JP2009125993A - Recording device and recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording device which is capable of suppressing the deterioration of a recorded image, even when the output period of the output pulse of an encoder is shortened and a short period PTS (recording head driving timing signal) is outputted and to provide a recording method. <P>SOLUTION: The recording device 1 for recording on a recording medium P, while moving a recording head 8 in a main scanning direction includes: a recording head driving timing signal output means 14 which controls the output timing of a recording head driving signal driving the recording head in accordance with the movement in the main scanning direction of the recording head 8; and a PTS period determining means (CPU 15) which determines whether or not the period of a PTS is shorter than a predetermined period. When the period of the PTS is shorter than the predetermined period, the moving speed in the main scanning direction of the recording head 8 is reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a recording apparatus and a recording method.

  Ink jet printers perform recording by ejecting ink droplets onto predetermined locations of recording paper while moving the recording head in the main scanning direction with respect to the recording medium. The moving position, moving speed, etc. of the recording head in the main scanning direction are detected by a so-called optical encoder provided with a code plate in which a large number of light shielding parts and light transmitting parts are alternately arranged along the main scanning direction. Based on the output pulse from the encoder, a PTS (printing head drive timing signal / PTS: Print Timing Signal) for controlling the ejection timing of the ink droplets is output. In response to the output of the PTS, that is, using the PTS as a trigger, a recording head driving signal for controlling the ink droplet discharging operation of the recording head is output, and the ink droplet is discharged by the recording head driving signal. (See Patent Documents 1 and 2).

JP 2001-150705 A JP 2007-98820 A

  However, when dirt such as ink mist adheres to the light transmission part of the code board, the cycle of the output pulse corresponding to the light transmission part to which dirt has adhered becomes shorter than when no dirt adheres. In some cases, the PTS may be output in a short cycle corresponding to the short cycle pulse. In addition, the PTS may be output in a short period even when the moving speed of the recording head becomes unstable during the recording operation for ejecting ink droplets and the recording head moves at a speed faster than a predetermined speed. .

  When the PTS is output in such a short cycle, the next operation is performed while the recording head drive signal output using the previous PTS as a trigger is output, that is, while the recording head is performing the ink droplet ejection operation. May be output as a trigger for outputting the recording head drive signal. In such a case, since the recording head drive signal cannot be output in response to the next PTS, there is a problem in that the recording head drive signal corresponding to the next PTS is not output and the print image is deteriorated. .

  Therefore, the present invention provides a recording apparatus and a recording method capable of suppressing deterioration of a recorded image even when the output period of an output pulse of an encoder is shortened and PTS is output in a short period. Objective.

  In order to solve the above problems, the present invention drives a recording head corresponding to the movement of the recording head in the main scanning direction in a recording apparatus that records on the recording medium while moving the recording head in the main scanning direction. PTS output means for controlling the output timing of the recording head drive signal and PTS period determining means for determining whether the PTS period is shorter than a predetermined period. When the PTS period is shorter than the predetermined period, recording is performed. The moving speed of the head in the main scanning direction is reduced.

  When the recording apparatus is configured in this way, it is possible to prevent the time during which the recording head is driven by the recording head driving signal from overlapping with the output timing of the recording head driving timing signal.

  In addition to the above-mentioned invention, another invention includes a counting means for counting the number of times that the PTS cycle is shorter than the predetermined period, and a count number judging means for judging whether or not the count number is larger than the predetermined number. The moving speed of the recording head in the main scanning direction is reduced when the count number exceeds a predetermined number.

  When the recording apparatus is configured in this way, the accuracy of the determination that the PTS is equal to or less than the predetermined period can be improved, and the operation of the recording apparatus can be stabilized.

  In another invention, in addition to the above-described invention, the predetermined number of times is the total number of times when recording is performed on one sheet of the recording medium.

  When the recording apparatus is configured as described above, the determination that the PTS is equal to or less than the predetermined period can be determined according to the size of the recording medium, and the determination according to the size of the recording medium can be performed. The operation can be stabilized.

  In another invention, in addition to the above-described invention, whether or not the period of the PTS is shorter than a predetermined period is determined while the recording head is located in the recording execution area.

  When the recording apparatus is configured as described above, it is possible to reduce the process of determining whether or not the output period of the PTS is equal to or less than a predetermined period, and to improve the efficiency of the control process of the recording apparatus.

  In another invention, in addition to the above-described invention, whether or not the period of the PTS is shorter than a predetermined period is determined for a section in which the recording head moves at a predetermined speed or more.

  When the recording apparatus is configured as described above, it is possible to reduce the process of determining whether or not the output period of the PTS is equal to or less than a predetermined period, and to improve the efficiency of the control process of the recording apparatus.

  In order to solve the above problems, the present invention drives a recording head in response to movement of the recording head in the main scanning direction in a recording method for recording on a recording medium while moving the recording head in the main scanning direction. A process of outputting a PTS for controlling the output timing of the recording head drive signal and a process of determining whether or not the output period of the PTS is shorter than a predetermined period, and when it is determined that the PTS period is shorter than the predetermined period Is to perform processing for reducing the moving speed of the recording head in the main scanning direction.

