JPH10278367A - Printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable printing to many kinds of print media each having a print face of a predetermined radius of curvature, by detecting the radius of curvature of the print face of the print medium and print the medium while controlling a rotational angular velocity of the print medium by a medium-rotating means on the basis of the detected result. SOLUTION: When a belt-driving roller 30 rotates by a predetermined amount, a print medium 26 on a transfer belt 29 drops in between a pair of inclined faces 32a and 32b of a measurement block 32 and supported by the measurement block 32. At this time, a touch sensor 33 moves downward on a bisector of an angle defined by the pair of inclined faces 32a, 32b. At a position when the touch sensor 33 comes in touch with the medium 26, the touch sensor 33 transmits a heightwise position of itself to a control part. The control part obtains a distance to an upper end of the medium 26 from a preliminarily set intersection of the pair of inclined faces 32a, 32b, and calculates a radius of the print medium 26 from the distance. A rotational angular velocity of the medium 26 is controlled on the basis of the calculated result when printing is conducted.

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 printing on a printing medium having a printing surface with a predetermined radius of curvature, such as a cylindrical object.

[0002]

2. Description of the Related Art Quality assurance of design patterns such as pictures and patterns on the outer peripheral surface of cylindrical objects such as cans and tea caddies, or explanations and precautions of product names and usage methods, and display of producer names, etc. As a method of printing items, the above-mentioned notation is performed on paper or film by screen printing or offset printing, and the printed paper or film is wound around the outer peripheral surface of the cylindrical object and adhered,
Alternatively, the above-mentioned notation is generally printed on the outer peripheral surface of a cylindrical object by screen printing.

[0003]

In a conventional method in which a printed matter such as paper or film is attached to the outer peripheral surface of a cylindrical object, or is directly printed on the outer peripheral surface of the cylindrical object by screen printing, a conventional method is used. The contents change,
Each time the dimensions of the cylindrical object are changed, it is necessary to newly make a printing plate, and the date and time required for manufacturing the printing plate are required. For this reason, not only the notation cannot be quickly changed, but also the production cost of the printing plate increases.

[0004] Such a problem is remarkable especially in the case of a product manufactured in a small lot because it takes time to set a printing plate on a printing press. In addition, if the contents of the notation differ from one another, such as the serial number of the product, the date and time of manufacture, and the like every day, a special printing machine for that purpose must be additionally provided, which has the disadvantage of increasing the equipment cost.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printing method capable of directly printing on various types of printing media each having a printing surface with a predetermined radius of curvature, irrespective of screen printing or the like requiring a printing plate. It is to provide a device.

[0006]

According to a first aspect of the present invention, there is provided a medium holding means for holding a print medium having a print surface having a predetermined radius of curvature, and the medium holding means is provided with a curvature of the print surface of the print medium. Medium rotating means for driving and rotating about a center, a print head opposed to the print surface of the print medium and performing printing on the print surface, and print surface measuring means for detecting a radius of curvature of the print surface of the print medium And a control means for controlling a rotation angular velocity of the print medium by the medium rotation means based on a detection result by the print surface measurement means.

According to the present invention, the print surface measuring means detects the radius of curvature of the print surface of the print medium, and based on the detection result, the control means controls the rotational angular velocity of the print medium by the medium rotating means, while controlling the print head. As a result, printing is performed on the print surface of the print medium.

According to a second aspect of the present invention, there is provided a medium holding means for holding a print medium having a print surface with a predetermined radius of curvature, a medium rotating means for driving and rotating the medium holding means, and the print surface of the print medium. A print head that prints on the print surface, a print surface measurement unit that detects a radius of curvature of the print surface of the print medium, and the print medium that is obtained based on the detection result by the print surface measurement unit. And a medium positioning means for supplying the print medium to the medium holding means such that the center of curvature of the medium and the rotation center of the medium holding means coincide with each other.

According to the present invention, the radius of curvature of the print surface of the print medium is detected by the print surface measuring means, and the medium positioning means supplies the print medium to the medium gripping means based on the detection result, and the center of curvature of the print medium is detected. The print medium is gripped by the medium gripping means so that the rotation center of the print medium coincides with the rotation center of the medium gripping means. In this state, printing is performed on the print surface of the print medium by the print head.

According to a third aspect of the present invention, there is provided a medium holding means for holding a print medium having a print surface having a predetermined radius of curvature, and driving and rotating the medium hold means around a center of curvature of the print surface of the print medium. Medium rotating means, a print head opposed to the print surface of the print medium for printing on the print surface, print surface measurement means for detecting a radius of curvature of the print surface of the print medium, and print surface measurement A printing apparatus, further comprising: an image processing unit for making a width of image data along a circumferential direction of the print surface correspond to a circumferential length of the print surface based on a detection result by the means.

According to the present invention, the radius of curvature of the print surface of the print medium is detected by the print surface measuring means, and the image processing section prints the width of the image data along the circumferential direction of the print surface based on the detection result. The print head prints on the print surface of the print medium in a state corresponding to the circumference of the surface.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a printing apparatus according to a first embodiment of the present invention, the control means may control the peripheral speed of a print medium to a constant speed regardless of the radius of curvature of a print surface. preferable.

In the printing apparatus according to the first to third aspects of the present invention, the print head is driven based on a result of detection by the print position measuring means and a head position adjusting means for driving the print head in a direction facing the print surface of the print medium. Control means for controlling the operation of the head position adjusting means such that the distance between the print surface of the medium and the print head is a predetermined distance may be further provided.

The print surface measuring means has a V block having a pair of inclined surfaces which intersect each other, and a sensor for detecting a distance between a print surface of a print medium held by the V block. There may be.

Further, it is preferable that the print medium has a cylindrical or cylindrical shape.

On the other hand, the print head may have a discharge energy generating section for discharging ink from the discharge port. In this case, the discharge energy generation unit
It is preferable to have an electrothermal converter that generates thermal energy. Further, it is effective that the ejection ports are arranged along a direction parallel to the rotation center of the medium holding means.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a printing apparatus according to the present invention will be described in detail with reference to FIGS. 1 to 9, but the present invention is limited to an ink jet printer which performs printing on the outer peripheral surface of such a cylindrical body. Of course, the present invention can also be applied to a print medium having a constant radius of curvature other than a cylindrical body and a printing apparatus of another type.

As shown in FIGS. 1 and 2 showing the appearance of the main part of this embodiment, a print head 11 for discharging ink from a discharge port (not shown) is arranged so that the discharge port faces vertically downward. The holder 12 is supported so as to be exchangeable. The head holder 12 is slidably connected to a holder guide 13 attached to a frame (not shown), and is movable along the longitudinal direction of the holder guide 13 via a belt (not shown) by a drive motor (not shown). ing.

The work base 14 includes a pair of base guides 15a and 15b supported vertically by a frame (not shown).
Are slidably supported with respect to the base guides 15a, 15b by a drive motor (not shown).

On the work base 14, a detachable motor bracket 17 for supporting and fixing the detachable motor 16 is provided.
And a bearing bracket 19 that supports the bearing 18. The feed screw shaft 20 is connected to the attaching / detaching motor 16, and the feed screw shaft 20 can be rotated by rotating the attaching / detaching motor 16. The motor 16 is preferably rotatable in both forward and reverse directions, and the feed screw shaft 20 is also rotatable in both forward and reverse directions in synchronism with the forward and reverse rotation of the motor 16.

At the other end of the feed screw shaft 20, a slide block 21 including a lead pin (not shown) that engages with the feed screw shaft 20 is supported. 13
Is movable in a direction parallel to the longitudinal direction of the. A medium rotation motor bracket 22 is fixed on the slide block 21, and a medium rotation motor 23 is fixed to the medium rotation motor bracket 22.
A gripping disk 25a is connected to a rotating shaft of the medium rotating motor 23 via a coupler 24, and the gripping disk 25a can be rotated by driving the medium rotating motor 23.

On the other hand, the bearing 18 is provided with a gripping disk 25b.
Are rotatably supported, and the rotation axes of the two gripping disks 25a and 25b are set coaxially. In controlling the medium rotation motor 23, it is necessary to arbitrarily control the rotation angular speeds of the gripping disks 25a and 25b, and it is desirable that the rotation speed be constant at the time of rotation. Therefore, a stepping motor or a built-in rotary encoder is preferable. It is desirable to use an AC motor or a DC motor.

The cylindrical print medium 26 is gripped at both ends by a pair of gripping disks 25a and 25b. The center of curvature of the outer peripheral surface of the print medium 26, that is, the print medium 26 The center axis is set coaxially with the rotation axis of the pair of gripping disks 25a, 25b.

A method of coaxially positioning the center axis of the print medium 26 and the rotation axes of the pair of gripping disks 25a and 25b will be described later.

A transfer block swing shaft 28, which is rotatably supported by a frame (not shown), protrudes integrally with the medium transfer block 27 that holds the print medium 26.

As shown in FIGS. 3 and 4, which respectively show the concept of the transport system of the print medium 26 in this embodiment,
A medium transport belt 29 is stretched between a belt driving roller 30 and a driven roller (not shown). The belt drive roller 30 is driven by a belt drive motor (not shown)
Intermittently rotates clockwise, and the medium transport belt 29
Is also intermittently conveyed.

Print media 26 having different outer diameters are placed on the medium transport belt 29. On the medium transport belt 29, the rolling of each print medium 26 on the medium transport belt 29 is performed to some extent. Protrusion 29a for regulating
Is provided. On the downstream side of the medium transport belt 29, a measurement block swing shaft 31 whose both ends are rotatably supported by a frame (not shown) is provided in parallel with the transfer block swing shaft 28. A measurement block 32 is fixedly supported on the swing shaft 31. The measurement block 32 is provided with a pair of inclined surfaces 32a and 32b that form an angle of 90 degrees with each other. Usually, the bisector of the angle formed by the pair of inclined surfaces 32a and 32b is defined as a vertical upward direction. It is set to be.

Above the bisector of the angle formed by the pair of inclined surfaces 32a and 32b, a touch sensor 33 is provided. The touch sensor 33 is driven in a vertical direction by a driving mechanism (not shown). It is possible to move on the bisector of the angle between the surfaces 32a and 32b. The touch sensor 33 can always transmit position information on its own height to a control unit (not shown).

The medium delivery block 27 is located downstream of the measurement block 32. Like the measurement block 32, the medium delivery block 27 also has a pair of inclined surfaces 27a having an angle of 90 degrees with each other. , 27b, and is usually set so that the bisector of the angle formed by the pair of inclined surfaces 27a, 27b is vertically upward.
Further, the positional relationship between the print head 11 and the medium delivery block 27 is determined by a nozzle line (not shown) of the print head 11 on a bisector of an angle formed by a pair of inclined surfaces 27 a and 27 b of the medium delivery block 27. It is set so as to be located above (vertically upward).

Next, the operation until the printing on the print medium 26 is performed will be described with reference to FIGS.

In FIG. 3, when the belt driving roller 30 receives power from a belt driving motor (not shown) and rotates by a predetermined amount, the printing medium 2 placed on the transport belt 29 is rotated.
6 is a pair of inclined surfaces 32a, 3 of the measuring block 32.
2b, the pair of inclined surfaces 32a, 32
b. The touch sensor 33 moves downward on the bisector of the angle formed by the pair of inclined surfaces 32a and 32b, and at a position where the touch sensor 33 has reacted, that is, at a position where the touch sensor 33 has contacted the print medium 26a,
The touch sensor 33 transmits its own height position to a control unit (not shown). The control unit includes a pair of inclined surfaces 32a, 32
Since the height of the intersection of the pair of inclined planes 32a and 32b has been input in advance, the control unit determines from the intersection of the pair of inclined surfaces 32a and 32b that the print medium 26
Can be known. In particular,
Assuming that the radius of the print medium 26 is r, H = (1 + 2)
^1/2 )), the radius of the print medium 26 is calculated using this relationship.

