JP2003103765A - Printing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively print a high resolution image regardless of the subject to be printed without increasing the number of ink ejecting nozzles. SOLUTION: A printing unit for printing moves a printing head having an ink ejecting nozzle relatively in a state facing a subject to be printed to have ink droplets ejected from the ink ejecting nozzle adhered. The unit comprises a pixel displacing means for displacing the printing head to a predetermined position, for printing with pixels displaced so as to improve the resolution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing device,
In particular, the present invention relates to an inkjet type printing apparatus capable of printing a high-resolution image regardless of the printing target.

[0002]

2. Description of the Related Art A (stationary) ink jet printer (printing apparatus) that prints on a recording medium (printing target) by ejecting ink droplets from a nozzle is usually a recording medium such as cut paper or roll paper. Is taken into the device and printed while being conveyed.

For example, in an ink jet printer using a so-called line head type print head in which nozzles for ejecting ink are arranged in one direction with respect to a print target, the print head is fixed and the print target is predetermined. While being positioned at the print position, the print target is continuously conveyed in the direction (sub-scanning direction) orthogonal to the nozzle array direction (main scanning direction), and print data is printed on the print target.

However, in such a stationary printer (inkjet printer), a printing object such as a cut sheet or roll paper is printed while being carried by a carrying mechanism, so that a thick object or the like that cannot be carried. Alternatively, printing could not be performed on something that could not be taken into the printing device in the first place, such as a floor or wall of a building. Therefore, it is possible to print on thick objects that cannot be transported conventionally and on the floor surface and wall surface of buildings.
A manual scanning type printing device has been developed.

For example, Japanese Utility Model Publication No. 8-1096 discloses that
A print head is housed in a movable housing that moves on a print target by manual scanning, and a wire dot pattern corresponding to print data is formed on a unit print surface partitioned and formed according to a predetermined character size in the print head. There is disclosed a manual scanning type printing device in which the wire dot pattern is sequentially formed according to the scanning speed of a movable housing and is transferred onto a print target surface via an ink donor film.

Further, in Japanese Patent Laid-Open No. 9-277565, a roller and an ink jet recording head are provided at the lower end inside the body of a manual printing device, and a pulley which rotates together with the roller is arranged on the roller, and from this pulley a belt is formed. The rotational force of the roller is transmitted to the rotary disc of the encoder by the controller, the rotational speed of the roller is detected, print data is output to the recording head according to the rotational speed of the roller, and the rotational force of the roller drives the print data. There is disclosed a manual printing apparatus capable of performing a printing operation regardless of the posture and orientation of the apparatus by performing printing by supplying ink from a ink tank to a recording head by a pump.

[0007]

However, since the donor film transfer type handy printer disclosed in Japanese Utility Model Publication No. 8-1096 is a contact type printer, it may depend on the surface roughness or unevenness of the transfer destination. However, there is a problem in that printing may not be possible, a high-resolution image cannot be obtained, and the cost of other devices is high, and color printing is difficult. Further, in a general (stationary type) head scanning printer, it is possible to output a high-resolution image regardless of the nozzle density by controlling the head feeding speed and the paper feeding speed, but the control is complicated. However, there is a problem that the device cost becomes high.

Further, since the hand-held type ink jet printer as disclosed in Japanese Patent Laid-Open No. 9-277565 mentioned above is a non-contact type, it is possible to print even if it is slightly rough or uneven. However, normally in a handy printer, the nozzle density of the head directly becomes the resolution in the main scanning direction of the output image, so a high resolution head must be installed in order to achieve high image quality, and still a high resolution image can be obtained. If it is attempted to obtain it, there is a problem that the cost of the device will rise.

The present invention has been made in view of the conventional problems described above, and is capable of printing a high-resolution image at a low cost regardless of the printing target without increasing the number of ink ejection nozzles. The challenge is to provide.

[0010]

In order to solve the above problems, the present invention provides a print head having an ink discharge nozzle facing a print target to which ink droplets discharged from the ink discharge nozzle adhere. In a printing device that relatively moves in a state where the printing is performed, the printing device is provided with pixel shifting means for displacing the print head to a predetermined position, and the pixel shifting is performed to increase the resolution by printing. A characteristic printing device is provided.