  When the recording apparatus is configured in this way, it is possible to prevent the time during which the recording head is driven by the recording head driving signal from overlapping with the output timing of the recording head driving timing signal.

  An inkjet printer 1 (hereinafter simply referred to as a printer) that is an embodiment of a recording apparatus according to the present invention will be described with reference to FIGS. The recording method will be described together with the operation of the printer 1.

  FIG. 1 is a block diagram showing a schematic configuration of the printer 1. As shown in FIG. 1, the printer 1 is a paper feed motor (hereinafter referred to as a PF motor) 2 that feeds paper and a paper feed motor driver (hereinafter referred to as a PF motor driver) that drives the PF motor 2. ) 3, a carriage 4, a carriage guide 5 for guiding the carriage 4, a carriage motor (hereinafter referred to as a CR motor) 6 for moving the carriage 4 along the carriage guide 5, and driving the CR motor 6. A carriage motor driver (hereinafter referred to as a CR motor driver) 7, a recording head 8 that is fixed to the carriage 4 and discharges ink droplets onto the recording paper RP, and a head driver 9 that drives and controls the recording head 8. For linear encoder 10 fixed to carriage 4, code plate 11 having slits formed at predetermined intervals, and for PF motor 2 Comprising an encoder 12 and the like of the rotary.

  The printer 1 also includes a control unit 13 that controls the entire printer 1 including the PF motor 2 and the CR motor 6 described above. The control unit 13 is a driver that controls driving of the drivers 3, 7, and 9. A control unit 14 (hereinafter referred to as a DC unit), a CPU 15, a timer IC 16 that periodically generates an interrupt signal for the CPU 15, and an interface (I / O) that transmits and receives data to and from the host computer 17. F) 18 and the ASIC 19 for controlling the resolution of printing (printing) and the drive waveform of the recording head 8 based on the recording information sent from the host computer 17 via the interface 18, the work area of the ASIC 19 and the CPU 15, PROM 20, RAM 21 and EEPROM 22 used as program storage areas, etc. Provided.

  Further, the printer 1 detects the presence or absence of the recording paper RP on the platen 23 that supports the recording paper RP being recorded, the transport roller 24 that is driven by the PF motor 2 to transport the recording paper RP, and the platen 23. And a pulley 26 attached to the rotating shaft of the CR motor 6, and a timing belt 27 that is driven by the pulley 26 and to which the carriage 4 is fixed.

  The DC unit 14 controls the PF motor driver 3, the CR motor driver 7, and the head driver 9 based on the control command sent from the CPU 15 and the outputs of the encoders 10 and 12. Note that both the PF motor 2 and the CR motor 6 are DC motors.

  Next, the configuration of a linear encoder 10 attached to the carriage 4 is shown in FIG. The encoder 10 includes a light emitting diode 28, a collimator lens 29, and a detection processing unit 30. The detection processing unit 30 includes a plurality (four) of photodiodes 31, a signal processing circuit 32, two comparators 33 and 34, a code plate 11, and the like.

  When a voltage Vcc is applied across the light emitting diode 28 via a resistor, light is emitted from the light emitting diode 28. This light is collimated by the collimator lens 29 and part of it is transmitted through the code plate 11. A large number of light blocking portions 35 and light transmitting portions 36 are alternately formed on the code plate 11 at a predetermined arrangement pitch, and the detected direction which is the arrangement direction of the light blocking portions 35 and the light transmitting portions 36 is the main scanning direction. It is arranged to become. In the present embodiment, for example, 1/360 inch-wide black rectangular light-shielding portions 35 are formed at intervals of 1/360 inch on a long transparent resin plate. That is, the light shielding portions 35 (black portions) and the light transmitting portions 36 (portions between the adjacent light shielding portions 35 and 35) having an interval of 1/360 inch are alternately arranged. . In addition, the code | symbol plate 11 may use the thing of a structure which uses a metal plate instead of a transparent resin plate, and forms a slit hole as the light transmissive part 36. FIG.

  The parallel light transmitted through the light transmitting portion 36 of the code plate 11 enters each photodiode 31 through a fixed slit (not shown) and is converted into an electric signal. The electric signals output from the four photodiodes 31 are subjected to signal processing in the signal processing circuit 32. The signals output from the signal processing circuit 32 are compared in the comparators 33 and 34, and the comparison result is output as a pulse. That is, as shown in FIG. 3A, the comparators 33 and 34 output two-phase pulse signals, pulses A and B, which are encoder signals. The high level portion of each pulse A and B corresponds to the light transmitting portion 36, and the low level portion corresponds to the light shielding portion 35.

  Pulse A and pulse B differ in phase by 90 degrees. In the printer 1, when the carriage 4 is moving from left to right (in the direction of arrow R in FIG. 1) along the main scanning direction, the pulse A is 90 degrees from the pulse B as shown in FIG. When the carriage advances from right to left (in the direction of arrow L in FIG. 1), the phase of pulse A is delayed by 90 degrees from that of pulse B as shown in FIG. In addition, the encoder 10 is configured. One period T of the pulse corresponds to one light shielding part 35 and one light transmission part 36 adjacent to each other on the code plate 11, and the period T is inversely proportional to the moving speed of the carriage 4. That is, the shorter the period T, the faster the moving speed of the carriage 4. Conversely, the longer the period T, the slower the moving speed of the carriage 4.

  On the other hand, the rotary encoder 12 for the PF motor 2 has the same configuration as the encoder 10 except that the code plate is a rotating disk (not shown) that rotates in accordance with the rotation of the PF motor 2. In the printer 1, the widths of a plurality of light shielding portions (not shown) and light transmitting portions (not shown) provided on the code plate of the encoder 12 for the PF motor 2 are each 1/360 inch. They are spaced apart by 1/360 inch. When the PF motor 2 is rotated by 1/180 inch (one cycle of the encoder 12), the paper is fed by 1/1440 inch.

  Next, the head driver 9 for ejecting ink droplets will be described with reference to FIG. The head driver 9 includes a reception buffer 37 for temporarily storing ink recording data including multi-value gradation information sent from the host computer 17 via the interface 18, a RAM 38 for storing various data, and an output. A buffer 39, a ROM 40 storing various data processing routines, a control unit 41 including a CPU, and a piezo drive signal (COM) as a print head drive signal for driving each piezo element of the print head 8 described later. ), And an interface (I / F) 44 for transmitting the print data expanded into dot pattern data to the piezo element drive circuit 43.

  In the present embodiment, recording data after binarization processing is sent from the host computer 17, so the head driver 9 stores the recording data in the reception buffer 37, and then the recording head 8. It is sufficient that the data is temporarily developed in the output buffer 39 in accordance with the arrangement of the nozzle arrays and output via the interface 43. Since the recording head 8 includes, for example, 48 nozzles for each color, after preparing dot pattern data corresponding to one scan of the recording head 8 (moving one scan in the main scanning direction) in the output buffer 39. The dot pattern data is output via the interface 44. As will be described later, the print data developed as dot pattern data is composed of, for example, 1 bit as gradation data for each nozzle. “0” indicates no dot and “1” indicates dot formation. It corresponds.

  Next, the piezo element driving circuit 43 will be described.

  FIG. 5 is a block diagram showing an internal configuration of the piezo element driving circuit 43. As shown in FIG. 5, the piezo element drive circuit 43 includes shift registers 45A to 45N, latch elements 46A to 46N, level shifters 47A to 47N, switch elements 48A to 48N, and piezo elements corresponding to the nozzles of the recording head 8. 49A to 49N and the like. The print data is composed of 1-bit data for each nozzle. Then, 1-bit data for all nozzles is input to the shift registers 45A to 45N within one recording period. That is, 1-bit data for all nozzles is serially transferred to the shift registers 45A to 45N. For example, when the bit data applied to each of the switch elements 48A to 48N configured as analog switches is “1”, piezoelectric drive vibration (COM) sent from the drive signal output circuit 42 via the interface 43 (FIG. 6 ( C)) is directly applied to the piezo elements 49A to 49N as drive signals for driving the piezo elements, and the piezo elements 49A to 49N are displaced according to the signal waveform of the piezo drive vibration (COM). Conversely, when the bit data applied to each switch element 48A to 48N is “0”, the piezo drive vibration (COM) to each piezo element 49A to 49N is cut off, and each piezo element 49A to 49N receives the previous charge. Hold.

A specific configuration for giving each 1-bit print data to the switch elements 48A to 48N will be described in detail. First, the output buffer 39 stores 1-bit print data (D) decoded by the control unit 41. Here, the print data (D) is a pulse selection signal. This 1-bit print data is given to the switch elements 48A to 48N corresponding to each nozzle of the recording head 8 within one recording cycle. Specifically, the number of nozzles of the recording head 8 is N, and the print data of the first nozzle at a position in the sub-scanning direction that is the direction orthogonal to the main scanning direction is (D1) and the printing of the second nozzle When the data is represented as (D2), the data (D1, D2, D3,..., DN) of the pulse selection signal D for all the nozzles is the recording head drive timing signal in the shift registers 45A to 45N. Serial input is performed in synchronization with a certain PTS. The PTS is sent from the DC unit 14 having PTS output means. This PTS is output based on the pulse A shown in FIG. 6A, which is an output signal of the encoder 10, and immediately before the pulse A is detected. For example, based on the following arithmetic expressions (1) and (2), the DC unit as a pulse signal shown in FIG. 14 is output.

PTS1st (m) = T (m−1) / 2 (1)
PTS2nd (m) = T (m) −T (m−1) / 2 (2)

That is, the PTS is output based on the period T (m) and the period T (m−1), which are the previous two (m-th and m−1) -th periods of the pulse A, according to the above arithmetic expression. PTS1st (m) and PTS2nd (m) are sequentially output in this order.

  Then, the drive signal output circuit 42 uses the PTS as a trigger to output to the I / F 44 a drive voltage waveform that forms an ink droplet, that is, one waveform of piezo drive vibration (COM) shown in FIG. And it collates with the bit data added to each switch element 48A-48N in the piezo element drive circuit 43, a piezo drive vibration (COM) is transferred to each piezo element 49A-49N in time with PTS from the DC unit 14. Thus, ink droplets are ejected from the nozzles. The piezo drive vibration (COM) is applied to each of the piezo elements 49A to 49N while the carriage 4 is moving in the main scanning direction, and the position of the carriage 4 and the application timing of the piezo drive vibration (COM) are controlled. Thus, ink droplets are ejected to a desired position on the surface of the recording paper RP.

