JP2011143588A - Image formation device and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image formation device and image forming method which suppress the deterioration in image-quality even if a small inkjet head is used. <P>SOLUTION: The image formation device 100 includes an intermediate transfer roller 11, an ink jet head 12 for forming an ink image on the intermediate transfer roller 11, a platen 20 for transferring the ink image formed on the intermediate transfer roller 11 to a paper P, an endless belt 31 for conveying the paper P, and a driving means for driving the intermediate transfer roller 11 and the inkjet head 12 in the nearly-vertical direction to the direction in which the paper P is conveyed in the region where the ink image formed on the intermediate transfer roller 11 is transferred to the paper P while transferring the ink image formed on the intermediate transfer roller 11 to the paper P. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming method.

  Examples of the inkjet method include a movable actuator method typified by a piezo method, a heated film boiling method typified by a thermal method, etc., but both methods are based on ejecting ink from nozzles according to image information. Then, an ink image is formed. The inkjet system is applied to image forming apparatuses such as a printer, a facsimile machine, and a copying machine because it has a simpler configuration than an electrophotographic system.

  In such an image forming apparatus, the main part of the image forming engine is composed of an ink jet head, ink, and paper, and paper is conveyed in an area close to the ink jet head, so paper dust, dust, etc. adhere to the nozzle. Cheap. As a result, the flying direction of the droplets ejected from the nozzle is disturbed or the nozzle is blocked, resulting in a reduction in image quality and reliability.

  Therefore, a method is known in which ink is ejected from an ink jet head to form an ink image on an intermediate transfer member and then transferred to paper.

  FIG. 7 of Patent Document 1 shows that a small ink-jet head repeatedly reciprocates in the direction of the rotation axis of the intermediate transfer roller, and the intermediate transfer roller rotates intermittently, thereby intermittently forming a belt-like image on the intermediate transfer roller. A method of forming is disclosed.

  However, there is a problem in that dot misalignment occurs and image quality deteriorates.

  An object of the present invention is to provide an image forming apparatus and an image forming method capable of suppressing deterioration in image quality even when a small inkjet head is used.

  According to the first aspect of the present invention, in the image forming apparatus, the intermediate transfer member, the inkjet head that forms an ink image on the intermediate transfer member, and the ink image formed on the intermediate transfer member are transferred to the transfer target. A transfer unit; a transfer unit configured to transfer the transfer object; the intermediate transfer member and the inkjet head; and an ink image formed on the intermediate transfer member while transferring the ink image to the transfer member. And a driving unit configured to drive a region where the formed ink image is transferred to the transfer target in a direction substantially perpendicular to a direction in which the transfer target is conveyed.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the image forming apparatus further includes a cleaning member that cleans the intermediate transfer body on which the ink image is transferred to the transfer target body. It is driven together with the intermediate transfer member and the inkjet head.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the driving unit is configured to transfer the intermediate transfer body, the inkjet head, and the cleaning member to the ink image formed on the intermediate transfer body. While being transferred to the transfer target, it is driven back and forth, and the cleaning member transfers the ink image to the transfer target in accordance with the direction of driving the intermediate transfer member, the inkjet head, and the cleaning member. Further, two are provided so as to clean the intermediate transfer member.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the two cleaning members can be brought into contact with and separated from the intermediate transfer member.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the second to fourth aspects, the cleaning member has a blade shape.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the second to fifth aspects, the length of the cleaning member in a direction in which the transfer target is conveyed is greater than that of the intermediate transfer member. It is also characterized by its long length.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect of the present invention, the image forming apparatus further includes a cleaning member that cleans both ends of the intermediate transfer body in a direction in which the transfer target is conveyed. .

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the ink image formed on the intermediate transfer body is transferred from the vertically lower side to the transferred body. It is characterized by that.

