JPH05197313A - Magnetic printer - Google Patents

Abstract

PURPOSE:To provide a carriage driving mechanism which is used for the printing device such as a printer, which is inexpensive and which can position at high speed and with high precision. CONSTITUTION:The magnetic printer is provided with positioning information recorded on a recording medium 4 formed on a film state, a plate state or a drum state supporting body and an access mechanism reading the positioning information and scanning and positioning to an arbitrary position on the recording medium 4. Furthermore, a composite magnetic head 1 provided with a magnetic gap, other than for latent image formation, to read the positioning information is used. Then, a closed-loop control is carried out by constituting a speed control system sampling the positioning information with the composite magnetic head 1, carrying out detection of position and speed of the magnetic head 1 and feeding back the obtained data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer used as an external output device such as a computer, and more particularly to a carriage drive mechanism used in the printer.

[0002]

2. Description of the Related Art Conventionally, in a printing device used as an external output device such as a computer, for example, a printer,
A mechanism unit that mounts one or more print heads and moves them in the main axis direction is called a carriage mechanism or a spacing mechanism. The motor used for this is called a carriage motor. As a carriage motor, various stepping motors such as PM type and HB type and DC servo motors are applied. In addition to the use of DC servo motors in high-end printers, there is also an example in which a simple encoder is attached to the counter output shaft of a stepping motor to perform closed loop control. Power transmission in the carriage mechanism includes a method using a timing belt, a method using a wire rope, and a method using a feed screw. There is also a drive method using a linear stepping motor that directly drives the carriage. Further, particularly in a magnetic printing apparatus, a magnetic head is used as a print head for forming a magnetic latent image. For example, considering the case of a resolution of 300 DPI, 2500 heads are required to cover the recording width in the width direction of A4 size paper. If these are arranged side by side to form a full line, it is not necessary to scan the head, and extremely high speed recording is possible.
However, the full line head has a problem in that it is difficult to manufacture the head itself and the cost is huge. Therefore, in practice, a method of scanning and recording with a head of several tens to several hundreds of channels is adopted.

[0003]

However, as printers become more sophisticated, naturally, high quality prints are required. Therefore, it is necessary to increase the resolution. When the resolution is further increased as compared with the resolution of 300 DPI which is generally used in page printers and the like at present, high density recording is required also in magnetic latent image formation. High-precision positioning of the carriage is required as the recording density is increased, but the conventional carriage mechanism has a problem that high-precision positioning is difficult.
In order to achieve highly accurate positioning, it is usual to perform closed-loop control using an encoder, but the use of an encoder also has the problem that the cost of the carriage mechanism becomes high. In addition, high speed is required to increase the added value of the printer. As mentioned above, the full line head is difficult to manufacture, so if the method of scanning and recording the head of several tens to several hundreds of channels is used, the conventional carriage mechanism has its performance limit when the stepping motor is used. When a DC motor is used, there is a problem that there is no high speed drive system.

The present invention solves such a problem, and an object thereof is to provide a carriage drive mechanism which is used in a printing apparatus such as a printer, is inexpensive, and can perform high-speed and high-precision positioning. Especially.

[0005]

The magnetic printing device of the present invention comprises a latent image erasing device, a magnetic latent image forming device, a developing device, a transfer device, and a cleaning device, and is a film-shaped, plate-shaped, or drum-shaped magnetic printing device. Position information recorded on a recording medium formed on a support having a circular shape, and an access mechanism for reading the position information and performing scanning positioning at an arbitrary position on the recording medium, and forming the magnetic latent image The apparatus uses a composite magnetic head having a magnetic gap for reading the position information separately from that for forming a latent image, and the position information is sampled by the composite magnetic head to detect the position of the magnetic head. The speed control system is configured to feed back the obtained detection data and perform closed-loop control.

[0006]

EXAMPLES The present invention will be described in detail below based on examples. FIG. 1 is a schematic view of a carriage driving mechanism of a magnetic printing apparatus of the present invention. Here, 1 is a magnetic head that is multi-channeled into several tens to several hundreds of channels, 4 is a magnetic drum, and 5 is a main axis that is the center of rotation of the drum. A motor is built in a carriage 2 on which the magnetic head 1 is mounted. In the present invention, a linear voice coil motor (hereinafter referred to as LVCM) is used as the motor. The LVCM is a kind of linear motor, and has been used recently for head positioning of OA / information equipment, especially a magnetic disk device. The members that make up the motor are the coil, the yoke, the magnet, the back plate, and the linear scale. A magnetic circuit is composed of the yoke, the magnet, and the back plate, and thrust is generated by passing a predetermined current through the coil wound around the yoke.
The thrust causes the carriage to move linearly on the linear scale, but positioning is performed by feedback control using the linear scale as a sensor. In FIG. 1, the carriage reciprocates on the linear scale 3 arranged parallel to the main axis of the drum.

In comparison with this, FIG. 2 is a schematic view of a carriage drive mechanism of a conventional magnetic printing apparatus. A carriage 6 carrying a magnetic head 7 is supported by a slide bearing 9 and reciprocates on a guide shaft 8. At that time, the rotation of the motor 11 is transmitted to the carriage through the timing belt 10. A DC motor is mainly used as the motor, and the rotary encoder 12 is directly connected to the motor shaft.
The encoder output is fed back to the motor control circuit to perform closed loop control for positioning. However, although belt drive is low in cost, stop damping characteristics differ when the carriage is close to the drive motor and far. Also, in order to obtain the positioning accuracy, the tension of the belt has to be considerably strong. The cost of supporting slide bearings is also low, but the friction load is large and the load varies. If this were replaced with ball bearing support, the friction load would be less and the reliability would be higher, but the cost would be higher. When the LVCM is used as in the present invention, there is almost no frictional load, which is a problem in the conventional example, and there is a high thrust, so high speed can be secured. Further, since there is no conversion mechanism, the accuracy of the motor directly becomes the positioning accuracy of the carriage. Furthermore, there is no concern about durability such as belt breakage and wear of the guide shaft.
The cost is almost the same as the structure of belt drive and slide bearing support.

In the carriage drive mechanism of the present invention, rough positioning is performed by the LVCM itself, and high-precision positioning uses the sector servo system which is often used in magnetic disk devices. In the sector servo system, the position information is recorded in several sectors, the position information reproduced from the servo pattern is sampled for each sector, the position of the carriage and the speed are detected, and the obtained detection data is sent to the control system. Feedback is performed to perform closed loop control. The servo system used in the present invention, the configuration of the control system, and the operation of each part will be described in detail below.

FIG. 3 is a conceptual diagram of position information recorded on the recording medium of the magnetic printing apparatus of the present invention.

The position information is recorded in the form of position information A and position information B in the main scanning direction and the sub scanning direction of the carriage, respectively. Recording is performed by a servo writer that incorporates a known laser length measurement system and is capable of highly accurate positioning. Since the data is magnetically recorded on the magnetic drum, the position information cannot be erased unless demagnetized. Select a location for recording that has nothing to do with actual printing. Specifically, in the main scanning direction, recording is performed at the carriage movement limit at the end of the drum, and in the sub scanning direction at a certain position on the circumference of the drum with a sufficient width parallel to the main axis of the drum. The position information is recorded by deciding a specific servo pattern in which various frequencies are combined.

FIG. 4 is a schematic perspective view of a composite magnetic head used for forming a magnetic latent image and reproducing position information. One is for forming a latent image and the other is for reproducing with the spacer 20 in between.
When a recording coil 19 is wound around the recording core 17 and a predetermined current is applied, a leakage magnetic flux is generated from the recording gap 18. Magnetic recording is performed on the recording medium by the leakage magnetic flux to form a magnetic latent image. On the other hand, the structure of the reproducing head is the same as that for forming a latent image, but the reproducing gap 23 is narrower than the recording gap. The leakage flux from the position information magnetically recorded on the recording medium is expanded by the reproduction gap, and the reproduction coil 22
Know the contents of the position information by measuring the induced electromotive force generated in the. Since it is a magnetic printing device, a composite magnetic head as shown in FIG. 4 can be used as the head for reading the position information, and the system can be constructed almost the same as the conventional system without adding complicated and expensive parts.

