JP3972946B2 - Printing position suitability determination method and printing apparatus - Google Patents

Description

  The present invention relates to a method for determining suitability of a print position on a recording sheet by a print head adapted to perform printing in both reciprocating directions while reciprocating, and a printing apparatus that implements this method. The present invention relates to a method for determining suitability of a relative positional relationship between printing in a forward direction and printing in a backward direction by a print head, and a printing apparatus that implements this method.

For example, in a printing apparatus having an ink jet type or wire dot type print head, the print head normally feeds the recording paper while the recording paper is intermittently fed in a predetermined direction during the printing operation. The print head is configured to reciprocate in a direction orthogonal to the direction so that the print head can perform desired printing on the entire area to be printed on the recording paper.
In order to increase the efficiency of the printing operation, generally, the print head performs printing in both reciprocating directions. In this case, it is necessary to appropriately set the relative positional relationship between the printing in the forward direction and the printing in the backward direction on the recording paper by the print head. This is because if this relative positional relationship is not appropriate, there will be a deviation between printing in the forward direction and printing in the backward direction. For example, when a vertical ruled line extending over several lines is printed, This is because it does not become a single straight line but may appear as several line segments shifted from each other in the moving direction of the print head in an extreme case.

  However, it is relatively difficult to properly set the relative positional relationship between the printing in the forward direction and the printing in the backward direction. This difficulty is that the print head is moving during the printing operation and that there must be a gap between the print head and the recording paper. Due to the fact that there is always a time difference from the end timing of printing on the recording paper, the dimensional error of parts including the print head, the variation in the mounting position of the print head, or the thickness of the recording paper used, This is due to the fact that the size of the gap with the recording paper varies.

  For example, the ink jet print head will be described more specifically. The ink reaches the recording paper at a timing delayed from the ink ejection timing of the print head, but the print head is moving during the printing operation. Therefore, the printing position on the recording paper is shifted to the front side when viewed in the moving direction of the print head from the position where the print head actually ejects ink. This shift amount is determined by the moving speed of the print head, the size of the gap between the print head and the recording paper, and the ink ejection speed in this gap. Of these, the size of the gap between the print head and the recording paper is Because of fluctuations due to component errors, variations in the print head mounting position, or depending on the thickness of the recording paper used, this also causes the shift amount to vary.

  In addition, as described above, this shift occurs on the front side as viewed in the moving direction of the print head from the position where the print head actually ejected ink. It should also be noted that the sides shifted in are opposite to each other. As a result, if there is a specific variation in the shift amount due to a variation in the size of the gap between the print head and the recording paper, for example, this variation will occur when viewed between forward printing and backward printing. The size appears twice.

  In a printing apparatus having a print head that reciprocates under such a background, first, whether or not the relative positional relationship between forward printing and backward printing is appropriate is determined at the stage before shipment. If this is determined to be inappropriate, adjustments are made to make it appropriate. This adjustment is usually performed by changing the amount of timing delay from the start of print head movement to the start of printing.

  Further, in the pre-shipment stage described above, even if the relative positional relationship between the forward direction printing and the backward direction printing is properly adjusted, this relative positional relationship is not obtained when the printing apparatus is actually used. It may be inappropriate. For example, in the pre-shipment stage, standard thickness recording paper is used to adjust the relative positional relationship appropriately. For example, a special thickness recording paper is used on the consumer side. Or, although rare, if the mounting position of the print head fluctuates for some reason, it is necessary to adjust this relative positional relationship again.

  When adjusting the relative positional relationship at each stage, generally, printing is actually performed on recording paper, and the deviation between forward printing and backward printing is based on the printing result. A method is adopted in which an adjustment value is determined so that it disappears, and the amount of delay in timing from the start of printing head movement to the start of printing is changed in accordance with this adjustment value. As described above, when determining an adjustment value that eliminates the deviation between forward printing and backward printing based on the printing result, the relative positional relationship between forward printing and backward printing is determined. It is necessary to visually determine the suitability of this, and the following method has been conventionally employed for this determination.

  That is, as shown in FIG. 21, a ruled line pattern for, for example, three lines is formed on the recording paper by actual printing. More specifically, in the first line, a plurality of vertical ruled lines 1 are printed in the printing direction indicated by the arrow 2, and then the line is changed as indicated by the arrow 3, and then the printing direction is changed as indicated by the arrow 4, Similarly, a plurality of vertical ruled lines 5 are printed on the second line, and after a line feed as indicated by an arrow 6, a plurality of vertical ruled lines 7 are also displayed in three lines with the same printing direction as the first line as indicated by an arrow 2. Printed on the eyes.

  In such a ruled line pattern, when the vertical ruled line 1 of the first line, the vertical ruled line 5 of the second line, and the vertical ruled line 7 of the third line are aligned on a straight line, the forward printing and the backward printing are relative to each other. It is determined that the positional relationship is appropriate. In FIG. 21, since the vertical ruled lines 1, 5, and 7 are not aligned on a straight line, it is determined that the relative positional relationship between the forward printing and the backward printing is inappropriate. Therefore, an adjustment value is selected such that these vertical ruled lines 1, 5 and 7 are a single straight line, and, for example, the amount of timing delay from the start of printing head movement to the start of printing is changed according to this adjustment value. It is corrected to.

  In determining the suitability of the print position as described above, a human visually observes the determination pattern actually printed. However, it is extremely difficult to determine the suitability of the printing position using the ruled line pattern shown in FIG. In FIG. 21, the state in which the relative positional relationship between the forward direction printing and the backward direction printing is inappropriate is exaggerated for convenience of explanation. Therefore, the deviation between the vertical ruled lines 1, 5, and 7 is not illustrated. Although shown quite large, in practice, the vertical ruled lines 1, 5 and 7 are deviated only within the thickness range of the lines, for example, in order to determine the suitability of the relative positional relationship. In such a situation, it will be necessary to determine whether or not they are aligned, and it will be understood that it is extremely difficult for the viewer to judge the suitability with high accuracy and with confidence. .

  The determination using the ruled line pattern as described above also has the following problem. This will be described with reference to FIGS. 22, 23 and 24, respectively. 22, 23, and 24, elements corresponding to those shown in FIG. 21 are denoted by the same reference numerals, and redundant description is omitted. FIG. 22 shows an example of a ruled line pattern printed when the print head is tilted with respect to its moving direction. In such a situation, since the vertical ruled lines 1, 5 and 7 cannot be arranged on a straight line, it is even possible to select an adjustment value such that these vertical ruled lines 1, 5 and 7 become one straight line. Impossible.

  FIG. 23 shows a printed example of a ruled line pattern when the head surface of the print head and the recording surface are not parallel. In this case, the vertical ruled lines 1, 5 and 7 can be connected to each other by one line, and there are adjustment values for making this state. Even if connected by a single line, it is not a straight line, so it is extremely difficult to determine this state.

  FIG. 24 shows an example of printing a ruled line pattern when the moving speed of the print head varies. In such a situation, among the plurality of vertical ruled lines 1, 5 and 7, ones that are aligned on a straight line between each row and ones that are not so are mixed, so it is extremely difficult to determine the suitability of the relative positional relationship. Have difficulty. Accordingly, an object of the present invention is to provide a printing position suitability determination method and a printing apparatus that implements this method, which can solve the various problems described above.

  The present invention is a method for determining the suitability of the relative positional relationship between printing in a forward direction and printing in a backward direction on a recording sheet when a reciprocating print head performs printing in both reciprocating directions. In order to solve the technical problem described above, in the invention according to claim 1, in one of the two print areas adjacent to each other on the recording paper, one print area is provided with a piece of the print head. The reference pattern is printed according to the direction movement, and the comparison process is compared with the reference pattern in the other print area, in which a comparison pattern that should be the same pattern as the above-described reference pattern is printed according to the bidirectional movement of the print head. And determining whether or not the two are equal, and determining that the relative positional relationship is appropriate when the two are determined to be equal. When the relationship is optimal, the portion printed according to the forward movement of the print head and the portion printed according to the backward movement of the print head completely overlap each other, and the relative positional relationship is inappropriate It is characterized by being printed with a thicker or double line than the reference pattern.