Incidentally, In the present embodiment, the measurement block 32 and the touch sensor 33 are arranged side by side on a vertical line for ease of explanation, but what is important is that the touch sensor 33 is formed by the angle 2 formed by the pair of inclined surfaces 32a and 32b. The same operation can be performed even if the measurement block 32 and the touch sensor 33 are tilted and supported. Further, in the present embodiment, the angle formed by the pair of inclined surfaces 32a and 32b is set to 90 degrees for ease of explanation.
It goes without saying that the radius of 6 can be calculated. Further, in this embodiment, the position of the upper end of the print medium 26 is measured by bringing the touch sensor 33 into contact with the upper end of the print medium 26, but the non-contact type sensor is fixed above the print medium 26. Then, by measuring the distance to the print medium 26,
It is also possible to calculate the radius of the print medium 26.

After the measurement of the radius of the print medium 26 is completed, the measurement block 32 is rotated by a predetermined amount by a drive source (not shown), and is tilted from the solid line state to the two-dot chain line state in FIG. Of the print medium 26 supported by the medium transfer block 2 from the measurement block 32
7 is transferred between the pair of inclined surfaces 27a and 27b. Further, the measurement block 32 is restored to the position indicated by the solid line in FIG.
It is ready to measure the radius of the next print medium 26 by avoiding the touch sensor 33 vertically upward.

Similarly, the height of the intersection of the pair of inclined surfaces 27a and 27b of the medium transfer block 27 is also input in advance to the control unit, so that the control unit controls the pair of inclined surfaces 27a and 27b of the medium transfer block 27. , The position of the center axis of the print medium 26b supported can be calculated.

The work base 14 shown in FIG. 1 is moved vertically by a drive motor (not shown) so that the center axis of the print medium 26 and the rotation axis of the pair of gripping disks 25a and 25b are calculated based on the above-described calculation results. Stop at the matching position. The phase in the horizontal direction between the center axis of the print medium and the rotation axes of the pair of gripping disks 25a and 25b is set in advance on the same plane. That is, the pair of gripping disks 25a and 25b are set so as to be always located on the bisector of the angle formed by the pair of inclined surfaces 27a and 27b of the medium transfer block 27.

After the work base 14 has been stopped in this way, the feed screw shaft 20 is rotated by driving the attaching / detaching motor 16. The slide block 21 continues to advance toward the side end surface of the print medium 26 by a lead pin (not shown) engaged with the feed screw shaft 20, and the gripping disk 25 a supported by the slide block 21 is attached to the end surface of the print medium 26. It is pressed. By further rotating the attaching / detaching motor 16, the gripping disk 25a presses the print medium 26 toward the other gripping disk 25b, and the other end surface of the print medium 26 is received by the gripping disk 25b. That is, the center axis of the print medium 26 and the pair of gripping disks 25
The print medium 26 is gripped by the pair of gripping disks 25a and 25b so that the rotation axes of the a and 25b are coaxial. The rotation amount of the attaching / detaching motor 16 may be determined by measuring the length of the print medium 26 in advance, or a pressure sensor may be provided on the pair of gripping disks 25a and 25b, and the pair of gripping disks 25a and 25b may be provided. 25
The rotation may be performed until a certain pressure is generated between the print medium 26 and the print medium 26.

The print medium 26 has a pair of gripping disks 2
After being supported by 5a, 25b, the work base 14
Rises and stops when the discharge port surface of the print head 11 and the upper end of the print medium 26 reach a certain preferable distance.

It is widely known that maintaining the distance between the ejection opening surface of the print head 11 and the surface of the print medium 26 to a desirable value in an ink jet printer is necessary for obtaining good print quality. ing. In this embodiment, since the radius of the print medium 26 has already been measured, the height position of the discharge port surface of the print head 11 and the preferable discharge port surface and the print medium 2 are determined.
The stop position of the work base 14 described above can be easily calculated by inputting the distance to the work base 6 in advance.

The print medium 26 is the print head 1
After facing the first discharge port surface at a preferable distance, the medium rotation motor 23 is driven. Thus, the print medium 26 is similarly rotated. In this case, in order to prevent slippage between the print medium 26 and the gripping disk 25a, it is also effective to provide a member having a high coefficient of friction, for example, a rubber material, on the surface of the gripping disk 25a in contact with the print medium 26.

When the rotation speed of the print medium 26 becomes constant, the print head 11 starts discharging ink and prints at a predetermined position on the outer peripheral surface of the print medium 26. After the start of printing, the print medium 26 makes one rotation, and printing on the print medium 26 corresponding to the array length of the ejection openings of the print head 11 is completed. afterwards,
Head holder 12 supporting print head 11
Is moved along a holder guide 13 by a drive motor (not shown) via a belt (not shown) by a distance equal to the arrangement length of the ejection ports of the print head 11, and during that, the print medium 26 continues to rotate at a constant speed. As described above, since the medium rotation motor 23 is a type of motor whose rotation angle can be controlled, the control unit (not shown) stores the start position of the print already performed on the print medium 26. Thus, the second row can be printed with the same print start point as shown in FIG.

The printing performed on the print medium 26 and the rotational speed of the print medium 26 during printing will be further described with reference to FIGS.

FIGS. 6 and 7 show a printing state when the print medium 26 is rotated at a constant angular velocity regardless of the outer diameter. FIG. 6 shows the print medium 2
6 shows the case where the outer diameter of the print medium 26 is relatively small, and FIG. 7 shows the case where the outer diameter of the print medium 26 is relatively small.

As shown in FIG. 6, when the print medium 26 having a large diameter is rotated at the same angular velocity, the moving speed on the outer peripheral surface of the print medium 26 is increased. If the ink ejection frequency from the outlet is constant, the position of the print surface of the print medium 26 moves greatly between one ejection and the next ejection. That is, in the print made on the peripheral surface of the print medium 26, the interval between dots is sparse, and the print density of the entire print becomes low, which is a problem in print quality.

On the other hand, as shown in FIG. 7, when the print medium 26 having a small outer diameter is rotated at the same angular velocity,
Since the moving speed on the outer peripheral surface of the print medium 26 becomes slow, if the ink discharge frequency from the discharge port of the print head 11 is constant, the print surface of the print medium 26 between one discharge and the next discharge is changed. The movement of the position is slight. As a result, in the print made on the outer peripheral surface of the print medium 26, the intervals between the dots are more dense than necessary, the print density of the entire print becomes very wide, and not only the print quality varies, but also the print quality becomes unnecessarily large. The formation of dense dots leads to waste of ink and also increases the running cost.

FIG. 5 shows a printing state in which the angular velocity is changed according to the outer diameter of the print medium 26 and the print medium 26 is rotated so that the peripheral velocity is constant. That is, even when the outer diameter of the print medium 26 is large,
Even if it is small, the print medium 26 may be rotated so that these peripheral velocities are constant.

Further, if the arrangement interval of the ejection openings of the print head 11 is p, it is necessary to make the dot density in the circumferential direction equal to the arrangement interval of the ejection openings.
Assuming that the ejection frequency (number of ejections per second) is f and the angular velocity of the print medium 26 is ω, ω = pf / r may be satisfied.

Therefore, when high quality printing is desired, for example, when it is desired to increase the vertical dot density to twice the horizontal dot density,
ω = pf / 2r, and conversely, when the printing speed is more important than the printing quality, the angular velocity ω may be reduced.
It is possible to always provide uniform and good printing quality.

Next, the print medium 2 for which printing has been completed
The discharging method of No. 6 will be described with reference to FIG.

