JPS6157364A - Carriage driver - Google Patents

Abstract

PURPOSE:To reduce the size of a carriage driver, by a construction wherein a plurality of piezoelectric elements are fixed to a carriage, the elements are driven to vibrate vibrating members fixed thereto so that tips of the members push a stator, and the carriage is moved by reaction to the pushing action. CONSTITUTION:When an AC voltage with an appropriate frequency is impressed on the piezoelectric element 13A, the vertical size of the element 13A is enlarged, whereby the vibrating piece 14A is moved downward to push the stator 15 in the direction of an arrow H, and due to the friction between the piece 14A and the stator 15, the reaction to the pushing is applied to the carriage 10, so that the carriage 10 is moved a predetermined distance in the direction of an arrow A. By thus moving a recording head provided on the carriage 10, recording is conducted on a recording paper 7. According to this carriage-driving method, the piezoelectric elements 13A, 13B and the vibrating pieces 14A, 14B are constituted in small size, are provided on the carriage, and the stator 15 is provided in a space-saving plate form and in the moving range of the carriage 10, so that the space occupied by the entire body of the carriage driver can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Technical Field The present invention relates to a carriage drive device, and more particularly to a carriage drive device that drives a carriage reciprocally in a linear direction.

[Prior Art] As this type of carriage 'tjAe device, a carriage drive device that drives a carriage of a print head in a printing apparatus is known. An example of the conventional configuration is shown in FIG.

In the same figure, the symbol l indicates a carriage on which a recording head (not shown) is mounted.
It is provided so as to be slidable in the direction. -t- A belt 3 is fixed to the shaft 1, and this belt 3 is attached to a pulley 4.
and a pulley 6 connected to the gA driving shaft of the stepping motor 5. The pulley 6 is rotated by a predetermined angle in the direction of arrow C or in the direction indicated by the arrow by the driving of the stepping motor 5 to cause the belt 3 to travel, thereby driving the carriage 1 in the entry direction or the direction B at a predetermined pitch. ing.

In this way, in the conventional 8-position carriage drive, a motor operated by electromagnetic force is used as the drive source, and in this case, the motor and its driving force transmission means are installed separately from the carriage and outside the range of movement of the carriage. It is common that

However, with this configuration, compared to the case where the motor is installed on the carrier or the carriage, the motor itself does not move, so the motor torque can be reduced accordingly, but on the other hand, the space occupied by the entire device is large, and the device is The drawback was that it was too large.

[Objective] The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide a carriage drive device that can be downsized, simple in structure, and inexpensive.

[Embodiments] Details of embodiments of the present invention will be described below with reference to FIG. 2 and the following drawings. In this example, a carriage drive IBJ for transporting rads to recording in an inkjet recording apparatus is used as an example.

[First Embodiment] FIG. 2 is a perspective view showing the main parts of an inkjet recording apparatus provided with a carriage drive device according to an embodiment of the present invention.

In the figure, the reference numeral 8 indicates a platen, and a recording paper 7 is wound around the outer peripheral surface of the platen. Also, two guide shafts 9.9 are installed near the front of the platen 8.
The carriage 10 is mounted horizontally parallel to the guide sleeves 9, 9, and the carriage 10 is mounted parallel to the axial direction of the platen 8.
It is pivotally supported so that it can freely slide in the direction.

An inkjet recording head (not shown) is mounted on the carriage 10.

In addition, a bifurcated position detector 11 is located at the bottom of the carriage 10.
A photodiode (not shown) as a light-emitting element and a phototransistor as a light-receiving element (not shown) are provided inside each of these two forks, and the pixel element is a slit plate 12 provided parallel to the travel path of the carriage 2. They are placed facing each other with the two sides in between. A large number of slits 12a are formed in the slit plate 1z, and these slits 1
The amount of light that the phototransistor receives from the photodiode via the phototransistor 2a changes depending on the position of the carriage 10.The zero position detector 11 detects the position of the carriage 10 by converting this change in the amount of light into a current change using the phototransistor. It is configured.