  The CPU 15 detects the moving speed of the carriage 4 based on the output signal (for example, pulse A) of the encoder 10, and the PID is executed by the CPU 15 so that the carriage moving speed becomes a predetermined speed specified by the speed table held in the PROM 20. And the like, and the CR motor driver 7 is driven and controlled. The movement of the carriage 4 by the CR motor 6 and the movement of the recording paper RP by the PF motor 2 are alternately performed, and the carriage 4 moves in the main scanning direction while the movement of the recording paper RP is stopped. Then, PTS is output based on the pulse A output as the carriage 4 moves in the main scanning direction, and recording is performed on the recording paper RP by ejecting ink droplets using this PTS as a trigger. Subsequently, the recording paper RP is moved by a predetermined amount in the sub-scanning direction (a direction orthogonal to the main scanning direction), and ink droplets are ejected while moving the carriage 4 in the main scanning direction again to perform recording on the recording paper RP. By repeating this operation, a predetermined image, character, or the like is recorded on the recording paper RP.

  The CPU 15 functionally constitutes a PTS cycle determination means by reading predetermined program data from the PROM 20 or the like, and the above cycle PTS1st or PTS2nd is set while the carriage 4 moves in a recording execution area Ar described later. It is determined whether or not the short cycle PTS is shorter than a predetermined cycle (threshold cycle). The CPU 15 is also configured with a short cycle PTS counter that counts when the cycle PTS1st or PTS2nd according to the above determination is a short cycle PTS. The short cycle PTS counter is incremented whenever the cycle PTS1st or PTS2nd is determined to be the short cycle PTS, and counts the number of short cycle PTSs while the carriage 4 moves in the recording execution area Ar. . The number of short cycle PTSs is counted for each recording paper RP, and is cleared to zero when shifting to printing on a new recording paper RP. The CPU 15 constitutes a count number judging means, and judges whether or not the number of short cycle PTSs exceeds a predetermined value when recording on one recording paper RP is finished. Information is recorded in the EEPROM 22. If not, the short cycle PTS counter is cleared. When the next time, that is, when the printer 1 performs the recording operation on the next recording paper RP, the information indicating that the number of short cycle PTSs exceeds the predetermined value is stored in the EEPROM 22. In this case, the CR motor 6 is controlled so that the carriage 4 moves in the recording execution area Ar at a lower moving speed than the standard moving speed.

  Here, when the printer 1 performs the recording operation, the speed of the movement of the carriage 4 that moves in the main scanning direction in order to perform recording on the recording paper RP (hereinafter referred to as movement during the recording operation) is described with reference to FIG. While explaining. The normal speed of movement of the carriage 4 during the recording operation, that is, the speed of movement of the carriage 4 during the recording operation when the EEPROM 22 does not store information indicating that the number of short cycle PTSs exceeds the predetermined value is shown in FIG. It is controlled to move at a speed represented by the solid line portion L1. That is, the carriage 4 is accelerated at a predetermined acceleration until reaching the recording start position PS (see FIG. 1) from the movement start position MS (see FIG. 1), and from the recording start position PS to the recording end position PE. During the recording execution area Ar, it moves at a predetermined constant speed V1, which is the standard moving speed, decelerates from the recording end position PE with a predetermined negative acceleration, and stops at the movement end position ME. For each recording operation, the movement of the carriage 4 is controlled by this speed change. The ejection of ink droplets from the recording head 8 to the recording paper RP is performed in the recording execution area Ar where the moving speed of the carriage 4 is constant. In the following description, the moving speed of the carriage 4 in the recording execution area Ar is referred to as a recording execution area speed. Note that the movement start position MS, the recording start position PS, the recording end position PE, and the movement end position ME are a pulse that is an output of the encoder 10 indicating a movement amount from a reference position (not shown) set at a predetermined position of the printer 1. It is specified by calculating based on the number of A and B pulses. When the printer 1 has a configuration capable of bidirectional recording, that is, in a configuration in which recording can be performed in both the forward and backward directions of the carriage 4, the movement start position MS and the movement end position ME in FIG. In the forward path and the backward path, the position where the carriage 4 starts to move is the movement start position, and the position where the carriage 4 stops moving is the movement end position. In the recording start position PS and the recording end position PE, the recording start position is the recording start position in both the forward path and the backward path, and the recording end position is the recording end position.

