JP2000177175A - Interlace type printer and interlace type printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lowering of image quality which may occur when dots on the identical dot line are printed straight by utilizing a simple means or method in the case where the printing is executed by an interlace method. SOLUTION: A plurality of dot forming elements are formed from a plurality of dot forming element groups (NZGA, NZGB) each of which is a single group of a predetermined number of continuous dot forming elements. A medium conveying mechanism control section drives a medium conveying mechanism 14 such that all of the dots in one dot row in a print image are formed from the dot forming elements in one dot forming element groups. A print head control section 15 drives a print head such that the dot forming element groups (NZGA, NZGB) form each specific dot row of a dot row group in the dot row groups consisting of dot rows which are disposed discretely in a subs-scanning direction according to movement of a carriage 12, the number of dot row groups being the same as that of dot forming element groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlaced printing technique, and more particularly to a printer and a printing method capable of eliminating unevenness of a printout image caused by a transport error of a print medium (hereinafter, simply referred to as "medium"). About the method.

[0002]

2. Description of the Related Art In recent years, printers tend to have higher resolution regardless of the print format. In a dot-impact printer (dot-impact printer), the interval between pins arranged on the print head is reduced, and in an ink-jet printer (ink-jet printer), the interval between nozzles arranged on the print head is reduced. By reducing the size, the resolution can be increased.

However, in these printers, there is a limit in reducing a pin interval or a nozzle interval due to a problem in mechanism. The normal printing method, that is, the dot row (in this specification, the arrangement of the dots in the main scanning direction) is used.
In the method of printing in the order of adjacency, that is, in the order of dot rows, the resolution is the same as the arrangement density of pins and nozzles, ie, 60 dpi (dot) in a dot impact printer.
per inch), and an ink jet printer can only obtain a resolution of about 180 dpi.

[0004] For this reason, in the dot impact printer and the ink jet printer, printing by the interlace method is performed in order to increase the resolution. FIG. 10 is an explanatory diagram illustrating an outline of the inkjet printer 6 that performs printing in the interlaced mode. The printer 6 includes a print head 61 as a mechanical system.
And a carriage 62 on which the print head 61 is mounted.
And a carriage drive mechanism 63 for moving the carriage 62, and a medium transport mechanism 64. The control system includes a printhead control section 65, a carriage drive mechanism control section 66, and a medium transport mechanism control section 67. And an image analysis processor 68.

In FIG. 10, a medium transport mechanism 64 includes a medium transport roller 641, a stepping motor 642,
It includes a plurality of gear groups 644 interposed between them. The driving force of the stepping motor 642 is transmitted to the medium transport roller 641 via a gear group 644, and the medium transport roller 641 sandwiches the medium 200 between the medium 200 and the auxiliary medium transport roller 643, and in the sub-scanning direction (y direction). ) In a predetermined pitch unit.

The carriage driving mechanism 63 includes a timing belt 631, a motor (not shown), a pulley 6
32. The pulley 632 is connected to the carriage 62
The shaft is rotatably mounted on the
The carriage 62 can reciprocate in the main scanning direction (± x direction) via the pulley 632 by receiving a driving force from a motor (not shown).

In the printer 6 shown in FIG. 10, a print head 61 has fifteen nozzles NZ _{1 to} NZ (not shown).
₁₅ is 180 d in the sub-scanning direction (the conveying direction of the medium 200).
pi (that is, at an interval of 1/180 inch). Since the resolution of the printer is usually expressed in dpi, it is convenient to express the distance between nozzles, the conveyance distance of the medium 200, and the like in “inch”. Therefore,
In this specification, "inch" is used as a unit of length.

When printing is performed so that the resolution in the sub-scanning direction is 720 dpi, the medium transport mechanism controller 6
Reference numeral 7 designates a value corresponding to one pitch feed (1/48)
0 inch), and the medium transport mechanism 64 rotates the stepping motor 642 by an amount corresponding to the pitch feed amount data PTD at a predetermined timing. Thereby, the medium transport roller 64
No. 2 conveys the medium 200 by one pitch feed. The carriage driving mechanism 63 moves the carriage 62 in the main scanning direction during the period when the conveyance of the medium 200 is stopped, and the print head 61 moves the ink droplets from predetermined nozzles based on a control signal from the print head controller 65. Fire,
Perform printing.

FIGS. 11A and 11B are diagrams for explaining the principle of printing by the conventional interlace method. Here, for convenience of explanation, it is shown that the medium 200 is stationary and the print head 61 is moving. FIG.
In (A), during conveyance stop period of the medium 200, the ink droplets from the nozzle NZ ₁ ~NZ _15, the dripping position on principle, are shown in black squares. FIG. 11B
So during conveyance stop period after one pitch feed of the medium 200, the ink droplets from the nozzle NZ ₁ ~NZ _15, dripping position on principle, it is shown in black triangles. For easy understanding, in FIGS. 11A and 11B, white squares are also arranged at portions other than the black squares and the black triangles. As described above, by successively feeding ink droplets onto the medium 200 with four consecutive pitch feeds, printing can be performed at a resolution of 720 dpi, which is four times the nozzle density of 180 dpi in the sub-scanning direction.

[0010]

However, due to the eccentricity of the rotation shaft of the medium conveying roller 641 and the gear group 644, the conveying distance of the medium 200 by one pitch by the medium conveying mechanism 64 is originally planned. Is different from the distance
In some cases, dot intervals in the sub-scanning direction may not be equal. It is expected that the error of the dot interval usually appears periodically with respect to the transmission of the pitch feed amount data PTD.

Particularly, in the above-described interlaced high-resolution printer, dots belonging to the same dot row are formed in a straight line by the same dot forming element (nozzle). For this reason, due to the deviation of the ink droplet landing position from the original position, the printed image has a band pattern (light-colored stripe pattern or banding) called banding, as described later with reference to FIGS. (Unevenness due to dark stripes).

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. An object of the present invention is to provide a simple means or method for printing dots belonging to the same dot row on a straight line when printing is performed by an interlace method. It is an object of the present invention to provide an interlaced printer and an interlaced printing method capable of preventing or improving the deterioration of image quality caused by printing.

[0013]

The present inventor has determined that the above-mentioned banding is performed because all dots belonging to the same dot row are formed with the same error. If formed by the dot forming elements, banding can be mitigated. Further, among the dot rows in the main scanning direction, in each row group in which a plurality of continuous rows constitute one group, each row is arranged in a different order from the arrangement order of the dot rows. The present invention has been made based on the knowledge that the above-described pitch feed amount error can be reduced by forming the dot rows, thereby preventing the banding from occurring.

The interlaced printer of the present invention (hereinafter simply referred to as “printer of the present invention”) is a dot impact type or ink jet type printer.
As with conventional interlaced printers, print heads, carriages, carriage drive mechanisms, media transport mechanisms,
It has a print head controller, a carriage drive mechanism controller, and a medium transport mechanism controller.

In the print head, dot forming elements (pins and nozzles) are arranged at predetermined intervals in the sub-scanning direction. The print head is mounted on the carriage,
The carriage drive mechanism control unit controls the carriage drive mechanism,
The carriage driving mechanism sends a reciprocating timing signal and the like, and the carriage driving mechanism reciprocates the carriage in the main scanning direction.

The print head controller drives the print head in accordance with the reciprocation of the carriage in the main scanning direction, and causes a predetermined dot forming element to form a dot row in the main scanning direction. Note that the “formation of a dot row” here includes formation of a blank row (that is, not driving the dot forming element over the entire dot row) and formation of a part of the dot row (that is, a part of the dot row. Drives the dot-forming element, but does not drive the dot-forming element for the other parts).

The medium transport mechanism control unit controls the medium transport mechanism to
The pitch feed amount data is transmitted in pitch units. The medium transport mechanism transports the medium in the sub-scanning direction at a predetermined pitch feed amount based on the pitch feed amount data.

The print head control unit, the carriage drive mechanism control unit and the medium transport mechanism control unit can be constituted by, for example, a dedicated processor (microprocessor, digital signal processor, etc.) or by independent circuits. Can also. Further, at least a part of these control units may be configured by a common circuit.

In the printer of the present invention, the dot forming element is composed of a plurality of dot forming element groups in which continuous dot forming elements form a single group. Although the dot forming elements of each dot forming element group are arranged at regular intervals on a straight line, it is not essential that the dot forming elements of all dot forming element groups be arranged on a straight line. For example, a dot forming element of another dot forming element group may be formed so as to be shifted by a predetermined distance in the main scanning direction with respect to a dot forming element of a certain dot forming element group. However, also in this case, all dot forming elements need to be arranged at regular intervals in the sub-scanning direction. For example, the lowermost dot forming element of a certain dot forming element group and the uppermost dot forming element of another dot forming element group adjacent to this dot forming element have the above-mentioned fixed interval in the sub-scanning direction. Must be arranged in such a way.

The medium transport mechanism control unit belongs to one dot row of a print image (in this specification, it means a row of dots in the sub-scanning direction) by only the dot forming elements of a single dot forming element group. So that all dots can be formed
The medium transport mechanism is driven.

