JP2000191171A - Picture image recording method and picture image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge a second piece by using its nature not to electrostatically attracted in the case of winding the two electrostatically attractive ones around a cylinder, to simplify a handling separation mechanism of a feeding system and to reduce a load of a surface of a recording sheet. SOLUTION: A picture image recording method has a feeding process to feed a recording sheet to a cylinder, a fixing process to firmly hold the fed recording sheet 1 on a holding surface of the cylinder 100 by electrostatic attraction while rotating the cylinder 100 in the feeding direction, an overlapped feeding discharge process to rotate the cylinder 100 so as to discharge the second and latter recording sheets 1 from the holding surface of the cylinder 100 while firmly holding the first recording sheet 1 closest to the holding surface of the cylinder 100 on the holding surface of the cylinder 100 by electrostatic attraction in the case where the recording sheets 1 are overlapped and fed and a picture image recording process to record a picture image on the recording sheet 1 firmly held on the holding surface of the cylinder 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image recording method and an image recording apparatus for recording an image on a recording sheet.

[0002]

2. Description of the Related Art In recent years, a color separation halftone original film image data, a photo halftone original image data and a solid image halftone original image data have been separated by a device called DTP, not by cutting and pasting a color separation halftone original film. From the image data such as, cut and paste on the image data, to create a color separation halftone document image data, using a device called an imagesetter to create a color separation halftone document film from this color separation halftone document image data, A printing plate is directly created by a device called CTP.

The proofing work performed by such a system using DTP includes not only a method of creating a color separation screen original film from color separation screen original image data and a method of forming a color proof from the color separation screen original film, DD that creates a color proof directly from color separation net document image data
CP has recently taken place.

In this DDCP, a silver halide color photographic light-sensitive material is LE based on color separation screen original image data.
Exposure by D or laser light, etc., to create a color proof, based on color separation screen original image data, to create a color proof by ink transfer printing method, based on color separation screen original image data, There is one that creates a color proof by an inkjet printing method.

[0005] In the case of producing a color proof by exposing a silver halide color photographic light-sensitive material,
There is a problem that it is necessary to use a processing liquid or a waste liquid of the processing liquid is generated. Further, in the ink transfer printing method, there is a problem that an ink sheet after transferring the ink is generated as a waste material.

[0006] On the other hand, those using the ink jet printing method record images by ejecting minute droplets of ink onto a recording sheet such as paper.
High-speed printing is possible, it is inexpensive, and there is little generation of waste liquid and waste material.

[0007] DDCPs using such an ink-jet printing method include Y (yellow), M
(Magenta), C (cyan) and K (black)
2. Description of the Related Art An ink jet printer provided with a print head is known. This ink jet printer has a cylinder holding a recording sheet on a holding surface, and a plurality of print heads provided with only one nozzle, and constantly ejects droplets from the nozzle at regular intervals, A continuous type of recording an image by deflecting the ejected droplets so that the image is recorded on the image recording surface of the recording sheet held in a cylinder, or is prevented from hitting the recording sheet. Met.

Although not for DDCP, Y, M,
An ink jet printer having a print head for each of the C and K colors. A single print head is provided with a plurality of nozzles, and these nozzles are used to print images on a recording sheet conveyed by a belt at high speed. Some records are also known. Note that the on-demand method is a method of recording an image corresponding to image data on a recording sheet by ejecting or not discharging a droplet according to image data.

[0009]

By the way, when a recording sheet is fixedly held on the outer peripheral surface of a cylinder and an image is recorded on the recording sheet, the recording sheet is fed one by one to the cylinder and wound. For example, if two or more recording sheets are fed in an overlapping manner, printing failure of an image or breakage of a print head due to a recording sheet separated during recording may occur. For this reason, it is conceivable to separate and feed the recording sheets one by one before feeding.

[0010] However, for example, a recording sheet for producing a color proof has a specially processed surface and a high coefficient of friction on the surface, so that the reliability of separation of the recording sheet tends to be low. In addition, if a cutting roller having a high frictional force is used or the number of times of cutting is increased in order to increase reliability, problems such as imprints on the surface and deterioration of printing quality have occurred. In addition, the thickness of the recording sheet varies depending on the application, and further, the separation reliability is lowered, which not only hinders recording of an image but also causes loss of the recording sheet.

The present invention has been made in view of the above point, and utilizes the property that, when two sheets of electrostatic adsorption are stacked and wound around a cylinder, the second and subsequent recording sheets from the cylinder do not electrostatically adsorb. An image recording method and an image recording apparatus capable of discharging the second and subsequent recording sheets, simplifying a cutting / separating mechanism of a feeding system, and reducing a load on the surface of the recording sheets. It is intended to be.

[0012]

The present invention will be described below.
In addition, unless otherwise specified, each component described in each claim is not limited to one composed of one member, and may be composed of a plurality of members. It goes without saying that a plurality of components may be used.

According to the first aspect of the present invention, there is provided a "feeding process of feeding a recording sheet to a cylinder, and, while rotating the cylinder in a feeding direction, holding the fed recording sheet by electrostatic attraction. A fixing process of fixedly holding the recording sheet on the holding surface, and when a recording sheet is double-fed, the first recording sheet closest to the holding surface of the cylinder is fixed to the holding surface of the cylinder by electrostatic attraction. A double feeding / discharging process in which the cylinder is rotated so as to discharge the second or more recording sheets from the holding surface of the cylinder while holding the recording sheet on the top, and holding the recording sheet fixedly on the holding surface of the cylinder An image recording step of recording an image on a recorded recording sheet. ].

According to the first aspect of the present invention, the first recording sheet closest to the holding surface of the cylinder is fixedly held on the holding surface of the cylinder by electrostatic attraction, and Since the second or more recording sheets are not sucked from the holding surface of the cylinder, the second or more fed recording sheets can be smoothly discharged. An image can be favorably recorded on a sheet.

Further, since the reliability of separation of the fed recording sheet may be low, the mechanism for separating the recording sheet during feeding can be simplified, the cost can be reduced, and indentations can be formed on the surface of the recording sheet. Also, it is possible to suppress scratches or the like that deteriorate the printing quality.

According to a second aspect of the present invention, there is provided the image recording method according to the first aspect, wherein the recording sheet is brought into close contact with the holding surface of the cylinder by a pressing roller in the fixing step. ].

According to the second aspect of the present invention, the recording sheet fed onto the holding surface of the cylinder is pressed against the holding surface of the cylinder by the pressing roller. The fixed holding of the first recording sheet that is closest to the first recording sheet by suction is stabilized, and the second or more recording sheets fed by double feeding can be discharged more smoothly.
Even if the recording sheets are multi-fed, an image can be recorded more favorably on the recording sheets.

According to a third aspect of the present invention, there is provided the image recording apparatus according to the first or second aspect, wherein in the double feed discharging step, the cylinder is rotated in a discharging direction opposite to the feeding direction. Method. ].

According to the third aspect of the present invention, the second or more recording sheets from the holding surface of the cylinder are turned on the holding surface of the cylinder by rotating the cylinder in the discharge direction opposite to the feeding direction. Therefore, it is easy to stably perform the feeding of the recording sheets and the discharging of the second or more recording sheets that have been multi-fed, and the mechanism for these can be simplified.

According to a fourth aspect of the present invention, there is provided a method according to the first aspect, wherein after the image recording step, the electrostatic attraction is released and the recording sheet is discharged from the holding surface of the cylinder.
4. The image recording method according to any one of 3. ].

According to the present invention, the recording sheet on which the image is recorded can be smoothly discharged.

According to a fifth aspect of the present invention, there is provided an image recording method according to the fourth aspect, wherein the recording sheet is discharged from a holding surface of the cylinder while rotating the cylinder in the discharging direction. . ].

According to the fifth aspect of the present invention, the recording sheet on which the image is recorded is discharged from the holding surface of the cylinder by rotating the cylinder in the discharge direction opposite to the feeding direction. It is easy to stably feed the sheet and discharge the recording sheet on which the image is recorded, and the mechanism for these can be simplified.

According to a sixth aspect of the present invention, there is provided an image forming apparatus according to the first aspect, wherein an image is recorded on the recording sheet by ejecting ink droplets imagewise from a print head.
The image recording method according to any one of the above items. ].

According to the sixth aspect of the present invention, it is possible to prevent the double-fed recording sheet from being separated in the middle and damaging the print head that ejects ink droplets.

According to a seventh aspect of the present invention, there is provided an apparatus according to the sixth aspect, wherein the print head is an on-demand type print head in which a plurality of nozzles for ejecting ink droplets are arranged in parallel. Image recording method. ].

According to the seventh aspect of the invention, it is possible to prevent the multi-fed recording sheet from being separated on the way, so that the distance between the leading end of the print head and the recording sheet held on the holding surface of the cylinder is reduced. Because it can be made narrower, the amount of waste ink is small and image recording can be performed at high speed.However, even when using an on-demand type print head provided with a plurality of nozzles in which the ejection direction of ink droplets is not so fixed, image recording on a recording sheet The positional accuracy of ink droplets recorded on the surface can be increased, and a fine image with high reproducibility can be recorded.

[0028] The invention according to claim 8 is characterized in that a color proof image corresponding to the color separation image data is recorded on the recording sheet in accordance with the image data corresponding to the color separation image data. The image recording method according to claim 7, wherein ].

According to the eighth aspect of the invention, since a fine image with high reproducibility can be recorded, a color proof used for proofreading can be satisfactorily created.

According to a ninth aspect of the present invention, there is provided a cylinder for holding the recording sheet fed by the sheet feeding means fixedly on a holding surface by electrostatic attraction, and feeding the recording sheet to the cylinder. An image recording apparatus comprising: a sheet feeding unit for feeding a sheet; and a cylinder rotating unit for rotating the cylinder. The image recording apparatus records an image on a recording sheet fixedly held on a holding surface of the cylinder. While rotating the cylinder in the feeding direction by the moving means, the recording sheet fed by the sheet feeding means was fixedly held on the holding surface of the cylinder by electrostatic attraction, and the recording sheet was double-fed. In this case, while the first recording sheet closest to the holding surface of the cylinder is fixedly held on the holding surface of the cylinder by electrostatic suction, the second or more recording sheets are held on the holding surface of the cylinder. So that the cylindrical rotating hand Turn the cylinder by, then
An image recording apparatus for recording an image on a recording sheet fixedly held on a holding surface of the cylinder. ].

According to the ninth aspect of the present invention, the first recording sheet closest to the holding surface of the cylinder is fixedly held on the holding surface of the cylinder by electrostatic attraction, and Since the second or more recording sheets are not sucked from the holding surface of the cylinder, the second or more fed recording sheets can be smoothly discharged. An image can be favorably recorded on a sheet.

Also, since the reliability of separation of the fed recording sheet may be low, the mechanism for separating the recording sheet during feeding can be simplified, the cost can be reduced, and indentations can be formed on the surface of the recording sheet. Also, it is possible to suppress scratches or the like that deteriorate the printing quality.

According to a tenth aspect of the present invention, there is provided an image forming apparatus comprising the steps of: while rotating the cylinder in the feeding direction, holding the fed recording sheet fixedly on the holding surface of the cylinder by electrostatic attraction; The image recording apparatus according to claim 9, further comprising a pressing roller for bringing a sheet into close contact with a holding surface of the cylinder. ].

According to the tenth aspect of the present invention, the recording sheet fed onto the holding surface of the cylinder is pressed against the holding surface of the cylinder by the pressing roller. The fixed holding of the closest first recording sheet by suction is stabilized, and the second or more recording sheets that have been multi-fed can be discharged more smoothly. Also, an image can be favorably recorded on a recording sheet.

According to an eleventh aspect of the present invention, there is provided a method as described above, wherein when a recording sheet is multi-fed, a second recording sheet is fixedly held on the holding surface of the cylinder by electrostatic attraction. 11. The method according to claim 9, wherein, in the step of rotating the cylinder so as to discharge the recording sheet from the holding surface of the cylinder, the cylinder is rotated in a discharge direction opposite to the feeding direction. Image recording device. ].

According to the eleventh aspect of the present invention, by rotating the cylinder in the discharge direction opposite to the feed direction,
Since the second or more recording sheets are discharged from the holding surface of the cylinder from the holding surface of the cylinder, it is possible to stably feed the recording sheets and discharge the second or more recording sheets fed double. And the mechanism for these can be simplified.

According to a twelfth aspect of the present invention, there is provided an image forming apparatus, comprising: a sheet discharging means for discharging a recording sheet from the holding surface of the cylinder; The image recording apparatus according to claim 9, wherein after recording, the electrostatic attraction is released, and the recording sheet is discharged from the holding surface of the cylinder by the sheet discharging unit. . ].

According to the twelfth aspect of the present invention, a recording sheet on which an image is recorded can be smoothly discharged.

The invention according to claim 13 is characterized in that the sheet discharging means discharges a recording sheet from the holding surface of the cylinder without rubbing the image recording surface. 13. The image recording device according to item 12. ].

According to the thirteenth aspect of the present invention, since the recording sheet can be discharged without rubbing the image recording surface, the recording sheet is easily damaged and can record a high-density image such that a large amount of ink is absorbed per unit area. However, damage due to discharge can be prevented.

According to a fourteenth aspect of the present invention, there is provided the image recording apparatus according to the thirteenth aspect, wherein the recording sheet is discharged from a holding surface of the cylinder while rotating the cylinder in the discharging direction. . ].

According to the fourteenth aspect of the present invention, by rotating the cylinder in the discharging direction opposite to the feeding direction,
Since the recording sheet on which the image is recorded is discharged from the holding surface of the cylinder, it is easy to stably feed the recording sheet and discharge the recording sheet on which the image is recorded. Can be simplified.

According to a fifteenth aspect of the present invention, there is provided an image forming apparatus comprising: a printing head for ejecting ink droplets, wherein an image is recorded on the recording sheet by ejecting ink droplets imagewise from the printhead. The image recording apparatus according to any one of claims 9 to 14, wherein ].

According to the fifteenth aspect of the present invention, it is possible to prevent a double-fed recording sheet from being separated in the middle and damaging a print head that ejects ink droplets imagewise.

According to a sixteenth aspect of the present invention, there is provided an apparatus according to the fifteenth aspect, wherein the print head is an on-demand type print head in which a plurality of nozzles for ejecting ink droplets are arranged in parallel. Image recording device. ].

According to the sixteenth aspect of the invention, it is possible to prevent the multi-fed recording sheet from being separated on the way, so that the distance between the leading end of the print head and the recording sheet held on the holding surface of the cylinder is reduced. Even when using an on-demand print head provided with a plurality of nozzles that can be narrowed, the amount of waste liquid of ink is small, and the ink droplet ejection direction is not very constant, but the ink droplet ejection direction is not so constant, the ink droplet is ejected from the print head, The positional accuracy of ink droplets recorded on the image recording surface of the recording sheet can be increased, and a fine image with high reproducibility can be recorded.

According to a seventeenth aspect of the present invention, there is provided a method as described above, wherein the holding surface of the cylinder has a substantially cylindrical shape, and the cylinder rotating means rotates the cylinder substantially about the cylinder axis. The image recording apparatus according to claim 16, wherein: ].

According to the seventeenth aspect of the present invention, since the cylinder rotates around the axis of the cylinder while the recording sheet is fixedly held on the cylindrical holding surface, image recording on the recording sheet is performed. Since the surface passes through a predetermined position in a predetermined direction, the interval between the tip of the print head and the image recording surface of the recording sheet can be made very small, and the mounting position of the print head with respect to the image recording surface of the recording sheet and Even when using an on-demand print head equipped with a plurality of nozzles that can provide extremely high precision in the direction and the ejection direction of ink droplets is not very constant, the ink is ejected from the print head and recorded on the image recording surface of the recording sheet Since the positional accuracy of the ink droplets to be used can be made extremely high, it is possible to record a highly reproducible high-definition image.

According to an eighteenth aspect of the present invention, there is provided a method as described above, wherein the column axis of the columnar surface is substantially horizontal, and the print head discharges ink droplets downward from a position above a recording sheet to perform the recording. 18. The image recording apparatus according to claim 17, wherein an image is recorded on a sheet. ].