Further, a printing means including the print head is provided.
It is preferable that a manual scanning type is incorporated in a movable housing that moves on a print target by manual scanning.

Further, the print head is a line type head in which a plurality of ink discharge nozzles are connected in the main scanning direction, and the pixel shifting means moves the print head to the ink discharge nozzles in the main scanning direction. It is preferable to perform printing by performing pixel shift by displacing the nozzle pitch by 1/2.

Further, the print head is an area type head in which a plurality of ink discharge nozzles are arranged in a matrix in the x direction and the y direction which are orthogonal to each other, and the pixel shifting means includes the print head. It is preferable that when the movable housing is stopped, the pixels are displaced in at least one of the x direction and the y direction by ½ of the nozzle pitch of the ink discharge nozzles to perform pixel shifting and printing is performed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The printing apparatus of the present invention will be described below in detail with reference to the preferred embodiments shown in the accompanying drawings.

First, a first embodiment of the present invention will be described. The first embodiment realizes high resolution printing by performing pixel shift in a manual scanning type printing apparatus incorporating a printing means having an inkjet line type head. FIG. 1 shows an outline of a manual scanning type printing apparatus of this embodiment. As shown in FIG. 1, a manual scanning printer 10 includes a movable housing 12 that moves on a print target P by manual scanning, a roller 14 (a front roller 14a, a rear roller (auxiliary wheel) 14b), and a rotation of a roller 14. An encoder 18 for detecting the speed (rotation speed), a print head 20, an ink tank 22, and a controller 24 for controlling these are configured. Image information and control signals are input to the control device 24 of the manual scanning printer 10 from an input means 26 such as a keyboard or a host computer. In addition,
The manual scanning type printing apparatus 10 is manually scanned by the user in the direction indicated by an arrow A in the drawing while the roller 14 is in contact with the print target P.

The movable housing 12 is formed in a substantially rectangular column-shaped casing so that a person can easily hold it and scan the print target P, but the shape is not limited to this. In the lower part of the movable housing 12, the movable housing 12
Rollers (front roller 14a and rear roller 14b) for smoothly moving the (manual scanning printer 10 main body) onto the print target P are rotatably provided around shafts 16a and 16b, respectively. At this time, the rear roller 14b
May have a role of an auxiliary wheel that enables high-quality image recording by keeping the position of the print target P constant at the ink ejection position. Further, in this example, the rollers are the front roller 14a and the rear roller 14b.
Although two each, four in total, are installed, for example, one rear roller 14b may be provided, and the number of rollers may be three. Also, the rotation speed (rotation speed) of the front roller 14a
Is detected by the encoder 18 and input to the control device 24.

The print head 20 is an ink jet type printing means, and in this embodiment, it has a pixel shifting function for increasing the resolution, which will be described later. The ink tank 22 is for supplying ink to the print head 20, and the supply of the ink is controlled by the controller 24. The control device 24 is
A control signal input from the input means 26 and the encoder 18
Based on the rotation speed of the front roller 14a input from
Image information (print data) input from the input means 26
Is transmitted to the print head 20 and ink is ejected toward the print target P to perform printing.

FIG. 2 shows a schematic configuration of the print head 20 as a bottom view of the movable housing 12 as viewed from the lower side (printing target side). A nozzle substrate 30 is provided below the print head 20 (on the side facing the print target P).
Is provided with a plurality of ink ejection nozzles 30a. A portion (printing area) where the ink ejection nozzles 30a are provided is formed with a maximum recording width in a direction perpendicular to the manual scanning direction indicated by an arrow A in the figure. In addition, the nozzle substrate 30
Is arranged in the lower part of the print head 20 so as to be slightly movable (vibrating freely) in the left-right direction in the figure, and one end thereof is biased by a leaf spring 32.

