JP2002211059A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recorder capable of achieving high quality of an image by preventing a recording medium from being floated even when a length of a nozzle is increased. SOLUTION: A serial scan type ink jet recorder performs recording by allowing an ink jet head 20 to scan. The ink jet recorder comprises one or more ink jet heads 20 each having a plurality of ejection nozzles arranged in a sub-scanning direction, a recording medium supporting means provided to a position opposite to the plurality of nozzles, and one or more intermediate spurs (recording medium pressing means) 100 which are provided to a portion opposite to the recording medium supporting means between the nozzle positioned at the uppermost upstream side and the nozzle positioned at the lowermost downstream side in the sub-scanning direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a serial scan type ink jet recording apparatus which performs recording by scanning with an ink jet head.

[0002]

2. Description of the Related Art Conventionally, a serial scan type recording apparatus which performs recording by scanning with an ink jet head has been known, and the nozzle configuration has been complicated along with the colorization of recording.

[0003] There are roughly two types of nozzle configurations in color printing. The first type is a so-called vertical nozzle type in which nozzle rows for ejecting inks of different colors are vertically arranged in the sub-scanning direction. The second is a row of nozzle rows for ejecting inks of different colors arranged in parallel in the main scanning direction. It is a side-by-side nozzle type arranged.

On the other hand, recent serial scan type recording apparatuses have the following tendency.

1) High-speed printing 2) High-quality color printing 1) High-speed printing includes data processing speed, paper feeding speed,
Along with the paper feed speed, there is a remarkable tendency to increase the number of nozzles due to advances in inkjet head manufacturing technology. Vertical nozzles,
The number of nozzles in the horizontally arranged nozzles is increased, and 600 nozzles are arranged at a pitch of 1/600 inch, and a head having a nozzle row with a total length of about 25 mm is being put into practical use.

[0006] Regarding 2) the high quality of color recording,
There is a tendency to obtain high-definition images with nozzles that eject smaller ink droplets. In order to increase the image quality by reducing the size of the ink droplet, the landing accuracy of the ink droplet is also required. Since it is inevitable that the ink ejected from the head flies obliquely within a certain range, it is desirable that the distance from the orifice surface of the inkjet head to the recording medium surface be as short as possible.

Therefore, in order to achieve both high speed and high image quality, it is necessary to provide a technique for maintaining a constant distance from the orifice surface to the surface of the recording medium over a long nozzle array.

[0008]

However, the above-mentioned prior art has the following disadvantages.

That is, since the means for pressing the recording medium against the platen includes only the pinch roller on the upstream side of the nozzle and the spur on the downstream side, if the nozzle length becomes longer, the interval between them becomes wider. For this reason, particularly when performing photographic recording with a large amount of ink applied, the recording medium absorbs water and expands, and the recording medium between the two rises upward from the platen. If the lifting becomes remarkable, the orifice surface of the head and the recording medium rub against each other, and the image quality deteriorates, or in the worst case, the recording medium is broken.

In order to prevent the above problem, the distance between the orifice surface and the recording medium may be increased to such an extent that the recording medium is not rubbed even if it is lifted up. .

There is also a method of using a recording medium that does not undulate even when absorbing water, but such a medium is generally expensive,
Due to limited media, this is not a desirable solution.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet recording apparatus capable of suppressing a floating of a recording medium and securing high image quality even when a nozzle length is long. To provide.

[0013]

According to a first aspect of the present invention, there is provided a serial scan type ink jet recording apparatus which performs recording by scanning with an ink jet head. A single or a plurality of inkjet heads having discharge nozzles, recording medium support means provided at a position facing the plurality of nozzles, and a plurality of discharge nozzles facing the recording medium support means, and One or more recording medium holding means provided at a position in the sub-scanning direction between the nozzle located at the most upstream position and the nozzle located at the most downstream position are provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the recording medium pressing means is constituted by a roller or a spur which rotates following the conveyance of the recording medium.

According to a third aspect of the present invention, in the first or second aspect of the present invention, there is provided one or more inkjet heads having a plurality of nozzle rows for ejecting different types of inks displaced in the sub-scanning direction; It is characterized in that a recording medium pressing means located at a boundary between the plurality of nozzle rows is provided.

According to a fourth aspect of the present invention, in the third aspect of the present invention, no discharge nozzle is provided at a boundary between the nozzle rows.

According to a fifth aspect of the present invention, in the first or second aspect of the invention, there is provided one or more ink jet heads having a plurality of nozzle rows for discharging different types of inks arranged in parallel in the main scanning direction; It is characterized in that a recording medium pressing means located within the range of the nozzle row in the sub-scanning direction is provided.

According to a sixth aspect of the present invention, there is provided the ink jet head according to any one of the first to fifth aspects, wherein the ink jet head has a relief portion at a portion facing the position in the sub-scanning direction where the recording medium pressing means exists. It is characterized by having.

[0019]

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

<First Embodiment> FIG. 1 is an overall perspective view of an ink jet recording apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a chassis, which is a structure for supporting other components. Body. Reference numeral 2 denotes an auto sheet feeder (hereinafter abbreviated as ASF), which picks up sheets 3 one by one from a bundle of recording sheets 3 loaded therein by a sheet feed roller and a sheet separating mechanism (not shown).
The sheet is fed to an LF roller 6 described later. Then, the paper 3 is stacked against the left end reference 4, and the paper 3 is positioned against the right end of the side guide 5 that can slide left and right according to its size.

The picked up paper 3 is an LE roller 6
To the contact point of the pinch roller 7. Here, the surface of the LF roller 6 is processed by a coating process so as to have a predetermined friction coefficient. The rubber pinch roller 7 is rotatably supported by a pinch roller guide 8 at both ends thereof.
The pinch roller guide 8 is rotatable about a rotation shaft 9 and is urged by a spring (not shown) in a direction to press the pinch roller 7 against the LF roller 6.

Paper 3 picked up by paper feed roller
After the leading end reaches the stationary LF roller 6, the paper is further fed by a feed roller by several mm. In this process, the paper 3 bends to form a loop, and so-called registration is performed to secure the parallelism between the leading end of the paper 3 and the axis of the LF roller 6 by the stiffness of the paper.

When the registration is completed, the LF roller 6 rotates, and the sheet 3 is fed between the LF roller 6 and the pinch roller 7 while being fed by a predetermined amount, and stops at the recording standby position.

An LF gear 10 is press-fitted into the left end of the LF roller 6 via the chassis 1, and the LF gear 10 has an LF pulley 11 formed coaxially and integrally therewith.

An LF belt 12 is hung on the LF pulley 11, and a driving force is transmitted to a discharge pulley 13 on the downstream side. The LF gear 10 forms a gear train with the LF motor gear 14, and a driving force is transmitted from the LF motor 15.

Reference numeral 16 denotes a platen, and the sheet 3 sandwiched between the LF roller 6 and the pinch roller 7 passes through the surface of the platen 16. Reference numeral 17 denotes a discharge roller, which is fixed to the discharge pulley 13 and is driven to rotate by the LF motor 15. The paper discharge roller 17 is provided with eleven rubber portions 18, and a spur 19 is pressed against each of the rubber portions 18 by a biasing means (not shown).

Reference numeral 100 denotes an intermediate spur which is a feature of the present invention. The size of the intermediate spur 100 is 1/2 of the spur 19 and its diameter is 4 mm. The 11 intermediate spurs 100 are provided along the 11 ribs 101 provided on the surface of the platen 16, and are pressed against the ribs 101 by a biasing means (not shown), like the spur 19.