According to the eighteenth aspect of the present invention, the cylinder axis of the cylinder is substantially horizontal, and the print head discharges ink droplets downward from a position above the recording sheet, thereby forming the recording sheet. Since the image is recorded on the recording sheet, the print head ejects ink droplets in an upward or horizontal direction, compared with a case where an image is recorded on a recording sheet held by the cylinder, and is ejected from the print head, Since the positional accuracy of the ink droplets to be recorded on the image can be further improved, it is possible to record a highly reproducible high-definition image.

In addition, even if the cylinder is a large cylinder for holding a large-size recording sheet for color proof, even if the horizontal cross-sectional area of the structural material for improving the accuracy between the cylinder and the print head is small. Good images can be recorded while reducing the cost of the entire apparatus.

According to a nineteenth aspect of the invention, there is provided a moving means capable of moving the print head in a direction parallel to the cylinder axis over at least an image recording width, wherein the plurality of nozzles 19. The image forming apparatus according to claim 15, wherein the plurality of nozzles are arranged side by side in a direction substantially parallel to an axis, and a width (arranged width) in which the plurality of nozzles are arranged side by side is smaller than an image recording width. The image recording device according to claim 1. ].

According to the nineteenth aspect of the present invention, since the plurality of nozzles are juxtaposed in a direction substantially parallel to the cylinder axis, the height of the plurality of nozzles with respect to the image recording surface and Since it is easy to reduce the variation in the direction and the width in which the plurality of nozzles are arranged side by side is narrower than the image recording width, the number of nozzles is smaller than the number of nozzles arranged side by side over this image recording width. It is easy to create a print head with the required accuracy, and the holding means can move the print head in a direction parallel to the cylinder axis over an image recording width, so that the image is recorded over the entire image recording area of the recording sheet. Can be recorded, and it is cheaper and more accurate than when a plurality of print heads are arranged so as to cover the entire image recording width. Therefore, the cost of the entire apparatus can be reduced while a better image can be recorded.

According to a twentieth aspect of the present invention, there is provided an image recording apparatus according to the nineteenth aspect, further comprising a regulating means for regulating a position of the print head in a direction perpendicular to the cylindrical axis. ].

According to the twentieth aspect, not only can the position of the print head in the direction perpendicular to the cylinder axis of the cylinder be regulated, but also the position of the print head in the direction of the cylinder axis can be easily regulated. It is easy to prevent the position of the image recorded on the recording sheet from being slightly shifted before and after moving in the direction parallel to the cylinder axis. Therefore, a better image can be recorded.

It is sufficient that the regulating means regulates the position of the print head in the direction perpendicular to the column axis. For example, a column guide provided in parallel with the cylinder axis of the cylinder; This guide is fitted, and a combination with a holding member that holds the print head, a guide groove provided in parallel with the cylindrical axis of the cylinder, and a holding member that fits in the guide groove and holds the print head. But not limited to these. Further, examples of the column shape include a prism shape such as a quadrangular prism shape, a column shape, and the like, but are not limited thereto.

The invention according to claim 21 is characterized in that the sheet feeding means feeds a recording sheet onto the holding surface of the cylinder without rubbing an image recording surface. The image recording device according to claim 9. ].

The invention according to claim 22 is characterized in that the sheet feeding means has a guide for guiding the back side of the recording sheet, and a feed roller pair for feeding the recording sheet. The image recording device according to claim 21. ].

According to the present invention, since the image can be fed without rubbing the image recording surface, it is possible to record a high-density image such that a large amount of ink is absorbed per unit area. Even a sheet can be prevented from being damaged by feeding.

According to a twenty-third aspect of the present invention, a color proof image corresponding to the color separation image data is recorded on the recording sheet in accordance with image data corresponding to the color separation image data. The image recording apparatus according to any one of claims 9 to 21. ].

According to the twenty-third aspect of the present invention, since a fine image with high reproducibility can be recorded, a color proof used for proofreading can be created well.

According to a twenty-fourth aspect of the present invention, there is provided the image recording apparatus according to the twenty-third aspect, wherein the print head is provided for each primary color of the color separation halftone image data. ].

According to the twenty-fourth aspect of the present invention, since the print head is provided for each primary color of color-separated halftone image data, one printhead is provided for all primary colors of color-separated halftone image data. Since an image can be recorded at a higher speed even if the number of nozzles per print head is smaller than that provided with nozzles, the image recording speed is high and a print head can be easily created. Therefore, the cost of the entire apparatus can be reduced while the color proof can be created more quickly.

In the present invention, the holding surface for holding the recording sheet fixedly is the outer circumferential surface of the cylinder. Then, when the holding surface is the outer peripheral surface of the cylinder, it is desirable to hold the image so that the image recording surface of the recording sheet faces outward,
Not limited to this.

Further, the cylindrical axis and the cylindrical surface are a cylindrical axis and a cylindrical surface in a geometric sense, and the cylindrical axis is a straight line.
The cylindrical surface is a surface formed by a straight line parallel to the cylinder axis and passing through a circumference on a plane perpendicular to the cylinder axis.

The term “holding surface” refers to a surface at a location where the recording sheet is held in the area for holding the recording sheet, and the term “substantially cylindrical” means that the holding surface is substantially cylindrical. The location where the recording sheet is held may be substantially a cylindrical surface, and the other areas may be concave or substantially non-cylindrical, such as not being present, or substantially not. It may be a cylindrical surface. Further, the recording sheet may be held at all points in the area for holding the recording sheet, but for example, the recording sheet such as a groove, a hole, a slit, or a hole is not held in a part of the area for holding the recording sheet. Even if the location is provided, the location for holding the recording sheet in the area for holding the recording sheet may be a substantially cylindrical surface.