  When the carriage 4 moves in the recording execution area Ar at the speed V1, since the speed V1 is a constant speed, the periods PTS1st and PTS2nd are equal and have a constant period corresponding to the speed V1. However, when dirt such as ink mist adheres to the light transmission part 36 of the code plate 11 of the encoder 10, the light projected from the light emitting diode 28 to the photodiode 31 is blocked at the dirt part. The encoder 10 will detect this dirty portion. That is, the light projected from the light emitting diode 28 to the photodiode 31 is shielded even at portions other than the original light shielding portion 35 of the code plate 11, and the width of the light transmitting portion 36 becomes narrow. As a result, for example, as shown in FIG. 8A, the pulse A1 including the portion corresponding to the dirty portion of the pulse A originally has a wavelength up to the portion including the dotted line portion A2, but corresponds to the dirty portion. The wavelength is shortened only by the dotted line portion A2. Therefore, the period T (m−1) is longer than T (m−1) in FIG. On the contrary, since the wavelength of the pulse A1 is short, the period T (m) is shorter than T (m) in FIG. As a result, as shown in FIG. 8B, as compared with the case shown in FIG. 6A, the cycle PTS1st is a longer cycle, and conversely, the cycle PTS2nd is a shorter cycle. Therefore, the output timing of the piezo drive vibration (COM) K output using the PTS (P2) output in the cycle PTS1st from the immediately preceding PTS (P1) as a trigger is delayed, and the output timing of the piezo drive vibration (COM) K is There is a possibility that the output timing of the PTS output in the cycle PTS2nd following the PTS output in the cycle PTS1st overlaps, for example, as indicated by the overlapping portion W.

  If the output timings of PTS and piezo drive vibration (COM) overlap, the drive signal output circuit 42 is connected to the PTS during application of piezo drive vibration (COM) as described above in the section of the prior art. Cannot be accepted. For this reason, the piezo drive vibration (COM) Y that should be output as indicated by the dotted line in FIG. 8C is canceled, and the ink droplets are ejected in correspondence with the piezo drive vibration (COM) Y. However, recording cannot be performed, and the recorded image is deteriorated.

  Therefore, in the printer 1, when the carriage 4 is moved at the speed V1 in the recording execution area Ar and recording is performed on one recording sheet RP, the total number of short cycle PTSs exceeds the predetermined number. In this case, it is assumed that there is a high possibility that the piezo drive vibration (COM) and the output timing of the PTS overlap, and the recording process area speed of the carriage 4 is lowered to perform the recording process. That is, the period of the pulse A can be lengthened as shown in FIG. 9A by lowering the recording execution area speed in the recording execution area Ar of the carriage 4 from the speed V1. As a result, as shown in FIG. 9B, the periods PTS1st and PTS2nd can be lengthened. In this way, in the part Z corresponding to the overlapping part W in FIG. 8C by making the periods PTS1st and PTS2nd longer, after the application of the piezo driving vibration (COM) is completed, the PTS is set to the period PTS2nd from the immediately preceding PTS. Can be avoided, and the output timing of PTS and piezo drive vibration (COM) can be avoided from overlapping, and the recorded image can be prevented from deteriorating.

  This processing operation will be described with reference to Table 1 shown in FIG. 10 and the flowchart shown in FIG.

  First, the contents of Table 1 will be described.

  Table 1 shows prescribed values when executing the processing of the flowchart shown in FIG. 11 such as a threshold period. The printer 1 has two different recording modes M1 and M2 with different resolutions. Table 1 lists various specified values when recording on the A4 size recording paper RP in each mode. In the printer 1, the recording mode M1 is a mode for recording at a recording resolution of 720 dpi, and the recording mode M2 is a mode for recording at a recording resolution of 1440 dpi. The value shown as the period in Table 1 indicates the number of counts obtained by counting one period at 6 MHz as the period, and the standard moving speed of the carriage 4 in the recording execution area Ar (see FIG. 7) of the printer 1. The speed V1 is set to a speed corresponding to the period 1110 in the mode M1 and to the period 1386 in the mode M2. One period of the pulse A corresponds to a pair of the light shielding part 35 and the light transmission part 36 each having a width of 1/360 inch of the code plate 11. Therefore, for example, when the period 1110 is converted into a speed that is a moving distance per unit time, (1/360 + 1/360) ÷ 1110 / 6000000000≈30, that is, about 30 inches / second. Note that the speed (movement distance per unit time) decreases as the period value increases, and conversely, the speed increases as the period value decreases.

  The “threshold cycle” in Table 1 indicates a threshold for determining the PTS cycle as the short cycle PTS. In the present embodiment, the mode M 1 is set to the cycle 516, and the mode M is set to the cycle 645. Note that the period corresponding to the speed V1 that is the predetermined recording execution area speed of the carriage 4 is the period 1110 in the mode M1, and therefore the periods PTS1st and PTS2nd are the periods if the pulse A is output normally. It is output as 555. That is, the PTS is a pulse with a period of 555. However, the period of the high-level part of the pulse A where the light transmission part 36 of the code plate 11 is contaminated is shortened (the period of the low-level part is long), and PTS and piezo drive vibration (COM) May be duplicated. Therefore, the CPU 15 determines that there is a possibility that the PTS and the piezo drive vibration (COM) may overlap if the cycle PTS1st or PTS2nd while the carriage 4 is moving at the speed V1 is shorter than the cycle 516. It is determined to be a short cycle PTS.

