JP2006224559A - Ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent positional shift of a carriage by performing feedback control of a pulse motor for driving a carriage. <P>SOLUTION: The ink jet printer comprises a pulse motor 3 for driving reciprocal scanning operation of a carriage, a scale arranged in parallel with the reciprocal scanning direction of the carriage, an encoder 4 for reading the scale arranged on the carriage, a counter 5 for detecting the position of te carriage based on the count of output pulses from the encoder, a section 6 for determining the difference between the target stop positions 1 at the opposite ends of reciprocal scanning of the carriage and the actual position thereof, and a pulse motor control section 2 for regulating the next target stop position of the carriage depending on the difference. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing apparatus such as a printer, and more particularly to an ink jet printer in which an ink jet head is mounted on a carriage and printing is performed on a recording sheet by reciprocating scanning of the carriage.

  In an ink jet printer that performs printing while reciprocating a carriage on which a print head is mounted, conventionally, the carriage reciprocating scan is driven by a DC motor. Since there is no fixed relationship between the voltage / current applied to the DC motor and, as a result, the amount of movement of the carriage driven by the rotation of the DC motor due to variations in motor characteristics, feedback control must be performed. . For example, a scale installed parallel to the reciprocating scanning direction of a carriage driven by a DC motor is read by an encoder, and the carriage position information is fed back to the DC motor, so that the carriage movement target position and the actual carriage position can be A servo control method for correcting the deviation has been used.

  However, this method is costly and requires a large number of multipliers / dividers for servo control, which complicates the structure of the control unit and takes time and effort to find an optimal control parameter group.

Therefore, in some cases, an inexpensive pulse motor is used instead of the DC motor for driving the carriage (see, for example, Patent Document 1). In a pulse motor, there is always a fixed relationship between the number of pulses applied to the pulse motor and the resulting amount of rotation of the pulse motor, and the amount of movement of the carriage driven by the pulse motor. Even in open loop control without performing accurate feedback control, the carriage can be accurately moved to the target position. In addition, by using open loop control, a circuit for feedback is not necessary, and manufacturing cost can be suppressed and control can be simplified.
JP 5-85005

  When the pulse motor is controlled by open loop control, the stop position at the folding of both ends of the carriage reciprocating scan may deviate from the stop target position due to the load of the mechanism for driving the carriage. In this case, the deviation accumulates as the reciprocating scanning is repeated, and there is a possibility that the printing operation may eventually become impossible.

  In an ink jet printer according to the present invention, a carriage mounted with one or a plurality of ink jet heads and configured to reciprocately scan a recording paper. Drive means for driving a scanning operation, detection means for detecting a deviation between a target stop position and an actual stop position at both ends of reciprocation of the carriage, and feedback of the deviation detected by the detection means to the drive means It has the correction means to do.

  In the present invention, the correction means corrects a next target stop position based on a deviation amount of a current stop position of the carriage.

  Furthermore, in the present invention, the detection means includes a scale installed in parallel with the reciprocating scanning direction of the carriage, an encoder mounted on the carriage to read the scale, and counts pulse outputs from the encoder to count the carriage. The present invention is characterized by comprising counting means for detecting the current position of the recording medium and difference generating means for generating a difference between the output of the counting means and the stop target position of the carriage.

  According to the present invention, when the carriage position information from the encoder unit of the carriage is fed back to the motor control unit, it can be configured by only a counting means such as a counter and a difference generation unit such as a subtractor. It is no longer necessary to install a complicated signal processing unit using multiple multipliers and dividers for feedback from the encoder unit to the motor drive unit, as in the case of servo control, and control parameters are set for the feedback. Therefore, there is no need to search for an optimal combination of control parameters for servo control, and the carriage can be reciprocated with easy control.

  Since the carriage movement control is facilitated, the carriage movement control circuit and the control program can be simplified.

  By simplifying the structure, the manufacturing cost can be kept low.

  Further, by performing feedback control, it is possible to prevent the carriage displacement from accumulating due to the load of the carriage driving unit and the like as printing is continued as in the case of open-loop control of the pulse motor.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS. FIG. 2 shows the configuration of an ink jet printer according to the present invention. FIG. 1 shows a basic configuration around a carriage drive pulse motor control unit of an ink jet printer according to the present invention.

  In FIG. 2, illustration and description of a paper conveyance system, an ink supply system to the head, and the like that are not directly related to the characteristic part of the embodiment of the present invention are omitted.

  In the ink jet printer of FIG. 2, a pulse motor 13 is installed at the end of the support 15, and is fixed to the end of the support 15 through a motor pulley 7 and a transmission belt 8 installed on the shaft of the pulse motor 13. The rotation of the pulse motor 13 is transmitted to the two-stage pulley 14 that has been made. A driven pulley 13 is rotatably installed at the end of the support 15 opposite to the two-stage pulley 14, and rotation is transmitted between the two-stage pulley 14 and the driven pulley 12 through a carriage drive belt 17. . A carriage 11 is fixed to the carriage drive belt 17, and the carriage 11 can move left and right on the platen 16 in accordance with the movement of the carriage belt. A print head 18 is installed on the carriage 11 so as to face the platen 16. Between both ends on the support 15, the scale 9 is installed in parallel with the moving direction of the carriage 11. An encoder 10 is installed on the carriage 11 so as to be close to the scale 9, and the encoder 10 optically reads the scale according to the movement of the carriage 11 to generate a pulse signal.

  Based on the configuration of FIG. 2, the periphery of the pulse motor control unit of FIG. 1 will be described. In the configuration of FIG. 1, a carriage stop target position 1 is given by a program or the like. The stop target position 1 is given to the pulse motor control unit 2, which generates a pulse motor driving pulse and supplies it to the carriage driving pulse motor 3. The pulse motor 3 corresponds to the pulse motor 13 of FIG. The carriage moves according to the rotation of the pulse motor 3, and a pulse obtained by reading the scale 9 is generated from the encoder 4 installed on the carriage. The encoder 4 corresponds to the encoder 10 of FIG. The current position of the carriage is detected by counting the pulses output from the encoder 4 with the counter 5. A difference between the stop target position 1 and the current position of the carriage output from the counter 5 is calculated by the difference generator 6 and the difference is fed back to the pulse motor controller.

  Hereinafter, the operation of such a configuration will be described.

  First, it is assumed that the carriage 11 is at the end of the support 15 close to either the two-stage pulley 14 or the driven pulley 12. Next, a stop target position 1 designating the other end of the support 15 for printing is given by the program. A pulse corresponding to the amount of movement from the current position of the carriage to the target stop position 1 is given from the pulse motor control unit 2 to the pulse motor 3 (or pulse motor 13). The pulse motor 13 is rotated by the given pulse, and the carriage 11 is driven by driving the carriage drive belt 17 through the drive belt 8 and the two-stage pulley 14. The encoder 4 (or encoder 10) reads the scale 9 according to the movement of the carriage and outputs a pulse corresponding to the amount of movement. The current position of the carriage 11 can be detected by always counting the pulses output from the encoder 4 with the counter 5. When the carriage 11 moves to the end of the support 15 according to the stop target position and stops, the difference generator 6 calculates the difference between the current carriage position of the output of the counter 5 and the stop target position 1 at that time. . The difference output from the difference generator 6 is input to the pulse motor controller. If the difference is not 0, when a new stop target position 1 for the next carriage movement is set, the pulse motor control unit 2 calculates a value obtained by correcting the new stop target position 1 with the difference. A pulse motor driving pulse is generated as the target stop position. The above operation is repeated every time the carriage is scanned and stopped. Thereby, it is possible to prevent the deviation between the target stop position of the carriage and the actual stop position from being accumulated every scanning.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various improvement and change are possible in the range which does not deviate from the meaning.

It is a block diagram which shows the structure of this invention. It is a figure which shows embodiment of this invention.

Explanation of symbols

1 Carriage stop target position 2 Pulse motor controller 3 Pulse motor 4 Encoder 5 Counter 6 Difference generator 7 Motor pulley 8 Transmission belt 9 Scale 10 Encoder 11 Carriage 12 Driven pulley 13 Pulse motor 14 Two-stage pulley 15 Support 16 Platen 17 Carriage Drive belt 18 Print head

Claims (3)

An inkjet printer having one or a plurality of inkjet heads and a carriage that carries the inkjet head and performs a reciprocating scanning operation,
Driving means for driving the carriage reciprocating scanning operation by a pulse motor, detection means for detecting a deviation between the target stop position and the actual stop position at both ends of the carriage reciprocation, and deviation detected by the detection means An ink jet printer comprising correction means for feeding back the amount to the driving means.   2. The ink jet printer according to claim 1, wherein the correction unit corrects a next target stop position based on a deviation amount of a current stop position of the carriage.   The detecting means detects a current position of the carriage by counting a scale installed parallel to the reciprocating scanning direction of the carriage, an encoder mounted on the carriage and reading the scale, and counting pulse outputs from the encoder. 2. The ink jet printer according to claim 1, further comprising: a counting unit configured to perform a difference generation unit configured to generate a difference between an output of the counting unit and a target stop position of the carriage.

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