JP2007044947A - Recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a drive system for stopping a carriage while preventing noise from occurring during the deceleration of carriage driving when a sliding load is increased in the carriage drive system of an ink-jet recording device. <P>SOLUTION: The ink-jet recording device is composed so that a fixed value is outputted in the direction opposite to the carriage advancing direction instead of utilizing a short brake for decelerating a motor by consuming counter-electromotive force during the deceleration of the carriage driving. A load state of the carriage drive system is judged from a speed command value during the deceleration and an actually driven carriage speed value. The carriage drive system is optimized by changing the fixed value corresponding to the judgement results. Consequently, it is possible to stop the carriage while preventing the noise from occurring during the deceleration. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to carriage drive deceleration and stop control in a recording apparatus.

  2. Description of the Related Art Conventionally, in a serial printer (hereinafter referred to as a conventional example), for example, a DC motor and its control device are used as a drive source for scanning a carriage on which a recording head such as a dot impact method, an ink jet method, or a thermal transfer method is mounted. ing. When a general serial printer receives recording data from an external computer or the like, it starts rotating the motor for driving the carriage, and starts recording when it reaches a certain speed. When data for one line is recorded, the motor is stopped and the paper for one line is fed. Further, if there is recording data, the above operation is repeated to continue recording. Here, the operation of the carriage drive motor (hereinafter referred to as the carriage motor) will be described in detail.

  First, when a recording start command is sent from the computer, the printer controller activates the carriage motor via the motor control device. For example, as shown in FIG. 2, acceleration is gradually performed immediately after startup so as not to generate noise or vibration (A: acceleration region). Then, constant speed control is performed at a predetermined target speed and recording is performed (B: constant speed region). After the end of recording, it is quickly decelerated (C: deceleration area) and stopped. That is, control is performed so as not to disturb the print recording accuracy in the C: constant speed region, so that noises and the like are not generated due to rapid speed fluctuations in the B: acceleration region and C: deceleration region.

  The speed control of the carriage motor as described above is generally performed by a servo system having a PID control loop, and finally is performed by changing the voltage applied to the motor or the duty of PWM.

  Here, description will be made assuming that the motor speed is controlled by controlling the PWM duty. First, the speed error Ve is calculated by subtracting the moving speed of the object to be controlled (here, the carriage) or the rotational speed of the motor detected by the position or speed detecting mechanism such as the encoder from the externally designated speed. Next, for example, an operation amount (here, PWM duty) is calculated according to the following equation.

PWM = Kp × Ve + Ki × ∫Vedt + Kd × (dVe / dt) (1)
Here, Kp: proportional control constant, Ki: integral control constant, and Kd: differential control constant.

  The speed of the carriage is controlled by changing the duty of the PWM applied to the motor driver according to the calculated value.

Utilizing these techniques, the following prior art is a technique for obtaining good speed control performance by changing the parameter of the PID term in the compensator from the comparison of the detected drive speed with respect to the change of the load condition. There is.
JP-A-5-080856

  With the recent demand for higher image quality, the number of ink droplets ejected from the recording head has increased in a short time, and the number of ink droplets ejected from the recording head has been reduced. Along with this, the amount of mist-like ink droplets floating in the recording apparatus main body is also increasing. For this reason, mist-like ink droplets adhere to the guide shaft, and the deterioration of load conditions in the carriage drive system such as the guide shaft and the bearing is further increased.

  In such a situation, the conventional technology attempts to stabilize the followability by speed control with respect to the command value, but it is difficult to determine parameters suitable for individual environments and load conditions. Furthermore, in the deceleration area, instead of using a short brake that consumes counter electromotive force and decelerates the motor in order to quickly decelerate and stop, a drive command value output that is fixed in the direction opposite to the carriage traveling direction is output. It is carried out.

  Furthermore, when the change in the load condition is large, it is difficult to decelerate and stop at a fixed time or distance with this fixed drive command value output, leading to a significant reduction in product performance.

