JP2005138554A - Recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable carriage of printing paper to be carried out in high resolution even when a low-cost low-resolution encoder is used. <P>SOLUTION: A recorder is provided with a carrying motor 107 for carrying recording form, encoders 116, 117 for detecting a rotational position of the carrying motor and a control part for stopping the motor at a point of time when a specific time shorter than a time from detecting one slit of a slit plate with an encoder for detecting the next slit has elapsed after the encoder detecting one slit of a slit plate 116 for detecting a position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for controlling a printing paper conveyance position using an encoder.

  In printers, it is desired to improve the image quality and lower the operating sound. In particular, in an ink jet recording apparatus with few noise generation sources during recording, a DC motor and a linear encoder are used as drive means for scanning the recording head, thereby realizing low noise.

Conventionally, in a printing apparatus that conveys printing paper using an encoder, the conveyance accuracy of printing paper depends on the resolution of the encoder.
JP 2002-345277 A

  For this reason, in order to improve the printing resolution in the printing paper conveyance direction for higher image quality, a higher resolution encoder must be used, which increases the cost of the apparatus.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to enable printing paper to be conveyed at a high resolution even when an inexpensive low-resolution encoder is used.

  In order to solve the above-described problems and achieve the object, a recording apparatus according to the present invention includes a conveyance motor for conveying a recording sheet, an encoder for detecting the rotational position of the conveyance motor, and the encoder. When a predetermined time shorter than the time from when the encoder detects one slit of the slit plate until the next slit is detected after detecting one slit of the position detecting slit plate, And a control means for stopping the motor.

  In the recording apparatus according to the present invention, the time from when the encoder detects one slit of the slit plate to when the next slit is detected is measured in advance.

  In the recording apparatus according to the invention, the predetermined time is controlled by measuring an elapsed time after the encoder detects one slit of the slit plate with a timer.

  In the recording apparatus according to the present invention, the predetermined time is set when the recording apparatus is activated.

  In the recording apparatus according to the present invention, the predetermined time is set to a half of a time from when the encoder detects one slit of the slit plate until the next slit is detected. And

  According to the present invention, even when an inexpensive low-resolution encoder is used, printing paper can be conveyed with high resolution.

  Hereinafter, an embodiment of the present invention will be described.

  First, an outline of the present embodiment will be described.

  The recording apparatus of the present embodiment includes a transport motor for transporting a recording sheet, an encoder for detecting the rotational position of the transport motor, and the encoder detects one slit of a slit plate for position detection. And a control means for stopping the motor when a predetermined time shorter than the time from when the encoder detects one slit of the slit plate until the next slit is detected. Features.

  In the recording apparatus of the present embodiment, the time from when the encoder detects one slit of the slit plate until the next slit is detected is measured in advance.

  In the recording apparatus of the present embodiment, the predetermined time is controlled by measuring an elapsed time after the encoder detects one slit of the slit plate with a timer.

  In the recording apparatus of the present embodiment, the predetermined time is set when the recording apparatus is activated.

  In the recording apparatus according to the present embodiment, the predetermined time is set to a half of the time from when the encoder detects one slit of the slit plate until the next slit is detected. And

  Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

  This embodiment is an example in which the present invention is applied to a serial ink jet printer equipped with a detachable recording head with an ink tank.

  FIG. 1 is an overall view of a serial ink jet printer. In the figure, 101 is a recording head having an ink tank, and 102 is a carriage on which the recording head 101 is mounted. An optical sensor is mounted on the carriage. When the print head is mounted, the optical sensor is cut off, and the presence or absence of the print head can be detected. A guide shaft 103 is inserted into the bearing portion of the carriage 102 so as to be slidable in the main scanning direction, and both ends of the shaft are fixed to the chassis 114. The power of the drive motor 105, which is a carriage drive means, is transmitted through the belt 104, which is a carriage drive transmission means engaged with the carriage 102, so that the carriage 102 can move in the main scanning direction. Here, the speed of the carriage is managed by detecting and counting the slit of the encoder scale 122 with the encoder sensor 121 mounted on the carriage 102.