FIG. 2 is a cross-sectional view of the sheet feeding section. The sheet 3 sandwiched between the LF roller 6 and the pinch roller 7 is sandwiched between eleven ribs 101 and an intermediate spur 100, and
8 and spur 19 are sent. The spur 19 and the intermediate spur 100 are formed in a star shape.
And the ribs 101 are in point contact with each other, so that the image is not rubbed even when the recorded paper 3 is nipped. An escape portion 107 for the intermediate spur 100 is provided in a bubble jet (registered trademark) head 20 described later, and the head orifice surface 10
The distance between the sheet 8 and the sheet 3 is set to 1.5 mm.

Reference numeral 20 denotes a bubble jet head. In the bubble jet head 20, ink tanks 24 to 27 corresponding to respective colors of black, cyan, magenta, and yellow can be attached and detached, and the ink becomes empty. Each can be replaced separately. In consideration of the frequency of use, the black tank 24 is provided with other tanks 25, 26, 27.
The capacity is larger than that of.

The bubble jet head 20 includes the carriage 2
9 and positioned and fixed. Carriage 29
Inside, an electrode portion 30 for transmitting a signal from the main body to the bubble jet head 20 is provided for each of black and color. When the bubble jet head 20 is set on the carriage 29, the electrode section 30 is pressed against a head-side electrode (not shown) provided on the bubble jet head 20 to obtain conduction. Some of these electrodes include head 2
There is also an electrode for determining whether 0 is set. That is, the presence or absence of the head 20 can be determined by reading the resistance value between the two electrodes.
Reference numerals 45 and 46 are reference surfaces for positioning the head 20.

Next, the nozzle configuration of the bubble jet head 20 will be described with reference to FIG.

FIG. 3 is a view of the head 20 viewed from the orifice surface side. In FIG. 3, reference numeral 102 denotes a black nozzle array for discharging black ink,
Nozzles are arranged at a pitch of 1/600 inch.

Numerals 103 to 105 denote nozzle rows corresponding to the respective colors of cyan, magenta and yellow.
Each nozzle is provided. No nozzle area 10 between cyan and magenta and between magenta and yellow
6,108 exist to prevent ink mixing between the nozzles. The length of this nozzle absent area is also set to 120/600 inches. That is, the black nozzle row 102, the cyan nozzle row 103, and the magenta nozzle row 104 are arranged in parallel. Reference numeral 107 denotes an escape for the intermediate spur 100, which is located so as to overlap the nozzle-free area 106.

The carriage 29 and the main board 32 fixed to the rear surface of the chassis 1
1 and the electrode section 30 is provided at the end of the flexible cable 31.

Reference numeral 33 denotes a carriage shaft which penetrates a bearing portion 34 of the carriage 29, and both ends of which are supported by the chassis 1. Reference numeral 35 denotes a carriage rail, and a slider (not shown) provided downstream of the carriage 29 can slide on the upper surface of the rail 35. Both ends of the carriage rail 35 are also supported by the chassis 1.

The carriage 29 includes a carriage shaft 3
3 and guided by the carriage rail 35,
With the bubble jet head 20, 28 or 60 mounted thereon, scanning can be performed in a direction perpendicular to the paper feed direction. A carriage belt 36 is joined to the carriage 29, and the belt 36 is stretched around a pulley of a carriage motor 37 and an idler pulley 38. When the carriage motor 37 is driven, the carriage 29 moves right and left. In the scanning state, the distance between the orifice surface of the nozzle and the surface of the paper 3 is kept at 1.5 mm.

Next, the recording operation of the ink jet recording apparatus will be described with reference to the flowchart of FIG.

When the power is turned on (STEP 1), the presence or absence of the head 20 is determined by the electrode unit 30 (STE 1).
P2) If there is no head 20, the user is notified by a buzzer or the like, and the carriage 29 is moved to the middle replacement position to urge the head 20 to be set. If the head 20 is present, the apparatus enters a standby state as it is (STEP
3).

