JP2000203091A - Printing apparatus executing two-way printing and method for adjusting recording position and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new technique for reducing a shift in recording position in a main scanning direction at a first half and a second half of a passage. SOLUTION: To make a recording position in a main scanning direction at a first half of a passage almost agree with a recording position in a main scanning direction at a second half of the passage, a frequency of driving clock signals applied to a printing head is changed along the main scanning direction at least at one of the first half and the second half. The frequency of the driving clock signals sets a value corresponding to a distance between the printing head and a printing paper measured by an optical detector at a plurality of regions sectioned from a main scanning range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording apparatus, and more particularly, to adjustment of print misalignment in bidirectional printing.

[0002]

2. Description of the Related Art In bidirectional printing, a backlash of a driving mechanism in a main scanning direction and a belt 36 pulling a carriage 31 are used.
The printing position in the main scanning direction is likely to be shifted between the forward path and the backward path due to the expansion of the print medium and the warpage of the platen supporting the print medium below. As a technique for solving such a positional deviation, for example, a technique described in Japanese Patent Application Laid-Open No. 5-69625 disclosed by the present applicant is known. In this conventional technique, a positional deviation amount (print deviation) in the main scanning direction is registered in advance, and the recording positions in the forward path and the return path are corrected based on the positional deviation amount.

[0003]

In the above-mentioned prior art, since the adjustment amount of the positional deviation is set to a constant value over the entire main scanning range, the positional deviation is not constant but along the main scanning direction. In the case where it is gradually changing, there is a problem that the positional deviation cannot be corrected well over the entire main scanning range.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art. In a printing apparatus for performing bidirectional printing, a new printing apparatus for reducing a printing position shift in the main scanning direction between the forward path and the backward path. The purpose is to provide simple technology.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a main scanning drive unit for performing bidirectional main scanning by moving at least one of the printing medium and a printing head, and the printing head. And a head drive unit for driving the print head to perform printing on the print medium.The head drive unit generates a drive clock signal to be applied to the print head, and records the print position in the main scanning direction in the forward path and the return position in the return path. A drive clock generation unit that changes the frequency of the drive clock signal along at least one of the forward path and the return path along the main scan direction so that the recording position in the main scan direction substantially coincides with the drive clock generation unit.
A memory configured to individually set the frequency of the drive clock signal in a plurality of areas obtained by dividing the main scanning range, and to store a parameter for setting the frequency of the drive clock signal for each of the plurality of areas; A reference clock generation unit that generates a reference clock signal having a frequency, and a frequency conversion unit that generates the drive clock signal by converting the frequency of the reference clock signal using a parameter read from the memory. A parameter setting unit that determines which of the plurality of areas the main scanning position of the print head is included in, and reads a parameter corresponding to an area including the main scanning position from the memory and sets the parameter in the frequency conversion unit And an optical detector fixed to the print head, and the output of the optical detector, A calculating unit that calculates a distance between the printing head and the print medium, wherein the parameter is a parameter based on an output of the calculating unit, and is a printing position in the main scanning direction in the forward path and a printing in the main scanning direction in the backward path. The frequency of the drive clock signal applied to the print head in at least one of the forward path and the return path is changed along the main scanning direction so that the positions substantially coincide with each other.

[0006]

DETAILED DESCRIPTION OF THE INVENTION Configuration of Apparatus Hereinafter, embodiments of the present invention will be described based on examples. FIG. 1 is an explanatory diagram showing a schematic configuration of a computer system having a printer as one embodiment of the present invention. This computer system includes a computer 20 and a printer 22. The printer 22 records an image on the printing paper P according to an image signal sent from the computer 20.

The printer 22 includes a sub-scanning drive mechanism for transporting the printing paper P by the paper feed motor 23, a main scanning drive mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 by the carriage motor 24, and a carriage 3.
1, a print mechanism for controlling the ejection of ink and the formation of dots by driving the print head 28 mounted on the print head 28, the paper feed motor 23, the carriage motor 24, and the print head 28.
And a control circuit 40 for exchanging signals with the operation panel 32.

On the carriage 31, a cartridge 71 for black ink and a cartridge 72 for color ink containing inks of five colors of cyan, light cyan, magenta, light magenta and yellow can be mounted. A total of six ink ejection heads 61 to 66 are formed on the print head 28 below the carriage 31.