Further, the print head control unit may be arranged so that each of the dot forming element row groups is the same as the number of dot forming element groups in which dot rows are discretely arranged in the sub-scanning direction. The print head is driven so as to form a dot row of the specific dot row group.

Therefore, even if an error occurs such that the dot interval becomes smaller than the original dot interval or becomes larger than the original dot interval in a certain portion of a certain dot row (even if it becomes the maximum), At least in the corresponding portion of the dot row formed by other nearby dot forming element groups, the error is not at least the same.

Further, in the printer according to the present invention, each of the dot forming element groups can form a dot row in a predetermined group order according to the movement of the carriage. For example, when the number of dot forming element groups (that is, the number of dot forming element groups) is 3, the first dot row is formed by the first dot forming element group, and the next dot row is formed by the second dot forming element group. Is formed, and the next dot row is further formed by the third dot forming element group, and this can be sequentially repeated. This can further reduce the occurrence of banding. Of course, the printer of the present invention is not limited to this.
, The first 2
A dot row is formed, the next two dot rows are formed by the second dot forming element group, and the next two dot rows are further formed by the third dot forming element group, and this can be sequentially repeated.

In the printer of the present invention, the control of the medium transport mechanism by the medium transport mechanism control unit can employ any control method as long as it is interlace control. For example, the medium transport mechanism control unit sends data corresponding to the pitch feed reference amount U represented by the following equation (1) to the medium transport mechanism with the pitch feed amount data being sent t times as one cycle. it can.

U = N × (D / t) (1) where t is an integer of 3 or more, and N is the number of dot forming elements having a “prime” relationship with t. D: dot forming element (D / t: distance equivalent to the dot interval in the sub-scanning direction of the image) In the present invention, the pitch feed error is different for the dots in the same dot row with the same dot forming element for different dot row groups. Banding based on errors is greatly reduced.

Further, in the printer of the present invention, a value obtained by adding data corresponding to the change amount △ _i expressed by the following equation (2) to U in the above equation (1) is used as pitch feed amount data. Can be.

Δ _i = −δ _i × (D / t) (2) where i: 1, 2,..., T δ _i : ≧ − (t−2), ≦ (t−2) ) become integers, in Sigma] [Delta] _i = 0 (2) wherein the [delta] _i is the information (values) corresponding to the pitch feed amount of change △ _i. The operation for setting と す る δ _i = 0 is as follows:
For example, it can be performed by an appropriate counter.

In the printer of the present invention, a change amount storage means for storing the information δ _i is provided in the medium transport mechanism control section. The change amount storage means stores δ ₁ , δ ₂ ,.
_As long as it can store _t , it may be a memory or a register. The change amount storage means constitutes a part of the medium transport mechanism control unit. For example, when the register of the image processor is used as the change amount storage means, the change amount storage means It may be provided separately from other parts of the transport mechanism control unit.

The information δ ₁ ,
δ ₂ ,..., δ _t are the pitch feed variation △
₁ , △ ₂ , ..., △ _t
Any code may be used. For example, t = 4
In the case of, the possible values of δ _i are -2, -1, 0, +
1, +2. When these values are stored in the registers, δ ₁ , δ ₂ , δ ₃ , δ ₄ are stored in the registers as 110,
It may be stored as a binary code notation indicating the magnitude of a numerical value, such as 101,000,001,010, or the like, or may be stored in a binary code notation not expressing the magnitude of a numerical value, for example, 000,001,010, For example, it may be stored as 011, 100 or the like.

[0030] The change amount storage unit (e.g. register), having a storage unit of fewer tau than t, [delta] ₁ to the tau-number storage unit, [delta] _2, · · ·, tau pieces of information of the [delta] _t Is stored ((t−τ) pieces of information are not stored). For example, when t = 4, the transmission of the pitch feed amount data four times is defined as one cycle, and △ ₁ , △ ₂ , △
₃ and △ ₄ are added to the pitch feed reference amount U. However, it is not necessary that all of △ ₁ , △ ₂ , △ ₃ , and と す る_{4 be} non-zero values. The two values are set to 0. For example, when △ ₁ is always 0, because the storage unit of the register for [delta] ₁ is not required, the register, [delta] _2, [delta] _3, sufficient if provided to the storage unit for the [delta] _4.

The print head is provided with a plurality of dot forming elements as described above. Interlaced printing is performed by the number N of dot forming elements having a “prime” relationship with t. However, the printer of the present invention is not limited to the number N described above, and a larger number of dot forming elements can be provided in the print head. For example, the number of dot-forming elements provided on the print head, by more than the number N, during printing, the pitch feed amount of change △ _1, △ _2, · · ·, the value of △ _t, the equation (2) The condition can be changed to satisfy the condition.