When printing is completed over the entire circumference of the print medium 26, the rotation of the medium rotation motor 23 is stopped.
The work base 14 is lowered and a pair of gripping disks 25
a, 25b are returned to the positions where they sandwiched and supported both ends of the print medium 26. Then, the detachable motor 16
To rotate the feed screw shaft 20 in the reverse direction, whereby the slide block 21 moves in a direction away from the print medium 26, and releases the print medium 26 from the pair of gripping disks 25a, 25b. The pair of inclined surfaces 27a, 27b of the medium transfer block 27
To be supported by

The medium transfer block 27 supporting the print medium 26 is tilted from a position indicated by a solid line in FIG. 4 to a position indicated by a two-dot chain line in FIG. Drop it. The discharge belt 34 is stretched between a discharge belt driving roller 35 and a discharge belt driven roller (not shown), and is discharged by continuous or intermittent rotation of the discharge belt driving roller 35 clockwise in the drawing. It is supposed to be. A plurality of projections 34a are provided on the discharge belt 34 at regular intervals so that the discharged print medium 26 does not roll. The printed print medium 26 placed on the discharge belt 34 is sent out of the machine by the travel of the discharge belt 34.

FIG. 8 shows the print medium 26 as described above.
Medium rotation motor 2 during printing according to the outer diameter of
3 simply illustrates an image processing method when the angular velocity is changed. Reference numeral 36 denotes an image processing device which plays a role of creating and transferring print data to be applied to the print medium 26. A is the print data in the expanded state.
B corresponds to a print medium 26 having a relatively small outer diameter, and B represents a print medium 26 having a relatively large outer diameter.
It corresponds to.

In this case, as a matter of course, the peripheral length (in FIG. 8, represented by the length in the up-down direction) of the print medium 26 differs depending on the outer diameter of the print medium 26. Assuming that the pi is π, the circumferential length of the print medium 26 is 2πr, but the same print data is used for the print medium 26 having a large outer diameter and the print medium 26 having a small outer diameter. If so, the continuity of the image at the print start position is broken. For example, when an oblique stripe pattern as shown in FIG. 8 is to be printed around the print medium 26, if the width of the image data matches the circumference of the print medium 26, this stripe pattern extends over the entire circumference. Is continuous. However, if the width of the image data is longer than the circumference of the print medium 26, the stripe pattern has a step at the print start position, and the continuity of the image is broken. Conversely, if the width of the image data is shorter than the circumference of the print medium 26, the stripe pattern is insufficient to print the entire circumference,
A blank part occurs.

Therefore, when the radius r of the print medium 26 is measured, the image data to be printed is extended or reduced, and the width of the image data is adjusted so as to match the circumference 2πr of the print medium 26. By processing the data, a continuous image print can always be obtained on the print medium 26.

In the embodiment described above, only one print head 11 is used, but it is of course possible to use a plurality of print heads to enable color printing.

FIG. 9 shows a schematic structure of another embodiment of the printing apparatus according to the present invention. The parts having the same functions as those in the previous embodiment are denoted by the same reference numerals, and the description thereof will not be repeated. It shall be omitted. That is, the head holder 1
2 includes a plurality of print heads 11a, 11b, corresponding to inks of yellow, magenta, cyan, and black, respectively.
11c and 11d are attached to each other by a distance corresponding to the arrangement length of the discharge ports. Then, the image print data of each color is delayed by two columns, so that yellow, magenta,
By sequentially transferring cyan and black in this order, color printing on the outer peripheral surface of the print medium 26 can be easily performed.

It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for discharging a liquid, particularly in an ink jet system. This provides an excellent effect in an ink jet printer of a type in which a change in the state of a liquid is caused by thermal energy.
According to such a method, it is possible to achieve higher density and higher definition of the print.

The typical configuration and principle are described in, for example, US Pat. No. 4,723,129 and US Pat.
It is preferable to use the basic principle disclosed in Japanese Patent Application No. 0796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or the flow path holding the liquid. Applying at least one drive signal to the electrothermal transducer that provides a rapid temperature rise exceeding nucleate boiling corresponding to the print information, thereby generating thermal energy in the electrothermal transducer and providing a thermal effect to the inkjet head. This is effective because film boiling occurs on the surface, and consequently, bubbles in the liquid corresponding to this drive signal can be formed one-to-one. By the growth and shrinkage of the bubble, the liquid is discharged through the discharge port to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of the liquid having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. In addition,
US Patent No. 4 of the invention relating to the rate of temperature rise of the heat acting surface
By employing the conditions described in the specification of Japanese Patent No. 313124, more excellent printing can be performed.