  According to a ninth aspect of the present invention, in the image forming method, the step of forming an ink image on the intermediate transfer member using an inkjet head, and the step of transferring the ink image formed on the intermediate transfer member to the transfer target When the ink image formed on the intermediate transfer body is transferred to the transfer target body, the ink image formed on the intermediate transfer body is transferred without transferring the transfer target body. When the image is not transferred to a body, the intermediate transfer body is transported, and the intermediate transfer body and the inkjet head transfer the ink image formed on the intermediate transfer body to the transfer body while transferring the intermediate transfer body. A region in which an ink image formed on a body is transferred to the transfer target is driven in a direction substantially perpendicular to a direction in which the transfer target is conveyed.

  According to the present invention, it is possible to provide an image forming apparatus and an image forming method capable of suppressing deterioration in image quality even when a small inkjet head is used.

It is a figure which shows an example of the image forming apparatus of this invention. FIG. 2 is a diagram illustrating a direction in which the image forming module of FIG. 1 is driven. It is a figure which shows a liquid ring. It is a figure which shows liquid adhesion. FIG. 8 is a diagram illustrating a modification of the image forming module in FIG. 1. It is a figure which shows the image forming method using the image forming apparatus of FIG. It is a figure which shows the image forming method using the image forming apparatus of FIG. FIG. 8 is a diagram illustrating a modification of the image forming module in FIG. 1. It is a figure which shows the modification of the image forming method of FIG. It is a figure which shows the modification of the image forming method of FIG. It is a figure which shows the modification of the image forming apparatus of this invention. It is a figure which shows the modification of the image forming apparatus of this invention.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows an example of an image forming apparatus of the present invention. The image forming apparatus 100 includes an intermediate transfer roller 11, an inkjet head 12 that forms an ink image on the intermediate transfer roller 11, and a cleaning blade 13 that cleans the intermediate transfer roller 11 on which the ink image has been transferred onto paper P. It has a module 10. At this time, the ink image formed on the intermediate transfer roller 11 is transferred onto the paper P using the platen 20. The image forming apparatus 100 also includes an endless belt 31 that transports the paper P, a driving roller 32 and a driven roller 33 around which the endless belt 31 is stretched, and a charging roller 34 that charges the endless belt 31 between the driven roller 33 and the image forming apparatus 100. It has the conveyance apparatus 30 which consists of these.

  As shown in FIG. 2, the image forming module 10 is driven by driving means (not shown) applied to a general serial type or shuttle type ink jet system. At this time, the direction A in which the image forming module 10 is driven is the direction B in which the paper P is conveyed in an area where the ink image formed on the intermediate transfer roller 11 is transferred to the paper P (hereinafter referred to as a transfer area). On the other hand, it is substantially vertical. Further, the intermediate transfer roller 11 abuts on the paper P or the endless belt 31 and rotates.

  The driving method of the image forming module 10 is not particularly limited. For example, the image forming module 10 may be driven by rotating the intermediate transfer roller 11 using a driving unit such as a motor or a speed reduction mechanism. Good.

  The outer diameter of the intermediate transfer roller 11 is usually 6 to 40 mm, and preferably 10 to 20 mm. If the outer diameter of the intermediate transfer roller 11 is less than 10 mm, it may be difficult to clean the intermediate transfer roller 11 on which the ink image has been transferred to the paper P. If it exceeds 20 mm, the image forming apparatus 100 is reduced in size. It may be difficult to convert.

  Further, the length of the intermediate transfer roller 11 in the rotation axis direction is not particularly limited as long as it is longer than the length of the nozzle row of the inkjet head 12, and is usually 15 to 80 mm, and preferably 35 to 50 mm. If the length of the intermediate transfer roller 11 in the rotation axis direction is less than 35 mm, the image forming speed may not be practical, and if it exceeds 50 mm, it is difficult to reduce the size of the image forming apparatus 100. Sometimes.

  In consideration of the high-speed drive response of the image forming module 10, the intermediate transfer roller 11 is preferably lightweight.

  In consideration of the transferability of the ink image to the paper P, the intermediate transfer roller 11 preferably deforms following the unevenness formed by the fibers of the paper P and has a small surface energy. For example, the outer diameter is 16 mm. The intermediate transfer roller 11 in which a silicone rubber layer having a thickness of 1 mm is formed on an aluminum core member having a length of 38 mm can be used. Further, instead of the silicone rubber layer, a urethane-based or nitrile butadiene-based rubber layer subjected to fluorine treatment may be formed.