[0032] In the printer of the present invention, in advance, the change amount storage means, the amount of change △ _1, △ _2, · · ·, information [delta] ₁ corresponding to _{△ t, δ 2, ···,} δ t is stored You. The information δ ₁ , δ ₂ ,..., Δ _t can be written into the change amount storage means from outside the printer by visually observing and examining the image output by the test print. Alternatively, it can be written in the change amount storage means at the time of quality inspection before shipping. Further, software for a printer drive, drawing software, or the like may write the information δ ₁ , δ ₂ ,..., Δ _t into the change amount storage means.

The medium conveying mechanism control unit sending the t times the pitch feed amount data as one cycle, sequentially pitch feed variation △ _1, △ _2, · · ·, data about △ _t, pitch feed reference amount The pitch feed amount data PTD is created by adding to the data for U, and this is output to the medium transport mechanism.

The print head control unit can know which dot forming element should be driven by referring to the information δ ₁ , δ ₂ ,..., Δ _t stored in the change amount storage means. .

According to the printing method of the present invention, the dot pitch interval in the sub-scanning direction is D / t by a print head in which a plurality of dot forming elements are arranged at a constant interval in the sub-scanning direction. D: An image is printed so as to have an interval between the dot forming elements, and the plurality of dot forming elements are divided into a plurality of dot forming element groups in which a predetermined number of continuous dot forming elements form a single group. The medium is conveyed so that all the dots of one dot row of the image to be formed can be formed only by the dot forming elements of the single dot forming element group, and each of the dot forming element row groups is a dot. A dot row of a specific dot row group is formed from the same number of dot row groups as the number of dot forming element groups in which rows are discretely arranged in the sub-scanning direction. Here, each dot forming element of each dot forming element group is:
According to the movement of the carriage on which the print head is mounted, a dot row of an image to be printed can be formed in the order of a predetermined dot forming element group.

Both the printer of the present invention and the printing method of the present invention can solve the problem of eliminating banding.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 4 are explanatory views showing a first embodiment of the present invention. FIG. 1 is a diagram showing a printer of the present invention used in a first embodiment. An ink jet printer 101 includes a print head 11 and a carriage 1.
2. Carriage drive mechanism 13, medium transport mechanism 14, print head controller 15, carriage drive mechanism controller 1.
6, medium transport mechanism controller 17, image processor 18
have.

The carriage driving mechanism 13 includes a timing belt 131, a pulley 132, a motor (not shown), and the like. The pulley 132 is rotatably attached to the carriage 12, and the timing belt 131 reciprocates the carriage 12 in the main scanning direction (± x direction) via the pulley 132 by receiving the driving force from the motor (not shown). Can be moved.

The print head 11 is mounted on a carriage 12. As shown in FIG. 2, the print head 11 has dot forming elements (ie, nozzles) of 180 dpi in the sub-scanning direction (the y direction in FIG. 1). Nozzles NZ _{A01 to} NZ _A15 constituting the first nozzle group at a density of
And 15 nozzles NZ _B01 -N constituting the second nozzle group
Z _B15 are arranged in a row in a total of 30 pieces. In this embodiment, the case where 30 nozzles are formed serially in the print head 11 is shown. However, in the case of a color ink jet printer, for example, the same 30 nozzle rows as described above are formed in parallel (that is, in an array form). Formed). When the nozzles are formed in parallel, it goes without saying that each nozzle row operates so as to exhibit the functions and effects of the present invention.

The carriage drive mechanism controller 16 controls the carriage drive mechanism 13 by sending a reciprocating timing signal TS and the like to the carriage drive mechanism 13. The print head controller 15, in accordance with the reciprocating movement in the main scanning direction of the carriage 12, the print head 11, the nozzle NZ _A01 of the first nozzle group NZG _A to N
Sends a drive signal PHD _B for driving the drive signal PHD _A, the nozzle NZ _B01 ~NZ _B15 of the second nozzle group NZG _B for driving the Z _A15, to drive the print head 11.

The medium transport mechanism 14 receives the pitch feed amount data PTD from the medium transport mechanism control unit 17 and transports the medium 200 in the sub-scanning direction at a pitch feed amount U corresponding to the pitch feed amount data PTD. Can be.

