JPH09201955A - Printing equipment - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a printing apparatus that can obtain a high-quality image printing result even if printing is performed at high speed. A recording paper 41 is wound around a rotary drum 40 at an angle Θ, and an ink head 45 is tilted by an angle Θ with respect to a sub-scanning direction 53. It is characterized in that the relationship of advancing by the distance of the band width h of the ink head 45 is maintained when rotated. At this time, the angle Θ is a value uniquely determined by the equation tan Θ = h / L depending on the circumferential length L when the rotary drum 40 is expanded and the band width h of the ink head 45.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus for recording a recording material such as ink on a recording medium or an intermediate recording medium at high speed.

[0002]

2. Description of the Related Art In the case of an ink jet printing apparatus for printing a recording material such as ink on a recording medium such as paper, conventionally, a carriage equipped with an ink head is moved in a direction perpendicular to the movement of the paper, and the ink is moved in accordance with this. Then, one line is printed by ejecting, and when the printing is completed, the paper is moved in the sub-scanning direction, and the next main scanning is performed.

For example, one line is printed by ejecting the ink head while moving the carriage from the left end to the right end of the paper, and when the carriage has finished moving to the right end, the paper is moved by the height of the ink head. Then, when the movement of the paper is completed, by moving the carriage from right to left this time, the recording of the next main scanning line is completed. The printing of one page is completed by repeating this to the rear end of the paper.

FIG. 1 shows this conventional printing apparatus. Although it is known that an inkjet printer is equipped with four color ink cartridges, a case where a black ink cartridge is installed will be described here for the sake of simplicity.

The recording paper 3 fed from the paper feed cassette tray 1 by the paper feed roller 2 is conveyed by the platen motor 5 so as to be wound around the platen roller 4.
When the printing of the recording paper 3 is completed up to the position of the transport mechanism (hereinafter abbreviated as the carriage) 7 that mounts the ink head (see FIG. 2), the platen 4 stops. When the carriage drive motor 6 slides the carriage 7 fixed to the conveyance belt 8 and moves to the edge of the paper, the platen motor 5 causes the recording paper 3 to go perpendicular to the carriage scanning direction (called the main scanning direction). It is moved in the scanning direction.

FIG. 2 shows the ink head held on the carriage of FIG. Normally, a plurality of ejection ports 29 of the ink head are arranged in the sub-scanning direction. For example, as shown in (a), by having two rows of ink ejection ports in the main scanning direction 20, the gaps between the ink ejection ports are complemented. Further, as shown in (b), the ink ejection port group is in one row, and there is also a configuration in which the gap of the ink ejection ports in one row is compensated by repeating the paper feeding three times in the sub-scanning direction. . In either example, one sheet feeding in the sub-scanning direction may be performed by the distance indicated by h in the drawing (which will be referred to as the ink head band height). The printing of one page is completed by repeating this to the end stage of the paper.

FIG. 3 shows an example of the locus of the ink head on the recording paper 3 in the conventional example of FIG. Reference numeral 32 denotes a locus in the main scanning direction due to head scanning, and 33 denotes a locus in the sub scanning direction due to paper conveyance. Here, printing is performed both when scanning the head from left to right and when scanning from right to left. One sub-scanning direction is performed during the continuous main scanning printing. The amount of paper conveyed to is a value determined by the band height h of the ink head described above.

Further, as another printing method, an intermediate recording drum is provided, and this intermediate recording drum is used instead of paper as a recording medium onto which recording material such as ink is sprayed, so that the recording material is once recorded on the intermediate recording medium. A method is also known in which it is then transferred to a recording medium.

In this case, the recording in the main scanning direction is the same as the above-mentioned method, but the recording in the sub scanning direction is different in that a rotary drum as an intermediate recording medium is interposed.

[0010]

By the way, in the case of the conventional printing method, since the recording is performed on the recording medium by the reciprocating movement of the carriage and the conveyance of the paper as described above, the printing completed by one main scanning is performed. Image (hereinafter called print band)
It is known that the connection between the print band and the next print band easily shifts up, down, left, and right, and as a result, vertical lines do not connect straight, or the print bands overlap vertically or are separated. .