On the other hand, two piezoelectric elements 13A and 13B are fixed to the lower surface of the rear end of the carriage 10. This piezoelectric element 13
A and 13B are driven by an AC voltage applied from a drive circuit (not shown) to expand and contract, and their lower surfaces vibrate in the vertical direction in the figure, and each of the piezoelectric elements 13A and 13B has an elongated vibrating piece on its lower surface. 14A and 14B are implanted, and these vibrating pieces 14A and 14B are piezoelectric elements 13A.

It vibrates due to the drive of 13B.

The tip of the vibrating piece 14A is tilted toward the traveling direction B of the carriage 10, and the tip of the vibrating piece 14B is tilted toward the direction of travel B of the carriage 10.
When not vibrating, each tip is in contact with the upper surface of the stator 15 or is slightly separated from the upper surface.

The stator 15 is formed in the shape of an elongated flat plate, is placed below the carriage IO, and is attached to the guide shaft 9.
, that is, parallel to the travel path of the carriage 10.

Such piezoelectric elements 13A, 13B, vibrating pieces 14A, 1
4B and the stator 15 constitute an ultrasonic motor, and the carriage drive device of this embodiment is constituted by this ultrasonic motor.

Here, the principle of operation of the ultrasonic motor will be explained.

In FIG. 2, when no voltage is applied to the piezoelectric elements 13A and 13B, the tips of the vibrating pieces 14A and 14B are connected to the stator 1.
5, or is slightly away from the upper surface.

When an appropriate voltage is applied to one piezoelectric element 13A from this state, the vertical dimension of the piezoelectric element 13A expands, and its lower surface descends as shown by arrow G. This lowering causes the vibrating piece 14A to lower, and its inclination pushes the stator 15 in the direction of arrow H. And vibrating piece 14A, stator 1
5, the reaction force of the suppression in the H direction is transferred to the carrier 10 via the vibrating piece 14A and the piezoelectric element 13A.
This force causes the carriage 10 to move a predetermined distance in the direction of arrow A.

After that, when the voltage application is stopped, the piezoelectric element 13A contracts in its vertical dimension and returns to its original state.

Therefore, by applying an alternating current voltage of an appropriate frequency to the piezoelectric element 13A, the carriage 10 is continuously driven in the direction of arrow A by repeating the above operation.

77', :Pressure 'rr! in Figure 52! Since the vibrating piece 14B of the element 13B is inclined in the opposite direction to the vibrating piece 14A, the carriage 10 can be driven in the direction of arrow B, which is opposite to the above, by applying an AC voltage only to the piezoelectric element 13B. .

Next, the operation of the entire recording apparatus equipped with the carriage drive device of this embodiment as described above will be explained with reference to FIG.

First, an AC voltage of an appropriate frequency is applied to the piezoelectric element 13A from a drive circuit (not shown), and the gear ridge IO is driven in the direction of the arrow from the recording start position on the left side of the figure by the above-described drive operation. When the carriage 10 moves by a predetermined pitch and the position detector 11 detects that the recording head on the carriage 10 has moved to the recording position of one dot in the dot matrix pattern, the recording head is driven and ink droplets are ejected. Then, as shown by the black dot in the figure, one dot is recorded on the recording paper 7.

By repeating this operation, the carriage 10 reaches the recording end position n of one line on the right side of the figure, and when one line of recording is completed, the platen 8 is rotated by a predetermined angle in the direction of arrow E by driving means (not shown), and the recording paper 7 is One line is sent at a predetermined pitch in the direction of arrow F.

Thereafter, the carriage 10 is moved in the direction of arrow B by applying an alternating current voltage to the piezoelectric element 13B, and the name dot is recorded in the same manner as described above, and the next row is recorded. It will be done.

In this way, the ultrasonic motor of this embodiment moves the carriage 1
0 can be driven to perform recording.