A piezo element 34, which is a displacement element and is a piezoelectric element, is disposed at the other end of the nozzle substrate 30. The piezo element 34 is displaced by the piezo drive signal generated by the piezo control means 36, and repeatedly swells and contracts to vibrate slightly. Due to the displacement of the piezo element 34 and the biasing force of the leaf spring 32, the ink ejection nozzle 30a.
The nozzle substrate 30 having “” repeats minute vibrations along with minute fluctuations of the piezo element 34. At this time, the nozzle substrate 3
The displacement amount of 0 is 1/2 of the pitch of the ink discharge nozzle 30a.
The piezoelectric control means 36 is controlled by the control signal from the control device 24 so that

Ink is ejected from the ink ejection nozzle 30a in synchronization with the vibration of the nozzle substrate 30. That is, when the piezo element 34 is not displaced and the nozzle substrate 30 is in the original position, the ink is first ejected from the ink ejection nozzle 30a, and then the piezo element 34 is expanded and displaced to move the nozzle substrate 30 from the original position. Ink is ejected from the ink ejection nozzle 30a again at a position shifted by 1/2 pitch of the ink ejection nozzle 30a. In this way, by shifting the pixels by ½ pitch, the ink is ejected not only at the original positions but also at the positions of ½ pitch between them, so that the image resolution in the main scanning direction is increased. Is doubled.

As described above, while a pixel is shifted in the main scanning direction, a person holds the manual scanning type printer 10 in his hand and manually scans (subscans), thereby printing an image or the like two-dimensionally. To be done. By controlling the ejection timing of ink when performing sub-scanning, pixel shifting can be performed in the sub-scanning direction. As a result, higher resolution of the image is achieved. Although the piezo element is used as the means for performing the pixel shifting in the above embodiment, the pixel shifting means is not limited to this, and various other means can be used. Further, the means for urging the nozzle substrate 30 is not limited to the leaf spring 32.

Next, a second embodiment of the present invention will be described. The second embodiment also performs pixel shifting in a manual scanning type printing apparatus incorporating a printing means having a line type head, but in the present embodiment, heads of a plurality of lines (a plurality of nozzle rows) are arranged. The ink of different colors is supplied to each line to record a full-color image.

FIG. 3 shows an outline of the manual scanning type printer according to the second embodiment. In FIG. 3, (a) is a side view (view from the nozzle row direction), (b) is a front view (view from the manual (sub) scanning direction), and (c) is a bottom view (print target P). It is a view from the side).

The manual scanning type printer 110 shown in FIG.
It mainly includes a movable housing (main body) 112, legs 114, rollers 116, auxiliary wheels 117, and a print head 118. In this manual scanning type printer 110, a person (user) abuts a leg 114 with an ink ejection surface facing a print target P, and a nozzle array direction in a print head 118 (direction of arrow C in the figure, nozzle row). Direction (or main scanning direction), the full-color image is printed (recorded) on the print target P by manually moving (scanning) in the direction (sub-scanning direction) indicated by the arrow B in the drawing.
In addition, in the present embodiment, a means for performing pixel shift is installed in order to increase the resolution of the image. The pixel shifting means is not particularly limited, but here, for example, as shown in FIG. 3C, the control means 12 is provided on one side of the print head 118 in the nozzle row direction (direction of arrow C).
Attach the piezo element 120 controlled by 2,
The other side is biased by the coil spring 124. The biasing means is not limited to the coil spring, and may be a leaf spring or another elastic body.

Although not shown, the movable housing 112 is a box-shaped casing, and although not shown, controls the print head 118 and the piezo control means 122 for controlling the piezo element 120 and the like, and controls the entire manual scanning printer 110. Controller (CP
U) is included. Also, although not shown,
Print data and other control information are input to the manual scanning type printer 110 from the outside through input means such as a personal computer.

The roller 116 is provided with an encoder (not shown) for detecting the rotation speed (rotation speed) of the roller 116. The rotation speed of the roller 116 detected by the encoder is input to the control device, and based on this, the print head 1 is rotated.
The ink ejection timing from 18 is controlled. The print head 11 arranged on the lower surface of the movable housing 112
8 is installed so as to eject ink in a direction perpendicular to the lower surface of the movable housing 112.