  The present invention has been made in view of the above problems, and an object thereof is to provide a recording apparatus capable of realizing a recording operation by reciprocation of a carriage without deteriorating driving performance.

  To achieve the above object, the present invention provides a recording apparatus for performing recording by reciprocating a carriage having a recording head along a guide shaft, and detecting means for detecting carriage position or velocity information; A setting source for setting a drive command value for driving the motor, a change unit for changing the drive command value, and an output unit for outputting a fixed drive command value during deceleration driving. And the fixed drive command value is changed according to a load state.

  According to the present invention, with a simple configuration, it is possible to perform a stable deceleration operation of the carriage in response to a change in the load state in the carriage driving system, and a recording operation by reciprocating the carriage without deteriorating the driving performance. Can be realized.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  The present embodiment relates to carriage driving in an ink jet recording apparatus.

  First, an ink jet recording apparatus according to an embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a diagram illustrating a configuration of an ink jet recording apparatus according to an embodiment. In FIG. 1, 1 is a recording head, 5 is a carriage, and the recording head 1 is mounted. The recording head 1 may use thermal energy, or has a form in which droplets of recording liquid are formed using mechanical energy to form an image on a recording medium.

  The recording head 1 includes, for example, a plurality of recording elements (for example, Y (yellow) head, M (magenta) head, C (cyan) head, Bk (black)) corresponding to inks of different colors. These inks of each color are supplied by connecting the main tank 7 and the recording head 1 through a tube system flow path.

  The carriage 20 is moved by the belt 20 and the carriage motor 5 from a predetermined position in the main scanning direction in the direction of arrows A1-A2 in the drawing, thereby starting recording on the recording medium.

  Next, when the recording in the main scanning direction is completed, the carriage 5 is returned to a predetermined position in the main scanning direction (a fixed position before the recording in the main scanning direction is started), and the conveying roller is driven by the conveying motor 13. The recording medium is conveyed by a predetermined amount in the sub-scanning direction (the arrow B direction in the figure). Thereafter, as described above again, the timing belt 17 and the carriage motor 11 cause the carriage 5 to move from a predetermined position in the main scanning direction in the direction of the arrow A1-A2 in the drawing, so that images, characters, etc. on the recording medium are displayed. Recording is performed.

  By repeating the above-described operation, when recording for one sheet of recording medium is completed, the recording medium is discharged and recording for one sheet is completed.

  Next, the procedure of the entire recording operation of the present embodiment will be described focusing on the carriage movement control.

  FIG. 4 is a flowchart showing a schematic procedure of this recording operation.

  First, when a recording start command is sent from a host computer or the like connected to the recording apparatus via the external I / F, the CPU determines whether or not a carriage initialization process is necessary (S1). If there is, an initialization process is performed (S2).

  One of the initialization processes is a process for moving the carriage to the home position. In the case of the present embodiment, the current position of the carriage is set to a value exceeding the maximum distance that the carriage can move, and the arrival position is set to 0, for example. After setting the arrival position, feedback control is performed to move the carriage. As a result, the carriage moves toward the recovery unit, but before reaching the set arrival position, the carriage contacts the side surface of the main body and is prevented from moving. Accordingly, the encoder sensor detects that the position of the carriage does not change, and the CPU recognizes that the carriage is in a stopped state accordingly. When this stop state is recognized for a predetermined number of control timings, it is recognized that the carriage has contacted the side surface of the main body, and this position is set as the carriage home position. In this embodiment, the home position is set to 100, for example, and after this setting, the position of the carriage is detected as needed based on detection signals detected by the encoder sensor and the linear scale as the carriage moves.

  In this way, when an initialization process such as power-on is necessary, the initialization process is performed. Thereafter, it is determined whether or not the recording head mounted on the carriage is in the capping state covered with the cap of the recovery unit (S3). If it is in the capping state, a cap OPEN process for removing the cap from the recording head is performed (S4). The cap OPEN state is confirmed.