  Thus, according to the first aspect of the present invention, the comparison pattern that should be the same as the reference pattern printed according to the one-way movement of the print head is printed according to the two-way movement of the print head. The information regarding the relative positional relationship between the printing and the printing in one direction appears in the comparison pattern. That is, when the relative positional relationship is optimal, the comparison pattern includes a pattern in which a portion printed in accordance with the forward movement of the print head and a portion printed in accordance with the backward movement of the print head overlap each other. When the target positional relationship is inappropriate, the comparison pattern is printed with a thicker or double line than the reference pattern. Therefore, it is possible to determine whether or not the relative positional relationship is appropriate by relatively comparing the comparison pattern and the reference pattern.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the reference pattern and the comparison pattern should give a series of vertical ruled lines.
When the shape of the reference pattern and the comparison pattern is selected in this way, when the relative positional relationship is appropriate, a vertical ruled line having a uniform thickness appears in both the reference pattern and the comparison pattern, while the relative positional relationship is When it is inappropriate, only a portion corresponding to the comparison pattern in the vertical ruled line appears thick or a double line appears.

The invention according to claim 3 is applied to the invention according to claim 1 or 2, and in the printing step, both the first and second printing areas are printed by one line by the print head. The comparison pattern is printed by moving the print head bidirectionally without line breaks.
When the printing process is performed in such a manner, both the reference pattern and the comparison pattern can be within the printing range of one line of the print head.

Invention of Claim 4 is applied to invention of Claim 3, Comprising: In a printing process, according to one direction movement of a print head, a reference pattern and a part of comparison pattern are printed, The remainder of the comparison pattern is printed as the print head moves in the other direction.
When the printing process is performed in such a manner, both the reference pattern and the comparison pattern can be printed by one reciprocation of the print head.

The invention according to claim 5 is applied to the invention according to any one of claims 1 to 4, and in the printing step, a set of a plurality of types of reference patterns and comparison patterns is printed. It is a feature.
When printing is performed in such a manner, the determination process compares each of a plurality of types of sets of reference patterns and comparison patterns.

As described above, when a set of a plurality of types of reference patterns and comparison patterns is printed, it is preferable that the sets of the plurality of types are printed so that they are aligned in the moving direction of the print head, that is, the row direction, and more preferably These plural kinds of sets are made to fall within the printing range for one line by the print head.
The invention according to claim 6 is applied to the invention according to any one of claims 1 to 5, wherein a print area where a reference pattern is printed and a print area where a comparison pattern is printed are: It is characterized by being located via a boundary extending in the moving direction of the print head.

When the two print areas are arranged in such a manner, the comparison between the reference pattern and the comparison pattern is a vertical comparison if the line direction is viewed sideways.
The invention according to claim 7 is applied to the invention according to any one of claims 1 to 6, wherein a print area where a reference pattern is printed and a print area where a comparison pattern is printed are: It is characterized by being positioned so as to be aligned in the moving direction of the print head.

  When the two print areas are arranged in this manner, the comparison between the reference pattern and the comparison pattern is a left-right comparison if the line direction is viewed sideways. Since the invention described in claim 7 is also applied to the invention described in claim 6, the technical features described in claims 7 and 6 can be combined. In this case, the print area on which the reference pattern is printed and the print area on which the reference pattern is printed are arranged so as to be aligned in the direction in which the print head moves and also in the direction orthogonal to the movement direction. become.

The present invention is also directed to a printing apparatus that performs the above-described printing position suitability determination method.
According to an eighth aspect of the present invention, there is provided a printing apparatus in which a reciprocating print head performs printing in both reciprocating directions. One of the areas is printed with a reference pattern according to the unidirectional movement of the print head, and the other print area is printed with a comparison pattern that should be the same pattern as the reference pattern according to the bidirectional movement of the print head. And a printing unit that compares the comparison pattern with a reference pattern to determine whether or not they are equal, and a determination unit that determines that the relative positional relationship is appropriate when both are equal. When the relative positional relationship is optimal, the comparison pattern has a portion printed according to the forward movement of the print head and a portion printed according to the backward movement of the print head. Include those completely overlaps the stomach, a relative positional relation when is improper is characterized to be printed thicker or than the reference pattern, or with a double line.

  According to such a configuration, the printing position suitability determination method according to claim 1 can be performed in response to an instruction to execute printing for judging the printing position suitability. The same effects as described above can be obtained.

  According to the first aspect of the present invention, the reference pattern is printed in one of the two print areas adjacent to each other on the recording paper according to the one-way movement of the print head, and the other print area is printed in the other print area. A comparison pattern that should be the same pattern as the above-described reference pattern is printed according to the bidirectional movement of the print head, the comparison pattern is compared with the reference pattern, and it is determined whether or not they are equal. Since the relative positional relationship between the forward direction printing and the backward direction printing is determined to be appropriate at this time, the relative comparison between the comparison pattern and the reference pattern is performed in this determination. Compared with the absolute determination of one pattern, the accuracy and reliability of determination by the human eye can be improved. Further, since the comparison pattern and the reference pattern can be printed at positions close to each other, the relative comparison as described above can be easily performed. Furthermore, when the relative positional relationship between the forward printing and the backward printing by the print head is optimal, the comparison pattern includes a portion printed according to the forward movement and a portion printed according to the backward movement of the print head. When the relative positional relationship is inappropriate, including those that overlap each other, the comparison pattern is printed with a thicker or double line than the reference pattern, making it easy to compare the two Can be done.

  According to the second aspect of the present invention, since the reference pattern and the comparison pattern should both give a series of vertical ruled lines, the relative positional relationship between the forward printing and the backward printing is appropriate. In some cases, vertical ruled lines having uniform thickness appear in both the reference pattern and the comparison pattern. On the other hand, when the relative positional relationship is inappropriate, only the portion corresponding to the comparison pattern in the vertical ruled lines is thicker. Appearance or a double line appears, and it is possible to determine the suitability of the relative positional relationship more easily and without error. In addition, even if the print head is tilted with respect to its moving direction or the head surface of the print head and the recording surface are not parallel, there is no problem in comparing the comparison pattern with the reference pattern. Absent.

  According to the invention described in claim 3, in the printing process, both the first and second printing areas are within the printing range for one line by the print head, and the comparison pattern is printed without line breaks. Since the printing is performed by moving the head bidirectionally, both the reference pattern and the comparison pattern can be within the printing range of one line of the printing head, and therefore the printing area or the recording paper can be saved. be able to. In addition, a large number of determination patterns can be printed on one sheet of recording paper.

  According to the fourth aspect of the present invention, in the printing process, the reference pattern and a part of the comparison pattern are printed according to the one-way movement of the print head, and the remainder of the comparison pattern is printed according to the other-direction movement of the print head. Therefore, both the reference pattern and the comparison pattern can be printed by one reciprocation of the print head. Therefore, it is possible to efficiently perform printing for determining the suitability of the printing position.

  According to the invention described in claim 5, since a set of a plurality of types of reference patterns and comparison patterns is printed in the printing step, a comparison utilizing the characteristics of each type of reference pattern and comparison pattern is performed in the determination step. This can be performed, and the accuracy of the print position suitability determination can be further increased. In addition, when a plurality of sets of reference patterns and comparison patterns are printed in this way, the plurality of sets are printed so as to be aligned in the moving direction of the print head, that is, in the row direction. Is within the printing range for one line by the print head, the efficiency of the printing operation can be increased and the printing area can be saved.

According to the sixth aspect of the present invention, the print area in which the reference pattern is printed and the print area in which the comparison pattern is printed are located via the boundary extending in the moving direction of the print head. If the image is viewed sideways, the reference pattern and the comparison pattern can be compared vertically.
According to the seventh aspect of the present invention, the print area on which the reference pattern is printed and the print area on which the comparison pattern is printed are positioned so as to be aligned in the moving direction of the print head. If it is visually observed toward the point, it becomes possible to compare the reference pattern and the comparison pattern on the left and right.

  According to the printing apparatus of the eighth aspect, the printing position suitability determination method according to the first aspect can be carried out, and the same effect as the effect described in relation to the first aspect can be obtained. Can do.

