JP3500192B2 - Serial printer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer which reciprocates a carriage in the axial direction of a platen by a pulse motor to perform printing , and more particularly to a technique for positioning a recording head to a home position.

[0002]

2. Description of the Related Art In a serial printer that executes printing while moving a carriage in the platen axis direction by a motor to move a recording head mounted on the carriage to a printing position, in order to improve printing quality, a recording head is used. It is necessary to accurately detect the reference position of. For this reason,
Position detection means is arranged at the reference position and the carriage is set at the reference position. However, since the detection means itself and the mounting position of this require high accuracy, the cost is increased, In addition to the problem of complicating the manufacturing process, there is a problem that accuracy deteriorates due to long-term use. In order to solve such a problem, a damper member which comes into contact with the carriage when the recording head reaches the reference position is provided on the base body, and the carriage is brought into contact with the base member to stop the carriage. A home position setting device has been proposed in which the home position is set to a position moved to the print area side by the number of steps (Japanese Patent Laid-Open No. 53-143130). According to this, although the home position detecting means can be dispensed with, the damper member may be elastically deformed due to the collision with the carriage and the accumulated energy may push the carriage back toward the printing area side. Since the amount is irregular, there is a problem in that the home position varies and the print quality is degraded in high-density printing.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is a serial for accurately positioning a recording head with a position determined by a damper member as a home position. Puri
It is to provide a printer.

[0004]

In order to solve such a problem, according to the present invention, a carriage on which a recording head is mounted is connected to the carriage via a transmission means, and the carriage is moved in parallel with a platen. An electric motor to
A damper member that comes into contact with the carriage when the recording head mounted on the carriage moves to a predetermined position; and a position detection unit that detects the position of the recording head,
Contact determining means for detecting that the output level of the signal from the position detecting means maintains a constant state for a predetermined time in the state where the carriage is moved to the home position side, and outputting a signal, by the signal from the abutment judgment means, before Symbol motor gradually decreases the torque of bets state where the carriage is in contact with the damper member
A braking drive means for maintaining the luck and stopping the carriage is provided, and the position of the carriage stopped by the braking drive means is set to the home position.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 1 is a carriage on which a recording head 2 such as an impact wire recording head, an ink jet recording head, a thermal transfer recording head is mounted, and a platen 3 The guide member 4 is provided so as to be reciprocable in parallel with the axial direction of the. A motor 5 drives the carriage 1, and is connected to the carriage 1 via a timing belt 7 that is hung between the idle roller 6 provided at the other end. The idle roller 6 is provided with a rotary encoder 7 which constitutes an encoder for detecting the position of the recording head 2, and a code detector 8 which is close to the encoder 7 for detecting the code of the encoder 7. There is.

Reference numeral 9 denotes a damper member made of an elastic material such as rubber fixed to a base (not shown) which does not damage the carriage 1 even when the carriage 1 collides with the carriage 1. When the recording head 2 reaches the reference position, the carriage member is moved. The position is set so that 1 contacts.

A carriage control means 10 accelerates the motor 5 at a predetermined acceleration to a printable speed on the basis of speed profile data stored in advance, and then holds the predetermined speed to fix the carriage 1. 1 to run at high speed and then stop while decelerating at a predetermined deceleration
In addition to having a function of controlling a series of movements of the carriage 1 necessary for printing a line, the motor 5 is configured to be driven based on a signal from a home position setting device 11 described later.

Reference numeral 11 denotes the above-mentioned home position setting device, and reference numeral 12 in the drawing denotes a contact determining means, which outputs a signal from the code board detector 8 when the carriage 1 is moving to the home position side. The signal is output by detecting that the output does not fluctuate for a period longer than the signal output during normal traveling. Reference numeral 13 denotes a braking drive means, which is a storage means 1 to be described later when a signal is input from the contact determination means 12.
4, the duty of the drive signal supplied to the pulse motor 5 via the carriage control means 10 is gradually reduced based on the data stored in 4. Reference numeral 14 denotes the above-mentioned storage means, and the duty is set every predetermined period ΔT as shown in FIG. 2, and the value gradually decreases, and finally the damper member 9 is elastically deformed. It is configured to store a duty value with which the carriage 1 can be brought into contact with the damper member 9 without being pushed.

In this embodiment, when the power is turned on, the carriage control means 10 moves the carriage 1 driven by the pulse motor 5 toward the home position (region I in FIG. 3). By this movement, a signal is output from the code plate detector 8 which constitutes the encoder. When the recording head 2 reaches the home position when it moves a predetermined distance in this way, the carriage 1 contacts the damper member 9.

At the beginning of contact, the torque of the motor 5 overcomes the elastic force of the damper member 9, so the damper member 9
Although it undergoes a slight elastic deformation, when it further moves to some extent (T0) in this state, the movement is stopped and the signal from the code plate detector 8 stops changing.

The signal from the code board detector 8 has a predetermined time Δ
t, for example 2 msec is contact-size maintained at that level
When the setting means 12 detects and outputs a signal, the braking drive means 13 sequentially reads the data defining the duty stored in the storage means 14 at a constant cycle and outputs the data to the carriage control means 10.

As a result, the drive energy supplied to the motor 5 gradually decreases, and the drive torque of the motor 5 decreases with time. In this process, due to the collision of the carriage 1, the elastic force accumulated in the damper member 9 is overcome, and finally the carriage 1 starts moving in the opposite direction (region II in FIG. 3). Then, the code board detector 6 detects the position at the time when the duty of the drive signal is reduced to such an extent that the damper member 9 cannot be elastically deformed, and this position is set to the home position.

Of course, even at this time, the motor 5
Does not elastically deform the damper member 9, but generates a torque for moving the carriage 1 to the damper member 9 side, and therefore the recording head 2 is damped regardless of the action of some external force. will be resting position determined mechanically as the home position by parts material 9.

When a print command is input to the carriage control means 10 in this state, the carriage control means 5 moves the carriage 1 at a speed suitable for printing, and print data is printed by the recording head 2 by the head drive means (not shown). Printed on P.

In the above embodiment, the duty of the drive signal for setting the home position is stored in another storage means, but in another storage means, for example, the profile data storage means of the carriage control means. It is obvious that the same effect can be obtained even when stored.

[0016]

Further, although in the above embodiment are to detect the position of the carriage using a rotary code plate, with disposing the code disc in the moving direction of the carriage, provided with a code reading means on the carriage It is obvious that the same effect can be obtained even when applied to the one using the linear encoder.

[0018]

As described above, according to the present invention,
Without the need for home position detecting means, and eliminating the error caused by the repulsion by the damper member ,
Accurately stop the recording head at the home position
It is possible to make.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a structure of a storage unit that stores drive pulse data supplied to a pulse motor when the recording head is positioned at a home position.

FIG. 3 is a waveform chart showing the operation of the above apparatus. .

[Explanation of symbols]

1 carriage 2 recording head 5 motor 7 rotary code board 8 Code board detector 9 Damper member 11 Home position setting device

Claims (2)

(57) [Claims] 1. A carriage on which a recording head is mounted, an electric motor which is connected to the carriage via a transmission means and moves the carriage in parallel to a platen, and a recording head mounted on the carriage has moved to a predetermined position. When the damper member is in contact with the carriage, the position detecting means detects the position of the recording head, and the carriage is moved to the home position side, the output level of the signal from the position detecting means is predetermined. time, a contact determination unit for outputting a detection to a signal that maintains a constant state by the signal from the abutment judgment means gradually decreases the torque before Symbol motor, the carriage before
Keep the torque in contact with the damper member
And a braking drive means for stopping said carriage, serial printer to position the home position of the carriage is stopped by the brake driving unit. 2. The braking drive means includes a storage means that stores data for gradually reducing the drive duty of the electric motor to the extent that the damper member is not deformed when the carriage comes into contact with the damper member. The serial printer according to claim 1, further comprising: