JP2000238359A - Recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately prevent the generation of overshoot or minute vibration at a time of the movement of a carriage by relatively simple constitution. SOLUTION: A carriage 10 moving the recording head 18 provided on a guide shaft 28 constituted of SUS 303 in a slidable manner in the lateral direction of recording paper is provided with an electromagnet 12 at the center position of the region opposed to the guide shaft 28 from above and an electromagnet control part 15 controls the excitation state of the electromagnet 12 in synchronous relation to the control of the moving speed of the carriage by a motor drive IC to control the timing generating slide resistance between the carriage 10 and the guide shaft 28 and the magnitude of slide resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a recording apparatus,
In particular, the present invention relates to a recording apparatus that performs recording on a recording medium by scanning a recording head.

[0002]

2. Description of the Related Art As one of recording apparatuses for printing on recording media such as paper and OHP sheets, there is a serial recording apparatus. This serial type recording apparatus records characters and images by ejecting ink onto recording paper by a recording head while scanning a carriage equipped with a recording head over a recording medium conveyed intermittently. This is referred to as recording.).

[0003] In a serial type recording apparatus having such a configuration, a speed is generally adjusted by controlling the number of rotations of a motor.
A major problem is to prevent the vibration of the carriage due to the vibration of the drive motor and the belt transmitting the rotational force of the drive motor from causing the carriage to vibrate and thereby blur characters and images being recorded.

For this reason, Japanese Patent Application Laid-Open No. Hei 2-187378 discloses that a guide shaft for guiding and holding a carrier, which is provided in a direction perpendicular to the feeding direction of a recording medium, is made of a magnetic material, and a semi-circular portion is formed on a sliding bearing portion of the carrier. There is disclosed a carrier braking mechanism in which an arc-shaped electromagnet is attached, and an inner arc surface of the semi-arc-shaped electromagnet covers an outer peripheral portion of the guide shaft.

[0005] The carrier braking mechanism excites the electromagnet by applying a current to the electromagnet when stopping the carrier or changing the image recording direction, and attracts the guide shaft by the electromagnet to stop the carrier or record the image. The vibration of the carrier generated when the direction is changed is reduced, and the displacement of ruled lines and the blurring of characters are prevented.

Japanese Patent Application Laid-Open No. Hei 9-240098 discloses a carriage speed detecting section for detecting a speed change during one scanning time of a print head, a storage means for storing data detected by the carriage speed detecting section, and a carriage. A recording device that calculates a correction value for correcting the data detected by the carriage speed detection unit based on the predetermined value data, with the data initially detected by the speed detection unit as the predetermined value data. It has been disclosed.

This printing apparatus corrects the fluctuation of the printhead speed based on the initial printhead speed, thereby reducing the deterioration of the print image due to the fluctuation of the carriage speed without using a complicated apparatus. It is a low price.

[0008]

The moving state of the carriage is controlled in the order of acceleration, constant speed, and deceleration. That is, the image is accelerated at the start of the movement, and becomes a constant speed when the scanning speed reaches a predetermined constant scanning speed, and the image is recorded by the recording head. When image recording at a constant scanning speed and a constant distance is completed, the carriage is decelerated and stopped.

Thereafter, the same operation of acceleration, constant speed, and deceleration as described above is repeated again in the opposite direction, and image recording is performed in the opposite direction from the next line. Alternatively, the image is returned to the image recording start position again, and image recording is performed by repeating the same acceleration, constant speed, and deceleration operations as described above.

In order to reduce the size and speed of the recording apparatus, it is effective to reduce the time and distance required for accelerating and decelerating the carriage.
As shown in (1), there is a problem that the target scanning speed is reached at the time of acceleration, a large overshoot occurs, and the recording image quality deteriorates. Also, during the constant speed movement of the carriage, there is a possibility that a minute vibration as shown in FIG. 8 may occur.