  Since the inkjet head 12 is usually manufactured using a fine processing method using a silicon wafer or the like, the length of the nozzle row is about 0.5 to 1.5 inches. For example, the length of the nozzle row is The GX series (made by Ricoh) inkjet head 12 which is 1.27 inches (3.23 cm) can be used.

  The gap between the intermediate transfer roller 11 and the inkjet head 12 is not particularly limited as long as the intermediate transfer roller 11 can rotate. By shortening the length of the intermediate transfer roller 11 and the inkjet head 12, for example, It can be made 100 μm or less, and the ink landing accuracy can be improved.

  The cleaning blade 13 is brought into contact with the intermediate transfer roller 11 in order to remove ink components remaining on the surface of the intermediate transfer roller 11, paper dust, dust, and the like of the paper P.

  Considering that the cleaning blade 13 does not hinder the rotation of the intermediate transfer roller 11, it is preferable that the friction resistance is small. For example, a cleaning blade 13 made of fluoro rubber can be used. Further, instead of fluoro rubber, urethane or nitrile butadiene rubber may be used, or the surface of the rubber may be subjected to fluorine treatment. Further, a metal such as stainless steel or nickel may be used instead of the fluoro rubber.

  The length of the cleaning blade 13 in the rotation axis direction of the intermediate transfer roller 11 is not particularly limited as long as the intermediate transfer roller 11 can be cleaned, but the intermediate transfer roller 11 of the intermediate transfer roller 11 in the rotation axis direction is not particularly limited. It is preferable that the length is longer than the length. When the length of the intermediate transfer roller 11 in the rotation axis direction of the cleaning blade 13 is shorter than the length of the intermediate transfer roller 11 in the rotation axis direction, a liquid ring R is generated as shown in FIG. An abnormal image may be formed. The liquid ring R is generated when ink components accumulated in the cleaning blade 13 by cleaning the intermediate transfer roller 11 leak from both ends of the intermediate transfer roller 11 in the rotation axis direction.

  Further, when the image forming apparatus 100 is used, after the ink corresponding to the idle ejection is ejected to the rotationally driven intermediate transfer roller 11, the ink can be removed using the cleaning blade 13 without being transferred to the paper P. it can. For this reason, it is considered that an empty discharge portion that is generally provided to maintain the nozzle row of the inkjet head 12 can be omitted. In this case, since a large amount of ink component is removed by the cleaning blade 13, the ink removed by the cleaning blade 13 wraps around both end surfaces of the intermediate transfer roller 11 in the rotation axis direction as shown in FIG. R ′ may occur and the paper P may be contaminated. For this reason, as shown in FIG. 5, a cleaning blade 14 for cleaning both end surfaces of the intermediate transfer roller 11 in the rotation axis direction may be further provided. At this time, it is preferable that the cleaning blade 14 cleans a contact portion with the cleaning blade 13 on both end surfaces of the intermediate transfer roller 11 in the rotation axis direction. Thereby, generation | occurrence | production of liquid adhesion R 'can be avoided effectively.

  Considering that the cleaning blade 14 does not hinder the rotation of the intermediate transfer roller 11, it is preferable that the frictional resistance is small. For example, a cleaning blade 14 made of fluoro rubber can be used. Further, instead of fluoro rubber, urethane or nitrile butadiene rubber may be used, or the surface of the rubber may be subjected to fluorine treatment. Further, a metal such as stainless steel or nickel may be used instead of the fluoro rubber.

  The length of the cleaning blade 14 is not particularly limited as long as both end surfaces of the intermediate transfer roller 11 in the rotation axis direction can be cleaned.

  A cleaning member in which the cleaning blades 13 and 14 are integrated may be used.

  Since the image forming module 10 is installed vertically below the conveying device 30 in the image forming apparatus 100, the ink component removed by the cleaning blade 13 can be prevented from falling and contaminating the paper P.

  Note that the image forming module 10 may be installed vertically above the conveying device 30 if a guard member or the like that prevents the ink component removed by the cleaning blade 13 from falling is installed.