  First, as an example of a printing apparatus to which the printing position suitability determination method according to the present invention can be applied, an inkjet printing apparatus 11 whose main part is shown in FIG. 16 will be described. The ink jet printing apparatus 11 includes a main body cover 12 indicated by an imaginary line, and a main body frame 13 is disposed in the main body cover 12. In addition, the printing apparatus 11 basically has a platen 14, a carriage drive mechanism 16 for driving the carriage 15, and a recording ink contained in an ink cartridge 17 ejected toward the recording paper 18. And an ink ejection mechanism 19, and these elements are held directly or indirectly by the main body frame 13.

The platen 14 is rotatably supported by the main body frame 13 at both ends thereof. A platen gear 20 is attached to the left end portion of the platen 14 according to FIG. 16, and the platen gear 20 is rotated by a feed motor through a gear train (not shown). It is rotated to send in the direction of.
The carriage 15 is held by the guide rod 21 on the side closer to the platen 14 and is held by the guide rail 22 on the side farther from the platen 14, thereby being movable in the axial direction of the platen 14. The guide rod 21 is supported by the main body frame 13, and the guide rail 22 is formed as a part of the main body frame 13.

  A predetermined portion of the endless belt 23 is fixed to the carriage 15 on the lower surface side of the carriage 15. The endless belt 23 is stretched between pulleys 24 and 25 arranged at both end portions of the main body frame 13 so as to extend in parallel with the guide rod 21 and the guide rail 22. One pulley 25 is mounted on a drive shaft of a carriage drive motor 26 made of, for example, a stepping motor. Therefore, the carriage 15 can be reciprocated in a desired direction along the guide rod 21 and the guide rail 22 via the pulley 25 and the endless belt 23 by driving the carriage drive motor 26.

  A print head 27 is mounted on such a carriage 15. The print head 27 changes the volume of an ink chamber (not shown) that accommodates ink supplied from the ink cartridge 17 with a piezoelectric element or the like, so that the ink in the ink chamber is directed from the nozzle toward the recording paper 18. It is an ink jet head that performs printing by jetting. Such a print head 27 may be an ink jet head that handles liquid ink from the beginning, or may be a hot melt type ink jet head that heats and melts solid ink pellets to form liquid ink.

  An encoder scale 28 is disposed along the movement path of the carriage 15. Although not shown, the encoder scale 28 is provided with optically readable slits with a density of, for example, 90 per inch and distributed in the longitudinal direction. On the other hand, the carriage 15 reads a slit on the encoder scale 28, and an encoder signal corresponding to the speed of the carriage 15, that is, a pulse period corresponding to the interval between the slits, and the number of pulses corresponding to the number of slits. An encoder element 29 (see FIG. 18) for generating the encoder signal is provided. The encoder element 29 includes, for example, a photocoupler composed of two sets of light emitting elements and light receiving elements, and the phases of the light emitting elements are shifted by 3/4 period between the two light emitting elements and the two light receiving elements. The moving direction of the carriage 15 can be detected by the phase difference between the pulses output from the two light receiving elements.

  FIG. 17 is a block diagram showing the control system of the inkjet printer 11. As shown in FIG. 17, the CPU 30 includes a communication interface unit 100 for exchanging various data with an external electronic device 200 via a bus 304 such as a data bus or an address bus, an LCD display, An operation panel 101 including a display unit 102 including an LED display lamp and an input switch 103, a drive circuit 34 for driving motors for printing and image reading, a print head drive circuit 35 for driving a print head, and an encoder element 29 A timing pulse generator 310 that generates various timings based on signals from the image reader, an image reading unit 400 that reads a document such as a printed matter with a photoelectric conversion device such as a CCD, a ROM 301, a RAM 302, and a nonvolatile memory (RAM) 303 described later. It is connected to each part.

  The ROM 301 includes a reception control program for receiving image data and control data from the external electronic device 200, a paper feed drive circuit 341 of the feed motor 261, a carriage drive circuit 342 of the carriage motor 262, and a print head based on the created recording data. A head control program for driving and controlling the drive circuit 35, a program for controlling display and input to the operation panel 101, a program for controlling the image reading unit 400 to take in image data, a print control program for controlling printing of image data, A program for performing printing for correcting the printing timing peculiar to the present plan, updating the correction amount, etc., judgment pattern data peculiar to the present plan, a correction amount table 36 (FIG. 20), and the like are stored.

  The RAM 302 also stores a buffer for storing image data and control data received from the external electronic device 200, image data read by the image reading unit 400, and various memories and buffers for performing print control. In addition, a work area is set as a temporary storage for executing various processes of the present plan. Further, in the nonvolatile memory 303, various setting values to be stored even after the apparatus main body is turned off, for example, areas such as the correction amount memory 360 are set, and various values are stored.

  FIG. 18 shows a part of the control system shown in FIG. 17 in more detail. The timing pulse generator 310 shown in FIG. 17 is configured as a gate array 31. The gate array 31 detects a rising edge of the encoder signal output from the encoder element 29, generates a reference pulse at the detection timing, and the reference pulse output from the edge detection circuit 32. And a print timing generation circuit 33 for generating a print timing signal.

  The CPU 30 receives the speed data (the count value of the pulse width of the encoder signal) output from the print timing generation circuit 33 as an input, and determines the moving speed of the carriage 15 to the motor drive circuit 34 for the carriage drive motor 26. The pulse width of the drive signal to be given is calculated. The CPU 30 receives the position control pulse (reference pulse) output from the edge detection circuit 32 as an input, and calculates the current position of the carriage 15. Further, the CPU 30 writes data for performing later-described delay count values, permission of a print start signal, designation of an output pulse selection signal, and the like in a register 331 in the gate array 31.

  A print timing signal as a timing pulse output from the print timing generation circuit 33 is input to the print head drive circuit 35. The print head drive circuit 35 generates a print head drive pulse that satisfies the pulse width and voltage conditions necessary for operating the print head 27 based on the print data given by the CPU 30 in accordance with the timing given by the print timing signal. The print head 27 receives this print head drive pulse and ejects ink onto the recording paper 18 (FIG. 16) at a desired timing.

  FIG. 19 shows a timing chart of signals used in the control system shown in FIG. Referring to FIG. 19, as described above, the encoder signal is output from encoder element 29 shown in FIG. 18, and has a period corresponding to the moving speed of carriage 15. The edge detection circuit 32 detects the rising edge of the encoder signal and generates a reference pulse at the detection timing.

  As described above, the print timing signal is output from the print timing generation circuit 33. This print timing signal is generated in the print timing generation circuit 33 as follows. First, the print timing generation circuit 33 includes an internal pulse generation circuit 332 that generates, for example, 16 internal pulses from the rising edge of the reference pulse to the next rising edge, that is, for each period of the reference pulse. If this internal pulse is used as it is as a print timing signal, printing with a resolution of 90 dpi × 16 = 1440 dpi at maximum is possible. Further, the generation of the internal pulse enables the CPU 30 to recognize the position of the carriage 15 at a timing shorter than the generation timing of the reference pulse.

  The print timing generation circuit 33 also includes an output pulse control circuit 333 that performs control so that one print timing signal is generated every time a predetermined number of internal pulses are counted. In FIG. 19, the output pulse control circuit 333 generates one print timing signal every time two internal pulses are counted (t5, t6,...). That is, the output pulse control circuit 333 outputs a print timing signal having a resolution of 1440 dpi ÷ 2 = 720 dpi. The output pulse control circuit 333 may be configured to change the number of internal pulses that define the generation frequency of the print timing signal by inputting an appropriate selection signal.

  The print timing generation circuit 33 also includes a delay counter 334 that functions to count the internal pulses and give a print timing signal to the print head drive circuit 35 after counting a predetermined count value. That is, the delay counter 334 is set to a preset delay count value from the time (t4) when the first reference pulse is input after the time point (t3) when the start signal instructing the start of printing becomes high level. (Delay count value is 7 in FIG. 19) counts down, and when this countdown ends (t5), it functions to give a print timing signal to the print head drive circuit 35.

  The delay count value set in the delay counter 334 described above is increased or decreased to increase the initial encoder signal after the start signal (t3) at which the start signal for instructing the start of printing becomes high level. The time interval from when the reference pulse is generated (t4) to when the first print timing signal is generated (t5) can be changed. Accordingly, by changing the time interval in each direction of the reciprocating movement of the print head 27, a shift in the relative positional relationship between the print in the forward direction and the print in the reverse direction of the print head 27 is corrected. be able to. In this embodiment, correction can be performed in units of one cycle of the internal pulse, that is, with a resolution of 1440 dpi.