Next, the structure of the control system and the function of each part will be described. FIG. 5 is a block diagram of a control system for controlling the carriage drive mechanism used in the present invention. LVC
The position information reproduced by the magnetic head 24 mounted on the M25 is sampled by the position information sampler 26, further A / D converted by the A / D converter 27, and sent to the CPU 29. Since the servo pattern used for the position information is known, the CPU detects the position and speed of the carriage from the sent data. The data processed by the CPU is D / A converted by the D / A converter 31, passes through the compensator 32, and is sent to the voice coil motor driver 34. The speed control signal from the voice coil motor driver is added to the LVCM to perform closed loop control. When the sector servo method is used in this way, the acceleration of the carriage is accelerated in an open loop, and the LVCM is controlled so that the carriage movement speed follows a certain reference speed at the time of deceleration, so that high-speed and stable carriage driving can be performed. it can. The sector servo system can realize the main part of the servo system by software, simplifying the circuit,
The flexibility of the system can be increased. Although it depends on the driving method of the carriage, basically, positioning is performed by performing servo by the main scanning and sub-scanning of the carriage. Furthermore, an electromagnet is used for the degaussing device for erasing the magnetic latent image, and the place where the position information is written is de-energized so as not to degauss. Since the LVCM is used in the present invention, there is almost no friction load on the carriage supporting portion, low noise is possible, and the durability of the carriage driving mechanism is also improved. In addition, the device can be made thinner than when a conventional DC motor is used.

In the above embodiment, the case where the recording medium is formed on the drum-shaped support has been described, but the recording medium is formed on the film-shaped or plate-shaped support. May be. Needless to say, the LVCM technology is not limited to the magnetic printing apparatus of the present invention and can be widely applied to printers.

[0014]

As described above, according to the present invention, since the linear voice coil motor and the driving method by the sector servo system are used for the carriage driving mechanism of the printing apparatus such as the printer, the conventional carriage using the rotary encoder. It is cheaper than a drive mechanism and can perform high-speed and high-accuracy positioning. Further, since it is a magnetic printing device, the head for reading servo information can use a composite type magnetic head integrated with the recording head, and can be constructed with almost the same system as the conventional one.

Further, since the linear voice coil motor is used, there is almost no friction load on the carriage supporting portion, low noise is possible, and the durability of the carriage driving mechanism is improved. In addition, the device can be made thinner than when a conventional DC motor is used.

[Brief description of drawings]

FIG. 1 is a schematic view of a carriage drive mechanism of a magnetic printing apparatus according to the present invention.

FIG. 2 is a schematic view of a carriage drive mechanism of a conventional magnetic printing apparatus.

FIG. 3 is a conceptual diagram of position information recorded on a recording medium of the magnetic printing apparatus of the present invention.

FIG. 4 is a schematic perspective view of a composite magnetic head used in the present invention.

FIG. 5 is a configuration diagram of a control system for controlling a carriage driving mechanism used in the present invention.

[Explanation of symbols]

 1 Magnetic Head 2 Carriage 3 Linear Scale 4 Magnetic Drum 5 Spindle 6 Carriage 7 Magnetic Head 8 Guide Shaft 9 Sliding Bearing 10 Timing Belt 11 Motor 12 Rotary Encoder 13 Position Information A 14 Position Information B 15 Magnetic Drum 16 Spindle 17 Recording Core 18 Recording Gap 19 Recording Coil 20 Spacer 21 Reproducing Core 22 Reproducing Coil 23 Reproducing Gap 24 Magnetic Head 25 Linear Voice Coil Motor 26 Position Information Sampler 27 A / D Converter 28 I / O 29 CPU 30 Memory 31 D / A Converter 32 Compensator 33 Switch 34 Voice coil motor driver

Claims (3)

[Claims] 1. A magnetic printing apparatus comprising a latent image erasing device, a magnetic latent image forming device, a developing device, a transfer device, and a cleaning device, and a recording formed on a film-shaped, plate-shaped, or drum-shaped support. A magnetic printing apparatus comprising: position information recorded on a medium; and an access mechanism capable of reading the position information and performing scanning positioning on an arbitrary position on the recording medium. 2. The magnetic printing according to claim 1, wherein the magnetic latent image forming apparatus uses a composite magnetic head provided with a magnetic gap for reading the position information separately from the latent image forming device. apparatus. 3. A closed loop control is performed by constructing a speed control system that samples the position information by the composite magnetic head, detects the position and speed of the magnetic head, and feeds back the detected data. The magnetic printing apparatus according to claim 1, wherein: