JPH10287005A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a good quality image by reducing image noise due to feeding irregularity by a low-cost composition. SOLUTION: The recorder comprises a recording head 5 that records linearly on a recording sheet 10 and a speed reducing interlocking mechanism 15 having rotors 16 to 19 and a feed roller 11, and is equipped with a feeding means that feeds the recording sheet 10 in a direction perpendicular to the recording direction of the recording head 5. In such a case, the amount of feeding by an integral number of revolutions of optional toothed rotors 16 to 19 in the speed reducing interlocking mechanism 15 is matched with the amount of movement of the recording head 5 to the next recording position. Therefore, it is possible to obtain a good quality image without increasing costs involved by preventing an feeding error of optional toothed rotors 16 to 19 from affecting the feeding accuracy of the recording sheet 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus, and more particularly, to recording and recording in a line by ejecting ink or toner from a recording head section to a recording sheet in accordance with image data or irradiating light. The present invention relates to an image recording apparatus for recording an image by feeding a sheet in a direction orthogonal to a recording direction.

[0002]

2. Description of the Related Art In an ink jet printer as an example of the above-described image recording apparatus, image recording is performed by sequentially feeding recording sheets in a sub-scanning direction while reciprocating a carriage on which a recording head is mounted in a main scanning direction. It is configured to perform. The recording head unit is known to use an electromechanical conversion type in which a piezoelectric element changes the volume to fly ink droplets, or an electrothermal conversion type in which a heating element generates bubbles and the ink droplets fly according to the volume change. ing. The feeding means for feeding the recording sheet in the sub-scanning direction includes:
Generally, it is composed of a drive motor, a reduction gear train, and a feed roller.

[0003]

One of the causes of the image noise of the recorded image is uneven feeding of the recording sheet by the feeding means. In order to reduce the uneven feed, it is necessary to increase the precision of the gears in the reduction gear train, but there is a problem that using high precision gears increases the cost.

An object of the present invention is to provide an image recording apparatus capable of obtaining a high quality image by reducing image noise due to uneven feeding with a low-cost configuration in view of the above conventional problems.

[0005]

According to the present invention, there is provided an image recording apparatus comprising: a recording head for recording a recording sheet in a line;
An arbitrary toothed rotary body in the speed reduction interlocking mechanism, comprising: a feed motor that includes a drive motor and a reduction interlocking mechanism having a toothed rotary body and a feed roller, and that feeds the recording sheet in a direction orthogonal to the recording direction by the recording head unit. The feed amount sent by the integer number of rotations is made to match the amount of movement of the print head unit to the next print position.

According to this, it is only necessary to set the ratio of the number of teeth so that the feed amount per rotation of an arbitrary toothed rotator becomes a predetermined amount corresponding to the movement amount to the next recording position. Since a feed error caused by an arbitrary toothed rotating body does not affect the feed accuracy of the recording sheet, image noise due to uneven feed can be reduced and a high quality image can be obtained without increasing the cost.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet printer according to an embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an ink-jet printer; 2, a main body thereof; and 3, a paper feeding device such as a cut sheet feeder disposed on the back of the main body 2, which feeds a recording sheet 10. . Reference numeral 4 denotes a carriage on which a recording head unit 5 is mounted.

The carriage 4 is supported by lower guide means 6 and upper guide means 7 so as to be able to reciprocate in a main scanning direction orthogonal to the recording sheet feed direction, and is driven by a drive motor (not shown) to drive a pulley 8a and a tension. It is driven reciprocally via a pulley 8b and a timing belt 9. Reference numeral 11 denotes a feed roller that feeds the recording sheet 10 by a predetermined amount in synchronization with the recording operation of the recording head unit 5, and reference numeral 12 denotes a platen that also serves as a guide plate for guiding the recording sheet 10 directly below the recording head unit 5. Reference numeral 13 denotes a discharge roller for discharging the recording sheet 10.

At the time of recording, the carriage 4 moves the recording sheet 1
The main scanning is performed in the width direction of 0, and one or a plurality of lines of images are recorded by the recording head unit 5 mounted on the carriage 4.

Each time recording by one main scan is completed, the recording sheet 10 is fed vertically by a feed roller 11 and is sub-scanned. The image is recorded on the recording sheet 10 in this way, and the recording sheet 10 that has passed through the recording section is discharged by the discharge roller 13 arranged on the downstream side in the transport direction.

As shown in FIG. 2, the feed roller 11 is driven by a drive motor 14 comprising a stepping motor via a reduction gear interlocking mechanism 15.
The reduction gear interlocking mechanism 15 includes a driving gear 16 fixed to a motor shaft and a first interlocking gear 17 meshed with the driving gear 16.
And the second interlocking gear 1 integrally connected to the first interlocking gear 17
8 and a driven gear 19 meshed with the second interlocking gear 18 and fixed to the roller shaft of the feed roller 11.