  By the way, short cycle PTS may generate | occur | produce with respect to the dust adhering temporarily to the code | symbol plate 11, and even if it is a dirt part adhering to the code | cord | chord plate 11, the adhesion width | variety is reliably short-period PTS. If the width is not wide enough to generate the short period PTS, the short period PTS may or may not be generated. Therefore, it is not appropriate to decrease the recording execution area speed as soon as a short cycle PTS occurs even once. Accordingly, the printer 1 determines that the recorded image is likely to be disturbed when the total number of short-period PTSs generated during recording on one sheet of recording paper RP exceeds a predetermined number. It is the composition which lowers. The “total number of short cycle PTSs” indicates the predetermined total number of short cycle PTSs described above, and the total number of short cycle PTSs when recording on one A4 size recording paper RP exceeds this value. In this case, the recording execution area speed at the time of recording on the next recording paper RP is reduced. In the printer 1, both modes M1 and M2 are set to 10 times, for example.

  The “low speed moving cycle” is a cycle corresponding to the moving speed when the recording execution area speed of the carriage 4 is set to a low speed when the “total number of short cycle PTSs” exceeds 10. That is, when the “total number of short cycle PTSs” exceeds 10, the recording execution area speed of the carriage 4 at the time of recording on the next recording paper RP is reduced to a speed corresponding to the “low speed moving period”. I do.

  The “inspection period” indicates a period corresponding to the moving speed of the carriage 4 that determines whether the PTS is a short period PTS. That is, when the moving speed of the carriage 4 is faster than the speed V3 corresponding to the period indicated by the “inspection target period” that is slightly slower than the speed V1, it is determined whether the PTS is a short period PTS. In the present embodiment, whether or not the PTS is the short cycle PTS when the carriage 4 is moving at a speed corresponding to the cycle of 1222 or less in the mode M1 and the cycle of 1526 or less in the mode M2. Judging.

  Next, referring to Table 1 described above, the operation of the inkjet printer 1 will be described with reference to the flowchart shown in FIG.

  When the recording operation is started, the ink jet printer 1 first determines whether or not information that the total number of short cycle PTSs exceeds a predetermined value is stored in the EEPROM 22 (step S10). In this determination, if the EEPROM 22 stores information that the total number of short-period PTSs exceeds the predetermined value (Yes in step S10), the CPU 15 that also functions as a speed control unit sends a carriage to the DC unit 14. A command is issued to decrease the recording execution area speed among the moving speeds of No. 4 (step S20).

  In the present embodiment, for example, a command is issued to the DC unit 14 so that the recording execution area speed of the carriage 4 becomes the low speed moving speed shown in Table 1, that is, the speed corresponding to the period 1133.

  Specifically, as shown in FIG. 7, the carriage 4 is accelerated from the movement start position MS to a speed V2 corresponding to the period 1133 at a predetermined acceleration, and when reaching this speed V2, the speed increases beyond this speed. Control is performed so as to perform recording by ejecting ink droplets onto the recording paper RP at a speed V2. Then, after passing through the recording end position PE, the vehicle decelerates at a predetermined negative acceleration and stops at the movement end position ME. This speed change is repeatedly recorded on the recording paper RP for each recording operation.

  On the other hand, in step S10, when the information that the total number of short cycle PTS exceeds the predetermined value is not stored in the EEPROM 22 (No in step S10), the CPU 15 moves the carriage 4 during the recording operation shown in FIG. Control is performed so as to move at the normal speed (step S30). That is, acceleration from the movement start position MS (see FIG. 1) to the recording start position PS (see FIG. 1) is accelerated to a velocity V1 at a predetermined acceleration, and recording is executed from the recording start position PS to the recording end position PE. The zone Ar moves at a speed V1, decelerates from the recording end position PE at a predetermined negative acceleration, and stops at the movement end position ME. This speed change is repeatedly recorded on the recording paper RP for each recording operation.

  Further, the CPU 15 determines whether or not the recording for one sheet of the recording paper RP is completed based on the paper detection signal from the paper detection sensor 25 (step S40). The movement of the carriage 4 (step S30) is executed while executing the processing from step S50 to step S70 described below. The processing from step S50 to step S70 is performed while the CPU 15 performs the processing of step S30, that is, while the carriage 4 repeatedly moves during the recording operation shown in FIG. 7 in which the carriage 4 moves in the recording execution area Ar at the speed V1. In addition, it is executed in the timer interrupt process by the interrupt signal periodically generated by the timer IC 16 for the CPU 15.

  If the recording for one sheet of recording paper RP has not been completed (No in step S40), whether the moving speed of the carriage 4 has reached the speed V3 corresponding to the inspection target period (whether the period is 1222 or less). Is determined (step S50). The carriage 4 starts moving from the movement start position MS until the moving speed reaches the speed V3, and after the carriage 4 passes through the recording execution area Ar and decelerates and the moving speed falls below the speed V3. Until the stop at the end position ME, the moving speed of the carriage 4 does not reach the speed V3. Therefore, No is determined in step S50, and the process proceeds to step S30. In step S30, when the carriage 4 is moving from the movement start position MS toward the recording start position PS, the movement speed of the carriage 4 becomes the speed V1 before the carriage 4 reaches the recording start position PS. To accelerate. On the other hand, when the carriage 4 moves from the recording end position PE toward the movement end position ME beyond the recording execution area Ar, the moving speed of the carriage 4 is set so that the carriage 4 stops at the movement end position ME. Slow down.