The paper feed motor 23 performs sub-scanning by rotating the platen 26 and other rollers to convey the printing paper P. On the other hand, the carriage motor 24
By reciprocating the carriage 31, bidirectional main scanning is performed. At the time of the main scanning, the control circuit 40 drives the piezo elements (described later) of the respective color heads 61 to 66 of the print head 28 to discharge the respective color inks, and forms a multicolor image on the printing paper P.

The mechanism for transporting the printing paper P includes a gear train (not shown) for transmitting the rotation of the paper feed motor 23 to not only the platen 26 but also the paper transport rollers. The mechanism for reciprocating the carriage 31 includes a platen 2
A pulley 38 for extending an endless drive belt 36 between the carriage motor 24 and a sliding shaft 34 erected in parallel with the shaft 6 and slidably holding the carriage 31, and an origin position of the carriage 31 are detected. And a position detection sensor 39 that performs the operation.

The control circuit 40 has a drive clock generation circuit 44 for generating a drive clock signal CLK for defining the ink ejection timing of the ink ejection head 28. The drive clock generation circuit 44 has a function of changing the ink ejection position (that is, the dot recording position) in the main scanning direction by adjusting the frequency of the drive clock signal CLK. The internal configuration of the drive clock generation circuit 44 will be described later.

FIG. 2 is an explanatory diagram showing a schematic configuration inside the ink discharge head 28. As shown in FIG. Ink cartridge 71
When the (FIG. 1) and 72 (FIG. 1) are mounted on the carriage 31, the ink in the ink cartridge is sucked out through the introduction pipe 67 as shown in FIG. The heads 61 to 6 of each color of the head 28
It is led to 6. When the ink cartridge is first mounted, the operation of sucking ink into the heads 61 to 66 of the respective colors is performed by a dedicated pump. In this embodiment, a pump for suction and the print head 28 during suction are used.
The illustration and description of the configuration of the cap and the like that cover the cover are omitted.

The heads 61 to 66 for each color are provided with a plurality of nozzles Nz for each color, and a piezo element PE, which is one of the electrostrictive elements and has excellent responsiveness, is arranged for each nozzle. I have. FIG. 3 shows the structure of the piezo element PE and the nozzle Nz in detail. As shown in the drawing, the piezo element PE is provided at a position in contact with an ink passage 68 that guides ink to the nozzle Nz. As is well known, the piezo element PE is an element that distorts the crystal structure due to the application of a voltage and converts electro-mechanical energy very quickly.

In this embodiment, by applying a voltage having a predetermined time width between the electrodes provided at both ends of the piezo element PE, the piezo element PE expands by the voltage application time as shown in the lower part of FIG. , Deform one side wall of the ink passage 68. As a result, the volume of the ink passage 68 is reduced by the piezo element PE.
Is contracted in accordance with the expansion of the ink, and the ink corresponding to the contraction becomes particles lp and is ejected at a high speed from the tip of the nozzle Nz. Printing is performed by the permeation of the ink particles lp into the sheet P mounted on the platen 26.

B. FIG. 4 is an explanatory diagram illustrating a method of correcting a shift in a recording position during bidirectional printing in the present embodiment. FIG. 4 (a)
4 shows a distribution in the main scanning direction of the deviation amount Δx of the recording position when no correction is performed. FIG. 4B shows a corresponding shift in the recording position (pixel position) of the forward path and the return path. The direction of the horizontal axis x in FIG. 4A is the main scanning direction, which also corresponds to the digit direction of the printing paper. Hereinafter, the width Lmax of the printing paper along the main scanning direction is referred to as “main scanning width” or “main scanning range”.

As shown by the solid line in FIG. 4B, the deviation amount Δx between the forward print position and the return print position changes along the main scanning direction due to factors such as warpage of the platen. The horizontal axis x in FIG. 4B is defined as a coordinate axis in the main scanning direction of the forward pass, and the deviation amount Δx is defined as a value obtained by subtracting the print position of the return pass from the print position of the forward pass. In the example of FIG. 4A, the distribution of the shift amount Δx along the main scanning direction is upwardly convex, and takes a positive value substantially at the center of the main scanning Lmax and a negative value at both ends. However, the deviation amount Δ
The zero level of x is arbitrary, and in FIG. 4A, the average value of the shift amount Δx over the main scanning width Lmax is used as the zero level. Note that, depending on the type of the printing apparatus, the deviation amount Δx may have a downwardly convex distribution, contrary to FIG. 4A. Since the distribution of the deviation amount Δx differs for each model of the printing apparatus, the actual deviation amount Δx in printing is measured for each model.