Thereafter, when a recording signal is input (STE
P4) As described above, the paper 3 reaches the recording standby position, the carriage 29 scans, and one line of recording is performed (STEP 5). Then, if there is more data (STEP 6), if only black recording is to be performed, the paper 3 is fed by 360 nozzles, and the carriage 29 is reversed to perform recording of the second row (STEP 7). 12 for color recording
The paper 3 is fed by 0 nozzles, and the second row is similarly recorded.
Thereafter, carriage scanning and paper feeding are repeated until the image signal is completed, and when completed, the paper 3 is discharged to a paper discharge tray (not shown) (STEP 8).

In the present embodiment, the total length of the nozzle row is 1 inch (25.4 mm), and the distance between the LF roller 6 and the paper discharge roller 17 is about 60 mm.

Thus, the paper 3 from which the ink has been ejected tends to expand due to the moisture in the ink penetrating into the pulp fibers and to rise from the surface of the platen 16. In particular, this tendency becomes remarkable when a large amount of ink is applied to an image or the like. When the distance between the LF roller 6 and the paper discharge roller 17 increases as in this embodiment, the expanded paper 3
When the sheet 3 is remarkably lifted in the middle of the platen 16, the orifice surface 108 of the head 20 rubs against the sheet 3, causing an image failure or a paper jam. If an attempt is made to reduce the distance between the sheet 3 and the orifice surface 108 in order to realize high image quality, the adverse effect will increase more and more.

Therefore, in the present embodiment, the intermediate spur 10
0, and the escape 107 is further provided.
Is prevented by the intermediate spur 100 and the distance between the sheet 3 and the orifice surface 108 is reduced.

Second Embodiment Next, a second embodiment of the present invention will be described.

FIG. 5 is a view of the nozzle configuration of the bubble jet head 114 according to the present embodiment, as viewed from the orifice surface side.

This embodiment differs from the first embodiment only in the nozzle configuration. In FIG.
Reference numeral 2 denotes nozzle arrays for black, cyan, magenta, and yellow inks, respectively. Unlike the first embodiment, cyan, magenta, and yellow nozzle rows are arranged in parallel.

Reference numeral 113 denotes a relief portion similar to that of the first embodiment, and there is no nozzle in this portion. This escape part 11
300 pieces at 1/600 inch pitch on one side across 3
A total of 600 nozzles of each color are arranged on both sides.

The apparatus according to the present embodiment employs a system in which sheet feeding is performed 300 nozzles at a time, and printing for one line is completed by overlapping 300 nozzles on one side twice. By arranging the nozzles in parallel, the color can be superimposed by one carriage scan without arranging many nozzle rows in the sub-scanning direction, so that an apparatus having a high printing speed can be realized.

<Third Embodiment> Next, a third embodiment of the present invention will be described.

In the first embodiment, the escape portion 107 is provided in one head and the intermediate spur 100 is provided. However, it is also possible to arrange the two heads in tandem in the sub-scanning direction. FIG. 6 is a sectional view showing this example, in which two identical heads 120 and 121 are arranged in tandem. The nozzle configuration is the same as that of the second embodiment.
It has four nozzle rows for 00 nozzles for black, cyan, magenta, and yellow inks.

The heads 120 and 121 are the head holder 12
2 to secure the mutual positional accuracy between the two. The head holder 122 is mounted on a carriage 124.

Reference numeral 123 denotes an ink tank for each color.
And supplies the ink to the heads 120 and 121 from the head holder 122.

In the case of the present embodiment, the number of nozzles per head is half that of the second embodiment, so that there is an advantage that the manufacturing yield of the head is improved and the cost of the combined head is reduced. . In particular, when trying to increase the recording speed by increasing the number of nozzles,
It is an effective means for realizing with one head because it is difficult in terms of yield.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described.

In the first embodiment, the intermediate spur 100 and the spur 19 are provided over the entire width of the maximum recordable sheet of the recording apparatus.
The arrangement is not limited to this, and for example, both may be arranged in a staggered arrangement as shown in FIG.

In FIG. 7, reference numeral 125 denotes an intermediate spur,
A total of five of them are provided in the main scanning direction along the ribs 129 on the surface of the platen 128. Reference numeral 126 denotes a spur, provided with a total of six spurs. Reference numeral 127 denotes a paper discharge roller having six rubber portions corresponding to the spur 126.

As described above, the intermediate spur 125 and the spur 12
6. By arranging the paper discharge roller 127, it is possible to prevent the sheet from floating, although not as much as in the first embodiment. When the distance between the orifice surface and the sheet can be made longer than that in the first embodiment, the number of spurs and the number of sheet discharge rollers can be reduced to about half, so that an apparatus excellent in cost performance can be realized.

[0057]

As is apparent from the above description, according to the present invention, in a serial scan type ink jet recording apparatus which performs recording by scanning with an ink jet head, a plurality of ejection nozzles arranged in the sub scanning direction are used. One or more inkjet heads, recording medium support means provided at a position facing the plurality of nozzles, facing the recording medium support means, and upstream of the plurality of ejection nozzles At least one recording medium pressing means is provided at a position in the sub-scanning direction between the nozzle located at the most downstream position and the nozzle located at the most downstream position. The effect that quality can be ensured is obtained.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an inkjet recording apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view of a sheet feeding unit of the ink jet recording apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram of a head of the ink jet recording apparatus according to the first embodiment of the present invention as viewed from an orifice surface side.

FIG. 4 is a flowchart illustrating a recording operation of the ink jet recording apparatus according to the first embodiment of the present invention.

FIG. 5 is a view of a head of an ink jet recording apparatus according to Embodiment 2 of the present invention as viewed from an orifice surface side.

FIG. 6 is a cross-sectional view of a sheet feeding unit of an ink jet recording apparatus according to Embodiment 3 of the present invention.

FIG. 7 is an overall perspective view of an inkjet recording apparatus according to Embodiment 4 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chassis 3 Paper (recording medium) 6 LF roller 16 Platen 20 Bubble jet head 29 Carriage 33 Carriage shaft 35 Carriage rail 100 Intermediate spur (recording medium pressing means) 102 Black nozzle row 103 Cyan nozzle row 104 Magenta nozzle row 105 Yellow nozzle row 107 Escape (Escape part)

Claims (6)

[Claims] 1. A serial scan type ink jet recording apparatus that performs recording by scanning with an ink jet head, comprising: a single or plural ink jet heads having plural discharge nozzles arranged in a sub-scanning direction; A recording medium supporting means provided at a position opposed to the recording medium supporting means, and a sub-type between a nozzle located at the most upstream position and a nozzle located at the most downstream position among the plurality of ejection nozzles. An ink jet recording apparatus, comprising one or more recording medium pressing means provided at a position in a scanning direction. 2. An ink jet recording apparatus according to claim 1, wherein said recording medium pressing means is constituted by a roller or a spur which rotates following the conveyance of the recording medium. 3. An ink jet head having a plurality of nozzle rows for discharging different types of inks displaced in the sub-scanning direction, and a recording medium holding means positioned at a boundary between the plurality of nozzle rows. 3. The ink jet recording apparatus according to claim 1, wherein: 4. An ink jet recording apparatus according to claim 3, wherein no discharge nozzle exists at a boundary portion of said nozzle row. 5. A single or plural inkjet head having a plurality of nozzle rows for ejecting different kinds of inks arranged in parallel in the main scanning direction, and a recording medium press located within a range of the nozzle rows in the sub-scanning direction. 3. An ink jet recording apparatus according to claim 1, further comprising means. 6. An ink jet recording apparatus according to claim 1, further comprising an ink jet head having a relief portion at a portion facing a position in the sub-scanning direction where said recording medium pressing means exists. apparatus.