The print head 118 has a plurality of nozzle rows (here, four rows) in which a large number of nozzles are arranged in the nozzle row direction (direction of arrow C). As shown in FIG. 3C, the nozzle rows 118Y, M (magenta) ink nozzle rows 118M, C (cyan) inks, which are arranged in the sub-scanning direction (arrow B direction), eject Y (yellow) inks. There are four nozzle rows, ie, a nozzle row 118C for ejecting the ink and a nozzle row 118K for ejecting the K (black) ink.

The manual scanning type printer 110 prints on the print target P
The print object P is two-dimensionally scanned by the nozzle row of the print head 118 by being placed on top and moved in the sub-scanning direction (the direction of arrow B in the drawing) by the user. At this time, the control device calculates the moving amount of the manual scanning type printing device 110 from the rotation speed of the roller 116 detected by the encoder, adjusts the ink ejection timing in synchronization with this moving amount, and responds to the recorded image. Modulated and ejecting ink of each color from the print head 118,
Full-color images of Y, M, C, and K are recorded on the print target P.

At this time, in the present embodiment,
The print head 118 (each ink ejection nozzle) is moved in the nozzle row direction (main scanning direction, arrow B direction) by the pixel shifting means of the piezo element 120 and the coil spring 124 provided at each end of the print head 118 in the nozzle row direction. High resolution is achieved by slightly vibrating the pixel) and shifting the pixel. In addition, the control device naturally discharges the ink in synchronization with the pixel shift. After all, while performing pixel shifting in the nozzle row direction (main scanning direction), manual scanning is performed by the user in the direction (sub scanning direction) orthogonal to that, and a high resolution two-dimensional image is recorded.

Another example of this embodiment is shown in FIG.
As shown in FIG. 4, in this example, the print head 128 is
Instead of forming a plurality of nozzle rows on one substrate as shown in FIG. 3C, each nozzle row 118Y, 118Y is formed.
Different substrates are provided for M, 118C, and 118K, and piezo elements 120a, 120b, and 120 are provided for each nozzle row.
c, 120d and coil springs 124a, 124b, 1
24c and 124d are installed. The ink ejection timing is controlled for each nozzle row, and pixel shifting is performed for each nozzle row.

By controlling the ink ejection timing for each nozzle row and shifting the pixels in this way, even when the sub-scanning speed becomes somewhat unstable,
It is possible to sufficiently cope with the situation, and it is possible to obtain a high-resolution and high-resolution image.

Next, a third embodiment of the present invention will be described. The manual scanning type printer of the third embodiment also has substantially the same configuration as that of the second embodiment shown in FIG. The present embodiment is different from the previous embodiments in that the print head of this embodiment is an area type head. A print head according to this embodiment is shown in FIG.

As shown in FIG. 5, the print head 218 of this embodiment is an area type head, and a plurality of nozzles 218a are arranged in a matrix on a nozzle substrate having a square shape, for example. Therefore, the manual scanning type printing apparatus of the present embodiment performs printing similar to a so-called electronic stamp in which the apparatus is placed on a printing target and ink is simultaneously ejected from each nozzle 218a to form an image at one time. is there.

Further, the print head 218 has a pair of piezoelectric elements 220a and a coil spring 224a.
18, and another pair of piezo elements 220b and a coil spring 224b are arranged so as to sandwich the print head 218 in a direction orthogonal to these. The piezo element 220a is a control means 222a.
The piezoelectric element 220b is controlled by the control means 22.
Controlled by 2b. By thus providing the two piezo elements 220a and 220b in the directions orthogonal to each other, the print head 218 can be vibrated in the two directions orthogonal to each other, and the pixels can be shifted two-dimensionally.

FIG. 6 shows a concrete pixel shifting method.
In FIG. 6, the position of each nozzle 218a is indicated by ●. First, after ejecting the ink at the position ●, the ink is displaced rightward in FIG. 6 by ½ of the nozzle pitch to eject the ink at the position ○. Next, the ink is ejected from the position of ◯ in the downward direction in FIG. 6 by ½ of the nozzle pitch to reach the position of Δ.
Next, the ink is ejected so as to be shifted from the position of Δ to the left in FIG. 6 by ½ of the nozzle pitch to the position of □. Then return to the ● position again.