  The nonvolatile memory 303 includes a correction amount memory 360 for storing a delay count value that is increased or decreased for correcting the relative positional relationship as described above. Further, the ROM 301 stores delay count values corresponding to determination pattern data for performing printing for determining print position suitability, which will be described later, and identification numbers for distinguishing a plurality of determination patterns. A correction amount table 36 (FIG. 20) is provided. Details of the correction amount table 36 will be described later.

  In the background as described above, a printing position suitability determination method according to an embodiment of the present invention will be described below. FIG. 1 schematically shows a determination pattern printed on a predetermined recording sheet according to a printing position suitability determination method according to an embodiment of the present invention. The determination pattern is a No. 1 pattern printed on a single recording sheet with line feeds sequentially. 1 to No. 9 includes nine types of determination patterns. These determination patterns gradually show the relative positional relationship between the print in the forward direction and the print in the reverse direction of the print head, as will be apparent from the description to be described later. It was obtained by printing while changing to. In FIG. 1, “No. 1” to “No. 9” function as identification symbols (identification numbers) for distinguishing a plurality of determination patterns from each other, and in the determination pattern printing process. The printing is performed in correspondence with the position of each determination pattern.

  Each determination pattern is within the print range of one line by the print head, and includes a ruled line pattern part 41 based on vertical ruled lines and a dot pattern part 42 in which a plurality of dots are distributed. 41 is formed on both sides of the dot pattern portion 42. Parts II, III, IV and V of FIG. 1 are enlarged and shown in FIGS. 2, 3, 4 and 5, respectively. In FIG. 2 and the like, dots printed by ink ejected from the print head in a dot matrix format are shown.

  In each determination pattern, both the ruled line pattern portion 41 and the dot pattern portion 42 are divided into first and second print areas 43 and 44 located via a boundary extending in the moving direction of the print head. In the dot pattern portion 42, the above-mentioned boundary is displayed by a boundary line 45 printed so as to extend in the row direction, but in the ruled line pattern portion 41, it is particularly displayed by printing. Not.

  In the ruled line pattern portion 41, the comparison pattern 46 is printed in the first print area 43 according to the bidirectional movement of the print head, and the reference pattern 47 is printed in the second print area 44 according to the one-way movement of the print head. Is done. More specifically, referring to FIG. 6, first, as shown in FIG. 6A, the first print area 43 should become the comparison pattern 46 as the print head moves in the forward direction 48. A plurality of dots 46 a are printed, and at the same time, a plurality of dots 47 a constituting the reference pattern 47 are printed in the second print area 44.

  Next, as shown in FIG. 6B, a plurality of dots 46b to be the comparison pattern 46 are printed in the first print area 43 according to the movement of the print head in the backward direction 49 as shown in FIG. The In FIG. 6 (2), ◯ indicates the dot 46a or 47a by printing in the forward direction 48 shown in FIG. 6 (1). In the comparison pattern 46 shown in FIG. 6B, the printing dots 46 a in the forward direction 48 and the printing dots 46 b in the backward direction 49 are shifted from each other, but printing in the forward direction 48 and the backward direction 49 are illustrated. When the relative positional relationship with the printing is optimal, the printing dots 46a and the printing dots 46b are completely overlapped with each other.

FIG. 2 shows a state in which the print dots 46a in the forward direction 48 and the print dots 46b in the backward direction 49 are completely overlapped with each other in the comparison pattern 46. It becomes the same pattern as the pattern 47, and a series of uniform thickness vertical ruled lines are given by both the reference pattern 47 and the comparison pattern 46.
On the other hand, FIG. 3 shows a state in which the print dot 46 a in the forward direction 48 and the print dot 46 b in the backward direction 49 are shifted in the comparison pattern 46. This state occurs when the relative positional relationship between the printing in the forward direction 48 and the printing in the backward direction 49 is inappropriate. In this state, the reference pattern 47 and the comparison pattern 46 A series of vertical ruled lines given by both sides appear as double lines or become thicker in the comparison pattern 46 portion.

  On the other hand, in the dot pattern portion 42, the reference pattern 50 is printed in the first print area 43 according to the one-way movement of the print head, and the comparison pattern 51 is printed in the second print area 44 according to the two-way movement of the print head. Printed. More specifically, referring to FIG. 7, first, as shown in FIG. 7A, the reference pattern 50 is formed in the first print area 43 in accordance with the movement of the print head in the forward direction 48. A plurality of dots 50 a are printed, and at the same time, a plurality of first groups of dots 51 a constituting a part of the comparison pattern 51 are printed in the second print area 44.

  Next, as shown in FIG. 7 (2), a plurality of second groups constituting the remaining part of the comparison pattern 51 are included in the second print area 44 as the print head moves in the backward direction 49 without making a line feed. The dots 51b are printed so as to be positioned between the dots 51a of the first group by printing in the forward direction 48. In FIG. 7 (2), ◯ indicates the dot 50a or 51a by printing in the forward direction 48 shown in FIG. 7 (1).

  FIG. 4 shows a state in which the reference pattern 50 and the comparison pattern 51 give exactly the same display. In this state, the reference pattern 47 and the comparison pattern 46 are both uniform light gray. Indications are provided, and these indications have the same density or pattern. This state occurs when the relative positional relationship between the printing in the forward direction 48 and the printing in the backward direction 49 is optimal.

  On the other hand, FIG. 5 shows a state in which the comparison pattern 51 gives a display different from the reference pattern 50. This state occurs when the relative positional relationship between the printing in the forward direction 48 and the printing in the backward direction 49 is inappropriate, and in this state, the reference pattern 50 in the comparison pattern 51 is present. A different dot distribution is produced. That is, in FIG. 5, + is shown in the second print area 44, but these + should be positioned for the second group of dots 51 b when the relative positional relationship described above is optimal. Indicates the position. As can be seen from FIG. 5, the dots 51b of the second groove are displaced from the + position. Therefore, as shown in FIG. 5, when the second group of dots 51 b is shifted, the comparison pattern 51 may have a density or pattern different from that of the reference pattern 50, and typically vertical stripes may appear.

  FIG. 8 is a flowchart showing the determination pattern printing step shown in FIG. 1 and the steps for adjusting the relative positional relationship between the forward printing and the backward printing based on the result. In the steps shown in this flowchart, for example, the operator uses the input switch 103 of the operation panel 101 provided in the inkjet printing apparatus 11 to determine whether the relative positional relationship between printing in the forward direction and printing in the backward direction of the print head is appropriate. The operation is started by performing an operation for instructing execution of a print mode for determining “.

  As described above, the determination pattern No. 1 shown in FIG. 1 to No. 9 is obtained by printing while gradually changing the relative positional relationship between printing in the forward direction and printing in the backward direction of the print head. In order to change this relative positional relationship, the delay count value set in the delay counter provided in the aforementioned print timing generation circuit 33 (FIG. 18) is increased or decreased.

  Therefore, when the determination pattern is printed in steps S1 to S9 shown in FIG. 8, the identification number No. is read from the correction amount table 36 shown in FIG. 1 to No. 9, correction amounts corresponding to each of 9 (corresponding to the number of internal pulses shown in FIG. 19) +4 to −4 are sequentially read, and the delay count value currently stored in the correction amount memory 360 of the nonvolatile memory 303 That is, the determination pattern is sequentially generated based on the determination pattern data in the ROM 301 while giving the current correction value an increase or decrease by adding these correction amounts to the delay counter 334 of the print timing generation circuit 33. Printing is performed.

However, the present invention is not limited to this, and there are various methods such as a method of changing regularly within a predetermined number of internal pulses without referring to the correction amount table. With the start of this print mode, the determination pattern is printed with the correction value of the current correction value + 4 in step S1. As a result, No. 1 shown in FIG. One determination pattern is obtained.
Next, in step S2, the current correction value +3 correction value No. 1 shown in FIG. Two determination patterns are printed. Next, in step S3, the current correction value +2 correction value No. 1 shown in FIG. 3 determination patterns are printed. Next, in step S4, the current correction value + 1 and the No. shown in FIG. 4 determination patterns are printed.