In FIG. 1, the medium carrying mechanism 14 includes a medium carrying roller 141, a motor (in this embodiment, a stepping motor 142), a medium carrying auxiliary roller 143,
And a gear group 144. The driving force of the stepping motor 142 is transmitted to the medium transport roller 141 via the gear group 144, and is transmitted to the medium transport roller 141.
Transports the medium 200 in the sub-scanning direction (y-direction) so as to be sandwiched between the medium 200 and the medium transport auxiliary roller 143.

[0043] Figure 3 is a diagram showing the dripping operation of the ink droplets by the first nozzle group NZG _A. In the continuous pitch feed, the nozzles NZ _{A01 to} NZ of the first nozzle group NZG _A
A15 shows a state in which ink droplets are deposited on the medium 200 at intervals of one dot (that is, in the first dot row group). The pitch feed amount data PTD described above is
This is data indicating the magnitude of the pitch feed amount U, and the pitch feed amount U is N = 15 and D = 1 according to the above equation (1).
/ 180, t = 4 (that is, U = 1/48 (inch)).

When the medium 200 is conveyed by the pitch feed amount U, the nozzle NZ is used in the first pitch feed.
Ink drops from nozzles _A15 and NZ _A14 , ink drops from nozzle NZ _{A11 in the} second pitch feed, ink drops from nozzle NZ _{A07 in the} third pitch feed, and nozzle NZ _{A03 in the} fourth pitch feed Are applied to the medium 200 respectively. FIG. 3 shows a state in which the ink droplets are biased in the transport direction of the medium 200 (the lower side in FIG. 3). In FIG. 3, the dot (ink droplet) that has landed is indicated by the nozzle code that formed the dot.

[0045] Figure 4, the second nozzle group NZG _B, medium 2
At 00, a row not formed by the first nozzle group (second
3 shows a state in which ink droplets are applied to the dot row group). In Figure 4, a second nozzle group NZG _B, for easy understanding of the relationship between the first nozzle group NZG _A, shown in FIG. 3, the nozzle _{NZ A15, NZ A14, NZ A11} , NZ A07, NZ
The ink droplets (dots) from _A03 are also shown.

In FIG. 4, the pitch feed amount U in one pitch feed is 1/48 (inch) as in FIG.
_Therefore , the ideal positions of the nozzles NZ _B15 and NZ _B14 are the same as the ideal positions of the nozzles NZ _A15 and NZ _A14 in the pitch feed four times before, and are actually located at positions including errors. Ink droplets are deposited. Hereinafter, even in FIG. 4, as in the case of FIG. 3, the ink droplets from the second NZ _B11 is, the ink droplets from the nozzle NZ _B07 in the third pitch feed, also the nozzles NZ in fourth pitch feed
The ink droplets from _B03 are respectively deposited on the medium 200. In FIG. 4, the ink droplets travel in the transport direction of the medium 200 (FIG. 3).
(In the upper part). In FIG. 4 as well, the deposited dot (ink droplet) is indicated by the nozzle code that forms the dot.

As is apparent from FIG. 4, in this embodiment,
The dot rows of the first dot row group and the dot rows of the second dot row group are arranged alternately. In other words, the dots in the same dot row eject ink droplets with a plurality of (two in this case) dot forming elements having different errors, so that banding is greatly reduced.

[0048] In the first embodiment described above, for example, consider the first nozzle group NZG _A, over the fourth pitch feed from the first, there is a problem that each time the error of pitch feed is accumulated. FIG. 5 shows a case where the original pitch feed amount L is reduced by δ _L at each pitch feed, and FIG. 6 shows a case where the pitch feed is performed at each pitch feed.
This shows a case where the original pitch feed amount L is increased by δ _L.

In FIG. 5, N in the first pitch feed
Drop positions of ink droplets by Z _A14 and NZ _A15 (P ₁ , P ₅ )
The error of the droplet position (P ₄ ) of the ink droplet due to NZ _A03 in the fourth pitch feed is the error of the droplet position (P ₂ ) of the ink droplet by NZ _A11 in the second pitch feed, and N in the first pitch feed
The error of the ink drop landing position (P ₃ ) due to Z _A07 is accumulated. As a result, dripping position P ₄ would close distance total 3Deruta _L against dripping position P _5.

In FIG. 6, in the first pitch feed, the NZ _A14 and NZ _{A15 correspond} to the positions (P ₁ , P ₅ ) where the ink droplets are deposited by the NZ _A14 and NZ _A15 in the fourth pitch feed.
The error of the drop position (P ₄ ) of the ink droplet due to Z _A03 includes NZ _A11 in the second pitch feed as in the case of FIG.
Error of dripping position of ink droplets by NZ _A07 in error, and the third pitch feeding of dripping position of the ink droplets (P ₂₎ by (P ₃₎ is accumulated. As a result, dripping position P ₄ would be separated by a distance of total 3Deruta _L against dripping position P _5.