This is because the connection of the print bands shifts to the left and right when the carriage is printed from right to left and when it is moved from left to right due to the precision of the gears. Therefore, for example, a method of recording on a recording medium is usually performed only when the carriage is moved from left to right, but in that case, there is a problem that the printing speed becomes considerably slow.

Further, in order to increase the speed by the conventional printing method, it is necessary to increase the carriage conveying speed. In that case, the carriage needs to start accelerating from one end to maintain a constant speed, and finally decelerate and stop, but in high-speed printing, it takes time to reach a constant speed.
The run-up distance to the recording medium must be provided at the end. However, in that case, the printing apparatus becomes large.

In the conventional printing method, generally, the position of the ink head is detected by a step motor or a rotary encoder and the timing for ejecting the recording material is controlled to be synchronized with this. Since the printing accuracy is required for this method as the speed is increased, there is also a problem that the mechanism becomes expensive.

Further, in the conventional printing method, not only the mechanism for moving the carriage but also the mechanism for transporting the paper is required to have high accuracy, so that the overall control is complicated and complicated. There is also.

Further, among the conventional printing methods, particularly in the ink jet recording method, a relatively large unprintable area is generated at the lower end of the recording medium, which is smaller than the printable range of the laser printer. There is also a problem that the layout of the print information once created has to be changed when printing with a laser printer, for example.

[0016]

The present invention has been conceived in order to solve such a problem, and has the following configuration.

That is, a cylindrical drum rotating at a constant speed,
A recording head for adhering a recording material, a recording head holding means for holding the recording head at an angle Θ with respect to the rotation axis of the cylindrical drum, and a recording head for rotating when the cylindrical drum rotating at a constant speed makes one rotation. Constant velocity moving means for moving the recording head holding means in parallel to the rotation axis of the cylindrical drum by the bandwidth of the recording head, the circumferential length of the cylindrical drum is L, and the bandwidth of the recording head is h. Angle Θ
Is a value that is uniquely determined by tan Θ = h / L.

Further, in the printing apparatus of the present invention, the moving means has a constant speed at least while the recording material is attached to the recording medium, and the band width of the recording head is just when the cylindrical drum makes one rotation. The recording head is moved in parallel with the rotation axis of the cylindrical drum.

Further, the printing apparatus of the present invention further comprises recording medium holding means for winding and holding the recording medium on the cylindrical drum at an angle Θ with respect to the rotation axis of the cylindrical drum, so that the recording medium is wound on the cylindrical drum. Printing is performed by attaching a recording material to the obtained recording medium by a recording head.

Further, the printing apparatus of the present invention includes a rotating cylindrical drum, a recording head for ejecting recording material in the direction of the cylindrical drum, and a recording head for holding the recording head at an angle Θ with respect to the rotation axis of the cylindrical drum. Holding means and moving means for moving the recording head holding means in parallel with the rotation axis of the cylindrical drum by the band width of the recording head when the rotating cylindrical drum makes one rotation. Is Vd and the moving speed of the recording head holding means in the direction parallel to the rotation axis of the cylindrical drum is Vh, the relationship of Vd = kVh (k is a constant) is always satisfied and the circle of the cylindrical drum is When the circumference is L and the band width of the recording head is h, the angle Θ is uniquely determined by tan Θ = h / L.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 4 shows an ink jet type printing apparatus showing an embodiment of the present invention.

The recording paper 41 fed from the paper feed cassette 47 by the paper feed roller 48 is electrostatically attracted to the motor 50.
Is wound around the rotating drum 40. At this time, the recording paper 41 is wound around the rotary drum so as to form an angle Θ with the rotation axis of the rotary drum. Here, the angle Θ is a value that is uniquely determined by tan Θ = h / L, where L is the circumferential length of the rotary drum 40 and h is the band width of the ink head 45. The paper is fed at an angle Θ with respect to the rotation axis of the rotating drum regardless of the size of the printing paper 41.

Here, the paper feeding cassette 47 is mounted at an angle Θ with respect to the regular cassette mounting position shown by the dotted line from the beginning, but the paper feeding cassette 47 is mounted at the regular position. At the time of paper feeding, the paper may be fed at an angle Θ with respect to the rotation axis of the rotary drum.

FIG. 8 is a view showing the ink head 45 mounted on the carriage of this embodiment. In this example, the ink ejection ports are arranged in one row. Ink head 45
Is a tangent 55 on the drum surface parallel to the axis of rotation of the rotating drum
On the other hand, it is fixed to the head transport belt 44 at an angle Θ as shown in FIG.

The ink head 45 is held by a carrying means (not shown) called a carriage, and is driven by a head carrying motor 52 and a head carrying belt 44 at a constant speed as indicated by an arrow 53.
In the sub-scanning direction. This speed is
Is set so as to move in the sub-scanning direction by one shift amount h, that is, by the band width of the ink head. That is, the angle Θ can be said to be an angle formed by the trajectory drawn when the ink head 45 makes one rotation around the rotary drum 40 with respect to the main scanning direction 42.

Now, when the winding of the recording paper 41 is completed, the rotary drum 40 starts to rotate at a constant speed in the main scanning direction of the arrow 42.

The recording start timing detector 46 detects the recording start marker 51 and generates a printing start pulse when the rotation of the drum becomes constant. The print start pulse gives the recording start timing of the recording paper 41, and the ink head 45 starts ejecting ink in synchronization with this pulse.

FIG. 9 is a view of the rotary drum 40 unfolded and seen from the side where the ink head is scanned. As can be seen from this figure, the printing paper to be placed on the rotary drum 40 may be any size as long as it is the size of the rotary drum 40 or less. Conversely, by increasing the diameter of the rotary drum 40, it is possible to deal with various sizes of printing paper. For any size of printing paper, the paper length direction must always adsorb at an angle Θ with respect to the main scanning direction 42. Also, the main scanning direction 42
The printing is performed so that the point 54 on the scanning start side in the sub-scanning direction 53 on the rotation progressing side of C is always the distance C (C is a constant) with respect to the parallel line of the recording start marker 51 with the sub-scanning direction 53. It is also necessary to adjust the adsorption of paper. As a result, the suction position of the printing paper is always uniquely determined.

When the rotary drum 40 makes one rotation after the print start pulse is generated, the printing of one band is completed. Here, for example, in the case of A4 size paper, the band is an area shown by hatching in FIG. The band width indicates the band width h of the ink head 45. Generally, the printing of the band N is started after the print start pulse is generated, but in this case, the printing is started earlier than the printing of the band 1 by a time corresponding to the distance of Nhtan Θ. Printing of all the bands is repeated, and when the entire recording paper is printed, printing of one page is completed.

FIG. 5 is a view of the rotary drum 40 shown in FIG. 4 as developed and viewed from the side where the ink head is scanned. The ink head 45 makes an angle Θ with a tangent 55 on the drum surface. By moving in the sub-scanning direction 53, the ink head 45 moves on the rotary drum 40 by passing through the band corresponding region 57 of the band 1 shown by the diagonal lines. The width is not limited to the band-corresponding region 57 of the band 1, but is the band width h of the ink head in all the band-corresponding regions 57. 1 of the rotating drum 40
At the moment when the movement of the ink head for the rotation is finished, the ink head is at the start position of the next band corresponding area 57,
Since the band corresponding region 57 is continuously processed, the speed is high and the positional deviation is unlikely to occur. Chart paper 4
1 is always adsorbed on the rotary drum 40 at an angle Θ with respect to the main scanning direction 42.

The ink head 45 is shown in FIG.
It is needless to say that the two-row interpolation type head shown in (a) is applicable in the same manner to the ink head shown in FIG. 2 (b). That is, it is sufficient to set the rotary drum 40 to move by the band width h of the ink head until the rotary drum 40 makes one rotation and reaches the start position of the next band corresponding region 57. However, in the case of the ink head of FIG. 2B, the ink ejection ports 29 are in one row, and a plurality of rotations are performed to fill a gap and form a print image in order from the edge of the printing paper 41 with a width h. Sometimes,
As compared with the case where the ink head of FIG. 2A is used, the printing time will be lengthened somewhat. However, this can be easily solved by increasing the number of the ink ejection ports 29 to the same level as the ink heads of FIG.

FIG. 6 shows a block diagram of the controller of this printing apparatus.

CP in synchronization with the clock signal generation circuit 66
The U60 executes the instruction read from the ROM 61 and controls the entire controller. When an emergency process (not shown) such as an interrupt is requested, the interrupt process is performed while maintaining the current state, and after this is completed, the execution is continued again. In addition to the instructions, the ROM 61 stores a table, initialization data, fonts, and the like. The print information sent from the host computer 62 is stored in the reception buffer existing in the RAM 64 through the interface circuit 63. The CPU 60 analyzes the contents of this reception buffer and converts it into intermediate print information suitable for printing by an engine (not shown).

The intermediate print information divides the image to be printed into bands as shown in FIG. 7, and stores the bands in the RAM 64 as a storage unit. The width of these bands is, of course, the band width h of the ink head described above. Then, for example, when the intermediate print information for one page is completed, the controller sends I / O to the engine.
The engine control device 69 is instructed to start printing via the control circuit 68. In that case, first, the intermediate print information of the band 1 and the band 2 is converted respectively on the band memory A and the band memory B on the RAM 64, and these are temporarily saved to D.
Wait for the transfer start of MA71. When the recording start signal is output from the timing signal generation circuit 72 when the recording start timing detector 46 detects the recording start marker 51, DM
A71 starts its operation, and the bit image of band 1 on the band memory A is sent to the ink head drive circuit 67 via the video interface of the engine by the DMA 71, and the ink droplets are ejected onto the recording paper.

When the transmission of the bit image on the band memory A is completed, the process for converting the intermediate print information of band 3 to the band memory A is started this time. At the same time, the bit image of band 2 on the band memory B is preceded by htan Θ on the rotary drum 40 from the print start position when the bit signal of band 1 was previously printed on the recording paper by the timing signal generating circuit 72. Printing starts at the timing. When the transmission of the bit image on the band memory B is completed, the process of converting the intermediate print information of band 4 onto the band memory B is started this time. At the same time, the printing of the bit image of band 3 on the band memory A starts at the timing as described above. Printing for one page is completed by continuing this to band n. In addition, 1
When expanding a bit image for a page, 1 in FIG.
It is arbitrary to process assuming that the upper left of the page is the upper left of the actually obtained print image, or the lower right is the upper left of the print image.

FIG. 11 is a control flow of the printing mechanism of the printing apparatus of this embodiment. First, the band counter N is cleared (120). When the recording medium 41 fed by the feed roller 48 is wound around the rotary drum 40 (1
21), the rotating drum 40 is rotated at a constant rotation speed by the motor 50 (123). In parallel with this, the ink head is moved to the home position by the transport motor 52 (124). On the other hand, the CPU calculates the print delay distance D (125). Initially, D is equal to the constant C. After the print start permission is given (126), when the recording start timing detector 46 detects the recording start marker 51, it waits for the rotary drum to rotate by the distance D (12).
7) The sub scanning of the ink head is started (128).
After that, sub-scanning of the ink head continues, and the rotary drum 40
When the recording start timing detector 46 detects the recording start marker 51 again after one rotation, printing is performed with a delay corresponding to the newly calculated print delay distance D (129). These delays are timing adjustments for starting printing from the lower end (upper end) of the paper for each band.

Next, it is checked whether or not there is an image to be printed in the print band (130). This can be determined by analyzing the intermediate print information. If any,
When the recording of the recording material on the recording medium is started (131) and the printing for one band is completed, the band counter is set to 1
Only increase (132). If printing of all bands on one page has not been completed, the process returns to 125 again to calculate the print delay distance D of the next band. For example, the second
In the case of a row band, D becomes C-htan Θ. h is the bandwidth. That is, the print start position of the band of the second row is started by htan Θ earlier than that of the first band. The above is repeated until the end of one page. N indicates the maximum value, 1
When the printing of all the bands of the page is completed, the printing of one page is finished (133). The recording medium wound around the rotary drum is separated (138) and discharged (139).

By the way, it is checked whether or not there is an image to be printed in the print band (130), and if an empty band is detected, the number M of consecutive empty bands is calculated (1
34), and move the ink head forward by M bands (13
5). At this time, the ink head does not necessarily need to be sent at a constant speed, and if sent faster, the printing time can be shortened accordingly. After that, when the process advances by M bands, the band counter N is incremented by M (136), and the process returns to 133 to prepare for the next band printing.