Next, in step S5, the current correction value remains as it is as shown in FIG. A determination pattern of 5 is printed. Next, in step S6, the correction value of the current correction value-1 is set to No. shown in FIG. 6 determination patterns are printed. Next, in step S7, the current correction value -2 is the correction value No. shown in FIG. 7 determination patterns are printed.
Next, in step S8, the correction value of the current correction value-3 is set to No. shown in FIG. Eight determination patterns are printed. Next, in step S9, the correction value of the current correction value-4 is set to No. shown in FIG. Nine determination patterns are printed. Note that more determination patterns may be printed with a wider range of correction values, and conversely, fewer determination patterns may be printed.

Next, in step S10, an optimum correction value is selected, and its number, ie, No. 1 to No. 9 is input by the operator through the input switch 103 of the operation panel 101. In selecting the optimum correction value, No. 1 shown in FIG. 1 to No. The determination pattern 9 is visually observed.
More specifically, first, the ruled line pattern portion 41 in each determination pattern is visually observed, and each vertical ruled line including the comparison pattern 46 and the reference pattern 47 is a single straight line having a uniform thickness. Choose. In this embodiment, no. 3 corresponds to this. 2 or No. No. 4 is also No. visually. 3 is almost indistinguishable, so the operator gets lost. If the relative positional relationship between the forward direction printing and the backward direction printing is not required to be so high, these Nos. 2 to No. Any of 4 may be selected, but if higher accuracy is required, then the dot pattern portion 42 is visually observed.

In visual observation of the dot pattern portion 42, in particular, No. 2 to No. 4 is visually observed, and the reference pattern 50 and the comparison pattern 51 are selected so as to give the same display. In this embodiment, no. 3 corresponds to this. Thus, in step S10, the optimum correction value number No. 3 is selected and specified by the operator.
When designated in this way, in step S11, the selected number No. The correction value corresponding to 3 is added to the correction amount currently stored in the correction amount memory 360, stored as a new correction amount in the correction amount memory 360, and also set in the delay counter 334. Based on this, the print position of the print head in both directions is corrected. The correction amount stored in the correction amount memory 360 becomes a reference for the print start timing in future printing.

  In the embodiment as described above, the comparison pattern 46 or 51 and the reference pattern are used in both the ruled line pattern portion 41 and the dot pattern portion 42 in order to determine whether or not the relative positional relationship between the forward direction printing and the backward direction printing is appropriate. A relative comparison with 47 or 50 is made. Since the human eye can make a finer determination by performing a relative comparison than by an absolute determination, it can be said that according to this embodiment, a more accurate and reliable determination can be made in this respect.

  In this regard, in the above-described embodiment, the first print area 43 on which the comparison pattern 46 or the reference pattern 50 is printed and the second print area 44 on which the reference pattern 47 or the comparison pattern 51 is printed have a space. Since they are positioned adjacent to each other without being separated, each comparison between the comparison patterns 46 and 51 and the reference patterns 47 and 50 can be performed within a narrow field of view. This makes it possible to make accurate judgments.

  In addition, the comparison pattern 46 in the ruled line pattern portion 41 in this embodiment is printed with a thicker or double line than the reference pattern 47 when the relative positional relationship is inappropriate. Both can be easily compared. In addition, in this embodiment, since the reference pattern 47 and the comparison pattern 46 should both provide a series of vertical ruled lines, when the relative positional relationship is appropriate, the reference pattern 47 and the comparison pattern 46 A vertical ruled line having a uniform thickness appears on both sides. On the other hand, when the relative positional relationship is inappropriate, only a portion corresponding to the comparison pattern 46 in the vertical ruled line appears thick or a double line appears. Therefore, it is possible to easily and without error determine the suitability of the relative positional relationship.

  According to this embodiment, in the printing process, the reference patterns 47 and 50 and a part of each of the comparison patterns 46 and 51 are printed according to the one-way movement of the print head, and the comparison is performed according to the other-direction movement of the print head. Since the remaining portions of the patterns 46 and 51 are printed, both the reference patterns 47 and 50 and the comparison patterns 46 and 51 can be printed by one reciprocation of the print head. Therefore, it is possible to efficiently perform printing for determining the suitability of the printing position.

  In this embodiment, since the ruled line pattern portion 41 and the dot pattern portion 42 are used in combination for the determination, the respective characteristics can be utilized, and also in this respect, the determination is more accurate and error-free. Can be performed. In this embodiment, as described above, the rough determination is first performed by visual inspection of the ruled line pattern portion 41, and then the final determination is performed by visual inspection of the dot pattern portion 42. This has the following significance. There is. That is, the comparison pattern 51 of the dot pattern portion 42 shows a display that is equal to the reference pattern 50 when the deviation between the dots of the first group and the dots of the second group becomes large and reaches a certain size. There is a time to give. Therefore, when only the dot pattern portion 42 is viewed, this state may be erroneously determined to be optimal. On the other hand, in the ruled line pattern portion 41, such an inconvenience does not usually occur. Therefore, it is meaningful to first make a rough determination by visually checking the ruled line pattern portion 41.

Further, in this embodiment, the ruled line pattern portion 41 and the dot pattern portion 42 as described above are contained within one line for each determination pattern, so that the printing area can be saved. Therefore, the recording paper can be saved. In addition, a large number of determination patterns can be printed on one recording sheet.
In addition, since the reference pattern 50 and the comparison pattern 51 in the dot pattern portion 42 in this embodiment are each configured by distributing a plurality of dots, the comparison between the reference pattern 50 and the comparison pattern 51 is as follows. Since the entire display on a surface having a predetermined area is compared, visual determination can be performed with high accuracy. Further, since the reference pattern 50 and the comparison pattern 51 are compared with the entire display on the surface having the predetermined area in this way, even if the movement speed of the print head fluctuates, it is determined without difficulty. can do.

  Further, in this embodiment, when the print head is inclined with respect to the moving direction, in the ruled line pattern portion 41, as shown in FIG. 10, the comparison pattern 46 and the reference pattern 47 are in the row direction. It may be tilted and printed. However, according to this embodiment, even in the above-described case, the comparison pattern 46 and the reference pattern 47 are inclined in the same direction at the same angle, and the ruled line 52 by the forward printing in the comparison pattern 46 and the backward printing are performed. The ruled line 53 is only inclined at the same angle in the same direction.

  Therefore, the comparison between the comparison pattern 46 and the reference pattern 47 is not hindered, and the comparison between the comparison pattern 46 and the reference pattern 47 is performed as in the case where the print head does not tilt as described above. Can do. Further, in this embodiment, when the head surface of the print head and the recording surface are not parallel, the ruled line pattern portion 41 has the ruled line 52 by the forward printing of the comparison pattern 46 and the ruled line 53 by the backward printing reversed. 11, the comparison pattern 46 is printed in a V-shape as shown in FIG. 11. Therefore, the comparison pattern 46 and the reference pattern 47 may form a y-shaped pattern. However, even in this case, it is not impossible to compare the line thicknesses of the upper and lower comparison patterns 46 and the reference pattern 47, and therefore an appropriate adjustment value can be selected.

  Each state shown in FIG. 10 and FIG. 11 is relatively extremely illustrated for convenience of explanation. In practice, the comparison pattern 46 and the reference pattern 47 are inclined as shown in FIG. As shown in FIG. 11, the y-shape does not appear clearly. Therefore, for example, even if the comparison pattern 46 and the reference pattern 47 are printed in the manner shown in FIG. 11, the upper end of the y-character does not open extremely as shown in FIG. It is not impossible to compare the thickness of the line with the reference pattern 47. As shown in FIG. 11, if the upper end of the y-shape is extremely open, it is a completely defective product, which is a problem before the print position adjustment, and cannot be at the actual product level.

  In this embodiment, the operator operates the input switch 103 provided on the operation panel 101 provided in the inkjet printing apparatus 11 to increase / decrease the determination pattern data stored in the ROM 301 and the correction amount. The data to be represented is used to print the determination pattern, and input for instructing an appropriate correction value thereafter is performed. However, the present invention is not limited to this, and the following may be used.

  For example, by using the external electronic device 200 capable of transmitting and receiving data through the communication interface 100 shown in FIG. 17, the operator can transfer and correct determination pattern printing instructions and determination pattern data as described above. You may make it instruct | indicate the quantity. In this case as well, various modifications are conceivable. As the external electronic device 200, a personal computer (hereinafter referred to as a PC) is taken as an example.

  As is generally known, software called a driver having a function of sending and controlling data to a device connected to the device is run on the PC. If this driver uses a printer, it converts the data created by various applications running on the PC into data that can be printed and sends it to the printer, or the printer has A control code for remotely controlling various functions from a location away from the printer main body is transmitted.

  Also in the present embodiment, the operator may print the determination pattern and input the subsequent correction amount by using such a driver (printer driver) on the PC. In this case, the following operations are generally performed. First, the operator activates a driver on the PC, selects a printer setting screen with the printer driver, selects an item for print timing correction from the screen, and executes it.

  Then, the printer driver first sends a dedicated control command to instruct the printer, that is, the inkjet printing apparatus 11 to enter the print timing correction mode. Subsequently, the determination pattern data stored in the storage unit of the PC and the control code for instructing to shift the printing timing by a predetermined amount when the pattern is reciprocated by the carriage, the identification code corresponding to the data indicating the deviation amount at that time are displayed. The print data is sent to the ink jet printer 11 while changing the required number of deviations together with the print data.

  The ink jet printing apparatus 11 receives these data, performs printing in the same manner as shown in the flow of FIG. 8, and waits for a correction amount instruction. At this time, the printer driver has a screen display for receiving the input of the number corresponding to the correction amount after the transmission of the data such as the determination pattern. The operator selects an optimum one based on the printed determination pattern and inputs the identification symbol at a predetermined position on this screen. At this time, the printer driver checks the input value based on the allowable input value range. If the input value is out of range, an error is displayed and input is prompted again.

  If the input value is within the predetermined range, the printer driver instructs the inkjet printing apparatus 11 to update the correction amount memory currently set and the delay counter based on the value corresponding to the identification symbol and the value. A control command for instructing resetting is sent, and this print timing correction mode is terminated. The ink jet printing apparatus 11 receives this control code, updates the correction amount memory and resets the delay counter in the same manner as described above, ends the print timing correction mode, and prepares for subsequent printing.

  In the above description, the determination pattern is shown to be visually observed by the operator. However, the present invention is not limited to this. Recently, there is an apparatus that not only has a function of printing print data given from an external electronic device, but also includes an image reading apparatus (image scanner) in the printing apparatus and has a copy function and an image reading function. The ink jet printing apparatus 11 according to the present embodiment also includes an image reading unit 400 as shown in the block diagram of FIG. If the image reading unit 400 has a resolution equivalent to the resolution of the printing unit determined by the print head or the like, first, the ruled line pattern unit 41 performs a rough determination as described above, and then the dot pattern unit. The determination work of performing the final determination by 42 can be automated.

Hereinafter, the automatic determination process using the image reading unit 400 will be described with reference to the flowchart of FIG. As described above, the process shown in the flowchart is a process performed by the image reading unit 400 provided in the apparatus that has performed printing after the determination pattern is printed.
First, the operator indicates that the operation is not a normal image reading operation, and sets the determination mode to be entered using the input switch 103 of the operation panel 101 (S20), and the image reading unit 400 reads the sheet on which the determination pattern is printed. (S22), and the determination pattern is read. The image reading unit 400 reads the pattern printed for each identification number under the control of the CPU 30, and stores it in the RAM 302 in a form that can be read for each identification number later (S24). At this time, a bar code notation is also written in the identification number so that the CPU 30 can be easily associated with the pattern.

  Next, with respect to the determination pattern for each read identification number, the comparison pattern portion and the reference pattern portion are compared. First, the first pattern portion is determined based on the first comparison criterion. For example, focusing on the shift in the scanning direction of the upper and lower patterns for the ruled line pattern portion, the difference (average value) is obtained for the patterns corresponding to all the identification symbols, and the difference is evaluated (S26). ).

  If the difference is clearly the lowest compared to other differences, that is, if two or more differences are not within the predetermined range (YES in S28), the one with the identification number having the difference is optimal. Therefore, the process proceeds to the correction amount setting process. If there is no optimum one (NO in S28), the one having a deviation amount within a predetermined range is selected (S30), and the second pattern portion is determined (S32).

  At this time, the comparison may be performed using a second comparison criterion different from the first comparison criterion. For example, the dot pattern portion 42 is a pattern suitable for comparing the density difference between the comparison pattern portion and the reference pattern portion, rather than detecting the shift amount. In general, the printed dots are not ideal so that printing and non-printing of dots represented by 1 and 0 have the same size and shape, and the printed one has a certain spread. There is a tendency to end up. Therefore, even if the same number of dots are printed per unit area, depending on the dot printing location (distance between dots), that is, the proximity of multiple dots, the spread of each other is regulated and the density differs. Will occur. The dot pattern portion 42 of the present embodiment takes into account such characteristics when printing these dots, slightly shifts the printing timing for each determination pattern, and provides some fluctuation between the printed dots. There is.

  On the other hand, the image reading unit 400 includes an A / D converter that converts an input optical signal into a digital value, and the read value is a gray signal having multiple levels of information per dot according to the resolution. It can be entered. Therefore, when the determination pattern is read, each pattern is read as a gray signal into the RAM 302, and when comparing the dot pattern portion 42, an average density of a predetermined area between each comparison pattern and the reference pattern may be obtained. .

  In this way, also in the second pattern portion, the comparison is performed based on the difference between the comparison pattern portion and the reference pattern portion (S32), and the optimum one is determined in the same manner as in the first pattern portion. Here, when all the differences fall within the predetermined range and the optimum one cannot be selected (NO in S34), the current correction amount is read from the correction amount memory in the nonvolatile memory 303 and is close to the value. Select one of the things.

  In accordance with the identification number selected in this way, the correction amount memory is updated, the delay counter is reset (S38), the print timing correction processing mode is finished (S40), and the normal standby state is restored. In step S38, an identification number indicating the correction amount to be updated is displayed on the display unit 102 on the operation panel 101, and the operator confirms the identification number. Then, the updating process is performed by a confirmation instruction on the input switch 103 thereafter. It may be.

  Furthermore, in each step of S26 and S32 of the above-described flow, the value read by the image scanner unit is also used as the reference pattern for comparison. However, the pattern is not limited to this and is used for pattern printing in the inkjet printing apparatus 11. Therefore, the pattern data held for this purpose may be used as a reference. Further, the candidates may be narrowed down by the comparison of the dot pattern portions 42 and determined in the ruled line pattern portion 41.

  FIG. 12 is for explaining another embodiment of the present invention, and shows an enlarged ruled line pattern portion 61 corresponding to the ruled line pattern portion 41 in the above-described embodiment. Also in this embodiment, the comparison pattern 62 is printed in the first print area 43 according to the bidirectional movement of the print head, and the reference pattern 63 is printed in the second print area 44 according to the one-way movement of the print head. Is done. A feature of this embodiment is that, in printing the reference pattern 63, the first and second colors which are different from each other are overlaid in accordance with the one-way movement of the print head, and the comparison pattern 62 is printed. The first color printing is performed when the print head moves in the forward direction, and the second color printing is performed when the print head moves in the backward direction.

  More specifically, first, as the print head moves in the forward direction, a plurality of dots 62a to be the comparison pattern 62 are printed with cyan, for example, in the first print area 43, as indicated by ●, and simultaneously In the second print area 44, as indicated by ◎, a plurality of dots 63a constituting the reference pattern 63 are printed, for example, by superimposing cyan and magenta. Next, as indicated by a circle, a plurality of dots 62b to be the comparison pattern 62 are printed with magenta, for example, in the first print area 43 according to the backward movement of the print head without causing a line feed.

  Contrary to the use of the color described above, the dot 62a by forward printing to be the comparison pattern 62 may be given with magenta, and the dot 62b by backward printing may be given with cyan. In the comparison pattern 62 shown in FIG. 12, the print dot 62a in the forward direction and the print dot 62b in the reverse direction are shifted. This state occurs when the relative positional relationship between the forward direction printing and the backward direction printing is inappropriate. In this state, the comparison pattern 62 and the reference pattern are the same as in the above-described embodiment. A series of vertical ruled lines given by both of the patterns 63 appear not only as double lines and become thicker in the comparison pattern 62 portion, but also each color of cyan and magenta in the comparison pattern 62 portion. Are recognized separately. On the other hand, in the reference pattern 63 portion, a color in which the cyan and magenta colors overlap is recognized.

  On the other hand, when the relative positional relationship between the printing in the forward direction and the printing in the backward direction is optimal, in the comparison pattern 62, the print dots 62a in the forward direction and the print dots 62b in the backward direction are completely mutually different. Overlapping state. In this state, both the comparison pattern 62 and the reference pattern 63 provide not only a series of uniform thickness vertical ruled lines, but also cyan and magenta in both the comparison pattern 62 and the reference pattern 63. Overlapping colors are recognized.

  Therefore, according to this embodiment, it is possible to determine whether or not the relative positional relationship between forward printing and backward printing is appropriate based on the color difference between the comparison pattern 62 and the reference pattern 63. Accuracy and reliability can be improved. In the above embodiment, a combination of cyan and magenta is used. This combination has the advantage that it is easier to recognize both single and mixed colors compared to combinations containing other colors, i.e. yellow or black, but if such an advantage is not desired Other color combinations may be used.

  FIG. 13 is a view for explaining still another embodiment of the present invention, and shows a reference pattern 71 and a comparison pattern 72 with an enlarged view corresponding to FIG. 2 described above. Also in this embodiment, two colors are used in printing, as in the embodiment shown in FIG. 12 described above. In this embodiment, in printing the reference pattern 71, the first different from each other according to the one-way movement of the print head. The second color and the second color are printed adjacent to each other. In the comparison pattern 72, the first color is printed when the print head moves in the forward direction, and the second color is printed. It is characterized in that it is performed when the head moves in the backward direction.

  More specifically, first, in accordance with the movement of the print head in the forward direction, the first print area 43 includes a first group of dots 71a indicated by a circle constituting a reference pattern 71 and a second group indicated by a circle. The dots 71b are printed together, and at the same time, in the second print area 44, the first group of dots 72a indicated by a circle constituting a part of the comparison pattern 72 is printed. Next, the second group of dots 72b indicated by ● constituting the remainder of the comparison pattern 72 is printed in the second print area 44 in accordance with the backward movement of the print head without causing a line feed.

  The first group of dots 71a and the second group of dots 71b in the reference pattern 71 described above are adjacent to each other and are printed in different colors. The first group dot 72a in the comparison pattern 72 is printed with the same color as the color of the first group dot 71a in the reference pattern 71, and the first color in the comparison pattern 72 with the same color as the color of the second group dot 71b. Two groups of dots 72b are printed.

  As a combination of these colors, for example, a combination of cyan and magenta is used. The comparison pattern 72 shown in FIG. 13 gives the same display as the reference pattern 71. That is, the comparison pattern 72 has a state in which the first color and the second color are adjacent to each other in the same manner as the reference pattern 71. This display is obtained when the relative positional relationship between the printing in the forward direction and the printing in the backward direction is appropriate.

  On the other hand, when the relative positional relationship between the forward direction printing and the backward direction printing is inappropriate, in the comparison pattern 72, the first group of dots 72a printed in the first color and the second color are printed. A state in which the second group of dots 72b overlaps at least partially, or the distance between the first group of dots 72a and the second group of dots 72b differs from the corresponding distance in the reference pattern 71 appears.

Accordingly, it is possible to determine whether or not the relative positional relationship between the forward printing and the backward printing of the print head is appropriate based on a difference in color between the reference pattern 71 and the comparison pattern 72 or a difference in color mixing. Thus, the accuracy and reliability of judgment can be improved. In the above-described embodiment, other color combinations may be used.
Also, in the dot pattern portion 42 shown in FIG. 1 and the like, printing with two colors as described with reference to FIG. 13 may be employed. This will be described with reference to FIG. 7. First, as shown in FIG. 7 (1), in accordance with the movement of the print head in the forward direction 48, the first print area 43 includes a plurality of reference patterns 50. The dots 50a are printed, but at this time, the dots 50a are printed with the first color or the second color different from each other, and printed with the first color and the second color. Are made adjacent to each other. At the same time, in the second print area 44, a plurality of first groups of dots 51a constituting a part of the comparison pattern 51 are printed, for example, in the first color. Next, as shown in FIG. 7 (2), a plurality of second groups constituting the remaining part of the comparison pattern 51 are included in the second print area 44 as the print head moves in the backward direction 49 without making a line feed. The dots 51b are printed in the second color so as to be positioned between the dots 51a of the first group by printing in the forward direction 48.

14 and 15 show still another embodiment of the present invention. In each of the embodiments described above, the print area on which the reference pattern is printed and the print area on which the comparison pattern is printed are located via a boundary extending in the movement direction of the print head. May be modified as shown in FIG. 14 or FIG.
In FIG. 14, the print area 81 on which the reference pattern is printed and the print area 82 on which the comparison pattern is printed are positioned so as to be aligned in a line in the movement direction of the print head. In particular, in this embodiment, a plurality of print areas 81 for printing the reference pattern and a plurality of print areas 82 for printing the comparison pattern are alternately arranged. In FIG. 15, the print area 81 on which the reference pattern is printed and the print area 82 on which the comparison pattern is printed are arranged not only in the moving direction of the print head but also in two lines. The print head is positioned via a boundary extending in the moving direction of the print head. That is, the print area 81 on which the reference pattern is printed and the print area 82 on which the comparison pattern is printed are arranged so as to be aligned in the direction of movement of the print head and also in the direction orthogonal to the movement direction.

  In particular, according to the arrangement of the print areas 81 and 82 shown in FIG. 15, since the comparison can be made both in the vertical direction and in the horizontal direction, even if the difference between the reference pattern and the comparison pattern is small, Can be easily identified visually, and the accuracy of determination can be further increased. As shown in FIGS. 14 and 15, even if the positional relationship between the print area 81 on which the reference pattern is printed and the print area 82 on which the comparison pattern is printed is changed, the print areas 81 and 82 are adjacent to each other. As long as this is done, it does not prevent easy comparison between the reference pattern and the comparison pattern.

  The reference patterns and comparison patterns printed in the print areas 81 and 82 are the reference patterns 47 or 50 and the comparison patterns 46 and 51 shown in FIG. 1 and the like, the reference pattern 63 and the comparison pattern shown in FIG. A pattern such as the pattern 62, the reference pattern 71 and the comparison pattern 72 shown in FIG. 13, or other patterns can be applied.

  Although the present invention has been described with reference to the illustrated embodiment, other embodiments are possible within the scope of the present invention. For example, in the embodiment described with reference to FIG. 1 and the like, the determination pattern includes the ruled line pattern unit 41 based on vertical ruled lines and the dot pattern unit 42 in which a plurality of dots are distributed. Either one of the pattern portion or the dot pattern portion may be omitted, and the determination may be performed using only one of them.

  Further, regarding the ruled line pattern portion 41, in the above-described embodiment, the reference pattern 47 and the comparison pattern 46 should both give a series of vertical ruled lines. However, the relative positional relationship of the comparison pattern is optimal. In some cases, it is sufficient that the portion printed according to the forward movement of the print head and the portion printed according to the backward movement of the print head overlap each other. Embodiments that do not provide a series of vertical ruled lines are possible. Even if the reference pattern and the comparison pattern are given with a pattern other than the vertical ruled line, the comparison pattern can be compared with the reference pattern by appearing in the comparison pattern with a thickness or double line different from the reference pattern as in the case of the vertical ruled line. Is possible.

  Further, when a plurality of vertical ruled lines are arranged in the ruled line pattern unit 41, the arrangement density of these vertical ruled lines can be arbitrarily changed. Also, with regard to the dot pattern portion 42, a dot distribution state different from the illustrated form may be employed. In the illustrated embodiment, the first printing area 43 on which the comparison pattern 46 and the reference pattern 50 are printed and the second printing area 44 on which the reference pattern 47 and the comparison pattern 51 are printed are substantially equal to each other. Although it has an area, the areas of the first and second print regions may be different from each other.

  In the illustrated embodiment, the comparison pattern 46 and the reference pattern 50 are printed in the first print area 43, and the reference pattern 47 and the comparison pattern 51 are printed in the second print area 44. The print area where 46 and the reference pattern 47 are printed may be reversed, or the print area where the reference pattern 50 and the comparison pattern 51 are printed may be reversed.

  In the illustrated embodiment, the reference patterns 47 and 50 are printed by the forward printing of the print head, and at the same time, each part of the comparison patterns 46 and 51 is printed, and the backward printing without a line feed is performed. Although the remaining portions of the comparison patterns 46 and 51 are printed, the printing procedure can be arbitrarily changed. For example, the reference patterns 47 and 50 may be printed in the backward direction of the print head. Further, as long as the comparison pattern is printed according to the bidirectional movement of the print head, a line feed operation may be performed between the comparison pattern printing and the reference pattern printing.

  In the embodiment described above, according to the flow shown in FIG. 8, as shown in FIG. 1 to No. 9 is printed all at once, and then these determination pattern Nos. 1 to No. 9, the reference pattern 47 and 50 and the comparison pattern 46 and 51 are most approximated, and with the adjustment value corresponding to the selected determination pattern, the forward printing and the backward printing are performed. However, instead of this procedure, the determination pattern is printed in the current state, the relative positional relationship is corrected based on the determination pattern, and the determination pattern based on the corrected relative positional relationship is corrected. It is also possible to obtain the optimum relative positional relationship by repeating printing and correction trials such as printing, and correction of relative positional relationship based on the printing.

  In the above-described embodiment, the relative positional relationship between the forward printing and the backward printing is adjusted by changing the timing delay amount from the start of movement of the print head to the start of printing. The method for such adjustment can be arbitrarily changed. In the above-described embodiment, the inkjet head is intended as the print head. However, the print position suitability determination method according to the present invention is a print head that reciprocates and performs printing in both reciprocating directions. It can be applied to printing by any print head. For example, in the case of a wire dot type print head, a gap is always formed between the head surface and the recording paper surface as in the case of the ink jet head, so the printing start time on the printing head and the printing completion time on the recording paper. For this reason, the relative positional relationship between the forward printing and the backward printing may be deviated, and the printing position suitability determining method according to the present invention is advantageously applied. Even with a thermal head or an electrophotographic head, there is a delay in electrical signal transmission and processing, so the present invention can be advantageously applied.

FIG. 3 is a diagram schematically showing a plurality of determination patterns printed on a predetermined recording sheet according to a printing position suitability determination method according to an embodiment of the present invention. It is an enlarged view of the part II of FIG. It is an enlarged view of the part III of FIG. It is an enlarged view of the part IV of FIG. It is an enlarged view of the part V of FIG. FIG. 3 is a diagram corresponding to FIG. 2 for explaining a printing procedure of a comparison pattern 46 and a reference pattern 47 in the ruled line pattern portion 41 shown in FIG. FIG. 5 is a view corresponding to FIG. 4 for explaining a printing procedure of the reference pattern 50 and the comparison pattern 51 in the dot pattern portion 42 shown in FIG. 1. FIG. 2 is a flowchart showing printing steps of a determination pattern shown in FIG. 1 and steps for adjusting a relative positional relationship between forward printing and backward printing from the result. It is a flowchart which shows the step of the automatic determination process using an image reading part. In the embodiment shown in FIG. 1, it is a figure which shows the printing result of the ruled line pattern part 41 in case the print head inclines with respect to the moving direction. In the embodiment shown in FIG. 1, it is a figure which shows the printing result of the ruled line pattern part 41 in case the head surface of a printing head and a recording surface are not parallel, schematically. It is a figure equivalent to FIG. 2 for demonstrating other embodiment of this invention. It is a figure equivalent to FIG. 2 for demonstrating other embodiment of this invention. It is a figure which shows the arrangement | positioning aspect of the printing area | regions 81 and 82 for describing other embodiment of this invention illustratively. It is a figure which shows the arrangement | positioning aspect of the printing area | regions 81 and 82 for describing other embodiment of this invention illustratively. 1 is a perspective view showing a main part of a printing apparatus 11 including an ink jet type print head 27 of interest to the present invention. It is a block diagram for demonstrating the control system in the printing apparatus 11 shown in FIG. It is a block diagram for demonstrating further part of the control system in the printing apparatus 11 shown in FIG. FIG. 19 is a timing diagram of signals used in the control system shown in FIG. 18. It is a figure which shows the correction amount table 36 stored in the correction amount memory with which the printing timing generation circuit 33 shown in FIG. 18 is equipped. FIG. 6 is a diagram schematically showing vertical ruled lines 1, 5, and 7 as determination patterns printed on a predetermined recording sheet according to a conventional print position suitability determination method. FIG. 22 is a diagram schematically showing the printing results of the vertical ruled lines 1, 5 and 7 shown in FIG. 21 when the print head is inclined with respect to its moving direction. It is a figure which shows the printing result of the vertical ruled lines 1, 5 and 7 shown in FIG. 21 when the head surface and recording surface of a print head are not parallel. FIG. 22 is a diagram schematically showing the print results of the vertical ruled lines 1, 5 and 7 shown in FIG. 21 when the moving speed of the print head varies.

Explanation of symbols

11 Inkjet printing device 15 Carriage 18 Recording paper 26 Carriage drive motor 27 Print head 30 CPU
33 Print timing generation circuit 35 Print head drive circuit 36 Correction amount table 41, 61 Ruled line pattern part 42 Dot pattern part 43, 44, 81, 82 Print area 45 Border line 46, 51, 62, 72 Comparison pattern 47, 50, 63 71 Reference pattern 46a, 46b, 47a, 50a, 51a, 51b, 62a, 62b, 63a, 71a, 71b, 72a, 72b Print dot 48 Forward direction 49 Reverse direction

Claims (8)

When a reciprocating print head performs printing in both reciprocating directions, it is a method for determining the suitability of the relative positional relationship between printing in the forward direction and printing in the reverse direction on a recording paper,
Of the two adjacent print areas on the recording paper, one of the print areas is printed with a reference pattern according to one-way movement of the print head, and the other print area is printed with the reference pattern according to two-way movement of the print head. A printing process for printing a comparison pattern to be the same pattern as
A step of comparing the comparison pattern with the reference pattern to determine whether or not both are equal, and determining that the relative positional relationship is appropriate when both are determined to be equal;
The comparison pattern includes a pattern in which the portion printed according to the forward movement of the print head and the portion printed according to the backward movement of the print head completely overlap each other when the relative positional relationship is optimal. A printing position suitability determination method characterized in that printing is performed with a thicker or double line than the reference pattern when the target positional relationship is inappropriate.   The printing position suitability determination method according to claim 1, wherein the reference pattern and the comparison pattern should be provided with a series of vertical ruled lines.   In the printing step, both the first and second printing areas are within the printing range of one line by the print head, and the comparison pattern is obtained by bi-directionally moving the print head without a line feed. The printing position suitability determination method according to claim 1, wherein printing is performed.   In the printing step, the reference pattern and a part of the comparison pattern are printed according to the one-way movement of the print head, and the remaining part of the comparison pattern is printed according to the other-direction movement of the print head. The printing position suitability determination method according to claim 3.   5. The printing position suitability determination method according to claim 1, wherein a set of a plurality of types of the reference pattern and the comparison pattern is printed in the printing step.   6. The print area on which the reference pattern is printed and the print area on which the comparison pattern is printed are located via a boundary extending in the movement direction of the print head. The printing position suitability determination method described in 1.   The print area on which the reference pattern is printed and the print area on which the comparison pattern is printed are positioned so as to be aligned in the moving direction of the print head. Of printing position suitability. A printing device in which a reciprocating print head prints in both reciprocating directions,
When execution of printing for determining the print position suitability is instructed, the reference pattern is printed in one of the two print areas adjacent to each other on the recording paper according to the one-way movement of the print head, and the other print In the area, printing means for printing a comparison pattern that should be the same pattern as the reference pattern according to the bidirectional movement of the print head;
Comparing the comparison pattern with the reference pattern to determine whether or not they are equal to each other, and comprising determining means for determining that the relative positional relationship is appropriate when both are equal.
The comparison pattern includes a pattern in which the portion printed according to the forward movement of the print head and the portion printed according to the backward movement of the print head completely overlap each other when the relative positional relationship is optimal. A printing apparatus, wherein when the target positional relationship is inappropriate, printing is performed with a thicker or double line than the reference pattern.

Images