The fact that the holding surface is substantially a cylindrical surface means that the variation in the distance of the holding surface with respect to the cylindrical axis does not substantially cause a problem in producing a color proof that can be favorably used for calibration. By being within the range, the variation of the distance of the holding surface with respect to the cylindrical axis is preferably within 0.5 mm or less, and more preferably within 0.3 mm or less (especially 0.1 mm or less).

In addition, the term “substantially rotating around the cylindrical axis of the cylindrical surface” means to rotate around the cylindrical axis in the geometrical meaning of the cylindrical surface as a rotation axis, and to carry out eccentricity (distance of the rotation axis with respect to the cylindrical axis). ) Is within a range that does not substantially cause a problem in producing a color proof that can be favorably used for proofreading, and the eccentricity is preferably within 0.5 mm or less, more preferably 0.3 mm or less. (Especially, 0.1 mm or less).

The direction of the axis of the cylinder is preferably substantially horizontal, but may be vertical or oblique.

The distance between the print head and the recording sheet is preferably restricted to 1 cm or less, and more preferably to 2 mm or less (particularly 1 mm or less).

Also, that the cylinder axis of the cylinder is substantially horizontal means that
It is sufficient that the horizontal cross-sectional area of the structural material for increasing the accuracy between the cylinder and the print head is small, and it is sufficient that the position accuracy of the ink droplets is higher. Absent. The angle of the axis of the cylinder with respect to the horizontal plane is preferably 20 ° or less, and more preferably 5 ° or less (especially 1 ° or less).

Further, discharging ink droplets downward means that
It is sufficient that the ink droplet is ejected in a downward direction so as to increase the positional accuracy of the ink droplet, and it is not necessary to be completely vertically downward. The angle of the direction in which the ink droplets are ejected with respect to the vertically downward direction is preferably equal to or less than a half-perpendicular angle, and more preferably equal to or less than 20 ° (particularly, equal to or less than 5 °).

Further, that a plurality of nozzles are juxtaposed in a direction substantially parallel to the cylinder axis means that the direction in which the plurality of nozzles are arranged and the cylinder axis are completely parallel. However, the direction in which the plurality of nozzles are arranged and the column axis may be substantially parallel to such an extent that variations in height and direction of the plurality of nozzles with respect to the image recording surface can be reduced. The deviation angle φ between the direction in which a plurality of nozzles are arranged and the direction of the cylinder axis is determined by the width of the plurality of nozzles arranged in the circumferential direction of the cylinder (the direction in which the plurality of nozzles are arranged). (W) from the center of the nozzle at one end to the center of the nozzle at the other end).

Φ <tan ⁻¹ (S / W) As a result, a high-quality color proof can be created without performing image processing for deforming an image. Further, it is preferable that the following expression is further satisfied.

Φ <tan ⁻¹ (0.3 × S / W) The color proof image corresponding to the color separation halftone image data is a color proof image that simulates a printed matter created from the color separation halftone image data. That is. Also,
The image data corresponding to the color separation halftone image data may be image data corresponding to the color separation halftone image data, and is not limited to the color separation halftone image data itself. A continuous tone image processing apparatus for converting halftone original image data or color separation halftone image data input to a halftone image processing apparatus for generating halftone image data into a continuous tone image data. The image data may be continuous tone image data obtained by converting the image data.

[0076]

Embodiments of the present invention will be described below. The present invention is not limited to the embodiments described below. In the following description, there may be a description explaining the meaning of the term, but it is merely to explain the meaning of the term in the embodiment, and the meaning of the term of the present invention is not limited to this description. . Embodiment An image recording apparatus according to this embodiment is an image recording apparatus capable of recording a color proof image by discharging ink droplets on an image recording surface of a recording sheet based on color separation halftone image data. FIG. 1 is a schematic perspective view of the internal structure of the image recording apparatus of this embodiment, FIG. 2 is a schematic sectional view of the image recording apparatus, and FIG. 3 is a view of the print head viewed from the ejection direction. A description will be given based on this.

As a recording sheet 1 on which an image is recorded by the image recording apparatus of this embodiment,
It is preferable that an ink absorbing layer having a large amount of ink absorbed per unit area is provided, thereby enabling good tone reproduction from high density to low density. The ink absorbing layer is preferably a void layer containing inorganic fine particles and a binder. The back surface opposite to the image recording surface of the recording sheet 1 is preferably a slippery surface.

The sheet cassette 500 can stack and store a plurality of recording sheets 1 so that the image recording surface faces upward. Then, a feeding roller 4 to be described later
10 is fed from the uppermost recording sheet 1 of the plurality of recording sheets that have been deposited.

In the image recording apparatus of this embodiment, the recording sheets 1 are taken out one by one from the sheet cassette 500, supplied to the cylinder 100, and the recording sheet 1 is held on the holding surface of the cylinder 100. While holding the recording sheet 1 on the upper side and rotating the cylinder 100 at a constant rotation speed as main scanning, based on continuous tone image data obtained by performing continuous tone conversion of color separation halftone image data. By ejecting ink droplets from the print head 200, the cylinder 1
00, a color proof image corresponding to the color separation halftone image data is recorded on the image recording surface of the recording sheet fixedly held on the outer peripheral surface of the recording sheet 1, and the recording sheet 1 on which the color proof image is recorded is discharged to the discharge tray 310. Is what you do.

Then, the image recording apparatus of this embodiment
The recording sheet 1 is supplied to the cylinder 100 from the sheet cassette 500 disposed below the cylinder 100 and the discharge tray 310. Only one recording sheet stacked on the top of the sheet cassette 500 is separated by a difference in frictional force. Roller 410 that feeds the recording sheet 1 while feeding, a first pair of conveying rollers 420 that conveys the recording sheet 1 sent from the feeding roller 410, and a back surface of the recording sheet 1 that is sent by the first conveying roller pair 420. A first supply guide 430 for guiding;
A second conveying roller pair 440 that conveys the recording sheet 1 sent along the first supply guide 430, and a second supply guide 450 that guides the back surface of the recording sheet 1 sent by the second conveying roller pair 440. And a pressing roller 460 for pressing the recording sheet 1 sent along the second supply guide 450 onto the holding surface of the cylinder 100 to make the recording sheet 1 adhere to the holding surface of the cylinder 100. Is transported and supplied while being turned upside down. When the recording sheet 1 is supplied to the cylinder 100, the pressing roller 460 is pressed against the cylinder 100. However, when the recording sheet 1 is fixedly held on the cylinder 100, the pressing on the cylinder 100 is released. Detach from the cylinder 100.

The cylinder 100 has a holding surface on the outer peripheral side for fixedly holding the recording sheet 1 wound around the recording sheet 1 with the image recording surface facing outward during image recording.
The shape of the holding surface of the cylinder 100 is a cylindrical surface, and the dispersion of the distance of the holding surface with respect to the cylindrical axis is 0.05.
mm. And this cylinder 100
The cylindrical axis of the holding surface of the cylindrical surface is arranged so as to be horizontal, and to rotate about this cylindrical axis.
It is within 1 mm. The cylinder 100 is rotated by a motor (not shown) at a constant rotation speed of 500 rpm or more (for example, 800 rpm) while the recording sheet 1 is fixedly held during image recording.

The carriage 230 fixedly holds the print head 200. The print head 200 is an on-demand type print head, and as shown in FIG.
3, 215, and 217 are provided, and two nozzle heads are provided on each of the nozzle head stands 211, 213, 215, and 217. Then, the nozzle head 22
Each of the nozzles 1 to 228 is provided with a plurality of nozzles 220 arranged in the column axis direction of the cylinder 100 so that all the deviation angles φ satisfy the following equation within a range narrower than the image recording width. I have.

Formula: φ <tan ^-1 (0.3 × S / W) These nozzles 220 are ink jet nozzles of an on-demand type, which discharge ink droplets only to pixels for which ink recording is required. And ejects ink droplets vertically downward.

The print head 2 is controlled while the position of the print head 200 in the direction perpendicular to the cylinder axis of the cylinder 100 is regulated.
00 is provided in the direction of the cylinder axis of the cylinder 100.
The carriage guide 245 is provided with a rectangular column-shaped hole into which the carriage guide 245 is slidably fitted.
Pulley 250 fixed to the motor shaft
And a carriage 23 on a stainless steel belt 260 fitted over a pulley 270 held rotatably.
0 is fixed, and the motor 240 rotates the pulley 250 so that the carriage guide 245 guides the carriage 230 and the print head 200
The carriage 230 can be moved in the direction of the cylinder axis of the cylinder 100 over a width wider than the image recording width so that the carriage 230 is always positioned vertically above the cylinder axis of the cylinder surface of the cylinder 00.

Further, ink containers 271 to 278 are provided on the ink container holding plate 280 for each of the nozzle heads 221 to 228. Then, the nozzle heads 221 to 22
8 and the corresponding ink containers 271 to 278, the nozzle heads 221 to 228 and the corresponding ink containers 271 to 278 are connected to the flexible pipes 291 and 292, respectively.
Connected through. The pipe 292 has one end on the carriage 230 and the other end on the ink container holding plate 28.
It is connected through a tractor unit 295 fixed to zero. The pipe 291 has one end connected to the tractor unit 295 and the other end connected to the ink containers 271 to 278.

[0086] Before image recording, the maintenance unit 600 moves the print head 2 positioned above it.
The sucking of the ink from the nozzles 220 of the print head 200 is performed by covering the ink ejection surface of No. 00 with a cap for sucking to reduce the pressure, and the cleaning is performed by cleaning the ink ejection surface of the print head 200 after the sucking with a wiper or the like.

Then, as described above, the recording sheet 1 is fixedly held at a predetermined position on the holding surface of the cylinder 100. When the motor 240 rotates the pulley 250, the carriage 230 is moved in the cylindrical axis direction of the cylinder 100, and the print head 200 is moved to one end in the cylindrical axis direction of the recording sheet held on the holding surface of the cylinder 100. Move up. The rotation of the cylinder 100 is regarded as main scanning, and the print head 200 is
Is moved in the direction of the cylinder axis of the cylinder 100 as a sub-scan, and the print head 200 ejects ink droplets to record an image in the image recording area of the recording sheet 1. Record the entire image. At this time, the distance between the print head 200 and the recording sheet 1 is restricted to 1 mm or less.

After the image recording is completed, the motor 2
The rotation of the pulley 250 causes the carriage 230 to move in the cylindrical axis direction of the cylinder 100, the print head 200 to move above the maintenance unit 600, and capping covering the ink ejection surface of the print head 200 with a cap. Done.

The image recording apparatus of this embodiment has a discharge guide 350 for separating the recording sheet 1 on which an image is recorded from the cylinder 100 and discharging the recording sheet 1, and a guide cylinder 100.
And a discharge tray 310 provided on the side of the cylinder 1.
The recording sheet 1 on which the image has been recorded at 00
Discharge to 0.