  During printing standby, the printing paper 115 is stacked on the paper feed base 106, and the printing paper is fed by the pickup roller 133 at the start of printing. A PE sensor (not shown) is provided at the lower part of the pinch roller 111 in order to control the amount of heading of the printing paper when the paper is fed. In order to convey the fed printing paper, the conveyance roller 110 is rotated via a gear train (motor gear 108, conveyance roller gear 109) as transmission means by the driving force of the sheet conveyance motor 107 which is a DC motor, and a pinch roller The printing paper 115 is conveyed by an appropriate feeding amount by the pinch roller 111 that is pressed against the conveyance roller 110 by a spring (not shown) and rotates in a driven manner. Here, the carry amount is managed by detecting and counting the slits of the code wheel (rotary encoder film) 116 press-fitted into the carry roller 110 with the encoder sensor 117, thereby enabling high-precision feeding. Reference numeral 130 denotes a pickup motor that is driven during paper feeding, and is managed by detecting and counting the code wheel 131 by the encoder sensor 132. By driving this motor, the pickup roller 133 rotates and performs a paper feeding operation.

  FIG. 2 is a control block diagram of the printing apparatus of this embodiment.

  The CPU 201 is an arithmetic unit that performs creation of print data of the printer device, motor drive for print control, print head discharge control, analysis of commands transferred from the host device, various settings by input from the panel, and the like.

  The ROM 202 stores printer control software, various data, font data used for print data, and the like. The control software in the ROM 202 is read by the CPU 201 and executed as a program. Various types of data are used as initial values as they are, while others are expanded in the RAM 203 and processed and used by the CPU 201. As the font data, designated font data is read out by the CPU 201 as needed and expanded in the RAM 203 to be generated as print data. The font data has different capacities because the number and type of font data differ depending on the model. In the printing apparatus according to the present embodiment, the font is Mincho 1 font.

  The RAM 203 develops the result of modifying the font data described above by the designated modification method and uses it as print data.

  Similarly, in the case of image data, the image data read by the CPU 201 is developed on the RAM 203 at a designated print position and used as print data. Further, the RAM 203 is used as a work memory necessary for program execution and a reception buffer as a temporary storage location of input data from the I / F (interface) 204.

  The I / F 204 is connected to a host device (not shown) and receives data such as print data and a print instruction command.

  The I / F of the present embodiment has an electrical specification conforming to IEEE-1284, and not only data from the host but also the printer status is transferred to the host, so that an I / F capable of bidirectional communication is available. It has become. The EEPROM 205 not only stores the setting state of the printer, but also stores the number of printed sheets, the remaining amount of ink, and the like. As the status of the printer, font type, corresponding paper, function items such as automatic power ON / OFF, and the like are stored as information. The motor controller 206 is a printer that performs printing by causing the printer of the present embodiment to scan the print head in the main scanning direction and perform printing by scanning the print head once or a plurality of times. The CPU 201 controls the motor controller 206, and printing is performed using a constant speed region of the motor.

  Another control of the motor controller 206 is control of a conveyance motor which is a motor for moving the paper in the traveling direction. This motor can operate independently of the head scanning motor. In normal printing, the head scanning motor scans once or a plurality of times, and then the conveyance motor controller controls to feed a predetermined amount of paper. Further, in the present embodiment, since the pickup motor for feeding is provided, the pickup motor controller moves the printing paper from the feeding port to a predetermined position where the driving of the feeding motor is transmitted. Transport.