  Further, in the transport unit for transporting the recording paper shown in FIG. 1, the fed recording paper is sandwiched between the transport roller and the pinch roller, and the recording head scans the platen by the rotation of the transport roller. Is intermittently conveyed in synchronization with During this conveyance, recording is performed on the paper by the ink ejection as the recording head scans. In this conveyance, the sheet is discharged by the rotation of the conveyance roller.

  Referring to FIG. 4 again, for the recording sheet conveyed as described above, it is determined whether or not there is the sheet in the conveyance unit (S5). If it is determined that there is no sheet, the conveyance motor is driven to rotate the conveyance roller and convey the sheet to the recording start position (S6).

  Next, the CPU sets a position where the carriage should reach according to the print data (S7), and starts driving for moving the carriage based on feedback control (S8). In this carriage movement control, feedback control is performed at a cycle of 2 msec.

  When the carriage starts to move and the carriage reaches the recording start position, a recording signal is sent to the recording head mounted on the carriage, whereby ink is ejected from the ejection port of the recording head and recording is started. The Further, the carriage is moved and ink is ejected from the print head while printing is continued until the carriage reaches the set arrival position. When the carriage reaches the set arrival position (S9), when printing by one scan of the recording head is completed, the CPU sets the arrival position where the paper should reach according to the print data (S10), and feedback control Based on the above, the driving of the conveyance roller for moving the paper is started (S11). When the paper reaches the set arrival position (S12), the carriage arrival position is set again, and the carriage is moved by feedback control. This process is repeated until a recording end command is received (S13). When a recording end command is sent from the host, the conveying roller is rotated by a predetermined amount to discharge the paper (S14), and the series of recording operations is completed.

  Next, the carriage motor in the recording apparatus having the above-described configuration or carriage movement control by driving the carriage motor will be described.

  In this embodiment, the scanning speed and position of the carriage 5 are recorded with slits at a recording pitch density corresponding to a linear scale 19 (for example, 150 dots / inch (dpi) or 300 dpi) extending in the scanning direction of the carriage 5. And this slit is detected by the encoder sensor 21 mounted on the carriage 5.

  The movement of the carriage is controlled by feedback control that controls the motor in accordance with the error between the feedback value and the command speed value. Here, the command speed is a speed that should be originally achieved at the timing when the speed of the carriage is detected.

  Carriage control is classified into speed control for performing control while paying attention to speed and position control for performing control while paying attention to position. In the ink jet recording operation of this embodiment, since the recording is performed by ejecting ink from the recording head onto the paper while scanning the recording head, the above speed control or position control is appropriately performed and the control is performed. Accordingly, it is necessary to accurately deposit ink droplets at desired positions on the paper by appropriately determining the ink ejection timing based on the above. Such ink ejection is often performed in a constant speed region and an acceleration region in carriage movement. Accordingly, in the acceleration area and the constant speed area of the carriage, control focusing on the speed is performed so that the carriage moves following a predetermined command speed. In the deceleration region, the carriage movement is controlled by paying attention to the position so that the carriage can stop at a predetermined position.

  FIG. 3 is a block diagram showing the configuration of feedback according to the present embodiment. Specifically, the carriage drive mechanism and the motor driver 104 which is the drive circuit of the present embodiment, and the carriage of the encoder sensor 21, etc. It is constituted by a movement detection mechanism.

  Next, a method for updating a fixed drive command value during the deceleration operation of the carriage drive system, which is a characteristic part of the present embodiment, will be described.

  Normally, when performing feedback control of the carriage, a drive command value is calculated so as to follow the command speed during deceleration driving, and the speed is gradually decreased and stopped. However, since the command speed and the drive speed of the carriage cross each other and abnormal noise may be generated when the drive command value is changed, a short brake is used, the unidirectional output of the drive command value and the short brake ON / OFF Control is being used. The present embodiment is a more effective control method in the ON / OFF control method using this short brake.