In this way, the rotary drum 40 is continuously rotated in one direction at a constant speed, and the ink head 45 is continuously moved in one direction at a constant speed. In addition, it is possible to perform printing without misalignment. Moreover, the ink head does not necessarily need to be sent at a constant speed, and may be variable depending on the presence or absence of band data. Furthermore, it is not necessary to start printing from the state where the rotation speed of the rotary drum 40 and the moving speed of the recording head 45 are both constant, and when the rotation speed of the rotary drum 40 is low at the start of rotation of the rotary drum 40, In addition, if the moving speed of the recording head 45 is decreased and the rotating speed of the rotary drum 40 is increased, the moving speed of the recording head 45 may be increased accordingly. In short, the rotational peripheral speed of the rotary drum 40 is Vd, the recording head 45
When the moving speed of V is Vh, it is sufficient if at least the relationship of Vd = kVh (k is a constant) is satisfied during recording. In that case, it is advantageous in design that the motor 50 used to rotate the rotary drum 40 and the transport motor 52 of the ink head 45 are the same.

The present invention is not limited to ink as a recording medium. That is, the structure may be such that the toner is sprayed or the wire is pressed against the rotating drum while sandwiching the ribbon as is known in the impact dot matrix printer. Further, the ink is not particularly limited to a single color.

Further, in this embodiment, the printing paper is wound around the rotary drum and the recording medium is jetted directly onto the printing paper. However, the recording medium is jetted onto the rotary drum and the printing medium attached on the drum is turned onto the recording paper. It is also possible to obtain a printed matter by transferring. FIG. 10 shows this example. That is, after the recording medium is completely attached to the rotating drum 40 by the main scanning of the rotating drum 40 and the sub-scanning of the recording head 45, the upper end of the printing paper 41 from the paper feed tray 101 is in the rotation axis direction of the rotating drum 40. The recording medium is fed at an angle Θ with respect to the recording medium and is transferred by the transfer means 103 onto the recording medium. Then, the print paper 41 to which the print image is transferred is discharged to the paper discharge tray 102. Here, the transfer means 103 is composed of a transfer roller and a heater.

Further, in FIG. 9, all the printing papers 41 are fed in the portrait direction (longitudinal direction).
Of course, it is also possible to feed in landscape (landscape direction).

Further, in FIG. 9, any size of printing paper
The sub-scanning direction 53 is on the traveling side of the main scanning direction 42.
The suction of the printing paper is adjusted so that the point 54 on the scanning start side of is always the distance C (C is a constant) with respect to the parallel line of the recording start marker 51 with the sub-scanning direction 53. There is also a method of adsorption as shown in FIG. In FIG. 12, the point 54 on the scanning start side in the sub-scanning direction 53 is movable according to the size of the printing paper on the side of the main scanning direction 42 in the direction of rotation, and instead, on the side of the direction of rotation in the main scanning direction 42. The point 56 on the scanning traveling direction side of the sub-scanning direction 53 is always placed on the parallel line of the recording start marker 51 to the sub-scanning direction 53. In this case, depending on the size of the paper, the constant C
Need to be switched, and its value is w with paper width as w
It can be calculated by tan Θ. Also in this method, the control flow is the same as that shown in FIG.

Although FIG. 7 shows an example having two band memories, it is naturally possible to have more band memories.

As described above, in the printing apparatus of the present invention, the recording paper 41 is wound around the rotary drum 40 at the angle Θ, the ink head 45 is inclined at the angle Θ with respect to the sub-scanning direction 53, and the ink head 45 is rotated. When 40 rotates once, the ink head 45 is moved at a speed of advancing by the distance of the band width h. At this time, the angle Θ is a value uniquely determined by the equation (tan Θ = h / L) depending on the circumferential length L when the rotary drum 40 is expanded and the band width h of the ink head 45.

[0046]

The rotational speed of the rotary drum and the moving speed of the head transport are constant, and the sub-scanning and main-scanning mechanisms can be easily and inexpensively realized by constantly rotating / moving in one direction. is there. That is, in the conventional printing method, it is necessary to repeat the scan in which the carriage starts accelerating from one end, reaches a constant speed, and finally decelerates and stops, so the position of the ink head is detected by a rotary encoder or step motor. Although it is necessary to synchronize the timing of ejecting the ink with this, the rotating drum and the carriage are not necessary in the present invention because they have a constant speed.