  The platen 20 is installed in the transfer area so as to substantially contact the surface of the endless belt 31 on the side where the intermediate transfer roller 11 does not contact.

  The endless belt 31 is not particularly limited as long as it is made of an insulating material. For example, an endless belt 31 made of polyimide having a thickness of 60 μm can be used. Further, polycarbonate, PET, or the like may be used instead of polyimide.

  The driving roller 32 is rotationally driven by driving means (not shown) such as a motor.

  The driven roller 33 is not particularly limited as long as it is made of a conductive material, but a stainless driven roller 33 can be used. Moreover, you may use the driven roller 33 by which the rubber layer to which electroconductivity is provided by carbon etc. is formed in metal core materials.

The charging roller 34 preferably has a resistance layer having a volume resistivity of about 1 × 10 ⁶ to 1 × 10 ¹⁰ Ω · cm formed on the surface thereof. For example, the volume resistance of the metal roller is made of carbon or the like. It is possible to use a charging roller 34 on which a rubber layer whose rate is adjusted is formed. Further, instead of the rubber layer, a resin layer whose volume resistivity is adjusted by carbon or the like may be formed, or a rubber layer having ion conductivity such as epichlorohydrin rubber may be formed.

  The charging roller 34 is connected to an AC high voltage power source (not shown) capable of repeating discharge and non-discharge. As the endless belt 31 moves, a charging region (potential of about 1000 V) is formed on the surface of the endless belt 31. ) And a non-charged region (a potential of about 0 V) are sequentially formed. At this time, it is preferable that the charged region and the non-charged region have a linear repeating pattern with a period of about 1 to 2 mm. The endless belt 31 in which the charged area and the non-charged area are formed can adsorb the paper P by an electrostatic attraction force acting on the edge portion of the charged area. As a result, the transport device 30 can transport the paper P stably while adsorbing the paper P vertically below the endless belt 31.

  Instead of using the charging roller 34, the paper P may be attracted to the endless belt 31 by air suction, or the paper P may be transported using a plurality of transport rollers, transport guides, or the like.

  Further, instead of transporting the paper P in the direction perpendicular to the vertical direction, the paper P may be transported in the vertical direction.

  Next, a method for forming an image on the paper P using the image forming apparatus 100 will be described. First, the paper P is transported to the transfer area by the transport device 30 and stops. At this time, in the image forming module 10, the intermediate transfer roller 11 and the endless belt are separated from the intermediate transfer roller 11 and the endless belt 31 by a contact / separation unit (not shown) so that the gap is about 1 mm. 31 will be in contact. Further, almost simultaneously with the image forming module 10 being driven by a driving means (not shown), ink is ejected from the inkjet head 12 to the intermediate transfer roller 11 based on the image signal, and an ink image is formed on the intermediate transfer roller 11. Is formed. As a result, when the intermediate transfer roller 11 rotates approximately half a circle, the ink image is transferred to the paper P, and a belt-like image I is formed (see FIG. 6). At this time, as shown in FIG. 7A, the image forming module 10 is driven from a position that is separated from the position where the transfer of the paper P is started by a running distance C corresponding to the rotational movement distance of the intermediate transfer roller 11. The

  On the other hand, along with the rotation of the intermediate transfer roller 11, ink components remaining on the intermediate transfer roller 11 on which the ink image has been transferred to the paper P, paper dust, dust, and the like on the paper P are removed by the cleaning blade 13 and are discarded. It is collected in a waste collection container (not shown) via a collection path (not shown).

  At this time, since the image forming module 10 has one cleaning blade 13, the direction of driving the image forming module 10 is limited to one direction while transferring the ink image formed on the intermediate transfer roller 11 to the paper P. As a result, it is possible to suppress deterioration in image quality. Specifically, as shown in FIG. 7B, the image forming module 10 forms the belt-like image I on the paper P, and when the intermediate transfer roller 11 and the paper P are not in contact with each other, the contact / separation means After being separated so that the gap between the intermediate transfer roller 11 and the endless belt 31 is about 1 mm by (not shown), it is driven by driving means (not shown) to return to the original position.