As shown in FIGS. 3 and 4, the recording head section 5 has a head plate section 21, a head holder 22 for supporting the periphery thereof, and Y (yellow) and M ( A piezoelectric element (PZT) group 23 disposed corresponding to each color of magenta) and C (cyan), a ceramic substrate 24 supporting each piezoelectric element group 23, and a back surface of each ceramic substrate 24 And wiring section 25
And a back plate 26 on which the recording head unit 20 is disposed. It should be noted that the recording head unit 5 of the present embodiment has a similar configuration in which two piezoelectric element groups are arranged in parallel.
k (black) dedicated print head unit (not shown)
Are also arranged in parallel.

The head plate portion 21 includes a nozzle plate 31 in which a plurality of (37 in the illustrated example) discharge nozzles 30 for each color are formed in a line and parallel to each other, and a common ink chamber 32 for forming a common ink chamber 32. An ink chamber forming plate 33, an inlet plate 36 having an inlet 34 for supplying ink from the common ink chamber 32 to each ink chamber 35, and an elongated channel-shaped ink chamber 3 corresponding to each ejection nozzle 30;
And the ink chamber forming plate 37 in which the ink chambers 5 are formed.
Partition walls 38 for closing the lower surface of the piezoelectric element group are sequentially laminated and integrally bonded to each other. The inlet 34 of the inlet plate 36 is formed so that one end of the ink chamber 35 communicates with the common ink chamber 32, and the other end of the ink chamber 35 is formed so as to correspond to the ejection nozzle 30. In addition, communication holes 39 and 40 are formed in the inlet plate 36 and the common ink chamber forming plate 33 to communicate the other end of the ink chamber 35 and the discharge nozzle 30. The common ink chamber 32 has a head holder 2.
The ink is supplied from a predetermined ink tank 7 through a supply passage 47 formed in the ink tank 2.

Each of the piezoelectric elements 41 of the piezoelectric element group 23 is shown in FIG.
As shown in (a), it is composed of a laminated type in which piezo green sheets and electrodes are alternately laminated, and is expanded and contracted in the thickness direction (lamination direction) (d ₃₃ mode expansion and contraction) by voltage application to both ends. The configuration is such that the volume and pressure of the elongated channel-shaped ink chamber 35 corresponding to each ejection nozzle 30 are changed via the partition plate 38 to eject ink droplets. And ensuring high responsiveness By thus utilizing the expansion and contraction of the d ₃₃ mode of the piezoelectric element 41.

The piezoelectric element 41 includes a ceramic base 24
An elongated piezoelectric element plate 42 manufactured in advance is disposed along the arrangement direction of the discharge nozzles 30 and integrally bonded, and then a plurality of parallel separate grooves 43 are processed by a dicer. And a support portion 44 located between adjacent piezoelectric elements. Then, connection terminals 45 and 46 are formed from the lead frame so as to be in contact with electrodes formed on both end surfaces of each piezoelectric element 41 from the wiring portion 25. The connection terminal 45 on one end of the piezoelectric element 41 is connected to the common electrode side wiring portion of the wiring portion 25 which is grounded, and the connection terminal 46 on the other end side is connected to the individual electrode side wiring portion of the wiring portion 25. .

Thus, when a voltage is applied between the connection terminals 45 and 46 at both ends of the required piezoelectric element 41, the volume and pressure of the ink chamber 35 are increased via the partition plate 38 due to the expansion and contraction of the piezoelectric element 41 in the thickness direction. Then, the ink in the ink chamber 35 is discharged from the discharge nozzle 30 through the communication holes 39 and 40, flies as ink droplets toward the recording sheet 10, and is recorded on the recording sheet 10.

In the ink jet printer 1 having the above-described overall configuration, the gears 16 to 19 of the reduction gear interlocking mechanism 15 are used.
Are set as Z _A , Z _B , Z _C , and Z _D , respectively, and the diameter of the feed roller 11 is set as D. Further, for simplicity of explanation, as shown in FIG. 5, five ejection nozzles 30 are arranged at 72 npi in the recording head unit 5 and this recording head unit 5 records an image at 360 dpi. explain. In this case, the recording roller 10 is fed by the feed roller 11 four times at a pitch of 360 dpi and one time at a pitch of 360 dpi.
This feed cycle is repeated with a feed combination of dpi × 21 (= L ₁ ) as one cycle. In addition, 1
The cycle feed amount L ₂ is given by L ₂ = 360 dpi × 25.

Here, for example, the ratio of the number of teeth between Z _C and Z _D is given by Z _C / Z _D = L ₁ / πD or Z _C / Z _D = L ₂ /
By setting πD or its approximate value, the feed amount per rotation of the second interlocking gear 18 (the number of teeth Z _C ) becomes the above-described feed amount L ₁ or L ₂ , and the first and second interlocking Gear 1
Since the gears 7 and 18 are integrally connected, these gears 1
The feed error due to 7 and 18 does not affect the feed accuracy of the recording sheet 10. Therefore, these gears 17, 1
8, it is possible to reduce the feeding unevenness by the feeding accuracy error, and reduce the image noise to obtain a high quality image.