FIG. 4C shows an ideal distribution of the correction amount σ for correcting the deviation amount shown in FIG. 4A. Also,
FIG. 4D shows the recording positions of the forward path and the backward path when the deviation amount Δx becomes substantially zero after the correction. The ideal correction amount σ is obtained by inverting the sign of the distribution of the deviation amount Δx shown in FIG.

FIG. 4E shows a driving clock signal C used for correcting a deviation of a recording position in the present embodiment.
The change of the frequency fCLK of LK (FIG. 1) is shown. The main scanning width Lmax is substantially equal to five regions R1 to R5.
And the driving clock signal CLK for each region
Of the frequency fCLK are individually set. In addition,
L1 to L4 indicate the positions of the boundaries of the areas. FIG.
In the regions R2 and R4 in which the correction amount σ is close to zero in (c), the frequency fCLK is set to the standard value f2, and in the region R3 where the correction amount σ is negative, the frequency fCLK is set to a value f3 larger than the standard value f2. In the regions R1 and R5 where the correction amount σ is positive, the frequency fCLK is set to a value f1 smaller than the standard value f2. The ink ejection timing of the print head 28 depends on the frequency of the drive clock signal CLK.
Therefore, the higher the frequency fCLK, the shorter the period of ink ejection, and the shorter the distance between dots in the main scanning direction. The relationship between the change in the dot recording position due to the change in the frequency fCLK and the correction of the positional deviation will be described later.

As shown in FIG. 4E, the driving clock signal C
If the frequency fCLK of the LK is individually set for each of a plurality of areas dividing the main scanning range, the ideal correction amount σ
Can be approximately realized. Note that the frequency of the drive clock signal CLK may be changed almost continuously if the capability of the drive clock generation circuit 44 (FIG. 1) permits. However, as shown in FIG.
Has the advantage that the circuit configuration becomes simpler.

The change in frequency Δx shown in FIG. 4E is applied to the return path, and the frequency fCLK is maintained at a constant value (for example, the standard value f2) on the outward path, so that the deviation amount Δx
Can be corrected so that is substantially zero. Alternatively, adjust the frequency fCLK in the forward path,
On the return path, the frequency fCLK may be kept at a constant value. Further, the frequency may be adjusted in both the forward path and the return path. That is, generally, at least one of the forward path and the return path, the frequency f of the drive clock signal CLK is
CLK may be adjusted.

It should be noted that the frequency of the main scanning drive signal for driving the carriage motor 24 is maintained at the same constant value in the forward path and the return path. Therefore, if the frequency fCLK of the drive clock signal CLK of the print head 28 is changed as shown in FIG. 4E, the recording position (ink ejection position) in the main scanning direction changes accordingly. However, it is also possible to correct the deviation of the recording position in bidirectional printing by changing the frequency of the main scanning drive signal.

The relationship between the change in the dot recording position due to the change in the frequency fCLK and the correction of the positional deviation is as follows. As described above, the higher the frequency fCLK, the smaller the distance between dots. Since the frequency fCLK is relatively low in the first and fifth regions R1 and R5 in FIG. 4E, the distance between the dots is relatively large, and the recording position on the return path is minus x compared to FIG. 4B. Direction. On the other hand, in the third region R3, the frequency fC
Since the LK is relatively high, the distance between the dots is relatively small, and the recording position on the return path is corrected so that the recording position on the return path almost matches the recording position on the return path as shown in FIG. Is done. In the case where the frequency fCLK is adjusted on the outward path, the frequency fCLK has the same distribution as that shown in FIG.
CLK may be changed.

C. FIG. 5 is a block diagram showing the internal configuration of the drive clock generation circuit 44. The drive clock generation circuit 44 includes a reference clock generation circuit 102, a frequency divider 104, an on / off gate 106, a parameter setting circuit 108, and a programmable ROM (PROM) 110. Reference clock generation circuit 102 generates a reference clock signal RCLK having a predetermined relatively high frequency. This reference clock signal RCLK is frequency-divided by the frequency divider to 1 / n to become the drive clock signal CLK. ON / OFF gate 1
Reference numeral 06 has a function of stopping or restarting the supply of the drive clock signal CLK to the print head 28 in response to a control signal from another circuit in the control circuit 40.

The PROM 110 stores the value of the frequency division ratio n in each of the regions R1 to R5 and the positions L1 to Lma of the boundaries between the regions.
x (or the width of each area). The parameter setting circuit 108 implements the frequency change shown in FIG. 4E by changing the setting of the frequency division ratio n in the frequency divider 104. The parameter setting circuit 108 has a counter (not shown) that counts the number of pulses of the drive clock signal CLK output from the on / off gate 106, and the count value of this counter and the position L of the boundary between the regions
By comparing with 1 to Lmax (or comparing the count value with the width of each area), it is determined whether the current main scanning position of the carriage 31 is any of the five areas R1 to R5. . Note that the origin position of the carriage 31 is determined in advance by a signal supplied from the position detection sensor 39 (FIG. 1) to the control circuit 40. The parameter setting circuit 108 reads the frequency division ratio n corresponding to the area including the main scanning position of the carriage 31 from the PROM 110 and sets the frequency division ratio 104 in the frequency divider 104.

As described above, the driving clock generation circuit 4
4 has an advantage that the drive clock signal CLK having a frequency suitable for each region can be easily obtained only by changing the frequency division ratio n for dividing the reference clock signal RCLK for each region. . Further, the driving clock signal C
The method of this embodiment in which the recording position is corrected by adjusting the frequency of the LK has the advantages that the circuit configuration is simpler and easier to implement than the conventional method of correcting the recording position itself.

Some printers are provided with a linear encoder for the purpose of correcting a printing shift caused by the vibration of the carriage. But,
With a linear encoder, it is difficult to correct a printing displacement caused by a warpage of the platen. However, if the frequency of the drive clock signal CLK of the print head 28 is changed along the main scanning direction as in the above embodiment,
It is also possible to correct a printing shift caused by the warpage of the platen. That is, the present invention is effective even when applied to a model provided with a linear encoder for correcting a printing shift. In addition, by applying the present invention to a model that is not provided with a linear encoder for correcting a print shift, both the print shift caused by the vibration of the carriage and the print shift caused by the warpage of the platen can be simultaneously performed. There is an effect that correction can be made.

FIG. 6 is a block diagram showing another configuration of the drive clock generation circuit 44. This drive clock generation circuit 44a is obtained by adding a PLL circuit 120 between the frequency divider 104 and the on / off gate 106 of the circuit 44 of FIG. The function of the parameter setting circuit 108a and the contents stored in the PROM 110
Some changes have been made with the addition of.

The PLL circuit 120 has a phase comparator (PD) 1
22, a low-pass filter (LPF) 124, a voltage-controlled oscillator (VCO) 126, and a frequency divider 128. The PLL circuit 120 multiplies the frequency of the clock signal CLK divided by the first frequency divider 104 by a multiplication factor m (which is equal to the frequency division ratio of the frequency divider 128) to thereby generate the drive clock signal CLK. 'Is generated and supplied to the print head 28. The frequency fCLK ′ of the drive clock signal CLK ′ has a value that is m / n times the frequency fRCLK of the reference clock signal RCLK.

The parameter setting circuit 108a sets the frequency division ratios n and m of the two frequency dividers 104 and 128 to the respective regions R1 to R5.
Respectively, so that the frequency fCLK ′ of the drive clock signal CLK ′ can be set in each of the regions R1 to R
5 can be set to a suitable value. The circuit shown in FIG. 6 has two parameters (n and m) for adjusting the frequency, so that it is possible to set the frequency in smaller units than the circuit shown in FIG. The frequency divider 104 in FIG. 5 and the frequency divider 104 in FIG.
The circuit 120 implements a frequency conversion unit (also referred to as a “frequency setting unit”) that generates a drive clock signal by converting the frequency of the reference clock signal RCLK.
However, these configurations are merely examples, and other configurations can be adopted as the frequency conversion unit (frequency setting unit).

As described above, in the above embodiment, the recording position is corrected by changing the frequency of the drive clock signal applied to the print head so that the recording position on the forward path and the recording path on the return path substantially match. There is an advantage that positional deviation can be easily corrected with a simple configuration as compared with the case where the recording position itself is corrected. In particular, since the drive clock frequency is individually set in a plurality of regions that divide the main scanning range, it is possible to realize a correction close to ideal with a simple configuration.

It should be noted that the present invention is not limited to the above examples and embodiments, but can be implemented in various modes without departing from the gist of the invention.
For example, the following modifications are possible.

(1) In the above embodiment, the main scanning Lmax is equally divided into the five regions R1 to R5. However, it is not always necessary to divide the main scanning Lmax into equal widths. It is possible. In addition, the number of area divisions is not limited to five, and may be generally divided into two or more areas. However, the larger the number of area divisions, the more ideal the correction amount σ
Therefore, it is preferable to divide the scanning width Lmax into at least five regions.

(2) The main scanning width Lmax (main scanning range) in which the frequency fCLK is adjusted may be changed according to the width and thickness of the printing paper actually used. For example, the width and thickness in the main scanning direction are different between a postcard and A4 paper, and the width in the main scanning direction is different depending on the printing orientation (vertical or horizontal) even on the same printing paper. Therefore, parameters (n, m, L1 to Lmax) corresponding to a plurality of combinations of the thickness, size, and orientation of the printing paper are registered in the PROM 110, respectively.
It is also possible that the parameter setting circuit 108 uses appropriate parameters according to the thickness and size of the printing paper designated by the computer 20.

(3) In the above embodiment, the main scanning is performed by moving the print head. Instead, the printing paper may be moved. That is, the present invention is generally applicable to a printing apparatus having a bidirectional printing function of performing bidirectional main scanning by moving at least one of a print medium and a print head.

(4) In the above embodiment, a part of the configuration realized by hardware may be replaced by software, and a part of the configuration realized by software may be replaced by hardware. It may be. For example, part of the circuits shown in FIGS. 5 and 6 (for example, the parameter setting circuits 108 and 108).
The function a) may be realized by a microprocessor executing a computer program stored in a recording medium. A part or all of the functions of the control circuit 40 may be executed by a microprocessor (CPU or the like) of the computer 20.

As a recording medium, a flexible disk, a CD-ROM, a magneto-optical disk, an IC card,
Various computer-readable media such as a ROM cartridge, a punched card, a printed matter on which a code such as a barcode is printed, an internal storage device (memory such as RAM and ROM) and an external storage device of the computer can be used.

D. Method for Obtaining Distribution Information of Shift Ax FIG. 7 to FIG. 12 show an embodiment showing a method for obtaining distribution information of the shift amount. FIG. 7 is a cross-sectional view of the recording apparatus of FIG. 1 as viewed from the left side of the drawing. 80 is a photo reflector fixed to the carriage, 81 is a light emitting portion of the photo reflector, 82 is a light receiving portion of the photo reflector, and a light beam 83 emitted from the light emitting portion 81 is reflected on the printing paper P and reaches the light receiving element 82 The optical axis is set to perform.

As shown in FIG. 8, when the printing paper P is fed, the carriage 31 on which the photoreflector 80 is fixed is moved to R1 in the main scanning direction. The photo reflector 80 has a circuit diagram configuration shown in FIG. 130, 13
1 is a resistor, 132 is a light emitting diode (LED), 133
Is a phototransistor. The photoreflector 80 has output characteristics as shown in FIG. 10, and the photocurrent remarkably changes depending on the distance from the printing paper P. As the photocurrent changes, the voltage of the output signal 132 changes. FIG. 11 is a block diagram for converting the output signal 132 into the above-described parameter value dividing ratio n. 200 is a calculation unit, 2
01 converts the voltage value of the output signal 132 into a digital value
An A / D converter 202 stores a table for calculating a distance from the output result of the A / D converter in accordance with the output characteristics shown in FIG. 10 and converting the distance into a frequency dividing ratio n according to the distance. R
4 shows an example of a table stored in the OM 202.