  When the belt-like image I is further formed on the paper P, during this time, the transport device 30 transports the paper P by the width of the belt-like image I and stops. At this time, the image forming module 10 returns to a state in which the intermediate transfer roller 11 and the endless belt 31 are in contact with each other by a contact / separation unit (not shown). On the other hand, when the belt-like image I is not further formed on the paper P, the image forming module 10 stands by in a state where the intermediate transfer roller 11 and the endless belt 31 are separated from each other, and the transport device 30 transports the paper P, Discharge.

  FIG. 8 shows a modification of the image forming module 10. The image forming module 10 ′ has two cleaning blades 13, except that the two cleaning blades 13 A and 13 B can be brought into and out of contact with the intermediate transfer roller 11 by contact / separation means (not shown) such as a clutch. The configuration is the same as that of the image forming module 10.

  In the image forming apparatus 100, when the image forming module 10 ′ is used instead of the image forming module 10, the image forming module is configured to transfer the ink image formed on the intermediate transfer roller 11 onto the paper P as shown in FIG. Even if 10 ′ is reciprocally driven, deterioration in image quality can be suppressed, and an image can be formed at high speed. Specifically, as shown in FIG. 10A, the image forming module 10 ′ is in a state where the intermediate transfer roller 11 and the cleaning blade 13A are in contact with each other, and the intermediate transfer roller 11 and the cleaning blade 13B are separated from each other. A belt-like image I is formed on the paper P. At this time, as shown in FIG. 10B, the image forming module 10 ′ stops at a position separated from the position where the transfer of the paper P is started by a running distance C corresponding to the rotational movement distance of the intermediate transfer roller 11. To do. At this time, in the image forming module 10 ′, the intermediate transfer roller 11 and the cleaning blade 13A are separated from each other, and the intermediate transfer roller 11 and the cleaning blade 13B are in contact with each other. Further, the image forming module 10 ′ is separated by the contact / separation means (not shown) so that the gap between the intermediate transfer roller 11 and the endless belt 31 is about 1 mm, and then the intermediate transfer roller 11 and the endless belt 31 are contacted. Return to contact. While the intermediate transfer roller 11 and the endless belt 31 are separated from each other, the conveying device 30 conveys the sheet P by the width of the band-shaped image I and stops. Next, the image forming module 10 forms the belt-like image I on the paper P, and stops at a position separated from the position at which the transfer of the paper P is started by a running distance C corresponding to the rotational movement distance of the intermediate transfer roller 11. . At this time, the image forming module 10 ′ returns to a state in which the intermediate transfer roller 11 and the cleaning blade 13A are in contact with each other, and the intermediate transfer roller 11 and the cleaning blade 13B are in contact with each other.

  When the belt-like image I is further formed on the paper P, the image forming module 10 ′ is separated by the contact / separation means (not shown) so that the gap between the intermediate transfer roller 11 and the endless belt 31 is about 1 mm. It returns to the normal state where the intermediate transfer roller 11 and the endless belt 31 are in contact. While the intermediate transfer roller 11 and the endless belt 31 are separated from each other, the conveying device 30 conveys the sheet P by the width of the band-shaped image I and stops. On the other hand, when the belt-like image I is not further formed on the paper P, the image forming module 10 ′ is separated by the contacting / separating means (not shown) so that the gap between the intermediate transfer roller 11 and the endless belt 31 is about 1 mm. Thereafter, the intermediate transfer roller 11 and the endless belt 31 are in a standby state, and the conveying device 30 conveys and discharges the paper P.

  FIG. 11 shows a modification of the image forming apparatus of the present invention. The image forming apparatus 200 has the same configuration as the image forming apparatus 100 except that a full color image forming module including four image forming modules 10 ′ is used instead of the image forming module 10. The four image forming modules 10A ′, 10B ′, 10C ′, and 10D ′ correspond to yellow, magenta, cyan, and black, respectively. Further, the full-color image forming module stops at a position separated from the position at which the transfer of the paper P is started by a running distance C corresponding to the rotational movement distance of the intermediate transfer roller 11 closest to the paper P.

  The image forming module 10 may be used instead of the image forming module 10 ′.

  FIG. 12 shows a modification of the image forming apparatus of the present invention. The image forming apparatus 300 uses the full-color image forming module having the same configuration as the image forming module 10 ′ except that the image forming module 300 has four inkjet heads 12 instead of the image forming module 10. It is the same composition as. The four inkjet heads 12A, 12B, 12C, and 12D correspond to yellow, magenta, cyan, and black, respectively. In the image forming apparatus 300, although the outer diameter of the intermediate transfer roller 11 tends to increase, the number of the cleaning blades 13 can be reduced.

  The cleaning blade 13B may be omitted, and the direction in which the full color image forming module is driven while the ink image formed on the intermediate transfer roller 11 is transferred to the paper P may be limited to one direction.

  Further, the number of inkjet heads 12 may be reduced and combined with the image forming module 10 ′.

  Further, as the ink, a known ink can be used.

  As described above, the configuration using the intermediate transfer roller 11 as the intermediate transfer member has been described. However, an endless belt stretched by a plurality of rollers may be used instead of the intermediate transfer roller 11, or a sleeve without tension. May be used.

  Moreover, although the structure which uses the paper P as a non-transfer body was demonstrated, instead of the paper P, ... may be used.

DESCRIPTION OF SYMBOLS 10 Image forming module 11 Intermediate transfer roller 12 Inkjet head 13, 14 Cleaning blade 20 Platen 30 Conveying device 31 Endless belt 32 Drive roller 33 Driven roller 34 Charging roller 100, 200, 300 Image forming apparatus P Paper A Image forming module is driven Direction B

WO94 / 001283 Publication

Claims (9)

An intermediate transfer member;
An ink jet head for forming an ink image on the intermediate transfer member;
Transfer means for transferring the ink image formed on the intermediate transfer member to the transfer target;
Conveying means for conveying the transfer object;
A region where the ink image formed on the intermediate transfer body is transferred to the transfer body while the intermediate transfer body and the inkjet head transfer the ink image formed on the intermediate transfer body to the transfer body. An image forming apparatus comprising: a driving unit that drives the transfer member in a direction substantially perpendicular to a direction in which the transfer target is conveyed. A cleaning member that cleans the intermediate transfer body on which the ink image is transferred to the transfer body;
The image forming apparatus according to claim 1, wherein the cleaning member is driven together with the intermediate transfer member and the inkjet head. The driving means reciprocates the intermediate transfer body, the inkjet head, and the cleaning member while transferring an ink image formed on the intermediate transfer body to the transfer target body.
Two cleaning members are provided so as to clean the intermediate transfer body on which the ink image has been transferred to the transfer target body in accordance with the direction in which the intermediate transfer body, the inkjet head, and the cleaning member are driven. The image forming apparatus according to claim 2, wherein the image forming apparatus is provided.   The image forming apparatus according to claim 3, wherein each of the two cleaning members is movable toward and away from the intermediate transfer member.   The image forming apparatus according to claim 2, wherein the cleaning member has a blade shape.   The image forming apparatus according to claim 2, wherein the cleaning member has a length in a direction in which the transfer target is conveyed longer than that of the intermediate transfer member.   The image forming apparatus according to claim 6, further comprising a cleaning member that cleans both ends of the intermediate transfer member in a direction in which the transfer target is conveyed.   The image forming apparatus according to claim 1, wherein the ink image formed on the intermediate transfer member is transferred to the transfer target member from below in the vertical direction. Forming an ink image on the intermediate transfer member using an inkjet head; and
A step of transferring an ink image formed on the intermediate transfer member to a transfer target;
When the ink image formed on the intermediate transfer member is transferred to the transfer target, the transfer target is not conveyed,
When the ink image formed on the intermediate transfer body has not been transferred to the transfer body, the transfer body is transported,
A region where the ink image formed on the intermediate transfer body is transferred to the transfer body while the intermediate transfer body and the inkjet head transfer the ink image formed on the intermediate transfer body to the transfer body. Is driven in a direction substantially perpendicular to the direction in which the transfer object is conveyed.

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