  The carriage 4 starts moving from the movement start position MS, moves at the speed V1 after the moving speed reaches the speed V3, and then decelerates through the recording execution area Ar until the moving speed falls below the speed V3. During this period, the moving speed of the carriage 4 exceeds the speed V3. Therefore, a Yes determination is made in step S50.

  When the carriage 4 accelerates from the movement start position MS and reaches the speed V3 or higher (that is, the period is 1222 or less) (Yes in step S50), the PTS output by the movement of the carriage 4 is the threshold period or less, that is, the short period PTS. Is determined (step S60). This determination (step S60) is continuously executed while the carriage 4 is moved at the speed V3 or higher. That is, when the PTS is the short cycle PTS (Yes in step S60), the short cycle PTS counter (CPU 15) is increased (step S70), the process returns to step S30 and the carriage 4 continues to move. If the PTS is not the short cycle PTS (No in step S60), the short cycle PTS counter (CPU 15) is not increased and the process returns to step S30 to continue the movement of the carriage 4.

  The carriage 4 starts moving from the movement start position MS and accelerates toward the recording start position PS until the movement speed reaches a speed V3 corresponding to the inspection target speed (cycle 1222) (No in step S50), and When the carriage 4 starts to decelerate from the recording end position PE to the movement end position ME beyond the recording execution area Ar and the moving speed becomes lower than the speed V3 (No in step S50), the PTS is short. Since it is not determined whether or not the cycle is PTS (step S60), UP of the short cycle PTS counter (CPU 15) (step S70) is not performed.

  The processing from step S30 to step S70 described above is executed until the recording of one sheet of recording paper RP is completed. When the recording of one sheet of recording paper RP is completed (Yes in step S40), it is determined whether or not the number of short cycle PTS counters (CPU 15) exceeds the total number of short cycle PTS (step S80). When the number of short cycle PTS counters (CPU 15) exceeds 10 (Yes in step S80), information on the total number of short cycle PTSs exceeding 10 is stored in the EEPROM 22 (step S90). This information is retained even after the power of the inkjet printer 1 is turned off.

  On the other hand, when the number of short cycle PTS counters (CPU 15) does not exceed 10 (No in step S80), the short cycle PTS counter (CPU 15) is reset (step S100). As described above, the information stored in the EEPROM 22 is recorded at the speed V1 which is the standard moving speed or the low speed at the next recording operation, that is, when recording on the next recording paper RP. This is used to determine whether the speed V2 is the moving speed (step S10). That is, when the EEPROM 22 stores information in which the number of short cycle PTS counters (CPU 15) exceeds the total number of short cycle PTSs (Yes in step S10), the process proceeds to step S20, and the carriage 4 as described above. Are moved at a speed V2 which is a low speed in the moving range where the recording operation is performed. On the other hand, when recording on the next recording paper RP, if information that the total number of short-period PTS exceeds the predetermined value is not stored in the EEPROM 22 in step S10 (No in step S10), The processes in steps S30 to S50, steps S30 to S60, or steps S30 to S70 described above are repeated until recording on the recording paper RP is completed.

  As described above, when the total number of short-period PTSs when recording is performed on one sheet of recording paper RP exceeds a predetermined value, the recording execution area speed is used when performing recording on the subsequent recording sheet RP. The recording is performed at a low moving speed. By reducing the recording execution area speed in this way, the period of the pulse A while the carriage 4 is moving in the recording area can be extended as a whole, and the period of the periods PTS1st and PTS2nd is also increased as a whole. . That is, the period of PTS is increased. For this reason, it is possible to prevent the piezo drive vibration (COM) and the PTS from being output redundantly.

  In the printer 1 according to the above-described embodiment, it is determined whether the PTS is the short cycle PTS (step S60) while the carriage 4 is moving at a speed equal to or higher than the speed V3 corresponding to the inspection target period. The position of the carriage 4 is detected by the encoder 10, and the determination in step S60 is executed while the carriage 4 is positioned between the recording start position PS and the recording end position PE, that is, in the recording execution area Ar. It may be.

  Since the ink droplets are not ejected while the carriage 4 is moving at a speed slower than the speed V3 or while the carriage 4 is moving outside the recording execution area Ar, the pulse is not discharged. Even if the period A is modulated and the PTS becomes a short period PTS, the quality of the image is not affected. Therefore, it is determined whether the PTS is the short cycle PTS (step S60) while the carriage 4 is moving at a speed equal to or higher than the speed V3 or while the carriage 4 is moving in the recording execution area Ar. When the carriage 4 is moving at a speed slower than the speed V3, or while the carriage 4 is moving outside the recording execution area Ar, the process of step S60 is not performed. The processing load on the CPU 15 can be reduced.

  Further, in the printer 1 according to the above-described embodiment, the total number of short cycle PTSs is 10, but is not limited to this number. When the accuracy of the linear encoder 10 is high, even when the number of occurrences of the short cycle PTS is small, there is a high possibility that a dirty portion or the like causing the short cycle PTS will cause a disturbance of the recorded image. It is preferable to set the total number of short cycle PTSs to be small. On the contrary, when the accuracy of the encoder 10 is low, there is a high possibility that the recorded image will not be disturbed even if the number of occurrences of the short period PTS is large. Is preferred.

  Further, in the printer 1 according to the above-described embodiment, when the number of short cycle PTSs generated when recording is performed on one sheet of the recording paper RP exceeds the total number of short cycle PTSs, In the next recording operation on the paper RP, the process of reducing the recording execution area speed to the speed V2 is performed. However, the number of short-period PTS generated when recording on the recording paper RP is a predetermined value. When the above is reached, a process of reducing the recording execution area speed from the speed V1 to the speed V2 may be performed immediately. The predetermined value in this case is also set appropriately according to the accuracy of the encoder 10 and the like. For example, if the accuracy of the encoder 10 is high and a short period PTS is detected even once, if the image always deteriorates, the predetermined number is set to one. If the accuracy of the encoder 10 is low, for example, if the image does not deteriorate unless a short cycle PTS is detected 10 times or more, the predetermined number is set to 10.

  Note that the printer 1 is in a state where the control of the recording execution area speed of the carriage 4 becomes unstable due to torque fluctuations of the CR motor 6 and the carriage 4 moves at a speed higher than the standard speed. Also in this case, by performing the above-described processing, it is possible to prevent the PTS cycle from increasing and the piezo drive vibration (COM) and PTS from overlapping.

  The operation of the printer 1 in the case of recording in the mode M2 is the same as the operation of the mode M1 described above, except that each specified value corresponds to the mode M2 described in Table 1. Therefore, the description is omitted.

  The encoder 10 used in the above-described printer 1 is an optical encoder. However, when another type of encoder, for example, a capacitive encoder, is used, a short cycle occurs due to a decrease in the detection accuracy of the encoder. When the PTS is output, by using the present invention, it is possible to prevent the piezo drive vibration (COM) and PTS from overlapping, and to prevent the recorded image from deteriorating. be able to.

  In the printer 1 described above, the recording head 8 is an ink head including a piezo element. However, the recording head 8 is not limited thereto, and includes a printer using a so-called bubble jet (registered trademark) ink head or a so-called dot matrix impact head. The present invention can be widely implemented in so-called serial type printers that perform recording while the recording head moves in the main scanning direction, such as a printer.

1 is a block diagram showing a schematic configuration of a printer according to a first embodiment of the present invention. FIG. 2 is a block diagram showing an electrical configuration of the linear encoder shown in FIG. 1. FIG. 3 is a waveform diagram showing pulses output from the encoder shown in FIG. 2. FIG. 2 is a block diagram showing an electrical configuration of the head driver shown in FIG. 1. FIG. 5 is a block diagram showing an electrical configuration of the piezo element driving circuit shown in FIG. 4. It is a wave form diagram which shows the output timing of a pulse A, PTS, and a piezo drive vibration (COM). It is a graph which shows the speed change of the movement at the time of the recording operation of a carriage. It is a wave form diagram which shows the output timing of a pulse A, PTS, and a piezo drive vibration (COM). It is a wave form diagram which shows the output timing of a pulse A, PTS, and a piezo drive vibration (COM). It is a figure which shows the regulation value at the time of performing the process of the flowchart shown in FIG. 3 is a flowchart illustrating an operation of a printer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer (recording apparatus) 8 ... Recording head 14 ... DC unit (PTS output means) 15 ... CPU (PTS period judgment means, count means, count number judgment means) P ... Recording Medium COM ... Printhead drive signal PTS ... Printhead drive timing signal

Claims (6)

In a recording apparatus for recording on a recording medium while moving the recording head in the main scanning direction,
A recording head driving timing signal (hereinafter referred to as PTS) output means for controlling the output timing of a recording head driving signal for driving the recording head in response to the movement of the recording head in the main scanning direction;
PTS cycle determination means for determining whether the cycle of the PTS is shorter than a predetermined cycle;
With
A recording apparatus, wherein when the period of the PTS is shorter than the predetermined period, the moving speed of the recording head in the main scanning direction is reduced. Counting means for counting the number of times the period of the PTS is shorter than the predetermined period;
Count number judging means for judging whether or not the count number is greater than a predetermined number;
With
The recording apparatus according to claim 1, wherein when the count number exceeds the predetermined number, the moving speed of the recording head in the main scanning direction is reduced.   The recording apparatus according to claim 2, wherein the predetermined number of times is a total number of times when recording is performed on one recording medium.   4. The recording according to claim 1, wherein the determination whether the period of the PTS is shorter than the predetermined period is performed while the recording head is positioned in a recording execution area. apparatus.   The determination as to whether or not the period of the PTS is shorter than the predetermined period is performed for a section in which the recording head moves at a predetermined speed or more. Recording device. In a recording method for recording on a recording medium while moving the recording head in the main scanning direction,
A process of outputting a PTS for controlling the output timing of a recording head drive signal for driving the recording head in response to the movement of the recording head in the main scanning direction;
A process for determining whether the output period of the PTS is shorter than a predetermined period;
And
When it is determined that the period of the PTS is shorter than the predetermined period, a process of reducing the moving speed of the recording head in the main scanning direction is performed.
And a recording method.

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