According to the configuration of the carriage driving device using the ultrasonic motor of this embodiment as described above, the piezoelectric elements 13A, 13B and the vibrating pieces 14A, 14B are configured to be small as shown in the figure, and are provided on the carriage 10, Stator 15
Since it is formed into a plate shape that does not take up space and is provided within the movement range of the carriage 10, the overall space occupied can be made extremely small.

Further, the vibrating pieces 14A, 14B and the stator 15 have extremely simple structures and can be constructed at low cost, and the piezoelectric elements 13A, 1
Since 3B can also be obtained at low cost, the overall structure can be extremely inexpensive.

[Second Embodiment] In the first embodiment described above, carriage position control was performed via the position detector 11 and the slit plate 12. As a result, without the above configuration, gear ridge 1o
This is because it is difficult to strictly control the amount of movement and position of.

However, if such a position detecting means as described above is provided, the overall structure becomes complicated and the cost becomes high.

Therefore, in view of such problems, a second embodiment of the present invention, which is configured to accurately drive the carriage by a predetermined pinch without using the above-mentioned position detection means, will be described with reference to the drawings starting from FIG. This will be explained below. In each figure, the same or corresponding parts as in FIG. 2 are given the same or similar reference numerals.

FIG. 3 shows the configuration of the carriage drive device according to this embodiment.

As shown in the figure, on the lower surface of the carriage 10, in addition to the piezoelectric element 13A having the vibrating piece 14A described above, a piezoelectric element 13 is provided.
A' is provided, and a vibrating piece 14A' tilted in the same direction as the vibrating piece 14A is implanted in this piezoelectric element 13A'.

That is, in this embodiment, a plurality of (in this case, two) piezoelectric elements and vibrating pieces are provided in one direction (direction A) of the drive direction of the carrier 1o, and here, to simplify the explanation, the piezoelectric elements and vibrating pieces are provided in the direction B. The plurality of piezoelectric elements and vibrating pieces provided are omitted from illustration.

Further, in this embodiment, as shown in the figure, a large number of notches 16 are formed on the upper surface of the stator 15 at a predetermined pitch.
The vibrating pieces 14A, 14A' are configured not to contact the stator 15 at the notches 16, but to contact the stator 15 at the portions between the notches 16.

Further, the pitch corresponds to the pitch between adjacent dots of the dot matrix pattern used in the above-mentioned dot recording. In other words, each of the notches 16 corresponds to the recording position of one dot.

Furthermore, in relation to the pitch of the notches 16, the vibrating piece 14
The distance between the tips of the vibrating pieces 14A and 14A' is set to 1, for example, approximately 1.5 times the pitch in this case, so as to be different from the pitch.

14A' is configured so that it does not face above the notch 16 at the same time.

Next, the operation of this embodiment configured as described above will be explained with reference to FIG. 4 and subsequent figures.

First, the carriage 10 is in the position shown in FIG.
The tip of one vibrating piece 14A faces above the notch 16c,
The other vibrating piece 14A'' has a notch 16 on the stator 15.
Suppose you are facing between A and 16B.

This position is a one-dot recording position corresponding to the notch 16G, and a recording head (not shown) is first driven here.
A dot is recorded.

Next, a piezoelectric element 13A' that can come into contact with the stator 15 here
An alternating current voltage of an appropriate frequency is applied to the vibrator for a certain period of time to drive it as shown by arrow I in the figure, and the carriage 10 is moved in the direction of arrow A via the vibrating piece 14A' by the same operation as described above. .

As a result, the carriage 10 reaches the position shown in FIG. 5, but at this position the vibrating piece 14A' faces above the recess L6B and does not come into contact with the stator 15, so the carriage 10 does not move any further.

Next, as shown by arrow J in FIG.
is driven for a certain period of time, and the carriage 10 is roughly moved in the direction A via the vibrating piece 14A.

As a result, the carriage 10 reaches the position shown in FIG. 6, but at this position the vibrating piece 14A faces above the four parts 16D and does not come into contact with the stator 15, so the carriage 10 does not move any further and remains at the position shown. This position is a one-dot recording position corresponding to the notch 16D, which is one pitch away from the position shown in FIG. 4, and the recording head is driven here again to record the next dot.

By repeating the above operations, the carriage lO is driven in the A direction by exactly one pitch corresponding to each notch 16, and one dot is recorded at the recording position corresponding to each notch 16. Dot recording of the entire line is performed.

The recording of the next row is performed by driving the carriage 10 one pitch at a time in the B direction. This is performed by driving alternately for a fixed period of time.

In the above configuration, the piezoelectric element 13 may wear out due to long-term use of the device.
The amount of movement of the carriage 10 per 1 cycle of the AC voltage applied to A and 13A' decreases. Therefore, the frequency of the alternating current voltage and the application time for which it is alternately applied are determined by the carriage required for the vibrating element 14A to reach the notch 16D from the position shown in FIG. 10 or the amount of movement of the carriage IO required for the vibrating piece 14A' to reach the notch 16B from the position shown in FIG.

Therefore, even if the vibrating pieces 14A, 14A'' are worn out, the carriage 10 can be accurately driven one pitch at a time by the above-described operation.

As described above, according to this embodiment, the carry and carry 10 can be accurately driven one pitch at a time with a simple configuration without using complicated position detection means.

In this example, the piezoelectric element and the vibrating piece are mounted on the main cartridge l.
Two of them are provided for each of the driving directions of O, but it goes without saying that more than two of them may be provided. Furthermore, in this embodiment, notches 16 are provided in the stator 15 to provide a non-contact portion of the vibrating element and a contact portion therebetween at a predetermined pitch, but the non-contact and contact portions are provided by other four parts such as holes. It's okay.

Furthermore, the carriage drive devices of this embodiment and the first embodiment described above are not limited to inkjet recording devices, but can of course be applied to drive the carriage of any other system that transports a recording head. The present invention can be widely applied to carriage drive devices in various devices, such as driving the carriage of a reading head in an image reading device.

[Effects] As is clear from the above description, the carriage drive device of the present invention has a stator fixed along the travel path of the carriage, and a plurality of stators fixed to the carriage and driven by application of an alternating current voltage. The piezoelectric element is composed of a piezoelectric element and a plurality of vibrating members whose tips vibrate when driven by the piezoelectric element to press contact portions formed at a predetermined pitch on the upper surface of the stator, and whose tips have intervals different from the pitch, By driving a plurality of piezoelectric elements alternately for a predetermined period of time, the carriage is driven by the predetermined pitch by the reaction of the pressing force of the vibrating member, so it can be configured extremely compactly and does not require complicated positioning means. The excellent effect of being able to drive the carriage 7 accurately at a predetermined pitch with a simple and inexpensive configuration can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view illustrating the configuration and operation of a conventional carriage drive device, FIG. FIG. 3 is an explanatory diagram of the configuration of a second embodiment of the present invention, and FIGS. 4 to 6 are explanatory diagrams of the operation of the same embodiment. 10... Carriage 11... Position detector 12... Slit plates 13A, 13A', 13B... Piezoelectric elements 14A, 14
A', 14B River vibrating piece 15...Stator 16.16A-160...Notch Figure 1 Figure 3 1f5 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] a stator fixed along the travel path of the carriage;
A plurality of piezoelectric elements are fixed to a carriage and driven by application of an alternating current voltage, and when the piezoelectric elements are driven, they vibrate and their tips press contact portions formed at a predetermined pitch on the stator surface, so that the spacing between the tips is adjusted. A carriage comprising a plurality of vibrating members having different pitches, and driving the plurality of piezoelectric elements alternately at predetermined time intervals to drive the carriage by the pitch by a reaction of the pressing force of the vibrating members. Drive device.