For this reason, in the printer or the printing method of the first embodiment, although banding is largely eliminated, there are cases where it is not always sufficient.

FIG. 7 is a diagram showing a printer used in the second embodiment of the present invention, which can solve such a problem. In the printer 102 of the present embodiment, FIG.
And a register (change amount storage means) 19, instead of the medium transport mechanism controller 17 shown in FIG.
2. A medium transport mechanism controller 19 having a change amount generator 193, an adder 194, and a counter 195 is used.

In this embodiment, the medium transport mechanism controller 19
Indicates that the media feed mechanism 14 outputs the pitch feed amount data PT four times.
With the transmission of D as one cycle, pitch feed amount data PTD obtained by adding data corresponding to the pitch feed change amount to data corresponding to the pitch feed reference amount U is sent. Registers 192 store information δ ₁ , δ ₂ ,... Corresponding to the pitch feed change amounts 対 応₁ , △ ₂ , △ ₃ , △ ₄ , respectively.
δ ₃ and δ ₄ are stored.

The change amount generating section 193 refers to the register 192 and generates data D _Δ for the pitch feed change amounts △ ₁ , △ ₂ , △ ₃ , △ ₄ . On the other hand, the pitch feed reference amount generation unit 191 generates data D about the pitch feed reference amount U.
Generate _U. And data D _U for the pitch feed reference quantity U, pitch feed variation _{△ 1, △ 2, △ 3} , data D _△ and are added by the adder 194 for △ _4. The medium transport mechanism control unit 19 determines the addition result (D _U + D _Δ )
Is sent to the medium transport mechanism 14 as the pitch feed amount U. Here, the counter 195 indicates that Σδ _i = δ ₁ + δ ₂ + δ ₃
+ Δ ₄ is counted, and the medium transport mechanism control unit 19 selects δ ₁ , δ ₂ , δ ₃ , and δ ₄ so that the count value becomes zero.

The medium transport mechanism control section 19 may calculate the pitch feed amount data PTD for each pitch feed, and may send this to the medium transport mechanism 14 one pitch at a time. Needless to say, the pitch feed amount data PTD can be stored in a stack provided in the medium transport mechanism control unit 19, the medium transport mechanism 14, and the like before the pitch feed.

In this embodiment, the print head controller 15
And the carriage drive mechanism controller 16 need to know the values δ ₁ , δ ₂ , δ ₃ , δ ₄ of the register 192. For this reason, the image processor 18 obtains these values and sends them to the print head control unit 15 and the carriage drive mechanism control unit 16. Of course, the present invention is not limited to this. For example, the print head control unit 15 and the carriage drive mechanism control unit 16 may use these registers 192 without passing through the image processor 18.
Control corresponding to the values δ ₁ , δ ₂ , δ ₃ , δ ₄ of
Control according to these values can also be performed.

In this embodiment, as in the first embodiment, the print data PD loaded on the printer 102 is stored in a buffer memory (not shown). This print data P
D is called by the print head control unit 15.
Then, the print head control unit 15 controls the first nozzle group N
A drive signal PHD _B corresponding to the nozzle NZ _B01 ~NZ _B15 constituting the driving signal PHD _A and the second nozzle group NZG _B corresponding to the nozzle NZ _A01 ~NZ _A15 constituting the ZG _A,
It is configured to output to the print head 11 in accordance with the operation of the carriage drive mechanism 13.

Hereinafter, the operation of the printer 102 will be described.

In this embodiment, the pitch feed reference amount, U = N × (D / t), the pitch feed change amount, Δ _i = −δ _i × (D / t), where δ _i : ≧ − (t −2), an integer that satisfies ≦ (t−2), and a value to which Σδ _i = 0 is added is the pitch feed amount U (see the above equations (1) and (2)). Specifically, U = 1/48 (inch). Since t = 4, δ _i is −
2, −1, 0, +1, +2, and considering the condition of Σδ _i = 0, δ ₁ = 0, δ ₂ = + 2, δ ₃ = −1, δ ₄ =
-1. Therefore, △ ₁ = 0 (inch), △ ₂
= -1 / 320 (inch), △ ₃ = △ ₄ = + 1/720
(Inches).

[0060] Figure 8 is a diagram showing the dripping operation of the ink droplets by the first nozzle group NZG _A, in four pitch feed the consecutive nozzles NZ _A01 ~ of the first nozzle group NZG _A
NZ _A15 shows a state in which ink droplets are deposited on the medium 200 at intervals of one dot. In the first pitch feed, ink droplets from the nozzles NZ _A15 and NZ _A14 are deposited on the medium 200.