As described above, in the case of the area type head,
If you place the manual scanning printer at a certain position on the print target,
Therefore, when printing one image, the print head 218 is moved by the piezo elements 220a and 220b at that position, and pixel shifting is performed three times. Then the user
When this manual scanning type printer is lifted and placed at the next position on the printing target, the image is printed at that position while similarly performing pixel shifting three times. As described above, in the case of the manual scanning type printing apparatus having the area type head, so-called sub-scanning which is different from the case of the line type head is not performed, so that the number of pixel shifts is further increased to further increase the resolution. You may When the number of pixel shifts is increased, the time required for printing is increased, but in the case of the area type head, printing is performed in a state where the stamp is pushed, so the printing time does not matter so much.

Although each of the embodiments described above is a manual scanning type printing apparatus, the present invention can be applied to a stationary type ink jet printer. Also in the case of a stationary type inkjet printer, similarly to each of the above-described embodiments, a pixel shift means such as a piezo element is installed in the print head, and ink is ejected in synchronism with the pixel shift to achieve high resolution. Images can be obtained.

Although the printing apparatus of the present invention has been described in detail above, the present invention is not limited to the above embodiments, and various improvements and changes are made without departing from the gist of the present invention. Of course it is okay.

[0039]

As described above, according to the present invention, it is possible to obtain a high-quality image at a low cost, without increasing the number of ink ejection nozzles, and at a high resolution regardless of the printing target. .

[Brief description of drawings]

FIG. 1 is a side view showing an outline of a manual scanning type printing apparatus according to a first embodiment of the present invention.

FIG. 2 is a bottom view showing a print head of the manual scanning type printing apparatus of FIG.

FIG. 3 is a side view, FIG. 3B is a front view, and FIG. 3C is a bottom view showing an outline of a manual scanning type printer according to a second embodiment of the invention.

FIG. 4 is an explanatory diagram showing another example of the print head of the manual scanning type printer according to the second embodiment.

FIG. 5 is an explanatory diagram showing a print head of a manual scanning type printer according to a third embodiment of the invention.

FIG. 6 is an explanatory diagram showing a pixel shifting method according to a third embodiment.

[Explanation of symbols]

10, 110 Manual scanning type printing device 12, 112 Movable housing 14, 116 Roller 14a Front roller 14b Rear roller 16a, 16b Shaft 18 Encoder 20, 118, 128, 218 Print head 22, Ink tank 24 Control device 26 Input means 30 Nozzle Substrate 30a Ink ejection nozzle 32 Leaf springs 34, 120, 120a to 120d, 220a, 220
b piezo elements 36, 122, 222a, 222b piezo control means 114 legs 124a to 124d coil springs

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiya Kojima             798 Miyadai, Kaisei-cho, Ashigarakami-gun, Kanagawa Prefecture             Shishi Film Co., Ltd. F term (reference) 2C056 EA04 EC78 FA09 HA11 HA22

Claims (4)

[Claims] 1. A print head having an ink discharge nozzle,
A printing device that prints by relatively moving an ink droplet ejected from the ink ejection nozzle in a facing state with respect to a print object to which the ink droplet adheres, the pixel shifting means displacing the print head to a predetermined position. The printing device is characterized in that the resolution is increased by performing pixel shifting and printing. 2. The printing apparatus according to claim 1, wherein the printing means including the print head is incorporated into a movable housing which moves on a printing target by manual scanning, and is a manual scanning type. 3. The print head is a line-type head in which a plurality of ink discharge nozzles are connected in the main scanning direction, and the pixel shifting means moves the print head to the ink discharge nozzles in the main scanning direction. 1/2 of nozzle pitch
3. The printing apparatus according to claim 1, wherein the printing is performed by displacing only the pixel to shift the pixel. 4. The print head is an area-type head in which a plurality of ink ejection nozzles are arranged in a matrix in an x direction and a y direction which are orthogonal to each other, and the pixel shifting means includes the print head, 3. The printing according to claim 1, wherein when the movable housing is stopped, the pixel is displaced in at least one of the x direction and the y direction by ½ of the nozzle pitch of the ink discharge nozzles to perform pixel shift, and printing is performed. Printing device.