Next, a specific embodiment will be described.

(Embodiment 1) Each of the gears 16 to 19 has a module of 0.5 and the number of teeth is Z _A = 12, Z
_{It is} assumed that _B = 32, Z _C = 16, Z _D = 42, and the diameter D of the feed roller 11 is 7.54 mm. Further, assuming that the accumulated pitch errors of the gears 16 to 19 are all 30 μm, the rotation angle of each gear and its feed accuracy error occur in a state similar to a sine wave as shown in FIG.

In this case, the feed amount per one rotation of each of the gears 16 to 19 and the feed accuracy error are as follows.

Feed amount per rotation Feed error per rotation Gear 19 23.69 mm ± 5.38 μm Gear 18 9.02 mm ± 5.38 μm Gear 17 9.02 mm ± 2.69 μm Gear 16 3.38 mm ± 2.69 μm Here, assuming that the feed error caused by the gears 17 and 18 does not affect the feed accuracy of the recording sheet 10 and can be set to 0 as described above, the total feed accuracy error is reduced by half to ±± 14.14 μm.
It can be reduced to 8.07 μm.

(Embodiment 2) Next, the number of teeth of each gear is Z _A =
_{14, Z B = 43, Z} C = 17, Z D = 42, when the diameter D = 7.99mm of the feed roller 11, the gear 1
The feed amount per feed and the feed accuracy error of 6 to 19 are as follows.

Feed amount per rotation Feed error per rotation Gear 19 25.09 mm ± 5.71 μm Gear 18 10.40 mm ± 5.71 μm Gear 17 10.40 mm ± 2.26 μm Gear 16 3.39 mm ± 2.26 μm Total ± 15.93 μm Here, assuming that the feed error due to the gears 17 and 18 does not affect the feed accuracy of the recording sheet 10 as described above and can be set to 0, the total feed accuracy error is ± 7. 97
μm.

Next, as shown in FIGS. 3 and 4, a case will be examined where 37 print nozzles 30 are formed in the print head unit 5 at 90 npi and an image is printed at 360 dpi. In this case, three feeds of 360 dpi,
One cycle of feed combining 360 dpi × 145 one feed is repeated. In this case, the feed length of one cycle is 25.4 × (3 + 145) / 360 =
10.44 mm. The feed amount in one cycle is almost the same as the feed amount of one rotation of the gears 17 and 18 in the second embodiment, and the feed error of the gears 17 and 18 is close to zero. Therefore, at the time of this image recording, the maximum value of the paper feed error in one-cycle feed can be set to ± 7.97 μm as described above by selecting the ratio of the number of teeth in the second embodiment. Approximately 51% compared to ± 16.14 μm when the number of teeth ratio is selected
Can be obtained.

In the description of the above-described embodiment, an example is shown in which the reduction gear interlocking mechanism 15 composed of a gear train is used as the reduction interlocking mechanism having the toothed rotating body. A speed reduction interlocking mechanism using a belt (belt) may be applied. In this case, the same effect can be obtained by matching the feed amount fed by an integer number of rotations of an arbitrary toothed pulley with the feed amount of one cycle of image formation. The attainment is clear without further explanation.

[0028]

According to the image recording apparatus of the present invention, as is apparent from the above description, the feed amount fed by an integer number of rotations of an arbitrary toothed rotator in the deceleration interlocking mechanism is set to a value next to the recording head unit. By setting the ratio of the number of teeth of the toothed rotator in the deceleration interlocking mechanism as described above by matching the movement amount to the recording position of No longer affect
Therefore, it is possible to reduce the image noise due to the uneven feeding without increasing the cost, and to obtain a high quality image.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a main mechanism of an ink jet printer which is an embodiment of an image recording apparatus of the present invention.

FIG. 2 is a configuration diagram of a feed roller driving unit in the embodiment.

FIGS. 3A and 3B show a recording head unit according to the embodiment, wherein FIG. 3A is a plan view and FIG. 3B is a longitudinal sectional view.

FIGS. 4A and 4B show a detailed configuration of a main part of the recording head unit according to the embodiment, wherein FIG. 4A is a longitudinal sectional view, and FIG.
It is a XX arrow top view.

FIG. 5 is an explanatory diagram of main scanning and sub-scanning during image recording according to the embodiment.

FIG. 6 is an explanatory diagram of a feed error of each gear in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet printer (image recording device) 5 Recording head part 10 Recording sheet 11 Feed roller 14 Drive motor 15 Reduction gear interlock mechanism 16 Drive gear 17 1st interlock gear 18 2nd interlock gear 19 Follower gear

Claims (1)

[Claims] 1. A recording head section for recording a recording sheet in a line, a speed reduction interlocking mechanism having a drive motor and a toothed rotary body, and a feed roller, and a direction perpendicular to the recording direction of the recording sheet by the recording head section. Feeding means for feeding an arbitrary number of rotations of the toothed rotating body in the deceleration interlocking mechanism to an integer number of rotations of the recording head unit to the next recording position. Image recording device.