The structure of the ink jet head is a combination of a discharge port, a flow path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned specifications. In addition, the present invention includes a configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting portion is arranged in a bent region. In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. JP-A-59-138461 which discloses a configuration corresponding to a discharge section
The effects of the present invention are effective even if the configuration is based on the above publication. That is, according to the present invention, printing can be performed reliably and efficiently regardless of the form of the inkjet head.

It is preferable to add an ejection recovery means for the ink jet head, a preliminary auxiliary means, and the like as the constitution of the ink jet apparatus of the present invention since the effect of the present invention can be further stabilized. Specific examples include capping means for the ink jet head, cleaning means, pressurizing or sucking means, an auxiliary heating element using an electrothermal transducer, another heating element, or a combination thereof. Examples of the heating unit include a preliminary ejection unit that performs ejection different from printing.

Regarding the type and number of ink jet heads to be mounted, for example, only one ink jet head is provided corresponding to a single color ink, and a plurality of inks having different print colors and densities are used. A plurality may be provided. That is, for example, the print mode of the inkjet apparatus is not limited to the print mode of only the mainstream color such as black, but may be either an integrated inkjet head or a combination of a plurality of inkjet heads. The present invention is also very effective for an apparatus provided with at least one of the full-color print modes using mixed colors. In this case, it is also effective to discharge a processing liquid (printability improving liquid) for adjusting the printability of the ink according to the print medium from the inkjet head to the print medium.

In addition, in the embodiment of the present invention described above, a material which solidifies at room temperature or lower and softens or liquefies at room temperature may be used. In general, the temperature is controlled within the range of not more than ° C. and the temperature is controlled so that the viscosity of the liquid is in a stable ejection range. In addition, in order to positively prevent the temperature rise due to thermal energy by using it as the energy of the state change from the solid state to the liquid state, or to prevent the evaporation of the liquid,
What solidifies in a standing state and liquefies by heating may be used. In any case, the liquid is liquefied by the application of the thermal energy according to the print signal, and is liquefied only by the application of the thermal energy, such as the one from which the liquid is ejected and the one which already starts to solidify when reaching the print medium. The present invention can be applied to the case of using a material having a property. The liquid in such a case is disclosed in JP-A-54-56847.
JP-A No. 60-71260 or JP-A-60-71260, in a state in which the porous sheet is held as a liquid or solid substance in a concave portion or a through-hole and faces the electrothermal converter. Is also good. In the present invention,
The most effective one for each of the above-mentioned liquids is to execute the above-mentioned film boiling method.

In addition, the form of the printer according to the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also a copying apparatus combined with a reader, a facsimile apparatus having a transmission / reception function, and the like. It may be one that takes the form of a printing device.

[0063]

According to the printing apparatus of the present invention, the radius of curvature of the print surface of the print medium is detected by the print surface measurement means, and the rotational speed of the print medium by the medium rotation means is determined based on the detection result by the print surface measurement means. Is controlled by the control means, so that very high-quality prints and quick prints can be obtained as desired.

Further, printing can be performed directly on the printing surface of a printing medium without using a method that requires a printing plate such as screen printing, and printing operations for various types of printing media can be performed in a small amount in a conventional manner. It can be more simplified.

Further, the radius of curvature of the print surface of the print medium is detected by the print surface measuring means, and based on the detection result by the print surface measuring means, the width of the image data along the circumferential direction of the print surface by the image processing unit. Is made to correspond to the circumference of the print surface, so that even if the outer diameter of the print medium is different, continuous image printing can be performed at all times, and uniform and good print with no decrease in print density It can be performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a main part of an embodiment of a printing apparatus according to the present invention, together with FIG.

FIG. 2 is a perspective view showing an appearance of a main part of an embodiment of a printing apparatus according to the present invention, together with FIG.

FIG. 3 is a conceptual diagram showing a print medium transport system in the embodiment of the present invention, together with FIG.