Further, there is a problem that the connection between a print image (hereinafter referred to as a print band) completed by one main scan and the next print image is vertically and horizontally shifted, and the width of the ink head is slightly deviated by the width unit. Problems such as vertical line discontinuity that occur in are solved.

Further, it is also possible to solve the problem that the print bands are vertically overlapped or separated from each other due to variations in the paper feeding accuracy in the main scanning direction.

Further, unlike the printing method of the conventional ink jet printing apparatus, it is not necessary to move the carriage for carrying the ink head from the left end to the right end and then return it to the left end, so that high speed printing is possible.

Further, in the printing method of the conventional ink jet printing apparatus, the unprintable area at the lower end of the printing paper is large, but in the present invention, the printing area on the recording paper can be made relatively large.

Further, since the same motor 50 used to rotate the rotary drum 40 and the transport motor 52 of the ink head 45 can be used, it can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a conventional inkjet printing apparatus.

FIG. 2 is a diagram showing an example of an array of ejection holes of an ink head.

FIG. 3 is a diagram showing a movement trajectory of an ink head with respect to a recording paper in a conventional printing apparatus.

FIG. 4 is a diagram showing an appearance of a printing apparatus according to an embodiment of the present invention.

FIG. 5 is a diagram for explaining the movement of the ink head on the plane of the rotating drum in the embodiment.

FIG. 6 is a block diagram showing the configuration of a printing apparatus according to the present invention.

FIG. 7 is a view showing a group of bands virtually divided to process one page in the example.

FIG. 8 is a diagram illustrating the inclination of the ink head in the embodiment.

FIG. 9 is a diagram showing printing paper adsorbed on the plane of a rotating drum in the embodiment.

FIG. 10 is a diagram showing an example in which the printing apparatus according to the present invention is applied to a transfer type printing mechanism.

FIG. 11 is a diagram showing an example of a control flow of the printing apparatus according to the present invention.

FIG. 12 is a diagram showing a printing paper attracted on a rotary drum plane in another embodiment.

[Explanation of symbols]

 40 Rotating Drum 44 Ink Conveying Belt 45 Ink Head 46 Recording Start Timing Detector 51 Printing Start Marker 72 Timing Signal Generation Circuit

Claims (5)

[Claims] 1. A cylindrical drum rotating at a constant speed, a recording head for adhering a recording material, recording head holding means for holding the recording head at an angle Θ with respect to a rotation axis of the cylindrical drum, and the constant head. And a constant speed moving means for moving the recording head holding means in parallel with the rotation axis of the recording drum by the band width of the recording head when the rotating cylindrical drum rotates once. When the circumference is L and the recording head bandwidth is h, the angle Θ is tan Θ = h
A printing device characterized in that the value is uniquely determined by / L. 2. The printing apparatus according to claim 1, wherein the moving unit is at a constant speed at least while the recording material is attached to the recording medium, and the band of the recording head is just when the cylindrical drum makes one rotation. A printing apparatus, wherein a recording head is moved in parallel with a rotation axis of the cylindrical drum by a width. 3. The printing apparatus according to claim 1, further comprising a recording medium holding unit that winds and holds the recording medium with respect to the cylindrical drum at an angle Θ with respect to a rotation axis of the cylindrical drum. A printing apparatus, which prints by applying a recording material to a wound recording medium by a recording head. 4. The printing apparatus according to claim 1, wherein the sheet feeding means for feeding the recording medium at an angle Θ with respect to the rotation axis of the cylindrical drum, and the recording material attached to the cylindrical drum are fed by the sheet feeding means. A printing apparatus, further comprising: a transfer unit that transfers the recording medium onto paper. 5. A rotating cylindrical drum, a recording head for ejecting a recording material in the direction of the cylindrical drum, recording head holding means for holding the recording head at an angle Θ with respect to the rotation axis of the cylindrical drum, and the rotating. Moving means for moving the recording head holding means in parallel with the rotation axis of the cylindrical drum by the band width of the recording head when the cylindrical drum makes one rotation, and the rotational peripheral speed of the cylindrical drum is Vd, When the moving speed of the recording head holding means in the direction parallel to the rotation axis of the cylindrical drum is Vh, Vd = kVh (k is a constant)
When the circumferential length of the cylindrical drum is L and the band width of the recording head is h, the angle Θ is tan Θ = h
A printing device characterized in that the value is uniquely determined by / L.