Reference numeral 203 denotes a control circuit for sampling the A / D converter 201 and writing the result of the ROM 202 into the RAM 204.

After the carriage 31 stops at R 1, the frequency division ratio n is calculated by the calculation unit 200 from the result of the photo reflector 80 and stored in the RAM 204.

Next, the carriage 31 is moved to the region R2,
Similarly to R1, the frequency division ratio n corresponding to the distance between the print head 28 and the print paper P is stored in the RAM 204. By performing the same for R3 to R5, the frequency division ratio n corresponding to the distance between the print head 28 and the printing paper P in each area is stored in the RAM2.
04. Further, as can be seen from the characteristics of FIG. 10, it is understood that the distance from the photoreflector 80 to the printing paper P needs to be set between 0.5 and 4 mm.

Although the printing speed is deteriorated, the distribution information of the shift amount Δx described in the above-described embodiment is acquired every time the main scanning is performed, and the recording position shift is corrected, so that a higher image quality bi-directional can be achieved. Printing results can also be obtained.

Further, since the acquisition of the distribution information of the deviation amount Δx for adjusting the recording position in the printing apparatus includes processing by a computer program, a recording medium on which a program for realizing such control is recorded. Can be adopted as an embodiment. Such recording media include flexible disks and CD-ROs.
M, a magneto-optical disk, an IC card, a ROM cartridge, a punched card, a printed matter on which a code such as a barcode is printed, a computer internal storage device (RAM or ROM)
Various computer-readable media, such as a memory (e.g., memory) and an external storage device, can be used. Further, an embodiment as a program supply device for supplying a computer program for realizing acquisition of distribution information of the deviation amount Δx for performing the above-described recording position adjustment to the computer via a communication path is also possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a printer 22 as one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of a dot recording head of the printer of the present invention.

FIG. 3 is an explanatory diagram showing a dot formation principle in the printer of the present invention.

FIG. 4 is an explanatory diagram showing a method for correcting a deviation of a recording position in bidirectional printing in the embodiment.

FIG. 5 is a block diagram showing an internal configuration of a drive clock generation circuit 44.

FIG. 6 is a block diagram showing another configuration of the drive clock generation circuit 44.

FIG. 7 is an explanatory view showing a carriage 31 to which a photo reflector 80 is fixed.

FIG. 8 is an explanatory diagram showing a method for measuring a distance between a print head and a print sheet.

FIG. 9 is an explanatory diagram showing a circuit configuration of the photoreflector 80.

FIG. 10 is an explanatory diagram showing characteristics of a photoreflector 80.

FIG. 11 is a block diagram showing another configuration of the drive clock generation circuit 44 using the photo reflector 80.

FIG. 12 is an explanatory diagram showing an example of a table stored in a ROM 202.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 ... Computer 22 ... Printer 23 ... Paper feed motor 24 ... Carriage motor 26 ... Platen 28 ... Print head 31 ... Carriage 32 ... Operation panel 34 ... Slide Drive shaft 36 Drive belt 38 Pulley 39 Position detection sensor 40 Control circuits 44, 44a Drive clock generation circuit 61-66 Ink ejection head 67 Introducing pipe 68 ... Ink passages 71, 72 ... Ink cartridge 80 ... Photo reflector 81 ... Photo reflector light emitting unit 82 ... Photo reflector light receiving element 83 ... Light flux 102 ... Reference clock generation Circuit 104: frequency divider 106: on / off gate 108, 108a: parameter setting circuit 110: PROM 1 0: PLL circuit 122: phase comparator 124: low-pass filter 126: voltage-controlled oscillator 128: frequency divider 200: calculating unit 201: A / D converter 202 · ROM 203 · · · control circuit 204 · · · RAM CLK, CLK '· · · driving clock signal P · · · printing paper R1 to R5 · · · divided region of main scanning width RCLK · · · reference clock signal fCLK fCLK ': drive clock frequency fRCLK: reference clock frequency

Claims (4)

[Claims] 1. A printing apparatus having a bidirectional printing function for printing an image on a print medium while performing main scanning in a reciprocating manner, wherein at least one of the print medium and a print head is moved to move the print medium. A main scanning drive unit that performs scanning, and a head drive unit that drives the print head to perform printing on the print medium, wherein the head drive unit generates a drive clock signal to be given to the print head. A drive for changing the frequency of the drive clock signal along the main scanning direction in at least one of the forward path and the backward path so that the recording position in the main scanning direction on the outward path substantially matches the recording position in the main scanning direction on the backward path. A clock generation unit; and a drive clock generation unit configured to individually set a frequency of the drive clock signal in a plurality of regions that divide a main scanning range. A memory for storing parameters for setting the frequency of the drive clock signal for each of the plurality of regions; a reference clock generation unit for generating a reference clock signal having a predetermined reference frequency; A frequency conversion unit that generates the drive clock signal by converting the frequency of the reference clock signal using the set parameters; and in which of the plurality of regions the main scanning position of the print head is included. Determining a parameter corresponding to a region including the main scanning position from the memory and setting the parameter in the frequency conversion unit; an optical detector fixed to the print head; and the optical detector A calculation unit that calculates a distance between the print head and a print medium, according to the output of the parameter. Printing apparatus which is a parameter based on the output of the calculation section. 2. The printing apparatus according to claim 1, wherein the parameter setting unit changes a division of the plurality of areas and a value of the parameter according to a width of a printing medium to be used in a main scanning direction. A printing apparatus comprising: 3. A print position adjusting method for adjusting a print position in a forward pass and a return pass during bidirectional printing, wherein main scan driving for performing bidirectional main scan by moving at least one of a print medium and a print head. Means, and a head driving means for driving the print head to perform printing on the print medium, wherein the head drive means generates a drive clock signal to be applied to the print head and a main scanning direction in an outward path. Drive clock generation means for changing the frequency of the drive clock signal along the main scanning direction on at least one of the forward path and the backward path so that the recording position of the main scanning direction substantially coincides with the recording position of the return path. The driving clock generating means individually sets the frequency of the driving clock signal in a plurality of areas divided into the main scanning range. Storage means for storing parameters for setting the frequency of the drive clock signal for each of the plurality of regions; reference clock generation means for generating a reference clock signal having a predetermined reference frequency; and Frequency conversion means for generating the drive clock signal by converting the frequency of the reference clock signal using the read parameters; and wherein the main scanning position of the print head is included in any of the plurality of regions. Parameter setting means for determining from the storage means a parameter corresponding to an area including the main scanning position and inputting the parameter to the frequency conversion means; an optical detection means mounted on the print head; Calculating means for calculating the distance between the print head and the print medium based on the output of the expression detecting means. The parameter is a parameter based on the output of the calculating means, and in at least one of the forward pass and the return pass, such that the print position in the main scan direction in the forward pass substantially coincides with the print position in the main scan direction in the return pass. A recording position adjusting method, wherein a frequency of a drive clock signal applied to the print head is changed along a main scanning direction. 4. A recording medium on which a program for adjusting a recording position is recorded in a computer-readable manner on a forward path and a return path during bidirectional printing, wherein at least one of the print medium and the print head is moved to move the both. Main scanning driving means for performing main scanning in the direction, head driving means for driving the print head to perform printing on the print medium, optical detection means mounted on the print head, and application to the print head. A drive clock signal is generated, and the frequency of the drive clock signal is adjusted in at least one of the forward path and the return path so that the print position in the main scan direction on the forward path substantially matches the print position in the main scan direction on the return path. A function of changing along the scanning direction, and a frequency of the driving clock signal in a plurality of areas divided into a main scanning range. And a function of individually storing parameters for setting the frequency of the drive clock signal for each of the plurality of regions; a function of generating a reference clock signal having a predetermined reference frequency; A function of generating a drive clock signal by converting the frequency of the reference clock signal using the parameters, and determining which of the plurality of areas the main scanning position of the print head is included in, and determining the main scanning position. A function of reading a parameter corresponding to an area including the area and converting a drive clock signal; and a function of calculating a distance between the print head and a print medium based on an output of the optical detection means. And at least one of the forward path and the backward path so that the recording position in the main scanning direction substantially coincides with the recording position in the backward path. A recording medium on which a program for realizing, by a computer, a function of changing the frequency of a drive clock signal applied to a printing head along a main scanning direction is recorded.