FIG. 4 is a conceptual diagram showing a print medium transport system in the embodiment of the present invention, together with FIG.

FIG. 5 is a conceptual diagram showing an example of a dot pattern formed on a print surface of a print medium together with FIGS. 6 and 7.

6 is a conceptual diagram showing an example of a dot pattern formed on a print surface of a print medium together with FIGS. 5 and 7. FIG.

FIG. 7 is a conceptual diagram showing an example of a dot pattern formed on a print surface of a print medium together with FIG. 5 and FIG.

FIG. 8 is a conceptual diagram illustrating an appearance of an image processing apparatus according to an embodiment of the present invention.

FIG. 9 is a perspective view illustrating an appearance of a main part of another embodiment of the printing apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Print head 12 Head holder 13 Holder guide 14 Work base 15a, 15b Base guide 16 Detachable motor 17 Detachable motor bracket 18 Bearing 19 Bearing bracket 20 Feed screw shaft 21 Slide block 22 Medium rotation motor bracket 23 Medium rotation motor 24 Coupler 25a, 25b Grip disk 26 Print medium 27 Medium transfer block 27a, 27b Inclined surface 28 Transfer block swing axis 29 Media transport belt 29a Projection 30 Belt drive roller 31 Measurement block swing axis 32 Measurement block 32a, 32b Inclined surface 33 Touch Sensor 34 Discharge belt 34a Projection 35 Discharge belt drive roller 36 Image processing device

Claims (10)

[Claims] 1. A medium holding means for holding a print medium having a print surface with a predetermined radius of curvature, a medium rotating means for driving and rotating the medium hold means around a center of curvature of the print surface of the print medium, and the print A print head that faces the print surface of the medium and prints on the print surface; a print surface measurement unit that detects a radius of curvature of the print surface of the print medium; and Control means for controlling a rotation angular velocity of the print medium by the medium rotation means. 2. The printing apparatus according to claim 1, wherein the control unit controls the peripheral speed of the print medium at a constant speed regardless of the radius of curvature of the print surface. . 3. A medium holding means for holding a print medium having a print surface with a predetermined radius of curvature, a medium rotating means for driving and rotating the medium hold means, and a print surface facing the print surface of the print medium. A print head for performing printing on the print medium; a print surface measuring means for detecting a radius of curvature of the print surface of the print medium; a center of curvature of the print medium and the medium gripping obtained based on a detection result by the print surface measurement means. And a medium positioning means for supplying the print medium to the medium gripping means so that the rotation center of the means coincides with the rotation center of the means. 4. A medium holding means for holding a print medium having a print surface with a predetermined radius of curvature, a medium rotating means for driving and rotating the medium hold means around a center of curvature of the print surface of the print medium, and A print head that faces the print surface of the medium and prints on the print surface; a print surface measurement unit that detects a radius of curvature of the print surface of the print medium; and A printing apparatus, comprising: an image processing unit for making a width of image data along a circumferential direction of the print surface correspond to a circumferential length of the print surface. 5. A head position adjusting means for driving the print head in a direction facing the print surface of the print medium, and the print surface of the print medium and the print based on a detection result by the print surface measurement means. The printing apparatus according to any one of claims 1 to 4, further comprising control means for controlling the operation of the head position adjusting means so that the distance from the head is a predetermined distance. 6. The printing surface measuring means includes a V-block having a pair of inclined surfaces intersecting each other, and a sensor for detecting a distance between a printing surface of the printing medium held by the V-block. 2. The method according to claim 1, wherein
A printing apparatus according to any one of claims 1 to 5. 7. The printing apparatus according to claim 1, wherein the print medium has a cylindrical shape or a cylindrical shape. 8. The printing apparatus according to claim 1, wherein the print head has a discharge energy generating unit for discharging ink from a discharge port. 9. The printing apparatus according to claim 8, wherein the discharge energy generating section has an electrothermal converter that generates thermal energy. 10. The printing apparatus according to claim 8, wherein the discharge ports are arranged along a direction parallel to a rotation center of the medium gripping unit.