  In order to realize the deceleration and stop operation of the carriage in a shorter time and a shorter distance, instead of using a short brake, a drive command value is output as an appropriate fixed value in the direction opposite to the carriage traveling direction. It is more effective to stop by a short brake that uses the back-up of the motor than to stop by inertia, and it is more effective than this short brake to reverse energization (the direction opposite to the traveling direction) Drive command value output).

  This drive command value output is handled as a fixed value in the present embodiment. This is only to use the ON / OFF control method of the short brake more effectively. The drive command value in the present embodiment refers to the operation amount (PWM duty) described in the background art.

  Furthermore, this fixed drive command output value is updated according to the load state.

  The state A in FIG. 5 is a state in which the load increases and it is relatively easy to perform a deceleration operation. Therefore, in FIG. 6, the drive command output value is changed from the normal calculated value to the A ′ value. Similarly, the state of B in FIG. 5 is a state in which the load is reduced and it is difficult to perform the deceleration operation, so in FIG. 6, the drive command output value is changed from the normal calculated value to the B ′ value. As a result, it is possible to realize driving following the command speed of the solid line portion in FIG.

  Next, this update determination will be described.

  First, it is desirable to perform this update timing at the time of starting or when a certain number of recording operations are performed, rather than constantly updating.

  In this embodiment, the initialization operation of S2 in FIG. 4 is performed.

  The process will be described with reference to FIG. When the carriage speed is decreased according to the speed command value after the start of the carriage drive deceleration operation, the drive command value is gradually decreased, and then a fixed value reverse energization (S1) is performed.

  During this reverse energization, it is monitored whether or not the command speed and the carriage drive speed intersect (S2), and after the carriage stop determination (S3), the specified number of times or more (in this embodiment, two or more times). ) When intersecting (S4), this value is updated (S5) and used from the next carriage drive.

  That is, this determination criterion is determined by following the actual carriage drive speed value with respect to the speed command value. When the carriage drive speed value intersects with the speed command value, this fixed drive command output value can be made smaller. When the carriage drive speed value does not intersect with the speed command value, this fixed drive command output It is possible to increase the value.

  The present invention relates to a recording apparatus such as a printer, and more particularly to a recording apparatus including a carriage that performs recording by a recording head mounted while moving along a guide shaft. The present invention is applicable to a general printing apparatus, a copying machine, a facsimile having a communication system, a word processor having a printing unit, and an industrial apparatus combined with various processing apparatuses. can do.

It is a figure which shows the structure of the recording device based on this invention. FIG. 6 is a diagram illustrating a carriage driving state in a recording operation of the recording apparatus according to the invention. It is a block diagram which shows the structure of the feedback control in the recording device which concerns on this invention. 6 is a flowchart showing a schematic procedure of a recording operation of the recording apparatus according to the present invention. It is a figure which shows the drive speed value in each load state of the recording device which concerns on this invention. It is a figure which shows the drive command value in each load state of the recording device which concerns on this invention. It is a flowchart which shows the fixed value update determination in the recording device which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head 2 Platen 3 Guide shaft 4 Guide rail 5 Carriage 6 Head cartridge 7 Main tank 8 Joint part 9 Tube 10 Head cap 11 Carriage drive mechanism 12 Sheet supply part 13 Conveyance motor 14 Recovery unit 15 Pinch roller 16 Conveyance roller 17 Timing belt DESCRIPTION OF SYMBOLS 19 Linear scale 20 Linear wheel 21 Encoder sensor 100 Command value generator 101 Command speed 102 PID compensator 103 PWM controller 104 Motor driver 105 Position detector 106 Speed detector 107 PWM command value 108 Data holder 109 Control constant calculator

Claims (1)

In a recording apparatus that performs recording by reciprocating a carriage mounted with a recording head along a guide axis,
Detection means for detecting carriage position or speed information, a motor as a drive source of the carriage, setting means for setting a drive command value for driving the motor, and a change means for the drive command value; An output means for outputting a fixed drive command value during deceleration driving, wherein the fixed drive command value is changed according to the state of the load.

Images