In the second pitch feed, the medium transport mechanism control section 19 sends the pitch transport data PTD corresponding to (U + △ ₂ ) to the medium transport mechanism 14. Here, the pitch feed amount is U + △ ₂ (ie, 1
/ 48-1 / 320 (inch)), the stepping motor 142 is driven, and the print head control unit 15 sends a predetermined drive signal to each nozzle of the print head 11, so that the nozzle NZ _A11 An ink droplet is deposited on the medium 200.

In the third pitch feed, the medium transport mechanism controller 19 sends the pitch transport amount data PTD corresponding to (U + △ ₃ ) to the medium transport mechanism 14. Here, the pitch feed amount is U + △ ₃ (that is, 1/48 +
1/720 (inch)), the stepping motor 142 is driven, and the print head controller 15
Since a predetermined drive signal is sent to each nozzle of the print head 11, ink droplets are ejected from the nozzle NZ _A07 to the medium 200.
Is deposited.

In the fourth pitch feed, the medium transport mechanism control section 19 sends the pitch transport amount data PTD corresponding to (U + △ ₄ ) to the medium transport mechanism 14. Here, the pitch feed amount is U + △ ₄ (that is, 1/48 +
1/720 (inch)), the motor DM is driven, and the print head controller 15 sends a predetermined drive signal to each nozzle of the print head 11, so that the ink droplets from the nozzle NZ _A03 200 drops.
FIG. 8 shows a case where the actual pitch feed amount is smaller than the original pitch feed amount L by δ _{L at} each pitch feed, as shown in FIG. 5 (prior art). In the case of Figure 5, the error between adjacent dots (between dripping position) has been a maximum 3Deruta _L, a 2.delta. _L up to 8.

[0064] dripping operation of the ink droplet by the second nozzle group NZG _B is also performed in the same manner as FIG. FIG. 9 shows the nozzle NZ
_The positions of the ink droplets from _B15 and NZ _B14 are represented by P ₁ ′ and P ₅ ′.
Indicated by Also, the positions of the ink droplets from the nozzles NZ _B11 , NZ _B07 , and NZ _B03 are indicated by P ₂ ′, P ₃ ′, and P ₄ ′. 9, a second nozzle group NZG _B, for easy understanding of the relationship between the first nozzle group ZG _A, shown in FIG. 7, the nozzle _{NZ A15, NZ A14, NZ A11} , NZ A07, NZ
The ink droplets (dots) from _A03 are also shown. In FIG. 9, the actual pitch feed amount is equal to the original pitch feed amount L.
In each case, the pitch is increased by δ _L ′ in each pitch feed. FIG. 8 shows a case where the error is large, but in FIG. 9, the error is slightly small. As is clear from comparing FIG. 9 with FIGS. 5 and 6 (prior art),
In this embodiment, a plurality of (two in this case) dot forming elements form dots of the same dot row with different pitch feed errors, and also reduce the pitch feed error in the sub-scanning direction. Therefore, banding is eliminated.

[0065]

Since the same dot row is formed by a plurality of dot forming elements, the occurrence of banding can be reduced. Further, in a case where printing is performed on each dot row in a different order from the arrangement order of the dot rows in each row group in which continuous t rows are one group among the dot rows in the main scanning direction, the pitch The error in the feed amount can be eliminated, and the occurrence of banding can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a printer used in a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a print head used in the present invention, in which two sets of nozzle groups each including 15 nozzles are formed.

FIG. 3 is a diagram for explaining the operation of the first embodiment;
One of the 15 nozzle groups shown in FIG. 2 (first nozzle group)
FIG. 4 is an explanatory diagram of an ink droplet dropping operation according to FIG.

FIG. 4 is a diagram for explaining the operation of the first embodiment;
The other of the 15 nozzle groups shown in FIG. 2 (second nozzle group)
FIG. 4 is an explanatory diagram of the operation of depositing ink droplets according to FIG.

FIG. 5 shows a conventional interless printer, in which the original pitch feed amount L is δ at each time of pitch feed.
It is a figure for explaining the inconvenience when it becomes small only by _L.

FIG. 6 shows a conventional interless printer, in which the original pitch feed amount L is δ at each time of pitch feed.
It is a figure for explaining the inconvenience when it becomes large only by _L.

FIG. 7 is an explanatory diagram illustrating a printer used in a second embodiment of the present invention.

FIG. 8 is a diagram for explaining the operation of the second embodiment;
One of the 15 nozzle groups shown in FIG. 2 (first nozzle group)
FIG. 4 is an explanatory diagram of an ink droplet dropping operation according to FIG.

FIG. 9 is a diagram for explaining the operation of the second embodiment;
The other of the 15 nozzle groups shown in FIG. 2 (second nozzle group)
FIG. 4 is an explanatory diagram of an ink droplet dropping operation according to FIG.

FIG. 10 is an explanatory view schematically illustrating a conventional inkjet printer that performs printing in an interlaced mode.

11A and 11B are diagrams illustrating the principle of printing by a conventional interlace method, in which FIG. 11A shows the positions of ink droplets ejected from each nozzle during a medium conveyance stop period, and FIG. FIG. 4 is a diagram illustrating the principle drop position of ink from each nozzle during a transport stop period after one pitch feed of a medium.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Printer 11 Print head 12 Carriage 13 Carriage drive mechanism 131 Timing belt 132 Pulley 14 Medium transport mechanism 141 Medium transport roller 142 Stepping motor 143 Medium transport auxiliary roller 144 Gear group 15 Printer head control unit 16 Carriage drive mechanism control unit 18 Image processing processor 17, 19 Medium transport mechanism control section 191 Pitch feed reference amount generation section 192 Register 193 Change amount generation section 194 Adder 195 Counter NZG _A First nozzle group NZG _B Second nozzle group NZ _{A01 to} NZ _B15 Nozzles of first nozzle group Nozzles of the second nozzle group of NZ _{B01 to} NZ _B15

Continuation of the front page F term (reference) 2C056 EA06 EA08 EC69 EC78 FA02 FA10 2C057 DA09 DB01 DB03 DC08 DE10 2C062 AA24

Claims (5)

[Claims] A print head in which a plurality of dot forming elements are arranged at regular intervals in a sub-scanning direction; a carriage on which the print head is mounted; a carriage driving mechanism for reciprocating the carriage in a main scanning direction; A medium transport mechanism that transports a print medium at a predetermined pitch feed amount in the sub-scanning direction; a print head controller that drives the print head; a carriage drive mechanism controller that controls the carriage drive mechanism; And a medium transport mechanism control unit that controls the medium transport mechanism by sending pitch feed amount data in units of one pitch to the plurality of dot forming elements. A plurality of dot forming element groups, wherein the forming elements form a single group; Drives the medium transport mechanism so that all the dots belonging to one dot row of the print image can be formed by only the dot forming elements of a single dot forming element group; The printing is performed such that the forming element row group forms a dot row of a specific dot row group among the same number of dot row groups as the dot forming element group number in which the dot rows are discretely arranged in the sub-scanning direction. An interlaced printer characterized by driving a head. 2. The method according to claim 1, wherein each dot forming element group forms a dot row in a predetermined group order in accordance with movement of the carriage. The interlaced printer according to claim 1. 3. An image is printed such that a dot interval in the sub-scanning direction is D / t, where t: an integer of 3 or more, and D: an interval between dot forming elements.
5. The interlaced printer according to claim 1, wherein the medium transport mechanism control unit sets the transmission of the pitch feed amount data t times to the medium transport mechanism as one cycle, and calculates the following formula (1).
And the medium corresponding to the pitch feed reference amount U represented by the following formula (2) is added to the data corresponding to the change amount △ _i represented by the following equation (2). the transport mechanism control unit, interlaced printer, wherein a change amount storage means for storing information [delta] _i corresponding to the variation △ _i is provided. U = N × (D / t) (1) where N: the number of dot-forming elements having a “prime” relationship with t D: interval of dot-forming elements Δ _i = −δ _i × (D / t) (2) where i: 1, 2,..., T δ _i : an integer ≧ − (t−2), ≦ (t−2), Σδ _i = 0 4. A print head in which a plurality of dot forming elements are arranged at regular intervals in the sub-scanning direction, the dot pitch interval in the sub-scanning direction is D / t, where t: an integer of 3 or more. A method of printing an image such that a plurality of dot forming elements are divided into a plurality of dot forming element groups in which a predetermined number of continuous dot forming elements form a single group, wherein a single dot formation is performed. Only the dot forming elements of the element group
A print medium is conveyed so that all dots of one dot row of a print image can be formed, and each of the dot forming element row groups is a dot forming element in which dot rows are discretely arranged in the sub-scanning direction. An interlaced printing method, wherein a dot row of a specific dot row group is formed from among the same number of dot row groups. 5. A method according to claim 1, wherein each of the dot forming elements forms a dot row of a print image in a predetermined dot forming element group in accordance with the movement of a carriage on which a print head is mounted. 5. The interlaced printing method according to claim 4, wherein: