiment of the present invention.

FIG. 2 is a view for explaining an interposed state between a cap unit and a cleaning unit.

FIG. 3 is an exploded perspective view for explaining a cleaning unit.

FIG. 4 is a view for explaining a positional relationship between a cleaning unit and an inkjet nozzle for each color.

FIG. 5 is a perspective view for explaining the cap means.

FIG. 6 is a view for explaining the positional relationship between the cap means and the inkjet nozzles for each color.

FIG. 7 is a diagram for explaining the overall configuration.

FIG. 8 is a diagram for explaining a previously proposed ink jet printer.

[Explanation of symbols]

 Reference Signs List 10 drum (rotating body) 11 outer peripheral surface 200 nozzle unit for each color (print head) 207 inkjet nozzle for each color 210 head support member 220 cap means 221 cap 223 non-ink absorber (contact member) 230 cleaning means 231 suction tool 234 wiper 235 Suction tool moving means P1 Printing position P2 Cap position P21 Complete cap position P22 Spit position

Claims (4)

[Claims] 1. A print head having an ink jet nozzle for each color is mounted so as to be reciprocally movable in the direction of an axis crossing a print surface movable in one direction, and the print head cleans each ink jet nozzle on the axis. Printer that can be selectively switched between a cleaning position for printing, a cap position for capping each inkjet nozzle, and a printing position for printing on a printing surface. 2. The ink jet printer according to claim 1, wherein the printing surface is an arc surface centered on a rotation axis, and an axis crossing the printing surface is a vertical axis orthogonal to the rotation axis. 3. The ink jet printer according to claim 2, wherein the cleaning position, the cap position, and the printing position are arranged in this order from above to below the vertical axis. 4. The ink jet printer according to claim 3, wherein the cap positions are two close positions of a complete cap position below the vertical axis and a spit position above the vertical axis.