  Reference numeral 207 denotes a print head controller, which is a heat treatment, head maintenance control, and ink amount detection of a print section composed of two heads, a black head having 600 DPI 160 nozzles and a color head composed of 48 nozzles of 1200 DPI Y, M, and C. And so on. The head sensor 213 is in the print head controller 207, and detects the presence or absence of the head by periodically reading the output value of the sensor by the CPU 201. In this embodiment, the electrical specifications are such that when the sensor output is HIGH, the print head is mounted, and when the output value is LOW, the print head is not mounted. Reference numeral 208 denotes an A / D converter in the CPU 201, which has a function of converting to an 8-bit value at about 5 μsec per time. A bus line 209 is a data and address bus for transferring data. The CPU 201 uses the bus line 209 to control each unit from 202 to 207.

  Reference numerals 210 and 211 denote power supply lines to the respective units, and reference numeral 212 denotes a display panel provided in the upper part of the printing apparatus main body. The display panel includes a power key, a resume key for designating recovery, test print, and error recovery, and an LED for displaying data reception and power status.

  FIG. 3 is a schematic diagram for explaining feedback control of the conveyance motor 107 using the speed servo.

  The speed servo is controlled by a method called PID control or classical control, and the procedure will be described below.

  First, the target speed desired to be given to the controlled object is given in the form of an ideal speed profile 301. This is the speed command value at the corresponding time. As time progresses, this speed information changes. Driving is performed by performing additional value control on this ideal speed profile.

  In the speed servo, a method of performing PID calculation for calculating the proportional term P, the integral term I, and the differential term D is common. Based on the information detected by the encoder sensor 304 (corresponding to 117 in FIG. 1), the difference between the encoder speed information obtained by the encoder speed information conversion means 305 and the speed command value obtained by the ideal speed profile 301 is taken, This numerical value is transferred to the PID calculation circuit 302 as a speed error which is insufficient with respect to the target speed, and the energy to be given to the DC motor 303 (conveyance motor 107) at that time is calculated by a method called PID calculation. A coefficient used for the PID calculation is called a gain, and a value optimally adjusted for each table is set in advance and stored in the ROM 202 of FIG. In this embodiment, there are four types of tables: a high-speed table for printing, a low-speed table for printing, a high-speed table for paper feed / discharge, and a low-speed table for paper feed / discharge. The motor driver circuit that has received the result of the PID calculation uses, for example, PWM control, adjusts the current value by changing the duty of the applied voltage, adjusts the energy applied to the DC motor 303, and performs speed control.

  The DC motor that rotates by applying a current value performs physical rotation while being influenced by the disturbance 306, and its output is detected by the encoder sensor 304.

  FIG. 4 is a diagram for explaining the ideal speed profile 301 of FIG. 3 in detail.

  Reference numeral 401 denotes a speed profile, where the vertical axis represents speed and the horizontal axis represents time. Reference numeral 402 denotes an acceleration area, 403 denotes a constant speed area, and 404 denotes a deceleration area. These are the four types of tables described in the present embodiment, which are different in time and speed. Reference numeral 405 denotes a stop preparation area, which is a preparation area for reducing the speed fluctuation up to 404 and smoothly transferring control to the stop area 406. The stop area 406 is provided for four slits by a 1200 DPI encoder (corresponding to the code wheel 116). 405 and 406 have the same configuration in both speed and time even in four different tables. Reference numerals 407, 408, 409, 410, and 411 denote times until the next slit (of the code wheel 116) is detected in the stop area 406. In order to shift the control from 405, the initial speed of 407 is faster than the shift to 408, and as a result, the time is a little shorter, and in order of 408, 409, 410, 411, the ideal time is reached. Approaching.

  In this figure, the target stop position is where the last slit has been detected after 410 hours have elapsed. The position where the time of 412 is controlled by the timer is the stop position between the slits (between the slits). In this embodiment, the motor can be stopped at an intermediate position between the slits by appropriately setting the time 412 controlled by this timer, and the motor stop position control can be performed with a resolution higher than the pitch interval of the encoder slits. Can be performed. In the present embodiment, this time is calculated in advance before driving, and is calculated using 410 times driven in the past.

  The details of this control will be described with reference to the control flowcharts of FIGS.

  In step S501 in FIG. 5, the timer value determination process between slits is started. This process must be performed in advance before the printing paper is transported. In this embodiment, this process is performed for each table during the power-on initial operation. In step S502, motor driving is started with the table specified by the host module, and the motor is driven by the motor control already described until the target driving position is reached. In step S503, the timer starts until the timer start position is reached. If the timer start position is reached, the timer is started in step S504. The timer start position in step S503 is set to a position one slit before the drive target position slit. Until the drive target position is reached in step S505, when the drive target position is detected, the timer is stopped in step S506. In step S507, the value of the timer between slits is determined from the timer value.

  In the present embodiment, a method of controlling at a resolution of 2400 DPI using a 1200 DPI encoder will be described. Since this timer time is measured from the position one slit before the drive target position to the drive target position, the time taken to move one pitch of the 1200 DPI slit is this timer time. Since the 2400 DPI position arrives in half the time of 1200 DPI, a time ½ of this value becomes the timer time between slits. In step S508, the calculated inter-slit timer time is stored in the storage area, and in step S509, a motor stop process is performed. In step S510, the timer value determination process between slits is terminated.

  In step S530, the timer value is actually used to start driving to perform stop control between the slits. In step S531, it is first determined whether there is an inter-slit stop command before driving. The presence / absence of an inter-slit stop command is specified by the driving amount from the host module. If there is an inter-slit stop command, “Yes” is set in the inter-slit stop information in step S532, and if there is no inter-slit stop command, “None” is set in the inter-slit stop information.

  After the information is set, the motor driving is started with the table selected in step S534, and the motor is driven by the already described motor control until the drive target position is detected. Until the drive target position is detected in step S535, when the target position is detected, the control shifts to step S536. If there is no inter-slit stop command in step S536, motor stop processing is performed in step S540, and conveyance motor drive processing is terminated in step S541.

  If there is an inter-slit stop command, the timer value between slits stored in the storage area in step S537 (half the time required to move from one slit to the next slit) is set in the timer, and the timer is set in step S538. Start it. Until the timer expires in step S539, after the time is up, a motor stop process is performed in step S540, and the driving of the transport motor is terminated in step S541. By this control, the conveyance motor can be stopped at the slit of the 1200 DPI encoder and the center of the slit, and as a result, a resolution of 2400 DPI can be obtained.

  The above embodiment includes means (for example, an electrothermal converter, a laser beam, etc.) that generates thermal energy as energy used to cause ink ejection, particularly in the ink jet recording system, and the ink is generated by the thermal energy. By using a system that causes a change in the state of recording, it is possible to achieve higher recording density and higher definition.

  As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recorded information and applying a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface of the liquid, and as a result, bubbles in the liquid (ink) corresponding to the drive signal on a one-to-one basis can be formed.

  By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape, since the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve discharge of a liquid (ink) having particularly excellent responsiveness.

  As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.

  As the configuration of the recording head, in addition to the combination configuration (straight liquid flow path or right-angle liquid flow path) of the discharge port, the liquid path, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the heat acting surface The configurations described in US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which is arranged in a bending region, are also included in the present invention. In addition, Japanese Patent Application Laid-Open No. 59-123670, which discloses a configuration in which a common slot is used as a discharge portion of an electrothermal transducer, or an opening that absorbs a pressure wave of thermal energy is discharged to a plurality of electrothermal transducers A configuration based on Japanese Patent Laid-Open No. 59-138461 disclosing a configuration corresponding to each part may be adopted.

  Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is satisfied by a combination of a plurality of recording heads as disclosed in the above specification. Either a configuration or a configuration as a single recording head formed integrally may be used.

  In addition to the cartridge-type recording head in which the ink tank is integrally provided in the recording head itself described in the above embodiment, it can be electrically connected to the apparatus body by being mounted on the apparatus body. A replaceable chip type recording head that can supply ink from the apparatus main body may be used.