The discharge guide 350 extends from the side of the holding surface of the cylinder 100 to the discharge tray 310 so that the recording sheet 1
The recording sheet 1 released from the fixed holding by the cylinder 100 is guided to the discharge tray 310 by gravity. Then, the recording sheet 1 is discharged to the discharge tray 310 with the image recording surface facing up.

The discharge tray 310 has a plurality of recording sheets 1
Can be accommodated. In addition, the discharge tray 310
The recording sheet 1 is provided obliquely so that the height on the side of the cylinder 100 is increased, and accommodates the discharged recording sheet 1 obliquely.

The discharge tray 310 has a bat 330 which can be slid in the direction shown by the arrow in FIG. 2, and stores the discharged recording sheet 1 in a state where the bat 330 is slid out. . When the sheet cassette 500 is replaced, the recording sheet 1 cannot be supplied from the sheet cassette 500, so that the bat 330 can be pushed in.
Since the sheet cassette 500 is replaced, the sheet cassette 500 can be easily replaced.

Further, a heater may be provided inside the cylinder 100, an infrared lamp may be provided at a position facing the discharge guide 350, or the print head 20 of the carriage 230 may be provided.
For example, an infrared lamp is provided at a position next to the recording sheet 1, and the recording sheet 1 is ejected from the print head 200 onto the image recording surface of the recording sheet 1 until the recording sheet 1 is discharged to the discharge tray 310. The structure is to dry.

In the image recording apparatus of this embodiment, the cylinder 1
00, an electrostatic attraction sheet 40 is provided on the outer peripheral surface,
It is preferable that the recording sheet 1 is disposed at least at a position where the front end portion 1a and the rear end portion 1b are located. In FIG. 2, the electrostatic adsorption sheet 40 is disposed so as to substantially cover the outer peripheral surface of the cylinder 100. The outer peripheral surface of the suction sheet 40 corresponds to the holding surface of the cylinder of the present invention.

The electrostatic attraction sheet 40 is disposed on almost the entire outer peripheral surface of the cylinder 100.
A predetermined voltage from 1 is applied. In contrast, for example,
The pair of electrostatic attraction sheets 40 is the leading end 1 of the recording sheet 1.
a and the rear end 1b may be embedded in the peripheral surface of the cylinder 100 at the portion where the recording sheet 1 is located.
May be embedded in the peripheral surface of the cylinder 100 at the position where is located.

The cylinder 100 is rotated in the feeding direction, and the fed recording sheet 1 is fixedly held on the holding surface of the cylinder 100 by electrostatic attraction while being brought into close contact with the pressing roller 460. Accordingly, the recording sheet 1 is fixedly held on the surface of the cylinder 100 by electrostatic attraction, and an image is recorded by the print head 200 in a state where the recording sheet 1 is electrostatically attracted. ,
There are no traces or broken traces of the presser nails on the recording sheet 1. Further, it is easy to balance the wheel of the cylinder 100, so that the rotation unevenness of the cylinder is reduced.

The cylinder 100 is rotated in the feeding direction to rotate the cylinder 10
When the recording sheet 1 is fixedly held on the holding surface of the recording sheet 1 by electrostatic attraction, for example, when two or more recording sheets 1 are fed in an overlapping manner, the second or more recording sheet 1 from the holding surface
In order to discharge the toner, the cylinder 100 is rotated in the discharge direction opposite to the feeding direction, separated by the tip 351 of the discharge guide 350, and discharged by the discharge guide 350.

When recording an image, the cylinder 10
0 is rotated in the recording direction, which is the same rotation direction as the feeding direction, while one recording sheet 1 is fixedly held by electrostatic attraction. When the recording sheet 1 on which the image is recorded is discharged, the application of the voltage from the power supply 41 is interrupted or the reverse voltage is applied to release the electrostatic attraction, and the cylinder 100 is rotated in the direction opposite to the recording direction. And the recording sheet 1 is separated from the rear end 1b side of the recording sheet 1 by the leading end 351 of the discharging guide 350.
Discharge.

As described above, the discharge guide 350 also serves as a means for separating the recording sheet 1 on which the image is recorded from the cylinder 100, and has a small number of parts, and the image is recorded smoothly and reliably with a simple configuration. The recording sheet 1 can be discharged.

Further, there is no need to increase the accuracy of the separation mechanism in the feeding system, and the feeding mechanism is configured so that even if double feeding of the recording sheet 1 occurs, an unnecessary one sheet can be discharged, which hinders the recording operation. Disappears.

[0101]

As described above, according to the present invention, it is possible to smoothly discharge the second or more recording sheets which have been multi-fed, and to properly record an image on the recording sheets even if the recording sheets are multi-fed. .

[Brief description of the drawings]

FIG. 1 is a schematic perspective view in which a part of an image recording apparatus is broken.

FIG. 2 is a schematic front view of the internal structure of the image recording apparatus.

FIG. 3 is a view of the print head as viewed from its discharge direction.

[Explanation of symbols]

 Reference Signs List 1 recording sheet 40 electrostatic attraction sheet 41 power supply 460 pressing roller 100 cylinder 200 print head

Claims (24)

[Claims] A feeding step of feeding a recording sheet to a cylinder;
While rotating the cylinder in the feeding direction, a fixing process in which the fed recording sheet is fixedly held on the holding surface of the cylinder by electrostatic attraction, and when the recording sheet is multi-fed, the electrostatic attraction is used. Discharging the second or more recording sheets from the holding surface of the cylinder while holding the first recording sheet closest to the holding surface of the cylinder fixedly on the holding surface of the cylinder. An image recording method comprising the steps of: a double feeding / discharging step of rotating the cylinder; and an image recording step of recording an image on a recording sheet fixedly held on a holding surface of the cylinder. 2. The image recording method according to claim 1, wherein in the fixing step, the recording sheet is brought into close contact with a holding surface of the cylinder by a pressing roller. 3. The image recording method according to claim 1, wherein in the double feed discharging step, the cylinder is rotated in a discharging direction opposite to the feeding direction. 4. The image forming apparatus according to claim 1, wherein after the image recording step, the electrostatic attraction is released and the recording sheet is discharged from the holding surface of the cylinder. Image recording method. 5. The image recording method according to claim 4, wherein the recording sheet is discharged from a holding surface of the cylinder while rotating the cylinder in the discharge direction. 6. The image recording method according to claim 1, wherein an image is recorded on said recording sheet by ejecting ink droplets imagewise from a print head. 7. The image recording method according to claim 6, wherein said print head is an on-demand type print head in which a plurality of nozzles for ejecting ink droplets are arranged in parallel. 8. A color proof image corresponding to the color-separated halftone image data is recorded on the recording sheet according to image data corresponding to the color-separated halftone image data. Image recording method. 9. A cylinder for fixedly holding a recording sheet fed by said sheet feeding means on a holding surface by electrostatic attraction, a sheet feeding means for feeding the recording sheet to said cylinder, A cylinder rotating means for rotating the cylinder; and an image recording apparatus for recording an image on a recording sheet fixedly held on a holding surface of the cylinder, wherein the cylinder is fed by the cylinder rotating means. While rotating in the direction, the recording sheet fed by the sheet feeding means is fixedly held on the holding surface of the cylinder by electrostatic attraction, and when the recording sheet is multi-fed, the cylinder is The first recording sheet closest to the holding surface of the cylinder is fixedly held on the holding surface of the cylinder, and the second or more recording sheets are discharged from the holding surface of the cylinder. The cylinder is turned by rotating means, After image recording apparatus characterized by recording a fixedly image on a recording sheet held on the holding surface of the cylinder. 10. When the fed recording sheet is fixedly held on the holding surface of the cylinder by electrostatic attraction while rotating the cylinder in the feeding direction, the recording sheet is placed on the holding surface of the cylinder. The image recording apparatus according to claim 9, further comprising a pressing roller that makes close contact with the image recording apparatus. 11. When a recording sheet is multi-fed, a second or more recording sheet is held by said cylinder while holding one recording sheet fixedly on a holding surface of said cylinder by electrostatic attraction. In the process of turning the cylinder so as to discharge from the surface,
The image recording apparatus according to claim 9, wherein the cylinder is rotated in a discharge direction opposite to the feeding direction. 12. A sheet discharging means for discharging a recording sheet from a holding surface of the cylinder, and after recording an image on a recording sheet fixedly held on the holding surface of the cylinder, electrostatic adsorption is performed. The image recording apparatus according to any one of claims 9 to 11, wherein the recording sheet is released from the holding surface of the cylinder by the sheet discharging means after the release. 13. An image recording apparatus according to claim 12, wherein said sheet discharging means discharges the recording sheet from the holding surface of said cylinder without rubbing the image recording surface. 14. The image recording apparatus according to claim 13, wherein the recording sheet is discharged from a holding surface of the cylinder while rotating the cylinder in the discharge direction. 15. An image recording apparatus according to claim 9, further comprising a print head for ejecting ink droplets, wherein an image is recorded on said recording sheet by ejecting ink droplets imagewise from said print head. The image recording device according to claim 1. 16. The image recording apparatus according to claim 15, wherein said print head is an on-demand type print head in which a plurality of nozzles for ejecting ink droplets are arranged in parallel. 17. The apparatus according to claim 17, wherein said holding surface of said cylinder has a substantially cylindrical shape, and said cylinder rotating means turns said cylinder substantially around said cylindrical axis. Item 17. An image recording apparatus according to Item 16. 18. The method according to claim 18, wherein a cylindrical axis of the cylindrical surface is substantially horizontal.
18. The image recording apparatus according to claim 17, wherein the print head ejects ink droplets downward from a position above the recording sheet to record an image on the recording sheet. 19. A moving means for moving the print head in a direction parallel to the cylinder axis at least over an image recording width, wherein the plurality of nozzles are arranged in a direction substantially parallel to the cylinder axis. The image according to any one of claims 15 to 18, wherein a width of the plurality of nozzles arranged side by side (a width arranged side by side) is smaller than an image recording width. Recording device. 20. The image recording apparatus according to claim 19, further comprising regulating means for regulating a position of said print head in a direction perpendicular to said column axis. 21. The sheet feeding means according to claim 9, wherein said sheet feeding means feeds a recording sheet onto the holding surface of said cylinder without rubbing an image recording surface. Item 2. The image recording device according to item 1. 22. An image recording apparatus according to claim 21, wherein said sheet feeding means has a guide for guiding the back side of the recording sheet, and a pair of feeding rollers for feeding the recording sheet. apparatus. 23. A color proof image corresponding to the color separation image data is recorded on the recording sheet according to image data corresponding to the color separation image data. The image recording device according to claim 1. 24. The image recording apparatus according to claim 23, wherein said print head is provided for each primary color of color separation image data.