In order to prevent such overshoot and minute vibration, it is conceivable to increase the frictional load by applying a pressing force to the guide shaft from the carriage side. However, in such a configuration, since a constant load is always applied to the guide shaft from the carriage side, the load applied to the motor that moves the carriage when the carriage is accelerated is particularly large, and a high-rated and expensive motor is required. Therefore, the price becomes high, which is not preferable.

In the configuration of the above-mentioned Japanese Patent Application Laid-Open No. 2-187378, such overshoot can be relatively suppressed. However, since the bearing portion of the carriage is an arc-shaped electromagnet, a gap between the carriage and the guide holding guide shaft is provided. In this case, there is a problem that a small vibration as shown in FIG. 8 is generated during image recording. In addition, it is difficult to adjust the direction of the line of magnetic force because of the arc shape.

That is, in order to effectively brake the carrier, it is desirable to generate magnetic force lines in a direction perpendicular to the axis of the guide shaft for guiding and holding. With this configuration, the winding device and the electromagnet Is very difficult and impractical to manufacture. In addition, when the magnetic field lines are generated in a direction parallel to the axis of the guide holding guide shaft, the magnetic field acting between the inner peripheral surface of the electromagnet and the outer peripheral surface of the guide holding guide shaft becomes uneven when the magnetic force is generated by the electromagnet. Therefore, there is a disadvantage that the contact point is not stable.

The configuration disclosed in Japanese Patent Application Laid-Open No. 9-240098 requires an expensive linear encoder and a sensor as its detecting means, which is not preferable in terms of cost. It is also conceivable to perform correction based on representative speed data stored in advance in the storage means. However, in such a configuration, highly accurate correction can be performed due to a difference in image recording position or a variation in a recording apparatus. Can not.

In view of the above, it is an object of the present invention to provide a recording apparatus which can prevent the occurrence of overshoot and minute vibration during the movement of a carriage with a relatively simple configuration and with high accuracy.

[0016]

In order to achieve the above object, the present invention provides a guide shaft made of a magnetic material arranged so as to intersect with a feed direction of a recording medium, and a magnetic field generation at a position facing the guide shaft. And a carriage slidably mounted on the guide shaft, a moving unit for reciprocating the carriage along the guide shaft, and generating the magnetic field during the movement of the carriage. Sliding resistance adjusting means for controlling the strength of the magnetic field generated by the means to adjust the magnitude of the sliding resistance generated between the guide shaft and the carrier;
Is provided.

That is, according to the first aspect of the present invention, the carriage is provided with magnetic field generating means so as to face the guide shaft made of a magnetic material, and when the magnetic field generating means generates a magnetic field, the magnetic field is applied from the carriage side to the guide shaft. By acting, the carriage is attracted to a guide shaft made of a magnetic material. As described above, when the carriage is attracted to the guide shaft, the sliding resistance generated between the carriage and the guide shaft increases, so that the moving speed of the carriage is reduced accordingly.

Further, since the magnetic field generating means is provided to face the guide shaft, it is not in contact with the guide shaft. Therefore, the slidability of the carrier does not deteriorate due to the contact of the magnetic field generating means with the guide shaft, and a material having good slidability can be used for the sliding surface of the carriage. Also, in terms of material, it is possible to suppress minute vibrations that are likely to occur during the movement of the carriage.

Such a magnetic field generating means is provided on the guide shaft by raising and lowering, for example, an electromagnet which generates a magnetic field by switching a power source or a permanent magnet which is provided so as to be movable in a direction perpendicular to the axis of the guide shaft. A permanent magnet is provided on the carrier side and a door member made of a dielectric material is provided on the guide shaft side via an opening provided on the side of the carrier on the guide shaft side, and a door member made of a dielectric material is provided by opening and closing the door member. A configuration in which a magnetic field acts on the guide shaft can be adopted.

The sliding resistance adjusting means controls the strength of the magnetic field generated by the magnetic field generating means during the movement of the carriage, so that the magnitude of the sliding resistance generated between the guide shaft and the carrier is controlled. Is adjusted to prevent the carriage from vibrating or shaking when the moving speed of the carriage changes or when the carriage moves at a constant speed.

For example, the moving means accelerates and moves the carriage to the image recording start position, moves the carriage at a predetermined constant speed in the image recording area, and terminates the image recording. When controlling the movement of the carriage so as to decelerate the carriage from a position, the sliding resistance adjusting means uses a magnetic field generating means when the moving means switches the moving speed of the carriage from acceleration to a predetermined constant speed. Control is performed so that a strong magnetic field is generated to increase the sliding resistance generated between the guide shaft and the carrier.

Accordingly, the carrier is strongly attracted to the guide shaft by the strong magnetic field generated between the guide shaft and the carrier when the moving speed of the carrier is switched from the acceleration at which overshoot is likely to occur to the predetermined constant speed. As a result, the sliding resistance is increased, and as shown in FIG. 6, overshoot is suppressed, so that the carriage speed can be smoothly switched.

Further, when the moving means moves the carriage at a predetermined constant speed, the sliding resistance adjusting means generates a magnetic field so that the carrier is attracted to the guide shaft with such strength that small vibration does not occur. The intensity of the magnetic field generated by the means is adjusted.

Further, when the moving means decelerates the speed of the carriage from a predetermined constant speed, the sliding resistance adjusting means generates a strong magnetic field again by the magnetic field generating means and causes the sliding resistance adjusting means to generate a magnetic field between the guide shaft and the carrier. Control is performed to increase the generated sliding resistance.

As a result, the carrier is strongly attracted to the guide shaft by the strong magnetic field generated between the guide shaft and the carrier, the sliding resistance increases, and the moving speed of the carrier decreases. The carrier can be stopped without applying a large load to the motor.

According to a third aspect of the present invention, in the recording apparatus according to the first or second aspect, the magnetic field generating means is constituted by one or more electromagnets, and the one or more electromagnets are provided by the carriage. Are arranged so that the acting force is symmetric with respect to the center of gravity of the carriage in a region facing the guide shaft of the carriage.

That is, according to the third aspect of the present invention, the magnetic field generating means comprises one or more electromagnets. The electromagnet is not only capable of accurately and easily controlling the strength of the magnetic field to be generated, but also has a relatively simple configuration and is preferable in terms of cost.

Using such an electromagnet as a magnetic field generating means,
By using at least one electromagnet as a magnetic field generating means by arranging the electromagnet as a magnetic field generating means by arranging the electromagnet as a magnetic field generating means in a region facing the guide shaft of the carriage and the guide shaft of the carriage, it prevents rattling. In addition, good control of magnetic field generation can be realized.

When one electromagnet is used, the electromagnet is positioned substantially at the center of the area of the carriage facing the guide shaft, that is, the guide of the carriage intersects a line passing through the center of gravity of the carriage and orthogonal to the axis of the guide shaft. The position on the area facing the shaft and the position of the center of gravity of the electromagnet are arranged so that they coincide with each other. When two or more electromagnets are used, they intersect with a line passing through the center of gravity of the carriage and orthogonal to the axis of the guide shaft. Preferably, the electromagnets are arranged symmetrically with respect to a position on a region of the carriage facing the guide shaft.

According to a fourth aspect of the present invention, in the recording apparatus according to the third aspect, the magnetic core of the electromagnet is disposed so that the central axis is orthogonal to the axis of the guide shaft, so that the magnetic field lines are generated when a magnetic field is generated. Since the magnetic field is generated in a direction perpendicular to the axis of the shaft, a magnetic field acts uniformly between the carriage and the guide shaft, so that the sliding portion does not rattle and the carriage is effectively prevented from being shaken. In addition, since the magnetic force lines are generated in a direction perpendicular to the axis of the guide shaft, a magnetic field effectively acts on the guide shaft.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet recording apparatus according to an embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, this ink jet recording apparatus is roughly divided into a recording head 1 for ejecting ink onto recording paper (not shown) and recording an image inside a housing 40.
8, a carriage 10 for moving the recording head 18 in the width direction of the recording paper (not shown), a guide shaft 28 for slidably instructing the carriage 10, and a toothed belt 24 for transmitting rotational power to the carriage 10. The stepping motor 30 of open loop control for rotating the toothed belt 24 is provided outside the motor 40.

The longitudinal dimension of the housing 40 is determined so as to be slightly longer than the width of a recording paper (not shown).
The longitudinal direction is arranged along the width direction of the recording paper.

The recording head 18 has Y (yellow), M
A color ink tank 20 storing three (Magenta) and C (cyan) ink backs and a black ink tank 22 storing B (black) ink are provided, and ink ejection holes corresponding to each color are provided. are doing. This recording head 18 is based on image information input from the outside,
Image recording is performed by ejecting ink from the respective ink ejection holes onto the recording paper conveyed to the opposing positions.

The carriage 10 has a lock lever 16 inside the rear surface of the carriage 10 for fixing the recording head 18, and a locking claw 14 on the upper surface of the carriage 10 has a color ink tank 20 mounted on the recording head 18 and a black ink tank 20. Projections 20 a, 2 provided on the upper surface side of tank 22
By engaging with 2a, the color ink tank 20 and the black ink tank 22 are fixed.

At positions below both sides of the carriage 10,
Each has an opening 10a. This opening 1
A substantially cylindrical guide shaft 28 having an outer diameter slightly smaller than the diameter of the opening 10a of the carrier is inserted through Oa, and slidably supports the carriage 10. The guide shaft 28 is made of a magnetic material SUS303, and is attached to the housing 40 so that the center axis is in the longitudinal direction of the housing 40.

Further, the outside of the rear surface of the carriage 10 is fixed to a part of a toothed belt 24, and the toothed belt 24 is outside the casing 40 via a pulley 26 having teeth formed on the outer peripheral surface. It is connected to the provided stepping motor 30. Therefore, the toothed belt 24 is rotated by the rotation of the stepping motor 30, and the toothed belt 24 is rotated.
The carriage 10 fixed to a part of the toothed belt 2
4 rotates on the guide shaft 28 by rotation.

Further, the electromagnet 1 is located at the center of the area of the carriage 10 facing the guide shaft 28 from above.
2 are provided. The electromagnet 12 has a configuration in which a copper coil is wound around an iron core having a central axis in a direction perpendicular to the axial direction of the guide shaft 28, and as shown in FIG. To the carriage.

The electromagnet may be configured such that an iron core is fitted into a hole provided in the carriage in advance and integrated with the carriage, or resin is injected after the iron core is placed in the carriage mold. Then, the carriage can be integrated with the carriage by insert molding. The latter method, in which the electromagnet is integrated with the carriage by insert molding, has an advantage that it is preferable because the manufacturing is simple and the fitting accuracy is good.

The excitation state of the electromagnet 12 is controlled by an electromagnet control unit 15 provided on the outer surface of the carriage 10.
Magnetic lines of force perpendicular to the axis of the guide shaft 28 are generated. Therefore, the carriage 10 is attracted to the guide shaft 28 by an attraction force acting perpendicularly to the axis of the guide shaft 28, so that the magnetic field acts uniformly and effectively between the carriage 10 and the guide shaft. Becomes Accordingly, the sliding portion between the carriage 10 and the guide shaft does not rattle, and blurring during the movement of the carriage 10 can be effectively suppressed. The electromagnet control unit 15 may be provided on a control board via the flexible cable 29.

Here, with reference to the control block diagram of FIG. 3 and the timing chart of FIG. 4, the movement control of the carriage of the ink jet recording apparatus of the present embodiment will be described. In FIG. 4, section A is a section from when the carriage starts moving to when it reaches the image recording area, section B is a section in which the carriage moves within the image recording area, and section C is an image recording area. From the end of the process to the stop of the carriage.

As shown in FIG. 3, the movement of the carriage is controlled by a CPU for controlling the entire ink jet recording apparatus.
(Central processing unit) 17, a motor driver IC 13 for controlling the drive of the stepping motor 30, and an electromagnet control unit 15 for controlling the on / off of the electromagnet 12 and the magnitude of the current supplied to the electromagnet.

When the print image information is input, the CPU 17 issues an image recording start instruction to the motor driver IC 13 and the electromagnet control unit 15 based on the reference table stored in the ROM 11.

When an instruction to start image recording is issued from the CPU 17, the motor driver IC 13 connects the stepping motor 30 and the power supply 19 to
When the power is turned on to 0, the rotation frequency of the stepping motor 30 is controlled as shown in FIG.

That is, the motor driver IC is set so that the moving speed of the carriage reaches the predetermined image recording speed V when the carriage reaches the section B after the movement starts.
A step 13 gradually increases the rotation frequency of the stepping motor 30 in the section A until the section B is reached, and rotates the stepping motor 30 gradually faster. Thus, A
In the section, the carriage is moved at a constant acceleration.

The motor driver IC 13 keeps the rotation frequency of the stepping motor 30 constant and rotates the stepping motor 30 at a constant rotation speed from when the carriage reaches the section B until it reaches the section C. As a result, in the section B, the carriage 10 moves at the predetermined image recording speed V.

Further, when the carriage reaches the section C,
The motor driver IC 13 gradually lowers the rotation frequency of the stepping motor 30,
Rotate slowly slowly. As a result, in the section C, the carriage 10 is decelerated, and finally stops.

On the other hand, when an image recording start instruction is issued from the CPU 17, the electromagnet control section 15 determines the connection timing between the electromagnet 12 and the power supply 19 and the current applied to the electromagnet 12 as shown in FIG. Control the size.

That is, T before the carriage 10 shifts from section A to section B after the carriage starts moving.
A current of magnitude I ₁ is applied to the electromagnet 12 from ₁ hour to the time T _{2 in} section B where the carriage starts to move at a constant speed, and the carriage 10 and the guide shaft 2
A sliding resistance f ₁ (see FIG. 4 (d)) having a magnitude capable of suppressing overshoot is generated between the sliding resistance f ₁ and the sliding resistance f ₁ .

At time T ₂ , the carriage 10 starts moving at a constant speed V. At this time, the electromagnet controller 15
4 applies a current of magnitude I ₂ to the electromagnet 12 and suppresses a slight vibration of the carriage 10 between the carriage 10 and the guide shaft 28 with a sliding resistance f ₂ (FIG. 4).
(See (d)). Incidentally, towards the sliding resistance f ₂ size of that Osaekome minute vibration, smaller than the size sliding resistance f ₁ of that Osaekome overshoot magnitude I ₂ of current applied at this time the size I smaller than the _first current.

Further, when the carriage 10 reaches the section C, the rotation frequency of the motor is gradually lowered and the carriage 10 starts to be decelerated at a constant rate.
T ₄ but the carriage is stopped from T ₃ hours reaching C section
Until the time is reached, a current of magnitude I ₁ is again applied to the electromagnet 12 to cause a sliding resistance f ₁ (see FIG. 4D) between the carriage 10 and the guide shaft 28.
Thus, the carriage can be stopped smoothly in a short time.

The carriage 10 and the guide shaft 2
The magnitude of the sliding resistance f generated between the electromagnet 12
Are determined according to the magnitude of the magnetic field generated by the electromagnet control unit 15 so that the current values I ₁ and I ₂ applied to the electromagnet 12 are determined in advance so that the required magnitude of the sliding resistance f is obtained.
Thus, a current is applied to the electromagnet 12 at each application timing.

As described above, in synchronization with the control of the moving speed of the carriage by the motor driver IC 13, the electromagnet controller 15 causes the timing at which the sliding resistance is generated between the carriage 10 and the guide shaft 28 and the magnitude of the sliding resistance. By controlling the distance between the carriage 10 and the carriage 10, the carriage 10 can be moved smoothly without blurring such as overshoot and minute vibration.

The carriage 10 and the guide shaft 2
When it is not necessary to generate a sliding resistance between the motor and the motor, the electromagnet may be turned off, so that an unnecessary load is not applied to the motor for moving the carriage. Can be used. In addition, since an electromagnet which is easy to control and is relatively inexpensive is used as the magnetic field generating means, there is an advantage that not only the movement of the carriage can be controlled with high accuracy but also a low-cost ink jet recording apparatus.

In the above-described embodiment, the case where one electromagnet is used has been described. However, as shown in FIG.
The guide shaft 28 may be disposed at a position on the axis 28a of the guide shaft 28 at the same distance L1 from the line P orthogonal to the axis 28a of the E.8 (ie, symmetrically about the line P). Of course, similarly, when three or more electromagnets are used, the axis 28 of the guide shaft 28 passes through the center of gravity G of the carriage 10.
It is good to arrange so that it may become symmetrical about the line P orthogonal to a.

In this embodiment, the electromagnet is disposed above the guide shaft and a magnetic field is applied from above the guide shaft. However, the present invention is not limited to this configuration. It is also possible to arrange so that a magnetic field is applied from the side of the guide shaft, or an electromagnet is arranged below the guide shaft so that the magnetic field is applied from below the guide shaft.

[0056]

As described above, according to the present invention, it is possible to obtain a recording apparatus which can prevent the occurrence of overshoot or minute vibration at the time of moving the carriage with a relatively simple structure and with high accuracy.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing an ink jet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a partially cutaway side view of the carriage 10 shown in FIG.

FIG. 3 is a block diagram of a control system for controlling movement of a carriage.

FIG. 4 is a timing chart of the control system shown in FIG. 3, where (a) shows a control speed of the carriage,
(B) shows the rotation frequency of the stepping motor,
(C) shows the excitation timing of the electromagnet and the magnitude of the current applied to the electromagnet, and (d) shows the timing and magnitude at which sliding resistance occurs between the carriage and the guide shaft.

FIG. 5 is an explanatory top view cut-away view showing another embodiment of the present invention.

FIG. 6 is a graph showing a change in the moving speed of the carriage when the carriage is switched from an accelerated state to a constant speed according to the configuration of the present invention.

FIG. 7 is a graph illustrating a speed variation of the carriage when an overshoot occurs.

FIG. 8 is a graph showing speed fluctuations of the carriage when a minute vibration occurs.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Carriage 10a Opening 12 Electromagnet 13 Motor driver IC 14 Locking claw 15 Electromagnet controller 16 Lock lever 18 Recording head 19 Power supply 20 Color ink tank 20a Projection 22 Black ink tank 24 Belt 26 Pulley 28 Guide shaft 28a Axis 29 Flexible Cable 30 Stepping motor 40 Housing

Claims (4)

[Claims] 1. A guide shaft made of a magnetic material disposed so as to intersect with a feed direction of a recording medium, a magnetic field generating means at a position facing the guide shaft, a recording head mounted, and a guide shaft mounted on the guide shaft. A carriage movably provided; a moving unit for reciprocating the carriage along the guide shaft; and a guide shaft for controlling the strength of a magnetic field generated by the magnetic field generating unit during movement of the carriage. And a sliding resistance adjusting means for adjusting the magnitude of the sliding resistance generated between the carrier and the carrier. 2. The moving means accelerates and moves the carriage to an image recording start position, moves the carriage at a predetermined constant speed in an image recording area, and decelerates the carriage from an image recording end position. Controlling the movement of the carriage so that the sliding adjusting means generates a strong magnetic field by the magnetic field generating means when the moving means switches the moving speed of the carriage from acceleration to the predetermined constant speed. The recording apparatus according to claim 1, wherein a sliding resistance generated between the guide shaft and the carrier is increased. 3. The magnetic field generating means includes one or more electromagnets, and the one or more electromagnets are symmetrical with respect to a center of gravity of the carriage in a region opposed to a guide shaft of the carriage. The recording device according to claim 1, wherein the recording device is disposed. 4. The recording apparatus according to claim 3, wherein the magnetic core of the electromagnet is disposed such that a central axis is orthogonal to an axis of the guide shaft.