  In addition, it is preferable to add recovery means, preliminary means, and the like for the recording head to the configuration of the recording apparatus described above because the recording operation can be further stabilized. Specific examples thereof include a capping unit for the recording head, a cleaning unit, a pressurizing or sucking unit, an electrothermal converter, a heating element different from this, or a preheating unit using a combination thereof. In addition, it is effective to provide a preliminary ejection mode for performing ejection different from recording in order to perform stable recording.

  Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but the recording head may be integrated or may be a combination of a plurality of colors. An apparatus having at least one of full colors can also be provided.

  In the embodiment described above, the description is made on the assumption that the ink is a liquid, but it may be an ink that is solidified at room temperature or lower, or an ink that is softened or liquefied at room temperature, Alternatively, the ink jet method generally controls the temperature of the ink so that the viscosity of the ink is within a stable discharge range by adjusting the temperature within a range of 30 ° C. or higher and 70 ° C. or lower. It is sufficient if the ink sometimes forms a liquid.

  In addition, it is solidified in an untreated state in order to actively prevent temperature rise by heat energy as energy for changing the state of ink from the solid state to the liquid state, or to prevent ink evaporation. Ink that is liquefied by heating may be used. In any case, by applying heat energy according to the application of thermal energy according to the recording signal, the ink is liquefied and liquid ink is ejected, or when it reaches the recording medium, it already starts to solidify. The present invention can also be applied to the case of using ink having the property of liquefying for the first time.

  In such a case, the ink is held as a liquid or solid in a porous sheet recess or through-hole as described in JP-A-54-56847 or JP-A-60-71260, It is good also as a form which opposes with respect to an electrothermal converter. In the present invention, the most effective one for each of the above-described inks is to execute the above-described film boiling method.

1 is an overall view of an inkjet printer according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a control configuration of a printer. It is a figure of the feedback control of the motor for conveyance using a speed servo. It is a figure explaining an ideal speed profile in detail. 6 is a flowchart illustrating printing paper conveyance control. 6 is a flowchart illustrating printing paper conveyance control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Recording head 102 Carriage 103 Guide shaft 104 Belt 105 Drive motor 106 Paper feed base 107 Paper conveyance motor 108 Motor gear 109 Conveyance roller gear 110 Conveyance roller 111 Pinch roller 114 Chassis 115 Printing paper 116 Rotary encoder film 117 Encoder sensor 121 Encoder sensor 122 Encoder Scale 130 Pickup motor 131 Code wheel 132 Encoder sensor 133 Pickup roller 201 CPU
202 ROM
203 RAM
204 Interface control unit 205 EEPROM
206 Motor Controller 207 Print Head Controller 208 A / D Converter 209 Bus Line 210, 211 Power Supply Line 212 Display Panel 213 Head Sensor 301 Ideal Speed Profile 302 PID Calculation Unit 303 DC Motor 304 Encoder Sensor 305 Encoder Speed Information Conversion Unit 306 Disturbance 401 Speed profile 402 Acceleration area 403 Constant speed area 404 Deceleration area 405 Stop preparation area 406 Stop area 407 to 411 Time until the next slit is detected in 406 Time that is 1/2 of 412 411

Claims (5)

A transport motor for transporting the recording paper;
An encoder for detecting the rotational position of the transport motor;
After the encoder detects one slit of the position detection slit plate, a predetermined time shorter than the time from when the encoder detects one slit of the slit plate until the next slit is detected. Control means for stopping the motor at the time of
A recording apparatus comprising: The recording apparatus according to claim 1, wherein a time from when the encoder detects one slit of the slit plate until the next slit is detected is measured in advance. The recording apparatus according to claim 1, wherein the predetermined time is controlled by measuring an elapsed time after the encoder detects one slit of the slit plate with a timer. The recording apparatus according to claim 1, wherein the predetermined time is set when the recording apparatus is activated. 2. The recording apparatus according to claim 1, wherein the predetermined time is set to a half of a time from when the encoder detects one slit of the slit plate until the next slit is detected. .

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